Wikipedia:Reference desk/Archives/Science/2012 July 29

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July 29

Need a flat metal surface for heat sinking - suggest melting aluminium or solder?

I have a couple of brass candelabras which I'm using in a lighting project. The light will come from high power LEDs inside the candle cups. I need a good thermal connection between the rear of each LED bead (I intend not to use the star-mounted LEDs) and the metal candle cups. In order to obtain a good connection, I need a flat surface in the bottom of each cup. To obtain a flat surface, I was thinking I should melt some metal in the bottom of each cup. Aluminium has a lower melting temperature than brass and may be a possibility. However solder has an even lower melting temperature and may be much easier to work with, although its thermal conductivity is lower. Would solders containing a flux core pose a problem for this application? — Preceding unsigned comment added by 2.97.18.184 (talk) 01:33, 29 July 2012 (UTC)

The thermal conductivity of solders varies quite a bit, with ordinary tin-lead eutectic not very good. See http://www.electronics-cooling.com/2006/08/thermal-conductivity-of-solders/. In contrast, the thermal conductivity of alauminium is about 250 W/m.K (http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html), about 5 times better than ordinary solder. Never-the-less, depending on the cup size and shape, it is probably the case that even tin-lead solder will be good enough. By mathemically modelling the volume of the metal as concentric thin cups of simple half-sphere & cylinder shape you can calculate the therml conductivity from LED to cup outside surface, and you can roughly estimate the heat conduction from cup to air with Pressman's formula: R = 7400 A^-0.7 (R in ^oC/W, A in mm²) You probably won't get a sufficiently flat surface due to surface tension, and depending on what metal the cups are made of, you may have issues with the melt disolving some of the cup material - this can significantly increase surface tension. Surface tension may force you to spot-face machine the surface to get it flat. Flux residue can be dissolved off with citrus-tpe solvents, but if you are going to machine the surface, that will get rid of teh flux as well. Keit121.215.49.33 (talk) 03:40, 29 July 2012 (UTC)

Standard practice is to use thermal paste, which makes the matter of surface machining moot. It isn't adhesive, though, so you'd likely need to use a fastener to attach the LEDs, and you would still need to have two surfaces that are roughly complimentary shapes (i.e. matching concavity/convexity). BigNate37_(T) 03:52, 29 July 2012 (UTC)

+1. I've also seen metal rods of an appropriate diameter soldered as close to the hot component (LEDs) as possible on the lead which you can ground to the fixture, and then soldered to the fixture, and then smothered in thermal ceramic/silicone paste over the solder. 207.224.43.139 (talk) 05:29, 29 July 2012 (UTC)

Note that the usual sorts of thermal paste sold for electronics heatsinking purposes is not at all thermally conductive compared to metals. It's only designed to go as a thin smear between two "mill finish" flat surfaces bolted together. My Radiospares catalog gives thermal conductivities ranging from 1 to 3 W/m.K. Compare that to aluminium (250 W/m.k). Such thermal pastes provide a small benefit because transistor/diode/etc surfaces and heatsink surfaces are normal machined surfaces and not mirror polished - this means that without the paste there is microscopic air gaps btween high spots, and even 1 W/m.k conductivity is orders of magnitude better than air. Using such pastes in other than a thin smear will not do anything useful. Keit120.145.177.174 (talk) 06:41, 29 July 2012 (UTC)

Silicone thermal compound based on aluminum nitride is better than solder at over 100 W/m*K, so you can slather it to protect the solder joint. I don't know if that's typical for heatsink compound. 207.224.43.139 (talk) 07:20, 29 July 2012 (UTC)

Do you know any trade names, product codes, manufacturers, etc, that we can use to to trach down & purchase such wondrous stuff? The link provided for silicon nitride in the Wikipedia article on thermal grease is a dud. Keit120.145.141.39 (talk) 12:09, 29 July 2012 (UTC)

Use a table spoon to melt solder over a gas stove and pour it into the light fitting if the light fitting has a watertight metal form. You may be able to epoxy shut small escape routes for the molten solder in the base of the cups, but do that outdoors for certain because the epoxy will give off even more volatile fumes than the melting solder. (Do it on a BBQ) Use a pedestal fan. Place the fan very close to the work as you are melting and pouring, with the fan facing away from the work and away from you. It will suck away the fumes without disrupting your work. I agree to take full legal responsibility for your head falling off and the city catching fire, so be sure to email this note to your lawyer first. You might also try running a led embedded in putty in the fitting, or silicone sealant, or mixing metal shavings in, Then measure the temperature of the LED after 5 minutes and see which gives the lowest reading. You can ask a local engineering shop or handyman to turn some pieces of aluminium for you and use heatsink grease for the gap. (And always remember, don't solder while naked) Penyulap ☏ 14:42, 29 Jul 2012 (UTC)

Does it matter? LEDs don't produce a lot of heat. That's what makes them so energy efficient compared to incandescent bulbs. Why isn't air cooling sufficient? --Tango (talk) 17:23, 29 July 2012 (UTC)

A few watts a piece if it is the large ones, the ones the requester says they won't use, if it is a simple 5mm or 3mm two lead package, then the power consumption is tiny and no heat sink is required. But as they are mounted flat, it seems to be a package somewhere in between, which makes sense as the small ones can't light up a room really. I think the best thing to do is to hook one up and then enclose it in the same manner it is meant to be in permanently, and measure the final temperature as I said. It's most likely there is enough conductance to keep it cool. But any high brightness led say, over 100mA can get quite hot so long as it is thermally insulated, most of the time it is not, and certainly open air cooling is enough to cool it. Keeping the heat contained is what the enclosure will or won't do. I'd say just give epoxy a go. Penyulap ☏ 17:57, 29 Jul 2012 (UTC)

For a high power LED it does matter. Since the OP isn't even putting it on a star or round heatspreader there's a good chance they will kill probably within seconds to minutes it without a good thermal connection to some heatsinking. This doesn't mean aircooling isn't sufficient, simply that it needs a good thermal connection to a resonably sized heatsink. The LED datasheet should give good info on what is required (every power LED datasheet I've looked at had a section on thermal management). Personally I'm far from convinced the solder idea is sufficient but the OP will need to look in to the requirements themselves. Also the OP hasn't exactly specified what sort of power LED they're referring to and what their target current range is. E.g. the requirements for an XM-L run at 3A (maximum rated) would be quite different from one run at 350mA (or for that matter a XB-D run at 350mA). I suspect the OP isn't considering something like a large LED array, e.g. a Bridgelux BXRA-56C9000-J-00 [1] with a typical forward voltage of 30.4V run at 3.75A (maximum rated) but who knows?

