Wikipedia:Reference desk archive/Science/December 2005

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December 1[edit]

Natural fuel resources[edit]

Which countries have natural fuel resources?

I suppose pretty much all countries will have some coal, gas or oil. Whether that is commercially interresting and actually exploited is a different matter. You might look at opec, List of oil fields and List of natural gas fields. DirkvdM 10:36, 2 December 2005 (UTC)
Also several countries have big biofuel resources (ie big forests). TERdON 03:32, 6 December 2005 (UTC)
  • Sunlight can be used for solar heating most places.
  • Nations with coastlines and rivers can use hydro electric.
  • There is such a thing as wind power where windmills can generate electricity.
  • Some nations have geothermic heat in sufficient quantities to generate useable energy.

AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 02:06, 9 December 2005 (UTC)

Nuclear fusion in the sun[edit]

FusionintheSun.png

I've known for a long time that in the sun four hydrogen atoms fuse to make a helium atom. I never really thought about it much, but just recently I realized that four protons fusing together should make beryllium, not helium. I read some of the article Nuclear fusion and it had a pretty cool pic...Image:FusionintheSun.png, but I didn't understand most of it. Also, the pic shows the creation of a positron. What in the heck is a positron? (Supposedly the anti-matter of an electron, whatever that means) Lol! Again, over my head. Anyway, I was just wondering. Thanks to everyone in advance! Dimblethum 03:14, 1 December 2005 (UTC)Dimblethum

I'm not a physicist, but the figure seems to indicate that you can produce a neutron by releasing positron from a proton. A positron is the antiparticle of an electron. --JWSchmidt 03:35, 1 December 2005 (UTC)
That's also right, there's also a neutrino involved, but they're pretty damn hard to see. There are two weak decays that affect nuclei, and they are:
p \to n + e^+ + \nu
n \to p + e^- + \overline{\nu}
Where p is a proton, n is a neutron, e+ is a positron, e- is an electron, and ν indicates a neutrino (or an antineutrino if there's a bar over it). Hope that helps; if you have more questions, ask them. -- SCZenz 03:51, 1 December 2005 (UTC)
You're correct that four protons in a nucleus would make beryllium; however it is more complicated than that; a nucleus with four protons and no neutrons would be highly unstable. The reactions are detailed in proton-proton chain reaction and are too complex for me to fully explain here, but I'll try summarize. The key is the initial proton-proton reaction. Two protons come together, and one proton is converted into a neutron (an up quark transforms into a down quark I believe). In the process, a positron is emitted, which as JWSchmidt indicates is the antiparticle of an electron (see that article, or antimatter if you are not familiar with the concept—basically each particle has a corresponding antiparticle with opposite charge, spin, etc.; when a particle and antiparticle collide, they annihilate each other and produce energy via E=mc2. This, for instance, is the basis of the matter-antimatter reactor that powers the Enterprise in Star Trek and in other science fiction. Antiparticles are normally simply named by adding anti- to the particle name; positrons are a historical exception). Also emitted is an electron neutrino. The positron will quickly meet an electron and mutually annhiliate. The rest is covered in proton-proton chain reaction; if there are specific questions you have or concepts you don't understand, ask them here. — Knowledge Seeker 03:47, 1 December 2005 (UTC)
One final suggestion. If you don't understand what a positron is still, reading the antimatter article will hopefully help. -- SCZenz 03:59, 1 December 2005 (UTC)
All stable nuclei have a ratio of protons to neutrons that falls within a certain range (see Isotope table (divided)). If there are too many protons, some can turn into neutrons by beta decay, and vice versa. A proton can change into a neutron by emitting a positron (beta plus), and a neutron can change into a proton by emitting an electron (beta minus). —Keenan Pepper 03:59, 1 December 2005 (UTC)

THE SUN DOES NOT EXIST!!!!!

Electrotheremin construction[edit]

I'm looking to build an electrotheremin, which as I understand it is just an audio oscillator with a slide potentiometer determining pitch. However, I don't really have experience with electronics, so I can't just "wing it." Is there a place on the internet or something where I could find the schematic for such an oscillator? Or, is there a simple step for replacing a resistor in an existing oscillator circuit with the slide potentiometer? Thanks in advance. --ParkerHiggins 03:17, 1 December 2005 (UTC)

Yes, if you already have an oscillator circuit you could replace the resistor with a slide potentiometer. Or even simpler, you could just add the potentiometer in parallel with the resistor, which wouldn't require breaking the original circuit. —Keenan Pepper 15:24, 1 December 2005 (UTC)

Insulin Structure[edit]

I'm doing a school project for my grade 12 biology class and I need to make a physical insulin structure. Within my structure, needs to be the appropriate sequence of amino acids to form an insulin protein. So far, the types of insulin structures I've found on the web consist of the "leader chain, A-chain, B-chain, and C-chain". These descriptions are not what I'm looking for. I need to know the exact sequence of amino acids in these chains that make up insulin. Thank-you very much for your help.:)

See this page. The structure shown is bovine insulin; if you want to make a model of human insulin be sure to make the substitutions shown at the top of the page. You also have to decide on what form of insulin you are modeling: the kind that is found in the circulation (insulin proper, which is shown there) or the one which is transcribed from the RNA and processed to become that form (proinsulin). The leader-chain and C-peptide won't be found in the circulating form. (BTW, searching for "insulin amino acid sequence" would find this for you). - Nunh-huh 03:54, 1 December 2005 (UTC)
More resources: A B C chains <-- nice diagram, the three letter codes (and single letter codes) for all the amino acids are at amino acid. This figure shows a diagram of the entire 110 amino acids, including the leader segment. The entire 110 amino acids (single letter code) are listed here: Translation (110 aa). --JWSchmidt 04:38, 1 December 2005 (UTC)

Measuring Electromagnetic Radiation (EMR)[edit]

Two part question:

What type of instrument is used to measure the amount of EMR put out by a small appliance.

What types of flexible matierials block EMR (i.e., mesh, aluminum, kevlar)?

Thank you. 71.140.225.157 03:46, 1 December 2005 (UTC)

Any conductive material, if wrapped around the appliance without large holes, forms a Faraday cage that blocks low-frequency electromagnetic faradiation. The maximum allowable hole size depends on the highest frequency that needs to be blocked. —Ilmari Karonen (talk) 16:55, 1 December 2005 (UTC)

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How LEDs actually work[edit]

Well, you might ask a question. But in lieu of that, may I suggest you check out Light-emitting diode? --ParkerHiggins 06:48, 1 December 2005 (UTC)

*.m4a to *.wma[edit]

How can one convert a .m4a file format (songs from iTunes) to *.wma file format (so i can play them in windows media player...)?

There's a winamp plugin that lets it play m4a. So you can use winamp to play them, or you can use winamp to decode it to a wav (and then you can use any of a dozen programs to reencode it as an mp3) Raul654 10:58, 1 December 2005 (UTC)
However, note that every time you convert from one lossy format to another, it sounds a little worse. Encoding from the original source is always better. —Keenan Pepper 15:20, 1 December 2005 (UTC)

Cookie files[edit]

Does anyone know why the term "cookie" was used in the first place? (I can see the link for developing the brownie project, but why did he choose "cookie" to start with)? All ideas gratefully accepted. Jax1402

The original, full term is magic cookie. I think it may have originated at MIT; MIT-MAGIC-COOKIE-1 is an authentication method used by the X Window System. —Keenan Pepper 18:05, 1 December 2005 (UTC)

How do you "turn off" a magnet?[edit]

How do you turn off a magnet?

This is NOT an electro-magnet.

I have a magnetic base for a measuring device that allows you to attach the measuring device to metal objects. The magnetic base has a switch that allows you to turn the magnet on or off. When on, the magnet is very powerfull, and when off, it will attract and hold a paper clip but nothing bigger.

I dissassembled the magnetic base on found that it consists of a block of metal with a cylindrical hole drilled thru its center. In the hole is a cynlindrical magnet. The switch rotates the cylindrical magnet 90 degrees. The outer block does not have any measurable magnetism.

Your description is a bit value, but I'll assume the dipole axis of the magnet is perpendicular to the axis of the cylinder, i.e. that rotating the magnet in the hole moves the poles, and that in the "on" position one of the poles points towards the bottom of the base. That pole then strongly attracts adjacent ferromagnetic objects. When you rotate the magnet 90°, both poles as now facing the sides of the base (where there is presumably quite a lot of padding between the magnet and the exterior of the base), while the side of the magnet produces only a weak residual attraction. —Ilmari Karonen (talk) 16:44, 1 December 2005 (UTC)
  • Actually, it's usually the opposite way around. When the magnet is "off", the dipole points up and down. When it is "on", the rotating magnet has its N pole in one half of the base, and the S pole in the other half. The two halves of the base plus the rotating magnet form a sort of horseshoe magnet. When its attached to a piece of metal (across the two halves of the base) it makes a magnetic circuit which it is very strong. When it is switched off, there's a much smaller residual magnetism. These sort of bases are used a lot in optical experiments to position devices on optical benches. See here: U.S. Patent 4,251,791 for one design. --Bob Mellish 21:34, 1 December 2005 (UTC)

Heat it up --Eye 21:37, 1 December 2005 (UTC)

I agree with Eye - what you want to do is to disrupt the alignment of the dipoles in some manner. Nothing quite like heating or hitting the magnet. --HappyCamper 03:32, 3 December 2005 (UTC)

Degaussing. ☢ Ҡieff 01:30, 6 December 2005 (UTC)

I should point out that heating it up will permanently destroy the magnetism. (Well, for a given value of "permanently". You can make it magnetic again, but it won't become magnetic again by itself.) DS 01:03, 10 December 2005 (UTC)

What to do with an extra satellite dish?[edit]

Last week an article about a guy with a dozen satellite dishes outside his house was linked everywhere on the internet. This morning I stopped by my mothers house and they recently had their DirectTV dish replaced with one that can pick up local channels. They got to keep their old dish...until I stole it from them. What do I need to do to set this sucker up on my apartment balcony and start getting news feeds, local channels from other states, and shows in languages I don't speak?

I know I need a receiver but could I just use a computer and some software made for this?

Is there any other fun things I can do with this dish?

Frisbee! Make a giant Pu pu platter! Makes a great shield for those slow Dungeons and Dragons game nights. You need an account for those dishes, so I doubt you will pick up much free programming. Dominick (TALK) 19:08, 1 December 2005 (UTC)

It'd make a tremendous parabolic microphone. –Mysid 10:51, 2 December 2005 (UTC)
Snowboard! smurrayinchester(User), (Ho Ho Ho!) 12:51, 2 December 2005 (UTC)
Point it straight up and try to beat SETI to the punch. --Kainaw (talk) 02:54, 3 December 2005 (UTC)
Bird bath? TenOfAllTrades(talk) 03:23, 3 December 2005 (UTC)

Microbrewing[edit]

How does micro brewing work?

See Microbrew. I think it's just like regular brewing, only on a smaller scale. Homebrewing is even smaller. —Keenan Pepper 18:12, 1 December 2005 (UTC)
Microbrewery too. --HappyCamper 03:31, 3 December 2005 (UTC)

Mathematics[edit]

What is the maximum number of vertices with 15 edges and three components?

If you have V vertices and E edges, the minimum number of components is V − E (because if there are no edges, each vertex is its own component, and each new edge can only reduce the number of components by one). In this case we need V - 15 \le 3, so the maximum value of V is 18.
Also, please ask mathematics questions at the Mathematics reference desk. —Keenan Pepper 18:25, 1 December 2005 (UTC)

Accidental huffing[edit]

Today I took of water from a water fountain. After I had lowered my head towards the faucet, I could smell cleaner fumes. This upset me because I inhaled the fumes while being close to the source of the fumes. I'd like to know if this is the equivalent of huffing, because I'm scared of being brain damaged from the fumes.

Wikipedia does not generally give medical advice, so if you're really worried, go talk to your doctor. However, I suspect it was harmless. The effects of inhalants are usually acute rather than chronic, which means you get dizzy and even pass out before doing any permanent damage (unless it becomes a habit, of course). —Keenan Pepper 18:32, 1 December 2005 (UTC)
You may be suffering from hypochondria. I mean, c'mon, how long were you inhaling the fumes for? Nelson Ricardo 05:10, 2 December 2005 (UTC)
I think there are bigger problems if your water fountains are producing fumes. Water vapor is not a fume, nor ought it to have a smell. --YixilTesiphon 06:19, 2 December 2005 (UTC)
If you live anywhere near a sizeable built-up area you'll likely be inhaling exhaust fumes all the time (every breath you take, day and night). Living next to a busy road is like being a heavy smoker. I base this on tests done on children in Maastricht, not quite a big town. The traffic is nothing compared to that of a modern big city, let alone the ones in the US (eg LA) or third world countries. If you want to worry about something worry about that. DirkvdM 10:43, 2 December 2005 (UTC)
I once measured the carbon monoxide levels in central Zurich (Switzerland: population 366,145) to prove to my colleagues that they were not allowed to go downtown during working hours (and, incidentally, to prove that our lab met Swiss occupational health standards). Physchim62 (talk) 12:36, 4 December 2005 (UTC)

How Does An Alkaline Component of Laundry Detergnets and Cleaners Clean[edit]

How does an alkaline/base component of detergents and cleaners make a stain more soluble? In other words, how does it dissolve the stain?--Just Wondering

They clean as Surfactants by lowering the surface tension of water. Many alkaline substances also allow oils to be emulsified. Look at Alkali. Dominick (TALK) 19:04, 1 December 2005 (UTC)

This is sort of a trick question, because it really depends on the chemistry of the laundry detergent. Which brand are you using? --HappyCamper 03:29, 3 December 2005 (UTC)

Dear Happy Camper,

The laundry detergent used was good old fashioned Arm and Hammer Washing Soda.

A 1/2 tablespoon was put in 16 ounces of hot water with no other detergent (water is "soft") to remove an olive oil stain from cotton. A half an hour later, Voila,! No stain. How did it dissolve the stain.

Thanks for your help and ny others.

--Just Wondering

density of water[edit]

The density of water indeed. You might also want to see density of water and ice. --Borbrav 23:25, 1 December 2005 (UTC)

The density of water is the reference value for specific gravity; water is defined to have a specific gravity of 1. ᓛᖁ♀ 00:01, 2 December 2005 (UTC)

December 2[edit]

New Firefox version and its search engines[edit]

Hi,

For some reason the Wikipedia search engine that came with the previous version of Mozilla's Firefox browser (I'm using the most recent update) is now gone! Why is that, and does the company plan on bringing it back? I can't seem to find a place to ask at its website. --71.103.127.114 00:18, 2 December 2005 (UTC)

You can add the Wikipedia search engine plugin by clicking on the "Wikipedia" link on the following page: Search Engines. Be sure you have JavaScript enabled. You can also go to the same page by selecting "Add Engines..." from the drop-down list in the Firefox search box. --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 01:07, 2 December 2005 (UTC)
Holy crap, you're right! Thanks Mark. --YixilTesiphon

05:52, 2 December 2005 (UTC)

Hercules (constellation)[edit]

I am doing a science project and am having a hard time finding out why the "stars" were named after him.

Extracting information from the web (datamining)[edit]

How would I go about writing a program to extract data from a website (ie the sales rank of books on amazon.com)?

In principle, you'd write a program that simulated a browser connection to fetch information from a web site, perhaps using URLs you list in advance, or a web spidering system. Then you'd parse the HTML, assuming unchanging formats, to get the book info and rank. Then analysing it would be easy. In practice, if you plan to get all books rather than just a handful, this would hit Amazon's servers hard (perhaps as hard as thousands of customers). They are likely to have methods in place to detect this, assume they are under attack, and block your connection temporarily or permanently. Not recommended. Notinasnaid 09:41, 2 December 2005 (UTC)
Not sure what you mean, but HTTrack will let you download the entire Internet if you wish. Careful though, it's extremely powerful and you may get more than you bargained for. DirkvdM 10:49, 2 December 2005 (UTC)
Perl is good for problems that need a lot of text manipulation, as this does. The usual modules for making HTTP requests are comprised by the libwww-perl collection (LWP) [1], and there are a number of modules available for constructing requests (e.g. HTML::Form) and parsing HTML (HTML::Parser), which can be obtained from CPAN. ᓛᖁ♀ 10:51, 2 December 2005 (UTC)
It's also good to check if the website has an RSS feed available that you can easily extract data with; PHP has some good XML parsing functions you could use. Though if Amazon doesn't issue RSS i'd suggest the above. -Benbread 15:40, 2 December 2005 (UTC)
Actually, Amazon has an API to make this sort of thing much easier. I think it probably has sales rank. Superm401 | Talk 00:09, 3 December 2005 (UTC)

Can the use of mobile phones by pregnant woman, can harm the fetus?[edit]

Sir/Madam,

Iam Sudha, from Tamil Nadu,India.

If a pregnant women, who uses cell phones / mobile phones in her daily life, will the fetus (unborn baby)inside her will be affected if she continues using cell phones?

Can you please answer this question, as early as possible?

Regards Sudha --59.144.4.84 06:34, 2 December 2005 (UTC)

Sudha,
According to Mobile phone radiation and health, the risk of radiation from cell phone use is, as yet, unsubstantiated. However, as the article says "the World Health Organization has recommended that the precautionary principle could be voluntarily adopted in this case." So, I would say that the baby will be fine, provided the mother isn't always on the phone. I hope that helps to answer your question. --ParkerHiggins 07:04, 2 December 2005 (UTC)
  • Even if phones provide a health risk, the radiation it cause is only powerful enough to reach the woman's own brain which shouldn't have any direct influence on the fetus. Of course, effects on the mother will eventually affect the child psychologically if they turn out to be severe in the long run. I would recommend cutting down phone usage anyway. - Mgm|(talk) 09:40, 2 December 2005 (UTC)
Note that cellphones use electromagnetic radiation in the microwave range, so see the above discussion on the dangers (or lack thereof) of microwaves. —Keenan Pepper 18:38, 2 December 2005 (UTC)
I imagine that if there were any grave danger, a humongous increase in the number of birth defects would have been observed. It hasn't, so there's probably nothing wrong. --YixilTesiphon 00:12, 3 December 2005 (UTC)
Unless there's a problem passed to the next generation, like making the baby infertile. AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 16:35, 7 December 2005 (UTC)

Hot water[edit]

Does hot water contain more air than cold water?

No, the solubility of most gases (I want to say all gases, but there may be weird exceptions?...) decreases as temperature increases. A common example of this is carbonated water, which quickly goes flat on a hot day but keeps its carbonation for a long time when chilled. The reason for this is that, at a higher temperature, the gas particles move faster, and they can more easily escape from the surface of the solution (the vapor pressure is higher). So, the capacity of hot water to contain dissolved air is less than that of cold water. —Keenan Pepper 18:47, 2 December 2005 (UTC)
Which is why ice cubes made from boiled water (less air) are clearer. --hydnjo talk 20:31, 2 December 2005 (UTC)
Huh? Wouldn't additional air just dissolve as the ice cooled before freezing? Superm401 | Talk 00:11, 3 December 2005 (UTC)
Huh? indeed...Things can't dissolve in a solid. --YixilTesiphon 00:13, 3 December 2005 (UTC)
That's certainly not true. What do you think an alloy is? Superm401 | Talk 02:50, 3 December 2005 (UTC)
Bad phrasing on my part. Gasses are already dissolved (unless they are forming bubbles), so Suprm401's question doesn't make any sense. --YixilTesiphon 03:16, 3 December 2005 (UTC)
Huh? Let's take a step back and see:
Does hot water contain air more than cold water? The answer is no - this is because the solubility of air (ie, mostly nitrogen and oxygen) in water decreases as you increase the temperature. Keenan's example of soda is an excellent everyday example of this general observation - hot coca cola certainly doesn't have quite the fizz as a cold one! Ditto with beer.
As for the ice cubes - that's also the reason why boiled ice cubes look clearer - during the boiling process, most of the dissolved gasses escape. Hence, when you make ice cubes, no bubbles come out during the freezing process.
An alloy is an example of a solid solution. And yes, things can "dissolve" in a solid - however, it's a bit more of a subtle concept here. In this case, it depends on how you define "dissolve" - it may not necessarily mean "solvation". However, in certain fields of chemistry, it is desirable to restrict the definition to liquid solutions. I hope this clarifies things! --HappyCamper 03:23, 3 December 2005 (UTC)
Almost forgot: REgarding Superm401's question - yes, some air will redissolve back into the water when it cools, but the difference is that the rate of freezing is significantly higher than the rate at which the air dissolves. --HappyCamper 03:24, 3 December 2005 (UTC)
  • (exdenting for readability) Quiz question: Why are icicles clear? --hydnjo talk 03:38, 3 December 2005 (UTC)
They look clear because the freezing is incremental - but if you slice one, you will notice that there is a tendency for these bubbles to form in the center...so I guess they aren't really clear... --HappyCamper 03:40, 3 December 2005 (UTC)
Hmmm... one doesn't slice icicles, they're meant to be bitten. But I guess the result would be the same.  :-) --hydnjo talk 03:47, 3 December 2005 (UTC)
Is "icicle" generally used for the outdoors variety? So hydnjo, it's regular to get an icicle off a tree and eat it? Just curious. --Commander Keane 13:36, 3 December 2005 (UTC)
A common practice indeed for children in the northeast US anyway. Icicles from roofs in particular because they can get pretty big. --hydnjo talk 15:51, 3 December 2005 (UTC)
Ironically the picture at the bottom of Ice shows icicles formed on a roof in Australia, even though I live in Austrlaia (and have never seen snow/ice) and was unware of the use of icicles.--Commander Keane 17:56, 3 December 2005 (UTC)
I'm amazed! Snow and icicles in Australia! It's also interesting to see where the original question has taken us. --hydnjo talk 20:07, 3 December 2005 (UTC)

Lens & water[edit]

What happens when a liquid is inserted between a convex lens of focal length 20 cm and a plane mirror?plz give a detailed answer.

  • There's no general answer; it depends on the liquid (in particular its refractive index), what material the lens is made out of, the exact form of the lens (e.g. radius of curvature of each surface), and the distance between the lens and the mirror. Very roughly, adding the liquid will increase the optical path length between the lens and the mirror; but the exact effect will depend on the parameters above. --Bob Mellish 17:36, 2 December 2005 (UTC)
What do you mean by inserted? Is a tank of water placed between the lens and the mirror, or is the whole setup submerged in water? It makes a big difference. —Keenan Pepper 18:58, 2 December 2005 (UTC)
He means exactly what his teacher means, I suspect. (do your own homework)Superm401 | Talk 00:13, 3 December 2005 (UTC)
  • Do your own homework. It's a little offensive when you give exact numbers (thus indicating that this is a homework problem), and say "plz give a detailed answer." --YixilTesiphon 00:14, 3 December 2005 (UTC)
Hmm..."offensive" might be going a little bit over the top here I think. We need more background information about the question in order to help you better. Are you trying to find the effect of looking through the combination of lens-water-glass, as opposed to lens-air-glass? --HappyCamper 03:15, 3 December 2005 (UTC)
  • I think you guys are overthinking this one a little. It seems pretty straightforward to me.
Q. What happens when liquid is inserted between a convex lens and a plane mirror?
A. They get wet.

--DavidConrad 04:48, 7 December 2005 (UTC)

Order and names of the Periodic Table groups[edit]

Hey

There seems to be some dispute over the numbers of the groups in the Periodic Table - I live in the UK and i've always been taught there are groups 1-0/8 and the transition metals, with these being named because of the number of electrons in their outer shell. While wikipedia and other sources state there are 18 groups. I'm assuming that the 18 groups is correct, but where is there some difference of opinion among people?

Thanks :) -Benbread 15:35, 2 December 2005 (UTC)

Well, looking at periodic table I discovered, as I hoped, a section explaining this, albeit briefly. Basically, it seems the 1-8 plus transition metals scheme isn't entirely unambiguous, so is officially "deprecated" by the shadowy bodies that get to decide such things... - IMSoP 19:48, 2 December 2005 (UTC)
The naming isn't so much a "dispute" - it is more a reflection of our better understanding of chemistry from a quantum mechanical perspective. In particular, the IUPAC recommended the renaming a few years ago. The old grouping of systems is still useful for teaching purposes though. --HappyCamper 03:14, 3 December 2005 (UTC)

Illness[edit]

I am a 44 year female. I was diagnosed 3 years ago with RSD. Since then I have been diagnosed with ulner noropathy degenerative disc disease rhumatoid arthritis (severe 242) fibromyalgia have bulging disc in c4567 and sudden platelett count drop any ideas. Doctors here are stumped and can't seem to offer any new help. You may e-mail me at <email removed>.

  • Please read the instructions at the top of the page. Leaving your email address here will almost certainly get you loads of SPAM. - Mgm|(talk) 22:09, 2 December 2005 (UTC)

I am sorry for your combination of problems, which sounds like way more than any one person deserves. It is difficult to give you a simple answer to your question for many reasons:

  1. You may actually have a combination of problems and there is no unitary answer to be had. It is always more gratifying for both patient and doctor if a single disease can be recognized that explains all of a person's problems, but that is unfortunately the exception rather than the rule.
  2. But having said that, it is still likely that some of them are connected to each other, statistically if not causally. For example, a common cause of platelet drop (thrombocytopenia) can be a drug effect. Have you started anything new recently? You might want to check whether thrombocytopenia is listed as a side effect of any of the drugs you take. That doesn't prove a causal relationship, but it gives you some choices of what to do. Another cause of sudden platelet drop is a viral illness. The platelets usually return to normal within a couple of weeks. Some people can develop autoimmunity to their own platelets, especially when they have other autoimmune or inflammatory diseases like rheumatoid arthritis.
  3. If you have not asked your primary doctor for referral to a rheumatologist you might try that. They get lots of people referred for mysterious inflammatory conditions.

Good luck. alteripse 01:22, 3 December 2005 (UTC)

I need something back![edit]

You know when you type in the name of something and save it and it says 'do you want to replace the article of the same name', is there any way you can get the article you deleted back? Its very important and I couldn't possibly do it again. Thanks! ----XenoNeon 18:47, 2 December 2005 (UTC)

Are you referring to replacing a Wikipedia article? --Kainaw (talk) 19:25, 2 December 2005 (UTC)

No. A word document. Will it be anywhere in the computer after you deleted it?--XenoNeon 10:31, 3 December 2005 (UTC)

  • Doubtful. Try searching and see, maybe it's stored somewhere in temp files (remember to look in hidden and system files), but you're in bad straits here. --YixilTesiphon 13:34, 3 December 2005 (UTC)

Norton Antivirus 2004 offers a recycle bin which 'catches' and files deleted by whatever means (even non-manual) technically the file will probably still exist on your hard drive, but recovering it can be difficult and expensive, however, if the file is very important it is probably worth looking into professional help to recover it. The police use this method all the time, if a file is deleted it will still exist on your harddrive, however, the more times it is overwritten the harder and more expensive it is to recover it. - Unregisterd User 18:13 3 December 2005

A Question regarding paraffin...from e-mail address removed[edit]

Where can one purchase paraffin for arthritic joint therapy, and about how much does it cost?

Better not post your e-mail address here. You don't want to get even more spam, do you? —Ilmari Karonen (talk) 00:44, 3 December 2005 (UTC)

Go to google and then choose froogle. Enter parafin, and you get lots of choices: [2] alteripse 12:58, 3 December 2005 (UTC)

STI's and AIDS related[edit]

All I'm really asking is, how did all these dangerous epidermic happened? I mean, if we could go back in time, and say there are 100,000 males and females divided equally, all are all healthy individuals, how can STI and AIDS (or HIV) happened/started??

The answer is in evolution and mutation. Depending on how far back you want to go, we could assume bacteria, viruses, and protozoa exist (for simplicity we'll ignore multicellular organisms that live as parasites). Mutations in these agents can alter their virulence and transmission (medicine)--that is, the amount of damage they do and their ability to move from one host to another. As such, a virus or retrovirus that infects one type of organism could mutate to infect humans. This is believed to be the origin of the HIV strains that infect humans (see AIDS article) and is the crux of the recent global fear of an avian influenza pandemic.
The origins of infectious disease in general are older and less clear. But biological interactions are as old as life itself, and are seldom friendly (see food chain). Viruses may have arisen from a bit of host genome mutated to produce large amounts of a virion even at penalty to the host.
IlliniWikipedian 21:35, 2 December 2005 (UTC)
IlliniWikipedian is absolutely correct. There was likely no time in the past where the entire population was disease-free. Bacteria and viruses predate the origin of humans. Disease is ancient. Our primate ancestors had infections before we evolved. Furthermore, even suppose you were granted a wish and you wished all disease-causing entities to instantly die, it would not be the end of (infectious) disease. Vast niches would now be free, and it would only be a short time before some of the remaining, innocuous bacteria evolved to parasitize and cause disease in humans and other organisms. With regards specifically to HIV, the virus that causes AIDS: there is a related virus, a simian immunodeficiency virus, which causes an AIDS-like disease in monkeys. One strain of this was transmitted from chimpanzees (our closest relatives) to humans in sub-Saharan Africa and evolved into what we now call HIV-1, the predominant form of HIV. A different strain evolved into HIV-2, which still only exists primarily in Africa. — Knowledge Seeker 23:10, 2 December 2005 (UTC)
A problem here might be black and white thinking, the idea that certain organisms are purely bad. Where organisms live together they are likely to start interacting in some way. Sometimes this will result in one predating on the other, not with malicious intent, that's just the way things work. These we then call diseases when they're small (unless we want to consider ourselves a disease for the world's population of cows and such). At other times the interaction will be to the benefit of both, which we then call symbiosis. These interactions will always have happened, so there will always have been and always will be diseases (as already pointed out). DirkvdM 09:53, 4 December 2005 (UTC)

Help figuring out the components of a chemical reaction[edit]

Once I was flipping through a book of chemistry abstracts. I found one that described a reaction, the by products of which where C02 (sry don't know how to make subscript) and ethanol. There was some discussion following that it could be used to make alcoholic soda pop tablets.

(Reagents + Flavoring)Compressed into a tablet + Glass of Water = Adult Soda.

I saw this year ago, and have gone back to the science library and tried to find it, but to no avail.

Does anyone have any idea what would have been used?

Are you thinking of the powdered 'alcopop' beverages being sold in Europe? One of the brand names is Subyou [3], but I imagine that there are or will be others.
My understanding is that the powdered just-add-water beverage is based on ethanol encapsulation. Droplets of mixed water, ethanol, and starch (dextrin or the like—something water soluble and flavourless) are dried under controlled conditions. The starch traps most of the ethanol molecules but allows the smaller water molecules to escape. The 'dry' Subyou powder is about 30% ethanol by weight. Adding water redissolves the dextrin and releases the alcohol back into solution. There are several variations on this encapsulation scheme.
As YixilTesiphon mentions above, there are lots of chemical reactions that will generate CO2 when you add water. A powder containing a mixture of dry acid and dry carbonate or hydrogen carbonate (bicarbonate) compounds will certainly do it. TenOfAllTrades(talk) 01:16, 3 December 2005 (UTC)

I think the powdered alchopop thing is closer to what I was thinking of. It was years ago that I saw it, but in my memory the chems in it actually reacted in solution to produce the ethanol and the CO2. That may not have been hte case though.

Why bother adding water? Adult pop-rocks anyone? Dominick (TALK) 15:58, 3 December 2005 (UTC)

Well, whatever pop-rocks are made out of is probably polar, so ethanol could dissolve. Sounds like fun.--YixilTesiphon Say hello 16:03, 3 December 2005 (UTC)

Well - I think the only thing that'll put my obsessive mind to rest is finding the article. Thanks all.

Annealing Point[edit]

What is an annealing point? The glass article makes refernce to it but doesn't explain it. The article just saying that glass's annealing point is 600 C. -- User:King of Hearts 23:43, 2 December 2005 (UTC)

"Point" might be misleading, because it's fairly arbitrary: "When glass has been heated to a high enough temperature, it must be cooled by a controlled schedule of time and temperature or it will crack simply because of the strain inside the glass from the outside cooling faster than the inside. The sound of cracking glass in the waste buckets is common in glass studios. The thicker the glass, the longer the cooling time must be, days and weeks in the case of really thick castings. The annealing temperature is determined by slowly heating a long thin piece of glass supported at the ends until it just starts to sag (the sag temperature) and the annealing temperature is taken to be 50°C (90°F) below that, usually about 900F (480C). When scientific measurements are possible, the annealing point is a specific viscosity. "annealing point, AP—the temperature corresponding to a rate of elongation of 0.0136 cm/min when measured by ASTM Method C 336, Test for Annealing Point and Strain Point of Glass by Fiber Elongation. This test prescribes a rate of cooling of approximately 4 C/min with a fiber of approximately 0.065 cm in diameter, and a suspended load of 1000 g. The annealing point numerically approximates log = 13.0 poises, where internal stress is substantially relieved in a few minutes."" [4] - Nunh-huh 23:48, 2 December 2005 (UTC)

Our article is at Annealing. I've created a redirect from annealing point to it.-gadfium 01:22, 3 December 2005 (UTC)

December 3[edit]

Red Maple Tree[edit]

Hi, I'm helping my daugther with a tree project-Red Maple Tree and there are a few questions we needed to research to be able to do this project. First of all we had to pick a tree in our area to do the study on (Red Maple Tree). 1.How do you estimate the age of the tree by it's circumference? 2.The tree's habitat would be what (Where we live?)? The Red Maple's connection to technology and human wants and needs? 3.And very important the lif cycle of R.M.T.-this is a must have, all we could find are a basic tree cycle not necesary for R.M.T. And any other useful information that we could use in her report and Hypothesis-whether it blossoms flowers and what the seeds look like. We did find some general info, but not enough. Thank you so much for any information that you can provide. 12/2/05--71.66.123.248 posted 00:33, December 3 2005 (UTC)

Here are a couple of places to start where I found nice pictures of all the parts of red mapels: seeds, leaves, bark, etc. [5] [6] The habitat is where it is likely to be found in the wild, something like "northern temperate zone hardwood forest". Estimating the age from tree circumference can be done by finding a table of typical annual thickness increases for particular tree species [7] [8]. Or you can find a stump of a red maple, count the rings, and divide the radius by the number of rings to get the usual increase in diameter per year (remember diameter is twice radius). The circumference is about 3.14 x the diameter [9]. Or you could call your state forestry service and ask if they can tell you how to do it. Good luck. alteripse 01:09, 3 December 2005 (UTC)

I like "If you know when the tree was planted, you can easily and accurately determine its age." at [10]. The list members at [11] apparently believe width is not a very good measure of age. I'm inclined to think alteripse's suggestion of contacting the state forestry service might be better. Your IP indicates you live in Virginia, so the phone number of the Virginia Department of Forestry is 434.977.6555 . If you don't, you can look it up. Superm401 | Talk 02:45, 3 December 2005 (UTC)

Baby Tortoises[edit]

Esmé, a South African reader has sent the following question to the Wikimedia Help mailing list.

Please could you find out for me whether there is a specific term for a baby tortoise – so far the only term which has been presented is “baby tortoise” – surely there must be a more specific term?

I have advised her that it seems to be commonly used but I would be grateful if anyone could offer additional suggestions.

Thanks for any assistance you can give her.

Capitalistroadster 02:04, 3 December 2005 (UTC)

According to dictionary.com the baby turtle is called a hatchling. They don't have an entry for tortoises, but maybe that can be used for them as well? I expect it could be used for anything that hatches out of an egg. It does say what the collective noun for a group of tortoises is: a creep. I didn't know that, that's fun. -lethe talk 02:41, 3 December 2005 (UTC)

UHF Radio Frequencies[edit]

Cecily, an Australian Wikipedia user has asked on the Wikipedia help mailing list.

I am buying a uhf radio to use to communicate while skiing. Can you tell me if I am able to use a pair of uhf radios bought in australia overseas. I am particularly interested to know if I can use them in Poland.

Also what about Canada and the USA. I believe they will work but is it illegal to use one that is on australian frequencies.

If you could help me with Poland I would be most grateful.

Thanks so much in anticipation

Capitalistroadster 03:18, 3 December 2005 (UTC)

There are three zones for frequency allocations. In some regions those zones are divided across national borders. Generally, radios from one nation are only to be used there. An allocation in one nation for family talk UHF radios, could be used for Military communications elsewhere. Dominick (TALK) 15:54, 3 December 2005 (UTC)

So if I want to listen to military communications all I need to do is find out in which country those frequencies are used for domestic purposes and buy a radio there? Well, I suppose that if I were bent on that it might be easier to modify a radio to receive those frequencies. So the military won't be so stupid to use radio communication for 'classified' information. (Then again, ....) DirkvdM 09:59, 4 December 2005 (UTC)
No, but they may get pissed off if you start transmitting on their frequencies. If nothing else, it lowers their signal-to-noise ratio. —Ilmari Karonen (talk) 23:53, 6 December 2005 (UTC)

Salivary amalase?[edit]

Hello everyone! I am not sure if I recall this correctly, but I remember there is an enzyme in human saliva which helps with digesting glucose. The question I have is, if the time between chewing and swallowing is relatively short, what is the advantage of the body producing an enzyme which would only perform what seems to be a very very small part of digestion? --HappyCamper 03:35, 3 December 2005 (UTC)

Salivary amylase begins the digestion of starch to glucose. Even a small amount of glucose will begin to trigger insulin release so that the insulin is rising as food is being digested. Salivary amylase is not necessary to digest starch but it helps amplify the speed of metabolic response, as well as providing a small burst of glucose as you begin to eat. Finally, conversion of even a small amount of starch to glucose in the mouth enhances the taste of carbohydrates in our mouths. alteripse 03:51, 3 December 2005 (UTC)

Oh, I see...this sounds quite interesting...I didn't know that insulin is so sensitive to this. Would this be a reasonable example of a positive feedback system then? (From a controls perspective, "useful" positive feedback systems are almost unheard of, so it is excellent if this is considered one!) --HappyCamper 03:54, 3 December 2005 (UTC)
If you're looking for examples, oxytocin is a good one that occurs during labor. David D. (Talk) 03:58, 3 December 2005 (UTC)
I don't think salivary amylase is an example of positive feedback—where did you see the loop? Another biological example of positive feedback is during the menstrual cycle, such as the LH surge. — Knowledge Seeker 04:22, 3 December 2005 (UTC)
As I understand it, the contribution of salivary α-amylase (ptyalin) to overall starch hydrolysis is a relatively small fraction of overall carbyhydrate digestion; the lion's share of this task is performed by pancreatic amylase. Salivary amylase is rapidly inactivated by stomach acid, so its action is very brief. (By the way, the product of the action of salivary amylase on starch is maltose (a disaccharide), which would not be expected to directly stimulate insulin secretion). Salivary amylase is thought to take on a more important role in infancy, prior to the maturation of pancreatic exocrine function. It may also assume a bigger role in the adult in cases where pancreatic exocrine function is compromised. For a scholarly dissertation on the role of saliva in digestion, see: [http://tinyurl.com/7qkq6 Saliva and gastrointestinal functions of taste, mastication, swallowing and digestion] --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 05:30, 3 December 2005 (UTC)

I wouldn't characterize the insulin effect as positive feedback, but as early triggering or amplification of effect. Most food starch has a glycemic index almost as fast as glucose, indicating that hydrolysis of starch does not ordinarily contribute much to the time of absorption of many carbohydrates. There are a number of physiologic responses to the onset of eating that do not depend on waiting until substantial amounts of nutrients are already digested and absorbed and I suspect that the generation of a little glucose in the first minute of eating carbohydrates enhances some of metabolic and digestive responses as well as providing positive taste feedback to us. alteripse 12:54, 3 December 2005 (UTC)

Atoms.[edit]

Hey, this is a bit of a hard question, and I looked but couldn't find what I was looking for. What are the chemical compounds/atomical mass/ect. of Blood, Bone, Skin, and Nail? Any help would be just wonderful, thank you.

~Ryan.

The chemical composition by element has been available for decades and is easy to find: [12]. The atomic masses of the elements you can easily look up. There is no list of all the molecules comprising blood, blone, skin, and nail because new ones are being continually discovered and it would run to the thousands. Of the four tissues you mentioned, nails are the simplest and are comprised mainly of a protein called keratin and water molecules but even the nails contain small amounts of many other things. As far as skin goes, you might just as well ask for a listing of every molecule in a human body. alteripse 12:36, 3 December 2005 (UTC)

Nanobiotechnology[edit]

I have checked out the defination of nanobiotchnology from wikipedia, but I do not understand what it is saying. Can anyone please tell/explain to me what nanobiotechnology is really?

Thank you for your time.

Biotechnology on very small scales. --YixilTesiphon 13:32, 3 December 2005 (UTC)

For example the use of tiny biosensors that can be implanted under the skin and monitor things like blood glucose level. These use an enzyme to break down the glucose, a biological recognition layer to record the amounts of the products of the enzyme-substrate interaction, and a transducer to convert this into an electrical signal - very clever really! --Unregistered user 18:07 3 December 2005

Try Nanomedicine and the links in that article. --JWSchmidt 01:49, 4 December 2005 (UTC)

Library digitization[edit]

I am not sure that I understand the extent of this process, digitizing library collections. Is it simply creating a digital catalog, or the larger process of scanning documents and entering data?

Thanks so much for clarification.

  • Usually, it's scanning entire books. (I'm assuming you're referring to projects such as Google Book Search.) Some library whose name I can't remember in Egypt which has a large collection of rare Islamic texts recently scanned its entire collection. --YixilTesiphon 15:37, 3 December 2005 (UTC)

How long did people need to train with weights to lower their risk of coronary heart disease by 23%?[edit]

The question is like above. I searched but they couldnt find anything. So here goes, how long did people need to train with weights to lower their risk of coronary heart disease by 23%? A) 30 minutes b)55 mins c)80 minutes

Second one, After what age would people start losing muscle mass and strength caused by hormonal changes? A)30 b)40 c)50

I need it to be very accurate. BTW, thanks to everyone who helps me with the question. Many thanks ppl.

The precision of the desired answer tells me the answer was produced by a specific research study which you were supposed to read. How do you expect us to know which study that was? alteripse 18:25, 3 December 2005 (UTC)

  • Please do your own homework. General questions are cool and interesting. Specific ones taken off the worksheet due Monday aren't. --YixilTesiphon Say hello 18:32, 3 December 2005 (UTC)

Ubuntu live CD[edit]

I was trying to run the Ubuntu 5.10 live CD on my older PIII 800 Mhz 128 MB RAM Dell Inspiron 2500, but it is glacially slow. I'm assuming it's because 128 MB is not enough to run with all the default software the live cd has on it, but it's so slow (10 min to open a terminal window) that I can't even kill processes to free up memory. Is there an easy way to get the 5.10 live cd to use a file on the Windows partition as swap? Or do I just have to wait till I get a terminal window and set up a swapfile manually? (Which I'll have to go search to remind myself how to do that again.) Thanks - Taxman Talk 15:53, 3 December 2005 (UTC)

If you are using Windows XP, your windows partition is probably a [NTFS] partition, which Ubuntu/Linux cannot write to, only read it. If you have a FAT32 partition, I don't know, it might be possible. --WS 01:35, 5 December 2005 (UTC)
XP on a machine of those specs? Surely you jest. No it was ME, but I decided to just bite the bullet and install, and it worked out all for the better. Everything works amazingly well including the sound, power management, and wireless. I'm assuming the winmodem won't but oh well. It's still slow, so I'm planning to figure out how to slim it down a lot. I guess the first step would be a lighter window manager. I'll try to haunt some Ubuntu forums and learn the ropes, but if anyone has some info on good ways to slim down the ram requirements, I'd be interested. - Taxman Talk 14:23, 5 December 2005 (UTC)
It's difficult to configure Linux distros on Live CDs to access the hard disk for its swap files. Alternatively, you could use Damn Small Linux, which is only 50 MB in total, but fits a GUI and a surprising number of programs onto it. Surely 50 MB can fit into 128 MB of RAM. :) -- Daverocks 11:25, 5 December 2005 (UTC)
Well I had an older DSL disk, but I couldn't get it to boot properly, the 2.4 kernel would hang at some point. And with the compression those livecd's use 50 MB could be made to overwhelm 128 MB of RAM too :) - Taxman Talk 14:23, 5 December 2005 (UTC)

Climate change/global warming[edit]

What is the difference between global warming and climate change? Why did the media, which used to call it global warming, suddenly all start calling it climate change in unison? Who made them change? —Preceding unsigned comment added by Zzzzz (talkcontribs)

Global warming now has a paranoid stigma about it. It's merely a form of climate change; the other would be global cooling. --YixilTesiphon Say hello 16:06, 3 December 2005 (UTC)
Have a look at Global warming and Climate change; basically climate change describes the broader phenomenon which includes not only the current anthropgenic warming but other fluctuations such as past glaciation, etc. In addition, while warming is the major phenomenon, other things like altered rainfall regimes are also part of the picture. Guettarda 16:14, 3 December 2005 (UTC)
I'd say that last bit is probably the most important. Global warming is just one aspect and it's arguably not even the worst. And to a layman (especially one living in a moderate or cold climate) it might even sound like a good thing. Also, warming is the most likely effect. Other theories say we could be creating a new ice age. So calling it warming is a premature conclusion. That there will be a (major) climate change is however beyond doubt by now. Finally, with global warming you may still get local cooling. DirkvdM 10:07, 4 December 2005 (UTC)

Astronauts[edit]

Could kindly give the list of astronauts with their nationality, date and year who have landed on moon till 2005

  • Try searching NASA.gov or look up the Apollo missions here. --YixilTesiphon Say hello 18:20, 3 December 2005 (UTC)
  • All the astronauts who landed on the moon were Americans and did so between July 1969 and about 1974. alteripse 18:23, 3 December 2005 (UTC)
  • They were also all men, but for political purposes, our list of men who walked on the Moon has been moved to list of lunar astronauts. - Nunh-huh 18:37, 3 December 2005 (UTC)
    • Maybe the move was future-proofing, not political.--Commander Keane 22:01, 3 December 2005 (UTC)
      • As future-proofing, it hardly seems urgent. But that doesn't make it political either; I think we all agree that the list would include women if there were any, so the astronauts' sex is not relevant to their inclusion and doesn't need to be mentioned in the title. --Trovatore 22:57, 3 December 2005 (UTC)
    • The article includes the 12 Apollo astronauts who went near the moon but did not land as well as the 12 who did land, so in any case the "walked on the moon" part would be wrong. --Anon, 07:52 UTC, December 4, 2005
      • Nunh-huh is probably talking about this article. A little hard to find, because the link he gave was capitalized differently. It wasn't actually moved; it was redirected as a duplicate article. --Trovatore 08:00, 4 December 2005 (UTC)

Photon mass[edit]

No one's responded to this question on Talk:Photon, so I thought I'd ask here.

What is the status of the possibility that photons have nonzero rest mass? I remember seeing an old Scientific American article on it, showing how Maxwell's equations would have to change, among other things. As I understand it, current observations have put an upper bound on photon rest mass, but have not ruled out its existence. However, supposedly (I don't understand why), the discovery of a magnetic monopole would refute a nonzero rest mass for photons.

Anyone know anything about this? Have there been any theoretical or experimental developments that bear on the question since the article I remember (which probably would have been from the '70s or so)? --Trovatore 19:37, 3 December 2005 (UTC)

It is impossible, in some sense, to rule out the photon mass. But there are upper limits, set by experiments where we'd see the changes to Maxwell's equations if it had a mass above some value. At current, the recognized upper bound on the photon mass is
6 \times 10^{-17} eV [13]
Or about 0.0000000000000000001 times the mass of the electron, the lightest particle whose mass is known. I don't know anything about magnetic monopoles ruling out photon masses, but it is the sort of strange thing that finding magnetic monopoles would do—they also explain charge quantization, which I saw a proof of once but have since forgotten. Well, that's a start at least. -- SCZenz 19:46, 3 December 2005 (UTC)
Thanks. Might make an interesting note in Photon. --Trovatore 20:00, 3 December 2005 (UTC
  • The mass of photons is also often measured in terms of their energy in Mega-electronVolts (using the equation E=mc2) --YixilTesiphon Say hello 21:06, 3 December 2005 (UTC)
    • I specified in the question that I was asking about rest mass. You're talking about "relativistic mass". --Trovatore 21:09, 3 December 2005 (UTC)
    • Anyway, particle physicists don't refer to "photon mass" in this manner, since by E=mc² it would be completely redundant with the energy. Photons that are internal lines in Feynman diagrams can have non-zero mass (which can't be directly observed), but this is completely different. -- SCZenz 23:29, 3 December 2005 (UTC)

I don't think a monopole would refute a nonzero mass of the photon. It would probably depend on what kind of mass it was. For example, if the photon mass were due to a Higgs mechanism, monopoles would still be allowed. As for whether monopoles are allowed in the Proca equation, or if the mass is from a topological term, I'm not sure. -lethe talk 23:22, 3 December 2005 (UTC)

"Or about 0.0000000000000000001 times the mass of the electron, the lightest particle whose mass is known. I don't know anything about magnetic monopoles ruling out photon masses, but it is the sort of strange thing that finding magnetic monopoles would do—they also explain charge quantization, which I saw a proof of once but have since forgotten. Well, that's a start at least. -- SCZenz 19:46, 3 December 2005 (UTC)"

With that being said, photons would have to have infinite inertia, according to GR. Photons travel at C, and any mass would have infinite inertia at C. Do photons have infinite inertia?

If photons have positive rest mass, then they don't travel at c, but rather at different speeds depending on their energy. Since no such speed difference has ever been observed in vacuo (or at least I assume I'd have heard about it if it had been observed), the experimental error of these observations provides one way of putting an upper bound on their rest mass. --Trovatore 20:12, 6 December 2005 (UTC)
"A fast-moving object moving at near to the speed of light cannot be accelerated to, or faster than, the speed of light, regardless of how much energy we put into the system. As we apply a force, and hence do work on the object, its speed does not appear to increase by the amount specified by Ekinetic = 1/2 mv2. Instead, the energy provided to it is converted to mass, and its relativistic mass increases, in what is known as mass dilation. The relativistic mass of an object is expressed as a function of its relative speed." If a particle has any mass at all, at rest or in motion, it's inertia would be infinite if it were to travel at C. Photons do not have infinite inertia. You can keep reminding me of the bandaid Einstein used to keep GR together, but every attempt you make will only reinforce my argument against it. Rather than have me show you proof of photons not existing, why don't you offer definitive proof of photons existing. You cannot, without "funneling" light waves through a lens or aperture. It is because in every conceivable method of detecting a "photon" you must use a lens or aperture, which "focuses" the wave into a point, (be it in your eye, or in a camera). For this reason, and because it holds GR together, do people assume they exist. Kevin E Carman
"the mass of the electron, the lightest particle whose mass is known"
Just a note, but I believe the mass of a neutrino is far lighter than an electron - apparently about a 10 millionth the mass.
A note to any who would be confused (this means you K carmen): if photon's have a slight bit of mass, this means that they do not travel at "c" the "speed of light" (poorly named). We do not know for absolute certain whether "light" travels at the "speed of light". For this reason, "c" has become a word in itself to describe the universal speed maximum. Photons could conceivably have another 10billionth the mass of a neutrino - we wouldn't know because its too small to measure. The only reason we found neutrino's mass is because we found that in a super-nova event, the neutrino's reached us slower than the photons - meaning only that neutrinos are slower and thus have mass. Since theres nothing faster than photons - such a discovery simply won't happen. Fresheneesz 22:54, 7 April 2006 (UTC)

Running Processes[edit]

I run Windows XP, and I always have a lot of processes running. Right now, for example, I have 54, and I think that's low for today. Some I recognize (such as firefox.exe, or WINWORD.exe), but others I do not. Is there a program I can get, or a website to which I could refer, that would help me eliminate some of the extra ones I'm sure I'm running? Thanks! --ParkerHiggins 20:26, 3 December 2005 (UTC)

Just copy the process name into Google. You will quickly find many sites discussing each process. Windows XP has MANY programs that run in the background. It isn't like Windows 98 where you could safely kill everything except systray and explorer. As you find out what is running, you may find services running you don't want (like wireless network detector, pcmcia monitor, or firewire support). You can disable those services in the control panel somewhere. I don't remember exactly where. I gave up on Windows a couple years ago. --Kainaw (talk) 02:09, 4 December 2005 (UTC)
One place is in Control Panel > Administrative Tools > Services. In the right hand pane will be a list of services, their names, a long description, and whether they're started or not. George 03:32, 4 December 2005 (UTC)
To turn off running processes, go to "Run..." in the start menu. Then type in "msconfig". This should bring up a window titled "System Configuration Utility". Click on the "Startup" tab. There should be a list of processes there that you can check or uncheck to startup with windows. Hope that helps!--Dimblethum 05:12, 4 December 2005 (UTC)

DVD X[edit]

The Wikipedia Help mailing list received an inquiry from a reader as follows.

I bought DVD X copy program the last day they could sell them at Best Buy and when I went to activate it they said it was not longer allowed to activate the programs so I was out $119.00 and left with a program that I could not use I would really like to know if there is anything that I can do I guess this is what happens when you are computer stupid. My license ID:2641969 and I also have a pass word for it but need an activation key for it

If you can help this reader, it would be greatly appreciated. Capitalistroadster 22:59, 3 December 2005 (UTC)

From the DVD X website... "CAUTION: Authentic DVD X Copy software is no longer being sold anywhere. Many "closeout", clearance, auction and discount websites are selling fake DVD X Copy Software products and "patches" that are not authentic, CANNOT be activated or are cracked versions that DO NOT WORK properly and/or that contain spyware. Beware of any sites that continue to sell version 4.0.3.8 and that guarantee activation. DVD X Copy products purchased from these sites are not authentic, not eligible for support or updates and should be returned for a refund." --Kainaw (talk) 02:05, 4 December 2005 (UTC)

HFS command line utilities[edit]

I can't remember what are the command line utilities for changing the locked status of files under Mac OS X on an HFS plus volume. -lethe talk 23:04, 3 December 2005 (UTC)

Found the answer. /Developer/Tools/SetFile -lethe talk 01:47, 4 December 2005 (UTC)

December 4[edit]

penguins[edit]

When a penguin swims vs. walks, they have different heart rates due to a different intake of oxygen. When it swims, it needs more oxygen right? Is there any new information(from the past 3 years) on this topic, so i can base my essay on that? Thanks alot

Your assumption is most likely incorrect. While I am not a penguin expert, semi-aquatic animals have a slower heartrate in water than on land. A quick google search confirms the same for penguins [14]. The issue is oxygen use. Penguins don't want to consume more oxygen while swimming - they want to consume less. So, over time, penguins who have slower heartrates while swimming are able to swim longer and deeper and get more fish. --Kainaw (talk) 02:03, 4 December 2005 (UTC)
Though penguins aren't mammals, they might have something like the mammalian diving reflex. Is there an "avian diving reflex"? —Keenan Pepper 03:43, 4 December 2005 (UTC)
I was only assuming that penguins would have a similar reflex to mammals. As for the avian diving reflex, according to Ponganis (I don't know who he is), many avian species have diving aerobic activity that exceeds the calculated diving aerobic limit - requiring a slowed use of oxygen during diving. [15] --Kainaw (talk) 04:20, 4 December 2005 (UTC)
One comsideration. You probably mean oxygen consumption in time. But a swimming penguin is of course much faster than a walking one (what, twenty times faster or so? - 1 km/h vs 20 km/h). So the consumption per distance (ie the efficiency) will be much higher when swimming. DirkvdM 10:21, 4 December 2005 (UTC)
(Dirkvdm means consumption per distance will be less, and efficiency would be more, as it could be considered the reciprocal.) --YixilTesiphon Say hello 13:08, 4 December 2005 (UTC)
Oops. DirkvdM 10:22, 5 December 2005 (UTC)

One of your problems is that you haven't justified your assumption that penguins need more oxygen while swimming than while walking/waddling: if I were forced to walk like a penguin, then allowed to swim naturally, I think I would find the latter less tiring... Another, more complex point is to look at thermal regulation in penguins: in which environment is their overall heat loss the greatest? Finally, if you're still stuck, consider the oxygen equilibrium in large aquatic mammals (e.g., whales): this won't give you the answer, but it will at least convince you that the answer is out there somewhere! Physchim62 (talk) 13:15, 4 December 2005 (UTC)

Wiki administration[edit]

The Wikimedia help desk received the following question from Carey, a Wiki administrator.

