Wikipedia:Reference desk/Archives/Science/2012 July 16

= July 16 =

How long can you thrive/survive on water and calories?
My understanding is:
 * Without water you can survive a day or two.
 * With water but no food you can survive maybe a month or two.
 * With water, calories, and protein, you can thrive for about a month before symptoms of scurvy. It's not clear from the article how long you could survive (in ill health).

So I wonder:
 * What about the intermediate case of water and calories but no protein, e.g. sugar water but nothing else?

Thanks, --174.118.1.24 (talk) 00:55, 16 July 2012 (UTC)


 * This depends on the initial body mass index. Fat will be converted to calories. Protiens (e.g. muscle) will be recycled (to e.g. bile ducts) but lost over time without replenishment. The correct answer depends on the body mass index distribution and fat proportion of the population. 71.212.249.178 (talk) 01:11, 16 July 2012 (UTC)


 * Well, what I meant was, that there would be no caloric deficit. Or are you saying protein deficit would still trigger depletion of fat? --174.118.1.24 (talk) 01:24, 16 July 2012 (UTC)
 * I don't know how long it will take to actually die, but you might be interested in the articles Protein-energy malnutrition, Kwashiorkor, Marasmus and possibly also Essential amino acid. W203.27.72.5 (talk) 01:37, 16 July 2012 (UTC)
 * Yes, thanks, they are relevant but as you say, no timelines. --174.118.1.24 (talk) 03:43, 16 July 2012 (UTC)


 * Don't forget salt. That becomes a problem long before protein does. --Tango (talk) 02:41, 16 July 2012 (UTC)
 * I see! Thanks for pointing that out. I should also then wonder if there is any other deficiency that I haven't considered that manifests before protein? --174.118.1.24 (talk) 03:43, 16 July 2012 (UTC)
 * Iron? Iodine? All of the essential minerals? Vitamins (other than C which you have already considered)? 203.27.72.5 (talk) 03:50, 16 July 2012 (UTC)

The list of deficiencies that you will suffer from in a very short time would be very long. Since I can't find any examples of people who have tried to live on that diet, I can't say how all of those issues interact, but I agree with Tango that the most serious is Hyponatremia. Sodium (and also potassium) are very important in your nervous system and are constantly flushed from the body as they're highly water soluble. They're almost never in short supply, but with the constraints you've placed, your neuron function would be impaired very quickly. 203.27.72.5 (talk) 04:03, 16 July 2012 (UTC)

Sounds like someone filled their fallout shelter with D-rations and now they're second-guessing themselves. BigNate37(T) 04:08, 16 July 2012 (UTC)


 * The OP suggestion that you will not survive beyond two days without water is untrue, see this for just one example. As for surviving on water with no food, 2 months seems about right as (unfortunately) seen in Bobby Sands self imposed hunger strike. Richard Avery (talk) 09:50, 16 July 2012 (UTC)
 * Sands and the other hunger strikers ingested water and salt. They were young men in good health until their hunger strike, so probably able to live as long as anyone could from the general population.  They generally died in the tenth week of the strike; the seventh week was the worst.  They certainly would have lasted shorter periods, and had a more unpleasant time, but for the salt.  John M Baker (talk) 18:35, 16 July 2012 (UTC)
 * This also implies that, if he is a young man in good health, someone ingesting only sugar water and salt could survive for more than 10 weeks, maybe quite a bit more, although presumably he would start to suffer health effects from the lack of essential nutrients prior to that time (maybe in that difficult seventh week). I don't know how long someone ingesting only sugar water without salt could last, but I suspect less than 10 weeks, and it sucks to be that person.  John M Baker (talk) 19:29, 16 July 2012 (UTC)

Water, salt, sugar
So my question was based on several mistaken assumptions. Water and salt is what gets you a couple of months. Salt is actually a limiting factor even before sugar, let alone protein! So what about water, salt, and sugar then? For that matter is it even correct to put sugar immediately after water and salt, or is there a more immediate concern? --OP 174.118.1.24 (talk) 04:46, 17 July 2012 (UTC)
 * Well, oxygen comes first but that goes without saying. I think water, salt, and sugar would get an average person several months. There could be some other water soluble minerals or vitamins which come before protein. 71.212.249.178 (talk) 05:23, 17 July 2012 (UTC)
 * You may find the article Kwashiorkor to be informative. It is a syndrome caused by inadequate nutrient intake (especially protein) among people who get adequate calorie intake.  That pretty much describes your water-salt-sugar diet to a T.  People live for years with the syndrome, but can suffer serious physical and mental health and other quality of life issues, which can be life-long and debilitating even if their diet is eventually corrected.  The issue is especially acute in children, who can suffer developmental disorders as a result.  The condition does not appear to be itself directly fatal, but it does result in many sorts of oportunistic causes of death (i.e. weakened imune system leading to more infectious disease).  There are also articles on other malnutrition issues, such as marasmus (which is calorie deficiency) and Cachexia, which is a general "wasting away", but is more a symptom of other diseases than a disease unto itself.  For micronutrient (vitamin and mineral deficiencies) you'll want to research those individually; things like scurvy or goiter or rickets, but  many of those are chronic conditions not known to reliably cause death on their own, excepting perhaps scurvy.  -- Jayron  32  05:39, 17 July 2012 (UTC)
 * I expect, however, that people suffering from kwashiorkor do receive at least some micronutrients, which people on a water-sugar-salt diet would not (unless you consider salt a micronutrient), and I don't think it would be possible to live for years without micronutrients. In particular, I would expect that the lack of potassium would lead to a fatal case of hypokalemia at some point.  I don't know to what extent other micronutrient deficiencies would be fatal.  John M Baker (talk) 14:21, 17 July 2012 (UTC)
 * We can interpret "salt" pretty broadly. If you drink oral rehydration solution (which is water, sugar and various different salts) then things like potassium aren't a problem. I'm not sure if vitamins and minerals would get you first or if it would be essential amino acids. Can anyone find a source for that? If it's the vitamins and minerals, then it wouldn't be much of a stretch to add a one-a-day multivitamin to the water-salt-sugar diet. After that, I'm pretty sure it would be essential amino acids that would get you. You do need some fat in your diet as well, but I think you could go a long time without that. (This is all assuming you're an adult - children need different nutrients because they are still growing and babies need quite a lot of fat to support brain development.) --Tango (talk) 20:33, 17 July 2012 (UTC)
 * I don't know where the IRA hunger strikers got their salt, but it seems most likely that it was table salt, which does not include potassium. John M Baker (talk) 22:56, 17 July 2012 (UTC)
 * Also note this 1998 article in which a more recent hunger striker, 61 days into his strike, was expected to die soon due to his low potassium levels. In the event, Barry Horne ended his strike a few days later; his death three years afterward, from liver failure, is thought to have derived from his multiple hunger strikes.  John M Baker (talk) 23:11, 17 July 2012 (UTC)

