Wikipedia:Reference desk archive/Science/2006 August 1

From Wikipedia, the free encyclopedia

Humanities Science Mathematics Computing/IT Language Miscellaneous Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions at one of the pages linked to above.

< July 31 Science desk archive August 2 >


Contents

[edit] The evolutionary value of doing calculus?

Human beings evolved to survive, but why did we evolve the ability to do calculus?

I do not understand why humans can do so many clever things that are quite unnecessary for survival. Surely evolution is parsimonious and abilities that are of no value to surviving in the savannah environment should never have been developed? --62.253.44.34 00:18, 1 August 2006 (UTC)

Human evolution#Use of tools? Melchoir 00:26, 1 August 2006 (UTC)

There isn't a gene for being able to calculus. Rather, doing calculus comes naturally (with some training) to any human with a firm grasp on symbols, the concept of reducing complex problems to tiny steps, and a few other basic skills that definitely have evolutionary value. StuRat 00:40, 1 August 2006 (UTC)

I think the questioner was trying to ask why intelligence evolved in humans, and used calculus as an example. --Bowlhover 03:31, 1 August 2006 (UTC)
Intelligence is a major advantage! It allows humans to solve difficult problems, use tools (as noted by Melchoir), comunicate effectively, resolve conflicts nonviolently, waste time on the computer :), and many other things. The ability to do calculus is just an extension of the ability to do arithmetic and count, albeit a pretty big extension. Emmett5 04:01, 1 August 2006 (UTC)
There's actually a stub at Evolution of intelligence that needs work, if people here are interested. --Allen 04:25, 1 August 2006 (UTC)
I added to it. StuRat 21:48, 5 August 2006 (UTC)
(Warning: this opinion is very biased and discriminating. Don't take it entirely seriously.) I don't think humans have ability to do calculus genetically coded in them. Humans have evolved such that they could comprehend more and more abstract thoughts and plans (symbols, as StuRat says), and as they also learnt how to count, the ability to do algebra came naturally. Caluclus, on the other hand, is not like that. Most people don't understand calculus instinctively but have to be thought rules of calculus written in the language of algebra. The basis of calculus were invented by a few brilliant mathematical geniuses who did have a calculus instinct by fluke, e.g. Newton and Leibniz (real calculus), Euler (complex analysis). Once they wrote the foundations of a theory in the language of pure mathematical formulas, others could derive new results in calculus by manipulating the prior results using the rules of algebra. – b_jonas 12:58, 1 August 2006 (UTC)
FYI Norbert Weiner as a child prodigy and after learning algebra, invented the calculus only to discover it had already been invented. (He entered college at age eleven.) This implies something; I'm not sure what. -Wfaxon 23:57, 8 August 2006 (UTC)
It implies that it's a real thing, not just something silly somebody made up (like most of psychology, for example). It also implies he should have spent a bit more time studying existing theory before developing his own. StuRat 01:39, 9 August 2006 (UTC)
I was thinking more along the lines that at the turn of the 18th century you needed mature world-class geniuses to invent the calculus; at the beginning of the 20th century all you needed was genius. Either that or the way that algebra was taught in 1900 itself implied the calculus since the authors of the algebra texts Weiner learned from certainly knew it. BTW one really shouldn't be too critical of a nine-year-old's lack of research back then: No internet! -Wfaxon 04:21, 9 August 2006 (UTC)
"Years of laboratory research have saved me from having to spend hours doing research at my local library." StuRat 18:26, 9 August 2006 (UTC)
The nice thing about general intelligence is that it is very flexible—you're not locked into one adaptionary box. That makes it a tremendous evolutionary advantage when you are a species that is not terribly fast, strong, or with acute senses relative to the sorts of predators around you. It also means that you can migrate with relative ease and don't have to wait hundreds of generations to develop (or lose) a shaggy coat. ;-) --Fastfission 12:50, 1 August 2006 (UTC)

I used calculus as an example of intelligence. Although we take our intelligence and the man-made world for granted, I think it is very odd that it evolved at all and we can do all these things. Its as if an earthworm had somehow evolved the ability to run at 60mph - it doesnt need it to survive in its environment, so the ability to run at 60mph should never have evolved. Yet in humans this is what has happened - you dont need much intellect to survive (other animals get along without it) yet somehow we have developed this intellect and ability to do things such as eg calculus which natural selection has played no part in. How? Why?

