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June 30

Plankton

I read on one fact book of mine that plankton makes up 85% of all life on earth. Now that can't be true, right? Or is it? ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 07:17, 30 June 2013 (UTC)

NPR says "Plankton make up 98 percent of the biomass of ocean life", as does this article, so maybe. Clarityfiend (talk) 07:29, 30 June 2013 (UTC)

Check out the article Biomass (ecology). It says most biological carbon is in land life, outweighing sea life by a factor of 50-100, not counting bacteria. There are large unknowns in the distribution of biomass though, bacteria in particular. This all assuming we are talking mass, not number of organisms (I'm guessing bacteria, again, would win a head (sic) count hands (sic) down). 88.112.41.6 (talk) 13:22, 30 June 2013 (UTC)

The table in Biomass_(ecology)#Global_biomass suggests that bacteria win hands-down...but then the commentary afterwards throws doubt in all directions. I think the bottom line is that we don't know. The error bars on all of the stated numbers are huge. The NPR numbers quoted above only tell us what percentage of ocean biomass is plankton - so that doesn't really help.

But the original "fact book" fact is kinda vague. It makes a huge difference whether "making up 85% of all life" means 85% of all individuals, 85% of "wet" biomass, 85% of "dry" biomass, 85% of known species, 85% by volume...it's a very vague term and it's hard to say whether any of those possible meanings are true. It's not impossible that if you pick the right measure - and exclude bacteria or exclude viruses or whatever - that you can make this number come out true - but it seems unlikely.

In all the years I've worked with the Wikipedia reference desk, I've come to believe that anything written in a "fact book" is almost guaranteed to be so vaguely specified as to be meaningless - and most likely, untrue. Those books life and die by having "amazing" facts in them...not boring ones. Hence they cherry-pick the least likely results from the least reliable sources - and write the "facts" in a sufficiently vague manner that it's hard to either prove or discount them. I can't count the number of times people have asked us to fact-check something they read in such books and it's turned out to be nonsense. This one seems to follow that pattern.

SteveBaker (talk) 15:39, 30 June 2013 (UTC)

I always thought fact books were reliable sources... I assumed "all life on earth" to mean out of all living things on earth – fungi, bacteria, animals, plants, etc. ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 08:11, 1 July 2013 (UTC)

Fact books are most certainly not "reliable sources" - we've shown that here many times before. I recall one case where someone posted a couple of dozen "facts" from such a book in a question here - and we gradually found all but a couple of them to be incorrect.

But still, the "fact" doesn't say whether this is 85% by wet mass, by dry mass, by number of individuals, by number of species, etc. So it's just too vague. Also, it's pretty obvious from reading our Biomass_(ecology) article that we really don't have sufficiently good numbers to answer this question definitively. For example, it's only fairly recently that we've discovered extremophile microbes that live inside rocks 1900 feet below the sea floor under 8500 feet of ocean. If those creatures can be found that deep into the earth's crust, then the sheer volume of space that they could possibly occupy would dwarf the thin layer of the surface of the earth that we've explored. The potential for those things to live in such places could easily mean that they are by far the biggest number of individuals, wet and dry mass and number of species...but right now, all that we know is that we don't know. SteveBaker (talk) 14:51, 1 July 2013 (UTC)

Can box turtles crawl in high grasses

On my way home from work I noticed a turtle crawling down the center of the highway (Box Turtle, I think). I have no idea how he didn't get hit, but I decided to pull over and rescue him. I drove a little way down till I found an area that I could put him a safe distance from the road, however, the area had rather thick knee high grass and weeds, which brings me to my question: can turtles pass through this, or is their too much resistance, thus, making them effectively stuck. Honestly, I'd imagine that they would have no problem, but the question crossed my mind while finishing my drive home, I figured I'd ask since it would be a shame to rescue the turtle only to trap it another way! If for some odd reason they can't, I can always go back and retrieve him, Thanks for any help on this seemingly stupid question.Phoenixia1177 (talk) 12:15, 30 June 2013 (UTC)

I don't see how we can help you with sources. But my OR from having kept turtles is that while they wouldn't voluntarily climb in to tall grass (which they don't eat), they should be able to get out. Have you felt the strength of a turtle's legs if you hold one that wants to move or get away? Even if this is a faux pas, don't worry too much. I was getting in the car to leave my waterfront residence on the Great Bay (New Jersey) when an obviously aquatic turtle crawled by my car door. I knew I would pass a lake on the way home, so I put the turtle in a bucket and dropped it off on the side of a nice big freshwater lake about five miles inland. When I got to my apartment in NYC I heard a news story about hundreds of turtles trying to lay eggs on the bayside runways at JFK airport. I looked the animal up and found it was a northern diamondback terrapin, one of the only species of land turtle that prefers salt water. μηδείς (talk) 16:01, 30 June 2013 (UTC)

Ha! It's the thought that counts. More people should try to help urban turtles. Saltwater or freshwater, nobody likes being run over. InedibleHulk (talk) 01:59, 3 July 2013 (UTC)

Agreed. I think the OP is equating slowness with weakness, but this is not the case. The classic example is the weed which pushes up through concrete. StuRat (talk) 13:13, 1 July 2013 (UTC)

Thank you both for the help:-) I figured the turtle wouldn't have an issue, but just wanted to be sure; it defeats the point if not. Also, I realize that this question would be hard to source, but I figured there might be something out there. At any rate, thank you, this put my mind at ease (I'm weird, I know) :-)Phoenixia1177 (talk) 08:58, 2 July 2013 (UTC)

eggs in the afternoon

one of my friends told me that eating eggs in the afternoon isn't good for one's health. but, she couldn't elaborate on that. can anyone please tell me whether there are any health risks if i eat eggs in the afternoon?

thanks — Preceding unsigned comment added by 117.197.233.218 (talk) 14:40, 30 June 2013 (UTC)

We're not supposed to give medical advice, but that doesn't make any sense at all. Looie496 (talk) 15:02, 30 June 2013 (UTC)

A google search on "Eating eggs after noon" brings up dozens of hits from health and diet sites saying things like "Healthy Snacks to Beat an Afternoon Energy Slump: A Hard-Boiled Egg"[1]. The trouble is that absolutely anyone can set up a diet/health web site and say just any old nonsense and people will repeat it as if it were scientific truth. So doubtless your friend read it somewhere - and didn't read the other places that say the exact opposite. This is very typical of these kinds of claim.

Bottom line is that in the absence of any scientific studies where people only ate eggs in the morning and not in the afternoon and vice-versa - with each of them eating "placebo" fake eggs at the other times - then tracked those people's health for months and years afterward, we're unlikely to know for sure. Is it likely that such a study has been done? Hell no! To get any kind of scientific result, they'd have to study a hundred different foods with perhaps a dozen possible time-of-day eating patterns, invent fake "placebo" foods to substitute for each one so people wouldn't know which part of the study they were in ("double-blind") and have hundreds of people in each part of the study and track them for a long time afterwards with detailed health testing. It would be an incredibly difficult and costly exercise - and because there is little expectation of discovering major new health insights, nobody is going to fund such a thing.

So we're left in realms of amateur speculation and so forth. It's really, REALLY, unlikely that what your friend said is true.

May I suggest you ask your friend where they got this piece of information from - let us know the source and we can go an examine how that information was obtained.

SteveBaker (talk) 15:21, 30 June 2013 (UTC)

Maybe if they've been sitting out at room temperature (or worse) since the morning. Otherwise, it's silly. Deviled eggs, for example, are good at any meal. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:20, 30 June 2013 (UTC)

I love the idea of hundreds of research subjects spending years eating either fake eggs or not-fake eggs but not knowing which they are.

Eggs are traditionally a breakfast food, so eating them in the afternoon may be a social mistake but not a medical one. This tabloid source mentions research by the University of Missouri suggesting that eating eggs in the morning has health benefits. It does not suggest that other times of day are bad for eggs. Eggs do contain quite a lot of fat, so eating them when activity levels are higher, rather than lower, may be beneficial.

See also "Go to work on an egg", a 1950s advertising campaign that was banned from being rebroadcast in 2007 because it was felt inappropriate to imply a recommendation to eat an egg every day. --Demiurge1000 (talk) 16:35, 30 June 2013 (UTC)

To elaborate on wanting to eat eggs only when your activity level will be high, it's best to avoid heavy meals, including lots of eggs, right before you go to sleep, since they then tend to be packed onto the body as fat. Now "the afternoon" might be followed by quite a bit of activity for the average person, but for those whose schedule involves going to sleep soon after, then eating eggs in the afternoon could be unhealthy. Of course, eggs aren't particularly healthy at any time. While they do contain protein and lots of other nutrients, they also have a high level of cholesterol. Egg whites lack the cholesterol of the yolks, but also most of the nutrition. StuRat (talk) 13:10, 1 July 2013 (UTC)

Eggs contain lutein and zeaxanthin, which are part of an established nutritional prevention for macular degeneration, so if work involves exposure to bright sun or comparable eyestrain they plausibly could be beneficial - I'm not aware of any published research to say that confidently, however, and the effect of cholesterol on drusen could have the opposite effect in some people. Still, depending on bioavailability parameters for these nutrients, it is at least possible that eggs could be healthier in the morning. Wnt (talk) 17:08, 1 July 2013 (UTC)

Genes and race, what do they code for?

