Wikipedia:Reference desk/Archives/Science/2012 December 2

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December 2

Garlic supplements

I take garlic supplements and usually buy whatever's on sale at the grocery store. I happened to notice that brand I bought last time, Sundown Naturals has 75 mgs of garlic. The brand I just bought today, Nature's Bounty has 1000 mgs of garlic. I realize that there's no established RDA for garlic, but I was surprised that the amounts are so wildly different. The lower dosage pill is bigger, too. I'm guessing that one of these companies is playing 'accounting games' with the amount of garlic and that one pill isn't really 13 times more potent than the other, but I don't know that. Can anyone shed some light on what's going on here? Thanks. — Preceding unsigned comment added by A Quest For Knowledge (talk • contribs) 01:26, 2 December 2012

The label for the Sundown product says it contains 400 mg of garlic extract, equivalent to 2000 mg of fresh garlic bulb. Looie496 (talk) 01:39, 2 December 2012 (UTC)

(edit conflict) Herbal supplement#Government regulations should provide some light; basically the entire world of herbal supplements is an impenetrable dark morass of unproven, untested, and unregulated products foisted on the public as "health". It's not harmful (maybe), so there's no reason you shouldn't be taking them, but otherwise, don't actually expect any real consistency or meaningful efficacy from over-the-counter herbal supplements, most of which are about as useful as snake oil. --Jayron32 01:41, 2 December 2012 (UTC)

@Looie496: Oh, that's interesting. The label has apparently changed since I bought it. A Quest For Knowledge (talk) 01:51, 2 December 2012 (UTC)

@Jayron32: I did a bit of research on garlic a couple months ago, and I don't think this was the article I read, but there appears to be some support for garlic and hypertension, Garlic 'remedy for hypertension'. A Quest For Knowledge (talk) 01:51, 2 December 2012 (UTC)

I am in no way doubting that there could be medically useful compounds in garlic. There very well may be. The issue is that the herbal supplement industry is essentially an unregulated industry with no set standards the way that actual medicines have. So yeah, the fact that there are compounds within garlic that reduce hypertension is to me unimportant to the discussion at hand. The question is whether pills in stores by random manufacturers which report some content of "garlic" are useful or consistent. They are different questions. --Jayron32 01:55, 2 December 2012 (UTC)

Plus, with all these vampire shows, like Twilight: Breaking Wind, I assume there's a plague of vampires right now, so having some garlic in your system to ward them off is a good idea. :-) StuRat (talk) 07:17, 2 December 2012 (UTC)

From a culinary point of view, eating garlic is much better than eating garlic pills. 2000mg is two grams, or about one clove - a homeopathic dosis, as far as my cooking is concerned. The natural unit of measurement is the bulb, not the clove ;-). --Stephan Schulz (talk) 08:52, 2 December 2012 (UTC)

There are some of us who hate garlic. And, even for those who love it, do you really want to smell like garlic ? StuRat (talk) 09:12, 2 December 2012 (UTC)

Well, the unenlightened need to become enlightened. And I'm not sure that "smell" is the proper term to use for the heavenly fragrance that garlic and its disciples contribute to the universe. More seriously, I've cooked some meals for people who claim to not like garlic, and they where quite happy with it. It always depends not only on "how much", but also on "how", with garlic added early and sautéed a bit being much easier on the stomach and more discrete on the taste buds than raw garlic. --Stephan Schulz (talk) 09:20, 2 December 2012 (UTC)

Those who love it have no problem with it, by definition. Garlic on the breath of someone who's eaten it in the past few hours is not unpleasant. In fact, it might be a damn sight better than it would otherwise be. It's only a problem on people who haven't showered for a day or more, and the weather is warm. Then, it comes out in their pores and mingles with their sweat and becomes pretty yucky. But a garlic eater who attends to their daily personal hygiene doesn't normally find their smell is a problem for others. -- Jack of Oz ^[Talk] 10:23, 3 December 2012 (UTC)

• Sorry I didn't notice this before. The author is Karin Ried, who has published some articles [1] most recently [2]. "Mean systolic blood pressure was significantly reduced by 11.8±5.4 mm Hg in the garlic-2-capsule group over 12 weeks compared with placebo (P=0.006), and reached borderline significant reduction in the garlic-4-capsule group at 8 weeks (−7.4±4.1 mm Hg, P=0.07)." With an n of 79 split into four groups... hmmmmmm... and the results are not dose dependent ... hmmmm. Not what I'd call a compelling result, but nonetheless, an interesting lead. Other reviews have commented on similar but similarly underpowered research before [3]. Note the best-scoring two capsule group took 480 mg of aged garlic extract and 1.2 mg S-allylcysteine. Wnt (talk) 03:50, 7 December 2012 (UTC)

I want to know some intersest things about how metal found

Any kind of metal — Preceding unsigned comment added by Summeru (talk • contribs) 11:04, 2 December 2012 (UTC)

Iron can fall from the sky in the form of an iron meteorite. It can then be found lying on the ground. You may also be interested in the metal detector. Graeme Bartlett (talk) 12:04, 2 December 2012 (UTC)

