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September 3

Power Plant Efficiency

Consider a power plant running on petroleum. The fuel has a certain amount of chemical energy and it produces a certain amount of electrical energy. How would I find an estimate for its efficiency? (It doesn't have to be very accurate, I just want to compare it to the efficiency of a car's engine... which I also haven't estimated yet. All I've got so far is the thermodynamic efficiency based on temperature of the furnace versus ambient temperature and I don't think that is going to be a good estimate.) Thank you. RJFJR (talk) 00:32, 3 September 2013 (UTC)

Typical diesel engine generator sets run at about 42 to 45% overall thermodynamic efficiency. You can verify this by going to manufacturer's or dealer's websites (eg Caterpillar) and downloading data sheets for any model of your choice. This applies over the range for small portable gensets to huge power stations. Coal fired and oil fired steam turbine power stations run at somewhat less efficiency, especially older power stations, but the fuel (coal or heavy bunker oil) is much cheaper.

Typical gasoline car engines run at around 22 to 27% thermodynamic efficiency at best throttle setting. Diesel engines in power generation service are considerably more efficient than car engines because 1) they operate at higher compression ratios (typically 15:1 vs 9:1), they do not thottle the intake air, and because they operate at a constant RPM, the design can be optimised for that RPM. Also, turbo charging, which can only be applied to a limitted extent set by detonation on a gasoline engine, can be applied to a diesel engine to a much larger degree limitted only by mechanical and thermal stresses. By recovering heat energy from the exhaust and putting it to use, turbocharging raises thermodynamic efficiency as well as power output. A minor factor: The combustion temperatures in a gasoline engine are higher, especially at part throttle, because the combustion is stochiometric. A diesel engine operates with excess air. The higher combustion temperatures in gasoline engines mean a higher proportion of heat lost to the coolant, lowering efficiency.

On light loads, the efficiency of a diesel engine falls off not as bad as it does for a gasoline engine (because the intake air is not throttled, and because combustion tempertures go down).

However, if a large gasoline engine is designed to run only at a specific optimum RPM, no expense is spared, and is operated by trained personell, its efficiency can approach that of a diesel engine. For example Word War 2 vintage Merlin and Pratt & Witney aircraft engines.

58.170.175.173 (talk) 01:41, 3 September 2013 (UTC)

45% efficiency for a diesel generator sounds high, but are you only looking as far as the output terminals of the generator, and neglecting losses in transformers and transmission and distribution? Edison (talk) 02:16, 3 September 2013 (UTC)

Correct, the figure applies only to the extent of the generator terminals. Losses in transmission and distribution can be any sort of value and I assumed the OP didn't want it included. For example, a genset in use at a mine site will have only simple local distribution, and distribution losses may be only 1% or less. But a municipal power station feeding a state-wide grid will encounter transmission and dustribution losses very much greater. For this reason, electric automobiles recharged from the electricity mains are rarely a global carbon advantage, even though their internal efficiency may be 90% or better, or 80% if you include the losses in the charger. For the figure for gasoline engines I gave, it applies to to mechnical output at the flywheel, and does not include losses in the gearbox and differential. 58.170.175.173 (talk) 02:29, 3 September 2013 (UTC)

Yes, I always cringe when I hear somebody claim that electric cars are pollution free. It's unlikely they have a solar or wind source for the electricity, more likely they are burning coal, with all the pollution that creates. It's similar to how people who buy a baked chicken don't seem to think they are responsible for that animal's death. StuRat (talk) 08:19, 3 September 2013 (UTC)

And even if they do have photovoltaic power, over the lifetime of the car and the solar panels, you should include the energy used to make the solar panels, which is quite substantial, and generally coming from coal fired power stations. Those solar power greenie freaks definitely belong to the same club as your baked chicken friends.1.122.244.100 (talk) 08:34, 3 September 2013 (UTC)

That depends very much on where they are driving (or at least, charging). If they are driving in France, then virtually none is from coal. (About 75% is from nuclear – and I don't think it's useful to repeat the debate about nuclear here – and about half the remainder comes from hydroelectric and other renewables.) If they are driving in Canada, then about 13% is from coal (all fossil fuels together make up about 20% of the electricity mix); nearly two thirds (63%) comes from hydroelectricity. If they are driving in Iceland, then nothing comes from coal, and 99.9% comes from a completely renewable mix of hydroelectric and geothermal power. Not every country in the world is the United States or China. And if one can persuade one's government to be responsible in its choices for new and replacement power plant construction, the electric vehicle can become 'greener' over time—something that can't happen with a fossil-fuel vehicle. TenOfAllTrades(talk) 13:22, 3 September 2013 (UTC)

Regarding hydropower, few countries are lucky enough to use this as a major source. Regarding nuclear, leaving aside the debate about accident safety and waste storage risks, which is largely political/emotional, the problem is economics. For instance, various Australian State power authorities, especially NSW and WA, looked seriously into nuclear power in the 1960's and 1970's. The trouble is, when amortising the costs over the life of the power station and waste management facilities, you need a power station so huge, one power station generates more power than the entire market, or it just isn't economic. The West Australian power authority got creative, and looked at buying essentially a US submarine engine room - that was small enough, albiet not able in standard form to meet civilian land locked radiation leakage standards, but they still coudn't make it pay. So no Australian state went ahead with it. Countries like France, USA, and Japan are fortunate in having a population and thus power market much larger and able to make it pay. In the case of the USA, Britain, and France, making bomb fuel as a "sideline" helps justify the nuclear industry. 1.122.244.100 (talk) 15:59, 3 September 2013 (UTC)

That's a false claim. "Making it pay" depends entirely on how you tax the waste products. The nuclear industry is expected to include the cost of total, 100% cleanup of all of its operating waste and decommissioning costs into the price of the electricity. If the coal/oil/gas powered power plants were required to do the exact same thing (implying capturing 100% of the CO2 and scrubbing out the acid-rain-causing materials - and also returning slag heaps, open-cast mines, water retention dams and flattened mountains to usable land, preventing damage to water tables and earthquakes from fracking and so forth) then they'd be completely priced out of the market and nuclear would look cheap by comparison.

If we had invented nuclear before coal powered plants, there is no way that coal would be able to enter the electricity market. It's purely an historical accident that we allow one industry to do more or less what the heck they like while the other has to be regulated out the wazoo.

SteveBaker (talk) 16:28, 3 September 2013 (UTC)

Indeed, and then you also have the fine dust emissions from coal fired powerstations and from cars with combustion engines which kill large numbers of people. So, while one worries about big nuclear accidents, the largest recent one the Fukushima disaster in which zero people died, worldwide hundreds of thousands of people die prematurely each year from lung diseases made worse by air polution. Count Iblis (talk) 01:19, 4 September 2013 (UTC)

Quibble: If you are going to count premature deaths caused by air pollution in the case of coal, then you also need to count premature deaths due to radiation exposure in the case of nuclear plants. Since many of the emergency workers were exposed to high levels of radiation in Fukushima, presumably some will die sooner than they otherwise would have. I do agree that coal pollution kills more people than nuclear plant emissions, though. StuRat (talk) 07:35, 4 September 2013 (UTC)

Chernobyl caused 31 deaths immediately and added a 2% to risk of cancer for a few thousand more. 10 children died from thyroid cancer and 700 more were affected by it - perhaps 4,000 people will die prematurely (but mostly not VERY prematurely) because of the fallout.

But that's comparable to the 30 deaths per year amongst coal miners in the USA and 4,000 new cases of "black lung" each year in coal mine workers - a quarter of whom will die prematurely because of it. Figures on the number of people who die from shipping the coal and at the power plant itself are not available - but they aren't zero. People outside of the immediate workforce have also died from landslides in the spoil tips (Aberfan disaster for example - where the children of an entire village were engulfed and died) and from waste water dams failing (The Buffalo Creek Flood, for example - where 125 civilians died).

The huge difference is that the mine-workers and people living near to coal mines suffer this death toll every single year - and we most certainly don't have accidents on the scale of Chernobyl even once per decade - so far we've really only had two within first 50 years of the industry.

Worse still, comparing US mining death rates (US coal mines are probably the safest in the world) with a Russian nuclear accident isn't fair. The Chinese death toll due to below-ground mining accidents alone is over 6,000 per year...and the Fukushima accident has yet to kill a single person.

But in any case, the world has more than enough people - but we only have just one atmosphere. SteveBaker (talk) 14:24, 4 September 2013 (UTC)

It is misleading to claim that radiation/nuclear contamination from the nuclear accident at Fukushima resulted in zero deaths. That is the official weasel claim of the Japanese Government, and presumably the source of Steve's incorrect claim that Fukushima has yet to kill a single person. But their culture has embedded a marked tendency to avoid or distort inconvenient truths. And this claim is true in its words but totally misleading. There hasn't been enough time yet for such deaths to show up - it can take 10 to 20 years or more. An article in the Japan Times describes a study done on deaths among elderly residents evacuated from the radiation hazard zone. The size of this zone means that almost all such evacuated residents were not evacuated because of the tsunmai damage alone. The study looked at 328 residents - a very small sample of those elderly residents evacuated. Of these, 75 died, whereas statistically only 28 should have died between the Fukushima event and the study cutoff in March 2013. It is not suggested they died from radiation. The trauma of forced evacuation and a reducion in living standards and quality of life is what did it - but there are still ~47 deaths that would not have occurred had Fukushima not been a nuclear power station. Since only a small sample population was studied, we can reasonably infer that the true figure could be in the thousands. See Mizuo Aoki, Elderly 3/11 nuke evacuee deaths spiked, Japan Times, English Language version, March 28, 2013.

Also, there were news reports of nursing home and hospital patients dying after being left in situ without food or medical care due to hospital staff clearing out thinking that someone from their equivalent of civil defence will come within a short time, and they could also return themselves. Due to chaos and communication mix ups no-one did come in time for some patients.

Apart from the deaths that have resulted from the nuclear accident (not to be confused with deaths due to the tsunami that would have occured even if the power station never existed), you should take into account the impact on vast numbers of Japanese. I happened to visit the doctor a few weeks after the Fukushima event. It was evident that one of the nurses was Japanese. I asked her, just being friendly, if her folks back in Japan were ok. She burst into tears! Crying, she explained that she had just, after several weeks, managed to get her parents on the phone that day. They did not live in the hazard zone and were not evacuated. But their lives were totally disrupted due to power cuts and loss of employment (factories had shut down to conserve power). You just don't get that kind of thing with coal and oil fired power stations.

I do however agree that more deaths are associated with the routine operation of coal fired power stations than with nuclear power stations even when nuclear accidents are counted.

1.122.56.214 (talk) 07:43, 5 September 2013 (UTC)

(unindent) Yes, that's quite possibly true - but even thousands of extra cancer deaths in a once-in-a-couple-of-decades event like Fukushima are tiny compared to the number of affected coal miners.

Another consideration is that global warming itself is causing extra deaths. It seems incredible but a WHO report says that more than 150,000 deaths are caused every year by climate change. If that's true then switching over to nuclear energy would be a winning strategy - even if there were 100 Fukushima/Chernobyl-scale events every year.

SteveBaker (talk) 16:47, 5 September 2013 (UTC)

Scanimation

I'd like to make an article on this.

I don't think it's the same as Scanimate, but maybe is similar to Parallax barrier. It may have another name. Does this article exist already? Are there enough sources? Thoughts and suggestions would be most welcome. Thanks, Anna Frodesiak (talk) 02:42, 3 September 2013 (UTC)

Definitely not Scanimate. I think it is only similar to Parallax barrier in that only certain parts of the horizontal row of the image are seen (but sequenced in time rather than for one or the other eye). This trick is conventional animation with parts of successive frames interlaced and then selectively displayed by the sliding grid-card. Closer maybe to Lenticular printing, except using a screen to control which part is seen rather than diffeent angles around a lens (and relying on visual processing to "fill in the blanks" where the screen is blocking out the image entirely). DMacks (talk) 02:58, 3 September 2013 (UTC)

Your brain is at least 4 times bigger than mine. :) Okay, Lenticular printing is maybe a see also item. So, the next thing is about whether or not it can stand on it's own two feet as an article, or should be a section somewhere. And the other thing is about sufficient sources. Anything non-spammy is about the video scanimate. Thoughts? Anna Frodesiak (talk) 03:12, 3 September 2013 (UTC)

I would call it a Moiré_pattern animation. /slit animation/ also gets several relevant hits on Google, and that search also led me to Zoetrope. So I guess it's a Moiré Zoetrope :) SemanticMantis (talk) 03:25, 3 September 2013 (UTC)

It's not Moire because that implies that the lines in the image and the foreground object are not parallel - and that's not the case here. (And it's definitely nothing to do with Scanimate). It's really just a flattened out Zoetrope. The video says that it's an "optical illusion" - but it isn't that either. It's nothing more than a three frame movie. The images contain three frames of animation (the least you can get away with to generate unambiguous rotation directions) - with the three frames interleaved. The overlaid screen just selects one of the three frames to view while occluding the other two. Nothing particularly special about it. SteveBaker (talk) 16:09, 3 September 2013 (UTC)

US Patent 7151541 is the mother ship, associated with several published books/toys using it (see patents citing it, and work up the tree; there you also have the inventor's name if this item is notable). DMacks (talk) 03:36, 3 September 2013 (UTC)

I think this deserves a small section at Moiré_pattern but not a separate article. Does that sound right? Anna Frodesiak (talk) 05:14, 3 September 2013 (UTC)

For what it's worth, that sounds good to me. It's a very interesting trick, but probably doesn't warrant a whole article. You could ref the patent, and perhaps one of the books that uses it. SemanticMantis (talk) 14:47, 3 September 2013 (UTC)

I disagree. This is nothing whatever to do with Morie fringes. That implies that the two sets of lines (in the image and the overlay sheet) are at some angle to one-another - and they aren't (or at least don't have to be) for this effect to work. SteveBaker (talk) 16:09, 3 September 2013 (UTC)