I've heard a couple of differing opinions on what the evolutionairy advantage of our intelligence is. Some propose that our ancestors required enhanced cognitive abbilities so they could better use the tools they had. One particulair example I liked was how ancient humans might have had to use their brain to figure out the trajectories the rocks they threw would take. It could also be a result of the tight social groups we form. Being able to accurately communicate with your fellow man would be a big advantage (and this would require some decent brain power).
Whatever the basis of our smarts may be, you should remember that we haven't stopped evolving. Things like calculus, rocket science, chemistry, sudoku puzzles and Barney the dinosaur all fill a niche in our society and thus are not without purpose. So our ancestors did not do calculus because it didn't have any use to them, being able to hit a gazelle at 50-100 yards away did and from these humble beginnings the rest followed. -Pascal

The answer is that we did not evolve the ability to do calculus, or mathematics in general — that's why we are so incredibly bad at it. Consider the fact that even quite simple computers, like the one on your desk, can outperform humans in basic arithmetic by a factor of about a U.S. billion (that's 109), but have enormous trouble with tasks like, say, speech recognition, or catching a thrown object, which we did evolve for. Our ability to do any mathematics at all is basically a side effect of us having evolved, for other reasons, enough abilities for abstract thought to — barely — allow universal computation. That means we can, in principle, do anything a computer can do; it doesn't mean we can do so in any reasonably efficient manner. To use a programming analogy, all our conscious thought processes happen at an extremely high level, far from the hardware — indeed, the fact that they are subject to conscious monitoring implies that. We have efficient low level primitives for all sorts things that are useful for survival in nature, but for things we didn't evolve such primitives for, we need to rely on high-level processes that are extremely inefficient, since they are built upon systems that weren't designed for such use at all. —Ilmari Karonen (talk) 22:19, 1 August 2006 (UTC)

Nice analogy, Ilmari; thanks. I'd never thought of it like that. --Allen 04:52, 2 August 2006 (UTC)
Consider, for example, our skills at language. Noam Chomsky's famous hypothesis is that there is a kind of language gizmo in the human brain that can learn any language, because it carries some sort of pre-prepared algorithm for verbal communication. But extensive research seems to suggest that their is no such thing as a central language processor in the human brain. Rather, language processing is distributed all over the brain: when a illiterate child looks at words, activitiy is seen in several regions in the rear part of the brain; when they listen to words, their brain shows activity in an area in its center; when they speak nouns, activity occurs in a different area of the central brain, nearer the top; when they speak verbs, activity occurs in two separate areas, one nearer the front, the other nearer the back.
In 1861, when Paul Broca discovered significant damage to an area of the brain (now called Broca's area) while doing an autopsy on a patient with a verbal disability, observers worldwide thought he might have discovered something very significant. Broca's area is on the left side of the brain, near the front; damage there will cause sufferers to speak haltingly, and mostly in nouns; they generally understand others who speak to them, and realise that they are unable to speak. Broca's patient, Leborge, was nicknamed 'Tan', because it was one of a handful of words he could say. Carl Wernicke made a similar discovery, in an area now called Wernicke's area. Wernicke's area is also on the left side of the brain, but further back. Sufferers of damage in Wernicke's area can speak fluently, but their speech is essentially a randomly assorted jumble of words.
What this shows is that our linguistic skills are not a discrete brain function. Rather, they are an aggregate of dozens, possibly hundreds of more basic skills that may have been evolved for very different reasons, such as hunting, scavenging, or tool making. Math is probably the same way. One of the most remarkable features of the human brain is its 'plasticity', or ability to rewire itself to perform completely new tasks. The most remarkable example of this is a woman who had a stroke that caused massive damage to the left hemisphere of her brain. For some time, she was unable to read, until she was coached into using her right brain to interpret symbols. She completely rewired her brain to have a totally different approach to symbols; she went from a scientific, logical approach to the interpretation of the alphabet to seeing them as an artist. Likewise, people who are talented with math have brains that have assembled basic, simple functions into a more complex skill. It is like a computer rewriting its own software to use its basic functions in a totally new way.
Hope I've helped. Ingoolemo talk 22:53, 1 August 2006 (UTC)

