# Wikipedia:Reference desk archive/Science/October 2005

## Greatest Common Factor / Least Common Multiple Problem

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

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?

• 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?

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

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

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?

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

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?

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

## Bermuda Triangle

What is Bermuda Triangle?

## branded product marketing

Did you have a question? — Nowhither 00:24, 24 September 2005 (UTC)

## Quarks

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

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?

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?

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

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

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

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

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

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

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

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)

## -1=1

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.

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

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

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

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?

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

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

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 ????

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 (talk, contribs) 19:08, 24 September 2005 (UTC)

## Drawing electrical circuits

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

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

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?

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

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

(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  | Talk 00:48, 25 September 2005 (UTC)

## Alternator wire

what is the maximun voltage drop allowed on an alternator wire on a vehicle

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

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

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?

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

## How much does 7 liters of gasoline weigh?

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) 01:15, 29 September 2005 (UTC)

## Stanis?aw Ulam

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...

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

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

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

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

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

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

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

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

And for three dimensions you go:

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

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

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

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! ${\displaystyle {\begin{vmatrix}+&-&+&-&...\\-&+&-&+&...\\+&-&+&-&...\\-&+&-&+&...\\...&...&...&...&...\end{vmatrix}}}$ --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

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

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.

## Normalization of scale

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

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

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

## what is dsl?

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

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

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

## Periodic Table

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

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

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

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

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

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

## neurons

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

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

## SNP

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?

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

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

## 3D Shape Problems

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

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?

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

## Dental polymers

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

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 ${\displaystyle x\in (-1,1)}$. Now, then, first it'll help to split up the problem as follows:
${\displaystyle ln({\frac {1+x}{1-x}})=ln(1+x)-ln(1-x)}$
Now we'll work on the second term, and later get the first from it. First, note that
${\displaystyle {\frac {1}{1-x}}=1+x+x^{2}+x^{3}+...}$
(To see this, just multiply both sides by 1-x.) Now integrating both sides from 0 to x gives:
${\displaystyle -ln(1-x)=x+{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}+{\frac {x^{4}}{4}}+...}$
From this, replacing x by -x, we get
${\displaystyle ln(1+x)=x-{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}-{\frac {x^{4}}{4}}+...}$
Which going back to the first equation gives
${\displaystyle ln({\frac {1+x}{1-x}})=(x-{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}-{\frac {x^{4}}{4}}+...)+(x+{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}+{\frac {x^{4}}{4}}+...)=2(x+{\frac {x^{3}}{3}}+{\frac {x^{5}}{5}}+...)}$
Hope that helps! -- SCZenz 20:40, 2 October 2005 (UTC)

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

How would one expand ${\displaystyle g(x)=sin(x)\,}$ in powers of ${\displaystyle x-pi\,}$? 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 ${\displaystyle y=x-\pi ;\,}$, then using ${\displaystyle sin(x)=sin(y+\pi )=sin(y)cos(\pi )+cos(y)sin(\pi )=-sin(y)\,}$. Then do the usual expansion about ${\displaystyle y=0\,}$, 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 ${\displaystyle ''x''=''a''\,}$:
${\displaystyle f(x)=f(a)+f^{\prime }(a)(x-a)+{\frac {1}{2}}f^{\prime \prime }(a)(x-a)^{2}+\ldots {\frac {1}{n!}}f^{n}(a)(x-a)^{n}+\ldots }$
Notice that this expansion is what you want for a = π and f(x) = sinx. Then
${\displaystyle f(\pi )=\sin \pi =0\,}$
${\displaystyle f^{\prime }(\pi )=\cos \pi =-1\,}$
${\displaystyle f^{\prime \prime }(\pi )=-\sin \pi =0\,}$
${\displaystyle f^{3}(\pi )=-\cos \pi =1\,}$
${\displaystyle f^{4}(\pi )=\sin \pi =0\,}$
Now we can see a pattern: these values of the derivative will simply repeat, and the Taylor series will be:
${\displaystyle \sin x=-(x-\pi )+{\frac {1}{3!}}(x-\pi )^{3}-{\frac {1}{5!}}(x-\pi )^{5}+{\frac {1}{7!}}(x-\pi )^{7}\ldots }$
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?

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?

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) 14:35, 4 October 2005 (UTC)
Diet soda has more caffiene then regular. --Phroziac(talk) 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?

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?

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

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:
${\displaystyle a^{2}+b^{2}=c^{2}}$
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:
${\displaystyle a^{2}+a^{2}=12^{2}}$
${\displaystyle 2(a^{2})=144}$
${\displaystyle a^{2}={\frac {144}{2}}=72}$
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

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)

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

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

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?

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

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.

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

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

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

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>

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?

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

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?

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

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

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

## what causes food decay

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

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'

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

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?

I understand because they conduct heat away more efficiently than other materials, but is there a more scientific explanation for this? - Cobra Ky (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 (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 (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

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

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

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

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

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

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

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?

yes


## Health effects of tea vs. coffee?

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

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)

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

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.

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.

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

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?

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

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

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

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

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

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

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

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

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

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

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)

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

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

## Random vector member?

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 ${\displaystyle l}$ in the vector (my C++ is very rusty, but isn't that the length method of the vector class)?
2. Generate a random number ${\displaystyle i,0\leq i 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

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

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

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

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

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)

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

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

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

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

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,

• 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

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?

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.

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

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

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?

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 (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

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

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

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

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?

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

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

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?

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

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)

## Sun & planet gear & epicyclic gearing

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.

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

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

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

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

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)

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)

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

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)

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

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)

## Ears

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

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?

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?

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 (talk, contribs) 17:18, 7 October 2005 (UTC)

## medical term

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....

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