I am wanting to do a little administration on the Wiki I installed internally but I didn't see anything concerning my idea. I want to limit a specific user or group to only be able to edit specific pages and their contents. Basically this user is going to be updating one specific page but I don't want that user to be able to edit any other pages.

I know there is a protect option to protect pages but my current Wiki has several thousand pages and protecting each one would be very time consuming not to mention not a suitable solution. If anyone knows of a way or if this isn't possible, I would like to know. Thanks in advance!

Thank you for any assistance you can give him. Capitalistroadster 02:21, 4 December 2005 (UTC)

Seems like MediaWiki-l would be the right place for this question (see Wikipedia:Mailing lists). -- Rick Block (talk) 17:40, 4 December 2005 (UTC)

Two dimensional molecule structure database[edit]

Can you guys help me find a good and reliable databases that features 2 dimensional molecular structures? An example of a 2 dimensional structure would be the image in the AMP article. I've found some databases on 3-dimensional structures of proteins [16], but am having a harder time finding something similar for 2 dimensional structures. KBi 03:31, 4 December 2005 (UTC)

  • The Linstrom, P.J.; Mallard, W.G. (eds.) NIST Chemistry WebBook, NIST Standard Reference Database Number 69. National Institute of Standards and Technology, Gaithersburg MD. http://webbook.nist.gov will probably not always have the structure you're looking for, but it is not bad. Otherwise there is ChemFinder, or PubMed, or several others depending on the compound you're looking for (Google as a last resort, but it can be useful for this type of problem)... A little bit more details about the type of compounds you're interested in would help to answer your question more specifically. Physchim62 (talk) 13:23, 4 December 2005 (UTC)

To calculate Heat dissipation[edit]

Could you please forward the formulae, which will be used to calculate Heat dissipation?

For example, if a equipment power consumption is 200 watts, how much will be heat dissipation value from that equipment? How to calculate?

Thanks in advance.

C.Ramesh

Sulaiman Petrotech ME FZE Innovative Engineering Solutions P.O.Box.: 18326. Jebel Ali. Dubai, U.A.E. Tel: 00971 4 8833525. Fax: 0097 1 4 8833626 Email: (Email removed)

Heat dissipation ≤ power consumption (in non-combustion situations). See First law of thermodynamics. Physchim62 (talk) 13:26, 4 December 2005 (UTC)
I suggest getting an engineering textbook. For example, Coulson & Richardson's Chemical Engineering, Volume 1: Fluid flow, Heat transfer and Mass transfer. There is no simple formula, except for heat transfer through radiation (Stefan-Boltzmann law). For non-radiative heat transfer (convection), you've get a lot more work to do. And the subject can't really be covered properly in anything smaller than a book. (And there are quite a few available) --BluePlatypus 23:52, 4 December 2005 (UTC)

If the system consumes 200W in power, unless it comes out in another form, almost all of it is heat. If a mythical board in a 10V system draws 20A, and has an output that sends a signal with 200Vrms and 1A almost no heat would be converted. ALmost all computers make heat from all the power they consume. Now a 200W powersupply does not always generate 200W, but has a maximum rating of 200W.Dominick (TALK) 15:51, 6 December 2005 (UTC)

Optics of reading a CD[edit]

I've been looking for information on how a CD is produced and read. In particular I am interested in the optics involved in reading the CD. Can anyone refer me to a source that discusses exactly what the interference is that reduces the light reflected at a pit-land boundary? Is it reflections from the two surfaces on either side of the boundary?

The article at http://en.wikipedia.org/wiki/Compact_disc contains a wealth of information, but there is one portion that bothers me. In the 4th paragraph under "Physical details" it is stated that the 125 nm pit depth is about one-sixth of 780 nm wavelength of the laser, and then "The sixth, 125 nm, (and not a quarter) of the wavelength was chosen to have a good trade-off between the push-pull radial tracking signal and the full-aperture read-out signal."

The relevant wavelength has to be that in the bottom polycarbonate layer. The pit depth would be one-fourth of the wavelength in the material for a refractive index of 1.56, close to what I find (1.55 to 1.58) listed in various places, so this is consistent. This raises a question about the rest of that sentance regarding tracking. I am seeking info on the subjest, and am not comfortable editing the article at this time. Apologies if I've violated any protocals here. --StanH 06:22, 4 December 2005 (UTC)

  • You're right. That change (from one quarter to one sixth) was made by user Dsc a short while ago. It appears to be purely wrong, perhaps he doesn't understand how wavelength is reduced in a medium, and assumed a reason for it. The rest of the info would seem to be suspect. --Bob Mellish 06:39, 4 December 2005 (UTC)

what is SIP Protocol[edit]

Dear Sir,

Could you plz let me know the meaning of the sentence"Voice Gateway on SIP Protocoland and all are line port"?

My question...........

1)what is SIP Protocol?How it works?How it is related with Voice Gateway? 2)What is Line Port?

  • SIP is Session Initiation Protocol. See the article for how it works.
  • On the back of your Voice over IP equipment, there should be two ports: LINE and PHONE. The line port should be connected to the phone line, and if you have a phone handset, that can be connected to the phone port.

--Canley 12:30, 4 December 2005 (UTC)

comperision[edit]

which are the coolest materials from the following list. Arrange in order.

No insulation wool felt cotton bubble wrap

Do your own homework Cool is a subjective term. Dominick (TALK) 12:22, 4 December 2005 (UTC)

I think bubble wrap is the coolest, because the bubbles are so fun to pop. —Keenan Pepper 16:03, 4 December 2005 (UTC)
Really? I say "No" is. That stuff is amazing - you can hardly feel it! --YixilTesiphon Say hello Consider my Wikiproject idea 16:49, 4 December 2005 (UTC)
Well I am not into "wrap". Dominick (TALK) 20:57, 4 December 2005 (UTC)
Here is my order, from worst to best: wrap, insulation, felt, cotton, wool, bubble, no. — Knowledge Seeker 02:39, 5 December 2005 (UTC)

(Header for the following question added)[edit]

how does the 25 elements of the body works? —Preceding unsigned comment added by 203.160.177.26 (talkcontribs)

sperm color[edit]

what color is sperm suppose to be? —Preceding unsigned comment added by 134.215.216.119 (talkcontribs)

Lol, interesting question. Usually it is white, but, from what I've heard, it can be yellowish, grayish, or brownish and still be fine.Dimblethum 04:46, 6 December 2005 (UTC)

science[edit]

Thomas Dolby!!!!! Dominick (TALK) 20:55, 4 December 2005 (UTC)

What mammals name's begin with x?[edit]

(no futher question)

Visiting Category:Mammals I came up with Xenarthra. Can't say I've ever seen one of those at the local park.--Commander Keane 19:06, 4 December 2005 (UTC)

Xenarthra are things like sloths and armadillos. --YixilTesiphon Say hello Consider my Wikiproject idea 21:30, 4 December 2005 (UTC)

Checking my OED, I find no mammals listed (other than blond humans, and the order Xenarthra mentioned above) beginning with X. Crypticfirefly 06:22, 7 December 2005 (UTC)

The Official Scrabble Player's Dictionary defines "xerus" as "an African ground squirrel". Rampart 00:40, 8 December 2005 (UTC)

Omega-3 fatty acids[edit]

What are the best sources of Omega-3 fatty acids?

oily fish like salmon is one, please sign your edits using four tilde(~) keys thanks 7121989 19:37, 4 December 2005 (UTC)
See Omega-3 fatty acid, and notice there is a fair amount of dispute over whether they are the greatest diet discovery since bread or relatively minor. Do some research and decide for yourself. - Taxman Talk 14:29, 5 December 2005 (UTC)

Gaia[edit]

  1. How much of the insolation is available energy for the biosphere?
  2. Should this be a proportion roughly equal to the energy conversion efficiency of chlorophyll, after accounting for land area?
    1. How efficient is chlorophyll, anyway?
  3. How much energy does the biosphere actually use?

ᓛᖁ♀ 20:44, 4 December 2005 (UTC)

The answer to point 3 is suggested by this UN report: "photosynthetic energy capture is estimated to be ten times that of global annual energy consumption". The latter was 3.8×1015 BTU in 1999 according to US DOE EIA. The UN report also calculates the efficiency of photosynthesis to be between 3% and 6%. --Heron 21:35, 4 December 2005 (UTC)
Interesting... oughtn't that be 3.8×1017 BTU, though? ᓛᖁ♀ 22:21, 4 December 2005 (UTC)

...This seems to show that the insolation, 1.74×1017 W, is four to five orders of magnitude greater than the biosphere can make use of (3.6-7.2×1012 W). Is that right? ᓛᖁ♀ 22:37, 4 December 2005 (UTC)

  1. Given that even the internal heat flux of the Earth is about an order of magnitude greater than the photosynthetic output, is the homeostasis Gaia hypothesis effectively impossible? ᓛᖁ♀ 23:13, 4 December 2005 (UTC)
Photosynthesis is not the only variable that is under the influence of living organisms. The composition of the atmosphere can be altered by living organisms, changing the ratio of energy entering and leaving the biosphere. --JWSchmidt 02:53, 5 December 2005 (UTC)
In fact, practically every characteristic of the Earth that I can think of, except its magnetism, can be altered by living organisms. --YixilTesiphon Say hello Consider my Wikiproject idea 03:48, 5 December 2005 (UTC)
Yes; very generally, I'm curious whether the relatively small amount of energy available to the biosphere is enough to control global energy variations to a significant degree. I suppose altering Earth's chemistry is probably the easiest method. ᓛᖁ♀ 04:27, 5 December 2005 (UTC)

Hot water freezes faster than cold?[edit]

I was watching a tv programme recently that performed an experiment where room temperature and near boiling water was placed in different ice cube trays, when placed in a freezer, x minutes later the hot water had frozen faster than the cold water. I've yet to try this so don't know if this is true, but if it is, why would this be the case? I can't think of any logical reason why this would happen, so i'm wondering if anyone else knows why? Thanks in advance 84.64.138.234 22:00, 4 December 2005 (UTC)

Too-wide tables in LaTeX[edit]

I've made a table in my LaTeX document that's narrower than the page, but wider than the page margins. LaTeX keeps aligning it with the left margin instead of centering it horizontally on the page. How can I get the table centered horizontally? I'm using the "tabular" environment at the moment. Thanks. -- Creidieki 23:49, 4 December 2005 (UTC)

Have you tried resizing the table to the margin size or less?
\resizebox{!}{17cm}{\begin{tabular} ... \end{tabular}}
--Canley 01:59, 5 December 2005 (UTC)

December 5[edit]

Tunneling[edit]

Dear Help Desk There is a new construction tunneling method is called New Austrian Tunneling method which we have read it from your website we are going to do a research program on this subject. This method is based on using a single lining of sprayed concrete using HPP fibres. Could you please advise me if there is some paper published about this method and how we can reach to any projects details using this method.

With Best regard Dr Hamid Abbasi (FRPRC)

  • Check the "Internal links" section of the article you're referring to. If there's nothing there, click on the "history" tab above the article, and scroll down to the creator of the article. Click on his/her name, then click on the "talk" tab above his userpage, then click on the "+" tab to leave him/her a message. --YixilTesiphon Say hello Consider my Wikiproject idea 22:26, 5 December 2005 (UTC)

Do bluetooth phones have SAR ratings?[edit]

Bluetooth techology sounds like a good way to increase distance between my head and the phone thereby making them safer choices.

Questions... What type of "waves" do the ear pieces give off? Is there a SAR for these waves, like there are for Dig/Analog phones What is considered an acceptable (i.e., safe) level of emission? Is bluetooth any safer than regular dig/analog cell phones from a emission stand point?

Thank you. Crillion 11:42, 5 December 2005 (UTC)

This article in BusinessWeek might be of interest. –Mysid 11:56, 5 December 2005 (UTC)

How to make a good flint for lighter?[edit]

A flint is composed of mischmetal, iron oxide and magnesium oxide. However, why is German flint much better than the Chinese flint? What are the differences? Does the purity of mischmetal make the difference? Or, the process of making the flint matters? Please kindly answer my questions, or kindly provide any references to me. Thank you very much.

While you are awaitng the definitive answer, take a look at Ferrocerium.--Commander Keane 16:30, 5 December 2005 (UTC)

Cost of leaving a computer monitor on[edit]

In a standard 9-5 work environment, what is the annual cost in wasted energy of leaving a PC monitor switched on overnight and at weekends, if the PC itself is switched off at those times (so the monitor will be in standby mode, not displaying anything)? Assume a fairly standard 15" CRT monitor, and UK energy prices. I'm trying to convince my work colleagues that this is worth bothering with (I work for a charity and saving money is important), but they all think that the cost is utterly negligible. I've tried Googling but couldn't find anything that quantified it in hard cash, though others may have more luck with different searches. --194.73.130.132 16:19, 5 December 2005 (UTC)

  • A search for "monitor power consumption" comes up with useful information. For example, this 15" IBM monitor eats 70 watts when its in regular use, and 10 watts in standby -- and 5 watts in "VESA off", which I imagine is how things would be with the computer turned all the way off. Using this UK power cost calculator: assume, then, 128 hours standby per week, ~512 hours standby per month will run you £0.14 -- about the equivalent of leaving a 100-watt lightbulb on for a day. Wasting any energy, of course, is not a good thing, but you won't be able to make a hard cash argument for it. --jpgordon∇∆∇∆ 16:39, 5 December 2005 (UTC)
  • And it seems to vary by monitor make/model/age; my Optiquest Q71 (a 17" CRT) claims less that 3 W consumption in standby/powersaving mode. The Energystar specs may prove helpful. --Bob Mellish 18:47, 5 December 2005 (UTC)
We have several posters at work that say that leaving a [CRT] monitor on overnight wastes enough energy to laser print 800 A4 pages. How accurate this is (or indeed how much energy it acutally is) I don't know, but I would suspect it is a useful rule of thumb. Thryduulf 01:51, 6 December 2005 (UTC)
I would expect a printer running for that long to use a lot more energy than a CRT monitor left on at night, but that might just be reflection of my ignorance. -04:27, 6 December 2005 (UTC)
5 Watt over 1 year is 5 x 24 x 365 = roughly 40 kWh. A 200 horsepower car engine delivers 147 kW. So the yearly power consumption of one monitor would let a car engine run for less than 20 minutes (is this correct?). Convincing one colleague who lives nearby, but commutes by car, to go to work by bicycle (or a more distant one by public transport) just one day per year would have a similar, if not bigger, effect. The goodie bit about this is that you can do it yourself (providing you don't already), so you don't need to convince anyone. And you could even do it every day. Wow, think of the effect that would have! And then you could also try to convince your colleagues to follow that example. In other words, consider barking up the right tree :) .
I would love to commute by public transport, but 2-3 hours on three busses with a 5-10 minute walk each end vs 50 mins-1 hour door to door by car is no contest unfortunately. Thryduulf 11:49, 6 December 2005 (UTC)
Gah, public transport must be awful where you live... checks userpage Oh. The UK. Right, just what I said... ;) Flag of Europe and Austria.svg ナイトスタリオン 12:08, 6 December 2005 (UTC)
Which makes me think. Shouldn't we have an article that lists the power consumption of different household items and such (and the power cost of making them). I bet the car would be at the top of the list in a very isolated position. I've searched for 'power consumption', which didn't give any results. And ecological footprint doesn't help either. DirkvdM 11:29, 6 December 2005 (UTC)
As long as the information is verifiable, I think that would make a good article and/or list. Thryduulf 11:49, 6 December 2005 (UTC)
Related issues
  • Repair Cost ... is there a relationship between how often you turn on & off the equipment, aggregate how long it is powered up, with its life span, After all, the equipment does not last forever, stuff wears out.
  • Human costs ... you show up for work, and power up your PC ... then you have to wait, and you are on the employee clock while you are waiting, unless your work load is such that you have something else to do while waiting.
I have metrics based on friends who manage networks and did unpublished tests.
  • Designate 100 PCs to be turned off outside work day.
  • Designate 100 to be left on 100% of the time,
  • Designate various sets of 10 where some parts of the hardware turned off outside the work day & other parts left on.
  • Designate 10 to be turned off during lunch hour.
  • Compare repair replacement hardware statistics by how the equipment is being treated, and include what kind of temperature extremes if the PC in an area without air conditioning or heat when no humans present.
What was found was that turning on & off at lunch time ... those machines had the MOST frequent trouble with stuff wearing out (electronic switches). The next MOST common problem was the stuff left turned on all the time. The equipment with the least trouble was that which was on during the work day, off during evenings, weekends, holidays.

AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 16:53, 7 December 2005 (UTC)

Weakened virus[edit]

The virus article states that vaccination is "the process of administering live, albeit weakened, microbes", though it also states that the cowpox virus is "a relatively benign virus that, in its weakened form, provides a degree of immunity to smallpox"

Firstly, obviously these sentences seem to contadict eachother. Is the virus weakened, or are the microbes containing them?

Secondly, how would one go about in weakening a virus? Is is irradiated, denaturated, shaken, ..? -- Ec5618 17:02, 5 December 2005 (UTC)

In the context of the source article, the term "microbe" refers to the microscopic causative disease agent-- in this case, the virus. It does not refer to some host organism (although there are bacteria, which are microbes, that are parasitized by viruses, which are also microbes). Smallpox vaccine is actually live vaccinia, or cowpox virus, and is not an attenuated virus. It is, however, sufficiently antigenically similar to smallpox that a cowpox infection (the intent of administering the vaccine) will confer protective immunity in a person who is immunologically competent. There are (other) vaccines that are live attenuated virus vaccines, such as the Sabin polio or the FluMist influenza vaccines, in which the virus is alive but modified so that it does not cause a full clinical infection.
Viruses are sometimes attenuated by culturing them in an environment that is different from the that found in the intended recipient of the vaccine. For example, a virus is cultured in a progressively colder environment, which selectively favors successive generations of the virus that are adapted to an environment that is below body temperature. These viruses would presumably find normal physiologic body temperature to be inhospitable, but would survive long enough to cause a mild infection and provoke an immune response. Denaturation of viruses usually results in a killed virus vaccine. --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 18:04, 5 December 2005 (UTC)
Vaccinia virus has diverged from cowpox virus; they are now distinct viruses. See this history which is cited at Cowpox and this analysis] which is cited at Vaccinia. --JWSchmidt 03:28, 6 December 2005 (UTC)

Xu bird[edit]

Is there such a bird in china as the Xu? I find mention of it in two articles by the same anonymous user (nullaby and orange flavor chicken) and I can't decide if he or she is just making it up. I've googled it as thoroughly as I can and find no mention of it, and while I know that isn't a substitute for actual research, it usually turns up something. So if there are any naturalists or bird afficionados out there I'd appreciate some information. thnx. Jasongetsdown 18:37, 5 December 2005 (UTC)

I'm not sure what bird the person was referring to. They mention the loon, which is lan ren in Chinese. Then, nightingale is mentioned, which is ye ying in Chinese. The first thing that comes to mind is the use of xu for fake. As such, xuguo means to make something up and xuwei means false. But, another use of xu is to indicate an animal is domesticated. But, it is commonly pronounced chu when used that way (the proper pronunciation is xu, but because it is often followed by sheng, it becomes hard to say xusheng). Finally, there is a surname Xu. Since the person capitalized Xu every time it was used, perhaps the family Xu has a special bird named after them. All in all, there is no bird named Xu in my dictionary. --Kainaw (talk) 01:00, 6 December 2005 (UTC)

Why are old things buried?[edit]

What is the mechanism by which all things get buried with time? Is it always slowly raining soil out of the sky? it seems that the older a thing is, the deeper it is buried. Why is this so?

Thanks

--216.130.131.66 19:34, 5 December 2005 (UTC)Frank Allen

                • @******.*** <email addressed removed>
It is not the case that old things are always buried. Some things are pushed to the surface over time. For example, I live on an old plantation where multiple civil war battles were fought. When I work in the yard, I still find old things being pushed up to the surface after every rain. I'm sure some things are pushed down as well. --Kainaw (talk) 20:36, 5 December 2005 (UTC)
I don't think Civil War-era artifacts are "old" in the context of the question. But sure, buried things sometimes get unburied. Then they usually don't last very long. I think that's part of the answer to the question: Things get either buried or destroyed, and we don't find the destroyed ones.
But no, it's not about "soil raining from the sky", mainly. Successive layers of sediment are generally added by water—either at the bottom of a body of water (since perhaps disappeared), or by flooding of rivers in an alluvial plain. Lots of different things can happen after that. With luck, maybe a geologist will come along and explain more specifically. --Trovatore 20:50, 5 December 2005 (UTC)

Gravity tends to push things downward, especially if they are relatively dense and the soil is moist, but more generally things tend to get buried as material accumulates on top of them. Dead leaves, soil that gets moved around, dust. Things tend to be exposed by erosion, but what erodes somewhere has to deposit somewhere else. Plant roots can bury something (imagine a tree growing up on top of an object) or expose them (imagine the tree falling over and the roots tearing the object out of the ground). Then add the magic factor of time... Guettarda 20:50, 5 December 2005 (UTC)

Erosion is the mechanism where broken down rock or soil moves around the place. Where I live, the local "hills" are weathering and eroding (ie moving) down towards the city. I guess in a long time the city will get buried. Basically the weathered rock, sediment, can be pushed around by wind or water (if you are under the ocean or a river) and will bury stuff. --Commander Keane 20:54, 5 December 2005 (UTC)
"Is it always slowly raining soil out of the sky?" It a way, yes. Plants take carbon dioxide from the atmosphere and use the carbon in it to make their bodies (wood, leaves, etc). When a plant dies it falls to the ground where it rots. The action of the rotting returns quite a lot of that carbon back to the atmosphere (as carbon dioxide again). But some gets buried by more dead plant material (leaf litter and stuff) before it has had a chance to fully decay. Buried, there's little oxygen; it keeps decaying, but without oxygen the bacteria that decay it can only work very slowly, and they never manage to finish the job. Over the years and centuries new plants grow and die and partially decay, and each summer adds another thin layer of material, piling up on what's underneath. So eventually things that once were on the surface are covered by metres of material. Peat is formed this way, and is often many meters thick. A similar process happens in the sea, with little plants and animals that live in the photic zone (near the surface, where there's lots of light) dying on the surface; their little bodies rain down on the sea floor (that's marine snow) and it piles up, year after year. Sometimes this piles up for tens of millions of years, and eventually becomes chalk. -- Finlay McWalter | Talk
Darn it, this guy got to it first. --YixilTesiphon Say hello Consider my Wikiproject idea 22:28, 5 December 2005 (UTC)
Which still leaves the question where the material comes from (the net result). I suppose part of it is the trees with deep roots that 'suck up' material from the ground and then dying, falling and depositing it on the ground (as Finlay pointed out), effectively turning the ground upside down. By the way, I believe Darwin investigated this too (measuring accumulation in his back yard), but I don't remember what he found. I vaguely remember it was something to do with snails. DirkvdM 12:40, 6 December 2005 (UTC)
The material comes from the atmosphere, like I said. It's rather counterintuitive, but trees and other plants are made of atoms they obtained from the atmosphere. If they got those atoms from the ground, trees would sit in little depressions - but they get it from the air, and trees sit on little bumps. This is why planting more trees will absorb atmospheric carbon dioxide (see Carbon_sink#Natural_sinks). -- Finlay McWalter | Talk 17:00, 7 December 2005 (UTC)


Areola changing size monthly?[edit]

Do the areola, lips, etc. change sizes periodically according to the menstrual cycle?

Interesting question. Though the article only mentions the breasts, I suspect premenstrual water retention affects other body parts as well. —Keenan Pepper 17:26, 6 December 2005 (UTC)

Why doesn't Oil and Water Mix?[edit]

I'm just wondering, why doesn't water and oil mix? Thanks, Dave

Water is a polar molecule - oil is not. Because this difference of this difference in the types of chemical charge, it is hard to form the weak bonds which allows anything to mix with another object (ie. form a solution) - without settling. -- Natalinasmpf 21:53, 5 December 2005 (UTC)

A little-known aspect of this is that the attraction between an oil molecule and a water molecule is actually stronger than the attraction between two oil molecules. The reason they don't mix is because the attraction between two water molecules is much stronger than either of those (because of hydrogen bonds). It's like the water molecules form a clique and although the oil molecules want to join, they can't because the water molecules don't think they're cool enough. (Silly little metaphor, but it helps. =P) ——Keenan Pepper 22:06, 5 December 2005 (UTC)

Interestingly, it's been found that when all dissolved air is removed from both liquids, they do mix. As far as I know there's no explanation for this yet. --YixilTesiphon Say hello Consider my Wikiproject idea 22:30, 5 December 2005 (UTC)

Maybe because removing the gases affects pressure, and would affect the self-ionization of water, or something. Do hydronium and hydroxide ions play a part in the solution formation? I would imagine. Of course this is only a wild guess. -- Natalinasmpf 22:46, 5 December 2005 (UTC)
Do you have a reference for this? —Keenan Pepper 23:59, 5 December 2005 (UTC)
Sadly I can't remember where I saw it. Maybe in Science News somewhere, but I can't remember the date, nor can I remember my pass to the site. --YixilTesiphon Say hello Consider my Wikiproject idea 01:04, 6 December 2005 (UTC)
The mixing should not be any surprise...in an oil and water mixture, there is always a slight amount of one substance dissolved in another - it just might not be an appreciable amount. --HappyCamper 01:18, 6 December 2005 (UTC)
It was complete, like salt and water.
In what proportions? Now this is very interesting. Perhaps the water had some sort of chemical in it, or perhaps it was not water at all, maybe hexane? --HappyCamper 02:07, 9 December 2005 (UTC)

December 6[edit]

Petroleum jelly[edit]

Why isn't petroleum jelly harmful for human use?

Everything is harmful to humans in excess. You can overdose on water and oxygen. Petroleum jelly has a long history of providing health benefits. It has also been consumed in small quantities by some who believe it is good for the digestive system. If taken in excess, it is harmful. --Kainaw (talk) 00:32, 6 December 2005 (UTC)
It doesn't react with most organic substances, and doesn't contain many aromatics. Dominick (TALK) 15:46, 6 December 2005 (UTC)

Starch and sugar[edit]

Why might a plant storage organ (such as a fruit or tuber) contain both starch and sugar? Thanks. --69.165.33.225 01:33, 6 December 2005 (UTC)

Do they seem mutually exclusive to you? Sorry not sure what you are getting at. alteripse 01:36, 6 December 2005 (UTC)

  • Are you asking why it might contain polysaccharides and monosaccharides? If so, then here is my answer. Sugars are usually stored as polysaccharides (why that is, I'm not exactly sure); glycogen is the main storage form in animals, and cellulose is for plants. To be used for an energy source the polysaccharide has to be broken down into a monosaccharide (usually glucose). So when a cellulose molecule in a plant is broken down, you could have both polysaccharides and monosaccharides at the same time.Dimblethum 05:02, 6 December 2005 (UTC)
      • That's only half the reason. The other reason is that glucose is quite small, so it can be easily lost by the plant to the environment, along with your oxygen and carbon dioxide. -- Natalinasmpf 22:07, 6 December 2005 (UTC)

AOL installation dies on me[edit]

What's up with these errors?? I have no idea why i'M getting them, AOL has always installed just fine in the past (AOL spyware not withstanding), and now everytime I start the process I get these..
&
File:AolBADw.jpg
followed by this one, then a crash
As an alternative, would anyone know where I can find a much older aol installation? online? something like AOL 5.0 or 6.0, so I don't have to put up with all the addweary goodness that is 9.0b-SE--Aolanonawanabe 23:49, 29 November 2005 (UTC)
  • bump* I forgot to mention I'm in a hurry--Aolanonawanabe 00:18, 30 November 2005 (UTC)
Well, I can't help with the error message, but there appears to be an AOL 5.0 version for download at this site. I've never used it before, but it looks to be fairly legitimate. --ParkerHiggins 01:06, 30 November 2005 (UTC)
  • I don't suppose you'd know off the top of your head, if AOL 5.0 had support for cable/DSL?--Aolanonawanabe 01:20, 30 November 2005 (UTC)
Well, a quick google determined that "AOL 5.0 has resident broadband support capability" (from this site with the annoying pop-up). I think that means you're a go, but I can't be sure. You can check on the article, if you're in doubt. --ParkerHiggins 01:27, 30 November 2005 (UTC)
Installation worked, this time crashed after installation finished , thanx anyway though--Aolanonawanabe 02:11, 30 November 2005 (UTC)
Might I ask why AOL? --frenchman113
Their bizaire fu#$%ed up proxy system does make for a nice bit of privacy/anonymity, even if it is just a side effect--Aolanonawanabe 01:55, 6 December 2005 (UTC)
I heard Tor does the same thing, though it's probably harder to install. --Unforgettableid | talk to me 05:52, 15 December 2005 (UTC)

Why, I say, why?[edit]

  • It still doesn't finish the installation, and at this point I'm more curious why, than anything else--Aolanonawanabe 01:55, 6 December 2005 (UTC)
  • Windows is a very broken thing hobbled by having to be backward compatible and a certain amount of poor design and failure to iron bugs out, so I'm surprised you would even ask why. On top of that, various installs and uninstalls of other software could easily leave your system in a broken state, that could interfere with the current install. The only solution to some windows failures is a clean install, but people will tell you that can be very risky as the distributor that installed in the first place had worked out all the driver issues etc, and probably had an image they ghosted onto the drive. You don't have that, so the reinstall could be risky. That said, I've used the OS reinstall disks that come with dells several times and they general work pretty well. So I'd say backup backup, get all your application install cd's and have a clean go at it. - Taxman Talk 13:59, 6 December 2005 (UTC)

Medical/psych question[edit]

Hey, this probably isn't the right place to ask this, but I have a question re mental health,fulfillment, and psychiatric meds.

I've got a great psychiatrist. He brought me back from a really bad place. I'm taking four different meds every day to keep things in the old brain operating normally, and as long as I do so I am able to deal with my feelings that life is utterly meaningless and lagerly devoid of pleasure and happiness.

That's what the meds are supposed to do - allow me to handle my feelings. Here's the thing - I'd like to enjoy life and be happy sometimes, not just not be overcome. I'm currently in therapy, and practicing cognitive behavior therapy. It is interesting but not efective in making me happy.

Is there any medicine that makes you happy? I have a _large_ family to support, and would rather not just exist as the food, shelter, and cash producing machine. I'd really like it if I could enjoy life as well.

What did your psychiatrist say when you asked him that same good question? alteripse 02:52, 6 December 2005 (UTC)

I wouldn't say there was. Besides, medicines that make you "feel" happy IMO would be kind of an empty, meaningless happiness....I am reminded of the "happiness" induced in Huxley's "Brave New World". Medication to relieve depression is one thing, but to seek happiness I would indulge in philosophy, metaphysics and Nicomachean Ethics, not medication. -- Natalinasmpf 04:51, 6 December 2005 (UTC)

I think there's a middle ground in there. I agree with Natalinasmpf that there are no psychiatric medications that make you happy, nor would you likely want them if there were. At the same time, many people, myself included, have better experiences with meds than something that merely allows you to function while still having depressive feelings. It's a fine line to draw, I know, but my experience is that the medicine didn't make me happy, it allowed me to be happy. On medication, I wasn't some unnaturally cheery person who was always happy regardless of the circumstances; but I was happy some of the time, more or less when you would expect a normal person to be, whereas when I had been depressed and not on any medication, I was constantly sad, even when I had no reason to be. If that's something you want to explore with your psychiatrist, talk to him/her about either increasing your dosage or switching medications. The danger is that the reaction to psychiatric medications varies greatly from person to person--what works wonders for one person is completely ineffective for another, and vice versa--and the only way of knowing what works best for you is experimentation. So if you do try switching medications, the danger is that you may give up even the functionality you've achieved so far. Whether that's a risk you're willing to take is between you and your psychiatrist. 12.223.56.106 09:26, 6 December 2005 (UTC)
  • Taking medication that makes you feel happy is just kidding yourself. Perhaps if the therapy works your psych will decide to lower the dosage somewhat. Still, the best way to feel happy is to do stuff you like to do with friends and family. - Mgm|(talk) 11:20, 6 December 2005 (UTC)
Meds, shcmeds. Philosophise. "Depressed" is a feeling; that "life is utterly meaningless and lagerly devoid of pleasure and happiness" is a thought, and it's obviously wrong. Think it through....
It can take a long time to develop an optimitic philosophy that can stand up to negative influences, and a longer time to translate that philosophy into positive emotions.... start by accepting that your happiness is your number one priority, more important even than "the truth". Exclude negative influences from your life (a friend of mine now refuses to watch the news; he's ill informed, but it doesn't matter, and people like him a lot more....) Learn to nip all negative emotions in the bud.... they're highly addictive, and entirely useless. TheMadBaron 02:02, 10 December 2005 (UTC)

This might sound a bit trite but I'm happy if I wake up in the morning. My life is hard. My work is hard. I also feel that I am just a machine to produce money, food, shelter, for a bunch of leeches but when I look back to my dad I can see that he too must have felt the same. In time I have grown to understand that I was not as considerate as I could have been when I was young. That keeps my hopes up as regards my own little leeches in that over time they will be more considerate. In the mean time I take pleasure in the little things and those odd moments when I get to watch the sun going down. Take pleasure in the little things and the big problems are easier to handle.--Eye 23:16, 10 December 2005 (UTC)

Prolog[edit]

Is it possible to implement an equality check for "arrays" in Prolog? I am running into a problem where my particular version of Prolog is comparing memory addresses instead of the actual array contents in the recursive check. Any tips? --HappyCamper 03:11, 6 December 2005 (UTC)

If you're using "A == B" (A identical to B) you might try "A ?= B" (A unifiable to B). If you're actually using lists, and they're fully instantiated (no uninstantiated elements), "A ?= B" should tell you whether the lists contain the same elements (recursively, all the way down to atoms) in a single expression. -- Rick Block (talk) 03:24, 6 December 2005 (UTC)
Hmm...let me try that. I'm using SWI prolog if that makes a difference... --HappyCamper 03:27, 6 December 2005 (UTC)

Active polymer material which acts as an antiback agent in textile washing industry[edit]

Will pressure different inside and outside a building?[edit]

Will the air pressure different inside and outside a building?For a building near the sea,will the air pressure different too?

For the most part, no, there will be no difference. Buildings are not airtight, and even if they were, the pressure would rapidly equalize as soon as anyone opened a door. One exception to the general rule would be inflatable domed sports stadiums, such as the RCA Dome, where a roof of flexible fabric is held up by air pressuree. In these, the pressure is retained while people enter and exit via revolving doors. There are also conventional doors which can be used as emergency exits, but the pressure difference does create a stiff breeze if these are opened. Chuck 09:09, 6 December 2005 (UTC)
Skyscrapers also seem to have a stiff breeze when doors are open; perhaps they have trouble equalizing pressure because the external pressure is different between the top and bottom? -- SCZenz 09:15, 6 December 2005 (UTC)
It shouldn't be because of the pressure difference between top and bottom, either externally or internally. The difference in pressure due to altitude is an effect of gravity, and it would have the same effect both inside and outside the building. (That is, the external pressure at the top of the building will be less than the external pressure at the bottom, but at the same time the internal pressure at the top will be less than the internal pressure at the bottom.) I'm just guessing here, but I suspect that skyscrapers, while not perfectly airtight, have few enough spaces for gas to escape that it is possible for a pressure differential to build up, just as a result of ventilation, possibly with effects due to heating or cooling the air inside the building too. Note that skyscrapers also generally don't have windows that can be opened, limiting the ways in which the external and internal pressures can equalize. Chuck 09:32, 6 December 2005 (UTC)
  • One would think the answer is yes, in certian situations, this is after all the cause of most tornado damage--Aolanonawanabe 11:42, 6 December 2005 (UTC)
No, tornado damage is caused by the wind. It was at one time thought that when a tornado was approaching, one should open a window to "equalize the pressure," it's now known that this is unneccessary, and in fact it is strongly recommended that one not open a window. See here and here for examples. Chuck 13:46, 6 December 2005 (UTC)
  • All that says is that openning a window is pointless and would just scatter broken glass anywhere, it doesn't say anything about there not being a preasure difference, not to mention wind is a preasure difference--Aolanonawanabe 15:43, 6 December 2005 (UTC)
Air flow, such as wind, causes pressure to drop (this principle is also used in wings). So if a wind starts blowing, there will be a difference in air pressure, causing air to flow out at a rate dependent on the size (and location?) of apertures. And when, after satbilising, the wind (suddenly) drops, there will again be a pressure difference. About the location of the apertures. Suppose they are all at the windward side. Then I suppose air will get blown in, causing air pressure inside to actually increase despite the decreased outside pressure. DirkvdM 14:25, 6 December 2005 (UTC)
That is very correct. A house cannot adjust pressure immediately. Wind also creates lift on the roof. Combined, many roofs give way and blow down the road. --Kainaw (talk) 16:57, 6 December 2005 (UTC)
If your building is large enough then you may notice a Helmholtz Resonator. If this is the case then pressure in the building will periodically move up and down. For the Helmholtz Resonation to work, you need a dominant opening (ie a big door) and for the rest of the building to be virtually sealed (note: a shopping centre provides perfect conditions). When wind hits the opening it goes into into the building and sqeezes/compressses the air inside - increasing the pressure. The air then expands back, and the pressure drops. The process repeats itself.
Helmholtz resonation occurred at a local shopping centre. When it was raining it was noticed that the rain was getting "sucked" about 10 metres into the building - and stores were getting soaked. In the neighbouring post office the rain was only getting sucked in a couple of meters - the large, sealed nature of the shopping centre was allowing resonation which periodically sucked in air (and rain), and peridocially forced out air (but not the rain, which was saturating the store displays). The solution was to reduce the size of the dominant opening, with a glass wall replacing to old big door, and a side door installed. This is illustrated below, not to scale.
                     _______________ 
                    |               |
                    |               |
                    |               |
                    |               | 
                    |               |
                    |____        ___|
new door =>               /_______|
--Commander Keane 21:52, 6 December 2005 (UTC)
It is worth noting that the barometer is one of the few weather data recording instruments that meteorologists prefer to have indoors. Obviously instruments such as thermometers need to be outdoors, but for one that would get the same reading both indoors and outdoors, why expose the instrument (or, for that matter, the human observer) to the elements? EWS23 | (Leave me a message!) 03:59, 10 December 2005 (UTC)

Kerosene and burning it.[edit]

I have searched everywhere but was not able to find the answer I was looking for. If I pour kerosene (ordinary kerosene) into a cup (a standard cup in which you drink tea) and then bring a lighted matchstick over it, will it burn? I am sure it will not, but my friends at work say it will and have bet me one cup of tea. I also remember doing this exact thing when I was a young kid and it did not.

Various web pages, such as this one, give the flash point of kerosene as 110° Fahrenheit (which is 43° Celsius) or somewhat higher. In order to start it burning you would have to warm some of the kerosene to at least that temperature. A match held very close to the liquid might very well do it: after all, people light kerosene lamps easily enough. But a match held "over" the cup at a short distance might not (even though a more dangerous fuel like gasoline would ignite). I would not want to speculate as to how close you bring it in safety. Indeed, I'd say "don't try this at home, kids." --Anonymous, oh my look at the time, 10:10 UTC, December 6, 2005
I think the vapour pressure of kerosene at room temperature in low enough that it is actually pretty hard to light. I have seen someone demonstrate this by dropping a lit match into a container of kero. The match went out. Kero lamps use presure or wicks to help vaporise the kerosene before burning it. --Martyman-(talk) 11:03, 6 December 2005 (UTC)
Keep in mind that the liquid does not burn. The vapor/fumes/gasses burn. In a lanp, you light the wick, which heats the kerosene that has crept up the wick. At first, you are burning cotton (or something similar). As the heat builds up, you begin burning fuel instead. On a similar topic, I did an experiment with lighting a milk carton full of gas and one with just a little gas in the bottom. The full one caught on fire and made a mess. The empty one exploded and left a hole in the ground. Once again, the reason was that the fumes burn - not the liquid. So, going back to the original question, holding a match over the liquid to try and get it to start evaporating should get a flame started, assuming the match doesn't burn your fingers first. --Kainaw (talk) 16:52, 6 December 2005 (UTC)
No, the kerosene will not light. Also, at normal atmospheric temps and pressures one match will not be sufficient to heat the kerosene to a point where the vapours ignite and the flame is self-sustaining. If you include some kind of wick (even a rag will do) then its quite easy to ignite kerosene. Otherwise it is actually fairly difficult and you need to compress/heat it quite a bit. This makes kerosene much safer and is why it is preferred to gasoline in many applications. So go collect your cup of tea. If your friends don't believe you, go buy a bit of diesel (chemically almost identical to kerosene) and show them. I promise you it won't ignite. -User:Lommer | talk 02:46, 15 December 2005 (UTC)

"How can i make women attracted to me"?[edit]

Moved to Wikipedia:How can I make women attracted to me?, as HappyCamper suggested moving to Main, yet I don't have time to de-discussionify, yet it would be a shame if this discussion was moved to the archives. :) --Unforgettableid | talk to me 05:59, 15 December 2005 (UTC)

smallest vertebrate of the world[edit]

The shrew article notes that the Pygmy White-toothed Shrew is the smallest living mammal. It weighs 2 grams. I would assume the smallest vertebrate would be some kind of tiny fish. Jasongetsdown 17:25, 6 December 2005 (UTC)

Could it be Schindleria brevipinguis, the stout infantfish? —Keenan Pepper 17:33, 6 December 2005 (UTC)

Face recognition[edit]

How far away are we from the face recognition technology of "The Island"? --Phil 1970 17:36, 6 December 2005 (UTC)

I would say we are still very far. Computer vision is widely regarded as an AI-complete problem, and right now I doubt there's a program that can even reliably tell if a face is frowning or smiling (anyone want to contradict that?), much less tell whether two images are of the same person. —Keenan Pepper 17:47, 6 December 2005 (UTC)
I think face recognition was implemented commercially at many major american events after September 11. I believe the first case I can think of was at the superbowl. I seem to recall there is a proposal to implement it as part of the London Tube security upgrades. See: Facial recognition system. Of course the reliabilty of these systems is questionable. --Martyman-(talk) 21:11, 6 December 2005 (UTC)
Face recognition is a lot better than you'd think. Now the cloning technologies in The Island? Bullshit. --YixilTesiphon Say hello Consider my Wikiproject idea 00:46, 7 December 2005 (UTC)
There must be differenced between Computer vision (which allow computers to "understand" image content or content of multidimensional data in general) and a Facial recognition system (that works by comparing selected facial features in the live image and a facial database) which is a lot easier to realise. --helohe (talk) 14:38, 11 December 2005 (UTC)

Microsoft word[edit]

I do not have Mkicrosoft word on my computer and I wish to have it as what I currently have isn't getting me anywhere. Does anyone know any sites that you can download Microsoft Word, not some update, on to their computer. I really need it. Thanks!--XenoNeon 17:59, 6 December 2005 (UTC)

It's proprietary software that costs money. You have to go to the store and buy it in a box, or get it illegally from a pirate. —Keenan Pepper 18:01, 6 December 2005 (UTC)
Silly me, I forgot to suggest OpenOffice.org or AbiWord instead. =P —Keenan Pepper 18:02, 6 December 2005 (UTC)

Thank you very much. You're a lifesaver! You deserve a reward. Honestly!--XenoNeon 18:37, 6 December 2005 (UTC)

Hm, I use OpenOffice; didn't know about AbiWord. Anyone care to compare the two? Does AW have sufficient advantages over OO to make it worth my time to download it, set it up and try it out? --Trovatore 19:33, 6 December 2005 (UTC)
Abiword is merely a word processor - OpenOffice.org also contains functions for spreadsheets (like Excel), presentations (like PowerPoint), databases (like Access), among others. What will work for you depends on what you want - sometimes the multi-tool is ideal, sometimes you want something specialized. Just download and try it to check if it suits you - it won't cost you very much unless you're on dialup or pay per megabyte downloaded. TERdON 20:41, 6 December 2005 (UTC)
I use OpenOffice 2.0 as well. Love it. --YixilTesiphon Say hello Consider my Wikiproject idea 03:10, 7 December 2005 (UTC)

There's also a free Microsoft Word Viewer available for download from Microsoft.[17] It won't let you edit documents, but it's a convenient little tool for reading them. —Ilmari Karonen (talk) 23:32, 6 December 2005 (UTC)

You can also download trial versions which work for 60 days from Microsoft's website - the UK site at least. --Canley 05:34, 8 December 2005 (UTC)

How does Arm and Hammer Washing Soda Dissolve an Olive Oil Stain (Just it and Hot Water)[edit]

Dear Happy Camper,

I wasn't sure how to answer your response to my December 1, 2005 , 1.15 question, so I edited it there and wrote this as a "new" question to a question. If wrong, I am sorry since I am new to this.

The laundry detergent used was good old fashioned Arm and Hammer Washing Soda.

A 1/2 tablespoon was put in 16 ounces of hot water with no other detergent (water is "soft") to remove an olive oil stain from cotton. A half an hour later, Voila,! No stain. How did it dissolve the stain.

Thanks for your help and any others.

--Just Wondering

Look at emulsify and detergent. A base, that is a high pH chemical, can cause oils to dissolve in water. Dominick (TALK) 19:28, 6 December 2005 (UTC)

Hi again! Sorry, I almost missed your question! I have been dabbling around different places on Wikipedia lately. No need for apologies - I'm glad to see you're around and enjoying the reference desk :-) Regarding your question, this is what my hunch is regarding what is happening -- Washing soda is really just sodium carbonate. It acts as a water softener. It also does a few other things too. When it dissolves in water, you get some carbonate ions (CO32-) through this process:
Na2CO3 -> 2Na+ + CO32- -- The sodium ions doesn't really do much. In this case, they are known as spectator ions. What happens to the carbonate ion? It reacts with the water in an equilibrium:
CO32- + H2O <-> HCO3- + OH-.
What does the hydroxide (OH-) ion do? It encourages the trans fatty acids in olive oil to dissociate. Let's represent this trans fatty acid with this:
/\/\/\/\/\/\COOH
and what happens is this:
/\/\/\/\/\/\COOH + OH- -> /\/\/\/\/\/\COO- + H2O
What is /\/\/\/\/\/\COO- ? Not exactly soap, but something that acts pretty much like soap.
In other words, the washing soda is slowly converting the olive oil into something that acts like soap, and this helps remove more olive oil from the shirt. This process happens continually until the entire stain is removed, or the washing soda is used up. The result is an emulsion of oil in water, stabilized somewhat by the washing soda. I must be a bit honest here - I'd be interested to test this out myself under more controlled conditions, as I think most of the work is actually being done by the hot water, and not so much the soda. The preference for the olive oil to stick to the cotton seems marginal to me based on just chemical structure alone. Finally, why is washing soda a good choice for things this? For one thing, it is a rather gentle compound - you would not want to wash cotton in a strong base, say something like lye - otherwise, the shirt might get damaged! I hope this helps, but if not, I hope it encourages you to learn a little bit more about the fascinating world of chemistry! --HappyCamper 01:38, 13 December 2005 (UTC)

Regarding nuclear decay:[edit]

In types of decay which emit neutrinos or antineutrinos (beta decay, I believe), where's the neutrino come from, and why does it get emitted?

Also, with types which involve a neutron becoming a proton (such as in beta decay) or vice versa, what causes the change? I never was able to get an answer to these in any of my science classes. --Mr. Fluffles 20:24, 6 December 2005 (UTC)

One reason, I believe, is that it's necessary for spin to be conserved. The neutron, proton, and electron each have spin 1/2, meaning their spin in a given direction can have a value of +1/2 or -1/2. If you only had n -> p+ + e-, you wouldn't be able to conserve spin; the left half of the equation would have a spin of either +1/2 or -1/2, while the right half would have a total spin of 1, 0, or -1. Photons have spin 1, so throwing one of those in wouldn't help. The electron antineutrino produced in the decay of a free neutron also has spin 1/2, so once that's added to the equation, spin can be conserved.
As for the question of why a free neutron decays, I'd say that If it can happen, it will. The neutron is more massive than the proton, electron, and antineutrino combined, so it gives off the excess mass as energy--in the form of a photon--when it decays. For contrast, compare the deuteron, an atomic nucleus consisting of one proton and one neutron. Because of the binding energy between the two, the deuteron has less mass than its possible decay products of two protons, an electron, and an antineutrino, so the deuteron doesn't break up unless you throw some energy at it. Chuck 22:29, 6 December 2005 (UTC)
Thanks. --Mr. Fluffles 01:23, 7 December 2005 (UTC)
Also, lepton number must be conserved. In β decay, you start with a neutron: there are no leptons, so the lepton number is zero. Afterwards, you end up with a proton (lepton number zero), electron (lepton number 1), and an electron antineutrino (lepton number -1); this adds to zero. The antineutrino also carries away some of the momentum and energy of the reaction; the masses and momenta of the products are insufficient to account for the mass and momentum of the reactant neutron. Free neutrons are inherently unstable and will undergo decay by this process. The "converse" reaction, a proton being converted into a neutron with emission of a positron and an electron neutrino, is much more difficult; since the neutron has more mass than the proton, energy must be supplied to drive this reaction. A variant of this reaction occurs in the proton-proton chain reaction, one of the fundamental nuclear processes of our sun. According to that article, a proton waits an average of one billion years before being converted into a neutron (and combining with another proton to form a deuteron. Hope this helps (and hope I'm on the right track)! — Knowledge Seeker 05:01, 7 December 2005 (UTC)

Is there any other software like AOL?[edit]

That would allow for similarly anonymous shifts from server to server? Or is AOL a uniquely f#$%^&d up entity?--Aolanonawanabe 21:28, 6 December 2005 (UTC)

Hey, this is Wikipedia. There's no need for censorship here. :p But of course, moderation of language is good. -- Natalinasmpf 22:01, 6 December 2005 (UTC)

  • To be perfectly honest, I was actually going for the humor angle there--Aolanonawanabe 22:02, 6 December 2005 (UTC)
If you want real anonymity, use Tor (anonymity network). AOL's shifting doesn't really give you much anonymity - we see the same AOL IP address vandalise the same article for days sometimes (I guess others share that address too, and the vandal sometimes gets other addresses too, but by no means is it a "new IP guaranteed for each transation". -- Finlay McWalter | Talk 01:36, 7 December 2005 (UTC)
Noting, of course, that Wikipedia blocks editing from the Tor proxies precisely because there is no way to tie an individual to his anonymous edits. (There's no way for us to deal with vandals using those proxies, so we block them from editing.) TenOfAllTrades(talk) 04:55, 7 December 2005 (UTC)
  • It isn't what you asked but I wonder if what you meant was the way in which AOL users typically have an IP address that changes? If so, the answer is no: AOL are following the standard procedure for ISPs with dial-up users. A few ISPs reserve IP addresses for dial-up users, but this is felt to be a waste of scare resources. Notinasnaid 21:04, 7 December 2005 (UTC)
  • I heard that public library staff generally do not keep logs of who does what, in order to preserve library patrons' right to privacy. YMMV. --Unforgettableid | talk to me 05:54, 15 December 2005 (UTC)

forces[edit]

December 7[edit]

Nucleotides[edit]

What type of bond connects nucleotides? Thanks. --Sango123 (talk) 04:36, 7 December 2005 (UTC)

It depends; was your assignment more specific? :D See our article on DNA for details—bonds joining nucleotides along one strand of DNA are of one type, and the bonds that join two DNA strands together are of another. TenOfAllTrades(talk) 04:51, 7 December 2005 (UTC)
You're most likely looking for hydrogen bonding. --YixilTesiphon Say hello Consider my Wikiproject idea 05:07, 7 December 2005 (UTC)

US uranium enrichment[edit]

Yvonne, a reader, has sent the following question to the email help desk.

"Supposedly there is only one company in the USA that is allowed to enrich uranium and can you tell me their name? They are a publicly traded company. I am doing stock research. Thank you and best regards."

Thanks for any assistance you can give her. Capitalistroadster 04:57, 7 December 2005 (UTC)

United States Enrichment Corporation, which was privatized in the 1990's. At the moment, they still use the high-cost gaseous diffusion process for isotope seperation, but they are apparently planning to build a centrifuge plant. See their website for details. I don't know whether there's any rule that says other companies couldn't get a license to start up an enrichment plant, but there would be very, very high regulatory hurdles to climb. --Robert Merkel 05:08, 7 December 2005 (UTC)

Spell checking[edit]

Which algorithms are most commonly used by commercial spell checkers, and what does aspell use? ᓛᖁ♀ 05:41, 7 December 2005 (UTC)

My guess would be that they perform binary search through the "dictionary" until the word is found or not found. As for finding the suggested correct spellings, I don't know, but whatever it is, it isn't very good. --YixilTesiphon Say hello Consider my Wikiproject idea 05:49, 7 December 2005 (UTC)
A Levenshtein distance is commonly used. The lower the distance, the better match. --Kainaw (talk) 14:47, 7 December 2005 (UTC)
For aspell, you could try reading the source. Dysprosia 00:38, 8 December 2005 (UTC)

Phalaenopsis orchid self-germination[edit]

Reader Andy has sent the following e-mail to the Wikipedia help e-mail desk.

"My phalaenopsis orchid is doing quite well and I was wondering how to go about growing new plants by either forcing a keiki or by self germination and growth on a nutrient gel."

I was able to help with information about the keiki but would be grateful if you could help out with information on self-germination. Capitalistroadster 06:24, 7 December 2005 (UTC)

niagara falls vs other falls[edit]

There are three really really spectacular waterfalls in the world, Niagara Falls, Iguacu Falls and Victoria Falls. My favourite are Iguacu, but I haven't seen Victoria yet. Angel Falls in Venezuala are the highest, and again, I fail it.-gadfium 08:27, 7 December 2005 (UTC)

backups[edit]

hey could anyone help me by explaining the importance of computer system backups! asap thannx so much!Charné--168.209.97.34 08:56, 7 December 2005 (UTC)

I had a really great essay about this exact same topic, but then my system crashed and I lost it ;) Gandalf61 09:53, 7 December 2005 (UTC)
  • grin*, Gandalf. Computers are fickle things, and it happens (with surprising regularity) that data on them gets lost. Your computer might crash, you could drop a brick on it, spill coffee on your laptop, or accidentally hit the delete key. If you have backups, you can get the data back. Just imagine what would happen if, tomorrow, your entire hard drive was emptied. What would you no longer have? Your documents? Your music? Your photos? Your programs? So that's why you make backups, so that when (yes, when not if) your computer crashes or dies on you, you will still have your documents stored somewhere safe. — QuantumEleven | (talk) 10:07, 7 December 2005 (UTC)
That reminds me... I once heard this little gem: "Real men don't make backups - but they often cry." --Pidgeot (t) (c) (e) 17:03, 7 December 2005 (UTC)
In the same direction, but with a different emphasis. In business, people put a lot of things on computers. Lists of customers, for example, or phone numbers of all the important suppliers. Banks put the details of your account. These days, many businesses, large or small, will simply be unable to work, and go bust, if they lose the information on their computers. So a backup doesn't just spare them from inconvenience: it keeps them in business. I read a news story about a medical researcher who had years of vital research on a laptop that was stolen, and it was all lost. I think the news story was supposed to make us sympathetic, but I think: what an idiot: I hope he has to pay back his research grants. Notinasnaid 19:05, 7 December 2005 (UTC)

Thanx guys the info was of some use and it even put a 'smile' on my face. Charné168.209.97.34

Digital camera and infrared photography[edit]

I have an HP R707 digicam. I want to know if it can capture the infrared and ultraviolet spectrum parts. If yes, would I need to use an image editing software to modify the levels etc to view the images? Thanks, =Nichalp «Talk»= 10:02, 7 December 2005 (UTC)

I don't know if your specific camera is sensitive to the Infra Red or Ultra Violet, though many digital cameras are so there is a good chance it has some response at at least on end of the spectrum. The way that this is normally achieved is through the use of a filter that will block all visible light from entering the lens. A peice of totally exposed developed black and white film actually works as a pretty acceptable filter for IR photography. Surprisingly it is hard to predict what colour CCD elements will respond most strongly to these wavelengths that depends on the composition of the CCD filters used in the particular model camera. Some cameras (for example many nikons) can be disassembled and the IR filter removed from in front of the CCD. This greatly increases their Infra Red sensitivity and means normal shutter times can be used, otherwise you can expect shutter times signifacntly longer than for visable photography. --Martyman-(talk) 10:27, 7 December 2005 (UTC)
  • Don't forget to use IR sensitive film. - 131.211.210.10 13:37, 7 December 2005 (UTC)

The CCD is sensitive to IR. A typical digicam has an optical filter to restrict IR exposure. You need to remove the IR filter and Bayer mask (for the absolute majority single CCD color models) and then install a filter that blocks visible light. This is surely not an easy job to most models. You could damage your digicam if you don't have the required resources (manuals, tools, cleanroom, skill ...). Anyway, you will lose you warranty. And if you want to do serious IR photography, you need cooling. However, withour proper tools, your digicam can be spoiled by condensation. Some videocams have a low light mode. I think that's IR photography at work. Maybe you can find yourself a cheap or used grayscale surveillance camera and modify it. -- Toytoy 14:47, 7 December 2005 (UTC)

OK, you obviously know a lot more about that than our Digital photography article does. Could you improve that article or write a suitable one? - Taxman Talk 15:35, 7 December 2005 (UTC)
  • Note that with a typical CCD camera, even in the best conditions you'll only get sensitivity in the near-IR up to about 1.1 μm. You won't be able to see anything in the dark unless you illuminate the scene with something like an IR LED (camcorders that have "nightshot" capabilities do this sort of thing.) For real "thermal vision", you need a cooled camera sensitive to mid-IR, which is an order of magnitude more complex and expensive. --Bob Mellish 17:04, 7 December 2005 (UTC)
Then how do we get a filter that only has one window at near-IR so it blocks visible light and mid-IR as well? I also don't know if a peice of totally exposed developed black and white film can be used as the filter because I am not sure if the silver particles would block all the light. Anyway, the wavelength of near-IR is longer so it can be less of a problem. You may want to attach the filter on the surface of the CCD to prevent loss of optical resolution. -- Toytoy 00:27, 8 December 2005 (UTC)

Electronic devices and circuits[edit]

What article titles would you say that is an interesting, important one for electronic devices and circuits, especially talking about analogue devices and circuits?

