Wikipedia:Reference desk/Archives/Science/2012 September 14

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September 14

Removing color from/clarifying orange juice

I know it doesn't make much sense, but I am trying to make a clear green drink that contains a decent amount of orange juice. Using yellow 5 and blue 1 I can get the right color of green, but it is darker than I would like, presumably because of the orange color in the base. Diluting the juice to 10% also does nothing to eliminate the opacity - I would prefer it to be clear. Even if it stays orange-colored, I think I can fix it with food coloring as long as it is clear. Pulp-free orange juice just clogs up a coffee filter, and I'm not really sure what else to try to clear it up. Any ideas? 108.194.140.240 (talk) 02:00, 14 September 2012 (UTC)

Have you tried to use orange extract instead of juice? --Jayron32 02:05, 14 September 2012 (UTC)

I've found a few answers to my own question, after realizing I hadn't thought to use "clarifying" as a keyword until I wrote here. I'll have to look into extracts, and see what I think of them. I just found some suggestions to mix in a small amount of gelatin powder, freeze, and let it thaw through a strainer. The other option I've seen that is apparently used by some chefs is to use a centrifuge - but I don't have access to anything like that. I won't mark this resolved just yet, maybe someone else will have some ideas or experience with this. 108.194.140.240 (talk) 02:15, 14 September 2012 (UTC)

Both of the techniques you note sound a lot like Molecular gastronomy which has been all the rage among the avant garde fringe of the culinary world for the past few years. --Jayron32 02:23, 14 September 2012 (UTC)

I think this may boil down (sorry:) to what you mean by "contains orange juice", or more specifically what your intended result (rather than method to getting it) is. For example, taking orange juice and trying to clarify it (remove the suspended and emulsified...whatevers) is one of many ways of getting to a clear liquid that tastes like orange. DMacks (talk) 02:42, 14 September 2012 (UTC)

I just found this [[1]], and also someone in the comments mentions that pectinase works on OJ. Pectinase means I can just stir and refrigerate, which is easier than any other method out there. I think I've seen enough ideas to be happy with them. Sorry I bothered the reference desk - I just was doing a bad job searching until after I posted! 108.194.140.240 (talk) 03:06, 14 September 2012 (UTC)

Resolved

Pointless referencing in science articles

Whilst at University, the first thing we were told was not to reference wikipedia, but to use the journals. And wikipedia editors are somewhat insistent on journal references.

I wonder how many realise how much those journal entries cost a member of the public to view and who is taking the cash.

And I wonder how many editors are aware that some of the big name distributors now don't even offer public accounts. I believe Science Direct is one such group. What possible use could a list of $25 to $35 a view entries, inaccessible to the public, be to the public? To access the evidence, one must give up a week or twos worth of wages to check the references. — Preceding unsigned comment added by 86.150.236.65 (talk) 02:30, 14 September 2012 (UTC)

If you wish to check the references to Journals which cost a lot of money, Wikipedia offers a service where someone with a subscription will check them for you, for free, and provide you with a copy or with relevent info as you need. See WP:REX. --Jayron32 02:39, 14 September 2012 (UTC)

The abstracts are usually free, so you can at least get a sense of what the article is about and some of the the main conclusions. That might be enough to see whether the cited statement is already supported (or sounds likely enough that you don't need to check the nitty-gritty details) without having to spend money. Or at least help you decide which of the many cited refs you actually do want to check in detail. DMacks (talk) 02:45, 14 September 2012 (UTC)

• The reason we require references is to validate the material in the articles. It is nice if the references are easily accessible, but that isn't the essential thing. We actually don't require that references be available online at all -- many book references are not. Looie496 (talk) 03:44, 14 September 2012 (UTC)

In addition, the full text of papers accepted for publication since April 2008 and supported by funds from the U.S. National Institutes of Health are, as a rule, freely accessible to the public under the NIH Public Access Policy. -- Scray (talk) 04:17, 14 September 2012 (UTC)

• In Australia, many university libraries allow visitors to access their online journals if they log on in person at the library. The Western Australian library service provides online access from home to thousands of textbooks via eBook Library. --Anthonyhcole (talk) 04:18, 14 September 2012 (UTC)

I guess I'm not really adding much, but an inaccessible reference is better than no reference. The situation with availability online is changing, because most of the research is supported by universities, and they know they are getting gipped if they have to pay again for access to knowledge they probably funded in the first place. Even for my PhD, I much prefer refs that are available full text online, as a courtesy to others, and because I hate having to bother logging in. I think most people do the same, but not all knowledge is freely available. IBE (talk) 05:07, 14 September 2012 (UTC)

I agree. Whenever two sources are equally reliable but one is free, I always cite the free one. --Anthonyhcole (talk) 05:15, 14 September 2012 (UTC)

Unless the free one is a direct, verbatim copy of the other, the better action may be to cite them both. More source material is always more better. --Jayron32 05:17, 14 September 2012 (UTC)

There is really no problem getting access to articles, and no reason not to cite almost any orginal source as a reference. In Western Australia, if you are a student, you can get almost anything journal-wise for free, though I assume if you abuse the privilige by say requesting lots of papers on the sexual perversions of eskimos when you are an engineering student, you may be spoken to. As Anthonyhcole has said, Universities allow free access to all printed journals held, and most online journals they subscribe to, to any member of the public who visits in person. If you are a member of your local (shire) library, you can ask them to email you a scan of anything held by any public or university library in Australia. That includes just about anything - I have succesfully obtained articles that appeared in Russian journals. The only downside is that the service is very slow, typically taking several weeks. But the service is completely free! Anyone in Australia can request almost anything from the Australian National Libray - they can, via the US Library of Congress and the British Library access anything, and the service is very fast - 2 days or so. But they charge about the same as commercial services. Ratbone120.145.29.139 (talk) 11:05, 14 September 2012 (UTC)

The thing is, Wikipedia could be set up to have articles that are no more than a list of references - no text whatever. But we don't - and the reason is that most people can't/don't-want-to get a hold of all of those referenced documents and read them all. The entire point of an encyclopedia is to provide a useful distillation of all of those core documents. You shouldn't reference Wikipedia because a better reference will always be to the things that Wikipedia references...but that doesn't make Wikipedia useless - very often you only need a summary and a reasonable presumption that the summary really does match the references it points to. But if it's a critical matter - then you're just going to have to get those source documents - no matter the cost or difficulty.

