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February 2

0 displacement photon

In a wave the particles do not displace. But according to article photon, EM waves have photons and they displace at speed of 3.0 X 108 m/s. I assume that photons do not travel but only show their energy through vibrations like ordinary matter. So only energy is travelling at the speed of 3.0 X 108 m/s. Therefore the whole universe would be filled with photons and they show different energy intensities by their vibrations just like ordinary matter. I think all should consider this. So do photons actually displace? User:G.Kiruthikan —Preceding undated comment added 11:12, 2 February 2013 (UTC)[reply]

Yes, photons move. One complexity of quantum mechanics is that subatomic particles sometimes behave as particles (which do move) and sometimes like waves (which only pass through a relatively static medium). When looking at an individual photon, whose position is known, it's usually considered to be a particle. Only when dealing with light in bulk, or photons with unknown positions, do we tend to view light and photons as waves. See double-slit experiment. StuRat (talk) 16:21, 2 February 2013 (UTC)[reply]

I think you are confusing the particle-equivalent of a wave with the medium in which the wave vibrates. In the macroscopic world, we do not usually consider that there is a particle-equivalent, so there is only the medium, which does not displace as you say. But in the quantum world, the particle-equivalent (such as a photon) is entirely separate from the medium (such as an electromagnetic field). --ColinFine (talk) 00:04, 6 February 2013 (UTC)[reply]

Grapefruit powder

I regularly buy ruby red grapefruit, but find it often has powder/flakes on the skin which mess up my clothes when I peel it. What is this ? Is it pesticide, a wax added to make it shinier, or some natural coating ? StuRat (talk) 03:56, 2 February 2013 (UTC)[reply]

It's almost certainly some kind of food-grade wax, which is ubiquitously applied to commercial fruits to keep them looking pretty on the shelves. This google search: [1] turns up plenty of relevant manufacturers thereof. --Jayron32 04:45, 2 February 2013 (UTC)[reply]

OK, assuming it's wax, how can I peel a grapefruit without it making a mess ? StuRat (talk) 05:42, 2 February 2013 (UTC)[reply]

Wash it in plain water and a soft scrub brush? --Jayron32 05:56, 2 February 2013 (UTC)[reply]

There's also simply yeast which is found on the skin of fruit like grapes. You'd have to post a picture. μηδείς (talk) 05:25, 2 February 2013 (UTC)[reply]

If it's wax, warm it with your hands so it becomes pliable, not flaking. Not that we can tell. μηδείς (talk) 05:56, 2 February 2013 (UTC)[reply]

That doesn't seem to happen. So, if it's wax, it must have a high melting temperature, as it stays hard at body temp. This is in contrast to the wax applied to cucumbers, which leaves me feeling like I've been "slimed". StuRat (talk) 06:01, 2 February 2013 (UTC)[reply]

If it isn't wax, I'm inclined to agree with Medies's idea that this is yeast. Yeast is otherwise completely harmless, it's simply everywhere, and it tends to grow and multiply in places where conditions are right; the outer skin of fruits seems a great medium for yeast: the fact that yeast is so abundant on the outer skins of fruits is what makes applications like wine and cider possible. Now, the acidity of citrus should kill the yeast once exposed to the juice, but the skins aren't that acidic, and its like a decent medium to grow yeast. It bears repeating that such yeast is normal, ubiquitous, and harmless, though if it bothers you running it under tap water for a few seconds and a gentle rub with a rag or brush should take care of it. --Jayron32 06:19, 2 February 2013 (UTC)[reply]

OK, I'll try rinsing it off with tap water, then. StuRat (talk) 06:50, 2 February 2013 (UTC)[reply]

Most fruit, especially ones with wrinkled or textured skins, should be rinsed/washed. Besides stuff like wax and pesticide residue, bacteria such as E. coli can grow and proliferate. I'm not claiming anything special about the fruit - bacteria can grow practically anywhere - it's just that fruit is often eaten raw and industrial washing is... spotty at best. The situation during harvest may also be quite unhygienic. Matt Deres (talk) 21:45, 2 February 2013 (UTC)[reply]

I always wash fruit if I eat the skin, like with grapes, but not when I toss the peels out, as in grapefruit. StuRat (talk) 23:40, 4 February 2013 (UTC)[reply]

It could be shellac, which won't melt and will flake. In the US the box has to say what the fruits are coated with, so see if the retailer will let you look at the box. Ariel. (talk) 18:57, 3 February 2013 (UTC)[reply]

Sounds likely. How do I remove it without making a mess ? StuRat (talk) 16:52, 6 February 2013 (UTC)[reply]

Chemistry question

which of the following contains both ionic and covalent bonds? 1. NaOH 2.HOH 3.C H Cl 4.CO 6 5 2 — Preceding unsigned comment added by 37.228.104.230 (talk) 06:23, 2 February 2013 (UTC)[reply]

Please do your own homework.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. --Jayron32 06:24, 2 February 2013 (UTC)[reply]

Also, what are you trying to list after CO ? The numbers 6 5 2 alone are meaningless to me. StuRat (talk) 06:48, 2 February 2013 (UTC)[reply]

Looking at the wikicode, I'm not sure if 652 is supposed to relate to the question. May be some sort of signature or just erroneous typing. Nil Einne (talk) 19:44, 2 February 2013 (UTC)[reply]

Well often here on Wikipedia you can find articles on chemical formulae by typing them in. You will find NaOH, HOH perhaps CHCl3 but perhaps your formula is different. CO leads to a disambiguation page, and you would have to pick Carbon monoxide. check your source to see if you have lost digits. (I dont mean toes I mean subscripts as in H₂O. Graeme Bartlett (talk) 09:58, 4 February 2013 (UTC)[reply]

Lime burning

Is it possible to make quicklime out of finely powdered calcium carbonate (such as that produced by chemical precipitation)? Or is there a minimum particle size below which it will get blown back out of any existing kiln? I know that a rotary kiln can process fine particles, but how fine is too fine? 24.23.196.85 (talk) 07:22, 2 February 2013 (UTC)[reply]

Anybody? 24.23.196.85 (talk) 04:43, 4 February 2013 (UTC)[reply]

Well what scale do you want to make it? Do you just want a few grams, a kilo, do you want to make tons or kilotons? Graeme Bartlett (talk) 10:02, 4 February 2013 (UTC)[reply]

Industrial scale -- the idea is to use the CaCO3 produced during the regeneration of caustic solution after the latter has been used for extraction of an acidic substance. I'm flowcharting a chemical plant in my spare time, and I want to make it as environmentally clean as possible. 24.23.196.85 (talk) 00:11, 5 February 2013 (UTC)[reply]

In quicklime, you'll see that the most common prodction is by thermal decomposition of calcium carbonate, just as you propose. I'm thinking that the key point is whether there is some particle size that is too small to be processed in a rotary kiln. I would think this depends on the design and process settings of the kiln. In principle, there is no minimum size, but once the particles are small enough to be subject to Brownian motion, the process would become impractically slow. If that's the case in your charted plant, you should consider some other way of heating the quicklime, preferably one that doesn't disperse the powder into air.--Wcoole (talk) 21:40, 6 February 2013 (UTC)[reply]

Thanks, Wcoole! Does it make a difference if the limestone powder is wet (50-75% moisture content)? Because that's the case for limestone powder obtained by chemical precipitation such as regeneration of caustic solution. 24.23.196.85 (talk) 02:12, 7 February 2013 (UTC)[reply]

Why do tortoises live so long?

Why do (some) tortoises live so long relative to other species, with some of them living 150 years or more? Thank you. Futurist110 (talk) 07:31, 2 February 2013 (UTC)[reply]

Well, part of it seems to be a slow basal metabolic rate. All things being equal, the slower the metabolic rate, the longer it takes for some types of damage, like oxidation damage to DNA, to accumulate to fatal levels. See free-radical theory of aging. StuRat (talk) 08:04, 2 February 2013 (UTC)[reply]

Other factors scientists are researching include DNA Damage Response and Repair Mechanisms. ~Eric F 74.60.29.141 (talk) 08:10, 2 February 2013 (UTC)[reply]

I am tempted to make the wild speculation here that as random deleterious mutations accumulate over pre-reproductive lifespan, just so many mutations must be "excreted" from the genome via natural selection, or else the species would be overwhelmed and lost. It would seem to follow that a species must have either a good DNA repair, a short lifespan, or vigorous selection in order to survive... but this does not mean that the DNA damage would necessarily have to kill the individual, though it could, of course. Wnt (talk) 19:06, 2 February 2013 (UTC)[reply]

Because they are stupid and eat grass. μηδείς (talk) 21:45, 2 February 2013 (UTC)[reply]

Looking at it the other way, evolution wouldn't give any advantage to turtles who didn't live a long time, in that it takes a long time to harden the shell; any turtle whose natural life span was like a year after their shell had hardened would be at a disadvantage of having gone to so much effort for so little benefit. So the only turtles you'd see after their evolutionary niche had stabilized would be ones who live a very long time. Gzuckier (talk) 23:15, 2 February 2013 (UTC)[reply]

That's spurious reasoning; you could make the same argument that all animals should be long-lived. Also, why do you think it takes a long time to harden their shell? Even little turtles have nice hard shells; it hardly takes decades to form. If you don't know anything regarding a question, it would be best not to pretend that you do. There's good (sourced) stuff up above. Matt Deres (talk) 01:42, 3 February 2013 (UTC)[reply]

The spurious reasoning would be that they have better DNA repair; you could make the same argument that all animals should be long-lived by evolving the same mechanism. Your extension to other animals would seem to be reasoning from the axiom that turtles don't take longer than a normal reptilian lifetime to form shells, based on observations of little turtles; little turtles don't live that long, you'll note. Whereas, regarding somewhat larger desert tortoises, "Their shells become essentially incompressible (within 2% of complete shell inflexibility under a moderate force of 11.2 gm/mm²) by the age of about 11 years and a size of about 110 mm MCL." [2] (emphasis mine). Prior to my previous answer I had, of course, investigated all the Wikipedia articles on turtles, tortoise, turtle shells, plastrons, carpaces, etc., as well as all that google would deliver in order to bolster my memory of the slow ossification of turtle shells, and found only this source; at the time I didn't feel it directly relevant enough to cite, but I didn't expect the Spanish Inquisition. Gzuckier (talk) 02:48, 3 February 2013 (UTC)[reply]

Now if only parrots slowly grew a protective shell....Gzuckier (talk) 07:17, 3 February 2013 (UTC)[reply]

Invention v/s Discovery

Invention An invention is a unique or novel device, method, composition or process. It may be an improvement upon a machine or product, or a new process for creating an object or a result. An invention that achieves a completely unique function or result may be a radical breakthrough. Such works are novel and not obvious to others skilled in the same field.

Discovery Discovery is the act of detecting something new, or something "old" that had been unknown. With reference to science and academic disciplines, discovery is the observation of new phenomena, new actions, or new events and providing new reasoning to explain the knowledge gathered through such observations with previously acquired knowledge from abstract thought and everyday experiences. Visual discoveries are often called sightings.

Now question is , We all know that automobile Inventor Ferdinand Verbiest,If a new BMV car come in market then what it called Invention or Discovery. — Preceding unsigned comment added by Sanilblaze (talk • contribs) 09:01, 2 February 2013 (UTC)[reply]

It would definitely be called an invention. Maybe if there's some new physical principle involved it could be a called a discovery. but just a car is definitely an invention. 178.48.114.143 (talk) 09:34, 2 February 2013 (UTC)[reply]

[edit conflict]

Neither, it would be a replica or an adaptation of his innovation. Note however, the steam "car" designed by Verbiest in 1672 was a toy for Kangxi Emperor of China, and would not scale-up to an operational "auto-mobile" as we know it. It is debatable that Verbiest "invented the automobile".

