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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)

Think the OP understood the purpose of iodine, his question was about the possible benefit of potassium component regards Caesium. Trying to treat it with salt substitute could lead people to innocently take too much and develop hyperkalemia. The link in the post I put above suggests apples (and other potassium and ascorbic rich foods) are a more 'practical' long term prophylactic.--Aspro (talk) 22:10, 2 April 2015 (UTC)

I've often encountered this notion that "natural" potassium, metered in fruit intake, is good, but "chemical" potassium, metered in grams, is bad. I'm afraid I've never understood that, because, well, it's an ion. There are lots of times when I'll give credence to claims of herbal synergy etc. but that's when there are hundreds of complex chemicals ... not this. Wnt (talk) 02:17, 3 April 2015 (UTC)

I used the word practical. I didn't say "chemical" potassium, metered in grams, is bad. A good balanced diet from uncontaminated foods should give one all the potassium one needs (which in itself is mildly radio active). Adding a medical intervention (such as low sodium salt – which in itself is mildly radio active also) is unnecessary for long term health management. Fruit juices also includes ascorbic acid (and other stuff), so their is another vitamin that does not have to be obtained from a bottle. Talk to any doctor here in the UK and they will not proscribe any supplements unless there is an obvious short term need. Lay people when offered a panacea often take too much in the belief that more will do them even more good. Thus, low sodium salt is better avoided unless prescribed for another indication.--Aspro (talk) 14:20, 3 April 2015 (UTC)

Somehow this has gotten off track. To begin with, we started out talking about doing something to prevent radioactive cesium uptake, presumably following the sort of nuclear exchange that seems to get more likely every week recently. Under such circumstances the usual medical guidance would be ... outdated. In any case I think hyperkalemia isn't that common of a problem - very few of us has any reason to think we get too little sodium, and we routinely hear recommendations to get more potassium (which we very rarely live up to by eating fruits and vegetables), so what part of sense doesn't it make to swap out some of the sodium for potassium? Within reason, of course. For many purposes a 50/50 mix just plain tastes better to me; sodium salt by itself doesn't always satisfy my desire. Wnt (talk) 17:00, 3 April 2015 (UTC)

Too little sodium is hyponatræmia.--Aspro (talk) 18:15, 3 April 2015 (UTC)

Arby's trans-fats

Arby's "food" is apparently laced with trans fats: [3]. However, their ingredients list does not list any partially hydrogenated vegetable oils: [4] (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 [5], and other sources [6] 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/ [7], 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. [8] 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. [9] 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)

Suppose the morel of this tail.. is to make your own iced coffee pro re nata.--Aspro (talk) 22:17, 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)

Assuming you're referring to an n-channel MOSFET:

1. No, the transition from linear (triode) mode to saturation mode is when the drain voltage is V_th below the gate voltage. For example, if V_th is 2 V and the gate voltage is 5 V, the transiton from linear to saturated is at a V_DS of 3 V.
2. Your second statement is correct. The diode symbol represents the drain-body p-n junction, and the source is normally connected internally to the body. If the drain-body junction is forward-biassed (V_DS greater than about -1.4 V), the FET will act as a normal p-n diode and conduct, irrespective of the gate voltage. Tevildo (talk) 09:10, 3 April 2015 (UTC)

Thank you so much! Asmrulz (talk) 12:50, 3 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)

No, it's not like colligative properties as I understand them. It's more a function of atomic spacing, phonons, and free electrons in specific orbitals - the properties that define conductivity, dielectric and ferromagnetic properties. Relative permittivity describes modification of the speed of electromagnetic wave propagation as well as the wavelength. It's more like index of refraction and chromatic aberration as it can be frequency dependent. In addition permeability is also a factor. An interesting application that may help understand it is a ferro-magnetic microwave circulator using the faraday effect in radar or optical circulator used in fiberoptics. Radar shares an antenna for both a high power transmitter and a very sensitive receiver. The receiver would be destroyed if it had to absorb the energy of the transmitter so a circulator is used to isolate them. Plasma can have these properties. So, I guess I would say that a chemical solution can have specific permittivity and permeability characteristics but it's very dependent on the chemicals in solution and the changes so permittivity would not follow the same rules as other solvents. It's very dependant on the polarity of the solvent. It's not like creating antifreeze mixtures that lowers freezing point and raises boiling point of water that only depends on concentration. --DHeyward (talk) 22:01, 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 [10], and here's a nice general review [11]. This article [12] says humans have altered about 83% of global land, accounting for 98% of arable land. Article is paywalled, see NatGeo coverage here [13].

Depending on the definition and methods of calculation, humans also appropriate about half of global net primary production [14]. 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 [15]. See also [16], 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 [17]. 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 [18], which has lots of other good global maps. SemanticMantis (talk) 20:53, 2 April 2015 (UTC)

• Human influence on the land was a factor way before the USA existed, including that corn was grown in most of the US pre-Columbus, and Native Americans purposefully set fires (while now we suppress them) and hunted the extant megafauna to extinction. The big changes since colonization were clearing of most old-growth forests (although there is far more forest cover in the east now than there was in 1900) the extinction of the Carolina parakeet and the passenger pigeon, and the elm and chestnut blights, as well as the importation of the Starling, and the horse. Looking for "pristine" is more of a religious quest than a meaningful concept outside of the Antarctic interior. μηδείς (talk) 01:24, 3 April 2015 (UTC)

And as a developing tourist destination, even Antarctica may not be free of substantial development indefinitely. But as regards the other observations, I think the OP was looking for insight into the modern state of affairs as defined specifically (if somewhat nebulously) through the concept of development, not inquiring after conceptualizations of what is meant by "pristine". That is, he seems more concerned with getting a statistical representation of what the world looks like, in a very physical sense, today, not inquiring after a general theoretical dichotomy between "natural" and "human-influenced" ecology. We can all mostly agree that those two concepts stopped being independent really anywhere on this planet a long time ago. But using his narrower definition of land upon which man-made structures are to be found, very little of the contiguous U.S. would qualify as "developed" in pre-Columbian/prehistoric North America, though clearly there was a great deal of variation amongst pre-contact native peoples with regard to both population densities and the use and nature of permanent dwellings; some had small communities based around a single large structure, others developed multiple-dwelling communities, and some isolated peoples essentially remained hunter-gatherers right up until the point of European contact. Snow ^{let's rap} 03:33, 3 April 2015 (UTC)

According to our article Wilderness, about 2.58% percent of the contiguous "lower 48" states are formally designated as wilderness. Alaska obviously has much more. I have had the privilege of spending months in the wilderness areas of California, the most populous state by far. The sense of remoteness from civilization after a few days in the wilderness is genuine. Such experiences have been deep and profound, and have enabled me to feel a sense of connection with the lives of our ancient ancestors. Cullen³²⁸ Let's discuss it 06:02, 3 April 2015 (UTC)

• I should also mention that your final question is a false dichotomy. I live in a central location in a large city in the USA. I have dozens of native plant species in my yard, about 10 different native bird species that visit, hundreds of native insect species, and even a few native mammals. Oh and at least three different native lizard species :) -- Just because a place has been developed by humans doesn't mean there aren't native flora and fauna around. SemanticMantis (talk) 13:54, 3 April 2015 (UTC)

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

Unanswerable. ←Baseball Bugs What's up, Doc? carrots→ 21:32, 2 April 2015 (UTC)
The following discussion has been closed. Please do not modify it.
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) Why are we still responding to this? This IP has absolutely no direction of inquiry, generally ignores most of our replies only to ask completely off the wall questions having nothing to do with the original topic, etc. We've done this dance, why are we still feeding this? --OuroborosCobra (talk) 21:20, 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." And it's fundamental at the QM and GR spans (though different phenomena). I personally suspect that they are very related. --DHeyward (talk) 21:10, 2 April 2015 (UTC)

See Relativity of simultaneity. Two events are only simultaneous for a finite number of observers. Other observers will see one event has happening first, another observer will see the other as occurring first. --Jayron32 01:30, 3 April 2015 (UTC)

This is not relevant to the question. It would be silly to say that there's no absolute position in the Euclidean plane because points with the same y coordinate in one coordinate system have different y coordinates in another coordinate system. Spacetime works the same way. You just have to list all of the coordinates, or identify the event in some coordinate-free way. -- BenRG (talk) 08:23, 3 April 2015 (UTC)

I don't understand what you mean by "the state according to the position and time of the observation event".