Is it unhealthy to smoke tea?
My friend is putting tea in his tobacco to give it flavor. Is this bad? I really care about him. --50.13.107.190 (talk) 06:27, 16 July 2012 (UTC)


 * Well, smoking tobacco is itself unhealthy enough that you should discourage him from doing that in the first place. Also note that the phrase "smoking tea" is slang for smoking cannabis/marijuana, so it is unclear when you say "smoke tea" if your friend is smoking earl grey or is toking the refer, as the kids today say.  -- Jayron  32  06:34, 16 July 2012 (UTC)


 * Smoking camellia sinensis is not unheard of. I don't see any kind of harm it could cause, but I'm also not a chemist. Regardless, I'd be willing to wager that the tobacco smoke is doing far more damage to your friend than the tea ever could. Evanh2008 (talk 06:36, 16 July 2012 (UTC)


 * I don't see why inhaling the product of the incomplete combustion of one clump of plant matter is any better than another, additives from the production process not withstanding. 203.27.72.5 (talk) 06:55, 16 July 2012 (UTC)


 * Nicotine does not naturally occur in camellia sinensis, so there is that. Evanh2008 (talk 07:06, 16 July 2012 (UTC)


 * Nicotine, in the very small doses that you get in tobacco smoke, has a vanishingly small effect on your health. It's a stimulant, and that's about all. That's why nicotine inhalers, gums, patches, etc. are used to wean people off smoking cigarettes. The long term effects of smoking cigarettes has been widely studied. The effects of smoking tea leaves has not. They are going to contain a huge number of essential oils and other complex organic molecules for which the long term effects of volatilising and inhaling are unknown. At least with cigarettes you have some idea what you're doing to yourself. 203.27.72.5 (talk) 07:31, 16 July 2012 (UTC)


 * Just to clarify, the nicotine makes tobacco addictive, and the tar makes it harmful. I've never understood why cigarette companies don't go to nicotine inhalers as a permanent replacement for cigarettes, rather than just to wean people off tobacco.  That way, the customers could get their nicotine fix without the tar, and the tobacco companies would still make their profit, by selling the nicotine they extract from the tobacco, in inhaler form. StuRat (talk) 07:54, 16 July 2012 (UTC)


 * Yeah, that way they would also have a surer income source, since their customer base wouldn't keep dying. I think the major hurdle to that is the fact that nicotine inhalers and what not are dealt with as medications from a legal perspective, whereas cigarettes, cigars, pipe tobacco, etc. are dealt with as tobacco procucts. I've heard smokers complain that they would like to try those methods for getting off the cigarettes, but they all cost so much more even with the high sin taxes on cigarettes, and some have the added inconvenience of needing a doctor's prescription. 203.27.72.5 (talk) 08:03, 16 July 2012 (UTC)


 * What Stu said. The tar is the primary harmful ingredient in cigarette smoke, sure, but the nicotine is what makes it addictive. The addictive properties of nicotine are what encourage people to smoke, and very often to smoke in larger and larger quantities. Even if tea smoke produces as much tar and/or other harmful substances as cigarettes do, there isn't going to be the same level of physiological dependence that comes with nicotine. If you roll yourself a tea cigarette, the most addictive thing you're likely to get is... caffeine, maybe? Evanh2008 (talk|contribs) 08:05, 16 July 2012 (UTC)


 * It sounds like we could save millions of lives just by changing the regulatory and tax structure of nicotine inhalers. You'd think this would be a major campaign issue, in a US Presidential election year. StuRat (talk) 08:11, 16 July 2012 (UTC)


 * Between a sitting President who smokes and generally believes in taxation, and an opposing candidate who generally doesn't believe in taxation but also has a moral proscription against smoking, it's not likely to come up. ←Baseball Bugs What's up, Doc? carrots→ 13:46, 17 July 2012 (UTC)


 * Also, generally speaking, as per Cigarette taxes in the United States, most of the tobacco taxation is at the state level, which is beyond the reach of the Presidential candidates. In fact, it's a pretty low-level issue, as it's considered a "sin tax" by some, and from the libertarian standpoint it's a "voluntary" tax, in that tobacco is strictly recreational. ←Baseball Bugs What's up, Doc? carrots→ 13:55, 17 July 2012 (UTC)


 * There's nothing "voluntary" about that; voluntary status has nothing to do with why you want the good being taxed. The notion of a "voluntary tax" is usually applied to things that considered are user fees in disguise, like the tax on gasoline, provided it's genuinely earmarked for highway improvement &mdash; you pay it to use the public highways, and if you don't want to pay it you can find a way not to use them.  Of course it's not a perfect example, because maybe you want the gasoline for other purposes and you'd still have to pay the tax, but it's as close as the concept gets to making actual sense.  --Trovatore (talk) 08:06, 18 July 2012 (UTC)


 * See voluntary tax. StuRat (talk) 21:05, 18 July 2012 (UTC)


 * You see it. It supports me, and refutes Bugs. --Trovatore (talk) 23:19, 18 July 2012 (UTC)


 * I never made any claim of who it supports, I merely thought a link to the relevant article was appropriate. StuRat (talk) 23:21, 18 July 2012 (UTC)


 * Right, but high taxes on cigarettes and low taxes on nicotine inhalers is exactly what we need to improve the health of millions. So what makes the inhalers cost more ?  It seems to be a result of them requiring a prescription, so why do we require that ?   I think I will break this off as a new Q. StuRat (talk) 19:23, 17 July 2012 (UTC)


