Wikipedia:Reference desk/Archives/Science/2011 October 10

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October 10

Lightning and auroras

Hi. I'd like to know more about the interaction of upper-atmospheric lightning and tropospheric-origin electrical discharges, including elves, sprites, jets, gamma-ray flashes and antimatter generation events, with the lower-ionospheric geomagnetic aurora activity, which can extend down to 35 km altitude. In particular, are there any effects of interaction, which could be rare since strong thunderstorms and auroras are differentiated by latitude, but do effects occur that either change the atmospheric composition or channel energy from the Earth's geomagnetic field and solar wind, including its ionizing radiation and magnetic anomalies, down to the Earth's surface through lightning discharge or other phenomena, including plasma radiation? Please also link to any relevant scientific journal articles, and in particular the information found in Schumann resonances may be relevant. Thanks. ~AH1 ^(discuss!) 00:46, 10 October 2011 (UTC)

Please correct me if I've missed your point, but are you asking for scientific information about how elves and sprites effect the weather and the aurora borealis? Beeblebrox (talk) 20:18, 10 October 2011 (UTC) Never mind, it appears these terms are actually used by science to describe u-a lightning events. How silly of them. Beeblebrox (talk) 20:20, 10 October 2011 (UTC)

The etymology is a tongue-in-cheek reference to the history of these events. When atmospheric scientists started reporting unexplainable bright flashes in the night sky, naturally everyone jumped to the UFO conclusion. It took several decades before scientific reports about sprites, jets, and elves, were taken seriously. Nimur (talk) 16:48, 11 October 2011 (UTC)

My understanding is that these sorsts of things are effects of lower level storms, not causes in themselves. See http://en.wikipedia.org/wiki/Upper-atmospheric_lightning#Elves to begin with. Let us know if you have more questions. μηδείς (talk) 07:15, 11 October 2011 (UTC)

Here is a listing of textbooks from some of the world's preeminent experts on electromagnetic interactions between the troposphere and the ionosphere/magnetosphere: books published by Stanford Very Low Frequency Group. There are also numerous research publications on the electromagnetic and particle interactions between tropospheric lightning and transient luminous events in the ionosphere: complete publication list. Consider, for example, Optical signatures of lightning-induced electron precipitation. These are, needless to say, technical papers. Nimur (talk) 16:48, 11 October 2011 (UTC)

Modified HIV-based cancer vaccine

Can someone please explain in laymans' terms how http://www.msnbc.msn.com/id/44090512/ns/health-cancer/t/new-leukemia-treatment-exceeds-wildest-expectations/ works? Why do the modified white blood cells start killing cancer? Are they trained to produce 3-BrPA when they taste cancer cells? 208.54.38.211 (talk) 02:57, 10 October 2011 (UTC)

White blood cells are a key component of the immune system, which recognize foreign cells and begin the process of their destruction. So when you have a cold or other infection due to some bacteria or other invader, the WBCs attack. One problem with cancer is that cancer is in many ways our own cells, so our own immune system does not recognize it as a foreign threat--if our immune system turns against our own cells, we are in serious trouble (see Autoimmune disease)! So a scientific advance is to train some WBCs (in particular, T cells) to recognize the cancer cells as foreign but distinguish them from non-cancerous cells.

In addition, WBCs only live for a few days. That's not a problem usually, because our bone marrow constantly produces new ones (in part adapting/responding to novel foreign invaders that may be detected). But special WBCs produced in a lab would not by regenerated because the marrow itself (in the body) was not altered to produce more of them--the body only contains as many as were injected for as long as that batch lives. Another scientific advance here was to make the anti-cancer WBCs able to replicate after being injected. DMacks (talk) 09:21, 10 October 2011 (UTC)

Actually, they don't kill cancer - they kill B cells of any kind. Chronic hypogammaglobulinemia is a side effect. For people within weeks of death, this is a tremendous advance, but it is a drastic treatment. Wnt (talk) 13:16, 10 October 2011 (UTC)

By B cells do you mean B-lymphocytes? I like the idea of merely training the white blood cells to produce anti-cancer agents around cancer cells instead of treating them as foreign (although if that could happen too, all the better.) Ad astra. 69.171.160.57 (talk) 15:53, 10 October 2011 (UTC)

Human Sensitivity to IR

Generally, I think, human beings are not sensitive to Infrared rays. Is it possible that some disease or deformation or DNA defect can make a human being sensitive to infrared rays.  Jon Ascton  (talk) 03:51, 10 October 2011 (UTC)

The receptivity of the human eye is actually a bell curve (three of them, actually), and a very tiny portion of the thin part of the bell curve is actually in the spectrum we call "infrared". this person found that by wearing goggles that completely blocked out the visible light, and then went out into bright sunlight, he could see a little bit of infrared. APL (talk) 04:18, 10 October 2011 (UTC)

