Wikipedia:Reference desk archive/Science/October 2005

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Greatest Common Factor / Least Common Multiple Problem[edit]

I recently went to a math competition and this problem is bugging the heck out of me. Can anyone show how to solve it as well as provide the useful laws?

Q) A positive integer 'n' has the property that the least common multiple of n and 36 is 500 greater than the greatest common factor of n and 36. What is 'n'? Written mathematically: LCM(36,n) - 500 = GCF(36,n)... n=?

Thanks C. Nelson 22:26, 2 October 2005 (UTC)

Earliest Fossil Egg[edit]

Where was the earliest fossil egg found?

-anon

As yet, we do not have an article on Fossil eggs nor does our fossil article provide much detail. However, these articles by The San Francisco Chronicle on dinosaur fossil eggs [1] and the National Geographic on bird fossil eggs [2] should be of some assistance to you. I have added Fossil eggs to Wikipedia:Requested Articles so that someone can write an article on this topic. Capitalistroadster 00:08, 23 September 2005 (UTC)

which part of the tree contains live wood?[edit]

  • Depends on the tree, but potentially all of it. -- Jmabel | Talk 05:34, 23 September 2005 (UTC)
    • Well, it does depend on the tree, but most "normal" trees (not, for example, palm trees) have living cells in the outer sections of their trunks (except the bark) and dead cells in the interior and the bark.

      Details: There is a thin, roughly cylindrical shell called the vascular cambium, which is where a tree does its growing. The outside of the cambium produces new phloem cells, which do "food" transport. The inside of the cambium produces new xylem cells, which do water & nutrient transport from the roots. Old phloem gets shed with the bark, but old xylem just sticks around, forming a core made of dead cells that provides structural support to the tree. Most trees add a new layer of xylem each year. The old dead xylem layers are the rings one can see on a stump.

      It appears to little-old-nonexpert-me that this ability to make a single, strong core out of dead xylem is probably one of the main factors that allows trees to grow so tall. Lots of plants have this phloem/cambium/xylem structure, but in many of the smaller ones, the cambium does not form a single large cylinder, but rather many small ones (vascular bundles). Thus, the xylem is scattered and strength is lost. I imagine this is one reason you will never see (say) a celery tree. On the other hand, the multiple bundles probably allow for faster growth ("growing like a weed"). Interestingly, palm trees have the multiple vascular bundles, but can still form large, strong trunks.

      Much of this is hinted at in our tree and xylem articles, but never quite stated. Maybe it should be.

      Nowhither 00:14, 24 September 2005 (UTC)

Any Airsofters in the LA county area?[edit]

Any Airsofters in the LA county area?

Oh Jesus Christ. Is the concept of the Reference Desk that dense and foreign to some people? Garrett Albright 12:21, 23 September 2005 (UTC)
That's a valid question, just not the kind you want to answer. Superm401 | Talk 13:44, 23 September 2005 (UTC)
  • It's an easy question to answer, and perfectly valid. Given the huge population of LA, and the burgeoning popularity of Airsoft, the answer is indubitably, "Yes". --jpgordon∇∆∇∆ 14:38, 23 September 2005 (UTC)
  • Okay, please do not bite the newcomers. To the original poster: The answer is "yes", there are airsoft players in that area. Perhaps you are one of them. However, that is obvious. I would guess that your real reason for posting here is to meet airsoft players (?). If so, then you are in the wrong place. The Wikipedia Reference desk is for answering factual questions, not for meeting people. A quick Google search turns up many airsoft-oriented websites. I suggest you try one of them. — Nowhither 00:20, 24 September 2005 (UTC)

Electron - Proton[edit]

What we have been taught is that electron revolves around a proton because of electromagnetic force of attraction. But this force is same for both the electron and proton. This is when we neglect other forces like Gravitation since it is only 1/100 th times of electromagnetic force acting. Then why do electrons revolve around the protons instead protons can move around an electron??

Yes, the force on the two is the same (in accord with Newton's third). However, the proton is 2000 times more massive that the electron, so it remains relatively stationary. Just like the Earth orbiting the Sun, both objects actually orbit the center of mass, but the center of mass is closer to the more massive body. In both cases, the more massive body is so much more massive, that you can often neglect the massive body's revolution. -Lethe | Talk 02:24, 23 September 2005 (UTC)
Isn't it a bit 'oldfashioned' to think of an electron evolving around the nucleus? This is 'particle-thinking', but elementary particles can also be seen as waves. I envision electrons and other 'particles' as sort of pulsating three-dimensional waves. Lomn mentions in 'Volume of the proton' above, that the position of electrons can only be expressed in probablistic terms. If the electron can als be seen as revolving around the nucleus then I can only rhyme all this together by seeing the electron as occupying the same space (on average) as the nucleus, just covering a wider area. So the amplitude of the wave would have to be (much) bigger. If I'm talking gibberish feel free point that out to me :) . DirkvdM 14:00, 23 September 2005 (UTC)
When one starts discussing particles as small as this, the distinction between particle and wave mechanics gets blurred, since both properties can be present when quantum effects present themselves. Discussing it in probablistic terms is one way of expressing it, but there is a mode of thought that a paricle really occupies a 'quantum area' of space and exists everywhere in that space simultaneously, whereas probablistic theory suggests it has a chance of being at an point based upon a formula.
It is a bit "old-fashioned", yes, but it is not too far from the truth. "Electrons evolve around a positively-charged nucleus, to which the are attracted by Coulombic (electrostatic) forces" is a correct statement: they just don't obey Kepler's laws... Physchim62 14:32, 23 September 2005 (UTC)


It is old-fashioned (which doesn't stop almost every physics student from doing the calculation at some point), but the principle still applies. When treating the proton and electron as a two-body problem, you can reduce it to a one-body problem with a reduced mass orbiting about the center of mass. Since the electron is so much smaller than the proton, the reduced mass is basically the electron mass, and the center of mass is basically the proton position, so you're basically solving a problem with a stationary proton.
When you actually treat the situation quantum mechanically, it turns out that you can make the same transforms (it's the same potential afterall), and you end up solving a quantum mechanical problem of a reduced mass in a symmetric potential about the center of mass. So although the result is different, you can make some of the same conclusions: that the proton is relatively unaffected and that the solutions for the wavefunction of the reduced mass will basically be the wavefunction (orbitals) of the electron. There's more information at hydrogen atom and hydrogen-like atom. — Laura Scudder | Talk 14:32, 23 September 2005 (UTC)

Wintergreen LifeSavers[edit]

Why do wintergreen lifesavers "spark" when chewed? ---12.37.12.134 --12.37.12.134 02:29, 23 September 2005 (UTC)

It appears to be a form of triboluminescence. This seems a useful explanation.-gadfium 03:40, 23 September 2005 (UTC)

The American roulette?[edit]

If two persons both eat the same amount of beef each and every day from the same large pool of cattles, which person is more likely to get mad cow disease in the long run?

  1. Mr. A: Eat hamburgers made from grinding and mixing many many many cattles' meat.
  2. Mr. B: Buy a frozen cattle carcass each time and eat the dead body from head to tail.

I guess Mr. A's risk is much higher than Mr. B's. But could it be possible that by mixing a few thousand dead cattle's meat at a time, the concentration of bad prion would become too low to be threatening? -- Toytoy 03:38, 23 September 2005 (UTC)

In the UK, it's thought those who got vCJD generally got it through hamburgers and the like. Bad slaughtering practices are much more problematic when you don't do it yourself and then mince the remains to cover any mistakes... Shimgray 11:56, 23 September 2005 (UTC)
I would agree that it's Mr. A because the smallest piece of meat you can realistically grind is still probably large enough to contain millions of prions. Superm401 | Talk 13:41, 23 September 2005 (UTC)
OK, I know you can't use meat puree to make a good hamburger. A piece of hamburger, in theory, may only have hundreds of cattles' meat in it. Then how about sausages such as hot dogs? These products are manufactured in very big factorie (lots of cattles), the meat is pulverized and then thoroughly mixed. Does it make franks more dangerous than hamburgers? -- Toytoy 14:05, 23 September 2005 (UTC)
More cows means more dilution, so the amount of germs you ingest may be below some threshold. I've heard that in order to get malaria you have to get bitten by an infected mosquito several times (don't know how many and over what period of time). Mad cow disease might be completely different though. Just a consideration. DirkvdM 14:20, 23 September 2005 (UTC)
Look again at what I said above. A grinder(not blender) probably outputs shreds of meat that are maybe about, say, half a gram. I don't know how many prions could fit in that, but I'm pretty sure it's 100s of 1000s. I think that's enough to infect you. Then again, I could be wrong. But there's my argument. Superm401 | Talk 20:48, 23 September 2005 (UTC)
Difficult to say, because we don't know the level of infectiousness of the prion involved, but my feeling would be that route A is more hazardous (for the reasons discussed above). Physchim62 14:37, 23 September 2005 (UTC)
  1. 1 is eating many many cattle over a long period of time. #2 is eating one cattle over a long period of time. Assuming every cow you eat has an equal chance of having bad prions in it (big, artificial assumption), it would seem that #1 would be more statistically more hazardous. --Fastfission 22:51, 23 September 2005 (UTC)

I guess it is still unknow how much prion would cause one to be infected. If we hire many vegetarians and feed them infected meat and wait a decade, we may learn what are the minimum prion concentrations to infect 10%, 20%, ... 50%, ... 90% and 100% of people after consumption of a portion of beef. But we simply cannot try this on people ... at least to vegitarians.

Had anyone tried this on animals? -- Toytoy 00:40, 24 September 2005 (UTC)

To bring a bit of perspective to the whole "mad cow" panic, it's worth remembering that in the 20-or-so years since BSE became apparent, fewer than 160 humans have died in the entire world from nvCJD. Eating lots of hamburgers is vastly more likely to kill you from heart disease than CJD. -- Arwel 13:24, 24 September 2005 (UTC)

Very possibly, many cases were not diagnosed, some of them are still hidden, but the actual numbers may still be a very low number in comparison of other kinds of deadly food poisoning or long term health hazards (tran fat, salt, cholesterol ... problems).
I guess it is because this disease has a very low rate of transmission among animals and humans. A cow eating dead cows has a very low chance to get the disease. A man eating infected cows also does not ge it most of the times. However the rate is not that low to make this disease a non-issue.
I also wonder if dilution plays a part in lowering the rate of infection. Are hamburgers more dangerous than steaks? Are hot dogs even more dangerous? Shall we restrict or increase the size of the batc during meat processing if mad cow is the only concern?
If a tiny itsy bitsy piece of meat is infectious, then an infected cow broken apart into a million pieces may infect hundres if not thousands people. If that itsy bitsy piece of meat is not infectious, then possibly no one gets mad cow because of it. -- Toytoy 14:54, 24 September 2005 (UTC)
Read the article on prions. Even one madcow prion can infect a human. Since this prion predominantly affects the central nervous system, the risk of the two persons would depend on how the animal(s) is/are slaughtered. If care is taken to avoid knifing the CNS's (most infectious part) of the mass-load of cows, but not the one .... Besides, cooking the meat to the point of denaturing the prion would nullify the risk. Mad cow has been around forever under the name "Creutzfeldt-Jakob disease" and you probably have as good a chance of catching it from one of those few people as you do from the cow meat.

Oil[edit]

For some reason, my face is always oily, why does this happen and is there a way of preventing it from happening?

Thanks, Tasha

The simple answer is that skin oils help protect your body against attack by microorganisms. Excess production can be due to many factors that vary greatly from person to person, including, but not limited to, diet, exercise, climate, medical conditions, and ethnicity. I think it would be a good idea to talk about this with your family doctor, who is more knowledgeable about your circumstances than we are.--inks 06:56, 23 September 2005 (UTC)

What is evolution?[edit]

See evolution. - Fredrik | talk 04:59, 23 September 2005 (UTC)

Bermuda Triangle[edit]

What is Bermuda Triangle?

branded product marketing[edit]

(no question asked)

Did you have a question? — Nowhither 00:24, 24 September 2005 (UTC)
Start with category:brands. -- Ancheta Wis 23:07, 1 October 2005 (UTC)

Quarks[edit]

Are there important differences between atomic nuclei and quark matter such as quark-gluon plasma? How can it be experimentally determined that a nucleus is composed of distinct nucleons? ᓛᖁ♀ 05:33, 23 September 2005 (UTC)

australian native animals[edit]

where is the emu found in australia?

Throughout most of it. See [3]--inks 06:46, 23 September 2005 (UTC)
Or you could try our article on emus, which has a picture representing their range. --Robert Merkel
Although generally not in metropolitan areas, I've never seen an emu near the city, so generally rural areas on the map at emu. --Commander Keane 10:50, 23 September 2005 (UTC)

Why does wind gust?[edit]

I know that wind is caused by air movements from areas of different pressure - and the closer these areas of different pressure are to each other the stronger the wind it. I also think I know that its the rotation of the earth that stops it all evening out into one average pressure area. I don't understand though why the windspeeds are not constant but they gust - sometimes much more than others? Thryduulf 08:10, 23 September 2005 (UTC)

Because pressures are not a constant, even in a given location at a particular time of year. Chaotic variations in temperature and water vapor concentrations mean pressures are always changing as well. This in turn results in varying windspeeds. Superm401 | Talk 13:35, 23 September 2005 (UTC)

Does it cause cancer?[edit]

My friend asked me an uncertain question concerning blood clotting (coagulation), so I got Wiki to help him solve his question, here it is: Does it cause cancer (anything cancer, like blood cancer etc) if sb had serious blood clotting?

  • Excessive blood clotting is certainly a problem, but as far as I know it doesn't cause cancer. Cancers are malignant cells with excessive growth and even they need an uninterrupted blood flow to deliver nutrients to their cells. So I would say serious coagulation is just as bad for cancers as it is for normal tissue. See Cancer and Leukemia and for more info. - 131.211.210.12 11:13, 23 September 2005 (UTC)
    • Even if excessive blood clotting -did- lead to cancer, you would not live long enough for it to grow to any significant size. You would almost certainly die of a heart attack or stroke not long after blood clots started forming in your circulatory system.--inks 12:05, 23 September 2005 (UTC)
Usually the causal relationship runs the other way—a cancer that affects the blood-forming tissue of the body (the bone marrow) leads to over- or under-proliferation of megakaryocytes–cells that turn into platelets and cause clotting–leading to clotting disorders.
Large tumours secrete chemical signals that drive angiogenesis:the formation of new blood vessels. (Without a blood supply, cells at the center of a large tumour don't receive sufficient nutrients and oxygen, and the tumour stops growing.) These new blood vessels tend to be irregularly formed and tortuous in shape; the blood flow in them is turbulent and disordered. This turbulent flow tends to encourage clot formation; those clots can be dislodged and cause trouble elsewhere in the body.
Also, there is a correlation between deep vein thrombosis or pulmonary embolism (blood clots in the deep veins of the leg and clots in the lung, respectively) and diagnosis (recent past or future) with cancer. The mechanism for this is not well understood (as far as I know) but probably has to do with clotting stimulated by inflammation of tissue around the tumour site.
So to answer your question—no, clots probably don't cause cancer. Cancer, however, can cause clots. TenOfAllTrades(talk) 13:27, 23 September 2005 (UTC)

Example tutorial of TI-92PLUS[edit]

Do anybody know about the usage of TI-92PLus?I recently given a assignment which want me to write a programme by using this calculator.If possible,please give me some examples or tutorial of the programme?Is there any websites related to the programming of this calculator too?Thanks.

I suggest you start by reading the manual, if it's anything like the one for the TI-83 Plus, you'll find plenty of examples in there. --Pidgeot (t) (c) (e) 13:42, 23 September 2005 (UTC)
I agree. The TI-83 Plus manual is excellent, I made a game on it with no other reference. Bart133 (t) 23:27, 28 September 2005 (UTC)
\offtopic Well, it's got to be better than the HP-39G+ manual. I'm trying to learn how to program this and the manual actually tells you how to use about four commands, then says "The functionality of the rest of the commands is left as an exercise to the reader". splintax (talk) 09:40, 30 September 2005 (UTC)

Help using Internet explorer[edit]

I am using Internet explorer. All these days, I used to download pages, disconnect, and view pages later. But suddenly, for the last ten days, when I close the browser windows and open it later, I cant view pages offline. It says 'page not available offline'. What should I do? I tried by going to Internet options, but after that dont know what to do. Please help.

Your cache may be filled. Try clearing it through Internet Options, as well as verifying that its settings are correct.
Alternatively, you can use Save As to save a (temporary) copy of the page to yuor harddrive so you can view it from there after you disconnect. --Pidgeot (t) (c) (e) 17:20, 23 September 2005 (UTC)
If you install another browser (and while you're at it, why not make it a better one like Mozilla, Firefox or Opera ... ) and try it with that, then at least you'll know if the fault lies with the browser or that you should look elsewhere. This is also a much more general tip. Keep an alternative handy, such as a second ('free') internet connection. DirkvdM 06:28, 24 September 2005 (UTC)
You might also wanna check you are visiting the same pages. Some script-generated pages cannot be cached by the browser.--Fangz 12:58, 26 September 2005 (UTC)
I think the questioner is using the "offline pages" functionality in IE to save a cache of pages so that they can go back and look at them later on, without connecting (presumably they're using a dial-up connection). Try clicking "Favourites", and "Add to favourites" on the website you want to cache, and then select "make available offline" and click Customize. Follow the instructions and you should get the problem sorted out. :-) splintax (talk) 04:13, 3 October 2005 (UTC)

what exactly is a buckeye[edit]

Have you checked buckeye? In the context of Ohio State, it refers to the first entry in the disambiguation. — Lomn | Talk / RfC 17:54, 23 September 2005 (UTC)

Thunder/lightening[edit]

I have read both the articles related to this subject but I'm still not sure about one thing. Can thunder occur without the presence of lightning, and visa versa. Thanks, DEE

Lightning causes thunder, so as a general rule, no and no. However, many things other than lightning can cause sounds similar to thunder (explosions, sonic booms, and so forth) and it's not always possible to observe both lightning and thunder at once. — Lomn | Talk / RfC 18:24, 23 September 2005 (UTC)
Ehm, when you observe thunder and lightning at once you might not be able to tell the tale :) . But more seriously, there are different sorts of lightning, such as Ball Lightning, which makes a crackling sound if any at all. Strangely, the lightning article doesn't mention St. Elmo's Fire (which I'll amend next), which, I imagine, won't make any sound either. By the way, my grandmother once saw a lightning ball come in through a window, hover for a bit, and go out again. Only after her death did people learn that such things really exist. The poor woman was branded a liar. No-one ever believed her. DirkvdM 06:53, 24 September 2005 (UTC)
Someone did a lecture about ball lightning in a class I had the other day, but they were fairly vague and seemed to write it off as almost pseudoscience. I'm off to check out that article - thanks for the reminder. :) splintax (talk) 09:48, 30 September 2005 (UTC)

Austim and Music Therapy[edit]

I am looking for any information on the treatment of autistic children through music therapy. Anything about it's effectiveness, methods, etc, would be incredibly helpful. I would also like to find any information disagreeing with this method. Thank you so much.

anon

  • I don't know the answer to your question, but hopefully you can find something by reading our article on autism and the list of autism-related topics. I believe there are several Wikipedians with a special personal interest in autism, so that area has received some attention. Bovlb 19:39, 23 September 2005 (UTC)

Genetic Engineered Food[edit]

Seems to me the risks far outweigh the benefits, yet USA Agribusiness is gung ho headed that way. Am I missing something, or is there a failure of government oversight of a business area that does not give good enough lip service to quality of safety?

Risks:

  • Many nations want grain, and animal products from grairi, where there was no genetic engineering. The USA is no longer able to serve those markets, because of massive contamination, and inability to police the contamination. For example, a farmer who tries to make the pure product, cannot, because contamination is freely in the winds that other farms "breathe." Thus, as genetically engineered byproducts filter down the food chain, the USA locks itself out of more global markets.
  • Today in much of South and Central America, and southern states of USA, there is a real serious problem with Killer Bees. This is a man made problem, that came about thanks to experiments in breeding a better honey producer, but the experiment had very negative consequences.
  • Once upon a time, there was Mad Sheep disease (Scrapie) caused by short cuts in managing food supply in agriculture, which spread to cattle, so then there was Mad Cow disease, then there were experiments to try to understand this using Deer in captivity, deliberately given the disease so that we had Mad Deer, but due to the experimenters not understanding how the disease could spread, the Mad Deer in captivity licked fences, which were also licked by Wild Deer at edges of the enclosures, so now Mad Deer was in the wild, and eventually spread to all of North America, which gave the disease back to animals in agriculture, such as pigs, and to the animals that eat Deer, such as mountain lions. So we are on a collision course with a worse disaster, fueled by efforts to do cost savings in agriculture, with government oversight that is driven by rear view mirror to past disasters, rather than oversight of theories about future risks.

Benefits:

  • When there is a wide range of quality of animals producing eggs milk meat, whatever, this is a breeding technique to make copies of those that are the best.
  • Genetic engineering, cloning, and Transgenetics is a real cool thing to do. Any company that announces successes will get oodles of money from venture capitalists who think there's lots more profits down the road from this.
  • Ok, we know there are major disasters down the road, but we can still make oodles of profits capitalizing on the industry that is exploring this high risk area, then hopefully get out of the business, before the disasters put them out of business.

AlMac|(talk) 22:40, 23 September 2005 (UTC)

AlMac: The question of whether using genetically modified organisms to produce food is a Good Thing is one I will leave to you and others to decide. However, you missed some of the most important entries in the "benefits" list. Most of these, in the end, deal with cost. Using GMOs we can produce food more cheaply. We do this by creating GMOs that, compared to their natural counterparts:
  • Produce more food.
  • Have greater disease resistance.
  • Mature faster.
  • Can grow in more adverse climates.
By making food more cheaply, food producers get to spend less money. Someone might say, "Yes, because they are greedy." Well, I'm greedy too. I want a lower food bill. Don't you?

It should be noted that cost reductions also have applications in combating hunger in developing nations. As does creating a GMO that produces more nutritious food than its natural counterpart.

Lastly, I'd note that at least one of your "Risks" arguments isn't quite right. "Killer bees" were not created through modern genetic engineering, but through old-fashioned interbreeding. This phenomenon has been going on for thousands of years and, in general, has been quite safe and successful. A single isolated example is not a good argument against it. And it is certainly not an argument against modern genetic engineering, since it was not used in this case.

Again, I am not arguing a position here. I just saw that your list of "risks" and "benefits" seemed awfully lop-sided. You asked whether there has been a failure of government oversight. I'd say that is quite possible.

Nowhither 00:44, 24 September 2005 (UTC)

And mad sheep, cow and deer diseases have nothing to do with genetic engineering (or am I now missing something?). Which leaves only the first risk from AlMac's list. Which is scary enough by itself. But I've heard of another one. Genetic engineering can also be used to make crops more resistant to pesticides, which means farmers may (and will) start using them more liberally, which has to have negative side-effects.
But more in general, genetic engineering is rather like a boosted form of old-fashioned interbreeding, which in turn is a boosted form of natural selection. In both cases things are left less to chance, which means developments go faster. And with interbreeding we've created a situation in which diseases can spread much faster. Whole fields of plants that are all the same means that if a disease is introduced it will spread very fast. Add to that that the plants are selected on specific traits and not others, thus possibly leaving out natural defence mechanisms we don't understand yet (and there's a whole lot we don't understand when it comes to the mechanisms in nature). The lack of biodiversity also means that if a disease spreads it will wipe out all plants. That's the result of the first boost. This second boost has a potential to go farther still, which is scary.
To come back to the original question. If all this is left entirely to private companies the risk is way too high that they won't care about the long-term effects. I'm ultimately in favour of using genetic engineering (if only for scientific research), but it has to be done with extreme care, not rushing things. And private companies are by their very nature not made of the right stuff to do this. This has to be done by governments. So yes, there's a failure of government oversight. Moreover, the governments of not just the US but in the whole world should not just restrict themselves to oversight, but completely take over the industry. We're meddling with something we don't sufficiently understand. DirkvdM 07:27, 24 September 2005 (UTC)
I see something missing from your list of benefits. It's not just more food, but we can get better food. A great example is golden rice, which is as easy to grow as normal varieties, but has more vitamin A. It was designed specifically to help areas with vitamin A shortages (like most of Africa Image:Vitamin A deficiency.PNG). I think someone who wasn't used to a full belly might disagree on whether the risks really outweighed the benefits. — Laura Scudder | Talk 08:05, 24 September 2005 (UTC)

why is the sky blue[edit]

See Diffuse sky radiation. — Nowhither 00:47, 24 September 2005 (UTC)

The short answer is one quoted from a radio commercial I've been hearing lately: "All colors have wavelenghts that are diffused by oxygen and nitrogen. Since blue has the shortest wavelength, it's diffused up to ten times more, so the human eye sees more of it than any other color." I hope I haven't broken any rules by quoting that! Btw, what the heck did that article say? I couldn't make heads or tails of it. Hermione1980 01:01, 24 September 2005 (UTC)
No you didn't break any rules. See Fair use. What that means is this: oxygen and nitrogen are the two most common substances in air. "Diffused" in this case means "scattered". Light is a form of (very rapid) vibration, waves in other words; the wavelength of light is the distance it travels in a single vibration/wave. Different wavelengths of light are seen as different colors. Red is longest (in the visible range), then orange, yellow, green, with blue/violet being the shortest. Shorter wavelengths are scattered more. That means that red and yellow light tend to pass straight through the air, while blue light tends to bounce around a little. Almost all the light in the daytime sky comes from the sun. But blue, since it bounces around, may look like it is not coming straight from the sun, but rather from many directions. Thus, the sky, away from the sun, appears blue. — Nowhither 01:17, 24 September 2005 (UTC)
See also Rayleigh scattering. TenOfAllTrades(talk) 01:26, 24 September 2005 (UTC)

-1=1[edit]

A "proof" for the idea that -1=1 was posted on your page about the imaginary number i. I have replicated it in this question for quicker reference:

-1=i*i=sqrt(-1)*sqrt(-1)=sqrt(-1*-1)=sqrt(1)=1

However, your page says that this is incorrect because square roots only work for real, positive numbers. Your page on the number -1 says that -1^2/2=-1 and sqrt(-1^2)=1 therefore 1 cannot equal -1. However, a friend of mine says that this is incorrect because sqrt(-1^2)=sqrt(-1) though -1^2=1; I have written to you in order to resolve this dispute.

Thank you for your time and patience.

I'm not sure exactly what you're intending to say here because of the way you've written the math symbols. Can you go back and put gratuitous parentheses to make clear exactly what you mean(particularly at "-1^2/2=-1"). However, I can tell you you're friends wrong in saying sqrt((-1)^2)[by the way "-1^2" means "-(1^2)" so you should have said "(-1)^2" but I knew what you meant]. sqrt((-1)^2)=sqrt(1)=1, because the inside is simplified first by order of operations. Superm401 | Talk 01:16, 24 September 2005 (UTC)
This problem can be explained in several ways. My favorite explanation is that there is no "nice" function called "sqrt" on the complex numbers. Numbers have two square roots. But a function has to have a single value. When we deal with square roots of positive real numbers, we fix this by letting "sqrt" of a positive real number be the positive square root, not the negative one. But there is no nice way to fix this problem for complex numbers in general. This is probably what was meant by the statement that "square roots only work for real, positive numbers". In particular, the problem with the "proof" above is in the third equality:

sqrt(-1)*sqrt(-1)=sqrt(-1*-1).

There is simply no way to define "sqrt" as any sort of square root function that makes this true.

As for your dispute, your friend is wrong. The statement

sqrt((-1)2) = sqrt(-1)

is false for all ways of defining "sqrt" as a square root function, since this says that sqrt(1) = sqrt(-1), while those two numbers (1 and -1) have no common square root.

The lesson to be learned from all this is that we don't get to apply supposed mathematical "rules" anywhere we want, but only where they do, in fact, apply. And rules that apply in certain special cases may not apply in general. In particular,

sqrt(a) × sqrt(b) = sqrt(a × b)

works fine when a and b are nonnegative real numbers. That's what we were all taught in school, and it is correct. However, this does not mean that this applies more generally to all pairs of complex numbers. In fact, it does not.

Nowhither 01:10, 24 September 2005 (UTC)

None of the explainations here make sense to me. The part about the square root of a real number being defined as the positive root is true. The part about no nice way to fix this for complex numbers is not true. Square roots of negative numbers are defined as mapping to the set of imaginary numbers, thus 'i' is an imaginary number equal to square root of -1. Also, i*i is defined as equal to -1 because of this.
i is indeed a square root of -1, but so is -i, and (-i)*(-i) is also -1. You can't say that i is "equal to the square root of -1", because "the square root of -1" describes two numbers that are unequal. So how do you tell them apart? You can't say "take the positive one as the square root" like you do for real numbers, because neither i nor -i is positive. (Don't let the notation deceive you; remember that i and -i are perpendicular to being positive or negative.) RSpeer 05:17, 25 September 2005 (UTC)
  • Look at it this way. In school we were taught that the rule "sqrt(a) × sqrt(b) = sqrt(a × b)" is correct for all positive real numbers. Maybe you missed the "positive real numbers" part, but, I can assure you, it was (or should have been) mentioned. Now, does this rule apply to complex numbers in general? No, as the original problem in this thread shows. It may seem intuitively true to you that this rule applies to anything with a square root. However, in mathematics, we do not base our notions of truth on intuition; we prove them to be true. Many properties of the complex numbers seem non-intuitive to people familiar only with the real numbers. This is perhaps one of them.

    And, regardless of whether it seems right, it is true that there is no nice way to define a square root function on all complex numbers. If you want to be formal, then substitute "continuous" for "nice".

    Nowhither 17:47, 26 September 2005 (UTC)

5ht receptors[edit]

(no question asked)

Did you have a question? — Nowhither 01:11, 24 September 2005 (UTC)

Please review our article on Serotonin, and ask again if you need more detail.-gadfium 03:04, 24 September 2005 (UTC)

Codec hell[edit]

Well, I just got my computer and was trying to open a few video files, so I downloaded some codec packs. The first was ACE mega codec pack. It was great, opened tons of stuff, except this one divx video with some interleaving problem... Well, I removed ACE, and got a few other codec packs from free-codecs.com (k-like, xp and all in 1).

Installed all in 1 first. Didn't work. Uinstalled it. Installed XP. Didn't work. Uninstalled. Insalled k-like. It worked. But now WMP won't open the most basic video files (wmvs), and the automatic download of codecs feature returns an error (no appropriate codec could be found).

So, this sucks. Not even half of my videos are opening right now and I was wondering what I should do. Is there any tool that lets me remove ALL codecs from my computer, so I can get them all again? Is there any immediate problem on not having any codecs installed? Help! Kieff | Talk 01:30, 24 September 2005 (UTC)

Can't help with codec removal, but if you just want to play the videos, VLC player opens just about anything, and you don't have to mess with codecs.[4]--inks 20:24, 24 September 2005 (UTC)
You may be able to uninstall and reinstall Windows Media Player, or upgrade to a newer version, which will fix the codec problems. Rob Church Talk | Desk 21:14, 25 September 2005 (UTC)
Whilst I'm happy to recommend VLC player myself having used it these past couple of days, it doesn't seem to open the .wmv files I have.
Well, I managed to uninstall WMP and reinstall it. Things seem to be working now, thanks everyone. I'll avoid codec packs after this incident. Kieff | Talk 19:33, 26 September 2005 (UTC)

APPLICATIONS OF GRAPH THEORY TO COMPUTER SCIENCE[edit]

Sir,

Can you get me any three applications of graph theory to computer science" and what way it is used and details about that. Thank you. --anon. Question reformatted by Robert Merkel 08:53, 24 September 2005 (UTC)

Well, actually, I can, but I've done enough homework for one lifetime. Have you considered reading our article on graph theory, or perhaps your textbook? By the way, DON'T USE ALL CAPITALS BECAUSE IT'S INTERPRETED AS YELLING!--Robert Merkel 08:53, 24 September 2005 (UTC)

How temperature affect the atmosphere pressure?[edit]

Can you tell me how temperature affect the atmosphere pressure at an area?Is there any equation uses to calculate the atmosphere pressure of a place which related to the change in temperature?

Alternative to the Big Bang theory[edit]

I've long had an alternative to the Big Bang theory, which surfaced when I gave an answer to Wikipedia:Reference_desk/Science#A_Variable_Speed_of_Light hereabove. I'm very much a layman when it comes to this field, but I made a prediction that went against the accepted theories but turned out to be correct, which is a bit of a theoretician's wet dream :) . So I now venture to put this theory before you. Here goes.

As a kid I heard the expanding universe explained as a balloon with dots on it. On that everything moves away from everything else, which is exactly what we observe in the universe. But then I wondered, how do you know a balloon expands? My thought was that you know that because the only alternative is that the room you're in (and everything else) is getting smaller. Which would be silly. The simplest solution is held to be true, which is that the balloon expands. But for the universe there are (by definition) no surroundings to compare with. There is no reference frame, so one has to assume the size of of the universe is given. I couldn't think of a solution then.

But later I realised that you can also compare the sizes of the universe and everything in it. If the size of the universe is given then the stars and such must be getting smaller. Hmmm, stuck again.

Later still I imagined falling into a black hole. I was supposed to get stretched out. But that's seen from the framework of an outside observer. For me, I'm part of the spatial framework that gets expanded. Also, time gets ever slower form the perspective of the outside obeserver, but, again, I live in that timeframe, so from my perspective it will take me forever to fall into the black hole. So for me nothing changes (right?). Except that I see everything around me moving away from me. Hold on, I thought, couldn't that explain the aforementioned phenomenon? What if we are caught in a collapsing (part of the) universe? But then I realised that as things are further away they will accelerate away ever faster. And acceleration is not what happened, right? Stuck again.

Until a few years ago someone (Riess or Perlmutter?) discovered that exactly that is the case. When I heard of this I jumped out of my chair. After the initial enthusiasm I didn't know how to present this idea. No-one would take me seriously. Now, finally, I've found a place where knowledgeable people might be bothered to hear me out. So. Any thoughts on this?

By the way, I don't necessarily suggest we're falling into a black hole. I suppose being attracted to anything sizeable enough will have a similar effect. And since everything is attracted to everything else there might not have to be anything special going on. Though if it's that simple I find it unlikely no-one will have thought of this before. Or have they?

Also, as for the other two bases for the Big Bang theory, I don't have an explanation for the background radiation. The abundance of light elements suggests a fairly 'young' universe, which would still be possible if we're in the middle of the Big Crunch. DirkvdM 09:26, 24 September 2005 (UTC)

Hi DirkvdM. I know a reasonable amount of physics and will try to give a few comments. If we were in a collapsing part of the universe, then nearby galaxies would be moving toward us. This is only true of the Andromeda galaxy, and that is accounted for by the attraction of ordinary gravity. Everything else is moving away.
If we were falling into a region of extremely strong gravity, black hole or otherwise, that would be more clear from nearby conditions than from faraway objects.
It is also important to understand what is involved in the expansion of the universe. It is the actual expansion of the "fabric of space", rather than simply objects moving away through ordinary static flat space.
Let me know if that helps at all; I'm happy to discuss further here or on User_talk:SCZenz. -- SCZenz 22:07, 29 September 2005 (UTC)
Yes, everything moves together when moving towards a common attractor (such as a black hole or 'everything itself' so to say - the Big Crunch idea). But that is from the perspective of an outside observer who doesn't take the distortion of the space/time fabric into account. But for those inside, space is stretched out more than that (the 'more' here is an assumption that is essential to my theory). Put differently, if I'm falling into the black hole (or whatever) I accelerate towards it. Anything that's ahead of me will have gained a higher acceleration and thus move away from me from my point of view (but is that accelerated? My gut says it is :) ). Likewise, anything that's behind me will do so too, but at a lower acceleration. Sideways this is a bit more complicated, but I believe a similar reasoning applies.
You say that the effects of falling into a black hole are more noticeable nearby than for things far away. But I assumed that the distortion of space/time counterbalances the acceleration. Or rather, there is no acceleration, just the distortion. An outside observer who superimposes his local frame on my situation observes an acceleration I don't perceive.
More in general, distortion is a misconception, because that assumes an absolute reference frame, which there isn't. What I perceive as distortion is really just the difference between my local distortion and the distortion of another place I observe. So to call the time/space there distorted is really a 'lococentric' (?) pov. DirkvdM 11:55, 30 September 2005 (UTC)
I am not an expert on this stuff either. My understanding is that there are several theories on the nature of the universe. One is that it starts with the Big Bang then after expanding to some size, it slows down the expansion, because of the gravity of the parts of the universe pulling at each other, and eventually begins to collapse again. So there's a bunch of theories whether it will expand forever, if it will collapse, or if only our part of the universe is expanding. Some of this has to do with hidden mass and studies of some patterns of energy.
Have you heard of quasars (spelling?)? These are humongous point sources of energy. One theory is that we are seeing the light from the original Big Bang which bounces off the edges of the universe, less and less frequently as the edges get further away, and by studying the pattern of quazars we can map the shape of the universe.
I would prefer to think that what quazars are, are the light from intelligent travelers traveling close to the speed of light, away from us (they are red shift quazars, which is all that can be seen by observers through our atmosphere. If there was blue shift astronomical bodies, we would not see them by astronomy on the planet. If we study the heavens from telescopes in orbit, then we might see a bunch of blue shift stuff, such as an intelligent visitor headed our way. However, I not think we looking for this. Telescopes in space are looking for stuff to expand the knowledge of terresterial astronomers who are already distorted view of looking through the rose colored glasses of our atmosphere, as opposed to starting over in study of our univers. AlMac|(talk) 18:12, 29 September 2005 (UTC)
Why would the drive system of an alienship put out so much energy as to equal the light of a star? And why aren't any of them heading sideways, rather than directly away? -- SCZenz 22:07, 29 September 2005 (UTC)
When the alien ship is traveling close to the speed of light, its mass is close to infinite. This applies to the mass of all of it, including the ejecta of its propulsion system. They could be traveling in all directions. One flaw in my theorizing is the question of how long they would be blasting in some direction, relative to how long we see the red shift quazars through telescopes under our atmostphere. AlMac|(talk) 01:08, 30 September 2005 (UTC)

armed forces transport[edit]

can you please tell me where i could find information on the modes of transport the armed forces use?

Are you interested in a specific country's armed forces, or armed forces in general?
If you're interested in a specific country, you might consider going to that country's page and using the military links from there; for instance, for the United States you'll probably browse from there to the Department of Defense page and then the pages for the individual services. From each of those, you might get a list of vehicles, for instance the United States Air Force link has a link to a page called List of military aircraft of the United States.
If you're interested in this topic in general, the United States is still probably a good area to explore, as the US military has logistics capabilities unrivalled by any other military force. --Robert Merkel 10:29, 24 September 2005 (UTC)

gravitation ????[edit]

Hello:

Why is it that only one side of the moon always faces earth? If you take an apple and rotate it around a lamp you'll find of you keep the axis facing the same direction all parts of the orange will be reflected as it revolves around the lamp. But the moon has to slowly rotate in such a way that it keeps its one side visible to the earth and as far I can tell it has been showing the same side of the moon for thousands of years? This can't possibly be a coincedence, but I don't see how Newtonian laws of gravity apply to this question.

Will Sperry Kunming China

Will: It's because of tidal forces and friction.

To begin with, do you understand why the ocean has tides? The Moon pulls a bit more on the water close to it, than it does on the Earth as a whole. So there is a bulge of water on the side of the Earth nearest the Moon. Similarly, the Moon pulls harder on the Earth as a whole than on the water far from it. So the Earth gets pulled away from the farthest ocean, resulting in another bulge of water on the side of the Earth opposite the Moon. And that is why we get high tides during the full & new Moon (or nearly so; the land gets in the way of water flow, which makes it all a good deal more complex).

Now, the Earth pulls the same way on the Moon, "trying" to create a bulge on the near & far sides if the Moon. This has two effects. First, if the Moon didn't always show the same face to the Earth, then as it rotated, it would get squashed in various directions. The resulting friction would turn part of its rotational energy into heat, thus slowing its rotation (relative to the Earth). Second, if the Moon is not a perfect sphere, it would have a tendency to settle in a position in which the bulge(s) faced either toward or away from the Earth.

And that is what happened. The Moon is not a perfect sphere, tidal friction slowed it's rotation, and it settled in a position in which the bulges are aligned toward/away from the Earth.

Of course, similar logic would suggest that the Earth should always present the same face toward the Moon. Why doesn't it? First, the Earth is bigger, so it has more angular momentum to keep it going. Second, the Moon is smaller, so there is less tidal force to slow the Earth down. But if we wait long enough, and no other factors intervene, and the Moon stays in its current orbit, etc. (which won't happen), then the Earth should eventually present the same face to the Moon all the time.

Nowhither 11:21, 24 September 2005 (UTC)


Why would there be a specific bulge? (Maybe)Once upon time, millions of years ago, was the moon rotating around an axis and the earth's gravity finally slowed it down, to its current rotation? And why would friction effect the moon when it is in space where there is no friction? The tide analogy seems obvious because of the fluidity of water, but the solidity of the moon would seem to make a bulge less of a factor as the tides are effected by the moon. Over millions of years do these factors create slight changes that finally effect a final result?

Will Sperry Kunming China

Will, there is indeed friction in space; the laws of physics aren't somehow different in orbit around the earth. You're correct in that there's no air resistance (space being close enough to a vacuum for all practical purposes) but there is still internal friction within the moon. You can demonstrate friction inside solid objects be bending a paper clip back and forth until it breaks, and noting that the metal near the breaking point becomes warm. Similarly, friction within the moon's core can lower its kinetic energy. But yes, it seems plausible that the moon was at one point rotating at a different speed. --David Wahler (talk) 16:09, 24 September 2005 (UTC)
I thought this was a freak thing, caused by an uneven distribution of the matter inside the moon or a violent thing happening to the moon in its past, such as it tearing away from the Earth. The moon article states that the most accepted theory is that just that happened, caused by an impact by some third big object. However, the same section supports the above theory. But then this should also have happened to other moons. Is that the case? DirkvdM 19:04, 24 September 2005 (UTC)
DirkvdM: Yes, most of the known moons in the solar system are tidally locked. See Tidal locking. — Nowhither 19:57, 25 September 2005 (UTC)

It's called Tidal lock. The theory is, eventually every orbiting body becomes tidal locked to its parent body over time. Even the Earth to the Sun. - Cobra Ky Flag of the United States.svg (talk, contribs) 19:08, 24 September 2005 (UTC)

Drawing electrical circuits[edit]

Are there any freeware or shareware programs available for preparing diagrams of electrical circuits? I can't find any reference to them in the relevant articles. Physchim62 11:02, 24 September 2005 (UTC)

A search for "circuit" at Freshmeat.net turns up a number of packages. I haven't tried any of them myself (though I'm probably about to as an amateur PIC programmer). --Robert Merkel 12:19, 24 September 2005 (UTC)
Check this out at Wikisophia. Lots of other goodies there too which you might find useful. --HappyCamper 13:09, 24 September 2005 (UTC)
EAGLE is one I've used, which has the notable feature of being able to automatically lay out circuit boards for fabrication. (Not sure if that's something you need, but you might want to give it a look.) --David Wahler (talk) 15:57, 24 September 2005 (UTC)


There is a very good freeware called TKGate for Digital Cicuits Simulation and a very good GUI. In order to run tkgate on Windows, you will need to install Cygwin along with X11 and the X11 version of tcl/tk (as opposed to the native Windows version). For details see the Cygwin Cygwin Installation Page. As of TkGate 1.8.3, the configuration script now contains Cygwin specific code and should not require any modification.

However, for Analog Circuits, you can use Spice

Pause Break[edit]

On my QWERTY keyboard, what does the button "Pause/Break" do? --Dangherous 11:10, 24 September 2005 (UTC)

There is a brief explanation on IBM PC keyboard. These days, it's not used very much (except by gamers). --Robert Merkel 12:16, 24 September 2005 (UTC)


optical computing[edit]

What is optical computing? How does it work? What are its applications(please mention any brands or products already in use)?

Did you try reading our optical computer article? --Robert Merkel 12:09, 24 September 2005 (UTC)

md5 status?[edit]

What's the current status of the md5 hashing algorithm? There are numerous attacks noted against it, but would it be possible to easily explain what is possible and what not? And will sha-1 have the same problems soon? Thanks

Assuming you've read Md5#Practical_effect_of_cryptanalysis and find it unclear, what it's saying is that it is possible and fairly easy to construct two different inputs which result in the same MD5 hash value - however the currently known methods for doing this do not generalize to finding a second input that results in the same hash value as an arbitrary given first input. MD5 is often used as a checksum to "guarantee" the validity of downloadable software files. This weakness does not mean it's easy for someone to generate an alternate version of an arbitrary downloadable with the same MD5 hash. What it does mean is that if I have full control over the downloadable file, I might be able to create two versions that have the same hash value. MD5 is also often used as a mechanism to store or transmit passwords. The MD5 article does not mention this, but modern processors are fast enough to compute the MD5 value for all possible, fairly short (8 characters or less), inputs which means if I can access the MD5 hash value for your password and you have a fairly short password, I can find out what your password is. This is one reason users are often told to use long passwords. There are some theoretical weaknesses in SHA-1, but no currently known method for "fairly easily" generating two different inputs with the same SHA-1 hash value. SHA-1 also takes long enough to compute that a brute force attack on passwords is only possible for shorter passwords. -- Rick Block (talk) 14:56, 24 September 2005 (UTC)
I agree, but I would elborate that SHA-1 has also been found to be weaker than desired, although not yet in the same "fairly easily" collidable way that MD5 has. Finding a collision for SHA-1 is believed to be within the capabilities of a massive distributed Internet search (ala Distributed.net). Because of this, cryptographers (who are a conservative bunch) suggest using a different hash function in new designs, although there's not that many obvious alternatives at present. The SHA-2 variants remain unbroken for the time being. (I would also argue that the difference in speed for computing hashes for SHA-1 and MD5 is small enough that it's not worth relying on it to give any significant advantage against dictionary attacks.) — Matt Crypto 18:58, 28 September 2005 (UTC)

How to produce endorphin[edit]

(no question)

1. Laugh.
2. Enjoy.
--Sum0 17:51, 24 September 2005 (UTC)
-2 Stick your hand in a bees' nest
-1 Whip yourself with nettles
0 run a marathon
Tonywalton Pentacle-circumscribed.png | Talk 00:48, 25 September 2005 (UTC)

Alternator wire[edit]

what is the maximun voltage drop allowed on an alternator wire on a vehicle
(added header to question - Mgm|(talk) 14:22, 24 September 2005 (UTC))

I assume you mean "allowed by law". I imagine that would vary from country to country. You might want to indicate what country you are referring to? (In any case, I don't know the answer.) — Nowhither 20:01, 25 September 2005 (UTC)

Roentgenium's Color[edit]

If we could somehow produce enough Roentgenium to be visible to the naked eye (ignoring decay), what color would it be?

Probably silver-gray in colour. From its electron configuration, it will behave as a metal. With few exceptions, that's the colour that you get. TenOfAllTrades(talk) 17:33, 24 September 2005 (UTC)

Storage size[edit]

What is the storage size of a hard disk, Tape, CD-ROM,CD recordable and a DVD please can someone answer this one asap

Sounds like homework, but since it's so simple: with publicly available drives up to at least 2TB (although this is an external drive), up to 800GB, 650-700MB, 650-700MB, and 4.7GB (8.5 for a dual layer disc), respectively. For #3 and #4, larger variants DO exist, but they are fairly rare, and for #5, the capacity is twice as much for dual-sided discs. --Pidgeot (t) (c) (e) 17:28, 24 September 2005 (UTC)
It is related to the hardware ability to store & get at stuff in very small sizes (IBM has a quantum computer which records data at an atomic level, but this is still laboratory technology) and the addressing scheme. I think that 64-bit is pretty much the standard in what is economically available, but IBM reputedly has 128-bit in testing. AlMac|(talk) 18:46, 24 September 2005 (UTC)

Who discovered the treatment of Malaria?[edit]

See malaria. — mendel 22:36, 24 September 2005 (UTC)

How much does 7 liters of gasoline weigh?[edit]

Could someone who remembers more of high school chemistry tell me how much 7 liters of liquid gasoline weighs? Either metric or imperial, doesn't matter. Thanks. --Brasswatchman 20:09, 24 September 2005 (UTC)

  • Depends on the type of gasoline. Is it leaded or unleaded? High or low octane? Gasoline is usually a mixture of different components and the composition can differ per produced batch. I'm afraid giving a single answer is going to be quite difficult. - Mgm|(talk) 20:19, 24 September 2005 (UTC)
  • Our density article say gasoline's density is 0.73 g cm^-3. (I assume that's an average value, seems to match the value I got from a quick google). 7 litres is 7000 cm^3, so it would weigh 7000 * 0.73 = 5110 g or 5.11 kg. -- Bob Mellish 20:32, 24 September 2005 (UTC)
  • I wasn't looking for anything exact, just average. Great. Thanks, both of you. Brasswatchman 9:53 PM EST, 24 September 2005.
    • Alternatively, just buy a gas can, weigh it, put 7 liters of gas in it, weigh it again, and check the difference... ;) I like to go for the easy way out. --Phroziac(talk)Flag of Phyzech Republic.svg 01:15, 29 September 2005 (UTC)

Stanis?aw Ulam[edit]

How is Ulam pronounced - You-lam or Uh-lam ? Tintin 20:54, 24 September 2005 (UTC)

I've always used the latter, but I can't say if that's correct or not... Shimgray 20:55, 24 September 2005 (UTC)
According to Polish language, it would be more like Oo-lam. Physchim62 21:06, 24 September 2005 (UTC)
Yes, Oo-lam. Stan-iss-wav Oo-lam. I don't know what that is in IPA. Proto t c 13:09, 26 September 2005 (UTC)

Help me begin understanding Prolog...[edit]

Since my professor doesn't seem to intend on replying to my e-mail (this is not a homework assignment, but I have to understand the basics of this silly language in less than 10 days before the first test), I'll throw this question to fellow Wikipedians, whom I hope some know Prolog.

Given this file:

line(2, 2, 4, 5).
line(1, 2, 4, 5).
line(1, 1, 4, 4).

linelen(line(X1, Y1, X2, Y2), Z) :- DX is (X2 - X1)**2, DY is (Y2 - Y1)**2, sqrt(DX + DY, Z).

I am able to do this:

?- linelen(line(1, 5, 3, 6), Z).

And get a valid result for Z. However, if I attempt pattern-matching:

?- linelen(line(A, B, C, D), Z). or ?- linelen(L, Z). It gives me ERROR: Arguments are not sufficiently instantiated. (I've also tried all sorts of other things, all of which give me this error -- this is the most basic, though, where I began trying to write this function).

Why is it not pattern-matching? I expected it to give me the lengths of each line that I declared as previous facts, but for some reason, it is not doing this. Is there something I'm not understanding right about how pattern matching works in Prolog? I think I understand it pretty fine, but it's the syntax that seems to be killing me. What would be the "correct" way to implement this function?

Also, could anyone recommend a really good book about Prolog? Our course textbook is the one written by Mr. Ivan Bratko, who I understand had a hand in standardizing Prolog, but unfortunately it's not really that good a textbook when it comes to explaining things clearly. A good example of a programming language manual that "clicks" with me is the one for Lua written by Roberto Ieruschamily(sp?) -- are there any Prolog books like that out there? --I am not good at running 00:22, 25 September 2005 (UTC)

It's been a while since I've worked with prolog, but I think your problem is that line(A, B, C, D) is returning false. Prolog only knows what you tell it, so if I for instance wrote a program:
related(marge, lisa).
related(marge, bart).
related(marge, selma).
related(snowball II, snowball III).
Then I'm simply telling it that all the above three statements are true. So if I input related(selma, bart), it'll return true while related(snowball II, lisa) will return false. Or if I input related(selma, Z), it'll return one of marge, lisa, or bart as Z.
So your first three lines are doing exactly what I did above, only nowhere in there is there A, B, C, D, so line(A, B, C, D) will always be false. What I think you want is to cut your entire program down to:
 linelen(X1, Y1, X2, Y2, Z) :- DX is (X2 - X1)**2, DY is (Y2 - Y1)**2, sqrt(DX + DY, Z).
Like I said, it's been a while, but hopefully that helps. — Laura Scudder | Talk 00:40, 25 September 2005 (UTC)
Awesome, that seems to work. I had to do this on the query line though: ?- line(A, B, C, D), linelen(A, B, C, D, Z).. I didn't know that query lines could contain comma-delimited multiple phrases (I thought only rules could) but it seems to work, in fact be required to get it working right. Thanks! --I am not good at running 01:21, 25 September 2005 (UTC)
I think the other way to do this would be to match one of the facts in your fact base before doing the arithmetic computation as part of the linelen definition, i.e. I think linelen could be:
linelen(line(X1, Y1, X2, Y2), Z) :- line(X1,Y1,X2,Y2), DX is (X2 - X1)**2, DY is (Y2 - Y1)**2, sqrt(DX + DY, Z).
The issue is the computations cannot be done on uninstantiated variables (could be if you defined your own version of the operators using facts from the factbase). The key is you have to make sure any variables you're doing arithmetic on are instantiated to actual values at some point before you try to do the arithmetic. I learned Prolog from the Clocksin and Mellish book (a long time ago). -- Rick Block (talk) 16:41, 25 September 2005 (UTC)
Hmm that approach seems to give neater-looking results when going for an entire series of defined line(etc, etc, etc, etc). facts, but it doesn't seem to be as flexible beyond that. I rewrote my linelen as per your example, but now it only seems to allow pre-defined lines, and answers "No." for arbitrary arguments. example:
?- linelen(A, Z).
A = line(2, 2, 4, 5)
Z = 3.60555 ;
A = line(1, 2, 4, 5)
Z = 4.24264 ;
A = line(1, 0, 4, 4)
Z = 5 ;
A = line(-5, 7, 1, 10)
Z = 6.7082 ;
A = line(10, 0, 39, 60)
Z = 66.6408 ;
No
?- linelen(line(2, 7, 320, -4), Z).
No
I definitely have a better understanding of how Prolog matches patterns now than I did two days ago, especially as to how it behaves when arguments are instantiated in the definition vs. being instantiated in the query lines before the actual function. Can't wait til I get around to tinkering with cuts and fails :) --I am not good at running 19:47, 25 September 2005 (UTC)

gravity[edit]

what is gravity, how does it act on mass. D Armstrong

The answer to these questions get quite complex and philosophical; see gravity for some discussion. There are two standard theories of gravity: Newton's law of universal gravitation, which for predictive purposes is almost always "close enough", and general relativity, which can provide predictive answers in those relatively few situations where Newton's laws give slightly incorrect answers. However, general relativity is incompatible with quantum mechanics, which is our model for understanding the other fundamental forces of the universe acting at a very small scale. Therefore, our understanding of the fundamental forces of the universe is incomplete; the models we have are incomplete approximations. So ultimately, we don't really know what gravity "really" is, but we have models that can predict what it will do. But what does it mean to know what gravity "is", anyway?
Aren't you glad you asked? --Robert Merkel 03:47, 25 September 2005 (UTC)
Also see Intelligent Falling :) -- Rick Block (talk) 04:27, 25 September 2005 (UTC)

how to handle demand of medical services[edit]

Find out what the United States is doing, and do the opposite...more seriously, if I'm understanding your question correctly you might be well served by starting with our (brief) article on heatlh economics health economics, health maintenance organization, managed care, and linked articles. No country is particularly effective at handling this problem; that is, unless you take the view that the ability to pay is the proper and only criterion for determining how medical treatment should be allocated. --Robert Merkel 12:10, 25 September 2005 (UTC)

military[edit]

i have to do a presentation on how to decrease cost of military?