In the spirit of providing interesting things about how metal is found, you might enjoy reading some excerpts from Roughing It, a narrative account by Mark Twain about his experiences as a silver miner in Nevada (and other excitement in the old West). Perhaps the author embellishes a little bit, but as far as I can tell, he presents an incredibly interesting (and quite potentially factual) account of ore extraction and processing. Chapter XXIX, Out Prospecting; Chapter XXXVI, A Quartz Mill and Ore Processing; Chapter LX, Pocket Mining, Placer Mining, and Mining Technicalities; and essentially everywhere else in the book, scattered bits of wisdom about silver and gold mining in the mid-nineteenth century. For an encyclopedic overview, we have articles on silver mining. Nimur (talk) 14:02, 2 December 2012 (UTC)

Maybe this is about discovery. (From our article on nickel): "In medieval Germany, a red mineral was found in the Erzgebirge (Ore Mountains) that resembled copper ore. However, when miners were unable to extract any copper from it, they blamed a mischievous sprite of German mythology, Nickel (similar to Old Nick), for besetting the copper. They called this ore Kupfernickel from the German Kupfer for copper. ... In 1751, Baron Axel Fredrik Cronstedt was trying to extract copper from kupfernickel—and instead produced a white metal that he named after the spirit that had given its name to the mineral, nickel."--Fuhghettaboutit (talk) 14:43, 2 December 2012 (UTC)

metal from Lithium and magnesium to cooper and silver and gold had been exist in earth crust and found by man for duration of some thousand years,we dont know clearly about first mining and how could man find minerals,but the usage of minerals and metal goes to age 8-9 thousand years ago. now we have instruments and high technology for mining ,the way of separating of mineral matters on earth crust refers to its molten core and diffraction of layers for duration of its life(4.6 billion years)--Akbarmohammadzade (talk) 15:03, 2 December 2012 (UTC)-

Akbarmohammadzade, I know you are trying to help, but if you want to answer a question in English, please follow some basic rules of the English language and of this page. It is really hard to read otherwise, and therefore not so useful to the original poster of the question.

1. The first word of a sentence should a capital letter. ("Now we have... ", not "now we have...".)

2. Proper nouns should also be capitalise (Earth crust, not earth crust).

3. Don't use automatically translated language, it is so wrong that we can't make sense of it.

4. Questions should end with a question mark.

5. Here we provide references (this is the reference desk), so the idea is that we point the user to specific pages within or outside wikipedia. So if you could link your answer to the relevant wikipedia page (for example did you mean molten core ?). --Lgriot (talk) 14:32, 3 December 2012 (UTC)

As a general rule, if you're going to criticise someone else's writing, you should ensure yours is flawless first. "Proper nouns should also be capitalise" is bad grammar, your last sentence is an incomplete fragment, question marks are not preceded by spaces, and Wikipedia is a proper noun and should begin with a capital letter. Akbar's comment wasn't particularly hard to decipher, in my opinion. – NULL ‹talk›
‹edits› 23:02, 5 December 2012 (UTC)

Fair enough, I was trying to give him/her advice, but if you guys feel I'm only criticising, I'll just keep quiet and won't try to help anyone anymore. --Lgriot (talk) 14:33, 6 December 2012 (UTC)

Muprhys law biatch! 203.112.82.1 (talk) 17:26, 5 February 2013 (UTC)

Photobiolysis

Do we have an article? Is there a missing redirect? Did I make a typo? See [here] for an explanation of what the term means. As of 13:32, 2 December 2012 (UTC), the title of the question is a redlink. Thanks, NorwegianBlue ^talk 13:32, 2 December 2012 (UTC)

Biohydrogen, Photohydrogen, and Biohydrogen reactor all seem to be related. To which, if any, "Photobiolysis" should redirect I'll leave to others more versed in the material. Deor (talk) 17:08, 2 December 2012 (UTC)

Thanks. I came across the word when trying to assist my daughter with homework; it appeared in a chapter about using hydrogen as fuel. It now occurred to me to try search for Biophotolysis instead of Photobiolysis. The term Photolysis is well established, and biophotolysis is a special case, driven by biological processes, so the latter term makes more sense than the former. And indeed, on google scholar, biophotolysis seemed to be the preferred term, and also occurs in our article Hydrogen production, so maybe that would be the best place to redirect biophotolysis. A bit confusing though, if a user gets redirected there, and searches for photobiolysis to locate what he's looking for. NorwegianBlue ^talk 20:56, 2 December 2012 (UTC)

what does burn in nature

we had discussion about matters does burn by fire . they said :only matters made of carbon does burning.what about others? --Akbarmohammadzade (talk) 14:41, 2 December 2012 (UTC)— Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 14:40, 2 December 2012 (UTC)

Many elements burn, including metals and hydrogen gas. Most pyrotechnics do not seem to have carbon. DMacks (talk) 17:02, 2 December 2012 (UTC)

