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February 1

what's the issue with horsemeat?

I don't get what the issue is with horsemeat being found in burgers. I used to be a strict vegan, but have had massive health problems that I started focusing on, and I basically eat a lot of meat now. I don't see how a horse is any worse than the modern factory farm meat in burgers - in fact if the source is like stables, aren't the horses a lot better take care of? I mean, culturally I would understand if it were dog or cat or rat or racoon/skunk or whatever, but there's no unpleasant cultural associations with horses nor are they dirty or anything...

so, what's the big deal about horse meat being found in burgers? is it dangerous or unsavory or anything else? 178.48.114.143 (talk) 04:30, 1 February 2013 (UTC)

Horses are cute and useful. --Jayron32 04:35, 1 February 2013 (UTC)

Here is a link to an editorial that discusses it. It has plenty of further links within. It is cultural, though. Horsemeat is available in plenty of places. I myself once ate Horse Sashimi in a local restaurant in Vancouver. Bland, I must confess. Maybe if it wasn't raw...

As for Jayron's reply, from what I gather from my link above and the links in it, he about sums it up. Mingmingla (talk) 04:39, 1 February 2013 (UTC)

(ecx2) I think the general objection to the consumption of horses is similar to that usually raised against eating cats, dogs, and other animals commonly thought of as household pets (in the US, anyway). While there isn't necessarily a meaningful objective difference that makes cows any more deserving of slaughter than any other mammal, there is a difference in the way people perceive the animals. To put it simply, people tend to bond with horses more often and more deeply than they do with cows. That's not to say that there isn't the occasional person who has an emotional bond with a cow, but it is certainly rarer than the horse/rider relationship. Just about every young girl in the Anglosphere has at one point wanted to own a pony. The same cannot be said about cows.

Beyond that, and extending outside the sphere of people who have ever been within fifty paces of a horse, is the cultural issue. Essentially globally, every person grows up with the idea that certain animals are eaten, while others are work animals or merely exist in the wild. Domesticated horses are almost always worth more as work animals or transportation than they are as food; it just isn't cost-effective, generally speaking, to raise horses for food when they could be plowing a field of performing other farm work for a significantly longer duration. While this isn't much of an issue in the industrialized world, it was for a long time, and the cultural idea of horses as "animals we don't eat" likely grew out of this distinction. Now we just have to wait for someone to pony up some references. (I'm sorry...) Evanh2008 ^{(talk|contribs)} 04:43, 1 February 2013 (UTC)

(COI declaration - I'm vegetarian.) There is also the issue that the horsemeat in question was from an unknown source, and as such quite probably never passed as fit for human consumption. AndyTheGrump (talk) 04:46, 1 February 2013 (UTC)

That's a factor, and correlating with earlier comments, horses are considered useful, so when they get old and no longer useful, they might be sent to the glue factory or whatever, with their meat typically directed towards the pet-food makers. So, to humans, their meat might be considered unsavory for various reasons. I'm not sure I'd be keen on eating meat from a steer that was close to dying from old age, either. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:12, 1 February 2013 (UTC)

Rabbit#As_food_and_clothing. I think in the USA rabbits are considered cute pets and nobody eats them? But they are so tasty, and their meat is so healthy because it's fat free. European doctors recommend eating rabbit meat. --Enric Naval (talk) 05:39, 1 February 2013 (UTC)

In the U.S., rabbits aren't usually "supermarket" meat sources, but they are certainly not unknown as meat sources. I've eaten rabbit in the U.S., I had hasenpfeffer in a Chicago restaurant once, and I know of butchers here in Raleigh, NC that carry rabbit. So, it certainly exists, unlike horsemeat, which I have never seen sold commercially in the U.S. I'm sure you could get it somewhere, but I've never seen it. --Jayron32 05:58, 1 February 2013 (UTC)

Try in specialized food fairs. Here in Spain I find several small artisan shops that sell hams and paté made of deer and wild boar (boars are typical of the zone, both meats are considered a rarity and capricious), and there is always one selling horse ham. If horse slaughtering is forbidden in the US, then all horse meat will have to be imported. No local small shops will be able to manufacture it locally, and it will be more difficult to find it. --Enric Naval (talk) 09:25, 1 February 2013 (UTC)

Neither venison nor boar is particularly rare in the U.S. They're both very common game meats; anyone who has ANY friends at all that hunt have been subject to about 1000 different venison dishes. Deer are hunted in just about any part of the U.S., boar where they are plentiful including Florida and Texas. --Jayron32 14:01, 1 February 2013 (UTC)

About that editorial: It's possible that the "purists" think steak tartare should be made from horse meat, and it's true that steak tartare is called filet americain in Belgium, but I can assure readers that "filet americain" does not contain horse meat. Ssscienccce (talk) 12:24, 1 February 2013 (UTC)

My brother encountered filet americain in a village on the French-Belgian border about 20 years ago. We'd never heard of it, and expected it to be a beefburger. He couldn't finish it. Years later, I was in Sweden, eating some smorgås with friends, and I remarked 'this beef's very sweet', only to be told 'that's not beef, it's horse'. It was delicious (unlike the filet americain) but I was still a little shocked, as Brits really don't eat horse. I'm now a vegetarian, and my brother nearly so. I'm not sure quite why people are more averse, in general, to eating horses than eating cows, as city-dwellers who almost never see either animal alive. There's a folk-theory about the sacredness of horses to the ancient Celts, but I'm not sure it's well-founded. AlexTiefling (talk) 13:11, 1 February 2013 (UTC)

The main issue is actually that the label at the front and the ingredients at the back are supposed to be accurate. It doesn't matter if it is healthy or not, you must only put in the food what is written in the ingredients. This only enables people to choose what they want to eat. If supermarkets start to break this rule, then how can you trust the halal sausages? How can you trust that the vegetarian burger is really vegetarian? How can you trust that their nut-free or gluten-free products really as they say? It is a wider question of trust in your provider. --Lgriot (talk) 10:17, 1 February 2013 (UTC)

The news talks about "very small trace levels" of horse DNA; Anyone more details about the exact amount? I'm wondering how many different DNA samples (how many cows) would be present in a typical burger. Ssscienccce (talk) 13:27, 1 February 2013 (UTC)

Actually the biggest problem probably was that one of them was estimated to have 29% horse. (From what I heard, for most of the others there was only trace amounts that could arise from processing with the same equipment.) Nil Einne (talk) 13:39, 1 February 2013 (UTC)

The right to know what you're eating is one factor, as others have discussed above. A second is, as AndyTheGrump says, whether the horseflesh is fit for human consumption; it's fair to say if a meat supplier can't accurately tell you what species his meat is (and some of the affected burgers were also contaminated with pork) it's reasonable to have doubts about his control and knowledge of his supply chain from a food safety perspective. BBC Radio 4 had a programme last week (it may have been File on Four) about the world horse meat trade. It said that much of the consumption was in Belgium, France, Italy, and to a lesser extent Germany. There are a lot of horses produced in the US and Canada, for sporting purposes, but these countries have a very low consumption of horse meat. So when sport horses are retired, many are exported (by means of a series of intermediaries) to Europe (with slaughter and freezing done in Mexico). The concern is that racehorses are often treated with drugs like the anti-inflamatory phenylbutazone; doing this renders the horse's meat unfit for human consumption (phenylbutazone causes aplastic anaemia, and may be carcinogenic, in humans). So a racehorse treated with phenylbutazone ("bute") should never be introduced into the human food system, and instead should only be sold for dog and cat food. But as horsemeat for human consumption is much more valuable than for petfood, there's a risk that one of those middlemen will alter the paperwork and declare the horse wasn't treated with bute. This AP report says none of the burgers detected in Ireland showed evidence of bute, but given that the contamination may have been going on for a year or more, the suppliers really can't honestly say they're confident where their horsemeat came from or what's in it. -- Finlay McWalterჷTalk 13:53, 1 February 2013 (UTC)

I find myself skeptical of this explanation. Phenylbutazone's article says that there is insufficient evidence of carcinogenicity at effective doses in humans, let alone as a minor food contaminant, and I would expect the same of the anemia (after all, it was used for some time as a human drug). There is just a tremendous pseudo-religious intolerance toward all sorts of alternate food sources in the U.S., as surely as there is to the clothing of other cultures. Wnt (talk) 15:18, 3 February 2013 (UTC)

Gravity waves caused by a relativistic object

Let's say you have an object like an asteroid that is the size of Texas. But let's say this asteroid is moving at a relativistic velocity (very close to the speed of light). If it passes by earth, would the gravity waves be larger than if the asteroid were moving at a "normal" speed? If this is correct, then the gravity of the asteroid should be a factor of its rest mass plus its relative velocity? But if you were standing on the asteroid, the gravity should only be a factor of its rest mass, since relative velocity is zero. So doesn't this suggest that gravity also has a relative factor? ScienceApe (talk) 06:28, 1 February 2013 (UTC)

The gravitational field about any object is dependent not only on its mass, but also on its linear and angular velocity. However, it is not as simple as applying a gamma factor, as the field about a moving object is not uniform. I am not competent in general relativity, so that's all I can give you. Someguy1221 (talk) 06:34, 1 February 2013 (UTC)

I think it's similar to the electromagnetic field of a moving charge. The electric (resp. gravitational) field lines look like a Lorentz-contracted version of the usual field lines, so the field is stronger perpendicular to the motion by a factor of gamma. The magnetic (resp. gravitomagnetic) field looks like the magnetic field of a current-carrying wire except that it falls off in front of and behind the charge. Like the electric field it doesn't lag the charge, contrary to what you might expect. -- BenRG (talk) 19:02, 1 February 2013 (UTC)

I'm not very sure about what I wrote above. There may be an extra factor of gamma in the GR case. -- BenRG (talk) 19:34, 1 February 2013 (UTC)

Also, an asteroid moving at constant speed doesn't produce gravitational waves. They must be accelerated in order to produce them. Note that gravity waves are an entirely different thing. Dauto (talk) 19:19, 1 February 2013 (UTC)

Coffee and smell

I've heard on various occasions down the years that coffee grounds/granules absorb [bad] smells. The effect is supposedly more than just a nice smell overlaying any bad smells. Is this just an old wives' tale? --Dweller (talk) 09:34, 1 February 2013 (UTC)

The idea seems plausible, ground coffee can be used to make activated carbon, but even without activation ground coffee has a large surface area that could adsorb chemicals. Surface area is still several orders of magnitude smaller, but activated carbon used in industrial processes has to adsorb much larger quantities of gas. Ssscienccce (talk) 12:56, 1 February 2013 (UTC)

Here is a discussion of this on the Straight Dope discussion board.

Here is Heloise's advice.

