Wikipedia:Reference desk/Archives/Science/2014 December 15

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December 15

When taking a shower, does the body loses liquids (/water)?

or maybe it add liquid to our bodies? ot it's natural and it doesn't add or lose. 149.78.233.188 (talk) 01:42, 15 December 2014 (UTC)

The body neither losses nor gains any liquid. Ruslik_Zero 03:40, 15 December 2014 (UTC)

If it's a hot shower, I expect that you're going to lose some by perspiration. Alansplodge (talk) 14:02, 15 December 2014 (UTC)

The overall lose or gain is very small. Don't worry about it....Captainbeefart (talk) 14:10, 17 December 2014 (UTC)

Why is the day divided into 24 hours?

Why did they divide a day into 24 hours, why not use a multiple of 10? When was this done? 174.1.210.117 (talk) 03:30, 15 December 2014 (UTC)

Babylonians popularised the sexagesimal system, and that system is retained because of its historic prevalence. Plasmic Physics (talk) 03:36, 15 December 2014 (UTC)

The history sections of the articles Hour and 12-hour clock may be of interest, as may the article Decimal time. Deor (talk) 11:19, 15 December 2014 (UTC)

I remember hearing somewhere that if you extend your hand and hold it horizontally, the width of your hand will be approximately the distance the sun travels in one hour. So if the evening sun is 2 hands above the horizon, it is 2 hours until sundown. It turns out that on average there are 12 hands of daylight hours and 12 hands of nighttime hours and that is the origin of the 24 hour clock. I've even heard that etymologically the word "hour" derives from the word "hand". I don't know if any of this this myth or truth, but it sounds reasonable to me. Maybe someone can confirm or challenge these statements? Edgeweyes (talk) 20:31, 15 December 2014 (UTC)

It's 40 minutes at the equator. At 45 degrees latitude the Sun should take square root of 2 (1.41x) longer than 40 minutes to move this distance vertically at the horizon, at the equinox, a bit more at the solstices (especially the winter one). You would need convoluted calculus-like corrections for much of the day (the Sun has no vertical motion component at noon) and the hour was invented in Egypt (23-30N) or Mesopotamia where 1 vertical hand = 60 min is more inaccurate. I don't know if this was a historical reason. 12 is the most reasonable number of Earth's ecliptic constellations (lucky humans). I don't know how the first people did it but if I'd never heard of time units before and had to invent them I think I would count zodiac constellations and the spaces between them (24) and use 1/24 day units for the Sun, too. Anyway, doesn't hour sound like horology, Horologium, horoscopes (obsession with minute of birth), horary astrology.. horo-something is Latin for clock. Sagittarian Milky Way (talk) 03:58, 17 December 2014 (UTC)

When dividing a unit into smaller units, the only advantage of using 10s is that if you're working with base-10 numbers (as we do today) then you get a conversion factor that's easy to deal with.

For example, 16 meters = 1600 centimeters = 16000 millimeters, whereas expressing 16 days in hours is not so easy. But against that, dividing a unit into 12 or 24 parts means that it's easy to work with 1/2, 1/3, or 1/4 of the large unit. That is, 1/2 day = 12 hours, 1/3 day = 8 hours, 1/4 day = 6 hours. And there is the advantage of that system. --65.94.50.4 (talk) 04:32, 16 December 2014 (UTC)

Yes, for example if you are setting up shifts so somebody is always on duty (let's say guard duty). You can set up two 12 hour shifts, three 8 hour shifts, or four 6 hour shifts. It doesn't get messy until you try to put 5 shifts into a day. If you used a 10 hour day, even 3 shifts would be messy. StuRat (talk) 04:10, 17 December 2014 (UTC)

Marking off 90 degrees using the width of my hand at arms length takes about 9 hands. 180 degrees would be 18 of my hands. Your handage may vary. — Preceding unsigned comment added by 50.43.56.168 (talk) 01:48, 18 December 2014 (UTC)

Heating Shale Oil with Microwaves

According to news articles I've read on new shale oil extraction techniques, microwaves can be used to heat oil shale in situ producing crude oil and reducing its viscosity. Since crude oil is mostly non-polar hydrocarbons, how can microwaves be used for this type of heating? 202.155.85.18 (talk) 03:47, 15 December 2014 (UTC)

