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December 6

Vacuoles, vacuolation, vacuolisation and vacuolization

Is vacuolation the same as vacuolization? As it stands, the former currently redirects to a section in the article for vacuoles in which it states that this is a process in which vacuoles form pathologically, while the latter is its own article that might seem to indicate pathosis but doesn't necessarily spell it out nicely. Vacuolisation, which appears to me to be nothing more than a (perhaps British) spelling variant of vacuolization, redirects to the main article on vacuoles. This is what I think -- correct me if I'm wrong:

Vacuolisation and vacuolization are spelling variants of the same thing
Vacuolation and the aforementiones spelling variants are variant words of the same thing -- sort of like dilation and dilitation.
The mini-section on this concept within the article on vacuoles should make a statement or two about it and include a link to the article that will delve into it deeper.

Let me know if there's any disagreement on the definitions, etc. before I go ahead and do it. Thanx! DRosenbach ^{(Talk | Contribs)} 00:47, 6 December 2009 (UTC)[reply]

It may be best if this discussion happened on the talk page of the articles in question (pick one to have the discussion, and leave notices on the other talk pages). Since this involves a question which stands to have a material impact on the content of the article space, the discussion should probably happen on those talk pages, since editors who edit and patrol those articles would likely be interested in it. --Jayron32 01:04, 6 December 2009 (UTC)[reply]

I didn't imagine that the talk pages of any of these articles were nearly as high-volume as this page. Additionally, the editors of the aforementioned articles obviously have left this crucial point unmanaged for some time. DRosenbach ^{(Talk | Contribs)} 02:12, 6 December 2009 (UTC)[reply]

OK -- I placed notes on both the article talks to see here. Now we can discuss it here. DRosenbach ^{(Talk | Contribs)} 02:15, 6 December 2009 (UTC)[reply]

Wouldn't WikiProject Biology be the place to discuss such article issues? Fences&Windows 16:13, 6 December 2009 (UTC)[reply]

I agree with Fences - discussion of article content belongs in article Talk space, where it will be archived along with the article, or in a linked wikiproject created for such a purpose. -- Scray (talk) 18:08, 6 December 2009 (UTC)[reply]

Why does increasing CO2 concentration matter?

Doesn't 350 ppm CO2 absorb the same amount of infrared from the miles of Earth's atmosphere as 400 ppm? I can see how the difference between 350 and 400 ppm CO2 in air would change how much infrared could be absorbed by a test tube's width, but for the vast depth of Earth's atmosphere, I just can't understand how it could change the total absorption. Are there any articles or sources that discuss this? I've looked at greenhouse gas, global warming, radiative forcing, and their talk pages, but maybe I overlooked something? 99.56.139.149 (talk) 01:13, 6 December 2009 (UTC)[reply]

350 to 400 ppm represents an increase of 14.2%, so all other things being equal, this will increase the "greenhouse effect" contributed by the CO2 by 14.2%, which is a significant and measurable amount. Regardless of the size of the sample, a 14.2% increase is a 14.2% increase. --Jayron32 01:25, 6 December 2009 (UTC)[reply]

Unfortunately not, Jayron - changing the concentration at the bottom of the atmosphere by 14% does not increase the total absorption by 14%. See optical depth for the physical mechanism of increased gas concentration on total atmospheric absorption. For gas of uniform density, optical depth is exponentially related to concentration. Compound this by the fact that the atmospheric profile is also roughly exponentially decaying with altitude. Nimur (talk) 02:23, 6 December 2009 (UTC) [reply]

Also keep in mind that greenhouse effect is only one effect. Atmospheric chemistry and climate are extremely complicated subjects. It is probably a great misrepresentation to say that CO₂ is harmful primarily because of its contribution to a greenhouse effect. As you correctly point out, the albedo change and the difference in optical depth between 350 ppm and 400 ppm are very small. I would go so far as to call them negligible, and I can find a lot of planetary science references to back me up on that. However, and this is critical - the greenhouse effect is only one of many ways that a changing atmospheric composition affects climate. You may want to read climate change, which discusses some of the mechanics, and atmospheric chemistry, which will broaden the view of how carbon and other atmospheric constituents affect conditions on Earth. Nimur (talk) 01:57, 6 December 2009 (UTC)[reply]

You can use a web-based radiative transfer model to help you see that the amount of radiation absorbed at 350ppm is not the same as at 400ppm. It's actually easier to see the difference if you use the pre-industrial value for the concentration of CO2 of ~280ppm and a value we're likely headed towards ~450ppm. -Atmoz (talk) 01:59, 6 December 2009 (UTC)[reply]

Spaceborne measurements of atmospheric CO2 by high resolution NIR spectrometry of reflected sunlight, published in GRL in 1997, is a good quantitative overview of the Carbon Dioxide near-infrared spectrum in an experimental, in-situ, atmospheric context. Nimur (talk) 02:01, 6 December 2009 (UTC)[reply]

The other paper I like to point out in discussions of "global warming" and atmospheric chemistry is this 2003 Eos publication: Are Noctilucent Clouds Truly a “Miner’s Canary” for Global Change. This paper points out some very interesting atmospheric effects - notably, it provides the novice atmospheric scientist with a reminder about conservation of energy. Unless the net power from the sun is changing (which is experimentally not the case), then for any "global warming," there must be some "global cooling" somewhere else - in this case, the mesosphere [1]. Observations of mesospheric weather therefore would be a good indicator of climate change - probably a better indicator than (say) average temperature measurements or atmospheric chemical content. "Of the infrared radiatively most important gases (CO2,O3,O, and perhaps H2O), none can currently be measured with sufficient accuracy at mesopause altitudes to establish its abundance there within anything like percent accuracy, not to speak of any significant long-term change." Therefore, these numbers about Atmospheric Carbon Content are sort of useless - remember, all the quoted numbers are for the troposphere, and almost all the data comes from surface measurements. The actual total carbon content of the atmosphere, per the opinions of the scientists of these papers, is actually very poorly known. On top of this, our only method to probe it is via NIR optical density measurements - and the first paper I linked will give you some idea of the quantitative measurement accuracy for that. Unfortunately, these statements and this line of reasoning sparked huge controversy back in 2003, because it does not tow the simplistic "more carbon ppm = evil" rote argument. But in reality, it's simply establishing an actual scientific context for evaluating the meaning of one particular surface measurement - atmospheric carbon concentration at the surface level. Changing the tropospheric carbon content will certainly result in a different chemistry mechanism in the upper atmosphere, and again, we have extremely complex, non-greenhouse-effect climate-change consequences. Nimur (talk) 02:07, 6 December 2009 (UTC)[reply]

I'm not following the conservation of energy argument. In order for global warming to demand global cooling, the earth would have to be treated as a "closed" system (with a constant and equal input and output). The net input from the sun is assumed constant, but isn't the fundamental argument of the greenhouse effect that the amount of energy radiated from the Earth is decreasing? If energy in is constant and energy out is decreasing, net energy in the system is increasing. Compartmentalizing the system might change the amount of energy locally (at surface or at mesosphere) but the system as a whole can still experience a net increase. Open systems need not obey conservation of energy, and the earth is not a closed system. SDY (talk) 02:31, 6 December 2009 (UTC)[reply]

If the planet temperature increases, its blackbody spectrum will change and it will radiate power faster according to the Stefan-Boltzmann law. Surface temperature may change as a result of greenhouse effect, but planet effective temperature cannot. Nimur (talk) 02:34, 6 December 2009 (UTC)[reply]

According to our articles, Stefan's Law relies on emissivity, and the effective temperature is also a function of albedo. Again, emissivity is arguably what is changing, and changes in albedo (ice has very high albedo, melted ice has less) are also a concern. Why must effective temperature be constant? SDY (talk) 03:25, 6 December 2009 (UTC)[reply]

Nimur, you are complicating things much more than necessary. It is true that the effective temperature does not change. But that does not require cooling of the mesosphere (though some cooling is possible). None of that is required to understand the basic idea behind global warming which is what the question is about. Dauto (talk) 03:17, 6 December 2009 (UTC)[reply]

Ok. What I said above is not entirely accurate. The effective temperature CAN change if earth's albedo change. But it will not change as a (direct) consequence of the increase on atmospheric CO2. Dauto (talk) 04:31, 6 December 2009 (UTC)[reply]

The original questioner noted that a change of 350ppm to 400 ppm does not significantly change the transparency of the entire atmosphere (integrated over the full height) to infrared wavelengths. This is a scientific fact, set forth in the articles I linked. The complexity comes in because climate change can still occur even though the additional CO₂ is not adding to the cumulative greenhouse effect. So, the logical question is - "if climate change is not strictly the result of greenhouse effect, then what is it an effect of?" And, again, the answer is "very complex atmospheric chemistry changes which may result in a different energy distribution in the troposphere." Sorry that this is not a simple answer - but "more carbon = more greenhouse effect" is an overly simplistic and scientifically incomplete picture. Let me succinctly rephrase: adding CO2 may still cause climate changing effects, even if the total change in atmospheric IR absorption is negligible, because other effects come into play. Nimur (talk) 05:27, 6 December 2009 (UTC)[reply]