The genes that differentiate the races of two individuals, do they code for the behavioral and temperamental differences between races? E.g. more testosterone in black males and more creativity in whites, analytical thinking in East Asians etc. Can these genetic differences also account for difference in racial IQ and crime rate? — Preceding unsigned comment added by 174.95.168.157 (talk) 18:42, 30 June 2013 (UTC)

No. Virtually all social aspects of "race" are just that - social aspects; genes have little or nothing to do with it. Matt Deres (talk) 20:44, 30 June 2013 (UTC)

Here's a bit of reading: Race and intelligence, Race and crime, Criminal black man stereotype. Matt Deres (talk) 20:46, 30 June 2013 (UTC)

Most of the mass murders in America seem to be committed by youngish white males. The OP/IP should ponder that point for a while before indulging in further hackneyed stereotyping. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:38, 30 June 2013 (UTC)

I don't think we need to assume the OP's question is bigoted any more than we should blame him for geolocating to Canada. But the question does have a false premise--there are no specific genes for specific races themselves. Rather, certain genes tend to cluster statistically in their frequencies among races in whatever sense that word is useful. Genes for higher levels of testosterone might lead to more aggressive behavior, but there are plenty of hyperandrogenic whites and hypoandrogenic blacks. No one would suggest a sensitive black male who likes to crossdress and works in a day care center was actually white or some other race because of that behavior. μηδείς (talk) 21:48, 30 June 2013 (UTC)

"Race" is culturally derived, but certain races as culturally defined often share genes at higher rates, hence may be more likely to share common characteristics like skin color, body features, vulnerability or resistance to certain diseases (e.g., sickle cell, smallpox, Race and health#Single gene disorders). Whether it extends to more psychological attributes is of course controversial. On wikipedia alone it's led to a Bleak House-esque arbitration case. See the links provided. Shadowjams (talk) 01:53, 2 July 2013 (UTC)

Something I was pondering

I was pondering about the nature of reality today and meta-stable states, and thought that given A = "system at local minimum (of energy)" and B = "system in equilibrium", B implies A (or I hope so) and so does A imply B?--Gilderien Chat|List of good deeds 21:13, 30 June 2013 (UTC)

No, there are numerous counterexamples. Unstable equilibrium is a common theme in natural science and in engineering. Our article unstable equilibrium redirects to a general article on equilibrium; and you can also read about stability. There are many instances of a system that is at equilibrium but is not at a minimum energy configuration; and there are many cases where a system is at equilibrium but is not stable with respect to any perturbations from equilibrium. For example, an object orbiting at the L3 point of two other masses is in equilibrium, but is neither stable nor at a local minimum of gravitational potential energy. Nimur (talk) 21:57, 30 June 2013 (UTC)

Would A imply B for all cases then?--Gilderien Chat|List of good deeds 23:16, 30 June 2013 (UTC)

You might have been considering stable equilibria (and I suspect so). Even so, the type of equilibrium remains significant. For example, a system may be in stable thermodynamic equilibrium, but it is plainly not at a local minimum of energy in the sense intended. However, given a purely mechanical system (in which non-zero dynamic properties such as heat are taken as "not in equilibrium"), I suspect that a stable equilibrium (even under perturbations) and local energy minimum might well imply each other. In effect, A would imply B, but then in this interpretation it would also imply a temperature of 0 K. — Quondum 23:28, 30 June 2013 (UTC)

There's more than one definition of equilibrium, but the simplest is that it's a critical point (mathematics) of the potential energy function. Mathematically that can be a local minimum (stable) or a maximum or saddle point (unstable), but in the real world you will never find a system in an unstable equilibrium. So I think A and B are more or less the same. This applies to thermodynamic systems too if properly interpreted (principle of minimum energy). -- BenRG 06:48, 1 July 2013 (UTC)

To think about this more simply - take a real world example. If you put a pingpong ball into a cup - the local gravitational potential energy minimum inside the cup means that you can shake the cup around and the ball rattles around a bit - but stays inside the cup. That's a pretty stable equilibrium. Put the same ball into the bowl of a spoon - and while it's still somewhat stable - a relatively small displacement is enough to knock it out. Put the pingpong ball into a cup during an earthquake and it may bounce out. Both cup and spoon are local energy minima. So stability is not an absolute thing. SteveBaker (talk) 18:50, 1 July 2013 (UTC)

July 1

Malaria

Does malaria exist in Japan since its common in Asia? Clover345 (talk) 07:40, 1 July 2013 (UTC)

statement by banned user retained only because it was answered
The following discussion has been closed. Please do not modify it.
No. Malaria does not occur in Japan. Malaria is spread by mosquitoes and requires a hot tropical climate that supports mosquitoes. Malaria is mainly a problem in tropical jungles that combine high temperatures with plenty of water for mosqitoe larvae to grow in. Japan is too far north of the equator and is thus not a hot tropical jungle region. Malaria cases occured in Japan when soldiers returning from World War 2, having caught it in jungle areas, but as there was no means to efficently spread the disease, once the soldiers recovered, there was no more malaria. See http://idsc.nih.go.jp/iasr/18/213/tpc213.html — Preceding unsigned comment added by 124.178.183.4 (talk) 11:21, 1 July 2013 (UTC) statement by banned user wickwack

Thats so gabbled and inaccurate that it does not start to answer the OP's question. There is no indigenous malaria in Japan anymore because the intermediate host (i.e., humans) infected by malaria are too few now to sustain a reservoir of this disease (due to modern anti -malarial drugs). The climate of southern Japan suits the vector (mosquitos) very nicely (as your ankles will witness in the evenings when they come out to bite). --Aspro (talk) 12:01, 1 July 2013 (UTC)

Indeed. Malaria was also endemic to Britain until the 1950s, when land drainage and modern healthcare eradicated it. Britain's climate is similar to Japan's, and the assertion that Malaria "requires a hot tropical climate" is nonsense. ref. -- Finlay McWalterჷTalk 13:26, 1 July 2013 (UTC)

Regarding malaria in Britain, our article on the history of malaria says "Malaria was once common in most of Europe and North America, where it is now for all purposes non-existent ... in the coastal marshes of England, mortality from "marsh fever" or "tertian ague" ("the ague" from Latin "febris acuta") was comparable to that in sub-Saharan Africa today". Gandalf61 (talk) 15:17, 1 July 2013 (UTC)

Yep, the climate is suitable. According to http://idsc.nih.go.jp/iasr/18/213/tpc213.html there were estimated to be "...20,000 cases of indigenous malaria per annum before the World War II" in Japan. Of course, the anti-malarial drugs and mosquito controls were sufficient to end its malaria problem. If Japan is anything like North Carolina, there have always been enormous numbers of them buzzing biting insects to deal with (we have a particularly large land area and plenty of swamps!). Targeted killing works though. --Modocc (talk) 11:48, 2 July 2013 (UTC)

• There are conflicting accounts regarding Malaria's history in Japan, but the mosquito Anopheles sinensis found in Japan is known to be a vector for Plasmodium vivax (it is apparently refractory to P. falciparum). Malaria is found in many non-tropical areas; for example, it was endemic in much of the United States at one time. -- Scray (talk) 11:38, 1 July 2013 (UTC)

There is a meta-discussion regarding the dynamic IP address at the reference desk talkpage here http://en.wikipedia.org/wiki/Wikipedia_talk:Reference_desk/Science#WickWack_is_back. --Modocc (talk) 04:02, 4 July 2013 (UTC)

How would certain wikipedians do in the World Quizzing Championship?

Really, some of you show an incredible depth of general knowledge when answering questions... I wonder how some of you would do as quizzers in the World Quizzing Championship? I'm posting this here because I was hoping for a scientific answer. Do these quizzers really have an excellent general knowledge like some of you do, or do they have a different type of brain that is trained to retain bits of trivia? On this matter, it seems to me that some of their quizzing questions are a bit contrived and generally limited to western knowledge rather than true global knowledge... I wonder how these so-called eggheads would do given a random sampling of wikipedia's "did you know" questions? Sandman30s (talk) 14:08, 1 July 2013 (UTC)

Not sure. I participated in academic competitions (in the U.S. called Quiz bowl) of various forms throughout HS and College, such as Granite State Challenge, Academic Competition Federation, College Bowl, National Academic Quiz Tournaments, etc. I have a few trophies. --Jayron32 14:33, 1 July 2013 (UTC)

I suspect that most Ref Desk denizens would fare no better than an average person (although there are exceptions). What we do (or at least, what we're supposed to do) is to use Wikipedia and other online information to find references in order to answer questions - and according to the US WQC site: "The World Quizzing Championship takes the form of a written quiz taken by individuals using no reference materials". Kinda the opposite of what we do. Being good at answering RefDesk questions really requires a broad - but very approximate - base of knowledge, combined with being clever at using search engines in creative ways. SteveBaker (talk) 14:34, 1 July 2013 (UTC)

I also think it's quite likely that many of the regulars would object on principle to supporting an organization that thinks a "quizzer" is someone who answers questions, and "quizzing" is the process of answering questions. See quiz. Tevildo (talk) 19:20, 1 July 2013 (UTC)

