Wikipedia:Reference desk/Archives/Science/2011 December 31

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December 31

How -or why- do interleukins produce fever?

How? — Preceding unsigned comment added by 88.8.75.198 (talk) 02:14, 31 December 2011 (UTC)

Fever#Pathophysiology seems to cover some related issues. --Jayron32 02:21, 31 December 2011 (UTC)

Shaving with boiling water

Most of the time I use an electric razor to shave, but I was having a wet shave this morning and got to thinking that my father used to always use boiling water to dip his razor in when having a wet shave. For the record he used a safety razor, not a cut-throat (and, if it matters, we are just talking about shaving the beard area). I haven't noticed this done elsewhere, and just checking our shaving page, as well as some 'how to have a good shave' sites on the internet, I can't see it recommended to use boiling water. I can guess that there may be some theory about the heat helping to swell the whiskers or improve the efficiency of the cut or something, but does anyone know any more about this, or whether there's any possible scientific validity to his old technique? --jjron (talk) 03:45, 31 December 2011 (UTC)

Possibly to kill bacteria that might be on the blade? ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:55, 31 December 2011 (UTC)

That would be my guess, although it seems unnecessary. I've cut myself shaving many times, and never had it get infected. The risk of burning yourself would seem to outweigh any benefit. StuRat (talk) 03:58, 31 December 2011 (UTC)

Hah, just reminded me of a classic Australian poem from 1892 about just that: The Man from Ironbark (full text here). Wonder if it could have come out of there, or if there's some historical precedent to that. --jjron (talk) 05:13, 31 December 2011 (UTC)

Shaving is more dangerous than you think, StuRat. While the purpose of the antiseptic agent in aftershaves is to prevent infection of cuts, deaths from infected shaving cuts are not unknown. Notable victims include Russian composer Alexander Nikolayevich Scriabin (it might have been a boil), Henry David Thoreau's brother John, Egyptologist George Herbert, 5th Earl of Carnarvon (yes, the Curse of Tutankhamun is death by shaving!), and U.S. Representative Michael F. Farley (via anthrax from a shaving brush). While we are all glad that you have survived so far, StuRat, your complacency is dangerous. Personally, I follow the lead of the men from Ironbark (where "flowing beards are all the go") just to be safe. (I've always heard that Reserve Constable Albert Alexander, the first patient treated with with injections of penicillin (he wasn't treated until he was already severely ill, and while he responded well to the drug, he died shortly after the supply ran out), was suffering from an infected shaving cut, but our article claims that he was accidentally scratched by a rose thorn in his mouth. I suppose that now I'll have to stop eating roses.) -- ToE 05:43, 31 December 2011 (UTC)

Actually that's a good point (and I should have thought of it earlier). Although it was before I knew him, I have a friend who spent months in intensive care close to death and ultimately lost close to a year of his life after a shaving nick at the hairdresser (shaving the back of his neck) went bad. It wasn't that long ago either, I think it was probably sometime in the late '80s. --jjron (talk) 06:40, 31 December 2011 (UTC)

I can't say with scientific accuracy, but I use a cutthroat and dipping it in boiling water between strokes feels more comfortable. @Baseball Bugs, I almost invariably get a rash if I don't use aftershave( I use spirit). @StuRat, The blade and the layer of water actually cools by the time it reaches my chin and feels "just warm".

I think the hot water may make the cream more effective and unclog the edge of the blade. A little scum at the cutting edge seems to make a big difference in the ease of shaving. Though I cannot discount the chance that I just don't like cold steel against my neck. Staticd (talk) 05:31, 31 December 2011 (UTC)

I personally dip the razor in hot water (not usually boiling, but fairly hot) because the hot blade contrasting with the coolness of my menthol-containing shaving cream works wonders for waking me up in the morning. I have never considered other possible advantages to this practice - it just feels so much better to me. Equisetum (talk | contributions) 11:33, 31 December 2011 (UTC)

For some reason I don't really have that much facial hair, and only need to shave once every two days to feel comfortable, and can use a single-use disposable razor for three months. And I usually run it under hot water before using it, it feels much better and the skin response is much better than when using cold water (i. e. shaving during camping or on a gas station in the middle of nowhere, if I have to, can be a drag). I saw my father dipping his razor in boiling water before shaving, and he did it exactly because of the germs. --Ouro (blah blah) 17:18, 31 December 2011 (UTC)

He actually boiled a kettle before shaving? --Tango (talk) 23:26, 31 December 2011 (UTC)

He got some from the kitchen usually, you know the morning routine, coffee, a cigarette and shaving. --Ouro (blah blah) 20:09, 1 January 2012 (UTC)

• Us girls know that it is better to shave in hot water as it causes the hairs to extend ever so slightly more. Consequently, when the shaved area cools, the hair retracts just below the skin line, and the area stays smoother longer. Mind you, we all shave in the shower anyway. Elen of the Roads (talk) 02:09, 1 January 2012 (UTC)