Firstly, I'm assuming you're American. If you're not, recalibrate this advice to specifically search for items related to your country...anyway...
Do your own homework, but have you considered doing a Google search for, say, "defense budget waste" and seen what comes up? Tried a similar search on an electronic newspaper archive, if your educational institution has access to one? Oh, and just because I'm feeling super-generous, here's one big hint: missile defence... --Robert Merkel 04:03, 25 September 2005 (UTC)
Less wars. Ojw 10:41, 25 September 2005 (UTC)
That would be fewer wars or less war. Sorry :) DirkvdM 11:20, 27 September 2005 (UTC)
I suggest you read the 9/11 commission report, and similar reports from similar commissions (about 2 a year going back in history to infinity), especially about Congress doing a competent job on oversight and cut out the pork. AlMac|(talk) 18:22, 29 September 2005 (UTC)
The percentage of GDP that goes into the military and national defense like internal security varies by nation. In the USA it was about 3% before 9/11, I suspect 4-5% now. One way to cut this down that hopefully will not happen, is to reduce it to zero, then pretty soon you no longer have a nation, because you been conquered, and now you spending 100% to the conquerors. AlMac|(talk) 21:19, 30 September 2005 (UTC)

media[edit]

How to protect people from media?

You could lock them in a room with no televisions, radios, magazines, books, internet access, etc� Not sure why you would want to do this, though. Perhaps your question could use some clarification? Garrett Albright 10:30, 25 September 2005 (UTC)

multinational organization[edit]

How to hsndle problems created by big and large multinational organization?

  • That depends entirely on the problem and the organization in question. Please be more specific. If you are unhappy with a product or service provided by a large organization, try writing a letter of complaint. - Mgm|(talk) 07:49, 25 September 2005 (UTC)

Determinants[edit]

In my far younger days, when I was but a lad running through the meadows and marvelling at the glory of the morning dew, I briefly studied some matrix-theory. Alas, those days are long gone now, and what very little I learnt has mostly been passed into the forgotten lore-section of the library that is my memory.

Now, however, I'm going to need a little help with determinants, don't ask me why :P Our article Determinants is not totally clear on this issue (ie. it's probably perfectly clear and I'm an idiot, anyway I intend to clear it up a bit if I get a satisfactory answer here)

I remember this much: If you want the determinant of a 2d-matrix you go

\begin{vmatrix} a & b \\ c & d \end{vmatrix} = ad-bc

And for three dimensions you go:

\begin{vmatrix} a & b & c \\ d & e & f \\ g & h & i \end{vmatrix} = a \begin{vmatrix} e & f \\ h & i \end{vmatrix} - b\begin{vmatrix} d & f \\ g & i \end{vmatrix} + c\begin{vmatrix} d & e \\ g & h \end{vmatrix}

So far so good, right? My question is, does this extend to higher dimensions? That is, would the determinant of a 4d-matrix be:

\begin{vmatrix} a & b & c & d \\e & f & g & h \\ i & j & k & l \\m & n & o & p \end{vmatrix} = a \begin{vmatrix} f & g & h \\ j & k & l \\ n & o & p \end{vmatrix}-b\begin{vmatrix} e & g & h \\ i & k & l \\ m & o & p \end{vmatrix}+c\begin{vmatrix} e & f & h \\ i & j & l \\ m & n & p \end{vmatrix}-d\begin{vmatrix} e & f & g \\ i & j & k \\ m & n & o \end{vmatrix}

This seems fairly trivial, but i felt it would smart to ask. Ohh, and by the way, marvel at my l33t TeX sk11lz! gkhan 05:20, 25 September 2005 (UTC)

Very good, your evaluation of the determinant is correct. Remember that you can expand along any row or column as well as the first row. Enochlau 11:57, 25 September 2005 (UTC)
But mind the changes in sign! \begin{vmatrix} + & - & + & - & ... \\- & + & - & + & ... \\ + & - & + & - & ... \\- & + & - & + & ... \\ ... & ... & ... & ... & ... \end{vmatrix} --R.Koot 19:11, 25 September 2005 (UTC)
gkhan: You should know that determinants, while being a useful theoretical tool, essentially never need to be computed. If you are simply curious about this, then that's fine. If you are interested in learning about how determinants fit into matrix theory, no problem. But if you have some practical computation for which you think you need to compute the determinant of a large matrix, then I would advise you that there are probably better ways to do your computation. — Nowhither 20:08, 25 September 2005 (UTC)
Yes, I realise that :P I'm simply curious, if I ever need to compute it, I'll use Mathematica :P gkhan 22:13, 25 September 2005 (UTC)

Places where the pressure change most obvious in one day[edit]

Is there any place where the atmosphere pressure at that place would change very obvious in a day?Could it be beaches?

The most atmopsheric pressure changes during a short period of time is when a strong tropical cyclone is approaching, preferably at a high rate of speed. For example, atmospheric pressure bottomed out in hurricane Rita at 917 mb I believe while the worldwide average is 1014 mb. -Drdisque 06:12, 25 September 2005 (UTC)

  • Do aeroplanes count? BTW, I heard a figure for 897 mbar for the minimum of Rita: the standard atmospheric pressure is 1013.25 mbar. Physchim62 10:05, 25 September 2005 (UTC)
FYI, and just to clarify, a mbar / mb is short for Millibar, where a bar is 100 kilopascals. So a millibar is 0.1 kPa or 1 hectopascal.

Information Technology Spending Patterns by Activity Sector[edit]

Hello,

As part of my Executive MBA Programme, I am examiniing Information Technology Spending Patterns by Activity Sector.

Would anybody have any sources, articles that have looked at this question in detail? I am particularly interested in the Finance, Retail and Manaufacturing Industries and in the Europe, Middle East and African region,

Thanks

Seanjoseph

--Seanjoseph 10:28, 25 September 2005 (UTC)

  1. Do a Google Search for "Research" and you will find tons of organizations that do different kinds of research, publish research reports, some of them available on-line. Google also has numerous competitor search engines, some of which are better suited to some kinds of searches.
  2. Visit each of the groups, such as Gartner Forrester many many others, and at each one use THEIR search engine, or Google limited to their domain, to find research they have already done in the areas that interest you, and which are available to you for free, Review the abstracts of those research reports to see if any of them meet your needs.
  3. If not yet successful, change the search to include those that you can purchase, for sums like $50.00, $250.00, thousands of dollars.
    1. For example, here is a link to a 4 page report which you can download for $ 250.00 from Forrester Research How Italian Consumers use Banking Channels which was just published Sep 23 of this year.
    2. At that kind of pricing, and your broad range of permutations that you need data on, you need to get as much as you can from the free sources.

AlMac|(talk) 18:28, 29 September 2005 (UTC)

Dr. Salam's Nobel Prize[edit]

what was the theory of Dr. Salam, for which he was awarded Nobel Prize in 1979 ?

See Nobel Prize in Physics. The prize was given "for their contributions to the theory of the unified weak and electromagnetic interaction between elementary particles, including, inter alia, the prediction of the weak neutral current", so it looks like he was one of the co-creators of the electroweak theory. Our article on that isn't very helpful, though... Shimgray 11:45, 25 September 2005 (UTC)
In a nutshell, he unified the theory for the symmetries which govern charged particles and those particles which suffer radioactive decay. Ancheta Wis 11:20, 1 October 2005 (UTC)

Hurricanes - how are the formed and where?[edit]

How are hurricanes formed, and where do they begin? Apart fro the western US do other arts opf the world get hurricanes? e.g. S. America, Europe, Africa, Asia? Signed Sarah B

question plz[edit]

can you tell me how water can be purified by sand gravel and pebbles or can it be only purified by sand and gravel, not pebbles. plz answer me back as soon as possible. i need to give as much information as i can to my teacher tomorrow</math>

  • Just pebbles isn't enough. They will only filter out the biggest things out. Our article on Water purification may be of use to you. - Mgm|(talk) 20:01, 25 September 2005 (UTC)

Breath Waste products[edit]

What two waste products are contained in your breath?

  • Is this, by any chance, a homework question? Notinasnaid 19:26, 25 September 2005 (UTC)
  • I'm by no means an expert on anything biological so don't take my word for this, but sometimes the tonsils (or whatever those two holes in the back of your throat are) will develop thick gobs of pus -- white blood cells, I think -- causing a really horrible odor in your breath. I usually get this when I have a cold and sore throat. I wouldn't be surprised if this were one of them, considering it's gross as hell like you'd expect from a "waste product", so look into that and see if it's true --I am not good at running
  • Don't forget good ol' Carbon Dioxide.--inks 20:47, 25 September 2005 (UTC)
  • air - oxygen = carbon dioxide + nitrogen. --R.Koot 21:01, 25 September 2005 (UTC)

education[edit]

demographic educational levels in spain?

You might be interested in our article Demographics of Spain.  --  W  P Talk 06:01, 28 September 2005 (UTC)
If you go to the CIA World Fact Book, it has by nation, things like literacy rates for men, women, other subdivisions relevant to that nation. AlMac|(talk) 21:21, 30 September 2005 (UTC)

Iron Supplements & Dental Caries[edit]

Does Supplementary Iron drops in childrens cause dental caries? ---~~|

As a molecular-biologist-in-training, I would be surprised if they did. Have you tried searching with those terms on Pubmed? [5] --inks 02:18, 26 September 2005 (UTC)

The Color Spectrum[edit]

When was the Optical Color Spectrum founded? Who dicovered the wavelengths and in what year did the factual evidence occur?

Isaac Newton discovered the spectrum (I belive he discovered it in his anno mirabilis, 1666), although he thought light was made of particles (which it turns out it kinda is, and well, kinda isn't). The first to surmise that light was made from wavelengths I'm pretty sure was Thomas Young using his double-slit experiment in 1801. By the way, that experiment, it's ridiculusly cool. What do you mean by factual evidence? Both Newton and Young had factual evidence (Newton saw the spectrum, Young saw the wave-interference). For more info, see Optical spectrum gkhan 03:27, 26 September 2005 (UTC)
Well, Newton recognised the spectrum for what it was. After all, the spectrum is shown in things like the rainbow, so the first person to notice that is lost in the mists of time. --Fangz 12:49, 26 September 2005 (UTC)
Noticing the colours of the rainbow is not the same as realising that they're constituent parts of white light. And the first person (as far as is known, I must admit) was not Newton but Roger Bacon, in the 13th century. That's 4 centuries before Newton! This guy was way ahead of his time in many fields and deserves to be just as well known as Newton, Aristotle, Galilei and the like. He could be seen as the first modern scientist, although he did dabble in stuff like alchemy as well, but then that was the chemistry of the day, so to say. DirkvdM 11:28, 27 September 2005 (UTC)

How many fault lines are there[edit]

A whole bunch. Each boundary lines is a geologic fault, but according to the article, there are a whole mess of faults that are nowhere near any tectonic plate-boundaries. gkhan 03:34, 26 September 2005 (UTC)

Gravity and its effect on the human body[edit]

Hi Science Wizards; My question is ,does Gravity have any measurable effects on the human body and if so how are these effects measured ? Does gravity effect the body different at night then during the day ? Are its effects different if we are standing or lying down?

                                    Thank you , this site is great ,Sincerely Dennis NIgrelli
Gravity has many effects on the human body. Off the top of my head, I can think of how the fluid pressure in the feet is higher than in the head when you're standing, thus the need to elevate the feet for many medical problems. Another issue is that gravity causes the pressure and stresses in you're skeletal system. I know of at least one bio-engineering researcher studying how to grow artificial menisci who has discovered that to grow them properly, you need to simulate the force on them that would be present in a growing child. You might be interested in the sorts of medical experiments that NASA has performed on its astronauts on how low-gravity environments affect the body, sometimes called space medicine. — Laura Scudder | Talk 04:02, 26 September 2005 (UTC)
(added after Edit conflict, so I might be parroting a little) Does gravity have any effect on the human bodies? Throw yourself off a skyscraper and check ;). That is, earth has a very big effect on the human bodies, it keeps us on the ground. Prolonged abscence of gravity is very harmful for the human body, your bones start to degrade almost instantly. Thats why astronauts has to be carried off their shuttles. Night and day or standing or lying down has no effect, the only thing that affets gravity is mass of the two objects (in this case, your bodymass and the mass of the earth) and distance to center of gravity (=center of earth). There is however a noticable difference in weight (note:weight, not mass) is if you are closer to the equator. At the equator, you are farther from the center of the earth (since earth isn't a perfect sphere) and you are influenced by the centrifugal force of the rotating earth. I've heard that it's a few Newtons difference from Sweden where I live (which would translate to a few hundred grams). gkhan 04:08, 26 September 2005 (UTC)
In case you are not enrolled in a space program, I've heard (although couldn't find it in Wikipedia, so it could be urban myth) that your spinal disks compress during the day due to gravity, so that at the end of the day you are a couple of centimetres shorter than you are after a nights rest (when you are horizontal your disks can expand). --Commander Keane 06:41, 26 September 2005 (UTC)
Another aspect of gravity affecting the human body is its effect on those subject to high-G, for example fighter pilots. A high-G turn can cause the pilot to lose vision and eventually consciousness. They wear special suits, G-suits, to help protect against it. Which brings me to the other point. There is no difference between the effect of G at night or day, but it does make a difference if you are lying down or not. You are less prone to blackout if you are lying down. DJ Clayworth 17:08, 26 September 2005 (UTC)

Heat suits and ambient vs. radiant heat[edit]

This crazy moon-man suit protects the wearer from 1500�F ambient heat and 2000�F radiant heat. This less-crazy moon-man suit still maintains 2000�F radiant heat, but only 200�F ambient. What do they mean by "ambient" and "radiant" heat? What sort of things would one need a 2000�F/200�F suit for? I read over Heat and Thermal radiation and understand what thermal radiation is, but I can't figure it out in terms of those suits. (Not that I need to know for any practical reason, but it's bugging me that it's not obvious to me.) — mendel 04:46, 26 September 2005 (UTC)

As I understand it, ambient heat is the temperature of air in a location, and radiant heat is the temperature to which a solid body in that location would be raised to by the thermal radiation. You can reflect thermal radiation, but you can't "reflect" the ambient temperature, so it's not surprising that it's much easier to protect against radiant than ambient heat. --Robert Merkel 05:47, 26 September 2005 (UTC)
Oh, and this page on that website says pretty much the same thing I just did. --Robert Merkel 05:50, 26 September 2005 (UTC)
I must have read right past that section, thanks. I'm now thinking about "1500� in the shade!" — mendel 19:16, 26 September 2005 (UTC)

Computer Safety - list of free mp3s[edit]

Through a site I trust (a wiki no less!) I discovered something called Webjay which appears, according to its newbie FAQ, to offer playlists of free mp3s compiled by users who simply link directly to external legal mp3 files, (eg this playlist of tracks John Peel is supposed to have played).

I've never previously been scared of mp3 files. As far as my knowledge goes, mp3 files are not a security risk to my machine. But, I suppose this just seems a little too good to be true ;o) My question is, simply, is it safe?

Whilst I'm here, what do Wikipedian Windows users use for anti-virus software? I have always used Norton, but due to some of the ways I've been using my machine lately I've come to share the seemingly prevalent view that Norton slows down your system. --bodnotbod 06:24, 26 September 2005 (UTC)

The corporate versions of Symantec anti-virus are less resource-hungry than the consumer versions. I don't know why. I run Symantec Client Security on my Windows machines. I don't know if a consumer can buy it - I got it for free from work before I left. I've heard AVG is quite reasonable and it's free for non-commercial use.-gadfium 06:47, 26 September 2005 (UTC)
I would be very surprised if a .mp3 or .m3u file posed a security risk in itself (of course, you can rename any file to a .mp3/m3u). ATM, I don't run any anti-virus software, and have not for a few years. Then again, I don't use MS Outlook either :)--inks 10:49, 26 September 2005 (UTC)
I recall hearing about some programs that had a security error with ID3 tags, allowing a buffer overflow. I don't believe it's a threat if you use an updated player, though, like Winamp 5.10.
As for anti-virus, AVG is a very good program. Not to mention free. ^_~ --Pidgeot (t) (c) (e) 11:08, 26 September 2005 (UTC)
  • At the moment I run a free version of AVG anti virus. - Mgm|(talk) 08:06, 26 September 2005 (UTC)
    • At home I run AVG free on my laptop and AVG paid-for on my main PC. The main benefit of the paid-for version is the customisability (if there is such a word) of the tests and test/update scheduling. Unless you want to fiddle with settings and the like then the free version is more than adequate. Thryduulf 14:24, 26 September 2005 (UTC)
      • Well, that's quite a vote of confidence in AVG. I too am pretty good, I believe, in terms of surfing safely and did manage not to get any nasties for years without running any guard at all. The only thing that's stopping me dumping Norton immediately is that - if I recall correctly - I only PAID to renew my subscription about 4 months ago. But I've already lost the money and there's no point being a damn fool about using a slowed computer unnecessarily, I suppose. --bodnotbod 01:32, 27 September 2005 (UTC)

Hurricanes[edit]

Dear Sirs,

I am currious to know if the water picked up over the ocean by a hurricane and is later dropped over land, is salt water or fresh water when it hits the ground? How does the hurricane suck the water up and if the rain droped is fresh, where does the salt go? Does the salt stay in the Ocean because it is too heavy or does it evaporate during the picking up of the moisture process? --[User:24.58.206.102|24.58.206.102]] 14:02, 26 September 2005 (UTC)

First, please do not indent text by pleaving blanks at the start of paragraphs on wikipedia. it formats your text as mon-spaced, unwrpped, which is good for a few special purposes, but not for ordinary text.
Secxond, the water evaporates from the ocean surface and joins the hurricane as water vapor. This leaves the salt (and anything else dissolved) behind. Thus any rain is fresh water. DES (talk) 14:13, 26 September 2005 (UTC)
I believe it's just tornadoes that suck up thing. Right? DirkvdM 11:51, 27 September 2005 (UTC)
Rubbish, not everyone believes in water vapor, molar heat capacaties are just the work of evolutionsits and other unsavory types (; trying to force their damn theories on everyone, I like my globe flat, and pancake like, not all spherical like *some* people want it
In USA all you have to worry about with what "sucks up" is tornadoes and man made out of control. Elsewhere in world are water spouts that behave something like tornadoes except are over water.
Also a lot of the water that ends up on the ground in the aftermath of the Hurricane, did not come from the sky, but from the surface, either via storm surge, or flood control breakage. [User:AlMac|AlMac]]|(talk) 18:40, 29 September 2005 (UTC)

Computers Solving Mathamatical Problems[edit]

Do mathamagicians accept that computers can solve very complex problems?

for example. The four colour map theory has been solved by computers for a massive ammounts of polygons. However, many people still say that it has never been solved as a computer did it.

I dont get it! Please help

While it has been proven, many mathematicians find an exhaustive search so unelagant they don't want to call the verification of all posibilities a proof. One very good reason is that such a search does not give provide a deeper insight in why this it is true, which is often considered more important than the fact that it is true (see four color theorem). Also, most problems cannot be solved in this way, because an infinite number of cases have to be tested, or an amount simply too large. For example, the weak goldbach conjecture. Also if we would be able to lower this bound so that we could do a computer search, this would be rather pointless as the conjecture is of no practical use and a computer search would provide no intellectual challence. --R.Koot 14:22, 26 September 2005 (UTC)
The various computer-assisted proofs of the four color theorem are examples of a method of mathematical proof called proof by exhaustion. A computer-assisted proof by exhaustion involves the following steps:
  1. Show that a problem can be reduced to solving a finite (although possibly very large) number of special cases
  2. Devise a method of solving any one of these special cases through a finite (though again possibly very large) number of calculations
  3. Write a computer program to apply this method to each of the special cases, with cross-checks to detect mistakes in design or programming or run-time errors
  4. Run the program
  5. Publish the program, the results and an explanation of the method in an accessible form.
Only step 4 is actually carried out by the computer. The reservations that some mathematicians might have about such proofs are more to do with the difficulty of completely validating any long and complex proof, and the lack of insight inherent in the proof by exhaustion method, rather than the fact that a computer has been used. Gandalf61 14:44, 26 September 2005 (UTC)
Original poster: You have perhaps been reading some out-of-date information.

It is true that we are not very happy with large computer-based proofs, because they are not very elegant and they give us little insight into what is really going on. Further, they force us to base notions of absolute truth on whether some particular electronic circuits were functioning properly.

However, the most important problem with the mid-1970s Appel-Haken-Koch proof of the Four Color Theorem is that no one has ever checked it independently. A group of researchers (Robertson, Sanders, Semour, Thomas) decided to do the checking in the early 1990s. They eventually found it easier to produce their own computer-aided proof, which followed similar lines, although it was a bit simpler. This proof has been checked independently. Further, you can download their program and run it yourself.

So now we can be quite confident that we do have a proof of the Four Color Theorem. And mainstream mathematical culture generally accepts computer-aided proofs these days. Although we still prefer traditional proofs, for the reasons of elegance and insight that I mentioned above.

Nowhither 18:04, 26 September 2005 (UTC)

Just as a sidelight, computers can still be useful for numeric methods of calculation. For instance, there exists a class of mathematical functions which an integral exists, but cannot be found. A computer can approximate the value of such an integral using numeric methods when traditional mathematical methods cannot.

what is the freezing temperature of alcohol?[edit]

Does alcohol freeze as how water would freeze? If so what temperature does it freeze at?

There are many different kinds of alcohol, and they all have lower freezing (and boiling) points compared to water, which freezes at 0�C, or 32 F. The one you're probably thinking of is ethanol, which is the alcohol in alcoholic drinks. In normal atmospheric conditions, ethanol freezes, in much the same manner as water, at -114.3 �C, or -173.74 F. Proto t c 15:08, 26 September 2005 (UTC)

A minor nitpick...the low molecular weight alcohols freeze and boil at much lower temperatures than water; the longer chain ones freeze and boil and higher temperatures. Methanol (one carbon), ethanol (two carbons), isopropanol (rubbing alcohol, three carbons) are short chain alcohols. By the time you get out to dodecanol (also called lauryl alcohol) you're up to twelve carbons, and the stuff freezes and boils at 24�C and 260�C, respectively. TenOfAllTrades(talk) 16:16, 26 September 2005 (UTC)
Alcohol is also hydroscopic (i think that's the term), which means it attracts water. Normal rubbing alcohol has 30% water in it. When they make "moonshine" (ethanol), the still is used to boil the alcohol off the water, which boils at a much lower temperature. Anyway, having an amount of water in will raise the freezing point. --Phroziac(talk)Flag of Phyzech Republic.svg 01:10, 29 September 2005 (UTC)

Andrew C. von Eschenbach[edit]

What is his biography?

See Andrew von Eschenbach. TenOfAllTrades(talk) 16:06, 26 September 2005 (UTC)

Computer storage media[edit]

What are 5 different storage medias with their descriptions, capacity levels, advantages, and disadvantages? Where did you get this information? --63.199.33.66 16:40, 26 September 2005 (UTC)

Please refer to the instructions at the top of the page, and note that Wikipedia is not here to do your homework for you. I would recommend starting at our article on data storage devices, and working from there to find the information that you need. TenOfAllTrades(talk) 16:51, 26 September 2005 (UTC)
DYOH, but a similar question was answered above at #Storage size. Garrett Albright 19:21, 26 September 2005 (UTC)

I dont think its homework... Would you classify a extra credit project "Homework"?

Of course. I already did my time in the public school system and four years of university. I've done my share of schoolwork, and I'm really not interested in doing any more anytime soon, and especially not someone else's. Garrett Albright 18:51, 29 September 2005 (UTC)

diseases?[edit]

what is the difference between a communicable disease and a pathogenic disease?

  • Pathogenic diseases are caused by pathogens (outside sources) while communicable diseases are diseases that can be transmitted between individuals. Most diseases that are communicable are caused by pathogens, but not all pathogenic diseases can be transmitted.- Mgm|(talk) 22:06, 26 September 2005 (UTC)

Next round of the endless Moth Identification Game[edit]

My friend is keen to have this moth (right) identified, which he describes as "huge". Any takers?

I'm suffering from an identity chrysalis

--bodnotbod 18:57, 26 September 2005 (UTC)

Isn't this an Owl butterfly? Rmhermen 13:46, 27 September 2005 (UTC)
Well, it's a world I know nothing about, much less the subtleties - but on a quick look at the link it would certainly seem to match. I'll pass that on, thank you. --bodnotbod 17:50, 27 September 2005 (UTC)

orcas[edit]

Hi. Are the Orcas in the fiords of Norway there yet? Thanks.

permutation cipher[edit]

What is the purpose in standards of wiring?[edit]

The subject pretty much sums up the question.

Why do you ask? You see, the way you ask it makes it sound a bit like a homework question. Notinasnaid 19:53, 26 September 2005 (UTC)
Standards (such as AWG-American wire gauge) save money, reduce effort, and create repeatable results. Ancheta Wis 11:28, 1 October 2005 (UTC)
You also might be interested in knowing about standards for the manufacturing of wiring. AlMac|(talk) 04:01, 3 October 2005 (UTC)

what is dual axle white balance[edit]

I'm assuming you meand "dual axis". Color temperature provides a hint: "Color temperature" is sometimes used loosely to mean "white balance" or "white point". Notice that color temperature has only one degree of freedom, whereas white balance has two (R-Y and B-Y).. So I'd guess (never having seen the expression before, and only coming up with a single Google hit) that simpler cameras use a one-dimensional adjustment (color temperature), calling it "white balance"; while fancier ones (like the Canon EOS series, the only context in which Google found something) have a two-dimensional adjustment. --jpgordon∇∆∇∆ 22:22, 26 September 2005 (UTC)

Space[edit]

How did the space program come to in the US after world war 2? -jody

  • Perhaps our NASA article can help you find some answers. - Mgm|(talk) 22:11, 26 September 2005 (UTC)
  • The program to get German rocket scientists (and, indeed, rockets) out of Germany was known as Operation Paperclip. Shimgray | talk | 23:28, 26 September 2005 (UTC)
Ironically, you could say that the USSR got the space program into the USA. Werner von Braun was brought to the USA to work on nuclear missiles (since he had designed the V2). He really wanted to work on space rockets, but only after the USSR went to space did politicians start listening to him. DirkvdM 12:00, 27 September 2005 (UTC)
Traditionally, until sputnik, the US space program was hopelessly underfunded, then sputnik was a shock to the US psyche, much like Hurricane Katrina is a recent shock leading to a renewed effort to do a competent job managing infrastructure and disaster avoidance. After the US Space Program got to the Moon, US public support for funding evaporated, and NASA got kind of Lost in Space. AlMac|(talk) 18:50, 29 September 2005 (UTC)
See space race. Ancheta Wis 11:32, 1 October 2005 (UTC)

Chemistry[edit]

Dear Chemists:

I need to know exactly how much HCL acid and distilled water to combine to arrive at a liter of 1.5M solution of dilute HCL acid. Note: I am using 31.45% Muriatic acid for this project. If possible, please tell me how you arrive at the answer.

Thank you in advance! Docfrickey

I should point out that you'll never be more than premedfrickey, if you really need wiki to do your general chem homework--205.188.117.71 03:59, 29 September 2005 (UTC)
Let me try. From Hydrochloric Acid (which is Muriatic acid by a different name), we know that HCL is 36.46 g/mol. For 1L containing 1.5M, you need 36.45*1.5=54.675g. A 31.45% solution of HCL has 31.45g (or 0.86 mol) of HCL/100ml, so you need 1.5/0.86*100ml=174ml of 31.45% HCL solution. Make up to 1L with 826ml of distilled water. Can someone else check my numbers? I was never very good at this :) --inks 23:18, 26 September 2005 (UTC)
These values of 174ml of 31.45% HCl and 826ml distilled water are correct. You get a solution of exactly 1.5M.Borbrav 05:48, 27 September 2005 (UTC)
To be precise, you should use 174ml of 31.45% HCl, and then add enough water to make 1000ml of solution. The water you need to add might not be 826ml, because there's no guarantee that volume is conserved when mixing liquids. Chuck 22:44, 27 September 2005 (UTC)
  • Docfrickey,

I have removed your e-mail address. The response isn't by e-mail and keeping it in such a high-traffic site means you will receive plenty of Spam and Phishing attempts. Capitalistroadster 05:59, 27 September 2005 (UTC)

Muriatic Acid contains Zinc Chloride, I hope this does not mess up the experiment.

I can find no indication that Muriatic Acid is HCL + Zinc Chloride. Everything I've found so far says it's an old name for Hydrochloric Acid. I would venture that if there is ZnCl in your HCL solution, unless told otherwise you should assume there are trace quantities only, and ignore it with regards to your calculations. Also, tell your chemistry teacher (or lecturer) to stop using outdated terminology! :)--inks 21:44, 27 September 2005 (UTC)
You would never do it this way for at least three reasons:
  1. 31.45% Hydrochloric acid is corrosive and so it is difficult to measure an accurate volume.
  2. Solutions of hydrochloric acid at that concentration tend to lose hydrogen chloride gas to the atmosphere, so you cannot be sure of the exact concentration.
  3. Volume measurements are intrinsically inaccurate (0.1% accuracy at best), so the calculated concentration would not be sufficiently precise for further high precision work
Message to your teacher ('cos this sound like a homework question): think up more realistic situations for your students' exercises! Physchim62 14:59, 28 September 2005 (UTC)
No. Point 1: Corrosivity hardly affects measurement especially in glass instruments; Point 2: Yes it does off-gas, but it is hardly significant. In fact, these concentrations are standard laboratory stock; Point 3: Volume measurements are accurate and precise enough for a wide variety of applications. Rmhermen 03:36, 29 September 2005 (UTC)
Point 1: Of course corrosive liquids can be measured in glass apparatus if you know what you're doing (I can remember pipetting bromine as a postdoc), but it is not recommended if there are alternative solutions (as here); Point 2: Standard lab stock is 35–37%, you would be a fool to trust a concentration given to four significant figures; Point 3: True, but you would never prepare either a standard solution (ie precise concentration) or a reagent solution (imprecise concentration) by the method that the questioner requests.
For reagent 2M hydrochloric acid, add 200 mL conc. hydrochloric acid to 800 mL water. For standard 0.1M hydrochloric acid, start with the reagent diluted acid as prepared above, titrate it against sodium carbonate using methyl orange as the indicator, dilute it appropriately and retitrate the diluted solution to obtain the precise concentration. Physchim62 07:40, 29 September 2005 (UTC)

how much water does asparagus use[edit]

How much water does Asparagus use to grow? To cook? To wash his car with? Our article on Asparagus has links at the bottom to websites describing how to grow and cook it, and hopefully one of them contains what you want to know :) --inks 00:35, 27 September 2005 (UTC)

mission critical[edit]

Wht does mission critical mean?

It denotes something (or even someone) that is of crucial importance to a particular objective, or mission. Very generally, without a mission critical item, the mission cannot proceed or be completed.--inks 00:44, 27 September 2005 (UTC)
  1. Think of the infrastructure that is essential to some mission or objective. If the Infrastructure fails, then the objective fails. Examples:
    1. In the aftermath of Hurricane Katrina many hospitals lost electricity, telephones, ability to be resupplied by ambulances, did not get fast enough helicopter service, so they were not able to keep all the patients alive. In this sense we can say that some of the infrastructure of the hospital was mission critical to the patients who were in dire straits.
    2. Think of the role of computerized recordkeeping to the notion of business continuity. If the computer gets trashed, if the backups are ruined, then perhaps the business cannot continue operating. Thus a system, for keeping backups out of harms way, is said to be critical to the mission of keeping the business continuing.

AlMac|(talk) 18:55, 29 September 2005 (UTC)

What is this insect?[edit]

red & black bugs eating daisies in the desert

Long time answerer, first time asker: What is this insect? The photo is from Anza Borrego Desert State Park near San Diego, CA.

Thanks, --Joel 02:34, 27 September 2005 (UTC)

Do insects eat while copulating? :) DirkvdM 12:04, 27 September 2005 (UTC)
Sure, they use their short lifetime very efficiently, and so would I if I thought I could get away with it. Shantavira 17:06, 28 September 2005 (UTC)
I can add more photos if that would help, but I'm still curious as to what these things are.--Joel 16:07, 29 September 2005 (UTC)

Lightning?[edit]

What is lightning?

Have you seen our article about Lightning? It has some wonderful photos, and explains the phenomenon well.--inks 05:47, 27 September 2005 (UTC)

records management.what is a record?it's life cycle& why do organisation maintain records?[edit]

Our Records management article should provide some assistance. Capitalistroadster 09:22, 27 September 2005 (UTC)

Do you personally pay any kind of taxes? Do you keep any records so that you can correctly calculate them and prove what you owe in case you get audited? Companies are even more interested in making sure they do not get over-taxed. AlMac|(talk) 01:11, 30 September 2005 (UTC)

Quantum Decoherence[edit]

What does quantum decoherence means? I know its the collapse of the wave function, but what exactly is it. Can anyone exlain it in a simple, conventional way without using much maths?

FireFox Bookmarks Directory[edit]

Where is the directory path in which favorite sites are bookmarked in Firefox Mozilla browser?

For 2000/XP, look in C:\Documents and Settings\<Windows username>\Application Data\Mozilla\Firefox\Profiles\default.7pr, assuming you aren't running with multiple profiles. --Pidgeot (t) (c) (e) 11:34, 27 September 2005 (UTC)
A simplified version of the above is
%AppData%\Mozilla\Firefox\Profiles

You can't paste the "default.7pr" because the extension varies by installation. However, you go into the default folder and grab bookmarks.html

algorithms[edit]

How to clean up acid spill?[edit]

Depends upon how much acid, also depends upon what kind of acid. Small spills can be cleaned up via adding a base, or alkaline substance found around the home. Typical substances are Sodium bicarbonate, ammonia and lye. Sodium bicarbonate will froth profusely in contact with acid, ammonia can be toxic in large concentrations so make sure you have plenty of ventelation, lye will burn the skin if left in contact for a prolonged period so make sure you wash it off or even wash with a solution of vinegar. Some acids, like prussic acid are deadly poison so get out of the area fast, others like acetic acid found in vinegar are not very dangerous, so washing with water would be good enough. Large spills often are taken care of by nature herself as carbonates in the soil react and neutralize the acid.

Still a lot depends upon the acid, how much and where the spill was.

If your worksite is in OSHA's jurisdiction and keeps big jars of acid around, it should have a "spill kit" with thick rubber gloves and a box of deluxe cat litter, which both absorbs and neutralizes. The absorbent they use for chemical spills often has a pH indicator in it, so that it turns from pink to blue when you've used "enough" (subject to the manufacturer's judgment, this might be "more than a reasonable person would use in any circumstance"...). Plain cat litter will work just as well, if you use common sense and don't get out the broom until the acid is completely soaked up.
I also aggree with the earlier editor that it matters what type of acid (LSD, for instance, is another matter entirely), but also what concentration: if you have spilled a large ammount of glacial acetic acid, you might have trouble breathing in that room until the cleanup is done, so it might be wise to call someone with a respirator and the training to use it properly.--Joel 22:21, 27 September 2005 (UTC)

production manifolds[edit]

platform[edit]

er...platform lists quite a few subjects, from shoes to weapons, cars to politics, oil, tectonics, computers, and railways. Read through it until you find what you're looking for, or come back with a more thorough question. Or try wiktionary:Platform if your command of the English language is the problem.--Joel 22:35, 27 September 2005 (UTC)

What is NokiaNet?[edit]

Hi,

I have been in the mobile wolrd for in excess of 15 years and I have come across a type of Service similar to Blackberry but referred to as NokiaNet.

I will appreciate if anyone can help me understand what this Service is?

Many Thanks

Rohit

What are all the hidden processes in windows XP?[edit]

If I press ctrl+alt+delete, I currently have 31 processes running, most of them unknown by me.

Is there any place (preferably wikipedia) I can find a list of what these are?

You can usually just type the process name into a search engine (like Google) and you'll find information on it as the first result.
Or, you can list them here, and we can try to tell you what they are. --Pidgeot (t) (c) (e) 15:08, 27 September 2005 (UTC)

five sense's[edit]

  • what are the five sense's ?
  • also, note that there seem to be more than 5 --WhiteDragon 17:38, 28 September 2005 (UTC)

Jumpdrive's, Compadibility, size, and price.[edit]

Can anyone please help, and find information about a Lexar Jumpdrive secure, 256MB, and any other type of Jumpdrive, Nerd Key, Flash Drive. I am looking for the size, a advantage, a disadvantage, and a discritption. Any ideas? -Lord Ned


KK Thanks Lord Ned

That's a pretty bad cold you have there. DJ Clayworth 21:44, 28 September 2005 (UTC)

carbon dioxide in the body[edit]

I understand that carbon dioxide buildup in the body is what triggers "air hunger" in a heavy carbon dioxide environment, but that a helium environment wont cause such a reaction, leaving a mamal unable to sense the loss of air and therefore vulnerable to suffocation. Is this true?

  • Yes, I believe it is, at least in humans (not sure about all mammals). The body doesn't detect lack of oxygen, it detects too much CO2. So if you displace the oxygen in a room with an odourless gas like He or N2, there's no feeling of suffocation to warn you that you can't breath. -- Bob Mellish 17:50, 27 September 2005 (UTC)
  • Though if you're a member of the popular mammal species homo sapien, and are in company, you might detect an unhealthy amount of helium in the atmosphere when you all start talking like Disney's Chip 'n' Dale --bodnotbod 18:49, 27 September 2005 (UTC)

No, no, no, DrBob. The CO2 in the blood that drives breathing comes from body metabolism, not the surrounding air. Prevention of breathing it out is what makes you feel out of breath. Breathing is also driven by hypoxia or rising acid level, but these drives are weaker than the CO2-linked response. alteripse 21:09, 27 September 2005 (UTC)

  • So what mechanism prevents you breathing out CO2 in a non-oxygen atmosphere? Or am I misunderstanding you? -- Bob Mellish 22:05, 27 September 2005 (UTC)

Nothing prevents you from breathing out CO2 in a low oxygen atmosphere. That's why people can sometimes die of hypoxia as long as they can exhale CO2. alteripse 00:21, 28 September 2005 (UTC)

Let me see if I can make it clearer. There are at least 5 types of control for the physical act of respiration: (1) voluntary breathing, e.g., blowing at something or talking; (2) involuntary neural control based on a rhythm of breathing controlled by neuronal pacemaker cells in the medulla; this is what keeps someone breathing in a vegetative state and why a brain injury that affects the medulla can kill someone; (3) chemical control by arterial blood carbon dioxide levels; rising levels stimulate breathing; (4) chemical control by arterial blood oxygen levels; falling levels stimulate breathing; and (5) chemical control by arterial blood acid (pH) levels; falling pH stimulates breathing. The CO2 and acid in the blood are generated by aerobic metabolism of body cells no matter what you are breathing.

Exhaling CO2 does not depend on the content of the ambient atmosphere but whether your lungs are working and your airway is unobstructed. Physical obstruction of breathing by a hand over your nose and mouth will prevent you from exhaling CO2 and inhaling O2, as will prolonged closure of the epiglottis as occurs in drowning; as will failure of respiratory muscles (e.g. Guillain-Barre syndrome) or severe lung disease (e.g., adult respiratory distress syndrome). In all these cases you die with a high CO2 level in your blood, low pH, and low O2 level.

However if nothing impairs your breathing but the oxygen is removed from the air, you will continue to exhale CO2 but your O2 level will fall. Most people and animals sense this before they become unconscious from hypoxia but not always, and increased breathing of a low-oxygen atmosphere does not improve the oxygen levels and the person or animal will become unconscious fairly quickly. This is why people are overcome by collections of heavy gas in sewers or chemical tanks, and a rescuer can die of hypoxia before extricating the initial victim. Just before their respiration becomes impaired, they will have a low blood O2 level and a low CO2 level; as the hypoxia affects the medulla and breathing ceases the CO2 and acid level will abruptly and rapidly rise.

The earth's atmosphere is about 21% O2 but less than 1% CO2. The rest is mainly nitrogen, but you can substitute all kinds of other gases like helium as long as you supply at enough oxygen and the other gas is not intrinsically harmful (like carbon monoxide). CO2 is not a damaging gas, but breathing an atmosphere of 21% O2 and 79% CO2 would result in rising levels of CO2 and acid in the blood because gas exchange in the lungs depends on a gradient between blood and ambient air.

Of the chemical controls, the CO2 drive is stronger than the O2 or pH drive. All of the chemical controls can gradually habituate to altered levels (e.g., as occurs in emphysema) and sudden changes can cause problems. A sudden drop of blood oxygen that causes hypoxia will impair and damage the brain in minutes. A sudden drop of CO2 (e.g., from hyperventilation) will upset the acid/base and cation balance of the blood and can cause a variety of symptoms, including panic. A sudden rise of CO2 in some circumstances can actually impair brain function and the neural drive to breathe: this is referred to as "CO2 narcosis".

Finally, it seems that all air-breathing vertebrates have similar respiratyor control mechanisms. Antoine Lavoisier discovered some of the properties oxygen by observing the effect on mice of altering their ambient air. This is probably way more than anyone wanted to know but does it answer your question? alteripse 08:59, 28 September 2005 (UTC)

So to summarize briefly, in a helium evironment, you would still have hypoxia and pH inbalances. Therefore, you would know to keep breathing, but the drive wouldn't be as strong because there was no CO2 build-up. Because you wouldn't be able to get any oxygen, you would die of hypoxia, possibly recognizing your discomfort but possibly not noticing before you fell unconscious then died. Is that basically right? Superm401 | Talk 21:39, 28 September 2005 (UTC)

You got it! alteripse 18:50, 1 October 2005 (UTC)

Fish[edit]

is goldfish coldblooded? - anon

  • Fish are coldblooded by definition. - Mgm|(talk) 20:32, 27 September 2005 (UTC)

Actually, I believe by their physiological processes rather than by human definition. alteripse 21:11, 27 September 2005 (UTC)

Tuna tend to keep an elevated body temperature, and swordfish have special muscles which keep their retina and optic nerves warm [6], but yes, most fish (especially small ones!) are cold-blooded.--Joel 23:13, 27 September 2005 (UTC)

Gasoline Shelf Life[edit]

Hi! I was wondering how long automobile gasoline lasts when stored in ideal conditions? Does its quality diminish? Does it last practically indefinitely? What happens? What does it turn into? The first question is the most important to me so feel free just to answer that one. Thank you very, very much! ~~Charles Reid (Houston, TX)

According to Chevron, their gasoline can be stored for about a year under ideal conditions[7]. We do have an article on Gasoline, although it doesn't seem to say much about long term storage.--inks 21:27, 27 September 2005 (UTC)
I recall a question on this a while back. The answer I got from my small-engines teacher when I was in high school is that it gets "gummy", which I assume means polymerization of the unsaturated hydrocarbons that are the most cost-effective way to boost octane number.--Joel 23:27, 27 September 2005 (UTC)
Also worth noting that in some countries gasoline is classed as hazardous, and it is illegal to store it in any quantity. Also note that in time gasoline will cause some types of container, especially plastics, to deteriorate. Shantavira 17:16, 28 September 2005 (UTC)
I also took a small engines course. I don't know the chemical terms for it, but it will partially solidify into a useless goo. This happens mostly in small things like the insides of a carburetor, but not in any significant quantity in a larger container. A while back, I took apart a carburetor that had been sitting with gas in it for a few years, and it had large chunks in the "bowl". --Phroziac(talk)Flag of Phyzech Republic.svg 00:30, 29 September 2005 (UTC)
Is that why it is stored in those drums?
Through being a moron and leaving gas in things when they haven't been used in years, I can firmly say that pretty much anything made to hold gas will not deteriorate from gas. I know that gasoline will melt pop bottles fast though... --Phroziac(talk)Flag of Phyzech Republic.svg 00:30, 29 September 2005 (UTC)
Gasoline will only stay fresh for about a month in a vented container, such as a fuel tank. It will change, and can cause a lot of engine troubles, such as the engine not running properly. It can also coat the inside of the engine with excessive amounts of junk. Interestingly, when it goes bad, the smell also changes, it smells more like actual varnish or paint then gasoline. You can, however, use a "fuel stabilizer", such as Sta-bil, which can be found at hardware stores, lawnmower shops, and automotive shops. It will last indefinitely with fuel stabilizer, as long as the container isn't open to the air. This includes vented gas tanks, though it will obviously stay fresher if it's sealed. Never leave unstabilized fuel in the fuel system for an engine for more then a month or so, it will gum up inside the carburetor or fuel injectors fairly quickly, and often requires soaking the carburetor in a cleaner and rebuilding it. I don't know anything about fuel injection systems, other then they are much better then carburetors. Also, this next part is original research, but apparently kerosene can be stored indefinitely in a sealed or vented container, and diesel goes bad faster then gasoline. --Phroziac(talk)Flag of Phyzech Republic.svg 00:30, 29 September 2005 (UTC)

Dr. Meyer[edit]

Kastle invented the presumptive blood test in the 1900's using phenolphthalein, then was further developed by Dr. Meyer later on. What was his first name?

Blood test for what? alteripse 21:24, 27 September 2005 (UTC)

I think he's referring to the inventors of the Kastle-Meyer Color Test, which uses a solution of phenolphthalein and hydrogen peroxide to detect the presence of blood via a color change. There is a passing mention of it in phenolphthalein. I've had no luck with Googling for Dr. Meyers full name though.--inks 21:35, 27 September 2005 (UTC)

Satellite imagery[edit]

Are there any satellites up there that will photograph to the clarity and detail of showing a man or woman walking on earth ?

If I told you, I'd have to kill you :) Our article on spy satellites has several listed that have a resolution of less than 1m...so a person lying down might be distingusihed. However, a person standing up would present a much smaller cross-section to the satellite, the size of which would probably fall below the resolution availible.--inks 22:42, 27 September 2005 (UTC)
Diffraction means that a much smaller angular resolution than the 1m reported would require either a) extremely large apertures (which are difficult to fit onto a rocket) or b) extremely small wavelengths (the atmosphere is opaque to ultraviolet light lower than a certain limit). However, if the satellite takes many, many photos of the same thing from different angles, number-crunchers with fancy algorithms can create a synthetic aperture to get around this problem. Unfortunately, this means much greater latency, and the requirement that whatever you're spying on stand still for many hours, something most people can't be relied on to do. If a large flock of satellites ganged up and all snapped a photo at the same time, they could pool their data and give an image fairly quickly, but that would be extremely, extremely expensive.--Joel 23:20, 27 September 2005 (UTC)
Would the satellites/cameras all have to be in different positions? Wouldn't a bunch of cameras on one satellite or even just one camera taking several shots be enough? I've wondered about this with ordinary cameras. If you take one shot the grain is the result of the resolution of the sensory chip or film used. If you take a series of shots, all slightly moved (which will automatically happen if you hold the camera in your hand) and you lay those images over each other (compensating for the movement, which will therefore have to have been measured) then the pixels will mostly only partially overlap. So one spot that's much smaller than a pixel will be measured in different ways, from which one may calculate the value for that spot as if one would have had a smaller pixel capturing that spot. It's sort of like a Very Large Telescope array. There the telescopes are not in the same position, but considering the distance to what's measured compared to the distance between the telescopes that hardly seems relevant. Another reason for getting not so sharp an image would be imperfections in the lens, but then that could be solved by using different lenses (ie different cameras). Part of me says this makes sense and another part of me says it's complete nonsense. Can someone make me whole again please? :) DirkvdM 19:47, 28 September 2005 (UTC)
But imagine you're a spy agency with no oversight, and can afford a CCD with unlimited resolution: eventually, the other components will impose resolution limits. I think the "different place" part is actually necessary once the aperture, rather than the sensor, is what limits your resolution. In this case, the aperture shouldn't overlap too much with where it was before/with the other aperture, but recording the difference in perspective isn't absolutely necessary, as it could also be calculated as part of the process of combining the images. But you can never put a sattelite in exactly the same place twice anyway. Geosynchronous sattelites are an apparent exception, but there's still some wobble involved. Part of the reason large arrays of radio telescopes are necessary is the huge wavelengths found in radio, compared to visible and to practical aperture sizes. I think perhaps several pictures from "the same place" could be combined to boost resolution when the CCD is the limiting factor, but it would take a different sort of math as far as I know.--Joel 16:58, 29 September 2005 (UTC)
And would that math then be complicated? Suppose I'd take several shots in rapid succession (all shifted slightly like I said), then shouldn't it be possible to write a computer program that combines them to a sharper image? (even if that would take my computer all night, it would still be handy for some photos like night shots (preventing blur)). DirkvdM 19:54, 29 September 2005 (UTC)
Yes, it appears to be quite complex. Do a Google search on "optical aperature synthesis" and see what you can find...--Robert Merkel 05:55, 30 September 2005 (UTC)

A few years ago, I saw an image taken from a satellite, of a little boy in his back yard, looking up. The boy was the son of one of the NASA scientists, and the scientist had told his son what time to walk out into the back yard and look up. The image was very clear, and the boy's face was perfectly visible and identifiable. User:Zoe|(talk) 05:52, 1 October 2005 (UTC)

cascading pareto chart[edit]

hematology[edit]

so wot's yer bloody question?

standards in wiring[edit]

What is the purpose of standards in wiring?

largely so that other electricians than the one who installed it can go in and quickly be able to figure out how it works. Also, so that devices made by different manufacturers will be compatible with one another. -Drdisque 02:49, 28 September 2005 (UTC)

Safety is also an issue.

.9999… = 1?[edit]

How does point nine repeating (.9999…) equal one?

