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March 29

Bedbugs: Is there speculation among scientists about possible benefits to humans of bedbugs?

I was thinking that maybe bedbugs reduce violent tendencies in people, because the decline and resurgence in bedbug numbers in United States roughly coincided with increase and decline in violent crime in USA. Of course i don't know for sure that would be a benefit in some kind of biological sense, but it would be an effect, and a benefit in a human values sense. I suppose it's a silly longshot question, but on the other hand there may (or may not) be some theoretical virtual certainty among biologists that a longtime parasite like bedbugs should by now have caused some kind of benefits and side effects, and I'm looking for some kind of notable fall and rise of a benefit coinciding with the fall and resurgence of bedbugs. Thanks, and thanks for your answers to the previous question.2601:7:6580:5E3:9440:CEA3:2200:C3CC (talk) 07:05, 29 March 2015 (UTC)

The only reason it would evolve to benefit humans would be if that would also benefit them. It's hard to see why that would be the case here. There is a cat feces virus which may do close to the opposite, though, by increasing risk taking behavior in humans. In this case it seems to be designed to do this in mice, so they get caught as prey and pass the virus on to their predators (one of which is cats). The effect on humans, if any, is just an accident. StuRat (talk) 07:22, 29 March 2015 (UTC)

It's true that bedbugs would be unlikely to evolve to help humans unless it helped them. But we humans may have evolved in some way that makes use of bedbugs. Or there may be just side effects that might or might not be biologically beneficial, but that we value.2601:7:6580:5E3:79CC:4600:8B68:8653 (talk) 06:25, 30 March 2015 (UTC)

StuRat appears to be writing about Toxoplasma gondii, which is not a virus, but an obligate, intracellular, parasitic protozoan. The effect on risk-taking in rodents is well documented (see links in article). Regarding humans, it is suspected but by no means proven. --NorwegianBlue ^talk 09:07, 29 March 2015 (UTC)

See cat lady. μηδείς (talk) 17:00, 29 March 2015 (UTC)

In your case, if the correlation is real, it's much more likely to a common cause - e.g. economic hardship leading to both violence and reduced hygiene . See Correlation does not imply causation. --Stephan Schulz (talk) 09:20, 29 March 2015 (UTC)

Actually that correlation would be backwards; see the OP's statement again. Perhaps you might hypothesize neurological effects from DDT. Or perhaps sociologically, the kind of fanatical enforcement mentality that effectively controls bedbugs has the less beneficial effect of causing a War on Drugs that drives up prices and crimes killed over territory. Who knows? It is very hard to do science of one-off events. Wnt (talk) 12:22, 29 March 2015 (UTC)

Can we classify this new theory a form of discourse analysis? (link provided below)

I am currently studying discourse analysis as a social science research method. While looking for some literature on the subject, I stumbled upon this scholarly article entitled “Discourse Analysis of Public Debates Using Corpus Linguistic Methodologies”. Generally, it argues for the use of computational methods to dissect and analyze public policy debates. Just taking glance at the article got me confused as to what discourse analysis is, as expounded by philosophers and social scientists. As I understood it, discourse analysis uses hermeneutical and qualitative methods to scrutinize the meanings and relations of different forms of communication. I wonder if this article discusses discourse analysis in paradigm similar to that developed by Foucault and other continental philosophers. Did it just borrow the term to discuss a new method that is different from discourse analysis? And, lastly, can we formalize discourse analysis without neglecting the intention of its makers?Rja2015 (talk) 14:41, 29 March 2015 (UTC)

You should start by reading our article on discourse analysis. You should then attempt to learn a little about quantitative discourse analysis/computational discourse analysis, which is one subdiscipline within the field. You are right that in its earlier forms discourse analysis was largely qualitative in its approaches, and much discourse analysis remains qualitative and interpretive. The development of computers and associated software capable of analysing large volumes of text or other communication, however, has allowed practitioners in the field to address one of the criticisms of discourse analysis - namely, that it relies too much on the personal interpretation of the text by a single practitioner. By specifying a set of rules in advance of any study of the text, and then applying these rules in performing the discourse analysis, the personal interpretation element is removed, and replaced by clear measurement. This approach works particularly naturally in conjunction with corpus linguistic approaches, since the tradition in corpus linguistics is largely experimental and (debates about annotation notwithstanding) attempts to minimise bias that might arise as a result of researcher interpretation. As you read the paper, you'll see how the researchers analyse the texts on the basis of word usage, with the vocabulary corpus being listed in e.g. Table II. I have to say, it's a really interesting paper.

As for your questions, I suggest you look at our article on Foucauldian discourse analysis to answer your first (inexplicit) question. I suspect you'll conclude that Foucault was primary concerned with issues such as power relationships, which are only one of a whole range of topics than can be examined through discourse analysis. I'm inclined to suspect that the authors of the paper were more concerned with vocabulary issues, which are relatively easy to quantify, than more complex and subtle issues of relative power. Computers aren't good at such subtleties (yet). For your second question, where you ask if this is a "new method", this question is clearly addressed on p.59 of the paper, in the paragraph beginning "Corpus is generally defined..." and its sequelae. The Austin the authors are referring to is J.L. Austin, whose work strongly supports the view that the best way to understand the meaning of a word is by examining its use. It is incumbent on you as a civilised human being to read his "How To Do Things With Words"; it's a foundational document of much current thinking in this area. The following paragraphs make a case that the paper's approach is consistent with earlier discourse analysis approaches, by emphasising that "corpus linguistics evaluate the ways of using language with actual data of language use". I think the authors see themselves as extending discourse analysis, rather than creating a new method (and, personally, I'd agree with them). As for your last question, I think the answer is that what the authors of this paper are seeking to do is perform a discourse analysis that focuses on vocabulary only. Recall that discourse analysis aims to examine every possible semiotic event. What the authors of this paper are seeking to do is simply to specify formal rules for one particular analysis, and examine the results. There's no larger attempt at formalisation going on. RomanSpa (talk) 18:40, 29 March 2015 (UTC)

Thank you, Roman Spa! Your answer is very informative. One more thing, I've read that critical theorist and critical discourse analysts are staunch anti-positivists. As such, they recognize the importance of their subjectivities and personal biases in emphasizing their involvement in their research. Do anti-positivists, such as critical discourse analysts, see formalization as antithetical to their position?Rja2015 (talk) 23:13, 29 March 2015 (UTC)

Healing

On the animated show the Simpsons, a kid touches a wound and the wound noticeably heals in only a few seconds and the scab thinks it needs to grow over the hand. A dumb throwaway gag sure, but is there any truth to this? If your thumb was dead still on a new scrape till next year what would happen? Hey, wait, if 2 brand new scrapes were put together and never move how would it know to grow 2 skins? 128.177.161.189 (talk) 22:21, 29 March 2015 (UTC)

It might help if you told us which Simpsons episode and when in the show (the minute) the clip appeared. Also, I am American, but find it impossible to figure out what you mean by "If your thumb was dead still on a new scrape till next year" and "if 2 brand new scrapes were put together and never move" means, and what it is in "how would it know to grow 2 skins?" Can you break this down into clearly expressed separate sentences? μηδείς (talk) 23:35, 29 March 2015 (UTC)

I don't know the answers, but I understand those sentences. "If your thumb was dead still on a new scrape till next year" means, if you have a scape and place your thumb on top of it, and hold it there without moving it for a year. "If 2 brand new scrapes were put together and never move" means, if you have a scrape on your body somewhere and another scrape on your thumb, and you place the scraped part of your thumb over the scraped part of your body and hold it there for a long time without moving it. Looie496 (talk) 00:17, 30 March 2015 (UTC)

Yes, that makes sense, but it is way off biologically. See human skin, dermis, and epidermis as well as wound healing. Basically, the scab is inert dead clotted blood that has hardened over a layer of skin where the epidermis has been rubbed/torn off. The basal dermal cells regenerate, producing new skin under the scab, which eventually falls off. In fact, all the outermost skin of the body falls off after a while, we just don't normally see the flakes, except that they constitute a large portion of the dust that accumulates in inhabited rooms. The scab itself plays no active living role, it serves solely to protect the regenerating tissue underneath. μηδείς (talk) 01:34, 30 March 2015 (UTC)

So, grafting not so easy. —Tamfang (talk) 05:49, 30 March 2015 (UTC)

As I understand it, wounded skin can grow together where it isn't supposed to. In fact, in female genital mutilation, I believe this is used to intentionally seal the labia shut. StuRat (talk) 06:02, 30 March 2015 (UTC)

It's also used in surgery when you want to cover an area with new skin, see Flap (surgery). Especially interesting in this context is the distant flap or Walking-stalk skin flap where skin from one part of the body is attached to another part of the body while also attached to the original part. Here's an old drawing as an example. You can find photos as well but they are rather disturbing. Sjö (talk) 06:32, 30 March 2015 (UTC)

Graftings like that are done "side to side" so to speak, where the two skin layers have the same orientation, like pulling together the opposite sides of a wound and stitching them together. Under normal circumstances if you had a scab on your thumbtip and fingertip and pinched them together, they would simply heal normally. μηδείς (talk) 18:16, 30 March 2015 (UTC)

You're speaking as though from authority. How do you know this to be true?

Are you aware of some known principal in medicine that you forgot to link? Or of a case where the experiment has been tried?

StuRat's horrifying example reference seems to show at least one example where two pieces of flesh that should not be directly merged can heal together. What reference makes you so sure it couldn't happen to fingers? APL (talk) 01:45, 1 April 2015 (UTC)

StuRat's example doesn't contradict my claim, in his example (of which I was already aware) the graft to the nose was still made in the side to side fashion, with the basal dermis from the arm adjoining (not facing) the basal dermis of the nose, and the epidermis of the skin from the arm next to the epidermis of the skin of the nose. It's gruesome because in order to do this they have to cut a flap away from the arm, not just touch the epidermis of the arm to the wound, as that would achieve nothing. I do actually have a bachelor's in biology, but this is junior high-school level stuff, and should be clear from the articles linked above. μηδείς (talk) 14:57, 1 April 2015 (UTC)

That was not my example. Mine was female genital mutilation. StuRat (talk) 17:26, 1 April 2015 (UTC)

Sorry, it was Sjö's example. μηδείς (talk) 18:11, 1 April 2015 (UTC)

Adhesion (medicine), for some reason, only talks about scar tissue joining internal organs together, not the skin. I'm not sure why skin is excluded there. Do they use a different term in the case of skin ? Apparently one such case is covered in skin bridge (not safe for work !) but I haven't found a general article on skin adhesions in Wikipedia. StuRat (talk) 17:43, 1 April 2015 (UTC)

March 30

What does the ground electrode actually do (in ECG)?