You ask whether Wikipedia editors are aware of this - and since they presumably had to read the referenced articles first before they could choose them to back up facts in the article, I'd have to say "Yes". Your underlying question is presumably something like: "Why don't we simply shun references that are costly/difficult to read?" - but if we didn't do that, then you wouldn't even be able to find our "summary" information for a large fraction of human knowledge...and you wouldn't know when (or where) to go with large piles of cash to find out whatever is missing. So it's important that we reference those documents - especially when they are hard to find or expensive to read. SteveBaker (talk) 13:12, 14 September 2012 (UTC)

The researchers who produce the journal articles are aware of it, and they're unhappy, too. Paul (Stansifer) 14:55, 14 September 2012 (UTC)

Dihydrogen vs. dihydrido

Can dihydrogen and dihydrido complexes be considered true tautomers? Plasmic Physics (talk) 06:31, 14 September 2012 (UTC)

Probably not, except by extension of the definition in some way. A true tautomer is almost always an organic compound that has two stable forms that are seperated by a low energy barrier, almost always involving the migration of a hydrogen atom and the shifting of a pi-bond. The kind of isomerism you note 1) doesn't involve organic compounds 2) doesn't involve the same sort of hydrogen atom shifting and 3) doesn't involve the movement of a pi bond. Rather, I think the better term for this may be Resonance in the sense that there aren't two forms of the complex (which is what tautomerism would imply: that there were two distinct forms actually found), but rather the difference between drawing the "Dihydrogen" model and the "dihydro" model doesn't represent a real difference, rather more a shortcoming in the lewis diagram model. --Jayron32 12:50, 14 September 2012 (UTC)

From what I gather, the article on dihydrogen complexes indicate that they are distinct with a low energy barrier. Plasmic Physics (talk) 13:28, 14 September 2012 (UTC)

Fine then, they are, but it still isn't tautomerism, which describes a specific type of single proton transfer within a specific set of molecules. Metal-ligand coordination complexes are not the right sort of molecules, and the way in which hydrogen "moves" is not the right sort of movement. Other than "involves hydrogen in some way", there's nothing about the reaction you describe which qualifies it as "tautomerism". --Jayron32 14:10, 14 September 2012 (UTC)

Then what kind of isomers are they? Plasmic Physics (talk) 06:18, 15 September 2012 (UTC)

The best term may be Linkage isomerism, since the hydrogen is bonded to the metal differently in each case. It's a odd type of linkage isomerism, to be sure, because dihydrogen is a bit of an odd ligand, being that the only electrons availible for bonding are those of the H-H sigma bond; most ligands don't bond via their own sigma bonds. But generally, if the only difference is in how the ligand is bonded, its a form of linkage isomerism. --Jayron32 04:32, 16 September 2012 (UTC)

Entropy of a fan

Let's say we have a fan connected to an electric motor. The motor is switched on, and work is performed on the fan. Does the entropy of just the fan increase or decrease as a result of the motor being activated? Why?

I'm curious because, as I understand it, entropy is defined as heat flow divided by absolute temperature. Here, though, we have energy transferred from the motor to the fan in the form of work, not heat. I think.

(You may be able to tell that I've never studied physics formally.) 75.60.184.181 (talk) 14:03, 14 September 2012 (UTC)

Friction converts work to heat, though. --Jayron32 14:04, 14 September 2012 (UTC)

Thanks. So heat is transferred from the fan to the surrounding air? I thought that might be the answer, but then I wondered what would happen if the temperature of the air were greater than the temperature of the fan. How could heat then flow from the fan to the air? 75.60.184.181 (talk) 14:26, 14 September 2012 (UTC)

Friction always increases the ambient temperature of what is being, well, frictioned (is that even a word? I don't know, but go with me on this). That is, whatever tempertaure it was before, the temperature will always increase as a result of friction because friction adds heat to the surroundings. So, the ambient temperature of the air and the fan is unimportant to the role of friction: friction warms the fan up, regardless of what its prior temperature was, and it will continue to do so until the relative temperature of the fan is greater than the air, at which point the heat will begin to transfer to the air. --Jayron32 14:30, 14 September 2012 (UTC)

The word is "fricked". μηδείς (talk) 16:43, 14 September 2012 (UTC)

I see. Am I correct, then, that the entropy of the fan will begin to decrease once it begins to transfer heat to its surroundings? Also, during the time between the activation of the motor and the point at which the fan's temperature overtakes the air's temperature, is there any entropy change? Thanks for your help. 75.60.184.181 (talk) 14:46, 14 September 2012 (UTC)

Entropy is a property of the system, not of its components, per se, unless they themselves can be isolated as a system, which a fan in an atmosphere cannot. Most of the increased entropy will be seen as an increase in air temperature, but there will also be some small wear to the fan's mechanism. If the outside air is simply hotter than the fan, the fan itself will eventually reach the same temperature, at which time its friction (internal and with the air on the blades) will start heating the air around it. μηδείς (talk) 16:48, 14 September 2012 (UTC)

Thanks Medeis. Well, I still don't quite understand, and I think I should hit the books again because I don't seem to understand the math well enough. But Medeis, do I understand you correctly as saying that entropy is only defined for isolated systems, that is, systems with essentially no exchange of matter or energy with the surroundings? I'm confused, because entropy change is defined in classical thermodynamics as $\mathrm {d} S={\frac {\delta Q}{T}}$, which I thought related entropy change to the heat absorbed by a (necessarily non-isolated) system. 75.49.2.198 (talk) 19:43, 14 September 2012 (UTC)