If you can oxidate it, you can burn it. When you "burn" something you simply combine it with oxygen, you oxidize it. Magnesium burns, and it's not organic, for example. OsmanRF34 (talk) 20:11, 2 December 2012 (UTC)

And the oxidizer doesn't even have to be oxygen -- it can be hydrogen peroxide, any of the halogens, any nitrate or perchlorate compounds, etc., etc. In fact, alkali metals spontaneously combust in water, while the aforementioned magnesium burns very well in carbon dioxide... 24.23.196.85 (talk) 00:38, 3 December 2012 (UTC)

Could somebody explain what is meant by "the oxidiser can be a halogen" please? thankyou.124.191.177.160 (talk) 07:23, 3 December 2012 (UTC)

Oxygen's role in burning is to capture electrons from other atoms, to raise their oxidation state (see redox). But oxygen is not the only molecule that can fill this role. Many materials will also burn in a halogen atmosphere, such as chlorine, even when no oxygen is present. Someguy1221 (talk) 07:29, 3 December 2012 (UTC)

And of course I think most people would consider the sun to be "burning", but there's no oxygen anywhere near it, but that's a very different kind of burning then what we would see naturally on earth. Vespine (talk) 21:38, 2 December 2012 (UTC)

Say what? Our Sun article says that it is about 0.77% oxygen by mass. 192.220.135.34 (talk) 00:59, 5 December 2012 (UTC)

Based on our articles on the Earth and the Sun, there's about 8500 times as much oxygen in the sun that in the earth (atmosphere plus crust, etc). Funny. Of course, most of the oxygen (on Earth and Sun) is not molecular oxygen. -- Scray (talk) 01:43, 5 December 2012 (UTC)

Ok, sorry, you are right, there IS oxygen near it, but the vast majority of the "burning" on the sun does not involve the oxygen, it involves hydrogen converting into helium. If there was NO oxygen there, the process would remain the same. Vespine (talk) 22:18, 5 December 2012 (UTC)

Chemical combination with oxygen is known oxidation but burning is fast combination with flam and warming .faster one is exploding. the iron does oxidation but slowly ,Lithium oxidation cause its fast rotating and magnesium burns with bright flame. sulfur and phosphor are burn too. Can we define burning such as this : Chemical combination with flame and high temperature?--78.38.28.3 (talk) 07:57, 4 December 2012 (UTC)(when any meteorite inters to atmosphere it burns , but for high friction)

what do you thinking about this questions?

پرسش از چگونگی اندر کنش گرانش و فضا؟

گراویتون ها(ریزگانهای نامزد ترابری نیروی گرانش ،موجب خمیدگی فضا نمی شوند . حضور میدان در فضا با مبادله ذره تفاوت ماهوی دارد و این را اینشتین به خوبی درک کرده بود. ببینید شما روی صندلی نشسته اید و صندلی برروی سقف قرار دارد و سقف روی ستونها و ستونها روی قشری از پوسته زمین . مثال ساده فوق را اینطور تصور کنید : ذرات گراویتون از زمین (معلوم نیست از کجای زمین)به شما واجسام یادشده گسیل میشود . 1- چه عاملی باعث می شود زمین تشخیص دهد شما اینجائید تا ذره گسیل دارد؟ 2-چرا مواد و اشیا زیر شما بین شما و زمین سایه نمی اندازد؟(مانع برای رسیدن گراویتون) 3- چه چیزی به زمین می گوید شما چقدر جرم دارید تا همان اندازه گراویتون گسیل نماید. 4-گراویتون به هیچ و جه توجیهی برای افزایش شتاب به نسبت عکس مجذور ثانیه و شتاب یافتن ذره در میدان نمی آورد. 5-هیچ مبادله کوانتومی ذره استثنا از قانون پلانک و اصل طرد پائولی نیست. 6-ترازهای انرژی میدان جاذبه از اصل عدم قطعیت هایزنبرگ تبعیت نمی کند. 7-مبادله ذره قوانین کپلر و میدان جاذبه و حرکت در میدان جاذبه را نمی تواند توصیف کند. — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 14:43, 2 December 2012 (UTC)

This is the English Wikipedia and so this question written in Persian is not well suited here. Moreover, from what I can make out from machine translation, this appears to be a homework question, which we will not answer for you because it robs you of the ability to learn yourself. I will post machine translation of this answer into Persian. I hope it's less garbled than the translation I was given of your text.ویکیپدیای انگلیسی است و بنابراین این سوال است از این بخش است که به زبان فارسی نوشته شده است و مناسب اینجا نیست.علاوه بر این، از آنچه که من می توانم از ترجمه ماشینی، این به نظر می رسد یک سوال برای مشق شب، که ما آن را نمی خواهد جواب را برای شما به دلیل آن را به شما محروم می سازد از توانایی خود را یاد بگیرند. من به ترجمه ماشینی از این پاسخ را به زبان فارسی ارسال کنید. من امیدوارم که آن را در کمتر از ترجمه من از متن خود را به او داده شد درهم است.--Fuhghettaboutit (talk) 14:52, 2 December 2012 (UTC)