That would have been near-IR, though. Not the kind of IR used in thermal-imaging. If the OP wants that kind of IR, then it's pretty much impossible - you would have too much interference from the IR the eye itself is emitting (although, I suppose there's no fundamental reason the eye couldn't be cooled to below usual skin temperature - it would require some pretty major evolutionary changes, though). Radio telescopes have the same problem - they need to be cryogenically cooled in order to avoid emitting too much radition in the part of the radio spectrum that they are trying to observe. --Tango (talk) 11:41, 10 October 2011 (UTC)

The only animals that can "see" in the infrared range, as far as I know, are certain types of snakes, and they use a special sensory system called a pit organ to do it, not their eyes. There are a variety of biophysical issues that make it nearly impossible for an eye-like mechanism to function well in that frequency range. Looie496 (talk) 15:36, 10 October 2011 (UTC)

I'm not sure the OP meant "seeing IR" when he said "being sensitive to IR." He could be thinking about something like light allergy, but against heat. Quest09 (talk) 15:46, 10 October 2011 (UTC)

Hold a warm object close to your lips. Can you feel the heat (infra red radiation)?--92.28.77.67 (talk) 16:04, 10 October 2011 (UTC)

Yes, but feeling is not "being sensitive." "Being sensitive" for me is being harmed/annoyed when in contact. Quest09 (talk) 16:55, 10 October 2011 (UTC)

The OP didn't say 'being sensitive', they said 'a human (being) sensitive to infrared rays'. Nil Einne (talk) 18:27, 10 October 2011 (UTC)

Thanks all. To be precise : when we press a button on a TV's remote control it emits IR from it's IR LED at front. That's invisible to human eye i.e. both the source of IR (LED) or any surface reflecting it. Is there any special biological defect that can make a man see it ?  Jon Ascton  (talk) 00:51, 11 October 2011 (UTC)

No (and, if they could, I wouldn't call that a "defect"). StuRat (talk) 01:36, 11 October 2011 (UTC)

I'm not sure what you really mean when you say that ! But I know a man who claims to see a very faint tinge of redness when his eyes are fully relaxed (i.e. after sleeping etc.) Could be a technical defect in IR LED ?  Jon Ascton  (talk) 02:37, 11 October 2011 (UTC)

Very likely. A lot of infrared LEDs will put out some light that's just barely in the "visible red" area. After your eyes have been closed for more than a couple minutes your eyes become completely dark-adapted, and that's when you're most likely to notice a very dim light. Your friend would probably be able to duplicate this effect when not tired by sitting in a completely dark room for ten minutes.

I used to use a bunch of cameras that had bright IR illuminators on them, and they had a faint visible-red glow. APL (talk) 06:35, 11 October 2011 (UTC)

Plenty of hotels have IR bulbs which you can sense via the skin even if you are blind. μηδείς (talk) 07:06, 11 October 2011 (UTC)

How a Latino could not be a Caucasien?

Hi clever people, please excuse my poor English, I'm French. Recently in the TV-serie "BONES" they find 2 corpses and the gifted Dr Brennan says "One is a Latino the other one is a Caucasian". I thought that Caucasian in American means something as White or European to indicate the difference with "Negro" or "Asian" and so on. And so for me Spaniards are obviously white, european Caucasians.

Question : What is this thing that I don't understand? Latinos have Spaniards ancestors, why not including them among the Caucasians? Thanks a lot for reading. Joël Deshaies-Rheims-France---85.170.172.37 (talk) 10:14, 10 October 2011 (UTC)

There is certainly some confusion regarding the term Latino: sometime it depicts a culture (Latin-American) and others it depicts a phenotype (native Indians of Latin-American and its descendents). Quest09 (talk) 10:29, 10 October 2011 (UTC)

Africans, brought to the Americas, and currently from Central/South America are referred to as Latino. They are not of Spaniard/European descent. To complicate it further, whites, from the same area, are referred to as Latino. The native people, from the same area, are referred to as Latino. Pretty much, anyone from Central/South America is considered Latino. In U.S. Government forms, Latino/Not Latino is asked separately from Race. So, you can be White Latino, Black Latino, or even Asian Latino. -- kainaw™ 12:37, 10 October 2011 (UTC)

All of that is true, and also there was a tremendous amount of what is politely called intermarriage between the Spanish colonists and both the native people and African slaves. The conquistadors did not bring wives with them to the new world, and they were active in territories that tended to have a higher population of Native Americans than the territories settled by English-speaking colonists.thx1138 (talk) 15:39, 11 October 2011 (UTC)

Race is a peculiar concept. I've read that the term "Hispanic" was coined by the United States Office of Management and Budget in 1978, [1] with "Latino" becoming popular shortly afterward - before then, curiously enough, according to the article it was used by people of certain politics to express affinity between Mexicans and French who were involved there. How "Latino" excludes Latium, I don't know; Italians are right out. In practice I think the term largely means people with a family history of speaking Spanish. What's funny is that white x black = black, and anything x "Hispanic" = "Hispanic" - unsurprisingly there are continually "news reports" that Hispanics are the "fastest growing minority" taking over the country. It is amazing how much weight can be placed on imagination and semantics. Wnt (talk) 13:30, 10 October 2011 (UTC)

