Wikipedia:Reference desk/Archives/Science/2011 December 18

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December 18

Electricity from water

Hi. This 2003 invention is just one of many small-scale electricity generation mechanisms powered by water alone. Compared to water fuel cell claims, most of these seem legitimate. Do we have an article discussing water-powered electricity? Thanks. ~AH1 ^(discuss!) 03:09, 18 December 2011 (UTC)

The article says that pumping water through a gizmo can generate electricity. In no way did it indicate the efficiency of the process. It is by no means "powered by water alone," since energy is required to operate the pump that creates the pressure to force water through the gizmo. The energy output might be far less than the energy input. Edison (talk) 04:13, 18 December 2011 (UTC)

Seems like a turbine except with no moving parts, which I'm sure is a good thing. Is this the only article discussing the technology? If so, I would question whether it's legitimate or not. ScienceApe (talk) 04:52, 18 December 2011 (UTC)

"Do we have an article discussing water-powered electricity?" Yes: Hydroelectricity. Actually, the device described isn't so much generating electricity from water, as from water pressure and flow - like conventional hydro-power systems. While it is interesting, there is no evidence that it is useful... AndyTheGrump (talk) 04:59, 18 December 2011 (UTC)

Our Micro hydro and Pico hydro articles discuss hydroelectric power installations of less than 100 kW and 5 kw respectively, but this U of A invention is at a scale way below what is covered in those articles. Also, the 10 - 16 micron channels of the device would require the filtration of water if used in a "natural" (exposed reservoir) setting, which would impact efficiency. (Note that the physicsworld article linked by the OP doesn't imply any free lunch. Quoting the U of A team, "It allows for the direct conversion of energy of moving liquid to electricity with no moving parts and no pollution.”) -- ToE 06:35, 18 December 2011 (UTC)

"less than 5 kDa by molecular weight"

This is quoted from Wikipedia article Actovegin.

"According to Gulevsky, et al., Actovegin "is highly purified hemodialysate extracted from vealer blood by ultrafiltration."[1] There are less than 5 kDa by molecular weight of organic substances in Actovegin.[4]

"Actovegin has been shown to improve the transport of glucose over a plasma membrane and the uptake of oxygen by tissues.[1] This can lead to aerobic oxidation, which provides a cell with access to more energy and potentially enhances its function.[1] Actovegin has large amounts of superoxide dismutase enzymes and magnesium.[4]"

1) What does it mean to say "There are less than 5 kDa by molecular weight of organic substances in Actovegin."?

2) Does that sentence contradict "Actovegin has large amounts of superoxide dismutase enzymes"? Superoxide dismutase enzymes sound to be organic substances. Thanks, Wanderer57 (talk) 04:37, 18 December 2011 (UTC)

It sounds horribly worded, probably some sort of autotranslation perhaps? (What the heck is "vealer blood"? Do they mean fetal calf serum?). I think what is meant is that that take bovine serum and perform ultrafiltration on it with a 5 kilodalton molecular weight cutoff membrane. Superoxide dismutase is an organic compound, but one that is much greater than 5 kDa. However, reference 6 in the article indicates that Actovegin is protein-free, and injecting proteins like bovine superoxide dismutase into humans is a good way to induce an immune response, so I doubt it has superoxide dismutase in it. You may want to contact User:Tim1965 and ask him to clarify his edit [1] & references. -- 140.142.20.101 (talk) 20:46, 18 December 2011 (UTC)

Apparently "vealer" is a synonym for a young calf; one wonders at the prodigious vocabulary of the Russian scientists who dredged it up for their paper.... - Nunh-huh 00:13, 19 December 2011 (UTC)

Thank you both. I've raised the issue at Talk:Actovegin Wanderer57 (talk) 03:35, 19 December 2011 (UTC)

Quantum measurement problem

Hi, can anyone tell me if there is a particular flaw in the following argument, and if so, what?

Background: Currently, when a quantum measurement takes place, it is not known what exactly causes collapse. It appears from the mathematics that quantum particles exist in superpositions, but we never measure superpositions, only discrete outcomes. The simplest case I can think of is electron spin - typically, it can exist in a hybrid state, of spin-up/spin-down, but we never measure two different spins. (Spin-up and spin-down can be thought of as clockwise and anticlockwise for simplicity.) We do not know whether the electron should be thought of as fundamentally different from the measuring apparatus, or whether it is the same, and some sort of aggregation is responsible for destroying the superposition.