That's a bunch of nonsense. The additional CO₂ IS adding to the greenhouse effect, and that's why the earth's mean temperature is increasing. Dauto (talk) 14:06, 6 December 2009 (UTC)[reply]

I'm sure that is what you read about in high school science textbooks and the newspaper, but I would suggest moving to a geophysics or planetary science journal to get a more accurate scientific picture. Here is a nice, albeit old, piece from Science: Cloud-Radiative Forcing and Climate: Results from the Earth Radiation Budget Experiment, (1989). Again, experimental and quantitative results suggest that carbon dioxide induced "greenhouse effect" is not the most relevant effect. It may play a role, and anthropogenic carbon may be a root cause of some other changes, but the climate change is not due only to greenhouse effect: "Quantitative estimates of the global distributions of cloud-radiative forcing have been obtained from the spaceborne Earth Radiation Budget Experiment (ERBE) launched in 1984.... "The size of the observed net cloud forcing is about four times as large as the expected value of radiative forcing from a doubling of CO2. The shortwave and longwave components of cloud forcing are about ten times as large as those for a CO2 doubling. Hence, small changes in the cloud-radiative forcing fields can play a significant role as a climate feedback mechanism." Do you really intend to stick to your simplistic model of greenhouse insulation, when experimental observation has repeatedly shown it to be 10 times smaller than other atmospheric physics effects?[2][[3] Even these are small compared to massive climate-scale energy redistributions, e.g. Does the Trigger for Abrupt Climate Change Reside in the Ocean or in the Atmosphere? (2003). To reiterate: the carbon dioxide in the atmosphere is present; it is probably anthropogenic; and its biggest impact on climate is probably not actually related to greenhouse warming, but to other effects that CO2 can induce. Nimur (talk) 15:11, 6 December 2009 (UTC)[reply]

Nimur, I do not deny that there are many complex positive and negative feedback effects that must be taken into account in order to reach a precise quantitative description of climate change. But none of that is necessary to give the OP an answer that makes sense. You said "the additional CO₂ is not adding to the cumulative greenhouse effect". And that's just not true. Dauto (talk) 15:45, 6 December 2009 (UTC)[reply]

It seems that my efforts to link to scientific papers are not getting my point across. Let me make an analogy, which is actually very analogous to the situation (except that CO2 is blocking "upgoing" photons which are re-radiated from the earth... I'm only concerned with the opacity of the atmospheric window, though, so direction doesn't matter). Imagine that you are building a roof, and for some reason you are trying to block light from the sun, and you use thick steel plates to block the sunlight. Each steel plate is 1 inch thick, and blocks most of the photons. For your purposes, you want to really block the sunlight, so you build a giant structure and you put 350 steel plates between you and the sunlight. Now, along comes an upstart engineer, who says he has 50 more steel plates in the scrap-yard, and he's going to add them to your structure, whether you want them or not. Two questions: (1)how much more sunlight are those extra 50 steel plates going to block? Probably none. (2) Are there other problems that those extra steel plates will produce? Absolutely. Your structure wasn't designed for 400 steel plates on its roof.

How does this correspond to the atmospheric carbon situation? Well, the carbon dioxide atoms are narrow-band absorbers of photons. They really only affect a small part of the total solar energy spectrum. And by the time we have 350 ppm, they are pretty much blocking all the sunlight in that particular part of the infrared spectrum. Dauto, you are absolutely correct, in that adding more carbon will increase the absorption - in the same way that adding more steel plates to a roof will block more photons. Because of the way that exponential functions work, this change is negligible. So, if we really have a problem with adding excess carbon, it isn't because of the greenhouse effect or because those carbon molecules will be blocking any extra solar energy. Other effects are the real potential problem - and we need to understand those effects to make sure our roof doesn't collapse under the weight of 50 extra steel plates. Nimur (talk) 16:08, 6 December 2009 (UTC)[reply]

No, Nimur, that is not a good analogy. There is a very good article by Spencer Weart on RealClimate here. Yes, the direct opacity of the atmosphere is not significantly changing when adding more CO2. But what does happen is that the "final" emission layer moves further up the atmosphere, providing more chances for re-emission towards the ground. This is a physical effect, not a chemical process. And while this also is an exponential decay, it still is quite significant - that's why doubling CO2 without feedbacks gives us a ≈1℃ increase in temperature. --Stephan Schulz (talk) 16:30, 6 December 2009 (UTC)[reply]

That is a good read, Stephan. And, as you say, the absorption profile is very relevant as well. Changing the concentration will change the relevant scale height for the near infrared spectral effects. I still disagree with your unsourced assertion that doubling carbon would yield a 1 degree celsius increase in surface temperature. I stand by the references I linked earlier - most importantly, the quantitative analyses of total radiative effects and energy balance experiments - but at this point I think it's moot to argue. Nimur (talk) 16:40, 6 December 2009 (UTC)[reply]

Thanks Schulz. That's finally putting us into the path towards giving the OP a sensible answer to the question asked. The point of the greenhouse effect is not how much of the earth's radiation gets absorbed by the atmosphere. How much of that energy finds its way back to the surface IS the relevant question. Dauto (talk) 16:39, 6 December 2009 (UTC)[reply]

I think you somewhat misrepresented that Eos review: it is about Noctilucent clouds and whether they are signals of climate change, and does not mention anything about conservation of energy. Indeed, the article states that "The temperature will be affected by any anthropogenic changes of the CO₂ and/or O₃ abundances". Your comment that "Unless the net power from the sun is changing (which is experimentally not the case), then for any "global warming," there must be some "global cooling" somewhere else" is wrong as Earth is not a closed system; the cooling occurs in space. Of course atmospheric content affects surface temperature, which is why Mars is freezing, Earth is warm and Venus is toasty. Why are you quoting from 10-20 year old papers about how CO₂ affects climate when there are newer articles on the topic? e.g. [4][5][6] Fences&Windows 16:54, 6 December 2009 (UTC)[reply]

I usually quote papers I've read - sometimes I read them 10 years ago. There's no shortage of new material. But, given that everybody is trying to establish a long-term-change, don't you think it may be worth checking primary source data from previous decades before making bold claims about massive changes in recent years? In any case, ERBE was a great experiment on a great spacecraft, and a hallmark of empirical data collection for global climate studies. It should be cited more often. Nimur (talk) 16:56, 6 December 2009 (UTC)[reply]

That picture above should help make clear why adding more CO2 to the atmosphere increases the surface temperature even after saturation is achieved. The amount of energy cycling between the earth's surface and the atmosphere can be (and is) much larger than the amount of energy coming from the sun. More CO2 increases the energy being fed back to the surface warming it up. Dauto (talk) 22:12, 6 December 2009 (UTC)[reply]

is the difference in heat absorption between the green (300 ppm) and blue (600 ppm) from 20 km of atmosphere anywhere near 14%?

Original questioner here. I understand what's been said, but ~~nobody has addressed my actual question~~: why does the concentration change so slight in bands where the atmosphere is almost completely opaque make any substantial difference in the total amount of absorption? Or to put it another way, the diagram on the right shows the transmission spectra of 300 ppm and 600 ppm. The total amount of energy difference represented by the difference between the blue and green lines isn't anywhere near 14%, is it? What is the actual amount of energy forcing between the actual Earth's atmosphere at 350 ppm and 400 ppm?

Update: I take it back! Stephan Schulz addressed my question correctly at 16:30 above. Thanks Stephan! 99.62.185.148 (talk) 00:53, 7 December 2009 (UTC)[reply]

Size of average Caucasian female head

What is the average size of a Caucasian female head? --I dream of horses (T) @ 02:25, 6 December 2009 (UTC)[reply]

14.4 centimeters. Nimur (talk) 02:29, 6 December 2009 (UTC)[reply]

Slightly in theme, the circumference of the head of a cat is equal to the length of his tail. So, when a cat goes to a hat shop, he only has to let the clerk measure his tail. --pma (talk) 09:40, 6 December 2009 (UTC)[reply]

That sounds problematic for a tailless cat. moink (talk) 11:58, 6 December 2009 (UTC)[reply]

Seems problematic for a headless cat as well. Dauto (talk) 14:01, 6 December 2009 (UTC)[reply]

The problem is moot for a headless cat. --Tango (talk) 15:03, 6 December 2009 (UTC)[reply]

Note however that neither tailless nor headless cats wear hats. --pma (talk) 16:21, 6 December 2009 (UTC)[reply]

Are you sure? I don't think that is entirely true. SpinningSpark 16:44, 6 December 2009 (UTC)[reply]

You mis-read the part about headless and tailless. Nimur (talk) 16:52, 6 December 2009 (UTC)[reply]

I think you're right about Spinningspark but I believe this disproves the first part of the statement although it's difficult to be certain (the tag says it's a manx and there's no tail visible but some manx cats do have a bit of a tail) Nil Einne (talk) 13:40, 9 December 2009 (UTC)[reply]