The average person believes a large number of things that simply aren't true and actually knows very little geography, history, or science. Personally, I would like to imagine that the average Ref Desk responder is at least a little better informed than the average person on the street. At the very least most of the people here at least have some interest in thumbing through the fascinating bits of our encyclopedia, and might just remember some of what they read. Dragons flight (talk) 20:49, 1 July 2013 (UTC)

For SteveBaker, I would add from my experience that answering questions on the ref desk seems to be about adopting the most pedantic interpretation of a question that you can, and giving a silly answer to it. I've seen this quite a lot. As far as this question goes, I think most brainiacs would find it very easy to answer the "did you know?" questions: they would just say "yes" to all of them. And if that's not pedantic, I don't know what would be. As for the question, Australian quiz champ Vincent Smith just said to read widely. It means you would usually have a very good general knowledge. It would not necessarily be deep, but you would be more than just a fact machine. IBE (talk) 09:20, 2 July 2013 (UTC)

I agree that there is an unfortunate tendency to do that. It's much easier to produce a stupidly pedantic/silly answer than to figure out the true answer and reply properly. We try to discourage this kind of bad behavior and to "weed out" the individuals involved - however, this is "The Encyclopedia That Anyone Can Edit" - and unless these people are actively breaking our rules, it's hard to ban the useless ones. Also, there is a problem that there can sometimes be a thin line between a stupid answer and a decent one. Often our OP's need to be a little patient in order to get the answer they need! SteveBaker (talk) 14:39, 2 July 2013 (UTC)

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Comment: I think some silly answers are posted by people who take after Marvin the Paranoid Android who has a brain the size of a planet but is never given the chance to use it. They may well 'feel' (as opposed to think) that some eloquent posters of questions could get far quicker -all most instantaneous- answers by taking this advice (?):[[2]]. In my experience for example, a good librarian is one that not only finds your answer but shows you how you can navigate your own way to answering your next question. Of course, if a poster to a question doesn’t know how to navigate, using what s\he already knows (and to cross reference as a check, that the info is sound) – then their options are limited and thus we are here to help. Well, some of us. ---Aspro (talk) 19:57, 2 July 2013 (UTC)

Two questions about the blood donation or blood test

Hi, I would like to ask two questions about the blood donation or blood test: The first question is: How long after donating blood or blood test that takes the blood to produce the same amount of the blood out of out from the body as I understand it is a process which takes time to create blood cells in the bone marrow and does not ends up by drinking liquids ...

And the second question is: Is there is any advantage physiologically in a blood test? (Note, I'm not talking about the importance of the tests themselves but if there is any _ benefits in taking blood out from the body in the case of an ordinary person who is not suffering from polycythemia - Multiple in taking blood). Thank you. מוטיבציה (talk) 15:35, 1 July 2013 (UTC)

I don't have an answer for the first question, but for the second question, our article on bloodletting says that it is not considered beneficial except for a few specific conditions, most notably iron overload. Looie496 (talk) 17:46, 1 July 2013 (UTC)

According to the UK blood service "it takes several weeks for all the red cells to be replaced [after a donation]". Platelets and white cells are replaced "over the next few days". The minimum gap between donations in the UK is currently 12 weeks for men and 16 weeks for women, but for donations by apheresis (where the red cells are returned to the body during the donation) the gap is less (a month when I used to do it, though that was quite a while ago). AndrewWTaylor (talk) 17:59, 1 July 2013 (UTC)

Note that the amount of blood taken in a blood test is "only a small amount" [3] whereas a blood donation (in the UK at least) is 470 ml [4] or 0.83 of an Imperial pint, plus various samples that are tested for HIV, hepatitis and so on. Alansplodge (talk) 20:36, 1 July 2013 (UTC)

what is the purpose of the breathing from mouth to mouth in CPR?

What is the purpose of the breathing in the life support CPR? I heard that the goal of the mouth among 30 massage of the heart is actually to stimulate the respiratory system or the control area in the brain responsible for breathing, by carbon dioxide (CO2). Until then, I thought that the goal is just to put oxygen into the mouth of the unconscious person. I'd love to sort the issue. Thanks מוטיבציה (talk) 17:40, 1 July 2013 (UTC)

The purpose is to move oxygen into the lungs of the unconscious person, if they are not breathing. --Demiurge1000 (talk) 18:03, 1 July 2013 (UTC)

I agree with Demiurge1000. The idea of stimulating respiration with CO2 is contradicted by the protocols for more advanced rescuers, who always switch to pure O2 as soon as the equipment can be set up. Jc3s5h (talk) 18:07, 1 July 2013 (UTC)

Cardiopulmonary resuscitation says: "Current recommendations place emphasis on high-quality chest compressions over artificial respiration; a simplified CPR method involving chest compressions only is recommended for untrained rescuers", confirming what I've been told by people who've been on First Aid courses recently. AndrewWTaylor (talk) 18:14, 1 July 2013 (UTC)

Does it mean that whwn we put oxigen into the mouth of the unconscious person, and then we compress his chest, the oxigen come in into the blood? מוטיבציה (talk) 18:46, 1 July 2013 (UTC)

Blood oxygenation doesn't work that way. Oxygen diffuses from the lungs (not mouth) passively (not caused by other actions) into the blood. Circulation just circulates the oxygenated blood to other parts of the body. You might want to read our articles about and breathing and the circulatory system to make sure you understand these basic features. DMacks (talk) 18:54, 1 July 2013 (UTC)

Of course, maybe I didn't explain myself properly, but it's clear for me the way of the air/oxigen come in into the blood through the lungs, my question was about the CPR specificly.I would like to know if the air we put into the mouth of unconcious person, it's come in into the blood by our combination of the chest compression and breathing. Note, I don't mean about the reserve oxigen in the blood that we move in the body by our compressions, I mean about the NEW air we breath from mouth to mouth or even by oxygen bottle. it means that I would like to know if the mechanical act that we do, makes the same act when the heart work by itself. thank you for the links. מוטיבציה (talk) 20:07, 1 July 2013 (UTC)

Oxygen gets into the bloodstream through the cell membranes of the alveoli. Mechanically breathing for someone (mouth to mouth resuscitation) is meant to ensure that fresh air gets into the lungs so that oxygenation of the blood can occur. The chest compressions are to do with ensuring blood circulation, not an attempt to squash the lungs to reproduce breathing. If you think about it, you will see that the speed of chest compression is nearer to the speed of the heartbeat than to the pace of breathing. --TammyMoet (talk) 20:38, 1 July 2013 (UTC)

So, I can understand that you say that the oxygen (of the breating) get into the bloodstream by the time of the CPR. Do I understand well? מוטיבציה (talk) 21:54, 1 July 2013 (UTC)

You may or may not understand well, but I do not understand you well. If the blood (around the lungs or otherwise) is already well oxygenated "by the time of the CPR" (which appears to mean "before the CPR begins"), then only chest compressions are necessary, and artificial respiration (mouth to mouth) is not.

This is incorrect. Oxygen is still required by the body during chest compressions.217.158.236.14 (talk) 11:13, 2 July 2013 (UTC)

Or what is it that you mean? The purpose of the artificial respiration (mouth to mouth) is to increase the oxygen concentration in the lungs, with the result that more oxygen is absorbed into the blood around the lungs. The purpose of the chest compressions is to move that blood (and other blood) around the body, including in particular to the brain. --Demiurge1000 (talk) 23:43, 1 July 2013 (UTC)

Modern first-aid training for the common person uses only chest compressions. The compression of the lungs forces air in and out as well as compresses the heart muscle. 217.158.236.14 (talk) 11:13, 2 July 2013 (UTC)

If you get proper training (and not just through the Internet, you'll learn to perform mouth-to-mouth. Chest compressions only is only recommeneded for the inept. OsmanRF34 (talk) 18:03, 2 July 2013 (UTC)

Incorrect, dangerous, and insulting statement - if you get "proper" training, you'll learn to use a ventilation device such as a pocket mask/BVM. No-where recommends mouth to mouth anymore. You'll also learn that for anyone who doesn't do it regularly enough to retain the skill, compression only CPR is recommended, and according to the evidence just as useful (if not more useful) in the hands of a lay responder. So it's not "for the inept", but for the evidence based and competent. Nickopotamus (talk) 3:47 pm, Today (UTC−4)

E 85 (Ethanol vehicles)

Can an E-85 vehicle be run just on gasoline? 190.140.206.17 (talk) 20:01, 1 July 2013 (UTC)

Yes. A few points of clarification: E-85 is the fuel, not the vehicle. The vehicle is called a flexible-fuel vehicle, and our article says they run on pure gasoline. Note that whether "normal" cars should use E-85 is contentious, and described at E-85#Corrosion_debate . I am not aware of any production vehicle that is designed to only run on E-85 or ethanol. SemanticMantis (talk) 20:30, 1 July 2013 (UTC)

E85 means 85% ethanol and 15% gasoline. Once running, most standard internal combustion engines will run just fine on E85...for a while! The problem is that the ethanol is quite corrosive and can dissolve some plastics and rubbers found in seals and hoses. As the percentage of ethanol increases, some cars become harder to start - but most run OK once you do get them started. Flex-fuel vehicles are basically made with the appropriate plastics and metals to resist this corrosion and have engine management computers that handle the startup thing properly.

