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6vfq7h
|
how much of the "side effects" medicine talks about are actually side effects?
|
In every TV ad, I've heard side effects ranging from headaches, abdominal pain, coughing, sneezing, sweating, heart attacks, stroke, arrhythmia, some disorder, cardiac arrest, etc.
But how much is actually proven to be a side effect? Are all effects experienced during clinical trials listed as "side effects" because companies are too cheap to do extra testing?
Does that mean that heart attack could actually be a 10% occurrence and not a .01%?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6vfq7h/eli5_how_much_of_the_side_effects_medicine_talks/
|
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" > But how much is actually proven to be a side effect? \n\nAll those are \"possible side effects\", meaning you *might* experience them. Drugs can be difficult to predict and just because someone experienced them in testing doesn't mean you will.\n\n > because companies are too cheap to do extra testing?\n\nExtra testing probably won't help. Suppose 5% of people who take the drug experience anal leakage while others don't. What will more testing reveal about that possible side effect?\n\n > Does that mean that heart attack could actually be a 10% occurrence and not a .01%?\n\nSuch a dangerous drug would never pass FDA approval."
]
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3fip1v
|
why when another person is picked up when they are conscious, they feel lighter than their actually weight, but if they are unconscious or like a rag doll they feel more like their true weight?
|
Just a thought going through my mind while at work...
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3fip1v/eli5_why_when_another_person_is_picked_up_when/
|
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"People who are concience are able to help you lift them, or shift their weight so it's less awkward to cary.",
"Think about it like trying to pick up a hundred pounds of sand. Consciousness is, metaphorically, sand bags. The contain the mass. A conscious person being carried has a desire to not be dropped, and so will assist the carrier by keeping his limbs tucked in, maybe even wrapping arms around the center mass of the carrier and alleviating pressure on the arms by putting more weight on the hips and legs. An unconscious person can't contain their body, their legs and arms will flop and they won't grab on for support, so it's like trying to lift a hundred pounds of sand using a large piece of tarp to carry it instead of a bag."
]
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[] |
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[],
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80bpn2
|
why does orange juice after brushing my teeth with mint tooth paste feel like the gods are punishing me?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/80bpn2/eli5_why_does_orange_juice_after_brushing_my/
|
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"Orange juice is very sour and very sweet. Your tooth paste temporarily makes you unable to taste sweetness. Without the sweet there to balance it, the sourness of orange juice becomes kinda overwhelming. \n[A similar thing happens with the miracle berry, which blocks sour and salty tastes](_URL_0_)",
"To add on to the other answers, as a general rule, you’re not supposed to brush 30 minutes to an hour before or after eating or drinking. Admittedly far easier said than done. Perhaps it’s the god of oral hygiene who’s punishing us all.",
"It’s the Sodium Lauryl Sulfate (SLS) in most toothpaste that causes this reaction. Find a toothpaste that is SLS-free and you can enjoy your orange juice without fear of punishment. "
]
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j3mnq
|
li5: cuban missle crisis, bay of pigs...
|
I wasn't around for these activities. Can someone help me become less herpderp about it?
What did the USA do, what did Cuba do, and how did it make everyone feel?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/j3mnq/li5_cuban_missle_crisis_bay_of_pigs/
|
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"Long ago, in 1823, President Monroe announced the Monroe Doctrine, which essentially said that the United States would view any attempts by European nations to colonize North American countries as threats to US national security. This is important.\n\n\nCuba used to be ruled by a US-friendly dictator named Fulgencio Batista. The US liked Batista, the communists in Cuba didn't like him. In 1959 there was a revolution in Cuba and the communists, led by Fidel Castro, took power. Now, the communists in the Soviet Union were generally big fans of any other nation becoming communist, so they immediately tried to become allies with Cuba. The United States was not happy about the Soviet Union getting an ally in their backyard, and remember the ancient Monroe Doctrine allowed them to say that the Soviet Union interfering in Cuba's affairs was a threat to the US. This made sufficiently flimsy justification for the US to attempt to remove Castro and reinstate Batista or another US-friendly ruler.\n\nIn 1961, Kennedy authorized the Bay of Pigs invasion. Essentially a bunch of exiled Cubans were trained by the CIA to invade Cuba. The plan hinged on the fact that the communist Cuban army would be weak, the Cuban resistance would want to lend their support to the exiles, and the Cuban people in general would be happy to help overthrow Castro. As you can guess, it backfired. The invasion failed in 3 days, and it was a big foreign policy disaster for Kennedy.\n\nThe Cuban Missile Crisis was basically the closest the world ever came to full-scale nuclear war. As I mentioned above, the USSR and Cuba were allies, and the USSR had started stockpiling missiles in Cuba that had the ability to strike most of the continental US. The US had a similar situation with their allies in Turkey allowing them to strike the USSR. In October, 1962, a US surveillance plane took photos of Soviet nuclear bases under construction in Cuba. This kicked off about two weeks of posturing and brinkmanship over the Cuban bases. Hawks in the US wanted Kennedy to invade Cuba, which would have essentially kicked off a nuclear war. Ultimately the crisis was settled by Kennedy and Khrushchev (then head of the USSR) agreeing to get rid of the bases in Turkey and Cuba."
]
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1m6g0q
|
how did cavemen maintain their teeth if they didn't have the proper knowledge and tools the same way we do in the modern world?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1m6g0q/eli5_how_did_cavemen_maintain_their_teeth_if_they/
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"They did not. Many died of starvation because they could not eat. ",
"Did did not have any added sugar in their food, which made it much easier to maintain good teeth health.",
"As far as I can tell, most people who survived childhood lived fairly long lives, 40 years at least to a high of 70. This is only well sourced since well into modern men since there are few bodies to make generalizations on of cavemen.\n\nIt seems a study published this year in *Nature Genetics* done by University of Adelaide is frequently referenced as saying that Cavemen had a better set of bacteria to protect their teeth and postulates our diet favors less helpful micro-organisms. _URL_0_\n\nThe true answer to this at the moment seems to be: we don't know if cavemen cleaned their teeth or not, we don't know how often they kept all their teeth until death, and we don't know how often they died of dental problems.",
"They probably didn't.\n\nBut between not having refined grains and sugars, and having to gnaw at their food a lot more, they probably avoided a lot of the dental problems that face modern humans.",
"Dentist here. Cavemen did not have modern diets and had no refined sugar. Eating mostly meat and raw foods, cavities were not a problem, just like they aren't for most animals. Cavemen probably didn't snack too much, as there was not an abundance of food or resources. No snacking and no sugar so, for the most part, cavities were not a problem for cavemen. However fossil records have indicated almost universal periodontal disease in prehistoric man. Basically meaning they were losing bone around teeth from an infection in their gums."
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1y7s84
|
Why did stars stop producing new elements?
|
As I understand it, Helium and Hydrogen were the original elements, and additional elements were formed when stars died out, which then laid the building blocks for more complex combinations and ultimately life as we know it today. My question is why aren't stars still producing new elements as they die?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1y7s84/why_did_stars_stop_producing_new_elements/
|
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"_URL_0_\n\nElements up to Iron are formed during the life of stars, heaver during supernovae star deaths. \n\nSo, stars *are* producing new elements as they die, if they're massive enough. \n\nStars that aren't massive enough to die as a supernova just use up all their fuel and become white dwarfs and eventually black dwarfs. The reason is that the fusion of iron atoms does not *produce* energy, it *consumes* energy. So, fusion past Iron doesn't release energy and everything just \"runs out of gas\" quite literally."
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[] |
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4mbrg3
|
how come most people who grew up poor/lower socioeconomic, usually stay that way?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4mbrg3/eli5how_come_most_people_who_grew_up_poorlower/
|
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"Two main reasons\n\nFewer opportunities. This sounds like a cop out, but it's true. It's harder for the lower classes to afford college, and many don't have the ability to finish highschool before they need to find a job to help cover bills. Of those that do go to college, not many can afford unpaid internships and therefore don't have the resume necessary to break into higher paying \"white collar\" jobs. This means that even those with degrees sometimes end up with blue collar jobs where their education is almost useless.\n\nPoor habits. Because many grow up living paycheck to paycheck, they get bad habits like spending excess money as soon as they get it instead of saving. They immediately try to upgrade their life by getting a better car or better apartment instead of saving their money and living frugally. This means that they don't usually end up with the money to be able to afford real improvements like buying a house.\n\nTLDR- It's a combinations of too few opportunities and too poor of habits.",
"Because their parents can not afford to put them through college therefore they were probably not pushed to go right away and just have that extra hurdle of trying to work and pay their way through an education. ",
"Poverty is known to be perpetual for one pretty huge reason; the available opportunities. \n\nIt is repeated time and time again, but basically those born economically struggling area, in a \"poor\" family, and such forth have less immediately available opportunities to succeed upwards compared to those of the upper 10% and more opportunities for failure downwards than those of the upper 10%. \n\n For example:\n A child growing up in a poverty-stricken lifestyle will most likely have easier access the drugs, gangs, and other influences. As well as less access to positive influences such as a good school, a supportive and educated family, great role models for advice, etc. \n\n Meanwhile, a child growing up in a well-off family will have access to better schools, educated individuals, and would most likely know no one in a gang. As for drugs, a well off child's parents will probably have the proper resources to help any problem, however, drugs will not too apparent in his environment to influence him. \n\nThat is merely just growing up. In adulthood, many of the same problems exist, however, more are tacked on. The key to success is having an education or marketable skill, those are usually tied. A poor working full time and barely making it will most likely face constant stress and anxiety around just surviving. He most likely will struggle to save enough to get an expensive education or won't have enough time to work on a skill. \n\nOn the other side, a very well-off person can afford to pay people to do his/her chores there for freeing up time to work on a skill, or they can have enough money to go get an expensive education. They are not stressed or living check to check, and there for can focus on further their education, bettering them. \n\nThe list can go on and on, but pretty much it comes down to opportunities. ",
"One underappreciated factor is that poorer individuals simply aren't as well connected as richer ones. You can take two students same in all traits except how they grew up. The rich student will have friends, family, etc, who can point him towards opportunities - say, a job vacancy that isn't even advertised, etcetera. The poor student will have to rely on publicly available information, which is usually... second-rate.\n\nWho you know and who your family knows matters. Unfortunately.",
"Some people do not stay that way. Immigrants can accumulate more wealth than native born residents of their country can become more affluent over twenty years. This is true all over the world.\n\nThey will work extra hard, not spend anything unnecessary. They will live in small cramped quarters. They will invest their savings wisely. It is an attitude they have. "
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1pja95
|
Is there anything special or discerning about "visible light" other then the fact that we can see it?
|
Is there anything special or discerning about visible light other then the sect that we can see it? Dose it have any special properties or is is just some random spot on the light spectrum that evolution choose? Is is really in the center of the light spectrum or is the light spectrum based off of it? Thanks.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1pja95/is_there_anything_special_or_discerning_about/
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"It's not amazingly special, but there are some good reasons why animals have similar ranges of vision (although some go a little bit into infrared and ultraviolet). I can't talk about evolutionary pressure because that's not my field, but I can talk about the physics of light and why if I was the engineer tasked with designing a biological eye, I would use visible light.\n\n1. While the Sun emits light at all sorts of wavelengths, the peak is in visible light - in green to be specific. So we get the brightest light at visible.\n\n2. The atmosphere is partially opaque at a lot of wavelengths. There are convenient \"windows\" where the atmosphere is transparent: at radio wavelengths and at visible wavelengths. So it's much easier to transmit and receive information over long distances using radio or visible light.\n\n3. Our eyes detect light with chemical reactions. So the light photons need to have a similar energy to the range of energies used in chemical reactions, and visible light has energies of around 1-10 eV, which is just right. It also means that this light is easily absorbed and reflected by objects we interact with, and that's what allows us to see things: things like gamma rays or radio waves aren't very well absorbed by things like people, trees, or computers, so it's very difficult to get a proper image of those types of object at these wavelengths.",
"Visible light is also kind of a transitional area between IR - transmitting a lot of heat - and UV - pushing into ionizing radiation.",
"I don't know a ton about the evolution of our eyes specifically. I can tell you, however, that the reason that the visible light is in the middle of the spectrum is because the wavelengths of these specific lights are the approximately the median for light wavelengths. That said, the amount of light out there that is not visible far exceeds the amount of visible light. If you are looking at a spectrum that does not indicate that by showing the visible light spectrum as a small section near the middle left of the spectrum, that might be misleading, but those are usually made to show the different colors of light involved in the visible spectrum, so it really only should be used to observe the qualitative differences between the spectra.\n\nAs far as I know, there is nothing inherently \"special\" about visible light, but I am only in the very early stages of an astrophysics degree, so that is my disclaimer there. I could very easily be wrong about that. ",
"Chemical bonds have similar energies to UV-vis light meaning it's easy to do chemistry to detect light, and the atmosphere is transparent to visible light so it's a good way to detect things. UV light is quite damaging to things and splits apart a lot of bonds so it's dangerous seeing that.\n\nTo my knowledge no organisms can directly sense IR light, presumably because they have no chemical bonds with a similar energy to be split by them. They have heat detecting channels which are warmed up by a variety of sorts of radiation, IR especially. Microwaves, radiowaves, gamma and xrays would also be very hard for a biological organism to detect.",
"Here is an article about the absorption of light in seawater:\n _URL_0_\n\nIt shows that visible light penetrates seawater much better than other parts of the spectrum. This means when eyes were first developing in our aquatic ancestors, it was much more beneficial for them to be sensitive to the 'visible' range of the spectrum.",
"Light with wavelength less than 400 nm (aka UV light) is especially harmful to our cells, especially sensitive ones on our retina. Our eyes are damaged by the sun just as our skin is, hence why sunglasses should be worn to protect your eyes from UV light (sounds reasonable, yet only 9% americans polled know this compared to over 75% of Australians due to their investment in preventative care instead of heath care). Our cornea and lens filter most UV light out before it reaches our photoreceptors. If large amounts of UV light was allowed to hit our photoreceptor cells that allow us to see, it would damage them thus blinding us and we would not be effective at reproduction. On the other side of visible light, long wavelength infrared light may be difficult for our eyes to localize because of the radiant heat from our body. Near wavelength infrared may be something of a buffer? Finally, the optical system defined by the shape and index of air/cornea/lens/eye is sensitive to wavelength (this is described by one of the more complex laws of linear optics I cannot recall its name). Having too large of a range of wavelengths could effect the quality of vision by creating chromatic aberrations on our retina. In my opinion, our brains could adapt to chromatc aberration although there is no proof that is has probably because it is not significant enough to affect our vision given the current visible spectrum. These are the primary reasons based on my knowledge but there are several researchers looking at these phenomenon (UV damage, IR radiation, chromatic aberration) so there is a ton of info about this stuff in journals. I wouldn't be surprised if there were more reasons, these are just what was on the top of my head. Finally, and this especially applies to short wavelength IR, our ability to see is governed by evolution of proteins that absorb certain wavelengths. The DNA coding those proteins not only have to spontaneously mutate into existence but they must give the animal a significant advantage over the rest of the gene pool before the mutation becomes the norm. over 10% of the human population gets along just fine carrying genes for color-blindness. Do we really need even more visible colors? What would be the evolutionary benefit? Source: I am an optometrist.",
"The easiest explanation is convenience. Visible light has sufficient energy to cause electronic transitions in chemicals(bumping an electron into a higher orbital), but not so much energy to cause damage like UV. Additionally the spectrum we are able to observe corresponds to the maximum intensity of the sun. The highest intensity light coming from the sun is in the yellow-green part of the spectrum which is dead center for our sensitivity as well.",
"There are a variety of reasons why, for humans, the visible spectrum is where it is.\n\n* Our visible spectrum is closely correlated with the spectrum emitted by the Sun. For the purposes of sunlight, the light emitted by the fusion reactions that fuel the sun are completely irrelevant - The Sun is basically just a giant black body emitting [black body radiation](_URL_2_) at it's characteristic temperature, which is ~5700 K. That puts it's peak at 500 nm, smack dab in the middle of our visible acuity (390-700 nm). Well, not precisely in the *exact* middle, but pretty close given [this spectral curve](_URL_0_).\n\nThe point is we're making use of the light that's available to us, sunlight.\n\nIt's also the most **useful** part of the spectrum. That is to say, there are good and proper reasons why it would be bad for us to try to use different parts of the spectrum. There are two cases:\n\n* As you get to wavelengths *shorter* than 390 nm, (higher frequencies,) the photons get more energetic. It's not that big of a deal for the UV frequencies, but once you get into X-Rays and Gamma rays, you're doing damage to organic compounds.\n\n* As you get to wavelengths *longer* than 700 nm, the resolution you're capable of generating degrades. That's because you cannot use a photon to resolve details smaller (or even of the same order of magnitude) than it's wavelength. That's the scale where the photon stops being *specularly reflected* by those details and starts being **diffracted** by them instead. As you go further the photon stops interacting with it at all. A Radio Wave (wavelength ~ > 1 m), for example, will just blow on by a person without being affected by them very much at all. That's one of the reasons we use radio waves for cell phones - So that your reception isn't ruined when someone steps between you and the cell tower.\n\nWhat does this mean for us? Well, in the far-infrared and microwave wavelengths, we wouldn't be able to resolve details. Not great for a species that was a predator/carnivore when it was evolving.\n\n* Finally, (and this is a bit of a corrolary to item #1) there are spectral bands that the atmosphere absorbs, meaning even though the sun's emitting them, we're not seeing them. The atmosphere's basically four compounds: Nitrogen, Oxygen, Water (vapor) and Carbon Dioxide. Nitrogen and Oxygen don't do much, but Ozone filters out quite a bit starting at around 3000 nm. Then water kicks in: Water vapor is opaque to microwaves around 7.5 mm. There's a vibrational mode in the water molecule: Imagine you making a peace sign with your index and middle fingers. Now imagine the oxygen is sitting at the junction between your two fingers and the two hydrogens are at your fingertips. The vibration of the molecule is you, pushing your fingers together and then apart, over and over. That vibrational mode starts to resonate at 40 GHz, which is the frequency corresponding to 7.5mm microwave wavelength, so it filters those wavelengths out.\n\nHere's a graph of the opacity of the earth's atmosphere by wavelength. Conveniently it shows where the visible spectrum is as well:\n\n_URL_1_\n\n**TL;DR**: The spectrum we see is visible because it's the spectrum we actually receive from the sun, and the other wavelengths aren't as useful anyway; They tend to be damaging to our health or useless at resolving detail.",
"It's not a random spot. We see the light in the 'visible spectrum' corresponds with the peak energy and brightness that gets through the atmosphere. Ever sense a competition of photosensitive cells started, selecting for sensitivity to where you get the most feedback in the atmosphere was a natural advancement.\n\nOther than that, outside of the atmosphere and water, there's nothing special about 'visible light' at all. It's just special to us on the surface. It's one reason I get irritated when people look at a picture from various telescope and get all excited, then get disappointed when they learn it's not 'natural color', like the contrast in a different band is somehow 'fake'. Requiring objects in space to fit our atmosphere's narrow band of permissible light in order to appreciate their wonder is amazingly short-sighted. (doh, pun)",
"Besides [Astrokiwi's excellent post](_URL_0_) \n\nI would add this [image](_URL_1_) . You can see the transmission window for water pretty much matches with visible wavelengths. \n\nWater, the original \"solvent\" in which life originated, is pretty absorbing outside of the visible. It is therefore not surprising that life, which so crucially depends on water, would not have bothered to be sensitive to other wavelengths. \n\nAs such, most animals with a [non-compound](_URL_2_) eye (and especially those with a lens and a cavity behind, like mammalian eyes) have demonstrably evolved it while being aquatic. They eye is filled with (mostly) water. So you will not find many such animals exhibiting any sensitivity outside the visible, since anyway, their eye is not well adapted to transmitting those wavelengths. \n\nAnimals with compound eyes have the photoreceptor near the surface of the eye and have therefore sometimes evolved sensitivity outside the visible once outside an aquatic environment (insects can be sensitive to UV for exemple). ",
"Essentially, visible light is the portion of the spectrum with the greatest amount of energy you can hit most molecules with before they break (ionize) but still cause a biologically detectable change.\n\nIt all comes down to chemistry... light in this region of the spectrum does not follow different laws of physics as compared to light in other parts of the spectrum. However, our (and matter in general) ability to interact with light in different parts of the spectrum varies widely (or wildly, depending on how excited you get about science). For example, we have sources (eg. LED's, lasers, and lamps) and detectors (eg. photodiodes, bolometers, antennas) for various wavelengths in the gamma ray, x-ray, UV, visible, near-infrared, infrared, terahertz, microwave, and radio. There are portions of the spectrum that are quite difficult to interact with, such as gamma rays, hard x-rays, and terahertz radiation.\n\nThe blue end of the visible spectrum pretty much ends where the energy of a single photon is enough to start kicking electrons off molecules. That means a biological system gets damaged by higher energy photons which would be past the blue end of the visible spectrum.\n\nThe red end of the spectrum is where individual photons stop being able to excite electronic transitions in most molecules- that means where the photons don't have enough energy to bounce electrons between individual molecular orbitals. If they can't move electrons between orbitals, then they can't change the shape of the molecule, so it's hard a biological system to detect the light past the red end of the visible spectrum. Infrared and lower energy light mostly interacts with vibrational, rotational, and phonon modes of matter, all of which correspond to lower energy levels.\n\nThe spectrum of light doesn't really have a 'center'. The energy level (and wavelengths) of visible light are sandwiched between shorter and longer wavelengths, but there is no center... much like if I were to ask you to define the middle of the numeric range from zero to infinity. [Here is a picture of the spectrum](_URL_0_), and visible light is typically shown in the center by using a very non-linear scale.\n\n"
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7gwaqu
|
The golden age of Islam saw the middle east as one , if not the centre of scientific progress during it's time. What happened that today the west overtook the islamic world in scientific progress and innovation?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7gwaqu/the_golden_age_of_islam_saw_the_middle_east_as/
|
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"https://www.reddit.com/r/AskHistorians/comments/1pzf28/why_did_european_powers_in_particular_start/cd7n7j1/?context=3"
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||
150ogm
|
When a fighter jet fires it's machine guns, does it slow down the jet by a considerable amount?
|
Mostly self-explanatory... Also, is there a top speed where it is dangerous to fire a fighter jets machine guns?
|
askscience
|
http://www.reddit.com/r/askscience/comments/150ogm/when_a_fighter_jet_fires_its_machine_guns_does_it/
|
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"Not considerably, it's all just conservation of momentum.\n\nxkcd's What If [handled a similar question](_URL_0_) about machine gun jetpacks. A quote of interest about the Gryazev-Shipunov GSh-6-30, a minigun sometimes mounted to Russian aircraft:\n\n > [T]he recoil … still had a tendency to inflict damage on the aircraft. The rate of fire was reduced to 4,000 rounds a minute but it didn't help much. Landing lights almost always broke after firing … Firing more than about 30 rounds in a burst was asking for trouble from overheating …\n\nSo particularly heavy duty guns can have negative effects on aircraft.",
"Other answers are generally correct, explaining that the effects are mostly negligible.\n\nHowever, there is one airplane that stands head and shoulders above other aircraft in terms of amount of gunfire that it can rain down upon a target: the A-10 Thunderbolt II (aka Warthog).\n\nThe A-10 has a 30 mm gatling cannon under the cockpit, capable of firing over 4,000 rounds per minute. On the A-10, the firing rate is set to 3,900 rounds per minute. Many rounds can be used, but a favorite is the .69-kg (1.5 lb) depleted uranium ammo. Muzzle velocities are around 1070 m/s (.66 mi/s).\n\nSo when the above rounds are fired at the specified rate and velocity, they produce about 48 kN force. This is over half of the force generated by the two GE turbofans in back (40 kN each).\n\nTo compensate, pilots would dive when firing (diving is also helpful at hitting targets on the ground).\n\nAdditionally, yes, I know there are sites that say this is a myth, but no, it's not. Do the math. The recoil of the gun is greater than the force generated by one engine.",
"This isn't a jet but the B-25 had a 75mm gun on it's front and caused the plane to slow down. [wikipedia](_URL_0_)"
]
}
|
[] |
[] |
[
[
"http://what-if.xkcd.com/21/"
],
[],
[
"http://en.wikipedia.org/wiki/North_American_B-25_Mitchell#Operators"
]
] |
|
2dqwa1
|
What mechanisms support genetic diversity of the whole population of (complex) species?
|
It is well-known, that incest is disastrous to (human) population health. It is because, as I know, due to "matching" of mistakes in chromosomes (that happen during copy-paste of chromosomes). Also, as I know, non-negative mistakes literally do not happen (in humans). Thus, we, people, are in a big bowl of bad matching genetic mistakes... if there is no source of incoming (good) genetic diversity. So - what are they?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2dqwa1/what_mechanisms_support_genetic_diversity_of_the/
|
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"Most mutations are indeed deleterious/bad, but there are also beneficial/good mutations. A good example is the ability to metabolize lactose as adults - since we've domesticated cows/goats/etc. and milk is a good source of nutrition, there is positive selection on this trait being maintained on a population. That's why this mutation, or trait, is very common among European and African populations.\n\nIt's helpful to think of selection as a \"force\" that pushes a trait to become more or less common in a population. If selection against a trait is strong enough, it will die out (go to 0% incidence in a population), and if it is strong enough, it will \"fix\" (go to 100%).\n\nIn addition to selection, there is genetic \"drift.\" Because of how people pair off to mate and how traits get passed on, there is a degree of randomness that causes the percentage incidence of a trait in a population to fluctuate - like a random walk in physics.\n\nJust from these factors alone, with the introduction of new traits (mostly bad, but some good), there is always going to be diversity within a population. But because we have two copies of each chromosome and each gene, one from mom and one from dad, you can also have interesting situations where having one mutation has a very different outcome than none or two. In some of these cases, you can get a stable percentage of a trait in a population at a value between 0% and 100%. A good example is the mutation that causes sickle cell anemia if you have two copies, but may protect against malaria if you have one copy. \n\nIf you want to learn more, Population Genetics by Gillespe is an accessible (and cheap) book on this subject. I think a little bit of calculus helps for the math. \n\n_URL_0_",
"You are using some odd terminology that I think may be confusing you a bit. Calling mutations 'mistakes', while true in one sense, is inaccurate nonetheless. Mutations are the ultimate source of genetic material, 'good' and 'bad'. Also, you are jumbling up the source of genes at the molecular level with the frequency of alleles within a population.\n\nHere's a quick rundown:\n\nInbreeding depression occurs because it increases the likelihood of children being born homozygous (having the same version from both parents) for potentially deleterious recessive alleles. In a large population with little or no inbreeding, these alleles can persist because if they are relatively uncommon, there will be heterozygotes (individuals with two different alleles at a given locus) who are not impacted, or don't have the disease. They can keep passing on the allele, even though all homozygous recessive individuals may die before reproducing. So if a small related subset of the population that contains the recessive allele inbreeds, there is a higher than otherwise normal likelihood they will produce children with the disease.\n\nThis is a separate issue from where those versions of the gene originally came from. Those are the \"mistakes\" you reference. Those mutations, while they can often produce a version of a gene that does not code properly for a necessary protein and therefore is deleterious, also gave rise to all your other genes. As an easy to follow example, sometimes entire genes mistakenly get copied an extra time. (I should note this is within one line, it's completely unrelated to different alleles you receive from your parents, as in the above discussion). The extra gene does nothing and is not selected against. It can now mutate further, unrestricted, and over time come to code for an entirely new beneficial trait never before seen in the species.\n\nSo basically, non-negative mistakes DO happen, inbreeding decreases genetic diversity but has nothing to do with this level of biological organization, and mutations are the ultimate source of genetic diversity, while it is potentially maintained and/or increased by mating patterns and immigration into the population."