Now: Could the electron in fact be genuinely a spinning particle, and be unaware which way up the universe is? Then the particle itself is on much the same footing as the measuring apparatus - we do not know which way it is spinning (clockwise or anticlockwise about a given axis) and it does not know which way is up. Consequently, the confusion about orientation is reciprocal. That way spin is a genuine property, but it is relative to something. I'm willing to learn the maths needed to understand the issue, but it will take time, and my main interest is in resolving this question, so I want to know what the exact error is (if any) so I can map out the territory I need to cover. I have the Schaum's guide to QM, and have made a tentative start, but no more. Thanks in advance. IBE (talk) 06:13, 18 December 2011 (UTC)

Up and down have no intrinsic meaning. Left on their own the electrons' spin vector would be expected to be randomly oriented in space (all directions, not just up / down). However, an experiment to measure spin works because we introduce a preferred direction, usually by introducing a magnetic field. For example, in the Stern-Gerlach experiment, we pass a beam of electrons (presumably randomized) through the field, we find that half are deflected in the direction of the magnetic field and half are deflected in the opposite direction. Those that follow the field, we call spin up, and the others we call spin down, but the notion of up/down was imposed by our field. The first surprise is that the split is so binary. Classically, we would expect the deflection to be proportional to the z-component of the electron's spin vector, which for randomized classical particles would imply a smooth distribution from up to down. However, the electrons we observe are either completely up or completely down regardless of how random we thought they were originally. The uncertain spin is said to have collapsed into one of the two spin eigenstates. Something about the nature of measurement and quantum mechanics causes this selection process. Since we are discussing measurement, you might also want to think about the double slit experiment where the issue of up/down spin is replaced with a physical separation (i.e. left slit or right slit) which may help to clarify some of the ways that measurement is spooky. For example that experiment shows that individual photons, if not observed, must go through both slits and subsequently interfere with themselves on the other side, which requires a real superposition state (and not merely some hidden notion of left or right). Dragons flight (talk) 08:44, 18 December 2011 (UTC)

I really appreciate the help here, but I already knew most of this. What I mean is that an electron has no concept of orientation, although it knows it is spinning. Up and down, clockwise and anticlockwise, are introduced by the Stern-Gerlach experiment because of the chosen axis, and the uncertainty can happen for both parties. We do not know which way the electron is spinning about it; likewise, if it knew it was about to hit the axis, it would not know in advance which way was up or down. Our confusion about its rotation is reciprocal to its confusion about orientation. Implied is the theory that, just as we ascribe a wavefunction to the electron, it ascribes the same wavefunction to us, so whatever chance we determine of a rotation in a particular direction about any axis, it will arrive at the same chance for the corresponding orientation of the universe, should that axis be chosen. It's the same for the double slit experiment - the particle is not sure which slit goes around it, so the universe's wavefunction is interfering with itself. That sounds preposterous, but it is only a question of lateral shift, not the whole universe going wonky or anything. I'm hoping you or someone else can get back to me on this one. IBE (talk) 16:38, 19 December 2011 (UTC)

I'm not really sure what distinction you are trying to draw in the first part of your discussion. However, I don't think your suggestion that the wavefunction behavior is symmetric from each point of view really makes sense. There would seem to be a number of difficulties. For example, consider the case of an electron stream whose spin direction is prepared to be exactly +X and then is fed into a Stern-Gerlach machine oriented on the Z-axis. It will still report a spin oriented as +/- z after being exposed to the measurement apparatus even though the source electron's were in a well-defined state which (classically) had no z-component. I'm not sure how a situation like that would be understood in your electron's point of view description. In addition, there is a more general criticism. Wavefunction collapse is generally associated with a time-oriented change in something. For example, in the Stern-Gerlach experiment we observe that randomized electrons become up/down spin oriented and retain that orientation until acted upon by further forces. This is a change we can observe. By contrast, from the experimenter's point of view, the Stern-Gerlach apparatus remains the same through-out the experiment. It seems useful to say that the electron wavefunctions are collapsing and the instrument is constant. An alternative description of the universe's wavefunction changing during each measurement would need to account for the fact that each subsequent electron reacts as if it sees the same apparatus. Dragons flight (talk) 09:17, 20 December 2011 (UTC)

