Wikipedia:Reference desk/Archives/Science/2008 September 2

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September 2

Solubility of Hydrocodone/Acetaminophen?

This question deals with possibly inappropriate use of controlled substances. Publishing an answer here would not be in the interests of Wikipedia or its readers. I have blanked this question, discussion here. Franamax (talk) 14:18, 2 September 2008 (UTC)

A similar question has been re-posted below, at Wikipedia:Reference desk/Science#Solvents_of_common_pharmaceuticals. -- Coneslayer (talk) 13:01, 3 September 2008 (UTC)

Word for a substance that makes you piss more?

Im pretty sure ive heard a word for substances that make you piss more, but i dont remember what it is. I believe caffeine is an example of such a substance. Anyone know what the word is? --212.120.246.239 (talk) 03:14, 2 September 2008 (UTC)

Diuretic. Dragons flight (talk) 03:17, 2 September 2008 (UTC)

Beer. (You don't buy it, you just rent it). Edison2 (talk) 02:52, 3 September 2008 (UTC)

Would they take it back after it has been uhh... utilised? --antilived^{T | C | G} 05:56, 3 September 2008 (UTC)

Yes. They then resell it as American "beer". DMacks (talk) 05:58, 3 September 2008 (UTC)

natural antibiotics?

I know there are several plants that are presumed to be "natural antibiotics", such as garlic. Is there any indication (journal articles) linking specific herbs with killing specific types of bacteria/viruses? Or it's all just "unproved naturopathy" Mathityahu (talk) 07:22, 2 September 2008 (UTC)

It's very much proven. Instead of pointing you to a specific reference regarding a specific compound (like diallyl disulfide, or better de:Diallyldisulfid Refs 29-35 in the case of garlic) where you should find in the Reference Section links to clinical studies and other papers, I will just mention that plants produce such chemicals because, not having an immune system, they need such stuff to fight the steady attack of microorganisms, see secondary metabolite (which is sadly inadequate). In fact, even your normal antiobiotic comes from other organisms that had to fight bacteria: penicillin is a product of a fungus, and why should there be a difference in the general evolution of plants/fungi, just as there is a plant defense against herbivory?

This does not mean you should abandon your doctor and treat yourself when you're ill. It also doesn't mean every plant antibiotic is suitable for human use, at all. Many fungal and bacterial antibiotics (yes bacteria against themselves) that were discovered have serious side effects, too. --Ayacop (talk) 10:12, 2 September 2008 (UTC)

Thanks for the links, very interesting. Are there any other "proven" herbs? Mathityahu (talk) 19:10, 2 September 2008 (UTC)

Not even one based on randomized-controlled trials. Scray (talk) 01:19, 3 September 2008 (UTC)

Depends on the compound. Myrtol (de:Myrtol) is a standardized terpene extract from Myrtis communis (a myrtle species), and well researched with sinusitis and bronchitis:

• H. Matthys et al.: Efficacy and tolerance of myrtol standardized in acute bronchitis - a multicentre, randomized, double-blind, placebo-controlled parallel group clinical trial vs. cefuroxime and ambroxol. Arneim.-Forsch./Drug Res. 50/-/2000 100-711.[Abstract auf Deutsch]
• R. Meister et al: Wirksamkeit und Verträglichkeit von Myrtol standardisiert bei der Langzeitbehandlung der chronischen Bronchitis - Eine placebokontrollierte Doppelblindstudie. Arzneim.-Forsch./Drug Res. 49/-/1999 S. 351-8 [Abstract]
• P. Federspil et al.: Wirkung von Myrtol standardisiert bei der Therapie der akuten Sinusitis - Ergebnisse einer doppelblinden randomisierten Multicenterstudie gegen Placebo. Laryngo-Rhino-Otol. 76/-/1997 S. 23-7. doi:10.1055/s-2007-997381

metabolic functions of proteins from human/mouse

I'm puzzled. Every major protein in the Wikipedia lists lots of functions in its infobox, and also most of the time, an analogous protein from animals, mostly from the mouse. Now, did they find out all those functions from looking at humans or at mice? Do we generally transfer results directly from mouse to human? Shouldn't mouse results labeled as such? Because if the mouse were such a good model, we wouldn't need clinical studies, would we? --Ayacop (talk) 10:27, 2 September 2008 (UTC)