You can't map quantum states to spacetime except maybe in very special (unrealistic) cases. Even in a macroscopically almost classical world, objects like protons are still quantum. There's no way to treat them as three quarks with particular positions and spin directions and colors. -- BenRG (talk) 08:23, 3 April 2015 (UTC)

The description of the Bell inequality being false often refer to observers "Alice" and "Bob", and they can't be removed without spoiling the argument. But the Bell inequality is always false; removing the people -- or even removing everything macroscopic -- won't make it true. So the description can't require "Alice" and "Bob" to be macroscopic, and the argument would still hold even if "Alice" and "Bob" were just labels for points.

Note that regardless of how the experiment is set up, none of the particles referred to in its description is part of "Alice" or "Bob". So if "Alice" and "Bob" are points, they cannot be particle positions. So this interpretation still has each particle occupying all points. But it also has each point containing information about all particles occupying all other points.

A correlation between N particles and their fuzzy positions would be a function of N+1 positions, with the metaphor that if there were such a thing as a Planck-size "Maxwell's demon", what its maximum-information prior state knowledge would be if it's at position N+1.

I've seen Adrian Kent get close to this idea, but unfortunately he chalks it up to "consciousness" instead of actually theorizing.

166.137.14.113 (talk) 05:12, 5 April 2015 (UTC)Collin237

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)

The question calls for speculation, and is largely unknowable as a hypothetical. However, I would assume that the distinguishing characteristics are not genetics/ancestry but rather intelligence and language. To my way of thinking, regardless of ancestry, any species that could function in our world as at least approximate equals should be reasonably entitled to basic freedoms rather than enslavement and exhibition in zoos. Dragons flight (talk) 21:13, 2 April 2015 (UTC)

We've put modern humans in zoos, so I do not doubt that at some point in time we would have put Neanderthals in zoos as well. Now, whether it would still be common or contemporary practice is another question... --OuroborosCobra (talk) 21:18, 2 April 2015 (UTC)

What do you call "recognition?" Slavery exists today based on ethnicity, race and religion - not species. 160 years arguments were made over personhood vs. property in the U.S. There are variations in how animals are treated today based on how close they are to human (to wit, there are different ethical rules regarding primate research and lab rat research). We even have rules regarding animals considered pets vs. food which casues lots of international issues when the same animals are viewed differently (dogs and horses come to mind.) However, I suspect that unless mating produced offspring, the classification of "human" would be reserved for "homo sapiens." It doesn't mean that rights wouldn't expand for closely related species. --DHeyward (talk) 21:26, 2 April 2015 (UTC)

Neanderthal man reconstruction

Neanderthal man, naked.

Modern human, wearing clothes

The OP asks, "Broadly speaking, how far apart in the phylogenetic tree would humans stop recognizing closely related species as "humans"?" We have an article which addresses the question, if you accept that "human" and "person" are synonyms in this context: Great ape personhood. I have seen a lot of speculation in various media about whether a Neanderthal dressed in modern clothes would be sufficiently different from modern humans to attract attention, with opinions on both extremes. My personal opinion is that they wouldn't, and I find the images I have included rather convincing to prove this point. As Baseball Bugs says, the Neanderthals didn't really go totally extinct, as there was some interbreeding. A digression: I see that our Neanderthal article currently cites the abscence of Neanderthal mitochondrial DNA in contemporary human populations as an argument for reduced fertility in the offspring of female Neanderthals having mated with modern human males. An alternative explanation of the abscence of Neanderthal mitochondrial DNA in today's humans was suggested on this reference desk at a time when it was believed that no interbreeding had occurred, by yours truly, NorwegianBlue ^talk 00:09, 3 April 2015 (UTC)

So, if you dress a Neanderthal he would be able to mingle with computer geeks? --Noopolo (talk) 04:22, 3 April 2015 (UTC)

Well, in order to survive with modern humans, they would have needed to evolve, too. Perhaps we might have ended up with something like the ant's caste system where we would be the thinkers and planners and the Neanderthals would be the hunters, soldiers, laborers, etc. StuRat (talk) 05:43, 3 April 2015 (UTC)

If you dressed up a Jew in contemporary clothes, could you tell him apart from modern humans? If you looked at a Japanese and a Chinese, clothed or not, can you reliably tell the difference? Many societies have considered Jews subhuman, and imperial Japan considered the Chinese subhuman. Our treatment of animals is no more based on science or any objective morality than the Nazi treatment of the Jews, or the Japanese treatment of the Chinese. --Bowlhover (talk) 07:54, 3 April 2015 (UTC)

Equating genocide to our treatment of animals sounds like a crazy defense of animal rights. Starting by the fact that we can draw lines between species, and that we don't want to annihilate animals (at least not on purpose). Noopolo (talk) 11:31, 3 April 2015 (UTC)

Bowlover, that may be the most ridiculous strawman argument I've ever read. Let's just shoot it down with "I can tell when you dress an animals up." Your examples prove the difference as your two examples are human. And yes, science can tell the difference with DNA, bones, etc. Give a blood sample to a crime lab and "human or not human" is pretty straight forward and scientific. --DHeyward (talk) 12:50, 3 April 2015 (UTC)

Hmm? The fact that the two examples are clearly human was obviously Bowlhover's point. Yet despite that, these two groups have been treated horrificly by other humans in the past. This treatment had no scientific or objective moral reason. There are obvious parallels with modern treatment of animals. Why is it completely unacceptable to eat dogs, or at least raise dogs for food in some places? Is there scientific or objective moral reason why dogs should be treated so? Whereas in many countries where this is so, chicken can be kept in tiny cages for their whole lives. And certain pigs likewise. Duck and geese can be force fed with a tube. Even if you can come up with some scientific or moral reason for some of the many inconsistencies in the way we treat animals, it's questionable if you can come up with them for all of them [19]. Even the Great Ape Project could be seen in the same way. Is there a good scientific or objective moral reason to only include great apes? Nil Einne (talk) 13:40, 3 April 2015 (UTC)

My point was that the "dressing up" standard is ridiculous. Germans and Jews were hard to tell apart, yet the latter was put into gas chambers by the former. Japanese are almost indistinguishable from Chinese, but the former enslaved, raped, experimented on, and massacred the latter. The fact that a group of people can pass the "dressing up" standard is no guarantee that they should or would be treated as humans, and the fact that they don't pass doesn't mean they won't or shouldn't be. (Example: I can clearly tell a black person from a non-black person like me, but that doesn't mean black people should be enslaved. Not too long ago, of course, the majority opinion was precisely opposite.) You can tell a human from a pig? Good for you. That has precisely the same moral significance as being able to distinguish men from women, Chinese from Ethiopians, and Aztecs from Spanish. --Bowlhover (talk) 18:31, 3 April 2015 (UTC)

