Wikipedia:Reference desk/Archives/Science/2015 January 23

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January 23

Gross hamster tumours

A number of our dwarf hamsters have a strange belly bubble. What I find on the internet does not match. It can develop at any time. It is redish and may sometimes burst (yuk!). It can be the size of a big olive. Sometimes the hamster dies -- sometimes not. Also, some hamsters get small and then die -- hamsters without such bubbles -- but maybe that is related. Anyway, what is this bubble disease? I can't even figure out what type of thing this is? Anna Frodesiak (talk) 01:19, 23 January 2015 (UTC)

Anna, are these "bubbles" located in the same part of the belly of each hamster or more variable? My first inclination from your description is that these are abscesses (especially given that they "burst"). Do you have mixed sexes and ages in one enclosure? How much space do they have? In many such species the most common cause of abscesses are bite wounds that heal over, sealing bacteria inside where it grows, prompting the immune response which develops the abscess to fight the infection. The only reason a hamster would get noticeably smaller in a short period would be serious ailment and/or malnutrition from depressed appetite. This could also be a sign of an infection. I suspect that you may have too many animals (and/or a problematic combination of sexes and maturity levels) kept in one enclosure to ensure safety and hygiene amongst them. For the time being, if possible, I would isolate each animal separately or in small groups. Completely clean every inch of surface in each living environment with an antibacterial solution that is safe to use in the presence of animals before you place any animals within it.

If your animals develop any of these further "bubbles" (by the way, if they smell like death when they burst, it's an indication they very well may be abscesses) there's nothing to be done but to take them to the vet, as, if they are abscesses, an antibiotic is called for. Honestly, though, I think a vet is who you really want to be talking to about this right now anyway; there seems very likely to be an infection of some sort being shared amongst these animals and nipping it in the bud now by getting basic treatment for them and changing up their living environment will save you money in the long run, save them a great deal of suffering, and reduce the risk they might pass on an infection to someone in the household. Besides which, these might not be mere abscesses at all. For the well being of you and your pets, I daresay it's time to bring in the professional. Best of luck. Snow talk 01:48, 23 January 2015 (UTC)

Thank you so much for the thoughful reply. Some answers to your questions:

• Sometimes under the chin. Sometimes down low in the belly.
• Yes, mixed sexes and ages in one enclosure.
• Lots of space.
• No bad smell when they burst.

More facts:

• Sometimes when they fight, they bite each other in the stomach.
• In the glass tanks, we use sand that we get from here and there -- mostly constructions sites.
• There are lots of rats where I live (Haikou).
• Going to a vet here will result in two things: 1. The vet will have no idea what he's talking about and just make guesses with an air of authority and certainty. 2. He will try to sell the most expensive medicine he has, which might actually be water.

From what you've said, I think it best to pour a bottle of rubbing alcohol into the sand bags a week before using them because this may be rat poop-related. Any hamsters that fight will be isolated. We will try to diversify their diet, which now consists mainly of sunflower seeds, peanuts, sesame seeds, greens, and bits of cheese if they're lucky. So, what about teeny amounts of antibiotics? Anna Frodesiak (talk) 02:08, 23 January 2015 (UTC)

I had no idea the state of local veterinary care was so dismal there -- that's unfortunate. Well, I'm hesitant to give any kind of firm analysis without firsthand observation, but all the circumstances do seem to point toward issues with bacteria. Addressing some of your further info: lack of of smell doesn't necessarily rule out abscesses either, in that this varies depending on the type of bacteria, size of the abscess and so-forth. Definitely if you are not using pre-packaged and sanitized sod/sand product, your idea of sanitizing the sand best you can on your own is worth exploring (not just the feces of other animals, but any number of other sources of bacteria can be found within typical sand), though striking the right balance on how much solution to use may be an issue; I'd recommend wood shavings instead, but rodents need these to be made of specific materials to avoid toxicity issues, and I'm not sure what the consumer market looks like for variety in pet products thereabouts. Honestly the diet you are feeding them now seems pretty decent all-around, but more diversity can't hurt either; there are many forums online which can give you hints as to what your specific breed of hamster would like, I've no doubt.

