Wikipedia:Reference desk/Science

Reference Desk

Science Mathematics Computing/IT Humanities Language Entertainment Miscellaneous Archives
How to ask a question Search first. It's quicker, because you can find the answer in our online encyclopedia instead of waiting for a volunteer to respond. Search Wikipedia using the searchbox. A web search could help too. Common questions about Wikipedia itself, such as how to cite Wikipedia and who owns Wikipedia, are answered in Wikipedia:FAQ.
Sign your question. Type ~~~~ at its end. Be specific. Explain your question in detail if necessary, addressing exactly what you'd like answered. For information that changes from country to country (or from state to state), such as legal, fiscal or institutional matters, please specify the jurisdiction you're interested in. Include both a title and a question. The title (top box) should specify the topic of your question. The complete details should be in the bottom box. Do your own homework. If you need help with a specific part or concept of your homework, feel free to ask, but please don't post entire homework questions and expect us to give you the answers. Be patient. Questions are answered by other users, and a user who can answer may not be reading the page immediately. A complete answer to your question may be developed over a period of up to seven days.	Do not include your e-mail address. Questions aren't normally answered by e-mail. Be aware that the content on Wikipedia is extensively copied to many websites; making your e-mail address public here may make it very public throughout the Internet. Edit your question for more discussion. Click the [edit] link on right side of its header line. Please do not start multiple sections about the same topic. Archived questions If you cannot find your question on the reference desks, please see the Archives. Unanswered questions If you find that your question has been archived before being answered, you may copy your question from the Archives into a new section on the reference desk. Do not request medical or legal advice. Ask a doctor or lawyer instead.
After reading the above, you may ask a new question by clicking here. Your question will be added at the bottom of the page.
How to answer a question Be thorough. Please provide as much of the answer as you are able to. Be concise, not terse. Please write in a clear and easily understood manner. Keep your answer within the scope of the question as stated.	Link to articles which may have further information relevant to the question. Be polite to users, especially ones new to Wikipedia. A little fun is fine, but don't be rude. The reference desk is not a soapbox. Please avoid debating about politics, religion, or other sensitive issues.

standards in wiring

What is the purpose of standards in wiring?

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

Safety is also an issue.

.9999… = 1?

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

1-0.99… = 0.00000000… There are several other nice proofs, but I'm not sure if we have an article on the matter. I'm sure someone else can help you with that though. --fvw* 03:24, 28 September 2005 (UTC)

One way to see this is to observe 1/3 = .333..., so .999... (which is clearly 3 times .333...) must be the same as 3 times 1/3. Another way is to convert it to a fraction. Let X=.999..., then 10X=9.999..., and 10X-1X = (9.999... - .999...) = 9, so 9X = 9, i.e. X=1. If none of these do it for you, you might try the explanation at http://mathforum.org/library/drmath/view/55746.html. -- Rick Block (talk) 03:34, 28 September 2005 (UTC)

Actually, we do have an article on this: Proof that 0.999... equals 1 --Pidgeot (t) (c) (e) 12:14, 28 September 2005 (UTC)

From a no-equations-involved standpoint, we know that there are infinitely many numbers between any two distinct numbers on a number line. Now, what form would a number take to be greater than 0.9999... and less than 1.0? No such number exists, therefore 0.9999... and 1.0 are not distinct (that is, they are equal). — Lomn | Talk / RfC 13:27, 28 September 2005 (UTC)

Use a calculator to square the square root of 2 and deduct 1. This will confirm that 1 is 0.9999.... ;-) Shantavira 17:22, 28 September 2005 (UTC)

For the hapless reader that doesn't reallize the above is a joke, see round-off error and the field of numerical analysis that studies that kind of thing. - Taxman ^Talk 18:40, 28 September 2005 (UTC)

It basically follows from the completeness property of real numbers. Read the properties section of that article if you really want to dig into the gory stuff. Our article doesn't use the infimum and supremum language I learned in advanced calculus, but that was a while ago and I forgot the completeness formulation in those terms. Those articles cover the basics. - Taxman ^Talk 18:40, 28 September 2005 (UTC)

Aren't natural numbers and rational numbers mixed up here? I suppose one might argue that 0.99999.... equals 1.00000.... . But 1 (without a decimal dot) is a natural number and 0.9999.... might come infinitesimally close to that, but never reaches it. So for all practical purposes they're equal, but mathematically they aren't. Right? DirkvdM 21:04, 28 September 2005 (UTC)

Again, see the article, but to summarize, any two unequal real numbers (reals) have an infinite quanitity of reals between them. What reals are between .99999... and 1? Superm401 | Talk 21:45, 28 September 2005 (UTC)

0.999... can only be defined in terms of the limit of a series. The series is in the rationals, and it converges to a natural number, 1. That's it. One important fact you need to know is that there are no infintesimals in the theory of real numbers. There are some funky theories you get in logic courses that have infintesemals, and you can do stuff with them instead of limits; I don't know how you would define 0.9999.... in that scheme, but it's irrelevant anyway. -- SCZenz 21:57, 28 September 2005 (UTC)

It is also important to note that 0.999... is a number, not a process. There is no "getting closer", 0.999... is a number, period. In calculus you will learn that decimal numbers are compact representations of infinite series, and that the series represented by 0.999... converges to its limit, 1. Here again, "converges" is a static property, not a process. Vonspringer 04:21, 4 October 2005 (UTC)

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

severe hypoglycemia

• Our Hypoglycemia article may be able to help you out. Capitalistroadster 05:57, 28 September 2005 (UTC)

How can I view a unix manpage in Microsoft Windows?

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

You can download Cygwin and install it. When done, save the file to the man directory and a man ccdoc should be enough, or download and compile the ccdoc source (again, in Cygwin).

Afterwards, you can add the bin directory of your Cygwin installation to your path to be able to read the man page without having to enter bash every time. --Pidgeot (t) (c) (e) 09:37, 28 September 2005 (UTC)

Also try looking for programs to convert manpages to something you can read [1] Ojw 21:25, 30 September 2005 (UTC)

BEARD GROWTH

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

• because that doesn't have much to do with evolution, you should get better teachers.. also human population growth is exponential, that means at some point, we break the evolutionary mold, in shorter words, we're an evolutionary dead end, much like the neanderthal, and you know what happened to that guy--205.188.117.71 03:54, 29 September 2005 (UTC)

It isn't enough that something not be useful for it to evolve away, it needs to have a detrimental effect. (See vestigial organ) A tail has muscles, bones, etc that need maintainance (and maybe get in the way for certain types of walking). I don't think a beard takes much of the body's resources to make. And I imagine that shaving has been in practice for a very tiny fraction of the time that not-using-one's-tail has. Frencheigh 10:38, 28 September 2005 (UTC)

"stopped using their tail which eventually led to most of the tail missing". No, it didn't. That is similar to the evolutionary theory of Lamarck, which has been disproven. Lamarck believed(among other things) that use of organs would cause them to grow while disuse would make them shrink. Again, this is not correct. Evolution occurs through natural selection(or "survival of the fittest"). In summary, all individuals pass traits(phenomes) to their children through genes. Those individuals that are most successfully adapted will be more likely to reproduce, as well as likely to reproduce more. Therefore, more descendants will have their phenomes and genes than those of the less successful individuals. Eventually, only the descendants with the superior adaptations survive, forming new species. Genes are modified through mutation. Superm401 | Talk 21:59, 28 September 2005 (UTC)

I aggree that, in proper terms, great apes stopped having (noticeable) tails, which then prevented us from using them. One thing to note is that, for an individual creature, disuse of certain organs (especially bones and muscles, as mentioned above) causes them to atrophy. This change doesn't propagate to new generations, but it is an easy-to-observe exampe of organs shrinking with disuse.--Joel 19:12, 3 October 2005 (UTC)

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

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

What is sirolimus

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

multiple sclerosis

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

hydrogen bonding

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

By any chance, was intermolecular forces supposed to read as Van Der Waals forces ? you may as well post the entire problem, I could use some practice with my differentials--205.188.117.71 03:51, 29 September 2005 (UTC)

According to Hydrogen bond, it's an intermolecular bond. So I assume that the intramolecular case you refer to would just be an "intermolecular" bond between two atoms that happen to be far apart in the basic covalent structure of the same molecule (contributing, e.g. to protein folding). That being the case, I would expect the two cases to be of equal strength if all else is equal. -- SCZenz 15:43, 28 September 2005 (UTC)

Please refer to the top of this page, and note that Wikipedia isn't here to answer your homework questions. TenOfAllTrades(talk) 16:16, 28 September 2005 (UTC)

On the bright side, if that was a homework question, what I said almost certainly wasn't the answer the instructor was looking for. ;) -- SCZenz 17:30, 28 September 2005 (UTC)

Cephlapods and regeneration

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

• "the squid's tentacle would not grow back "[2] Samw 21:56, 30 September 2005 (UTC)

Wikipedia Problems??