Verbiest did not think, either, that he had invented the automobile. In all humility he thought of his machine as "a method of movement" for which "other diverting applications are easily contemplated."

—Witek, jointly publ. by Institut Monumenta Serica, Sankt Augustin ... Ed. by John W. (1994). Ferdinand Verbiest : (1623 - 1688) Jesuit missionary, scientist, engineer and diplomat. Nettetal: Steyler Verl. p. 268. ISBN 3805003285.{{cite book}}: CS1 maint: multiple names: authors list (link)

~E:74.60.29.141 (talk) 10:00, 2 February 2013 (UTC)[reply]

Perhaps there is a Platonic realm of new car designs just waiting to be discovered. Gandalf61 (talk) 10:04, 2 February 2013 (UTC)[reply]

Perhaps the fact that we can compare the old car to the new car and show it is improved itself implies there is the objecive image of an ideal car somewhere - acceleration tends to infinite, fuel used tends to 0, etc ---- _nonsense ferret 14:20, 2 February 2013 (UTC)[reply]

Intuitively, it seems like it should be obvious that DNA sequences and Penrose tilings are discovered, rather than invented, no matter what the patent or copyright offices may say about the matter. The radio spectrum is something to be discovered, even if the particular arrangement of readily available parts in a specific radio is an invention. And the idea of having, say, a "steam powered car" or "gas powered car" or "nuclear powered car" should be something discovered, or simply an obvious combination of words, rather than an invention, though actually making it is an invention. So I would think that the essence of invention is taking specific fallible, real-world components with real world limitations and variances and tolerances and coming up with a way to do something with them, whereas the essence of discovery is to understand some universal standard from the Platonic realm or from the common legacy of the human race (genes, types of minerals, etc.). A person from an alien race on an alien planet should discover the same things we do, but invent different things. The Platonic ideal of a car should be determinable by doing archaeology on planets of many different stars to find common features. But this is all, alas, a question (or hypothesis) rather than an answer; I'm not even sure how to find reliable sources for any of this. (I should note that there's some tension expressed in the "or" above - I cannot exclude discovery of a specific legacy item though, unless we want to say that Columbus invented America. But there's a difference between discovery of America, which aliens could only make by travelling here, human genes that they can only discover with a sample, etc. and discovering fire or powered flight, which they could do at home) Wnt (talk) 18:45, 2 February 2013 (UTC)[reply]

SHD distribution on optical high speed networks

hw SHD distribution on optical high speed networks takes? — Preceding unsigned comment added by 223.228.36.112 (talk) 10:18, 2 February 2013 (UTC)[reply]

This question cannot be answered as it does not make sense. Presumably SDH is Synchnonous Digital Hierachy, but what is hw? Takes what? Your IP address gelocates to Bengalore India. You need to take care to write sensible and complete English if you want a useful answer. Keit 124.182.26.251 (talk) 15:06, 2 February 2013 (UTC)[reply]

I presume hw is how. I don't think takes is really the best word for what the OP is saying, probably instead something like 'works' or 'is used' or 'is done. Nil Einne (talk) 19:40, 2 February 2013 (UTC)[reply]

Or write the question in your native language, and we will translate for you. StuRat (talk) 16:13, 2 February 2013 (UTC)[reply]

Thanks

Thanks to all those who answered my January 28 question "Why don't the the sunrise and sunset times go the other way at the solstice?" [3] which has now disappeared into the archives. The answers were very informative. Richerman (talk) 12:57, 2 February 2013 (UTC)[reply]

You're welcome. StuRat (talk) 16:14, 2 February 2013 (UTC)[reply]

Historical election to fellow of RAeS

I am helping a new editor research the biography of Roy Chaplin. Is the process for the election to a fellow of the Royal Aeronautical Society (RAeS) in 1939 documented anywhere? I suspect that one of Chaplin's papers, presented to the RAeS in 1939, was used as part of such an election process. Are fellowship elections to Royal Society's gazetted?

I see a recently example where it was noted in Aviation Week & Space Technology - but that only started in 1947 so not much help sorry. ---- _nonsense ferret 14:24, 2 February 2013 (UTC)[reply]

I've also searched the Gazette for you, but the only reference I can find to his name is the OBE. I did find a couple of other newspaper references so I've added those to the article in userspace, hope that helps a little bit ---- _nonsense ferret 14:58, 2 February 2013 (UTC)[reply]

There is a reference to "1960 R.H. Chaplin (Fellow)" as a RAeS Silver Medallists [4] which at least seems to show he was already a fellow, not sure if that helps ---- _nonsense ferret 15:52, 2 February 2013 (UTC)[reply]

I drew a blank too in the gazette. I'm not even sure whether fellowship ~~awards~~elections are gazetted. Your RAeS source does narrow down the time-frame of Chaplin's fellowship election to between 1939 and 1960 and additionally confirms his 1960 silver medal award, thank you. Thank you too for the additional further reading --Senra (talk) 16:13, 2 February 2013 (UTC)[reply]

Ground state and vacuum state

Are these synonyms? If not, what is the difference? The articles aren't clear on the point. FT2 ^{(Talk | email)} 18:32, 2 February 2013 (UTC)[reply]

No. The vacuum state is the ground state of a quantum field. Every quantum system has a ground state (its lowest-energy state), but only a field has a vacuum state. Looie496 (talk) 18:41, 2 February 2013 (UTC)[reply]

Concise, thank you! Can you elaborate a bit and (perhaps equally concisely) clarify the significance of the term "quantum system" (as opposed to quantum field/fields)? Thanks FT2 ^{(Talk | email)} 20:15, 2 February 2013 (UTC)[reply]

A quantum system is any system that obeys quantum behavior (Specifically, it obeys quantum commutation rules for the system coordinates and their canonical momenta). A quantum field is a quantum system with infinite (In fact uncountably infinite) degrees of freedom - that's what the word field mean. The simplest fields - scalar fields - have one degree of freedom for each point in spacetime. Note that spacetime has uncountably infinite points. That's in opposition to particle quantum systems (AKA first quantization) which have finite number of degrees of freedom - three space coordinates for each particle (Or countably infinite in case you have infinite particles). Dauto (talk) 01:26, 3 February 2013 (UTC)[reply]

February 3

Gravity in a bounded universe

The divergence of the gravitational field is equal to the mass density, which is non-negative everywhere and positive in some places. The net divergence in a bounded system must be zero. Doesn't this mean that the universe is unbounded, and thus the curvature must be non-positive? For that matter, even if it is, wouldn't an approximately even mass distribution result in an unbounded gravitational field?

My best guess is that the mass density of a vacuum is negative. Is this correct? — DanielLC 05:44, 3 February 2013 (UTC)[reply]

Your first statement is only correct within Newtonian gravity which is not applicable to the universe as a whole. Dauto (talk) 15:37, 3 February 2013 (UTC)[reply]

You are right that the mass density of vacuum is negative (in sense that it produces repulsion instead of attraction), while the energy density is positive. Ruslik_Zero 19:06, 3 February 2013 (UTC)[reply]

What does it mean for energy density to be positive? If you change the potential energy of every state under quantum physics, this does absolutely nothing. I've been told you need general relativity to find any sort of energy density of the vacuum. — DanielLC 23:21, 4 February 2013 (UTC)[reply]

while we're on the subject of turtle evolution

We've all seen the videos of the little turtle hatchlings crawling toward the sea as fast as they can while sea birds etc feast on them (also noted in our turtle article); why wouldn't evolution push them all to the point where they lay their eggs like 2 feet above high tide line? Particularly when I notice the aforesaid turtle article notes that turtle eggs kept moist do better than those kept drier? Gzuckier (talk) 06:49, 3 February 2013 (UTC)[reply]

Unless I'm missing something here, you have pretty much answered your own question. Above high tide line - less moist. At high tide line just moist enough. Richard Avery (talk) 08:00, 3 February 2013 (UTC)[reply]

This article suggests that predation is a likely controlling factor with the optimum nest position being close but not too close to the water's edge, I presume that by widening the strip within which nests may be located, the predator's job is made more difficult. Mikenorton (talk) 08:10, 3 February 2013 (UTC)[reply]

Also, predation can help eliminate defective genes, by removing the least fit individuals. StuRat (talk) 08:16, 3 February 2013 (UTC)[reply]

Another factor to consider is that nests which are placed too close to the high tide line run the risk of being drowned, and as noted in the "cape" episode of David Attenborough's Africa series, should the nest be flooded before the eggs hatch, they won't survive. douts (talk) 14:15, 3 February 2013 (UTC)[reply]

Light bulbs. halogen --> LED

I have 81 50-watt halogen downlighters GU10 ES50 which link to 240v - 12v transformers. Can I get something which will provide the same amount of light in one LED bulb? Kittybrewster ☎ 10:45, 3 February 2013 (UTC)[reply]

Assuming you mean to replace EACH 50 W halogen light with one LED fitting, the answer is yes. Have a look at this: http://www.siliconchip.com.au/Issue/2013/February/Replace+Your+Halogen+Down-lights+With+LEDs. Ratbone 124.182.26.251 (talk) 10:59, 3 February 2013 (UTC)[reply]

Yes. Good. Warm white, daylight or pure white? 2w 3w 4w or 5w? Is there a reference for these lights at a UK supplier?Do they need a 12w LED Driver Transformer for MR16-MR11-G4 LED Light Bulb by Long Life Lamp Company? Kittybrewster ☎ 15:19, 3 February 2013 (UTC)[reply]

I've replaced some GU10 12V halogens with LEDs. They run on 12V AC (IIRC, they have a built-in rectifier). For some reason they don't have the halogen-equivalent wattage marked. However, LEDs about about 3 times as efficient as halogens, so I'd go for about 15W. The lamps are marked as non-dimmable; if you want to dim them you might need to buy a ballast. CS Miller (talk) 20:02, 3 February 2013 (UTC)[reply]

The best answer is 'may be'. Presuming you don't mean to replace anything in the fitting, replacing 12V halogens with LED equivalents can be problematic. You can find many complaints from a simple search, some people recommend just replacing them with main voltage ones. The problem is in the transformer, the electronic transformers (switched mode power supply) commonly used may be designed for 50W bulbs and may not like the far lower voltage, some may not work at all. Even if they do work, you sometimes get flickering due to an interaction between the switch mode power supply on the bulb and the switch mode power supply in the fitting. The output from the SMPS is most likely not a simple 50 or 60 hz AC since it doesn't matter to the halogens. More reliable manufacturers often have long lists of transformer compatibility charts for their lights. In the unlikely event your bulb uses a simple transformer, I would guess you shouldn't have problems.

However although not commonly discussed, there is an advantage to the 12V namely safety. In fact I read about [5] [6] which shows even someone like Philips can screw up their design. I personally chose GX5.3 12V as opposed to GU10 240V despite the issues because I prefer cool white bulbs (at least 5000K and preferably higher) and it's not that easy to find high CCT bulbs from reliable manufacturer with a high CRI (even when it comes to the raw LEDs they're far rarer then low CCT high CRI). However I did encounter flickering from some of the bulbs I purchased from AliExpress using Sharp COBs. I believe the ones that flicker for me use a boost drive as the LED forward voltage is above 12V (some of the LED dies are series) which highlights I guess another unfortunate fact, a number of COBs and LED arrays do have a forward voltage above 12V because they're targeted at the line voltage market where it's an advantage since the buck driver doesn't have to reduce the supply so much. One intermediate option between going main voltage is to keep the fitting but replacing the transformer with one designed for LEDs (or better both LEDs and halogens) source from a reliable manufacturer. Of course you could replace the whole fitting with an LED one, I didn't do that here because what's available seems rather poor and limited, even before taking in to account my preferences but things may be better in the UK.