(Sorry, yes, this is a purely speculative side-track. Enjoy:) There's actually some deep philosophy behind the question. If Earth had multiple sentient species, what would that mean? What is sentience? We take for granted (at least nowadays!) that there is no race of people that is incapable of working mathematics, or even of appreciating music and art the way we do. "Intelligence" comes with such things, and political conniving and trickery, and noble crusades over usually loony beliefs, and all the myriad aspects of humanity, and for every population on Earth it seems to be just the same. Is that natural law? Is it inevitable that an animal either evolves to host a "soul", to put the dualism explicitly, which has all of these properties because that's how God (or somebody) made it? Or is it possible that when human ancestors met, that some simply lacked some characteristics that seem universal nowadays? Might the Neanderthals have had their own ways of communicating which were simply unintelligible to the users of modern human speech, not merely because the codings were different but because the content itself was not interpretable to modern humans (and perhaps vice versa?) I have sometimes wondered if some similar effect lingers on to this day - whether beside the pattern of sentient communication as I see it, others exist superimposed that can't be interpreted. The one case I know of, of course, is that autistic people don't read body language; but this may be relatively minor, since the most significant differences may be the most difficult to perceive. For example, sometimes I wonder if proponents of censorship have some kind of antithought that allows them to communicate, say, what kind of things mustn't be said even though they have no prior knowledge that the content exists, or is even possible. Wnt (talk) 13:14, 3 April 2015 (UTC)

April 3

Hentriacontane molecular conformation

Does hentriacontane have a bend in it as shown in the image on the article page? 78.148.106.5 (talk) 00:18, 3 April 2015 (UTC)

No, but neither does it likely have a perfectly straight conformation either. Alkanes have very low energy barriers to rotation, there is basically free rotation around the carbon single bonds; the hydrogen atoms only provide nominal steric hindrance. What this means is that, while the straight chain form is the lowest energy conformation, in reality any bulk sample of such long-chain alkane molecules will assume a bewildering array of conformations at any one moment in time. The bend in that picture is only there to fit the entire molecule in the space provided; lewis diagrams do not actually represent proper molecular geometry anyways. They're a heuristic tool for showing bonding relationships, and do a terrible job of representing real geometry in three dimensions: even more terrible considering the entire molecule is flopping around like a spaghetti noodle, along with billions and billions of its friends. --Jayron32 00:44, 3 April 2015 (UTC)

Thanks, Jayron! :) 78.148.106.5 (talk) 02:04, 3 April 2015 (UTC)

To expand a bit on what Jayron has said, the actual conformation that is lowest energy can depend on environment and is not always the straight chain. For some long chain alkanes (perhaps including hentriacontane, but I'm not sure) the lowest energy conformation is actually bent like in the image in some environments (gas phase and/or aqueous). This is because there can be van der Waals interactions gained by bending or a minimization of the surface exposed to aqueous surroundings. -- Ed (Edgar181) 11:47, 3 April 2015 (UTC)

I was curious and a few seconds on Google turned up the J. Phys. Chem. paper At What Chain Length Do Unbranched Alkanes Prefer Folded Conformations? which states, "Short unbranched alkanes are known to prefer linear conformations, whereas long unbranched alkanes are folded. It is not known with certainty at what chain length the linear conformation is no longer the global minimum". -- Ed (Edgar181) 12:15, 3 April 2015 (UTC)

To expand on the expansion by Edgar, I seem to remember from a 20-year old Organic class that chain length has a lot to do with the equilibrium between annulation and polymerization reactions. IIRC, the standard is that 5-, 6-, and 7- carbon chains are most likely to form rings during annulation reactions; that's because smaller chains have too much ring strain, while longer chains are too "floppy". "Entropically disfavored" was the term used: the chain has too many conformations which don't allow the ends to meet up. I think the same sort of thing is going on here: In any chain of any length, in pure condensed form, the chains "lowest" energy conformation would always be straight-chain staggered conformation, but in reality, given the sheer number of possible conformations for which there is little energy barrier to achieve, the "lowest" energy conformation only represents a miniscule proportion of the total molecules (even if it is the single most common conformation, there's so many others, any one conformation doesn't dominate). It's a statistical thing. --Jayron32 02:03, 4 April 2015 (UTC)

Intermediate taxa

In zoology, what's an intermediate taxon? Mentioned in the title of a source at Embryological origins of the mouth and anus, and appears in lots of Google results, but only one page appeared to give an explanation, and it's both technical (too technical for me) and botany-focused. Nyttend (talk) 13:20, 3 April 2015 (UTC)

My understanding is that it's an outdated term - a bit like missing link. The problem being that all populations are constantly changing and evolving so that describing a particular species as being "intermediate" is a trifle meaningless. Transitional fossil may be useful. Matt Deres (talk) 13:37, 3 April 2015 (UTC)

I'm pretty sure that's not what is meant in the title of the paper Nyttend is talking about here - [20], which describes how their new phylogeny shows "the disappearance of two superphyla". They are basically saying that the new genetic/cladistic/systematics methods show that two previously described unranked taxa (the superphyla) are not supported as meaningful groupings in the new analysis, even though they made sense from a morphological perspective. SemanticMantis (talk) 13:50, 3 April 2015 (UTC)

The paper cited in the first article is just talking about taxa that are not one of the eight major ranks, as well as unranked clades or groupings. Things like superphylum or subspecies or infraorder, fall into the first group of ranks that are not major, and things like Angiosperm or spermatophyta are just not ranked, as described in the infobox. See also Taxonomic_rank and Taxon#Ranks. Part of the confusion is that cladistics and systematics are slowly killing traditional morphological taxonomy, and for the past few decades people have pushed forward better classification schemes that don't fit nicely into the structure of Linnean taxonomy. Note also that botany and zoology use slightly different ranking schemes, so a phylum of animals is equivalent to a division of plants, the the term "intermediate taxon" would mean the same thing in any life science. Does that make sense? BTW that book ref is very confusing; it's not just you. The problem there is that they seem to be addressing both scientific taxonomy and folk taxonomy at the same time. SemanticMantis (talk) 13:46, 3 April 2015 (UTC)

• I can't get behind the paywall, but what they are discussing is not traditional ranks like phylum or intermediate ranks like subphylum, but clades that were found not to fit in the traditional Radiate versus Bilateria dichotomy, and the Protostome versus Deuterostome dichotomy of the eucoelomate bilaterians.

The Radiata include the Cnidaria (jellyfish and relatives) and the Ctenophora (below the Radiata lie the asymmetrical sponges and the placozoa) The Radiata have a mouth, but no anus, and no distinct front and back versus left and right. They have only two body layers, the ectoderm and the endoderm, but no internal body cavities. (Topologically the gut of a jellyfish is open to the outside of the body.

Traditionally, the advanced Bilaterians, including protostomes such as arthropods, annelids, mollusks, and others, and the deuterostomes such echinoderms, vertebrates and others have three body layers, including a mesoderm, which lines a body cavity called the coelom, and a right and left, top and bottom, front and back. The coelem in humans consists of the abdominal cavity in which the intestines and kidneys float, as well as the pericardial cavity.

The deuterstomes and protostomes were assumed to be well defined, and to vary on major themes. The deuterostomes like us formed the anus first, then the mouth during embryology, our nerve cord was dorsal to our gut, and the specifics of the way our early embryonic cells divided, and how our coeloms developed were believed to differ in a distinct way from the protostomes, like the insects, who formed their mouths before their anuses and whose main nerve cord lay below the gut, rather than above it.

But there were "intermediate taxa". Some of the (lesser known) animals with true coeloms shared both deuterstome and protostome traits. The nematodes were considered to lack true coeloms, but also shared the ecdysis form of molting with the arthropods. The flatworms were bilateria, but they lacked coeloms, and also often lacked an anus, so were considered the earliest or a degenerate offshoot, rather than highly evolved.

This image shows the traditional branching of the animal kingdom, with deuterostomes at the top right (yay for us!) protostomes on the top left, and the "lowly" flatworms and roundworms (nematodes) as a primitive sidebranch.