I'm from Brazil and consider my self Latino, but not Hispanic. I've met some Italians that felt the same way. Dauto (talk) 14:46, 10 October 2011 (UTC)

Latino means actually from 'Latin(o)-America' in most cases. That would exclude people like Italians and such. If it means from from the Latium, it would include Italians. The word is simply ambiguous. Quest09 (talk) 15:51, 10 October 2011 (UTC)

In a context of forensic anthropology, "race" is usually just a way to say, "here's what an average person in this culture would think about this person." That's really all. So if I were to find a skeleton with certain facial characteristics, I'd be able to say, "oh, this looks more or less like someone who has a lot of their ancestry derived from people who lived on this continent." A shorthand of which is to say, "black" or "white" or "Asian" or "Latino" or what have you. From a strictly taxonomical point of view, this is a very problematic statement. But from the perspective of, "can we match this skeleton up to a number of possible missing people?", it's very useful. This is, anyway, what I gleaned from talking with a number of forensic anthropologists awhile back. So if I heard a forensic anthropologist in the United States say "this skull looks Latino," I'd assume, "this person looks like they have ancestry that was from South America, which is probably some form of European-Indian mix." If they said they were just "Caucasian," I'd assume they meant, broadly, "a very European looking skull." The skull would tell you exactly zero about what languages they spoke, what holidays they practiced, etc., obviously. I've of course no knowledge of what was necessarily meant by a fictional television show. --Mr.98 (talk) 16:53, 10 October 2011 (UTC)

Broadly, latino does mean of some nationality descended from the Romans, especially speaking a language descended from Latin. If you use Google translate from Spanish to Italian, latino translates as latino. Plenty of European Italians and others self identify as latino. Rudy Valentino was the "Latin Lover" in English but the amante latino in both Spanish and his native Italian. That being said, in the US, Latino usually means Latin American, specifically Spanish or even Luso-American and applies not only to Europeans but blacks and native Americans from Spanish American nations, and even, Brazilians. μηδείς (talk) 07:04, 11 October 2011 (UTC)

• So, to answer the question, the good Dr Brennan could probably identify a caucasian from their skull shape, but could only identify the other set of bones as latino if she had access to a good spae wife Elen of the Roads (talk) 15:51, 11 October 2011 (UTC)

Many Latin-Americans have mixed ancestry, similar to the Métis in northern North America; some are descended from the Aztec, Maya, Incas and other indigenous peoples of the Americas. ~AH1 ^(discuss!) 23:51, 14 October 2011 (UTC)

hydrogen peroxide

Does the regular 3% peroxide kill fungal spores such as ringworm spores? — Preceding unsigned comment added by 66.209.177.15 (talk) 10:18, 10 October 2011 (UTC)

Lots of studies - but they are of using high concentrations of H2O2 at elevated temperatures. Anecdotal for the 3% stuff. Collect (talk) 13:05, 10 October 2011 (UTC)

This is medical advice. See a doctor or pharmacist.μηδείς (talk) 06:50, 11 October 2011 (UTC)

It is not medical advice. If it was, then telling an OP that colloidal silver is antibacterial, is also medical advice. Plasmic Physics (talk) 08:43, 11 October 2011 (UTC)

This is definitely not medical advice, but general information about hydrogen peroxide and ringworm spores. Doesn't even say it's in vivo for that matter! If you want to see that boundary crossed, see #Push-ups and the "funny bone" nerve... Wnt (talk) 19:39, 11 October 2011 (UTC)

Timing of natural death

What makes a species have a typical life-span? I know that telomeres limits the number of years that humans can live, but are they present in any living creature? And are there other mechanisms to guarantee that a living being will die? Quest09 (talk) 10:24, 10 October 2011 (UTC)

We have an article on ageing in which some theories about the ageing process are explained. For the biology aspect of the question: Telomere actally talks about animal telomeres at some point. Generally speaking: If it has chromosomes (but not a Nucleoid) then it probably has telomeres. --Abracus (talk) 11:15, 10 October 2011 (UTC)

The relationship of the Hayflick limit to aging and death is still not very clear btw. It's also only part of the different "wear and tear" and "programmed death" theories and combinations thereof on the causes of aging (in this case DNA damage).

And yes, excluding gradual senescence and death by predation, diseases, etc. in organisms with negligible senescence, there are other mechanisms that ensure death. Semelparous organisms, for example, like octopuses and most salmon, die because they become completely consumed in ensuring reproductive success in a single event. The rapid senescence and death that follows is hormonal, the body actually tells itself to stop living (phenoptosis). In some species the body of the mother becomes the first meal of the offspring. In Stegodyphus lineatus, for example, the mother actually willingly lets herself be killed for food by her spiderlings. Also see Parent–offspring conflict.

Others die due to mechanical reasons. Weddell seals will eventually die when they lose their teeth, because they can't anymore maintain the breathing holes in Antarctic ice needed for access to water for food, and the surface for air and rest. Grazing mammals will also assuredly die when their teeth are eventually all worn out. Mayflies (which are also semelparous) will die because they do not have the means to feed themselves as adults (aphagy), etc.

