Wikipedia:Reference desk/Archives/Science/2007 September 19

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September 19

Is this what it appears to be?

Just seen this video. Is this actually a gull seeing a female mallard being attacked (raped?) and deciding to intervene and save her? Hmmm. Opinions? --Kurt Shaped Box 00:17, 19 September 2007 (UTC)

Rape is a form of assault where one individual forces another to have sexual intercourse against that person’s will. I don't think rape really applies outside of humans. Lanfear's Bane 09:31, 19 September 2007 (UTC)

An interesting little scenario. The little I know about gulls leads me to believe that their goals in life are driven by food, territory, food, sex and food. (depending on the time of year) The setting here is some sort of pond or lake where the birds are obviously habituated to human presence and thus probably are used to human food handouts. I think the gull is more interested in the possibility of free food which she/he thinks might be available within the scrabble of bodies. Even the Canada goose has a gander. (ooh, pardon my pun!) I have noticed in places like this where there are largish numbers of birds all looking for a bit of free fodder, whenever there is a bit of a kerfuffle or argy-bargy between a couple of birds all the others tend to gravitate to that point as they maybe associate it with the frantic activity involved in filling your gizzard before anyone else and thus the presence of food.

It also crossed my mind that the gull may have been looking to take the opportunity to finish the stricken duck off itself and dine on some fresh meat. I've seen gulls mercilessly (mercifully? I don't think that the gull really cares either way) dispatching injured pigeons on several occasions. --Kurt Shaped Box 12:48, 19 September 2007 (UTC)

With regard to the the above comment about rape only being a human concept, mallard rape has been referred to for many years and is characterised by the absence of precopulatory behaviour normally seen in these birds and by the additional perceived reluctance of the female to engage in copulation evidenced by her attempts to escape. What is more interesting is that this behaviour often stimulates other nearby males who attempt to join in. Look at this http://elibrary.unm.edu/sora/Wilson/v092n03/p0409-p0409.pdf for further information.Richard Avery 10:17, 19 September 2007 (UTC)

Still, as this does not involve humans it cannot be categorised as rape. Neglect to perform a mating ritual before copulation does not constitute rape. As for other male mallards joining in to classify this as mallard gang rape is bordering on ridiculous. Sounds like we are straying into the realms of anthropomorphism on this topic. Lanfear's Bane 10:32, 19 September 2007 (UTC)

Assumming an animal has the cognitive skills to form an intent to have sex (or not), then in my opinion, rape can exist in that species. Obviously most animals can't tell us their intent, but we can make an educated guess based on behavior, and some animals (e.g. primates, some birds, and dolphins) have mastered enough basic language skills to directly communicate simple desires. 76.231.189.193 17:33, 19 September 2007 (UTC)

Language isn't really required. If the female sticks her rear end up and waits, she's giving consent. If she runs away, she's not. Pretty simple. StuRat 05:49, 20 September 2007 (UTC)

I remember reading about the mallard rape. It did raise a lot of questions as to whether "rape" can occur outside of Homo sapiens. I guess it comes down to whether murder, theft, incest or other human crimes also count. You can find equivalents in nature of many human crimes. This really isn't a Science question but rather Ethics. -- JSBillings 11:49, 19 September 2007 (UTC)

I wish that I hadn't mentioned the 'r-word' now. I didn't mean to start another one of these circular debates... :( --Kurt Shaped Box 12:39, 19 September 2007 (UTC)

My take on the use of 'rape' is that in this context it is an ornithological term to describe a specific pattern of behaviour which appears analogous to the human activity of this name. My sympathies KSB, like Forrest Gump said "Life is ..... Richard Avery 18:15, 19 September 2007 (UTC)

If you, as a human had seen that happening in front of you, you'd have tried to stop it, wouldn't you? Because preventing cruelty and suffering would be the right thing to do if it was within your power to prevent it. Are we that arrogant as a species that we really do believe that we are the only ones with views on what is acceptable and unacceptable? —Preceding unsigned comment added by 84.71.180.141 (talk) 19:39, 19 September 2007 (UTC)

Well I will be very interested when this case hits the duck courts to hear the outcome. How do you punish a duck anyway? Are duck judges severe? As for animals 'desiring' and 'consenting' these are again human emotions and actions. They do not exist outside in the animal kingdom. It's not a case of being so arrogant that humans believe their views are the only acceptable ones - it is however a form of arrogance to project human qualities onto animals and label their actions or instincts with human terms and equivilents. It also doesn't come down to ethics, again, these are human traits. Rape does not exist outside of humans. Or, if I am wrong, feel free to bring one of these thinking, talking, feeling, desiring ducks to me to explain duck law in regard to rape and then I will retract all of my recent comments. Lanfear's Bane 09:33, 20 September 2007 (UTC)