It has the similarity of using a striped screen moved across another image, with the effect of creating an animation, wherein the perceived image seems to move. In the classic Moiré pattern, the underlying image is usually a regular geometric pattern. This case is not the same as the classic demonstration, in that the underlying image need not be regular or repeating. So, while it not be a Moiré pattern under some (nonexistent) strict definition, that is the closest place. There may be other choices, but nobody has yet made a case for a better place to include information on this technique. SemanticMantis (talk) 16:17, 3 September 2013 (UTC)

Zoetrope already has information about "linear zoetropes" (and the Masstransiscope!) - which are precisely what this is. Putting the information into the Moire article confuses and muddies what that is all about (which is interference patterns). The whole idea of an encyclopedia isn't to just wedge the information in there someplace to avoid "losing" it - but to carefully consider where it belongs. SteveBaker (talk) 18:19, 3 September 2013 (UTC)

I suppose this thing could be added to Zoetrope. But the video linked by the OP is not a linear Zoetrope. In a Zoetrope, each "frame" of the image is viewable on its own, as a complete image. In the OP's video (and the patent, etc), the screen is necessary to fill in the gaps. That is, the "image" underneath doesn't make any sense without the screen. As far as I can tell, that is not the way the masstransiscope works either. It looks to me that in the masstransiscope, each frame is a full image, and the slits just control which image you see at which time. Maybe we do need a new article after all! SemanticMantis (talk) 18:47, 3 September 2013 (UTC)

And here's [1] a picture of the Masstransicope frames. As you can see, they don't require a screen to complete (and also mask) the image, as our current device does. SemanticMantis (talk) 18:53, 3 September 2013 (UTC)

I suppose you have a point about the multiple slits...but it's still nothing remotely to do with Moire fringes. SteveBaker (talk) 19:01, 3 September 2013 (UTC)

Nothing remotely? Have a look at Shape_moiré :) I see no substantive difference between the animations there, and the video that the OP links. Contrary to what you seem to think, moiré patterns aren't required to be made from parallel lines, or even be geometrically regular. It is a generally-used term to describe how the combination of two different layers can occlude and interfere, and give rise to a new pattern that was not present in either layer alone. But, thanks for this discussion, it forced me to dig deeper into WP, and learn a few new things (they apparently use this type of "shape" moiré in marine navigation, to make arrows that change direction, and always point toward the obstacle (our ref at Moiré pattern is sadly broken))! And there's no reason we can't have links to zoetrope and other related concepts. SemanticMantis (talk) 19:44, 3 September 2013 (UTC)

Yep! Nothing remotely. That article you linked to is indeed related to moire fringing - it's resampling the data at a different frequency...not at all the same thing as the animation technique referred to here - even though it appears superficially similar. Mathematically, it's not remotely the same...I'm sorry if you don't understand the distinction - but it's truly not the same. SteveBaker (talk) 20:29, 3 September 2013 (UTC)

You really think the animations at shape moiré and the what the OP linked are completely different? The video the OP links could also be described as sampling at different spatial frequencies, with the phase controlled by position of the screen. Both there, and at shape moiré, we have a striped screen moved across an image. In both cases, the filtering out of some frequencies allows a different image to be seen, that is partially made up of bands from the screen, and partially made up of the underlying image. When the screen is moved, the combined image appears to move, due to changes in phase. For me, that is more than enough similarity to consider them the same, for the purposes of WP classification. The only difference I can see is that, in shape moiré, the underlying image is periodic in one direction. So, if your argument is that, to be a "true" moiré pattern, the base layer has to be periodic in one direction, then I can concede that difference, even if I don't agree with the definition. I As for the rest of the math, you are aware that all the math on our articles is ad-hoc, and developed to illustrate how specific examples work out, right? There is no canonical set of equations that can in general model any given moiré pattern. The whole notion of moiré patterns is a bit subjective, so I suppose it's a bit pointless to argue about what does and doesn't qualify. Still, if you care to show us what you mean by "Mathematically, it's not remotely the same", I'll be all ears (er... eyes :) SemanticMantis (talk) 20:57, 3 September 2013 (UTC)

So what's the verdict? Shall I stub it and see how it develops? Anna Frodesiak (talk) 12:43, 4 September 2013 (UTC)

Your call. Thanks for the interesting post! I tried to explain my perspective as clearly as I could, and in my view, it's a sub-class of a wide variety of moiré patterns. It could go in a section at the main article, or as a stub, maybe moiré animation. I actually only skimmed the patent, maybe there's a better name there? Also, if you can find info on any of the books that use they patent, they may call it something specific like "magic screen" or something. If so, that would be a good redirect. I'm traveling for a few days, but I can work on it next week if you contact me on my talk page with the stub link. SemanticMantis (talk) 14:33, 4 September 2013 (UTC)

Okay, I went with Moiré pattern#Animation. I had absolutely no idea how to describe it. It's an eleven on the horribly-written scale. Anna Frodesiak (talk) 23:55, 4 September 2013 (UTC)

I also usurped this former redirect to Scanimate, and made it into a dab page: Scanimation. I'm not sure if I got it right. Anna Frodesiak (talk) 00:15, 5 September 2013 (UTC)

Teabags and Toothaches

Upfront: I do not have a toothache and am not looking for medical advice, just curious about a folk remedy that I can't seem to find a discussion of. I've seen/heard that if you put a tea bag in your mouth, over a tooth that is infected, that it will draw out the infection- I've heard a number of variations too: it has to be a black tea, needs to be warm and wet, needs to be dry, etc.. At any rate, no matter how much I look, I've never come across anyone debunking this claim, or even discussing it beyond the recommendation, most other common folk remedies are debated/discussed elsewhere. So, does this work and, if so, by what mechanism, and if not, why does it seem to get a free pass. (Note: I'm sleepy and wording poorly, I don't mean to suggest that I think it works because nobody debunked it- I doubt it would do anything but give you a foul taste in your mouth.)Phoenixia1177 (talk) 10:09, 3 September 2013 (UTC)

I would consider that "treatment" a Poultice - "used to treat abscess wounds, where a build-up of pus needs to be drawn out." Also, the caffeine may bring some pain relief. http://www.telegraph.co.uk/news/uknews/1360756/Why-a-cup-of-tea-can-ease-the-pain.html. I personally have never heard of this remedy. 196.214.78.114 (talk) 10:48, 3 September 2013 (UTC)

I'd suggest that one reason this hasn't been aggressively debunked is that, unlike many old wives tales, it's not that old. Many old wives have been around for longer than tea bags. HiLo48 (talk) 11:02, 3 September 2013 (UTC)

(JK) They'd be really really old. At least 110. Teabag#History (Lacks citations.) 196.214.78.114 (talk) 12:29, 3 September 2013 (UTC)

Although not in popular use in the UK until the 1970s (purely my personal recollection but I'm fairly certain). Alansplodge (talk) 12:43, 3 September 2013 (UTC)

FWIW I remember Tetley teabags being available in the UK in the mid-1960s. According to this page they sold 5000 tonnes of them in 1968. AndrewWTaylor (talk) 14:36, 3 September 2013 (UTC)

Well I stand a little corrected, however "In the early 1960s, tea bags made up less than 3 per cent of the British market, but this has been growing steadily ever since. By 2007 tea bags made up a phenomenal 96 per cent of the British market..." [2] This page says that we use 130,000 tons of tea per annum, so assuming a similar consumtion in the 1960s, 5,000 tons would be nearly 4%. Alansplodge (talk) 20:14, 3 September 2013 (UTC)

There could be other interpretations of the story or your question, but I'm taking the brass-tacks question here to be: does Camellia sinensis interfere with damage to teeth by Streptococcus mutans? Looking these two things up online, it looks like this is a question pursued by good students around the world, and classes have actually done some good work with it, summarizing the literature and testing on their own. [3] [4] (though the notion of schoolkids growing up isolates of decay-causing bacteria is slightly worrisome...) The latter experiment makes it clear that ordinary mouthwash is generally more potent against bacteria in vitro, but that first student wiki puts forward an interesting hypothesis that tea catechins could have another effect in toxin secretion. Searching NCBI turns up a number of similar studies from throughout the Middle East. [5] My feeling is that the practice is based in science, but the effectiveness of this specific procedure, or little variations in it, has not really been demonstrated. Wnt (talk) 13:54, 3 September 2013 (UTC)

The reason that these things are not always well debunked (or even shown to be true) is that it takes no more than 20 seconds for someone to come up with a semi-plausible idea like this. Let's say: "Soaking your feet in warm diet cherry coke every night before bedtime is a sure-fire cure for male pattern baldness"...that only took me 10 seconds to think up - and I could spam it to the world and a bunch of people would repeat it as truth...before you know it, it would be on The Dr. Oz Show. But it takes years of careful and expensive scientific study with hundreds of human test subjects to show whether it's true or not. It follows that most of these "old wives tales" will go forever untested.

Imagine a test for the teabag hypothesis. You'd need to take 100 people with toothache and have a third of them use the teabag, another third use placebo bag filled with inert, fake, tea-leaves and another third do nothing. Wait for a week and have them all examined for signs of infection. This is kinda unethical - that's 100 people who really should have seen a dentist who didn't. With all of the statistical work, the coming up with a really good placebo bag, double-blinding the experimenters, crunching the numbers, deciding whether there might be something in it - which might require some follow-up work, and publication - with more people duplicating your experiment to verify the results...the whole thing might easily cost a half million dollars to run just to debunk the myth.

So you cannot use the lack of a complete debunking as some kind of evidence that something fairly obscure like this is untrue.

NOTE: Neither this author nor the WikiMedia foundation either promote or endorse soaking your feet in warm diet soda of any kind - do so at your own risk! :-)

SteveBaker (talk) 15:51, 3 September 2013 (UTC)

The difference though is that folk remedies generally spread when they are found to be effective by a user. Of course, they can spread for wrong reasons - political salesmanship like for the King's evil (though some pricey meat wouldn't hurt there), mnemonic convenience like for the doctrine of signatures. They can also spread because they have some sensible science behind them... even though they don't actually work! But not infrequently they spread because they do work. The world is full of traditional medicines that actually contain useful compounds. It is useful in such instances to keep an open mind either way, neither saying yes nor no as a default. Even placebo is sometimes prescribed by physicians, so why discourage using something with a chance? Wnt (talk) 16:41, 3 September 2013 (UTC)

But most folk remedies don't work - and things like Homeopathy spread like wildfire despite that. Some folk remedies are really dangerous - such as Rasa shastra which purports to cure diseases with helpful metals like mercury and lead - that didn't stop it from becoming popular. Others that are growing in popularity in the US include gold and silver therapies - which can cause Chrysiasis and Argyria. All it takes is for some random idiot to read that silver has antimicrobial properties and to extrapolate from this true fact to the entirely unwarranted conclusion that consuming colloidal silver will cure what ails you - and you may soon find that your skin turns permenantly and irreversably purple. SteveBaker (talk) 18:14, 3 September 2013 (UTC)

The problem is in what "found to be effective" really means. With a single self-diagnosing patient, self-prescribing a preferred folk remedy, there's a whole bunch of problems. It's a condition where straight up placebo effect should be expected to be strong (often bolstered by a good bit of spurious argument from authority, whether from grandma, the internet, or a fringe publisher who mistakenly believes that sharks are immune to cancer). There's also the post hoc ergo propter hoc problem—a lot of symptoms targeted by home remedies will go away (or lessen, or be perceived to lessen) by themselves, purely by time or chance. It's an almost ideal incubator for random psychological reinforcement. TenOfAllTrades(talk) 20:34, 3 September 2013 (UTC)

Homeopathy and colloidal silver aren't folk remedies - they're well promoted modern scams with organized backing, and in the case of the former, formal legal authority to offer "diagnoses" and "medications" and "treatments" not allowed to the average wise-woman. Of course, I recognize that there are plenty of ideas from traditional medicines that are completely wrong, but it doesn't deserve credit for these. (Traditional medicine tends to be particularly good for purposes such as immediate pain relief where the user knows whether a clove or a beaver testicle helped his toothache or not a minute later; and particularly bad at long-term uses like for cancer treatment (I don't remember seeing a single traditional treatment for cancer that worked, and they actually missed treatments like yew bark that they had in their pharmacopoeias) Wnt (talk) 22:25, 3 September 2013 (UTC)

I picked those two examples precisely because they are popular enough to have been carefully tested, so we know for sure whether they are effective or not and can therefore discuss them rationally. Things that a very few people believe are not gonna get carefully examined (for the reasons I explained above) so it's hard to find examples of major screwups. But there is no particular reason to assume that an untested treatment from a modern scammer is any more or less effective than something from the proverbial "old wife". Without research, either one of them could be effective, ineffective, provoke a placebo reaction or could be downright dangerous.