Recently this categorization of coelomate and acoelomate bilateria and the two great branches of protostomes and deuterostomes (which are special because were are deuterostomes) have been reshuffled, with the nematodes closer to the arthropods than the arthropods are to the annelids, with which they were once closely allied because they had segmented bodies.

The flatworms are no longer considered a low coelom-and-anus lacking sidebranch below the protostome-deuterostome split, but are now recognized as closer to the annelids and mollusks.

And the deuterostomes have lost what were once considered intermediate allies like the Brachiopods and other Lophophores to the protostomes, making the deuterostomes a small early branch out of a greater protostome group. Even the validity of the Radiata is now disputed.

It is this reshuffling of once misplaced groups like the flat worms, the lophophorata and the nematodes that is being referred to by the "end of the intermediate taxa":

μηδείς (talk) 01:55, 4 April 2015 (UTC)

Food science question -- evaporation

Resolved

I make chicken soup by adding chicken, vegetables and herbs / spices to about 10 quarts of water and boil it for about 3 hours to make soup. My mother-in-law said that she likes to do a similar thing but boil it for no longer than 2 hours -- otherwise, she says, one needs to add more water (because it boils out). I said that I like the taste of soup boiled for 3 hours or so, and that I counter the problem of water boiling out by adding water. She countered by saying that adding water dilutes the soup. I responded that the only thing evaporating is water (solvent, and not solute) so that by evaporating, the soup becomes more concentrated and all I'm doing is reconstituting it, and so not diluting it at all. And because the pot only holds 10 quarts, there is no way for me to add more water than was originally there, and so there is no danger of actually diluting it. But my mother-in-law remains resolute in maintaining that my soup is watered down and that her method is better. What is the science here -- during evaporation, is anything other than H₂O lost? DRosenbach ^{(Talk | Contribs)} 13:54, 3 April 2015 (UTC)

You will lose some VOC, e.g. some of the aromatic and flavorful compounds in the veggies and herbs. It smells good when you cook it, right? So those molecules came out of the food and into the air. All herbs and spices will change their flavor profile as they cook. If you like the way you make your soup, then you can't be doing it wrong. And you mother isn't exactly right either - she's right that the flavor will be different, but wrong that the difference is because it's "watered down." -On a side note, many recipes call for adding the same spice both early and late, or some early and some late, and this is all to refine how the profiles change as certain compounds are lost or broken down by heat. So you might appease her if you add some more herbs and spices 10 minutes before the end :) SemanticMantis (talk) 13:58, 3 April 2015 (UTC)

Actually it is watered down, for the reason you state: longer boiling removes things other than water. If you add water afterwards, you've got the same volume of water as MIL but less of the other stuff. Nonetheless I agree with SM's advice to appease your MIL... Short Brigade Harvester Boris (talk) 14:51, 3 April 2015 (UTC)

You're right, I was thinking in terms of "VOC depauperate", but for a given fixed volume, that's the same as "watered down" I guess :) SemanticMantis (talk) 15:09, 3 April 2015 (UTC)

Think this is more a case of personal preference than exact science. Two hours of simmering (not boiling) should be enough to tenderize the toughest old bird (the fowl... not the MIL). Science-wise, can I presume that as your brewing up 10 quarts at a time your buying whole chickens? If so then there is a lot of flavor in the skin. Toss all that and other parts you don't want into a pressure cooker:From the Test Kitchen: Perfect Pressure Cooker Chicken Stock Add this about 20 minutes before the soup's done. About the same time that one adds the vegetables (so they retail a little bit of al dente). The herbs could also go in at this time depending on what they are as one doesn't want to loose their aromatic flavor. Cooking With Herbs – When to Add Herbs During Food Preparation. Having said that, it won't prove anything as MIL's will always insist that her soup is better than yours!--Aspro (talk) 16:25, 3 April 2015 (UTC)

Some points:

1) When you add water, assuming it's tap water, you are also adding other things, like chlorine compounds and fluorine. Those could also affect the taste, although the chlorine compounds may boil off, too.

2) Covering the pot to avoid evaporation is one method. However, there are a few caveats with this:

2a) Make sure you have a lid that allows the water that condenses on it to pour completely back into the pot. Many seem to allow some to run down the outside of the pot. Counter-intuitively, a lid that fits snugly is more likely to leak. This is because it allows pressure to build up, then the lid is blown askew by the pressure, letting water drip out then.

2b) Similarly, the sides of the pot can't be so hot that the soup will burn on the inside as it dribbles down. This normally happens if you have a gas stove and the flame is too high, running up the sides of the pot.

2c) A covered pot is more likely to boil over, as it can't dump the excess heat as easily to the air. A much larger pot solves this problem, but it sounds like you don't have one. I have a 42 quart stockpot, for this reason.

3) I agree with adding spices at different times, as some benefit from more cooking than others. However, this also applies to other ingredients. Many veggies might get mushy if overcooked, for example.

4) Bones generally benefit from the longest cooking, as it takes time to break them down. Breaking them up would help a bit, but then you would introduce a choking hazard, unless you grind them all the way down to bone meal. You can reuse the same bones in several batches of soup, to get them the hours of cooking they need without overcooking the rest of the ingredients. StuRat (talk) 19:04, 3 April 2015 (UTC)

To that I would add:

A simmering pot does not boil over.

Yes, vegetables added too early end up mushy -like one finds in tinned food.

Bones, skin and cartilage (all the stuff that one doesn't what to end up in the soup) get quickly broken down in the pressure cooker. Then just strain. [21]. It is a no brainer when the proof of the pudding is in the tasting. This article really goes to town on method How to Make The Best Chicken Stock To that I say... No – just bung it all in! Thinks that Drosenbach should try this, then ask us all over one Friday night to perform a connoisseurs quality test. I will bring my own serviette and a large doggy bag ;-)--Aspro (talk) 20:02, 3 April 2015 (UTC)

A simmering pot can boil over, especially if the pot contains something that foams up, like milk/cream. StuRat (talk) 20:44, 3 Apri

No. temperature is set too high. It is all in the word simmering - below boiling for that particular liquid! Not the boiling point of water, liquid oxygen, liquid iron but milk and cream.--Aspro (talk) 21:28, 3 April 2015 (UTC)l 2015 (UTC)

Thanks -- I learned a lot! DRosenbach ^{(Talk | Contribs)} 19:48, 3 April 2015 (UTC)

You're welcome. I should add to 2a, that some lids have steam ports to prevent pressure from building up. Obviously you lose some water this way, but it's better than the lid sitting askew and water running down the side. As mentioned before, a pressure cooker is even better at stopping evaporation, but I don't like those, as you can't easily add things at different times and stir the pot, and there is some danger of an explosion, although hopefully not if it has a functional pressure release valve. I also like to eat some soup early (say the smaller portions of chicken that are cooked right away), and leave other parts that require more cooking to eat later. StuRat (talk) 20:09, 3 April 2015 (UTC)

Referencing

If you do a physics experiment using film and say when evaluating that the film might have been overexposed and that use of a dark room would prevent this does any of this need to be referenced? It's something a technician told me and I acknowledged the technician in the acknowledgements for his technical advice. 94.3.138.111 (talk) 15:07, 3 April 2015 (UTC)

As usual, it depends on the venue. If it's for a physics journal, it couldn't hurt to cite. Over citing is not usually seen as a problem in modern science as far as I can tell, though many journals do have citation limits. Anyway, something like this [22] is probably almost an appropriate citation for your claim, but a little searching on Google Scholar can probably get you something more appropriate. SemanticMantis (talk) 15:13, 3 April 2015 (UTC)

In general, you should go about it this way. To the readership, any statement you make must either be self-evident, or it must follow from your results, or it must be referenced. If it is self-evident for people who have had a certain education but the readership will also include other people, then a reference to a textbook is usually given. Even specialized physics articles will occasionally give references to quite elementary textbooks when the authors think that may help. Count Iblis (talk) 15:23, 3 April 2015 (UTC)

It follows from the methods which is cited. In the methods I mentioned overexposure. — Preceding unsigned comment added by 94.10.255.6 (talk) 16:32, 3 April 2015 (UTC)

Instruments need to be calibrated and cameras are instruments too. Yes, anything like this, can and should be added to a paper. It is useful because a single experiment is not worth anything until it can be independently reproduced. It helps enormously if these types of practical lab problems are included, as it forewarns other researchers what to guard against when repeating the experiment. OK, you didn't have the resources to redo and get it right – other researchers that follow will be stuck in the same position, in that they have a limited budget and your extra input may lead them to support your theory with what little money they have by not making the same errors – or oversights. Sure, I could have put that more simply but there-you-go.--Aspro (talk) 18:58, 3 April 2015 (UTC)

What is "hydrogenated vegetable oil" ?