If I decapitate a hat-wearing cat, the hat might stay on the head, but you (Tango and pma) are saying that "the cat is not wearing his hat" (...because he is not wearing his head). If we assume the essence of being of a cat is based on his brain, we have just proven that a cat's brain is below his neck rather than being in its head. Wanna co-author the paper? DMacks (talk) 18:01, 6 December 2009 (UTC)[reply]

From an answer to a question a few months ago, I have to sadly report that this paper already exists. Essence or no, decerebrate cats are quite alive and do have most of their normal respiratory and gastric functionality intact, because these functions are controlled by the spinal cord and brain stem. Nimur (talk) 18:06, 6 December 2009 (UTC)[reply]

I haven't looked at the paper, but there is a difference between decerebrated and decapitated. The cerebrum is just one part of the brain. --Tango (talk) 23:07, 6 December 2009 (UTC)[reply]

I would define a cat as the combination of a cat's head and a cat's body. If you cut the head of a cat, you no longer have a cat. (The definition is chosen primarily so that you will be wrong, but it is a justifiable definition!). --Tango (talk) 23:07, 6 December 2009 (UTC)[reply]

We're really drifting off topic from the OP's question. Sorry for my contribution to that effect. Per the guidelines, let's stay on topic for the OP. Nimur (talk) 18:11, 6 December 2009 (UTC)[reply]

How do Manx cats get measured for a hat? 78.149.206.42 (talk) 18:00, 8 December 2009 (UTC)[reply]

Human nervous system latency

Resolved

I am looking for the human nervous system latency time. I couldn't find it in the artical nervous system. Basically, I am looking for the number of milliseconds or microseconds between 2 events.

Situation: the human is driving a car and a child crosses the road 20 meters ahead. The driver has to turn the wheel to avoid the child.

Event 1: the light reflected by the child (visual signal) enters the eye of the driver.

Event 2: the hand of the driver starts moving to turn the wheel.

Assume that the human is normal, awake, has not been drinking and attempts to react as fast as possible. I am basically looking for the total latency necessary for these operations: visual signal to reach the brain, brain processing of the signal and recognising danger, brain making decision to turn the wheel, brains instructing hand to turn the wheel, then message to transit from brain to hand and arm muscles, and finally, muscles to begin contractions. I don't need the split between the operations, just the total number of milliseconds between event 1 and event 2. Could you please help? This is not homework question :-) --Lgriot (talk) 03:27, 6 December 2009 (UTC)[reply]

Reaction time is probably the best we have; it cites 180-200 milliseconds to detect a simple boolean visual stimulus; your instance is a much more involved problem and so you can, I think, expect the reaction time to be greater. --Tagishsimon (talk) 03:37, 6 December 2009 (UTC)[reply]

Thanks, that is exactly what I was after. --Lgriot (talk) 04:48, 6 December 2009 (UTC)[reply]

In the Highway Code in the UK there are a set of stopping distances for a variety of speeds. In that publication, stopping distance is given as the sum of thinking distance and braking distance. Thinking distance is invariably given as the distance in feet being equal to the speed in mph. So the estimated time to see something happen and shift a foot to the brake pedal (similar to seeing something and steering) is estimated by the UK driving authorities as about 0.7 seconds. --Phil Holmes (talk) 11:25, 6 December 2009 (UTC)[reply]

That's not exactly the same, though, even though I doubt it would matter much in practice. You hopefully always drive with your hands on the steering wheel, but I'm guessing the same can't be said for having a foot on the brake all the time. -- Aeluwas (talk) 14:18, 6 December 2009 (UTC)[reply]

Interferomics possible editorial problems

I recently came across this article and after doing some corrections noted that the term was coined by researcher Gaurav Rana, when I reviewed the history the article was created by User:Gauravsjbrana, a subsequent google search revealed this article [jmd.amjpathol.org/cgi/reprint/9/4/431.pdf] which mentioned the emerging field of Interferomics in 2005 however makes no attribution to Gaurev Rana. I see a number of issues here firstly it is a specialized field so inaccurate editing maybe remain undetected, second it appears to be self promotion, thirdly it could be false representation. I am hoping someone with more experience in these matters can take a look. Matt (talk) 03:57, 6 December 2009 (UTC)[reply]

edit - oops it appears I may have asked this question in the wrong place
please ignore this article I have posted a welcome to this user and a short note regarding the possible issue with the article Matt (talk) 04:21, 6 December 2009 (UTC)[reply]

my son ( 10 yearls old )

Removed request for medical advice. Wikipedia cannot give medical advice. Only a medical professional can give responsible medical advice.

William Thompson

What substantial contribution did William Thompson make in the field of physics? Kittybrewster ☎ 12:34, 6 December 2009 (UTC)[reply]

I suspect you're thinking of Lord Kelvin. - Nunh-huh 12:45, 6 December 2009 (UTC)[reply]

Indeed. Thank you. Kittybrewster ☎ 13:13, 6 December 2009 (UTC)[reply]

Pub quiz question? Fences&Windows 13:30, 6 December 2009 (UTC)[reply]

Science test paper. "Homework for Grown-ups". Kittybrewster ☎ 13:59, 6 December 2009 (UTC)[reply]

Maybe we should but the disambig link to the Thomson page a bit higher on that page? It seems like a pretty easy mistake to make. --Mr.98 (talk) 14:36, 6 December 2009 (UTC)[reply]

Thought the same thing... --Stephan Schulz (talk) 15:34, 6 December 2009 (UTC)[reply]

I couldn't see him anywhere on that page! I'll go and add him. Dmcq (talk) 16:20, 6 December 2009 (UTC)[reply]

Well, the issue is that he doesn't have a p in his name, so ol' Lord Kelvin himself doesn't belong on that page... I've done something like what I think might be useful (putting the non-P see-also at the top, rather than at the bottom). --Mr.98 (talk) 16:43, 6 December 2009 (UTC)[reply]

If we want to increase the usefulness of disambiguation pages, we shouldn't insist on exact spelling. Similar spelling or similar pronunciations should be enough; the pages are so that articles that could be confused with each other can be found and distinguished. There should be one Thomson/Thompson disambiguation page for each Thomson/Thompson, with appropriate redirects pointing to it. - Nunh-huh 23:10, 6 December 2009 (UTC)[reply]

Not to mention Tomson or even Tompson (although there are only two of those). Mikenorton (talk) 23:21, 6 December 2009 (UTC)[reply]

How long are viruses active?

When you are suffering from the Common cold you are spewing cold viruses all around your home or workplace when you cough and sneeze. How long can these viruses stay active and possibly infect someone else? And what eventually happens to them -- do their molecules eventually disintegrate, or do they just spread out so much that they can no longer cause an infection? —Preceding unsigned comment added by Fletcher (talk • contribs) 10:37, 6 December 2009

A quick search of the reference desk archive (box at the top of this page) for 'virus "outside the body"' yields a link to a relevant discussion. Also, our Common cold article has some relevant info, though I would agree that those resources don't answer your question directly (I did not search the RefDesk exhaustively, so others may find a really good answer to what seems like it would be a frequently asked question). Virus survival in the environment varies widely based on environmental conditions. How those conditions affect viral infectivity depends on viral characteristics. For example, the most common cause of a cold is one of the many serotypes of Rhinovirus. Rhinoviruses are picornaviruses, which have a RNA genome, making them more susceptible (than DNA viruses) to genetic damage (which would render them noninfectious); making them much more resilient, though, is their lack of lipid coat such that they survive complete drying. Additional issues include the amount of virus shed, since a heavily-shed virus (relative to its infectious dose) will remain infectious longer. It seems clear that cold viruses can remain infectious for days (PMID 6261689, full text here), at least under some conditions (keep in mind that virus from your nose would never be in "buffered water", and drying in the presence of albumin, as they did in some experiments that showed more prolonged infectivity, is closer to the normal situation). This article references earlier studies on environmental persistence of infectious rhinoviruses, and the efficacy of various disinfection measures. There's also an interesting study of flu virus viability relative to environmental conditions. -- Scray (talk) 17:11, 6 December 2009 (UTC)[reply]

Thanks, very helpful! Fletcher (talk) 17:58, 6 December 2009 (UTC)[reply]

Burns and clothing vs. bare skin

Are burns more or less severe when the burn area of the victim is covered by clothing? That is, does clothing, as opposed to bare skin, alleviate or exacerbate the severity of burns? I assume that it probably depends on the type of burn, so could the question be answered for the various types of burns (chemical burns, electrical burns, hot oil burns (that is, cooking oil), open flames, radiation burns, and steam burns)? —Lowellian (reply) 17:07, 6 December 2009 (UTC)[reply]