The idea that sticking a clove against a painful tooth will make the pain go away might work well for one person but badly for another. It could have nasty side-effects - maybe the tooth falls out three months after treatment or the patient gets a fatal form of cancer ten years down the line because of it. How would anyone notice that the clove was the problem? Without using modern research methods, you have no idea what you're really doing to the patient - even if it seems to work every time. SteveBaker (talk) 13:33, 4 September 2013 (UTC)

OK - how about this as an example. 20 years ago, grapefruit was a "herbal remedy" for all sorts of maladies. It actually did seem to work - but modern science has since discovered that what's really going on is that this fruit interacts with all sorts of biochemical mechanisms and has truly horrendous drug-interaction effects - magnifying the potential of otherwise harmless doses of other chemicals to do serious damage. (See Grapefruit–drug interactions). If your grandma tells you that grapefruit is good for your allergies - and you happen to take it within an hour of taking some Benadryl...well, let's just say "Don't Do That!". SteveBaker (talk) 13:44, 4 September 2013 (UTC)

It's hard to use this as an example - it didn't seem to be mentioned by Dioscorides or Pliny... after a bit I looked up grapefruit and found it was an 18th-century hybrid. Culpeper's herbal doesn't seem to include it either [6] Now, the first and foremost thing about genuine traditional folk medicine is that it is old - sometimes hundreds of years, often thousands, and the use of a few herbs may have even been shown to date all the way back to the Neanderthals. Now, if I take some other curious entry from Culpeper, say about "goutwort" (which I assume is aegopodium podagraria), well, I don't find much in NCBI but I do see it contains a fair amount of falcarindiol, a COX-1 inhibitor. [7] Now they call it "nutraceutical" Since that occurs in carrots also I suspect that is not the end of what might be found in such a plant (since gout sufferers don't usually extol the virtues of those), and certainly looking just now I didn't make much of an effort; but neither has science, I think. My point though is that I would have pretty high hopes for something from one of the old herbals, but not from a random magazine article that cobbles together some snippets of science to push a superfood. Wnt (talk) 07:30, 5 September 2013 (UTC)

molecular mass and formula mass

I need 5 differences between molecular mass and formula mass .... can anyone help me (139.190.171.116 (talk) 13:08, 3 September 2013 (UTC))

You can read our article on molecular mass (which also discusses formula mass) if you do not feel like, or are confused by, the materials provided by your teacher in class or as assigned for you to read in your textbook. Your teacher is obviously asking something based on what you are learning in class, so it's best for you to use its resources to give the answer the teacher wants. DMacks (talk) 13:24, 3 September 2013 (UTC)

I don't see the mass of the empirical formula (which is, according to google, the definition of formula mass) being mentioned in that article... Ssscienccce (talk) 14:25, 3 September 2013 (UTC)

Is why I softened my statement to focus on whatever terminology and ideas the teacher/textbook used. Without knowing what facts and definitions were given, we're stuck saying "google it, here's what I found" or "our formula mass is a redirect to molecular mass and we don't have a distinct definition according to a reliable source". Neither of those would earn passing marks. If there is a difference according to IUPAC, please add it with cite to the article. If this is just a fuzzy or obsolete distinction, then maybe it's best we don't propagate it at all. FWIW, there are bunches of google hits that formula mass is actually what it means in lay language: sum of masses of atoms in the "formula" (either molecular or not explicitly empirical). DMacks (talk) 14:33, 3 September 2013 (UTC)

Good to know the vagueness of the term wasn't just in my head. ;-) IP seems to originate from Pakistan, maybe it has a more precise definition in the original language... Ssscienccce (talk) 15:17, 3 September 2013 (UTC)

help identify this bug

Hi, can you please tell me what is this creature? found dead in Haifa, Israel

unknown bug

Thanks --Golan's mom (talk) 13:15, 3 September 2013 (UTC)

Upon further examination, I have observed the creature to be a member of a species of insect which may be found in parts of Israel, including Haifa. ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 13:29, 3 September 2013 (UTC)

Intelligence tells me that it is a bug-shaped bug manufactured by the Israeli government. Capable of storing 3.72 terabytes of info. ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 13:29, 3 September 2013 (UTC)

Please refrain from posting jokes, especially before the question has a legitimate answer. Nimur (talk) 14:40, 3 September 2013 (UTC)

Dubious humor aside, my wild guess is it looks like some species of longhorn beetle, but even if that's right it leaves a large field of possibilities... Wnt (talk) 13:58, 3 September 2013 (UTC)

Because of complex politics, Wikipedia's articles about nature, wildlife, and ecology in the Levant are particularly fragmented. I watched passively as our article currently known as Biodiversity in Israel, the West Bank, and the Gaza Strip changed hands between Fauna of Palestine and Fauna of Israel multiple times over the last few years. Personally, I was too embroiled in the war in South Lebanon for me to divert any of my encyclopedic energy to the more noble pursuit of natural science, Everyone suffers when senseless conflict erodes our ability to share and categorize our knowledge freely. Anyway, that page links to a few online databases that might be helpful, but I'm unable to reach any of the servers linked - they may be inoperable, or simply very slow. Still, despite the fragmentary organization, there are dozens of Palestine and Israel "lists of fauna" categories and lists that you can peruse by following the category links on the bottom of that page, e.g. Category:Environment of Israel and Category:Environment of Palestine.

Before we jump to wild guessing about the specimen, we should aim for the kind of procedural study that a proper entomologist would use. Here's a guide to arthropod morphology from the American Museum of Natural History that points out the key features that we should focus on, to aid in classification and taxonomy identification. For example, the lack of a visible external ootheca almost categorically rules out any type of cockroach.

With luck, one of our better bug enthusiasts can help us out narrowing down the species. Nimur (talk) 15:07, 3 September 2013 (UTC)

I appreciate your request to refrain from jokes. Refraining from soapboxing is also good advice. --Onorem (talk) 15:14, 3 September 2013 (UTC)

Sorry. I am attempting to sincerely express that our encyclopedia coverage of this topic is actually degraded by the ongoing political conflict, and despite my intimate familiarity with the region and its biodiversity, I am not able to find great internet links about the insects of Haifa. Nimur (talk) 15:18, 3 September 2013 (UTC)

I went to the MNH site suitably chastened, to see what the professional guide would recommend... actually, it links to a group of articles like this which says first to look at the wings, which we can't see, then "Basically, you're eyeballing your specimens, looking at the differences and similarities. Sort your specimens according to shape, color, number of legs, and any other differences you can discover ... If you are able, for example, sort all the things that appear to be beetles. Next separate the long, narrow beetles from the round beetles. Then take a closer look at the long, narrow beetles and see characteristics that some share, like the same type of antennae or the shape of their wing covers." Which actually more or less matches the ad hoc thought process I'd used here, so now I don't feel so bad. Still a poor substitute for a taxonomic key. But looking one up I get [8] saying that there is no accepted taxonomic key - besides, with no way to properly examine either the wings or the genitals, our possibilities are limited. Wnt (talk) 16:34, 3 September 2013 (UTC)

Additionally, we can rule out true bugs by the mouthparts, and see that there are complete elytra. Together, those suggest a beetle, and the long antennae make longhorn beetle a pretty good pick. Still, it is worth mentioning that very few insects can be identified to species level via a single photo, even with a key and training. SemanticMantis (talk) 16:54, 3 September 2013 (UTC)

Thank you for pointing me in the right direction - before I could just tell Golan that it's a bug ... Looking up the longhorn beetle in the English Wikipedia as well as in the in the Hebrew Wikipeida I have arrived at this great site with pictures of Cerambycidae of Israel, see here to insects of Israel. Thank you! --Golan's mom (talk) 17:59, 3 September 2013 (UTC)

And if I would have to take a guess, I would say that the closest to what we found would be Niphona-picticornis --Golan's mom (talk) 18:12, 3 September 2013 (UTC)

semi permiable membrane

semi permeable membrane (talking in context to osmosis) dont allow solvent molecules to pass through it even if the spm has pores of bit larger size than it is of the solute particles.

The fact mentioned is 100% authentic just i need a satisfactory explanation — Preceding unsigned comment added by Shubhamagrawal1996 (talk • contribs) 15:25, 3 September 2013 (UTC)

There are many biochemical mechanisms that exist to help explain how flow against a concentration gradient is possible; this includes selective permeability and active transport. I wonder how "pore size" is being defined... if we were using molecular physics terminology, we could talk about the atomic radii at the periphery of the pores, and we could describe active transport as a selective mechanism to open and close the pores by converting chemical energy (from adenosine triphosphate, usually) into other forms of molecular potential energy. That energy can be used to apply an electrostatic potential to the periphery of the pore, essentially altering the collisional cross section of the pore in a specific way for each solute molecule. As a physicist, I would now say "the pore aperture is smaller than the solute particle cross-section" - but as a biologist, I can see an equally coherent justification for saying "the pore aperture did not change size, but it no longer permits the solute to pass through it." Nimur (talk) 15:59, 3 September 2013 (UTC)

Biochemical? My interpretation of the question was membranes used in reverse osmosis, like for desalination of seawater. Haven't find an answer though. Reading the question again, I see it says not allowing solvent molecules to pass, not sure if that is what he means, in that case nothing passes?Ssscienccce (talk) 22:55, 3 September 2013 (UTC)

Biology

When there is acidity, why the colour of urine become deep yellow?Is due to high level of urochrome? — Preceding unsigned comment added by Titunsam (talk • contribs) 17:26, 3 September 2013 (UTC)

I don't know the answer, but here are a couple related observations:

1) When I drink lots of water, my urine is clear, presumably because it is quite dilute. This would also tend to make it less acidic.

2) When I take lots of vitamin C (ascorbic acid), my urine is bright yellow. StuRat (talk) 07:26, 4 September 2013 (UTC)

Osmosis, diabetes mellitus, and osmosis

Pick the correct answer to the following question. Write a brief statement explaining why each choice of answers is correct or incorrect.

In diabetes mellitus, because of insufficient insulin production, glucose cannot enter cells. instead it accumulates in the blood plasma. which of the following statements would be true under these conditions?

A. The concentration of the plasma would decrease. B. the osmotic pressure of the plasma would remain the same. C. Water would move out of the tissues into the plasma. D. Tissue cells would swell. — Preceding unsigned comment added by 98.214.102.79 (talk) 17:46, 3 September 2013 (UTC)

Or E. Do you own homework. 82.21.7.184 (talk) 18:23, 3 September 2013 (UTC)

You may want to read the article Osmotic Pressure, as well as Tonicity. Knowledge of those concepts should be sufficient to answer at least B-C. I'm not quite sure how to answer A, as the phrase "concentration of the plasma" is vague and confusing. -- 205.175.124.72 (talk) 00:52, 4 September 2013 (UTC)

The speed of light versus the speed of sound. Which has more for the buck?

Years ago a did an experiment utilizing two multiple speed tape recorders. I read the entire front page of the local newspaper on one recorder, rewound it then replayed, put it on the fastest speed to re-record it. I repeated that process three times. Lo and behold the entire paper was a mere BEEP. That being said leads to the question if you could speed it up say a hundred times it might be possible to fit the entire library of congress into a mere beep? If the science is there/here maybe those beeps I've heard that certain astronomers are listening to,,, actually mean something? Origiman (talk) 21:12, 3 September 2013 (UTC)

Your experiment with tape recorders was employing Lossy compression. Many of the people involved with SETI have PHD's in information technology and related fields. Surely they examine their data with every known compression algorithm in mind.--Digrpat (talk) 22:35, 3 September 2013 (UTC)

Speaking of which, using quantum computing with superposition of states, how much information can you put into a single photon shot out into space? Wnt (talk) 23:03, 3 September 2013 (UTC)

You can store a lot of information in the momentum of the photon, the total amount depends on the distance between transmitter and receiver. This follows from the total number of available quantum satates in a volume V; for a single photon this is 2 V W/h^3, where W is the volume in momentum space, the factor 2 is the spin degree of freedom. To measure the photon momentum with an accuracy delta P requires the measurement apparatus to have a size of hbar/(2 Delta p), so the more information is stored in the photon momentum, the larger the detector needs to be to extract that information. And then we've not taken into account the noise that one has to average out. Count Iblis (talk) 23:27, 3 September 2013 (UTC)

I read that this is actually a problem for SETI, because an ideal compression algorithm renders data indistinguishable from white noise. If we assume that any sufficiently advanced civilization actually encrypts and compresses its communication, which is not a stretch, it makes it very unlikely that we'll even recognize the signal as "intelligent", let alone figure out what anything in the signal means. Vespine (talk) 23:34, 3 September 2013 (UTC)

That is in fact a real conundrum. A similar conundrum existed during the cold war: SIGINT, the interception of enemy signals, was a persistent topic of very advanced research. In many cases, the order to launch (or not launch) nuclear missiles was intentionally meant to appear as white noise, and transmitted at all times, because any other type of signal broadcast to the numerous submarines that were necessarily dispersed across the entire globe would clearly indicate the plan to strike (or equivalently, the absence of a command not to strike). I am still astonished that we survived so many decades without more accidental nuclear launches. The existence of these radio signals may seem like fringe-theory pseudoscience, until you build your own very-long-wavelength, extremely low frequency radio and hear the constant, droning, almost-tonal hissing that's always hovering just below the very-well-studied completely natural noise floor. Nimur (talk) 00:37, 4 September 2013 (UTC)

I doubt it's really that much of a problem for SETI, because SETI isn't likely to be able to detect anything that's not shot pretty directly at us in a narrow beam. Why an ET civilization would go to the trouble to do that, and then encrypt it so we couldn't understand it or even distinguish it from noise, would need explanation. --Trovatore (talk) 02:13, 4 September 2013 (UTC)

I inherited a fantastic book, formerly owned by Ronald Bracewell, called The Search for Life In the Universe, by Goldsmith and Owen (from UC Berkeley and SUNY Stony Brook). It is an excellent, very rigorously scientific analysis of this problem. There are two entire chapters on the motivation and practicality of using photons to encode information, including a brief section on the encoding of meaningful information as "bits" stored among the various physical properties of the photon (using the terminology of 1980-era physics and information theory, which is still pretty current, and I'm happy to say is totally bereft of the more recently popular term "qubit"). Anyway, anybody who is interested in squishing lots of information into a radio photon may find this book an interesting read - whether your goals are the academic pursuit of SETI or if you are more involved in the more worldly engineering practicalities of optical or radio communication. Nimur (talk) 14:38, 4 September 2013 (UTC)

This is not, as suggested above, "lossy compression" per se. That is, there is no theoretical issue with compressing audio like this indefinitely. You're just frequency shifting the data up into increasingly high frequencies, and frequencies can potentially rise infinitely high. To that end, you can in principle encode the whole Library of Congress into a single sub-second audio pulse. Where the problems enter is in practical engineering -- no real device will handle those absurdly high frequencies, and so you won't be able to losslessly reverse the process. CDs, for instance, are engineered for about 22 kHz signals. Any signal above that frequency is fundamentally unidentifiable (and any digital implementation will share a similar hard upper bound). Analog equipment doesn't have that hard ceiling, but practical tolerances will still impose themselves before the audio compression idea gets very far. The end result, then, resembles lossy compression (because you certainly have lost data), but it shouldn't be confused with what is meant by "lossy compression", where even in the ideal case data is voluntarily destroyed. — Lomn 01:43, 4 September 2013 (UTC)

Agree with your analysis with a small quibble. The process as described is not just frequency-shifting; rather the time compression leads to frequency expansion. For example, if the original sound occupied frequency range 20Hz-20kHz,after being recorded at twice the speed, the signal will occupy frequency range 40Hz-40KHz. Thus the analog tape used to record the speeded up sound (and the equipment used to record/read the sound) will require higher physical tolerances to maintain fidelity, as you say. Abecedare (talk) 02:41, 4 September 2013 (UTC)

That's the real issue here. If you had an utterly perfect tape recorder - you could do what the OP suggests without loss. But there is no possibility of ever building anything that perfect. All practical tape recorders (and voice recorders of any kind) have limited bandwidth and limited dynamic range - so at every recording, some of the speeded up information is too high in frequency for the tape recorder to record. When you slow down one of those 2x speeded up recordings to retrieve the original text, it'll sound muddy - when you slow down the 4x, 8x and 16x recordings, that'll get worse and worse - to the point where you won't be able to understand what's said anymore. SteveBaker (talk) 13:23, 4 September 2013 (UTC)

September 4

Question about atomic repulsion.