So the only way you'd accept that any animal has thoughts, feelings, desires or agency independent of some kind of mechanistic "instinct" is if it could articulate these qualities to you in English? Hmmmm, talk about arrogant. Maybe you could learn sign-language and find a signing chimp to communicate with, meet 'em halfway... 38.112.225.84 15:02, 20 September 2007 (UTC)

Oh that's right, I forgot that chimps could speak sign-language. I am always wondering what they are talking about on those nature documentaries or in the zoo. Lanfear's Bane 08:48, 25 September 2007 (UTC)

You know, my gerbil ate its babies because a child touched them. Should I take her to court? Seriously, humans and animals are different, especially when it comes to ethics. The way this argument is heading, one could conclude that animals shouldn't be predators anymore. :D --JDitto 01:43, 26 September 2007 (UTC)

Chemical Nomenclature

When considering the hydrogen in a bond, is it treated like a non-metal or a metal? For example, with the compound HF, would it be called "Hydrogen fluoride" (ionic conjugation) or "Hydrogen monofluoride" (covalent conjugation)? Thanks. Acceptable 01:57, 19 September 2007 (UTC)

Hydrogen is named as a metal in compounds with a more electronegative element (for example hydrogen fluoride) and as a non-metal in compounds with a less electronegative element (for example sodium hydride). —Keenan Pepper 02:24, 19 September 2007 (UTC)

Quantum physicist's name?

Someone suggested that I should look into the work of a certain quantum physicist, but now I can't recall the scientist's name. All I can remember is that it sounded something like Muset or Mussay, but I'm not sure. I looked on the list of physicists and no one there sounds like the right one. I know it isn't Harrie Massey or Amédée Mouchez — I was told this man was a contemporary of Star Trek creator Gene Roddenberry. (I hope I'm not waaaaay off on the name, but it's possible!) Thank you kindly. — Michael J 02:25, 19 September 2007 (UTC)

Could maybe be Albert Messiah (last name pronounced roughly mess-ee-yah, not messEYEah)? He wrote a standard graduate or advanced-undergrad text on QM, I think. --Trovatore 02:31, 19 September 2007 (UTC)

Maybe it could be a first-name, Murray Gell-Mann? --Taktser 04:25, 19 September 2007 (UTC)

Archaea or Bacteria, which came first?

Greetings! I finished reading the articles archaea and bacteria, but I still have a doubt as to which domain appeared first on our planet? From what I can gather, the species of the domain archaea tend to be hyperthermophiles living near geysers, that Earth during the Archean eon was much warmer than today, that species adapted to survive at lower temperatures evolved later than the hyperthermophiles, and that the species of the domain bacteria can adapt to a much wider range of temperature environments. Would this mean that archaeon appeared before bacterium? In the article archaea it also states that the archaea are more closely related to the more advanced eukaryotes, would that mean it was bacteria first followed by archaea? Thanks in advance! --Taktser 04:07, 19 September 2007 (UTC)

I think there is no conclusive evidence for one or the other. Studying different genes suggest a lot of gene swapping occured and there is no simple tree structure of organisms. There are more than just extreme thermophiles! Graeme Bartlett 12:30, 19 September 2007 (UTC)

As far as I'm aware, archaea are usually believed to be more closely related to eukaryotes then bacteria. I.E. bacteria diverged first. However I don't know whether there is really an answer to which appeared first. It's a bit like asking which appeared first humans or chimpanzees (or orangutans or something)? The answer is neither since both are modern species. It will depend on your definition of what's a human and what's a chimpanzee. Nil Einne 20:11, 19 September 2007 (UTC)

You know, they could have at the same time too. --JDitto 01:46, 26 September 2007 (UTC)

What is the long term result of electrolysis of water?

During electolysis of water stand alone hydrogen and oxygen gas are split from the water compound. My question is what happens to these gases after this? Can they ever get together again? Or is the process which occurs everywhere lead acid batteries are used, especially in motor vehicles, reducing the global supply of water and accelerating droughts and climate change generally?Vorc 04:57, 19 September 2007 (UTC)

From Hydrogen: "In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by identifying the gas from a metal-acid reaction as "inflammable air" and further finding that the gas produces water when burned."

Another word for burning is combustion:

"A simpler example can be seen in the combustion of hydrogen and oxygen, which is a commonly used reaction in rocket engines:

2H
₂ + O
₂ → 2H
₂O + heat

The result is simply water vapor."