What does the ground electrode (on the right leg) actually do (in ECG)? what is its function as ground? 149.78.243.172 (talk) 01:08, 30 March 2015 (UTC)

Essentially, it provides a reference for quantifying the voltages picked up by the other electrodes. Here is a useful article on what the ECG voltages mean. Also see Ground (electricity) for elaboration on ground as a reference voltage. Short Brigade Harvester Boris (talk) 02:00, 30 March 2015 (UTC)

Right, the ground electrode serves the same sort of function in measuring voltage as sea level does in measuring altitude -- it provides a zero point to measure from. Looie496 (talk) 14:25, 30 March 2015 (UTC)

That's a nice analogy. I reserve the right to plagiarize it shamelessly. Short Brigade Harvester Boris (talk) 02:06, 31 March 2015 (UTC)

Well, not really. The Driven right leg circuit does not explain very well, but see the section titled "Driven right-leg circuitry" here: [1]. —eric 03:32, 31 March 2015 (UTC)

That doesn't actually contradict what we wrote, but I understand the confusion. My experience has been that students always have trouble with the concept of voltage, because there seems to be a tremendous compulsion to think of it in absolute terms, even though it is intrinsically a relative measure. It's the same difficulty that calculus students have in dealing with the constant of integration when calculating antiderivatives. Looie496 (talk) 13:41, 31 March 2015 (UTC)

Thank you Sir for your comments. So is it not possible to use the electrodes without this ground? it couldn't give us a certain indicates? (I'm surprised because I always thought the aim of the ground is only to defend on the persons from electrocution...)192.117.186.252 (talk) 02:01, 1 April 2015 (UTC)

DOE radiation worker annual exposure limit

Our spaceflight radiation carcinogenesis article contains this graph which indicates that the DOE radiation worker annual exposure limit is 20 millisievert. The source of the graph is from this JPL which discusses the radiation exposure measured by Mars Science Laboratory both during its trip to Mars and during surface operations.

I have always understood that the NRC used a 50 millisievert annual planned exposure limit for radiation workers, as described by their Standards for Protection Against Radiation, § 20.1201 Occupational dose limits for adults. Does the DOE set lower limits? I couldn't find an equivalent DOE document, but this nukeworker.com page gives a DOE annual dose limits for occupational radiation exposure of radiological workers at the National Labs of 5000 mrem which is equivalent to 50 mSv. Has there been a reduction in this limit? -- ToE 12:05, 30 March 2015 (UTC)

As another data point, Lawrence Berkeley National Laboratory publishes a radiation safety guideline that emphasizes two points: "As Low As Reasonably Achievable" exposure, and "control levels below federal dose limits." Their EH&S policy enumerates a complete table listing dosimetry limits for all types of circumstances, and all are below the ultimate limit set by federal regulation. So, it stands to reason that NASA's contractor (Southwest Research Institute) that made the graph (shown at right) found similar limits in some other unnamed Department of Energy document. I would consider them to be a reliable source. The radiation safety department at my local particle accelerator publishes Radiological Safety, and they cite 10 CFR 835 as the authoritative federal law that supersedes local policies. 10 CFR §835.202 enumerates dose limits, and appears to be the source of the 5 rem total effective dose number - but there is extensive context for that value!

Ultimately, you're mincing words and so you're bound to encounter some technicalities: what is the limit on exposure? There are many different limits (as this Department of Energy chart from the Low Dose program office illustrates), and a violation of any specific limit would entail different consequences, both with respect to health and safety, and also with respect to administrative policy enforcement.

Nimur (talk) 12:26, 30 March 2015 (UTC)

Tangentially - people looking to get a casual feel for radiation doses might enjoy this fairly well-referenced XKCD infographic, which IMO does a good job of explaining some of the orders of magnitude involved [2]. SemanticMantis (talk) 14:51, 30 March 2015 (UTC)

The Low Dose program office chart that Nimur linked to, gives the "DOE/NRC dose limit for workers" as 5 rem/year, as does DOE's Occupational Radiation Exposure Report (pages 2-1, 2-2). So it is likely that the JPL chart-maker simply made in error. Abecedare (talk) 15:14, 30 March 2015 (UTC)

Fair point, but the other resources I linked provided 2 rem as the "Administrative Control Level." "An administrative control level is a numerical dose constraint established at a level below the regulatory limits in order to administratively control and help reduce individual and collective doses." (Additional references).

You can find the very same in many other official Department of Energy reports, like the 2013 Occupational Radiation Exposure Report (which is the latest available).

Nimur (talk) 15:23, 30 March 2015 (UTC)

Yes, it is very likely that the difference arises from confusion between the DOE regulatory limit (5 rem/year) and DOE Administrative Control Level (2 rem/year), and in some sense the 2 rem/year number is more representative of what DOE monitored workers are practically kept under (Exhibit 3-4 in the DOE report). However I would still have preferred if the chart had not used the word "Limit" so casually, lest we edge up to the In through the looking glass territory. :) Abecedare (talk) 15:44, 30 March 2015 (UTC)

Thank you all. I was familiar with ALARA, but not with the Administrative Control Level. That explains it. -- ToE 17:28, 30 March 2015 (UTC)

All bureaucracy aside, it is interesting that places like Ramsar, Mazandaran seem hard to associate with cancer, despite background radioactivity over limits. When it comes to spaceflight or Mars colonization, I wonder if it is possible to get a sort of "radiation suntan" i.e. a biological response to low-level radioactivity that compensates for continuous low level exposure. Wnt (talk) 02:09, 31 March 2015 (UTC)

Bureaucracy aside! Department of Energy deals with nuclear weapons safety. Many hard lessons were learned in the first few decades - after people got sick, got hurt, and died! If you'd like to read an anecdote on this topic, Richard Feynman's short essay Los Alamos From Below talks about how bureaucracy worked during Manhattan project.

“ It was great. The lieutenant takes me to the colonel and repeats my remark. The colonel says, “Just five minutes, “and then he goes to the window and he stops and thinks. That's what they're very good at -- making decisions. I thought it was very remarkable how a problem of whether or not information as to how the bomb works should be in the Oak Ridge plant or not had to be decided and could be decided in five minutes. So I have a great deal of respect for these military guys, because I never can decide anything very important in any length of time at all. ” — Richard Feynman

With due respect, Wnt, I hope that if you ever have the privilege and responsibility to work with invisible hazardous ionizing radiation, you'll learn to respect a little bit of the bureaucracy, even if you cannot understand it.

Along the very same lines: if you should ever find yourself making decisions about safety for manned space flight, let us all hope that your spacecraft passengers can trust that your decision-making procedure has some element of rigor and a healthy, conservative margin! One may jest that NASA is bureaucratic, and one can even argue that the bureaucracy might sometimes actually impede real safety. (The very same physicist I quoted moments ago did exactly levy that accusation in his "Personal Observations" appendix to the Rogers Commission report!) But NASA must err on the side of caution, as we have all learned after many tragic spaceflight accidents. Bureaucratic rules exist because something happened, and the rule-makers wanted to make sure something never happens again. If you should ever work with high energy materials, operate a spacecraft, or generally be responsible for somebody else's well-being, "something happened" are two words you never want to hear.

Nimur (talk) 14:15, 31 March 2015 (UTC)

@Nimur: I think you read too much into my phrase. I actually have played with biological research quantities of P32, S35, occasionally tritium, and I know the basics of exposure. But it's hard to take bureaucracy too seriously when on one hand there is a whole university department tasked, mostly, with giving out these tiny amounts of radioactives (we're talking under a millicurie) in a safe way, and on the other hand, the common destination of much of them is down the sink. But I always took it much, much more seriously than the Russians, who would typically say something about Chernobyl, laugh, spray some Rad-Con to help get those pesky counts off their thumb, eat a sandwich, go back to pipetting... :) But I should say that [3] suggests that there may be real cancer consequences for the mild extra exposures of flight crews, which indeed is less than astronauts have to deal with. But we don't actually know that's the reason. Wnt (talk) 19:37, 31 March 2015 (UTC)

International Congress Series published the proceedings of a 2005 conference on the subject of Ramsar-like places with naturally high-radiation levels. My guesstimate is that we are talking about a potential single-digit percentage increase in the base-cancer rate. So it is not surprising that such an increase (even if the theoretical risk calculations are true) would not have been yet observed at Ramsar, with a population of only 30,000. Dan Fagin's Toms River gives a good journalistic account of how difficult, and frustratingly inconclusive, such epidemiological investigations can be.

NASA's Risk of Radiation Carcinogenesis has a short section towards the end on biological countermeasures against radiation during long space-flights, with links to related references.

Abecedare (talk) 02:40, 31 March 2015 (UTC)

That last reference is interesting. Mostly it goes on about antioxidants as a method, hypothetically, to reduce damage from reactive oxygen species caused by radiation. But at the end they conclude with contrary data that leaves it up in the air whether antioxidants increase or decrease the risk of cancer. Honestly I don't believe cells are test tubes and am skeptical of the relevance of a compound's redox properties. But they also mention the use of amifostine to protect tissue from radiation damage, which has been suggested to affect DNA repair; the biochemical pathways are what interest me most. For example alpha-2-macroglobulin has been proposed as a natural radioprotective agent by many means including DNA repair. [4] I'm thinking that if biology has evolved specific proteins or other substances to protect against radiation, then changes in the levels of these substances ought to affect the degree of radiation resistance. So it would subsequently require only some mechanism of sensation of damage to have a working "radiation suntan" mechanism; but so far as I know that's still only speculation on my part. Wnt (talk) 13:15, 31 March 2015 (UTC)

What is the cause, the IVF or Osborn waves?

I've read many articles and all of them (including Wikipedia on Osborn wave) says that Osborn waves caused by idiopathic ventricular fibrillation, but one of the articles (I think it's the origin of the all sources...) says the opposite. I'm confused. 213.57.29.113 (talk) 20:29, 30 March 2015 (UTC)

The Wikipedia article doesn't say they are caused by idiopathic ventricular fibrillation. It says they occur in people with ventricular fibrillation. Correlation is not causation. --Jayron32 21:30, 30 March 2015 (UTC)

What does it mean? How can you see the Osborn waves while having VF (or even idiopathic)? In all of the articles it's written that idiopathic VF (and only IF, as I understand). so What is the meaning of "occur in people with ventricular fibrillation"?. Thanks! 213.57.29.113 (talk) 21:55, 30 March 2015 (UTC)

Viral movement

How do viruses move when they're inside the body? — Preceding unsigned comment added by Joey13952 alternate account (talk • contribs) 20:51, 30 March 2015 (UTC)

They are carried by the fluids of the body, the same way other extracellular molecules are. See Virus, especially the life cycle sections. --Jayron32 21:41, 30 March 2015 (UTC)

March 31

Thesis layout

Are academics likely to penalise Students for minor things such as the page numbering one page being unaligned compared to the header by a few centimetres? Will they get a ruler and check? — Preceding unsigned comment added by 176.251.144.101 (talk) 13:07, 31 March 2015 (UTC)

If the thesis is going to be published by your university, yes, they might very well check and be quite rigorous about the format rules. Academics usually don't care about things like that, but it is generally not just academics who have to sign off on a thesis. (If it's an undergraduate thesis this might not apply, but you should check in any case.) Looie496 (talk) 13:53, 31 March 2015 (UTC)