1-0.99… = 0.00000000… There are several other nice proofs, but I'm not sure if we have an article on the matter. I'm sure someone else can help you with that though. --fvw* 03:24, 28 September 2005 (UTC)
One way to see this is to observe 1/3 = .333..., so .999... (which is clearly 3 times .333...) must be the same as 3 times 1/3. Another way is to convert it to a fraction. Let X=.999..., then 10X=9.999..., and 10X-1X = (9.999... - .999...) = 9, so 9X = 9, i.e. X=1. If none of these do it for you, you might try the explanation at http://mathforum.org/library/drmath/view/55746.html. -- Rick Block (talk) 03:34, 28 September 2005 (UTC)
Actually, we do have an article on this: Proof that 0.999... equals 1 --Pidgeot (t) (c) (e) 12:14, 28 September 2005 (UTC)
From a no-equations-involved standpoint, we know that there are infinitely many numbers between any two distinct numbers on a number line. Now, what form would a number take to be greater than 0.9999... and less than 1.0? No such number exists, therefore 0.9999... and 1.0 are not distinct (that is, they are equal). — Lomn | Talk / RfC 13:27, 28 September 2005 (UTC)
Use a calculator to square the square root of 2 and deduct 1. This will confirm that 1 is 0.9999.... ;-) Shantavira 17:22, 28 September 2005 (UTC)
For the hapless reader that doesn't reallize the above is a joke, see round-off error and the field of numerical analysis that studies that kind of thing. - Taxman Talk 18:40, 28 September 2005 (UTC)
It basically follows from the completeness property of real numbers. Read the properties section of that article if you really want to dig into the gory stuff. Our article doesn't use the infimum and supremum language I learned in advanced calculus, but that was a while ago and I forgot the completeness formulation in those terms. Those articles cover the basics. - Taxman Talk 18:40, 28 September 2005 (UTC)
Aren't natural numbers and rational numbers mixed up here? I suppose one might argue that 0.99999.... equals 1.00000.... . But 1 (without a decimal dot) is a natural number and 0.9999.... might come infinitesimally close to that, but never reaches it. So for all practical purposes they're equal, but mathematically they aren't. Right? DirkvdM 21:04, 28 September 2005 (UTC)
Again, see the article, but to summarize, any two unequal real numbers (reals) have an infinite quanitity of reals between them. What reals are between .99999... and 1? Superm401 | Talk 21:45, 28 September 2005 (UTC)
0.999... can only be defined in terms of the limit of a series. The series is in the rationals, and it converges to a natural number, 1. That's it. One important fact you need to know is that there are no infintesimals in the theory of real numbers. There are some funky theories you get in logic courses that have infintesemals, and you can do stuff with them instead of limits; I don't know how you would define 0.9999.... in that scheme, but it's irrelevant anyway. -- SCZenz 21:57, 28 September 2005 (UTC)
It is also important to note that 0.999... is a number, not a process. There is no "getting closer", 0.999... is a number, period. In calculus you will learn that decimal numbers are compact representations of infinite series, and that the series represented by 0.999... converges to its limit, 1. Here again, "converges" is a static property, not a process. Vonspringer 04:21, 4 October 2005 (UTC)

One more way of looking at it: a real number is, by definition, not simply a sequence of decimals (in which case 1 and .999.. would be distinct numbers), but actually equivalence classes of sequences of decimals, where two sequences are the same if one has all 9s as its final digits and matches the other in all the other digits before the 9. The reason for wanting them to be the same is because the associated geometric series will converge to the same number. But of course that's not rigorous. You need to define the reals before you can discuss convergence of series, otherwise you'll have no guarantee of convergence to any number (the reationals are not complete). So the rigorous answer to your question, "why are the numbers the same?", is simply "because they are defined to be the same". -Lethe | Talk 16:21, 3 October 2005 (UTC)

severe hypoglycemia[edit]

How can I view a unix manpage in Microsoft Windows?[edit]

How can I view the unix manpage <http://ccdoc.sourceforge.net/downloads/ccdoc.man> in Microsoft Windows? Masatran 07:24, 28 September 2005 (UTC)

You can download Cygwin and install it. When done, save the file to the man directory and a man ccdoc should be enough, or download and compile the ccdoc source (again, in Cygwin).
Afterwards, you can add the bin directory of your Cygwin installation to your path to be able to read the man page without having to enter bash every time. --Pidgeot (t) (c) (e) 09:37, 28 September 2005 (UTC)
Also try looking for programs to convert manpages to something you can read [8] Ojw 21:25, 30 September 2005 (UTC)

BEARD GROWTH[edit]

our forefathers ,most of them atleast, who originated from primates stopped using their tail which eventually led to most of the tail missing from the present day human.on the same logic with extensive shaving off of the beard since ages, why is it that it has not stopped growing? thanks. vinod.--219.65.45.74 10:27, 28 September 2005 (UTC)28/9/2005 1600h

  • because that doesn't have much to do with evolution, you should get better teachers.. also human population growth is exponential, that means at some point, we break the evolutionary mold, in shorter words, we're an evolutionary dead end, much like the neanderthal, and you know what happened to that guy--205.188.117.71 03:54, 29 September 2005 (UTC)
It isn't enough that something not be useful for it to evolve away, it needs to have a detrimental effect. (See vestigial organ) A tail has muscles, bones, etc that need maintainance (and maybe get in the way for certain types of walking). I don't think a beard takes much of the body's resources to make. And I imagine that shaving has been in practice for a very tiny fraction of the time that not-using-one's-tail has. Frencheigh 10:38, 28 September 2005 (UTC)
"stopped using their tail which eventually led to most of the tail missing". No, it didn't. That is similar to the evolutionary theory of Lamarck, which has been disproven. Lamarck believed(among other things) that use of organs would cause them to grow while disuse would make them shrink. Again, this is not correct. Evolution occurs through natural selection(or "survival of the fittest"). In summary, all individuals pass traits(phenomes) to their children through genes. Those individuals that are most successfully adapted will be more likely to reproduce, as well as likely to reproduce more. Therefore, more descendants will have their phenomes and genes than those of the less successful individuals. Eventually, only the descendants with the superior adaptations survive, forming new species. Genes are modified through mutation. Superm401 | Talk 21:59, 28 September 2005 (UTC)
I aggree that, in proper terms, great apes stopped having (noticeable) tails, which then prevented us from using them. One thing to note is that, for an individual creature, disuse of certain organs (especially bones and muscles, as mentioned above) causes them to atrophy. This change doesn't propagate to new generations, but it is an easy-to-observe exampe of organs shrinking with disuse.--Joel 19:12, 3 October 2005 (UTC)

There are many evolutionary explanations for the distribution of human body hair. Some are plausible; some seem like just-so stories. alteripse 11:26, 28 September 2005 (UTC)

The important thing to remember is that, as long as we can shave/pluck/wax/depilate with reasonable safety and convenience, there will never be any evolutionary pressure against hair growth. We've been able to shave since the stone age, and to pluck at least since the bronze age, although, as noted above, that's extremely brief in evolutionary terms. --Joel 19:12, 3 October 2005 (UTC)

What is sirolimus[edit]

See sirolimus. The fastest way to find information and articles in Wikipedia is to use the Search box on the left side of your screen. TenOfAllTrades(talk) 16:19, 28 September 2005 (UTC)

multiple sclerosis[edit]

I'm not sure what your question is. See our article on multiple sclerosis for lots of information on that topic, however. TenOfAllTrades(talk) 16:19, 28 September 2005 (UTC)

hydrogen bonding[edit]

there are two types of hydrogen bonds.(1)intermolecular (2)intramolecular.amongst these,which one is more strong and why?

By any chance, was intermolecular forces supposed to read as Van Der Waals forces ? you may as well post the entire problem, I could use some practice with my differentials--205.188.117.71 03:51, 29 September 2005 (UTC)
According to Hydrogen bond, it's an intermolecular bond. So I assume that the intramolecular case you refer to would just be an "intermolecular" bond between two atoms that happen to be far apart in the basic covalent structure of the same molecule (contributing, e.g. to protein folding). That being the case, I would expect the two cases to be of equal strength if all else is equal. -- SCZenz 15:43, 28 September 2005 (UTC)
Please refer to the top of this page, and note that Wikipedia isn't here to answer your homework questions. TenOfAllTrades(talk) 16:16, 28 September 2005 (UTC)
On the bright side, if that was a homework question, what I said almost certainly wasn't the answer the instructor was looking for. ;) -- SCZenz 17:30, 28 September 2005 (UTC)

Cephlapods and regeneration[edit]

Can a squid or an octopus regenerate tentacles if one is severed?

  • "the squid's tentacle would not grow back "[9] Samw 21:56, 30 September 2005 (UTC)

Wikipedia Problems??[edit]

I have noticed when i try to edit a post, i have to click on the "Edit" button for the post above. Has anyone else noticed this? Or is it just me?

This sometimes happens when a section header is not formatted correctly. Fixed (I think). --hydnjo talk 01:47, 29 September 2005 (UTC)
I think the poster is thinking as I did at first, and assuming a section's edit button is the one that follows the text. In fact a section's edit button is the one on the same line as the section's title, above the horizontal rule that preceeds the text; not the one that sitting there, temptingly, right where your addition will go. I found this counter-intuitive. And for long sections the edit button has scrolled off-screen. Sharkford 14:38, 30 September 2005 (UTC)
I believe the same problem occurs when headers are commented out -- don't know whether this is fixed or not. Dysprosia 22:23, 3 October 2005 (UTC)

Lord Ned[edit]

Lordned 17:39, 28 September 2005 (UTC)

The section edit link in the default skin is to the right of and just slightly above the section title. This can make it look as if the link applies to the previous section, when it does not. This is, I'm afraid, just soemthing you need to get used to. DES (talk) 17:53, 28 September 2005 (UTC)
On related issues, you delete a duplicate section by editing the whole page and removing it, or by editing one of the duplicates and deleting the entire contents, including the section header. I did this for your duplicate post. Also when you start a line with a space character it produces a fixed-font, un-wrapped, boxed text. This is usually not what is desired. Do indents by starting the line with one or more colons. It is not standard on wikipedia to indent the first line of a paragraph. DES (talk) 17:53, 28 September 2005 (UTC)


Ok, Thanks. When i went to try and edit the post, i click on the wrong edit "Opps"

That happens. Alos on discussion pages (like this one) it is a good idea to sign your comments with four tildas (like this ~~~~). DES (talk) 18:01, 28 September 2005 (UTC)
One more note; sometimes if there are multiple images stacked up next to an article, it will cause flaky behaviour of the [edit] boxes. None will appear next to one or more sections, and they will all pile up ([edit] [edit] [edit]) next to a later section in the article. TenOfAllTrades(talk) 18:39, 28 September 2005 (UTC)

he he... lol."::One more note; sometimes if there are multiple images stacked up next to an article, it will cause flaky behaviour of the [edit] boxes. None will appear next to one or more sections, and they will all pile up ([edit] [edit] [edit]) next to a later section in the article" thats one big problem...

63.199.33.66 16:38, 29 September 2005 (UTC)

puna multa[edit]

Dear all. I am trying to find out any information about "puna multa" which should be the name for a traditional finnish (scandinavian?) type of timber treatment based on natural whiting and rye flour. Please if you find any info let me know at (E-mail address removed). Thank you.

Hmmm. A number of links come up in Finnish when I Google that phrase, but my Finnish is, um, limited :) You might try asking one of the people listed at the Finnish Wikipedia Embassy if they can help you. --Robert Merkel 04:26, 29 September 2005 (UTC)
The word is properly spelled punamulta, and translates literally as "red dirt". It's a traditional type of red paint made of water, rye flour, iron sulphate, linseed oil varnish and Egyptian rouge, a natural red pigment consisting of hematite or iron oxide rich clay. —Ilmari Karonen 18:07, 25 October 2005 (UTC)
The paint is also used in Sweden, where it is called rödmull. A particularly well known variety is Falu red, named after the source of the pigment, a copper mine in Falun, Sweden. —Ilmari Karonen 18:18, 25 October 2005 (UTC)

Bad hurricane cycles[edit]

I was once told that every 40-43 years, a major hurricane strain happens. Is this true? If so, are the years correct?

Check our article on hurricanes; specifically, the "long-term trends in cyclonic activity" section. There is a very approximate estimate of a 50-70 year cycle for the Atlantic basin, though full-ocean coverage has not existed long enough to make a firm statement in that regard. — Lomn | Talk / RfC 20:15, 28 September 2005 (UTC)

hydrogen peroxide[edit]

Has an article here, if you, in fact, wanted to learn something about it. Not to pour salt in your wounds, but if you need something specific (that's not already in the cleverly hidden article), perhaps you should ask a question. ByeByeBaby 19:48, 28 September 2005 (UTC)

quantitative methods and physical planning[edit]

how do these quantitative methods help in the physical planning field?

Which quantitative methods? Chuck 20:35, 28 September 2005 (UTC)
I'll guess it's a follow-on to a homework question that the original poster should do himself. — Lomn | Talk / RfC 20:54, 28 September 2005 (UTC)

Lagrange Minimization procedure[edit]

Since you know how to frame the Section header as "==Lagrange Minimization procedure==" then please follow up with an actual question. Wikipedia is not a search engine. --hydnjo talk 00:00, 29 September 2005 (UTC)
Actually, someone using the "add a new question" link at the top never uses wikiformatting to create the header. However, the above is correct -- this is not a search engine. However, this link over in Miscellaneous may help out. — Lomn | Talk / RfC 02:16, 29 September 2005 (UTC)

Epidemics indiana 1850 - 1860[edit]

Since you know how to frame the Section header as "== Epidemics indiana 1850 - 1860==" then please follow up with an actual question. Wikipedia is not a search engine. --hydnjo talk 00:00, 29 September 2005 (UTC)

indiana[edit]

Hey, I live in Indiana! You might want to review the instructions at the top of this page, particularly the part that says "Questions are answered by humans, not computers. This is not a search engine." Chuck 22:21, 28 September 2005 (UTC)

PEANUT SKINS[edit]

ARE THEY GOOD FOR YOU TO EAT? JANET F.

Assuming that you don't mean the "shells" (the hard outer part that we usually throw away) but rather the thin, maroon colored "skin", I'd presume that they aren't bad for you to eat or they wouldn't be so readily available that way, but I suppose that same answer would apply to the hard outer shell as well! Also, the "meat" within called the peanut are OK for some folks and deadly for others. So, I have no idea if they "ARE THEY GOOD FOR YOU TO EAT? JANET F.", that's between you and your doctor. I can only tell you that they are not bad for me to eat. --hydnjo talk 00:25, 29 September 2005 (UTC)
If I had to guess, I'd say that they're not harmful. (I'm making the same assumption as Hydnjo does about what constitutes the 'skin'.) I suspect that they're loaded with insoluble fibre, which is good for your digestion. On the other hand, I find them a bit bitter and kind of dry, and they can cause an unpleasant tickle in the back of my throat when I eat them.
Ah; Google is your friend. An interesting link here. Apparently peanut skins are used as animal feed–suggesting that they're not harmful. It seems that they contain a number of useful fatty acids, too. TenOfAllTrades(talk) 01:44, 29 September 2005 (UTC)

what is a cell?[edit]

"Cell" can have many different meanings, depending on its context. Have a look at Cell and see which one you are interested in. Chuck 23:29, 28 September 2005 (UTC)

wonderland[edit]

who is the blue ferry?

Although this is when rather than who, I hope this is of some help. --hydnjo talk 00:31, 29 September 2005 (UTC)
Perhaps you mean the Blue Fairy, from the novel Pinocchio, who also features in the movie A.I.: Artificial Intelligence.-gadfium 03:45, 29 September 2005 (UTC)
Was there a furry in the "blue" (i.e., pornographic) version of Alice in Wonderland? I never saw it, but I would assume there was. If so, the credits would tell you who played what role.--Joel 19:26, 3 October 2005 (UTC)

What day is the North Pole tilted furthest from the Sun?[edit]

whatever day is the middle of winter in the northern hemisphere Jeremybub 02:46, 29 September 2005 (UTC)

On the winter solstice, which is usually December 21, but can vary by up to a day (depending on leap year adjustment). Shantavira 08:58, 29 September 2005 (UTC)

What is the act of using your senses to view the world? 11 letter word[edit]

How about "observation"? --jpgordon∇∆∇∆ 02:52, 29 September 2005 (UTC)

Are we solving crossword puzzles here now? DirkvdM 12:49, 29 September 2005 (UTC)

Feces and foot[edit]

I just stepped barefoot on what appeared to be human shit in an urban alleyway in the Eastern United States. I was quick and enthusiastic with the soap and the water, but I am still concerned about infection risk. Contributing to my concern are that I have a three-day-old cut on the soul of that foot and that there was next to the shit what in the dim light of the alley could have been a spoonful of jam or an enormous clot of blood. I didn't step in this second substance, but am thinking that neither dropping blood clots nor shitting in alleys are signs of health on the part of this mysterious person with whom I have suddenly become so intimate. Am I in danger? Are there any symptoms I should watch for? Thanks — Pekinensis 03:26, 29 September 2005 (UTC)

  • Pekinensense,

I would contact your doctor as soon as you are able. It is probably best to be safe than sorry in these circumstances. Capitalistroadster 04:11, 29 September 2005 (UTC)

Have you been vaccinated against Hepatitis B? If not, this is something to bring up on that doctor visit. - Nunh-huh 06:37, 29 September 2005 (UTC)
And, if you haven't already, clean the wound and disinfect it with something like iodine (the most common brand name solution is called "Betadine" as per normal first aid procedures. --Robert Merkel 04:21, 29 September 2005 (UTC)

Relax. You have already taken care of it with soap and water and your injury was more aesthetic than biological. But what the heck were you doing barefoot in a dim alley? alteripse 09:55, 29 September 2005 (UTC)

Thank you all for your answers. I've decided not to worry about it. I have been immunized for Hepatitis B. What was I doing? I was taking out the trash and thinking about February when I stepped in the same substance in the same place, and that the Universe would not be so perverse as to repeat such an incident when I happened to be barefoot. Thanks again. — Pekinensis 16:45, 2 October 2005 (UTC)

Elemental lithium[edit]

I have searched the Internet for a while now, and cannot find the answer to this question:

How much elemental lithium is in 300 mg of lithium carbonate?

I know, for instance, that 120 mg of lithium orotate contains 4.8 mg of elemental lithium. I need this information for comparison sake, as I run a Yahoogroup of people taking -- or switching to -- lithium orotate.

Sincerely, Gerald L. "Moss" Bliss, D.D. ALT-therapies4bipolar Yahoogroup

According to our article on lithium salts, the chemical formula of lithium carbonate is Li2CO3. That there's one carbon and three oxygen atoms for every 2 lithium atoms in lithium carbonate.
From our entries on lithium, carbon, and oxygen the atomic mass of each is 6.974, 12.0107, and 15.9994. From this, we can calculate the fraction of the compound that is made up of lithium is:
\frac{2 \times 6.974}{2 \times 6.974 + 12.0107 + 2 \times 15.9994} \approx 24\%.
Therefore, 300mg of lithium carbonate would contains about 72 mg of elemental lithium.
Please note that Wikipedia does not give medical advice, and that incorrect dosage calculations are a regular cause of avoidable deaths in hospitals. So, whatever you do, please don't start dosing yourself purely on the basis of some quick calculations of somebody who hasn't done chemistry since high school.--Robert Merkel 04:15, 29 September 2005 (UTC)
To illustrate the problem, that equation should be
\frac{2 \times 6.974}{2 \times 6.974 + 12.0107 + 3 \times 15.9994} \approx 18.86\%
or 56.5 mg lithium for 300 mg lithium carbonate. Be aware as well that the bioavailability of metal ions is different for different salts. Physchim62 09:10, 29 September 2005 (UTC)
Whoops! I wasn't trying to illustrate the point, but hopefully people will take notice of the warning now that I've demonstrated how easy it is to screw up! --Robert Merkel 12:27, 29 September 2005 (UTC)
Our article on lithium orotate is not referenced, so it is subject to even more caution than usual. It may or may not give you some ideas to compare the two treatments. You may well wish to ask yourself why the FDA does not approuve this treatment (or, even better, ask them and tell us why!). Physchim62 14:15, 4 October 2005 (UTC)

are the stars we see in the nights sky actually suns[edit]

They are actually stars, and the Sun is a star. Many of the stars are just like the sun, though some are much bigger, much smaller, or otherwise different. Some people, especially science fiction writers, do use the word "sun" (not "Sun") to refer to other stars, but to avoid confusion it's best to stick to "star". Notinasnaid 07:54, 29 September 2005 (UTC)

Except the Morning Star and Evening Star. -guety is talking english bad 14:53, 29 September 2005 (UTC)

suns and stars[edit]

Are the stars we see in the nights sky actually suns? and are there any other suns in our galaxy that is equal or higher in size as our own sun? Africadeedee

Yes, almost all of them are, except a very few might be planets. There are lots of other suns in our galaxy which are as big or bigger than our sun, but there are even more which are smaller. The smaller ones are usually dimmer, so the ones you can see are mostly the larger ones. See our article on stars for more details. If you find that article is too complex for you, then look at the Simple English article on Stars.-gadfium 05:32, 29 September 2005 (UTC)

Nuclear blast in eye of hurricane..[edit]

What would happen if someone detonates a nuclear device inside the hurricane eye. Will it disperse the hurricane system, nothing happen, or just something else will happen? What if they used the Soviet Era 'The Czar' super-sized H-bomb. Does it even matter if the device is detonated inside the eye, outside of it (near the clouds spur) or even an airblast above the hurricane system ? Thank you very much in advance.

bukhrin

I don't think anybody's ever asked before, though you probably could do a simulation if you had access to weather-forecasting computer code. One side effect that's easy to predict is the distribution of dangerous nuclear fallout over a wide area, which could render places in its path uninhabitable for years, perhaps even decades, afterward. --Robert Merkel 07:47, 29 September 2005 (UTC)
though you probably could do a simulation if you had access to weather-forecasting computer code. Don't forget to budget for several days on the nearest supercomputer. :)--inks 12:18, 29 September 2005 (UTC)
It would probably not do much to disrupt the hurricane. The energy in a hurricane (see [10] for example) is several orders of magnitude greater than the yield of existing nuclear bombs. Fredrik | talk 11:01, 29 September 2005 (UTC)
Interesting experiment though. A FAE (Fuel-Air Explosion) approaches the strength of a Nuclear Weapon by purely chemical means, so if this were done there would be no nuclear fallout from it.
They only approach the yield of the tiniest nuclear weapons, though. --Fastfission 16:03, 29 September 2005 (UTC)
I doubt it would do anything at all. Even a Tsar Bomba sized blast pales in the overall, cumulative energy present in a hurricane. If you look at our entry on kiloton you can see how much more raw energy natural phenomena has in general (the reason that the bombs seem so big, of course, is that they release all of their energy into a relatively small space and over a very small amount of time). --Fastfission 15:36, 29 September 2005 (UTC)
The NOAA answers this question in their Hurricane FAQ. — 15pxmendel 17:08, 29 September 2005 (UTC)
  1. Delivering a nuke to the eye of a storm would require some fancy footwork, missile technology not something that your average troublemaker might have in the near term.
  2. Do Google search ... there are places where you key in geographic location and how big some event to see damage from WMD, giant meteor strike, earthquake, other disasters.
  3. Watching on TV news huge traffic jam of people evacuating at last minute, it occurs to me we are kind of asking for trouble, since this goes on TV news world wide to all kinds of audiences.
    1. major hurricane is coming, approx where, announced days in advance
    2. local leaders take forever to discuss the implications of what is obvious to everyone, who knows anything, such as
      1. here comes category 4-5 and the flood control is only designed to handle category 3, and the city is under sea level, so after landfall it will be under water
    3. during that predictable time frame when the local leaders cannot decide what to do, terrorists blow up major escape highways with conventional explosives, stockpiled in geographic areas where the Atlantic hurricane season is known to be active.

AlMac|(talk) 19:12, 29 September 2005 (UTC)

To paraphrase NOAA:

  • Before implementing this plan, you have a hurricane to deal with.
  • After implementing the plan, you have a hurricane and a nuclear explosion.

Ojw 18:50, 1 October 2005 (UTC)

migraines[edit]

how to improve migraines[edit]

  • Our Migraine article contains extensive information on migraine treatment. Your doctor will probably be able to advise of treatments if you suffer from them. Capitalistroadster 08:09, 29 September 2005 (UTC)
  • Improve them? Few sufferers want them to get worse. Cure them perhaps was what you wanted to ask about. AlMac|(talk) 01:15, 30 September 2005 (UTC)
I hear that Oliver Sacks finds his migraines to be quite entertaining, like a light show. I'm not sure modern medical science has found a way to turn ordinary sufferers into Hildegard of Bingen, but perhaps this person is looking for a way to improve the head trip.--Joel 19:39, 3 October 2005 (UTC)

how wind blows?[edit]

Is it because of earth's revolution or change in air density due to sun light?

Have you tried reading our article on Wind? There should be some information there. From what I can ascertain, there are a variety of types of wind that have different causes.. but you should definitely read that article. splintax (talk) 08:42, 29 September 2005 (UTC)
All wind is fundamentally caused by pressure differentials. Many factors affect that pressure, and the differing linear speeds(though constant angular speed) of rotation at different latitudes affect apparent direction. See also "Why does wind gust?" above. Superm401 | Talk 13:59, 29 September 2005 (UTC)

construction technology of rotating buildings[edit]

could you please show me the details and sections of rotating buildings?? and if possible the criteria etc too to implement it. 2nd year student, amrita

Several cities have restaurants on top of high buildings, in which only the top rotates. You sit at window seat, and in an hour it has rotated so you get to see the whole city. I have never heard of an entire building rotating. AlMac|(talk) 19:15, 29 September 2005 (UTC)
Glasgow Science Centre does. Or was supposed to, anyway. Notinasnaid 22:22, 29 September 2005 (UTC)
The largest and most numerous rotating buildings would probably be radio telescopes. I think they use circular tracks, along which a motor on the outside of the building travels. Ojw 19:47, 1 October 2005 (UTC)

mobile phone[edit]

Hi,

my question is "why mobile phones are not allowed in petrol bunks?

Bharathi.

  • Some people believe the static electricity create when a mobile phone is used could cause an explosion which would be detrimental near petrol. However, the Mythbusters tried to cause an explosion using mobile phones and couldn't succeed unless they purposely created loads of static electricity (far more than a phone could generate). Still, there have been accounts of faulty and exploding batteries in phones which could still cause problems near petrol. Hope than answers your question. - Mgm|(talk) 11:01, 29 September 2005 (UTC)
I'm not satisfied with their test, actually: they didn't set the phone to vibrate. In most direct current electric motors, the commutator throws up sparks several times a second as the motor runs. But in fact, I agree that this is more a question for the "culture" section of the reference desk...one reason I'm unhappy with this recent segmentation of the project.--Joel 17:49, 29 September 2005 (UTC)
  • They did do a follow-up experiment to address multiple issues viewers brought up, but I can't remember the result. Sorry. - Mgm|(talk) 19:12, 29 September 2005 (UTC)
  • Surprisingly I found an article on MythBusters Episodes the mobile phone myth is listed in season 1 (episode 2) and season 2 (episode 14). - Mgm|(talk) 19:23, 29 September 2005 (UTC)
It failed both times. --R.Koot 10:10, 30 September 2005 (UTC)
IIRC, they didn't turn on the vibrator for the second test, either, despite all the sex toy jokes it could have sparked. Oh, well...my fault for keeping my criticism to myself the first time around. To be honest, though, I would expect the microphone holes etc. in a cell phone to be too small to allow a flame front to pass. --Joel 19:44, 3 October 2005 (UTC)

Botany[edit]

I want to know what is exactly subdiecious condition. If in a dioecious species, if the males are converting temporarily to hermaphrodites, what we can call this condition?

I believe the article for you is plant sexuality. It seems to give two answers to your first question, one more specific than the other, but both make "subdioecious" seem like a plausible anwser to your second question. — Pekinensis 13:08, 29 September 2005 (UTC)

Energy Drink Question[edit]

I was wondering if XS Citrus Blast energy drink was really made up of things that gave you energy or if it is simply caffeine with some flavor added in. Next, I was wondering if it would simply be better to just by a can of coke instead of the energy drink?

--Thanks, J

Found this using google. Active ingredients: Taurine, Caffeine, Ginseng, Vitamin B3, Vitamin B5, Vitamin B6, Vitamin B12. My guess would be that this contains more caffeine than a coke, so you need to drink less of it for the same effect. --R.Koot 16:08, 29 September 2005 (UTC)
If your diet is extremely bad, you might feel a lack of energy due to mild pellagra or some other deficiency disease, in which case XS Citrus Blast would make you feel revived beyond the sugar and caffeine...but eating a balanced diet would make you feel even better.--Joel 17:12, 29 September 2005 (UTC)

Is evolution scientific?[edit]

One of the reasons often given for not teaching Intelligent Design is that it is "not scientific", which as far as I understand means it cannot be experimentally disproven. What makes evolution "scientific", or rather what experiment would disprove evolution?

I don't think it's real at all, just another leftist conspiracy, much like... gravity, and that whole "round earth" business, If the earth is really round, and it really spins around the sun, then why don't I fall off when I'm on the bottom? Answer that smart guy--172.208.123.70 14:29, 2 October 2005 (UTC)
Evidence of evolution might be a good place to start. -- SCZenz 15:26, 29 September 2005 (UTC)
What you are referring to is the notion of falsifiability. Whether or not evolution is falsifiable depends on who you ask (creationists would probably interpret it to say no, philosophers might sit on the fence, scientists would say yes) — as a philosophical concept, it is not as cut-and-dry a test as people opposing creationism/ID usually make it out to be (though I personally think that in this instance, their overall conclusion is probably correct).. A lot of depends on whether you are taking evolution "as a whole" the entity which needs to be falsified or whether or not you are taking specific claims, and a lot of it also depends on what version of falsifiability you use. One fairly intelligent page which argues that evolution is falsifiable is Talkorigins.org: Evolution and Philosophy. --Fastfission 15:27, 29 September 2005 (UTC)
That is correct. I do not of any experiment that would disprove evolution, but that does not mean someone won;t come up with one sometime. This is impossible with Intelligent Design as you could always counter with "it was designed that way", while with evolution the theory has to modified or discarded. See Lamarckism, evolution, evidence of evolution, Intelligent Design and scientific theory for some more information. --R.Koot 15:28, 29 September 2005 (UTC)
Another way in which ID is unscientific is that it does not deal with a repeated mechanism of the natural world that operates under self-consistent rules. It just has some being who does what he feels like. -- SCZenz 15:33, 29 September 2005 (UTC)

Science restricts itself to hypotheses, theories, mechanisms, and processes that are consistent with our knowledge of the material world and explicitly excludes claims about supernatural processes or knowledge. Science cannot and does not claim that God does not exist or did not create the world, only that such claims cannot be evaluated from a scientific perspective and are not likely to advance our scientific understanding of the material universe. Since first proposed, an enormous amount of experimentally verifiable and directly observable evidence has supported the validity of the basic process of evolution and no evidence strongly undermines it. It is possible to imagine that several million years ago, several thousand years ago, or several minutes ago God created the world exactly to seem as if evolution is occurring, but none of these hypotheses fit with other scientific knowledge or seem likely to advance other scientific understanding or can be proven or disproven scientifically.

Science does not exclude the supernatural, but says that so far the supernatural does not lend itself to any scientific analysis, which is not quite the same thing. (But its so close it is the same thing for all practical purposes).

The objections that most intelligent people have with the idea of Intelligent Design are that it is (a) presented dishonestly (as not being intended to promote fundamentalist Christianity), (b) confuses people about what science is (by incorporating miracles and supernatural processes in scientific knowledge), and (c) misrepresents our current understanding of evolution (which is both dishonest and confusing). Most intelligent Christians make a distinction between evolution as a scientific way of understanding the changes and interrelationships of living things on earth, and most intelligent scientists do not claim to be able to scientifically prove or disprove the existence of God or whether he had a role in the formation or history of the universe. Does that help? alteripse 15:41, 29 September 2005 (UTC)

(adding during edit conflict with above three responses)
A scientific theory (versus just any ole theory) is one that makes testable predictions. As you intimate, a theory without testable predictions is impossible to disprove and rather useless to a scientist. So for instance, I could come up with a theory of everything that was simply a list of observed occurances: in other words a theory that simply described the way things are and said "this is how it is". That theory would not be a scientific theory, because it would make no new predicitions, not to mention being really unsatisfying as it wouldn't "explain" any observations with underlying principles.
A prof of mine once said, "every great theory swallows it's predecessor whole," meaning that for a new theory to gain ground it needs to explain all the behavior described by the old theory while making an entire set of new, experimentally testable predictions. A great example is quantum mechanics, which swallowed Newtonian mechanics whole and then made an entire set of new predictions which have been tested rather extensively. It's not complete, but it's more complete than Newtonian mechanics, so it was eventually accepted by the scientific community, which is now trying to find the next, more complete sucessor theory.
In contrast, Intelligent Design — like my first example — makes no testable predictions. It is therefore not a scientific theory and is completely ignored as a possible replacement for evolution by the majority of the scientific community.
Right now, evolution is backed by so many observations that all scientific debate in the field centers on the details, not the basic principle of evolution. I cannot therefore anticipate anyone developing a scientific theory that can explain all those observations without also having evolution at it's core. — Laura Scudder | Talk 15:43, 29 September 2005 (UTC)
(adding during edit conflict with above four responses)
Evolutionary biology is a living science which is full of falsifiable hypotheses. Every publication in systematics which overturns existing ideas about systematics disproves some idea about evolution. If existing phylogenies say that species A and species B are more closely related to one another than they are to species C, that is an evolutionary hypothesis. Now, suppose someone comes along and looks at the genetics of the two species and concludes that species A and C are closely related, and species B is more distantly related. Assuming that their data are sound, this person has disproven an evolutionary hypothesis. Another way of disproving evolution would have been the discovery of an invariant fossil record - that, no matter how far back you go, you find the same set of modern living species. If you could find modern species in hundred million year old strata, then you would have evidence to disprove the hypothesis that the species you found evolved.
It's a little like heliocentric theory - when it was proposed that the earth revolved around the sun, there was a competing hypothesis that the sun revolved around the earth. Heliocentricity was confirmed experimentally, so now someone could come along and say "this is an unfalsifiable theory". Difficult to falsify it now (although there are still geocentrists out there), because it has already been falsified. Similarly, the existence of a fossil record makes it look like evolution is unfalsifiable because there is overwhelming evidence that it has taken place. But it still remains falsifiable. Guettarda 15:46, 29 September 2005 (UTC)
Has geocentricity been fansified? As I understand it the theory works, but is just much more complicated than heliocentricity and it's customary to work sith the simplest solution. DirkvdM 19:43, 29 September 2005 (UTC)
Just a few notes: theories often don't swallow entire previous theories whole (they often decide previous aspects of theories are not longer worth paying attention to, a la Thomas Kuhn); and in this case we're not talking about falsifiability in the sense that any given result will necessarily either favor one whole theory or another (the heliocentric question is not a great example in this case, as there are no "phases of Venus" to compare it to in evolution); and lastly, one of the other reasons that scientists say ID is "not science" is because it invokes non-natural causes as explanations (i.e., it invokes the supernatural), and "science" deals only with the natural world (once you start a science of the "supernatural" world, there is no end of explanations which are equally plausible). The requirement of science to use methodological naturalism has been criticized by IDers (notably Johnson) who say that it necessarily promotes an atheistic view of the world (even though it was originally formulated by Christian scholars, mind you). None of these critics, though, have adequately (in my mind) provided an acceptable view of what a non-materialist methodology would be which doesn't immediately snowball into the possibility of introducing supernatural explanations into anything we don't understand (as a related problem, see god of the gaps). What "is" and what "is not" science is a difficult thing to determine, though, and after a few centuries of intense debate nobody has yet come up with a great way of determining such a thing (see demarcation problem). So it's a sticky issue in a philosophical sense. But most of this (on both sides) is more about politics than it is true philosophy. --Fastfission 16:15, 29 September 2005 (UTC)

re: "...what experiment would disprove evolution?" JBS Haldane famously said fossil rabbits from the Precambrian era would disprove Darwinism. David Sneek 18:07, 29 September 2005 (UTC)

There are lots of 'holes' in evolutionary theory, based partly upon inexplicable fossil evidence. But due to the fact that this evidence was created long before people were around to observe it, it is entirely possible the evidence has been corrupted in some way which is not detectable yet, or maybe ever. Take Piltdown Man as an example.
I think we have deviated from the original question significantly. The answer is yes, the theory of evolution is scientific, for that reason it remains a theory and probably will for some time as the complexity of proving it or disproving it will require a lot of modification of the theory.
Falsification is really about designing an experiment, making a prediction and checking if that holds true. So you might claim that you could create a new animal out of an existing animal. Such as a Russian experiment I once head of where over tens of years tame foxes were created by interbreeding the meekest specimens over and over again. But if something like this fails then that doesn't prove that you couldn't have make it work if you would have done it differently. The big problem here is that there are too many factors at play to design a good laboratory style experiment. Which makes it almost impossible to falsify the evolution theory (or rather too easy, which would invalidate any falsification). And it's even worse with fossil evidence. There's always the chance that you'll find an animal you can't explain. But if you only know the overall way evolution works and not all the intricacies then it's quite possible you can't think of a solution yet. But the point is that it is falsifiable (there is the possibility to find something that disproves it) and that makes it scientific.
Also, as said before, there is just too much evidence to suport it. It 'works', as proven by farmers who have bred loads of types of animals to suit their needs. And it just makes too much sense. It is hard to believe that it might not work. Offspring are on average like their parents and less adapted individuals are less likely to get offspring. Both true right? Take it from there and you get evolution. Whether this explains everything (such as the origin of life) is an altogether different matter. But that this basic form of evolution takes place is just too unavoidable not to be true. DirkvdM 19:43, 29 September 2005 (UTC)
The accumulation of previous evidence has nothing to do with whether a theory is falsified or not or replaced with another. The Newtonian theory accounted for every observation thrown its way with the exception of about three. But those three (perihelion of Mercury, Michelson-Morley experiment, and lastly the deflection of starlight around the sun) were enough to topple the whole thing for most physicists in favor of Einsteinian Relativity in the early 1910s. "Falsification" doesn't at all mean "replace with something totally difference which gives totally different answers." Young Earth Creationism will never be the answer to a falsified evolution (too many simple observations contradict its "predictions" over and over again), but that doesn't mean that the current understanding of evolution (as either fact or theory, in the Gouldian sense) is the last word in any event. --Fastfission 02:25, 30 September 2005 (UTC)
Indeed, falsification has nothing to do with whether there exists an alternative. Forgot to react to that. DirkvdM 17:32, 30 September 2005 (UTC)

AirBus 360 Questions[edit]

Does anyone rember the AirBus 360 Emergancy landing? What if when they touched down on back wheels, one (Or both) of the back wheels broke? Would it tip over, and rip the wing off, and the jet enginer blow up? Or would it just tipp and scrapte the tip, and spark? Any Ideas appreciated Lordned 16:44, 29 September 2005 (UTC)

Did you mean JetBlue Airways Flight 292, which was an AirBus 320, or this another incident? In any case, commercial airplanes always touch down on their back wheels first--if one broke, the results would be rather catastrophic, I suspect. Even less-than-complete landing gear collapse can result in ground loop, according to the landing gear article. -- SCZenz 18:11, 29 September 2005 (UTC)
Yes i did mean " Did you mean JetBlue Airways Flight 292, which was an AirBus 320" So i was off by 40... Thanks. I wonder what would happend with a stratofortress. Or a boing 747, or an A-10.... Maybe will never know.
Become an aeronautical engineeer / mechanical engineer, and you might be able to get a job simulating those kinds of events. You'd probably need a CAD design of the plane to simulate how each bit of the landing gear fails and what else it affects, rather than just using a desktop flight simulator. Ojw 21:29, 3 October 2005 (UTC)

Chemical Structure of HCl[edit]

Gah! I'm supposed to be finding the structural formula for Hydrochloric acid. Even on google, all I get is various diagrams of drugs. Help!

  • Please tell me this is a joke.. no wait, hold on, while I'm here does anyone know the chemical formula of H2O?--172.208.123.70 14:26, 2 October 2005 (UTC)
The structure of HCl is very simple, it is just H-Cl, now hydrochloric acid is a bit different as HCl needs to be dissolved in water to act as an acid, but the term structural formula is not very appropriate to that.
Have you looked at the Wikipedia article: Hydrochloric acid? --hydnjo talk 20:48, 29 September 2005 (UTC)
Hydrochloric acid is an ionic solution, meaning it consists of H+ and Cl- ions moving around freely in solution (presumably in water). As such, it has no molecular structure. If you mean hydrogen chloride gas, it's just the two atoms with a single covalent bond: H—Cl. --David Wahler (talk) 13:59, 30 September 2005 (UTC)

Mallard Duck[edit]

I was told mallard ducks lay from 8 to 13 eggs before they start incubation. My duck has laid 19 eggs and shows no signs of incubating them. How long can the eggs survive and will she ever incubate them? Thank You

Mallards are wild birds. But farmyard domestic ducks are bred from Mallards, and can look similar. Farmyard ducks have been selectively bred (1) to lay more eggs (makes more money for the farmer) and (2) to ignore their eggs after laying (so the farmer can collect them up, and so as not to waste time that the duck could spend laying yet more eggs). So I suspect your bird is a farmyard duck. If you want to hatch the eggs, you will need to buy an incubator and become a poultry farmer. MPF 21:26, 29 September 2005 (UTC)
On the other hand, it might just be simpler to make some omelettes. ;-) Shimgray | talk | 21:34, 29 September 2005 (UTC)

Portable Application Environments[edit]

What are Portable Application Environments? How about mobile computing systems? What would you need to know to be a software programmer in these fields?

Thanks! James

This ZDNet article (which is the first result that came up in a Google search) explains that portable application environments are, essentially, an API that can be implemented to run on multiple operating systems and architectures. The Java programming language and its associated bits are the best known example, while the Microsoft .NET environment is another (along with a compatible open source project, the Mono development platform).
I assume that mobile computing systems refers to developing software for personal digital assistants and advanced mobile phones.
To become a professional software programmer in this field, like other types of programming, you should ideally go to college and do a degree in software engineering or computer science. To get experience in these specific portable application environments , you can download basic development tools for at least Java and Mono for free, and start learning them yourself. If you own a PDA or some mobiles, you can download development tools for them, too, and start experimenting with programming on them.--Robert Merkel 22:59, 29 September 2005 (UTC)
There's good theory, and there's real world.
I have not yet learned how to draw pretty pictures in Wiki like so many other people do.
Draw a triangle and at each apex place a word
Quality
Features
Speed to Market
These are the goals of anyone developing software for any market ... you want good stuff, interesting stuff, and get it out there before competitor companies get their stuff to market. In recent years quality has been sacrificed for the other two. Examples of quality is good security, not at risk of viruses malware, personal privacy not at risk of being violated, it doesn't break with stupid error messages.
Who is General Protection Default & why is the military interested in messing with my computer? <G>
Thus if you apply for a job at some company that wants to compete in this field, perhaps they not care about quality either, just cool features, rapidly developed. AlMac|(talk) 03:26, 5 October 2005 (UTC)

where is ghana ?[edit]

  • See Ghana, which has a location in the first line and a nice clear map. Shimgray | talk | 21:22, 29 September 2005 (UTC)

Hybrids and percentile differences in DNA[edit]

What is the percentile difference in DNA between Horses and Donkeys?

For two species to hybridize what is the minimum percentage of DNA that they must have in common? Or does it vary based on the complexity of the organisms?

What is the greatest percentile difference bewteen DNA in Humans?

p.s. How do I watch just my question? --RPlunk 22:17, 29 September 2005 (UTC)

I do not believe you can put your question in Wiki watch list. Here is how I watch my question(s) (only one so far):
  1. Post the question hopefully correctly.
  2. Get to table of contents and use that to link to the question.
  3. The url is now just of the question.
  4. Use my browser to capture this place to return to at a later date or time.
  5. Do so.

AlMac|(talk) 01:19, 30 September 2005 (UTC)

IANAB, but you might want to look up the major histocompatibility complex...it seems that not all DNA is created equal, when it comes to reproductive viability. --Joel 19:51, 3 October 2005 (UTC)

who was galileo?[edit]

  • Who was he?? A heathen I say!!! Spouting heracy about the sun not rotating around earth!!! I'll believe that when I see it.....dirty revolutionists, gravitaion is JUST A THEORY!!!!!!!--172.208.123.70 14:24, 2 October 2005 (UTC)
If you try typing "Galileo" into the search box on the left of this page, and had clicked "search", the very first link is to Galileo Galilei, the subject of your question. --Robert Merkel 22:42, 29 September 2005 (UTC)
Should there be a template for this sort of response? ;) -- SCZenz 22:53, 29 September 2005 (UTC)
I was going to create one which had the format of {{seearticle|Galileo Galilei}} but the amount of coding there is really not much less than "See our article on Galileo Galilei". Plus, we'd lose an opportunity for snarky comments! --Fastfission 23:44, 29 September 2005 (UTC)
But we could put a snarky comment in the template, and make the same one every time! Wouldn't that be fun? -- SCZenz 00:28, 30 September 2005 (UTC)
Create a special 'insult of the day' template that changes each time you view it -- that way you can spend your time coding MediaWiki instead of working at the reference desk. Ojw 21:16, 30 September 2005 (UTC)
For technical matters, you can crib off of the stub template from Uncyclopedia, but I'd prefer it if the humor itself came from in-house. They have a pretty slick setup, with a random result every page load. --Joel 20:08, 3 October 2005 (UTC)

Seizure Trigger?[edit]

In my psychology class today, while the prof was lecturing about seizures and the brain areas that cause them, another student actually experienced a seizure. Those around him began to call for help and the prof had someone call an ambulance. What I would like to know is whether or not such episopdes can be triggered simply by the discussion of the disorder, or if the lecture and the actual seizure could in any way be related. The prof was not showing any multimedia sequences when the event occured. Thanks

Seizures are not triggered by discussing them, but pseudoseizures can be. alteripse 01:16, 30 September 2005 (UTC)

Peer-to-peer wiki?[edit]

Would it be technically possible to develop something like a wiki on a peer-to-peer basis? I am thinking of the vulnerability of wikis to censorship, particularly the Chinese Wikipedia, which has been blocked in the past. I am not proposing anything, just wondering whether it would be possible. Thanks.--Pharos 22:58, 29 September 2005 (UTC)

Yes, it is certainly possible, but who's to stop the censors from blocking the place to download the client from? -Drdisque 00:45, 30 September 2005 (UTC)

Technically possible? Sure. Easy? Not so much. The file sharing peer-to-peer programs (like kazaa or Napster) solve a problem closer to traditional web servers which is distributing the same content to lots of users. Rather than music or video files something like these programs could easily distribute static web pages. The question these sorts of clients throw out to the distributed network is basically "does anyone have a copy of <x>"? All the copies are presumably identical, so if any peer has a copy it's good enough. The essence of a wiki is that the web pages are writable as well as readable by anyone. This makes the question that would need to be thrown out to the distributed network "who has the most recent copy of <x>"? The naive peer-to-peer way to do this requires asking everyone in the network, which would not be feasible for anything except a trivally small network. The trick would be to allow the question to be answered without explicitly asking everyone in the network. If there aren't any centralized servers keeping track of all the content and who has what, I think this is at least a reasonably difficult problem. -- Rick Block (talk) 01:25, 30 September 2005 (UTC)
Aside from the problem of efficiency, there's also the question of security and vandalism prevention. There's nothing to stop anybody from setting up a peer which replaces every page in the wiki with spam and always distributes it as the most recent version. Perhaps you could set up some sort of dynamic, voting-based blacklist but it's not likely to be very easy. --David Wahler (talk) 13:51, 30 September 2005 (UTC)
How about this: everyone keeps a database of which page was edited when. Updates on this get syndicated to everyone. Everyone keeps a running copy of N articles, and subscribes to the diffs (which they request by watching the database and asking "anyone have that new update to WP:RD from 13:51, 30 September 2005? I think my copy is out-of-date." The system is set up so that at least M copies of this article are maintained, and during off-peak hours, the copies are compared and rectified, by majority rule. Especially if archive distribution (i.e., who keeps what article) is random, and if M is fairly large, this would seem to make vandalism more difficult than it currently is for Wikimedia. This seems plausible to me, but ianane (I am not a network engineer). Feel free to poke holes in this scheme if you see an opening. It would also be nice, because you could assign high M to popular/controversial artilces and save some bandwidth.--Joel 20:19, 3 October 2005 (UTC)
You should check out Freenet. Running a Wiki on it maybe possible... Haon 11:46, 5 October 2005 (UTC)

Global warming[edit]

What is global warming?

Please see Global warming. -- Rick Block (talk) 00:20, 30 September 2005 (UTC)
Tis just a wacky liberal conspiracy theory, like evolution and gravity....!

what is carbon dating[edit]

Not my sister, I can tell you that much! Seriously, though, see Carbon dating. -- SCZenz 00:37, 30 September 2005 (UTC)

Is that the kind of snarky comment you wanted to put in a template? :) DirkvdM 18:05, 30 September 2005 (UTC)
Nah, that's the kind of snarky comment that proves we shouldn't have a template. It only works with carbon dating...! ;) -- SCZenz 20:18, 30 September 2005 (UTC)
In reference to this specific snarky comment, one would hope that whomever your sister is dating, that they contain substantial amounts of carbon :) --Robert Merkel 04:29, 3 October 2005 (UTC)
Which leads us to the unavoidable question if aliens would necessarily have to be carbon based. Which is a totally philosophical question which is not meant to suggest anything about SCZenz's sister :) . DirkvdM 18:45, 3 October 2005 (UTC)

History of Prednisone[edit]

Who discovered Prednisone and which drug company owned the rights before it became a generic drug?

Your link says the company was Schering. alteripse 01:55, 30 September 2005 (UTC)

what is the name for water tension[edit]

The surface tension of water, probably. AySz88^-^ 02:42, 30 September 2005 (UTC)

See also meniscus --PopUpPirate 13:07, 4 October 2005 (UTC)

What is circular DNA?[edit]

Can anyone tell me what circular DNA actually is? What is its difference with double helix DNA? Does it duplicate in the same way as double helix? Where can it be found? [this is not a homework question! It's just that I can't find anything about this in my books and google didn't help much] Thanks in advance.

Circular DNA is just what it sounds like: a strand of DNA that is formed into a loop. It replicates like all other DNA, it just doesn't have loose ends. It can be double-stranded or single-stranded. Some places you'll find it: plasmids, bacteria, and mitochondria. - Nunh-huh 03:04, 30 September 2005 (UTC)

In most cases, it's double-stranded, and in those cases, it's not different from a double helix; it still has a double-helical structure. The scale at which the double helix appears is much smaller than the scale of the circle formed by the DNA. Imagine if you took a telephone cord (the coiled kind used to connect the handset to the base on corded phones), unplugged both ends, then plugged both ends into one of those connectors usually used to connect two cords. The cord would now be circular on a large scale, but still coiled--helical--on a smaller scale. Similarly, double-stranded circular DNA is still a double helix on a small scale, and circular on a larger scale. Chuck 16:56, 30 September 2005 (UTC)
Also most bacteria have an enzyme complex that methylates their own DNA as a way of distignuishing it from invading viral DNA, it's essentially a way of adding specificity to certian bacterial lysases, so they don't cleave their own genetic material by accident.. I'm not sure but I imagine it would be hard to methylate helical DNA, but I don't know if the methylation would nesseserily change the conformation, of it it just takes advantage of the conformation change--172.208.123.70 14:16, 2 October 2005 (UTC)

Ignition point of wood in the absence of flame?[edit]

I am trying to find out at what temperature will wood ignite in the absence of an open flame? 150 degrees? 160 degrees? Peace. Denis.

  • I couldn't tell you for sure, but I'm confident it depends on exactly what kind of wood we're talking about. Redwood? Oak? Maple? Mesquite? - Cobra Ky Flag of the United States.svg (talk, contribs) 04:00, 30 September 2005 (UTC)
I believe at least book paper spontaneously ignites at Farenheit 451 (233 Celsius), hence, the name of the book. I would expect most woods would require a higher temperature. -- Rick Block (talk) 04:16, 30 September 2005 (UTC)

Respirable Liquid[edit]

Hi. I saw in a movie AND in a misc documentary a "respirable liquid" where animals (including us) can breath with some resistence because the liquid is more dense than the air. Can someone please help me to find out what kind of liquid it is and his formulae? Thank you all in advance. Baruch.

Please see liquid breathing. -- Rick Block (talk) 06:22, 30 September 2005 (UTC)

Information system management[edit]

What is meant by metadata? What is meant by intranet and extranet? What is meant by an automated system?--Andeep 06:21, 30 September 2005 (UTC)Andeep

Why a pair of bones?[edit]

Human beings (and possibly all vertebrates) have two bones parallelly placed in their limbs: Radius and Ulna in the arms and Fibula and Tibia in the legs. But why two bones instead of one? I mean why did the humans body evolve in such a way as to have a pair of bones? What advantage does having two bones have over one single bone that is strong enough ?

Impact and forces are spread over a larger area, without the additional weight that one big bone would add. Additionally, if one bone is broken, then the other will provide some kind of support whilst it heals. This is not important now, but a long time ago, in early land based animals, this may have been a difference between that creature surviving or dying (and this makes a big difference over a few million years of evolution) Proto t c 10:07, 30 September 2005 (UTC)

In additions to the excellent reasons given above, two bones work better than since our joints do not freely rotate in all directions. Think about pronating and supinating your hand when your elbow is held still at 90 degrees. Try to imagine a one bone system that would allow that. You will get the idea. Finally, historical contingency: i.e., many biological mechanisms are not the most efficient imaginable but show traces of gradual imporovement over earlier versions that originally served for other functions. alteripse 10:26, 30 September 2005 (UTC)

The responses above explain the uses to which these bones have been put by modern animals, but of course the real reason why we have two bones in this position is that our ancestors had them, and they had them because their ancestor had them, and so on back to the osteolepiformscrossopterygian ancestors of the tetrapods — which had a radius and ulna articulating with their pectoral fin, and a tibia and fibula articulating with their pelvic fin. (Eusthenopteron is a typical osteolepiform from the late Devonian).
There's a detailed description of the anatomy of Eusthenopteron at [11]. See also "The evolution of tetrapod limbs: How did fishes obtain their limbs?" by Keiko Shimizu-Nishikawa (a missing "next" link after page 6 means you need this link to read the rest). Gdr 20:08, 7 October 2005 (UTC)

staggered vs eclipsed conformations[edit]

hi, mu question is what kind of steric energies contribute to the energies of staggered conformations, and which ones contribute for the energy of eclipsed conformations in the case of ethane. thank you

cabi.

  • hum, let me think, DO YOUR OWN HOMEWORK, and also, try a little harder to rephrase the question so it doesn't sond like it's right out of a text book, they do have a verbal section on the MCAT you know?--172.208.123.70 14:10, 2 October 2005 (UTC)

sex toy[edit]

I have a problem in my penis physic and I wanted to know if there is a artificial penis which could be able to inject my cum to my wife's reproduction system or not .