I'm not sure if I'm not explaining myself carefully enough, but when referring to the universe's wavefunction, I mean to say that it is from the electron's point of view that the universe has a wavefunction, so each electron in the experiment would ascribe a wavefunction to the universe. If our wavefunction that we ascribe to it (+X in your example) contains information about rotation along each axis, the reciprocal wavefunction contains information about orientation of the universe. Each electron would modify this upon measurement, so each one would independently update its view of the universe. I am imagining it as if the electrons themselves could do theoretical physics. Each one has a textbook handy, and knows the SWE, but each has different information. When particles cross paths, they can exchange information about the orientation of the universe, which is exactly what I think happens with decoherence. I'm not saying it adds anything to our real understanding of what causes decoherence, only that it makes intuitive sense of why it happens so rapidly - any interfering cosmic ray gives some information about orientation, allowing a sort of triangulation. I mean that the wavefunction represents knowledge, rather than absolute existence. I don't know what a particle is in and of itself, but I'm saying that, since spin must be relative to an axis, and the axis depends on the outside universe, you couldn't talk about an electron having a particular wavefunction without that wavefunction having an external frame of reference. On its own, isolated from the universe, I'm saying the electron doesn't even have a z-axis. It needs the Stern-Gerlach experiment (or some interaction with the universe) to give it meaning. But part of my lack of clarity may be my lack of mathematics, so if this doesn't quite make sense, I'll have to read my Schaum's guide some more. IBE (talk) 18:10, 20 December 2011 (UTC)

First, the electron is a fuzzball and not a point. If electrons where point particles then the Pauli exclusion principle would not work. What you take to be a definite measurement is simply the state of the observer mixed in with the apparatus. And since observers are huge critters (and getting more massive every year), the total system is almost exactly "classical". The wave function does not collapse, it just gets so tiny in the scale of everything else going on that it approaches zero uncertainty for the overall system. Hcobb (talk) 18:11, 18 December 2011 (UTC)

i don't know whether this really solves the problem. it sounds to me like you're just saying the same thing from the point of view of the electron-the world is simultaneously up and down. anyway unless there are some predictions your theory can make, it should be cut out by occams razor. — Preceding unsigned comment added by 86.181.92.204 (talk) 22:05, 21 December 2011 (UTC)

Patient-specific tumoral vaccines

Hi, I've been reading about patient-specific tumoral vaccines and they seem great. They harvest the patient's very own tumoral antigens, use them to load a vaccine, add an adjuvant and inject it back into the patient, who develops an immune response to the cancer and destroys it.

However, these vaccines seem to extend life by a few months, but rarely do they achieve complete remission. Why is that? This type of treatment is as targeted as it gets, since it uses tumoral antigens that are specific to the patient's very own tumour. Do these vaccines eventually fail because of problems with the antigens? Is it because the adjuvants used are not powerful enough? Or is it due to some other problem? Thanks!--109.14.102.187 (talk) 09:01, 18 December 2011 (UTC)

The best answer to your questions appears to be "yes". This is a complex topic, as illustrated by the complexity of a recent high-quality review article on the topic of cancer vaccines (PMID 21248270). Major challenges include overcoming tolerance to "self" antigens (as you say, selection and condition of antigen, and of adjuvant, may be key), the potential for autoimmunity, and the stimulation of the most effective T cells while avoiding stimulation of regulatory T cells (PMID 15286781). Clearly, there is much to be learned about the mechanisms underlying these challenges. Scray (talk) 05:28, 19 December 2011 (UTC)

The way I look at it, when somebody gets (a noticeable degree of) cancer, that means something is wrong with their immune system. In the above case it seems to be assumed that the problem with it is an inability to recognize the tumor cells. If so, then that treatment should help, but there may be other problems, like a weak or suppressed immune system overall. Also, any response that puts more pressure on the tumor will cause those cells which have mutated (so they are no longer recognized as tumor cells) to thrive. StuRat (talk) 06:03, 19 December 2011 (UTC)

My impression is that in early-stage cancer it's not that there is something wrong with the immune system, but that the cancer effectively evades it. This is essentially a natural selection problem: large numbers of defective cells are produced in the healthy body every year. The immune system kills them off. If, by chance, an abnormal cell has the ability to evade the immune system, it has a chance to grow and multiply, possibly becoming cancer. Later in the development of a tumor, the immune system is compromised, however. --Srleffler (talk) 18:07, 20 December 2011 (UTC)

There was a good article on cancer vaccines in Scientific American within the last few months. Overall, it shouldn't be too surprising that this is difficult. The tumor cells are not foreign invaders, they are damaged cells from your own body, containing DNA identical to yours, except for the damage. The tumor exists because the cells in it have been selected for evasion of the immune system's defenses against defective cells, among other things. Inducing the body to attack its own tissues is, naturally, difficult and also risky, since once activated the immune system may attack other tissues besides the intended target.--Srleffler (talk) 18:07, 20 December 2011 (UTC)

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Ethanol expiration date

Is there any reason for the expiration date on pharmacy alcohol (used for disinfection etc.)? Gil_mo (talk) 13:07, 18 December 2011 (UTC)