See also Fuel cell, in which hydrogen can be oxidized to produce electricity and water.

(ec)They can get together again. Actually, if you put hydrogen gas and oxygen gas together at room temperature, they will spontaneously reform water. This is a slow process however, unless you provide some spark for the reaction to speed up, in which case you might get something like The Hindenburg. Someguy1221 05:07, 19 September 2007 (UTC)

This was one of my science teachers favourite tricks. As far as I recall, we mixed oxygen and hydrogen in a tin can, pressed the lid on, and somehow ignited it. There was a bang, the lid flew off, and inside the can were a few drops of water.--Shantavira|^{feed me} 07:23, 19 September 2007 (UTC)

Please be careful or people might copy your bad memory... The Hindenburg was lots of nitrogen from the atmosphere to slow things down. If you mix pure hydrogen and oxygen together in a tin you have got a potential gas detonation on your hands which is potentially seriously dangerous (to your hearing in particular)>> some people do it in a balloon but I still wouldn't recommend it. The tin can trick is normally to fill the can with hydrogen (or methane) and light the gas diffusing out of a small hole: you get a brief flame because the mixture in the can is too rich to burn but then enough air gets into the can to mean the flame goes back into the can. Heat generated increases pressure and unless the tin lid can keep about 8 bar in (no, it cannot) you get a loud pop. Any, not the pure gases (the oxygen comes with the rest of air). --BozMo talk 11:42, 19 September 2007 (UTC)

The Hindenburg wasn't helped by the flammable chemicals that they used to paint the thing - if the problem had only been the hydrogen, it would have been a much smaller problem. Hydrogen (being very light) would have carried the fire upwards and away from the passengers and crew - and that would have prevented all of the gas-filled cells from burning, allowing the craft to drift more slowly towards the ground. The flames you see in that infamous newsreel are far too luminous to be hydrogen flames - what you are seeing is the envelope burning. Indeed only about a third of the people on board died - most of those because they jumped from the gondola - the remainder being crew members up at the nose of the craft. Every person who stayed on board inside the gondola, survived. It's unfortunate that this was such a notorious event because a properly designed hydrogen-based Zepplin is a perfectly reasonable aircraft that would be vastly cheaper to run than modern helium-based craft. With modern materials for the gas bags - proper monitoring of oxygen levels inside those bag - construction techniques to isolate a disaster in one gas bag from destroying the others in a chain-reaction - and control of arcing due to static buildup, there is no reason why we couldn't still fly craft like the Hindenburg with at least the degree of safety that we fly jumbo jets. SteveBaker 14:15, 19 September 2007 (UTC)

I disagree. The main safety risk of blimps, dirigibles, zeppelins, and hot air balloons (or any other lighter-than-air craft) is that they can't be controlled in strong winds, which are common and not always predictable. The risk from containing an explosive gas is secondary to this risk. (I do agree that hydrogen-filled craft are not as dangerous as they appear, however.) StuRat 03:23, 20 September 2007 (UTC)

I agree that wind is a major issue when these gizmos are close to the ground - but they have so many advantages in some applications that this problem can be worth circumventing. Forget about carrying passengers - think about freight. Ships are an efficient way to carry goods around the world - but you run into trouble when there are no convenient oceans nearby. Replace a ship with a truly gargantuan airship and suddenly that restriction has gone away. The dramatically smaller drag factor in moving through air rather than water should make airships cheaper to operate and a lot quicker too. But yes - landing and taking off again is a tricky thing (but then so is docking a ship in a heavy current). Lowering cables to the ground and winching the thing down seems like the smart solution. There are also applications for airships in replacing communications satellites and terrestrial radio antennae. The relative cheapness of Hydrogen compared to Helium - and the vastly improved lift capability per unit volume is what is needed to make these things economically feasible - but the "Hindenburg factor" means that nobody wants to invest money in them...which is a shame because the problems that caused the demise of the Hindenburg are easily overcome. Also, only about 36 people and two dogs died in the accident - two thirds of the passengers and crew survived - compared to the 89 that died (just 30 survived) in an MD-80 airliner as it attempted to land in Bangkok a couple of days ago. I guarantee that the Hindenburg disaster will be remembered around the world 100 years from now - but One-Two-GO Airlines Flight 269 will largely be forgotten in...well, come to think about it, I think it's pretty much already been forgotten everywhere outside Thailand. SteveBaker 14:03, 20 September 2007 (UTC)

When you electrolyse water with direct current electricity, you get oxygen coming off of one of the electrodes and hydrogen coming off of the other. This enables one to capture the hydrogen safely without oxygen mixed into it - and if you do that, there is no immediate danger of the gas exploding. SteveBaker 14:15, 19 September 2007 (UTC)