Here are some actual tests done by real scientists. Alas, they did some extra processing (Add zinc chloride, baked it at 800 degree Celsius / 1,472 degrees Fahrenheit) which sounds a lot like making charcoal.

--Guy Macon (talk) 13:18, 1 February 2013 (UTC)

Armour and Antiarmour IV

I′m sorry because I′m writing my contributes seperated from each other because I don′t know how to edit a page but relating to what we were talking about from yesterday I conclude that tanks are necessary for offensive operations , antitank weapons are -mainly- defensive weapons , tanks armour is still being upgraded , tanks will remian the main weapon for ground forces. — Preceding unsigned comment added by Tank Designer (talk • contribs) 13:47, 1 February 2013 (UTC)

To edit a previous question, find it on the page and click the "[edit]" link to the right of the header. I would suggest the following revisions to your conclusions:

• For the first, tanks remain a useful option for offensive operations. They are not necessary, as can be easily demonstrated via any modern offensive that didn't use them. Depending on the operation, they may even be a hindrance.
• For the second, only if you mean strictly man-portable anti-tank weapons. Vehicular (tanks) and airborne (attack helicopters) anti-tank weapons absolutely have offensive capabilities to match their defensive ones. I'd still question "mainly" in the infantry case -- mostly for a discussion of "mainly intended for" vs "mainly used for".
• For the third, yes. Note also that a major area of research is active anti-missile defense (i.e. shooting down the anti-tank missile before it reaches the tank). Does that really constitute "armor"? I don't know, but it certainly plays into the discussion of whether tanks remain viable on the battlefield into the future.
• For the last, tanks probably aren't vanishing in the near future, but that doesn't guarantee that they will be "the main weapon". As noted in prior discussions, tanks haven't played a primary role in Afghanistan over the past 10 years. — Lomn 16:12, 1 February 2013 (UTC)

Weight of motor

what is the weight of a Starboard crane hydraulic motor — Preceding unsigned comment added by Chibuikeone (talk • contribs) 14:04, 1 February 2013 (UTC)

(I've given this question its own section and title ) SemanticMantis (talk) 15:44, 1 February 2013 (UTC)

Can you tell us the make or model of the crane? The type or class of boat? Otherwise, I don't think we have enough information to give you an answer. SemanticMantis (talk) 15:49, 1 February 2013 (UTC)

Sound, density and bulk modulus in the upper atmosphere

Hi. This problem has intrigued me since a recent physics lecture. I have always assumed that sound travels faster in the lower atmosphere, slower in the upper atmosphere, faster in water, and faster still in solid objects. However, as I recently learned, a medium's volume density is inversely proportional to the speed of sound in the medium, while the Bulk modulus, which is higher for incompressible fluids, is positively correlational to the sound speed. This confused me: what would happen if the pressure was so low that the molecules were too far spaced apart for sound to transmit quickly? I was told that the theory and the model breaks down. What happens when it rains? And now, I just have one more question:

At what milibar height in the atmosphere does sound transmit the fastest, if it is not at the surface, prior to the molecules being spaced too far apart to transmit sound effectively? My first guess would probably be somewhere near the mesosphere or tropopause. Thanks. ~AH1 ^(discuss!) 17:19, 1 February 2013 (UTC)

At very low particle density in gasses, you start to run into the issue of low signal to noise ratio and the best explanations of the limits of sound are best understood from the point of view of information theory more than anything else. Essentially, the medium doesn't have enough information carriers (particles) to effectively preserve the signal (sound) over that of the background noise (random motions of the particles). As the mean free path of particles goes up, the number of collisions goes down, and thus the ability to transmit sound reliably also goes down. This is something kinda-sorta like shot noise as it applies to light transmission, except that particle models of sound energy only work well in condensed matter (like solids and liquids, see phonon). Gases, because of their very different organization, need to be understood differently. --Jayron32 17:26, 1 February 2013 (UTC)

If I understand that correctly, though, it means that there is no actual limit. To get any desired arbitary signal to noise ration, one merely has to employ a sound emitter or micrphone diaphram of sufficient area. That is, the harder the vacuum, the bigger the transducer area required. It is analogous to the use of radio vacuum tubes in low noise amplification - one can achieve any desired signal to noise ratio (which is set by electron shot noise) by using a low enough source resistance and a tube with a big enough electron emission area (neglecting certain other practical circuit factors). Wickwack 60.230.221.94 (talk) 03:35, 2 February 2013 (UTC)

True, but all you're doing is using a bigger signal: that's how you conquer the signal-to-noise ratio problem in almost any application. Using a giant transducer gives you a bigger signal cross section, which counteracts the lower particle density. Of course, the relationship quickly becomes impractical, as there comes a point when the size of the transducer becomes a real physical limitation. A speaker coil the size of the earth is kinda hard to drag around. --Jayron32 04:48, 2 February 2013 (UTC)

This might help. It's quite near the stratopause. Dncsky (talk) 18:52, 1 February 2013 (UTC)

SETI

Suppose there is an advanced non-human civilization somewhere in the Milky Way. They have technologies similar to ours and they have the same power of the radio emissions. Like a copy of the present-day Earth with TV-Stations etc, but far far away.

How far away can they be to be still detectable from Earth? (we use only present-day instruments to detect transmissions; they don't use active SETI) --Blacknight87 (talk) 18:22, 1 February 2013 (UTC)

For an earlier discussion which did focus on active SETI, see WP:Reference desk/Archives/Science/2011 December 30#How far away could Seti detect us?. -- ToE 20:35, 1 February 2013 (UTC)

One thing you need to be careful of in such questions is "when is now" ? If this other civilization has our technology now, then, when our signal gets there, it will be years, decades, centuries, or millennia later, so their technology will have advanced. Do you mean to ask about a civilization which has our level of technology, when the signal arrives ? (Or, in the reverse case, a civilization which had our level of technology, when they sent a signal arriving on Earth today.) StuRat (talk) 18:28, 1 February 2013 (UTC)

Like they had our level of technology X years ago and they are exactly X light years from us --Blacknight87 (talk) 18:31, 1 February 2013 (UTC)

From the Fermi paradox article: It should be noted however that even much more sensitive radio telescopes than those currently available on Earth would not be able to detect non-directional radio signals even at a fraction of a light year, so it is questionable whether any such signals could be detected by an extraterrestrial civilization. Don't know if this is true for all signals. Ssscienccce (talk) 19:13, 1 February 2013 (UTC)

Active SETI has used radio telescopes to send directed messages. These will be much stronger, but I can't find details about the strength of the signal. Those radio telescopes have been used as radar to track planets, asteroids and other objects; those radar signals could also be detected, but again, I don't know how far. Ssscienccce (talk) 19:27, 1 February 2013 (UTC)

From [1], the Square Kilometre Array being presently developed (operational circa 2025), will be capable of detecting signals equivalent to airport radar at a distance of 50 light years. Aside from Active SETI, and other directional deep space transmissions, radar systems emit some of the strongest radio signals on Earth, and hence are a much better candidate for a detectable signal than something like a TV broadcast. So, in the not-too-distant future it would appear that we will be capable of detecting a civilization like ours out to 50 light years. Dragons flight (talk) 19:40, 1 February 2013 (UTC)

Related: http://wiki.answers.com/Q/How_many_stars_within_50_light_years_from_earth --Guy Macon (talk) 20:55, 1 February 2013 (UTC)

I think I read that Arecibo Observatory would be able to detect a similar transmitter about 100 light years away. Bubba73 ^{You talkin' to me?} 03:09, 2 February 2013 (UTC)

We need to find some references - I read (admittedly several years ago) that our most sensitive radio telescope would be unable to detect our most powerful radio transmitter at a distance of 4 lightyears (ie at the nearest star system to ours)...which would mean that the answer to our OP's question would be a definite "No". However, I don't recall where I read that...so I'll defer to your suggestion if you can recall where you read it! SteveBaker (talk) 03:16, 2 February 2013 (UTC)

We should be able to calculate it for Arecibo by how strong of a signal it camn transmit and how weak of a signal it can receive. Bubba73 ^{You talkin' to me?} 04:31, 2 February 2013 (UTC)

The range for a hypothetical Arecibo-to-Arecibo communication has been calculated. The most oft-quoted number comes from Frank Drake (widely known as the creator of the eponymous Drake equation) and comes in at about half the width of our galaxy. I can't readily find an online copy of Drake's calculation, but this page uses a similar approach and shows how the number changes with different assumptions. The pessimistic number is closer to 10,000 light years; the optimistic number (which incorporates some relatively minor and readily-available upgrades to Arecibo's equipment) is good for detection across the full width of the galaxy: roughly 100,000 light years.

That said, those numbers are for detection and not for communication. One could confirm the presence of a signal, but not transmit much data; the integration times used in the above calculations fall between 2 and 6 hours, so you're looking at a few bits per day, at best. (The ability to detect a signal improves with the square root of integration time; with a one-second integration time rather than a two-hour (7200-second) integration, the range is reduced by a factor of about 85, and we're down to exchanging data with our neighbors within a hundred or so light years.) TenOfAllTrades(talk) 16:55, 2 February 2013 (UTC)

Thank you, those are interesting details. Bubba73 ^{You talkin' to me?} 17:28, 2 February 2013 (UTC)

Yes, but those numbers are for a highly directional transmitter and a highly directional receiver. I think the statement I heard was in the context of an omnidirectional transmitter and a directional receiver, or vice-versa which is a more likely case for SETI. SteveBaker (talk) 14:02, 4 February 2013 (UTC)

February 2

0 displacement photon

In a wave the particles do not displace. But according to article photon, EM waves have photons and they displace at speed of 3.0 X 108 m/s. I assume that photons do not travel but only show their energy through vibrations like ordinary matter. So only energy is travelling at the speed of 3.0 X 108 m/s. Therefore the whole universe would be filled with photons and they show different energy intensities by their vibrations just like ordinary matter. I think all should consider this. So do photons actually displace? User:G.Kiruthikan —Preceding undated comment added 11:12, 2 February 2013 (UTC)

Yes, photons move. One complexity of quantum mechanics is that subatomic particles sometimes behave as particles (which do move) and sometimes like waves (which only pass through a relatively static medium). When looking at an individual photon, whose position is known, it's usually considered to be a particle. Only when dealing with light in bulk, or photons with unknown positions, do we tend to view light and photons as waves. See double-slit experiment. StuRat (talk) 16:21, 2 February 2013 (UTC)

I think you are confusing the particle-equivalent of a wave with the medium in which the wave vibrates. In the macroscopic world, we do not usually consider that there is a particle-equivalent, so there is only the medium, which does not displace as you say. But in the quantum world, the particle-equivalent (such as a photon) is entirely separate from the medium (such as an electromagnetic field). --ColinFine (talk) 00:04, 6 February 2013 (UTC)