Usually when you do genetic studies, you do them in a model organism, because it is exceedingly hard to get approval from an Institutional Review Board to do controlled crosses or make transgenics/knockouts with humans. Add to that the 10-20 year turn around for humans to reach sexual maturity, and such experiments on humans themselves become prohibitive. (Not to mention unethical.) To overcome these problems, researchers use model organisms. Mice and rats are usually used because they are mammals, easy to breed, have a (relatively) short life, and present less of an ethical/moral issue than, say, chimpanzees or dogs. For general information "protein X does Y", especially in a metabolic sense, the differences between mice and humans are vanishingly small. While we look vastly different, inside we're pretty darn close. In fact, a large amount of biochemical data has been first collected in yeast, flies or worms, and later been found to be applicable to humans. Now clinical studies are a different issue. When testing drugs small, seemingly innocuous changes, which may have no effect on the normal operation of the organism (such as single amino acid changes), can have a large effect on the efficacy of the drug. But note that there is usually a large body of model organism testing (usually on mice/rats) prior to the start of clinical trials - the in-human tests is to be doubly sure of the results. -- 128.104.112.147 (talk) 17:01, 2 September 2008 (UTC)

Much about real similarities/differences between mice and men is unknown, perhaps because such comparisons depend on difficult studies of rare humans that are homozygous for loss-of-function mutations. One recent example reveals a major difference between mice and humans: the TLR adapter protein MyD88 appears to be dispensible in humans for defense against viral infections and all but a few pyogenic bacterial infections. Scray (talk) 00:44, 3 September 2008 (UTC)

The history of the lab rat is actually pretty interesting. They were chosen originally because nobody cared about rats (in a fit of irony, someone had their house firebombed by zealous animal rights protesters not too long ago for doing research on lab rats), they have relatively short lifetimes (you can go through them pretty quick to see changes), they reproduce quickly, and because they were relatively easy to standardize (the Wistar rat was one of the first successful "branded" model organisms). These are qualities are are in general good for model organisms. Rats are particular useful for human-related research, as noted, because they are mammals along with all of the above reasons. There are, as noted, limitations, but it's a much better place to do a "first draft" of something than on other animals. --98.217.8.46 (talk) 02:21, 3 September 2008 (UTC)

Political parties and teenage pregnancies

How would I get information on whether, for the same socio-economic class, Democrats or Republicans had a larger proportion of teenage pregnancies? I'm wondering about the influence of differing views on topics such as sex education and abstinence-only beliefs.

Thanks! — Sam 12:03, 2 September 2008 (UTC)

The big problem here is that neither political alignment or teenage pregnancy status are statistics that are dependably tracked. The best you can hope for is a very small survey in a very small locality with a high rate of error. If you attempt to make a point using random statistics you find online, you will likely end up with a ridiculous point such as one I saw this past week... Rolla, MO has had a huge influx of frogs. In the last two years, more frog species are being discovered in Rolla than anywhere else in the world. Why are all the frogs suddenly being attracted to Rolla? ... That was taken from statistics showing a lot of frogs being identified in Rolla. Why? The local university started a class in biodiversity and one of the assignments is to locate and categorize frogs. So, in the last two years (since the class started), more frogs are being identified there than anywhere else. I hope that helps explain why you can't grab a statistic here and a statistic there and try to make some point about views on sex education. -- kainaw™ 12:16, 2 September 2008 (UTC)

