Wikipedia:Reference desk/Archives/Science/2008 November 8

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November 8

Deceptive practice?

I was in the supermarket today and I came across non-dairy creamer which displayed prominently "trans fats: zero grams" with a checkmark. Its ingredients are in order: "corn syrup solids, vegetable oil (partially hydrogenated coconut or palm kernel..." (you can view the nutritional information here) According to Wikipedia's article on trans fats, the partially hydrogenated oils are pure trans fats. The serving size is 1 teaspoon, and 225 servings per container. So am I right that this product is basically extremely high in trans fats and that they are exploiting a loophole by making their serving size so small that they are (apparently) allowed to list this as "zero grams of trans fats" obviously intending to give the impression that the product itself has none? If I'm correct, how can this type of deceptive practice be legal? (I'm being a bit rhetorical asking about legality, I know the answer: lobbying). But it's infuriating. 68.237.2.254 (talk) 00:28, 8 November 2008 (UTC)

The Coffee-mate FAQ [1] says the amount of partially hydrogenated oil is "trivial" and meets FDA guidelines for allowing the product to be identified as trans-fat free. Dragons flight (talk) 00:37, 8 November 2008 (UTC)

This is an officially endorsed rounding "error." If it's less than 0.5 grams, it's recorded as zero. It's why Diet Coke has 0 calories instead of 1: the food labeling regulations say to round by 5's. See 21 CFR 101.9. Giving a more exact value is deceptive for most food products, because variations in the raw materials (milk from cow to cow can have different fat content) and variations in manufacturing processes between production plants will give uncertainty. The serving size issue is rather a thorny one, and is the subject of some rancor. The regulatory question is: Is one teaspoon a reasonable amount for a single "serving" of the food? Labeling it as zero is correct from a regulatory standpoint if it is. As for whether the advertisement is illegal, ask a lawyer (preferably one who knows something about 21 USC), because "labeling" (as defined) is a very grey area. SDY (talk) 01:04, 8 November 2008 (UTC)

As you say, it's probably correct from a regulatory standpoint, but it's also clearly misleading. There is a big difference between something being absent and something being present in a quantity below your ability to accurately measure. Advertising laws seem to be very inconsistent in what they consider to be false advertising... --Tango (talk) 01:25, 8 November 2008 (UTC)

There's a difference between things that are illegal and things that are prosecuted. When someone's driving 150 mph in a 20 mph school zone and the next guy behind him is going 25 mph, they've both broken the law, but only one of them is likely to get prosecuted. The advertisement may very well be illegal. SDY (talk) 01:55, 8 November 2008 (UTC)

Deceptive advertising isn't likely a legal issue; it's not a crime in any real sense. It is a violation of regulations, and companies that advertise deceptively can be brought up on civil charges, but probably not criminal ones... --Jayron32.talk.contribs 02:19, 8 November 2008 (UTC)

It's all the same. By violating a regulation (in the US), you are violating the law that the regulation is based on. If you look at a book of the CFR, it'll give an "Authority" (look at the bottom of the page) citation to an actual law (USC = United States Code). When you get to court, you have to prove that the law was broken, you're not actually convicting them on regulations. That they broke the regulation is prima facie evidence that they broke the law, but that doesn't mean they can't argue the point. Civil law has different standards ("Preponderance of the evidence" rather than "beyond a reasonable doubt" for level of proof required) and other quirks but it's still the same legal process. For the record, I am not a lawyer and definitely not speaking for anyone but for my own demented delusions. SDY (talk) 02:28, 8 November 2008 (UTC)

Most deceptive advertising issues in the US are actually handled by the FTC. Only in the event of disputes over FTC judgments would the matter generally be referred to a court at all. The FTC Act, the law governing deceptive advertising, gives the FTC the ability to pursue civil judgments payable to the US government in the event that an advertiser defies FTC orders. Dragons flight (talk) 02:36, 8 November 2008 (UTC)

Hmm. I think I may refer this over to another reference desk, since it's very non-science at this point. SDY (talk) 02:47, 8 November 2008 (UTC)

The thing is, it's almost impossible to guarantee something is absent. For example, in most Western countries we expect all food to be melanime-free but in reality there is an allowed limit. So basically if you say something is absent or a product is free of something, all you are really saying is it's below some limit (for many reasons including the difficulty in testing below that limit, the accuracy of the tests etc). If you don't agree with this, then you are basically saying you don't agree anything should be labelled free or something being absent. If this is your POV, then you are entitled to it, but I'm not convinced it's a view shared by many. Of course, one of the problems is many people don't understand science, and therefore don't realise it's not usually possible to say something is absent with certainty, so you could argue it's only fair that using such terms is banned. Now as to whether the set limit for trans-fats is the right limit, that's a completely different issue. Nil Einne (talk) 08:12, 8 November 2008 (UTC)

I think the key point is that this appears to be an absolute limit, rather than a relative one. A relative limit can be justified in the way you say, there is no justification for an absolute limit in an arbitrary serving size. --Tango (talk) 14:27, 8 November 2008 (UTC)

Sorry I may have misunderstood what's being discussed here. Are you saying that if I sell pure transfat if I can justify having a serving size pf 0.5g or less then I can label the product as transfat free? And that in particular, this product actually has a very high percentage of transfat? If so the I agree it's misleading advertising and although I could be wrong, I'm not convinced it would be acceptable here in NZ. Having said that, I agree with 128 below that while it's misleading, I wouldn't personally be extremely concerned about transfat from something like creamer which for most people is probably not going to add a great amount to your diet. Nil Einne (talk) 12:41, 9 November 2008 (UTC)

That's how I understood what people above were saying. I could be wrong. --Tango (talk) 21:33, 9 November 2008 (UTC)