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

This sometimes happens when a section header is not formatted correctly. Fixed (I think). --hydnjo talk 01:47, 29 September 2005 (UTC)

I think the poster is thinking as I did at first, and assuming a section's edit button is the one that follows the text. In fact a section's edit button is the one on the same line as the section's title, above the horizontal rule that preceeds the text; not the one that sitting there, temptingly, right where your addition will go. I found this counter-intuitive. And for long sections the edit button has scrolled off-screen. Sharkford 14:38, 30 September 2005 (UTC)

I believe the same problem occurs when headers are commented out -- don't know whether this is fixed or not. Dysprosia 22:23, 3 October 2005 (UTC)

Lord Ned

Lordned 17:39, 28 September 2005 (UTC)

The section edit link in the default skin is to the right of and just slightly above the section title. This can make it look as if the link applies to the previous section, when it does not. This is, I'm afraid, just soemthing you need to get used to. DES ^(talk) 17:53, 28 September 2005 (UTC)

On related issues, you delete a duplicate section by editing the whole page and removing it, or by editing one of the duplicates and deleting the entire contents, including the section header. I did this for your duplicate post. Also when you start a line with a space character it produces a fixed-font, un-wrapped, boxed text. This is usually not what is desired. Do indents by starting the line with one or more colons. It is not standard on wikipedia to indent the first line of a paragraph. DES ^(talk) 17:53, 28 September 2005 (UTC)

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

That happens. Alos on discussion pages (like this one) it is a good idea to sign your comments with four tildas (like this ~~~~). DES ^(talk) 18:01, 28 September 2005 (UTC)

One more note; sometimes if there are multiple images stacked up next to an article, it will cause flaky behaviour of the [edit] boxes. None will appear next to one or more sections, and they will all pile up ([edit] [edit] [edit]) next to a later section in the article. TenOfAllTrades(talk) 18:39, 28 September 2005 (UTC)

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

63.199.33.66 16:38, 29 September 2005 (UTC)

puna multa

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

Hmmm. A number of links come up in Finnish when I Google that phrase, but my Finnish is, um, limited :) You might try asking one of the people listed at the Finnish Wikipedia Embassy if they can help you. --Robert Merkel 04:26, 29 September 2005 (UTC)

Bad hurricane cycles

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

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

hydrogen peroxide

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

quantitative methods and physical planning

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

Which quantitative methods? Chuck 20:35, 28 September 2005 (UTC)

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

Lagrange Minimization procedure

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

Actually, someone using the "add a new question" link at the top never uses wikiformatting to create the header. However, the above is correct -- this is not a search engine. However, this link over in Miscellaneous may help out. — Lomn | Talk / RfC 02:16, 29 September 2005 (UTC)

Epidemics indiana 1850 - 1860

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

indiana

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

PEANUT SKINS

ARE THEY GOOD FOR YOU TO EAT? JANET F.

Assuming that you don't mean the "shells" (the hard outer part that we usually throw away) but rather the thin, maroon colored "skin", I'd presume that they aren't bad for you to eat or they wouldn't be so readily available that way, but I suppose that same answer would apply to the hard outer shell as well! Also, the "meat" within called the peanut are OK for some folks and deadly for others. So, I have no idea if they "ARE THEY GOOD FOR YOU TO EAT? JANET F.", that's between you and your doctor. I can only tell you that they are not bad for me to eat. --hydnjo talk 00:25, 29 September 2005 (UTC)

If I had to guess, I'd say that they're not harmful. (I'm making the same assumption as Hydnjo does about what constitutes the 'skin'.) I suspect that they're loaded with insoluble fibre, which is good for your digestion. On the other hand, I find them a bit bitter and kind of dry, and they can cause an unpleasant tickle in the back of my throat when I eat them.

Ah; Google is your friend. An interesting link here. Apparently peanut skins are used as animal feed–suggesting that they're not harmful. It seems that they contain a number of useful fatty acids, too. TenOfAllTrades(talk) 01:44, 29 September 2005 (UTC)

what is a cell?

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

wonderland

who is the blue ferry?

Although this is when rather than who, I hope this is of some help. --hydnjo talk 00:31, 29 September 2005 (UTC)

Perhaps you mean the Blue Fairy, from the novel Pinocchio, who also features in the movie A.I.: Artificial Intelligence.-gadfium 03:45, 29 September 2005 (UTC)

Was there a furry in the "blue" (i.e., pornographic) version of Alice in Wonderland? I never saw it, but I would assume there was. If so, the credits would tell you who played what role.--Joel 19:26, 3 October 2005 (UTC)

What day is the North Pole tilted furthest from the Sun?

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

• I don't think so. See solstice. The first day of winter. --jpgordon∇∆∇∆ 02:52, 29 September 2005 (UTC)

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

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

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

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

Feces and foot

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

• Pekinensense,

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

Have you been vaccinated against Hepatitis B? If not, this is something to bring up on that doctor visit. - Nunh-huh 06:37, 29 September 2005 (UTC)

And, if you haven't already, clean the wound and disinfect it with something like iodine (the most common brand name solution is called "Betadine" as per normal first aid procedures. --Robert Merkel 04:21, 29 September 2005 (UTC)

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

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

Elemental lithium

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

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

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

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

According to our article on lithium salts, the chemical formula of lithium carbonate is Li₂CO₃. That there's one carbon and three oxygen atoms for every 2 lithium atoms in lithium carbonate.

From our entries on lithium, carbon, and oxygen the atomic mass of each is 6.974, 12.0107, and 15.9994. From this, we can calculate the fraction of the compound that is made up of lithium is:

${\frac {2\times 6.974}{2\times 6.974+12.0107+2\times 15.9994}}\approx 24\%$.

Therefore, 300mg of lithium carbonate would contains about 72 mg of elemental lithium.

Please note that Wikipedia does not give medical advice, and that incorrect dosage calculations are a regular cause of avoidable deaths in hospitals. So, whatever you do, please don't start dosing yourself purely on the basis of some quick calculations of somebody who hasn't done chemistry since high school.--Robert Merkel 04:15, 29 September 2005 (UTC)

To illustrate the problem, that equation should be

${\frac {2\times 6.974}{2\times 6.974+12.0107+3\times 15.9994}}\approx 18.86\%$

or 56.5 mg lithium for 300 mg lithium carbonate. Be aware as well that the bioavailability of metal ions is different for different salts. Physchim62 09:10, 29 September 2005 (UTC)

Whoops! I wasn't trying to illustrate the point, but hopefully people will take notice of the warning now that I've demonstrated how easy it is to screw up! --Robert Merkel 12:27, 29 September 2005 (UTC)

Our article on lithium orotate is not referenced, so it is subject to even more caution than usual. It may or may not give you some ideas to compare the two treatments. You may well wish to ask yourself why the FDA does not approuve this treatment (or, even better, ask them and tell us why!). Physchim62 14:15, 4 October 2005 (UTC)

are the stars we see in the nights sky actually suns

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

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

suns and stars

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

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

Nuclear blast in eye of hurricane..

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

bukhrin

I don't think anybody's ever asked before, though you probably could do a simulation if you had access to weather-forecasting computer code. One side effect that's easy to predict is the distribution of dangerous nuclear fallout over a wide area, which could render places in its path uninhabitable for years, perhaps even decades, afterward. --Robert Merkel 07:47, 29 September 2005 (UTC)

though you probably could do a simulation if you had access to weather-forecasting computer code. Don't forget to budget for several days on the nearest supercomputer. :)--inks 12:18, 29 September 2005 (UTC)

It would probably not do much to disrupt the hurricane. The energy in a hurricane (see [3] for example) is several orders of magnitude greater than the yield of existing nuclear bombs. Fredrik | talk 11:01, 29 September 2005 (UTC)

Interesting experiment though. A FAE (Fuel-Air Explosion) approaches the strength of a Nuclear Weapon by purely chemical means, so if this were done there would be no nuclear fallout from it.