I'd be very concerned about trying to self-administer antibiotics, as small rodents are notoriously difficult to dose; too little and the infection can rebound and even become worse while too much and the animal can easily have a reaction and die immediately. I'm in consultation with my fellow editors on this matter right now, trying to determine just how much I can say here; we have a policy against direct medical advice and I need to gain consensus with them about whether it extends to veterinary advice before I speak too much to the subject of antibiotics. For the time being, I think the preventive measures you've discussed above will be a good step in the right direction; get the serial biters away from the others and increase the frequency of cleanings (don't forget to use gloves, a mask and and a thorough cleaning of your hands and any other exposed areas both before and after the cleanings to reduce risk of cross-contamination between you and them). I also know that in some species of hamster (dwarf and otherwise) aggression is tied to breeding conditions with fights over mates, between mates, between mothers with competing broods, and all other manner issues. I'd look into the mating habits of your particular species to try to determine what the best combination of individuals is, with regard to the ages and sexes in a given group.

Do you have any animal showing an abscess now? If so, I would isolate that one as well, regardless of whether he or she seems to be a fighter and give them some special care. Observe whether they eat or drink and try to encourage them to do so if they aren't. You can try to bring the abscess to a head by applying a warm, wet towel to it for 10 minutes every hour (be sure it's not so warm as to burn their skin though). If it does burst, flush the area out with a mixture that is one-part hydrogen peroxide (if you have it handy) to eight parts water and make sure it stays open so that it heals from the bottom up. Moving forward, any time you catch the animals fighting, separate them and check them over for wounds (this can be tedious, as the hair tends to obscure them, but finding them earlier will make things much easier on you). Clean any wounds found with the same solution recommended above; there are also topical antibiotics that you can buy with a nozzle which allow you to push the ointment into the wound to hopefully prevent and abscess from forming in the first place, but I don't know where you'd get them there, short of a vet. In any event, these are definitely "an ounce of prevention = a pound of cure" type situations with these animals. Snow talk 03:09, 23 January 2015 (UTC)

A less expensive and less toxic way to sterilize sand might be to boil it. StuRat (talk) 04:48, 23 January 2015 (UTC)

I'm doubtful that would be cheaper (and certain that it would be a lot more work), but it could be more hypo-allergenic friendly to the hamsters. Snow talk 06:16, 23 January 2015 (UTC)

Hi StuRat. Thanks for the advice. Unfortunately, boiling would mean drying, and that's just way too much to do. But thank you. :) Anna Frodesiak (talk) 06:38, 23 January 2015 (UTC)

• I think they don't like wood shavings. It's too hot and I've read that it gives them other health issues.
• I'll avoid antibiotics for now. Don't worry about medical advice for hamsters. Life is cheap when you're a hamster and they get a pretty good life here. Good food, lots of love, decent lifespan, food delivery service, no owls.
• I'll try the forums, but I just tried one and got a malware warning. (See my contribs for links removed from a few pages.)
• The fights are usually adolescent sibling rivalries and husband-wife disagreements. Nobody else fights. We'd never normally put two adult males together.
• One named Silverback has an abscess right now. It's huge and so is he. He is very old and his wife is getting smaller.
• Could it be inbreeding? Everybody comes from seven individuals a couple of years ago (probably related to each other). There is also Trippy. No abscess, but born with his front right leg missing. It's there, but under his fur. He sort of uses it. It's like when you can't find the armhole for your sweater. Also, his ex-girlfriend bit out his right eye. We think he secretly hates his right side. But he's a good sport about it.
• Everybody eats and drinks just fine. (No waterbottle. Just cucumber.)
• Nobody is willing to put a wet towel on the thing. It's too gross. And if it bursts, nobody will even pick him up for a while. I can promise you that. Anna Frodesiak (talk) 06:38, 23 January 2015 (UTC)

Bit out his right eye huh? Yeah, I had a break-up like that once... As to inbreeding, I think the effect that would have on the propensity for abscesses (aside from the fact that it could, possibly, lead to more aggression between the offspring) but you may continue to see more congenital disorders if they continue to interbred; since it seems you keep a number of these critters at once, it might not necessarily be a bad idea to add an outsider or two for new blood for the over-all health of the population. Of course that carries its own risks (possible new outside infections and the possibility the current clan won't take well to the newcomers. And yours would not be the first population of rodents to descend from just a handful of individuals; animals that have "broods" are a little bit better adapted to handling the genetic issues implicit in this situation. I wouldn't worry too much about the forums; I think the diet you are offering them is pretty diverse and unlikely to be a factor in their problems.