Many products which, by their nature, do not normally decay or degrade (like water or ethanol) are nevertheless given a "best before" date, because the manufacturer knows that the packaging that contains them is imperfect. Sometimes the containers are slightly gas-permeable, sometimes the product is degraded by heat or ultra-violet light, and sometimes there is some small amount of reaction between the container and the product. These expiration periods tend to be quite long, and even then the manufacturer is taking a particularly conservative stance - they're assuming you'll be keeping the product in difficult conditions. -- Finlay McWalterჷTalk 13:19, 18 December 2011 (UTC)

Pepper and salt mills

• http://www.williams-sonoma.com/products/cole-mason-oslo-salt-pepper-mills/

Summary

• Grinds salt and pepper using precision grinding mechanisms.
• Pepper mill has a long-wearing hardened-carbon-steel grinding mechanism.
• Salt mill employs a durable, noncorrosive ceramic grinding mechanism.

Use

• Do not use with rock salt or sea salt flakes.
• Use only black, white or mixed peppercorns in pepper mill; not suitable for green and pink peppercorns.

• In the Wikipedia article: Black_pepper

Green pepper

Green pepper, like black, is made from the unripe drupes. Dried green peppercorns are treated in a way that retains the green color, such as treatment with sulfur dioxide, canning or freeze-drying. Pickled peppercorns, also green, are unripe drupes preserved in brine or vinegar. Fresh, unpreserved green pepper drupes, largely unknown in the West, are used in some Asian cuisines, particularly Thai cuisine.[7] Their flavour has been described as piquant and fresh, with a bright aroma.[8] They decay quickly if not dried or preserved.

Orange pepper and red pepper

Orange pepper or red pepper usually consists of ripe red pepper drupes preserved in brine and vinegar. Ripe red peppercorns can also be dried using the same colour-preserving techniques used to produce green pepper.[9] Pink pepper from Piper nigrum is distinct from the more-common dried "pink peppercorns", which are actually the fruits of a plant from a different family, the Peruvian pepper tree, Schinus molle, or its relative the Brazilian pepper tree, Schinus terebinthifolius.

I am not going to buy them and I am not advertising these products. Rock salt or sea salt flakes are easier to understand. Rock salt can be too large for the grinder and salt flakes may clog it. I just wonder why the "long-wearing hardened-carbon-steel grinding mechanism" cannot take care of green and pink peppercorns? -- Toytoy (talk) 13:55, 18 December 2011 (UTC)

I expect because they have some acidity that would eventually corrode the metal. Looie496 (talk) 17:53, 18 December 2011 (UTC)

I wonder why the pepper mill doesn't employ a durable, noncorrosive ceramic grinding mechanism too. Perhaps the long-wearing hardened-carbon-steel grinding mechanism is cheaper. I have actually seen pepper mills on sale containing mixed kinds of peppercorn including green and pink: ironically, they were made of plastic, and disposable.  Card Zero  (talk) 21:26, 18 December 2011 (UTC)

The plastic disposable ones obviously don't have to be hard wearing, they're designed to be thrown out once they are empty. As well as the ceramic possibly being more expensive, another factor is that it's more brittle. I actually bought a set exactly like this a long time ago, the steel pepper grinder is still going strong while the ceramic one eventually cracked and we had to chuck it out. Vespine (talk) 00:22, 19 December 2011 (UTC)

Dying in an elevator

Why is it mostly impossible to open the door from a stuck elevator from within without tools? Couldn't that kill someone? 88.9.213.105 (talk) 15:06, 18 December 2011 (UTC)

The doors in modern elevators are pretty complex. Remember that when the "elevator door" opens, it's really the synchronization of two doors (the inner cabin door and the outer shaft door) working at the same time. Now presumably you could imagine there being some sort of simple crank mechanism on the inside that would work without reference to the outside, but I'm not sure what purpose that would serve. The possible dangers from abuse of it are probably higher than the odds of actually helping someone. I imagine that you're thinking that the elevator will be trapped between two floors or something, or maybe just a few feet down from a door, and get stuck, and someone will need to get out (maybe they are having a baby or something) and wouldn't it be nice if they could just open the inner and outer doors and squeeze through the gap? But in practice that is a pretty dangerous operation, is really not the sort of judgment call your average person trapped in an elevator should be making, and is also probably not that common. The danger from misuse of such a device probably outweighs any benefits one would get from it. --Mr.98 (talk) 15:23, 18 December 2011 (UTC)

And seeing that there are escape hatches in the top of the elevator anyway... the one way you can leave an elevator and not be killed if the cable suddenly snaps. I've heard of people who are half-in and half-out of a jammed elevator trying to crawl through half an opening as you suggest... when the cable snaps. And thus, they snap. S.G.^(GH) _ping! 17:30, 18 December 2011 (UTC)