They only approach the yield of the tiniest nuclear weapons, though. --Fastfission 16:03, 29 September 2005 (UTC)

I doubt it would do anything at all. Even a Tsar Bomba sized blast pales in the overall, cumulative energy present in a hurricane. If you look at our entry on kiloton you can see how much more raw energy natural phenomena has in general (the reason that the bombs seem so big, of course, is that they release all of their energy into a relatively small space and over a very small amount of time). --Fastfission 15:36, 29 September 2005 (UTC)

The NOAA answers this question in their Hurricane FAQ. — File:Ontario trillium sig.pngmendel ☎ 17:08, 29 September 2005 (UTC)

1. Delivering a nuke to the eye of a storm would require some fancy footwork, missile technology not something that your average troublemaker might have in the near term.
2. Do Google search ... there are places where you key in geographic location and how big some event to see damage from WMD, giant meteor strike, earthquake, other disasters.
3. Watching on TV news huge traffic jam of people evacuating at last minute, it occurs to me we are kind of asking for trouble, since this goes on TV news world wide to all kinds of audiences.
   1. major hurricane is coming, approx where, announced days in advance
   2. local leaders take forever to discuss the implications of what is obvious to everyone, who knows anything, such as
      1. here comes category 4-5 and the flood control is only designed to handle category 3, and the city is under sea level, so after landfall it will be under water
   3. during that predictable time frame when the local leaders cannot decide what to do, terrorists blow up major escape highways with conventional explosives, stockpiled in geographic areas where the Atlantic hurricane season is known to be active.

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

To paraphrase NOAA:

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

Ojw 18:50, 1 October 2005 (UTC)

migraines

• Our Migraine article is quite detailed and would be a good place to start. Capitalistroadster 08:07, 29 September 2005 (UTC)

how to improve migraines

• Our Migraine article contains extensive information on migraine treatment. Your doctor will probably be able to advise of treatments if you suffer from them. Capitalistroadster 08:09, 29 September 2005 (UTC)
• Improve them? Few sufferers want them to get worse. Cure them perhaps was what you wanted to ask about. AlMac|^(talk) 01:15, 30 September 2005 (UTC)

I hear that Oliver Sacks finds his migraines to be quite entertaining, like a light show. I'm not sure modern medical science has found a way to turn ordinary sufferers into Hildegard of Bingen, but perhaps this person is looking for a way to improve the head trip.--Joel 19:39, 3 October 2005 (UTC)

how wind blows?

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

Have you tried reading our article on Wind? There should be some information there. From what I can ascertain, there are a variety of types of wind that have different causes.. but you should definitely read that article. splintax ^(talk) 08:42, 29 September 2005 (UTC)

All wind is fundamentally caused by pressure differentials. Many factors affect that pressure, and the differing linear speeds(though constant angular speed) of rotation at different latitudes affect apparent direction. See also "Why does wind gust?" above. Superm401 | Talk 13:59, 29 September 2005 (UTC)

construction technology of rotating buildings

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

Several cities have restaurants on top of high buildings, in which only the top rotates. You sit at window seat, and in an hour it has rotated so you get to see the whole city. I have never heard of an entire building rotating. AlMac|^(talk) 19:15, 29 September 2005 (UTC)

Glasgow Science Centre does. Or was supposed to, anyway. Notinasnaid 22:22, 29 September 2005 (UTC)

The largest and most numerous rotating buildings would probably be radio telescopes. I think they use circular tracks, along which a motor on the outside of the building travels. Ojw 19:47, 1 October 2005 (UTC)

mobile phone

Hi,

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

Bharathi.

• Some people believe the static electricity create when a mobile phone is used could cause an explosion which would be detrimental near petrol. However, the Mythbusters tried to cause an explosion using mobile phones and couldn't succeed unless they purposely created loads of static electricity (far more than a phone could generate). Still, there have been accounts of faulty and exploding batteries in phones which could still cause problems near petrol. Hope than answers your question. - Mgm|^(talk) 11:01, 29 September 2005 (UTC)

I'm not satisfied with their test, actually: they didn't set the phone to vibrate. In most direct current electric motors, the commutator throws up sparks several times a second as the motor runs. But in fact, I agree that this is more a question for the "culture" section of the reference desk...one reason I'm unhappy with this recent segmentation of the project.--Joel 17:49, 29 September 2005 (UTC)

• They did do a follow-up experiment to address multiple issues viewers brought up, but I can't remember the result. Sorry. - Mgm|^(talk) 19:12, 29 September 2005 (UTC)
• Surprisingly I found an article on MythBusters Episodes the mobile phone myth is listed in season 1 (episode 2) and season 2 (episode 14). - Mgm|^(talk) 19:23, 29 September 2005 (UTC)

It failed both times. --R.Koot 10:10, 30 September 2005 (UTC)

IIRC, they didn't turn on the vibrator for the second test, either, despite all the sex toy jokes it could have sparked. Oh, well...my fault for keeping my criticism to myself the first time around. To be honest, though, I would expect the microphone holes etc. in a cell phone to be too small to allow a flame front to pass. --Joel 19:44, 3 October 2005 (UTC)

Botany

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

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

Energy Drink Question

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

--Thanks, J

Found this using google. Active ingredients: Taurine, Caffeine, Ginseng, Vitamin B3, Vitamin B5, Vitamin B6, Vitamin B12. My guess would be that this contains more caffeine than a coke, so you need to drink less of it for the same effect. --R.Koot 16:08, 29 September 2005 (UTC)

If your diet is extremely bad, you might feel a lack of energy due to mild pellagra or some other deficiency disease, in which case XS Citrus Blast would make you feel revived beyond the sugar and caffeine...but eating a balanced diet would make you feel even better.--Joel 17:12, 29 September 2005 (UTC)

Is evolution scientific?

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

I don't think it's real at all, just another leftist conspiracy, much like... gravity, and that whole "round earth" business, If the earth is really round, and it really spins around the sun, then why don't I fall off when I'm on the bottom? Answer that smart guy--172.208.123.70 14:29, 2 October 2005 (UTC)

Evidence of evolution might be a good place to start. -- SCZenz 15:26, 29 September 2005 (UTC)

What you are referring to is the notion of falsifiability. Whether or not evolution is falsifiable depends on who you ask (creationists would probably interpret it to say no, philosophers might sit on the fence, scientists would say yes) — as a philosophical concept, it is not as cut-and-dry a test as people opposing creationism/ID usually make it out to be (though I personally think that in this instance, their overall conclusion is probably correct).. A lot of depends on whether you are taking evolution "as a whole" the entity which needs to be falsified or whether or not you are taking specific claims, and a lot of it also depends on what version of falsifiability you use. One fairly intelligent page which argues that evolution is falsifiable is Talkorigins.org: Evolution and Philosophy. --Fastfission 15:27, 29 September 2005 (UTC)

That is correct. I do not of any experiment that would disprove evolution, but that does not mean someone won;t come up with one sometime. This is impossible with Intelligent Design as you could always counter with "it was designed that way", while with evolution the theory has to modified or discarded. See Lamarckism, evolution, evidence of evolution, Intelligent Design and scientific theory for some more information. --R.Koot 15:28, 29 September 2005 (UTC)

Another way in which ID is unscientific is that it does not deal with a repeated mechanism of the natural world that operates under self-consistent rules. It just has some being who does what he feels like. -- SCZenz 15:33, 29 September 2005 (UTC)

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

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

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

(adding during edit conflict with above three responses)

A scientific theory (versus just any ole theory) is one that makes testable predictions. As you intimate, a theory without testable predictions is impossible to disprove and rather useless to a scientist. So for instance, I could come up with a theory of everything that was simply a list of observed occurances: in other words a theory that simply described the way things are and said "this is how it is". That theory would not be a scientific theory, because it would make no new predicitions, not to mention being really unsatisfying as it wouldn't "explain" any observations with underlying principles.

A prof of mine once said, "every great theory swallows it's predecessor whole," meaning that for a new theory to gain ground it needs to explain all the behavior described by the old theory while making an entire set of new, experimentally testable predictions. A great example is quantum mechanics, which swallowed Newtonian mechanics whole and then made an entire set of new predictions which have been tested rather extensively. It's not complete, but it's more complete than Newtonian mechanics, so it was eventually accepted by the scientific community, which is now trying to find the next, more complete sucessor theory.

In contrast, Intelligent Design — like my first example — makes no testable predictions. It is therefore not a scientific theory and is completely ignored as a possible replacement for evolution by the majority of the scientific community.

Right now, evolution is backed by so many observations that all scientific debate in the field centers on the details, not the basic principle of evolution. I cannot therefore anticipate anyone developing a scientific theory that can explain all those observations without also having evolution at it's core. — Laura Scudder | Talk 15:43, 29 September 2005 (UTC)

(adding during edit conflict with above four responses)

Evolutionary biology is a living science which is full of falsifiable hypotheses. Every publication in systematics which overturns existing ideas about systematics disproves some idea about evolution. If existing phylogenies say that species A and species B are more closely related to one another than they are to species C, that is an evolutionary hypothesis. Now, suppose someone comes along and looks at the genetics of the two species and concludes that species A and C are closely related, and species B is more distantly related. Assuming that their data are sound, this person has disproven an evolutionary hypothesis. Another way of disproving evolution would have been the discovery of an invariant fossil record - that, no matter how far back you go, you find the same set of modern living species. If you could find modern species in hundred million year old strata, then you would have evidence to disprove the hypothesis that the species you found evolved.