First Aid for Soldiers [7] distinguishes between natural and synthetic materials (roughly). "Caution - Synthetic materials, such as nylon, may melt and cause further injury." They also distinguish between the cases whether the fire and flames are still burning on the clothing, or if the flames are extinguished. After the situation is safe, the general instructions are to expose the burn by cutting and gently lifting clothing away, but leaving in place any cloth or material which is stuck to the burn area. They also have special caveats for cases of chemical burns and blisters. Following treatment, the entire area is re-covered in sterile field dressing, to protect the burn area. Nimur (talk) 17:38, 6 December 2009 (UTC)[reply]

Thanks, but I wasn't asking how to treat clothing burns; I was asking whether burns are less or more severe against clothing or against bare skin. That is, does clothing have protective value against burns, or do they only exacerbate burns? —Lowellian (reply) 17:45, 6 December 2009 (UTC)[reply]

Of course, it depends on the clothing. As noted above, nylon will melt and exacerbate the burn. Conversely, an asbestos apron or a flame-retardant PPE will not burn and will also insulate the victim from heat. Materials like (real, non-synthetic) leather will probably serve a pretty good protective role. The more uncertain case are fibers like cotton or wool, which will burn. These will probably exacerbate a burn and may increase the contact-time with the flame/heat source, but it depends on conditions. In some cases, the flame may actually carry more heat away than it produces, but in general I think the direct exposure is a bad thing. Nimur (talk) 17:51, 6 December 2009 (UTC)[reply]

(ec) Clothing is a blessing and a curse. It acts as a physical block, preventing as much "burning agent" from getting to the skin. For example, fabric insulates or slows heat transfer, absorbs small hot-oil drops so they cool before soaking through (if they soak all the way through at all), keeps as much concentrated sulfuric acid from reaching one spot, etc. And certain fabrics are well-designed to block penetration specific burning agents. But once the cause is removed, the clothing keeps the burning agent (what's left of it) close to the skin, leading to prolonged burning. For example, the soaked fabric is still transferring heat or sulfuric acid to the skin. And the results of the fabric exposure to the burning agent can have additional effects beyond "whatever the burn itself is" (see Nimur's comment about synthetic fabrics melting). So the "cause of the burn" isn't removed until the fabric is. DMacks (talk) 17:54, 6 December 2009 (UTC)[reply]

Greenhouse Gases

How is it that CO2 rises in the Atmosphere when it is heavier than Air?Taskery (talk) 18:10, 6 December 2009 (UTC)[reply]

Convection, or mixing of gases, is the dominant descriptor of the troposphere. This means that because of uneven heating and turbulent fluid motion, things like wind and updrafting occur, resulting in a "well-mixed" gas distribution. At higher altitudes (notably, first the stratosphere, stratified on temperature; and above, the mesosphere, layered based on chemical content), gases separate out based on their velocity or molecular mass, but this is not the case in the lowest regions of the atmosphere. Note that there are some exotic mechanisms which can carry CO2 to even higher than equilibrium altitudes. Middle Atmosphere Dynamics is a good book if you are interested in some other ways CO2 can "float" its way up. Nimur (talk) 18:16, 6 December 2009 (UTC)[reply]

The region of atmosphere that is well-mixed is called the turbosphere or homosphere, and is separated from the heterosphere by the turbopause, which is usually well above the stratosphere. --Stephan Schulz (talk) 18:31, 6 December 2009 (UTC)[reply]

Knives and electrical sockets

I have heard it said that it is dangerous to stick the tip of a knife into an electrical socket. But as long as the knife is non-metal (e.g. plastic knife) or has a non-metal handle, I don't see why this would be any more dangerous than sticking an ordinary electric plug into the socket. I don't mean digging deep into and actually cutting up the socket; I mean just sticking the tip in as far as it will go without forcing. A plastic knife wouldn't even conduct, right? And wouldn't the wooden or plastic handle on a metal knife serve as insulation from the metal blade the same way that the plastic or rubber base on an electric plug serves as insulation from the metal prongs? —Lowellian (reply) 18:34, 6 December 2009 (UTC)[reply]

An electric appliance provides an electrical path from the live wire to the return wire. If you stick things in the outlet, you are the easiest electrical path to ground - so even if you are insulated, it's still less safe than plugging in an appliance cord. Nimur (talk) 18:42, 6 December 2009 (UTC)[reply]

A plastic or wooden knife won't conduct unless it is wet. Most knives are metal, though, and even for ones that have a plastic or wooden handle, you will usually see, if you look at them closely, that they aren't easy to grasp in a way that avoids touching any metal. Looie496 (talk) 18:49, 6 December 2009 (UTC)[reply]

The pins of the electrical plug are of a standardized length - it's possible that a longer blade might short out the wires behind the socket too. But I agree that 110v (or even 240v) isn't going to arc though the plastic handle of a knife any more than placing your finger against the plastic housing of the electical socket is going to result in electricity jumping into your body. But these kinds of advice are put out there for the average knucklehead who hasn't noticed that the plastic side-plates of his knife are held on with a couple of brass rivets - and touching one of them might result in a shock. I've stuck electrical screwdrivers and volt-meter probes into electrical sockets dozens of times - but it always has to be a matter of thinking out each move carefully before you do it. Where are you going to be putting your fingers - where will the current flow. The trouble is that 99% of people don't do that - so "Don't stick knives into electrical outlets!" is very good advice. SteveBaker (talk) 20:57, 6 December 2009 (UTC)[reply]

Actually I'd hope that the plastic housing of the electrical socket would be explicitly designed as a good insulator, whereas the plastic knife probably would not be. Thus it might be easier for the electricity to arc through the knife than the socket. Mitch Ames (talk) 11:59, 7 December 2009 (UTC)[reply]

Why would you even want to do that? Do you stick beans up your nose? —Preceding unsigned comment added by 79.75.87.13 (talk • contribs) 16:46, 6 December 2009

Science games for kids

Christmas is rolling up and I will be spending some of it in the company of little ones, say toddler-ish to ten years old or so. I would like to have ideas of what to do with them, to test their scientific knowledge and cognitive development in (as the kids say) the funnest way possible. These need to be simple things to do, without fancy equipment. I am thinking of things like pouring liquid from a tall thin glass to a short wide glass, asking them which glass holds more, and seeing at what age the kid "gets" that the volume is the same. Any ideas for how I can approach this? Needless to say, my young relatives and friends' kids are very brainy babes. BrainyBabe (talk) 19:26, 6 December 2009 (UTC)[reply]

Quantum Physics: Explained through Interpretive Dance. Nimur (talk) 20:04, 6 December 2009 (UTC)[reply]

This may be a bit tough for 10 year-olds - but kids vary a lot: [8] (from my personal Wiki). SteveBaker (talk) 20:06, 6 December 2009 (UTC)[reply]

I was unable to get your human hair width measurement experiment to work at all. I made an honest effort, but it was very hard to get diffraction fringes. I was able to get diffraction fringes by shining the laser through two razor blades closely spaced, but not around a human hair. Nimur (talk) 20:11, 6 December 2009 (UTC)[reply]

Ah Christmas: Standard keeping quite ones for brainies of that age are 142857 (get them to multiple it by 2,3,4,5,6 and guess what 7x is), which day of the week has an exact anagram, lateral thinking games (hanged man and puddle, dwarf and lift, anthony and cleopatra, surgeon "thats my son" etc.), which two digit prime has a square which looks the same upside down and in a mirror, wire through an ice block... I am sure other people know squillions... --BozMo talk 20:10, 6 December 2009 (UTC)[reply]

Balancing two forks and a cocktail stick on the edge of a wine glass...whats the algo to find the dud ball out of ten with balances and only three weighing... fox/ chicken and grain with a river boat... the various logic puzzles with black and white hats Prisoners_and_hats_puzzle Hat_puzzle... --BozMo talk 20:13, 6 December 2009 (UTC)[reply]

Surely 9 balls and two weighings would be more challenging? - Jarry1250 ^{[Humorous? Discuss.]} 21:38, 6 December 2009 (UTC)[reply]

The version I know you are not told if the dud is too heavy or too light. That makes nine and two impossible and ten and three hard (especially for people who start off by putting five on each side). But I am sure there are loads of variants/ --BozMo talk 21:45, 6 December 2009 (UTC)[reply]

There's a book called "Physics for Entertainment" ("Zanimatel'naya fizika" in Russian original) by Yakov Perelman. I remember enjoying it immensely when I was a kid. It was written in 1930's, so it does not rely on the modern technology; but that does not make it any less fun. I know it has been translated into English, although I am only familiar with the Russian version. You can try finding the English version in the library. --Dr Dima (talk) 21:09, 6 December 2009 (UTC)[reply]

The trick using slaked cornflour never ceases to amaze... Make up a goo using cornflour (cornstarch for our American cousins) and water to the consistency of runny double cream. If you bang the container on the table and invert it over the head of the nearest brat it won't spill if you do it properly! --TammyMoet (talk) 10:24, 7 December 2009 (UTC)[reply]

These all sound great for the older kids, but I said brainy, not genius! I think several-digit multiplication is beyond the toddler set. There are some tempting phrases to google here: I'd never heard of slaked cornflour, so thank you all, and keep 'em coming! BrainyBabe (talk) 22:54, 7 December 2009 (UTC)[reply]