]
}
|
[] |
[] |
[
[
"http://www.amazon.com/Population-Genetics-A-Concise-Guide/dp/0801880092/ref=sr_1_1?ie=UTF8&qid=1408234938&sr=8-1&keywords=population+genetics"
],
[]
] |
|
wlhve
|
Could a Middle English speaker and a Modern English speaker have been able to verbally communicate
|
Given the changes the English language has made over the last few centuries, especially the "Great Vowel Shift," would a hypothetical time traveler that spoke modern English been able to carry on a conversation with someone in 13th century London?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/wlhve/could_a_middle_english_speaker_and_a_modern/
|
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"This is not really a historical question and r/linguistics could probably answer this better. My take on it:\n\nIt would be difficult, but you could probably communicate.\n\nHave a look at Middle English yourself to find out. For example [here](_URL_0_).",
"I think it would be fairly difficult but not impossible. The main problem, as you point out, lies in the Great Vowel Shift which began around the fifteenth century, and changed the way all of our long vowels sounded. Then there are also numerous words which have either been added to English, dropped out, or changed the meaning. Grammar is somewhat different, mostly in syntax, but not enough to really stand in the way. So if things were kept simple, I do think you could make yourself understood, especially with a little practice (unless your time-traveler is in a hurry). Go back a few more centuries and the answer would be no.",
"Eddie Izzard once tried an experiment similar to this. See _URL_0_",
"A bit easier if you both wrote rather than spoke and of course you'd have to stick to topics for which there was Middle English vocabulary. To get an idea of what's involved you can try reading the [Middle English version of the Canterbury Tales](_URL_0_) and [listening to a reading of it](_URL_1_) and see what makes more sense to you."
]
}
|
[] |
[] |
[
[
"http://ebooks.adelaide.edu.au/c/chaucer/canterbury/burrell/chapter1.html"
],
[],
[
"http://www.youtube.com/watch?v=OeC1yAaWG34&feature=youtube_gdata_player"
],
[
"http://www.fordham.edu/halsall/source/CT-prolog-para.html",
"http://youtu.be/QE0MtENfOMU"
]
] |
|
49iy49
|
historically, does socialism work long-term? why or why not?
|
Citing historical examples, not hypothetical, does a socialistic system of government really work in practice over the long term?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/49iy49/eli5_historically_does_socialism_work_longterm/
|
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" Nearly every socialist country has given it up after experiencing a string of economic failures. The most notable example is the Soviet Union. Another interesting example is China, which still calls itself communist but is in fact a large percentage capitalist. Both of these countries experienced not only poverty, but even starvation of millions of people, as a result of their failed economic policies during socialism.",
"Pretty much every democratic country that collects taxes and uses tax money to fund things like infrastructure, healthcare, public education, etc is socializing the costs of all of those things, so I would argue that some socialist principles work out pretty good in the long run.",
"There has never been a long-term socialist government. I highly doubt there has ever been a short-term socialist government on any real scale. (As in, more than a few hundred people.) Plenty of governments have attempted to be socialist, but none have accomplished it. \n\nThe fundamental core of socialism is the obliteration of the concept of value, both of people and material items. Which goes against basic tenets of rationality, (at least, for the long foreseeable future.) This manifests in various contradictions and hypocrisies which prevent a society from properly functioning.",
"Social policies mixed with capitalism have been proven to work very well together. This includes the United States, Canada, and many European countries. Pure socialism (public ownership of *all* means of production) has never been properly implemented.\n\nCapitalism comes with many inherent flaws, and a \"mixed\" approach which applies social control over some aspects of the economy seeks to remedy those flaws.",
"This ends up not being a topic that lends itself well to an ELI5 explanation.\n\nThe reason for this is that we're discussing a political entity who who has at its core a tactic of controlling the definitions and names for things through propaganda.\n\nOne of the better examples is the Bolshevik party in Russia (originating in 1905, coming to power as part of the 'October' revolution)... they eventually formally became the party of Vladimir Lenin. At the time, they called themselves officially the Marxist Russian Social Democratic Labor Party. But that's long and hard to remember so they called themselves the 'Bolsheviks'. Bolshevik in Russian literally means ' of majority'. Note that they called themselves this before coming into power, long before they would have been considered a majority party. Also note that their opposition party (Menshiviks) literally translates to 'of minority'. Even though, at the time, they were actually the majority.\n\nIt's a propaganda tactic, used in amazing effectiveness. Quite an interesting history study actually. They basically called themselves the majority and the masses started thinking of them in that light.\n\nRelevant Point: discussions on the topic you're asking about is steeped in a history of propaganda. You'll be lucky if anyone even agrees on what the difference between \"socialist\" vs. \"communist\" is.\n\nHow do I know all this? Well I speak Russian. I am not Russian, but have read many, many books on this history. It's fascinating.",
"There has probably never been a proper implementation of socialism on a large scale. Certainly all of the historical examples, like the Soviet Union, are not examples of socialism. In all of these traditional historical examples, the government wasn't actually socialist, or it sacrificed its socialism pretty quickly for something else, like fascism, but continued to call itself socialism, confusing the world to this day.\n\nSo we really don't have good information to say whether or not socialism can work long term. Someone needs to really try it for real."
]
}
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[] |
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[],
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1g1b3l
|
what are the main differences between sunni and shia islam?
|
There seems to be a lot going on between these groups and a lot of violence and hate towards each other. Why is this happening? Can this be viewed like the Eastern Orthodox and Roman Catholic Church?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1g1b3l/what_are_the_main_differences_between_sunni_and/
|
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"Orthodox vs Roman Catholic is kind of a workable example to a point, but it misses the huge political factor.\n\nTo delve into it a bit more, you need to know why they're different. Islam follows on from Judaism and Christianity with a fellow named Muhammad, who around 600AD, proclaimed that he was receiving revelations from God and that he was the next great prophet (Christ being the last one). He gathered followers, eventually raised an army, and conquered the crap out of the Middle East, giving conquered people options between converting to this new religion of Islam, paying tax, or dying (some debate on this in posts below). Then he chilled out for a bit and eventually died.\n\nNow, let's get to the point differences:\n\n1: A large part of Islam has been based around those who knew Muhammad but weren't recorded in the Quran, and what they claim Muhammad said, meant, or did off the record. Called Hadiths, these are Islamic laws or suggestions based around such anecdotes. It could be as simple as a man who once observed Muhammad treat a beggar in a certain way declaring that this way of treating beggars is the one true way all Islam should follow, through to rather complicated arguments of how to interpret Islamic law written in the Quran based on what was implied by something Muhammad was once recorded to have said. Sunni and Shia Muslims believe in and accept different Hadiths, as do various smaller branches within those two factions.\n\n2: The more concrete divide is the matter of a chap named Ali, and the matter of who would succeed Muhammad upon his death. Ali was Muhammad's first cousin and closest living male relative, and also married Muhammad's daughter. Shia Islam believes and accepts that Ali was the rightful heir to Muhammad, stating that only God has the right to choose such leaders, and had appointed Ali caliph and all round #1 guy in Muhammad's wake. The Sunni, by contrast, whilst holding him in high regard still consider him one of FOUR caliphs, rather than the one and only. It's a bit more complex than that, but it'd be stepping out of ELI5 territory and into a major debate (Llama Labia made a post below that does go into those details a bit more. Scroll down and go look!). At the time, there were battles over this.\n\n3: Sunnism puts a LOT of emphasis on Sharia, Islamic law. Shia aren't as strict about taking law solely from the Quran, and have several other ways of defining Sharia law (such as Mantiq, which is argument of traditional logic, or proclaiming a change to the law to be in 'public interest'), for better or for worse.\n\n4: Different beliefs on what will happen at the end of the world. Both believe some kind of redeeming figure will appear as prophecised, but its nature and actions are disputed by both sides. The Sunni view him kind of as another of God's prophets who will arrive to rule the world and re-establish Islamic rule and law. The Shia view is more akin to a Biblical rapture, with a great host of badasses showing up to kick the hell out of everything bad and wicked and wrong.\n\nClarification by SuitedPair below: \"Sunnis also believe in Jesus and the Mahdi returning for the end of days to fight off Dajjal(the antichrist)\"\n\nDouble-clarification by LlamaLabia below, go read a big long post!\n\n5: Lots of different practices. Praying is done slightly different between branches, how much of a woman should be covered by hijab is debated between branches, those kind of things.\n\nSo now we know where they came from and how they differ.\n\nWhy they commit acts of violence and hatred against one another? That's where it all gets very political. Traditionally, Sunni has been the more dominant, anti-revolutionary branch, and in the last 30 years this has been challenged. Shia has been on the rise, foreign interests such as America have gotten involved, the Gulf War and the War on Terror have all contributed. Most of these attacks are explicitly Sunni attempting to supress Shia uprising, or Shia attempting to destabilize Sunni rule.\n\nIraq and Pakistan are the most notable. Much of it stems from the balance of power shifting away from Sunni towards Shia. Sunni proclaim Shia to be rebels, troublemakers attempting to start a civil war. Shia proclaim Sunni to be an unpopular, corrupt dictatorship and lackey of the American government. Iran is a bee in everyone's bonnet as it's the only country (edit: see TheWierdSide below) with a huge majority Shia population (around 90% Shia, most Muslim countries are closer to 80-90% Sunni) which makes Sunnis grumble and point at it as a bad example of what Shia rule is like. People don't like losing power and influence, ostensibly because it stops them being able to enforce their version of Islam in the form of Sharia law, banning of western influence, etc.\n\nExtremists constantly wade into the mix to do whatever they can for a personal power grab. Accusing the opposition of Zionism and collaborating with western forces is a great way to gain support and discredit political opponents, which is largely rooted in Sunni vs Shia political parties. The Taliban for instance explicitly supported anti-Shia groups in Pakistan in order for Sunnis to give political support in return, helping escalate the violence in the region.\n\nHell, some Al-Qaeda have called for all Shia to be treated as heretics and put to death.\n\nAll in all, it's a bit of a mess. The differences between the groups are in the minutae of religious texts. The violence between the groups really stems more from pure politics of who is in control.\n\nEdited to add: Check out the [ELI5 about Syria](_URL_0_) for a good breakdown of such a conflict playing out in detail right now. Though it's between Sunni and a tinier minority called the Alawites rather than Shia.\n\nAlso edited to add: I'm not a muslim myself, just have a friend who converted a few years back, and I made a great effort to understand. Also generally fascinated by theology but no formal education in it. So feel free to correct the hell out of my layman's understanding. Double edit: People have! Read the rest of this thread, there are a few practicing muslims correcting me or adding to what I wrote in more detail if you want that.\n\nFinal edit: Read the fucking sidebar. ELI5 has not literally meant \"something a five year old can understand\" for a longass time.\n\nDouble-final edit: Thanks for gold! Between that and a couple of PMs saying I've genuinely opened some eyes and educated people, this discussion has made me feel warm and fuzzy inside.",
"My knowledge of this is a bit rusty, but I'll have a go.\n\nIn the most basic, ELI5 sense: the main thing that separates Sunnis from Shias is that Shia Muslims believe the heir to the prophet Muhammed should be related to him by blood, and Sunnis do not. A man called Ali, who was Muhammed's cousin, is regarded as the first Shia Imam (Islamic leader / scholar). Shias believed he should be the one to succeed Muhammed as the first caliph (Leader of the Islamic state), while the Sunnis voted for, and eventually elected, a man called Abu Bakr. He was soon succeeded by Umar ibn Al-Khattāb, a close companion of the prophet. Sunnis generally view Umar as a strong and just leader, while many Shias see him as a traitor and usurper.\n\nIt's also important to remember that there are many different sects of Sunni and Shia Islam, who all believe slightly different things, but the roots of the separation between the two all stem from the disagreement over who would lead the Muslims after Muhammed, and all the events that occurred because of this.",
"I can go into the details if you want about the actual differences between Shia and Sunni.\nHowever, to help you direct your thoughts in the right direction, you should know that there is little to no violence or hate between the actual Sunni and Shia Muslims.\nWhatever violence we see and hear of is brought forward by extremist groups that use the religion to serve their own purposes.\nThey have extreme, violent, and sectarian views that call for violence and annihilation of the other group, and they have followers who are usually simple-minded people who are easily convinced and forget to use their reason to identify and stay away from this extremism.\n",
"Muslim dude here, will try to keep a simple explanation.\n\nProphet Muhammad is the main prophet (the last prophet) according to the Quran, which is the word of Allah (God).\n\nAfter the Prophet's death there were 4 main caliphs, all people who the Prophet had known. \n\nSunni people believe all these caliphs to be equal, while Shia people believe that since Hazrat Ali was related to the Prophet he was the rightful heir and caliphate. \n\nThe divergence started from there and then became a bit.. strange. So now you have Sunni people and a lot of sunni sects, and Shia people now do [matam](_URL_0_) (Note: Violent). Note, the pics are mostly of violent matam, most people just do it lightly with their hands but you can see the swords and knife stuff happening on streets here in Pakistan on relevant days.\n\nBecause this is historical talk, people have different interpretations and knowledge about the history and both Sunni and Shia people disagree with many things which happened. \n",
"To put it simply, one group believes direct descendants of muhammad are the most holy and should be the Islamic Leaders. The other group thinks the man \"closest\" to god should be leader, this caused a big dispute about 1500 years ago.",
"I spent a year teaching in Saudi Arabia. It was the Shia who worked and were more open minded. I don't know if that's because they're the minority or if it was cultural. ",
"Shi'ites believe the new Muslim leader should be a descendant of Muhammed (Which is difficult because it has to be male, and Muhammed only had a daughter; son in law was newest leader after Muhammad's death). \n\n\n\nSunnis believe they should elect their new leader. ",
"When the old boss died, there was a disagreement over who should be the new boss. Each of the two contender said they were the one true descendant of the boss and they should be telling others what to think and do.\n\nThey never resolved their disagreement so there has been those two lines of descendants ever since",
"They disagreed about who should rule a long time ago.",
"Muslim here. Lot's of answers. Some great, some okay, some poor. No one really gave the ELI5 answer. So here is my attempt:\n\nAfter Prophet Muhammad died, Abu Bakr became the leader of the Muslims. After Abu Bakr, then came Umar ibn al Khattab. After him was Uthman ibn Affan. Then it was Ali.\n\nThe Sunnis accept all 4 leaders while the Shia only accept Ali. They believed Ali should have been the leader of the Muslims after the death of Prophet Muhammad."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/explainlikeimfive/comments/1fz36z/eli5why_do_people_online_support_assad/"
],
[],
[],
[
"https://www.google.com.pk/search?q=matam&tbm=isch&tbo=u&source=univ&sa=X&ei=asm1Ud3tFcbC7AaI2ICICQ&ved=0CDQQsAQ&biw=1024&bih=667"
],
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[],
[],
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|
5m6er7
|
How popular was the name Muhammad before the prophet Muhammad was born?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5m6er7/how_popular_was_the_name_muhammad_before_the/
|
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"I spent around an hour looking but couldn't find too much. There is an article from 1936 (so methodologies have definitely changed since then) by Edward Jabra Jurji that claims that the name Muhammad has been in use in Arabia since the first-millennium B.C.E. \n\nJurji cites *Kitāb al-Ishtiqāq* written by Ibn Durayd (~10th century C.E) that the name Muhammad had been used prior to the birth of the prophet Muhammad in ~570C.E. However, it wasn't a customary name of the Quraysh tribe themselves. Muhammad's grandfather allegedly named him Muhammad so that he would \"be praised in the heavens and the earth\" (the name Muhammad is derived from the Arabic root ḥ-m-d meaning *to praise* and can literally be seen as the passive participle meaning \"the one that is praised\").\n\nJust to be safe, I checked the Arabic of *Kitāb al-Ishtiqāq* and found the quote attributed to Muhammad's grandfather as well as a list of others who had been named Muhammad before the Prophet himself.\n\nJujri also said that the name Muhammad had been found in Southern Arabian inscriptions and cited the *Corpus Inscriptionum Semiticarum* (The Collection of Semitic Inscriptions). However, when I tried to find the references inside of it I could not locate them (Volume 2, Tome 1, #353 and Tome 2, #420). This is probably due to my own inexperience with the Corpus though.\n\nSo at least according to Jujri and Ibn Durayd, the name Muhammad had indeed at least *existed* before the prophet was born. However, at least among the Quraysh it does not appear to be very popular. This can be backed up by the fact that in lists of early notable *Ṣaḥāba* (companions of the prophet) there are only [1 or 2](_URL_1_) other Muhammads found. However, after a few generations we can find [137](_URL_0_) with the name Muhammad. As you can see on the second list, a lot of them are \"Muhammad ibn xxx al-Ansari\" meaning that they were the sons of the residents of Medina who converted to Islam when Muhammad made it his home after fleeing Mecca. Thus, much of the popularity of the name can be attributed to the prominence of the Prophet, and not necessarily that it was a popular name before.\n\n\n**Sources:**\n\nJurji, E. J. (1936), PRE-ISLAMIC USE OF THE NAME MUHAMMAD. The Muslim World, 26: 389–391. doi:10.1111/j.1478-1913.1936.tb00898.x\n\nIbn Durayd, Abu Bakr Muhammad, *kitāb al-ashtiqāq*.\n\n"
]
}
|
[] |
[] |
[
[
"http://sahabanames.com/sahabi-names-for-boys/page/47/",
"https://www.wikiwand.com/en/List_of_Sahabah#/References"
]
] |
||
2wl98d
|
how people get graffiti in ridiculous places
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2wl98d/eli5_how_people_get_graffiti_in_ridiculous_places/
|
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"However they have to. Ladders, are common, as is standing on your friend's shoulders. They climb, jump, or hang as necessary. Some even bring rope and rappel down to where they need to get.\n\nIf you have Netflix, the documentary \"DamNation\" has a scene where protesters painted a dotted line and scissors on a dam they wanted removed. You can watch them do it, and it's one of the biggest and most ridiculous places I can think of. \n\nHanging from a rope with a bucket of paint. That's all there is too it.",
"Filmed with a potato, but my stomach still gets queasy watching [this] (_URL_0_)",
"There is a guy here in New Orleans that goes by the name \"Pyro Lies\" and he gets into some ridiculously crazy spots. I've always wondered how he pulls it off as well. One of his more recent ones is on a 24/7 lighted billboard above Superior Seafood, which is a super popular restaurant located on St. Charles Ave, easily the busiest and most iconicly famous street in Nola, other than Bourbon St. There are constant police patrols in the area, I have no clue how he did that one without getting caught. It's giganticly artistic, not just a scribbled name, and basically covers the entire billboard. It had to have taken a pretty long time to do. Shit is nuts. "
]
}
|
[] |
[] |
[
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||
3baqq8
|
What is the history of the Western Sahara? Why does Morocco have (no) legitimate sovereignty over this region?
|
If so why? In other words what determines territorial sovereignty? Maps show the Sahara under Moroccan control since at least Medieval Times under the Almohad and Almoravid dynasties (although it is ironically more the other way around as these powerful dynasties originated from the south). I know this isn't a popular subject but I hope someone would at least be able to answer what determines legitimate sovereignty.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3baqq8/what_is_the_history_of_the_western_sahara_why/
|
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"text": [
"/u/rkwan (partially) answers your question in [this comment](_URL_0_) to a similar question from 2 years ago.",
"A good resource is the non-binding ICJ advisory opinion issued in 1975. _URL_1_\n\nIt essentially holds that there was some contact between certain nomadic Saharawi tribes and Morocco, but not enough to establish sovereignty or have them be considered subjects of the crown. That said, advocates for Morocco either decry the advisory opinion or interpret that limited contact as proof (despite the fact the opinion says otherwise).\n\nAnother landmark document in the conflict is the Madrid Accords, when Spain was in a hurry to give up the territory. _URL_0_"
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/AskHistorians/comments/1de1g8/what_is_the_story_behind_the_green_march_and_the/c9sh8bm"
],
[
"https://en.m.wikipedia.org/wiki/Madrid_Accords",
"http://www.icj-cij.org/docket/files/61/6197.pdf"
]
] |
|
8wxgfx
|
Is it possible to detonate a thermonuclear device without a fission primer?
|
From my limited understanding of how Hydrogen bombs work, causing Tritium to fuse requires massive energy input really only available on the scale of fission bombs. Theoretically, could the same objective be achieved using something like lasers or a chemical reaction? Obviously any real answers to this are likely classified, but I thought I'd ask!
|
askscience
|
https://www.reddit.com/r/askscience/comments/8wxgfx/is_it_possible_to_detonate_a_thermonuclear_device/
|
{
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"text": [
"Yes. Most current fusion experiments use lasers, no they would not work for a weapon systems. It would be possible to use lasers to detonate a thermonuclear device, but it would be a very big system using lots of power. The energy has to come from somewhere. Fission is nice because it is the most energetic reaction we can produce, it is very high efficiency and puts lasers to shame in terms of pressure and heat. Where you'd need a whole modern physics lab to just get sustained fusion, a small, footlocker sized device with a shaped charge around some fissile material around fusion material would be all it takes, with a control system to kick off the charges right, to achieve thermonuclear fusion.\n\nExtreme magnetic fields can also sustain nuclear fusion, but again, it would be a huge amount of energy to push this anywhere near explosive amounts of energy. So much so that you'd probably need a fission reactor generating electricity to power the magnets (or lasers) thereby effectively just moving the fission out of the simple device and into the complex powerplant.\n\nThere are no chemical ways of generating the incredible amounts of energy required to fuse a meaningful amount of hydrogen rapidly enough to have it all fuse at once, rather than slowly.\n\nFusion's trouble is that as it occurs, it heats things up, and makes it harder for further fusion to occur in a sample, so you need more pressure and energy, which just makes it harder and harder. Achieving sustained positive delta energy fusion has been a subject of international research since, like, the 70s. It would be an incredible tool for generating electricity.\n\nI suppose if something was to work. It could be gravity, if you were to. Make something massive enough that the pressure of the fusion material on itself was enough to fuse, you'd be able to sustain it, maybe even explosively, but then the issue is if it is massive enough to do this how is it transported and aren't we just talking about stars at this point.\n\nThere's no conceivable way to sustain fusion without fission for the purpose of weapons, if it was possible we'd have it in power plants. ",
"The idea of using lasers to initiate fusion reactions was explored at length in the 1970s and 1980s. The problem is that the amount of power you need is still huge, so you need [a laser the size of a football field](_URL_0_) to try to ignite a reaction in a pea-sized amount of thermonuclear fuel. So in terms of using that in a weaponized way: it appears not. \n\nChemical explosives do not provide the necessary compression to ignite significant numbers of fusion reactions. \n\nAs for classification, the Department of Energy [declassified the following statement in 1998](_URL_1_):\n\n > Information on the DOE's pure fusion program:\n\n > (1)\tFact that the DOE made a substantial investment in the past to develop a pure fusion weapon\n\n > (2)\tThat the U.S. does not have and is not developing a pure fusion weapon; and\n\n > (3)\tThat no credible design for a pure fusion weapon resulted from the DOE investment. \n\nIf one had other highly-compact energy sources, like anti-matter weapons, you could imagine using them as a \"primary\" for a thermonuclear weapon. However our ability to collect/use anti-matter is currently pretty primitive. [There is a nice discussion of potential anti-matter thermonuclear weapons here](_URL_2_). Suffice to say this is filed under \"things we don't have to worry about for awhile (and if we have to worry about anti-matter weapons we already have issues separate from thermonuclear weapons to worry about).\" But it is probably the most \"plausible\" way to have a pure fusion weapon currently on the table."
]
}
|
[] |
[] |
[
[],
[
"https://en.wikipedia.org/wiki/National_Ignition_Facility",
"https://fas.org/sgp/othergov/doe/rdd-7.html",
"https://arxiv.org/pdf/physics/0510071.pdf"
]
] |
|
fdxmui
|
why do cribs get recalled all the time?
|
How hard is it to make a safe bed for a baby? Why do manufacturers not know how to do this by now??
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/fdxmui/eli5_why_do_cribs_get_recalled_all_the_time/
|
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"Usually because the dimensions between parts (a rail and a mattress for example) can, in rare instances, cause an infant to get caught or suffocate. Decades ago, there were many recalls because of really dangerous designs like latches that are easily opened or will allow a rail to fall on a baby or pinch their fingers.",
"It's easy to make a safe crib. Take hard, dense wood, shape it to fit snuggly, and use high quality fasteners.\n\nThe problem is that this is expensive. Given the choice, most people will buy the cheaper option if the product performs the same function. To chase sales, companies have to find ways to make things cheaper.\n\nSo companies try to reduce the cost of their products with cheaper materials and labor so they are barely functional. This generates the most profit (cheaper = more people buy it over expensive options and they make more money per sold piece). Often times, this sacrifices safety because they didn't need to test for it (no regulations) or they didn't want to test for it due to cost. For more unscrupulous companies, recalls cost less than the lost profit if they didn't make the product.",
"In many cases, the issue was convenience vs safety.\n\nMost cribs have an adjustable mattress height. For tiny infants that barely move, you can keep the mattress high so it's easy to reach them. But when they get to around 9 months and they can pull up and try to crawl over the side, you have to lower the mattress.\n\nThe problem is, in order to lower the mattress enough that the baby can't escape, it's now so low that many adults can't easily reach the baby - especially if the baby is squirming and doesn't want to come out of the crib.\n\nOne solution was the drop-side crib - one of the sides could slide down to make it easy to reach the baby. Unfortunately it was extremely hard to build a mechanism like that and also make it 100% foolproof. [_URL_0_](_URL_0_)\n\nThat wasn't the only solution. Dozens of other types of cribs had mechanisms to make things more convenient for parents that compromised safety.",
"Also, some defects only become apparent after years of wear and tear, but would still result in liability to the company. New safety standards might also force the recall of certain older models.",
"I've often joked that they are making newer model babies that aren't compatible with the old models. The same thing about cribs can be said about car seats (they even have a six year expiration date stamped on them now).\n\nI wish I knew the answer too. Who wants to chance anything and put their baby at risk?",
"Former news producer here. One issue is you likely just hear about cribs getting recalled a lot more often than the thousands of other products that get recalled all the time. The only time we put recalls in our newscast is if it was particularly spooky, things involving food, babies and medicine are top of the list. \n\nNew mothers get scared about anything that could harm their baby, share it all over Facebook, then you hear about it.",
"For everybody saying that making a safe crib costs money, that's not really the case.\n\nMaking a crib that is suitable for safe sleep for infants is actually incredibly easy and cheap to do. All it's all the extra shit costs money, and presents issues. Infants need a flat surface, with a semi-firm mattress, and some walls. It needs to not easily tip over. That's literally it. It's all the extra options that present issues, like trying to make it convert into a toddler bed, have a mobile hanging from it, drop down sides, etc. Those things can present safety issues. These companies spend lots of time on these things, because it appeals to parents. Having these features makes parents feel like they are getting the \"best\" for their baby. But it's really just added cost and possibly even less safe.\n\nA thin mattress in a cardboard box is likely as safe as most popular cribs. Many babies in Finland sleep in government issued boxes, and they don't have problems with SIDS.\n\ntl;dr Cribs are easy and cheap to make. Recalls are usually because of overcomplicated bullshit that was added to market toward anxious parents."