Try Electrical network? -- Daverocks 04:13, 8 December 2005 (UTC)

genetics[edit]

what is the gene product of tpmt and what is its primary function? 130.209.6.40 12:11, 7 December 2005 (UTC)

S. sanguinis[edit]

What is the average diameter of an S. sanguinis cell?

Organic chemistry[edit]

Although Acetyl Chloide has keto-methyl goup, it does not give haloform reaction. Why?

Are you sure it doesn't? I can't see any reason why it wouldn't.Keenan Pepper 02:12, 8 December 2005 (UTC)
Oh, I know why. The chloride is a better leaving group than the trihalomethyl group, so it leaves giving you trihaloacetic acid and chloride, instead of haloform. —Keenan Pepper 02:23, 8 December 2005 (UTC)
In any case, the haloform reaction is caried out in basic solution, so the acyl chloride functionality would immediately hydrolyse. Acetate ions do not give the haloform reaction. Physchim62 (talk) 15:47, 9 December 2005 (UTC)
Right, that too. =) I haven't actually taken organic yet; I was just making a guess because no one else answered the question. —Keenan Pepper 02:08, 10 December 2005 (UTC)

Lava Lamps and temperature differentials?[edit]

(since this might be an interesting addition to Lava lamp)

I purchased a desktop USB lava lamp during the summer, and was disappointed that the "lava" (in this case little reflective dots that are convected around in the denser fluid) would settle out of suspension after a few days. However, with the onset of winter and a colder office on average...the lava stays suspended and all is well.

I'm wondering why that is. Nothing else has changed in the setup. The lavalamp stays on all the time because my computer stays up all the time, so its not a case of thermal interia. The temperature drop in my office is at maximum perhaps 4 degrees (77F to 73F).

My guess is: unlike a normal lavalamp, the USB lamp is much smaller. The temperature difference between the area heated by the bulb and the outside surface of the lamp isn't that great, so larger convective patterns cannot develop in a warm office and the dots settle out.

Any thoughts? --Syrthiss 15:51, 7 December 2005 (UTC)

The problem is that lava lamps are highly dependent on specific gravity. The density of the lava must be carefully balanced with that of the remaining fluid; otherwise the lava will have the wrong buoyancy and either float or settle. Changes in temperature will change the density ratio between the lava and fluid. ᓛᖁ♀ 16:42, 7 December 2005 (UTC)
  • The particles are in a colloid, which are broken down by heat. --YixilTesiphon Say hello Consider my Wikiproject idea 20:24, 7 December 2005 (UTC)
    ...but if the colloid is broken down by heat it seems like a poor design for the lavalamp. There probably isn't much of a delta in the overall temperature of the resevoir when the lamp is placed in an environment that is 4 degrees colder, in comparison to the heat generated by the bulb itself? ie would the put a colloid in there that breaks down at say 79 degF but is stable at 76 degF? --Syrthiss 21:40, 7 December 2005 (UTC)
hehe fair enough. *shakes fist at manufacturer* --Syrthiss 04:02, 8 December 2005 (UTC)

CuO[edit]

What are the properties of CuO regarding photoelectrons?

Try [18]. --BluePlatypus 17:50, 7 December 2005 (UTC)

Carbon monoxide and multiple sclerosis[edit]

I was curious as to what year this information came to light?

"With chronic low-level exposure, similar neurologic injury may occur. Carbon monoxide acts as a potent neurotoxin, creating irreversible lesions in the brain's white matter (i.e., the myelin sheath). Such lesions, which are similar to those found in multiple sclerosis, can result in severe cognitive impairment."

I copied this off the webiste.

    • I wouldn't believe it without sources. The article is pretty awful in many other parts and gives no impression of being well researched. Some information can be gained at Carbon monoxide and the pages it links but I have never seen any claim that carbon monoxide is neurotoxic in the true sense of the term. Physchim62 (talk) 15:55, 9 December 2005 (UTC)

Sewage Treatment[edit]

Where do people find the Bacteria that are used for cleaning the sewge.I can not fully understand the biological stage in sewage treatment.Could someone explain it to me? Thank you

  • I'd imagine they come with the sewage, much like the yeast used to make wine come on the grapes. See sewage treatment and bioremediation. --YixilTesiphon Say hello Consider my Wikiproject idea 20:21, 7 December 2005 (UTC)
  • I suspect they are just there, in the environment. I did hear an interesting tale about cheese: apparently the hygiene requirements on cheese makers are tending to eliminate the bacteria which are otherwise just everywhere; this can stop the cheese from making correctly. Don't know it's accurate. Notinasnaid 21:01, 7 December 2005 (UTC)

Magnet[edit]

Is there any thin material that a magnet will not go through?

  • Mu-metal is efficient at screening magnetic fields, though I don't know how thin a piece you'd need to screen a typical magnet. --Bob Mellish 20:36, 7 December 2005 (UTC)

What would this be called?[edit]

The term cyborg, a portmanteau of cybernetic organism, is used to designate an organism which is a mixture of organic and mechanical (synthetic) parts. Generally, the aim is to add to or enhance the abilities of an organism by using technology. - From the cyborg article.

But what about the other way around? What would you call a computer that uses biology to enhance its function? For example, look at this news story of a group of 25,000 rat neurons hooked up to a flight simulator program. Imagine that a robotic drone or missile would use such a biological part (or even regular computers in addition to a synthetic CPU). Would you call these cyborgs or something else? Biocomputers maybe?

205.188.117.71 23:30, 7 December 2005 (UTC)

If I remember correctly biocomputing may be the right term. Dysprosia 00:36, 8 December 2005 (UTC)

Firefox tab extensions[edit]

I recently installed an update of tabbrowser extensions which broke my version of firefox. I'd love to keep using this extension but it's just too unstable. Does anyone know of other extensions that have a similar range of features? The ones I'm most interested in are Duplicate tab (opens new tab with an identical history) and being able to reorder tabs in the tab bar (via drag 'n drop). I've checked the mozilla site but nothing seems to offer the reorder tabs feature... -User:Lommer | talk 23:30, 7 December 2005 (UTC)

The current official version of firefox (1.5) lets you drag and drop tabs around, without the need for an extension. -- Finlay McWalter | Talk 23:33, 7 December 2005 (UTC)
sweet. -User:Lommer | talk 23:38, 7 December 2005 (UTC)
Ok, grabbed the newest version and all is good. Still missing that duplicate tab function though. I'll see if I can find an extension that fits the bill. -User:Lommer | talk 23:45, 7 December 2005 (UTC)
I went through the same process with Tabbrowser Extensions; it was great for a while, then kept getting more complex and less stable. Check out Duplicate Tab and Tab Clicking Options from Twanno's Mozdev page. HorsePunchKid 2005-12-07 23:54:08Z
Hmm, that looks interesting. Incidentally, I use tabpreview, which gives you a nifty pop-down thumbnail of each tab when you mouseover it, making it easier to find the tab you want, particularly when you have dozens of tabs with the same title open at once. -- Finlay McWalter | Talk 00:03, 8 December 2005 (UTC)
I find Tab Mix Plus to be quite stable, and a worthy successor to the ill-maintained but powerful Tabbrowser Extensions. Tzarius 08:48, 10 December 2005 (UTC)

Help on the element "Phosphorus"[edit]

Ok. A little question. What are the 3 most abundant of "Phosphorus's" isotopes? And at www.webelements.com, it said Phosphorus's crystal form is triclinic. So what could I rely more on, this site or webelements? I guess the majority who say a certain thing wins. Please help. (71.253.225.174)

I think he/she was referring to our page on Phosphorus, which says it's monoclinic, in contradiction to www.webelements.com. Both are misleading because the crystal structure of phosphorus is so complex — it has at least three allotropes (different crystal structures of the same element) and probably more weird hybrid forms and stuff. So, it can be either monoclinic or triclinic. —Keenan Pepper 02:00, 8 December 2005 (UTC)

It tells right there at isotopes of phosphorus that 31P is the only naturally occurring isotope, for all practical purposes. (The articles themselves aren't the proper place to leave comments, by the way, use the talk pages.) 32P and 33P are also created in trace amounts as decay products by cosmic radiation. Femto 12:53, 8 December 2005 (UTC)

December 8[edit]

what is the weight of air[edit]

The density of air, which determines the weight, depends on several factors, including the relative humidity, barometric pressure and altitude. The average value for dry air at standard temperature and pressure is ρSTP = 1.293 kg/m3. Titoxd(?!? - did you read this?) 01:44, 8 December 2005 (UTC)

Then multiply that number by the volume of air (in m^3) that you are talking about to find the mass (in kg). - Akamad 07:39, 8 December 2005 (UTC)
And the weight, in Newtons, is easily calculated by multiplying that by the local gravitational field strength. (About 9.81 N/Kg) --Fangz 08:15, 8 December 2005 (UTC)

Hepatitis B Virus[edit]

How long can the hepatitis B virus live in a droplet of blood?

I'm having difficulty verifying the information cited on the Ohio State University site, but according to this source, "...The hepatitis B virus (HBV), on the other hand, can remain infective for days in dried blood, months in serum stored at room temperature, and even decades when frozen."--
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 04:50, 8 December 2005 (UTC)

science - volcanoes[edit]

hy i am in grade seven and my text book doesint say why so if you could help me out than ...yah :-p why are some volcanoes more explosive than others?--24.64.223.203 03:59, 8 December 2005 (UTC)

if this could be answered by ...tomorow that would be wonderful thankyou


by the way GREAT website its helped me with sooooo much stuff :-)

oh and how do i find the answer to this LOL ha well anyways thxs

Glad you've found the site helpful. My minimal knowledge on the subject indicates that the explosivity of a volcano depends on the parent rock of the magma (thicker magma means more violent) and how much solid rock is on top of the magma plug which erupts. --YixilTesiphon Say hello Consider my Wikiproject idea 04:06, 8 December 2005 (UTC)

The explosiveness of the volcano tends to be due to the amount of gas that is dissolved in the magma, or how easily the magma plugs up causing pressure build up, and this is directly influenced by how viscous the magma itself is, which itself is strongly influenced by the mineral content of the magma at the particular location. Volcano is a good article to be reading, as well as the links at the end of it.--Fangz 06:18, 8 December 2005 (UTC)

The composition of the lava also plays a role. Volcanoes with acid lava tend to erupt much more violently (eg Mount Etna, Mount St. Helens...) than volcanoes with basic lava, where a gentle eruption lasting months at a time (eg Kilauea on Hawai'i, the Icelandic volcanoes...) are not uncommon. Whether the lava is acid or basic depends on where the volcano is situated — acid volcanoes are generally found on plate boundaries, while basic volcanoes form over mid-plate hot spots. — QuantumEleven | (talk) 08:51, 8 December 2005 (UTC)

pains[edit]

i ahve a pain in my lower left side.. i was just wondering waht was there that could possibly be giving me these pains?

External sources[edit]

  1. Sharp objects
  2. Blunt objects
  3. Tight clothing

Internal sources[edit]

  1. Dislodged bone fragments
  2. Neurological disorder
  3. Spleen
  4. One of those shrimp things from the Matrix

--YixilTesiphon Say hello Consider my Wikiproject idea 06:16, 8 December 2005 (UTC)

There is a great variety of possible causes for your pain. Wikipedia does not give medical advice, nor can conditions be easily diagnosed over the Internet. Please speak with your physician. — Knowledge Seeker 06:19, 8 December 2005 (UTC)
Most abdominal pains (including chest pains) are digestive (stomach/intestines). That creates a problem - when do you have a heart attack and when do you just have bad gas? --Kainaw (talk) 21:02, 8 December 2005 (UTC)

V/f curve[edit]

What is a "V/f curve" or "V/f characteristic curve? Is there a WP article where I could read more about it? --Angr (t·c) 09:19, 8 December 2005 (UTC)

  • Is it possible that your V stands for molar volume, and your f stands for fugacity? I can't tell off hand if that's what you mean by V and f, just happen to be the first things that popped into my head--Aolanonawanabe 05:14, 9 December 2005 (UTC)
  • Could this be an odd notation for conveying the critical parameters of an ideal solution? Or did I read into this too much?--Aolanonawanabe 03:54, 11 December 2005 (UTC)
  • On second third thought, my answer is making less and less sense the more I think about it, since molar volume over fugacity, wouldn't actually have any significance that would make such a notation useful--Aolanonawanabe 02:04, 13 December 2005 (UTC)
  • I suck at science. And I really have no idea what your talking about, however. Maybe this Link may have some relavancy? :D --Yardan \ Talk
It seems to be a property of AC electric motors and inverters—the relationship between frequency (= motor speed) and voltage. This page by Mitshubishi Automation tells more. Scroll down to the "Voltage to order" paragraph. –Mysid 10:12, 8 December 2005 (UTC)
  • More details about context would of course be helpful but let me point out a commonly known application where the V/f curve (voltage to frequency curve) is important: FM radio. The WP article doesn't mention the V/f curve but in short the relevancy is the following: FM is frequency modulation, which means that the signal (music e.g.) is broadcast by varying the frequency of a carrier wave. The receiver must than take this variaton in frequency and change it into variation in voltage. The loudspeakers will then take the variation in voltage and produce sound. If there is to be no distortion the receiver should have a linear V/f curve, i.e. if a change in frequency by one unit causes a change in voltage by one unit then a change in frequency by two units should cause a change in voltage by two units. The link [19] seems good, take especially a look at the section Receiving FM. Stefán Ingi 14:55, 8 December 2005 (UTC)
The context is inverters, which Mysid mentioned above. --Angr (t·c) 15:42, 8 December 2005 (UTC)

To make it clearer: The V/f curve is used in frequency inverters to control the relation of the frequency and the voltage of the electrical energy pushed to the motor. A three-phase asynchrone induction motor generally can't be fed with nominal voltage when running in subnominal speed. That would mean the current through the motor would be higher (there is a classical curve on the connection between rotation speed of an induction motor and the motor current available, unfortunately it's not depicted in the induction motor article). Basically, if you wouldn't use a lower voltage at speeds below nominal, the motor current would grow much larger, resulting in some black smoke and a broken motor. Because of that, you use a V/f pattern (in simple frequency inverters) to make sure the motor isn't treated badly. Sometimes it could be preset, sometimes you have to make one for yourself (specifically tuned etc). More advanced frequency inverters implementing motor current supervision aswell, not always need this setting to be made (they use other control types than a simple V/f pattern - like open loop / flux vector / pulse generator feedback etc). TERdON 23:41, 8 December 2005 (UTC) PS: Regular inverter (the digital, negating kind) as far as I know, aren't related in any way), they only deal with digital logic. TERdON 23:44, 8 December 2005 (UTC)

MS-DOS Prompt[edit]

For example, I am now in the C drive, I want to go to the folder "WINDOWS" in the c drive, so I type "cd Windows", and the command line intepreter turned into "C:\>WINDOWS>. I then do the stuff I need to do, and want to leave this directory to go back to C:\, how do you leave a directory and go back to the original directory? i tried "cd C:", and "C:" but it didn't turn out to be working... How does one return to the previous directory?

cd.. -- Ec5618 09:43, 8 December 2005 (UTC)
Or cd \ Notinasnaid 09:48, 8 December 2005 (UTC)
To clarify,
cd ..
takes you back to the directory above where you currently are (e.g: C:\Windows to c:\ or c:\Windows\system to c:\windows).
cd \
takes you to the root directory of the drive you are on, regardless of where you are. Thryduulf 09:54, 8 December 2005 (UTC)

Electromagnetism and Gravity[edit]

please correct me if i am wrong, but i came across the fact that electromagnetism is a stronger force, compared to gravity.

for instance, i have a negatively charged piece of material, and throw a positively charged material into the negatively charged piece (both have same size, mass). The negatively charged material is placed on the floor, and one drop the positively charged materil above the negatively charged material, will it repel? by repel i mean the positively charged would be "bounce" off from the negatively charged.

if this is true, we human, when falling off a cliff, should be able to survive. because we are composed by atoms, and at the exterior of the atoms there are electrons. the floor is bonded so that the electrons are circuling the floor. in theory, when i fall, the electrons in my body should repel the floor's electrons as both is at the exterior, am i right?

In response to your first question, "electromagnetism is stronger than gravity" is not exactly true. More correctly, you would say that "electromagnetism prevails at small distances, gravity at large distances". It's true that, for two object close to each other, the electromagnetic forces between them will be stronger than the gravitational forces between them ("electromagnetism prevails"). However, for the same two objects at very large distances from each other, the electromagnetic forces are much smaller than the gravitational forces between them ("gravity prevails").
In response to the second half of your question, you are correct: the repulsive forces between the electron shells in the atoms of the ground and the electron shells in the atoms of your body repel each other. But all this means is that the two will not pass through each other - you stop when you hit the ground, instead of passing through it. All the atoms composing your body will come to rest at ground level (your body will still be there!). What kills you when falling off a cliff are the forces acting on your body to cause you to stop so suddenly - your body will be crushed and deformed, and this kills you.
(aside: what happens when two atoms are mashed together strongly enough to overcome the repulsive forces between their electron clouds is called nuclear fusion, and it's the process which powers the sun. But the energy needed is much, much greater than someone falling off a cliff!) — QuantumEleven | (talk) 10:33, 8 December 2005 (UTC)
Sorry, I screwed up on my first explanation (and I didn't read your question properly :( ). Whether or not the object will "bounce" depends on how much charge it has - the repulsive force between it and the object on the ground must be stronger than gravity. However, in most everyday situations, you should be able to give an object enough charge so that it will be repelled by an identical object lying on the floor. It won't 'bounce' straight back up - that kind of repulsion is not stable - it will most likely be deflected and land to the side of the object on the floor.
Concerning whether the electromagnetic force is 'stronger' than the gravitational force, yes it is (see Fundamental interaction) - by about a factor of 1036. So for objects which have about the same amount of mass as they have charge (so on the order of 1 Coulomb per kg), the electrostatic forces between them will greatly outweigh the gravitational forces between them. For many everyday objects, this is the case, so the electrostatic force between them will dominate the gravitational force (why, for instance, your hair will stick to a balloon which you've rubbed on your sweater). However, when you start talking about very large objects (planets, stars, solar systems, galaxies...) they have much, much more mass than they have charge, so despite the fact that electromagnetism is stronger than gravity, the gravitational forces between them dominate, and the large-scale structures of the universe are almost entirely determined by gravity alone. — QuantumEleven | (talk) 11:00, 8 December 2005 (UTC)
I don't know much about these forces, but I thik there is another problem here (we know there is a problem, since we don't survive falls from high cliffs in general). This is assuming that if you bounce you aren't hurt. It's easy to assume that the bouncing is what matters (e.g. jumping from a cliff onto a trampoline.) But you could also jump into soft materials and not bounce and perhaps survive. What injures and kills on a fall is the sudden stop. The edge of your body stops, and your bones and organs keep going, smashing into the bit between themselves and the ground. They damage other parts of your body, and themselves. By making a stop less sudden, we reduce this injury. In some cases, the thing we land on takes up our energy and we bounce, but that's just a side effect. Subatomic forces might stop you (well, I guess they do: it's really hard to make the atoms from two solids mix; but I don't know if they are the same forces as mentioned). But they will probably not take effect until you are a fraction of a millimetre from impact, and so the stop will still be sudden and uncomfortable or fatal. Notinasnaid 11:17, 8 December 2005 (UTC)
I personally believe that the whole "gravitational force" theory is bunk. You can produce the same effect and keep all the same gravitational formulas using kinetic force of atomic and subatomic particles without gravity. But, until Einstein is reincarnated and says so, nobody will consider it. --Kainaw (talk) 15:48, 8 December 2005 (UTC)

From strongest to weakest, the fundemental forces of nature are the strong nuclear force, teh weak nuclear force, EM, and gravity. Their strength is also inversly proportional to the distance they act over -- the strong nuclear force acts across distances proportional the size of a proton; on the other end of the scale, graivtyu acts across billions of kilometers. Raul654 16:18, 8 December 2005 (UTC)

what is SPAM?[edit]

'Sup,what is spam and how do you delete it? Can you also tell me how messages in the email system managed?what's the difference between spam and junk mail? could you possibly list the default settings on a computer and kinda explain them to me? thanks a million...i will appreciate any feedback and assistance a.s.a.p Charné168.209.97.34

  • What is spam? Mail you don't want.
  • How can you delete spam? In your e-mail program there will be a delete button or similar.
  • What you didn't ask: how can you prevent spam? You can't completely, but there are many programs and services which screen your mail and try to recognise spam, then delete it. These will unfortunately sometimes delete real mail (e.g. a joke from a friend that mentioned viagra). You can also prevent or reduce spam by keeping your e-mail address a secret and making sure it can't be guessed.
  • Spam and junk mail are probably the same thing for your purposes.
  • No, I don't think we could list the default settings on your computer. Firstly, you don't tell us what kind of computer you have, and what software you have on it. Second, modern computers have thousands, or tens of thousands of settings. This is a major series of books, not a reply! If you have more specific questions, please ask.

Notinasnaid 11:09, 8 December 2005 (UTC)

(after edit conflict)
Spam is electronic junk mail — a bit more precisely, spam is e-mail you don't want and didn't ask for. It can be any number of things - advertisements, invitations to fraudulent schemes... (we have very good articles on Spam and E-mail spam). To delete spam, (assuming you're using an e-mail client, such as Outlook Express or Mozilla Thunderbird), just click on the offending message and press the delete key on your keyboard. :)
As to the rest of your question, I'm not entirely sure what you mean. Which "e-mail system" are you referring to? Which e-mail program do you use? I am going to go out on a limb and guess that you are getting lots of Spam mail and want it to stop. Welcome to the wonderful world of the internet...
Dark humour aside, spam is a real nuisance to many e-mail users. The spammers (people who send you the trash now cluttering your inbox) probably got your address by 'harvesting' (reading) it off a messageboard or something, so, first rule for avoiding spam: never post your e-mail address on the internet if you can (in chat rooms, messageboards, on wikipedia...). Perhaps get a second e-mail address for "internet stuff", you know, to sign onto websites and such, and keep your main e-mail address for e-mailing your friends - that way, your main e-mail address stays clean of spam. Free e-mail services like Hotmail are great for getting a second (or third, or fourth) e-mail address.
Spammers use other evil tricks to get your address. They will send out messages to millions of e-mail addresses, most of which will be wrong or nonexistant. The messages they send often include a link to "unsubscribe" - but what often happens is that, by clicking the link, all you do is tell the spammer that your e-mail address is 'real', so encouraging more spam. Therefore: never click on any link in a spam e-mail (and, for heaven's sake, never buy anything advertised in spam!)
Check with your ISP (the company you get your internet connection from) - many now offer spam filters for their e-mail addresses, see what they offer. Alternatively, you can try to do some e-mail filtering on your own computer. Filtering is a fancy name for an automated process whereby your computer tries to guess if an e-mail is Spam or not, and then does something to it if it thinks it is (deletes it, moves it to a different folder...). It's still not 100% accurate, but getting better. However, if you want to set up filtering yourself (as opposed to just using your ISP's filter) it up can be a bit tricky, and it's hard to recommend a specific program without knowing more about what kind of computer you have, what kind of e-mail you use (from your ISP, web-based...). Maybe some of the more informed people on here can give you a few tips.
One last word of advice: be wary of anti-spam solutions that look too good (yes, I know, that's a very vague criterion) - scammers are now trying to bait you with phony "anti-spam" programs which, at best, do nothing (but sometimes costing you money!), and, at worst, install all sorts of nasties on your computer. Check with any computer-savvy friends (or ask here!) before installing any anti-spam program you're not sure about. Good luck! — QuantumEleven | (talk) 11:27, 8 December 2005 (UTC)
I have actually received spam advertising anti-spam software. Aside from their mere nerve to do it annoying the hell out of me, I am sure that if I were to buy and install their software, all it would do would be to purposefully attract more spam. — JIP | Talk 11:51, 8 December 2005 (UTC)
  • Lots of good advice up there. There's several approaches you can do.
    • Help put a SPAMMER in the SLAMMER ... visit www.ftc.gov to see how you can help your government apprehend criminals ... there's various things you can do when you get spam that is obviously criminal, to help see to it that the criminals get reported to agencies interested in apprehending those criminals ... be prepared to be frustrated, the e-police are often like keystone cops.
    • Learn how to communicate on the Internet without publicizing your e-mail address to lots of strangers, which is a huge topic by itself. Then after having done so, go thru the process of changing your e-mail address to one in which you will practice what you learned. Notify legitimate contacts of your new e-mail address, and discontinue using the one that is now glutted with spam. Expect to have to change e-mail addresses every few years just because of this problem.
  • It may be of interest to you how I protect myself. Incidentally I have been using the Internet since the 1970's and have been using computers since the 1960's. I have a multi-leveled defense against viruses, hackers, spam, and other variations of malware.
    • I use an ISP which intercepts a lot of this garbage before it even gets to my home.
    • I have a hardware firewall that intercepts a lot of this garbage before it even gets to my PC.
    • I use a lot of tools connecting to the Internet which involved encrypted communications so that anyone listening in on my Internet communications is going to have a hard time, and be tempted to move along and attack some easier target.
    • I have a suite of Internet security tools running in the background on my PC all the time to try to intercept this garbage before it can do any damage.
    • I have more than one anti-spyware product on my PC which I run periodically.
    • I keep my anti-virus definitions up to date and run a total scan periodically.
    • I stay informed on the inadequacies of these tools so that false positives are less likely to bite me.

AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 02:32, 9 December 2005 (UTC)

still need some help![edit]

Ouch!i'm new at this computer geek thing so don't bite my head off plz?Could you at least list 5 common default settings.Could you also help with the procedure on what to do if your computer is infected with a virus(and what not to do)? what precautions should you take when opening an email message? my research report has to be in by 15h00!THANX Charné168.209.97.34 11:36, 8 December 2005 (UTC)

I'm not going to bite off your head, but I will ask you to DYOH (Do Your Own Homework) - see the instructions at the top of this page. To get you started on your second question, you can try reading our article on computer viruses, or this. A Google search can probably help you with your third question. Good luck! — QuantumEleven | (talk) 12:52, 8 December 2005 (UTC)
15h00 in what time zone? Contrary to what you might think, your homeland is not the whole world. — JIP | Talk 12:55, 8 December 2005 (UTC)
  • If your computer is infected, run a virus scan with a anti virus software (ie norton, kaspersky.) What not to do? Well, it greatly depends on what kind of virus your infected with. Don't send emails (cuz' virus may auto attach to them and infect the receiver.) To be on the safe side, don't do anything at all.. run teh virus check! precautions before opening a email, well.. check the subject line, if the subject looks doubtful, don't open it? I'm far from any security expert myself, and I doubt the 'random' pc user is. But these tips just seem logical. --Yardan \ Talk
For the question on defaults, you might start at Default (computer science). Chuck 16:35, 8 December 2005 (UTC)
  • Since you said your report has to be in by 15:00, I'm assuming you're writing this on the same day it has to be finished. Usually, it's a good idea to start these kind of things earlier. It makes finding the required information a lot easier. - 131.211.210.16 08:45, 9 December 2005 (UTC)
    • There is something to be said for learning how to do things at the last minute. In the real world when someone asks us for something in business, they usually expect it done IMMEDIATELY and they REALLY need it YESTERDAY. So people, who can learn to do assignments exceptionally well in next to no time, will have a great competitive advantage in the modern business world. AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 20:37, 14 December 2005 (UTC)

Eyes and shifting perspective in photographs[edit]

Caldera or Hills? (on Olympus Mons)

This has been bugging me for a while. As a space enthusiast, I love looking at pictures of features on other planets and moons. However, often I find that when I look at pictures of three-dimensional objects (such as the caldera of Olympus Mons, on the right), about half the time my eyes seem to suddenly 'shift', and I'm seeing things 'inside out' (in this case, it seems as if the caldera depressions are suddenly hills!). I know that they're supposed to be depressions, and sometimes I can force my eyes to 'shift' back to seeing them as depressions, but not always. Is there something wrong with my vision? Or is it a peculiar features of pictures taken from high altitude? — QuantumEleven | (talk) 13:21, 8 December 2005 (UTC)

This is a pretty common bit of visual trickery - I've a map-reading manual from the twenties which discusses it in some depth, suggesting it's common, but never thought to look for it elsewhere. Try finding a topgraphical map and looking at it, not paying attention to anything but the contours, and you'll find that the valleys suddenly become ridges, the hills bowls... It's normally not a problem in the "real world", as we have things like rivers and streams and puddles - glancing at the watercourses always makes it obvious which way is down. It is pretty neat, though. Shimgray | talk | 13:57, 8 December 2005 (UTC)
I can't remember the name of it but it is a noted thing in psychology. There is a way of using this to test how introvert/extrover you are. Basically you get a drawing of a wire frame cube and put x marks in the top corners of one of the squares, over the course of a minute you then note how many times the crosses switched from being on the front square to the back square and vice versa (its easiest if you signal to someone else when it changes and get them to count and time). I don't know how reliable it is, but it seemed to work for our class of ~25. IIRC the range was from about 30 to about 115 flips per minute, with introverts at the low end and the extroverts at the high end. I'll look this up when I get home this evening, unless someone has beaten me to it. Thryduulf 14:16, 8 December 2005 (UTC)
By the way, if anyone cares at this point, this is called a Necker Cube. See also the head of Crow T. Robot during a movie segment.
  • I also have this problem. I find it helps to think about where the lgiht would be coming from. --YixilTesiphon Say hello Consider my Wikiproject idea 14:31, 8 December 2005 (UTC)
    • It doesn't just "help", it's the answer to the question. If you know the direction of the light you can easily distinguish between the two, because it tells you whether a lit surface is interior or exterior. --Fastfission 21:34, 8 December 2005 (UTC)
Normally when we look at geographic features, there are additional depth cues on which we can rely. The little bit of scattering provided by atmospheric dust and haze–even under very 'clear' conditions–is enough to let us know which parts of a scene are farther away. (Artists use this all the time in painting landscapes, see atmospheric perspective). If you're moving, parallax gives you an additional cue—relative to the surrounding terrain, a hill will 'move' differently from a crater.
When you look at an overhead photograph of Mars, the Moon, or some other astronomical object with little or not atmosphere, you don't get either clue. There's no way for your brain to decide which part of the image is nearer to the observer, so it pops back and forth.
As for the introvert/extrovert thing that Thryduulf mentions....I dunno.... TenOfAllTrades(talk) 15:07, 8 December 2005 (UTC)

See also Multistable perception. Femto 15:16, 8 December 2005 (UTC)

I notice that if I rotate the image to have the lighed parts facing up the features look like hills and just the opposite if rotated 180° (lighted parts facing down the fearures appear to be depressions). --hydnjo talk 15:34, 8 December 2005 (UTC)
  • That's probably just because it is less intuitive to assume light coming from the "bottom" of a picture (even though in reality, with 2D aerial maps there is no reason to assume one direction over any other). --Fastfission 21:34, 8 December 2005 (UTC)
I have tried and tried, but whenever I look at the image I just see hills, I can't get it to flip to craters. I have looked at Image:Olympus Mons.jpeg, so I know they are really craters. I have also tried different rotaions. Is there something I can do? I know I have trouble seeing stereoscopic images, so can someone tell me if it still flips with one eye open.--Commander Keane 23:57, 8 December 2005 (UTC)
This is interesting. I see hills though, not craters. It probably has to do with the shading/lighting --HappyCamper 02:10, 9 December 2005 (UTC)
oh, I remember this picture... I see hills usually, but occasionally they become craters instead. It's an interesting phenomenon; if you're attentive enough, you may notice the flat surfaces seem to drift in a particular direction when the image flips, indicating there's some postprocessing going on in your visual system. If you have trouble seeing both orientations, try focusing on a small area until you can get that part to flip; the rest may follow. Defocusing your eyes briefly may help too. ᓛᖁ♀ 03:41, 9 December 2005 (UTC)
Here's another instance of this sort of reversal. Go to the Google Maps web site and choose a large city that you're familiar with, and a location in the city with tall buildings. Zoom in all the way, and go to the satellite image. (This won't work everywhere in the world, as their coverage is uneven. Note that in some places, like Paris the last time I looked, they have good satellite coverage but not good map coverage.) Anyway, if the location is in the northern hemisphere, when you look at the satellite image the buildings are likely to look weird. In some places where tall buildings are close together, you may see buildings in what are actually the spaces between them. This is because they show north at the top, but the sun, being over the tropics, is lighting the images from the south. If you have a program that can invert the image, putting south at the top, it will look more natural that way. --Anonymous, December 9, 2005, 07:15 UTC.

SATELITE DISHES[edit]

What material do they use for making satelite dishes

  • See our article on them. Also, please don't post in all capital letters. Bart133 [[User talk:Bart133|(t)]] 19:40, 8 December 2005 (UTC)

Saponification of Oil/Fat Stains[edit]

Are oil or fat stains converted to "soap" (saponification) when detergents or cleaners (such as sodium ccarbonates, percarbonates, etc.) are dissolved in water? Is this an ester and/or process of hydrolysis? Thank you.

--Curious

Check saponification, surfactant, and emulsion. When detergents disolve in water they typically involve the latter two. See saponification for how that goes down. - Taxman Talk 20:19, 8 December 2005 (UTC)
Most common fats are esters: saponification is the alkaline hydrolysis of esters. This is one of the processes at work in dishwashers and oven cleaners. Physchim62 (talk) 16:00, 9 December 2005 (UTC)

What are the 8 types of gluons?[edit]

I was reading about gluons on this site, and I found that there are 8 types. There are 3 "colours" in quarks and gluons: red, green, and blue. I already know 6 types of gluons: Red-Antigreen, Red-Antiblue, Green-Antired, Green-Antiblue, Blue-Antired, and Blue-Antigreen. What other types could there be? Can someone please help me? Thanks-Max P.S. Do photons have volume?

I think this is one of those things very few people in the world actually understand. This page attempts to explain it: http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/gluons.html
As to whether photons have volume, well, the question is pretty much meaningless. Photons aren't like little spheres; they don't have an inside and outside, so they can't really take up space. They are governed by a probability wave which says what location they would most likely be if you measured it, but you can't really call that a "volume"... —Keenan Pepper 23:57, 8 December 2005 (UTC)
  • And while you're at it. Most atoms aren't really spheres either even though they're often depicted as such for ease of use. The area in which the electrons can be found (around the nucleus) may differ depending on other atoms in the area. A lot of it is empty though, so it wouldn't really be fair to count that space as volume either. - 131.211.210.16 08:50, 9 December 2005 (UTC)
First, recognize that you don't know what a particle is. In quantum theory, a fundamental particle is something that might be either wavelike or a particle-like, but not both; or else it might be both wavelike and particle-like, or else it might not be either. Dig deeper, and realize that a fundamental particle is an irrep of a symmetry group (or rather, a quantum field valued in an irrep of a symmetry group). Then, follow electroweak theory and QCD to see why the symmetry group in question has to be SU(3). The gluons follow. It's a long path, so be patient. -lethe talk 14:47, 9 December 2005 (UTC)

December 9[edit]

Home made clean room[edit]

It has been suggested that running a hot shower will raise the humidity in your bathroom (assuming thats where your shower is) and in turn the humidity will drive dust out of the air, making it a semi-clean environment. Is that possible? Logic would suggest that more humidity would raise the Specific gravity of the air and in turn make it easier for dust to stay airborn. It would raise the temperature (and hence lower the sp.grav.), or possibly the humidity would condense on the dust particles and cause it to precipitate. Which one of these theories is correct? As a bonus, what are some low cost methods someone could use for running a clean room, aside from a hot shower? WP does have a moderately informative article on Clean Rooms. Thanks! --Jmeden2000 00:07, 9 December 2005 (UTC)

I'm pretty sure you'd just wind up with a moldy bathroom, remember, some things like warm, moist environments, and grow very well there--Aolanonawanabe 02:01, 13 December 2005 (UTC)
  • The trick isn't the elevated humidity precisely; what's useful are the very fine droplets of water created by the shower. The droplets are pretty big relatively to most of the other dust and crud in the air, and they fall fairly rapidly. So if you run the shower for a while and then turn it off, you get two handy effects. First, the dust in the air will tend to get stuck to the droplets and get pulled down with them; this gives you nice clean air, relatively speaking. Second, the droplets–as well as any water vapour that condenses–will form a temporary barrier that binds and settles dust on the room's surfaces. Hmmm...I'm not sure precisely how much benefit you get from dust particles acting as nucleation sites for new droplets; the importance of that process probably depends on how efficiently your shower generates its own aerosolized water droplets.... TenOfAllTrades(talk) 02:03, 9 December 2005 (UTC)
Interesting... So in essence you need to make it rain in your bathroom, by creating a warm humid air mass circulating into a colder region so that the vapor condenses into a mist and precipitates taking the dust with it, in much the same way that full scale rain pulls pollen out of the air. I wonder how effective this is compared to doing something like running a low-micron air filter taped to a box fan (a trick i used when painting cars in my garage). --Jmeden2000 14:39, 9 December 2005 (UTC)

palm pilot[edit]

I would appreciate a concise explanation of what a palm pilot is and can do. Thank you.

See our article on the Palm Pilot. TenOfAllTrades(talk) 02:04, 9 December 2005 (UTC)

Loading an excel database into ASP.NET[edit]

Is there any easy way to do this? Or do I need to use sql? I want to load a bunch of books to a website to let people purchase them.

You should be able to use an Excel database as a data source in ASP. You need to instantiate an ADO Connection object, and install the Microsoft Data Access Components on your Web server. You will need to use SQL as part of the ASP script to query the database. --Canley 06:02, 9 December 2005 (UTC)

Identification of planes[edit]

I took these photos at the War Memorial in Canberra, and I was wondering if anyone could identify the machines?

Last two aircraft, at a guess, may be a de Havilland Mosquito and (more confidently) a Messerschmitt Bf 109. Shimgray | talk | 12:30, 9 December 2005 (UTC)
Yes, it's a -109. [20]. Polly, in the second photo, is a P-40 Kittyhawk. [21], which also comments on the "Mosquito, with its formidable red and black propeller spinners", so that one's right. Shimgray | talk | 12:40, 9 December 2005 (UTC)
Our Australian War Memorial article notes that it contains a Mark IV tank from WWI, and the tank certainly looks like one, so count another in. Shimgray | talk | 14:57, 9 December 2005 (UTC)
The top right looks like an SE5, which the RAFC used in WWI. [22] gives a better picture about half way down. DJ Clayworth 03:13, 12 December 2005 (UTC)
The remaining plane looks shipboard and vaguely Japanese, and this page notes that the RAAF rebuilt a A6M Zero. It's hard to be sure, but it looks like it. Another picture here DJ Clayworth 03:25, 12 December 2005 (UTC)

Well thank you very much everyone for helping me out. I added the idents to the photos. --Fir0002 06:46, 12 December 2005 (UTC)

SATELITE DISHES[edit]

IS THERE ANY SPECIAL MATERIAL USED FOR MAKING A SATELITE DISH

After brief googling it seems that many satellite dishes are made of galvanized steel and are finished with polyester powder coating—like this one. –Mysid 07:47, 9 December 2005 (UTC)
  • Bart133 also gave a useful response to your earlier request here (a few posts above in this list). - 131.211.210.16 08:46, 9 December 2005 (UTC)

Homemade explosives[edit]

I'm searching for a category name for explosives that could be made at home. Best idea at the moment would be "Homemade explosives". Anyone has a better idea? --helohe 12:07, 9 December 2005 (UTC)

What about Category:Don't try at home? ᓛᖁ♀ 12:25, 9 December 2005 (UTC)
This is a nice name but does not exaclty tell whats meant. It could be a second category though. helohe 13:13, 9 December 2005 (UTC)
How encouraging... :) ☢ Ҡieff 15:13, 9 December 2005 (UTC)
Why not Category: Please try this at home. Make a REAL BIG one and kill yourself. One less person to deal with. --Kainaw (talk) 15:21, 9 December 2005 (UTC)
We done most of this dangerous stuff at school and therefore its quite legitime to have this as a category. Also its up to the one who creates this stuff if he wants or not. Also the articles are not step by step instructions so you need a chemical knowledge anyway. I think it is quite interessting what can be made at home with very simple things.
How about Category:Department of Homeland Security, that way they'll know which IPs to monitor. Physchim62 (talk) 16:04, 9 December 2005 (UTC)
I dont care as I dont live in the us. And I'm a active (pacifist) Anarchosyndicalist so they'r monitoring me anyway. helohe (talk) 16:20, 9 December 2005 (UTC)
  • Improvised explosives? --Fastfission 17:37, 9 December 2005 (UTC)
    • Thats good, I'm considering using that one. --helohe (talk) 21:40, 9 December 2005 (UTC)

Please assure us you are not planning to put bomb recipes here. alteripse 00:57, 10 December 2005 (UTC)

  • Start with Explosive material and then get back to us with any specific questions you may have. Please be sure to add your address to any future questions. We will see to it that you get help. --hydnjo talk 04:12, 10 December 2005 (UTC)
  • Not to worry. If the explosive articles are like the Siegenthaler one, we'll learn that ANFO is 40% amonium nitrate and 60% butterscotch. -- Finlay McWalter | Talk 04:16, 10 December 2005 (UTC)
  • Well then it wouldn't be ANFO would it. It would be more like ANBP.  ;-) --hydnjo talk 04:26, 10 December 2005 (UTC)
  • Wikipedia is a encyclopedia so no recipes. recipes go to wikibooks. helohe (talk) 16:14, 10 December 2005 (UTC)

99% of all explosives produced by mankind was made only for the killing of people. Why would you want to make explosives? --Eye 23:38, 10 December 2005 (UTC)

  • "Es gibt viele Arten zu töten. Man kann einem ein Messer in den Bauch stechen, einem das Brot entziehen, einen von einer Krankheit nicht heilen, einen in eine schlechte Wohnung stecken, einen durch Arbeit zu Tode schinden, einen zum Selbstmord treiben, einen in den Krieg führen usw. Nur weniges davon ist in unserem Staate verboten." - Bertolt Brecht. -- helohe (talk) 02:31, 11 December 2005 (UTC)

snakes[edit]

do snakes have ears?

  • You could ask them, but depending on the outcome, they might not be able to hear you (:, also try here Snakes#Perception--Aolanonawanabe 13:32, 9 December 2005 (UTC)
  • Snakes don't have external ears, but they can sense sound. I remember hearing (HA!) that they pick up vibrations through the ground with their bodies. TheSPY 18:05, 12 December 2005 (UTC)TheSPY

Particle Language[edit]

I humbly apologize for this intrusion into your life. I am in need of your assistance. I have tried to search the web and other material, in relation to an experiment or a paper. The nature of which: - a group of particals in one part of the world were interacted on to alter their spin. As a result a group of particals in an other part of the world were observed to change at similar instance. For visualization purpose of the article I seek : - That is to say that the particales at one end were red and blue at the other end. At the moment of change the red turned blue and the blue turned red.

Could you please send me a link to a page were I might find said such. I thank you for your time and patience. And shall at all times remain in your debt.

I am in desperate need of such information.

See EPR paradox. -lethe talk 14:36, 9 December 2005 (UTC)

Bows b4u i am humbled by you. I have been to look at your pro.......very nice indeed oh wise one. Smiles.....I have not forgoten this deed you have done... and shal get back to you. Yes this link has helped........I still search for this latest paper as describe...bows Bless'ns.

Are you for real?--Eye 23:42, 10 December 2005 (UTC)

Agent Orange[edit]

Can you tell me what possible birth defects could be involved if a father had extreme exposure to agent orange? Specifically lung envolvement in the son. My e-mail is (email removed). Anything would be helpfull. Thanks Kim

Our agent orange article says "The VA has listed prostate cancer, respiratory cancers, multiple myeloma, type II diabetes, Hodgkin’s disease, non-Hodgkin’s lymphoma, soft tissue sarcoma, chloracne, porphyria cutanea tarda, peripheral neuropathy, and spinal bifidia in children of veterans exposed to Agent Orange as side effects of the herbicide." -- Finlay McWalter | Talk 14:48, 9 December 2005 (UTC)
Wikipedia does not give authoritative medical advice. If you are personally worried about this, I recommend you consult a doctor. --Fangz 02:46, 10 December 2005 (UTC)

Highest resolution Digital Camera[edit]

What is the highest resolution digital camera available at the moment? helohe (talk) 15:44, 9 December 2005 (UTC)

  • Well, Hasselblad's H1D boasts 22 megapixels. --jpgordon∇∆∇∆ 19:49, 9 December 2005 (UTC)
    • Wow, thanks. Seems to be a great camera but its quite expensive ($ 26995.00). helohe (talk) 02:43, 11 December 2005 (UTC)
usually such extreme cases aren't that useful for normal use and as it's the best very expensive. also i believe there is more to a good digital camera then just a high resolution. Boneyard 13:37, 12 December 2005 (UTC)
Shure high resolution is not everything. But it is very useful if you want to create real big images of landscapes etc... . Btw. I just found that Phase One has a digital back (P 45) with 39 MP. helohe (talk) 14:24, 12 December 2005 (UTC)

organic chemistry[edit]

Although Acetyl Chloride has a keto-methyl group, it doesn't give haloform reaction-why?please give me the mechanism also.

  1. See the responses to your identical question above;
  2. Check our articles on haloform reaction and acetyl chloride, it's much quicker than asking here;
  3. If you're still stuck, check our article on ketone;
  4. Do your own homework, and be thankful you're not in my organic classes or you'd really find out what sarcasm means.
Physchim62 (talk) 16:09, 9 December 2005 (UTC)
This question is already answered above, from the first time you asked it. —Keenan Pepper 02:12, 10 December 2005 (UTC)

Television broadcasting sattelites[edit]

What protocol/encription is used in the communication with sattelites that are used by live tv broadcast teams (mostly mounted on tv-cars)? Is it possible to capture/'listen' to this signals with help of some computer equipment? Is it possible to transmit custom data to this sattelites? Are there differences by country? Where (coordinates) are this satellites located. And in general does there exist any software that can be used for data-capuring with as input a card for the pc with connection to a satellite dish so this data can be analysed? helohe (talk) 16:12, 9 December 2005 (UTC)

For many of your questions the answers are YES this is technically feasible AND to do so is illegal in most of the western world, unless you are a technician with the company providing the infrastructure services, or are armed with a warrant signed by a judge granting you permission to do this access. Now if I was to say HOW to do this stuff, I could be charged as an accessory to someone doing the crime. AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 20:43, 14 December 2005 (UTC)

Infrared and Ultraviolet[edit]

The limits to colour vision could not be the exact same for everyone. So there must be some wavelengths of UV and IR that only some people can see but would be invisible to others. Is there anything that effects one's limit? Would a baby exposed to wavelengths above red or below violet have more sensitivity? Wouldn't they make the ultimate spies? And is there somewhere (e.g. a website) where one could test their vision limit.
I'd like these questions answered about sound also. Thanks. EamonnPKeane 18:35, 9 December 2005 (UTC)

For vision I the range is limited by the absorbion spectra of rhodopsins, although I don't know if age-related changes in the availablility of the photoreceptor cell cause a preceptual change. As to sound, young humans can (theoretically) hear in the 20 Hz to 20KHz range, and that top value reduces as the child ages. I don't know why, but I'd guess it's due to the increasing size (and thus mass, and thus inertia) of the ossicles. There's a bit more at the hearing (sense) article. -- Finlay McWalter | Talk 18:45, 9 December 2005 (UTC)
(1) I've been told that newborn babies see in the ultraviolet range, but lose this ability within a few days. (2) The outer edges of human vision occur at/around 400 (very dark red) and 700 nanometers (violet). As far as people who can see this, I am not sure. (3) As far as sound, it has been claimed that certain children can hear up to 25 Khz, but those claims are debatable. Once sound gets to a certain very high frequency, it becomes less about "hearing it" than percieving it (I can say this first hand -- I had the precise range of my hearing tested a while back. I heard up to 16,750 hz, but above 15,000 it was virtually impossible to localize the noise) Raul654 18:50, 9 December 2005 (UTC)
  • The short-wavelength limit of vision is about 390 nm and is set by the UV-opacity of the cornea. (The S-cones are actually sensitive down below that, but no light can get to them). People who have corneas thinned due to disease or surgery can reportedly see some UV light down to about 300 nm. The long-wavelength limit is less sharp - about 780 nm is just visible, but sufficient intensities (e.g. lasers) up to about 800 nm can be seen (though this is very dangerous to your eyesight). --Bob Mellish 18:59, 9 December 2005 (UTC)
That said, there is one group of humans who have different colour perception than most. Although our color vision article doesn't mention it, there is a rare mutation which (only in women) causes the formation of a fourth cone cell type. This cell's spectrum peaks in at a point between blue and green. Such people can perceive the difference between a blob of light from a bluegreen laser and one made from the mixing of the light from a blue laser with a green one (something we mere trichromats can't). Most of the people who have this mutation don't know they have it, and scientists find them by looking for a specific genetic disease in men - in their fathers and brothers, for whom the same mutation has pathologic effects instead of interesting quadchromatism. Darn, we really need an article about this (or we have it, and I've not found it yet). -- Finlay McWalter | Talk 18:55, 9 December 2005 (UTC)
I believe you are looking for tetrachromat. There's pentachromat, too. -- Natalinasmpf 22:54, 9 December 2005 (UTC)
Thanks. It's impossible to google for things when you don't know what they're called, but armed with tetrachromat I found a rather preliminary thing about women (well, a woman) with tetrachromatism: http://www.cs.utk.edu/~evers/documents/tetraChromat.txt It seems the affliction the males have is just a special kind of colour blindness, which isn't as dramatic as I remember. -- Finlay McWalter | Talk 00:09, 10 December 2005 (UTC)
Early cataract (?) treatments, IIRC, involved removing the lens and replacing it with an artificial one made of polymethyl methacrylate. This had the same optical properties with regard to visible light, which is why they used it, but was co-incidentally transparent to some UV; as a result, the patients were able to make out UV lights. This proved very useful - a couple found a job in wartime, reading "invisible" signal lamps on dark coasts... Eventually, it became common practice to treat the new lens with a UV-opaque coating, to prevent this (UV isn't very good for the retina) and eventually changed to a different material.
The retina can see the near-UV okay (at least in some people), but the lens cuts it out, so as Bob says above the variation in sensitivity between individuals is irrelevant, because that light just can't reach you to be seen. Shimgray | talk | 17:13, 10 December 2005 (UTC)

Edible Seeds- including Bitter Almonds[edit]

I wish to make an old Italian cookie recipe that calls for 'Bitter Almonds', any suggestions for substitution?

Do you have any idea if apricot kernels can be a substitute, and/or are they also illegal in the U.S.?

Last question, in my search I have found information explaining that these two things, bitter almonds and apricot kernels, can be toxic. Are the seeds of apples, pears, grapes...things commonly sold in stores also toxic if eaten in quantity, and if so, what quantity?

Thank you in advance for any help in answering these questions.

MRI

Both bitter almonds and apricot pits (and other seeds of the genus Prunus) contain amygdalin, which can decompose into hydrogen cyanide when acted upon by certain acids or enzymes. Bitter almonds (but perhaps not apricots?) contain such an enzyme, so they contain free cyanide, according to our article Almond as much as 8%.
Amygdalin was actually explored, under the name laetrile, as a cancer treatment (the cancer cells have more of a certain enzyme that breaks down the amygdalin into cyanide, killing them), but it wasn't shown to be effective enough. So, it might kill you, but it might stop you from getting cancer.
I don't see how apricot kernels could be illegal, because there's one in every apricot, but IANAL. Apple, pear and grape seeds should not contain any amygdalin or cyanide because they are not from the same genus, but for the same reason, they might not taste or smell the same. Cyanide itself has an unmistakable almond smell.
Maybe you could substitute regular old sweet almonds? —Keenan Pepper 02:47, 10 December 2005 (UTC)
Alternatively, you could make them with authentic bitter almonds or apricot pits, but watch out for the symptoms of cyanide poisoning like shortness of breath or rapid heartbeat, and keep the number of a poison control center handy. —Keenan Pepper 03:00, 10 December 2005 (UTC)
IIRC, the recommendation here in Sweden (where bitter almonds are available) is not to eat more than one of them a day, to be sure not to get poisoned. (insert medical disclaimer here, I'm not sure). Also, I would guess sweet almonds are the best substitute for bitter ones, if you don't really have the choice to use bitter ones. I'm not sure what apricot kernels taste like, but sweet almonds are probably closer than them... TERdON 01:32, 11 December 2005 (UTC)
Actually you would have to consume a great deal of bitter almond kernels to get cyanide poisoning to the extent that it would seriously harm or kill you. Having consumed them myself I felt no ill effect from eating over a dozen kernels at a time. The only time that you can reliably induce cyanide poisoning is from eating a lot of kernels. According to http://www.botanical-online.com/alcaloidesametllerangles.htm the maximum recommended adult dose is twenty. Having taken ~ 500 and survived (albeit with treatment) I suspect that the hype exceeds the toxicity, also I have come to wonder if the onset of localised cyanide poisoning slows the digestion of the kernels, and therefore the release cyanide salts to limit poisoning in a negative feedback system. What would be more interesting would be to remove and isolate the HCN salts into a purer form of cyanide (potassium or sodium) which would then be lethal.

the psychological term for believing that one is satan....[edit]

i'm doing a psychoanalysis of a character in a play and he believes that he is satan... i need the term for such a delusion. please help. thanks.