  Men know that too. If you're having a wet shave, then you make the beard area wet with hot water (unless you don't have any hot water or you think it's macho to use cold water). The hot water, together with the soap/foam, softens the hairs and makes them easier to cut close (I think the softness is more important than making them extend). You wouldn't use boiling water, though, since that would burn your face! This discussion is about dipping the razor in boiling water. I sometimes shave in the shower. It makes it much easier to get a close shave, but there is always the issue of the mirror steaming up. That may not be an issue for you, but shaving your face without a mirror is a little tricky! (Not impossible, though, if you're careful.) --Tango (talk) 04:09, 1 January 2012 (UTC)

I completely ruined my sideburns last time I tried mirrorless shaving - after that I go with a "designer stubble" look if there's no mirror to hand. More to the point, I have seen suction-cup equipped mirrors designed for shaving in the shower that have a surprisingly effective anti-fog coating, circumventing that problem. Equisetum (talk | contributions) 11:32, 1 January 2012 (UTC)

Prescription first aid kit

I'm blanking this question and all the responses. Serious, people, what are you thinking? We do not give advice on prescription drugs. What drugs to prescribe is a decision for the doctor writing the prescription and we should not be involved in any way. The OP is either a pharmacist or is working for a pharmacist, so should know far more about this stuff than we do anyway (and should know better than to ask random people on the internet this kind of question). Please do not replace this question or any of the responses without a clear consensus on the talk page. --Tango (talk) 14:48, 31 December 2011 (UTC)

This is being discussed on the Talk Page. Buddy431 (talk) 18:17, 31 December 2011 (UTC)

What fraction of calories in food are typically needed for digestion, e.g. to produce digestive enzymes ?

I found several answers on google, but none of those look very trustworthy

http://wiki.answers.com/Q/How_many_calories_are_burned_during_digestion says "up to 200 calories per meal" Another site (which is apparently blocked here) claims it is always below 100%

I'm looking for a trustworthy, scientific source here (wikipedia will do) 83.134.159.252 (talk) 14:52, 31 December 2011 (UTC)

Thermic effect of food would be the place to find that sort of info, but that only says that around 10% of food's calories are used to digest it. I can't find any specific figures, presumably due to the difficulty of measuring it. Assuming you don't have journal access, this or this should tell you more (the full versions are available for free). SmartSE (talk) 15:13, 31 December 2011 (UTC)

I can't see how it can always be less than 100%. There are things you can eat which fool your body into thinking they are food, like artificial sweeteners, but which contain zero or maybe one calorie. In such a case it must use more energy than that to digest. However, if you think this is a good weight loss strategy, think again. Your body will become very hungry for real food after being tricked like this. StuRat (talk) 16:09, 31 December 2011 (UTC)

Thanks. I was just looking for a good source to use in a discussion, I am not planning to base a weight loss strategy on this. 83.134.159.252 (talk) 06:39, 1 January 2012 (UTC)

See Negative-calorie food for Wikipedia's (very brief) article on this. --Carnildo (talk) 02:08, 3 January 2012 (UTC)

Lower resting O2 saturation in endurance athletes

Should endurance athletes typically have lower resting blood O2 saturation than normal (as measured by a pulse oximeter)? Say around 92%. Sławomir Biały (talk) 15:06, 31 December 2011 (UTC)

I don't see why. They should be able to get the normal saturation with fewer breaths, though. StuRat (talk) 16:11, 31 December 2011 (UTC)

They only reason I can see for an athlete having low resting sats is if they are doing altitude training, in which case they'll have the same low sats as anyone at high altitude (at least until they are acclimatised properly). If you have been measuring your own sats are are concerned about them, you should see a doctor. They will be able to tell you pretty quickly whether you have anything to worry about. --Tango (talk) 16:33, 31 December 2011 (UTC)

Are lotteries time travel proof?

Let's say you have the winning numbers of a lottery and you travel back in time to purchase a ticket. Doesn't chaos theory mean that your actions in purchasing that ticket would affect the circumstances of ball/number selection selection? That you would throw things askew just enough to reduce your odds of winning? I mean, go into a store and buy a ticket, but in so doing cause every subsequent person to purchase theirs roughly 30 seconds later than they would have thus causing thousands of numbers to be different than they were. Or is your contribution to the events that determine the numbers so small that you'll probably still win? Some lotteries use machine generated numbers. Maybe they could add variables to their number generation like amount of tickets sold and at precise times to better protect against time travellers. Lotteries should be enacting measures to protect against time traveler schemes, I would think. It would be really unfair to the rest of us standard timeline blokes who buy tickets if they didn't. — Preceding unsigned comment added by 90.9.15.204 (talk) 21:38, 31 December 2011 (UTC)

I'm no expert, but it would seem to me that the chance of event A (purchasing a ticket) affecting event B (lottery drawing) would be dependent on the initial proximity of the events and the elapsed time between the two events, as the effect of event A expands over time. This is related of the Chaos theory#topological mixing aspects of Chaos theory. For example, if you bought your ticket at a convenience store that is later visited by the lottery operator(s), you could easily introduce a change in timing or behavior that causes the operator to run the machine slightly differently. However, if you bought your ticket in a different city shortly before the drawing, there would be a much smaller chance of affecting the outcome. -- Tom N (tcncv) talk/contrib 23:20, 31 December 2011 (UTC)