Aha! I have found this: document (pdf). A "trivial" amount indeed. You use one tablespoon of this stuff (I probably [heretofore] used more than that in one cup) you've got about half of the recommended limit for trans fats in a day (emphasis on limit; none is better). I appreciate the discussion of legality, but I stated in my OP I wasn't really questioning that. As I said, lobbying has secured this type of bullshit carveout. So they're operating within the bounds of the law. That does not reduce their ethical depravity, nor render this any less a deceptive practice.--68.237.2.254 (talk) 10:44, 8 November 2008 (UTC)

There is a problem with this - there is no "recommended limit" for trans fat in the US. The actual recommendation is "as close to none as possible". The 2-g limit comes from a UN recommendation of 1% of total daily calories so for an average 2000 calorie diet, you get the 2 gram number. However, there is suspicion that this 1% figure was merely plucked out of a hat with no scientific backing.[2] The U.S. FDA specifically says that "While scientific reports have confirmed the relationship between trans fat and an increased risk of CHD, none has recommended an amount of trans fat that FDA could use to establish a Daily Value (DV)."[3] Rmhermen (talk) 15:26, 8 November 2008 (UTC)

I'm not quite sure where in the article Trans Fat you got the impression that partially hydrogenated oils are pure trans fats. That is simply not the case. Partially hydrogenated oils are usually a mix of trans unsaturated fatty acids, cis (regular) unsaturated fatty acids and saturated fatty acids. Only a portion of even pure partially hydrogenated fats would be actual trans fats. Furthermore, under Trans_fat#United_States, it discusses the labeling regulations: "However, unlike in many other countries, trans fat levels of less than 0.5 grams per serving can be listed as 0 grams trans fat on the food label." This practice might be a little misleading, because, as you mention, items with a very small serving size may contain an above-average fraction of trans fats, yet still be under the 0.5 g cutoff due to their small size. On the other hand, you probably won't be eating large amounts of foods with small serving sizes, so the total contribution to your diet will still be small. -- 128.104.112.72 (talk) 18:44, 8 November 2008 (UTC)

FDA labelling standards allows Sodium Saccharine to say that it contains "no sodium," since there is less than 1 gram per serving. Edison (talk) 02:56, 11 November 2008 (UTC)

non-flammable comprimise gas mixture for an airship

Hydrogen is flammable, but it lifts very well. Helium isn't flammable, but it doesn't lift as well. What if you were to mix the two gases in a proportion that still allowed for buoyancy, but wasn't flammable? Would this work? Would the gases separate? Would the benefit of increased buoyancy be enough to justify it? Are there any other problems that I'm missing, because it seems to me like a perfect solution to the problem with airships. If this would work, I kinda doubt I was the first to think of it.63.245.152.13 (talk) 02:14, 8 November 2008 (UTC)

Helium is twice as heavy as hydrogen but actually lifts nearly as well in air, because it's the difference to the far heavier air that matters. See Lifting gas#Hydrogen and helium. The main drawback of helium is not lower lift but higher price, especially in the golden era of airships. PrimeHunter (talk) 02:27, 8 November 2008 (UTC)

I've heard that hydrogen, although flammable wouldn't actually be all that bad in airships with proper safety considerations despite the Hindeburg. Hydrogen won't burn without oxygen, but it will ignite readily in a wide range of oxygen proportions. The main issues would be keeping oxygen out, and keeping any escaped hydrogen which is mixed in with regular air from igniting and then compromising the structural integrity of whatever is storing the hydrogen. You may be interested in Hydrogen safety. 152.16.15.23 (talk) 03:17, 8 November 2008 (UTC)

Mixing in helium doesn't really help - it's excluding oxygen that really matters. You don't want the ratio of oxygen to hydrogen to get anywhere close to an explosive mixture. But all that matters is the ratio - after all, hydrogen and oxygen explode even when four fifths of the air is Nitrogen - which in this context is almost as inert as helium. The nitrogen (or helium) simply doesn't matter - it's not involved. It's widely agreed that modern hydrogen balloons could be made very safe - but the negative publicity of the Hindenberg is hard to recover from. FWIW - an amazing number of people survived the Hindenberg because the hydrogen was moving rapidly upwards and away from the gondola when it burned. The material that the envelope was made from (a variant of thermite - which is a pretty good explosive) was a major part of the problem. With modern plastics keeping the oxygen out - monitoring equipment to tell us that there is a problem - safer materials that don't make sparks...and an increasingly dire shortage of helium...we're going to go back to hydrogen balloons - it's just a matter of time. SteveBaker (talk) 03:46, 8 November 2008 (UTC)

The lower explosive limit for hydrogen gas in air is about 4%; that is, a mixture with air that contains at least 4% hydrogen gas will burn. In other words, creating a mix of hydrogen with helium that will be dilute enough not to be flammable means using a mixture that's going to be essentially pure helium anyway. For the extra percent or two of lifting capability it probably wouldn't be worth the extra cost and complexity of mixing gas. TenOfAllTrades(talk) 16:22, 8 November 2008 (UTC)

Putting 4% hydrogen in with your helium would only gain you about half a percent more lift. --Carnildo (talk) 23:08, 10 November 2008 (UTC)

cement production on other planets

Modern civilization is apparently very dependent on cement. I really can't imagine how the modern world would be what it is without it. The thing is, cement is produced from limestone which is produced from biological processes on Earth. In the future, when we colonize other previously lifeless planets, there will surely be lots of rock there, but none of it will be limestone. Limestoneis just calcium carbonate, though. That seems like a pretty simple chemical formula and calcium and carbon are fairly abundant too. So wouldn't it be possible to synthesize lime from non-biological ingredients on a planet with no limestone? Wouldn't it just involve bonding calcium and carbon? Also, how would you go about getting these elements from rocks on other planets? 63.245.152.13 (talk) 02:41, 8 November 2008 (UTC)