Crude oil shale might be mostly non-polar but not a purely microwave transparent non-polar matrix. There is a lot of other gunk in it, that acts as 'microwave couplers'. Since oil has about half the SHC of water -heating will be rapid! Having said that. Even with pure non-polar substances, some distortion of the dipole molecule can take place. Thus, the temperature in a pure substance will rise very, very slowly at first. However, as the dielectric constant shifts due to the temperature rise, so will the microwaves loose more energy to the non-polar substance with increased efficiency and the substance will start to heat more rapidly. So don't put a cup of oil in your microwave oven– not joking. --Aspro (talk) 04:51, 15 December 2014 (UTC)

The discussion here is quite interesting in this regard. Short Brigade Harvester Boris (talk) 05:01, 15 December 2014 (UTC)

You can't get cell phone reception in a tunnel. This indicates that microwaves don't carry through many yards of rock. I don't know precisely why, though I think of just about any rock as a matrix of positive and negative ions, hence capable of interacting with electromagnetic radiation. The oil is not all that is present in oil shale, which is why special measures are needed to begin with. I am rather amazed that the equipment is able to put in 0.65 MJ per kilo of extracted oil;[1] I'm surprised that such powerful microwave emitters have not been pressed more often to the service of evil... Anyway, from [www.scirp.org/journal/PaperDownload.aspx?paperID=18363] I think the heating wells are about 4-8 meters from the extraction wells, so the rules of the microwave oven don't well apply - those microwaves are going much further. That source also makes a very vague mention of tuning the microwaves to control what is heated which is no doubt potentially interesting. Wnt (talk) 09:14, 15 December 2014 (UTC)

Here is a complete explanation of how RF penetration is archived. In situ radio frequency selective heating system & In-situ tuned microwave oil extraction process P.S. My oven can easily achieve 0.16 MJ/kg. Whilst it may be true that a mouthful of my culinary efforts, would be all that's needed to convince any gourmet that it has already been put to evil use, it's only because I lost the instruction manual. So with me at the controls it has become a weapon of bio-Mass Destruction I suppose.--Aspro (talk) 22:21, 16 December 2014 (UTC)

Long-term effects of antihistamines on mind and CNS

Question by Ram nareshji deleted as probable copyvio [2] Nil Einne (talk) 14:46, 16 December 2014 (UTC)

This was a bit of a bee in my bonnet a few years ago. If a substance alters the response to a single receptor type or a family of receptor types over a long enough period. Then the cell will adapt. Before adaptation is complete, it will obviously have some effect and a change of affect. On discontinuation of the substance, the cell will attempt to return to its previous state. During this return, an opposite affect will be evoked. The type of synthetic antihistamines that you refer to is for short time use but a small and perceptible change in mental faculties is to be expected. --Aspro (talk) 05:25, 15 December 2014 (UTC)

B cell receptor editing

Question by Ram nareshji deleted as probable copyvio [3] Nil Einne (talk) 14:46, 16 December 2014 (UTC)

An insightful question! I'd been aware of clonal deletion to prevent central tolerance, but had not been aware of receptor editing as a means of solving it (rather than just dealing with low expression levels [4]), or that it was so common. At least this paper [5] says that cells can de-differentiate and go back and rearrange both kappa and lambda loci, but the one preceding seemed skeptical of it. This seems like an active research topic that probably requires a thorough research of at least everything recent on PubMed to get the sense of what is currently thought about it. Wnt (talk) 09:34, 15 December 2014 (UTC)

Why can't you just buy antibiotics?

See above. It seems like you can only get them via prescription, which is fine I guess, but going to the doctor is a pain. I'm not asking for medical advice, I just want to know why you can't just buy them over the counter if you have an infection or something. 81.138.15.171 (talk) 11:03, 15 December 2014 (UTC)

Typically the doctor will prescribe a certain amount for a certain number of days. There are enough problems already with Antibiotic resistance, and popping them on a whim, as with aspirin, would only make that problem worse. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:31, 15 December 2014 (UTC)

It depends where you are. A good place to start reading is our article on medical prescriptions.