And it sounds like you have them as separated as ideally as possible, so there's little more you can do I suppose about the fighting other than to stop it when you see it and keep anyone who can't get along separate. I'd say the best single thing you can do is try to clean out the wound when you see one get bit; even more so than disinfecting the sand and the living space, this will help prevent the abscess from forming in the first place (if indeed they are abscess - I'm fairly sure they are from your description of the circumstances, but it's worth remembering this is a long-distance assessment). I would look into a topical antibiotic for this purpose, but again, that might necessitate vet involvement. If I find I can be more specific on that topic, I will post a follow-up on your talk page. In the meantime, good luck to you and the little furballs. If there's any other guidance we can provide, do let us know. Snow talk 08:25, 23 January 2015 (UTC)

• Not really "bit out", but bit, closed, and never re-opened.
• Sorry about your break-up. During a break-up, it is probably best to wear safety goggles, and maybe a helmet too. (Although, if you sit down to announce a break-up wearing those, your significant other will totally see it coming.)
• We are looking for an outsider. They tend to die from being pre-poisoned. Bunnies, puppies, etc., all seem to last only a month or so before dying. I guess the sellers don't want to make a glut.
• Young newcomers go well with other young ones. Adult females can be introduced to males, but it is best to rub stinky bedding all over them first so they smell familiar. Another trick is to put them into the tank in a cardboard box with big holes. Both sides work to enlarge the holes to "get at each other". By the time they break through, they're friends.
• It's hard to spot wounds, but that's a good idea to find and clean them.

• Many, many thanks for the advice, by the way. Anna Frodesiak (talk) 09:49, 23 January 2015 (UTC)

You're most welcome! Snow talk 10:46, 23 January 2015 (UTC)

We shouldn't be giving "advice" - you may or may not get useful information here, but the decision making is up to you. We do not issue a hamster back guarantee! And I might find it an 'interesting experiment' to evaluate the LD50 of antibiotics in dwarf hamsters empirically. You may find [1] interesting with a list of antibiotics - to be honest I got that from Google, due to the popularity of hamsters in science PubMed is not very usable for this! Oh, and though I shouldn't give advice, please do be careful - if there are infectious bacteria involved, they might pose a hazard to you. Wnt (talk) 15:47, 23 January 2015 (UTC)

Really, don't worry. We're talking about hamsters. :) Besides, things can't get worse. Silverback's bubble is 10% of his body weight. It's revolting. We thought it was a botfly larvae at one point. Anna Frodesiak (talk) 23:40, 23 January 2015 (UTC)

Is there any science source about the influence or damage of opiates on the kidney / liver when it's used for a long-term

Is there any science source about the influence or damage of opiates on the kidney or liver? 5.28.146.113 (talk) 04:56, 23 January 2015 (UTC)

[2], [3] (scroll down to the bottom for peer-review references), [4], [5]; opinions seem to vary some and, for obvious reasons, the answer is largely circumstantial, depending on the over-all health of the individual, length of abuse, predispositions, and all other manner of factors. One point to bear in mind in this case is the distinction between direct and indirect causal factors. Even in cases where specific opiates themselves do only moderate damage, they are often combined with other pharmaceuticals that take a higher tole on renal and hepatic tissue. What's-more, those with opiate dependencies are often far more likely to suffer specific kinds of infections that can lead to organ damage. Snow talk 06:14, 23 January 2015 (UTC)

Thank you. But I think three of them are not scientific sources, I knew them before by googling.5.28.146.113 (talk) 09:10, 23 January 2015 (UTC)

Nope. Indeed, three of them are not all peer-review, but I didn't anticipate that you would want only such sources. The first is peer review, the second is the least formal, in that it it's a narcanon page, but even it has ten references which are themselves all peer-review research on the topic, the third is a transcript of five doctors collaboratively answering just your question (which would be an ideal source, if not so brief) and the fourth is part of the online resources of the National Institute on drug abuse. If you want explicit primary source research only, the second listing (or rather its reference section) is your friend. Perhaps it would help if you told me what this is for? If you need to be able to cite sources of a specific type for example, I can help you find more of that variety. Snow talk 10:00, 23 January 2015 (UTC)

• Opiates are a very broad class. I suggest you look up the specific drugs you are interested in and look at their toxicity and ld50. For an analogy, compare the toxicity of ethanol and methanol, which are both alcohols. μηδείς (talk) 06:45, 24 January 2015 (UTC)

What are the proximal organs?