You are assuming that time travel actually changes the past. The simplest theories of time travel have the past staying the same. Say you watched the lottery at 6pm and then went back to noon to buy your ticket. You experience that noon twice. Those theories say that the first time you experienced that noon there was a 2nd copy of you buying the ticket. When you go back in time, you are just that 2nd copy that was there all along, so nothing changes. If that's the case, then your lottery scam should work perfectly. --Tango (talk) 23:34, 31 December 2011 (UTC)

I don't know what you mean by theories of time travel. Time travel is not possible. There is no point in discussing what would happen if you do it. It's like discussing what would happen if two objects could occupy the same space or if we could travel faster than the speed of light. It doesn't make sense. 88.8.76.174 (talk) 23:58, 31 December 2011 (UTC)

That's a bold assertion, one that a good many scientists appear to have wasted their time attempting to learn otherwise. Our own articles aren't so certain, although not so much as to suggest being able to go back and buy a lottery ticket. Mingmingla (talk) 00:19, 1 January 2012 (UTC)

Time travel would require some kind of exotic matter or similar that we have no reason to believe exists, but it isn't impossible that it exists. --Tango (talk) 00:59, 1 January 2012 (UTC)

@88.8.76.174: That is not true. I have travelled through time all my life. Just because I go forwards instead of backwards at a steady pace it is not considered to be special. Von Restorff (talk) 10:54, 4 January 2012 (UTC)

If I read the winning number for the lottery, then dash down to my basement, select suitable Tesla coils, pieces of loadstone, vacuum tubes, and stone chips from Stonehenge, build a time machine, and travel back to a time before the drawing to purchase a ticket with the winning numbers, the simplest explanation of what would happen next is that a parallel time-space continuum would then follow, in which I had the winning ticket. "Changing history?" No, creating an alternative history. There are "multiverse" theories in which, is you drop the toast, it lands jelly side up in one continuum and jelly side down in a different one, or in which a different continuum exists with a branching at every possible quantum event. Thus there is no contradiction, and no mysterious forces need manifest themselves to "prevent us from changing history." Edison (talk) 00:28, 1 January 2012 (UTC)

I think the immutable past theory is simpler than the the parallel universe theory, for the simple reason that it doesn't require additional universes. With an immutable past, you can do whatever you like in the past but it won't change anything because the future you did exactly the same things the first time round. There are no mysterious forces involved, it's just a closed loop. --Tango (talk) 00:59, 1 January 2012 (UTC)

If people from the future could mess with our timeline, their would be a lot more to worry about than who wins the lottery. StuRat (talk) 00:31, 1 January 2012 (UTC)

If people from the future could travel in time, why aren't they appearing here where (or when?) I am, every now and then? 88.8.76.174 (talk) 03:15, 1 January 2012 (UTC)

See Time_travel#Tourism_in_time. --Tango (talk) 03:57, 1 January 2012 (UTC)

One way to find out time travelers from the feature would be to spot anomalies. Like in the movie "12 Monkeys" where the main character is found on a photograph from World War 1, despite living in present time, especially beating any system with "impossible" odds like the stock market etc.. Maybe the present is just the most probable time point. Electron9 (talk) 06:21, 2 January 2012 (UTC)

"Maybe the present is just the most probable time point." - I like that. Not entirely sure what you meant, but for me, it suggests time as a probabilistic phenomenon: we occupy the present as an electron occupies the most likely position in its cloud - or something... Time as a bell curve, with the present at the peak probability - you have to use a improbability drive to get into the future or past... Sorry, just thinking aloud here Adambrowne666 (talk) 06:37, 2 January 2012 (UTC)

However, some people are bound to do amazingly well in the stock market just as some people are destined to win the lottery, not because they knew the results ahead of time, but just because so many people attempt it. So how would you distinguish the lucky from the time travelers ? Personally, I'd look for the tin foil clothing :-). StuRat (talk) 06:31, 2 January 2012 (UTC)

Its depend on the forth you act , and the justis that organis that on the top - the good for last , and money only for good thing anles you act strongly on time travel .Thanks Water Nosfim — Preceding unsigned comment added by 212.199.175.104 (talk) 12:30, 1 January 2012 (UTC)

I'm sorry, but that doesn't make any sense... --Tango (talk) 13:01, 1 January 2012 (UTC)

sometims when you travel you prefer to act at cases like life and death and live it on top , staf like money stay on the side and gets like glass -you can look throw them if you not act strong enafh . thanks Water — Preceding unsigned comment added by 77.127.6.242 (talk) 13:27, 1 January 2012 (UTC)

Water Nosfim appears to be editing from a parallel universe in which the English language developed in a very different way. Dbfirs 17:52, 1 January 2012 (UTC)

You wouldn't need to buy the ticket in a store and delay the next customers by so much: instead you can buy a lottery ticket over the internet or mobile phone from a prepaid card. – b_jonas 12:36, 2 January 2012 (UTC)

You could always invent time travel and let us know how you get on. Mrlittleirish 08:36, 4 January 2012 (UTC)