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October 15

water hands arthritis now

hello

i have recently been alerted to a claim by a fellow piano teacher that washing your hands immediately after playing piano or writing or typing reports or playing parappa the rapper or any other strenuous sort of activity with your hands may eventually result in arthritic symptoms because water erodes rock or something like that

although the rock water weathering thing part i doubt holds any credence is there any scientific basis for these claims? she said she heard it from dr oz some time ago and given his track record and the track records of other talking heads so to speak i would like to know if these claims are true or not thank ~Helicopter Llama~ 00:35, 15 October 2014 (UTC)

Misplaced Pages has an article titled Arthritis which lists different kinds of arthritis. Nowhere does it (or any articles on the specific types of arthritis) list cleaning your hands as a potential cause, even in relation to piano or video game playing. --Jayron32 01:57, 15 October 2014 (UTC)

Water does erode rock over time, but what the heck that has to do with erosion of the joints is beyond me, assuming you actually have flesh covering those joints, and thus the water doesn't drip directly on them. However, Dr Oz does often follow up otherwise sound advice with some such silliness as "If water can do this to the Grand Canyon, imagine what it could do to your joints". The only way I can picture hand-washing actually affecting the joints is if the water is hot or cold, and that warms or cools the finger joints. Of course, if that was the problem, simply changing the temperature of the water would be the obvious solution. StuRat (talk) 02:01, 15 October 2014 (UTC)

Bone is a living matrix with a calcite substrate. It doesn't "erode" except for osteoporosis which is hormonally and nutritionally mediated, see calcium and Vitamin D/ Otherwise, see your general practitioner who will professionally advise you whether this bee ess is bee ess. μηδείς (talk)

Umm, "bone erosions" is the medical term for the bone destruction that occurs in rheumatoid arthritis, see for example Schett G, et al, Bone erosion in rheumatoid arthritis: mechanisms, diagnosis and treatment. Nat Rev Rheumatol. 2012656-64. PMID 23007741. --109.189.65.217 (talk) 19:16, 16 October 2014 (UTC)

That piano teacher sounds like he heard an old wives' tale in the distant past and somehow stuck with it. ←Baseball Bugs carrots→ 08:06, 15 October 2014 (UTC)

The explanation given is certainly nonsense - but that doesn't mean that it's necessarily bad advice. I could imagine that washing your hands cools down the muscles - and perhaps that has a deletrious effect? After all, we use hot and cold treatments to help muscle pain and stiffness and to control inflammation. SteveBaker (talk) 14:32, 15 October 2014 (UTC)

So he might be right for the wrong reason? If so, the next step would be to see what doctors (other than Oz) recommend for easing arthritic pain: hot vs. cold. ←Baseball Bugs carrots→ 14:37, 15 October 2014 (UTC)

To be clear, I'm not saying that this is good advice - I'm merely pointing out that it might be. For sure, erosion of rock by water has absolutely nothing to do with it...but that doesn't mean that the advice doesn't work. It might (for other reasons) be good advice or it might be completely terrible advice. SteveBaker (talk) 05:05, 16 October 2014 (UTC)

I like to point out that Dr. Oz has had the distinction of "winning" two Pigasus_Awards, for his general quackery and "refusal to face reality". See also the description here . This does not mean the man is incapable of making true statements, but to me it means that most things he says should be treated with a healthy dose of skepticism. SemanticMantis (talk) 16:35, 15 October 2014 (UTC)

My family and its obvious genetic traces are legion. But really, I completely fail to see what the problem with "refusal to face reality" is. I checked with my 387 cousins and they're all as mystified as I am. -- Jack of Oz 08:59, 16 October 2014 (UTC)

The thin layer of fat in your skin ought to keep any water on your joints from eroding them. If your joints were vulnerable to water damage because "water erodes rock," then you'd better stock up on scissors... because everyone knows "rock breaks scissors." Of course, you could protect yourself from water-mediated joint damage by covering your joints with paper strips when you wash your hands, because "paper covers rock" (someone stop me... ) loupgarous (talk) 16:28, 17 October 2014 (UTC)

Why do the nuts usually end up on the top of the muesli?

Shaking and stirring the container only mixes the muesli evenly for a while, the nuts seem to be able to "float" to the top. Roger (Dodger67) (talk) 11:38, 15 October 2014 (UTC)

That's a classic question. Please see Granular convection.--Shantavira| 12:08, 15 October 2014 (UTC)

.. aka the Muesli effect (same article). AndrewWTaylor (talk) 12:19, 15 October 2014 (UTC)

LOL @ Muesli effect. You may want to read about Rheology, the "science of the flow of matter" to understand how solid matter can to some degree also "float" aka behave like fluid matter. --Kharon (talk) 12:45, 15 October 2014 (UTC)

Thanks. It's really called the muesli effect.... :)

The nuts will normally be well mixed to start with because the dispenser will have settled into a steady state, shaking and stirring unmixes them. You might also like to look the pictures of circular mounds of stones at frost heavingDmcq (talk) 14:42, 15 October 2014 (UTC)

One interesting counter example is Raisin Bran cereal. They noticed that shipping tended to unsort the mix, and raisins fell to the bottom. So now they add raisins after the box is ~50% full of pure flakes, so that the raisins tend to spread out evenly during shipping. Can't find an online ref, this is described in the book "Why Do Clocks Run Clockwise, and Other Imponderables", by David Feldman. SemanticMantis (talk) 16:30, 15 October 2014 (UTC)

That's clever, thanks for that. Dmcq (talk) 19:37, 15 October 2014 (UTC)

...AKA Brazil nut effect. See here for a nice video demonstration, and links to some relevance for asteroids such as 25143_Itokawa. SemanticMantis (talk) 16:25, 15 October 2014 (UTC)

structural columns

Is the column in this picture supporting any load from the ceiling or building structure. I don't think it is. It looks like its taking no load. The only possible load on it is axial compression just from it being attached to the sides in my opinion. I don't think it's taking any load from the ceiling. Am I correct? http://m.english-heritage.org.uk/about/news/kenwood-house-restored/

The columns at the right hand end in the first photo on that page?

They might just be decorative - but that long pink and white beam might need to be supported in the middle, in which case, they'd be structural. Although the beam isn't under vertical load from structure above it, it does have some weight of it's own - so it's remotely possible that it's really a relatively thin beam that's coated with a bunch of heavy plaster-work decoration. If the beam sagged down a bit, maybe it would bend enough to crack the plaster-work decoration.

I'd guess that the columns are purely decorative though. The beam across them might also be decorative - but if not, it's probably in tension, preventing the walls from moving outwards under the forces from the domed ceiling behind it.

SteveBaker (talk) 14:28, 15 October 2014 (UTC)

I agree with Steve that the beam, if anything, is in tension and if it needed supporting for weight, it most likely would need it from the ceiling so everything is in tension and the weight is transferred to the walls. But the other clues that it's decorative seem to be replication of Greek/Roman Golden rectangle proportions (on edit, our Golden ratio has more. In addition after reading the article on the picture, the original architect Robert Adam returned architecture at the time to the more classical Golden ratio era and developed the Adam style). If the height and width ratio of all the different rectangles created in that room aren't identical, I'd be very surprised (architect should be fired). The height to the beam relative to the width of the room, the height of the columns relative to the space between them, the H/W ratio of windows, bookshelves, etc, are all the same though some are horizontal, some are vertical. Using the proportions in art and architecture are very prevalent and our article sadly lacks more than just the mathematical formulation. Years of watching Donald Duck in Mathmagic Land did not go to waste (though I still can't play billiards). Watch it as it never gets old and will show lots of examples. --DHeyward (talk) 15:24, 15 October 2014 (UTC)

This question was misfiled at the top of the page, so I've moved it down. Wnt (talk) 13:56, 15 October 2014 (UTC)

After use of electricity unused current returns back through neutral wire which

Is not used later,can we reuse that returned electricity of neutral wire again???