Artificial insemination is indeed possible, but it's not performed with toys. In vitro fertilisation may be another option if you wish to have a child but are not physically able. The best way to start would be to simply get in touch with your doctor. Of course, the Wikipedia:Medical disclaimer applies. Garrett Albright 09:46, 30 September 2005 (UTC)

Right, not toys but kitchen utensils, like a basting syringe. NOTE: I am not recommending you try this and can think of a few potential risks. alteripse 10:21, 30 September 2005 (UTC)

Actually, I remember reading about a strap-on dildo that served this purpose. AFAIR, it was used by women when they wanted to simulate a male ejaculation, but you could obviously use it in this case by using real semen instead of fake. ? Kieff | Talk 10:33, 30 September 2005 (UTC)

Need a documentation tool for C[edit]

I have many C files with Javadoc-style comments. Each statement contains a comment before it. I need to generate documentation from this. I am looking for a tool which takes the C files and generates a file from which the documentation and the corresponding source code can be easily extracted (ie, more easily than by parsing the source code). I tried Ccdoc but it processes only header files. I tried Doxygen but it loses the correspondence between the comments and source code. —Masatran 12:44, 30 September 2005 (UTC)

You can set Doxygen so that it creates HTML files that are visually identical to your source code, except with code colouring, and hyperlinks everywhere so that you can follow relationships -- this output seems to be much closer to what you describe than the default doxygen output. Haven't got a copy handy to tell you what the option's called, I'm afraid. Ojw 21:13, 30 September 2005 (UTC)
Something like Perl is Your Friend; if I understand your problem correctly, languages such as Perl are designed for particularly this problem. It's not really harder than "parsing the source code", though. Dysprosia 22:20, 3 October 2005 (UTC)

Unique Human bodypart?[edit]

Hi, is there a body part unique to humans? e.g. eyebrows. Thanks - Ieuan Willox

I can't think of an obvious one. However, teeth are often unique to a given species - one of the points of contention over homo florensis involves the numbers of roots on a molar, or something - so you could possibly argue that our teeth are, in fine detail, unique to humans. Other than that, I suspect most things are shared with some form of ape. Shimgray | talk | 13:10, 30 September 2005 (UTC)
The obvious one is People have a much larger brain than any other creature.
Not at all, a wale brain weighs nearly 8kg (next to our puny 1.5kgs), see Whale for more information. --fvw* 13:29, 30 September 2005 (UTC)
Didn't know that, that is why I go to Wiki
Actually, contrary to popular belief, whale brains are pretty unimpressive for their body size, and don't really imply great intelligence (some dolphins, though, do have rather large brains for their body size).--Pharos 15:38, 30 September 2005 (UTC)
Of course the human brain doesn't nesseserily imply intelligence either (;--172.208.123.70 14:05, 2 October 2005 (UTC)
Eyebrows look unique, but most other creatures are so furry the eyebrow is just part of the fur
I don't think there's any, because we didn't evolved all that as a species except for parts of the brain. ? Kieff | Talk 14:47, 30 September 2005 (UTC)
I suppose your phrase was supposed to be "we didn't evolve all that recently as a species". Good point, because we are rather lonely as a species; there's just one race (contrary to popular belief) and our closest relatives aren't all that close (apparently somewhere in our evolutionary history we made a very 'close escape' somewhere). So it's only because we're so young that we haven't evolved further away from other animals. But what parts of the brain are you talking about? I thought that it was just the size (relative to our bodies) that makes our brain unique. DirkvdM 18:29, 30 September 2005 (UTC)
Thanks for correcting. And in respect to that part of the brain, see neopallium and hippocampus for instance. ? Kieff | Talk 07:32, 1 October 2005 (UTC)
The hippocampus is one of the oldest parts of the brain (according to the article), so that is nowhere near unique to humans. Your neopallium caught me off guard, but that turns out to be simply the neocortex, which is something at least all mammals have (I believe). It is indeed what sets us most apart from other animals, but, again, only because of its size. DirkvdM 18:34, 3 October 2005 (UTC)
A philosopher might say that "consciousness" could count as a body part, but the cognitive scientist would ponder what that would mean and whether or not we know enough to exclude chimps and dolphins from this category. The historian would note that this debate goes back hundreds of years, even before the theory of evolution was accepted in any form. --Fastfission 15:31, 30 September 2005 (UTC)
Here's a philosopher who certainly wouldn't utter such nonsense! :) DirkvdM 18:29, 30 September 2005 (UTC)

Oh, so there's no unique body part, I was sure I'd read somewhere that there was but I must be wrong. I need this information for something I'm writing,and it wouldn't really need to be unique, I suppose, just unique of animals native to Britain? I know I'm asking a lot but I hope you can help.

Do our close primate relatives have Appendixes? User:Zoe|(talk) 06:09, 1 October 2005 (UTC)

Do they have a belly button? (and did Adam?) Ojw 18:16, 1 October 2005 (UTC)
Now that you bring that up. Why are umbellical cords clipped and turned into bellybuttons? Is there a risk of infection? DirkvdM 18:34, 3 October 2005 (UTC)
Here's the first result for Googling 'appendix primate'. Apparently the discussion is still open on this. And I'd say it's a good candidate, since it's something that (as far as we know) has no function. And since it can get infected and is therefore a hazard one would expect it to evolve away. If other primates have it then it evolved before primates evolved and hasn't disappeared since. Which sounds unlikely. I've always thought this whole idea that there would have to be one thing that is unique to humans was bullshit (it's the totality of what we are that makes us and any other animal unique), but I hadn't thought of this yet. Good one! DirkvdM 18:34, 3 October 2005 (UTC)

Speed of light - where's the energy?[edit]

If the speed of light slows down when a photon (or em wave) meets an air-glass boundary, then what source of energy accelerates the light photon (or em wave) back to air-speed when it traverses the glass-air boundary?

It turns out that the photon loses no energy when it enters glass, even though it slows down, and therefore needs no extra energy to speed back up later. For the energy of photons we generally write E = h \nu, and the frequency ν doesn't change when the photon enters a medium.
I can't come up for a great explaination of why the energy doesn't change, but I can think of an experiment that might make you think it's plausible: tie together three sections of string such that the middle section is a thicker, heavier variety than the first and third sections, tie the end of your Franken-string to the wall, and start moving the other end up and down to make waves. You should see that the waves slow down in the middle bit, but no one is there at the string junction slowing down and then speeding up the waves.
There's no one taking energy out at the first knot and putting it back in at the second knot, so the wave must have the same energy when it's faster in the lighter string as when slower in the heavier string. Hope that helps. — Laura Scudder | Talk 14:16, 30 September 2005 (UTC)
There's an important distinction between the 'speed of light' and the speed of the photons that make up that light. Our article on speed of light has a good explanation of this phenomenon. Essentially, photons travel a the full (vacuum) speed of light at all times. When they travel through a medium (like glass) they repeatedly run into and interact with particles (atoms and molecules in the medium)—the photons are absorbed and then reemitted. These interactions take a small but appreciable amount of time, reducing the apparent average velocity of the light through the medium.
Since the probability of these interactions varies with the wavelength (energy) of the photons, the speed of light in a medium is dependent on wavelength. This is how prisms are able to split light into a spectrum. TenOfAllTrades(talk) 14:26, 30 September 2005 (UTC)
Of course, you can have a fairly self-consistent understanding of light as waves, as long as you stick to the medium. The experiment above with strings of different weights also works in water of various depths. EM waves slow down in a medium because some energy goes into polarizing the medium, e.g. a slight shift in the electron cloud of the molecules the wave passes through. All three of these illustrate a very general concept called impedance, which has to do with the difficulty of creating the displacement/polarization that makes up the wave.
It's interesting to note that this slowing effect happens even when absorption and emission of a particular wavelength are forbidden by quantum mechanics, and so cannot be explained fully by Ten's analogy. But, as in his model, almost all of the energy of polarization is passed along to the next section of medium as the wave travels. The real brain teaser is, where is the energy stored as the photon travels through vacuum? If there's no medium to polarize, what holds the electric field? The short answer is, the photon speeds up so much that, according to special relativity, the media on either side of the vacuum appear to be touching one another from its perspective. Due to length contraction, it doesn't notice any gap at all, even a gap lightyears wide; due to time dilation, the energy is stored for exactly 0 time, therefore no medium is needed to store it.--Joel 19:31, 30 September 2005 (UTC)
A note about 'forbidden' transitions in quantum mechanics. You can actually get away with a great deal if you do it very quickly—very short-lived states have a very broad associated energy uncertainty. Joel's description fits best if you want to deal with photons as waves; the absorption/emission model works best if you want to deal with photons as particles. TenOfAllTrades(talk) 21:01, 30 September 2005 (UTC)

Educational technology companies in Boston[edit]

Are there any companies or projects working in educational/instrunctional technologies in Boston?

Thanks for any help!

Mary

Yes, almost certainly. Surely a Boston Yellow pages would be more useful than wikipedia in locating them. Ojw 18:11, 1 October 2005 (UTC)

CHANGES IN CHEST&LUNG VOLUME[edit]

WHEN PERFORMING THE HEIMLICH MANEUVER, HOW DOES THIS ACTION CHANGE THE VOLUME OF THE CHEST AND LUNGS? WHY DOES IT CAUSE THE FOOD TO BE FORCED FROM THE AIRWAY? WHOSE LAW EXPLAINS THIS?

THANKS
Have you read the Wikipedia article: Heimlich maneuver? --hydnjo talk 17:07, 30 September 2005 (UTC)
AND NEXT TIME COULD YOU REFRAIN FROM SHOUTING PLEASE? 

Thank you. DirkvdM 18:47, 30 September 2005 (UTC)

It sounds like your teacher wants you to say "The Heimlich maneuver decreases the volume of the lungs" and "Boyle's Law explains this". You should read the latter article to find out why... - Nunh-huh 03:06, 1 October 2005 (UTC) (People don't breathe ideal gases, but it's close enough for government work<g>).

Penis Roll[edit]

On last week's episode of "Going Tribal" on the Discovery Channel, the host has his penis "rolled" by natives and it "jumped back into his body". Exactly what does this mean, what occurs, and how did this come to be considered a good idea? Also, does it work in reverse?

It sounds like a sort of reverse hernia. Some guys have un-descended testicles, perhaps it's similar to that. I don't know about the anthropology of it, but I'd guess that it started with someone playing with himself (by which I do not mean masturbation) and at some point acquired a cultural significance. Superficially, it doesn't sound like as bad an idea as piercing one's ears. It might jog someone's memory if you could remember what place these folks were native to...--Joel 21:22, 3 October 2005 (UTC)

Oysters and spirits fact or fiction[edit]

I've heard that mixing raw oysters and spirits ("hard liquor") can cause "harmful effects". Exactly what are the effects, and WHY? Or is this just a myth?

Well there is a connection in that some folks thought that the alcohol would kill any "bad" contaminants. It didn't and so started the urban legend. But on a more sober note, this FDA publication documents some potentially severe interactions. --hydnjo talk 19:22, 30 September 2005 (UTC)
That's not really an interaction. Alcoholism can cause liver disease, and liver disease increases susceptibility to Vibrio vulnificus, and oysters can be a source of Vibrio, but having a drink with your oyster causes no problems per se. - Nunh-huh 22:17, 30 September 2005 (UTC)
Correct, I did muddle interaction and susceptibility. The "urban legend" that I was referring to was the belief that if the oysters were of dubious origin then dunkin' them in spirits would rid it of Vibrio (which it didn't) and so when the ill effects occured the eater (rather than blame his poor judgement) would blame the oyster/alcohol combination to save face. --hydnjo talk 23:49, 30 September 2005 (UTC)
Supposedly oysters increase libido and liquor reduces inhibitions, it is not hard to imagine this can result in unexpected parents.
If the two of you have decided you'll sup on oysters and spirits in the first place, I suspect you're half-way there anyway.... - Nunh-huh 22:17, 30 September 2005 (UTC)
... how could you tell? Cheers, --hydnjo talk 23:27, 30 September 2005 (UTC)
Myth or not, I have eaten oysters at several restaurants which had specific cautions on the menu to avoid (much) consumption of spirits with oysters. No reasons were given. Notinasnaid 22:51, 1 October 2005 (UTC)
Urban legends do have a way of infiltrating our culture. Hey, if it's on the menu (or on the television set) it must be true. --hydnjo talk 06:09, 3 October 2005 (UTC)

tickling[edit]

Why can you not tickle yourself but shy away when someone tickles you.

Read the Wikipedia article Tickling and the Research section there has an explanation. --hydnjo talk 19:06, 30 September 2005 (UTC)
Apparently, you can tickle yourself, if there's a delay (or other signal-processing step) between your actions and your perception of their effects. I think the experiment involved a motor pushing against your hand -- if someone else controlled it, it tickled. If you controlled it, it didn't tickle. If there was a delay (i.e. no obvious correlation between your movements and the sensation) then it tickled more the longer the delay was. Ojw 18:10, 1 October 2005 (UTC)

Ozone Layer[edit]

What fraction of incoming solar UV light does the ozone layer absorb?

If you read the Ozone layer article you will get a better appreciation of what is going on. You'll also find the answer to your question there. --hydnjo talk 19:38, 30 September 2005 (UTC)

Software Chronic Crisis[edit]

can anyone explain or send me a link of a summary of Software's Chronic Crisis TRENDS IN COMPUTING by W. Wayt Gibbs, ???

    • Is this what you are looking for? --hydnjo talk 20:40, 30 September 2005 (UTC)

Mysterious Smokey Lines Around Nuclear Explosions[edit]

In many photographs of nuclear explosions I often see smokey lines off to the sides (see [12] for an example). What causes these lines and why do they happen? I've heard of the rope trick effect but these aren't cause by guy lines, and they re visible for some time after the initial fireball.

  • I believe that these are deliberately set markers, so that the effects of the shockwave on the surrounding air can be seen. See [13] for more. -- Bob Mellish 22:12, 30 September 2005 (UTC)
Thanks! I never imagined they were from smoke rockets. I always thought they were some product of the explosion themselves. --138.162.140.37 22:35, 30 September 2005 (UTC)

Butyric acid and odour of socks and blue cheese[edit]

Recently in my chemistry class we synthesised esthers using alcohols and carboxyilic acids. One such acid was butyric acid, a smell with a characterstically bad smell.

  • I'm going to assume you mean esters, since esther isn't a word--172.208.123.70 14:03, 2 October 2005 (UTC)

My science teacher said that it was this acid that caused the smell of blue cheese and of smelly feet, but neither the wikipedia entry nor a web search seemed to agree with him. Is butyric acid responsible for these smells, and if not, what chemicals are?

  • Our article on Butyric acid says it can be found in rancid butter, parmesan cheese and vomit. I don't know whether it can be secreted by smelly feet, but I live for the person with those feet if that's the case. - Mgm|(talk) 22:29, 30 September 2005 (UTC)
Some things are agreed on: butyric acid has a very unpleasant odor, and it is butyric acid that gives rancid butter or spoiled meat their noxious aromas. Butyric acid is also found in sweat. I suspect that the smells of "smelly feet" and of blue cheese are rather complex affairs, and that the scent of butyric acid is a component of both smells, but that opinions may differ as to which scents predominate in these complex aromas (indeed, I rather suspect that the "mix" varies from foot to foot and cheese to cheese.... - Nunh-huh 22:29, 30 September 2005 (UTC)
It is plausible. Butyric acid is usually formed by the bacterial metabolism of fats, and sweat contains some fat. Physchim62 10:18, 2 October 2005 (UTC)

How does the Internet work?[edit]

We have a nice article on the Internet and HowStuffWorks also has a nice article on the infrastructure of the internet (click here) which happens to be the second result if I type the question you asked into Google (click and see). Please consider using a search engine to find your answer first. - Mgm|(talk) 22:33, 30 September 2005 (UTC)

Heart[edit]

What causes blood to enter the right atrium of the heart?

You really should read the Heart and Atrium (anatomy) articles. They will will most likely answer your question. If you still have some confusion after reading the articles then come on back and we'll try to clear things up. --hydnjo talk 00:14, 1 October 2005 (UTC)
I don't think those articles actually do help much - nothing there that I can see on venous physiology. Blood is returned to the heart mostly via the deep venous circulation. These deep veins are enclosed inside contracting muscles, and contain valves that prevent backflow). Sixty percent of the blood present in the calf veins is expelled into the popliteal vein (below the knee) with a single, normal calf muscle contraction. [14]. The deep venous circulation goes into the inferior vena cava (from the legs) or superior vena cava (from above) and thence into the right atrium (from whence our articles have it covered). - Nunh-huh 02:52, 1 October 2005 (UTC)
In reading those articles I concluded that the return flow to the right atrium was a result of the pressure caused by ventricular pumping action that is, pumping blood by the action of the right ventricle into the pulmonary artery and then when it returns from the lungs through the pulmonary veins it goes into the left atrium. Then after going through the mitral valve, the blood is again pumped by the left ventricle this time through the aorta. This final pumping action results in pressuring blood flow throughout the body and returning it through the superior and inferior vena cavae into the right right atrium and through the tricuspid valve into the right ventricle and so on. This is what causes blood to flow (enter) the right atrium. That was my understanding after reading our articles. --hydnjo talk 04:56, 1 October 2005 (UTC) Strike my flawed response. --hydnjo talk 18:32, 1 October 2005 (UTC)
Then our articles are defective! The left ventricle doesn't supply the force that returns the blood to the heart. See [15], [16]. Mean circulatory pressure has no physical meaning as a driving pressure behind venous return. Normal Central Venous Pressure (though it can't be said to control venous return) is only about 2-6 mmHg. - Nunh-huh 07:23, 1 October 2005 (UTC)
I think the heart sucks, like this. I've seen toys that have liquid in a closed path, a one way valve and a rubber bulb. The valve keeps the flow in one direction and the bulb sucks the liquid in from the return path, even if there is no pressure on the return side. --JWSchmidt 20:04, 7 October 2005 (UTC)

Electron migration speed[edit]

When I close a switch to a circuit, someone down the line will be aware of that action at (nearly) the Speed of light. My question is, what is the speed of the individual electrons or what is the speed of electron migration as opposed to the signal speed? I hope I said it right, --hydnjo talk 01:27, 1 October 2005 (UTC)

You ask good questions<g>. This is a very complicated subject. See if this page is helpful. - Nunh-huh 02:55, 1 October 2005 (UTC)
This page (thanks Nunh-huh) is exactly what I was looking for. And also this (thanks SCZenz). My comments in the following paragraph have to do with something entirely different, I confused myself again. --hydnjo talk 19:52, 1 October 2005 (UTC)
I was inspired to ask this question from the query above: "Speed of light - where's the energy?" I think I found the answer at Current (electricity) which states that (electron migration speed) "in the near-vacuum inside a cathode ray tube, the electrons travel in near-straight lines ("ballistically") at about a tenth of the speed of light." The link above "(this page)" was also helpful but I was wondering about the speed of electron flow as a fraction of the Speed of light. That's what I was curious about. --hydnjo talk 04:05, 1 October 2005 (UTC)
Actually, I believe that in wires individual electrons are moving extremely slowly (a few cm per hour), and that the electrical signal, while much faster, still travels much slower than the speed of light. See here. -- SCZenz 06:01, 1 October 2005 (UTC)
My chemistry teacher used to quote 1mm per second, but I don't know his source for that number. Ojw 18:04, 1 October 2005 (UTC)
 \sigma = q n \mu_n
where n is electron density (number of electrons per cubic centimeter), q is electron charge (Coulombs per electron), and μn is electron mobility. Electron mobility is given by
 \mu_n = -{\langle v_x \rangle \over \mathcal{E}_x }
where \mathcal{E}_x is electric field in the x-direction in Volts per centimeter. Given a copper wire with a length of one meter, a diameter of one millimeter, and a potential difference of one Volt across it, then its electrons will drift at about 4.3 millimeters per second. The calculations are shown at the webpage hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html#c2, which also offers good explanation. This kind of question probably falls into the category of solid-state physics. —AugPi 20:44, 7 October 2005 (UTC)
  • Putting the above two equations together results in
 \langle v_x\rangle = {-\sigma \mathcal{E}_x \over q n}.
Copper's conductivity is 5.88x107 per Ohm-meter [17]. Potential difference in the given problem was stated to be 1 Volt per meter. Electron charge is 1.602x10−19 Coulombs. Copper's (free?) electron density is 8.47x1028 per cubic meter [18]. Putting it all together:
 \langle v_x\rangle = {-5.88 \times 10^7 \left[{1\over \Omega m}\right] \cdot 1 \left[{V \over m}\right] \over 1.602 \times 10^{-19} [C] \cdot 8.47 \times 10^{28} \left[{1\over m^3}\right]}
=0.004333 {\left[{A J \over V m C m}\right]   \over \left[{C \over m^3}\right] } 
 = 0.004333 {\left[{C C J \over s J m C m}\right] \over \left[{C \over m^3  } \right]}
 = 0.004333 {\left[{C \over s m^2}\right] \over \left[{C \over m^3  }\right]  }
 = 0.004333 \left[ {m \over s} \right],
since Ohm = Volt per Amp, Volt = Joule per Coulomb, Amp = Coulomb per second, the Joules cancel out, the Coulombs cancel out, squared meters cancel out, leaving meters per second. (The minus sign is here irrelevant.) So the answer is 4.333 millimeters per second, as stated. —AugPi 22:33, 7 October 2005 (UTC)

Capillary action and glass a couple small questions.[edit]

Hello. And thank you for your time first of all. Ill just cut to the bone.

I have found capillary tubes on the internet at .4 -.6 mm ID. What i would like to do is bend it about 120 deg. Actually i would like to bend sevral tubes together. The thing is im not to good at working with glass. If i were to heat the glass to the point i could bend it i fear i would collaps the id or at the least distort it to the point it would no longer work. With a copper pipe you can simply place a spring slightly larger than the OD of the pipe so as to hold its "roundness" as you make your bend. But with glass and being so thin to begin with i think i would have problems getting and keeping the glass hot enough withought being to hot to get a good bend. If possable i would like to bend say 20 tubes together and hopefully end up with extra capallary paths by default in the space between the tubes. But i also think bending more than one at a time would stretch the outer tubes or crimp the inner ones. And heating all evenly could be tricky.

My question is: How could i bend capillary glass and not destroy the id. And if possable how could i bend more than one at a time so as the bend is matched? How shallow of a bend would i need? And how could i bend more than one so that they could be stacked together close enough. Preferably a way i could do this in my garage without spending a ton of money. : )


Also all the searches i find on capillary action use water. I have read that water and glass is one of the best ways to observe capaillary action as they work great together. But i cant seem to find to much information on other liquids capillary properties. For example does mercury work well in a capaillary sence and what material tube would work well for that. It seems to have good surface tenssion. --68.42.226.224 01:41, 1 October 2005 (UTC)

Heated mercury can get into your bloodstream. It is a poison. The capillary action article indicates you are probably better off choosing another liquid besides mercury, as it would work in reverse. Ancheta Wis 11:56, 1 October 2005 (UTC)

what is a medicinal plant starting with ne[edit]

Well here is a start: Ne and then on to Nee and then finally to Nel. I hope it's in there somewhere. --hydnjo talk 04:18, 1 October 2005 (UTC)
Neem is a medicinal tree. --nixie 10:40, 1 October 2005 (UTC)
Category:Herbal & fungal drugs/medicines suggests Nettle. Thryduulf 10:51, 1 October 2005 (UTC)

Time problem[edit]

I'm taking the PSAT/NMSQT in a few days, so I need some help. How do you solve the problems that go something like "The clock above shows a time of 5:00. If the clock keeps accurate time, what time will it show exactly 125 hours later? --Neutralitytalk 04:30, 1 October 2005 (UTC)

This is a modular arithmetic problem. If it's 5:00 now, how many hours until the clock shows 05:00 the next time? Ans=24, or perhaps 12 depending on whether we're talking about a 12 or 24 hour clock. So the key is to realize every 24 (or 12) hours gets back to 05:00, so it's 05:00 24 hours later, and 48 hours later, and 72 hours later. The "in between" numbers are just like adding 1-23 hours to 05:00 but starting with a base that's the nearest multiple of 24 (or 12). What this is, is the remainder after dividing the total number of hours by 24 (or 12). 125 hours later is just like 5 hours later (remainder when dividing 125 by 12 or 24 is 5), so the clock says 10:00. -- Rick Block (talk) 04:43, 1 October 2005 (UTC)
125 = 12 * 10 + 5 (=24 * 5 + 5), so the clock will be 5 hours' ahead of its starting position, i.e. 10:00. You just have to look for convenient multiples of 24.
More generally, there's a lot like this in student math competitions, which sounds a bit like what you're doing. For example, the famous 17.5% VAT problem (take 10% by moving the decimal place, halve it to get 5%, halve that to get 2.5%, and add those 3 numbers to get 17.5%) -- it definitely pays to be sneaky and look for the shortcuts. Ojw 17:53, 1 October 2005 (UTC)

In addition, how does one solve problems like this quickly:

How many three-digit numbers greater than 240 can be formed by using three different digits from the set of {1, 2, 3, 4}?

--Neutralitytalk 04:39, 1 October 2005 (UTC)

For numbers greater than 300, you have the possibilities of '3' or '4' followed by any of the remaining digits, following by one of the remaining digits again. This is 2 ('3' or '4') x 3 x 2 = 12 possibilities. For the numbers between 240 and 300, you must select '2' as the first digit, then '4' as the next digit, and then there are two possibilites for the third, so you have an additional 1 x 1 x 2 = 2 results. Total result = 12 + 2 = 14. Most such problems are just a matter of multiplying out the possibilities, but in this case the constraints meant we had to break it into two problems.-gadfium 04:55, 1 October 2005 (UTC)
In general, the number of ways to order (permututate) X different objects is is X! (the factorial of X, i.e 1*2*3*4*...*X). For instance you can order A,B,C in 3!=1*2*3=6 ways(ABC, ACB, BAC, BCA, CAB and CBA). This is because you can select the first thing in 3 ways, the second in 2 ways, and the third in only 1 way, ie. 3*2*1=6 ways total. Hope this helps gkhan 11:32, 1 October 2005 (UTC)
You can start with 2 numbers (3,4). Then you have a choice of 3. Then you have a choice of 2. 2*3*2 = 12. Then notice a couple of possibilities you've missed (241,243). Total 14.
More generally, consider how much time pressure there is. If you can count the results quicker than doing a formula, write down the answer and move on -- multiple-choice tests don't give you any marks for an elegant solution applying formulas from permutation theory, but they often do reward people who can solve 200 questions per hour with reasonable accuracy. Ojw 18:02, 1 October 2005 (UTC)

statistics[edit]

What are the limitations of Statistics?

As in what? Prediction? ? Kieff | Talk 10:56, 1 October 2005 (UTC)
If you have a mathematical viewpoint, Statistics all looks like guessing and you can never be sure that you can depend on what you are looking at. (Statistics was first developed for Kings so that they could tax their realms more efficiently. Thus they didn't have to worry about exact answers.) But statisticians can give you the amount by which your guesses are likely to be wrong. Ancheta Wis 11:47, 1 October 2005 (UTC)

statistics is only as accurate as the data set that the statistis are based on. Also, they are subject to systematic bias, however there are tests for such bias, but correcting it usually involves adding another counteracting bias. However, if one knew the true values, then there would obviously be no need to do statistics. -Drdisque 20:48, 1 October 2005 (UTC)

I can't tell you with complete certainty. Ha ha, just a joke. Seriously, I was taught in High School the smallest usable data set is 10, below that you can't reliably get means or standard deviations from the data. JamesHoadley 15:34, 8 October 2005 (UTC)
I put the minumum useful sample more around 1100, which will provide a 3% margin of error over a 50% confidence interval. Less accuracy than that, say for a pre-election poll, would likely mean the poll's margin of error would be larger than any actual differece in the candidates' numbers. StuRat 08:04, 9 October 2005 (UTC)

Limit Definition of a Derivative[edit]

Find the slope of y=x+1/x at (5,26/25) using the limit definition of a derivative. (I can use the differentiation formulas, but the limit is what troubles me here.)

m=\lim_{x \to 5}\frac{x+\frac{1}{x}-\frac{26}{25}}{x-5}.

This reduces to m=\lim_{x \to 5}\frac{25x^2-26x+25}{25x \times (x-5)}. As you see, the numerator of the second limit is prime; I can't evaluate the limit because of the (x-5) in the denominator.

Please help me.

--Henry


m=\lim_{x \to 5}\frac{x+\frac{1}{x}-5-\frac{1}{5}}{x-5}.\ 

\mathrm{Next}, m=\lim_{x \to 5}\frac{(x-5)+({1 \over x}-{1 \over 5})}{x-5}.


Now cancel the (x-5)s out of every term in the expression on the right.

Therefore,\lim_{x \to 5}(1-{1 \over 5x})=1-{1 \over 25}={24 \over 25}.

--Henry

(added after edit conflict)
First off, it's not 26/25, it's 24/25 :P
It was a coupl of years since I done this, but oh well :P. You're limit definitition is all wrong. The definition of a derivative of a function f(x) is
f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}
which becomes
f'(5) = \lim_{h \to 0} \frac{5+h + \frac{1}{5+h} - (5 + \frac{1}{5})}{h}
which simplifies to
f'(5) = \lim_{h \to 0} \frac{24 - 5h}{25 - 5h}
Cheers gkhan 07:43, 1 October 2005 (UTC)
There are two definitions of the derivative. You've each written one of them. -- SCZenz 19:25, 2 October 2005 (UTC)

Wha? Look, last time I checked this was still the ENGLISH Wikipedia! Take your strange language to http://math.wikipedia.org/wiki/ --inks 10:36, 1 October 2005 (UTC)

d00d! y00 suxz! m4th is teh l337 :D gkhan 11:20, 1 October 2005 (UTC)

TV on the computer monitor[edit]

I am wondering if such equipment exists that'll put (cable) Television onto my desktop computer monitor. I am not talking about streamed TV over the internet, I want to somehow plug my monitor and speekers into the TV cable line. To do this I would need a cablebox (to change channels), are there any that can connect to my Monitor?

I apologize if my question is badly written, I am tired. -anon

You can't do it without a peripheral card in your PC that accepts your television standard. Right now the TVs that can also serve as computer monitors cost more than bottom of the line PCs. You won't save any money at the moment. This is not an accident. Ancheta Wis 11:38, 1 October 2005 (UTC)
If you already have a video card that will accept Video/Sound Out (or even SCART) somehow, it would just be a matter of connecting it to the right outputs on the cablebox. Have I missed something here?--inks 23:48, 1 October 2005 (UTC)
There is something called an LCD TV which will accept TV connections. If your video card has RCA/S-video in then you can get limited TV support. Your best bet is getting a TV tuner card, they can usually found for about 30-40$

Normalization of scale[edit]

How normailzation of scale is done before performing data anlysis.

First find the largest number in the data set. Then divide your results by that number. Be sure to state that number in your displays. Ancheta Wis 11:34, 1 October 2005 (UTC)

Normalization of scale[edit]

Is it necessary to perform normalization of data before data analysis.If so how normailzation of scale is done before performing data anlysis.

sandeep

This depends on what sort of data you are working with, and what sort of information you wish to extract from it. What sort of data are you working with? You might, say, use the standard deviation of the data set as a relative measure if it is finite. You might also want to read nondimensionalization too. --HappyCamper 20:04, 1 October 2005 (UTC)

planets[edit]

Planets? ? Kieff | Talk 16:40, 1 October 2005 (UTC)

what is dsl?[edit]

I suppose you mean Digital Subscriber Line? ? Kieff | Talk 16:40, 1 October 2005 (UTC)


DSL can also mean Damn Small Linux. There is a good article on DSL though.

Aluminum can alloy[edit]

It says in the magnesium article that it is a component in aluminum soda cans. I can't seem to find any other sources that agree with that. Can anyone verify/disprove that?

what is epidemiology[edit]

see epidemiology. Thryduulf 17:27, 1 October 2005 (UTC)

Periodic Table[edit]

What is an element that I can see as a soild, liquid, and gas?

Since all solids and liquids distort light enough for you to "see" that something is there, any element that is colored as a gas would fit your criteria. Chlorine is an example but I am sure there are others. alteripse 20:58, 1 October 2005 (UTC)

what is an catalytic antibody[edit]

It's an antibody with catalytic properties, duh... pay attention during your lectures... you specifiy an antibody to mirror the properties of a biological molecule with catalytic activity, usually some sort of enzyme... then you have an analog of an enzyme reactive site that you can target to specific tissue types... try here Catalytic Antibody if it exists--172.208.123.70 13:52, 2 October 2005 (UTC)

Off-Label Use; FDA Application for[edit]

Am advised that before a clinical study utilizing an 'already approved' medication (to kill a newly discovered microorganism) will be 'monitored' by a medical Institutional Review Board (IRB) - an application for its (the medication's) "Off-Label Use" must have been submitted to the FDA.

A means of potentially eliminating the No. 2 killer, heart disease, (including stroke, TIAs, carotid artery blockage and other cholesterol related vascular disease) has been discovered and utilizes a well known, broadly used antibiotic to kill the microorganism that causes vascular plaque buildup and other 'unwanted calcium' related conditions.

Can you tell me the procedure for filing such an application with the FDA - for "Off-Label Use" of a medication and where I can find a copy of the application form?

Thank you.

Moving this unsigned question here from the Helpdesk--inks 23:38, 1 October 2005 (UTC)

Most likely, your IRB is requiring you to submit an IND (Investigational New Drug) or NDE (New Drug Evaluation) application with the FDA [19] because your study does not qualify for a waiver. If you don't already know how to do this, you need help from someone who has experience with the process. It's not a task for the weak-hearted, and it can't be done on the basis of advice from Wikipedia! You can start by asking your IRB for additional information. You might also have a look at the FDA site. (I'm assuming you know about previously conducted studies which have failed to show benefit from antibiotics with regard to plaque; (2 studies were published in the April 21 2005 issue of the New England Journal of Medicine) - you'll need to include a literature review in your application.) [20] - Nunh-huh 01:30, 2 October 2005 (UTC)

You pick up the telephone and you call your hospital's IRB. You have to take a several hour course on ethics of human research in order to be a principal investigator for a research project involving people. Then you have to write up a description of your trial (the protocol) and a sample informed consent form. Then you make an appointment to present it to your hospital's IRB at one of their regular meetings. Be prepared to discuss relative risks and some skeptical questions if you are planning to offer your experimental treatment instead of a standard treatment. Remember, part of ethical resarch is designing a study that will have the power to provide a useful answer for the time, trouble, and potential risk of the subjects. What trial design did you have in mind? What recruitment method-- your patients, newspaper ad, referrals? I suspect I am not the only one who thinks anyone who is asking wikipedia how to do medical treatment research is pretty unlikely to know what he is doing or have the resources to do it, but we'll be happy to tell you the procedure. alteripse 01:49, 2 October 2005 (UTC)

Maybe, maybe not, but Wikipedia is already doing a service by pointing out what the procedures (and safeguards) are for those of us who will never actually conduct this research ourselves (but who might one day be invited to be a subject of it). Thanks to the knowledgeable contributers! Physchim62 13:58, 4 October 2005 (UTC)

convert 1 kilometer to miles[edit]

convert 1 kilometer to miles

The easiest way to perform these converions is to use Google - just type 1 kilometre in miles into the seach box, click "search", and you will get the result: 1 kilometer = 0.621371192 miles. Thryduulf 11:00, 2 October 2005 (UTC)

Molecular Biology Techniques / PCR[edit]

What is the use of Nonidet P40 or Tween 20 etc. detergents in Polymerase Chain Reaction?

AA

For samples that contain cells, a detergent will make the target DNA accessible by dissolving cell membranes. --JWSchmidt 20:12, 7 October 2005 (UTC)

Xenon[edit]

What are the main properties of Xenon? <--- click here

Have you looked at our Xenon article?-gadfium 07:46, 2 October 2005 (UTC)

neurons[edit]

can neurons regenerate? - anon

  • Very slowly and as far as I know only in young people. Perhaps our article on neurons has some more useful info or links. - Mgm|(talk) 11:06, 2 October 2005 (UTC)

Very hot area of research. There is now evidence that regeneration can occur in many types of human neurons, and even in adults, against general beliefs from observation of neuroscientists and doctors for most of the last century. You can find articles by searching medline or pubmed for "nerve regenertation". Even googling it gets lots of hits. alteripse 01:22, 3 October 2005 (UTC)

People often ask this in the context of re-growth of cut axons. In the PNS axons often grow back. In the CNS there is often scar tissue formation that blocks re-growth. --JWSchmidt 20:22, 7 October 2005 (UTC)

bermuda triangle[edit]

Perhaps you are looking for our Bermuda Triangle article? Thryduulf 10:57, 2 October 2005 (UTC)

SNP[edit]

what is SNP

To me it means the Scottish Nationalist Party, but the the SNP page gives several other uses as well. Thryduulf 13:50, 2 October 2005 (UTC)

How do the tiny flaps of gills enable the fish to absorb as much oxygen as possible?[edit]

Please tell me ASAP.Tdxiang 13:22, 2 October 2005 (UTC)

See Gills. Thryduulf 13:48, 2 October 2005 (UTC)

3D Shape Problems[edit]

what is the "End Area" of a 3d shape, can someone explain this term and also how do you find the End area of a Cuboid, triangular prism and cylinder? Also can someone please explain to me how do you find the width of any 3D shape? can someone please help me?

regards nmak3000

In general there is no such thing as the 'end area' of a 3D shape. However all the shapes you mention are examples of prisms (in the mathematical sense). Have a look at the definition. The end area of a prism is probably the area of the end, i.e. its cross-section. DJ Clayworth 15:51, 3 October 2005 (UTC)

Activation of Windows XP[edit]

Suppose you have an old computer, and you had to reinstall windows, but suppose you don't know where your activation code is??? Is there anyway to extract that information from the computer itself?? Or are you just out of luck, and have to go buy a new installation disk from microsoft?

Hmm, maybe this could help somehow: http://www.annoyances.org/exec/show/article03-200 ? Kieff | Talk 17:15, 2 October 2005 (UTC)

Are you looking for the Key Code? Because if it's not too old, then it should be on your Tower(CPU) and it should be green, and silver, If it's a Laptop then it might be under it, and be green and silver.

Hope this helps Lordned 16:39, 3 October 2005 (UTC)

This little program will do the trick: [21]. It gets your Product Key and even lets you change it if you want. It works on all versions of Windows. Enjoy. --pile0nadestalk | contribs 04:06, 5 October 2005 (UTC)

What are the cultural/ethnic considerations of clients with ESRD?[edit]

I'm not sure exactly what you mean by your question, but perhaps you can find some info at Chronic renal failure.

Dental polymers[edit]

I'm trying to find information on the use of polymers in denistry, but I'm unable to find any such information on either the Polymer or Denistry pages on Wikipedia. Any suggestions/information?

-Josh/Sycron

Deriving a logarithm series[edit]

How would one go about deriving the following logarithm series expansion?

ln((1+x)/(1-x)) = 2(x + (x^3/3) + (x^5/5) ... )

Thanks in advance! This has been bugging me all day!

This one isn't too bad, but it takes a couple of steps. Bear with me. Oh, and we'd better assume  x \in (-1,1). Now, then, first it'll help to split up the problem as follows:
ln(\frac{1+x}{1-x}) = ln(1+x) - ln(1-x)
Now we'll work on the second term, and later get the first from it. First, note that
\frac{1}{1-x} = 1+x+x^2+x^3+...
(To see this, just multiply both sides by 1-x.) Now integrating both sides from 0 to x gives:
-ln(1-x) = x+\frac{x^2}{2}+\frac{x^3}{3}+\frac{x^4}{4}+...
From this, replacing x by -x, we get
ln(1+x) = x-\frac{x^2}{2}+\frac{x^3}{3}-\frac{x^4}{4}+...
Which going back to the first equation gives
ln(\frac{1+x}{1-x}) = (x-\frac{x^2}{2}+\frac{x^3}{3}-\frac{x^4}{4}+...) + (x+\frac{x^2}{2}+\frac{x^3}{3}+\frac{x^4}{4}+...) = 2(x+\frac{x^3}{3}+\frac{x^5}{5}+...)
Hope that helps! -- SCZenz 20:40, 2 October 2005 (UTC)

ATP (adenosine triphosphate)[edit]

Since ATP is the direct source of energy for body cells, why not bypass the lengthy digestion and cellular metabolism process for carbohydrate breakdown and eat ATP directly?

  • because, if you ate it, it would pass through your digestive system and well, be digested, same thing with just about all your cellular components, you have to synthesize your own--172.208.123.70 21:39, 2 October 2005 (UTC)

It also costs thousands of times more than sugar or starch. alteripse 22:39, 2 October 2005 (UTC)

Mammalian metabolism tends to convert most dietary nutrients into the simple sugar glucose before it degrades it and captures the chemical energy as ATP (via NADH + H+). Hence a drink containing glucose is a perfectly acceptable way to provide the body with an energy precursor. I suppose it beats an iv injection of ATP !

Taylor series expansion in x-a[edit]

How would one expand g(x) = sin(x)\, in powers of x-pi\,? I have the solution to this, but I haven't been able to get there on my own. Any expanation with steps would be appreciated! Thanks!

Try letting y = x - \pi; \,, then using sin(x) = sin(y + \pi) = sin(y)cos(\pi)+cos(y)sin(\pi) = -sin(y) \,. Then do the usual expansion about y=0\,, and substitute back in what y is. Does that work? -- SCZenz 23:15, 2 October 2005 (UTC)
When in doubt, you can always go back to the most general definition of a Taylor expansion near ''x'' = ''a''\,:
f(x) = f(a) + f^\prime(a) (x-a) + \frac{1}{2} f^{\prime \prime}(a) (x-a)^2 + \ldots \frac{1}{n!}f^n(a) (x-a)^n + \ldots
Notice that this expansion is what you want for a = π and f(x) = sinx. Then
f(\pi) = \sin \pi = 0 \,
f^\prime(\pi) = \cos \pi = -1 \,
f^{\prime \prime}(\pi) = -\sin \pi = 0 \,
f^3(\pi) = -\cos \pi = 1 \,
f^4(\pi) = \sin \pi = 0 \,
Now we can see a pattern: these values of the derivative will simply repeat, and the Taylor series will be:
 \sin x = - (x-\pi) + \frac{1}{3!} (x-\pi)^3 - \frac{1}{5!} (x-\pi)^5 + \frac{1}{7!} (x- \pi)^7 \ldots
Which matches exactly the expansion of -sin(x - π), which is what you get with SCZenz's method. — Laura Scudder | Talk 23:34, 2 October 2005 (UTC)

glass that shifts from translucent to transparent?[edit]

I was wonderin what the type of glass that shifts from translucent to transparent is called. I am an currently designing my own house and am looking to include it in my plans. It is a glass that appears to be clear but when a switch is turned or the door it is made of is closed it becomes much like frosted glass, I have to assume that this is electrically induced, but you know what they say you do when you assume. An example os this the bathroom stall doors in the "Real World: Austin" house. I would greatly appriciate a name and if possible the website of the company that produces it. Thank you very much for any help.

70.22.39.248 23:20, 2 October 2005 (UTC)John

One would think they just stick a lightsource of some kind behind the glass, which allows it to change from transparent to opaque at the flip of a switch, probably normal glass would do--172.208.123.70 23:27, 2 October 2005 (UTC)

Actually, they are special materials (and a large window can cost as much as a human kidney on the black market!). Unfortunetly, our article on the subject is just a stub: Electrochromics. ? Kieff | Talk 00:11, 3 October 2005 (UTC)

what are possible health effects of drinking diet soda?[edit]

I already know how bad regular soda is (high calories, high sugar), but I don't know about any negative health effects of diet soda yet. Are there any? --Revoluci n (talk) 23:56, 2 October 2005 (UTC)

I think this might interest you: health effects of aspartame ? Kieff | Talk 00:13, 3 October 2005 (UTC)
Kieff seems to have it right, I was thinking of phenylalanine, but apparently aspartame is the compound based on that which is found in most 'diet sodas'. I remembered that on Coke cans here in Australia, they warn of the presence of phenylalanine.. perhaps Diet Coke may be useful to you? splintax (talk) 03:58, 3 October 2005 (UTC)
I believe that most sodas are moderately acidic, even the diet varieties, and the acid will destroy tooth enamel. See [22].-gadfium 01:22, 3 October 2005 (UTC)
I recall reading that some diet pop shipped to Arabia for the troops there was left out in the heat for an extended period and started changing into a nerve toxin slowly.
I'm pretty sure that was Methanol. I doubt our reader will be leaving his pop in the middle of a desert though. --Phroziac(talk)Flag of Phyzech Republic.svg 14:35, 4 October 2005 (UTC)
Diet soda has more caffiene then regular. --Phroziac(talk)Flag of Phyzech Republic.svg 14:35, 4 October 2005 (UTC)
Don't forget loads and loads of sodium, at least in many diet drinks.Brian Schlosser42 19:41, 5 October 2005 (UTC)

what are the four classes of organic compounds?[edit]

See Organic chemistry. The four classes would probably be Aliphatic, Aromatic and Heterocyclic compounds, and polymers. Although you might want to edit your question to be a bit more specific. splintax (talk) 03:54, 3 October 2005 (UTC)

what is miasma?[edit]

A very pejorative term for mist, or something bad suspended in the atmosphere. Among the politically correct, "special air" is now considered preferable. alteripse 01:05, 3 October 2005 (UTC)

Geometry Area or a Square[edit]

What is the area of the square ABCD that has a diagonal of length 12cm?

See pythagorean theorem, and note that a square is just two right triangles. -- SCZenz 01:24, 3 October 2005 (UTC)
More specifically, two isoceles triangles. --jpgordon∇∆∇∆ 03:09, 3 October 2005 (UTC)
I know I'm doing this person's homework for them, but just to clarify - I'll solve the problem. Squareness implies that all sides are equal in length. From Pythagoras' theorem we get:
a^2 + b^2 = c^2
Since c is the length of the diagonal (or the hypotenuse of the triangle inside the square), and a = b (because they are sides of a square), we can say:
a^2 + a^2 = 12^2
2(a^2) = 144
a^2 = \frac{144}{2} = 72
We could find the square root of 72 to find the side length of the square, but keep in mind that the area of the square is simply the side length squared. Therefore, the area of the square is 72. splintax (talk) 03:49, 3 October 2005 (UTC)

Hair texture[edit]

Humans evolve different traits according to their environment. For example, people who originated in places close to the equator tend to have darker skin, because it has more melanin and protects them from the sun and skin cancer. Why do black Africans (and I have also heard New Guineans and possibly other people that I don't know about) have curly hair that is so different from most other people who have straight hair (what environmental or other factors led them to develop this type of hair and why was it an advantage)? --KForce>(talk)</ 05:39, 3 October 2005 (UTC)

Did you read Hair? This quote may be helpful:
The diameter of a human hair ranges from about 18 µm to 180 µm. In people of European descent, blond hair and black hair are at the thinner end of the scale, while red hair is the thickest. The hair of people of Asian descent is typically thicker in diameter than the hair of other groups.
Cross-section shape of human hair is typically round in people of Asian descent, round to oval in European descent, and nearly flat in African peoples; it is that flatness which allows African hair to attain its frizzly form. In contrast, hair that has a round cross-section will be straight. A strand of straight round cross-section hair that has been flattened, for example, with an edge of a coin, will curl up into a micro-afro.
Hope that helps, although it doesn't answer your question completely. splintax (talk) 03:51, 3 October 2005 (UTC)
Now there's a nice eurasian-centric way of putting the question. Ever heard of the out of Africa theory? I assume we all had nappy hair once upon a time, but those who left Africa somehow lost that (I don't know why, though, sorry). Note that pubic hair also curls because it is flat. One might conclude that blacks have pubic hair on their heads, but it would make more sense to say the rest of us still have nappy crotches :) . DirkvdM 14:11, 3 October 2005 (UTC)

Ok, I am very familiar with the out of Africa theory, and perhaps I asked the wrong question because I agree, that was a very eurasian-centric way of putting it. Ok, so going from an out of Africa view, why did people from everywhere else develop straight hair where the shape of the hair is round, rather than curly hair where the hair is flat? --KForce(talk) </16:00, 3 October 2005 (UTC)>

One possibility is that a variety of hair textures serves simply to help identify people. Different eye color, for example, doesn't appear to serve any purpose other than to aid in identification. There might be biological advantages to some hair textures over others in each environment, as well. A large "afro" would be good in hot weather, as the heat would be created when light strikes the hair far from the scalp, and thus would limit heating of the brain. In cold whether, hair that lies flat may be better, allowing more of the heat to transfer to the brain. StuRat 07:43, 9 October 2005 (UTC)

can birds fly in vaccum[edit]

No. See aerofoil and bird flight. Guettarda 05:28, 3 October 2005 (UTC)

Not to mention that birds breathe. -- Jmabel | Talk 05:29, 3 October 2005 (UTC)
What about in free fall, I wonder if any birds have been taken to orbit? --WhiteDragon 16:56, 4 October 2005 (UTC)
I guess nobody knows, but it would probably be very confused. A bird in zero-gravity would probably experience that it were falling, but it would feel no wind and probably have no feeling of up and down. It might try to fly in the direction it would percieve as "up", perhaps changing direction all the time. Or it might simply sit (or float) still. It would definitely have a hard time trying to maneuvre. It would be very interesting to see if a bird could adapt to zero-gravity conditions.
Not to mention that their loungs, blood vessels etc. might break or even explode because of the low pressure in a vacuum.
Actually, I remember reading at one point that NASA scubbed a part of a mission that was to include taking birds into orbit. Birds lack the muscles in their necks necessary for peristalsis, so they would have died from dehydration/starvation. Guess we'll never know. --Michael 04:22, 9 October 2005 (UTC)

blood vessels in eyes[edit]

When you look at a human eye, there is the inner part which is colored and the surrounding area which is white. However in the white part of your eye, you can often see red blood vessels. It appears that sometimes you see more of them than other times (when there are a lot of them, I think it's called blooshot eyes?) What causes these blood vessels to appear more at certain times, is it a sign of an unhealthy eye, and what can be done to prevent lots of blood vessels from appearing or to make visible ones go away? --KForce 05:38, 3 October 2005 (UTC)

Many reasons, one of which is Conjunctivitis. --hydnjo talk 06:00, 3 October 2005 (UTC)
Your body has the ability to have each blood vessel and capillary contract or expand as needed. Only those close to the surface are visible, however, causing blushing and bloodshot eyes, for example. One should be careful to distinguish between cause and effect here. Some irritation or infection of the eye creates a need for increased blood flow to bring white blood cells, etc., to the area to repair the damage. So, bloodshot eyes aren't the "disease", they are the "cure". It's true that they are unsightly, but it's best to leave them bloodshot long enough to fix the problem rather than using a product which will cut off the needed blood supply (the most famous being "Visine - gets the red out"). Of course, identifying the source or irritation, such as smoke, lack of sleep, eye strain, etc., and eliminating it, will be best in the long run. StuRat 07:29, 9 October 2005 (UTC)

What is analog telephony and its chief concepts?[edit]

Looks like a homework question (do your own). Telephony is that which is based on or related to telephone communication, and analog is not digital. That said, check out Category:Telephony and the "See Also" section of the Telephone article. — Lomn | Talk / RfC 15:01, 3 October 2005 (UTC)

Tired legs[edit]

I know this may not be the best place to ask this question, but before going to a physician I wanted to hear your opinion. I'm a 19 year old frequent sportist (mostly upper body strength, rarely cardiovascular exercise) and, since this summer when, after playing more than 2 hour long everyday soccer matches I've been experiencing lack of strength and sometimes even pain after doing basic leg exercises, such as running or jumping. Do you have any idea of why can be this happening? PD: Sometimes, while on computer, I experience a tingling sensation in my legs.

Thank you in advance.

Seems like a normal excercise pain to me. I'm pretty sedentary myself, and I get the same simptons whenever I ride a bike for a few kilometers or play soccer for an hour or two. But I'm no physician, so remember Wikipedia:Medical disclaimer. ☢ Kieff | Talk 11:36, 3 October 2005 (UTC)
A medical discalaimer on Wikipedia?? Get real! Anyone who thinks that Wikipedia can serve as a substitute for a physycian really needs to see a doctor - just of a different kind :) . DirkvdM 14:41, 3 October 2005 (UTC)

The differential diagnosis for this symptom is lengthy and ranges from trivial to slowly catastrophic. See a doctor but before the visit try to think of objective evidence for a real change (e.g., substantial difference in how far you can walk, bicycle or climb stairs compared to 6 months ago) rather than subjective differences (I feel more tired when I...). Second, think about whether this is just a leg problem, or leg and foot, or whole body strength change. Third, your doctor will be trying to distinguish between subjective versus objective weakness, earlier fatigue versus decreased strength, localized versus generalized weakness, strength only changes versus strength plus changed sensations. Fourth, think about any other new symptoms or body changes, especially those present for the last few months. Good luck. And for the potential hypochondriacs out there in audienceland, I would like to emphasize that purely subjective changes in strength and energy rarely signal serious disease.alteripse 16:21, 3 October 2005 (UTC)

reasons for hair loss for male in the age group of 18 to 20[edit]

See alopecia. Differential diagnosis depends on pattern and degree of loss (i.e., visible bald areas versus more hairs in the shower drain or brush) and ranges from perception to normal androgen effect which will culminate in male pattern baldness to a variety of less common causes of localized hair loss to (rarely) some systemic (whole-body) diseases of metabolism or nutrition. Good luck. alteripse 16:27, 3 October 2005 (UTC)

If you join the military, you will get a hair cut. There are military reasons why short hair desired: uniform standardization; in hand to hand combat, more difficult for enemy to grab you by the short hairs. AlMac|(talk) 03:37, 5 October 2005 (UTC)

the line between night and day[edit]

Is there a name for the boundary of the shadow that turns night into day? I thought there was, but it's not mentioned in either article. -Lethe | Talk 15:30, 3 October 2005 (UTC)

I believe it's most commonly called the terminator. — Lomn | Talk / RfC 15:34, 3 October 2005 (UTC)

acre as distance between gas wells[edit]

It is said that the distance between gas well drilled in the Barnett Shale in Texas must be twenty acres. If an acre is a measure of area, how is the distance between these wells determined?

<email removed>

You shouldn't put your email on this page, as everyone in the world will read it and send you spam. Replies will be posted on this page, not to your email address.
Probably this means that every gas well should be on a piece of land of twenty acres without another well on it. Givng the separation this way allows for easy calculation of how many wells you can put on a piece of land. DJ Clayworth 15:45, 3 October 2005 (UTC)
On the other hand, it doesn't prevent you having your twenty-acre plots be very long and skinny, and putting your wells ten feet from each other in a row. I think official idiocy is the real reason. PeteVerdon 11:42, 7 October 2005 (UTC)

C++ tutorials?[edit]

Can someone give me a link to a free, online, C++ tutorial, that starts from the very basic? Or some tips abouat C++

Any help appreicated Lordned 16:35, 3 October 2005 (UTC)

PS. Does anyone know what "Iostream" means?

