Wikipedia:Reference desk/Archives/Science/2010 May 23

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May 23

Spider behaviour

In our shared house for university we have a dead spider that's been encased in some sort of plastic or wax near the ceiling for at least a year (before we moved in, damned if I'm gonna clean it!).

Today I've seen a big, similar sized spider climb up towards the dead spider about a day ago and it seems to be staying there up until this point of writing. It looks to be moving whilst up there too, and looks relatively healthy so I don't think it's dying.

That said, what would cause this sort of clinging behaviour to a dead, very-different-to-how-it-would-have-been-a-year-ago spider? Do spiders try to rescue their kind? Do they go off to die in similar places, or hang around with their dead counterparts? Is this just a coincidence and it might move in a couple of hours? Cheers!

Regards, --—Cyclonenim | Chat  02:32, 23 May 2010 (UTC)

You're presuming incorrectly that the source of the spider's attraction to that spot is the dead spider. Its attraction is to a good place to hang out; it would have no interest in the dead spider, but rather to that part of the ceiling itself. 63.17.50.130 (talk) 02:52, 23 May 2010 (UTC)

It certainly could move in a couple of hours, maybe to someplace you wouldn't like. If you want to dispose of it, try extending your vacuum cleaner's hose attachment, and the critter's last thought will be about how life sucks. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:57, 23 May 2010 (UTC)

Ha, yes maybe. Maybe it is a good place to hang out, but it's not even in a corner or somewhere remotely comfortable. It's just sitting on top of the dead spider. Regards, --—Cyclonenim | Chat  12:13, 23 May 2010 (UTC)

Would you rather live with a dead spider on your ceiling than to clean it? Dauto (talk) 03:31, 23 May 2010 (UTC)

Well it's never really been an issue, I guess it's hard to not sound disgusting unless you've actually seen where we're living. The place is an absolute shit hole as it is, a little dead, encased-in-wax spider from the previous occupiers isn't really going to bother me. Regards, --—Cyclonenim | Chat  12:13, 23 May 2010 (UTC)

How Spiders Work Count Iblis (talk) 16:42, 23 May 2010 (UTC)

Aircraft repairs, part 2

If the same saboteur as cut the generator wires also puts emery powder into the propeller pitch-change mechanism, could the damage be repaired by replacement/repair of parts and subsequent regreasing, or does it require replacing the whole screw? (Assume that the screw in question is a two-bladed Hamilton-Standard Hydromatic, if that helps.) 67.170.215.166 (talk) 03:07, 23 May 2010 (UTC)

• Hmmm, the wikipedia has a legal disclaimer, medical disclaimer, isn't it time for a "life critical systems disclaimer"? Right, I know that 67.170.215.166 wrote about a fictional setting, not real hardware, but what if one day someone takes wiki-advice on this matter seriously? East of Borschov (talk) 04:59, 23 May 2010 (UTC)

This kind of work is only done by licensed aircraft mechanics, and they know enough to always refer to the manual, not the Wiki reference desk. So there's no chance of this advice being taken seriously. 67.170.215.166 (talk) 05:57, 23 May 2010 (UTC)

Speaking of which, this being a reference desk, I suggest that you might consider referring to an aircraft mechanic. If you have trouble locating one, give me the identifier of your nearest local airport and I can see if I can help. Falconus^{p t c} 14:13, 23 May 2010 (UTC)

I believe this question refers to a fictional novel the OP is writing in which a pilot needs to make some emergency repairs to his plane (in a rainstorm, if I remember correctly), as the second part of a question he posed on the Ref Desk a few days ago. Hence, "Part 2." OP, you might give us a quick recap so we're all on the same page here. AlexHOUSE (talk) 21:57, 24 May 2010 (UTC)

Well, the story is, the pilot and crew are making a flight around the world (which is a scientific mission to study climate change as well as a commemorative flight for Amelia Earhart), and they're forced down in Pakistan due to engine problems, and while getting the spare parts they get in trouble with the local mutaween for breaking sharia law and decide that they have to escape to India; but one of the mechanics happens to be racist against Americans (which is very common in Pakistan, by the way) so he sabotages the plane by cutting the generator wires and reattaching them in such a way that they would vibrate loose in flight (so that the pilot wouldn't notice until well under way) and also loosens one of the engine exhaust valves to make it drop into the cylinder and wreck the engine. Well, after reading a recent posting by Alex Mandel on the Amelia Earhart talk page, I got an idea to have the said anti-American mechanic also throw some emery powder into the propeller pitch change mechanism in the hope that the prop would get stuck in the wrong pitch and hopefully make the plane crash on takeoff. My idea is that he does that, but the crew catch the malfunction in time and fix the propeller; but this will be contingent on how long it will take (the flight can't be delayed too long because of the monsoon season arriving). So if the damage can be fixed by simply re-grinding the damaged parts and/or replacing them with brand-new parts and then regreasing the mechanism, then I'll go ahead and put it in the novel; but if it requires replacing the whole prop, then I'll have to skip it because it will take too long to repair. So what's your take on this? 67.170.215.166 (talk) 06:09, 25 May 2010 (UTC)

No experience with pitch-change mechanisms in particular, but I wouldn't expect emery powder (or sand, or any other abrasive) to be fast-acting enough to cause problems on the flight. Six months down the road is another matter entirely. --Carnildo (talk) 00:00, 26 May 2010 (UTC)

Stable ranges for Albedo and Emissivity of Earth

The Earth has a Global Annual Average Temperature of 14°C.
The Global Average Albedo is 0.30 and the concomitant Emissivity is 0.622.
Hence:
$T_{p}={\frac {((6.955\times 10^{8})^{2})\times (5778^{4})\times (1-0.3)}{(4\times 0.622\times 149597876600)^{2}}}={14}$
(derived from Luminosity)