Generic warnings aside, statisticians have developed many ways over the past, oh, 150 years or so to determine whether or not an effect is just due to bad data or whether it is real or not. The idea that the political ideology of the parents can have an effect on the rate of teenage pregnancy is not out of left field, given that political ideology and feelings about the running of a family have long been known to have been linked, and the issue of contraception is obviously key in that. A friend of mine who lived in a very rural, "red state" area reports that it was often the kids of hard-core fundamentalists who got knocked up in high school because they never learned about sex ed and were afraid to talk to their parents about it. That's an anecdote—and not statistically meaningful—but it does imply a mechanism; a hypothesis which could be tested. --98.217.8.46 (talk) 02:31, 3 September 2008 (UTC)

I don't know about Dems vs. Repubs, but there have been studies trying to determine whether sex-ed or abstinence-only is more effective at preventing teenage pregnancy. For example, this and this say that sex-ed is clearly superior at preventing teen pregnancy. (Incidentally, one of those reports notes that sex-ed also increases sexual activity, which of course some people view as unacceptable, even if that sex is safer.) Dragons flight (talk) 12:33, 2 September 2008 (UTC)

Here's a graph (of dubious origins, though the numerical data is legit) which seems to imply that states in which Republicans are in charge have higher teen pregnancy rates than states with Democrats in charge. That doesn't imply causation though—the same underlying reasons that put one party in charge could be behind the trend (e.g. poverty). So it doesn't mean much (other than indicating that the "Red states" hardly have any monopoly over "family values").

If it were me, I'd want to do a study looking at the politics of the parents (however measured—self-identified would be fine) of kids who get knocked up. I haven't been able to find anything like that, though. --98.217.8.46 (talk) 02:40, 3 September 2008 (UTC)

stripy babies

are lots of baby animals stripy? I know that tapirs have stripy babies to hide them in the dappled forest shade, but why would baby emus be stripy as they live on the plains? Bradley10 (talk) 12:42, 2 September 2008 (UTC)

Plains or not, stripes still help to camouflage an animal. The point isn't so much to "look like your surroundings," but instead to break up the shape of the animal. Likewise a tiger can be very well camouflaged in the jungle, even though that might be surprising to anyone who had seen his bright orange (not very jungle-y) skin. — Sam 13:41, 2 September 2008 (UTC) —Preceding unsigned comment added by 63.138.152.238 (talk)

Also, while it doesn't really apply in this case, zebras are also a plains animal that are very stripey.

Some zoologists believe that the stripes act as a camouflage mechanism. This is accomplished in several ways. First, the vertical striping helps the zebra hide in grass. While seeming absurd at first glance considering that grass is neither white nor black, it is supposed to be effective against the zebra's main predator, the lion, which is color blind. Theoretically a zebra standing still in tall grass may not be noticed at all by a lion. Additionally, since zebras are herd animals, the stripes may help to confuse predators - a number of zebras standing or moving close together may appear as one large animal, making it more difficult for the lion to pick out any single zebra to attack. A herd of zebras scattering to avoid a predator will also represent to that predator a confused mass of vertical stripes travelling in multiple directions making it difficult for the predator to track an individual visually as it separates from its herdmates, although biologists have never observed lions appearing confused by zebra stripes.

-- MacAddct  1984 ^{(talk • contribs)} 13:54, 2 September 2008 (UTC)

It's a popular misconception that camouflage is most effective by making an animal look like the surroundings. Instead most "blending in" is caused by disruption of the shape of the animal. The brain does most of the work of camouflage—if we don't see something that looks like an animal, we don't see it at all. --98.217.8.46 (talk) 23:26, 2 September 2008 (UTC)

• It's also a popular misconception that mammals other than humans do not perceive color. Lions do have color vision, but not as good as ours. However, the term "color-blind" is fair since it is also used for humans whose color vision is not as good as most. --Anon, 06:10 UTC, September 3, 2008.

Wartime camouflage of ships is an example of disrupting the outline. Through a submarine periscope it may be possible to know something is there, but whether it is two or more ships seen in an overlapping view, or ships following each other, or just one ship, may not be clear. This type of camouflage has been called "dazzle painting". Camouflage uniforms, I think, have an outline-disruption effect combined with a blend-in effect. This combined effect has also been used on military vehicles, artillery barrels, tank-gun barrels, and on small arms. Andme2 (talk) 01:39, 3 September 2008 (UTC)

Do the hurricanes have anything to do with global warming?