Grapefruit powder

I regularly buy ruby red grapefruit, but find it often has powder/flakes on the skin which mess up my clothes when I peel it. What is this ? Is it pesticide, a wax added to make it shinier, or some natural coating ? StuRat (talk) 03:56, 2 February 2013 (UTC)

It's almost certainly some kind of food-grade wax, which is ubiquitously applied to commercial fruits to keep them looking pretty on the shelves. This google search: [2] turns up plenty of relevant manufacturers thereof. --Jayron32 04:45, 2 February 2013 (UTC)

OK, assuming it's wax, how can I peel a grapefruit without it making a mess ? StuRat (talk) 05:42, 2 February 2013 (UTC)

Wash it in plain water and a soft scrub brush? --Jayron32 05:56, 2 February 2013 (UTC)

There's also simply yeast which is found on the skin of fruit like grapes. You'd have to post a picture. μηδείς (talk) 05:25, 2 February 2013 (UTC)

If it's wax, warm it with your hands so it becomes pliable, not flaking. Not that we can tell. μηδείς (talk) 05:56, 2 February 2013 (UTC)

That doesn't seem to happen. So, if it's wax, it must have a high melting temperature, as it stays hard at body temp. This is in contrast to the wax applied to cucumbers, which leaves me feeling like I've been "slimed". StuRat (talk) 06:01, 2 February 2013 (UTC)

If it isn't wax, I'm inclined to agree with Medies's idea that this is yeast. Yeast is otherwise completely harmless, it's simply everywhere, and it tends to grow and multiply in places where conditions are right; the outer skin of fruits seems a great medium for yeast: the fact that yeast is so abundant on the outer skins of fruits is what makes applications like wine and cider possible. Now, the acidity of citrus should kill the yeast once exposed to the juice, but the skins aren't that acidic, and its like a decent medium to grow yeast. It bears repeating that such yeast is normal, ubiquitous, and harmless, though if it bothers you running it under tap water for a few seconds and a gentle rub with a rag or brush should take care of it. --Jayron32 06:19, 2 February 2013 (UTC)

OK, I'll try rinsing it off with tap water, then. StuRat (talk) 06:50, 2 February 2013 (UTC)

Most fruit, especially ones with wrinkled or textured skins, should be rinsed/washed. Besides stuff like wax and pesticide residue, bacteria such as E. coli can grow and proliferate. I'm not claiming anything special about the fruit - bacteria can grow practically anywhere - it's just that fruit is often eaten raw and industrial washing is... spotty at best. The situation during harvest may also be quite unhygienic. Matt Deres (talk) 21:45, 2 February 2013 (UTC)

I always wash fruit if I eat the skin, like with grapes, but not when I toss the peels out, as in grapefruit. StuRat (talk) 23:40, 4 February 2013 (UTC)

It could be shellac, which won't melt and will flake. In the US the box has to say what the fruits are coated with, so see if the retailer will let you look at the box. Ariel. (talk) 18:57, 3 February 2013 (UTC)

Sounds likely. How do I remove it without making a mess ? StuRat (talk) 16:52, 6 February 2013 (UTC)

Chemistry question

which of the following contains both ionic and covalent bonds? 1. NaOH 2.HOH 3.C H Cl 4.CO 6 5 2 — Preceding unsigned comment added by 37.228.104.230 (talk) 06:23, 2 February 2013 (UTC)

Please do your own homework.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. --Jayron32 06:24, 2 February 2013 (UTC)

Also, what are you trying to list after CO ? The numbers 6 5 2 alone are meaningless to me. StuRat (talk) 06:48, 2 February 2013 (UTC)

Looking at the wikicode, I'm not sure if 652 is supposed to relate to the question. May be some sort of signature or just erroneous typing. Nil Einne (talk) 19:44, 2 February 2013 (UTC)

Well often here on Wikipedia you can find articles on chemical formulae by typing them in. You will find NaOH, HOH perhaps CHCl3 but perhaps your formula is different. CO leads to a disambiguation page, and you would have to pick Carbon monoxide. check your source to see if you have lost digits. (I dont mean toes I mean subscripts as in H₂O. Graeme Bartlett (talk) 09:58, 4 February 2013 (UTC)

Lime burning

Is it possible to make quicklime out of finely powdered calcium carbonate (such as that produced by chemical precipitation)? Or is there a minimum particle size below which it will get blown back out of any existing kiln? I know that a rotary kiln can process fine particles, but how fine is too fine? 24.23.196.85 (talk) 07:22, 2 February 2013 (UTC)

Anybody? 24.23.196.85 (talk) 04:43, 4 February 2013 (UTC)

Well what scale do you want to make it? Do you just want a few grams, a kilo, do you want to make tons or kilotons? Graeme Bartlett (talk) 10:02, 4 February 2013 (UTC)

Industrial scale -- the idea is to use the CaCO3 produced during the regeneration of caustic solution after the latter has been used for extraction of an acidic substance. I'm flowcharting a chemical plant in my spare time, and I want to make it as environmentally clean as possible. 24.23.196.85 (talk) 00:11, 5 February 2013 (UTC)

In quicklime, you'll see that the most common prodction is by thermal decomposition of calcium carbonate, just as you propose. I'm thinking that the key point is whether there is some particle size that is too small to be processed in a rotary kiln. I would think this depends on the design and process settings of the kiln. In principle, there is no minimum size, but once the particles are small enough to be subject to Brownian motion, the process would become impractically slow. If that's the case in your charted plant, you should consider some other way of heating the quicklime, preferably one that doesn't disperse the powder into air.--Wcoole (talk) 21:40, 6 February 2013 (UTC)

Thanks, Wcoole! Does it make a difference if the limestone powder is wet (50-75% moisture content)? Because that's the case for limestone powder obtained by chemical precipitation such as regeneration of caustic solution. 24.23.196.85 (talk) 02:12, 7 February 2013 (UTC)

Why do tortoises live so long?

Why do (some) tortoises live so long relative to other species, with some of them living 150 years or more? Thank you. Futurist110 (talk) 07:31, 2 February 2013 (UTC)

Well, part of it seems to be a slow basal metabolic rate. All things being equal, the slower the metabolic rate, the longer it takes for some types of damage, like oxidation damage to DNA, to accumulate to fatal levels. See free-radical theory of aging. StuRat (talk) 08:04, 2 February 2013 (UTC)

Other factors scientists are researching include DNA Damage Response and Repair Mechanisms.   ~Eric F 74.60.29.141 (talk) 08:10, 2 February 2013 (UTC)

I am tempted to make the wild speculation here that as random deleterious mutations accumulate over pre-reproductive lifespan, just so many mutations must be "excreted" from the genome via natural selection, or else the species would be overwhelmed and lost. It would seem to follow that a species must have either a good DNA repair, a short lifespan, or vigorous selection in order to survive... but this does not mean that the DNA damage would necessarily have to kill the individual, though it could, of course. Wnt (talk) 19:06, 2 February 2013 (UTC)

Because they are stupid and eat grass. μηδείς (talk) 21:45, 2 February 2013 (UTC)

Looking at it the other way, evolution wouldn't give any advantage to turtles who didn't live a long time, in that it takes a long time to harden the shell; any turtle whose natural life span was like a year after their shell had hardened would be at a disadvantage of having gone to so much effort for so little benefit. So the only turtles you'd see after their evolutionary niche had stabilized would be ones who live a very long time. Gzuckier (talk) 23:15, 2 February 2013 (UTC)

That's spurious reasoning; you could make the same argument that all animals should be long-lived. Also, why do you think it takes a long time to harden their shell? Even little turtles have nice hard shells; it hardly takes decades to form. If you don't know anything regarding a question, it would be best not to pretend that you do. There's good (sourced) stuff up above. Matt Deres (talk) 01:42, 3 February 2013 (UTC)

The spurious reasoning would be that they have better DNA repair; you could make the same argument that all animals should be long-lived by evolving the same mechanism. Your extension to other animals would seem to be reasoning from the axiom that turtles don't take longer than a normal reptilian lifetime to form shells, based on observations of little turtles; little turtles don't live that long, you'll note. Whereas, regarding somewhat larger desert tortoises, "Their shells become essentially incompressible (within 2% of complete shell inflexibility under a moderate force of 11.2 gm/mm²) by the age of about 11 years and a size of about 110 mm MCL." [3] (emphasis mine). Prior to my previous answer I had, of course, investigated all the Wikipedia articles on turtles, tortoise, turtle shells, plastrons, carpaces, etc., as well as all that google would deliver in order to bolster my memory of the slow ossification of turtle shells, and found only this source; at the time I didn't feel it directly relevant enough to cite, but I didn't expect the Spanish Inquisition. Gzuckier (talk) 02:48, 3 February 2013 (UTC)

Now if only parrots slowly grew a protective shell....Gzuckier (talk) 07:17, 3 February 2013 (UTC)

Invention v/s Discovery

Invention An invention is a unique or novel device, method, composition or process. It may be an improvement upon a machine or product, or a new process for creating an object or a result. An invention that achieves a completely unique function or result may be a radical breakthrough. Such works are novel and not obvious to others skilled in the same field.

Discovery Discovery is the act of detecting something new, or something "old" that had been unknown. With reference to science and academic disciplines, discovery is the observation of new phenomena, new actions, or new events and providing new reasoning to explain the knowledge gathered through such observations with previously acquired knowledge from abstract thought and everyday experiences. Visual discoveries are often called sightings.

Now question is , We all know that automobile Inventor Ferdinand Verbiest,If a new BMV car come in market then what it called Invention or Discovery. — Preceding unsigned comment added by Sanilblaze (talk • contribs) 09:01, 2 February 2013 (UTC)

It would definitely be called an invention. Maybe if there's some new physical principle involved it could be a called a discovery. but just a car is definitely an invention. 178.48.114.143 (talk) 09:34, 2 February 2013 (UTC)

[edit conflict]

Neither, it would be a replica or an adaptation of his innovation. Note however, the steam "car" designed by Verbiest in 1672 was a toy for Kangxi Emperor of China, and would not scale-up to an operational "auto-mobile" as we know it. It is debatable that Verbiest "invented the automobile".

• Verbiest did not think, either, that he had invented the automobile. In all humility he thought of his machine as "a method of movement" for which "other diverting applications are easily contemplated."