By the way, this is precisely the debate between Darwin and Wallace. Wallace argued that natural selection would have only had to make humans a little smarter than other big apes currently are in order to have an unbelievable evolutionary advantage, and didn't believe there was any reason for a "savage" to develop a conscience or complicated moral sensibility, much less high intelligence. Darwin countered with his theory of sexual selection, arguing that bigger brainpower might have been related to impressing females, in the same way that a peacock's feathers serve no functional purpose outside of being attractive to the ladies. Wallace never bought into that, though (it probably didn't help that he was left at the alter—he never could accept the idea that female mates were in charge of choosing attractive mates), and instead went the direction of thinking that a conscious spiritual force had guided human evolution into its present position. Darwin was understandably horrified and wondered if Wallace hadn't "murdered" their "child". --Fastfission 04:39, 2 August 2006 (UTC)

[edit] Donna Nook

As the Donna Nook fire range has been used by A-10 Thunderbolts for cannon practice and the A-10s have a GAU-8/A Avenger Gatling gun, which indeed fires depleted uranium armor-piercing shells, is there any publicly available information on the health risks associated with the place? Does anyone know whether the Freedom of Information Act could be used to request information from the MoD or is it not applicable? Thanks, E Asterion u talking to me? 00:35, 1 August 2006 (UTC)

[edit] Basic Burn Question

I looked on web md, but they skirted the question. I just got a minor burn by grabbing a hot pan. It's been two or three days and the small burn has turned into a small raised blister that doesn't hurt at all unless put under particularly hot water. The raised blister's really irritating me, and i was wondering if after three days, the skin has formed underneath the scab sufficiently for me to pop it, let the liquid out, and peel off the scab to let the new skin heal over. If not, when, if ever, is this a good idea? Should I never pull the scab off, because it seems to me that that scab is not what's going to become my new top skin layer. Thanks. Sashafklein 05:57, 1 August 2006 (UTC)

My understanding is that as long as there's fluid in the blister, the flesh beneath is vulnerable. All the literature I've read says never to pop blisters, so I ice them, which decreases the fluid pressure and makes them less irritating. Technically you're not supposed to apply ice directly to burns, but you're not actually applying it to the burn, you're applying it to the blister. Also, even after several days the application of cool can have anti-inflammatory benefits. Also, cover the blister with a bandaid or a loose dressing to keep it from bursting or being bumped.--Anchoress 07:01, 1 August 2006 (UTC)
Actually, when you burn your skin the best thing to do is to cool it down with warm water (not hot of course, but about body temperature). This makes it hurt more at that moment, but it will prevent a blister from forming and thus reduces pain later on. At least, I heard this once and tested it on one occasion, and in my case it worked. DirkvdM 12:24, 1 August 2006 (UTC)
I hadn't heard that warm water is better than cold, I'd just heard that ice isn't good for burns. But we're talking about a 3 day old burn here, IMO ice is better.--Anchoress 18:24, 1 August 2006 (UTC)

Thanks. Should it just eventually deflate or peel off? Sashafklein 07:05, 1 August 2006 (UTC)

Yeah, it'll either deflate or end up getting punctured on its own. If the latter happens you should wash it very carefully and put some antiseptic (e.g. Neosporin) on if you have it, and probably a bandage, to prevent infection. I've done this an embarrassingly high number of times (something about the way my toaster is made seems to encourage me to burn my fingers trying to get things out of it). --Fastfission 12:48, 1 August 2006 (UTC)
BTW Neosporin isn't an antiseptic, it's a topical antibiotic.--Anchoress 18:24, 1 August 2006 (UTC)

I've been a burn surgeon for many years and this is my advice: The fluid in a burn blister is clean, but not sterile and eventually will get infected. As long as the blister is intact, the burn wound is protected and relatively painless. If these blisters are small and do not interfere with function (e.g. not over a joint, or so large that they compress the circulation to a body part) then I leave them alone for 1 - 2 days. If it starts to get red, indicating infection, they need to be removed and topical antibiotics applied. If there is suspicion that the burn is fairly deep, then I remove the blister so that it can be inspected on a frequent basis. If there is any doubt, you should see a burn specialist ASAP.