Most of the hydrogen and oxygen will eventually become water again. However, some of the hydrogen may rise to the upper atmosphere and be blown away from the Earth by the solar wind. Of course, nobody would be able to convert enough water to hydrogen and oxygen for this to have any noticeable effect. However, if they could, we would eventually have more oxygen in the air and less water in the oceans, yes. StuRat 03:33, 20 September 2007 (UTC)

It is important to note that there is a very large activation energy for the combination of H2 and O2. Without an ignition source the reaction is very slow —Preceding unsigned comment added by Shniken1 (talk • contribs)

Wouldn't lightning provide the needed activation energy ? StuRat 04:33, 21 September 2007 (UTC)

With deep-cycle lead-acid batteries you can use caps with a catalyst (platinum?) that reforms the gases into water, so that the batteries need less water added later.Polypipe Wrangler 15:08, 20 September 2007 (UTC)

Methanol and Ethanol

If ethanol is used to treat methanol poisoning, is it possible to mix the two at a ratio so that it's no longer toxic (as in methanol toxic)? --antilived^{T | C | G} 05:15, 19 September 2007 (UTC)

Get it into your thick head. Ethanol is poison. Methanol is poison. A mixture of ethanol and methanol is poison. Ever wonder what happens to young people when they drink a lot of alcohol? That's right, they get alcohol poisoning. So whether you drink ethanol or you drink methanol, you are putting poison into your body. The idea that you can mix ethanol with methanol and come up with a solution which is "no longer toxic" is utter rubbish. 210.49.155.132 13:20, 19 September 2007 (UTC)

Yes - agreed. Methanol is horribly toxic - it causes blindness in even quite small doses. Ethanol is less toxic - but it's still nasty stuff in high concentration. If you have life-threatening methanol poisoning then ethanol (being the lesser of two evils) might save your life (but probably not your eyesight)...but the idea that these two poisons somehow cancel out is ludicrous. SteveBaker 13:55, 19 September 2007 (UTC)

I think the question antilived was trying to ask was whether you could create a mixture of the two so that the methanol poisoning would be "treated" by the ethanol consumed with it. From what I can understand from this website [1] Methanol is toxic because it is broken down by the enzyme alcohol dehydrogenase in the liver to form formic acid and formaldehyde. Ethanol in large quantities is administered to a methanol poisoned patient because it will compete for the enzyme with the methanol. This slows down the metabolism of methanol allowing doctors to haemodialysis it away or clear the body through the kidneys (which occurs much slower than being broken down in the liver). Just drinking a mixture of ethanol and methanol is not enough because some of the methanol will still be metabolized in the liver, just over a longer period of time, meaning you are still going to be poisoned. You could try to design the solution so that the amount of methanol metabolized would be minimal and would avoid side affects, but since everyone's body chemistry and alcohol metabolizing ability are different it would be difficult to predict the severity of the poisoning. **DISCLAIMER:** I am not an expert, and trying this would be REALLY REALLY REALLY dumb. Sifaka ^talk 15:27, 19 September 2007 (UTC)

Actually the idea that these two cancel each other out is about the easiest explanation you could give to someone who doesn't understand how methanol poisoning works. Methanol in and of itself doesn't cause the toxic effects. The effects come from byproducts of the breakdown of ethanol in the liver (by the enzyme alcohol dehydrogenase). These cause initially blindness, but it is not necessarily permanent. If treated with ethanol, the ethanol competes with the active site of the enzyme and is broken down into harmless by products. You could probably handle an intake of ~100 times more ethanol than methanol depending on how much methanol you have in you system (which would at least reduce the break down of methanol by a factor of 10^2). This does not take into account the fact that alcohol dehydrogenase has much more affinity for ethanol than methanol. So you can essentially stop the breakdown of methanol into toxic molecules by drinking/injecting enough ethanol. Then methanol is removed only by the kidneys (like 10000:1 Kidneys:Liver) and viola no lasting effects if caught early. If someone had a serious case of methanol poisoning, you really wouldn't be worried about their sight anyway. You would be more worried about keeping formic acid and formaldehyde out of their blood and lungs.
Now I'm certainly not suggesting that it is as simple as getting drunk. You need to go to the hospital so your vital signs can be monitored. CNS depression from both alcohols can cause bradycardia and hypoxia, but this would be easily compensated for in a hospital setting.
And if at this point your still thinking, "But ethanol is toxic too!?" Well, in terms of toxicity, methanol is an F5 tornado and ethanol is a dust devil. The risks of this treatment are essentially negligible in comparison to the almost certain death of someone with a serious case of acute methanol poisoning.
There was apparently an editing conflict.
Mrdeath5493 15:29, 19 September 2007 (UTC)