Obviously there is no such thing as a truly isolated system except for the universe. But the fan and the local air body (in a room, let's say) can be treated as an isolated system, while the functioning fan cannot be. The issue with the fan is, how would you naturally treat its entropy separately from the air in which it functions? Heat will be radiated into the air from the motor casing, conducted away due to the air passing over the body, and caused by the friction of the blades on the air itself. The wind from the blades will start as coherent motion, but degenerate quickly into environmental heat. There is no way to treat of this as regards the fan itself without taking the properties of the atmosphere around it into consideration. The entropy will go into the environment, not "stay" in the fan. But a fan in outer space will behave quite differently, heating up significantly itself, and radiating away but not conducting away heat (if one can say "conducting away"). As for the math, I am biologer by science training, so you may do better asking for a physicist. I did quite well in physics and chemistry, but by intuition, not hard math. I won't be one to explain or lead you to the right equations. μηδείς (talk) 21:12, 14 September 2012 (UTC)

Octopus reproductive process

I was reading our article on the Octopus and it described how the reproductive process was generally fatal to the octopus, but that researchers had managed to subvert it by removing the optic glands. I had a couple quick questions about this: Is this process invariably fatal, whether for the male or the female, and how would removing the optic glands subvert this process? Kansan (talk) 15:33, 14 September 2012 (UTC)

As far as I can tell, yes, reproduction invariably leads to death soon after, for both males and females. This is the life-history strategy of (all?) octopods, known as semelparity (sometimes called monocarpy). All annual plants are monocarpic, and many perennials as well. In animals, more famous examples of semelparity are salmon. Basically, the selective pressures on organisms can shape their reproductive strategies in many different ways, and this is the one that worked out for octopods. You may also enjoy this paper on octopus senescence here [2]. I didn't read the paper about removal of optic glands, but the abstract indicates that removal also resulted in "cessation of broodiness," which I think means that, though they returned to eating and surviving after spawning, they did not necessarily successfully reproduce. SemanticMantis (talk) 15:55, 14 September 2012 (UTC)

The fatality of reproduction in semelparous organisms is related to the fact that they have a breeding season, and that the likelihood of them living long enough to breed again within that second season is too low to be worth saving energy from the first breeding system to make the attempt. If octopuses could breed at any time, it might make sense for them to have smaller broods and live longer lives. But they have only a breeding season within which to reproduce. Hence, if they forgo reproduction now, they have to be sure to live until the next season, or have watsed their reproductive potential. Since they are softbodied organisms with high mortality rates, taking that risk makes little sense. It is better for them to put everything into the reproductive chance they do have now, rather than risking it on a later season that may never come. See the tradeoff section of semelparity. μηδείς (talk) 21:28, 14 September 2012 (UTC)

Thank you (both of you); I had also been wondering how that could possibly be an evolutionary advantage and that also answers that question. Kansan (talk) 22:27, 14 September 2012 (UTC)

I realized a while back (which is to say, not Wikipediable material) that the journey of the salmon from the big wide ocean upstream to a relatively small spawning area and their subsequent death and eventual decay into the local ecology is a way of the parents to pass on nutrients which they have accumulated in the ocean to their as yet unborn offspring, albeit pretty indirectly; see also the tendency of various female organisms to consume the male after fertilization, etc. Evolution be a harsh mistress.Gzuckier (talk) 03:36, 17 September 2012 (UTC)

What are these "optic glands", and what kinds of animals have them? (Wikipedia currently has no article for optic gland.) Does removing the optic glands blind the octopus? (That's rather depressing... imagine telling an octopus, "after you have sex, to live, you must be blinded".) Does removing the optical glands also physically remove the eyes, or do their eyes remain afterward, but just sit uselessly in their heads? —SeekingAnswers (reply) 22:36, 14 September 2012 (UTC)

The optic gland is mentioned in both the text and the references for the octopus article. Seasonality in living organisms is influenced in various ways by light sensitivity. See pineal gland for a homologous organ in vertebrates. μηδείς (talk) 23:09, 14 September 2012 (UTC)

That doesn't really answer all the various questions I posed. Quickly, anyone, before this topic gets archived off the Reference Desk? —SeekingAnswers (reply) 01:58, 18 September 2012 (UTC)

Google: cephalopod optic gland. μηδείς (talk) 02:29, 18 September 2012 (UTC)

How do they determine how many figures are "correct" or "good" for a given computation of a mathematical constant, like pi?

I'm doing a significant figures problem from a chemistry textbook that goes like: carry out the calculation, making sure your answer has the correct number of significant figures, $V=\pi r^{2}h$, where r = 6.23 cm and h = 4.630 cm. Please don't get hung up on that particular thing; I know how to do the problem. And I can safely assume that I know pi to more than two correct figures. But how to they really know, when they do a given computation of one of the many mathematical definitions of pi, "OK, this time the computation is correct to 10,478,352 figures. How do they get the number of correct figures, or figures that they say are correct? 20.137.18.53 (talk) 15:40, 14 September 2012 (UTC)

If your read the "Infinite series" section of our "Pi" article, you will see that pi is calculated with an infinite series. The terms that are being added or subtracted keep getting smaller and smaller as the series is computed. So you can estimate the uncertainty by the size of the last term that was added or subtracted. Jc3s5h (talk) 15:56, 14 September 2012 (UTC)

(after ec) Our article Pi covers this in reasonable detail, but I can give a short version here: the value of pi (or e, or phi, or any other constant) is calculated using infinite series. These are known to sum to the correct values - generally, the description of the series is related in some way to the definition of the constant. So to get the appropriate number of decimal places, you calculate and sum terms of the series until the sum stops changing at the level of accuracy you need. So if I want to show that (say) the sum of the reciprocals of powers of 2 is 2, correct to 2sf, I'd work out terms like this:

