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48pt5d | why is it that when flies land on our lcd/led screens, they don't get affected when we move windows or make some rapid movement which results in some colour change in the screen? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/48pt5d/eli5why_is_it_that_when_flies_land_on_our_lcdled/ | {
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"As in, the fly doesn't get scared and fly away?\n\nI dont have an answer, but just trying to understand the question better.",
"Fly fear responses are based mostly on air currents and visual stimuli from above the fly, because that's where predatory threats come from. They don't have much in the way of general intelligence, and escape responses are hardwired so they can be faster, so random visual stimuli from unexpected directions don't really register.\n\nIf you want to see something funny, though, put a little jumping spider on a computer screen. It _will_ follow the cursor around like a cat after a laser pointer, because jumping spiders are incredibly visual and keyed to look for prey running around on surfaces. ",
"I once seemingly gave a fly a seizure by running a program to flash colors as rapidly as possible. It fell off the screen and started twitching. I've tried to do it again, though, and it hasn't worked. I think maybe that particular fly had genetic issues."
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817itq | how are molds for shaping molten metal made? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/817itq/eli5_how_are_molds_for_shaping_molten_metal_made/ | {
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"Generally the cycle stops when you make the original mold out of ceramic (which generally has a very high heat resistance) one time."
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e2eeip | why are the doors bigger on 2 door cars? | I mean obviously, I get that there’s more space to make them larger; but from a manufacturing point of view, surely it’s easier to only make smaller doors made for the 4 door models, and just use them on the 2 models as well?
On top of that, two door’s struggle to fit into tighter parking spaces because the larger doors require more space to open, which is counter intuitive when you consider two door cars are thought of as smaller.
I’d have thought smaller doors would be stronger too, since shorter cuts of metal will flex less easily, and it would give more space to better reinforce the rear, door-less part of the car.
Am I overlooking something obvious here? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/e2eeip/eli5_why_are_the_doors_bigger_on_2_door_cars/ | {
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"If the car is 2 door but still have 2 rows of seats you need larger door else it would be almost impossible to get into the back seats.\n\nI have not idea if there is a car with a 2 and 4 door variant where the 2 door variant only has front seats and the 4 door variant has a front and back seat where you using the same doors could mase sense."
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4rrh18 | how do credit cards and scanners work? | From the time I swipe my card for X amount of money to when I look at my bank account to see that the money is X amount lower, what's going on in between? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4rrh18/eli5_how_do_credit_cards_and_scanners_work/ | {
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"Swiping your card is just having your magnetic strip read by a head in the device (think about cassette tapes or VHS tapes). It pulls your number from your card, and then over the internet, contacts the bank to authorize the transaction.\n\nThe bank will then authorize the transaction back to the merchant, and then put that as a pending action in your account, which will resolve itself after a certain amount of time."
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2flceq | as i understand it, our bodies react to illnesses with symptoms (e.g. we are sick to expel harmful bacteria in the stomach). however it is the symptoms of illnesses that often kill us (e.g. dehydration from diarrhea). so what would happen to someone whose body did not react to an illness? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2flceq/eli5_as_i_understand_it_our_bodies_react_to/ | {
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"We can see what happens to people who's bodies don't react to sicknesses by examining severely immune-compromised patents such as those with Acquired Immunodeficiency Syndrome (AIDS). They die, horribly and in short order.",
"They would say you have AIDS.\n\nMany common diseases that you wouldn't think twice about would easily be able to kill you.\n\neg, the common seasonal flu is a respiratory disease that, if left alone long enough, will leave your lungs damaged to the point that you suffocate."
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18olax | why does r/atheism have a hate crime petition being circulated against it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/18olax/eli5_why_does_ratheism_have_a_hate_crime_petition/ | {
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"R/Atheism is now large enough to be a default sub-reddit for new members. Christians can't stand that.",
"/r/atheism spends a lot of time making fun of religions, religious people, holy books and that kind of thing. For a lot of people, their religion forms a big part of who they are and when you criticise or insult their religion, they take that as criticism or insult to themselves. \nSo, where the best submissions to /r/atheism are careful to criticise, say, a particular belief, the people who hold that belief tend to take personal offense rather than intellectual umbrage and react viscerally rather than with counter-arguments. Of course, plenty of submissions aren't careful about the distinction at all and will outright mock various religious people. The (ex?) Pope is a notable recent example. \nSo, on one side you have people who post things ranging from \"ridicule is an apt response to ridiculousness\" to pictures like [this](_URL_0_) (NSFW) and on the other side you have people who not only think that that attitude is needlessly rude but who hold that personal beliefs should be beyond reproach and who revere holy laws forbidding blasphemy on pain of death. Consider the stage set for conflict. \nWhile both sides would be happier if the other simply stopped talking, I think it's important to note that the religious side is the only one taking steps to shut the other up. ",
"Most of /r/atheism consists of screengrabs from Facebook, reposted quotes from famous atheists and derivative 'advice animal' type stuff that isn't good enough for any other subreddit. Fortunately, there's the occasional gem as well.\n\nIt seems that some Christians have come to the conclusion that a community who's posts consist mostly of negative, derisive, rude, unkind, critical, sarcastic comments about their religion and its followers doesn't like them very much. \n\nI can't say I blame them really. I think it's fair to say there are quite a few people who post in /r/atheism that really don't like Christianity very much at all. In fact, there's probably a fair amount of 'hate-ful' speech on /r/atheism. This is protected free speech.\n\nUnfortunately, some Christians have mistaken this for 'hate speech', which is speech that incites violence or prejudicial action against a group because of some protected characteristic (i.e. religion). I have not seen a single example of this.\n\nFree speech - 'I think Christians are stupid'\n\nHate speech - 'Kill all the Christians'",
"Many Christians think that it's okay to ridicule other people's beliefs if they are genuinely silly, but also think that it's blasphemy for their own to be ridiculed. Welcome to the world of double standards.",
"That subreddit is a joke. I'm an atheist, even I can't stand it."
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37wjb3 | why are foxes not a popular pet to have, they're like a mix between a cat and a dog | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/37wjb3/eli5why_are_foxes_not_a_popular_pet_to_have/ | {
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"They're not legal to have. Animal rights laws prohibit the domestication of new animal species as it requires cruel practices to achieve.\n\nRussia has soldiered on, and while they have managed to breed friendly foxes, there is still quite a bit of animal cruelty left before they've bred foxes that are house trainable.",
"Cats and dogs have *thousands* of years of domestication behind them to make them more suitable as pets. \n\nFoxes are stinky, wild, difficult to train, may violate local laws, will not have commercial food designed to give them a healthy diet, and so on. You can tame one but it won't be domesticated.\n\nSome work is being put into making truly domesticated foxes, initially begun as a way to try to make more docile animals for the fur industry, but they're still a long way from being as easy to care for as a puppy.",
"They are cute, but they are not domesticated. There's a significant chance that, if you choose to live with a fox, it will mess you up. ",
"They're not domesticated. [In Russia](_URL_0_) a scientist domesticated foxes through selective breeding, however it took several generations."
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2kbw0j | why some heritage sites are not fully restored, i.e parthenon? | I know work is done to preserve it but why not stuff like that to return it to its former glory. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2kbw0j/eli5why_some_heritage_sites_are_not_fully/ | {
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"Because 1) when we say restore what we really mean is rebuild over the top of what is actually there and 2) that costs a lot of money, these things weren't cheap to build then and they are still expensive now. \n\nAlso I don't want to go and see a fabricated modern thing and neither do most people, there's something about seeing an ancient monument as is, knowing those stones were laid hundreds/thousands of years ago by people we will never know. A recreation/restoration is meh.",
"Why would you want to see it that way?\n\nEdit: they actually do a lot of these types of restorations in China and it sucks. Whenever I go and look at ancient buildings, monuments, etc. they're all touched up and perfectly restored. I guess it works for them but I'd rather be more in wonder at the antiquity of it."
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1q1dsr | stock market indexes | You hear on the news all the time that "The Dow was up X points today" . What exactly is a point? Can I invest in the Dow and when i hear this know my investment went up x amounts of dollars that day? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1q1dsr/eli5_stock_market_indexes/ | {
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"It's more of an indicator of overall economic strength. Seeing the Dow go up X points leads people to say \"Hey I'm a stockholder in 3 companies on the dow, i might have made some money\"",
"The Dow is a collection of many companies - as an 'Index', it is designed to be an overall indicator of a particular industry or market.\n\nFor instance, take a look at the [MAC Solar Energy Index](_URL_0_)\n\nYou can see the companies that the Index holds - the index then, depending on how well it is managed and what stocks it uses, can be seen as a sort of 'meter' for how a particular market is performing.\n\nTypically you would not invest directly in the Index - in the case of MAC, there is an ETF called Guggenheim Solar ETF (TAN) that you would invest in.\n\nSo with the Dow, the index is [DJI](_URL_1_), and the ETF you would invest in (or an ETF you would invest in) [DIA](_URL_2_), I believe. You could also invest directly in one of the companies that the Dow index tracks - which one you chose depends somewhat on the kind of investor that you are. /r/investing has more discussion on these kinds of things in general",
"Indexes are a group of company stock, the sum of which is often called points. So saying the Dow was up X points today means that if you owned all stocks in that make up the Dow, you would be up X dollars that day.\n\nIf you want to invest in an index, it's usually easier to simply invest in an indexed mutual fund tied to the desired index.",
"Stock market indices are measurements of the relative health of the securities on a particular exchange. The actual number you see is derived from applying some kind of formula to the value of a specific set of stocks.\n\nFor example, the Dow Jones Industrial Average (the DJIA or Dow) is the go-to index for the New York Stock Exchange (NYSE). There are 30 specific companies in the dow. (There are always 30, though some are swapped in and out every few years. Indeed, three were changed out recently.) These 30 \"component\" companies are chosen because they're large, proven companies that are representative of the health of their respective industry sectors. The Dow used to be a simple weighted average of those stock values, but it's since grown to be a little more complicated than that. You can read more about it [here.](_URL_0_)\n\n > What exactly is a point?\n\nI think I addressed that above. It's an indicator of how the particular market did that day. It helps make spot check references to the market and explain/predict broad trends.\n\n > Can I invest in the Dow\n\nKind of. You can always buy into \"index funds,\" which are sort of pools of stocks tied directly and indirectly to the index's components. Your investment will closely track the fluctuations in the index.\n\n > and when i hear this know my investment went up x amounts of dollars that day? \n\nNot really. The value of stock indexes - particularly the Dow - aren't expressed in dollar terms. So when you see the Dow is at 15,000, there's no dollar sign in there. It's just a number. How well/poorly your investment does, in dollar terms, is a direct result of the value of the stocks you've invested in.",
"Indexes are simple ways of tracking what several comanies are doing. The Dow (technically the famous index is just the industrial portion of a broader Dow index) is a very old index (created when calculations would all need to be done by hand). So it's calcuation method is designed to be very simple (it's weighted by price). As such it's not a very good index--prices are arbitrary based on how frequently a firm splits it's stock, Google would have a very high weight were it included in the DOW. \n\nA point is currently a roughly $0.15 move in the price of any of the 30 component stocks (the divisor changes with the firms in the index and any splits or possibly dividends that occur during their time in the index--but it's published in the WSJ). \n\nYou can buy mutual funds based on the DOW (which means an investment advisor does their best to replicate the DOW's performance). They're usually close, but indexes don't need to buy and sell stocks or hold money for redemptions so there's usually some slight differences. Holding one would allow you to get quite close to a relationship between the dow's point movements and your investment's value. "
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dcuyre | if it’s racist for a white person to do “blackface”, is it also considered racist for a black person to do “whiteface”? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dcuyre/eli5_if_its_racist_for_a_white_person_to_do/ | {
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"I would hope so...kind of missing the concept if it wasn't right?",
"It's equally racist for anyone to dress or apply makeup in order to appear as another race.\n\nWhether or not it causes outrage and lashback is a matter of public opinion. Chances are White people aren't going to complain about the movie \"White Chicks\" with the Wayans brother nearly as strongly or with as much public support as Black people would compalin if there was a movie called \"Black Chicks\" starring Luke and Owen Wilson.",
"Impersonating any ethnicity including your own by adopting physical or behavioral distinctions for the purpose of entertainment / mockery or anything of provocation is considered racist in most of civilised society\n\nStill funny tho",
"Not really. White people have oppressed dark skinned people for the past thousand years or so and continue to do so. They haven't even begun making amends for that nonsense. Also, white people own pretty much everything. They haven't had to struggle because of their skin color for even a moment. They don't get to be sensitive about their race. If they can't take a joke fuck em. They have it coming."
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2fl0ht | lip-syncing/miming as a practice widely-accepted both by fans and the music industry? | As a live music nut, I prefer my music actually sung by the musicians as intended, rather than hearing a track that is being mimed by a "singer." So why does fans of musicians, mostly of pop artists, accept this as part of the live music experience, and not expect more out of their dollar? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2fl0ht/eli5_lipsyncingmiming_as_a_practice/ | {
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"Because you are thinking about pop concerts the wrong way. Think of live pop artists as performers for the night instead of musicians. The concert is just an elaborate stage show. There is still singing, by the way.",
"Depends on the performer, some \"singers\" cannot actually sing very well and rely on post processing and are usually successful because they are a performer. There are a lot of singers who do sing live. The reason its especially common in pop is that it is a genre of music that often has a lot of processing and effects added that can only be reproduced in a studio and editing suite, even if the performer can sing it can be troublesome adding and layering multiple vocal effects live."
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1jkdvs | r/braveryjerk | Is this essentially a circle jerk for Snoop Dogg fans?
Why bravery?
What's all the Ron Paul stuff?
Thanks,
Narwhal212 | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jkdvs/eli5rbraveryjerk/ | {
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"It's a fifth level circlejerk. They're mocking the mockery that is mocking Reddit using lowest common denominator mockery tactics. Snoop just does what Snoop does. Don't try to make sense of any of his actions.",
"As /u/t33po said, it's basically the meta meta meta of meta reddit commentary.\n\nSo they are making fun of you making fun of the red headed kid who made fun of the fat girl because she made fun of the other kid who didn't understand math.\n\nnot only that, but they are also making fun of WHY each level chose to make fun of the other.\n\nWhich gives them a range of topics from you, to your life, to your decisions, motivations and it repeats every level. \n\nPart of the reason that subreddit is so popular is that its somewhat like a game of where's waldo, only instead of waldo, you're looking for a reference to something on reddit. (or a reference to a reference, etc etc etc) You wander along and you see something! you understand it! It makes you laugh, you click the comments, you sort've get the next thing, over and over.\n\nSnoop is a frequenter of /r/trees. The users of which tend to get into zany situations or make odd comments (10guy) moreso than the rest of reddit. \n\nBravery, in my opinion, is used sarcastically. It's a form of meta judgement. Shouting RONPAUL2012 in the middle of any politics thread was bound to elicit support and upvotes. So people would mock those that did it, you're so brave, jumping on the band wagon.\n\nA lot of the stuff you read may seem like nonsense, but if you dig deep enough, it has roots in something, which sometimes, users recognize, and it's why they keep coming back looking for more gold.\n\nor at least thats what i think.\n\n"
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4vqpna | when they say that bees "dance" to describe the location of flowers to other bees, what exactly are they doing and how are other bees able to interpret this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4vqpna/eli5_when_they_say_that_bees_dance_to_describe/ | {
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"It's called the waggle dance, and will blow your mind. Basically, the bees do their dance at an angle from a vertical line, and the angle from the vertical is the angle from the sun.\nThis video does a great job explaining:\n_URL_0_\n\nSource: I work for a bee company. The crazy things these little gals know how to do are mind boggling, and essential to keeping humans alive",
"Bees that have found a good source of food is often observed wiggling amongst their fellow bees when they get back to the hive. Other bees would be flocking around and then go out to the same spot that the first bee found. For a time it was thought that the movement of the bee were telling the other bees where to look. There were attempts at interpreting the dance. However more serious studies have not found any correlations between the movements of the bee and the location of the food. It is more likely that the wiggling is designed to spread the scent to the rest of the colony."