If electrons are what repulse atoms, what happens if the atom has no electrons? Sincerly, camerontregan^talk 08:02, 4 September 2013 (UTC)

Then the positive charge of the naked nucleus would cause the atoms to be repulsed; or if you believe that the free neutron stands in as element number zero, then a neutron gas would be near impossible to contain, as temperatures anything higher than a few pico-Kelvin, it would simply diffuse through the walls of any containment vessel. Plasmic Physics (talk) 08:31, 4 September 2013 (UTC)

In a neutron star, that's what happens. Without the repulsive force of the electrons, the material collapses in on itself. If there is enough mass, you get a black hole - but for more sane objects, you'd get a solid material. An effect called quantum degeneracy pressure stops it from collapsing any further - and that's due to the Pauli exclusion principle which basically (very basically) stops identical things from being at the same place. SteveBaker (talk) 16:05, 4 September 2013 (UTC)

Given that neutron stars will only form with huge (at terrestrial scale, and still pretty damn big in stellar terms) masses, and still involve some slightly odd physics, I think "sane" is a bit of an overstatement. MChesterMC (talk) 08:52, 5 September 2013 (UTC)

There is no need to invoke neutron stars, just try enriched californium. It readily outgases neutronium gas. Plasmic Physics (talk) 09:28, 5 September 2013 (UTC)

Flat feet

Is there any situation where flat feet/fallen arches would be an advantage? Thanks ツ Jenova20 ^(email) 10:21, 4 September 2013 (UTC)

Yes. You would be rightfully exempt from most physical exercises, e.g. running, because the lack of friction between the feet and the ground for you would be unfair so that's that. That is, if your flat feet were that serious. ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 10:40, 4 September 2013 (UTC)

Back in World Wars I and II, it could have gotten you out of army service. Nowadays, it appears that "flat feet are perfectly functional and may even be an advantage in sports", and among US Army recruits, the flat-footed suffer fewer training injuries than those with high arches, according to the New York Times article "The Maligned Flat Foot: Some See an Advantage". Clarityfiend (talk) 12:20, 4 September 2013 (UTC)

That's strange...I'd always heard the opposite, that flat feet affected balance, carrying loads, walking distances, and increased injuries overall, disqualifying people from the army. Thanks ツ Jenova20 ^(email) 12:55, 4 September 2013 (UTC)

A lot of the problem for the army back when that was an issue was that they only had one design of boot - and it didn't suit flat-footed people. Since they did a lot of marching around back then - it was a huge issue. (Sorry - I don't recall where I read that). SteveBaker (talk) 13:18, 4 September 2013 (UTC)

Perhaps you read it in our amazingly-well-cited section on toe anatomy and physiology, which references U.S. Army studies of comparative foot sizes - including the seminal post-war work, "Foot Dimensions of Soldiers" (1946) that distilled all knowledge learned about flat-footed American GIs of the second World War? It's almost encyclopedic, the amount of information available here!' Nimur (talk) 14:51, 4 September 2013 (UTC)

On a related topic, is this the top view of the left foot, or the under view of the right foot? The article toe anatomy and physiology says right...Thanks ツ Jenova20 ^(email) 16:23, 4 September 2013 (UTC)

The caption is correct; Plate 269 is the plantar view of of the right foot ("looking up"). There's a little bit of symmetry, and the uninitiated might easily confuse it with a top-view of the left foot; but you can verify a few easy features: the navicular bone is on the insole and is visible; the calcaneus (heel) is plainly visible. You can see the diagram has labeled the plantar (bottom) attachments for the flexor tendons, but not the extensors; (and you know which direction toes flex on a healthy human's foot - they curl downward, hopefully!) Plate 268 is the dorsal ("top") foot surface; compare the visible extensors, the talus bone (ankle); and so on. Nimur (talk) 20:38, 4 September 2013 (UTC)

Thanks for clearing that up ツ Jenova20 ^(email) 08:47, 5 September 2013 (UTC)

My father found his lat feet an advantage in that they exempted him from the US military draft. μηδείς (talk) 00:54, 7 September 2013 (UTC)

Projects that cannot complete during the life of the people who started it.

We were talking (above) about a space mission to the nearest star...how it would certainly take hundreds of years to get there.

This made me think about the problem that whoever designed and launched this hypothetical probe - and (importantly) whoever came up with the funding for it - would never see their project do much more than disappear from our solar system.

This makes be think that it would be very hard to get funding for a long-term project that would produce no results until after everyone who had anything to do with it was dead.

Are there any projects like that underway right now that will eventually come to a definite conclusion - but not within the lifespan of anyone who was involved with making it happen? I'm having a hard time thinking of even a single one!

SteveBaker (talk) 18:08, 4 September 2013 (UTC)

Not a science project, but John Cage's As Slow as Possible is currently being performed in Halberstadt, Germany, and that will last until around 2640. More scientifically, one of the motivations for archiving astronomical data, including data from crappy old photographic plates, is to permit detection of changes that occur over long periods of time. This is, however, not a concrete experiment with a definite expected conclusion. --Wrongfilter (talk) 18:23, 4 September 2013 (UTC)

A while ago someone here mentioned Beal's seed germination experiment [9]. Currently running; the guy who started it is long dead. Several other candidates at that "longest running experiment" thread from a few months ago. SemanticMantis (talk) 18:38, 4 September 2013 (UTC)

Yes - but both of those examples produce benefits to the instigator from day one. I'm trying to come up with something where the original people who started the project have to do it entirely altruistically because they know for sure that they won't live long enough to see any of the results. SteveBaker (talk) 18:58, 4 September 2013 (UTC)

The Cologne Cathedral was started in 1248, suspended in 1473, and finally completed in 1880. The first usable part (AFAIK) was consecrated in 1322, 74 years after construction started. The people who constructed it may, of course, have drawn spiritual satisfaction from the mere act of building. --Stephan Schulz (talk) 19:07, 4 September 2013 (UTC)

That's a good one actually. I wonder if the people who started it expected to see it finished in their lifetimes? Of course, they probably expected to get credit for kicking it off once they made it to heaven...so perhaps this wasn't a truly altruistic effort. SteveBaker (talk) 20:33, 4 September 2013 (UTC)

(reply to Steve) I don't think your assumption that the originators will not "see any of the results" is right, because surely any project like sending a probe to a star will have many (1) technical (eg testing that different propulsion and communication technologies work), and (2) secondary goals (such as making observations of the solar system and its surroundings on the way). In fact, any such project will inevitably consist of a series of probes over decades to test and refine different sub-systems, and practically speaking individuals will be devoting their careers to designing specific features of those various probes, with only the larger "institution" (hopefully) surviving to see the project to completion. Compare say with the Apollo program, in which "land a man on the moon" served as a large motivating goal, but individual engineers and groups were perhaps only trying to wheedle out 2% power from the Saturn rockets, or make the space helmet look cooler. Ditto, for the current Mars probes, which have the motivating goal of finding life on Mars/sending a manned mission to Mars. Or, if one were to get poetic/philosophical, physics, which has the motivating goal of "explaining" all natural phenomenon.

The point being: the fact that one won't see the end of a larger project in ones lifetime/career, doesn't mean that one won't get any results, and a measurable sense of achievement, in that lifetime. Abecedare (talk) 19:28, 4 September 2013 (UTC)

You might be right - if this hypothetical space probe was gathering data along the way - then it wouldn't be a total bust for the people involved.

I also wonder whether this is the solution to the Fermi paradox. Alien species aren't talking to us because each individual knows that he (she/it?) won't get a response within their lifetimes - so it's not worth the effort of talking to us when that money could be better spent on gold-plated antennae and tentacle polishers. SteveBaker (talk) 20:33, 4 September 2013 (UTC)

Well, there is the Voyager Golden Record, which will certainly not reach any aliens in the lifetime of the team that assembled it. But, as with a cathedral, just the act of assembling and sending it is a powerful statement to the current generation. --Stephan Schulz (talk) 21:25, 4 September 2013 (UTC)

Why doesn't Wikipedia provide medical advice?

moved to talk page μηδείς (talk) 18:53, 6 September 2013 (UTC)

what hormone is responsible for the facial fat sexual dimorphism in prepubertal children?

Is it progesterone or some form of progestin? Estrone or estriol? 64.134.65.22 (talk) 19:09, 4 September 2013 (UTC)

I mean, girls have more facial fat at 6-8 yo, way before puberty. Is this due to adrenarche? 64.134.65.22 (talk) 19:10, 4 September 2013 (UTC)

Ionized water - is there any truth to this claim?

Hi. I recently came across this article detailing an Irish technology involving treating water with nitrogen that supposedly increases yields by up to 30%. I find it a bit suspect because of its fantastic claims and the fact that none of the people mentioned have Wikipedia articles. Is there any truth to the science behind the claim? Thanks. ~AH1 ^(discuss!) 19:24, 4 September 2013 (UTC)

Well, the technology is bullshit, and bullshit is good as a fertilizer, so the technology must be good as a fertilizer due to the transitivity of the subset operation. No, seriously, if you apply electromagnetic radiation to water, you'll warm the water up a bit, and you might electrolyze a bit of it into hydrogen and oxygen gasses which will then bubble out of the water (see Photocatalytic water splitting), but neither of those is going to have any significant effect on plants that are watered with that water. Red Act (talk) 20:06, 4 September 2013 (UTC)

I guarantee it's bullshit. Magical "energized" water...hell no! If they'd made just one, narrow claim - it might have been credible - but when they start piling claim upon claim, it's clear that this is a ridiculous scam. It's remotely possible that this process produces a tiny amount of nitrates - but if it's using only "pennies" of electricity to process "thousands of gallons of water" then it's not going to be enough to matter. Electricity costs in Limerick (Ireland) are about 10 pence per kilowatt hour. So let's allow that this tiny box can put that much electrical energy in to chemical conversion of water and nitrogen into hydrogen and nitrates. How much nitrate would that be when diluted into a few thousand gallons of water? Nitrogen is very hard to break apart - it takes a lot of energy. Sadly, I don't see an easy way to calculate how much could possibly be converted...we need a chemistry expert here. SteveBaker (talk) 20:24, 4 September 2013 (UTC)

"Professor Austin Darragh says, 'Vi-Aqua makes water wetter...'." Nothing to add at the moment, I just liked that line :) Someguy1221 (talk) 20:35, 4 September 2013 (UTC)

I recall some stuff used in model railroading that was alleged to "make water wetter". What it actually did was interfere with water's tendency to form a surface "skin", which is especially noticeable on very small bodies of water. The stuff seemed to be something akin to soap, and was certainly not something I felt like ingesting. But everybody trying to sell something has got a gimmick... especially when the product is a humbug. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:54, 4 September 2013 (UTC)

See Surfactant, incidentally. Tevildo (talk) 23:24, 4 September 2013 (UTC)

this is a very good site compiled by a real chemist which discusses the myriad of water "scams", including ionized water. Vespine (talk) 22:56, 4 September 2013 (UTC)

Agree this appears to be a scam. [10][11] Notable for appearing in a formerly respectable source. In concept the claim of using electricity, even radio to do nitrogen fixation is not plainly impossible; you want N2 + 3H2O -> 2NH3 + 1.5 O2. But the resulting highly alkaline ammonia water would not necessarily be appreciated by plants in a direct application. (Sort of interesting though, how much of potential pH difference hides in the choice of which major atmospheric gas the hydrogen attaches to) In any case, there is the not insignificant problem that in reality doing industrial nitrogen fixation is not easy, nor do radio waves have anywhere near the energy difference one expects to see unless you have practically mystical catalysis going on. Wnt (talk) 02:01, 5 September 2013 (UTC)

They are claiming to achieve complete nitrification, not just fixation. So that would be nitrate, not ammonia. Someguy1221 (talk) 02:16, 5 September 2013 (UTC)

So I calculated it out. The conversion of nitrogen to aquous nitric acid costs 18kj/mol (it's surprisingly small because a nitrate ion does not have too much more energy than a nitrogen molecule, although this is a multistep process with rather significant thermodynamic barriers). If we assume perfect effeciency, which is assuming a lot, it would take 5000kj of energy to get an amount of nitrate containing 1kg of nitrogen. If we assume a kilowatt-hour costs 10 cents, then this actually only costs 14 cents per kilogram. To buy an equivalent amount of nitrate fertilizer from wholesale providers would cost about $6 (you have to place an order for tens of metric tons to get that kind of a discount, though). So their hope has merit, but I sincerely doubt that these guys managed to beat the fertlizer industry to the tune of 4300% relative efficiency, 15 years ago, and have yet to receive serious interest from independent scientists or businesspeople (who have been looking for easy ways to perform these reactions for over 100 years, by the way). Someguy1221 (talk) 02:46, 5 September 2013 (UTC)

That's odd... come to think of it, if you're content to get pure nitrate and neutralize it with some kind of cheap alkali, why can't you get the theoretical efficiency? I would have imagined that with a sufficiently contorted set of winding tubing forming a countercurrent exchange that you could bring N2+O2 to a temperature where equilibrium is favorable to nitrogen oxides and back again with little loss. The resulting smoggy mixture, bubbled up through water, ought to leave behind nitrous and nitric acid. Wnt (talk) 06:55, 5 September 2013 (UTC)

Because it's never favored. The closest thing to what you describe is the Birkeland–Eyde process, which has only a 4% yield at 3000^oC, and is extremely inefficient in terms of energy consumption. Someguy1221 (talk) 07:07, 5 September 2013 (UTC)

And bear in mind that this thing is the size of a biscuit tin (let's say, less than 1 cubic foot) and can continuously cope with the flow from a garden hose! SteveBaker (talk) 16:34, 5 September 2013 (UTC)

You do realize that in 50 years a hobbyist doing tabletop microfluidics is going to look through these archives and implement stuff like this as a lark? He may even present you with a working model. :) Wnt (talk) 23:53, 5 September 2013 (UTC)

In 50 years, I'll be 108 years old...I very much doubt anyone will be presenting me with anything! SteveBaker (talk) 12:54, 6 September 2013 (UTC)

You never know. What I do know is that your odds of being hale and healthy then are a lot better than your odds of winning the lottery, and there are people who play it anyway (though I'd never accuse you of such gullibility!) Wnt (talk) 19:44, 6 September 2013 (UTC)

why the veins blood is dark more than arteries blood?

