Wikipedia:Reference desk/Archives/Science/2010 January 7

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January 7

what does antimatter look like?

Having just watched Angels and Demons, I was curious to know what antimatter would actually look like. In the film, CGI effects are used to show antimatter as a shiny, glittery substance. Is this in any way possible, as common sense suggests to me that it would either be black, colourless or invisible? If we could produce enough to be 'visible', what would we see? Also, could strong magnets as used in the film be used to hold it in place so as not to come into contact with matter? —Preceding unsigned comment added by 86.180.35.161 (talk) 01:21, 7 January 2010 (UTC)

I believe antimatter looks identical to ordinary matter. Appearance is determined by the charged particles in a substance and, apart from having all the signs reversed, the charged particles in antimatter are the same as those in ordinary matter, and changing the signs doesn't make any difference. It is certainly true that magnetic (and electric) fields are used to contain antimatter. See Antimatter#Preservation. --Tango (talk) 01:33, 7 January 2010 (UTC)

So put another way, antihydrogen would look like hydrogen. --Mr.98 (talk) 02:29, 7 January 2010 (UTC)

Antimatter looks identical to matter. And magnets will not affect antimatter any more (or any less) than they affect matter. (Magnets will affect a plasma.) Ariel. (talk) 02:44, 7 January 2010 (UTC)

However, the north pole of a matter magnet will attract the north pole of an antimatter magnet because the charges are opposite. --The High Fin Sperm Whale (Talk • Contribs) 04:34, 7 January 2010 (UTC)

That kind of depends on how you define north and south, but you're right on an atomic level the poles are reversed. But it would have no visible effect at a macro scale (unless someone manages to find a monopole). Ariel. (talk) 05:07, 7 January 2010 (UTC)

The charge carriers (positrons rather than electrons) in any electrical currents would have to flow the opposite way to get current in the same direction and therefore magnetic field in the same direction. For example if you had an electromagnet hooked up to a chemical battery, the antimatter version of that setup would cause the opposite magnetic field compared to the identical normal matter version. You would be able to tell that they were opposites if they were allowed to interact with each other. Rckrone (talk) 20:43, 7 January 2010 (UTC)

I think the point Ariel is trying to make is that the "north" and "south" poles are generally identified based on the macroscopic properties of the field. Hence anyone studying an anti-matter magnet is likely to label its north pole as the one that attracts south magnetic poles in other magnets. Such macroscopic labeling would require that the microscopic structure of an anti-matter magnet be spatially inverted relative to a normal magnet, but the microscopic details are generally invisible and need not affect which end of the magnet gets labeled north or south. Dragons flight (talk) 22:18, 7 January 2010 (UTC)

What about nuclear magnetic resonance? Will a photon that will excite an electron to a 40 kcal/mol orbital excite a positron the same way? John Riemann Soong (talk) 17:29, 9 January 2010 (UTC)

Yes, the same way. Ariel. (talk) 20:52, 10 January 2010 (UTC)

Antimatter in the presence of regular matter would look unusual in that stuff would be annihilating and putting out a huge amount of energy. But if it were contained so that that didn't happen and you were only interacting with it by seeing light reflected off it, it would look like normal matter. Rckrone (talk) 20:51, 7 January 2010 (UTC)

Reminds me of something from, i think, The Feynman Lectures. If you meet an alien who looks just like you and holds out his left hand in greeting—don't shake. He is probably made out of antimatter.—eric 23:32, 7 January 2010 (UTC)

Or your long-lost twin that's in the scouts... --Tango (talk) 02:58, 8 January 2010 (UTC)

Unless you are in a vacuum, that danger is pretty low. Googlemeister (talk) 20:38, 8 January 2010 (UTC)

duphaston tablet

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the talk page discussion (if a link has been provided). --Dragons flight (talk) 05:19, 7 January 2010 (UTC)

Virtual Reality?

will that ever exist?Accdude92 (talk to me!) (sign) 14:32, 7 January 2010 (UTC)

Have you read our article on virtual reality? It exists now. The degree to which SF-style VR will be implemented (and the timetable on which it will be implemented) will vary, naturally. — Lomn 14:41, 7 January 2010 (UTC)