Based on my previous Q:

I suppose this is more of a regulatory issue than a science Q, but if they don't say "partially hydrogenated vegetable oil", can it be assumed to be fully hydrogenated vegetable oil ? The lack of the word "fully" makes me nervous. One would think that 0 grams of trans fats would be a way to confirm that, but they can round anything under 0.5 g down to zero in the US, even though 0.5 g of PHVO trans fat in every "serving" would be very unhealthy for you, when they are also allowed to set absurdly small serving sizes. StuRat (talk) 20:22, 3 April 2015 (UTC)

By hydrogenating vegetable oil, manufactures can make it more viscous or by further hydrogenation make it solid like margarine. That is the simple answer. Whether it fully or partial is of no consequence. All hydrogenates are cross bonded and are thus not fit for consumption at any % (percentage). What the US needs is proper regulations where food labels 'state' the actual ingredients rather than what the manufactures would like you to believe are the ingredients.--Aspro (talk) 20:39, 3 April 2015 (UTC)

The cause of the higher melting point of hydrogenated vegetable oil is not associated with crossbonding of the carbon chains. The double bonds make it harder to form crystallin solides because they are not straight anymore. This defects in the structure increase the melting point and this makes olive oil a liquide and tallow a solide.--Stone (talk) 20:49, 3 April 2015 (UTC)

Thinks you have contradicted yourself--Aspro (talk) 21:09, 3 April 2015 (UTC)

That conflicts with my understanding and the earlier answers, that fully hydrogenating vegetable oil eliminates all trans fats. Do you dispute this, or think it would remain unhealthy for some reason other than the presence of artificial trans fat ? StuRat (talk) 20:48, 3 April 2015 (UTC)

Are you thinking that fully saturated fats are fully hydrogenated fats?--Aspro (talk) 21:01, 3 April 2015 (UTC)

For me this reads like:Crossbonding in the oil makes it unhealthy. I doubt that there is a large amount of cross bonding in that fat.--Stone (talk) 20:51, 3 April 2015 (UTC)

Which fat?--Aspro (talk) 21:05, 3 April 2015 (UTC)

Fully hydrogenated means the elimination of all double bonds. In that case, you have produced a saturated fat. Unlike the unnatural form of unsaturated fats that we call trans-fats, most saturated fats can be found in nature, so the resulting saturated fat is probably no more (and no less) unhealthy than eating comparable amounts of naturally occurring saturated fats. Eating large quantities of fat is probably a bad idea in any case, but an additional concern for trans-fats is that the human body doesn't know how to digest it efficiently (because it doesn't occur in nature). Fully hydrogenated products generally won't have that added problem, though you still have typical worries about eating too much fat. Dragons flight (talk) 21:20, 3 April 2015 (UTC)

Are you thinking that fully saturated fats are fully hydrogenated fats or fully hydrogenated fats are the same as fully saturated fats? Your input on this could be important, if your hypothesis overturns everything we know about fatty acids--Aspro (talk) 22:03, 3 April 2015 (UTC)-

As I said, fully hydrogenated fats are a kind of saturated fat. Unlike partially hydrogenated fats (i.e. trans-fats), in most cases fully hydrogenated fats are indistinguishable from naturally occurring saturated fats. You might want to go read some of the articles on the topic because you seem confused about the types of fat and the nomenclature. Dragons flight (talk) 22:20, 3 April 2015 (UTC)

“in most cases fully hydrogenated fats are indistinguishable from naturally occurring saturated fats” Oh, I would love to see your hypothesis. Trans bonds do not become cis bonds due to a bit of food manufacturing magic. Otherwise there would be no issue but there is because their not. I don't know if you have ever hear of the Internet but the explanations are all out there. --Aspro (talk) 22:47, 3 April 2015 (UTC)

Trans/cis bonding is a property of double bonds. Fully converting an unsaturated fat to a saturated fat removes all of the double bonds, both cis and trans. So yes, fully hydrogenating the fat (as opposed to partial hydrogenation) removes the trans bonds. Dragons flight (talk) 23:16, 3 April 2015 (UTC)

• if they don't say "partially hydrogenated vegetable oil", can it be assumed to be fully hydrogenated vegetable oil ? No. According to the Berkeley Welness website, "If the label just says “hydrogenated” oil, you don’t know if it’s fully or partially hydrogenated." Abecedare (talk) 22:54, 3 April 2015 (UTC)

Yes, we need better labeling of ingredients. --Aspro (talk) 23:01, 3 April 2015 (UTC)

That source also confirms Dragon flight's point above, fully hydrogenated oils are not trans fats and don't have the same problems. (It does mention possible concerns over Interesterified fats which are often being used to replace transfats. But of course something with fully hydrogenated fats doesn't have to have interesterified fats. And interesterified fats could be made without hydrogenation even if most probably use some fully hydrogenated fats.) Nil Einne (talk) 23:51, 3 April 2015 (UTC)

April 4

Hit my head, unconscious for 1 minute, half of which was spent snoring

OP has requested a diagnosis. μηδείς (talk) 17:31, 5 April 2015 (UTC)
The following discussion has been closed. Please do not modify it.
This happened a while ago. I fell asleep/passed out while leaning on a railing at like 3 am after drinking/smoking weed. I fell and hit my head. Apparently I was completely unconscious and silent for the first 30 seconds while the last 30 I was snoring. I've seen videos of people being unconscious after a head injury but none of them was snoring. So I'm wondering why I was for the last 30 seconds, and if it was because it was 3am and there was alcohol/drugs, why did it take 30 seconds of people shaking me to wake me up? Thanks, 2.102.186.225 (talk) 01:51, 4 April 2015 (UTC) Probably not relevant, but I was leaning on the railing because I was throwing up. 2.102.186.225 (talk) 01:54, 4 April 2015 (UTC) Hey, I'm not asking for medical advice (this happened ages ago). I'm just asking why I was snoring as I've never seen that before. 2.102.186.225 (talk) 13:16, 4 April 2015 (UTC) Regardless, before you read the below posts, please read Wikipedia:Medical disclaimer. IBE (talk) 06:57, 5 April 2015 (UTC) Accept OP's explanation, removing hat. See talk page discussion, [23] IBE (talk) 07:39, 5 April 2015 (UTC) Snoring is a physical consequence of a partially obstructed airway. The level of consciousness is irrelevant to the mechanism - though an obstructed airway in an unconscious patient is clearly undesirable. [24] AndyTheGrump (talk) 13:57, 4 April 2015 (UTC) Right. I have seen the same thing happen in a guy who crashed his bicycle and hit his head hard enough to be unconscious for a few minutes. Looie496 (talk) 14:32, 4 April 2015 (UTC) Why did I only start snoring in the last 30 seconds of unconsciousness then? I wasn't moved or anything. 2.102.186.225 (talk) 15:33, 4 April 2015 (UTC) Outright conjecture: for the first 30 seconds you stopped breathing. --65.95.176.148 (talk) 16:17, 4 April 2015 (UTC) The relevant (but very sparse) article is stertor. Alansplodge (talk) 17:08, 4 April 2015 (UTC) Quoting, and then immediately abrogating the disclaimer by offering diagnoses and conjecture is not acceptable. μηδείς (talk) 17:31, 5 April 2015 (UTC)

Blunt trauma and delayed death

When someone suffers an accident but survives and dies 24, 48 or 72 hours after the accident, what has deteriorated during this period that caused death? If someone has not died right away, but some days after the accident, something would be deteriorating during this period, right?. --Noopolo (talk) 15:27, 4 April 2015 (UTC)

See Major trauma. Dmcq (talk) 15:46, 4 April 2015 (UTC)

It takes some time to die even if some organs are completely nonfunctional. The kidneys, for example, remove waste from the blood, and it would take several days for the waste to build up to a fatal level (assuming no dialysis is done).