 * If you listen really carefully you can already hear the screams of "School kids will think it's candy!" and other assorted nonsense red herrings. 203.27.72.5 (talk) 08:26, 16 July 2012 (UTC)


 * Judging by the OP's edit history, I would guess the tea is from Turnera diffusa. 203.27.72.5 (talk) 06:43, 16 July 2012 (UTC)


 * Smoking anything is harmful, as the small particles inhaled when you smoke ("tar") are a lung irritant, and can cause inflammation or more serious problems. StuRat (talk) 06:47, 16 July 2012 (UTC)


 * You could always slap a swingeing tax on tea leaves - or has that been tried before? Alansplodge (talk) 18:53, 16 July 2012 (UTC)

Why do nicotine inhalers cost more than cigarettes ?
This was discussed briefly above, but I'm still not quite understanding what causes the high prices on nicotine inhalers. Also, are there places where they cost less ? StuRat (talk) 19:27, 17 July 2012 (UTC)


 * Well, Health Canada Advises Canadians Not to Use Electronic Cigarettes. I can't speak for your countries, but here the solution would seem to be addressing Health Canada's issues with the technology. At the very least, that would require studies and lobbying in direct opposition to tobacco companies' interests. It may also require more R&D, should independent studies find serious side-effects to the use of those technologies (though it seems unlikely). BigNate37(T) 19:32, 17 July 2012 (UTC)


 * See supply and demand. Concepts like value and the cost you pay for something are only very tentatively connected.  In our minds, we have a sense of "price justice"; that the cost you pay for an item should be somehow connected to the cost necessary to produce that item.  This is so far from economic reality to be laughably wrong, and yet most people believe that if item A costs twice what item B does, it must have cost twice as much to produce, etc. etc.  That isn't how it works, in any way.  If it was, it wouldn't explain why I can buy a 16 ounce bottle of soda at the front of a grocery story for $1.69 and get a 2 liter bottle of the same brand of soda at the back of the store for $0.99.  The only contributing factor to what you pay for an item is what the market will bear.  You have to pay high prices on the inhalers because that's what people will pay for them.  -- Jayron  32  19:49, 17 July 2012 (UTC)


 * So long as competition exists, then the price for which an item is sold should be closely related to all of the costs of producing and selling that item. That is, if it costs $1 to make, market, and sell an item, then you won't be able to sell it for long at $10, as a competitor will come along and undercut you on price and steal your customers.  There are, of course, various ways that competition can be prevented, such as price fixing (illegal) or patents (legal). StuRat (talk) 20:57, 18 July 2012 (UTC)


 * Where are 2 liter bottles of Coke/Pepsi produced sodas $0.99? We're only slightly gentrified and it's $1.99, rarely $1.25 on sale. And we still have to pay bottle deposit and 8.875% tax. Though I remember a wholesaler let you buy single 2 liters for $0.69 in '97. 12.196.0.56 (talk) 00:43, 18 July 2012 (UTC)


 * I can regularly get one brand or the other (Usually Pepsi, owing to where I live, but sometimes Coke) at $1.25 per 2 liter on any given day, and about once a month I can find it discounted at $0.99. That's American dollars.  -- Jayron  32  02:22, 18 July 2012 (UTC)


 * Jayron, you ought to click that link you just suggested yourself. The reason for the price discrepency between small and large bottles of soda is production costs, but you have to take into account all production costs inluding transport, labour stocking the shelves, refrigerated space being consumed in the retail outlet and the inconvenience imposed on the customer by having the product further away (i.e. The most visible locations in a store are themselves a scarce resource that must be expended on the shelving of different products) and so on so forth. Market information as a scarce resource also comes into play. The theory of marginal utility and the resulting supply and demand curves shows that in normal market conditions the amount supplied approaches the point of breaking even for both of these products. You just have to factor in all of the costs. 112.215.36.171 (talk) 23:29, 17 July 2012 (UTC)


 * You know what is strange, is when you agree with me, but take a tone that indicates you would be disagreeing with me. Every statement you made is illustrative of the exact point I was trying to make (that the real price and cost of an item is complex, and can't be estimated simply by comparing relative amounts) and yet you phrased it as though you were disagreeing with me.  I thank you greatly for providing additional evidence and support for my point, but am perplexed by the tone of the post that indicates you wouldn't be doing that.  Odd.  -- Jayron  32  00:27, 18 July 2012 (UTC)


 * Well in that case, I think you're just missing the point of StuRat's question; why don't the tobacco companies lobby for a change in the regulatory structure so they can cheaply sell mass produced nicotine inhalers that don't have the same health effects as cigarette smoke? Do they like killing people? 112.215.36.171 (talk) 04:21, 18 July 2012 (UTC)


 * There's a huge supply infrastructure to producing cigarettes, beyond simply the companys that make and market the final product. A complicated (and arcane) system of tobacco growers and warehouses and auction systems still exist to this day, and have a vested interest in not upsetting the applecart, as it were.  Living in a state where tobacco is king myself (North Carolina), the tobacco industry still has a huge political clout, and tends to be resistant to easy change.  For various political reasons, tobacco has been one of the few crops to resist corporitized farming; large amounts of tobacco are still grown on small family farms, and for many small farmers tobacco is the most lucrative thing they can grow.  That's what needs to be overcome in order to cause any revolutioary change in the nicotine consumption industry.  And that's probably not going anywhere, as that lobby is still huge where it counts, especially on the state level.  -- Jayron  32  04:37, 18 July 2012 (UTC)


 * But why would any of that change ? The tobacco companies would still need to grow, buy, and warehouse tobacco, from which they would then extract the nicotine to put in the nicotine inhalers.  Unless there's some cheaper way to obtain nicotine I'm unaware of ? StuRat (talk) 04:51, 18 July 2012 (UTC)