Poster was Diwas pandey

Electricity is made up of electrons in a conductor, which move much like water flowing down a hill. But instead of the height above ground, it is the voltage that matters. When electrons return to ground, they are like water that has flowed down the hill. To get energy out of them, you would have to let it flow even further down (to a positively charged electrode) or pump it back up again (with a battery, for example).

It is possible to shock yourself on a ground wire if you disconnect it from the breaker box. This is because a ground wire is not a ground wire if it isn't grounded. You can connect any number of devices one ground wire to the next (in series) - however, the voltage each receives is reduced, which in many cases means they won't work. That is like taking a fast-flowing stream and giving it a long slow way to go downhill instead - it becomes more sluggish. Wnt (talk) 14:03, 15 October 2014 (UTC)

Ideally ground current is zero. There's no reuse as the net flux of current is zero (except for things that charge up). In the U.S. there are single phase 120V/240V and three phase 120/208V systems (there's others but these provide 120V for common outlets). Ideally, the load is balanced across the 240V or 208V terminals which has the effect of reducing current in the neutral wire preferably to zero. The neutral wire only carries the net difference. This is important for a number of reasons including IR drop (which raises neutral voltage above ground) and ground loops. Balancing loads also allows reduced neutral wire sizing and shared neutrals. By code, the neutral wire is only bonded to ground at the service entrance. --DHeyward (talk) 14:59, 15 October 2014 (UTC)

ebola in animals

Can ebola infect a cat? if it can, would the cat show symptoms? By the way i am not asking for advice and i don't have any immediate concern about my health or any cats, but it does alarm me to see ebola in America.

According to the CDC , there is presently no evidence that dogs or cats exposed to Ebola will either become sick or spread the virus. No sick pets have been documented in West Africa or anywhere else. Previous work has indicated that dogs can be affected by Ebola if they have close contact with infected people or animals (e.g. eating corpses), but that the dogs do not seem to develop any apparent symptoms. At present, it is assumed that in the absence of symptoms dogs are unlikely to spread the disease. So dogs and cats are not at high risk as far as we know. However, it may be worth noting that pigs will catch the disease, become symptomatic, and spread it highly effectively . Dragons flight (talk) 15:32, 15 October 2014 (UTC)

There was a case recently with a dog which was indeed euthanized to prevent spread of Ebola; here is a story about how animal rights people collected a third of a million signatures to save the dog. (Gee, I wonder if anyone tried a petition to save the 20,000 Liberians...) Apparently the isolation scheme of leaving the dog with 33 pounds of dog food and a bathtub of water wasn't thought to be good enough. (Feeling glad I'm not a landlord) Wnt (talk) 19:50, 15 October 2014 (UTC)

Yes, Spain destroyed a dog without even attempting to test whether it had Ebola. On the other hand, Dallas has isolated the dog belonging to the sick nurse there and taken steps to provide for its long-term care, with no plans to euthanize it. Dragons flight (talk) 21:25, 15 October 2014 (UTC)

Are they going to simply let it leave isolation once testing shows no signs of Ebola or will they continue to keep it in isolation (perhaps with further testing) until sufficient number of days have passed that they no longer consider it a risk? Nil Einne (talk) 12:23, 16 October 2014 (UTC)

Some searching found which says the dog will be kept in isolation for 21 days and they may not even bother to test it depending on what health authorities suggest and that decomination procedures will be used to dispose of faeces or other material from the dog found in the house. I presume, but it isn't clearly stated, that similar rules will be applied to the dog one isolation. That source also includes pictures of how the dog was taken from the house although the level of caution may be more to do with the house in general that just the dog.

Anyway it seems that the Spanish authorities and Dallas authorities views on this matter aren't actually that different as both seem to consider that the risk from the dog, however low, requires careful management and that testing won't be sufficient to allay concerns. They seem to primarily differ in their views on whether resources should be spent on caring for the dog, and perhaps also on whether it's an acceptable risk to expend that effort (although I'm not so sure on this one, it may be simply the first). It's possible differing views on the rights of the owners (which for better or worse is largely how the human-animal relationship is treated in law) also come in to play . Despite well meaning comments like, it's clearly more complicated than simply differing views on the worth of animal life since both allow the widespread raising and killing of animals for food.

Nil Einne (talk) 13:20, 16 October 2014 (UTC)

Woman having a penis

I understand that a man can have a vagina if he remove or had his penis cut due to cultural or other reasons. But, how does a woman get a penis or is it a man with a penis get a breast transplant or implant? If a man does get a breast implant and doesn't remove his penis and dates a man or marries one, would that make them gay? I am confused on how to understand this transsexual and transgender issue.

See Sex reassignment therapy. Ruslik_Zero 19:25, 15 October 2014 (UTC)

Phalloplasty and Metoidioplasty speak to the surgical processes you inquire about in your first question; in common parlance, these are called "female-to-male" sexual-reassignment surgeries, and a person undergoing these procedures (typically in conjunction with a form of hormone replacement therapy) is known as a trans man, just a person "transitioning" to a female identity is known as a trans woman. A transgendered woman (born male) may choose to undergo hormone therapy alone, they may keep the genitalia they were born with but undergo surgery for breast implants or to create other feminine secondary sexual features, or they may have full sexual reassignment surgery, but in most cases they are likely to identify as female and are said to suffer from gender dysphoria, the condition of perceiving the sex of one's body as differing from the gender that feels natural to them. As to the sexual orientation of two genetic males engaged in an intimate relationship, one of whom identifies as female but has not undergone full sexual reassignment, that's largely a matter of perspective, and opinions vary widely both from those within such relationships and without. Generally, and increasingly, it is considered most tolerant to let those inside such relationships to decide for themselves what the combination of gender identities and physical sexes involved mean about their sexual orientations. It's understandable that some people unfamiliar with these concepts can be confused by the many overlapping and not-always consistent terminology, but the key to understanding the many different perspectives on the matter is to first understand the distinction between sex and gender and to not get too hung-up on nomenclature, whenever the situation allows you to avoid it. Snow talk 08:07, 16 October 2014 (UTC)

Smoke detector placement and orientation

Smoke detectors are commonly mounted on the ceiling, facing downward. But do they actually have to be?

Wouldn't smoke detectors work fine as long as they're facing toward the open air, away from the surface they're against? For example, wouldn't a smoke detector work just as well against the wall, facing sideways away from the wall, or on the floor, facing upwards?

If placed on a bookshelf, does it matter whether the smoke detector is placed on a high shelf or a low shelf, as long as it has open air access?

—SeekingAnswers (reply) 19:53, 15 October 2014 (UTC)

This guide from the National_Fire_Protection_Association says that wall mounting is OK, but they should be within 12" of the ceiling . The reason is fairly simple: smoke rises. Consider a case where there is a small fire on the floor in a corner, and the smoke detector is in the opposite corner. It will trigger sooner if placed near the ceiling, compared to being placed near the floor. SemanticMantis (talk) 20:57, 15 October 2014 (UTC)

And from this instruction sheet for a smoke detector "Smoke, heat and other combustion products rise to the ceiling and spread horizontally. Mounting the detector on the ceiling in the centre of the room places it closest to all points in the room." In a fire a few minutes warning can be the difference between survival and death - go with the manufacturer's recommendations for their product. Richerman (talk) 21:03, 15 October 2014 (UTC)

Near doors in bedrooms is best. ceiling elevation changes are also places where smoke detectors should be placed. In residences, smoke detectors are not really necessary in the center of rooms as fires rarely can develop from any place. Rather, they are placed between points of ignition and people and along their escape routes. Hallways, bedrooms, etc, are where most smoke detectors are placed. usually within 3 feet of a door and within 12 inches of the ceiling. Commercial buildings have them distributed throughout mostly as early warning for Fire Department. --DHeyward (talk) 01:02, 16 October 2014 (UTC)

Why is Germany's power-to-gas so far ahead of the English-speaking world's?