BTW, cold water applied within seconds of a superficial burn will tend to lessen the degree of injury - but it must be done RIGHT AWAY. Best of luck. --Ronbarton 21:35, 6 August 2006 (UTC)

[edit] Diff. b/w university and college

my question is wat is the difference b/w university/college..and university/ institute or college/institute??

The common-usage meaning and specific definition varies somewhat with country. College would be a good start. DMacks 07:28, 1 August 2006 (UTC)
If you tell us which country you are from, we might be able to be more specific regarding the use of the words college and university. However, academic institutes tend to be research orientated, while colleges and universities will offer teaching as well as research. Rockpocket 07:53, 1 August 2006 (UTC)
"Institute" is a term which generally has a lot of flexibility. The Massachusetts Institute of Technology is basically a university, while the Institute for Advanced Study is more like an academic think-tank. The terms "university" and "college" are more specifically defined in the United States than is the term "institute". --Fastfission 12:43, 1 August 2006 (UTC)
Ever been to a university? They have many colleges.
Maybe in your country. In Australia, a college is either a tertiary learning institution of lower status than a university, or the last 2 years of high school. Universities here don't have colleges within them, as far as I know. JackofOz 14:12, 1 August 2006 (UTC)
In the UK, "college" is used sometimes to mean a further education institution of lower status than a university; sometimes as a synonym for university, and for some universities, including the most prestigious, a university is divided into semi-autonomous colleges (see e.g. King's College, Cambridge). Some colleges are called schools (see e.g. London School of Hygiene & Tropical Medicine) but nobody ever uses the term "going to school" to refer to further education (this is a significant difference of usage with the US). Notinasnaid 15:05, 1 August 2006 (UTC)
Want more confusion, see the article about the University named the College of Charleston. It can't even decide what it is! Well, it was a college that gained university status and decided to keep the old name for the undergrad and only change to University of Charleston for graduate courses. --Kainaw (talk) 14:57, 1 August 2006 (UTC)
Maybe a university that's named "College" would be a good place to go after attending Baltimore City College, which is a high school. DMacks 16:39, 1 August 2006 (UTC)

And in England, of course, Eton College is just a public school for 13-18-year-old boys. Some university colleges have associated schools: Magdalen College, Oxford and Magdalen College School, Oxford, comprise such a pair.--G N Frykman 17:18, 1 August 2006 (UTC)

In the U.S. there are similarly several University High Schools associated with Universities. Rmhermen 01:05, 2 August 2006 (UTC)
(edit conflict) In the UK there are plenty of schools called colleges (though then are often private schools - and to confuse matters further, they call them public schools - e.g. Fettes College). There are also sixth form colleges, which are further educational establishments, as well as higher educational establishments, called colleges. I have never heard of an UK academic institution that teaches though, and neither have i heard of a British university be anything other than a higher educational establishment. I await correction on this. So the bottom line, i think, is that college is a term that can cover a lot of different educational establishments, but university and institution are more precise (though there are possible exceptions). Rockpocket 17:28, 1 August 2006 (UTC)
The Institute Of Education is part of London University, and teaches teachers.
In the U.S., generally a stand-alone college is more narrow in scope than a university, which includes several divisions usually called "colleges." For example, I graduated from the College of Arts and Sciences at the University of Oklahoma, although I took courses in other colleges (e.g. a course in the College of Business). A stand-alone college may be as rigorous as a university, or it may be less so, as is the case for community colleges, junior colleges, and (at least some) for-profit colleges. --Ginkgo100 talk · contribs · e@ 19:58, 2 August 2006 (UTC)

[edit] ADHESIVES

WHAT IS THE BEST ADHESIVE TO BE USED BETWEEN RUBBER AND POLYURETHANE, TO PREVENT PRESSURIZED WATER TO COME BETWEEN. WALEED KHAMIS

Please don't shout. DirkvdM 12:27, 1 August 2006 (UTC)
You want something like an acrylic resin that will turn into a hard polymer in the presence of water. Luckily, that is what Super Glue is. How stiff do you want it to be? Super Glue gets very hard, so the rubber won't be flexible. (Oh - and don't shout!) --Kainaw (talk) 14:54, 1 August 2006 (UTC)

[edit] Communication equipment

I'm doing research on Euipment used in Communication.please help!!--198.54.202.146 08:54, 1 August 2006 (UTC)Sizwe—

Does Telecommunication or Category:Telecommunications help? Melchoir 09:05, 1 August 2006 (UTC)

What kind of equipment?