]
}
|
[] |
[] |
[
[],
[],
[
"https://www.verywellfamily.com/drop-side-crib-safety-issues-294016"
],
[],
[],
[],
[]
] |
|
2g5yle
|
why do laptops use fans -loud, annoying fans- while an iphone/ipad can run processor heavy apps for hours with no fan and not get hot?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2g5yle/eli5_why_do_laptops_use_fans_loud_annoying_fans/
|
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"cause laptop cpu's are more powerful than ipad processors. tablet and smartphone cpu's sacrifice processing power for less heat dissipation. ",
"Laptops and desktops have more powerful processors, graphics cards, memory and usually mechanical storage. More powerful processors and graphics can do more, but use more power to do so, more memory requires more power to use, and mechanical storage devices need to spin, which uses power and generates. An average laptop probably *idles* at 20-40W, and a desktop at 50-150W, and that's just when they're sitting there not really doing anything; they'll use more power when they're in use. All that energy being used has to go somewhere, and it's put out in the form of heat. We use fans to move air to move that heat away from the computer.\n\nMobile devices use far less power. They have solid state memory, which requires less power and generates less heat, far less powerful processors, which again generate less heat, and less memory which uses less power. Overall your phone probably uses around 5W, which means far less energy has to be dissipated.\n\nSo your phone/tabletonly has to get rid of a fraction of the heat that laptop/desktop can put out, which is can do by using small heatsinks and just radiating it away, whereas computers usually need far larger heatsinks and decent airflow.",
"Desktops / laptops use processors with much more power and features but this comes at the price of the high power usage and more heat output. These computers also need that extra power because the run more complex programs and more of that any any single given time. The os is generally much more robost as well which requires more power.\n\n Phones use much smaller and weaker processors that only use a little power and can get by off passive cooling. They can get away with this because the programs / apps are much more simple than their desktop counter parts + the os they use is much lighter."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
2xq32e
|
How were the Romans able to replenish so much of their manpower despite devastating losses in battles such as Cannae?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2xq32e/how_were_the_romans_able_to_replenish_so_much_of/
|
{
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"text": [
"I take it your question is less about Roman logistics and more about the specific fact that the forces at Cannae were effective crushed as a standing army, and how did Rome recover from something like that?\n\nFirst thing is first, with Cannae specifically there were very real and very profound consequences. Several city-states defected from Rome and turned to Carthage. Most estimates put Rome's total loss at over 70,000 with almost 40,000 of those being straight up casualties.\n\nThe Second Punic War devastated Rome.\n\nSo what was their response?\n\nWell, for lack of a better term, conscription.\n\nThe Carthaginians attempts to parley after Cannae and it was rejected. Instead, Rome conscripted *everyone* they could get their hands on, including peasants with no ties to land, as well as slaves. Furthermore, Rome flexed its legendary resilience by quickly adapting military doctrine and tactics, developing ways to counter Hannibal's classic flanking technique and changing their strategy to *never put that many people under one command again*, instead relying on much smaller, independent forces to face future foes.\n\nIn short, Rome survived because it was never too proud or too stubborn to find a way to make things work. Making the best of what they could gather, and getting mad rather than despairing. They took on totally new tactics and exploited the weakness of Carthage; attacking everywhere Hannibal was not.",
"Related question, it seemed that Rome the city itself was vulnerable to sacking after Cannae. When his subordinates suggested marching on Rome, why did Hannibal sat on that decision? Was he waiting on Carthage diplomatic manoeuvres?",
"The Roman army at that time was half composed of Latin allies so those losses weren't just being borne by Rome alone. This meant Rome could draw on a much larger base of manpower than other states who could only depend on their own population. \n\nThat said, even Cannae was extremely distressing and Rome was being defended by old men and young boys. They even formed a legion out of freed slaves equipped with captured arms taken from the temples.\n\nLastly they gained a breathing space when Fabius Cunctator was appointed dictator and he did the incredibly un-Roman thing of not fighting. He'd just shadow Hannibal's army and remain on the higher ground (where it'd be disadvantageous for Hannibal to attack). This kept his army intact and gave it time to train and build up cohesion, it hampered Hannibal since he couldn't disperse his army to forage for supplies. This went on for a while allowing Rome to rebuild her armies and let the other armies in Spain and Sicily go on offensive campaigns."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
4f9jkj
|
if a company has a labor strike, why can't they just fill their positions with temporary workers and let the strikers just continue to strike in perpetuity?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4f9jkj/eli5_if_a_company_has_a_labor_strike_why_cant/
|
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"text": [
"Those temps are called scabs, and it is not an uncommon occurrence. It definitely undermines their relationship with their regular work force, and often times results in violence, especially towards the scabs. ",
"The whole point of a union is that if everyone acts together it's really hard to do stuff like that. \n\nLike if one guy walks out you just fire him and get a new guy, but if every single person walks out all at once the company really needs to do something and get people to come back because totally replacing the entire workforce isn't simple and likely is going to be a huge problem if no one is there to train them or anything. ",
"Typically the guys who train the replacements are in the union too. If not then it's a really weak union. The white collar guys often have no clue how to operate the machinery and even if they did, they'd be striking too if their bosses told them to operate the machines. So then if everyone who has the knowledge to keep the plant running walks out, there really is no way for the management to produce anything during the strike.\nThere's real life experience to what happened. Ask your friends who are 50 and above who tried to fly in the 80s after the [PATCO strike.](_URL_0_)",
"They often try to, and if successful, they can destroy the union. \n\nWhy it doesn't work is the stronger unions have members who are skilled. You can't just take someone off the street and have them drive a semi or operate heavy machinery. Training them takes time, so the company is losing money while they are coming up to speed.\n\nThat is why companies like Walmart and McDonald's have largely avoided unionization, their work force isn't very skilled, and could be replaced with people off the street."
]
}
|
[] |
[] |
[
[],
[],
[
"https://en.wikipedia.org/wiki/Professional_Air_Traffic_Controllers_Organization_%281968%29"
],
[]
] |
||
1nruno
|
why do the carbons in graphene only have 3 bonds?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1nruno/why_do_the_carbons_in_graphene_only_have_3_bonds/
|
{
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"text": [
"The carbons form only three bonds because they are sp^2 hybridized (hence the -ene suffix). This means that there are only 3 hybrid orbitals that can form bonds, similar to the carbon in something like ethylene, H2C=CH2 (however, graphene doesn't have a double bond). I think the extra electron sits in a nonbonding p orbital that is perpendicular to the surface of the graphene, but don't quote me. Hybridization is useful to describe bonding in molecules, but isn't a good model for the electrons in graphene.\n\nGraphene can be made many different ways, the simplest is applying scotch tape to a chunk of graphite and pulling it off: layers of graphene like chunks stick to the tape.",
"Each carbon atom in graphene is sp2 hybridized and bonded to three other carbon atoms via sigma bonds. The remaining p orbital is perpendicular to the plane of the carbon atoms, but it is most certainly not non-bonding; in fact, these p orbitals give graphene its remarkable properties. \n\nThe electrons in the aforementioned p orbitals are delocalized due to resonance (or molecular orbitals, according to MO theory), similar to benzene, but on a much greater scale. Thus, there are partial double bonds in addition to the sigma bonds, and overall, each carbon has four bonds. ",
"The carbon atoms in graphing only have 3 *sigma* bonds. The fourth bond lies above and below the plane that the sigma bonded hexagons make. This bond actually incorporates all of the carbon atoms in the molecule and is what allows graphene to conduct electricity.",
"Everyone else here has been going on about how it's sp2 hybridised, but I guess I'll try to explain it in an easier way.\n\nElectron orbits the nucleus in \"clouds\" called orbitals. This is an extension of the old \"electron shell\" theory, but electrons are now a \"cloud\", or orbitals, around the nucleus, and there is a higher probability of finding an electron in these orbitals. Atoms form covalent bonds when orbitals overlap, in essence, sharing electrons.\n\nI will skip the basics of orbitals, but I'll jump into the shape of the orbital. Carbon has two kinds of orbitals, s orbitals and p orbitals. Often, outer orbitals (electrons in the valence shell) will \"hybridise\" to form different shapes. I will focus on one particular shape, the sp2 hybridisation of orbitals. \n\nAn sp2 hybridised orbital looks like this: _URL_2_ \n\nAs you can see, there are 3 orbitals outwards at angles of 120 degrees. These orbitals will overlap with each other, so each carbon forms 3 bonds with other carbons to form a hexagonal layer.\n\nNow, do you notice that there are the red orbitals sticking out? These are the remaining unbonded p-orbitals. They overlap with adjacent p-orbitals to form this: _URL_0_\n\nThese electrons can become delocalised and jump from atom to atom.This gives a very important property of graphene and graphite: the ability to conduct electricity.\n\nImages taken from google search, credits here:\n\n_URL_3_\n\n_URL_1_"
]
}
|
[] |
[] |
[
[],
[],
[],
[
"http://besocratic.colorado.edu/CLUE-Chemistry/chapters/graphics/ch3-11.jpg",
"http://besocratic.colorado.edu/CLUE-Chemistry/chapters/chapter3txt-3.html",
"http://www.chemguide.co.uk/basicorg/bonding/sp2.GIF",
"http://www.chemguide.co.uk/basicorg/bonding/ethene.html"
]
] |
||
2vom0g
|
why is it so hard for reddit to keep the site from crashing
|
Why am I buying gold if they are still having serious issues?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2vom0g/eli5_why_is_it_so_hard_for_reddit_to_keep_the/
|
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"text": [
"Buying gold more often keeps it from crashing. And if you've noticed they don't often meet the daily goal.",
"My guess is that they aren't making enough money to pay for the server time required for the number of users. The vast majority of redditors don't ever pay a dime to use the site and judging by the relatively low cost of advertising on reddit users here must be more difficult to convert into sales.",
"Not hitting the daily Gold goal often + Less ads = less revenue = worse servers + heavy load = more crashes. \n \nTL:DR bad servers"
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
3lp8vu
|
How did Polish pilots come to fly in the RAF during the Second World War?
|
As I understand many Polish (and other eastern European) pilots went to Britain and we're absorbed into the RAF. How did they get there baring in mind that Poland was taken very quickly by Nazi Germany and the USSR. How did they escape?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3lp8vu/how_did_polish_pilots_come_to_fly_in_the_raf/
|
{
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"cv8d5y7"
],
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],
"text": [
"After the German and Soviet invasions, substantial numbers of Polish military personnel escaped to neutral countries, primarily Romania, Hungary, Lithuania and Latvia, where they were interned. Air force personnel mostly evacuated to Romania, from where significant numbers made it to France either overland via Yugoslavia and Italy (still neutral at the time), or by boat; the internment camps weren't very closely guarded, and the Polish government in exile worked hard to assist with transport.\n\nPolish air force units were then formed in both France and Great Britain (around 7,500 personnel in the former, 2,500 in the latter), though neither were particularly enthusiastic about it, the French mostly assigning obsolescent aircraft, the RAF forming two bomber squadrons flying Fairey Battles. Following the fall of France, Polish units were evacuated to the UK from western French ports in Operation Aerial, allowing the RAF to form a further two bomber squadrons and two fighter squadrons."
]
}
|
[] |
[] |
[
[]
] |
|
bslycj
|
what is the core of the earth made of, how does it stay molten, and what would the impact of it cooling be?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bslycj/eli5_what_is_the_core_of_the_earth_made_of_how/
|
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"text": [
"It has a solid iron and nickel core surrounded by a liquid outer core mostly of the same metals. It stays molten due to the immense pressure of all the mass above it, generating heat.\n\nThe liquid core is believed to be the source of the planet's magnetic field. If you were to magically cool it and harden it, the planet would lose much of its magnetic field which would expose the surface to significantly more solar radiation, likely resulting in the planet becoming much less if at all habitable.",
"As best scientists can currently tell, the core is made up of a nickle-iron alloy. There is a solid inner core and a liquid outer core.\n\nThe liquid outer core stays molten simply because it lacks an easy way to cool. The Earth's mantle and crust doesn't provide very effective heat transfer from the core out to space so the outer/liquid core stays hot simply because the heat has nowhere to go.\n\nAs far as what would happen if it cooled, well it's actually a question of when. The earth's core is already cooling, and has been for billions of years. When the core finally cools fully, many things will happen, basically none of them good. The earth would lose its magnetic field and tectonic plates will stop moving are among the two biggest, both would essentially make the planet uninhabitable in the long run.\n\nFortunately we still have several billions years before this occurs.",
"The outer core is liquid iron and nickel (mostly). The inner core is solid and believed to be made of an iron-nickel alloy with some other elements (it's never been directly measured).\n\nIt doesn't \"stay\" molten, it simply takes a long time to cool down. We're talking billions of years. This will likely never happen though, as our Sun will probably turn into a Red Giant and engulf everything up to Mars long before Earth's core manages to cool.\n\nIf it did cool down however, we'd all be dead. The core is what creates Earth's magnetic field, which protects us from things like cosmic radiation and solar winds.",
"The solid core was deduced by seismologists studying earthquakes in New Zealand in the 1930s, because sensitive seismographs around the globe picked up the earthquake, but not as though the shockwave traveled directly point to point in a straight line, but instead it took longer to arrive than that. The delay made sense if the shockwave had to travel across the surface of the solid core as a reflection, and the delay suggests a core of 2400 km in diameter.\n\n & #x200B;\n\nThe inner Earth, outside the core, is molten due to two sources: primordial heat from the formation of the Earth, and radioactive decay."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
68eeh5
|
why do we still laugh at jokes we have heard before?
|
One of my favourite movies is Hot Fuzz even though I've watched it more times that I can count. In life, movies, tv, or any kind of entertainment -- why are many jokes still funny even if you've seen or heard them before?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/68eeh5/eli5_why_do_we_still_laugh_at_jokes_we_have_heard/
|
{
"a_id": [
"dgxtwig"
],
"score": [
5
],
"text": [
"If I hide behind your dresser and pop out and scare you, why would I be able to repeat that effect? Your mind or body still transmit information, whether it's new or old information is irrelevant. It still triggers those emotions in the same way. Not to mention mediums of entertainment are usually enjoyed with a heavily suspended disbelief - so we allow ourselves to forget we know what will happen the same way we allow ourselves to forget Johnny Depp is an actor and not actually a pirate or a guy with scissors for hands."
]
}
|
[] |
[] |
[
[]
] |
|
372dew
|
Are there any moons we know of that rotate the planet at the same rate that the planet spins?
|
If the rotation of the moon/rotating object matched the planet's rotation in terms of degrees, it would always be visible. Similar to how one side of the moon is always pointing towards earth. I was wondering if there is a planet where one spot on the planet always sees the moon at the same point in the sky?
|
askscience
|
http://www.reddit.com/r/askscience/comments/372dew/are_there_any_moons_we_know_of_that_rotate_the/
|
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"text": [
"The term you're looking for is geosynchronous orbit. I don't know of any moons in such an orbit.",
"There is no planet like this, but [Pluto](_URL_2_) and its moon [Charon](_URL_1_) have this property. They are mutually [tidally locked](_URL_0_).",
"As another commenter said, Pluto and Charon are mutually locked.\n\nThe important thing to note with this question - all planets with one moon will eventually end up in this situation given enough time. The Earth's rotation is continually slowing and eventually it's rotation will match the orbital period of the moon.\n\nHowever in Earth's case the sun will become a red giant and destroy the Earth long before Earth and moon have a chance to reach this state."
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Tidal_locking",
"http://en.wikipedia.org/wiki/Charon_(moon\\)",
"http://en.wikipedia.org/wiki/Pluto"
],
[]
] |
|
o6j0o
|
how does clicking a pen to the "closed" position prevent it from drying out?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/o6j0o/eli5_how_does_clicking_a_pen_to_the_closed/
|
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"Ball point pens don't dry out. Are you talking about ball point pens?",
"They're put in the \"closed\" position to prevent them accidentally writing all over you. The ink comes out when the ball (in the ball-point) rolls and exposes it.",
"Other than protecting the ink from getting all over the place, I believe having the pen in the closed position only serves to prevent anything from clogging the ball-point mechanism.",
"As people have mentioned, ball point pens don't dry out (quickly anyway). Pens that are effected like gel, have a lid. Markers also have a lid, but are basically a sponge in ink",
"It doesn't. However, the sound and feel of clicking a pen is enjoyable. \n\n\n",
"It's just there so the ink doesn't go everywhere. Ballpoint pens don't dry out because they use oil based ink. Other kinds of pens-gel pens, markers and fountain pens- do dry out because their inks are water based (though sharpie markers are alcohol based). ",
"It's because there are tiny, invisible-to-the-eye pen goblins in the body of the pen. They continually lick the tip of the pen, which keeps it moist and lubricated.",
"Ball pens don't dry. Cool huh? \n\nIf you open a ball pen of any kind, you'll see that the other end is open too."
]
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|
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1rw1gf
|
what is a "mainframe" and why are people always trying to hack into it in movies?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1rw1gf/eli5_what_is_a_mainframe_and_why_are_people/
|
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"Mainframes are what we'd think of as big corporate servers or supercomputers. \n\nIf you roll the clock back not that many years anything important was stored on a company mainframe - usually they were custom built for big database applications. The same basic role still exists and IBM and HP and Dell and a few others sell equipment for this, but it no longer requires custom hardware to run on, so the terminology has largely fallen out of use. Now we just call them 'servers' because they're just a particular case of 'server', of which there are many varieties. \n\nThe IBM zEnterprise series are still occasionally branded as 'mainframes', or called servers, and then run in the 100k - > multiple millions price range. \n\nedit: Big database servers don't *require* custom hardware, but IBM produces custom CPU's and there are things like custom casings and cooling for it. That's generally beneficial, but you can get by using generic server parts too. "
]
}
|
[] |
[] |
[
[]
] |
||
4v6h8y
|
how do sea creatures manage to live in water that others regularly poop in, without getting sick or dying?
|
Edit: My vacation to Florida last week and the recent Rio 16 Olympics had me wondering the difference between humans swimming in human poop-water vs sea creature poop-water.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4v6h8y/eli5how_do_sea_creatures_manage_to_live_in_water/
|
{
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"As an analogy how do we manage to not getting sick breathing the air that someone somewhere is sneezing in?\n\n\nThere are creatures in the water who eat that poop and break it down so eventually the poop becomes harmless. \n\nIn the short time : there is dilution (even humans swimming in the river that collects poop water ) don't get sick. \n\nAnd there is biochemistry. Bacteria in human poop isn't as damaging to some sea creatures as it is to humans."
]
}
|
[] |
[] |
[
[]
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|
12igv2
|
Who did the U.S./Nato support in the Bosnian War?
|
I know Kosovo for sure. Ive read how well Kosvars treat Americans that travel to their country because of our teamed effort to aid them in the war.
* Are there any newly formed countries, as a result of the war, that admire America the way Kosovo does?
* Vice-versa, which countries despise America for their role? Or are they just sour in general about Nato taking a side. I was born in 86' and was too young to really know what was going on nor did I ever learn about it in school.
Ive learned that Serbia was an aggressor in the war. I went to Belgrade over the summer, completely oblivious to the fact, but I noticed no negativism in regards to my presence being an American
* Why did U.S./Nato chose the sides that they did? Did some of countries in the E.U. see this as an opportunity to strengthen their union/euro with the newly formed countries as a result of the war?
* Is there a particular reason why Kosovo did not join Albania consider 92% of Kosovo are Albanians? Can/will this happen in the future?
* It seems like the war began because of Muslims who wanted autonomy and the Christians. How come there is no similiar rift between Protestants and Catholics in America, considering they make up more than half?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/12igv2/who_did_the_usnato_support_in_the_bosnian_war/
|
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"Disclaimer: this is lay person experience \n\n > Vice-versa, which countries despise America for their role?\n\nI don't know if you went in or not but the military museum in Belgrade has a section on the 99 Kosovo Crisis at the end proudly showing part of a US bomber along with images of wounded Serbian civilians and a detailed map of NATO bombings and which countries allowed their airspace to be used, that came across as very resentful to the point that you would think that Serbia was happily sat by itself when NATO came to bomb it for no reason. But otherwise everyone was very friendly to me too (UK so also NATO) and there was no signs of such feeling anywhere else.",
"1. Why did the US/NATO chose the sides they did?\n\nYou had a well equipped army/force (various kinds of armored vehicles, artillery, even a small airforce, etc) on one side, the Army of the Republika Srpska (VRS), which were essentially the units of the previous state force, the Yugoslav Peoples Army (JNA), in which Serbs from Bosnia and Herzegovina served, against lightly armed Bosniaks and Croats, who in the beginning didn't even have real defence forces. Now the VRS was able to conquer about 70% of the whole of Bosnia in the course of several months. The VRS conducted ethnic cleansing, genocide and various other crimes against humanity on their territorry against Croats and Bosniaks. The pressure for the western governments to intervent grew over the course of the war. In 1995 they had finally to do something in Bosnia (in this year there were several big massacres which got a lot of publicity in the western media e. g. Srebrenica with 8000 civilians dead). So they helped the recently formed Army of the Republic of Bosnia and Herzegovina (Bosniak and Croat forces) with a bombing campaign.\n\n2. Why does Kosovo not join Albania?\n\nWell for the moment this is impossible, because Serbia views it still as a rebellious province. And culturally/religiously Kosovo was an important serbian region, with the oldest churches and monasteries. Maybe at some point in the future Kosovo will join Albania, but that's just speculation.\n\n3. Why does not the same happen in the US?\n\nWell the situation is completely different. Yugoslavia was a multinational/ -ethnic/ -religious state that was only held together through the charisma of Tito and nothing else. It was not really a natural construct and every now and then bloody wars were fought in the Balkans between the ethnic groups and the nations (1912, 1913, 1914-1918, 1942-1945 and finally 1991-1999). Now as soon as Tito died in 1980, the problems came to the surface and it started to break apart.",
"I am a political scientist and this is my regional specialty. As such, I am not a historian but I think I can help. \n\nFirst, many Americans treat the wars in Slovenia, Croatia, Bosnia, and Kosovo as all one war. The first three arguably could be, but Kosovo is a very different situation. If you want to get into why, let me know and I will elaborate. This is an important distinction for many of these questions. \n\n1. Kosovo is the only formed country that feels completely that way, however the Bosniaks (Bosnian Muslims) are quite happy with the US, as evidenced by the response Secretary Clinton got there just this week. Interestingly though, that sentiment in Kosovo is waning as they feel they were promised independence, and in practice, they are not all the way there yet. \n\n2. No one despises America for their role as a country. The Republika Srpska (Serb part of Bosnia) would probably be the most likely to despise the US, but most of the displeasure I have heard is with the international response post-conflict. The Serbs were consistently called the \"bad guys\" in the conflict and in both conflicts, Croats/Bosniaks and Kosovo Albanians did some pretty nasty stuff to Serbs as well. However, there are some infamous war criminals (especially Croatians and Kosovo Albanians) who managed to not got prosecuted and this has lead to resentment towards the international community for demonizing one side in the wars. \n\n3. The EU did not see this as an opportunity to expand. Instead, the only EU foreign policy inducement tool they have is dangling the carrot of EU ascension. As such, they have since tried to get major political reform (working in Croatia, Slovenia, arguably in Macedonia), but not working too well in Bosnia and Serbia. If they could get these countries to reform how they want without offering ascension, I think they would. \n\n4. The EU/NATO/US would have never allowed it. There has been a constant concern about greater Balkans rhetoric, and if Kosovo joined with Albania to create greater Albania, the worry was that Serbia and Croatia would split up Bosnia, Greece may grab Macedonia, Bulgaria may grab some territory etc... Even if they want to, I doubt they would ever be allowed to in the foreseeable future with such an international presence there. \n\n5. That is a very simplistic view of the conflict and not why it started at all. In the Balkans, religion was simply a proxy used for ethnic identity. There are many different theories about why the wars occurred and if you have specific questions about the two different conflicts I can answer. \n\nEdit: This is my personal favorite book that explains the events in the 80s that lead to the situations we are discussing. I think understanding what happened in the 80s with the insurgency in Kosovo, the rise of Milosevic, and other factors is important in understanding all the questions you ask. _URL_0_",
"The breakup of Yugoslavia is not an easy topic. Basically Yugoslavia was a federation consisting of several different regions and population. Although ethnic and language similarities those regions had sometimes very different histories. I don't want to go into details but the region was largely ruled by foreign countries with a major influence from the Ottomans, Austrian, Hungarians. Especially the long and slowly fading rule of the Ottomans had a lasting influence. While Slovenia and Croatia ended up under Austrian influence. That's why Slovenia and Croatia are largely Catholics and Serbs are largely Orthodox.\n\nBut to make matters worse there were rarely strict boundaries and people not only moved but maybe a village refused to switch religion. Croatia has large parts with a Serbian minority. Bosnia was an even more complicated situation with Bosnians (Muslim), Croats (Catholic), Serbs (Orthodox).\n\nWhile Tito ruled Yugoslavia it all held together. But after his death Yugoslavia declined and nationalism was growing.\n\nSlovenia and Croatia were the first to declare independence in June 1991. But the Yugoslavian government wanted to use force to prevent it. This resulted in a short war in Slovenia (10 days war). Ironically the first casualty was a Slovenian pilot in the Yugoslav army killed when his helicopter was shot down by the Slovenian military. The war was quickly over because Slovenia was ethnically much more homogeneous. The situation in Croatia was much more dramatic. The Serbian minority in Croatia in turn declared themselves independent (Serbian Krajina). In 1992 Bosnia declared independence. The Croats declared themselves independent from Bosnia as the Croatian Republic of Herzeg-Bosnia and the Serbs declared themselves independent as Republika Srpska.\n\nAll of the new republics wanted to create ethnic homogeneous regions in such a highly mixed place. This resulted in the so called 'ethnic cleansing'. Former neighbours started to do really evil things to each other. The Bosnians, Croats, and Serbs all started operating concentration camps and committing atrocities.\n\nInitially the Serbs had the upper hand because the Yugoslav military was leaving them their heavy weapons. But the Croats were supported mainly by the US and Western Europe (Germany was a major contributor) and the Bosnians were also heavily supported by Arab countries and Mujahideen. The Croatian army eventually broke the Serbian resistance and occupied the Serbian Krajina.\n\nNATO intervened eventually with air strikes in Bosnia. Forcing all sides to negotiate. This resulted in the Dayton Agreement. Bosnia now consists of the Federation of Bosnia-Herzegovina (the Croat and Bosnian parts) and Republika Srpska (Serb part). There is still a Representative from the EU in place who's allowed to veto political decisions.\n\nTo answer why the US decided to support the Bosnians and Croats is not so easy. Some claim because of the human right violations committed by the Serbs. But then again the Bosnians and Croats committed human right violations on their own. Others of course claim that the US had an interest in destroying socialist Yugoslavia. But then again the US first favoured the status quo in Yugoslavia and was reluctant to support the independence.\n\n > Are there any newly formed countries, as a result of the war, that admire America the way Kosovo does?\n\nWell \"admiration\"... But Croats and Bosnians are of course grateful for US support. This does not mean that everyone will love you because you are an American. Last year a Kosovar shot at US soldiers in Frankfurt and killed two of them. There were Mujahideen fighting in Bosnia which are now considered to be close to Al Qaeda. And on the other hand just because a person is a Serb doesn't mean he'll hate you. The large majority of the people there are very decent and it doesn't really matter what their or your ethnicity is.\n",
" > Why does not the same happen in the US?\n\nNationalism directed at the country as a whole, rather than along ethnic lines. Also, \"protestantism\" in the United States refers to a number of distinct groups. There's about as much in common between a Baptist and a Lutheran as there is between a Methodist and a Catholic.\n\nRemember that our army is sworn to defend the country as a whole, and that the thought process behind our military (especially the National Guard) is geared toward the concept of the \"citizen soldier\". Soldiers are an extension of the people of our country, not a separate group in their own right, and no single group dominates our military."