Please compare http://de.wikipedia.org/Power-to-Gas with http://en.wikipedia.org/Power_to_gas

Why is the former so much more well-developed? 76.88.167.15 (talk) 21:16, 15 October 2014 (UTC)

Because Germany is technology world leader in many sections of that field. Like for example Type 212 submarines. Also german automotive and mechanical engineering industry is huge and thus takes a big share in the worldwide struggle to transite traffic and industry away from Petrochemistry. --Kharon (talk) 21:36, 15 October 2014 (UTC)

The OP might be asking about the relative development of the two articles in those two language editions of Misplaced Pages, rather than the relative development of the actual technology in the two countries. Since Misplaced Pages is edited by its readers, the amount of development of specific articles generally depends on the popularity of that particular language edition, as well as how important some particular topic is within the culture of societies that use that language, but is also subject to randomness based on a few editors being particularly interested in some topic. Because the English Misplaced Pages has the most viewers and readers, it also has the most editors, so in general, English Misplaced Pages articles are better developed than corresponding articles in other language editions, such as the German Misplaced Pages, but in this case, it appears that a few German editors care greatly about the topic and so have developed the article more. —SeekingAnswers (reply) 22:37, 15 October 2014 (UTC)

You are free to copy material between the different language editions of Misplaced Pages, however you must acknowlege in the edit summary that is was copied from de: If you do not speak German well, you can use machine translation to assist, but you must tidy the resultant English into grammatically correct prose. CS Miller (talk) 15:33, 16 October 2014 (UTC)

I suspect that it has to do with the reunification of East and West Germany. Many of the East German power plants would have been heavily polluting and poorly maintained, and also perhaps incompatible with West German standards, necessitating scrapping those plants and starting fresh. This is a very expensive process, but does provide the opportunity to incorporate the newest technologies. In most of the English speaking world, the situation was not as dire as East Germany, so the temptation was not to scrap outdated plants, but just keep them going with minor upgrades. However, when all the new German plants near the end of their life cycles, they will be in the same situation, where minor upgrades can keep them limping along, at less cost than total replacements. StuRat (talk) 16:00, 16 October 2014 (UTC)

How to convert an arbitrary monochromatic light (its wavelenght) to a displayable trichromatic light (that is an sRGB screen)?

Is there some linear interpolations formulaes which approximate this conversion (as exact conversion is not possible) while complying with the en:Misplaced Pages:No original research? ... — Preceding unsigned comment added by 77.199.96.124 (talk) 22:41, 15 October 2014 (UTC)

If you read the sRGB article, or any other resource on this topic, you will notice: the outer curved boundary is the monochromatic locus. That means that a wavelength can directly map to the XY colorspace. The formula for this curve is specified by any of several standards; for example, the CIE 1931 standard specifies tristimulus parameters. Then you can use the standard transform to the RGB color space of your choice, i.e. sRGB.

So: if you had pure monochromatic light, you would first compute its corresponding X,Y value by multiplying by the standard tristimulus functions. If you want to over-mathematicalize things, this computation is a weighted integral in which you are premultiplying the stimulus standard function with a dirac delta at the monochromatic light wavelength. In other words, three values are obtained by evaluating the three standard stimulus functions at that wavelength. Next you would multiply that 1x3 matrix by one of the standard 3x3 color space conversion matrices to obtain an "R/G/B" triplet.

Here is some reference code, RGB VALUES FOR VISIBLE WAVELENGTHS by Dan Bruton of Texas A&M / Austin State University Observatory. This code is written in the FORTRAN language, and was the standard model for the MATLAB MuPAD toolbox implementation of RGB::fromWaveLength. His model does not incorporate standard tristimulus functions to approximate human perception; in other words, it is a radiometric, rather than photometric, model.

In actual practice, there's a lot more guess-work and standards-fudging than you might expect! Nimur (talk) 02:35, 16 October 2014 (UTC)

The steps are:

1. Convert from the wavelength to XYZ using color matching functions (as found here, for example) and then to linear sRGB using the matrix multiplication from sRGB#Specification of the transformation.
2. Somehow convert those RGB coordinates into RGB coordinates in the range .
3. Convert that to (nonlinear) sRGB using the formula from the sRGB article.

Steps 1 and 3 are easy. Step 2 is hard because there's no right way to do it. At least one of the three RGB coordinates you get from step 1 will be negative. You can fix that by adding white, i.e. by adding an equal amount to all three coordinates. If you add the minimum amount of white (so that the smallest coordinate is 0.0), then normalize so that the largest coordinate is 1.0, the result will be fine for individual hues, but it will make a weird-looking spectrum with artificial lines and brightness gradients because the amount of white and the normalization factor vary wildly. If you want to display the whole spectrum, you will probably want to add a fixed amount of white across the whole range, and scale by a fixed amount, but this will lead to boringly desaturated colors.

the function that Nimur linked looks very inaccurate and I wouldn't use it if you care about getting the hues right. There's no such thing as a "radiometric" conversion to sRGB. -- BenRG (talk) 17:02, 16 October 2014 (UTC)

Well, BenRG, perhaps you disagree with the utility of that equation; but there does exist such an equation, and it is used by one of the most prominent vendors of image processing software, a package that is used by many researchers across the globe... this specific equation has been published in peer-reviewed journals with applications ranging from color image processing for video compression to hyperspectral imaging research; it has been recognized by the IEEE and the SPIE; it has been adopted by commercial vendors and open-source software...

Presumably, though, you are able to determine that "there's no such thing," and that its accuracy is insufficient for any purpose, so I guess I'll defer to your extensive expertise in the field.

Nimur (talk) 18:37, 16 October 2014 (UTC)

You can look at Bruton's code and at the definition of sRGB and see that the code is wrong. The mathematics isn't very difficult. Most obviously, it puts the RGB primaries (#F00, #0F0, #00F) at 645nm, 510nm, and 440nm, while the correct locations (for sRGB primaries and D65 white point) are roughly 610nm, 550nm, and 465nm, so the hues are actually very far off. The code doesn't claim to be based on sRGB, and in fact predates sRGB (which was published in late 1996), but I don't see how it could be accurate with any red-green-blue primaries. 510nm is more teal than green, and 440nm is violet.

I do see evidence that this function is very widely used, to the point that it's hard to find spectral images that show the correct hues, but this one seems to. This chromaticity diagram is also accurate. (Many other chromaticity diagrams on Commons and the web are incorrectly green at the top, such as this one, but they're otherwise pretty accurate.)

You wrote "His model does not incorporate standard tristimulus functions to approximate human perception; in other words, it is a radiometric, rather than photometric, model." That doesn't make sense, and I think you made it up. That was what I was trying to say, more politely, when I said that there's no such thing as a "radiometric" conversion to sRGB. -- BenRG (talk) 21:25, 16 October 2014 (UTC)

Why not simply use Yxz and let the device apply whatever transforms it needs to display the data containing the brightnesses and chromaticities? Count Iblis (talk) 20:10, 16 October 2014 (UTC)

Old school is to use a rotating color-wheel with area or yime of each color tuned to the sensors sensitivity. Thre lenses, each with a filter did the same thing. --DHeyward (talk) 08:22, 19 October 2014 (UTC)

October 16

Greased sword

There is a sword fight, one person gets slashed in the chest and has a huge gaping wound. What would happen if the sword and the person's chest were oiled and slippery, would the sword cut less? — Preceding unsigned comment added by 88.115.38.169 (talk) 17:16, 16 October 2014 (UTC)

Only maybe if the blow was struck by the side of the sword rather than the edge. For a gross comparison, the oily surface of a cooked bird doesn't seem to stop the carver from getting through it. ←Baseball Bugs carrots→ 17:32, 16 October 2014 (UTC)