Gravitons (gravity transport candidate, not the curvature of space. Field presence in space has an inherent difference between the particle and the Einstein exchanged well understood. If you see sitting on the chair and sits on the roof and on the roof of the cortical columns and pillars of the earth's crust. Imagine a super simple way: Graviton particles from the ground (not sure which part of the land) will be sent to you Ballistics above. 1 - You are here to determine what causes the particles are emitted? 2 - Why the materials and objects between you and the ground you would not have a shadow? (Barrier for gravitons) 3 - What is the land mass tells you how you can send the same size gravitons. 4- Graviton anything quite excuse for the acceleration inversely square s and acceleration of particles by the field 5 - No swap Pauli exclusion principle is a quantum particle exception of Planck's law. 6 - Energy balances the gravitational field does not obey the Heisenberg uncertainty principle. 7 - sharing particles of the gravitational field and Kepler's laws of motion in the gravitational field can not describe. is this translation clear enough ? — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 15:12, 2 December 2012 (UTC)

your name is as difficult as my name,i cannot spell it. — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 15:18, 2 December 2012 (UTC) If you want to justify graviton field must first be applied to the total impedance playing field with those particles like photons in space to justify. Each crime should be displaced between Dvtraz energy part of the gravitational energy is emitted. According to Maxwell's equations for the gravitational field Nakarast and radiation or certain wavelengths of emitted gravitational field graviton is not so controversial as the transferor remains Abtr field. The concept of gravity as the curvature of space electrodynamic equations of motion of a particle with space-time with virtual Chharbdy tensor is solved. The extent of the equations Bapkhsh just purely particle radius dependent impedance or density or mass or unresolved issue is resolved--Akbarmohammadzade (talk) 15:46, 2 December 2012 (UTC)

I don't understand what you are trying to say, but you don't seem to have asked a question. You have just made a series of statements. --Tango (talk) 02:06, 3 December 2012 (UTC)

difference between theory and law

we have Faraday or Kepler or thermodynamic laws . so we have several theories about differences between theory and low: A common misconception is that scientific theories are rudimentary ideas that will eventually graduate into scientific laws when enough data and evidence has been accumulated. A theory does not change into a scientific law with the accumulation of new or better evidence. A theory will always remain a theory; a law will always remain a law.

http://en.wikipedia.org/wiki/Scientific_theory

A law differs from a scientific theory in that it does not posit a mechanism or explanation of phenomena: it is merely a distillation of the results of repeated observation. As such, a law is limited in applicability to circumstances resembling those already observed, and is often found to be false when extrapolated.

http://en.wikipedia.org/wiki/Scientific_law--Akbarmohammadzade (talk) 14:49, 2 December 2012 (UTC)

What's your question? --Mr.98 (talk) 15:32, 2 December 2012 (UTC)

something about how we say newton formulas law? — Preceding unsigned comment added by Akbarmohammadzade (talk • contribs) 15:43, 2 December 2012 (UTC)

I don't understand your question. You might like to read Newton's laws of motion and Physical law.--Shantavira|^{feed me} 18:03, 2 December 2012 (UTC)

His question is: Why do we say that Newton's Laws are laws, rather than theories? Good question. My stab at it would be this: We observe through a very large number of observations that they are true. Therefore we take them as basic principles (laws) which can form the starting point of theories. For example, Newton's laws of motion says Newton showed that these laws of motion, combined with his law of universal gravitation, explained Kepler's laws of planetary motion. So one thing explaining another thing is a theory, while the one thing itself is an assumption (and the assumption is a law if there's a lot of solid evidence for it). My question: If a law is subsequently shown to be not perfectly true, do we say that it remains a law? For example, are Newton's laws considered to be untrue under relativistic conditions? Duoduoduo (talk) 17:15, 3 December 2012 (UTC)

Thanks,the relativistic condition solved newton's laws shortages but all scientific references tell law to newton formulas for their role in classic mechanics.--78.38.28.3 (talk) 05:51, 4 December 2012 (UTC)

Roughly, a law is a simple statement of an important property. A theory is the deductive closure of a number of statements (each of which can be considered a law if you set the barrier of importance low enough). So indeed Newtons laws are the basis of classical mechanics. --Stephan Schulz (talk) 07:36, 4 December 2012 (UTC)

Looking for research on Tetrahydrocannabinoids (THC) use as appetite simulant in cats diagnosed with CHF vs: azotemia (cardiac vs: kidney) problems - common in some cats.