Remember that while LEDs may be fairly efficient they have a much smaller surface area and volume and also do not like to get hot losing efficiency i.e. generating more heat for less light as they get hot (which from the end user POV generally means if the designer knew what they were doing and used a good constant current driver, the LED can get visibly dimmer as it warms up) and also lowering their lifespan possibly quite significantly depending on the running temperature. And their efficiency is also helped by the low amount of non visible light (which doesn't hang around the LED). I've discussed all this in more detail with references in the past if there is still any confusion.

Nil Einne (talk) 10:44, 30 July 2012 (UTC)

Does atrioventricular block benefit the heart of athletes?

Here it is mentioned that athletes can have certain heart conditions that in non-athetes would be considered to be heart diseases:

"First degree atrioventricular block and second degree Möbitz type 1 block occurred more frequently in athletes. Atrioventricular dissociation and Möbitz type II block were not observed in controls but did occur in athletes."

So, does having an atrioventricular block benefit someone who does a lot of endurance training? Count Iblis (talk) 01:52, 29 July 2012 (UTC)

You might wish to look at our atrioventricular block article. I can't imagine that it would be beneficial for the atria and ventricles to lose their usual synchrony, but our article says that in athletes it may be "benign". Looie496 (talk) 04:13, 29 July 2012 (UTC)

Origin of HIV/AIDS

In a recent question on the humanities desk the OP repeated something I've frequently heard before that I have never been able to find a reliable source for, or even a reliable source debunking it, namely; that HIV was first transmitted from simians to humans though sexual contact. I can think of numerous reasons why this is highly unlikely (a human is unlikely to have been the receptive participant, the penetrative participant has a low chance of contracting the virus and this probably isn't something that happens regularly, the apes in question are very strong and not likely to enjoy such treatment, etc.). The scientific consensus as far as I'm aware is that it was people eating bushmeat contaminated with the virus that caused the initial transfer to humans (contracting the virus in this way is also unlikely, though I suppose this happens frequently enough to explain it). Can anyone provide references or links to discussions on this dubious hypothesis? 203.27.72.5 (talk) 01:58, 29 July 2012 (UTC)

Reading History of HIV/AIDS as well the reviews cited in the transfer section don't even mention sexual contact as a possibility. If the article accurately portrays the neutral point of view, then I would say that human-chimp sexual contact as the point of entry of HIV into our species is an extreme minority viewpoint. Someguy1221 (talk) 02:24, 29 July 2012 (UTC)

I'm sure it is an exteme minority viewpoint amongst medical professionals and anyone who has stopped to think about what they're saying, but I keep hearing it or reading it which leads me to believe it is some sort of a relatively common misconception. I'm not going to attempt a google search right now because I'm on a work computer, but I'd think there would be quite a few hits for people restating the hypothesis in forums, etc. I'd like to know where it came from and I'd really like to see where some expert in the field has debunked it. 203.27.72.5 (talk) 03:47, 29 July 2012 (UTC)

Bushmeat#Role in spread of diseases explains the much more likely vector, and [2] is the most recent review you want, citing this specific detailed primary source. Sexual contact between chimps, apes, or monkeys and humans is very rare, with bushmeat being much more common as per that source. 207.224.43.139 (talk) 05:40, 29 July 2012 (UTC)

Thanks, but neither of those mention the hypothesis I'm asking about. There is an (unsourced) mention of the the misconception at Misconceptions_about_HIV/AIDS#Origin_of_AIDS_through_Human-monkey_sexual_intercourse, so if someone finds a source I can add it to that. Apparently one Republican state senator from TN repeated it in an interview. 203.27.72.5 (talk) 09:34, 29 July 2012 (UTC)

The fact is that our data is too limited for the specific means of transmission to be anything other than a guess. However, sexual relations is a quite poor one. Either being bitten by a wild or pet monkey (which would also have a lesion of some kind or to suffer an injury, since saliva is not a viral reservoir), or having contact with a recently slaughtered monkey while having a cut (This could easily be imagined if one is preparing the monkey to be a meal) is much more likely. But if a Tennessee politician thinks he can gain votes in his district by guessing sex, it isn't impossible. There is no reason any authoritative scientific source would discuss it. Bestiality with monkeys in Africa is almost certainly rare or non-existent and other avenues are not anywhere near as implausible.173.15.152.77 (talk) 12:52, 29 July 2012 (UTC)

I'm not sure what you're looking for. It's pretty obvious where the misconception comes from - HIV is sexually transmitted in humans, it is thought to have originated in monkeys, so people put two and two together and get five. I'm sure loads of people have independently come to the same misunderstanding, so you aren't going to be able to find the origins of the misconception. --Tango (talk) 17:49, 29 July 2012 (UTC)

On a related question, if you eat the meat of a human who is infected with HIV, can you contract HIV? ScienceApe (talk) 16:22, 29 July 2012 (UTC)

Contracting HIV by giving oral sex to someone that is infected has an extremely low chance of infection (although it is increased if you have any sores or cut in and round your mouth). Eating infected flesh would presumably be similar. (Note, it being very rare to catch it this way doesn't invalidate the bushmeat hypothesis - as long as there were enough people eating enough infected bushmeat, someone would get infected sooner or later.) I can't find a reliable source for the likelihood of catching HIV from oral sex, but I'm sure I've seen one before. The best I can find is this CDC page saying it is probably less likely than from anal or vaginal sex, but it doesn't give any numbers. --Tango (talk) 17:49, 29 July 2012 (UTC)

I can't help but recall something Frank Zappa said in the early years when the monkey story came out: "So who's been screwing those monkeys?" ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:06, 29 July 2012 (UTC)

Eating is only part of it. The hunting and butchering part is the more dangerous end of the bushmeat trade. Wounds and blood galore.

Anyway I found this source: HIV/AIDS, Health and the Media in China. It closely parallels that Stacey Campfield's reasons for segregating the people who can get infected, and those who can't. In the senator's reasoning, it's a gay disease brought on by bestiality and "unnatural" sex acts. In early Chinese propaganda, it was a yuanshi (primeval) disease and the result of the Africans being "naturally" wild and uncontrolled. Both are bizarre and quite dangerously ignorant. *shakes head at the fact that this guy is a senator*

But anywho, yes. It's a common enough joke. Ricky Gervais in GTA 4 jokes about... SPOILER ALERT!... how the patient zero accedes to having received it from eating bushmeat to avoid having to admit that he had sex with an ape; and then confronts the chimpanzee who at first denies eating monkeys, but then agrees he did when the only other alternative is that he had sex with a monkey. Doesn't sound that funny when I say it like that. :P -- OBSIDIAN†SOUL 21:03, 29 July 2012 (UTC)

In his original post above, User:W203.27.72.5 claims that "the penetrative participant has a low chance of contracting the virus". Is this actually true? If so, wouldn't it imply that heterosexual men should have much lower rates of HIV than women? —SeekingAnswers (reply) 22:00, 30 July 2012 (UTC)