There are chemical processes that can produce limestone as well as biological ones. For example, any solution with a sufficiently high pH, high calcium ion presense, and exposure to CO₂ will likely precipitate calcium carbonate (i.e. limestone). Calcite, the basic component of limestone, can be found in Carbonatite, which is essentially igneous marble. The material in cement, quicklime or calcium oxide (or its hydrate known as slaked lime) could be derived from nearly any calcium-rich mineral. It is derived from limestone on earth because it is abundant; but any planet with similar calcium reserves as earth will likely contain compounds which would suffice. --Jayron32.talk.contribs 03:00, 8 November 2008 (UTC)

Actually lime is another name for compounds that are predominantly CaO. CaO is quite common in minerals, but usually only at the ~10% level with Si, Al, or Fe oxides being more prominent. Given enough energy you could extract lime from a wide variety of source materials, but on Earth limestone (CaCO3) is preferred due to the relative ease of processing. Dragons flight (talk) 03:00, 8 November 2008 (UTC)

I wouldn't rule out the presence of calcium carbonate on a planet devoid of carbon based life. The mineral calcite is calcium carbonate and can and does have inorganic origins (although a lot of calcite is in limestone a lot of which is organically originated). Check calcite for more info. 152.16.15.23 (talk) 03:02, 8 November 2008 (UTC)

If you collect water from the polar zone of the moon, you can make cement by adding it to random lunar dust, which has been dehydrated by extreme heat, per the analysis of lunar soil returned by the Apollo expeditions. Edison (talk) 04:54, 8 November 2008 (UTC)

But the idea of colonization of other planets does not exist outside science fiction books. Otolemur crassicaudatus (talk) 08:53, 8 November 2008 (UTC)

At one point walking on the moon only existed in science fiction books. So did heavier than air flight. I could go on. You are correct that at this point in history planetary colonization is fictional, I doubt it will be for long. I fail to see how it matters at all. We're going to have to think about things like this some day. 63.245.144.68 (talk) 13:37, 8 November 2008 (UTC)

I hope you will receive the Nobel Prize next year. Otolemur crassicaudatus (talk) 13:44, 8 November 2008 (UTC)

Why the sarcasm? What did I say?63.245.144.68 (talk) 13:56, 8 November 2008 (UTC)

Not at all. The idea exists in plenty of serious plans written by space agencies and academics. Sure, it hasn't actually been done yet, but it is far more than just fiction. --Tango (talk) 14:20, 8 November 2008 (UTC)

There are always some people within the scientific community who love crackpot ideas, but that does not make them real. There are people who believe some creatures from a distant planet will someday send them a message. Otolemur crassicaudatus (talk) 15:03, 8 November 2008 (UTC)

You think the people running NASA are a bunch of crackpots? They have serious plans to build a lunar colony (well, permanently manned base, at least, I don't know how you define "colony") within the next 10-20 years, as do other space agencies. As for SETI, I think everyone knows it's a long shot, but they think it's worth it - personally, I agree with them. A little time with a radio telescope in exchange for possibly discovering conclusive proof that we're not alone in the universe is worth it. --Tango (talk) 17:04, 8 November 2008 (UTC)

If you redefine everyone who disagrees with you as a crackpot, then everyone who isn't a crackpot will agree with you! APL (talk) 19:15, 8 November 2008 (UTC)

OK, yeah. I see what's going on here now. I suppose you're one of these people who think global warming and evolution are crackpot theories too? Cute. :) 63.245.144.68 (talk) 19:17, 8 November 2008 (UTC)

WHAT MADE YOU BELIEVE I THINK GLOBAL WARMING AND EVOLUTION ARE CRAKPOT THEORIES? Global warming and evolution are proved facts employing scientific method. Extraterrestrial colony is not only practically impossible, it is theoretically impossible also. Otolemur crassicaudatus (talk) 19:51, 8 November 2008 (UTC)

In my experience, people who believe in one pseudoscientific idea tend to beleive in others. I see no reason why establishing colonies on other planets is impossible. 63.245.144.68 (talk) 20:42, 8 November 2008 (UTC)

There's no need to shout. Could you specific which widely accepted theory contradicts the possibility of extra-terrestrial colonies? --Tango (talk) 20:51, 8 November 2008 (UTC)

• First of all, let assume that it is possible to make a base in any other planet. But in that case, the cost for production of the cement (scientific research + cost to maintain a permanent base in the planet + the cost of transportation to earth) will be so high that it will be absurd to use it for commercial purpose on Earth. The International Space Station costs approximately $100 billion while a ton of cement for commercial purpose on Earth costs only $20 (in regard to Thailand).
• Second, in this case we are certainly talking about terrestrial planets since human landing and staying is impossible in gas giants. So the planets we have are Mercury, Venus and Mars. Mercury does not have atmosphere and its surface temperature of Mercury is 442.5 K. So it is impossible to stay in Mercury. Venus has dense atmosphere and the temperature and atmospheric pressure of Venus makes it inhabitable also. The only terrestrial planet close to earth is Mars. See the article Colonization of Mars. It is unknown whether Martian gravity can support human life in the long term. Otolemur crassicaudatus (talk) 21:47, 8 November 2008 (UTC)

"Unknown" is a far cry from "theoretically impossible". I don't think anyone was suggesting exporting the cement to Earth, the idea is to make the cement you need to build the colony locally rather than importing it from Earth at great expense. If you want to make a commercially viable colony you'll need something you can export or a service you can provide (tourism might get you started, but it wouldn't get you very far, astronomy might be good, if someone gets fusion reactors working He-3 might be a valuable export, rocket fuel and servicing for people travelling further afield, although it will be some time before that's useful). In short, a we're a long way off commercially viable colonies, but publicly funded bases are seriously planned and should be around in a few decades (I suspect NASA's estimate is a little optimistic, there are sure to be budget cuts before then that will push it back, there always are, but they or someone else will get there eventually). --Tango (talk) 22:16, 8 November 2008 (UTC)