Ethanol is not some sort of cure that neutralizes all effects of methanol rendering it harmless - you're thinking like it's some sort of acid base reaction, it's not.87.102.116.240 16:36, 19 September 2007 (UTC)

Why are there suddenly so many questions about ethanol being used to treat methanol? — Daniel 22:24, 19 September 2007 (UTC)

You read stuff here and it makes you think of other, related stuff to ask that you never, ever thought that you wanted to know before? --Kurt Shaped Box 22:58, 19 September 2007 (UTC)

Perhaps they are writing a fiction book and need a "home cure" for methanol poisoning ? StuRat 04:56, 20 September 2007 (UTC)

I thought my explanation was pretty clear, but obviously I'm talking over your heads. It is true that ethanol doesn't immediately neutralize methanol's toxic properties, but you really wouldn't know the difference by observing someone being treated with ethanol for methanol poisoning. It will make them better, almost immediately. Even if there was permanent damage, proper treatment will pretty much completely reverse the course of the pathology within 36 hours. There is only one other option for treating methanol poisoning and it is Fomepizole. I live in Arkansas and know for a fact that there are regional ER's that protocol ethanol as a remedy. Sorry to everyone out there that thinks they know what they are talking about, but this treatment works, very well.
Mrdeath5493 05:51, 20 September 2007 (UTC)

But that wasn't the question. What was asked was whether you could mix them from the start in such a way that the methanol wouldn't poison you. The treatment you're talking about requires administration of ethanol on an ongoing basis, until the methanol is out of the system; it's not good enough, I think, to give one dose up front.

All the more so if, as you said, "alcohol dehydrogenase has much more affinity for ethanol than methanol". Because that means the ethanol will get used up, and the body will make more alcohol dehydrogenase, and now the methanol is still around to be turned into formaldehyde (kidneys haven't had time to get rid of it), and the ethanol isn't there to prevent it anymore. --Trovatore 21:07, 20 September 2007 (UTC)

Trovatore, other than being completely wrong in your assumptions you are right. Notice the words "proper treatment" above. One dose probably wouldn't do it. The obvious solution is to add more ethanol (if what was there is gone). Normal saline + diuretic rings a bell too (increased action of kidneys). Also, dialysis can be used. I'm pretty sure that any competent Physician understands the basic concepts of biochemistry anyway.
Mrdeath5493 21:41, 20 September 2007 (UTC)

I don't believe you carefully read the original question. --Trovatore 21:46, 20 September 2007 (UTC)

Well, I don't think you read the Science help desk every day. There have been 2 other similar threads to this one and if read chronologically, you obviously see that most of the users that usually answer questions on the desk don't think ethanol is a good treatment. So, I decided to do some extra homework. Here is a Quote from Current Medical Diagnosis & Treatment. 2007. Stephen J. McPhee et al.

Treatment [for methanol poisoning]

Emergency and Supportive Measures

For patients presenting within 30–60 minutes after ingestion, empty the stomach by gastric lavage (see Antidotes & Other Treatment-Gastric Lavage). Charcoal is not very effective but should be administered if other poisons or drugs have also been ingested.

Specific Treatment

Patients with significant toxicity (manifested by severe metabolic acidosis, altered mental status, and markedly elevated osmolar gap) should undergo hemodialysis as soon as possible to remove the parent compound and the toxic metabolites. Treatment with folic acid, thiamine, and pyridoxine may enhance the breakdown of toxic metabolites.

Ethanol blocks metabolism of the parent compounds by competing for the enzyme alcohol dehydrogenase. The desired serum ethanol concentration is 100 mg/dL. To achieve this, administer a loading dose of approximately 750 mg/kg orally or in a dilute intravenous solution (available from the pharmacy in 5% and 10% solution), and then provide a maintenance infusion of 100–150 mg/kg/h. The infusion will have to be increased to about 175–250 mg/kg/h during hemodialysis to replace dialysis elimination of ethanol.

Fomepizole (4-methylpyrazole; Antizol), blocks alcohol dehydrogenase and can be used instead of ethanol. A regional poison control center (800-222-1222) should be contacted for indications and dosing.