I agree, it seems unlikely that it would make any difference whatever unless it was an extremely glancing blow. Do an experiment - get an egg and a knife...whack the egg hard with the sharp edge of the knife...what happens? Cover both with olive oil...do it again. Does it make a difference? No? I didn't think so. SteveBaker (talk) 20:08, 16 October 2014 (UTC)

A greased sword should go through a bit quicker, but not a significant bit. Remember, blood is already slippery. Once the sword's in, it's lubed. In boxing and MMA, they put Vaseline on fighter's faces to prevent friction and tearing, and the same idea would help somewhat against clubs and such, but swords (and elbows) work too finely. InedibleHulk (talk) 13:13, October 17, 2014 (UTC)

How many molecules build the cell? (not types, but in general)

What is the amount of the molecules that the cell made of? 5.28.154.216 (talk) 19:03, 16 October 2014 (UTC)

What type of cell? Crystal cell unit? Bacterial cell? Eukaryote cell? What species if one of the latter two? What tissue? --OuroborosCobra (talk) 19:07, 16 October 2014 (UTC)

It is unlikely that an exact answer can be determined for any specific case; but we can estimate to order of magnitude. We have a few entries in our article on orders of magnitude (numbers), with citations: the human body consists of roughly 10 cells, and 10 atoms. With a little arithmetic, you can estimate an average number of atoms per cell. This leaves the original question unanswered: how many atoms are in each molecule? Well, the answer is very difficult, because there are some molecules (like water) comprised of very small numbers of atoms... water has three atoms. There are other molecules, like DNA, which is commonly treated as a "single molecule," containing millions of nucleotides (potentially hundreds of millions of atoms per molecule). The arithmetic mean value of atoms-per-molecule is not very useful!

So, we probably have a few trillion atoms in a typical human cell (plus or minus a few trillions, or maybe even plus or minus ten trillions or a hundred trillions); and the number of distinct molecules made from that many atoms could be anywhere from a few million to a few hundred trillions. This is somewhat imprecise, but it's not easy to improve the precision without relying on a lot of difficult and tenuous estimations!

Nimur (talk) 19:38, 16 October 2014 (UTC)

Quick answer: twenty billion.

OK - that's going to make people wonder - so I'd better explain how I got there:

It's very hard to generalize - but I think you're probably asking for an extremely approximate answer (which is all you'll ever get!). The smallest known cells (some bacteria) are only 200 nanometers across (there are yet smaller things at 20nm - but there is much debate over whether they are alive...or even exist at all!). The largest cells known are the nerve cells of a giant squid that can be 80 feet long...and the heaviest is an unfertilised ostrich egg. But assuming we're talking about your typical run-of-the-mill human cell, what can we say?

• According to this paper, a "typical" human cell weighs 10 grams.

• This image has the percentage of different molecules in a bacterial cell - it's probably not THAT much different from a human cell - so let's guess that human cells have about the same distribution...that might be a bad guess - but we're only after a very rough answer.
  • DNA is only 1% of the cell by weight - and DNA molecules are huge - so it's not contributing many molecules...so let's ignore it
  • Same thing could be said for the proteins, RNA and other long-chain molecules. They don't make up much of the mass - and they are relatively big molecules.
  • Water is 70% of the mass of the cell - and it's made of very light molecules...so it's going to totally dominate the molecule count.

• So it's probably fair to say that the total number of molecules is pretty close to the number of water molecules - at 70% of the mass of the cell. The other 30% doesn't contain many molecules - because, those are mostly REALLY gigantic molecules!

• The molecular weight of water is 18 - so 18 grams of water is 6x10 molecules (Avagadro's number).
• 70% x (10) x (6x10) / 18 = 23,000,000,000

So: the total number of molecules in a human cell is probably a little more than the number of water molecules, which is around 23,000,000,000 - which we'd better round to 20 billion.

Or a few million...or trillions of quadrillions...depending on what cell you're measuring.

SteveBaker (talk) 20:00, 16 October 2014 (UTC)

October 17

Giving blood to lose weight

If you give blood, will your body burn more fat in response to replace the lost blood? ScienceApe (talk) 02:26, 17 October 2014 (UTC)

Yes, indeed. Replacing a pint consumes about 650 calories. Not much, but every little bit helps. Dominus Vobisdu (talk) 02:30, 17 October 2014 (UTC)

Cody McKenzie recently did that to make weight for a fight. According to a doctor, it's not recommended, but not a terrible idea, in the very short-term. Of course, in that case, it had little to do with burning fat, just that a pint of blood weighs a little over a pound. InedibleHulk (talk) 13:23, October 17, 2014 (UTC)

Right, runners and wrestlers also sometimes also use more conventional excretion (defecation, urination) to reduce weight before a race or a match. BTW, Dominus, your claim makes sense, but do you have a reference for that? SemanticMantis (talk) 14:53, 17 October 2014 (UTC)

In general one should not assume that "uses calories" is the same as "helps you lose weight". For example, in winter, you use more calories just staying alive than in summer, because you need to generate more heat. However, most people gain rather than lose weight in the winter, presumably because they also eat more. Unless both your caloric income and outgo are otherwise rigorously controlled (which is almost never the case) it is very difficult to predit the effect of a single change. --Trovatore (talk) 14:57, 17 October 2014 (UTC)

And don't forget the downside. Giving blood causes you to lose iron, and possibly other nutrients. There is a limit to how quickly your body can absorb iron from your diet, so this imposes a limit on how much blood you can give. (You can also have iron infusions (IV's), but this has it's own negatives.) Also, blood cells can only be rebuilt at a certain rate, even if enough iron is present. And if you happened to suffer an injury and bleed right after having given lots of blood, you might well bleed to death sooner.

The doctor in that McKenzie article says it's about eight weeks for red blood cells to come back. For what it's worth, he looked weak and slow in that fight, though that may have had more to do with fishing instead of training. InedibleHulk (talk) 15:45, October 17, 2014 (UTC)

Something I've thought of, for the morbidly obese, is something like hemodialysis, but where they remove unhealthy nutrients from the blood, like bad fats, bad cholesterol, & excess sodium and sugar, and perhaps increase good fats, good cholesterol, and other needed nutrients. If the person was already on dialysis for kidney failure, this wouldn't pose much additional risk, and could offer quite a benefit, part of which would be losing weight. I think I will ask a Q about this. StuRat (talk) 14:56, 17 October 2014 (UTC)

Effect of oxygen percentage vs. partial pressure on flammability

I have always assumed that the flammability of a give material was a function of the partial pressure of oxygen in the atmosphere it was exposed to and not the strict percentage of oxygen. For instance, I would have thought that a material would be more or less equally flammable in a 21% O₂ 1.0 atm environment as it would be in a 10.5% O₂ 2.0 atm hyperbaric one or a 42% O₂ 0.5 hypobaric one.

But this NASA document, Recommendations for Exploration Spacecraft Internal Atmospheres (Lang, et. al., 2005) says:

By contrast with human respiration that depends primarily on oxygen partial pressure in the atmosphere, materials flammability depends strongly on oxygen concentration (volume percent) and to a lesser extent on total pressure. (pg 11)

but doesn't appear to go any further into the subject.

Where can I learn more about this? I'd like to read about the physics behind this and see some "Constant Flammability Curves" showing pO₂ vs. %O₂ for various materials.