Why the blood of the veins is dark comparing to the blood of the arteries? the reason connected to the oxygen? 95.35.210.39 (talk) 21:16, 4 September 2013 (UTC)

From having had blood drawn from both veins, it's pretty obvious that blood from veins is a darker, richer red. That stands to reason, as the veins are carrying various waste products from the cells. That might be another good reason to draw blood from veins rather than from the relatively pure arteries. The Blood article says (without citation) that veins' blood's blue appearance under the skin is an optical illusion. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:52, 4 September 2013 (UTC)

From blood, oxygenated blood is brighter than deoxygenated blood. "Hemoglobin is the principal determinant of the color of blood in vertebrates. Each molecule has four heme groups, and their interaction with various molecules alters the exact color. In vertebrates and other hemoglobin-using creatures, arterial blood and capillary blood are bright red, as oxygen imparts a strong red color to the heme group. Deoxygenated blood is a darker shade of red; this is present in veins, and can be seen during blood donation and when venous blood samples are taken." --Stephan Schulz (talk) 23:30, 4 September 2013 (UTC)

Schulz is correct. Heme is an uncommon and very powerful dye; there's nothing else in blood with anywhere near so much color. Other fun variations can be seen in blue Fugates, but here it's the strained ligand interaction with carbon dioxide rather than oxygen that matters.

The obvious problem with drawing blood from arteries is that they tend to be under pressure... Wnt (talk) 06:58, 5 September 2013 (UTC)

The blood from veins are dark in color because of the presence of "carbaminohemoglobin"(deoxygenated) , a respiratory pigment darker than "oxyhemoglobin"(oxygenated). Benison talk with me 16:28, 5 September 2013 (UTC)

Good point! We have an article on carbaminohemoglobin. I should explain the carbon dioxide actually binds to the hemoglobin protein rather than the heme; its binding and the increase in acidity from increased CO2 levels tend to release the oxygen. Methemoglobin is yet another variation, with the iron in a different oxidation state. Carboxyhemoglobin, in carbon monoxide poisoning, gives the blood a bright red color. I hadn't thought about the fact that oxygen and CO2 can be associated with hemoglobin at the same time, though not so happily: because the variations at the heme are what matter most, it isn't literally the binding of carbon dioxide that changes the color of the blood, but the loss of oxygen, unlike with carbon monoxide. Wnt (talk) 17:44, 5 September 2013 (UTC)

about taking blood test from the veins / arteries

What is the reason that we used to take the blood for a test from the veins and not from the arteries? Is there any biochemical reason or it's happen only because it's more easy to take from the veins? If we take a blood test from the arteries will it show us the same results? 95.35.210.39 (talk) 21:22, 4 September 2013 (UTC)

I'm sure there are many reasons. One of them will be evident if you ever have blood drawn from an artery: It hurts like hell, and you have to apply pressure for a while to prevent excess internal bleeding. Much less of an issue with veins. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:46, 4 September 2013 (UTC)

Veins are closer to the surface and thus easier to reach, are lower pressure, and have thinner walls. There may be other reasons too. Shadowjams (talk) 23:04, 4 September 2013 (UTC)

Arterial flow is harder to stop. μηδείς (talk) 00:11, 5 September 2013 (UTC)

In addition to reasons already stated (Arteries contain a muscular layer that makes it more painful to have blood drawn from them; risk of blood loss due to higher blood pressure; difficulty with bleeding; and accessibility) there is a risk of interrupting blood supply to vital tissue when an artery is punctured, and morbidity can result. In general, the expected results from venous and arterial blood are expected to be indistinguishable, with the exception of measurement of blood gasses, which is pretty much the only reason blood is routinely taken from arteries (partial pressures of arterial oxygen and carbon dioxide are clinically useful). There may also be instances in which arterial blood is used because it's easy for the physician to obtain (when veins are scarred or can't be accessed, or when there's an arterial line already in place, which is often the case in an ICU where a patient is on a respirator). - Nunh-huh 22:57, 5 September 2013 (UTC)

Something from nothing

Did space exist before the Big Bang? If nothing existed in it, then would it have been as infinite as it is now, or sufficiently tiny to accommodate the first particle. Is the size of space determined by the matter that fills it? russ (talk) —Preceding undated comment added 23:54, 4 September 2013 (UTC)

It's not clear whether "before the Big Bang" makes sense at all. You might get a better intuition if you mentally take the logarithm of the time after the big bang. That is, think of 1 second after the big bang as being as long after 0.1 sec as 0.1 sec is after 0.01 sec, which is the same interval as from 0.001 sec to 0.01 sec, and so on backwards. That moves the big bang itself to a point "infinitely far" in the past. --Trovatore (talk) 00:07, 5 September 2013 (UTC)

Oh, as to how that relates to your real question: If the universe is infinite now (which is an open question), then it always has been infinite, where "always" is to be understood in the sense above — that is, at any positive time after the big bang. If you extrapolate back to the big bang itself, then the distance between any two world lines goes to zero, so in that sense you would have just a single point at the big bang, but infinite space at any time afterwards. That's a strange-seeming discontinuity, but if the big bang itself "never happened" (that is, is infinitely far in the logarithm-of-the-past), then who cares? --Trovatore (talk) 00:10, 5 September 2013 (UTC)

The size and dimensions of what you call "space "is sape by what they call particles . Because actually the space content noting and endless . And for example when the particles are attracted by the gravity , they are attracted to it in power indefinitely at smallest size , so time flip dirction and multiplies the particl , so you got 3 dimension and it also depends on the strength of the attraction of the particles themselves . But again " space " made ​​of nothing and have infinity dimension and length . Thank water nosfim

Neither space nor time existed before the big bang. Space and time exist relative to measurable entities and changes (there is so much space between x and y, so much time elapses between this and that). Likewise, had the big bang occurred in space and time there would be a reason why it occurred now and not then, here and not there. The big bang is like the south pole. you can walk north from it, but there is nothing south of it. μηδείς (talk) 00:16, 5 September 2013 (UTC)

Time symmetric models have also been proposed like this one where the time evolution from the initial inflating patch is invariant under time reversal. So, we would then exist in both 13.7 billion year after and "before" the big bang, our copy on the other side of the big bang evolves backward in time relative to our positive time direction (but that copy will experience our negative time direction as his positive time direction). Count Iblis (talk) 00:25, 5 September 2013 (UTC)

We have Big_bang#Speculative_physics_beyond_the_Big_Bang_theory, which includes links to some theories. The answer is that no one knows. Stephen Hawking's theory is that the big bang was basically time zero, and there is no such thing as "before the big bang". There are many theories that posit some manner of universe existing before the big bang in which there may be space and time. All of them, except the ones postulating a universe that is infinitely old or cyclic, also have an issue with explaining "what came before". Someguy1221 (talk) 00:44, 5 September 2013 (UTC)

Roger Penrose - whose hobby sometimes seems to be betting against Hawking - has proposed and championed conformal cyclic cosmology. Gandalf61 (talk) 10:02, 5 September 2013 (UTC)

September 5

CTE

Have any studies been done on people other than sports participants or veterans to determine if they have had head trauma that it is CTE? — Preceding unsigned comment added by S0berpete (talk • contribs) 00:02, 5 September 2013 (UTC)

Chronic_traumatic_encephalopathy#Epidemiology also describes that people with a history of chronic seizures and domestic abuse victims are at a heightened risk of developing CTE. The reason that CTE research is so focused on combat veterans and athletes is that they are far far more likely to develop CTE - the first patient diagnosed was a boxer, for instance. This is a case study of five patients with CTE (back when it was called dementia pugilistica, or Boxer's Dementia). The patients included three athletes, a mentally disabled man with a history of banging his head against things, and an epilepsy patient with a history of smacking his head while falling during a seizure. Someguy1221 (talk) 00:53, 5 September 2013 (UTC)

Telescopes on the Moon

The Chang'e-3 is scheduled to launch in late 2013 and allegedly will carry a telescope for astral observations from the Moon. Will the Chinese be the first to attempt this or has another nation already done it? How does observation quality from the surface of the Moon compare to orbital platforms? Are there downsides? I couldn't find an article regarding telescopes on the Moon... DrewHeath (talk) 02:01, 5 September 2013 (UTC)

The Times of India thinks the first telescope on the Moon will be a private venture in 2016.[12] The MIT Technology Review has an article about using lunar dust to build a mirror.[13] There's also a proposal for a liquid mirror telescope.[14] Clarityfiend (talk) 02:48, 5 September 2013 (UTC)

Gastrobiology of obesity

Last month i believe there came a paper which suggests that Gut Flora play a role in the development of Obesity. Could you guys please elaborate In the simple and summerized way possible, why would Such a connection exists, and it's core principles in short?

Many many thanks for you kind help and illumination. 95.35.51.159 (talk) 02:28, 5 September 2013 (UTC)

This is a concept some have called Infectobesity. In summary, the idea is such: The bacteria in your gut play a huge role in the digestion and absorption of food that you have eaten. The obese have different gut flora than the thin. In particular, the gut flora often found in the obese allows their bodies to absorb a greater proportion of the energy from their meals than thin bodies are able to. The gut-flora differences do not apply to everyone: There are likely thin people with obesity-associated flora, and obese people with thinness-associated flora. It is unknown how broad this finding applies (i.e. does it vary with age, race geographic location, medical conditions, etc.). It is unknown whether having these gut flora makes you fat, or being fat causes your body to retain such flora. A paper came out earlier this year showing that you could cause mice to lose weight by altering their gut flora: [15]. Someguy1221 (talk) 03:06, 5 September 2013 (UTC)

Difference between char and charcoal?

Is there a difference between char and charcoal? The articles aren't clear, but they seem to define them in the same way. The biochar article seems to regard biochar as a specific type or application of charcoal.

So... they seem the same (so a merge might be needed) but I haven't found a definite answer from a reliable source.

(I see I'm not the first to ask.) --Chriswaterguy talk 02:44, 5 September 2013 (UTC)

One source about biochar and charcoal:

Christoph Steiner, a research scientist at the University of Georgia, says the difference between charcoal and biochar lies primarily in the end use. “Charcoal is a fuel, and biochar has a nonfuel use that makes carbon sequestration feasible,” he explains. “Otherwise there is no difference between charcoal carbon and biochar carbon.”

--Chriswaterguy talk 02:57, 5 September 2013 (UTC)

Wouldn't char contain a higher proportion of impurities such as phosphate and other minerals? Plasmic Physics (talk) 02:59, 6 September 2013 (UTC)

Why when the plane fly above the earth, are not affected by the movement of the Earth's rotation on its axis in other words, why not lengthen or shorten the distance between one country and another when it fly?

Why when the plane fly above the earth, are not affected by the movement of the Earth's rotation on its axis in other words, why not lengthen or shorten the distance between one country and another when it fly? why it's not affected it? — Preceding unsigned comment added by 37.238.50.113 (talk) 07:37, 5 September 2013 (UTC)

Because it's flying in air, and the air moves with the Earth. — kwami (talk) 08:31, 5 September 2013 (UTC)

In a sense, we do. Airflow ("wind" ;-) over the Earth is affected by Coriolis force, and modern air routes are very much designed to take prevailing wind patterns into account. Indeed, if you check North Atlantic Tracks, you will see that the optimal route configuration is determined every day, based on current meteorological information. --Stephan Schulz (talk) 09:44, 5 September 2013 (UTC)

But the direct answer to the question is that the plane is affected. However, what is affected is the steering, not how far it must travel. As Kwami said, the atmosphere moves with the Earth, and the distance the plane must fly is relative to the atmosphere. But as for steering, the airplane feels a force perpendicular to the Earth's axis — that is, partly horizontal and partly vertical. The horizontal component is called the Coriolis effect or Coriolis force, and the vertical component is called the Eötvös effect. But the Earth rotates very slowly — it takes a whole day to rotate a single turn — and the result is that the Coriolis and Eötvös effects are very small. A plane must be constantly steered in flight to overcome the effects of any crosswinds and up and down drafts; the Coriolis and Eötvös effects can easily be overcome the same way. And since they are not only small but almost constant during the flight, the pilot would not even notice them. --50.100.188.72 (talk) 10:11, 5 September 2013 (UTC)

Earth's rotation is however a significant factor in space launches. Escape velocity says: "as the Earth's rotational velocity is 465 m/s at the equator, a rocket launched tangentially from the Earth's equator to the east requires an initial velocity of about 10.735 km/s relative to Earth to escape whereas a rocket launched tangentially from the Earth's equator to the west requires an initial velocity of about 11.665 km/s relative to Earth". This has strongly influenced the chosen sites (to the south on the Northern Hemisphere) and direction (east) for most space launches. PrimeHunter (talk) 10:36, 5 September 2013 (UTC)

Yes, even if planes could fly above the rotating atmosphere, they would still take of with a speed (relative to an inertial frame fixed at the centre of the earth but not rotating with the earth) of the take-off ground-speed plus the instantaneous tangential speed of the airstrip. In the absence of air, and some (currently impossible) mechanism to counteract just gravity, the plane would continue at constant speed on a tangent to the curvature of the Earth. If you jump in the air, you tend to land again on the same spot, because the Earth has rotated under you , but you have (almost exactly) retained the tangential velocity of the spot you jumped from. In practice, it is usually simpler (for jumping, balloons, planes etc, but not for space launches) to ignore the rotation of the Earth and just to take into account winds and Coriolis forces. Dbfirs 13:03, 5 September 2013 (UTC)

Three leaves in a dicot plant. Is this a mutation?