Slaked cornflour (more colorfully known as "oobleck") is just regular cornflour and water mixed at just the right consistency. It is a classic non-newtonian fluid - it behaves very strangely. If you do violent things to it, it behaves like a rubbery solid - if you prod it gently, it's a pretty runny liquid. I'm sure you could come up some neat things to do with it - but you're going to need to experiment a bit to get the right consistency. SteveBaker (talk) 04:14, 8 December 2009 (UTC)[reply]

Google "red cabbage juice indicator". Red cabbage juice is a good acid base indicator and basically will go through the entire rainbow of colors depending on pH. Kids can have fun slowly adding acid or base to red cabbage juice (basically the water that red cabbage has been cooked in) and watching the colors change. Not sure what kind of game this would make, but little kids like all of the pretty colors. --Jayron32 23:20, 7 December 2009 (UTC)[reply]

Diesel automobiles without diesel particulate filters

I want a list of the currently produced diesel automobiles which aren't available with a diesel particulate filter. --84.62.213.156 (talk) 20:34, 6 December 2009 (UTC)[reply]

Cartography - spherical map - globe section

Encyclopaedia Britannica (CD, 2006)- Student library - Maps and Globes: "A useful compromise between a map and a globe, provided that not to much of the Earth has to been shown, is the spherical map, or globe section. This is a cutaway disk having the same curvature as a large globe. It is usually large enough to show an entire continent. A spherical map shows the shape of the Earth accurately but is much cheaper to produce and much easier to carry and store than a globe." Are there really such things? I ask a german cartographer, he has never heard of this. I could not find a single link on google regarding this globe sections. What is the exact scientific term for such a map? I am witing on the german article Globe (de:Globus). --Politikaner (talk) 21:31, 6 December 2009 (UTC)[reply]

I found one old reference here [9] (there are a few of similar vintage [10]) to the use of spherical maps that were segments of globes, presumably that is what the Britannica is talking about, but no modern references yet. Mikenorton (talk) 21:44, 6 December 2009 (UTC)[reply]

Slightly more recent reference, (1956), [11] (look at the bottom of page 317) which refers to the "design and production of spherical map sections displaying a portion of the globe at a scale of 1:1,000,000". Mikenorton (talk) 21:53, 6 December 2009 (UTC)[reply]

Have you tried Map projection as a starting point? --BozMo talk 23:22, 6 December 2009 (UTC)[reply]

If I'm interpreting it correctly, we're talking about maps shown on segments of spheres, so no projection is necessary. --Tango (talk) 23:32, 6 December 2009 (UTC)[reply]

Or do they mean like this: [12]? --BozMo talk 23:29, 6 December 2009 (UTC)[reply]

As far as I understod from your answers, this spherical maps where only marginal in cartography and are now history. I will integrate the scarce information and the links in my article. Thank you for your help. --Politikaner (talk) 21:59, 8 December 2009 (UTC)[reply]

Cholesterol and sodium

Does exercise get rid of cholesterol and sodium in addition to fat? --75.33.216.153 (talk) 21:38, 6 December 2009 (UTC)[reply]

Sodium levels are controlled by osmotic systems. Being ionic and very water-soluble it is easy to get rid of excess (simply drink more water and urinate more). I really think cholesterol is an endogeneous thing. Ingested cholesterols only account for a small fraction of cholesterol supply; the rest is produced as a pathway related to fatty acid synthesis. Thus the only practical solution to controlling cholesterol is via medication that can inhibit those pathways. See COX-1 and COX-2. John Riemann Soong (talk) 01:03, 7 December 2009 (UTC)[reply]

Vigorous exercise will generally cause you to sweat, sweat contains sodium - so yes, your sodium levels will decrease (sometimes to pathologic levels, see hyponatremia). Cholesterol is a cell-wall component, I don't think it features in any primary catabolic (energy-producing) pathways, though if you exercise to the point of muscle wasting you'll probably be burning cholesterol along with everything else. However, reading the cholesterol article, total fat intake plays a role in serum cholesterol levels, which suggests to me that if exercise helps to burn off circulating lipids in the blood serum before the liver can synthesize cholesterol, less cholesterol will be produced - but I'm not positive on the timeframes involved. Franamax (talk) 01:41, 7 December 2009 (UTC)[reply]

I'll defer here to the two responses below, which while not directly sourced seem to me entirely reasonable. Absolute levels of sodium will decrease with exercise, but relative concentration apparently may not and I don't know enough about ion transporters in the cell wall to have an opinion on how (primarily) nervous system function is affected. And if HDL itself is catabolized (rather than being recycled as a marker molecule), that too I am unfamiliar with. So best to just ignore my whole post maybe. :) Franamax (talk) 04:02, 7 December 2009 (UTC)[reply]

Sweating doesn't reduce your sodium levels: it's hypotonic fluid, its sodium concentration is lower than the rest of your extracelluar fluid. When you sweat, you're losing more water than sodium. It's replacing sweat with hypotonic fluid of an even lower sodium concentration (water) instead of an isotonic or hypertonic replacement (e.g. Gatorade) that would lower your sodium levels. - Nunh-huh 01:57, 7 December 2009 (UTC)[reply]

Exercise can be beneficial to blood cholesterol levels, which is all anyone cares about. Your body is full of cholesterol, but its only the stuff that clogs your arteries that makes any difference. Cholesterol ends up in the blood in two forms, HDL cholesterol and LDL cholesterol, these are respectively "good" cholesterol and "bad" cholesterol. People often miss why we test for blood cholesterol. Its not the cholesterol per se which is always bad, its that the cholesterol is a marker for things that are going on in your body. HDL and LDL are used as chemical tags attached to molecules in your body that tells them where to go. HDL is associated with catabolic processes, that is molecules taged with HDL are basically heading to be broken down. LDL is associated with anabolic processes, that is those molecules are heading somewhere to be added to your body. In general, having an excess of LDL means your body is growing, so LDL can indicate an excess of caloric intake, high blood sugar levels, and a general trend of increasing fat storage. Higher HDL levels are generally associated with lower blood sugar levels, breaking down fat, and lower overall caloric intake. There are lots of other factors involved, but exercise in itself can improve cholesterol ratings because exercise increases catabolic processes in your body by using up stuff for energy, especially fat stores. --Jayron32 03:16, 7 December 2009 (UTC)[reply]

Well LDL is also "inherently" bad in that it promotes (i.e. it's more than a marker) lipid accumulation in blood vessels right? Otherwise why would people use statins? John Riemann Soong (talk) 05:31, 7 December 2009 (UTC)[reply]

Because LDL-tagged lipid molecules tend to drift around the blood until the glom onto each other. HDL-tagged molecules are heading to the liver to be "eaten up", so they don't hang around a long time. The essentially get filtered out. LDL-tagged molecules are basically saying "We're ready to be used to build new cells" and if there isn't anywhere in the body that needs lots of new cells, these molecules just hang around until they accumulate in veseels and cause a mess. So yes, LDL-cholesterol can, of itself, cause problems, but the underlying concern can still be addressed, in many people, by some amount of behavioral modification; i.e. to exert control over those processes which decrease anabolism (lower blood sugar) and increase catabolism (more exercise). There's also been some interesting research out that people who use cholesterol lowering drugs like statins may not have much significant positive health outcomes; that is while their cholesterol numbers may be significantly lower, they don't have significantly lower incidents of cardiovascular disease. It seems somewhat like a case of covering up a problem rather than fixing it. It doesn't mean a whole lot to lower your cholesterol if doing so doesn't have an effect on the quality or length of your life. The only people for whom statins actually show positive outcomes are those for who actually have active heart disease. For people with no known heart disease symptoms, while statins do lower cholesterol numbers, they don't actuall seem to reduce the risk of emerging heart disease. See this article from CBS news which explains some of the controversy, and this article (subscription required) from a peer-reviewed journal. The CBS article actually makes some good points about advertising used in the case of Lipitor; the ad claims percentage improvements based on some pretty shoddy statistics. In the case cited, those taking Lipitor saw an incidence of 2 heart attacks per 100 people, and those taking placebo say an incidence of 3 heart attacks per 100 people. The question then becomes whether widespread prescription of Lipitor results in net positive health outcomes for the most people, given that it isn't preventing that many heart attacks among the general, healthy, population and that it does have documented side effects which need to be taken into account. --Jayron32 18:15, 7 December 2009 (UTC)[reply]

Why aren't rugby players overwhelmed with injuries?