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5tjkg1 | why do the pictures nasa releases to the public look like cgi? | I always notice that NASA releases photos and they almost always looks like CGI planets rather than real ones. Why is this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5tjkg1/eli5why_do_the_pictures_nasa_releases_to_the/ | {
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"A lot of NASA images are color enhanced because most of the light is outside our visual spectrum. There's also that if the images are from planets outside of the solar system then they are CGI artist impressions/speculations about what the planet might look like.",
"Part of it is because space lacks reflections. \n\nReally good CGI makes great effort to map all of the light sources and reflections in a scene. And I don't mean just mirrored reflections, but also the way light bounces off a wall and interacts with something like a couch. And there is also light from the adjacent room hitting that couch. So to make a realistic CGI couch, you have to model how different types of light hit the couch from dozens of angles. \n\nBut in pictures of planets, there is usually only one light source: the Sun. So just like CGI modeling a couch with only one light source will look \"fake\", a real rock in space tends to look fake with only one light source. \n\nIt is actually pretty easy to create a convincing asteroid in a 3d modeling program like Blender. But a realistic couch? That's hard.",
"It's also worth noting that many space probes don't carry the cameras we use day to day. \n\nThe cameras they carry are tuned for capturing particular types of light, which provides an image more useful to scientists studying the planet (just like how document copiers make really high contrast copies - useless for regular photos but makes text more readable). \n\nAs a result the images we see are either the wrong colour (colour shifted or showing colours we can't normally see) or artificially enhanced to try and make them the colours we would see (which is a difficult process). ",
"The \"cameras\" NASA has often do not work like normal cameras, i.e. they might record infrared, UV, even x-ray or radio spectrum. This depends on what they want to measure. There are also cameras for the visible spectrum, but those are not that interesting from the physics point of view, so NASA usually puts in other measurements technologies into their probes.\n\nThe raw data then is sent back home and scientifically analysed. In that process, the raw data is worked on, and people basically decide what is a) most useful for science or b) what looks the \"most\" close to what it would look in RL. And you also have c) how do you represent a infrared image in visible colours for displaying? If you have an gamma ray spectrum of a sun, how do you represent that as \"visible image\"? If you have a massive nebula that you only \"see\" because of absorbed infrared from a planet behind it, how do you visually represent that data? If we went there, we'd - with our eyes - see nothign at all. Those cases come with a lot of artistic freedom.\n\nSo, in short, NASA imagines often look \"photoshopped\" because... they are. This does not take away their scientific accuracy.",
"[Example](_URL_0_)\n\n[Images](_URL_1_) of what OP is likely refering to.",
"Film production designer here. Everyone else has already answered your question, but I thought I'd add one small bit of trivia, that is somewhat obvious but still manages to trick even me.\n\nAs NASA photos are the primary and key detail reference source for all sci-fi films and animation, they end up being composites and merged with concept materials for every part sci-fi and fantasy technology.\n\nAnything from a Megatron's elbow joint to a space-age toaster may have been in some way shaped or modeled in part to resemble a physical piece of actual space tech.\n\nAs we are now very used to seeing CGI massive robots, UFOs, Starfighter, and superheroes in space we make the assumption that the CGI is attempting to look as real as possible. This however is not true. Which is where the other answers in this sub step in.\n\nThe way light lands in space is stranger than fact, and if animators aimed to match it perfectly it would not look \"right\" with our perception of what it should look like. So animators (and colourists) maintain a \"realer than real\" approach, by using three point lighting, fill lights, reflected ambience and haze to add atmosphere. These make the shots more visually stimulating, and also help intercut with incamera shots. In short by making it less real, we as an audience can relate on a natural/shallow/primal level to what we are seeing.\n\nThis inturn leads to us seeing actual photos of real moon rocks, being hit by the actual sun (at a very difference distance to what we see on earth) as being ... well... wrong.\n\nAnyway, that's my 2 cents. Hope it was interesting.",
"I think you have it backwards. CGI looks like space, not the other way around. It's pretty easy to create \"space-looking\" objects with CGI. You have a black background, and you just add spherical, static objects. Add detail and color to get what you're looking for. Things like nebulae and light from stars are obviously more complicated, but the basics at least are some of the easiest to create in a CG environment. "
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1fz998 | the drone war in pakistan. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1fz998/eli5_the_drone_war_in_pakistan/ | {
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"text": [
"Killing people with robots is more effective than killing people with other people. /thread. ",
"Since nobody else has mentioned much, I'll go into some details. As a precursor, keep in mind that drone strikes are generally hard to track and report on, especially since they occur in areas inaccessible to media, so facts and figures will always vary from source to source. \n\n**PART 1: BACKGROUND**\n\n* Drone strikes fall under the larger category of targeted killing. That's basically when we pick out specific people to kill, then send in some people/drones/whatever to do it. The drone war began in 2004 under the president Bush, who began the program as a way to take out the top leaders from terrorist groups, and [Obama did it more](_URL_3_) during his first and second terms]. [This report](_URL_1_) shows massive escalation, but its own sources are media accounts, which can be iffy. \n\n* The legality of drone strikes is questionable. \n\n**First**, they violate the due process clause of the Constitution, which extends to non-combatants. Instead of capturing people and giving them a fair trial, drones simply remotely kill them - and the decisions are not made by judges, but by military figures. The US claims it is still at war with militant groups like Al Qaeda, but the legal parameters of what does and doesn't qualify as a terrorist organization is vague. \n\n**Second**, the official legal justification is the [AUMF](_URL_4_), a bill passed just days after 9/11 that essentially allowed the government to do whatever it wanted to stop terrorists. This bill is understandably a shaky foundation for 12 years of attacks, given that it was passed in an atmosphere of fear and broad national hysteria. \n\n* **Civilian deaths** are a huge issue. Drone strikes have a surprisingly low success rate, but even if they do work they're likely to also kill nearby civilians who were simply in the wrong place at the wrong time. Even in the best of situations, [spouses and children of the target](_URL_0_) are almost inevitably killed. \n\n**PART 2: DOES IT WORK?**\n\n\n* On the other hand, **the effectiveness in countering terrorism seems weak**. When Osama bin Laden was killed, everyone was excited and it was a huge deal. But two years later, there's no visible change in the operations of terrorist organizations. The answer might actually be worse - it is empirically demonstrated that when central leadership is killed off, terrorist organizations splinter and create more organizations for governments to track, most of which become more radicalized. \n\n[Statistically](_URL_0_), only about 1/7 (14%) of drones actually kill their targets. And only a few of these targets are high-level operatives, as opposed to random cogs in the terror machine. This means only about **2% of the time, high-level \"terrorists\" are killed.**\n\n* The majority of drone strikes target Pakistan's North Waziristan tribal area, which is where the historical roots of many terrorist programs are, and is often a place for new recruits. **However, the drone strikes only serve to inflame locals more and breed anti-US hatred.** How would you feel if flying machines came out of the sky and killed your entire family while wrecking your house? This kind of hatred, along with the image of drone strike victims as martyrs for the cause, [feeds the cycle of terrorism](_URL_6_). \n\n**PART 3: THE FUTURE**\n\n* The new government of Pakistan is not okay with this. [Recently](_URL_2_), the new PM Nawaz Sharif condemned drone strikes as a violation of Pakistan's sovereignty, which they almost definitely are. \n\n* Perhaps because of the lack of support, President Obama says [he's going to tighten restrictions](_URL_5_) on who qualifies as a target of drone strikes. Of course, the elephant in the room was civilian deaths: what happens if we create collateral damage, as we've almost always done in the past?\n\nTL;DR: I did my best to organize this, and I'll probably come back and add more stuff later. But seriously, can't you read one bullet point?"
]
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[],
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"http://www.foreignaffairs.com/articles/67939/peter-bergen-and-katherine-tiedemann/washingtons-phantom-war",
"http://natsec.newamerica.net/drones/pakistan/analysis",
"http://www.bbc.co.uk/news/world-22820208",
"http://www.cfr.org/counterterrorism/targeted-killings/p9627#p5",
"http://www.cfr.org/counterterrorism/targeted-killings/p9627#p3",
"http://www.cfr.org/counterterrorism/president-obamas-speech-national-defense-university-future-our-fight-against-terrorism-may-2013/p30771",
"http://web.law.columbia.edu/sites/default/files/microsites/human-rights-institute/files/The%20Civilian%20Impact%20of%20Drones.pdf"
]
] |
||
6qqz3e | how do online streaming services like netflix determine what shows are financially successful without traditional tv ratings and advertisements? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6qqz3e/eli5_how_do_online_streaming_services_like/ | {
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"They know exactly what shows new subscribers watch, along with what shows on-going subscribers watch. They know when they watch and how long they watch.",
"They dont share their specific view info or what they look at to determine success.\n\nobviously they know who views what, and how much they view. So if they see someone binging OITNB and not much else, they know that show is retaining a subscriber. Most situations would never be that obvious though. "
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9uv4u7 | how do people make compilation videos? | Do people just download every single videos through mp4 downloader, one by one and just pile it up? If they do then that sounds really exhausting. Or is there another method? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9uv4u7/eli5_how_do_people_make_compilation_videos/ | {
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"In most cases, yes, people download or gather all the source footage (download a movie, download internet videos from YouTube, etc).\n\nIn some cases, they record the screen during the part of their footage that they know they want. This is much better for people with limited space to work with. They might search up a memorable clip on YouTube if it’s available.\n\n\nThen, if they’re on a phone, there are plenty of apps to make compilation videos. On a computer, any video editing software will do the trick.\n\nEditing is a long and tough job. If you’re referring to compilation creators like WatchMojo, those people are paid to do that. I assure you they don’t do it because it’s fun. From my experience working with film, for every minute or two of a video that you watch, they probably spent at least 10 to 20 minutes editing. At least!"
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dfuhgm | how do we make really small things. | For example, a phone camera sensor with 20mp, that’s 20 million pixels. The size scale is so small it’s like trying to imagine the size of the universe. How do we make things so small. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dfuhgm/eli5_how_do_we_make_really_small_things/ | {
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"In terms of electronics\n\nWe got really good at making precise silicon structures. In the macroscopic world we talk about resistors and transistors and capacitors but in the microscopic world it's just a few strips on metal shaped 'weirdly' with the blackest of magic semiconductors inbetween.\n\nWe have managed to precisely remove chunks of silicon specifically filled with post transitional metals to change the electrical characteristics in specific ways. \n\nWe have managed to make a single atom function as a transistor. That is only done from hardwork, incredible research, and someone(s) crazy enough to try",
"Camera sensors, microchips, and many similar devices are made by a technique called photolithography. \n\nWhat all of these things have in common is that they are flat, and built up of successive layers, each of which is printed in a pattern. \n\nIf you've used an old-fashioned film camera, you know that a pretty detailed picture of an entire room would be shrunken by the lens down to a little 35-mm-wide rectangle of light-sensitive film. \n\n & #x200B;\n\nSomething similar happens when making microchips. A sheet of material (usually a round disk of Silicon called a Silicon Wafer) is coated with a thin layer of metal, semiconductor, insulator, or additives like dopants that change its properties. Then it is coated with a light-sensitive liquid plastic called photoresist. \n\nA system a bit like a camera lens, but using super-high-performance optics, is used to project ultraviolet light through a mask, which is basically a large transparency of the design that is being created. Masks are about the size of a sheet of paper, a bit larger. The mask design is shrunken down to a tiny square by the optics, and wherever the light hits, the photoresist becomes hard. The non-hard photoresist just washes off, and then the wafer is covered with a very detailed, small pattern of the design being produced in photoresist. \n\n & #x200B;\n\nThen, acid or a plasma beam is used to burn away the recently-added coating in all the places where there is no photoresist. Then the photoresist is removed, and the process begins again. Eventually, enough layers are built up that the thing becomes a CPU or a GPU or a camera image sensor."
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3gsmm9 | why are people upset about target's removal of gendered signs? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3gsmm9/eli5_why_are_people_upset_about_targets_removal/ | {
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"I think some people are upset because of the \"pussification\" of the US. Everything is becoming to PC. Everyone is afraid of offending everyone else. ",
"I think it's just viewed as over and unnecessary moderation. We are currently struggling with the balancing act of appeasing both those who want the whole word to be baby proofed where nothing can ever be misinterpreted as offensive and those who want things to be \"the way they used to be\" and lately it seems most decisions, or at least the louder ones, are leaning towards keeping the former group happy. This being an example of that. ",
"Most people don't actually care, but you're not hearing from those people. Instead you are hearing from the loudmouths who, if not complaining about this, they would be complaining about something else of similar unimportance. Personally, I don't think Target needed to do this, but I can't even summon a tiniest bit of care one way or the other.",
"Society is so politicized now that inconsequential details about daily life are now perceived by some as symbolizing a culture war. Gender signs on bathrooms is tapping into the idea of transsexual rights, political correctness and liberalness in general. \n\nIn short, it touches a nerve in the \"us vs. them\" mentality."
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fhrnhz | why does good weather (sunny, warm) instantly seem to improve one’s mood? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fhrnhz/eli5_why_does_good_weather_sunny_warm_instantly/ | {
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"Not down here in (North) Florida. We look outside and think \"ah shit another sunny day, I bet it's a sauna out there\"... Most of us are grateful for the cloudy, rainy, and cooler days since they tend to be much more rare.",
"There are several biological functions that are aided with the addition of sunlight. Synthesis of vitamin D and several other things. \n\nBeyond this the immune system is getting a nice break due to decrease in viruses spreading. All of these have significant impacts on mood. \n\nI can gather appropriate articles to quote if you’d like. \n\nHope this helps!",
"When sunlight hits your optic nerve it triggers the brain to release serotonin and dopamine also this is why some people experience SAD (seasonal affected disorder ) due to a lack of sunlight. It literally boosts your mood by flooding your brain with serotonin and dopamine."
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1r005x | why does the tempo of a song seem slower than you remember sometimes? | This one song which I've heard hundreds of times sounds ridiculously slow today... | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1r005x/eli5_why_does_the_tempo_of_a_song_seem_slower/ | {
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"Did you drink a lot of caffeine? \n\nI'm no neuroscientist, but I believe that when you are in a higher energetic state (high adrenaline, caffeine buzz, excited in general), your perception of time changes, and everything seems slower, like a song's tempo. In the past we played many shows where I thought the tempo was perfect, but played back a video of the performance and we were rushing the song badly because we were having an adrenaline rush.\n\nWe eventually learned that if we are super excited, like when playing a big show, we had to play a little bit slower than we feel we should, and the tempo of the song ends up right.\n\nSOURCE: Touring musician for 7 years",
" > ELI5: Why does the tempo of a song seem slower than you remember sometimes?\n\nIn all likelihood you either haven't developed the facilities for tempo-recognition very well, or you're experiencing a mental, emotional or biological process which is interfering with your ability to remember the tempo of this particular song correctly. This is just speculation on my part, but there is [evidence that auditory memory is absolute](_URL_0_), rather than subjective, particularly in regards to tempo-recognition. As such I'd reason that you're just tired, under the influence of a mild stimulant, or emotionally excited, which is interfering with your auditory memory. But if you discover in the future that at this time you were in the early stages of developing a mental disorder or a brain tumor, I hope you remember this post and choose to respond to it. I would find this most interesting... and would offer you my sympathies, of course.\n",
"There are a number of reasons this can happen. Sometimes it's you, sometimes it's what you're actually listening to.\n\nThe latter is rather easy to explain: It might be a remix of some type you've heard; perhaps a radio station has actually altered the pitch and speed either to give a distinct sound or for copy protection (ie, the source of the track can be identified this way when it's checked later).\n\nOr, it could just be that your own sense of time and tempo aren't quite as well developed."
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3d1o22 | how do people learn their native language? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3d1o22/eli5_how_do_people_learn_their_native_language/ | {
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"Mimicry and watching a lot. Parents talk, and babies listen even when we don't think they're paying attention. Sounds that get a response are reinforced, so they make them more often. Eventually parents start pointing to stuff and making sounds, so the babies pick those up along with the object association. Abstract concepts come later, mostly babies learn which sounds make mommy or daddy come running, which sounds bring food, etc."
