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January 27

Difference

Whats the diff tween nuclear scince and atomic scince..?--31.55.102.122 (talk) 01:17, 27 January 2014 (UTC)[reply]

With one, the future's so bright, you gotta wear shades (unless you're Feynman) Wnt (talk) 17:12, 27 January 2014 (UTC)[reply]

Technically, nuclear science deals with the nucleus of the atom, while atomic science, if there was such a term, would presumably deal with the entire atom. However, this is just chemistry. But, somebody might also use "atomic science" as a synonym for nuclear science, I suppose.StuRat (talk) 03:48, 27 January 2014 (UTC)[reply]

Yes, nuclear science has the connotation of dealing with radioactive reactions; fission or fusion. I am not sure atomic science is really used as a separate term, but there are such books as The Elements: Their Origin, Abundance, and Distribution: P. A. Cox that deal with the elements as such, whether inherently radioactive or not. μηδείς (talk) 04:03, 27 January 2014 (UTC)[reply]

See this graph and this graph to see the usage of the terms in English books that Google has scanned. "Atomic" as the term was more popular at first and then "Nuclear" became the new buzzword. Richard-of-Earth (talk) 10:46, 27 January 2014 (UTC)[reply]

Yes, that's right. They are synonyms, but atomic science is now dated. Spinning Spark 11:21, 27 January 2014 (UTC)[reply]

However, out article on Atomic physics does make a distinction from Nuclear physics and it is exactly as StuRat supposes above. Nuclear physics is addresses only the nucleus and atomic physics addresses the with the whole atom. But that seems to be a technical distinction and both articles lack citations on the difference. Richard-of-Earth (talk) 11:34, 27 January 2014 (UTC)[reply]

Kriegslok

Many railfans know how to distinguish different types of steam locomotives by sound; e.g. the "Shay" narrow-gauge engine puffs at six beats to the bar, the "Lord Nelson class" express engine at eight beats to the bar, many of the Gresley locomotives have a syncopated beat because of the derived valve gear, etc., etc. So can anyone describe to me how a German Kriegslok freight locomotive sounds, especially in comparison to a French freight engine? Thanks in advance! 67.169.83.209 (talk) 06:14, 27 January 2014 (UTC)[reply]

Youtube has many examples you can listen to such as [1]. Spinning Spark 11:19, 27 January 2014 (UTC)[reply]

Oh, and don't miss this wartime propaganda film about production of the locomotive. Spinning Spark 11:26, 27 January 2014 (UTC)[reply]

Thanks! It sounds to me like the sound of the exhaust is rather sharp -- which would make sense because to simplify production, the pistons probably weren't chamfered like they are in many other steam locomotives. 67.169.83.209 (talk) 05:31, 28 January 2014 (UTC)[reply]

download offline medical division content only

Dear Sir I am a pharmacist and I wish to download offline data of wikipedia of what is concerning the medical section. How can I download only that speciality. Do I have to download the 9 GB zm file or there is a file for each devision that can be downloaded. Thank you — Preceding unsigned comment added by 62.114.71.69 (talk) 13:17, 27 January 2014 (UTC)[reply]

Each Wikipedia article has a "download/print" section which you can use to download individual articles. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:43, 27 January 2014 (UTC)[reply]

Downloading one article at a time will take a very long time. A database download should be a lot simpler. Once you have the full database you can use queries and filters to select the files you want to keep. Roger (Dodger67) (talk) 15:45, 27 January 2014 (UTC)[reply]

You can also create a "book" with a selection of pages. There is a link in the left column of the page. You can add an entire category to it, then export in several formats including PDF. Katie R (talk) 17:38, 27 January 2014 (UTC)[reply]

See Book creator for details, ~~see also: categories~~[not very helpful here] ~:71.20.250.51 (talk) 00:25, 28 January 2014 (UTC) [Modfied:00:29, 28 January 2014 (UTC)][reply]

Mixing powdered cinnamon into water

Today I was trying to stir ground cinnamon into my mass market triple shot iced coffee. I noticed the ground cinnamon just did not want to blend into the coffee. It wanted to float on top and resisted mixing. What's this property called? --Navstar (talk) 23:01, 27 January 2014 (UTC)[reply]

[Banned user]

Is there an element of hydrophobicity involved? Dbfirs 23:17, 27 January 2014 (UTC)[reply]

[Banned user]

I believe most chemically inert, water-insoluble powders can act similarly hydrophobic. See the pictures at Superhydrophobe, but think about the powder in the liquid instead of the liquid on a rough surface. Wetting is the converse process, and also has some good pictures. When you have granular material instead of surface roughness discussed in the articles, then clumps can form where the outside is wetted and cohesive, but the inside stays dry, and this makes it even more difficult to mix into an homogenous suspension. I can't find a WP article that specifically discusses the hydrophobic behavior of powders, but Mixing_(process_engineering) alludes to some of these issues. SemanticMantis (talk) 23:47, 27 January 2014 (UTC)[reply]

Now for some practical suggestions for your case:

1) Mixing works better at higher temperatures, so mix in the cinnamon to hot coffee, then add the ice. Of course, if it's already iced when you get it, this option is out.

2) Pour a small portion of the coffee into a large container with a top, add the cinnamon, seal the top, shake well, then open it up and add the rest.

3) Use a liquid cinnamon flavoring agent instead of powered cinnamon. Of course, this is likely to contain sugar and other items you may want to avoid. StuRat (talk) 00:44, 28 January 2014 (UTC)[reply]

(Practical solutions to avoid situation described)

4) Simply add the cinnamon with the ground coffee before you brew it. —(For iced coffee, brew double-strength before adding ice)

5) Use oil of cinnamon (one or two drops); but, should add cream/milk to act as an emulsifier. ~E:71.20.250.51 (talk) 01:15, 28 January 2014 (UTC)[reply]

Note that 5 is a variation on 3, only 3 already has the emulsifier mixed in. StuRat (talk) 02:20, 28 January 2014 (UTC)[reply]

My grandmother used to sometimes add a few drops of brandy to dried spices. Presumably, as alcohol is a wetting agent this helped but I can find no references. So maybe this is Folklore. Mind you, as your end point is a nice cup of iced coffee, then a dollop of brandy can only improve things.--Aspro (talk) 17:06, 28 January 2014 (UTC)[reply]

Yes, I think that would help form a tincture of the tasty chemicals. There's a few things going on here. In cinnamon, there are all kinds of volatile organic compounds that carry flavor, that are soluble in water/alcohol. But most of the cinnamon powder, by weight or volume, is insoluble cellulose. SemanticMantis (talk) 17:22, 28 January 2014 (UTC)[reply]

That's is a good point. As cinnamon is bark consisting of cellulose and lignite, then even finely ground it will just float. Infusing the coffee with a cinnamon stick (and then removing) might be what the OP is after. However, if it is filtered coffee, the filter will remove those grounds. Still, the OP mentions “mass market triple shot iced coffee”. Well, I don't know what mass market coffee is, unless he means something like nescafé in which case its is like trying to [make a silk purse of a sow's ear]. Tap-water is a better re-hydrant. So, in short he may just need to infuse a suitable sized bit of cinnamon stick for a few minutes in hot water and then add the coffee to that water infusion.--Aspro (talk) 20:07, 28 January 2014 (UTC)[reply]