So I was wondering how far that 14°C can shift and the planet still sustain some "liquid water,"
somewhere on the planet, what range is possible, and also what is range for the Albedo,
and the range for the Emissivity, for a stable habitable temperature for Earth life?
For clarity, this question is only about the Earth, as a reference point, not exo-moons.
Earth's temperature range is 60°C to -90°C, or 150 degrees.
There must be limits.
Global Annual Average Temperature Maximum: ??
Global Annual Average Temperature Minimum: ??
Minimum Albedo: ??
Minimum Emissivity: ??
Maximum Albedo: ??
Maximum Emissivity: ??
24.78.178.147 (talk) 01:30, 23 May 2010 (UTC)

I won't answer your question, but I will fix your equation.

$(T_{p}+273.15)^{4}={\frac {((6.955\times 10^{8})^{2})\times (5778^{4})\times (1-0.3)}{4\times 0.622\times (149597876600)^{2}}}=(13.78+273.15)^{4}$

T_p=13.78°C Dauto (talk) 05:48, 23 May 2010 (UTC)

Thanks, I missed that because I'm used to Excel not the code here.
((((((695500000)^2)*(5778^4)*(1-A)/(4*ε*(149597870690^2)))^0.25)-273.15) = 14.000
A=0.3
ε=0.62009
24.78.178.147 (talk) 04:42, 24 May 2010 (UTC)

Pineal gland

Is serotonin produced in the pineal gland? At present our article on this gland makes a big deal in the opening paragraph of serotonin as a product of the gland. If it's true, it's a secondary or minor function of the gland and the info needs to be moved further down. I'd rather cut it out, but need to be sure. Thank you. --Hordaland (talk) 07:14, 23 May 2010 (UTC)

I know melatonin is produced from serotonin in the pineal gland. (Melatonin in retina and in the digestive tract is a different story). Serotonin is produced from tryptophan, not sure where. --Dr Dima (talk) 08:25, 23 May 2010 (UTC)

What I mean by "not sure where" is as follows. The primary location of the serotonergic neurons in the human brain is the raphe nuclei (a part of the reticular formation) in the brainstem. What I'm not sure about is whether they produce most of their serotonin locally, or whether they "recycle" serotonin that is produced elsewhere. I'm pretty sure that serotonin is produced in the digestive tract, too. How much of it is produced in the pineal gland, how much in the raphe nuclei, and how much in the gut - I do not know. --Dr Dima (talk) 08:34, 23 May 2010 (UTC)

According to PMID 8745273, serotonin is indeed released by the pineal, although its main function there is to serve as precursor for melatonin. I believe the accepted concept is that serotonin serves as an autocrine hormone (i.e., affecting the pineal itself), rather than exerting significant effects elsewhere. Certainly the pineal, being a gland, does not send specific serotonergic projections to parts of the brain, as the Raphe nuclei do. Looie496 (talk) 16:50, 23 May 2010 (UTC)

Thank you for your answers, confirming what I suspected was the case! Meanwhile, someone else has fixed that paragraph, saving me the trouble. Hordaland (talk) 20:28, 23 May 2010 (UTC)

Intramuscular fat

I'm a bit lost here, so this could be a silly question, but I'm wondering if it's possible to sort of "target" certain types of body fat, in this case IMTG, when chosing a diet? Thinking retroactively, eating chips and french fries seems to have a larger effect on visceral fat, or at least a large effect, but is there any, healthier alternative that might have less of an effect on a certain, less desirable "unhealthy" fat types, and help to produce intramuscular fat (IMTG)? This is a bodybuilding/nutrition question! 210.254.117.185 (talk) 09:24, 23 May 2010 (UTC)

The relevant article is spot reduction, which says any kind of targeted fat loss is a myth - regrettably that article is pitifully underreferenced. -- Finlay McWalter • Talk 09:37, 23 May 2010 (UTC)

I wasn't asking about fat loss, I was asking about the increase of a certain type of fat. Even if it was related (though in reverse), IMTG and visceral fat are made by a difference process, where as the article you linked talks about the same type of fat on different parts of the body. 210.254.117.185 (talk) 10:16, 23 May 2010 (UTC)

CO2 and infrared radiation

If you double the concentration of CO₂ in a glass container, say from 0.03% to 0.06% (can't think why I chose those numbers!) what happens to the percentage of infrared radiation that will be absorbed? Does it double (i.e. it's a linear relationship) or does it only increase by say 25% (i.e. it's logarithmic). Hopefully someone has actually done an experiment to show this! 131.111.30.21 (talk) 11:07, 23 May 2010 (UTC)

The answer is given by the Beer–Lambert law - assuming that the absorbtion is linear with concentration - which I'm sure it will be. Also did you mean reflection of IR (as per global warming)?87.102.18.191 (talk) 11:22, 23 May 2010 (UTC)

So the absorption coefficient will double - this means the ratio of light passing through (before and after) will be:

e^-ax / e^-2ax = e² = 7.4 times less light after doubling the concentration.87.102.18.191 (talk) 11:32, 23 May 2010 (UTC)

Yea sorry, meant reflect. Does that change the figures above? 131.111.30.21 (talk) 12:11, 23 May 2010 (UTC)

I think so yes - will have to go and check.. (hang on)87.102.18.191 (talk) 12:33, 23 May 2010 (UTC)

Actually I think I was wrong to say that reflection of IR is the factor behind global warming.