 * I realize that "other factors" contribute to the final cost, beyond the raw materials. I'm asking which other factors those are, in the case of nicotine inhalers.  Dramatically lowering the cost and eliminating the prescription requirement would seem to help the cigarette companies, who could then sell more nicotine, and stop killing off their customer base.  And, since customers can use them just about anywhere, they might consume more nicotine that way.  Cigarettes seem like a bad business model, to me, between of the terrible PR and lawsuits and shrinking customer base, at least in the US. StuRat (talk) 04:15, 18 July 2012 (UTC)


 * But Stu, your reasoning implies that the existing cigarette companies would be able to control the market on nicotine inhalers. If the companies themselves don't believe that, they will absolutely resist changing the system. And even if they could, there is no rule that the executives of a company have anything approximating functioning brains. At least here in the US, corporations are notorious for resisting even wildly profitable changes to their business models. Someguy1221 (talk) 04:32, 18 July 2012 (UTC)


 * Unless there's some other cheaper way to obtain nicotine than from tobacco, the tobacco companies would seem to have an advantage there. StuRat (talk) 04:53, 18 July 2012 (UTC)


 * So you are correct! Synthetic nicotine is more expensive than plant-derived nicotine . Is it possible that e-cigarettes are less addictive than the real thing? Someguy1221 (talk) 05:27, 18 July 2012 (UTC)


 * Well, since nicotine isn't itself detectable by smokers, they do tend to associate the nicotine high with the tar in a ciggy, which can be a problem when trying to get smokers to switch to nicotine inhalers. They just don't seem "right".  But, if a new generation of nicotine addicts were started out on nicotine inhalers, this wouldn't be an issue.  However, to do this, the whole concept of only prescribing nicotine inhalers to cigarette smokers trying to quit has got to go. StuRat (talk) 05:52, 18 July 2012 (UTC)

UPDATE: I'd still like to see some type of breakdown of the cost of nicotine inhalers, say by raw materials, manufacturing costs, regulatory costs, lawsuit insurance, taxes, profit, etc. StuRat (talk) 20:53, 18 July 2012 (UTC)

Apparently, the reason nicotine inhalers havn't caught on is because they chose Charlie Sheen as their poster child. 112.215.36.171 (talk) 02:33, 19 July 2012 (UTC)


 * Searching for any such claim, I found a handful of forum posters claiming tobacco contains "other addictive alkaloids", namely, tobacco-specific nitrosamines. It is a curious idea, since these are produced from nicotine by opening the ring and some other fairly small alterations.  (oddly, I found  that describes the methyl group as being the source of the mutations, yet the n-nitrosonornicotine article claims it's a carcinogen.  Hmmm...)  Getting closer to the goodies, I found  which says that nornicotine is as potent as nicotine at some receptors, and it has a longer half-life in the brain.  Now, nornicotine is a "minor metabolite" of nicotine in the body, but it is also present in the source tobacco.  It would be damned convenient if you could genetically engineer a tobacco plant that contains solely nornicotine, and it turned out to give smokers their high without so much cancer (on account of the missing methyl that reportedly is what mutates the DNA) but I don't know it's true. Wnt (talk) 11:28, 20 July 2012 (UTC)


 * I'm confused. Are you saying that regular nicotine is a mutagen/carcinogen ?  I hadn't heard that.  AFAIK, it's the tar (pretty much everything else in tobacco) that's carcinogenic. StuRat (talk) 20:37, 20 July 2012 (UTC)

Experience of submariners ascending from USS Tang?
According to the article, USS Tang was hit by its own torpedo and ended up heavily damaged in 55m of water. 13 seamen evacuated the forward compartment and swam to the surface, 9 actually making it, and only 5 of those managing to survive until pick-up the next day. My question is, what did these guys experience from the moment they left the submarine until surfacing? Were they wearing any sort of survival gear? Did they just take the biggest breaths they could and then slip through a hatch and swim like mad for the surface? Were they wearing buoyant gear that pulled them upwards faster than someone could swim? How quickly can a human swim 55m under water? I assume they suffered horribly from decompression sickness? The Masked Booby (talk) 08:35, 16 July 2012 (UTC)


 * As for whether they free dived or used an escape apparatus; the article cites a reference that they used a Momsen lung. 203.27.72.5 (talk) 08:40, 16 July 2012 (UTC)


 * (ec) I'd normally expect them each to have a Mae West (life preserver), but, from the description, it doesn't sound like they had them. Decompression sickness only applies if you are exposed to depths for enough time for your body to adjust, then decompressed rapidly.  I would expect more rapid pressurization damage, like burst eardrums, in their case. StuRat (talk) 08:47, 16 July 2012 (UTC)
 * British seamen of that era used the blow and go technique to try to avoid some of the effects of rapid decompression. Don't know about US sailors though. 203.27.72.5 (talk) 08:48, 16 July 2012 (UTC)
 * Recent examination of the wreck of the Royal Navy submarine HMS M1 suggests that at least some of the crew attempted to swim to the surface from a depth of 73 metres, but none survived. The pioneering Davis Submerged Escape Apparatus was introduced to RN subs four years later in 1929. Alansplodge (talk) 18:30, 16 July 2012 (UTC)


 * A rapid ascent while holding one's breath will result in Pulmonary barotrauma or burst lung, resulting in gas embolism (air bubbles in the circulatory system). Not very good for you. Alansplodge (talk) 18:45, 16 July 2012 (UTC)

hot and sneezy
I've read somewhere that it is not possible to sneeze when you get hot. Am I living proof that this statement is wrong? Why do I sneeze when I become hot? Difficultly north (talk) 09:58, 16 July 2012 (UTC)


 * What do you mean by "hot"? One person's hot is another's cold.  It has been in the news later that the USA has had a heat wave and people died.  With a temperature that in Australia would cause us to put a coat on.  45 C can kill an Englishman, but a Saudi Arab would think nothing of it. Do you mean just hot enough to sweat noticeably?  Or hot enough to cause distress and/or risk to your safety?  I sneeze at the height of our summer here in Western Australia, where daily max temperatures run at around 42 C (average for hottest month about 39 C).  Not because I'm hot though. Ratbone121.221.41.113 (talk) 10:53, 16 July 2012 (UTC)
 * Those U.S. temperatures causing deaths have actually been 40 - 43 C. And in our desert, where most of us don't live, it hit over 49 C. While the low in the mountains was -4 C the same week (24 F to 121 F in the continental U.S., July 4-10).. Rmhermen (talk) 13:20, 16 July 2012 (UTC)