Yep, most of the flavor of cinnamon comes from compounds that are only sparingly soluble in water, but are much more soluble in alcohol: mostly cinnamaldehyde and some ethyl cinnamate. The former is widely used as a flavoring agent. TenOfAllTrades(talk) 03:31, 29 January 2014 (UTC)[reply]

January 28

Stereo sound from one ear bud

In the movie, Her, the main human character has single earpiece (a futuristic Bluetooth-type earbud) he uses to interact with his phone/computer. It's implied that he can listen to stereo audio. Obviously, we don't have this technology today (at least not at the consumer level). But how would something like this work? --Navstar (talk) 01:33, 28 January 2014 (UTC)[reply]

Well, if the single ear bud blocks ambient noise and delivers one channel (either left or right), and you have another speaker somewhere in the room with the other channel playing, that could work. Others in the room would hear mono, while the person with the ear bud would hear stereo. StuRat (talk) 02:17, 28 January 2014 (UTC)[reply]

It does not work. It's just a prop in a movie. 202.177.218.59 (talk) 02:21, 28 January 2014 (UTC)[reply]

The Q wasn't whether the prop really works, it was if there is any way such a system could work. StuRat (talk) 02:39, 28 January 2014 (UTC)[reply]

There is a technology (see Sound from ultrasound) to direct sound to appear from a point in space that's remote from the equipment that produces it. There have been efforts to use this in advertising and as a military weapon. Imagine you're walking with a crowd of people in a shopping mall and some facial recognition software recognizes you as a frequent shopper at one of the stores...a directed sound system could whisper into your ear: "Hi Navstar! There's a special offer waiting just for you at our store, over to your right."...and nobody but you would hear it. The sound system could follow you around in three dimensions, beaming sound into your ears no matter where you go. It's a horrible idea - but advertisers love it.

So I suppose, with enough advanced technology, you could wirelessly beam sound into people's ears without needing ear-buds at all...and certainly it could be possible to have a device that fits in one ear transmit sound to the other ear using that kind of mechanism. Of course this is all science fiction right now - but it's definitely not impossible. SteveBaker (talk) 02:56, 28 January 2014 (UTC)[reply]

Don't know what show so not sure what the prop is. But human sound perception of sound is more complex that just L/R. If you just had a left ear, receiving the same signal delayed and modulated might mimic some aspects of reflections and source. One eyed people can drive, not because they have binocular vision, but because of cues they perceive give them a form of depth perception. --DHeyward (talk) 03:05, 28 January 2014 (UTC)[reply]

I agree with you...but your one-eyed driver analogy could use some explanation. Our ability to estimate distances uses at least six different mechanisms (focal distance, binocular accomodation, parallax from small head movements, relative size of object compared to those at a known distance and image size on the retina of a known-sized object, atmospheric attenuation). A person with only one functioning eye can still use five out of those six methods. Furthermore, the binocular accomodation method (which is the one they don't have) is only effective over a range from a couple of feet out to maybe 20 or 30 feet. Beyond that, it has little value.

It's not clear to what degree effects like phase lag and relative sound amplitude have on directional hearing, and it gets more complicated still when sounds are able to reflect off of the bones of the skull and are refracted by the higher speed of sound through the brain compared to the air. HOWEVER, when sound is fed to you through two earbuds, then ALL of those tricks are wiped out - or worse, they are subverted to making it even more obvious to the listener that this isn't "real" surround sound. So the analogy to the one-eyed driver who has lost only one of the available perceptual mechanisms - isn't really correct. SteveBaker (talk) 20:10, 28 January 2014 (UTC)[reply]

You're right. Still I suspect adaptations by individuals are beyond interpretation. I suspect slight adjustments of head position would allow perception of location that is not explained by a fixed position. A differential analysis by the brain of 0 degrees and 45 degrees of the same source tone would easily isolate location and possibly distance. Coupled with the data of moving the head to adjust amplitude makes me think the brain is more sophisticated than a 2 input DSP. --DHeyward (talk) 06:23, 29 January 2014 (UTC)[reply]

Finding milliamps of electric batteries (Ni-Cad) used in portable drills (such as a Black/Decker 12 volt unit from Lowes)

I have a few portable drills several years old that are missing battery charges. Buying (if available) would be costly and would make no sense. I have 12 volt DC plug in transformers with various ratings from 300 ma to 3 -4 amp. I will experiment by attaching a transformer to the internal battery posts but need some idea of amperage range. I could insert a pot and start at the low range but a bit stuck on risk of damaging motor. Can anyone advise me on getting unstuck or do I remain within my Scottish clan which include Gearloose McDuck. Thans — Preceding unsigned comment added by 108.195.4.48 (talk) 04:38, 28 January 2014 (UTC)[reply]

The current drawn will depend on the motor of the drill and also on the load in use. I would expect that under heavy load the drill might require five or even ten amps, so your transformers might be inadequate and might be overloaded. Another suggestion would be to connect your drills to a car battery (or one of those handy 12v portable booster batteries), but you will need to include some protection against short circuits. (If it is only the charger that is missing but the battery is OK then almost any 12v DC charger will work, but limit the current to one tenth of the total capacity i.e. charge at the "ten hour rate", or to the rated current of the charger if this is lower. The battery is unlikely to hold an adequate charge if it has been unused for years.) Dbfirs 11:19, 28 January 2014 (UTC)[reply]

F-102 safety record

Hello all, I've just watched an amateur "documentary" film that alleges that the F-102 Delta Dagger had suffered "literally HUNDREDS of... crashes" due to the bad low-speed handling characteristics of its delta wing; however, I strongly doubt this claim, because had that been the case, most if not all F-102s would have crashed at some point. I tried reading the article, but it says nothing about the type's safety record. Does anyone happen to know whether what the film says is true, or whether it's just another piece of anti-military bullshit? 67.169.83.209 (talk) 06:47, 28 January 2014 (UTC)[reply]

The F-102 does seem to have had a high loss rate: "Of the 875 F-102A production models that entered service, 259 were lost in accidents that killed 70 Air Force and ANG pilots." [2] AndyTheGrump (talk) 07:07, 28 January 2014 (UTC)[reply]

Thanks! So, the "literally HUNDREDS" part was somewhat of an exaggeration, because that phrasing connotes at least 300-400 losses -- at least, the way I see it. 67.169.83.209 (talk) 07:17, 28 January 2014 (UTC)[reply]

Well, to me 'hundreds' would suggest 'at least two hundred'. Actually though, the more meaningful figure may be the hourly accidental loss rate: 13.69 per 100,000 hours flown - three or four times the figures for most current U.S. fighters (same source as above). Modern zero-zero ejection seats will probably have reduced fatality rates considerably too. AndyTheGrump (talk) 07:39, 28 January 2014 (UTC)[reply]