It's Input/Output Stream, one of the basic I/O libraries for C++. — Lomn | Talk / RfC 17:22, 3 October 2005 (UTC)
I'd recommend "Thinking in C++" by Bruce Eckel, available at www.mindview.net. It's for people who have some experience of programming in any other language; if you've never programmed in anything, then I wouldn't recommend C++ anyway.-gadfium 21:54, 3 October 2005 (UTC)

Well i have the basics of C++ down. Took a week long class, at a camp.

 -Lordned

how the length of a wire affects its reesistance[edit]

It's linear. — Lomn | Talk / RfC 17:23, 3 October 2005 (UTC)
Resistance of a wire = (length * resistivity) / cross-sectional-area →Raul654 19:12, 3 October 2005 (UTC)

What are the Dymanics of Smoke?[edit]

Does it rise? Fall? Disperse? etc.

Well, obviously it rises first (ceterus paribus), but I suppose you mean after it has cooled down. And I suppose that depends on it's chemical structure, but I'm pretty sure that most smoke particles are heavier than air and will therefore fall. If neither shaken nor stirred, that is, and for that you'd need laboratory circumstances. Otherwise they'll just float about until they stick to something I suppose. Not that I actually know, by the way.... :) DirkvdM 18:55, 3 October 2005 (UTC)

Light Filtering[edit]

Is it possible for a static light filter in the form of a single piece of glass, lexan, polycarb, etc. to defer brighter light in greater proportion than softer light? I am asking specifically regarding applications in vision augmentation like sunglasses or larger shields, interested in knowing if a specific filtering process is better or worse for high-light/low-light situations. I know about LCD based active filters, and various aspects of polarized filtration, neither of which are exactly what I'm interested in. TIA! --Jmeden2000 17:29, 3 October 2005 (UTC)

  • No truly static device can do what you want. A saturable absorber (man, that's a bad article) is the closest in concept. Generally, this sort of thing is called an "optical limiter" and there are various organic dyes that work this way, with various drawbacks. I know at least one brand of sunglasses (Reactolite Rapide) that used them. -- Bob Mellish 17:49, 3 October 2005 (UTC)
    • Damn, that article was crappy. I had to tweak it a bit, it looks like a proper thing now. I also redirected to the appropriate location. ☢ Kieff | Talk 17:58, 3 October 2005 (UTC)
      • Actually, I had a braino there. A saturable absorber is exactly the opposite of what the OP wanted. An optical limiter is correct (increasing absorption with increasing intensity). Still, thanks for sorting out that stub, which it sorely needed. --Bob Mellish 18:07, 3 October 2005 (UTC)

Stress fracture[edit]

You're not wrong. See Stress fracture. Proto t c 13:28, 4 October 2005 (UTC)

what causes food decay[edit]

Any of a variety of bacteria and fungi spores commonly present in the air start digesting the food, and it degeneratres (as well as the bacteria and fungi themselves not being very edible). --Borbrav 00:33, 4 October 2005 (UTC)

Aerodynamics of Birds[edit]

hi,

   I am entering a scince fair and I need a few pictures of wind diagrams of bird wings!
                    ,--Jake Haines 18:51, 3 October 2005 (UTC)


2 Windows Xp os'[edit]

OK, I'm sure the title could have been a little more descriptive, but... here's my situation:

I have 2 XP's loaded on my hd for some reason, at start-up i get the screen to select which one to boot from, one works, the other doesn't. How to I get rid of the one that will not boot? I want to get it of my hard drive all together, how would I go about doing that?? john


I am new to this Wiki site,

But I may be able to point you in the right direction with regards to your double os selection.

You can remove the non-working option from the start up by editing the system start up file. One way to do this would be to right mouse click on My Computer, goto properies, select the Advanced tab, click on the settings tab under Startup and Revovery. Now you will have the option to Edit the start up options manually by clicking the Edit button. This will open up a text document with the operation systems listed here. As for which one to delete I cannot remember please seek further help on what to do next Be warned I am sure that if you delete the wrong line your system will not boot because you will be left with the system that doesn't work. There is probably more information about this but I hope this helps.

Gezzabob 22:26, 5 October 2005 (UTC)

Difference between "Applications" and "Services" Concepts in Computer Science[edit]

Many organizations are adopting Service Oriented Architectures (SOAs) to increase interoperability and software reuse. Software developers used to refer to their products as "Applications". With the new "Services" approach, is there an agreed upon definition/distinction/relationship between the terms "Application" and "Service"?

Carl Prantl

An application is a piece of software, a service is the task that that application performs. Think of it this way - TCP/IP is the application, but the service it provides is reliable data transfer across a network. →Raul654 19:10, 3 October 2005 (UTC)
I believe their is a different business model behind the two terms. If your group supports a certain "application" that implies they are tied to a strict set of software, whereas if they support a "service", they may be more flexible, by developing their own software, contracting out that development, or using off-the-shelf products to provide the same service more efficiently for less money. StuRat 07:16, 9 October 2005 (UTC)

Why are most metals cold to the touch?[edit]

I understand because they conduct heat away more efficiently than other materials, but is there a more scientific explanation for this? - Cobra Ky Flag of the United States.svg (talk, contribs) 19:11, 3 October 2005 (UTC)

That's pretty much it, as far as I know. If a metal is colder than your skin, it conducts heat away faster and feels cold; if it's warmer, it conducts heat to you faster and feels quite warm. Also, metals cool down (and warm up faster), so they may actually be cooler (or hotter) than other objects if there's been a recent temperature change. If they have direct sunlight on them, of course, they absorb that energy quite efficiently and become very hot. -- SCZenz 19:44, 3 October 2005 (UTC)

Thanks for your swift answer. But what is it ABOUT metal that makes it conduct heat faster? What is it in the chemical composition that causes this? - Cobra Ky Flag of the United States.svg (talk, contribs) 19:50, 3 October 2005 (UTC)

The atoms in a metal are close together and strongly bound to one another: for most metals, the atoms are packed as closely together as possible. Vibrations of one group of atoms are rapidly transmitted to the other atoms in the object (this is how heat, and sound, are conducted). The links between individual molecules in, say, wood or plastic are weaker and the transmission of vibrations is less efficient: hence their thermal conductivity is lower. Physchim62 20:26, 3 October 2005 (UTC)
Ah ha! Thanks, that makes perfect sense. - Cobra Ky Flag of the United States.svg (talk, contribs) 21:12, 3 October 2005 (UTC)

I think that electron structure is probably more important for explaining thermal conductivity than bond strength. Atomic bonds in metal are not particularly strong, so that explanation needs some work. See thermal conductivity for more on the subject. Apparently it's a complex question. -Lethe | Talk 00:00, 4 October 2005 (UTC)

Eye fatigue[edit]

Can being in front of a computer screen (2 feet from screen) damage your eyes if used for an extremely long time? any difference between LCD and CRT screens?

Probably not permanent damage. It can definitely cause strain and discomfort, however. Remember that your doctor, not Wikipedia, is the best place to go for medical advice. User:Nightvid
I'm no expert, but here's what I think I know. I can think of two reasons an LCD would be safer than a CRT. One is radiation, of which an LCD doesn't transmit any, afaik. CRT's are shielded somehow and there will likely be big differences between different screens. I'm surprised to see the manual to my monitor doesn't give any info on that. Just that it's TCO'99 compliant. Alas the TCO Certification article is just a stub and I haven't found a better source just yet. The other thing is the strain Nightvid mentions, which I believe is caused by flicker, which at least partly has to do with the refresh rate a monitor can handle. This you might measure by using a screen for a whole day. If that doesn't give you a headache it's probably a good screen. LCD's have a slow reaction, which is bad for gamers but good for your eyes. And just as too much reading (with bad light and such) can be bad for your eyes, I suppose this can have a permanent effect.
By the way, is a doctor the best source for info in this? It's not about a specific personal ailment but about something general, so there should be some general info somewhere. I just don't know where. DirkvdM 09:23, 4 October 2005 (UTC)
I not know the correct terminology for some of this, but
you can get a prescription from the eye doctor to optimize your vision for a particular distance, like how far your head is normally from computer console (which is different for me at home and at work)
I think the current monitor standard is SVGA ... anyhow I went with a higher standard because the bigger the screen and the smaller the pixels the crisper the image, and on some OS you can adjust the size of the characters (think how many characters sideways and how many vertical) ... so basically it is like looking at a good book, or a fuzzy picture, or some place in between.
Look at telephone yellow pages ... black print on yellow background is easiest to read, but what about what is around what you looking at ... the entire vision contrast impacts usability or readability.
What kind of lighting do you have? You want to avoid any glare on the screen If you are in an office, often there are those blue lights in long translucent tubes (I forget the name ... fluorescent?) anyhow depending on where they are relative to your monitor, their flicker rate can interact with the computer monitor flicker rate to the detriment of your vision. Ideally you want to be positioned so that they run down the side of your work area paralleling the direction that you are looking in. You do not want them directly overhead of you or your monitor. You do not want to be sitting with them side to side relative to your desk. Typical work place you not have a choice in matters of ergonomics.
(and does it need cleaning?) When I get in my auto sometimes my glasses are misted up, and sometimes the windshield is misted up, and I need to wipe both sides of both to get a clear unfuzzy image ... well your computer monitor is like that, only simpler.
Also review keyboard and seating. Is your hand at a comfortable height? Are you keying kind of hunched over, so you get back pain? Are you keying so your hands are uncomfortable ... do you know what causes carpal tunnel syndrome? I think heavy use of mice contributes a bit to this.
Some Internet sites are designed so as to be hostile to some users. For info on this problem with some Wiki pages, see Wikipedia:WikiProject Usability.
AlMac|(talk) 03:44, 5 October 2005 (UTC)

Ginger[edit]

How is ginger harvested or processed?

Ginger is picked by hand; see [23] for a description of post-harvest processing. Gdr 21:24, 3 October 2005 (UTC)

Just a Thought/Gravity[edit]

I am a bit simple and find it hard to follow articals on physics when mathmatical formula are used. I understand that maths is the language of physics but as soon as the numbers come up it might as well be written in another language. Anyway I'm going to attempt to ask a question which I hope doesn't sound to stupid and I hope some one can answer it in a way that I can under stand.

The question is about the speed of gravity. I read that two heavenly bodies ie. earth and moon, are tied together by the pull of gravity and that if one of these bodies were to instantly vanish then the gravitional pull between them would also vanish instantly. This affect would be instant regardless of the distance between the two heavenly bodies. The argument also exists that nothing can travel faster than the speed of light. So there is a conflict between the two schools of thought.

My question is probably answered in some mathmatical jargon some where but.... if gravity existed as a sort of cloud around a heavenly body and another heavenly body in that cloud were to vanish what sort of affect would that have on the heavenly body that stayed behind? Or to look at it another way, if I pulled a pebble from the ocean would any of the other pebbles in the ocean notice?

The vanishing object would suffer a collapse of it's gravitional field and the remaining object would continue to exert the same degree of gravitional pull as it's own mass would allow. The only thing to change would be the interaction between the two.

The question then is is an interaction an actual physical thing in it's own right? I can interact with another person in a room with out any direct transfer of energy between me and the other person. A wink or jesture could transfer information either locally or across streets or fields and should the other person vanish my own condition would remain the same.

I'm not realy sure about the whole argument because in order for the moon to be released from the pull of the earths gravity the earth would have to vanish...which ain't going to happen...not in this universe.

I don't think this is realy a question but more like just a thought which I hope more learned people will comment onEye 22:14, 3 October 2005 (UTC)

Just a quick anser, the effects of the "vanishing" would not be felt instantly. I'll let someone else explain this bit better because I couldn't put it in a simple way. But see: gravity, graviton, gravitational wave. ☢ Kieff | Talk 23:03, 3 October 2005 (UTC)

According to Einstein's model of gravity, changes in the gravitational field propogate at the speed of light. In Newton's theory, changes propogated instantaneously. Newton knew this about his theory, and disliked it, as have most people since. Now that Newton's model is 400 years old, and we have a more accurate model, there really isn't any school of thought that says changes in gravitational field are instantaneous. -Lethe | Talk 00:08, 4 October 2005 (UTC)

Yes, changes in gravity propagate at the speed of light. However, it is meaningless to talk about a "body", eg. a star, vanishing. A body can move and its matter can turn into energy, but the gravitational mass will remain unchanged. I know of no process that can make (relativistic) mass vanish.

OK! So I'm 400 years out...I'll catch up...eventually?

Einstein's General Relativity saids that space-time continuun is simply a piece pf fabric, when there is a massive object in space-time, it will curve the fabric of space time, like a bowling on a piece of rubber sheet. The earth keeps its orbit because the sun curved the space nearby, forcing earth to follow "the trace" that the sun had curved. Light travels at 300000m per second, and since only light can maintain the speed of light, gravitational waves cannot act instantaneously if the sun suddenly disappears. Since light takes 8.3 minutes to reach earth from the sun, the "vanish" of the sun will not act instantanesouly.

compander 'mu' law in digital quantizer[edit]

in digital quantization of a signal for a 'mu' =255 compander does the value 255 come from the sum of the number of representation levels that are available to represent the input or does it come from some other interpretation ??

--203.200.95.130 22:22, 3 October 2005 (UTC)

Visible cloud in front of a turbofan engine[edit]

File:Intake vapor.jpg
The cloud looks like this.
A similar cloud caused by a sonic boom.

I saw a lens-shaped cloud formed in front of a Boeing 777's cowling edge when the airplane was taking off in a foggy night. I don't know what caused it. So far my best guess would be the cloud was caused by the over-ingestion of air by the huge engine during the first several minutes (low pressure -> drop in temperature -> condensation). Am I right? -- Toytoy 23:21, 3 October 2005 (UTC)

Well, I'm not sure I can agree with your "over-ingestion" statement. But yes, I think if the air is speeding up in front of the intake, one would expect, due to Bernoulli's Principle a drop in both temperature and pressure, and if the air is already very close to the dewpoint, condensation causing a cloud. A similar effect causes condensation at the centre of wing-tip vortices (on which I can't believe we don't have an article! Though we do on wing tips and vortex). moink 08:35, 4 October 2005 (UTC)
Wingtip vortices has the article :) Yours is now a redirect. — Lomn | Talk / RfC 15:01, 4 October 2005 (UTC)

running windows xp pro on a network[edit]

I have six(6) computers,used for small internet business. i want to purchase a licensed MS Windows XP pro. My question is: Is it legal to install a single OS to the entire local area network? 203.87.201.246 00:06, 4 October 2005 (UTC)

No, it's not legal. Microsoft requires you to have either an individual license for each computer (volume licensing starts at 5 units, so you could check that out) or a site license. — Lomn | Talk / RfC 00:10, 4 October 2005 (UTC)
What's more, I believe XP will check if other machines on the LAN have the same serial number, and if it finds a duplicate refuse to work properly. -- Bob Mellish 00:18, 4 October 2005 (UTC)
Actually, XP doesn't check on serial numbers (large corporations use a single serial number for all installations), but it does check that the machine names and security Ids are unique on the network. This last is only an issue if you use disk cloning to set up your machines. If you install each machine separately, the network will have no problems, but Microsoft will start asking some hard questions when you try to register the copies.-gadfium 03:40, 4 October 2005 (UTC)

Bursting[edit]

How does bursting speeding up processing work?

have you checked Burst_mode? or done some general searching on wiki first? Boneyard 09:24, 4 October 2005 (UTC)

WHAT MAKES THEM GOOD??? (TFT-LCD, CRT)

is it true that the cophixalus exiguus by passes the tadpole stage?[edit]

yes

Health effects of tea vs. coffee?[edit]

My grandfather, a retired doctor, used to tell me that tea was a lot less harmful to drink than coffee, because it contained theine as opposed to caffeine. He claimed that tea would keep you awake but not "jittery", and would let you down from the high gracefully, whereas coffe would cause you to "crash". The article on caffeine appears to refute all of this.

So, what's the deal? If I want a beverage that keeps me alert and gives me the drive to, well, edit Wikipedia instead of working, is there any advantage (or disadvantage) to drinking tea as opposed to coffee? --Ashenai (talk) 11:17, 4 October 2005 (UTC)

  • Caffeine is known to keep you alert and coffee usually contains lots more of it than tea, so coffee or if you can afford it a equivalent volume of Espresso is sure to keep you up. Additionally sugar keeps your brain active. - 131.211.210.14 12:51, 4 October 2005 (UTC)
  • Caffeinated drinks hit different folks differently, so I'd advise you to experiment, say a week at a time on coffee, black tea and green tea. My own experience is in line with your grandfather's advice, but lots of folks handle coffee much better than I do. One caveat: many coffee shops make crummy tea. You need to see the bag doused in water from a boiling kettle or, second best, the scalding tap from the espresso machine. If they hand you a cup of lukewarm water for you to drown the bag in later, that ain't tea. Oh, and our caffeine article says that theine is caffeine. Sharkford 14:09, 4 October 2005 (UTC)

Lost my USB ports[edit]

Hi, I have my internet connection shared from in a LAN setup at home and today when I went to try get on the net I couldn't. Well I investigated a bit and found out my svchost wasn't operating. I did a "repair" from the windows CD (i'm running XP btw) and that fixed the LAN up fine. But then I released I'd have to reinstall service pack to again to get back USB 2.0 (which was wierd because in the control panel the windows firewall was still visible). Anyway I reinstalled that but after it had completed and I had restarted I lost all my USB ports. Device manager says that this device is working correctly, however none of my USB devices are working (including my mouse). Obviously working without a mouse is a big pain so I dug out my little green convertor and stuck the mouse into the PS/2 port and tried that. Still nothing. Can some please help my get back my USB!! --Fir0002 11:25, 4 October 2005 (UTC)

Well, I don't know about your USB ports, but bear in mind that your mouse won't be detected on the PS/2 port unless you restart your computer. --David Wahler (talk) 13:03, 4 October 2005 (UTC)

Q about astronomy[edit]

When looking at the night sky, are all the stars that are visible with just the naked eye, from our own galaxy? Mortene 13:28, 4 October 2005 (UTC)

Yes and No. If you are in the Southern Hemisphere, you will be able to see the Large Magellanic Cloud and the Small Magellanic Cloud, which are separate galaxies. All over the world, you can see galaxies with the naked eye (if you are in a place with low enough light pollution) but you would probably think that they are single stars.... Physchim62 13:49, 4 October 2005 (UTC)
The Andromeda Galaxy is also visible to the naked eye, as are other members (those more closely related to the Magellanic Clouds) of the Local Group. I suspect the "yes and no" of the previous answer largely relates to the fact that while you can see extragalactic stars, you can't see individual extragalactic stars. However, the interesting case of Andromeda is that, around 120 years ago, a single extragalactic star (supernova S Andromedae) became naked-eye visible with a magnitude of 6. — Lomn | Talk / RfC 14:58, 4 October 2005 (UTC)
Thanks for the replies! Very interesting, and just the kind of response I was hoping for. Mortene 07:45, 5 October 2005 (UTC)

what is operating system[edit]

The system that allows a computer to operate. See Operating system. Proto t c 14:21, 4 October 2005 (UTC)

In simple terms, the interface between the hardware and the application software. Microsoft Windows is perhaps the most popular. You get the Personal Computer Hardware, the OS is installed on it, then various programs like e-mail and word processing is installed to run on the OS. AlMac|(talk) 15:19, 8 October 2005 (UTC)

glaciers in the ice age.[edit]

I have always heard about the glaciers that covered the northern part of the continent during the ice age, and how they transported rock and debris south, or dug out the great lakes. Living in Michigan, I can see where they left moraines. However, I have never heard a good explanation as to the force that propelled these glaciers forward. There is no real elevation gain from Michigan to the North Pole. It's not like these gaciers were flowing downhill like they do in mountainous regions.

Glaciers move by the influence of pressure and gravity but not from the direction of the North Pole southward. They follow the local contours of the land they are on. Pile anything high enough and it will eventually move outward and downward. Glaciers care not for north or south (or anything else for that matter) but simply form and move based on local conditions and forces until they retreat, also because of local conditions. So, basically, in an ice age the local conditions become favorable for the formation of glaciers over a much larger area of the world. They did not move southward, they formed further and further south as the conditions "worsened". Qaz (talk) 17:59, 4 October 2005 (UTC)
If that were true, how do you explain glacial moraines, glacial erratics, rock scouring, etc. Clearly during the ice ages, glaciers both expanded and moved. Part of this can be attributed to elevation changes and some simply to the weight of the glacier causing it to spread at the edges. In some parts of North America, the land is still rising from weight of the glaciation that ended 10,000 years ago. Rmhermen 23:12, 4 October 2005 (UTC)
My point was not that glaciers did not move. My point was that when they did move it was not in a wholesale way from north to south. Glaciers do move and that movement causes many geologic features but glaciers move not away from the poles but based on local conditions. They are much like rivers; there is no preferred direction for rivers to flow except to lower elevations. In the ice ages the climate was much colder in North America so there were glaciers at what we consider very southern latitudes but they did not come down from the poles. They formed locally and moved just like mountain glaciers do, mostly downhill. The major difference between a valley/mountain glacier and a continental glacier is scale. All the same principles apply. Qaz (talk) 05:09, 5 October 2005 (UTC)
I suppose this talk about local glaciers forming is about mountainous areas. In the Netherlands we have a big pile of sand called the Veluwe that was formed because it at the edge of the icecap. And the Netherlands being (and always having been) flat, I suppose the movement was southward. Another thing I suppose is that all those lakes in the north of the Netherlands (and in Finland, which is also flat) were formed by the weight of the ice. DirkvdM 12:33, 6 October 2005 (UTC)
Are you sure that the area was not made flat because of glaciation? Qaz (talk) 17:30, 6 October 2005 (UTC)
Actually I looked into it and there are other reasons for the Netherlands being so flat but glaciation can tend to level an area which is why I was wondering in the first place. Qaz (talk) 04:15, 7 October 2005 (UTC)

Michigan was at the edge of the Laurentide ice sheet that created the Canadian Shield, so you need to read the ice sheet article which explains how such large masses of ice were able to move. The force that pushed the ice sheet was of course the enormous weight of the ice. Gdr 20:38, 6 October 2005 (UTC)

One thing that is difficult to visualize is that ice under pressure behaves like a fluid, not like a crystaline solid. That is, it flows like thick gelatin. You can create a small scale model by putting jello on a large plate. It will slowly spread out in all directions, especially if you keep adding more to the top to simulate snowfall. StuRat 06:58, 9 October 2005 (UTC)

Reaction of vinegar and bicarbonate of soda.[edit]

In the reaction of sodium bicarbonate with acetic acid, forming sodium acetate, water and carbon dioxide (NaHCO3 + C2H4O2 => CH3COONa + H2O + CO2), I read that the molar mass of acetic acid is 60.05 g/mol, and that of CO2 is 44.01 g/mol. Also, the formula weight of sodium bicarbonate is 84.0 amu and the molecular weight of sodium acetate is 82.0 amu.

I wish to derive a recipe for creating carbon dioxide. From the above information, how can I determine the relative quantities of vinegar and bicarbonate of soda to use so that all the powder C2H4O2 is dissolved by the liquid NaHCO3?

And how can I calculate the ammount of CO2 which would be generated? --- Snonskoid

What you need to do is examine reaction masses. One part NaHCO3 and one part C2H4O2 makes one part CO2 (by mole, not by mass). You can disolve all the C2H4O2 by using entirely too much NaHCO3, but this is obviously inefficient. Instead, match molecular parts for the most efficient method. Then calculate the generated CO2 by the same method. — Lomn | Talk / RfC 18:17, 4 October 2005 (UTC)

binary liquid explosives[edit]

what are binary liquid explosives and what are the chemical structures--195.93.21.103 16:36, 4 October 2005 (UTC)

As far as I'm aware binary explosives are those that are stored as two non-explosive chemicals which are then mixed just before detonatition to produce explosive. I don't know enough about them to chemical information. Robmods 17:47, 4 October 2005 (UTC)

  • Any reaction with high gas production will cause the capsule to explode, because the gasses won't fit in it anymore at some point. Most of such reactions are exothermic as well. - Mgm|(talk) 21:58, 4 October 2005 (UTC)

Mona Clonal Antibodies?[edit]

What are the potential moral implications of their use?? Is it really appropriate to use them? Taking one life to save another? how is this justified? and why is there no article on the subject monaclonal antibodies, mona clonal antibodies, even monaclonalantibodies are all redlinked, looks like someone is afraid to have this argument--WwJd 16:47, 4 October 2005 (UTC)

I believe you have misspelled monoclonal antibody. — Pekinensis 16:57, 4 October 2005 (UTC)
That doesn't change the ethical considerations? now does it?--WwJd 17:16, 4 October 2005 (UTC)
Well, it does invalidate your "too afraid to discuss this" comment. Also, I fail to see anything about taking lives in our article. Could you elaborate on your concerns? — Lomn | Talk / RfC 18:12, 4 October 2005 (UTC)

There is nothing unethical about monoclonal antibodies. They are not made from fetal tissue. They are most commonly generated in a laboratory. alteripse 21:39, 4 October 2005 (UTC)

  • And that makes it alright? Growing unborn children from cloned tissue just so you can harvest their antibodies is hardly as 'harmless' as you make it sound, are they really any less human just because they've been cloned?--WwJd 22:12, 4 October 2005 (UTC)
    • Um, I think the point that Alteripse is making is that producing monoclonal antibodies does not require cloning fetal tissue. Are you sure you not confusing monoclonal antibodies with embryonic stem cells? -- Bob Mellish 22:23, 4 October 2005 (UTC)
      • If they made monoclonal antibodies from humans I suppose it might be unethical. Especially the final bleed. David D. (Talk) 22:36, 4 October 2005 (UTC)
      • I thought I gave a straight answer. Monoclonal antibodies are copies of human antibodies generated in laboratories and factories. Are you just here to pick a fight? alteripse 22:50, 4 October 2005 (UTC)
        • Looking at his contribs, quite possibly... Shimgray | talk | 00:13, 5 October 2005 (UTC)
          • Perhaps the editor needs to be directed to a discussion forum or a chat board or something. --jpgordon∇∆∇∆ 00:23, 5 October 2005 (UTC)
  • I can see I'm outnumbered--WwJd 03:19, 5 October 2005 (UTC)
Make that outwitted. DirkvdM 12:38, 6 October 2005 (UTC)

Agreed. Your premise that a life is taken to save another is just plain wrong, no life, even the life of a fetus, needs to be taken to produce monoclonal antibodies. And as for the redlining of the links, that's only due to your atrocious spelling. StuRat 06:43, 9 October 2005 (UTC)

Asteroid Belt aroun Earth[edit]

I had read somewhere that the Voyager missions detected a very faint ring around earth. Is this true?

It wouldn't be Voyager (those missions are to Jupiter and beyond), and it wouldn't be anything like an asteroid belt. However, scientists do believe they have observed very faint dust clouds at Earth's L4 and L5 (Trojan) Lagrange points (with respect to the Moon), akin to the collection of space debris at Jupiter's Trojan asteroids on a much smaller scale. They're known as Kordylewski clouds. If Earth had a natural ring, it would orbit around 20,000 miles up (inside the Earth's Roche limit) and would be easily observed. Check out Asimov on Astronomy (it should be available via your local library) for more on this. — Lomn | Talk / RfC 18:08, 4 October 2005 (UTC)

my dream[edit]

can i get addmission latest by jan2006.?

Please re-state your question. Admission to what? — Lomn | Talk / RfC 18:11, 4 October 2005 (UTC)


Death[edit]

I am doing a research paper on death and its connection to a possible aferlife.My question is: Who is the author of the article titled Death, and who are their sources? I am quoting the article because i found it interesting and need the information for my bibliography. One last thing, has anyone ever been able to prove the existance of alternate dimensions or an afterlife, solid evidence? If anyone could help me i'd appreciate it.(make sure you won't mind if i quote you in my research paper) This paper determines my semester grade (i'm a high school senior) so i'd appreciate any info such as credible sources about death or the afterlife, from any viewpoint (medical,spiritual,theoretical, religious, ect...) thank you

For the first question, see Wikipedia:Citing Wikipedia. Frencheigh 18:40, 4 October 2005 (UTC)
That is not a scientific or mathematical question! From Christian point of view, Afterlife would be( if you were a Christian) to go to Heaven and be with god for eternity, not hell.
--Jake Haines 18:42, 4 October 2005 (UTC)
For the second, no conclusive evidence has ever been found either way, and there is no likelihood of such evidence being found in the forseeable future. (Connie Willis' novel Passage is about a researcher studying near-death experiences, and has a few trenchant comments about the problems of working in this field; it's not one where productive research is easy) Shimgray | talk | 18:44, 4 October 2005 (UTC)
If life after death were proven beyond doubt you'd probably notice that by the fact that we stop calling it 'death' :) . DirkvdM 12:45, 6 October 2005 (UTC)

Evolution VS Intelligent Design[edit]

Is there links and/or information regarding which might be more valid AKA research?

--24.1.191.232 19:35, 4 October 2005 (UTC)

You might look at our article on evolution or evidence for evolution, both of which have links relating to this. In short form, mainstream biologists say they have far more reason to support naturalistic evolution than intelligent design, that all of the supposed ID evidence falls short, and furthermore would say that ID doesn't have any research program associated with it. ID supporters would claim that mainstream scientists have ruthlessly suppressed the truth of their work and are ideologically and methodologically opposed to their approach. Repeat many times over and that's pretty much the evolution v. ID debate in a nutshell. --Fastfission 20:03, 4 October 2005 (UTC)
Also, the mainstream would argue that ID is deeply philosophically flawed in that it does not follow established methods of science such as falsifiability, that there isn't any positive evidence for ID in existence, and that as a subject ID cannot be researched because key parts, like intelligence, design and complexity are left intentionally undefined.--Fangz 22:00, 4 October 2005 (UTC)
Mainstream 'science' argues a lot of things--WwJd 22:10, 4 October 2005 (UTC)
Mainstream scientists continually argue with each other. That's how it moves forward, modifying old models or replacing them with new models to fit the observations. In fact, to make your name in science the best thing to do is discover something so new and different that it brings into doubt previous dogma. RNA interference is a recent example. It seems that the ID 'scientists' are on the cusp of big news, i can't wait to here their discoveries. David D. (Talk) 23:29, 4 October 2005 (UTC)

birth rate[edit]

what is the birth rate in massachusetts?

If you do a Google search for "birth rate massachusetts", the first page that comes up is this press release from the state (sorry, Commonwealth...) government, discussing a report containing this information from 2003, and much, much more. This report, all eight chapters of it, is available here, as well as historical data from earlier such reports. Google (and the other search engines) are your friends...--Robert Merkel 00:44, 5 October 2005 (UTC)

particles are always in what[edit]

Please clarify your question. What, exactly, do you want to know? --Ashenai (talk) 22:30, 4 October 2005 (UTC)

Maybe it's a riddle...? -- SCZenz 00:47, 5 October 2005 (UTC)
constant motion?--Michael 04:28, 9 October 2005 (UTC)
a matrix of some sort? --66.82.9.62 04:12, 18 October 2005 (UTC)

Heroin in Food[edit]

I know this sounds crazy, but I NEED to know EVERYTHING that happens to the human body if you EAT heroin. I have even gone on sites in New Zealand and Australia trying to find the answer to this. I have found nothing anywhere! I want to know how it breaks down chemically, the amounts in blood versus stomach contents, morphine to 6MAM, how long it takes to die. I think you get it.Thank you for ANY answers you can give me. Toni I'm sorry!I did not mean to send this twice.Until my daughter died I,I wasn't even sure how to turn one on.

What exactly do you mean by the phrase "how long it takes to die?" That would probably mean disintegrate or dissolve or dissociate or discharge from the body when referring to heroin.--Screwball23 14:41, 17 October 2005 (UTC)

Search medline for heroin overdose like this [24]. You get hundreds of hits. You will have to sift for those that might describe oral overdose, like this PMID 10829332. Look at its bibliography for previously published articles on oral overdose. What you really want is something that describes the characteristic effects of oral OD vs injected OD because the latter is hundreds of times more common. Alternatively, go to a medical school library and ask for some toxicology and drug abuse texts. Look at the references to their chapters. I assume you are not dealing with an oral OD at this minute? If so, get him to the ER. alteripse 23:41, 4 October 2005 (UTC)

One warning - medical journals are written for doctors and scientists to communicate with each other, and consequently they assume a *lot* of background knowledge that doctors or biological scientists receive as part of their college training. It may take you some time and a fair bit of reading to familiarise yourself with the relevant background (though the Wikipedia is a reasonably good place to get a lot of that background), but it's by no means impossible. Many articles will also use some statistics, so you may need to learn a bit about that. Good luck, and I hope you find what you are looking for, whatever that is. --Robert Merkel 01:01, 5 October 2005 (UTC)
If you eat heroin, it will be absorbed either as heroin itself or as morphine (some heroin breaks down to morphine in the stomach). What happens depends on the dose and the individual. The opiates will be absorbed slower than if the were injected, but the total length of time that the patient is exposed will be longer. Physchim62 15:29, 7 October 2005 (UTC)

Would inducing vomiting be a good idea? --03:21, 13 October 2005 (UTC)

Itunes Problem[edit]

I have a bit of an interesting situation regarding iTunes. I am attempting to share my music so that a friend can access it. However, we seem to be on different subnets, despite the fact that we are using the same ethernet jack to access the internet. Would it make a difference that I intially installed and started intunes using a different ethernet jack across campus? The initial network setup was also done across campus, perhaps if I change my subnet this will solve the problem? Thanks for any suggestions!

How exactly are you using the "same" ethernet jack to access the internet? iTunes isn't designed to work via the internet anyway; rather, it's designed to work over local networks, so if you are both using the same router or something like that, things should be hunky-dory. Also, what are the models and capabilities of the computers you are using? Are they AirPort/802.11 capable? Garrett Albright 17:08, 5 October 2005 (UTC)

Poliosis / White Forelock[edit]

Hi This is not really a question but more of a request. I have performed some google searches to find a name for my husband's white tuft of hair above his forehead. I found Poliosis and White Forelock. I also found a list of dreadful diseases of which I'm fairly certain he has none. I then tried to find any information possible on Wikipedia and the search came up with zero. I'm just wondering if there are any personality traits (like extreme intelligence or other endowment) that might accompany this somewhat less common physical characteristic. I'd love it if anyone in-the-know could add this subject to your website.

thanks

There are many minor genetic physical traits that can occur by themselves or with several other physical anomalies. When they occur by themselves they have no hidden significance and cause no problems. When they occur with multiple other anomalies, some of those other problems can turn out to cause serious trouble. This combination of anomalies is usually referred to as a congenital syndrome. Other examples of minor physical anomalies that can be of no significance by themselves or can occur as part of a more serious syndrome are little pits in front of the ears, short broad thumbs or fingers, high-arched palate, and indented chest. Finally, there are no personality traits associated with this type of minor isolated anomaly because the only body part affected is that area of the scalp. alteripse 01:44, 5 October 2005 (UTC)

You can get a tuft of white hair by being scared shitless. Someone in my family once got that after she had fallen between railway tracks and had a train run over her. She was otherwise unharmed, but you can imagine her state of mind at the moment. But now I wonder how such a thing can happen. Does all the pigment get sucked out of the hair? And how does a scare cause that? DirkvdM 12:53, 6 October 2005 (UTC)

Having the pigment "sucked out" of hairs is as likely as having a sudden fright turn your nail polish from red to blue. Hairs already extruded from the hair follicles do not change color unless dyed, bleached, or oxidized. alteripse 03:16, 7 October 2005 (UTC)

I agree that the color of existing hair won't change due to stress, but having a localized loss of pigment in future hair due to a stressful episode isn't impossible. I don't know if any studies have been done on this, but I can easily imagine that stress hormones like adrenalin could interact with pigment cells and cause them to shut down. Other causes could be genetic or environmental, such as Sun-bleaching (which actually could destroy the pigment in existing hair). StuRat 06:32, 9 October 2005 (UTC)

math[edit]

If you know the exact date a person was born (year, month, and day) how can you quickly tell them what day of the week their birthday will fall on this year? With no help from a calender thanks.

See Calculating the day of the week.-gadfium 03:47, 5 October 2005 (UTC)

ABOUT BULLSEYE NETWORK VIRUS[edit]

When I use Internet Explorer, suddenly, a pop-up opens with the heading 'BULLSEYE NETWORK'. This pop-up appears when I open any website! Is that a virus that has attacked my computer or my Internet explorer? What should I do to get rid of that? Can anyone tell me more about this Virus?

You have aquired a piece of adware. This is not technically a virus, but is almost certainly software you don't want on your computer. It is designed to be difficult to remove. I recommend you get a copy of Ad-Aware or any of its competitors and run it on your computer. The following Symantec page may be useful to you: [25].
To prevent such infections in the future, please consider using a different browser, either Firefox or Opera. Internet Explorer is particularly prone to such infections.-gadfium 03:42, 5 October 2005 (UTC)
Or better still, switch to Linux. That should shield you a whole lot more against viruses and the like. DirkvdM 12:55, 6 October 2005 (UTC)

Linux Lover 69.181.206.232 04:21, 10 October 2005 (UTC)

Well, nothing wrong with that, is there? DirkvdM 18:16, 11 October 2005 (UTC)
If you switch to Linux, then there are still companies openly trying to abuse your computer for malicious reasons and not facing any consequences for it (even if it doesn't affect linux users much), so I suppose you could say it hasn't solved the problem. (and might even still be a problem if they find a vulnerability in some Free Software, or trick a linux user into installing their software). I'd take 69.181.206.232's comment as a compliment though... Ojw 18:35, 14 October 2005 (UTC)

maths[edit]

Try starting in Mathematics --Borbrav 04:05, 5 October 2005 (UTC)

Random vector member?[edit]

In the standard template library for C++, is there any trivial way to get a random member of a vector (or map) safely? - RedWordSmith 04:57, 5 October 2005 (UTC)

If I remember correctly (and I may not), isn't access to a random member of a vector O(1)? I believe vectors aren't linked list-backed types. Or is what you ask in the "safely" part? If so, what do you mean? Dysprosia 09:07, 5 October 2005 (UTC)
User:RedWordSmith wants to choose a random element and to access it with a single command. I don't think that is possible. Masatran 10:37, 5 October 2005 (UTC)
Yes, exactly. Any ideas on what the best way to do this using multiple commands? I've thought about shuffling the entire vector somehow a couple times and then taking an element from the top, but that can't be efficent no matter how it's done. - RedWordSmith 20:57, 5 October 2005 (UTC)
C++ vectors are random access, implying O(1) access, thus these are most likely not linked-list like types. What is wrong with using operator[] on the vector? Dysprosia 22:47, 5 October 2005 (UTC)


Maybe I'm missing something here, but wouldn't the following three step process work:
  1. Find out the number of elements l in the vector (my C++ is very rusty, but isn't that the length method of the vector class)?
  2. Generate a random number i, 0 \leq i < l with a pseudo-random number generator.
  3. Access the i'th object in the vector (either with operator[] or the at method, which is range-checked.
The choice of which pseudorandom number generator to use depends on your application. If, for some reason, it is important that an attacker not be able to predict which element will be selected next based on the elements selected previously, you need a cryptographically secure pseudo-random number generator, otherwise any modern generator, including the one in your system library, will probably do (though I prefer to use the Mersenne twister for all my own simulation work because it's both good and fast).
If you want a guarantee that you won't get repeated elements, then a shuffle is probably the best way to go. But here's a basic performance tip; if your objects are large, create a vector/array of pointers to them and shuffle the pointer array rather than the objects themselves.
As to the interface, surely you could define a subclass of vector which adds a "ranelement" method that implements the procedure I've described above? --Robert Merkel 01:00, 6 October 2005 (UTC)
OH. I get it now. Red wants to access an element at random. Yes, that solution is the one that first comes to mind. I don't think there's a simpler method... Dysprosia 09:31, 6 October 2005 (UTC)
Thanks, I'll give it a try. For some reason I was under the impression that the element choosen by the random number generator might not exist; I guess I'm just too used to plain C. I think I also got thrown off track reading about nonstandard methods to get random samples at one point. - RedWordSmith 00:06, 7 October 2005 (UTC)
Mod it with l if your RNG doesn't do generation within a certain range. Dysprosia 10:27, 7 October 2005 (UTC)

Anabolism and lifespan[edit]

Does a moderate level of body building and the associated muscle mass gain cause a decrease in life span? Lets assume that the person doing the body building and undergoing anabolism has a normal BMI and average build (that is, they are not overweight or underweight). Also assume that there are no steroids or supplements involved - only a small increase in protein rich foods being consumed. 205.188.117.71 04:59, 5 October 2005 (UTC)

No evidence is available for your specific question because such changes are never done in isolation from other factors that might change lifespan: healthier eating (e.g., reduced fat intake), reduction of unhealthy exposures (e.g., less time with secondhand smoke), etc. There is some evidence that in small mammals those who are allowed to eat less calories daily over most of their lifespan live a bit longer; this appears to be a phenomenon distinct from simple avoidance of obesity but we have no way to extrapolate this to people or to know exactly what the mechanism is. This topic of changing life span by changing daily living habits or eating habits is generally referred to as life extension and much has been published online and in the scientific literature but the quality ranges widely and much of what has been written about people is speculation, opinion, or marketing written to sell a product. Be skeptical. alteripse 10:36, 5 October 2005 (UTC)

The trick to a long life is to metabolize slowly. Like my turtle which I expect to out live me by about 100 years. I metabolize quickly because I like to have fun...unlike my turtle who just sits in the sun all day.--Eye 20:13, 5 October 2005 (UTC)

Graying Hair[edit]

Why does hair turn gray or white as humans age?

  • Our Hair article states: "Older people tend to develop gray hair (actually colorless) because the pigmentation in the hair gets lost and the hair becomes colorless. The age at which this occurs varies from person to person, but in general nearly everyone 75 years or older has gray hair, and in general men tend to become gray at younger ages than women." Capitalistroadster 07:19, 5 October 2005 (UTC)
    • This answer is perilously close to Moliere's explanation that a sleeping potion worked "because of its dormitive properties." I am not sure how clearly we understand the process by which hair follicles stop having pigment. Is pigment generated by intracellular processes that are programmed to stop at a certain age? Are there separate cells at the base of hair follicles that add the pigment to a growing hair? What is the difference between hair follicle cells that grow a pigmented hair versus a non-pigmented hair? Are these hormone-dependent changes like puberty or menopause-- if so we have surprisingly little understanding of this type of change in early or middle adult life. Are these specific genetic responses to a certain duration and level of hormone exposure, like male pattern baldness? Interesting question. Anyone want to research an article on hair color? alteripse 10:52, 5 October 2005 (UTC) Well, guess what, the answer was already in our article:
The change in hair color is caused by the gradual decrease of pigmentation that occurs when melanin ceases to be produced in the hair root, and new hairs grow in without pigment. Two genes appear to be responsible for the process of greying, Bcl2 and Mitf. The stem cells at the base of hair follicles are responsible for producing melanocytes, the cells that produce and store pigment in hair and skin. The death of the melanocyte stem cells cause hair to begin going grey. (Nishimura, et al., 2005)

Perhaps you didn't mean to get into the technical details of how pigmentation stops being produced, but were rather asking why, what evolutionary purpose does gray and white hair serve ? It may be that it serves no purpose, and is just a malfunction that isn't very harmful, so isn't selected very strongly againt. Another possibility is that visual age markers, like gray hair and wrinkles, are in some way helpful to the species. On the positive side, they may be ways to identify older people, who presumably have valuable knowledge and experience to offer, which may help the group survive. A more negative interpretation may be that this helps to identify people who are beyond their ideal fertility age, and thus should be avoided for younger more fertile mates. If either of these is a benefit to marking older people with gray and white hair, then evolution may actually select for this feature. Note that many other mammals share this trait with humans. StuRat 06:20, 9 October 2005 (UTC)

thrust agumentation[edit]

why a water nozzle is having a greater reaction when it is faced by a rigid wall very close to it rather than when it is faced in free air. --202.137.218.75 07:51, 5 October 2005 (UTC)Abhishek gupta, India
(formatted question and removed email - Mgm|(talk) 09:52, 5 October 2005 (UTC))

Newton's third law? Dysprosia 10:30, 5 October 2005 (UTC)
You didn't say if the wall was right up against it or just close. When the nozzle is pressed right up against the wall the water can't get out as easily and allows the pressure to build up. This is also why a nozzle causes greater reaction, than when water comes straight out the end of the hose.
Dysprosia is correct. When in the open air, the water pushes air out of the way, as the air can freely compress and move. As you approach the wall (which presumably does not compress or move), the water exerts a force on the wall, and the wall effects a reciprocal force on the water. At distance, the water tends to splatter into the air (per the initial condition). As the nozzle gets closer, more of the wall→water force is directed back toward the hose. Since water isn't compressible, this force transmits into the hose collectively. When the nozzle is directly adjacent to the wall, virtually all of the force affects the hose. — Lomn | Talk / RfC 14:36, 5 October 2005 (UTC)

Stabilizing the frequency of vibrations in a quartz crystal used in an oscillator circuit[edit]

Dear Wikipedia Volunteer, I am currently undertaking a research project. For this to be successful, it is important for me to know how to stabilize the frequency of vibrations of the quartz crystal used in an oscillator circuit. The quartz crystal in question is a 14.3183 MHz oscillator, but the output frequency is accurate only till 14.31 MHz (i.e. about 10 kHz). How can I stabilize the vibrations so as to get accurate output frequency in the order of tens of Hz? I would be highly obliged if you kindly post the answer to my query at your earliest convenience, or give me a few references in this regard. Thanking you, Yours sincerely, Saikat Das (removed e-mail address)

Saikat, I don't know the details of your project, but if the crucial thing is that you need a high-precision clock signal, would something like [these] do the job? I found this by googling "precision oscillator"; lots of other relevant links turned up. --Robert Merkel 15:18, 5 October 2005 (UTC)

OpenDocument XML editor wanted[edit]

Is there any OpenDocument editor that can edit the XML elements directly? —Masatran 11:10, 5 October 2005 (UTC)

If I'm not mistaken you can do that with any simple editor. At least that's the way to do it with html. Or do I misunderstand your question? DirkvdM 13:01, 6 October 2005 (UTC)
List of text editors and XML#XML Editors. The problem is, that I don't think OpenOffice, KWord, etc. like to edit OGW as a set of textfiles, they prefer to interpret it. Ojw 13:41, 9 October 2005 (UTC)

Dance Pads Sales[edit]

Hello dear friends, Does anybody know how many dance pads (in units) are sold annually in the USA by manufacturer? Thank you Sincerely

Are you referring to Dance Dance Revolution pads? -Haon 00:02, 11 October 2005 (UTC)

Individual Generators and natural disasters[edit]

how long do individual generators last? Can generators communications be affected in natural disasters? should we be investing in new research to develop cheaper and better generators? Is the Department of Homeland Security in the US preparing for wide scale, long term power outages?

  • Generators are more fuel-dependant than breakdown-prone, though such breakdowns can occur. On the whole, it depends entirely on the stockpiled fuel supply.
  • I have no idea what generator communications are. Could you elaborate?
  • Probably not. Again, fuel source is the main concern (and I'd consider a cold fusion generator more a problem of cold fusion research than generator research)
  • I don't think there's any way the U.S. at large can prepare for wide scale long term loss of power. Check out some apocalyptic fiction (Alas, Babylon and Lucifer's Hammer are good examples) for thoughts on what such widespread devastation would mean for modern first-world society. In a nutshell, if a disaster of such magnitude strikes, basic survival will be far more important than maintaining the power grid. That said, reducing the dependancy on imported oil would alleviate a major choke point for the fuel supply. Nuclear energy (the most modular major power source) has been overwhelmingly unpopular since Three Mile Island and Chernobyl, however. — Lomn | Talk / RfC 14:27, 5 October 2005 (UTC)
Generators will last as long as there is fuel for them and they stay in good working order. I presume you mean emergency type generators like you might find in the hardware store. There is ongoing research to find new ways to produce power (like fusion or solar power) but my opinion is the generators we have are just about as good as they can be expected to get without a technological advance.
As far as your question about whether "Homeland Security" is prepared for anything except re-electing republicans, I think we got a pretty clear answer last month. alteripse 15:08, 5 October 2005 (UTC)
To quote someone or other - "There is a major disjoint between people who think national security means keeping the nation safe, and those who think it means blowing shit up." Shimgray | talk | 20:04, 5 October 2005 (UTC)

Photosynthesis[edit]

Give an example of an experiment to find if photosynthesis has taken place inside a leaf.

Please answer this question now beacause I have a test and I could not understand this question. Thank you

You could read photosynthesis, but we're not really in the business of doing other peoples' homework here. -- SCZenz 16:13, 5 October 2005 (UTC)
I'm feeling nice, so I'll give you a hint.... What is a product of photosynthesis that you can test for? -(Fang)
You mean like electrons? David D. (Talk) 22:23, 5 October 2005 (UTC)
Electrons are not a product of photosynthesis. Imagine photosynthesis as an equation. What does photosynthesis produce? --Fastfission 17:00, 6 October 2005 (UTC)
2H20 + light (4 photons) --> O2 + 4H+ + 4e- is the first step of photosynthesis. Also known as the light reactions. I was trying to give a clue, although I admit it was somewhat cryptic. The traditional equation for photosynthesis ( 6CO2 + 6H20 + light --> 3O2 + glucose) is very misleading since it does not recognise that there are several independent reaction associated with carbon fixation. The first step does not involve the fixation of carbon it is all about converting light energy into chemical energy. The reduction of NADP to NADPH using the reducing potential of the electrons. As well as ATP from the movment of the electrons through the electron transport chain in the thylakoid membrane. David D. (Talk) 17:25, 6 October 2005 (UTC)

Heroin[edit]

What happened to my ? on heroin when eaten in food? Thanks, Toni

We answered it. Read more closely above. alteripse 15:06, 5 October 2005 (UTC)

Internet Statistics[edit]

I am attempting to find some internet statistics:

  1. How many people currently use Windows 98 vs. Windows XP?
  2. How many people have dial-up vs. broadband?
  3. How many people have an 800 X 600 monitor vs. 1024 X 768 or larger?


Thanks,
<removed e-mail address>

  • I'm not sure about the numbers, but if you want to know this because of some design job, I recommend you design with the Windows 98 dial-up 800x600 users in mind (at the very keast offer a low-bandwidth option for them). There's nothing more annoying than site, images or programs that are not designed for your system. - Mgm|(talk) 20:57, 5 October 2005 (UTC)

w3 publishes this info here: http://www.w3schools.com/browsers/browsers_stats.asp Boneyard 12:31, 11 October 2005 (UTC)

different question[edit]

If you buy stock in companies that sell this stuff, then you get their annual reports which have actual numbers of how many got sold that year. Some companies make their annual reports available to non-shareholders. So then you need to get them for every year since the products that interest you came out.
There are also places that have already done this kind of research and published the results, Gartner Research for example ... use Google or some other search engine (there are scores if not hundreds to choose from) to find places that do Research, then search them for the kind of research reports you interested in ... I think Gartner Magic Squares would be very close to what you looking for.
Gartner Magic Squares are charts of various types of products within some industry ... one dimension is all the stuff the products can do, another dimension is degree of market share the market leaders have, yet another thing shown is how good the stuff is relative to each other, with various vendors products plotted on this thing, accompanied by an article that goes into details about what is plotted on the graph.

AlMac|(talk) 15:27, 8 October 2005 (UTC)

How do plants and trees live in islands where their roots are in sea water?[edit]

Hello everybody,


I have always been wondering while seeing some nature tv programs or photos or etc that how come trees are able to live in such conditions as in islands where the soil is ssandy and permeable to sea water and these trees most probably have roots that are soaked in salty sea water. Apart from the fact that many trees, as far as I know, could not stand the salt in the sea water, their roots are also not able to breath oxygen, could they? As you see in many commersial photos or educational tv products there are islands where their jungles are only a few meters away from the sea water. How is that?

So please let me know how do these plants survive? Is their roots in sea water at all? It those are those roots adapted to these situations or their is some mgical thing happening there?

I hope i could have been able to explain my question as good as possible.

Thank you for your replies in advance.

Eqbal Vakilzadeh

Plants, like other forms of life, are adapted to fit certian circumstances. Not all trees are the same.
It is not just about adaptations. Obviously mangroves do live in brackish water. They have several adaptations to allow this. High quantities of salt in their cells that means water can move from the brackish water to the even saltier mangrove cells by osmosis. This would not be possible for regular trees as you suggest above. mangroves also have air tubes in their roots specifically to get the oxygen down to the tissues under water. You're right that hypoxia this is a very real problem for trees that live in standing water.
With respect to the islands, the key is that the ground water can push out the sea water. This web site has a diagram and description [26]. Even trees at the edge of the island it is possible for them to get fresh water. David D. (Talk) 21:41, 5 October 2005 (UTC)

This is it. thanks for the info and the link. eqbal

Computing[edit]

differences between windows nt and windows 98

Apart from the fact that they're both versions of Windows from Microsoft, nearly everything. The code bases and design rationales are entirely different, and that filters through the whole of both operating systems. Check out Windows NT and Windows 98 for more. — Lomn | Talk / RfC 18:04, 5 October 2005 (UTC)

manufacture of dimensions in nanometer range[edit]

How is the stylus tip made up of hard material like diamond which is used in surface roughness measurements manufactured to have a radius in the range of nanometers ?What is the procedure involved?