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2lfwln
|
human consumption of other animal's milk.
|
Has the scientific process behind making milk ready for consumption just afforded us another choice of beverage? Is this an okay thing for humans to do? Is this why some people display symptoms of lactose intolerance? The literature is so biased that I cant decide my opinion on milk.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2lfwln/eli5_human_consumption_of_other_animals_milk/
|
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"\nWe've been eating animal milk far longer than any \"scientific process\" existed. For most of our history it was milk the goat/cow/buffalo and then drink the milk, period. Notably, milk is the _only_ thing that we eat that _is_ from humans, so...it seems strange that we'd call out a special case of a food-product that is externally generated, just because we have an internally generated analogue. \n\nThe vast majority of evidence suggests that animal milk is good and nutritious. Lactose intolerance would apply to both human milk and animal milk - it's the lactose in the milk, not the cow-in-the-milk that we have trouble with if we are lactose intolerant. \n\n",
"Yes, cow milk (and other milks that aren't human) is really just another choice of beverage if your body produces the right enzymes to digest them. \n\nHumans used to all lose their ability to produce lactase (the enzyme that breaks down lactose) once they got older, though the mutation to allow for continuous lactase production occurred multiple times in different human populations in the past. \n\nThere's nothing \"special\" about the milk that makes it harmful in the way that people going \"oh, it's *unnatural*! We weren't meant to do it!\" say, though excessive milk consumption does have negative effects for some people. In children, too much milk can sometimes cause intestinal bleeding, for example. ",
"Milk is pasteurized (heated quickly to kill germs) before being sent out to market. This has nothing to do with lactose intolerance. Lactose is a type of sugar naturally present in milk, and it's that sugar that gives some people stomach problems when they drink it. \n\nFor most of history, all mammals became lactose intolerant after being weaned. Several thousand years ago some human developed the ability to keep drinking milk after being weaned, which gave them a new, calorie rich food source that decreased their chances of starving, therefore increasing their chances to reproduce. \n\nSo milk isn't bad for you, but it's also not necessarily good, especially whole milk, which is high in fat. If you're eating a balanced diet you don't *need* milk, but if you like it and budget for the calories it's fine.",
"Just to provide more information, the genetic mutation (natural) that allowed certain human populations to continue to produce the enzyme lactase (natural) into adult hood are known as [lactase persistent](_URL_0_). This particular mutation was selected for in cultures which already consumed milk and milk products (naturally part of the peoples culture) and arose about 10,000 years ago (way before modern food industry got involved in milk production).\n\nIt is natural for some people to be ABLE to consume milk into adulthood without any consequence, it is equally natural for some people to be UNABLE to consume milk into adulthood and they typically experience the symptoms associated with lactose intolerance.\n\nIf you are concerned about the by-products associated with modern industrial milk production (e.g. hormones, pus, contaminants) then try different brands which advocate for better animal welfare and alternative milk production practices. It is really important to understand that these human production issues are inherently different then those associated with milk itself (e.g. being unable to digest lactose sugar in milk). "
]
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|
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|
2kb1ex
|
how are new "4k" tv's able to plat 4k content with old processors, but my new i5 computer lags with 4k content?
|
I have a pretty good machine. i5,16GB ram and 1TB SSHD but it lags at 4K.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2kb1ex/eli5how_are_new_4k_tvs_able_to_plat_4k_content/
|
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"My guess would be graphics performance of the chips. On your computer your GPU rather than your CPU will handle, by and large, the rendering of the images whereas TVs will have chips designed for rendering images and little else. If you set them both to find the billionth prime number your laptop would win hands down. If you had a animators/video editors' PC then the rendering would be no problem. \n\nThat's my guess anyway. ",
"The same way consoles run games years after they release after the hardware becomes inferior to their PC counterpart, dedication.\n\n\nYou see there is no clunky windows to run and the programming is lean and streamlined. Thus the most is made out of the power that's at hand."
]
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[] |
[] |
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[],
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|
2r7f1r
|
why can't divers fly after diving?
|
I read somewhere that it is to prevent Decompression Sickness, but I'm not so sure I grasp the idea of it. I mean, what happens when bubbles form then the diver decides to ride an airplane? Do gases mix? Does Nitrogen have any integral effect since air is mostly comprised of this gas?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2r7f1r/eli5_why_cant_divers_fly_after_diving/
|
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"You're right: the main gas involved is nitrogen. Basically, when we dive very deep, there's more pressure on our entire body, including our blood. More nitrogen dissolves into our blood than it would at a lower pressure (e.g. at sea level). If we come up too quickly from very deep, we can get \"the bends,\" which is a syndrome of pain and potentially organ damage from all that extra nitrogen un-dissolving and forming bubbles in our blood vessels. Blood has trouble flowing past those bubbles.\n\nThe problem with flying is that it lowers the pressure much more than just being at sea level (our ears popping is another effect of the pressure drop). This means there's another chance for nitrogen to un-dissolve and create bubbles in our blood vessels and tissues. Basically, you're creating a situation just like if you went from very deep in the water to the surface too quickly.",
"I read that question completely wrong... I was imagining a high diver jumping and then soaring off..."
]
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[] |
[] |
[
[],
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|
1qgxok
|
the revolutionary war; what caused it, and how was it regarded from an english perspective?
|
I was very intrigued by the new WW2 askreddit post, and was going to post there but I felt more like it was a question that I didn't understand so figured it fit better here! (I basically know the American side, just not the Brits).
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1qgxok/eli5_the_revolutionary_war_what_caused_it_and_how/
|
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"It started because King George was taxing the colonies above and beyond reason. The English people thought the colonists were being ungrateful."
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[] |
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[
[]
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|
1tkopg
|
Were there any economic interactions between the United States and the USSR during the Cold War?
|
Was the barrier of communism making it impossible for importing and exporting from both sides to take place? Or was there a standard trading system like the one in place today?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1tkopg/were_there_any_economic_interactions_between_the/
|
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"In 1972 the USSR bought 440 million bushels of wheat from the US, with more purchases in following years. Here's a paper from the St Louis Fed -\n_URL_0_ . I'll never find the link, but in the late 80s/early 90s The Economist made an editorial comment about Russia being in the grain market again, due to \"70 years of worse-than-expected winter weather in the Ukraine.\"",
"Tacking on another question: I've heard that we had to buy titanium from Russia through intermediaries to build the SR-71. Is that true?",
"I don't have a general answer to your question, but I can relate some specific details about how the USSR was part of the global trading system. \n\nI work in trade law, and there is an important case, Georgetown Steel Corp v. United States, from the Federal Circuit Court of Appeal in the context of anti-dumping and countervailing duty investigations. The decision was from 1987 if I'm not mistaken. \n\nBefore explaining the decision, I'll explain those terms. In trade, you sometimes have goods that are being imported at low prices and this is harming the domestic industry of the country, either because exporters are \"dumping\" goods because of excess supply, to gain market share, etc; or because the goods are subsidized unfairly by the government of the exporting country. (There are rules about what exactly is \"unfair\" subsidizing that I won't get into.) The remedy to these types of unfair trading practices is for the customs agency of the importing country to conduct an investigation into whether there is dumping and/or subsidizing and then impose anti-dumping duties or countervailing (anti-subsidy) duties on the specific type of goods under investigation (usually it's a very narrow range of goods) to counteract the injurious effect of the low-priced imports. All these rules existed under the General Agreement on Tariffs and Trade, the predecessor to the World Trade Organization (which was created in 1995).\n\nNow, in the Georgetown case, the context was a subsidy investigation against steel imported from Czechoslovakia. The court mentioned that there had been anti-dumping investigations against goods imported from the USSR and other so-called \"non-market economies\" - one I can remember off the top of my head, since you asked specifically about the USSR, is potash - however a subsidy investigation against such a country was new territory. \n\nThe court ultimately decided that the US couldn't conduct subsidy investigations against non-market economies since it was impossible to determine what constituted a subsidy in a centrally planned economy. \n\nAll that is to say that there was at least some normal trade going on between the US and eastern bloc countries, including the USSR. "
]
}
|
[] |
[] |
[
[
"http://research.stlouisfed.org/publications/review/73/10/Russian_Oct1973.pdf"
],
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[]
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|
7ftzoq
|
how does germany not have a crazy high rate of alcoholism and related crime when it has relaxed liquor laws?
|
Travelled to Germany and I could buy all sorts of beer in many stores and even drink in public. There does not seem to be more alcohol related incidents, violence or crime either
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7ftzoq/eli5_how_does_germany_not_have_a_crazy_high_rate/
|
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"People who are happy and secure generally don't drink to excess, or when they do, don't commit crimes. Germany has a strong economy, a strong social safety net, widely available substance abuse treatment, and a rather effective police and judiciary.\n\nAs various attempts at alcohol prohibition worldwide have proved, people will always get alcohol if they want it. It's a simple chemical any idiot can make at home. The way to reduce alcohol-related crime and health problems is to attack the things that cause problem drinking. Namely insecurity, anxiety, and untreated mental/psychological disorders.",
"Because they’re responsible about it. Germany is like the weird uncle who likes brandy after dinner while the US is your underage little brother getting hammered on Colt 45",
"An important aspect of this is that young people are introduced to alcohol as a perfectly normal thing, and are taught to drink responsibly. Since you don't have to hide away and drink in secret, it's much easier for people to keep an eye on you -- a bartender can say, \"I think you've had enough sir, and I'm going to call a cab,\" which your rebellious friends at your secret party probably won't.\n\nAt 16, you're allowed to buy beer and wine, but not spirits. The thinking here is that beer and wine have much lower alcohol content, and it's far more difficult to give yourself alcohol poisoning. It's not even possible to drink enough beer to become ill: you'll throw up first, and unless you're unfortunate enough to choke on your own vomit, you'll simply wake up feeling terrible and smelling bad, having hopefully learned a lesson before you develop a dependency.\n\nThere is also a prevailing cultural attitude that approves of drinking, but not of drunkenness.\n\nA few years ago, there was some concern about what appeared to be a fashion among youngsters for binge drinking. Those fears were probably exaggerated, but it was a hot topic for quite some time. The government and police responded not by clamping down, but with a PR campaign: ads featured graphic pictures of teenagers passed out in pools of their own vomit and urine, and they were even printed on beer mats -- [here's an example, not for the faint-hearted and probably NSFW](_URL_0_). The subliminal message was: \"Are you sure this is a cool thing to do?\"\n\nI don't have any statistics on how effective this campaign was, but I haven't seen any discussion about binge drinking for ages. But it demonstrates how the focus is always more on awareness than demonization: notice the slogan, \"Don't drink too much,\" as opposed to \"Don't drink.\"",
"The causality runs the other direction. Stricter alcohol laws are usually the result of widespread alcohol abuse, not cause of responsible drinking. They also rarely work.\n\nIts economic stability, cultural focus on beer rather than harder liquor, and any number of other reasons, Germany has not had enough of a problem to have to enact such laws."
]
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[] |
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[],
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"http://p5.focus.de/img/fotos/crop722580/2932716551-w1200-h627-o-q75-p5/fit-komasaufen-dpa.jpg"
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|
31m1nh
|
what does it mean to "soft reboot" my android device?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/31m1nh/eli5_what_does_it_mean_to_soft_reboot_my_android/
|
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],
"text": [
"Soft reboot is when you actually go through the OS and choose the \"Reboot\" or \"Restart\" option, as opposed to a hard reboot, which is physically(or using the 5 second switch that is standard on most computing devices now) cutting the power and then turning it back on again."
]
}
|
[] |
[] |
[
[]
] |
||
a9wpjp
|
tesla’s fascination with the numbers 3 6 9
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a9wpjp/eli5_teslas_fascination_with_the_numbers_3_6_9/
|
{
"a_id": [
"ecn3zzu",
"ecn4vnz"
],
"score": [
2,
2
],
"text": [
"I remember from my studies that in middleage the 3 was a link to Catholic God (the trinity) and so 6 because is two times 3 and 9 because is three times 3, You can find this obsession with number in Dante's Divina commedia.",
"Because it leads to a quite attractive female per se Little Jonathan and the East Side Gentlemen"
]
}
|
[] |
[] |
[
[],
[]
] |
||
49z1rc
|
In what ways were European states forced to reform in order to defeat Napoleonic France?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/49z1rc/in_what_ways_were_european_states_forced_to/
|
{
"a_id": [
"d0w4vwi"
],
"score": [
12
],
"text": [
"The biggest change, militarily speaking, was in the size of militaries involved before the Wars of the French Revolution and after. To give you an example, the British army, on the eve of the American Revolution in 1775 was something like 48,000 soldiers over its entire empire. For a sense of comparison, Wellington had about 30,000 British soldiers (Not counting allied soldiers) just for the Battle of Waterloo in 1815. At the [Battle of Leipzig](_URL_1_) in 1813, the French army alone suffered more casualties than soldiers existed in the British army only a few decades prior. The French concept was called the [levee en masse](_URL_0_)\n\nBasically, war on this scale was completely unprecedented in history, and the necessity of raising such large military forces required changes in the states that supported them. In Britain, you see more influence going to the House of Commons along with greater governmental centralization. Soldiers also had to be supplied, so you needed vastly increased industrial output to produce the weapons, ammunition, clothing, and so on that they all required. \n\nAll in all, I've always thought that the Napoleonic Wars did away with the last real vestiges of European feudalism, at least in Great Britain, and after 1815, we see something approaching what we could consider the modern centralized state."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Lev%C3%A9e_en_masse",
"https://en.wikipedia.org/wiki/Battle_of_Leipzig"
]
] |
||
3s20u1
|
How did nobility/royalty prove who they were while traveling?
|
I'd like to know specifically about nobility traveling to far away places, like different continents.
Did they carry papers that would officially link them back to their country that would open doors for them? Did they just bring money and that would be like a royal passport?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3s20u1/how_did_nobilityroyalty_prove_who_they_were_while/
|
{
"a_id": [
"cwtd15p",
"cwtxb9a"
],
"score": [
34,
5
],
"text": [
"Could you specify what time period you're thinking of? It would vary a lot from civilization to civilization, and era.\n\nThere were a lot of things that could be used to distinguish people that would not have been easily replicated. Certain insignia like a signet ring, sceptre, or crown. Or official papers bearing the seal of their government, monarch, or whatever. Other times the size of a person's retinue would make it clear that they were a person of note.\n\nNow adays a diplomat presents his credentials to the other country's head of state, who then acknowledges them and accepts that diplomat as an emissary.",
"Before the invention of the steam ship and the railroad, travel was rather limited and it was mostly the upper classes that did it, bar some special circumstances such as going on the hajj, a pilgrimage or a military campaign or crusade.\n\nAn upper class person would travel in style, often with a large following, and people mostly trusted the claim that they were who they said they were.\n\nThe upper classes often travelled to their own estates or to allies, relatives or friends, who would be informed beforehand and prepared to recieve them - and be able to vouch for the arriving guests in case anyone thought to challenge them."
]
}
|
[] |
[] |
[
[],
[]
] |
|
2wxp89
|
when did most people in England start thinking of the royal family as their native leaders instead of foreign invaders?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2wxp89/when_did_most_people_in_england_start_thinking_of/
|
{
"a_id": [
"covammf"
],
"score": [
17
],
"text": [
"This is a very tricky question because it's not clear which royal family you're discussing. The last time the dynasty changed by foreign invasion was in the Glorious Revolution of 1688, and there was a *very* widespread effort among the elites in England, especially the Whig faction, to invite in the House of Orange and conspire against the Stuarts. Stuart loyalists, or Jacobites, were the main group that thought of the House of Orange and, later, the House of Hanover as foreign, but the Jacobites were deeply limited in their support due to the House of Stuart's association with A. Catholicism and B. Scottish nationalism and C. the French monarchy (the Bourbons were *very* close cousins to the Stuarts and Louis XIV would become the Stuarts' biggest sponsors), which meant that even the English Tories that might have had closet sympathy with them would find the sort of people that backed the Stuarts very difficult to work with. The House of Hanover, which inherited the throne after Queen Anne died childless, was not very popular at first: George I barely spoke English and had little interest in this distant island.\n\nBoth France and Spain continued to recognize James II's son \"James III\" as the rightful king of England, Scotland, and Ireland, and James \"The Old Pretender\" attempted an invasion of Scotland in 1715 to reclaim the throne, but was swiftly driven off. During the reign of George II, James's son Charles, or \"Bonnie Prince Charlie\" or \"The Young Pretender,\" attempted his own somewhat more credible invasion in 1745 that attracted support from disaffected Scottish people and Catholics across the United Kingdom, but they were decisively smashed at the Battle of Culloden. After Culloden in 1745 the idea of a Jacobite Stuart restoration became utterly implausible and the House of Hanover was clearly not going anywhere. There were still sympathetic old Jacobites, and there are even a few today, but there hasn't been a serious prospect of a restoration of the Stuart monarchy since 1745 (and, more realistically, since 1689)."
]
}
|
[] |
[] |
[
[]
] |
||
3ipu5g
|
why do dogs like tummy rubs but cats tease you with it but then attack you?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3ipu5g/eli5_why_do_dogs_like_tummy_rubs_but_cats_tease/
|
{
"a_id": [
"cuij46g",
"cuijed9",
"cuilyzb"
],
"score": [
42,
10,
14
],
"text": [
"A lot of cats (not all - I've got one that rolls on her back and meows at me if I *don't* rub her belly) don't like having their belly rubbed.\n\nThem rolling on the back is a trust thing - they're exposing their most vulnerable parts to you and trusting you not to take advantage of that.",
"Cats are usually attacking things that enter that area of their body. They jump on prey, bite around the head and kick with their back feet to quickly damage the prey. Dogs don't attack in that way. They tend to bite and cause trauma by shaking their heads. That's why dogs like play tug-of-way with their toys. ",
"Because dogs are fully domesticated pack animals that touch each other naturally and have also learned/evolved to appreciate the touch of a human. \nCats are not as \"domesticated\". They are basically a really lazy wild animal. They are supposed to live the majority of their life alone and so they have instincts to kill any food that comes by (because nobody else is going to feed them). The only reason cats are pets is because they are too small to kill us and they are good at rodent extermination. \nA full grown 500lb tiger acts EXACTLY like a house cat. The difference comes when you make your hand look like a dying bird, the tiger will murder you and eat your corpse. The house cat will just bite and scratch until you are in too much pain to keep \"playing\". "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
51f659
|
Why did it take semi automatic weapons so long to be developed?
|
One would think that as soon as a gun was invented that they would want to make semi and automatic weapons. However it took centuries before we saw one.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/51f659/why_did_it_take_semi_automatic_weapons_so_long_to/
|
{
"a_id": [
"d7bv1vg",
"d7c0n91"
],
"score": [
2,
3
],
"text": [
"The main problem is the difficulties inherent in gunsmithing. You need some very precise metallurgy and engineering to produce a semi-automatic firearm, and mass-production requires a very advanced level of machining and metalwork to produce something that won't explode in your hand.\n\nDuring the heyday of black-powder firearms, double-barrelled weapons were often used, and some manufacturers experimented with even more barrels, producing things like the Nock Volley Gun. However, these were expensive and required careful manufacture, which made them impractical as military firearms. Similarly, breech-loading mechanisms were developed, but they generally required hand-crafting and were delicate, meaning that they also could not be mass-produced. Further, black powder produces a great amount of byproduct, in the form of thick smoke and leftovers that can foul the workings of a firearm. \n\nThat byproduct was the main point preventing the development of semi-automatic weaponry after the widespread adoption of practical breech-loading rifles, although many models were produced. The development of 'smokeless' propellants around the close of the 19th century which produced a much smaller amount of fouling allowed the development of the mechanisms for practical semiautomatic firearms on a mass scale.",
"Self loading rifles (firearms callable of firing a round, extracting and loading a new one by itself) are a very complex mechanical enterprise that requires high tolerances and advanced knowledge of metallurgy. There are a few thing you need for a self loader. Firstly you need a method of loading the next round which the nature of muzzle loading muskets made this task impossible, plus powder had to be loaded in separately from the round adding additional complexity to self loading. A magazine with a spring-loaded follower may seem obvious to you but this took time to develop. Many repeater rifles used tubular magazines in the gun which prevented the use of pointed bullets.\n\nAnother must is a strong receiver that can withstand high pressures. One shot produces a lot of pressure but automatic or even semi-automatic fire prevents the pressure in the chamber from having time to lower. This is why modern rifles use intermediate cartridges (7.62x39, 5.45x39, 5.56x45) and not the large beefy rifle cartridges of older rifles like the Mosin or Lee-Enfeild (7.62x54, .303); those cartridges produce pressure that too high for controllable, useful automatic fire. \n\nAnother reason independent from mechanical problems was the beliefs of most armed forces until The First World War. It was a common belief that soldiers with access to magazine fed bolt action rifles would fire wildly and waste ammunition. Now try to convince them that soldiers with weapons that load rounds by themselves are a good idea. Self loaders may seem like the obvious way to go but their development took a lot more then the simple idea of rapid fire weapons.\n\nSources\nT.L. McNaugher \"M-16 Controversy\":\nSkennerton, Ian \"Small Arms Identification Series\""
]
}
|
[] |
[] |
[
[],
[]
] |
|
cb1tcq
|
why can cows and other animals constantly produce milk but humans cannot?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/cb1tcq/eli5_why_can_cows_and_other_animals_constantly/
|
{
"a_id": [
"etcfsrh",
"etcm8s0",
"etcs5im",
"etd03cs",
"etdm4vw"
],
"score": [
29,
2,
15,
57,
6
],
"text": [
"They can. That's what a wet nurse does. Milk supply stops when the demand stops, same for all mammals.",
"Dairy farmer here: cows reach peak production generally within 60 days after calving. From there continued production depends on a number of factors. She needs adequate food. She needs to be milked out 2+ times a day. Another pregnancy will reduce production, and it will usually slowly decline over the next seven months. Then there's a two month 'dry period' when the cow produces no milk. \n\n\nWoman (and cows) can lactate for years on end, however there will be ever decreasing amounts.",
"They don't. They only produce after becoming pregnant, and produce until the demand stops. This is true for all mammals. While a mother nurses, the draw of milk produces hormones which continues milk production. When she stops, these hormones are no longer released and milk production ceases.",
"All female mammals only produce milk after being pregnant. If you're thinking of dairy cows, they \"constantly\" produce milk because they are constantly being inseminated, going through pregnancy, giving birth, then having their babies taken away (and killed if male), and being artificially milked for human consumption. Then the cycle repeats until they aren't seen as being productive anymore, then they're killed. The same thing *could* be done to human women, but it would break a whole bunch of different laws (plus, you know, ethics) ....",
"They don’t, milk supply eventually dries up and have to be forcefully impregnated to keep the dairy industry afloat. Even wet-nurses eventually dry up."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
87j90s
|
How is action potential measured in a cell?
|
I'm a math and science tutor. One of my students is a 7th grader that is enrolled in a life science course. Right now they are learning about the nervous system. This student, who is naturally very inquisitive (and autistic), has a million questions. Right now he is trying to understand how biologists measure action potentials in an axon. I tried to explain the idea conceptually. I told him there were more ions in the extracellular space than the intracellular space. He isn't satisfied with this answer, however, because we keep coming across graphs on the internet that show the membrane potential measured in millivolts. How are these membrane potentials actually measured? Because I know that it couldn't be with a standard voltmeter. If someone could please explain this to me I would be most appreciative.
|
askscience
|
https://www.reddit.com/r/askscience/comments/87j90s/how_is_action_potential_measured_in_a_cell/
|
{
"a_id": [
"dwdblz6",
"dwdcfo9"
],
"score": [
8,
3
],
"text": [
"Hi there, as a biochemist studying ion channels I hope I can provide enough information to satisfy you and your student, or even better, whet your curiosity for more.\n\nAs to your question about how we measure membrane potentials. We take a glass electrode and stab a cell with it, then measure the voltage between the electrode (now continuous with the inside of the cell, and a reference electrode outside the cell. There is a lot more sophistication to the technique and many many variations that allow for extremely careful and accurate measurements of cells all the way down to the activity of a single protein in the membrane, but basically that's what we do. This technique is called \"Patch Clamp\" (technically what I described is a subset that technique called \"Whole cell\" patch clamp). [ref1](_URL_0_)\n\nThe technique was first developed in squid because they had a giant (meaning visible to the naked eye) axon that could be patch clamped using the tools available at the time. \n\nit isn't exactly that there are more ions outside the cell than inside the cell. What is more strictly true, is that for each different type of ion (at least the major ones used to generate action potentials: K+ Na+ Ca2+ and Cl-) the cell uses up some of its energy in the form of ATP to establish an electro-chemical gradient across the membrane.\n\nThe gradients established are: \n\nFor Sodium (Na+) about 14 mM (millimolar) inside, and about 145 mM outside.\n\nFor Potassium (K+) basically the opposite, about 150 mM inside and 4 mM outside\n\nFor Calcium (Ca2+) about 70 nM (that's 0.00007 mM) inside, and 2 mM outside.\n\nFor Chloride (Cl-) about 10 mM inside and 110 mM outside. \n\nThe concept that you need to grasp for action potentials in cells is that it is all controlled by proteins in the cell membrane. The cell membrane itself is made up of lipids and are extremely impermeable to ions. Ions only cross from inside to outside (or vice versa) if there is a protein called an ion channel in the membrane that opens to allow ions through. Additionally these ion channels can be extremely selective, meaning that when they open, only one type of ion can go through them.\n\nSo thinking about the system. We have a charged species separated by an impermeable membrane, that sets up an electrical potential, and when an ion channel opens current flows according to that potential.\n\nI'll keep the context to the action potential in a neuron. [ref2](_URL_1_)The rules of electrical impulses in biology follow the same laws as in physics, ohms law (voltage = current x resistance), but with a couple twists to make the units/scale and conditional factors (temperature, gas constant, Faraday constant) to fit the range that works best in biology. Ultimately we use these factors in an equation called the Nernst equation. This give us: Membrane potential of a given ion = -((temperature x gas constant)/(Faraday Constant x Charge on ion)) x natural log((concentration of ions outside the cell)/(concentration of ions inside the cell). [ref3](_URL_2_)\n\nIf you take the concentrations of ions I listed above and plug them into the Nernst equation, you'll see that for Na, the membrane potential is about +60 mV (millivolts), for K+ the membrane potential is about -98 mV and for Ca2+ the potential is about 137 mV. Since at \"rest\" most/all of the Na+ and Ca2+ channels are closed, the resting membrane potential is controlled mostly by K+ channels (which are open), and thus the cell membrane potential is around -60. \n\nAction potentials are triggered when a chemical stimulus (such as presence of a ligand (something that binds to a protein and turns on its activity) or a neurotransmitter (a specific subset of ligands) binds to an ion channel (in this case a Na+ or Ca2+ channel) and triggers it to open. When that happens, lets say for Na+ channels, the Na+ will now be able to cross the membrane and the membrane potential will move towards that of Na (+60 mV). At some threshold, the membrane potential becomes different enough from the resting potential, that other channels which are sensitive to changes in voltage, also activate. Suddenly many many channels (Na+ and Ca2+ type) are open and the the membrane potential rapidly depolarizes in what we refer to as an action potential. \n\nI did skip over a HUGE amount of detail, caveats, and specifics for this background, so please feel free to ask follow up questions, or for clarification (also if I didn't actually answer your question let me know and I'll try again). \n\n*edit, added refs",
"There are more contemporary variations on it in use today but good old-fashioned [patch clamp recording](_URL_1_) is how ion currents and action potentials are measured in a cell. \n\nThe basic idea, which was developed in the '60s-'70s, and for which several Nobel Prizes have been awarded, is that a very finely glass pipette tip is applied to a small patch of membrane, isolating a single ion channel (see the [image here](_URL_0_)). Ions fluxing through the channel generate a current that can be measured by an electrode in the pipette tip. This can be done in two modes: voltage-clamp and current-clamp. In the former case the voltage is held constant in order to measure ion flux through a channel. In the latter case the current is held constant, permitting the measurement of action potentials over time. "
]
}
|
[] |
[] |
[
[
"https://www.leica-microsystems.com/science-lab/the-patch-clamp-technique/",
"https://faculty.washington.edu/chudler/ap.html",
"http://www.physiologyweb.com/calculators/nernst_potential_calculator.html"
],
[
"https://imgur.com/d6xnZtr",
"https://en.wikipedia.org/wiki/Patch_clamp"
]
] |
|
2no258
|
what happens when a banana is bruised
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2no258/eli5what_happens_when_a_banana_is_bruised/
|
{
"a_id": [
"cmfk8mj"
],
"score": [
5
],
"text": [
"When part of the fruit starts to decay it releases a chemical called ethylene which signals other parts of the fruit that it's time to die as in the natural process of nature. Bananas also contain an enzyme called polyphenol oxidase, and the oxygen present in the air readily reacts with the enzyme found in the bananas. This oxidation reaction is seen as a rusting or browning of the banana's surface."