Note that 1950s high performance interceptors were all a lot more dangerous than their modern counterparts. I can't find any comparable figures, but the Lockheed F-104 Starfighter was known as "The Widowmaker" and its British contemporary, the English Electric Lightning, was given the soubriquet "The Flying Coffin" (see List of accidents and incidents involving the English Electric Lightning). The F-104 initially had an ejector seat that shot the pilot down through the floor; not only did this make ejecting at low altitude impossible, but in case of a wheels-up landing, the ejection hatch was ripped off and soil was scooped up into the cockpit, burying the pilot alive. Alansplodge (talk) 13:58, 28 January 2014 (UTC)[reply]

I can't put my hands on the figures but during the two years of the battle of Britain, more than twice the number of aircraft where being lost in training accidents than in combat. It was not so much that the aircraft per se were dangerous but the were being flown to their very limits. Thus, often escaped their Flight envelope. When were you last on a Boeing Jumbo, where the pilot treated you to a few low altitude barrels rolls and a loop de loop? Simulators have done a lot for safety and pilot/crew survival. Back in the days of the English Electric Lightning, learning by trial and error, often lead to a short career if one got it wrong -just once. It wasn't the aircraft's fault nor that of the pilot. It was the need to be better skilled than the enemy -should that day come to prove it.

When I worked on flight simulators, our scenery artists were instructed to put invisible barriers under all of the bridges in order to persuade pilots (who seemed unable to resist the temptation to fly under them) from coming to believe that they could do so safely! The temptation to push that envelope is everywhere in the rather extreme "Type A personalities" of many fighter pilots. SteveBaker (talk) 21:32, 29 January 2014 (UTC)[reply]

Note that "literally HUNDREDS" of crashes may be referring to a different number than the "259 lost in accidents". Many crashes leave the aircraft in a repairable situation - in which case it's not considered to be a "loss" - which implies that the airplane is too severely damaged to return to service. With the near-certainty that there were more "crashes" than "losses" - it's seems almost certain that more than 300 "crashes" have occurred - with 5 our of every 6 crashes resulting in a loss and one out of 6 resulting in a repairable plane. However, I agree with Andy - even 200 does indeed count as "hundreds" - it's basic English language - the word "hundred" means 100, stick an 's' on the end to form a plural and all you need is more than one "hundred" - so 200 certainly counts as "hundreds". If the phrasing had been "several hundred" - then maybe I'd agree that this expresses a number over 300. SteveBaker (talk) 20:00, 28 January 2014 (UTC)[reply]

Wood burning stove/ Creosote build-up

Will throwing an aluminum beer/soda can in my woodstove help reduce the creosote build-up? Donna — Preceding unsigned comment added by 2001:5B0:21FF:2CF0:0:0:0:32 (talk) 16:20, 28 January 2014 (UTC)[reply]

Do you run your wood stove mostly at low heat with the damper in most of the time. The relative coolness of the stove under these conditions will encourage tars to condense out. Forget chemical fixes. Occasionally, run the stove at a high temperature to burn off these residues. (what type of flue do you have? You don't want to get a chimney fire in the process.)--Aspro (talk) 17:15, 28 January 2014 (UTC)[reply]

It looks like that would probably help creosote to flake off , but it is not usually a recommended as a safe/efficient method. More of an "old country fix." Here's some discussions I've found [3], [4], [5]. There's a lot of people saying it works, and here's a video that claims to show evidence [6]. I've never tried this personally; proceed at your own risk. Also note that chimney fires are very dangerous. Cleaning creosote can prevent them, but attempting to burn something much hotter than wood could also start an nasty fire, especially if you have lots of built up creosote. SemanticMantis (talk) 17:17, 28 January 2014 (UTC)[reply]

I have a lot of respect for folk wisdom. So I have found this:Aluminium fume The predominant risk associated with aluminium welding is exposure to ozone.. Ozone would indeed degrade tars. My folk-wisdom of a hot-burn dates back to before aluminium cans, when pepsi and coca cola came in steel cans and had to opened with one of these things. [7]. Still, I am open to new ideas and methods, indeed - I don't need aluminium cans anyway as I have adopted modern central heating. It seem to be only in counties like the US that have to resort to soda cans ;-)--Aspro (talk) 20:45, 28 January 2014 (UTC)[reply]

Cola cans without pop-tops ? I didn't know they ever made such a thing. I though it only came in bottles before the pop-top. StuRat (talk) 23:33, 28 January 2014 (UTC) [reply]

Here is a photo [8] of the two triangular holes in the steel can that had to be made with the tool linked to above. The other end, lifted off the crowns on bottles. Oh happy days, one could fill up the Pontiac, grab a coke and still get change from a five dollar bill.--Aspro (talk) 00:08, 29 January 2014 (UTC)[reply]

Having just reread what I wrote, I wondered if my memory was playing tricks on me -but in my mind's eye I can still see those five dollar bills in my hand. So I looked it up. http://www.google.com/url?q=http://oregonstate.edu/cla/polisci/faculty-research/sahr/gasoline.pdf&sa=U&ei=tEfoUsmwFMbR7Ab71IGABQ&ved=0CDsQFjAF&usg=AFQjCNFcGVDyqTbHh1wdORRrFPn9le_yJQ
Yes, gas was less the 30 cents a gallon, so one could fill up the auto for the week ahead and get a coke for oneself and my seat-cover and still get change from a five dollar bill. And the coke came in a steel can that we had to open with one of those can openers--Aspro (talk) 00:47, 29 January 2014 (UTC) [reply]

I'm familiar with that method of opening cans, as I've used it on cans of oil (although the air hole doesn't need to be nearly as large). I've just never seen it applied to cola. (I wonder how many absent-minded mechanics poured their Coke into the car engine instead of motor oil.) What would be the advantage of that kind of can over a bottle ? Easy opening pop-tops seem to be the main point of cans, to me. StuRat (talk) 00:57, 29 January 2014 (UTC) [reply]

I've had one of those all my life, and have only ever used it on tomato juice cans. I have no idea why every other beverage around here has some sort of "hands-only" design. Makes even less sense considering tomato acid reacts with the metal after opening, and it's suggested to put it in a glass or plastic pitcher. InedibleHulk (talk) 01:07, January 29, 2014 (UTC)

Of course back when you could fill up your Pontiac for $5, the gas consumption would have been so appallingly bad that you wouldn't get much further than a modern car does on $30...but that's another story! SteveBaker (talk) 21:27, 29 January 2014 (UTC)[reply]

Aluminum fumes are toxic, so I don't recommend this method. StuRat (talk) 23:33, 28 January 2014 (UTC)[reply]

You'd probably also need a very hot fire and a bunch of cans. Having a very hot fire in a creosote-laden chimney isn't smart. Best to just buy one of these "logs". I can vouch for them. InedibleHulk (talk) 00:16, January 29, 2014 (UTC)