My regional poison control office just happens to be on the same floor as the college of pharmacy I attend. They said they recommend ethanol...Imagine that.
Mrdeath5493 22:03, 20 September 2007 (UTC)

If you read the threads carefully you'll see that few posters have said otherwise. There was one anon who said "ethanol DOES NOT treat methanol poisoning" but then immediately contradicted himself. Everyone else has argued against other aspects, such as injecting a non-medical-grade spirit or trying to make methanol "safe" by including enough ethanol with it. --Trovatore 22:46, 20 September 2007 (UTC)

So I should probably just pretend that you didn't offer an opinion directly contradictory to mine 5 posts up? All that stuff about ethanol leaving the system and methanol breaking down faster... If you hadn't, of course, I would not have pushed my point. On top of the doubts you raised earlier concerning my position, I was referring to this specific comment
"Ethanol is not some sort of cure..."
You are correct in your analysis of the previous posts; almost no one contradicts me there. It does seem, however, that the people who initially said something to the effect of "Treating methanol poisoning with ethanol is stupid..." have retroactively erased their initial statements or just edited them. So, I guess I am preaching to the choir even now.
Mrdeath5493 01:05, 21 September 2007 (UTC)

You shouldn't pretend anything. I never said ethanol was not a treatment for methanol poisoning. I said you couldn't drink a mixture of ethanol and methanol and expect the ethanol to protect you. If you read my comments otherwise, you read them wrong. --Trovatore 01:15, 21 September 2007 (UTC)

So this:
"the ethanol will get used up, and the body will make more alcohol dehydrogenase, and now the methanol is still around to be turned into formaldehyde (kidneys haven't had time to get rid of it), and the ethanol isn't there to prevent it anymore."
was in reference to a mixture of eth/meth in a glass and not about treating methanol poisoning?
My bad.
Mrdeath5493 01:34, 21 September 2007 (UTC)

Purpose of review articles from writer's perspective

Apparently scientists not working for a corporation have to publish in order to recieve grants. Does the publishing of review articles count towards this? If not, why do people write them? --Seans Potato Business 15:25, 19 September 2007 (UTC)

Publishing a review (depending on what it is) can count towards 'recognition' but won't really help to get grants (which need evidence pf original research usually).

However like all published written work payment is usually included.

Plus maybe they just like writing reviews - I'd do that for nothing on a topic that interested me.87.102.116.240 17:07, 19 September 2007 (UTC)

Surprising though it may seem, scientists actually do science - they don't just seek grant money. Publications are there to move science along - not just to get grant money. If publishing a review will help people to get closer to whatever it is they are working on - then writing one is a valuable use of a scientists time. Grants are a means to an end - they aren't the goal of science! (Although sometimes it seems like that). SteveBaker 17:53, 19 September 2007 (UTC)

"However like all published written work payment is usually included." Really? I've never paid nor gotten paid for journal articles. Maybe in some fields or some journals, but certainly the minority in the sciences I know. DMacks 18:20, 19 September 2007 (UTC)

I meant book reviews rather than literature reviews in journals.87.102.116.240 18:29, 19 September 2007 (UTC)

Further to DMacks, the authors often pay a "per page charge" to have articles published or to have colour figures. -- Flyguy649 ^talk _contribs 18:27, 19 September 2007 (UTC)

Note that when they do pay, it will usually be mentioned at the end of the article Nil Einne 20:03, 19 September 2007 (UTC)

When it comes to writing review articles, remember that this requires them to familiarise themselves with the literature and the work they're reviewing. While most scientists writing reviews AFAIK usually work in that specific area already so would already be fairly familiar with the literature, I suspect they would still learn something out of the process. Remember one of the best ways to test how well you understand something is to try and teach it. It may also be an opportunity for them to consider things to teach at university. Writing reviews aren't the only things they do for 'free'. Peer reviewing journal articles is also something most experienced scientists will do but they aren't paid for it. It's considered part of being a scientist. This is actually covered fairly well in Peer review Nil Einne 20:03, 19 September 2007 (UTC)

From a more political (and perhaps cynical) perspective, scientists will often have different hypotheses about scientific fields. Similar data can be interepreted in different ways and an experienced scientist may have a number of papers published in a field that supports one hypothesis, while another scientist may have a body of work that supports a conflicting interpretation. Review articles can help "sway" the scientific consensus towards one of these interpretations. Its no co-incidence that review articles will often contain many, many citations of the author's own original research papers. In a recent review (PMID 15985310) I read, 42 of the 113 citations were by the authors of the review. This has the added bonus of boosting the the impact factor of the journals the authors have published in, and the authors' own H-indices. Rockpocket 21:31, 19 September 2007 (UTC)

Regarding specifically whether you get "credit" for review articles: In my institution, which is a government lab, we have specific minimum requirements for number of original research papers per year. For us, review articles don't count towards this. ike9898 17:25, 20 September 2007 (UTC)