                --------------------------------------------------------------------

Aggregated diamond nanorods have been made by a new method and there are more conventional methods such as Chemical vapor deposition. --JWSchmidt 03:22, 8 October 2005 (UTC)

Unknown Energy?[edit]

Would it be right to say that energy in its pure form is unknown to us? For instance I cannot see the light that passes across my field of view. It seems that we can touch, hear, and see energy but only when it is interacting with the matter of our own bodies, our eyes, hears, or skin and in doing so does the energy that triggers the reaction of our senses changes it form? If so would it not also be so that what ever device we construct to measure energy would have the effect of changing the energy which we try to measure? Could or does energy exist in a form unknown out side the world of matter that we exist in? --Eye 19:57, 5 October 2005 (UTC)

Energy is a conserved quantity that is associated with location (potential energy), motion (kinetic energy), and with matter itself (see E=mc²). Possibly the best candidate for "pure energy" would be the photon, the massless light particle, and you are absolutely right that one only sees photons when they interact with the matter in your eyes (or, if they hit your skin, they can give you a sunburn). It is a principle of quantum mechanics that you cannot observe anything without changing it; this applies to energy in any form, regardless of the device you build. To answer your last question, dark matter and dark energy are two things whose affects we can observe in cosmology but whose nature remains unknown to us; they compose the vast majority of the energy of the universe. Hope that helps! -- SCZenz 20:09, 5 October 2005 (UTC)

Mmm...I like the dark energy bit.--Eye 22:06, 5 October 2005 (UTC)

Better known as the Measurement problem. - Cobra Ky Flag of the United States.svg (talk, contribs) 22:15, 5 October 2005 (UTC)
Anything that exists outside the reality we live in can not be observed by us and therefore does not exist as far as we can (ever) tell. Dark matter and energy are theoretical solutions to problems in cosmology. One could say that they are observed indirectly, but then everything is observed indirectly. When I look at a table I really just register the light that is reflected by it. And I don't even see the light, but only register the effect it has in my eyes and brains. DirkvdM 13:54, 6 October 2005 (UTC)
  1. Would it be right to say that energy in its pure form is unknown to us? No, that is not right. Energy is very well understood in physics.
  2. For instance I cannot see the light that passes across my field of view. You see light that interacts with your eyes. You don't see light that is not interacting with you. Same for sounds, pressure (touch) and so forth.
  3. [D]oes the energy that triggers the reaction of our senses change its form? Yes.
  4. If so would it not also be so that what ever device we construct to measure energy would have the effect of changing the energy which we try to measure? Yes.
  5. Could or does energy exist in a form unknown out side the world of matter that we exist in? No. Matter is energy. Energy is matter. Forms change. WAS 4.250 21:33, 10 October 2005 (UTC)

water solubiliry in the body with homeostasis[edit]

How is water solubility used to maintain homeostasis in the body? What are four examples of this?

It all depends on what points your lecturer made. Was there reding material set with this problem. it might be worth checking that first.David D. (Talk) 22:41, 5 October 2005 (UTC)

Freshwater Invertebrates and Marine Invertebrates[edit]

I am trying to find the basic information on what differentiates certain freshwater invertebrates with marine invertebrates. For example, there are several invertebrates (Crayfish, Jellyfish, snails, etc.) that live in either freshwater or marine/sea water, what differentiates them? Why can one species of crayfish live only in freshwater and not in saltwater? How is the freshwater crayfish different from the marine crayfish?

If anyone can help me to answer this, I would REALLY appreciate it! Thanks!

  • Our Crayfish article states that in New Zealand "the name crayfish or cray, refers to a spiny lobster, and crayfish are called freshwater crays or koura, the Maori name for the animal." Is that what you are referring to?

Alternatively, I suspect that the Speciation article referring to the emergence of new species through Evolution and Natural Selection. Capitalistroadster 01:17, 6 October 2005 (UTC)

The basic difference is physiological. The freshwater organisms are better at pumping excess water out of their bodies, thus maintaining the salinity of their cells, coelomic fluid or blood. WormRunner | Talk 02:57, 6 October 2005 (UTC)

DNA/Cloning[edit]

How much of a DNA sample is enough to make a clone of something? What is the best source of DNA in relation to cloning?

No one has successfully made a cloned animal with just a DNA sample to start with. alteripse 00:56, 6 October 2005 (UTC)

To make an actual clone of something, you'd need to replicate all of its DNA (or extract a full set). A full set of the DNA of any living thing is present in every one of its cells. You could also read Genetics, DNA, and Cloning --Borbrav 01:20, 6 October 2005 (UTC)

In addition to the DNA you need the right environment, starting with the right cell (although I believe you don't necessarily need a cell of that specific species - something closely related would do). And then that cell needs a womb (natural or artificial) to grow in. DirkvdM 13:58, 6 October 2005 (UTC)

And you might want to try the article on Polymerase chain reaction to answer your "amount" question. --Michael 04:03, 10 October 2005 (UTC)

Cloning is typically done with an easily obtained cell, like a skin cell, or in the case of Dolly, this first cloned sheep, an udder cell. Cloning usually takes hundreds of tries, using one cell per try.

Computer languages[edit]

what is an atom in some computer languages?

Take a look at Lisp atom, and also Prolog. There may be other meanings of the term in other programming languages.-gadfium 02:54, 6 October 2005 (UTC)

Killing Me Softfruit : Which food would kill you first?[edit]

Of all the things a person in a modern Western democracy might normally consume as part of a meal, which would kill with the lowest dosage? The test subject is to be fed on the test food alone and is allowed any quantity of water and time for comfort breaks. --bodnotbod 01:46, 6 October 2005 (UTC)

My guess would be alcohol. — Laura Scudder | Talk 01:54, 6 October 2005 (UTC)

Oooh, fun game. Tricky though. For instance if you include trace amounts of things that we ingest but don't intend to and are not conscious of, the answer would be aflatoxins, other natural neurotoxins like botulinum toxin, or pesticides and other chemical contaminants. We certainly "might normally consume as part of a meal" trace amounts of these things, but it would take only mg amounts to kill us.

Now if you restrict your contest to things that we deliberately and knowingly ingest as food, then alcohol seems a pretty good choice if taken as a single dose (1-3 oz of pure ethanol can be fatal to an adult), but if spaced out it would require a much larger amount. Same for caffeine. However, your allowance for "any quantity of ... time for comfort breaks" would suggest we could stretch out the exposure. So it looks like you'd better impose more rules. alteripse 03:08, 6 October 2005 (UTC)

  • I wonder if you could kill yourself by OD'ing on salt? --jpgordon∇∆∇∆ 03:59, 6 October 2005 (UTC)

Of course. You can OD on water or oxygen also. The amount of salt that would kill you if you had access to sufficient water and could take "comfort breaks" to unload some of it would be larger than the mg of caffeine that would be fatal. However it is not a bad suggestion if the contest limited you to a single dose you had to ingest in one sitting. alteripse 04:07, 6 October 2005 (UTC)

Well, a relatively small bite of most anything that can be lodged in the throat has taken down multitudes over the ages but I think I am cheating. Qaz (talk) 04:14, 6 October 2005 (UTC)

If you knew you had a food allergy- you could do it will a minimal amount of the relavant food stuff.--nixie 04:19, 6 October 2005 (UTC)

Vinegar wouldn't do you too much good either under the test conditions. Salt would fairly quickly cause renal failure (or drowning, by the amount of water consumed - this has happened in France). Cooking oil might start dehydration by diarrhea, but probably wouldn't work as fast as the others. Anything infected with cholera would be pretty fatal, as would certain uncooked beans, but that must certainly be cheating! Physchim62 15:41, 7 October 2005 (UTC)
Most of these seem rather unappetising. Except maybe the alcohol. How about a couple of pounds of green potatoes, nicely cooked in the means of your choice? Notinasnaid 17:41, 7 October 2005 (UTC)
That's almost cheating, too, as you wouldn't normally eat it. Along similar lines I could propose what killed Christopher McCandless: potato seeds which he helpfully discovered become poisonous in August. But so far I think alcohol is the best bet so far as things you'd normally ingest and could get someone to down fast enough. — Laura Scudder | Talk 17:55, 7 October 2005 (UTC)
Could you add some detail about how Christopher McCandless died to that article? Superm401 | Talk 22:18, 15 October 2005 (UTC)
A freshman died from water intoxication recently during a hazing incident at California State University, Chico. User:Zoe|(talk) 07:45, 9 October 2005 (UTC)
  • Some interesting answers, but I was tending to think of food rather than drink, so alcohol would have been ruled out. I'd like an answer that doesn't involve taking out one of the ingredients / chemicals of a food and eating that in isolation unless you would normally eat it in isolation too. --bodnotbod 00:27, 13 October 2005 (UTC)

Are you planning to poison somebody?--Shanedidona 03:15, 13 October 2005 (UTC)

    • Er...no. No. What an idea! Ha ha, er... (Hides extremely large punnet of strawberries under desk). --bodnotbod 20:51, 17 October 2005 (UTC)

Neurotransmitter Receptor Unbinding[edit]

When neurotransmitters are released, they bind onto a receptor on the post-synaptic neuron, and open a ligand-gated channel. However, I can't find any details on how or if they 'unbind' so that this channel can reset, and the general mechanism of this occuring. Certainly, the pre-synaptic cell and enzymes have mechanisms to reduce the concentration of neurotransmitters in the cleft, but I don't see how this causes the neurotransmitter molecules to unbind and therefore allow the channel to be activated again. Any details on this mechanism or whether such a mechanism actually exists would be of great use. Thanks. --Lynto008 03:20, 6 October 2005 (UTC)

You are reminding my of the most boring part of by biomed courses :) I just whipped out my copy of Human Physiology (Vander, Sherman, and Lucino).
If memory serves, unbinding depends on the type of ion channel. [Ligands] "produce either an allosteric or covalent change in the shape of the channel protein. Such channels are termed "ligand-gated channels, and the ligands that influence them are often chemical messangers" (116). Those channels are often further subdivided. What turns the channels "off" depends on the type. It's often either the unbinding of the ligand, or a messanger lipid, or another enzyme ligand, 'etc. →Raul654 03:31, 6 October 2005 (UTC)

So when its said that the ligand 'binds' to the receptor, what is really meant is that it 'triggers' the receptor by changing it, rather than actually attaching? More like the ligand turns on a switch than acts like a key? Because the way that the article Neurotransmitters (and just about everything else i can find on the internet) puts it, "The neurotransmitters... bind to receptors.", which to me seems to imply that it attaches somehow and would remain on the channel triggering it until it is somehow cleaved off. I know that this seems a bit pedantic but to someone who is trying to grasp these concepts, it certainly makes a huge difference. Is it true that the ligands don't really 'bind' per se and that there is actually a distinction? If so, this needs to be mentioned somewhere in wikipedia. Thanks again. --Lynto008 07:50, 6 October 2005 (UTC)

What you are asking is really not biology, but more physical chemistry ;)
A ligand is, by defintion, something that chemically binds to something else. Neurotransmitters are ligands that bind *VERY WEAKLY* to receptors (ion-gated channels), meaning it takes very little energy to break such bonds. The process of binding causes the channel to change shape, allowing stuff to pass through it. However, the weak bonding means that it's very easy for the ligand to pop right back off - possibly even caused by thermal energy (remember, everything is vibrating very fast at the molecular level due to heat -- imagine trying to hold onto something slippery in the middle of an earthquake). →Raul654 08:00, 6 October 2005 (UTC)

Nevermind - I looked up allosteric. Means binding. Duh. --203.206.109.81 07:58, 6 October 2005 (UTC)

Technological trends in information systems[edit]

What are the key tehcnological trends that heighten ethical concerns?

I am taking "heighten ethical concerns" to mean "increase people's attention to the ethical aspects of their choice of behaviors." The key technological trends that allowed people to be aware of choices of behavior and to have the time energy and tools to think about ethics were were agriculture, hunting tools, food storage technology, and communication and recording technologies. If you mean something else by the phrase "heighten ethical concerns" please explain. alteripse 03:15, 6 October 2005 (UTC)

You might also educate yourself about the US law commonly called Sarbanes Oxley which imposed accountability standards on a wide spectrum of corporate and other entities doing business in the USA, in the wake of the accounting scandals that led to some of the largest companies in the world going bankrupt. These new regulations also imposed new rules on the information technology aspects of those companies, non-profits, unions, etc. that some people label as being ethical standards, and others label as additional money making sources for the lawyers, in a nation that is by the lawyers, for the lawyers and of the lawyers, with all the other residents being to provide the income to the lawyers. AlMac|(talk) 04:59, 8 October 2005 (UTC)

longest ship in the world?[edit]

The best I can find is an entry in the middle of this section: A.P._Moller-Maersk_Group#1993_-_1999_:_bigger_and_bigger. -- SCZenz 03:39, 6 October 2005 (UTC)

Unless the QMII's length is severely rounded, the transport ship I linked to has it by 1.9 m. -- SCZenz 03:58, 6 October 2005 (UTC)
Just a bit of trivia; the Great Eastern was built a century and a half before that but was almost 2/3 the size of these ships. Truly humungous for that time. DirkvdM 14:28, 6 October 2005 (UTC)

Queen Mary II is the longest cruise liner at 345 m LOA; Sovereign Mærsk is perhaps the longest container ship 346.9 m. But a number of supertankers are much bigger, for example, Knock Nevis, 458 m. Gdr 20:25, 6 October 2005 (UTC)

  • Though it barely counts as a ship -- more like a storage facility these days! The article does a good job of describing Knock Nevis and its twisted history. --jpgordon∇∆∇∆ 21:54, 6 October 2005 (UTC)

Uranium 238 decay chain[edit]

Is the information listed in http://en.wikipedia.org/wiki/Decay_chain correct?

Should Uranium 238 decay into an alpha particle, Thorium 234 AND two electrons?

Giving off an alpha particle, plus two electrons, would change reduce the number of nucleons by four and leave the charge unchanged. This would result in U-234, as the page says. So it's at least self-consistent. The decay you indicate has a charge imbalance, unless I misunderstand. -- SCZenz 03:56, 6 October 2005 (UTC)
The alpha particle is a helium nucleus, which has two protons and two neutrons in it. Thus, the U-238 loses two protons, two electrons, and two neutrons, and so charge is balanced. --Borbrav 00:32, 7 October 2005 (UTC)
Yes and no. The nuclear decay of U-238 is by loss of an alpha particle to give 234Th2−: the thorium nucleus is not sufficiently close to hold on to the two electrons it has inherited and these are lost to the environment. See also electron affinity. Physchim62 15:47, 7 October 2005 (UTC)

Atoms and molecules[edit]

Sun & planet gear & epicyclic gearing[edit]

Does anyone know the connections between the sun and planet gear and epicyclic gearing. I don't know whether the later is a 'new' name for the former or developed from it or if they are unrelated but share some terminology? Any help would be much appreciated. AllanHainey 07:52, 6 October 2005 (UTC)

The original sun-and-planet gear setup involved only two gears, as stated at that article. What I've read (I don't remember where) is that it was invented for the specific reason that the invention of the steam engine had created a need to convert reciprocating to rotary power, and someone else had already patented the simpler approach of using a crank for that purpose. This would suggest that the more general epicyclic-gearing arrangements shown in that article were developed independently, for applications where this actually was the best form of gearing; but I don't actually know. --Anonymous, 01:30 UTC, October 12, 2005

Rules of significant figures involving addition.[edit]

The rule for rounding to significant figures for addition is to round to the least number of decimal places involved. However, if the example were 1.01 + 3. + 1.1 would the rounding go to 4 or to 4.1? AKA, does a figure with no decimals mean to round to no decimals, or is it the least after that?

This came up in class yesterday and I was just wondering what the specific rule for this was and any reasoning behind this. Thanks.

That would depend wether that specific number with no decimals is an exact number or not. For example, if my journey from home to school took 1.75 km then I would travel 2 * 1.75 = 3.50 km from home to school and back. If I have a yard of 2m by 3.71m the total surface area would be 2 * 3.71 = 12m7m2. --R.Koot 14:26, 6 October 2005 (UTC)
Ah, trick question! 1.01 + 3. + 1.1 = 5.11 (not 4.whatever). As to how that should be rounded off, I'm a bit rusty, but I assume that the fact that there is a dot behind the 3 means that it's not exactly 3, but you don't have the numbers behind the dot, so you can't use those of the other numbers, so the answer is 4. (with a dot). As to whether that should be rounded off before or after the calculation, I forgot, but in this case the answers are the same. DirkvdM 14:40, 6 October 2005 (UTC)
Rounding for numbers of known higher precision should be done after calculations so as not to propagate rounding errors. Think of adding 2.7 4.6 2.55 and 3. Rounding before the addition causes the rounding errors to add getting the erroneus answer of 14, when it should be 13. It's a bigger deal with multiplication of course. - Taxman Talk 14:27, 7 October 2005 (UTC)
And R.Koot should go get his tuition fees back. 2 * 3.71 = 12m ? And I'm not referring to the omission of the '²'. DirkvdM 14:40, 6 October 2005 (UTC)
Uhhh... I don't even know what I meant there? --R.Koot 23:21, 6 October 2005 (UTC)
Thanks, Dirk. THat answered my question.... And nice catch on the 3 + 1 + 1 = 5... Oops!
Whenever you add, you keep all and only the decimals which were known in all of the numbers you were adding. i.e. 2.45+3.891=6.34, not 6.341. --Borbrav 00:22, 7 October 2005 (UTC)
Rounding rules have different schools of thought based on the context of what is being arithmeticed.
Suppose the military needs to move a certain volume of men and equipment, and the math comes out that to do this, they need 11.2 army trucks, the answer is not 11 trucks but 12, because there are cases where you always round up. AlMac|(talk) 05:02, 8 October 2005 (UTC)

English name of pen&paper game[edit]

The game is popular among Russian students. The rules are described here. "Pests" is a code-name. It's called "клопы" (a kind of pest) or "тараканы" (roaches) in Russian. I hope someone knows how it's called in English.  Grue  13:38, 6 October 2005 (UTC)

The rules sound conceptually similar to several other games I am familiar with:
  • The game of GO, which is an oriental guerrilla game sometimes considered to be the mental equivalent of CHESS, and several played on same kind of grid, with race to get some number in a row.
  • The game of LIFE which can be played solitaire, or in competition. There are variations on the game of LIFE, such as VIRUS, in which you design simple algorithms for growth of your PESTs to try to eat away at the enemy LIFE. I think some nuts have taken that interest into the design of computer viruses.
  • Then there are a number of ECOLOGY games played using different colored multi-sided dice (more than 6 sides) where the number on top represents the population of that animal or plant, which eats adjacent as food, leading to an increase in the population, but if there is not enough food, the population decreases.

AlMac|(talk) 18:39, 15 October 2005 (UTC)

This game "Pests" seems similar to (but not the same as) the game Conquest, which is a common video game in my area. -Juuitchan
So it seems there's no English equivalent. That's quite strange because I remember playing it in school in Perm about 8 years ago, and I've seen it played last week in Moscow. So it must be quite widespread. The game's quite interesting, and the rules are quite simple. I wonder why there isn't anything similar.  Grue  16:56, 17 October 2005 (UTC)

depersonalization[edit]

What is the original reference for the information contained on your website concerning depersonalization, particularly the information regarding suicide ( as well as the general information provided). I have seen this exact wording on several other websites, but no references for the information.

Thank you,

Donna McCleary

  • You can contact the people who contributed to the article, each of them is listed in the article's edit history. The links in the article appear to be authorative on the subject, so you might want to visit those and ask the people there for reliable references too. - Mgm|(talk) 15:50, 6 October 2005 (UTC)

helium[edit]

where did the name helium come from?

  • From Helium#History: "He and English chemist Edward Frankland named the element after the Greek word for the Sun god, Helios, and, assuming it was a metal, gave it an -ium ending (a mistake that was never corrected)." - Mgm|(talk) 15:52, 6 October 2005 (UTC)
  • If I remember rightly it was named after the sun because it was discovered after observing the spectrum of the sun's light during an eclipse.--stib 03:31, 13 October 2005 (UTC)

Heroin In Food[edit]

Until this AM I could not understand why I am having so many problems with my? Now I do.The reason I was asking about info. on ingesting heroin in food,is because that is how our daughter,Shenel,was murdered.People do not eat heroin,so we can find no info.on Toxicological Findings.That is ALL this is about!The FACTS!Any & all we can possibly get.As far as I know,and I have researched alot of drug sites,nobody knows.We did find alot of very good info.here,so I thought maybe you could find the answer to our ?.I just wish you would of let me know there was a problem with our ? instead of just deleting it.We'd still appreciate an answer,if you can find one.Our hearts are broken and she left behind two children.Eric was 4 , and Alyssa was 5 weeks old.Someday,if we can,we want to be able to explain all of this to Eric.Alyssa is with the man who killed her mother,so we lost her too.The sites we have gone on in New Zeland and Australia,which have done alot of studies on heroin,have made us realize the U.S.has alot to learn.Because of their lack of knowledge,this man got away with murder.It happens more often than you would ever believe,and we are all paying the price.We would be so grateful if you can help us?If not, I will know when I come back and see I have once again been deleted.I do want to thank you for all the good info.you did provide us with and say good-bye for now. Toni

Toni, I sympathise with your situation, talk about stressful. No one has deleted your questions. Your first post with replies is still here, but you need to scroll up a long way to find it. Likewise your second post is still present. Realise that new topics are being added to this pages rapidly. David D. (Talk) 18:28, 6 October 2005 (UTC)

Regarding Heads[edit]

There was some talk around here a few days ago regarding the possibility of head transplants. The general consensus seems to be that there is no real reason a head could not be transplanted onto a donor body and live, albeit as a quadriplegic. So the question that occurs to me is this: Is the classic sci-fi/horror staple of a severed head being kept alive, artifically, possible? What about the even more cliched "brain in a jar"? With an oxygenated/nutrient enriched blood supply, under strictly controlled hospital conditions, is there any reason why a human head could not be kept alive, other than ethical ones? Brian Schlosser42 18:32, 6 October 2005 (UTC)

Should be fine in theory.

But very difficult in practice. Certainly well beyond the current state of the art. See the Wikipedia articles on head transplants and whole-body transplants. Gdr 20:00, 6 October 2005 (UTC)

I'm not sure it would be that difficult in practice, certainly a non-trivial proposition, but given the success of primate head transplants, I would think that simply keeping a human (I presume that the questioner is talking about humans) head alive would be well within the current state of the art. The major obstacles to actually doing this would be ethical, not medical.
Funny that only a brain transplant is also called a whole body transplant. The same could be said for a head transplant I'd say. Also funny that the article on the former nevertheless goes on to speak about tranplanting the brain to another body. The alternative name exists for a reason (if one assumes personality resides in the brain). DirkvdM 20:40, 6 October 2005 (UTC)

The success of Dr. White's head transplants is, I think, rather overstated by our article. In the best cases, the head survived for several hours and showed signs of consciousness. Gdr 20:45, 6 October 2005 (UTC)

word password recovery[edit]

There is a free or open source word password recovery program, but I have lost it - does anyone know it? Thanks!

One program that is free for 30 days is Elcomsoft Advanced Office Password Recovery. I haven't tried it so I can't vouch for it, but it might get you out of immediate trouble. There are lots of other programs but this was the first I found which appears to have a fully functional demo available.-gadfium 03:05, 7 October 2005 (UTC)

Elements[edit]

What is the importance of Iron?

  • Reading Iron would be a good start. It's the final end-product of nuclear fusion, and steel is made from it. I think that's enough hints to start your essay! ;) -- SCZenz 21:38, 6 October 2005 (UTC)
  • Lets not give short shrift to its role in hemoglobin. There is also its role in that time... what was it called... oh yeah, it was the Iron Age. Qaz (talk) 06:25, 8 October 2005 (UTC)
  • Iron is one of the few metals we know of affected by magnetic fields. Rob Church Talk | FAD 15:49, 9 October 2005 (UTC)
  • If you don't use it your clothes end up wrinkled. DJ Clayworth 17:58, 7 October 2005 (UTC)
    • Unless you have decent clothes that don't wrinkle. DirkvdM 09:32, 8 October 2005 (UTC)
      • Or use a tumble dryer, and get them out quickly enough afterwards. Certain clothes can be hung to allow the wrinkles to fall out too. Rob Church Talk | FAD 15:49, 9 October 2005 (UTC)
        • The problem with this approach is that the fallen wrinkles collect at the bottom of your closet. If you don't wear socks or slippers, the wrinkles can then be transferred to your skin. (Ironing avoids this problem; the high heat inactivates wrinkles, which can then be transferred back down the powerlines for safe permanent disposal by the electric company.) TenOfAllTrades(talk) 16:10, 9 October 2005 (UTC)

Guys,guys, come on it's a serious question...without iron the wheels would fall off my truck...I wouldn't even have a truck...

Look at any skyline of a major city today.
Look at pictures of city skylines from 100 years ago.
Consider how it became possible to build them so much higher, thanks to modern development of metals and other building materials, and consider what they might look like 100 years from now ... will space elevators become commonplace?

AlMac|(talk) 09:09, 10 October 2005 (UTC)

Consider the importance of magnetism to the development of many modern conveniences, such as computers. AlMac|(talk) 09:10, 10 October 2005 (UTC)

Apparently this is another essay question (header added subsequently)[edit]

State two ways in which a singled-celled organism, such as an amoeba, and a human body cell are alike.

Any number of properties in cell might suffice, but my two favorites are:
  1. They're both smaller than a breadbox.
  2. Neither one, under most circumstances, contains very much uranium.
If I were you, I would write your essay based on something else, though. ;) -- SCZenz 22:22, 6 October 2005 (UTC)
See our article about eucariontes. --User:Mdob | Talk 20:43, 17 October 2005 (UTC)

Biology[edit]

Plants produce cholorophyll to capture the energy from the suns ray's and take in carbon dioxide from the air, and water from the soil. What characteristic of living things does the show?

Their tendency not to do their own homework. (LOL, great answer !)
In seriousness, you should ask a more specific question. That describes lots of characteristics of living things; I suspect that only one of them, however, is on your vocabulary list for the week. RSpeer 22:23, 6 October 2005 (UTC)
You might look at Life, in particular Life#A conventional definition. -- SCZenz 22:24, 6 October 2005 (UTC)

Adaptation?

Ears[edit]

What animals have ears on the sides of their body? ...rabbits on my bumper--Eye 20:28, 9 October 2005 (UTC) and What animals have ears on their antennae? ...flies on my windscreen--Eye 20:28, 9 October 2005 (UTC)

--24.214.167.141 22:57, 6 October 2005 (UTC) Should this be deleted?

Smelling Extract[edit]

I am battling a stopped up nose and I once heard that smelling peppermint extract could break up the mucus. Does this work? Would sniffing the extract fumes kill brain cells? Could it get me high?

Your brain cells are dying as we speak anyway, and I suspect wine would do more damage to them than peppermint. Why not try it and report back here?--inksT 04:47, 7 October 2005 (UTC)
I suggest you visit a pharmacy, sometimes called a drug store (that sells legal drugs) and direct your question to the pharmacist there. Typically there are scores of different brand names of remedies, at very reasonable prices. AlMac|(talk) 05:07, 8 October 2005 (UTC)

Cough drops create substantial vapors, that will serve such a purpose, while you suck on them. I suggest a menthol-eucalytptis blend, that really does the trick. StuRat 05:34, 9 October 2005 (UTC)

One up each nostril should work --Eye 20:25, 9 October 2005 (UTC)

how do telescopes work?[edit]

Optical telescopes use a series of lenses to magnify distant objects, the same way a microscope does. Other types of telescopes are a bit more compliated. →Raul654 04:23, 7 October 2005 (UTC)
  • Our Telescope article should be of some assistance as should the articles on specific types of telescope listed at the bottom of the telescope article. Capitalistroadster 05:01, 7 October 2005 (UTC)
  • Also, if you typed this query into google, your second hit would've been this page from HowStuffWorks.com which has some info which may help you if you find the Wikipedia article too difficult to understand. - Mgm|(talk) 16:31, 7 October 2005 (UTC)

Why do some noises cause goosebumps?[edit]

When someone scrapes their fingernails against a chalkboard, I get goosebumps. What is the reason in this?

I'm not sure exactly why sound initiates goosebumps, but the reaction is vestigial. Back when humans had hair covering their bodies, the reaction which is technically called piloerection, was intended to make ourselves appear larger, much like a cat does today when they are frightened. My guess would be, that a scary sound also triggers this reaction (like for instance the roar of a lion). Hope that helps. - Cobra Ky Flag of the United States.svg (talk, contribs) 17:18, 7 October 2005 (UTC)

medical term[edit]

What is meant by 'osteophytic lipping'?

Rgds, --Ciesse 203 13:52, 7 October 2005 (UTC)

Osteophytes are small projections of new bone growth or thickening. Lipping is a description of an x ray appearance. We need more context to interpret this, or you can ask your doctor. alteripse 19:46, 7 October 2005 (UTC)

I can actually answer this. They are indeed bony projections, usually found on the outer edges of articular surfaces of joints. Occurs in people exposed to heavy loads (eg. slave labourers) and elderly. Yay! My BSc in Anatomy was useful for something! This calls for a party!.....--inksT 02:46, 8 October 2005 (UTC)

How do protons(+) not repel eachother...and....[edit]

how do electrons(-) not stick together with protons(+)??

For the first question, this is the strong interaction - it's effectively nonexistent at long distances, but over very small distances (like those inside an atomic nucleus) it's very powerfully attractive. This is more powerful than the electromagnetic force, so it holds them together. See atomic nucleus. Think of it this way - two positive poles of a magnet will strongly repel each other, but if you duct-tape them together they won't actually be able to break apart, because the tape is stronger than the magnetism.
For the second question, think of them as orbiting the nucleus very fast - they're falling toward the atom, yes, but satellites are also always pulled towards the earth by gravity, and they don't land on the surface. This isn't a very accurate description, but you might find it helps make sense of the problem. Shimgray | talk | 14:48, 7 October 2005 (UTC)
Two protons, with no neutrons present, actually do repel each other. The strong nuclear force only helps in a nucleus where neutrons are present also. By the way, these are great questions--they were central mysteries of physics for much of the early 20th century. -- SCZenz 15:35, 7 October 2005 (UTC)
Also, remember that an electron is not a thing (like a little ball), but more like a wave, or ring of evergy around the nucleus. It has to remain at a specific distance in order to orbit around the nucleus, determined by it's wavelength. --Mary
Electrons are most certainly NOT "ring[s] of [energy] around the nucleus". Rangek 14:52, 18 October 2005 (UTC)

A good question to ask is how do neutrons help keep protons together in cases where the absence of neutrons woudl cause the protons to repel each other? Next question is why are neutrons stable in the nucleus when protons are present, but decay into a hydrogen atom when alone?

Those are also good questions.
  1. The answer to the first is that the strong force between the proton and neutron is stronger than either the proton-proton or neutron-neutron force, and is enough to bind a proton to a neutron. So you can think of a nucleus as being more bound by the proton-neutron attraction than anything else (although the other interactions contribute too, they wouldn't be enough by themselves).
  2. The answer to the second, I think, has to do with energy. A free neutron has more energy than its decay producs (e.g. a proton, an electron, and an antineutrino). But for most nuclei containing a neutron, the energy is actually lower as things are now than it would be if the decay happened. (Because of nucleus stability/bond strength issues in question 1.) Thus a free neutron decays, whereas neutrons in nuclei don't. Interestingly, nuclei with too many neutrons will have lower energy if a decay happens, and there the neutrons do undergo beta decay.
Hope that helps! -- SCZenz 22:41, 7 October 2005 (UTC)

Protons DO repel each other, but in the nuceus of an atom that repulsion is overpowered by the more powerful yet shorter distance acting force called strong interaction. Electons DO stick to the nucleus (protons and neutrons) of an atom; they are just millions of times BIGGER than the nucleus (visualize cotton balls glued to BBs). At the particle level, heavier things are smaller and lighter things are bigger due to the wave nature of things. The electrons get as close to the nucleus as they can, and their wave nature describes a shape looking like a donut or a sphere or a set of teardrops or other shapes (these are called orbitals, altho nothing is really orbiting). Talk about electrons orbiting is a heuristic in that it is a useful model without being accurate. WAS 4.250 22:04, 10 October 2005 (UTC)

Protons and electrons can "stick together". See electron capture. Rangek 14:57, 18 October 2005 (UTC)

Perl or Python?[edit]

I'm a budding computer programmer with free time on my hands. Is it better (more useful / more marketable in the job market) to learn Perl or Python? Or something else? I currently know Java and Prolog. Thanks!

Mary

It's a bit of a tossup. Perl and Python both do pretty much the same thing in about the same amount of code at about the same speed. The primary differences are that (1) Python is far, far easier easier to learn and to read (it's easy to read someone else's python code) while Perl is (as a colleague of mind humerously noted) a "write only language" (2) On the other hand, Perl has been around three times longer than Python, and is more entrenched in the market. So where the job market is concerned, Perl is probably more attractive from that perspective. →Raul654 22:48, 7 October 2005 (UTC)
Python is fun. Perl is not. I'd go with the former. Garrett Albright 01:34, 8 October 2005 (UTC)
Do a search for Perl and Python on a recruitment website and see which ones look most interesting. Perl jobs tend to be mostly Internet service providers (and spammers if you're evil). The mobile phone industry is starting to use Python apparently, and I agree that it's nicer to use than Perl. You can also play with Ruby, which is somewhere in the middle, or Lisp if you're a follower of Philip Greenspun and Paul Graham. Ojw 15:03, 8 October 2005 (UTC)
Nonsense. How is Perl "not fun"? How do you quantify a language being "fun" anyway? Dysprosia 04:08, 9 October 2005 (UTC)
Oh, I won't lie and say that I wasn't being subjective. But the fact remains that Perl has a much higher level of entry than any other major language out there; it's like you can't help but write obfuscated code. The OP said she already knows some other languages, so I'd bet she could pick up Python in a snap because it's quite easy to "read." Perl, not so much. And since productive programming is fun programming, she'd be able to start having fun in Python much sooner, I'd bet. Garrett Albright 08:10, 9 October 2005 (UTC)
I doubt that. To do something in Perl requires the same basic knowledge to do the same in Python. Perl is quite easy to read too, if you write it in a certain way. (It's not that I'm trying to be Perl-partisan here, I'm not, I just feel that some criticism of Perl tends to be overrated.) Dysprosia 11:34, 9 October 2005 (UTC)

Why do men have nipples?[edit]

Ya, I said it! But I would seriously like to know. - Cobra Ky Flag of the United States.svg (talk, contribs) 17:21, 7 October 2005 (UTC)

Men actually have complete breasts, not just nipples...they are just underdeveloped. --Phroziac(talk)Flag of Phyzech Republic.svg 17:27, 7 October 2005 (UTC)
Well, usually! Manboobs! — ceejayoz .com 03:35, 9 October 2005 (UTC)

Why? - Cobra Ky Flag of the United States.svg (talk, contribs) 17:28, 7 October 2005 (UTC)

I think sexual differentiation could answer some of your questions. Most male and female organs develop from the same undifferentiated fetal organs; they simply develop differently under the influence of hormones. Female hormones stimulate the development of breasts during puberty, so women's proto-breasts develop while men's don't. — Laura Scudder | Talk 18:13, 7 October 2005 (UTC)

The short answer is that there has been no biological reason to eliminate them. The genes for nipples are very ancient ones common to both sexes of all mammals and are not carried on the Y chromosome. The basic equipment of a nipple is biologically cheap. It is made operational when needed by hormone signals. A defect of nipple or breast development carries little reproductive penalty to a man but a strong reproductive penalty to the other 50% of the population, so nipples continue to be advantageous and evolutionarily conserved. An intelligent designer of course would not bother to design a male with them: this type of trait is far better explained by evolution than by any competing hypothesis. alteripse 19:43, 7 October 2005 (UTC)

  • But what if that "designer" was intelligent but lazy? Ha! And who was his/her manufacturer if that designer only did the design and ordered the products from an overseas supplier? Anyway, if he/she was so intelligent and also predetermined our destinies, all nuns and priests would have no sexual organs at birth. The only possible explaination: This designer is lazy. -- Toytoy 09:54, 18 October 2005 (UTC)
The biological reason to eliminate them is not strong enough to cause them to be eliminated, much like the appendix.

Thanks for the answers everyone. I believe I thoroughly understand now. The reference to intelligent design was quite interesting as well; another score for evolution theory. - Cobra Ky Flag of the United States.svg (talk, contribs) 23:05, 7 October 2005 (UTC)

I think User:Alteripse is giving the field of intelligent design far too much credit by supposing it makes any testable claims about the nature of the designer. Gdr 13:12, 8 October 2005 (UTC)

There is an interesting parallel in industry, where it is frequently cheaper to make everything the same, even if that means some "additional equipment" is included that was not "ordered". For example, circuit boards are often built with everything and then those options the customer doesn't want are burned off or otherwise disabled. It doesn't seem intuitive that this is efficent, but the cost of producing many different types of circuit boards apparently is more than the cost of destroying unwanted components. StuRat 05:12, 9 October 2005 (UTC)

Men have nipples because in the early stages of developments inside the womb Males and females are basically indistinguishable. In other words, we all start out from the same "template".
Well yes, but the more interesting question is why we all start out the same. It would also be possible for male bodies to eliminate nipples later in life, much as we lose baby teeth, if there was some value to doing so. StuRat 13:48, 14 October 2005 (UTC)

Can Big Red gum cause permanent tongue damage?[edit]

If you cover your tongue with Big Red chewing gum and stick it out of your mouth for an extended period of time could it cause permanent damage?

  • I am not sure what mechanism of harm is worrying you, but the surface of the tongue heals even faster than the surface of the skin. alteripse 19:44, 7 October 2005 (UTC)
    • Really? I didn't knew that. Could you add what you know to tongue? ☢ Kieff | Talk 23:02, 7 October 2005 (UTC)
      • It's just that the tongue and inside of the mouth are mucous membrane tissue. Although not as tough as epidermis, mucosal membranes have a blood supply that is more plentiful and closer to the surface and have a higher density of immune cells and are more resistant to wound infection. I suspect (off the top of my head) that there are higher densities of precursor cells and faster responses to injury in mucosal membrane compared to skin. In practical terms, this is why doctors in emergency rooms dont even bother to suture cuts in the inside of the mouth unless the tongue is almost severed (I am exaggerating only a bit here). alteripse 00:55, 8 October 2005 (UTC)
  • Yeah, probably not. It is unlikely any worse than burning one's tongue on very hot food -- it might hurt like an SOB for a few days but it heals pretty quick. --Fastfission 19:47, 7 October 2005 (UTC)

Frosty Question[edit]

On bright, still, autumn mornings just before the sun comes up I notice that the dew on my car windscreen is not frozen and then as the sun rises above the horizon the dew freezes. Is it possible that the solar wind passing the edge of the earth can cause the tempter to fall? I have noticed this happen on dozens of occasions over the years. Is there a link? --Eye 20:31, 7 October 2005 (UTC)

The short answer to your question, I believe, is no. Sunlight isn't going to make anything on earth colder. Sadly, I have no idea what actually is going on. -- SCZenz 23:07, 7 October 2005 (UTC)
If you think about it, the Earth doesn't start warming up from the Sun's rays untill well after sunrise. Thus, it could be just that the Earth is still cooling down, and the sunrise and freezing are unrelated. --Borbrav 04:01, 8 October 2005 (UTC)
Dew freezing on the windscreen is a rare occurance in my part of the world, but I do know that in the middle of winter (in my location of Perth at least) the day's lowest temperature occurs about 20-30 minutes after sunrise so I wouldn't think it's a solar wind thing.--Commander Keane 06:11, 8 October 2005 (UTC)
You spend your sunrises looking through a car window? Did you cheat on your wife and get kicked out of the house? :) I wish :-) --Eye 21:16, 8 October 2005 (UTC)
But more seriously, I'm thinking about the influence of wind. I've often noticed that around sunset/rise the air suddenly becomes very still. Maybe a slight wind prevented the previous formation of frost.
This makes me think of something else I've often noticed. When you boil water and then turn off the gas (if you use gas, that is - an electric stove works too slow for this) you suddenly get (more) steam. The reason for that, I assume, is that previously the hot air rising along the sides of the pot prevented the steam from forming. But if you turn off the gas, the water at first still boils and keeps on saturating the air. And the saturated air finally gets a chance to form steam. DirkvdM 18:01, 8 October 2005 (UTC)

Maybe frost isn’t the right word. What happens is that the dew freezes. The drop in temperature is very slight but enough and occurs after the sun has risen. A drop in the wind might be a more feasible answer but that is so with most frosty days. Maybe there is a weather person out there? --Eye 21:16, 8 October 2005 (UTC)

Shortly after dawn the sunlight is coming in at such a shallow angle that it provides little heating, such that the thermal loss into space is greater. That means the temperature, on average, will continue to drop until the Sun gets to a more respectable angle. I said "on average", since local weather fronts can easily overwhelm this slight effect. StuRat 05:03, 9 October 2005 (UTC)

I had an interesting frost phenomenon on a car of mine. Frost would form on the hood then melt as the air warmed up, except for the areas of the hood with the cross supports under them, since they kept those parts of the hood cool a few minutes longer. The result was a frost X-ray of the hood ! StuRat 05:19, 9 October 2005 (UTC)

carbohydrate chart[edit]

How many grams of carbohydrate are in various common foods?

  • Any site on the Atkins diet would keep such a list. You'd have to be more specific about which foods you're talking about if you want a useful answers from us. - Mgm|(talk) 22:12, 7 October 2005 (UTC)

Google carbohydrate content or carbohydrate list. You will find dozens of such lists, if not hundreds. alteripse 00:49, 8 October 2005 (UTC)

This site provides a fairly comprehensive list of nutritional info for many foods:
http://www.nutritiondata.com
StuRat 04:58, 9 October 2005 (UTC)

carbon trading[edit]

WHAT IS THE SCOPE FOR INDIAN INDUSTRIES IN CARBON TRADING?

BY, SRUJANA FINAL YEAR B.E(CSE) PLEASE GIVE ME ANSWER TO MY MAIL-ID

  • I've also seen this question in the Humanities reference desk, please only post it in one reference desk subsection. - Mgm|(talk) 08:15, 8 October 2005 (UTC)
  • Srujana,

I have removed your e-mail as answers are not returned and you will start becoming more of a target for spam. Our Carbons emission trading article is a good start and our Economy of India article should give you some idea of the challenges. This release from the International Emissions Trading Association states that India has started trading [27]. These newspaper articles show that Biofuel and tree plantations are targets see [28] and [29]. Capitalistroadster 05:32, 9 October 2005 (UTC)

I'm not sure what you are refering to specifically but Kyoto Protocol doesn't require developing countries such as India to restrict its carbon emissions. Only those of Annex 1 in the Protocol that are required to cap their emissions. __earth 14:37, 11 October 2005 (UTC)

Smoke[edit]

Is there a way to add a color to smoke? For example, adding a substance to a cigarette to colorize the smoke. Is this possible?

Sure, but most people think it would make cigarettes even more offensive. alteripse 12:31, 8 October 2005 (UTC)

Fireworks? DirkvdM 13:44, 8 October 2005 (UTC)

See the "common pyrotechnic compounds" section of our fireworks article. Shantavira 16:56, 8 October 2005 (UTC)
Note that you don't want to add most of those compounds to a cigarette. Doing so would tend to make them much more rapidly and efficiently deadly than they already are. Note as well that those compounds will give a coloured flame, but won't typically have an appreciable effect on the smoke. TenOfAllTrades(talk) 03:24, 9 October 2005 (UTC)
There are some colored gases, like the purple of iodine or the green of chlorine, but those aren't the type of things you would want to inhale. StuRat 04:51, 9 October 2005 (UTC)
The question mentions cigarette smoke only as an example, so the answer should not focus on that. And certainly not the act of smoking, because that can hardly be the intent, unless it's a machine that smokes for some research or something. What is the reason for the question? DirkvdM 13:06, 9 October 2005 (UTC)
If you're asking because you want to film or photograph the smoke, then you could use coloured light to give the smoke a tint. Ojw 13:27, 9 October 2005 (UTC)

Generic Drugs[edit]

Is there a real difference between a generic and brand drug? I know they have to have the same active ingredient and have to be the same quality and everything, but then why do some doctors insist that a patient takes the brand and not the generic version? And why do so many people claim that the generic version of a drug do not work?

Some time ago there was a discussion in Dutch politics if doctors should not be forbidden to prescribe those unnecessarily expensive drugs and if national health insurance should cover that (or only restitute the normal price). I don't know what the outcome was (or indeed how informed the politicians were). Doctors may receive money for pushing certain brands. And if the drug is sold by themselves, they will likely make a bigger profit from a more expensive drug (which is why that is not the way it works in the Netherlands). People in general may make such claims because with health one should not take risks and therefore the more expensive option should be chosen (as if that is ever any guarantee - especially when you don't really know what you're buying). But now I'm only guessing. It's comparable to the inflated prices of condoms and funerals - not the sort of thing with which people are inclined to complain about the price. Fyi, I pay about 0.10 € each for my condoms. Well, for that I need to buy a gros, but they keep for years and the point is that it's a good indication what a reasonable price would be. DirkvdM 13:58, 8 October 2005 (UTC)

Is there a difference? In a word, sometimes. Most of the time for most drugs and most people a generic will work as well at a lower price. For some drugs in some people the difference between a generic and brand name may more than trivial. The problem is that it is difficult to predict ahead of time. alteripse 05:51, 9 October 2005 (UTC)

Our Generic drug article states that they are bioequivalent to the brand drug. However, in 50% of cases there is no generic drug as the term of the patent has not expired. There may also be a newer drug which may be more effective but may also be more expensive. In short, it depends on the circumstances. Capitalistroadster 06:11, 9 October 2005 (UTC)

Postural Drop related to Scleroderma and Kidney Disease[edit]

Dear Wikipedia Volunteer,

I have just found out about your service in a Sydney newspaper and am very excited at its potential.

Having just searched in Wikipedia for "postural drop" no results were available, although I am aware that Google, at least, does provide some references.

I sincerely hope that some of your readers, or whoever, can throw some light on this serious and deilitating condition.

Kind Regards, Arthur Major --203.164.32.81 07:19, 8 October 2005 (UTC)

See orthostatic hypotension. alteripse 12:32, 8 October 2005 (UTC)

WBC Booster[edit]

Sorry if this is a repeat post, but I accidently posted this in another category.

I know there are drugs that some athletes take to increase their red blood cell count, but are there any drugs that increase the number of white blood cells?

Coming out with generics[edit]

I was wondering why sometimes it takes so long for a generic drug to come out. I read something about the patents for allegra and I think flonase expiring and it was about a year ago I think, but generic versions are not available yet, why is this?

  • Even when derived from the patented brand, generic drugs still need to do research to use the information to make a useful drug after which they need to have it tested and get all sorts of forms from government and health organizations. It's just a long, long process. - Mgm|(talk) 19:37, 8 October 2005 (UTC)
    • It isn't always profitable to do so, either, especially if the brand name drug is fairly cheap already. — ceejayoz .com 03:33, 9 October 2005 (UTC)

Muscles wasting[edit]

My cousins muscles are wasting away and the doctors told him he will eventually be in a wheelchair. The doctors also said there are no drugs currently that could help him and the only thing he could do is physical therepy. I was wondering if something like steroids would help him out? I know they are illegal and arent very safe or healthy, but would it work and stop or slow down the wasting of his muscles?

Anabolic steroids are used sometimes for medical purposes, so I think that if they could help your cousin, his doctors would have thought of that too. Why not ask them about it? David Sneek 12:16, 8 October 2005 (UTC)

If your cousin has a muscular dystrophy there have been many clnical trials of anabolic steroids as well as glucocorticoids and growth hormone. They have not been found beneficial and sometimes have accelerated loss of strength. Search Medline for these terms if you want to find out for yourself. The muscular dystrophies are truly nasty diseases with few treatment options except support for most; I am sorry for your cousin. alteripse 12:30, 8 October 2005 (UTC)

  • It sounds like Muscular dystrophy probably Duchenne muscular dystrophy to me. In answer to your question, this fact sheet from the Muscular Dystrophy campaign outlines that steroids are being used to treat muscular dystrophy see [30]. I have two young nephews with the disease and the good news is that research in a number of areas is delivering promising results. Wyeth are conducting human clinical trials of a treatment in adult muscular dystrophy see [31] According the National Institutes of Health, there are 13 clinical trials underway for various forms of muscular dystrohy see [32]. There have been positive outcomes in animal trials for gene therapy in recent times as well. Capitalistroadster 07:15, 9 October 2005 (UTC)

This is a nicer answer, with refs, than my gloomy one. Note that the "steroids being used to treat muscular dystrophy" in the MDA ref are glucocorticoids rather than anabolic steroids. The disease and both types of steroids have been well known for about 60 years. I didn't realize anyone was still running trials on glucocorticoids, but I didn't try to look it up. I hope some the cited research changes the traditionally pessimistic picture to which I alluded. alteripse 12:33, 9 October 2005 (UTC)

Pharmacy School[edit]

I'm interesting in applying for pharmacy school in the next few years, I was wondering how to increase my chances of getting in. I know good grades and a good PCAT score are important and also volunteering in a pharmacy, but what else can I do to increase my chances of getting in a good school?

Also, what questions do they ask at the interview? Thanks

Here is the same advice I would give if you asked about medical school or veterinary school. Concentrate on your grades, especially math and science. Most of the applicants whose grades and scores are within 10% of the average for last entering class will be offered admission, as will some of those whose grades and scores are below that. The principal purpose of the interview is identify unusual positive or negative characteristics that they cannot easily determine by the paper application, or cannot legally or publicly admit to using. Many of these characteristics are those you don't have control over. Another purpose of having an interview is to introduce a subjective element into the process so that taking one person over another with higher numbers can be justified.

If your grades and scores are at least average for the entering classes for that school, the prinicipal purpose of the in-person interview is to detect a disqualifying characteristic. This may differ widely depending on time, place, and local circumstances. One example might be race. Another might be an inability to hold a basic conversation and communicate. Another might be an appearance that suggests potential problems fitting in with the class and reflecting positively on the school. Another might be an extreme disability or an apparent mental illness. Another might be an indication that you would be unlikely to accept an offer of admission. In other words, the admission is yours to lose by the interview.

On the other hand, if your grades and scores are substantially below average for their usual entering class, the principal purpose of the interview is to look for an undetected asset. This may differ widely depending on time, place, and local circumstance. One example, especially in the US, may be race. Another might be an unusually impressive or attractive personal manner. Another might be to confirm other non-quantitative accomplishments. Another asset might be a family connection with the school or something to convince them you are more likely to accept and complete school than the other below-average candidates. Another might be wealth or political connection that could be of advantage to the school. In other words, a small number of students with well-below-average scores will win admission based on other things detected at the interview.

In other words the exact answers to the questions are not the point; it is the chance to detect other things. Work hard so you are in the first group and don't worry about the interview. alteripse 11:43, 8 October 2005 (UTC)

internet[edit]

  • You found it. Any questions? Qaz (talk) 08:23, 8 October 2005 (UTC)
  • By just getting here to ask the question, you must have used the internet. Like the person who asked what is operating system had to ahve used a computer to use the internet to get here to post the question. So we have people driving over the information superhighway who are not familiar with the terminology of the infrastructure involved, comparable to a person who drives a personal automobile, but does not know what a highway is. What is computer literacy coming to? AlMac|(talk) 15:41, 8 October 2005 (UTC)

Maths: Asymptotic Series[edit]

Can anyone help me solve this:

You are given a function

f(x) = (x+1)e^\frac{-1}{x}.

Find a\,, b\, and c\, so that the formula

f(x) = ax + b + \frac{c}{x} + o\left ( \frac{1}{x} \right )

is true when x \to -\infty.

Thank you.


Here's a hint to help you with your homework: consider the Taylor series for e^\frac{-1}{x}. Gdr 14:00, 8 October 2005 (UTC)

The question makes no sense. How can ax and o(x) be in there both? Anyway,

e^\frac{-1}{x} = 1 - \frac{1}{x} + \frac{1}{x^2} + ... , so

f(x) = x + \frac{1}{x^2} + ...

meaning a = 1\,, b = c = 0\,. 82.210.119.82 15:10, 8 October 2005 (UTC)

See our article Big O notation for an explanation of little o notation, but essentially f(x) = o(g(x))\ \iff \frac{f(x)}{g(x)} \to 0\, as x \to \infty\,. Little o notation is mostly used by mathematicians; a computer scientist would have used big O notation and written O \left ( \frac{1}{x^2} \right )\, here (with much the same meaning).
As for your derivation, you've got the Taylor series for e^x wrong. Gdr 15:56, 8 October 2005 (UTC)

But if e^\frac{1}{x}\,, how does x \to -\infty change the thing — in what way is it different from x \to \infty?

Chemistry: Small Mushroom Cloud?[edit]

I recall seeing a video of a (probably high school) chemistry lab. A teacher poured the contents of one beaker into the contents of another and it bubbled up and over the edge of the beaker and created a small mushroom cloud. What chemicals can be used to achieve something like this and what are the safety precautions surrounding it? Sorry, I can't find the video but thanks in advance. -Haon 14:48, 8 October 2005 (UTC)

It would probably strongly depend on the conditions in the lab, including controlling drafts etc, so it might have just been luck. If you want the gas to fall below the top of the beaker, you'd want the gas to be cooler than the surrounding air, so probably good old dry ice in water would do the trick.
So at a normal room temperature, dry ice combined with water would create a mushroom cloud? -Haon 19:43, 8 October 2005 (UTC)
The main things needed for a visible mushroom cloud are:
1) The gas to rise must be much hotter than the ambient air temp.
2) The gas to rise must be visible.
3) The air must be relatively calm.
StuRat 04:40, 9 October 2005 (UTC)
So according to number one this couldn't be dry ice? Unless I'm terribly mistaken and dry ice mixed with water is much hotter than a normal ambient air temperature. -Haon 00:01, 11 October 2005 (UTC)
I would expect dry ice mixed with water to freeze the water, no mushroom cloud there. Dry ice can create a cloud of cold vapor, which sinks instead of rising, no mushroom coud there either, unless you are talking about an upside down mushroom cloud, where it falls to the floor then spreads out. StuRat 00:09, 13 October 2005 (UTC)
Water and dry ice make a vapor (Check out Dry Ice#Uses. I just don't know if this vapor could create this effect. -Haon 12:21, 13 October 2005 (UTC)
The vapor will be colder than air, so will sink, as previously stated. The only mushroom cloud I would predict would be an upside down one, also as previously stated. StuRat 14:24, 14 October 2005 (UTC)

Q1werty[edit]

Q1werty was here--Q1werty was here 15:38, 8 October 2005 (UTC)

You might be interested in the sandbox. AlMac|(talk) 15:43, 8 October 2005 (UTC)

L-alanine Vs. Beta-alanine[edit]

What is the difference between L-alanine and Beta-alanine?--65.33.222.71 15:45, 8 October 2005 (UTC)

The position of the amino group on the carbon chain: see alanine and beta-alanine (although the latter doesn't have a structure diagram). Physchim62 17:25, 8 October 2005 (UTC)

timber joineries and defects of timber[edit]

can you please help with informative sites on timber joineries and defects of timber

       thanking you amrita
  • Amrita,

You might wish to check our Woodworking and Joinery articles for a start. Capitalistroadster 07:22, 9 October 2005 (UTC)

Gradient Invariance?[edit]

What is gradient invariance?