In addition to Abracus' link, also see Evolution of ageing and this excellent site: http://www.senescence.info/ .-- Obsidi♠n Soul 13:47, 10 October 2011 (UTC)

Aging is caused by the fact that sexual reproduction is better at ensuring survival of the genes which produce bodies than is any attempt at immortality. μηδείς (talk) 20:53, 11 October 2011 (UTC)

Animal sadness

Apart from humans do other animals experience sadness. --86.45.146.152 (talk) 14:49, 10 October 2011 (UTC)

Yes, Jaak Panksepp has done a great deal of research on this topic. In animals sadness is most commonly referred to as separation distress (we ought to have an article about it) -- Panksepp calls it PANIC but that is widely felt to be a bad choice of terminology. There is also an animal emotion that you might call "despair", known as learned helplessness -- animals that experience bad things repeatedly without any way of controlling them eventually stop struggling and become apathetic. Learned helplessness is thought by many psychologists to be the animal version of human depression. There is a lot more to say about this topic -- Panksepp's textbook Affective Neuroscience covers it in depth. Looie496 (talk) 15:22, 10 October 2011 (UTC)

We do, its on separation anxiety in dogs. CS Miller (talk) 19:55, 10 October 2011 (UTC)

See Animal emotion for an overview. Richard Avery (talk) 15:27, 10 October 2011 (UTC)

(e/c) Also see Animal psychopathology#Depression and Stereotypy#In animals which also discuss anhedonia in animals subjected to stressful conditions, the equivalent of human despair.-- Obsidi♠n Soul 15:29, 10 October 2011 (UTC)

See elephant graveyard and elephant intelligence. Apparently elephants tend to die in places where they remember finding food and water easily--going there when they cannot forage in other places. Elephants are believed to recognize each other by running their trunk tips over each others' teeth. When an elephant dies, its teeth remain. Elephants have been observed spending time repetitively visiting elephant graveyards where they run their trunks over teeth and gently run their footpads over the bones. I think the proper interpretation of this is obvious. μηδείς (talk) 06:49, 11 October 2011 (UTC)

According to our article on the elephant graveyard, they are legendary. Googlemeister (talk) 13:18, 11 October 2011 (UTC)

No, they are not. Or, at least, the existence of a legend does not prove falsehood. Wikipedia itself is not a source, and elephant bone graveyards have been filmed and Elephants have been shown caressing the teeth and bones of the dead with their trunks and footpads. I assume this was broadcast on the American PBS show Nature or Nova. I'll see if I can find a ref for you. Quite a fascinating subject. μηδείς (talk) 20:57, 11 October 2011 (UTC)

Looking on YouTube I think the video of the elephants caressing the bones of their dead is either in the PBS Nature episode Unforgettable Elephants or Echo: An Elephant to Remember. I don't have the time to track down and watch these epsiodes to find the clip, though. μηδείς (talk) 21:03, 11 October 2011 (UTC)

Having slept on it I may also be thinking of an animal documentary which began with a dead chimp and its troop which then showed the elephant graveyard in a later scene. μηδείς (talk) 17:55, 12 October 2011 (UTC)

How do bats avoid bees and wasps?

Do bats eat bees? If not, how do they avoid they avoid them at night? Because bats come out at sunset and bees return to the hive at sunset, do bats perform culling of bee colonies? 69.171.160.57 (talk) 16:00, 10 October 2011 (UTC)

Bees return to the hive well before bats go out feeding. There are bats that are up during the day, but they eat fruit. Unless the bee is huge and looks like a big lemon, the daytime bats won't have any interest in it. -- kainaw™ 16:18, 10 October 2011 (UTC)

They both compete for nectar. I can't imagine an animal with the intelligence of a mouse wouldn't be able to figure out how to bite the head off a bee without getting stung, and then steal its nectar. 69.171.160.57 (talk) 16:45, 10 October 2011 (UTC)

That seems like an awful lot of work for not very much nectar. Anyway, this guy (best source of this I could find) says it's unlikely, mostly for the reasons given above. --Mr.98 (talk) 16:57, 10 October 2011 (UTC)

And no, they do not compete for nectar. There's a wide range of specifically nocturnal blooming flowers for nectarivorous bats (which are most emphatically not insectivorous, though they may be frugivorous esp. in Old World megabats) and moths alike. Plants that actually rely on them, rather than hymenopterans, for pollination.-- Obsidi♠n Soul 17:14, 10 October 2011 (UTC)

Oops. Strike that. It seems that nectar-feeding phyllostomid microbats do eat insects on the side. -- Obsidi♠n Soul 17:23, 10 October 2011 (UTC)

Hm... and megabats as well. Interesting. Though theirs is more opportunistic as they do not possess echolocation (with the exception of Rousettus aegyptiacus) and thus can't snatch insects from midair like microbats do. When they do eat insects though, it's for the protein, not for the nectar.