I've been wondering lately about these hurricanes and cyclones that we hear about all the time in recent years (Katrina, Cyclone Nargis in Burma, and now Gustav). Is there any science that points to these being somehow the result of global warming? It seems to me that they are worse than they used to be, but that might just be confirmation bias screwing with my head. Are they worse than they used to be? More frequent? (I guess the sample size is pretty small, even if they are more frequent it could just be a conincidence).

By the way, I don't have a political agenda here, I'm really just curious, and I haven't heard anyone explain it properly to me. 83.250.202.36 (talk) 14:54, 2 September 2008 (UTC)

I have no idea of the science but the articles Effects of global warming and this part in particular (Effects_of_global_warming#Effects_on_weather) consider the effect that global-warming has on 'extreme weather'. I suspect you will suffer a bit of bias - I think the term is something like time-memory bias or something silly ilke that (look for article list of biases) - essentially the recent past may seem larger/more important in your mind than the distant past, even if both events were of equal size. 194.221.133.226 (talk) 15:15, 2 September 2008 (UTC)

I'm no expert, but I think it's extremely tricky to try to point to a single cause of a hurricane. One thing we know- many of these storms feed on warmth- see Warm core. So, if there are higher air or water temperatures in the areas that have them, I think this will tend to lead to increased storm activity. It's all very complex and unpredictable though - a general trend of bigger storms doesn't mean any particular hurricane season will be bigger. Friday (talk) 15:20, 2 September 2008 (UTC)

Note in the warm core link above that warm water is only half of the story. You need high-level condensation - so you need cooler air on top. If the water is warmer and the air is warmer, it won't help much. If the water is warmer and the air is cooler, you get more power out of the warm core. As for hurricanes, the frequency and strength have not had any significant increase. Much more powerful storms existed in the past and they came in both greater and fewer numbers, varying from year to year. In the recent past (15-20 years), two big changes happened. First, we have a huge number of people moving to the southeast coast so the population of people expecting to be hit is increased. Second, we have multiple 24-hour weather news services letting us know every minor detail of every storm. Combined, we know a hell of a lot more about more storms that are doing more financial damage. -- kainaw™ 15:56, 2 September 2008 (UTC)

The articles mentioned above are all good sources of science, and are most neutral. Check out the top editors of the articles, and you might also post your question to their user talk pages, and they'll point you in the right direction. Always read the citations and/or sources for anything in any Wikipedia article, so that you can dig deeper in the topic. OrangeMarlin ^{Talk• Contributions} 16:18, 2 September 2008 (UTC)

I finally found a rather unbiased graph of the number of hurricanes per year. This one actually counts tropical storms, not just hurricanes. It shows the slight upwards trend in frequency that has been attributed by many sources as a normal cycle between high frequency and low frequency. It does not show the hockey-stick curve projected by alarmists. Also, you can see the most expensive hurricanes in List of costliest Atlantic hurricanes. Ensure you look at the lower table where costs are adjusted for inflation. -- kainaw™ 16:50, 2 September 2008 (UTC)

Um. I don't want to nitpick. But Institute for Creation Research is probably not who I would put my faith in (yuk yuk) for unbiased research. --98.217.8.46 (talk) 01:48, 3 September 2008 (UTC)

I believe that most researchers are claiming that the increase in the NUMBER of hurricanes is too small to be statistically relevent - but the increase in the ferocity of them is a clear trend. Sadly, I don't have a reference for that. (Er...it might be in "An Inconvenient Truth"...I'm not sure.) SteveBaker (talk) 04:03, 3 September 2008 (UTC)