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mmdsj | the milgram experiment and its singnificance to psychology | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/mmdsj/eli5_the_milgram_experiment_and_its_singnificance/ | {
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"To understand the Milgram experiments (there was more than one) you need to remember that it happened shortly after WW2. Psychologists (and most people) were trying to work out how humans could behave in the way the Nazis did. Milgram's experiments looked at the part of authority in doing evil.\n\n**How the experiment worked**:\n\nA participant was showed into a room with a big knob attached to a computer. A research assistant (wearing a lab coat - this changed in later experiments but it was considered important in the first experiment) explained that the experiment was on how punishment affected learning. The participant was instructed that they were to ask questions to another participant, through an intercom, who was on the other side of a wall and if the other participant got the answers wrong, they were supposed to use the knob to give them an electric shock. They were also told that each time the answer was wrong, the shock should get stronger. The experiment then began with a confederate (research assistant pretending to be a participant) answering questions. If the answer was given wrong, the confederate would scream in pain. \n\nIn the first experiment 65% of the participants gave the highest level shock (marked as 450 volts).\n\n**What that means**:\n\nThe reason these results were so significant is that outside of that setting it would be very hard to convince someone to give another person a 450 volt electric shock. Milgram believed (and later experiments supported this) that the authority of the researcher was the reason that the person was able to do something so unconscionable. ",
"He showed that people would obey an \"authority figure\" who instructed them to perform acts that conflicted with their personal conscience.\n\nThe basic results came down to 2 possible explanations\n- if unsure (especially in crisis) trust the group to make a decision\n- they're not responsible for their actions, as they're following instructions from higher up.\n\nIt was also used as a possible explanation to nazi's killing jews during wwII, and whether they had the capacity to say no, or they were willing participants.\n\nIt also raised questions about the research **ethics** of scientific experimentation because of the extreme emotional stress. It would never pass an ethics committee now.\n",
"I learned this in psychology today... Do you perhaps live in the lower mainland area of BC?",
"It is significant because it demonstrated something that was wildly contradictory to the expectations of most of the research field at the time. Milgram originally developed the experiment following the events of WWII, where Nazi soldiers and others who inflicted many atrocities, when asked why they did it, responded that they were simply \"following orders\". While most vilified them for what they had done, Milgram attempted to find an explanation for their seemingly evil behaviour (similarly-famed social psych and personal friend of Milgram's, Philip Zimbardo, accurately summed it in his own research, saying that it was not a case of a few bad apples, but of a bad barrell).\n\nI've read a lot about this experiment (Milgram is my absolute hero of social psych), and he asked several prominent researchers how many participants they thought would deliver the highest shock level. From memory, I think most said 1% or less, a figure they said would match the proportion of sadists and psychopaths in the sample population.\n\nMilgram was able to deliver strong and unexpected results, and the Obedience to Authority experiments*, together with Zimbardo's Stanford Prison experiment, gave a social psychological explanation of seemingly evil behaviour, a very significant issue at the time (and today still).\n\n(*Milgram hated for them to be called \"the Milgram Experiments\", feeling that it belittled the rest of his works)",
"To understand the Milgram experiments (there was more than one) you need to remember that it happened shortly after WW2. Psychologists (and most people) were trying to work out how humans could behave in the way the Nazis did. Milgram's experiments looked at the part of authority in doing evil.\n\n**How the experiment worked**:\n\nA participant was showed into a room with a big knob attached to a computer. A research assistant (wearing a lab coat - this changed in later experiments but it was considered important in the first experiment) explained that the experiment was on how punishment affected learning. The participant was instructed that they were to ask questions to another participant, through an intercom, who was on the other side of a wall and if the other participant got the answers wrong, they were supposed to use the knob to give them an electric shock. They were also told that each time the answer was wrong, the shock should get stronger. The experiment then began with a confederate (research assistant pretending to be a participant) answering questions. If the answer was given wrong, the confederate would scream in pain. \n\nIn the first experiment 65% of the participants gave the highest level shock (marked as 450 volts).\n\n**What that means**:\n\nThe reason these results were so significant is that outside of that setting it would be very hard to convince someone to give another person a 450 volt electric shock. Milgram believed (and later experiments supported this) that the authority of the researcher was the reason that the person was able to do something so unconscionable. ",
"He showed that people would obey an \"authority figure\" who instructed them to perform acts that conflicted with their personal conscience.\n\nThe basic results came down to 2 possible explanations\n- if unsure (especially in crisis) trust the group to make a decision\n- they're not responsible for their actions, as they're following instructions from higher up.\n\nIt was also used as a possible explanation to nazi's killing jews during wwII, and whether they had the capacity to say no, or they were willing participants.\n\nIt also raised questions about the research **ethics** of scientific experimentation because of the extreme emotional stress. It would never pass an ethics committee now.\n",
"I learned this in psychology today... Do you perhaps live in the lower mainland area of BC?",
"It is significant because it demonstrated something that was wildly contradictory to the expectations of most of the research field at the time. Milgram originally developed the experiment following the events of WWII, where Nazi soldiers and others who inflicted many atrocities, when asked why they did it, responded that they were simply \"following orders\". While most vilified them for what they had done, Milgram attempted to find an explanation for their seemingly evil behaviour (similarly-famed social psych and personal friend of Milgram's, Philip Zimbardo, accurately summed it in his own research, saying that it was not a case of a few bad apples, but of a bad barrell).\n\nI've read a lot about this experiment (Milgram is my absolute hero of social psych), and he asked several prominent researchers how many participants they thought would deliver the highest shock level. From memory, I think most said 1% or less, a figure they said would match the proportion of sadists and psychopaths in the sample population.\n\nMilgram was able to deliver strong and unexpected results, and the Obedience to Authority experiments*, together with Zimbardo's Stanford Prison experiment, gave a social psychological explanation of seemingly evil behaviour, a very significant issue at the time (and today still).\n\n(*Milgram hated for them to be called \"the Milgram Experiments\", feeling that it belittled the rest of his works)"
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5nyxg9 | why did it take so long for humans to realize that there was a relationship between hygiene and health? | If I'm not mistaken, even a couple hundred years ago people in Europe were dumping their sewage in the streets and what not. Didn't some civilization cement the idea that bad hygiene correlated with bad health? I know there were some practices that go way back, such as the Indus Valley civilization, but why didn't it stick until just a couple hundred years ago? Didn't people realize that operating on wounds with dirty hands would lead to infection, etc? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5nyxg9/eli5_why_did_it_take_so_long_for_humans_to/ | {
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"What is infection? Are you trying to tell me that tiny invisible life forms live in the water and on every surface are the things that make us sick? These things we can't see are the source of our problems? Yea right. Shut up and pray to god harder if you want to be well.",
"Until the discovery of germs, the transmission of disease was poorly understood. People thought you just spontaneously got sick. Also, there was the thinking that cleanliness was related to social class. To suggest a doctor needed to wash his hands was to insult him, his upbringing, and his entire lineage.",
"Because for most of human history, it wasn't necessary.\n\nWhen you live in a village of fifty people, you can throw your trash in a pile out back, because there isn't that much of it. Especially if you are nomads who are going to pack it in a few months later.\n\nFor most of human history, that was much more common than streets or operations. Only when we started living in cities did sanitation become a concern. But even then, when you are struggling to feed everyone, sewers become a luxury.",
"Europe was way behind for no reason I can imagine: they didn't understand how to have hot running water when 1000 years earlier Rome had it just fine."
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22ld57 | the thought process behind deciding different fines for different crimes. | I'm studying human trafficking and in many countries the fine for drug trafficking can be up to a hundred times the fine for trafficking a human. Are fines decided on some sort of scale? What is stopping us from making fines so high that they are more prohibitive? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/22ld57/eli5_the_thought_process_behind_deciding/ | {
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"Speaking only for the U.S.-Fines are usually determined by statute, a.k.a. legislature made law. They're not subject to any calculation or matrix to determine how severe they should be for any particular crime (usually, though things like speeding do use some calculation depending on the degree of the offense). \n\nAs to what stops them from being made so high as to be severely prohibitive. Primarily the 8th amendment's \"cruel and unusual punishment\" clause. Extremely high fines for lesser offenses (as determined by a judge) can be thrown out on 8th amendment grounds. That being said, it's not often it happens (even with jail time). \n\nSource: 2 semesters of Con Law in law school."
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6orlp2 | how did we come to agree that working 8 hours a day for 5 days a week is the norm? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6orlp2/eli5_how_did_we_come_to_agree_that_working_8/ | {
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"You can thank unions for that. Before they stepped in, we worked 7 days a week with no cut-offs or OT. ",
"Eight hours of sleep, eight hours of work, and eight hours of whatever, it was the most fair.",
"That's all thanks to unions - before people started unionizing, there weren't really rules on workers' rights - people could be worked until they collapsed, every day... or maybe with Sunday off for church.\n\nOnce industrial workers started unionizing, they had enough pull to work out a deal that's mostly held up ever since: two days of rest, 8 hour days. The 8 hour days because things could be easily split: 8 hours work, 8 hours sleep, 8 hours for whatever else you want to do.",
"Yer not alone in askin', and kind strangers have explained:\n\n\n1. [ELI5: Why is \"40 hours a week\" considered a full time job? ](_URL_0_)\n1. [ELI5:Why do we work 5 days per week? ](_URL_1_)\n1. [ELI5: Who decides how many days we work per week ? If everyone (I mean everyone) worked 3 days a week, what would be different ? Is the number of work days and hours a natural process ? ](_URL_3_)\n1. [ELI5: Why do most people work 9-5, 8 hours a day? ](_URL_4_)\n1. [ELI5: Who decided that 8hours a day should be the norm for a normal working day, and why? When did it come about? ](_URL_2_)\n",
"It's quite correct to thank the unions for the great strides in pay and conditions since the terrible times of the industrial revolution. It amazes me, however, that many of the people I work with think that somehow these advances in their rights are set in stone and the need for collective bargaining is over. Australia has been at the forefront of many important social and workplace changes. South Australia was the first to give women the vote (Our cousins in New Zealand were the first country) and we were pioneers of the 40 hour week. One other concept we don't hear much of these days but originated here is that of the \"living wage\". That is the minimum wage was determined by what was needed to support a typical working class family. I think as we live in these times of increasing gaps between rich and poor as well as a shrinking middle class it is important to remember we are part of a society and what happens to all citizens is important. Failure to provide decent working conditions and pay for the low skilled impacts our welfare system, crime rates, addition rates, domestic violence and so on. Some companies in the U S pay staff so little for full time work that they have to simultaneously receive social security benefits. They pitch wages at a level which makes it possible and then show staff how to apply. This is cynicism beyond belief particularly as these companies do everything they can to avoid tax and the owners are now doubt fans of small government. It is true that rich Americans have an fine tradition of philanthropy but that is no substitute of proper progressive taxation system to find those societal obligations that the free market simply cannot or will not. There is a common belief amongst many that a country should be run like a business and this is a great fallacy. Yes the expenditure should be well targeted, value for money, accountable and transparent but the similarity ends there. The objectives of government are quite different to those of business. I would add that on Going revelations of business practices reveals that they are not the paragons of free market virtue that would make them in some sense worth emulation. They are often an embodiment of all the full spectrum of human vice but without the individual responsibility of a human. So rarely does one see a company director go to prison for corporate behaviour that may have killed injured people, ruined the environment, avoided tax, engaged in market rigging and so on. It's a real problem and their influence on the political process is no less reprehensible. \n\nSo be aware and be grateful for the working conditions and pay that have been dragged from the employer since the free for all of the industrial revolution but don't for a moment think that there are not powerful forces continually trying to erode them. Also remember also that the only effective way of countering this claw back is through the ballot box and through collective bargaining."
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"https://www.reddit.com/r/explainlikeimfive/comments/35pgef/eli5_why_is_40_hours_a_week_considered_a_full/",
"https://www.reddit.com/r/explainlikeimfive/comments/3q9rp3/eli5why_do_we_work_5_days_per_week/",
"https://www.reddit.com/r/explainlikeimfive/comments/4ayhok/eli5_who_decided_that_8hours_a_day_should_be_the/",
"https://www.reddit.com/r/explainlikeimfive/comments/5z48tj/eli5_who_decides_how_many_days_we_work_per_week/",
"https://www.reddit.com/r/explainlikeimfive/comments/111s1u/eli5_why_do_most_people_work_95_8_hours_a_day/"
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4nxgkk | when a car traveling 50mph hits another car head-on also traveling 50mph it hits it with the force of a car hitting a brick wall at 50mph. why isn't it more forceful? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4nxgkk/eli5_when_a_car_traveling_50mph_hits_another_car/ | {
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"If both cars are a similar mass, then they will both stop. Both cars will have a speed change of 50 MPH. The change in speed is what causes the forces in a crash, so coming to a stop by hitting a wall, and coming to a stop by hitting a car are the same. If a 50 mph car hits a 50mph 18wheeler, the car won't stop. The car will be pushed backwards because the truck weighs more, and it will have a larger than 50MPH change in speed. The truck will not completely stop in this collision, and it won't have as bad of a crash as if it hit a wall.",
"/u/DeltaVZerda and /u/GenXCub responded well, but if you still can't get your head around it, then this might help:\n\nThere is twice the carnage, but it is \"divided\" between the two cars equally. (Whereas in the wall hitting scenario, we presume that the wall did not move at all and the car took all the damage.)",
"You're correct that a head-on collision with a moving car is more forceful than hitting a parked car.\n\nThe problem is that a brick wall is actually more like the moving car than the parked car. Here's why:\n\nIn the head-on collision, you suddenly come to a complete stop.\n\nHitting a parked car, the two of you will slide, at about half your original speed. This makes the impact less forceful because you don't lose as much speed.\n\nHitting a brick wall, you suddenly come to a complete stop.\n\nIf you built a wall that could slide, then it would be more like hitting a parked car. But walls aren't usually built that way."
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7zrkfd | why is it that physically intensive manual labor is known to cause permanent injuries through wear-and-tear, but frequently working out/weight lifting isn't? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7zrkfd/eli5_why_is_it_that_physically_intensive_manual/ | {
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"Actually it is. Lots of serious athletes have substantial wear-and-tear on their bodies. However, modern athletes have the ability to tune their workouts to minimize this, while when it's your job, you don't get to choose which activities to skip.",
"Part of it has to do with repetition. That's one reason why cross training is recommended. Many forms of manual labor jobs require many of the same motion over and over for hours a day. Most people don't work out for 8 hours a day, and also they do more variety of movements. ",
"Frequently working out and lifting weights is known to cause permanent injuries. This is very well documented. "
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2w9trg | when i eat chips in a quiet room, does it sound as loud to everyone else in the room as it sounds to me? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2w9trg/eli5_when_i_eat_chips_in_a_quiet_room_does_it/ | {
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"No. Sound is vibration in air, but the eardrums which detect that sound are anchored in your head, which is attached to your jaws. The vibration can conduct straight through the bone into your ears and be heard much more loudly than others would hear.\n\nBut close your mouth anyway."