The Holodeck article will be relevant, and it has a section of links to "similar technologies". I find it odd that the virtual reality article seems to be all about goggles and gloves, and I haven't found any article whose topic is the type of virtual reality that was hypothesized as "cyberspace" in Neuromancer. (The cyberspace article is about something else.) There's a Virtual retinal display article which is relevant to the Metaverse from Snow Crash. Comet Tuttle (talk) 18:00, 7 January 2010 (UTC)

It does exist - it's just a matter of degree. For example - in an advanced commercial flight simulator (especially at night) - it's very hard indeed to tell that you aren't "really there" - absolutely everything you can do, see, feel or hear inside an airliner's cockpit during more or less normal flight is simulated with close to perfect fidelity. However, the "free roaming" variety of VR where you're not strapped into a virtual vehicle of some kind imposes some extremely hard technical issues. The "goggles and gloves" issues can mostly be resolved. But the inability to be impeded by obstacles and the inability to walk around freely in the virtual world with the correct amount of inertia being applied to your body are both exceedingly tough problems to crack. SteveBaker (talk) 18:04, 7 January 2010 (UTC)

I would expect the walking anywhere problem but I would have guessed that the brain would have adapted to overlook the lack of inertia part. The brain is good at selectively ignoring part of its inputs. I thought that was part of the explanation of the flight simulator's limited motion appearing so real. 75.41.110.200 (talk) 22:03, 7 January 2010 (UTC)

Steve, I absolutely agree that the inability to be obstructed by objects is a huge problem. Less so on a walking around scale (People don't go around banging their heads against walls to check if they're solid, vision is enough.), but very much so on the "handling things with your hands" level. Some extremely elaborate and scary-looking force-feedback gloves have been invented, but they only solve the "squeezing" part of the problem. The larger part of being able to place your hand through a table is still unsolved, and causes no end of usability issues. APL (talk) 20:21, 8 January 2010 (UTC)

I don't know whether the brain would adapt - but certainly it certainly does not do so quickly. Our learned ability to balance when walking in a circle or stopping suddenly when running gets totally screwed up. I've tried both the "giant hamster ball" and "two-dimensional treadmill" kinds of machine - and they both sucked big time over 10 minutes of use. It just doesn't feel like walking (and in both cases, I was told in no uncertain terms not to even attempt to run!)...when you stop walking - you expect your body to lurch forwards due to inertia - so you unconsciously apply a backwards force to prevent that - but because you were never really moving, all that does is push you backwards. It feels just like walking along inside a bus or a train as it's accelerating or slowing down. Without handles to hold onto, you can't keep your balance. SteveBaker (talk) 23:01, 8 January 2010 (UTC)

I hope so, or I'm out of a job. "Goggles and Gloves" virtual reality absolutely exists. It's very expensive but is often used for military training, Maintenance training for expensive pieces of equipment and other things. Just recently I was at the I/ITSEC conference that had a variety of Virtual Reality systems. Including a very cool system where soldiers were running around a virtual building killing bad guys. (In reality they were running around in a large rectangle of motion tracking cameras.)

On the other hand, if killing bad guys isn't your thing, perhaps you could learn to weld. APL (talk) 20:17, 8 January 2010 (UTC)

I missed I/ITSEC this year (although my software was on show at the Total Immersion stand) - but from what I can see of the footage our guys brought back with them, there is a huge push to do more of this kind of thing. SteveBaker (talk) 23:01, 8 January 2010 (UTC)

Fronts

Why do fronts usher windy weather? How (without using a tv or anything, just by being outside) do you know when a front is on top of you? and why is it not windy when it is over you?Accdude92 (talk to me!) (sign) 18:01, 7 January 2010 (UTC)

As I understand it: A weather front is the boundary between two air masses of different densities. When you have two gases (or liquids) of different densities next to each other and are either moving or pushing each other, you get lots of instabilities (e.g. like Rayleigh–Taylor instability, or Kelvin–Helmholtz instability, or lots of other types), which produce all sorts of turbulence. That's your wind, in part. When you are no longer on the boundary line, you are no longer on that border line that is producing all of those instabilities (winds). As for how you would know if one is on top of you... I'm not sure you can do that without having some knowledge of the weather system as a whole. That is, you'd need to know the air pressure/temperature of a number of different sites, in order to say, "oh, there are two different bodies coming through here." Systemic weather knowledge as a whole generally relies on having more than just local weather information. That being said, some types of fronts are fairly obvious by the weird cloud patterns they produce, like a Derecho. --Mr.98 (talk) 18:25, 7 January 2010 (UTC)