 * Our article Sneeze says (without a source) that a sneeze can sometimes be caused by a cold draught or a drop in temperature, but says nothing about sneezing being suppressed when you're hot.  As I've seen many people with hay fever sneezing at the height of summer, I doubt that's the case.  Rojomoke (talk) 16:57, 16 July 2012 (UTC)

Did you mean hot, when you said hot? 79.148.233.179 (talk) 18:09, 16 July 2012 (UTC)
 * OR Warning You can sneeze when you are hot, but that's not a story I will tell here. Bielle (talk) 23:39, 17 July 2012 (UTC)


 * Hahaha! Missed this.  My father once microwaved some jalapeños and almost killed himself, my mom, and her mother.  That story is retold every year on cinco de mayo. μηδείς (talk) 04:53, 18 July 2012 (UTC)

I was referring to when you suddenly warm up. After stress or on a hot British day (sat 20s-30s) or doing activity or have a hot flush. I can't comment on the first one. Difficultly north (talk) 11:16, 18 July 2012 (UTC)

Horticulture question
What is the best way to go about growing tropical fruit and veg in a damp, cool climate? Do I need to get a greenhouse? — Preceding unsigned comment added by 86.135.65.250 (talk) 14:45, 16 July 2012 (UTC)
 * I think one of the main problems is the roots not handling frost. You could try heat trace on them or some other method to monitor the temperature and then heat them above the survival temperatures. Anything above ground would effect the plants as well but not as badly as root damage I would think. You could 'bag' the tops and somehow keep those warm as well. They would probably still grow slower and produce less in cooler climates.--Canoe1967 (talk) 15:43, 16 July 2012 (UTC)
 * In Britain, where the OP geolocates, you really need a greenhouse. The San Francisco bay area, where I live, is a cool damp climate, but it rarely freezes and almost never snows, and a few tropical fruits, such as lemons and some other citrus, manage to grow okay. Looie496 (talk) 16:35, 16 July 2012 (UTC)
 * What you need is an Orangery ;-) Alansplodge (talk) 18:38, 16 July 2012 (UTC)


 * Not all "tropical" fruits have the same hardiness, let alone all varieties. For instance, this kiwi could almost certainly be grown in Britain with little special care (it was developed for Michigan) . Other plants can grow outside their natural zones with special care. Historically, espalier technique was used to improve fruit yield in Europe. I've heard of some crazy people who manage to "lay down" entire fruit trees for the winter, so that they can be mulched and protected, but I wouldn't recommend it. Lastly, many passiflora species are hardy to cold climates, and even the tropical ones can bear fruit if brought in to the house over winter. SemanticMantis (talk) 20:16, 16 July 2012 (UTC)

Are you saying that growing passionfruit should not pose a problem? Also, do I need a special soil for this? — Preceding unsigned comment added by 86.135.65.250 (talk) 13:30, 17 July 2012 (UTC)
 * http://www.crfg.org/pubs/ff/passionfruit.html it seems some varieties can handle freezing. This page has the soil needs as well.--Canoe1967 (talk) 22:44, 18 July 2012 (UTC)

3-pole magnetic field
In a universe in which a three-pole magnetic field was possible (I gather it is not in ours per Magnetic_field), what sort of shapes might such a field have?174.88.8.241 (talk) 18:24, 16 July 2012 (UTC)
 * I'm sure it is possible in the sense that one could describe a mathematics which would explain it. Tripartate symmetries like this are known in our own universe, though not in magnetism specifically (i.e. the three color charges from Quantum chromodynamics.  Not being a mathematician, a phycist, nor particularly imaginitive, I'm not sure I can conceive of what a magnetic tripole would look like, but I suspect that the geometry of a magnetic tripole mapped onto a universe with four spatial dimensions would obey similar mathematical rules as our current universe, which has a magnetic dipole mapped onto a universe with three spatial dimensions.  -- Jayron  32  18:36, 16 July 2012 (UTC)
 * Given that opposite poles attract and like poles repel, I was trying to think how it could work if there were 3 poles instead of 2. The closest I can imagine is some electromagnetic equivalent of "rock-paper-scissors". ←Baseball Bugs What's up, Doc? carrots→ 13:49, 17 July 2012 (UTC)
 * Changing "opposite" to "different" gives a less complicated way it would work, but maybe not as much fun.--Wikimedes (talk) 18:02, 17 July 2012 (UTC)

You may find the mathematics of multipole expansion enlightening. It is not possible to construct a field whose multipole expansion contains nonzero odd terms, and that is also consistent with the experimentally-observed behavior of magnetic fields. But, it's certainly possible to define a hypothetical field - in the mathematical sense - with arbitrary properties. Strictly, there's a very significant qualitative difference between having three "poles" and having three valid values for the magnitude (or "charge") of a pole; so the above comments about color charge should be interpreted very carefully. Nimur (talk) 18:24, 17 July 2012 (UTC)

Preserving sugar
In our article on preserving sugar it says:
 * The large sugar crystals dissolve more slowly than those of standard granulated sugar and do not settle in the bottom of the pot or rise up as froth to the surface. This reduces the risk of burning and the consequent need for stirring. It also allows impurities to rise for easier skimming. Because it minimises scum, it helps to make jams (UK) / jellies (USA) clearer.