1/(2^0) = 1

1 + 1/(2^1) = 1.5

1 + 1/(2^1) + 1/(2^2) = 1.75

1 + 1/(2^1) + 1/(2^2) + 1/(2^3) = 1.875

1 + 1/(2^1) + 1/(2^2) + 1/(2^3) + 1/(2^4) = 1.9375

1 + 1/(2^1) + 1/(2^2) + 1/(2^3) + 1/(2^4) + 1/(2^5) = 1.96875

1 + 1/(2^1) + 1/(2^2) + 1/(2^3) + 1/(2^4) + 1/(2^5) + 1/(2^6) = 1.984375

And at that point, the last two terms are both 2.0, correct to 2sf. (Of course, there's more to it than that; be careful of examples like the Harmonic series.) For engineering purposes, only a few digits of pi is enough. You could probably take pi = 22/7 a lot of the time and get away with it. Mathematicians have known how to calculate pi to more places than could be needed for any real-world application for centuries. AlexTiefling (talk) 16:01, 14 September 2012 (UTC)

(another EC) See also Approximation_of_pi#Modern_algorithms and rate of convergence. Basically, fancy math can tell us that the (numbers made up for sake of example:) 100th term of a sequence is less than 0.000001 from pi. So that tells us that at least the first four decimal places are correct. SemanticMantis (talk) 16:03, 14 September 2012 (UTC)

Sorry, are we answering the OPs question properly? Or is the OP answering the textbook's question properly? Isn't the issue about how many significant digits to include in the answer to the problem? I thought the rule was that the answer should not be less significant, but need not be more significant than the least significant input variable. I.e., 564.56 cm**3, rather than 564.556 cm**3 (because r is only as precise as 6.23cm. The infinite precision of pi is redundant. Your Username 16:14, 14 September 2012 (UTC) — Preceding unsigned comment added by Hayttom (talk • contribs)

No, my question was about how it is determined how many figures of a computation of a mathematical constant such as pi are correct. I only brought up the significant figures problem as background to what made me think about how it is determined how many figures of a mathematical constant are determined to be correct when computing said mathematical constant. 20.137.18.53 (talk) 16:18, 14 September 2012 (UTC)

pi and e are transcendental; the digits go on forever, without repeating. So there's no perfectly correct way of writing out their decimal forms (without an infinite piece of paper). A textbook author might decide they only care about the first few digits, but that's just their definition. For physical things, like a temperature measurement, the equipment is only so accurate, so you might only quote a temperature with one digit after the point, because that's how accurate your thermometer is - if you had a super-accurate digital thermometer you could reasonably use more digits. -- Finlay McWalterჷTalk 17:12, 14 September 2012 (UTC)

My question was just how people determine that a given calculation is correct to n digits. I think I get the infinite series each-time-a-smaller-amount-is-added reasoning given above. 20.137.18.53 (talk) 17:32, 14 September 2012 (UTC)

It is also fairly easy to get a series of approximations which you can prove alternate between being above and below pi. Having a lower and upper bound makes the accuracy easy. When you are 14 or 15 at school you derive one like that based on the series expansion of arctan (1/5) or you used to when they still did maths at school. --BozMo talk 17:38, 14 September 2012 (UTC)

Interesting article: Bailey–Borwein–Plouffe formula. In which you can get a digit of pi without figuring out the whole thing! Weirdest part? "Certain combinations of specific p, q and b result in well-known constants, but there is no systematic algorithm for finding the appropriate combinations and known formulas are discovered through experimental mathematics." Now is that a red cape to the bull or what? Wnt (talk) 18:49, 14 September 2012 (UTC)

You basically have to methologically go through all the possible sources of error and determine their size. The sum of these possible errors together determine how many accurate figures you have. In the pi example, you have two sources of error: a) you are only summing a finite number of terms of an infinite sequence: so estimate what the total size of the missing terms is and b) round-off errors if you are doing this on a computer: roughly number-of-terms * machine precision (usually 1e-16). In your volume of cylinder example above that contains measurements: how did you obtain those measurements? How many digits do you trust. To get more than a mm accuracy you will need special equipment, so likely already the last digit of 6.23cm is bogus. This becomes especially apparent if you see statistical claims like "14.28% of people like X". By what method could they have possibly determined that to 4sf? The possible sources of errors in these statements are many and are very rarely all accounted for.86.139.178.200 (talk) 22:04, 14 September 2012 (UTC)

Taylor's_theorem#Estimates_for_the_remainder may also be of interest to the OP. --NorwegianBlue ^talk 11:49, 16 September 2012 (UTC)

Human viruses

Please can someone confirm that HPV is not the same as herpes? This is not a request for medical advice. It's to answer a pub discussion! --TammyMoet (talk) 18:33, 14 September 2012 (UTC)

See Human papillomavirus and Herpes simplex virus. Totally different families of viruses. Wnt (talk) 18:40, 14 September 2012 (UTC)

I suspect that the losing party was confusing HPV with HSV, due to similar abbreviations and similar means of transmission. StuRat (talk) 21:20, 14 September 2012 (UTC)

Yes thank you both. 1-0! --TammyMoet (talk) 09:43, 15 September 2012 (UTC)

You're welcome. I take it we can mark this resolved while you collect your bet ? StuRat (talk) 14:44, 15 September 2012 (UTC)

Resolved

does all the velocity increase come from the energy stored in air pressure when air is forced out of the lungs?