Check out out articles that give risks like our ones (e.g. HIV/AIDS). If it's a decent article, they nearly always give different risk estimates for penetrative/insertive and receptive intercourse, normally in the range of 1/5 and 1/10 difference although as our article shows, there tends to be fairly wide variance in estimates risk (although I think something went wrong with our insertive anal intercourse figure). However your assumption doesn't necessarily hold, it will depend on things like the frequency of high risk activity. Nil Einne (talk) 13:26, 31 July 2012 (UTC)

Your logic breaks down, SeekingAnswers, when you consider that the only reason women would have a higher rate of infection is because they contract the virus by having heterosexual intercourse i.e. with heterosexual men. If the men have a lower infection rate then the women will have a lower exposure rate. Then of course, there's the actual frequency of high risk activity as Nil Einne mentioned above. 203.27.72.5 (talk) 20:54, 31 July 2012 (UTC)

I could be wrong since I'm not an epidemiologist or even a statistician but I believe you're mistaken. I'm pretty sure that if you model an extremely simple system where you start off with an equal sex ratio of HIV infection and no HIV transmission from anything besides sex and presume only heterosexual intercourse and no difference in level of risky behaviour (beyond that due to the differences in insertive/receptive and sex ratio) and same effect of HIV and of course some degree of non-monogamy; you'd find that over time the sex ratio of HIV infection changes so that more women are infected then men. The ratio won't be as great as the difference between the risks of receptive/insertive. While the female partner may be at greater risk due to being the receptive partner, as the sex ratio of infection changes, the male will be at higher risk because a greater percentage of their putative partners have HIV; which I think is what you were referring to. But the ratio will still equilibrate at something other then 1:1. Remember not everyone with HIV is going to infect every single one of their sex partners, but if the believed difference in receptive/insertive risks are correct, the male partner has a greater chance of infecting their female partners (or will infect a greater number).

Of course such simplistic models have little relevence to the real world. A male who regularly engages with unprotected insertive anal intercourse with drug addicted sex slaves is going to have a higher risk then a female who only ever engages in protected receptive vaginal-penile intercourse in a monogamous relationship. (Ignoring other risk factors.) In fact I wonder whether a female who engages in unprotected receptive vaginal-penile intercourse in a monogamous will be at lower risk then a male who regularly engages in protected anal intercourse with drug addicted sex slaves. (And from a population standpoint, remember that if the woman is truly monogamous and doesn't engage in any other activity likely to infect someone else including childbirth and breastfeeding; she isn't going to infect anyone even if she is unknowingly infected by her sex partner who isn't as monogamous as she thought, something which does unfortunately happen.)

P.S. Hopefully none of my earlier examples offend anyone. I'm using them simply to illustrate the point rather then try to imply anything. One thing I'm pretty sure is correct is that the risk for a woman who only ever has sex with women (who similarly only ever have sex with women) is significantly lower (again ignoring other risk factors) then for a woman having sex with men for HIV and most STDs. Something which many of the anti same sex relationship groups seem to ignore when they speak of the evils of same sex relationships. But I guess many of the people in such a groups tend to be the sort that thing females don't matter so they it's not surprising if they don't care that they're asking women to put themselves at greater risk while at the same time speaking of the STD evils of men having sex with men.

Nil Einne (talk) 08:59, 1 August 2012 (UTC)

Actually, you're correct. I made a rudimentary model with a population that started with 10% male infection and 0% female infection and then assumed that every person had sex with a random person of the opposite sex in a iterative process. If women have a 10% chance of infection from sex with an infected male, and men have a 1% chance of infection from sex with an infected female, then by the 11th iteration the females' infection rate is higher than the males' and by the time half the men are infected, about 95% of the women are. 203.27.72.5 (talk) 20:52, 1 August 2012 (UTC)

Argon fluorohydride

Does HArF contain Ar(II) or Ar(0)? Double sharp (talk) 06:14, 29 July 2012 (UTC)

According to Argon fluorohydride it's a hydride, so that would make the Ar²⁺. 203.27.72.5 (talk) 06:18, 29 July 2012 (UTC)

Actually, no, it's Ar(0). Argon is more electronegative than hydrogen, but less electronegative than fluorine. Therefore, the oxidation number of hydrogen is +1, the oxidation number of argon is 0, and the oxidation number of fluorine is -1. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 06:28, 29 July 2012 (UTC)

Nope, from this article in Chemical and Engineering News,

"Many recent findings, including the first evidence for an argon compound, have come from matrix-isolation studies at the University of Helsinki in Finland (Markku Räsänen and coworkers). These studies have established the existence of a large variety of novel compounds, all stable up to 40 K. Included are HXeOH, HXeCCH, HKrCN, HKrCCH, and HArF. The last requires comment, because of the nonexistence of ArF2.

In all of these compounds, the vibrational spectroscopic findings indicate that the canonical form ([HNg]+Y–) contributes importantly to the binding of the molecules. The tiny proton is highly electronegative, and it bonds covalently to Ng in these molecules. The proton affinities of the noble gases are the following: He, 1.8; Ne, 2.2; Ar, 3.0; Kr, 4; and Xe, 6 eV."

So the form is [HAr]⁺F^-. Therefore the argon can only be Ar²⁺. 203.27.72.5 (talk) 06:56, 29 July 2012 (UTC)

Actually, having drawn the Lewis structures the argon must be Ar⁰ because of the relative electronegativities as Whoop said. The electronegativity of argon isn't extactly known, but the trends indicate it should be about 3.5 on the Pauling scale. 203.27.72.5 (talk) 07:56, 29 July 2012 (UTC)

Or if you want to get really technical, the oxidation number (as opposed to oxidation state) is what is denoted by Roman numerals (as in the OP question) and there the convention is for the electrons to be considered to reside with the ligands, which in this case is the H and F, so that would make the argon (II). 203.27.72.5 (talk) 08:01, 29 July 2012 (UTC)

Radon

Are any Rn(IV) and Rn(VI) compounds known to exist? If they do, could specific examples be given? Double sharp (talk) 06:19, 29 July 2012 (UTC)

From the same external article I linked to above,

"Although the easier ionization of radon leads one to expect the most extensive chemistry for that element, the high instability of even the most stable isotope has severely limited studies of it. L. Stein, of Argonne, established (in 1962) the existence of a fluoride--probably RnF2--but he and others were unable to confirm the existence of oxides or relatives of the perxenates."