This strikes me as odd. Larger crystals do settle more easily than small ones (I speak as someone who has grown innumerable crystals in a professional capacity over the years). And, surely it's the fact that they do settle that allows impurities (rather than sugar crystals) to float to the surface. But, conversely, if they do settle then the risk of burning increases, as does the need for stirring. Thoughts, anybody? Chris (talk) 19:08, 16 July 2012 (UTC)
 * It's a relatively short article stub, with an uncontroversial history. It's been years since any information was added to the article. It sounds as though you have some insight that could be helpful to other readers, so this is a case where being bold is the best course of action. BigNate37(T) 19:51, 16 July 2012 (UTC)


 * OK so what you've observed applies to the crystals you've worked with. But does it apply to preserving sugar crystals in a fruit/sugar/water solution? If so, amend the article. If you don't know, maybe someone who does can confirm or deny it. --TammyMoet (talk) 20:35, 16 July 2012 (UTC)


 * For what it's worth the words "The large sugar crystals … clearer" may be from my increasingly dodgy memory a verbatim copyvio from the back of a sugar packet. Whitworths, I think. I'll have a look down the supermarket tomorrow. I happen to remember it because I remember thinking "What?" when I read it (on the sugar packet) – "surely if they settle more rapidly they'd increase the risk of burning and need more stirring". My practical experience (as an occasional amateur maker of jam) is that preserving sugar behaves in exactly the same way as bog-standard granulated sugar for high pectin fruit, for instance gooseberries. For low-pectin fruit such as strawberries jam sugar does the job. Tonywalton Talk 23:35, 16 July 2012 (UTC)


 * "The large sugar crystals dissolve more slowly than those of standard granulated sugar and do not settle in the bottom of the pot or rise up as froth to the surface"
 * The first part of this sentence suggests that dissolving more slowly is an advantage. If so, it should be explained why it is. I suspect it is nonsense.  (I realize that I'm going out on a limb suggesting it is nonsense. I may be way off base.)  Wanderer57 (talk) 14:29, 17 July 2012 (UTC)

Shock wave faster than the speed of sound?
Can someone clarify this passage from me about a nuclear explosion effects:


 * At this point a shock wave forms at the surface of the fireball as the kinetic energy of the fast moving ions starts transferring energy to the surrounding air. This phenomenon, known as "hydrodynamic separation", occurs for a 20 kt explosion about 100 microseconds after the explosion, when the fireball is some 13 meters across. A shock wave internal to the fireball caused by the rapidly expanding bomb debris may overtake and reinforce the fireball surface shock wave a few hundred microseconds later. The shock wave initially moves at some 30 km/sec, a hundred times the speed of sound in normal air.

(Via here).

I get that shock waves from, say, a supersonic jet are caused by the jet moving faster than the speed of sound. I get that the expansion of an atomic fireball might be moving faster than the speed of sound, thus creating a shock wave.

But can the shock wave itself actually move faster than the speed of sound? This seems contradictory to me, but I am not a physicist. How does that work, if it does? I thought the shock wave was more or less a sound wave, and would be thus limited to the speed of sound? --Mr.98 (talk) 20:34, 16 July 2012 (UTC)


 * There may be a vague definition of a shock wave here. Your definition, a compression wave which does not actually move the air, and what they might be talking about, perhaps more properly called a "blast wave", where the air itself is blown away, potentially at much higher speeds.  One complication is that the blast wave also generates sound along it's front, so, in that sense, the sound is moving faster than the speed of sound. StuRat (talk) 20:42, 16 July 2012 (UTC)


 * "it's front?" μηδείς (talk) 21:32, 16 July 2012 (UTC)


 * The outside edge of the blast wave, similar to a front in war or a storm front. StuRat (talk) 21:37, 16 July 2012 (UTC)


 * Pssst, I think she was pointing out the errant apostrophe in "it's". See pedant. Jerk182 (talk) 23:44, 16 July 2012 (UTC)


 * Yes, perhaps instead of a barnstar, we need a pedant pendant we can give out, with a silhouette of someone wagging their finger. :-) StuRat (talk) 02:12, 19 July 2012 (UTC)


 * There's a bit of a trick in the way that the quote is worded; it's given away when they talk about the speed of sound in normal air. The air around a nuclear detonation is far from anything we'd call 'normal'.  In an ideal gas under equilibrium conditions, the speed of sound is roughly proportional to the square root of the absolute temperature; at hundreds of thousands or millions of degrees, the speed of sound is quite a bit higher, as the individual molecules in the gas are on average moving at much higher speeds.  In reality, the system isn't ideal, nor is it under equilibrium conditions, but you get the idea&mdash;the air heated by a nuclear detonation is going to be a lot hotter – and therefore faster – than 'normal'.  The RMS velocity of an oxygen molecule at room temperature is about 500 m/s; the RMS velocity at 300,000 K is about 15,000 m/s: thirty-fold higher. TenOfAllTrades(talk) 21:27, 16 July 2012 (UTC)


 * related question: Schlierenfoto_Mach_1-2_Pfeilflügel_-_NASA.jpg  in this photo (from shock wave), does the leading edge of the shock wave (near the nose) not propagate with a speed nearly equal to that of the plane (e.g. mach 2)? I know the propagation of the wave must quickly slow down as distance from the plane increases, but this seems like it could be an obvious example of a shock wave traveling faster than the speed of sound. SemanticMantis (talk) 21:37, 16 July 2012 (UTC)
 * There is – perhaps appropriately – something of a semantic issue. The nose of the aircraft is certainly travelling at mach 2, therefore the tip of the shockwave would travel at the same speed.  On the other hand, from one moment to the next, it isn't the same air molecules next to the nose of the aircraft; as far as the air is concerned, the shock wave really is only moving at the speed of sound.  The leading edge of the shock wave at the aircraft's nose isn't a physical 'thing'.  TenOfAllTrades(talk) 21:57, 16 July 2012 (UTC)
 * Shock wave: "Shock waves form when the speed of a gas changes by more than the speed of sound." Rmhermen (talk) 22:07, 16 July 2012 (UTC)

If you do the computations you find what TenOfAllTrades explained above. In case of a shock wave moving throug a medium, it is conventional to define the speed of sound to be that in the ambient state of the medium. The shock wave then moves "faster than sound", and the ratio of the speed of the shock wave and the speed of sound is called the mach number of the shock wave.