The cable doesn't even need to snap. All that's needed is for the elevator to resume normal operations and start moving again, which would snap anyone trying to crawl out. --140.180.15.97 (talk) 19:23, 18 December 2011 (UTC)

Most elevators don't have the escape hatch anymore. At least, not one that you could open without tools. I don't know if it's true, but someone from Otis told me that they stopped because it encouraged heroics and people wound up killing themselves trying to climb the shaft. APL (talk) 23:40, 18 December 2011 (UTC)

Elevators aren't always safe HiLo48 (talk) 00:01, 19 December 2011 (UTC)

There are very few places where being sprayed with lighter fluid and then being set on fire would be safe. APL (talk) 01:53, 19 December 2011 (UTC)

It's fairly coincidental that this question should come up considering there is that news item plus the other woman in New York who died in another elevator incident last week. Dismas|^(talk) 02:54, 19 December 2011 (UTC)

It's worth noting that cable snapping accidents are so rare as to be essentially be discounted entirely when worrying about elevator safety. I think it has happened something like two or three times in the last 100 years and they were very unusual circumstances (planes running into buildings and severing the cables). As our elevator article points out, the most dangerous things regarding elevators involve maintenance malfunctions, or people doing dumb things relating to open doors and/or shafts. Adding a way to manually open the door from within by the common person seems to me like it would increase this sort of risk, not decrease it. --Mr.98 (talk) 02:56, 19 December 2011 (UTC)

And even if a cable snaps, isn't there a safety mechanism to stop it the lift? I once saw some footage of someone demonstrating just that with a model. The cable was cut and the lift got instantly stuck. I assume this is a very simple mechanism that is still used. DirkvdM (talk) 09:06, 19 December 2011 (UTC)

Yes. Elisha Otis himself did a very dramatic demonstration at the 1854 World's Fair. While he was riding one of his elevators he had an assistant cut the cable with a fire axe, a stunt that sold a lot of elevators. APL (talk) 11:23, 19 December 2011 (UTC)

Electromagnetic radiation and their relationship with electro magnetism

I'm trying to get a firm grasp on their exact relationship. So you have light which is electromagnetic radiation. But this light is not affected at all by electromagnetic fields under normal circumstances. Light will not create any electric or magnetic fields in a vacuum correct? Light possesses electric and magnetic fields and that simply causes the wave like nature of light. Is this fairly correct? ScienceApe (talk) 15:39, 18 December 2011 (UTC)

I don't think that Magnetic/Electric fields don't affect them "at all"...--81.17.23.103 (talk) 16:05, 18 December 2011 (UTC)

The normal electromagnetic theory is linear. That means the fields can be added and subtracted and still behave the same way. So that light waves can pass through light waves or fields. Things can get more complicated if you consider matter with non-linear optics or the photon nature such as ultra high energy gamma rays which cannot pass through a magnetic field intact. Graeme Bartlett (talk) 20:45, 18 December 2011 (UTC)

Electromagnetic radiation, including light, fundamentally involves oscillating electric and magnetic fields traveling through space. Equipment designed to measure these fields (provided it is sensitive and fast enough) will detect the passage of this electromagnetic radiation by seeing fluctuating electric and magnetic fields. Visible light is so high frequency that commonly available electrical equipment can't measure the fast fluctuations in the field, but lower frequency radiation such as radio waves are routinely measured with fairly simple electrical equipment (we call them radios). Dragons flight (talk) 20:38, 18 December 2011 (UTC)

I'm not a physics major, but here's my two cents-

• "But this light is not affected at all by electromagnetic fields under normal circumstances" as Graeme pointed out superposition comes into play. If light passes through a place with some standing electric field, It "modulates" (like an AM radio) the standing field. Any sinosodial disturbance in the field will propagate(following maxwell's laws), and tada! there you have light.
• "Light will not create any electric or magnetic fields in a vacuum correct?" As far as I get it this is not correct. There will be an electric field even in a vaccum that is proportional to the (I think to the square) of the intensity. any matter (independant of the type of matter) will experience it. A tightly focussed laser can ionise gasses by this.
• "Light possesses electric and magnetic fields and that simply causes the wave like nature of light" Maybe a better(just clearer)(?) way of looking at this will be changing electric and magnetic fields are light. Their interactions with matter are constrained in certain ways regarding energy and this is causes the particle nature. — Preceding unsigned comment added by Staticd (talk • contribs) 10:18, 20 December 2011 (UTC)

Duality

Can the question of Cartesian Duality be addressed scientifically?--81.17.23.103 (talk) 16:00, 18 December 2011 (UTC)