So, it sounds like no, they cannot be confirmed to exist due to the instability of radon, but they do probably form. 203.27.72.5 (talk) 07:02, 29 July 2012 (UTC)

Most likely nobody tried to establish a research project on radon chemistry lately. Today there are good methods to do chemistry on instable elements, but not back in the 1960s.--Stone (talk) 12:40, 29 July 2012 (UTC)

Check out: likely yes, this one doesn't agree (an "X for dummmies" book, don't tend to trust them always)

Try a Google search: "radon RnO3"--R8R Gtrs (talk) 22:22, 3 August 2012 (UTC)

Locking car doors to prevent being thrown out

I've met a few people who always lock the car doors to prevent them from opening in case of an accident (and they try to convince me to do the same). I always thought the claim was weak for several reasons, but that's just based on my uniformed guesses. So the question is: will locking your car doors decrease the risk of you being thrown out of the car in case of an accident? Vehicle door is of no help.Sjö (talk) 08:45, 29 July 2012 (UTC)

Well, during an accident you could conceivably have something get caught on the door handle and pull it open, but this doesn't seem very likely. The better safety justification for locking doors is that it keeps a criminal with a knife from jumping in and carjacking you while stopped at a light. And, of course, kids or pets might manage to open the door while the car is in motion, and locking them makes this harder.StuRat (talk) 09:10, 29 July 2012 (UTC)

I would think that wearing a seatbelt would be a much better way of ensuring that you're not thrown from the car (or onto the steering wheel, or through the windscreen) in a crash. Mitch Ames (talk) 10:03, 29 July 2012 (UTC)

Car Talk says locking provides a small improvement in keeping the door closed in a crash, and that keeping the door closed is very important for overall protection of the occupant in ways unrelated to "staying inside".[3] DMacks (talk) 10:09, 29 July 2012 (UTC)

Bad idea. Very bad idea. Car door locks are designed in such a way that accidental opening is quite unlikely, unless the crash is so severe it becomes meaningless. And if you have at least half a brain you'll be wearing a seatbelt anyway. But locking the doors will make life more difficult for emergency crews to get you out, should you be dazed and/or confused. If they can't open the door, they'll use "jaws of life" gasoline-powered cutting tools to get you out, thereby writing off your car, which in many cases would be otherwise repairable. If your insurance company finds out you locked the door, they might pay out only the cost of the repair instead of the full replacement value. Quite apart from the risk of you being killed by fire (fires is not very likely in cars made by American manufacturers & their regional offshoots, but is something that does happen significantly often with Aisan cars). Should you be dazed/unconscious or whatever, and there is a fire in your car due to crushed wiring or whatever, you want bystanders &/or emergency guys to get you out immediately, before they get scared for themselves wrt explosions, and not be frustrated by a locked door. The exception is certain European cars eg Mercedes, that automatically unlock all doors if at least one airbag is triggered. Wickwack120.145.165.103 (talk) 12:21, 29 July 2012 (UTC)

A mild awareness of all factors is a good alternative to a rule. If you are driving a route that takes you across or beside a body of water, or into a tunnel, it is better to leave them unlocked. Escape in these situations could be a little easier (in the case of the water, it won't make a difference once the car actually enters the water, only before). Procedures for water entry are complex. The primary case for locking your door is when you don't always wear a seatbelt, in those cases, even if you don't notice it, you do lean against the door. If it is not closed properly, it can and often does, open and eject the occupant (much to their surprise) so locking the door is an added step which helps you actually check that the door is closed properly, and may indeed help stop it opening if it is faulty. Extra levels of protection are worthwhile, but fake strategies like driving with headlamps lit during the daylight hours should be avoided.

Short answer, LOCK your doors normally, UNLOCK them when approaching a waterway or tunnel and then lock them again afterwards. Probably a good idea to google some safety guidelines for tunnels as well, as Europe has a great many, and they are a whole world of hurt apart from regular roads. It is worthwhile knowing what to do, what not to do, and to generally avoid tunnels under certain circumstances. Penyulap ☏ 12:47, 29 Jul 2012 (UTC)

As you pointed out the OP is from Sweden and Daytime running lamps are required. I notice too that studies seem to say that DRL do improve safety in certain conditions. CambridgeBayWeather (talk) 15:23, 29 July 2012 (UTC)

Yes yes, and the oil companies tell countries to go to war as well, look at Tony Blair, Britain was his own personal militia to take the oil companies of Africa, so a little legislation is trivia. Headlights use electrical current from the alternator, which loads up the car's engine and uses more fuel for a given distance. The studies do not address the cause of the statistics, they only count the raw data. If you started a rumour that wearing a Poodle Hat whilst driving improved safety, then on the grounds that there are idiots who will believe anything you tell them, some idiots will take up the challenge and wear poodles whilst driving. If you then study the poodle group compared to the rest of us, you will also find they take ALL advice seriously, they always wear seat belts, always drive slow, never drink alcohol and so on. Those factors are showing through in the raw statistics and are published to perpetuate the myth. It's just another grapefruit diet sure you'll lose weight by starving yourself, it works, and the citrus co makes money. If you drive and see a RV with glaring lights you must look away from it, so how does that make it anything but invisible on this planet ? Hype. locking and unlocking must depend upon the environmental conditions and expected anomalies along the way, so computing the chance of requiring a speedy abandonment of the vehicle or the chance of car-jacking is probably sufficient to override the norm, which overall, would probably fall on the lock side so you don't fall out. (for worldwide) Penyulap ☏ 17:21, 29 Jul 2012 (UTC)

If the oncoming traffic is causing glare that is making you look away then there is something wrong with the oncoming vehicle. I've never had a problem with the lights of oncoming vehicles. How do you cope with the glare at night when all vehicles have their lights on? CambridgeBayWeather (talk) 23:11, 29 July 2012 (UTC)

As I have seen it done, drivers at night often hold their hand up to block the view of the headlights without blocking the view of the road, but I've only seen them do this in dark stretches where their eyes adjust to the darkness fully, I think you wouldn't see it as much in built up areas. Penyulap ☏ 03:30, 30 Jul 2012 (UTC)

Some very questionable advice above, about the importance of NOT locking the doors. Cars I've owned in recent years AUTOMATICALLY lock the doors when the car starts moving. Carjacking is a danger that is lessened by locking the doors. Rescue squads, firemen, and police just break the glass, rather than sending for the "jaws of life" when the car door is locked. I question the claim that the insurance company will pay less if the doors are locked. A locked door might be less likely to allow ejecting an unbelted idiot when the car flips.Edison (talk) 13:34, 29 July 2012 (UTC)

It's quite appropriate advice because I have taken into account the enquirers local conditions. They live in Sweden I believe. These factors come into account as carjacking is not universal. Insurance company rules vary widely between companies let alone countries. Penyulap ☏ 14:09, 29 Jul 2012 (UTC)

Btw, my comments on my userpage aren't about you, they are about the other Edison :) Penyulap ☏ 14:16, 29 Jul 2012 (UTC)