The equations for reflected light will be those of scattering - however I'm not sure if the scattering is elastic or not - I think CO2 can reflect by Raman effect at least.

Someone else will need to answer this.87.102.18.191 (talk) 13:01, 23 May 2010 (UTC)

Clarify: That would be 7.4 times less light NOT being absorbed (ie if 93% of light was absorbed before, then 7% escapes, after doubling CO2 only 1% escapes..)87.102.18.191 (talk) 13:44, 23 May 2010 (UTC)

In the case of the atmosphere the very low concentration is already enough to absorb most of the radiation so doubling makes little difference. However temperature is not relative to zero degrees Centigrade but absolute zero at -273°C so the 'little difference' can still mean a few degrees change. Dmcq (talk) 12:38, 23 May 2010 (UTC)

Where should I start?

1. Absorption of IR by CO₂ is the cause of greenhouse effect.
2. The equation used to get the figure 7.4 is completely wrong
3. The effect of the doubling of CO₂ concentration on how much IR gets absorbed depends on how thich is the path of the light through the container. If the path is thin enough that most of the radiation does get through, then doubling the concentration does double the absorption, but if the path is so thick that most of the radiation is already getting absorbed, then doubling the concentration has little effect. Think about it. If you look up at the sky through a canopy which has just a few liefs then doubling the number of liefs does double the fraction of the sky that's is covered but if you are looking through a canopy so thick that it already covers most of the sky than doubling the number of liefs has little effect.

Dauto (talk) 03:54, 24 May 2010 (UTC)

Can you explain 2 in more detail - assuming the atmosphere stays the same thickness - as an approximation, how is the Beer-Lambert law wrong here?87.102.85.123 (talk) 11:42, 24 May 2010 (UTC)

The law is not wrong. The calculation performed is wrong. Dauto (talk) 16:36, 24 May 2010 (UTC)

I see the error - the absorption coefficient doubles (?), or in the case of the equation T=I₀e^-σlN N doubles with double concentration.

So the ratio T1/T2 =

I₀e^-σlN/I₀e^-σl2N

e^-σlN/e^-σl2N

T1/T2=e^σlN

or T2=T1e^-σlN

So if 90% of the light was originally absorbed, then after doubling the concentration, a further 90% of the remaining unabsrobed light would be absorbed, or 90% of 10% - total 99% absorbtion.

Is that right?87.102.85.123 (talk) 17:31, 24 May 2010 (UTC)

Yes. Dauto (talk) 03:22, 25 May 2010 (UTC)

No, that is wrong. For the greenhouse effect, it is not relevant how much direct transmission there is ("how much sky can I see"), but how much light is transmitted at all, including diffuse light that has already interacted with one or more leafs. The canopy is actually not too bad an analogy. Even if you cannot see the sky at all, doubling the thickness of the canopy will reduce the amount of light that reaches the ground (for any given input). --Stephan Schulz (talk) 08:13, 24 May 2010 (UTC)

Yes Schultz, you're correct. I was simplifying my description to make a point. Dauto (talk) 16:36, 24 May 2010 (UTC)

Ok that makes more sense, so it is logarithmic rather than linear? Does anyone do direct measurements of infrared reflection by the atmosphere? I.e. shine an infrared laser from somewhere like Mauna Loa Observatory to a satellite and then see how this is changing over time? 131.111.30.21 (talk) 08:49, 24 May 2010 (UTC)

IR reflection is irrelevant here. IR absorption (and re-emition) is what has to be measured. Dauto (talk) 16:36, 24 May 2010 (UTC)

Yes, overall climate sensitivity is logarithmic. In other words, doubling CO2 causes an equilibrium temperature increase of 3 degrees centigrade (roughly best current estimate, but there are fairly large error bands). Note that the earth has a lot of thermal inertia, so the effect lags the cause significantly. --Stephan Schulz (talk) 14:23, 24 May 2010 (UTC)

Sneezing during examinations

The last couple of years I've been noticing that I do a disproportionate amount of sneezing about 15 minutes into an examination, and I'm interested in why this might be. I don't suffer from hay fever, and I don't sneeze a lot generally. Could it be a reaction to the stress of exams? There's nothing to sneeze - my airway isn't blocked, for example - and once it's done I generally don't sneeze again. My other thought was a slight allergic reaction to the surroundings, but I've noticed it happening in two different examination halls. Of course, it could all be down to observation bias, or any number of other biases, but I don't think it is, and it does intrigue me, so I thought I might ask. Thanks, - Jarry1250 ^{[Humorous? Discuss.]} 13:04, 23 May 2010 (UTC)

• Was it an air-conditioned room? could be adjustment to AC or just some draft. Or, perhaps, simply adjustment to sitting (as opposed to active walking etc.). East of Borschov (talk) 13:21, 23 May 2010 (UTC)

Preparation of examination rooms often requires moving furntiture etc - maybe this produces a lot of dust?87.102.18.191 (talk) 13:45, 23 May 2010 (UTC)

Yes. Inhaling dust and sneezing are inextricably linked. I would also say, normally if a person finds themselves in a dusty room, they might open a window, or leave -- but when you're writing an exam, these are not good options ("Excuse me miss, you have to hand in your test before you leave. No you may not leave the room and then return. I can't allow that."). Unable to deal with the dust in this fashion, all they can do is keep breathing it in -- and sneezing to help keep the nasal passages clear and clean. Vranak (talk) 13:59, 23 May 2010 (UTC)

Dust seems like a good suggestion, the exam tables and whatnot must accumulate a load during the year. Previous locations may have been air-conditioned, but I'm 99% sure the place I'm sitting this years isn't (they open windows, doors, etc.) - Jarry1250 ^{[Humorous? Discuss.]} 14:29, 23 May 2010 (UTC)

At my old school they placed down canvas tarpaulins on the gymnasium floor for examinations. I'm fairly sure they got no use apart from the exams in January and June, so I suspect a lot of dust would be stirred up whenever they got moved or walked on. Always had to take an anti-histamine tablet on the day of an exam, since sniffles were a problem. Brammers (talk) 10:57, 24 May 2010 (UTC)

Another possibility: Because stress stimulates the Autonomic nervous system, for example it makes you feel like you have to pee. Maybe in your case it is something similar? 195.35.160.133 (talk) 13:16, 25 May 2010 (UTC) Martin.