In principle, yes. If information really flowed into the brain from a nonphysical res cogitans, in principle we would be able to see that happening. But in practice, our current understanding of brain function is far too limited for us to be able to see it. Looie496 (talk) 17:49, 18 December 2011 (UTC)

Not clear at all. The causal effect could be hidden inside quantum indeterminism. --Trovatore (talk) 00:31, 19 December 2011 (UTC)

what does non-physical mean? I never really understood it, I mean I don't deny it but... I also don't understand it...--Irrational number (talk) 17:52, 18 December 2011 (UTC)

Non-physical means interactions that do not obey the currently understood laws of physics or any simple modification of them. Looie496 (talk) 19:26, 18 December 2011 (UTC)

That is a question of metaphysics, it's not easy stuff. I decided to try to learn more about philosophy a couple of years ago and after reading and listening to a lot of material on the subject, it's still mind bending. I suppose the article which addresses this specific subject is Dualism. Vespine (talk) 00:05, 19 December 2011 (UTC)

It would be a complicated question for some versions of dualism, but for Descartes's rather straightforward version it is not so complicated -- he believed in what philosophers call substance dualism. Looie496 (talk) 00:27, 19 December 2011 (UTC)

Help finding source on Chicken vision

I am writing an article on chicken eyeglasses. (yes, chicken eyeglasses see, e.g., [2]). I am looking for a reliable, preferably scientific source, that says that chickens are not color blind, or that that they see in color. I have tried various searches without luck.--Fuhghettaboutit (talk) 16:43, 18 December 2011 (UTC)

This paper shows that chicken colour perception is, as we say in Scotland, pure gallus. -- Finlay McWalterჷTalk 17:00, 18 December 2011 (UTC)

Perfect. Thank you and so fast. If you want to see the silly article it will be at Chicken eyeglasses soon. Damn, damn, damn, damn, damn. It's a blue link. Looks like someone posted after I started writing this in November. Well my version is certainly a four times expansion so I'll be able to make DYK.--Fuhghettaboutit (talk) 17:13, 18 December 2011 (UTC)

Perhaps we need an animal eyewear article, as there's also Doggles and blinders, at least. -- Finlay McWalterჷTalk 17:24, 18 December 2011 (UTC)

I couldn't help but put the search term into Google Patents. I didn't, in my 5 seconds of looking, find the ones described in the article, but I did find this wonderful anti-pecking patent: [3]. Who knew that Kanye West's style was so derivative? --Mr.98 (talk) 17:52, 18 December 2011 (UTC)

The citation for the patent described in the article links to the patent. I uploaded the image from it to the commons a while back. I also found a patent infringement lawsuit between two inventors of chicken blinders; I think one of them is the patent you linked.--Fuhghettaboutit (talk) 18:09, 18 December 2011 (UTC)

Oh yes, I have seen that patent, now that I look at it again. I have an amusing book of wacky patents, and it is featured among them. This of course does not answer your question in any way, shape, or form... --Mr.98 (talk) 03:58, 19 December 2011 (UTC)

Ayds

How much benzocaine was in ayds per serving? --Shanedidona (talk) 18:10, 18 December 2011 (UTC)

5 mg.[4] Red Act (talk) 09:37, 19 December 2011 (UTC)

Thanks --Shanedidona (talk) 19:06, 20 December 2011 (UTC)

Manuka honey health claims - quackery?

I've only been dimly aware of people mentioning that manuka honey (article nearly unintelligible) allegedly has health benefits, both from the eating of the stuff and the smearing of it onto open wounds. Someone mentioned it above and it reminded me. So, is this just another 'miracle health food'/alternative medicine fad malarkey (along similar lines to the Acai berry fad or drinking colloidal silver solution), or is there really something to it? I had a Google around this afternoon but didn't manage to find anything definitive. --Kurt Shaped Box (talk) 20:57, 18 December 2011 (UTC)

Or indeed royal jelly. Remember when lots of people used to swallow capsules of that stuff every day, apparently because it supposedly did or prevented something that I forget now... :) --Kurt Shaped Box (talk) 20:59, 18 December 2011 (UTC)

I consider myself quite "quack aware" but i think there's definitely something to honey. Even a preliminary pubmed search of manuka honey yields some interesting reading. The problem is of course, that the interesting and beneficial effects which have been found get misreported and misrepresented by certain people who promote honey with all sorts of "quacky" claims. Acai berries on the other hand have been found to be no better or worse then most other common berries that can be bought for fractions of the cost of "exotic" Acai berries; it's pretty much ALL marketing, I've seen 1L of Acai berry juice selling for $80! Vespine (talk) 23:53, 18 December 2011 (UTC)