My 1963 Mini Cooper has rubber parts that even E10 fuel (which is standard in most of the USA) will eventually corrode/dissolve - but modern cars have synthetic materials that protect them at least to that degree.

In Brazil, most people run their cars on 100% ethanol - using a small amount of gasoline in a separate tank just to get the car started. In theory, they shouldn't convert standard vehicles to do that - but they do, and they get away with it - noting that they have to replace some parts more often than they otherwise would - but if you're driving an old junker, the thing will probably die for other reasons long before ethanol corrosion becomes an issue.

SteveBaker (talk) 14:33, 2 July 2013 (UTC)

You are not quite right about Brazil. Indeed they use flexible-fuel vehicles that run on a combination of gasoline (E20-E25 blend) and hydrous ethanol (E100). OsmanRF34 (talk) 17:52, 2 July 2013 (UTC)

Also, I believe the air/fuel ratio for ideal combustion is different with gasoline and E85. It may still run at the other ratio, but it won't be very efficient. StuRat (talk) 03:25, 3 July 2013 (UTC)

Flex fuel vehicles automatically adjust to keep the mixtures correct according to our article. Rmhermen (talk) 03:59, 3 July 2013 (UTC)

Many older cars is Brazil are not flex-fuel and were specifically designed to run on ethanol. These cars will not run well on gasoline. The main problem is not the difference in air to fuel ratio which can easily be adjusted. The problem is the different compression ratio of ethanol based engines which will lead to engine knocking if gasoline is used. Dauto (talk) 17:54, 4 July 2013 (UTC)

July 2

Mars will definitely survive or it is possible to get eaten by sun

I am trying to find an outside source say Mars may get swallowed up by sun in 6-7 billion years [5] I can't remember every source I visited in the history stating Mars may even get eaten up by sun. Is the best answer to state Mars will definitely not get eaten by sun in 6-7 billion years or best answer is since Mars is further away from sun than Earth is it stands at better chance surviving than Earth? I don't know who said sun's expansion can reach 2 AU. Maybe our diagram is somebody made mistake, because I can't find other source said 2 AU?I am guessing somebody on Wikipedia made mistake--69.233.254.115 (talk) 02:04, 2 July 2013 (UTC)

This is what Wikipedia has to say on the subject. There is always a bit of fuzziness as to predictions and models of future events, in terms of what will happen to the sun and how large it will get at its maximum extent. There are some educated guesses as to how big it is likely to get, but we can't predict it down to the inch. There are going to be some significant differences from one model to the next. --Jayron32 02:23, 2 July 2013 (UTC)

That diagram shows the sun at Earth's orbit - 1 AU radius or 2 AU diameter. Not out past Mars. Rmhermen (talk) 18:35, 2 July 2013 (UTC)

"Through the Wormhole" Season 4 Episode 3 agrees that the sun going supernova will not swallow Mars. Sandman30s (talk) 20:08, 2 July 2013 (UTC)

Not while Mars is where it is, anyway. Entirely possible it may be knocked closer by some huge asteroid within the next several billion years. Or something else happens that scientists don't yet think can happen. Long time to go. InedibleHulk (talk) 02:13, July 3, 2013 (UTC)

What's pictured in this astronomical photo?

A photo of the Andromeda Galaxy.

Is there somewhere that will tell me what the other objects in this file are? I just have a curiosity about what the big blue object is to the lower left of Andromeda is or what the wide yellow object is in the lower center of the image. Once I was curious about those, I looked more and kept asking "I wonder what that is too!" about various other points of light. So, maybe if there was a site where I could click and zoom around from the Earth's point of view, that would answer all my questions. Is there such a site? Thanks, Dismas|^(talk) 05:00, 2 July 2013 (UTC)

Stellarium has a very complete catalog of stellar and deep sky objects, and its interface is suitable for beginners as well as expert users. It is free software but it is not web based. I also like the user interface in KStars. If you want a very complete catalog of astronomical objects, suitable for professional use, I'm sure we can point you to some more thorough catalogs, but these tend to require a lot more effort to use. Nimur (talk) 05:19, 2 July 2013 (UTC)

(For example, once you know the object's coordinate, you can use, e.g. Hubble's digital sky survey catalog, and and just type in coordinates. Most users probably want something a little easier). Also keep in mind that just because something appears point-like and distinct in one image product, that does not mean that it's a distinct astronomical object. So what you see in false color - your photo is mostly composited from invisible ultraviolet light! - gets rendered as a "bright blue point-like star" - but the same area shows as a continuous and nondescript piece of blurry gas in visible light in Hubble's catalog survey. Many very dramatic astronomical photographs are generated using equal parts image-processing science and artistic license to manipulate the input image data. Astrophysicists pore over the spectral data trying to deduce what structure might actually exist in these distant objects. Nimur (talk) 05:31, 2 July 2013 (UTC)

I've found the site Atlas of the Universe to be a fascinating place to visit over the years. --TammyMoet (talk) 11:22, 2 July 2013 (UTC)

Google Earth now has a Google Sky star field in it; I've found it very easy to use, already being familiar with the GE navigation. You can apparently view "Sky" through a browser, but I haven't tried that. Matt Deres (talk) 11:28, 2 July 2013 (UTC)

Google Sky made it impossible for me to ever view our planet as important again. But yeah, that doesn't cancel out the coolness of it. Adds to it, really. InedibleHulk (talk) 02:23, July 3, 2013 (UTC)

Thanks for the links, everyone. I tried Google Sky but it doesn't name every, or even most, object(s). Dismas|^(talk) 23:56, 2 July 2013 (UTC)

There's a list of hierarchial checkboxes of things to label in the left-hand pane. Many are unchecked by default. You may want to fiddle with that, if you haven't. InedibleHulk (talk) 02:26, July 3, 2013 (UTC)

admission for engineering

hey people I have got into institute if chemical technology for btech oils for first year engineering. wats d opportunity for campus placements? nd does it make a gud branch? — Preceding unsigned comment added by 59.183.34.74 (talk • contribs) Looie496 (talk) 06:41, 2 July 2013 (UTC)

Presumably that's the Indian Institute of Chemical Technology. On Wikipedia our convention is to spell out words, not write them in text-speak. Looie496 (talk) 06:46, 2 July 2013 (UTC)

I've got this song stuck in my head...

...and I'd be too embarrassed to tell you what it is. Fortunately, I know from experience it'll be a different song tomorrow. But seriously, it seems it happens to a lot of us. Has any serious research been done on it? How much of the population does it happen to? Does it vary between cultural groups? I sometimes wake up with a song going round in my head that I haven't heard or thought about in years. Is that common? What's really going on with this? HiLo48 (talk) 07:42, 2 July 2013 (UTC)

Our article on earworms says that "according to research by James Kellaris, 98% of individuals experience earworms". There are a while bunch of references in that article that might tell you more. Gandalf61 (talk) 07:49, 2 July 2013 (UTC)

Thanks. I'll have a look at that. But the name. Earworms? Never heard of it. No wonder I couldn't find that article. (I did look for one.) The article doesn't have an etymology section. Where did that name come from? (Yeah, I know, it's probably in the sources, but is that name really common?) HiLo48 (talk) 09:06, 2 July 2013 (UTC)

There's an interesting discussion at Talk:Earworm#Requested move. It's apparently a translation of the German Ohrwurm, but I've seen the English word mentioned frequently in books and articles on popular culture. Ghmyrtle (talk) 09:18, 2 July 2013 (UTC)

Sounds like a metaphorical equivalent to Earwig. The TV show Brain Games talked about this phenomenon, and if you google the subject [tune stuck in head], there are endless references. It is thought to have some connection to survival instincts. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:30, 2 July 2013 (UTC)

Oh so there is such a term! Hehe, remember watching a good ol' SpongeBob SquarePants episode titled Earworm... It really was a worm. :P ☯ Bonkers The Clown \(^_^)/ Nonsensical Babble ☯ 13:09, 2 July 2013 (UTC)

Earworm is a calque from the German Ohrwurm. Aaadddaaammm (talk) 06:01, 3 July 2013 (UTC)

There's more discussion on the word here. I've now added it at List of calques. Ghmyrtle (talk) 07:52, 3 July 2013 (UTC)

Dark matter/energy

Hi I've been listening to a few lectures and debates by Professor Lawrence Krauss and find him a fascinating and progressive champion of science. Is he highly regarded as a scientist (possible Nobel material) or does he fall into the category of celebrity scientists? In more than one of his lectures, he mentioned that ordinary matter comprises only 1% of the universe with everything else comprised of about 30% dark matter and about 70% dark energy. He proudly calls us cosmic pollution and says repeatedly that we are more insignificant than we think! Now, the dark matter article disagrees and says that ordinary matter is 4.9%. Who is correct? Is there more than one school of thought in how the mass-energy of the universe is measured? Sandman30s (talk) 07:51, 2 July 2013 (UTC)

It's hard to say exactly - but it seems that Krauss is one of a fairly typical group of older scientists who have passed their prime years of doing cutting edge research work and are motivated to move towards "popular science" - explaining this often confusing world to the general public. That's actually not such a terrible thing, we need people who actually understand this stuff to pass it on in a more digestible form! But that likely indicates that he won't be doing work at the Nobel Prize level anymore. That said, there is often a long delay between some great contribution and the recognition of a Nobel - and his early promotion of the idea of dark matter/energy could become sufficiently notable if/when we finally understand what all of that stuff actually is. So while I think it's unlikely, the Nobel committee can be capricious and nothing is impossible.