The other consideration is the design of your fitting. If the bulbs are enclosed or recessed in the wall, you're far more likely to have a problem since LEDs really don't like to get hot. For the same reason, 50W halogen equivalent is difficult for a bulb that sized. Some of the Philips GX5.3s (and I think GU10) even have a fan. (In my case I purposely overlighted the area so it doesn't matter if they aren't so bright.) This also depends on your requirements. If you want a high CRI low CCT light you'll need a more powerful bulb since both high CRI and low CCT generally means a lower luminous efficacy. Even when it comes to similar CRI and CCT, LEDs are still rapidly evolving so it depends significantly on the LED used. (As well of course on the efficiency of the driver.)

Nil Einne (talk) 05:31, 4 February 2013 (UTC)[reply]

P.S. From a quick search, one more problem you may have is I don't think GU10 12Vs are particularly common. AFAIK, GU10s are usually main voltage and GX5.3 are used for 12V in the MR16 world. Given the similarity, for Chinese manufacturers from AliEpxress you may be able to get them to make some GU10 12Vs easily if you're buying a decent quantity perhaps 10-20. For well known brands, you'll just have to use what's available. Nil Einne (talk) 05:51, 4 February 2013 (UTC)[reply]

Male vs female pain

I heard that females are more tolerant to pain than men, because men have more pain receptors. It's linked to the Y chromosome. Is this true?Dbjorck (talk) 08:30, 3 February 2013 (UTC) Copied from Talk:Nociception#Male vs female pain 10:54, 3 February 2013 (UTC)[reply]

In Sexual dimorphism it says generally females feel pain more than males. I believe I read somewhere this applies even to babies so it is not something that is just learnt. This makes sense really, males fight more and pain that distracted would be a disadvantage. Dmcq (talk) 14:07, 3 February 2013 (UTC)[reply]

This is like asking "is the sky brown?" Common sense should be more than enough to tell you it's blatantly false, and that women are far more sensitive to pain. In case you don't believe common sense, here is an article that quotes a scientific paper. Here is an article from Scientific American. "The reason for this is not known, Fillingim said. Past research suggests a number of factors contribute to perceptions of pain level, including hormones, genetics and psychological factors, which may vary between men and women, Fillingim said. It's also possible the pain systems work differently in men and women, or women experience more severe forms of disease than men, he said." --140.180.247.198 (talk) 17:56, 3 February 2013 (UTC)[reply]

Googling "number of pain receptors" returns some pages, amongst a lot of junk, that indicate both sexes have about the same number of pain receptors per unit area of skin. Since men are bigger and have more skin area than women, they have more pain receptors. However, this does not mean more sensitivity, nor less.

The study reported in Scientific American is deeply flawed, as reading the attached reader comments shows. To measure something, whether it is magnitude of pain, volts in an electric circuit, or the weight of a parcel, you need a measurement system that has appropiate resolution, and calibration. They measured by asking patients to rate their pain on a numerical scale, 0 = no pain, to 10 = worst pain imaginable. That's plenty of resolution, probably too much, but there is no calibration. Who is to say whether I can imagine a pain more severe than you? Perhaps I fell off a ladder, breaking my hip. Perhaps you were very sick with an intestinal blockage. Perhaps we both never before had any pain worst than childhood accidents. Perhaps I have a more vivid imagination. Perhaps I only think I do. A better question might be "What is the severity of your pain, 0 = no pain, 1 = I have pain, but I am happy to ignore it, 2 = the pain constantly intrudes on my consciousness, 3 = I cannot think or function at all with this level of pain 4 = I want to die" Since the brain has evolved over a very long period of time to prioritize what gets presented to consciousness with a well defined structure, this would give at least some calibration.

It should also be noted that we have more than one system for sensing pain. There is a specific nerve network ending in pain receptors in the skin. There is a quite separate system of nerves ending in pressure sensors in the digestive system. The brain interprets excess pressure as pain. It may well be that men are more sensitive than women for skin pain, and women more sensitive to gut pain. Or vice versa. Or some other combination. By not recording and accounting for this, the study repoted in Scientific American is futher flawed.

Not only is the preception of pain severity, and the degree which an individual reports it (two different issues confounded in the SA study) culturally influenced ("real men don't cry"), it depends on state of mind. It is well known that humans will put up with almost anything if they have the right state of mind, and/or they can see a light at the end of the tunnel. In World War 1, for example, General Monash was able to inspire troops to put up with hardships unimaginable to folk that have not served in a battle. After my wife had an operation, the nurse came around and asked her to rate her pain. On being told it was as bad as anything, the nurse gave her a narcotic and valium. A little later, my wife asked for more. But the nurse sized her up and said she could have a half dose of narcotic and no valium. My wife protested, saying the pain was again bad. The nurse replied, "You should expect some pain, you are obviously well aware of your surroundings now. If I keep giving you valium, you will become addicted." Whereupon my wife decided the pain was not so bad after all, and talked to me brightly about all the flowers and phone calls she had received from her work mates. — Preceding unsigned comment added by 124.178.53.46 (talk) 01:36, 4 February 2013 (UTC)[reply]

Wickwack 121.215.57.3 (talk) 01:03, 4 February 2013 (UTC)[reply]

Re calibration: Remembering my psych grad school daze, if people are provided with defined end points to a scale, they can be relied upon to scale stimuli very nicely (usually on a log scale) and repeatably, whereas in the absence of such defined end points the reported intensity wanders all over the scale between different subjects, or the same subject various times. Of course, we weren't paining people (that would be a creepy experiment; "Now, call this pain 10 out of 10" and then do ???), but the finding was so universal that I'd be really surprised if pain receptors were any different. As for the other factor, yeah, everybody who is familiar with dogs or kids has probably seen them smack into a wall full tilt or something when playing and laugh it off, while when they're looking for pity the teeniest scratch or bruise will cause copious agony. Gzuckier (talk) 02:49, 4 February 2013 (UTC)[reply]

True. I probably should have said the SA study had poor calibration at the top end, rather than saying there was no calibration. The top end calibration was poor because it requires imagining the most severe pain, and that depends on experience. Wickwack 60.228.245.239 (talk) 03:08, 4 February 2013 (UTC)[reply]

I admit the Scientific American article was not the greatest example. Nevertheless, there is abundant evidence that men have a greater pain tolerance than women, and none at all for the opposite viewpoint. This literature review, for example, describes studies that use brain imaging to measure human pain response. Differences in pain tolerance have been unambiguously found in both humans and animals. In humans, these differences appear in subjective questionnaires like the SA study, behavioral tests such as Lowery et al, and PET brain scans such as Paulson et al. In animals, the differences appear in behavioral observations and brain measurements, like measurements of stress-induced analgesia. By "differences", I mean that males have unambiguously higher pain tolerance than females, and not the other way round. This other review article claims that the results of brain imaging studies are mixed, but is nevertheless unambiguous in its conclusion: "Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances." Of course all of these studies, just like all of science, are limited or flawed in some way. Even so, they're much more trustworthy than WP:OR based on one anecdote about WWI and another anecdote about somebody's wife. --140.180.247.198 (talk) 02:58, 4 February 2013 (UTC)[reply]

The study quoted in our Pain threshold article is Sex Differences and Incentive Effects on Perceptual and Cardiovascular Responses to Cold Pressor Pain by Daniel Lowery, MA, Roger B. Fillingim, PhD and Rex A. Wright, PhD. Alansplodge (talk) 19:23, 4 February 2013 (UTC)[reply]

D'oh! Already linked above - sorry 140.180! Alansplodge (talk) 19:25, 4 February 2013 (UTC)[reply]

Wasn't there also some surprising finding, in the last few years, that certain painkillers were ineffective for women while being very effective for men? I recall it being taken as further evidence that the pain pathways and natural painkilling mechanisms were different in men and women. It also was taken as a cautionary tale of the dangers of narrow samples being used in drug trials and taken as representative of the wider population. Ring any bells for anyone? 86.163.209.18 (talk) 22:06, 4 February 2013 (UTC)[reply]

Black holes: Why the most complex objects in the universe?

Andrew Strominger (and others) state that event horizons are governed by a strikingly simple set of quantum laws which implythat black holes are at once the simplest and most complex objects in the physical universe. I understand the first part, as they are defined by three parameters only - mass, electrical charge and angular momentum (however, this is derived from general relativity, not from quantum laws, isn't it?) But why are they the most complex objects? I understand it has to do with Black hole thermodynamics and the Black hole information paradox, but still fail to explain, not the least in confusion how the concepts entropy, information and complexity interact in this case. --KnightMove (talk) 13:09, 3 February 2013 (UTC)[reply]

Utter speculation on my part, but I'm guessing that if you tried to map the event horizon, you might end up with some ridiculously, fractally wiggly line, just like the Mandelbrot set, another surprisingly-complicated system with a surprisingly simple definition. —Steve Summit (talk) 13:41, 3 February 2013 (UTC)[reply]

It's probably because black holes have the largest physically possible entropy for an object their size (Bekenstein bound). -- BenRG (talk) 06:15, 4 February 2013 (UTC)[reply]

This article exactly demonstrates my confusion: This article uses the terms entropy and information as straight proportional almost-synonyms, while they are generally regarded as almost-opposites and an increase in entropy means a decrease in information. This leads to the next ??? when entropy is supposed to increase in the universe, while information supposedly cannot decrease... --KnightMove (talk) 10:53, 4 February 2013 (UTC)[reply]

Yes, the word information is used inconsistently. It means "the logarithm of the number of equiprobable states", but they may be talking about different states in different circumstances. If they're counting indistinguishable microstates, it's the same as entropy. If they're counting phase space volume, it's conserved. If they're counting distinguishable macrostates weighted by the number of indistinguishable microstates in each one, it's the sort of information you're thinking of. -- BenRG (talk) 17:16, 4 February 2013 (UTC)[reply]

antimatter

Is there any likelihood that there is a way to change matter to antimatter using a relatively small amount of energy so that you can use matter-antimatter interaction to gain energy? Bubba73 ^{You talkin' to me?} 14:17, 3 February 2013 (UTC)[reply]

What do you think, Bubba? Such a thing would make possible a perpertual motion machine, as no doubt you have realised. Floda 120.145.46.100 (talk) 14:46, 3 February 2013 (UTC)[reply]

How would you make a perpetual motion machine with this? What Bubba suggested converts matter into energy, so you would need to continually supply matter (fuel) to keep the machine running. - Lindert (talk) 14:54, 3 February 2013 (UTC)[reply]

(ec) No, it would not make a perpetual motion machine possible. What you gain in energy, you lose in annihilated matter and antimatter, via E=mc². There may be other reasons why this is impossible, but neither the first nor the second law of thermodynamics stands in the way. --Stephan Schulz (talk) 14:59, 3 February 2013 (UTC)[reply]

Erk! You are right. Floda 121.215.4.176 (talk) 16:13, 3 February 2013 (UTC)[reply]

My impression is that a very small black hole is just such a catalyst, but I don't know if that is actually true. Wnt (talk) 15:11, 3 February 2013 (UTC)[reply]