Delusions of grandeur? Tzarius 22:23, 9 December 2005 (UTC)
Not sure if there is a term specifically for this type of delusional disorder. Try Narcissistic personality disorder.--
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 22:32, 9 December 2005 (UTC)

thanks you guys..

wave mechanics and my handheld radio set[edit]

I have a little hand-generated, solar-powered, battery operated radio. (It's one of those "survival radios".) It's quite portable in my room. However, I notice that it's very susceptible to changes in reception. Plane flies by (at about medium-low altitude) - some noticable interference - I actually heard a few seconds of muffled talking when it was supposed to be classical radio! But that's not the main thing I'm interested about. Apparently, if I put my hand on it, it might either help it, (louder), or soften it immediately. If it's sunny, it will change frequency (it's analog) to a higher one, but drop in volume - if it is night-time, it will drop in frequency, but raise in volume. If I touch it, it will either drop or raise in volume, or either both remove or add static. It's so very fickle. I have found there are certain intervals. If I walk away - it might become softer. I walk some more, it becomes louder. I walk away more, it becomes very loud - then very soft, then very loud, then very soft again (as distance). The intervals are about roughly a cubit (which it itself differs but that is just the idea of how long it is) - is that roughly how long radio waves are? I know some are kilometres in length but I haven't checked the EMF scale recently. 1-10 metres sounds about right, although I'd say it would be closer to a metre. I was wondering if my body was affecting the amplification or resonance of the incoming signal. Note that most experiments I've done with this is linear - I have not brought measuring tape, not tried experimenting in the second or third dimension (in the sense of making detailed observation) - although I've noticed effects. I *know* it has something to do with wave mechanics. I just don't know how my body is affecting the resonance and harmony of the incoming signal. -- Natalinasmpf 20:21, 9 December 2005 (UTC)

Just a point of clarification, but Wave Mechanics is something very different from from what you're describing, Modulation, seems more like what you're looking for--Aolanonawanabe 01:56, 13 December 2005 (UTC)
  • Well I understand that sort of stuff is mighty complicated. But there's some purty pitchers (interactive applets) at this here site: [23]. You'll probably only need the first couple for wave mechanics, there's a whole bunch of topics covered there. Tzarius 22:28, 9 December 2005 (UTC)

weather[edit]

What are you doing when you are measuring air pressure?

When you are measuring air pressure, you are effectively measuring the weight of the air column above you. For more information, see Atmospheric pressure. EWS23 | (Leave me a message!)

December 10[edit]

Online gaming kills human[edit]

A man in South Korea died after playing computer games online for 10 days.

Medically speaking , what does a man who died after playing online games for X days actually die of? Ohanian 00:01, 10 December 2005 (UTC)

Maybe exhaustion. --Think Fast 00:22, 10 December 2005 (UTC)

Actually there were countless such deaths in many Asian countries and the death toll is still growing. The cause of death of many victims can be very similar to the so-called "economy class syndrome" or "karoshi". Prolonged gaming in an internet cafe or "LAN Gaming Center" where the air quality can be very poor may lead to cardiac arrest and renal failure. Anyway, addicted gamers usually don't give it a damn. Gaming for profit actually becomes a small industry in China. -- Toytoy 01:20, 10 December 2005 (UTC)
I'd say exhaustion played a big role. Did the guy eat properly and did he go to the toilet? I'd say lack of enough food and drinks for 10 days could contribute as well. Not going to the toilet could stop his body from cleansing itself from harmful products. - Mgm|(talk) 12:48, 10 December 2005 (UTC)
Well, that answers a question I always had. I thought that would make you explode. --jpgordon∇∆∇∆ 22:29, 10 December 2005 (UTC)
It is imaginable that someone might die of uremic complications of complete physical obstruction of the urethra or bladder within 10 days, but not imaginable that he would have continued to play games nor that he would not have involuntarily urinated or defecated long before that. I think a pulmonary embolism is not a bad guess, but the sleep deprivation may have had more to do with it than the immobility. The cause of death isnt obvious. alteripse 23:29, 10 December 2005 (UTC)

Tuned Length Exhaust Systems In Four Stroke Internal Combustion Engines[edit]

What is the theory and how can one calculate the length of exhasut system downstrean of the manifold or header for maximum (or optimum) power delivery in a naturally aspirated four stroke internal combustion engine? This question also relates to the positioning of crossover pipes in systems with two exhaust pipes. A full answer to this question would cover at least the common four, six and eight cyliner engine configurations.

Can anyone out there help? 203.213.7.132 04:24, 10 December 2005 (UTC)

I think These guys can help. The problem is that it's a very complicated thing to model, the math involved is rather intense. In a 4-stroke engine, you have the exhaust valve(s) opening on a regular basis, from different cylinders. As each one opens, it releases a lot of pressure which in turn compresses the air in the exhaust system to its elastic peak, and the air then gains momentum as it lunges outward toward the exit. There is a brief moment when there is actually a drop in pressure, at a certain point in the pipe, due to this momentum. It travels like a massive sound wave, the pressure building and cascading outward. If the exhaust pipes are arranged in just such a way, this effect (known as Scavenging, a stub article sadly) will cause the pressure in the exhaust system to drop at the right point just as the next cylinder is ready to open, so that the exhaust gains momentum on its way out and creates an even stronger wave for the next cylinder. This is a basic rundown, the actual considerations for an exhaust system are many, from cam timing, header size and arrangement, total length to muffler, muffler design, and H-pipe or X-pipe design (often only done for efficiency and aesthetic reasons). Its important to remember that any exhaust system is merely a balance between power optimization and aesthetic efficiency (sound deadening), since for extreme power applications the exhaust is deleted from the car allowing the most flow possible. --Jmeden2000 02:33, 13 December 2005 (UTC)

determining if stdin is a file or a console[edit]

I am writing a C++ utility that takes its input from the command line. So when someone types

myprogram < input.txt

it works fine. However, I want the code to be able to tell when someone has just typed

myprogram

so that it can print an appropriate help message. However I can't work out how to tell whether cin is attached to a console or a file. How do I do this? Thanks Dmharvey 04:29, 10 December 2005 (UTC)

You check the file descriptor with isatty. -- Finlay McWalter | Talk 04:43, 10 December 2005 (UTC)
Here's the C code (I've no idea if C++ ridiculous io streaming whatnots have a manipulator that does the same):
 #include <unistd.h>
 int main(){
   if(isatty(0))
     printf("tty\n");
   else
     printf("pipe\n");
 }
-- Finlay McWalter | Talk 04:47, 10 December 2005 (UTC)
  • I'd use _isatty(_fileno(stdin)) to be sure, but basically the same idea. Likewise, I've no idea if the C++ cin/cout stuff works differently. (printf for ever!) --Bob Mellish 04:55, 10 December 2005 (UTC)

It's really unholy in C++. Check out this "Hackers Lament". --jpgordon∇∆∇∆ 05:05, 10 December 2005 (UTC)

Thanks so much peoples. I checked out the "Hackers' Lament" -- it's pretty hardcore. I think the simpler solutions will do just fine for what I need. Dmharvey 05:27, 10 December 2005 (UTC)

Microsoft Outlook[edit]

I have just bought a new computer with Windows XP Media Center as its operating system. I also installed Microsoft Outlook 2003 on this computer.

How can I move the contacts, journal entries, notes, tasks, etc. to this new computer from my old computer? My old computer is also a desktop with the Windows XP operating system. Of course, my Outlook stuffs on the old computer are on Microsoft Outlook 2003 as well.

I have an external hard drive (Maxtor) and rewritable disks; I don't have a cable to use the Files and Settings Transfer Wizard; I have got USB cables, though. Can someone enumerate the steps?

--John Doe on 9 December 2005

  • I believe the F&ST Wizard has "removable media" as one of it's options, so you should be able to just use it to save the settings to your external HD, and transfer them that way. --Bob Mellish 05:06, 10 December 2005 (UTC)


Thanks. It did not work; maybe I don't know how to use my external hard drive properly. Right now, both of my computers have Microsoft Outlook 2003 and the e-mails are working. Is there an easy way to send the 100+ contacts from the Outlook on one computer to the Outlook on the other computer? I don't have a PDA to synchronize it with the old computer and then sync the new computer with the PDA.

You could e-mail the contacts to yourself. --Nelson Ricardo 17:04, 10 December 2005 (UTC)

see[edit]

What do they mean by "see" in this snippit from the google article: Position: name, age, compensation in USD (as of June 2005)

CEO: Eric E. Schmidt, 50, $1 see [12] CFO: George Reyes, 51, $781K President of Technology: Sergey Brin, 31, $1 see [13] President of Products: Larry E. Page, 32, $1 see [14] Sr. VP of Worldwide Sales: Omid Kordestani, 41, $572K VP of Corp. Development, Secretary and Gen. Counsel: David C. Drummond, 42, $776K I think this might be a table of earnings after the IPO. --Shanedidona 05:01, 10 December 2005 (UTC)

  • "See" as in "see the following link" (the numbers in the square brackets) to explain why that person's salary is $1.00 this year. --Bob Mellish 05:09, 10 December 2005 (UTC)
  • And as for what it means, if I recall, Brin and Page both decided to take $1 as salary as a gesture of their faith in the company — all of their income is through stock holdings, so if the company went down the tube they'd have nothing. Or something like that. --Fastfission 15:05, 10 December 2005 (UTC)

heliocentric orbit of moon[edit]

we know that the heliocentric orbit of earth is an ellipse. what is the heliocentric orbit of earth's moon and is it a periodic or aperiodic orbit? dhtcpalyer

The Moon orbits in an ellipse around the Earth, but its period is incommensurable with that of the Earth's orbit around the Sun, so in relation to the Sun it traces out a weird loopy path that doesn't repeat. —Keenan Pepper 07:14, 10 December 2005 (UTC)
Well, I bet that if you look over a long enough period, it will repeat itself. Unless you measure really precisely, but then if you measure really precisely, nothing ever repeats itself (on this scale). Sorry about being such a nitpicker :) . And while I'm at it, can this really be called an orbit? DirkvdM 20:54, 10 December 2005 (UTC)
Good point. Nothing ever exactly repeats, it just gets close to repeating at some period, and then that correspondence drifts off and comes back around so it's better approximated by a longer period, and the whole thing is determined by the continued fraction of an irrational number. Isn't that neat? —Keenan Pepper 05:16, 11 December 2005 (UTC)

An interesting factoid is that, despite being a satellite of the Earth, the Moon's orbit around the Sun is still convex, i.e. it always curves towards the Sun, never away.[24] This, and the fact that there are about thirteen sidereal months in a tropical year, suggest that the Moon's heliocentric orbit should resemble a rounded triskaidecagon — although, as stated above, the figure isn't quite closed and will form a spirograph-like pattern over several years. In practice, however, the distance between the Moon and the Earth is so much smaller than their distance from the Sun that even the Moon's heliocentric orbit is very close to circular. —Ilmari Karonen (talk) 12:46, 11 December 2005 (UTC)

I understood that the Moon doesn't rotate about the Earth, but that both rotate around their common C of G; however, since this is well inside the Earth, Luna appears to rotate around the Earth. Add in the fact that the Earth rotates around the Sun and you may well observe retrograde motion. Alphax τεχ 07:52, 12 December 2005 (UTC)
Yes, but the Moon is only about 1% of the Earth's mass and their center of mass is actually inside the Earth. —Keenan Pepper 20:37, 12 December 2005 (UTC)
Oh right, you said that. Sorry I can't read. =P —Keenan Pepper 20:38, 12 December 2005 (UTC)


As the distance between the earth and moon is increasing, the annual path around the sun should always increase, right? I would imagine that it never repeats ever.

Patents or Copyrights?[edit]

How come the Adobe Acrobat 7.0 Standard has about 20 patents on the bottom of its box, yet Microsoft Excel or the Windows XP operating system are only copyrighted? Shouldn't all softwares be either patented or copyrighted?

--John Doe

In the U.S., software can be protected by copyright, patent and trade secret as well. Copyright protection is mainly used to against piracy. Software patents and trade secrecy are used to keep competitors from copying an inventor's solutions. Trade secrets may include many undocumented features. Adobe is actually a holder of lots of software patents. You can visit the USPTO patent database and input "Term 1: Adobe" and "Field 1: Asignee Name" and see for yourself.
See also: Software patents under United States patent law. -- Toytoy 06:28, 10 December 2005 (UTC)
  • Would it be possible and beneficial for Microsoft to obtain patents for the Windows operating system? --John
    • Aren't very simple, almost trivial, things, like double clicking on an icon, patented in the United States? I have sometimes thought I'd file a patent for branching instructions in programming languages. — JIP | Talk 10:02, 10 December 2005 (UTC)
  • You can only patent novel solutions that help people in someway which have not been invented before. They could've patented the windows layout when they created it, but now other OS systems use it, so double-clicking and the like can't be patented. Clicking is related to a mouse, not the software. - Mgm|(talk) 12:51, 10 December 2005 (UTC)
    • But there are plenty of frivolous patents related to computer software. Because such actions can be described in purely functional terms rather than necessarily referencing any existing technology, they seem ripe for this sort of thing. See for example Amazon.com's 1-click patent (clicking a link once with a mouse allows you to purchase the product! so innovative!), or SBC's attempt to cash in on a patent for HTML frames. --Fastfission 15:02, 10 December 2005 (UTC)
  • Microsoft have lots of patents. Far too many to list on the box. Here are some that can be licenced: http://www.microsoft.com/mscorp/ip/tech/. They aren't under any obligation to tell you about them. But, if you accidentally copy any patented idea or invention, you can be sued. Really, Adobe are just being helpful by drawing your attention to patents. I guess. Notinasnaid 13:38, 10 December 2005 (UTC)
  • Just a note: Software patents don't just keep competitors from copying an inventor's solutions, they also prevent people who independently developed the idea from using it. Ojw 14:26, 10 December 2005 (UTC)
    • Which is exactly why it's so vehemently opposed by those who value digital freedom. ;-) -- Natalinasmpf 14:53, 10 December 2005 (UTC)
    • Exactly. Thankyou, Natalinasmpf! Ojw 18:45, 10 December 2005 (UTC)

Oh, open source software, ie. those of the GPL, Free Software Foundation, et al tend to oppose software patents. So no, all software shouldn't be patented, some of their writers don't want to. -- Natalinasmpf 18:24, 10 December 2005 (UTC)

New low cost versions of Windows XP and Vista[edit]

I read somewhere that the future low cost versions of Windows would be able to run only three applications at a time compared to any number of applications other standard editions can run. I just want to know why such a move by Microsoft? >Is it technically not possible to create such a software Or >Is it a canny move by microsoft so that people who could afford standard versions of Windows will not buy low cost versions?

While I don't have any links to the version right now, I do remember the discussion you're talking about, and it seemed to be in response to African schools deciding to use Linux-based operating systems (for various reasons: cheaper software, better software, able to use cheaper computers, and no danger of "we're not supporting that any more, buy the new version!").
e.g. there were schemes like the $100 laptop project which are linux based and in danger of becoming quite popular. I imagine Microsoft didn't like the idea that a generation of children would grow up to be experts at using a non-Microsoft system.
The software wouldn't replace any "low cost" Windows (e.g. Windows 98, Windows XP Home) that you can buy here, it would be a completely new product, intentionally crippled to avoid competing with anything sold in developed countries, and aimed squarely at African schools.
The obvious question is why would somebody used it when they can get something like Ubuntu Linux (which is developed by an African, b.t.w.) for free, which is so powerful that many people are using it as an alternative to Windows XP Professional or Windows 2003 Server
The software you're referring to is called the starter edition (see our articles, XP and Vista). In addition to being aimed at emerging markets (mainly the East/Southeast Asia, but also Africa), not only as a way to fight open-source OSs (such as Linux), but also against pirated copies of Windows. Piracy is rampant in many of the markets targetted, and Microsoft thinks that one of the reasons is the high cost of Windows. It's of the opinion that many of the users in these areas have no need for the advanced features of a 'full' version of Windows, so they're selling them a severely stripped-down version more cheaply. Of course, they don't want to impact their profit margins in the wealthier parts of the world, so this Starter Edition won't be available in wealthier countries. — QuantumEleven | (talk) 21:57, 10 December 2005 (UTC)

Impact of a Photon[edit]

The formula for force of an impact is the well-knowen F=ma. A photon has no mass, but it can impact with measurable force. However, it accelerates to the speed of light instantly. Therefore, it has infinite acceleration. The wikipedia article Infinity states that 0 times infinity is undefined. How can a particle have undefined force. Please help. Thanks 216.209.153.14 14:11, 10 December 2005 (UTC)Max

With the example of the photoelectric effect, whether the photon is able to move something or not depends on its frequency. Various other properties such as polarization, amplitude and other properties of a photon might be a factor. Because of the entire anti-classical nature of wave-particle duality, the classical definition of F=ma does not fit in, and there is no 1-1 correlation between mass, acceleration and the properties of light/photons, although these properties will factor in towards whether a photon has enough "force" (in the now technically incorrect sense of the word) to knock out an electron. -- Natalinasmpf 14:59, 10 December 2005 (UTC)
Photons are not little balls which hit something and bounce off. When a photon hits something, it is absorbed by an electron (usually) and it is entirely converted into energy. In fact, you can think of a photon as a little packet of electromagnetic energy. F=ma is not involved. —Keenan Pepper 17:22, 10 December 2005 (UTC)
216, if you really want to think about it - mass is energy, so it's not even undefined anyway. -- Natalinasmpf 20:02, 10 December 2005 (UTC)
F=ma doesn't play nice with relativity or quantum mechanics, so you can't use it for photons. The equations to describe its motion are, unfortunately, rather complicated. -- SCZenz 20:08, 10 December 2005 (UTC)
Or if you're really brave, statistical thermodynamics, which is apparently a stub, but the interwiki links have interesting content--Aolanonawanabe 03:44, 11 December 2005 (UTC)
I also thought 0 * infinity was indeterminate, not undefined? \lim_{x \to 0} x \cdot \frac{a}{x} = 0 \cdot \infty = a, so 0 \cdot \infty can be whatever a can be? --AySz88^-^ 14:16, 11 December 2005 (UTC)
A sop for those of us who can't go into the full details of quantum electrodynamics with our students is to admit that while a photon has no mass it does have momentum, because it has energy. Physchim62 (talk) 15:30, 11 December 2005 (UTC)

How can something be scientific?[edit]

If it's unobservable, invisible, and totally unprovable? If so why does science always rush to the defense of Darwinists? Do they have ulterior motives? Political motives? Are they being paid off? Don't want to lose their cushy 'science' jobs so they spread this pointless banter to make their side look like it ears a living?--152.163.101.12 15:08, 10 December 2005 (UTC)

  • Some people are just narrow minded hypocrites, don't let them get under your skin so easily, they can keep pushing their evolutionary theory, and intelligent people every where will keep pushing it back in their faces, 'scientists' ha, some people watch too much TV--Ytrewqt 15:26, 10 December 2005 (UTC)
  • Evolution is not "unobservable, invisible, and totally unprovable". It is well supported by a wealth of evidence. It is science, it's at the core of all biological sciences. And science jobs are not cushy - earning $30,000-$60,000 a year after 7 years of grad school and as a postdoc is not cushy. Guettarda 15:39, 10 December 2005 (UTC)
  • Why do Christians insist upon the existence of some unobservable, invisible, and totally unprovable god? why must they inflict their mythology upon everyone else and cause hatred in the world? Why are they afraid of science? --Nelson Ricardo 17:00, 10 December 2005 (UTC)
    Because of the incredible amount of evidence in favour of the existence of God. It's people like yourselves who claim to know what the other side thinks but in actual fact have no idea whatsoever that cause the hatred. Alphax τεχ 07:59, 12 December 2005 (UTC)
  • Just because something is invisible and can't be directly observed doesn't mean it's impossible to know anything about it. Do you believe in quarks? You can't observe an individual quark, almost by definition, but the quark model has predicted things later shown to be exactly right. —Keenan Pepper 17:15, 10 December 2005 (UTC)
Nothing is provable (outside mathematics, where that only works because you create the world in which you want to prove things). I don't know what you are thinking of when you say 'Darwinists', but evolution (if that's what you're thinking of) is not unobservable. Fruit flies are very popular for genetic research and one reason is that is that they have such short lives. So in the course of one year (let alone one lifetime or the lifespan of science itself) one can go through many generations, enough to see evolution at work. But bacteria are even better for this because their generations are extremely short. Why do antibiotics not work anymore where they did before? Because the bacteria have evolved to survive in an environment with antibiotics. On a much larger scale, though, domestic animals are a nice example of evolution put to work for humans. In stead of letting nature do the selecting we've started doing it and lo and behold we can create our own species. Hmm, am I exaggerating now? Of course in the end we could create new species, but have we technically? Domesticated cows can still create offspring with wild ones (ehm, bulls, I mean :) ). Any better examples? DirkvdM 21:07, 10 December 2005 (UTC)
Dogs were created from wolves. We made huge amounts of variatons on them, too... TERdON 01:41, 11 December 2005 (UTC)
  • One criteon that makes something scientific is measurability. Does Darwin's evolution have more measurements and numerical approximations or traditional religious accounts of creation? Lord Kelvin (1824-1907) astutely stated:

:"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of Science, whatever the matter may be."

--John Doe

  • Also, radio waves are invisible to the naked eye, yet they can be detected and measured with instruments unlike ghosts.

--John Doe

  • We turned our backs on god when we started to embrace science. When science can no longer provide us with the answers we seek then we will turn to face god again. Such is the human need to find answers to life, the universe, and everything. But for the time being I'll stick with the science thing.--Eye 00:00, 11 December 2005 (UTC)
  • The original question makes me wonder "Does this person know anything about the data sets that are the basis for the theory of evolution?" Such strong statements about science are worthless unless you are up to speed on the topic. I suggest you go and do research before making assertions that expose your own ignorance of the topic at hand. Actually there is a good article in wikipedia, evolution, why don't you read it? Then come back and rephrase your question. David D. (Talk) 00:45, 11 December 2005 (UTC)
  • What science is depends on whether you're in Kansas or not. In Kansas, something is "scientific" if it gives an explanation. In the rest of the world, science is searching for natural explanations of observed phenomena, with these explanations backed up by data. Parsimony is good too.--YixilTesiphon Say hello Consider my Wikiproject idea 00:51, 11 December 2005 (UTC)
Don't you guys know anything about Don't Feed the Troll? --Fangz 01:13, 11 December 2005 (UTC)
In these cases the parody is impossible to distinquish from the real thing. David D. (Talk) 01:19, 11 December 2005 (UTC)
  • If you ask a scientist about something that hasn't been discovered, then your answer will be, "I don't know." If you ask a religious scholar about something, then you always get an answer. So then you might say, "What is the catch?" It is quite simple: Religion is a system of uproveable statements. Bertrand Russell

--John Doe

Troll or not, the question "How can something be scientific?" is an extremely good one. It's not always obvious how science actually "works", and some of its most important aspects are not widely known. Our article on the Scientific method contains some good discussion, but needs more work.
Besides observability and testability, another vitally important aspect of science is an element of doubt. Science is always supposed to be able to question its assumptions and its prior results, is always supposed to be open to new explanations, is never supposed to take anything on faith. (One might note that there are other modes of thought with just about exactly the opposite traits.) Now, it's true, scientists are people too and don't always manage to uphold these lofty goals perfectly (which is to say, there is unfortunately more than a little inertia and politics and fashion and unquestioned faith when it comes to the day-to-day practice of science), but good scientists do at least try, and over the long run, scientific truth will out.
Some might ask, "if science is really open to new interpretations, why is it so opposed to Intelligent design?" But what you have to realize is that ID is not some brand-new idea that was first hatched in Dover, PA a few months ago. The "intelligent design theory" we've heard so much about recently is merely a rehashing of several ideas which have been debated (in stodgy, acedemic style) in the evolutionary biology community for decades. (Indeed, William Paley was musing about a watchmaker -- the same watchmaker Dawkins discusses in his popular book -- over two centuries ago, in 1802.) Those ideas have been put forth, held up, analyzed, dissected, explored, elaborated, and discussed at great length. Some have resulted in changes to the current state-of-the-art in evolutionary "knowledge", some have been rejected. They have not been rejected out-of-hand, and if in their "renaissance" during the Dover trial they seemed to be rejected out-of-hand, it was only out of exasperation given the wholly unscientific nature (the courtroom drama, the media circus) of the reemergent "debate".
Steve Summit (talk) 19:31, 11 December 2005 (UTC)

meaning because we are arrogant enough to think our ignorance makes us clever, religionists interpretation) that make religion look like childish gibberish compared to the growing adulthood of science. Darwinism has testable hypotheses, and creates a theory with explanatory power; without dwelling on the point, that would be above the head of a theist anyhow,

Jesus would follow the golden rule and respect both views of how things came to be. Scientific and metaphysical are mutually exclusive concepts. People who are trying to be like Christ should make note of his methodical use of parable: Doesn't it stand to reason that biblical texts can retain or even improve a person's faith when they can be read and interpretted with the same spirit of "student seeking spiritual nourishment"; as opposed to narrow, my-way-or-the-highway minded, hypocritical "literal interpretation?" More than all else, Jesus railed against hypocrites. Even the most pious should bear witness to the scientific method's inherent checks for fraud or deceit. What does your spiritual guide offer?

Science is science because it always starts from a position of agnostic ignorance, religion always starts from singular arrogance which explains why such a nonsensical position can be proposed and the devious nature of religion to try to mask a ludicrous statement as a question. IF ONLY theists would spend longer trying to create a testable hypothesis for their claims and less time trying to undermine the scientific theories (yes that is -theories- the scientific word not the - oh let's deliberately misinterpret this word with the colloquial meaning because we are arrogant enough to think our ignorance makes us clever, religionists interpretation) that make religion look like childish gibberish compared to the growing adulthood of science. Darwinism has testable hypotheses, and creates a theory with explanatory power; without dwelling on the point, that would be above the head of a theist anyhow; religion doesn't.

What does Pigeon Tech mean?[edit]

  • No idea; some context would help. But it might be an allusion to homing pigeons. --Fastfission 16:50, 10 December 2005 (UTC)
You don't mean Pigeon Rank, do you? smurrayinchester(User), (Ho Ho Ho!) 22:28, 10 December 2005 (UTC)

the application of computer in mathematics with references[edit]

...That's not a question. It sounds more like an essay topic to me. —Keenan Pepper 17:17, 10 December 2005 (UTC)
I'm quite tempted to cite Template:dyoh, as well. -- Natalinasmpf 07:27, 12 December 2005 (UTC)
That doesn't have references, though. How about ENIAC? ᓛᖁ♀ 07:15, 12 December 2005 (UTC)

Conservation of Energy[edit]

When a proton transforms into a neutron, it goes through the process: P -> N + e+ + νe. P=Proton, N=Neutron, e+=Positron, and νe=Electron Neutrino. When a neutron becomes a proton, it goes through the process: N -> P + e + \bar{\nu}_e. e=Electron and \bar{\nu}_e=Electron Antineutrino. So P -> P + (e + \bar{\nu}_e) + e+ + νe by substituting P + e + \bar{\nu}_e for N. P + (e + \bar{\nu}_e) + e+ + νe = P + (e + e+) + (νe + \bar{\nu}_e) = P + ENERGY (The particles and antiparticles annihilate). Doesn't that violate the conservation of energy? 216.209.153.144 17:22, 10 December 2005 (UTC)Thanks - Max

I cleaned up your markup for you; hope you don't mind. —Keenan Pepper 17:37, 10 December 2005 (UTC)
As for the answer to your question, the decay of the neutron happens spontaneously and energy is released, but the decay of the proton is not spontaneous and requires energy input to occur. That's why the hydrogen nucleus (a single proton) is stable. See beta decay. Energy is always conserved. —Keenan Pepper 17:42, 10 December 2005 (UTC)

Nuclear Fusion[edit]

This is a reply to the above question. If P + ENERGY = N + e+ + Ve, then wouldn't P + P + P + P -> He4(or P + P + N + N) + 2e+ + 2Ve be endothermic, not exothermic (P=Proton, N=Neutron, e+=Positron, and Ve=Electron Neutrino)? Can someone help? Thanks 216.209.153.144 18:27, 10 December 2005 (UTC)Max

Fusion of hydrogen into helium is very exothermic, because of the strong nuclear force, which you are not taking into account. Two protons changing into two neutrons would be endothermic, but the energy released when the two protons and two neutrons fuse into a helium nucleus far outweighs that. —Keenan Pepper 19:07, 10 December 2005 (UTC)
Remember, they don't call it the "strong" force for nothin'! —Keenan Pepper 19:12, 10 December 2005 (UTC)

Google Wi-Fi[edit]

Recently, Google is offering free Wi-Fi in Mountain View in California. Is it supported by advertisements? If yes, then what type of advertisements are they serving?

I'd guess their standard average "contextual text ads" (aka. data mining), if it's true. Alphax τεχ 08:03, 12 December 2005 (UTC)

what is bit snd byte kbps and Mbps[edit]

You may want to write out your question more fully in the future (I'm having to guess what you mean...). In my opinion, you mean bit and byte by your first and third items - the articles on these subjects are pretty good. kbps and Mbps and units of data transmission rate - the speed at which information is transmitted. They stand for kilobit per second (1000 bits per second) and Megabit per second (1000000 bits per second). As for snd, I'm afraid it could be any number of things. If you saw it in the context of computers, it could be an abbreviation of send... — QuantumEleven | (talk) 22:05, 10 December 2005 (UTC)

I thought "snd" was a typo for "and"... - Akamad 22:16, 10 December 2005 (UTC)
Maybe it stands for sound, and (s)he want to know something about the bitrate of audio files? —R. Koot 02:00, 11 December 2005 (UTC)
Snd is a powerful sound file editor that can be customized and extended using the Scheme programming language.[25] I definitely think it was a typo though. =P —Keenan Pepper 05:07, 11 December 2005 (UTC)
I too feel Snd in this context is a punctuation typo, SND means SEND in the IBM AS/400 operating system. Basically 95% of the commands in OS/400 are constructed out of 2 and 3 letter abbreviations for objects, and do what with them. SNDMSG to send a simple message for example. AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 20:54, 14 December 2005 (UTC)

Fusion and Fission[edit]

Sorry I had to post three questions in a row, but if nuclear fusion gives off energy via the strong force, then why does nuclear fission also give off energy. Wouldn't the opposite process have the opposite effect? I heard that it has something to do with iron. Please help 216.209.153.92 21:42, 10 December 2005 (UTC)Max

The answer is rather complicated, but to give a greatly simplified version: Fusion of light elements (to heavier elements) gives off energy, as does fission of heavy elements (to lighter elements). Fission of a light element or fusion of a heavy element is endothermic - it requires more energy than it outputs. If you keep fusing light elements, eventually you will get to iron, at which point further fusion becomes endothermic. The same happens when you fission heavy elements - the reaction gives off energy until you get to iron, at which point is becomes endothermic.
The reason for this strange phenomenon is that, for elements lighter than iron, the binding energy in the nucleus increases as the element gets heavier, so that energy is released in the fusion reaction. As you go down the periodic table, the binding energy increases until you get to iron (the most stable nucleus, with the greatest binding energy), and then it starts decreasing again (so fissioning heavy elements also moves from less bound nuclei to more bound nuclei, releasing energy).
And there is nothing wrong with asking questions - ask away! :) — QuantumEleven | (talk) 22:16, 10 December 2005 (UTC)
So will the Universe end as one big lump of iron? DirkvdM 21:21, 11 December 2005 (UTC)
More or less, of course a zero potential system would't have enough energy to form 'clumps' so probably a better word for it would be an infinitely dispesed cloud of inert metal at temperatures near 0K.--Aolanonawanabe 01:48, 13 December 2005 (UTC)

Kaonic Hydrogen[edit]

If you were to create larger atoms, like carbon, with kaons instead of electrons (like kaonic hydrogen), would there be no analogy of electron shells because kaons, being bosons, are not subject to the pauli exclusion principle? And so wouldn't molecules made form kaonic atoms be much denser than normal molecules? And wouldn't the strong force help two kaonic atoms to bond?

They probably would have many weird properties... if you could get then to last longer than a tiny fraction of a second. —Keenan Pepper 05:21, 11 December 2005 (UTC)
  • My guess would be there's a good physical reason why they have yet to be observed. --YixilTesiphon Say hello 00:30, 12 December 2005 (UTC)
They have been observed (created in the laboratory); they just have extremely short lifetimes, probably due mainly to the instability of kaons. Our article on exotic atoms suggests kaons still form atomic orbitals. ᓛᖁ♀ 00:52, 12 December 2005 (UTC)

Exotic atoms[edit]

Exotic atom states the nucleus of mesonic atoms is bound to orbital mesons by the strong interaction. Should this be the nuclear force instead? ᓛᖁ♀ 00:59, 12 December 2005 (UTC)

The "nuclear force" and the "residual strong interaction" are the same thing. —Keenan Pepper 01:09, 12 December 2005 (UTC)
That's what I thought; thanks. The article hadn't made it clear that it was talking about the residual strong force. ᓛᖁ♀ 01:28, 12 December 2005 (UTC)

...By the way, what would the exchange particle be for the interaction between a proton and a kaon? ᓛᖁ♀ 01:45, 12 December 2005 (UTC)

At a distance, the interactions would be primarily electromagnetic, i.e. mediated by photons, just like between protons and electrons. However, at close range protons and kaons will also interact via the nuclear force (residual strong force, mediated by light mesons) as well as the weak force (W and Z bosons). At even closer distances the component quarks may interact via the strong force (mediated by gluons), although at this point it may no longer make sense to speak of the proton and the kaon as separate particles. —Ilmari Karonen (talk) 07:11, 12 December 2005 (UTC)
Heh, thanks. What I was really after is the mesons that should mediate the nuclear force between them; which should those be? Would they have to be kaons as well? ᓛᖁ♀ 07:29, 12 December 2005 (UTC)

Also, incidentally, should the behavior of kaonic hydrogen explain why the uudds pentaquark was seen to decay to a neutron and a kaon? ᓛᖁ♀ 07:53, 12 December 2005 (UTC)

Piggybacking computer speakers[edit]

I have 4 computers set up with a KVM. I am adding a BEEP in the programs that I will run on them to let me know what it needs me to answer a question. The problem is that I don't want to have 4 sets of speakers. So, which is best: get a 4-way splitter and plug one set of speakers into all 4? Since all have a line-in and line-out, can I jumper from one to another to another and put the speakers on the last one? It isn't just which setup makes noise. I don't want to mess up the soundcards (or speakers). --Kainaw (talk) 23:25, 10 December 2005 (UTC)

If the computers are in the same room as you, you could make your program use the built-in speaker in the computer instead? The one that is connected to the mainboard. TERdON 01:46, 11 December 2005 (UTC)
It may be too late, but there are KVM units that include audio switching. I am doubtful that you can just combine the signals with a simple splitter: that doesn't sound a good thing, even if the computers take it in turns to speak. Combining audio is of course possible, though a mixer unit. But daisy chaining line out-line in? That does sound attractive. Notinasnaid 19:03, 11 December 2005 (UTC)
I'd go beyond Notinasnaid's "doubtful" and say that trying to use a 1-to-4 splitter "backwards" would almost certainly not work properly, since you'd have four speaker outputs all trying to drive the same line to different voltage levels. I'd guess the effect would be that you'd get sound from one of the computers, but which one would essentially be random. I'd either go with daisy-chaining the line-in/line-outs, or if you want a solution which doesn't need all the computers to be on, I'd get a 4-to-1 mixer cheap off eBay. -- AJR | Talk 19:51, 11 December 2005 (UTC)

How to make an icebox?[edit]

I need to know how to make an icebox - used to keep food cool in the 19th Century by farmers in South Africa who had no electric power. It involved using charcoal. Any suggestions? --

Large ice boxes are not popular in rural/desert areas of Africa where electricity is unavailable. Instead, they use clay pots wrapped in moist cloth. The heat evaporates the water from the cloth, removing heat from the clay pot. The pots can be very large, but a walk-in icebox would be unreasonable to keep moist. --Kainaw (talk) 05:33, 11 December 2005 (UTC)

Disable windows system redundancy check?[edit]

Ever since my reformat I've been getting a system redunancy check any time I try to copy/move/download any file greater than 200MB, yes I know, I know your hard drive is bad, well it doesn't seem to be, it just seems like one of those settings that gets messed up/reset to default after a reformat.. ..is there any way to disable system redundancy checks?--Cyclic check 01:57, 11 December 2005 (UTC)

It's probably a cyclic redundancy check performed either by the filesystem or the drive controller (you've not said enough about the context of this message to make it clear which). Either way, the drive is definately bad, and you should chuck it away. There's no way to disable the CRC checks: they've at the very fundament of how data is stored on magnetic media, and they're there for a very good reason. --
It can't be the hard drive. becasue the same thing happens when I try to save/copy/download anything to an entirly different external drive, it has to be an OS thing, can I just turn it off? at my own risk?--Cyclic check 02:09, 11 December 2005 (UTC)
It doesn't really have to be the disk (especially if you have the same problem with several different ones). You could also have a problem with the disk controller. Or the RAM. Or the CPU. Or the mainboard in general. Possibly connected to high load of the computer as you don't get errors when dealing with small files. What is sure though, CRC errors mean something really doesn't work, and if you get them often something in your computer doesn't work as it should (it could possibly be the OS, but then it would be really unusally severe and I don't really think it's likely...) TERdON 02:17, 11 December 2005 (UTC)
It could be aproblem with your DMA settings of the hard drive controller. Check the device manager and turn of, or lower your DMA setting. —R. Koot 02:29, 11 December 2005 (UTC)
I had a very similary problem due completely to DMA. I fixed it by getting a proper UDMA IDE cable (one with a blue plug on the end). I know it sounds stupid (a cable is a cable), but the UDMA IDE cables have a ground-wire for each pin and that does make a difference. --Kainaw (talk) 20:54, 11 December 2005 (UTC)

Whatever your real problem is, you definitely don't want to fix it by disabling the system checks. That's like dealing with a false fire alarm by cutting the wires to the fire alarm horn, or dealing with a persistently blowing fuse by putting a penny under it. Steve Summit (talk) 18:02, 13 December 2005 (UTC)

Automatic querying[edit]

How would I go about automatically retrieving information from a website at regular intervals, more specifically, the Wikipedia statistics (number of articles, etc.)? --Borbrav 06:47, 11 December 2005 (UTC)

Me, I would write a shell script to invoke a noninteractive webpage fetcher, such as wget, or lynx -dump. I would then arrange to have the shell script invoked periodically by putting it in my crontab. I would do this under Linux or Unix. I tend to suspect none of this will be applicable for you, but since you didn't say which operating system you're using, I can't be sure. Steve Summit (talk) 18:08, 11 December 2005 (UTC)
Well, I'm running XP, so I guess a batch file would be the equivalent of the Unix shell script. However, I have no idea how to write such a program, so bit of advice there would be most useful. --Borbrav 21:30, 11 December 2005 (UTC)
Create an empty text file, and rename it to a filename ending in .bat or .cmd. Then, edit it using something like Notepad, and put in the commands you want to run, one per line, just as if you were typing them at the command prompt. If you don't already have software for automatically downloading data, I second the recommendation for wget. As for running your script at regular intervals, you'll probably find that Windows' Scheduled Tasks feature works pretty well. —David Wahler (talk) 01:25, 12 December 2005 (UTC)
Time to learn batch file programming! --Borbrav 04:15, 12 December 2005 (UTC)

bach rescue remedy, what is it?[edit]

Bach flower essence, rescue remedy[edit]

You could start by reading Rescue_remedy and Bach flower remedies. --Borbrav 07:27, 11 December 2005 (UTC)

December 11[edit]

qbasic[edit]

for instance, i created a questionnaire, and i written it in qbasic. one must run the program to see the questions. how do you save the answers the people insert?

  • You'd have to save them in and load them from a separate file. The QBasic help files should provide you with help on handling of external files. - Mgm|(talk) 11:10, 11 December 2005 (UTC)
i don't want to sound too negative, but we live in 2005 (almost 2006), do you really want to have people fill in a questionnair made in qbasic? if you are starting programming then it would be wise to do it in something that supports drawing windows and such. you could do something like this with a webpage and some scripting also. Boneyard 13:44, 12 December 2005 (UTC)
It's probably some kind of qbasic specific homework assignment or soemthing else for a CS course--Aolanonawanabe 01:44, 13 December 2005 (UTC)
Hey! I program in QBasic just for fun! As for the question in hand, you need to save them to an external file, because I'm afraid that there is no way to have them stored in memory. You should do something like this:
outFile$ = "Insert name and path of output file"
.
.
.
OPEN outFile$ FOR OUTPUT AS #3
.
.
.
PRINT #3, varToPrint$
Titoxd(?!? - did you read this?) 01:48, 13 December 2005 (UTC)

bypassing firewall[edit]

i often heard of the word firewall, i know it means it sort of get rid of the viruses and allows us to read the correct message, but what exactly is a firewall? how do people bypass a firewall?

actually, if a person filters certain webpages, and you desperately need to use that filtered website, how do you go to it? i tried using different web browsers and it seems it has no use...please tell me! i am desperate! i need to do my work in www.ibiblio.org and somehow my school administrator filtered this web!

See our article on Firewalls for more information on firewalls. Regarding your problem, there are many ways schools, goverments, etc. carry out Internet censorship. HOWTO bypass Internet Censorship is a good article with a lot of different tips and methods. -- Daverocks 10:44, 11 December 2005 (UTC)

If you want to connect to blocked sites, talk to your school administrator or connect from somewhere else (like home or an internet cafe). If you start trying to bypass this stuff you could get in serious trouble. Notinasnaid 11:18, 11 December 2005 (UTC)

Windows XP Help[edit]

How do I create access to an item from C:\Program Files on the All Programs menu of the start button on the Windows XP taskbar?

My Norton SystemWorks program is in the Program Files folder, but it isn't on the All Programs menu.

--John Doe

The "All Programs" menu is located at %userprofile%\Start Menu\Programs. %userprofile% is usually something like C:\Documents and Settings\Joe or your username. Stuff in Program Files do not necessarily appear on the Start Menu unless the installers put them there. Try putting the program in C:\Documents and Settings\Joe\Start Menu\Programs or similar. -- Daverocks 11:56, 11 December 2005 (UTC)

  • I was able to add Norton SystemWorks to the All Programs menu of the start button. However, it is not like the other programs. It is impossible to actually launch the program and start using it. When I click on Norton SystemWorks, I see sub-menu items like NSWRes.dll, readme, wgsplugin.nsi, and lots of other items with the .dll extension.

I copied Norton SystemWorks from my old computer, which is not networked to the new computer I am currently using, on an external hard drive. Then I connected the external hard drive to the new computer and pasted Norton SystemWorks in C:\Program Files. I prefer not the use my installation CD for Norton SystemWorks. Is there any method to launch the Norton SystemWorks program on my new computer?

--John Doe

You need to install SystemWorks from the original CD. Just copying the files from one computer to another is not sufficient, as there are registry entries which are not so simple to copy, and there may be configuration files which are specific to the first computer. This advice applied to most Windows software.
You should also consider whether you have a licence to run SystemWorks on a second computer. Most likely, you had a licence to run it on the first computer only, and the licence is not transferable to another one.-gadfium 00:37, 12 December 2005 (UTC)


  • Do I have a license to completely delete the Norton SystemWorks from my old computer and install it from the original CD on my new computer -- since I have a license to use the utility software on a single computer; so by deleting it on the old computer, then I will still be using the software on a single computer, that is, the new computer?

--John Doe --66.81.24.22 01:58, 12 December 2005 (UTC)

I can't tell you what your licence says. Most likely, the licence agreement for Systemworks varies from one release to another, and may have different clauses for different countries. Anyway, I don't have a copy here. You may consider that you have a reasonable moral right to delete it from one computer and install it on another, and you most likely have a legal right to reinstall it if your hard disk crashes and you replace the disk, but you probably don't have the legal right to reinstall on a new computer even though you are uninstalling it on the old one. I am not a lawyer, so this doesn't constitute legal advice. The licence agreement may make claims which limit your rights which are not legally enforceable. The safest advice is for you to consult a lawyer, but that will likely cost you more than the software is worth. It's up to you to decide what's right.
Depending on the version of SystemWorks (after 2003 if I recall correctly), you'll have to reactivate it after installation. It is possible that you won't be able to do this because the licence key is tracked and has already been used. In this case, there is probably a mechanism for you to contact Symantec and explain the circumstances of the reinstallation to get a new licence key or unlblocking of the old one.
If you are using SystemWorks primarily for the antivirus, consider using a free antivirus program instead. I've heard good things about AVG Anti-Virus.-gadfium 03:18, 12 December 2005 (UTC)

Thank you.

Newer versions of the Norton products not only come with cool stuff not on prior versions, but also
  • If you can show proof that you owned earlier version, you can get a significant $ rebate against purchase of the new version which is like an upgrade.
    • So, armed with the proof of ownership on the old computer, you can legally buy very inexpensively the latest version, which you then install on the new computer.
  • Most computer software companies are well aware of their customers periodically needing to upgrade hardware to a replacement computer, and want to keep those customers happy, and not so annoyed that they will go to a competing vendor for similar services on their next computer, so most will be happy to walk you through how to get THEIR software onto your NEW computer at minimum hassle for you and minimum cost. So any time you do an upgrade from an old computer to a new one, it can be well worth your while to contact the tech support associated with each of the products you depend upon on your old computer, to ask them whether it is legitimate under their license to move your whatever to your new computer, and if so, can they tell you how. Be sure to give details on the old and new computers like version of Operating System involved.
  • Another common scenario is people having a computer at home, at work, a portable laptop, in which they want to have much of the same software on all their computers, and they not want to have to pay full retail price each time. After all, they are ONE customer with X computers. Similarly in big business, you have an office with X computers each with one employee ... the company wants a discount or group buy. Some homes are now getting computers networked, so that multiple family members computers share some resources. Many computer software companies have deals for such customers such that you can get the same software licensed to more than one computer AT THE SAME TIME, for much less money than paying for the software for each and every computer involved. You need to contact your individual software suppliers to ask if they have such a multi-computer software license and what would be involved for you to get one. This applies to everything: Windows or other OS, Word Processing, Security, everything ... so bear that in mind if you plan to be operating two or more computers in your home or office, concurrently.

AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 21:10, 14 December 2005 (UTC)

what is platinum[edit]

See our article platinum. It is a metal element, and very valuable, much more than gold. -- Natalinasmpf 22:47, 11 December 2005 (UTC)

Walk across the Bering Strait?[edit]

Does the Bering Strait ever freeze over, so you could theoretically walk across it? This picture makes it look like the strait is covered with ice in the winter, but I'm not sure. Has anyone actually walked across it, or driven a sled, etc.? —Keenan Pepper 22:56, 11 December 2005 (UTC)

While it may be possible for it to freeze over, I don't believe it is allowed to do so due to naval traffic. It is a major seaway for oil tankers from northern Russia, Alaska and Canada. --Kainaw (talk) 22:58, 11 December 2005 (UTC)
This page [26] has a listing of various such attempts. It seems at least several have done it successfully. --Borbrav 23:07, 11 December 2005 (UTC)
Wow, it looks like some people are in the middle of crossing it right now: http://www.beringodyssey.com/ This is neat! —Keenan Pepper 23:14, 11 December 2005 (UTC)

December 12[edit]

Downloads begin quickly, then slow down[edit]

Why do my downloads begin at a relatively high speed and then progressively slow down, usually by 1 KB at a time? I'm using DSL if that has any bearing, and the last time this occurred nothing else was using my connection at the time. --Impaciente 00:11, 12 December 2005 (UTC)

It may be due to a number of factors. One possible factor is that when you click on a link, but before you find the location to put it in and click Save in the dialog box, some data has been downloaded by your computer, thus accounting for the apparently increase in speed initially. It may also be due to your ISP or other points along the way between your computer and the server slowing the connection down. Enochlau 01:52, 12 December 2005 (UTC)
Keep in mind that the "speeds" you see in KB/s are usually calculated by taking the total amount of data downloaded and dividing that by the total amount of time elapsed. An unusually high speed at the start of a download is often an inaccurate reading if data has already been downloaded with less time elapsed. This is particularly noticeable with my artificially limited 256k DSL where there is no way the speed should go over 32 KB/s, but seems to anyway sometimes at the start of a download from the inaccurate reading. The "slowing down" you are experiencing is caused by the total time elapsing at a constant rate, but the download speed being a lot slower. The actual download rate hasn't slowed down, but the KB/s reading is, as a result of naturally correcting (through time elapsed) the original misreading at the start of a download. -- Daverocks 09:44, 12 December 2005 (UTC)

microscopes[edit]

Great question! Try Microscope. --YixilTesiphon Say hello 00:33, 12 December 2005 (UTC)

What is a magnetic field made of?[edit]

Could someone please tell me what a magnetic field is made of. Wikipedia doesn't seem to say. By "made of" I mean communication between two points. Photons? Electrons? Virtual particles that come in and out of existance and "touch hands" as a way of communication? If it's a wave, what frequancy? Thanks 153.111.60.15 00:47, 12 December 2005 (UTC)

The four fundemental fources of nature (the strong nuclear force, weak nuclear force, electromagetnic force, and gravity) all form fields of potential, and each has an associated particle which mediates its force. (See List of particles). For the electromagnetic force, the force is carried by photons. Raul654 00:51, 12 December 2005 (UTC)
Also see virtual particle. Magnetic fields are "made of" virtual photons. —Keenan Pepper 01:02, 12 December 2005 (UTC)

.dll[edit]

I have read the beginnings .dll article, but I got confused. Can someone delineate to a layperson the importance and function of .dll via an analogy or another way for explaining it? I know about computer applications software and use them well, but I am not a computer scientist.

--66.81.24.22 02:06, 12 December 2005 (UTC)

.dll's or shared libraries are repositories for commonly-needed functionality, somewhat analogous to real-world libraries. A .dll contains a collection of routines that applications can "look up" as needed. They're sort of like cookbooks, except the recipes tell how to draw graphical user interface elements or how to perform specific calculations. ᓛᖁ♀ 02:23, 12 December 2005 (UTC)
(edit conflict) I think you might find the more-general concept at Shared Library (section of Library (computer science) ) better, or look at the first section in the .dll article.
Reading the article (I'm no expert on this), it seems that each DLL is a module (piece of a program) containing often-used code that can be shared among lots of programs. It saves memory because different programs that use the same instructions don't have to store those instructions over and over. --AySz88^-^ 02:26, 12 December 2005 (UTC)

Kaplan-Myers analysis[edit]

What is the Kaplan-Myers analysis? It is referred to all over the place but I cannot find a definition of what it is. Help please.

Search for "Kaplan-Meier" for better results. I don't believe we have anything here on Wikipedia to help you.-gadfium 08:02, 12 December 2005 (UTC)

The (d)inosaurs[edit]

Did gravity cause the death of the dinosaurs?—Preceding unsigned comment added by 172.205.155.127 (talkcontribs)

The Dinosaurs article has a section on extinction theories. According to that, an asteroid crash could have caused mass extinction, so in a way, yes gravity did cause the death of dinosaurs. - Akamad 10:50, 12 December 2005 (UTC)
Like if someone dropped pianos on their heads it would be blamed on gravity? alteripse 11:52, 12 December 2005 (UTC)
It would make novel defence against prosecution, but somehow I don't imagine it being a particularly successful one. Thryduulf 13:42, 12 December 2005 (UTC)

Bubonic plague[edit]

Where can I find a map of the spreading of the bubonic plague?

From our article on bubonic plague. –Mysid 13:11, 12 December 2005 (UTC)

See Black Death for map and bubonic plague. alteripse 13:15, 12 December 2005 (UTC)

Virus transcription in the cytoplasm?[edit]

I've always understood that in eucaryotes, the DNA was only transcribed in the nucleus of the cell, because the necessary transcription proteins only occurs on the nucleus. How then does a DNA virus manage to get its genome transcribed and translated? Does it carry its own transcription proteins (or catalyse its own transcription in some way), or are there such proteins available within the cytoplasm too. Or does it somehow move its genome into the nucleus?

Could provide me with a source for the answer too? I'd like to read the context and such. Thanks, Ec5618 16:10, 12 December 2005 (UTC)

  • Most likely, the DNA of the virus is attached to various proteins which seek out and enter the nucleus of the cell. Virus#Replication has more information, though it doesn't answer your question. --YixilTesiphon Say helloBe shallow 04:17, 13 December 2005 (UTC)
    • Right, thanks. That was one of my guesses. Now to find a source. -- Ec5618 08:13, 13 December 2005 (UTC)
      • It really depends on the type of virus. In the case of a retrovirus, which can modify the host DNA, using reverse transcriptase to convert its genetic material to DNA once it enters the nucleu, then uses integrase to append itself to the host DNA. -- Natalinasmpf 08:38, 13 December 2005 (UTC)
        • Yes, thank you, but how does the retrovirus get its genome into the nucleus? I understand that it enters the cell's genome, but not how it can reach said genome. I can imagine no cellular system for the transport of genetic material into the nucleus (what would be the point?). -- Ec5618 09:22, 13 December 2005 (UTC)
  • Virusses have a long needle-like tip with which they can inject their genetic material into the cell. But there's also virusses (like HIV) which remain intact as they enter the cell by endocytosis, which means they can use their needle to inject their material into the nucleus. I'm not sure how loose DNA would get in. Perhaps some channel? - Mgm|(talk) 09:33, 13 December 2005 (UTC)

I think it differs from virus to virus, but for the herpesvirus it goes as follows: The virus envelope fuses with the cell membrane and releases the virus with its nucleocapsid into the cytoplasm. The nucleocapsid then 'docks' with the nuclear membrane and releases the DNA into the nucleus. --WS 15:08, 13 December 2005 (UTC)

This link tells the story for HIV. --WS 15:12, 13 December 2005 (UTC)
Just so we can all have some sense of closure: it's true that different viruses work in different ways. Just as there are different ways for a virus to penetrate the cell membrane, there appear to be different ways for them to penetrate the nucleus.
Not all viruses have needlelike tips (indeed, some 'burn' through the cell membrane using a lipid destroying enzyme), but I suppose its possible some viruses that enter the cell through endocytosis may still carry a needlelike tip, to use them to penetrate the nuclear membrane. Other viruses may simply use channels and gates to allow the DNA to be absorbed into the nucleus.
I'm afraid that for most viruses the mechanism is unknown or unclear: HIV (according to the above link, thanks WS) "Although the exact mechanism that HIV uses to transport its genetic cargo into the cell nucleus is still unclear, viral protein R (VPR), which is carried by HIV, may facilitate the movement of the preintegration complex to the nucleus."
I've found similar quotes for other viruses. What we do know is that plasmids and loose DNA or RNA introduced into cell does get expressed, so it's not all that hard.
This concept is still being researched, and no definitive answer exists. How unsatisfying. Thanks people. -- Ec5618 22:35, 13 December 2005 (UTC)

longevity of herpes virus outside the body.[edit]

My question is: My understanding about the herpes virus, after reading much about it, is that the virus hides in the nucleus of the nerve cell.

Then when the body is stressed, etc or when the virus itself "decides" to shed some of its cells through the surface of the skin, how long does it live? In other words how long can it live outside the body?

I am not asking about the virus that comes out of an active lesion although that would be pertinent and important information.

However, I am more interested in "shed virus cells". How long do they live when they are on the surface of the skin or on your towel or toilet seat or whatever?

And what makes them die?

Thank you —Preceding unsigned comment added by 64.40.51.3 (talkcontribs)

The issue of whether a virus manifests "life" per se is a bit controversial; perhaps a more relevant question is the period of time the virus remains infective outside the body. Also, viruses are not composed of cells; I assume you mean "cells that are infected by virus" rather than "shed virus cells". In any case, the survival time of herpes simplex and other viruses of the herpes virus group (herpes zoster, Epstein-Barr, cytomegalovirus, and human herpesviruses 6 & 8) outside the body is quite brief. Infectivity of the viruses depends on their glycolipid envelope, which is destroyed by desiccation. The speed with which that occurs depends on the ambient environmental conditions-- heat, light, air convection, and atmospheric humidity.--
Mark Bornfeld DDS
[Brooklyn, NY 17:31, 12 December 2005 (UTC)
The article doesn't suggest that cells are released from the body, but rather that individual viral particles are expelled. These particles are susceptible to desiccation and denaturation through various means, including heat, acids, bases, detergents, alcohols, heavy metal salts, reducing agents or certain chemicals such as urea. Additionally, virusses can be destroyed by radiation or other mutating agents which can rip apart the rather unstable (RNA-)genome quite easily.
I'm not sure about exact times, but can't imagine it being more than a few minutes. -- Ec5618 18:07, 12 December 2005 (UTC)

Chemical Reaction of Sodium Carbonate Dissolving Oil Stain[edit]

I would appreciate if someone with a chemistry background could help me. I plan to do a science fair project where I will dissolve just sodium carbonate (washing soda) in hot water to remove an olive oil stain from cotton fabric. No other detergents or laundry boosters will be added and the water is soft and the sodium carbonate will not have to worry with "neutralizing" the magnesium and calcium deposits, etc. I plan to use different amounts of the sodium carbonate to see if a larger amount will dissolve the stain faster.