Or do the walls "accelerate" some of the air particles? I am thinking this is possible, because the average speed of air molecules (at 28 g/mol) at 300K is about 422 m/s (this accounts for 1 atm) -- so I find it conceivable that the lungs in forcing out air in a strong breath (1.5L/s) would also maybe provide kinetic energy equivalent to maybe 5% of the original PV = nRT -- maybe making the air move about 20m/s faster? That would be on the same order of magnitude as the pressure drop predicted by the Bernoulli equation, no? — Preceding unsigned comment added by 137.54.16.83 (talk) 19:55, 14 September 2012 (UTC)

Our thoracic diaphragm clearly moves as we exhale, not prior to exhaling, so it's not just releasing pent-up pressure. StuRat (talk) 21:08, 14 September 2012 (UTC)

Well I was thinking the Bernoulli equation would say conservation of energy means the pressure drops below atmospheric; but wouldn't the movement of the diaphragm contribute to the kinetic energy? 137.54.16.83 (talk) 22:48, 14 September 2012 (UTC)

Yes, so a bit of both. StuRat (talk) 20:43, 15 September 2012 (UTC)

The motion comes almost entirely from the diaphragm, and not at all from any change in the pressure of the air as such besuides that you impart to it by contraction. Simply open your mouth, relax your diaphragm, and don't breath. There will be no air flow. Your body is heating the air inside your lungs, so yes, a negligible amount will flow out. And there is an exchange of one carbon dioxide molecule for one oxygen molecule due to respiration. But that exchange will largely cancel out, and be negligible in increasing outflow as well. (If you breath out entirely and then hold your breath your lungs will partially refill and you can exhale a little bit more after a few seconds.) You can safely attribute all the airflow to the change in volume due to the contraction of the chest and diaphragm in normal circumstances. μηδείς (talk) 02:27, 18 September 2012 (UTC)

five woody clades

In The Island of the Colorblind, part of which is about cycads, Oliver Sacks mentions in passing that nature invented wood five times. I guess cycads, conifers and palms are three of these. Are broadleaf trees one clade or two? If one, what is the fifth woody clade? Bamboo? —Tamfang (talk) 20:02, 14 September 2012 (UTC)

The so-called wood of monocots (icluding palms and bamboo) is not true wood because, although hard and "woody", it does not grow laterally from secondary xylem but apically from primary growth. The article on xylem lists five clades with more or less true wood, cycads, ginkoes, gnetophytes, conifers, and angiosperms. Note that these five clades entirely comprise the living Spermatophyta, or higher seed plants. Whether wood arose separately in each is debatable and dubious. The most primitive angiosperms include Amborella and Nymphaeales, such as Nelumbo, neither of which is truly woody. But each may have lost a primitive woody state. All other most primitive angiosperms such as the Magnolia are woody. μηδείς (talk) 20:45, 14 September 2012 (UTC)

Let me comment that "clade" is the wrong word here. A clade consists of any species together with all of its evolutionary descendants, so clades can range from a single existing species to the entire animal kingdom. Broadleaf trees do not form a clade, but that doesn't have any bearing on this question. Regarding the question, I don't know the answer, but I'll add that tree ferns are another pseudo-woody group that are distinct from the ones that have been mentioned so far. Looie496 (talk) 21:43, 14 September 2012 (UTC)

The five groups I mentioned (and which I assume are the ones Sacks meant) are all considered valid clades. There is no objective definition of "broadleafed". μηδείς (talk) 23:02, 14 September 2012 (UTC)

Thank you. —Tamfang (talk) 00:24, 16 September 2012 (UTC)

Why is clade a wrong word? The question is about sets of species descended from a common woody ancestor whose own ancestors were not woody. —Tamfang (talk) 00:24, 16 September 2012 (UTC)

If you equate broadleaf and angiosperm, then since angiosperms are indeed a valid clade, broadleafed plants would, of course be a clade. I and Looie (I presume) were taking it to be a phenetic characteristic, like deciduous, and in my case was including Welwitschia and Ginko which have broad leaves, not needles or scales. I see someone has pointed broadleaf to angiosperm only now, so see why the question would arise. I think that piping is problematic. μηδείς (talk) 00:31, 16 September 2012 (UTC)

Purple carrots

My V8 V-Fusion drink contains purple carrot juice, yet I've never seen purple carrots sold directly in that store. Is there a reason why purple carrots aren't sold directly to consumers, or is my store just slow in changing ? StuRat (talk) 20:55, 14 September 2012 (UTC)

I buy them at the St Lawrence Market in Toronto, and have for several years. They also come in red and yellow (and the usual orange, of course). Bielle (talk)

Picture? Source? μηδείς (talk) 21:02, 14 September 2012 (UTC)

I don't need a source, I trust Bielle not to lie to me. StuRat (talk) 21:03, 14 September 2012 (UTC)

Thank you, StuRat. Nonetheless, according to this site, carrots were purple before they were orange. And there are black carrots, too. The site has photos. Bielle (talk) 21:06, 14 September 2012 (UTC)

It would seem from their names that oranges were orange before carrots were. Also, look at the (similar) spectrum of colors carotene can produce in tomatoes.Gzuckier (talk) 03:43, 17 September 2012 (UTC)

I think Medeis was challenging your statement that they are available at that particular store. This is a case where sources are unnecessary, since we have no reason to doubt your word. StuRat (talk) 21:10, 14 September 2012 (UTC)

This 2000 article say there's no consumer demand for them, but I wonder how they determined that: [3]. StuRat (talk) 21:03, 14 September 2012 (UTC)

See also Carrot for this photo among a number of others. A small restaurant in my only-slightly-larger small town serves several dishes with a bouquet of coloured carrots for "seasonal veg". I wonder if Murry (yes, that is how he spells it), the root-vegetable seller at the market might be prepared to bring a sample of his many-coloured carrots out to the street where the market sign identifies the location. I might have more success photographing a dish in the local restaurant; Costa and Annnika love any kind of publicity. But then I would have to learn how to upload photos. No, not going there; sorry, Medeis. Bielle (talk) 21:21, 14 September 2012 (UTC)

I wasn't challenging the veracity. I simply wanted to see and read about these carrots. I love carrots and love purple, so what's not to like? μηδείς (talk) 21:30, 14 September 2012 (UTC)

As a Ref Desk regular, Medeis, I am surprised you didn't immediately think of Carrot. :>) Bielle (talk) 21:48, 14 September 2012 (UTC)

As a ref desk regular I am surprised (actually, not surprised at all) that you didn't provide a link with your first response. μηδείς (talk) 22:55, 14 September 2012 (UTC)

Yes, I linked to our article in the title. If the carrot doesn't work to get Medeis to go to the article, perhaps we need to employ the stick ?  :-) StuRat (talk) 22:03, 14 September 2012 (UTC)