A very small black hole might conceptually be able to convert matter to energy efficiently - you feed the matter into the black hole at the same rate that it is dissipated in the form or Hawking radiation. However, this is highly unstable. The smaller the black hole becomes, the faster its rate of evaporation. So you need to feed it more matter to make it cool down. If the math at Hawking radiation holds up, a 200 ton black hole will produce 7 billion gigawatts. You need to feed the mass equivalent of that into the black hole to keep it stable, against that radiation pressure. And the major snag here is that we would need a good theory of quantum gravity - I doubt that general relativity scales down to quantum sizes. --Stephan Schulz (talk) 16:24, 3 February 2013 (UTC)[reply]

Well, the problem isn't really so much keeping it stable as getting over that hump to create a synthetic black hole in the first place; after that you can bulk it up until it converts energy at a sedate rate and is less likely to explode suddenly if the computer crashes. And yes, the question of what the smallest possible black hole looks like is of the greatest interest, since it is at once the greatest obstacle and, if it can actually be created, perhaps the greatest opportunity, to do the conversion at that step of creation only, never having a black hole that has any possibility of slipping away and eating the Earth. Wnt (talk) 17:07, 3 February 2013 (UTC)[reply]

If one had access to a smallish black hole (I'm not talking a furiously-Hawking-radiating size, necessarily, either, just conveniently smaller than a solar or planetary mass) it would be a dandy source of energy. Throw any old matter that you like into it, and you'll get a significant fraction – typically at least 10%, and possibly upwards of 40% depending on the circumstances – of the mass-equivalent energy radiated back out. (Frictional heating makes infalling matter hot. Like, really hot.) This isn't Hawking radiation, this is just plain old blackbody emission from still-outside-the-event-horizon matter making up the accretion disc. Black hole#Accretion of matter touches on this point. (Science fiction buffs may recognize this concept from Imperial Earth, in which Arthur C. Clarke used small black holes in this way to power interplanetary ships.) TenOfAllTrades(talk) 19:33, 3 February 2013 (UTC)[reply]

Guys, you seem to be missing the big picture here: the question is one step away from saying "Can we convert matter into energy according to e=mc^2, using a relatively small amount of energy"? If we do take the "logical" next step in the question (use the antimatter to gain energy), that's all this is equivalent to. In other words, using up matter directly, for its high theoretical energy yield, using relatively little energy. Is such a thing theoretically possible? Is it possible by the means suggested, of turning the matter into antimatter first, using relatively little enrgy? 178.48.114.143 (talk) 15:32, 3 February 2013 (UTC)[reply]

Well, that's what I described with the small black hole, but I suppose I should have clarified. If you make a very small black hole, smaller than a primordial black hole, then it will evaporate in a very short time by Hawking radiation. So in theory, if a black hole has only mass, charge, and spin that is, you can cram matter down its gullet (emphasis on the cram, as we're speaking of something the size of a subatomic particle, perhaps) and what comes out may be particle pairs, matter + antimatter, that can annihilate and produce light. But ... I don't know for sure myself, what with all the talk of some kind of conservation? of physical information in the Hawking radiation, whether there could be some sort of 'matter-ness' in the black hole you feed this way after all that would somehow foul the scheme. Wnt (talk) 16:16, 3 February 2013 (UTC)[reply]

I was talking to a friend who was wondering about getting energy from matter-antimatter interaction. I asked "where do you get the antimatter?". I said that it takes more energy to make antimatter than you would get out. He wondered if it was possible to convert regular matter to antimatter and use it, with a net gain in energy. I doubt it, but I don't know. Bubba73 ^{You talkin' to me?} 16:39, 3 February 2013 (UTC)[reply]

I don't think the question is one step away from saying "Can we convert matter into energy according to e=mc^2, using a relatively small amount of energy" ? The question is much more fundamental. Can you change the sign of the charge of a particle. Sean.hoyland - talk 16:48, 3 February 2013 (UTC)[reply]

Nay, it's not changing the charge. For example, if you dump only protons into a mini black hole, it will quickly take on a positive charge (one of the three properties they do have by all accounts) and repel taking up more; when a virtual pair becomes Hawking radiation it will be the negative one that drops in the event horizon and the positive one that goes away, most likely, until the balance of charge is restored. Wnt (talk) 17:03, 3 February 2013 (UTC)[reply]

The OP's question is "Is there any likelihood that there is a way to change matter to antimatter" Sean.hoyland - talk 17:08, 3 February 2013 (UTC)[reply]

Or "Is there any likelihood that there is a way to change matter to antimatter with using a minimal amount of energy", where minimal amount is << 2mc². ---- CS Miller (talk) 17:24, 3 February 2013 (UTC)[reply]

Right. And have it so that we can use it, e.g. not inside a black hole. Bubba73 ^{You talkin' to me?} 17:50, 3 February 2013 (UTC)[reply]

Wouldn't rotating matter in the fourth dimension make it into antimatter? μηδείς (talk) 21:24, 3 February 2013 (UTC)[reply]

Unless there's some exchange between different elemental particles, that would seem to violate Charge conservation, i.e. if an electron can be 'turned' into a positron through the fourth dimension without involving any positively charged matter, the net electric charge of the universe changes, which shouldn't happen. - Lindert (talk) 23:10, 3 February 2013 (UTC)[reply]

But charge alone isn't conserved, isn't it something like charge x mass x velocity that is conserved? You will have to forgive me, as I am totally ignorant here, but I seem to remember something like this. μηδείς (talk) 01:28, 4 February 2013 (UTC)[reply]

Charge is conserved, energy is conserved. Neither of these is necessarily violated by changing matter to antimatter, but doing that will violate conservation of baryon number. It's not clear whether conservation of baryon number is a fundamental law or just a general observation. Baryon asymmetry would suggest the latter. Someguy1221 (talk) 01:37, 4 February 2013 (UTC)[reply]

In the sense of "a black box that you push matter into, and antimatter (and some waste matter & energy) comes out" - yes, of course we can do that. Inside we'd have a fusion reactor which is converting matter into energy (and a lot of waste product) and something as described in Antimatter#Artificial_production using that energy to create antimatter. If you don't look inside the black box, it does what the OP wants - but the relatively small yield of the process means that you'd be better off just using the fusion reactor to do the work.

More directly, Antimatter#Positrons says that you can fire electrons at a small diameter gold target using a laser and get positrons out the other side - which is doing that conversion - but the amount of energy needed in the laser presumably exceeds the amount of energy you'd get by recombining positrons and electrons - or else I'd have something like that inside my electric car! So no free energy device here!

If there is a way to do this conversion cheaply, we don't know what it is because according to Antimatter#Cost, the current price to create antimatter is between $25 billion per gram (positrons) and $62.5 trillion per gram (antihydrogen). The cost of storing the stuff in any quantity would likely be off the charts!

However, the lower of those two numbers looks promising! One gram of antimatter can produce 2mc² = 18,000,000,000,000,000 Joules of energy. A KWh is 3.6MJ - so our gram of positrons makes 50,000,000,000 KWh. A KWh costs about $0.1 in the USA right now...so that's $5bn worth of electricity for a $25bn outlay...well, OK, nobody's getting rich on this anytime soon - but it's not that inefficient. A 20% efficiency would be economical for (for example) powering a car or an airplane. If you could find a way to reliably contain the stuff (and that's a huge "IF"!), you could easily store all of the energy your car would ever use in a box that might fit conveniently into the glove box and which could be installed into the car when it's manufactured! That kind of energy density would certainly be worth having.

SteveBaker (talk) 13:48, 4 February 2013 (UTC)[reply]

Assuming that such antimatter powered cars would have about the same efficiency as today's electric cars, and doing a quick back-of-an-envelope calculation (0.1-0.23 kW.h/km accroding to our article, and assuming a design life of 300,000 km), you would need about 100-200 GJ of energy, which is 25-50 tonnes of TNT. I'm not sure I want to be driving round with the equivalent of a small tactical nuclear weapon in the glove box, so the containment question is, as you say, a huge "IF". Apologies if I have made an order of magnitude error somewhere, I did the calculation rather quickly!

Equisetum (talk | contributions) 17:54, 4 February 2013 (UTC)[reply]

Yall might find Neutral particle oscillation interesting - a process by which neutral mesons do indeed (Spontaneously !) convert into their antimatter selves. Dauto (talk) 16:19, 4 February 2013 (UTC)[reply]

Basically, if there were any way of converting ordinary matter particles (protons, neutrons and electrons) into their antiparticles with a relatively small amount of energy input, it would happen spontaneously by quantum tunneling, and ordinary matter would decay into photons and neutrinos, and there would be no us. So no. -- BenRG (talk) 17:25, 4 February 2013 (UTC)[reply]

Chemistry after nuclear decay/transmutation

In most studies of nuclear decay, the atom's electron shell and what it is bound to is not considered. However, this is what I am interested in.

Consider a molecule of dimethylpropane (neopentane), that has been carefully crafted so that the central carbon is ¹⁴C, and then others are ¹²C, i.e. ¹⁴C(¹²CH₃)₄. It is observed until the central atom decays to ¹⁴N⁺, (assuming the electron ejected from the nucleus isn't captured by the shell). Thus we now have ¹⁴N⁺(¹²CH₃)₄.

My question is, is one of the methyl groups ejected by the nitrogen, to form N(CH₃)₃, (assuming that this molecule is stable)? CS Miller (talk) 16:40, 3 February 2013 (UTC)[reply]

Trimethylamine is a real and stable – though rather stinky – chemical compound. My first thought was that such a compound arising would be unlikely simply because radioactive decay is a relatively energetic process; one might expect the recoil of the newly-formed nitrogen-14 nucleus to rip it loose from any chemical compound to which it was attached. (For reference, the decay energy for carbon-14 is about 156 keV (156,000 eV), whereas typical covalent C-C and C-H bond-dissociation energies are on the order of 4 or 5 eV. While most of the beta decay energy gets carried off with the emitted beta particle and neutrino, some small fraction of it ends up with the N-14 nucleus.)

It turns out, though, that that isn't necessarily the case. Remarkably, carbon-14 decay is gentle enough (barely) that at least some of the expected derived N-14 compound may survive, under at least some circumstances. Way back in 1956, Wolfgang et al. actually did a similar experiment using C-14 labelled ethane (H₃C-CH₃), and found that 47% of the ethane molecules survived 'intact' post-decay to form the anticipated compound, methylamine: H₃C-NH₂. Whether or not this result generalizes well to the decay of neopentane, I wouldn't hazard a guess. TenOfAllTrades(talk) 17:55, 3 February 2013 (UTC)[reply]

Thank your for your speedy reply ToaT, unfortunately I don't have access to that paper. I didn't know that some of the decay energy ends up in the atom, rather than the ejected subatomic particles. Neopentane was just used as an example; I could have chosen any organic molecule. Assuming that the recoil doesn't rip the nuclide out of the molecule, am I correct to think, after the decay, the product nuclide will eject an attached group to retain a stable 8 octet?

A follow up question. If the the groups are different (say the 3rd carbon in 3-methylhexane decays), is it possible to predict what will be ejected? CS Miller (talk) 19:28, 3 February 2013 (UTC)[reply]

Tetramethylammonium, or even more complex Quaternary ammonium cations, isn't so unstable that it would be likely to fall apart (you probably have bottles of them in your shower and laundry!). It still does have a stable octet, it just also (now) has a charge. DMacks (talk) 21:32, 3 February 2013 (UTC)[reply]

Uh, tetramethylammonium is toxic and is not normally used in household detergents. Most household detergents use alkyl sulfonates, which are more effective in this application in any case. 24.23.196.85 (talk) 04:54, 4 February 2013 (UTC)[reply]

Quat-ammonium compounds are commonly found in many products for many reasons (obviously less-toxic ones often suffice). I encourage you to read our article about them to see many applications (including subarticles such as shampoo the common polyquaternium class of ingredients among others). The question was about stability vs flying apart: even the tetramethyl article's studies on toxicity are predicated on it being stable enough to study. DMacks (talk) 12:33, 4 February 2013 (UTC)[reply]

What is this crinkly wood - and why is it so?