Comparison of a monocot and dicot sprouting. Note that the visible part of the monocot plant (left) is actually the first true leaf produced from the meristem; the cotyledon itself remains within the seed. (Image is from our cotyledon article.)

I observed a plant of leguminase family that has three first leavs. I could see the two cotyldons, but the first leavs appared are in numbr three. I planted five seeds. All other four seeds produced two leaves each but this one seems very odd with 3 leaves. --G.Kiruthikan (talk) 10:53, 5 September 2013 (UTC)

Do you have a photo? Sfan00 IMG (talk) 13:45, 5 September 2013 (UTC)

It seems like a developmental anomaly, but probably not a mutation, although it could be. Identical twins in humans are also a developmental anomaly but not a result of a mutation. Looie496 (talk) 14:14, 5 September 2013 (UTC)

Do you mean conjoined twins ? StuRat (talk) 01:09, 6 September 2013 (UTC)

Without a photo there is no way to opine on this topic. We don't know what is meant by the leaves come in threes. Cannabis has leaves with an odd number of leaves--that doesn't disqualify it as a dicot. We need an image. μηδείς (talk) 01:31, 6 September 2013 (UTC)

The question makes perfect sense, but you have to know some basic plant biology to understand it. The great majority of flowering plants are either monocots or dicots. The defining feature of the two groups is that in monocots, when the seed sprouts, the stalk that comes up gives rise to a single tiny leaf; in dicots it splits into two tiny leaves. This is the defining feature, but there are many others that go along with it -- basically monocots are grasses and grasslike things, dicots are almost all the remaining flowering plants. The OP is saying that he saw a plant in the dicot group where the sprout produced three tiny leaves instead of the usual two. Looie496 (talk) 01:52, 6 September 2013 (UTC)

No tricots? Hmm Sfan00 IMG (talk) 18:05, 6 September 2013 (UTC)

The OP's "I could see the two cotyldons, but the first leavs appared are in numbr three" seems to imply that he is talking about the first proper leaves, not the dicotyledons, Looie. μηδείς (talk) 00:51, 7 September 2013 (UTC)

Eating shellfish during a red tide

Dinoflagellates of the genus Gonyaulax produce a toxin called "saxitoxin", which is concentrated in clams, mussels, and other shellfish that feed on these marine protozoa. During a red tide, they bloom, and eating shellfish during these times can be fatal due to unusually high concentration of the toxin. Now, is the fact that eating shellfish during a red tide is deadly ever related to the fact that Jews can't eat shellfish? Is there an anthropological basis for this dietary restriction? 164.107.102.52 (talk) 15:25, 5 September 2013 (UTC)

It's hard to know what's behind a two-thousand-year-old arbitrary religious rule - however, I'd guess that living in a hot climate, far from the ocean, in an era before refrigeration, would make not eating shellfish be an excellent rule...religious or not! SteveBaker (talk) 16:08, 5 September 2013 (UTC)

SteveBaker, you do realize that the restriction is written out in Deuteronomy, right? According to this source, some people think that Deuteronomy is written in approximately 600 BC. Under this dating, that would place it six hundred years more or less before Christ. From today, that's 2600 years. 164.107.102.52 (talk) 16:22, 5 September 2013 (UTC)

The way I always heard it, bottom feeders are considered "unclean", which is why not just shellfish, but also hogs and catfish are on the list. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:49, 5 September 2013 (UTC)

There's a rough hypothesis to be made that the ancient Israelites, living as a community in Egypt (which many historians will claim never happened) were in some way able to understand that a dangerous red tide was underway and created the first Passover as a way of ensuring everyone ate something other than shellfish. It's purely speculation. There might be something in this to that effect but only Google's secret index knows (I could drag out my crummy command line pdf2djvu and eventually get searchability but I can't be bothered right now) Wnt (talk) 18:12, 5 September 2013 (UTC)

Far as I know, Egyptian hieroglyphs make it reasonably clear that the Hebrews were there, except their spin on it was that they drove the Hebrews out. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:45, 5 September 2013 (UTC)

I took this one on in Wikipedia:Reference_desk/Archives/Humanities/2013_June_23#Where_did_Jews_come_from_before_the_Exodus.3F, left less than satisfied. Wnt (talk) 08:02, 6 September 2013 (UTC)

Makeshift electromagnet advice

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis, prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page.

This question has been removed. Per the reference desk guidelines, the reference desk is not an appropriate place to request medical, legal or other professional advice, including any kind of medical diagnosis or prognosis, or treatment recommendations. For such advice, please see a qualified professional. If you don't believe this is such a request, please explain what you meant to ask, either here or on the Reference Desk's talk page. --~~~~

Deleted means deleted Tevildo (talk) 22:31, 6 September 2013 (UTC)
The following discussion has been closed. Please do not modify it.
Sorry guys, but this is way over the line of what constitutes medical advice—whether the original poster insists that he won't hold us liable or not, encouraging him to build powerful magnets for use as a medical device will end badly for all involved. TenOfAllTrades(talk) 13:09, 6 September 2013 (UTC) Bullshit. My friend removed a splinter with a magnet from inside a hard drive. You jobsworths make me sick. --129.215.47.59 (talk) 14:45, 6 September 2013 (UTC)

What is the meaning of A1C?

I don't ask about the hemoglobin A1C (because I read about in our article on Wiki) but only about the meaning of the sign "A1C".what's the meaning? probably it's initials of something95.35.210.39 (talk) 19:30, 5 September 2013 (UTC)

According to our disambiguation page A1C, this probably refers to Glycated hemoglobin...but that page doesn't say what it means either. SteveBaker (talk) 19:55, 5 September 2013 (UTC)

If you look down the page, at some point it's written HbA_1c. So I suspect the answer is that it's a form of hemoglobin A, probably further subdivided into subtype 1 and sub-sub-type c. --Trovatore (talk) 19:59, 5 September 2013 (UTC)

There is an article on: Hemoglobin, alpha 1 (Hemoglobin A1). so, now we looking for the meaning of letter C. 95.35.210.39 (talk) 20:54, 5 September 2013 (UTC)

Why do you think there's a "meaning"? Is there any reason to think it's not just the next one classified after HbA_1a and HbA_1b? --Trovatore (talk) 20:56, 5 September 2013 (UTC)

I have not knew about HbA_1a and HbA_1b. It's not written on our article of hemoglobin, but the other are written there. I thought maybe it's a shortening of a any word. 95.35.210.39 (talk) 21:09, 5 September 2013 (UTC)

I don't know of them either; whether there's any such thing as HbA_1a or HbA_1b I couldn't tell you. It could be short for a word (HbF seems to be fetal hemoglobin; I don't know whether the F stands for "fetal" or whether it's just a coincidence). I just don't see any immediate reason to think it's likely that it stands for anything. But who knows; maybe someone will pop up and tell us. --Trovatore (talk) 21:13, 5 September 2013 (UTC)

It's possible that it once had an actual meaning - but has since become "what it's called". There are lots of things like that out there. Everyone knows what a "laser" is - nearly everyone has forgotten that it was once written "L.A.S.E.R: and stood for " Light Amplification by Stimulated Emission of Radiation" - even though that's no longer how all lasers work. In the end, it may not matter what A1C stands for - so long as everyone in the business of dealing with it agrees on what it is. SteveBaker (talk) 21:56, 5 September 2013 (UTC)

Wait, what? There are lasers that don't work by stimulated emission? Which ones, and how do they work then? --Trovatore (talk) 23:20, 5 September 2013 (UTC)

This is trackable, but if you want the answer it may take some work. For some idiotic reason I cannot begin to comprehend, even now NCBI's journal abstract indexes go back little further than they did 20 years ago. As far as I'm concerned they ought to be back to Hippocrates by now. The reference given in the article is one of the very earliest you get when you search hemoglobin a1c there and sort by date. You can follow authors on the study further - for example, to one amazingly quixotic but truly valiant attempt in 1950 to determine the point mutation in sickle cell hemoglobin, before the idea was understood, which alas came up with four amino acids possibly altered, but actually found less valine in what we now know is a E->V point mutation [16] hmmm but I digress. Anyway, it appears sometime between 1950 and 1964 the term was invented. If you want to find it for sure, I'd guess you should hoof down to the library and either (a) pull out those big nasty tomes of Biological Abstracts or (b) read some of the publications of WA Schroeder that NCBI indexes (but without abstracts) from the early 1960s. One of these available online [17] says HbA was named because it was "alkali labile". Some others such as [18] [19] might review it. Oh, anyway, my guess is that it is a variant seen with electrophoresis or perhaps column chromatography. Wnt (talk) 22:41, 5 September 2013 (UTC)

As Wnt correctly guessed, the terminology derives from ion-exchange chromatography. Kunkel and Wellenius, studying normal adult hemoglobin (hemoglobin A) in 1955, noted that there were "minor components" present that varied from the parent hemoglobin. Further study (Allen et al.) distinguished between five subfractions (hemoglobin A1a, hemoglobin A1b, hemoglobin A1c, hemoglobin A1d, and hemoglobin A1e), named in order of elution (all of these preceded hemoglobin A0, the main form of hemoglobin). They therefore called A1a, A1b, A1c, A1d, and A1e the "fast hemoglobins". Rahbar et al. demonstrated in 1969 that hemoglobin A1c was elevated in the RBCs of diabetics. In 1971, Trivelli et al. suggested that there was a relationship between hemoglobin A1c levels and long term complications in diabetics. More recently, the Committee on Nomenclature, Properties, and Units of the IFCC proposed a new term for HbA1c, namely Haemoglobin beta chain(Blood-N-(1-deoxyfructos-1-yl)haemoglobin beta chain; substance fraction), but as this is impractical in clinical use, "permits" the continuing use of the trivial name "HbA_1c".

(Kunkel HG, Wallenius G. New hemoglobins in normal adult blood. Science. 1955;122(3163):288)

(Allen DW, Schroeder WA, Balog J. Observations on the chromatographic heterogeneity of normal adult and fetal hemogloba study of the effects of crystallization and chromatography in the heterogeneity and isoleucine content. J Am Chem Soc. 1958;80(7):1628–1634.)

(Rahbar S, Blumenfeld O, Ranney HM. Studies of an unusual hemoglobin in patients with diabetes mellitus. Biochem Biophys Res Commun. 1969;36(5):838–843.)

(Trivelli LA, Ranney HM, Lai HT. Hemoglobin components in patients with diabetes mellitus. N Eng J Med. 1971;284(7):353–357.) - Nunh-huh 09:36, 6 September 2013 (UTC)

what is the meaning of "beta" on hormones

I saw some hormones with prefix "beta". now I remember only one "beta hcg", but I know that there are more. anyway, what is the meaning of this word ("beta") when it comes as prefix before an hormone name? 95.35.210.39 (talk) 19:36, 5 September 2013 (UTC)

See Protein subunit. Tevildo (talk) 19:59, 5 September 2013 (UTC)

In the case of Human Chorionic Gonadotropin, Tevildo's link explains the general concept, but you might also like to read the article about the hormone, which is a heterodimer composed of an alpha chain and a beta chain. The beta chain can also circulate as a monomer or a homodimer (see PMID 15192308). In other cases that come to mind (which are cytokines, but the boundary between cytokines and hormones is a bit fuzzy), a name was given to a chemical mediator thought to be a single substance, which later turned out to be a class of substances. Greek letters were added to differentiate between the different substances. See interferon. In the case of the interferons, the greek letter is sometimes written first ("gamma interferon"), but more often last ("interferon gamma"). In other cases (Transforming growth factor, Tumor necrosis factor, TNF), the Greek letter last-convention predominates. Interestingly, according to our article, TFNα has been renamed simply to TNF, and TNFβ to lymphotoxin alpha. Lymphotoxin alpha exists as a homotrimer, but may also form heterotrimers with yet another membrane-bound protein called lymphotoxin beta. So in this case, the greek letter does double duty, it differentiaties between completely different molecules, TNFα and TFNβ, and between different chains of the same molecule (lymphotoxin alpha and lymphotoxin beta when the protein is a hereotrimer).

A third and completely unrelated usage of greek letters preceding proteins, indicates the "band" a protein will migrate to in a serum protein electrophoresis. Examples: α1-antitrypsin, α2-macroglobulin. --NorwegianBlue ^talk 22:19, 5 September 2013 (UTC)

September 6

Microbes in fossil fuel reserves, fossil fuels ecologically important in place...