If not the carrot, then the trout, perhaps. I didn't see that link either. The dark blue doesn't show up well beside the black. Wasn't linking a lighter blue at one time? Ignore that: I worked it out. I just didn't look at the title, obviously.Bielle (talk) 22:13, 14 September 2012 (UTC)

Alack, our article on wild carrot - and associated Commons material - contain no roots. We need pictures like [4] and [5]. Our article actually claims the orange carrots are the result of the House of Orange, which would be a very odd twist of fate indeed. Wnt (talk) 22:36, 14 September 2012 (UTC)

It doesn't seem all that outrageous that orange carrots were bred to honor the House of Orange. This was the Dutch, remember. They caused an economic collapse over Tulips. They take their horticulture seriously. --Jayron32 03:37, 15 September 2012 (UTC)

In my neck of the woods, you can take your horticulture but you can't make her appreciate it. -- ♬ Jack of Oz ♬ ^{[your turn]} 23:07, 15 September 2012 (UTC)

* One of Medeis stars for you JackofOz. That's the answer of the week. --Jayron32 03:17, 16 September 2012 (UTC)

To earn the star, I think Jack should have given a tip of his hat at least to Dorothy Parker. Bielle (talk) 03:32, 16 September 2012 (UTC)

Oh, pooh on you, Bielle. What is this, some boring place where we're supposed to produce references for our statements?  :)  :) -- ♬ Jack of Oz ♬ ^{[your turn]} 03:40, 16 September 2012 (UTC)

Not really a reference (because the actual quote is "You can lead a horticulture, but you can't make her think." See previous comment for source) but just a "with thanks to dear Dot" or something like. :>) Bielle (talk) 22:11, 16 September 2012 (UTC)

Fair call. I didn't attribute it because I assumed it was as widely known in its country of origin - more so, in fact - than over here. I never expected anything like a star. Would you like to borrow it for a day or so?  :) -- ♬ Jack of Oz ♬ ^{[your turn]} 07:46, 17 September 2012 (UTC)

"Nutty" taste in cheese

What gives cheese a "nutty" flavor? Except for instances where nuts are actually inserted into cheese, I don't see where nuts would come into play in the cheesemaking process. Is this a result of the animal's diet? Also, can nutty cheeses provoke allergic reactions in people who are allergic to nuts—either a legitimate reaction or a sort of false positive based on the body's perception of nut consumption? I've looked over a few sources such as this study from North Carolina State University, but if the answer is in there, I think I'll need someone to translate it into layman's terms for me. --BDD (talk) 21:23, 14 September 2012 (UTC)

If you come up with the answer you could patent an artificial nuttiness process and make millions scrimping on aging time.

http://www.foodnavigator.com/Science-Nutrition/Scientists-unlock-nutty-flavours-in-cheddar-cheese

Hcobb (talk) 21:49, 14 September 2012 (UTC)

Thanks—that's definitely the sort of source I'm looking for. If I'm reading that right, we don't really know what gives cheeses a nutty flavor, although that study identified compounds that could do so? --BDD (talk) 21:59, 14 September 2012 (UTC)

They seem to be making the hypothesis that A+B(+C...?) is responsible for the nutty flavor, and they believe they have found A. This is evidenced by the fact that when added to young cheese, their compound does not significantly alter the flavor, but added to older cheeses, they see significant increases in nuttiness. Someguy1221 (talk) 23:08, 14 September 2012 (UTC)

Eggs, water, and temperature

I was steaming some eggs when the following question occurred to me: which of these two has a higher boiling point (edit:) reaches the higher temperature during steaming?

• cracked-open (liquid) chicken eggs alone
• cracked-open (liquid) chicken eggs diluted with water

—SeekingAnswers (reply) 21:24, 14 September 2012 (UTC)

I am a seasoned cook, but I am not sure I understand the question. Do you mean boiling eggs without water in the first place? They will denature then burn, but not really boil other than giving off steam. μηδείς (talk) 21:32, 14 September 2012 (UTC)

As the question states, I am steaming the eggs, so in the first case, the eggs are placed in a steamer above liquid water. In the second case, the eggs are diluted with water before being placed in the steamer above liquid water. —SeekingAnswers (reply) 22:04, 14 September 2012 (UTC)

Well, what's the boiling point of liquid egg? I couldn't find that with a quick search, but if we know that, we can deduce the answer to your question. If the boiling point of a liquid egg (x, for convenience) is higher than the boiling point of water, we can expect the dilution to have a lower boiling point; if x is lower than the boiling point of water, we can expect the dilution to have a higher boiling point. But you may have already figured out that much. --BDD (talk) 21:48, 14 September 2012 (UTC)

Egg liquid can never boil. It congeals (turns solid) at a temperature of about 150 degrees Farenheit. If you continue heating it, it gets steadily more rubbery, then turns brown, then black, then starts to smoke. Looie496 (talk) 22:01, 14 September 2012 (UTC)

Let me rephrase (and I've edited my original question accordingly). The question I really wanted to ask was which of the two cases I gave (without water dilution and with water dilution) reaches the higher temperature during the steaming process. (I only mentioned the boiling point because liquid water reaches its maximum temperature during cooking at the boiling point, after which it vaporizes into steam, so I assumed peak temperature for liquid eggs was also their boiling point.) —SeekingAnswers (reply) 22:08, 14 September 2012 (UTC)

It is not correct to think that once water turns to steam it is past its highest heat conductivity. Steam burns are actually worse than those from splashed boiling water. Steam conveys much more heat than boiling water. See steam and heat of evaporation. So long as the steam is not under pressure, it will not cook the egg to a much higher temperature than boiling water. But it does convey that heat much more quickly, which is why it is used as a cooking method. Adding some water to the mix will slow down the cooking, since the water will absorb some of the ambient heat. Added water will slow the cooking and help prevent overcooking, to a degree. μηδείς (talk) 22:50, 14 September 2012 (UTC)