—Witek, jointly publ. by Institut Monumenta Serica, Sankt Augustin ... Ed. by John W. (1994). Ferdinand Verbiest : (1623 - 1688) Jesuit missionary, scientist, engineer and diplomat. Nettetal: Steyler Verl. p. 268. ISBN 3805003285.{{cite book}}: CS1 maint: multiple names: authors list (link)

~E:74.60.29.141 (talk) 10:00, 2 February 2013 (UTC)

Perhaps there is a Platonic realm of new car designs just waiting to be discovered. Gandalf61 (talk) 10:04, 2 February 2013 (UTC)

Perhaps the fact that we can compare the old car to the new car and show it is improved itself implies there is the objecive image of an ideal car somewhere - acceleration tends to infinite, fuel used tends to 0, etc ---- _nonsense ferret 14:20, 2 February 2013 (UTC)

Intuitively, it seems like it should be obvious that DNA sequences and Penrose tilings are discovered, rather than invented, no matter what the patent or copyright offices may say about the matter. The radio spectrum is something to be discovered, even if the particular arrangement of readily available parts in a specific radio is an invention. And the idea of having, say, a "steam powered car" or "gas powered car" or "nuclear powered car" should be something discovered, or simply an obvious combination of words, rather than an invention, though actually making it is an invention. So I would think that the essence of invention is taking specific fallible, real-world components with real world limitations and variances and tolerances and coming up with a way to do something with them, whereas the essence of discovery is to understand some universal standard from the Platonic realm or from the common legacy of the human race (genes, types of minerals, etc.). A person from an alien race on an alien planet should discover the same things we do, but invent different things. The Platonic ideal of a car should be determinable by doing archaeology on planets of many different stars to find common features. But this is all, alas, a question (or hypothesis) rather than an answer; I'm not even sure how to find reliable sources for any of this. (I should note that there's some tension expressed in the "or" above - I cannot exclude discovery of a specific legacy item though, unless we want to say that Columbus invented America. But there's a difference between discovery of America, which aliens could only make by travelling here, human genes that they can only discover with a sample, etc. and discovering fire or powered flight, which they could do at home) Wnt (talk) 18:45, 2 February 2013 (UTC)

SHD distribution on optical high speed networks

hw SHD distribution on optical high speed networks takes? — Preceding unsigned comment added by 223.228.36.112 (talk) 10:18, 2 February 2013 (UTC)

This question cannot be answered as it does not make sense. Presumably SDH is Synchnonous Digital Hierachy, but what is hw? Takes what? Your IP address gelocates to Bengalore India. You need to take care to write sensible and complete English if you want a useful answer. Keit 124.182.26.251 (talk) 15:06, 2 February 2013 (UTC)

I presume hw is how. I don't think takes is really the best word for what the OP is saying, probably instead something like 'works' or 'is used' or 'is done. Nil Einne (talk) 19:40, 2 February 2013 (UTC)

Or write the question in your native language, and we will translate for you. StuRat (talk) 16:13, 2 February 2013 (UTC)

Thanks

Thanks to all those who answered my January 28 question "Why don't the the sunrise and sunset times go the other way at the solstice?" [4] which has now disappeared into the archives. The answers were very informative. Richerman (talk) 12:57, 2 February 2013 (UTC)

You're welcome. StuRat (talk) 16:14, 2 February 2013 (UTC)

Historical election to fellow of RAeS

I am helping a new editor research the biography of Roy Chaplin. Is the process for the election to a fellow of the Royal Aeronautical Society (RAeS) in 1939 documented anywhere? I suspect that one of Chaplin's papers, presented to the RAeS in 1939, was used as part of such an election process. Are fellowship elections to Royal Society's gazetted?

I see a recently example where it was noted in Aviation Week & Space Technology - but that only started in 1947 so not much help sorry. ---- _nonsense ferret 14:24, 2 February 2013 (UTC)

I've also searched the Gazette for you, but the only reference I can find to his name is the OBE. I did find a couple of other newspaper references so I've added those to the article in userspace, hope that helps a little bit ---- _nonsense ferret 14:58, 2 February 2013 (UTC)

There is a reference to "1960 R.H. Chaplin (Fellow)" as a RAeS Silver Medallists [5] which at least seems to show he was already a fellow, not sure if that helps ---- _nonsense ferret 15:52, 2 February 2013 (UTC)

I drew a blank too in the gazette. I'm not even sure whether fellowship awardselections are gazetted. Your RAeS source does narrow down the time-frame of Chaplin's fellowship election to between 1939 and 1960 and additionally confirms his 1960 silver medal award, thank you. Thank you too for the additional further reading --Senra (talk) 16:13, 2 February 2013 (UTC)

Ground state and vacuum state

Are these synonyms? If not, what is the difference? The articles aren't clear on the point. FT2 ^{(Talk | email)} 18:32, 2 February 2013 (UTC)

No. The vacuum state is the ground state of a quantum field. Every quantum system has a ground state (its lowest-energy state), but only a field has a vacuum state. Looie496 (talk) 18:41, 2 February 2013 (UTC)

Concise, thank you! Can you elaborate a bit and (perhaps equally concisely) clarify the significance of the term "quantum system" (as opposed to quantum field/fields)? Thanks FT2 ^{(Talk | email)} 20:15, 2 February 2013 (UTC)

A quantum system is any system that obeys quantum behavior (Specifically, it obeys quantum commutation rules for the system coordinates and their canonical momenta). A quantum field is a quantum system with infinite (In fact uncountably infinite) degrees of freedom - that's what the word field mean. The simplest fields - scalar fields - have one degree of freedom for each point in spacetime. Note that spacetime has uncountably infinite points. That's in opposition to particle quantum systems (AKA first quantization) which have finite number of degrees of freedom - three space coordinates for each particle (Or countably infinite in case you have infinite particles). Dauto (talk) 01:26, 3 February 2013 (UTC)

February 3

Gravity in a bounded universe

The divergence of the gravitational field is equal to the mass density, which is non-negative everywhere and positive in some places. The net divergence in a bounded system must be zero. Doesn't this mean that the universe is unbounded, and thus the curvature must be non-positive? For that matter, even if it is, wouldn't an approximately even mass distribution result in an unbounded gravitational field?

My best guess is that the mass density of a vacuum is negative. Is this correct? — DanielLC 05:44, 3 February 2013 (UTC)

Your first statement is only correct within Newtonian gravity which is not applicable to the universe as a whole. Dauto (talk) 15:37, 3 February 2013 (UTC)

You are right that the mass density of vacuum is negative (in sense that it produces repulsion instead of attraction), while the energy density is positive. Ruslik_Zero 19:06, 3 February 2013 (UTC)

What does it mean for energy density to be positive? If you change the potential energy of every state under quantum physics, this does absolutely nothing. I've been told you need general relativity to find any sort of energy density of the vacuum. — DanielLC 23:21, 4 February 2013 (UTC)

while we're on the subject of turtle evolution

We've all seen the videos of the little turtle hatchlings crawling toward the sea as fast as they can while sea birds etc feast on them (also noted in our turtle article); why wouldn't evolution push them all to the point where they lay their eggs like 2 feet above high tide line? Particularly when I notice the aforesaid turtle article notes that turtle eggs kept moist do better than those kept drier? Gzuckier (talk) 06:49, 3 February 2013 (UTC)

Unless I'm missing something here, you have pretty much answered your own question. Above high tide line - less moist. At high tide line just moist enough. Richard Avery (talk) 08:00, 3 February 2013 (UTC)

This article suggests that predation is a likely controlling factor with the optimum nest position being close but not too close to the water's edge, I presume that by widening the strip within which nests may be located, the predator's job is made more difficult. Mikenorton (talk) 08:10, 3 February 2013 (UTC)

Also, predation can help eliminate defective genes, by removing the least fit individuals. StuRat (talk) 08:16, 3 February 2013 (UTC)

Another factor to consider is that nests which are placed too close to the high tide line run the risk of being drowned, and as noted in the "cape" episode of David Attenborough's Africa series, should the nest be flooded before the eggs hatch, they won't survive. douts (talk) 14:15, 3 February 2013 (UTC)

Light bulbs. halogen --> LED

I have 81 50-watt halogen downlighters GU10 ES50 which link to 240v - 12v transformers. Can I get something which will provide the same amount of light in one LED bulb? Kittybrewster ☎ 10:45, 3 February 2013 (UTC)

Assuming you mean to replace EACH 50 W halogen light with one LED fitting, the answer is yes. Have a look at this: http://www.siliconchip.com.au/Issue/2013/February/Replace+Your+Halogen+Down-lights+With+LEDs. Ratbone 124.182.26.251 (talk) 10:59, 3 February 2013 (UTC)

Yes. Good. Warm white, daylight or pure white? 2w 3w 4w or 5w? Is there a reference for these lights at a UK supplier?Do they need a 12w LED Driver Transformer for MR16-MR11-G4 LED Light Bulb by Long Life Lamp Company? Kittybrewster ☎ 15:19, 3 February 2013 (UTC)

I've replaced some GU10 12V halogens with LEDs. They run on 12V AC (IIRC, they have a built-in rectifier). For some reason they don't have the halogen-equivalent wattage marked. However, LEDs about about 3 times as efficient as halogens, so I'd go for about 15W. The lamps are marked as non-dimmable; if you want to dim them you might need to buy a ballast. CS Miller (talk) 20:02, 3 February 2013 (UTC)

The best answer is 'may be'. Presuming you don't mean to replace anything in the fitting, replacing 12V halogens with LED equivalents can be problematic. You can find many complaints from a simple search, some people recommend just replacing them with main voltage ones. The problem is in the transformer, the electronic transformers (switched mode power supply) commonly used may be designed for 50W bulbs and may not like the far lower voltage, some may not work at all. Even if they do work, you sometimes get flickering due to an interaction between the switch mode power supply on the bulb and the switch mode power supply in the fitting. The output from the SMPS is most likely not a simple 50 or 60 hz AC since it doesn't matter to the halogens. More reliable manufacturers often have long lists of transformer compatibility charts for their lights. In the unlikely event your bulb uses a simple transformer, I would guess you shouldn't have problems.

However although not commonly discussed, there is an advantage to the 12V namely safety. In fact I read about [6] [7] which shows even someone like Philips can screw up their design. I personally chose GX5.3 12V as opposed to GU10 240V despite the issues because I prefer cool white bulbs (at least 5000K and preferably higher) and it's not that easy to find high CCT bulbs from reliable manufacturer with a high CRI (even when it comes to the raw LEDs they're far rarer then low CCT high CRI). However I did encounter flickering from some of the bulbs I purchased from AliExpress using Sharp COBs. I believe the ones that flicker for me use a boost drive as the LED forward voltage is above 12V (some of the LED dies are series) which highlights I guess another unfortunate fact, a number of COBs and LED arrays do have a forward voltage above 12V because they're targeted at the line voltage market where it's an advantage since the buck driver doesn't have to reduce the supply so much. One intermediate option between going main voltage is to keep the fitting but replacing the transformer with one designed for LEDs (or better both LEDs and halogens) source from a reliable manufacturer. Of course you could replace the whole fitting with an LED one, I didn't do that here because what's available seems rather poor and limited, even before taking in to account my preferences but things may be better in the UK.