5.28.146.113 (talk) 09:05, 23 January 2015 (UTC)

Proximal is not really a class of organ, per say. It's a relative anatomical term, with a lot of different meanings along a similar theme of being "closer to"; it contrasts with "distal", meaning "farther from". So, for example, the fingertips are less proximal to the torso than is the elbow; the toes are more distal to the torso than are the knees. When used to refer to organs, proximal can have a couple of different meanings depending on context. It can be used to refer to a part of an organ that is is closer in some sense to the center of the body and other organs it connects to (for example, the proximal colon or the proximal end of the esophagus) or it can refer to relative positions of the organs or to indicate direction in general. And then there are still more abstract uses with regard to metabolic and systemic pathways. The shared elements are that proximal means "closer to" or "towards" whereas distal indicates "farther/away from". Snow talk 10:22, 23 January 2015 (UTC)

• Its not perfectly defined, but in context, proximal and distal usually mean closer to or further from the spinal column, heart, and stomach, each as the "center" of its own system. (Of course the spine is distal to the brain, so it's vague in layman terms.) Again, this can change by context. When my father had knee replacement (I had to take three days off and drive almost 1,000 miles) the hospital, which was excellent, offered a family consultation. They tried in vain to explain clearly what sort of swelling and bruising was expected, and what wasn't. I finally said, anything distal from the knee is bad, and needs immediate attention, but proximal bruising is okay? They were surprised, and confirmed that yes, symptoms from the wound towards the toes were of immediate concern, but that minor symptoms from the knee to the hip were to be expected. μηδείς (talk) 06:56, 24 January 2015 (UTC)

Question about spaceships?

Non science guy here. On real life and realistic scifi. If you are at an travelling on space using an spaceship with max power and at an speed of X on space and turn off the engines, the ship will continue to travel with speed of X.
Lets imagine that some amount of time you turn on the engine to max power again, the ship will increase the speed or continue with the same speed of X?201.78.152.131 (talk) 15:39, 23 January 2015 (UTC)

Simple answer; turning the rocket motor on again will impart an acceleration - if you trust posigrade (in the direction of flight), your rocket will gain speed. Boils down to the fact that v=a*t (velocity equals acceleration multiples by time).WegianWarrior (talk) 15:47, 23 January 2015 (UTC)

That depends:

1) Current ships would increase speed if the engine was turned on (unless the spaceship had been turned around, then it would decrease speed).

2) The speed of light is the theoretical maximum, so while it would still increase speed, it would do so at a decreasing rate until you'd get to a point where no measurable speed increase would occur. Of course, we are nowhere near being able to go that fast yet.

Note that I am assuming the ship is in a perfect vacuum. There are some particles, even in space, so the spaceship will slow down by a tiny amount as it hits those, especially at higher speeds. Then there's the solar wind and radiation pressure, which blows anything away from the Sun, again at a very slow rate. StuRat (talk) 15:53, 23 January 2015 (UTC)

This means with an 1km per hour engine turned on and an extreme amount of fuel, you will "eventually reach speed of light?"201.78.152.131 (talk) 16:50, 23 January 2015 (UTC)

To put it in another way, in the older models (newtonian physics), as long as you apply engines, you will theoretically accelerate (gain "speed", more accurately, velocity) every time you apply engines.

In relativistic physics, it depends on who is measuring.

A. To an observer from your starting point, the closer you are to the speed of light, the more your acceleration appears to slow down, until it becomes almost (but not quite) zero at just below the speed of light. So you appear to reach just below light speed and stay there, never accelerating beyond that.

B. To the pilot, you will continue to accelerate at the normal rate as long as you apply engines, but the universe will begin to age faster around you. So no. Time will end before you reach light speed. :D

And yeah, this is given a magic spaceship in a perfect vacuum, not real spaceships in real space.-- OBSIDIAN†SOUL 16:13, 23 January 2015 (UTC)

One key concept is relativistic mass. The closer a ship is to the speed of light, the heavier it is relative to the 'stationary' observer. So to keep going faster relative to that observer, it takes more and more fuel for a given amount of acceleration. (this is basic F=ma, the acceleration from a given force is divided by the mass) Another way of looking at it is that suppose you look at a ship going half the speed of light in the right lane, and that ship is passed by one going half the speed of light relative to it in the next lane, and that ship is passed by one going half the speed of light relative to it, and so on. Is this possible? Absolutely. But none of these ships looks like it's going faster than the speed of light even to the 'stationary' observer. From the perspective of the ship, the same amount of fuel always provides the same amount of thrust ... but all that thrust never adds up to lightspeed from any perspective. Wnt (talk) 16:11, 23 January 2015 (UTC)

Sadly, no, it doesn't. Relativity will induce time and space dilation so you'll never reach the speed of light.