I'm yet another person with unconfirmed uncited information. After Katrina I heard another chemist (not trained in atmospheric science) conjecture "More violent storms seem to be an expected result of global warming. Putting more energy into the system means there is more energy to knock around." She might be wrong maybe maybe global warming means more moisture in the air which will slow storms down but her reasoning rings true to my training and experiencec. But Kainaw also has a point with his "a tree makes no sound if no one is there to hear it" comment.--OMCV (talk) 04:13, 3 September 2008 (UTC)

While I don't agree with the ICR as being unbiased... I used that specific graph because it was unbiased. In fact, I found that it was particularly unbiased by including tropical storms - many of which went to hurricane strength in the past but by rule weren't counted as hurricanes if they died down before making it to shore. In modern times, if a storm becomes a hurricane in the middle of the Atlantic and then dies out, we count it as a hurricane. So, you will usually find graphs showing a particularly high increase in hurricanes due primarily to the method used to identify them as such - not because there are more of them. As for the ferocity of the hurricanes, I added the list of the worst hurricanes to show that the recent ones are not necessarily more violent than past ones. We just put more importance on recent ones. -- kainaw™ 23:50, 3 September 2008 (UTC)

(making this small because it is terribly off topic) And a point on a completely different topic... I am sure there are many who will read my comments and walk away thinking that I don't believe that global warming exists and, therefore, I am a strong supporter of GW and I love my guns and I go to church every day to gripe about how we should bomb all the brown people in the world. Just because I see evidence that the hurricanes are not necessarily occurring in greater numbers or evidence that they are not stronger does not have anything to do with my opinion on global warming - which I wish was not called global warming. It is a terrible problem that most people do not comprehend and, as a result, make rash ignorant decisions about. Just this morning, I was in the elevator and overheard a doctor (obviously educated) tell another doctor that he is looking for jobs in Michigan because global warming is going to flood out the entire coast soon and he doesn't want to live underwater. -- kainaw™ 23:55, 3 September 2008 (UTC)

This new study (doesn't seem to be on Nature's website yet) suggests that the frequency of strong hurricanes has increased in the last 25 years, while the frequency of weak hurricanes has remained fairly constant. Algebraist 00:02, 4 September 2008 (UTC)

That is not new news. There was a well documented lull in hurricanes during the 70's and 80's. So, if you look in the last 25 years, you'll see increase in hurricane activity. If you look at the last 100 years, the increase is there, but it isn't very significant. It is possible that we should still be in a lull but global warming took us out of it early. It is also possible that a 15-year lull was normal and we are returning to a normal level. It is possible that both are true. It is possible that neither are true. I am not claiming that global warming is not affecting hurricanes. I am only claiming that it is very easy to look at the number of storms over the last 100 years and the years in which the most powerful hurricanes occurred and you can see that it is hard to claim global warming took a few baby storms and turned them into dozens of killers. -- kainaw™ 00:29, 4 September 2008 (UTC)

Hurricane question

Is it possible for two hurricanes to collide or would they repel each other? Thanks, Alex--AlexSuricata (talk) 17:24, 2 September 2008 (UTC)

See Fujiwhara effect. They can get close and circle one another, but not truly collide or merge. -- kainaw™ 17:31, 2 September 2008 (UTC)

Of note -- our article claims that they will eventually merge if they don't separate. I've always heard it explained that one storm will weaken the other to the point that it goes away, leaving only the stronger of the two. So, it is up to you to decide if that means they collided and merged. -- kainaw™ 17:32, 2 September 2008 (UTC)

Great, thanks! --AlexSuricata (talk) 23:56, 2 September 2008 (UTC)

Blindness

Can people who have been blind from birth dream or picture things in their minds eye ? —Preceding unsigned comment added by 80.5.198.130 (talk) 18:38, 2 September 2008 (UTC)

I seem to recall that it depends on the cause of blindness. Many blind people can see things in their mind's eye because they have complete visual faculties in their brain but there's something wrong in how their eyes work. I'm not sure they experience it the same way that sighted people (or people who have seen at least once) do, but they are capable of thinking visually and having intuitive understanding of visual metaphors. I suspect they dream as well.