As for the percentages of dark matter/energy versus regular matter/energy - this is a field of rapid change, and accurate observations are difficult - so we shouldn't be surprised at seeing differences like this. The overwhelming message that "dark" stuff by far outweighs the matter and energy that we're familiar with is unchanged - so rather than ask why there is such a large disparity between 1% and 4.9% of ordinary matter - consider the fairly firm agreement that 95 to 99% of everything isn't ordinary stuff! SteveBaker (talk) 14:18, 2 July 2013 (UTC)

Thanks! This insignificant clump of stardust thinks that that is a good point... Sandman30s (talk) 19:56, 2 July 2013 (UTC)

Actually, accurate observations are not difficult, now that Planck (satellite) has mapped out the entire CMB. The fraction that ordinary (baryonic) matter takes up out of the universe's energy density is known as the baryon density, which, according to this article, is 4.56% with an uncertainty of 0.16%. That figure is from WMAP, which launched over 12 years ago. The newer Planck data gives around 4.9%. If Krauss really did say 1% (I've never heard him make such a claim), and you're sure he was referring to the baryon density, his claim is wildly inaccurate. --Bowlhover (talk) 23:28, 3 July 2013 (UTC)

It will take some effort to find the youtube links and exact times within them, but I can do so if you're interested. He never mentioned the word baryon as far as I can remember, but mentioned 'all stuff that you can see, including you and me and the earth and moon and stars etc.' - so very layman words implying that everything observable by us amounts to only 1%. I thought I was mistaken until I heard the figure twice. Sandman30s (talk) 12:22, 4 July 2013 (UTC)

citation counts: most cited people

Do we have somewhere a list of people ordered by the number of citations they draw (I mean "cites" that other people use when writing articles / books)? I am wondering if anyone keeps counts, at least for the ~10 most respected scientific publications (but to be honest I would be interested in any study provided they explain what counts and what doesn't. --Lgriot (talk) 08:50, 2 July 2013 (UTC)

I don't know if Wikipedia has a list, but you'll find plenty of sources online with opinions. How you count citations can make a difference. But in general the most cited scientists are those who developed widely used methods. It's easier to measure the citations to a single paper, and for some authors the number is simply staggering. Protein measurement with the Folin phenol reagent by Oliver H. Lowry has been cited about a quarter of million times, making this paper probably the most cited scientific work ever. You can see a few more examples at this article. That's from the 80s, so the numbers have drifted quite a bit since them, but those papers are still getting thousands of new citations every year, and I suspect they remain the most cited scientific works ever. Someguy1221 (talk) 08:59, 2 July 2013 (UTC)

Is there like a re-count every year by some organisation? And posted on the web for everyone to see? Googling "citation count" takes you google scholar citations gadget, but they say on that page it currently doesn't work, and I agree, I typed "Dawkins" in the author and got 0 citations as a result. --Lgriot (talk) 09:20, 2 July 2013 (UTC)

For scientific citations, Google Scholar does indeed work (although Google has a fairly expanded view of what counts as a scientific citation). For authors, check the "Author Search" feature. Dawkins is here, with a bit over 40000 citations. This only seems to work for authors that have some kind of profile, however. Noam Chomsky beats Dawkins hands down only counting the first page of results, but he has no author profile. Stephen Hawking is covered, with ~810000 citations. --Stephan Schulz (talk) 09:42, 2 July 2013 (UTC)

Thanks a lot, Mr Schulz, I was using it wrongly.--Lgriot (talk) 13:41, 2 July 2013 (UTC)

Resources described here may be helpful, too. -- Scray (talk) 14:56, 2 July 2013 (UTC)

Charles Murray's Human Accomplishment addresses this topic on a worldwide basis, giving statistics for work done up to 1950. I am fairly certain Newton comes in first place. μηδείς (talk) 22:05, 2 July 2013 (UTC)

"Physical" dark matter chunks near Earth?

There's been discussion of dark matter around here for some time [6] ; meanwhile, more "dark matter galaxies" are being announced or suspected: [7] [8]

Now, I understand there are many models of dark matter which represent it as hot, fast-moving, even non-self-interacting, so that it doesn't form physical "chunks". Still, I thought I should ask: how much can we currently restrict that model based on what has been observed? I assume we can't absolutely rule it out (assuming more than one kind of dark matter may exist) but we could limit the amount that is possible?

In other words, I suppose if you had a "dark matter planet" that went through or even near the Earth, we'd really find out about it due to tidal effects. If a "dark matter asteroid" is possible it would presumably make anomalies in satellite motion. And "dark matter stars" ought to leave other suns circling without a visible reason. I assume someone has looked for the limits of such evidences?

A particular scenario that appeals to me is a supernova remnant, which is often asymmetrical, shooting a remnant off into space at high speed. Presumably any dark matter that it gobbled up during life should remain gravitationally bound at the point of origin, right? So... does anything turn out to be perturbing the gas remaining at that point? Wnt (talk) 15:35, 2 July 2013 (UTC)

The strongest limits on this come from gravitational lensing, see e.g. here. Count Iblis (talk) 16:49, 2 July 2013 (UTC)

To form small clumps you'd really need the dark matter to interact with itself or ordinary matter so it could be slowed down. Otherwise a particle just speeds up towards a centre of mass, then goes round and away again like a comet. Random whizzing around can clump under gravitation to give a cloud but it won't lead to small chunks like stars (well not unless it is dense enough to start forming black holes). Dmcq (talk) 08:52, 3 July 2013 (UTC)

There is no scientific evidence for "dark matter". --Kharon (talk) 21:14, 3 July 2013 (UTC)

Well, the reason why I mentioned the supernova was that I figured, even if dark matter doesn't self-interact under any circumstance but gravity, it should still sink to the core of the supernova and then remain gravitationally bound after it blows apart. Unless the stuff is so "hot" (?) that it "evaporates" right out of the gravity well anyway?

(to clarify, I'm not so clear on this: even if the dark matter collides with nothing, including itself, shouldn't the orbital mechanics of the matter eventually lead to some particles being flung out to infinity while others lose speed and remain permanently within the growing star during the billions of years leading up to the supernova?) Wnt (talk) 22:14, 3 July 2013 (UTC)

There are no orbital mechanics left in the common inbetween dimensions of astronomical distances between stars and Star systems. If one would calculate the Relation between space "filled" by matter and space containing nothing you would find some very oddly tiny result. Same with distance. Pluto is ~4 Light Hours away from our Sun. The next star Alpha Centauri is around 35 000 Light Hours away (and astronomical concidered "near"). --Kharon (talk) 00:14, 4 July 2013 (UTC)

Interaction should in principle lead to kinetic energy redistribution in terms of a thermal model, though the time scale might be huge, especially if the interaction is weak. The average kinetic energy of the chunks relative to some gravitational picture would probably be key. In effect, small particles should behave as a gas, and if the initial average temperature is more than a few K, unless there is a mechanism (e.g. radiative) extracting energy from them collectively, they would presumably never coalesce into anything more dense than "clouds" – in the case of primordial hydrogen, electromagnetic radiation must have been crucial in the formation into galaxies and stars. Weak interaction with normal matter at the atomic level might lead to some extraction of energy, and to reduction of the local temperature, and hence some clumping. One supposition/model I've seen (a public lecture by an astrophysicist) gives local dark matter density going by a simple power law around centres (i.e. not within a start, but inside and extending out from it, like an atomic 1s orbital), but it was not clear what the minimum size was – a star? a galaxy? In any event, such cooled clumps of gravitationally bound dark matter seem to be a serious consideration, but if significant clumping occurred at the level of stars, we should have had abundant evidence of it from planetary orbital observations. — Quondum 11:12, 4 July 2013 (UTC)

What's the sourest object in the known universe?

Any ideas? Just a question that occurred to me when eating one of those super-sour Toxic Waste sweets recently. I do seem to recall that something was once announced as the most foul-smelling object in the known universe... --Kurt Shaped Box (talk) 20:53, 2 July 2013 (UTC)

If sourness is the sensation of acidity, fluoroantimonic acid is at the top of superacids. Theoretically if you could eat a spoonful of protons those would be the most acidic thing there can be. Sorry for how the dull the answer is... 88.112.41.6 (talk) 21:08, 2 July 2013 (UTC)

If sourness is ability to donate protons then you probably can't go past ionized hydrogen, and there is plenty of that in the universe. Graeme Bartlett (talk) 21:18, 2 July 2013 (UTC)

I started wondering what would happen if you had pure protons at an everyday life density. Say a spoonful of water and instantaneously remove all the oxygen nuclei and electrons. Those protons wouldn't like to be close to each other due to electrical repulsion, would they? Would that be minor heating of the spoon or a big-hole-in-the-ground event? 88.112.41.6 (talk) 21:58, 2 July 2013 (UTC)

It is impractical to remove the electrons - the coulomb force is amazingly strong, and you'd have to expend a lot of work to separate the electric charges. So, in your scenario, a necessary condition is an input of a huge amount of energy to dissociate (and then separate) the ions and electrons. As a result, you'd have a very hot ionized mass of hydrogen. You can easily calculate how hot you need to get to ionize the hydrogen: it's the ionization energy divided by the heat capacity. (!!). Accounting for adiabatic expansion which is reasonable when you compare the time-constant of the expansion to the effective rate of heat exchange with the outside air, I think you'll find it hard to keep the resulting explosion contained in a spoon-heap-sized volume! Nimur (talk) 22:30, 2 July 2013 (UTC)

An Assistant-Principal at a school I once taught at was a really sour old b.... HiLo48 (talk) 23:34, 2 July 2013 (UTC)

Perhaps, you mean "sourest non-toxic substance"? Plasmic Physics (talk) 02:29, 3 July 2013 (UTC)

One should take care that one is dealing with the correct concept. "Sourness" might relate to hydronium concentration rather than proton donation. — Quondum 03:03, 3 July 2013 (UTC)

Something is wrong with the magnetic induction " B" !