Why not think about building a distilled water plant in solar core? Are you suggesting these "colonies" in other planets will really serve any purpose on earth (any economic purpose)? Where will you build the colonies - on Venus? On mercury? As I have said above, it i impossible to build base in these two planet. Again see Colonization of Mars#Concerns, "There is likely to be little economic return from the colonization of Mars". Otolemur crassicaudatus (talk) 22:34, 8 November 2008 (UTC)

And again you cannot ignore the gravity issue. Otolemur crassicaudatus (talk) 22:40, 8 November 2008 (UTC)

If you can cover your setup costs somehow (upfront payments by colonists, maybe, if you can get the costs down far enough) you only need sufficient income from exports, etc. to cover the costs of importing the few things you can't make locally. Mars could serve as a base for asteroid mining - I believe it's possible to get raw materials from asteroids to LEO for similar, if not lower, costs than from Earth, they could then be used for building orbital habitats, etc. Mars could also serve as a stepping stone towards the outer solar system, although missions to the outer solar system would probably be primarily scientific. I'm not saying any of this will happen quickly, I don't expect to see any significant population on Mars in my lifetime (I'd hope we send a few people there, though) - the Moon and LEO, maybe. However, it not being commercially viable is very different from it not being theoretically possible, which is what you claimed. Give it 100 years or so, and there may well be sufficient activity in space to make such colonies commercially viable (you're familiar with the quote, "I think there is a world market for maybe five computers"? (I know it's probably apocryphal, but that's not the point) It is very difficult to predict what there will and won't be a market for in the future). --Tango (talk) 23:11, 8 November 2008 (UTC)

Also, you seem to rule out the possibility of ever colonizing anything outside our solar system. I know that leaving this solar system is probably WAYYYYY off, but I'm sure it will be done someday if we last long enough. To me, whether a colony is commercially viable or not doesn't seem to be as important as if it's self-sustaining. Being able to make money off of space colonies will be important, but for some people, establishing a colony on another world would be enough incentive. 63.245.144.68 (talk) 10:28, 9 November 2008 (UTC)

There are massive difficulties involved in colonising other solar systems, the most likely method is generational ships which would need to be truly self-sustaining over 100s or 1000s of years. For a nearby colony you only need to be reasonably self-sustaining and can import a little every now and then to make up for losses, that requires some kind of export to pay for. The setup costs of making a fully self-sustaining colony would probably be so great that you could just invest the extra cash on Earth and use the profits to pay for the imports with plenty to spare. --Tango (talk) 14:15, 9 November 2008 (UTC)

Figuring out how to make concrete on the Moon and Mars is solving the wron problem. We only use concrete here on earth because it's cheap and available. It has lots of horrible problems...it's only reliable in compression - in tension it's positively fragile - it's heavy - it takes vast amounts of energy to produce...all kinds of issues. On another planet, there will be other materials that are cheap and which have other strengths and weaknesses. Who knows? Artificial diamond might be the way to go - or foamed aluminium - it's going to be a matter of fitting in to what we have. So the idea of doing whatever it takes to make concrete is not entirely reasonable. On the moon, we know that the 'sand' particles are very sharp and spikey - and they interlock in interesting ways that the rounded, smooth sand grains here on earth cannot. Using that property of Lunar sand might be the way forward rather than wondering how to process lunar sand to be more like earth sand so we can make earthlike materials. SteveBaker (talk) 17:57, 10 November 2008 (UTC)

An excellent point. There is an argument for sticking with what you know, though. We know all about how to build with concrete, what its limits are, how best to reinforce it, etc., etc.. It may not be worth going through that learning process again with some new building material just because it is slightly easier to make locally. (If it's a lot easier, then it probably would be worth it.) --Tango (talk) 18:01, 10 November 2008 (UTC)

How could thoughtful people of the 15th century possibly assert that colonies in the New World will provide any possible benefit for Europe? They would have had to be a Crotalus horridus to make such a claim. Edison (talk) 02:59, 11 November 2008 (UTC)

Komodo Dragons in North America

Back in the 90s, the local zoo had a few young komodo dragons. This was before they knew that the females could lay eggs without mating. Anyway, let's say if society were to collapse and all the animals in zoos got out, would komodo dragons be able to survive in North America (specifically, I'm in Kansas)? It would only take one female to start a self-perpetuating population, though the population would be almost entirely homogeneous being descended form only one individual. They're tropical reptiles, but would they adapt to a cooler climate? I know monitor lizards can burrow, so couldn't they just curl up in a hole in winter? 63.245.152.13 (talk) 02:50, 8 November 2008 (UTC)

While someone else could tackle the rest of the question, I doubt that the komodo dragons used to a tropical climate are going to be intelligent enough to develop a new behavior like digging a hole. As an example, some lemurs living in North Carolina don't realize that leaving their tails out of their enclosure's heatbox would cause them to get frostbite and require amputation. Their stubby tails are sad to look at but they don't understand that it can actually get that cold because it never gets cool enough in native Madagascar. The situation for a Komodo dragon may be similar in that it would realize it was cold and try to seek somewhere warm, but wouldn't realize that trying to bask outside in the middle of Kansas winter even in the daylight isn't going to heat it up enough. Also keep in mind that any parthenogenic offspring of the female will be male so for perpetuation of the population one of the sons needs to mate with its mother to produce more females. 152.16.15.23 (talk) 04:01, 8 November 2008 (UTC)

Kinda disappointing... I was hoping that when the economy finally crashes and everything goes to hell, I could make a suit of armor and go save little rural farming villages from the local dragon.