Also I'm wondering why a lot of sources say megabats are "all diurnal". The vast majority aren't. Out here flying foxes (which are unmistakably huge bats with characteristic slow wingbeats) do not come out until twilight which makes them crepuscular.-- Obsidi♠n Soul 17:46, 10 October 2011 (UTC)

Setting aside the relative rarity of nocturnal bees and wasps that might sting a bat, there is evidence that some bats are able to distinguish between different insects based on their wing beat frequency. Perhaps their target selection is good enough to avoid certain insects. See the theory and the practice. Impressive as that is, oddly on several occasions bats have crashed into me as I've walked through my garden at night. It's quite a complicated space and they have to patrol using complicated looping flight paths but it's almost as if they don't bother to update the large, slow moving objects in their model of a space very often. I guess tree trunks rarely move. Sean.hoyland - talk 18:09, 10 October 2011 (UTC)

I found a paper with percentages of insects found in bat diets. It seems they do eat bees and wasps. There's also an anecdote here of a small bat that attempted to catch a tarantula hawk (genus Pepsis, large diurnal wasps about ~2in), and the squabble that ensued.-- Obsidi♠n Soul 19:34, 10 October 2011 (UTC)

About satellite communication

What is the amplifier used in satellite communication. — Preceding unsigned comment added by 117.231.103.93 (talk) 16:19, 10 October 2011 (UTC)

An operational amplifier. 67.6.175.132 (talk) 23:34, 10 October 2011 (UTC)

The atmospheric radio window dictates that certain microwave bands are best-suited for satellite communications. You can start by reading about microwave communication. I've seen satellite-communication amplifiers that are "MMIC" (pronounced "mimics" - monolithic microwave integrated circuits), ASICs that contain multiple stages - a low-noise front-end amplifier, a gain stage or power amplifier, and a signal conditioner, digital decoder, demodulator, or other circuit elements.

Unique to satellite communication amplification is the need for incredibly high gain (because of incredibly low signal-levels), so there is a huge reliance on very low noise amplifiers. This often means that the first amp is not an op-amp - but a single BJT transistor. Your application may vary. Nimur (talk) 17:02, 11 October 2011 (UTC)

If you are purchasing equipment, the receive side is often done with a Low noise block-downconverter or low noise amplifier if you do not want to convert to an intermediate frequency. The transmit side is done with a BUC or Block upconverter. An output amplifier may be included, or you may need a separate high power amplifier. Graeme Bartlett (talk) 01:14, 12 October 2011 (UTC)

Push-ups and the "funny bone" nerve

So I'm curious, what action could cause the funny bone nerve to get pinched while one is doing push-ups? I notice sometimes that when I am doing push-ups, I feel a slight pinching sensation on the nerve (or sometimes a bit closer to the area above the left side of the end my forearm's bone (I forget its name)). So what is the action during a push-up that would cause this? Sir William Matthew Flinders Petrie | ^{Say Shalom!} 12 Tishrei 5772 16:41, 10 October 2011 (UTC)

Please see Ulnar nerve entrapment. 67.6.175.132 (talk) 23:37, 10 October 2011 (UTC)

Oy vey, this will be fun to tell my doctor about.... Sir William Matthew Flinders Petrie | ^{Say Shalom!} 13 Tishrei 5772 00:05, 11 October 2011 (UTC)

Please note that Wikipedia does not give medical advice, and while that may be one thing that can cause the nerve to get pinched, we have no idea that is true in your case. There could be other explanations, whether more mild or more serious, and you shouldn't rely on this one reference to decide whether or when to get treatment. Wnt (talk) 19:41, 11 October 2011 (UTC)

I am well aware of that. I was asking what such an action is (if anything), not what to do about it (which would be medical advice). During my next doctor's exam I would ask my doctor (by which I mean my general practitioner) about my elbow and give the description of the feeling, and, being the smart Jewish grandmother she is, she would either confirm or deny that it is this ulnar business; and then recommend a course of action based on her own knowledge of the human body. I wouldn't take any real course of action based on RD:S; I like my arm, tyvm. :p Sir William Matthew Flinders Petrie | ^{Say Shalom!} 13 Tishrei 5772 23:59, 11 October 2011 (UTC)

Drunkeness

Obviously humans get drunk on ethanol and from my personal observations, other mammals such as dogs and pigs do as well, but I was wondering if other animals had similar effects? Specifically, I am interested in flying animals, birds and insects, but would also like to know about fish and amphibians. Obviously they have different physiology, but perhaps the effects of ethanol are applicable to a very large range of creatures? Googlemeister (talk) 19:37, 10 October 2011 (UTC)

When I lived in southern California, there was a problem one summer with birds getting drunk off fermented berries along the highway and flying into buildings. So, that implies that birds get drunk. -- kainaw™ 19:52, 10 October 2011 (UTC)

Googling "birds drunk fermented berries" turns up a lot of information on the topic. -- kainaw™ 19:55, 10 October 2011 (UTC)

It seems to have been happening only a couple of weeks ago in Darwin. [2] "A species of parrot ... is on its annual drunken bender."  Card Zero  (talk) 06:14, 11 October 2011 (UTC)