If your institution does care then normally they will provide a style file. That way you can just include it and your thesis will be correctly formatted with little work.Dja1979 (talk) 14:23, 31 March 2015 (UTC)

When I submitted by PhD thesis, it took two tries to get the content accepted. It took three months to get the formatting accepted. I actually had to rewrite paragraphs because they didn't like how they wrapped from one page to another. I had to call the author of a paper because they disagreed with the title of his paper and wanted clarification. As for the ruler check - I had a hell of a time with tables. If a table began at the top of a page, it was 1/8th of an inch lower than the pages that began with words. I had to write a special rule into Latex to detect tables starting out a page and then add a -1/8 inch top margin to them. All in all, your advisors will likely care very little for formatting. The university itself may care a lot. 209.149.113.207 (talk) 14:29, 31 March 2015 (UTC)

Justification of Math of AC Circuit Analysis

If two variables are uncorrelated or orthogonal can they be treated as an ordered pair say complex number like AC voltage phasor or impedance phasor is there any mathematical theoremm to justify this claim — Preceding unsigned comment added by 103.24.110.221 (talk) 15:09, 31 March 2015 (UTC)

Well ... if the two variables are normalized so they have zero mean and equal standard deviation then the standard deviation of the pair is the square root of the sum of squares like a complex number norm. But overall I don't see the point. For AC analysis hte complex numbers are meaningful and useful rather than just being numbers cobbled together as a pair. Dmcq (talk) 16:34, 31 March 2015 (UTC)

Not sure what Dmcq is talking about and how it relates to your question. But short answer: Yes. Take the complex number a+ib. a and b are orthogonal and do not influence each other and therfore can be treated seperately. --109.146.20.31 (talk) 17:18, 2 April 2015 (UTC)

Exercise intensity

Since low-intensity, long-duration exercises can make the body consume more fat, I am wondering how this may be applicable on a bike ride. As a cyclist, I have encountered varying slopes along the bike path. Sometimes, the bike path may be approximately horizontal, and the ride would be a breeze. Sometimes, the bike path may descend more steeply, making the cyclist less likely to input more force on the pedals and more likely to input more force on the brakes. Sometimes, the bike path may ascend more steeply, making the cyclist go against gravity. Some people say that " Exercise is a subset of physical activity that is planned, structured, and repetitive and has as a final or an intermediate objective the improvement or maintenance of physical fitness." If the bike path is incredibly unpredictable, and the cyclist has a preference to change bike paths because it feels more exciting and pleasurable to see new sights, is that considered "exercise" or just "physical activity"? Also, is there a way to classify the intensity of a physical activity, given the unpredictability of the road? 140.254.136.154 (talk) 16:12, 31 March 2015 (UTC)

I'd say cycling for fitness is an exercise. Yes, you can classify the intensity - just wear a heart rate monitor. Most models will not only determine current heart rate, but will also allow you to integrate over time, giving a (somewhat vaguely defined) calorie count for a given period. Or use a classification scheme for routes. --Stephan Schulz (talk) 16:20, 31 March 2015 (UTC)

How do you use a classification scheme for routes? Maybe use Google to help you determine the sea level height of the terrain and the distance to get from Point A to Point B, and then use physics and mathematics to calculate the average velocity. What about the resistance of the pedals or the ground? Sometimes, the ground can be concrete (sidewalk), grass (no sidewalk), or asphalt (car roads). 140.254.136.154 (talk) 16:41, 31 March 2015 (UTC)

But then, if you want to calculate the average velocity of the bicycle to get from Point A to Point B, assuming that you are riding at a constant velocity, then you'd have to do some field research and get on the road. And that assumes that you enjoy traveling on the same road all the time. Maybe it'd be just easier to ditch the low-intensity, long-duration advice, and just have fun! 140.254.136.154 (talk) 17:11, 31 March 2015 (UTC)

Jeeez...what an awful definition. I guess by that only those who go along to a gym and do monotonous exercises watching some mindless thing on a screen are actually doing exercise. Doing something social and fun that has a physical activity component will keep people doing it far longer than all those people who pay for joining a gym and give up from sheer boredom after a few weeks. And I don't blame them giving up - it looks to me like it would move the fat from the arms and legs to the brain. If you want to make bicycling harder pull on the brake ;-) but yes I'd advise making cycling interesting as you're more likely to keep it up. Dmcq (talk) 16:24, 31 March 2015 (UTC)

The definition comes from a 1985 scientific publication. Perhaps, definitions have changed since then. 140.254.136.154 (talk) 16:52, 31 March 2015 (UTC)

As you said, "Some people say ...", and the paper itself "proposes definitions to distinguish ["Physical activity," "exercise," and "physical fitness"]". Their definitions are not universally accepted. Your latter question regarding "classify the intensity of a physical activity" should be answerable, but the former one is simply a matter of semantics. -- ToE 12:40, 1 April 2015 (UTC)

What matters is the power to weight ratio. A reasonable fit person should be at at 3 Watt/kg or higher. To maintain this level of fitness he/she should exercise at about 80% of this ratio. But if you are fitter than that, say you are at 5 Watt/kg, then you need to exercise a lot harder to maintain your fitness. So, what is hard exercise for someone may to a fitter person be such light physical exertion that it doesn't even qualify as exercise.

What is very important is that you expend a significant amount of energy compared to your resting metabolic rate. E.g. I will typically burn 1000 Kcal per day and I eat 4000 Kcal per day, so quarter of the total is due to exercise. This is a healthy ratio and also the 1000 Kcal is in absolute terms quite a lot, it is almost half my dinner. If I were to do less running (say half an hour instead of one hour) and I would do that every other day instead of every day, then the 1000 Kcal per day would become 250 kcal per day which is totally insignificant, both compared to the total amount of food that I need to eat and also in absolute terms. The 1000 Kcal extra eaten in the form of whole grain pasta, whole grain bread, olive oil will bring in a significant amount of extra nutrients that will make you a lot fitter. Count Iblis (talk) 20:32, 31 March 2015 (UTC)

So, how do you figure out the power-to-weight ratio? The weight can probably derived from a scale, but how would you be able to determine the amount of power that you exert during a physical activity? 140.254.136.178 (talk) 20:52, 31 March 2015 (UTC)

The easiest way is to do a test on a home trainer, then you can directly read off the power. Alternatively, you can use formulas that estimate this from your weight and running speed. Take e.g. this online tool. If I enter my weight of 55 kg, the distance I ran of 15 km, the time it took of 1 hour and 10 minutes, then it says that I burned 855 calories, which is actually 855 Kcal. To convert this into the power, you first need to divide this energy by 4 because only a quarter of the burned energy is the useful work done by the muscles. Then to convert to kilo Joules, you must multiply by about 4.18, and because the previous factor of 4 has some error margin, you can assume that both these factors will approximately cancel. So, the total amount of useful work my muscles have performed will have been approximately 855 KJ. If we divide this by the time in seconds we get the power which is 855 kJ/(70*60 seconds) = approximately 200 Watt. So, I've been exercising today at a power to weight ratio of about 3.6 Watt/kg, which is a good ratio.

What if you are a cyclist? How do you derive the power formula and adapt it to cycling? 140.254.70.33 (talk) 21:24, 31 March 2015 (UTC)

See here. Count Iblis (talk) 01:08, 1 April 2015 (UTC)

The latest Boeing and the latest Airbus

How many buttons, switches, and knobs are there in the cockpits of the most-recently released airplanes from Boeing and Airbus? 20.137.2.50 (talk) 17:05, 31 March 2015 (UTC)

Many! There are many variants of both the Boeing 787 and the Airbus A380; the flight decks can be configured for each customer (e.g. each airline may work with the manufacturer to customize the flight deck). They also both use glass cockpits, so there are software buttons on the touchscreen panels. You might enjoy reading the Flight Deck promotional material from Boeing, and the A380 3D Cockpit Tour from Airbus. Nimur (talk) 17:15, 31 March 2015 (UTC)

Thanks! 20.137.2.50 (talk) 17:20, 31 March 2015 (UTC)

April 1

Can lithium batteries and oxygen be used to make an impovised explosive device to blow up a cockpit door?

I'm in a plane right now, the pilot is locked out of the cockpit, he is desperately trying to get into the cockpit to prevent a plane crash. Would it be possible to make a powerful enough explosive using materials that are allowed on board such as lithium batteries and perhaps using oxygen from the on board oxygen tanks to make a powerful enough bomb to blow the cockpit door open? Count Iblis (talk) 01:15, 1 April 2015 (UTC)

Your post is in poor taste. While the question itself may have merit, in light of recent events like the Germanwings Flight 9525 crash, the way that you have chosen to phrase your question does not meet the standards of encyclopedic tone that we expect at Wikipedia. Even on April 1. Nimur (talk) 14:35, 1 April 2015 (UTC)

Piffle. It's a reasonable thing to wonder, though the effort seems forlorn. Wnt (talk) 03:37, 2 April 2015 (UTC)

• Imagine that the paragraph begins with "Suppose". Any better? —Tamfang (talk) 04:52, 2 April 2015 (UTC)

Or grab the fire extinguisher and start bashing at the lock mechanism. --Jayron32 01:17, 1 April 2015 (UTC)

Getting that door open before the copilot can crash the plane seems to be an impossible task. I think putting a bathroom in the cockpit is a better solution, so they never have to leave the cockpit in the first place. StuRat (talk) 01:44, 1 April 2015 (UTC)

crushed soda cans+O2=thermic lance. It'd take while to put togetherGreglocock (talk) 05:26, 1 April 2015 (UTC)

As was pointed out on the evening news yesterday, a year or two ago a pilot went nuts while away from the cockpit. He was then locked out, and it's a good thing he couldn't get back in. It's a no-win situation - but one that only rarely comes up. The airline has now all but admitted negligence in regard to the recent crash. He was sending signs to everyone and they weren't listening. Kind of like when kids shoot up a school, and then the experts discover he was telegraphing his intentions ahead of time. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:39, 1 April 2015 (UTC)

The real weakness is in the locking "logic", if you want to call it that.