It's true (at any speed) that if you accelerate your spacecraft to speed X and turn off the engine, you'll continue to coast along at speed X for eternity...and If you turn the engine back on, you'll go faster, so as long as you have fuel left to keep the engine running, you can always go faster and faster. That's clearly true at speeds much less than the speed of light - but when you get close to light-speed, things get kinda complicated and you have to start asking who is measuring the speed and what they are measuring it relative to - and the answer gets very weird. (Basically, from your perspective, you'd feel yourself accelerating - but time and distance in the outside world would start to distort to prevent you from getting where you're going any faster than lightspeed. From someone else's perspective, they'd see time inside your spaceship start to distort to prevent you from getting to lightspeed.)

This business of the spaceship continuing at the same speed with the engine turned off is in accordance with Newton's laws of motion - but it can be counter-intuitive. After all, if you turn off the engine of your car while traveling at speed down the freeway, you'll gradually slow down and eventually stop. But that's because cars have friction against the ground and drag though the air. A spaceship (in a vacuum) has neither of those things. (Technically, space isn't a *complete* vacuum, there is always some teeny-tiny trace of gas and dust - so after hundreds of years, you'd gradually notice a slight slowdown).

In a car, when you're driving at constant speed, the engine is providing just enough power to overcome drag and friction. If you had a frictionless road and no air - then your car would coast forever with the engine turned off too.

SteveBaker (talk) 16:21, 23 January 2015 (UTC)

Steve, the drag though is very small unless you're going faster than bodies in that part of space, over easily obtainable spacecraft speeds, or very close to a visible atmosphere. Vanguard 1, a 3 pound ball carrying radios with antennas sticking out, has passed 0.05 Earth sizes from this world over 99,000 times and all it did was shrink the orbit from 17379 km in width to 17242 km (less than 0.8 percent). The percentage it was slowed down by was even less. I've never heard of drag being a factor for the smallest observable asteroids going 20 miles per second. Interplanetary spaceships can be shaped like flying junkyards.

If you travel at 67 million miles per hour between the stars (1/10th the speed of light, not too easy in the near future) then spaceship streamlining starts being important, though. In fact, at 604 million miles per hour (90 percent the speed of light) spaceships have to be thin, sleek, and protected by a heat shield. (though a lot of that is due to relativity, you're really reaching energies well over 90% the speed of light at that point but relativity speeds up or slows down others' time compared to you as appropriate so that nothing ever moves 671 million miles in an hour). Sagittarian Milky Way (talk) 22:49, 23 January 2015 (UTC)

Yeah - as I said "after hundreds of years, you'd gradually notice a slight slowdown"...and after just 57 years, we are indeed noticing a slight slowdown of Vandguard 1. It's certainly not very significant though - and the further you are from planets and stars, the less noticable it'll be. I merely wanted to point out that there is nothing materially different about the way a spacecraft moves compared to (say) a car. It's just a matter of degree. SteveBaker (talk) 23:09, 23 January 2015 (UTC)

How did humans form a diet that relies heavily on the consumption of carbohydrates?

How did humans form a diet that relies heavily on the consumption of carbohydrates? Around the world, foods rich in carbs may take on the form of rice, porridge, noodles, bread, and potatoes, and many of these carb-rich foods become staple foods. Yet, some humans can live on primarily carnivorous diet, and some humans can live on primarily vegetarian diet. Eh? How does that work out prior to the modern understanding of nutrition? 71.79.234.132 (talk) 16:51, 23 January 2015 (UTC)

If everyone tried eating only meat and vegetation, there wouldn't be enough for everyone. Bread's filling. Easy to catch. Tastes pretty good, too. Plus, it gives you an excuse to make beer. Beer gave nomads the reason they needed to settle down. Settling down created the ecosystem and population you see today. That required a lot of cheap starchy foods. Brewers have to eat, too, and more and more are too fat and drunk to hunt. InedibleHulk (talk) 17:15, 23 January 2015 (UTC)