Split wood showing crinkly grain (approximately circumferential split face uppermost, radial split face on right)

The pictured wood is from the UK, is lightweight and easily split in either plane. It is mainly pale yellow with some red streaks and is very crinkly throughout available samples. The wavelength of the crinkles is 6-7mm and their polarization is circumferential to the tree, so that the surface of radial splits is highly corrugated. No bark remains on the sample.

What is it? and why is it so?

Thanks --catslash (talk) 23:24, 3 February 2013 (UTC)[reply]

It's hard to say with certainty without knowing more about its source, but it seems to be a form of burlwood. E.g.:[7], from:[8] ~:74.60.29.141 (talk) 00:41, 4 February 2013 (UTC)[reply]

Is it perhaps from a Dutch elm diseased tree? Is Crinkley Wood near Crinkley Bottom? See also Noel's House Party --Senra (talk) 04:19, 4 February 2013 (UTC)[reply]

No, Dutch Elm disease affects the bark and the structures immediately below, the woody trunk is unaffected, apart from the fact that it becomes part of a dead tree. Elm is notoriously slow to rot, Old London Bridge sat on elm piles for 650 years. I'm old enough to remember trying to burn the damned stuff; "Elmwood burns with a churchyard mould, E’en the very flames are cold..."[9]. Alansplodge (talk) 13:12, 4 February 2013 (UTC)[reply]

'Walter' here has a theory about it. I have seen it in mature oak and olive wood. A real nuisance when you're splitting logs. Richard Avery (talk) 08:20, 4 February 2013 (UTC)[reply]

I like the "reaction wood" explanation - and (of course) we have an article about that: Reaction wood. SteveBaker (talk) 13:11, 4 February 2013 (UTC)[reply]

Perhaps that photo→ would make a good addition to the article (which could also use a citation to the certified arborist @Wavy Wood - Explained) - However, would this be WP:OR or perhaps wp:synthesis? ~:74.60.29.141 (talk) 17:56, 4 February 2013 (UTC)[reply]

Eventually found it on the web. It would have been easy to find if only I had known that it was called a curly figure. This looks very similar to mine in every particular. Apparently the cause is not known, or at least not agreed. Thanks for the suggestions though. --catslash (talk) 01:10, 7 February 2013 (UTC)[reply]

February 4

Acupunture for Cerebral Venous Thrombosis

request for medical advice

The following discussion has been closed. Please do not modify it.

Dear Sir, I was diagnosed for Cerebral Venous Thrombosis, bilateral papilloedema, left VI nerve palsy, Neck Supple, Plantar↓. I have been under conventional medication for the past 2 years and there are no signs of reducing my drug dosage. I started having side effects and when I spoke to my Neuro Physician about the side effects. I was told it is to be expected due to drug effects.

For a holistic approach for my medical condition, I started taking Acupunture for the past 3 weeks. I feel lot of relief.

But I need to know if there is any document on positive relief for CVT. I am unable to locate any document, article on effects of Acupunture treatment for CVT.

Can you please guide me on the topic.Marhabha (talk) 06:59, 4 February 2013 (UTC)[reply]

We cannot give any medical advice. Articles may be at acupuncture and Cerebral venous thrombosis. Graeme Bartlett (talk) 08:32, 4 February 2013 (UTC)[reply]

Graeme is right; we cannot give medical advice. Talk to your physician again and ask him the specific question you asked here. Typing the name of the medication in the Wikipedia search box may lead you to other relevant Wikipedia pages. --Guy Macon (talk) 10:02, 4 February 2013 (UTC)[reply]

freezing insect eggs?

Various sources suggest putting insect prone food (oatmeal, rice, etc.) in the freezer to kill the eggs; but I'm dubious. Does that really kill the eggs, or just keep them from hatching while it's actually in the freezer? Because if it does kill the eggs, why don't they treat the food at the plant before selling it? Gzuckier (talk) 07:34, 4 February 2013 (UTC)[reply]

The ability to reliably survive freezing is a rare trait in insects. I think you can be confident the eggs really do die. No clue why they're not so treated before hand if its a real concern. My guesses would be that either some of in the insect contamination is post-shipping, or they are being cheap. Someguy1221 (talk) 07:42, 4 February 2013 (UTC)[reply]

This is pure anecdote but you can take what you want from it. I found a superb local baker but unfortunately his flour has flour moth and after a couple of weeks I had some flying out of my bread box. I bought in batches of a dozen loaves, putting most in the deep freezer until needed. This action had no effect on the viability of the eggs, they survived the freezer for up to 3 weeks. I now reheat the loaves in a hot oven for 5 minutes. No moths. Richard Avery (talk) 08:04, 4 February 2013 (UTC)[reply]

woah dude, I'd be looking for a different baker myself ---- _nonsense ferret 13:14, 4 February 2013 (UTC) [reply]

For good bread I go the extra mile! Richard Avery (talk) 14:07, 4 February 2013 (UTC)[reply]

We have our very own baker for that. He may be a bit off your beaten track, Richard. You may have to go the extra 5,000 miles. -- Jack of Oz ^[Talk] 08:07, 5 February 2013 (UTC) [reply]

Different insects have different amount of resistance to freezing[10][11] and even different basic strategies.[12] One surprising aspect of this is that many insects are better at surviving freezing if they have experienced winter weather in the previousmonth[13] -- insects generally do not maintain their cold protective systems when their environment remains relatively warm. --Guy Macon (talk) 10:28, 4 February 2013 (UTC)[reply]

It is doubtful that the moths came from eggs in the baker's flour; they wouldn't survive the bread baking process (note your 5-minute re-heat). I had this problem until I lined my pantry with "Spanish cedar" (which is neither Spanish nor cedar). ~:74.60.29.141 (talk) 18:17, 4 February 2013 (UTC)[reply]

I agree, there is no way the moths came from the baked loaves. They probably simply live in your house and are attracted to the crumbs left over in the bread box. So your experiment of freezing them did not determine anything. If reheating them does anything, you are simply killing eggs that are laid, in your house, on the outside of the loaf. As a practical suggestion buy a pheromone sticky trap made for pantry moths. Ariel. (talk) 18:42, 4 February 2013 (UTC)[reply]

It sounds like freezer temperatures should kill any stage of Ephestia kuehniella [14] [15] (99% of eggs in 5 hours). But the other one... would you believe somebody wrote a book about it? But no freeview. Still, [16] says that eggs are the hardiest stage and 99% of them die in 6 hours. Then again, I don't know the species for sure. Wnt (talk) 19:14, 4 February 2013 (UTC)[reply]

As it happens I had a detailed conversation with the baker and they are aware of the problem and are embarking on a new pheromone based capture strategy. They flour the baked loaves with unbaked flour and this is the source of the eggs, so there we are - I came to offer some personal advice not seek comments about my eating habits. I'm not complaining, they bake the best bread I've ever eaten. Richard Avery (talk) 19:22, 4 February 2013 (UTC)[reply]

Thanks for the encouraging advice; particularly since I could potentially stash stuff outside in winter for a bit.... but anyway, in regard to the tangent re contamination in said baker's place; the reason I asked is because I'm getting so many products contaminated. I did at first think perhaps they were getting contaminated by a domestic infestation, although why certain products would or wouldn't get infested is a question, so I started stashing each item I bought in a tupperware or similar container as soon as it got home, but that didn't improve things, so I assume they're getting imported in the food. Not just the usual stuff you'd expect like flour or rice, but processed stuff like spaghetti, hot cocoa mix, etc. Of course, FDA regulations are always grosser than the layperson expects. Gzuckier (talk) 19:41, 4 February 2013 (UTC)[reply]

Why would they flour the baked loaves with unbaked flour? It's normal to use some flour as a release agent, but that flour gets baked. Why add unbaked flour after? Ariel. (talk) 19:54, 4 February 2013 (UTC)[reply]

Are you saying that bread, flour, rice, spaghetti and hot cocoa mix all have the same insects even when stored in Tupperware? So what is common to all? Same store? Same warehouse feeding multiple stores? Could it be something weird like always leaving the food on the same rug or in the same auto trunk for a while or maybe all your Tupperware has loose lids? (Not that I believe that any of those could be the common factor, just asking what all the foods have in common) --Guy Macon (talk) 20:26, 4 February 2013 (UTC)[reply]

Looks to me like the same guys; they never get past the larvae stage, those little beige guys with dark heads. I've wondered the same thing. For stuff like spaghetti in the usual box, I can see that the parents could get in anywhere along the line, but the cocoa baffled me. (Individual single serving foil packages in the box). Only some foil packs had bugs, and you could tell a priori because they had little holes in the foil; i'm convinced those were the larvae chewing from inside out, rather than outside in because 1) it was only some of the foil packs, not all 2) there was no evidence of insects outside the foil, despite the holes 3) logically, how would the eggs hatch and grow into larvae that could chew through the foil outside the pack without anything for them to eat? And some brands had the problem, some didn't, which may be just random sample variation. So i'm somewhat baffled. If I ever find holes chewed in tin cans, I'm going to panic. Gzuckier (talk) 16:49, 5 February 2013 (UTC)[reply]

Sounds like weevils, which are known to infest pantries and then be found in all your starch boxes. When I was little and we moved from the US South to the North we brought them with us and they took keeping everything in tins or the freezer finally to get rid of. μηδείς (talk) 01:10, 6 February 2013 (UTC)[reply]

Evolutionary purpose of non-reproductive sex

From the perspective of evolution, the purpose of sexual intercourse is reproduction, and the purpose of reproduction is species continuation. But some species such as bonobos, dolphins and humans have non-reproductive sex. From the perspective of evolutionary biology, what is the purpose of non-reproductive sex? Even from an evolutionary perspective, non-reproductive sex may be harmful to a species as it will create continuous sexual competition and resulting injuries and death. So does it provide any evolutionary benefit? --PlanetEditor (talk) 17:51, 4 February 2013 (UTC)[reply]

We have an article Animal sexual behaviour which despite its flaws, goes in to this in a variety of ways. Our article Bonobo#Sexual social behavior also discusses it as specific to bonobos (notably it appears to function somewhat the opposite of what you're suggesting). We have a large number of articles like Human sexuality covering sex among humans and related topics (Concealed ovulation for example may be of interest) although if you're old enough you may have ample knowledge that sex can serve many purposes among humans many of which will have a variety of possible evolutionary benefits. Nil Einne (talk) 18:56, 4 February 2013 (UTC)[reply]

Pair bonding - "sex for pleasure" keeps the male close enough to the female to contribute (directly or indirecty) more than just his gametes to raising offspring. Roger (talk) 19:06, 4 February 2013 (UTC)[reply]

It's a fallacy, selectionism, to assume that every aspect of biological organisms has to be seen as serving some evolutionary purpose. μηδείς (talk) 20:30, 4 February 2013 (UTC)[reply]
Gould was a known anti-sociobiology writer. You need to find a neutral source. It is absolutely possible to explain each and every physiological and behavioral feature of a species, including humans, in evolutionary terms. --PlanetEditor (talk) 05:13, 5 February 2013 (UTC)[reply]

Absolutely. And if we accept the suggestion that there's competitive advantage in making reproductive sex pleasurable, the pleasure in non-reproductive sex appears to come as a trivial side-effect. AlexTiefling (talk) 22:50, 4 February 2013 (UTC)[reply]