(edit conflict) Boiling point of a mixture of components is not the average of the components' individual boiling points. See Distillation for the extremely common situation, where each behaves approximately independently, azeotrope, where "high bp + higher bp = lower-bp mix", and boiling-point elevation, where substances with extremely high bp only create a comparably small increase of bp. Back to the original question, BDD does lead in an interesting direction: does steaming really involve the egg itself boiling, or just being exposed to boiling water? And if "the egg" is boiling, is it maybe just the water of the egg boiling out of the [solid and other gooey parts]? Egg (food)#Cooking issues gives a coagulation temperature well below the boiling point of water. DMacks (talk) 22:11, 14 September 2012 (UTC)

So, can someone answer the revised question, please? Thanks. —SeekingAnswers (reply) 18:00, 16 September 2012 (UTC)

Without hard proof, my informed hunch would be that neither gets anywhere near their boiling point, so that the temperature each would reach assuming equal delivery of heat via steam would be a function of their heat capacity, which I am (again) guessing would be higher for water than for egg-stuff, therefore the diluted egg would not reach as high a temp for equal heat delivery. Gzuckier (talk) 03:48, 17 September 2012 (UTC)

So if T is a function representing maximum temperature of something while it is steamed, if I'm understanding you correctly, you're saying that T(eggs + water) < T(eggs) < T(water)? But if water having higher heat capacity than eggs causes T(eggs + water) to be less than T(eggs), then why is it the case that both are less then T(water)? —SeekingAnswers (reply) 15:07, 17 September 2012 (UTC)

Zopiclone

Can anyone find out how long a tablet of Zopiclone is good for? Best guesses, and even "usually", are not useful; I can make those estimates myself, thanks. The WP article doesn't say. I'd really like a solid source. Bielle (talk) 22:35, 14 September 2012 (UTC)

I hate to disappoint you, but the only place you're going to get an answer is the manufacturer for that pill, whatever brand it is, whenever it was made, and even that is a guess. (Manufacturers have little incentive to say just how long something will last; saying "good for a year" is often good enough for them. However, it had better last for at least as long as they say.) But a different preparation might have different pH, different excipients; the lifespan of a pill is based on the entire pill (and the bottle it comes in!), not just the active ingredient. Wnt (talk) 22:52, 14 September 2012 (UTC)

From a practical standpoint, the lifetime of a particular pill will depend on the conditions under which it is stored. (Light, heat, and high humidity tend to be detrimental; the cabinet in the bathroom right next to the shower – you know, where everyone keeps their pill bottles – is probably one of the worst places to store drugs. [6]) If you want to know if your older prescription medications are still good, then your best bet is to ask your pharmacist. Not only will they know the shelf life, but they may also be able to advise you on how to tell if a particular medication has gone off. It wouldn't be appropriate for Wikipedia editors to advise you further. TenOfAllTrades(talk) 23:13, 14 September 2012 (UTC)

I'm hesitant to contribute after TenOfAllTrades' final sentence, but am a bit confused about your question: doesn't the box have an expiry date? I happen to have a box of Zopiclone bought in Norway in July, 2012, that has an expiry date of January 2015. This is consistent with the proposal from the UK Medicines and Healthcare products Regulatory Agency, [7]: "A shelf life of 36 months at 25°C is proposed." --NorwegianBlue ^talk 00:39, 15 September 2012 (UTC)

Our drugs are frequently, but not always, decanted. It has something to do with the Canadian government being the controller of the purchase and sale prices. Thank you for the reference. That's useful information, not advice. Bielle (talk) 03:40, 15 September 2012 (UTC)

Fungus growing without an apparent food source

I often find fungus growing in my bottles of phosphate buffer, which have been autoclaved on top of not containing anything that should support microbial growth. Seriously, water, salts (sodium, potassium, chloride, magnesium, phosphate), glass bottle. What the hell is the fungus growing on? It's always the same thing, too - a boring filamentous white fungus (sorry, no pictures). Could it be eating some trace sugars/bacteria in the bottle? Is it fixing carbon dioxide out of the air? Curiously, it doesn't spontaneously appear in other buffers in the lab. Just the one I described. Someguy1221 (talk) 23:01, 14 September 2012 (UTC)

Something got contaminated somewhere. Fungi can't grow without a source of carbon and nitrogen, and they can't fix either from the atmosphere. Nor can they survive autoclaving. First step in this case is to replace your reagents. Try the ones from the lab next door. If the problem persists, try reagents from another producer, or of a higher grade if you're not using p.a. The water and glass seem not to be the problem as your other buffers would be probably be affected, but it would be worthwhile to check your distiller, washing and autoclaving procedures as well. Another possibility is the seal on the cap you use. Try using a groud glass stopped bottle. Dominus Vobisdu (talk) 23:15, 14 September 2012 (UTC)

And are you certain it's a fungus ? I can imagine salts forming threadlike crystals under the proper circumstances. StuRat (talk) 23:27, 14 September 2012 (UTC)

If put the threads on an agar dish they grow, so, yeah. Someguy1221 (talk) 23:29, 14 September 2012 (UTC)

Fungal hyphae are rather distinct from plants and bacteria. Next time take pictures and post them. μηδείς (talk) 00:23, 15 September 2012 (UTC)

Indeed. A similar question nagging me all my (clearly boring) life; what exactly is the nutritional source for the mildew that eventually shows up on cleaned bathroom tile and other substances which are moist but essentially contain no organic foodstuffs? Gzuckier (talk) 03:52, 17 September 2012 (UTC)

I'd guess the tile isn't as clean as you think. Even a few specks of dust may contain enough nutrients for it. That and whatever is deposited by water drops and pulled directly out of the air. StuRat (talk) 03:13, 18 September 2012 (UTC)