I can't find an official ingredients list of that product online, but some of my linked discussions above say that they contain aluminum in some form. It should say on the package. SemanticMantis (talk) 15:17, 29 January 2014 (UTC)[reply]

It might. I burned my last package before Christmas, right after the log. In any case, the recipe is certainly different from beer cans, and it burns at a much lower heat. Cans are cheaper, though. For now. InedibleHulk (talk) 23:36, January 29, 2014 (UTC)

Cold hands feeling like they're pulsating

When I was kid at school in the UK in the winter, we had to play football which I had no interest in. My hands would become exceedingly cold and eventually I would feel this very unsettling, exaggerated pulsating. It felt like I should be able to see the pulsating but thankfully did not. Is this usual? I would never allow my hands to reach anywhere near that temperature now so I don't know (or much mind) whether it still (would) happens. --78.148.110.69 (talk) 20:20, 28 January 2014 (UTC)[reply]

We don't give medical diagnosis here on Ref Desk and this is what your really asking. However, I can give you some pointers that you can run by your General Practitioner for reassurance. Yes, it is common if the pulsation is in the wrist and you are terribly cold. In less server weather extremes it might get diagnosed as Carpal tunnel syndrome. It is worth running by your GP because as though you don't suffer from it now, one of your children or grandchildren might suffer from it and you can inform their parents that is they are not complaining about a trifle. Good gloves, jumper etc mitigates to discomfort – but the condition first, has to be recognized as real, so that the the school allows extra clothing on the football field.--Aspro (talk) 21:16, 28 January 2014 (UTC)[reply]

It is not a medical question! I absolutely will not make an appointment to see my GP (free on the NHS but that doesn't make it okay to waste their time) to ask him about a sensation I experienced 14/15 years ago! If I pricked myself sewing and a drop of blood formed on my finger, would it be a medical question if I asked about its colour or why it clots? To clarify, it was the main body of my hands, not my wrists, and the grass field was frozen which is pretty extreme weather to be standing around outside in shorts and a crappy rugby jersey. 129.215.47.59 (talk) 17:15, 29 January 2014 (UTC)[reply]

I'm not asking for a medical diagnosis; I want to know of human physiology. If I had the mind I have now, I'd have told the teacher to speak to my lawyer (an idle thread) and have gone inside. I think the temperatures my extremities experienced were beyond normal. No-one can "force" me now to stand outside in inappropriate clothing at the age of 29. Also, it wasn't my wrists but the flesh of my hands in which I felt this. If I'm the only one to report this then fine, but I suspect others know what I've experienced and maybe understand why. Maybe the cold affects pressure sensors in this way. 78.148.110.69 (talk) 22:07, 28 January 2014 (UTC)[reply]

RE: 'No-one can "force" me now to stand outside in inappropriate clothing at the age of 29' ... just don't join the military. School coaches aren't the only sadistic people. StuRat (talk) 23:37, 28 January 2014 (UTC) [reply]

Did you try tucking your hands into your armpits? That's usually a good way to warm them up. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:44, 28 January 2014 (UTC)[reply]

I've just realised that by "football" the OP probably means that strange sport where you aren't allowed to do anything with your hands, except letting them just hang there to get frozen. Though Bugs's suggestion might be on the right track. HiLo48 (talk) 23:47, 28 January 2014 (UTC)[reply]

What? You realized that by football, they meant a sport where they use their feet? WTF is your point? I'm a fan of football, not soccer, but your response makes no sense to me. --Onorem (talk) 23:55, 28 January 2014 (UTC)[reply]

Well, it's obvious that not being allowed to do anything with one's hands as part of the game is going to make this problem worse. Where I come from "football" means a game with big involvement of both the feet and the hands. My statement was true. I didn't realise initially that the game in question was probably "soccer". HiLo48 (talk) 00:01, 29 January 2014 (UTC)[reply]

The OP geolocates to, and specified, the UK - hence, football would equate to soccer. Obviously, the hands are required in certain parts of the game: goalkeeping, throw-ins, etc. I was just wondering if the OP had tried tucking his hands, or if he found that impractical. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:22, 29 January 2014 (UTC)[reply]

When you're cold, blood vessels near exposed skin contract more than in warmer parts. The pulsing is your blood squeezing through tighter spaces there. At this point, you're probably close to or at frostnip, then frostbite. InedibleHulk (talk) 01:19, January 29, 2014 (UTC)

That sounds like what I've usually heard about exposure to cold: If your extremities are in pain, they're still in pretty good shape. Once they go numb, you're in trouble. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:41, 29 January 2014 (UTC)[reply]

You get some leeway time between numb and serious tissue damage. Not long in very cold weather, probably a fair window in England. But it's best not to wait, because thawing hurts a lot more than freezing. InedibleHulk (talk) 02:40, January 29, 2014 (UTC)

A key question would be whether it was above or below freezing. Is it possible to get frostbite if the temp and the wind-chill are both above freezing? Also, would being "interested" in the game help the OP stay warmer? ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:59, 29 January 2014 (UTC)[reply]

Can't get frostbite above zero, but the vessels will still contract somewhat at whatever temperature a body decides is too cold. Gotta figure an interested player will play harder, and that'll warm him up. Thinking about anything intently should create some warmth in the brain, but the humanly imperceptible and virtually insignificant kind. InedibleHulk (talk) 03:38, January 29, 2014 (UTC)

Just passing by. Anyway, a good advice : if you smoke, quit NOW ! (are you aged 29 ? are there any such cases in your family ? did you hear of Raynaud's syndrome ? ). But I must stop, of course ...Good luck to you Arapaima (talk) 09:10, 29 January 2014 (UTC)[reply]

See: Raynaud's phenomenon Richerman (talk) 10:52, 29 January 2014 (UTC)[reply]

Thanks guys but I don't smoke and it really isn't a medical issue. My extremities do not discolour like that and I'm not prone to it. It was just poor child care (I probably should have been sent to run laps around the field but didn't think to do this myself because I was a stupid kid) and I still think I was experiencing a normal phenomenon. I will scour the Internet for answers and will report back if I find anything. 129.215.47.59 (talk) 13:35, 29 January 2014 (UTC)[reply]

It's hard to answer about "unsettling, exaggerated pulsing". I mean, I always feel my pulse throughout my body, and of course it's stronger after exercise, so why would it be unsettling or tied to cold weather? Yet I've heard people assert that they don't feel their pulse, even to the extent of saying they don't feel their own heartbeat, even to the ludicrous extreme of seeing them physically taking their own pulse with their fingers. That I don't understand, so we should clarify whether you fall into that category and if so try to get to the bottom of the more interesting question of why you wouldn't feel your pulse at other times. Wnt (talk) 17:45, 30 January 2014 (UTC)[reply]

In my own case (which may be similar or not, I smoke like a chimney, but don't seem to have many Raynaud's symptoms), there's a distinct difference between the smooth and subtle "normal" pulse and the sharp, squeezing, slightly electresque feeling when I work in the cold. The harder my heart beats, the sharper the feeling, but it's only ever in the hands (probably would affect my feet, if I ignored my boots and socks like gloves). I haven't felt anything like it in warm weather (so far), so I figure my issue is cold constriction. InedibleHulk (talk) 22:59, January 30, 2014 (UTC)