I don't know if they get drunk first but a 1% ethanol solution by mass is enough to kill fish and crustaceans within 24 hours. Dragons flight (talk) 20:03, 10 October 2011 (UTC)

I would think that in creatures with less complicated digestive systems the amount that would get them drunk and the amount that would kill them would be about the same. I certainly wouldn't recommend trying to get a turtle or an ant drunk. Beeblebrox (talk) 20:27, 10 October 2011 (UTC)

Sap-feeding beetles actually love ethanol as it is a primary indicator that resin in trees are ripe for feeding. Beer in pans are commonly used as baits when collecting them. It seems fruit flies can also inhale alcohol vapor as food and can definitely get wasted. LOL. So can bees. Tropical fruit eating bats, however, seem to have evolved alcohol tolerance as a necessity, as a large part of their diet may include fermenting fruits.-- Obsidi♠n Soul 21:38, 10 October 2011 (UTC)

MythBusters tested whether vodka could be used as an insecticide on bees. It didn't work: the bees survived, but flew in a very erratic manner as if they were drunk. (Episode 44 in the 2006 season.) — Michael J 14:38, 11 October 2011 (UTC)

My remembrance of the theory from my organismic physiology class (late last century) is that drunkenness is caused by the effect of ethanol on cell membrane conductivity. That would imply a similar effect on all higher animals with neurons. μηδείς (talk) 21:16, 11 October 2011 (UTC)

Etymology of gestures, difference between intented and unintended gestures, and animals

Woman making the loser gesture

The international symbol of love

Is there some kind of Etymology research for gestures? Like: are there contemporary gestures of which the original -literal- meaning is lost but which would be easy to grasp for people in the Middle Ages? For instance, the gesture for loser is today clearly related to the letter L as is Air quotes to actual quotes. Maybe in 500 years or so, everyone forgot about that original meaning but is still using these gestures in a (possibly changed) meaning. Nod (gesture) has some unsourced explanation (babies nodding when they want milk), and shrugging had a (doubted and removed) explanation.

Slightly related, is there an "official" difference between gestures like "I'm sad", "I'm angry" or "I'm thinking really hard about this" which can be used on purpose but are expressed unintended as well by 4 year-olds when they are sad or angry, and on the other hand the "cultural gestures" one has to learn (like nodding)?

Last question, do animals have these "cultural gestures"? Has someone ever tried to learn a chimp to strike his belly to signal hunger? (instead of pushing the "Hunger" button) Joepnl (talk) 20:02, 10 October 2011 (UTC)

Don't know of any comprehensive research, but the origin of flipping the bird is discussed in the article. Turns out it has quite a long history. Beeblebrox (talk) 20:07, 10 October 2011 (UTC)

Animals communicate with gestures. Most don't have hands and use their body. There are thousands of examples of animal gestures from mating gestures to "get the hell away" gestures. -- kainaw™ 20:10, 10 October 2011 (UTC)

See Gesture#Neurology as well. Beeblebrox (talk) 20:11, 10 October 2011 (UTC)

Some animals can learn very complicated gestures. See e.g. Koko, who has been taught over 1,000 arbitrary gestures (which happen to be American Sign Language, but to Koko they are arbitrary). See also Great ape language. --Mr.98 (talk) 20:15, 10 October 2011 (UTC)

@Beeblebrox, Flipping the bird makes me wonder what it has to do with a bird, but that is precisely the kind of etymology I wanted, and I wonder if there's more like it. Thanks. @Kainaw I know animals use gestures, but I wonder if there are examples of groups of gorillas that have a sign for "Watch out for the crocodile" that other groups don't know. Koko proves that learning them works, but are gorillas also teaching them? The "non-cultural" gestures like "get the hell away" are hard wired evolutionary gestures I think. A peacock probably doesn't know he's making a gesture when he's raising his tail. (I know of a gesture like it that a lot of males along many different species don't need to learn) Joepnl (talk) 20:45, 10 October 2011 (UTC)

As a sidebar, isn't that woman in the picture giving the sign backwards? Falconus^{p t c} 21:21, 10 October 2011 (UTC)

Only a loser does it that way - OR, someone taking a picture in the mirror. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:09, 10 October 2011 (UTC)

I would rather describe Koko's gestures as signs, if we are going to distinguish between natural animal gestures and learned symbolic signs. In any case, Monty Roberts' use of gestures in "horse whispering", (by which he tames even problematic unbroken horses in minutes) such as using a raised hand as an implicit threat or responding to a horses' lip smacking as a request for sympathy is impressive enough to have made me weep to see it. μηδείς (talk) 06:41, 11 October 2011 (UTC)

Woodpecker facts I've been told - true or false?

Things that I've heard people say about woodpeckers - true or false?

1. If a woodpecker didn't shut its eyes when drilling, its eyeballs would fall out?

2. If a woodpecker's tail feathers are removed, it knocks itself unconscious as soon as it tries to drill (because it can't brace itself against the wood properly)?