In the United States, many controlled substances - particularly, medicinal and non-medicinal drugs - are "scheduled" (controlled) as required by the Controlled Substances Act. I am not certain, but I think most common antibiotics - like Amoxicillin and Cipro - are regulated by entirely separate legislation (see, for example, the FDA's website on New Drug and Antibiotic Regulations, which cites specific changes to 21 CFR made in 1985, among dozens of other laws); but the general rules are roughly parallel: possession and sale of such substances is regulated by the state or federal government, ostensibly to prevent harm. Only certain people are allowed to have or sell such substances; and only after specific paperwork is filed. The authority to grant such permission is among the many privileges granted to a licensed medical doctor - a license that is also granted by the local or federal government. If you really want to trace all of this to root-cause, from a "scientific" perspective, we could trace this to utilitarian descriptions of the evolutions of theories regarding the social contract, delegation of responsibilities, specialization of labor, and so on. Without doubt, you will find dissenting opinions from many people who believe that they ought to be able to freely and openly carry and sell any substance, weapon, antibiotic, radioactive isotope, and so forth, all without government intervention of any kind; but irrespective of their opinion, the present status-quo is that you may not do such things at present in most parts of the United States.

Nimur (talk) 16:36, 15 December 2014 (UTC)

However, specific to antibiotics, the public health concerns outweigh the individual concerns regarding chance for abuse or personal safety. Basically, though the chance for addictive abuse is nil, and the chance for adverse reactions is small (but real), the main concern is what Bugs describes above: antibiotic resistance. Overuse of antibiotics is to blame for many major health problems societally (like MRSA to name one), and the issue is related to the tragedy of the commons; if unregulated every will use antibiotics all the time, even if they don't need them, and while it may not harm them as individuals, it has the effect of causing major health problems for society in terms of antibiotic resistance. By regulating antibiotics, we're able to mitigate that effect. --Jayron32 16:45, 15 December 2014 (UTC)

The non-libertarian societal benefit arguments being made above are interesting, but some of the practical reasons why you should consult a professional are: (1) misdiagnosis, (2) specificity, (3) side effects. The first problem is misdiagnosis. If you have a cough due to a viral cold or asbestosis or lung cancer then not only will the antibiotic not help, you may fail to get proper treatment, like chemotherapy, which is often started very soon after a lung cancer diagnosis.

Second, specific antibiotics are often prescribed for different ailments. Amoxicillin is prescribed for upper-respiratory infection, but not for diverticulitis, in which case Cipro is called for. I think penicillin is still standard for syphillis, but you'd have to check with a professional.

Third, antibiotics are strong medicines, and the can have serious side effects, such as penicillin allergies, and effects on liver and kidney function, gut flora, light sensitivity, incompatibility with alcohol consumption, and so forth. There are other issues, like administration whether by injection or IV, and some very strong antibiotics require regular, even several times daily blood testing. Most of this is something we should not want to do on our own. μηδείς (talk) 19:16, 15 December 2014 (UTC)

Essentially correct. Note that reservation of most antibiotics as requiring prescription significantly pre-dates concern over superbugs in the broader public sphere. Pharmaceutical-grade antibiotics are like any medication; there's a certain degree of occurrence of adverse reaction and they can have untoward physiological effects when abused or even when used in a manner consistent with usual medical practice. A small handful even have toxicity issues if consumed too far beyond their manufacture date. Control of the manufacturing process also needs to be rigorous, as dosing and binding agents can both drastically influence the efficacy and safety of many such pharmaceuticals. All of these concerns would have made good arguments for strong control, well in advance of resistance becoming the other major class of factor driving the decisions of regulators today. None of which is to say that physicians and pharmaceutical firms haven't been aware of the concept of resistance for as long as antibiotics have existed as modern commercial products; they clearly have, but the concern has grown more and more prominent (and more and more visible to the layman) in recent years. Snow talk 11:14, 17 December 2014 (UTC)

I think it's important to realize that antibiotics are sold freely over the counter in countries including Russia[6] and the Dominican Republic,[7] and as explained in the second article this translates to availability within some subcultures even in the U.S. I don't see much study of the difference between Russia and the U.S. on resistance (I don't get much from this) but the sky doesn't seem to have fallen on them. Honestly, I think that medical ethics is purely the political pursuit of profit, and this is an example - merely a racket to keep-away the medicine from the sick until they pay. I don't see much consideration of the mortality and spread of disease caused when some poor luckless sap catches a strep throat on a Thursday night. (It seems hard to find a doctor on a Friday in the U.S., let alone a weekend) To say that doctors are needed to prevent allergic reactions seems absurd, because all they do is ask you if you're allergic to any antibiotics, you say no, you take your chances. A minimum-wage store clerk can ask you if you have any allergies just as well, and could enter it into a database just as reliably for that matter.