January 29

Danny DeVito health problem

Hello Learned Ones ! I am following my program "Do now what you never had time to do in the past years" & just watched Friends (season 10) 11th episode "The One Where the Stripper Cries" (Feb. 2004) . I was flabbergasted at Danny DeVito 's performance as a distorted and aged stripper. I also brooded (as a M.D., & from a medical point of view) about his legs problem : hidden by the pantaloon he kept on, they seemed to me very thin, paralysed, & not flexing, maybe held up by stilts, while his torso seems about normal. WP does not give any hint about his ailment. Can somebody tell me what it is ? Poliomyelitis sequel ? Neural horse-tail malformation ? General osteo-formation disease ? Anyway, hats down in front of the man's stamina & mind power ! Thanks beforehand for your answers. T;y. Arapaima (talk) 09:02, 29 January 2014 (UTC)[reply]

Multiple_epiphyseal_dysplasia (See: Multiple_epiphyseal_dysplasia#Prominent_people_with_this_condition No inline citation.) 196.214.78.114 (talk) 10:24, 29 January 2014 (UTC)[reply]

I'm struggling to find a reliable reference. This one is a "scholarly" one. See page 5: http://eresearchau.files.wordpress.com/2013/02/eresearch-2013-presentation_craig-mcnamara.pdf 196.214.78.114 (talk) 10:52, 29 January 2014 (UTC)[reply]

Yes! my 3d hypo. was about right ! Thanks a lot 196.214.78.114 ! Arapaima (talk) 11:03, 30 January 2014 (UTC)[reply]

Preferred format for Gene Wiki articles

Hi,

I am an instructor of a bioinformatics course at the University of Minnesota. We write Wikipedia articles each year on human genes of unknown function for which there are usually only stubs at the outset. I forwarded a message from someone going by "Boghog" (Boghog (talk) 17:35, 13 May 2013 (UTC) asking me to contact him so that I could ensure my students' pages are more compliant with the format of other Gene Wiki articles. I'm not sure how to contact him but perhaps you could help me do this. He gave no email address. Thanks!

David Matthes University of Minnesota — Preceding unsigned comment added by 134.84.13.8 (talk) 20:04, 29 January 2014 (UTC)[reply]

You can post a message for him at User talk:Boghog (click on the "New section" tab and enter an appropriate header for your message). This sort of question is really more appropriate for the Help Desk (but there's nothing wrong with asking it here). Tevildo (talk) 20:43, 29 January 2014 (UTC)[reply]

Bed rest

What's the minimum required dose of non-bedrest to prevent permanent damage? (On Earth). The nasa bed rest study apparently causes permanent damage. 12.196.0.56 (talk) 22:20, 29 January 2014 (UTC)[reply]

Damage from what? Can you please explain your question more clearly? Are you asking about bed rest (header) or non-bed rest (question)? -- Jack of Oz ^{[pleasantries]} 22:51, 29 January 2014 (UTC)[reply]

Pending clarification, one big problem with being bedridden is getting nasty skin problems, which can lead to further infection, etc. If you're interested in that, see bed_sore#Prevention, and the references therein. Also, the US government has a comparison of preventative guidelines here [9]. SemanticMantis (talk) 23:28, 29 January 2014 (UTC)[reply]

Going by this:[10] it suggest a max of about 9 hours Per diem.I.e., not bed-rest but sleep--Aspro (talk) 23:37, 29 January 2014 (UTC)[reply]

Damage from anything, but they get bone and maybe muscle loss don't they? Though maybe muscle cells don't die (I don't know) so you could regain lost muscle mass? 12.196.0.56 (talk) 23:28, 30 January 2014 (UTC)[reply]

Sequence

Is this the correct sequence; gamete, zygote, morula, blastocyst, embryo, fetus? If so, are there any which i have missed out on?

Details of embryogenesis can change, depending on the species. If you are interested in humans, see Human_embryogenesis and Prenatal_development (which is human-centric). Terminology may vary somewhat, but our article says it's an embryo from first cell division until birth. In that sense, zygotes, morulae, and blastocysts are all embryos. Fetus, however says that embryo-hood ends and 9 weeks in humans. SemanticMantis (talk) 23:38, 29 January 2014 (UTC)[reply]

The sequence is correct, but you haven't mentioned gastrula or neurula. μηδείς (talk)

Not to my reading. An embryo can be in the zygote or morula stage, but the way the OP writes it seems to imply that a blastocyst turns into an embryo (i.e. it was not an embryo before), which is contrary to our article's explanation. SemanticMantis (talk) 15:45, 30 January 2014 (UTC)[reply]

Yes, I see your point. Kind of like listing New Years Eve, January, February, Winter, Spring. μηδείς (talk) 18:05, 30 January 2014 (UTC)[reply]

Organic compounds

Why is octanol thicker than octane? At least by boiling point, if not actually thickness. Long enough alcohols become solid even at body temperature. Is there like a gel phase or do they just suddenly freeze? What would it be like to swallow or gargle various pure alcohols? I'm not going to try it (okay, I put 70% isopropyl in my mouth once - My palate instantly shriveled like a prune). Even if it'd just be shriveling and pain at least tell me what the consistency would be like. — Preceding unsigned comment added by 12.196.0.56 (talk) 22:41, 29 January 2014 (UTC)[reply]

The reason for the higher freezing and boiling points is because octanol is a polar molecule which exhibits a fairly high degree of hydrogen bonding. As for what's it like to swallow the stuff -- I don't know, and I don't want to try. 67.169.83.209 (talk) 07:35, 30 January 2014 (UTC)[reply]

Alcohols generally have a lot in common regarding their toxicity and effects, with the bigger ones generally being worse. I remember Russians who had lived under Gorbachev told me that some people there had used to drink isopropanol, at about half the dosage of ethanol. I assume they diluted it - even ethanol is dangerous to drink at high purity levels. gamma-hydroxybutyrate (GHB) is another alcohol that had a fad of popularity in the 1990s. After an immense amount of hype on the part of sellers and demonization on the part of authorities, the net result was that they banned a formerly very useful industrial solvent (I remember reading the parent cyclic compound could dissolve a shoe, not sure what brand). You can look up the MSDS for octanol from various sources - they tend to be vague and have scanty information, but apparently it causes vomiting, respiratory depression ... stuff you'd expect from an alcohol. It's very difficult to look up the toxicity in better sources because many toxicity studies are done using it in a purely technical capacity. For all I know, with a good PR team and some ambition somebody might make the next big fad out of it, but aside from the money to be made this has nothing to be recommended. Wnt (talk) 17:21, 30 January 2014 (UTC)[reply]

January 30

Standing water in my workshop not freezing at below 32 degrees

I live in detroit and my workshop as i measured today clocked in at around 24 degrees fahrenheit, but all of the standing water in cups and metal buckets that were there overnight were not ice. I do not think it has anything to do with pressure as detroit is slightly above sea level i think, and the decrease in pressure would seemingly effect the freezing point in the opposite direction, though maybe I am wrong.