What kind of communication?--Shantavira 18:20, 1 August 2006 (UTC)
Is this a communication breakdown? Try to communicate your problem to us. DirkvdM 19:30, 1 August 2006 (UTC)
I agree. They needed to be more specific. --Proficient 20:36, 5 August 2006 (UTC)

[edit] Overlapping of orbitals

Whether S-S overlapping takes place only in the formation of Hydrogen molecule? Are there any examples for such type of molecules in which S-S overlap takes place? —The preceding unsigned comment was added by Vamsi mahathian (talk • contribs) .

I assume by "hydrogen molecule" you mean H2, so there's also H3+. Also consider the alkali metal hydrides. DMacks 16:29, 1 August 2006 (UTC)

[edit] Starching a Battledress?

Does anybody know why on the label of US made True-Spec BDU trousers it is written that you should not starch them? I have heard a military urban myth that starching your battledress makes it easier to see you using night-vision equipment. Can anybody deny or confirm this claim? Thank you for your time. Mieciu K 13:46, 1 August 2006 (UTC)

Standard military issue night-vision equipment works in either of two ways
  1. By taking in the low amount of photons and magnifying the light so you can see on a little screen
  2. Infrared radiation intensity is mapped, with different colors denoting different temperatures.
I don't know what the starch is that you use for washing is made of (perhaps starch?). If it is starch, I would think that the infrared radiation nor the visible light intensity would be had a more than negligible effect on.
Unfortunatly the label on the bottle of liquid (laundry?) starch dosen't specify what is the content of the starch that I have used, but I presume it was vegetable starch. Mieciu K 14:21, 1 August 2006 (UTC)
My experience with night-vision in the Marines is that a moonlight scope (which amplifies the visible light available) gets a bit of a reflection off smooth surfaces. If you overly starched your uniform, it is possible to get a reflection off the smooth surface. But, that is not likely. Infrared, on the other hand, did pick up on guys in newly starched uniforms better then those with unstarched ones. At the time, it was DI's and recruits. The DI's have heavily starched uniforms. I could see them much better than the recruits who were in wrinkled and dirty uniforms. Just to throw a wrench into the works - this was with the old uniforms. The Marines use a different material and pattern now. --Kainaw (talk) 14:47, 1 August 2006 (UTC)
Doesn't starch show up fairly vividly under ultraviolet light? Perhaps the idea is to make sure you don't stand out in a nightclub. --LarryMac 19:07, 1 August 2006 (UTC)
Yeah, that's what I thought, it might be a mixup with the reflection by blacklights. But that's caused by optical brighteners in laundry detergent residues. DirkvdM 20:11, 1 August 2006 (UTC)

Of course, it's also a bad idea to starch battle clothes for other reasons; stiff clothing is more likely to make noise, giving away your position, and cause abrasions, which may then become infected. Quite a stupid way to be injured on the battle field, isn't it ? StuRat 02:10, 2 August 2006 (UTC)

Are there clever ways to get injured? DirkvdM 07:14, 2 August 2006 (UTC)
No, but there are ways to get injured thru no fault of your own. StuRat 05:23, 3 August 2006 (UTC)
i was told in the NZ Army the fabric has IR absorbing dye in it. maybe the starch displaces or otherwise interferes with this? Xcomradex 08:30, 2 August 2006 (UTC)

I wonder if starch might have a negative effect on the marginal CBW resistance of the uniform?