It's a little like heliocentric theory - when it was proposed that the earth revolved around the sun, there was a competing hypothesis that the sun revolved around the earth. Heliocentricity was confirmed experimentally, so now someone could come along and say "this is an unfalsifiable theory". Difficult to falsify it now (although there are still geocentrists out there), because it has already been falsified. Similarly, the existence of a fossil record makes it look like evolution is unfalsifiable because there is overwhelming evidence that it has taken place. But it still remains falsifiable. Guettarda 15:46, 29 September 2005 (UTC)

Has geocentricity been fansified? As I understand it the theory works, but is just much more complicated than heliocentricity and it's customary to work sith the simplest solution. DirkvdM 19:43, 29 September 2005 (UTC)

Just a few notes: theories often don't swallow entire previous theories whole (they often decide previous aspects of theories are not longer worth paying attention to, a la Thomas Kuhn); and in this case we're not talking about falsifiability in the sense that any given result will necessarily either favor one whole theory or another (the heliocentric question is not a great example in this case, as there are no "phases of Venus" to compare it to in evolution); and lastly, one of the other reasons that scientists say ID is "not science" is because it invokes non-natural causes as explanations (i.e., it invokes the supernatural), and "science" deals only with the natural world (once you start a science of the "supernatural" world, there is no end of explanations which are equally plausible). The requirement of science to use methodological naturalism has been criticized by IDers (notably Johnson) who say that it necessarily promotes an atheistic view of the world (even though it was originally formulated by Christian scholars, mind you). None of these critics, though, have adequately (in my mind) provided an acceptable view of what a non-materialist methodology would be which doesn't immediately snowball into the possibility of introducing supernatural explanations into anything we don't understand (as a related problem, see god of the gaps). What "is" and what "is not" science is a difficult thing to determine, though, and after a few centuries of intense debate nobody has yet come up with a great way of determining such a thing (see demarcation problem). So it's a sticky issue in a philosophical sense. But most of this (on both sides) is more about politics than it is true philosophy. --Fastfission 16:15, 29 September 2005 (UTC)

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

There are lots of 'holes' in evolutionary theory, based partly upon inexplicable fossil evidence. But due to the fact that this evidence was created long before people were around to observe it, it is entirely possible the evidence has been corrupted in some way which is not detectable yet, or maybe ever. Take Piltdown Man as an example.

I think we have deviated from the original question significantly. The answer is yes, the theory of evolution is scientific, for that reason it remains a theory and probably will for some time as the complexity of proving it or disproving it will require a lot of modification of the theory.

Falsification is really about designing an experiment, making a prediction and checking if that holds true. So you might claim that you could create a new animal out of an existing animal. Such as a Russian experiment I once head of where over tens of years tame foxes were created by interbreeding the meekest specimens over and over again. But if something like this fails then that doesn't prove that you couldn't have make it work if you would have done it differently. The big problem here is that there are too many factors at play to design a good laboratory style experiment. Which makes it almost impossible to falsify the evolution theory (or rather too easy, which would invalidate any falsification). And it's even worse with fossil evidence. There's always the chance that you'll find an animal you can't explain. But if you only know the overall way evolution works and not all the intricacies then it's quite possible you can't think of a solution yet. But the point is that it is falsifiable (there is the possibility to find something that disproves it) and that makes it scientific.

Also, as said before, there is just too much evidence to suport it. It 'works', as proven by farmers who have bred loads of types of animals to suit their needs. And it just makes too much sense. It is hard to believe that it might not work. Offspring are on average like their parents and less adapted individuals are less likely to get offspring. Both true right? Take it from there and you get evolution. Whether this explains everything (such as the origin of life) is an altogether different matter. But that this basic form of evolution takes place is just too unavoidable not to be true. DirkvdM 19:43, 29 September 2005 (UTC)

The accumulation of previous evidence has nothing to do with whether a theory is falsified or not or replaced with another. The Newtonian theory accounted for every observation thrown its way with the exception of about three. But those three (perihelion of Mercury, Michelson-Morley experiment, and lastly the deflection of starlight around the sun) were enough to topple the whole thing for most physicists in favor of Einsteinian Relativity in the early 1910s. "Falsification" doesn't at all mean "replace with something totally difference which gives totally different answers." Young Earth Creationism will never be the answer to a falsified evolution (too many simple observations contradict its "predictions" over and over again), but that doesn't mean that the current understanding of evolution (as either fact or theory, in the Gouldian sense) is the last word in any event. --Fastfission 02:25, 30 September 2005 (UTC)

Indeed, falsification has nothing to do with whether there exists an alternative. Forgot to react to that. DirkvdM 17:32, 30 September 2005 (UTC)

AirBus 360 Questions

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

Did you mean JetBlue Airways Flight 292, which was an AirBus 320, or this another incident? In any case, commercial airplanes always touch down on their back wheels first--if one broke, the results would be rather catastrophic, I suspect. Even less-than-complete landing gear collapse can result in ground loop, according to the landing gear article. -- SCZenz 18:11, 29 September 2005 (UTC)

Yes i did mean " Did you mean JetBlue Airways Flight 292, which was an AirBus 320" So i was off by 40... Thanks. I wonder what would happend with a stratofortress. Or a boing 747, or an A-10.... Maybe will never know.

Become an aeronautical engineeer / mechanical engineer, and you might be able to get a job simulating those kinds of events. You'd probably need a CAD design of the plane to simulate how each bit of the landing gear fails and what else it affects, rather than just using a desktop flight simulator. Ojw 21:29, 3 October 2005 (UTC)

Chemical Structure of HCl

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

• Please tell me this is a joke.. no wait, hold on, while I'm here does anyone know the chemical formula of H2O?--172.208.123.70 14:26, 2 October 2005 (UTC)

The structure of HCl is very simple, it is just H-Cl, now hydrochloric acid is a bit different as HCl needs to be dissolved in water to act as an acid, but the term structural formula is not very appropriate to that.

Have you looked at the Wikipedia article: Hydrochloric acid? --hydnjo talk 20:48, 29 September 2005 (UTC)

Hydrochloric acid is an ionic solution, meaning it consists of H⁺ and Cl^- ions moving around freely in solution (presumably in water). As such, it has no molecular structure. If you mean hydrogen chloride gas, it's just the two atoms with a single covalent bond: H—Cl. --David Wahler (talk) 13:59, 30 September 2005 (UTC)

Mallard Duck

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

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

On the other hand, it might just be simpler to make some omelettes. ;-) Shimgray | talk | 21:34, 29 September 2005 (UTC)

Portable Application Environments

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

Thanks! James

This ZDNet article (which is the first result that came up in a Google search) explains that portable application environments are, essentially, an API that can be implemented to run on multiple operating systems and architectures. The Java programming language and its associated bits are the best known example, while the Microsoft .NET environment is another (along with a compatible open source project, the Mono development platform).

I assume that mobile computing systems refers to developing software for personal digital assistants and advanced mobile phones.

To become a professional software programmer in this field, like other types of programming, you should ideally go to college and do a degree in software engineering or computer science. To get experience in these specific portable application environments , you can download basic development tools for at least Java and Mono for free, and start learning them yourself. If you own a PDA or some mobiles, you can download development tools for them, too, and start experimenting with programming on them.--Robert Merkel 22:59, 29 September 2005 (UTC)

There's good theory, and there's real world.

I have not yet learned how to draw pretty pictures in Wiki like so many other people do.

Draw a triangle and at each apex place a word

Quality

Features

Speed to Market

These are the goals of anyone developing software for any market ... you want good stuff, interesting stuff, and get it out there before competitor companies get their stuff to market. In recent years quality has been sacrificed for the other two. Examples of quality is good security, not at risk of viruses malware, personal privacy not at risk of being violated, it doesn't break with stupid error messages.

Who is General Protection Default & why is the military interested in messing with my computer? <G>

Thus if you apply for a job at some company that wants to compete in this field, perhaps they not care about quality either, just cool features, rapidly developed. AlMac|^(talk) 03:26, 5 October 2005 (UTC)

where is ghana ?

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

Hybrids and percentile differences in DNA

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

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

What is the greatest percentile difference bewteen DNA in Humans?

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

I do not believe you can put your question in Wiki watch list. Here is how I watch my question(s) (only one so far):

1. Post the question hopefully correctly.
2. Get to table of contents and use that to link to the question.
3. The url is now just of the question.
4. Use my browser to capture this place to return to at a later date or time.
5. Do so.

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

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

who was galileo?