In gridiron football, the players wear helmets and padding. Even with that protective equipment, concussions, broken bones, torn tendons, and other serious injuries occur frequently. So how is it possible that rugby players, who also play a full-contact sport and don't wear any protective equipment at all, aren't overwhelmed with more frequent and severe injuries? —Lowellian (reply) 21:52, 6 December 2009 (UTC)[reply]

Rugby players do wear some protective equipment (Rugby union#Equipment). It is against the rules to tackle above the shoulders, and I think there are rules about how many people can tackle a player at once. I don't know if similar rules exist in other forms of football. --Tango (talk) 22:29, 6 December 2009 (UTC)[reply]

Yep. Also see Rugby_union_equipment#Body_protection. There is an injury rate I think its about 300 injuries per 100,000 hours played but I easily could be a factor of ten out: anyway about ten times higher than most other sports I seem to recall, my mum was a school doctor and it was in one of her books. But also a large number of rules evolved over a long time to minimise injury, not just no neck tackle but no tackling in the air, no collapsing scrums, no playing when down etc etc. I am not sure that many players wear anything other than a mouthguard as protection despite some light padding being allowed (sometimes there is a bit in a Scrum cap to protect Cauliflower_ears). And of course it is not a complaining culture: even at school level players with broken bones (fingers for example) sometimes carry on to the end of a match which is allowed as long as there is no blood flowing but obviously a bit daft. --BozMo talk 22:43, 6 December 2009 (UTC)[reply]

Come on! We all know the real reason is that Americans are weak sissys who wouldn't survive half an inning of a real Englishman's game like rugby or contract bridge! --Stephan Schulz (talk) 23:31, 6 December 2009 (UTC)[reply]

I know they slam you around in bridge, especially when you're most vulnerable ... but innings? Clarityfiend (talk) 23:46, 6 December 2009 (UTC)[reply]

Well, yes. Aside from their padded version of Rugby (which I played in school and is unbelievably dangerous!), American sports are most British 'girly' games that have been adapted into tamer forms for American men to play. Baseball is really just "rounders" - which is played almost exclusively by girls in the UK (and has been since Tudor times) - and Basketball is really just "netball" (since 1890 at least). Hockey is really hockey with padding and a nice slippery surface so you can't get a decent grip before you whack your opponent with a bloody great stick - but, again, it's mostly a girly game in the UK. That leaves golf...'nuff said? (And you can get some wicked paper-cuts in contract bridge when the play gets rough!) :-) SteveBaker (talk) 23:50, 6 December 2009 (UTC)[reply]

Baseball, basketball, hockey (what you 'pedians call "Ice hockey" for some reason) and gridiron football are all Canadian inventions. We came up with them to distract attention from lacrosse, which is basically just hitting each other with sticks for 60 minutes. :) Franamax (talk) 01:49, 7 December 2009 (UTC)[reply]

That's an odd statement. Baseball (aka Rounders) has been around in the UK since 1745..that makes the sport 123 years older than Canada (est 1867). Basketball (aka Netball) was first played in the UK in 1890's - no mention of Canada there. Our article on Gridiron football says the gridiron started out in Syracuse University (NewYork, USA). I guess we're going to have to demand some reference here. Lacrosse...yeah - that's a pretty serious sport. Hockey - but without the rule about the stick not being higher than shoulder-height - allowing some pretty decent head-shots. Yeah. The only trouble is that I can't think about lacrosse sticks without thinking about the delicate young ladies of St. Trinians. SteveBaker (talk) 03:26, 7 December 2009 (UTC)[reply]

Sources, could be a problem for sure, that's why I confined myself to small print. Abner Doubleday codified the current rules of baseball (more or less), I read somewhere he came from Ontario (could be wrong); James Naismith set up modern basketball, an expat Canadian; Football, again my reading has been that it was codified as a Canadian university sport, then watered down to give the wimpy Americans one extra try with the fourth down :) ; hockey - oh yeah, we still get the head-shots, the euphonisms are "combing his hair" and "laying on the lumber a bit" although the incidence has decreased drastically. Lacrosse, well all due respect to the ladies, but when the Toronto Rock take the field, wearing shorts and short-sleeved shirts i.e. no body protection whatsoever in those areas - yeah, it's a scene man... :) (But I will retract anything I can't source immediately, which is mostly everything I just said) Franamax (talk) 03:45, 7 December 2009 (UTC)[reply]

Canada has a perfectly legitimate claim to both Basketball and Gridiron Football. Basketball was invented in the U.S. (we luckily have documentation on that one) by James Naismith in about 1891 (Netball came a few years later, and is specifically a derivative of it). Naismith was in the U.S. when he invented the sport, but he was Canadian by birth. Gridiron Football was essentially invented by Walter Camp, but his changes were basically modifying the existing forms of football in the U.S., which were predominately recognizable as Rugby. Since rugby was introduced to U.S. colleges by McGill University, one can claim that McGill had a large role to play in introducing modern Gridiron codes of football. However, there is not one inventor of either of these games, just that Canadians played a prominent role in both of them. --Jayron32 05:21, 7 December 2009 (UTC)[reply]

(Without evidence) There are several possible reasons for this. One is that if you have all of that padding & protection, you can tackle harder without risk of hurting yourself - therefore it may be that well-padded players are simply hitting with harder surfaces (helmets, for example) and with more power than an unprotected player could. Secondly - there is a phenomena where people are prepared to accept a certain level of risk in what they do - and improving the protection simply makes them take larger risks. When seatbelts were first mandated for cars, the number of injuries in car accidents decreased sharply - but it has gradually crept back up as people now feel safer and are therefore increasing the risk back to where it was before the seatbelt laws. Perhaps, with less risk to self, the guy with the odd-shaped ball is less careful about avoiding situations where he might be tackled. SteveBaker (talk) 23:50, 6 December 2009 (UTC)[reply]

I'm sure I heard somewhere that, because of this, rugby has more injuries but American football has more fatalities. Vimescarrot (talk) 01:32, 7 December 2009 (UTC)[reply]

This article [13] lists a bunch of fatalities amongst Fijian rugby team - so Rugby players clearly do die during professional play. The only recent references I could find to fatalities in American football were heat-related fatalities amongst young players - not due to collisions during play. But PubMed [14] says that close to 500 people have died from brain-related injuries and that was 70% of all fatalities - but mostly amongst children. So we should guess around 710 fatalities since the 1940's - so maybe 80 or so fatalities per year. The Canadian public health people [15] found zero Rugby fatalities between 1990 and 1994. But it's really hard to gather fair statistics because Rugby is played in a LOT of countries - and American football in just a handful - but the number of people involved seems higher in the US and Canada than in other countries. SteveBaker (talk) 03:43, 7 December 2009 (UTC)[reply]

I don't have any hard statistics (although did come across this which hints at it [16] in relation to discussion on Max Brito who suffered a spinal cord injury at 1995 Rugby World Cup and became tetraplegic) but it's my understanding most serious rugby injuries are at the lower levels of play, i.e. not involving the top professionals and that this isn't just because of the obviously significantly greater numbers but because of the greater experience and knowledge of how to avoid serious injuries and how to avoid causing serious injuries and also because they tend to be fitter. At a guess I would presume it's the same for American football/gridiron but I don't really know. There are a variety of articles here [17] [18] [19] [20] [21] [22] which I come across dealing with rugby injuries particularly spinal cord ones which may have some useful statistics Nil Einne (talk) 11:35, 7 December 2009 (UTC)[reply]

As a single data point, I can offer a distant uncle who died tragically young from a broken neck. Rugby at university, after winning a scholarship. The first of his family to go. So, at that level, people certainly have died. 86.166.148.95 (talk) 20:03, 7 December 2009 (UTC)[reply]

A long time later but came acros this while searching for something else. One point I forgot to mention is there's likely better medical attention and care, particularly initially (which includes people not doing completely daft things like moving someone who may have a spinal injury without an appropriate brace when it isn't absolutely essential). Nil Einne (talk) 04:13, 18 June 2011 (UTC)[reply]

I think some good points have already been made but a key point which hasn't been mentioned yet that I noticed is that in Gridiron/American football players are tackled regardless of whether they have the ball. While I don't play nor have any interest in the sport it's my understanding one of the key expections is that every player tries to tackle a rival player. This compares to rugby where you only tacke a player with the ball. Also just repeating what was said above, a number of rules in rugby have evolved to try & reduce injury. I came across [23] which may be of interest with comments from two people who've played both sports. Nil Einne (talk) 11:27, 7 December 2009 (UTC)[reply]

Several sites seem to indicate that a lot of rugby injuries happen in the scrum...not so much during tackles. SteveBaker (talk) 14:35, 7 December 2009 (UTC)[reply]

Precisely. ~ Amory (u • t • c) 16:35, 7 December 2009 (UTC)[reply]

This is also mentioned in our Scrum (rugby union)#Safety of course. I didn't mention this earlier but it's probably the key area of focus in the attempts to to reduce the risk of injury (the 2007 rule change mentioned in Scrum (rugby union)#Safety for example). Some of course suggest an end to contested scrums ala Scrum (rugby)#Rugby league but as the earlier article says, there's little support for that. There is I think a simple code of ethics that if anyone yells 'neck' during a scrum, you stop pushing (but probably don't pull out of the scrum since if the guy's neck is injured that's not going to help) which is described here [24]. (Such codes of ethics aren't of course that uncommon in sport when they're called for.) That site also mentions a number on injuries primarily in American football players. BTW I also came this story [25] on Gareth Jones (rugby player) a professional Welsh rugby player who died last year just to emphasise it isn't just in countries like Fiji that they happen. Nil Einne (talk) 17:54, 7 December 2009 (UTC)[reply]

I'll also add (I don't think it was mentioned above) that since you cannot pass forward in Rugby, there is a much larger emphasis on speed, agility, and overall athleticism. In (American) Football, there is an emphasis on either throwing far or being really, really big. You want a players who can run like the devil, but the emphasis still comes from the throws, not avoiding getting hit. ~ Amory (u • t • c) 16:35, 7 December 2009 (UTC)[reply]

Are there any other types of radiation besides electromagnetic radiation?