Invariance means 'staying the same' and a gradient can mean lots of things, but usually means a gradual change or something that can be represented with an arrow. What's the context? DirkvdM 17:31, 8 October 2005 (UTC)
I think it means that if \vec A (\vec r)\, is vector potential of a field \vec v (\vec r)\,, then so is the \vec A(\vec r) +\, \mathrm{grad}\, f(\vec r)\,.

Compuer Science - locks and operating systems[edit]

In computer science and operating systems, what is a lock? Is it the same as a semaphore? --HappyCamper 17:45, 8 October 2005 (UTC)

No, they're slightly different. A lock (also known as a mutex) is a logical construct -- you want sole access to a resource, so you "lock" it. Locks are usually implimented using semaphores, which are operating-system-supported atomic operations (and are fairly difficult to program with) →Raul654 17:48, 8 October 2005 (UTC)
Locks are often set by application software without dependency on anything in the operating system. For example if the "in-use" field of a particular customer order is "on" that means some set of programs from one user is in middle of updating stuff in the order (which could span multiple files or tables), and all other programs in the application have to stay out until the user is completed.
Program steps
  1. Is flag ok for me to access?
    1. if not, then message user about situation, and exit attempt
    2. if Ok to access, then set flag "in use" (by me)
    3. at end of access to that order, set flag "available" for others to mess with that order
  2. problem ... sometimes user access breaks (Windoze gets hung, communication link times out, someone kicks wall plug), the program ends abnormally, and the flag is never reset.

AlMac|(talk) 02:38, 9 October 2005 (UTC)

Biology: Benedicts and glucose[edit]

May I have the balanced symbol equation for the reduction of Benedict's solution by glucose, please?

Wikipedia won't do your homework for you. See Chemical_equation#Balancing_Chemical_Equations to get started. — ceejayoz .com 03:31, 9 October 2005 (UTC)

Polarization of Electrons[edit]

In physics we've just been learning about the wave-particle duality of electrons and it made me wonder - can the wave 'side' of an electron be polarized like light? And if not why not, is it not a transverse wave, is particle physics just too abstract at this level for us to understand or what? ;) --BigBlueFish 19:54, 8 October 2005 (UTC)

Yes, electron beams can be polarized, and generally are in electron-positron colliders. It corresponds, if you're thinking about them as particles, to the spins all being aligned in one direction. (You can also think of polarized light as photons whose spins are aligned.) -- SCZenz 21:20, 8 October 2005 (UTC)

bees[edit]

bees can sting you. be careful. -Lethe | Talk 23:46, 8 October 2005 (UTC)

  • No kidding! I got stung by one just the other day. He charged me 5 quid for a jar of honey! *boomtish*... thankyou, I'll be here all week. Try the veal! Noodhoog 14:05, 11 October 2005 (UTC)

A Dense Question[edit]

that hot air rises and cold air sinks. I also under stand that the same convection forces are at work in the earth and cause magma plumes to rise up to produce volcano’s. Where it all falls apart for me is that as gravity is at work on hot air in that when it cools it pulls the cold, dense air, back to the ground. How does this work in the earth when the force of gravity diminishes the closer you get to the centre?--Eye 21:40, 8 October 2005 (UTC)

That's true, there is no gravity at the center of the Earth, and therefore no buoyant force to make the magma rise. But the magma that comes out of volcanos is not from the center of the Earth, but rather from the mantle, under the crust, where there is indeed gravity and buoancy.

-Lethe | Talk 23:33, 8 October 2005 (UTC)

I think that you have a fundamental misunderstanding of gravity. Gravity does not diminish the closer you get to the center of the earth, infact, in increases very rapidly. The force of gravity is inversly proportional to the square of the distance, which mean that if you go halfway down to the center of the earth, gravity will not be not only stronger, but 4 times as strong! gkhan 00:12, 9 October 2005 (UTC)
Sorry, gkhan, but that's all wrong. It's true that the Earth is sometimes modelled as a point mass with all the mass at the center. However, this model is only accurate when you are far from the center of the Earth, and preferably at the surface or above. However, if we insisted on using that poor approximation even when we were at the center of the Earth, the calcs would give us an infinite force of gravity, since our distance from the pt mass at the center would be zero. This would cause the Earth to collapse inward on itself into a black hole, leaving only those people behind who don't insist on using the pt-mass model when it isn't applicable, LOL. An accurate model would find the gravity vector between the person at the center of the Earth and each atom in the Earth, using the distance to each atom to determine the strength. All these vectors would then be added and would total zero, if an equal number of atoms were on each side. StuRat 04:18, 9 October 2005 (UTC)
You are ofcourse right. It's been a few years, I apologise :P gkhan 10:08, 9 October 2005 (UTC)
No prob, glad to help you shake off some of the rust on your physics memory. StuRat 16:10, 9 October 2005 (UTC)
Suppose we are walking along the inside of a hollowed out asteroid that is in perfect mass balance, not spinning, The total mass under foot is tiny compared to the rest of the mass ... the center of gravity is to be floating in the middle of the hollowed out space.
But center of Earth is different matter. Gravity has crushed the material of which the Earth is made to high density near center of earth. It is not hollowed out. AlMac|(talk) 02:44, 9 October 2005 (UTC)
It would be more correct to say the forces of gravity would be balanced at the center of the Earth, hence there is no NET gravitational force. So, indeed, a person in the center of the Earth would be weightless. However, the immense pressure from all the material is believed to make the core of the Earth solid. Only the molten mantle between the core and the crust experiences convection, and, as noted previously, there is still considerable gravity at the mantle. StuRat 04:04, 9 October 2005 (UTC)

That’s a better way of putting it …there is no net gravitational force at the centre of the earth…which I presumes means that the mass of the earth above the point of centre pulls up in all directions causing the illusion of weightlessness of any object the happens to occupy the earths centre. Mmm…anti-gravity? :-) The force of gravity must exist then, like a crust around an object with mass like the earth. The maximum pressure must be exerted from near the surface and weaken towards the middle as the increase of mass above a given point pulls up on the mass below reducing the pressure. There should then be a neutral point be where the mass above a certain point would equal the mass below. A sort of gravitational boundary layer and this point would be determined by mass not size, i.e. that point would not be equal distance from surface to centre. Would this be where the iron core begins, and if so could the iron core be colder than people expect if the pressure on it is weakened by lower gravitational forces? --Eye 19:49, 9 October 2005 (UTC)

Well, since the iron at the center is more dense, you would still expect the point of zero net gravity to be very near the geometric center of the Earth. I would also expect the iron core to be at least at hot as the material above it, since the heat has no way to dissipate, other than up through the Earth's surface. StuRat 23:58, 12 October 2005 (UTC)

Quote about solipsism involving Bertrand Russell[edit]

On the page Talk:Solipsism there is mention of a quote I've been looking for for some time. I recall quite clearly reading just a few months back about a telegram that a female logician sent to Bertrand Russell that said something very like "Have converted to solipsism. Am enjoying it immensely. Don't understand why more people don't do the same." Unfortunately, I can't find this on Google, Wikipedia, or any books I have in the house. Can anyone confirm/deny? George

I typed "betrand russell" solipsism into google and found this:
Bertrand Russell was giving a lesson on solipsism to a lay audience, and a woman got up and said she was delighted to hear Bertrand Russell say he was a solipsist; she was one too, and she wished there were more of us. - Beyond Reductionism
-- W. H. Thorpe
was that it? -Lethe | Talk 23:29, 8 October 2005 (UTC)
That's the thing. I can find references like that - to a layperson saying something dumb - but I have the clearest memory of reading about it in the joke telegram context. I do thank you for your help, though. George 00:38, 10 October 2005 (UTC)

limits in topology versus limits in category theory[edit]

Is there a way that you can interpret the limit of a sequence in a topological space as a limit of some appropriate functor between some categories? -Lethe | Talk 23:16, 8 October 2005 (UTC)

Identifying some fish and seaweed species[edit]

It would be great if someone could tell me what species some or all of the following are:

Algerian seaweed.jpg
Mustila.jpg
Ferxa.jpg
Four Algerian fish.jpg

All were caught/picked off the coast of central Algeria. - Boualem 00:12, 9 October 2005 (UTC)

Genotypes[edit]

Here is the situation: A brown-eyed man whose father was brwn-eyed and mother was blue eyed married a woman whose father and mother were both brown-eyed. The couple has a blue-eyed son.

For which of the individuals mentioned can you be sure of the genotypes?

What are their genotypes? What genotypes are possible for the others?

Thank you for your time in advance

Well I'll get you started on your homework! The trait for blue eyes in humans is recessive, so any blue eyed-person must be bb in genotype. Brown-eyed people can be homozygous or heterozygous for the dominant gene B. Take it from there! Physchim62 00:41, 9 October 2005 (UTC)
What Physchim62 said is correct. For the purposes of me explaining, the brown-eyed gene shall be called B and blue-eyed gene called b. The original brown-eyed man first mentioned (who has brown-eyed father and blue-eyed mother), what would be his genotype? Well, for a brown-eyed person, it can either be Bb or BB (since B is dominant). But his mother, who is blue-eyed, must be bb is genotype since blue-eye gene is recessive. The man has to get a gene from his mother, therefore his genotype is Bb. OK, now this man marries a woman, you say. You don't tell us her genotype, but we don't need to know. This couple has a blue-eyed son. This son's genotype must be bb, as we established earlier with blue-eyed people. So this son must have got one of his b genes from the father, and one from the mother. We already know the father's genotype is Bb. So what about the mother? Well, since a b gene has to come from her, she is either Bb or bb. Even if we know that her mother and father were both brown-eyed, we still can't narrow this down further. She could still be bb, or blue-eyed, even if both parents are brown-eyed (each of her parents would be Bb). All we can say is that at least one of her parents, although we don't know who, is heterozygous for the dominant gene B. It could be either one or both of them. Hope that answers your question. -- Daverocks 13:06, 16 October 2005 (UTC)

Alcohol[edit]

Why is alcohol so fattening? purplefeltangel (talk)(contribs) 03:18, 9 October 2005 (UTC)

It isn't. Non-alcoholic beer is just as fattening as alcoholic beer, for example - it is the other stuff in the drink. Lots of carbohydrates in beer. — ceejayoz .com 03:29, 9 October 2005 (UTC)
I might want to add a proviso to the remark above. Alcohol does have appreciable caloric content all by itself, but the total calorie content depends quite a bit on the beverage. Vodka is essentially pure alcohol (~40%) and water; it will run you about 65 calories per fluid ounce. Beer depends somewhat on how it is brewed. Stouts like Guinness get only about a quarter of their calories from carbohydrates; most of the rest is from alcohol. Sweeter lagers can draw up to about half of their calories from carbohydrates—they contain more sugar. Irish Creams like Bailey's are loaded with sugar and cream; only about a third of the calories are from alcohol, with the balance being from fat and carbohydrates. TenOfAllTrades(talk) 04:34, 9 October 2005 (UTC)

(after edit conflict)

In virtually all plants and animals, glucose is transformed into energy in three steps: glycolysis, the citric acid cycle and oxidative phosphorylation. Yeast cells produce alcohol from glucose when there is little or no oxygen: they only use glycolysis to do this, and gain much less energy as a result, only 6% of the energy released by the three steps together. When the alcohol is consumed by another animal, it is broken down by the citric acid cycle and oxidative phosphorylation: the animal which consumes the alcohol is gaining the energy which the yeast could not obtain from the sugar, ie the other 94%. Hence drinking alcoholic drinks is almost as fattening as drinking sugar solutions... Physchim62 03:37, 9 October 2005 (UTC)
Um, can you explain that in plain English please? purplefeltangel (talk)(contribs) 03:43, 9 October 2005 (UTC)
Sure, the body converts alcohol into sugar, so it's just like you drank a glass full of sugar-water, which would also be fattening. StuRat 03:53, 9 October 2005 (UTC)
When turn sugar into carbon dioxide and water, you release 36 "units" of energy. When the yeast turns sugar into alcohol, it only releases 2 "units" of energy. When you drink the alcohol, your body releases the other 34 "units" that were present in the sugar. The Calories in our food are also measures of the energy released by our body when we digest the food: if we release more energy than we need, we store it as fat.... So alcohol contains almost as much energy as sugar, even if it doesn't taste sweet, and so is at least as likely to make us put on weight. Is that any better for you? Physchim62 03:51, 9 October 2005 (UTC)

Or, to put it another way. The yeast, being suck in an environment with no oxygen (by our design since we want the alcohol) relies on this trick where they can get a tiny amount of energy by doing a metabolism that results in alcohol as its end product. They do this because a little energy is better than starving to death. Later, we drink the stuff and we are able to extract the rest of the energy that the yeast was not able to get to. Since the yeast gets only about 6% of the potential, it is a good way to fatten oneself up. Qaz (talk) 04:00, 9 October 2005 (UTC)

Thank you. ^__^ purplefeltangel (talk)(contribs) 05:08, 9 October 2005 (UTC)

I seem to remember learning in 9th grade health class that when you're drunk, your metabolism slows and converts existing stores to fat at a higher rate. This might also contribute. -Lethe | Talk 05:10, 9 October 2005 (UTC)
This is the reason I remember too, due to the liver having to process the alcohol. Dysprosia 11:29, 10 October 2005 (UTC)
I would also add a lifestyle factor. The heavier drinkers I know tend not to be the people that go jogging or to the gym. --bodnotbod 00:59, 13 October 2005 (UTC)

Tests for Lymes Disease strain idenification[edit]

I am looking for the name of a test for strain idenification to idenifty where I got Lymnes. Can you help with this test name?

Thanks, 04:52, 9 October 2005 (UTC)65.7.78.21

Excel problem[edit]

I accidentally did something to my excel options (I have no idea how) and now when I press the up/down/left/right arrows on my keyboard, the view scroll as opposed to what normally happens, which is the current cell moving. Does anyone know how to change the settings back. The version is Excel 2002. Thank you :-) Akamad 04:54, 9 October 2005 (UTC)

Sounds like you have Scroll Lock turned on, IIRC. I don't have Excel handy to verify that though. — 15pxmendel 04:59, 9 October 2005 (UTC)
mendel is right, I just tested it out. Turn scroll lock off to fix.--inksT 05:00, 9 October 2005 (UTC)
Thanks all. That did the trick. Akamad 05:01, 9 October 2005 (UTC)
It says something about the obsolescense of the Scroll Lock key that a person inadvertently using it for the purpose for which it was designed sees that usage as a problem. Down with Scroll Lock! Brian Schlosser42 16:45, 10 October 2005 (UTC)

Swarovski Crystal vs Teeth[edit]

Just a question. I recently bought my girlfriend a little expensive lump of Swarovski Crystal carved into the shape of a rabbit. If we get a real rabbit, put the crystal into it's cage, and the rabbit chews on the crystal, will the crystal be scratched? I'm thinking Silicates vs Calcium compounds, but have no idea of the answer. Any thoughts appreciated. :) --inksT 05:03, 9 October 2005 (UTC)

Looking at the Mohs_scale_of_mineral_hardness we see that glass has a hardness of 6 or 7. Hydroxylapatite, the main constituent of enamel, has a hardness of 5. The rabbit, however, could break the glass with a sudden bite rather than slow scratching. --Borbrav 05:38, 9 October 2005 (UTC)
Indeed. Many people do not realize for example that although diamonds resist scratching better than any other common material, they are nonetheless vulnerable to breaking by the application of surprisingly little force. It is a good thing too or they would be much harder to cut into pleasing shapes for our Bling Bling. Qaz (talk) 05:42, 9 October 2005 (UTC)
Thanks guys :) --inksT 07:43, 9 October 2005 (UTC)

general question[edit]

what is the reason for ice vessels are not licked?

Because your tongue would freeze to the side. Gdr 11:41, 9 October 2005 (UTC)
This usually only applies to materials with high themal conductivity, like metal. Materials with low themal conductivity, like styrofoam, could be very cold before licking them would freeze your tongue to them. StuRat 17:00, 9 October 2005 (UTC)

Seed Law[edit]

What is seed law?

In what context do you mean seed? Could you provide a little more information so that someone can answer you more specifically? Then again, a search for "seed law" returned a considerable number of hits, quite a few of which appear to be related to civil law in the United States. Rob Church Talk | FAD 16:06, 9 October 2005 (UTC)

Stomach acid[edit]

I read in my biology book that stomach acid is supposed to kill bacteria, then why do people get food poisoning if the acid is supposed to destroy all bacteria?

Because the bacteria can spread to all sorts of places before they even reach the stomach. - Mgm|(talk) 11:29, 9 October 2005 (UTC)

There are several ways this can happen:

  • Some kinds of food poisoning are caused by exotoxins, poisonous substances excreted by bacteria before you eat them, for example botulin produced by Clostridium botulinum.
  • Some bacteria, for example Staphylococcus aureus, produce toxins in the stomach before they are killed by stomach acid; these toxins are absorbed by the intestine.
  • Some other bacteria have mechanisms that allow them to survive the acidic environment of the stomach. Escherichia coli can survive for several hours at pH 2, long enough to pass through the stomach. Some Salmonella species attach themselves to food particles and thus get some protection from the acid.
  • Helicobacter pylori can survive indefinitely in the stomach (causing peptic ulcers). It survives by screwing itself into the stomach wall and excreting urease, which partially neutralizes the acid in a small region surrounding the bacterium.

Gdr 11:53, 9 October 2005 (UTC)

...And not all food poisoning is bacterial (though I suppose this is a rarer case). See, for example, the cheese fly, whose maggot burrows into cheeses and preserved meats, survives stomach acids, and causes serious intestinal distress. Bunchofgrapes (talk) 22:04, 10 October 2005 (UTC)

Quotation Marks in Word[edit]

How should I force my MS Word to show “” as quot. marks instead of »« when Smart Quotes option is turned on?

Probably need to set it to English rather than French somewhere... either for the whole program, or for the text-style you're using (and don't forget: if you copy/paste anything with those quotes onto web-pages/wikipedia, then they will appear as invalid characters) Ojw 13:11, 9 October 2005 (UTC)
Whenever I switch between language keyboards I find this to be a persistent problem. For example, my main keyboard is in English, so when I start a document it does the correct "English" style smartquotes. However if at any point I switch to another language (in this case, Russian), suddenly I get only Russian smartquotes (as you have above) even after I switch back to the English keyboard. It's very irritating and I couldn't find any way around it, so I just disabled Smart Quotes completely. --Fastfission 14:48, 9 October 2005 (UTC)
I used to work in a computer lab where Word would do stuff like this often. I know there is a "Select Language" function somewhere in Word that will let you switch it back to English, but I can't recall how to access it. Try searching Word's help files for "language." Garrett Albright 15:58, 9 October 2005 (UTC)

Skin Breathing?[edit]

According to the Bond Film Goldfinger, painting someone with Gold kills them by stopping their skin breathing. Surely, if this was true, you would suffocate every time you went swimming? smurrayinchester(User), (Talk) 12:52, 9 October 2005 (UTC)

On the one hand, yes, the Bond film is nonsense. On the other hand, there is a lot of oxygen suspended in water... Shimgray | talk | 13:30, 9 October 2005 (UTC)
Humans don't have gills, so this oxygen is largely useless to us. Rob Church Talk | FAD 16:07, 9 October 2005 (UTC)

If the paint were thick enough to interfere with sweating, then it might lead to hyperthermia (heat stroke). Gdr 15:26, 9 October 2005 (UTC)

  • Yes, it interferes with sweating and may cause hypothermiahyperthermia, but under controlled situations it's hardly lethal as proven by the MythBusters. There's also a urban legend that the lady playing the gold-painted secretary died during filming. While it was quite uncomfortable she lived to do at least six more films and was available for a short interview with the MythBusters to show this particular legend was nonsense and she was still very much alive. - Mgm|(talk) 17:53, 9 October 2005 (UTC)
  • Snopes has a good write-up. --jpgordon∇∆∇∆ 17:54, 9 October 2005 (UTC)

The other question I have is 'If Gold is so expensive, would painting her with a pot of matte emulsion from B&Q be as effective as well as much much cheaper', but I guess he just wanted to show off. smurrayinchester(User), (Talk) 20:00, 9 October 2005 (UTC)

Pucefinger just sounds wrong. And as for Brownfinger... --bodnotbod 01:04, 13 October 2005 (UTC)

How to calculate reliability[edit]

Reliability is a qualitative property, not a quantitative value, so it can't be directly calculated. What are you trying to find the reliability of? Depending upon the type of the information/source, you may need to choose from a number of methods. Rob Church Talk | FAD 16:10, 9 October 2005 (UTC)

No, there are plenty of quantitative measures of reliability (in one of its senses): see failure rate for a discussion. Gdr 16:51, 9 October 2005 (UTC)
One can use the historical reliability of a product to estimate future reliability, but this is somewhat limited by constant changes to the product line. Defects may be repaired, which may increase reliability, while new features may be added, which tend to decrease reliability.
In some cases, more direct ways to estimate the life of a product are available. For example, tires have a rated life (in km/miles) based on how quickly the rubber is expected to wear away with normal use. This type of estimate may be better for a new product, with no historical track record.
StuRat 16:54, 9 October 2005 (UTC)

Reliability of what? A measurement? In a laboratory or something like a survey? If you speak of calculation that suggests you mean something scientific. But even then there are loads of things that can be (un)reliable. DirkvdM 17:19, 9 October 2005 (UTC)

IBM hardware has a concept mean time to failure which is when they expect it to fail, on average. We had a hard disk with a mean time to failure of 13 years. When it began to get close to that old, I was trying to explain to management what that meant, without much success. Guess what? It was lucky 13 years old when we experienced a hard disk crash. AlMac|(talk) 20:42, 10 October 2005 (UTC)

Gravitational force as caused by the electromagnetic force[edit]

A few years ago, I tried to explain gravitational force as caused by the electromagnetic force. I got a force proportional to distance to-the-power minus six (instead of the required minus two). Will the derivation be of any use in making a Unified field theory? —Masatran 14:37, 9 October 2005 (UTC)

The unification of gravity and electromagnetism has been tried before; see Kaluza-Klein theory. The results proved to be less than satisfactory, in the end, but they might be part of the solution what has turned out to be an exceedingly difficult problem. -- SCZenz 17:24, 9 October 2005 (UTC)

Converting image files[edit]

I have a Windows 98 computer. In Windows Explorer, is it possible to convert Microsoft Word files to other file types, and if so, how? HyperHobbes 15:53, 9 October 2005 (UTC)

In general, to convert files from one format to another, open them with an application which can read them (Microsoft Word, in your case), then either do a File + Save As or a File + Export and select the type of output file desired. StuRat 17:28, 9 October 2005 (UTC)
If you have a Word document, but not the program Word itself, you should still be able to open the file (then File + Save as at StuRat said) with WordPad.--Commander Keane 08:48, 10 October 2005 (UTC)

Well, this might seem silly, or impossible, but what I am trying to do is convert a Word image into a PNG. Is this possible? HyperHobbes 15:41, 13 October 2005 (UTC)

You should be able to. I don't have Microsoft Word but I was able to convert a .txt to .png with Notepad. Robmods 18:13, 13 October 2005 (UTC)
Take a screenshot, save as PNG. Ojw 17:29, 14 October 2005 (UTC)

How do I take a screenshot? HyperHobbes 16:19, 15 October 2005 (UTC)

Press the PrtSc (Print Screen) button on the keyboard to take a screenshot of the entire screen into the clipboard. Press Alt+PrtSc to take a screenshot of just the current window. You can then paste it into a program like Ms Paint, and save as a .png file. --Avi 23:15, 16 October 2005 (UTC)
  • Course, Windows 98 version of MSPaint won't save as PNG unless some application has installed a plugin for PNG. XP will. SchmuckyTheCat 23:56, 18 October 2005 (UTC)

How do I enable BitTorrent in Opera 8.5?[edit]

Does Opera 8.5 have BitTorrent disabled, or is it included at all? --pile0nadestalk | contribs 16:46, 9 October 2005 (UTC)

The BitTorrent support was disabled on the final release of 8.5, but it's functional on the 8.10 tp2 release. See [33]Kieff | Talk 20:29, 9 October 2005 (UTC)
I already tried this one but it has ads. Is 8.10 TP2 newer than 8.5? --pile0nadestalk | contribs 22:07, 9 October 2005 (UTC)
No it isn't. You could always stick with 8.5 and wait until the next version of Opera, where all these features will be present. Also, the BT support in Opera wasn't so good, apparently, and it was just experimental. I think for next version you can expect something solid. Meanwhile, stick with a torrent client. ☢ Kieff | Talk 08:58, 10 October 2005 (UTC)
Get Firefox! purplefeltangel (talk)(contribs) 20:59, 9 October 2005 (UTC)
Firefox doesn't support integrated BitTorrent at all, and probably won't for a long time. I'm using it now anyway though. --pile0nadestalk | contribs 22:07, 9 October 2005 (UTC)
Sorry, I just hate Opera. :D purplefeltangel (talk)(contribs) 23:23, 9 October 2005 (UTC)
Why? Jealous? ^^ ☢ Kieff | Talk 08:55, 10 October 2005 (UTC)
Now, now boys, no fighting. We all know Firefox is better, so we shouldn't let this get ugly :P gkhan 15:59, 10 October 2005 (UTC)
Based on what you think it's better? Certainly not on security, speed, resource management, user interface, functionality and features, I'm sure. ;) ☢ Kieff | Talk 06:13, 11 October 2005 (UTC)

sending/receiving faxes online[edit]

Hi I was wondering if there was a free service or a very cheap one that would enable me to send a receive faxes online. I would prefer something that would let me goto "file" and then "print" and let me send a fax that way, similar to printing, but would ask me what phone number I would like to send it to. Something similar to efax.com. I used to use that, but now they want money.


Thanks

You can send (but not receive) for free via The Phone Company if the number you want to send to is covered by them. It works via email or their web site, not by "printing" the fax to them, but it is free. -- AJR | Talk 22:46, 9 October 2005 (UTC)
Actually, there are some clients for TPC that do act as print drivers. --WhiteDragon 18:52, 11 October 2005 (UTC)
If you just want to send a fax from your computer then all you need is a fax modem. Most of these work by having you print your document using a special print driver, then dialling another fax machine and sending just like a normal fax machine. That's not really "sending a fax online" though, as it doesn't involve the internet.. To do that you'll need some kind of web-to-fax or email-to-fax gateway service such as the one AJR named above. Typically with these kinds of services you get what you pay for.. Free ones are often limited in some way such as the amount you can send per week, or appending messages to the end of your fax. Noodhoog 14:21, 11 October 2005 (UTC)
For receiving faxes, [34] has a free account, where you get a fax number (but can't specify the area code) for a limited number of faxes that get delivered to your email inbox. --WhiteDragon 18:52, 11 October 2005 (UTC)
All the KDE applications have a "Send to fax" option in the printing menus, which I think answers the first question. Assuming you have an unused modem connected to your computer (and to a phone line), that will send the fax.
If you have a Mac, it's very similar. In the print menu, select "Fax PDF" instead of choosing a printer. To receive, tick "receive faxes on this computer" in the "Print and fax" settings window, and specify where to save them.
It should be similar for Windows, but someone else will have to tell you where the options are. Ojw 20:38, 11 October 2005 (UTC)

energy from the seatemperature[edit]

I recently heard that an average hurricane unleashes an amount of energy equal to five times the worldwide annual energy consumption of humans (still can't believe it - did I misunderstand?). I understand that that energy comes from the temperature difference between the water and the air. So naturally I thought if this energy could be harnessed. There are two obvious advantages, one being the energy source and the other being the prevention of hurricanes. The Ocean thermal energy conversion article is about temperature differences between different parts of the water, which is something different (or is it really?). Would something like this be plausible? DirkvdM 18:12, 9 October 2005 (UTC)

I've thought about this topic myself. There is a great potential there, but actually developing an efficient mechanism to exchange heat between the air and water is quite a difficult problem. The main issue is that the temp diff is so gradual and spread out over such a wide area. If we had a thousand degree temp differential of two dense fluids right next to each other, it would be easy to generate energy from this, but a 5 degree difference over two fluids (one of which is a sparse gas) more distant from each other is another matter. But, if you can think of such a device, your fortune will be made ! StuRat 20:36, 9 October 2005 (UTC)
The surface water could also be cooled by using cooler water from below the area which receives most of the thermal energy from the Sun, but this is also impractical under today's technology. Perhaps instead of waiting until the water is over-warmed, a more proactive approach is in order. Large areas of the ocean could be covered by solar collection panels, to prevent the water from becoming warm, but the low efficiency and high cost of solar cells makes this scheme impractical, too. A newer technology, like genetically engineered microbes that live in seawater tanks, extract sunlight energy by photosynthesis, and release methane gas as a waste product (which we would harness for energy). might be a better way to go. StuRat 21:08, 9 October 2005 (UTC)
Better make those microbes sterile -- I'd hate to imagine what'd happen if they were released into the real ocean and then started reproducing… Garrett Albright 18:19, 10 October 2005 (UTC)

The energy from the sun that warms the oceans is currently used to power vast ocean curents that help equalize Earth's temperatures, create hurricanes and other weather patternes, and cause vast amounts of fresh water to be distributed over the face of the earth in the form of rain and snow. The energy is not going to waste. WAS 4.250 22:27, 10 October 2005 (UTC)

There's a theory about dropping ice crystals or other chemicals from aircraft into the tropical storm from above. The crystals or other chemicals then interact with the wet air to have a chemical reaction to transfer energy to or from the storm. The idea is to try to steer it away from land. There's been experiments with this. I do not know the outcome.
There's places in the world where they get energy from the sea by tapping the tides. Consider an estuary that comes about because of a major river and how the coast to the sides of it happen to be topographically. As the tide comes in, it gets squashed sideways, so as to be quite high. Well put a dam there that drives turbines for electricity, then when the tide goes out, have the turbines going in the other direction.
Fresh water can also be got from sea water through desalination (spelling?).
There's a school of thought that if we humans do a lot of that, it could mess up the natural temperature ranges of the sea, thus impacting the ocean currents, and doing real damage. AlMac|(talk) 06:26, 11 October 2005 (UTC)

Not sure quite how relevant this is, but there's a guy developing a system to generate power from artificial tornadoes - The Economist recently ran an article on it Noodhoog 14:30, 11 October 2005 (UTC)

GASES[edit]

HELLO JUST GOT A QUICK QUESTION ABOUT GASES, WHAT GAS DISSOLVES IN WATER AND WHY82.26.64.128 18:55, 9 October 2005 (UTC)

Lots of gases dissolve in water. Carbon Dioxide for example. But don't ask homework questions here and turn off your CAPS LOCK. smurrayinchester(User), (Talk) 19:58, 9 October 2005 (UTC)

what is the SI unit used to measure time?[edit]

You'll be wanting to look at our article on SI. TenOfAllTrades(talk) 21:30, 9 October 2005 (UTC)

also Time#Present day standards --JWSchmidt 21:32, 9 October 2005 (UTC)

It will only take you a second to find the answer there. StuRat 21:38, 9 October 2005 (UTC)

Is it just me or is Mother Nature really pissed off?[edit]

  • Three hurricanes went across Florida last year.
  • Mt. St. Helens threatened to erupt.
  • Thousands were killed by the Indian Ocean earthquake and subsequent tsunamis.
  • Hurricanes Katrina and Rita tore up the Southern U.S. and areas south of that.
  • A couple thousand people were killed in Guatemala due to a mudslide because of Hurricane Stan. They'll probably declare one town a mass grave since the inhabitants are under 40' of mud.
  • And then there's the earthquake that hit Pakistan/India/Afghanistan with 20,000+ dead there too.
  • I think I'm forgetting something from last year but I can't recall just what.

So, is it just me or does this seem like a lot of death, destruction, and mayhem caused by natural disasters for just two years? Can anyone point out another relatively short period of time where a series of events have taken place that have done similar damage? I realize that The Black Plague or possibly the devestation of Pompeii killed more but they had just one root cause. These events have had different root causes and have been more spread out. Or if I'm being naive, just let me know... :) Dismas|(talk) 05:42, 10 October 2005 (UTC)

The exponential growth of global warming contributes to many of these disasters one way or another. --Ballchef 06:21, 10 October 2005 (UTC)
The whole global warming discussion is controversial, and I am not sure about the mechanism where is contributes to earthquakes.

Also, population pressure forces large numbers of people to live in areas subject to earthquakes, mudslides, hurricanes etc and poverty means they can't afford to build earthquake-proof buildings or flood defences. And the global media strengthens the recency illusion. You might want to see our list of disasters and the pages linked from there. Gdr 07:34, 10 October 2005 (UTC)

After edit conflict:
I don't know how many got killed in Pompei, but it can't have been too many because the population then was so much smaller than it is today that it must have been a small town by today's standards. And the death toll of the black death was immense, but the Spanish flu killed between 25 and 50 million people in one year. Which is one cause of the great death tolls. There are just more people to get killed. Another thing is that we hear more these days because the media are more present and more info on international affairs. Still, they're regionally biased. Look at your list. Out of the 9 disasters you mention 6 are in the US. Let me guess. You're from the US. Which is why those disasters get more attention than they deserve (also in Europe). Take Katrina. On a worldwide scale that was peanuts. That sort of thing happens regularly in Bangladesh.
About the overall picture, I really don't know if there have been many more disasters in the lat few years, but either the increase would have to be enormous (say ten times normal) or there would have to be a trend over a longer period to draw any statistically valid conclusion that something is going on.
Ballchef says many of these things can be attributed to global warming. In the cased of the Asia tsunami, St Helen's and the earthquakes, there's no link. But there are reports that hurricanes are becoming more frequent and occurring in places where they shouldn't occur or not at that time of year. But that's also nothing compared to the disaster we're facing with the shift in climate zones due to global warming. Crops will no longer grow where they used to. Which will lead to mass starvation. Luckily, not so much for us, more in poor countries. But it will wreck our economies as well. So we will just be less filthy rich.
In the nearer future, we can expect a pandemic of the chicken flu. That's not a question of if but of when. And it's going to be soon. With an increased population compared to the Spanish Flu it could kill more. Let's hope that the increase in technological knowledge will give us a better chance to prevent that. DirkvdM 07:48, 10 October 2005 (UTC)
Shut up you and your science!!! It's the end times coming!!!
Uhm, seriously, this was due to happen. Like it has been mentioned, global warming and super population just makes it all more tragical. Besides that, estimatives about cyclic catastrophes put this particular decade (actually, this half-century) on range of several large ones. Scientists say that soon San Francisco and Los Angeles will suffer from a massive earthquake while a bunch of volcanoes erupt worldwide, and a gas explosion happens once again on the bottom of that lake in Africa. A huge piece of earth will also collapse on that other island I forgot the name, and that will create a ultra massive tsunami. Oh, and of course, the martians arrive. Bad luck, perhaps. ☢ Kieff | Talk 08:53, 10 October 2005 (UTC)
  1. An earlier generation thought AIDS was a terrible disaster.
  2. A later generation will think the use of WMD by terrorists is terrible.
  3. Don't forget super volcano under a major national park.
    1. and the aftermath of a giant rock from space hitting our planet ... we have the scientific know how to protect humans from what wiped out the Dinosaurs, but not the political will.
  4. How come the USA is so inept when it comes to fighting wild fires out west?
    Wildfires in the western US are a normal part of the ecology there, due the dry climate and frequent lightning storms. See our wildfire article for an explanation of why trying to put them out is a bad idea. Gdr 11:58, 10 October 2005 (UTC)
  5. Then there are serious consequences of the ozone hole in the Southern Hemisphere, which not get much press in the Northern.
  6. Global warming and Global cooling are on a long term cycle ... consider the Vikings crossed North Atlantic Ocean at same latitude as the Titanic but had no problem with ice bergs because the Vikings were in a period of global warming, and the Titanic in a period of global cooling.
    1. Albert Gore had a book on history of environmental changes which talked about the Year of no Summer in Europe that led to an agricultural calamity that was the forerunner to the Black Death.
  7. While Hurricane Katrina was a natural disaster, there was a lot of things that mankind failed to do in the mitigation of emergency planning that contributed to making the disaster much worse than it might have been otherwise.
    1. The National Hurricane Center, and other Weather Professionals have been tracking patterns for decades. They show that there are like 40-50 year cycles in frequency of tropical storms. An "inactive" cycle can still have a really bad one like Hurricane Andrew, so you always need to be prepared, especially in Florida, which seems to get more Hurricanes than the rest of the world combined. Right now we are in the early stages of an "active" cycle, meaning in the next 10 years or so they will get more frequent, which will include more of the very bad ones.
      1. The Army Corps of Engineers is using data from earlier "inactive" cycle, that says 1 chance in 500 per year, that New Orleans could be hit by a Hurricane worse than Category 3, so that's all we need to protect the city from.
      2. Millions of dollars came from the Federal government to pay to make the levees able to protect the city from a Category 3 Hurricane, but the local government found other more important things to spend that money on.
      3. Building a city below sea level seems foolish ... what's the practicality of rebuilding on higher land ... raising the land before the rebuilding
      4. Due to global warming, sea level world wide is rising slowly, so New Orleans is a precursor to what all coastal cities will be facing in the next 50 years. The vast majority of them do not have protection as "good" as New Orleans.
    2. Government knew from past Hurricanes, and US Census, that something like 1/3 of the population was too poor or disabled to voluntarily evacuate, plus there was a significant other minority that would never cooperate with a voluntary evacuation, choosing to ride out any storm because they did not understand the Category system, and also feared looters
    3. City of New Orleans had an evacuation plan, that they failed to implement
    4. Widespread Looting and Mayhem turns out to have been an Urban Legend mass produced by the News Media, that led to significant delays in getting help to New Orleans, and some ugly incidents against people trying to flee flooded areas
  8. The news media has a talent for painting every humanitarian disaster as the worst ever in history, which means that a lot of people do not believe it when it really is bad.

AlMac|(talk) 09:41, 10 October 2005 (UTC)

I don't want to put a downer on the previous upbeat answers but hang around until the next big comet impacts the Earth and wipes out 99% of life on earth. After many more big comet strikes on our planet, the Sun will eventually turn into a Red Giant and you can say goodbye to the world. That's if our solar system does't as some point get too close to a black hole and get swallowed. Actually I think that mother nature seems quite benign at the moment. Majts 09:48, 10 October 2005 (UTC)

SO... Does human population/development/existence have any effect of the frequency/size of earthwuakes, or is it all natural? --Ballchef 00:00, 11 October 2005 (UTC)

There is some speculation that the weight of oil deep down, then removed by oil drilling, can have an effect on the stability down there. AlMac|(talk) 03:44, 11 October 2005 (UTC)
I really doubt that the tectonic plates care much about the featherweight that is human civilisation crawling on its surface.--inksT 01:29, 11 October 2005 (UTC)
In the Netherlands we've got a problem with the ground sinking where gas has been pumped out, and that can lead to minor earthquakes. DirkvdM 17:48, 11 October 2005 (UTC)
When some part of our planet is unstable, can terrorists help trigger trouble, like perhaps setting of WMD in the side of a Volcano, letting the lava flow out there, and the change in pressure, perhaps trigger an eruption. Or is this speculation we not want to encourage? AlMac|(talk) 03:43, 11 October 2005 (UTC)
I'm sure that would work...but if I had such a WMD I'd stick it in downtown Manhattan for greatest effect. :) --inksT 06:05, 11 October 2005 (UTC)
This was also the theme of a James Bond film, although that's of course no guarantee that will work. But it sounded fairly plausible. DirkvdM 17:48, 11 October 2005 (UTC)
Scientologist! All you need to do is pile bodies 100-deep by a volcano, and trigger it with a nuclear weapon. Then all the dead bodies become Operating Thetans... Ojw 21:32, 15 October 2005 (UTC)
Geesh, given the diversity of all those folks (above) that are allowed to edit an encyclopedia there's no wonder about what makes this project so great. --hydnjo talk 01:19, 16 October 2005 (UTC)

Carbonic Acid[edit]

Please can anyone tell me what is the chemical mechanism for the formation of carbonic acid (H2CO3), from its constituents CO2 and H2O is? Thankyou, Ben

--163.1.209.120 07:34, 10 October 2005 (UTC)

  • I'm not sure how my answer disappeared, so I'll say it again. Carbon dioxide and water form a small amount of H2CO3 when CO2 dissolves into the water. - Mgm|(talk) 10:54, 10 October 2005 (UTC)
Under pressure (which is what soft drink maker do) more CO2 will dissolve.

Toxicity of cured epoxy[edit]

I've been sculpting with epoxy for a few weeks now and my cat just ate a tiny ball of epoxy (much less than 1 cm in diameter). The epoxy's been cured for a few days already.

I'm not sure how much of a hazard this can be to a cat. I'd suppose that cured epoxy is less dangerous (less reactive), but I don't know shit about toxicity of this substance when ingested, especially by an animal. Should I be very worried or what? ☢ Kieff | Talk 08:41, 10 October 2005 (UTC)

It says it's very toxic at the bottom of this page. Although if cured it *may* pass through the system without ingesting. Usual disclaimers: consult a vet and the epoxy packet for any warnings given. Majts 10:13, 10 October 2005 (UTC)

Actually, I just found the little ball in question behind the desk, so it's ok. :) ☢ Kieff | Talk 14:37, 10 October 2005 (UTC)

Orginal Investor In Both[edit]

Who was the orginal investor in both Microsoft and Apple Computer companies?

MANY THANKS Paul Autin, CSET Cantonment, Fl 32533-7510 [email address removed]

Please don't post your email address on the Reference Desk unless you want to receive spam. Until each company "went public," both Microsoft and Apple Computer were private companies owned by and invested in by their owners. See each respective article for more on each company's history. Garrett Albright 18:07, 10 October 2005 (UTC)

How much water would a person have to drink before it killed him?[edit]

Just curious. --Maxamegalon2000 17:32, 10 October 2005 (UTC)

The LD-50 of water is something huge - on the order of half your body-mass, I believe. Messy death, too, but very difficult to actually achieve - generally the body's reflexes kick in and stop you consuming more. It's a lot quicker by drowning! Shimgray | talk | 17:47, 10 October 2005 (UTC)
  • Leah Betts supposedly died from drinking too much water, but according to that article it was more due to drinking too much water in too little time (7 litres over 1.5 hours). --Bob Mellish 17:59, 10 October 2005 (UTC)

Drinking enough to cause seizures and unconsciousness (water intoxication) is not so rare. There are plenty of case reports in the medical literature, including a few with fatal outcomes. The amount to induce unconsciousness varies by body size, ambient conditions, and starting degree of hydration, and whether alcohol or various salts or sugars were in the water, but would be much smaller than half your body mass, more like 5-10 liters of pure water chugged in rapid succession for an adult. alteripse 18:04, 10 October 2005 (UTC)

There are many factors involved. It may vary, but in a person of low blood-electrolyte concentration, the loss of necessary electrolytes can cause cellular damage, especially in the muscles and vital regions of the brain. This dilution will complicate the body's normal physiological functions, which depend on many chemicals dispersed through the body. Another may be the enormous bloating. Too much water will raise blood volume and will increase blood pressure. That can cause further problems in the cardiovascular system, making it difficult for the heart to help the blood nourish and for the blood to nourish the body.--Screwball23 15 October 2005 7:59PM
Having poked around, it seems I was remembering "enough to start physically destroying cells", as opposed to "enough to cause shock and unconsciousness, then potential death". Shimgray | talk | 18:12, 10 October 2005 (UTC)

This site says the pledge at Chico State drank 5 gallons, but there were other factors involved as well. User:Zoe|(talk) 04:10, 13 October 2005 (UTC)

Pharmacy Compounding[edit]

Hi, I was wondering if there was a free web site that has compounding ingredients and recepies. I know there are pay sites, but they are very very expensive.

Thanks

same system call interface[edit]

Hi,

I am looking for the answer for the below question.

What are the advantages and disadvantages of using the same system call interface for manipulating both files and devices?

Thx

BK

--68.239.159.120 19:01, 10 October 2005 (UTC)

Is this question for your homework? Notinasnaid 19:10, 10 October 2005 (UTC)


Yes

You might like to note two things:

carat[edit]

what is the measuement called that can measure a carat that has the description of unit of weight for gemstones?

see Carat (mass). It probably answers your question . - Nunh-huh 02:56, 11 October 2005 (UTC)

Propagation speed of a tsunami wave[edit]

The propagation speed of a tsunami wave is , from what I have read , of the order of 200 to 500 km/h .

What are the factors which determine the actual speed ? Is there somewhere a description of an appropriate model which describes that wave ?

Any help will be appreciated , thank you .

There is a brief mention of the physics involved in a tsunami in our article about tsunamis (sp?).--inksT 22:04, 10 October 2005 (UTC)
If you're a genius, look at this article and the references gkhan 22:22, 10 October 2005 (UTC)
If hazy memory of first-year physics serves, the dominant factor controlling speed of propagation of a wave is the depth of the water - shallower water slows the wave. Shimgray | talk | 22:25, 10 October 2005 (UTC)
My understanding is the same volume of water in shallower water causes the wave to go higher, so far out in deep water, the wave might only be 5 feet or so high, then when it reaches the continental shelf it can go to 100 feet high. AlMac|(talk) 03:47, 11 October 2005 (UTC)

Frogs[edit]

Are African Clawed frogs labyrinth breathers? PLEASE HELP ME!

I've got no idea, personally, but have you looked at African clawed frog...? -- SCZenz 23:09, 10 October 2005 (UTC)

Ubuntu vs Suse[edit]

I have been using Mac PCs since I was about four and Windows 9x since I was six. (I'm fourteen now.) I am now a Windows XP user. I consider myself to be fairly proficient with using computers and not screwing anything up, and recently I have been looking into installing a Linux distro on my older computer. I'm leaning heavily towards Ubuntu because I know for sure it has a GUI (which, sorry, is a requirement for a newb like me), is customizable and is, so I hear, easy for newbies. However one of my friends insists that I should get Suse, because "Ubuntu is for people who know what they're doing" and "Suse comes with more programs." I find this to be rather dubious, but I would like a final answer on this one -- should I get Ubuntu or Suse, or some other distro entirely? Thanks. purplefeltangel (talk)(contribs) 21:18, 10 October 2005 (UTC)

Practically every Linux distribution designed for desktop use has a GUI, so there's no worry there. Similarly, programs tend to be available for any, since all a distribution really is in the end is a bundling-up of stuff. Nothing there to prevent someone from adding in more stuff later! Both SuSE and Ubuntu come with a great deal of stuff; since Ubuntu can use Debian packages out of the box, I think it wins in total amount of prepackaged software available. (SuSE uses RPM, like Red Hat, but they're not necessarily Red Hat compatible, while Ubuntu is explicitly Debian-compatible.) To be honest, a complete beginner won't probably notice the per-distribution differences because they are tiny compared to the differences between Linux and Windows. Both SuSE and Ubuntu offer "live CDs"; that you can boot and run without having to install anything permanently; you might try grabbing both and seeing if one or the other seems to appeal to you more. — 15pxmendel 23:21, 10 October 2005 (UTC)
Thank you! purplefeltangel (talk)(contribs) 00:12, 11 October 2005 (UTC)

Extra question: On the Ubuntu website, where can you get LiveCDs? purplefeltangel (talk)(contribs) 00:25, 11 October 2005 (UTC)

Just follow the download link, then select the release and country. For example, the page for US downloads of the Breezy Badger release candidate [35] is neatly divided into sections for install CD, live CD and combo DVD. The file you will download has a name in the form ubuntu-<version>-live-<architecture>.iso, for example ubuntu-5.10-rc-live-i386.iso.-gadfium 03:04, 11 October 2005 (UTC)
You can also have CDs posted to you for free [36]. I think everyone's waiting for the next version, due out this month. Ojw 11:46, 11 October 2005 (UTC)

I upgraded from SuSE 9 to SuSE 10 this weekend and I must say that I'm very pleased with it. SuSE 10 support all my exotic hadware such as wireless LAN, bluetooth and touchpad. However, I sometimes have problems installing software through RPM packages since they are usually build for Red Hat/Fedore, this might be better under Ubuntu since it is compatible with Debian. --R.Koot 16:02, 11 October 2005 (UTC)

New version of Ubutntu was released today. Ojw 18:53, 13 October 2005 (UTC)
Ubuntu is built on Debian. After getting comfortable with Ubuntu, try Debian itself. Debian is command-line--based and is used mainly by experts. When you want to run server software (web server, FTP server, etc.), use Debian —Masatran 07:54, 16 October 2005 (UTC)

A Sunny Question[edit]

Is there a link between the amount of matter leaving the sun and the strength of the sun's gravitional field? Like if hot air rises cold air rushes in to fill the space left behind? --Eye 21:50, 10 October 2005 (UTC)

I'll take a crack on answering this, although my knowledge of physics in the real world is somewhat limited, as noted in an above question :P. No, they are not (directly) related. The strength of the suns gravitational field is related to the sun's mass, nothing else. When you say matter leaving the sun, I am not quite certain what you mean. What leaves the sun is not matter, but light, and light is not matter (there might be particles leaving the sun in some sort of process that I am unaware of, but not enough to influence the mass of the sun in any way that matters). You mention cold and hot air, the thing is that outside the sun there is a near-perfect vacuum, so no convection occurs. gkhan 22:12, 10 October 2005 (UTC)
The solar wind is matter which leaves the Sun, but not because of convection. See the article for details. Matter also leaves the Sun by conversion into energy during nuclear fusion of hydrogen into helium. StuRat 23:05, 10 October 2005 (UTC)

Proper care after hip fracture.[edit]

I just noticed this question comes from the same address as the next, on anticoagulation, so they are probably related. One of the big risks after a hip fracture comes from prolonged immobilization - this is one reason for anticoagulation. You might want to look at the links from our hip fracture article. The answer to your question depends on the type of fracture, whether surgery has been performed or is contemplated, and to some extent on the health and age of the person with the fracture. Surgery and rehabilitation are common treatments for hip fracture. - Nunh-huh 02:55, 11 October 2005 (UTC)

How does coumdin work to thin the blood?[edit]

In short: "thinning the blood" means making it less likely to clot (it doesn't change the blood's viscosity). Coumadin, also called warfarin, does this by reducing the amount of clotting factors in the blood, by reducing the amount of certain clotting factors produced by the liver (namely, the vitamin-K dependent factors). Because it takes a few days for this reduction of clotting factor production to show up (when coumadin is taken in therapeutic doses), coumadin isn't useful in situations where blood must be "thinned" quickly: often heparin is started for short term anticoagulation and continued until coumadin's effects have been established. Our articles should tell you more, or you can ask any unanswered questions here if you like. You might also want to take a look at anticoagulant, and at antiplatelet drugs (which work to prevent clot formation, and are not blood thinners, which work by anticoagulation). - Nunh-huh 02:49, 11 October 2005 (UTC)

Are there any open source Internet Explorer shells?[edit]

I am looking for a working GPL'd IE shell, as some of its code may be useful for this Firefox plugin/extension. (current extension version is here) (also posted in Talk:Internet Explorer shell) --pile0nadestalk | contribs 03:24, 11 October 2005 (UTC)

I may be mistaken, but I believe all that's needed for the most basic shell is loading shdocvw.dll. It contains everything you need to make a WebBrowser control, and includes all the basic functions you'll need. --Pidgeot (t) (c) (e) 19:05, 13 October 2005 (UTC)

aiming at the bowl[edit]

Why is it hard to aim one's urine when one has a erection or semi erection? Even when one's penis is aimed at the right spot of the toilet bowl, the flow of urine doesn't hit where it should. What is causing this interference?

Warning, you may have damaged an important part of your anatomy through ignorance, and better check with a Medical Doctor for health guidance. There is a valve in there some place to control whether your penis delivers urine, or sperm. You do not want to be delivering urine to your future wife do you? You want to deliver sperm. The valve controls which is delivered, but you may have a damaged valve. (I not know the technical anatomy terminology.) AlMac|(talk) 03:53, 11 October 2005 (UTC)

Yeowch! Be careful. There is a valve that separates to allow semen through and one that allows the urine to flow through. If you have an erection, the valve is shifted for the semen, leaving the urine valve closed for the moment. DO NOT any point try to direct your penis downward because that will NOT stop the erection and change the valve. The valve only changes when it is flaccid and it does this naturally. If you move your penis beyond a certain angle downward, or in any direction for that matter, you risk causing a penile fracture. --Screwball23 15 October 2005 8:11PM
  • I'm not sure the question is relevant to your answer. Nothing's wrong with his valve (or whatever it is); he just wonders why it's hard to pee with a PHO (sometimes known as a Morning Glory). This is original research, but it seems to me that the average male penis changes in several ways when erect; I imagine the engorged portions of the penis are shaping the urethra and adjacent domains in a somewhat different way than the usual. --jpgordon∇∆∇∆ 04:48, 11 October 2005 (UTC)
    • I have some news, for you, Mister! Your aim is not so hot when you're flaccid! - Your Mom.
      • (rimshot) --jpgordon∇∆∇∆ 06:08, 11 October 2005 (UTC)
        • Thanks for the concern Almac, but I do not have a damaged valve. And Mum, I always wipe the seat when I miss. Thanks JPgordon, you seem to make sense, but what does PHO stand for?
          • Piss Hard On. I guess there isn't much need for an article on it (though if someone wanted to do an article on nocturnal erections, it could be vaguely interesting.) And Mom is sure mean. --jpgordon∇∆∇∆ 17:29, 11 October 2005 (UTC)
            • The semi-erection one could cope with, but a full? The only way I'd hit the target under such circumstances would be if the toilet were installed in the ceiling. Unless it were out of doors, in which case I would quite like the challenge of arcing it over a hedge into the given target area. Provided it were a windless day, of course. --bodnotbod 01:27, 13 October 2005 (UTC)

Sewerage into Power[edit]

I understand that researchers at Pennsylvania State University have found a way to use bacteria to generate power with sewerage. This is referenced here. As a student living on limited means in Canberra, Australia, how would I get the details of the research?