I even find myself very skeptical of the truism that taking antibiotics for less than the full term causes resistance. We know what antibiotic resistance is - it's caused by the uptake of plasmids with the genes on them. The bacteria don't just re-invent the resistance by blind slow evolution, not in a few days in your throat. So either some of your bacteria have the plasmid, or none do, and so either some are unaffected, or none are. The only way I can see it mattering is in the edge case where you don't take down enough of the susceptible bacteria and so there is less immune system to bring to bear on the resistant ones; but if that is the case shouldn't you still feel sick? Still, that's a question, not an answer, because I know this statement is repeated everywhere antibiotic resistance is discussed. Wnt (talk) 19:41, 15 December 2014 (UTC)

Was that all just a complicated joke, Wnt? The source you give for whether they do actually sell antibiotics off the shelf in Russian says no such thing. What it does say is

It's not wise to get antibiotics over the counter - ) the one you get may not be the most appropriate for you b) the one you get may not be most appropriate for your problem and c) most importantly, your self-diagnosis may not be correct; you're best advised to see your doctor today and as well as a history being taken, have your chest listened to / examined so that the diagnosis can be made with certainty. Bronchitis can turn to pneumonia in some people / if not appropriately treated. Disclaimer: These comments are made for the purpose of discussion and should NOT be used as recommendations for or against therapies or other treatments. An individual patient is always advised to consult their own physician.

. Further, doctors don't simply ask if you are allergic to penicillin. They then apply that knowledge to avoid prescribing penicillin-analogs that might also cause a reaction.

Third, Taking a full course of antibiotics is recommended because, first, stopping when you feel better may leave a reservoir, possibly of bacteria which have become more resistant in your body and during the course of your infection (or do you think bacteria acquire plasmids over the counter?); and second, because the antibiotic may be affecting dozens of other bacteria in your body, weeding out some of the less resistant strains and leaving some of the more resistant strains. If the political goal is to weed out hypochondriacs from the population, I am all for your plan of eugenics. But as practical, non-fringe OR....? μηδείς (talk) 20:24, 15 December 2014 (UTC)

There is a group of people who acquire antibiotics through various channels: survivalists, aka doomsday preppers. I won't give you a lecture on legality, medical advice, etc. Search the web for e.g. survivalist antibiotics. Plenty of information and disinformation there. 88.112.50.121 (talk) 02:12, 16 December 2014 (UTC)

Biology is complicated. People spend years studying how the human body works and they still only have a vague idea of what's going on, but their views are probably more valid that your manicurist's. The drugs we have, have been shown to generally help people who are suffering from certain problems, but because biology is so complicated, it's still a crap shoot whether any particular drug will help you with your problem. Talking to a doctor is often a good thing to do because 1) they are generally fairly intelligent, 2) they know something about biology, and 3) their judgement isn't impaired by whatever is ailing you. Getting in to see a doctor does seem needlessly convoluted. I think it's that way to keep the riff-raff out (all those people who are not really sick). Drugs are restricted to enrich the medical establishment, not because anyone is worried by antibiotic resistance. That is a recent problem. Antibiotics have always been proscribed. — Preceding unsigned comment added by 50.43.56.168 (talk) 09:50, 17 December 2014 (UTC)

@81.138.15.171: There is also a possible financial reason for governments restricting sale of antibiotics, if they are subsidised by that government. Here in Oz we have the Pharmaceutical Benefits Scheme (PBS) which subsidises drugs including antibiotics. For example, some blood pressure drugs are about A$30 a box, but if you have a 'Health Care Card' (HCC) (unemployed, pensioner, disabled etc) they are only $6 a box. You do need a prescription to get them, though even if unsubsidised it is likely their sales is still restricted. Not sure, but I think medicines on the PBS schedule are still heavily subsidised to those without a HCC. With a HCC, and if your Doc 'bulk bills' it won't cost you anything to see them for the prescription. It's just another possibility. ¤ 220 of ^Borg 15:49, 20 December 2014 (UTC)

How many percents of the human blood are water?