European cars such as Mercedes do automatically lock the doors as you start moving, but they also automatically unlock if an airbag is triggered - that is a safety requirement for the reasons I gave above. In the old days (not so old days with some brands) when cars were locked by a simple mechanical up/down button on the door sill, yes, that's what rescue chaps did - they bashed the glass, and then pulled up the lock button to open the door. But with modern cars, there's generally no such button - the deadlocks are electrically operated by either key or keypad. That may not be accesible, and an accident may cause an electrical fault disabling the unlocking (automatic unlock will happen momentarily before that happens). So, yes indeed, they will use "jaws of life" (which incidentally of course involves first smashing the glass out). Wickwack124.178.48.62 (talk) 13:52, 29 July 2012 (UTC)

"...when you don't always wear a seatbelt." With all due respect to Penyulap, but as I stated above, if you don't always wear a seatbelt, you're a half-wit. With and without accident statistics are very clear. See http://www.carrsq.qut.edu.au/publications/corporate/seat_belts_fs.pdf - not weraing a seatbelt increases the probablity of injury or death by up to a factor of 10. I owned a Ford Falcon - a very common car here in Australia. I was hit while doing 60 km/hr almost head on by another vehicle that went thru a red light at 80 km/hr - it wrote both cars off - wrecked them. I was wearing a seatbelt and walked away without a scratch. The other driver, who was in a small Japanese car, had only a slight scratch. Without a seatbelt, an 80+60 km/hr impact will seriously injure if not kill. Most folk who have been in a serious accident will tell a similar story. Wickwack124.178.48.62 (talk) 13:41, 29 July 2012 (UTC)

Again wearing seatbelts is a local variation, although cars in Australia are designed with the expectation that all occupants will wear a seatbelt, it is not the case in the United States. In the US, cars are sold with airbags that deploy with a far greater force than those in Australia, as it is every Americans right to be a moron and not wear a seatbelt. The manufacturers take that into account and make the airbag support the whole torso and head of the occupant, while in australia, it's just the ole noggin that needs attention, blimey mate get with the program. struth. Penyulap ☏ 14:16, 29 Jul 2012 (UTC)

Every state in the US has seat belt laws, only one state is lax enough to enforce the law just for minors, so I'm not sure what you are talking about when you say we have the right not to wear them...we have just as much a right to speed like a moron, meaning not at all. 71.195.84.120 (talk) 16:39, 29 July 2012 (UTC)

Cool, I wasn't aware of that, my memory must be faulty, but then, the airbag thing must point clearly to some large market where seatbelt use is lower than Japan or Australia for example. Penyulap ☏ 17:21, 29 Jul 2012 (UTC)

Airbags provide additional protection, especially in the event of a head-on collision. They used to be available only on luxury cars, but now they're pretty much standard issue in America. And just to reiterate, many states have what they call "click it or ticket" laws, meaning it is not a right to drive without a seatbelt. (In fact, driving itself is not a right - it's a privilege regulated by the government(s).) ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:03, 29 July 2012 (UTC)

Airbags are not meant to be used without a seatbelt. They form part of what's known as the Supplemental Restraint System. To quote the wikpedia article; "severe or fatal injuries can occur to vehicle occupants very near an airbag or in direct contact when it deploys. Such injuries may be sustained by unconscious drivers slumped over the steering wheel, unrestrained or improperly restrained occupants who slide forward in the seat during pre-crash braking". Increasing the force of airbag deployment for unrestrained passengers just sounds like a way to smack them even harder with the thing after they've already made contact with the dash or steering wheel. 203.27.72.5 (talk) 00:07, 30 July 2012 (UTC)

I assume the thing about locking cardoors is mostly aimed at reducing the odds that kids manage to open them at the wrong time; I'm really sceptical of the carjacking issue, which seems like a very low risk indeed, and it's not like you can't be carjacked straight through a closed window, unless you have bullet proof glass. Wnt (talk) 03:33, 30 July 2012 (UTC)

A locked door can still be opened from the inside (at least in every car I've tried it) so it won't prevent accidental opening, but there are often child safety latches (don't know what they are called in English) that disengage the inside door handle.Sjö (talk) 12:56, 30 July 2012 (UTC)

It is written in the article itself, outside the US, airbags are wearer as they are based upon the idea that people wear seatbelts more often, that is how they do the testing. I'm not saying people don't usually wear seatbelts in the US, they do, I'm saying the statistics vary according to country. I'll be happy to eat my keyboard and post the pics if every country wears seatbelts as often as the other. Penyulap ☏ 03:41, 30 Jul 2012 (UTC)

Having rules against not wearing seatbelts has nothing to do with the percentage of people who do, or the manufacturers efforts to compensate appropriately for it. Copyright. they have rules against it too, doesn't mean nobody does it. Penyulap ☏ 03:43, 30 Jul 2012 (UTC)

Having rules, publicising those rules and (perhaps most importantly) enforcing those rules with penalties for non-compliance probably does affect the percentage of people who wear seatbelts. At least the Western Australian Office of Road Safety seems to think so. Mitch Ames (talk) 10:04, 30 July 2012 (UTC)

Kinky tails on asian cats

Does Wikipedia have an article on the genetic defect which cause many cats from Thailand and Malaysia to have kinky tails? -- 203.82.81.154 (talk) 12:09, 29 July 2012 (UTC)

I've not found one, but I found this article which says "Kinked tails are seen commonly in many breeds of cat, particularly Siamese, Burmese and Oriental breeds. The kinks typically result from deformities of the bone and are listed as defects by most breeding authorities. However, they are usually only of aesthetic relevance as they cause no pain or discomfort to the cat." I would suggest that because the deformity is of no real significance, there's not a lot written about it, and my searches so far have confirmed it. --TammyMoet (talk) 12:45, 29 July 2012 (UTC)

my daughter has apha thalassemia

moved from Talk:Thalassemia#my daughter has apha thalassemia

my daughter has alpha thalassemia and I'm trying to get a better understanding of this. The doctor have advise that she cannot marrie anyone who has the same trait. what will effect will it cause when thry have a child together?