Developmental term I have forgotten

In some organisms, the presence and subsequent contact with of a large number of peers triggers a developmental change causing the individual to become larger than its peers and engage in cannibalistic behavior. I forget what it is called. Any ideas? Sifaka ^talk 15:32, 19 September 2007 (UTC)

Can you suggest one or two species that do this? It might make the search a little easier. SteveBaker 17:48, 19 September 2007 (UTC)

Sorry, I can't remember any in particular, although I think some examples were fish or lizard-shaped amphibians. I read about it so long ago... Sifaka ^talk 18:32, 19 September 2007 (UTC)

GOT IT!!! Cannibalistic Polyphenism It's now a redirect to polyphenism for now... Sifaka ^talk 19:14, 19 September 2007 (UTC)

I changed it to a redirect to the Cannibalistic Polyphenism section of polyphenism. — Daniel 22:17, 19 September 2007 (UTC)

Basic Axioms of Physics

I read somewhere that you could write the basic axioms of physics, which would describe much of the universe around us, on a single index card. I assume that by axioms, the meant the fundamental underlying assumptions. So, 1. Is this true? and 2. What would these axioms be? Czmtzc 20:29, 19 September 2007 (UTC)

I wouldn't really use the term 'axiom' with 'physics'. The axioms of arithmetic or euclidian geometry could certainly be expressed in so little space - but physics is about measurement and experiment. The idea of something being so self-evident that you don't need to prove it is kinda alien to that concept. Perhaps you don't mean 'axiom'...the basic equations of physics are certainly fairly compact - and indeed some physicists suggest that we can finally boil a 'theory of everything' down to an equation that you might fit in so little space - but that's the opposite of an axiom.

As an example, here are the axioms around which all of Euclidean geometry is based:

1. Any two points can be joined by a straight line.
2. Any straight line segment can be extended indefinitely in a straight line.
3. Given any straight line segment, a circle can be drawn having the segment as radius and one endpoint as center.
4. All right angles are congruent.
5. Parallel postulate. If two lines intersect a third in such a way that the sum of the inner angles on one side is less than two right angles, then the two lines inevitably must intersect each other on that side if extended far enough.

SteveBaker 20:52, 19 September 2007 (UTC)

• This might be relevant: Hilbert's sixth problem. --JWSchmidt 21:02, 19 September 2007 (UTC)

We do sometimes use "axiom" in physics to mean the fundamental equations that define a particular theory. For instance, you could say that the Schrodinger equation is an axiom of non-relativistic quantum mechanics. You don't prove it in a mathematical sense, you prove it by empirically confirming the predictions of quantum mechanics. I would choose the Einstein equation and the standard model lagrangian. You could write them both on an index card, if you have small handwriting for the standard model lagrangian! --Reuben 21:26, 19 September 2007 (UTC)

In so far that mathematical axioms are considered to be "true" they are empirically derived, just like physical axioms. They are also based on measurement; counting for example is clearly a measurement procedure. The predicitons of the "addition" axiom can be empirically tested by counting. Just count two heaps of apples, put them together, count again, and compare with the prediction by addition. You see - mathematics *is* physics. —Preceding unsigned comment added by 84.187.37.196 (talk) 22:21, 19 September 2007 (UTC)

I'm not sure a pure mathematician would agree with you. I think they would argue that arithmetic is a set of theorems that depend on the axioms and the axioms are just assumptions built into the thing at the beginning. If, as a result, addition appears to be applicable to the problem of counting things in the real world then all well and good - but the math doesn't depend on it. Notably, the axioms of Euclidean geometry that I posted earlier are not things that are necessarily true in the real world. Mathematicians have a lot of fun by denying one or other of the axioms - or negating one altogether and seeing what pops out. Denying Euclids parallel postulate results in all sorts of interesting non-Euclidean geometries that are interesting but do not necessarily represent 'real world' stuff. In fact, in normal 3-space in our universe, several of those postulates aren't true because of the bending of space-time due to gravity. That in no way invalidates any of Euclids theorems because they only apply in the event that you assume the axioms are true. SteveBaker 22:31, 19 September 2007 (UTC)

As a pure mathematician myself, I suggest the axioms of ZFC (especially replacement and choice) as an antidote to the idea that all mathematical axioms are closely derived from physics. While some would still argue that all mathematics is empirical in nature, most of it has to be extremely indirect. Algebraist 22:57, 19 September 2007 (UTC)