I used an infrared laser temperature reader so i think the readings are pretty accurate, i measured the containers and the water itself and they were the same temperature.

The only other variable i can think of is that because the water was from the tap, that some minerals or chemicals are effecting the freezing point.

Any insight would be nice. 70.210.65.5 (talk) 00:23, 30 January 2014 (UTC)[reply]

That's not cold enough for water with salt or alcohol in it to freeze. Have you used either of those in your containers lately? InedibleHulk (talk) 01:42, January 30, 2014 (UTC)

Actually, according to that source, "Any foreign substance added to the water will cause a freezing point drop. For every mole of foreign particles dissolved in a kilogram of water, the freezing point goes down by roughly 1.8°C". InedibleHulk (talk) 01:44, January 30, 2014 (UTC)

There was no ice or alcohol in it, fresh water that was sitting in a metal pail, and a few in coffee cups. I guess my shop is pretty dusty so maybe the water is really full of dirt and stuff.

70.210.65.5 (talk) 01:49, 30 January 2014 (UTC)[reply]

I suggest you calibrate your temperature reader. Put some ice out in a plate, and wait for it to start melting. At that point it will be 32 degrees F. Measure its temperature, and see if you get a temperature below 32 degrees. If so, the device is inaccurate. μηδείς (talk) 01:56, 30 January 2014 (UTC)[reply]

Could be some corrosion going on in the bucket, or in your pipes, little bits dissolving. 2 moles per kilo would be enough, and that's not a lot to see with your eyes. My tap water tastes coppery here and there. Maybe dust. Maybe a miscalibration. But rest assured, it's not black magic or some glitch of global warming. If it gets to -21 C (-5.8 F) and still acts up, then maybe call a priest. InedibleHulk (talk) 04:05, January 30, 2014 (UTC)

Water doesn't cool very fast when it's near freezing. I've been experimenting with time-lapse videos of water freezing, and it takes about eight hours for water in a soda can to start freezing from a temperature of 40F. --Carnildo (talk) 04:19, 30 January 2014 (UTC)[reply]

That's correct. Water has a high heat capacity and also a high Enthalpy of fusion, so a surprisingly large heat flow is needed to freeze your cups and buckets. In the absence of significant airflow, freezing will take a long time. I also suspect that the temperature of most of the workshop remained much higher, for most of the night, than your measurement in the early morning, so if rate of loss of heat was proportional to temperature difference, this would not be as large as one might expect. (Leaving the doors to your workshop open on a cold windy night will speed up the freezing process because convection carries away heat more quickly than radiation.) It would be interesting to put a recording thermometer in your bucket to see how slowly the temperature falls. Dbfirs 11:23, 30 January 2014 (UTC)[reply]

Infrared laser thermometers perform most accurately when directed at a matt black surface because the emissivity of the surface measure has a bearing on the measurement. You can improvise a matt black surface using a black marker pen on masking tape. Be sure to allow the tape to come into equilibrium with the object/environment. 78.148.110.69 (talk) 09:00, 30 January 2014 (UTC)[reply]

Still water also supercools before freezing on many occasions. shoy (reactions) 14:30, 30 January 2014 (UTC)[reply]

Delta Dagger, cont'd

As far as I know, the F-102 Delta Dagger had never seen actual combat in its intended role, which was that of a supersonic interceptor for use against bombers -- instead, it was employed in Vietnam as an escort fighter (unsuccessfully) and for ground attack (with surprising success). So, the only data that could indicate whether it would have performed well in its intended role comes from training combat exercises like the William Tell air-defense exercise (especially ones with live-firing of missiles); however, the article doesn't include this data, nor any links to it. Where can I find the data? (If you want to know, it's that "documentary" again -- what it asserts is that the Deuce was a piece of junk and a total waste of taxpayer money, whereas I'm trying to prove that it would have made a good interceptor, but it just wasn't designed for anything else.) 67.169.83.209 (talk) 02:01, 30 January 2014 (UTC)[reply]

I presume you're aware that those statements you make at the end aren't necessarily contradictory? Nil Einne (talk) 07:27, 30 January 2014 (UTC)[reply]

Will you PLEASE cut out the soapboxing and just tell me where I can find the training exercise stats (in particular, stats about the percentage of successful intercepts)? 67.169.83.209 (talk) 07:32, 30 January 2014 (UTC)[reply]

I found ANG Team Winners: Air Force Flying Competitions which only gives ANG winners and no other details. I also found SSP - In Action 199 - F-102A Delta Dagger but haven't found time to read through it. Alansplodge (talk) 17:20, 30 January 2014 (UTC)[reply]

Well, I've actually read the SSP booklet, but it doesn't have this particular info (although it does have a few stats about "Operation Stovepipe", which was that operation where they used the Deuce for ground attack). Guess these stats are harder to find than I thought. Thanks for the effort anyway, and if anyone finds the interception %, please let me know! 67.169.83.209 (talk) 06:32, 31 January 2014 (UTC)[reply]

Reusing turpentine substitute

I have some turpentine substitute that I used to clean Tip-ex (white-out/correction fluid) off some plastic templates. Previously having used this to clean paint brushes, the paint fell to the bottom after several days storage, allowing me to decant the liquid for re-use. In this case, it appears that some grey residue has formed in the bottom of the jar but the liquid remains white (light grey, really). Am I right in thinking this will never precipitate out? Perhaps I can just use the liquid in place of firestarters as accelerant for igniting wood in our chiminea? You're not meant to pour it into drains but since it's just a bunch of hydrocarbons, burning it shouldn't be more environmentally unfriendly than burning wood in a chiminea anyway, right? — Preceding unsigned comment added by 78.148.110.69 (talk) 08:35, 30 January 2014 (UTC)[reply]

No one here will take any responsibility for recommending any off-label usage of such stuff. You do what you gotta do, but realize that no one here told you it was a good idea. --Jayron32 15:15, 30 January 2014 (UTC)[reply]

First, we should establish that you are speaking, I presume, of white spirit / "mineral turpentine" etc. Our article is saying that that is a "light grade of kerosene" usable in stoves, though I didn't verify this. Then there's our article on Tipp-Ex which says that the older formulation used until 2000 contained 1,1,1-trichloroethane. I'm not confident to estimate the chance this could be volatilized in a wood stove to the point of becoming dangerous, though I'd think that its evaporation right after use would be the bigger problem. My feeling though is that if this turpentine has been used and reused your biggest concern should be for other unknown/unspecified ingredients - lead paint for example. See oil paint for a whole palette of possibilities. (I'd tend to think that many of these compounds would have precipitated out in large degree, but I'm nowhere near ready to make a blanket guarantee!) Wnt (talk) 16:59, 30 January 2014 (UTC)[reply]