When we analize the interaction between two current carying conductors we first represent the magnetic induction "B" following the right hand rule. But, if you look back at the origine of this representation you can find that it comes from Faraday and the orientation of the magnetic induction "B" was based on the pattern of iron filings formed around a magnet bar which resemble to " field of lines" conneting the two poles. If you look closer the iron piling particles also can be considered tini magnets and their orientation will always be that their internal atomic currents that creates their magnetic field will be aligned with the internal atomic currents of the large permanent magnet bar so they will tend to have the same direction ! The independent "lines" are formed because the adjacent particles of iron will align their internal currents with the stronger current of the large permanent magnet bar while between the "lines" there will be repulsion, also particle of iron from a "line" will form chains with the top and the bottom particle so that their internal currents will be aligned too. So now from the two parallel electric current situation we arrive to another two parallel electric current situation! And the real magnetic field looks more like "something" that is allong the lenght of the conductor. Think about two ships on water that moves parallel to each other in the same direction. Because of Bernoulli effect the ships will be drawn together, but if they move in opposite directions they will be pushed away from each other...The same it seems to be with the magnetic field too. There is no such a thing like magnetic induction "B" that is tangent to the conductors or circle the conductor...its just an illusion ! Can you see the error? — Preceding unsigned comment added by 71.185.132.57 (talk • contribs)

Yes, your error is that you are confusing magnetic field with magnetic induction. These terms refer to distinct physical entities. If you use terminology differently from everyone else, you won't be able to understand the commonplace explanations. Magnetism obeys simple rules that have been experimentally tested and verified with increasing accuracy for around two centuries; if something was catastrophically wrong with our understanding, we would all have noticed! Nimur (talk) 21:17, 2 July 2013 (UTC)

I think that you are confusing "magnetic induction B" which is also called "magnetic field" (read wikipedia :) with "electromagnetic induction" ... Saying that " magnetism obeys simple rules" its a very superficial statement, anyway.

I noticed our disambiguation page - I read Wikipedia - and many other things - quite extensively! I'll go out on a limb here and say "usage of the term 'magnetic induction' to refer to the magnetic field is incorrect and should be eliminated from the disambiguation page." I had no prior recollection of ever hearing the term "magnetic induction" abused this way. In deference to my limited knowledge, I referenced two university-level textbooks on electrodynamics that I keep handy next to my bed for just such situations. Tipler's Physics for Scientists and Engineers gives a great description of the history of the magnetic field, and carries a full chapter titled "magnetic induction." Magnetic induction is defined as the process by which "emfs and currents are caused by changing magnetic fields..." Nowhere in the chapter, nor in the convenient glossary, does this text use the term "induction" to refer to the field.

David J. Griffiths' "Introduction to Electrodynamics", §6.3, has a special note on the topic, while discussing fields in materials, and I quote: “Many authors call H, not B, the "magnetic field." Then they have to invent a new word for B: the "flux density," or magnetic "induction" (an absurd choice, since that term already has at least two other meanings in electrodynamics). Anyway, B is indisputably the fundamental quantity, so (Griffiths) shall continue to call it the "magnetic field," as everyone does in the spoken language.” I guess this scores a point for the OP - the term is used somewhere. But not in modern textbook-definition usage. A further note, in my edition: “For those who disagree, (Griffiths) quotes A. Sommerfeld's Electrodynamics (1952)... "The unhappy term 'magnetic field' for H should be avoided as far as possible. It seems to us that this term has led into error none less than Maxwell himself" ...“

I was willing to entertain the notion that the terminology is a foreign-ism, or archaic (... it would not be the first time I encounter unfamiliar physics lingo, only to discover that all students in, say, Ghana or India use different terminology than I do). So I went straight to my digital copy of "Experimental Researches in Electricity," (which is available free online) to refresh my memory - I never recalled its author using the term "magnetic induction" incorrectly! Michael Faraday uses terminology in a way I would agree with; "magnetic induction" is described as the process of inducing a current using a changing magnetic field, and never to refer to the magnetic field itself. So, I know of no historical or archaic usage, but this was arguably a very short literature survey. Based on Sommerfeld's comments, Maxwell may be the source of the original terminology confusion; I'll probably dig up some Maxwell writings for my own entertainment, but I don't usually find those very enjoyable to read, because his writing style is confusing.

I hope if nothing else comes from these references, you'll have some good reading suggestions to help clarify the topic. Griffiths' chapter on magnetism and its interaction with magnetized materials is excellent and may clear up your original question. If nothing else, it may dispel any rumors that I make flippant or superficial contributions! Nimur (talk) 11:24, 3 July 2013 (UTC)

For anyone who is still waiting on the edge of their seat for the startling conclusion: it was in fact Maxwell who first used the term 'induction' in this way, in A Treatise on Electricity and Magnetism, Part 3, Chapter 2, Magnetic Force and Magnetic Induction. I will not be the first, nor the last, physicist to say that Maxwell's writing-style and choice of terminology was not very clear, and it certainly deviates from modern terminology. Nimur (talk) 18:07, 4 July 2013 (UTC)

July 3

Bluejays and cardinals

How are bluejays and cardinals related evolutionarily? Do they share a common ancestor? What is their recent most common ancestor? Also, is it legal in the United States to capture a SMALL wild animal like a blue jay or cardinal and keep it as a pet or as dinner, or would a person need a license no matter what? Sneazy (talk) 01:15, 3 July 2013 (UTC)

The easiest way for you to see how two organisms are related is to check the infoboxes in their articles. If you look at Cardinal, you will see: its kingdom is Animalia, phylum Chordata, class Aves, order Passeriformes, family Carinalidae, genus Cardinalis, and species Cardinalis cardinalis. Looking at Blue Jay, its kingdom is Animalia, phylum Chordata, class Aves, order Passeriformes, family Corvidae, genus Cyanocitta, and species Cyanocitta crostata. So the two are identical in descent down to the level of order: both are passerine. They differ at the family level, with the Blue Jay being a corvid.

The legality of capturing, killing, or eating wildlife varies by jurisdiction, and in any case, we don't offer that sort of legal advice. - Nunh-huh 01:36, 3 July 2013 (UTC)

Indeed, but see Migratory Bird Treaty Act of 1918. Matt Deres (talk) 01:44, 3 July 2013 (UTC)

@Nunh-huh: Having written an undergraduate research paper on the evolution of a specific type of passerine birds, the lyrebirds, I am not sure what you are trying to imply in your post. All organisms interact on a species level. Although the hierarchical classification system is useful in taxonomy, it does little to answer the question of how bluejays and cardinals evolved from ancestral passerine birds. Sneazy (talk) 02:58, 3 July 2013 (UTC)

Your question contains no indication that you understood that both species were passerine birds; I was simply pointing you towards that information. You didn't ask how blue jays and cardinals evolved from ancestral passerine birds, you ask if they had a common ancestor. - Nunh-huh 22:06, 3 July 2013 (UTC)

Well, I was expecting a much more fuller answer. You know, one that has more substance. :P Sneazy (talk) 00:09, 4 July 2013 (UTC)

You got what the question merited. You're welcome. - Nunh-huh 00:37, 4 July 2013 (UTC)

No, I didn't. The recent most common ancestor can't be a broad category. Saying that blue jays and cardinals derive from passerine birds is like saying humans derive from the apes. It's not specific. So, I didn't get what the question merited. A better response would be to list an ancient passerine bird species that gave rise to the blue jay and the cardinal. Sneazy (talk) 18:37, 4 July 2013 (UTC)

• They are not at all close within the passerines. Jays are quite close to crows within the crow superfamily. Cardinals are close to sparrows in the sparrow superfamily. (Search for cardinal and jay in our passerine article) Keeping a Northern Cardinal can get you a fine due to the Migratory Bird Treaty Act of 1918. If you want to keep a bluejay you will deserve whatever you get. I would love to see a hybrid, however unlikely. μηδείς (talk) 03:15, 3 July 2013 (UTC)

1. Where did you get that knowledge?

2. It still does not explain how the two types of birds might have evolved or what might the specific selective forces be. Sneazy (talk) 03:32, 3 July 2013 (UTC)

That second question is very interesting, because as far as I am aware, "what might the specific selective forces be" is very rarely known, am I right? They are too many factors, and we haven't collected the data for most species. But maybe someone with better understanding of the science will correct me, and I will be very happy to hear what they have to say. --Lgriot (talk) 08:32, 3 July 2013 (UTC)

1) look at the article Passerine and the position of the corvidae and the cardinalidae within the taxonomy. (2) requires a treatise, μηδείς (talk) 16:33, 3 July 2013 (UTC)

Total solar eclipse of Egypt circa 3100 BC?