• Who was he?? A heathen I say!!! Spouting heracy about the sun not rotating around earth!!! I'll believe that when I see it.....dirty revolutionists, gravitaion is JUST A THEORY!!!!!!!--172.208.123.70 14:24, 2 October 2005 (UTC)

If you try typing "Galileo" into the search box on the left of this page, and had clicked "search", the very first link is to Galileo Galilei, the subject of your question. --Robert Merkel 22:42, 29 September 2005 (UTC)

Should there be a template for this sort of response? ;) -- SCZenz 22:53, 29 September 2005 (UTC)

I was going to create one which had the format of {{seearticle|Galileo Galilei}} but the amount of coding there is really not much less than "See our article on Galileo Galilei". Plus, we'd lose an opportunity for snarky comments! --Fastfission 23:44, 29 September 2005 (UTC)

But we could put a snarky comment in the template, and make the same one every time! Wouldn't that be fun? -- SCZenz 00:28, 30 September 2005 (UTC)

Create a special 'insult of the day' template that changes each time you view it -- that way you can spend your time coding MediaWiki instead of working at the reference desk. Ojw 21:16, 30 September 2005 (UTC)

For technical matters, you can crib off of the stub template from Uncyclopedia, but I'd prefer it if the humor itself came from in-house. They have a pretty slick setup, with a random result every page load. --Joel 20:08, 3 October 2005 (UTC)

Seizure Trigger?

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

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

Peer-to-peer wiki?

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

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

Technically possible? Sure. Easy? Not so much. The file sharing peer-to-peer programs (like kazaa or Napster) solve a problem closer to traditional web servers which is distributing the same content to lots of users. Rather than music or video files something like these programs could easily distribute static web pages. The question these sorts of clients throw out to the distributed network is basically "does anyone have a copy of <x>"? All the copies are presumably identical, so if any peer has a copy it's good enough. The essence of a wiki is that the web pages are writable as well as readable by anyone. This makes the question that would need to be thrown out to the distributed network "who has the most recent copy of <x>"? The naive peer-to-peer way to do this requires asking everyone in the network, which would not be feasible for anything except a trivally small network. The trick would be to allow the question to be answered without explicitly asking everyone in the network. If there aren't any centralized servers keeping track of all the content and who has what, I think this is at least a reasonably difficult problem. -- Rick Block (talk) 01:25, 30 September 2005 (UTC)

Aside from the problem of efficiency, there's also the question of security and vandalism prevention. There's nothing to stop anybody from setting up a peer which replaces every page in the wiki with spam and always distributes it as the most recent version. Perhaps you could set up some sort of dynamic, voting-based blacklist but it's not likely to be very easy. --David Wahler (talk) 13:51, 30 September 2005 (UTC)

How about this: everyone keeps a database of which page was edited when. Updates on this get syndicated to everyone. Everyone keeps a running copy of N articles, and subscribes to the diffs (which they request by watching the database and asking "anyone have that new update to WP:RD from 13:51, 30 September 2005? I think my copy is out-of-date." The system is set up so that at least M copies of this article are maintained, and during off-peak hours, the copies are compared and rectified, by majority rule. Especially if archive distribution (i.e., who keeps what article) is random, and if M is fairly large, this would seem to make vandalism more difficult than it currently is for Wikimedia. This seems plausible to me, but ianane (I am not a network engineer). Feel free to poke holes in this scheme if you see an opening. It would also be nice, because you could assign high M to popular/controversial artilces and save some bandwidth.--Joel 20:19, 3 October 2005 (UTC)

You should check out Freenet. Running a Wiki on it maybe possible... Haon 11:46, 5 October 2005 (UTC)

Global warming

What is global warming?

Please see Global warming. -- Rick Block (talk) 00:20, 30 September 2005 (UTC)

Tis just a wacky liberal conspiracy theory, like evolution and gravity....!

what is carbon dating

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

Is that the kind of snarky comment you wanted to put in a template? :) DirkvdM 18:05, 30 September 2005 (UTC)

Nah, that's the kind of snarky comment that proves we shouldn't have a template. It only works with carbon dating...! ;) -- SCZenz 20:18, 30 September 2005 (UTC)

In reference to this specific snarky comment, one would hope that whomever your sister is dating, that they contain substantial amounts of carbon :) --Robert Merkel 04:29, 3 October 2005 (UTC)

Which leads us to the unavoidable question if aliens would necessarily have to be carbon based. Which is a totally philosophical question which is not meant to suggest anything about SCZenz's sister :) . DirkvdM 18:45, 3 October 2005 (UTC)

History of Prednisone

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

• It was invented by Arthur Nobile. Not sure when the patent expired. --jpgordon∇∆∇∆ 01:38, 30 September 2005 (UTC)

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

what is the name for water tension

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

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

What is circular DNA?

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

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

In most cases, it's double-stranded, and in those cases, it's not different from a double helix; it still has a double-helical structure. The scale at which the double helix appears is much smaller than the scale of the circle formed by the DNA. Imagine if you took a telephone cord (the coiled kind used to connect the handset to the base on corded phones), unplugged both ends, then plugged both ends into one of those connectors usually used to connect two cords. The cord would now be circular on a large scale, but still coiled--helical--on a smaller scale. Similarly, double-stranded circular DNA is still a double helix on a small scale, and circular on a larger scale. Chuck 16:56, 30 September 2005 (UTC)

Also most bacteria have an enzyme complex that methylates their own DNA as a way of distignuishing it from invading viral DNA, it's essentially a way of adding specificity to certian bacterial lysases, so they don't cleave their own genetic material by accident.. I'm not sure but I imagine it would be hard to methylate helical DNA, but I don't know if the methylation would nesseserily change the conformation, of it it just takes advantage of the conformation change--172.208.123.70 14:16, 2 October 2005 (UTC)

Ignition point of wood in the absence of flame?

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

• I couldn't tell you for sure, but I'm confident it depends on exactly what kind of wood we're talking about. Redwood? Oak? Maple? Mesquite? - Cobra Ky (talk, contribs) 04:00, 30 September 2005 (UTC)

I believe at least book paper spontaneously ignites at Farenheit 451 (233 Celsius), hence, the name of the book. I would expect most woods would require a higher temperature. -- Rick Block (talk) 04:16, 30 September 2005 (UTC)

Respirable Liquid

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

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

Information system management

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

• See metadata, intranet, extranet and automation. - Mgm|^(talk) 07:47, 30 September 2005 (UTC)

Why a pair of bones?

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

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

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

staggered vs eclipsed conformations

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

cabi.

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

• Steric effects are mostly caused by the repulsion of the cloud of electrons surrounding atoms in close proximity of eachother. - Mgm|^(talk) 07:51, 30 September 2005 (UTC)

sex toy

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

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

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

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

Need a documentation tool for C

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

You can set Doxygen so that it creates HTML files that are visually identical to your source code, except with code colouring, and hyperlinks everywhere so that you can follow relationships -- this output seems to be much closer to what you describe than the default doxygen output. Haven't got a copy handy to tell you what the option's called, I'm afraid. Ojw 21:13, 30 September 2005 (UTC)

Something like Perl is Your Friend; if I understand your problem correctly, languages such as Perl are designed for particularly this problem. It's not really harder than "parsing the source code", though. Dysprosia 22:20, 3 October 2005 (UTC)

Unique Human bodypart?

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

I can't think of an obvious one. However, teeth are often unique to a given species - one of the points of contention over homo florensis involves the numbers of roots on a molar, or something - so you could possibly argue that our teeth are, in fine detail, unique to humans. Other than that, I suspect most things are shared with some form of ape. Shimgray | talk | 13:10, 30 September 2005 (UTC)

The obvious one is People have a much larger brain than any other creature.