(EC with above). Read Weather front for more information, but to distill it down to the basics, a weather front is the interface between two dissimilar bodies of air, usually a warm airmass meeting a cold airmass in some fashion. When airmasses of two different temperatures colide, several things happen:

• They generate convection currents, as the warm air rises over the cold air, and the cold air sinks below the warm air. The sinking, cold air generates high pressure at the surface (pressing down) and the rising warm air generates low pressure at the surface ("sucking" away). If you have two areas at a different air pressure, the air will move along the ground between the two of them, from the high towards the low, in an attempt to equalize the pressure. Hence "wind".
• Warm air has a higher dew point than cold air does; thus it has a higher "carrying capacity" with regards to water vapor. Just like when you breath hot breath on a cold glass, and you get little water droplets, when the hot moist air meets the cold, dry air, lots of little water drops form. Hence "clouds" and "rain"

These two effects happen any time you have warm and cold air meeting. The difference between a "warm front" and "cold front" and "stationary front" comes down to which air mass is doing the "pushing" and which airmass is being "pushed". If the warm is moving into the cold, it's a "warm front". If the cold moves into the warm, its a "cold front". Some more reading along these lines can be found at Surface weather analysis and, depending on how advanced you want to get, Synoptic scale meteorology. --Jayron32 18:29, 7 January 2010 (UTC)

There are several things you can look for that will tell you a front is passing you

• The Pressure drops and then rises again
• The wind shifts direction
• The wind becomes gusty and then turns calmer again
• The temperature changes
• Humidity changes
• Usually there is some precipitation

Dauto (talk) 19:19, 7 January 2010 (UTC)

The barometer was once the most important weather diagnostic and predictive tool, because it detected pressure changes associated with incident fronts and changing airmasses. In today's technological world of interconnected weather stations, NEXRAD doppler RADAR, and GOES weather satellites, we have other ways to predict and map weather changes and front systems; but you can still do a pretty good job predicting short-term weather with nothing but a barometer. Nimur (talk) 21:42, 7 January 2010 (UTC)

Look out your window. If you live in the plains you will often have a good long view of the approaching clouds associated with the front. 75.41.110.200 (talk) 22:00, 7 January 2010 (UTC)

A major process for why fronts cause precipitation is adiabatic cooling. Whether you have a warm front or a cold front, you basically get warm air rising over the cold air (no matter which air mass is stationary). If the warm air has a lot of moisture (especially on a hot summer day), that air has a LOT of energy. Think about it -- evaporation is an endothermic process. As that warm air rises, the pressure drops, the solubility of water in air falls, and the water condenses -- condensation is an exothermic process. But that makes the air parcel warmer than the surrounding air, and causes it to rise, and lose more water, which encourages it to be warmer than the surrounding air, so it rises, and loses more water ... wheee, positive feedback. When that air parcel eventually comes back down (often due to convection currents), the air mass will be much hotter and dryer than it started out. (This hot dry air might in turn encourage more evaporation at the surface....ooh look this strengthens the storm system and sustains the driving force for the accumulation of giant winds and big stormclouds! Wheeeee)

Another major thing that happens at fronts are convection currents. Different air masses at different temperatures will have differing pressures and densities. The cold air will be denser ... but that means its geopotential height for any given pressure will be shorter. The effect is that you get a high pressure area at the surface but a relative low pressure area in the upper atmosphere. So air flows from the cold air to the warm air at the surface, but from warm air to cold air in the upper atmosphere (e.g. at 500mb or 300 mb pressure). Think a big lake breeze (see the diagrams at sea breeze -- the thermodynamic forces at play are similar, just on a much larger scale). Now toss in concepts like the Earth rotating and other dynamics and you get sustained storm systems... John Riemann Soong (talk) 17:45, 9 January 2010 (UTC)

Think of fronts as the collision of two air masses: warm and cold, moist and dry. At the actual front, the warm air masses rise and the cold air mass sinks, creating an imbalance of temperatures, cloud formation, and wind. Also, sometimes instabilities within fronts may be enough for a section of the front to undergo cyclogenesis, as we have seen this winter. Since fronts are associated with low pressure systems, you have lower-level convergence of air masses that are separated by fronts. ~AH1^(TCU) 20:16, 9 January 2010 (UTC)

How do I change my ocular dominance?