Someone wrote on a Facebook group that 92% of the blood is water. I'm confused because of the hematocrit is about 45% of the blood. Maybe the the water includes the HCT? 5.28.177.164 (talk) 15:01, 15 December 2014 (UTC)

Blood#Constituents_of_human_blood indicates that of blood, 45% is red blood cells, white blood cells 7%, and the balance is plasma. One thing to remember is that this accounting is not an indication of the total water; remember that cells (including red and white blood cells) are mostly water as well (they are basically bags of water surrounded by a cell membrane). So, if you're asking what fraction of blood is water (and looking for a molecular analysis rather than looking at the breakdown I cite above), you're going to get a different answer. The 92% figure is for water in blood blood plasma: this site indicates that, and matches that number. There is a lower percentage of water in the cells, but they are still more than 50% water. I can't find a solid reference, but some uncited answers at places like answers.com and yahoo.com indicate that red blood cells are about 80% water, meaning that overall, your blood (including what is inside the cells and what is in the plasma) is in the high 80's for percentage of water. --Jayron32 16:39, 15 December 2014 (UTC)

Jayron32 thank you for the response. Do you not think that it's strange to not have even one article that talk about (the percentage of water in the blood)? I would never believe it if you don't say it.5.28.177.164 (talk) 01:56, 16 December 2014 (UTC)

Those figures seem to come from a study done in 1953: A Rapid Titrimetric Method for Determining the Water Content of Human Blood. (Titrimetric = measurement of the concentration of a solution) I would guess studies since then focus on parts of blood rather then on the whole. Richard-of-Earth (talk) 10:22, 16 December 2014 (UTC)

Rechard, Thank you! 149.78.45.16 (talk) 00:17, 19 December 2014 (UTC)

@5.28.177.164:/ @149.78.45.16: Here's another site at stanford.edu with lots of blood related facts. [8] Slightly lower % of plasma noted at 90 (vs 92%). (simplified for media use perhaps? ) 220 of ^Borg 01:19, 20 December 2014 (UTC)

What is the strongest organ in the human body, in all aspects?

5.28.177.164 (talk) 15:02, 15 December 2014 (UTC)

What do you mean by strong? Capable of producing a force of X Newtons? --Lgriot (talk) 15:10, 15 December 2014 (UTC)

And what do you mean by "in all aspects"? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:06, 15 December 2014 (UTC)

Lgriot and Bugs have valid points, but - the mechanically strongest bone in the body is the femur (thigh bone), the muscle capable of applying the greatest force on its own is the soleus (calf muscle), and the muscle with the best force-to-weight ratio (and the one capable of applying the greatest pressure, via the canine teeth) is the masseter (jaw muscle). But we'll need to narrow down "strongest" (and, indeed, "organ") to give you a better answer. Tevildo (talk) 22:15, 15 December 2014 (UTC)

The question's open until we get a better clarification, but I suspect the heart beats the rest. μηδείς (talk) 02:09, 16 December 2014 (UTC)

Oh, let's just guess. Eyes may have the strongest influence on social behavior. The stomach has strong acids. The brain has the strongest influence on how the body runs and what it does and while doing so consumes up to twenty percent of the energy used by the human body, more than any other organ. Richard-of-Earth (talk) 10:02, 16 December 2014 (UTC)

Where can I read about the influence of the gravity on the blood pressure?

In which the article here can I read about the influence on the blood pressure in different places in the human body (for example: if the blood pressure in hand is the same to the BP of the leg) 5.28.177.164 (talk) 15:11, 15 December 2014 (UTC)

A web search (Google, Bing, etc.) would be a good place to start. Short Brigade Harvester Boris (talk) 15:39, 15 December 2014 (UTC)

... which brings us back to our Blood pressure article, but it hasn't a lot of detail. Some other articles in Boris's search will provide more detail, depending on how technical the OP wants to get. Dbfirs 18:16, 15 December 2014 (UTC)

What do nutrient deficiencies tell us about early modern human diet?