Take a look at Why Is Sex Fun?, which gives many evolutionary arguments for why it is so. Shadowjams (talk) 01:05, 5 February 2013 (UTC)[reply]

Non-reproductice sex exists because sex conveys an evolutionary advantage, and prevention of non-reproductive sex doesn’t. - Nunh-huh 02:37, 5 February 2013 (UTC)[reply]

That's a non-answer, it just restates the question in different terms. What the OP is asking about is what the evolutionary advantage is. --Jayron32 04:56, 5 February 2013 (UTC)[reply]

Actually, Nunh-huh's answer is correct if you add the premise that non-reproductive "side effects" arise from successful reproductive ones. If females being attracted to males is a well successful strategy, but it results in certain males also being attracted to other males, it will exist because the first is a very successful strategy and the second doesn't matter. Evolution doesn't care about the homosexuality of the male in that circumstance so long as his mother and sisters are successful. μηδείς (talk) 05:19, 5 February 2013 (UTC)[reply]

You could add any number of sentences to Nunh-huh's answer to make it correct. He didn't add any such sentences. What he wrote, however, is neither correct nor incorrect, merely a redundant restatement of what evolution is. --Jayron32 05:30, 5 February 2013 (UTC)[reply]

OP, you say that some species have non-reproductive sex, and you mention bonobos, dolphins and humans as examples. I prefer to believe that pretty much all species engage in this behaviour. Can you show me a single species where conception occurs every time they have sex? Or that the participants could care less either way? (other than humans; we seem to be the only species for whom this is an issue) They enjoy getting their rocks off as much as we humans do. -- Jack of Oz ^[Talk] 05:23, 5 February 2013 (UTC)[reply]

Evolution isn't trying to weed out those traits that do not contribute to survival and reproduction. Evolution describes how small advantages in survival and reproduction tend to be perpetuated in succeeding generations. Non-contributory traits, as long as they are not too disadvantageous or are merely neutral vis-a-vis survival and reproduction, tend to be perpetuated as well. Bus stop (talk) 05:54, 5 February 2013 (UTC)[reply]

One more question. Are only the animals with menstrual cycle exhibit non-reproductive sex? --PlanetEditor (talk) 06:48, 5 February 2013 (UTC)[reply]

No. Many types of birds pair up for life, or at least long periods of time, and enjoy sex for bonding purposes. Birds do not menstruate. Wickwack 121.221.92.200 (talk) 06:57, 5 February 2013 (UTC)[reply]

I remember reading a book titled "Hung Like and Argentine Duck" which provided a rather interesting overview to the evolution of sexual intimacy (as the author termed it). As I recall, the author provided several examples where non-procreative sexual behaviors carried distinct benefits for the individual. For example, 'homosexual' behaviors in male garter snakes led to them being warmer than their counterparts and therefore more attractive to females. In species with social structures increased cooperation also increased the likelihood of one individual in that group being able to pass on their genes, or for a close relative to do so. So it may be possible that some of these these behaviors may have actually been positively selected for. 130.102.158.16 (talk) 02:49, 6 February 2013 (UTC)[reply]

Coffee

How many typical styrofoam cups of caffeinated coffee, filled approximately 3/4 of the way, does an average person needs to drink consecutively in order to be killed by caffeine overdose? 140.254.121.34 (talk) 19:28, 4 February 2013 (UTC)[reply]

This is perhaps a trick question. Ignoring the size of a "cup" for now, the article caffeine says 80 to 100 cups of coffee have a 50% chance of doing the trick. But if a cup is indeed a cup, then this is 40 pints, 20 quarts, five gallons of water, and water intoxication would probably set in sooner than that. Therefore, you should not be able to die of caffeine overdose because something else would kill you first. :) But ... differences in cup size, and the length of time required to clear water versus caffeine from the system, might undermine that. Funny, I just can't interest myself in doing this math, though I feel like for some reason differences in cup size should normally be more interesting. :)Wnt (talk) 19:41, 4 February 2013 (UTC)[reply]

It takes quite a large amount of caffeine to be dangerous. Caffeine can start causing problems once you consume more than 1 gram of the substance and be lethal at 10 grams, so doctors like [Cleveland Clinic cardiac surgeon] Gillinov recommend that people don't consume more than 400 to 500 milligrams a day. For comparison, he said an average cup of tea has about 40 miligrams while a tall cup of Starbucks coffee (12 ounces) has about 260 milligrams of caffeine, though other brands average about 100 milligrams for a regular sized cup. —Castillo, Michelle (October 24, 2012). "Can you overdose on caffeinated drinks?". CBS News. CBS Interactive, Inc. ~:74.60.29.141 (talk) 19:53, 4 February 2013 (UTC)[reply]

Great! Now you have me craving coffee! Thanks. μηδείς (talk) 20:25, 4 February 2013 (UTC)[reply]

Twin fingerprints

Are identical twins born with identical fingerprints, and then the prints diverge later as they grow, or are they born with different fingerprints? RNealK (talk) 22:54, 4 February 2013 (UTC)[reply]

Different fingerprints. Uncle Cecil says so. Identical twins are only identical genetically. They will develop in non-identical environments, and as a result will have subtle differences, including fingerprints. This NYT column briefly explains the effect of subtle environmental difference, and itself links to more in depth documents. --Jayron32 23:17, 4 February 2013 (UTC)[reply]

Thanks. RNealK (talk) 23:22, 4 February 2013 (UTC)[reply]

February 5

Yellow rain

In December 2012 Sri Lankan towns such as Mineragala and Southern provinces experienced Red rain and towns of Polonnaruwa and Kantale experienced Yellow rain. But the article about yellow rain totally differs from this rain. So natural yellow rain should be also included here. Sri Lanka based researches reveal that this colouration of monsoon rains was due to remains of meteorites. So what is the difference between natural and artificial ones? Source:

[17]
[18]
Rupavahini broadcasting (government's official broadcasting channel)

--G.Kiruthikan (talk) 07:06, 5 February 2013 (UTC)[reply]

I fixed the dead links above. Sean.hoyland - talk 07:38, 5 February 2013 (UTC)[reply]

Both the red rain and the natural form of yellow rain are actually varieties of blood rain, which is caused by large quantities of dust and pollen in the air (the meteor hypothesis, BTW, has been disproved). "Artificial" yellow rain, however (I put it in quotes because its very existence is unproven) is a hypothetical Soviet chemical weapon allegedly used against South Vietnam by the Vietcong in 1975, which may be composed of various mycotoxins, mustard gas, etc. FWiW 24.23.196.85 (talk) 08:53, 5 February 2013 (UTC)[reply]

Law of excluded middle, null hypothesis, and disproof of god

Hi, folks, God here. IP 24 has it right, I don't approve of people debating my existence at a ref desk.

The following discussion has been closed. Please do not modify it.

Ok so let's say that the statement "god doesn't exist" is the null hypothesis and "god exists" is the alternative hypothesis. So the null hypothesis can not be proven and is the default position, that directly implies that the claim "god doesn't exist" can not be proven. Let's define god as the being that is described in The Book of Genesis. Since this being has been described as creating humans, that is a demonstrable claim that can be falsified. Evolution has falsified creationism, and therefore the god described in The Book of Genesis has been disproven. According to the Law of excluded middle, two contradictory propositions (i.e. where one proposition is the negation of the other) one must be true. Since the alternative hypothesis has been disproven, it stands to reason that the null hypothesis must be true according to the Law of excluded middle. So my question is, can something be true, without it being proven (using this logic)? ScienceApe (talk) 02:00, 5 February 2013 (UTC)[reply]

This is the reference desk. Can you rephrase that as a specific request for research help, rather than a long invitation to debate? μηδείς (talk) 02:13, 5 February 2013 (UTC)[reply]

A statement can be assumed true, and thus require no proof. This is the essence of the method by which most religious persons justify their convictions. 72.128.82.131 (talk) 02:38, 5 February 2013 (UTC)[reply]

Your argument utilizes the strawman argument and is not a proof; and "using this logic" [sic] one can prove anything. ~:74.60.29.141 (talk) 02:44, 5 February 2013 (UTC):~[reply]

Or disprove anything. No believer has ever come up with any evidence that would convince a scientist there is a god, and no scientist has ever been able to cause a believer to doubt there is a god. Then there are scientists who teach evolution but privately are strong believers in the God who created the universe ab initio. Work that out. -- Jack of Oz ^[Talk] 02:53, 5 February 2013 (UTC)[reply]

Not to mention that God and evolution are not mutually-exclusive. [I didn't mention that] ~:74.60.29.141 (talk) 03:48, 5 February 2013 (UTC):~[reply]

The flaw here is in this line: "Since this being has been described as creating humans, that is a demonstrable claim that can be falsified."...Sadly, that is not the case. God is described as being "omniscient" and "omnipotent" - and that's a major problem for any disproof of his existence. If this is true, then he can do absolutely anything. For example: He could create humans (per Genesis), then completely falsify all of the evidence (planting fake fossils, adding appropriate junk DNA, etc) to make it look to scientists like we evolved from pond-slime...or he could warp the minds of scientists who investigate evolution to make them believe it to be true and to ignore contradictory evidence. Heck, it might be that not one single person in the world believes in evolution but God decided to warp your mind to make you think that it's widely accepted as true. Maybe he allowed evolution to do the work and then faked the creation of the book of Genesis. An omnipotent being has literally no limits...that's why the non-existence of God is unfalsifiable - even by complicated arguments like yours. Of course my claim that there are omnipotent, green, piano-playing aardvarks living on the dark side of the moon is also unfalsifiable - and so are an infinite number of other possibilities. The "God hypothesis" therefore has a statistically infinitesimal (but not zero) probability of being true...so rational beings may ignore that possibility. SteveBaker (talk) 16:17, 5 February 2013 (UTC)[reply]

Your final sentence does not logically follow. The premise that there are is an infinite number of possible omnipotent beings does not lead to the conclusion that the probability for each of those possibilities is infinitesimally small, because that requires the unstated (and unproven) assumption that each of those possibilities is equally probable. - Lindert (talk) 16:36, 5 February 2013 (UTC)[reply]

Yeah - that's true to a degree - but since these are unfalsifiable hypotheses and none of them (including the "God hypothesis") has any solid evidence to prove them, our best guess has to be that they are equally probable. SteveBaker (talk) 20:41, 5 February 2013 (UTC)[reply]

The trick here is that you are defining "god" very narrowly here, as being not merely the god of Genesis but a particular interpretation of that god which is one whose work must leave evidence demonstrably contradictory to evolution. So your proof of "god not existing" is equally narrow. You have not, for example, disproved that there could be a God who created the world as in Genesis, but who subsequently covered up his prior work by some miraculous means to leave only evidence of the natural history implied by our current laws of physics; or who did the creation in a parallel universe and copied and refined it in this one; or who did the work in some sort of Platonic realm of archetypes; etc. Wnt (talk) 05:12, 5 February 2013 (UTC)[reply]