Why does sugar make things less sour?

So lets say you are making lemonade. Why is it that sugar makes it less sour? Does the sugar flavor overpower the sour flavor, or does it negate it? Or I should ask, would other flavors, like salt (saltiness) for example, make it less sour as well? ScienceApe (talk) 15:56, 23 May 2010 (UTC)

Sourness is due to acidity Taste#Sourness - adding sugar doesn't affect the acidity. Lemonade sourness is in part due to the citric acid , and also due to dissolved carbon dioxide (if it's fizzy type). There's not a reaction between sugar and citric acid to be expected in lemonade (though it could possible esterify) I'm fairly certain it is a masking effect.87.102.18.191 (talk) 16:25, 23 May 2010 (UTC)

Sweetness competes with each of the other basic tastes (sour, salty, bitter), in the sense that increasing sweetness reduces the perception of the others, and increasing the others reduces the perception of sweetness. A notable example is tonic water, which doesn't seem sweet to many people even though it is almost gooey with sugar. I'm not sure whether the other basic tastes compete with each other (sour versus bitter or sour versus salty, for example). Looie496 (talk) 16:39, 23 May 2010 (UTC)

There's a significant difference between the taste of "straight" tea and coffee, which tend to be bitter, vs. adding sugar to them. The one I'm not sure you can do much about is saltiness. I can't think of any obvious way to counter saltiness other than simply diluting it (as you could with the other items as well). ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:30, 23 May 2010 (UTC)

The old wives' way of adding a potato to oversalted stews (and then discarding the potato, which will have absorbed the excess salt) does work. Never tried it for anything else, though. --TammyMoet (talk) 09:59, 24 May 2010 (UTC)

Has anyone seen Neptune with the naked eye?

Although it is commonly claimed that Neptune is too faint to be seen with the naked eye, this is not really true.

Brian skiff has tried but he failed to see it. The conditions were not optimal as Neptune was low in the sky. He claims that from the Southern Hemisphere it would be straightforward to spot. So, this suggests that there should be quite a few (amateur) astronomers with excellent eyesight who have seen it, but I haven't seen any such claims. Count Iblis (talk) 17:53, 23 May 2010 (UTC)

At a magnitude of ~8-7.78, it would require exceptional conditions to see it: an experienced astronomer who knows how to look for faint objects, exceptionally clear sky, hundreds of kilometers from any city, and knowing exactly where to look. Even if you could, by some miracle, manage to see it, I'm not sure that you could distinguish it from any other faint star out there. Do you know the positions of the tens of thousands of stars at least that bright with a high enough degree of precision to distinguish one barely visible point of light from another one? As the forum points out, even Uranus, with a magnitude of up to 5.32, and 4 Vesta, of magnitude up to 5.1, were not discovered and named until telescopes were around. I would hazard a guess that most celestial objects dimmer than magnitude 5 were not cataloged and named until after the invention of the telescope. Now granted, "named and recognized" is not the same thing as "ever seen", but if you can't recognize a faint dot as Neptune, do we really count that as "seeing" it? Buddy431 (talk) 18:22, 23 May 2010 (UTC)

Yes, "seeing Neptune" with the naked eye would be a tour de force involving detailed star charts and identifying all the brighter objects in the immediate neighborhood. But note that quite a few (amateur) astronomers do exactly this sort of a thing as a sport, but usually for spotting Messier objects with the naked eye. They keep logs of successful naked-eye observations, see e.g. here. So, given this dedicated effort, I find a bit strange that only [Brian Skiff's report] of his failure to see Neptune exists. Count Iblis (talk) 00:24, 24 May 2010 (UTC)

Incidentaly, Wikipedia doesn't have a comprehensive list of astronomical objects (or even stars) by magnitude that's very good. We have the List of brightest stars going down to magnitude 2.5. It would be nice if we could get lists for the other ranges (i.e. List of stars with magnitude 2.5-3.5, list of stars with magnitude 3.5-4.5, etc). If there are machine readable star catalogs available, such lists could be made with some sort of bot. Of course, such lists may be seen as "indiscriminate" by the deletionists here... Buddy431 (talk) 18:49, 23 May 2010 (UTC)

The problem with such a table is that the number of stars at magnitude X grows exponentially in X (there are roughly 3 times more stars with magnitude 2.5-3.5 than with magnitude 1.5-2.5, and another 3 times more with 3.5-4.5). So you get into really large numbers really fast - and I suspect for most of these stars we have very little information. --Stephan Schulz (talk) 11:41, 24 May 2010 (UTC)

I'm envisioning something along the lines of our list of minor planets. There's only about 10,000 stars in the Bright Star Catalogue (as opposed to 200 000 minor planets...), which would easily be manageable if broken into sets of 1000 or so. Even the Henry Draper Catalogue "only" has 350 000 entries: I imagine some sort of manipulatable list could be created from it too. It looks like the astronomy club here is currently trying to improve the table for their minor planets: maybe I'll drop by and try to urge them to work on stars next (I know, I know, or I could do it myself... much too lazy for that). Buddy431 (talk) 16:57, 24 May 2010 (UTC)