Also, if slowly bleeding internally, it may take that long to die from loss of blood. Then there could be a burst intestine, which could take that long to kill the patient due to infection. So, there's lots of ways it could happen. StuRat (talk) 17:45, 4 April 2015 (UTC)

• There are probably dozens of ways to answer this but what I can think of as the major categories would be internal bleeding, especially in the brain or body cavity, massive tissue damage leading to necrosis, and specific damage to organs like the kidneys or liver as mentioned above which don't kill you right away. Add clots leading to thrombosis to that list. My sister's uncle-in-law was hit in the head by a football on a post-thanksgiving game, felt fine, then fell into a coma two days later and died just after new years without ever waking up. See a doctor is the only advice we can give. μηδείς (talk) 22:31, 4 April 2015 (UTC)

Is sexual attractiveness distinctly physiologically and phenotypically different from physical attractiveness?

Although sexual attractiveness in non-human species seems to be more predictable and observable, which contributes to the sexual dimorphism of a species, the human species seems to be less predictable and observable. How does a human being distinguish between physical attractiveness and sexual attractiveness? Is sexual attractiveness really just physical attractiveness, plus sexual arousal? There is a well-known study in the field of psychology, in which men were placed on a suspension bridge and were held there until an attractive woman came along. The conclusion was that the fear and arousal of being on the bridge triggered the misattribution of arousal. In other words, the men were afraid about being on top of the bridge, but seeing the attractive woman made them divert their arousal and fear to the woman, thinking that the woman caused sexual arousal and hence sexually attractive. Does sexual attractiveness involve the erection of the penis in men? What about women? How do women experience sexual attraction? 66.213.29.17 (talk) 15:49, 4 April 2015 (UTC)

Think your referring to the Arthur Aron and Donald Dutton experiments. There is more than one way to explain these observations. Something that they did not mention is that Birds of a feather flock together. So if the male meets a woman in this situation, it suggest she would make a good mate who will bring up confident self-assured children -who therefore have more chance of survival. One has to be careful with psychologists, as they can design experiments to ensure the results match their own peccadilloes. So explaining why someone else, does the same experiment years later and comes up with different results. --Aspro (talk) 16:14, 4 April 2015 (UTC)

Thinking about it, this came up in conversation a while ago. Sigourney Weaver in Alien and Linda Hamiltonin in Terminator came over as a bit flumpsy in the first films but then their caricature evolved in to two females mothers that would go to the ends of the earth to protect. That is what a male wants (a subconscious drive that he's gene line will continue) and that takes two. Trophy wives are two- a-penny and can be divorced as soon as a better one comes along (and their offspring often end up as drug addicts and privileged children that strayed from the path into depravity). So meeting a female on a swinging bridge or abseiling down a cliff rather than in Mac Donald's or Starbucks makes complete sense to me.--Aspro (talk) 16:56, 4 April 2015 (UTC)

I'll suggest reading the subsequent life of Matthias Rust as a counterpoint to Aspro's approval of thrill seekers. μηδείς (talk) 23:17, 4 April 2015 (UTC)

Feeding variac with 240 VAC at 110 VAC point

So my variac has 2 input, one is for 240 VAC and the other is for 110 VAC. If I connect the 240 VAC power cable to the 110 VAC input, will it double the output voltage? Is it safe for me and the variac? 118.137.229.147 (talk) 15:54, 4 April 2015 (UTC)

Most people do not need 480 volts. When they need more than 240v they use three phase. So your variac probably comes with instructions to use it only in the way way that it was designed for. The insulation may brake down at higher voltages and quite apart from the smell you might find the results electrifying.--Aspro (talk) 17:09, 4 April 2015 (UTC)

No, it is not safe, it will probably burn it out, and it is not safe to try this out. The power drawn might be more than four times that for which it was designed (because the current might be more than doubled, as well as the voltage). Dbfirs 17:11, 4 April 2015 (UTC)

This equipment was not designed for this use. It is dangerous! If it is automatically regulated, never feed the output. It will cause a damage due unable to control this output. If it is a transformer only, never operate it out of specified voltage range. Transformers have a energy conversion efficiency, causing in reverse operation, the voltage output unregulated is higher without load, dropping under load due unregulated less than expected and dangerous due circuit brakers, fuses, thermal fuses and other savety equipment, if installed, are locaded on the other coil and will have no functionality when neccessary! The reverse operation, even in range of specified voltages is dangerous if not clear specified for such use! --Hans Haase (有问题吗) 19:11, 4 April 2015 (UTC)

There goes my plan for overvolting stuff to get more power from it. So is it safer to put a step up transformer after the variac? 118.137.229.147 (talk) 23:46, 4 April 2015 (UTC)

Yes, and remember that if you double the voltage, you can draw only half the current to avoid overloading your variac. Unless you really know what you are doing, "overvolting stuff" is more likely to produce burnout than more power for any length of time. Dbfirs 07:46, 5 April 2015 (UTC)

The Rotation of the Voyager Space Probe

www.youtube.com/watch?v=jGD4i1oNoyo at 00:30

How did she rotate the Voyager spacecraft?

It's very unlikely that she ignites the spacecraft's rocket engine which has very limited supply of propellents.

Did they use the spaceprobe's gyroscopes to control its rotation? -- Toytoy (talk) 16:10, 4 April 2015 (UTC)

Both Voyagers have hydrazine thrusters. They didn't have gyro orientation. The Jet Propulsion Laboratory use this fuel very sparingly. Which is why it has lasted so long. Brilliant work for a probe that was originally just going to Jupiter. --Aspro (talk) 17:21, 4 April 2015 (UTC)

An article from a couple of years back says one such maneuver uses 100 grams of hydrazine, with around 250 maneuvers left until the spacecraft runs out, minus whatever is needed for routine attitude control operations. The two Voyagers should run out of electrical power before they run out of hydrazine. 88.112.50.121 (talk) 18:40, 4 April 2015 (UTC)

Thank you guys. I knew that Voyagers have hydrazine thrusters. I just could not believe that they only use the thrusters to rotate the probes. I thought they probably have a gyro hidden inside so the parts don't show on the illustrations. Do they use compressed gas to propel the hydrazine in the zero-g tank?