Before the invention of iodized salt, before the invention of vitamin tablets, before the invention of calcium tablets, what did early modern humans eat to maintain a healthy, complete diet? 140.254.70.33 (talk) 17:16, 15 December 2014 (UTC)

Early humans ate seafood which contained enough iodide to keep them healthy and was also possibly what helped develop the larger brain.[9] Presumably as we migrated away from coastal areas iodine deficiency became a problem in some places but not such a problem that it wiped out whole populations or made them so unfit they were at an evolutionary disadvantage. Vitamin tablets and calcium tablets are unnecessary for most people if they eat a balanced diet - most people who take extra vitamins just excrete them in their urine. It is often said that the effect of most vitamin tablets sold is just to produce expensive urine! Hunter gathers ate anything they could get hold of - meat, nuts, fruit, seeds etc. all of which contributed to a balanced diet. Richerman (talk) 18:01, 15 December 2014 (UTC)

And humans can digest all of them. I'm trying to imagine how apes descended from the trees evolve the right teeth to tear meat. 140.254.70.33 (talk) 18:13, 15 December 2014 (UTC)

You've lost me now - are you asking about apes or humans? We don't have have teeth that can tear meat very efficiently - our teeth are more suited to eating an omnivorous diet with small pieces of meat such as seafood and insects, so we developed tools for killing and cutting up larger animals. Other apes diverged to become carnivores with massive canines for tearing meat without the use of tools but I would think that further back on the evolutionary chain they ate insects, seafood etc. as many still do today. Anyway, I'm afraid I'm just leaving for work so I'll have to leave it to others carry on with this discussion. Richerman (talk) 18:40, 15 December 2014 (UTC)

The bit about the iodine is interesting in an evolutionary sense. Looking at [10] figure 3.3, you can see there is substantial variation of iodine levels in Africa. It would seem reasonable to suppose that if you could guess the habits of human ancestors, you could use data like this to narrow down the range of early human ancestors within Africa. I've been suspicious that there could be a trove of ancient fossils somewhere near the Okavango Delta, since things like the elongated feet of the lechwe and the ability of clever hunters to feast on game killed in yearly wildfires or trapped in mud pits seem reminiscent of specific human adaptations. But generally the genetic data has been pointing further north, which is a big problem for that idea! It's interesting though that some of the regions to the north seem much too low in iodine... Wnt (talk) 20:19, 15 December 2014 (UTC)

It is worth keeping in mind that moderate malnutrition is survivable and in the past was very common. The average human adult increased about 4 inches in height since the 1850s, with most of that change attributed to improvements in childhood nutrition. It is likely that early humans often had a suboptimal diet. Access to nutrient rich foods would have been one of many factors that determined where people lived and which populations of early modern humans became dominant. It is likely that early humans didn't have a good understanding of their nutritional needs beyond simply trying to stay fed with whatever was available. Dragons flight (talk) 20:34, 15 December 2014 (UTC)

I second the above, where is any evidence that "early modern human" had anything close to a "healthy complete diet"? It's some sort of naturalistic myth that animals in nature live long healthy lives. Most animals born in nature have far less than a 50% chance of making it to breeding age, they get eaten, die of diseases or parasites or malnutrition, early modern humans would have been in the same boat. Vespine (talk) 21:59, 15 December 2014 (UTC)

The idea isn't that they had a "healthy complete diet", but that they should have adapted to be OK with the diet they have. For example, in the iodide figure I mentioned above, there are countries where the iodide level is optimal (100-200 ug/l iodine in urine), some where people get goiter from deficiency (some with <20), some where people have risk of iodine-induced hyperthyroidism (going to over 300 ug). Now the enzymes that take up iodide and conjugate it to thyroid hormone could be evolved to have higher or lower avidity, stronger or weaker vmax, or most likely, just higher or lower expression levels. So how did they evolve to be set where they are? Well, to make the diet optimal -- over a long time scale. That fine-tuning might shed a light on how things were for human ancestors, though admittedly, there's a big risk that the evolution is much faster than that, so that the ancestral state is forgotten; it is not unlikely to evolve as quickly as skin color, I think. But I don't know and I really doubt anybody looked yet. Wnt (talk) 05:47, 16 December 2014 (UTC)

• The higher primates; tarsiers, monkeys and apes, have lost the ability to produce Vitamin C. Given its essential nature, this means those animals must have gotten enough of it in their diet to survive. Hence the term Limey. μηδείς (talk) 02:05, 16 December 2014 (UTC)

That limey article is awful - they've used an answer from yahoo answers as a reference and got it all wrong. Lemon juice was added to the rum ration to make the lemon juice, which had been shown to ameliorate the symptoms of scurvy, more palatable. Looks like that's another one I'll have to rewrite :-) Richerman (talk) 18:13, 16 December 2014 (UTC)

Yes, it seemed they had it backwards. It was my memory that this was done purposefully to avoid scurvy that reminded me of the term. μηδείς (talk) 17:54, 17 December 2014 (UTC)

Do animals in nature just copulate among their peers?