No fish

Is there a term for someone who eats meat, fruit and vegetables but doesn't eat any fish? Servien 18:47, 23 May 2010 (UTC)

Closest I've found so far is Pollotarianism, which excludes fish and mammals. Vimescarrot (talk) 18:53, 23 May 2010 (UTC)

Are there enough people that fit that description to warrant having a name for it? --Tango (talk) 19:17, 23 May 2010 (UTC)

I know two. They can eat mammals such as whale but are highly allergic to all fish (salt water and fresh), seafood and crustaceans. It is one of the nine most common food allergies. Kittybrewster ☎ 19:29, 23 May 2010 (UTC)

Reverse pescetarian? Clarityfiend (talk) 20:23, 23 May 2010 (UTC)

How does anti-pescatarian sound? Or just apescatarian. Vranak (talk) 21:03, 23 May 2010 (UTC)

Like they wouldn't eat fruits or vegetables either. Clarityfiend (talk) 21:09, 23 May 2010 (UTC)

Pesca- just means fish though. Apesca = no fish. Vranak (talk) 21:33, 23 May 2010 (UTC)

Heh, nice term. I guess that applies to me. I eat meat, vegetables and fruit, but I'm not a fan of fish so I don't eat it. Regards, --—Cyclonenim | Chat  22:33, 23 May 2010 (UTC)

Of course it's hard not to notice that the first part of the term forms the words ape scat. Vranak (talk) 22:47, 23 May 2010 (UTC)

Jane Brody has used the term "pescaphobia". Looie496 (talk) 22:58, 23 May 2010 (UTC)

That implies an irrational fear of fish, but if one is allergic, it's a rational fear, and if one simply doesn't like the taste of fish, that's neither irrational nor a fear, it's just personal preference. That does not preclude the possibility that there could be some having an irrational fear of fish. However, terms like vegetarian and vegan are preferred over "carniphobia" or whatever the equivalent would be. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:03, 23 May 2010 (UTC)

So there simply is no official term for a "no-fish eater"? Some time ago I thought of the term anichthyophagist the verb beeing anichthyophagia (from Latin) Sεrvιεи | T@lk page 20:51, 25 May 2010 (UTC)

Bird call

What bird is this? http://commons.wikimedia.org/wiki/File:Unknown_bird_call_MN_052210.ogg

Taken 2010-05-22 in Interstate State Park. I was not able to see the bird making this call (all weekend!).

-Ravedave (talk) 20:37, 23 May 2010 (UTC)

Dragons

Are we absolutely sure that dragons have never existed? I find it interesting that almost every part of the world has stories about dragons of some form or another. Seems strange for something that was never real. If there *were* dragons (not saying fire breating and flying, which AFAIK would be impossible - just really big carnivorous reptiles, or even the long, thin, Chinese-style water-based ones) and their numbers were declining at around the same time that humans were becoming civilized, and the last few had been wiped out before 1000AD (say), would there even be any ovbious evidence today of their existence? Just curious. --95.148.108.186 (talk) 21:06, 23 May 2010 (UTC)

If they don't breathe fire or fly, why would anybody call them dragons instead of "just really big carnivorous reptiles"? Clarityfiend (talk) 21:14, 23 May 2010 (UTC)

Because they were stories of heroism that were exaggerated in the telling and re-telling? Going from a dinosaur/big lizard-like creature, to something with borderline magical powers? Don't know really, I was just thinking on the screen. :) --95.148.105.95 (talk) 21:25, 23 May 2010 (UTC)

Really big carnivorous reptiles? Like crocodiles and alligators? Or dinosaurs? They definitely exist(ed). --Tango (talk) 21:20, 23 May 2010 (UTC)

Or Pterosaurs? ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:45, 23 May 2010 (UTC)

Or Komodo dragons? "really big carnivorous reptiles" ... check, check, and check. We even call them "dragons". -- 174.24.200.38 (talk) 01:24, 24 May 2010 (UTC)

I believe the biggest issue is that dragons have, by classical definition, six appendages (four legs and two wings), while (and correct me if I'm wrong), all other higher land-going lifeforms have four. Snakes of course don't count; they have none. But six, no, that just doesn't seem feasible from an evolutionary standpoint. And then there's the small matter of there being no fossil record of such a thing. Vranak (talk) 21:31, 23 May 2010 (UTC)

Take a look at draco (genus). Looie496 (talk) 22:54, 23 May 2010 (UTC)

Fair enough! I'll revise that 'classical definition' then -- four legs and flappable wings, for more than just gliding. Vranak (talk) 23:19, 23 May 2010 (UTC)

two points, both from Dragon

• in Origin and Etymology "Dinosaur and mammalian fossils were occasionally mistaken for the bones of dragons and other mythological creature; for example, a discovery in 300 BC in Wucheng, Sichuan, China, was labeled as such by Chang Qu...." ... more in that section
• in Dragon#Indian , after removing hyperbole, appears to be a description of a Python

Anyway , if it didn't exist you'd have to invent it .. those long cavemen evenings without TV, and kids always asking "what is there over there/below"87.102.18.191 (talk) 21:37, 23 May 2010 (UTC)

I'm also likely to believe the idea of dragons being an exaggerated folk memory (of v. big snakes and crocs) - reason - apparent absense of dragon myths in countries that do have big snakes and crocs.87.102.18.191 (talk) 21:43, 23 May 2010 (UTC)

Folk memory, yes. Perhaps as with other mythical creatures, e.g. the unicorn. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:47, 23 May 2010 (UTC)