I still don't understand why they did not use a gyroscope or just a motor and a spinning weight to rotate the Voyager. They have a nuclear power generater. An electrical rotating system may save them much fuel. -- Toytoy (talk) 15:22, 5 April 2015 (UTC)

What you describe is a reaction wheel. Some reasons Voyager's engineering team may have elected not to use them include:

• they didn't want to incur the mass cost of three of these systems
• they needed faster pointing (on close approach events) than reaction wheels could do
• they were worried the reaction wheels would fail, given the very long timeframe and very cold environment
• note the article says "over time, reaction wheels may build up stored momentum that needs to be cancelled" (by some other attitude control system)

146.200.157.224 (talk) 21:41, 5 April 2015 (UTC)

The difference between mutation of gene and genome

до свиданья ←Baseball Bugs What's up, Doc? carrots→ 22:19, 4 April 2015 (UTC)
The following discussion has been closed. Please do not modify it.
If gene and genome are always been a simple biological cells, so did it could a gene to mutate into a genome and genome to mutate into a gene?--83.237.192.63 (talk) 17:47, 4 April 2015 (UTC) Note: I’m suppose that the basis of life in the natural nature could not did it been complicated, it did been always simple, so gene and genome are always been a simple biological cells with similar as basis of viruses and bacteria.--83.237.199.127 (talk) 19:06, 4 April 2015 (UTC) I’m believe that the basis of the natural nature of the Lord God - the Spirit of Lord God it did been always simple, so the basis of life of natural nature as also it did been always simple too.--83.237.199.127 (talk) 19:35, 4 April 2015 (UTC)

April 5

What kind of psychometric test is this?

I’ve taken this exam as a requirement for a job. Unfortunately, I forgot what the exam was called. All I can remember is that the exam has 100 items grouped into five or four. Each group of five or four questions contains numerical, logical, and vocabulary questions. The questions look something like this:

Something that you use when raining --- U, S, G, C, M (Umbrella)

A small explosive thrown by hand --- G, C, W, J, Z (Grenade)

An apple costs $2.50. If you have $10, how many can you buy? --- 4, 5, 6, 4.5, 5.5

Complete the series: 1, 2, 4, 7, 11, 16, ? --- 22, 21, 20, 23, 24

What kind of psychometric test is this?49.144.142.130 (talk) 02:18, 5 April 2015 (UTC)

It reminds me of the IPATO, which was a special proprietary example of an aptitude test (more specifically - an intelligence quotient test), although the IPATO typically presented its answers in two-dimensional format just to slow certain thought-processes (and to favor people who were really good at linear algebra). Were these questions timed?

Proper administration of an intelligence test (like a Wechsler Adult Intelligence Scale test) typically costs a few hundred dollars. Fees cover the cost of the psychologists and professionals who design the test, as well as the intellectual property licenses for the questions and the scoring matrix - not to mention overhead costs to ensure sterile testing conditions. Many similar IQ tests like the Scholastic Aptitude Test and the Graduate Record Examination are administered by private-sector companies and also generally cost over a few hundred dollars. There are hundreds of alternative psychometric tests of similar caliber, vetted by individual contract companies or even built up by specialized in-house HR departments at large companies, that can be administered at much lower total cost. Perhaps your test was one such proprietary company test. Generally, such tests are not called "IQ" tests, for reasons of political correctness and avoiding liability, avoiding licensing, and avoiding strong emotional responses. Without exception, such tests are named "Incoming Applicant Aptitude Scoring System" or some similarly verbose description; this serves to obfuscate intent, but only for the subliterate.

Nimur (talk) 03:36, 5 April 2015 (UTC)

Air Pollution Maps

Are there any other detailed air pollution level maps like http://aqicn.org? I don't need real-time information like aqicn.org (though it would be nice), but I'm looking for one with the most data points. Aqicn.org only has a few per city unfortunately. WinterWall (talk) 09:18, 5 April 2015 (UTC)

No, there is no denser resource. There is satellite data but most of that is lower resolution and limited to long-term averages (plus it has large calibration issues). There is also model data, but again lower resolution. That said, why do you want more data points? Most particulate pollution (the primary health concern) has a atmospheric lifetime of days and quickly becomes mixed on a regional scale (50-100 km). Local effects, such as being next to a factory or highway tend to provide only moderate perturbations. And, of course, some of the apparent detail is related to noisy or poorly calibrated instruments. More important than where you live in the city, is where the air you were breathing came from over the last several days. Air that is imported from industrial areas will usually be dirtier than that which can from agricultural or natural areas. And that depends strongly on day-to-day (and even hour-to-hour) wind patterns. Dragons flight (talk) 20:34, 5 April 2015 (UTC)

trees

Do trees grow as far down as they grow up? if you turned it upside down would it look the same? — Preceding unsigned comment added by Kelticone (talk • contribs) 11:53, 5 April 2015 (UTC)

It depends on the species of the tree, the distribution of water and minerals in soils (roots will grown towards them), and the wind load (wind encourages deeper roots). It is said of oak trees that the roots are about the same shape as the crown, but this http://gardening.stackexchange.com/questions/1555/how-far-on-average-do-tree-roots-extend-out-from-the-base-of-the-tree indicates otherwise. LongHairedFop (talk) 12:51, 5 April 2015 (UTC)

Oaks appear to oscillate. Roots gow, then stop, leaves and so on grow, then stop and go on with roots again. --Hans Haase (有问题吗) 15:58, 5 April 2015 (UTC)

Most tree roots do not grow anywhere near as far down as the branches twigs and leaves grow up. The roots tend to spread out, often surprisingly shallowly in the case of conifers. There are a few exceptions in species that are adapted to seeking deep water tables, but generally, for most species and most soils, the root pattern is wide but not very deep. A Google search gives some patterns for different species. Dbfirs 16:23, 5 April 2015 (UTC)

Yes, if you've ever seen a toppled tree, the roots tend to cover a circular area perhaps as wide as the crown, but nowhere near as deep. μηδείς (talk) 20:54, 5 April 2015 (UTC)

When looking at the Virginia department of Forestry you see that trees roots grow to the length the widest branch tips. From this we can see that the trees roots do not grow nearly the same length as the actual tree. You also see in they looked at the depth of roots for several different types of trees. By doing this they compared several different research papers to debunk a common myth about tree roots. They found that the deeper the roots the more drought resistant a tree is. And they only grow the length of the branch tips as well. For a final source I found that Jim Urban, FASLA, a noted tree and soil expert. He found that. “Roots require three things: water, oxygen, and soil compaction levels low enough (or with void spaces sufficiently large enough) to allow root penetration. If all these conditions are met, roots can grow to great depths. Under ideal soil and moisture conditions, roots have been observed to grow to more than 20 feet (6 meters) deep. From this we see that they have to have these for the tree to grow.” (Urban) Lami229 (talk) 21:40, 5 April 2015 (UTC)LaurenAlexis

References

Female sexuality

Are lesbian women more or less likely, statistically speaking, to be virgins after the age of 30 than their straight counterparts? Please provide citations to back up your data

Eyebubummerglue (talk) 18:05, 5 April 2015 (UTC)

Not an answer to the question, but as noted at virginity, not everyone used the same definition. Many heterosexual couples consider the loss of virginity to only occur when a penis penetrates a vagina, while homosexual couples often include oral sex, mutual masturbation, and other acts as a loss of virginity. If one uses a definition that is tied to heterosexual acts, then it seems almost certain that many people who identify as homosexual are technically "virgins". On the other hand, if you include a variety of other sex acts, then many people who have been "saving themselves" and self-identify as "virgins" would probably lose that status under an expanded definition. Without a precise definition of which sex acts you mean, I doubt one could even begin to meaningfully answer the question. Dragons flight (talk) 19:37, 5 April 2015 (UTC)

Jet aerodynamics of sound

Jet aerodynamics of sound is it been save on the speed of light?--83.237.214.60 (talk) 20:26, 5 April 2015 (UTC)

I'm sorry, but this question is not understandable. Some of us can read languages other than English. Therefore you may get a more useful response if you post your question in your native language. Short Brigade Harvester Boris (talk) 20:29, 5 April 2015 (UTC)

kettles in the bath

How many 1.5L kettles of boiling water would be needed to make a 80L bath of cold water the right temperature for bathing? — Preceding unsigned comment added by 108.192.136.193 (talk) 23:28, 5 April 2015 (UTC)