The ref desks are for asking questions, not for proposing theories. Looie496 (talk) 00:53, 6 September 2013 (UTC)

argument:: we are wrong about certain important aspects of ecology, both historically and presently. we are not crediting fossil fuels with their worth while underground. currently we state that it is un-important to the bio-sphere if we harvest fossil fuels, although pollution is damaging. I argue that indeed it is important to life both on the surface and underground that fossil fuels remain in place. claim: the recent discovery of microbial populations in deep hydrocarbon reserves should support the claim that there were microbial populations in shallow reserves. claim: The density and quality of hydrocarbons within a reserve affects the type and volume of microbial activity (although it is something I've considered that after getting what we can from a reserve, there might be a short term bloom given the newly found relaxed environment. hydrocarbons of high complexity can be broken again and again for energy) claim: Harvesting fossil fuels dramatically alters the subterranean environment, and therefore the biologic activity. claim: This affect in turn affects the surface. Hydrocarbon seepage is reduced with reduced reserve pressure. discussion: WE farmed and deforested nearly everything. We did a lot of replanting. the vegetation as it is today in nearly every location has changed 100% . Lots of things died on their own or were replaced by invasive species. actually, we can't ever know about invasive species of the time. If it's going on now, I would think it's ok to assume it happened already. discussion: Due to the nature of oil science (get money), it is likely that the kind of data one would use to support these claims isn't available. Not until biological sciences really started producing wild food genetics and such would we have had available data. some independent environmentalist data collector from long ago (or even a bunch of them) would not have been able to collect data that anyone would have found useful. Data collection is huge. discussion: There are so many things happening to the surface due to human activities, many of the effects that may have been from changes in hydrocarbon seepage were likely attributed to something else, such as pollution or infrastructure development. Link list: http://www.cartage.o...ydrocarbon.html http://link.springer...297-2_61#page-1 http://ipec.utulsa.e...8.d/28_Abs.html http://microbiology....PetMicrorev.pdf http://www.livescien...r-bp-spill.html http://microbiology....PetMicrorev.pdf http://levin.ucsd.ed...in OMBAR 05.pdf So what the heck is your question? Someguy1221 (talk) 00:51, 6 September 2013 (UTC) does this seem possible/probable/logical??

relation between speed and pressure of the fluid

I could not understand the concept of "relation between speed and pressure of the fluid". I read that where the speed is high, pressure will be low. I could not understand this statement. please elaborate and explain in simple language so that I may have a better understanding to this concept. thanks--39.55.149.184 (talk) 07:13, 6 September 2013 (UTC)

The intro to our Bernoulli's principle article is a pretty nice mix of technical details and lay-language summary if you know a few key ideas. That article defines the principle as "an increase in the speed of the fluid occurs simultaneously with a decrease in pressure". To quote the relevant parts from a few paragraphs later: "Bernoulli's principle can be derived from the principle of conservation of energy. This states that, in a steady flow, the sum of all forms of mechanical energy in a fluid along a streamline is the same at all points on that streamline. This requires that the sum of kinetic energy and potential energy remain constant. Thus an increase in the speed of the fluid occurs proportionately with an increase in both its dynamic pressure and kinetic energy, and a decrease in its static pressure and potential energy." Conservation of energy is a pretty basic idea in science: the total amount of energy must remain constant. The total amount of energy is composed of two parts: Kinetic energy is the energy of motion and potential energy is the energy that is stored (capacity to become/cause motion). Dynamic pressure is the pressure in the direction of motion (like the force of a water jet directed at your hand), and is related to the idea of kinetic energy. Static pressure is the general force pushing outward (causes a garden hose to swell), which is related to potential energy (because the liquid is just pushing not actually moving). So if the flow increases, the kinetic energy increases (more motion), which means the potential energy decreases (to keep same total energy) and therefore less static pressure. DMacks (talk) 08:11, 6 September 2013 (UTC)

Another way to see that is that if the air is moving from the high pressure to the low pressure, the net pressure force will point along the direction of the motion and the air will accelerate aquiring larger speed at the low pressure location. Dauto (talk) 11:54, 6 September 2013 (UTC)

Laminated beams

Can someone explain to me please, whether a beam made of 4 strips of 1/4 inch by 1 inch mild steel bolted and clamped together (flat sides together, thus forming a 1 inch square laminated beam), would be any stronger (more resistant to bending) than a solid 1 inch square bar of the same material? If it is stronger, where does it get this extra strength from? I can't find any information on this by googling. Thanks in advance 122.108.189.192 (talk) 08:27, 6 September 2013 (UTC)

Our Engineered wood article has quite a bit of information and relevant links. I gather that part of the gain in stiffness is due to cross-orienting the stiff axis of alternate layers; bonding of layers also prevents sliding as one mechanism for flexing. -- Scray (talk) 12:24, 6 September 2013 (UTC)

It's been a long time since I took engineering, but I will take a stab at it. The failure actually occurs because compressive forces make the top of the beam want to spread sideways. The bolts and clamps add to the strength by preventing this sideways deformation. Presumably, if you put the exact same bolts and clamps on the solid piece, it would be just as strong. Take this with a grain of salt, because I am using very old neurons. Tdjewell (talk) 12:25, 6 September 2013 (UTC)

Yes - but wood isn't a homogeneous material - our OP wants to know about mild steel. Certainly plywood is much stronger than a solid piece of wood of the same thickness...but that's because of the way the grain of the wood flexes and breaks. Also, I don't think we're being asked about failure modes - only about resistance to bending. I'm not sure what the answer is - but I don't think using wood as an analogy delivers the correct answer. SteveBaker (talk) 12:46, 6 September 2013 (UTC)

It is certainly dubious looking at what happens with wood. For mild steel, first, we need to make a couple of assumptions: We'll assume the volume of steel in the bolts is very small compared to the volume in the mild steel strips. On the limitted information the OP has supplied, this may not necessaily be a good assumption. We'll also assume the bolts are perfect clamps that allow no slip but do not compress the strips anywhere near their their elastic limit. We'll also note that the OP has defined "strength" as resistance to bending. There are of course other forms of strength, eg resistance to breakage or permanent deformation. With all these assumptions, there are two cases.

First case, the bending load is small: Since the elastic strength of steel is the same in both compression and tension (unlike say concrete), a light bending load causes equal stretching on the top of the curve as compression on the inside of the curve. In this case we can see that it makes no difference whether we have clamped strips or just one thick bar - the strength is the same.

Second case, the bending load is high: In this case, the strip(s) on the inside of the curve can buckle inwards, away from the outer strips. Buckling converts the stress in the buckled strips from pure compression into a mix of local compresion and tension. This allows the whole multistrip assembly to bend more. For large loads, the strength of the strip sassemble is thus lower than the single thick bar. Note that the amount of bucking may be imperceptable to the eye but still significantly lower the resistance to bending. In theory, if each strip is made very very thin, in the limit a multistrip assembly will have no resistance to bending at all. However, if the spacing betwene bolts is reduced, the strength is progressively brought back to that of a solid bar. Visualise bending a 100-page A4 book (say 9 mm thick) with your hands. Easy isn't it? Now visualise bending a piece of cardboard the thickness of 100 pages - can you do it? Only if you are a gorilla.

As you increase bending load on a multistrip steel strip assembly from zero, the bending increases linearly up to the point of buckling, the same as for a single thick bar, then it suddenly "lets go" to a certain extent.

Now we can look at bending loads beyond the elastic limit. As the strips on the inside of the bending curve can buckle, the point at which the assembly goes beyond its elastic limit fails is delayed. While a multistrip assembly is easier to bend, it can take higher loads before actually failing. As the strips are increased in number and made thinner, the assembly becomes more and more indestructable.

In a practical assembly, some slippage may occur between strips at each bolt. This obviously lowers the assembly elastic limit, but increases the load at which it will fail.

In a practical case, the bolts will elastically compress the strips - "pre-loading" them. The elastic limit to bending stress is thus reduced, and the assembly will fail at a lower bending load. However this effect should be quite small with properly selected and installed bolting or clamping, and can be neglected.

The non-linear response to bending loads combined with a higher resistance to failure is one reason why leaf springs were used for car suspension until the development of variable rate coil strings and hydraulic shock absorbers (which are actually vibration dampers), and are still used on heavy trucks. In such cases clamps where used instead of bolts to allow slippage and thus make the response even more non linear, and to introduce frictional damping, so that large shock absorbers are not needed.

120.145.46.27 (talk) 15:38, 6 September 2013 (UTC)

It would be weaker in bending, and substantially so. The bolted laminate beam would experience substantial shear forces at the boundaries between the layers, which would be concentrated around the bolts. The solid beam would have similar overall forces, but they would be distributed (relatively) uniformly throughout the beam. --Carnildo (talk) 23:51, 6 September 2013 (UTC)

(OP)Thank you all for your comments, I hadn't thought about the idea that the laminated beam would allow more deformation before actually "letting go". the laminated beam that prompted my question is actually stainless steel and used on a powerboat supporting the base of the rudder, so is subject to a lot of vibration. Maybe it was tried as an experiment to allow slightly more flexing without causing "work hardening" (something stainless steel is notorious for). 122.108.189.192 (talk) 07:44, 7 September 2013 (UTC)

Is there a list of human organs weight?

I'm looking for a list of human organs weight from the heavy to light, or vise verse. In example what is the heavy organ in the body? (skin & liver) and what is the light organ of the body? (I don't the answer). In sum up, I would like to get proportion about the body organs (weight & size). 95.35.210.39 (talk) 08:54, 6 September 2013 (UTC)

for a partial list, see [20]. Most such lists of normal weights cover only the organs weighed at autopsy, and so exclude the skin. -Nunh-huh 09:39, 6 September 2013 (UTC)

Why did not remain nothing nothing?

Why did not remain nothing nothing — Preceding unsigned comment added by 37.238.108.105 (talk) 11:55, 6 September 2013 (UTC)

Because something happened. --Jayron32 12:06, 6 September 2013 (UTC)

(ec) I'm assuming you're talking about the beginning of the universe, or "before" the big bang. Why would you expect nothing to remain nothing? What rules would have prevented it from becoming something? You also probably shouldn't assume that there was ever nothing. I don't have a name (talk) 12:11, 6 September 2013 (UTC)

Sometimes, there are questions that science can't yet answer - and this is definitely one of them.

The short answer is "we don't know" - or possibly "we don't know yet" - or possibly even "we can never know". Personally, I believe the last option is the most likely. To the best of our present day knowledge, the universe started with a "singularity" - a dot of zero size and possibly infinite mass - in which time was literally stopped and space itself was distorted to a point of zero size. No information can come from "before" that because without time flowing, there cannot be a "before". So in that view, there never was a time when there was nothing. The whole concept of "before" is meaningless when relativity says that infinite mass in zero space stops time. I recognize that this is not the only view of how the big bang started - but it's an answer that works and doesn't violate principles that we broadly understand.

There are many other possibilities, that the universe ends with a "big crunch" when all of time, space, matter and energy is sucked into a gigantic black hole - which then explodes in a big bang to recreate the universe. With that scenario, there could have been an infinite number of bang/crunch cycles, each starting and ending with a singularity that prevents any knowledge of the previous universe from leaking into ours. It's even possible that time loops around so that the universe repeats itself over and over forever, exact in every detail.

But all of those kinds of hypothesis require that the universe started in a singularity - then no information from "before" can possibly pass through the singularity into the present universe - so it seems likely that we can never know what there was before. Without that knowledge, your question doesn't have an answer.

You might find the "Weak Anthropic principle" (WAP) useful in thinking about this. It basically says that in any universe where the conditions would not be enough for intelligent life to eventually form, nobody would have been around to comment on it. It follows that the universe had to have the right characteristics for us to be here.

There are any number of other ideas - things like the Simulation hypothesis that says that the universe is just a software program running in a gigantic computer in "the real world"...I work in computer games and simulation - and when I look at the universe as we know it, there are many aspects of the laws of physics that seem like they were perfectly tailored to being a part of a simulation.

But the bottom line is that (for sure) we don't yet know...and (perhaps) we'll never be able to know, not even in theory.

SteveBaker (talk) 12:40, 6 September 2013 (UTC)

This problem may be an artifact of making the assumption that something exists at all. Similar to assuming that God exists who created the universe and then asking who created God. An obvious possibility to explore here is that God may not exist in the first place, but this is not so obvious to people who are indoctrinated with religion. Similarly, we all assume without any shred of evidence that there exist such a thing as "physical existence" which is supposed to be fundamentally different from merely "mathematical existence". An obvious possibility is to start exploring if in fact "physical existence" = "mathematical existence" as e.g. Max Tegmark has proposed. This hypothesis has yet to be falsified. Count Iblis (talk) 14:23, 6 September 2013 (UTC)

Does it matter? Suppose we dig down deep into string theory (or whatever) and find that at the root of all things, it truly is all just math - does that change anything at all? We'd still want to know more about these "physics" that emerge from the abstract mathematical substrate underlying all things. There are plenty of other ideas of that nature out there: That all of time already exists and we only feel the way we do because the nature of our organic memories is that they only contain representations of things to the left of wherever they are in time and not to the right...or that only this precise instant exists or has ever existed and that all of this memory is just a frozen artifact of the way things are. Or that we merely represent a point in Configuration space (Neil Stephenson's fiction "Anathem" is a great way to 'grok' this concept), or that the universe that we know is just a computer game being played by some uber-geek kid on an uber-computer in his bedroom out there in the uber-universe...and that his universe is also just a simulation...and that we are just now beginning to make our own tiny universes inside our own computers.

Sure, there are a million unfalsifiable prospects out there (including a god or gods, the simulation hypothesis and string theory) - but how do you choose between unfalsifiable hypotheses? The only approach we have is to resort to things like Occam's razor and Russel's teapot that fail us when common-sense and appeals to "simplicity" cannot help. SteveBaker (talk) 14:46, 6 September 2013 (UTC)

That applies only when the opposite of the hypothesis is falsifiable. Saying that there is no god or the universe is not a simulation is only falsifiable assuming specific definitions of god and simulation which allow for deliberate and chaotic intrusion into the normal workings of physics; but the most dignified presentation of either idea allows no chance of such falsification. With an interesting middle ground where people suppose that maybe just and so it can be falsified, which is just the point at which you have to either put up or shut up based on evidence obtained in such a manner. Wnt (talk) 19:51, 6 September 2013 (UTC)

"Why did not remain nothing nothing?" Because there was nothing to prevent it from turning into something. Dauto (talk) 21:02, 6 September 2013 (UTC)

You should provide references, Dauto: because there was nothing to prevent it. μηδείς (talk) 00:43, 7 September 2013 (UTC)

can anyone help with references?