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9g60xo | why does metal music seem to have so many more subgenres than other styles | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9g60xo/eli5_why_does_metal_music_seem_to_have_so_many/ | {
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"Well in rock I'll say a lot of bands who dont fit in with any certain genres will just go by the genre of alternative. Look at the Red Hot Chili Peppers for example, they're classified as Rock, funk, and alternative for all their songs that just don't fit into a defined genre. ",
"I think there are two factors. Metal is a very technical genre which means that those technicalities are used to define and differentiate subgenres. Also because metal is not a mainstream genre, or a genre that ever shows up in popular music, it is mostly listened to by people who have more than a casual interest in metal, which facilitates the discussion and labelling of different genres. ",
"Around 95 elements on the periodic table are metal, and only a few are rock. None of the elements are folk.",
"Electronic music may have more subgenres than Metal. Like, lots more: [_URL_0_](_URL_0_)",
"There’s like 1billion electronic music sub-sub-sub-genres. It can even be exactly the same but just a different bpm and they give it a new name",
"Some people like to overemphasize genre over a bands sound, or bands that simply sound a little similar. It’s fun to kind of categorize music in our imaginations. It holds little scientific definition, but it’s how we organize personally. Rarely does anyone agree. ",
"If I'm not mistaken, rap music also has a ton of subgenres, at least as many as there are major cities in the US. Metal has a lot of subgenres because most metalhead have some elitist view of their music, and therefore they have to separate them from what they do not consider being true metal. In order to do so, they need labels to apply, so \"them\" and \"us\" can be easily known. ",
"Every genre has a ton of sub-genres that no-one knows out cares about outside the very \"passionate\" niche. Nothing is unique.",
"Metal is really best defined by \"...loud distorted guitars, emphatic rhythms, dense bass-and-drum sound, and vigorous vocals\" ([From Wikipedia](_URL_2_)). As you can imagine, that can cover a wide variety of music. Is it slow and powerful or fast and aggressive? Are the \"emphatic vocals\" shouted, growled, or sung operatically? Does it have wicked guitar solos or crushing breakdowns? Or all of the above?\n\nAnd since metal isn't exactly a very mainstream music, a lot of very musically different bands get labeled by the public as \"metal\". The additional subgenres help to clarify which specific type of metal you're talking about. Personally, I like uptempo music with virtuoso guitar solos, so I would say I like thrash metal (like [Metallica](_URL_3_)) or power metal (like [Dragonforce](_URL_3_)). And even between those two samples, you can hear differences: thrash metal is more aggressive while power metal is more operatic.\n\nI'd say metal fans are more passionate about subgenres because metal is on this weird edge of society where everyone can identify what *is* metal, but not what *kind* of metal it is. So you get situations where [The Simpsons call Judas Priest death metal instead of regular heavy metal](_URL_4_). For comparison, [this is Judas Priest's \"Breakin' the Law\"](_URL_0_), while [this is what death metal sounds like (\"Hammer-Smashed Face\", by Cannibal Corpse](_URL_1_). It's like when your mom comes in on you watching Sailor Moon and calls it Dragon Ball.\n\nYes, it gets crazy sometimes when you have to differentiate between the sub-sub-subgenres, especially when so many bands combine different elements from different types of metal. But, at least with the more popular subgenres, it's a helpful way to classify metal music."
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"https://www.youtube.com/watch?v=aAITxlCsj4Y&t=2371s",
"https://www.theguardian.com/music/2014/jan/14/simpsons-apologise-judas-priest-death-metal"
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bhgxi6 | how does debt collecting work? how do debt collectors make money by buying more debt? | I honestly tried researching this, but it is so confusing. It doesn't make sense for collectors to buy more debt. What now? I bought 5k in debt for 25$, now I'm 5,025$ in debt now??? Someone explain I am confusion!
Edit: Thanks to everyone who commented, I now know how debt collecting works :) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bhgxi6/eli5_how_does_debt_collecting_work_how_do_debt/ | {
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"You don't go 5k in debt by buying it. You are buying the right to*collect* that debt. \n\nE.g. Debtor owes seller $5,000. You buy the debt from the seller. Now the debtor owes *you* $5,000.",
"When you buy debt, you aren't buying the debt from the debtor, you are buying the debt from the lender. In this sense the debt is just money that you haven't been paid yet. If you buy 5k for 25$ you are down that 25$, but once the person pays back their debt you get that 5k from the debtor. There is always the chance that they dont pay you back, in which case you are now down 25$ forever, so there is a bit of risk, but for the most part you can make a good deal of money buying debt.",
"Companies sell debt often at pennies on the dollar. So if you owe the bank $5000 and you dont pay. They may not have time to go after you. So they cut their losses and sell your $5000 debt to a debt collector who buys it for maybe $500. But you still owe the $5000 plus whatever interest has accrued. So they have a chance to profit $4500 plus interest if they get you to pay. At this point your debt could be passed from collector to collector. Each time the cost to purchase the debt goes down while your amount owed goes up and up. Eventually a collector may decide to sue to get the money resulting in your wages being garnished.\n\nIn June 2016 john Oliver bought 15 million in medical debt for only 60 thousand dollars. Then promptly forgave the debt, wiping it clean. They essentially gave away 15 million dollars, equating to the largest cash giveaway in tv history.",
"You owe Bob $20,000. But he’s given up collecting from you because you keep giving excuses why you can’t pay yet. Jim offers him $5000 for the rights to your debt... hey it’s better than $0 and Bob wants to go on vacation, so having that $5000 now helps. For Jim, anything beyond the $5000 he can collect is profit, so if you eventually pay $10,000 he’s doubled his investment.",
"(the numbers in the example are...not even good guesses since I have very little insight in the industry. But try to disregard that bit.)\n\nImagine for the sake of the reasoning that a phone company has 500 customers who are not paying. For simplicity sake, they have all had their services disconnected after totalling $100 in debt, each. The phone company is out $50000, and want to get back as much as possible of it.\n\nWhat they do is that they sell the debt to a debt collector. But, the debt collector knows from experience that if they are lucky, they'll be able to get back...maybe half of that money. Ever. And then they want a profit; they are buying the right to collect on the debt for $20000.\n\nThe business model of the debt collector is, obviously, to get more than 200 customers to pay back their debt in full. Because it's only then that they make any money. 201st customer to cough up, and they are in the plus. Not that much, but some. Their goal, of course, is that they want to get to those 50% back, so that they are up $5000. Which, you know, definitely makes it worth the trouble to send out 500 letters where you kindly ask people to man up and pay their bill.\n\nSome customers will not pay, and maybe it's worth some trouble driving by their houses and flat out tell them to kindly start paying. Some people do have honest trouble with getting their mail, the debt is long forgotten and all that. And those will immediately fix their shit once you come see them.\n\nThe trouble are those people who are never paying. Who you can talk to daily for weeks, because they are kind of not really worth the trouble. But you know that already, because about half the debt is gonna be like that.\n\nThe trick for the collector is to collect several debts at the same time. Because, uh, people who are not paying are pretty often not paying to anyone at all. Then, when you send out the guy to knock on doors, you just give him the entire pile of papers in one go. His work is mostly to drive around and find the right address, so if he is able to serve more than one paper at the same time, then he is more efficient. (Jay!)\n\nBut...still. The reason that the bills are piling up *may* have been some kind of clerical error with the mail, change of addresses and such after a move. And when you actually find someone who had no intention not to pay, but just ain't aware of their debt, then it's worth the entire days effort at driving around and tracking down people.\n\nMost people are just trying to scam the phone company on their money. But some debts are honest mistakes. That are just hard to track down and get fixed. Find one of those, and the collector gets their money back.\n\nAfter that, the collector just piles up everything they have bought in your name. Bides their time. And hopes that they may stumble upon you some other time. Perhaps swing by your house again when they are serving a letter to the neighbour one street over a few months later, and so on.\n\nAnd, most importantly, they learn that they are never again bailing you out of your debt again since they can't get hold of you. The next time a phone company tries to sell the collector debt in your name, they are denying the transfer. Or buying it really cheap. Or maybe they are saying *\"you get to keep that debt, but we don't mind serving your papers too if we manage to get hold of him. If we do get him to sign your papers, we want $30.\"* Which, uh, for the phone company is a chance a lot better than no chance, so they'll probably take it."
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f69yym | why do nutritionists look at "daily nutritional value" when historically humans did not have access to a variety of nutrients? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/f69yym/eli5_why_do_nutritionists_look_at_daily/ | {
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"Historically we lived in caves, and trees before that, but we don't set our building regulations based on that. Times have moved on. Most people, in the developed world anyway, do now have access to a variety of nutrients.",
"What do you mean, we haven’t had access to a variety of nutrients? Of course we have, even if not in the same forms or from the same foods as today. What exactly do you think we were missing?\n\nHumans are omnivores. We’ve always been able to eat a lot of different kinds of food, as and when they became available to us. As we developed food preservation techniques like fermentation, smoking and so on, “available” became a longer and longer stretch of the year for a lot of foods.\n\nShit, you can live almost exclusively off potatoes and dairy if you really need to - this was the staple diet of Irish country life before the potato famine, and it made them notably taller and stronger and healthier than most of the rest of Europe...until the potato crop collapsed - since everything the spuds won’t provide, the dairy does.",
"The purpose of these recommendations is to inform modern consumers who want healthy, nutritious food. It is not to preserve cave-man consumption patterns. We have paleo diet books for that."
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1g5w9b | what did early humans do on an average day? | I'm talking 40,000 years ago in Europe. Obviously they hunted and gathered but life was brutal, what would they do for fun?
A typical day in the life of an early European. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1g5w9b/eli5_what_did_early_humans_do_on_an_average_day/ | {
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"Life wasn't \"nasty, brutish and short\". According to the latest research, hunter/gather societies had massive amounts of free time. If you go back to just the Medieval era, the so-called \"peasants\" could hardly be persuaded to work (for money) for more than an hour or two a day, because they met all their own needs via their own hands (farming, housing, etc.). I don't have references to hand as I'm on my mobile. \n\nOut tech-heavy life--and our capitalistic, corporate-driven lifestyle--isn't easy by any stretch, since we spend 8 to 10 hours (1/3 of our precious life) working for someone else for money to pay for all these nifty pointless gadgets. Life was simple in the distant past: eat, sleep, sex, storytelling, exploring, just \"being\". (This is a pet peeve of mine: that this technological life is \"better\"... It all depends on your definition of \"better\". :-)"
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bkfvqg | how is code, compiled down to machine code (1s and 0s) changed to voltage? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bkfvqg/eli5_how_is_code_compiled_down_to_machine_code_1s/ | {
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"Well it's not really ELI5, but it boils down to the transistor, which is an electronic switch.\n\nA transistor has an input, a control, and an output. As used in digital circuits, these are binary, having only two states, on or off.\n\nSo, you can wire up this switch in a few ways. \n\nOne is where if the control is 1, the output is the same as the input. If the control is 0, the output does nothing. This is called a buffer. \n\nThe other is the opposite, where if the control is 0, the output is the same as the input. If the control is 1, the output does nothing. This is called an inverter.\n\nUsually we tie the output to 0 through a weak resistor so that if the output is doing nothing, it defaults to 0.\n\nFrom these two types of transistors, we can build a general purpose computer by combining them in ways to create logic circuits. But you need a lot of them.\n\nAt the next layer up, we create devices called gates. \n\nThe first is the AND gate. You put two buffer transistors A and B in *series,* where the output of A is tied to the input of the B. Also tie the output of B to a weak resistor to 0, or logic 0 and tie the input A to 5V, or logic 1. Now the only way to get 5V on the final output of B is if it passes through both buffer transistors, meaning that both controls of A and B are on, or at 5V or, digitally, at 1. We say that the output is 1 if both control A and control B are 1. If either is off, then the weak resistor pulls the output to 0.\n\nLet's set that AND gate aside and make an OR gate. This time A and B are wired in *parallel* where both of their inputs are 1 and are tied together, and both of their outputs are tied weakly to 0. Now, if either control A OR B is on, they will provide a 1 to the output. Otherwise, the resistor pulls the output to 0.\n\nWhat can we do with that? Well we can do some interesting things when we tie gates together. If there are no loops, it is called a combinational circuit where the outputs rely only on the inputs. \n\nSuppose you wanted an output to become 1 only if the input bits are 6, or 110 in binary. You connect the first 2 bits (11) to an AND gate, and the third bit to an inverter. Then connect the output of the AND, and the output of the inverter to another AND. In this case, the first AND is 1 only if the first 2 bits are both 1, and the inverter is 1 only if the third bit is 0. The second AND is 1 only if the first AND and inverter are both 1. So you have (1 AND 1) AND (INVERT 0) which gives you 1 only if the inputs are 110. \n\nThis is called boolean Algebra, named for a guy named Boole, as it goes. By combining gates you can come up with very complex controls, for example, to add numbers, or turn on circuits by decoding the binary format of instructions. In a computer there is an Arithmetic Logic Unit (ALU) that can add, subtract, shift and otherwise manipulate data. For the instructions, you have a microcode unit that decodes instructions to route data around and control the ALU.\n\nThere is one last thing, memory. For memory, you put loops in the combinational circuits and what is known as a clock signal. The loops will cause feedback in the gates inputs and the are wired with other gates to the clock so that they only react to their inputs when the clock is 1, and freeze when the clock is 0. They may also be enabled or disabled with other inputs that may be control signals or outputs of the ALU calculations. What this means is that they can store a bit until they are allowed to change it based on new input and a write control signal which is just another bit. These are called sequential circuits because changes flow through it in steps, or sequences, as the clock toggles back and forth between 0 and 1.\n\nSo now you can have what are called *registers* in the processor to hold numbers to present to the ALU, and capture the results, to be stored elsewhere or rerouted back into the ALU for more computations.\n\nThat's the very basics. For a good ground up hand holding, pick up Charles Petzold's book, *Code*. It will walk you from light bulbs to assemblers, and it's a short hop from there to compilers.\n\nIn reality, of course it's more complex. For example, Boolean Algebra states that you can build any combinational circuit only using a gate called a NAND gate (AND with an inverter on the output), because you can build any of the other types with NAND gates. SO, you only have to use one type of gate to build your functions. Programmable logic devices (PLDs) do this."
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4rie6y | how turing machines work, what they're for, and how they relate to the busy beaver game. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4rie6y/eli5_how_turing_machines_work_what_theyre_for_and/ | {
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"A Turing Machine is an *abstract model* of a computer rather than a *practical implementation*. While some have been built for entertainment purposes, they're completely impractical for actually performing calculations. Their longstanding popularity lies in the fact that they're incredibly simple to reason about and use as the basis for mathematical proofs of algorithm complexity (trust me - if you ever worked with Lambda Calculus or Partial Recursive Functions, you'd wish for having a TM again).\n\nShort version is that you have an infinite tape. Along this tape you can write symbols (doesn't matter what they are 0/1 or a/b are popular, mathematically you can prove that having more symbols doesn't let you solve more complex problems) or overwrite them. This tape is the TM's \"memory\". A TM also has a logic unit that can make simple decisions (it's a finite state machine) based on the contents of *the current character under the tape* - it can rewrite the character and/or choose which direction to move along the tape.\n\nA [finite state machine](_URL_0_) is an *even simpler* model of computation. It doesn't even have memory. All it has a set of \"states\" it can be in and rules for moving between those states based on a single character of input.\n\nIt can be proven that the Turing Machine is capable of solving all problems that any normal computer can solve. Trust me on this one - it's graduate level CS/mathematics to get through the proof.\n\nNow that we have the TM out of the way, the Busy Beaver \"Game\" is an intellectual exercise in which you try to get a Turing Machine to write out the longest possible string of 1s on its tape *while still eventually terminating*. This means you can't just put it in an infinite loop spewing out characters, there has to be logic behind it.\n\nThe Busy Beaver \"Game\" has been of interest to computer scientists for decades. They like Turing Machines. They also like looking at whether or not programs terminate (this is called \"computability\"). It's just another way to explore the limits of what can & can not be computed.",
"A Turing Machine is a mathematical object, an abstract object, like an integer. It's not a machine in the sense that you think. They're used for establishing the basis of computation and therefore figuring out what's computable or not.\n\nI'm not familiar with the Busy Beaver game so somebody else will have to answer that for you.",
"A Turing machine isn't a thing you can buy at a store. It is a mathematical model of a computer, an attempt at the simplest possible model that can still do everything a computer can do.\n\nThe machine consists of what is called a finite state machine and an infinitely long tape that can be read, written to, advanced, and rewound. Very roughly, a finite state machine a set of computer instructions that read input and control the tape.\n\nThe busy beaver game illustrates how even very simple Turing machines can exhibit complex behavior. The object of the game to write the longest series of 1's possible onto the tape, then **stop**...no infinite loops allowed.\n\nWith only two states (think instructions) in your FSA, you can get to four 1's. By four states, you can get to 13, and at five, it jumps to over 4000. Then at six it jumps to a huge 10^(18267), and have that we don't really know what the limit is.",
"**How it works:**\nImagine you're standing on a *Sidewalk* with a *Bag of Rocks* and a *Rulebook*. As you walk along this sidewalk the Rulebook will tell you to place a rock on the ground, or maybe pick one up. Sometimes the Rulebook will tell you to walk backwards and put rocks in places you might have missed.\n\nEventually the Rulebook will tell you to stop and on the sidewalk will be a pattern of rocks. The pattern might be a big number, or a coded message, or anything depending on the rules in the Rulebook.\n\nIn some cases the Rulebook will get caught in a loop and you'll keep walking forever placing and picking up rocks.\n\nAll of this is basically one big Turing Machine.\n\n**What they are for:**\n\nThey can be used for doing calculations. For example, if you wanted to calculate 4\\*3, you could place a row of 4 rocks on the sidewalk, then a space, then place 3 more. If you have the right rulebook and you follow it exactly, then you will end up with a neat row of 12 rocks (4\\*3).\n\nComputer scientists have found anything a super advanced computer can calculate, a Turing Machine can too. They are mostly used as a teaching tool to show that you don't need a fancy computer or programming language to run fancy algorithms.\n\n**Busy Beaver game:**\n\nThe challenge is to write a Rulebook that will place as many rocks on an empty sidewalk as you can without getting into a loop. The trick is, you will be limited to a set number of rules."