]
}
|
[] |
[] |
[
[]
] |
||
5l7vbp
|
are fabrics like linen really anti-microbial?
|
I've seen claims on websites selling linen that the fabric is anti-microbial or anti-bacterial. Is this true, and if so, how?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5l7vbp/eli5_are_fabrics_like_linen_really_antimicrobial/
|
{
"a_id": [
"dbw882k"
],
"score": [
2
],
"text": [
"An educated guess is that either the fabric has been treated with something, or that the fibers are woven tightly enough together that bacteria and microbes have difficulty passing through it. So while it is \"anti-bacterial\" it doesn't kill them on contact. \n\nHere is an album of someone showing the difference of a lab coat's weaving and a shirt, with enough magnification that you would be able to see individual skin cells. You can see how bacteria would have difficulty passing through something finely woven. \n_URL_0_"
]
}
|
[] |
[] |
[
[
"http://imgur.com/gallery/nBO8G"
]
] |
|
1yove7
|
If no information can be transmitted via quantum entanglement, how did we discover it in the first place?
|
Or do I have an incorrect understanding as to what constitutes information?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1yove7/if_no_information_can_be_transmitted_via_quantum/
|
{
"a_id": [
"cfmirpc",
"cfmpvm8"
],
"score": [
2,
2
],
"text": [
"Quantum entanglement was first hypothesized in a thought experiment originally thought out as an argument against the Copenhagen Interpretation of quantum mechanics. This thought experiment is now known as the [EPR paradox](_URL_1_) named Albert Einstein, Boris Podolsky and Nathan Rosen after the three people that proposed it. The thought experiment wasn't in direct disagreement with quantum mechanics, but it seemed to defy physical causality with by what Einstein famously referred to as \"spooky actions at a distance\". This thought experiment ultimately led to the discovery of quantum entanglement and it has later been directly or indirectly confirmed by for example [Bell's Inequality](_URL_0_).",
"I would like to sidestep the argument between Platypuskeeper, *et al.*\n\nInformation is only transferred if the actions by one person (B) will, in a predictable way, affect the results of measurements made by the other (A). Neither quantum nor classical correlation makes this possible. \n\nTo be specific, when B measures the color of his token, A does not know this, and cannot find out by making his own measurement. In fact, A cannot even determine that B exists. Information is transferred only when B reports his result to A by a conventional channel."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Bell%27s_inequality",
"http://en.wikipedia.org/wiki/EPR_paradox"
],
[]
] |
|
705s2a
|
How high can roller coasters be built?
|
Right now, the tallest roller coaster in the world is Kingda Ka, standing at an impressive 456 feet. I was wondering, from a physics perspective, just how high can roller coasters be built? Will we ever see coasters over 500 feet? 600? A thousand? At what point does the drop start to become dangerous in terms of G forces?
Thanks for answering my stupid questions :P
|
askscience
|
https://www.reddit.com/r/askscience/comments/705s2a/how_high_can_roller_coasters_be_built/
|
{
"a_id": [
"dn1018j",
"dn19fri",
"dn1018j",
"dn19fri"
],
"score": [
6,
3,
6,
3
],
"text": [
"roller coasters are already being limited in the max Gs they induce \n\n4-6 Gs more than briefly can result in loss of consciousness ) \n\ncreating a taller one increases the cost a lot for support - with no \"real\" benefit beyond a \"wow\" factor (which, admittedly, IS something) \n\nsomewhat credible link about max Gs on various coasters\n_URL_0_\n",
"Actually the G force are linked to the curvature and the speed (which relate on height). So if you build a high roller coaster you can reduce the radius of curvature. \n\nThat said untrained person are pretty sensitive to G-force so you want to keep them low (no idea on the acceptable number for general public) \n\nThe problem would be construction and maintenance cost which would switch the question to the engineering category",
"roller coasters are already being limited in the max Gs they induce \n\n4-6 Gs more than briefly can result in loss of consciousness ) \n\ncreating a taller one increases the cost a lot for support - with no \"real\" benefit beyond a \"wow\" factor (which, admittedly, IS something) \n\nsomewhat credible link about max Gs on various coasters\n_URL_0_\n",
"Actually the G force are linked to the curvature and the speed (which relate on height). So if you build a high roller coaster you can reduce the radius of curvature. \n\nThat said untrained person are pretty sensitive to G-force so you want to keep them low (no idea on the acceptable number for general public) \n\nThe problem would be construction and maintenance cost which would switch the question to the engineering category"
]
}
|
[] |
[] |
[
[
"https://coasterpedia.net/wiki/Highest_g-force_on_a_roller_coaster"
],
[],
[
"https://coasterpedia.net/wiki/Highest_g-force_on_a_roller_coaster"
],
[]
] |
|
8o3oxv
|
When did people start snorting cocaine?
|
The inspiration for this question was my wondering specifically whether Sigmund Freud snorted cocaine when he famously experimented with the drug.
But it brings up the broader question: When and why did people begin snorting cocaine rather than administering it orally, intravenously, etc.? And how did that become the most popular \(in media portrayals at least\) route of administration?
Even more broadly, what's the history of people putting intoxicating substances up their noses?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8o3oxv/when_did_people_start_snorting_cocaine/
|
{
"a_id": [
"e00krq0"
],
"score": [
7
],
"text": [
"I don't know when people started snorting cocaine. In the late 19th century, the drug would either be taken orally, or injected intravenously. Think Sherlock Holmes, with this famous scene from the Sign of Four:\n\n > Sherlock Holmes took his bottle from the corner of the mantel\\-piece and his hypodermic syringe from its neat morocco case. With his long, white, nervous fingers he adjusted the delicate needle, and rolled back his left shirt\\-cuff. For some little time his eyes rested thoughtfully upon the sinewy forearm and wrist all dotted and scarred with innumerable puncture\\-marks. Finally he thrust the sharp point home, pressed down the tiny piston, and sank back into the velvet\\-lined arm\\-chair with a long sigh of satisfaction.\n\nThis is the famous \"seven percent solution,\" though a three percent solution became preferred as it was thought to have fewer side effects.\n\nSigmund Freud was one of cocaine's most ardent popularizers. Freud himself did not snort the drug, but rather drank it in a solution. Freud's famous essay is called Über Coca, and he's very explicit about how he took the drug. From section V \\(the Effect of Coca on the Healthy Human Body\\):\n\n > The first time I took 0.05cg. of *cocaïnum muriaticum* in a 1 & #37; water solution was when I was feeling slightly out of sorts from fatigue. This solution is rather viscous, somewhat opalescent, and has a strange aromatic smell. At first it has a bitter taste, which yields afterwards to a series of very pleasant aromatic flavors. Dry cocaine salt has the same smell and taste, but to a more concentrated degree.\n\nHe notes that later in the essay, higher concentrations cause some stomach upset, so he dissolved his cocaine in soda water.\n\nI should not that experimenting with medications on yourself in this period was not unusual \\-\\- John Snow would regularly inhale his own anesthetics and mark their effects \\(which likely led to his early death\\), and to make another Holmes connection, Sir Arthur Conan Doyle's first academic publication was in the BMJ on self\\-poisoning with escalating doses of gelsemium.\n\nCocaine was purified in the 1850s, and in the first half century of its existence, there was considerable excitement about its effects \\(and lack of side effects\\). It was thought to be particularly useful to treat morphine addiction \\(think William Halstead, who basically switched from morphine to cocaine\\). Cocaine was found in a number of over\\-the\\-counter products, most notably coca cola."
]
}
|
[] |
[] |
[
[]
] |
|
gv0gt
|
Why are African Americans usually lighter skinned than Africans?
|
My thought is that it is a result of interbreeding with light skinned people, but does it have merit? I only have my own empirical observations to base this on, and I know non-black people impregnated black people many times in American history.. but was it to the degree that it affected the majority of African Americans?
I know this may seem like a racist question but it is not.. just something I've wondered for several years and is the kind of thing you can only ask on an anonymous forum.
|
askscience
|
http://www.reddit.com/r/askscience/comments/gv0gt/why_are_african_americans_usually_lighter_skinned/
|
{
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"c1qhq3h",
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],
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"text": [
" > My thought is that it is a result of interbreeding with light skinned people\n\nYup.\n\n([ref](_URL_0_))",
"What makes you think that this is actually true? I'm not saying it isn't, but has this been approached scientifically?\n\nAlso, it is possible and likely that the genetic diversity throughout the African dark-skinned races is much much larger than in America. It would make sense that the slave trade \"imported/kidnapped\" people only from a few specific locations in Africa. That means you can't really make a general statement about the skin color of all Africans."
]
}
|
[] |
[] |
[
[
"http://www.ncbi.nlm.nih.gov/pubmed/12671003"
],
[]
] |
|
18bpb5
|
I've always heard that in the middle ages, people drank beer/mead instead of water because the water wasn't clean. Is this true, and if so, why wasn't everyone drunk/dehydrated all the time?
|
Also, aren't beer and mead made with water? Or was the problem keeping water clean, which the alcohol would accomplish?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/18bpb5/ive_always_heard_that_in_the_middle_ages_people/
|
{
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2
],
"text": [
"Not a historian, but a homebrewer and history enthusiast. The water is boiled in the process of making beer so this is why it was safer to drink than the water as any nasties in the water would be killed during this process. As for being drunk/dehydrated all the time this didn't happen because most of the beer consumed daily would have been small beer which would have been of a much lower alcohol content. It would have been made from the second or possibly third runnings from the grains. The first runnings would extract the largest amount of sugars from the grains and would have been used for making beer for export or special occasions (Belgian Tripel, Imperial Stouts, etc.). The grains would then be mashed again and the runnings from this would contain significantly less sugar. The amount of sugar in your wort is directly proportional to the amount of alcohol in you finished beer as this is what the yeast will eat and produce alcohol and CO2 as waste products. With the lower sugar content you end up with a much lower alcohol content suitable for everyday drinking without becoming too inebriated or dehydrated.",
"Here's a pretty thorough discussion about alcohol/drunkenness and beer from a few months back:\n\n_URL_0_\n\nLike FrictionGnome mentions, beer then wasn't what we think of as beer now."
]
}
|
[] |
[] |
[
[],
[
"http://www.reddit.com/r/AskHistorians/comments/14fvf8/if_beer_was_the_standard_drink_in_northern_europe/"
]
] |
|
14qf8y
|
How did Cavendish avoid/account for the gravitational attraction of the Earth affecting his experiment to determine G?
|
Henry Cavendish's 18th Century [experiment](_URL_0_) to determine the universal gravitational constant G involved measuring the gravitational attraction between two pairs of metal spheres, each pair consisting of one large and one small sphere.
The balls were affixed to rods that could rotate only in the plane horizontal to the Earth (so no vertical component), however if the rods were non-tangential to the Earth even by a fraction of a degree this would induce vertical motion in the balls as they rotated, therefore their rotational motion has a vertical component to be considered).
Additionally, the Earth does not produce a perfect uniform gravitational field which could surely skew his results further; the g-field may have been stronger at one sphere than at the other?
How did he ignore or account for these sources of error? I know that they are minute and often ignored but compared to the minuscule forces of attraction between the balls could they hold significance?
|
askscience
|
http://www.reddit.com/r/askscience/comments/14qf8y/how_did_cavendish_avoidaccount_for_the/
|
{
"a_id": [
"c7fsojf"
],
"score": [
2
],
"text": [
"It's rather easy to make the rods perfectly tangential to earths gravity by making them level. Just adjust the setup so that the weights don't rotate at all when left alone."
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Cavendish_experiment"
] |
[
[]
] |
|
17um5r
|
Is it possible for an earth-like planet to have a ring around it?
|
Or would the ring effect it?
|
askscience
|
http://www.reddit.com/r/askscience/comments/17um5r/is_it_possible_for_an_earthlike_planet_to_have_a/
|
{
"a_id": [
"c88ytvl",
"c890j31"
],
"score": [
3,
2
],
"text": [
"Yes, terrestrial planets can have rings.",
"Yes, just imagine breaking our moon into pebbles."
]
}
|
[] |
[] |
[
[],
[]
] |
|
4tjcz7
|
Did JFK actually say he wanted to "Shatter the CIA into a thousand pieces and scatter it to the winds"?
|
I've heard it attributed to him a lot, often the context given is that it was after the Bay of Pigs. Looking around a bit I can't seem to find a solid source, just people parroting the quote.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4tjcz7/did_jfk_actually_say_he_wanted_to_shatter_the_cia/
|
{
"a_id": [
"d5i4g9z"
],
"score": [
62
],
"text": [
"Vincent Bugliosi (former prosecutor in the Charles Manson trial, author of a careful, skeptical book about the Kennedy assassination), writes:\n\n > Whatever the CIA's short laundry list of dissatisfactions (some merely illusory, some real) with Kennedy, as I discuss later in the anti-Castro Cuban exile section of this book, Kennedy was highly disturbed with the CIA for its incompetence and its having misled him on the probable success of the Bay of Pigs invasion in 1961. Perhaps the most famous alleged quote from Kennedy about his animus toward the CIA after the Bay of Pigs debacle was that he wanted \"to splinter the CIA into a thousand pieces and scatter it to the winds.\" But in the two and a half years after the attempted invasion he never did anything remotely close to this, and it is not known to whom he supposedly said these words. The New York Times only said that Kennedy made this statement \"to one of the highest officials of his administration.\"\n \nVincent Bugliosi, _Reclaiming History: The Assassination of President John F. Kennedy_, page 1189.\n\nThe New York Times article in question is: \"[C.I.A.: Maker of Policy, or Tool?](_URL_0_)\", New York Times (April 25, 1966). It is on the second page of the article, under the heading of \"Kennedy's bitterness,\" and the specific quote there is \"splinter the C.I.A. in a thousand pieces and scatter it to the winds.\" \n\nThis appears to be the original source of the quote in print? In any case, it is an interesting round-about: the article is really about public perceptions of the CIA, and how they get blamed for lots of things there isn't any evidence for. Not entirely ironic that this quote is most used by people trying to establish a CIA motivation for killing JFK.\n\nWhich is to say: the quote's origins appear to be an anonymous source in the New York Times in 1966, which credits it (without saying whether it is direct or indirect credit) to a high-level administration official. It's not entirely implausible. But it's got a lot of gauze around it, as far as quotes go."
]
}
|
[] |
[] |
[
[
"http://query.nytimes.com/mem/archive/pdf?res=9400E4DB1639E63BBC4D51DFB266838D679EDE"
]
] |
|
3mk7x0
|
why is it still not commonplace to install antivirus software on on mac computers?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3mk7x0/eli5_why_is_it_still_not_commonplace_to_install/
|
{
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"cvfoqfv"
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],
"text": [
"Simple. It's already integrated in the OS.\n\n All versions of OS X since 10.6.7 have been able to detect known Mac malware in downloaded files, and to block insecure web plugins. This feature is transparent to the user. Internally Apple calls it \"XProtect.\"\n\nRead [this](_URL_0_) thread on _URL_1_ for further information."
]
}
|
[] |
[] |
[
[
"https://discussions.apple.com/thread/6624843",
"apple.com"
]
] |
||
mt5i9
|
How did men study during the Enlightenment?
|
I'm reading *Quicksilver* (I'm sure some of you guys love that book) and Stephenson always talks about the characters studying. For those who haven't read it, it takes place in the middle 1600's and early 1700's and two themes are intelligence and natural philosophy. However, the way he talks about studying sounds foreign. Would they just buy Euclid's *Elements* or Descartes and read through them (taking notes)? Where would they buy these books? Were they expensive? Any other info on how academics and independent study worked back then would be awesome too!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/mt5i9/how_did_men_study_during_the_enlightenment/
|
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"Disclaimer: I'm a history student, but probably not much more knowledgeable about this subject than a layman. Anyway, I'm not sure whether this answers your question exactly, but hopefully you'll find it interesting. \n\nWhat differentiates academic study during the enlightenment from the middle ages, is the abandonment of universities in favor of a decentralized community of scholars, often called [the republic of letters.](_URL_0_) The \"natural philosophers\" found in Stephenson's book lived during the heyday of this intellectual community. \n\nMy understanding is that the republic of letters emerged because people became dissatisfied with how things worked at the universities. During the middle ages (from the 12th century or so), universities starting popping up all over Europe. These universities organized subjects into *trivium* and *quadrivium*, terms taken from Roman times. Trivium consisted of grammar, logic and rhetoric, whilst quadrivium consisted of arithmetic, astronomy, geometry and music. These subjects were studied by all students, similarly to how all American university students study liberal arts today. After the introductory studies, students would go on to study either medicine, law or theology. Universities largely became institutions for educating civil servants and the clergy. \n\nIn addition, a academic tradition developed at the medieval universities, which is known as scholasticism, with representatives like Thomas Aquinas. They basically studied authors like Aristotle, and tried to fit the texts into an orthodox christian perspective. \n\nAs you see, there wasn't much room for actual scientific thought, and this explains why enlightenment scholars established themselves outside of the established universities. In regards to information about the republic of letters, I suggest reading the Wikipedia article I linked, as it seems pretty good. \n\n\n",
"Not exactly what you asked, but relevant enough I think.\n\n[This article](_URL_0_) discussing the google book agreements a couple of years ago deals with the republic of letters, the use and abuse of copyright stemming from this, and knowledge for the public good in the digital world. It is *very* long. \n\nWhile the article is very cautious about it, I do think there is something in the comparison between the revolutionary utopian idealism of enlightenment in the 18th Century, and the idealism of the power of the internet.\n\n > The eighteenth century imagined the Republic of Letters as a realm with no police, no boundaries, and no inequalities other than those determined by talent. Anyone could join it by exercising the two main attributes of citizenship, writing and reading. Writers formulated ideas, and readers judged them. Thanks to the power of the printed word, the judgments spread in widening circles, and the strongest arguments won.\n\n > The word also spread by written letters, for the eighteenth century was a great era of epistolary exchange. Read through the correspondence of Voltaire, Rousseau, Franklin, and Jefferson—each filling about fifty volumes—and you can watch the Republic of Letters in operation. All four writers debated all the issues of their day in a steady stream of letters, which crisscrossed Europe and America in a transatlantic information network.\n\n...\n\n > You cannot legislate Enlightenment, but you can set rules of the game to protect the public interest. Libraries represent the public good. They are not businesses, but they must cover their costs. They need a business plan. Think of the old motto of Con Edison when it had to tear up New York’s streets in order to get at the infrastructure beneath them: “Dig we must.” Libraries say, “Digitize we must.” But not on any terms. We must do it in the interest of the public, and that means holding the digitizers responsible to the citizenry.\n\n > It would be naive to identify the Internet with the Enlightenment. It has the potential to diffuse knowledge beyond anything imagined by Jefferson; but while it was being constructed, link by hyperlink, commercial interests did not sit idly on the sidelines. They want to control the game, to take it over, to own it. They compete among themselves, of course, but so ferociously that they kill each other off. Their struggle for survival is leading toward an oligopoly; and whoever may win, the victory could mean a defeat for the public good.\n",
"I should be doing a history essay right now, so this response will be short, but I just thought I'd stop by to suggest an author that you might find interesting.\n\n[Steven Shapin](_URL_1_)\n\nHe is an academic who has taken a sociological approach to the study of how scientific knowledge is formed. He's written a number of things, his last publication was [last year.](_URL_0_)\n\nSome of it can appear fairly polemical, but this is largely his response to arguments he manages to get into with scientists who misunderstand him and think he is discrediting their work. He isn't. And the points he raises do serve to challenge your understanding of what exactly 'science' and 'learning' actually are. \n\nSorry I don't have time to go into it more myself, but I hope you find this as interesting as I do.\n\n[edit] I just realised, this comment may seem off topic - he talks often about the Enlightenment and the transmission of knowledge - books, etc. - so, relevant in that sense. Hope that helps.",
"Disclaimer: I'm a history student, but probably not much more knowledgeable about this subject than a layman. Anyway, I'm not sure whether this answers your question exactly, but hopefully you'll find it interesting. \n\nWhat differentiates academic study during the enlightenment from the middle ages, is the abandonment of universities in favor of a decentralized community of scholars, often called [the republic of letters.](_URL_0_) The \"natural philosophers\" found in Stephenson's book lived during the heyday of this intellectual community. \n\nMy understanding is that the republic of letters emerged because people became dissatisfied with how things worked at the universities. During the middle ages (from the 12th century or so), universities starting popping up all over Europe. These universities organized subjects into *trivium* and *quadrivium*, terms taken from Roman times. Trivium consisted of grammar, logic and rhetoric, whilst quadrivium consisted of arithmetic, astronomy, geometry and music. These subjects were studied by all students, similarly to how all American university students study liberal arts today. After the introductory studies, students would go on to study either medicine, law or theology. Universities largely became institutions for educating civil servants and the clergy. \n\nIn addition, a academic tradition developed at the medieval universities, which is known as scholasticism, with representatives like Thomas Aquinas. They basically studied authors like Aristotle, and tried to fit the texts into an orthodox christian perspective. \n\nAs you see, there wasn't much room for actual scientific thought, and this explains why enlightenment scholars established themselves outside of the established universities. In regards to information about the republic of letters, I suggest reading the Wikipedia article I linked, as it seems pretty good. \n\n\n",
"Not exactly what you asked, but relevant enough I think.\n\n[This article](_URL_0_) discussing the google book agreements a couple of years ago deals with the republic of letters, the use and abuse of copyright stemming from this, and knowledge for the public good in the digital world. It is *very* long. \n\nWhile the article is very cautious about it, I do think there is something in the comparison between the revolutionary utopian idealism of enlightenment in the 18th Century, and the idealism of the power of the internet.\n\n > The eighteenth century imagined the Republic of Letters as a realm with no police, no boundaries, and no inequalities other than those determined by talent. Anyone could join it by exercising the two main attributes of citizenship, writing and reading. Writers formulated ideas, and readers judged them. Thanks to the power of the printed word, the judgments spread in widening circles, and the strongest arguments won.\n\n > The word also spread by written letters, for the eighteenth century was a great era of epistolary exchange. Read through the correspondence of Voltaire, Rousseau, Franklin, and Jefferson—each filling about fifty volumes—and you can watch the Republic of Letters in operation. All four writers debated all the issues of their day in a steady stream of letters, which crisscrossed Europe and America in a transatlantic information network.\n\n...\n\n > You cannot legislate Enlightenment, but you can set rules of the game to protect the public interest. Libraries represent the public good. They are not businesses, but they must cover their costs. They need a business plan. Think of the old motto of Con Edison when it had to tear up New York’s streets in order to get at the infrastructure beneath them: “Dig we must.” Libraries say, “Digitize we must.” But not on any terms. We must do it in the interest of the public, and that means holding the digitizers responsible to the citizenry.\n\n > It would be naive to identify the Internet with the Enlightenment. It has the potential to diffuse knowledge beyond anything imagined by Jefferson; but while it was being constructed, link by hyperlink, commercial interests did not sit idly on the sidelines. They want to control the game, to take it over, to own it. They compete among themselves, of course, but so ferociously that they kill each other off. Their struggle for survival is leading toward an oligopoly; and whoever may win, the victory could mean a defeat for the public good.\n",
"I should be doing a history essay right now, so this response will be short, but I just thought I'd stop by to suggest an author that you might find interesting.\n\n[Steven Shapin](_URL_1_)\n\nHe is an academic who has taken a sociological approach to the study of how scientific knowledge is formed. He's written a number of things, his last publication was [last year.](_URL_0_)\n\nSome of it can appear fairly polemical, but this is largely his response to arguments he manages to get into with scientists who misunderstand him and think he is discrediting their work. He isn't. And the points he raises do serve to challenge your understanding of what exactly 'science' and 'learning' actually are. \n\nSorry I don't have time to go into it more myself, but I hope you find this as interesting as I do.\n\n[edit] I just realised, this comment may seem off topic - he talks often about the Enlightenment and the transmission of knowledge - books, etc. - so, relevant in that sense. Hope that helps."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Republic_of_Letters"
],
[
"http://www.nybooks.com/articles/archives/2009/feb/12/google-the-future-of-books/?pagination=false"
],
[
"http://books.google.co.uk/books?id=QB3Ag08CdtwC&printsec=frontcover&dq=steve+shapin+never+pure&hl=en&ei=WH7VTo_qBMO98gOL4cmtAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDoQ6AEwAA#v=onepage&q=steve%20shapin%20never%20pure&f=false",
"http://books.google.co.uk/books?id=oa0aBTHQ_LIC&printsec=frontcover&dq=steve+shapin&hl=en&ei=I3zVTvzMD8u58gP9udWOAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDgQ6AEwAA#v=onepage&q=steve%20shapin&f=false"
],
[
"http://en.wikipedia.org/wiki/Republic_of_Letters"
],
[
"http://www.nybooks.com/articles/archives/2009/feb/12/google-the-future-of-books/?pagination=false"
],
[
"http://books.google.co.uk/books?id=QB3Ag08CdtwC&printsec=frontcover&dq=steve+shapin+never+pure&hl=en&ei=WH7VTo_qBMO98gOL4cmtAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDoQ6AEwAA#v=onepage&q=steve%20shapin%20never%20pure&f=false",
"http://books.google.co.uk/books?id=oa0aBTHQ_LIC&printsec=frontcover&dq=steve+shapin&hl=en&ei=I3zVTvzMD8u58gP9udWOAg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDgQ6AEwAA#v=onepage&q=steve%20shapin&f=false"
]
] |
|
ssw92
|
Can someone explain the validity of this claim? Using microwaved water vs. purified water to water your plants
|
Saw this on one of those facebook posts a thousand people liked/shared: _URL_1_
The caption:
> It has been known for some years that the problem with microwaved anything is not the radiation people used to worry about, it's how it corrupts the DNA in the food so the body can not recognize it.
> Microwaves don't work different ways on different substances. Whatever you put into the microwave suffers the same destructive process. Microwaves agitate the molecules to move faster and faster. This movement causes friction which denatures the original make-up of the substance. It results in destroyed vitamins, minerals, proteins and generates the new stuff called radiolytic compounds, things that are not found in nature.
> So the body wraps it in fat cells to protect itself from the dead food or it eliminates it fast. Think of all the Mothers heating up milk in these 'Safe' appliances. What about the nurse in Canada that warmed up blood for a transfusion patient and accidentally killed him when the blood went in dead. But the makers say it's safe. But proof is in the pictures of living plants dying!!!
Valid at all? Why is the plant labelled 'microwaved water only' as shown vs. the one that only received purified water? Also, why would anyone microwave water before watering their plants?