I am not personally very interested in not the god-vs-no-god debate - at least, not at face value. I feel that this debate has been rehashed by many intelligent people, and many many more unintelligent people, for many centuries, and in many languages. What I am interested in is the Kolmogorov complexity of their debate, and more importantly, the marginal contribution to that complexity of any new individual's argument. I fear that we are reaching a plateau, where the complexity no longer increases, because the exact same arguments for each side are made, over and over and over again, by people who have chosen not to invest the time to read the earlier parts of the "thread." Now, it's a heck of a lot of effort to expect every Tom, Dick, and Harry to start off with Plato and Thomas Aquinas and Sartre; but by golly, if somebody's interested in the subject, then they really ought to invest the time to read all the prior arguments so that we can make forward progress in the discussion, instead of repeating the same string-literal arguments, without adding to the complexity. (And yes, I posit that in five centuries of English, and five decades of digital texts, somebody has written almost exactly the same string of text as your brilliant idea to prove, or disprove, anything). If only there were a free repository of great classic literature, and short encyclopedic summaries to help guide the interested reader through the denser parts of the prose... I bet each person could expend a little effort to ramp up on "prior art," and there would be much less repetition of the elementary tenets of formal logic, theology, and the general theory of human knowledge. And more to the point, we could then process this digital corpus to estimate the Kolmogorov complexity of the god-vs-no-god debate, giving us an upper-bound of the importance of it, as measured in bits-of-entropy. We could then compare that to the bits of entropy in other observed phenomena. Nimur (talk) 05:28, 5 February 2013 (UTC)[reply]

This is not a place for religious debates. Why don't we just hat the whole thing? 24.23.196.85 (talk) 05:39, 5 February 2013 (UTC)[reply]

Malala, the girl who survived the Taliban's assassination attempt, today called her survival a gift from God. And there's not a soul on earth who can prove her wrong. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:47, 5 February 2013 (UTC)[reply]

Being nearly assassinated and surviving? I think I'll pass on gifts from God then thank you very much. Dmcq (talk) 10:30, 5 February 2013 (UTC)[reply]

The assassination attempt was a "gift" from evil people. If you would prefer not to survive an assassination attempt, that's up to you. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:46, 5 February 2013 (UTC)[reply]

That's the old argument from The God Delusion - why did Our Lady of Fatima not guide the bullet another 20cm that way? Or, more generally, why is there evil in the world? If you assign all evil in the world to "evil people", and all good to god, what stops me from doing the same with communism, or Thor, or the Beach Boys? --Stephan Schulz (talk) 21:47, 5 February 2013 (UTC)[reply]

Right, the assassination attempt was by humans because it was evil, whereas the recovery was by God because it was good. Teams of dedicated doctors, sophisticated medical devices, and generous donors obviously had nothing to do with it. Apparently, a 14 year old girl with zero scientific training and minimal scientific knowledge is now the world's sole scientific authority. --140.180.247.198 (talk) 15:51, 5 February 2013 (UTC)[reply]

more for us165.212.189.187 (talk) 13:58, 5 February 2013 (UTC)[reply]

I would guess the Taleban think they follow God's teaching and British surgeons are in general misguided infidels even, dare I mention it?, atheists and evil has triumphed for the moment in this case by saving her life. Dmcq (talk) 17:10, 5 February 2013 (UTC)[reply]

As (it seems to me) usual in these debates, it all hinges on each individual's definition of "God"; and (it seems to me) any such concrete definition can be disproved, the more concrete and specific the easier to disprove. In this case, God defined as the God of the first portion of Genesis. This doesn't lead to any ending, however, if one's definition of God includes transcendence over concrete definition by the human intellect. See Neti neti and Apophatic theology. Gzuckier (talk) 18:09, 5 February 2013 (UTC)[reply]

feeling "surreal" or like the world is a fabrication or a simulation

Is this a known symptom of psychosis? This is not a medical question, I just wonder if there are lots of people in society with undiagnosed schizotypal disorders, thanks. 71.207.151.227 (talk) 11:44, 5 February 2013 (UTC)[reply]

This is not about the philosophical belief, more like the emotional feeling that people have, i.e. it is a very visceral feeling. 71.207.151.227 (talk) 11:44, 5 February 2013 (UTC)[reply]

see Derealization, the reference desk cannot provide a medical opinion or speculation ---- _nonsense ferret 13:00, 5 February 2013 (UTC)[reply]

And yes it stands to reason that there are lots of people in society with undiagnosed mental illness. The NIMH found that half of all cases of mental illness begin by age 14, and that " there are long delays — sometimes decades — between first onset of symptoms and when people seek and receive treatment". --TammyMoet (talk) 13:04, 5 February 2013 (UTC)[reply]

Why do questions like this make me feel like wikipedia is a potentially endlessly recursive computer platform? μηδείς (talk) 20:44, 5 February 2013 (UTC)[reply]

Ask somebody to kick you in the shins, and then get back to us about whether it seemed "real" or not. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:28, 5 February 2013 (UTC)[reply]

Whenever I suggest that people accuse me of being cruel! μηδείς (talk) 23:32, 5 February 2013 (UTC)[reply]

I might call it the Three Stooges Experiment. If it's real, it hurts. If not, it doesn't. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:40, 6 February 2013 (UTC)[reply]

Zycosoil

Please help me by telling me what is the generic name for Zycosoil — Preceding unsigned comment added by 188.245.230.38 (talk) 12:35, 5 February 2013 (UTC)[reply]

A Google search shows it is a waterproofing agent. --PlanetEditor (talk) 12:57, 5 February 2013 (UTC)[reply]

I need to know what is the generic name for Zycosoil that is manufactured in India.

188.245.230.38 (talk) 13:13, 5 February 2013 (UTC)[reply]

It seems to be a fairly unusual product and I'm not sure that there is an agreed generic term for it. It is used to protect soil from water erosion so it could be called a 'soil protective' or an 'erosion preventer', You might find this link useful as it has a video demonstrating the action of Zycosoil. This may be a Language Desk question. Richard Avery (talk) 14:32, 5 February 2013 (UTC)[reply]

Organosilicon compound — See also: [19] ~:74.60.29.141 (talk) 17:05, 5 February 2013 (UTC):~[reply]

Chelating?

Has chelating have any other practicle purposes other than medical? Would the removal of rust be called this . . . or has it another name? — Preceding unsigned comment added by Cousin Bruce (talk • contribs) 13:34, 5 February 2013 (UTC)[reply]

Our article suggests it has other uses than medical Zzubnik (talk) 13:46, 5 February 2013 (UTC)[reply]

One application they missed is hydrometallurgy: for example, chelating agents can be used to extract boron from seawater, or plutonium from a nitric acid solution of spent nuclear fuel (among many other things)... 24.23.196.85 (talk) 05:22, 6 February 2013 (UTC)[reply]

Vacuum of space

does the vacuum of space exert a negative energy on objects in an outward and perpendicular direction to the surface of the objects?165.212.189.187 (talk) 14:06, 5 February 2013 (UTC)[reply]

That's sort of a backwards way to look at it. Any object in space, let's say a human who forget his space suit, has some internal pressure (blood pressure is one form of this). On Earth this is countered by atmospheric pressure. Without this, in space, there is an unbalanced outward pressure which causes the person to swell up. StuRat (talk) 14:23, 5 February 2013 (UTC)[reply]

Wikipedia says negative energy is "A plot device in fiction" Zzubnik (talk) 14:24, 5 February 2013 (UTC)[reply]

OK a positive energy from the negative mass density of space. so the vacuum of space is not exerting outward pressure on the earth? that only applies to objects with inertial outward pressure, (which the earth does not have)?165.212.189.187 (talk) 14:31, 5 February 2013 (UTC)[reply]

"Things" have internal pressure. Vacuum of space does not exert a force at this scale. Zzubnik (talk) 14:39, 5 February 2013 (UTC)[reply]

So the gravity of earth prevents its internal pressure from exploding like the human without the suit?165.212.189.187 (talk) 15:26, 5 February 2013 (UTC)[reply]

Yes, gravity holds it all together. There's also the effect of the solar wind, which tends to blow off lighter elements at the top of the atmosphere, explaining why there is so little free hydrogen and helium in the air, despite those being the most common elements in the universe. BTW, a human in space doesn't explode, he just swells up. StuRat (talk) 15:48, 5 February 2013 (UTC)[reply]

Also, the use of the word "Energy" in the question is completely incorrect. Force would've been a much better choice. Energy doesn't have a direction in space and cannot point outward or be perpendicular. Neither does pressure. Dauto (talk) 16:14, 5 February 2013 (UTC)[reply]

Thanks for clarifying. Why doesnt gravity hold the human together the same way?165.212.189.187 (talk) 16:52, 5 February 2013 (UTC)[reply]

Gravity doesn't by itself help with holding humans together; a man on the moon experiences gravity, but because the lunar atmosphere is practically nonexistent, he'd swell up as if he were in a vacuum. Launch him back into space inside a spaceship, and he'll be safe because of the air inside the spaceship, even though he's experiencing no gravity. It's simply that Earth's gravity holds the atmosphere that prevents us from swelling up. Humans have their own gravity, simply because all matter does, but we're far far too tiny for that gravity to have any practical effect. Nyttend (talk) 17:23, 5 February 2013 (UTC)[reply]

But that doesn't explain why the human will swell and the earth doesn't. Also if the swell is an action in the outward direction then what is responsible for stopping the swell. ...object in motion will stay in motion, no?165.212.189.187 (talk) 19:00, 5 February 2013 (UTC)[reply]

The same thing which keeps a balloon from exploding when you inflate it. The membranes are strong enough to withhold a certain amount of pressure, but too much pressure would, indeed, cause both to explode. StuRat (talk) 20:00, 5 February 2013 (UTC)[reply]

Gravitational forces are proportional to the mass of the object producing it. A person's gravity is simply to week to hold an atmosphere. Dauto (talk) 01:56, 6 February 2013 (UTC)[reply]

Intermezzo (zolpidem tartrate)

In the past, medications avoided English words as their names, presumably so the pharmaceutical company could protect the trademark ~~copyright~~ more easily. So, why does this med have an English name ? Has something changed ? StuRat (talk) 15:09, 5 February 2013 (UTC)[reply]

Hmmm, is that more English than Allegra? Wnt (talk) 15:37, 5 February 2013 (UTC)[reply]

I don't speak Italian, yet know what "intermezzo" means. So, to me, that means it has now become an English word, like "pizza". StuRat (talk) 15:51, 5 February 2013 (UTC)[reply]

If they thought that avoiding English words as drug names helps to protect trademarks (note: not the same thing as copyrights - there are no one-word copyrighted works) then they don't understand trademark law. Apple (the computer), Genesis (the band) and Mercury (the car) have no trouble protecting their trademarks. Mostly the name choices reflect style. You can look at the drug names "Dr. Bateman's Pectoral Drops" and "Lipitor" and figure out roughly when they were introduced. --Guy Macon (talk) 18:54, 5 February 2013 (UTC)[reply]

Who are "they"? The medications? --Trovatore (talk) 03:13, 6 February 2013 (UTC)[reply]

microbiology

Principles of pregenancy test — Preceding unsigned comment added by 93.186.23.89 (talk) 15:21, 5 February 2013 (UTC)[reply]

Information about different types of pregnancy tests and the principles by which they operate can be found in the Wikipedia article pregnancy test. TenOfAllTrades(talk) 15:29, 5 February 2013 (UTC)[reply]

Live double-headed eagles

Has a live double-headed eagle (or the body of a dead one) ever been recorded, as far as Reference Deskers know? I know that conjoined twins have been found in multiple non-human mammalian species, and I'm pretty sure that I've read about them in other chordates (amphibians, perhaps?), so I don't imagine that it would be completely impossible for the same phenomenon to appear in birds. Google gave exactly eight results, and they were either "I'll buy you a live double-headed eagle for your birthday!" or lists in which "live" happened to be right before "double" etc. Nyttend (talk) 17:18, 5 February 2013 (UTC)[reply]

Gah. I'm sure I saw an exhibit of a double-headed eagle at the Odditorium in Blackpool when I was a child. However, I don't think you can search the "Believe It Or Not" website to try and find it. Maybe someone more computer savvy than I can find it. Anyway, thanks for getting me to a site I'd been meaning to find for some time. I may be some time! --TammyMoet (talk) 18:26, 5 February 2013 (UTC)[reply]