[edit] Make Your Own Starch

Can you make your own clothing starch from the stuff at the surface of a pan of boiling potatoes? --130.161.135.31 14:38, 1 August 2006 (UTC)

Yes, that is how starch used to be made. However, I believe potato starch turns black as it oxidizes. So, you will want to experiment with the starch from other vegetables. --Kainaw (talk) 14:50, 1 August 2006 (UTC)
Try drying the goop from atop a pot of boiling rice. I vaguely remember doing this in elementary school to make starch. Nrets 15:32, 1 August 2006 (UTC)
Just Google "make your own starch" (use quote marks), e.g. "You can make your own starch by mixing 2 teaspoons of cornstarch with 1 litre of water." Other hits do include potato receipes.--Shantavira 18:23, 1 August 2006 (UTC)
Wow, you can make starch with starch? DirkvdM 07:16, 2 August 2006 (UTC)
It seems so. o.o--Proficient 20:37, 5 August 2006 (UTC)

[edit] Hub Gears

My bike has hub gears but I have to stop pedalling in order to change gear - is this a common feature of all hub gears or are mind just dodgy? Would I damage the bike if I changed the gear but carried on pedalling forward? And why is the hub physically unable to change gear unless I stop pedalling? --130.161.135.31 14:35, 1 August 2006 (UTC)

You should only have to stop pedalling for a split second (not at all if you're lucky). Yes, it is perfectly normal.

Have you looked up Sturmey-Archer? With such gears it is normal to stop pedalling while changing. At traffic lights, you might even have to back-pedal in order to change gear before setting off.--G N Frykman 17:12, 1 August 2006 (UTC)

If you just slow the pedals down a bit you should be able to change gear without actually stopping the "flow". Even with the other type of gears (which I can never spell) it's not a good idea to apply much force to the pedals while you change gear as this puts unnecessary strain on the mechanism.--Shantavira 18:27, 1 August 2006 (UTC)
I love hub gears and hate derailler (sp?) ones. I would be interested to know if there is now another company making hub gears since Sturmley Archer went out of business, as you cannot buy new hub geared bikes in the UK (except for a very heavy dutch town bike I think). The only hub geared bikes here are very very old ones. --81.104.12.138 20:50, 1 August 2006 (UTC)
Back-pedalling to change gears before traffic lights? I haven't used a gear bike in years, but I don't remember having to do that. Then again, maybe I anticipated the lights and changed gear before coming to a standstill. However, the hub gear article says "The other main advantage is that the gear can be changed when the bike is stationary, which makes them suitable for riding in city traffic with lots of stops and starts." DirkvdM 07:50, 2 August 2006 (UTC)
A geared bike is like a manual transmission car. On a car to change gears you use the clutch to disengage the engine from the transmission and then change which gears are engaged. On a bike, since the pedals only work one way (forward) and freewheel the other direction, you can effectively disengage the gears from the rear wheel by pedaling slower than the gears are turning. This allows you to switch without placing major stress on various components (as would be the case if you tried to slam a car in gear without using the clutch). Since derailleur type depend on the chain to ride itself to a new sprocket it needs be moving a little.72.1.70.58 13:14, 8 August 2006 (UTC)

[edit] Homework Questions

Q1) You are running a fermentation using anaerobic bacterium 'Megasphaera elsdenii' for the production of hexanoic acid using glucose as a carbon source.

(a) Assuming the hexanoic acid is a growth-associated product, draw a sketch graph of the relative concentrations of glucose, hexanoic acid and biomass with time for a batch culture. Explain what is happening at each stage of the fermentation. (b) What calculations would you use to determine the efficiency of this fermentation in regard to the conversion of substrate to product, and the speed of production of the product? (c) You need to increase the efficience and speed of the production of hexanoic acid. What environmental factors would you consider changing to achieve this? i'm guessing that the answer for this is temperature and possibly pH


Q2) You have been given the task of removing the particulates from a fermentation broth, prior to extraction of the product from the liquid. (a) i) Describe the structure and principle of operation of one type of filter you could use at production scale. (ii) If you found that you were unable to achieve a suitable filteration rate, what other methods of particulate separation would you test? (b) Describe one method for the drying of fermentation products, and state whether it is suitable for a heat-labile product or not. –--81.154.224.133 15:04, 1 August 2006 (UTC)

Since you failed to see the big link for posting a question at the top of this page, you probably missed the note telling you to do your own homework. --Kainaw (talk) 15:36, 1 August 2006 (UTC)
Try reading the relevant articles, then come back here if you have an actual question, in your own words, about something you don't understand.--Shantavira 18:31, 1 August 2006 (UTC)