If they are blind because the visual faculty of their brain is seriously impaired, then I suspect not so much. But I don't remember.

This is from a Cognitive Science class I took maybe 6 or 7 years ago so it's not exactly the most reliable information, but I remember it being something that I found interesting at the time. --98.217.8.46 (talk) 01:46, 3 September 2008 (UTC)

Blindsight makes interesting reading in that regard. SteveBaker (talk) 03:51, 3 September 2008 (UTC)

Yeah blindsight is neato, but the opposite, Anton-Babinski syndrome is even weirder, especially in the context of the question.

To the OP: there's really no way to say. The fact is, if someone has been blind from birth, they would simply lack the vocabulary to articulate visual experiences if they had them. Moreover, any attempt to determine empirically (i.e. externally) if they're having visual experience would be meaningless. For instance, imagine an fMRI study was performed to see if V1 (a region of the brain that is believed to be necessary for conscience visual perception, largely due to research on blindsight) is active in congenitally blind individuals. Even if it was shown that this area is active, that doesn't mean they are experiencing visual percepts. The brain is a very plastic organ, and regions that go unused for their normal function are often appropriated by nearby regions. In other words, every brain is different, and people who are born with anatomical or perceptual abnormalities can be expected to have different cerebral organizations than the norm, making the kind of experiment I suggested difficult if not impossible to implement.

So the short version is even if congenitally blind folks have visual experiences, they don't know it because they don't know what visual experiences look like/are (literally), and we don't know it because we have no useful way of accessing their potential visual experience. You'd find the article Mary's room an interesting read. --Shaggorama (talk) 04:42, 3 September 2008 (UTC)

Air-water experiment

This is about a simple experiment which can be considered as a thought experiment or could actually be performed. (This is not a homework assignment, just a question I dreamt up.)

The experiment requires a closed container full of air at atmospheric pressure, and another container of hot water. The closed container has a gauge that measures the difference in pressure between the inside and the outside of the container.

The container is quickly opened and some water is "instantaneously" injected. The water displaces a volume of air equal to the volume of water. Then the container is quickly closed and shaken vigourously, bringing air and water to the same temperature. As the air is heated in the process, it expands increasing the pressure in the container.

Suppose the container volume is V, the initial air temperature is TA, the initial water temperature is TW, and the volume of water injected is VW.

TW is greater than TA, and VW is less than or equal to V.

If VW is zero, the pressure will NOT increase because no hot water is injected. If VW equals V, the pressure will NOT increase because all the air is displaced and none is left to expand.

The tentative conclusion is that somewhere between VW = 0 and VW = V there is a volume of water that will cause the maximum pressure rise.

What ratio of VW/V will give the largest pressure rise? Does this answer depend on the temperatures of the air and the water? Are there other factors that need to be known to work this out?

Wanderer57 (talk) 20:33, 2 September 2008 (UTC)

Water has pressure too, unfortunately for this experiment. Someguy1221 (talk) 20:53, 2 September 2008 (UTC)

Thanks. Unfortunately I'm not clear from this whether Someguy1221 is saying that the experiment makes no sense at all or that the answer is complicated by the hydraulic head of water inside the container (or none of the above). Please will someone give me a less cryptic answer? Wanderer57 (talk) 00:20, 3 September 2008 (UTC)

The water may contain dissolved oxygen and other gases. The shaking may release these gases, which will complicate the experiment. Everyone knows what happens when you open a can of Coke after it has been shaken. But unexpected factors are why an experiment has to be repeated many times, by many people, in many places, and with the same results, before confidence can be placed on the conclusions provided. Even then, "scientific facts" may eventually be shown wrong because the results were misinterpreted by many scientists, or hidden factors were not seen. Yesterday's truth may become today's falsehood. Andme2 (talk)01:10, 3 September 2008 (UTC)