If we were talking about florida on the other hand, I would give the komodo dragons a fighting chance. Reticulated pythons have managed to squeeze into the everglades quite nicely. I've heard iguanas are or have already formed some small isolated populations too. 152.16.15.23 (talk) 22:29, 8 November 2008 (UTC)

OK, well, what if a mad scientist genetically engineered...just kidding. :) 63.245.152.13 (talk) 04:38, 8 November 2008 (UTC)

But then again, if there was a large enough original population, couldn't natural selection take over? The lizards with the most cold resistance would survive each winter and after a few decades, they'd have adapted. You know how evolution works. I'd think this would be kind of unlikely with only one female and her parthenogenic offspring, but if several of them escaped....

As you can tell, I really want to live out my childhood fantasies! :D 63.245.152.13 (talk) 04:42, 8 November 2008 (UTC)

Natural selection will not save an ectotherm from a hostile environment. In fact, if it was introduced, the cold would simply eliminate the Komodos in favor of the indigenous species, because it has no adaptations to the cold. bibliomaniac15 04:44, 8 November 2008 (UTC)

I am rooting for them to survive and prosper in the eventuality hypothesized. Why not? Humans survived inhospitable circumstances. Edison (talk) 04:52, 8 November 2008 (UTC)

Aside from the cold problem, what suitable prey foods might Kansas offer that Komodo dragons would be able to catch and swallow? —Preceding unsigned comment added by CBHA (talk • contribs) 05:05, 8 November 2008 (UTC)

Komodo dragons would probably hunt deer, wild turkeys, and other larger animals, as well as scavenging available carrion. Whatever it can ambush is fair game. bibliomaniac15 05:14, 8 November 2008 (UTC)

The Komodo dragon may encounter other problems in Kansas. The diet section of the article Komodo dragon talks about the interesting race-against-time problem encountered by a Komodo dragon that has swallowed a goat (or similar size animal.) They have to digest the meat before it putrefies and poisons them. In a cooler climate than Komodo Island, this may be less of a problem. Or more.

The cooler climate will slow down metabolism and digestion. This may necessitate smaller prey items. 152.16.15.23 (talk) 22:25, 8 November 2008 (UTC)

Also, in Kansas, the virulent bacterial population of the Komodo dragon's mouth (also discussed in the article) would probably be vastly different. The impression I get from the article is that the bacteria are an essential part of the Komodo dragon's "ecology".

IMO, this question cries out for an experimental approach. I wonder whether the Kansas Department of Wildlife and Parks would approve test stocking of Komodo dragons. Aside from the "contribution to scientific knowledge" aspect, this might lead to some unusual and exciting hunting opportunities, especially if Kansas gets a program in place before Nebraska moves in. CBHA (talk) 06:12, 8 November 2008 (UTC)

That was AFTER humans had developed sufficient intelligence which allowed them to survive a large multitude of environments. If you suddenly dump a species in a completely hostile environment, there's a very good chance it's not going to survive. Remember, when we have catastrophic events which lead to a significant change in the environment, we also tend to get mass extinctions. Some species survive the changing environment, but many don't. And while many species have migrated, often they don't migrate to a massively different environment, at least in one go and as far as we know. Even if they do, most species (or genera) who live in a wide multitude of environments appear to have adaptions which enable them to survive resonably okay in these multitide of environments, which therefore likely arose before they were so far widespread. Nil Einne (talk) 07:30, 8 November 2008 (UTC)

Reptiles in temperate or cold climates usually find places to hibernate in winter. Reptiles seem to be pretty widespread, so it stands to reason that at some point komodo dragons had an ancestor that lived in a much cooler climate and therefore had the instinct to hibernate in the winter. Wouldn't it be possible that that latent hibernation instinct could be revived with a bit of natural selection or perhaps just the right stimulus? What we really need to be asking is, how do tropical reptiles usually respond to a cold climate?

Also, half the reason I love the Wikipedia reference desk is because you take insane questions like this seriously. This place kicks ass. :D 63.245.144.68 (talk) 13:27, 8 November 2008 (UTC)

I agree! 152.16.15.23 (talk) 22:25, 8 November 2008 (UTC)

I just learned from the humanities desk that I'm descended from the gods. 63.245.144.68 (talk) 05:18, 13 November 2008 (UTC)

If the mama Komodo dragon found a dry storage site for nuclear waste, where the spent fuel was in stainless steel casks, or even in pools, enough heat would be emitted to keep her quite cozy (without being exposed to a lethal level of radiation). She could live long and prosper. The Wolf Creek Nuclear Generating Station in Burlington, Kansas has 427.3 metric tons of spent nuclear fuel in storage per [4]. This also sounds like the start of a fine 1950's black and white horror movie about mutant Komodo Dragons. Edison (talk) 03:07, 11 November 2008 (UTC)

Relativity's contradiction

Respected sir/ma'am,

I have read special theory of relativity from halliday,resnick and walker's fundamental of physics.After reading that I came across a doubt which my teacher told me that it is contradiction to relativity.But I cannot find contradiction anywhere.

(wrt is with respect to) Question is :-

Suppose 2 observers A and B ,A is at rest wrt ground and B is moving at comparable velocity

v/c doesn't tend to 0.Now if A observe B time for B wrt A increases.But other way round if B

observe A time for A wrt B increases.So time is increasing for both wrt to each other and

they should be of same age for any time interval which doesn't happen.

Pls tell me how to get this logic is right or wrong.