[edit] Black hole A partial balck body

As far as i have read ,it says that a perfect black body is somthing that can absorb as well as EMIT every possible radiation????? in that case why is black hole not a partial black body?????????--59.178.2.243 15:14, 1 August 2006 (UTC)Harshita Gupta

Did you read black body and black hole. Perhaps you want to create a new article (and a whole new area of science) for partial black body. Hey, my body absorbs some radiation. Am I a partial black hole? --Kainaw (talk) 15:43, 1 August 2006 (UTC)
I have never encountered this term "partial black body". I take it to mean anything that isn't a perfect blackbody or a perfect mirror! In theory a blackbody can emit radiation of any frequency. The frequency of radiation emitted depends on the temperature of the blackbody (there is a nice graph of this in the black body article. As the temperature of a black hole is determined by the black body radiation temperature of the radiation that comes from it, it is possible to determine that the temperature of any observable black holes (as opposed to theorised sub-atomic ones) would be extremely close to absolute zero (~.00000001-.00000000000000000001K). This is why they don't emit every possible radiation.
Ummmm.... no. See the black hole article, the temperature of black holes is roughly 2.73 K, the same as the background temperature of space. Dan 15:02, 10 August 2006 (UTC)

[edit] Chronic wounds and maggot therapy

Good day,

I wish to know:

1. what are the sickness/dieases/injures would cause chronic wounds / necrotic(dead) tissue?

2. what are the sickness/dieases/injures would cause chronic wounds / necrotic(dead) tissue, but not recommend to apply Maggot Dbridement Therapy(MDT) treatment?

3. Are there any reports stated that MDT treatment fail to deliver successsful wounds healing？

4。 Are there any reports stated that MDT treatment tansforms chronic wounds worse?

Thank you very much.

Please take a short amount of time to familiarize yourself with the instructions at the top of the page. We're pleased to help out with most questions, but I'm afraid that we have to ask you to Do your own homework. If you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers. TenOfAllTrades(talk) 16:16, 1 August 2006 (UTC)
Here is a good place to start [1]

[edit] Elephants and such

is it true that the elephant population has tripled in the last month?--Nulity 16:19, 1 August 2006 (UTC)

Now that you mention it, I guess it did. We had zero elephants in Charleston before last month. Now, there are three times as many elephants in Charleston. --Kainaw (talk) 16:26, 1 August 2006 (UTC)
Lets see.... The elephant gestation period is about 22 months. Lets assume about 50% of the elephant population is female. Even if every female was pregnant at once and gave birth in the last month (and assuming there was no elephant deaths) then the population would simply have increased by a factor of 0.5. For the population to have tripled, every female would have had to have had quadruplets in the last month. According to this source [2] "Twins are very rare in elephants" and the ones in captivity in Bangkok "may have been unique". Therefore the chances that there has ever been elephant quadruplets seems highly unlikely. Given this, the answer to your question should be obvious. Rockpocket 17:44, 1 August 2006 (UTC)
For those who don't get it, last night Stephen Colbert did a segment on Wikipedia for The Colbert Report. He urged viewers to rewrite truth by editing a few Wikipedia pages, and Elephant was one of them. Melchoir 19:30, 1 August 2006 (UTC)
Unfortunately it appears our article THE_NUMBER_OF_ELEPHANTS_HAS_TRIPLED_IN_THE_LAST_SIX_MONTHS! was recently deleted. And protected against recreation due to a number of re-creations. Weregerbil 20:14, 1 August 2006 (UTC)
The media are calling for mass vandalism on Wikipedia? Are they getting scared? Afraid of the competition? (in which case they should have picked Wikinews, but let's not give them any ideas). Maybe we need an article on information terrorism. DirkvdM 08:00, 2 August 2006 (UTC)
I wanted to check if this was added to the Colbert Report article, and it was, but that was deleted (http://en.wikipedia.org/w/index.php?title=The_Colbert_Report&diff=67155774&oldid=67149563) and now that page is protected for reasons of recent vandalism. Doesn't this page deserve to be vandalised? (just kidding) DirkvdM 08:10, 2 August 2006 (UTC)
Well, Colbert -- or at least his character on TV -- is a great believer in the democratic relativity of truth. He thinks that if something is repeated enough, it becomes true, and that Wikipedia is an ideal tool for exploiting this phenomenon. Of course, this is just the show's way of lampooning conservative American thinking. On the "The Word" segment, while he was talking about Wikipedia, at one point the caption read "The future will not be verified"; I take this as evidence that he's actually aware of WP:V in real life. Melchoir 18:25, 2 August 2006 (UTC)
Only seven edits? I thought Stephen Colbert's viewer figures were better than that. :-) DJ Clayworth 18:04, 2 August 2006 (UTC)