**EDIT**: This has been discussed multiple times. As early as [6 years ago](_URL_0_).
|
askscience
|
http://www.reddit.com/r/askscience/comments/ssw92/can_someone_explain_the_validity_of_this_claim/
|
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"Previously discussed: _URL_0_",
"To address the first paragraph of the claim, this describes ionizing radiation. Microwaves do not have enough energy to ionize substances. \n\nIf any nutrients are destroyed, it is due to heat and cooking time. The interesting thing is that microwaves use less heat than an oven, and have shorter cooking times, so things cooked in microwaves will retain most of their nutrients unlike things fried or sautéed, which will have a good bit of their nutrients destroyed.\n\nWatering plants with microwaved water (which I assume is allowed time to cool) should be no different than non microwaved water. Water is H2O no matter how many times you microwave. And there are no nutrients in water to be denatured even if microwaves could do that.\n\nAnother thing. They say radiolytic compounds are formed by radiation. This radiation does not refer to electromagnetic radiation, which is what microwaves emit, but radioactive decay. Microwaves will not produce radiolytic compounds.",
"I'm interested to hear more from an engineer, but from a quick wiki read of it it sounds pretty unfounded. I'd want to know more about the experiment. Was the water poured in hot? warm? room-temp? Where is the before picture? Was the microwaved water from the same source (purified)?\n\n[Wikipedia](_URL_0_)\n > Microwaves do not contain sufficient energy to chemically change substances by ionization, and so are an example of nonionizing radiation. The word \"radiation\" refers to energy radiating from a source and **not to radioactivity**.\n",
"Even if you're not a plant scientist, you can tell that the plant on the left has been cut :/"
]
}
|
[] |
[
"http://www.reddit.com/r/reddit.com/comments/4iz7/what_microwaved_water_does_to_plants/",
"http://i.imgur.com/6iFiI.jpg"
] |
[
[
"http://www.reddit.com/r/askscience/comments/qaary/a_girl_on_my_fb_posted_this_claim_about/"
],
[],
[
"http://en.wikipedia.org/wiki/Microwave#Health_effects"
],
[]
] |
|
2bez16
|
what happens to a wasp when i hit it with raid?
|
Also, I sprayed a small beetle at the same time as I sprayed a wasp just now, and the beetle took about 2-3 minutes to die while the wasp died in seconds. Any reason for that?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2bez16/eli5_what_happens_to_a_wasp_when_i_hit_it_with/
|
{
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"text": [
"You must have hit the wasp with RAID 0, which is why it worked so fast. RAID 1 was still effective on the beetle, it just didn't have the same level of performance (but was safer for you, incidentally). \n\n...I'm so sorry.",
"Insecticides are neurotoxins, they're the insect equivalent of satin of VX. They work by interfering with the operation of the insect's nervous system. In addition to the actual neurotoxins, insecticides will also include compounds that break down the insect's waxy coating, allowing the neurotoxins to enter more quickly and compounds that inhibit enzymes that would break down the neurotoxins, making the required amount tof neurotoxins smaller.\n\nWithout knowing the composition of the spray, it's difficult to say, but it's almost certain intentional. Spraying a wasp and having it die minutes later is not good, because that allows time for the wasp to attack you, while battles can't do that much. It could be that the wasp spray is more concentrated or contains a neurotoxin that is more effective on wasps or could be any number of variables in the formula. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
2korzl
|
why does netflix regularly remove movies instead of increasing the size of their library when adding new titles?
|
As you can see in this link, come Nov. 1st, Netflix is removing some great titles. So why, instead of increasing the list of available movies and dominating the industry, would they remove movies? ALL FOUR seasons of The Magic School Bus?? Heartless.
_URL_0_
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2korzl/eli5_why_does_netflix_regularly_remove_movies/
|
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"When Netflix buys the rights to distribute certain content they are ALWAYS time limited. Meaning, Netflix has the rights to a show like The Magic School Bus for a certain period of time. Once that time is over, Netflix must renegotiate the contract with whomever owns the rights to The Magic School Bus. \n\nIf it were fully Netflix's choice, I'm sure they would never remove content. but it's not. So most of the time this happens it's because the rights holder wanted more money than Netflix was willing to pay for the content. They could not come to an agreement so the old contract was allowed to expire. ",
"Netflix doesn't own the movies we see there it \"rents\" them from the companies who do, so they are removed when the contract is over. In most cases these are renewed when the contract is over, but not every time, and not immediately ",
"When Netflix \"gets\" a movie or show what is actually happening is they are buying a contract that grants them the privilege of showing it to their customers. Sometimes when the contract expires they do not re-negotiate so they are no longer allowed to air that show. ",
"Netflix pays for a license to provide a show for a set amount of time. So if for whatever reason they don't renew the license, they can no longer legally provide it. It's definitely annoying, as a parent with young kids, they lost Sesame Street just as my 3-year-old was starting to enjoy it.",
"They removed all of their Discovery channel content earlier this month (because Discovery wants to do their own streaming service). No Mythbusters (except for what ends up on youtube before being DMCA'd)"
]
}
|
[] |
[
"http://gothamist.com/2014/10/28/here_are_the_new_netflix_titles_str.php"
] |
[
[],
[],
[],
[],
[]
] |
|
jt07r
|
Zoo animals getting excited before earthquakes?
|
There was a notice from the National Zoo today about how the zoo animals responded to the earthquake. (If you're interested, you can find it here: [Link](_URL_0_))
Many of the animals acted like you'd expect - bothered by the earthquake, a bit ruffled for a while. But some started acting strangely *before* the earthquake. Some of the apes were bothered a few seconds ahead of time, the flamingos rushed around and huddled before the earthquake, and the lemurs sounded an alarm call minutes before.
What's the deal?
|
askscience
|
http://www.reddit.com/r/askscience/comments/jt07r/zoo_animals_getting_excited_before_earthquakes/
|
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"There are two things at work here. The first is for the events that happen mere seconds to a minute before the Earthquake hits. There are two types of waves that travel through the earth during an earthquake, p-waves and s-waves. P waves travel faster but are hard to detect, s-waves travel slower and are the ones that cause all the damage. Some animals are better at detecting these small p-wave vibrations than humans and they start freaking out because of it. \n\nNow, what about the animals that start freaking out hours before, or even a day before, the earthquake? Selection bias, pure and simple. Any given day in the zoos around the world, animals are going to start freaking out and acting strange for no apparent reason. However, no one really pays it any mind because animals do weird crap all the time. However, when they happen to do weird crap, and then an earthquake comes, people say \"oh yeah, I remember. The monkeys were all huddled in a corner yesterday, and they looked scared. And then today an earthquake came\" However, if the earthquake hadn't come, no one would have paid it any mind. ",
"There are two things at work here. The first is for the events that happen mere seconds to a minute before the Earthquake hits. There are two types of waves that travel through the earth during an earthquake, p-waves and s-waves. P waves travel faster but are hard to detect, s-waves travel slower and are the ones that cause all the damage. Some animals are better at detecting these small p-wave vibrations than humans and they start freaking out because of it. \n\nNow, what about the animals that start freaking out hours before, or even a day before, the earthquake? Selection bias, pure and simple. Any given day in the zoos around the world, animals are going to start freaking out and acting strange for no apparent reason. However, no one really pays it any mind because animals do weird crap all the time. However, when they happen to do weird crap, and then an earthquake comes, people say \"oh yeah, I remember. The monkeys were all huddled in a corner yesterday, and they looked scared. And then today an earthquake came\" However, if the earthquake hadn't come, no one would have paid it any mind. "
]
}
|
[] |
[
"http://nationalzoo.si.edu/Publications/PressMaterials/PressReleases/NZP/2011/earthquake.cfm"
] |
[
[],
[]
] |
|
2sdivn
|
When did Christendom forbid slavery? Did the church have anything to do with it? Were there any exceptions to the ban?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2sdivn/when_did_christendom_forbid_slavery_did_the/
|
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"text": [
"What exactly do you mean by Christendom forbidding slavery? Do you mean as in a bible verse, a decree from the Pope, or what? \n\nI'm asking because there are arguably pretty late instances of individual Christians practicing slavery (in the United States for example), and I don't know if they considered it to be forbidden at the time. ",
"I can only speak of Catholicism and slavery.\n\nThe first Pope to publicly condemn slavery was Benedict XIV in 1741. That being said, the church did not come down hard on slavery until Pius VII in the aftermath of the Napoleonic Wars.\n\nWell into the 16th century the Church publicly supported slavery. Pope Paul III authorized the purchase of Muslim slaves in 1548. \n\nFrom a religious standpoint, 1839 is generally considered the year the slavery was \"banned\" by the Catholic Church. Gregory XVI's *In Supremo Apostolatus* was a papal bull officially condemning slavery. It was followed by the Church working to end colonial slavery, most famously in Brazil."
]
}
|
[] |
[] |
[
[],
[]
] |
||
1kth1e
|
How can a person remain "themself" after undergoing a hemispherectomy?
|
I apologize if this is not an appropriate question for askscience. It might be more philosophical than scientific in nature.
My question is: How can a person retain "who they are", for lack of a better phrase, after having half their brain removed? You can remove the right side and the person is still there. Remove the left side and the person is still there. Remove both sides and clearly they are dead. Where do we store "ourself" if not in either side of the brain?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1kth1e/how_can_a_person_remain_themself_after_undergoing/
|
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"if you need a hemispherectomy, probably because of epilepsy, then that hemisphere is probably already very damaged, and much of its function has probably been taken up by the healthy hemisphere. and this is the real answer to the question; the cerebral cortex is very adaptable, especially early in life. if you lose a hemisphere early in life, you can attain surprisingly close-to-normal function in most domains. but if you lose a hemisphere late in life, and there was no long-term cause for reorganization (e.g. relative unusability of much of the lost hemisphere due to epilepsy), then you will have many, many problems: paralysis or paresis of half the body, blindness in half the visual field, problems with language, memory, attention, etc.\n\nif you're getting at a more philosophical question about the unity of consciousness - the sensation you have of being a thing, a self, with all this simultaneous access to sights and sounds and feelings and memories and volitions - there are good theories of how it works. my favorite is Giulio Tononi's \"[information integration theory] (_URL_0_)\", which says that consciousness corresponds to the subset of structures in the brain that are all informative about one another in a certain (mathematically-defined) way. two properly connected hemispheres (Tononi and most other researchers think that consciousness mostly subsists in the cerebral cortex, and disagree about which parts precisely are included) constitute a single, highly-complex, integrated structure that corresponds to your subjective consciousness or \"self\". if you remove a hemisphere, then the size of this structure decreases, but it is still integrated, and so the self remains. interestingly, if you leave both hemispheres alone but *cut* the connections between them, you can have a \"split brain\" patient, someone who effectively has two parallel consciousnesses, without access to one another but sharing the same body (and same sub-cortical brain structures).\n\nso there is science out there to get at your question, and it's really a hot topic these days, but the short answer boils down to.. we don't know but we have lots of good ideas."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Integrated_Information_Theory"
]
] |
|
uhodj
|
Circumstances surrounding the Death of Ludwig II of Bavaria
|
I was recently in Austria, attending a language school and we briefly covered the unification of Germany. We were told Ludwig II died mysteriously, perhaps to facilitate the unification. I've found little information on my own beyond conjecture. What conclusion does historical evidence support?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/uhodj/circumstances_surrounding_the_death_of_ludwig_ii/
|
{
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"text": [
"His death was quite mysterious and there are many conspiracy theories, but he died in 1886 and the unification was already accomplished in 1871."
]
}
|
[] |
[] |
[
[]
] |
|
6qkbd9
|
if frozen yogurt comes from cow dairy and ice cream comes from cow dairy, how is frozen yogurt "healthier"?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6qkbd9/elif_if_frozen_yogurt_comes_from_cow_dairy_and/
|
{
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"text": [
"It's not really. Yogurt is viewed as a healthy snack, so people assume frozen yogurt is healthy, when frozen yogurt is just as full of sugar as regular ice cream. ",
"Traditionally, yogurt is made with less fat than ice cream. That's really the only way in which it could be described as healthier."
]
}
|
[] |
[] |
[
[],
[]
] |
||
6dw9vx
|
as people get older, why does it become harder to consume large quantities of food in one sitting?
|
Maybe this isn't actually a thing, and if it is, it probably depends on the individual, but I know that, personally speaking, I used to be able to scarf down massive plates of food when I was a kid (probably a serious contribution to my current weight issues). But nowadays, eating as much food as I could as a child is damn near impossible, and I've met people who say the same. Is there actually a reason for this, or is it just a case of me coming to my senses as an adult?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6dw9vx/eli5_as_people_get_older_why_does_it_become/
|
{
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"It's not a hard and fast rule, although *appetite* tends to peak during and shortly after puberty. What can certainly alter your ability to eat a lot in one sitting would be obesity; you have less room for your internal organs, and that includes stomach and intestines. "
]
}
|
[] |
[] |
[
[]
] |
|
28mu4q
|
Why is 2^1024 the limit of so many web calculators?
|
I was using the Google built in calculator, as well as the Desmos graphing calculator and neither can calculate 21024. Both can calculate 21023 as well as 1.9999999999999991024, but if I were to add one more nine to the end or try 21024 both just give the answer infinity.Why is this? Is this because of the limit of the hardware the server is run on, or is it something else?
|
askscience
|
http://www.reddit.com/r/askscience/comments/28mu4q/why_is_21024_the_limit_of_so_many_web_calculators/
|
{
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"A limit has to be chosen, since we only have a certain number of bits at our disposal to represent a number. The choice is somewhat arbitrary.\n\nHowever, there are a few standard representations that are commonly used and implemented as low-level instructions within the FPU, so it's common to use one of them in order to make the calculations go faster.\n\na [double](_URL_0_) is the standard way of representing real numbers using 64 bits.\n\nYou have 1 bit of sign, 52 bits of \"data\" and 11 bits of exponent (1 for sign and 10 for value).\n\nUsing that representation, a number takes the form:\n\n +/- [0 1] * 2^[-2 ^ 10 2 ^ 10[ \n\nWhere [0 1] is quantized using 52 bits. \n\n2^10 is 1024, so the maximum representable value is \n\n 1 * 2 ^ ( 2 ^ 10 - 1 )\n\nwhich is 2 ^ 1023\n\n",
"Calculators such as the ones mentioned use a standard representation of numbers, specified by an [IEEE](_URL_0_) standard ([IEEE-754](_URL_2_)), that uses 64 bits (64 1s and 0s) to represent a value. This limits the total number of possible values, and thus the *range* of values, that may be represented.\n\nIf you are familiar with [scientific notation](_URL_1_), i.e. expressing a number using a *mantissa* and *exponent*, the format is relatively simple to describe. One of those bits indicates the sign of the number (0=positive, 1=negative), 11 of the bits are used to express the exponent (but in base 2, not 10), and the remaining 52 bits are used to express the mantissa.\n\nIt turns out that the largest possible value that can be represented exactly is just a little shy of 2^1024, or about 1.8x10^308... or more precisely:\n179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368.\n"
]
}
|
[] |
[] |
[
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"http://en.wikipedia.org/wiki/Double-precision_floating-point_format"
],
[
"http://www.ieee.org/index.html",
"http://en.wikipedia.org/wiki/Scientific_notation",
"http://en.wikipedia.org/wiki/IEEE_floating_point#Basic_formats"
]
] |
|
1o51gn
|
how come perfect eyesight is 20/20?
|
And how come the grade increases as eyesight capability decreases? Do they use the same system for nearsightedness and farsightedness?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1o51gn/eli5_how_come_perfect_eyesight_is_2020/
|
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"Eye doctors have decided what a \"normal\" human being should be able to see when standing 20 feet away from an eye chart. If you have 20/20 vision, it means that when you stand 20 feet away from the chart you can see what the \"normal\" or average human being can see. In other words, your vision is \"normal\" -- most people can see what you see at 20 feet. \n\nIf you have 20/40 vision, it means that when you stand 20 feet away from the chart you can see what a normal human can see when standing 40 feet from the chart. That is, if there is a normal person standing 40 feet away from the chart and you are standing only 20 feet away from it, you and the normal person can see the same detail. 20/100 means that when you stand 20 feet from the chart you can see what a normal person standing 100 feet away can see. 20/200 is the cutoff for legal blindness in the United States.\n\n\nSource\n_URL_0_",
"20/20 isn't perfect vision, it's average vision. What it essentially says is you can see something at 20 feet what the average person can see at 20 feet. \n\nIf you had, say, 200/20 vision, you would have amazing vision: you could see at 200 feet what the average person could see at 20.\n\nLikewise, if you had 20/200 vision, you'd have terrible vision, because you could only see something at 20 feet what the average person could see at 200 feet. ",
"great explanations from others, so I won't add much other than 20/20 can't be perfect since people have the capability of eyesight such as 20/15, which would be 'better' eyesight than someone with 20/20",
"It isn't perfect, it's normal.",
"Ophthalmologist here. \nFrom 20 feet, or 6 meters, the light rays entering the eye are essentially parallel. There is no need to accommodate (change the focusing power of the lens of the eye). That is why we use the 20/20, or 6/6. Light rays that are from a closer object would be diverging when they hit your eye, and would require focusing effort. Light rays from farther than 20 feet are indistinguishable from those 20 feet away.\n\nThe limit of human vision is calculated to be around 20/08. If you think of it in terms of pixels, the cone photoreceptors are packed most tightly in our fovea (center of our retina). If the rest of the eye were perfect, i.e. no cataract or refractive error, you could see 20/08. \n\nThose young adults who can read the 20/10 line without glasses have close to perfect vision.",
"20/10 Vision Master race reporting in. \n",
"I've got 20/10, pretty much double vision. The world to me is completely flat with no blurred vision of anything at any distance. From a personal standpoint I think its 'perfect vision' just because almost anyone with any other vision can't even see what I'm talking about or describing. You'd be surprised at how many people have terrible vision and can't even read fine print off the tv.\n\nEdit: For the down voters, I can walk back an extra 10 ft (30 ft total) and still read the bottom line of an eye chart. ",
"20/10 after lasik. Feels good man.",
"So if my right eye is -5.50 with contacts and my left eye is -3.50 what does that make me?? Other than blind as shit.",
"I think 20/20 actually means that you have normal / average vision.\n\nThe ratio means: You can see something at 20 feet away, that the average person would have to be 20 feet away to see.\n\nI can't remember which way round the ratio works, but say you were almost blind, your eyesight might be 20/200 for instance. This would mean:\n\nYou have to be 20 feet away from something that the average person can see at 200 feet away.\n\nThat means that you can also have eyesight that is better than 20/20. If you had 20/15, it would mean you could see something from 20 feet away that somebody has to be 15 feet away from.\n\nI may have gotten the ratio the wrong way round, but the principle is right I believe.",
"Just out of curiosity OP, did you listen to the JRE with bryan callen? I just listened to it on my run and thought to myself \"I am going to look up how 20/20 vision works when i get home\", and then this is the first reddit thread I see.",
"Maybe this is *slightly* above a \"five-year-old\" level, but I'm just adding info for anyone else interested.\n\nYou know the Snellen eye chart:\n\n E\n F P\n T O Z\n L P E D (etc...)\n\nThe letters above the red line, \"D E F P O T E C\" 8 lines down, that's 20/20, and each little branch of each letter (like the middle line of the E) is one second of arc, if you're standing 20 feet away.\n\nWhat's a second of arc? Well, you know if you look all around you, that's 360°? Each degree is broken up into 60 minutes, and each minute is broken up into 60 seconds. (For comparison, the Moon is about 900 seconds big).\n\nSo, the idea is that if you're seeing 20/20, if means you're able to see something as small as one second of arc. That's also why you can go \"under,\" like 20/15. It means you can see even smaller detail. If you are 20/25, that's still pretty \"clear\" vision. You can be up to 20/40 before the DMV says you needs glasses to drive.\n\n > \"Do they use the same system for nearsightedness and farsightedness?\"\n\nYes and no. For a farsighted person, we can put a miniaturized eye chart at the proper distance away from them (say 18 inches), and measure their visual acuity in terms of 20/20 (can the differentiate 1 second of arc from that distance). Although the whole \"twenty feet\" application doesn't fit, you would still describe a patient as having 20/20 acuity at 18 inches.",
"Optometrist here. This topic is confusing because people use the word \"perfect.\" 20/20 eyesight is not \"perfect\" vision. It is just what vision specialists have \"standardized\" as being normal. It is a useful convention for eye care specialists, because If you are seeing less than 20/20, there is almost always a reason (whether it be need for glasses, a problem with which you were born, or some disease process). Some people have better than 20/20- that is 20/15 or 20/10. The differences for these higher levels of vision can be accounted for with the size and density of the photoreceptor layer. In humans, this maximum ability appears to approach a limit around 20/08. You could call this \"perfect,\" but as soon as we create a way to more densely pack your photoreceptor layer, a new \"perfect\" will be created. Interesting fact, eagles crush human resolving ability as they see somewhere around 20/05. ",
"Hey, studying optometry at the moment in 3rd year. \n\n20/20 eyesight is a measurement of the smallest objects you can see. The first 20 stands for the distance you are reading the chart/object, where in America it's 20 feet but in Australia we call it 6/6 since it's 6 metres. The other 20 is used to describe the size of the letter, but it's essentially something to do with seconds of arc subtending over a 1m (if you have done trigonometry it's like the triangle with the 20 corresponding something with the angle [sorry I forgot about this part, might have to look into my notes about this]\n\nThe grade increases as eyesight capability decreases since as the second number gets bigger, something like 20/40, the letters get bigger. So if you are only able to resolve larger letter, obviously your vision is poorer.\n\nNearsightedness also known as myopia, is when you can't see things far away and Farsightedness, hyperopia is when you can't see things up close. Since 20/20 is an measurement of visual acuity, resolving power of your eyes it will be used for both. However your condition being nearsightedness or farsightedness will be noted by the type of lens you need for your spectacles, -ve lenses for myopia and +ve lenses for hyperopia.\n\nI would also like to note that 20/20, or 6/6 in Aus is the general standard of visual acuity that the average individual should have or be corrected to. So it's a standard optometrists follow to know if we are giving the correct prescription. It's not especially good vision or anything special, just a norm we use. It can be seen that some people have better than 20/20 vision, like 20/10 which are a small percentage of the population but isn't that strange since there are fluctuations in almost everything\n\nHope this clears this up for you,\n\nCheers. ",
"If I have -5.00 on each eye, what would that make me? The different systems confuse me",
"When my son finally got glasses in fourth grade, he said he had no idea that people could actually see farther than 3 feet away from them. I felt like the worst mom ever.",
"What does -5.25 for both eyes for contacts what does that make me and can I get laser eye surgery for that? I'm 18 btw.",
"Well, look at the ratio.\n\n20/20 = 1 = normal\n20/40 = 1/2 = 0.5 = your vision is worse than normal.\n20/10 = 2 = really good - you see twice the detail of a normal person.\n",
"20/20 means \"you can see at 20 feet what a normal person can see at 20 feet.\"\n\n20/20 is not \"perfect,\" but \"normal\". \n\nThe value 20 is arbitrary, though probably based on the practical dimensions of optometrists' offices.\n\n20/10 is actually better than normal. 20/1 would be astronomically good.\n\nNearsightedness is indicated by the numerator being less than the denominator. 20/40 means you must be 20 feet distance to see what most people can see from 40 feet, therefore, \"near\"sighted. Meanwhile, a numerator higher than the denominator, e.g. 20/10, means you can see at 20 feet what most people see at 10 feet (the implication being that you can't see it at 20 feet), therefore \"far\"sighted.\n\nAn eye exam starts from the expectation that you (that is to say, your eyes) are 20 feet away from the chart, and should be able to read everything from the 20/200 line to the 20/20 line. If you can't read the 20/20 line from 20 feet, but you can read the 15/20 line, you're nearsighted.\n\nOn the other hand, if you can see from 20 feet what most people can see at 15 feet, but *cannot* see at 20 feet what most people can see at 20 feet, you have 20/15, which is farsightedness. The idea here is that the number you get is the closest you can get to 20/20. If you can see 20/20 *and* 20/15, then you have better than normal vision.",
"Actually, 20/10 vision is perfect vision. I have 20/15 vision.",
"Personally, my hindsight is 20/10",
"Human visual acuity follows a bell curve. The curve is shifted past 20/20 however. Most people think that 20/20 is perfect vision. 20/20 is the norm that we look for, otherwise we look for an explanation for the decreased vision. People can see much better than 20/20 though. Many younger people, if not most are capable of 20/15 (which is effectively an ability to an object at 15 feet where someone who is 20/20 could only see the same object at 20 feet). There are also some, but fewer people cable of seeing 20/10 or even 20/8.\n\nThe above is all in reference to with an optical correction (glasses or contacts for example). Without it, then people's vision is much more all over the place. Several factors come into play when looking at the best vision possible. First is the optical correction above. Next is to make sure the neurological connections are capable of good vision. eg. Amblyopia is when the eye itself is healthy, but the neurological connections never developed for one of several reasons, so the person is not capable of 20/20. The next is how tightly packed the photoreceptors are in the eye. The closer the spacing, the more capable that eye is holding all other factors equal.\n",
"Its not perfect. I have 20/15 vision. \nWhat normal people see at 15 feet. I can see at 20. \n",
"that's not perfect, it's normal."
]
}
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[] |
[] |
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|
5jrty1
|
does earth appear as a bright planet?
|
Since Earth has a lot of water to reflect light, does it appear really bright from far away compared to other planets? If a telescope looked at our solar system from a few million light years away would they easily see Earth?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5jrty1/eli5does_earth_appear_as_a_bright_planet/
|
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"[Here is a picture and a speech](_URL_0_). The answer is no - the earth is not particularly luminous. No more than the other planets in our solar system. You lose sight of us before you leave the solar system. Long before then, we're nothing but a pale blue dot.",
"A few million light years away? That is an insane distance. Our entire galaxy is only ~100,000 light years in diameter. Even one lightyear away would be too far, not only is our planet not that bright, it is minuscule in comparison to the sun so anyone trying to look for us would just see our big, bright sun. This is a struggle we have in our search for planets outside of our solar system, no telescope is powerful enough to see them, however we are able to detect them by other methods."