The other consideration is the design of your fitting. If the bulbs are enclosed or recessed in the wall, you're far more likely to have a problem since LEDs really don't like to get hot. For the same reason, 50W halogen equivalent is difficult for a bulb that sized. Some of the Philips GX5.3s (and I think GU10) even have a fan. (In my case I purposely overlighted the area so it doesn't matter if they aren't so bright.) This also depends on your requirements. If you want a high CRI low CCT light you'll need a more powerful bulb since both high CRI and low CCT generally means a lower luminous efficacy. Even when it comes to similar CRI and CCT, LEDs are still rapidly evolving so it depends significantly on the LED used. (As well of course on the efficiency of the driver.)

Nil Einne (talk) 05:31, 4 February 2013 (UTC)

P.S. From a quick search, one more problem you may have is I don't think GU10 12Vs are particularly common. AFAIK, GU10s are usually main voltage and GX5.3 are used for 12V in the MR16 world. Given the similarity, for Chinese manufacturers from AliEpxress you may be able to get them to make some GU10 12Vs easily if you're buying a decent quantity perhaps 10-20. For well known brands, you'll just have to use what's available. Nil Einne (talk) 05:51, 4 February 2013 (UTC)

Male vs female pain

I heard that females are more tolerant to pain than men, because men have more pain receptors. It's linked to the Y chromosome. Is this true?Dbjorck (talk) 08:30, 3 February 2013 (UTC) Copied from Talk:Nociception#Male vs female pain 10:54, 3 February 2013 (UTC)

In Sexual dimorphism it says generally females feel pain more than males. I believe I read somewhere this applies even to babies so it is not something that is just learnt. This makes sense really, males fight more and pain that distracted would be a disadvantage. Dmcq (talk) 14:07, 3 February 2013 (UTC)

This is like asking "is the sky brown?" Common sense should be more than enough to tell you it's blatantly false, and that women are far more sensitive to pain. In case you don't believe common sense, here is an article that quotes a scientific paper. Here is an article from Scientific American. "The reason for this is not known, Fillingim said. Past research suggests a number of factors contribute to perceptions of pain level, including hormones, genetics and psychological factors, which may vary between men and women, Fillingim said. It's also possible the pain systems work differently in men and women, or women experience more severe forms of disease than men, he said." --140.180.247.198 (talk) 17:56, 3 February 2013 (UTC)

Googling "number of pain receptors" returns some pages, amongst a lot of junk, that indicate both sexes have about the same number of pain receptors per unit area of skin. Since men are bigger and have more skin area than women, they have more pain receptors. However, this does not mean more sensitivity, nor less.

The study reported in Scientific American is deeply flawed, as reading the attached reader comments shows. To measure something, whether it is magnitude of pain, volts in an electric circuit, or the weight of a parcel, you need a measurement system that has appropiate resolution, and calibration. They measured by asking patients to rate their pain on a numerical scale, 0 = no pain, to 10 = worst pain imaginable. That's plenty of resolution, probably too much, but there is no calibration. Who is to say whether I can imagine a pain more severe than you? Perhaps I fell off a ladder, breaking my hip. Perhaps you were very sick with an intestinal blockage. Perhaps we both never before had any pain worst than childhood accidents. Perhaps I have a more vivid imagination. Perhaps I only think I do. A better question might be "What is the severity of your pain, 0 = no pain, 1 = I have pain, but I am happy to ignore it, 2 = the pain constantly intrudes on my consciousness, 3 = I cannot think or function at all with this level of pain 4 = I want to die" Since the brain has evolved over a very long period of time to prioritize what gets presented to consciousness with a well defined structure, this would give at least some calibration.

It should also be noted that we have more than one system for sensing pain. There is a specific nerve network ending in pain receptors in the skin. There is a quite separate system of nerves ending in pressure sensors in the digestive system. The brain interprets excess pressure as pain. It may well be that men are more sensitive than women for skin pain, and women more sensitive to gut pain. Or vice versa. Or some other combination. By not recording and accounting for this, the study repoted in Scientific American is futher flawed.

Not only is the preception of pain severity, and the degree which an individual reports it (two different issues confounded in the SA study) culturally influenced ("real men don't cry"), it depends on state of mind. It is well known that humans will put up with almost anything if they have the right state of mind, and/or they can see a light at the end of the tunnel. In World War 1, for example, General Monash was able to inspire troops to put up with hardships unimaginable to folk that have not served in a battle. After my wife had an operation, the nurse came around and asked her to rate her pain. On being told it was as bad as anything, the nurse gave her a narcotic and valium. A little later, my wife asked for more. But the nurse sized her up and said she could have a half dose of narcotic and no valium. My wife protested, saying the pain was again bad. The nurse replied, "You should expect some pain, you are obviously well aware of your surroundings now. If I keep giving you valium, you will become addicted." Whereupon my wife decided the pain was not so bad after all, and talked to me brightly about all the flowers and phone calls she had received from her work mates. — Preceding unsigned comment added by 124.178.53.46 (talk) 01:36, 4 February 2013 (UTC)

Wickwack 121.215.57.3 (talk) 01:03, 4 February 2013 (UTC)

Re calibration: Remembering my psych grad school daze, if people are provided with defined end points to a scale, they can be relied upon to scale stimuli very nicely (usually on a log scale) and repeatably, whereas in the absence of such defined end points the reported intensity wanders all over the scale between different subjects, or the same subject various times. Of course, we weren't paining people (that would be a creepy experiment; "Now, call this pain 10 out of 10" and then do ???), but the finding was so universal that I'd be really surprised if pain receptors were any different. As for the other factor, yeah, everybody who is familiar with dogs or kids has probably seen them smack into a wall full tilt or something when playing and laugh it off, while when they're looking for pity the teeniest scratch or bruise will cause copious agony. Gzuckier (talk) 02:49, 4 February 2013 (UTC)

True. I probably should have said the SA study had poor calibration at the top end, rather than saying there was no calibration. The top end calibration was poor because it requires imagining the most severe pain, and that depends on experience. Wickwack 60.228.245.239 (talk) 03:08, 4 February 2013 (UTC)

I admit the Scientific American article was not the greatest example. Nevertheless, there is abundant evidence that men have a greater pain tolerance than women, and none at all for the opposite viewpoint. This literature review, for example, describes studies that use brain imaging to measure human pain response. Differences in pain tolerance have been unambiguously found in both humans and animals. In humans, these differences appear in subjective questionnaires like the SA study, behavioral tests such as Lowery et al, and PET brain scans such as Paulson et al. In animals, the differences appear in behavioral observations and brain measurements, like measurements of stress-induced analgesia. By "differences", I mean that males have unambiguously higher pain tolerance than females, and not the other way round. This other review article claims that the results of brain imaging studies are mixed, but is nevertheless unambiguous in its conclusion: "Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances." Of course all of these studies, just like all of science, are limited or flawed in some way. Even so, they're much more trustworthy than WP:OR based on one anecdote about WWI and another anecdote about somebody's wife. --140.180.247.198 (talk) 02:58, 4 February 2013 (UTC)

The study quoted in our Pain threshold article is Sex Differences and Incentive Effects on Perceptual and Cardiovascular Responses to Cold Pressor Pain by Daniel Lowery, MA, Roger B. Fillingim, PhD and Rex A. Wright, PhD. Alansplodge (talk) 19:23, 4 February 2013 (UTC)

D'oh! Already linked above - sorry 140.180! Alansplodge (talk) 19:25, 4 February 2013 (UTC)

Wasn't there also some surprising finding, in the last few years, that certain painkillers were ineffective for women while being very effective for men? I recall it being taken as further evidence that the pain pathways and natural painkilling mechanisms were different in men and women. It also was taken as a cautionary tale of the dangers of narrow samples being used in drug trials and taken as representative of the wider population. Ring any bells for anyone? 86.163.209.18 (talk) 22:06, 4 February 2013 (UTC)

Black holes: Why the most complex objects in the universe?

Andrew Strominger (and others) state that event horizons are governed by a strikingly simple set of quantum laws which implythat black holes are at once the simplest and most complex objects in the physical universe. I understand the first part, as they are defined by three parameters only - mass, electrical charge and angular momentum (however, this is derived from general relativity, not from quantum laws, isn't it?) But why are they the most complex objects? I understand it has to do with Black hole thermodynamics and the Black hole information paradox, but still fail to explain, not the least in confusion how the concepts entropy, information and complexity interact in this case. --KnightMove (talk) 13:09, 3 February 2013 (UTC)

Utter speculation on my part, but I'm guessing that if you tried to map the event horizon, you might end up with some ridiculously, fractally wiggly line, just like the Mandelbrot set, another surprisingly-complicated system with a surprisingly simple definition. —Steve Summit (talk) 13:41, 3 February 2013 (UTC)

It's probably because black holes have the largest physically possible entropy for an object their size (Bekenstein bound). -- BenRG (talk) 06:15, 4 February 2013 (UTC)

This article exactly demonstrates my confusion: This article uses the terms entropy and information as straight proportional almost-synonyms, while they are generally regarded as almost-opposites and an increase in entropy means a decrease in information. This leads to the next ??? when entropy is supposed to increase in the universe, while information supposedly cannot decrease... --KnightMove (talk) 10:53, 4 February 2013 (UTC)

Yes, the word information is used inconsistently. It means "the logarithm of the number of equiprobable states", but they may be talking about different states in different circumstances. If they're counting indistinguishable microstates, it's the same as entropy. If they're counting phase space volume, it's conserved. If they're counting distinguishable macrostates weighted by the number of indistinguishable microstates in each one, it's the sort of information you're thinking of. -- BenRG (talk) 17:16, 4 February 2013 (UTC)

antimatter

Is there any likelihood that there is a way to change matter to antimatter using a relatively small amount of energy so that you can use matter-antimatter interaction to gain energy? Bubba73 ^{You talkin' to me?} 14:17, 3 February 2013 (UTC)

What do you think, Bubba? Such a thing would make possible a perpertual motion machine, as no doubt you have realised. Floda 120.145.46.100 (talk) 14:46, 3 February 2013 (UTC)

How would you make a perpetual motion machine with this? What Bubba suggested converts matter into energy, so you would need to continually supply matter (fuel) to keep the machine running. - Lindert (talk) 14:54, 3 February 2013 (UTC)

(ec) No, it would not make a perpetual motion machine possible. What you gain in energy, you lose in annihilated matter and antimatter, via E=mc². There may be other reasons why this is impossible, but neither the first nor the second law of thermodynamics stands in the way. --Stephan Schulz (talk) 14:59, 3 February 2013 (UTC)

Erk! You are right. Floda 121.215.4.176 (talk) 16:13, 3 February 2013 (UTC)