Not at all, a wale brain weighs nearly 8kg (next to our puny 1.5kgs), see Whale for more information. --fvw* 13:29, 30 September 2005 (UTC)

Didn't know that, that is why I go to Wiki

Actually, contrary to popular belief, whale brains are pretty unimpressive for their body size, and don't really imply great intelligence (some dolphins, though, do have rather large brains for their body size).--Pharos 15:38, 30 September 2005 (UTC)

Of course the human brain doesn't nesseserily imply intelligence either (;--172.208.123.70 14:05, 2 October 2005 (UTC)

Eyebrows look unique, but most other creatures are so furry the eyebrow is just part of the fur

I don't think there's any, because we didn't evolved all that as a species except for parts of the brain. ? Kieff | Talk 14:47, 30 September 2005 (UTC)

I suppose your phrase was supposed to be "we didn't evolve all that recently as a species". Good point, because we are rather lonely as a species; there's just one race (contrary to popular belief) and our closest relatives aren't all that close (apparently somewhere in our evolutionary history we made a very 'close escape' somewhere). So it's only because we're so young that we haven't evolved further away from other animals. But what parts of the brain are you talking about? I thought that it was just the size (relative to our bodies) that makes our brain unique. DirkvdM 18:29, 30 September 2005 (UTC)

Thanks for correcting. And in respect to that part of the brain, see neopallium and hippocampus for instance. ? Kieff | Talk 07:32, 1 October 2005 (UTC)

The hippocampus is one of the oldest parts of the brain (according to the article), so that is nowhere near unique to humans. Your neopallium caught me off guard, but that turns out to be simply the neocortex, which is something at least all mammals have (I believe). It is indeed what sets us most apart from other animals, but, again, only because of its size. DirkvdM 18:34, 3 October 2005 (UTC)

A philosopher might say that "consciousness" could count as a body part, but the cognitive scientist would ponder what that would mean and whether or not we know enough to exclude chimps and dolphins from this category. The historian would note that this debate goes back hundreds of years, even before the theory of evolution was accepted in any form. --Fastfission 15:31, 30 September 2005 (UTC)

Here's a philosopher who certainly wouldn't utter such nonsense! :) DirkvdM 18:29, 30 September 2005 (UTC)

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

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

Do they have a belly button? (and did Adam?) Ojw 18:16, 1 October 2005 (UTC)

Now that you bring that up. Why are umbellical cords clipped and turned into bellybuttons? Is there a risk of infection? DirkvdM 18:34, 3 October 2005 (UTC)

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

Speed of light - where's the energy?

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

It turns out that the photon loses no energy when it enters glass, even though it slows down, and therefore needs no extra energy to speed back up later. For the energy of photons we generally write $E=h\nu$, and the frequency ν doesn't change when the photon enters a medium.

I can't come up for a great explaination of why the energy doesn't change, but I can think of an experiment that might make you think it's plausible: tie together three sections of string such that the middle section is a thicker, heavier variety than the first and third sections, tie the end of your Franken-string to the wall, and start moving the other end up and down to make waves. You should see that the waves slow down in the middle bit, but no one is there at the string junction slowing down and then speeding up the waves.

There's no one taking energy out at the first knot and putting it back in at the second knot, so the wave must have the same energy when it's faster in the lighter string as when slower in the heavier string. Hope that helps. — Laura Scudder | Talk 14:16, 30 September 2005 (UTC)

There's an important distinction between the 'speed of light' and the speed of the photons that make up that light. Our article on speed of light has a good explanation of this phenomenon. Essentially, photons travel a the full (vacuum) speed of light at all times. When they travel through a medium (like glass) they repeatedly run into and interact with particles (atoms and molecules in the medium)—the photons are absorbed and then reemitted. These interactions take a small but appreciable amount of time, reducing the apparent average velocity of the light through the medium.

Since the probability of these interactions varies with the wavelength (energy) of the photons, the speed of light in a medium is dependent on wavelength. This is how prisms are able to split light into a spectrum. TenOfAllTrades(talk) 14:26, 30 September 2005 (UTC)

Of course, you can have a fairly self-consistent understanding of light as waves, as long as you stick to the medium. The experiment above with strings of different weights also works in water of various depths. EM waves slow down in a medium because some energy goes into polarizing the medium, e.g. a slight shift in the electron cloud of the molecules the wave passes through. All three of these illustrate a very general concept called impedance, which has to do with the difficulty of creating the displacement/polarization that makes up the wave.

It's interesting to note that this slowing effect happens even when absorption and emission of a particular wavelength are forbidden by quantum mechanics, and so cannot be explained fully by Ten's analogy. But, as in his model, almost all of the energy of polarization is passed along to the next section of medium as the wave travels. The real brain teaser is, where is the energy stored as the photon travels through vacuum? If there's no medium to polarize, what holds the electric field? The short answer is, the photon speeds up so much that, according to special relativity, the media on either side of the vacuum appear to be touching one another from its perspective. Due to length contraction, it doesn't notice any gap at all, even a gap lightyears wide; due to time dilation, the energy is stored for exactly 0 time, therefore no medium is needed to store it.--Joel 19:31, 30 September 2005 (UTC)

A note about 'forbidden' transitions in quantum mechanics. You can actually get away with a great deal if you do it very quickly—very short-lived states have a very broad associated energy uncertainty. Joel's description fits best if you want to deal with photons as waves; the absorption/emission model works best if you want to deal with photons as particles. TenOfAllTrades(talk) 21:01, 30 September 2005 (UTC)

Educational technology companies in Boston

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

Thanks for any help!

Mary

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

CHANGES IN CHEST&LUNG VOLUME

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

THANKS

Have you read the Wikipedia article: Heimlich maneuver? --hydnjo talk 17:07, 30 September 2005 (UTC)

AND NEXT TIME COULD YOU REFRAIN FROM SHOUTING PLEASE? 

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

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

Penis Roll

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

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

Oysters and spirits fact or fiction

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

Well there is a connection in that some folks thought that the alcohol would kill any "bad" contaminants. It didn't and so started the urban legend. But on a more sober note, this FDA publication documents some potentially severe interactions. --hydnjo talk 19:22, 30 September 2005 (UTC)

That's not really an interaction. Alcoholism can cause liver disease, and liver disease increases susceptibility to Vibrio vulnificus, and oysters can be a source of Vibrio, but having a drink with your oyster causes no problems per se. - Nunh-huh 22:17, 30 September 2005 (UTC)

Correct, I did muddle interaction and susceptibility. The "urban legend" that I was referring to was the belief that if the oysters were of dubious origin then dunkin' them in spirits would rid it of Vibrio (which it didn't) and so when the ill effects occured the eater (rather than blame his poor judgement) would blame the oyster/alcohol combination to save face. --hydnjo talk 23:49, 30 September 2005 (UTC)

Supposedly oysters increase libido and liquor reduces inhibitions, it is not hard to imagine this can result in unexpected parents.

If the two of you have decided you'll sup on oysters and spirits in the first place, I suspect you're half-way there anyway.... - Nunh-huh 22:17, 30 September 2005 (UTC)

... how could you tell? Cheers, --hydnjo talk 23:27, 30 September 2005 (UTC)

Myth or not, I have eaten oysters at several restaurants which had specific cautions on the menu to avoid (much) consumption of spirits with oysters. No reasons were given. Notinasnaid 22:51, 1 October 2005 (UTC)

Urban legends do have a way of infiltrating our culture. Hey, if it's on the menu (or on the television set) it must be true. --hydnjo talk 06:09, 3 October 2005 (UTC)

tickling

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

Read the Wikipedia article Tickling and the Research section there has an explanation. --hydnjo talk 19:06, 30 September 2005 (UTC)

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

Ozone Layer

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

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

Software Chronic Crisis

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

• Set book? Notinasnaid 19:57, 30 September 2005 (UTC)

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

Mysterious Smokey Lines Around Nuclear Explosions

In many photographs of nuclear explosions I often see smokey lines off to the sides (see [4] for an example). What causes these lines and why do they happen? I've heard of the rope trick effect but these aren't cause by guy lines, and they�re visible for some time after the initial fireball.

• I believe that these are deliberately set markers, so that the effects of the shockwave on the surrounding air can be seen. See [5] for more. -- Bob Mellish 22:12, 30 September 2005 (UTC)

Thanks! I never imagined they were from smoke rockets. I always thought they were some product of the explosion themselves. --138.162.140.37 22:35, 30 September 2005 (UTC)

Butyric acid and odour of socks and blue cheese

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

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

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

• Our article on Butyric acid says it can be found in rancid butter, parmesan cheese and vomit. I don't know whether it can be secreted by smelly feet, but I live for the person with those feet if that's the case. - Mgm|^(talk) 22:29, 30 September 2005 (UTC)

Some things are agreed on: butyric acid has a very unpleasant odor, and it is butyric acid that gives rancid butter or spoiled meat their noxious aromas. Butyric acid is also found in sweat. I suspect that the smells of "smelly feet" and of blue cheese are rather complex affairs, and that the scent of butyric acid is a component of both smells, but that opinions may differ as to which scents predominate in these complex aromas (indeed, I rather suspect that the "mix" varies from foot to foot and cheese to cheese.... - Nunh-huh 22:29, 30 September 2005 (UTC)

It is plausible. Butyric acid is usually formed by the bacterial metabolism of fats, and sweat contains some fat. Physchim62 10:18, 2 October 2005 (UTC)

How does the Internet work?