Subject. HitmanNumber86 (talk) 18:04, 7 January 2010 (UTC)

Answer: Training. --Jayron32 18:18, 7 January 2010 (UTC)

Are there exercises I can do, or chemicals I can use? By the way, cite your sources, please. —Preceding unsigned comment added by HitmanNumber86 (talk • contribs) 18:27, 7 January 2010 (UTC)

Wear an eyepatch? 78.151.131.82 (talk) 20:50, 7 January 2010 (UTC)

Poke out your dominant eye? I'm not an expert but I'd say it's not possible to change it, unless maybe you are younger then 5. The visual cortex is one of the best studied areas of the brain so there probably is a good answer somewhere. I don't think the eye patch will work either. One thing I heard recently is that when a baby is discovered to have a lazy eye (Amblyopia), they put a patch on the strong eye. Unsurprisingly the weak eye's development gets strengthened and after some time it can be made to catch up and become pretty much "normal". However, surprisingly, to me at least, patching the strong eye does NOT weaken its development, even if the patch is worn for extended periods, like months, during early development. Vespine (talk) 21:18, 7 January 2010 (UTC)

This actually falls into the category of medical advice (intentionally or not), and we shouldn't be giving answers. Looie496 (talk) 21:40, 7 January 2010 (UTC)

I disagree. I wouldn't consider not liking your eye dominance to be a medical condition. --Tango (talk) 22:40, 7 January 2010 (UTC)

I wonder whether this might be similar to changing your hand dominess or Handedness which may be possible, but is problematic [1]. If you believe the " Consulting and Information Center for Left-handers and Converted Left-handers" extremely so [2] Nil Einne (talk) 00:25, 8 January 2010 (UTC)

Large Hadron Collider question

I just read some of Eric Johnson's document, The Black Hole Case: The Injunction Against the End of the World, and it is quite an insightful text, but I'm left wondering, if this machine is deemed unsafe somehow or another, who's got the power to shut it down? –Juliancolton | ^Talk 19:35, 7 January 2010 (UTC)

The chances of that happening is somewhere between zip and nill. Dauto (talk) 20:25, 7 January 2010 (UTC)

Still, the question of jurisdiction is an interesting one. --Mr.98 (talk) 23:11, 7 January 2010 (UTC)

Since the Large Hadron Collider is astride the French-Swiss border, part is within the jurisdiction of France and part within Switzerland, so I'm going to say "the authorities" in either country. Comet Tuttle (talk) 20:29, 7 January 2010 (UTC)

The CERN article says "As an international facility, the CERN sites are officially under neither Swiss nor French jurisdiction". It doesn't really explain what is the pertinent jurisdiction both for spectacular-death-by-physics matters, but also more humdrum stuff like office punchups and accidents in the workplace. -- Finlay McWalter • Talk 20:44, 7 January 2010 (UTC)

Thanks all. –Juliancolton | ^Talk 20:55, 7 January 2010 (UTC)

Here is a relevant quote from 2007, regarding the protocols that make CERN exist, by the CERN legal council:

The Protocol also grants us [CERN] immunity from jurisdiction of the national courts, to ensure our independence from individual Member States. Mind you, this doesn't mean we operate in some kind of legal vacuum: the Protocol requires that CERN settle its disputes by other means. This is why claims by the members of our personnel against the Organization should be submitted to the Administrative Tribunal of the International Labour Organization, and why conflicts between CERN and its contractors are decided not by the national courts but by independent experts appointed by the disputing parties.

...which seems like quite a legal tangle. --Mr.98 (talk) 23:11, 7 January 2010 (UTC)

At a political level, rather than a judicial one, I assume the member states have the authority to withdraw their financial support which would effectively shut it down. I imagine one could also play some legal chicanery such as the host nations asserting jurisdiction over the power lines that feed the site even if they don't have jurisdiction over the site itself. But to the legal question of what external party has the authority to order a work stoppage? I think the answer might be none. Dragons flight (talk) 23:26, 7 January 2010 (UTC)

Nice find, Mr.98. Since they have been set up as accountable to nobody, they are a sovereign; so I think the way to settle this matter is going to have to be an invasion by force, though of course the scientists have a supercollider as the main weapon on their side. Comet Tuttle (talk) 23:47, 7 January 2010 (UTC)

Actually Mr.98's note about lack of jurisdiction is already mentioned in the PDF that the OP cited in the first place. Comet Tuttle (talk) 23:52, 7 January 2010 (UTC)