Tried the orexigenic route via Wiki without much success. We are currently using Mirtazapine per vet with mixed results.This guy is a lovable little furry person! — Preceding unsigned comment added by 99.146.148.92 (talk) 15:53, 2 December 2012 (UTC)

I think we probably ought to avoid giving advice here, even if it is for a cat rather than a human. Plus this is such a technical question that nobody except a vet could give useful advice anyway. Looie496 (talk) 16:27, 2 December 2012 (UTC)

Humans, being primates, have large livers meant to metabolize chemicals in plants. Carnivores do not. The popular press has a lot on the toxicity of marijuana to pets. I'd speak to your veterinarian, if I were you. μηδείς (talk) 16:45, 2 December 2012 (UTC)

Cats in particular are reputed to have livers which are not as good as detoxing things; phenols (pinesol, etc.) being a commonly cited example. Gzuckier (talk) 04:06, 3 December 2012 (UTC)

We are proscribed from providing medical advice (human and otherwise) here. This needs to be closed.Dncsky (talk) 17:42, 2 December 2012 (UTC)

Although it's obvious he wants to treat his cat, he has asked for research, which we can provide. μηδείς (talk) 17:56, 2 December 2012 (UTC)

Have you just tried more tempting foods ? I know my cat could never resist the oil from a can of tuna. (You can get the tuna packed in water, too, but that won't have as many calories for your cat.) Also, have you had the cat's mouth and throat checked ? A sore tooth or throat might make it avoid solid foods. StuRat (talk) 18:42, 2 December 2012 (UTC)

That kind of advice is against policy. I should add that Wikipedia assumes zero liability if tempting a cat with azotemia with nitrogen-rich fish causes a worsening of the condition, and anyone who actually has said cat indeed had best ask the vet some questions. However, a request for research is fully appropriate - we should endeavor to assist a scientist or future scientist looking for ideas. Wnt (talk) 02:12, 5 December 2012 (UTC)

Feline stomatitis is a common condition that causes cats not to eat. Both our cats went through it, and eventually recovered after the removal of most of their teeth. --`Trovatore (talk) 02:30, 5 December 2012 (UTC)

To begin with, let's link azotemia. I assume CHF is congestive heart failure? Cannabinoids have been studied in cats a few times, but looking for that and "appetite" gets me one 1972 review article. From a quick skim, it appears that CB1 agonists (substances akin to marijuana) have a favorable effect against development of congestive heart failure in rats. (I was in a hurry, so you should check [4] and make sure that's not a lie) Wnt (talk) 02:23, 5 December 2012 (UTC)

Synchronous belt as serpentine belts

I noticed that for most engines the serpentine belt is a multi-V belt. Is there any engine out there that uses synchronous belts as their serpentine belt? I can't see any reason they are not used other than the higher cost. But if cost is the only concern then some of the luxury and racing companies must've done it already. Google hasn't been helpful due to the synchronous belt/timing belt conflation.

Just to make it clear I'm not asking about timing belts; I'm asking about the belt that's used to transfer power from the crankshaft or camshaft to the various accessories. I'm wondering whether synchronous belts (commonly called "timing belts") have been used for this purpose.Dncsky (talk) 16:21, 2 December 2012 (UTC)

I'm sure some accessories have been driven off the camshaft drive. As an extreme example, Lotus built an Esprit for Mike Kimberley that had its PAS pump driven off the camshaft. I'd also take a punt that somebody has used an ancillary as a timing belt tensioner. Greglocock (talk) 22:18, 2 December 2012 (UTC)

Thanks, I'll look into that Esprit.Dncsky (talk) 22:28, 2 December 2012 (UTC)

Toothed belts offer lower friction power loss than V-belts - so toothed belts tend to be used where the power to be transmitted is higher. Ratbone 124.182.8.228 (talk) 00:06, 3 December 2012 (UTC)

Precisely. So I'm left wondering why doesn't all the high-end automakers use toothed belts instead of the basic V-belts. A thinner toothed belts can do the job of a wider V-belt, so it can help to shave a few grams off.Dncsky (talk) 02:04, 3 December 2012 (UTC)

Not only could you save weight, you could use a sync belt longer and transfer more power. If the belt is uniformly V-shaped (or multi-V for that matter), it seems to be compressed more on its way from the crankshaft and expanded by a greater amount on its way to the crankshaft than a similar sync belt. This does not only imply more physical stress due to the greater amount of expansion, but also due to abrasion if it slips and thermal stress because part of the deformation is converted into heat, which will age the belt.

And now to the really, really bad OR part (I still think it's correct...) All of the above is over-simplified, in that it assumes that a sync belt has uniform stress at "teeth" and "gaps". It's not the pull that counts, but the pull over cross-section, and this is not uniform in a sync belt. The gaps are the weak spots of the sync belt, and more precisely, the transition from teeth to gaps.

ASCII art of a sync belt (the numbers are for reference purposes only)

   ____      ____      ____      ____      ____   
__/    \____/    \____/    \____/    \____/    \__
01234567890123456789012345678901234567890123456789
--------------------------------------------------

The "12" and "78" parts of the belt are more fragile than the rest. If there is only a slight imperfection, it will grow under stress and snap.

On top of that, the teeth per revolution of either shaft must be an integer. Sync belts could still be of use for very large engines, where thermal losses could be an issue, but I think you could go the full nine yards there and use a chain, which is even more efficient.