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

Heart

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

You really should read the Heart and Atrium (anatomy) articles. They will will most likely answer your question. If you still have some confusion after reading the articles then come on back and we'll try to clear things up. --hydnjo talk 00:14, 1 October 2005 (UTC)

I don't think those articles actually do help much - nothing there that I can see on venous physiology. Blood is returned to the heart mostly via the deep venous circulation. These deep veins are enclosed inside contracting muscles, and contain valves that prevent backflow). Sixty percent of the blood present in the calf veins is expelled into the popliteal vein (below the knee) with a single, normal calf muscle contraction. [6]. The deep venous circulation goes into the inferior vena cava (from the legs) or superior vena cava (from above) and thence into the right atrium (from whence our articles have it covered). - Nunh-huh 02:52, 1 October 2005 (UTC)

In reading those articles I concluded that the return flow to the right atrium was a result of the pressure caused by ventricular pumping action that is, pumping blood by the action of the right ventricle into the pulmonary artery and then when it returns from the lungs through the pulmonary veins it goes into the left atrium. Then after going through the mitral valve, the blood is again pumped by the left ventricle this time through the aorta. This final pumping action results in pressuring blood flow throughout the body and returning it through the superior and inferior vena cavae into the right right atrium and through the tricuspid valve into the right ventricle and so on. This is what causes blood to flow (enter) the right atrium. That was my understanding after reading our articles. --hydnjo talk 04:56, 1 October 2005 (UTC) Strike my flawed response. --hydnjo talk 18:32, 1 October 2005 (UTC)

Then our articles are defective! The left ventricle doesn't supply the force that returns the blood to the heart. See [7], [8]. Mean circulatory pressure has no physical meaning as a driving pressure behind venous return. Normal Central Venous Pressure (though it can't be said to control venous return) is only about 2-6 mmHg. - Nunh-huh 07:23, 1 October 2005 (UTC)

Electron migration speed

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

You ask good questions<g>. This is a very complicated subject. See if this page is helpful. - Nunh-huh 02:55, 1 October 2005 (UTC)

This page (thanks Nunh-huh) is exactly what I was looking for. And also this (thanks SCZenz). My comments in the following paragraph have to do with something entirely different, I confused myself again. --hydnjo talk 19:52, 1 October 2005 (UTC)

I was inspired to ask this question from the query above: "Speed of light - where's the energy?" I think I found the answer at Current (electricity) which states that (electron migration speed) "in the near-vacuum inside a cathode ray tube, the electrons travel in near-straight lines ("ballistically") at about a tenth of the speed of light." The link above "(this page)" was also helpful but I was wondering about the speed of electron flow as a fraction of the Speed of light. That's what I was curious about. --hydnjo talk 04:05, 1 October 2005 (UTC)

Actually, I believe that in wires individual electrons are moving extremely slowly (a few cm per hour), and that the electrical signal, while much faster, still travels much slower than the speed of light. See here. -- SCZenz 06:01, 1 October 2005 (UTC)

My chemistry teacher used to quote 1mm per second, but I don't know his source for that number. Ojw 18:04, 1 October 2005 (UTC)

Capillary action and glass a couple small questions.

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

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

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

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

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

what is a medicinal plant starting with ne

Well here is a start: Ne and then on to Nee and then finally to Nel. I hope it's in there somewhere. --hydnjo talk 04:18, 1 October 2005 (UTC)

Neem is a medicinal tree. --nixie 10:40, 1 October 2005 (UTC)

Category:Herbal & fungal drugs/medicines suggests Nettle. Thryduulf 10:51, 1 October 2005 (UTC)

Time problem

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

This is a modular arithmetic problem. If it's 5:00 now, how many hours until the clock shows 05:00 the next time? Ans=24, or perhaps 12 depending on whether we're talking about a 12 or 24 hour clock. So the key is to realize every 24 (or 12) hours gets back to 05:00, so it's 05:00 24 hours later, and 48 hours later, and 72 hours later. The "in between" numbers are just like adding 1-23 hours to 05:00 but starting with a base that's the nearest multiple of 24 (or 12). What this is, is the remainder after dividing the total number of hours by 24 (or 12). 125 hours later is just like 5 hours later (remainder when dividing 125 by 12 or 24 is 5), so the clock says 10:00. -- Rick Block (talk) 04:43, 1 October 2005 (UTC)

125 = 12 * 10 + 5 (=24 * 5 + 5), so the clock will be 5 hours' ahead of its starting position, i.e. 10:00. You just have to look for convenient multiples of 24.

More generally, there's a lot like this in student math competitions, which sounds a bit like what you're doing. For example, the famous 17.5% VAT problem (take 10% by moving the decimal place, halve it to get 5%, halve that to get 2.5%, and add those 3 numbers to get 17.5%) -- it definitely pays to be sneaky and look for the shortcuts. Ojw 17:53, 1 October 2005 (UTC)

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

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

--Neutrality^talk 04:39, 1 October 2005 (UTC)

For numbers greater than 300, you have the possibilities of '3' or '4' followed by any of the remaining digits, following by one of the remaining digits again. This is 2 ('3' or '4') x 3 x 2 = 12 possibilities. For the numbers between 240 and 300, you must select '2' as the first digit, then '4' as the next digit, and then there are two possibilites for the third, so you have an additional 1 x 1 x 2 = 2 results. Total result = 12 + 2 = 14. Most such problems are just a matter of multiplying out the possibilities, but in this case the constraints meant we had to break it into two problems.-gadfium 04:55, 1 October 2005 (UTC)

In general, the number of ways to order (permututate) X different objects is is X! (the factorial of X, i.e 1*2*3*4*...*X). For instance you can order A,B,C in 3!=1*2*3=6 ways(ABC, ACB, BAC, BCA, CAB and CBA). This is because you can select the first thing in 3 ways, the second in 2 ways, and the third in only 1 way, ie. 3*2*1=6 ways total. Hope this helps gkhan 11:32, 1 October 2005 (UTC)

You can start with 2 numbers (3,4). Then you have a choice of 3. Then you have a choice of 2. 2*3*2 = 12. Then notice a couple of possibilities you've missed (241,243). Total 14.

More generally, consider how much time pressure there is. If you can count the results quicker than doing a formula, write down the answer and move on -- multiple-choice tests don't give you any marks for an elegant solution applying formulas from permutation theory, but they often do reward people who can solve 200 questions per hour with reasonable accuracy. Ojw 18:02, 1 October 2005 (UTC)

statistics

What are the limitations of Statistics?

As in what? Prediction? ? Kieff | Talk 10:56, 1 October 2005 (UTC)

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

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

Limit Definition of a Derivative

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

$m=\lim _{x\to 5}{\frac {x+{\frac {1}{x}}-{\frac {26}{25}}}{x-5}}$.

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

Please help me.

--Henry

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

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

Therefore,$\lim _{x\to 5}(1-{1 \over 5x})=1-{1 \over 25}={24 \over 25}.--Henry$

(added after edit conflict)

First off, it's not 26/25, it's 24/25 :P

It was a coupl of years since I done this, but oh well :P. You're limit definitition is all wrong. The definition of a derivative of a function f(x) is

$f'(x)=\lim _{h\to 0}{\frac {f(x+h)-f(x)}{h}}$

which becomes

$f'(5)=\lim _{h\to 0}{\frac {5+h+{\frac {1}{5+h}}-(5+{\frac {1}{5}})}{h}}$

which simplifies to

$f'(5)=\lim _{h\to 0}{\frac {24-5h}{25-5h}}$

Cheers gkhan 07:43, 1 October 2005 (UTC)

There are two definitions of the derivative. You've each written one of them. -- SCZenz 19:25, 2 October 2005 (UTC)

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

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

TV on the computer monitor

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

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

You can't do it without a peripheral card in your PC that accepts your television standard. Right now the TVs that can also serve as computer monitors cost more than bottom of the line PCs. You won't save any money at the moment. This is not an accident. Ancheta Wis 11:38, 1 October 2005 (UTC)

If you already have a video card that will accept Video/Sound Out (or even SCART) somehow, it would just be a matter of connecting it to the right outputs on the cablebox. Have I missed something here?--inks 23:48, 1 October 2005 (UTC)

There is something called an LCD TV which will accept TV connections. If your video card has RCA/S-video in then you can get limited TV support. Your best bet is getting a TV tuner card, they can usually found for about 30-40$

Normalization of scale

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)

• Planets!!! Rofl, what is the question?--172.208.123.70 13:54, 2 October 2005 (UTC)

what is dsl?