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20et4y | what is vegetable oil ? and why do some plants have it and some don't | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/20et4y/eli5what_is_vegetable_oil_and_why_do_some_plants/ | {
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"Vegetable oils are triglyceride's (sorry don't know how to make that any simpler, its oils) from plants. Most if not all vegetables have triglycerides, but some have it in more abundance or more extractable forms. ",
"Oil is a type of fat. Plants are like animals in that they store energy as fat, and some species tend to have more fat than others. Some plants have so much fat that we can squeeze it out of them and bottle it, and that's vegetable oil."
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7h7fcy | fandom to a particular sports team. | I watch sports and I like individual athletes or wish teams in my city do well. If someone is a fan of a team that is in/near their city or their past city, I understand that. What's more perplexing is decades or life long fandom to a specific team name - not to an era of players, not to a coach, but to the entity, which may not even be near where that person lives. What motivated someone to be a long time fan of a sports team? Why does someone remain to like a team when the team could be composed of entirely different players, coaching staff, or even location as before? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7h7fcy/eli5_fandom_to_a_particular_sports_team/ | {
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" > What motivated someone to be a long time fan of a sports team? Why does someone remain to like a team when the team could be composed of entirely different players, coaching staff, or even location as before?\n\nThere's a whole ton of research on the topic, but it basically boils down to people like being in groups/tribes. It makes them feel like they \"belong\" to something that's bigger than them.\n\nIt turns out it still works even if they're far away.\n\n > Why does someone remain to like a team when the team could be composed of entirely different players, coaching staff, or even location as before?\n\nEven if each generation changes, the entity that makes up the \"team\" still has it's own identity. In the same way that NYC is still NYC even though the people originally living there are long dead. There's still a memory/rituals etc that is attached to the city."
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27r2tc | why does recording in 4k and downsamping to 1080p give better quality than just recording in 1080p | Saw someone say that in the comments to some youtube video. If it isn't true, please let me know. :) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/27r2tc/eli5_why_does_recording_in_4k_and_downsamping_to/ | {
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"Noise averaging. By downsampling you get rid of noise.",
"Is it possible that the average camera capable of recording 4k video is higher quality than one capable of only 1080p? I can imagine that being the case, depending on what YouTube sources we're talking about. For example, a home video camera recording at 1080p is not going to match a Red Epic at 4k.",
"4k has 4x as many pixels as 1080p, when you downsize, you average 4 pixels into a single pixel. \nAny noise or incorrectness/pixel is 1/4th of the result, instead of the whole result.\n\nSay you have, in 1080p, a single pixel of noise. \nAnd in a 4k video, you also have a single pixel of noise \nThe pixel in the 4k, is 1/4th as significant, and as such, doesn't have as great an effect.\n\nSo when you downsize (average), those 4 pixels become one, and that pixel is 1/4th noise, instead of entirely noise\n\nThis is why, even though both videos have the same number of pixels \nthe one downsized from 4k will appear sharper",
"Here are a couple of examples I whipped up to help you visualise: one little 600x600 pixel picture downsized to 25% size.\n\n[Raw pixel resize, no downsampling](_URL_1_), where the image is \"dumbly\" crushed down into bigger pixels, just like if it were rendered at the display resolution.\n\n[Bilinear downsampling](_URL_0_), where a smarter algorithm interpolates the nearest neighbour pixels, so the displayed (smaller) image retains more information from the rendered (bigger original) image.\n\nAs you can see, it's most visible with sharp edges between different colours.",
"It's like comic books. When they draw comic books they're usually GIANT pictures that get reduced to TINY frames to give better picture quality. It's exactly like that. There's more information.",
"Also, for youtube specifically, if you select the 4K video stream and play it on a 1080p monitor, you're getting a higher bitrate than the 1080p stream from youtube. This will increase your video quality every so slightly, but is technically unrelated to supersampling. ",
"An image in a video is made up of luma information (grayscale) and chroma information (colours). \n\nA 4K image has 3840 x 2160 pixels, but only really in black and white. As the human eye is much more perceptive to changes of brightness than colour, we can save resources by using what's called Chroma Subsampling. Most videos are encoded using a 4:2:0 sampling ratio, which pretty much means for every 4 pixels you have 1 pixel of chroma information. So a 4K image really only has 1920 x 1080 worth of colour information. (The same goes for Bluray, 1920x1080 luma, 960x540 chroma). Now you can change this with different encodes, but seeing as the source is usually a Bluray or a consumer camera, or something similar, you are never going to have 4:4:4 chroma Subsampling.\n\nGet a 4K video and downscale that to 1080p on a 1080p display though... You have a true 1080p image.\n\nSo in the end, don't buy a 4K TV. Buy the best 1080p TV you can afford and put 4K content into it.\n\nedit: Damn. Didn't see this was about YouTube videos :( it's past my bedtime\n",
"debayering. On a camera sensor, each pixel only reads one colour (in a g-r-g-b pattern) and then the other two colours for that pixel is interpolated from surrounding pixels.\n\nwhen you downscale 4k you get on average two green, one red and one blue sampling for each 2k/hd pixel which will result in a higher quality image."
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1qttkg | how do i "read" stocks? | Such as, how to read the graphs, how the number reflects how good/bad their stock is, etc. :( I dont understand anything about stocks. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qttkg/eli5_how_do_i_read_stocks/ | {
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"Reading stock information is the easy part, analyzing and making investment decisions is the hard part. I'll try to get you started in terms of American stocks. \n\nA stock price is only relative to itself. Priceline's stock is very expensive, $1,100+, but it doesn't mean Priceline is proportionately better as a company than Apple, ~$525. This is why you'll want to look at charts tracking the share price over 1 week, 3 months, or 5 years. You might notice a stock's current price is in a valley on the chart and it could mean that it's a good buy, because it's likely to upswing soon to level out the average price over time. Or will it? The likelihood and severity of upswings and downswings is where real investors make their money.\n\nNumbers such as P/E ratio, Beta, and percentage change can help us read and compare stocks to other stocks by normalizing data into coefficients (such as beta, usually between 0 and 3), or percentages (such as P/E, the dollars you put in to get $1 out). Additionally, we can compare the percentage change of a single stock with its industry (semiconductors, hospitality, etc) or with the market as a whole (down jones, Nasdaq, s & p 500). \n\nTo check out some of the figures you can use to read stocks, look at Bloomberg or Yahoo! Finance. These are easy, beginner-friendly websites or phone apps, full of information. You can check charts to see if a stock is performing well against itself and a plethora of other info I can't begin to summarize here. When you find a ratio or coefficient that you don't know, look at _URL_0_ for definitions and explanations. \n\nTl;dr - Read stock prices against their historic prices, compare percentage changes against other stocks, learn more at Bloomberg, Yahoo! Finance, and _URL_0_",
"This is a long, complex topic. There are substantial books devoted to analysis of stocks and companies. This will be a very gross simplification, and should not be considered investment advice. \n\nStocks are tiny ownership portions, meaning one share represents an equal slice of the total ownership of a business. Because the slice is equal, they become interchangeable and can be easily bought and sold. The first number associated with a share is it's price, this represents the last price at which a trade occurred (there are also current prices to buy and sell additional shares). The price history is what is normally charted by default. \n\nFrom the price, there are two broad schools of thought in how to invest. Both schools feel the other is wrong. \n\nOne school is called technical analysis. This school believes that stocks trade in repeatable patterns and looking at recent patterns may suggest what will happen in the future. The main tool of technical analysis are charting tools, most websites provide a substantial suite of charting tools. \n\nThe other school is called fundamental analysis, this school attempts to understand the underlying business and predict the business' future fortunes. They tend to look at things like financial statements (quarterly reports of the what a business owns, owes to others, how much they earned, and how their cash position changed, as well as details management believes investors will find useful). Ratios tend to be an important way to filter through the huge numbers of companies available to invest. \n\nMost of the other numbers (besides the current price) and charts are provided for those doing either fundamental or technical analysis. "
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5rbxje | what actually causes the pain from being out of breath (like running out of air under water)? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5rbxje/eli5_what_actually_causes_the_pain_from_being_out/ | {
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"CO2 buildup. \n\nSo your blood circulates oxygen throughout your body. Through body processes this oxygen is turned into carbon dioxide (CO2). Your blood takes this back to the lungs and you breathe it out. CO2 is not a good thing to have in your lungs, so you want to breathe it out. When you don't do this your brain gets upset. It starts yelling at your lungs to let out the CO2, and it does this by causing pain. Pain is your body's way of trying to stop whatever damage is happening to your body. The more CO2 builds up in your lungs, and the less oxygen you have circulating, the more the pain increases as your body essentially starts to panic. "
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716icg | sleep deprivation - if you have a sleepless night and then proceed to get the recommended 7.5 hours of sleep the following days, for how long will you be in a sleep deprivation? | To Clarify: I want to know if the body evens sleep deprivation or "catches up" over time, even if you do not compensate with extra sleep. For instance, if I have a night where I only get 4 hours of sleep, I would try to get 9 hours of sleep the following night to "catch up". However if I only get the recommended sleep around approximately 7.5 hours the following night, will I then still be in a sleep loss? If so, how many nights consisting of a "normal" amount of sleep will I need to regulate one bad night?
Edit: thanks for all your interesting responses! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/716icg/eli5_sleep_deprivation_if_you_have_a_sleepless/ | {
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"We just talked about this in my psychology class today. There's a case study about this guy who, as a high school student, wanted to break the record of longest number of days without sleep (which was 11 days at the time). He made it 12 days, probably with some \"micro sleeps\" here and there. He suffered all kinds of side effects, from headaches to irritability to hallucinations and more. When he finished, he slept about 12 hours a night for three or four nights and was right back to normal with no lasting effects and was able to go back to a regular sleep schedule. So really the idea of your body having to catch up isn't completely accurate. Your body just needs sleep in general to function properly and consolidate memories/repair itself. If you have one sleepless night you'll probably have a rough day, but if you get the recommended amount of sleep the following night you should be right back on track. ",
"Long time ago (more than 5 years ago) I read in a science magazine about this subject. \n\nIf you go a night without sleep, you should continue your regular sleep pattern the following nights, it only takes a few nights of sleep to \"catch up\" no matter how much sleep you have missed on the first night. What is important is to keep the same sleep pattern all weekdays, because it is more healthy for the body. So young man, this is why you are not allowed to stay up late in the weekends. Now go back to bed.\n\nI read this long ago, so I cannot come with an actual source and cannot guarantee if the research is up to date.",
"How do you know how many hours of sleep are good for you if everyones body is different?\n\nAlso how do you know if the amount of hours you slept is good for you or it was just luck that you woke up at the end of a sleep cycle?",
"_URL_1_\n_URL_0_\n\nWe sleep to remove the waste products our neurons create while they function. During sleep, the neurons narrow, and the glymphatic pathways expands, allowing significantly more passive flow of the cerebrospinal fluid (CSF) that carries the waste products out of the brain. \n\nThe longer we go without sleep, the higher the concentration of the waste products in the fluid. This would also mean that proportionately more waste product is removed from the brain if you have gone longer without sleeping--in the same number of hours of sleep.\n\nFollowing this line of thought, when you are 'catching up on sleep' you do not need to make up hours additively. The first few hours of sleep are proportionately the best. This makes sense with the anecdotes you read in the other comments.\n\nSource: Interest with sleep stuff & medical background & did some neuro research in medical school-but I'm also not a neuroanatomist. The first 1.5 paragraphs is based on recent research, the last bit is biologically-plausible theorizing based on this brand-new research behind the glymphatic system, which provides a basis for why we need sleep at all. "
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60yilv | why do some cars have one exhaust pipe and others have two of them? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/60yilv/eli5_why_do_some_cars_have_one_exhaust_pipe_and/ | {
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"An exhaust system's function is to move exhaust gas from an engine's combustion away from the engine. Larger/more powerful engines need to move more air than smaller ones. This can be done 2 ways: a bigger pipe, or more pipes. Deciding which to use is pretty much entirely up to the car designer/manufacturer.\n\nSo basically, it boils down to: because somebody arbitrarily made it that way.",
"Just as a little refresher, [a standard 4-stroke engine has 4 phases](_URL_0_):\n\n1. *Intake* - piston goes down drawing air + fuel into the cylinder\n2. *Compression* - piston goes up compressing air+fuel mix\n3. *Power* - **EXPLOSION** drives piston down creating force\n4. *Exhaust* - piston goes up pushing burnt fuel out of cylinder\n\nEverything but the power phase is \"wasting\" energy.\n\nThe exhaust and mufflers on a car are there to cut down on the noise of all these explosions going on in the engine. Unfortunately, they create some back-pressure in the system making exhausting slightly harder and robbing the engine of power. A dual exhaust gives you two separate exhaust lines so that there's slightly less pressure, resulting in more power.\n\nDownside to dual exhaust is that they're more expensive. Most cars use singles because it's cheaper.",
"It's an arbitrary decision by the car designer.\n\nIt is true that the exhaust system creates some back pressure, and that thicker or more pipes would reduce this pressure, but if you look at the pipes under most cars, you'll see one pipe go from the engine through the catalytic converter towards the rear, at which point the single pipe splits into two pipes of the same thickness. Rather pointless, as far as pressures and exhaust gas movement.\n\nThe decision is determined by aesthetics. We find things that are symmetrical a bit more pleasing than things that are not. Exhaust pipes on both sides of the back of the car = symmetry.",
"The bigger and more powerful the engine, the more exhaust it makes. You'll normally see single exhausts on 4 cylinders and below, while you'll see double exhausts on 6 cylinders and up.\n\nExhaust pipes that are too long, narrow or complex cause back pressure which robs power from the engine. \n\nSometimes cars that are supposed to look sporty have an exhaust that splits into two when they don't really need it, which is funny because it actually reduces performance.\n\nEdit: Keep in mind that very few decisions in auto design are \"arbitrary\". Companies that build millions of cars can't afford to lose a couple dollars a vehicle because they didn't do the research. \n\nAlso, improving performance doesn't mean going faster, it really means increasing the efficiency.",
"If not purely for aesthetics, then it's because of cylinder configuration. \nInline engines will have one bank of exhaust headers, a v-shaped will have two. ",
"I have an anecdote. My 2009 Subaru Forester has a dual exhaust for the purpose of cutting down on emissions. \nIt employs a \"Partial Zero Emission Vehicle\" system, which uses two large catalytic converters. Interestingly enough, the added precious metals add about $500 to the value of the vehicle. ",
"An engine is, very basically, a big gas pump in which explosions happen. The exhaust's job is to let gas flow out of the engine. As the volume of gas goes up (with engine size, performance, or revs) you need to move more gas.\n\nUp to a point, making the pipe bigger is the easiest way to do that (a circle is the most efficient shape in terms of cross-section Vs material use) but eventually it would be too hard to bend a big fat pipe to fit under the car (bigger pipe means wider bends) and you'd have to make a big hump up the middle of the floor to accommodate a big fat (and red-hot) pipe. Two smaller pipes can be bent more sharply, laid \"flat\" next to each other or routed through smaller available spaces individually.\n\nOne benefit of smaller pipes is they keep the speed of the gas flow up, which can be helpful and even act to \"suck\" gas out of the engine due to the momentum of the flow. There's whole books written on exhaust design & tuning, very few people really understand it but most assume bigger = better, despite what manufacturers do after spending billions on R & D.\n"
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bd2cas | why do drivers turn the radio volume down when they are lost? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bd2cas/eli5_why_do_drivers_turn_the_radio_volume_down/ | {
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"One less thing for their senses to take in, enabling them to better concentrate on where they are/how to get on track.",
"To minimize distractions. For many people, a loud noise (even familiar noises like music) interfere with their ability focus. This is not necessarily the case for repetitive tasks like studying or memorization where having music can often help, but when figuring something out for the first time (like how to get from where you are to where you want to be), noise and other sensory inputs can be disrupting and cause people to lose focus.",
"Being lost requires more concentration and more focus than normal driving. Turning down the radio allows for the brain to eliminate the task of trying to audibly process the music, and instead focuses more on visual processing (to help find the correct route)."