My impression is that a very small black hole is just such a catalyst, but I don't know if that is actually true. Wnt (talk) 15:11, 3 February 2013 (UTC)

A very small black hole might conceptually be able to convert matter to energy efficiently - you feed the matter into the black hole at the same rate that it is dissipated in the form or Hawking radiation. However, this is highly unstable. The smaller the black hole becomes, the faster its rate of evaporation. So you need to feed it more matter to make it cool down. If the math at Hawking radiation holds up, a 200 ton black hole will produce 7 billion gigawatts. You need to feed the mass equivalent of that into the black hole to keep it stable, against that radiation pressure. And the major snag here is that we would need a good theory of quantum gravity - I doubt that general relativity scales down to quantum sizes. --Stephan Schulz (talk) 16:24, 3 February 2013 (UTC)

Well, the problem isn't really so much keeping it stable as getting over that hump to create a synthetic black hole in the first place; after that you can bulk it up until it converts energy at a sedate rate and is less likely to explode suddenly if the computer crashes. And yes, the question of what the smallest possible black hole looks like is of the greatest interest, since it is at once the greatest obstacle and, if it can actually be created, perhaps the greatest opportunity, to do the conversion at that step of creation only, never having a black hole that has any possibility of slipping away and eating the Earth. Wnt (talk) 17:07, 3 February 2013 (UTC)

If one had access to a smallish black hole (I'm not talking a furiously-Hawking-radiating size, necessarily, either, just conveniently smaller than a solar or planetary mass) it would be a dandy source of energy. Throw any old matter that you like into it, and you'll get a significant fraction – typically at least 10%, and possibly upwards of 40% depending on the circumstances – of the mass-equivalent energy radiated back out. (Frictional heating makes infalling matter hot. Like, really hot.) This isn't Hawking radiation, this is just plain old blackbody emission from still-outside-the-event-horizon matter making up the accretion disc. Black hole#Accretion of matter touches on this point. (Science fiction buffs may recognize this concept from Imperial Earth, in which Arthur C. Clarke used small black holes in this way to power interplanetary ships.) TenOfAllTrades(talk) 19:33, 3 February 2013 (UTC)

Guys, you seem to be missing the big picture here: the question is one step away from saying "Can we convert matter into energy according to e=mc^2, using a relatively small amount of energy"? If we do take the "logical" next step in the question (use the antimatter to gain energy), that's all this is equivalent to. In other words, using up matter directly, for its high theoretical energy yield, using relatively little energy. Is such a thing theoretically possible? Is it possible by the means suggested, of turning the matter into antimatter first, using relatively little enrgy? 178.48.114.143 (talk) 15:32, 3 February 2013 (UTC)

Well, that's what I described with the small black hole, but I suppose I should have clarified. If you make a very small black hole, smaller than a primordial black hole, then it will evaporate in a very short time by Hawking radiation. So in theory, if a black hole has only mass, charge, and spin that is, you can cram matter down its gullet (emphasis on the cram, as we're speaking of something the size of a subatomic particle, perhaps) and what comes out may be particle pairs, matter + antimatter, that can annihilate and produce light. But ... I don't know for sure myself, what with all the talk of some kind of conservation? of physical information in the Hawking radiation, whether there could be some sort of 'matter-ness' in the black hole you feed this way after all that would somehow foul the scheme. Wnt (talk) 16:16, 3 February 2013 (UTC)

I was talking to a friend who was wondering about getting energy from matter-antimatter interaction. I asked "where do you get the antimatter?". I said that it takes more energy to make antimatter than you would get out. He wondered if it was possible to convert regular matter to antimatter and use it, with a net gain in energy. I doubt it, but I don't know. Bubba73 ^{You talkin' to me?} 16:39, 3 February 2013 (UTC)

I don't think the question is one step away from saying "Can we convert matter into energy according to e=mc^2, using a relatively small amount of energy" ? The question is much more fundamental. Can you change the sign of the charge of a particle. Sean.hoyland - talk 16:48, 3 February 2013 (UTC)

Nay, it's not changing the charge. For example, if you dump only protons into a mini black hole, it will quickly take on a positive charge (one of the three properties they do have by all accounts) and repel taking up more; when a virtual pair becomes Hawking radiation it will be the negative one that drops in the event horizon and the positive one that goes away, most likely, until the balance of charge is restored. Wnt (talk) 17:03, 3 February 2013 (UTC)

The OP's question is "Is there any likelihood that there is a way to change matter to antimatter" Sean.hoyland - talk 17:08, 3 February 2013 (UTC)

Or "Is there any likelihood that there is a way to change matter to antimatter with using a minimal amount of energy", where minimal amount is << 2mc². ---- CS Miller (talk) 17:24, 3 February 2013 (UTC)

Right. And have it so that we can use it, e.g. not inside a black hole. Bubba73 ^{You talkin' to me?} 17:50, 3 February 2013 (UTC)

Wouldn't rotating matter in the fourth dimension make it into antimatter? μηδείς (talk) 21:24, 3 February 2013 (UTC)

Unless there's some exchange between different elemental particles, that would seem to violate Charge conservation, i.e. if an electron can be 'turned' into a positron through the fourth dimension without involving any positively charged matter, the net electric charge of the universe changes, which shouldn't happen. - Lindert (talk) 23:10, 3 February 2013 (UTC)

But charge alone isn't conserved, isn't it something like charge x mass x velocity that is conserved? You will have to forgive me, as I am totally ignorant here, but I seem to remember something like this. μηδείς (talk) 01:28, 4 February 2013 (UTC)

Charge is conserved, energy is conserved. Neither of these is necessarily violated by changing matter to antimatter, but doing that will violate conservation of baryon number. It's not clear whether conservation of baryon number is a fundamental law or just a general observation. Baryon asymmetry would suggest the latter. Someguy1221 (talk) 01:37, 4 February 2013 (UTC)

In the sense of "a black box that you push matter into, and antimatter (and some waste matter & energy) comes out" - yes, of course we can do that. Inside we'd have a fusion reactor which is converting matter into energy (and a lot of waste product) and something as described in Antimatter#Artificial_production using that energy to create antimatter. If you don't look inside the black box, it does what the OP wants - but the relatively small yield of the process means that you'd be better off just using the fusion reactor to do the work.

More directly, Antimatter#Positrons says that you can fire electrons at a small diameter gold target using a laser and get positrons out the other side - which is doing that conversion - but the amount of energy needed in the laser presumably exceeds the amount of energy you'd get by recombining positrons and electrons - or else I'd have something like that inside my electric car! So no free energy device here!

If there is a way to do this conversion cheaply, we don't know what it is because according to Antimatter#Cost, the current price to create antimatter is between $25 billion per gram (positrons) and $62.5 trillion per gram (antihydrogen). The cost of storing the stuff in any quantity would likely be off the charts!

However, the lower of those two numbers looks promising! One gram of antimatter can produce 2mc² = 18,000,000,000,000,000 Joules of energy. A KWh is 3.6MJ - so our gram of positrons makes 50,000,000,000 KWh. A KWh costs about $0.1 in the USA right now...so that's $5bn worth of electricity for a $25bn outlay...well, OK, nobody's getting rich on this anytime soon - but it's not that inefficient. A 20% efficiency would be economical for (for example) powering a car or an airplane. If you could find a way to reliably contain the stuff (and that's a huge "IF"!), you could easily store all of the energy your car would ever use in a box that might fit conveniently into the glove box and which could be installed into the car when it's manufactured! That kind of energy density would certainly be worth having.

SteveBaker (talk) 13:48, 4 February 2013 (UTC)

Assuming that such antimatter powered cars would have about the same efficiency as today's electric cars, and doing a quick back-of-an-envelope calculation (0.1-0.23 kW.h/km accroding to our article, and assuming a design life of 300,000 km), you would need about 100-200 GJ of energy, which is 25-50 tonnes of TNT. I'm not sure I want to be driving round with the equivalent of a small tactical nuclear weapon in the glove box, so the containment question is, as you say, a huge "IF". Apologies if I have made an order of magnitude error somewhere, I did the calculation rather quickly!

Equisetum (talk | contributions) 17:54, 4 February 2013 (UTC)

Yall might find Neutral particle oscillation interesting - a process by which neutral mesons do indeed (Spontaneously !) convert into their antimatter selves. Dauto (talk) 16:19, 4 February 2013 (UTC)

Basically, if there were any way of converting ordinary matter particles (protons, neutrons and electrons) into their antiparticles with a relatively small amount of energy input, it would happen spontaneously by quantum tunneling, and ordinary matter would decay into photons and neutrinos, and there would be no us. So no. -- BenRG (talk) 17:25, 4 February 2013 (UTC)

Chemistry after nuclear decay/transmutation

In most studies of nuclear decay, the atom's electron shell and what it is bound to is not considered. However, this is what I am interested in.

Consider a molecule of dimethylpropane (neopentane), that has been carefully crafted so that the central carbon is ^{14C, and then others are 12C, i.e. 14C(12CH₃)₄. It is observed until the central atom decays to 14N+, (assuming the electron ejected from the nucleus isn't captured by the shell). Thus we now have 14N+(12CH₃)₄.}

My question is, is one of the methyl groups ejected by the nitrogen, to form N(CH₃)₃, (assuming that this molecule is stable)? CS Miller (talk) 16:40, 3 February 2013 (UTC)

Trimethylamine is a real and stable – though rather stinky – chemical compound. My first thought was that such a compound arising would be unlikely simply because radioactive decay is a relatively energetic process; one might expect the recoil of the newly-formed nitrogen-14 nucleus to rip it loose from any chemical compound to which it was attached. (For reference, the decay energy for carbon-14 is about 156 keV (156,000 eV), whereas typical covalent C-C and C-H bond-dissociation energies are on the order of 4 or 5 eV. While most of the beta decay energy gets carried off with the emitted beta particle and neutrino, some small fraction of it ends up with the N-14 nucleus.)

It turns out, though, that that isn't necessarily the case. Remarkably, carbon-14 decay is gentle enough (barely) that at least some of the expected derived N-14 compound may survive, under at least some circumstances. Way back in 1956, Wolfgang et al. actually did a similar experiment using C-14 labelled ethane (H₃C-CH₃), and found that 47% of the ethane molecules survived 'intact' post-decay to form the anticipated compound, methylamine: H₃C-NH₂. Whether or not this result generalizes well to the decay of neopentane, I wouldn't hazard a guess. TenOfAllTrades(talk) 17:55, 3 February 2013 (UTC)

Thank your for your speedy reply ToaT, unfortunately I don't have access to that paper. I didn't know that some of the decay energy ends up in the atom, rather than the ejected subatomic particles. Neopentane was just used as an example; I could have chosen any organic molecule. Assuming that the recoil doesn't rip the nuclide out of the molecule, am I correct to think, after the decay, the product nuclide will eject an attached group to retain a stable 8 octet?