This is OR too, but I'd guess that the efficiency of a chain would outweigh its weight penalty in these cases. - ¡Ouch! (^{hurt me} / _{more pain}) 07:19, 3 December 2012 (UTC)

Chains are not used for things such as driving the fan, as they would cost a lot more. A chain requires lubrication, which means it need to be enclosed. V-belts give an acceptable life without any lubrication. Ratbone 121.215.26.126 (talk) 08:41, 3 December 2012 (UTC)

Thanks for your input. I'm a little lost on your "must be an integer" point though. It was my impression that vehicle accessories did not need precise timing or speed; they must be able to function over a wide range of RPMs. Dncsky (talk) 14:52, 3 December 2012 (UTC)

You cannot design cogs with, say, 23 degrees spacing. Either 24 (that is, 15 teeth per revolution) or 22.5 (16 per revolution), but nothing in-between. Thus, sync belts would introduce some constraints on the transmission ratios, and there would have to be many different belts for different shafts.

Ratbone: you're right, and these issues are less (in a percentage POV) with huge and/or expensive engines. If the engine is 10 times the weight, the added complexity (e.g. for lubrication) is not 10 times the cost. For small-scale components like the fan (which receives only a tiny percentage of the total mechanical power), it pays off to use a light-weight belt which doesn't rely on lubrication. For the primary power transfer (not "accessories"), the added efficiency of a chain, with the added benefit of lower heat buildup) could be significant. - ¡Ouch! (^{hurt me} / _{more pain}) 15:58, 3 December 2012 (UTC)

Using your example, if 23 degrees is the ideal number, but we're forced to work with 22.5 due to the teeth constrain, then the accessory will be driven 2.2% slower (0.5/22.5). But since the crankshaft goes anywhere from 500 to 5000 rpm, all the accessories must be able to handle a 10x input range as well. In that respect 2.2% is negligible. Dncsky (talk) 03:39, 4 December 2012 (UTC)

Out of curiosity, might it be possible that a little bit of 'slip' in the serpentine belt is seen as a feature, and not a bug? When you turn the air conditioner on and off, for example, you're connecting a pretty substantial load. If the a/c clutch is a bit clunky then you'd be applying a nasty jerk to the rest of the peripherals – and directly to the crankshaft – if there wasn't room for just a little bit of slip on the pulleys. Worse, what if a bearing seizes suddenly on the power steering pump? With a sync belt or chain, that sudden stop is fed back instantly to everything that's connected, with potentially expensive consequences. Could the small efficiency penalty (2-5%) operating the parasitic loads be seen as a reasonable price to save wear and tear, and to protect all the rest of the components from a catastrophic failure of one? TenOfAllTrades(talk) 15:54, 3 December 2012 (UTC)

Fungus ID

I found this fungus after a couple of rainy days, in Southern California. Can anyone identify it? 69.111.189.155 (talk) 17:20, 2 December 2012 (UTC)

Possibly Sparassis crispa, known as the 'Caulifower fungus'? Mikenorton (talk) 17:33, 2 December 2012 (UTC)

Looks like its probably a species within that genus, but I dont think it's that particular species. The species in the picture looks more "curled-up" that S. crispa. I'll ask if someone at wikiproject fungi can have a look for us. douts (talk) 00:08, 3 December 2012 (UTC)

I don't think it's Sparassis crispa, but it might be a different species of Sparassis. I highly recommend posting at Mushroom Observer, there are many California residents who frequent the site and would probably be able to id it for you. Sasata (talk) 00:27, 3 December 2012 (UTC)

Actually, it doesn't look like a fungus at all, but rather like a Slime mold. Morphology of slime molds ranges widely and fantastically, as can be seen here: [[5]]. The specimen in question resembles the sixth picture from the bottom, which is, alas, not identified. Dominus Vobisdu (talk) 00:36, 3 December 2012 (UTC)

Here's a atlas with 18 pages of pictures of identified slime molds: [[6]]. If you click on a picture, and then click on the species name after the word "Title", you end up with a page full of pictures. Dominus Vobisdu (talk) 01:37, 3 December 2012 (UTC)

+1 slime mold. Especially the way it engulfs the blades of grass, rather than pushing them aside. de Bivort 03:14, 3 December 2012 (UTC)

Battery and voltage

Can you construct a battery with any combination of voltage and material? I know that certain materials have different electromagnetic forces when loaded, but you could always 'pile' them to get a higher voltage. And in the way down, you could just put a resistance to deliver a lower voltage than the output. Strangely, I am not seeing a lithium-ion battery in the form of AAA or AA battery on that market, although I would prefer it instead of alkaline AAA/AA batteries. OsmanRF34 (talk) 18:31, 2 December 2012 (UTC)

Googling "lithium-ion AAA" and "lithium-ion AA" gets me plenty of hits. They are certainly out there in the market. You don't see them more often because their voltage is too high. Lithium-ion chemistry provides 3.6V, much higher than the 1.5V expected in standard AAA and AA cells. The higher voltage might even damage the electronics. Your idea of adding a series resistance unfortunately won't work. Consider two loads, one 1MΩ load and a 1Ω load. Whatever series resistance you add to the battery will either make the current too high or too low.Dncsky (talk) 18:42, 2 December 2012 (UTC)