To enter the cockpit, you need to enter a PIN on a keypad, but there is a lock switch inside the cockpit which can even disable that and keep the door locked. If it was a 2-part switch where you have to press two buttons at the same time, and so far apart that one person can't press both, that would have been much safer. The failure case would then have been reduced to a terrorist getting the PIN (already extremely unlikely), and only one man left in the cockpit. - ¡Ouch! (^{hurt me} / _{more pain}) 07:00, 1 April 2015 (UTC)

Except when terrorists capture the captain and force him to enter the pin or be killed (or watch flight attendants be killed) and the co-pilot can't lock it. Ywo people in the cockpit makes sense. difficult lock mechanism doesn't. --DHeyward (talk) 11:00, 1 April 2015 (UTC)

I partly agree with you, but there is a question of timing and luck. From what I've read, most planes are only single doored [5] [6] [7] [8]. If someone can wait until the co-pilot or pilot leaves the cabin and capture them then, how much more difficult would it be for them to rush the co-/pilot when the door is open and stop them closing it in time? I think a number of sources question whether the current protocols are even necessary or whether the risk is so small that there are better ways to handle a scenario of someone taking over the cockpit. (Of course we also have to consider how much having another pilot would help against a suicidal pilot i.e. whether they might be likely to still manage to crash the plane with one, and whether the presence of one will discourage them from trying. Similarly for a second non pilot in the cockpit.) See also my comment below. Nil Einne (talk) 17:51, 1 April 2015 (UTC)

Either you aren't in the U.S. or haven't paid attention. Magically, a drink cart and flight attendant appear in front of the cockpit door if they need to open it during flight. And no, flying isn't by majority rule. Last year, that mechanism was used to keep a looney pilot out of the cockpit. He ran up and down the aisle screaming they were all going to die and the co-pilot locked him out. The answer is really two people in the cockpit since we've decided access is an issue and uparmored the doors. There are, of course, many ways to destroy a plane if that is the goal both from the outside and the inside. Jetliners don't recover from spins and if the co-pilot really wanted to, he could have just put it into an unrecoverable attitude and they would crash no matter what the door did and it would happen even if there were no locks. Pennsylvania crash on 9/11 wasn't because the they couldn't get the terrorists out of the cockpit, it was because the plane was in an unrecoverable attitude. The November 2001 crash in New York also reiterated that the rudder (the main piece needed to recover) will be ripped off if used during departure and cruise speeds. Even busy U.S. airports have a VFR corridor that usually has small, unknown, private planes flying about 2000 feet over the departure end of the runway and no plane waiting for takeoff could avoid it if they tried something. Or the terminal where the airliners are all parked and fueled. Safety (especially TSA's view of passengers being the problem) is an illusion to placate the masses and it's why we still have incident like Malaysia flight disappearance and Germanwings. For some reason we treat "death by plane" as much more serious than any other death as it plays on very primitive fears (check out the wrongful death payout). --DHeyward (talk) 01:51, 2 April 2015 (UTC)

I think you're mostly proving my point. It's not really clear whether preventing access is really necessary. (Would the insane pilot really have gained access before anyone subdued him?) And even if it is, it's not really clear how much a 2 person rule really achieves in most cases since the suicidal pilot could still achieve their goal (as they potentially have before when there were 2 pilots). Perhaps it will help in the lone pilot hijacker scenario, on the other hand could such a pilot take out the 2nd person and proceed anyway? Yes Federal Express Flight 705 didn't work very well, but on the other hand, he may have been more insane in an unhelpful way than a dedicate hijacker may be. Nil Einne (talk) 02:03, 2 April 2015 (UTC)

I was thinking more like JetBlue Airways Flight 191. When crazy captain left, co-pilot change the code and locked him out. They had an off-duty pilot enter when psycho pilot was restrained. But psycho pilot was not getting back in. --DHeyward (talk) 05:53, 2 April 2015 (UTC)

Why not have a voice recognition mechanism? It would recognize the pilot's voice and unlock the door. That is even better than having a fingerprint or eyeball recognition system, as that could easily be used when the pilot is dead. Also, he would have to speak calmly, which is difficult when you are in serious danger (e.g. terrorist holding a plastic knife or semi-plausible-to-count-as-food tray in your face). Or, if this is too expensive, give him a damn key! KägeTorä - (^影_虎) (もしもし！) 11:38, 1 April 2015 (UTC)

Ignoring the likelihood that such a 'calm voice system' would have a high rate of both posiive and negative failure, when it does work properly you may still not be able to get in if you realise the co-pilot is trying to crash the plane when you went to the toilet, but when is that ever likely to happen? Oh wait.... Nil Einne (talk) 13:33, 1 April 2015 (UTC)

Give the passengers an electronic voting system. If 80% agree that the door should be unlocked then then the protocol is overridden. Power would then be in the hands of the many and not the few. --Aspro (talk) 13:14, 1 April 2015 (UTC)

Or the few who are able to intimidate the many enough in to doing something which may be a little silly. Nil Einne (talk) 13:36, 1 April 2015 (UTC)

Whilst the 'many' can be seduced over time (though propaganda, threats etc.), 80% though, can't be intimidated instantly. Human.. nay-animal-instincts wake up in times of immediate danger. An industrial psychologist would probably need to ascertain the right ratio of votes. It has to be better than the present protocols. Or are you saying we should abandon democracy?--Aspro (talk) 13:59, 1 April 2015 (UTC)

Who said anything about instantly? Of course there's also the question of how you actually stop vote stacking when hostile parties are in sufficient control of the plane that them forcing the way in to the cockpit eventually is a concern (which is the only real reason for current protocols). Nil Einne (talk) 17:30, 1 April 2015 (UTC)

The OP did. Any situation that happens in a 12 minute period or less doesn't (psychologically) give time for reflection. So that is an instant situation. Richard Branson (say) could ask the manufactures of the in-flight entertainment system to add a big yellow 'do not panic button' or Press to report a serous security event. Passengers near to the door or in sight of some one trying to light a fuze to his shoe 2001 shoe bomb plot can press it. If several buttons get pressed, the software can send back a information wave to the rest of the passengers. For instance. Their in-flight video can be interrupted by live video from that part of the plane. If the agent tries to spray over the cameras he will not be able to decommission the audio. The tone and timber of other passengers voices will alert passengers throughout the rest of the aircraft that something serous is happening. Some airline bosses may say “Oh No. We don't want to introduce anything that may cause panic on board” To that I say... Well think about it -your on a plane heading for a mountain or a World Trade Center or something. In that situation, passengers are no more than sheep being lead to the slaughter unless the can quickly know what is happening. An aircraft carries a lot of people and amongst that cohort will be people that can and are willing to react if they are aware of the seriousness. And Oh Boy. There is no better motivation for action than when life depends upon one acting. Even if it is altruistically – it is hard-wired into us. This was shown time and time again during the blitz in war time Britain. --Aspro (talk) 19:06, 1 April 2015 (UTC)

You seem to be completely missing my point. The issue is whether democractisation actually achieves anything that simply relaxing existing protocols, such that it's always possible for the air crew to access the cockpit door, would also achieve. The reason the current systems allow a pilot in the cockpit to stop the door being opened is primarily to stop anyone being able to force the air crew (or a pilot on the other side) to allow them in. In most cases hijackers would have some degree of time on their side, so the democratisation really achieves nothing since if you can force the aircrew, you can force the passengers to allow you access. (In fact in many circumstances it's probably easier to force the passengers. The main disadvantage is at least with the aircrew you can try and do it steathily to avoid the possibility of a United Airlines Flight 93. Often though that won't be easy. Notably if multiple aircrew have access, you'd need to either steathily take them all out which also implies knowing who they are or getting very lucky or taking most of the aircrew out without anyone noticing in time. In fact, even the attackers do that, if the passengers can find the satellite phone quickly they can still surely gain access to the cockpit without taking much longer than under the democratisation proposal.) Or just hack the in flight entertainment system.... So it's far simpler to simpler relax the current protocols, that would give you more than enough time to enter without inventing needlessly complicated "democratisation" systems while giving similar levels of risk of unwanted parties gaining access to the cockpit. (There is also the open question over whether most pilots would really obey the protocols when the passengers and crew are under active threat unless they're really convince a 9/11 style hijacking is planned. And whether you could often either fool the pilots, or force someone on the aircrew without the pilots being aware.) P.S. Also any solution with introduces panic has to weigh the risks of extra deaths due to this panic, including in the perhaps 99% of cases where there was no benefit the passengers could bring. Nil Einne (talk) 01:45, 2 April 2015 (UTC)

• This XKCD is relevant [9] - Laptop batteries have tons of stored energy, here [10] it is claimed that the energy is comparable to that of a hand grenade. SemanticMantis (talk) 14:30, 1 April 2015 (UTC)

Which is to say, I think the answer to your actual question is "yes" but you can check the math and methodologies yourself. SemanticMantis (talk) 14:32, 1 April 2015 (UTC)

I say the answer is no. Whilst lithium from batteries can be made be made to react violently, there is a problems with this. It would take time to create a device with enough power to breach the security door – and if one did this, the force would breach the integrity of the pressure cabin. The solution is democratizing the protocol. In-flight entertainment systems makes this a feasible proposition.--Aspro (talk) 14:59, 1 April 2015 (UTC)

Except when you happen to be a budget carrier with limited in flight entertainment systems like Germanwings perhaps [11]. Nil Einne (talk) 17:30, 1 April 2015 (UTC)

Then fly your family by a different carrier or wait until a better protocol is legislated for all airlines.--Aspro (talk) 19:40, 1 April 2015 (UTC)

Seems irrelevant to my point (i.e. that your proposal wouldn't have even worked in the very case which obviously brought about this question). Nil Einne (talk) 01:45, 2 April 2015 (UTC)

I actually suspect the answer it mostly no. While people sometimes talk about lithium ion battery explosions, they actual explosion is limited. See these examples [12] [13] [14]. There's a reason the more common technical term for these is "vent with flames". They can be fairly nasty in airplanes for a number of reasons but they aren't actually great explosives.

Comparing energy to hand grenades bluntly seems a little meaningless. If the figures in [15] and Energy density are correct and my calculations are not off, 20 g of petrol or even fat has more energy than a hand grenade. While your chance of managing to destroy the door with a lithium ion battery may be slim (particularly if your time is short), I think we can all agree gathering 4 or whatever of those small tubs of butter they may have would give you even less chance.

Lithium batteries may be a little better, but lithium metal still isn't the best explosive and finding enough lithium batteries of sufficient power is likely to be difficult.

I also agree with Aspro on one point. Even if you could generate an explosive force sufficient to break down the armoured door, the chance you'll do it and not compromise the plane is probably limited. I guess if you're desperate perhaps it's worth trying but you shouldn't really expect must chance of success.

Realisticly your best bet is to either hope a 2 person rule is sufficient or accept some small risk of the cabin being breached by hostile parties. Of course your two person requirement could also mean the pilots never leave the cockpit. [16] [17] [18].