]
}
|
[] |
[] |
[
[
"https://www.youtube.com/watch?v=p86BPM1GV8M"
],
[]
] |
|
7coqv6
|
thinking about probability, how is it possible that one and only puzzle piece fits in another in a jigsaw puzzle?
|
A "difficult" jigsaw puzzle has, say, 1,000 pieces, each made the same way - circles and holes for circles. It's interesting to me that each piece has one and only one other piece that it works with, given that there are 998 other pieces in the set that look almost exactly like it but don't quite fit.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7coqv6/eli5_thinking_about_probability_how_is_it/
|
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"text": [
"That's not probability that's design. Jig saw puzzles arent random. Someone actually sat down and drew out the lines specifically so that they only fit one place.",
"If you have a discrete probability space, then you would have a non-zero chance that two or more pieces would be the same, but when you have a continuous probability space (like the shape of all jigsaw knobs), then the chances that two random pieces would have the same knob shape is zero. \n\nprecisely, the subset of all similar pieces has measure zero in the probability space. To break down that jargon a bit: what is the length of a point on a line? Zero. What is the length of two points on a line? Also zero. If we make that idea more precise (which is not easy, and outside the scope of this comment, but this is what I mean by \"measure\"), we can have an infinite number of points whose length is zero. For example: rational numbers between 0 and 1. Now, the interval from 0 to 1 has length 1 (we haven't gone that crazy), but the \"length\" of all rational points added up is still zero. That's a set of measure zero.\n\nOf course, things get more complicated when you allow for tolerances. What defines fit? How far off do those shapes need to be before they don't fit?",
"A puzzle isn't really a good example, since a piece is obviously wrong if the details on that piece don't make the details of its neighbors.\n\nImagine a picture of a rainbow. You're not going to try and fit a blue piece in the red band. It *may* fit there, but it doesn't *belong* there.\n\nThere really aren't that many different shapes for the pieces. The number of images on the pieces can be anything you want, but a manufacturer is going to have a limited number of dies that cut out the shapes.\n\nA \"truly\" difficult puzzle would be a 5,000-piece puzzle, and each piece is a the same solid color.",
"The inserts and the holes are each unique. \n\nAnd while some prices can fit within a certain tolerances they are not the perfect fit. It's actually fairly common for pieces to be able to be set together so that not \"one and only one\" piece fits into another - but here you might have to \"force\" the two together. \n\nFurthermore, perhaps two pieces do match identically, that is only 1 of 4 sides, so would their intended boarder pieces also match so that 4 or 6 of the two sets would still match? Afterall, each piece has 4 sides of its own. And then each boarder piece will have its own boarder pieces and so on. \n\nEven furthermore, each puzzle is limited to a set number of pieces. In a 10,000 piece puzzle, your chances of finding a perfect fit between two unintentionally fitting pieces is higher than in a 100 piece puzzle. \n\nBut in terms of \"possibility\" so that \"one and only one piece\" could fit perfectly, one would need to make a computer algorithm to adjust the size and shape of each piece. Then a wire electronic discharge machine could easily cut some metal pieces that have tolerances well under half of a millimeter, meaning the variance between pieces only need to scale by the tolerances. Easily and realistically done. \n\nBut since most puzzles are paper products, we can't have this precision. "
]
}
|
[] |
[] |
[
[],
[],
[],
[]
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|
2gyceu
|
How did Mohammed and his followers--and, for that matter, his immediate predecessors and fellow Arab people of the time--come to believe in a bunch of the same stuff as the Jews did?
|
I guess I've sort of taken for granted that Christianity, Judaism, and Islam are the "Abrahamic faiths." Recently, though, out of curiosity, I decided to sit down and read the Koran, and as I sat there scanning through the Adam and Eve story, or reading something about Moses, it struck me that I had no idea how these common elements of belief ended up in Arabia anyway--how did this guy in 7th century Arabia, who wasn't a Jew, come to believe this stuff?
Certainly, I know enough to know that Islam didn't grow out of Judaism as, say, Christianity did, but evidently, pre-Islamic Arabs shared a lot with them. How much do we know about Pre-Islamic Arabian religion? Is there some specific name for the religion that Mohammed was born into? In addition to the populations of outright Christians and Jews there, were there particular groups that were more "Abrahamic" and those that were more "pagan?" I know that a lot of Islamic religious practice had something to do with what was already there--the locals had been performing rites around the Ka'aba, albeit very different ones, for instance, but how "Abrahamic" were those folks? How and when did Abrahamic beliefs get to the area?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2gyceu/how_did_mohammed_and_his_followersand_for_that/
|
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"text": [
"You may also be interested in reading some of the answers in this fairly recent [AMA on Pre-Islamic Arabia](_URL_0_).",
"I asked a very similar [question](_URL_0_) recently, that received some informative responses.",
"Pre-Islamic Arabia was a mix of a few religions at this time. The main religions in this region were Judaism, Christianity, and a form of Pagan tribal religion. While there is some evidence to suggest that some of the Pagan people believed that there was only one God, most believed in multiple deities and had a personal/family deity that that individually worshipped. Overall the Pagan people were non-Abrahamic and polytheistic. Other traits of theirs would be incorporated into Islam but not their polytheistic traditions.\n\nWhen you examine early Islam it is important to remember that Muhammed saw himself as worshipping the same God as Jews and Christians but that they had gone astray and God talked to him to show these people how they had gone astray. The reason why you see many similarities with Judaism and Christianity is that Islam believes that these religions were founded by the same God that talked to Muhammed."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/AskHistorians/comments/28n21d/ama_preislamic_arabia/"
],
[
"http://www.reddit.com/r/AskHistorians/comments/2b423q/why_did_islam_model_itself_after_judaism_what/"
],
[]
] |
|
7d1xda
|
if carbon dioxide is bad for you to inhale, and people provide it when you breath out, wouldn't the carbon dioxide do any damage to the person getting mouth to mouth?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7d1xda/eli5_if_carbon_dioxide_is_bad_for_you_to_inhale/
|
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"It's not enough to cause harm. Your exhaled air is still quite high in oxygen, and is *much* better for the other person than no breathing.",
"Carbon dioxide doesn't hurt you. A lack of oxygen hurts you, and carbon monoxide hurts you.\n\nYou don't convert all the oxygen you inhale into carbon dioxide, so CPR is still effective. However, these days, heartsaver CPR is recommended (unless you have special training and two people). This uses the chest compressions to move some air through the lungs while also working the heart. It doesn't involve breathing into the person's lungs.",
"Pure carbon dioxide would be bad to inhale, especially for a prolonged time. OTOH, if a person is not breathing, the air you exhale contains carbon dioxide but it also contains some oxygen, which is good. So, some oxygen is better than no oxygen (i.e., no air at all - they're not breathing). If you could arrange to blow ordinary air (or even oxygen enriched air) instead of what you are exhaling, that would be better, but probably would require a hospital or some such. So, net, net, using your exhaled breath is better than nothing. Still, when they can breathe on their own, let them.\n\nBTW, pure nitrogen, pure laughing gas, pure helium, are all unsustainable for breathing. But you can do them for a bit. In the case of helium, folks do it since their voice sounds strange."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
kllzy
|
Theory
|
I get told quite often that Evolution is just a theory. (Should I capitalize 'evolution'?)
My response is usually something like...
"You're thinking of the wrong use of the word 'theory'. A *scientific* theory means that it has been tested and proven without fail MANY times. To put it in perspective...gravity is a theory." And if I have a cheap object available, I push it to the ground.
Is there anything I'm saying that's just blatantly false? I don't want to be wrong :/
|
askscience
|
http://www.reddit.com/r/askscience/comments/kllzy/theory/
|
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" > A scientific theory means that it has been tested and *proven* without fail MANY times.\n\nThis is incorrect - theories are never *proven*. They can only be accepted or rejected based on an ever-growing (hopefully) pile of evidence. It would be more accurate to say that an accepted theory has been tested and scientists recognize that it has passed all tests so far.\n\nGravity itself is not a theory but an observed force; our current *understanding* of that force, including the equations we use to describe our observations, is a theory.",
"To be fair, a theory just needs to be falsifiable. It doesn't need to be \"tested and proven without fail.\" A _bad_ theory is still a theory by virtue of scientific rigor and logical validity.\n\nEvolution just happens to be a _good_ theory - as with most well-known theories.",
"See the links [here](_URL_0_). Great synopses of theory, hypothesis, etc.\n\n",
" > A scientific theory means that it has been tested and *proven* without fail MANY times.\n\nThis is incorrect - theories are never *proven*. They can only be accepted or rejected based on an ever-growing (hopefully) pile of evidence. It would be more accurate to say that an accepted theory has been tested and scientists recognize that it has passed all tests so far.\n\nGravity itself is not a theory but an observed force; our current *understanding* of that force, including the equations we use to describe our observations, is a theory.",
"To be fair, a theory just needs to be falsifiable. It doesn't need to be \"tested and proven without fail.\" A _bad_ theory is still a theory by virtue of scientific rigor and logical validity.\n\nEvolution just happens to be a _good_ theory - as with most well-known theories.",
"See the links [here](_URL_0_). Great synopses of theory, hypothesis, etc.\n\n"
]
}
|
[] |
[] |
[
[],
[],
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"http://www.reddit.com/r/askscience/comments/kj1tk/what_is_the_difference_between_a_hypothesis_a/c2knyao"
],
[],
[],
[
"http://www.reddit.com/r/askscience/comments/kj1tk/what_is_the_difference_between_a_hypothesis_a/c2knyao"
]
] |
|
gafqa
|
Is there any science behind why elderly people often die close to the death of their significant other? It also seems to happen frequently with pets.
|
I have heard of many people and know many personally who have had grandparents and pets that once one passes away the other goes within days weeks or months, is there any science behind this?
|
askscience
|
http://www.reddit.com/r/askscience/comments/gafqa/is_there_any_science_behind_why_elderly_people/
|
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"text": [
"increased stress and depression in the immediate period after\n\nhere's one showing heart problems associated with bereavement [link](_URL_1_)\n\nEdit: heres a [link](_URL_0_) to the original infamous Finnish study",
"I work in a hospital and I've seen numerous people come in for various procedures, some mundane procedures some for some serious work. Sometimes people will arrive with a pessimistic view, I've heard a few patients say \"I'm going to die\". These patients have an **overwhelmingly** worse time recovering, not just in terms of healing but in things like sepsis, how their body handles infection. The placebo effect is real, there is actual science there. I would bet there are numerous reasons why elderly people die at a higher rate after their partner has passed on (Less pressure to survive, changes in lifestyle, no one to help with challenges, etc) but I think that a good portion of it has to do with the mind directly effecting the persons health."
]
}
|
[] |
[] |
[
[
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1380614/",
"http://esciencenews.com/articles/2010/11/14/death.spouse.child.may.cause.higher.heart.rate.other.dangers"
],
[]
] |
|
r035l
|
What is "chemistry" between two people actually? What is the logical explaination? Why is it so instant?
|
Like when two people meet they instantly feel connected but sometimes you meet attractive partners but you never "click". Why is that?
**EDIT** Also, why do you love this person instead of someone else? Why is this person more attractive? You never logically go for the most attractive guy/girl in the room... But something about them draws you in...
|
askscience
|
http://www.reddit.com/r/askscience/comments/r035l/what_is_chemistry_between_two_people_actually/
|
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"text": [
"It was thought for a while that there may be some kind of pheromone exchange responsible for this effect. That idea has been largely dismissed though as no Vomeronasal organ which would be sensative to such pheromones has been identified on adults even though some fetuses have been thought to show the organ. Even in it did appear in adults however there is no evidence that human beings have active sensory neurons like those in working vomeronasal systems of other animals. \n\nThe current discussion on the subject generally involves the principles of and the basic physiology behind interpersonal relationships. Most papers I've read on the subject tend to take it to the idea of like attracts like. [According to some evolutionary psychologists](_URL_0_) we select for a mate simply by scanning the environment and quickly filtering out those deemed unworthy, including those that are considered by us to be unattractive. From those not filtered out we select a potential mate. Love in this case is simply a transitory physiological experience caused when the body excretes epinephrine, dopamine, phenylethylamine, and other endorphins into our bloodstream.\n\nIn short there is no \"chemistry\" between you really, but there is a large amount within yourself as a kind of psychological response.",
"The sweaty t-shirt experiment. Girls seemed to be more attracted to sweaty t-shirts from males with the most diverse HLA molecules from their own. HLAs, or their mouse equivalent MHCs, are molecules that present antigen from cells to the immune system, mainly helper T-cells. The theory is that the most divergent HLAs serve best to promote variance during mating, thus creating immunologically \"strong\" offspring. \n\nEdit: [Here](_URL_0_) is more information on the study.",
"Your brain is very, very complicated. It does a lot of stuff unconsciously and then only tells you the result. Anything which is important to survival or reproduction is going to have massive evolutionary pressure to be as efficient as possible, and mate choice is obviously super important to reproduction, so the brain regions associated with mate evaluation are big, complicated, and fast. The 'chemistry' is just your brain going through a very large calculation (which includes an estimate of current or potential reciprocal attraction) and then says \"HEY LOOK AT HER!\"\n\nAs to why you identify the most attractive person in the room but then are not attracted to them, that's probably partially due to game theory concerns. Humans don't just need to find a mate, they generally want to keep their mate. It's therefore important to consider both how attractive that person is in general, how attractive they are to you, and how attractive they are relative to how attractive you are. If someone is waaaay more desirable as a mate than you, the relationship is unlikely to be stable (they won't give you the time of day or they'll dump you when something better comes along). IE, most guys don't have a chance with the hottest girl in the room. \n\nHowever, that's a rating of general attractiveness, based on generic tastes, and not everyone has the same tastes. Maybe you really like blondes, or maybe your brain smells the person and notes that you have very different Major Histocompatibility Complexes (having two different MHCs in your kids gives them much better disease resistance, so people with different MHCs tend to like each other's smells). If someone is unusually suited to your particular tastes, then they are a very good mate, because they are comparatively more desirable to you and thus a better mate than someone who is generically attractive. Your brain can do these sorts of estimates almost instantly as well.\n\nYou also want a mate who is interested in you (more efficient than chasing girls who won't give you the time of day). So, your brain also estimates a girl's interest in you. In the case where they are more attractive to you than they are in general, and where they're unusually interested in you for how attractive they are (implying you're more attractive to them than you are in general), your brain puts all those together and starts screaming at you. That causes you to show interest, which their brain notices and ups your attractiveness again, causing them to show interest, in a positive feedback loop. \n\nAnd this can all occur ridiculously fast, unconsciously, based on a large list of factors/criteria, with you only being aware of the result of the calculations, which results in the feeling of chemistry.",
"When my wife and I met it was instant love and ever since that day (10 Years) whenever I am around her I instantly feel so much happier. I recently had a bought of PST and depression and the only time of the day I felt OK was when I was touching or close to her. Even when I am normal, if she is gone too long I start to feel different and painfully miss her. I swear she is like a natural drug for me. \non the pheromone exchange aspect discussed elsewhere, I think it may/ have something to /do with the fact I am Irish and /she is Korean and studies show that the more genetically diverse someone's pheromones are, the more a individual is attracted to that person. Not the study I was thinking of but this is good enough: _URL_0_\n\n"
]
}
|
[] |
[] |
[
[
"http://www.epjournal.net/wp-content/uploads/ep02177194.pdf"
],
[
"http://www.pbs.org/wgbh/evolution/library/01/6/l_016_08.html"
],
[],
[
"http://www.youtube.com/watch?v=pEmX8Rim-hs"
]
] |
|
8zmn0a
|
what is chemotherapy, and what happens during it?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8zmn0a/eli5_what_is_chemotherapy_and_what_happens_during/
|
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"The elimination of fast cell reproduction. \nHair cells grow at a quick rate and is the reason why your hair falls out as well. ",
"It kills a LOT of cells in the body. As another comment mentions, it effects fast-growing or fast *reproducing* cells the most. Cancer is cells reproducing quickly (out of control), so it kills cancer cells.\n\nHair is affected which is the most visible side-effect. The digestive system also has cells that are quickly/often replaced so that's affected too. Skin can become irritated or more susceptible to injury.\n\nIt's basically nasty poison which badly harms or kills people. The idea is that it kills the cancer first. ",
"it's chemical treatment to combat (usually) cancer growth. most are in liquid form and are administered intravenously (through a drip in your arm). a single treatment of chemo may involve receiving several different chemicals in one session, commonly over quite a while (an hour or more). usually you sit on the ward with others while receiving it or there are some you can receive at home. depending on the length of course this may be done weekly or fortnightly for several months. on ward most people chat / read / watch tv while receiving treatment. the combination of chemicals are designed to slow down cell reproduction in your body. others are designed to kill cancer cells or types of cell in your body. there are lots of different kinds of chemo for lots of different kinds of cancer. the side effects usually stem from the slowing cell growth and killing of certain cells : hair loss, nausea/vomiting, constipation, thirst and so on. it's common to have additional courses of medicine that combat the side effects specifically.",
"Chemotherapy involves giving you drugs that inhibit DNA replication. If the DNA of a cell cannot replicate, the cell cannot divide. Do this to enough cells and the cancer growth can be significantly slowed or even stopped.\n\nChemotherapy drugs sometimes target the DNA directly. They might alter the chemical structure of the DNA so it can't be unwound. Or they might block the end of a growing DNA chain so it can't grow any further.\n\nSometimes the drugs target the enzymes involved in DNA replication. If the enzymes can't even attach to the DNA in the first place, or are altered so that they don't work properly, then no replication can take place. \n\nIf you are targeting cell division, then it makes sense that cells which divide quickly are the ones most heavily targeted. Cancer cells grow and divide quickly, which is why chemotherapy does more damage to cancer cells than to most of our 'normal' cells. However, a few types of 'normal' cells do actually grow very quickly, and so chemotherapy will sometimes accidentally target them too. These cells include:\n\nBlood cells: which is why anemia and immune suppression are common side effects.\n\nCells of the stomach lining and digestive system: which is why vomiting, diarrhoea, and nausea are common side effects.\n\nHair cells: which is why hair thinning and loss is a common side effect.\n\n",
"chemotherapy is like nuking your own body (literally nuking?) in an attempt to kill cancer cells faster than you. it can work.\n\nsometimes they kill all the cancer cells (as well as doing lots of damage to your human tissue) and you are cured. sometimes they kill all the noticeable cancer cells. in which case the cancer remains and reproduces again, but this time it is much more resistant to chemotherapy (because the only cells that survived are the ones that can survive lots of radiation).\n\nsometimes they don't even shrink the cancer but just slow its growth a little."
]
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|
[] |
[] |
[
[],
[],
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[],
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||
2b031v
|
How was honey harvested in ancient times? Were bees kept like they are today or was all honey harvested from the wild?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2b031v/how_was_honey_harvested_in_ancient_times_were/
|
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"hi! Could you specify which region/culture you're interested in - e.g. Greece, Nepal, the Maya, etc. That will help the appropriate historian(s) provide a meaningful response. Thanks!",
"Bees were kept, but not like today. Today, bees are kept in movable-comb beehives, which enables harvesting the honey without harming the bee colony. In ancient times, bees were kept in immovable-comb beehives, which were simply appropriately-sized vessels where the bees would build they comb naturally, and harvesting the honey would often mean destruction of the entire colony.\n\nAlso, before honey extractors were invented, people would eat comb honey, or honey would be pressed out from the comb."
]
}
|
[] |
[] |
[
[],
[]
] |
||
flxqj0
|
how can plants turn sun and water (and dirt) into wood, leavies and pretty much anything they need?
|
Inspired by the cow post.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/flxqj0/eli5_how_can_plants_turn_sun_and_water_and_dirt/
|
{
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"text": [
"You are actually missing out a critical part: air\n\nYes, most of a mass a plant actually comes from carbon dioxide within the air. They can convert it into plants with the Calvin cycle, which is a cycle made up of several chemical reactions that takes in carbon dioxide and converts it into glucose, which is essentially sugar\n\nThe energy to do this comes from the sun, chloroplasts receive solar energy and store it to be used for the Calvin cycle \n\nLots of molecules of glucose can then be chained together in order to form more complex molecules like cellulose that makes up most plants",
"The air is full of CO2, Carbon Dioxide. The ground is full of water.\n\nPlants use the energy of the sun to strip the Oxygen atoms and replace them with hydrogen from Water. This creates sugars (C6H12O6). \n\n6 molecules of CO2 + 6 Molecules of H2O = 1 sugar and leaves 3 Oxygen molecules (O2).\n\nOnce the plant has sugars it has energy the same way we do. Instead of changing sugars to fats the way animals do for storage it can also change them to starches. Starches are chains of sugars usually stored in roots, or seeds for the new plant to get started.\n\nPlants also need Nitrogen, Phosphorous and Potassium. Farmers sometimes add this through fertilizer, but these and other minerals are common in soil and absorbed by the roots. \n\nPlants have a very strong cell wall with very tight bonds between them for stability. They do this with either rigid walls or high internal water pressure. You can tell the difference by what happens when you take away the water. The plant either stays rigid or it wilts. Rigidity is done with wood or at the cellular level, Lignin. \n\nLignin is made up of the same types of atoms as sugars, but instead of being easy to take apart, the molecules are big and bind tightly together. \n\nThe cells that form wood are also very long fibers like our muscles, except the plant grows these cells with the intent that they die every year leaving another layer around the branch of the plant so it can support itself getting bigger and longer next year."
]
}
|
[] |
[] |
[
[],
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|
61gsol
|
welfare and food stamps
|
What are they, who can apply for them, and what exactly do they provide? I've heard the term thrown around, but what does it actually mean?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/61gsol/elif_welfare_and_food_stamps/
|
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"Welfare is sometimes called TANF or temporary assistance for needy families. Those who fall under federal guidelines for poverty may apply and are given money for rent, bills and other necessities. Typically, there is a work requirement and the recipient must comply to continue to be eligible. Food stamps are similar although the money can only be used for food. There is usually a misconception that people that receive the benefits are lazy but many have jobs and use these programs to stay afloat so to speak.",
"Anyone can apply for government assistance(welfare/foodstamps), but I assume you mean who can actually receive them. In many cases, if you can't get one form of assistance, you an get some other form of assistance. There are other forms of assistance not typically associated with welfare and foodstamps, like disability benefits, that serve a similar role but require medical examination.\n\nFor SNAP(food stamps) in my state you need to make less than 15k a year as a single person with no dependents. My family of 5 could get these benefits making less than 36k. The amount you receive scales on income and dependents, here's the WA state calculator.\n_URL_0_\n\nWelfare is broader and can cover things like heating during winter, rent, emergency housing for people displaced by abusive households, and many other services. All these are needs based and can for some people provide too little benefit to offset the effort in maintaining the flow of information to these various groups to continue gaining these benefits.\n\nThere are also some really niche ones that are mostly the gov helping itself, such as paying people to live in rural areas rather than congesting cities.\n\nShort answer: people that have dependents, make little money, live in undesirable locations, are at risk of harm due to environment, or are incapable of helping themselves."
]
}
|
[] |
[] |
[
[],
[
"http://foodhelp.wa.gov/bf_benefit_estimator.htm"
]
] |
|
sr6hn
|
What is a good book to read that will give me a survey history of modern European history?
|
I'm a high school student who took a European history class this year and fell in love with it. We have class readings from one book, but I want to read a different book this summer without having to analyze it and the like. Any suggestions?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/sr6hn/what_is_a_good_book_to_read_that_will_give_me_a/
|
{
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"text": [
"The trouble is that there are very few survey histories which aren't textbooks. The only one I can think of off the top of my head is [A Concise History of Modern Europe](_URL_1_), but I can't vouch for its quality since I haven't actually read it myself (one of my friends did).\n\nMy history classes often use readers from the [Bedford Series of History & Culture](_URL_0_) - they have a lot of selected documents from the period and varying amounts of commentary about the events. You can usually find them on Amazon, and they're really, really cool if you're into primary documents.\n\nIf you'd like recommendations for any specific periods in modern Europe, though, I'm happy to help! And also, your username has me intrigued.",
"[Postwar](_URL_0_), by Tony Judt, is the definitive guide to Europe after 1945. It's over 900 pages, but he has a wonderfully readable and sometimes entertaining style. I can't recommend it enough... even if you don't read every page, it will definitely keep you interested in history. \n\n",
"Robert Palmer's *A History of the Modern World* is an old classic which is not especially textbook-ish, though night-hawks is absolutely right that any survey of so broad a topic will be more textbook than not. You're better off, I think, finding more specific topics an getting into them more deeply. Wikipedia can fill in the big picture stuff as well as anything.",
"Mark Mazower's [Dark Continent](_URL_0_) provides a very unique look at European history, it is a bit dry in places, but overall I found it incredibly stimulating. ",
"*Europe: A History* by Norman Davies is a very good overview, although it's quite long. And I second the suggestion of *Dark Continent*."
]
}
|
[] |
[] |
[
[
"http://www.bedfordstmartins.com/Catalog/discipline/History/TheBedfordSeriesinHistoryCulture/European",
"http://www.amazon.com/Concise-History-Modern-Europe-Solidarity/dp/1442205342/ref=sr_1_5?s=books&ie=UTF8&qid=1335329025&sr=1-5"
],
[
"http://www.amazon.com/Postwar-History-Europe-Since-1945/dp/0143037757/ref=sr_1_1?ie=UTF8&qid=1335330834&sr=8-1"
],
[],
[
"http://www.amazon.com/Dark-Continent-Europes-Twentieth-Century/dp/067975704X"
],
[]
] |
|
dlj8bw
|
why are some atoms "easier" to become ions than others?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/dlj8bw/eli5_why_are_some_atoms_easier_to_become_ions/
|
{
"a_id": [
"f4qqspb",
"f4qsub4"
],
"score": [
6,
2
],
"text": [
"Because of their Electronegativity (hope thats the right translation) and their size. The Electronegativity basically is a force (Noted in the Periodic table) which defines how strong they are able to \"suck\" other electrons to themselves.",
"Ionizing an atom is adding or removing electrons. The position of the electron you want to add or remove is very important. Electrons are arranged in an odd way similar to seats in a movie theater. The front row has 2, the second third and fourth row have 8 which are partitioned into sets of 2 and 4, and as you go down the periodic table you add more partitions. The ionization energy depends on which seat you're trying to add or remove an electron from."
]
}
|
[] |
[] |
[
[],
[]
] |
||
3squye
|
what's the difference between a $10 bottle of wine compared to a $100 bottle?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3squye/eli5_whats_the_difference_between_a_10_bottle_of/
|
{
"a_id": [
"cwznfu5",
"cwznp4e",
"cwzofu0"
],
"score": [
6,
3,
2
],
"text": [
"A person who has developed the palette for it could tell the difference, and appreciate it. \nI think the subtleties of the $100 bottle would be lost on me, but I have tasted some $30/bottle wines, and they have been far richer and better-tasting than the $10 ones.",
"There are four different issues in wine pricing.\n\nDifferent people like different things about wine. Some people like a specific set of flavors that you can really only find in wine, and other people like wine that is, #1, very sweet and #2, alcoholic (yay booze). It's very easy to make grape juice ferment into a sweet alcoholic beverage but very difficult to make it produce those special flavors. As a result, the wines that produce the special flavors are much more expensive.\n\nSecond, even people who know what they are doing (kind of) can't get grapes that will make nice wine every year. Most fancy vineyards will sell thousands of gallons of bad wine at rock-bottom prices to wine factories every year. The owners taste what they have to work with, decide that it's not up to their standards and selling it will damage their brand, and sell it to a factory which mixes it with bad wine from a million other vineyards to produce a nice, generic, sweet wine that is inexpensive.\n\nThird, while you judge the quality of the wine early on from the tannins in it, you continue to age it in the bottle. Every year you age a wine, you have to raise the price proportionately to account for the rate of return you need on your investment, the cost of storage (you can't just chuck it in a cardboard box in a back room like at the local liquor room), and the fact that the longer you age it, the more bottles will be lost due to storage problems.\n\nFourth, buying wine is a little complicated. It's hard to store and expensive to ship. That makes it relatively easy for retailers to charge a markup, and for restaurants to charge a huge markup.",
"You are paying for particular flavors and other qualities that you expect of the particular region, grape or style. The biggest houses have their signature styles. \n\nBecause they have particular styles, they might not be quite what you wanted or expected so price is not a good indicator of what you're going to like. My recommendation is to start off cheap. Once you figure out a broad category of wines (red/white, dry/sweet, fresh/aged) you can explore slightly more expensive wines in that category. There are lots of great wines at almost every price range. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
84slxr
|
animal pain, human pain
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/84slxr/eli5_animal_pain_human_pain/
|
{
"a_id": [
"dvs22m2",
"dvs23x6",
"dvs26ox"
],
"score": [
7,
5,
3
],
"text": [
"Other mammals experience pain pretty much as humans do. But they don't have language or facial expressions to describe their suffering. And they need to get up and walk away, if the alternative is to sit around forever and die. No paramedic or doctor is coming.",
"Adrenaline.\n\nSame reason people can walk away from a car crash or a fall and not realize they've broken something right away.",
"Humans are definitely capable of this behavior. You don't go anywhere or do anything when injured if you are in safety, but people who suffer serious injuries don't just wait around if their stranded away from safety. Your survival instict tells you to relax and rest if you have food and shelter while injured, but if you don't have food and shelter your survival instict tells you to ***get off your ass and find some or die***."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
10yjhm
|
Who were the great administrators?
|
In my own studies of history I mostly focus on the more military aspects (it's just exciting), but I'm also interested on who were the innovative policy makers and economists of the world.