I regularly use old white spirit for lighting fires and have never had any problems, but we cannot make recommendations on health and safety except to say that, if you are go ahead, "use with care". I still have some 1,1,1-trichloroethane and can confirm that it evaporates very quickly (and even from a tightly closed container over time) so it is most unlikely that any trace will be left. You could also use the liquid for a first-clean of future paint brushes. The grey residue will probably precipitate out if left for a long time. Be careful that it doesn't stain your chimenea. Dbfirs 17:32, 30 January 2014 (UTC)[reply]

using ENCODE

to find or watch detailed sequences in a given genome (e.g., the human one) - how do I get to them ? It'll be of great help to get assisted here. BentzyCo (talk) 18:03, 30 January 2014 (UTC)[reply]

The article points you at the front door ( http://encodeproject.org/ENCODE/ ) which leads to more specific data with some exploration (e.g. http://encodeproject.org/cgi-bin/hgTracks?db=hg19&position=chr21%3A33031597-33041570 ). Given the systematic, top-down nature of the project I'm a bit surprised at the spottiness of the coverage of certain things at this point, but there's a vast amount of data there nonetheless. To the best of my knowledge, the data still finds its way through to the universal repositories such as http://www.ncbi.nlm.nih.gov/ - see [11] for an overview of some of their capabilities. Wnt (talk) 18:58, 30 January 2014 (UTC)[reply]

Does a colder freezer make ice faster?

Just curious if reducing the temperature of a refrigerator's freezer compartment would make the built-in ice maker produce ice faster? --Navstar (talk) 20:41, 30 January 2014 (UTC)[reply]

Yes, of course. I don't have a specific ref for you. But you might look at latent heat of freezing. The greater the temperature differential, the faster heat flows out, and the sooner you've extracted the latent heat. --Trovatore (talk) 20:44, 30 January 2014 (UTC)[reply]

Oh, wait, you're talking about an icemaker. In that case I don't know. If the icemaker is separate from the freezing compartment to the extent that the temperature in the latter doesn't affect the temperature in the former, then it wouldn't. You'd have to provide the specific design. --Trovatore (talk) 20:46, 30 January 2014 (UTC)[reply]

Be careful! While the obvious answer revolves around the fact that the rate of heat loss is proportional to the difference in temperature (Newton's law of cooling) - which naively appears to prove that a colder freezer would make ice faster - but it's not necessarily correct in this case.

Consider that ice is a much better insulator than water. If you freeze the outer surface of the water quickly, the insulating ice layer will slow down the cooling of the remainder of the liquid. On the other hand, if you chilled the entire body of water down to just a fraction of a degree above freezing, then brought the temperature down below freezing very quickly, then the entire ice cube can freeze almost simultaneously...and quite rapidly. You can probably do even better by 'super-cooling' the water to below zero centigrade and then having it freeze in a fraction of a second!

So the answer isn't an obvious and unambiguous "yes!" - but the precise answer is rather nuanced and may well depend on the kind of material that the ice cube tray is made of - it's volume, shape and thermal conductivity and so forth.

A classic example of how this kind of thing can be highly counter-intuitive is the Mpemba effect - in which (in certain circumstances) it's possible for warm water to freeze faster than cold water! This seems entirely improbable - but it does seem to be true under certain circumstances.

I wouldn't be happy with giving an unambiguous answer to this question!

SteveBaker (talk) 21:24, 30 January 2014 (UTC)[reply]

OK, I see your point. There could be odd nonlinear effects. I'm not so sure I buy the scenario in the second sentence of your second paragraph, though. It's not all (or even mainly) about temperature; most of the heat is the latent heat of fusion. I'm not sure why you wouldn't get the same insulating layer of ice when the already-cold water started to freeze, preventing you from extracting the latent heat from the water on the inside. --Trovatore (talk) 21:34, 30 January 2014 (UTC)[reply]

I've tried to replicate that Mpemba effect a few times. Tried and failed. Not to say it's impossible, but tricky. InedibleHulk (talk) 22:35, January 30, 2014 (UTC)

The simple answer is that the "Mpemba effect" is a pseudoscientific claim with neither factual evidence nor any coherently posited mechanism--per our own article. That said, Newton's a rather well-respected source, and if we're going by anecdote, we replicated his results with statistical significance in high school. μηδείς (talk) 22:38, 30 January 2014 (UTC)[reply]

Aye. I'm still a little partial to it, based on the time I chopped a log into three equal pieces with one swing. The old "something improbable was possible, therefore all improbabilities are probably possible" logic. Doesn't work, but it might. InedibleHulk (talk) 01:08, January 31, 2014 (UTC)

January 31

Valproic acid as a way to a musical talent.

Well, well, well. I've always thought the musical talent, especially the absolute ear, that is the ability to perceive tones as parts of musical scale is genetically driven. You have to be born with it. Encyclopedia Britannica I recall claims there are 3 genes that govern that. Now in the latest Week magazine, which is a short compendium of assorted facts, they published a result of latest study whereas people were given Valproic acid and lo and behold they develop absolute ear. I wonder what the erudite public think about it.

Along the same lines, there has been apparently not an apocryphal story that a Canadian individual sustained a head trauma and after that he found himself with a musical ability that manifested in him learning to play 3 or 4 musical instrument and at the time of the report he was going through the rest of symphony orchestra. How about that? Thanks, --AboutFace 22 (talk) 01:13, 31 January 2014 (UTC)[reply]

The usual term is absolute pitch. The original source for the information you are referring to is http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848041. If you are interested in this topic, the book Musicophilia by Oliver Sacks tells a number of curious stories about the relationship between music and the brain, including gains in ability as a result of brain damage. Looie496 (talk) 05:23, 31 January 2014 (UTC)[reply]

Great question, which raises so many others! The study was small, but the result was impressive - I'll want to see it duplicated. More to the point, I'll want to see if it has benefits in trying to pick up a foreign language as an adult! Also, there are a range of HDAC inhibitors; even ordinary butter (containing esters of butyrate) may be a weak one. I'd like to see if the correlation holds up for all such inhibitors - and if so, why exactly is histone deacetylation tied to memory? That certainly suggests some things having to do with epigenetic markup of specific genes as a means to remember, which can potentially extend even between generations. See [12] And we always thought it was a joke to say that guys think with their balls! All those billions of neurons, yet to imagine that the hidden complexities of one single gamete might conceal a meaningful fraction of the mind. Wnt (talk) 06:09, 31 January 2014 (UTC)[reply]

Nuclear fuel and skin

It would appear from this image that it's best to hold nuclear fuel with tongs or something else to prevent direct skin contact with the fuel. But what if you touch it with your fingers for a few seconds? Surely you wouldn't instantly notice a huge effect; Louis Slotin's encounter with the demon core initially gave him "only" a weird taste in his mouth and a burning sensation in his hand (this is far far smaller, and it's clearly not critical), but I wonder if you might start experiencing some sort of sensation later. I also don't know whether this kind of exposure would be associated with a statistically significant increase in radiation-related illness down the road. Finally, note that I'm definitely not in a position to be touching nuclear fuel, and I wouldn't if I could; it's not a medical advice question :-) Nyttend (talk) 01:51, 31 January 2014 (UTC)[reply]

Unused nuclear fuel gives off mostly alpha radiation, which is almost entirely stopped by your skin. Also, as long as it's for a uranium reactor, it has such a long half-life that it's not particularly radioactive anyway. I imagine the "best practices" might be to avoid touching it, out of an abundance of caution, to keep from dissolving any trace of it in your sweat and somehow getting it inside your body, where it would be slightly more risky, if only as a heavy metal. Or, possibly, the caution is in the other direction (avoid contaminating the pellet somehow, not sure with what).