Nil Einne (talk) 17:30, 1 April 2015 (UTC)

The problem with the 2 person rule is it still leave the protocol open to conspiracy.--Aspro (talk) 19:33, 1 April 2015 (UTC)

Well there's clearly always going to be some risk. If you manage to get both pilots on side than other suggestions are likely pointless in most cases since whatever they're up to would likely be over by the time anyone realises, remembering unless you get lucky you won't just have to get inside the cockpit but contact someone who can guide you on what to do (for an eventual Talk down aircraft landing). A conspiracy involving air crew and a single pilot would require either a bad protocol (ability to control over who will be the one to go in front), or dumb luck. Of course it also depends how desperate and dedicated the conspirators are anyway. If it is a conspiracy they may be more desperate than in a lone wolf situation. If they were, they would potentially take down the non compliant pilot without alerting anyone, again until it's too late. (See comments above about Federal Express Flight 705.) Nil Einne (talk) 01:45, 2 April 2015 (UTC)

Good point on the energy density of butter. I guess we need to think of time derivatives, explosion vs. conflagration, and that kind of thing. I suspect if anyone has seriously described how to make IED out of laptop batteries, it would be in some sort of modern analog to the Anarchist's Cookbook. OP may do well to trawl the shadier sides of the internet/darknet/freenet for that kind of thing. SemanticMantis (talk) 18:32, 1 April 2015 (UTC)

Incidentally while researching lithium ion batteries and planes for unrelated reasons, I notice [19] from the TSA actually says they aren't considered an explosive risk although I'm pretty sure it's mostly referring to unintentional damage or fault. Nil Einne (talk) 01:45, 2 April 2015 (UTC)

One final point before I leave this discussion for good, the lithium ion vs fat comparison seemed a little weird to me, even if the hand grenade example does illustrate the problem with simply comparing the amount of energy. I think I realise now why. The energy for a battery from XKCD was solely the energy release during discharge of the battery until the safe point. In reality the chemical energy in the battery that will be released during a venting with flames incident is likely to be fair amount higher. Partly why even in terms of a forced fire, 5 packs of 5g of butter (I said 4 packs earlier but butter has some water so 5 is probably a better number even if 4 may still be enough given the higher density) is not likely to be anywhere as impression as a lithium ion battery. Also I didn't mean to imply a single hand grenade is likely to take down the cockpit door. Nil Einne (talk) 03:07, 2 April 2015 (UTC)

N.B. OP wasn't asking "what else might be done in this situation", OP asked "Can lithium batteries ... make an impovised explosive device?") SemanticMantis (talk) 18:32, 1 April 2015 (UTC)

Then the answer is - for this application- the answer is no!--Aspro (talk) 19:21, 1 April 2015 (UTC)

• My guess would be the main problem is that the cockpit door is indeed designed to be pretty tough, and improvised bombs are notoriously unreliable. Even something that can send out chunks of lethal shrapnel may not actually provide enough of a shock wave to reliably break a nearby lock. I think that lithium and whatever is basically a deflagration that will not have a serious impact on the locking mechanism. It would be more feasible to use something like thermite - there was just a flap of news about security paranoia regarding it on a plane. But even though you could probably find some aluminum and some iron to file away at somewhere on board (everybody pool your nail files!) you'll never make it in time, unless maybe your pilot is on a trip to the South Pole (if it's indeed the pilot and not a Boeing Uninterruptible Autopilot in charge of your Malaysian Airlines flight) - your only real chance is that luckily there's a terrorist already on board with the stuff and he whips it out so that the pilot doesn't steal his 72 virgins!) Honestly, all things considered, I think your best hope physically breaching the door is that you and fellow passengers can improvise a good heavy battering ram. But as for me, the idea that came to mind was to run up to that intercom and start talking, telling the pilot that he can't stop the message from being recorded on the black box, try to get sympathy from any future listeners and then beg them earnestly, "anyone who ever hears this", to hunt down the suicidal idiot's children/wife/family/whatever and burn them almost to death, hang them by their guts, call the medical authorities to make sure it takes months to die &c. because "pilots do this all the time, kill their passengers as part of a suicide, and that's the only thing that's ever going to stop it." While it wouldn't be very likely to work, there's at least some chance the homicidal copilot would be so freaked out knowing that this earnest appeal is out there for anyone in the world to follow through on that he'd be shocked out of his idea. Wnt (talk) 03:37, 2 April 2015 (UTC)

What is real the difference between VF and IVF?

What is the difference between ventricular fibrillation (VF) to Idiopathic ventricular fibrillation (IVF)? 192.117.186.252 (talk) 01:32, 1 April 2015 (UTC)

Have you looked at our article for Ventricular fibrillation? I'm not any expert, but it seems to me that IVF is simply a subset of VF where no discernable cause can be found. Vespine (talk) 01:37, 1 April 2015 (UTC)

Per Vespine, the word "idiopathic" or "idiopathy" is medical jargon for "we have no idea". See idiopathy. --Jayron32 01:51, 1 April 2015 (UTC)

Thank you Sir. B.t.w I know what is ventricular fibrillation but I don't understand if idiopathic VF can be for example for a moment without knowing of the person about that (I knew the etymology of the word "idiopathic" but actually it didn't real help me to understand what is IVF). It's not clear for me (even I read our article -about VF- on wiki).192.117.186.252 (talk) 02:07, 1 April 2015 (UTC)

Ventricular fibrillation is when your heart goes all whoopsie-doopsie and starts beating weirdly. Idiopathic ventricular fibrillation is the same thing. The "idiopathic" bit just means "we don't know why it happened." But otherwise the expression of the symptom (heart beating all wrong) is the same. --Jayron32 02:20, 1 April 2015 (UTC)

To be pedantic, "idiopathic" means that it doesn't fall into any of the categories of known causes. For example, it is possible to cause fibrillation by electrically shocking the heart in a certain way -- that sort of fibrillation is not idiopathic, even if nobody knows that the fibrillation was caused by a shock. Looie496 (talk) 14:26, 1 April 2015 (UTC)

True, idiopathic means "unknown" in the sense of "even under perfect diagnostics, we still don't know what could have caused this", not merely "we don't know what could have caused this because we're not good at our job" or "we missed something" or something like that. Idiopathy has a sense of unknowability rather than merely unknown because of incomplete information. --Jayron32 01:16, 2 April 2015 (UTC)

Yeah, I was going to say - "idiopathic" isn't so much "we don't know" as "we checked it out and we still don't know". - Nunh-huh 01:54, 2 April 2015 (UTC)

Many years ago, my graduate advisor said "idiopathic" meant the doctors were idiots for not knowing what caused it. Short Brigade Harvester Boris (talk) 14:20, 1 April 2015 (UTC)

Verily Short Brigade Harvester Boris Many a true word is spoken in jest. --Aspro (talk) 20:47, 1 April 2015 (UTC)

I once transcribed a discharge report that contained this brilliant passage: "it could possibly be idiopathic but [...] most likely his [symptom] has unclear etiology." —Tamfang (talk) 04:56, 2 April 2015 (UTC)

Sallie Gardner at a Gallop

In Sallie Gardner at a Gallop:

He was interested in improving the performance of his horses of both types and in the scientific questions of their gait action.

Now I have studied my horse's movements and I learned much about his weaknesses. How do I instruct my horse not to kick his hind legs too high and put more weight on his front left leg? -- Toytoy (talk) 02:31, 1 April 2015 (UTC)

Just my guess, but I would think some kind of gear could be attached to the horse during training that would feel annoying when he kicked his rear legs too high, and that this would eventually condition him not to do that. No ideas on the other part. StuRat (talk) 03:00, 1 April 2015 (UTC)

Perhaps an editor will be able to provide a general, referenced description of common horse training practices used to correct gait, but in the meantime, someone may wish to help improve Sallie Gardner at a Gallop#Development: The photographs were taken in succession at one thousandth of a second. This is presumable a reference to a shutter speed of 1/1000 s, not a 1000 fps frame rate as it sounds (unless horses really do gallop at 400 Hz). I am unable to access the references. -- ToE 14:42, 1 April 2015 (UTC)

I actually believe the listed exposure-time is a dubious piece of data. As I recall, (and as published in Stanford Magazine in 2001), Muybridge used a home-made camera shutter. There is no reliable way to verify the effective exposure duration. Nowadays we could just check the EXIF data, but in 1878, it would not be practical to determine exposure speed, even if you had a whole laboratory full of equipment! Nimur (talk) 21:33, 1 April 2015 (UTC)

I've clarified the article's sentence based on Edward Armitage's 1883 Thematic Divisions of Images, pg. 176, "The word "instantaneously" does not at all represent the rapidity with which the negatives were taken. It was calculated that the time for each operation was under 1/2000 th part of a second. The interval between the production of the negatives was one twenty-fifty of a second, which if multiplied by twelve, will give about half a second for the completion of the series." -- ToE 14:15, 2 April 2015 (UTC)

I think for this specific of a question, you'll have to ask actual horse experts, perhaps at a horse forum. Here are a few that look decent [20] [21]. SemanticMantis (talk) 14:50, 1 April 2015 (UTC)

Drosophila melanogaster

Does the community agree that the Drosophila melanogaster entry would be enriched by the following link? http://www.flyfacility.ls.manchester.ac.uk/forthepublic/ — Preceding unsigned comment added by PoppiUK62 (talk • contribs) 08:37, 1 April 2015 (UTC)

 Done. Sounds good to me! Pete AU aka --Shirt58 (talk) 09:00, 1 April 2015 (UTC)

Research reports

Does writing a detailed methodology in a technical report prove you have adopted a good scientific research approach? Or should you have a separate section which describes who you worked with, where the labs you worked on were located etc? — Preceding unsigned comment added by 90.192.121.201 (talk) 13:44, 1 April 2015 (UTC)

A detailed methodology doesn't prove that you used a good approach, but it allows the reader to decide whether you did. Regarding what level of detail you should include, the basic principle is that you should include any information that a reasonable person might think could have affected the results. Ideally you should also include any information necessary for another person to replicate your experiment. If information doesn't fall into those two categories, you probably don't need to include it. Looie496 (talk) 14:16, 1 April 2015 (UTC)

There's no one right answer, it really depends on the venue. E.g. Nature papers seldom have a level of detail on methods that would allow reproduction of the experiment. Student reports often have much more detail about things like how a flask was washed. White papers and internal reports will vary by institution. As for who you worked with, they should probably be either co-authors or in the acknowledgements. Occasionally a journal article will cite "personal communication" [22] with a given person to provide reference for a claim, but some journals no longer allow this. Where the labs are should only be mentioned if it is an important influence on the findings. If you're counting ants or birds or something, location is important. Anyway, if you tell us what type of "technical report" you are interested in, we can probably give you better answers. SemanticMantis (talk) 14:26, 1 April 2015 (UTC)

It's a difficult one as my technical report is very multidisciplinary involving multiple areas of science. All the colleagues I'm working with therefore have different ideas of report structure. — Preceding unsigned comment added by 90.192.121.201 (talk) 14:39, 1 April 2015 (UTC)

That's fine. I myself have the same problem sometimes. But can you tell us if this is for a peer-reviewed journal article, and internal report, or something else? I think that's the most important split. The actual fields are probably less important, but if you could tell us even broad field names, like "computer science, biology, and physics" that would also help. SemanticMantis (talk) 14:52, 1 April 2015 (UTC)

It's an internal materials science report. The research director has his own standard format for internal reports but very often people don't follow them because he has no idea what's going on in individual research teams and there's much disagreement over his standard format. 90.192.121.201 (talk) 15:37, 1 April 2015 (UTC)

One thing to bear in mind is whether the same reasons which allow others to ignore the research director's standard format apply to you. For example, is it possible he is unlikely to see most reports but may see yours because it's very multidisciplinary? Are they high up enough that it's easy for them to ignore the research director but not for you? Nil Einne (talk) 17:01, 1 April 2015 (UTC)

It's unclear if your supervisor will care about what people on WP think. From what I can tell, you should definitely identify the people involved in the research. If not by authorship or personally, at least name the group/lab that contributed. I can't see why location would be important for purely scientific purposes, but of course the goals here are not necessarily purely scientific (e.g. an internal report might have a goal of identifying which labs can do the work faster or at lower cost). Here's a guide to methods writing from NCBI [23] that might be helpful. If you search for things like /methods writing science/ you'll find lots of similar guides from other colleges and institutes, but again, none of that really matters if your supervisor wants it done his way. SemanticMantis (talk) 18:26, 1 April 2015 (UTC)

There's no actual requirement to write about research project management but some people suggest that it's Necessary to fulfil the requirement that the approach taken for the research is scientifically rigorous. I kind of disagree. — Preceding unsigned comment added by 82.132.246.244 (talk) 13:46, 2 April 2015 (UTC)

Are there any studies as to what happens if you extract an embryo and inject it into someones blood stream?