A huge number of those kinds of things are faked by clever taxidermists. I don't think "having seen one" really tells us much either way here. SteveBaker (talk) 20:32, 5 February 2013 (UTC)[reply]

There are a number of images of two headed birds on the internet which may or may not be genuine. This one looks kosher though. Richerman (talk) 20:45, 5 February 2013 (UTC)[reply]

Double-headed eagle is a very well known symbol in European heraldry. It's been on the coats of arms of numerous countries, and is currently on the national flags of Albania, Serbia and Montenegro. Countries tend not to have mythical animals in their symbology, so I'm assuming it had some real basis. -- Jack of Oz ^[Talk] 22:00, 5 February 2013 (UTC)[reply]

Unicorns, dragons and phoenixes have all been used in European heraldry. I take it the OP is referencing double-headed snakes? CS Miller (talk) 22:32, 5 February 2013 (UTC)[reply]

Huh? I'm looking for members of the family Accipitridae (I suppose I'd accept non-eagles from that family) with two heads, in part because I'd already looked at the article Jack links, and I observed that it doesn't discuss the existence or nonexistence of individual members of this family that appeared to have two heads. Snakes hadn't even come to mind; I can't remember ever hearing of a two-headed snake. Nyttend (talk) 23:00, 5 February 2013 (UTC)[reply]

See polycephaly and here. I remember reading or hearing that two-headed carnivores usually attack each other, which would explain the lack of such birds. μηδείς (talk) 23:40, 5 February 2013 (UTC)[reply]

Two headed carnivores usually attack each other? - you can't be serious! Richerman (talk) 00:40, 6 February 2013 (UTC)[reply]

I certainly can be serious that I remember hearing, I think it was about turtles, that they would bite each other. If I had a reference (probably one of those 10 most craziest critters shows) I'd give it but it's not the sort of thing I keep files on, sorry. Lol. μηδείς (talk) 01:05, 6 February 2013 (UTC)[reply]

Black sky at night

Given that there are "billions and billions" of stars and that light (obviously) travels at the speed of light, why do we see so much "black" in the night sky rather than filled with starlight? Thank you. Rdhartwell (talk) 21:04, 5 February 2013 (UTC)[reply]

Black#Why the night sky and space are black - Olbers′ Paradox --Guy Macon (talk) 21:12, 5 February 2013 (UTC)[reply]

More to the point, Olbers' paradox. --Jayron32 21:25, 5 February 2013 (UTC)[reply]

The universe is finite and expanding, which explains why it is not infinitely bright in all directions, but it does glow in all directions, see cosmic background radiation. μηδείς (talk) 23:42, 5 February 2013 (UTC)[reply]

The universe is not in fact known to be finite. See shape of the universe. (The observable universe is finite, but that's different.) --Trovatore (talk) 03:04, 6 February 2013 (UTC)[reply]

Economic growth , what curve?

We are constantly told that economic growth is brilliant for us (I think it's to do with GDP?)

However what kind of growth are they implying? Linear? Exponential? Does it head towards a limiting value?

(edit) Also if it IS Exponential won't that be completely unsustainable and almost a joke that economic growth is even talked about as a fact?

Ap-uk (talk) 21:35, 5 February 2013 (UTC)AP[reply]

If you get "X" number of economists to answer this question, you're likely to get "X+1" different answers. If economists knew what drove the world economy towards a positive outcome with any certainty, we'd have been there yesterday. --Jayron32 21:37, 5 February 2013 (UTC)[reply]

(from op) If it is exponential and say 3% growth I see a problem with sustaining it now as the Wikipedia article sites 1830 as a start date [[20]] . At 3% we would get doubling every 23 years and it's the old wheat on a chessboard problem [[21]] as we now are getting onto the second row where the next 23years growth must equal the sum of all that has gone before in order to grow.

Except it's not a problem, because 1) nobody's saying exponential growth can continue forever, and 2) due to inflation, you have to distinguish between growth in real and nominal terms. If the inflation rate is 2%, that means all money in the country will be worth 2% less next year. Even if the economy produces exactly the same amount of goods and services next year, its nominal growth rate will still be 2%, even though real growth is 0%. --140.180.247.198 (talk) 23:52, 5 February 2013 (UTC)[reply]

Burnt stew

I have a 32 quart stainless steel stock pot in which I made some stew from chicken, potatoes, onions, green beans, baby carrots, corn, dried beans, etc. I filled it almost to the top, and boiled it vigorously over an open flame. I left it uncovered, since this prevents boiling over and I don't mind the heat and humidity in winter. Everything went well the first day, and the pot was still half full by night (maybe 1/4 boiled off and 1/4th was eaten). So, I covered it and left it to cool. Early the next morning, it was still warm, and I turned the flame back on. Then I detected a burning smell. So, since the pot was still half full, something must have adhered to the bottom and started to burn. Is there any way to prevent this, other than constant stirring ? Would it have helped if I oiled the pot before using it ? Should I have left the dried beans out ? StuRat (talk) 23:17, 5 February 2013 (UTC)[reply]

How does leaving it uncovered keep it from boiling over? ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:22, 5 February 2013 (UTC)[reply]

Covering a pot retains the heat that would otherwise be lost as the water vapor leaves the pot, allowing heat to build to a point where it boils over, right after knocking the lid askew. Leaving it uncovered prevents this (of course, an uncovered pot still can boil over, but this requires a significantly higher flame). StuRat (talk) 23:32, 5 February 2013 (UTC)[reply]

Put a saucepan nearly full of water on a burner of your stove, turn on the heat, watch it boil, and tell me that it doesn't boil over. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:30, 6 February 2013 (UTC)[reply]

My guess is that after you removed the heat and left it overnight, the ingredients compacted on the bottom and more and more as time went on, with the moisture at the layer touching the bottom of the pot reducing. In the morning when you turned the flame back on you were essentially heating rather dry ingredients which promptly burned. If you had given the pot one thorough stir (as opposed to constant stirring) before turning the flame I think you might have avoided the problem.--Fuhghettaboutit (talk) 23:42, 5 February 2013 (UTC)[reply]

Yes, one stir on reheating was all that was necessary. μηδείς (talk) 23:44, 5 February 2013 (UTC)[reply]

OK, I'll try that tomorrow. StuRat (talk) 00:15, 6 February 2013 (UTC)[reply]

February 6

Law of excluded middle, null hypothesis redux

I have to ask this question again because it wasn't answered and was actually side tracked by a discussion I didn't intend. Long story short, can something be true, without it being proven? ScienceApe (talk) 01:34, 6 February 2013 (UTC)[reply]

How would you prove that it hurt if I kicked you? Can you prove that existence exists without referring to anything which exists? There are axioms, and perceptions, neither of which can be proven true, but both of which are assumed veridical. The law of the excluded middle is also axiomatic--it is the basis for any proof, but cannot itself be proven without assuming its own truth. μηδείς (talk) 01:43, 6 February 2013 (UTC)[reply]

(ec) :If you believe in philosophical realism, you pretty much have to believe that the answer is yes. --Trovatore (talk) 01:44, 6 February 2013 (UTC)[reply]

You might also look at foundationalism and coherentism, both of which are true. Whereas skepticism is a self-refuting idea. μηδείς (talk) 01:48, 6 February 2013 (UTC)[reply]

Additional concepts to consider: [David] Hume's Law (a.k.a.: Is–ought problem derived from: Fact–value distinction. For an in-depth exploration of proof vs. truth as it relates to logical constructs and string theory, (etc.) - look into Gödel's In/Completeness theorem. ~Eric _the Read 74.60.29.141 (talk) 02:01, 6 February 2013 (UTC)[reply]

Should we treat Hume's theory as true? μηδείς (talk) 02:07, 6 February 2013 (UTC)[reply]

Maybe you ought to. ~E:74.60.29.141 (talk) 02:35, 6 February 2013 (UTC)[reply]

:) ---- _nonsense ferret 03:03, 6 February 2013 (UTC)[reply]

(edit conflict) I believe the bottom line of this discussion will depend on the definition of "truth", and the answer will be "yes/no". Can truth apply to itself? 74.60.29.141 (talk) 03:14, 6 February 2013 (UTC)[reply]

Define "prove". ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:28, 6 February 2013 (UTC)[reply]

The question is nonsense as are the "answers". If there's no such thing as truth, it isn't true there's no such thing as truth. If there's no such thing as proof, there's no proof there's no such thing as proof. This thread is ready to destroy itself. μηδείς (talk) 03:35, 6 February 2013 (UTC)[reply]

Such is the nature of Existence theorem: An existence theorem may be called pure if the proof given of it doesn't also indicate a construction of whatever kind of object the existence of which is asserted. (see also: Existential instantiation) ^>poof!< _{74.60.29.141 (talk) 03:48, 6 February 2013 (UTC)}[reply]

If you say "I'm thinking of ___", and if you're really thinking of that, it's true, but there's no way to prove it. Quite obviously the answer is yes. Nyttend (talk) 04:05, 6 February 2013 (UTC)[reply]

Unfortunately, that's not a very defensible example, because once the question is asked, you are thinking of "thinking of ____" - and you can immediately see the problem of recursive self-reference. -Thus the answer is both "yes" and "no" simultaneously. 74.60.29.141 (talk) 04:26, 6 February 2013 (UTC)[reply]

Very well to be pedantic about it; what about "I was thinking about __ two minutes ago", or what if you're in out in the woods by yourself (no cameras around) and see a leaf fall; you can't prove that you saw it fall, but it still fell. Nyttend (talk) 04:35, 6 February 2013 (UTC)[reply]

By the definition of "that which conforms to reality", it would indeed be true that the leaf fell (assuming that it actually did, which it didn't, since you just made-up that example). ;) ~:74.60.29.141 (talk) 05:06, 6 February 2013 (UTC):~[reply]

I said that the hypothetical you is claiming to have seen it fall; since I live in the woods by myself, I'm frequently able to see things happen, and it's easy to prove that they happened, but impossible to prove that I was watching when they happened. It's simply common sense, just like denying the paradoxical nature of the first two of Zeno's paradoxes that we list; we need not make an answer more complicated that the one given (according to the paradoxes article) by Diogenes the Cynic. Nyttend (talk) 05:26, 6 February 2013 (UTC)[reply]

(edit conflict) ~ If you define truth on a case-by-case basis such that there are an infinite number of definitions and an infinite number of proofs (e.g.: the leaf proved to you that it fell) - then the answer is "yes". ~:74.60.29.141 (talk) 05:31, 6 February 2013 (UTC):~[reply]

Touch one part of your body, feel it elsewhere

I was going through the Allochiria article and it made me wonder if this is similar to touching one part of your body and then feeling it elsewhere. I've seen this discussed elsewhere, like on this forum. Ok, so two questions: is there an actual word for that phenomenon (touch/scratch/whatever one area of the body and feel it elsewhere)? There is a reverse phenomenon that someone mentions at the bottom of that forum, which is, you feel an itch in one area, but scratching it doesn't relieve it because the itch is actually elsewhere.

Okay, second question is, is this the same thing used in the children's trick where Person A closes their eyes and holds their arm out. Person B slowly tickles their arm from the wrist up toward the elbow (the inside bendy part — cubital fossa). Person A is supposed to point out when Person B's reached the center of their elbow, but Person B won't have... sort of like an "optical illusion" for touch. Hopefully that makes sense. Reflectionsinglass (talk) 05:53, 6 February 2013 (UTC)[reply]