The reason why a shock wave can form at all is precisely because in a hot medium the speed of sound is larger than in a colder medium. So, if you start with a strong pressure wave, then in the compression phase the wave moves a bit faster than in the decompression phase. So, the compression phase will start to overtake the decompression phase and that eventually leads to the formation of a discontinuity in the pressure and density, which is precisely what an ideal shock wave is. In reality, there are also dissipative effects which smooths out the discontinuity. Also this will prevent small pressure from developing into shock waves. Count Iblis (talk) 22:10, 16 July 2012 (UTC)
 * Huh? Isn't there a missing angle in the above? A shock wave which is constant strength travels along its normal line which is not the direction of the plane. The shock wave has to be travelling faster than the plane to have a component equal to the plane in that direction... --BozMo talk 19:26, 17 July 2012 (UTC)

A secondary question (on shock waves)
Thanks for the above, it has clarified it a bit, though I am still a little confused. Here's a question that might get me out of my confusion: in the situation above, would the blast pressure wave hit you before the formal "sound" of the explosion hit you? Or at they one and the same (as I had assumed before reading about the shock wave being faster than the speed of sound)? --Mr.98 (talk) 01:46, 17 July 2012 (UTC)


 * They are the same until the speed of the blast wave slows below the speed of sound. 71.212.249.178 (talk) 03:08, 17 July 2012 (UTC)


 * I added to the title to make it more descriptive. StuRat (talk) 03:16, 17 July 2012 (UTC)

organic chemistry
Arrange in increasing order of basicity- furan,thiophene, pyridine. — Preceding unsigned comment added by Subimal giri (talk • contribs) 20:50, 16 July 2012 (UTC)


 * I assume this is a homework question. I suggest you read Base (chemistry) and Organic base and then our furan, thiophene and pyridine articles, and work it out for yourself. We don't do people's homework for them. AndyTheGrump (talk) 20:54, 16 July 2012 (UTC)


 * Arrange in increasing order of slackerdom: "students who post Q's online, expecting others to do their homework for them", "students who don't do their homework at all", "students who do their homework themselves, as intended". StuRat (talk) 22:35, 16 July 2012 (UTC)


 * Actually, checking the articles, I'm not sure we give enough information to actually answer the question (or at least not for someone like me, who was never much good at chemistry, and has forgotten what little he learned), though one would assume that if this is a homework question, the student should have already been given sufficient information to answer it. AndyTheGrump (talk) 23:20, 16 July 2012 (UTC)


 * The correct answer would seem to be first, second, third and home. ←Baseball Bugs What's up, Doc? carrots→ 23:39, 16 July 2012 (UTC)
 * Pyridine has a pKa of ~5.2, furan -> 35.6, Thiophene -> 33. Source.Smallman12q (talk) 02:17, 17 July 2012 (UTC)
 * You're comparing different types of values that you shouldn't- the furan and thiophene values are for deprotonating the neutral compound, while the pyridine number is for the acidity of the conjugate acid (the number that you actually want to determine basicity of the neutral species). Buddy431 (talk) 10:38, 17 July 2012 (UTC)

The answer lies in the relative basicities of ethers, thioethers and amines, while being careful to take into account the contributions of the various resonance structures. I doubt the marking academic would be impressed by simply looking up the pKa values. 112.215.36.171 (talk) 00:11, 18 July 2012 (UTC)

Is there a "how long you've been asleep"/awake calculator?
Or a graph by age? I can't seem to find one on Google. Shouldn't be too hard with sleep giving hours per night at certain ages, a curve fitting and an integration.


 * Yes, I have just programmed one. Count Iblis (talk) 22:55, 16 July 2012 (UTC)
 * Are you going to share it? Proportion of age asleep does vary by age, but why would you need anything more accurate than dividing age by three? 71.212.249.178 (talk) 05:17, 17 July 2012 (UTC)
 * They're many calculators that ask health questions and spit out how many minutes, months, years, seconds and Plutonian years you'll live and even one that just says "You will die!", so why not one that takes your birthdate and gives how long you've been awake? Maybe I want to know how many "8 year old me" lives I've had? Though I don't know how much to cut off for early-life amnesia so I'll just cut off realistic minimum/maximum amounts and get bounds. 12.196.0.56 (talk) 00:59, 18 July 2012 (UTC)

Could they DNA test athletes and their pee so they don't try to cheat by giving other peoples' urine?
A saliva swab should be enough for the first part, right? Is there enough DNA in urine? Maybe they'll give their own urine from a clean year instead. So they'll test for signs of chemical degradation/aging in the pee, unless very well preserved urine is required for/would be detected in the normal course of drug testing. But then athletes will cryogenically freeze their urine in liquid nitrogen, and reconstitute it later for giving while they're doping. Uh, we could take their blood, right?, but that's apparently too invasive of their rights as they don't do so now. And I guess they need all the blood they can take to beat 9.58 seconds. How long after the athletic performance can they test and it still works? Maybe if they test for the last event on the athlete's calendar to save him all of his blood he could've doped on the earlier races? Allow the drug tester to take the blood sampling amount out before the Olympics and put it back in after they take the drug testing sample out? Radioactive dating of the urine with a fast-decaying isotope? And also, would Usain Bolt run 9.59 seconds or more if he didn't pee before the race, avoid chains over circa 0.1% of his body weight, or evacuate his bowels? Will they eventually wear suits with golf ball-like dimples designed in supercomputers and the bib information printed on? Amputate their ears to save weight while racing and use stem cell-grown pinnae when not? Sagittarian Milky Way (talk) 23:38, 16 July 2012 (UTC)
 * Yes? 71.212.249.178 (talk) 00:42, 17 July 2012 (UTC)
 * I don't think there really is any DNA in urine. There are lots of things you could do to make drug screening more effective, but you have to balance a lot of factors, efficiency, practicality, cost, etc.. In situations like this, I default to the team of experts that has been paid to work this stuff out, instead of assuming my uninformed musings might come up with a method significantly better then what they have in place now. Vespine (talk) 00:46, 17 July 2012 (UTC)
 * Often you're right Vespine. But they managed to avoid NFL (USA's #1 sports league) drug testing till last year didn't they? 12.196.0.56 (talk) 01:52, 17 July 2012 (UTC) I'm OP on public computer.
 * Wouldn't assigning someone to watch them pee into the cup be far easier? A8875 (talk) 01:10, 17 July 2012 (UTC)
 * Apparently 20% of the population can't pee when people are watching them. They could use a camera I guess but if I were a girl I would not want videos of urine coming out of my pee hole anywhere. They have Whizzinators so testers would actually have to view the pee coming out of the urethra. And which gender watches them if they're bisexual? Would the female Muslim athletes like any of this nonsense? Or, the final word, Good grief, some sort of near future airport scanner style very quick spectroscopy scan I saw in a science magazine that only detects explosives but can be set to see urea molecules ensuring that there are no supernumary urine reservoirs. They'll use this one day. 2040 Olympics. Unless they stop using urine testing. 12.196.0.56 (talk) 01:52, 17 July 2012 (UTC)
 * I think sexual orientation is mostly irrelavant in a case like this. Some people feel more comfortable going to a male or female doctor, so I don't see why an athelete couldn't choose the gender of the preson doing the "watching". But i don't think people chose the gender of their doctor because they think the doctor is going to get a sexual thrill out of the experience. If anything it might be because they're worried they'll get a sexual thrill when it's innapropriate. Or I wouldn't be surprised if some people, like exhibitionists make their choice based on the fact that they LIKE showing their private parts to people of their preffered gender. Vespine (talk) 04:07, 17 July 2012 (UTC)