Thanking You! Yours obediently, Harsh Agarwal(harshagg) —Preceding unsigned comment added by Harshagg (talk • contribs) 09:27, 8 November 2008 (UTC)

You are correct - from the viewpoint of each observer, time is passing more slowly for the other observer. This appears to create a paradox if you are still thinking in terms of a Newtonian absolute time. However, in special relativity, neither observer has a privileged viewpoint, and the fact that they each observe time to be passing more slowly for the other observer simply means that their local time co-ordinate axes are at an angle to each other. The apparent difference in time can become a real difference in elapsed time if the observers meet up at some point in the future in the same frame of reference. But to do this, one observer has to accelerate, their histories are no longer interchangeable, and so their viewpoints are no longer symmetrical - see our article on the twin paradox. Gandalf61 (talk) 09:51, 8 November 2008 (UTC)

Gandalf is absolutely right. I think the part you are missing is that, as Gandalf61 says, one of the observers has to accelerate in order for them to end up again at the same point, while the other doesn't. Hence things are not symmetrical, which makes all the difference. Also, you don't have to word your question in the "application" form they teach us in India in fifth standard lol (just kidding, I'm from India too) ReluctantPhilosopher (talk) 10:07, 8 November 2008 (UTC)

What if A and B mirror each other and accelerate at the same rate so as to arrive at a common point? What then? Clarityfiend (talk) 03:04, 9 November 2008 (UTC)

If they reach a common point but still have a non-zero velocity relative to each other then they still have different frames of reference, so there is no paradox. If one observer accelerates so as to reduce their relative velocity to zero then the accelerating observer experiences a real time dilation as per general relativity, so there is a real difference in elapsed time, but no paradox as their histories are not interchangeable. If the observers achieve a zero relative velocity by both accelerating in a symmetrical fashion then they both experience identical time dilation and there is no difference in elapsed time, so once again no paradox. Gandalf61 (talk) 10:24, 9 November 2008 (UTC)

A few questions about immunology

Hello, I would be very grateful if somebody could help me understand four questions about the immune system:

1. Is adaptive immunity acquired even if an infection is treated with antibiotics, or is it necessary for the body to eliminate the pathogens itself?
2. Is it true that adaptive immunity cannot be acquired against UTIs caused by Escherichia coli, since it is not in the body's "interest" to create defences against a bacterium which is important for the gut?
3. If somebody develops immunity against one certain species of bacteria, does that help in any measure against other, related species of bacteria?
4. Lacking an adaptive immune system, does that mean that lampreys are vulnerable to the same pathogens time and again?

Thank you! -Leptictidium (mt) 09:36, 8 November 2008 (UTC)

---

• 1 probab ly yes, because the antibitiocs will have been given well after the start of the infection giving the system plenty of time to respond.
• 2 I think that immunity will not normally be triggered against "food".
• 3 yes if the related bacteria present the same antigens on their surface, but closely related bacteria can appear very different. Graeme Bartlett (talk) 11:43, 8 November 2008 (UTC)

You might find this an interesting read for point number 4. They act like they have an adaptive immune system by responding to infections more rapidly second time around. I'm not sure how this works though, I didn't read the whole article. —Cyclonenim (talk · contribs · email) 12:10, 8 November 2008 (UTC)

---

• 1. Many antibiotics are "bacteriostatic". These antibiotics don't actually kill bacteria, but simply prevent them from growing more. For these antibiotics, the immune system is pretty much essential to eliminate bacteria that are already present; the antibiotics mainly give the immune system a chance to get ahead of the infection.

Other antibiotics are "bacteriocidal", and actually kill bacteria. Even with these antibiotics, it's difficult to treat patients with severe immune defects, though.

• 2. This isn't true. Immune responses to E. coli are common, and fortunately so, because there are several pathogenic strains of E. coli (as well as the commensal strains that are normally present).

However, immune responses to organisms on the surfaces of the body (including the skin and the mucosal lining of the urinary tract, as well as the inside of the gut) are special cases in general. It's not in the body's interests to generate massive immune responses in these areas, because it's normal to have some microbes there (or to have vast numbers of microbes there in the case of the gut). If there was a constant immune response to organisms on our surfaces, our surfaces would be constantly inflamed. There are special forms of adaptive immunity that are specialized for mucosal surfaces, and these will work on urinary E. coli (as well as on pathogens in the gut, and so on). The issue of mucosal surfaces is much more important than the "bacterium that is important in the gut" issue.

• 3. The previous answer (yes if the related bacteria present the same antigens on their surface, but closely related bacteria can appear very different) is exactly correct.

• 4. Lampreys do have an adaptive response, though it is quite different from jawed vertebrates in the molecular details. As such, they do have a memory response to pathogens, though it's slower and perhaps less effective than in jawed vertebrates.

Non-vertebrates do not have adaptive immune responses, and these species are indeed vulnerable to the same pathogens time and again. (It's not quite so simple, because there's evidence that exposure to a pathogen can trigger a general, relatively long-lasting, state of increased immune responsiveness in some insects, so if the insect is exposed to the same, or a different, pathogen in that period it will be more resistant. There are also some claims that some insects may have an adaptive immune response ,wit ha true memory component, though these are rather unconvincing, in my opinion.)

Hope this is helpful. Ian (talk) 17:23, 8 November 2008 (UTC)

So what causes the corn to pop?

Having just read the explanatory responses to the cell-phone/corn popping advert above, I have a little problem understanding how the corn is 'popped'. I do understand why corn pops in normal cooking circumstances. Richard Avery (talk) 10:08, 8 November 2008 (UTC)

Water inside the kernel, coupled with a strong outer shell; water turns to steam inside and can't escape until it builds up enough pressure to cause a mini-explosion. What advert? There's no intentional advertising on this site. You sure you didn't follow a link from an outside site?---68.237.2.254 (talk) 10:46, 8 November 2008 (UTC)

It was this question above about an advertisement. Fribbler (talk) 11:15, 8 November 2008 (UTC)

The popcorn in the cell-phone popping advert is popped by special effect. Somewhere on the internet is the un-edited video, but the jist of it is that already-popped pieces of popcorn are dropped onto a table near a pile of unpopped kernels. The popped kernels are air-brushed out until they hit the table. Once the popped kernels hit the table and bounce upwards, the unpopped kernels are airbrushed out. So it looks like the unpopped kernal has popped and jumped upwards slightly.