My dilemna is that per my research via the internet, science dictionaries and even "Wikipedia's" archives, I could not get an explanaation on the chemical process. I do not have access to university libraries and the public library is limited in their science/chemistry information. Either none was offered or advanced for my purposes. I have had some chemistry, but will not have a complete chemistry unit until next year in 10th grade.

Per my research, several scenarios should occur:

1) the sodium carbonate should create an emulsion that will list the stain from the fabric;

2) this process is the result of hydrolysis; and

3) a mild saponification could occur and convert the stain into "soap."

Your input and help would be greatly appreciated.

Thank you.

--Scott

It's really cold where I work.[edit]

Over the years I have found that the colder I get, the more frequently I need to pee. Why is that? Additionally, I am assuming that pee gets warmed up pretty well while collecting in the bladder (I suspect we've all seen it steam under the right circumstances), so why do I find that I am significantly warmer following urination? I would think that having a sac of warm liquid inside you, as well as the constant muscle tension required to hold a full bladder, would generate a bit of heat.

I don't know why it is, but I find much the same (in terms of frequency, that is). Why warmer? A possibility is that your job is sendentary, and you just sit getting cold. The exercise involved in getting up and walking to the toilet might break the ice. Notinasnaid 22:24, 12 December 2005 (UTC)
I have experienced the same sensation and wondered about it as well. I'm not sure about the increase in frequency, but I think the warming sensation must be a percieved change in temperature, not an actual change. When you pee you may be losing heat energy, but you're losing mass too. The average energy of the particles in your body, which is what we percieve as temperature, does not change (edit: unless you include the heat lost when exposing yourself in the cold. This loss could be quite large if you're a lady and need to bare your entire bum to pee. Which makes me wonder, do women get the same sensation?). When I get the sensation it is often accompanied by a shiver. Could this generate the heat? Jasongetsdown 22:42, 12 December 2005 (UTC)
Body temperature is closely regulated by the hypothalamus, which also produces antidiuretic hormone (ADH). One of the responses of the hypothalamus to cold is the inhibition of ADH secretion, with a resulting diuretic effect. --
Mark Bornfeld DDS
Brooklyn, NY 23:11, 12 December 2005 (UTC)
As mentioned by Jasongetsdown, shivering is a basic warming function. Activating muscles consumes energy and creates heat. As for ADH, a reduction of ADH will reduce water absorbtion in the kidneys. Since they are not absorbing water, it passes into the bladder and you urinate more often. Does being cold cause the hypothalamus to reduce ADH production? That appears to be what Mark Bornfeld suggested. I do not know. --Kainaw (talk) 01:50, 13 December 2005 (UTC)

Possibly weirder: why do I get hot when I play the piano? The physical activity is negligible, so could mental activity cause it? If so, why don't I get hot when answering questions here? :) DirkvdM 10:49, 13 December 2005 (UTC)

could this be some sort of Synaesthesia thing? Thryduulf 23:29, 13 December 2005 (UTC)
Interresting thought. I've never heard of heat sensation being a synaesthetic sense (and the article doesn't seem to mention it either), but if sound, taste and sight can 'synaesthetise' then why not the other senses? DirkvdM 09:12, 14 December 2005 (UTC)

siamangs (symphalangus syndactylus)[edit]

What is the subfamily of siamangs, according to scientific classification? Also, do siamangs have sexual dimorphism in body size? Do they have prehensile tails?

Try Siamang. Enochlau 22:44, 12 December 2005 (UTC)

chemical makeup[edit]

what is the chemical makeup of wheat?

  • Try Wheat--Aolanonawanabe 01:41, 13 December 2005 (UTC)
  • Wheat isn't synthetic, but alive. So its chemical make up is only a little less extensive than that of humans. It contains various enzymes, plant sap, water and a variety of other chemicals I can't name because I'm not an expert on wheat. - Mgm|(talk) 09:36, 13 December 2005 (UTC)
  • I would guess it would be mostly cellulose, but that's just a guess. --Shanedidona 23:25, 17 December 2005 (UTC)

Chimpanzee?[edit]

What is the subfamily of the chimpanzee, according to scientific classification (Linnaean Taxonomy) ?

Try Chimpanzee. Enochlau 00:27, 13 December 2005 (UTC)

December 13[edit]

Batch files and the console window[edit]

I'm running a batch file at regular intervals using Windows's Scheduled Tasks. However, each time it runs, a console window shows for a split-second. Is there a way to prevent the console window from being shown? --Borbrav 04:03, 13 December 2005 (UTC)

I haven't tried this myself, but I think this should work. Create a shortcut to the batch file and get Scheduled Tasks to run the shortcut. Now, right click on the shortcut, choose Properties, Shortcut tab. In the Run field, where it normally says "Normal Window", choose "Minimised". Enochlau 04:16, 13 December 2005 (UTC)
Something else I meant to mention: now that you're getting this working, make sure you're polite and don't hammer the server (whichever server you're querying with it) too frequently. Once a day is almost certainly fine, but if you're tempted to do it more frequently than that, consider carefully whether it's reasonable. Steve Summit (talk) 04:22, 13 December 2005 (UTC)
That's a bit of a far assumption to make. For all we know, he's archiving logs once an hour, or changing his wallpaper. Enochlau 04:31, 13 December 2005 (UTC)
Steve Summit is right, but I'm only retrieving ~8kB (Notice the "split second"), so it's reasonable (And if I weren't doing it automatically, I'd do it manually, so no difference there). As for the creating a shortcut method, it doesn't work. If in the Schedueled Tasks I select the shortcut to be run, then there is not change. If I run the link (i.e. by copying its location) nothing at all runs. --Borbrav 05:16, 13 December 2005 (UTC)
One way is to download NSIS [27] and compile this small script:
Name "ScheduledBatchRunner"
Caption "ScheduledBatchRunner"
OutFile "ScheduledBatchRunner.exe"
AutoCloseWindow true
SilentInstall silent
ShowInstDetails nevershow

Section "Foo"
  nsExec::ExecToStack 'mybatch.bat'
SectionEnd
How to use:
  1. Install NSIS.
  2. Copy this into a text file in Notepad.
  3. Change mybatch.bat to the name of your batch file.
  4. Save it as "script.nsi" (including the quotes, to ensure the proper extension is used).
  5. Find script.nsi in Explorer, right-click the file, and choose Compile. This will take a second or two.
  6. Copy the resulting .EXE into the same directory as your batch file, and change your task to run that instead. You may also add a path in step 3 and place the EXE accordingly (if you use a relative path).
If the file/path contains spaces, you must write it like so: '"my batch.bat"'.
If you need parameters, use this syntax: '"mybatch.bat" param1 param2 param3 (...)'. For parameter values that contain spaces, wrap them in "".
If you have problems, feel free to ask. --Pidgeot (t) (c) (e) 23:57, 13 December 2005 (UTC)
Works perfectly. Thanks for the help. --Borbrav 00:22, 14 December 2005 (UTC)

Hepatocellular carinoma[edit]

Pls find the below the CT scan observation..

My father has enormously large mass lesion , which involves the right lobe. It appears to involve segment VIII, segment VII , segment VI as well as segment V.The mass lession has a cephalo-caudal extent about 17cm. In the transverse plane ,the hepatic mass lesion measures about 12.0 x10.2 cm. Along the inferior aspect of the right lobe it projects exophytically from the hepatic surface.It extends up to the hepatic capsule as well.The arterial phase demonstrates evidence of mild tortuosity of right hepatic artery.Marginal dilatation is also seen of the same vessel.Lobular surface of the liver is observed,especially of the right lobe.There is evidence of thrombosis of the right portal vein.The thrombosis extends into the proximal portion of the left portal vein as well.partial thromobosis of the main portal vein is also seen.The superior mesentric vein is normal,the splenic vein is also normal.In the segment IV of the lever there is a subtle 1.0 to 1.4 cm hypoattenuated lesion,which is best appreciated in the portal venous phase and in the delayed phase.In arterial phase of the evalution ,this lesion is marginally hypoattenuated to hepatic parenchyma.The caudate lobe is normal.

Minimal dilatation of the right lobe intrahepatic biliary radicals is seen.The CBD is not dilated .The gall bladder is normal.The pancreas shows no feature of note,The spleen is not enlarged. Both adrenal glands are normal.Both kidneys are normal.There is no ascites or adenopathy.

You didn't really ask a specific question, but I'm guessing you want something like a translation into non-medical terminology. But that won't help you much. You need to ask your father's physician what the findings on the CT mean in terms of treatment recommendations. Is partial removal of liver (partial hepatectomy) an option? (The involvement of the main portal vein suggests it is not, as does the large size.) Is liver transplant? Would chemotherapy be of use? (Usually not.) Many many factors will go into this medical advice (including your father's age, state of health, other illnesses, etc.). So you'd be best off asking the physicians directly involved - and they may be hepatologists, radiologists, medical oncologists, radiation oncologists, and surgeons. They can give you medical advice, and we can't; and they have the facts they need to give you that advice, and we don't. - Nunh-huh 04:44, 13 December 2005 (UTC)

I just want to know the survial of this,yes physician has given tests to understand the stage. Incase the remedy is not available in india where we can approach.

This is still a question your physician should be able and willing to help you with - though really no one can give you a specific number. In general the survival time for a non-resectable hepatocellular carcinoma is months rather than years. - Nunh-huh 05:23, 13 December 2005 (UTC)

THC and glaucoma?[edit]

If when your vision has glaucoma it gets better with medicinal THC, theni f you don't have any glockoma vision problems, wouldn't THC actually make your vision a lot better? like 200 or three hundred times better? If it can make bad vision from near blind to be able to see, then couldn't it make good vision to VERY good vision? with reular doses? What other medicical problems require treatment with medical THC? Do you know what symptoms they have and where or what kind of doctors prescrime them? Couldn't you say if it makes good seeing intp great vision that THC is like a vitamin and could be given prescription over the counter like a normal eyesight fixing vitamin? - amon

Sadly, vision doesn't work that way. Surely you've seen people smoking pot wearing glasses??/ - Nunh-huh 04:44, 13 December 2005 (UTC)
My understanding is that glaucoma is the result of optic nerve damage caused by elevated intraocular pressure—high pressure within the eye compresses the optic nerve and surrounding tissue, causing damage. THC has been demonstrated to lower intraocular pressure (the pressure within the eye) for some patients, which may arrest or delay further vision loss.
Since normal individuals don't have high intraocular pressure to begin with, there's no additional benefit to the THC. TenOfAllTrades(talk) 07:22, 13 December 2005 (UTC)
It reduces Glaucoma, but it won't make a non-Glaucoma-ed eye get even better. A walking stick may help someone with only one-leg walk, but it won't help a two-legged person run. smurrayinchester(User), (Ho Ho Ho!) 20:49, 13 December 2005 (UTC)

What kind of human is described by the Human Genome Project?[edit]

I was going to ask whether the Human Genome Project was the genome of a single person or a group of people, but the article says it's "the combined genome of a small number of anonymous donors". What would the imaginary human described by this composite genome look like (what color skin, hair, etc.)? I assume they've sequenced both X and Y sex chromosomes, so it could be male or female.

Also, if you compared the HGP genome to that of another random person, how long would the diff be? —Keenan Pepper 06:44, 13 December 2005 (UTC)

Well rumour has it that Craig Venter is one of the anon donors.
With regard to the amount of variation, below is quoted from the HapMap project:
"Genetically speaking, humans are incredibly similar to one another. Any two unrelated genome sequences differ at only one position in a thousand, on average. The 0.1 per cent difference, which amounts to about three million base pairs of DNA in total, is what makes each of us genetically unique." [28] David D. (Talk) 07:01, 13 December 2005 (UTC)
But what do they do for these 1 in 1000 genes? Mark them with a question mark (AATCGC???CAT)? Fill them with a random letter? But to your X/Y question, if both are sequenced, the subject would turn out male. smurrayinchester(User), (Ho Ho Ho!) 20:52, 13 December 2005 (UTC)
Its not a difference of 1 in 1000 genes, it is a difference of 1 base pair every 1000 base pairs. So each gene may have a few diferences between two people. Many of these differences will have no effect on the gene function, although some will and this is why we all look different. When the difference is limitied to a 1 nucleotide difference it is known as a single nucleotide polymorphism (SNP). Other differences include small deletions or additions. Are severe example of this is the trinucleotide repeats that are responsible for many diseases. Current research is designed to find as many of the differences that are present in the human population. Such differences could be used to predict a person susceptability for certain disesases such as heart disease and cancer. The positions of known SNPs are stored in a data base not as an X in a unified human sequence. Currently there are 5.8 X 10^6 unique human SNPs (called RefSNPs and identified by an "rs" number). For more info see the following two web sites [29] [30]. David D. (Talk) 23:51, 13 December 2005 (UTC)
The idea is to identify all human genes, that everybody may not have but similarly is common enough (ie. whether it be sickle cell anemia or polydactyly) to be notable to include, ie. not just some random mutation, unless it's a random mutation that has been carved in stone and is now widespread. The differences, are therefore included. It's not the genome of one person; the concept of the "human genome" is all the possible genes in human beings. If we were to put the entire HGP into a to clone single organism, there would probably be a severe amount of conflict and that organism wouldn't be viable. For example, take an address book. The HGP is like a telephone book - every single notable phone number (where notability is judged by the publisher) - it's unlikely that it's your personal address book, and that you know everyone in that address book. However, if you were to put say, every single person's address book together for a single city, or area, then that is what the telephone book would look like. The HGP can run by this analogy - it would be unlikely - even impossible to include the HGP into a person's genome, because just as you don't know everybody in the telephone book, there is likely to be cases where you have two different versions of a trait, so having both (an absence or presence) would be impossible. If you get my drift. -- Natalinasmpf 21:29, 13 December 2005 (UTC)

wave function[edit]

can anyone explain the concept of the wave function and schrodinger's equation in simple laymen's terms? it has too many mathematical terms in wiki, and it's really confusing!

Oh dear heavens. Wave function and Schrödinger's Equation in layman's terms. Yikes. I will give it a shot, but be warned that I am simplifying in the extreme.
In quantum mechanics, subatomic particles (such as electrons or photons, for instance) can be considered to be both particles and waves at the same time (see Wave-particle duality for a good description of this). This is because we sometimes see them behaving as particles (eg in the Photoelectric effect) and sometimes as waves (eg in the Double-slit experiment).
Mathematically, physicists describe these "particles" as solutions to differential equations, typically, the abovementioned Schrödinger equation. These solutions are called wave functions, because mathematically they look like equations of waves (other, very simple examples of "wave functions" are the equations describing sound waves, for instance). So, even though these functions are describing a "particle", they have the form of a "wave", leading to the wave-particle duality concept. One of the properties of the wave function is that, if you square it, you get the probability of the particle in question being in any one place. This may sound odd, but you can't define the position and speed of a subatomic particle with 100% certainty (as expressed in the Heisenberg uncertainty principle), so the best you can do is say "there is a 20% probability that the particle is at A, a 30% probability that it is at B," and so forth.
This all sounds very abstract, I know, so I'll try an example. Take an electron around the nucleus of an atom. If you solve the Schrödinger equation for this scenario, you get a wave function describing the electron. If you square the wave function, you get the probability of where the electron could be. The result is that the electron is most likely to be found in an area a certain distance away from the nucleus (think of a shell around the nucleus, and the electron is likely to be found on that shell), with only a very small probability that it's found anywhere else. This concept of "electron shells" meshes nicely with the observations of the properties of atoms (see the Bohr model), and can explain, for instance, emission lines.
As I said, this topic is fiendishly complicated, and a thorough understanding often requires years of study at university level. However, I hope I've managed to at least give you an idea of what it's all about. I seem to recall it was Niels Bohr who said "people who claim to understand quantum physics are either lying or deluded." *grin* — QuantumEleven | (talk) 09:36, 13 December 2005 (UTC)
Are you saying the position of an electron is only defined as the probable distance to the nucleus and nothing else? In other words, is an electron sort of a pulsating sphere (getting bigger and smaller very fast) in stead of a 'linear wave' (or what should I call that?). I've long imagined it that way and your explanation seems to support it. DirkvdM 10:59, 13 December 2005 (UTC)
No, I don't think that's quite right. If you take just one electron around a nucleus of one proton (so, Hydrogen), then the electron is most likely to be found in an area that looks like a shell around the nucleus. It is possible that the electron could be elsewhere (the probability function is not 0 in other areas), but the probability is relatively small. In terms of waves, what this represents is a three-dimensional standing wave (no, the human brain cannot hope to visualise a three-dimensional standing wave). Trying to imagine what this "looks like" in real life is futile - we can't know what it looks like because it's outside of what we can picture in our minds. So the best we can do is an approximation - for instance, you can consider the electron as a particle, whose position you cannot determine exactly, but you know it's probably somewhere on this "shell" around the nucleus. Or you can "picture" (used in the loosest sense here) the electron as a three-dimensional standing wave around the nucleus. In reality, the electron is a bit of both, but we need these approximations to get around the limits of human perception. — QuantumEleven | (talk) 11:10, 13 December 2005 (UTC)
Well, isn't a three dimensional standing wave the same as a pulsating sphere? But if that were the case and it were a 'normal' wave then the probability would have to follow a sine function. But I imagine it would be more like a normal distribution. I'm sorry, my math isn't good enough to express this clearly. Let me put it this way. Does the probability drop to zero (absolute, mathematical zero) at some point (on the inside and on the outside)? And if so, does that happen fairly suddenly (sine) or does it 'peter out' (normal distribution)? DirkvdM 10:02, 14 December 2005 (UTC)
See atomic orbital and hydrogen-like atom for the details, but the lowest-energy orbital for hydrogen (1s) has a radially symmetric probability density that's fairly simple:
 P(r) = \left| \frac{r}{a_0} \exp \left(\frac{-r}{a_0} \right) \right|^2
Where r is the distance from the centre and a0 is the Bohr radius. The probability is zero at the centre of the atom (r=0) and tends to zero as r -> infinity. The peak probability is at r=a0. Higher-energy orbitals are more complex. Note that there's no concept of the electron "pulsing" as such; the (square of the) wavefunction just tells you the probability of finding the electron at any given position.--16:10, 14 December 2005 (UTC)
I can't help but notice that you're all talking about the square of the wave function(the part that relates probability), not the wave function itself--Aolanaonwaswronglyaccused 03:43, 17 December 2005 (UTC)
For further reading, I strongly suggest QED (book) by Richard Feynman. It's got no math at all, but he still doesn't dumb it down that much. —Keenan Pepper 17:00, 13 December 2005 (UTC)
The Feynman QED book is based on lectures given to the general public, and gives an appealing description of theory even beyond the wave equation. One reason for the mathematics usually seen is that it is our attempt to retain sanity while nature has other plans.
Earlier physics is most easily summarized according to Newton. If we shoot a bullet towards a wall with a vertical slit, the bullet either hits the wall or goes straight through the slit. If we spray many bullets and mark where they hit on the other side of the wall (if they get through), we get a picture of the slit. If the wall has two slits side by side, we get a picture of two slits. On the other hand, if we sink the wall into a pond and replace the gun by a bobbing ball sending out waves, what we see on the other side is waves spreading out from a single slit. More interesting still, with two slits the waves on the other side combine to give ups and downs that here reinforce and there cancel each other (interfere).
But something very strange happens if we scale down the experiment to the level of small particles like electrons, neutrons, or photons (light particles). We can perform a bullet-style experiment, marking the hits of individual particles arriving one by one. However the pattern we see, in particular the two-slit pattern, is that of a wave-style experiment! There is no way to explain this fact of nature in terms of classical bullets or waves. How could a bullet go through both slits to produce a wave-like interference pattern, and how could a wave register individual hits? This is the physical situation that the wave equation is meant to describe.
The trick that resolves the contradiction is to use probabilities. Where Newton would give the precise position and motion of the particle, so that it definitely goes from point A to point B, the wave equation is more vague. It says if the particle is at point A it is likely to end up any number of places, with the distribution of likelihood following a wave pattern.
Yes, it's a strange kind of theory. However, every time someone finds a disturbing prediction of the theory and tests it, nature replies, "I am that strange; get over it". --KSmrqT 22:11, 13 December 2005 (UTC)
I have now split my contributions to this thread in two threads, so what is the probability of me being here now? (whenever 'now' is, but that was another thread some time back.) Anyway, if I may continue my 'pulsating sphere' visualisation. Let's assume that that sphere can only pass through one of the slits when it is small (does the size of the slits matter?). That would mean that some (most) particles would hit the first wall (with the slits) and not pass through the slits (if so,are these (and their location) ever measured?). It would also mean that they hit the back wall in 'pulses' (as particles). But would they follow a stochastic distribution on the wall? If they're 'pure mathematical' spheres one would expect a 'blurred' impact zone. For them to hit a more precise spot there would have to be an underlying structure. Which there is, because they are made up of quarks. Am I making any sense? DirkvdM 10:02, 14 December 2005 (UTC)
Actually fundamental particles have no volume so they can't "pulse" :) Max 216.209.153.180 11:55, 14 December 2005 (UTC)
Forget the pulsating sphere, it's a bad mental model. There's no pulsating, there's no sphere. A neutron is made of three quarks (with gluons), but we see no evidence of internal structure for an electron or photon. For purposes of this discussion, visualize a photon or an electron as a mathematically ideal point, and don't worry about neutrons.
The probability distribution has the form of a wave, and a wave has a wavelength (distance between peaks), or equivalently, a frequency (number of peaks in an interval). We also talk about light having a wavelength (which our eyes notice as color); the two kinds of wavelength happen to agree. In fact, the theory says that wavelength is inversely proportional to momentum, which for Newton is mass times velocity. Since blue wavelengths are shorter than red, we conclude that blue light packs a greater wallop. Since the speed of light is constant, blue light is also more massive, in some sense. (Here we see Einstein's fingerprints on quantum theory.) But electrons, though slower, are much more massive than visible photons. Thus electrons have greater momentum, and consequently shorter wavelength, than light. If the wavelength of the particle is substantially greater than the width of the slit, essentially nothing gets through. (We can confirm this with ordinary water waves. But nature is exceedingly strange, and theory says that even if the wall has no slits, a particle can have a measurable probability of being on the other side when the wall is thin enough, even if it can't get through! This is called "quantum tunneling", and is routinely used in electronic devices today.) Anyway, an electron can squeeze through tighter spaces than a photon, and so an electron microscope can reveal details too small for a light microscope. In the kitchen, microwaves have a wavelength longer than visible light, so the door of a microwave oven can use a grill that stops the microwaves from escaping, but lets visible light through just fine.
Do these details make quantum theory easier to understand? Maybe not. The mathematics is actually fairly simple in structure, but the more we look at the predictions, the stranger nature seems. --KSmrqT 11:11, 16 December 2005 (UTC)
Thanks for the illumination. So the size of the slits matters, but it's the wavelength that matters. This seems to support my pulsating sphere, but that wouldn't work with the water, so I'll have to ponder on this a little more. Yet another thing to loose sleep over. Thanks a lot! :) DirkvdM 10:23, 17 December 2005 (UTC)

Empirical equation for pressure-altitude[edit]

Is there any empirical equation for pressure-altitude?How does the pressure change with altitude in the real world?

According to our article on Atmospheric pressure, a "best-fit" formula for pressure based on altitude is
\log_{10} P \approx {5-{h \over 15500}}
where P is in Pascals and h in meters. It's a relatively good fit, but the results produced won't be as good during "extreme" weather conditions (eg a hurricane). Also, don't forget that ground pressure will vary with the weather and time of day, so that will have an effect too.
The only way you can find out the pressure change with altitude "in the real world" would be to take a plane and measure it - the mechanics governing pressure variations are complicated and calculating them is virtually impossible. However, we can (and do) simulate them as part of weather forecasting calculations - however, this is obviously not 100% accurate, and needs copious quantities of computer power. — QuantumEleven | (talk) 09:46, 13 December 2005 (UTC)
  • The article also says: As a rule of thumb, the pressure decreases by about 1% for every 80 metres increase in altitude. An alternative rule of thumb, density decreases by half every 20,000 feet below the tropopause, and every 15,000 feet above the tropopause to the stratopause.

Mobile Phones Spyware[edit]

Is there a spyware that you can install on mobile phones?

Not yet. There's only ever been one mobile phone virus, and you'd have to be quasi-retarded to even let that onto your phone. Proto t c 11:17, 13 December 2005 (UTC)
Supposedly the phone company knows where you are, pretty close geographically, with or without GPS when your mobile phone is powered up, so that the rest of the wireless phone network can talk to yours. Supposedly law enforcement can tie into that to get a map like data base of where all the phone subcribers are.
Have you seen movies of Air Traffic Control where they have like radar screens having symbols of different aircraft located where? Well think of that concept except instead of planes on the map, it is people. Of course this Big Brother technology not to the point yet where they know WHAT you are doing, but your ISP communications could get recorded. AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 21:25, 14 December 2005 (UTC)

Page Refreshing[edit]

I use Internet Explorer,Opera Browser as well as Mozilla Firefox.The problem I have is that after opening a webpage once,the updated page for the next day doesn't open. eg I opened the page www.arsenal.com about 3 months ago.Now,whenever I open arsenal.com again,the page from 3 months ago opens.Why does this happen and how can I undo this?

I've already deleted all of my history,temporary internet files and cookies.It did't work.My PC does not have ANY sort of Spyware or Adware(I use 6 different softwares).

Please,help needed.Thanx in advance.

PS: I use a proxy server.Does that matter?

The proxy server could be your problem - it could be caching pages and not fetching refreshed pages correctly. Try doing a forced refresh (CTRL+F5), this forces your browser to get the latest version of the page.
Have you tried a direct connection, bypassing the proxy? If that solves the problem, then you've found the cause (the proxy server). If it doesn't, it could be a problem with your browser, although you must have customised the settings quite heavily for this to occur. In IE, you can check Tools -> Options -> Temporary Internet Files -> Settings, and set this to "every visit to the page" or (better) "automatic". Although if you say that it's a problem with every browser you use, to me that's screaming "proxy server". — QuantumEleven | (talk) 11:29, 13 December 2005 (UTC)

Thanks for replying,QuantumEleven.Ctrl+F5 didn't work.Disabling the proxy server did.[:)]Thnx.But now (as expected) the speed of my net has taken a nose-dive.Is there any other way?

Well, that depends - do you run the proxy server? If so, then you can take a look at its configuration to see where it's going wrong, because the behaviour you're describing is not the way a proxy server should operate! A proxy server should store copies of web pages so you can access them quickly, but it should also be checking to see if its copies are the most up-to-date - this is something it doesn't appear to be doing. Is there a good reason why you're running a proxy server? What kind of connection do you have?
(obviously, if you're not the one administering the proxy server, then this discussion is moot - you'll need to talk to the person running your proxy server and get them to sort it out! :)). — QuantumEleven | (talk) 10:58, 14 December 2005 (UTC)


"(obviously, if you're not the one administering the proxy server, then this discussion is moot - you'll need to talk to the person running your proxy server and get them to sort it out! :))."

You hit the nail smack on the head! thnx dude...!

AS/400[edit]

how do i get free notes on AS/400 how do i get free e-materials on AS/400 —Preceding unsigned comment added by 202.131.103.174 (talkcontribs)

Moved from Wikipedia_talk:Community Portal. x42bn6 Talk 13:01, 13 December 2005 (UTC)
  • My career is involved with this. You might want to post questions separately on my User talk:AlMac talk page.
  • Assuming you are at a place with an AS/400 where you have been granted security access to sign on to the system.
    • F1 is the universal help key. Any place you have a question, or need to get documentation, just put the cursor on what you want to know more about, and press F1. A lot of screens are cursor sensitive. Depending on where the cursor is on the screen, different places plus F1 will give you access to different facets of the documentation.
    • Note that on the IBM keyboard the function keys go from F1 to F24 while on many PC Keyboards they only go from F1 to F12. Often you can get at F13-F24 on a PC keyboard by doing upper shift corresponding F1-F12. There are numerous other cheats out there to make this easy to remember which is which. It can be useful to check any manual on any IBM "dumb" terminal, since the keystroke combinations are pretty standard.
      • Example, suppose you are at a PC keyboard connected to an AS/400 ... upper shift ESCAPE key then ENTER is often the same as doing a SYSTEM REQUEST on an IBM keyboard, which gives you access to a ton of system stuff. I think one of the coolest keys is the HEX key, which gives rapid access to HEXADECIMAL data. Basically, your starting point is to get your hands on a manual for ANY IBM dumb terminal, because the stuff in there about basic keyboarding applies across the board to just about any interface available to you.
  • All the IBM manuals are on_line freely accessible, if you know how to navigate them.
    • Client Access for example is the most common way people connect (via a PC) to AS/400 nowadays ... we can also access via Web pages, "dumb terminals", FTP, TELNET, lots of ways. Basically a useful skill is learning how to navigate IBM documentation on-line.
      • Spoiler warning ... IBM is constantly trying to improve their on-line documentation, but they are not real good at this, so invariably any skills you aquire learning the old way of accessing are not much help to you the new way.
  • There are hundreds of thousands of AS/400 users around the world in various discussion groups. My favorites are at midrange dot com but there are many others, mostly hosted by magazines about AS/400 such as IT Jungle.
    • Just about every AS/400 magazine web site is rich in resources. Forums, Articles, Archives, White Papers, Manuals, you name it ... but in most of them you have to register, and in some cases join for a nominal fee.
    • The AS/400 user community also has their own Wiki ... it is relatively new, so it is not as rich in articles as this place.
    • There are also numerous AS/400 user groups such as Ignite/400.

AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 21:30, 14 December 2005 (UTC)

Networks[edit]

what is the difference between a hug & a Switch?

Before someone gives you a smart answer, I think you meant a 'hub'. Proto t c 13:27, 13 December 2005 (UTC)

But here's the belated smart answer: a hug gives you a warm, cozy feeling; a switch gives you red welts. 14:11, 17 December 2005 (UTC)
See ethernet hub and ethernet switch. --Robert Merkel 13:32, 13 December 2005 (UTC)
At last, a chance to provide my favorite answer: a hub has RJ45 jacks on the back and port activity lights on the front.
A switch has jacks and lights both on the front. Steve Summit (talk) 18:13, 13 December 2005 (UTC)
I belive the chief difference is that a hub transmits all data it receives to all of its output ethernet wires, while a switch examines the packets it receives and tries to transmit them only to the output where it is destined. So a hub is simpler, but a switch conserves bandwidth. In case of a hub, the machines connected to it (either computers or switches) will examine the packet and throw it away if it's not destined for them. I'm not sure in all this though. – B jonas 20:10, 15 December 2005 (UTC)
That used to be the distinction, until dual-speed hubs came along. Those don't necessarily send all data to all outputs, because otherwise high-speed data destined for a high-speed recipient would be unnecessariloy bogged down by the need to throttle it for low-speed non-recipients. I used to think that "dual speed hubs" were therefore really switches, although the section on "Dual speed hubs" in the Hub article suggests I was wrong. Steve Summit (talk) 14:05, 17 December 2005 (UTC)

why do we need a pair of coils in a cable?[edit]

why do we need a pair of coils in a cable? Can't one be enough?

What kind of cable? Notinasnaid 15:49, 13 December 2005 (UTC)
If this is in reference to signal cables, see balanced line, differential signalling, and common-mode interference (which is what the first two are good at rejecting.) -- AJR | Talk 01:48, 14 December 2005 (UTC)

Direction of current flow[edit]

(no question)

Engineers usually consider current to flow from high to low voltage; physicists interpret current flow from low to high. — Lomn | Talk / RfC 17:17, 13 December 2005 (UTC)
River currents flow from high to low.
Surface ocean currents are generally wind driven and develop their typical clockwise spirals in the northern hemisphere and counter-clockwise rotation in the southern hemisphere. Deep ocean currents are driven by density and temperature gradients. Thryduulf 23:19, 13 December 2005 (UTC)
The direction of current, in terms of engineering is defined as in the opposite direction to the flow of electrons. Therefore the electrons in a circuit flow from low to high voltage, which means the current flows from high to low. - Akamad 08:58, 14 December 2005 (UTC)
  • It would help if you told us in what context you are asking this question. - Mgm|(talk) 09:20, 14 December 2005 (UTC)

How many websites will Microsoft ISA hold before it chokes[edit]

I have a lot of websites to block using Microsoft ISA. How many records can I put in a rule-set?

AUTOMATIC TRANSMISSION[edit]

PLEASE TELL ME, HOW TO MAKE AN AUTOMATIC TRANSMISSION FOR A CAR, AND WHAT MATERIAL FOR MAKE IT?

With great difficulty. Building a one-off, custom automatic transmission would be an enormously complex task; you'd have to build an entire geartrain, a torque converter chamber, probably software to control it...if this is for a custom car project, try to find an existing one with the right size and characteristics and figure out how to adapt it to your purpose. If this is some kind of engineering exercise for an individual, building a toy torque converter *might* be on the ragged edge of feasibility, though getting it to work right will be very challenging (as I understand it, it would depend very much on the viscosity of the fluid you used). Access to some computational fluid dynamics software, and learning how to use it, might help a lot. Finally, if you want to go into the automatic transmission manufacturing business, hire a bunch of engineers, preferably ones who've worked in the transmission divisons at companies like ZF Friedrichshafen AG or Borg-Warner. Start by taking apart a bunch of existing designs, and prepare to spend a lot of time dealing with patent lawyers if you want to sell the results in developed countries... anyway, see automatic transmission for some basic information on how they work. They're mostly built of various grades of steel. --Robert Merkel 22:17, 13 December 2005 (UTC)
To give you an idea of the complexity, this company is an example of one making custom torque converters for racing purposes. --Robert Merkel 10:34, 14 December 2005 (UTC)

Glaucoma vis-a-vis Cateracts[edit]

Are there any problems or side effects or complications if a person with Glaucoma and requires Cataract surgery?

  • I can't be perfectly sure, but I doubt that replacement of someone's lense is going to affect pressure on their optic nerve. If you are worried about such side effects, talk to an opthamologist or optometrist. - Mgm|(talk) 09:25, 14 December 2005 (UTC)

Please help me- SILICONE[edit]

I have a film of silicone on my hands, how do I remove it? You are my last hope... maybe someone knows? Google results with nothing in particular...

Silicone sealant is somewhat difficult to remove. This google answer might be of assistance. Rubbing alcohol and, if necessary, a scrubbing brush, would seem to be the more conservative options. --Robert Merkel 22:05, 13 December 2005 (UTC)
I expect it'll come off eventually by itself as your epidermis renews itself. Scrubbing with a brush and some soap should help the process along. I don't know if rubbing alcohol will help, but I don't see what harm it could do (in moderate amounts) either. —Ilmari Karonen (talk) 22:15, 14 December 2005 (UTC)
Rubbing alcohol won't work any better than water. The silicone film will take between hours and days to come off, papers towels are the best bet if it is too irritating. Physchim62 (talk) 17:54, 15 December 2005 (UTC)

Pointlike particles[edit]

If all particles are pointlike and they have no real volume, then wouldn't all particles with mass have infinite density and be black holes? Please help 216.209.153.115 22:34, 13 December 2005 (UTC)Max

Your problem is you're misunderstanding the nature of division. The density of something is mass divided by volume. The volume of a point particle is 0. mass/0 is undefined (indeed, anything/0 is undefined). It is not infinite. So the density of a point is undefined - they don't have a density because they don't have a volume. Check out division by zero. -- Finlay McWalter | Talk 23:04, 13 December 2005 (UTC)
That's wrong though. A Black Hole can (in theory) be said to have infinite density. See the article. Just because it's a division by zero doesn't necessarily mean it's "undefined". The density is mass/volume, and the limit as volume goes to zero is that the density goes to infinity. There are plenty of singularities in physics, and they aren't usually treated as something simply 'undefined'. Taking the limit certainly makes most sense. --BluePlatypus 00:10, 14 December 2005 (UTC)
(edit conflict) You are misunderstanding what a black hole is; a black hole is not defined by an object having "infinite" density. A black hole, instead, is an object whose mass is so great that the gravitational field it produces is strong enough to capture even light. Particles, being very small, aren't able to create massive gravitational fields on their own, and as such aren't black holes. Enochlau 23:07, 13 December 2005 (UTC)
I guess you could think of elementary particles as being tiny black holes. Many properties of a black hole are also true of, say, an electron (for example the no hair theorem — electrons have no hair either). But I don't know what good that would do you... —Keenan Pepper 23:22, 13 December 2005 (UTC)
Just for kicks, what would the Schwarzschild radius of an electron be? How does it compare with, say, the Planck length? —Keenan Pepper 23:24, 13 December 2005 (UTC)
(Answering my own question) The Schwarzschild radius of the electron is 1.35 × 10−57 meters, much smaller than the Planck length. —Keenan Pepper 23:35, 13 December 2005 (UTC)
What mass would be nessecary for a Schwarzschild radius of one Plank Length? Max again 216.209.153.14 00:53, 14 December 2005 (UTC)
That's the Planck mass; the black hole would be roughly equivalent to a gravitationally collapsed flea. By the way, there has occasionally been speculation on whether electrons could be black holes (see Black hole electron); there are various difficulties with the idea, such as Hawking radiation. ᓛᖁ♀ 01:35, 14 December 2005 (UTC)
Wow, I thought I was just making that up, but it turns out we have an article on it! I love Wikipedia! —Keenan Pepper 05:14, 14 December 2005 (UTC)
I'm wondering whether Hawking radiation would really matter. After all, exactly what particles would a charged black hole with the mass of an electron radiate? To vanish, it would need to radiate something charged, and it can't radiate away more mass than it has. (Of course, this is all idle speculation. Without a proper theory of quantum gravity, we can't very well be expected to reason rigorously about the properties of tiny black holes.) —Ilmari Karonen (talk) 14:35, 15 December 2005 (UTC)

December 14[edit]

Maxwell's Demon[edit]

The concept of Maxwell's demon was proven to not be able to lower entropy because it creates more entropy in the process (see link). What if instead of a demon there was just a small slit? If a high-energy particle happened to slip through, wouldn't that violate entropy? Thanks, Max 216.209.153.14 00:59, 14 December 2005 (UTC)

Sure, a high-energy particle can slip through. But so can a low energy one. In order for a Maxwell's Demon-type thing to work, there has to be some kind of sorting going on - but I don't see what characteristic a slit has which sorts fast particles from slow ones; it's not as if fast particles are thinner than slow ones. -- Finlay McWalter | Talk 01:14, 14 December 2005 (UTC)

If a very high or low energy particle did happen to slip through first, entropy would be violated, at least temporarily. Additionally, according to quantum physics, higher energy particles have a more concentrated probability field - so they are thinner. Max 216.209.153.14 01:27, 14 December 2005 (UTC)

The relevant law is the second law of thermodynamics. It is expressed as a tendency, not an absolute law, so the behaviour of the single particle mentioned by Max is not a violation. --Heron 17:33, 14 December 2005 (UTC)
  • Also consider: Your particle has gone through the slit. Now there's a greater concentration of high-energy particles on one side, and so there's a greater probability that one of them will go back through the slit to the other side. Statistically, it will even out. --Bob Mellish 17:49, 14 December 2005 (UTC)

What if the change in this particle's state prevented further contact between the two objects? Max 216.209.153.78 22:52, 14 December 2005 (UTC)

  • Well, how is the particle's state changing and what mechanism prevents further contact? --Bob Mellish 16:52, 15 December 2005 (UTC)

The higher energy concentration on one side could knock a door closed (There has to be a better example but I can't think of one). Max 216.209.153.17 16:39, 16 December 2005 (UTC)

Lemons[edit]

Lemon.jpg

When a lemon is cut in half you can see that it is actually made up of several smaller sections. For example this lemon is made of nine sections. Is this the same for all normal lemons? Does this relate also to the number of petals the lemon tree's flowers have? - Theshibboleth 02:44, 14 December 2005 (UTC)

  • I suspect that, like with oranges, the number of sections can differ be specimen. According to our article: "In botany, a fruit is the ripened ovary--together with seeds--of a flowering plant." The number of petals on the flower appear not be included in the formation of the fruit and are thus unlikely to affect the number of sections in it. - Mgm|(talk) 09:33, 14 December 2005 (UTC)
  • The number of petals on most plants is not variable. Flower structures are often used to differentiate between speicies, thus more petals would denote a different species (although this is not always true, otherwise "she loves me/she loves me not" would be rather predictable). If you look around for pictures of orange blossoms [31] you'll note that they all have five petals.
In fact, [László Mérő] mentions this in his book ""Mindenki másképp egyforma"" (the English translation apparently has the title ""Moral Calculations""). In chapter 11, he states that the ""loves me, loves me not"" game is indeed sort of deterministic for this exact reason (most flowers have flowers have an odd number of petals), but it's not entirely deterministic as often one or more petals have fallen off the flower. – B jonas 19:59, 15 December 2005 (UTC)
  • The number of carpels determines the number of sections. The carpel number is not necessarily related to the petal number. David D. (Talk) 17:44, 14 December 2005 (UTC)

MAPI Service[edit]

Ever since I installed the Norton SystemWorks 2006, Norton Firewall 2006, Norton Antispam 2005, I have been getting the following window every time I turn on my computer.

Managed MAPI Service Catastrophic Failure
Unknown error

The only button on the small pop-up window is OK. How do I stop the window from popping up? My operating System is Windows XP Media Center Edition 2005.

--66.81.19.12 03:18, 14 December 2005 (UTC)

See Symantec's solution for that problem here. -- Daverocks 09:25, 14 December 2005 (UTC)
  • Symantec's solution is downloading and installing updates for Norton Antispam 2005, but my update gets aborted whenever I try to get the update -- this only happens for Norton Antispam. I get the following error message.

Windows XP 5.1.2600 Service Pack 2

AntiSpam Feature 2005.1.02

LiveUpdate was not able to complete this update.

Please contact Technical Support and provide all information displayed on this screen. For contact information, go to Help->Technical Support from your Symantec product.

The files below could not be updated by LiveUpdate:


File: C:\PROGRA~1\COMMON~1\SYMANT~1\Options\UIHelper.dl^ 100448 Bytes 9/23/2005 17:38:44 v2006.2.0.153.

Have you tried uninstalling and reinstalling Norton Antispam? That might solve your problem (you may need to uninstall and reinstall the rest of the suite as well, I don't know how tightly integrated it is). — QuantumEleven | (talk) 08:32, 16 December 2005 (UTC)

Thank you.

Slashdot question[edit]

Screenshot linked to save space

What does the text "n more" mean under some of the section links in the slashdot sidebar? --pile0nadestalk | contribs 04:41, 14 December 2005 (UTC)

I believe in Slashdot terms it means there are n more articles in that subject that where not shown on the front page. --Martyman-(talk) 04:42, 14 December 2005 (UTC)

Thanks --pile0nadestalk | contribs 04:51, 14 December 2005 (UTC)

Foot vaccination in India[edit]

John a Wikipedia question sent the following question to the Wikimedia Help desk.

"My friend a Lady is an orphan born India 1954. She is vaccinated on the sole of her right foot? is this normal in India?"

If you can help answer the question it would be greatly appreciated. Capitalistroadster 07:15, 14 December 2005 (UTC)

  • I'm not an expert in the field of vaccination, but I believe that it's a common way of vaccinating infants (in India as well as the Western world). It may be because the veins in her arm were hard to see (so they used her foot instead), or perhaps, she already had several vaccinations in her arm, so they used her foot to give the arm time to heal. - Mgm|(talk) 09:37, 14 December 2005 (UTC)
  • I have never heard of vaccinating on the sole. This of course does not mean it is not "common" in Asia, but I doubt it is "common in the Western world." The most common site in the US in the years it was being done was the upper arm. Smallpox vaccination involved scratching the skin (which is why it left a visible scar), not finding a vein or giving an injection, so the vein explanation or multiple injection explantion is irrelevant. alteripse 18:13, 14 December 2005 (UTC)
  • When I said infants I'm referring to kids no older than 1 year. I've heard of such a practice and I'm not claiming it's common practice for anyone over that age. - Mgm|(talk) 20:37, 14 December 2005 (UTC)
    • I think everyone has stopped doing smallpox now. Just for my own education, where and when was foot vaccination in infants common? alteripse 21:48, 14 December 2005 (UTC)
      • My research adviser from undergrad was vaccinated on the sole of her foot so that the scar wouldn't show if she wore something sleeveless. She was still kind of bitter that her doctor was that sexist; he vaccinated boys on the arm, where it hurts much, much less. I was never quite impolite enough to ask her age directly, but I think this practice has been discontinued, and I know it wasn't widespread; my mom's vaccination scar is on her arm. --Joel 13:30, 21 December 2005 (UTC)

what is the bandwidth required for on-demand computing[edit]

what is the bandwidth required for on-demand computing where processer is far away and only input and output devices are here?

It depends on the application(s) in question. You need enough bandwidth to make the use of a distant (presumably more advanced) processor preferable to a local one. — Lomn | Talk / RfC 14:19, 14 December 2005 (UTC)

Origin of the word Cancer[edit]

Where does the word cancer come from? I heard it is originated from hippocrates, who investigated breast cancer and the spiny venes reminded him of a crustacean. But how does that explain the word cancer? Thanks, Meike

This seems to be about right; according to Paul of Aegina, Hippocrates made the connection because "the veins stretched on all sides as the animal the crab has its feet". According to Webster's Revised Unabridged Dictionary, "It was so called, perhaps, from the great veins which surround it, compared by the ancients to the claws of a crab." The tumor meaning has been attached to cancer for a very long time. [32] ᓛᖁ♀ 13:39, 14 December 2005 (UTC)
To answer you question "How does that explain the word cancer" more specifically, the astrological sign "cancer" is represented by the crab. Jasongetsdown 15:51, 14 December 2005 (UTC)
Never mind astrology. Cancer is the Latin word for crab. --Heron 17:25, 14 December 2005 (UTC)
In some languages (Danish, Norwegian and 19th century Swedish come to mind as I'm scandinavian) - the name actually is the native name of a similar (but not identical, compare crab) animal, the crayfish. (it's "kræft" in da, "kreft" in nb, "kräfta" in 19th century Swedish but "cancer" in modern Swedish). Unfortunately, I don't know the origins. It might a mistranslation or have its own origin. TERdON 23:57, 14 December 2005 (UTC)
These are probably all derived from a Germanic root meaning "to claw" which may also have produced crayfish by folk etymology. [33] ᓛᖁ♀ 00:20, 15 December 2005 (UTC)

Blood types[edit]

What is the difference between someone with a positive blood type and a negative, for example A- or A+ thanks,--anon

See our article on blood type. TenOfAllTrades(talk) 14:52, 14 December 2005 (UTC)

Yeah, it didn't explain it.--anon

  • The section Blood type#Rhesus system (CDE) explains the plus-minus. If you're asking what the difference is between people of different blood types -- none, other than their ability to safely donate or receive blood of particular types. --jpgordon∇∆∇∆ 18:02, 14 December 2005 (UTC)
  • Plus/minus refers to the presence of the Rh factor. Rh is an antigen which may or may not be on the surface of red blood cells. If you have it then your blood type is (+), if you don't then it is (-). Why we have a gene for this antigen? We do not really know, it may be some evolutionary remnant. Nrets 19:34, 14 December 2005 (UTC)

Lymph nodes[edit]

How many lymph nodes does a human have on average?

Humans have approximately 500-600 lymph nodes. --David Iberri (talk) 15:30, 14 December 2005 (UTC)
Thanks. Added it to the article. --WS 22:09, 14 December 2005 (UTC)

DBMS[edit]

WHAT DOES A DATA BASE MANAGEMENT SYSTEM ALLOW US AS USERS TO DO?

Nothing. It organises data. But if you add in applications that use the DBMS, then you as end users gain the ability to work with that data. Most business processes these days involve dealing with large amounts of data, from contact lists to human genomes, and the DBMS is charged with storing, organising, and providing efficient access to that data. Does that hope with your homework? Notinasnaid 16:06, 14 December 2005 (UTC)
It also depends on the system. Many computer infrastructure providers use similar terminology for systems that have extremely different capabilities. AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 22:06, 14 December 2005 (UTC)

DB Systems of NASA[edit]

The latest issue of e-week has a truely fascinating article on how NASA presents different kinds of data for people to utilize. NASA has defined 12 different domains in which Earth Science Satelites has beneficial applications, organizing that data into different collections optimized to the needs of those applications. I would hope that there are Wiki articles some place on some of these concepts.

  • ECHO = Earth Observing System Clearninghouse
  • ESDIS = Earth Science Data and Information Service Project
  • SOA = Service Oriented Architecture
  • UDDI = Universal Description, Descovery, Integration

User:AlMac|(talk) 20:55, 15 December 2005 (UTC)

PC to mobile and mobile to PC[edit]

Many services offer free SMS from PC (say messenger) to mobile. Is there mobile to PC service apart from the service which offers users ability to reply to PC-to-mobile messages?

Yes, my GSM provider offers such a service [34]. All you have to do is send an SMS to a special number, and they'll send an e-mail, so this is available from any old mobile phone. The recipient address, the subject of the message, and its body are all specified in the same message. This, of course, limits you to short e-mails only. It costs the same as a normal SMS I think, but I'm not sure. – B jonas 19:42, 15 December 2005 (UTC)

Fainting[edit]

TV and movies often show people faining when they see something shocking or disturbing. Does this happen in real life? Fainting doesn't say. --Quasipalm 18:45, 14 December 2005 (UTC)

Yes, one may faint in response to strong emotions or stress. It's called vasovagal syncope. Let me know if you have any questions. — Knowledge Seeker 19:31, 14 December 2005 (UTC)

HTML Forms (Wikipedia-related)[edit]

The "section edit" form on Wikipedia contains a one-line "subject/headline" field and a multiline text box (see http://en.wikipedia.org/w/index.php?title=Wikipedia:Sandbox&action=edit&section=new). Currently, if you hit "Enter" in the subject/headline field, most browsers will treat this as a "submit" request, apparently because this is the only one-line field on the form (Bugzilla:4273). Is there any way to change the table markup so that the form will work the same way, but that browsers won't treat Enter as a "submit" request? From what I can tell, the Summary field is an input field, while the text box is a textarea, but I'm not very good with html forms. -- Creidieki 20:08, 14 December 2005 (UTC)

There's a javascript trick for this. Most browsers seem to treat hitting Enter on a form as a click on the first submit button on that form. Therefore inserting a transparent 1×1 pixel image button at the top of the form and giving it an onclick handler that returns false will prevent hitting Enter from submitting the form. It's a crude hack, I know, but it seems pretty reliable in practice. —Ilmari Karonen (talk) 22:05, 14 December 2005 (UTC)

help me please (urgent)[edit]

I must be knowing any effect or dangers that would be coming if someone (not being me!) were to be ingesting 5 heroin filled game rabbits. please be helping. Should I be going to the hospitle after doing that? This is urgent!

5 heroin filled game rabbits? What the heck is a heroin filled game rabbit?--Aolanonawanabe 21:50, 14 December 2005 (UTC)
I still want to know what a heroin filled game rabit is--Aolanaonwaswronglyaccused 03:37, 17 December 2005 (UTC)
Yes, probably. Heroin overdose can be extremely dangerous. ᓛᖁ♀ 21:45, 14 December 2005 (UTC)
Are we to assume the rabbits have been cooked? And did the rabbits ingest the heroine or were they injected with it? If injection, before or after their death?


my suggestion is
immediately without delay to get the victim to a hospital to have their stomache pumped out.
be prepared to give a statement to the police in which the cross examination may last XXX hours.

AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 22:09, 14 December 2005 (UTC)

  • Why would you need to be able to give a statement to the police? Wouldn't the doctors reporting that be a violation of medical privacy? -- Creidieki 04:21, 16 December 2005 (UTC)

Depending on nation state etc. there are often laws requiring medical personnel to inform the police when a person's medical condition implies that some reportable crime may have occurred, such as

  • gunshot
  • illegal drugs consumed
  • rape
  • child abuse

User:AlMac|(talk) 17:43, 16 December 2005 (UTC)

  • Interesting stuff about medical privacy. Heroin filled game rabbits are still kind of confusing me however.
Apart from the obvious oddities already mentioned - ingesting five rabbits? Were they baby rabbits? DirkvdM 10:29, 17 December 2005 (UTC)

Execute order 66?[edit]

As you all know in th uber popular movie return of the sith, they made a clon army that without knowing about it, was programmed to assasinate the good guys in the movie, even though they were trained from birth to be clones? But could or how would this wor in real life? Could it have been done and we might not ven know about it? until late? opinions? science? facts?- anon

  • Current state of art ... the clone arrives as a fetus, with normal speed development same as an ordinary child.
  • There was another thread somewhere now in the archives, about risks of science, when commercial interests are more interested in short term profits than safety.
    • Mad Cow disease is man made accident, that originated with Mad Sheep Scrapie got passed to cattle, then thanks to careless experiments with Deer, it is now in the wild, at least in North America, with most wild animals susceptible, because the food chain that eats the Deer, also gets this. Pigs and other livestock also got it. So this is not because of evil intent, but short cuts thanks to greed.

AlMac|[[User talk:AlMac|<sup>(talk)</sup>]] 22:13, 14 December 2005 (UTC)

The clone troopers in Revenge of the Sith weren't actually genetically programmed to execute Order 66, they were trained to obey the orders of the Supreme Chancellor above all others. --Canley 23:20, 14 December 2005 (UTC)

Toe Jam?[edit]

What is Toe Jam and how is it formed?

Toe Jam is a sweet preserve made from toes. First, debone the toes, removing the nails if necessary. Next, chop the toes into small cubes about 5mm x 5mm x 5mm. Put in large pan. Add equal weight of sugar, and enough water to fully dissolve the sugar. Boil until thick. Alternately, a toe jam is when you jam your toe against a wall, thus compressing the bones. --YixilTesiphon Say helloBe shallow 22:53, 14 December 2005 (UTC)

According to wiktionary:toe jam, it is "the accumulated matter in between the digits of the foot." Like navel lint (I can't believe that's an article), it's mainly composed of stray clothing fibers and dead skin cells. —Charles P. (Mirv) 23:00, 14 December 2005 (UTC)

html/java[edit]

Well, i am doing a website and i want to create a login/sign up but i don't know how to do that. Can you help me? -Mumai

If all you want is to make some part of your website accessible with a password, you have to configure the webserver so. Read the Apache manual for example: [35], although I guess there may be more comprehensive descriptions too. -- (sorry, it seems I forgot to sign this) B jonas 19:25, 15 December 2005 (UTC)
There are host sites you can buy into, that come almost default that way, such as Weblogger.
Setup the site as restricted, then there is a place you go to define new users and invite them to join, or send them password (like in e-mail which is not exactly secure).
This kind of system is for people who want to be able to use the power of the Internet, without having to learn the programming that is needed to make things work.

User:AlMac|(talk) 21:02, 15 December 2005 (UTC)

December 15[edit]

Hydroelectricity Power[edit]

Where geographically is hydroelectricity used?