A follow up question. If the the groups are different (say the 3rd carbon in 3-methylhexane decays), is it possible to predict what will be ejected? CS Miller (talk) 19:28, 3 February 2013 (UTC)

Tetramethylammonium, or even more complex Quaternary ammonium cations, isn't so unstable that it would be likely to fall apart (you probably have bottles of them in your shower and laundry!). It still does have a stable octet, it just also (now) has a charge. DMacks (talk) 21:32, 3 February 2013 (UTC)

Uh, tetramethylammonium is toxic and is not normally used in household detergents. Most household detergents use alkyl sulfonates, which are more effective in this application in any case. 24.23.196.85 (talk) 04:54, 4 February 2013 (UTC)

Quat-ammonium compounds are commonly found in many products for many reasons (obviously less-toxic ones often suffice). I encourage you to read our article about them to see many applications (including subarticles such as shampoo the common polyquaternium class of ingredients among others). The question was about stability vs flying apart: even the tetramethyl article's studies on toxicity are predicated on it being stable enough to study. DMacks (talk) 12:33, 4 February 2013 (UTC)

What is this crinkly wood - and why is it so?

Split wood showing crinkly grain (approximately circumferential split face uppermost, radial split face on right)

The pictured wood is from the UK, is lightweight and easily split in either plane. It is mainly pale yellow with some red streaks and is very crinkly throughout available samples. The wavelength of the crinkles is 6-7mm and their polarization is circumferential to the tree, so that the surface of radial splits is highly corrugated. No bark remains on the sample.

What is it? and why is it so?

Thanks --catslash (talk) 23:24, 3 February 2013 (UTC)

It's hard to say with certainty without knowing more about its source, but it seems to be a form of burlwood. E.g.:[8], from:[9] ~:74.60.29.141 (talk) 00:41, 4 February 2013 (UTC)

Is it perhaps from a Dutch elm diseased tree? Is Crinkley Wood near Crinkley Bottom? See also Noel's House Party --Senra (talk) 04:19, 4 February 2013 (UTC)

No, Dutch Elm disease affects the bark and the structures immediately below, the woody trunk is unaffected, apart from the fact that it becomes part of a dead tree. Elm is notoriously slow to rot, Old London Bridge sat on elm piles for 650 years. I'm old enough to remember trying to burn the damned stuff; "Elmwood burns with a churchyard mould, E’en the very flames are cold..."[10]. Alansplodge (talk) 13:12, 4 February 2013 (UTC)

'Walter' here has a theory about it. I have seen it in mature oak and olive wood. A real nuisance when you're splitting logs. Richard Avery (talk) 08:20, 4 February 2013 (UTC)

I like the "reaction wood" explanation - and (of course) we have an article about that: Reaction wood. SteveBaker (talk) 13:11, 4 February 2013 (UTC)

Perhaps that photo→   would make a good addition to the article (which could also use a citation to the certified arborist @Wavy Wood - Explained) - However, would this be WP:OR or perhaps wp:synthesis?   ~:74.60.29.141 (talk) 17:56, 4 February 2013 (UTC)

February 4

Acupunture for Cerebral Venous Thrombosis

request for medical advice
The following discussion has been closed. Please do not modify it.
Dear Sir, I was diagnosed for Cerebral Venous Thrombosis, bilateral papilloedema, left VI nerve palsy, Neck Supple, Plantar↓. I have been under conventional medication for the past 2 years and there are no signs of reducing my drug dosage. I started having side effects and when I spoke to my Neuro Physician about the side effects. I was told it is to be expected due to drug effects. For a holistic approach for my medical condition, I started taking Acupunture for the past 3 weeks. I feel lot of relief. But I need to know if there is any document on positive relief for CVT. I am unable to locate any document, article on effects of Acupunture treatment for CVT. Can you please guide me on the topic.Marhabha (talk) 06:59, 4 February 2013 (UTC) We cannot give any medical advice. Articles may be at acupuncture and Cerebral venous thrombosis. Graeme Bartlett (talk) 08:32, 4 February 2013 (UTC) Graeme is right; we cannot give medical advice. Talk to your physician again and ask him the specific question you asked here. Typing the name of the medication in the Wikipedia search box may lead you to other relevant Wikipedia pages. --Guy Macon (talk) 10:02, 4 February 2013 (UTC)

freezing insect eggs?

Various sources suggest putting insect prone food (oatmeal, rice, etc.) in the freezer to kill the eggs; but I'm dubious. Does that really kill the eggs, or just keep them from hatching while it's actually in the freezer? Because if it does kill the eggs, why don't they treat the food at the plant before selling it? Gzuckier (talk) 07:34, 4 February 2013 (UTC)

The ability to reliably survive freezing is a rare trait in insects. I think you can be confident the eggs really do die. No clue why they're not so treated before hand if its a real concern. My guesses would be that either some of in the insect contamination is post-shipping, or they are being cheap. Someguy1221 (talk) 07:42, 4 February 2013 (UTC)

This is pure anecdote but you can take what you want from it. I found a superb local baker but unfortunately his flour has flour moth and after a couple of weeks I had some flying out of my bread box. I bought in batches of a dozen loaves, putting most in the deep freezer until needed. This action had no effect on the viability of the eggs, they survived the freezer for up to 3 weeks. I now reheat the loaves in a hot oven for 5 minutes. No moths. Richard Avery (talk) 08:04, 4 February 2013 (UTC)

woah dude, I'd be looking for a different baker myself ---- _nonsense ferret 13:14, 4 February 2013 (UTC)

For good bread I go the extra mile! Richard Avery (talk) 14:07, 4 February 2013 (UTC)

We have our very own baker for that. He may be a bit off your beaten track, Richard. You may have to go the extra 5,000 miles. -- Jack of Oz ^[Talk] 08:07, 5 February 2013 (UTC)

Different insects have different amount of resistance to freezing[11][12] and even different basic strategies.[13] One surprising aspect of this is that many insects are better at surviving freezing if they have experienced winter weather in the previousmonth[14] -- insects generally do not maintain their cold protective systems when their environment remains relatively warm. --Guy Macon (talk) 10:28, 4 February 2013 (UTC)

It is doubtful that the moths came from eggs in the baker's flour; they wouldn't survive the bread baking process (note your 5-minute re-heat). I had this problem until I lined my pantry with "Spanish cedar" (which is neither Spanish nor cedar). ~:74.60.29.141 (talk) 18:17, 4 February 2013 (UTC)

I agree, there is no way the moths came from the baked loaves. They probably simply live in your house and are attracted to the crumbs left over in the bread box. So your experiment of freezing them did not determine anything. If reheating them does anything, you are simply killing eggs that are laid, in your house, on the outside of the loaf. As a practical suggestion buy a pheromone sticky trap made for pantry moths. Ariel. (talk) 18:42, 4 February 2013 (UTC)

It sounds like freezer temperatures should kill any stage of Ephestia kuehniella [15] [16] (99% of eggs in 5 hours). But the other one... would you believe somebody wrote a book about it? But no freeview. Still, [17] says that eggs are the hardiest stage and 99% of them die in 6 hours. Then again, I don't know the species for sure. Wnt (talk) 19:14, 4 February 2013 (UTC)

As it happens I had a detailed conversation with the baker and they are aware of the problem and are embarking on a new pheromone based capture strategy. They flour the baked loaves with unbaked flour and this is the source of the eggs, so there we are - I came to offer some personal advice not seek comments about my eating habits. I'm not complaining, they bake the best bread I've ever eaten. Richard Avery (talk) 19:22, 4 February 2013 (UTC)

Thanks for the encouraging advice; particularly since I could potentially stash stuff outside in winter for a bit.... but anyway, in regard to the tangent re contamination in said baker's place; the reason I asked is because I'm getting so many products contaminated. I did at first think perhaps they were getting contaminated by a domestic infestation, although why certain products would or wouldn't get infested is a question, so I started stashing each item I bought in a tupperware or similar container as soon as it got home, but that didn't improve things, so I assume they're getting imported in the food. Not just the usual stuff you'd expect like flour or rice, but processed stuff like spaghetti, hot cocoa mix, etc. Of course, FDA regulations are always grosser than the layperson expects. Gzuckier (talk) 19:41, 4 February 2013 (UTC)

Why would they flour the baked loaves with unbaked flour? It's normal to use some flour as a release agent, but that flour gets baked. Why add unbaked flour after? Ariel. (talk) 19:54, 4 February 2013 (UTC)

Are you saying that bread, flour, rice, spaghetti and hot cocoa mix all have the same insects even when stored in Tupperware? So what is common to all? Same store? Same warehouse feeding multiple stores? Could it be something weird like always leaving the food on the same rug or in the same auto trunk for a while or maybe all your Tupperware has loose lids? (Not that I believe that any of those could be the common factor, just asking what all the foods have in common) --Guy Macon (talk) 20:26, 4 February 2013 (UTC)

Evolutionary purpose of non-reproductive sex

From the perspective of evolution, the purpose of sexual intercourse is reproduction, and the purpose of reproduction is species continuation. But some species such as bonobos, dolphins and humans have non-reproductive sex. From the perspective of evolutionary biology, what is the purpose of non-reproductive sex? Even from an evolutionary perspective, non-reproductive sex may be harmful to a species as it will create continuous sexual competition and resulting injuries and death. So does it provide any evolutionary benefit? --PlanetEditor (talk) 17:51, 4 February 2013 (UTC)

We have an article Animal sexual behaviour which despite its flaws, goes in to this in a variety of ways. Our article Bonobo#Sexual social behavior also discusses it as specific to bonobos (notably it appears to function somewhat the opposite of what you're suggesting). We have a large number of articles like Human sexuality covering sex among humans and related topics (Concealed ovulation for example may be of interest) although if you're old enough you may have ample knowledge that sex can serve many purposes among humans many of which will have a variety of possible evolutionary benefits. Nil Einne (talk) 18:56, 4 February 2013 (UTC)

Pair bonding - "sex for pleasure" keeps the male close enough to the female to contribute (directly or indirecty) more than just his gametes to raising offspring. Roger (talk) 19:06, 4 February 2013 (UTC)

• It's a fallacy, selectionism, to assume that every aspect of biological organisms has to be seen as serving some evolutionary purpose. μηδείς (talk) 20:30, 4 February 2013 (UTC)

  Gould was a known anti-sociobiology writer. You need to find a neutral source. It is absolutely possible to explain each and every physiological and behavioral feature of a species, including humans, in evolutionary terms. --PlanetEditor (talk) 05:13, 5 February 2013 (UTC)