Without human intervention, could one animal go after another animal of a different species?--Noopolo (talk) 18:30, 15 December 2014 (UTC)

Yes. Here is a recent example: (link to a BBC article) --Dr Dima (talk) 20:03, 15 December 2014 (UTC)

Thank God for human intervention, or this sort of unnatural behavior would be happening all over nature! Plus, copulation implies mutuality, not (inter)species rape. μηδείς (talk) 21:20, 15 December 2014 (UTC)

Once again, you're nitpicking ... but with a nitpick that's completely wrong. Whatever baggage the word "copulation" might carry when referring to humans, it's often used scientifically to refer to other species, even species where mating routinely involves force and an unwilling partner. The first such species I could think of off the top of my head was Mallard, and guess what? That article uses the word twice to describe a situation that is very much not mutual. APL (talk) 00:36, 16 December 2014 (UTC)

As I've chided Medeis and others before, it is totally unscientific to to talk about Mallard mating as "rape" or to claim that is in some sense not consensual. Ask any specialist in animal behavior and they'll agree. How do you know what a duck wants? Maybe she is thrilled to get chased around. Also, there is assortative mating and sexual selection that come in to play. From honey bees to bedbugs to ducks, animals mate in various ways, and there's little value in projecting our human notions of consent on to these dynamics. (Seriously, traumatic insemination seems weird compared to the human perspective, but if you call that rape you'll be declaring to the room that you are naive to the ways of modern biology.) SemanticMantis (talk) 18:17, 16 December 2014 (UTC)

Copulation implies uniting, joining; rape is usually described as forced penetration. (Consider: police officer: "So, ma'am, when you copulated with the rapist, did you happen to see his face?") I am not likely to take the fact words are used loosely or improperly by WP editors or elsewhere as of much weight. μηδείς (talk) 17:49, 17 December 2014 (UTC)

It implies no such thing when referring to animals. It is often used by experts completely contrary to the distinction you are making.APL (talk) 22:35, 19 December 2014 (UTC)

Then you probably shouldn't be making statements based on subjective assessments that invite equally subjective responses. Unless you have a source to support your assertion that the established definition for copulation as a clinical term involves consent as a necessary condition? Snow talk 21:55, 17 December 2014 (UTC)

It is usual for animals to copulate (for whatever reason) among their own species. However there are many reports available by internet search about inter-species copulation, as noted above. These incidents are rare compared to normal sexual behaviour, but they occur. Human intervention has little to do with wider natural sexual behaviour of animals and can be regarded as of little influence except where animals are kept in captivity and may be subject to stress by denial of natural species partners which may lead to abnormal sexual behaviour.

You may find Animal sexual behaviour of interest.

Medeis, you really need to edit properly so that your irony is clear. Richard Avery (talk) 08:14, 16 December 2014 (UTC)

Sometimes, yes. Other times, less so-- see founder effect, inbreeding depression, Allee effect, Naked mole rats are highly related to each other, while the Major_histocompatibility_complex is thought to be a factor in helping humans avoid mating too closely within a lineage. SemanticMantis (talk) 18:17, 16 December 2014 (UTC)

Oops, sorry I thought the question was about inbreeding as well as inter-species attempted copulation. I'll leave the links above though. More on topic to the actual question - here [11] is a very interesting example of interspecies 'mating' - this Amazon_molly fish reproduces by parthenogenesis, and only females exist. However, the females only reproduce when exposed to sperm from males of a different species, even though that sperm does not fertilize their eggs!

Capillary action in a tube of insufficient length in a gravity free space

What will happen to water when capillary action take place in a glass capillary tube of insufficient length in a gravity free space? Will it just come out of the tube and take spherical shape or water will simply overflow the tube? 223.176.157.81 (talk) 22:28, 15 December 2014 (UTC)

Is the outside of the tube hydrophilic or hydrophobic? What is the temperature? μηδείς (talk) 22:47, 15 December 2014 (UTC)

The tube is at a place where there is no planet, no mass. Let it be placed somewhere in general space (like halfway between earth and sun). 223.176.140.63 (talk) 23:13, 15 December 2014 (UTC)

NASA flew Capillary Flow Experiment-2 to ISS this year; STS-131 flew a related Capillary Flow Experiment in 2010; there have been many other similar research experiments on other space flights. Earlier flight results flew to International Space Station in 2003. I found this publication from the same group of researchers, and the Capillary Flow Experiment webpage maintained by NASA Glenn Research Center.