It's a rather clever bit of editing. APL (talk) 19:20, 8 November 2008 (UTC)

Found it. Here is a CNN interview with one of the guys who came up with this. Watch how he says it "wasn't about scaring people". Phone popcorn secrets revealed APL (talk) 19:31, 8 November 2008 (UTC)

Great, that simple, (well, if you have the gear) That would explain why some of the participants are looking up to the ceiling before the action gets under way. Many thanks APL. Richard Avery (talk) 19:53, 8 November 2008 (UTC)

Garden burial of animal remains enhances soil fertility?

Beyond the reputed benefits of decaying organic matter, is there anything special about the custom of burying animal remains in one's garden plot? My teenaged daughter cites this from Fried Green Tomatoes in response to a fairly urgent family issue: disposing of a mole's head deposited not far from our doorstep, apparently brought as a trophy/offering by our outdoor cats. I'm actually willing to do this if there's a valid reason. -- Thanks, Deborahjay (talk) 14:04, 8 November 2008 (UTC)

Ask the cat Deborah as it is his/her trophy. If the cat says 'yes' then bury it in your plot. Richard Avery (talk) 17:42, 8 November 2008 (UTC)

With the item remaining in situ for a good 24 hours, all four cats have since showed up as usual and utterly ignored it. I took their behavior as an indication there were no proprietary interests involved nor spirits to propitiate, hence no ceremonial disposition seems required or desired. We'll continue to rely on conventional fertilizing and composting.-- Deborahjay (talk) 18:16, 8 November 2008 (UTC)

opinion on those chairs you sit in with your legs folded under

unfortunately I don't know what to search on, maybe we have an article. How is it to sit in those chairs where your leg folds under you? Does it keep your back straighter, is it more ergonomic, better for long periods in front of a computer, etc? Or is it just a fashion/trend thing?

Obviously I'm NOT asking for legal, medical, or chiropractic advice! —Preceding unsigned comment added by 82.124.214.224 (talk) 15:56, 8 November 2008 (UTC)

I can't answer your question, but I'm assuming (just so everyone understands) that you're asking about kneeling chairs...? TenOfAllTrades(talk) 16:13, 8 November 2008 (UTC)

Yes. Anyone have an opinion on kneeling chairs? —Preceding unsigned comment added by 82.124.214.224 (talk) 16:20, 8 November 2008 (UTC)

Good for the back, but uncomfortable and not very good for the knees. If you are prone to back problems, get a kneeling chair and a conventional one, and switch frequently. Also go to a gym or pool to improve the overall muscle system holding up your back. --Stephan Schulz (talk) 17:08, 8 November 2008 (UTC)

I liked the one my brother used to have. Other than that, I don't have an opinion or reference. Dismas|^(talk) 18:39, 8 November 2008 (UTC)

I've never found one that gave enough room to my long feet. —Tamfang (talk) 03:13, 9 November 2008 (UTC)

Top Elo rating

Is there any theoretical maximal Elo rating in chess?--Mr.K. (talk) 19:03, 8 November 2008 (UTC)

As I understand it, there is no upper limit. The maximum rating is limited by the number of rated players and relative disparity in their skills. Gary Kasparov achieved the highest chess rating of 2851, but some other games using the Elo system have seen ratings over 3100.,

If someone appeared today that could beat modern grandmasters (of Elo 2700) 95% of the time, then the system would give them an Elo of ~3200. If someone then beat that player consistently (and everyone else essentially all the time) then they could get an Elo of 3700, etc. There may be practical limits to how dominating any one player can really be, but the system is open-ended so dominating performances can allow the Elo to climb essentially without limit. Dragons flight (talk) 19:25, 8 November 2008 (UTC)

OK, you could reach a perfect level of play - without any thinkable mistake - that could not be improved anymore...--Mr.K. (talk) 19:48, 8 November 2008 (UTC)

The problem is that the system isn't built upon number of wins, or even how "dominating" or "perfect" those wins are. The two factors involved are whether or not you win or lose, and the difference in ELO rating between you and your opponent. If the winner had a higher rating going into the game, his rating will not go up as much as if the loser had a higher rating going into the game. The rating is largely dependant on who you get to play moreso than how well you play... --Jayron32.talk.contribs 00:34, 9 November 2008 (UTC)

If ELO chess ratings of some players become too high then it may be decided to reduce them. I don't follow chess but remembered reading about Burmese players getting unreasonable high ratings years ago. See [5]. I don't know how it ended or whether this is a common problem. PrimeHunter (talk) 03:31, 9 November 2008 (UTC)

Sex in space

Have people ever had sex in space? Does it work any differently than on Earth? --76.91.56.34 (talk) 21:38, 8 November 2008 (UTC)

of course. people have even had a child! the first space kid. —Preceding unsigned comment added by 82.124.214.224 (talk) 21:43, 8 November 2008 (UTC)

See Sex in space. --Tango (talk) 21:45, 8 November 2008 (UTC)

Centrifuge

Why do heavier objects collect at the walls of a centrifuge? The article doesn't seem to explain why. Thanks! —Preceding unsigned comment added by 76.69.241.185 (talk) 22:45, 8 November 2008 (UTC)

Just as the force of gravity causes heavier- denser-than-water objects to sink (in water), the centrifugal force produced by a centrifuge causes the heavier denser material to drift away from the rotational axis. The advantage of a centrifuge is that, unlike gravity, we can control the centrifugal force by changing the rotational rate or radius of the centrifuge. Common centrifuges can produce forces thousands or 10's of thousands times the force of gravity. -- Tcncv (talk) 01:58, 9 November 2008 (UTC)