[Author unknown] 86.136.221.113 (talk) 11:36, 27 July 2012 (UTC)

I think this is worthwhile answering, please assume good faith. Penyulap ☏ 12:32, 29 Jul 2012 (UTC)

Genetic counseling definitely crosses into our policy of no medical advice. The original poster should find a genetic counselor to explain this in more detail. The doctor in this case was simply indicating that by classical Mendelian inheritance, someone who expresses alpha thalassemia is usually someone with a double-recessive of the gene in question. If they procreate with someone else who is also a double-recessive, 100% of their children will be double-recessive. If they procreate with someone who is merely a carrier (one copy of the thalassemia gene, which is not enough to express the disease), the children will have a 50% chance of being a double-recessive and a 50% chance of being only a carrier. If they procreate with someone who lacks the thalassemia gene altogether, their children will be 100% carriers. The probabilities of classical genetics are straightforward, but the real-life implications and the real-life complications are often not — and this is why a genetic counselor should be talked to. --Mr.98 (talk) 13:18, 29 July 2012 (UTC)

For more information on what Mr.98 is talking about, see autosomal recessive (also linked in the first sentence of thalassemia). --Tango (talk) 21:56, 29 July 2012 (UTC)

The above explanation may be applicable to beta thalassemia but is incorrect for alpha thalassemia, which results from the expression of two pairs of genes. --202.28.181.200 (talk) 09:46, 30 July 2012 (UTC)

You're right — the genetics are much more complicated than I'd realized. It actually depends quite specifically on exactly the way genome is expressing in the daughter and the potential mate -- you get very different results if you make different (legitimate) assumptions (the most common form of alpha thalassemia is either -/a -/a OR a/a -/-, and these produce very different Punnett square crosses with others of the same or the alternative form). The results can be anything from a carrier with almost no expression, to a fetus that cannot survive outside the uterus. The good news is that there is probably more flex to this than the original doctor said; the bad news is that the bad results could be even worse than I originally assumed. Again, a genetic counselor is definitely needed in this situation. --Mr.98 (talk) 15:09, 30 July 2012 (UTC)

Resources we can offer: We cannot comment specifically on your daughter's condition. However, we can suggest you read the articles Thalassemia, for a broad overview, and Alpha-thalassemia for the condition you are asking about. The external links sections at the bottom of these articles will suggest other websites, resources, and support groups you may find informative, likely more informative than we can be. Specifically the section Types in the Alpha-thalassemia article describes the concern for potential different effects on a child depending on how many copies of the affected genes it inherits from each of its parents. μηδείς (talk) 17:33, 29 July 2012 (UTC)

I certainly agree that we should not suggest whether they should marry or not. However, we are here to assist in research, even if it is not as notable as that of Augusto and Michaela Odone. I am glad you have given some guidance towards research, I would not like to see someone genuine turned away from the project if they are earnestly seeking to learn more. Penyulap ☏ 14:23, 29 Jul 2012 (UTC)

Don't forget, Kainaw's criterion is there if you're unsure about answering medical questions. BigNate37_(T) 15:12, 29 July 2012 (UTC)

My hesitation to go into any more detail comes from the fact that there can be many individual caveats to such an explanation. I attempted to answer the question in general terms as to what the doctor was probably trying to say, but even then I hesitate to put words into a doctor's mouth. Basic Mendelian genetics is relatively straightforward, but real genomes are usually much more complex, even for very simple traits. --Mr.98 (talk) 16:06, 29 July 2012 (UTC)

Oh, it wasn't my intent to call your judgment into question! Apologies if that's how it sounded. BigNate37_(T) 16:15, 29 July 2012 (UTC)

Please see http://ghr.nlm.nih.gov/condition/alpha-thalassemia, http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001613/, http://www.aafp.org/afp/2009/0815/p339.html, and http://asheducationbook.hematologylibrary.org/content/2009/1/35.long 207.224.43.139 (talk) 21:33, 29 July 2012 (UTC)

Collimated electromagnetic field

Is it possible to collimate electromagnetic field into a beam similar to a laser? ScienceApe (talk) 16:20, 29 July 2012 (UTC)

A laser beam is a collimated electromagnetic field. Do you mean a static, non-oscillating field? If so, I'm pretty sure the answer is no, except in the interior of structure such as a coil. Looie496 (talk) 16:27, 29 July 2012 (UTC)

Do the lines of force of a magnetic field count: [4] ? StuRat (talk) 19:00, 29 July 2012 (UTC)

Those are not collimated -- see collimation. Looie496 (talk) 19:17, 29 July 2012 (UTC)

A directional antenna looks different at each wavelength. A parabolic dish antenna, or a Yagi, serve to collimate an RF electromagnetic field to some extent. At optical wavelengths, we tend to use refractive optics - that is, lenses - rather than reflective optics (mirrors) - because we can conveniently build such effective, compact structures. But, if you ever look at a radio telescope, you'll see that it's just a Newtonian telescope mirror designed to focus a very large wave.

Finally, keep in mind that a laser is not just a collimated beam. It is a special type of light amplifier - and as a side effect, produces monochromatic light, which is very easy to collimate. You can collimate a beam of light even if it did not come from a laser source. So, by the same token, we can create amplifiers at other wavelengths to create strong radio or other electromagnetic waves; and we can also collimate those beams using appropriately designed "optics" suitable for the frequency. Nimur (talk) 19:28, 29 July 2012 (UTC)

No. (K.I.S.S.) Penyulap ☏ 03:50, 30 Jul 2012 (UTC)

Penyulap, while your answer was certainly succinct, it is also entirely incorrect. A laser beam is an electromagnetic wave. And, as earlier answers have explained, the concept can be extended to other electromagnetic radiation. Brevity is no substitute for accuracy. Nimur (talk) 14:28, 30 July 2012 (UTC)

de-colorized iodine

I saw something in the first aid aisle called de-colorized iodine. How do they de-colorize iodine? Does it affect its properties? --Wrk678 (talk) 18:03, 29 July 2012 (UTC)

From what I can see online, it is probably potassium iodide, but might be another iodine compound -- you will probably see exactly what it is if you look at the ingredients label. If it is indeed an iodine compound, the properties will be quite different from those of ordinary tincture of iodine. Looie496 (talk) 18:24, 29 July 2012 (UTC)

I'm not sure what that would be doing in first aid. My understanding is that the usual first-aid use of iodine is to kill bacteria (and viruses, I suppose) by oxidation; potassium iodide is not going to oxidize anything. Sometimes KI is taken orally when there are worries about iodine-131 in the environment after a nuclear mishap, but that's not a standard first-aid concern.

Tincture of iodine isn't used that much anymore because there are safer alternatives (and maybe because big brother is worried about people using it to make meth). --Trovatore (talk) 21:34, 29 July 2012 (UTC)

Sorry, I thought "tincture" was the term for the usual brown stuff. Anyway, my take from what I saw scanning the web is that "de-colorized iodine" is a product whose utility for first aid is, um, not well established. Looie496 (talk) 23:14, 29 July 2012 (UTC)

isint potassium iodide yellow? And how are the properties different?--Wrk678 (talk) 21:18, 29 July 2012 (UTC)

The article on potassium iodide explains why KI yellows due to impurity or age. BigNate37_(T) 23:21, 29 July 2012 (UTC)

There is also potassium triiodide which is likely what our OP is asking about. You make it by dissolving iodine in KI solution. Graeme Bartlett (talk) 06:58, 30 July 2012 (UTC)

But that solution is not colourless (which I assume is what is meant by "de-colorized"). See the left most testtube in the picture under "Testing for Starch" 203.27.72.5 (talk) 07:24, 30 July 2012 (UTC)

Curiously, according to this De-colorized Iodine label it's just tincture of iodine, and the active ingredient is the alcohol, with the iodine and iodide being listed as inactive. 203.27.72.5 (talk) 07:39, 30 July 2012 (UTC)

In this particular instance, this is a clear case of angel dusting, where the amount of iodine is insufficient to have any effect or change the color, but is dishonestly marketed as if the iodine was in sufficient quantities to provide an antiseptic effect, when, in fact, the alcohol does that. Their ruse is rather transparent; they must feel they can sell it for more if people think it's an iodine antiseptic than an alcohol antiseptic. StuRat (talk) 08:19, 30 July 2012 (UTC)

What is exceptional about the human body ?