Privacy among other animals

This is sort of a sequel to my previous question about social taboos in other animals. Humans are known for this concept called "privacy", but are we the only animals with it? I'm sure at least other mammals would be familiar with the concept of "privacy", especially when it comes to raising their young, but I can't seem to find anything about it online. Are there any other animals other than humans who have the concept of "privacy" and take it very seriously? I asked this because it seems no other animal is squeamish when it comes to being naked or mating. Narutolovehinata5 ^tccsdnew 23:25, 14 September 2012 (UTC)

Some cats seem to want privacy when they defecate. This might have developed since they are vulnerable then, therefore it's best to be alone, so nothing can attack them. StuRat (talk) 23:29, 14 September 2012 (UTC)

Many animals also like privacy when they eat, presumably so nobody can steal their meal. StuRat (talk) 23:30, 14 September 2012 (UTC)

Once again you are looking at the issue of conceptualization. Human children will happily defecate and play with themselves in public, until they are taught the idea of privacy. Animals may become aggressive or shy (which is chemically mediated) when eating, defecating, or copulating, while all evidence points to humans needing to learn this. My five year old nephew is only just mastering this, since he will insist on privacy rather hilariously when he goes to the bathroom (he doesn't even want you to realize why he is in the bathroom) then take out his penis and show you his foreskin without any shame whatsoever. Jean Piaget normally covers the development of such concepts, but I haven't found anything relevant. The notion of privacy itself is very culture-relative. Apparently, the Russian language (according to privacy) has no such word, the closest being "secrecy". I would suggest that you consider that notions that need to be taught to children using words are unlikely to exist among animals except metaphorically. μηδείς (talk) 23:52, 14 September 2012 (UTC)

The absence of a single word for a concept in a certain language doesn't mean that the notion doesn't exist in that culture. Russians are no different from anyone else in desiring privacy when they excrete or shower or copulate or masturbate, for example. English has to resort to wordy collocations to refer to concepts for which some other languages have a single word. But you're right, privacy and secrecy are intimately entwined, and for the longest time I had the greatest difficulty in keeping them separate in my private life. (I also had a strong affinity with all things Russian from an early age, with absolutely zero family heritage to account for it. Weird, that. I suspect I was Jack the Terrible in a previous life. Now, I'm just Jack the Terribly Impressive.) -- ♬ Jack of Oz ♬ ^{[your turn]} 23:03, 15 September 2012 (UTC)

If you find that you have a pet parrot with an intense urge to squeeze itself into dark corners of your home (e.g. beneath furniture, cupboards, drawers) and lurk there for hours at a time - just you try dislodging him/her without getting bitten or bickered loudly at. An urge for privacy? Perhaps... --Kurt Shaped Box (talk) 23:45, 14 September 2012 (UTC)

Privacy is not normally defined as an urge to be in the dark, but to be alone. Have you found a little stash of birdie porn mags and sex toys? μηδείς (talk) 00:20, 15 September 2012 (UTC)

An urge to be alone - but in the dark? With toys? (seriously - they do take their favourite objects in there with them sometimes). --Kurt Shaped Box (talk) 00:36, 15 September 2012 (UTC)

It's more the urge to be unobserved, I think, rather than to be alone. A microphone, camera or telescope can violate someone's privacy even while he is alone, while a person behind a thick wall does not. - Lindert (talk) 00:35, 15 September 2012 (UTC)

Cannabinol in NJ?

How could one find sources determining what the protocols are for prescribing marinol pills for a (chemotherapy patient) in New Jersey? Does its use even vary by state in the US? I am not interested in "medical marijuana", which was recently legalized, but the old-fashioned cannabinol pills supposedly meant to minimize abuse. Thanks. μηδείς (talk) 23:40, 14 September 2012 (UTC)

Note that Marinol is delta-9-tetrahydrocannabinol, the purified psychoactive component of marijuana. In healthy wild-type cannabis plants (i.e. "ditchweed") this is mostly converted to the closely related (and even more illegal) cannabidiol, a far less inebriating substance which has been credited with a variety of beneficial effects which, among other things, tend to offset some of the less desirable activities of THC. As I recall, some of the patients taking Marinol complained that it got them very high but wasn't as effective for their condition. So defining the idea of "minimize abuse" in this context is difficult. Wnt (talk) 00:31, 15 September 2012 (UTC)

Our article says that Marinol is Schedule III in the United States, so apparently any physician can prescribe it, and patients can even obtain refills on prescriptions. Wnt (talk) 00:33, 15 September 2012 (UTC)

Note: someone deleted part of this, without discussion. I stand by what I said. See Marinol#Comparisons_to_medical_marijuana. However, I should acknowledge that I was out of date - apparently a drug Sativex has been developed which incorporates both THC and CBD and is seeking FDA approval by 2013. [8]^[Archived] Of course, there is already a product on the market which incorporates both these compounds. Wnt (talk) 13:11, 18 September 2012 (UTC)

We should ask governor Chris Christie. It's apparent that he's had the munchies on more than one occasion. :-) StuRat (talk) 14:37, 15 September 2012 (UTC)

I think I may have misled with the focus of my question. I am not really concerned so much with medical marijuana or marinol itself as I am with the jurisdiction of regulation in prescribing controlled drugs. The notion arose because I know people in NY who have rather routine access to marinol, and am curious if it is regulated the same in other states. I know that how prescriptions for controlled substances are filled differs slightly in paperwork between NY and NJ (although this may be a perception of mine based on a change in federal law during between times when I had controlled prescriptions filled in both states). So, ignoring medical marijuana, since it is still illegal at the federal level, should one expect the way doctors are regulated in prescribing marinol is the same in all states, or would it vary? Thanks. μηδείς (talk) 18:13, 15 September 2012 (UTC)

The legal issue isn't something I'm very familiar with, but Marinol says it is Schedule III, which is less restrictive than the Schedule I or II to which many drugs have been assigned. Wnt (talk) 13:14, 18 September 2012 (UTC)

Added after this thread was archived: After a discussion with my pharmacist, I learned only certain doctors and certain pharmacies are licensed at the state level to prescribe and dispense marinol--not all pharmacies can fill a prescription for it. μηδείς (talk) 01:51, 21 September 2012 (UTC)