What must people in Brazil think of that? Probably find it quite amusing, in a 'those crazy foreigners with too much money' sense, I'd assume... --Kurt Shaped Box (talk) 09:04, 19 December 2011 (UTC)

Pretty much... except for the locals for whom Acai berries were one of their staple foods, who take an understandably dimmer view on Acai berry prices suddenly becoming so expensive they can barely afford them. Smurrayinchester 09:11, 19 December 2011 (UTC)

Honey in general is known to be antibacterial: honey#In_medicine. Manuka honey apparently is antibacterial, in one particular way, more than other honeys. So it might be a great thing to smear on wounds, but I'm not certain why you'd want to eat it. The pubmed results suggest maybe the idea is to keep your teeth clean, or fight bad breath? I'd be afraid it would kill off your gut flora and give you diarrhoea.  Card Zero  (talk) 06:54, 19 December 2011 (UTC)

Cheers for the answers - I did wonder, as I was expecting to find the typical situation where the sceptics and believers were raining fire upon each other over the internet over whether the stuff worked or not - and detailed entries on the usual debunking websites... but didn't. --Kurt Shaped Box (talk) 09:04, 19 December 2011 (UTC)

You may also be interested in Propolis#Medical_uses. Covers some of the quackery (essentially noted as such), but also gives several references for reputable studies on potential health benefits. SemanticMantis (talk) 13:37, 19 December 2011 (UTC)

Pauli exclusion principle and speed of light

In his televised lecture tonight on BBC, Dr Brian Cox stated that because no two electrons in the universe can have the same energy level (Pauli exclusion principle), then if you change the energy level of an electron here on earth, you must necessarily alter the energy levels of all other electrons in the universe. Fair enough. But he said that this happens instantaneously. How is this consistent with the finite value of c?--92.28.71.33 (talk) 23:36, 18 December 2011 (UTC)

Fixed your link for you. I'm no where near capable of actually understanding or explaining what you're talking about, but my interpretation is that the limit is imposed specifically on "information"; "changes" can occur faster then the speed of light, but those changes can not transmit information. It seems intuitive that if you can cause changes you can transmit information, but that is not the case... At which point I really have to defer to someone who knows what they're talking about. Vespine (talk) 00:00, 19 December 2011 (UTC)

I don't know about this particular claim/interpretation, but for your reading perusal there are other quantum mechanical effects that appear to happen faster than the speed of light (potentially instantly) — see e.g. quantum entanglement. The trick is, as Vespine says, no information is imparted in this fashion, so it doesn't violate special relativity. Einstein called this "spooky action at a distance" because this sort of thing appeared to happen without any obvious physical means transmitting these changes of state. --Mr.98 (talk) 02:51, 19 December 2011 (UTC)

Well, this sounds like nonsense to me. An instantaneous change would be detectable and could be used for faster-than-light communication, so you're right to complain about that, but the rest of it is wrong too. Ionizing an atom doesn't do anything to other atoms on distant planets separated from it by a vacuum, and the exclusion principle doesn't imply that it should. -- BenRG (talk) 07:23, 19 December 2011 (UTC)

I think (haven't seen the show yet) he's talking in terms of wavefunctions here. Every electron's wave function is spread throughout the universe, vanishingly small but not-quite-zero. An electron can be anywhere in the universe... except for in a state already occupied by another electron. Changing the probability of finding an electron in one state must change the probability of finding every other electron in the universe in that same state by an incredibly small degree. Smurrayinchester 09:02, 19 December 2011 (UTC)

I didn't read this before posting my earlier responses. This actually makes sense as a reason for Brian Cox to say what he allegedly said. But it's not true that an electron could become entangled with anything in the universe between measurements. An electron that's seen twice on Earth, a day apart, can't have interacted with anything more than half a light year away in the mean time. And, if this is what he meant, it makes no sense to single out the Pauli exclusion principle as the means of interaction. Any interaction between particles can leave them entangled. Electrons interact electromagnetically too. -- BenRG (talk) 06:01, 21 December 2011 (UTC)

Oops, and like Vespine says, this wouldn't violate the speed of light because it wouldn't transmit information. You can't see a wavefunction directly, you can only infer its shape from the distribution of electrons over thousands or millions of measurements. Because the only place where this change would be relevant would be at the point in space occupied by your electron, you couldn't use this to send information to another planet. Smurrayinchester 09:06, 19 December 2011 (UTC)

I was about to post a "warning beacon" illustration of how one cannot transmit information this way, but I got caught in a quandry. The illustration is that we make a bunch of bound electron (50/50 chance of being measured "up" or "down") pairs, then separate them so that a bunch are on our Alpha Centauri colony and a bunch are on Earth. If Aliens invade AC, the warning beacon is triggered, and Earth has 4 years to prepare its defenses. Earth measures an electron at regular time intervals.