...relative to other animals. Here's what I came up with so far:

1) There's our brain, obviously, although the much larger size of whale brains suggests they much have abilities we lack, like remembering every detail of their lives, perhaps. We do have the greatest division of labor among any species, I believe, as a result of our brains.

Now for ones I'm less sure of:

2) The opposable thumb does give us the ability to use tools. However, this ability is shared by other primates.

3) Our permanent bipedal motion allows us to walk long distances using little energy, see farther, and also to carry and use tools more effectively. (We do, however, pay for it with a slow sprint speed and lots of back problems.) Ostriches and other birds seem to share this ability, however, and without all the negatives.

4) Our starvation response seems to allow us to survive a month or two without food. Short of hibernation, this seems pretty decent. How does this compare with other animals ?

5) Our adaptive immune system seems able to provide us with immunity to a wide range of diseases after we've been exposed to them. How does this compare with other species ?

6) Our eyesight seems to be good overall, except for the huge percentage of us who are near-sighted or far-sighted. While other species have eyesight that can magnify more, see additional wavelengths, or see in the dark better, etc., we seem to have decent combo, especially the parts involving our brain, like motion detection and pattern recognition. How does this compare with other animals ?

7) Our omnivore abilities appear to allow us to eat a large variety of foods, with the exceptions of decomposing food, feces, grasses and wood, and foods containing various toxins. How does the wide range of foods we can eat compare with other animals, such as bears ?

8) Our lifespan seems to be near the top end of most animals.

Are there any other ways in which the human body is exceptional ? StuRat (talk) 18:56, 29 July 2012 (UTC)

I wouldn't say humans are exceptional in precise ways like that. Historically, pretty much every claim of the form "Humans are the only animal that..." has been disproven. The combination of the things you mention may be exceptional, but I expect an animal can be found for each of them that is "better" than humans. I think the most exceptional things about humans are the extent to which we use language and technology (neither of those is unique to humans, but I don't think any other animals use them as extensively and in as advanced a form). --Tango (talk) 22:14, 29 July 2012 (UTC)

The most important thing about humans ecologically is that we are the most K selected animals for body mass on the planet. This is a direct result of the success of human culture as a survival strategy, and the long period of acculturation (for things such as language acquisition which it requires. See K and r selection. Basically animals can invest a lot in a few children or invest a little in a lot of children. The latter, r selected animals, tend to live very short lives, most only a year or a season, and some only a day or a month as adults. Whales and elephants are the most K selected non-human animals, and live about as long as us, but they hugely outweigh us. Each human life is a huge biological investment so far as reproduction goes. We can't reproduce successfully on average til our late teens. We can only successfully raise one baby every two years on average. Historically, women may have had 10 or 12 babies in a lifetime, but on average they only had two or three that survived to adulthood, a fact which has not changed with modern demographics. And the presence of grandparents is a proven success strategy with humans. This means we are selected for strong immune systems, big brains, and long life in general, with the traits that support it. Other animals of our body size tend to have small litters, like big cats, or one precocious offspring like deer. They become independent in the fist year and reproductive within a few years at most. Humans are the epitome of altricial animals. No other animal takes a year to be able to walk or swim. It is the huge reproductive investment in each human that makes us unique and so successful. μηδείς (talk) 22:17, 29 July 2012 (UTC)

• Our social and communication systems are light-years more complex than that of any other animal.
• We're tool users. Creating what other animals have to evolve to.
• We have the longest childhood/adolescent dependency period of any animal by far. The second closest are orangutans and elephants, whose children stay with their parents for up to 10 years.
• We're one of the few animals where the females have concealed ovulation.
• We're one of the few animals who sweat for thermoregulation. The only other I can think of atm are horses.
• Binocular vision gives depth perception. But it's also common among other predators.
• Trichromacy makes us remarkable among mammals. But pretty average to weak in terms of other animals like birds.
• For a large mammal, we're relatively hairless. I just thought of elephants and whales! LOL
• We're one of the few animals that have recreational sex. Though admittedly other mating animals probably don't know they're reproducing either.
• Lactase persistence, we're one of the few mammals that can still derive nutrition from milk at adulthood. At least the humans who've been lucky enough to inherit the several mutations for it. Also random : don't feed your cat milk, they like it but they can't digest it and get stomachache, kthx.-- OBSIDIAN†SOUL 22:49, 29 July 2012 (UTC)

On brain size, a more useful index than raw mass of brain tissue is the ratio of brain mass to body mass — see the Encephalization quotient. Basically a lot of any brain is taken up with the motor skills and regulatory work of a large body. So animals that have big brains relative to their mass tend to be using more of their brains for being smart. Dolphins come out well in that comparison, as do chimps. Whales, not so much, but they may be an exception in any case because of their ridiculous amount of mass. Elephants are quite intelligent despite the inflated brain size because of their mass — it's still larger than average. In any case, it's pretty clear that raw brain size isn't really the trick — the trick is having certain specialized organs in the brain wired up in useful ways.

Humans are not exceptional in that we possess any one thing that other animals don't. But we are fairly tailored towards complex linguistic, social, and cerebral applications. These paired with excellent hands for tool-making has, over the long term, made us feel fairly dominant. (Whether we are dominant is an open question. Insects still have a one-up on us in terms of raw numbers and future prospects. From the point of view of krill, humans have just shown up and haven't been doing too much of interest.) --Mr.98 (talk) 23:21, 29 July 2012 (UTC)

You do realize biologists consider dolphins whales? μηδείς (talk) 00:39, 30 July 2012 (UTC)

Our dolphin article says "Dolphins are marine mammals closely related to whales and porpoises". This isn't the same as being a whale. StuRat (talk) 02:24, 30 July 2012 (UTC)

(ec)I think Looie is by far and away the most qualified to comment on this but my understanding is that whales need large brains just to control and receive feedback from their massive bodies. I don't think there's any suggestion that they have super abilities to remember everything or anything like that. 203.27.72.5 (talk) 23:22, 29 July 2012 (UTC)