Now I'm cool with any suggestions but I do personally prefer more ancient to medieval time period.
So who do you guys think were the economic/administrative whizzes who helped bolster their county's prosperity/efficacy?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/10yjhm/who_were_the_great_administrators/
|
{
"a_id": [
"c6hw4r6"
],
"score": [
2
],
"text": [
"If you're looking into US history I strongly recommend you examine Andrew Jackson's contest with the [Second Bank of the United States](_URL_0_)."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Bank_War"
]
] |
|
6o86e9
|
Planets can have rings. Can stars have the same sort of rings?
|
I don't think Sol's asteroid belt would count as a ring because, I assume, it's not nearly as dense as the rings around Saturn. Can a star even have a ring so dense as to be very visible?
Thanks in advance!
|
askscience
|
https://www.reddit.com/r/askscience/comments/6o86e9/planets_can_have_rings_can_stars_have_the_same/
|
{
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"dkfl6hk",
"dkfvy12",
"dkfyc02",
"dkg19wq",
"dkg8e9d"
],
"score": [
65,
21,
9,
5,
7
],
"text": [
"It is definitely possible. \n\nFirst, a solid celestial body would have to enter the star's sphere of gravitational influence. Then, it would have to pass through the Roche limit. That's the distance where the tidal forces will rip the object apart. \n\nIf the object wasn't on a collision trajectory with the star before disentegration, then it will form a ring around the star.\n\n",
"If you don't think the asteroid belt counts as a ring (it *is* the actual solar equivalent of having a ring), then not really. The reason it can't have a dense ring of small particles in very close proximity like Saturn is because of how stars are born. Once the accretion disc has built a body large enough to begin fusion, the star \"lights up\" and blows away the rest of the disc, except for things that are a combination of too far and too massive. This would be the planets and the asteroid belt.",
"[Protoplanetary disks](_URL_0_) have similarities with rings. They don't live long, as the matter inside forms planets and asteroids and the star disperses whatever is left afterwards.",
"They would be much rarer and have shorter lifetimes, at least around actual stars (versus brown dwarfs). A ring forms inside the [roche limit](_URL_2_) of an object, which is where tidal forces from the more massive object are larger than the object's own self-gravitation. This doesn't mean that objects break apart there necessarily, but it does mean that objects that are mostly held together by gravity can be easily disrupted. It's somewhat more challenging to get objects into mostly circular orbits inside the roche limit of a star than to a planet, but it is possible.\n\nThe bigger issue is radiation pressure. Dust, pebbles, and rocks in close orbit around a star will experience strong orbital dynamics perturbations due to the [Poynting-Robertson](_URL_0_) and [Yarkovsky](_URL_1_) effects. These will tend to deorbit or blow away most of the stuff in the ring at a much faster pace than if it were around an outer planet like Saturn, because the solar radiation flux is so much higher.",
"Probably not. Here's why:\n\nThe principle people are referring to so far is the Roche limit, the closest a planet can venture towards the body it's orbiting before the force of gravity on the front-facing side differs from the force of gravity on the rear-facing side by *so much* that it exceeds the gravitational self-attraction of the planet. So now the net force of gravity is no longer attractive for that planet. As most of the rocky bodies in the solar systems are merely loosely-held balls of gravel rather than hard spheres - notable exceptions being the 4 inner planets - these balls of gravel will just pull apart as they orbit.\n\nIn fact, we can calculate the Roche limit for the sun when orbited, by, say one of those loosely-packed balls of gravel, more of less. Let's pick Ceres, the largest asteroid:\n\n > d = 1.26 R*_S_* * ( ρ*_S_* / ρ*_C_* )^1/3\n\n...where R*_S_* is the radius of the sun, and ρ*_S_* and ρ*_C_* are the densities of the sun & Ceres, respectively.\n\n > d = 1.26 * 6.96 * 10^8 m * ( 1.41 / 2.16 )^1/3 = 7.61 * 10^8 m\n\nYou see the problem? For a body that is denser than the object it's orbiting, the Roche limit ends up being dreadfully close to the surface of the larger body. In this case, the Roche limit's at 1.09 solar radii. By comparison Mercury's orbit is about 100 solar radii away from the sun.\n\nAt that distance I would imagine several things would happen: First the planet would likely melt. If it were torn apart by tidal forces then the little bits of rock and ice would likely melt, and/or vaporize. In fact, we can calculate the thermodynamic equilibrium temperature at that distance:\n\n > T*_eq_* = T*_sun_* * ( 1 - a )^0.25 * ( R*_sun_* / 2R*_orbit_* )^0.5\n\n > T*_eq_* = 5,770° K * ( 0.5 )^0.25 * ( 6.96 / 15.2 )^0.5 = 3,280° K\n\nThat's high enough that almost everything you're going to find in a rocky body is going to vaporize. It's higher than the boiling points of Gold, Nickle, Iron, Chromium, and Copper. So instead of forming a ring I would expect a body that close just to burn up and find it's bits & pieces scattered to the (solar) winds, so to speak."
]
}
|
[] |
[] |
[
[],
[],
[
"https://en.wikipedia.org/wiki/Protoplanetary_disk"
],
[
"https://en.wikipedia.org/wiki/Poynting%E2%80%93Robertson_effect",
"https://en.wikipedia.org/wiki/Yarkovsky_effect",
"https://en.wikipedia.org/wiki/Roche_limit"
],
[]
] |
|
4nv0it
|
why did linux get more popular then unix?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4nv0it/eli5_why_did_linux_get_more_popular_then_unix/
|
{
"a_id": [
"d4753z8",
"d4782p9",
"d47a1bi"
],
"score": [
17,
9,
4
],
"text": [
"It was free. It had no support guarantee, but the lack of cost made up for it. And because it was open source it could be ported to anything it could be compiled for, and there wasn't a big company making budgeting decisions based on volume sales potential keeping that from happening.",
"Unix was expensive (usually expensive as hell), and most variants required expensive (usually expensive as hell) hardware.\n\nThen, Linux cane along, and it was free or cheap (depending on which flavour you prefered). It gained a huge amount of traction, and soon become the leading Unix variant (yes, Linux is a full Unix).\n\nNow, there is no reason to go for some other Unix, as Linux has, by far, surpassed them.",
"Unix wasn't one thing, but a family of operating systems based on the original operating system developed by Bell Labs (Later AT & T). In the 80s/90s there was BSD, AIX, Solaris (SunOS), UnixWare, Xenix, HP-UX, IRIX, A/UX among others. There was the 'unix wars' where each vendor struggled to become the 'standard' unix. Compatibility between unixes was poor and each unix implementation was usually tied to a specific brand of hardware.\n\nNot only was Linux free, but it promised compatibility between hardware. Programs would need to be recompiled, but the tools etc would be the same, so it should just work.\n\nFreeBSD was also free, but it came too late. By the time all the legal issues were resolved, Linux had already 'won'\n\nHere is a good chart that shows the history of the unixes: _URL_0_"
]
}
|
[] |
[] |
[
[],
[],
[
"https://en.wikipedia.org/wiki/History_of_Unix#/media/File:Unix_history-simple.svg"
]
] |
||
36h00f
|
how come i can remember a certain moment from my childhood, yet i can't remember a maths equation i learned today?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/36h00f/eli5_how_come_i_can_remember_a_certain_moment/
|
{
"a_id": [
"crdw1y0"
],
"score": [
5
],
"text": [
"You have two forms of memory - short-term and long-term. The first is far from perfect but can get better with the proper training. So just after you learn it, your math equation is in short term memory.\n\nWhen you sleep, some of the long-term memories are created from the short-term memory experiences you had during that day, particularly when it really stood out. (For example, an afternoon playing will likely not be as long-term memorable as a trip to Disney). But if you got swamped with new information that day, not everything is permanently written down and so you forget some stuff like your equation.\n\nWhen you're younger and learning lots, you're pretty good at this conversion process, so many long-term memories exist and can be recalled well into adulthood. But the short-term ones that didn't get transcribed into long-term form are lost, just like that equation."
]
}
|
[] |
[] |
[
[]
] |
||
1acpia
|
Why are there 3 different names for meteoroids/meteorites/meteors?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1acpia/why_are_there_3_different_names_for/
|
{
"a_id": [
"c8w5gd9",
"c8w5ghn"
],
"score": [
8,
2
],
"text": [
"Because they are different by definition.\n\n**Meteoroid**: A small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.\n\n**Meteor**: A small body of matter from outer space that enters the earth's atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.\n\n**Meteorite**: A meteor that survives its passage through the earth's atmosphere such that part of it strikes the ground.\n\n\n\n",
"I should think this is something you can simply look up in a dictionary.\n\nA meteoroid is a particle from a comet or asteroid. A meteor is the glowing wake made in the atmosphere by particles being shed.. A meteorite is a chunk that makes landfall."
]
}
|
[] |
[] |
[
[],
[]
] |
||
2vp22s
|
why do mobile video games have so many commercials on tv all of a sudden?
|
Also, getting a sponsor like Kate Upton, that seems so out of place
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2vp22s/eli5_why_do_mobile_video_games_have_so_many/
|
{
"a_id": [
"cojn4gx",
"cojna4h",
"cojnnbk"
],
"score": [
3,
5,
3
],
"text": [
"Mobile phones, and thus mobile games are so popular now that it makes financial sense for big-name games to spend the big TV money in order to sell more games.",
"Mobile games have the best potential to be profitable because they cost far less to develop than traditional PC or console games and everyone has a phone. A few companies have figured it out (including those people at Candy Crush who sue anyone that uses the word \"saga.\" They're the new monster cable of frivolous lawsuits)",
"\"Free to play\" is a very effective advertising tool and the \"cinematic\" aspect of these commercials are much better lures than screenshots. Of course once you are in the game, you quickly realize it's not so free. But I am sure they have a target retention rate, so even with the loss of players, they are making more than enough money to offset the cost of Kate Upton."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
476t1w
|
how can a person have 8 pack abs when theres only 6 rectus abdominis?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/476t1w/eli5_how_can_a_person_have_8_pack_abs_when_theres/
|
{
"a_id": [
"d0anp5b",
"d0ar1ga"
],
"score": [
6,
19
],
"text": [
"It's partly genetics and partly an illusion. Without the right genetics the illusion is much harder to give off and thus would need intense exercise on your lower stomach & having an incredibly low body fat %, but it's not something that can be real without having the genetics for it.",
"Actually you just have 1 rectus abdominus muscle, which is split in the middle longitudinally by linea alba (white line). And there are tendinous insertions horizontally that gives the impression that you have 6 different muscles. There are normally 3 of these insertions, hence 6 bulges, but some have 4 of them making a 8-pack."
]
}
|
[] |
[] |
[
[],
[]
] |
||
bk9mrg
|
what are stocks and what is insider trading? how are they related to each other?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bk9mrg/eli5_what_are_stocks_and_what_is_insider_trading/
|
{
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"emezl05",
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"emezqse",
"emf01yr",
"emfdi5i"
],
"score": [
5,
2,
2,
3,
2
],
"text": [
"This is VERY ELI5\n\n & #x200B;\n\nStocks are a share of ownership in a company. Insider trading is when someone close to or with connections inside a company know of a large move (either positive or negative) the company is about to do that is going to effect the stock price. They then act on this information to either buy a bunch or sell a bunch of the company's stock before the information becomes public.",
"A stock is a part of a company simply speaking. There is a limited amount of shares, if you have more than 50% you basically have the say in that company.\n\nInsider trading is if someone with inside knowledge uses that knowledge in order to gain an advantage for making money.\n\nAs an example you have a lot of stocks/shares in a company but you also know internal stuff, e.g. a lawsuit or another problem that will kill the price of the share. They then sell before it's known to the public so they don't lose money. It also works the other way around, buying a lot of shares because you have inside knowledge that the price will skyrocket (new invention hitting the market for example)",
"Stocks are fractions of ownership in a company. If you own a stock in the company you can vote on certain decisions of the company. If you own 50.1% of all the stock issued you can make controlling decisions of the company.\n\nInsider trading is making stock trades based on information that is not yet known to the public. For example if the CFO knows company A is about to buy company B that will likely impact the stock price of both companies once the info is released. So if he were to make a trade beforehand he could make money based on this “inside information” - thus it is not allowed.",
"Stocks are shares in a company. \n\nIf there are 100 shares of a company, and you own 10 of them, you own 10% of that company.\n\n\nInsider trading is the use of information not available to the public to make stock trading decisions.\n\nFor example: Say a CEO knows that his company didn't get approval for the drug it produces and the stock price is going to fall. He calls up Martha Stewart and tells her to sell her shares *before* the news of the denied approval hits the media and causes the price to fall.\n \nThey have made an illegal insider trade because her sale was based on inside information.",
"They definitely can and this is the most typical case. Senior execs have windows that they are and are not allowed to trade. It is all public information and must be filed with the sec. big swings outside of their normal trading is investigated."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
|
8a43ua
|
why does skipping five seconds of a video often take longer due to buffering than just sitting through the five seconds?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8a43ua/eli5_why_does_skipping_five_seconds_of_a_video/
|
{
"a_id": [
"dwvtmtz"
],
"score": [
20
],
"text": [
"The way online video is compressed, you're receiving data that represents incremental updates from the last frame. If you start playing the video at the beginning, it all works as intended.\n\nHowever, if you start playing in the middle, you need to process incremental updates for some time period prior to the frame you want to see before you can display it. It takes time to download both the incremental data and process it."
]
}
|
[] |
[] |
[
[]
] |
||
ajezn3
|
Does a radar gun in a moving vehicle function the same as one in a stationary vehicle?
|
Car A has the radar gun and is moving at a constant 75 miles per hour.
Car B is next to Car A moving at 75 mph, does the radar gun clock Car B at 0 mph or 75 mph?
Car B is moving past Car A at 80 mph, does the radar gun clock Car B at 5 mph or 80 mph?
Car B is moving at 70 mph and being passed by Car A. Does the radar gun clock Car B at -5 mph or 70 mph?
Car B is stationary and being passed by Car A. Does the radar gun clock Car B at 0 mph or 75 mph?
|
askscience
|
https://www.reddit.com/r/askscience/comments/ajezn3/does_a_radar_gun_in_a_moving_vehicle_function_the/
|
{
"a_id": [
"eev5p2y",
"eev6css"
],
"score": [
16,
3
],
"text": [
"All detectors can only tell you relative speed. So that means that a stationary radar would detect 0 in the first case, 5 in the second and 5 (speed is absolute value of velocity) in the third, 75 in the last. You have the right idea. It's not a mistake. The nature of physics is that the relative value is the absolutely real answer - assuming you've chosen yourself as the frame of reference.\n\nWhich doesn't matter if your radar unit includes a detector for your own speed, which can then be added or subtracted from the target. That's what police use. In many well funded places cars have internal systems that have antennas mounted on the rear and front, which can detect accurate speeds of cars moving the same or opposite direction and ballpark speeds of things moving off axis. \n\nIn some cases you can also detect multiple objects, including stationary ones that are known, and get an even more certain result. Either way the result is that you can return to a universally agreed frame of reference (the Earth's ground) by a simple transformation.\n\nSo they do work differently, but only in the data processing. The radar itself is the same. Your ticket will be the rounded down end of the margin of error, but if you're speeding enough that's still not great.\n\nSimilar computerized systems are used on ships, aircraft and anything else that might be moving when you need a reading. Sometimes RADAR units are used to determine your own speed and position as well. They're pretty versatile for being very simple in concept.\n\n_URL_0_\n\nThere's an example. Note that it plugs into the car's data port to pull vehicle speed info (VSS).",
"It will report a relative speed. In your first question, if both cars are traveling at 75 mph then it should read zero.\n\nThe light leaving the radar gun and bouncing off the speeding car is totally unaware of the ground. That should be easy to accept with just [Galilean relativity.](_URL_0_) You can throw a ball upwards in a moving car and catch it just like you were stationary. If there were not much air resistance you could play catch between two parallel moving vehicles.\n\nBouncing light off an object does not work quite like bouncing a rubber ball. Fiddling with moving light sources, moving mirrors, and photon detectors would eventually lead you to some very odd conclusions about the nature of light, time, and space and also lead you to the rules needed to build a radar gun. Take things one relativity at a time though."
]
}
|
[] |
[] |
[
[
"https://www.stalkerradar.com/law_dsr.php"
],
[
"http://physicscentral.com/explore/plus/galilean-relativity.cfm"
]
] |
|
9jbopb
|
how does a gym's business model hold up? the equipment is insanely costly and the memberships cost next to nothing in most cases. how does it pay off the investment and become a stable income source?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9jbopb/eli5_how_does_a_gyms_business_model_hold_up_the/
|
{
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"e6r074n"
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"score": [
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2,
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2,
2
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"text": [
"I think a lot of it relies on people paying for gym memberships that they never or rarely use. ",
"It's like planet fitness cheap membership so everyone and their mom signs up, but then they literally never go. So tons of $20. A month payments and if you forget a yearly fee but noone uses it. ",
"Although the equipment is costly, some gyms (like mine) keep the same equipment for a very long time. Once it is paid for, maintenance costs are small compared to membership income. \n\nEdit: missing word added.",
"Relevant to add that in many cases, the business model just doesn't hold up. Especially in smaller towns with few potential members they can barely be breaking even, if they are even doing that, and just keep going in a hope that enough people will sign up. \n",
"A lot of budget gyms don't actually pay their staff.\n\nYou get a job as a Personal Trainer and work as a receptionist and a cleaner and you take fitness classes that are generally free for the gym users.\n\nYou then use this to recruit people as clients for your personal training business and charge them $40 an hour and the gym lets you use their facilities for your classes.\n\nThe trainers don't need a studio and the gyms don't need to pay their staff.",
"The only example I can speak of from experience is a local council-operated gym system that last year effectively made a small loss. By far the biggest expense is employee salaries, which account for most of the operating costs. These salaries include maintenance, but the annual expenditure on new equipment is comparatively small. Income comes from three main sources: memberships, fees and hiring out their facilities.\n\nIn simple terms, the business model is \"charge people enough for memberships and one-off visits to pay for most of the running costs of the gym, then hire out gym facilities on slow days to make up the rest\". This year, they will increase all the fees a bit to make up for last year, when the fees were slightly too low to make a profit in pure economic terms. Overall, the system makes the local area money by improving general health, providing employment and taking virtually no tax subsidy. ",
"TLDR: The gym only has 10 machines in it, but that can actually support 200 memberships easily.\n\n\\-----\n\nThe model depends upon people paying for a membership and only occasionally showing up to the gym, plus the low depreciation/maintenance of the machines.\n\nThis is why gyms emphasize \"don't bang the weights.\" There isn't much risk of you hurting yourself, but there is a risk of you breaking equipment.\n\nThat's also why gyms emphasize year-long contracts and auto-pay systems when you join. If you use the gym often you will be willing to remain a member. If you don't use the gym often, you will likely forget about the membership. Some gyms also have a termination fee, or require you to quit in-person so that a sales rep can talk you out of it.\n\nAlso, lots of people join around New Year's with the idea of getting in shape. Next year rolls around and the gym membership expires, but hey, I should start going to the gym again as my resolution so I won't cancel.\n\nSo there is a really high members-per-machine ratio, with most members not using the machines often (or at all).",
"Already some great answers here. I would also like to add that it's likely that national chains especially and probably some other gyms arrange bulk discounts. Let's say a treadmill costs 2000 dollars if you go to the store and buy one, when the manufacturer sells them for 1200. But the store is getting a cut and you're only buying one.\n\nBut a national chain might go straight to the manufacturer and buy them for 1200 rather than 2000, and if they're buying hundreds at a time and warehousing them for building new locations or expanding or having reserves, they might strike a deal at 1000 per treadmill. This is very common in industry where a discount can be struck for making a large order, because it is still a huge amount of money and it guarantees the manufacturer some work for a time.\n\nNow a small-time gym might instead go to the store selling for 2000, and make a deal where they will buy say 10 treadmills at 1800 each. The store is still making money by selling 10 treadmills at once just less profit *per*, and the gym saves a bit of money on equipment.\n\nIn both cases it is hoped that the purchaser will come back to them for replacement parts, which is also a handy source of revenue.",
"Also it might have something to do with some gyms making it very difficult to cancel a membership with an automatic payment "
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
3h227v
|
What happened to the territory gained by Justinian I?
|
I was watching the awesome Extra Credits season about Justinian and Theodora, how he recaptured North Africa, Sicily, Italy and even a bit of Spain. Unfortunately, the series ended after the defeat of the Ostrogothic army after it wanted to recapture Rome.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3h227v/what_happened_to_the_territory_gained_by/
|
{
"a_id": [
"cu40fj4"
],
"score": [
3
],
"text": [
"It was lost again.\n\nIn Italy the war with the Ostrogoths lasted for decades and devastated the country. Some historians hold this war to be the true end of antiquity. As Goldsworthy puts it, it \"probably destroyed many aspects of Roman culture and society that had survived the collapse of the Western Empire.\"\n\nAlthough the Byzantines eventually defeated the Ostrogoths and took control of the whole of Italy, the Lombards (Or Longobards, i.e. Longbeards. Another German tribe) invaded Italy very soon after Justinian's death, and took over most of the interior. The Byzantines held on to coastal cities and Sicily, and over the centuries afterwards would sometimes regain parts of Italy, but they never got anywhere close to achieving Justinian's territorial ambitions. They fought over it as late as the reign of Manuel Komnenos, who tried to regain control over the southern ports there in the 12th century.\n\nThe Spanish possessions were contested by the Visigoths, and though the Byzantines held on for some decades, and even made some temporary gains by exploiting Visigothic dynastic conflict, they lost all their mainland possessions in the 7th century even before the Muslims invaded. (They held on to the Balearic islands for a bit longer.)\n\nAfrica remained a Roman possession for several generations, until it fell to the Arab invasion along with Egypt and Syria later in the 7th century.\n\nThe bubonic plague that devastated the empire shortly after the start of the Ostrogothic wars likely had something to do with the empire's inability to hold on to its conquests, but Justinian's projects had also been opportunistic and ended up opening up several new fronts in an empire already struggling to defend its existing possessions from attack. Hardly anybody considers the loss of the new conquests surprising. "
]
}
|
[] |
[] |
[
[]
] |
|
163ucx
|
How do we know the orbit of the sun?
|
We've only had the math and technology to accurately take measurements for a hundred years out of a 30 million year cycle. Are our instrements really that good or are we making pretty big assumptions?
|
askscience
|
http://www.reddit.com/r/askscience/comments/163ucx/how_do_we_know_the_orbit_of_the_sun/
|
{
"a_id": [
"c7shlbv",
"c7shze4"
],
"score": [
2,
3
],
"text": [
"Are you thinking about how the sun travels around the Milky Way?",
"Yes, our instruments are actually are that good, but the reason you're looking for is our toolbox has grown significantly since the days of Galileo. We can collect data much more accurately and at a much greater distance than ever before. \n\nTo the best of our knowledge, the Milky Way is a [barred-spiral galaxy](_URL_0_) , and most barred-spiral galaxies we observe spin like a giant record on a player. By looking at the distant stars in our local galaxy and observing the [doppler shift in the starlight](_URL_1_) we can get an idea of what direction the galaxy is spinning. Stars moving away from us look more reddish than stars moving toward us. This is due to a change in the light-particle frequency because of the relative motion between us (Earth) and the star we're looking at. \n\nSince our star is part of the galaxy, it's snared in the same rotational movement the rest of the galaxy is locked at, which gives us an idea of which direction the sun will move as the galaxy spins, giving us its orbit and velocity. We can even tell the vector the sun uses to travel through the galaxy. I've read the planets of our solar system orbit the Sun on its Y-axis, not horizontally like charts always show. Supposedly, the solar system stands on its side as it burns around the Milky Way, but I can't find any supporting information about this."
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Milky_Way",
"http://imagine.gsfc.nasa.gov/YBA/M31-velocity/Doppler-shift-2.html"
]
] |
|
48zmpw
|
how do the inner leaves of cabbage perform photosynthesis?
|
From what I know, it grows from the inside out, the inner leaves never actually being exposed to sunlight.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/48zmpw/eli5_how_do_the_inner_leaves_of_cabbage_perform/
|
{
"a_id": [
"d0nvzgy",
"d0ny3ws"
],
"score": [
5,
2
],
"text": [
"The inner leaves may not see the sunshine but the entire plant acts as a \"unit\". Much like kindergarten, sharing is important for the success of everything involved ",
"You need to remember that cabbage, as we know it, is the result of centuries of selective breeding. The plant you see isn't something that evolved naturally. [There's many different food crops in the same family](_URL_0_) - cabbage, broccoli & mustard are among them.\n\n[Quite a few of the varieties](_URL_1_) have the inner leaves exposed and [the wild form](_URL_1_#/media/File:Brassica_oleracea0.jpg) doesn't even bunch up into a ball."
]
}
|
[] |
[] |
[
[],
[
"https://en.wikipedia.org/wiki/Cruciferous_vegetables",
"https://en.wikipedia.org/wiki/Brassica_oleracea",
"https://en.wikipedia.org/wiki/Brassica_oleracea#/media/File:Brassica_oleracea0.jpg"
]
] |
|
3j5wwy
|
how does applying toothpaste to a cd to help fix scratches work?
|
Is it just a hoax? I've tried before and never could get it to work, but my fallout 3 disc is scratched all to hell and I want to play it before 4 comes out. (I know 4 comes with a copy of 3 but I don't want 4 sitting on the shelf for a month before I can play it)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3j5wwy/eli5_how_does_applying_toothpaste_to_a_cd_to_help/
|
{
"a_id": [
"cumkaud",
"cuml5ix",
"cumob58",
"cumqbiy",
"cun3tj4"
],
"score": [
4,
8,
22,
13,
2
],
"text": [
"Toothpaste is a very fine polish, so it helps to polish out the scratches. There are a number of potentially abrasive ingredients potentially even silica (sand).",
"The lasers in a CD/DVD drive can read through scuffs & dirt. What they can't read through is a big scratch because that'll cause the laser beam to reflect off in wild directions & not back to the sensor.\n\nOne of the key ingredients in toothpaste is a fine abrasive - sort of a polishing compound. You can use that to lightly grind down the edges of the scratch, leaving just a scuff that the drive can read through.\n\nMetal polish, like Brasso, is also good. I think it's slightly more effective but *everyone* has toothpaste in their house already.",
"The data on a CD, DVD, etc is stored on the label side, on the surface of a thin sheet of metal that can be seen through the plastic. The top of a CD is usually pretty well protected by being a nice hard surface, but the bottom is just a plastic that is prone to being scratched.\n\nIf you have scratches on this side of the CD then it can deflect the laser that's trying to read the information. Polish the scratch off of the surface and the data can be read.\n\nToothpaste just happens to be a pretty good mild abrasive. Off the shelf CD repair kits work similarly and may have a clear compound to fill the scratches. ",
"You make a scratch that's bigger than visible lights wavelength into little scratches smaller than the wavelength of visible light.",
"It's basically polishing the scratches out of the protective plastic shield. The data is on the metal part in the middle and/or what forms the top/label of the disc.\n\nAnd if you are serious, some car polish or cutting compound will work as well. (heck even fine sandpaper if the scratch it deep enough). Start with cutting compound, then polish. Should get it going well enough to at least rip the disc."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
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