You might want to read Hydroelectricity. -- Rick Block (talk) 01:05, 15 December 2005 (UTC)

Nature peer review[edit]

How much can be extrapolated from the results of Nature's review of Encyclopedia Britannica and Wikipedia? How should the margin of error for the average number of mistakes per article be calculated? ᓛᖁ♀ 01:21, 15 December 2005 (UTC)

They don't mention the depth of coverage for each article so its hard to extrapolate. I assume they picked articles that were similar. If so, looking through that list of errors compared to Britannica, i'd say that wikipedia is in very good shape. David D. (Talk) 01:26, 15 December 2005 (UTC)
Unfortunately the standard deviation for the number of mistakes per article is slightly higher for Wikipedia (3.47) than for Britannica (2.43), suggesting our quality may be more variable. ᓛᖁ♀ 03:04, 15 December 2005 (UTC)
Well no surprise there. Some of the wikipedia science articles are terrible. But they are all a work in progress and will improve eventually. David D. (Talk) 04:12, 15 December 2005 (UTC)

Is there currently a drive or WikiProject to improve the quality of the articles in question, or for that matter, does anyone maintain a list of WP articles mentioned in the media as needing improvement? I would imagine a list of those articles would be good to have, as experts will be attracted to them, and they're also likely vandalism targets, so they should be watched and improved. This is just a suggestion, but if it doesn't exist I'd like to start something like that.

Did I deviate too far from science to be on the reference desk? I hope not. --ParkerHiggins 03:35, 15 December 2005 (UTC)

maybe Wikipedia:External peer review would be helpful? Broken S 03:38, 15 December 2005 (UTC)
I made a little list that at least temporarily is here, but the improvement drive is really at Wikipedia:External peer review. The task is complicated by the fact that Nature did not specify the errors of fact, omission, or misstatement.- Nunh-huh 03:40, 15 December 2005 (UTC)
A number of people posted on the village pump that they got responses back from nature saying they are working on publishing the list of errors on their blog, so stay tuned. - Taxman Talk 21:40, 16 December 2005 (UTC)
Nature has a blog? Do you have a link? David D. (Talk) 21:45, 16 December 2005 (UTC)
Yes, amazingly enough they do. Here's the link to the issue at hand. You may also be interested in the coverage at Wikipedia:External peer review. - Taxman Talk 17:59, 19 December 2005 (UTC)
Why didn't the Nature reviewers correct the errors they found, when they found them??? MPF 23:44, 19 December 2005 (UTC)
This is exactly what i was looking for. Thanks a bunch, guys. --ParkerHiggins 03:46, 15 December 2005 (UTC)
Alternatively, at least one of the science WikiProjects is looking closely at the results, and trying to make sure that we do better next time! Physchim62 (talk) 18:00, 15 December 2005 (UTC)

How long can the human body go without sleep?[edit]

Just wondering--Aolanonawanabe 03:48, 15 December 2005 (UTC)

sleep deprivation gives an answer. - Nunh-huh 03:50, 15 December 2005 (UTC)
Ah thanks, I knew finals were torture, never knew it was that literal (: --Aolanaonwaswronglyaccused 03:36, 17 December 2005 (UTC)

proper sound loudness unit for humans[edit]

The decibel is a commonly used unit of sound loudness. However, according to the article, a decibel is a dimensionless unit. There are several variations on the decibel listed in the article, but I'm unable to figure out which one is correct. Which decibel variant is the correct one to use when talking about the subjective loudness of a sound to humans? Or is merely decibel sufficient? --Cybercobra 04:20, 15 December 2005 (UTC)

A bel is just a factor of 10. A decibel is one tenth of that, so it's a factor of 101/10. The actual unit for measuring sound intensity is the watt per square meter, but it's much more commonly stated as a number of decibels in relation to 10−12 W/m2. For example, 30 dB is 1000 times that intensity, so 10−9 W/m2.
However, sound intensity is not the same as subjective loudness. No matter how loud a sound is at 50 kHz, you won't be able to hear it (but your dog might). Apparently the unit for subjective loudness is the phon. —Keenan Pepper 05:49, 15 December 2005 (UTC)
Thanks. I've improved the Category Human-based units of measure accordingly. --Cybercobra 03:08, 16 December 2005 (UTC)
You're correct about a decibel being dimensionless, so it really just describes ratios. When used in the audio world, it's often used with a specific reference. While people may say "that sound was 85 decibels", they really mean something that should be written as something like 85 dB(SPL), which compares it to a reference level of 20 micropascals. Decibels have many other standard references, such as dBm, dBv, etc... kmccoy (talk) 00:50, 22 December 2005 (UTC)

Acetabulum - are unit and body part related?[edit]

Is the unit Acetabulum related to the same-named part of the human body (e.g. does the unit = the volume of bodypart)? Or is it merely coincidence? --Cybercobra 04:25, 15 December 2005 (UTC)

They both take their name from the Roman "vinegar cup". They are related by appearance (at least in an anatomist's imagination) rather than by volume. - Nunh-huh 04:55, 15 December 2005 (UTC)
Duely noted, Category Human-based units of measure improved accordingly.--Cybercobra 03:10, 16 December 2005 (UTC)

Capacity of Twisted pair & a Coaxial Cable ?[edit]

  1. .How much data can be transferred at a same time in a "Twisted Pair" & a "Coaxial cable"?
  2. .What is the total capacity those cable?
(User:AlMac|(talk) edited to make it look nicer)

Part of the answer to the question is related to the structure of the data, and packing. Data is being transmitted at the speed of light along the cable, right? It is going two ways at the same time. There are multiple parallel data, like in a TV signal, there is both audio and video, in parallel with each other.

Advantage of one over another is resistance to interference with the primary signals. User:AlMac|(talk) 21:08, 15 December 2005 (UTC)

Assuming you mean in terms of computer networking cable, thinwire (co-ax ethernet) tops out at 10 MiB per second, and twisted pair goes up to (at Cat 6) 1GiB per second - assuming you have the correct hardware on both ends. Ethernet has more information. I'll note that, in principle, there isn't really a difference between the maximum data throughput of the two cable types, but as twisted pair was a much nicer topology, noone bothered designing and standardising aything faster through co-ax. Syntax 02:39, 20 December 2005 (UTC)

MS Word[edit]

My computer froze, I had to shut down, and when I opened MS Word a chunk text in a .doc file was replaced by rectangles ( )! What should I do? Neutralitytalk 04:47, 15 December 2005 (UTC)

See if you can open the recovery file. (Search Word's help to find out where it is, it's different for different setups and platforms). - Nunh-huh 04:52, 15 December 2005 (UTC)
I hope you haven't closed Word yet - doesn't it delete all the recovered documents from the previous session upon exit? It should also offer you the choice of the file as last saved by you (which I would imagine is good), and the automatically saved versions... Enochlau 05:14, 15 December 2005 (UTC)
Darn. I did. However, I managed to recover most of the file anyway but have to rewrite a paragraph. --Neutralitytalk 05:39, 15 December 2005 (UTC)

Universe[edit]

With the galaxy, sun and earth all moving, is it possible to stay still in one spot in space?

  • It depends how many variables you use to define "one spot", if you mean X,Y, and Z coordinates are all kept constant, than sure it's possible-ish, but since the expansion of the universe is modeled in 4D, I'd say that last axis might complicate matters--Aolanonawanabe 16:28, 18 December 2005 (UTC)
You can stay still with respect to any chosen Frame of reference. Whether there's an absolutely neutral frame of reference is perhaps another question. -- Rick Block (talk) 05:10, 15 December 2005 (UTC)
By the principle of relativity, you cannot "stand still" in one place. Not moving and moving with a constant velocity look and feel exactly the same. As Michelson and Morley demonstrated with their experiment, there is no absolute frame of reference by which we can measure whether we are "moving" or "staying still" in space. Enochlau 05:12, 15 December 2005 (UTC)
Determining your position requires a reference point, such as you to the Earth, or the Earth to Sun, or the Sun to the Milky Way. So how are you to determine your position in space? You to the Cosmic Microwave Background? - Cobra Ky Flag of the United States.svg (talk, contribs) 05:16, 15 December 2005 (UTC)
This is a tricky question, and depends on what you mean by "stay still" and "in one spot". Until the acceptance of the heliocentric model, most people would have replied "yes" without second thought (Earth doesn't move, therefore if you stand still, you aren't moving). With the adoption of heliocentricism, the notion of an "absolute center" shifted to the Sun, with various explanations for the motion experienced by everything else (including epicycles). Now special relativity is popular, in which there is neither an absolute center nor an absolute zero speed — but there is a relative zero speed, which is the speed of the observer. So by relativity, you can consider yourself to stay still in the exact location where you are, which of course is practically meaningless. ᓛᖁ♀ 05:20, 15 December 2005 (UTC)
Actually, Eienstein's theory of relativity does not state that everything is relative to everything else, just to certain constants, so yes, it is possible. Max 216.209.153.15 14:09, 15 December 2005 (UTC)

FM radio[edit]

How can i make a radio with household parts, and parts from Old radios, cell phone, and mini tv's?

Building a "crystal set" is suprisingly easy. All you need is a coil of wire, a diode (that's what the crystal was for; now diodes are really tiny and cheap), some earphones, and a capacitor that you can change to tune it to different stations. A crystal set is cool because it doesn't need any power other than the radio waves (but therefore there's no way to turn up the volume). You can probably figure out how to build one just from the Wikipedia article.
Of course, that's only for AM radio. Building an FM radio is a lot harder. A quick Google search turned up this: [36]. —Keenan Pepper 07:00, 15 December 2005 (UTC)
Actually, I just read that it is possible to tune in to an FM station with an AM receiver such as a crystal set. It depends on the circuit having a very high Q factor, and of course the quality won't be that great. It works best if you tune to one side of the FM band rather than the center. See [37]Keenan Pepper 07:18, 15 December 2005 (UTC)

computer simulated machine[edit]

hello

i have heard about in servicing field one machine used for daignosing the fault that is csm or computer simulated machine.

let me know the details

Solar Radiation[edit]

Sun had been radiating enormous amounts of energy since its formation. has it been loosing its mass accordingly?. If so ; Can it be quantified?. What are the effects on planetary orbits , if any?

If not , why so? sombansil

Yes, it has been 'losing' mass (to be correct, converting mass to energy through nuclear fusion). Yes, this mass loss can be calculated, since we know how much energy is produced by a hydrogen-helium fusion reaction, and how much mass is converted to energy during this reaction. Taking an estimate of the total energy output of the sun over its history, we can estimate how much mass it has 'lost'. However, compared to the total mass of the sun (1.9891 x 1030 kg) the mass decrease is virtually negligible, and certainly not enough to have a visible effect on planetary orbits.
Addendum: it also loses mass through solar wind. From that article:
Approximately 1×109 kg/s of material is lost by the Sun as ejected solar wind, about one-fifth that lost due to fusion, which is equivalent to about 4.5 Tg (4.5×109 kg) of mass converted to energy every second.
QuantumEleven | (talk) 10:09, 15 December 2005 (UTC)
Just a quick reminder to do your own homework. "If not, why?" is usually a dead give away that you're doing someone's homework. To the poster, instead of asking a homework question verbatim, just point out where you're having difficulty. --Quasipalm 18:22, 15 December 2005 (UTC)

Installing SATA and ATA drives together[edit]

Is it possible to mix (install together) SATA and PATA hard drives in a single system? If so, how should I do it? Is it a good idea? Thanks in advance. 61.94.149.177 10:28, 15 December 2005 (UTC)

I've got such a setup and it works. The very fact that there are motherboards with both SATA and PATA connectors should be a sufficient indicator that it should work. Since SATA is fairly new there may be some problems with that, but I don't see how the combination could cause any problems. If I'm not mistaken, the access of the drives is the same, irrespective of whether it's a SATA, PATA or SCSI, because the translating is done on the drive/interface itself. (Not sure if I put this right.) DirkvdM 11:57, 15 December 2005 (UTC)
  • All mobos I've seen that use SATA also have some standard ATA connectors so that you can plug in CD-Rom drives, etc. (AFAIK almost all SATA devices are hard disks). You should be able to add standard ATA HDs to those connectors without any problems. --Bob Mellish 16:57, 15 December 2005 (UTC)

Water airplane crashes[edit]

Have there been any crashes of commercial airliners into bodies of water (lakes, oceans...) where (some) people on board have actually survived? I know that there are quite a few land crashes with few or no casualties, but I can't think of any water landings where not everyone was killed... — QuantumEleven | (talk) 12:44, 15 December 2005 (UTC)

See this link. 61.94.148.181 14:01, 15 December 2005 (UTC)
Thanks! That's a pretty exhaustive list, but sadly confirms my suspicions that very few large jet aircraft have survived a water landing... — QuantumEleven | (talk) 14:55, 15 December 2005 (UTC)
After checking out that list, it doesn't seem to me to be that dismal of a figure. Many low-passenger-count flights had 100% survivor rates, and many large-passenger-count flights had minimal fatality rates. I guess it's all about perspective, though.

Dental x-ray[edit]

This question no verb. —Keenan Pepper 16:40, 15 December 2005 (UTC)

What is histrionic personality disorder?[edit]

You do realize this is an encyclopedia, with over 800,000 articles covering a broad range of topics? I suggest you look it up. -- Rick Block (talk) 16:51, 15 December 2005 (UTC)

clean or unclean?[edit]

Try clean and/or unclean. Thryduulf 14:35, 15 December 2005 (UTC)

Crushed stone[edit]

If you take one cubic metre of stones and crush them in a crusher to produce finer aggregates, what will the volume of resulting aggregates

 a)>1 cubic metre
 b)=1 cubic metre
 c)<1 cubic metre

Thank You

Depends on the size and shape of the original stones, I'd say. For example, if you start with a single cubical stone with one meter edges, the answer would probably be a. If, on the other hand, you start with spherical stones 50 cm across, packed into the same one meter cube (8 will fit exactly), the answer is almost certainly c. And of course, if you only measure the actual volume taken by the stones, not counting the spaces between them, then the answer is always b by definition. --Ilmari Karonen (talk) 14:21, 15 December 2005 (UTC)

The answer is (c), your homework is to explain why. Physchim62 (talk) 18:04, 15 December 2005 (UTC)
I'd support (c) too, but I'm not sure. If I'd want to know this, I'd take a vesel with a scale on its side, put some breakfast cereals in it, write up the volume from the scale, crush the cerial to very small bits (this is the difficult part), and see if the result will fill the vessel to a higher or lower level. Of course, stone could behave differently. – B jonas 19:11, 15 December 2005 (UTC)
I would have gone for c) too, but notice that Ilmari has already refuted that. Very clever! (Though the last bit is a bit corny). But I'm sure one could generalise this in a formula. Actually, I believe there is a form of geometry that deals with just this sort of thing, but I can't think of the name. Topology doesn't seem to be it. DirkvdM 08:04, 16 December 2005 (UTC)
In fact if you consider the stones to be close-packed spheres at all stages of crushing, the answer is (b), the stones occupy just over 74% of the volume regardless of radius. See also Kepler conjecture. Physchim62 (talk) 10:22, 16 December 2005 (UTC)
...except that this holds only if they are all the same size (the packing generally gets denser if there are stones of various sizes), and ignores possible extra gaps at the edges of the container (which will on average be roughly proportional in volume to the radius of the smallest stones). Not to mention the fact that real stones are rarely spherical, especially not after crushing. And then there's the fact that randomly packed granular materials may not even have a constant volume — they may settle (or expand) when shaken. —Ilmari Karonen (talk) 21:38, 16 December 2005 (UTC)

just a question[edit]

I was talking with a teacher and we came across the fact that a green bean could be a vegetable or a fruit and we were wondering which one it is. It is not a root or a leaf however it has beans and that means that they can reproduce and regrow. Therefore i just need to know whether beans are a fruit or a vegetable. Thank You, Melinda

A fruit is a scientific definition, while a vegetable is a conventional one. Consequently, the two are not mutually exclusive and a given object (say, a tomato) can be both. A green bean certainly meets the conventional definition of a vegetable, and beans have been legally labeled such, but as a legume, it also meets the definition of a fruit. — Lomn | Talk / RfC 18:47, 15 December 2005 (UTC)
So alfalfa is also a fruit? So what is the classification of non-legumes like celery?
No he is refering to the beans themselves being fruit. Alfalfa is eaten as the shoots of the plant not the fruiting body so it is a vegetable, not a fruit. If you read Fruit, it explains a fruit is essentially the part of the plant that grows from a fertilised flower and contains the seeds of the plant. If a vegetable is a pert of a plant that does not contain seeds then it is not a fruit. --Martyman-(talk) 22:43, 15 December 2005 (UTC)

Spandex[edit]

Does spandex, lycra, or nylon, contain latex?

This is an encyclopedia. Have you tried looking these things up? -- Rick Block (talk) 20:00, 15 December 2005 (UTC)
I think spandex, lycra, and nylon are all synthetic polymers, whereas latex comes from a plant. —Keenan Pepper 20:38, 15 December 2005 (UTC)
If you use the technical definition of "latex", it's quite possible to make a latex of nylon, by producing very fine particles of it, suspended in water.--Joel 13:49, 21 December 2005 (UTC)

technology developed originally for the military but now used in our homes[edit]

Hi everybody !

I´m a Brazilian journalist, working for a Science and History monthly magazine.

Right now, I´m doing research to write an article to answer the question "Which products originally invented for the military are now used in our homes ?" (For instance: canned food, the internet, etc.)

I would be most grateful if you could send your answers to this question. I also would be grateful if you could provide names and e-mails of specialists (historians, researchers, sociologists, political scientists, etc) who could be interviewed by e-mail about this subject.

Thank you very much.

Roberto

--201.37.160.41

You're not, by any chance, writing for Superinteressante, are you? ☢ Ҡieff 04:57, 16 December 2005 (UTC)

You might also find useful info in the History of Space Exploration. Many products and services originally developed for astronauts, such as powdered orange juice, powdered milk, microwaveable instant meals, subsequently found their way into every home. Related to that, look at what has happened with Spy Satelites. Today there are several commercially available views of planet earth connected through the Internet, where anyone can see detail that a few years ago was only available to the military.

Some products and services were invented jointly for the military and for a nation as a whole.

  • The Internet was created by the military but it was not solely for the military, it was to provide communications with all sectors of government, business, academia, society, and be reistant to disruption in a disaster. We saw this concept fail in the Hurricane Katrina disaster, at least for the people on the ground there.
  • The US Interstate System had a similar joint purpose. At the time of WW II, many of the roads across the USA were not strong enough for the military to get from one side of nation to the other in a crisis, heavy equipment had to go by Railroad. But with the Interstate System, the National Guard and Reserve could be decentralized in many communities, and rapidly get to where they needed. But the financial success of the system needed it to be used by the mass public. It was not just for the military.
A lot of research into products and services for the military, can be made less expensive per unit person, if the beneficiaries of the work can be extended to the larger population. We see this in protection against various medical risks. The troops need to be vaccinated against a spectrum of diseases and biowarfare risks, then if the threat materializes, populations of whole nations also need protection.
It has been a while since I saw what progress was being made on cloning limbs to repair self. It may be that US politics has shut this down. The theory was that before going into harms way, troops blood samples would be stored some place, then after they exposed to radiation damage, or lose an arm or a leg, the blood samples be used to grow replacement parts for the injured soldiers sailors airmen, and because it was from their blood, their body would not reject the replacement organ.

User:AlMac|(talk) 21:17, 15 December 2005 (UTC)

Have a look at the history of computing: one of the first embedded computers was the guidance computer for the Minuteman missile: later versions, along with the Apollo program, pioneered the use of the integrated circuit. SAGE was one of the first real-time computer applications ever built, and pushed the industry along enormously. Heck, Colossus and ENIAC were both used for military purposes. Another classic example of WWII technology applied to home use is the microwave oven, the core of which was the cavity magnetron used in radar.
HTH. --Robert Merkel 21:52, 15 December 2005 (UTC)
  • GPS, for a loose definition of "used in the home". --Bob Mellish 21:57, 15 December 2005 (UTC)
    • Swords to ploughshares is the term you are looking for, though it's currently fairly sparse. Anyone wanna help with that--Fangz 22:33, 15 December 2005 (UTC)

Many millioms of people died in WWI and WWII and I would not try and justfie the loss of life but think where we would be now had it not been for their sacrifice. Next time you jet off for a week end holiday just remember it is only just over 100 years ago since the first powered flight. Without those wars it is unlikly that aircraft would have developed passed the wood and string stage at this present time. I would hate to try and work out the percentage of tecnological advances we enjoy today that wern't attributable to our need to kill ourselves or to protect ourselves from being killed by our fellow man. With great regret I say long live testosterone.--Eye 16:01, 18 December 2005 (UTC)

Not exactly used in the home yet, but used all over the place in civilian life, is Radar. Sewe if you can find the book "The Invention that changed the World" about how RADAR was invented, There's fascinating stories in there about how Axis and Allies used different wave lengths, and how they figured that out so they could do jamming. Anyhow, after WW II, RADAR made the Airline industry as we know it today, and great advances in Astronomy, and safer highways. User:AlMac|(talk) 07:45, 20 December 2005 (UTC)
Check out literature on the History of science. I saw on a recent Science TV channel how Leonardo da Vinci was employed in the development of Mathematics to figure out how to get medieval weapons of warfare to send forerunners of artillery shells to the precisely correct targeting. While that math has advanced to more superior weapons, it has also become available to civilians for other purposes. Most all math today came about thanks to either warfare or early business book keeping. User:AlMac|(talk) 07:51, 20 December 2005 (UTC)
One of the first documents published by Galileo was a manual for how to operate what he called a "Military Compass" which was something he made in his workshop that was similar to a calculating instrument called a slide rule, something very popular with engineers prior to major development of personal computing. User:AlMac|(talk) 07:55, 20 December 2005 (UTC)

Herb Robert Information[edit]

I am doing a science project on The Effects of Herb Robert on Acne Bacteria. i need more information on Herb Robert. The pigments in the leaf that makes it what it is. i am trying to find out what elements make up Herb Robert.

The wonderful thing about Wikipedia is that you can type in whatever you need information about in the little search box on the left of your screen and hit "go." For example, try typing "Herb Robert." It will take you here. Especially check out this link. I myself know nothing about botany, so that's all I can do. Now to slink back to the Humanities desk... --zenohockey 02:18, 16 December 2005 (UTC)

Email[edit]

How do people send me email from fake addresses?

If you've read E-mail, the basic technique is to write a mail user agent that supplies a forged "from:" header. SMTP is a text-based protocol, and it is quite easy to manually type an entire email message (including whatever "from:" header you'd like) using a raw SMTP connection. The basic insight is that the address information used for the delivery of the message is separate and distinct from any header content you typically see in your mail client. -- Rick Block (talk) 22:57, 15 December 2005 (UTC)
You should read the RFC about the SMTP protocol there are even some examples in it. The destination mail server can be found if one does a nslookup with type=mx on the destination domain. helohe (talk) 09:49, 16 December 2005 (UTC)

December 16[edit]

tummy tuck and headaches[edit]

I am curious if anyone has linked having abdominal surgery, specifically tummy tuck with causing headaches. Once the tummy has been cut and sewn tight to reduce the area of tissue the torso is then pulled forward into a forward flexive state. Pulling the torso/thoracic into flexion will pull the head into flexion which then puts so much more pressure on the "righting reflex" which causes the cervical musculature to go into hyperextension, thus creating major tension headaches. I have been experiencing this since July, 2005. I would love to speak with anyone on this subject. www.giese@pbcc.edu

Weather[edit]

Is there a website besides Weather Underground, that has historical weather information on a daily bases?

How far back and for which country? --Canley 04:06, 16 December 2005 (UTC)

I was thinking maybe 10-15 years and in the U.S.

The Old Farmers' Almanac site has a place where you can look up the information. Do you need it in some sort of specific format? --AySz88^-^ 05:23, 17 December 2005 (UTC)

wet wing design[edit]

what is the meaning of wet wing design in aviation? what r its advantages?

Ok, basically there's two main ways that airplanes store fuel: in tanks or in "wet wings". Most aircraft store fuel in the wings, some simply have tanks in the wings like the gas tank in your car. Other, so-called "wet wing" aircraft, seal the entire wing and use that as a tank. Thus the metal on the outside of the wing that defines the wing is the same metal thats holding the fuel. This is advantageos because it means that you don't have to carry extra metal for a separate tank inside the wing, and you can put fuel into every nook and cranny of the wing which means you can store more. However, wet wings are much more prone to leaking and getting them manufactured right can be really tricky. Thus, they're mostly found on larger commercial aircraft, not general aviation aircraft. -User:Lommer | talk 07:50, 16 December 2005 (UTC)
Should we have an article on this? —Keenan Pepper 20:45, 16 December 2005 (UTC)
Yes. I'm not entirely sure where to put it though (i.e. what to call the article). I've written most of Aviation fuel, and it would be closely connected with that. Perhaps I'll write an article on aviation fuel systems? Might be a bit hard to find but with appropriate redirects it could work. -User:Lommer | talk 22:48, 16 December 2005 (UTC)

Bird that starts with letter X[edit]

What is the name of a bird that begins with the letter X? Thanks for any help. I'm stuck.

Nullaby (which I think is made up, but I'm not sure) mentions the Chinese Xu Bird (which I think is also made up, but I'm not sure). Jasongetsdown 03:47, 16 December 2005 (UTC)
According to the OED there is a bird called a xeme, "a bird of the genus Xema; a fork-tailed gull". --Shantavira 11:42, 16 December 2005 (UTC)
You might have more luck if you moved the question to the Language reference desk. JackofOz 22:58, 16 December 2005 (UTC)

Annoying spyware[edit]

Something annoying starting to occur on my PC. On my Internet browser, when I click Google search results, the page goes to MorwillSearch.com. This doesn't happen with other links. I go up to the URL, press enter, and can access the page I intended, but this is frustrating. I've run AdAware and Spybot, but to not avail. Advice? Neutralitytalk 04:35, 16 December 2005 (UTC)

You might try HijackThis. -- Rick Block (talk) 05:11, 16 December 2005 (UTC)
Yes. Hijack This will solve this problem. But be careful which lines you delete when you run it, and make sure you save a backup. Usually it's pretty easy to see which lines should be excised. (any containing Morwillsearch.com, for a start) Proto t c 10:43, 16 December 2005 (UTC)
Most likely this is a browser helper object (BHO) if you are using Internet Explorer which detects certain URLs and words to redirect you to sponsored links. If any strange toolbars have appeared recently, see if you can uninstall it. Otherwise, take the advice of the others and use HijackThis and delete the appropriate line. This will be labelled 'BHO', but remember Proto's advice! Archer7 17:52, 18 December 2005 (UTC)

Heating car in winter[edit]

Does it burn extra gas to heat a car? If I leave the heater off, will I get better milage? --24.31.29.171 04:53, 16 December 2005 (UTC)

No, because the engine produces so much waste heat anyway. Usually the radiator pumps the extra heat to the outside of the car; when you turn the heater on some of it is directed inside instead. —Keenan Pepper 05:05, 16 December 2005 (UTC)
Considering how hot it gets in a car when you turn the heating up all the way, I wonder how much energy is lost. The efficiency of getting the heat into the car is probably very low and a car is badly isolated and moving fast, which causes a lot of heat loss. If, despite this, you can still get the interior of a car so hot (with just waste energy!), then the energy consumption of a car is probably way higher than the heating of an average house. Then again, one doesn't drive a car constantly (usually about one hour per day). So I wonder what consumes more energy, driving a car for one hour or heating a house for, say, the equivalent of 8 hours in a temperate climate (no heating in summer and low at night). Is there a good site for energy footprint of not just cars and house heating but also household appliances and such? I can't find one, most things I find are cute little quizzes and no simple info. How hard can this be?
However, my search did teach me this little tidbit: "If everyone in the United States made sure their car tires were adequately inflated (through weekly checks), gasoline use nationwide would come down by 2 percent." And keeping the car tuned in other ways can add another 10% efficiency (for the car that is). Of course, having a car that has an engine that's just big enough for what you need will make the biggest difference - in most cases (especially in the US where huge cars are popular) I assume less than half the 'horsepower' would be sufficient.
One of the best lists I've found so far is this one: [38], although, ironically, it doesn't include the car. Somewhere else I read that a typical electric car uses about 20kWh of energy to drive 100km. Suppose a commuter drives 50 km per day, 20 days per month. That would mean 200kWh per month. The table gives about 1000 kWh per month, which is 5 times as much. But one doesn't normally have all those things and a comparison with an electric car isn't entrirely fair (also because they're usually lighter than 'normal' cars). And I haven't included shopping (the frequent stops in city traffic consume loads of energy), so I suppose that for an average household the car consumes about 1/3 of the energy. No wonder a minor thing like keeping the tires appropriately inflated can make such a big difference. DirkvdM 10:10, 16 December 2005 (UTC)
Me again. Found this (from [39]: In the US, cars and light trucks account for 40 percent of the nation’s oil use.
It depends. In most cars, no. In some (a very small few), yes. In most cars the heat surplus is big enough, but there are some efficient cars where it isn't enough (low-power highefficiency diesels, hybrids etc come to mind) where the heat output, at least in cold conditions, just isn't enough (at least to heat the car rapidly - even though the heat output is sufficiently big to maintain the temperature, it might not be enough to heat the car in less than 100 km...), and an extra, electric, heater also is installed. Using this would of course mean raised fuel usage. TERdON 00:20, 19 December 2005 (UTC)
The other exception is the early Volkswagen Beetle, which has a rear-mounted, air-cooled engine, which made the prospect of piping hot water from it a little too difficult during the first few models. These had a gasoline-powered furnace in the cabin, which (according to some old folks I talked to years ago) ran the risk of explosion if it was turned on without ignition. --Joel 14:01, 21 December 2005 (UTC)

meaning of cephalopodes[edit]

You'll be wanting our article on cephalopods. Physchim62 (talk) 10:31, 16 December 2005 (UTC)

Light[edit]

How is diffraction different from refraction?

They differ in several ways; but they're similar in that they can both be easily looked up in Wikipedia. See Diffraction and Refraction. --David Iberri (talk) 12:19, 16 December 2005 (UTC)
The colors of light reflected from the bottom of a CD are the result of refraction from the closely spaced grooves. The colors of light spanning the sky in a rainbow are the result of diffraction through myriad tiny raindrops. In the first case we see color because different wavelengths are selected by the groove spacing; in the second, because different wavelengths are dispersed to different positions in passing through the water droplets. Both depend on wave mechanics. --KSmrqT 12:53, 16 December 2005 (UTC)
  • Other way around - diffraction from a CD, refraction+dispersion for raindrops in rainbows and prisms. --Bob Mellish 14:19, 16 December 2005 (UTC)

microbiology[edit]

... which, believe it or not, we have an article on! — QuantumEleven | (talk) 13:13, 16 December 2005 (UTC)

wat kind of question is that ???

  • Not a question. Merely a word. Halcatalyst 05:38, 19 December 2005 (UTC)

SAS date reference[edit]

Why does SAS (developed by Jim Goldsmith some thirty years ago and now used practically everywhere) use Midnight on the 1st of January 1960 as their date reference point?

ie that date is defined as zero, dates before are negative (31st december 1959 is -1) and dates after are positive (2nd jan 1960 is 2). it also counts hours and minutes and seconds from midnight on that date. So it must be significant in some way. Any ideas anyone? Cheers. James. --62.49.11.11 15:35, 16 December 2005 (UTC)

  • You seem to have made a mistake. If 1960-01-01 is day 0, then 1960-01-02 would be day 1 (assuming days are numbered serially). --Juuitchan

SAS Reference date (correction)[edit]

sorry it was James Goodnight. Apologies. james (again)--62.49.11.11 15:50, 16 December 2005 (UTC)

  • Well I'm not sure what SAS is (is that the same as SAS System?) but 1st Jan 1960 was probably an epoch date on the first system it was implimented on (or if not, was chosen as an epoch date by the programmers), in the same way that 1st Jan 1970 is the Unix epoch. Generally epoch dates don't have any special significance - they just a handy date/time to start counting from. --Bob Mellish 16:03, 16 December 2005 (UTC)

Viewable area in LCD monitors[edit]

In CRT monitors, if we feel 13.75 inches (in a 15 inch monitor) as big, it would be possible to adjust the size to say 13 inches. Will the same be possible in a LCD monitor? Can we change the viewable area in LCD monitors and laptops?

The fact that you don't have to fiddle with the screen size on an LCD is usually considered a feature. Jasongetsdown 19:24, 16 December 2005 (UTC)

(The original asker of the question) Do you mean that it is not possible to reduce the size? Just another query, Is it possible to do that in windows if not in the monitor?

In principle, sort of. It depends on the electronics that are attached to the screen - these are required in a CRT, and not in an LCD, so probably not. On the other hand, a software appraoch would work for an LCD - where you define the outer (say) 100 pixels to be black, and tell the OS not to use them. The only OS I know that supports that kind of wacky configuration is the GNU Hurd - which is very much not a 'suitably for general use' OS. Syntax 02:48, 20 December 2005 (UTC)

I have a definition, but need the word[edit]

The definition is:

The property of a substance to retain heat.

I tried to find the answer on google by typing in the definition, but that didn't get me anywhere. I also tried dictionary websites, but I could't find one that would let me find a word by giving the definition.

Latent heat ?? JackofOz 22:03, 17 December 2005 (UTC)

Lens tissue[edit]

What material composes the lens of the eye? What is its index of refraction? While I'm at it, what are the indices of refraction of the aqueous humor and vitreous humor? —Keenan Pepper 21:45, 16 December 2005 (UTC)

The lens is made–mostly–of crystallins. (There are three families of crystallins: the alpha-, beta-, and gamma-crystallins.) I couldn't tell you refractive indices off the top of my head, however. TenOfAllTrades(talk) 22:04, 16 December 2005 (UTC)
  • The eye's lens varies from n=1.406 in the centre to n=1.386 at the edges; as well as its lens shape, it also focuses light by being a GRIN lens. The aqueous humor is n=1.336 and the viterous humor n=1.337. The cornea has n=1.376. All values from Chapter 5 of Hecht's Optics. --Bob Mellish 01:18, 17 December 2005 (UTC)
Wow! Gradient index optics! I had never even heard of that. And I guess it makes sense that the two humors have the same index of refraction as water, because they're mostly water. Thanks for the great answers! —Keenan Pepper 03:18, 17 December 2005 (UTC)

is matter made of 'light'?[edit]

I read somewhere that the basic building blocks of matter where photons at rest, and i think that's kind of silly, but i'm no physcist nor mathematician so i dunno... but it sounds like new age BS.

That is silly. The basic building blocks of matter are quarks and leptons, as far as we know right now. In ordinary matter, up and down quarks form protons and neutrons, protons and neutrons form nuclei, and nuclei plus electrons form atoms, and different kinds of atoms form molecules. -- SCZenz 23:12, 16 December 2005 (UTC)
It isn't all that silly... nobody knows what matter is composed of at the most fundamental level. Quarks may be composed of preons, and all our observations may be skewed by symmetry breaking. We have weird theories like superstrings or the single time traveling electron; matter as "frozen light" is tame in comparison if one accepts mass-energy equivalence. The idea doesn't really help to explain the rest of physics, though, so it just amounts to idle speculation. ᓛᖁ♀ 23:26, 16 December 2005 (UTC)
Btw, how is that theory called that tries to describe everything (including matter, etc..) only as a fraction in multidimensional space-time? (based on the Kaluza-Klein theory if I remember). helohe (talk) 23:36, 16 December 2005 (UTC)

what would that theory u talk about imply?

Try theory of everything, if that fails, try ten-dimensional hyperspace, a little bit of a tangent, but worth a look--Aolanaonwaswronglyaccused 16:19, 18 December 2005 (UTC)

December 17[edit]

A good way to remove laquer from brass?[edit]

I want to do this to a lamp. Thank you for any help.

  • A google search for remove lacquer brass returns a lot of hits; one or more might be useful. --jpgordon∇∆∇∆ 03:41, 17 December 2005 (UTC)

Walking Through Walls[edit]

This is as much a scientific question as it is a philisophical one, but I was hoping that you could help me find info on something. I read that a long time ago, Chinese monks used to practice the art of walking through walls. I knwo this sounds crazy, but if you have any knowledge of quantum physics then you may be able to grasp this theory. I believe it was once on an old Discovery Channel show, so if you could maybe find an archive of that. I would greatly appreciate any help you could give me on this! Thanks!

--71.33.116.18 02:24, 17 December 2005 (UTC)

I believe the quantum mechanical concept you are thinking of is quantum tunneling. When you're done reading that look up classical mechanics. The only forces you or I will ever experience are those which obey the laws of classical mechanics. The wierdness of Quantum mechanics can only work for individual atoms or subatomic particles. Electrons can tunnel inexplicably, people cannot. Its still fun stuff though, read up :) Jasongetsdown 02:56, 17 December 2005 (UTC)
Or maybe these walls were thin and made of paper, like shoji? =P —Keenan Pepper 04:57, 17 December 2005 (UTC)
Buy the Mr. Tompkins books for a quick overview of quantum mechanics aimed at the casual reader. 82.26.164.168 06:15, 17 December 2005 (UTC)
Point: Old Chinese monks could most certainly not walk through walls, contrary to the legends. Quantum mechanics suggests that there is a tiny, tiny, tiny chance that such a thing could happen, but beyond that one gets into the fuzzy realm of religion. Which I leave up to you. --George 08:19, 17 December 2005 (UTC)
To combine the above with what Jasongetsdown said. In dividual particles may move through a wall (then again, what is a wall at that scale?). And people are made up of particles. But they'd have to all do this at exactly the right moment for a something a s big as a human to move through something as thick as a wall. I've heard of an exam question being to do the maths on this. So there is a chance that that could happen but it's immensely small. So I suggest you don't start trying. (Hmmm, didn't I give a similar response earlier somewhere?). DirkvdM 10:43, 17 December 2005 (UTC)
It's cute to conflate the mystical-seeming logical contradictions of ancient Eastern philosophy with the logical contradictions of modern quantum physics, but the truth is that most feats attributed to ninjas and sects of monks were either feats of strength or slight of hand, which seemed magical to an observer who could not imagine the amount of lifelong training these experts endured. If a monk appeared to walk through a wall, it was probably a feat of misdirection or 'stage magic' on a level probably exceeding David Copperfield or David Blaine, which was put on for the purpose of inspiring the religious faith of observers or else to inspire donations to the temple. -72.144.236.150 06:00, 20 December 2005 (UTC)

Entry into programming[edit]

Hi, I was wondering if anyone could recommend some books or web sites that could get me into computer programming, on a very, very basic level. It looks very interesting and I'd like to look into it, but the sections in all the bookstores look very daunting; I wouldn't know where to begin. I'd appreciate your help, thanks. --03:00, 17 December 2005 (UTC)

Pick something that interests you and keeps your interest. You might want to go for languages with visual interfaces so that you can see your results quickly. --HappyCamper 03:02, 17 December 2005 (UTC)
Step 1) Pick a language to learn. Scripting languages, such as Python, Ruby and Perl, to name three prominent examples, are especially good for novice programmers. I can personally recommend Python, but Ruby has some momentum behind it, and Perl is an old hacker favourite.
Step 2) Find resources on your language. There will usually be a resource page on the language's website (look for anything labelled 'beginners' or 'tutorial' or similar), and googling will definetly result in a few good hits.
Step 2.5) There will be at least one mailing list for newbies. Sign up, try and understand the discussions, and if you get seriously stuck on something, ask a question on there.
Setp 3) Play around! Nothing beats some practical experience when learning to program. Do any examples in the tutorials you read, try out any little snippets in there, and try and extend them to do more useful stuff. You know all those irritating little tasks that only take about 30 seconds but you have to do constantly? Automate them in your language - you'll be rewarded with valuable experience, and cut those 30 seconds to 5. (Of course, if you're a hardcore MUDder/gamer/sysadmin/etc like my friend here A Lee-Yas, this is probably why you wanted to learn a programming language in the first place :))
HTH, --Sam Pointon 04:18, 17 December 2005 (UTC)
I second the recommendation for Python. Look under "Introductions for non-programmers" here: http://www.python.org/doc/Intros.htmlKeenan Pepper 04:52, 17 December 2005 (UTC)
If you are interested in making simple programs as a hobby for Windows, I recommend the Microsoft Visual Studio Express Editions. At the moment they're free and there's lots of help on getting started on MSDN. However, Python, Ruby and Perl may be better for contributing to open-source projects and more complicated applications.

About petroleum[edit]

why coal should be use to produce the petrol?

Floating[edit]

How to people such as David Blain and Criss Angels float in the air???

It's really simple. They just stand on the edge of one foot, at a certain angle to the camera (or live audience) so you can't see the edge that's touching the ground. The hard part is getting the angle just right, and acting up a storm to distract people from your feet. —Keenan Pepper 04:44, 17 December 2005 (UTC)
It's called Balducci levitation. —Keenan Pepper 04:45, 17 December 2005 (UTC)
Indiana Jones came across something similar in the second or third film. DirkvdM 10:45, 17 December 2005 (UTC)
It was the third film, where Indy must make a "leap of faith" and step into what appears to be nothingness above a huge chasm. But he does step, and when he does finds himself on a bridge painted or carved of stone to look like a cliffside on the other side of the gorge. --Articuno1 01:23, 18 December 2005 (UTC)
  • Mind you, the Balducci levitation is just one of the methods magicians can float. David Blaine used a combination of Balducci and standard wire suspension. I'm not familiar with Chris Angel(s). But there's also someone (I believe it was Corey King) who has a method to float which can be viewed from both the front and the back. The best thing to find these things out is to surf the net and forums where people discuss magic or simply visit your nearest magic shop and actually buy the effect (what most people refer to as the "trick"). Also, remember that magic is not just knowing the method behind the "trick", you also need to know how to present it in a way that entertains your audience. - Mgm|(talk) 10:28, 18 December 2005 (UTC)

what are the side effects of divalproex[edit]

See Valproic acid#Side effects. —Keenan Pepper 06:07, 17 December 2005 (UTC)

carbon dating of sea shells & tree fossil.[edit]

See radiocarbon dating. Do you have a specific question? —Keenan Pepper 06:08, 17 December 2005 (UTC)

vitamin pill diet[edit]

Hello, this is KeeganB. What would be the danger of going on a diet restricted to vitamin pills and the occasional bit of solid food?

Possibly bad for the stomach, depending on how much solid food you ingest. This was discovered when a low-weight diet was sought for astronauts. Your tummy needs something to chew on, so to say. Also, vitamins aren't quite the only thing the body needs, so it again depends on the solid food; how much and what does it contain. My advise: stick to a well balanced diet of solid food and throw the vitamins out the window. Along with any other pills, unless you've got some 'disorder'. What is the reason for the question? DirkvdM 10:50, 17 December 2005 (UTC)
That would depend on just how occasional that "occasional" bit of solid food is, and what it consists of; you would also need to consume water to offset the water lost in urine, perspiration, feces, and expired air. A normal diet consists of much more than vitamins; it consists of minerals, protein, fat, and carbohydrate, as well as vitamins. You need to consume enough calories to maintain your basal metabolic processes, enough of the essential amino acids in protein to maintain lean body mass, enough minerals to maintain skeletal bone density and electrolyte balance. There are also presumably many unknown chemical constituents in normal food that contribute to health. You'd be better off consulting with a dietitian than relying on propaganda from the nutritional supplements industry.--
Mark Bornfeld DDS
Brooklyn, NY 16:08, 17 December 2005 (UTC)
I deliberately didn't mention specific nutrients because the list would be endless, and as Mark says, there are probably also lots of chemicals we need but don't know about yet. Have any experiments been done with people or animals getting a diet of just he things you mention? Of course, this has been done to some extent with astronauts (though so strictly?), but a lack of trace elements and such will probably only have an effect over a longer period of time. I know the Soviet Union did lots of such experiments because they focused on long term stays in space (as a result of which Russia is now considered the expert country for this sort of thing). But did they take it this far (meaning consumption of nothing but water, assorted vitamins, minerals, carbohydrates etc)? DirkvdM 08:51, 18 December 2005 (UTC)
I agree with the previous comments and would add a few pts:
  • Many synthetic vitamins are in forms which are difficult to absorb or use and may actually be of little practical value. For obvious reasons, they don't starve people and just give them vitamin pills to test how effective the vitamin pills really are.
  • The full digestive tract needs to be exercised to continue to work properly. Fiber, for example, is important for colon health.
StuRat 12:56, 22 December 2005 (UTC)

Suicide?[edit]

I have heard that some animals, apart from human, do kill themselves.

I want to know

1.It is ture? 2.Why are they doing this? 3.Can you give me an example animal name?

Thanks

Hmmm, that's going to get quite philosophical. Many social insects readily sacrifice themselves to defend their hive; other social animals will do the same on occasion. Is this suicide? What about salmon, who die after travelling upstream to breed? The example of "animal suicide" you're probably thinking of is the lemming; this myth was apparently spread by a Walt Disney wildlife film.
Salmon have little choice, I believe. The change happens to them irrespective of what they do (not sure, though). But soldier ants indeed sacrifice themselves for the hive. And some mothers let their kids eat them (again, more common with little critters than mammals). And the reason for that would be (as always) evolution. If one mother had a genetic 'abnormality' that made her let her kids eat her and the kids thus had a better chance of survival, that genetic 'abnormality' might spread and become 'normal' (whatever that is). Of course, if the mother would otherwise have had many more offspring (in other words if other mothers did that and thus got more offspring) then it might not work. DirkvdM 10:58, 17 December 2005 (UTC)
Whale beaching behaviour may also be suicide, especially since the same whales have been observed to beach themselves repeatedly after being carried back to deep water. For complex creatures, like whales, they may suffer from "brain malfunctions", like we do, that cause human suicides. An evolutionary exlanation is also possible. Old, sick or weak whales, which can't reproduce or contribute to the pod, may kill themselves to avoid consuming food others could eat. Thus, they are helping their genetic relatives pass on their genes more than they could if they continued to live. This may be a concious decision, or they may just have an instinct to swim toward to beach when they feel old, sick, or weak. For most animals, this isn't necessary, as predators or others of their own species will kill off the old, sick, and weak. Sharks might do this, for example. If this theory holds, then suicidal behaviour would be most common in "gentle" animals at the top of the food chain, like whales amd humans (OK, semi-gentle). StuRat 12:47, 22 December 2005 (UTC)
I believe the beaching is (always?) done by whole groups of whales, not by individuals. So that would invalidate your reasoning. Even if the entire group were weak, they'd be helping other groups, not their relatives. DirkvdM 13:20, 23 December 2005 (UTC)

Designing an experiment to show that an increase in temperature infuences the release of red pigment from beetroot. Any ideas???[edit]

Any ideas or thoughts would be greatly appreciated. Thanks. —Preceding unsigned comment added by 86.131.123.199 (talkcontribs)

Seems like a fairly simple homework question. Put some beetroot in cold water and at the same time put some beetroot very hot water and watch to see what happens. --hydnjo talk 14:51, 17 December 2005 (UTC)

Who is E. Duffy[edit]

Hello. I was reading biodiesel where I saw "E. Duffy". Does someone know for what does the "E." stand for ? I think that Duffy should not be a redirect but rather a disambiguation page, do you agree ? Thanks in advance--Youssef 11:32, 17 December 2005 (UTC)

I tried Wikiwax (typed in "Duffy" and waited) and although Wikipedia has two articles on E. Duffy's, neither of them had anything to do with biodiesel. I don't think a disambiguation page should be created, disambiguation pages are not search tools - they exist to navigate between articles that would otherwise share the same title. Ideally we could use the List of people by name, but it needs lots of updating--Commander Keane 11:58, 17 December 2005 (UTC)

About a 15" LCD monitor[edit]

Do any one of you use 15" LCD monitor? I just want to know what is the resolution you use. Do you use 1024 x 768? Is it comfortable? And, what is the distance between your eyes and the monitor in the case of a 15" LCD monitor?

One of the terms you want to look for when picking out an LCD monitor is Native_resolution. This is the resolution that each pixel on the LCD represents one pixel being sent to it by the video card/motherboard. This and many other answers can be found at Liquid_crystal_display. A 04:36, 18 December 2005 (UTC)
Clarifying the answer above — an LCD monitor is designed to run at one specific resolution (you can read all about it at Native resolution, and unless you have a very good reason you shouldn't run it at any other resolution. For most 15" monitors, the native resolution is 1024x768, however you will definitely want to check your monitor's documentation.
And as for the distance, that varies from person to person, on how long you use it every day, how good your eyesight is... try and do what feels most comfortable for you, view it at a distance where you can read anything on the screen without straining your eyes or squinting. — QuantumEleven | (talk) 10:21, 19 December 2005 (UTC)
I'm using a 17 in LCD monitor, but I thought I'd still answer this question.
LCD monitors have a maximal resolution, on which they can be used optimally. Lower resolutions than this are still readable but don't look nice enough; higher resolutions shouldn't be used. For my monitor, it's 1280x1024 (as this is an 5:4 shaped one), but this wasn't easy to find out. In fact, I looked through the documentation distributed with it a few times, and it definitely wasn't there. (I suppose they think it's enough if the Windows driver they include on the cd knows about it.) The only place this number is written are the advertising documents which lists all properties of the monitor – I had these because I've chosen the type of monitor to buy from them.
Also note that to get a good image on a TFT monitor, you may have to press the AUTO button of the monitor. I've found that this is only neccessary when I use a certain video mode the first time with the monitor, but pressing again can never hurt. Without using this button, the image can appear sort of unfocused, or some sides of the image can be invisible.
So, I use 1280x1024 with a 17" monitor and it is very comfortable. The distance to my eyes is usually between 60 cm and 90 cm. Note that there are a few other factors that can affect the comfortability a great deal, like the tilt angle of the monitor; how high you put it (relative to where your head is), the brightness, contrast, and other controlls; and most importantly the lighting conditions of the room (the room should be lit well but you shouldn't see reflections of the lamps or the sun on the monitor). I have strong myopia which is probably why I'm more sensitive to these conditions than most others. – B jonas 13:44, 20 December 2005 (UTC)

water and acetone[edit]

can you tell me the method used to separate a mixture of 2 miscible liquids, water and propanone (acetone). The boiling point of propanone being 56 degrees celcius.

Thank you.

Repairing a Galileo Thermometer[edit]

I have broken my Galileo Thermometer but still have the glass spheres. I have tried just putting the spheres in a glass of water but they all just float at the top of the glass, even if i change the temperature of the water. Can anyone tell me what i should use instead of ordinary water and if the glass container should be sealed? Thanks David Spooner.

Per Galileo thermometer the liquid was probably not water, but an inert hydrocarbon. Perhaps mineral oil? You might try to find and contact a manufacturer and ask what they use. -- Rick Block (talk) 18:48, 17 December 2005 (UTC)

Speach recognition[edit]

I would like to open a door latching device by using speach recognition. Any ideas how i can achieve this?--172.201.249.205

I have actually built one before - albeit a very crude one. Take a recording of your voice, find the Fourier transform of it, and figure out all the unique characteristics of your voice. Then, buy a programmable digital signal processing unit, program it, and attach an output to the door. Takes about 3-4 months to figure out everything if you do this by yourself. --HappyCamper 19:04, 17 December 2005 (UTC)

Hypothetical Situation[edit]

Suppose there is a spacecraft traveling in space at near the speed of light. On it a person is traveling toward the direction that the spacecraft is moving in. If the combined speed of the person traveling relative to the spacecraft, and the actual speed of the spacecraft is greater then the speed of light, what would happen?

I'm no expert, but I would guess that all that would happen is that the collision would be equal to the collision of an object travelling at the combined speed of the two spacecraft and a solid object. --Think Fast 18:58, 17 December 2005 (UTC)
Speeds don't add that way. If the spaceship is moving at speed A relative to Earth, and the person is moving at speed B relative to the spaceship in the same direction, then the person is not moving at speed A + B relative to the Earth. The person is moving at speed {A + B}\over{1 + AB/c^2} where c is the speed of light. If one spaceship is moving at c/2 away from the Earth in one direction, and another is moving at c/2 in the opposite direction, then the speed of the two ships relative to each other is 4c/5, not c. —Keenan Pepper 19:20, 17 December 2005 (UTC)
See Special relativity#Addition of velocities. —Keenan Pepper 19:21, 17 December 2005 (UTC)
Plus the mass of the person would be so great the person would no longer be a person and the spacecraft would have been long since crushed. Hypothetically. Halcatalyst 05:30, 19 December 2005 (UTC)
Um, no? That contradicts the basic principle of relativity. You wouldn't notice anything different inside the spacecraft, no matter how fast it was moving. —Keenan Pepper 23:44, 19 December 2005 (UTC)
In human terms, I don't think there would be any "You" in a spacecraft moving near the speed of light. If there had been one when the spacecraft started off, s/he would have suffered the physical effects predicted by relativity theory, which as I recall would include fatal compression on the axis of the direction of travel. But I yield to those who know more than I (a lot of people!). BTW, I was trying to be funny above by injecting a practical objection into a theoretical discussion. Halcatalyst 01:32, 20 December 2005 (UTC)
I think, actually, that the force you would experience on your body would only be as a result of accelaration, not velocity. If you tried to quickly get to the speed of light, you might crush yourself, but if you're in a closed ship and not subject to air drag, I should think that no matter your velocity, you would be fine. It's just a matter of accelerating at a safe pace. --ParkerHiggins | Talk 01:53, 20 December 2005 (UTC)
Exactly. You would not be crushed or feel anything different in a ship going near the speed of light, because the basic principle of relativity is that you can't tell how fast you're going. —Keenan Pepper 06:05, 20 December 2005 (UTC)

Ideal and perfect gasses[edit]

Is it possible to have a gas with 50% bosons, and 50% fermions, where Fermi-Dirac and Bose-Einstein statistics are simultaneously observed? --HappyCamper 19:08, 17 December 2005 (UTC)

This would only be of observable magnitude with Helium, where Helium-3 (a rare isotope) is effectivly a fermion (as the nucelus has a odd number of fermions), and helium-4 (the common isotope) is effectivly a boson. This is, indeed observable, and is what lead to the discovery of He-3. It's noticable as a difference in boiling points. Something's tugging at my breain about miscability too, but I can't rightly recall. Syntax 03:03, 20 December 2005 (UTC)

Axions[edit]

Does the axion have a superpartner or a sparticle? If so what would it be called? The axino? --exomnium

Well, if supersymmetry and axions both exist, it would have to. There seem to be a few theory papers on this [40] [41], and it does look like it's called the axino, yes. -- SCZenz 22:30, 17 December 2005 (UTC)

Gotta go![edit]

How/why does the sound of running water encourage the urge to urinate? --hydnjo talk 20:01, 17 December 2005 (UTC)

i guess it has to do with conditioned stimulous and response, like in pavlov's experiment's.
like , when you urinate, you hear the sound, so you asociate both, and then, when you only hear the water, you asociate it again and the physiological response is triggered.
ps. sorry for my spelling, english is not my 1st language.
Sounds reasonable, thank you. --hydnjo talk 01:25, 18 December 2005 (UTC)

Why does dipping a sleeper's hand in warm water cause them to urinate? User:Zoe|(talk) 02:23, 18 December 2005 (UTC)

Maybe related to the urge to piss in a swimming pool? (Although that doesn't answer the question.) DirkvdM 09:05, 18 December 2005 (UTC)
Perhaps they think they're wetting the bed? Have you tried this with a representative sample of your sleeping partners, or is it just hearsay? --Shantavira 09:08, 18 December 2005 (UTC)
The urban legend in the US (re: hand in warm water) is that it makes the person talk in their sleep thus revealing some secrets.  ;-) --hydnjo talk 12:50, 18 December 2005 (UTC)
No, I've never tried it, myself.  :) It's something you see all the time in movies and TV shows where teenaged boys are congregated together in sleeping arrangements -- summer camp, school dormitories, etc. User:Zoe|(talk) 00:02, 19 December 2005 (UTC)

That person will feel very relaxed and so the urge to urinate comes. 165.21.83.230Naruto90

I think the theory on the hand in warm water is that it causes the person to think they are back in the womb, where they urinated freely into the amniotic fluid. StuRat 13:04, 22 December 2005 (UTC)

Tryptophan[edit]

How and when was tryptophan discovered? Who discovered it? Thanks. --69.165.33.225 20:42, 17 December 2005 (UTC)

Did you consider doing your own research before posting the question here? I just googled tryptophan and discovered and the answer is in the top ten. may be you could update the wikipedia entry with that info while you are at it? David D. (Talk) 20:48, 17 December 2005 (UTC)

Questions[edit]

  • 1) In very cold regions, how to very small rodents survive the winter? Do they group together and hibernate? The page on Mice is lacking quite a bit of information.
  • 2a) What is heat? Why do particles move faster or slower depending on heat? Why do photons emit heat on impact with other particles? Why does mass shrink or expand depending on heat? (On an atomic level, what is happening when heat is flowing into the system to cause these things to happen?)
  • 2b) Since heat is energy, why must energy be expended to cool matter, as opposed to removing energy from the matter? I'm sure that other people have thought of this before -- what is it called? --Demonesque 20:50, 17 December 2005 (UTC)

1) No idea, but I guess they hide in burrows, which keeps them warm and safe enough for hibernation.