You might want to look up stuff on thermodynamic cycles. To figure out your ideal ratio you are going to have to define most of the other unknowns, for example what is the temperature ratio you describe. In addition the ideal gas laws will not account for the fluids vapor pressure or the fluids ability to dissolve gases (henry's law) both of which are temperature dependent. Basically you need to define things until the only unknown is VW/V. Even then using all these formula just gives a ballpark answer. The best way to determine the ideal ratio would be empirically.--OMCV (talk) 01:30, 3 September 2008 (UTC)

I think Wanderer's question is interesting, so let's start with a theoretical question and then account for the two minor effects later. The theoretical question uses an ideal gas to replace the air, and it uses an "ideal liquid" to replace the water. The liquid is incompressible adn contains no disolves gasses, and the ideal gase does not disolve in the liquid. furthermore, the liquid's volume does not change with temperature. The liquid has a heat capacity of one BTU per pint per degree Farenheit across the entire relevant temperature range. -Arch dude (talk) 01:35, 3 September 2008 (UTC)

Arch dude I think all you need is the gases heat capacity and the temperature ratio (in Kelvin) and the question can be reduced to a complex algebra or simple calculus problem. It would probably be best to use SI units rather than BTU and pints since its easier to convert units. Along these same lines heat capacity and the slightly different specific heat are usually given in (energy)*(mass)^-1*(temp unit)^-1, mass rather than volume since volume is expected to change with temperature while mass does not. It also important to remember that the ideal gas law requires temps in Kelvin making the difference between room temp ~295 K and boiling water at 1 atm 373.15 K smaller then reporting it in other temp units.--OMCV (talk) 03:47, 3 September 2008 (UTC)

What was the point of rubbishing Arch dude's choice of units if you are not then going to actually give an answer in your chosen units? You only need to make conversion easier if you intend to actually convert something. SpinningSpark 22:16, 3 September 2008 (UTC)

I was expecting my units to be laughed at-- that was just a bit of humor, and I happen to knoe the BTU/pint relationshiop for water without looking it up. On sober(?) reflection, our "ideal fluid" must have zero vapor presure, and this one wuill propably not be a minor effect. However, I also do not think we need any math to answer the question. My reasoning is as follows: except for the special case of 0 gas, the pressure is independent of the amount of gas and depends only on the temperature. Since more gas causes more cooling of the overall system, the highest pressure will occur with the smallest amount of gas.I this small-but-nonzero amount of gas has a negligible cooling effect, so the pressure is affected solely by the difference between the original gas temperature andthe water temperature. -Arch dude (talk) 23:57, 4 September 2008 (UTC)

But won't the liquid still have a vapour pressure regardless of whether there is any air in the container? You could take a container already full of water VW=V and add heat by means of a blowtorch - it will eventually explode, won't it? If you slap a pressure gauge on it, the gauge will go up. Franamax (talk) 03:23, 3 September 2008 (UTC)

cellulose

How does cellulose contribute to the cell wall? —Preceding unsigned comment added by 76.18.248.143 (talk) 21:02, 2 September 2008 (UTC)

Have you read cell wall? Specifically, The composition section answers your question. Someguy1221 (talk) 21:13, 2 September 2008 (UTC)

Genes for Skin

Approximately how many genes make up the appearance/type of our human skin including the color? —Preceding unsigned comment added by 70.136.156.69 (talk) 21:39, 2 September 2008 (UTC)

More than a few. Check out Human skin color#Genetics of Skin Color Variation for info on a few of em. --Shaggorama (talk) 04:17, 3 September 2008 (UTC)

What kind of moth?!?!