Anywhere from zero to many, depending on the temperature of the "cold" water and one's personal preference as to the right temperature for bathing. Short Brigade Harvester Boris (talk) 23:47, 5 April 2015 (UTC)

Many people use a bathing temperature of roughly 40 °C, so going with that if the cold water is 20 °C, the cold and boiling water should approximately be mixed in a 3:1 ratio. For a 80 liter bath this means 60 l of cold water with 20 l of boiling water (i.e. 13.33 kettles). Of course this is just an example of a typical situation; like the comment above points out, the answer can be quite different depending on the situation. - Lindert (talk) 00:09, 6 April 2015 (UTC)

April 6

Electric bath warmer

Would warming a bath with this product actually work and would it be safe? How long might it take to warm an 80L bath to 40c? 108.192.136.193 (talk) 00:34, 6 April 2015 (UTC)

Note: The image linked shows an immersion heater. -- ToE 09:32, 6 April 2015 (UTC)

We are in no position to answer questions regarding electrical safety based on nothing but a photograph - though I very much doubt that such a device would be compatible with electrical safety regulations in most countries if used in such manner. Even ignoring the obvious risks of electrocution, anything that small capable of heating a bath full of water is going to present a significant risk of burns. In short, we can't answer your question, and even if we could, the only answer we could legitimately give is "don't even think about trying it". AndyTheGrump (talk) 03:41, 6 April 2015 (UTC)

With the caveats mentioned by AndyTheGrump above, my guess would be that, in a cold room, the bath of water would lose heat faster than that device could add it, so it would never reach 40C. In the distant past, I have heated a bath with a higher power immersion heater, and it worked, but it was a very dangerous thing to do and I now have more sense (I think). Dbfirs 07:20, 6 April 2015 (UTC)

Those are designed for heating a cup of cold water to about 80-90°C (175-195°F) for coffee/tea etc. Assuming no losses for all these calculations, we get: To heat 300 millilitres (10 US fl oz) from 10°C to 90°C requires about 100kJ of energy, to do so in 1 minute requires 1.7kW of power. To heat 50litres (about half a bathfull, before you get in( of water by 30°C (from 10°C to 40°C) requires 6,300kJ. At 1.7kW, that's just over 1 hour, so even without any losses to the air, it's impracticable. LongHairedFop (talk) 08:32, 6 April 2015 (UTC)

I doubt it's actually as high as 1.7kW. This one, for example, is just 300W.--Phil Holmes (talk) 12:06, 6 April 2015 (UTC)

regrowing fingers

How come my skin regrows when it gets cut and my bones regrow when they break, but my chopped off finger won't grow back? — Preceding unsigned comment added by 219.137.229.2 (talk) 00:56, 6 April 2015 (UTC)

Wikipedia has an article titled Regeneration in humans. I suggest you read that article, and then read any bluelinks from that article, to see where it takes you in your research. --Jayron32 01:00, 6 April 2015 (UTC)

That's a bit beyond my mental abilities. Can you just tell me? Thanks! — Preceding unsigned comment added by 219.137.229.2 (talk) 01:06, 6 April 2015 (UTC)

Healing vs. regeneration. Different processes. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:46, 6 April 2015 (UTC)

From what I found it appears that there really is not an answer to this question as of yet. There have actually been documented cases in an article from nature.com it is documented that some children have been known to regrow fingertips and some adults have even grown back parts of their liver. We have the ability when we are in the womb, humans are built piece by piece simply because we have stem cells by the time we are born our cells turn into adult somatic cells. Other animals still have stem cells even in adulthood . According to NUI-Galway’s Frank's research there may be two main reasons of human's lack of regenerative abilities. First if an amphibian loses a limb it can hide and regenerate without the need for food, this is simply not an option for a mammal with a fast metabolism that must eat, thus a mammal must regenerate "quick, and dirtily" . Professor Galway states “Because these (embryonic-like stem) cells are so versatile, it is difficult to keep them under control,” Frank explains. “They are more likely to ‘misbehave' or form tumors than differentiated cells. We hypothesize that only animals that have very simple body plans, like Hydractinia, can manage this problem because they have less complex organs and 'misbehaving' cells are less of a problem. But complex animals, like humans, need better control of their cells to maintain their highly complex organs. They have to get rid of them during early development before they become too complex.”) Lriverauk22 (talk) 03:40, 6 April 2015 (UTC)

References

Note that an injury can be completely healed if the wound is small. That is, new skin or bone can be grown. However, if the injury is larger, then you get scar tissue instead, which isn't as good (less flexible, for one thing), but seems to be necessary to plug the wound quickly, to avoid infection in the case of skin, or allow the use of the leg in the case of a broken femur, etc. In the womb there's little risk of infection and the bones don't need to be used, so there's plenty of time to grow new body parts. Not so on the outside. (The obvious solution would be to use scar tissue to quickly plug the wound, then slowly replace the scar tissue with new skin, bone, etc., but evolution doesn't seem to have figured out how to do that yet.) StuRat (talk) 06:19, 6 April 2015 (UTC)

That sort of language is very misleading - evolution doesn't "figure anything out". It is a simple process of selection where random changes that confer an advantage for survival are passed on and those that don't confer an advantage tend to die out. Richerman (talk) 09:47, 6 April 2015 (UTC)

Turning into a skeleton

After a person is buried in a coffin how long does it take for them to turn into a skeleton? 212.47.240.157 (talk) 03:18, 6 April 2015 (UTC)

After being buried 6 feet underground it takes about 10-15 years according to two of three sources I found with one source saying it could take up to 50 years but that is an extreme outlier and it highly depends on what the coffin is made out of. The 50 year process is common in those that are made out of solid oak.

Here are links to sourcing for this answer. http://www.enkicharity.com/how-long-does-it-take-for-a-body-to-decompose.html http://www.theguardian.com/lifeandstyle/2008/feb/16/healthandwellbeing.weekend2 http://www.memorialpages.co.uk/articles/decomposition.php — Preceding unsigned comment added by Trivle (talk • contribs) 03:47, 6 April 2015 (UTC) Trivle (talk) 03:53, 6 April 2015 (UTC)

"Physicist's guide to life" book?

I'm trying to recall a very good book I read a few years ago by a physicist who seemed to have a very good head on his or her shoulders and a great sense of humour. There were chapters on different themes; I think one might have been about nuclear power and another was definitely about nutrition. Some advice I remember in the nutrition chapter was something like "the best physical exercise for losing weight is pushing food away from yourself at the table". Please, what was this book? I hope somebody recognizes it. Hayttom 04:26, 6 April 2015 (UTC) — Preceding unsigned comment added by Hayttom (talk • contribs)

Did I do something wrong? My question seems to have landed in the middle of the previous answer. Hayttom 04:30, 6 April 2015 (UTC) — Preceding unsigned comment added by Hayttom (talk • contribs)

Do any of these ring a bell [25]? I believe Physics for Future Presidents includes both nuclear power and dieting, though I don't know if it matches your themes exactly. Dragons flight (talk) 05:58, 6 April 2015 (UTC)

That was quick ... yes, thanks, it was "Physics for Future Presidents: The Science Behind the Headlines". Hayttom 11:30, 6 April 2015 (UTC)

Maybe something by Richard Feynman. Richard Avery (talk) 07:07, 6 April 2015 (UTC)

Resolved

sleep deprivation

It is stated that sleep deprivation leads to madness and eventually death. However coma patients survive sometimes years in the coma but not sleeping. Can you explain? — Preceding unsigned comment added by KrikvsPicard1969 (talk • contribs) 11:34, 6 April 2015 (UTC)

Have you read Coma? ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:59, 6 April 2015 (UTC)

Are you saying that sleeping and comas are basically the same thing except that coma patients don't wake up in the morning? KrikvsPicard1969 (talk) 12:03, 6 April 2015 (UTC)