  • It's hard for rodents and other small mammals to survive in very cold (polar) regions because their bodies dissipate too much heat. Larger animals have an advantage and that's why they're there and the rodents aren't. Natural selection. The permafrost is too close to the surface for burrows. Halcatalyst 05:23, 19 December 2005 (UTC)
There are plenty of arctic rodents, mostly lemmings and various voles. They survive the winter by tunnelling through the snow cover at ground level; the thick layer of snow protects them from the extreme cold (snow is a very good insulator). The results of the tunnelling are often very conspicuous when the snow thaws in spring, with the tunnels visible from the vegetation having been eaten away - MPF 23:54, 19 December 2005 (UTC)

2a) Heat is essentially just kinetic energy. Particles moving faster or slower isn't an effect of heat - that's what heat is. This also explains matter's expansion. Photons cause heat because radiation contains energy, and that energy has to go somewhere.

2b) What do you mean by 'energy expended'? After all, you can't use up energy. You can't create or destroy it. The concept that is instead important here is entropy. In particularly, the famous second law of thermodynamics, which states that in general, the entropy of a closed system increases. Entropy is in many ways a measure of how close the system is to equilibrium, so if you want to decrease entropy locally by moving a system out of balance - e.g. making one part cooler than another, you have to increase entropy elsewhere. (This is also why there it's comparatively easy to cool down an object that is hot relative to its surroundings.--Fangz 22:28, 17 December 2005 (UTC)

Who said it did? I didn't say question one and two were related. Anyway, thanks for the answers. Still not sure about a lot of it, though. I am familiar with the conservation of energy. What I mean is what is happening with heat that particles become "Excited." Why does it expand? Most importantly, though, I'll rephrase my last question. Why does a refrigerator have to be plugged into a wall? Heat is energy, so why must more energy be used in some form to cool the area inside of the 'fridge? Electricity or flame must be used to cool things. This seems counter-intuitive, as the air already has energy in it. Why aren't we working on a way to tap into that energy? If we are, what is it called? --Demonesque 23:34, 17 December 2005 (UTC)

Gases expand when heated because the excitation of the molecules "pushes" other molecules away. Imagine a group of close packed people, if they start suddenly moving from side to side in a quick manner, the the spaces between the people will increase, I hope that makes sense. As to why we need power to run a fridge, this is because a fridge makes use of a heat pump to cool the air inside it. This means what it is actually doing is taking heat from inside the fridge and putting it outside, thus cooling the air inside. To do this requires a compressor, which needs energy to run. - Akamad 23:54, 17 December 2005 (UTC)
To expand on what I wrote. In a fridge, we are moving heat from a low temperature area to a high temperature area, since the air inside is cooler than the air outside. This will always require an energy input. Since the natural thermodynamic order of things is for heat to travel from high to low temperatures. As to why we can't use the energy in the air in the fridge: there certainly is energy there (since it is above absolute zero). However, to make use of that energy, we require an even colder reservoir for which the heat in the fridge would want to flow into. Have a look at the Carnot efficiency article. - Akamad 00:07, 18 December 2005 (UTC)

Thank you for your answers and your time. I guess I'm not articulate enough to ask what I want to ask here. I know how refrigerators work and that molecules become "excited." I just don't know WHY they become excited. Maybe no one does?

There are some very smart people here at Wikipedia. There are also some very articulate people here. You need combination of people who know the answer to the question, can explain it well, and happen to see the question at this place.
There's a lot of stuff we are able to observe happening in nature. Some can be explained as a general rule "That's how a class of objects function under those conditions." which may or may not be an acceptable answer to "Why?"

User:AlMac|(talk) 08:09, 20 December 2005 (UTC)

To explain why the energy in heat can't be used unless there is a temperature differential, let's look at a potential energy analogy. If you had a weight at the top of a 1000 meter cliff, you could push it over with a rope attached, and use the pull on the rope to power a dynamo during the fall, to get some electricity. Now, if the weight is still at an elevation of 1000 meters, but the ground is uniformally 1000 meters above sea level, with no cliffs, there is no way to turn this weight into energy, even though it still has the same amount of potential energy as in the first example. You could move the weight to a place where there is an elevation difference, but you would likely use more energy moving it there than you would get back, unless a cliff was quite close. Similarly, you need a steep temperature differential where the two temperature regions are quite close to each other to extract more energy than is used up. StuRat 09:45, 22 December 2005 (UTC)

Paranormal[edit]

Do any of you know if the 'paranormal phenomena' issue has been settled? I mean, has anyone proven them to exist or not? The reason I ask is that there are a lot of companys and individuals out there that make a buisness out of this. They are all seem to be doing good buisness, so I wonder if there's any truth to these things. (unsigned by User:201.230.73.118 )

It is just that people like to believe in these things. there is no proof other wise James Randi's prize would have been awarded. David D. (Talk) 21:57, 17 December 2005 (UTC)
Hard question to answer. Who "proves" these things? Who "proves" that faith in God is not a waste of time, or is? "Paranormal" covers a lot of ground, and includes phenomena, or alleged phenomena, that science cannot explain. Science has dismissed a lot of so-called evidence as flawed, hence does not admit that such phenomena have occurred to begin with. I think you need to examine each phenomenon individually and ask questions about it, rather than lumping all paranormal stuff into one basket and asking whether it's true or not. JackofOz 21:59, 17 December 2005 (UTC)
The question is somewhat tautological. If a paranormal event gets proven, it instantly becomes just a normal part of science. --Fangz 22:17, 17 December 2005 (UTC)
Hear hear! —Keenan Pepper 00:26, 18 December 2005 (UTC)

It is usually impossible to prove a negative, to prove that there is no such thing. I cannot disprove the existence of the tooth fairy even though I strongly suspect she doesnt exist. Clearly no one has proven that what you probably mean by "paranormal phenomena" exist. I can imagine lots of ways to prove the existence, but I confess I cannot think of a way to disprove the whole category. What do think such a proof would be like? alteripse 00:01, 18 December 2005 (UTC)

I believe that in order to call something a theory it has to make predictions. So 'if this is true, then under these conditions such and such must happen'. And if it isn't even a theory then science can't do anything with it. Also, an experiment has to be described in such a way that other scientists can repeat it completely separately. Now 'paranormal' can mean loads of things, but let's take a psychic who conjures up spirits or whatever. Then scientists at the other end of the globe have to be able to do exactly the same experiment. But for that they'd need the original psychic, which would mean it's not an independent experiment. DirkvdM 09:17, 18 December 2005 (UTC)
That sounds like a scientist's way of saying that this particular experiment is inherently unprovable. But at least that's not as extreme as saying that such a phenomenon does not exist because science has not given its imprimatur for it to exist. A T Mann, at p.63 of "The Divine Plot" says: "... scientists assume that 2 experiments can produce the same quantitative results, but they cannot, because the circumstances can never be exactly reproduced, nor can external influences be eliminated. The earth moves hundreds of thousands of miles through space and time every day in the movement of the solar system through time. Reproducability is a central fallacy of modern science ...". Science is one way of considering and explaining the universe. It is not the only way. Seems that paranormal stuff like ESP is regularly debunked by the Randis of the world, on the basis that nobody has proven scientifically that it is real. But maybe that's the point. Maybe it's simply outside what science can grapple with, but is nonetheless very real. By staring at the back of a stranger's head, I can make them aware that I'm looking, or at least feel uncomfortable. I have done it at various times in public transport just to prove to myself that it happens, not because I'm some sort of malicious weirdo. Science would say there is nothing connecting me with that person, but I would say that I know and the other person knows there is. Science could never prove this to the satisfaction of its internal criteria. It occurs nonetheless. JackofOz 08:56, 19 December 2005 (UTC)
Rubbish. Science doesn't make any such assertion about whether or not your 'effect' is real. Science demands that before you claim it is real, you put this ability to a rigorous test. For example, the following experiment would easily net you the 1 million dollar prize:
Get a group of students. Don't tell them why they are there. Randomly select 2 groups of around 20 each. Now, sit them in a two rooms watching a movie. Now, in one room, have an experimentalist sit behind the students, staring at the back of their heads. In another, have you staring at the back of their heads. Have them write down their feelings afterwards. If a significantly higher number record feelings of being watched, then you get the money. Otherwise, it's just aphonenia. If you demand a 1-to-1 relationship, then have them watch movies 1-by-1. If you think the process is affected by stellar position, or whatever, then do it as the times you usually use the bus. If you think the bus angle is important, have them watch movies of a bus journey, or get questionaires done after they get off buses, and compare with a control set. And so on. The fact that you have 'done it at various times' is a claim of reproducibility, and it puts you into the firing range of scientific methods.
If Mann is at all right about his assertion, then he would disprove Relativity and create a huge number of paradoxes. If an effect is that sensitive to 'external events', then science wouldn't be alone in not detecting it. After all, science is just an analytical system. If it happens often enough to be noticeable in the first place, then science will certain work with that degree of reproducibility.--Fangz 12:10, 19 December 2005 (UTC)
You said: "Science doesn't make any such assertion about whether or not your 'effect' is real. Science demands that before you claim it is real, you put this ability to a rigorous test." Doesn't the 2nd sentence negate the 1st? Isn't the 2nd sentence saying that science only accepts as real those things that have been proven to be real using scientifically rigorous tests? This supports the point I was making. I am not a critic of science, but neither do I reject paranormal claims out of hand. If some phenomenon currently considered "paranormal" were to become scientifically proven, then it would no longer be called "paranormal" and its reality would no longer be questioned. But just because science has not yet proven a particular phenomenon is real, does not necessarily mean that it is not real already. Science is not the final arbiter of reality. Hamlet had it right, I think: "There are more things between heaven and earth, Horatio, than are dreamt of in your philosophy". (Philosophy here referring to knowledge, or science) JackofOz 01:52, 20 December 2005 (UTC)
  • Part of the definition of Science is that some experiment or process can be written up in detail, then some totally independent group of people repeat the experiment and get the identical results.
  • With paranormal phenomena, it would appear that some people have some abilities, from whatever sources, perhaps genetic, such that they do something, and no matter how their actions are documented, other people who lack that genetic ability are not going to be able to duplicate the process.
    • Further, the alleged phenomena is something that cannot be explained by the people observing it. It is not that they used scientific method working with some theory and experiments to polish an understanding. Rather, something weird happens, like in a dream we see something, and we think it is just a dream fantasy, then later we see same thing happen in reality. Well was the dream some kind of clairvoyance? How can we tell when a dream fantasy is a prediction, and when just a fantasy? This sort of thing is just one person's word and interpretations, like sighting a UFO or having a religious experience, far too subjective to be called Science. User:AlMac|(talk) 08:17, 20 December 2005 (UTC)
      • There's still this hang up with what science has to say about paranormal phenomena. You're all talking as if science were the only paradigm that could ever possibly be relevant. The original question was not whether paranormal phenomena have been proven scientifically, but whether they have been proven. OK, that kind of begs the question, how is something "proven" if not using a scientific method? Fair question, and not one I can answer. Paranormal phenemona by their very nature are, or can be, extra-scientific, so we need a "bigger picture" frame of reference here. My original rhetorical comment was about faith in God and who could ever "prove" this was justified. Science could never in a billion years settle that question one way or another, but there are billions of people for whom there is no possible doubt about faith in a supreme being, and for whom no "proof" will ever be necessary. The effects of prayer and faith have been voluminously documented over many millennia. Witness the 70-odd miraculous cures with the water from the spring at the grotto of Lourdes, which have been rigorously and exhaustively documented and subjected to the most extreme scientific and medical scrutiny. Science can't explain how these cures occur, which puts them into the category of paranormal. But there's no possible doubt as to their veracity. JackofOz 11:19, 20 December 2005 (UTC)
  • Question "How is something "proven" if not using a scientific method?"
  • Answer = One way things can be "proven" outside of a scientific method, is through the court system, provided someone brings a case, and it is not thrown out by a judge.
    • All sorts of people make claims, such as commercial claims about cosmetics, faith healing, spiritualism, and all sorts of people complain that those claims are bogus. User:AlMac|(talk) 02:15, 21 December 2005 (UTC)

Court "proof" is a really low standard, as it comes down to whatever a judge and/or jury, a small number of often not-too-bright people, believe. Court verdicts are often wrong as a result. Note that the existence of God could easily be proven by a personal appearance, or even a few of the Biblical miracles, like the parting of the Red Sea on a holy man's command, would be sufficient to convince most of us. The lack of such levels of proof since the dawn of science seems mighty coincidental to me. As for sudden cures, there are many explanations:

1) Many diseases do go away, or at least go into remission, spontaneously, both for those who believe in miracles and those who don't. I used to have plantars warts (on the feet), then they went away. Had I been a religious fanatic, I could have said the chicken whose head I bit off was what cured me.

2) Many diseases are subject to the "placebo effect". Arthritis, for example, is measured primarily by the amount of pain reported. If someone thinks they are cured, either by visiting Lourdes or by biting the head off a chicken, they may convince themselves the pain level is reduced or eliminated.

3) There are also shills who are willing to pretend they were sick and then cured, either for money or just for fame.

4) Then there is just the gap in media coverage. The millions of people who visit Lourdes and don't have any "miraculous cure" rarely get much press. This makes it seem that the few who do report a cure are 100% of the people who went, because we never hear about the rest.

I believe many of the paranormal claims have been disproven. For example, the "cold reading" methods used to convince people a particular "pyschic" has a connection with the dead can be easily replicated by anyone who spends a few hours studying the technique. For example, when someone points to a part of the audience and says "I'm seeing someone over here whose name starts with a J"...the chances that one of the 100 people in that general area will have a first, middle, or last name starting with J, or have some dead relative with a first, middle, or last name that starts with J, is probably in the 99.999% range. Yet, when somebody says "that's me !" they are absolutely sure the "pyschic" has proven his "gift" and are ready to hand over their life savings to them. It's hard to believe that the dead person is only able to tell the pyschic the first letter, and not the whole name. It also seems odd that no dead person ever tells the pyschic his name starts with a rarely used letter. Dead Quincy, Xavier, and Zachary apparently lack the ability to communicate with pyschics, LOL. StuRat 09:06, 22 December 2005 (UTC)

StuRat 09:06, 22 December 2005 (UTC)

Conway's life computer[edit]

Has anyone made a computer in a Conway's life simulation?--Shanedidona 23:59, 17 December 2005 (UTC)

This reference from Conway's life:

describes how a Turing machine can be made in the "life" simulation. --JWSchmidt 00:11, 18 December 2005 (UTC)

December 18[edit]

Christmas Debts[edit]

Christmas is coming. People in the U.S. are burying themselves in debts.

http://www.nytimes.com/2005/12/11/national/11credit.html
http://www.mezomorf.com/emailed/news-15976.html
December 11, 2005
Newly Bankrupt Raking In Piles of Credit Offers
By Timothy Egan
... Ms. Fogle is broke, ... she had no sooner filed for bankruptcy, ... than [sic] she was hit with a flurry of solicitations from major banks. ... "Every day, I get at least two or three new credit card offers ... at pretty high interest rates,"
...Credit card companies have long solicited bankrupt people, on a calculated risk that income from the higher interest rates and late fees paid by those who are trying to get their credit back will outweigh the losses from those who fail to make payments altogether.

What? Is this the whole story? Where do the late fees and interests go? Do they become a part of the banker's profit immediately? Or are they used to write-off the debt as well? I think most, if not all, late fees and interests go to the banks. Am I right?

Let's say there are two banks, each lends the same money to customers at the same interest rate.

  • Bank A: Reliable customers. They pay back the debts on time. And they come back again when they need money.
  • Bank B: Unreliable customers. Most of them pay the minimum. Some pay old debts with new debts. Some go bankrupt.

Because the interest rates are the same. You can say they make roughly the same money each year if the interests directly go to the bankers. Only Bank B has a much lower turnover rate.

In theory, the bank's money comes from depositors. The depositor shall get the money back. So the bank needs to collect the profit and the seed money as well. However, ...

  • Bank A: The bank makes easy money. Its depositors are safe.
  • Bank B: The bank makes easy money. Its depositors are taking all the risks.

It seems to me in the case of Bank B, the bank takes almost all the profits and very little risk. The risk goes to the depositors. If the bank goes bankrupt in a decade, that's not today's managers' problem. They'll be retired by then. Am I right? Is my theory applicable to the fact? -- Toytoy 04:55, 18 December 2005 (UTC)

  • Bank depositors in the US aren't really under any risk. See FDIC. Night Gyr 11:31, 19 December 2005 (UTC)
This is in no way a problem limited to the banking industry. Making short-sighted decisions designed to increase quarterly profits at the expense of the long-term health of a company would seem to be in the interest of many CEOs. For example, selling off the most profitable divisions for immediate profits, leaving the company saddled with unprofitable divisions, would serve a CEO who has a bonus structure based on current profits only. The only limiting factor is that SOME shareholders do have the long-term interest of the company in mind, especially employee shareholders. If they can manage a majority, they can fire such a CEO before he does too much damage to the company. Of course, if they again offer pay based strictly on short-term performance to the next CEO, they are likely to get the same result. StuRat 08:27, 22 December 2005 (UTC)

what is this brain-related(?) phenomenon called?[edit]

So a couple nights ago, after playing Wave Race 64 for what must have been 5 or 6 hours almost nonstop, I went to bed. However, the patterns of the waves in that game, rapidly undulating up and down, would keep "playing" in my mind, like an uncontrollable looping video, making it hard to sleep.

First off, does this phenomenon have a name? Second, is it related at all to how when you hear a catchy tune, for whatever reason it keeps playing in your mind even when you try to think about something else (damn you, Pink Floyd!) and it effectively messes up your concentration or sleep also? --I am not good at running 07:42, 18 December 2005 (UTC)

Hypnagogia. —Keenan Pepper 08:16, 18 December 2005 (UTC)
Hypnagogia is a bit much for this, don't you think? This appears to be a common case of overstimulated nerves. It is like riding on a motorcycle all day and feeling the rumble of it all night or wearing a hat for hours and then feeling it on your head long after it has been removed. Some nerves are very sensitive to overstimulation - especially the cones in the eye. After being stimulated, they continue react when the stimulus is removed. The brain just responds to the nerves. So, after stimulating various nerves in the body all day and then removing the stimulus, the nerves continue to react and signal the brain. If you want to get really scientific about it - the nerves are actually having a negative reaction. They are sending a signal that the stimulus is not there. But, for something like motion, moving left right left feels about the same as moving right left right. --Kainaw (talk) 16:58, 18 December 2005 (UTC)
I think what you just described is an afterimage, and those don't last more than few minutes. —Keenan Pepper 19:30, 18 December 2005 (UTC)
Correct. Afterimage occurs in the optic nerves. They are easily stimulated and quickly get over it. Nerves that are harder to stimulate will have the afterimage effect much longer. --Kainaw (talk) 13:49, 19 December 2005 (UTC)
Somewhat related, the McCollough effect (external link), which I find mildly freaky. A simple pattern which affects your visual system for hours or days! Maybe there's a similar visual memory regarding motion, beyond the usual "waterfall illusion"-type motion aftereffects. Femto 14:40, 19 December 2005 (UTC)
This is blowing my mind! It lasts so much longer than an afterimage! You turn your head and the colors magically switch back and forth! —Keenan Pepper 06:21, 20 December 2005 (UTC)
Told you it's freaky. =) Femto 12:17, 20 December 2005 (UTC)
I've noticed that some time after cross country skiing, my walking motion is more like skiing. It takes a while to "switch back" to normal walking. StuRat 08:07, 22 December 2005 (UTC)

Can a Boeing 777 use a ram air turbine?[edit]

Can a Boeing 777 be built/use/retrofitted with a ram air turbine? I read the article on the 777 and it did not state whether or not the 777 can use the RAT. --Blue387 07:52, 18 December 2005 (UTC)

  • The answer appears to be yes: [42]. --24.31.29.171 08:39, 18 December 2005 (UTC)

Coffee - water temperature[edit]

Coffee#Brewing says that coffee should ideally be made with water at 93 C. I use the first method under 'boiling'; I put the ground coffee in a cup and pour boiling water on it. Now boiling water is 100 C. But I assume that during the pouring the water will cool down fast. But it would have to 'loose 8 C' over a distance of about 10 cm. Of course this is more complicated, because the cup will cool it down even faster, but then the ground coffee will have already been in contact with hotter water and I don't know how how bad that is. But could someone with a good thermometer test this? Pour boiling water and measure the temperature at various distances? And, alternatively, pour the water in a cup and measure the change in temperature. Of course this would require a very fast-acting thermometer, and preferably an electronic one. But I believe those exist (well, I know they do, but are they fast enough?). DirkvdM 09:35, 18 December 2005 (UTC)

This does not a question make. Seriously, it's difficult to figure out what your asking. Are you worried that coffee prepared in a cup will cool faster than in a pot? In any event it is not a concern, I know that pouring water in a cup to prepare something, say ramen noodles doesn't cool until some time after they are ingested.--Ridge Racer 15:06, 18 December 2005 (UTC)
I thought the question was quite clear. I want to know at what temperature the water is when it hits the ground coffee, because ideally it should be 93 C. How to measure that is the problem. Especially if you don't have the right thermometer, so that's why I made that bold. Just a simple experiment for someone with the right equipment. DirkvdM 08:11, 19 December 2005 (UTC)

The water should not be at 93 degrees. Water that hot will burn the coffee. That is why professional baristas use thermometers when thay make coffee. Especially, if you are making a latte, cappucino, or flat white, the milk should not be heated above 65 to 70 degrees before it is poured into the espresso. Milk protein scalds at around 70 degrees. Many people like their coffee to be very hot. In that case the cup can be preheated with 90 degree (or so) water. A digital thermometer is pretty inexpensive, about $15, and will give you a nearly instant read ---Rupee

I just hoped domeone would have such a thermometer ready. It would have to be very instant, though, giving the right temperature in a fraction of a second. But are you saying the coffee article is wrong? At what temperature should the water be then? And does it depend on the roast and grainsize? Never mind the milk because I drink my coffee straight. DirkvdM 13:26, 23 December 2005 (UTC)

premature grey hair[edit]

What are the reasons for premature grey hair ? What is the medical solution for it ? 59.94.96.77 09:43, 18 December 2005 (UTC)Tina

1) Genetics. 2) Hair dye, if you want to disguise it. Ever wondered why Chinese people don't go grey? Expert use of hair dye. See this BBC article.--Robert Merkel 11:14, 18 December 2005 (UTC)

See hair color for some details. alteripse 14:26, 18 December 2005 (UTC)

I would argue with the term "premature greying". We have this concept that people, especially women, don't get grey hair until they are elderly. This misconception is reinforced by the media and the extensive use of hair dye, when, in reality, middle age is when most people start to grey, and many start earlier on. I had my first grey hair at 18 (right after I started drinking cofee, I wonder if there is a relationship). StuRat 13:09, 22 December 2005 (UTC)

the speed of light[edit]

what is the speed of light

Why, it's how fast light moves!
Just kidding. It's all there at Speed of light --ParkerHiggins 10:15, 18 December 2005 (UTC)

CPU clock rate and performance[edit]

1. What is good (accurate, easily obtainable) indicator of processor performance (speed), today?

Until some time ago, we used CPU clock rate ("megahertz") to gauge processor performance (speed), and it seemed pretty accurate too. However, I think gauging CPU performance solely based on its clock doesn't seem to be relevant today, as most processor manufacturers starting to remove CPU clock (at least from product names), and I heard many benchmarks resulting in CPU with lower clock rate outperforming CPU with higher clock rate.

Read benchmark (computing). There's no way to give a specific answer to your question without knowing what kind of work you wish to do with your processor. --Robert Merkel 11:10, 18 December 2005 (UTC)
A clock tick tells the computer to start changing to the next stable state. Put more clearly, one instruction is performed per clock cycle. But that leaves the question how big an instruction is. Because different architectures (with different size instructions) started to compete on the market, the clock rate was no longer a good indication (walking for ten minutes doesn't get you further than running for five minutes, so to say). Anyway, the processor speed (however measured) is overrated. It's a good rough indication, but other parts of the computer can matter a lot too, depending on what kind of work you want it to do. Fort example, if you need to do a lot of graphical work (like movie editing) then a graphical card that takes some load off the CPU's back will help more than a faster CPU (being a fast runner doesn't help a lot if you need to cross water (unless you're a jezus christ lizard - or indeed the guy himself :) )). But there are many more aspects, indeed too many to mention here. DirkvdM 08:49, 19 December 2005 (UTC)

2. Why the growth of CPU clock rate is not as fast as a few years ago? Are we approaching some kind of limit? 61.94.149.220 10:20, 18 December 2005 (UTC)

A combination of physics and economics; notably, as I understand it the speed of light is becoming an issue. Say your processor is running at 3.2 GHz. That means one cycle takes 3.12500 \times 10^{-10} seconds. Light (and no signal can be transmitted across the chip faster than light, generally electric currents are significantly slower) travels at approximately 3 \times 10^8 metres per second. That means that in one clock cycle, light can only travel a bit under 10 centimetres, and electric currents a bit less than that again.
But as processes continue to shrink, you've got all that extra space on your CPU die; how do you take advantage of it? Well, what AMD and Intel have done is whack a second CPU inside the one physical chip; it's the easiest way to take advantage of the space, and seems to improve performance a lot more than using the space for more cache would. --Robert Merkel 11:10, 18 December 2005 (UTC)
So in order to increase speed you need to make the CPU smaller, but now the limits of the present technology (the materials used) are approaching the limits (although that has been said before and workarounds like Robert mentions have circumvented the problem). The size of the conduits are approaching molecular levels. So different materials and signal carriers (like light) are being researched. I can't find an article on this, though. Surely there must be one (a technical subject (computer related even) that is not covered by Wikipedia? Impossible! Right?). DirkvdM 08:49, 19 December 2005 (UTC)
Optical computer. Da daaah! Proto t c 10:48, 20 December 2005 (UTC)
As well, CPU's are burning up as all those moving electrons get packed into a small space. Intel is dying with this right now. AMD and Sun are trying other methods to increase memory throughput. --Zeizmic 15:23, 21 December 2005 (UTC)

computer hard disk[edit]

if i connected two hard disk to my system them onlu one har disk is activated why this

then same thing two hard disk and my operating system in second hard disk at that time from which hard disk system gets boooting email removed

What operating system do you use?--Ridge Racer 15:08, 18 December 2005 (UTC)
Did you check to make sure the jumper pins are set correctly? Proper master/slave settings are necessary - I think. --HappyCamper 15:09, 18 December 2005 (UTC)
Most PCs have two IDE connectors. The Operating system usually looks for the first harddrive on the first IDE connector. What is not explained in the question is: Are they IDE drives? Are they using the same cable? Have the jumpers for Master/Slave/CS been changed? Is the new harddrive formatted? If so, is it a format readable by the OS?
Usually, just setting all drives to CS (cable-select) will fix the problems. --Kainaw (talk) 16:50, 18 December 2005 (UTC)

Chemistry Question: Chloroform-like Anesthetic?[edit]

In writing a chapter in an ongoing fantasy story, I've come across an interesting opportunity to link a present event to a future character (an alchemist, among other occupations) that will eventually make an appearance.

But in order to avoid a too-obvious deus ex machina, I'd prefer using an actual substance that can be isolated solely through repeated distillation or other relatively simple chemical processes, which has incapacitating properties more-or-less identical to that of chloroform as it is commonly (and inaccurately) portrayed on network television shows.

Any assistance would be appreciated. --The Confessor 15:23, 18 December 2005 (UTC)

Try halothane, isoflurane, sevoflurane and desflurane, which are listed as Inhalational anaesthetics. All of them may not be produced very easily/readily, but I'm sure your character would have no trouble obtaining some.--Ridge Racer 15:42, 18 December 2005 (UTC)
Personally, I'd go for Nitrous oxide. Simpler of all the compounds. --HappyCamper 17:22, 18 December 2005 (UTC)
NOS effects are disassociative. Incapacitating, but not so as to produce unconsciousness... and thus unsuitable for this plot element. --The Confessor 17:44, 18 December 2005 (UTC)
Pretty damn close to unconsciousness, for what it's worth. But what about ether? Easy enough to make (distill ethanol and sulfuric acid). General anaesthetic. --jpgordon∇∆∇∆ 18:15, 18 December 2005 (UTC)
Does anybody else think it's a bad idea to assemble a list of easy to purify, volitile solvents, that could be used to render someone unconscious? (: Oh and ether would boil away too fast I think--Aolanonawanabe 19:42, 18 December 2005 (UTC)
You mean a list like that on wikipedia? Sounds cool to me, but reminds me of The Manual of Crime over at wikibooks, which sadly was deleted.--Ridge Racer 20:49, 18 December 2005 (UTC)
That was simply a loaded question. Realistically, any content on Wikipedia can be construed as "dangerous". The mind is abstract enough to do this if it wanted to. --HappyCamper 23:06, 18 December 2005 (UTC)
Nope, ether works just fine and in fact used to be kept in little bottles in doctors kits for the express purpose of being an easy-to-administer general anasthetic (just put it on a rag and inhale it). -User:Lommer | talk 23:51, 18 December 2005 (UTC)

wavelength[edit]

i would like to know what is the frequency and wavelength emitted by an ordinary tubelight or an lamp?...........

  • You should be able to derive this from the color of the bulb using this as a standard --Aolanonawanabe 18:35, 18 December 2005 (UTC)
    • Tube lights typically have very narrow spectral bands rather than a gradation of light throughout all frequencies. In other words they are not like sunlight. So the question is what is ordinary? In fact there are many different tube lights that have different light qualities. Some are more red, others more blue and others a mix of all colors, so called full spectrum. Check out this page for some typical spectra. David D. (Talk) 19:52, 18 December 2005 (UTC)
Is "tube light" British Engish for a fluorescent light ? StuRat 07:51, 22 December 2005 (UTC)

burning cd with more than 2 gb data[edit]

how to burn a cd of 700 mb with more than 1 gb to 5 gb fo data in it. i saw a cd windows 2003 pirated 10 in 1 with 4.7 gb of data in it....

The maximum raw capacity of a CD-ROM varies; some can actually store up to about 912 megabytes of data. Data compression can allow data to be "squeezed" into a smaller amount of data, and expanded to its original format when desire. However, in most cases, data distributed on CD's is already distributed in compressed form. I suspect what you actually saw was a DVD-ROM. DVD-ROM is so cheap and ubiquitous nowadays you wouldn't bother trying anything else.--Robert Merkel 21:42, 18 December 2005 (UTC)
  • For such high amounts of data, I would recommend a DVD-ROM as well. There's no way 1-5 Gb is going to fit on a regular CD-ROM. - 131.211.210.10 08:29, 19 December 2005 (UTC)
Of course, a DVD with hacked software would probably not be a DVD-RAM, but a writeable DVD, but it redirects, so above link still works. DirkvdM 08:54, 19 December 2005 (UTC)
4.7 GB is the standard capacity for a DVD, so what you probably saw was really a mislabeled DVD. Night Gyr 11:18, 19 December 2005 (UTC)

Circuitry question[edit]

I was hoping to build this circuit of an analog synth. It's very simple, I understand, but I haven't done much building in my career. I have a question with the inverter number CD40106, and it's location on the circuit. Part UI-A (which I think is two of the prongs on the 14 prong inverter) appears to have four connections to it. It looks like two go off to resistors, and one goes to a power, and the other goes to a ground. I don't know how that works, or how to wire that.

I have a picture of the part of the schematic in question, but I'm not sure if I can upload it for copyright reasons. I'd be perfectly happy to provide any more information if it would help! --ParkerHiggins | Talk 22:25, 18 December 2005 (UTC)

That is the standard way to draw the power connections to an IC that contains multiple logic gates. U1 is a hex inverter, and all six inverters in the package share the same two power pins on the IC - pins 7 and 14. (Note: 'pins', not 'prongs'.) To save space, we always draw five of the inverters without any power connections, and one with them. In this case, they have drawn the power pins attached to the inverter with its input on pin 1 and its output on pin 2. All you have to do is wire up pin 14 to the positive supply and pin 7 to the ground, and all six inverters will then work. --Heron 23:01, 18 December 2005 (UTC)
Good answer Heron, looks like I shouldn't have taken so long to answer the question after starting the edit. A 23:13, 18 December 2005 (UTC)
You are right, U1-A is part of the same chip as U1-B and U1-C. The extra conections you see in U1-A that are absent from the others are for power (pin 14) and ground (pin 7). Common convention states that you should include these pins on one of the device elements, U1-A in this example, as they do need to be connected for the chip to work, but not all of them. A 23:11, 18 December 2005 (UTC)
Oh man, you guys are lifesavers! Just to clarify, there is no distinction as to which two pins are 7 and 14, right? I mean, they're on one end, but doesn it matter which end, or is there any way for me to tell which end? Thanks! --ParkerHiggins | Talk 23:56, 18 December 2005 (UTC)
To rephrase that question, is there a standard system of pin numbering? For example, it seems reasonable to me that U1-A, for example, would refer to a set of pins opposite each other, as would the power pins, 7 and 14. Shouldn't the connections from U1-A be labeled 1 and 8, then, not 1 and 2? Also, is there any distinction between pins 1 and 8 and pins 7 and 14? If I flip the inverter over, there's no telling which is which! If it would help answer this question (I know I'm throwing a lot of arbitrary numbers around) I can photograph the component itself. --ParkerHiggins | Talk 07:42, 19 December 2005 (UTC)
If it's the usual sort of DIP package, one end will be marked with a U-shaped notch or depression. Since it's got 14 pins, holding the notch uppermost and looking at the labelled side, the pin numbers will run 1-7 down the left side, then 8-14 up the right side. Thus the power pins will be the bottom-left and top-right pins. If there's no notch, usually pin 1 is marked with a dot.
For example, our picture at Image:DIL14 IC HCF4093.jpg is a 14-pin DIP. You can see the notch at the top left. The pins we can see will number 1 to 7 from the left to the right. The pins we can't see from this angle with run 8 to 14 from the right to the left. --Bob Mellish 15:33, 19 December 2005 (UTC)
Aha! So that's the page I was looking for. It's actually, I think, the same DIP in that picture. Or at least very similar. Thank you! --ParkerHiggins | Talk 15:35, 19 December 2005 (UTC)
If you are ever in doubt about the pin numbering of a common device like a 40106, just go to the website of a mail order electronic components company like http://www.maplin.co.uk. They have a page of information called a data sheet on every device they sell, including the 40106 (PDF here), that includes a picture of the gates with pin numbers. Happy constructing! (And no, I don't work for Maplin.) --Heron 20:42, 19 December 2005 (UTC)

December 19[edit]

The See Clearly Method[edit]

I was wondering if anyone could answer the question of wheather the "See Clearly Method" works. The "See Clearly Method" has been advertised as being able to correct a person's vision naturally without the use of a new perscription for ones eyeware. I was also wondering how it actually works? If it does what are its limits, etc?

Pure bullshit. Anyone can become a doctor and advertise as such these days. Generally speaking it lists treatment as eye exercise, diet/nutrition, and a low stress lifestyle. This might help slightly blurry vision if you have malnutrition or stress, but trust me, if your eyesight requires prescription glasses, you can't fix them for $9.95. Also, quoted from the site, * This self-assessment should not be used as a substitute for the medical diagnosis and treatment of your vision, nor should the See Clearly Method be a substitute for diagnosis or treatment by an optometrist or ophthalmologist. Before using the See Clearly Method, you should consult with an optometrist or ophthalmologist to determine if any eye disease or other condition requiring specialized treatment is present.--Ridge Racer 03:05, 19 December 2005 (UTC)
Yes, but they are counting on the fact that their potential customers can't read that fine print. LOL. StuRat 05:20, 22 December 2005 (UTC)
Snake oil, anyone? David D. (Talk) 05:34, 19 December 2005 (UTC)
We have articles on this sort of thing, but they're not very prominent. Bates Method is similar pseudoscience for natural eye correction. Night Gyr 05:55, 19 December 2005 (UTC)
Yes, it's pure quackery. Neutralitytalk 06:18, 19 December 2005 (UTC)
  • Perhaps it could help you see clearer when the correction needed is very little (less than minus 1). Anything higher is not going to be correctable with mere excercize. Making your eyes strain to see properly is more likely to tire them than anything else. - 131.211.210.10 08:33, 19 December 2005 (UTC)

Ciliary muscles[edit]

Are the ciliary muscles the only smooth muscles that can be controlled voluntarily? —Keenan Pepper 03:50, 19 December 2005 (UTC)

I don't think one can voluntarily dilate their own pupils, which is what you seem to be suggesting. Nrets 16:58, 19 December 2005 (UTC)

The ciliary muscles do not dilate the pupils, they change the shape of the lens to focus on near or distant objects. (The other muscles are called, logically enough, iris dilator muscles.) I can voluntarily make my eyes go in and out of focus, which seems like I'm voluntarily contracting and relaxing my ciliary muscles, but I could be wrong. —Keenan Pepper 21:14, 19 December 2005 (UTC)

Six Kingdoms and Microbes[edit]

I've heard that there are six kingoms of living things in the world: animals, plants, fungi, protists,eubacteria and archaebacteria.But what about microbes?I've about heard that apart from animals and plants the other type of living thing that exists is microbes.So why haven't biologists classified microbes as a single group of living things?

Believe it or not there is more genetic diversity among microbes than there is among plants and animals. The eubacteria and archaebacteria are the current kingdoms that describe prokaryotic microbes. I guess protists could be described as microbes (assuminjg you are using the general definition of small) but they are definitely eucaryotes and so are not grouped with the prokaryotes. Not all fungi are microbes. Some fungi are the largest organisms on earth. You can't see them as they are in the soil but they can be as large as 15km2 in area. David D. (Talk) 04:24, 19 December 2005 (UTC)
Single-celled plants and animals might also be called "microbes", if going strictly by size. StuRat 05:17, 22 December 2005 (UTC)
Here is another link that might be useful: Kingdom (biology). David D. (Talk) 04:31, 19 December 2005 (UTC)
In other words, the term microbe is about size, it is not a taxonomy classification. And the number of kingdoms is also reason for dispute. A logical ordering wqould seem animals, plants, fungi and bacteria. But that's anthropomorphic. Along the lines of what David said, there is more variation among bacteria than among the other classes, so those should be grouped together, as Woese does, who introduces a third 'class', Archaea, based not on looks but on genetics (which makes more sense). Archae would by looks be classified as bacteria, so basically there's bacteria, bacteria and Eukaryotes, which include animals. We animals are just a speck in the variation of life. Actually, there's even dispute about the classification into Kingdoms, with Domains being an alternative higher 'order' (hard to find the right word here because 'order' and 'class' are themselves terms in the classification). DirkvdM 09:24, 19 December 2005 (UTC)

Japanese fonts[edit]

Hi, this is a question related to Wikipedia. I recently re-installed windows and now I seem to have lost my japanese fonts. I can't edit japanese content anymore because everything shows up as question marks in Firefox and IE. Where do I download japanese fonts for windows so I can edit again? I've had no luck googling for the answer. Thanks --Quasipalm 05:30, 19 December 2005 (UTC)

In Firefox, click View --> Character Encoding, and see if you can pick one of the goodies there that works... --HappyCamper 05:44, 19 December 2005 (UTC)
Thanks, but I checked that early on and Firefox recognizes the page as Japanese or UTF-8 as the case may be, but it simply doesn't show correctly. This lead me to believe that the fonts on my system don't have glyphs for Japanese, but I'm clueless how to find fonts that do that I can install. Thanks for the follow up though, I should have added that to begin with. --Quasipalm 17:16, 19 December 2005 (UTC)
On a related note, doesn't wikipedia have a page where you could test this stuff out and then gave instructions on how to get the fonts? I could swear I came across something like that while reading the Unicode article.--Ridge Racer 06:16, 19 December 2005 (UTC)
It's the sandbox. Max 216.209.153.57 15:05, 19 December 2005 (UTC)
If you go to the Microsoft website, you can download Japanese at [43]. That's what I did, but it doesn't work with all versions of Windows, and you might need Office XP. smurrayinchester(User), (Ho Ho Ho!) 18:58, 19 December 2005 (UTC)
I think people are often a little too keen to download things which they already have. Windows 2000 and XP come with all the Japanese fonts and stuff you need, you just have to install them. This is an indirect process: basically you tell Windows you want to support a language (and this involves more than installing the font) and Windows will do what is required (have the Windows CD handy). Start at the Regional/International control panel. Notinasnaid 18:04, 22 December 2005 (UTC)

plane of voltage generation in piezoelectric crystals.[edit]

sir, Is the plane of application of stress and plane of voltage generation same in the case of piezoelecric crystals(both 2d and 3d)??.if no how do they vary? 07:48, 19 December 2005 (UTC)

Piezoelectricity does give me a clear answer. It seems to be normal to the stress vector, and the piezoelectric vector, I imagine this has to do with symmetry. Dominick (TALK) 18:10, 19 December 2005 (UTC)

Globalization[edit]

what will be the necessary steps about Globalization for the undeveloped country ?
<Email removed - please see instructions at the top of the page.>

I'm afraid I don't understand your question linguistically, but you may find the following articles useful: Globalization, Anti-globalization, and Economic development. Happy reading! — QuantumEleven | (talk) 10:35, 19 December 2005 (UTC)

I'll hazard a take at this question. In order for an undeveloped country to become successful in the global economy several things must happen:

External factors

  • Developed nations must be willing to trade with your country on a level playing field. This includes no tariffs, quotas, or other trade restrictions, and no subsidies for competing products from their end. Current WTO trade negotiations are moving in this direction, but we are not there yet.

Internal factors

  • Transportation infrastructure; such as roads, railroads, seaports, and airports; must be developed.
  • Communications infrastructure; such as telephone lines, cell phone towers, satellite phone access, and internet access; must be developed.
  • Energy infrastructure; such as electricity, natural gas, and gasoline; must be made available.
  • Other infrastructure; such as drinkable water, sewage and garbage disposal; is also needed.
  • Educated workers are needed which are willing to work and reliable. Typically, in the early stages it is necessary to import large numbers of highly educated workers. Later, as more natives become well educated in production techniques, they can take over many of the technical jobs.
  • Modern housing is needed, with heat, air conditioning, indoor plumbing, etc.
  • Security is needed. That is, workers and executives must feel reasonably safe from war, ethnic conflicts, terrorism, and hostage taking attempts. Ideally, these things can be eliminated entirely. If that is not possible nationwide, creation of a "safe zone" with heavy security, may be the only immediate solution.
  • Stable government is needed. In particular, a peaceful method of succession is needed for transitions in government. The threat of coups or other political instability will drive off investments.
  • Honest government officials are needed. Those which require bribes to do their jobs scare off investment, not so much due to the money itself, but rather due to the unpredictability of not knowing what level of bribes are required by each official.
  • Honest government leaders are needed. Those which steal all the nation's resources leave little for infrastructure development. Democracy is typically necessary, but not sufficient, to get honest leaders. Voters must also put a higher priority on honesty than other factors, such as whether a candidate is of the same religion, ethnicity, or tribe as the voter.

StuRat 05:01, 22 December 2005 (UTC)

Synthesis of a sine wave from square waves[edit]

You've got that right. From square waves, not the common and easy other way around. I don't have a particular reason to want this right now, but looking at the samples of a sine wave on a sound file I got... well, inspired.

Anyway, after thinking about it a little I found out that this sum, \sum_{k=0}^\infty -\frac{sig(\sin x(2k+1))}{2k+1} \mbox{ where } sig(x) = \frac{x}{|x|} (the fundamental is positive, though), leads to a somewhat "good" approximation of it:

Sine from square waves.gif

As you can see, the values tend to expand indefinitely on the zero crossings of the 3rd harmonic, and the overall shape is not smooth but it is stable. Now, my questions:

  1. Is this the best method to approximate the sine curve?
  2. What could I use here to at least stop the indefinite growth at the zero crossings?
  3. If this was a signal, what could be used to smooth it? (a filter of some sort, perhaps?)
  4. Incidentally, how those electronic oscillators generate sine waves?

Anyway, any help and light on the subject would be nice. Thanks! :D ☢ Ҡieff 08:49, 19 December 2005 (UTC)

I'm no expert on the subject (or any subject for that matter), but as a square wave can be made by adding up the odd numbered harmonics of a tone, the opposite could be done by substracting them. Right? Maybe that's what Subtractive synthesis does. DirkvdM 09:47, 19 December 2005 (UTC)
Not really. Check square wave. The result of the additive synthesis using sine waves is imperfect. All these are really approximations. Also, the above sine approach was done by continually subtracting square waves of the fundamental wave. ☢ Ҡieff 10:42, 19 December 2005 (UTC)
No, this is not the best basis for approximating sine curves. the best basis is obviously the sine curves themselves, wherein every Fourier series has only 1 term. Any basis that is "close" to sines will do better than square waves. I'll wager you'd do quite well with sn x for small elliptic modulus.
Well, I meant with square waves, really. If I could afford anything else for the experiment involved here this wouldn't be a challenge, would it? Also, elliptic functions are far mor complex than a square wave function. ☢ Ҡieff 11:42, 19 December 2005 (UTC)
Oh, I see. Well in general, Fourier series are unique. So if you've found the right Fourier series for sine in terms of square waves (I haven't checked it), then not only is it the "best" approximation; it's the only approximation. As far as elliptic functions being complex... well I just thought you were looking for any mathematical functions that could approximate sine curves, and from a mathematical standpoint, the elliptic functions are far more simple than square waves, among periodic functions. But I guess I misunderstood the question.
Exactly. By the way, Fourier series pretty much apply only for sine waves, no? ☢ Ҡieff 14:43, 19 December 2005 (UTC)
How can you ask that, after having just done a Fourier series with square waves? No, you can do Fourier analysis in any orthonormal basis. -lethe talk 16:13, 21 December 2005 (UTC)
I've just never seen the name Fourier being used to call anything else involving something that isn't sines. ☢ Ҡieff 21:41, 21 December 2005 (UTC)
The growth that you see at the zeros should probably not be unbounded; it should stop at some finite limit. This is known as the Gibbs phenomenon, and is well known when approximating jump discontinuities with smooth functions. I've never seen it mentioned when it comes to approximating smooth functions by discontinuous ones, but it doesn't surprise me at all that they exist, and I expect similar methods to fix them would work.
Good point. It never occured to me that these could be Gibbs or Gibbs-like. I'll look into it later. ☢ Ҡieff 11:42, 19 December 2005 (UTC)
Just checked. They're unbounded! :| ☢ Ҡieff 14:05, 19 December 2005 (UTC)
That's weird, I think it should be bounded. I wonder if the lack of differentiability is the cause of this. -lethe talk 16:13, 21 December 2005 (UTC)
Actually, if you look at the signal function, they shouldn't be, since \lim_{n \to 0} sig(n) = \pm1, and you're always dividing this value to the odd number of harmonic and adding that to the point near the node. I can't really explain this mathematically because I don't know the english terms, but the points near zero will always have something added/subtracted. ☢ Ҡieff 21:41, 21 December 2005 (UTC)
A low pass filter ought to do the trick, no?
Aaah! Thought it'd be able to chop those jumps. I'll have to experiment with it later. ☢ Ҡieff 14:05, 19 December 2005 (UTC)
Yep. Tried the lowpass filter with only 10 harmonics and I got an excellent approximation. :D Still, I wonder if there is a filterless method. ☢ Ҡieff 02:12, 20 December 2005 (UTC)
AC (= sine curve) currents arise naturally ought of electric generators. I'm not sure how to turn a square wave into an AC wave. You could maybe get some nice approximations by combining some filters. Maybe an electrical engineer will happen by.
Yes, AC = sine, but what about generating a sine curve from DC? I suppose you could play with some capacitors and diodes approximating a triangle wave signal, but that wouldn't be all that accurate either. ☢ Ҡieff 11:42, 19 December 2005 (UTC)
The more I think about it, the more I think you probably cannot do this with simple analog circuitry. All circuit elements I know turn DC currents into at worst exponential decays. The only way to introduce sinusoids is with other sinusoids. So I'm thinking hook the square wave into an on/off switch for a generator.
thinking even more: using resonance, you can get filters that select a narrow frequency band. Pass a square wave through that filter with the right band, and it should select only a single harmonic, which will be sinusoidal (to a great approximation).

-lethe talk 11:16, 19 December 2005 (UTC)

Anyway, thanks for the answers so far! I'm still gonna take a good look at this... ☢ Ҡieff 11:42, 19 December 2005 (UTC)
DC is turned into AC because you know exactly what youre trying to make (60hz pure sine) and the circuit is designed to pulse at a high frequency to 'build' the sine wave as it goes up and down, the current is then filtered via a coil into a near-perfect wave which then actually feeds back and modulates the PWM input to ensure the sine tracks properly at a varying load. This is 'easy' since there is a sine already present. Transistor audio amplifiers work the same way, except they use a variable input as the tracking source. Working from an unknown square wave is tough since you can't see the future to know when the pulse will end.
Easier way to do this without anything fancy. Integrate the square wave, using a wide band integrator with a low frequency dump, you will get a good triangle wave. The triangle has much lower harmonic content, every other odd harmonic with flipped phases every other odd harmonic. Synthesize a sine from that. Another approach would be to filter the tringle wave, with a low pass filter. You would be able to use a simpler LPF.Dominick (TALK) 16:17, 19 December 2005 (UTC)
Why not just use a low pass filter? That should do the trick. --HappyCamper 00:14, 20 December 2005 (UTC)


I don't know what it is, but that infinite series does not look quite right...unless....hm....... --HappyCamper 00:06, 21 December 2005 (UTC)

Contamination / Oxidize "Aluminium"[edit]

Hello my name is Keith, I'm a steel worker I have just started working with aluminium and myths are floating in the air and i'm looking for some help, I was just wondering if you were to grind on mild steel and the red hot sparks are shooting off and hitting "In Contact" the Aluminium what would happen? would it be contaminated, corroded, oxidized??? please help.

Hi Keith. I'm not an expert on this, but as I understand it the red hot sparks from a grinding wheel are pretty small and cool down very quickly (something I've confirmed by being hit by them as they come flying off my Dad's angle grinder). I would think that they'd generally just hit the aluminium and bounce off. I'd be more worried about the abrasive effect of the bits of steel flung at the aluminium damaging that lovely shiny aluminium finish more than anything.
If a piece of steel did somehow manage to embed itself in the aluminium, the steel would almost certainly corrode first.
However, all of the above is speculation, I'm really not an expert in this. You might want to look into some books on the subject; [http://www.amazon.com/gp/product/1574091131/103-0256836-4039832?v=glance&n=283155 this book at Amazon.com" looks interesting. Or hopefully a real expert will be able to comment here!--Robert Merkel 11:15, 20 December 2005 (UTC)
I remember some warning about getting the grinder too hot, after working on aluminium and iron - it's possible to start a thermite reaction? Tzarius 04:08, 22 December 2005 (UTC)
Nope. Not in this situation...remember, those sparks are caused by friction, and are just hot shavings of metal. They are rather small, and by the time they hit the aluminum, I would expect them to be relatively cool, and not do much damage to the aluminum. It would not initiate any significant chemical reaction. Well, I suppose you can stretch this a bit, and say that the shavings might scratch the surface, which causes it to oxidise, but this is a good thing - when aluminium oxidises, the coating is actually a protective one - it is not like iron where the oxide (rust) falls off and causes structural damage. --HappyCamper 04:12, 22 December 2005 (UTC)
Except that most people find the white aluminum oxide ugly as compared with shiny polished aluminum, especially when it appears as spots, making the aluminum look like it has a disease. StuRat 23:54, 22 December 2005 (UTC)
Would it be possible for the Wikipedian who asked this question to take pictures? That would be great for articles here! --HappyCamper 00:57, 23 December 2005 (UTC)

Accelerometers[edit]

How does an accelerometer work, where can I get one, and how much would it cost? Please help, Max. 216.209.153.57 15:16, 19 December 2005 (UTC)

With a quick Froogle search, electronic accelerometers go for about $100-200. Did you check out the article to see how they work? — Asbestos | Talk (RFC) 16:18, 19 December 2005 (UTC)

The article doesn't say how they work; it's almost a stub. Max 216.209.153.72 23:00, 19 December 2005 (UTC)

I could beef that article up (whoops I was thinking of accelerograph), but it's more oriented towards seismic accelerometers. (There are many types that all work differently.) In general it is difficult to get a good accelerometer up and working. There are some lab demo kits for the 'cheap & cheerful'. Most accelerometers just output a voltage; then you need a data acquisition card and software to analyze the results. For seismic work, I always wanted a small laptop kit for measuring equipment resonance, but everything is very expensive. --Zeizmic 14:59, 21 December 2005 (UTC)

Climbing stairs[edit]

I climb eight flights of stairs several times a day to my office. Which would give me the most benefits of exercise, taking them singely or two-at-a-time? (Using any definition of "benefits of exercise" you think fit).

Asbestos | Talk (RFC) 16:16, 19 December 2005 (UTC)

Well, I don't if anyone could really give a factual answer to this, but I think it goes like this. When you take two stairs at a time it equates to taking a larger stride, but one stair at a time would turn out to a longer distance. So, I would say taking one stair gives you more than or equal to the amount of exercise that you would get from taking two stairs at a time.--Ridge Racer 18:30, 19 December 2005 (UTC)

This is practically equivalent to "should I life small weights for many reps or large weights for a few reps?" The answer depends on your goal. Do you want to build endurance or strength? Longer strides will build strength and more short strides will build endurance. As for the excercise of stair-stepping, I am influenced by the hypertension studies all around me in the hospital where I work. If your heartrate is not elevated for 20 minutes, it is not effective cardiovascular excercise. Then, a joke made by a doctor at a conference I attended where a similar question was asked: "Why not bunny hop each step? That will be a workout you won't forget." Just to note, I work on the 12th floor and the doctors try to force us to use the stairs. I usually cheat and ride the elevator up to the 11th floor and then walk up the last one. --Kainaw (talk) 23:52, 19 December 2005 (UTC)
Doesn't it look suspicious when you arrive fit? Normal people would be panting after climbing 12 floors. Anyway, it's indeed the amount of effort you put into it. I once walked a marathon. I even carried a daypack and it was up and downhill over fairly uneven tracks. This took me over 10 hours. But I'm confident I couldn't run a marathon. So faster means more exercise. DirkvdM 08:57, 20 December 2005 (UTC)

Infared LED[edit]

I'm searching for this article, please give me some infos about that. Thanks

infrared and Light-emitting diode Dominick (TALK) 18:03, 19 December 2005 (UTC)

More specifically for infared light emitted by LEDs try Infrared#Communications.--Ridge Racer 18:07, 19 December 2005 (UTC)

Upgrading Windows ME to Windows XP...[edit]

Is it at all possible to upgrade from Windows ME to Windows XP Service Pack 2?--Archducky Duck

Yes, but you would need to back up your stuff, then reformat your hard drive and reinstall with XP SP2.--Ridge Racer 18:24, 19 December 2005 (UTC)

Are you positive? Because I'm on the verge of buying the XP SP2 CD on eBay, and I wouldn't want to waste my money...--Archducky Duck

If you have the software and the licence, there shouldn't be a problem. Mind though that the system requirements for windows XP may give you some problems. See [44]. -- Ec5618 19:02, 19 December 2005 (UTC)

It is not necessary to reformat the hard drive in order to upgrade Windows ME to Windows XP. In the process of updating, setup determines whether the file system should be changed from FAT32 to NTFS, based on some criteria I am unaware of-- perhaps compatibility with programs already installed. (After the upgrade, it is possible to change the file system once from FAT32 to NTFS; this has some benefit as regards resistance to file corruption, and will permit native file encryption if you're upgrading to Windows XP Pro rather than XP Home). Some old programs that directly access the hard disk may not work if you change to NTFS. Also, as Ec5618 mentioned, there are many hardware issues, and much legacy hardware that would otherwise be compatible with XP does not have approved XP drivers available. There is an XP upgrade advisor wizard that runs automatically during XP setup which can point out these issues before you make the upgrade. Alternatively, you can run the wizard as a standalone program. see: Windows XP Upgrade Advisor--
Mark Bornfeld DDS
Brooklyn, NY 21:11, 19 December 2005 (UTC)

Disruption of Lunar Orbit[edit]

What would happen on earth if an asteroid or meteor strike knocked the moon out of its normal orbit?