Oxygen#Combustion and other hazards states:

The fire that killed the Apollo 1 crew in a launch pad test spread so rapidly because the capsule was pressurized with pure O₂ but at slightly more than atmospheric pressure, instead of the 1⁄3 normal pressure that would be used in a mission.

which supports my earlier understanding.

thanks fireman stow -- 190.58.249.28 (talk) 04:38, 17 October 2014 (UTC)

Actually, it does not support your previous understanding, it's just consistent with it. In that case, both partial pressure and concentration were much higher than in normal air. I suspect one reason why concentration is important is because all of the gases in the mixture help dissipate the heat. So adding e.g. more nitrogen will make the flame burn, effectively, colder, since there is more gas available to carry away heat from the flame. Chemical reaction are highly dependent on temperature. Also, the oxygen must be able to come into contact with the fuel. If there is more inert filler gas, that may happen less frequently. To use a mechanical analogy, it's a lot harder to get to the buffet if the room is full of people, even if most just stand and talk. --Stephan Schulz (talk) 14:51, 17 October 2014 (UTC)

Yes, "consistent with" is what I should have said. And the Apollo 1 statement is not inconsistent with the NASA document either, as while the latter says that percentage is the stronger effect, it does mention that the partial pressure does have an effect, albeit a lesser one.

Your temperature effect makes a lot of sense to me.

Your crowded room analogy is an interesting one. In a steady state situation where the oxygen is not being consumed, the rate at which a particular type of gas molecule impinges on a unit area is strictly a function of the partial pressure of that species, and fully independent of the partial pressures of other gas species. It might take you longer to get to the buffet, but it will take longer to get away once you are there. But things change when a significant fraction of the local oxygen is consumed and must be replaced. The the additional inert gasses will affect the mean free path and diffusion rate of the oxygen, and thus the rate at which it can feed the fire. Very interesting! I wonder how strong this effect is, and if it might be more pronounced in micro-gravity where convection is not in play.

Thanks, Stephan, for two promising mechanisms. I wonder what their relative strengths are, and I would still love to see some numbers or a graph showing the magnitude of the effect on flammability of pO₂ compared to %O₂. -- 190.58.249.8 (talk) 01:07, 18 October 2014 (UTC)

Dialysis plus

Something I've thought of is something like hemodialysis, but where they remove unhealthy nutrients from the blood, like bad fats, bad cholesterol, & excess sodium and sugar, and perhaps increase good fats, good cholesterol, and other needed nutrients. If the person was already on dialysis for kidney failure, this wouldn't pose much additional risk, and could offer quite a benefit.

So:

1) Is this possible ?

2) Which baddies could be removed ?

3) Is anyone doing it ?

4) Is anyone researching it ?

Thanks, StuRat (talk) 14:56, 17 October 2014 (UTC)

Loyola Medical Center has actually developed a procedure called "LDLapheresis" for patients whose "bad cholesterol" won't respond to diet, exercise, the statin drugs or harsh language. Once every two weeks, a patient spends two to four hours connected to an apheresis unit that removes 70-to-80 percent of the patient's LDL (bad) cholesterol, then returns the blood to the body. The good HDL cholesterol is not removed. here's the Science Daily article loupgarous (talk) 16:37, 17 October 2014 (UTC)

Excellent, but the risk of sepsis might outweigh the benefits, if that's the only baddie they remove and the patient wasn't already on dialysis (although they seem to restrict it to people with extremely high bad cholesterol and/or who have had heart attacks). StuRat (talk) 17:16, 17 October 2014 (UTC)

Plasmapheresis would seem to be one method to remove the baddies:

1) Remove the blood.

2) Separate out the plasma from the cells, by centrifuge.

3) Discard the plasma, which contains most of the baddies.

4) Mix replacement plasma, with the proper level of nutrients, with the cells removed in step 2.

5) Return the remixed blood to the body.

Now I realize there are a lot of risks involved, so this might not be practical for everyone, but perhaps just for current hemodialysis patients. Also, are we able to synthetically manufacture blood plasma, or must we rely on donors ? StuRat (talk)

Blood_plasma#Synthetic_blood_plasma -> Simulated_body_fluid, googling /synthetic plasma/ led me to Blood substitute, as well as . The answer seems to be we can synthesize materials with many properties of plasma, but it's not plasma. /Plasma extender/ and /plasma volume expander/ are other key phrases. SemanticMantis (talk) 18:39, 17 October 2014 (UTC)

• This sounds like an incredibly expensive way to damage red blood cells and waste plasma that could better be used for saving the lives of trauma victims. It reminds me of various world leaders who have tried to extend their lives by consuming the blood of virgins, in one way or another. If, of course, someone like Bill Gates, who has never stolen money from anyone, wants to buy blood to address some hypothetical problem, a laissez-faire system wouldn't stop him. μηδείς (talk) 20:47, 17 October 2014 (UTC)

• Doesn't sound very expensive under my scenario, where they are already in for hemodialysis. It would just be one more machine hooked in. It might even save money, if this method replaces, and is cheaper than, the current methods used to filter out waste products. The current methods also miss some toxins, like one you get from eating star fruit. StuRat (talk) 21:08, 17 October 2014 (UTC)

My understanding is that dialysis costs several (i.e., more than $4) thousand a month. Even insulin treatment costs a tenth of that. I won't argue, we'll simply have to settle for sources on this one. μηδείς (talk) 23:54, 17 October 2014 (UTC)

Yes, dialysis is expensive, but you seem to be ignoring the fact that I've repeatedly said I'm talking about patients who are ALREADY HAVING DIALYSIS for kidney failure. Thus, there would be minimal added cost to doing this in addition to, or perhaps in place of, filtering the blood for waste. In fact, the more expensive it is now, the more opportunity for savings there would be by doing it a new way. StuRat (talk) 00:24, 18 October 2014 (UTC)

Stu, all I can say is I sincerely hope you and no one you know are so bad off as to need dialysis, and if so, ask your doctor. μηδείς (talk) 03:05, 18 October 2014 (UTC)

LOL. I can't believe you're still arguing this when a reference for LDLapheresis was given above. However, since dialysis, like the kidneys, already does filter out bulk fluid including any small molecular weight wastes, this isn't actually a great leap forward, unless you specifically remove particular problems (like LDL) or unless you know all the mid-molecular-weight substances and can re-extract the ones you want from the waste or provide from an external source and then increase your pore size a bit. (Note dialysis implies a choice of pore size, so your argument amounts to an argument over what pore size to use and how then to compensate for problems of dialysis) But aside from targeted, extraordinary interventions against recognized disease states, it's hard to believe any technology we devise soon can outdo a well-evolved kidney in this department. Wnt (talk) 16:06, 18 October 2014 (UTC)

Kidneys seem to do a good job of filtering waste, but don't do such a good job of filtering out trans fats, saturated fat, bad cholesterol, excess sodium, etc. As for excess sugar, the pancreas gets rid of that by producing insulin, but that results in it being transformed from sugar into fat, which isn't a good thing unless you happen to be at risk of starvation or at least underweight. And most of human evolution took place at a time when the current baddies were in such short supply that removing them from the body wasn't much of a concern. StuRat (talk) 16:21, 18 October 2014 (UTC)

Removing just saturated fat or just trans fat or just cholesterol is not really feasible by any sort of dialysis, since they're in the large LDL particles. The sugar can be eliminated with a kidney tweak (SGLT2 inhibitors dapagliflozin and canagliflozin). I'd have to think more about the sodium. Wnt (talk) 19:38, 18 October 2014 (UTC)

Removing saturated fat and trans fats with LDL cholesterol would be good. Also, how about my idea of removing all the plasma, which presumably contains most of the baddies, then replacing it with an artificial plasma ? StuRat (talk) 14:36, 19 October 2014 (UTC)

October 18

How is ebola affected by fppp (fossilized phido plankton powder) or by natural chlorine from onions?