I suppose you mean Digital Subscriber Line? ? Kieff | Talk 16:40, 1 October 2005 (UTC) Also, in urban slang the acronym can be used to describe "dick sucking lips" -Drdisque 20:42, 1 October 2005 (UTC)

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)

• Bromine or iodine. Physchim62 10:23, 2 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 [9] 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.) [10] - 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

Xenon

What are the main properties of 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)

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: [11]. It gets your Product Key and even lets you change it if you want. It works on all versions of Windows. Enjoy. --pile0nades^{talk | 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

• See Dental fillings. --jpgordon∇∆∇∆ 20:37, 2 October 2005 (UTC)

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 $x\in (-1,1)$. Now, then, first it'll help to split up the problem as follows:

$ln({\frac {1+x}{1-x}})=ln(1+x)-ln(1-x)$

Now we'll work on the second term, and later get the first from it. First, note that

${\frac {1}{1-x}}=1+x+x^{2}+x^{3}+...$

(To see this, just multiply both sides by 1-x.) Now integrating both sides from 0 to x gives:

$-ln(1-x)=x+{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}+{\frac {x^{4}}{4}}+...$

From this, replacing x by -x, we get

$ln(1+x)=x-{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}-{\frac {x^{4}}{4}}+...$

Which going back to the first equation gives

$ln({\frac {1+x}{1-x}})=(x-{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}-{\frac {x^{4}}{4}}+...)+(x+{\frac {x^{2}}{2}}+{\frac {x^{3}}{3}}+{\frac {x^{4}}{4}}+...)=2(x+{\frac {x^{3}}{3}}+{\frac {x^{5}}{5}}+...)$

Hope that helps! -- SCZenz 20:40, 2 October 2005 (UTC)

ATP (adenosine triphosphate)

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

Try letting y = x - π, then using sin(x) = sin(y+π) = sin(y)cos(π)+cos(y)sin(π) = -sin(y). Then do the usual expansion about y=0, and substitute back in what y is. Does that work? -- SCZenz 23:15, 2 October 2005 (UTC)

When in doubt, you can always go back to the most general definition of a Taylor expansion near x = a:

$f(x)=f(a)+f^{\prime }(a)(x-a)+{\frac {1}{2}}f^{\prime \prime }(a)(x-a)^{2}+\ldots {\frac {1}{n!}}f^{n}(a)(x-a)^{n}+\ldots$

Notice that this expansion is what you want for a = π and f(x) = sinx. Then

$f(\pi )=\sin \pi =0$

$f^{\prime }(\pi )=\cos \pi =-1$

$f^{\prime \prime }(\pi )=-\sin \pi =0$

$f^{3}(\pi )=-\cos \pi =1$

$f^{4}(\pi )=\sin \pi =0$

Now we can see a pattern: these values of the derivative will simply repeat, and the Taylor series will be:

$\sin x=-(x-\pi )+{\frac {1}{3!}}(x-\pi )^{3}-{\frac {1}{5!}}(x-\pi )^{5}+{\frac {1}{7!}}(x-\pi )^{7}\ldots$

Which matches exactly the expansion of -sin(x - π), which is what you get with SCZenz's method. — Laura Scudder | Talk 23:34, 2 October 2005 (UTC)

glass that shifts from translucent to transparent?

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? --[[User:Revoluci�n|Revoluci�n]] ([[User talk: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 [12].-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:

$a^{2}+b^{2}=c^{2}$

Since c is the length of the diagonal (or the hypotenuse of the triangle inside the square), and a = b (because they are sides of a square), we can say:

$a^{2}+a^{2}=12^{2}$

$2(a^{2})=144$

$a^{2}={\frac {144}{2}}=72$

We could find the square root of 72 to find the side length of the square, but keep in mind that the area of the square is simply the side length squared. Therefore, the area of the square is 72. splintax ^(talk) 03:49, 3 October 2005 (UTC)

Hair texture

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

Did you read Hair? This quote may be helpful:

The diameter of a human hair ranges from about 18 µm to 180 µm. In people of European descent, blond hair and black hair are at the thinner end of the scale, while red hair is the thickest. The hair of people of Asian descent is typically thicker in diameter than the hair of other groups.

Cross-section shape of human hair is typically round in people of Asian descent, round to oval in European descent, and nearly flat in African peoples; it is that flatness which allows African hair to attain its frizzly form. In contrast, hair that has a round cross-section will be straight. A strand of straight round cross-section hair that has been flattened, for example, with an edge of a coin, will curl up into a micro-afro.

Hope that helps, although it doesn't answer your question completely. splintax ^(talk) 03:51, 3 October 2005 (UTC)

Now there's a nice eurasian-centric way of putting the question. Ever heard of the out of Africa theory? I assume we all had nappy hair once upon a time, but those who left Africa somehow lost that (I don't know why, though, sorry). Note that pubic hair also curls because it is flat. One might conclude that blacks have pubic hair on their heads, but it would make more sense to say the rest of us still have nappy crotches :) . DirkvdM 14:11, 3 October 2005 (UTC)

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

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)

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)

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.

Thank you in advance.

Seems like a normal excercise pain to me. I'm pretty sedentary myself, and I get the same simptons whenever I ride a bike for a few kilometers or play soccer for an hour or two. But I'm no physician, so remember Wikipedia:Medical disclaimer. ☢ Kieff | Talk 11:36, 3 October 2005 (UTC)

A medical discalaimer on Wikipedia?? Get real! Anyone who thinks that Wikipedia can serve as a substitute for a physycian really needs to see a doctor - just of a different kind :) . DirkvdM 14:41, 3 October 2005 (UTC)

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

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

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>

You shouldn't put your email on this page, as everyone in the world will read it and send you spam. Replies will be posted on this page, not to your email address.

Probably this means that every gas well should be on a piece of land of twenty acres without another well on it. Givng the separation this way allows for easy calculation of how many wells you can put on a piece of land. DJ Clayworth 15:45, 3 October 2005 (UTC)

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)

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 [13] 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)

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

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?

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)

Q about astronomy

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)

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)

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)

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)

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)

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 Zeland and Austrlia trying to find the answer to this ?.I have found nothing anywhere!I want to know how it breaks down chemically,amounts in blood verses 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.

Search medline for heroin overdose like this [14]. 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)

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)

math

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

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

ABOUT BULLSEYE NETWORK VIRUS

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: [15].

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)

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 $l$ in the vector (my C++ is very rusty, but isn't that the length method of the vector class)?
2. Generate a random number $i,0\leq i<l$ with a pseudo-random number generator.
3. Access the i'th object in the vector (either with operator[] or the at method, which is range-checked.

The choice of which pseudorandom number generator to use depends on your application. If, for some reason, it is important that an attacker not be able to predict which element will be selected next based on the elements selected previously, you need a cryptographically secure pseudo-random number generator, otherwise any modern generator, including the one in your system library, will probably do (though I prefer to use the Mersenne twister for all my own simulation work because it's both good and fast).

If you want a guarantee that you won't get repeated elements, then a shuffle is probably the best way to go. But here's a basic performance tip; if your objects are large, create a vector/array of pointers to them and shuffle the pointer array rather than the objects themselves.

As to the interface, surely you could define a subclass of vector which adds a "ranelement" method that implements the procedure I've described above? --Robert Merkel 01:00, 6 October 2005 (UTC)

OH. I get it now. Red wants to access an element at random. Yes, that solution is the one that first comes to mind. I don't think there's a simpler method... Dysprosia 09:31, 6 October 2005 (UTC)

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)

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)

Dance Pads Sales

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

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,
<removed e-mail address>

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

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.

Thank you for your replies in advance.

Eqbal Vakilzadeh

Plants, like other forms of life, are adapted to fit certian circumstances. Not all trees are the same.

It is not just about adaptations. Obviously mangroves do live in brackish water. They have several adaptations to allow this. High quantities of salt in their cells that means water can move from the brackish water to the even saltier mangrove cells by osmosis. This would not be possible for regular trees as you suggest above. mangroves also have air tubes in their roots specifically to get the oxygen down to the tissues under water. You're right that hypoxia this is a very real problem for trees that live in standing water.

With respect to the islands, the key is that the ground water can push out the sea water. This web site has a diagram and description [16]. 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?

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

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)

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)

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)

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)

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)

• Seems to be that or the Queen Mary II. --jpgordon∇∆∇∆ 03:53, 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)

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)

Atoms and molecules

• In the absence of a specific question, I would suggest our articles on Atom and Molecule. Capitalistroadster 04:23, 6 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)

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 = 12m. --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.

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)

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)

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)

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)

Regarding Heads

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

Should be fine in theory.

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

I'm not sure it would be that difficult in practice, certainly a non-trivial proposition, but given the success of primate head transplants, I would think that simply keeping a human (I presume that the questioner is talking about humans) head alive would be well within the current state of the art. The major obstacles to actually doing this would be ethical, not medical.

Funny that only a brain transplant is also called a whole body transplant. The same could be said for a head transplant I'd say. Also funny that the article on the former nevertheless goes on to speak about tranplanting the brain to another body. The alternative name exists for a reason (if one assumes personality resides in the brain). DirkvdM 20:40, 6 October 2005 (UTC)

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

word password recovery

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

Elements

What is the importance of Iron?