There would be a huge distruption of the tides, possibly causing tsunamis and other such events. If the knock was big enough, it might distrupt the Earth's orbit. I guess the moon could also crash into the Earth if the blow knowcked it inwards or slowed it down. — Asbestos | Talk (RFC)
What would happen if the Moon did impact the Earth? Would gravity immediately crush the Earth+Moon combination into a sphere, or would it stay funny-shaped for some time? I'm guessing there would be a pretty major impact winter regardless... —Keenan Pepper 21:06, 19 December 2005 (UTC)
The moon would break up first when it reached its Roche limit, forming something roughly like Saturn's rings. - MPF 23:59, 19 December 2005 (UTC)
No, that would depend on the structural integrity of the moon. The Roche limit refers to bodies held together only by gravity. The moon's material strength and resistence to tensile stress would keep it intact inside it's Roche limit. I don't know how strong the moon is, but I would assume it could make it all the way to impact before it broke apart. - Taxman Talk 16:27, 20 December 2005 (UTC)
I was thinking that too. The roche limit isn't all that far from the Earth's surface anyway (about 1.5 times the radius). So, how long would it take Earth+Moon to be crushed into a sphere? Would the pressure make the rock flow as a liquid? —Keenan Pepper 19:32, 20 December 2005 (UTC)
Yes, the Earth/Moon combo would become molten, with all the oceans vaporized, and would quickly settle back into a slightly larger sphere and then cool in that shape, with a thin solid crust containing new continents and oceans. The collision might also send out several large clumps of materials that would form a series of smaller moons. StuRat 03:50, 22 December 2005 (UTC)

In the original question, "knocked the Moon out of its normal orbit" is rather nonspecific. If the Moon was deflected by a small amount, that'd be "out of its normal orbit", but there wouldn't be any major effects on the Earth. The biggest effect would probably be cultural: the length of the lunar month would change, and all cultures using a lunar calendar (such as Islam) would need to deal with that. Also, solar eclipse fans, who might already have trips planned to see eclipses over the next few years, could find their schedules all wrong.

If the Moon was deflected into a more eccentric orbit without much change to its period (the lunar month), that would mean that it would be closer when at perigee and farther when at apogee. Even a small change might noticeably affect the tides, since tidal force varies as the inverse cube of the distance. Sometimes when a coastal region is threatened by flooding, a higher-than-usual tide can cause the flood to happen; the perigee change might make that a more common occurrence. Apogee and perigee changes could also give some solar eclipses a noticeably different appearance than now.

But I suspect the intention was to imagine a more violent disruption, one that deflects the Moon into a grossly different orbit. In that case we wouldn't be worrying about tides -- the energy relase from the impact itself would be, well, astronomical. The Moon's kinetic energy, if I calculate correctly, is about 4 x 10^28 joules. If just 10% of that energy went into heat, that would be equivalent to a trillion-megaton explosion. And don't forget that the impacting body will contribute kinetic energy of its own that will also turn into heat. I don't know how to calculate it, but I would guess an impact that size would be enough to cause significant radiant heating on the Earth. Not to mention fragments splashing out, large enough that some of them could cause damaging meteorite impacts on the Earth, maybe even global-disaster-level effects.

--Anonymous, 07:40 UTC, December 20, 2005

There is a 50% chance the collision would be on the far side of the moon, in which case the radiation wouldn't be a problem for us. (The chance might be less than 50%, if the Earth provides some shielding of the near side.) Large meteors resulting from the collision might still hit the Earth, though, even if the impact was on the far side. StuRat 04:04, 22 December 2005 (UTC)
That clearly leaves us with only one option... Eliminate the moon before it eliminates us!!! But seriously, are there even any known asteroids with near enough mass to disturb the moon that greatly, if they were to hit it?
I was curious about this, so I fed the problem to the Impact Effects Calculator. Assuming the Moon were to simply halt in its orbit, dropping straight down onto Earth and colliding after 2.5 hours, the energy of its impact would be 2.92x1032 J, just exceeding the combined gravitational binding energy of both objects (2.285×1032 J). This seems to be reflected in the calculator's estimate that the crater diameter would be 11,300 km. At least someone on the far side of Earth should have twenty minutes of relative safety. ᓛᖁ♀ 16:58, 22 December 2005 (UTC)
And that calculator probably assumes that the crust would not be ruptured. When it does, the effect would be even more dramatic. StuRat 23:46, 22 December 2005 (UTC)

Antimony[edit]

I wante to know if Antimony bioaccumulates like Lead or Mercury.

Antimony is more like arsenic when it comes to poisoning. --Kainaw (talk) 20:13, 19 December 2005 (UTC)
Antimony died by falling on his sword, but Cleopatra died from snake poison.
...I couldn't resist. --Sum0 20:39, 19 December 2005 (UTC)
And here I thought antimony was another name for reverse-alimony. LOL. StuRat 03:42, 22 December 2005 (UTC)

Physics lecture[edit]

Many years ago when I was taking lower division physics my professor remarked that every equation used in physics can be derived from one of eight fundamental equations, one of which was F=ma (the only one I remember). What might the others be?

F=ma doesn't really work in modern physics. Max 216.209.153.72 23:02, 19 December 2005 (UTC)
But F=ma would be pretty helpful for lots of stuff, and there are seven more. That being said, I couldn't begin to guess which eight he might've meant. Some important ones are:
Oh, heck. I really have no idea, and it'd take pages to explain what's up there already. ;-) -- SCZenz 23:11, 19 December 2005 (UTC)
I think the non-logged in user above means that F=ma is wrong, while, say, F=dp/dt is equivalent classically, but is also correct in modern physics sense. --Ornil 04:28, 20 December 2005 (UTC)
  • E=hf is quite important. --Bob Mellish 23:14, 19 December 2005 (UTC)

Why not just go with 2: Einstein field equations, and the Standard model equation of motion? -lethe talk 23:25, 19 December 2005 (UTC)

I remember hearing something similar. Also, Hawking wants to describe everything with one superformula. So how may are there now? Or what if we limit it to 'traditional physics'? The SI base units are mass (m, kg), time (t, s), length (l, m), electrical current (I, A), temperature (T, K), quantity of matter (n, mol) and luminous intensity (I, cd). How do they relate? The SI derived units give relations. Which of these are basic? Of course Hertz doesn't count because it is only expressed in one unit (the second). Then there's

  • Force: F = ma
  • Energy: E = mv²

Power doesn't qualify either because it's expressed in terms of energy and time, which we already have. Same for many others. But then there's

  • Electric charge: V = It

Confusingly, 'I' can mean two things. Are there no unambiguous symbols? (I looked these up in a science table book. Shouldn't those be given in those articles?). Anyway, on I go:

  • Magnetic flux: how do you write that?

Oh dear, this is too long ago. I think the principle of what I mean is clear. But someone more knowledgeable could do this much more easily. DirkvdM 09:56, 20 December 2005 (UTC)

The best answer is probably that what your professor told you is inaccurate, if not downright wrong. If you're looking for important formulas in classical physics, then you should definately mention Maxwell's equations and the laws of thermodynamics. It would make more sense to say that all measurable quantities can be measured in units derived from 7 fundamental units, as indicated above. Hope this helps. Siebren 12:57, 20 December 2005 (UTC)

<MATH>[edit]

  • why is does it make <math></math> into , when theres nothing inbetween the tags'?—Preceding unsigned comment added by 152.163.101.12 (talkcontribs)
    • Interesting "bug"! iso - 8859 - 1 is the standard character encoding on TeX, I'd suppose. Who'd have thought it'd show up like that! ☢ Ҡieff 00:41, 20 December 2005 (UTC)

December 20[edit]

Hydrocarbons[edit]

Where can i find properties of hydrocarbons, and how they affect characterization and use for gasoline? Ive been looking for hours

Did you try the article on gasoline? Do you have a specific question? —Keenan Pepper 01:08, 20 December 2005 (UTC)

--Thank you, i think this is exactly what im looking for :D, i could have sworn i checked here before though, been to so many sites..... thanks again

  • Depending on which properties you're looking for the Handbook of Chemistry and Physics may also be of use to you. - Mgm|(talk) 12:28, 20 December 2005 (UTC)

The chemical sentence for glucose[edit]

I don't understand what "chemical sentence" means, but the formula for glucose is C6H12O6. —Keenan Pepper 01:04, 20 December 2005 (UTC)
The glucose page gives it as 6-(hydroxymethyl)oxane-2,3,4,5-tetrol - MPF 14:01, 20 December 2005 (UTC)

3 bluescreens in 3 days[edit]

...is three too many. Dell Inspiron 5100, 384MB, XP. It seems to happen after I go away for a few hours, leaving the laptop on, with the lid closed. The blue screen has no useful information, only hex addresses. Windows keeps a data log which I've forwarded to the Microsoft web site; but the automated analysis there simply says the problem was caused by an (unknown) driver. I haven't installed any drivers for a very long time. I did perform two system restores, the first to the day previous and the second to two weeks earlier. A non-Dell tech suggested it might be a memory problem, citing a previous case with the same computer. He said I had 256K and 128K memory chips and that if one of them wasn't working it could cause a pointer error, corrupting memory and causing the crash. Is this reasonable? What should I do? Thanks, Halcatalyst 01:52, 20 December 2005 (UTC)

  • Well, to test if the memory is bad, use Memtest86. It takes awhile to run but is pretty good in seeing if that's the source of the problem. If is, you figure out which RAM card is bad and replace it, not very hard. If it isn't RAM, then you have to try other things. --Fastfission 03:05, 20 December 2005 (UTC)
    • It lost me when it asked me to enter the disk image source file name. I'm afraid I don't have nearly enough technical expertise to use the tool. Thanks anyway, Fastfission. Halcatalyst 03:24, 20 December 2005 (UTC)
      • Just download Ultimate Boot CD, burn it to disk, and run it from that disk instead. Easier, and you get a bunch of other diagnostics tools too. TERdON 16:27, 24 December 2005 (UTC)
  • I had almost the same thing with an older Gateway. Turned out the heatsink on the CPU had become loose. Put on some lithium grease (better to use thermal if you have any) and tightened (but laptops are tricky beasts to take apart and put together). Now it can run forever, compiling Linux kernels. --Zeizmic 23:14, 20 December 2005 (UTC)
Your computer has determined that you are damaging your health by spending too much time online viewing porn (if that's actually possible), and decided to shut down to protect you. StuRat 07:40, 22 December 2005 (UTC)

Why do we see our breath on a cold day but not on a warm day?[edit]

Our cells produce water when they undergo cellular respiration to produce energy. Glucose, processed from our food, is broken down into pyruvate in the cytoplasm, protons (positive hydrogen ions) and electrons extracted from it, which is then oxidised with oxygen to yield water. This produces water in our breath when we exhale. Heat, due to entropy in cellular respiration, makes this water particularly warm. This allows more water to be dissolved into the air. On a warm day, our breath isn't much hotter than the surroundings, and it loses very little heat, thus keeping most of the water dissolved (transparent/hidden). On a cold day, the saturation capacity of our breath decreases immensely as it loses heat to the cold air, making the water in our breath condense. Thus the water particles originally produced in our mitochrondria become visible. -- Natalinasmpf 02:24, 20 December 2005 (UTC)

An incredibly complex answer is given above, but the basic point is indeed that the water vapour is usually free to remain an invisible gas, but on cold days it condenses to tiny (visible) droplets of water. Notice how the steam from a kettle is invisible until it's a few centimetres away from the nozzle — the water cools and condenses. -- Ec5618 12:02, 20 December 2005 (UTC)
I'd also note that the incredibly complex answer above is trying to be too clever for its own good. Most of the water we exhale isn't the product of cellular respiration; it's the same stuff we consumed as part of the food and beverages in our diet. It makes its way through the body–as a component of blood plasma, lymph, or miscellaneous interstitial fluid–and some eventually ends up coating the surface of the lungs. (From there, it readily evaporates as described.) TenOfAllTrades(talk) 16:49, 21 December 2005 (UTC)
The sources of heat and moisture in one's breath are completely irrelevant to the question and should be a "given" unless the questioner asks for more detail. StuRat 03:06, 22 December 2005 (UTC)
But I was bored. Alas. -- Natalinasmpf 03:42, 22 December 2005 (UTC)
Ok, we can forgive you then. I am looking forward to your recipe for lemonaide that starts with the mitosis cycle for cellular reproduction in the lemon tree. Don't forget to list the number of chromosmes ! LOL. StuRat 07:33, 22 December 2005 (UTC)
On a side note, this is the same effect which causes jets to leave a white trail in the sky.
Jet engines undergo cellular respiration?? Jasongetsdown 00:43, 26 December 2005 (UTC)

In which layer of the atmosphere is the aurora borealis displayed? What is the cause of this natural light show?[edit]

Welcome to Wikipedia. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. Anyhow, see aurora borealis. -- Natalinasmpf 02:52, 20 December 2005 (UTC)

More circuitry questions[edit]

I know I know, I ought to just figure this stuff out already, right? Well, until I do, here goes:

On the CD40106 DIP I mentioned above, the schematic calls to connect components to pins 1-6, in 2 pin pairs. Is it kosher to connect the parts that were supposed to go to pins 3 and 4 instead to pins, say, 10 and 11? It would make layout of my board much easier, because as it stands, all my parts are on one half of the board.

Oh, and if any of you have any good reference to websites or books that have instruction on basic circuitry, I think we all would appreciate that :). I find a lot of stuff on basic electronics, but it's largely theorhetical and doesn't really help me once I start to build. Thanks! --ParkerHiggins | Talk 04:03, 20 December 2005 (UTC)

  • Yes, since that IC has six identical copies of the same gate, you can swap any gates over as long as you follow the correct pinout, e.g. instead of pins 3 & 4, use pins 11 & 10. Note you have to make sure you get the input and output in the right order.
  • Absolutely the best electronics book for beginners, IMO, is this one: [45]. Seems not to be in print anymore (you used to be able to buy it from Tandy/Radio Shack), but it covers everything you need to know with a strong emphasis on practical rather than theoretical. --Bob Mellish 04:32, 20 December 2005 (UTC)

Ice[edit]

If I add some ice (0 degree celcius) to hot water of 40 degree celcius, after 5 minutes, lets say that the hot water became 38 degree celcius, what would the temperature of the ice be? Would it remain 0 degree celcius or the temperature of the ice increases? --165.21.83.240 07:20, 20 December 2005 (UTC)Naruto90

When ice gets above 0 celsius, it is no longer ice. There is a period of latent heat, where added energy does not increase the heat, but after that, the ice melts. --ParkerHiggins ( talk contribs ) 07:23, 20 December 2005 (UTC)
(My answer was longer, and had formatting issues, but, pretty much the same thing):
The ice would melt, and become water, 40oC is certianly hot enough to change it all the way to liquid phase, thermodynamically though, you're right, ice melting in hot water could be broken down into
Water(solid,0oC)-->Water(liquid,0oC)
&
Water(liquid,0oC)-->Water(liquid,near40oC
seperating out the phase change, and the temperature change, while remaining energetically equivalent to the origional reaction,
Water(solid,0oC)-->Water(liquid,near40oC)
so yes, basically, it would melt--Aolanonawanabe 07:28, 20 December 2005 (UTC)
Depends. No quantities are given. Suppose you threw an iceberg 'into' a puddle of warm water? :) But couldn't the relative quantities be calculated based on the water temp dropping from 40 C to 38 C in 5 mins? Anyway, the answer stays the same. The ice (if any, but the question implies there is some, unless it's a trick question) will be at 0 C. DirkvdM 10:06, 20 December 2005 (UTC)
To answer the literal question, if any ice remains, it would be at 0 °C. At equilibrium, the whole system will be at the same temperature. As explained above, what happens depends on the relative amounts of ice and warm water. If there is only a small amount of water, it be sufficient to melt only part of the ice before it was cooled to 0 °C; you would end up with an ice-water mixture at 0 °C. If there is sufficient water, the ice will all melt and the result will be all water at some temperature between 0 °C and just below 40 °C (of course, depending on the relative amounts). — Knowledge Seeker 02:12, 21 December 2005 (UTC)

Fast[edit]

Can anything or is there anything that is able to move faster than the speed of light??? If no, why can't anything move faster than light???

165.21.83.240 07:19, 20 December 2005 (UTC)Naruto90

If you take a look at Lorentz transformations you will see that, if v comes greater than c, the square root becomes imaginary. Therefore, nothing can move faster than speed of light (just by mathematical reasoning). GTubio 16:27, 24 December 2005 (UTC)
Things can appear to move faster than the speed of light in vacuum (c), but no matter or information can actually travel faster than c. According to special relativity, anything that appears to be moving faster than light to some observers will appear to be going backwards in time to other observers. In other words, faster-than-light travel is equivalent to time travel. —Keenan Pepper 07:37, 20 December 2005 (UTC)
Nothing can move faster than the speed of light in a vacuum. But things can move faster than the slower speed of light in non-vacuum situations. When a fast-moving atomic particle exceeds the speed of light in air or in water, it produces a shock wave (a bit like a sonic boom). For more details, see Cherenkov radiation. - MPF 11:31, 20 December 2005 (UTC)
Speed is a relative concept. I could be moving at 0.5 lightspeed (as measured from Earth), drop a buoy, and fire my boosters to accelerate to another 0.5 lightspeed (as measured from the frame of reference of the buoy). Oddly, to observers on Earth I will not be moving at the speed of light, and since time moves differently for me, They will see me moving at about 0.7 lightspeed. I could drop another buoy and accelerate again (instinctively one would say I was moving at 1.5 lighspeed, but to observers on Earth I will be moving at about 0.8 lightspeed). In my frame of reference, things would be different.
Consider that speed is distance times time, and that time is a relative concept.
Light, in my understanding, is a somewhat timeless concept. It moves at the maximum speed in our frame of reference, but from the point of view of the photons themselves they reaches their destination at the moment they are created. -- Ec5618 11:58, 20 December 2005 (UTC)
You may also want to read the answer to the question Is Faster Than Light Travel or Communication Possible? in Usenet Physics FAQ if you want to learn more about the details. – B jonas 12:45, 20 December 2005 (UTC)
See tachyon for a description of a theoretical superluminal velocity particle. StuRat 02:57, 22 December 2005 (UTC)

Two-way radio[edit]

Is there any two-way radio in the market that has encryption feature? roscoe_x 08:40, 20 December 2005 (UTC)

how do you make a radio[edit]

i want to make a simple radio reciver and transmitter for my science fair .can anyone help my in my quest?

See crystal radio, particularly the external links. Proto t c 10:40, 20 December 2005 (UTC)

Prefixes[edit]

Why do we have prefixes like kilo- and mega- when they mean exactly the same as 'thousand' and 'million'? The overview at SI prefix shows there is such an equivalent for each prefix. So what is the use of using different names than the ones already generally known? Well, one reason might be the ambiguity of a word like 'billion', according to culture. But is that the only reason? DirkvdM 10:22, 20 December 2005 (UTC)

Of course centi for hundreth. my guess is that the prefis are easier to work with and have unique 1 letter codes that are unambiguous. Thousand, ten, thousandth all start with a T. i emphasise this is a guess. David D. (Talk) 10:31, 20 December 2005 (UTC)

Well, believe it or not, there was a time when English wasn't "already generally known" and ancient Greek, like Latin, provided an acceptably neutral core for a non-nationalist scientific language in the 18th and 19th centuries. The prefixes are part of the metric system, which dates to the early 19th century and has lots of advantages. alteripse 10:35, 20 December 2005 (UTC)

Another minor advantage of the prefixes is that they are shorter when written out. Per alterprise, cultural neutrality probably played a big role. Note that the metric system was a French development; if we were to use the vernacular we would have millemetres, centmetres, and dixmetres—not thousandmeters, hundredmeters, and tenmeters.

Meanwhile, you can see the potential for trouble if each region were to use its own language in the units. The British wouldn't have been willing to adopt a system that used French prefixes, so going back and forth from the Continent would have required replacing all those thousandmeters (tm?) with millemetres (mm?). Using the Greek-derived prefixes cuts down on the confusion; everyone can unambiguously use kilometers (km). TenOfAllTrades(talk) 12:24, 20 December 2005 (UTC)

To see an illustration of potential difficulties, look at the early history of railroading where different nations had different widths between the tracks, meaning a lack of global standards, so trains were designed to run in a particular nation. I have heard it tell that this was done deliberately because some leaders were sufficiently farsighted and paranoid to realize that an army traveling by train could get into their nation pretty fast and economically if their trains required same width between wheels as everyone else. I never learned whether that was ancient history urban legend or not. User:AlMac|(talk) 21:46, 20 December 2005 (UTC)
That problem certainly occurred in Australia when it was a bunch of separate British colonies and not a unified nation (1901). Most of the colonies had unique rail gauges. Travellers between Sydney and Melbourne, the capitals of New South Wales and Victoria, had to change trains at Albury. The problem was not finally fixed till the 1960s, believe it or not. That's why Albury had one of the world's longest railway platforms. JackofOz 22:42, 20 December 2005 (UTC)
A change in gauge (between Brunel's Broad gauge and Standard gauge) is also the reason why Gloucester has the longest railway platform in Britain. Thryduulf 00:53, 26 December 2005 (UTC)
From Track gauge, In the nineteenth century, Russia chose a broader gauge. It is widely believed that the choice was made for military reasons, to prevent potential invaders from using the Russian rail system. Shimgray | talk | 20:02, 21 December 2005 (UTC)
And in Spain the gauge was also wider, for the same military reasons. Only after Franco did they start to change to the European standard gauge and I'm not sure if that job has been finished yet. Well into the 1980's one still had to swap trains at the border. DirkvdM 12:31, 23 December 2005 (UTC)

chemistry[edit]

Are diamonds compounds?

No, diamonds are pure carbon. They may contain impurities, but the diamond itself is comprised of one element. Proto t c 12:08, 20 December 2005 (UTC)
You might be confusing diamonds with Cubic Zirconium, which is a compound resembling diamond.
No, diamond is an allotrope of carbon GeeJo (t) (c) 22:02, 26 December 2005 (UTC)

Airplane doors[edit]

Is it true that on passenger airplanes it is impossible to open the door mid-flight due to the differential in air pressure between the inside and outside of an airplane cabin? Regards, Gallaghp

  • There's probably safety locks on those doors preventing them from opening but I think it's relatively easy to do so if that wasn't the case. Airplane cabins are pressurized to approximately the same pressure as people feel on the ground, which would be higher than the low pressure of the air outside. High pressure inside versus low outside, would make opening a door relatively easy. It's the exact opposite of trying to open a door underwater at the bottom of the sea. The pressure there is a lot higher than on ground level because there's a lot more air (and water) above you applying pressure. So underwater, the pressure outside is high enough to keep you from opening the door. - Mgm|(talk) 12:35, 20 December 2005 (UTC)
    • Mgm, that would depend on your definition of the phrase "same pressure as people feel on the ground". Commercial jets are not pressurized to pressures one might feel at, for instance, sea level. The pressure within the airplane would be equal to that of a few thousand feet above sea level. See Cabin pressurization for more info. Dismas|(talk) 13:35, 20 December 2005 (UTC)
      • Boeing's answer on the matter is that the door cannot be opened during pressurised flight. Their website (at least that part) doesn't explain why, but my guess is that the door has a plug design. When the lever is pulled, a plug action is observed where the cabin pressure makes it impossible to push the lever back. You will notice that I have completely avoided disucssing the design of this system, becuase I have no idea how it works.--Commander Keane 14:10, 20 December 2005 (UTC)
    • Mgm, I'm pretty sure that the doors on (most, if not all) commercial airliners open inward; consequently you would need to pull the door open against the air pressure difference. (They're plug-type doors; they are larger than the opening in the cabin that they seal.) At altitude, the pressure difference between the cabin and the surrounding air is about 8 psi (55 kPa), which works out to aboute ten tons of force on a typical cabin door. TenOfAllTrades(talk) 14:34, 20 December 2005 (UTC)
      • I have never come across a commercial aeroplane where the door opens inwards. All Boeings and Airbuses I have traveled on open outwards. Lack of interior space is one reason why this is so. -- SGBailey 00:50, 29 December 2005 (UTC)

Dismas is correct, but the pressure difference between the inside and outside of the plane is still substantial, up to about 1/2 atmosphere, which means that the force on a normal-size door is something like 20,000 pounds (10,000 kilograms-force or 100,000 newtons).

What Mgm is missing is that airliner passenger doors are normally designed to open inward, and so the answer to the question is yes. This design means the latch only has to be strong enough to keep them from coming open due to wind, vibration, and so on when the aircraft is near the ground; it doesn't have to resist the huge force created by the pressure difference. I think I've heard of a model of airliner that does have outward-opening doors, but it would certainly be the exception.

In some cases cargo doors don't have space to open inward, in which case they do require latches that strong. Consequently, the failure of a cargo door can be disastrous. But with the mechanism normally locked, it would still be impossible to open it deliberately in flight because the pressure would keep the bolts from sliding.

--Anonymous, 14:30 UTC, December 20, 2005

You should watch a program about how a boeing door locks failed and the parents of a New Zealander who died in the crash, who pushed and pushed and pushed and pushed and came up with the truth. He was an aeronautical engineer or something similar. I might I add that it wasn't easily accepted by the air transport authorities, the door locks were made from very, very lightweight aluminium that was known to be and previously ordered to be changed, by boeing, so that it wouldn't fail.

Very interesting

Not all airplane doors open inwards, however, the ones that open outwards have a double action mechanism whereby they cant inwards before swinging out (the MD-80 is an example). Also, Anonymous is correct about cargo doors. The A320 series is an example of cargo doors that swing outwards, but their cargo doors are so heavy that they're only articulated by a motor, not by hand. I'm not sure if the emergency exit doors on commercial airliners can be opened in flight, I doubt they'd want any mechanism that would impede their opening at all. IIRC, some 60's-era aircraft even had explosive bolts for the emergency exits. -User:Lommer | talk 02:03, 22 December 2005 (UTC)
I would guess that those airplanes with cargo doors that open outward do not have pressurized cargo compartments. Otherwise, the huge forces acting on the cargo doors would be difficult to control with any latch mechanism. StuRat 02:37, 22 December 2005 (UTC)
Pressurizing the cargo compartment allows the pressure hull to be more or less a cylinder, which is a strong shape. If the cabin floor was part of the pressure hull, it would need reinforcement all along the edges where it meets the walls. Also, an unopressurized cargo compartment could not be accessed in flight even if some emergency made it desirable. These issues are more important than the cost of a strong latch on the door. --Anonymous, 10:50 UTC, December 22
A "strong latch" does not begin to describe it. If there was only a 1 psi difference in pressure from the interior to the exterior of a large, 120x150 in cargo door (say on a C-130), the force on the door during flight would be 9 tons ! StuRat 23:38, 22 December 2005 (UTC)

And yet if you search on c-130 and "pressurized", you will find, for example, this page that confirms that the C-130's cargo compartment is indeed pressurized. --Anon, 02:35 UTC, December 23

Indeed, I have flown on a B-727-200F. I was seated in a jumpseat in a small area just aft of the cockpit, separated from the cargo by a divider, but this was not an airtight divider (I could look around its edges and see the cargo.) The 727's cargo door is the type that opens outward under the control of a motor, and it's something like 140" x 88". kmccoy (talk) 15:03, 23 December 2005 (UTC)

particle technology[edit]

what is meant by sub sieving and what is its importance? --61.17.183.141 12:36, 20 December 2005 (UTC)--

sexual disorder[edit]

Can anybody help me, I suffer from hasty disscharge of sperm

Yes, someone more than likely can help you. I'm guessing it's nobody here though. Dismas|(talk) 13:40, 20 December 2005 (UTC)
That was not helpful. See premature ejaculation. Proto t c 15:03, 20 December 2005 (UTC)
  • You didn't say under what conditions this occurs, but my guess is that should practice the "stop and go method" of masturbation to teach your body to hold out and not ejaculate too soon. - Mgm|(talk) 20:47, 20 December 2005 (UTC)

The Diesel Engine[edit]

I recently heard a lecture about Herbert ?-Stewart or Stuart, I forget his mothers name, however I can easily get it again though it's too late tonight.

I was stunned, bemused, absolutely enthralled.

It seems that he patented the fuel oil compression engine specifics in 18??, in England, this being on the record.

Why then is Rudolf Diesel credited with the "INVENTION" when he patented his specifics two years later?

I will put the entire lecture that I heard on this page

I understand that there have been many Herbert ?-Stewart or Stuart lectures over the subsequent years however it seems that the community has seen fit to believe the promotion put forward by Rudolf Diesel that he alone was responsible for the invention of the 'fuel oil compression engine'.

It is common for multiple persons to be developing technology at the same time however it has been the accepted practice that the first patent is credited with the invention of the device.

It is a matter of record that Herbert ?-Stewart or Stuart, did build a working engine however it is not known, at least by me, at what point that the good professor Diesel built an engine.

The working fuel oil compression engines that were built in Englang subsequent to Herberts patent were not named as Diesel engines. They were given other more generic or builder specific names.

I hope that there are others that can elaborate upon this as the inventor died a bitter and disappointed man subsequent to the media picking up upon the very public, well funded campaign by Professor Rudolf Diesel.

I have no malice towards Professor Diesel however it is well observed that the German aristocracy was very adept at using the media to put their ideas forward.

Me personally, well, I think that the media has always allowed itself to be used and melded by people who understand how powerful it is, though not everyone who understands its power wants to exploit it.

  • Herbert Akroyd Stuart is the person you're after. This sort of thing is hardly unusual - who invented what, and who made the most significant advance is often convoluted by claim and counter-claim, and sometimes the "winner" (in terms of who gets the credit) isn't necessarily the strongest candidate. The Wheatstone bridge wasn't invented by Wheatstone, and Snell was 637 years late when he discovered Snell's law. The invention of the laser is a more modern example. See James Burke's old book/TV series "Connections" for a look at a bunch more. --Bob Mellish 17:05, 20 December 2005 (UTC)

Wet cutting (Wet saw)[edit]

What is the difference in applications between wet and dry cutting? Such as a wet tile saw, wet concrete saw- when is a wet saw preferable and why is it used? 83.5.231.66 14:16, 20 December 2005 (UTC)

The water removes the substrate that is cut to get it out of the way and typically works as a coolant for the saw blade. So I guess it's going to be used for cutting harder materials. I'm no saw expert, this is just what I recall from watching This Old House or whatever. - Taxman Talk 16:14, 20 December 2005 (UTC)
Water or some other liquid is also so used in drilling, where the buildup of material and heat in a deep hole can cause the drill bit and/or the material to fail. Lubricants are fequently used, as they also have the desirable effect of reducing friction. StuRat 02:25, 22 December 2005 (UTC)
Also wetting keeps down the saw dust; that is, it helps to keep it from flying around and spreading all over the place. 205.188.117.71 20:23, 26 December 2005 (UTC)

Sugar soap[edit]

Sugar soap is a chemical used for cleaning. I had never heard of it when I lived in the United States, but then when I moved to Australia I found that its is very commonly available here. Its main use, apparently, is for washing walls, but I wonder about other applications. Perhaps in America it has another name with which I am familiar. Is it dangerous? Are there other cleaners with which it can be mixed, such as ammonia? And, especially, I just gotta know about the name; Why is it called "sugar soap"?

I found Wikipedia about three weeks ago, and now I visit this site more often than google. This is a fantastic, in-depth, resource, and totally uncluttered with capitalistic interests.

Thanks to whoever answers my question.

We have it in the UK, too. It's a caustic substance, but I can't find its composition. Assume it's sodium hydroxide or something similar. Here's a data sheet (PDF). It's so named because, in its dry form, it looks like granulated white sugar. Chemically, it has nothing to do with sugar. --Heron 19:23, 20 December 2005 (UTC)
I googled and a some of the results actually had sucrose as an ingredient. [46] Maybe "sugar soap" refers to two different products? —Keenan Pepper 19:39, 20 December 2005 (UTC)
Ah, there seems to be some confusion. The 'sugar soap' that the submitter is asking about is apparently an abrasive and caustic powder used for cleaning walls. However, the term 'sugar soap' has also been appropriated by various other manufacturers of 'girly' bath and body products—these ones contain moisturizers, vanilla, and other floofy, frilly ingredients.
The potent, wall-scrubbing 'sugar soap' seems to vary a little bit by manufacturer. (See, for example, powder [47] and liquid [48] formulations.) The important bits seem to be sodium carbonate and sometimes sodium phosphate (caustics), and sometimes sodium silicate (an abrasive); there's also some additional non-hazardous salts that probably are mildly abrasive and/or filler. To find the (hazardous) ingredients in a product, try searching for the product name plus the acronym MSDS. TenOfAllTrades(talk) 19:50, 20 December 2005 (UTC)

What are the physical features at the ocean shore?[edit]

They vary widely, from gently sloping sandy beaches, to rocky shores, to steep cliffs. StuRat 02:08, 22 December 2005 (UTC)

Speed of light in a vacuum[edit]

How do we know what the speed of light in a vacuum is if we can't even create a perfect vacuum? Would it be possible for a molecule a fair distance away to affect light electromagnetically, or does it physically need to get in the way? Thanks, Zhatt 22:39, 20 December 2005 (UTC)

You can actually infer its theoretical speed from Maxwell's equations - I think... --HappyCamper 01:30, 21 December 2005 (UTC)
Right, it's related to the permittivity and permeability of the vacuum by c = {1\over{\sqrt{\epsilon_0\mu_0}}}. —Keenan Pepper 02:06, 21 December 2005 (UTC)
While it's not easy to create good vacuum in laboratory conditions (i.e. on the Earth), the speed of light is much easier to measure using astrological measurements than in a laboratory, and in the space there's already pretty much a vacuum. —Preceding unsigned comment added by B jonas (talkcontribs)

That's not true. It's actually much easier to measure the speed of light in the laboratory. Furthermore, it's possible to create vacuums in the laboratory comparable to interstellar vacuum. However, a perfect vaccum doesn't exist, therefore a perfect measurement of the speed of light doesn't exist either. This isn't much cause for concern, because no measurement anywhere is perfect. The precision of measurements is constrained, even in principle. Finally, with the modern units, the speed of light is a defined exact number, so if you're using the modern units, you're measuring your meterstick, not the speed of light, no matter what experiment you're doing. -lethe talk 12:15, 21 December 2005 (UTC)

"the speed of light is much easier to measure using astrological measurements than in a laboratory" - no, the only thing you can measure with astrological measures, is the speed of dark (i.e., how long it takes the world to return to the dark ages) - MPF 15:42, 21 December 2005 (UTC)
If we assume the speed varies at a predictable rate relative to the purity of the vacuum, we could look at the speed of light in a 90% vacuum, a 99% vacuum, a 99.9% vacuum, etc., and extrapolate the theoretical speed at a 100% vacuum. This does assume, however, that nothing "strange" happens near a 100% vacuum. For example, there could be an as yet undiscovered "supervelocity" where the speed of light goes to infinity at a 100% vacuum, similar to superconductivity near absolute zero on the temperature scale. While there is no evidence that such an effect will occur, and no such effect has been measured even in the sparsely populated intergalactic spaces, and no current theory predicts it, anything is possible. Thus, testing with progressively purer vacuums (as we are able to produce them) would eventually enable us to find any such effect, if it exists. StuRat 02:04, 22 December 2005 (UTC)
Also, don't forget that we know that the speed of light is exactly 299,792,458 meters per second because the definition of the meter is the distance light travels in a vacuum in exactly 299792458-1 second. — Knowledge Seeker 03:55, 22 December 2005 (UTC)
Nothing weird would happen in a 100% vacuum because the only reason a 100% vacuum is needed is so the photons won't crash into anything. The light "thinks" it's in a 100% vacuum all the time - until it crashes. Max 216.209.153.79 14:21, 22 December 2005 (UTC)

December 21[edit]

Zinc oxide powder[edit]

How much Zinc Oxide should be used in a 4-oz. bottle of body lotion?

From Google it looks like sunblock usually has between 2% and 10% zinc oxide, so a 4 ounce bottle could have anywhere from 2 to 10 grams. —Keenan Pepper 20:36, 21 December 2005 (UTC)

human body[edit]

can you please tell me the differnces between enzymes and hormones? thank you

enzymes generally act locally to facilitate specific processes, hormones usually have a global, systemic effect. The articles on each should have more detail. Night Gyr 05:06, 21 December 2005 (UTC)

An enzyme is a catalyst. A hormone is a signal. alteripse 06:27, 21 December 2005 (UTC)

Pruning of chikoo/sapodilla trees[edit]

Would you like to inform me when a subject tree is pruned, it produces significantly low fruit formation in subsequent crop/years. Why? Pl. inform me and oblige. Thanks.

The Chikoo is an evergreen, and thus pruning is not efficient. You should however remove sick or dead parts of the tree. Pruning of buds will for most plants increase yields if done in moderation the next season since the plant will not waste energy on unhealthy or unsuccessfull buds. Overpruning is none to reduce the ammount of fruit and its quality in all plants. Since the Chikoo produces two crops per year and flowers year round pruning saves little energy for the plant. --Sreyan 13:01, 21 December 2005 (UTC)

Freesoft Unicode <-> ASCII conversion tools?[edit]

I need a Windows/DOS software tool that allows me to batch convert text files (Unicode, ASCII, DOS/MacOS/Unix line breaks). Thanks! -- Toytoy 07:06, 21 December 2005 (UTC)

Well, this isn't a science question, but: The ultimate tool for batch-converting text files between different encodings such as Unicode and ISO-8859-1 is iconv. It's a Unix tool, and the only way I'm aware of to install it is to download Cygwin, a rather large (but free) system that gives you access to thousands of Unix tools from Windows. It almost certainly includes iconv. Another alternative appears to be http://www.iconv.com/ - which lets you convert online by uploading files. Changing line endings is relatively easy in comparison; dozens of tools can do this. Try http://versiontracker.com/ or any of a dozen other Windows shareware sites for a tool that can convert between Windows, Mac, and Unix line breaks. Dmazzoni 10:34, 26 December 2005 (UTC)

Conversion for pressure to altitude[edit]

If we know the local ground floor pressure and the pressure at a certain level in a building,how do we calculate the altitude by using the pressure?Is there any practical or empirical equation to calculate the altitude precisely?

  • For situations outside, this is quite easy to do. See Atmospheric pressure and Barometric formula. I'm unsure whether these formulas hold when you apply them to interiors of buildings. - Mgm|(talk) 08:57, 21 December 2005 (UTC)
    • The obvious answer is 'yes they do, if all the windows are open'. If it's a closed environment, then things are different, and probably depends on what setting the air conditioning happens to be on that day. Proto t c 09:55, 21 December 2005 (UTC)
Note that this method isn't terribly accurate, as local pressure variations due to winds, solar heating, etc. could throw off the results. This method is fine for airplanes, which only need to stay at a certain altitude with a + or -500 foot variation, but there are other far more accurate ways to measure the height of various floors in a building. StuRat 01:50, 22 December 2005 (UTC)
In one episode of rough science, someone measured the size of a mountain fairly accurately by measuring the air pressure at the foot and then at the top. This would of course have to be done with as small a time interval as possible to avoid the influence of any change in weather. But we're talking about quite a height difference here, so, as with the airplanes, any deviations will be relatively less important than with the height of a building. Also, with a building you have to take care that the inside conditions are the same as outside, and heating might increase it. And in a previous question I pointed out that if any openings are only on the windward side that will increase the air pressure (and even more so vice versa because the any wind might suck out air). DirkvdM 13:38, 23 December 2005 (UTC)

Converting Word document to PDF[edit]

Hi. I am trying to convert a word document to a pdf. I can get it working with a normal white background. However, when I tried adding a background effect and converting, the background effect is lost on the pdf, in otherwords the pdf still has the normal white background. Does anyone know how to fix this? I am using Word 2003, and PDF Maker 7. Thanks. - Akamad 10:17, 21 December 2005 (UTC)

As far as I know, the Background Effects in Word only works in the Online View. In my version anyway, if you apply a background colour or texture, the view changes to Online View, and if you change it back to Normal View, the effect disappears. The only way to save the file as a PDF is to save the file as an HTML document (File > Save as Web Page), open the result in Internet Explorer or another browser, and then print the "web page" to the PDF Maker. I think you'll be pleasantly disappointed with the results, it looks awful, but that's Microsoft for you... --Canley 12:01, 21 December 2005 (UTC)
In that case you could try this. Instead of adding a background effect, draw a rectangle over the whole page and add a background image or fill effect to it. Format the rectangle as "behind the text" So that you can read the document then convert to pdf - it might work. Theresa Knott | Taste the Korn 16:36, 21 December 2005 (UTC)
You could also have a try at opening the document in OpenOffice and saving it directly as a pdf. If you don't have any wacky formatting, it might be easier. - Taxman Talk 18:25, 21 December 2005 (UTC)
Thanks all for your responses. The method I ended up using was similar to Theresa Knott. Except I didn't know how to fill in a rectangle with a background effect. So I created a blank page with the effect, print screened it, and copy and pasted it in from paint. Once again, thanks. - User:Akamad Merry Christmas to all! 07:10, 22 December 2005 (UTC)

artificial flavors[edit]

are the artificial flavors added in food items like potato chips harmful to our health?if so how?thanks

That depends on how you define "harmful". Cigarettes are sold to millions (billions?) of people every day and they are considered harmful. Many countries have a governing organization that determines what companies can put into food products. In the United States this is handled by the United States Food and Drug Administration. Also see Food coloring. Dismas|(talk) 13:16, 21 December 2005 (UTC)
It's unknown; some people can develop nasty allergies to flavours/colours such as Tartrazine, Monosodium Glutamate and Aspartame, and no-one knows whether these also affect healthy people. Ironically, the healthier foods, notably 'diet' drinks, can be highest in these chemicals (Aspartame is common replacement for sugar). As to crisps/potato chips however, I'm not sure. smurrayinchester(User), (Ho Ho Ho!) 14:11, 21 December 2005 (UTC)
This is a topic of hot controversey between folks like the Food and Drug Administration (and, at the risk of sounding biased, nearly all mainstream scientists) on the one hand and various health food advocates and others on the other. Some of our articles, like that on MSG, talk about the controversey. If you're really worried, I'd talk to a local nutritionist; be very wary of what you find on the web, as a lot of the information is put out by people who want to sell (ostensibly) healthier products. --George
If you are concerned, one option is to use foods with natural flavorings. Many people prefer the taste, anyway. Some artificial flavors, like artificial grape, are nothing like the real flavor, while others, like artificial banana, are quite close. The main reason for artificial flavors is that they are cheaper. However, food is so inexpensive these days relative to it's historic cost that the extra money spent on natural flavors isn't a very significant portion of most families' income these days. StuRat 01:44, 22 December 2005 (UTC)
You might want to have a look at E number. That's quite an impressive list and most additives are linked, so look up anything that's in the food you eat if there are any warnings about them. That is, if you're from Europe. Elsewhere, I don't know how it works, but you might also look at List of food additives. And to add to the open door that Dismas kicked in. Cars are sold by the billions and have so far killed 25 million people. That's world war scale. And that's not counting the effect of bad air, which one inhales day and night with every breath one takes. I'm not saying you're barking up the wrong tree here, just that there are many more trees and some might be dropping on you much harder (so to say...). :) DirkvdM 13:50, 23 December 2005 (UTC)

Arthritis[edit]

Hello, I am a student in PA who is currently trying to determine for a paper whether or not arthritis can be caused or helped along by the cracking of knuckles and such during adolescence and younger years. I understand that not all types of arthritis are subject to this kind of damage. I was just wondering if there were any articles that could be sent to me in a link that may help me along. I have been researching this for quite some time and there are so many differing opinions that it is hard to conclude. And since I do not have the resources to conduct an in depth experiment, I am having a difficult time making my paper solid. I believe myself that it is helped along and caused by the cracking of knuckles and cartilage intentionally when younger. However, there are scientists who both agree with me completely or they are completely against the idea and believe it to be preposterous. Any help would be much appreciated! Thank you!--- Chloe

If I may offer an anecdotal observation.
  • In my life, I have only observed a subset of adolescent boys who engage in the knuckle cracking pastime. Perhaps some survey could be conducted to find out what proportion of populations admit to having done this at all, and how heavily.
  • Seems to me, arthritis hits men and women equally heavily. I imagine there may be medical statistics out there on proportions of population suffering at what ages.
    • Acording to the Wiki article "the disease affects about twice as many women as men". This would lead me to suspect that there may be a relationship with how much milk (calcium) is consumed early in life, since women are susceptible to that bone disease that leads to elderly shoulder problems in later years.

User:AlMac|(talk) 15:25, 21 December 2005 (UTC)

It sounds like you already have found some papers on the topic. Use the references in those papers, and if they are not recent, ask a medical or university librarian (like at a local hospital or university) to help you find more recent papers that have cited the papers you already found. alteripse 00:34, 22 December 2005 (UTC)

Kerberos on pen-and-paper[edit]

Is there any Kerberos-like (mutual password-less authentication) protocol that can be used with pen and paper, to provide a basic level of security? —Masatran 13:42, 21 December 2005 (UTC)

Pretty much any computer security protocol can be implemented with pen and paper using postal mail as a very slow (in comparison to computer networks) transport mechanism. For something practical, that real people could use, you should probably think about what kind of security you're interested in (authentication, protection against eavesdropping, ...). -- Rick Block (talk) 17:12, 21 December 2005 (UTC)
I am looking for a Kerberos-like protocol in which:
  1. Computations can be completed in a few minutes on pen and paper
  2. The process can be completed in a few minutes over telephone
Masatran 11:04, 26 December 2005 (UTC)

Banging Bolts[edit]

Our new office building is driving us nuts with banging bolts [49]

I only could find a couple of references, but as an engineer I found that there were different ideas on how to prevent it. This would be important for psychiatric hospitals! Is it worth doing an article? Does anybody have any more info? --Zeizmic 17:16, 21 December 2005 (UTC)

Even a short article with that covers the points in the source you provided would be a good thing. I'd never heard of banging bolts but was very interested to read about it. -User:Lommer | talk 18:29, 21 December 2005 (UTC)
I put up the article bolt banging. Perhaps, it can comfort people :) --Zeizmic 22:39, 21 December 2005 (UTC)
Our article mentions that it's not agreed how to eliminate the problem. Aren't friction grip bolts an effective alternative, or is the cost to high? For a hostpital the added deflection performance could be handy.--Commander Keane 03:03, 22 December 2005 (UTC)
One obvious solution is to leave the building unoccupied for a while after it's completed. This would also allow toxins in the new carpet, new paint, new furniture, etc., to vent off before occupants must breathe them, provided these are also put into place as soon as the building is completed. If the expense of an empty building is too much, adding lubricants to the bolt threads to allow them to seat more quickly and quietly might be in order. Some type of oil, which would eventually evaporate and make the bolts "tighter" would be preferable to a graphite lubricant which would leave them loose forever. StuRat 07:20, 22 December 2005 (UTC)
I really believe this could be the beginning of an adverse trend. Maybe the article could invoke some research, such as a civil lab setup, or post-construction seismic monitoring. I agree that some small modification on the bolts (teflon?) could be the answer. --Zeizmic 12:57, 22 December 2005 (UTC)
I would think Teflon, like graphite, would leave the bolts permanently loose as a result of the reduced friction, allowing them to potentially vibrate off over time. StuRat 01:40, 23 December 2005 (UTC)

Few questions about CRT monitors[edit]

How bad is a CRT monitor for our eyes and our health? Should we avoid CRTs or is it not that bad? What kind of trouble does that exactly give to our eyes and our health generally? Does keeping our eyes closer to CRTs create more problems than seeing from normal distance? Is there any time limit per day we may follow for being before a CRTs?

Sounds like a Homework question to me. See CRT

A lot of the effect of CRTs on eyes is unknown. These questions may never be fully answered, as CRTs are rapidly becoming obsolete, being one of the few remaining vacuum tube technologies. I suspect that in another decade they will have been fully replaced by LCD and plasma flat screen technology. The only thing preventing a quicker change is the cost of the newer technologies, but those will drop rapidly with mass production. StuRat 01:30, 22 December 2005 (UTC)
Many people have some legitimate ergonomics concerns, like is heavy mouse use (like in computer game playing) more likely to cause carpal tunnel syndrome at a younger age? I work in the profession of lots of people in business sitting most of day in front of work stations, and I have looked into some health issues. I agree that over time this is a moving target.
  • Do you have fluorescent lights in the ceiling? Many offices have that. The direction of the lamps in the ceiling relative to the placement of the monitors can have a mutual flicker rate interference that is bad on the eyes ... you better off sitting where those lights are from front to back relative to direction you sitting, not side to side, and not directly overhead, but to your sides, overhead. I not have comparable data on other kinds of lighting such as halogen, but at home I use hallogen pointed up to bounce off white ceiling, so the light is diffused.
  • Do you have to wear glasses, or other vision correction? Did you know that just as your glasses cam be set to be the right length when driving, or reading, or whatever, they can also be set for the optimal distance your eyes from the screen?
  • There is a science to color contrasts. It is no coincidence that the Telephone Directory uses Yellow Pages (black print on yellow background). Scientific study has shown that, all other things being equal, the easiest on the eyes is black print on yellow background. But this also depends on other stuff around. What color are the walls around the computer monitor you use? Because of this, at home I have a white background text monitor, when I using monochrome stuff (you can manipulate this on your computer settings), and I have light colored walls bahind, above, around my monitor.
  • Are you working at a "computer desk?" Traditional desks are designed to be comfortable altitude for you to work with papers and writing on them, but keyboard is somewhat elevated above that, so "computer desks" deliberately have lowered placement for the keyboard, so no strain on user.
  • Is your seating comfortable to see the screen and use the keyboard, and get at other papers, or do you end up working hunched over?

User:AlMac|(talk) 09:47, 22 December 2005 (UTC)

SI units and light[edit]

Would it be feasible to use SI units when working with the constant speed of light? For example, one µc (micro c) would be about 300 m/s (~670 mph). An nc (nano c) is about 30 cm/s. Zhatt 18:43, 21 December 2005 (UTC)

Not really. For one, the units are meter and the like, not the prefixes you're mentioning. For two, c is not itself a unit (to which such prefixes are generally applied) but rather a constant rate. For three, the prefix doesn't have any real meaning that I can see when applied to a rate -- what, exactly, is a "nano c"? c/(10^9) lacks this ambiguity. While examples like Kbps exist, it's debateable whether it's K(bps) or (Kb)ps, and the clear physical meaning is present either way. — Lomn | Talk / RfC 19:03, 21 December 2005 (UTC)
What's the difference between K(bps) or (Kb)ps? I mean, I understand the difference in grouping, but why does it matter—is there any physical or other significance? — Knowledge Seeker 22:59, 21 December 2005 (UTC)
None. It's a distinction without a difference. Raul654 23:03, 21 December 2005 (UTC)
Oh, yeah, sorry. I meant SI prefix. Zhatt 19:05, 21 December 2005 (UTC)
I don't see how µc (or, for that matter, kb/s) would be any more "ambiguous" than perfectly ordinary prefixed speed units line, say, km/h. Certainly you can parse that as either k(m/h) or (km)/h, but it's the same unit either way. SI prefixes are applied to derived units, including units of speed, all the time. Applying them to nonstandard units like c is no more silly than using units such as attoparsecs. —Ilmari Karonen (talk) 19:13, 21 December 2005 (UTC)
I'll cite from your linked article: bits of dry humor combined with putative practical convenience. If that's a rationale for feasibility, then by all means, proceed. — Lomn | Talk / RfC 19:48, 21 December 2005 (UTC)
I can see it having some practical convenience. When talking about astrophysics and the like, I offten hear the phrase a fraction of c come up. Instead of saying zero-point-zero-zero-one cee, or a thousandth of a cee why not just say mili-cee? Zhatt 20:05, 21 December 2005 (UTC)
I think I erred in using "rate" as the example when I referred to c as a "constant rate"; my personal objection derives from c as a constant. I find the thought of a decapi equally silly, despite the fact that such a number does exist and could be referred to. — Lomn | Talk / RfC 22:03, 21 December 2005 (UTC)
It's not like you can't take a multiple of a rate, I mean you could take a µδ(fn)/δt (a 'micro' derivative if you will) but all you'd be doing is multiplying an ordinary differential, by a constant µ, hence µ x δ(fn)/δt, which is, kind of silly--Aolanonawanabe 22:12, 21 December 2005 (UTC)

I've been thinking about this for a while and I wasn't really convinced by the explanations above. I'd have to say that there is no inherent reason that one couldn't combine a prefix with a rate and so on. I think Lomn is on to something: we think of c as a constant and it does seem odd to use the prefix. The π example is telling as well. You're right that since we often specify speeds that are fractions of the speed of light, the prefixes might be useful. But even if there were some geometric situation in which one-tenth of π were used frequently, I'd probably still want to use 0.1π rather than dπ. It somehow feels different with constants or measurements compared to units of measurement. But I think the main obstacle for me, surprisingly, is pronunciation. Perhaps it's just the way I think, but when I see "5.5 mm" I hear "millimeter" in my head, not "em em". I hear "microliter" instead of "mu ell" (although I've occasionally said "kay gee" for "kilogram". But the point is, I wouldn't know how to read μc. Certainly not "mu see". "Micro see"? "See" is the name of the symbol, not the unit. And of course "micro the speed of light" is ridiculous. I'd probably read it as "one hundredth the speed of light" or "point one see" and therefore I write it "0.1c". Now if a unit of velocity were defined such that one unit was equal to c, the speed of light in a vacuum, that would be a different story. The distinction is subtle, but significant. For instance, regarding the atomic mass unit, written "amu" or now "u", I would never think to write "k·amu" or "ku" even if the abbreviation "u" for "atomic mass unit" were more prevalent. However, I routinely use "kDa" (kilodaltons), where one dalton is equal to one mass unit. Not sure if this helps, but this I think is why the idea doesn't sit well with me. — Knowledge Seeker 10:29, 22 December 2005 (UTC)

I understand now. At the start I thought that c or constant would be a bad term to use. Like you said, we need to somehow make up a unit for the speed of light in a vacuum. lv? Two µlv = 599.6 m/s? Needs work, but thanks. Zhatt 18:34, 22 December 2005 (UTC)

It's perfectly acceptable to have a unit defined in terms of a constant. That is, after all, what a light year is. Astronauts frequently speak of milli-g gravity, which means one one thousandth of the constant g. No reason why one couldn't also speak of µc, millionths of the speed of light. -lethe talk 21:51, 22 December 2005 (UTC)

How much do celestial objects affect gravity on earth?[edit]

Because we have the moon, sun, and planets, each with their own gravity, and these objects move in relation to the earth, one would expect "down" as given by a plumb bob to vary. How much does this "down" vary? One would also expect the weight of an object with given mass (but kept in a constant location on earth) to vary. How much would it vary? --Juuitchan

You have just described tides. —Keenan Pepper 20:25, 21 December 2005 (UTC)
The effect is quite minimal, and is only obvious in the case of tides because the total amount of water in the oceans is so vast. It's like we are zoomed in on the very top of a bar graph which has a microscopic sinusoidal change in height. Other forces which affect little g, the acceleration due to gravitiy on Earth, (such as the elevation, centripetal force, and local vari