Now, if it's used nuclear fuel, that's another matter entirely. Then you've got lots of much more radioactive isotopes. --Trovatore (talk) 02:06, 31 January 2014 (UTC)[reply]

Hadn't even thought that the tongs might be there to prevent me from damaging it. Thanks for the explanation re alpha radiation (been way too long since I had classes at all related to this; I didn't even know where to look), and also the pointers on the spent fuel. I was indeed assuming that we were talking about unused fuel pellets, basically because I got the impression from Spent fuel pool and Spent nuclear fuel that the used pellets are left in the rods rather than being taken out by people with tongs. Nyttend (talk) 02:22, 31 January 2014 (UTC)[reply]

RGB colour model

At RGB color model and various other articles, it is mentioned that the RGB model cannot reproduce all colours, but I can't find a clear explanation of why. Any perceived colour can be described by three numbers, measuring the levels of response of the three types of receptor in the eye. Why is it not always possible to reproduce those three numbers by combining the correct quantities of red, green and blue, for some sensibly chosen red, green and blue wavelengths? Three equations in three variables should be solvable? 86.130.66.42 (talk) 02:24, 31 January 2014 (UTC)[reply]

From reading the article, I get the impression that it's saying basically "This color model doesn't explain how we end up with some of the colors, but we've not come up with a better explanation". Beyond that I can't say; I am unable to understand concepts such as chromaticity and color triangles properly. Nyttend (talk) 02:29, 31 January 2014 (UTC)[reply]

The article Imaginary color may be getting at something for you. --Jayron32 02:33, 31 January 2014 (UTC)[reply]

The CIE 1931 color space article explains some of it. Basically, the idea is that absolute monochromatic light runs around the edge of the true color palette, and choosing just three colors from that don't give all the possibilities because you don't have red, blue, and green receptors - you have cones that are maximally sensitive to those frequencies. So a violet color might excite blue less, but green even less proportionally to it than the blue + some red color you would get on a computer screen. The thing I don't get myself, however, is why the RGB color triangle doesn't touch the curve running around the edge of the color space at the frequencies of the emitters. Wnt (talk) 02:53, 31 January 2014 (UTC)[reply]

A large part of the problem is that in the real world, light can be infinitely bright - but in these chromaticity diagrams, there is an absolute white. Another issue is that the frequencies chosen for R, G and B don't perfectly match the peak of the sensitivity curves for the sensors in human eyes - and because people differ in what those frequencies are, the match can never be perfect. Note, for example, that women are much more sensitive to small differences in colors midway between blue and green than men are. The chromaticity diagram (and it's physical incarnation in TV screens and computer monitors) is a compromise. SteveBaker (talk) 03:14, 31 January 2014 (UTC)[reply]

w o w -- I never heard this one before. Looking it up it seems there's something to it. [13] -> [14] [15]. This might have to do with differences in brain development based on androgens, or the fact that women inactivate different copies of color-sensing genes in different cells, at least potentially allowing a weak version of tetrachromatic vision. This seems to have potential consequences for Wikipedia itself. For example, consider a .svg figure in which different levels of infant mortality on a continent are shaded differently. Potentially we could (with some upgrades to the software) allow users to define parameters so that these would be generated on the fly differently, so that women could have a setting to have more levels of mortality labelled than the same figure as viewed by men (and the color blind would have their own options, perhaps grayscale and even fewer levels, etc.) [Of course, I do not mean to imply that these settings should be imposed other than by individual choice of the user!] Wnt (talk) 05:42, 31 January 2014 (UTC)[reply]

RGB system of color representation is a vector system. The problem is that the vectors that constitute the basis are not orthogonal. The origin of the system of basic vectors is located outside of the plane of reference that we see as the color triangle. They intersect the plane of reference at the corners of the triangle. There is no way to express a color outside of the triangle through the basic vectors. Apparently the basic vectors (the coordinate system) were chosen for technical reasons. --AboutFace 22 (talk) 03:31, 31 January 2014 (UTC)[reply]

(OP) I had a later thought. Three equations in three variables should be solvable, but solutions to some cases may require negative amounts of R, G and/or B. Is this the answer? Is it the solutions that require a negative R, G or B that cannot actually be realised in the RGB model? 86.130.66.42 (talk) 03:38, 31 January 2014 (UTC)[reply]

In a word, yes. Treated as an unbounded linear system (a vector space), if any scalar multipliers for a set of basis vectors is permitted, the entire space could be reached. Impose range limitations on those scalars, and effects such as this arise. —Quondum 06:23, 31 January 2014 (UTC)[reply]

Effects of long, long term exposure to radiation on human body/skeleton

Hello dear Wikipedians.

For reasons of fiction, I wish to inquire what might be the effects of 2,000, 5,000 and 10-20,000 years worth of cosmic radiation to a human body. More specifically, a deceased body kept in a glass coffin of sorts, floating idly far away from our solar system. Do I assume correctly that the skeleton does not simply remain, but might alter in certain ways due to the radiation? And what about the rotting process? Anything left as a waste product inside this confined space?

I thank you very much for any educated guesses.

213.104.126.183 (talk) 02:57, 31 January 2014 (UTC)[reply]

A dead body in deep space (which is what I assume you mean by "far away from our solar system") would become very, very cold and freeze solid. At that point, most normal decay processes would essentially stop. If the coffin is not air tight and the body is exposed to vacuum, then volatile compounds (like water) would gradually be lost to space. Dragons flight (talk) 04:53, 31 January 2014 (UTC)[reply]

Cosmic radiation is a little different, but basically you're asking about food irradiation. There's something about meat being irradiated so that you can keep it at room temperature around 70 kGy, which is a lot compared to figures I'm seeing in radiation carcinogenesis in past space missions of 0.12 mGy/day (though to be honest, I didn't look very closely - why bother, if you want you can make your future space shielding better or worse than the missions). So I think you get that in 550 000 000 days, more than a million years? I also didn't look into whether the flavor of heavily irradiated meat is noticeably different, but it should at least look like a corpse. Wnt (talk) 06:21, 31 January 2014 (UTC)[reply]

Unless it happens to drift near a supernova or a pulsar (or, God forbid, a quasar) -- in which case it would be charbroiled before it got to the other side. 67.169.83.209 (talk) 06:39, 31 January 2014 (UTC)[reply]