Here is an article that seems to have a good explanation. -- Tcncv (talk) 02:07, 9 November 2008 (UTC)

Commenting on Tcncv's reply: it should be denser-than-water & denser material, rather than heavier. BentzyCo (talk) 02:28, 9 November 2008 (UTC)

Good point. I stand corrected. Thank you. -- Tcncv (talk) 02:40, 9 November 2008 (UTC)

Proving evolution with drugs

Doesn't Antibiotic resistance prove evolution? 190.157.120.42 (talk) 23:06, 8 November 2008 (UTC)

yes. --Jayron32.talk.contribs 23:37, 8 November 2008 (UTC)

Just 'yes'? Great then, I just resolved the entire controversy. Spread the word! o_O 190.157.120.42 (talk) 23:59, 8 November 2008 (UTC)

You asked a binary question. If you are unsatisfied with the answer, perhaps you should consider phrasing it differently. --Jayron32.talk.contribs 00:08, 9 November 2008 (UTC)

There really is no doubt among anyone that knows what they're talking about. Evolution is the only plausible explanation for what we see around us. In fact, as your example shows, we know without doubt that evolution does happen, the only possible area of doubt is whether or not evolution is sufficient to explain the variety of species we observe. Studies seem to indicate that it is (there are gaps, but there's no reason to believe we won't fill them in sooner or later). --Tango (talk) 00:10, 9 November 2008 (UTC)

It unquestionably proves natural selection. It does not, IMHO, prove evolution. That would require fossil records. Magog the Ogre (talk) 01:25, 9 November 2008 (UTC)

Natural Selection is merely one of the many mechanisms in which evolution occurs. You don't need a fossil record to witness microbial evolution, since the generations occur on a time scale considerably shorter than the process of fossilization. It sounds like Magog the Ogre needs to read the Evolution article. -- JSBillings 02:13, 9 November 2008 (UTC)

No one seriously doubts that evolution exists. Creationists simply dispute that it is responsible for life as we know it. Breeding disease resistant plants exemplifies evolution but it does not prove that all life evolved from a primordial soup. Plasticup ^T/C 04:38, 9 November 2008 (UTC)

Evolution is proven already; I think what you're really asking is, "would a person who still doesn't believe in evolution, most likely for religious reasons, change their mind upon learning about antibiotic resistance in bacteria"? The answer is probably no, but it will depend on the person. (By "evolution" I mean whatever you meant by it—presumably the origin of species by natural selection, genetic drift, geographic isolation, etc.) -- BenRG (talk) 14:21, 9 November 2008 (UTC)

From the other point of view, the Creationists look at this and consider it "microevolution"—variation within a species, like dog breeding—and distinguish it from "macroevolution"—or actual speciation. Scientists do not generally make that distinction and do not see a hard line between the two concepts. --98.217.8.46 (talk) 15:12, 9 November 2008 (UTC)

I think it's fair to say that the Creationists were backed into their macro- vs. micro- distinction -- God of the gaps style -- when what they consider micro- became patently obvious even to non-scientific people. Presumably even the president of the Answers in Genesis group prefers modern antibiotics to older ones which have long since been overtaken by bacterial evolution. --Sean 15:01, 10 November 2008 (UTC)

A demonstration that I did a LONG time ago demonstrates what's going on. Cut out a few dozen paper squares - each maybe 2"x2". These are our animals. Now take a large pile of coins of random denominations (quarters, dimes, nickels, pennies) and put two onto each paper square animal representing it's genes - one coin on the left of the square, one on the right. (Actually - you don't need real coins - you can just write the values onto the paper instead). Now, play the following game:

• Genetic reproduction: Take pairs of animals at random - let them "make babies" (four babies per pair of parents) - two of the four offspring have coins identical to the left-coin from the 'daddy' animal and the right-coin from the 'mummy'. The other two have the same right-coin as the daddy and the left coin of the momma.
• All of the parents die off and their paper squares and coins are 'recycled'.
• Natural selection: Now - look at the new population of animals and sort them so the ones with the biggest cash value are on your left - ranging down to the ones with the least cash value on your right.
• Sadly, the cheapest ones die young - so eliminate (and 'recycle') the half of the population with the least cash value...the survivors become the parents for the next generation.
• Repeat the process several times.

After a very few generations, almost all of your animals have quarters or perhaps dimes in their genes - and after not many more generations, they are all 50 cent animals.

Interestingly - you can change the rules partway through - and the "environment" can change to suddenly benefit animals that which weigh the least. Because dimes and pennies weigh less than nickels and quarters, you soon get a population of 2c, 11c and 20c animals.

There are other interesting experiments you can do. Suppose that you start your population of animals with none of them having a quarter in their right-side gene. No matter how long you play the game, you'll never get any 50 cent animals...they'll pretty soon all be 35 cent creatures. Now - suppose that every generation, you introduce a mutation. Each generation, pick a couple of animals at random and for each one, replace one of it's "gene" coins with a different one (sometimes a quarter, sometimes a dime, etc). These mutants will mostly be worth less than 35 cents - so they'll get eliminated from the gene pool rather quickly - but once in a while, you'll get a freak mutation that creates an animal with a quarter in it's right gene. In an amazingly small number of generations, this freak will take over the world - and all of your animals will be 50 cent creatures.

SteveBaker (talk) 15:26, 10 November 2008 (UTC)

Any interesting demonstration, but not quite how genetics works, as I understand it. There is no distinction between right and left, they all get mixed up, so if the parents were AB and CD the 4 children should be AC, AD, BC and BD. To demonstrate the affects of mutation, start off with everyone having the same coin (a dime, say) on both sides, and then proceed with the generations as you describe with random mutations which can change dimes to any other coin and see how long it takes before almost everyone is worth 50 cents. --Tango (talk) 17:10, 11 November 2008 (UTC)