I have searched but i cannot find what kind of moth, (if it even is a moth,) this is. I found in a public laundry room in Northwest Louisiana. If anyone knows it would awesome to know! Thanks ahead of time for any time taken to find out what kind it is. Nick910 (talk) 21:45, 2 September 2008 (UTC)

Looks like male Eacles imperialis to me. --Dr Dima (talk) 01:53, 3 September 2008 (UTC)

Thanks much Dr. Dima!.Nick910 (talk) 17:48, 4 September 2008 (UTC)

Poppy Seeds

I understand that opium can be extracted from poppy seeds. I was in the store today, saw a 60g container of poppy seeds, and couldn't help but wonder how much opium that could produce (though I'd imagine it's not very much at all). In light of a recent question, I'll be perfectly clear that I have no intention to refine opium, and my questions stems purely from curiosity. Thanks!--El aprendelenguas (talk) 22:37, 2 September 2008 (UTC)

According to this page [1], the alkaloid content of poppy seeds is about 50 parts per million, which cannot have any pharmaceutical effect. DuncanHill (talk) 22:41, 2 September 2008 (UTC)

So does that mean that out of 60g of poppy seeds you could hypothetically extract 3mg of alkaloids, of which about 360 micrograms of which would be morphine? Which would be an incredibly uneconomical way to go about producing opium. (I'm dubious it would work, anyway, since my understanding of opium production is that you need the entire unripe seed pod, and many of them, to produce even just a little bit of the stuff. I'm suspicious that the dried seeds alone could produce anything.) --98.217.8.46 (talk) 23:23, 2 September 2008 (UTC)

Man, where did I read about the guy who ended up in intensive care after he bought several pounds of poppy seeds, boiled them, mashed them up, then shot the mush into his arm with a large bore needle several times, under the mistaken assumption that poppy seeds = opium? It was reasonably recent too. --Kurt Shaped Box (talk) 23:29, 2 September 2008 (UTC)

That was one of our most senior adminstrators. He had a bad day. He's fine now, except for the swollen arm. ...... (that's a joke, eh. ;o) Wanderer57 (talk) 00:27, 3 September 2008 (UTC)

There are many species and subspecies of poppy. As DuncanHill has indicated, the species that provides opium is Papaver somniferum — opium is derived from the latex of this species. The latex is obtained by making slits in the seed pod; this allows the latex to ooze out for collection. Refer to Papaveraceae and Opium poppy in Wikipedia. Andme2 (talk) 00:46, 3 September 2008 (UTC)

I read an article once about a guy who was a baker at a prison, who bought pounds of poppy seeds per day and made a tea or some such extract from it and managed to scratch the opium itch. There was another story about a bus load of Army recruits most of whom failed the drug test when they arrived for basic training, and it turned out it was because they had the poppy seed sandwich, but I do not recall the outcome. Edison2 (talk) 01:31, 3 September 2008 (UTC)

Now that has reminded me of a similar story about athletics officials. They were being shewn some new dope-testing kit which they had bought for a major competition. As part of the demonstration, some of the officials were invited to provide a sample - which they then failed. They had had a continental breakfast, with poppy-seed rolls that day. DuncanHill (talk) 09:50, 3 September 2008 (UTC)

The problem with poppy seeds nowadays is that globalisation leads to other varieties than the low-content ones being used, and other harvesting methods used in a small number of imports. This has led german authorities in a study to propose limits for import of poppy seed, which is heavily used in eastern Germany/Europe for desserts (the poppy plant is the national flower of Republic of Poland BTW, presumably for culinary reasons). Ref: [2] --Ayacop (talk) 07:19, 4 September 2008 (UTC)

Just in case someone thinks this is an urban legend, see this: "snopes.com: Poppy Seed Drug Test Results". Retrieved 2008-09-04.. When I was in grad school, I had a friend who had access to the greenhouse for the university. He did an experiment to see what percentage of poppy seeds would germinate (they're supposed to be sterilized, I believe, to prevent this), and, as I recall, some small percentage (1 or 2%) would germinate. And of course, there's the pharmaceutical company in the midwest that owned farmland to grow poppies for extracting the alkaloids to be purified into morphines (this was before they learned to chemically synthesize it). The field is adjacent to the research headquarters of the company, and occasionally poppies will start to bloom, and they quickly eradicate it. OrangeMarlin ^{Talk• Contributions} 14:49, 4 September 2008 (UTC)