Tell me that you are only being facetious by that flippant explanation. 71.79.234.132 (talk) 17:29, 23 January 2015 (UTC)

Nope. It's a bit overgeneralized, but human evolution's a long story. Others will be along with the finer details, don't worry. InedibleHulk (talk) 17:36, 23 January 2015 (UTC)

Hunter-gatherers, living off of e.g. Bushfood probably didn't might not have eaten as many carbs as we do, but it's hard to tell, because we don't have their recipe books or records of what they could find each day. Most experts think the diet was highly variable. But then the Neolithic_Revolution happened, at it became easier/more reliable to grow lots of carbs. Paleolithic_diet is more about the modern fad, but does have some info on what we thing prehistoric people ate. Paleolithic#Diet_and_nutrition has some other info. You might also be interested inNative_American_cuisine#Crops_and_ingredients - though there were many different lifestyles, and some of those people were very agrarian, while others were more like hunter-gatherers. SemanticMantis (talk) 17:38, 23 January 2015 (UTC)

(ec) I saw an explanation on a PBS pledge drive show, but some of those aren't reliable, so take this as a possible explanation only:

Humans are not well adapted to live on a diet heavy in carbs, particularly grains. In a "natural diet", they would only be a minor component of the diet. However, during the agricultural revolution, people found ways to grow complex carbs (starches) like grains and tubers (potatoes, yams, etc.) in quantity, and our diet switched to largely carbs, which made many more calories available to us than in a more natural diet, and fewer of some important nutrients (especially in the case of white flour). This has led to obesity, diabetes, heart disease, and other health problems. Simple carbs (sugars) have been refined more recently, leading to even more health problems. StuRat (talk) 17:45, 23 January 2015 (UTC)

Way easier to keep the carbs fresh, year-round, too. Ice wasn't big in the "known world" once, and salt wasn't exactly cheap. Needed a lot of something for all those mouths. InedibleHulk (talk) 17:58, 23 January 2015 (UTC)

(edit conflict)I don't think it's that simple. Tubers, especially things like wild yams, are an important element of human diet, especially for hunter-gatherers. And grains formed a very important component of the pre-Neolithic diet in the Middle East. Of course, both of these are seasonal foods, so they aren't likely to be a year-round food for non-settled people.

More fundamentally, grains, pseudocereals (quinoa, buckwheat, amaranth) and starchy staples (root, tubers, plantain, breadfruit) produce more food per unit area than do other crops. So they're critical components of any sort of agricultural intensification. But I think it's pretty safe to say that starches have always played an important part in the diet of humans - if memory serves me, the robust australopithecines (while not direct human ancestors) fed mainly on the starchy roots of grasses. Guettarda (talk) 18:05, 23 January 2015 (UTC)

People who think our ancient ancestors didn't eat many carbs have probably never tried to feed themselves by hunting with a pointy stick, or running game to exhaustion. Plants don't generally run away when you try to kill them. One often overlooked source of protein and fat is juicy grubs, but those also take some decent time and skill to harvest, and tend not to occur in very high densities. Of course there is a big difference between eating a raw yam and highly processed white flour. SemanticMantis (talk) 19:52, 23 January 2015 (UTC)

You're forgetting some major food groups, like fruits and vegetables. Those tend to be packed with nutrients, relative to the number of carbs (especially back then, before we bred all the fruit to have more simple carbs, AKA, sugars). StuRat (talk) 00:04, 24 January 2015 (UTC)

I think more crops are fed to livestock than eaten by people. A ton of animal costs 10 tons of plants to make. Doesn't that look slightly wasteful? I wouldn't want to see the habitat destruction caused by more protein in the average world diet. Sagittarian Milky Way (talk) 19:57, 23 January 2015 (UTC)

• I'll add staple food since I don't see it. Basically, consuming carbs from plants removes one level from the food chain (eat what the antelope eat, not just the antelope) and allows you to become much more plentiful. μηδείς (talk) 19:59, 23 January 2015 (UTC)

Staple food was in the original post, by the way. 71.79.234.132 (talk) 23:39, 23 January 2015 (UTC)