I know that FPPP is used to remove wax that some larger micro-organisms use to move around. If it can be administered topically in a bath, wouldn't this kill ebola? Or do they not use this wax due to their size? Next ; what of natural chlorine from onions or garlic in heavy doses?

thanks mikefromspace on youtube — Preceding unsigned comment added by 71.59.221.4 (talk) 01:43, 18 October 2014 (UTC)

Ebola has a phospholipid coat, so yes, if you rub yourself all over with 'diatomaceous earth' it will probably deal with skin contamination... providing that Ebola viruses have not already entered the body. Likewise, the anti viral properties of onions or garlic will only be effective with topical contamination. The best option is to avoid contact. So if someone in your State has Ebola – move to another continent. Antarctica springs to mind.--Aspro (talk) 02:16, 18 October 2014 (UTC)

Or, if you want real fake ebola medical advice, mail a check for $9.99 payable to No One, care of the wikipedia foundation, and I'll get back to you. μηδείς (talk) 03:03, 18 October 2014 (UTC)

There was a news story last night about some guy who's selling high-dosage Vitamin C as an alleged ebola preventive. It was reiterated there that there is no substance known at present which can either prevent or cure ebola. In short, covering yourself in dirt or taking high dosages of vitamins will have the same effect on ebola as doing nothing. ←Baseball Bugs carrots→ 09:47, 18 October 2014 (UTC)

I agree 100% that these "treatments" will not kill ebola and that they are completely useless. However, there are two caveats:

• "Doing nothing" by providing a convincingly fake treatment can sometimes improve a patients outcome through the placebo effect. But providing an injection of saline or a course of sugar pills would be a better way to do that than all of this nonsense.

• The very reason that ebola became so widespread in this part of Africa when it had been so well contained in previous outbreaks was related to the practice of bathing the bodies of dead ebola victims. The virus is shed into body fluids - and while it can't survive for long (about 2 hours) on a hard, dry surface - it stays virulent for days in moist environments. So if you bathe an ebola patient, you suddenly have not just a little infectious body fluids - but a few gallons of incredibly dangerous bath water to safely dispose of. So bathing an ebola patient in anything whatever is an insanely stupid and dangerous thing to do. So what our OP proposes is not at all like "Doing nothing" - it's more like "What could we think of that would spread the disease MUCH faster?".

So, no. This is a terrible idea. SteveBaker (talk) 13:40, 18 October 2014 (UTC)

I'm skeptical that the placebo effect will do much against an infectious disease. I see it as more useful against diseases with more of a psychological component, say one which causes chronic pain. StuRat (talk) 14:52, 18 October 2014 (UTC)

I don't think the placebo effect works against viruses. ←Baseball Bugs carrots→ 15:17, 18 October 2014 (UTC)

The Tiger Rock Effect totally works. Seriously. It doesn't even need to be a rock. It can be whatever nearby object is usually nearby when virtually everyone on the planet don't have ebola. InedibleHulk (talk) 15:30, October 18, 2014 (UTC)

Can the ebola virus (or viruses in general) be killed by direct immersion in a chemical, such as rubbing alcohol? ←Baseball Bugs carrots→ 14:01, 18 October 2014 (UTC)

Absolutely. Bleach kills it nicely on surfaces, but then bleach can kill almost anything. StuRat (talk) 14:47, 18 October 2014 (UTC)

So theoretically if they want to continue their corpse-cleansing ritual, they could improve their chances to survival by using an appropriate chemical rather than just water. ←Baseball Bugs carrots→ 15:17, 18 October 2014 (UTC)

Yes, but i doubt if they have that much bleach available there, and pouring a toxic chemical on the body isn't exactly part of their tradition. We'd need to change that tradition from "corpse washing" to "corpse disinfecting". StuRat (talk) 15:43, 18 October 2014 (UTC)

AmeriCares cares about one tradition. Clorox to the rescue! InedibleHulk (talk) 16:06, October 18, 2014 (UTC)

As far as using bleach for disinfection, it comes in tablet form too, and that might be a lot easier to ship to Africa in quantity. They could mix it with whatever dirty water they have, to reconstitute it. StuRat (talk) 17:10, 18 October 2014 (UTC)

The One Laptop Per Child project (if funded by the UN) could help. With access to the internet, the African, on the sharp end of this Ebola epidemic would not have to rely on bleach from first world countries. The internet would awaken them (to say for augments sake) if there is a source of Limestone nearby, they can burn it to make quicklime, A very good strident. Anything fermentable can be used to produce alcohol. Another very good strident. Drip the alcohol over wood chips and you get Acetic acid. ] Yes, your getting the drift.. yet again, another very good strident. Collect dead grass twigs and branches, place them in a retort and heat. The liquid that comes out is rich in terpenoids which at the risk of sounding like a broken record: is another very good strident. Africans are not primitive sub humans who are not capable of being masters of their own destiny. If we give them access to our knowhow through internet access, then they can stop being depended on us. They can come up with their on solution and probably react faster. Google's attempts to bring the internet to Africa seem to me better than Bill Gates's simplistic idea to inoculation everybody, only to then have whole families die off due to the lack of basic knowledge of disease prevention which inoculation alone can't prevent. Think if the politician have anything to learn from this Ebola epidemic is that our well being is dependent impart, to others having access the the skill and knowledge base to nip it in the bud before it becomes our problem. For the cost of one single cruse missile, this part of Africa could have been saturated in laptops. How much is the current screening process costing the US and Europe now the Ebola is out of the bag?--Aspro (talk) 20:22, 18 October 2014 (UTC)

A bit of OR but I'd guess that if you eat lots and lots of garlic you might be less likely to be infected. Eating Durian might also be beneficial. People who are infected would be more likely to stay away from you. Dmcq (talk) 15:17, 18 October 2014 (UTC)

Eating lots of garlic might help, as no one would want to come anywhere close to you. ←Baseball Bugs carrots→ 15:19, 18 October 2014 (UTC)

Even if doesn't save you from ebola, garlic has been shown to help keep heart attacks and cancer away. You almost have a better chance of dying from one of those than calling a coin flip. InedibleHulk (talk) 15:34, October 18, 2014 (UTC)

The original idea is extremely unlikely (apart from a slender hope of accidentally decontaminating yourself immediately after exposure). However, the 1960s Soviet technology of using low dose Interferon alfa 2b for influenza (see also Peginterferon alfa-2b) is interesting. As reviewed in the interferon 2-alpha activates JAK/TYK/STAT and p38, whereas Ebola VP24 blocks this pathway. Now if the block is absolute then interferon would be worthless, but if it is a numbers game of chemical equilibrium, or if the cells can be pre-primed with interferon before infection, then maybe it could still matter. It has been suggested that Ebola-like viral particles can provide protection via this mechanism and the question of using interferon has been raised. Now where this gets interesting is that interferons are a) still available for treatment of flu in Russia and other Asian countries ("Grippferon", "Viferon", etc.) and b) set off by myriad environmental circumstances. However, while there are obviously going to be a wide variety of "natural supplements" that claim to increase interferon levels (for example, not recommending: - to summarize, the first is a bunch of herbs, the others sound like eating dirt/leaf litter in a fancy package) I don't actually know what things best stimulate interferons. Nonetheless, garlic apparently does increase interferon alpha level ; I don't see as much about onion though it (like garlic) increases IFN-gamma. Obviously though, these things would have to be eaten if anything other than (maybe) the skin cells themselves are to be protected. Wnt (talk) 15:48, 18 October 2014 (UTC)

12th century Arabic constellation

Hi all.

Can anyone identify the star constellation heading on the left page in this image of the Doha manuscript of the Book of Fixed Stars? A literal translation would do as I can identify the modern constellation from that. It's just that I can't read Arabic script.

I need this information because I would like to nominate the image as a Featured Picture.

Thanks.