3. Woodpeckers more than a couple of years old suffer from near-constant headaches and neck pain?

Some of these sound possible, but I've had a look at the woodpecker article, but these points are not specifically addressed. Thanks. --95.150.167.67 (talk) 20:20, 10 October 2011 (UTC)

2 seems to be true somewhat. The tailfeathers are used as support. Removing them probably won't affect their drilling ability though and won't knock them unconscious, but it would certainly have a large effect on their ability to climb trees. Wrynecks do not have stiff tailfeathers, but can still drill on vertical tree trunks by clinging to them with their legs. 1 is true. The eyes are fit particularly snugly to prevent trauma during drilling. The nictating membranes ("eyelids") are slid shut over the eyes just before impact and helps protect them from flying debris as well as restrain them somewhat. The brains are also fit snugly, small, located above the bill, and protected by shock-absorbing mechanisms in the jaw, which in turn makes 3 false. But then again, woodpeckers can't exactly come up to you and tell you they've got a headache. :P -- Obsidi♠n Soul 21:15, 10 October 2011 (UTC)

I asked one about various myths, and all he had to say was, "Ha-ha-ha-HAAA-ha!" ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:04, 10 October 2011 (UTC)

Dude. You taught him that laugh. And at least he's not teeing puttytats.-- Obsidi♠n Soul 22:27, 10 October 2011 (UTC)

Maybe you can infer by their movements that they suffer from neck pains, but how could someone test if woodpeckers suffer from headaches? — Preceding unsigned comment added by 88.11.244.183 (talk) 08:03, 11 October 2011 (UTC)

Just observe female woopeckers, if they don't want to couple, then what else could it be? Wikiweek (talk) 08:08, 11 October 2011 (UTC)

In the Tom and Jerry cartoon “Hatch up your troubles”, the woodpecker kid sometimes keeps his eyes open when drilling (but closes them more often). His or her eyeballs never fall out. – b_jonas 12:20, 13 October 2011 (UTC)

Drop impact absorption

So I'm not sure I'm phrasing this right, but I hope you guys will get the right idea about it. I am wondering, I have purchased both an Otterbox Defender for a BlackBerry Bold 9900 and a Commuter type for a 9700. Now these guys are built differently in which layer is where. The 9700 has the silicone skin against the phone and the hard plastic on top of that. The 9900 one is reversed with the hard plastic on the inside and the silicone skin on the outside (forget about the hard plastic holster and the fact that the whole thing together is a tank). So here is my question. Which design is better for absorbing the energy from an impact? Silicone inside and plastic outside or plastic inside and silicone outside? The plastic is some kind of Polycarbonate btw, but that doesn't mean much to me (by which I mean I don't much about it). Sir William Matthew Flinders Petrie | ^{Say Shalom!} 12 Tishrei 5772 20:29, 10 October 2011 (UTC)

It is impossible to answer this question without details of the structural composition of each design. 67.6.168.177 (talk) 22:01, 10 October 2011 (UTC)

I just said that the hard one was made of polycarbonate and the soft of silicone, so you know their composition. :p Of course, I guess I could link the specs so you can see their dimensions and such. Defender and Commuter Technical specs are at the bottom. However, I am asking which way absorbs better generally speaking? Hard over soft or soft over hard? Sir William Matthew Flinders Petrie | ^{Say Shalom!} 12 Tishrei 5772 23:21, 10 October 2011 (UTC)

Sorry, those are the same link. But without detailed blueprints of the phones and the cases both, I am not going to be able to give you a good answer, and neither is anyone else. These kinds of designs are almost always perfected by potentially destructive actual use testing (throwing them against the floor) so even if you gave us all the blueprints and we had the time to run them in simulators, the answer might still be wrong. 67.6.175.132 (talk) 23:51, 10 October 2011 (UTC)

(edit conflict)Well, I'm not sure how readily available blueprints for either are I'm afraid. Sir William Matthew Flinders Petrie | ^{Say Shalom!} 12 Tishrei 5772 23:58, 10 October 2011 (UTC)

I would think the soft material on the outside would work better, because otherwise the hard material may fracture when it hits the floor (or the floor may dent or crack). Perhaps a soft-hard-soft arrangement might be even better. StuRat (talk) 23:55, 10 October 2011 (UTC)

Depends on how thick they make it. I mean the Defender is pretty damn big already and very thick. Sir William Matthew Flinders Petrie | ^{Say Shalom!} 12 Tishrei 5772 23:58, 10 October 2011 (UTC)

Thicker and harder isn't always better (well, in some cases it is :-) ). Time to pull out an ancient Chinese proverb: "In the gentle breeze, the willow bends, while the mighty oak stands firm. In the powerful wind, the willow bends even more, and thus survives, while the mighty oak stands firm until it breaks. So, which is the stronger, then, the willow or the mighty oak ?" StuRat (talk) 00:07, 11 October 2011 (UTC)