Yes, looking at it closer, it goes over the jurisdictional issues pretty clearly. Page 49 of the PDF. --Mr.98 (talk) 00:07, 8 January 2010 (UTC)

I presume if another country is convinced it would destroy the world, they would also consider they are entilted to destroy it if diplomatic efforts fail. This technically means any soveign country but it seems likely only those who have a resonably chance of attacking and destroying it like the US, China, Russia, probably India and perhaps Pakistan, Israel and Japan (if they decide to remove their inability to launch a war and perhaps develop nuclear weapon) should be considered. Do note I've purposely excluded those from the EU who likely have an ability to shut it down without resorting to war. Presuming they are accurate in their belief, it seems likely such an attack would be considered justified under international law although this may not be enough to stop a counter attack. In reality, it seems rather unlikely any country would have to resort to such actions although the threat of war may or not be a useful part of their response Nil Einne (talk) 00:34, 8 January 2010 (UTC)

Did you say unlikely? I think that's an understatement. As I said above the chances are somewhere between zip and nill. Dauto (talk) 01:28, 8 January 2010 (UTC)

I think Nil Einne meaned it is unlikely a country would have to take military action in order to stop the LHC (because there are better ways to do it), not that it is unlikely the LHC needs to be stopped (which is, indeed, an understatement). --Tango (talk) 03:01, 8 January 2010 (UTC)

Well I think the chance a country will need to take military action even if it is necessary to stop the LHC is probably close to zip and nill too (it's not as if we're talking about North Korea here) which may have been what Dauto was saying. However it does illustrate a point. These countries by having the ability to take military action do have the power to shut it down since however they do it, they will be able to shut it down if they really feel it's necessary Nil Einne (talk) 05:07, 8 January 2010 (UTC)

Plastic bowl used in microwave

A nervous friend placed an old plastic bowl in a microwave and heated food.

When removed, the bowl was found to be entirely unaffected. Nonetheless, it was thrown away as a precaution.

She's worried that the bowl may have released harmful fumes that could continue to be dangerous in the future. Assuming the microwave is carefully wiped out, is there really any ongoing danger from future cooking? --Dweller (talk) 20:02, 7 January 2010 (UTC)

Your friend may have heard about the potential long term risk (a pretty low risk) of using plastics with certain carcinogenic plasticisers in contact with food. For this reason it's a good idea to use either pyrex or microwave safe cookware in the microwave. But the "danger" associated with a single use is negligible (and entirely taken by whomever ate the food) and there's no deadly cloud of killer gas lurking anywhere. If your friend had set the plastic bowl on fire and sat in the room while it burned down, that'd maybe carry the risk of smoking a few cigarettes. So no. -- Finlay McWalter • Talk 20:26, 7 January 2010 (UTC)

Could a knowledgeable editor add a discussion about this to our article section Microwave oven#Hazards? I hear a lot about this sort of concern — specifically, that molecules of some sort of biologically harmful plastic will leach into the food — but the only mention in our article is a concern that the plastic will melt. Comet Tuttle (talk) 20:43, 7 January 2010 (UTC)

Let me supply a link, instead of just jabbering: a Harvard Medical School article that discusses "microwave-safe" containers, and advises us against microwaving plastic wrap, water bottles, and several other plastic containers, because of concern about leaching the plastic into the food. Comet Tuttle (talk) 20:50, 7 January 2010 (UTC)

See Bisphenol A for a related plastic compound that is hazardous to health. ~AH1^(TCU) 20:08, 9 January 2010 (UTC)

Aqua Amino: "An energised vortex implosion" | Clean up your amino acid loading bays | Restore water to its original crystal structure

Today I bought this bottle of water at a leading chain-store here in South Africa, but I'm highly suspicious of quackery here, so much so that I think our regulatory bodies should maybe take this product down. It's called "Aqua Amino" [3] and appears as a bottle of mineral water, but on the bottle it makes several extremely interesting claims:

• How the process works:

Your DNA provides "loading bays" in your cells where nutrition is 'offloaded' to feed the cell.
The problem is, these loading bays get clogged up until they simply shut down.
Aqua Amino works at DNA level thereby providing your DNA with an optimal blue print to clean up your amino acid loading bays and enable effective amino acid delivery.

The result is a vast improvement to your daily health and renewed levels of vitality.
By allowing your nutrition system to be more efficient, your natural immune system operates at a higher level, providing near-perfect defense against impurities, viruses and bacteria.