Is there some way to calculate when, if ever, one of these occurred over Egypt around about this period? Also, I understand that a total eclipse is relatively rare (recurring only 375 years or so according to this source) - does this value fluctuate depending on ones position on the globe? 70.112.97.77 (talk)

One important distinction is whether you mean a total solar eclipse at one particular point (which is rare) or anywhere on Earth (which is fairly common). That is, each eclipse is normally only a total eclipse for a small portion of the Earth (if anywhere at all), with the rest seeing either a partial eclipse or no eclipse at all (including the half of the Earth in night at the time). StuRat (talk) 03:00, 3 July 2013 (UTC)

here is NASA's list of total eclipses for 3999-3000BC, with lat and long coordinates. Cairo is near 30N, 30E. MChesterMC (talk) 08:20, 3 July 2013 (UTC)

Okay, so it looks like no total solar eclipses for that region around that time. Thanks for the help! 70.112.97.77 (talk) 18:35, 4 July 2013 (UTC)

NYC and nuclear attack

If, in the 1960s the Soviet Union decided to attack a city like New York with nuclear weapons, how long would humans have to wait before the city is safe enough to re-enter without threats of radiation poisoning? Thanks. 64.229.207.42 (talk) 03:06, 3 July 2013 (UTC)

It would depend on the bomb and how delivered . Hiroshima and Nagasaki are habitable now and have been for some time. μηδείς (talk) 03:18, 3 July 2013 (UTC)

The thing with radiation is that it doesn't just completely disappear some day. Instead it gradually reduces in magnitude. So, when exactly it is "safe to return" is debatable. Also, you said "radiation poisoning", which requires a fairly high level of radiation. Lower levels continue to cause an increased incidence of cancer for years to follow. StuRat (talk) 03:19, 3 July 2013 (UTC)

Also, there tend to be "hot spots" remaining where the fallout dust and debris has collected for one reason or another - and those places remain more dangerously radioactive for longer. Other issues are that the primary radiation from the bomb can make other materials radioactive - and the half-lives of those materials is wildly variable.

As StuRat points out, radioactive decay isn't an all-or-nothing thing. If the particular radioactive isotope left behind by the explosion has a half-life of a year, then the radiation levels will halve every year from then on...but there is (essentially) never a day when there is no radioactivity left - and any amount of radiation increases your lifetime cancer risk. After the Chernobyl reactor disaster, people halfway around the world and three decades later still have a small increased cancer risk because of it. It's estimated that even 80 years after that explosion, your personal risk of getting thyroid cancer will be 0.3% higher than it otherwise would have been - solely because of that accident.

SteveBaker (talk) 20:38, 3 July 2013 (UTC)

Would depend largely on weather conditions as land contamination from a nuclear bomb would be caused mostly thru Nuclear fallout, not directly as most wrongly asume. --Kharon (talk) 21:02, 3 July 2013 (UTC)

There are a lot of variables. For one thing, if it was an attack in the 1960's then New York would have been out of range of soviet missiles. The bombs would have been delivered in the secondary attacks by aircraft. These would most likely have carried 'city busters'. To put it another way, very large hydrogen bombs of many megatons. The initiation hight of such bombs (limited by high the delivery aircraft could fly) would probable get graded as a 'ground burst'. In other word, a third or more of the fire ball would make contact with the ground. In this scenario, a great deal of fall out is produced -measuring many hundreds of rads. I don't have references to hand but your looking at two months before a short sojourn into the area could be safely attempted (longer, if you are going by modern standards of allowable exposer rates) . The Hiroshima and Nagasaki bombs were both air bursts. Therefore, after about an hour, the radiation had decayed enough, not to cause any short term hazard. Those, that put their cancers down to entering Hiroshima the day after are most likely grasping at straws. --Aspro (talk) 23:18, 3 July 2013 (UTC)

Are you sure that New York would have been out of range of Soviet missiles? What of those medium-range missiles in Cuba? Or, for that matter, what of submarine-launched missiles? 24.23.196.85 (talk) 00:55, 4 July 2013 (UTC)

Indeed, Russian Submarines had the technology to do it according to our article: "the Soviet Union made its first successful underwater launch of a submarine ballistic missile in the White Sea on 10 September 1960", unless there is a claim that these misslies could not carry a nuclear warhead. So from that date on, New York was never out of range. --Lgriot (talk) 08:03, 4 July 2013 (UTC)

The article on the Chernobyl disaster has quite a bit about the ongoing effects of radioactive contamination, including guesstimates of timescales for the area to become safe. Astronaut (talk) 18:34, 4 July 2013 (UTC)

Bipolar Disorder associated features

Hi guys,

My post is related to bipolar disorder.

I am curious as to what features exist characteristic of bipolar disorder, particularly any features that are exclusive to the disorder. For instance, I am aware of ideas of reference as a feature of psychotic mania. Another example might be the connection between creativity and bipolar.

Are there any other major or minor examples of associated features (AF) of bipolar disorder that could be added to the current page on AF? (Second link)

Thanks! I have a personal interest in this as I am a 19 y/o male recently diagnosed with bipolar.

Jeremy

GRHooked (talk) 09:37, 3 July 2013 (UTC)

Have you looked at our article on hypomania? Looie496 (talk) 14:53, 3 July 2013 (UTC)

Remember that bipolar disorder is something of a spectrum, so you may want to check out spectrum disorder and Bipolar_spectrum#Bipolar_spectrum. You may therefore have trouble finding things exclusive to the condition, except in extreme cases. IBE (talk) 03:48, 4 July 2013 (UTC)

Rehydration of troops in Iraq/ Afghanistan

Hi,

After having watched Jarhead, and also talking to troops that have served in Iraq/Afhanistan, it seems like good hydration is a massive part of serving there. Since a lot of the troops come from colder areas where less water is lost from sweat, this could cause a problem with troops not being used to drinking so much water so often, since they must sweat buckets under the "perfect storm" of hot weather, stress and heavy exercise. Did the US/ other countries have a way of preparing the troops before they went or while they were there to get troops used to drinking so much water (other than rehydration tablets). If so what did it entail? Obviously they just got them to drink a lot very often, but was there a particular regime they followed? 80.254.147.164 (talk) 11:47, 3 July 2013 (UTC)

You don't need training to know when you're thirsty and to take water then. Those drinks companies telling people they need to hydrate when they are not thirsty are a menace, drinking too much fluid is far more of a danger than mild dehydration. See water intoxication. Dmcq (talk) 12:28, 3 July 2013 (UTC)

Yes, I agree that for most it's pretty easy and unessecary to drink when not thirsty. But if you are in such a difficult environment where you are unsure when the next time you will be able to drink is, or when the next time that they will have to run for 3 miles in heavy gear will be, you might need a disciplined approach to keep yourself topped up, or at least repetition to get yourself in the habit. How much water does each soldier take on patrol? Or is water freely available enough that they can obtain bottles fairly easily? 80.254.147.164 (talk) 13:19, 3 July 2013 (UTC)

Three miles in kit? Human Mammal, Human Hunter - Attenborough is a clip showing a man run down and kill a kudu over eight hours during the heat of the day in the Kalahari desert. Persistence hunting is thought to be one of the first human adaptations. Dmcq (talk) 13:45, 3 July 2013 (UTC)

I saw that show - but the guy was nearly naked - and almost completely unencumbered with equipment. He wasn't dressed in battledress, bulletproof vest, with a helmet and a 100lb pack on his back. Also, he had been adapted to the environment since birth rather than coming from someplace where the temperatures never get over 90F - and he was under much less stress because there weren't potentially snipers and IED's around every corner. It's not a remotely comparable situation. SteveBaker (talk) 16:58, 3 July 2013 (UTC)

• The following is OR but I have some confidence in it. I lived for 20 years in Tucson and did a lot of desert hiking in Afghanistan-like conditions, needing to drink literally gallons of water a day (actually Gatorade or even lukewarm ice-tea are better than plain water, but whatever). My experience is that the ability of the body to process that much water develops over time. Early in the hot season I would find it difficult to drink as much as I needed (there's a sort of sick feeling), but after a few hikes I could handle a lot more. I also did many hikes with visitors from colder places, and found that they had a lot more difficulty handling the heat than I did. Looie496 (talk) 17:12, 3 July 2013 (UTC)

You probably were able to sweat properly. The problem with wearing an army uniform with bulletproof vest etc is not being able to sweat properly. I believe they try and use materials that wick the sweat away but heat stroke is a real possibility if they can't keep their temperature down. A place with high humidity now, they can be quite unpleasant, you just lie there waiting for it to get cooler. Dmcq (talk) 18:12, 3 July 2013 (UTC)

Something especially nasty happens when the air temperatures get above body temperature (we had three 106 degF days here in Texas last week - so I speak with some authority!) Normally, when the temperatures are more sane, your body creates a volume of warm air around it - an effect which clothing accentuates by trapping that air. Removing clothing and having a nice breeze helps that warm air to be moved away from you - so you feel cooler. That's why fans work - they don't cool the air - they just let you feel the true ambient temperature. However, when the ambient temperature gets above body temp, all of this goes horribly wrong - because you're replacing body temperature air with hotter air - and that makes matters worse. A "cool breeze" becomes more like opening an oven door!