The usual explanation as to why this doesn't work is that if AC collpases their electrons as a warning, getting an up-down pattern like 101110010101..., then Earth measures the exact same pattern because each electron pair is bound and instantly mimics the same up-down state. That's terrific, but Earth has no way of knowing what pattern AC measured to know they were identical - i.e., that the beacon was sent - unless AC actually tells Earth, i.e. by radio, what pattern they measured.

The problem I have now is this. Say we had 1000 electron pairs between the two. Instead of just haphazardly collapsing the electrons on its side as a warning, AC induces a slight magnetic field to make the electron more likely to collapse "up" than "down". Earth measures its beacon in the normal way and finds 700 ups and 300 downs, way more than the 50/50 expected, so it knows that the beacon was triggered. Did I make a mistake here? SamuelRiv (talk) 16:44, 19 December 2011 (UTC)

For the intents and purposes of entanglement, applying the magnetic field measures the state of the electron. Unless, perhaps, you applied identical magnetic fields to both ends of the entangled system, you've broken the entanglement. Smurrayinchester 17:38, 19 December 2011 (UTC)

What about weak measurement? This subject is outside my training in QM (maybe I'll remedy it some day), but it could be used to maintain entanglement. Or does this also have to be done on both sides concurrently? SamuelRiv (talk) 18:02, 19 December 2011 (UTC)

As far as I know, weak measurement is just partial measurement—e.g., when measuring an electron spin, instead of getting an up/down answer (1 bit of information) and leaving the system in an up/down state, you get less than one bit of information and leave the system somewhere between its original state and an up/down state. Weak measurement doesn't circumvent the measurement rules. As I said below, this is unrelated to whatever Brian Cox was talking about (unless the original poster misremembered it). -- BenRG (talk) 21:37, 19 December 2011 (UTC)

Entanglement and the Pauli exclusion principle are different things. Yes, when physicists talk to a popular audience and say "it alters the other one... [dramatic pause] ...instantaneously!" they are normally talking about entanglement. But even in the context of entanglement this is an extremely dubious statement, if not outright wrong, and Brian Cox apparently wasn't talking about entanglement. Original poster, do you know if there's an online version of this broadcast? (And at what time in the video he makes the claim in question?) -- BenRG (talk) 18:15, 19 December 2011 (UTC)

Like I said, intuitively it seems like Q entanglement implies FTL communication, the "warning beacon" above being as decent an example as any, but from the little I understand, it's not as simple as that. I don't really get why but this is a relevant reference No-communication theorem. Vespine (talk) 01:00, 20 December 2011 (UTC)

Well, I'm not sure entanglement's not relevant. As I understand it, the PEP says no two identical fermions can have all quantum numbers the same. That makes sense in the most obvious reading as a statement about pure states of those fermions; that is, eigenstates of the Hamiltonian. But when we're talking about localized electrons, we're not talking about pure states at all, right? At least, not eigenstates of momentum, and I wouldn't think they could be eigenstates of energy either, though I'm having trouble coming up with an exact reason why.

So if we're talking about localized electrons, ones where we have some information about where in the universe they are, then these are some big superposition of non-localized electron wavefunctions spread through the entire universe. Then those are entangled because no two of them can be identical. So if you do something to a localized electron that changes what mixture of all the non-localized electrons it is, then you simultaneously change what mixture of non-localized wavefunctions all the other localized electrons in the universe can be. Does that make any sense? It's not really my field and I also have a touch of a cold, so I may be babbling. --Trovatore (talk) 01:52, 20 December 2011 (UTC)

A pure state is just another name for a unit vector in the Hilbert space. They're called "pure" to distinguish them from mixed states, which are another thing entirely. Where you say pure state you should say position/momentum eigenstate. I see what you mean, though. A wave function that's bounded in position space is unbounded in momentum space, so particles with distinct positions ought to still overlap in momentum. I think that's a valid objection in nonrelativistic QM. But in relativistic QM there is a speed-of-light limit, and if your two particles are far enough apart then they simply don't have time to cross paths.

One could try to argue that all particle positions must be unbounded all the time, because no measurement detects a particle with absolute certainty. But, basically, if you believe that the Earth is really truly in orbit around the Sun, and not somewhere in the vicinity of Betelgeuse, then there's no electron degeneracy interaction between Earth and Betelgeuse. With the quantum mystique stripped off, the claim that "any particle could be anywhere" is just a version of the claim that we can never really know anything. -- BenRG (talk) 06:01, 21 December 2011 (UTC)