• Before and After photo of the water

Aqua Amino is bottled at source in the Magaliesberg Mountains. Its purity is absolute but what sets it apart from other mineral waters is the gara system, a molecular mechanism that creates an energised vortex implosion. This implosion restores water to its original crystal structure, creating 'forgotten water'. The difference is clear, as shown in these pictuers that were taken at the E.F. Braun Wasserkristalle laboratory in Switzerland.

Does any of this sound legit? Rfwoolf (talk) 21:24, 7 January 2010 (UTC)

Not a drop of it. -- Finlay McWalter • Talk 21:29, 7 January 2010 (UTC)

Amazing stuff. Cuddlyable3 (talk) 21:47, 7 January 2010 (UTC)

Sounds like they're on about water memory, sorta. -- Finlay McWalter • Talk 22:04, 7 January 2010 (UTC)

To expand: water isn't a crystal, if you couldn't metabolise amino acids you'd die, if you drank something and it could interact with your (carefully husbanded) DNA you'd die, drinking water won't vastly improve your health unless you're dying of thirst, your immune system isn't materially helped by drinking anything (bar fixing obvious clinically-significant deficiencies), and drinking water won't give you "near-perfect defense" against anything. And this stuff is somehow "pure" yet also contains this impossible nanotechnological wonderstuff. -- Finlay McWalter • Talk 21:55, 7 January 2010 (UTC)

I can't find anything about a "gara treatment", so it's likely that they made it up on the spot. However, searching for "energized vortex implosion" returns this and several other quack products, leading me to belive that "vortex" and "implosion" are pretty common pseudoscientific words, that may have some specific meaning. (anyone who knows more care to elaborate?). The site linked above does reference what is undeniebly water memory. This is decidedly NOT spam. You should not by any of these products, from this or any other site. Buddy431 (talk) 22:32, 7 January 2010 (UTC)

Of those claims, only two are even potentially correct:

1. Aqua Amino is bottled at source in the Magaliesberg Mountains.
2. these pictures...were taken at the E.F. Braun Wasserkristalle laboratory in Switzerland.

Everything else is clear nonsense. (And the ice pictures don't demonstrate anything; they're just pictures of different-sized ice crystals.) TenOfAllTrades(talk) 22:37, 7 January 2010 (UTC)

E.F.Braun appears simply to be someone who takes rather nice microphotographs of ice crystals - http://www.wasserkristall.ch/ -- Finlay McWalter • Talk 22:41, 7 January 2010 (UTC)

I remember seeing a product with concentrated distilled water in it. Ariel. (talk) 23:13, 7 January 2010 (UTC)

I'm darned if I know what this paper is using? -- Finlay McWalter • Talk 23:17, 7 January 2010 (UTC)

Similar pseudoscience to Penta Water. Fences&Windows 23:55, 7 January 2010 (UTC)

Crystal water at room temperature? sounds like Ice-nine to me :) Dmcq (talk) 10:44, 8 January 2010 (UTC)

If I could make water that "worked at a DNA level" providing the DNA with "new blueprints" I would be a super-villain. APL (talk) 02:52, 9 January 2010 (UTC)

There are, however, many different phases of ice and crystal structures in water. Thesetwo articles may be of interest. ~AH1^(TCU) 20:05, 9 January 2010 (UTC)

Why do cold fingers get pruney?

I notice that when it's very cold outside, my hands look as if I've taken a very long bath. Why do fingers get pruney skin from cold exposure? --70.167.58.6 (talk) 23:09, 7 January 2010 (UTC)

There is a myth that pruney fingers after a bath is due to water being absorbed into the skin. This is not so, see: Wrinkle_(skin)#Pruney_fingers. So maybe cold is causing the same reaction in your fingers. Ariel. (talk) 23:29, 7 January 2010 (UTC)

That section talks about vasoconstriction, which does, indeed, happen in the cold, so that makes sense. --Tango (talk) 01:23, 8 January 2010 (UTC)

in vitro use of enzymes

I'm trying to see whether I can use tyrosine hydroxylase in vitro. I've looked up some of the literature and apparently I need to activate it with phosphorylating agents like various MAP proteins -- but apparently they're talking about E. coli transfection, and not like, running your enzyme on reflux in a test tube or something? John Riemann Soong (talk) 23:49, 7 January 2010 (UTC)