I was wondering if any research has been done into what would happen if someone was injected with an early stage human embryo before the primitive streak stage of development. [24]

I've been reading about transplanting cancer; where genetic similarity is needed or else the immune system just suppresses it; Dr. Cornelius Rhoads tried transplanting cancer from unrelated people and apparently the immune system just suppressed it; it seems cancer can be transplanted in close relatives however. Would this be a more effective means of giving someone cancer, would the immune system just suppress it and nothing would happen, or would it be an effective embryonic stem cell transplant; or is there a 4th option? [25] Bullets and Bracelets (talk) 18:08, 1 April 2015 (UTC)

As for cancer transmission, see Clonally_transmissible_cancer. Devil_facial_tumour_disease is an example that is of particular concern. Despite reading your links, I don't understand why you might think injecting a human embryo into a human blood stream might give somebody cancer. SemanticMantis (talk) 18:20, 1 April 2015 (UTC)

• Under normal circumstances (unless it was your own clone) the mbryo would engender an immune response and be devoured by white cells. It might also form a clot. The womb is not filled with flowing blood, so there is no immune response before it implants. Once it does implant, the placenta helps to form a barrier to prevent the blood mixing directly. See Rh blood group system for possible lethal consequences of blood mixture.

μηδείς (talk) 18:24, 1 April 2015 (UTC)

• Why on God's green earth would anyone inject an embryo into the blood stream? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:28, 1 April 2015 (UTC)

Think the OP is asking about Embryonic stem cells not complete embryos.--Aspro (talk) 20:41, 1 April 2015 (UTC)

But then why specifically link to primitive streak, which refers to a stage of the blastula? SemanticMantis (talk) 20:59, 1 April 2015 (UTC)

This sounds like the type of "medical experiment" the Nazis did. I think there's a small possibility of an ectopic pregnancy, which might kill the host, say if in the brain. StuRat (talk) 20:48, 1 April 2015 (UTC)

Think you have fallen foul of Godwin's law. The OP just did not phrase his question very well - that's all. --Aspro (talk) 20:56, 1 April 2015 (UTC)

"I think there's a small possibility of an ectopic pregnancy, which might kill the host, say if in the brain."

For the umpteenth-millionth time, Stu, can we please avoid wild speculation here? There has never been a recorded case of an ectopic pregnancy in that anatomical region -- nor anywhere near it, nor anywhere outside of a small handful of locations. It may make seem like a reasonable leap to you that it could maybe occur under these extraordinary conditions, but that is nothing but a wild guess and we are here to offer direction towards actual sources on the established understanding of the topic at hand, not amateur prognosis based on pure synthesis -- especially when such speculation can easily be mistaken by an OP or other party as reflecting actual consensus science when you use such wording as "there's a small possibility of". Please save this manner of conjecture for reddit or some other space where non-expert, non-sourced speculation is welcome; this is not such a forum. Snow ^{let's rap} 22:28, 1 April 2015 (UTC)

Obviously there has never been an example of this, because an embryo has presumably never been injected into the blood stream. There have been examples of ectopic pregnancies in various other unusual places though. StuRat (talk) 00:25, 2 April 2015 (UTC)

None of which supports in the least your assertion that there would be "small possibility" (nor any realistic possibility) of such an ectopic pregnancy in the context you suggest. Look I, and presumably others here, could provide scores of physiological reasons why such a development is highly unlikely, but the problem is that, in doing so, we would also have to engage in original research in order to do so. It might be based in a deeper understanding of the histology involved than you seem to have, but original research it would still be. And that's rather the point: discussions of this nature -- which comments such as yours above invite (and sometimes necessitate for correction) -- are clear violations of WP:NOTAFORUM. I repeat: we are not here to speculate; this is a reference desk, not a forum. If you don't know for a fact that a piece of information/speculation that you are forwarding can be sourced, please just don't offer it up. This doesn't strike me as a particularly onerous condition upon participation here, anymore than it is so for any other area of Wikipedia, and most every other regular here conforms themselves to it for the most part. Snow ^{let's rap} 01:49, 2 April 2015 (UTC)

Calm down, getting upset over trivialities isn't good for your blood pressure (oops, medical advice !). :-) StuRat (talk) 02:55, 2 April 2015 (UTC)

Clearly you have no more qualms about speculating over my state of mind than you do about any other subject in this space which you rush to provide an answer to without taking due time to consider whether you are qualified or if your answer provides any empirically valid insight. I'm perfectly calm about all of this -- this is not a personal matter and is no different than any other routine procedural discussion I might comment upon on this project, aside from the facet that I (and others) have had to raise the issue with you so many times -- so I don't appreciate that sentiment. I just want you to follow policy in your contributions here, and I don't regard such matters as "trivialities", at least not in-so-far as Wikipedia is concerned. Let me be clear, we all step over the line with regard to WP:NOTAFORUM and WP:OR here on occasion; it's just a consequence of the nature of this space, and I'm no exception. But with no other user has it been such a consistent and ongoing problem over such a long period of time. I like you, Stu, but seriously, you are going to have to internalize these standards eventually, or we're all likely to end up operating under more restrictive rules that require us to source everything we discuss here. I'd rather have some self-restraint on the part of all of our regular contributors here than new overt policies because we couldn't exercise that restraint. Snow ^{let's rap} 04:06, 2 April 2015 (UTC)

@Snow Rise: re @StuRat: I think the dubious Wikipedia policy claims belong elsewhere (if anywhere); if you want to correct his answer here, then correct it. I should note that cancer, including teratoma, is a potential consequence of embryonic stem cell therapy [26]. I wouldn't expect a ground-up embryo to produce a perfectly formed fetus (though you never know till you try), but a teratoma can have a disturbing degree of organization. I don't want to give this idea too much credibility since cancer is a rare side-effect of a therapy that still has not been tried enough to really know even its ordinary effects with any confidence, but the brain, being an immunologically privileged site, in theory would be a relatively plausible location. Wnt (talk) 11:25, 2 April 2015 (UTC)

A) How are those claims dubious? Those policies are pretty straight forward and I'm aware of no exemptions made by the community at large for this area of the project. B) I thought about taking this to the talk page (as I have the last four dozen times), but the last thing we need right now is another divisive policy/behavioural discussion brought on by a contributor who has a highly specific, but persistent, issue in their approach to the boards (sound familiar?) If I took the issue to the talk page, everyone would feel compelled to comment at length and I hoped (hope) that by addressing it here, Stu (who, to his credit, doesn't get worked up over these things, in circumstances where some other editors might feel "attacked") might take it seriously and we could avoid the kind of protracted, non-productive, argumentative navel-gazing that has come to typify discussion on our talk page over the last year or so). If you want to raise the issue there, I'll participate, but there's nothing inappropriate with raising the issue here, in the discussion in which it has occured. C) I already explained above exactly why I chose not to correct his speculation in more detail. Aside from the fact that I'm tired of doing such, in order to do so I would have to engage in synthesis of my own. Nevermind the fact that my (or anyone else's) correction may be based in a deeper understanding of the relevant physiology and more likely to be factually accurate -- it would still require unsourced speculation and thus would be just as inappropriate as his original guesswork. That's not a reasonable response to a violation of policy, it's a continuation of it.

But I've said my piece on the matter (I'd have posted this most recent message on your talk page with a link here to the discussion, but I wasn't sure it would be welcome there -- I can still do that and delete this post here if you're receptive) and I'll just hope that Stu takes the observation to heart. If you want a formal talk page discussion on this matter, I'll participate, but I think we'll once again be opening a can of worms and wasting countless editor man-hours over an issue that is mostly confined (at least in it's most extreme form) to one regular. Snow ^{let's rap} 20:26, 2 April 2015 (UTC)

• @Bullets and Bracelets: I am not aware of any study that injected a blastocyst into the bloodstream instead of the uterus as is done in IVF treatment, although I wouldn't be surprised if such experiments have been performed in animals (as an aside, unless I see strong references saying otherwise, I would estimate the chances of such a transfer resulting an ectopic pregnancy in the brain to be roughly the same as the chances of a swallowed apple seed growing into a tree in ones stomach). However, you may be interested in reading up on the phenomenon of Fetomaternal microchimerism, in which some fetal cells naturally migrate to, and integrate with, the mother's body (including in the bloodstream and the brain). Abecedare (talk) 23:32, 1 April 2015 (UTC)

• The notion that an embryo could enter the bloodstream naturally or that it could travel to the brain demonstrates a lack of understanding of physiology. Topologically, the Uterus and fallopian tubes are outside the body. They are invaginations of the outer body wall. Otherwise the sperm could not enter or fertilize the egg, and the bay would have to rupture the abdominal wall to be born. There is no tissue separating the womb from the outside.

Rather, it is like the skin of the nose and throat, well vascularized, but not an internal organ like the brain or liver. Ectopic pregnancies occur when either the eggs do not exit the fallopian tubes, or in more rare cases, when they enter the abdominal coelom. This is not a solid mass or organs with blood vessels, but essentially hollow space filled with coelomic fluid in which the organs float. At no point does an embryo ever cross the walls of blood vessels, let alone cross the blood-brain barrier.