Marinka van Dam (talk) 11:40, 18 October 2014 (UTC)

You should ask this question on the Misplaced Pages:Reference desk/Language page - I'm sure they have people who can read Arabic. SteveBaker (talk) 13:28, 18 October 2014 (UTC)

He asked there before he posted here. He's getting some responses there, so I think this one could be closed. ←Baseball Bugs carrots→ 15:15, 18 October 2014 (UTC)

She, actually. Looie496 (talk) 15:33, 18 October 2014 (UTC)

I have no way to know.. Regardless, this could be closed. ←Baseball Bugs carrots→ 15:40, 18 October 2014 (UTC)

Does Marinka look masculine to you? Maybe my question belongs on Language Desk. —Tamfang (talk) 07:03, 19 October 2014 (UTC)

Does the name "Bela" look feminine to you? Two problems: (1) suffix is no guarantee of gender; and (2) Inferred gender ID in a user name is no guarantee of actual gender. It is claimed that a high percentage of Misplaced Pages editors are male, so "he" is my usual default. ←Baseball Bugs carrots→ 16:15, 19 October 2014 (UTC)

Yes, sorry for cross-posting. Wasn't sure which was better. I've had expert response that the left-side page depicts Corona Borealis (The Northern Crown), the right-side page gives the star list for the preceeding constellation Boötes (The Herdsman). Grateful for your time. Marinka van Dam (talk) 17:06, 18 October 2014 (UTC)

October 19

types of the cells

Is it correct to say that the body cells be catalogued according to the tissues? 194.114.146.227 (talk) 00:09, 19 October 2014 (UTC)

See List of distinct cell types in the adult human body. --Jayron32 00:12, 19 October 2014 (UTC)

You can catalog them however you like, but by tissue type certainly seems like an obvious choice. StuRat (talk) 00:13, 19 October 2014 (UTC)

Why Do Sugary Foods Cause Instant Discomfort in Teeth with Cavities?

I have a set of cavities in my back teeth, as soon as I eat sugary foods, they hurt. I understand why sugar causes cavities, I understand how chewing (or irritants, like hot sauce) can cause pain, but I don't see why a piece of candy should cause instant discomfort. My understanding is that bacteria consuming sugar generates acid, but I would assume that that does not happen immediately - and I only experience discomfort in my cavities, not in healthy teeth. --I am not asking for medical advice, the solution is to have the dentist fill them; I'm just curious about what is happening since it doesn't make much sense to me. Thank you for any help:-)Phoenixia1177 (talk) 01:50, 19 October 2014 (UTC)

While we can't give medical advise, there is quite a bit of literature on the internet about this including in our own dentin hypersensitivity article. Dismas| 02:19, 19 October 2014 (UTC)

When I looked for an answer, dentin sensitivity is what I came across, but I don't understand why sugar causes pain (and only in those specific teeth) - sugar isn't an irritant, so I don't understand what it is that causes the pain. If I rub sugar on a cut, it won't hurt, so why should sugar cause pain in that case, what is it actually doing? Thank you for the reply - I definitely don't want advice, I only include my experience because that is how I'm aware of it, I don't imagine anyone can tell me anything besides "see a dentist" anyway. Thank you for assuming good faith, and for your response:-)Phoenixia1177 (talk) 02:34, 19 October 2014 (UTC)

I don't think it's just teeth with cavities. Pecan pie does something like that to my teeth, and they are cavity free. I think it has to do with high-fructose corn syrup, not normal sugar. StuRat (talk) 02:44, 19 October 2014 (UTC)

I believe that high-fructose corn syrup is very much an American thing, much less common in other parts of the world. Sugar sensitivity in teeth is a world wide phenomenon. HiLo48 (talk) 03:02, 19 October 2014 (UTC)

I've read that that can be the case for some people, but in my case, it is only teeth with cavities (I got bored and rubbed various substances on my teeth earlier, one row has cavities, one does not, only the row with cavities hurt from sugary substances).Phoenixia1177 (talk) 02:48, 19 October 2014 (UTC)

This paper seems informative and relevant, but I'm not interested enough to read it thoroughly. I could be wrong. Maybe you'd like to try? Also keep in mind that sugary food contains far more than just sugar. Don't immediately blame the likely suspect. InedibleHulk (talk) 14:20, October 19, 2014 (UTC)

When you have sensitive teeth there are microscopic channels between the tooth surface and the nerve endings. It would appear from our own article and the paper linked above that sugar causes osmotic changes in the channels that are interpreted as pain. And from my own OR you tend to get sensitive teeth as you get older due to wearing away of the enamel and gum recession exposing the more sensitive areas. Toothpaste for sensitive teeth works by temporarily blocking these channels. I just wish someone would come up with a varnish that permanently coats your teeth and cures the problem. Richerman (talk) 14:47, 19 October 2014 (UTC)

It's not permanent, but see dental sealant. Matt Deres (talk) 16:53, 19 October 2014 (UTC)

That seems to be mainly for sealing fissures in the biting surfaces of back teeth. I was thinking of something that you could paint over all the teeth to cure the problem - even if it had to be renewed every so often it would be an improvement, but of course on the front teeth it would have to look ok as well. I'm sure if it was that easy someone would have come up with it by now. Richerman (talk) 17:14, 19 October 2014 (UTC)

I need information about a cross -pollinated fruit named a "brugnon" .

I was told that: 1) it was a cross-pollination between a plum and a peach. 2) This was accomplished by french scientists; hence it's name "brugnon". 3)It has also been called a "White Nectarine". Any information to corroborate or refute this report would be very helpful. Thank you.24.45.51.245 (talk) 02:49, 19 October 2014 (UTC)

Google "brugnon" and some things turn up. The first was this article in the French Misplaced Pages, if that's any help: ←Baseball Bugs carrots→ 03:16, 19 October 2014 (UTC)

Ah-ha! This looks like a job for someone well versed in both French and Botany. Until that person shows up, you'll have to settle for what I've been able to find out.

The short answer is that brugnon is the French word for a kind of nectarine.

OK, longer version: there are lots of varieties of peach (Prunus persica): different coloured skin, different coloured flesh, some with a rough stone and so on. It's like dogs: they come in all shapes and sizes, but they are still the same species.

One group of the varieties of peach are smooth-skinned, without the "peach fuzz".

• In English, a non-fuzzy variety of peach is called a nectarine (Prunus persica var. nucipersica)
• In French, a non-fuzzy variety of peach is called

- a nectarine, if the flesh doesn't strongly adhere to the stone (Prunus persica var. nucipersica again)

- a brugnon, if the flesh does strongly adhere to the stone (Prunus persica var. nucipersica and again)

I got most of that info about it in this article from L'Express (France). In French the title is Pêches, nectarines, brugnons: les confondre c'est pêcher! (Peaches, nectarines, brugnons: the confusion that is peaches !) Google translates this as "Peaches, nectarines, nectarines: confused is fishing!", translating brugnons as "nectarines". The idea that nectarines are the result of a cross between plums and peaches is also addressed in the article: "On dit souvent que les nectarines et les brugnons seraient le fruit d'un croisement entre un prunier et un pêcher. Eh bien non, c'est faux!" (It is sometimes said that nectarines and brugnons were the result of a cross between plums and peaches. Hell no!)

I'll be back to add some pictures after this brief commercial break (ie: once I figure out how the wiki-code for them works.)

Peter in Australia aka --Shirt58 (talk) 08:26, 19 October 2014 (UTC)

Caveat: I have never studied French and I am not a Botanist. But I am a lawyer, and it's our job to know everything about everything. Or at least try and convince people that we do.

Note that the distinction can be made in English by calling them "freestone nectarines" (just "nectarines" in French) and "clingstone nectarines" ("brugnons" in French): . There's also a “semi-freestone nectarine", but I don't know what the French call that. StuRat (talk) 17:19, 19 October 2014 (UTC)

I realise that the two varieties are the result of different hybridisations, but is there a significant difference in flavour. I think I've probably eaten both without appreciating that there was a difference. Does one have a firmer, whiter flesh, or is that just a difference in ripeness? Dbfirs 19:21, 19 October 2014 (UTC)

• See also Nectaplum, Peacotum, Plumcot, Apriplum, Pluot, or Aprium etc. Given the endless varieties of hybridization, and the fact that the names are of often trademarked, deciding whether brugnon is an exact translation of any of these, though, may well be a hopeless exercise. Abecedare (talk) 19:33, 19 October 2014 (UTC)

Are small bodies (<C/2013 A1 size) less likely to be active comets than 1-3 km stuff? How does this vary with distance?