Hi! I would like to ask if there's any other types of radiation besides electromagnetic radiation? By electromagnetic radiation I mean all of it's subcategories from gamma rays to infrasound. Thank you for your help!JTimbboy (talk) 23:19, 6 December 2009 (UTC) —Preceding unsigned comment added by JTimbboy (talk • contribs) 23:18, 6 December 2009 (UTC)[reply]

There's gravitational waves. Of the four fundamental forces, only electromagnetism and gravity work over long distances, so only they really radiate in a noticeable way. There are also cosmic rays, but they are actually particles. --Tango (talk) 23:27, 6 December 2009 (UTC)[reply]

What definition of radiation are we using here? The standard one contains lots of non-EM radiation (e.g., alpha particle, beta particles, neutrons, etc.). Sound is "acoustic radiation". --Mr.98 (talk) 00:24, 7 December 2009 (UTC)[reply]

Two points. First: Infrasound is not a kind of electromagnetic radiation. Second: Being made of particles is not a reason to exclude cosmic rays from the list of radiations since light is also made of particles. Dauto (talk) 04:22, 7 December 2009 (UTC)[reply]

Out of curiosity, if light is ambiguously photon/energy, do the same particles exist for different wavelengths? I.e. are there "photons" in X-rays and in the infrared? SDY (talk) 17:01, 7 December 2009 (UTC)[reply]

Yes. All types of electromagnetic radiation are essentially the same; there's nothing special about the stuff our eyes happen to be able to see. Shorter-wavelength radiation corresponds to higher-energy photons. Algebraist 17:05, 7 December 2009 (UTC)[reply]

The relationship between quantization energy and wavelength is defined by the Planck constant. SpinningSpark 17:08, 7 December 2009 (UTC)[reply]

(ec) All wavelengths of light are made up of photons. Different wavelengths are made up of photons of different energies (E=hf - the energy per photon is the Planck constant times the frequency). --Tango (talk) 17:08, 7 December 2009 (UTC)[reply]

Thank you for your advice! Sorry, I mixed up infrasound with extremely low radio frequency, because they have a bit coinciding frequency. Could anyone give me examples of particle only radiation (I hope that radiation is the right word to discribe it)? And examples of radiations that work over short distances too?JTimbboy (talk) 15:24, 7 December 2009 (UTC)[reply]

Alpha radiation, beta radiation and cosmic rays are all forms of particle radiation (I should say fermion radiation since, as Dauto points out, light can be thought of as being made of particles). When I mentioned short range forces I was talking about the strong nuclear force and the weak nuclear force. They only work on the scale of atoms and smaller and the particles involved are almost always virtual particles, so can't really be thought of as radiation. --Tango (talk) 15:39, 7 December 2009 (UTC)[reply]

There is also neutrino radiation which is of some importance to astronomy. See Cosmic neutrino background and Neutrino astronomy. There is a large burst of neutrino radiation from supernova explosions. SpinningSpark 16:51, 7 December 2009 (UTC)[reply]

Muons are an important component of the secondary radiation created by cosmic rays when they strike the atmosphere. 169.139.217.77 (talk) 00:42, 8 December 2009 (UTC)[reply]

Total acres in California?

How many acres are in the entire state of California? —Preceding unsigned comment added by 98.248.194.191 (talk) 23:32, 6 December 2009 (UTC)[reply]

104,765,440. --Tango (talk) 23:33, 6 December 2009 (UTC)[reply]

104,765,165, from US Census Bureau figures rather than the rounded off ones in the Wikipedia article. SpinningSpark 02:07, 7 December 2009 (UTC)[reply]

Any place with a coastline will have a somewhat indeterminate exact area because of the fractal nature of the coastline - so going to that degree of precision is probably too much anyway. SteveBaker (talk) 02:59, 7 December 2009 (UTC)[reply]

The fractal nature of the coastline causes a problem for determining the length of the coast but not so much for the area enclosed. The USCB quotes the figure in square miles to two decimal places, so they must think they have it nailed to within a handful of acres. The precision I have used roughly corresponds to the precision the source has used and I am sure we can take the USCB as being expert in these matters. SpinningSpark 03:47, 7 December 2009 (UTC)[reply]

The difference between the two answers is 0.0002%. I would imagine that is well within the difference of the size of the state between high-tide and low-tide, so SteveBaker's answer is sort of correct; it probably isn't the fractal nature of the coastlines, its that the actual size of the state is fluctuating, and the amount of that fluctuation is larger than the difference between these two measurements. That wouldn't necessarily apply to a state like Colorado, however differences is measuring the land area may also arise. For example, the land area may be calculated from a map projection in one or both cases, and EVERY single map projection will introduce errors, just differing amounts. Plus, does one or both calculations assume a perfectly flat topography, or are they taking changes in elevation into account? --Jayron32 03:57, 7 December 2009 (UTC)[reply]

Out of curiosity, I did the math. The coast of California is at least 850 miles long (much greater including small bays and inlets), and the difference between the two figures given is 275 acres. Along an 850-mile coast, we can lose 275 acres of land surface by submerging a bit less than three feet of coastline. Neat. TenOfAllTrades(talk) 04:28, 7 December 2009 (UTC)[reply]

Which would be a very small difference in tides, so QED. Of course, that still does not answer if we replace California with Colorado, which being bordered by straight lines and not having a coastline, should have no variability in its area. But, as I said, different methodologies will result in different measurements of land area. However, with Colorado, there is likely to be a really correct answer due to the nature of its boundaries, which is different from California. --Jayron32 04:38, 7 December 2009 (UTC)[reply]

These calculated areas assume that all hills have been squashed flat to sea level (on some projection). In reality, the land area will be much greater (if you had to spray it, for example) when slopes are taken into account. Are there any calculations of the actual 3-D surface area? It shouldn't be too difficult to get an approximation with modern GPS technology. Obviously the answer would depend on the resolution, but a reasonable compromise might be to take a height measurement every few yards to avoid counting areas of small rocks and molehills. Perhaps the calculation would make a bigger difference where I live (northern UK) where most of the cultivated land is on a slope. Dbfirs 08:59, 7 December 2009 (UTC)[reply]

The USCB says of the accuracy of its data;

The accuracy of any area measurement data is limited by the accuracy inherent in (1) the location and shape of the various boundary information in the TIGER^® database, (2) the location and shapes of the shorelines of water bodies in that database, and (3) rounding affecting the last digit in all operations that compute and/or sum the area measurements.

Ultimately, this database takes its geographic information from US Geological Survey data. The USGS define the coastline as the mean high water line, so no, California is not changing its area on a daily basis with the tides. It does of course, change over time due to such things as erosion, deposition and changing sea levels. SpinningSpark 13:43, 7 December 2009 (UTC)[reply]

Argh! Where do I start?

The reason I invoked "fractals" was precisely because I assumed that the USGS would use the mean high water mark or some other well-defined standard for tidal extent. The area of a fractal may be just as unknowable as the length. The length is not just unknowable - but also unbounded (in a true mathematical fractal, the length is typically infinite). The error in calculating the area can be bounded (eg by measuring the convex hull of the water and of the land and calculating the exact area between them) - but the actual area is only known for some mathematical fractals. For example, we know the exact area of a koch snowflake - but we don't know what the true area of the Mandelbrot set is [26]) - and we certainly don't have an answer for "natural" fractals. If you have to measure the coastline accurate to within (according to TenOfAllTrades) three feet - then the fractal nature of having to carefully measure around the edge of every large rock of every crinkly little tidal inlet (to a precision of three feet!?!) ensures that your error will easily be a few hundred acres.

This is why SpinningSpark and Jayron32 are both incorrect and TenOfAllTrades calculation (while interesting) isn't what matters here.

To Dbfirs - GPS technology doesn't help you at all unless you are prepared to clamber over the entire state logging GPS numbers every few feet...and that's not gonna happen. GPS is irrelevent here. (If you wanted reasonably accurate height data for California, you'd probably use the NASA radar study they did with the Space Shuttle a few years ago.)

As for measuring the 3D area of the land instead of a projection - please note that mountains are also fractal. The area of a true 3D fractal is typically infinite just as the length of a 2D fractal is infinite. (See: How Long Is the Coast of Britain? Statistical Self-Similarity and Fractional Dimension). A mountain is a 3D fractal - a coastline is only a 2D fractal - but the problem is exactly the same. Do you include the surface area of every boulder? Every little rock and pebble? The area of every grain of sand on the beach? Do you measure area down to the atomic scale? Where do you draw the line?