Yes, but there's a huge difference between knowing a term and looking it up. I suspect 2/3 of our questions would never be asked if the OP's would use the search and archive functions. Time also to restore "have you tried a searc engine to the policy at the top of the page. μηδείς (talk) 06:42, 24 January 2015 (UTC)

There is also a huge difference between looking it up on a Wikipedia page and actually looking it up from one's knowledge bank in one's head. The former may not always provide accurate, verifiable information, especially when the pages are not properly cited, while the latter requires an answerer to gather related materials in the mind and formulate a meaningful, brief answer, preferably with links to the desired resources. When you ask a quick question to a teacher, the teacher may (1) directly answer the question (even though that may not really be helpful) or (2) provide a list of links and references for finding the information that you didn't know before. 71.79.234.132 (talk) 14:13, 24 January 2015 (UTC)

I must note that answering a question may depend on how specialized the question is and how knowledgeable the answerer is. If the question is very specialized in scope, and the answerer does not have the topic as a field of expertise, then the answerer may find references, but the references won't exactly be on-topic or helpful. In this case, such a specialized question can serve as a knowledge litmus test to distinguish among "easy questions", "difficult questions", and "questions-that-humankind-does-not-know-yet". 71.79.234.132 (talk) 14:22, 24 January 2015 (UTC)

There is a growing body of evidence that it all started with beer. Once mesolithic humans had worked out the fermentation thing, they had to settle down to grow the grain. Then bread came along, the neolithic revolution, the rest is, what's the word? Fiddlersmouth (talk) 20:04, 23 January 2015 (UTC)

Hey, that was my top Google link! All good, though. Gave me a reason to replace it with a more suitably flippant and facetious one. InedibleHulk (talk) 13:47, 24 January 2015 (UTC)

While the semi-legendary "Eskimo diet" may have worked once or twice, the seal eater of today (literally) supplements his family's diet with starchy Frosted Flakes and Corn Pops, and it still isn't enough. They are also drastically underbeered. InedibleHulk (talk) 13:47, 24 January 2015 (UTC)

Is this a valid scientific method?

I want to know an answer to a question. So I think and think and think about it and I came up with a method to determine the answer. I want to know if my method is a scientific method for determining the answer to the question.

Do adult women get the same erotic arousal as men when watching the same "movie clip"? In other words, do men and women feel the same erotic arousal from the same stimuli?

I proposed to have an open competition where by film makers make a 20 minute film clip (sound and vision). This film clip is then shown to an adult audience of age 20 to 40 years. After watching the film clip, the audience must answer only one question. "On a scale of 0 to 10, where 0 is not erotic and 10 is the most erotic film you have ever watched. How erotic did you find the film clip?".

Next give the result back to the film makers and ask them to predict the gender of the audience. For example: Audience #324 gives the result 6 on the erotic scale.

Then determine how well, the film makers can determine the gender of the audience. 172.56.32.205 (talk) 17:04, 23 January 2015 (UTC)

I see a couple problems:

1) People might very well identify something as erotic that they don't personal find arousing. Instead you should ask if they personally feel aroused, if that's what you're interested in.

2) The last part (having film makers predict the audience member gender) seems extraneous. Just look at the scores directly.

And, in case you don't know this, men and women find different things stimulating. For example, most women probably don't want to see genitals, at least not right at the start. StuRat (talk) 17:55, 23 January 2015 (UTC)

I'd be surprised if Masters and Johnson (or their Institute) hadn't examined something like this question at some point, but I'm not going to search for references from my Office PC! {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 18:52, 23 January 2015 (UTC)

Yes, lots of research has been done on this topic, see e.g. [6], [7], or just this google scholar search [8]. A lot of the modern stuff skips surveys altogether and instead uses things like fMRI to do brain imaging. If you specifically want survey methods, try here [9], which is a meta-analysis of many survey-based studies. OP would be well-served to examine previously vetted methods, rather than making up a novel one (which has many problems). I should also point out that most of these studies are interested in the question of whether men and women have different or similar reactions to visual stimuli in general. If you really wanted to just test whether men and women had the same arousal from one specific clip then the methods will be a little simpler. SemanticMantis (talk) 19:46, 23 January 2015 (UTC)

What can't be modeled in science with differential equations?