You might think so, a small enough comet would be used up in only one orbit and become an asteroid, while Halley has been spectacular for dozens of orbits. There's a power law with size in the Oort Cloud, though. Much more small comets there. Also, porous comet dirt material is probably a very good insulator. Once all the vaporizable matter is gone, there might be perfectly good ice left inside where the heat can't reach before the surface gets cold again. This would mean that above 2 times the depth of this layer, the amount of comet fuel available isn't width cubed but approaches width squared. Large not tiny comets are more liable to be torn apart if they get close to a major body. I don't know what the sum of all these effects is.

As for the second question, there are few known close to the Sun or between Jupiter Trojans and the Kuiper belt. Comets predominate there (even if not active). How much of this is observation bias? (Venus to Mars asteroids pass close (<.4 AU) to Earth eventually, some very close. Mercury-huggers never would, and share the inferior planet's observation difficulties. A 20,000 years comet only gets recorded close to Earth if it's lucky. The closer a comet is to the Sun, the brighter it is, it brightens more than an inert reflector.)

Can comets be arbitrarily small? Sagittarian Milky Way (talk) 05:35, 19 October 2014 (UTC)

Is all so-called mental illness just anxiety?

Has anyone ever suggested that all diagnoses of mental illness (be it schizophrenia, bipolar disorder, depression, the once popular multiple personality disorder...) are all just anxiety and, in the end, pretty much the same thing? What I'm asking/trying to ask is probably very unclear, so if that's the case, please let me know and I'll try to clarify whatever needs to be clarified. Thanks. --Schweinchen (talk) 13:37, 19 October 2014 (UTC)

This is very roughly what the practitioners of Dianetics claim. I'm unaware of any serious scientist or doctor outside the Church of Scientology accepting that the theory has any validity. Mogism (talk) 13:41, 19 October 2014 (UTC)

Probably been said. But if you compare the official diagnostic criteria, it's not hard to see some differences. You don't need to be delusional to get a depression label, and if you're constantly worried about your self, you're not disassociated from it. InedibleHulk (talk) 13:46, October 19, 2014 (UTC)

There are different syndromes like OCD which causes almost tic-like behaviors, PTSD that might cause night terrors, or schizophrenia which may cause paranoia and delusions. These are quite clearly distinguishable. Different drugs related to things like dopamine and serotonin are used to treat them when possible. Anxiety is more of a symptom that while it can occur on its own General anxiety disorder may also accompany other disorders the way any sense of being out of control might. But just as we wouldn't say that pancreatic cancer and pregnancy are the same thing because they both are often accompanied by diabetes, we wouldn't say all mental illness is just anxiety. μηδείς (talk) 16:44, 19 October 2014 (UTC)

Oddly enough, if you're on pills for anything and these pills cause night terrors, you are ineligible for "night terror disorder". Same goes if the terror is caused by an actual medical condition. If your doctor finds you don't have a medical condition causing it, you do get medicine. You don't even need to take their drugs to feel anxious about drug companies. An awareness is often enough. InedibleHulk (talk) 16:59, October 19, 2014 (UTC)

There are scientists who deny the existence of mental illness, see here:

"But now the DCP has transformed the debate about diagnosis by claiming that it is not only unscientific but unhelpful and unnecessary. "Strange though it may sound, you do not need a diagnosis to treat people with mental health problems," said Dr Lucy Johnstone, a consultant clinical psychologist who helped to draw up the DCP's statement.

"We are not denying that these people are very distressed and in need of help. However, there is no evidence that these experiences are best understood as illnesses with biological causes. On the contrary, there is now overwhelming evidence that people break down as a result of a complex mix of social and psychological circumstances – bereavement and loss, poverty and discrimination, trauma and abuse."" Count Iblis (talk) 18:08, 19 October 2014 (UTC)

DCP=Division of Clinical Psychology the largest division of the British Psychological Society. See also Psychiatry#Mental illness myth Richard-of-Earth (talk) 19:27, 19 October 2014 (UTC)

• Better if the OP asked: is whatever causes anxiety causing all mental disorders? It would be a bit of a Holy Grail of the mental heath field to find a single source for all mental disorders. Sigmund Freud and anyone else who cares to guess at the structure of the mind will say it is a breakdown or inherent dysfunction in the structure that is the basic cause of insanity. I have heard such people referred to as "Structuralists", but of course clear terminology is hard to come by in a field where nobody seems to understand what they are studying. Structuralism (psychology) is a particular theory of consciousness and Personality psychology seems to be the area of study of mind structure independent of neurological structure and more broadly Mentalism (psychology). The more common approach ignores structure (biological, mental or otherwise) and just catalogs behavior, give names to conditions and from past experience (read trial and error) suggest best treatments. This is called behaviorism and it is how the field of medicine has worked in the past. Except in modern medicine medical diagnosis is done with biological tests and not just observation of symptoms. A common complaint I have heard is "I saw the psychiatrist, we talked for 15 minutes, he made a diagnosis and gave me a drug prescription". But to be fair if they find a way to do a biological test for a condition, it is no longer a psychological condition, but a neurological one.

But I suppose you could just sum it all up and say: isn't it all in your mind anyways? Richard-of-Earth (talk) 19:15, 19 October 2014 (UTC)

It's always Coca-Cola, in conjuction with Coca-Cola advertising. InedibleHulk (talk) 19:22, October 19, 2014 (UTC)

Seriously, though. InedibleHulk (talk) 19:28, October 19, 2014 (UTC)

"Offset bandages" ?

1) Do bandages exist with a (presumably plastic) ring built in to offset the bandage from a small wound, to prevent it from sticking to the wound ?

2) If so, what are they called ?

3) Do we have an article on them ? StuRat (talk) 17:01, 19 October 2014 (UTC)

1) They make them for corns and calluses. Here is a site about them. They are made of foam.

2) No special name. Rings or pads.

3) Not that I can find, beyond a passing mention at Callus#Prevention. Richard-of-Earth (talk) 17:20, 19 October 2014 (UTC)

That's a good start, but seems to be self-adhesive foam or felt rings, while I had non-adhesive rings attached to an adhesive bandage in mind. I suppose those rings could be used in conjunction with a bandage, to keep germs off the wound. If they made self-adhesive rings with a piece of fabric covering the top of the opening, that would be even better. StuRat (talk) 18:14, 19 October 2014 (UTC)

Consult your First Aid guide as to whether it's better to aerate a wound or to keep it covered with something. ←Baseball Bugs carrots→ 19:00, 19 October 2014 (UTC)

The method I described should do both. That is, bacteria would be kept out, and yet there would be a small air gap (hopefully antibiotics and the immune system could deal with the tiny amount of bacteria sealed in the air gap). StuRat (talk) 19:58, 19 October 2014 (UTC)

Why don't good bacteria become resistant to antibiotics? — Preceding unsigned comment added by 111.10.167.210 (talk) 19:53, 19 October 2014 (UTC)

Who says they don't? --Stephan Schulz (talk) 20:06, 19 October 2014 (UTC)

Why don't non-oppressed people become resistant to oppressors? They aren't attacked. Same with "good" bacteria. No action, no reaction. Doesn't mean it's impossible to rile them up. But as long as they're with us, they have no reason to go against us. InedibleHulk (talk) 20:29, October 19, 2014 (UTC)

Massive shooting star

I just saw the largest shooting star I've been privileged to witness. It took place around an hour ago in the south of England. Is there a resource or an organisation I can use or talk to in order to determine that I didn't just hallucinate? P.S. This is not a medical question. The Rambling Man (talk) 20:32, 19 October 2014 (UTC)

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