They probably come from descriptions of rhinoceri. (original research?) --Kurt Shaped Box (talk) 21:54, 23 May 2010 (UTC)

I've heard that theory before. And there typically weren't any rhinos in Europe, just the Rhineland, which is unrelated as far as I know. There's a much more modern analogy, though, and that is the current stereotype of what flying saucer aliens look like, i.e. like the characters in Close Encounters and E.T., which apparently evolved over time from the appearance of primitive crash-test dummies used in high-stratosphere balloon tests. This contrasts with The Day the Earth Stood Still, where the aliens looked like Michael Rennie. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:00, 23 May 2010 (UTC)

Which, trust me, was a lot more scary. HalfShadow 22:01, 23 May 2010 (UTC)

Yep. Klaatu barada nikto, and all that sort of thing. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:03, 23 May 2010 (UTC)

I have to ask -- I know this phrase from Army of Darkness, but does it have any deeper/earlier meaning? Vranak (talk) 23:18, 23 May 2010 (UTC)

We have an article on it, which I've now linked. Without looking at it first, I know "Klaatu" was the name of the alien played by Michael Rennie, and the whole phrase was spoken to the robot Gort, which somehow told him where to find Klaatu. That's a lot of info to be contained in 2 words, but the robots were programmed with a series of commands which were like shorthand of some kind. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:26, 23 May 2010 (UTC)

An excellent book on the subject is The Natural History of Unicorns by Chris Lavers. The Indian rhinoceros certainly played a part in the creation of the unicorn, but it's an extremely complicated tapestry that includes several animals native to central Asia, including the chiru. The interesting thing about the unicorn is how sure everyone was that it existed. Our article on Harry Johnston notes that "[H]e was instrumental in bringing the okapi to the attention of science", but he wasn't wandering Africa looking for the okapi - he was searching for the unicorn. And why look in Africa when all the stories said it came from Asia? Because it had to live somewhere and Africa was the only place left to look... Matt Deres (talk) 01:14, 26 May 2010 (UTC)

Also note that different parts of the world having stories about "dragons" is not terribly telling. A Chinese dragon isn't all that similar to a European dragon other than the fact that they're both mythical reptiles. Do big, scary (or auspicious, depending on your point of view) exist? Absolutely. Buddy431 (talk) 23:01, 23 May 2010 (UTC)

I have heard it proposed, though not directly by the experts of the field, that it goes way back. When our mammalian ancestors were evolving, there were still dinosaurs around. It would stand to reason that early mammals would have been extraordinarily cautious about large carnivorous reptilian animals. The theory that was proposed is that the reason that many human cultures have a dragon of sorts is just because those descriptions stand out to us on residual instinct. Now is that likely after 65 million years? I have no clue, maybe someone else can comment. Falconus^{p t c} 00:27, 24 May 2010 (UTC)

Hey, this seems to be directly related to what I just said above. An Instinct for Dragons.Falconus^{p t c} 00:33, 24 May 2010 (UTC)

I try to refrain from just giving comments which don't add to the discussion, but i have to say the above is just absolutely fascinating! What an amazing hypothesis. Vespine (talk) 00:55, 24 May 2010 (UTC)

I also heard that theory long ago. I think it was termed "racial memory". It seems a little far-fetched. However, humans often show a fear and distrust of reptiles in general, including the serpent in Genesis as just one example. Whether that's "racial memory" going back to times when mammals and dinosaurs may have co-existed, or if it's just good sense, is hard to say. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:36, 24 May 2010 (UTC)

On the subject of "pre-programmed" fear or knowledge of serpents - the plant/drug Yage is commonly reported to produce hallicinations of predators such as big cats/snakes.. even in people brought up in countries with no such thing [1] (also [2]) (it was reported possibly less reliably by Terence McKenna that even eskimos hallucinate cat predators under it's influence) If that is someway related to some sort of built in DNA memory of giant reptiles is tenuous .. It's not as far as I know been shown that people with no concept of cats / snakes hallucinate them under it's influence. Probably irrelevant.87.102.18.191 (talk) 01:33, 24 May 2010 (UTC)

Right. It is highly doubtful the "genetic memory of the dinosaurs as the arch-nemesis of humans" hypothesis has any merit at all. At the time dinosaurs went extinct our ancestors were not even monkeys; actually, at the time of the last dinosaurs the lemurs and the tarsiers did not yet split into separate lines (we are on the "tarsier" line, haplorrhini, in case you wonder). Big cats, hippos, and early hominids / humans were and are until this day a much more real and a much more present threat to our ancestors. Yet we do not have much of a natural fear of cats, large herbivores, or other people. What humans usually fear are bacteria, viruses, cockroaches, snakes, and spiders. People go to the zoo to see the tiger; people run away when they see a garter snake. A flying snake should be an outright nightmare. Hence, I guess, is the dragon. --Dr Dima (talk) 01:36, 24 May 2010 (UTC)

There are plenty of tropes which tend to occur independently in all sorts of cultures and stories. Like superhuman strength - how many people do you think in the history of man have been carrying something and thought it would be really neat if they could pick up the whole load in one hand? Or flight - all kinds of legends and myths talk about people soaring through the sky, not because humans ever had the ability to fly, but because it's almost universally held that it would be awesome. ZigSaw 11:51, 24 May 2010 (UTC)