The ref desks are for asking questions, not for proposing theories. SteveBaker (talk) 12:19, 6 September 2013 (UTC)

Has anyone seen things that might support the idea that because microbes live in hydrocarbon reserves and seepage, the reserves might be ecologically important??? I can't find direct references to the idea, although I can find information bits that seem to be relevant to the topic. I post/pasted my argument yesterday, but didn't ask for references, which is my search goal. The concept is currently apparently undecided. I'll post my argument again, and at the end are some links. these links show how microbes are responsible for all the functions that would mean they are important, and they are capable because seepage and reserves allow them to be in that place. it's a little long, but not bad.... argument:: we are wrong about certain important aspects of ecology, both historically and presently. we are not crediting fossil fuels with their worth while underground. currently we state that it is un-important to the bio-sphere if we harvest fossil fuels, although pollution is damaging. I argue that indeed it is important to life both on the surface and underground that fossil fuels remain in place. claim: the recent discovery of microbial populations in deep hydrocarbon reserves should support the claim that there were microbial populations in shallow reserves. claim: The density and quality of hydrocarbons within a reserve affects the type and volume of microbial activity (although it is something I've considered that after getting what we can from a reserve, there might be a short term bloom given the newly found relaxed environment. hydrocarbons of high complexity can be broken again and again for energy) claim: Harvesting fossil fuels dramatically alters the subterranean environment, and therefore the biologic activity. claim: This affect in turn affects the surface. Hydrocarbon seepage is reduced with reduced reserve pressure. discussion: WE farmed and deforested nearly everything. We did a lot of replanting. the vegetation as it is today in nearly every location has changed 100% . Lots of things died on their own or were replaced by invasive species. actually, we can't ever know about invasive species of the time. If it's going on now, I would think it's ok to assume it happened already. discussion: Due to the nature of oil science (get money), it is likely that the kind of data one would use to support these claims isn't available. Not until biological sciences really started producing wild food genetics and such would we have had available data. some independent environmentalist data collector from long ago (or even a bunch of them) would not have been able to collect data that anyone would have found useful. Data collection is huge. discussion: There are so many things happening to the surface due to human activities, many of the effects that may have been from changes in hydrocarbon seepage were likely attributed to something else, such as pollution or infrastructure development. Link list: Link list: http://www.cartage.org.lb/en/themes/sciences/earthscience/geology/oilandgas/HydrocarbonMigration/Hydrocarbon/Hydrocarbon.html http://link.springer.com/chapter/10.1007%2F978-3-642-05297-2_61#page-1 http://ipec.utulsa.edu/28.d/28_Abs.html http://microbiology.okstate.edu/faculty/mostafa/publications/PetMicrorev.pdf http://www.livescience.com/23126-bacteria-sucked-up-200-000-tons-of-oil-after-bp-spill.html http://microbiology.okstate.edu/faculty/mostafa/publications/PetMicrorev.pdf http://levin.ucsd.edu/publications/Levin%20OMBAR%2005.pdf — Preceding unsigned comment added by 67.155.62.160 (talk) 12:01, 6 September 2013 (UTC) Uhh. the encyclopedia is for finding information. you read the topic, and give information as a reference person. in order to ask the question, I have to tell you what I'm finding info about. Please take this to the Talk page. SteveBaker (talk) 12:41, 6 September 2013 (UTC) the talk page looks different. I don't want to talk to an individual I want to walk away with references to relevant information to support of refute my argument. HOwever, whatever. I can post again. I can paste for days. what I'm looking for doesn't really get clearer because I say "does it" before everything. to all: click the show button on the green field to gander at answering. — Preceding unsigned comment added by 69.24.176.113 (talk) 13:08, 6 September 2013 (UTC)

Somehow your links literally have three dots in them and can't be followed. You have an interesting idea which is indeed interpretable as a question (what is the ecological role of biota in oil reservoirs?) Apparently it helps greatly to have both oil and water for microbe growth [21] and the natural microbes can assist in oil extraction [22]. According to this book microbes over many millions of years convert debris to petroleum, mobilize the petroleum, and also assist in its recovery. Since many oilfields have turned naturally into oil seeps, liberating carbon and methane to the carbon cycle, I imagine the effect of these microbes on the environment has been substantial. --WHOOOPS!! I fixed the links. Hilarious! .. I want to make a comment on the liberated carbon. a hydrocarbon is an energy source for organisms, they need not get energy from other sources. metabolism is combustion. cool!! (I've heard the theory that deep life might contribute to earths heat, meaning life can increase the cooling time for earth by storing solar power in photosynthesis and then combusting it in subterranean biomes. off topic.) So these organisms in seepage can add to the surface life without taking away. Wnt (talk) 17:25, 6 September 2013 (UTC)

Feeding live mice to a cat

Edit: I should probably say that some of you might find this video upsetting.

Something I just saw in a YouTube vid here. I know what carnivory and predation entails and that animals eat other animals all the time, but is it really healthier for the cat to feed it the mice whole - and still alive? I'm just wondering if this is really considered nescessary or not - or is it yet another person doing something stupid with animals on YouTube? --46.208.75.245 (talk) 14:37, 6 September 2013 (UTC)

This is a serval, a wild cat, and I assume it has similar things in the wild. Domesticated dogs have specifically evolved to eat more starches [23] - I would suppose the same is true of other domesticated animals, including cats and humans. But mammalian carnivores double as scavengers - I know snake owners feed live mice for a reason, but even lions will eat dead meat. Interesting to compare Luka Magnotta, who put the shoe on the other foot and was vilified and hounded until he snapped; many believe animals are equal to humans but not apparently not so many find them equal to one another. Wnt (talk) 17:15, 6 September 2013 (UTC)

Sorry, I thought that "serval" was a (large) breed of domestic cat. I think that it's generally advised that you don't feed your snake live food, because a mouse/rat/rabbit/etc. can do a lot of damage with teeth to a snake while it's being subdued. They will definitely eat pre-killed stuff. As far as I know, it's snappers that will only eat live prey. --46.208.75.245 (talk) 18:44, 6 September 2013 (UTC)

I stand corrected! The moment I typed the "know" I should have realized I was swallowing something I'd heard once, rather than thinking about it. Wnt (talk) 19:34, 6 September 2013 (UTC)

ATOMIC MASS AND MOLECULAR MASS

i need 5 differences between molecular mass and atomic mass ... can anyone help me ... i want a proper difference ... plz rep me soon .. hope u will be able to give my answer ... (139.190.134.121 (talk) 15:17, 6 September 2013 (UTC))

See molecular mass and atomic mass - we aren't going to do your homework for you. AndyTheGrump (talk) 15:29, 6 September 2013 (UTC)

clonning

what is clonning ??? (139.190.134.121 (talk) 15:21, 6 September 2013 (UTC))

I've no idea what 'clonning' is. We do however have an article on cloning. AndyTheGrump (talk) 15:26, 6 September 2013 (UTC)

Having a clone is like having a twin. If a copy of the genetic code of a life form is used to create a new life form, that new life form is a clone of the first. Dauto (talk) 18:55, 6 September 2013 (UTC)

Why aren't galaxies really bright?

If you take a star and move it farther away from the Earth, our eyes will detect a smaller rate of photons from the star. But its angular area will decrease by the same factor, so the star's angular intensity will remain constant. It seems to follow from this that the stars of distant galaxies should be as bright as the stars closer to home. So why can't the naked eye see them? 65.92.4.247 (talk) 19:22, 6 September 2013 (UTC)

You have a finite number of rods and cones in your retina, and to get one to fire takes a certain number of photons (I think under some conditions a rod can fire because of a single photon, but in any case it takes at least one). So a constant brightness in terms of flux per steradian doesn't help much if you have, I don't know, a quadrillionth of a steradian or something. You just don't get enough photons for your visual system to say "ahah, there's a star". --Trovatore (talk) 19:29, 6 September 2013 (UTC)

Also the total integrated apparent brightness of the nearby galaxies isn't that big anyway. E.g. the Andromeda galaxy has an apparent magnitude +3.44, but it is quite a bit harder to spot than a star of apparent magnitude +3.44 because of what Trovatore says above. See also this account of how hard it is to spot M81with the naked eye which has apparent magnitude of +6.94 compared to stars that have larger apparent magnitudes. Count Iblis (talk) 19:53, 6 September 2013 (UTC)

Agree with Trovotore. In theory, the Andromeda galaxy is far brighter in spots because it has bright blue stars in it. But in practice, seeing full brightness requires an entire receptor to be covered, which is just at the lower limit of the distance at which multiple receptors can be covered, i.e. the region in space where a visible disc can be discerned. Apart from a few of the biggest, nearest stars like Betelgeuse these discs aren't actually seen. Wnt (talk) 19:57, 6 September 2013 (UTC)

Also, the human eye has limited resolution because of spherical aberration which smears the image of distant stars into smudges of very little surface brightness Dauto (talk) 20:42, 6 September 2013 (UTC)

An interesting read relevant to the question is Olbers' paradox. Dauto (talk) 20:48, 6 September 2013 (UTC)

Homemade space suit.

Let's say I discovered a portal in my basement that led to the surface of the moon.

I can't get out and explore unless I have a space suit. I know that space suits are very complex pieces of technology, but how difficult would it be to make one from scratch with hardware store and household materials?

Please hurry. I'm really itching to do my first lunar EVA. ;)

209.182.120.18 (talk) 21:49, 6 September 2013 (UTC)

Hypothetically, if you have such a portal, what's keeping the air in your house once you expose that portal? ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:03, 6 September 2013 (UTC)

Space suit is (naturally) our relevant article. There are two major issues that need to be addressed - air and heat. I'm sure it wouldn't be too tricky to adapt a standard diving suit to work in a vacuum rather than underwater, although I'm not sure that would count as a "hardware store" item. However, cooling the suit would be a bit more difficult. See Liquid Cooling and Ventilation Garment for some details of what you'd have to construct. The main problem would be making the sublimator to transfer the heat from the suit to the lunar vacuum, unless you could run a hose back to your basement and cool the water there. Tevildo (talk) 22:21, 6 September 2013 (UTC)

Another big problem is flexibility. A diving suit would blow up like a balloon and the arm and leg tubes would be too stiff to allow you to bend them. A huge question here is how long you expect to be out of the basement. For a short trip, you could dispense with heating and cooling. SteveBaker (talk) 03:09, 7 September 2013 (UTC)

To begin with, what you're looking for is probably a space activity suit. For purposes of fiction it would be tempting to postulate making one from one of those ridiculous latex suits you see on the internet, plus custom padding, but whatever used would need to be exceptionally strong, I think. Given a good helmet seal I suppose a person could probably survive some trial and error for purposes of fiction, but I don't think I'd want to try it! Wnt (talk) 06:30, 7 September 2013 (UTC)

protein loosing - sperm

How much protein we loose when we take out a sperm (semen)? and what is the important matter (like minerals etc.) we loose when we do that. thank you. 95.35.210.39 (talk) 22:14, 6 September 2013 (UTC)

See Semen#Composition of human semen. To answer your specific question, on average, 171 mg of protein per orgasm. Tevildo (talk) 22:23, 6 September 2013 (UTC)

"To ejaculate" is the proper verb. Sperm is relatively very high in phosphorus, found in the energy providing chemical ATP and its relatives. This is why police can detect its glow with a black light. μηδείς (talk) 00:37, 7 September 2013 (UTC)

Why am I suddenly reminded of General Jack Ripper? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:31, 7 September 2013 (UTC)

September 7

Largest volcano on earth discovered?

Re: Tamu Massif, as mentioned on the main page - how exactly could scientists not have known for decades that something of that size was down there? I mean, finding a 260,000 square kilometre volcano... it's not like finding a set of car keys, is it? Did they just miss it? I'm confused. --46.208.75.245 (talk) 00:26, 7 September 2013 (UTC)

It doesn't have an obvious caldera, and it's over a mile down, and 145 million years old. They determined it is just one volcano by studying the lava flows, which all originate from one center. That's not an easy feat given the physical and time depth and erosion and deformation over that period. μηδείς (talk) 00:31, 7 September 2013 (UTC)

For decades they had assumed that Tamu Massif was formed from several volcanoes that had grown together. Think of the Hawaiian islands for comparison. Each island is a separate eruption center, and hence those islands were formed from a group of related volcanoes. The surprise with Tamu Massif is that the entire feature now appears to have been created by a single volcano. Dragons flight (talk) 01:24, 7 September 2013 (UTC)

Light emitting black hole

As we know black hole emit a Hawking radiation and the smaller the black hole, the more powerful the radiation. Is it possible that there is a sweet spot for a black hole size so its emitted radiation is in the visible light spectrum not just in usual gamma ray? 140.0.229.26 (talk) 01:07, 7 September 2013 (UTC)

As explained in the article, the temperature of black hole Hawking radiation is inversely proportional to mass. To get a sun-like spectrum (e.g. 5000 K), you'd need a mass of about 2×10¹⁹ kg (about twice the mass of Ceres), which implies a event horizon radius of about 30 nanometers. Dragons flight (talk) 01:34, 7 September 2013 (UTC)

Note the evaporation rate according to the article is 3.562 x 10³² W / M² (with M in kg); for the mass given above it should be 8.9 x 10^-7 W. I think that if magnified under a microscope about 4000x it should seem like an incandescent bulb in brightness, but with an arc just (under the scope, appearing to be) 0.12 mm in size the filament would seem a little thin and bright by comparison. Wnt (talk) 06:17, 7 September 2013 (UTC)