μηδείς (talk) 02:41, 2 April 2015 (UTC)

Nobody said it would enter the bloodstream naturally. You seem to have missed a key word in the Q: "injected". This means the embryo would be extracted, placed into a syringe, then injected into the bloodstream. There's nothing natural about that process, and nothing good would come of it. StuRat (talk) 02:47, 2 April 2015 (UTC)

I took "I think there's a small possibility of an ectopic pregnancy, which might kill the host, say if in the brain" as meaning a belief that this sort of thing happens. μηδείς (talk) 17:00, 2 April 2015 (UTC)

Not that it happens naturally, no. Ectopic pregnancies happen naturally, of course, but there the embryo hasn't been injected into the bloodstream. StuRat (talk) 17:03, 2 April 2015 (UTC)

• I would anticipate that the effect of injecting an embryo would be somewhat similar to injection embryonic stem cells, since many (though not all) of the embryo's cells have a relatively similar state of cellular differentiation. (Exception: trophoblast cells. The inner cell mass is what is stem cell like.) I wouldn't jump to conclusions about rejection, since during normal pregnancies some fetal cells become established in the maternal bloodstream; in many mothers Y chromosomal DNA can be detected years afterward. There are concerns with ES cells about graft versus host disease or cancer; personally I'm not convinced the treatments have been given enough of a chance for us to really know how serious such problems are. Beyond this, biology is a strictly empirical science, and any sort of extrapolation - even from an ES cell line to an embryo - is really just guesswork. Until someone does this exact experiment, we really don't know. Wnt (talk) 03:19, 2 April 2015 (UTC)

• Since the OP asked about the possibility of cancer, a link to Molar pregnancy and Gestational choriocarcinoma is relevant. These are conditions in which fetal cells cause disease and cancer. The cells do, however, have gross chromosomal abnormalities (at least in humans), containing two sets of paternal chromosomes (duplication or two sperm fertilizing an anucleate ovum), or one set of maternal chromosomes and two sets of paternal chromosomes. They derive from the trophoblast, which is the fetal side of the interface between maternal and fetal tissue. A fetus with its supporting tissue (placenta, amniotic sac) consists of foreign tissue which under other circumstances would be promptly rejected by the immune system. The trophoblast therefore has the capacity to suppress the immune response against foreign cells. Injecting trophoblast cells in humans sounds like an exceptionally bad idea to me. The experiment of transplanting (murine) embryonic cells into other mice has been performed: "Teratomas (synonym. 'embryomas') can be produced from transplants of embryos ranging in developmental age from zygotes and two-celled eggs to preterm viable fetuses.", see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2032436/pdf/amjpathol00449-0245.pdf . The mouse strain that was used, was said to be particularly susceptible to such tumors. --NorwegianBlue ^talk 11:19, 2 April 2015 (UTC)

@NorwegianBlue: This is by far the best answer; thanks! But I should caveat for the uninitiated that the paper you cite refers to inbred mice. No human population, not even in the line of the Pharaohs, has ever been so genetically homogeneous as this, and so one would expect the risk might be smaller due to the potential for rejection. Wnt (talk) 12:50, 2 April 2015 (UTC)

April 2

Is Interpretivism Opposed to Using Mathematics in Understanding Social Reality?

Interpretivism rejects the the Positivist claim that social reality can be studied objectively the way we study physical occurrences. In addition, Positivists believe that we can use mathematics to construct a formal model or explanation of a social phenomena. If Interpretivism rejects the objective analysis of social reality, does it mean that it also rejects the use mathematics in doing research?Rja2015 (talk) 11:25, 2 April 2015 (UTC)

If you really want to get into the philosophy of scientific study, I highly recommend the works of Karl Popper and see where it leads you. The kinds of questions you are asking here really lead people to give their own opinions, and are hard to answer using cited examples and references because you're really asking for philosophical justifications for scientific practices, and those justifications aren't published alongside the protocols themselves. Instead, you should focus on seeking out the philosophers who use the language and think on the level you are thinking of; Popper's work is the sine qua non of modern Scientific philosophy. --Jayron32 11:50, 2 April 2015 (UTC)

It's also worth pointing out that Popper also strongly rejected Positivism, and now most modern scientists are Popperian, relying on falsifiability as the sine qua non of science. Interpretivism is a DAB with links to Antipositivism and Qualitative_research, so that's interesting, but the articles (especially the former) contain many refs that presumably explain more details on the perspective. It's also not clear to me if Interpretivism would reject falsifiability, but if so, then works from that perspective wouldn't be considered "science" by many scientists, though it may still be a valuable academic exercise, perhaps with some similarities to ethnography. Somehow logical positivism and postpositivism fit in there as well, but OP would indeed be best served by reading some of the original sources. SemanticMantis (talk) 13:50, 2 April 2015 (UTC)

Potassium iodide as an radionicleotide preventative

Our article Potassium_iodide#Thyroid_protection_due_to_nuclear_accidents_and_emergencies state that potassium iodide only protects against the effects of radioactive iodine, and no other radionucleotide. However, cæsium is biochemically similar to potassium, and can be absorbed into bones. Cæsium is produced in nuclear power stations, and can be released in the event of a meltdown. Can cæsium be produced by nuclear weapons, and is there sufficient potassium in potassium iodide pills to stop the cæsium being absorbed by humans? Can radioactive cæsium induce cancer of the bone-marrow, leukæmia, etc? LongHairedFop (talk) 12:48, 2 April 2015 (UTC)

The thyroid needs iodine to function, so providing it with sufficient nonradioactive iodine (disregarding the radioactivity of potassium) so that it doesn't need any more prevents it from taking up the radioactive iodine. However, no part of the body needs cesium, AFAIK, so this logic doesn't apply in that case. StuRat (talk) 13:46, 2 April 2015 (UTC)

It does if you understand what the OP is asking. Chemically, cesium and potassium are similar, so the same sorts of ways your body uses potassium it may also use cesium. I have no idea if that statement is true or false, but if we take the supposition to be true, then radioactive cesium would be a problem because the body would use it in ways that it uses potassium, including as the OP notes, in bones. I have no idea about the truth of the supposition, or how to answer the question, but it's a sound question, based on what the OP already stated. --Jayron32 14:20, 2 April 2015 (UTC)

Things are in danger of getting confused. ¹³¹I has a very short half life (days). Caesium has a half life of some 30 years. Potassium iodide is fine as an 'emergency' dose, as it is the lesser of the two evils (it requires a pretty high dose to be effective) . Long term, apple juice is probably better for Caesium. It has both potassium (which reduces the bodies uptake of Caesium -which will be present in food stuffs from contaminated land) and ascorbic acid which acts as a mild chelation agent.--Aspro (talk) 14:26, 2 April 2015 (UTC)

I didn't think to check the half-lives; you are right it's the isotopes with half-lives around 1 day to 1 month are the most problematical - they are long-enough lived to be absorbed, but short enough to have a high radiation intensity. Looking at Isotopes of caesium, 129, 131, 132, 136 have half lives around this period (1⅓, 9⅔, 6½, and 13⅙ days respectively). 129 and 132 both undergo beta-decay, 131 uses electron capture, 136 undergoes beta-negative decay. I don't know how frequently 129 and 132 are produced in fission. LongHairedFop (talk) 15:49, 2 April 2015 (UTC)

Ah! So glad I did not forward cranberry juice as a prophylactic (although even that would serve admirably too): “For practical reasons the curative-like use of apple-pectin food additives might be especially helpful for effective decorporation of Cs-137.” Page 303 http://www.google.co.uk/url?q=http://cis.uchicago.edu/outreach/summerinstitute/2013/documents/sti2013_kojima_radiationprotectionafterthechernobylcatastrophe.pdf&sa=U&ei=HVUdVaLlKsbgaNaxgOAG&ved=0CBQQFjAA&usg=AFQjCNHPlov4rBHa9xXP8lghkF38K-F_Ig --Aspro (talk) 14:48, 2 April 2015 (UTC)

Erm, folks, there's some bad confusion here. Potassium iodide is used to provide iodide to compete with radioactive iodine in the thyroid. The formation of thyroid hormone is very specific, and chlorine will not do. The potassium is just a carrier to get the iodine into your system as a chemical salt, because eating elemental iodine would be an unpleasant affair (just touching it leaves long-lasting brown marks where it reacts with your skin). You could use sodium iodide according to that article - but some heart patients etc. are on low sodium diet and sodium iodide is more hygroscopic, making it less convenient to store in your bomb shelter. (This is much like the preference of pyros for potassium perchlorate rather than the sodium salt) In any case, potassium iodide offers little real protection from radioactive cesium because potassium is a different ion, a very common ion in the body, and being taken in conjunction with iodide that pretty strictly limits how much of it you can eat. It would be vastly, vastly cheaper to pursue the same agenda via salt substitute, but I'm not sure that works either. Wnt (talk) 17:24, 2 April 2015 (UTC)

Arby's trans-fats

Arby's "food" is apparently laced with trans fats: [27]. However, their ingredients list does not list any partially hydrogenated vegetable oils: [28] (you have to scroll down past the "summary" ingredients to get to the "detailed" list). So, could all these trans fats be naturally occurring, or are they just not listing the PHVO ? StuRat (talk) 13:38, 2 April 2015 (UTC)

Almost all items have 1g or less of trans fat per serving, mostly a small percentage of the total fat. Milk products and beef both naturally contain trans fats, and for a meat-centric menu like that of Arby's, that's probably the source of the trans fat (except for the breakfast biscuit which lists hydrogenated oils as an ingredient). -- Ed (Edgar181) 13:52, 2 April 2015 (UTC)

As I understand it, only partially hydrogenated vegetable oils contain trans fats. Completing the hydrogenation process eliminates them. However, as they say "hydrogenated" versus "fully hydrogenated", that leaves open the possibility that they aren't fully hydrogenated after all. This gets to the heart of my Q, could there be disguised PHVOs in that ingredients list ? StuRat (talk) 14:17, 2 April 2015 (UTC)

Then your understanding is incorrect. PHVO is not the only source of trans fats. SemanticMantis (talk) 15:27, 2 April 2015 (UTC)

That's not what I said. I said that completing the hydrogenation process eliminates the trans fats produced by partial hydrogenation. I realize there are other (natural) sources, although I thought they were on the order of tenths of a gram per serving, not grams. StuRat (talk) 15:36, 2 April 2015 (UTC)

Sorry, I guess I misunderstood "only partially hydrogenated vegetable oils contain trans fats". SemanticMantis (talk) 17:57, 2 April 2015 (UTC)

I don't think the term "hydrogenated" necessarily implies fully hydrogenated (in which case there can be no trans fat) and sometimes it can mean partial hydrogenation (which typically results in some trans fat). -- Ed (Edgar181) 19:35, 2 April 2015 (UTC)

Yep, it's not "laced" it's there naturally, see Trans_fat#Presence_in_food. See also here [29], and other sources [30] which claim that not all trans fats are equal, and that certain naturally occurring trans fats may be beneficial in certain contexts. When you search google for /trans fat beef/ [31], they scrape some USDA data and say 1 3 oz serving of 85% lean ground beef has 0.9g trans fats. SemanticMantis (talk) 13:59, 2 April 2015 (UTC)

I agree that the artificial chemical grouping of trans fats doesn't take into account that those present naturally in meat are, in all likelihood, better handled due to millions of years of natural selection than those that were first created over a platinum catalyst at elevated temperatures as a cheap lard substitute.