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evvcao | why is it so hard in 2020 to print special characters (é, œ, à, û, etc.)? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/evvcao/eli5_why_is_it_so_hard_in_2020_to_print_special/ | {
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"Newer devices all now understand Unicode, the universal character set that can encode virtually all of the world's languages. However, printers, especially commercial/industrial models, are often in service for years or decades. Older models may not have support for Unicode-encoded text at all, meaning they treat it as some other character set, leading to \"mojibake\" (random-seeming garbage text). Even if they do support Unicode, the built-in fonts will not have a \"glyph\" (shape) for every single Unicode character, as there are more than 100,000 assigned characters, most of which are rarely used, and more are assigned in every new Unicode version. If a printer receives a character it doesn't have a glyph for, it may substitute a replacement character.\n\nSource: I used to do I.T. in a warehouse where we had somewhere around 100 industrial label printers of varying age and capability.",
"Technology has solved this problem a long time ago. Those keys are easily available using ASCII, and on mobile by holding the character you need. However, many of the people making labels and things aren't actually that interested in their jobs AND have no supervision, so they let the software go nuts and confuse itself, or take a \"shortcut\" compared to typing the right thing."
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1jtj3w | why is internet content from russia notoriously crazy? | Why do a hell of a lot of crazy videos come out of russia, and why is the Russian side of the internet known for being sketchy and whatnot? Essentially, why is the Russian internet culture so much more eccentric and drastically different from other western nations? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jtj3w/why_is_internet_content_from_russia_notoriously/ | {
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"I suspect the material that makes the rounds in the West gets selected that way. I live in Finland, a neighboring country that once was a part of the Russian Empire, a place where you can take a (relatively) high-speed train to St. Petersburg, and Finns still know next to nothing about Russian popular culture or politics. I couldn't name a Russian singer or actor without googling for one (well, maybe Anna Netrebko). I suspect the US public at large knows even less, if at all possible. So, the videos that make the rounds are not Russian Idol or such, but car crashes and drunk people trying to dive into frozen lakes, which work without context.\n\nThat said, traffic generally really is bad in Russia, and nowadays everyone there seems to use a dashboard video camera as an insurance policy, so we get a lot of video of accidents."
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5shpk4 | the bowling green massacre | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5shpk4/eli5_the_bowling_green_massacre/ | {
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"\"The Bowling Green massacre is a nonexistent incident referred to by U.S. Counselor to the President Kellyanne Conway in an interview on the television news program Hardball with Chris Matthews on February 2, 2017. Conway cited the \"massacre\" as justification for a travel and immigration ban from seven Muslim-majority countries enacted by United States President Donald Trump. However, no such massacre ever occurred. The next day she said she had misspoken and had actually been talking about the 2011 arrest of two Iraqi refugees in Bowling Green, Kentucky, on terrorism charges.\"",
"Kellyanne Conway is a counselor to the president, who recently in a speech mentioned an event called the bowling green massacre as evidence for the need for more strict immigration rules.\n\nHowever, there was no such massacre. What *actually* happened is that in Bowling Green, Kentucky, an FBI agent posing as an Al Qaeda member approached two Iraqi refugees, asking if the two wanted to help him obtain and ship weapons to the extremists back in Iraq. The two men agreed, and obtained weapons illegally, at which point the FBI revealed itself. The two were arrested and the incident prompted a six-month rescreening of all incoming Iraqi refugees. However, it's important to note that at no point was there even a plan or effort to attack US citizens with the weapons, just ship them.\n\nUpon further digging, it's become apparent that Kellyanne Conway has on two other ocassions also referred to this nonexistent massacre, causing people to suspect it was no slip of the tongue but an intentional false presentation of events in order to generate support for President Trump's immigration ban. This is also the same woman who gave us the \"altnerative facts\" quip, so a lot of the media already considered her a joke. ",
"It was just a simple sting operation that ended simply. Overall it was a Bowling Green kerfuffle.",
"Never happened. Kellyanne Conway, in her zeal to defend the travel ban and \"Muslim ban\", said that legislation like this was necessary to prevent another \"Bowling Green Massacre\". She's since tried to walk back this claim, stating that she misspoke and meant to say \"terrorists\"... but it's highly unlikely it was unintentional or just a mere slip of the tongue when you consider this is the same woman who brought us \"alternate facts\". She's also made this same claim on at least 2 other occasions, and the word terrorists wouldn't have fit the context of the sentence she was using at the time in this instance. (As far back as 2011, she said in an interview about Obama: “He did that because two Iraqi nationals came to this country, joined ISIS, traveled back to the Middle East to get trained and refine their terrorism skills and come back here, and were the masterminds behind the Bowling Green massacre of taking innocent soldiers' lives away.” She's also made similar statements on at least 2 other occasions, and has referred more than once to \"innocent soldiers\" in Bowling Green, KY being killed by terrorists.) \n\nWhat actually happened was that two potential terrorists (mind you, they had not yet committed any acts of terror on US soil, but they did claim responsibility for attacks on US soldiers in Iraq and were attempting to send money and weapons to Iraq for what we can only presume are the same purposes (attacking US soldiers in Iraq). However, that does not serve to bolster her argument because the ban was purportedly intended to prevent *domestic* terrorism...so she offered an \"alternate facts\" version. Which is to say, she lied."
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370d43 | why can't children gamble on slot machines/online? but they can use coin pushers? | Never made sense to me. OK, with coin pushers you're only gambling tiny amounts of money at a time but when I was a child I could easily spend £10 in an hour on them. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/370d43/eli5_why_cant_children_gamble_on_slot/ | {
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"I suppose it's because the coin pushers could be seen as a game of skill, whereas slot machines are just down to luck."
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ex0zl0 | how much cash in the world is actually just digital? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ex0zl0/eli5_how_much_cash_in_the_world_is_actually_just/ | {
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"There's not nearly enough. Less than 10% of money is physical cash. Most is just numbers on a computer."
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4kqhdz | an 8 year old can magically recreate a complex jazz piece on the piano without any formal training in music. how does natural talent work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4kqhdz/eli5_an_8_year_old_can_magically_recreate_a/ | {
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"For a specific response please give an actual example, as there are a few different things that could be going on.\n\nFor example, already I want to ask you \"so they didn't get formal training, but what ***informal*** training did they receive? If a kid spends time training to play the piano, it doesn't need to be \"formal\" training for them to get good at the piano.\n\nThere is no natural talent that will let you walk up to an instrument for the first time and without having any prior experience be able to play it well. But there are plenty of social or biological situations in which someone might be expected to learn faster than you'd expect another kid to learn.",
"There is a lot of scientific evidence that there is really isn't such a thing as \"natural talent\", but rather it's a product of childhood development on a particular skill set with a specific form of practice.\n\nAnders Ericsson recently published a book that spans his professional career on this topic called \"Peak\". He also recently appeared on the [Freakonomics Podcast](_URL_0_).\n\nSo to answer your question: there's probably a lot more to the story than has been revealed.",
"I have perfect pitch. \n\nI really dislike that term because it implies that I am somehow \"better\" than other musicians. This is not the case. I can simply hear a note or chord and tell you what the note is or all the notes within said chord. \n\nI caught lots of glares and harsh words from my fellow students while in music school (education) and thus I rarely revealed my \"talent\" after my first semester. \n\nThe way I rationalized it was that there are TONS of musicians who work very hard on ear training and still can't discern notes or the notes inside chords without a reference pitch. They seem to resent those who can do it effortlessly. \n\nI can actually sing notes on command. I can also detect variances in pitch to within 3-5 cents. When my professors discovered this they would often exclude me from answering listening-based questions in class. One of my theory instructors went as far as to alter the pitch of certain passages during our listening exams. This made me laugh because not only could I detect it, but I could mentally transpose the passage with no issue. It literally infuriated her to the point that she decided to give me a separate exam with no listening involved because she said it \"isn't fair to the other students\". \n\nSo I'm normally pretty guarded about it. Sorry if this seems like a fedora tip - just offering a bit of insight. \n\nEDIT: left some stuff out "
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mlyic | why do i get head rushes? | To clarify: my definition of a 'head rush' is dizziness and "seeing fuzz" upon standing up, with me, sometimes to the point of falling over. What causes this and what's the science behind it?
Is it sinus related?
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/mlyic/eli5_why_do_i_get_head_rushes/ | {
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"when you stand up fast, the blood in your head slides down into your body. it takes a minute for your blood to pump back up into your head. ",
"When transformers transform, they probably get some kind of a rush. Our bodies do many very amazing things all the time and we are not aware of them (Balance, breathing, etc.). What we might not think of as significant (Standing up after laying down, etc.), can actually be quite a big deal, in the same way a transformer doesn't think very much about changing from a car into a robot.",
"This is called orthostatic hypotension",
"when you stand up fast, the blood in your head slides down into your body. it takes a minute for your blood to pump back up into your head. ",
"When transformers transform, they probably get some kind of a rush. Our bodies do many very amazing things all the time and we are not aware of them (Balance, breathing, etc.). What we might not think of as significant (Standing up after laying down, etc.), can actually be quite a big deal, in the same way a transformer doesn't think very much about changing from a car into a robot.",
"This is called orthostatic hypotension"
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7wxzlf | what is the difference between ice dance and pairs skating? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7wxzlf/eli5_what_is_the_difference_between_ice_dance_and/ | {
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"Pairs include lifts above the shoulders, throw jumps and side by side spins. \n\nDance includes a set dance pattern for short dance (everyone does the same thing for part of their routine), lifts only to the shoulder, a turn (twizzle) sequence and like its name is more of a ‘dance’ \n"
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1yxtax | why do pizza places charge a delivery fee and not give any of it to drivers? | I just ordered some pizza and noticed a $3 "delivery fee" with a note that it doesn't go to the driver. What gives? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1yxtax/eli5_why_do_pizza_places_charge_a_delivery_fee/ | {
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"The note is there to instruct you that the fee is not a tip, and you should still tip your driver. The delivery fee is to make a couple extra bucks on each delivery for profit and to account for the real cost of doing business that delivering a pizza takes. "
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3wdyhb | why are pickup trucks, even ones with more than 100k miles, so expensive? | I understand there is a demand because contractors need them to run their businesses, but is that all? I'm in the market for a truck and a new, mid-sized, 4wd pickup is $30K minimum. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3wdyhb/eli5_why_are_pickup_trucks_even_ones_with_more/ | {
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"I'd assume it's also the construction of the truck. Larger everything makes it cost more to build. ",
"Because of the 4x4 option, look at 2x4 trucks of the same make and the price drops considerably. \nIf your not opposed to buying used you can pick up a used fleet truck 150-200k miles for 5-7k at auction. ",
"Trucks have much more utility than a mini Cooper, generally speaking. The mini gets great mpg but a truck can tow, go off road, transport large items, etc. Their utility keeps them pricey. If you can scrounge together the $$$ it's worth it to get a new one. You can usually talk salesmen down a good bit.",
"Pickups are used heavily by small businesses, small businesses don't tend to upgrade until they have to - in this case \"until they have to\" usually means \"until it's not economical to repair the truck\"\n\nUnlike with a family car, which you may change every 2-5 years, a company will generally buy a pickup either new or nearly new, then just run it until it doesn't go any more... it's only being used to haul stuff around, there's no upgrade requirement: it either runs or doesn't, and by the time it doesn't it's usually scrap.\n\nThis means there aren't many running high mileage trucks up for sale. Combine this with good demand for used trucks (because they're useful enough that at $3000, everyone would just get one) and the price goes up.\n\nIn short: lots of people want a truck, and nobody sells theirs once they have it. Low supply and high demand pushes prices up.",
"Profit margins are relatively high on trucks because they sell like a luxury product, which makes them more expensive.\n\n\"Ford’s profit margins are approaching or surpassing those of German luxury automakers such as Daimler AG (Mercedes) and BMW AG\"\n\n_URL_0_\n",
"No one has mentioned the [chicken tax](_URL_0_) yet.\n\nIn 1963, in response to tariffs which France and West Germany placed on the import of US chicken, the US placed a tariff of 25% on all light truck imports. This tariff is still in place today.\n\nBecause of this, domestic producers of trucks (or trucks produced in Mexico and Canada) can charge significantly more than they would normally be able to, due to reduced competition.\n\nFrom wikipedia: \n\n > Robert Z. Lawrence, professor of International Trade and Investment at Harvard University, contends the chicken tax crippled the U.S. automobile industry by insulating it from real competition in light trucks for 40 years",
"Something I don't see anyone mentioning is the \"Cash for Clunkers\" program passed in 2009. It gave significant cash discounts for people to replace vehicles with under 18 MPG efficiency with vehicles that had 22 MPG or better fuel efficiency. All vehicles traded in under the program had to have their engines destroyed. The purpose of the program was twofold. One, it was supposed to replace older inefficient vehicles on the roads. Two it was supposed to provide an economic stimulus.\n\nHowever one of the unintended side effects was that it permanently reduced the inventory in used truck market. Roughly 665,000 vehicles were traded in and destroyed; these consisted largely of SUVs (most notably the Ford Explorer) and trucks (especially Ford F-150s a Chevy C 1500s). Prior to this trucks weren't keeping their value especially well. After this the prices for used trucks skyrocketed. I ended up looking for a used truck in 2010 and found that most makes and models were retaining up to 80% of their new value for up to five years. The market for used trucks has gotten quite a bit better then that in the last five years. But it'll probably be another decade before used stocks catch up to their 2009 levels. "
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3y9knw | what makes makes a swear word so offensive? what is offensive, for example, about the word "fuck"? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3y9knw/eli5_what_makes_makes_a_swear_word_so_offensive/ | {
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"From what I know, it seems to be a bunch of arbitrary elitist horse shit that dates back a few centuries. Consider the word \"vulgar\". Aside from its modern meaning, its original meaning was along the lines of \"common\", as in \"commoner\". \"Vulgarity\" was the way common people spoke, and as such, it became offensive in polite society. The polite word was typically the Latin, ex. \"feces\" as opposed to \"shit\".",
"Most swear words involve something distasteful or personal. Hell and damnation aren't topics that one should take lightly if one assumes they are real things. Shit and assholes are gross, and fucking is a very personal activity. I think we as a society have simply decided that these are topics that should be shown respect or decorum when they are discussed.",
"Four letter swear words are all derived from the old English that commoners in England spoke in the Middle Ages. When the French invaded England and became the ruling class in the 11th century, suddenly a lot of old English words were deemed vulgar. That's why \"shit, piss, and fuck\" are vulgar swear words, while their French/Latin derived counterparts \"defecate, urinate and fornicate\" are considered more polite. "
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6uhibw | what happens to building under construction during an earthquake? are there precautions taken to mitigate damage? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6uhibw/eli5_what_happens_to_building_under_construction/ | {
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"The only precautions that you can take are the one you are building into the building itself. Unless it is close to being finished odds are that there are no precautions that can be taken. \n\nEarthquakes are not common enough for construction precautions to be developed either. ",
"Most of the measures taken to make a building resistant to earthquakes are installed in the early part of construction(tie-downs, shear paneling ect...). It's not really to mitigate damage during construction, as much as it's the easiest order to build, but it does mitigate the risk quite a bit. "
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1tns81 | how are cryptographic hashes like md5, sha one way? | I'm a self learnt web developer but one thing that's always bothered me is that the (some) hashing algorithms are one way, that is you can't decrypt the original from the hashes. From what I understand encrypting/hashing is just a set of mathematical algorithms, so why can't we go backwards in some cases and obtain the original text? It can't be due to randomness since we obtain the same hash for the same given text. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1tns81/eli5_how_are_cryptographic_hashes_like_md5_sha/ | {
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"Here's a very simple one-way hash: count the number of letters in a word.\n\nbob = 3\n\napple = 5\n\norange = 6\n\nYou always get the same hash from the same word, but you can't possibly guess what word I used if I just say '7'.\n\nOne-way hashes lose too much of the information to get back to the original text. Remember, a hash is not a cipher or an encryption.",
"The reason is that hashes like MD5 and SHA **are used not to compress digital data, but to validate the integrity of such**. Call it files or passwords, let's say passwords:\n\nWhen checking the integrity of a password in a website, it is not necessary to know the password in order to verify that it is being submitted correctly by the user. The only thing needed is to validate a correspondence between the stored hash key (the one generated when the guy signed up) and the generated hash key obtained from the user input at each login time.\n\nThis may sound oversimplified, but let's say you have two input numbers: 4 and 6. Lets use a hypothetical algorithm that is simply an addition. Our output will be 10. So let's say there's a guy who needs to input these numbers correctly in order to generate the appropriate output (hash key). In this hypothetical case, as you may notice, there is a hysterical probability of collisions: the inputs may be 1 and 9, 8 and 2, even 6 and 4 and so forth, and we'd still be getting a 10 in the output. Except in the cases where the two input numbers don't add to 10 (5 and 7, et c.).\n\nBUT! Hash algorithms are supposed to be **complex enough** (hell, they are **way** more complex than a simple addition) to avoid collisions (two different inputs generating the same hash key).\n\nMy point is, the website only needs to verify the **10**, to make sure the guy is writing down 4 and 6. It doesn't need to know that the guy inputs a 4 and a 6.\n\nI hope I didn't make it more confuse lol. Cheers.",
"Hashing can be one-way in two different manners.\n\nOne is that the set of inputs can be larger than the set of outputs. Given an output there can be multiple different inputs and it's literally impossible to know which. This is what /u/pobody explained. But this is actually not a very interesting property.\n\nThe interesting thing is that they can be \"computationally\" one way. That is, given the output it would take you a very, very long time to find the corresponding input. An example of this is prime factorization. It's easy to multiply two large primes, but it's hard to find the prime factors of large numbers"
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ecggvt | why are we still dependent on plants for drug components, why can't we just see the composition and artificially make those ourselves? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ecggvt/eli5_why_are_we_still_dependent_on_plants_for/ | {
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"Why would we if a plant do it for us, cheaper and automatically?",
"Letting a plant do it is usually much cheaper and easier than constructing a petrochemical plant to manufacture it.\n\nIn theory you can industrially fabricate almost any organic chemical from crude oil raw inputs, but in practice it's fabulously expensive and monstrously inefficient.\n\nIf a plant has already evolved a way to assemble it for you, you either grow the plant or try and clone that gene sequence into bacteria or yeast so they'll do it in a vat. Synthetic production is a last resort.",
"Basically it's ridiculously hard to make something, compared to just taking it out of something else.",
"That’s a bit like saying, why do we depend on stores to get cookies, why can’t we mill the flour, harvest cacao beans, cut down sugar cane stalks, and harvest vanilla bean pods.\n\nBecause it’s a difficult, long and arduous not to mention expensive process to go through for fucking cookies."