I mean physics mainly.--Senteni (talk) 20:49, 23 January 2015 (UTC)

The main thing that comes to mind is turbulence. Differential equations are used to study it, but they don't really model it. Shock waves are also problematic, as they involve discontinuities, but they are typically handled by sort of augmented differential equations. Looie496 (talk) 21:14, 23 January 2015 (UTC)

Depends on what you mean by "differential equations" and "model." Numerical solutions of coupled partial differential equations are one of the standard tools for studying turbulence. Let's see if direct numerical simulation is a blue link. Short Brigade Harvester Boris (talk) 03:05, 24 January 2015 (UTC)

It's often not about whether something can or cannot be modeled with differential equations, it's whether that's the best tool for the job. For instance I use lots of stochastic finite difference equations in my research. I could probably use stochastic PDE, but that wouldn't work as well for analyzing systems that basically work in discrete time (e.g. populations that reproduce once per year.) Another example is how you can see the heat equation emerge from random walks - they both get at the same physics, but one is PDE and the other is not.

In pure physics, you have things like the Ising model, which doesn't really work well with DiffEq. Some methods in statistical mechanics don't use much DiffEq. Game theory hardly ever uses DiffEq, and has applications to economics, ecology, and social sciences. Then there's the stuff they do with Self-organized_criticality a very physics-y topic, which historically came about through the study of cellular automata and fractals, which tend to use few differential equations. These are just a few things that came to mind, I doubt there's any exhaustive list :) SemanticMantis (talk) 21:26, 23 January 2015 (UTC)

From a purely practical point of view, problems dealing with Concurrency and NP-complete models, like network flow. Bottom line - anything you can't reduce to a Polynomial. Fiddlersmouth (talk) 02:30, 24 January 2015 (UTC)

It's a trick question as nearly everything over an arbitrary space/time can be modeled. The degree of difficulty is the range over which the model is valid. Models describe what we observe but it's rarely true that what we observe is described exactly by a model over every possible condition. The model is bounded by and with error. --DHeyward (talk) 20:33, 26 January 2015 (UTC)

Ideas for Chemistry Paper Topic?

I have to write a lengthy literature review paper for a chemistry class. Does anyone have any ideas for a topic? I am looking for a topic that is interesting (perhaps involving a mathematical component), current, and will have ample journal review articles. Thank you. — Preceding unsigned comment added by Pinterc (talk • contribs) 22:26, 23 January 2015 (UTC)

I'd suggest the Belousov–Zhabotinsky_reaction. There's some very interesting history of the "supposedly discovered discovery" - the tie in to biochem with the Krebs cycle, and lots of cool math with the dynamics of reaction-diffusion systems. Also an interesting example of self organization and emergent phenomena (if you think of the thin-plate situation that forms spirals). Plenty of papers have been written on the topic, and the Brusselator and Oregonator models are an interesting illustration of how different models can say different things when different levels of complexity are included. If you can manage a demonstration, that's always a crowd pleaser :) Should be plenty of refs in those articles to base a review paper on. SemanticMantis (talk) 23:24, 23 January 2015 (UTC)

Oops, I didn't notice "current" - a lot of this research is not especially recent, but people are still publishing on this and related autocatalytic reactions. SemanticMantis (talk) 23:28, 23 January 2015 (UTC)

You didn't say if this is organic or inorganic chemistry. For organic, maybe something on protein folding, such as misfolded proteins/prions. For inorganic, maybe the search for high temperature superconductors ? StuRat (talk) 00:31, 24 January 2015 (UTC)

Suzuki reaction? Metal-organic framework? Plasmic Physics (talk) 02:11, 24 January 2015 (UTC)

There's been a lot of recent active research in nanoparticle drug delivery. --Jayron32 03:55, 24 January 2015 (UTC)

Graphene comes immediately to mind. Looie496 (talk) 16:14, 24 January 2015 (UTC)

• Coal-to-liquid might be a hoot. For the more biochemically inclined I'd like to know what ever happened to cellulosic ethanol. Wnt (talk) 16:27, 25 January 2015 (UTC)

What do you find to be "interesting"? If you find it interesting, you will have an easier or less onerous-feeling task. What any of us might find interesting might be in a field you don't care about, or that seems esoteric/specialized in a way you don't have time or interest in getting up to speed as a field. DMacks (talk) 03:59, 26 January 2015 (UTC)

DMacks (talk) 03:59, 26 January 2015 (UTC)