I also found Mark Weislogel's faculty and research webpage, which links to lots of video and photos from these experiments.

Among the many fascinating experiments, CFE and CFE-2 have specifically studied your exact question: NASA and its research partners are interested in studying the egress of fluid propellant from tubes in microgravity environments. Like everything in science, the answer depends on details, but hopefully you can read these websites to get some context for the answers that we do know!

Nimur (talk) 23:14, 15 December 2014 (UTC)

Sanity Test for Einstein's Train Experiment

Imagine a remotely controlled spaceship moves close to the speed of light [say 0.9c] relative to stationary observer on asteroid. For simplicity please click on the link. Reset the value of beta to 0.9 and then press the tab of “set value and play” of animation. Assume each mirror [shown in the light clock] has a firing gun and stopping detector such that source and destination points of a signal lies face to face separated by distance L’ in their respective clocks. Onboard observer fires a pulse from any of the shown mirrors and a space ship stop when it strikes its target on the opposite mirror.

Horizontal clock

Case #1: A pulse is fired from the back of ship towards the front.

For onboard observer: A pulse has already arrived at its front target and counterintuitive asteroid has just stopped in front of ship (L’=Ct) while

For asteroid's observer: A signal (pulse) will be still moving inside the moving ship due to ship’s high speed and yet to arrived at the front (L=Ct+Vt)

Case #2: A single is sent from the front of ship towards back

For onboard observer: A signal (pulse) will be still moving inside the ship and yet to arrived at the back (L’=Ct) while

For asteroid's observer: A pulse has already arrived at its back target and a spaceship has just stopped in front of asteroid (L=Ct-Vt)

Vertical clock

Case #3: A signal is sent from the floor towards ceiling target

Case #4: A signal is sent from the top towards the floor target

Case #5: A pulse is fired from each mirror simultaneously towards its face-to-face target.

So

Would the universal stopping position [coordinates] of spaceship be the same for both stationary observer on asteroid and onboard observer when spaceship comes to rest with the help of remote control device used by onboard observer in aforementioned scenarios?

After comparison on such similarity, would the global stopping coordinates [position] of the Einstein’s transparent train be the same for onboard observer and outside stationary observer if it comes to rest with the help of remote control device as explained above?

Would the universal/global stopping position [coordinates] of ships/ train (or asteroid) coincide for conflicting observers? 162.157.238.164 (talk) 23:06, 15 December 2014 (UTC)Eclectic Eccentric Kamikaze

You say that the ship stops when the light hits the detector, but the gun and detector are both inside the ship—implying that the light travel time across the ship is significant—and any mechanical process that stops the ship is subject to the same speed-of-light limit as everything else. It can't stop instantaneously. You could probably work around that by making the ship much smaller and having it contain only the detector. You also didn't specify what triggers the gun. That's important since it affects where the ship stops relative to the asteroid. To the problem as stated, the answer is basically that the gun fires earlier (in case 1) or later (in case 2) in the rest frame of the asteroid than in the rest frame of the ship. -- BenRG (talk) 04:10, 16 December 2014 (UTC)

Addendum: Although its not necessary but it may bring more clarity in case#1 and #2.

A similar defect would find by the onboard observer in the asteroid’s clock due to the mirror situation, therefore, although onboard observer has just stopped in front of the asteroid but according to theory, an asteroid would be still moving (due to his counterintuitive uniform motion) as a pulse would be still moving inside the moving clock (which is stationary on asteroid) and yet to arrive at the target (if mounted with decoy source and target) for him.

Conclusion: Both observers became to rest relative to each other but not according to the theory of Einstein. So is it possible?

I don’t think a sudden stop or stopping from declaration would affect sanity check.

Further it is added that although the velocity of bolt is C for the onboard observer of train but at the same time he also observes that outside observer (although stationary)/ surrounding is either moving away or toward him with Vt. Thus L for onboard observer relative to the motion of outside observer (stationary)/ surrounding is either L=Ct-Vt or L=Ct+Vt (where Vt is velocity of train/ship). 162.157.210.127 (talk) 00:05, 18 December 2014 (UTC)Eclectic Eccentric Kamikaze