There is a fundamental difference of opinion among pure mathematicians on this point. Oversimplifying wildly, there are two basic schools, the "realists" (or "Platonists"), and the "formalists" (in which camp, just for now, I'm including fictionalists and people like George Lakoff). For a realist, mathematical objects are real (though non-physical) objects, and axioms are not arbitrary but are supposed to describe those things. For example ZFC should describe the von Neumann hierarchy (note that the von Neumann hierarchy is much more intuitively "natural" than ZFC itself). I lean to the realist school myself, and would argue that there is an empirical component to the discovery of axioms, particularly where it comes to things like large cardinals. --Trovatore 23:09, 19 September 2007 (UTC)

Hmmm - interesting! So do you assert that it is somehow wrong to pick a set of axioms that don't match reality and then attempt to prove theorems based on them? Is it perhaps merely so pointless that you don't think it's worth doing? Or are you just saying that the standard set of axioms around which most of mathematics is based is based upon 'reality'? SteveBaker 13:39, 20 September 2007 (UTC)

A little bit of 2, but mostly 3. Certainly there's nothing "wrong" with investigating the consequences of arbitrary axioms, and once in a while it even turns out to lead somewhere. But the importance of the axiomatic method as a whole is somewhat overestimated by most interested outsiders and even a lot of mathematicians. Most proofs are not really axiomatic per se. We tell ourselves that we could, if we had to, convert them into axiomatic proofs by routine methods, and this is probably true, but is almost never actually checked. --Trovatore 17:18, 20 September 2007 (UTC)

OK - I'll buy that. It's a pretty reasonable stance. But we know that not all theorems are provable - but we try to build new theorems on top of older ones that we 'know' were correctly derived from yet older ones - and somewhere at the bottom of the whole pile are a handful of axioms that we can't prove. The iffy part happens if you are pretty certain that some unproven theorem is true - and therefore rely upon it. This effectively introduces another axiom - but one that you hope can be removed at a later date. The only question is whether you argue that those axioms are some kind of self-evident 'truth' or whether you say "this huge pile of theorems is only true if you assume these axioms are true". My view is that the former is a bit limiting because it prevents you from doing things like denying Eulers parallel postulate (even though you generally believe it to be a self-evident truth) - and thereby figuring out non-Euclidean geometry - which would be a shame because it subsequently became very useful in other areas. On the other hand, denying that 1+1=2 might well generate a huge pile of interesting theorems - but if none of them apply to reality, what's the point? Both ways are relevent. SteveBaker 20:03, 20 September 2007 (UTC)

If you want to model a solar system (which can't be modeled accurately with quantum physics) down to the atom (which can't be modeled accurately with general relativity) you'd have to use a theory of everything. As far as I know, any of them can model the universe relatively accurately. No computer is powerful enough to run such a model, and I don't think it's even theoretically possible to make one that can, as it would be modeling itself, but that wasn't your question. — Daniel 02:57, 20 September 2007 (UTC)

It's not always necessary to model the entire universe - there is merit to using a theory-of-everything in order to model something simple. But it bothers most people to have to pick the set of fundamental laws (relativity or quantum theory) depending on the nature of the thing they are trying to figure out. There are cases (such as the Hawkings radiation from a black hole) that are simple enough to simulate in a computer and which require both sets of laws - and they don't agree. The consequences of picking the wrong set of theories in order to solve a particular problem is to get the wrong answer. So there is certainly merit in seeking the theory-of-everything - if only as a way to fix these corner-cases. SteveBaker 13:40, 20 September 2007 (UTC)

You can certainly write some axioms of some of the forms of physics on a card. But that wouldn't get you much. All of Special Relativity, for example, falls out of the following two axioms: 1. Galilean relativity holds for all frames of reference and all forces; 2. the speed of light is seen as constant from all frames of reference. Now that looks pretty simple but it took a lot of big brains (starting with Einstein, but others too) to figure out all of the implications of those two things and it takes a lot of explanation and extrapolation to show how inside those two, simple axioms are things like time dilation and length contraction. General Relativity can almost completely be summed up in the single axiom that gravitational acceleration can be described by the curvature of space and time, but knowing just that gets you almost nowhere in terms of actual physics or calculations.

It should be noted for historical purposes that both of the above are care of Einstein, and that Einstein was himself an explicitly axiomatic thinker, believing that if you started out with the correct axioms (and often a reexamination of simple concepts like "space" and "time" and "acceleration") then everything else would fall out. As an approach it worked very well for things like SR and GR but not well at all for things like quantum mechanics. --24.147.86.187 15:04, 20 September 2007 (UTC)

It sounds to me you may actually be asking for Hamilton's principle which arguably has the whole of physics in a single equation? --BozMo talk 16:30, 20 September 2007 (UTC)