urine needs some serious work. There is DNA in urine. Cell-free DNA in urine has been the subject of modern research as well as how to best preserve that DNA. See: Smallman12q (talk) 01:33, 17 July 2012 (UTC)
 * Molecular Testing of Urine: Catching DNA on the Way Out, Clinical Chemistry August 2000 vol. 46 no. 8 1039-1040
 * A Method for the Ultra Rapid Isolation of PCR-Ready DNA from Urine and Buccal Swabs
 * A Method for the Ultra Rapid Isolation of PCR-Ready DNA from Urine and Buccal Swabs
 * Ah, great. The march of progress. 12.196.0.56 (talk) 01:52, 17 July 2012 (UTC)
 * So, now, what do the secondary sources say about whether they will wear tracksuits with golf ball-like dimples? 71.212.249.178 (talk) 05:15, 17 July 2012 (UTC)
 * Such aids have been banned in swimming after a spate of broken world records. See LZR Racer. --TammyMoet (talk) 09:05, 17 July 2012 (UTC)
 * There are a number of confusing claims above. While urine tests are more commonly used particularly in out of season testing, and generally preferred because they're less invasive, blood tests (in addition to urine tests) are used in the olympics. See, Use of performance-enhancing drugs in the Olympic Games, . I'm doubt it will be possible to detect autlogous blood doping via transfusion using urine (not that it's easy with blood). (Generally blood in the urine is taken as a bad sign, but I won't if enough normally end up in the blood that technically it may be possible to detect homologous blood doping via urine online.) A blood passport as recently in the media in relation to the Tour de France obviously requires blood. I don't think it's uncommon that it's easier or considered more reliable to detect certain things in the blood (or in the blood in addition ot urine), according to , it was done with EPO in the past although as our blood doping article and the source mentions, urine alone is now considered sufficient albeit somewhat controversially (but I'm not sure that blood helps the controversy since it appears to be about the ability to distinguish natural EPO from recombinant EPO). People mentioned Paruresis, but it's worth noting AFAIK there is no real provision for this in the olympics, see World Anti-Doping Agency. Urine collection is monitored, I've heard to the extent they athelete doesn't even hold their own penis (if male). I seem to recall there was a recent case I think at the olympics or just before (but not this olympics) where a participant failed to provide urine and it was suggest paruresis may be a factor, the WADA or someone said it's wasn't something they'd even encountered before. (Can't seem to find the case.) Some people were surprised by this since it isn't an uncommon condition, but others pointed out anyone with the condition would generally have failed to advance to the olympics because urine testing is widely used at earlier levels. Also while providing fake urine is a concern, I even seem to recall there was someone disqualified from the olympics for allegedly doing this a few years back, I don't think it's really that much of a concern compared to many of the other possibilities of cheating using drugs without detection given the level of observation done, see for example . I mean if someone started physically implanting something to provide fake urine, it wouldn't surprise me if ultrasounds started being used to detect that. The whizzinator may work in some contexts but perhaps not the olympics. (Edit: Forgot to mention I'm primarily thinking of male atheletes, there may be avenues for a female athelete whike under strict observation although I haven't looked in to it.) Nil Einne (talk) 06:47, 17 July 2012 (UTC)
 * According to, DNA tests on urine have been used to confirm who the urine belong to, but this appears to be primarily when officials are complicit in the cheating. It wouldn't surprise me if they're now a regular part of test since it probably doesn't add much to the cost, but I still suspect it isn't really that important in terms of in-olympics testing for the reasons mentioned above. Nil Einne(talk) 07:57, 17 July 2012 (UTC)
 * Found which describes collection observation in some US sports, I presume the olympics is the same or stricter. It also mentions ways atheletes have attempted to cheat in the olympics on urine collection including the method that is probably used in the case I mentioned remembering above. It sounds to me like only those who have perhaps never gone thru a normal olympics style observed testing would think they have a chance of using them. More sophisticated cheats know they won't work. I guess the catherisation method mentioned in the source above and  can't be detected via observation, but this would be difficult if you can suddenly called up for drug testing at any moment and aren't given any time alone once you're called up. And rejecting the first sample of urine as the earlier source mentioned also sort of kills the catherisation idea. In other words, DNA testing may have its merits, but the low tech solutions are likely the best methods to ensure you get what you want, a recent urine sample from the athlete.
 * DNA testing also opens up other complications, e.g. for a female finding foreign DNA in their urine stream may suggest they are careless, but perhaps not that surprising . The ClinChem link above also mentions other ways foreign DNA can end up in the urine stream. And of course adding your own DNA to some other sample of urine can't be that hard. You could seperate these out, but relying on them adds complications. Then there is the problem of the athelete using a clean sample of their own urine and trying to test if they're doing that. All in all, best to rely primarily on low tech. (To be fair, it sounds like I was correct above that foreign DNA can be used to detect the possibility of autologous blood doping so it may be something important to look in to.)
 * Nil Einne (talk) 11:11, 17 July 2012 (UTC)