Additionally, there may well be some misleading (perhaps it would be safer to say "confusing") text here. It was reported that Arby's got rid of the trans fats in their cooking oils and from the process used by their upstream suppliers for preparing french fries. [32] Note that the processing of other foods before they reach the franchise is not mentioned. Our article trans fat says beef fat is 2-5% trans fats, so how is their Roast Beef max is 2 grams / 27 grams trans fat? Hmmm, I don't know. The sad thing is that they are still much, much better than many other stores that continue to push off this unsafe synthetic crap as if it were food. [33] Wnt (talk) 17:11, 2 April 2015 (UTC)

Malassezia yeast commensal frequency of occurence

What percentage of caucasian people have Malassezia genus yeast/fungus as part of their normal skin flora? --78.148.106.5 (talk) 14:25, 2 April 2015 (UTC)

The existence of Malassezia is not recorded well. It can exist, but nobody ever cared to look for it. The existence of diseases or conditions related to it are recorded. For example, I just checked an institutional medical database for studies. Out of 1,830,151 people who identify themselves as 'white', I found that 20,654 have been diagnosed with a Malassezia-related condition. 209.149.115.177 (talk) 14:39, 2 April 2015 (UTC)

Frozen coffee

I bought some iced coffee (coffee with "cream", sugar and crushed ice). I immediately put it in the freezer. The next morning it was frozen solid. I then allowed it to thaw. Once partially thawed, I had a mixture of coffee and ice again. However, the ice was not the crushed ice it had started out with, but rather a single mass of ice (clear, so containing no coffee). I don't think the ice melted then refroze. So, how did the ice transition to a single mass ? My guess is that pure water froze first, connecting the ice together, then later the remaining coffee/water mixture froze. Does that sound correct ? StuRat (talk) 14:37, 2 April 2015 (UTC)

Zone melting--Aspro (talk) 14:52, 2 April 2015 (UTC).

Also fractional freezing. When a solution freezes, the various components freeze seperately; the ice is "pure water" ice. The chunk of ice is the frozen water from the coffee as well, as the coffee freezes, the ice "Seperates" from the water, making the remaining water more concentrated coffee, and the ice pure water ice. People I knew in college used to make "freezer whiskey" in this way (marginally more palatable than pruno) by freezing beer. As the beer froze, you'd skim the ice off the top, and the remaining liquid was more concentrated alcohol. --Jayron32 15:10, 2 April 2015 (UTC)

The other interesting part is that the coffee didn't continue to separate until I got an unfrozen syrup. At some concentration, it too froze solid. StuRat (talk) 15:32, 2 April 2015 (UTC)

Did it freeze solid, or form a slush? Not to deny one possibility or the other, but many times, what you get in these situations isn't a single phase piece of ice, but small (but still pure) ice crystals with the solute particles interspersed between them, or a block of ice with lots of "holes" filled in with the heterogeneous solid particles. The appearence at a slightly closer scale may reveal that it isn't really a frozen homogenous block of coffee, but something more heterogeneous and complex. --Jayron32 15:39, 2 April 2015 (UTC)

Solid, although it did contain an air gap between the ice. Presumably there was an air bubble under the ice pack that was eventually fully enclosed in ice. StuRat (talk) 15:49, 2 April 2015 (UTC)

MosFet voltage drop

hello, in the article it says that the mosfet enters saturation when V_GS > V_th and V_DS ≥ ( V_GS – V_th ). Does this mean that Drain must be more positive than Gate by atleast V_th volts? Also, the transistor's symbol in the datasheet indicates a diode between Drain and Source with its cathode at Drain. Is it an extra diode they added to this particular transistor (to clamp inductive kickback maybe) or do all mosfets conduct when Source > Drain regardless of what Gate is, because I thought mosfets were bidirectional... Asmrulz (talk) 15:53, 2 April 2015 (UTC)

How does relative permittivity work in homogeneous mixtures?

Would that be one of those colligative properties or would simple mole/mass fraction work or...? Thieh (talk) 15:56, 2 April 2015 (UTC)

We should link to permittivity, for those attempting to answer this Q. StuRat (talk) 16:00, 2 April 2015 (UTC)

What percentage of the contiguous United States are completely undeveloped?

What percentage of the contiguous United States are completely undeveloped, as in no cities, towns, villages, suburbs, farmlands, roads, highways, etc.? I was checking Google Maps, and everywhere I looked was covered with houses, commercial buildings, public buildings, parking lots, driveways, roads, and highways. It makes me wonder about the percentage of land in the contiguous United States that is completely undeveloped and is covered by native flora and fauna. Or perhaps, all the native flora and fauna are confined to nature/wildlife parks, and indigenous peoples are confined to Indian Reservations? 140.254.136.157 (talk) 15:58, 2 April 2015 (UTC)

It's really going to depend on your precise definitions. Even in the interior of Alaska you will still find some development, just very sparsely spaced. So how sparse meets you def ? (One form of "development" even in national parks is fireroads/firebreaks. Logging roads are another.) StuRat (talk) 16:02, 2 April 2015 (UTC)

I mean land that does not have any man-made buildings, roads, or signs. 140.254.136.157 (talk) 16:22, 2 April 2015 (UTC)

Within 10 miles ? 100 ? 1000 ? And excluding signs will leave out most national parks, as they have signs on trails. StuRat (talk) 16:24, 2 April 2015 (UTC)

To put it simply it depends how large are the squares that you use to split the land. You can get a number of 0% undevelopped if you are looking for square pieces of land with no sign that are 100 miles times 100 miles. But you can get more than 50% of undeveloped land if you are looking for square pieces of land that are one yard times one yard.--147.85.172.6 (talk) 18:24, 2 April 2015 (UTC)

Yes, it's another version of the coastline paradox. StuRat (talk) 18:29, 2 April 2015 (UTC)

• More than 50% of the US population lives on the shoreline, which tells you something. See map. μηδείς (talk) 16:44, 2 April 2015 (UTC)

Some useful info at National_Wilderness_Preservation_System. SemanticMantis (talk) 17:58, 2 April 2015 (UTC)

Not quite what you asked, but this story might be of interest. The researchers looked at forest cover from satellite images and found that globally 70% of all forest land was within less than 1 km of non-forest land (usually some form of human development). The tendency for habitat fragmentation and encroachment that this implies is bad for biodiversity, etc. Dragons flight (talk) 18:17, 2 April 2015 (UTC)

By 1997, about half of the terrestrial globe was no longer "wild" due to human alterations. That number is surely higher now, but Vitousek et al. (1997) is a classic work on the subject [34], and here's a nice general review [35]. This article [36] says humans have altered about 83% of global land, accounting for 98% of arable land. Article is paywalled, see NatGeo coverage here [37].

Depending on the definition and methods of calculation, humans also appropriate about half of global net primary production [38]. In the contiguous USA, the two of the biggest biomes by area are the corn/soy Agroecosystem and turf grass. Turf grasses take up about 3X the land area of irrigated corn, the single largest irrigated crop in the USA [39]. See also [40], and refs therein. SemanticMantis (talk) 20:42, 2 April 2015 (UTC)

• Here's a map that quantifies human influence on the land in the USA [41]. The depressing conclusion: about 0.9% of the contiguous USA is "near pristine.", though 22% can still be considered "wilderness," albeit mucked up in some way. Data in the NYT map comes from here [42], which has lots of other good global maps. SemanticMantis (talk) 20:53, 2 April 2015 (UTC)

Could the ability of people savants exceed the functional capacity of the computer?

If using a special programs to teach people savants, could the ability of people savants exceed the functional capacity of the computer, for example in solving the problem - could linguistics of languages (been formed by) forming by mathematics?--83.237.221.247 (talk) 17:31, 2 April 2015 (UTC)

In pure calculations, no. So, for example, if you asked a savant to multiply a 100 digit number by another 100 digit number, maybe he could, but perhaps 1000 digits times 1000 he couldn't do, while a computer could (although it would require specific software to do so).

However, the advantage of the brain over computers is our ability to synthesize different areas of knowledge (let's say to fix a broken car). A savant may be less able to do this than an ordinary human, but still better able to do so than a computer.

So, potentially a savant could outdo a computer on something that an ordinary person could not, which requires both massive calculations and synthesis of knowledge. Protein folding comes to mind as a possibility. StuRat (talk) 18:22, 2 April 2015 (UTC)

1) Did this mean that the mathematical logic of the computer is been absolute?--85.140.138.99 (talk) 18:59, 2 April 2015 (UTC)

2) There is no protein cells called neurons?--85.140.138.99 (talk) 19:07, 2 April 2015 (UTC)

1) What does "absolute" mean?

2) There is no such thing as a "protein cell", so there is no such thing as a protein cell called a neuron. Also, this doesn't seem to be relevant to your topic... --OuroborosCobra (talk) 19:14, 2 April 2015 (UTC)

Sorry, and is there a possibility of the existence of the insulin (hypoinsulin) cells called neurons?--85.140.141.35 (talk) 19:39, 2 April 2015 (UTC)

Insulin is a hormone, not a cell. Hypoinsulin would be like diabetes, a shortage of insulin. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:32, 2 April 2015 (UTC)

Agree, that the possibility of thinking (mind) is been limited by capabilities of the biochemical cell.--85.141.237.42 (talk) 20:52, 2 April 2015 (UTC)

Which human cells are not "biochemical"? ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:55, 2 April 2015 (UTC)

Looking for an interpretation of QM

In the article on the Relational Quantum Mechanics interpretation, it seems to consider the correlation between observer and observed as considering both on equal footing.

Is there a similar interpretation in which:

• Observation by a macroscopic object is not required.

• The state according to an observer is redefined as the state according to the position and time of the observation event.

• An objective state is re-introduced as the map of the relative states onto spacetime according to this location of the observation.

Note: I'm asking about a serious (even if unpopular) physical interpretation, not something mystical like the "cone of consciousness".

166.137.12.83 (talk) 19:07, 2 April 2015 (UTC)Collin237

There is no absolute position and time of an event. What is obscure is whether that is the limit of observation or whether that is a fundamental property of the universe. Right now, it is both. Every attempt to prove that is a product of observation has failed to rule it out as a fundamental law. To wit, Spooky action at a distance and quantum entanglement. --DHeyward (talk) 20:03, 2 April 2015 (UTC)

Simultaneity puts a bit of a wrinkle on absolute times of events, no? SemanticMantis (talk) 20:25, 2 April 2015 (UTC)

Sorry, I thought "no" and didn't write it. There is no such thing as an absolute position and time. "simulataneous" is observer dependant. The hard part to understand is that observer dependance is fundamental and not "measurement error." --DHeyward (talk) 21:10, 2 April 2015 (UTC)

If the Neanderthal man had not gone extinct, then would it be put in a zoo?

If the Neanderthal man had not gone extinct, then would it be put in a zoo? Or would anatomically modern humans recognize Neanderthals as "people" and assimilate them into human populations? 140.254.136.174 (talk) 20:51, 2 April 2015 (UTC)

What makes you think Neanderthals wouldn't have put us in a zoo? ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:53, 2 April 2015 (UTC)

Besides which, many human population groups have some Neanderthal DNA - which means they alredy assimilated, a very long time ago. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:54, 2 April 2015 (UTC)

Broadly speaking, how far apart in the phylogenetic tree would humans stop recognizing closely related species as "humans"? 140.254.136.174 (talk) 20:55, 2 April 2015 (UTC)