So - you have to use the projected area - that's your only rational choice - and the fractal nature of the coastline prevents you from getting an accurate measure (certainly not down to a precision of a couple of hundred acres). Since we're told they USGS uses the TIGER dataese - I'm not at all surprised that there are errors because that data is a pretty crude vector outline of coastlines. That dataset was primarily drawn up for census purposes - it was never intended to be an accurate description of the shape of coastlines. SteveBaker (talk) 14:30, 7 December 2009 (UTC)[reply]

The bigger question is does it really matter. The purpose of measuring area and boundaries to extreme accuracy is basically property rights: i.e. this land is mine, delineated from your land by this line. The state charges property taxes based on so-and-so dollars per acre, etc. So the real calculation of the real area of an entire state, while intellectually interesting, is practically trivial. Even for defining things like borders within bodies of water, and water rights; these are established by treaty and law, and these treaties and laws often include "fudge factors" for erosion and the like. The rules which define U.S. state borders around the Mississippi River, for example, include stipulations which allow for both slow erosion of river banks; in this case, the border drifts with the river, so states along the Mississippi have differing areas every day. If the river "abandons" an old channel and forges a new channel (i.e. oxbow lake formation); in that case the border does NOT change with the river, which explains why there are some locations in states along the Mississippi which are on the "wrong" side of the river, c.f. Kaskaskia, Illinois. Yes, any calculations are going to be approximations, but civil authorities cannot live with the "mathematicians" solution which says "its all fractals, and unboundable, so there is no definite answer". There always exists a set of error bars which is both workable in civil society, and which eliminates the fractalness of the problem. --Jayron32 16:19, 7 December 2009 (UTC)[reply]

You're right of course - this 0.0002% error is entirely unimportant. If anything both the Wikipedia number and the US Census Bureau number should be rounded off to the nearest thousand acres or so - and both groups should be chastised for using an unreasonable amount of precision! The only interesting point here is what the size and cause of the error truly is - and hence how much rounding should be applied. SteveBaker (talk) 16:43, 7 December 2009 (UTC)[reply]

Wikipedia cannot be faulted for quoting data to the same precision used by our sources. To round off numbers because of some supposed fractal "smearing" would be original research on our part unless the sources themselves also say this is happening. SpinningSpark 18:14, 7 December 2009 (UTC)[reply]

The discrepancy is suspiciously close to the difference between the international foot and the U.S. survey foot, or international acres and U.S. survey acres.—eric 18:59, 7 December 2009 (UTC)[reply]

You might be suspicious but I think you should show some good faith. The discrepancy is due to what I said it is in my first post, that is, a rounding error, both figures are ultimately from the same source in the same units. As far as I know, there is no such thing as an international acre, but if there were, it would be 1/640th of an international mile squared and the discrepancy would be 4ppm, not 2ppm. SpinningSpark 00:45, 8 December 2009 (UTC)[reply]

... and since the area measured the old way with a surveyor's chain would be significantly greater (because of slopes), the slight inaccuracy in a theoretical projected area doesn't really matter. Thanks SteveBaker, I should have said satellite survey, since GPSatellites only transmit (except for correction data). I was thinking of GoogleEarth where heights are given (or estimated?) every few yards. In the UK, we could use Ordnance Survey data which is surprisingly detailed on height. I agree that there is no one correct answer for 3-D area, which is why I said average every few yards, but there is no "correct" way to do this, so it will probably never be done. Projection area depends on the projection applied to the calculation. Steve suggests rounding to the nearest thousand acres, and that sounds reasonable in view of the inherent inaccuracies. Do we have any experts on projections who could estimate the differences in the area estimated using different projections? Dbfirs 20:04, 7 December 2009 (UTC)[reply]

Well, I've spent a large fraction of my career worrying about map projections (I used to work in flight simulation). Really, the only reasonable projection in the era of computers is to project onto the mean sea level WGS-84 spheroid. That's the internationally recognized standard for the shape of the planet - it's what GPS uses. I don't know what other projections would make sense - certainly not the flat-earth versions. If the survey pre-dated WGS-84 (which was established in 1984) then probably it would have used an earlier definition for the shape of the planet - maybe the Clarke spheroid of 1886. Calculating the error between the two is do-able - but it's way more work than I'm signing up for! SteveBaker (talk) 04:03, 8 December 2009 (UTC)[reply]

You are confused about a few things, the World Geodetic System does not specify a map projection. See also: Datum (geodesy)#Reference datums, Datum (geodesy)#Vertical datums, reference ellipsoid, geoid, mean sea level, etc.—eric 18:55, 8 December 2009 (UTC)[reply]

Thank you to both of you for the links. They've given me lots to read and think about. I've been puzzled about the difference between map areas and real areas for nearly fifty years! ( If mean sea level rises with global warming, will all calculated areas have to be increased? Yes, I know that one metre in 4 million is only 0.000025%, and that's only about a 0.00005% increase in area. ) ;-)Dbfirs 10:05, 9 December 2009 (UTC)[reply]

beef slaughter house

A friend touring a beef slaughter house said he saw cows walking into an open horizontal barrel one at a time and when the gate was closed the cow inside the barrel started shaking violently until a man put a hammer handle like device between the cows ears to kill it. He said the violent shaking was because the cow knew it was going to be killed. Is this true or is there some other explanation? 71.100.160.161 (talk) 23:42, 6 December 2009 (UTC) [reply]

There are procedures used in some slaughterhouses where cattle, once they enter the stunning box are electrically stunned using tongs or other devices before the use of a captive bolt pistol and then ejected for exsanguination. Nanonic (talk) 00:06, 7 December 2009 (UTC)[reply]

The cattle have been under severe stress since they were loaded onto the truck back at the farm, not much attention is paid to comforting cows on the way to slaughter. The natural response of a cow to any sort of confinement or other stress is to run away from it (but not too far, they're herd animals). When the cow goes into the killing box, it's being confined to very close to zero movement, this is essential to get a clean kill. For the cow though, it's now gone from severe stress to ultra-maximum stress and its body will react accordingly. However to say the cow "knows" it is going to be killed, to me imparts rather more self-awareness than a cow actually possesses. They are sensing a dangerous situation and responding instinctively. Franamax (talk) 02:00, 7 December 2009 (UTC)[reply]

I wonder whether the cow was shaking because of the electrical stunning? Electric shock can cause muscle tremors. If so, it wouldn't have been conscious at the time. SteveBaker (talk) 02:50, 7 December 2009 (UTC)[reply]

No, he says it walked into the barrel and did not start shaking until the gate was closed. The front part of the barrel obscured everything but the head and it was not until 5 or 10 seconds later when the operator waled up on a platform and administered the (I presume) shock. 71.100.160.161 (talk) 03:37, 7 December 2009 (UTC) [reply]

Nope, the cow doesn't know that closing a gate behind it means it is now going to be killed. What it does know is that it can no longer back up ergo it can no longer move at all - this is my maximum stress scenario. If you're going to confine a cow, you have to be sure the pen has higher sidebars than the cow, else it might try to jump over. Think of this from the POV of the cow, everything that has happened to it today has been bad and now it's getting worse. You can throw down some nice alfalfa hay in front of a cow in a pasture field and very calmly shoot it in the head (believe me). The cow is just panicking from the general situation. Franamax (talk) 04:16, 7 December 2009 (UTC)[reply]

The problem with that scenario, which is why the first is used, is transporting hundreds of pounds of meat from the field to the slaughterhouse, which is expensive. If you killed every cow in an open field, then paid somebody to drag it onto a truck, then transported the dead carcass to the abattoir, it would be a) very expensive and b) less sanitary due to the amount of time the dead meat isn't being processed appropriately. If you actually kill the cow at the slaughterhouse, you get to prep the meat almost instantly after death (which is more sanitary) and the cow basically walks himself to his own death, saving LOTS of money and labor. If you find this method of death to be immoral in some way, then you may not want to eat cow. If this doesn't really bother you, then feel free to eat the cow. --Jayron32 04:56, 7 December 2009 (UTC)[reply]

You may be interested in the work of Temple Grandin to reduce the anxiety of cattle in the slaughterhouse. -- Coneslayer (talk) 13:48, 7 December 2009 (UTC)[reply]

Since we can't ask the cow's opinion the question is moot. Cuddlyable3 (talk) 11:21, 7 December 2009 (UTC)[reply]

Sure we can. The answer is moot. --Stephan Schulz (talk) 12:02, 7 December 2009 (UTC)[reply]

It's a moo point. -- Coneslayer (talk) 13:48, 7 December 2009 (UTC)[reply]

Stephan just made that joke. --Tango (talk) 17:20, 7 December 2009 (UTC)[reply]

MOOray COWristmas. Cuddlyable3 (talk) 21:49, 7 December 2009 (UTC)[reply]

Wikipedia:Reference desk/Archives/Science/2009 December 6