Yes, you are right that google gets you lots of hits, but they are by no means a replacement to the 'normal' AAA. OsmanRF34 (talk) 18:51, 2 December 2012 (UTC)

Like I explained, there's no easy way to step the voltage down. Putting a 3.6V battery in my TV remote will likely ruin it. These 3.6V batteries are for people who design their own electronics for that voltage, RC cars for example. Dncsky (talk) 19:00, 2 December 2012 (UTC)

And what's the point of making it round like an AAA battery? Couldn't they have used a flat cell-phone battery? OsmanRF34 (talk) 19:04, 2 December 2012 (UTC)

Allowing the use of AAA battery holders, I guess? I don't see any advantage in it myself. I would never buy these, since the risk of accidentally putting them in a $200 camera is too high. The vast majority of LiPo batteries are in the flat brick type. Google imaging "lipo pack" gets me the flat rectangular shapes for the first few pages.Dncsky (talk) 19:09, 2 December 2012 (UTC)

It seems as too much trouble just for keeping a minor piece. OsmanRF34 (talk) 19:28, 2 December 2012 (UTC)

They are usable in certain devices like some LED flashlights which can accept both types (although that isn't the primary reason they are made, the market is too small for that). Anyway lithium ion cylidrical cells of various sizes are commonly used in battery packs of various products like laptops, cordless drills, eletric cars, etc. The 18650 is I think the most common size but by no means the only one used. 10440 ('AAA' size) is often used in electronic cigarette. Note that many lithium ion chemistries including the most common lithium cobalt oxide are less flexible in manufacturing then the Lithium polymer battery chemistry so producing flat packs with them isn't so easy. (Anything which looks like a flat pack but has non polymer chemistry most likely just has a bunch of cylindrical cells.) AFAIK cylindrical cells are by far the most common production method for such non polymer chemistries. And when you aren't aiming for excellent packing like in phones, tablets and ultrabooks, the minor amount of wasted space isn't a big enough issue to be of concern. (There are other advantages of lithium polymer cells.) And lithium cobalt oxide still I think predominates among lithium ion chemistries (including polymer). So while lithium polymer batteries are rarely cylidrical, most lithium ion cells produced are likely cylidrical. While you can purchase individual cells included protected ones (with a small protection circuit on top), this is a market which developed for certain specialist hobbyist uses. The cylindrical cells aren't really intended for the end consumer, instead to be used in battery packs for devices or sometimes built in to the device. (And if you are using such lithium ion batteries, putting them in the wrong device and destroying the device should really only be a minor concern compared to the other precautions you have to take.) P.S. Generally speaking, it's best to avoid anyone who sells 'AA' or 'AAA' lithium ion cells. These would generally be called 14500 or 10440 by anyone who you should trust enough to buy such cells from. Nil Einne (talk) 20:18, 2 December 2012 (UTC)

If you want a voltage not available from a standard commercial battery, use a switch mode power converter. This is often done, in order to use an old battery powered device that was designed to use a battery no longer available - e.g., portable scientific instruments, multimeters, and gieger counters that were designed to use 22.5V and 45V batteries designed for 1940's and 1950's hearing aids and portable radios based on tubes instead of transistors. Such instruments were made up until the 1970's when the batteries were still available, and many are still perfectly serviceable. Because modern batteries have a much higher energy density, by using a physically smaller modern battery it is possible to fit both the battery and the switchmode converter in the space provided for the original battery. Keit 58.167.254.96 (talk) 00:02, 3 December 2012 (UTC)

Since nobody else has mentioned it, I'll point out Energizer Lithium-Iron batteries which retain the familiar carbon zinc (are they still made?) sizes, from AAA to 9 volt, I believe. [7]Gzuckier (talk) 07:01, 3 December 2012 (UTC)

As our Zinc–carbon battery article mentions, zinc-carbon batteries are still made and in fact are resonably common in some countries. Lithium-iron primary batteries are mentioned in our Lithium battery article, however the sizing issue isn't the key point. As the above discussion attests, lithium iron (rechargable) batteries are made in the same sizes. However they aren't suitable as replacement in most uses because the devices because the voltage range is quite different from what is provided by most primary cells in those sizes. (They aren't generally sold to consumers for these and other reasons.) Lithium iron batteries have a similar enough voltage range to those in common primary cells that they are generally compatible. Nil Einne (talk) 07:38, 3 December 2012 (UTC)

what are the specific enthalpies of fusion of the chocolate phase transition temperatures?