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3z0544 | how does the spin of an electron cause magnetism? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3z0544/eli5_how_does_the_spin_of_an_electron_cause/ | {
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"Electric fields and magnetic fields both operate by the same fundamental interaction - electromagnetism.\n\nThis means that electric fields can cause magnetic fields, and magnetic fields can cause electric fields.\n\nThis is because they're both expressions of the same fundamental thing - electric fields and magnetic fields are essentially the same field, it just depends upon the way in which you observe them that determines what you see.\n\nThis means that you can have two people in different reference frames looking at the same field, and one will see a magnetic field while the other sees an electric field.\n\nYou can kind of think of it like movement in 3-dimensions: you can move in the x, y and z direction.\n\nIf everyone defines \"x\", \"y\" and \"z\" relative to themselves, so that x moves left to right, y moves forward and backward, and z moves up and down.\n\nIf you then take a ball rolling in a circle and have 3 different people looking at it, one person could see the object moving backwards and forwards from left to right - the object's moving in the x-plane for them.\n\nAnother person looking at it if they're rotated could see the same object moving up and down - the object's moving in the z-plane for them.\n\nA third person looking down from the top could see the object moving both left and right and up and down - in the x and z planes.\n\nYou can even get fancy and have people looking at it from in-between angles, so that they see an apparent ellipsoid - the object is moving more in one plane compared to another from their perspective.\n\nIf you then think about magnetic and electric fields rather than movement - depending on how you look at it you could be seeing either magnetic, electric, or some combination of the two.\n\nSo spinning electrons produce an electric field as they're moving current - this electric field is *also* a magnetic field when looked at from the right frame of reference."
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3wm9gy | who determines the speed in curves when people first make the roads? | Is there just math or do the determine to road prior? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3wm9gy/eli5_who_determines_the_speed_in_curves_when/ | {
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"Speed limits on roads are determined mostly by sight lines, how quickly you can react to an obstruction and stop safely. The math is well known, and for most practical road shapes the safe speed limit has already been calculated and can be looked up in a book. These calculations have over time been tested and verified by standards organisations like ASTM and SAE. In special cases an engineer may do a calculation to confirm what the speed limit should be if for some reason the road shape they want to use is not already tabulated, although this is rare as engineers would prefer to use a standard design to avoid the risk of something new.",
" The drivers, mostly.\n\nA lot of people don't realize that speed limits in most areas are determined by checking the speed of cars on a roadway or curve and using the speed that approx 85% of drivers use.\n\nThe theory is that 85% of drivers are going to go the speed roadway conditions allow. If the speed limit is too low for conditions many people will ignore the speed limit.\n\nNaturally, there are exceptions. Like when the city council or someone thinks they know better than the traffic engineers.\n\nSource - I did traffic control studies for several years, including speed studies, for the purpose of determining speed limits.\n\nAnother source - _URL_0_",
"This depends on what state/country you live in. I reside in Missouri/USA and here they are determined mathematically based on the max weight and size of vehicles allowed to travel on the road. The heaviest/largest vehicles will usually be 10-15 miles/hr slower than the average consumer vehicle.\n\nSource: My dad was one of the guys that did this and I helped him when I was learning calculus as a practical example.\n"
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41kvhe | why would somebody sue the gun manufacturer after a mass shooting? | Unless the gun manufacturer sold the weapons to a known criminal how in anyway are they liable for what some crazy would do? You wouldn't sue Budwieser or ford if a drunk driver hit you. So why would you sue the manufacturer of a gun if some crazy used it? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/41kvhe/eli5_why_would_somebody_sue_the_gun_manufacturer/ | {
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"The victims family's of mass shootings want someone to pay. They see gun manufactures in being complicit in these shootings. I'm sure some has to do with the fact that in all the parties involved they're the ones that have money to go after. \n\nEdit:\n\nAlso, Protection of Lawful Commerce in Arms Act prevents in most cases legal action against manufactures and dealers. So, even though they want to most can't.",
"It's one of the stupidest ideas ever. Hillary and whoever else wants this to happen should eat a pile of cold turds",
"Sometime the bars the driver was at before driving drunk do get sued for drunk drivers though. I think the \"drink responsibly\" clips at the end of beer commercial might be a preemptive disclaimer. \n\nPerhaps suing the gun manufacturer won't create a win, but might make the manufacturers think about who they distributed to.",
"You have the right of it with your mindset. Unfortunately, in the 1990s and early 2000's, anti-gun groups filed tons of law suits against the gun manufacturers and retailers on behalf of gun violence victims, with the express purpose to try and bankrupt the manufacturers and retailers.\n\nEven knowing they wouldn't win the suits, they kept piling them up, one after another, after another, to make the manufacturers and retailers lose money paying for lawyers, expert testimony, investigative staff, and the like.\n\nThat is the reason the Gun Manufacturer and Retailer law went into place, to block these frivolous law suits. The lawsuits bankrupted small retailers, and made the potential cost of entering the gun manufacturing business too high to be worth it unless you were already a huge company.\n\nMany people on here are trying to justify it, by saying things like \"it will make them act more responsibly\" and so on, but the truth is, the manufacturers are already acting responsibly. They do not sell to individuals in almost all cases, only to retailers, who are licensed dealers or wholesellers. They make their items to meet all standards and regulations. If they don't meet standards and regulations, they can be sued for negligence, as any other business can.\n\nRetailers are where it gets a little more dicey. People want to be able to blame them for selling a person a gun if that gun is later used in a crime. The issue is, if the retailer did everything by the book, did the background check, and so on, then they legally shouldn't be held responsible. If they didn't do their jobs, then the law shielding them from a lawsuit doesn't protect them, and they can be taken down by the ATF for failure to follow the law.",
"In some certain cases some weapons were found (not sure if legally) to be designed specifically for killing people in an urban setting, and being sold exclusively for civilian use. Nothing about those weapons make sense for hunting, sport shooting or reasonable self defense (spray and pray is not a self defense tactic) etc. I think the tec9 was a good example of this. Too inaccurate for any kind of aiming but perfect for up close spraying. While the manufacturer has been found not liable many states still ban it specifically.\n\nIn most other cases there are other uses for guns sold on the civilian market such as hunting, target shooting, or self defense. Even if a gun seems optimized for killing humans."
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32qqcp | how does selective breeding work? | I know we choose to breed the animals with traits we like,but do we just wait for mutations in the dna to happen and are they really that visible that we can tell exactly which animal to choose,can we only do it in with some species.I mean why not make glow in the dark jelly fish just because or non-venomous snakes for example to have as safe pets. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/32qqcp/eli5how_does_selective_breeding_work/ | {
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"We can selectively breed any species that mates. We have made glow in the dark jelly fish and non-venomous snakes using genetic technology, but a lot of people forget that selective breeding began with the dawn of our civilization. We've selectively bred Chickens, Cows, Pigs, Corn, Bananas--everything we eat was selected to be tastier or easier to grow and maintain for humanity. Regarding traits, we cannot create traits from DNA that doesn't exist, but we can see every single trait within a species using our current genetic methods. With that, we can choose which animals mate.\n\nIf you want an example, we can look at dogs. It probably began where two relatively less aggressive dogs (we'll give them rating 8/10) were mated. Maybe the couple gave birth to a dog who is 7/10 aggressive who mated with a 9/10. Over time, we choose mates who would maybe get us down to a 5/10 aggressive dog. This is why it's said that it takes a very long time to domesticate an animal, or sometimes it's impossible due to how central aggressiveness may be to the animal's reproductive success.",
"They're that visible. We choose which traits we like and then we breed that trait over and over and over in hopes that it will strengthen in the trait in the subsequent generations.\n\nFor your examples, first we would need to find glow in the dark jelly fish and reproduce those individuals. Then reproduce the offspring and so on and so forth. Assuming that the subsequent generations retain that physical trait, it will increase the genetic frequency of the trait (i.e. how often it appears in a population).\n\nTo breed a non-venomous snake, you would need individuals that are non-venomous to start with. Say there are two king cobras, one male and one female, with a mutation that does not allow them to produce venom. It is feasible to say that mating those snakes, and then those snakes' offspring, will yield a population of non-venomous king cobras.\n\nSo yeah, you would need the mutation to arise first. Or you could introduce the genetic information into the organism (as we do in genetically engineered things)."
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cr23vq | why do our sinuses go into production overdrive when we get a head cold? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cr23vq/eli5_why_do_our_sinuses_go_into_production/ | {
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"Mucus (booger, snot) traps viruses, bacteria etc. inside it, and by coughing and sneezing you remove those pathogens from your system. It also helps keep your mucous membranes moist, since fever and sneezing tends to dry them out."
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ftdnf1 | what is habeas corpus? | Layman’s terms. Examples, if you can too, please! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ftdnf1/eli5_what_is_habeas_corpus/ | {
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"Basically it is a legal requirement for there to be a legitimate reason for someone to be arrested and detained, the court checks that the reason for detaining the person is legitimate and there wasn't anything wrong with the arrest.",
"It literally translates to \"may you have the body\". Essentially what it means is that without a body(evidence) there is no proof a crime was committed. What this translates to in modern court is that a person cannot be brought up on trial for a charge without evidence that a crime was committed. In short habeas corpus is the requirement to prove a crime has occured. \n\nExample, you can't just be charged with speeding because an officer thinks you were speeding, but if they have video or photo evidence of your car speeding then charges could be brought. Still have to prove you were driving though.",
"It means that there is a requirement to produce the accused to a formal court and have the charges presented to them. \nIt is to ensure that the accused has the opportunity to face their accusers and that this process is transparent.",
"I means you need proof that a bad thing was done before you punish the person who did the bad thing.",
"'Habeas corpus' is the Latin legal maxim that translates to 'you have the body' / 'produce the body'. \n\nThe other answers correctly state that it is to affirm that there was good reason for an arrest that was made.\n\nMost countires require that the arrested person be brought before an authority, be it a court or a magistrate or a state attorney, within a certain period of time after arrest, to be charged for what they have been arrested for. It exists for the simple reason of avoiding delaying the judicial process, and more importantly, *ensuring that no innocent man remains in custody for long in case of a wrongful arrest.*\n\nHence, it is a ***summons with a court order behind it.***\n\nEdit: the summons is made to the custodian of the 'body' in question.",
"Other people have done a good job saying what it is, it's also useful to imagine the opposite. Without habeas corpus, or a similar legal concept in countries with different legal history, the following scenarios may happen.\n\n* The government arrests you and never shows your face again. Maybe you are dead, maybe you are in a work camp, maybe you are in a jail cell. Nobody knows, and nobody has the right to ask.\n* Arrest you, give you a day in court, but never accuse you of specific crimes or present evidence. They just say \"Nixstar committed crimes against the state, and we think they are guilty\" and then throw you in prison.\n\nThe above things often happen in dictatorships or corrupted governments, but in a properly functioning government you as the arrested person, your lawyer, or even perhaps a friend or family member can start a process demanding to see you in court. If the judge, police, or other government body can't or won't bring you in, then they can be charged with a crime themselves.\n\nFinally, if the government can't accuse you of a specific crime and show at least SOME evidence for your arrest, then you can demand to be let go. They can still investigate you after letting you go, but they shouldn't continue to hold you.",
"Latin for, \"produce the body.\" Fancypants for, \"Why the heck am I here?\" It's an emergency (high priority) procedure in which you ask a judge to get someone in front of the court, along with a government representative. You then ask the government representative, \"Why have you arrested / detained this person?\" The judge then decides if that person still needs to be detained. Instead of waiting forever to get a court date, HC matters are typically moved to the front of the line.",
"Nobodies mentioned this either so I’ll chip in an extra tidbit; this actually dates back to the Magna Carta so is legitimately one of the oldest legal concepts still in circulation. Its part of the ‘common law’ so spread to the entire commonwealth/ex-commonwealth very early on in the development of their legal systems. I couldnt speak to the UK or US specifically but its not specifically enshrined in legislation or an act of parliament; its simply one of those legal principles upon which legal thinking is bullt. It does, however carry legal weight when there is an absence of any other specific laws that take precedence.",
"Way back, kings could throw people in jail or have their heads cut off for no reason, or on trumped up charges, without a trail, and often without even telling the victim why they were in jail. Magna Carta introduced ‘habeus corpus’ to stop this. It means ‘show the body’, which is meant to mean ‘produce the evidence’. This curtailed the random abuse of power, and began a system where everyone received equal treatment, and had the right to know what the charges against them were, and who their accusers were."