Here's the problem with dragons. It's sometimes mooted that dragons are a universal or near-universal fixture in myths around the world. For that reason, ridiculous books like the afore-mentioned An Instinct For Dragons get published to account for this "fact". The only problem is that there is no such fact - it's complete baloney. Dragons have no legs, two legs, four legs, more legs; dragons have no wings, two wings, four wings; dragons are scaly like snakes, leathery like rhinos, slimy like worms, feathered like birds; dragons are small-ish, large animal sized, huge, the size of islands; they breathe fire, they breathe poison; they have one head, they have seven heads, they have nine heads; their tail is forked, their tail is like a snake, their tail is like a fish; they're benevolent, malevolent, and indifferent. The problem is that "dragon" is a catch-all term for all sorts of vaguely reptilian monsters. If these monsters had all kept their original names, people might be less inclined to explain their universality. Matt Deres (talk) 20:28, 25 May 2010 (UTC)

Yes, that is quite true. Dragons would have been a Wastebasket taxon if they were real; them being mythological, they are just dragons :) . There were actually attempts in Middle Ages to "classify" dragons. If my memory serves me well, you can find a stealth parody of that in The Hobbit, where Tolkien goes into great detail of how Smaug is unlike the other dragons, even though Smaug is the only dragon to actually appear in The Hobbit. But yes, again, you are right, there are Chinese dragons (many kinds, always one head, mostly terrestrial or "celestial", usually benevolent), Japanese dragons (one head, mostly aquatic), Ukrainian dragons (three heads, one body, fire-breathing), Norse dragons, Biblical dragons, Hittite dragons, wyverns, and so on in the myths of the various nations. They all look more or less like flying snakes or flying crocodiles, which should be a Bad Thing in itself; but beyond that every nation or group of nations basically comes up with an idea of its own about what it may look like and what it could do. --Dr Dima (talk) 21:57, 26 May 2010 (UTC)

over eating

If a person is disabled or older they cannot do as much exercise as may be needed for weight control. Therefore weight control is dependent on not over eating. Yet because the human body requires so little food it is very easy to over eat. Is there a pill or other means of controlling appetite so that a person will not over eat due to a feeling of hunger? 71.100.3.228 (talk) 21:24, 23 May 2010 (UTC)

There are lots of appetite suppressants available. I won't comment on their efficacy or safety, but they certainly exist. --Tango (talk) 21:45, 23 May 2010 (UTC)

What about other means besides pharmaceuticals? Are their foods or other means to control or eliminate appetite? 71.100.3.228 (talk)

I've heard of the opposite effect, i.e. that places like McDonalds used to put chemicals into your food which made you feel full slower, and thus more likely to buy more food. Regards, --—Cyclonenim | Chat  22:31, 23 May 2010 (UTC)

Regards what? 71.100.3.228 (talk) 04:27, 24 May 2010 (UTC)

"Regards" is a formal way of ending a letter. I don't see it much in Web postings, but that's what Cyclonenim meant. Comet Tuttle (talk) 06:58, 24 May 2010 (UTC)

It works better for starting threads than replying to them, but it's part of the signature and I sure as hell can't be arsed to write it out every time (i.e. think when it's needed). Regards, --—Cyclonenim | Chat  07:32, 24 May 2010 (UTC)

When I see it at the end of a web post I'll continue then to append (the word) nothing. 71.100.3.228 (talk) 08:47, 24 May 2010 (UTC)

User:SqueakBox signs off with "Thanks". Kittybrewster ☎ 10:59, 25 May 2010 (UTC)

Studies have shown that the feeling of satiety comes from the bulk and weight of food, not calories. Eat lots of vegetables and fresh fruits - bulk and weight without much calories - and wheat- or oat-fibre too to fill you up. Avoid foods containing fat, especially saturated fat (although a small amount of fat is required for health). See http://www.nutritiondata.com/topics/fullness-factor After a few months you will prefer healthy food and be disgusted by fatty junk food. 92.28.255.202 (talk) 22:24, 23 May 2010 (UTC)

Byetta is a powerful appetite suppressant, which also delays emptying of the stomach. It is presently commonly used as a prescription drug for Type 2 diabetics, but might be the next big weight loss drug. The article notes some undesirable side effects of the drug. Edison (talk) 00:44, 24 May 2010 (UTC)

For severe cases of obesity, where the standard advice of diet and exercise does not work, bariatric surgery has been used to reduce the size of the stomach. A smaller stomach means that less food is needed to obtain satiety. -- 174.24.200.38 (talk) 01:20, 24 May 2010 (UTC)

The diet market is massive, so you'll hear hundreds of claims of "miracle diets" and "pills". Even moderate exercise can help though. Under normal conditions weight gain or loss is down to the amount of energy you use, minus the energy you take in from food (calories). You can increase your use of energy as well as decrease your intake and it works very well. FT2 ^{(Talk | email)} 04:17, 24 May 2010 (UTC)

This remedy is where the problem begins... exercise only increases hunger making the task to reduce intake even harder. 71.100.3.228 (talk) 04:25, 24 May 2010 (UTC)

No, I read about a study which said that although people did eat more after exercise, the extra calorie intake was still less than that expended. So there is no excuse for not exercising. Never mind the drugs - a simple thing to do, without possible bad side-effects, is to make sure you eat enough fresh vegetables and fruit each day. Something that may block this is that many people in my experience do not know how to do simple cooking, such as boiling vegetables (cut into chunks and put in a saucepan of boiling water for a few minutes until tender), and so have to buy junk food instead. 92.28.251.49 (talk) 11:13, 24 May 2010 (UTC)

The reason I disagree with this study is that walking a mile only burns about 50 calories and jogging only about 90. Only athletes able to jog 10 miles can expect to burn off 900 calories. Most people do not have the time or inclination to jog 10 miles every day so its back to not overeating as the main way to lose or not gain weight. 71.100.8.229 (talk) 20:25, 25 May 2010 (UTC)