Yes, all other things being equal, placing padding on the outside instead of the inside will change the damage the assembly will do to what it is dropped on at the expense of easier abrasion, and the advantage of less likely case cracking. 67.6.175.132 (talk) 02:31, 11 October 2011 (UTC)

time travel

first of all, i dont have any deep knowledge about physics. Im just wondering, if relativity says going faster that light is going backwards in time, and nothing can go faster than light, that just means the theory is saying that we cannot go back in time, is this right? if its right, then why do we still believe in time travel? — Preceding unsigned comment added by 203.112.82.1 (talk) 22:13, 10 October 2011 (UTC)

I'm not sure scientists actually "believe" in it. Fiction writers certainly do, as it makes for entertaining stories. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:18, 10 October 2011 (UTC)

I think at best scientists might "acknowledge that we're not entirely confident it's impossible." That's a long way from "believe". I'm not aware of any scientist who honestly thinks time travel might ever be a practical thing we could actually do. APL (talk) 06:22, 11 October 2011 (UTC)

Apparently one is hopeful. http://www.youtube.com/watch?v=oRWwI61so5Q ScienceApe (talk) 22:15, 11 October 2011 (UTC)

Scientists don't currently believe that going back in time is possible given our current understanding of physics. Going forward in time, even at different rates, is allowable (and actually achievable). As for why the idea exists outside of science, it is because it is an interesting idea, and allows for the creation of interesting plots, paradoxes, and other Cool Things™. But that's got nothing to do with whether the physics is real or not. --Mr.98 (talk) 22:37, 10 October 2011 (UTC)

i guess my question really is, does theory of relativity implies that going back in time is impossible?

Time travel says "Some theories, most notably special and general relativity, suggest that suitable geometries of spacetime, or specific types of motion in space, might allow time travel into the past". It's still one of the unsolved problems in physics. Clarityfiend (talk) 22:55, 10 October 2011 (UTC)

actually achievable*?wow, can you tell me more about it. — Preceding unsigned comment added by 203.112.82.128 (talk) 22:59, 10 October 2011 (UTC)

If you have magical powers to create any spacetime you want, then it is certainly true that there are solutions to general relativity that involve things appearing to travel into the past. However, it is unclear if there are any such solutions that are actually achievable given that one is starting with a nearly flat spacetime such as the one we live in. You tend to run into problems that need infinite energy, negative mass, or other things unknown to science. So while someone with Godlike powers might be able to open a bridge from the future to the past (e.g. a type of wormhole), it is unclear if any physically achievable configuration of mass or energy would allow that to actually happen in our universe. And the logical difficulties with causality violation seem so severe, that many people argue that it must be impossible to travel into the past. Dragons flight (talk) 23:08, 10 October 2011 (UTC)

I would go further than that and say that opening a wormhole to the past would change the past, which means that it's not really the past, just some kind of copy of what had been the past here in the present. So it would be like making a copy of what happened, and storing it in a transporter buffer and then materializing it and telling everyone, "hey look, it's the past!" The past itself would not change. It's like saying a historical reenactment is the real thing. A complete waste of time and effort for the non-fiction side of the aisle. 67.6.175.132 (talk) 23:43, 10 October 2011 (UTC)

67.6.175.132, is anything in your answer based on anything scientific? Or is it just based on television shows and amateur philosophy? APL (talk) 06:23, 11 October 2011 (UTC)

It's the "logical difficulties with causality violation" to which Dragons Flight referred. Anything, even a spacetime wormhole, which can change the past means, by definition, that what it is changing is not the past, but a strangely connected part of the present. 67.6.175.132 (talk) 20:21, 11 October 2011 (UTC)

If a particle in your reference frame is travelling faster than the speed of light, there is another reference frame, which relative to your initial frame moves at a velocity less than the speed of light, in which the particle travels backwards in time. Thus the one has two frames (that of the observer and that of the particle) in which time travels in opposite directions. You can put whatever you want in these frames, you can put New York in one and Jules Verne in the other, in which case he is travelling back in time. This is not some kind of "crack pot" science, and no scientist with an understanding of relativity would deny that superluminal travel entails time travel, this does not require any weird metrics or gravitational effects like wormholes, as it is a special relativistic effect, and so is valid for perfectly flat spacetime. The caveat that saves causality is that superluminal travel is not permitted, nothing can achieve it, and so the above scenario never arises.

Short answer, the objections about time travel to the past above are correct. But, long answer, if someone were to say that making three right turns is the same as making a left turn, but that no car can make three right turns, so, it is impossible to go left, would be incorrect. It could be logically possible to make one simple left turn even if no imaginable car could make three right turns in a row. That being said, no, you cannot travel backwards in time by any means, ultralight speed or wormholes. μηδείς (talk) 06:26, 11 October 2011 (UTC)

But general relativity on its own allows time travel - see our article on closed timelike curves. To rule out time travel you have to add some additional ingredient such as Hawking's chronology protection conjecture. Gandalf61 (talk) 10:23, 12 October 2011 (UTC)

Or causality, which is already a part of the foundations of general relativity so it's best not to separate the two. Does it help to think that infinite energy would be necessary? Dualus (talk) 17:48, 12 October 2011 (UTC)