Try your local library- most public libaries in big Australian cities have subscriptions to New Sceintist.--nixie 05:15, 11 October 2005 (UTC)

God, I love how the concept of "library" outside this city I live is so utopically true. I need to leave this place, knowledge awaits. ☢ Kieff | Talk 05:24, 11 October 2005 (UTC)
  • As a Canberran myself, the ACT Public Library Service would almost certainly have New Scientist and the National Library of Australia certainly would. Further, if you go to the ACT Public Library Service website with a valid library card you can use a wide variety of online services see [37]. These include Academic Search Premier database containing access to 4,650 publications including more than 3,600 peer reviewed publications and the Marshall Cavendish Science Reference Centre. Finally, if you went to either a public library or especially the National Library, a public librarian should be able to find what you want. Capitalistroadster 05:39, 11 October 2005 (UTC)

See what I mean? Damn, I'd be lucky if my library had today's local newspaper ☢ Kieff | Talk 06:09, 11 October 2005 (UTC)

Even small towns have book stores and if they not carry the magazine or whatever that interests you, they will be happy to order for you. AlMac|(talk) 06:34, 11 October 2005 (UTC)
Yeah, we have book stores alright. But that's not how it works, not in Brazil or at least not this city. I asked a few places to get me these books ("My Inventions" by Nikola Tesla and the complete works of Edgar Allan Poe in the original english), that are published in São Paulo, but they said they couldn't do it, that I'd have to order from another city, even state. ☢ Kieff | Talk 07:42, 11 October 2005 (UTC)

Sorry, you misunderstand me. I have the particular New Scientist Magazine, but the article (like most in New Scientist) merely gives the general idea of the research. I have searched the NLA, the basic ACTLS, and have not found it. What journals would carry the detailed information?

School or university student?--Commander Keane 13:14, 11 October 2005 (UTC)
Here's the guy's webpage, and here's some links to his publications. --Robert Merkel 13:32, 11 October 2005 (UTC)
Thanks, that is very useful.
User:Kieff may wish to post a separate question here asking where there are places to order books, like amazon.com, that are happy to sell books and magazines to people in countries and cities in a relative dark ages of publishing distribution literacy. AlMac|(talk) 20:50, 11 October 2005 (UTC)
Bah! I'd be buying online if I could afford that. For example, the aforementioned Poe book would cost 80 reais from amazon. That's raping my pocket. ☢ Kieff | Talk 12:57, 12 October 2005 (UTC)

Visibility of stars on Moon landing[edit]

Hello.Why are no stars visable on pictures or film of the moon landings.

  • The Apollo moon landing hoax accusations article provides an explanation namely "There are also no stars seen in Space Shuttle, Mir, International Space Station and Earth observation photos. Cameras used for imaging these things are set for quick shutter speeds in order to prevent overexposing the film for the brightly lit daylight scenes. The dim light of the stars simply does not have a chance to expose the film. (This effect can be demonstrated on earth by taking a picture of the night sky with exposure settings for a bright sunny day. Science fiction movies and television shows do confuse this issue by depicting stars as visible in space under all lighting conditions.)" Capitalistroadster 07:27, 11 October 2005 (UTC)
    • ...which is actually a silly way of phrasing it. Of course sci fi films show stars in space, just as they ought to: stars are visible in space by th human eye. The movie experience is supposed to replicate you being there, and so replicate the vision of the human eye, not the limitations of film. That aside, Capitalistroadster is right — you don't see the stars because they're taking their exposure readings off that great big white thing. If they took a picture on the moon in which you could see the stars, the moon itself would be horribly over-exposed. — Asbestos | Talk (RFC) 16:25, 11 October 2005 (UTC)

Eyes have similar limitations, that's why we don't see stars during the day, or in brightly lit cities at night, they are drowned out by the light nearby. This is because we reduce the amount of light let into our eyes, which means the dim light from stars doesn't enter the eye in sufficient quantities to be visible. StuRat 23:11, 11 October 2005 (UTC)

information technology[edit]

what are the benefits and opportunities of information technology?

Is this, by any chance, a homework question?
Benefits of IT... like an awesome site where you have the opportunity to get smart people to help you with answers to tough questions... but not homework--Jmeden2000 14:22, 11 October 2005 (UTC)
Turn it around. What would modern business be like if there were no computers, because they had not been invented yet.
  • A heck of a lot more people would have jobs that had not been automated out of business.
  • Prices would be extremely high because we not have all the innovations from the computer revolution.
  • Life would be much more miserable for poor people and the downtrodden around the world.
  • See if you can find books about what life was like for ordinary people and for corporations like 50-75 years ago and ask how much of that was different because they did not have what we take for granted.

AlMac|(talk) 02:05, 12 October 2005 (UTC)

citrusjuices[edit]

What is the content in apple, lemon and orange juice?

^^^^Monica

An apple isn't a citrus but in general, all fruit juices will have mostly water, a fair amount of sugar (probably mostly fructose), some flavor compounds, some flavonoids, and some vitamins usually including vitamin C. Citrus juices as the citrus article says will have a fair amount of citric acid. Our flavor article has a tiny bit of info. Ávila 15:48, 11 October 2005 (UTC)

Coin rolling[edit]

I have always wondered why is it almost impossible to balance a stationary coin on its edge, whereas if you throw it, it almost seems to want to roll it on its edge? Similarly it's virtually impossible to balance on a stationary bicycle... Shantavira 15:25, 11 October 2005 (UTC)

Have a look at gyroscope; the principles are the same. Briefly, it's all about conservation of the angular momentum of the rotating coin or bicycle wheel, but I don't want to go into more explanation than that here. TenOfAllTrades(talk) 15:31, 11 October 2005 (UTC)
Although it is easier to keep a moving coin on its smaller surface at a higher velocity, as TenOfAllTrades explained, simpler reasons are also at work. The coin is most likely more heavy on one side and has uneven friction on both the table, its surface, and probably, a minute off-level relationship with the ground and gravitational forces.

Of course, those small forces are very little compared to the conservation of angular momentum. A unicyclist will much more easily maintain balance with constant movement than a bicycle rider at a slower speed, albeit with a larger surface area.--Screwball23 15 October 2005 8:23PM

Code Coverage Standards[edit]

What are the industry standards in percentage for Code Coverage a software? &&&Surya

This is about Software testing? Ojw 20:14, 11 October 2005 (UTC)

Learning VB.Net[edit]

How easy would it be to learn Visual Basic .NET from a knowledge of Visual Basic and Java? — Asbestos | Talk (RFC) 16:03, 11 October 2005 (UTC)

I'd say that should be a good history for learning VB.NET. Syntactically, VB.NET is (of course) very similar to Visual Basic, but it uses a large built-in class library (the .NET framework), which is in some ways analogous to the Java standard libraries. VB.NET is also truly object-oriented in the same sense as Java, which is not really true of Visual Basic. Your VB and Java experience should allow you to pick up the basics of VB.NET quite easily. It will take some time, however, to gain familiarity with the ins and outs of the library, but it's pretty easy to find what you need in MSDN. —Caesura(t) 18:24, 11 October 2005 (UTC)

Technology abuse[edit]

What types of tech abuse are there? If you can answer that would be great, I can't find any thing on Wikipedia. : ( --DB Master 16:41, 11 October 2005 (UTC)

Nuclear bombs? (Or any type of bomb for that matter.) Pretty much any technology can be abused. The question is pretty vague. DirkvdM 18:07, 11 October 2005 (UTC)
most any weapon can be abused, such as hand guns and other small arms. We can argue whether war qualifies as abuse. AlMac|(talk) 20:55, 11 October 2005 (UTC)
We could? DirkvdM 05:03, 12 October 2005 (UTC)
electrodes to the scrotum? Majts 20:10, 11 October 2005 (UTC)
most computer users are somewhat familiar with a panorama of spam malware phishing computer viruses identity theft the list seems endless with more stuff constantly being added, and it is all tech abuse. AlMac|(talk) 20:54, 11 October 2005 (UTC)
  • The word abuse implies there are necessarily correct ways to use technology (i.e. I can only "abuse" an e-mail program if I use it in a way for which it was not intended). Tied to the question of technology abuse would be whether or not technologies have inherent purposes, and if so, to figure out how to talk about them. Is a technology's "purpose" defined by who creates it? What is the "right" way to use a technology? Controversial technologies — of which handguns are a good example — bring out this distinction well. Is there a "right" way to use a handgun? What is it? Are there "wrong" ways? What does this mean? Are all "wrong" ways "abuse"? (i.e., what if you used a handgun as a hammer, to set a nail? That would surely be against the intended use of the "gun" by the creator of it or in the minds of most people using it, but would it count as "abuse"?) --Fastfission 21:08, 11 October 2005 (UTC)
I wanted to write that! (so why didn't I?) I suppose that's what AlMac meant, that war might not be abuse of technology as long as the technology is intended for war. DirkvdM 05:03, 12 October 2005 (UTC)

I sorta meant computer wise. I shoulda put that in the question. If you could answer with the new information that would be great : )--DB Master 17:34, 12 October 2005 (UTC)


Try this DB Master. http://en.wikipedia.org/wiki/Malware look at everything. I think thats what you want. I learned what i know from that. Hope this helps Does anyone know some of the punishments for these crims? Like making "dialers, rook kits" and such. Lordned 17:43, 12 October 2005 (UTC)

The typical punishment is a few years in jail, followed by a good paying job working for some company that thinks the way to get ahead is by hiring computer abuse felons. That's the people who get caught, most do not. I think the best punishment was the guy who got millions of dollwars from computer swindling, stashed the money with a confederate while he was in jail, then when got out found that his confederate had absconded with the millions, and he was faced with the income tax authorities expecting him to pay taxes on the ill gotten gains. AlMac|(talk) 18:49, 15 October 2005 (UTC)

Leptin[edit]

I would like to know how to increase Leptin in the the body, through diet, or any other way, naturally. I have been trying to research leptin, and only come up with sites trying to sell me some thing. Only this site, so far has provided concrete information. I would appreciate anyones comments on this.

You can raise your leptin levels by gaining body fat. Leptin is produced by adipose tissue cells and secreted into the blood. Blood levels of leptin serve as a signal to the brain and other systems in the body indicating the amount of body fat. Fat people tend to have higher leptin levels than thin people. alteripse 17:29, 11 October 2005 (UTC)

  • WHy would you want to do that. Leptin appears important in regulating several processes and levels of other chemicals. Increasing your leptin levels drastically might cause things to get off-balance. - Mgm|(talk) 22:04, 11 October 2005 (UTC)
    • I assume you are addressing our anonymous inquirer. I wondered the same thing. I might venture a guess that what he really wants to know is whether there is a way to do it without getting fatter, but I left this answer to teach him to formulate his questions more precisely. alteripse 23:37, 11 October 2005 (UTC)
  • Some medical studies suggest that smoking reduces leptin levels. If you currently smoke, you can possibly increase your leptin levels by not smoking. PubMed --JWSchmidt 00:39, 16 October 2005 (UTC)

Alien water supply[edit]

In one of my biology text books, desert rats are mentioned as being able to survive without directly taking in water, at they can recieve it though metablolism (as water is one of the products of respiration), my question is, that if this is the case, why is it always strained that when searching for life on other planets, we must first search for liquid water. If the desert rat can really obtain all its water by this means than surely life on other planets could use similar means, and their dependace would only be on hydrogen, oxygen and carbon being available. Maria Knott 18:54, 11 October 2005 (UTC)

The main focus is probably on finding planets with the right environmental conditions for liquid water, not the water itself. Cells' chemical reactions take place in an aqueous solution, so if the entire planet's temperature is above the boiling point of water they would be unable to function -- not to mention that proteins would be completely denatured. Similarly, biological chemical reactions would function extremely slowly or not at all below freezing.
If life on other planets is physically and chemically similar to life on earth, it would almost certainly not survive without liquid water. However, as you pointed out, this doesn't mean that surface water is a necessity. Also, since we don't know anything about extraterrestrial life, it may not use the same chemical mechanisms as life on Earth, in which all we can do is speculate. --David Wahler (talk) 21:04, 11 October 2005 (UTC)
There would have had to have been (?) water to start with, to let the species evolve. The only way that such water-based life could be present somewhere without there being any more 'free' water is that all the life has consumed all the water. Which, on second thought, is entirely possible. But, like David says, how can we know that ET needs water? Or is carbon based (as is often assumed). We don't even know what defines life here on Earth, let alone elsewhere. The USSR once developed a robot that was meant to detect life on other heavenly bodies. When they tested it on Earth it couldn't find any life....
In a way we cannot even speak of extraterrestrial life since our definition (if one day we find it) is tied to the Earth. Well, alright, if some'thing' steps out of a machine that just came falling from the sky and says 'Hi', we're probably dealing with life (and with at least some intelligence at that). But what are the chances that it will look or behave anything like us? Just look at the variation of life here on Earth (remember animals and plants are both Eukaryotes, which is just one of the three (or so) different lifeforms here on Earth - the others are Prokaryotes, Archaea and possibly Viruses, but we don't even know if those classify as life). Then think of all the different variations of circumstances on those Googillions of different planets out there (well, most likely, anyway).
"There's life, Jim, but not as we know it" :) DirkvdM 05:44, 12 October 2005 (UTC)


Cool, thanks for replies I can impress my biology teacher! Maria Knott 05:50, 14 October 2005 (UTC)

Average cardboard container, as in What is the color of...[edit]

I'm trying to determine––in CMYK terms, if anyone knows how the color of the average cardboard box/container, as in the context of color, is arrived at; what percentages of each pigment is used for a box to achieve its 'cardboard-ness'.

If anyone has the inside dope on this, I'd be very appreciative of it being made available to/for me and/or for others. Thank you for your time.

I think most cardboard containers do not have any pigment added, so are the color of the constituent materials, such as wood pulp and the chemicals used to process it, typically resulting in a gray or brown color. StuRat 22:55, 11 October 2005 (UTC)
I took a picture of a cardboard box and sampled a pixel which I thought "average". It has RGB values of 168, 138, 104, and a hex value of #A88A68. --Borbrav 05:53, 12 October 2005 (UTC)
Well, not all cardboard has the same colour. I did that too, and came up with 193, 146, 46. But the question was what the CMYK values are. In my case that would be 0, 24, 76, 24. For your values it's 0, 18, 38, 34. DirkvdM 06:18, 12 October 2005 (UTC)
Then again, what values yo get depends very much on the exposure. First of all, the light has to be neutral, which makes a scanner a better choice than a camera, unless you use (artificial) sunlight. That would influence the balance between the colours. But the 'common level' (or what should I call that?) depends on the amount of light. Ideally, you'd scan with a just-no-overexposed exposure and then straighten the bottom end of the histogram as well. DirkvdM 06:47, 12 October 2005 (UTC)

Srinking Sun[edit]

Is the sun getting smaller. Is it burning up?--Eye 19:38, 11 October 2005 (UTC)

Strictly speaking yes. It loses 4 million tons of mass every second. Don't worry though it still has at least 4000 million years of fuel left. See the article on sun Majts 20:07, 11 October 2005 (UTC)

And mass is energy?--Eye 20:23, 11 October 2005 (UTC)

As Albert Einstein originally theorized, mass has a potential for energy E=mc², so yes. For the original bit, though, "burning up" isn't fully correct; the sun undergoes nuclear fusion rather than combustion. — Lomn | Talk / RfC 20:32, 11 October 2005 (UTC)
As Bill Clinton once said it it depends on what you mean by is? I thought the questioner meant does mass=energy? To which the answer is no - unless you multiply it by a very big number -speed of light² Majts 20:53, 11 October 2005 (UTC)

Yes I know it's just that I can't spell nukleer fishon :-)--Eye 20:46, 11 October 2005 (UTC)

No, mass is definitely not energy. In simplest terms mass is the weight of the sun. nuclear fusionis the process that scientists describe as the sun burning. This is the process that converts the mass to energy (light & heat). It's therefore a very good thing that the sun gets a miniscule amount smaller every year or we would all be very dead due to no light or heat. Majts 20:48, 11 October 2005 (UTC)

Just to correct some of the above statements: mass and energy are two different forms of the same thing. Mass and energy are interchangable at a ratio of E = M *C^2, where E is energy, M is mass, and C is the speed of light. (So a small amount of matter produces an enormous amont of energy.) However, this matter to energy conversion only takes place in nuclear reactions (that is, reactions that modify the nucleus of an atom). The only place you can find such reactions are inside stars, inside nuclear reactors, or at ground-zero of an atomic-bomb blast. Energy-to-matter conversion is possible (I think), but off the top of my head, I cannot think of any situations where it occurs. →Raul654 21:17, 11 October 2005 (UTC)

To clarify - I did not state that mass is not a form of energy (&vice versa), I just stated that mass is not energy, which is true. For example, if the questioner asked is liquid water, ice? No, ice and liquid water are forms of the same thing but they are in a different state. Thanks for making it clear though. Majts 03:36, 12 October 2005 (UTC)


Energy-to-matter conversion happens in electromagnetic cascades, such as when a cosmic ray hits the upper atmosphere. Two electrons are pair produced from a photon that interacts with a bit of atmosphere. But yes, it's quite rare, because entropy always increases.
And yes, mass is a form of energy from the modern physicist's point of view. -- SCZenz 22:38, 11 October 2005 (UTC)
I assume you meant to say an electron and a positron being formed from the cosmic ray. --Borbrav 23:05, 11 October 2005 (UTC)
I did, yes; although "electron" is often used to refer to both negative electrons and positrons, it's probably confusing if I do that here, isn't it? -- SCZenz 23:17, 11 October 2005 (UTC)
Actually, while the Sun currently is getting a tiny, tiny bit smaller every year, it will eventually balloon up into a red giant, as a natural part of its life cycle. At that stage, it will be big enough to actually swallow Mercury, Venus, and Earth. So don't feel sorry for our poor little star, and don't forget your sunblock. ;) --Ashenai (talk) 23:18, 11 October 2005 (UTC)
Quite right, the question was not if the Sun is losing mass, but if it is getting smaller. The expansion to a red giant won't take place for another 5 billion years or so. But right now the Sun is fairly stable I believe. But I haven't a clue if it's getting smaller or bigger. I suppose that depends on what you define as the boundaries. For the Earth it's fairly simple if you leave out the atmosphere. And even then it's fairly well defined. But in the case of the Sun I can imagine that the play you have in determining the boundary is much bigger than the change in size, which would mean that in as far as we can define it's size it remains the same. Then again, I don't know, really :) . DirkvdM 06:31, 12 October 2005 (UTC)

This question prompted me to write a new article for Celeritas - I couln't believe there wasn't one already Majts 00:08, 12 October 2005 (UTC)

Let me do this question again...Is the amount of the sun getting less as a result of what it's doing? :-) --Eye 19:37, 12 October 2005 (UTC)

Yes, if you mean is it losing mass. "Getting less" could also mean the volume is reducing, and there are other factors that effect that, like the temperature, so it isn't necessarily losing volume as it loses mass. StuRat 23:46, 12 October 2005 (UTC)

Estrogen and Adrenalin[edit]

What are the effects of taking or producing high levels of estrogen? What are the effects of taking or producing high levels and low levels of adrenalin?

As for the estrogen, you may want to start your research at Sex reassignment surgery and Hormone replacement therapy (trans) and go from there. Dismas|(talk) 21:38, 11 October 2005 (UTC)

Dismas, 99.99% of people producing or taking "high levels" of estrogen around the world are females, not sex-changing males. Effects of estrogen depend on age, sex, and hormonal status of the person, how high the levels are, the duration of high levels, whether risk factors might be present that would amplify the effect, and whether a progestin is taken also. If you want something more specific, you will have to give us more to work with.

Effects of excess adrenaline depend primarily on how high, for how long, and whether the person has risk factors that would amplify effects. The most common effect of acute excess would be heart pounding, anxiety, tremor, pallor, sweating. Chronic excess occurs with pheochromocytoma and can include episodes of the acute symptoms, plus hypertension and eventually damage to heart muscle.

Effects of low adrenaline depend on whether deficiency occurs gradually or abruptly, and whether there are additional hormone deficiencies. In a healthy person, gradual loss of adrenal medullary function produces little in the way of symptoms, but for some people it can produce orthostatic hypotension in certain circumstances, or diabetic hypoglycemia in someone who takes insulin.

So what is your specific concern? (and don't tell me Dismas guessed it, or he gets to give you a more detailed answer). alteripse 23:29, 11 October 2005 (UTC)

I'm aware that the number of people taking it for sex-changes is small but the article on estrogen doesn't mention what would happen with "high levels". Although I hadn't read the articles I referenced, it would seem plausible that information about what the OP was looking for might be in the articles. Dismas|(talk) 03:09, 12 October 2005 (UTC)
No offense intended. As you saw from my finish, I agree that you might have the opportunity to say "I told you so." However I could think of a whole lot of other contexts as well. And I had no idea what "high" was intended to mean. High relative to what? If the inquirer is sincerely interested he/she can give us more details and I will try to come up with a more precise answer. alteripse 03:23, 12 October 2005 (UTC)
No offense taken or intended on my part either. And I agree, "high" is a relative term. I took it to mean "having effects above and beyond what would be demonstrated by someone with a "normal" amount of estrogen/adrenaline in their system for their gender". It seems to smell of homework to me though. It makes me think of some high school health class concentrating on hormones in the body since I can't think off hand of how else the two would be linked. Dismas|(talk) 04:29, 12 October 2005 (UTC)

This was not a high school question. Basically not even a board certified endocrinologist could fill in every space in the matrix I outlined without looking a few things up. Few medical students or non-endocrinologist physicians could fill half of the possibilities even given a couple of hours and a standard endocrine textbook. Give it a try and you will see what I mean.

I assume our inquirer has a specific situation in mind involving either self or a close acquaintance and with the details I might be able to better answer. alteripse 04:38, 12 October 2005 (UTC)

Invisible Spark[edit]

I am told that when we “see” a spark of electricity (or lightening) what we are seeing is electricity burning up air and/or water molecules. Is it possible to have a discharge of electricity that is invisible or does electricity always have to have a medium to travel through?--Eye 20:20, 11 October 2005 (UTC)

By "electricity", I assume you mean electrical current. Current is any flow of electrically charged particles. For example, current flowing through wires is the movement of electrons from one metal atom to the next. In the case of lightning bolts and sparks, the air's electrical resistance generates so much heat that the air molecules momentarily glow white-hot, just like in a light bulb. But a current can also flow through a cold conductor, or even a vacuum (see cathode rays), and in those cases you wouldn't see anything. --David Wahler (talk) 21:11, 11 October 2005 (UTC)
A fluorescent lamp also uses an electric current to make a gas light up, but it doesn't burn it up. DirkvdM 07:06, 12 October 2005 (UTC)
I think it's unlikely that the spark is "burning up" air or water vapour; arguably the production of ozone from oxygen could be counted as "burning oxygen" but I don't know that ozone production causes visible light. I think what you're seeing is the ionization and re-combination of oxygen and nitrogen. (And since sparks are common in dry air, I don't think water vapour is a big contributor.) Your last question is actually two unrelated questions: (a) Many discharges produce a wide range of electromagnetic wavelengths, right up into the radio spectrum, so perhaps there are contrived environments in which discharges produce no visible light; I don't really know. (b) Normally when we speak of an electrical flow we're talking about the exchange of electrons from one atom to its neighbour, whether smoothly in a conductor or chaotically in a spark; that requires a medium by definition. But an ion beam in a vacuum is also very much a flow of electricity. And induction can certainly happen through a vacuum, without even electrons passing; some would argue that it's not a "flow of elecricity" but it can certainly be part of an alternating current circuit. Sharkford 14:11, 12 October 2005 (UTC)

Losing its Shine[edit]

If the sun is losing mass, but not in the form of light because light is a massless partical, do solar eruptions and the solar wind account for all the mass being lost from the sun? --Eye 21:07, 11 October 2005 (UTC)

Also, some mass is changed into energy due to fusion of hydrogen into helium and other nuclear fusion reactions, according to Einstein's famous equation E = mc^2. StuRat 22:33, 11 October 2005 (UTC)
"Loose" is the opposite of "tight." "Lose" is the opposite of "win" (or "gain"). Now you know, and knowing is half the battle -- please tell your friends so that we can stop this abhorrent typo from perpetuating! Garrett Albright 20:05, 12 October 2005 (UTC)

vulcinism and evolution[edit]

Bold textItalic textI am very interested in volunology, and I watched both"supervolcanos"and "the Day the Earth Almost Died"(the {ermian extintion). So my quwstion is, which volcanic event-Basalt Floods(the Siberian Traps), or a supervolcanic eruption(like toba) has more of an effect on glbal climate and subsequent evolution?

The eruption that puts more ash into the atmosphere poses a greater global selection pressure on existing species. alteripse 23:34, 11 October 2005 (UTC)

Orange juice vs. apple juice[edit]

Why is it that, in a grocery store or market, orange juice is usually sold out of a cooler but apple juice (also, cranberry, grape, etc.) is generally kept on shelves? Would the orange juice spoil faster if it were on a shelf? Dismas|(talk) 21:34, 11 October 2005 (UTC)

What country are you in? Here in NZ, all juice is equal in the eyes of the retailers, and live peacefully together on shelves. Perhaps most people just want to drink OJ now, and so it's kept cool to encourage this?--inksT 21:39, 11 October 2005 (UTC)

Does NZ import its juice? That is probably the reason. We have dozens of varieties of OJ, with and without pulp, added calcium, added vitamins, preservatives, etc. Some are reconstituted from concentrate, many brag that they are not. I suspect the absence of preservatives and whether the product is reconstituted are the major things that determine need for refrigeration, not enticement to drink. alteripse 23:07, 11 October 2005 (UTC)

The U.S. Dismas|(talk) 23:22, 11 October 2005 (UTC)
Store apple juice is nearly all pasteurized and has preservatives added that allow it to be kept at room temperature. You can do that with orange juice too but there is a much bigger taste difference that the folks in NZ are apparently missing. alteripse 23:32, 11 October 2005 (UTC)
Can't say I pay much attention to store layout....there is some "premium" juice that costs five times more than petrol that only lives in the coolers, and it does claim to be "preservative free", "not from concentrate" and "no added sugar"....so I'd venture that you're right with regards to preservatives and freshness :) --inksT 23:58, 11 October 2005 (UTC)
Yeah. I'm not a picky man, but I can easily tell the difference between the stuff sold refrigerated and the stuff sold "on the shelf". (Incidentally, this was something I loved about the US - pints of good, fresh orange juice, for virtually nothing!). The real end of the scale is the stuff a housemate used to drink gallons of - the cheapest supermarket orange juice, would keep for about six months in the carton, but... ugh. Tasted like I was having heartburn. Shimgray | talk | 00:58, 12 October 2005 (UTC)
This was something I always disliked about Germany. The available juice was inferior to the refridgerated stuff in the states (the only more expensive alternative I saw was fresh squeezed offered by some restaurants), and in most homes I visited, orange juice was mixed with carbonated water. That of course didn't stop me from buying and drinking orange juice in what my neighbors clearly thought was inordinate quantities. — Laura Scudder | Talk 19:54, 12 October 2005 (UTC)

New Zealand imports most of it's orange juice- so the affordable stuff is the nasty reconstituted juice that can be kept at room temperature while unopened - fresh juice is available in most supermarkets but the price is premium. Juice from all fruits can be stored at room temperature if enough sugar, water and preservatives are added.--nixie 02:18, 12 October 2005 (UTC)

There are several ways to keep your OJ from spoiling:
  • Room temperature:
    • Irradiate it: I guess people don't like it but I can live with it.
    • Boil it: These are the juices on the shelves.
    • Dry it and make it into a powder form: No. This is not for me.
  • Rrefrigerator:
    • Rrefrigerate it and drink it in a matter of days: Currently the best choice in the U.S. and many other countries. (Freshly squeezed or reconstituted)
    • Add more sugar: Acceptible to some. But many people don't want their OJ sweetened.
    • Increase its acidity: Good for OJ. No good for apple juice.
  • Even colder:
    • Freeze it: Add less water to the OJ concentrate. I don't know if these paper cans are available outside the U.S.
If you add much sugar or acid and boil it, any OJ can be stored on a shelf. I just don't think anyone would like to drink such thing. Pulp is also an added ingridient. To a juice factory, they can always blend in required amount of pulp to their reconstituted juice easily.
How do you like frozen OJ? These 400% juices (1 part OJ + 3 parts of water) are usually made from concentrates. -- Toytoy 04:19, 13 October 2005 (UTC)

Calculating number of days[edit]

Is there an article or website that makes it easy to calculate the number of days between two dates from different years? NoSeptember 22:10, 11 October 2005 (UTC)

Lots of them! Ther are also programs that will convert between calendars. Google for "date calculator". One is at time and date.com - Nunh-huh 22:36, 11 October 2005 (UTC)

Sum of a squared general term[edit]

if tn=n squared what does Sn equal??Insert formula here

Anything you like. That's the whole point of using algebra to have the variables represent stuff. AlMac|(talk) 02:09, 12 October 2005 (UTC)
I think the question was asking for the formula \sum_{i=1}^N i^2=\frac{N(N+1)(2N+1)}{6}. To derive it, one would use the fact that the sum of an nth degree sequence is an (n+1) degree polynomial, and then proceed by mathematical induction or any of several other methods which are far nimbler but harder to explain. --Borbrav 05:41, 12 October 2005 (UTC)

Amount of work done[edit]

If there is a two-step process and two ways to go about doing it, would the way in which the first step has the bigger change in volume compared to the second, or would the way in which the second step has the bigger change in volume compared to the first, (but both arriving at the same final volume,) result in more work? Thanks
-- Миборовский U|T|C|E 00:15, 12 October 2005 (UTC)

In a system where there is no energy lost, the amount of work to get from one state to another should be equal, regardless of the path taken. Energy could be lost by things such as friction, however, then the energy loss would need to be investigated to determine which path would involve the most work. StuRat 02:19, 12 October 2005 (UTC)
OK, then let's say there are 2 cylinders with a piston, both having 10 L of air inside at 2 atm. Then the pressure is changed so that the volume becomes 20 L. Hess's law says same amount of work is done whether it's a multi-step reaction or single-step. But what if there are 2 kinds of multi-step reactions taking different pathways to reach the same result (volume)? Since work is not a state function, even though the end result is the same there should be some difference in work done?
-- Миборовский U|T|C|E 02:41, 12 October 2005 (UTC)
Exothermic reactions (which give off heat) will tend to lose energy as the heat energy will dissipate through the cylinder walls. Similarly endothermic reactions (which remove heat) tend to gain energy as the heat energy is "sucked out" of the environment. It's possible that a single reaction may generate or remove either more or less heat than two reactions, so experiment or chemistry would need to be used to determine which process has the greatest energy loss. Alternatively, you could just measure the amount of work in a more direct manner. StuRat 16:34, 12 October 2005 (UTC)

Who's this critter?[edit]

We were driving around the outskirts of Las Vegas when we noticed two of these deer (or whatever) in someone's yard. (There were also some rabbits, an emu, and heaven knows what else; it's not a native to the area, I wouldn't think.) Anyone have any idea what this is?

What sort of deer is this?

--jpgordon∇∆∇∆ 00:56, 12 October 2005 (UTC)

It looks very much like this one. Shantavira 11:22, 12 October 2005 (UTC)

It's either a Fallow deer or there is a Japanese version with a .....Japanese name.... which I can not remember --Eye 19:27, 12 October 2005 (UTC)

  • I venture that you are 100% correct. Thank you very much! --jpgordon∇∆∇∆ 16:58, 13 October 2005 (UTC)

radio communications[edit]

I had a problem operating my fm receiver

It can be tuned to 3 stations only. Once i noticed that at a certain place in my house i could hear one station whereas elsewhere in the house I would hear a different station..

Howz this possible??? and that too only in that specific position in the house..?

Perhaps you need to get a new aerial? In response to the second part, perhaps you live in an area where two radio stations are broadcasting at a similar frequency, thus interfering with each other as you move around. --Ballchef 06:09, 12 October 2005 (UTC)

People near my place who live close to the radio transmission tower used to pick up radio (not sure if FM/AM) through their kettles. Do you live close to the transmission tower?--Commander Keane 14:33, 12 October 2005 (UTC)
The short wavelength of FM transmissions sometimes means that interference patterns can be set up that vary over the size of a house. If there is a radio reflector nearby (potentially anything sizeable and metal) you may get a pattern where the reflection cancels out the unreflected signal at one point, but a few metres away doesn't cancel it. DJ Clayworth 19:03, 12 October 2005 (UTC)
On the same frequency? If so, sounds like capture to me (see Frequency modulation). Dysprosia 22:42, 12 October 2005 (UTC)

Well thanx for all ur replies. 1. I dont think that broadcasting of two stations on same frequency is permitted. The station I am supposed to hear is the national broadcaster and uses same frequency all over India.

2.Well if reflections are cancelled out by a potential radio reflector around then how come I hear a different station at the same frequency.

Broadcasting two stations on the same frequency may be permitted if the two transmitters are far away enough so they don't interfere with each other. Dysprosia 09:56, 13 October 2005 (UTC)
...which is why the allocation of the spectrum is done by legislative fiat in most countries. →Raul654 10:11, 13 October 2005 (UTC)

spanning trees[edit]

How many different spanning trees does a complete graph have?- anon

See Spanning tree (mathematics). It depends on the size and amount of interlinking between the points of the graph in question. - 131.211.51.34 08:17, 12 October 2005 (UTC)

Here's an easy way to answer questions like this with a minimum of thought: work out the values for some small cases and then look up the resulting sequence in the On-Line Encyclopedia of Integer Sequences. In this case (assuming the nodes are distinguishable), graphs with 1,2,3,4 nodes have 1,1,3,16 spanning trees respectively. Look up the sequence 1,1,3,16 in the OEIS and you'll find OEIS:A000272, "Number of spanning trees in complete graph K_n on n labeled nodes", together with the formula. Gdr 18:12, 12 October 2005 (UTC)

Alkaline batteries[edit]

Why is it that certain devices(e.g. Door chimes and an electronic sphygmomanometer) will only work with alkaline batteries even though carbon/zinc batteries are the same voltage? Don Pierson--88.106.22.42 10:32, 12 October 2005 (UTC)

As a battery decharges it's voltage reduces as well. So while a carbon/zoinc and alkaline battery both deliver 1.5 volts when fully charged, a carbon/zinc battery that is half empty might only deliver 1.2 volts, while a alkaline battery that is half empty will could still produce 1.4 volts. This shouldn't affect purely electical devices as much as mechanical ones. --R.Koot 22:01, 12 October 2005 (UTC)

revolving of planets[edit]

Why do all heavenly bodies rotate? --210.214.228.78 12:36, 12 October 2005 (UTC)

Hi! You may not be aware of the fact that you actually asked two different questions. The question title says "revolving of planets", but you're asking why planets rotate. A planet's rotation and revolution are quite different things, and the reasons for them are also different. Planets revolve around the Sun: the Earth takes about 365 days to make one such revolution. They also rotate around their axis; the Earth rotates once every 24 hours. Which phenomenon are you interested in? --Ashenai (talk) 12:40, 12 October 2005 (UTC)

A star's rotation and it's planets' rotation and revolution are all a result of the rotation of the gas and dust cloud from which they formed. As they contract into smaller spheres, any small rotation is greatly magnified by the conservation of angular momentum, which means smaller objects must spin faster to have the same amount of "spin energy". Similarly, galaxies increase their spin rate from the original gas and dust clouds from which they formed, as they contract. The question then arises as to why these systems had any spin initially. Any system with nonuniformly distributed matter travelling at various relative velocities will inevitably lead to cases of rotation. (For example, imagine two stars going straight toward each other with a slight offset that capture each other to become a rotating binary star system.) But, this in turn leads to the question of why matter isn't evenly distributed in the universe. We don't know the answer to that, yet. StuRat 16:51, 12 October 2005 (UTC)

Actually, it sort of depends on what you call rotation. The Moon rotates around its axis once every evolution around the Earth. So it's always got one side turned to the Earth, so from our point of view you could say it doesn't rotate (causing the Moon to have a so-called 'dark side', which is a misnomer for the side we don't get t see from here). To my surprise, in a previous thread here I learned that this eventually happens to all heavenly bodies, so even the Earth will (given enough time) have it's rotation slowed down to once every 365 days (provided, of course, we stick to the length of a day and don't keep om defining it as one rotation of the Earth). So then one side of the Earth will be constantly facing the Sun. But then that may take longer than 5 billion years, when the Sun will consume the Earth. DirkvdM 18:41, 12 October 2005 (UTC)
This phenomenon is called Tidal lock. - Cobra Ky Flag of the United States.svg (talk, contribs) 23:00, 12 October 2005 (UTC)

Thames Barrier[edit]

How many times was the Thames Barrier raised in 2004?

According to the Environment Agency's page here it was closed on two occasions - the 22nd of February, and the 12th of November. Noodhoog 14:52, 12 October 2005 (UTC)

Most efficient photosynthetic organisms[edit]

Although I suspect there are variables that would impact relative efficiencies (temperature, sunlight, water quantity, etc.), is any organism more efficient than another at converting carbon dioxide to oxygen? For example, does an oak tree convert more oxygen than a comparably sized vat of bacteria or vice-versa? How would one go about comparing the efficiencies of photosynthetic organisms? 207.71.24.174 16:40, 12 October 2005 (UTC)

I would think a single-celled organism, such as algea, would be the most efficient, as it lacks the support structures of a tree like a trunk, branches, and roots. This means every cell in the organism is devoted to photosynthesis, rather than only a small portion in the case of trees. To test them both, you could place a leaf (still connected to the tree) in a sealed bag transparent to visible and UV light, and collect it after 24 hours. Measurments could then be made of the gas amounts. Similarly, an equal mass of algea (added to water) could be left in a sealed transparent container for the same amount of time and similar measurements made. This would compare the photosynthesis efficiency by wieght of a leaf to algea. If you wanted to compare the photosythesis efficiency of the entire tree, you would also need to estimate the portion of the mass of the tree which is leaves, and multiply by that. I suppose you could uproot a small tree, weigh it, then remove it's leaves, and weigh them, to figure this out. I'd hate to see a tree killed if not needed, though (I must have some Druid blood in me, LOL). StuRat 17:22, 12 October 2005 (UTC)
How fast do algae reproduce? Being small, I can imagine that may be something like one generation per day. For which you'd have to compensate in the above experiment. But the question was about bacteria, and I'm sure that with them this would be a factor to take into account. By the way, not all bacteria photosynthesise. There's a huge variation in bacteria that live under all sorts of conditions, and based on that alone it's extremely likely there's some bacterium somewhere that will outdo any plant in this respect (or any other respect for that matter). DirkvdM 18:57, 12 October 2005 (UTC)
If the mass of the remaining algea is different (from the original mass) when it is strained off from the water, then an average mass could be found between the starting and ending mass. This shouldn't technically be a linear average, (Mi+Mf)/2, since the mass would be expected to increase geometrically, not linearly, but for small changes a linear average would be a close enough approximation. StuRat 14:10, 14 October 2005 (UTC)

science[edit]

How does pressure affect time

It doesn't. Time could affect pressure, however, as in the pressure inside a room with an explosive which is detonated. The pressure would definitely change with time in such a room. StuRat 17:35, 12 October 2005 (UTC)
Actually, time and pressure are completely independent. In the explosive example, pressure varies with time (it would be equally valid to say that time varies with pressure) but neither affects the other. — Lomn | Talk / RfC 18:01, 12 October 2005 (UTC)
I suppose we are looking at the word "affect" differently, I am taking it to mean "correlates with changes in" and you are taking it to mean "causes changes in...". I suppose a correlation can be taken in either direction, but it would be far more usual to say pressure is a function on time, P(t), than to say time is function of pressure, T(p). StuRat 20:29, 12 October 2005 (UTC)
Compressing a fluid would change its stress-energy tensor, which in turn would change the Einstein tensor, which describes the curvature of spacetime. So yes, pressure can affect time. Not by much, of course, for pressures usually encountered. --Trovatore 02:16, 13 October 2005 (UTC)
How about in a Black hole? Would it be wrong to say that pressure affects time in these circumstances? Majts 18:43, 12 October 2005 (UTC)
Acceleration changes time/space in a black hole (or elsewhere, for that matter), not pressure. DirkvdM 19:03, 12 October 2005 (UTC)
Vide supra. --Trovatore 02:16, 13 October 2005 (UTC)
I agree, life is absolutely super! :) DirkvdM 08:05, 13 October 2005 (UTC)
  • Pressure can have some small effects on a half life, though. --Bob Mellish 19:08, 12 October 2005 (UTC)
  • Geesh, I didn't know that. I'll go have a look (always somthin' to learn around here). Thanks, --hydnjo talk 01:09, 13 October 2005 (UTC)


See weather and barometer. In Spanish (or Portuguese) the word tiempo (or tempo) translates both to time and to weather. --User:Mdob | Talk 20:23, 17 October 2005 (UTC)

how much does it pay to work as a... and how long do you have to go to college for?[edit]

I was wondering how much on average it pays to work as a volcanologist? Also how long approximately do you have to go to school to get a degree in volcanology and can you go to a community college or do you have to go to a more extensive college? Thank you

-April S.

I don't think they do it for the money. --Eye 21:22, 12 October 2005 (UTC)

If you want to work as a research scientist in *any* field, you will need to do a four-year degree, and probably a graduate degree after that (so, all up, 7 or 8 years of post-secondary education). If you can possibly afford it, at least the four-year degree is a great thing to do anyway; college broadens the mind in so many ways other than just job-related stuff. Vulcanologists are employed by either the universities or the government, so you will earn a nice living but nowhere near what, say, a doctor or stockbroker would.
Ah, but with a minor 7 year investment, you could have your very own PHD in the field of vulcanology, which would make you what? A doctor of Vulcans, sorry, couldn't help myself--Armen Schrikken 01:29, 13 October 2005 (UTC)
However, by compensation, you get all the benefits of working as a research scientist (working with interesting, smart people, solving challenging problems that nobody has before, a fair bit of travel paid for by your job), plus a few more (your travel is often to wild, beautiful place and it's easier to impress members of the opposite sex with your job than a lot of other scientific jobs ;-) ). --Robert Merkel 21:50, 12 October 2005 (UTC)
Alas those places are not just a bit wild. What percentage of vulcanologists die of natural causes? :) DirkvdM 08:04, 13 October 2005 (UTC)
Well, a volcano is natural, sort of... Shimgray | talk | 12:23, 13 October 2005 (UTC)
I do not think that the major part of vulcanologists spends a lot of time near a vulcano crater (exacltly as an astophysic do not spends most of his/her time with his/her eyes looking at a telescope ... not to cite that he/she does not spend any time on the surface of another system star :-) ). About the wage I have seen some time ago a site with the average wage of several researcher job, but I do not remeber the site at the moment. AnyFile 16:33, 15 October 2005 (UTC)

intramedullary pins[edit]

How durable are intramedullary pins, fixated in the humerus bone? Will the pin eventually break down and have to be removed? Or will it break down and cause complications to the bone?

Today's technology utilizes titanium plates and pins which will, most likely, outlast the patient. --hydnjo talk 01:01, 13 October 2005 (UTC)

Scientists[edit]

Yes, they're the finest people on Earth. ☢ Kieff | Talk 01:23, 13 October 2005 (UTC)

Matlab, DLMREAD[edit]

Yes, this is homework, but I needed help with just one line of code, if any of you are familiar with matlab. Here was the question:

%% Write a matlab function called fileToStruct that takes in a file name
%% (with extension) and returns a structure array. The file can be either a
%% .xml file or a .txt file. 
%% If the file is a .xml file, it is an excel spreadsheet containing rows
%% and columns of data. You have to copy all the data from the spreadsheet
%% into a structure array. The first row in the excel file contains the
%% fieldnames of the fields of the structures. The second row onwards
%% contains data to be contained in the different structures of the
%% structure array. The value in each cell must be saved in the field
%% specified in the first row of that column. The first row (field names) 
%% of the excel file contains only strings. The second row onwards can have
%% either strings or numbers. However, each column will contain only one
%% type of data (i.e. either numbers or strings). The attached figure
%% (ques1.jpg) helps explain what you have to do.
%% If the file is a .txt file, you have to do the exact same thing, except
%% that the data is in this text file and it is tab delimited.
%% Notes:
%% 1) The excel file contains only 1 sheet.
%% 2) You do not know how many rows and columns contain values
%% 3) The name and number of fields (first row) can be different for
%%    different input files.

The question I have is this:

I have a text file as shown below: (tab delimited)(each name starts a new row, but i'm not familiar with wikipedia formatting, so it should be a 4 column, 3 row matrix.

Sally     Type1  12.34  45  Yes
Joe       Type2  23.54  60  No
Bill      Type1  34.90  12  No

how do i use DLMREAD to input that data? anything i tries error outs if there's a string in the .txt file, and not just numbers. Thanks so much in advance!

I haven't read your question fully but I'll give you an example from my old lecture notes and maybe that will help. When is this thing due? If it's not due today then I will give you further help (since I'm busy using MATLAB ironically), or maybe someone else will.
Here it is:
%Code to break a line of text into tokens and store in a cell array
line= 'MATLAB is an excellent prgram yada yada';
ii=1
while any(line)
[token{ii}, line] = strtok(line);
ii=ii+1;
end
Please ask again if you need more help.--Commander Keane 01:52, 13 October 2005 (UTC)
Added <pre> tags to make the code readable --WhiteDragon 17:58, 13 October 2005 (UTC)

The effect of agriculture on soil[edit]

I know that plants use nutrients from the soil in order to grow. What I'm wondering is if the amount of nutrients is limited. Suppose a farmer— an ancient or medieval one, not a modern one— uses a given plot of land for growing crops. Do the nutrients in the soil get "used up" by the crops, to the point where it eventually won't be able to support new plants? If so, how long can a given chunk of land be used for growing crops? If not, then can a farmer use the same soil over and over again?

I realize that these are rather broad questions that could have complicated answers, but I don't need all of the details. I'm only using the information to create the history of a fantasy world in a novel I'm writing, so vague generalities are fine. —Saric (Talk) 01:14, 13 October 2005 (UTC)

There are really a lot of variables here, depleting the nutrients in the soil would vary with the type of soil, crop management practices - like crop rotation which can restore some nutrients to the soil, the type of crop grown for example legumes can grow in nitrogen poor soil which other crops could not grown in since they form symbioses which give the nitrogen, and weather conditions are just a few things to consdier. The level of technology would also affect how much people understand this, for example in some parts of Papua New Guniea they cut down a small section of rainforest, grow their crop there for a few years, then move on to a new spot since the land is not as productive after a while, whereas in places like the US a farmer would just apply fertilizers to maintain a level of productivity.--nixie 01:24, 13 October 2005 (UTC)

Another way that nutrients are replenished is through periodic flooding. Seasonal flooding deposits silt loaded with organic matter on floodplains adjacent to the river. (This process made the Nile Delta highly fertile farmland for thousands of years. Unfortunately, construction of the Aswan High Dam has ended the annual floods.) TenOfAllTrades(talk) 04:26, 13 October 2005 (UTC)

I agree and add that ancient farmers had a way to replenish the soil, too, with manure. It can add back many of the lost nutrients. StuRat 04:38, 13 October 2005 (UTC)

Other things affecting the ability of soil to sustain agriculture for long periods is exposure of the area to recent (in geologic terms) glaciation or volcanism. Qaz (talk) 05:33, 13 October 2005 (UTC)

This is a partial repetition of what has already been said, but it is mostly a matter of putting back in what you take out. Manure does that (ground > plant > cow-or-whatever > dung > ground). Which is also the way it works in nature (leaves falling on the ground get turned into fungus dung or something). But if you constantly grow the same crop you take out the specific nutrients that that plant needs, and manure isn't usually that specific (or is it ever?). It isn't usually natural to have a long-lasting monoculture (except on poor soils, ironically).

Tropical rainforests are different. Over time the plants (trees) have absorbed all the nutrients in the soil. Anything that falls on the ground is absorbed again before it can sink into the ground. Which is why rainforest trees don't have roots that grow deep (there's nothing there) but spread out with buttresses. So if you take the trees out you're left with almost dead soil. I suppose it might work if you left all the trees to rot and then dig the remains into the ground (and maybe let that stand for a while). But that would take years and people aren't usually that patient. DirkvdM 08:46, 13 October 2005 (UTC)

Yes, it occurred to me several years ago that beneath the feet of the rain forest lies a desert. If the rain ever stops the desert will return.

Gravity and water?[edit]

Hypothetically, if I were to fall off a 200 hundred story building strait down into a deep body of water, would I land ok? I mean water is all soft an flowy, but would it provide enough support to stop me before I hit the bottom? Is this more or less safe then jumping onto a trampoline?--Talk to the yam 02:35, 13 October 2005 (UTC)

No, you wouldn't fall ok because your body's kinetic energy wouldn't be dissipated slowly. In fact, you'd hit the water as if you were hitting concrete, because the surface tension wouldn't let your body sunk immediately and the impact would be disastrous because of the extreme deacceleration you'd experience (causing a g force peak). All this energy released on a very small period would rip your limbs off your body and pratically destroy all your inner organs! ☢ Kieff | Talk 03:13, 13 October 2005 (UTC)

You's hit the water very hard because of the surface tension of the water.--Shanedidona 03:15, 13 October 2005 (UTC)

A minor physics nitpick—you're not hitting the water hard because of its surface tension; you're hitting it hard because of the water's inertia and viscosity. When you come in contact with the liquid surface, your body rapidly displaces water down and sideways to make room for itself. Since your density is roughly equal to that of water, every kilogram of your body you immerse means a kilogram of water that has to get out of your way. If you fall from a significant height, when you hit you need to move a lot of water very quickly. That transfer of kinetic energy from your body to the surrounding water is fast and painful. TenOfAllTrades(talk) 04:17, 13 October 2005 (UTC)

It is fast and painful, but not as fast and painful as hitting granite or some other hard stone. I wonder if there are any statistics of parachutists with chutes failing to open over water?
I agree and would add that the density of the water is also critical. If you've ever done a belly flop into a pool, you know just how much water can hurt. Now multiply that by 100 and you have an idea how hitting water at those speeds would feel. StuRat 04:31, 13 October 2005 (UTC)
See also Diving#The_effect_of_height_on_the_dive. This claims 66 metres to be almost certainly fatal. What's that – a 22 storey building? The article doesn't dwell on the maximum speed, but terminal velocity would be reached long before 200 storeys. Unfortunately, terminal velocity may be even higher if you adopt a streamlined diving position in the hope of survival. Apparently cliff divers regularly compete at 25 metres. I suspect that with some additional accessories, like a very pointy hat and shoulder protection, higher dives could be survivable. Notinasnaid 08:09, 13 October 2005 (UTC)


Well, it of course depends on how you hit the water. If you hit it belly down a 10 m drop would already be lethal I guess. But I once heard of a guy who jumped off a burning oil platform and survived (something one isn't supposed to do when jumping of an oil pllatform :) - they can be hundreds of meters high). I don't know how he did it, but I suppose that if you fall vertically you might just break your ankles. The first meter or so won't cause too much of a water displacement, but your feet will greatly reduce your speed - maybe the guy had big feet :) . DirkvdM 08:44, 13 October 2005 (UTC)
Mythbusters ran a segment on this concept, and the general consensus was that such falls were, statistically, uniformly fatal. Of course, there's still the one-in-a-million survival without reason (just like a handful of people have apparently survived unopened parachutes). — Lomn | Talk / RfC 12:41, 13 October 2005 (UTC)
I hear that the way to survive an unopened parachute is to maximize surface area while falling to fall as slow as possible and then arrange yourself before you hit so that a few of your biggest bones break instead of a hundred smaller bones. (I seem to recall the position is curled up on your side with your head protected in your arms, which is intended to let amongst others your arms, shoulder blades and pelvis break while preserving your skull and back.) If true this would probably be the only possible way to survive a fall into water, too, but I certainly wouldn't try it. — Laura Scudder | Talk 17:38, 13 October 2005 (UTC)
This is unsourced and most likely unconfirmed, but there was a guy who fell of a bridge he was working on, and threw his hammer into the water just before he hit, thus "breaking his fall" and i think he got away with just minor injuries. I think it was true, but, you know. :) --Ballchef 13:06, 13 October 2005 (UTC)
This is the specific case from Mythbusters and it was conclusively debunked. As noted by TenOfAllTrades, surface tension is not responsible, and a hammer does not affect the viscosity of water. — Lomn | Talk / RfC 13:16, 13 October 2005 (UTC)
Ah, so that's where i saw it. thanks --Ballchef 13:30, 13 October 2005 (UTC)
The hammer does not affect the viscosity of the water, but if the hammer fell in first it might create a 'hole' in the water if the timeing were just right and then the man would fall into water th