Nevertheless, excercising is good for you. Not exercising considerably raises your chances of getting seriously ill and having a reduced lifespan. 92.28.240.102 (talk) 22:50, 25 May 2010 (UTC)

I agree that exercise is good for you and you should do a program that gets round to every single muscle but not do exercise only to burn calories. People who do exercises only to burn calories fall into the group of mammals with a higher metabolism and shorter lifespan. 71.100.8.229 (talk) 08:40, 27 May 2010 (UTC)

Hunger is a very inaccurate sensation. People tend to feel hungry if they haven't eaten what their body is used to them eating at a given time of day. The calories you actually need are a very small factor in determining hunger. That means you generally don't feel significantly more hungry if you increase your activity (of course, if you try and run a marathon you are going to notice a need for extra calories, but small changes can easily go unnoticed). --Tango (talk) 00:33, 25 May 2010 (UTC)

Compare the fact that you can easily get 105 calories from a single medium size banana which will require 2 miles of walking to burn off and you see clearly that exercise is not the solution but rather that not overeating is. 71.100.8.229 (talk) 20:28, 25 May 2010 (UTC)

I am not sure that you can write off exercise so easily. What would be the effect of walking 2 miles extra each day? I expect it would lead to an increase in muscle mass, which would increase your calorie requirements. -- Q Chris (talk) 13:33, 26 May 2010 (UTC)

help pLz \\ drugs used in managment of infusion

describe the drugs used in managment of infusion - related to side effects —Preceding unsigned comment added by Mrmr-rana (talk • contribs) 21:33, 23 May 2010 (UTC)

You're going to need to be much more specific if you want a meaningful answer. What type of infusion do you mean? Also note that we cannot give medical advice on the reference desk. If this is about a treatment you or someone you know is undergoing, you should talk to the doctor who's administering the treatment. Buddy431 (talk) 22:56, 23 May 2010 (UTC)

Possibly means "Blood infusion" ie Blood transfusion - an anticoagulant is Heparin, Paracetamol is used if minor side effects occur [3] not a medician so don't know much more.87.102.18.191 (talk) 00:32, 24 May 2010 (UTC)

This looks more like a homework question than a request for medical advice to me. AndrewWTaylor (talk) 08:18, 24 May 2010 (UTC)

I really hope it is, I'd hate for the triage nurses to have brought in a wireless laptop just to have the physician's Reference Desk question get rejected ZigSaw 11:39, 24 May 2010 (UTC)

Tiny bullet-shaped dog

I saw the tiniest dog I've ever seen being taken for a walk recently. It was white and bullet shaped, with the head forming the curved cone-like front of the bullet. Moving at walking pace, its little short legs were a blur, as its stride could only have been one or two inches. It was not a sausage-dog or a chichua. It did not behave like a puppy, but like a disciplined fully-grown dog. What breed could it have been? 92.28.255.202 (talk) 22:21, 23 May 2010 (UTC)

Sounds more like a pet guinea pig to me. 71.100.3.228 (talk) 22:38, 23 May 2010 (UTC)

or White rat on a lead ? (it happens).87.102.18.191 (talk) 22:44, 23 May 2010 (UTC)

What was its coat like? And it's not a Scottish Terrier is it? Vranak (talk) 22:46, 23 May 2010 (UTC)

It was not a guinea pig or a Scottish terrier. It had short fur. 92.28.255.202 (talk) 22:49, 23 May 2010 (UTC)

Sure it wasn't a ferret? --Kurt Shaped Box (talk) 22:51, 23 May 2010 (UTC)

It was definately a dog, and not a rat or ferret. 92.28.255.202 (talk) 22:53, 23 May 2010 (UTC)

Try teacup dog. 71.100.3.228 (talk) 23:06, 23 May 2010 (UTC)

It may have been something like a Bull Terrier (Miniature) except it had no neck, and shorter legs. Apparantly there are "designer dogs", so perhaps it had been specially bred to be super-tiny. 92.28.255.202 (talk) 23:14, 23 May 2010 (UTC)

Maybe a Pomeranian (dog)? —Preceding unsigned comment added by 86.4.186.107 (talk) 07:52, 24 May 2010 (UTC)

In case you haven't found it yet, the article on List of dog breeds gives you loads of pictures. If you were in Yorkshire, it's likely to have been a ferret.--Shantavira|^{feed me} 08:48, 24 May 2010 (UTC)

It was not a pomeranian as it did not have a fluffy coat, and a pomeranian is not bullet shaped either. Perhaps I underestimated the stride - it may have been more like three inches. I have seen ferrets being taken for a walk on one or two other another occassions, and it was definately not a ferret. If miniature Bull Terrier puppies have short legs and no neck, then it could have been one of them. As it had to concentrate on moving its little short legs as fast as propellors, then it may not have had time to indulge in the usual romping puppy behaviour. My best guess is that it was a cross between a minature Bull Terrier and some other minature dog that gave it tiny legs and no neck. 92.28.251.49 (talk) 11:00, 24 May 2010 (UTC)

These are miniature bull terrier puppies. I don't know if they're what you saw, but they I do know that they are adorable. --Mr.98 (talk) 15:51, 24 May 2010 (UTC)

Next time, ask the person who is walking the animal. Failing that, a photograph would be more useful than any verbal description. --Teratornis (talk) 19:43, 24 May 2010 (UTC)

No, really? 92.28.244.102 (talk) 10:44, 25 May 2010 (UTC)

In any case, it might not be a recognized breed at all—it could be a mixed-breed dog. --Mr.98 (talk) 21:45, 24 May 2010 (UTC)