I am glad you assigned winning prize in the spelling bee to the student who, because he was absent on the day of the test, didn't get any questions wrong. As for whale, I already posted the link to encephalization quotient. You might find reading it surprising, especially if you compare the size of the brains of sauropods and dolphins. μηδείς (talk) 00:37, 30 July 2012 (UTC) * 203.27.72.5 (talk) 03:25, 30 July 2012 (UTC)

When I said "Looie is by far and away the most qualified to comment on this" I was only refering to point 1) about the brain size since Looie apparently has a PhD in Neuroscience. But since you obviously feel left out, I left you a gold star :) 203.27.72.5 (talk) 03:25, 30 July 2012 (UTC)

I appreciate that star, I'll move it to my user page if you don't mind. I agree with Looie's statement below on the vagueness of the thread. But I think the answer is quite clear that our big brains, long childhoods, and longevity, making us the most K selected animal on the planet, all have to do with the success of culture and the traits it encourages the selection of. μηδείς (talk) 18:46, 30 July 2012 (UTC)

This topic is too diffuse for me. If it were only about brain size I might have something to say, but I don't like topics that are bound to meander all over the place. Looie496 (talk) 03:45, 30 July 2012 (UTC)

I think a major thing is that humans spend a huge amount of effort trying to learn and explore for the sake of interest and curiosity as opposed to simply finding out what we need to know to survive. I could be wrong about this being exclusive to us though. Juliancolton (talk) 03:01, 30 July 2012 (UTC)

We should not overlook fine motor skill. Bus stop (talk) 04:05, 30 July 2012 (UTC)

The answers seem to be going off track here. I want to know in what ways, if any, humans are PHYSICALLY superior to other animals, not all of the ways we are mentally superior. StuRat (talk) 04:07, 30 July 2012 (UTC)

How about our ability to sweat? An interesting and related article is Endurance running hypothesis. Bus stop (talk) 06:10, 30 July 2012 (UTC)

Regarding question #5 (how does our adaptive immune system compare with other species), see the article you linked to (Adaptive_immune_system#Alternative_adaptive_immune_system). All vertebrates except the most primitive ones (jawless vertebrates) have an adaptive immune system that is similar to ours. Vaccination is routine practice in fish farming, see for example this link. --NorwegianBlue ^talk 17:56, 30 July 2012 (UTC)

The ability to get scurvy (inability to synthesize vitamin C)? is fairly exceptional, though not unique. --catslash (talk) 18:48, 30 July 2012 (UTC)

Aren't humans the only animals capable of abstract thought? --146.7.96.200 (talk) 19:38, 30 July 2012 (UTC)

StuRat, this documentary video may interest you. (Warning: Some content may be objectionable to some viewers.) (Disclaimer: I do not necessarily agree or disagree with general or specific points made in the video.)

• The Superior Human? | Watch Free Documentary Online (1:13:33)

—Wavelength (talk) 20:21, 30 July 2012 (UTC)

Care to give me a summary, before I invest over an hour in watching it ? StuRat (talk) 23:05, 30 July 2012 (UTC)

The narrator discusses about 18 "alleged reasons" for the claim of human superiority, with "counterarguments" for all of them. The "alleged reasons" include: intelligence, language, culture, tool-making, opposable thumbs, bipedal locomotion, longevity, population, and position atop the food chain.

—Wavelength (talk) 23:56, 30 July 2012 (UTC)

But we're not even at the top of the food chain. 203.27.72.5 (talk) 01:34, 31 July 2012 (UTC)

Actually, we are on top of the food chain (we are an apex predator). Other animals only rarely eat humans, and we eat them more often than they eat us. So, if we aren't an apex predator, then no animals is. StuRat (talk) 05:13, 31 July 2012 (UTC)

Gustave regularly eats people. No one eats him. He's an apex predator. 203.27.72.5 (talk) 07:51, 31 July 2012 (UTC)

He may end up being eaten by people eventually, or maybe just made into belts. StuRat (talk) 09:39, 31 July 2012 (UTC)

I don't see this mentioned above, which seems surprising: an awareness of self and mortality which gives us the possibility of surving the destruction of the planet or a solar event by deliberately colonizing others, although we're not there yet; and, the imagination that we may arrive as visitors. Dru of Id (talk) 23:25, 30 July 2012 (UTC)

StuRat, you may also find this article to be interesting.

• Usain Bolt vs. The Cheetah: Olympians of the Animal Kingdom | Summer Olympics 2012 | LiveScience

—Wavelength (talk) 19:06, 31 July 2012 (UTC)

They just compare sprinting, where humans are at a distinct disadvantage. I'd expect us to to better in marathons. StuRat (talk) 03:23, 1 August 2012 (UTC)

From the original list, our eyesight is fairly average, which is in itself unusual: most animals specialize for something such as central vision, peripheral vision, low-light vision, etc. Not on the list is human endurance: there are a great many animals that can outrun us in the hundred-meter dash, very few who could keep up with us in a marathon, and most wouldn't even survive trying to complete a hundred-mile ultramarathon. --Carnildo (talk) 01:32, 2 August 2012 (UTC)

Isn't that number 3 on my list: "Our permanent bipedal motion allows us to walk long distances using little energy" ? StuRat (talk) 08:34, 2 August 2012 (UTC)

Most people couldn't survive trying a to complete a hundred-mile ultramarathon either. 203.27.72.5 (talk) 03:19, 3 August 2012 (UTC)

Melted cheese, part 2

I previously asked about why melted cheese tastes batter and got my answer, thank you.

I'm surprised more businesses don't sell previously melted cheese, considering how it makes a mess to melt it yourself, and you can't always melt it when on the road. Those portable string cheese containers, for example, could contain previously melted cheeses, which you could squeeze out like with Go-Gurt. It does seem to be potentially more messy than unmelted cheese, but we do eat plenty of other potentially messy foods, like grape jelly, and, in Wisconsin, at least, cheese curds. So, is there another problem with it ? Does it decay more quickly ? StuRat (talk) 19:40, 29 July 2012 (UTC)

Have you ever actually tried melting cheese and leaving it to sit for a day? The oil separates from the rest, and you get something approximating rubber coated with oil. It's not anything I would want to eat. It seems like what you are searching for here is Cheez Whiz. Looie496 (talk) 19:47, 29 July 2012 (UTC)

If you melt real cheese while somehow keeping the fat from separating from the protein matrix (with emulsifiers or melting salts usually or... dunno, very very slowly?), it will solidify into something else - processed cheese! :P -- OBSIDIAN†SOUL 20:09, 29 July 2012 (UTC)

Yes, processed cheese#Advantages sums it up. "...extended shelf-life, resistance to separation when cooked, and uniformity of product." The big clincher is that real cheese changes flavour and texture rather unpredictably when partially melted, which is not optimal from a convenience food standpoint. BigNate37_(T) 20:15, 29 July 2012 (UTC)