I think it will be weak compared to water, but I wonder if the phase transition energy can make up for the lack of an precise thermometer when melting chocolate (while preserving the beta crystals) for use in dessert simply by watching where the temperature rise slows down. 128.143.1.238 (talk) 20:15, 2 December 2012 (UTC)

Can you back up and tell us exactly what you're trying to do with chocolate ? If trying to melt it without burning, I recommend a double boiler. If you want a mixture of solid and liquid chocolate, toss some chocolate chips in the dessert, along with the melted chocolate. StuRat (talk) 20:17, 2 December 2012 (UTC)

I'm trying to melt chocolate without melting the beta crystals so I don't have to temper it. 128.143.1.238 (talk) 21:37, 2 December 2012 (UTC)

OK, here's an article that explains the issue: [8]. I'd simply use one of the products sold specifically for this purpose. That is, chocolate with additives so it will properly harden and form a shell, without the precise temperate control needed for 100% chocolate. (Do be sure to avoid trans-fats, though, as those are unhealthy.) One such product is Magic Shell. StuRat (talk) 22:02, 2 December 2012 (UTC)

Goggling on this question, I happened upon an answer: 93 kj/kg given on an engineering forum here. -Modocc (talk) 23:35, 2 December 2012 (UTC)

The birds and the bees

spam
The following discussion has been closed. Please do not modify it.
How is babby formed? Jessqueen99 (talk) 22:01, 2 December 2012 (UTC) See sexual reproduction, gestation, blastocyst, embryo, and fetus. StuRat (talk) 22:04, 2 December 2012 (UTC) There's also fertilization, zygote, implantation and gastrula, as well as several hundred other relevant concepts. μηδείς (talk) 02:10, 3 December 2012 (UTC) Not to mention babby.--Shantavira|feed me 09:13, 3 December 2012 (UTC) This is a popular internet meme, and should be deleted as spam. This is not an honest question, the OP is having a joke by posting this here. OP, don't do this. "How is a Babby Formed?"[[9]] — Preceding unsigned comment added by 217.158.236.14 (talk) 10:11, 3 December 2012 (UTC) Closed per IP 217's explanation. μηδείς (talk) 17:32, 3 December 2012 (UTC)

Placebo overdose

What happens when you overdose a placebo? OsmanRF34 (talk) 23:28, 2 December 2012 (UTC)

That could mean 2 different things:

1) An actual overdose, say of sugar pills. That wouldn't be terrible, unless they have diabetes, but would cause their blood sugar to spike.

2) Tell them they took too many. In this case, they could possibly will themselves into getting sick. StuRat (talk) 23:49, 2 December 2012 (UTC)

I mean 1). Under placebo I mean something without active components (that wouldn't be the case of sugar in people who have diabetes). Why wouldn't it be terrible? Placebo is something without active components, but it, for some mysterious reason, has a real effect in some people. Wouldn't a big dose of that have a bigger effect. OsmanRF34 (talk) 00:20, 3 December 2012 (UTC)

Not really, since a placebo, by definition, has no pharmalogical effect. All that occurs is a psychological effect, in other words, they think themselves into getting better so I wouldn't have thought that a bigger dose would result in a bigger effect. douts (talk) 00:25, 3 December 2012 (UTC)

I don't agree that placebos are just psychological. They have a real effect on your body, although the relationship between believing and physical effect is not well-known. OsmanRF34 (talk) 00:38, 3 December 2012 (UTC)

There have been studies showing that a larger dose of placebo has a greater effect (or, at least, the physical size of the pill does - that's all that is mentioned in our article, and I think my source is QI so that may be all they meant). I think they would need to know it was "an overdose" - obviously there is no such thing if it's just an inert substance, so it can't be a real overdose. If they did know, then a psychosomatic illness (or, more accurately, a somatoform disorder type illness) could easily result. --Tango (talk) 01:10, 3 December 2012 (UTC)

• Are you suggesting the subject has willfully "overdosed" on something he has be prescribed as a placebo? If so, are we to assume he hasn't looked on line to find out how much sucrose (or sawdust) he needs to take to kill himself? Can you be more specific? Thanks. μηδείς (talk) 02:05, 3 December 2012 (UTC)

It is quite possible to be prescribed a drug that has an active ingredient that works as a placebo, as the placebo effect is psychological. See also the nocebo effect. I don't feel it is possible for the lay person to know whether the drug is working because the brain thinks it should work, or whether there is an actual physical effect on the body. So be very careful. --TammyMoet (talk) 10:26, 3 December 2012 (UTC) See this report in the New Scientist which claims that some drugs work by amplifying the placebo effect. --TammyMoet (talk) 10:27, 3 December 2012 (UTC)

The physical size of the placebo matters? Oh no! I've been taking these really small (two millimeter long) placebo pills against catching the cold for a long time. No wonder they didn't work. I'll have to go find larger pills then. – b_jonas 23:11, 4 December 2012 (UTC)

• A beautiful example of placebo effect came up in a test of a drug, sevelamer hydrochloride, for pseudoxanthoma elasticum. [10] The patients receiving the drug experienced significant improvement. More surprisingly, the patients given the placebo did better. It turns out that the pills contained magnesium, and the placebo contained 2.5 times more magnesium than the pills with the drug. And the disease, which is caused by calcium phosphate (apatite) deposition, happens to respond well to administration of magnesium, which helps break up the aggregates and thus to dissolve the deposits. Magnesium overdose is actually possible, though unlikely, with that placebo. Wnt (talk) 02:07, 5 December 2012 (UTC)