Absolutely. And if we accept the suggestion that there's competitive advantage in making reproductive sex pleasurable, the pleasure in non-reproductive sex appears to come as a trivial side-effect. AlexTiefling (talk) 22:50, 4 February 2013 (UTC)

Take a look at Why Is Sex Fun?, which gives many evolutionary arguments for why it is so. Shadowjams (talk) 01:05, 5 February 2013 (UTC)

Non-reproductice sex exists because sex conveys an evolutionary advantage, and prevention of non-reproductive sex doesn’t. - Nunh-huh 02:37, 5 February 2013 (UTC)

That's a non-answer, it just restates the question in different terms. What the OP is asking about is what the evolutionary advantage is. --Jayron32 04:56, 5 February 2013 (UTC)

Actually, Nunh-huh's answer is correct if you add the premise that non-reproductive "side effects" arise from successful reproductive ones. If females being attracted to males is a well successful strategy, but it results in certain males also being attracted to other males, it will exist because the first is a very successful strategy and the second doesn't matter. Evolution doesn't care about the homosexuality of the male in that circumstance so long as his mother and sisters are successful. μηδείς (talk) 05:19, 5 February 2013 (UTC)

You could add any number of sentences to Nunh-huh's answer to make it correct. He didn't add any such sentences. What he wrote, however, is neither correct nor incorrect, merely a redundant restatement of what evolution is. --Jayron32 05:30, 5 February 2013 (UTC)

OP, you say that some species have non-reproductive sex, and you mention bonobos, dolphins and humans as examples. I prefer to believe that pretty much all species engage in this behaviour. Can you show me a single species where conception occurs every time they have sex? Or that the participants could care less either way? (other than humans; we seem to be the only species for whom this is an issue) They enjoy getting their rocks off as much as we humans do. -- Jack of Oz ^[Talk] 05:23, 5 February 2013 (UTC)

Evolution isn't trying to weed out those traits that do not contribute to survival and reproduction. Evolution describes how small advantages in survival and reproduction tend to be perpetuated in succeeding generations. Non-contributory traits, as long as they are not too disadvantageous or are merely neutral vis-a-vis survival and reproduction, tend to be perpetuated as well. Bus stop (talk) 05:54, 5 February 2013 (UTC)

One more question. Are only the animals with menstrual cycle exhibit non-reproductive sex? --PlanetEditor (talk) 06:48, 5 February 2013 (UTC)

No. Many types of birds pair up for life, or at least long periods of time, and enjoy sex for bonding purposes. Birds do not menstruate. Wickwack 121.221.92.200 (talk) 06:57, 5 February 2013 (UTC)

Coffee

How many typical styrofoam cups of caffeinated coffee, filled approximately 3/4 of the way, does an average person needs to drink consecutively in order to be killed by caffeine overdose? 140.254.121.34 (talk) 19:28, 4 February 2013 (UTC)

This is perhaps a trick question. Ignoring the size of a "cup" for now, the article caffeine says 80 to 100 cups of coffee have a 50% chance of doing the trick. But if a cup is indeed a cup, then this is 40 pints, 20 quarts, five gallons of water, and water intoxication would probably set in sooner than that. Therefore, you should not be able to die of caffeine overdose because something else would kill you first. :) But ... differences in cup size, and the length of time required to clear water versus caffeine from the system, might undermine that. Funny, I just can't interest myself in doing this math, though I feel like for some reason differences in cup size should normally be more interesting. :)Wnt (talk) 19:41, 4 February 2013 (UTC)

It takes quite a large amount of caffeine to be dangerous. Caffeine can start causing problems once you consume more than 1 gram of the substance and be lethal at 10 grams, so doctors like [Cleveland Clinic cardiac surgeon] Gillinov recommend that people don't consume more than 400 to 500 milligrams a day. For comparison, he said an average cup of tea has about 40 miligrams while a tall cup of Starbucks coffee (12 ounces) has about 260 milligrams of caffeine, though other brands average about 100 milligrams for a regular sized cup.   —Castillo, Michelle (October 24, 2012). "Can you overdose on caffeinated drinks?". CBS News. CBS Interactive, Inc.     ~:74.60.29.141 (talk) 19:53, 4 February 2013 (UTC)

Great! Now you have me craving coffee! Thanks. μηδείς (talk) 20:25, 4 February 2013 (UTC)

Twin fingerprints

Are identical twins born with identical fingerprints, and then the prints diverge later as they grow, or are they born with different fingerprints? RNealK (talk) 22:54, 4 February 2013 (UTC)

Different fingerprints. Uncle Cecil says so. Identical twins are only identical genetically. They will develop in non-identical environments, and as a result will have subtle differences, including fingerprints. This NYT column briefly explains the effect of subtle environmental difference, and itself links to more in depth documents. --Jayron32 23:17, 4 February 2013 (UTC)

Thanks. RNealK (talk) 23:22, 4 February 2013 (UTC)

February 5

Yellow rain

In December 2012 Sri Lankan towns such as Mineragala and Southern provinces experienced Red rain and towns of Polonnaruwa and Kantale experienced Yellow rain. But the article about yellow rain totally differs from this rain. So natural yellow rain should be also included here. Sri Lanka based researches reveal that this colouration of monsoon rains was due to remains of meteorites. So what is the difference between natural and artificial ones? Source:

• [18]
• [19]
• Rupavahini broadcasting (government's official broadcasting channel)

--G.Kiruthikan (talk) 07:06, 5 February 2013 (UTC)

I fixed the dead links above. Sean.hoyland - talk 07:38, 5 February 2013 (UTC)

Both the red rain and the natural form of yellow rain are actually varieties of blood rain, which is caused by large quantities of dust and pollen in the air (the meteor hypothesis, BTW, has been disproved). "Artificial" yellow rain, however (I put it in quotes because its very existence is unproven) is a hypothetical Soviet chemical weapon allegedly used against South Vietnam by the Vietcong in 1975, which may be composed of various mycotoxins, mustard gas, etc. FWiW 24.23.196.85 (talk) 08:53, 5 February 2013 (UTC)

Law of excluded middle, null hypothesis, and disproof of god

Ok so let's say that the statement "god doesn't exist" is the null hypothesis and "god exists" is the alternative hypothesis. So the null hypothesis can not be proven and is the default position, that directly implies that the claim "god doesn't exist" can not be proven. Let's define god as the being that is described in The Book of Genesis. Since this being has been described as creating humans, that is a demonstrable claim that can be falsified. Evolution has falsified creationism, and therefore the god described in The Book of Genesis has been disproven. According to the Law of excluded middle, two contradictory propositions (i.e. where one proposition is the negation of the other) one must be true. Since the alternative hypothesis has been disproven, it stands to reason that the null hypothesis must be true according to the Law of excluded middle. So my question is, can something be true, without it being proven (using this logic)? ScienceApe (talk) 02:00, 5 February 2013 (UTC)

This is the reference desk. Can you rephrase that as a specific request for research help, rather than a long invitation to debate? μηδείς (talk) 02:13, 5 February 2013 (UTC)

A statement can be assumed true, and thus require no proof. This is the essence of the method by which most religious persons justify their convictions. 72.128.82.131 (talk) 02:38, 5 February 2013 (UTC)

Your argument utilizes the strawman argument and is not a proof; and "using this logic" [sic] one can prove anything. ~:74.60.29.141 (talk) 02:44, 5 February 2013 (UTC):~

Or disprove anything. No believer has ever come up with any evidence that would convince a scientist there is a god, and no scientist has ever been able to cause a believer to doubt there is a god. Then there are scientists who teach evolution but privately are strong believers in the God who created the universe ab initio. Work that out. -- Jack of Oz ^[Talk] 02:53, 5 February 2013 (UTC)

Not to mention that God and evolution are not mutually-exclusive. [I didn't mention that] ~:74.60.29.141 (talk) 03:48, 5 February 2013 (UTC):~

The trick here is that you are defining "god" very narrowly here, as being not merely the god of Genesis but a particular interpretation of that god which is one whose work must leave evidence demonstrably contradictory to evolution. So your proof of "god not existing" is equally narrow. You have not, for example, disproved that there could be a God who created the world as in Genesis, but who subsequently covered up his prior work by some miraculous means to leave only evidence of the natural history implied by our current laws of physics; or who did the creation in a parallel universe and copied and refined it in this one; or who did the work in some sort of Platonic realm of archetypes; etc. Wnt (talk) 05:12, 5 February 2013 (UTC)

I am not personally very interested in not the god-vs-no-god debate - at least, not at face value. I feel that this debate has been rehashed by many intelligent people, and many many more unintelligent people, for many centuries, and in many languages. What I am interested in is the Kolmogorov complexity of their debate, and more importantly, the marginal contribution to that complexity of any new individual's argument. I fear that we are reaching a plateau, where the complexity no longer increases, because the exact same arguments for each side are made, over and over and over again, by people who have chosen not to invest the time to read the earlier parts of the "thread." Now, it's a heck of a lot of effort to expect every Tom, Dick, and Harry to start off with Plato and Thomas Aquinas and Sartre; but by golly, if somebody's interested in the subject, then they really ought to invest the time to read all the prior arguments so that we can make forward progress in the discussion, instead of repeating the same string-literal arguments, without adding to the complexity. (And yes, I posit that in five centuries of English, and five decades of digital texts, somebody has written almost exactly the same string of text as your brilliant idea to prove, or disprove, anything). If only there were a free repository of great classic literature, and short encyclopedic summaries to help guide the interested reader through the denser parts of the prose... I bet each person could expend a little effort to ramp up on "prior art," and there would be much less repetition of the elementary tenets of formal logic, theology, and the general theory of human knowledge. And more to the point, we could then process this digital corpus to estimate the Kolmogorov complexity of the god-vs-no-god debate, giving us an upper-bound of the importance of it, as measured in bits-of-entropy. We could then compare that to the bits of entropy in other observed phenomena. Nimur (talk) 05:28, 5 February 2013 (UTC)

This is not a place for religious debates. Why don't we just hat the whole thing? 24.23.196.85 (talk) 05:39, 5 February 2013 (UTC)

Malala, the girl who survived the Taliban's assassination attempt, today called her survival a gift from God. And there's not a soul on earth who can prove her wrong. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:47, 5 February 2013 (UTC)

Being nearly assassinated and surviving? I think I'll pass on gifts from God then thank you very much. Dmcq (talk) 10:30, 5 February 2013 (UTC)

feeling "surreal" or like the world is a fabrication or a simulation

Is this a known symptom of psychosis? This is not a medical question, I just wonder if there are lots of people in society with undiagnosed schizotypal disorders, thanks. 71.207.151.227 (talk) 11:44, 5 February 2013 (UTC)

This is not about the philosophical belief, more like the emotional feeling that people have, i.e. it is a very visceral feeling. 71.207.151.227 (talk) 11:44, 5 February 2013 (UTC)