[edit] How to invest in different stock exchanges?

Can I use an online brokerage to invest in any stock exchange? I'm thinking specifically of the Toronto Stock Exchange (I am an American). How to specify the symbols used on each, since a three-letter symbol in one exchange might stand for a different company in another?

Thanks.

[edit] Corn earlage

What is corn earlage, and what is the difference between corn earlage and silage? --AR

Silage is a functional definition for something you feed to animals while stover is just described as everything but the grain. As for earlage...

[edit] Solubility vs. Temperature Curves for Glycine-Sodium Sulfate Solutions

How do I find Solubility vs. Temperature Curves for different concentrations of Glycine and Sodium Sulfate Solutions? Glycine is the simplest amino acid (NH2CH2COOH) and Sodium Sulfate is an inorganic salt, often called saltcake (Na2SO4). Thanks for your help. M.D.S.—

start with the CRC Handbook of Chemistry and Physics Xcomradex 08:22, 2 August 2006 (UTC)

[edit] Why gender body size difference in humans?

I'd like to make clear from the start that I have a lot of respect for women, that I'm a very gentle person, and that I abhor violence or aggression. To continue -

The average size of human males is greater than that of human females. I am not sure to what extent that this is true of other primate or mammalian species.

Some time ago I heard on the radio someone saying that this size difference evolved due to males fighting among themselves for female mates. I think the speaker was taking care to be P.C., as wouldnt it be more likely to be due to larger males raping less powerful smaller females, and thus evolution would select for both larger males and smaller females?

And, on a more minor point, perhaps human IQ evolved because of the machiavellian tactics required to get a mate and avoid deadly violence in a primitive society that was brutish and violent and without any ideas of gentlemanly behaviour?

You might be interested in our article on Sexual dimorphism. --Allen 21:11, 1 August 2006 (UTC)
Humans are social animals, meaning not that they (necessarily) behave more socially, but that they live in groups. Any aggression within the group would make it less stable and more vulnerable, giving offspring a smaller chance of surviving. Humans also form couples. A female without a mate might get less meat, which would stint the child's growth and such, giving it an evolutionary disadvantage.
However, if, like you do, you view humans as individuals fending for themselves, bigger and stronger women would have a better chance of protecting themselves and their offspring, both against rapists and other threats. I'd say that the fact that females are smaller supports the notion that they are social animals. Is this true for other animals as well? DirkvdM 08:21, 2 August 2006 (UTC)

Males are larger because they compete with other males. Peter Grey 00:56, 5 August 2006 (UTC)

People tend to leave out the possibility that we may have been created. Intelegent design may help you to understand not only our physical atributes but also our social structure.ĆÁĎ
Designs in nature don't show much intelligence, only brute-force trial and error. Peter Grey 19:20, 7 August 2006 (UTC)

[edit] Cashew

Is a cashew a legume or a nut?

Neither; it's a drupe. See Cashew for more. --Allen 21:16, 1 August 2006 (UTC)
Hey, who are you calling a drupe? Ca'shew see the notice about no personal attacks? ;-) --Fastfission 04:32, 2 August 2006 (UTC)
Quite a few cashew questions recently. How long until they have overtaken gulls? DirkvdM 08:24, 2 August 2006 (UTC)
Only a very slow gull could be overtaken by a cashew. Gandalf61 13:27, 2 August 2006 (UTC)
That would depend on who is throwing the cashew... - 87.209.70.231 20:39, 6 August 2006 (UTC)
He can if he's masturbating. – ClockworkSoul 22:04, 2 August 2006 (UTC)
XD --Proficient 20:41, 5 August 2006 (UTC)