Moving air around still helps a little bit though because the only way you can lose heat under those circumstances is by sweating and letting the evaporating water carry the heat away. But if you gradually build up a layer of humid air around your skin, that slows down the evaporation rate - so a gentle breeze still helps to some degree by reducing the humidity close to your skin. The idea behind wearing seemingly warm clothing in hot weather is to prevent that higher-than-body-temperature air from reaching you - but it needs to be made so as to allow sweat to wick away and evaporate on the outside of the clothing in order to avoid humidity build-up. This ends up being a tricky business.

If humidity is close to 100% and temperatures are over body heat, then you have a really dangerous situation. Sweat doesn't evaporate because of the 100% humidity - and breezes only make you hotter - so there is really nothing to keep your body temperature reasonable. At that point, the only thing you can reasonably do is to keep heat-generating activities to a minimum and hope that the temperature drops before you die from it.

SteveBaker (talk) 20:20, 3 July 2013 (UTC)

There are sources to be found about this. I searched "soldiers afghanistan hydration rules" and came up with [9] on the first page. This really isn't my field, and some of the considerations involved in deciding on these protocols are likely not obvious. Wnt (talk) 22:11, 3 July 2013 (UTC)

Surely it's worth remembering now, as the leaders of the countries involved recently seemed to forget, that people from cold places have tried to invade these places many times before, going back at least a hundred and fifty years, and probably much longer. Britain and Russia come to mind. Their soldiers would not have had access to modern re-hydrating drinks, nor almost certainly to the mere quantities of fluids available to participants today. I don't know how they coped, but I often wonder about it. HiLo48 (talk) 22:20, 3 July 2013 (UTC)

We're the same species and most people have little difficulty in acclimatizing to hot weather and humans evolved in such conditions long before the idea of re-hydrating drinks was oversold. Dmcq (talk) 23:47, 3 July 2013 (UTC)

Yes, but as I already explained, these people are running around in bullet proof vests, combat fatigues, helmets and 100lb packs...we evolved for exercising in not much more than a spear and a loincloth. This kind of abuse of the body requires special intervention. SteveBaker (talk) 03:10, 4 July 2013 (UTC)

I was answering HiLo48's question just above. The document that Wnt just above that again pointed at gives the answer about the soldiers nowadays. They have good answers in that though they still seem to talk more in terms of dehydration rather than heat stress. They still buy into what the drinks companies say to some extent though they have cut down on the recommended water because of the casualties from water intoxication. Dmcq (talk) 08:24, 4 July 2013 (UTC)

July 4

Colds and bacterial infections

Why do many bacterial infections occur at the same time as or straight after a cold and vice versa? Is it just because the immune system is weakened? Clover345 (talk) 12:14, 4 July 2013 (UTC)

It's a myth that these secondary bacterial infections are commonplace: This document says that: "The common cold rarely leads to secondary bacterial infections that require antibiotic treatment." - couldn't find details of why secondary infections happen though. SteveBaker (talk) 14:04, 4 July 2013 (UTC)

Boiling water in a kettle

Which would use more energy? 1) Boiling 500ml of water from room temperature and repeating; or 2) Boiling 1 litre from room temperature. Thanks. 163.202.48.125 (talk) 13:05, 4 July 2013 (UTC)

This has the appearance of a homework question, and our policy is not to do people's homework for them. Looie496 (talk) 13:10, 4 July 2013 (UTC)

In a real-life scenario or in a imaginable scenario where you don't have to heat the pot and this doesn't lose heat at all (that means, all heat gets transfered directly to the water without loss)? Try to think about the first case, what would be more efficient? OsmanRF34 (talk) 13:20, 4 July 2013 (UTC)

I guess I'm flattered you think this is homework - it means I phrased the question well. It is not homework - I don't do homework since I'm not in school. And I'm talking about a real life scenario. So I boil 500ml and then boil another 500ml immediately after (I suppose it matters if I wait before boiling the second one) OR I just boil the 1 litre. 163.202.48.125 (talk) 13:29, 4 July 2013 (UTC)

I don't believe homework questions are well worded or well conceived. Normally, they try to exclude lots of constrains that matter in real-life and somehow have hints to the answer desired. OsmanRF34 (talk) 14:31, 4 July 2013 (UTC)

If your kettle is large enough to boil one liter at once, it's almost certainly more efficient to do it in one go. Your heat loss into the environment is a function of temperature and surface area, and with two times 500 ml, you will still have the same surface of the kettle that heats up and loses energy, and you also have a larger water surface. But you should be able to find out with a simple experiment. Just do it and time it. Standard electric kettles are either on or off (and you can hear/see when they auto-shut-off activates), so energy use is (modulo very small effects) directly proportional to time. --Stephan Schulz (talk) 13:52, 4 July 2013 (UTC)

Thanks, Stephan! I didn't think of that experiment. Does that mean that the amount of current passing through those heating rods in the kettle is the same as long as the kettle is switched on? 163.202.48.125 (talk) 15:25, 4 July 2013 (UTC)

Yes, a standard kettle will have a nearly constant current draw (when the coils heat up, resistance goes up a little bit, but that is a very minor and transient effect). Since resistance is nearly constant, and Voltage is constant (modulo brownouts ;-), the kettle will always draw nearly the same current, and use nearly the same power. --Stephan Schulz (talk) 17:02, 4 July 2013 (UTC)

Also, if your concerned about efficiency, boil it with a lid of some kind on it. It should come to a boil faster than if it's open to the air. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:23, 4 July 2013 (UTC)

Putting an aspirin on the gum

Some people put an aspirin on the gum when they have toothache, is this practice backed by any publication? It's clear that even our skin would absorb some chemicals placed on it, but would the gum absorb even more? OsmanRF34 (talk) 13:28, 4 July 2013 (UTC)

Google works. --Jayron32 14:07, 4 July 2013 (UTC)

This link from that same google search states "but never put aspirin against the gums near the toothache, as this may burn the gum tissue". --Jayron32 18:34, 4 July 2013 (UTC)

It works in what sense? It outputs lots of 'natural remedies' results, unrelated results like gum aspirin, and relevant results for someone searching for a topical aspirin or aspirin gel, but I was asking for the usability of a normal aspirin on the gum. OsmanRF34 (talk) 14:26, 4 July 2013 (UTC)

Individual reactions to aspirin can vary. Some cannot ingest it, due to its tendency to inflame the stomach lining. It can also act as a blood thinner, which you may not want. If you've got a recurring toothache, you should see a dentist. ←Baseball Bugs ^{What's up, Doc?} carrots→ 15:20, 4 July 2013 (UTC)

wild animals and spicy food

Do any animals in the wild have a taste for spicy plants such as hot peppers, mustard-type plants and horseradish, ginger, onions, garlic, etc? Or do they all avoid these plants because they are an irritant?— Preceding unsigned comment added by 176.251.188.16 (talk • contribs)

I don't have a source on this because I read it a long time ago, but although they don't have a taste for it per se, birds are unaffected by spicyness. I read it in a book about leaving out stuff for birds to eat; coat it in spicyness to keep mammallian scavengers away, but the birds won't even notice. 176.251.188.16 (talk) 15:19, 4 July 2013 (UTC)

We hear about "grain fed cattle" as the common type and "grass-fed beef" as a pricy gourmet choice, but cows are happy to eat onions and garlic if they find them, though the milk then tastes of onion and garlic. Mad scientists are experimenting with feeding garlic to cows to reduce cow-flatulence which supposedly causes global warming: [10]. Cows will eat so much onions that they can get sick and even die. Horses and goats eat onions too: [11]. Cows do not immediately eat turnips growing in a field, but learn to like them, especially after freezing weather has increased the sugar content of the tops. This source also implies they will eat radishes: [12]. Comments at this site suggest that turkeys and parrots love very hot peppers, but deer avoid them. Here's a video of a cow eating pickles and hot peppers. Edison (talk) 16:00, 4 July 2013 (UTC)

Birds and primates will eat hot foods. Spicy foods often have attractive red colors visible to trichromatic birds and mammals. Dogs and cats and hooved mammals are neither attracted by their colors nor adapted to eat spicy foods, which may be poisonous. Humans have large livers adapted to handling plant alkaloids and so forth. μηδείς (talk) 17:34, 4 July 2013 (UTC)

The link above mentions this, but for those who haven't clicked it, one of the reasons birds ead "spicy" peppers is because they don't sense capsaicin like humans and other mammals do. So when a bird eats a habanero, it's not really percieving any spicyness - for the bird it's somewhat akin to a human eating a bell pepper. So it would be misleading to say that birds eating spicy peppers indicates that they like spicy food, because to them it's not spicy. -- 71.35.96.251 (talk) 18:56, 4 July 2013 (UTC)