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3b3bz3 | why can't you upgrade hardware on consoles such as ps4? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3b3bz3/eli5_why_cant_you_upgrade_hardware_on_consoles/ | {
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"because then it just becomes a PC. One of the main advantages consoles have is that they are all the same. It makes it very easy for developers to make a game because they know exactly what hardware you have.",
"That's undesirable. The machines are all the same from the beginning of production to the last unit, so all games for that platform can target the same configuration, the gamer's experience will be uniform across the whole platform."
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1jid0b | what is a database? and what is sql language used for? why are some comercial databases(oracle) really expensive and some are free? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jid0b/eli5_what_is_a_database_and_what_is_sql_language/ | {
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"A database is a place to store data.\n\nSQL or Structured Query Language is a specific language used to do things (query) with the data. This includes things like selecting records created between given dates or updating a record that matches given criteria.\n\nDatabases are the backbone of most of the world at this point, everything is driven by data, every website, every piece of software. This being the case, the database software itself is incredibly valuable. The commercial ones tend to be the ones that are the most stable/best support/best for LARGE data sets.\n\nI hope this helps, I can clarify if you would like, I live in the data.",
"A database is just a very organized way to store any kind of data. The main benefit of storing data this way is that you can query (look up) the data fast, and you can connect or filter data in interesting ways. For example if you had a database of sales information, you could do fairly simple things find out how much money you were taking in each day, or track your inventory of any given product so you know when to buy more of them. You can also do data mining, which is trying to find interesting connections in your data that might be useful to you. Like you could look at people that purchased a large list of items one day, and then a single or small set of items the next day. This seems like a case where people forgot they needed something, and had to come back the next day to get it. Maybe you then put some of those frequent items right at the checkout line to remind people that they might need it, and they should just pick one up in case.\n\nSQL stands for Structured Query Language, and that's exactly what it is. It's a very organized language that you use to build a query that will find you information. It's similar to how you need to write in a programming language to write application for a computer, but in this case it's a language specifically to look information up in a database.\n\nAs for why some of them are more expensive than others, that's because some of them (Oracle being one of the leading examples) are really built for the truly massive systems that large corporations run. It's like the difference between a pickup truck and dump truck. Sure they both can carry cargo just fine, but you really don't want to try to use a fleet of pickup trucks when you could just use a dump truck instead.",
"A database stores data. Usually, this data is in the form of tables. A table might look like this:\n\n UserId Username Age\n 1 mac 40 \n 2 bob 27 \n 3 doug 25 \n\nDatabases can have hundreds or thousands of tables. The data is usually related. A website for buying candy might have a table for all the candies, a table for users, and a table for orders. SQL is how you talk to the database, it's a structured language for pulling the data you need. For instance, you might say \"I need to know all the orders that were sent to Kentucky last month\". But the DB doesn't recognize that, so in SQL it would be something like:\n\n Select orderNum from Orders\n where orderState = 'KY' and\n orderDate between '6/1/2013' and '7/1/2013'\n\nThat should give you a list of all the order numbers that fit the criteria.\n\nThere are plenty of free solutions that will give you the ability to build databases and query them; the money comes in when you add features like auto-backup of databases, query efficiency analysis, automatic rollover, database syncing. Stuff like Oracle and MS SQL server offer these extras, the more you need (and bigger your business), the more expensive. \n",
"The more expensive databases offer robust clustering and failover systems that can be missing, sketchy, or complicated to set up with the free databases. Also, with the expensive ones, you have someone to call and bitch at when your database breaks.",
"In short, a database is a place to store data - usually the database will be used by a computer program of some description, and often it allows that data to be shared across a network in a safe, efficient way.\n\nA database is not the only way, nor even the simplest way to store data. The simplest way to store data is to create what is commonly known as a 'flat file' - to make a flat file, all you need to do is decide which separate pieces of information you need to store and you essentially store it all in one big table in a file (like a text file) of your choosing. This has one major good point - it is very easy to write code which does this. However, it has a lot of bad points. The main ones are:\n\n* To retrieve any data from your flat file, you must load the entire thing - if you have a lot of data to store, loading a big file can take a long time.\n* If what you are storing is in any way complex, you are likely to have a lot of repeated data in your flat file -2 we call this redundancy, and often this is quite bad, especially in combination with the first point\n* It is difficult to share this file over a network\n* If you do share the file over a network, there is no guarantee that every computer will read the flat file correctly\n* And if you do share it over a network, protecting the flat file from bad people who want to change or destroy your data to fulfill their nefarious desires suddenly has to be managed by the person who writes the program which uses the flat file\n\nSo you can imagine that there is good reason for making something better. There are also other file-based storage systems like XML which I will not go in to right now - but they have their own positives and negatives too.\n\nSo what is the main difference between a flat file and a database? The thing that really allows all the benefits of a database usually comes down to the fact that the database is basically its own program which provides an interface, a particular way of talking to, the database. This is good because it allows the program which access the datatbase to be lazy about what data it wants to get at, in that it can ask the database for a single piece of data, and that single piece of data is all it will get. If you wanted to store information about countries, and you just wanted to know about Belgium, with a flat file you would have to load all of the information about Greece, Holland, Uraguay and the other 200+ countries in the world. With a database, you can just ask for data on England and that is all you will get (although it won't help you learn about Belgium).\n\nDatabases also have ways of reducing redundancy. This is done by storing data in multiple tables, some of which represent 'relations' between objects, and some represent 'entities' which you can think of as real world objects. A relation is some special connection between two things. Relations give you a lot of flexibility, in that they allow you to represent connections between multiple things in nice, non-redundant ways.\n\nAs databases are essentially just software programs in their own right, this allows them to also manage which people are allowed to look at and modify the database which is very good if you need to keep your information secret and safe, which many companies do.\n\nSQL is the interface that I alluded to earlier. SQL, as I'm sure has been pointed out before, stands for Structrued Query Language and is sometimes pronounced as \"sequel\" or if you're my friend, \"squirrel\". The idea behind SQL is that it allows you to express very complicated rules for looking at data and changing data in a database in a fairly simple, human readable (and writable) way. For instance, say you wanted to get all of the data from a table in your database, the code to do that in SQL is just:\n\n SELECT * FROM table\n\nIt's as easy as that. The only really difficult part about that might be the *, which just means \"get everything\". Of course SQL provides a lot more functionality than that - a more complicated statement might be:\n\n SELECT weight FROM wrestlers WHERE belts > 5 ORDER BY age\n\nAnd another way of reading this is just \"give me all the weights of wrestlers who have earned more than five belts in order of their age from youngest to oldest\"\n\nThe reasons for some databases being more expensive than others comes down to a few factors (and I'm not a big enterprise database expert or anything, so some of this is speculation) - but they might work better with other bits of corporate software, the company making the database might be more willing and capable to take liability if something goes wrong, the software is just more well known in big companies, it might be faster or require fewer computational resources to manage a large database and the feature set might be better. For instance there is a version of SQL called PL/SQL and the idea behind that is that as well as supporting normal SQL, it has a whole other layer that is more like a normal programming language on top of it.\n\nAlso Oracle SQL is horrible (opinion ;)).\n\nEdit: Structured query language. Not standard. Also I got 50% in my databases module. Take salt and lots of it. ",
"Cost with enterprise level databases (and really most enterprise software) has to do with technical support contracts that often go with it. It costs a lot of money, but you are usually entitled to professional product support as well as being kept up to date with necessary security patches and updates. ",
"Think of a database as a filing cabinet, which can be used to store massive amounts of information in an organized an methodical manner. Since several databases can connect with one another, think of them as a series of filing cabinets right next to each other. When you go to look up some information, you can find right where it is easily and quickly, as well as information pointing to other files that may be used in reference.\n\nSQL is a language used to navigate databases. Think of it as a secretary that knows right where every single piece of information is stored. You ask the secretary to get what you need and she grabs all the correct information for you."
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fix18h | how does a "new" disease suddenly appear and spread in such a short amount of time? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fix18h/eli5_how_does_a_new_disease_suddenly_appear_and/ | {
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"There is an enormous “reservoir” of potential pathogens out there in the world, constantly spreading and mutating.\n\n* Many can’t make the inter-species jump to humans because they work on biology that we don’t have.\n\n* Some that can make the jump only result in mild symptoms and get lost in the “noise” of run-of-the-mill fevers and flu.\n\n* Some that can make the jump are caught early and eradicated or quarantined by the international medical community.\n\n* Some that can make the jump burn through the human host population too quickly to spread very far.\n\n* A few can make the jump and are not so lethal that they can spread through the population.\n\nIn general, people should practice good hygiene and not go “turning over rocks” (e.g., clearcutting jungle, digging in permafrost, living in close proximity to waste or animals) to minimize contact with new variant diseases."
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ci0p5n | why are people rioting in hk? what does extradition mean and how would it affect the people? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ci0p5n/eli5_why_are_people_rioting_in_hk_what_does/ | {
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"An extradition agreement is a policy signed by two countries that basically declares that each country is not a legal \"safe haven\" from each other. For instance, if you're wanted in the US, and you flee to the UK, the police in the UK can arrest you and ship you back to the US to stand trial. Most extradition treaties have a clause where one country can revoke extradition if they believe that the suspect's human rights are being violated (in this instance, the UK could demand the return of someone they extradited to the US if they have a legitimate concern that the prisoner is being tortured).\n\nThe extradition treaty that was proposed between Hong Kong and China was essentially one-way, so the government of China could issue a warrant against anyone in Hong Kong (but Hong Kong couldn't issue a warrant against someone in China), and there was no provision protecting the human rights of the extradited prisoners. Basically, if the extradition treaty had been agreed to and signed, China could have started just forcing the Hong Kong government to send people from Hong Kong to China and 'disappear' them without consequence."
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3uqs1m | if bone is 5x stronger than steel then why can you break bone with steel but cant break steel with bone? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3uqs1m/eli5_if_bone_is_5x_stronger_than_steel_then_why/ | {
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"Is the question even valid: IS bone 5x stronger than steel?"
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p77n4 | drm in videogames | and why game creators keep insisting on putting it in their games, even though it appears to make more people want to pirate the game. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/p77n4/eli5_drm_in_videogames/ | {
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"The publishers care about how many games they sell. Anything they can do to delay how quickly people are able to pirate it, they will do. Because they know many people will say \"Oh, that looks like a game I would like. Can I pirate it right now at this moment? No?! Well I want it right now, so I guess I'll just go buy it\". The longer people are unable to pirate it, the more likely they'll just say \"Fuck it\" and put down some actual money for it. Increasing sales."
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4eu9n4 | how was so much information able to fit in such a little rom size on the n64 cartridges? | So I was playing Conker's Bad Fur Day on an emulator and I realized how small the ROM was! About 70mb! How was it possible to fit a full voice script, music and other sounds, textures, etc. With that little space? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4eu9n4/eli5_how_was_so_much_information_able_to_fit_in/ | {
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"Textures were low resolution and reused. Sound bites were reused, and probably not exactly CD quality. The best however is the wavetable synthesis they used for music - recorded instruments are used and replayed at different pitches in order to create a somewhat realistic instrumental soundtrack with very small files. ",
"Lower quality everything. \n\nThe resolution was lower so textures required less space, audio was more compressed and not cd quality.. music was midi and not recorded.\n\nMost of space increase usually comes from the increased quality of assets\n"
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3qtoo5 | the similarities between different languages. | Languages come from different places all over the world and have existed for a very long time. So why do so many use characters, spaces between ideas, and different lines that can be read across? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3qtoo5/eli5_the_similarities_between_different_languages/ | {
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"Languages are not equal to writing scripts. A lot of languages in the world were at first only spoken languages but they then came in contact with a civilization in possession of scripts and they learned from them and started writing their languages in the script which they came across. That's why a lot of languages in the world are seem to be written in similar ways because usually the script are either the same or have same source. Almost all European languages uses Roman alphabet and all north Indian languages + Tibetan uses Devnagri script. "
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brr4ue | how come a foot or two of brick/plaster can stop a cell phone signal but (moderate) hills and densely packed buildings in urban areas do not? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/brr4ue/eli5_how_come_a_foot_or_two_of_brickplaster_can/ | {
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"Hills and buildings in urban areas do block cell phone signals. A Lot. \n\nIn cities cell companies put relays on the tops of buildings to spread coverage from the main towers and prevent dead zones. \n\nIn areas with hills they will but relays or towers on said hills. \n\nBut in both cases you will have bad coverage in some parts of a city, and you will have hills making dead zones in rural areas.",
"A phone signal (or any EM radiation) is fundamentally the same idea as a flickering light. A light will shine through some materials, and bounce/reflect off and around objects in an otherwise open space. Your phone signal acts similarly."
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37o4mz | why aren't laughs different in the same way languages and accents are? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/37o4mz/eli5why_arent_laughs_different_in_the_same_way/ | {
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"They absolutely are. It might be harder to detect because, well, it's a semi-involuntary sound, but there are, in fact, different \"laughter\" dialect.\n\nAnother point is tat laughter hardly ever needs translation, so... "
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6l1b01 | does the concentration of a medicine one takes matter? | If I am taking tylenol for example. Will the effect of the pill vary depending on whether I take the pill as is, dissolve in 10 ml water and drink it or dissolve it a gallon of water and then drink it?
If it does why does it have an impact when the dosage is the same? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6l1b01/eli5_does_the_concentration_of_a_medicine_one/ | {
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" > If I am taking tylenol for example. Will the effect of the pill vary depending on whether I take the pill as is, dissolve in 10 ml water and drink it or dissolve it a gallon of water and then drink it?\n\nIn that case not really because ultimately it gets dissolved into the volume of your body. Some medications are not water-soluble so you would get poor absorption, but those are a fringe case."
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1hp2ig | how did the act of hugging evolve? | I've always wondered about this. I mean, I get that physical closeness/contact has an evolutionary component, as well as affection and nurturing behaviors -- but how did the distinct act of hugging develop?
I just imagine the first hug being super awkward, you know? Like, "I love you so much, I'm just going to press my body against yours for a minute." | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1hp2ig/eli5_how_did_the_act_of_hugging_evolve/ | {
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"Hugging was mainly just to keep warm I believe. Most animals will do it for that purpose (sorry people who think their kittens are snuggling with each other to be cute - they just want warm!)",
"Unfortunately, any evolutionary explanation for this is going to amount to a just-so story. The only valid answer at the moment is \"we don't know\". However, there's no particularly strong reason to believe that it's anything to do with biological evolution at all, or that hugging is even adaptive.",
"This is just a wild guess, but when babies are born I assume they find comfort in being cuddled because it kind of replicates the comfort of being in the womb. I like hugs because I still find comfort in them, so maybe it's just something that's stuck with us?",
"It's likely related to childcare instincts. Mothers carry their young around so they can be safe, warm, and fed. That creates a bond of comfort and closeness. \n\nA hug illicits those same feelings."
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69pk78 | why are some albums not on spotify, even though the artist mostly is? | For example, Chance the Rapper has pretty much all of his music on Spotify except his album Acid Rap. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/69pk78/eli5_why_are_some_albums_not_on_spotify_even/ | {
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"This is due to licensing deals that regulate when an album can escape exclusivity of platforms and other providers. \n\nI've seen a lot of albums go up on itunes or Tidal or something and take a few weeks to show up on spotify. \n\nThe reasons why they do this are many, but mostly around the royalties and moneys made from streams on certain platforms. They may get an incentive to be exclusive to one, or exclusive to a retailer or distributor with physical copies in advance of a stream release. "
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8pbzr6 | how was anne boleyns body identified? | In 1876 under queen Victoria the body of Anne Boleyn was recovered and buried properly under marble only what method did they use to identify her? She had no living descendents and I don't think they could have had the ability for DNA testing at that time anyway.
She was buried in a arrow box in a unmarked grave only i don't understand. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8pbzr6/eli5_how_was_anne_boleyns_body_identified/ | {
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"Basically it was the only female skeleton found in the area where her body was supposed to be, therefore they identified it as Anne."
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29t742 | how and why do june bugs only come out in june, and then magically disappear? | Where are they when it's not June/early July? I hate these things!!! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/29t742/eli5_how_and_why_do_june_bugs_only_come_out_in/ | {
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"Well shit I never actually thought about this, now I really want to know ",
"It has to do with the short life cycle these bugs have. Most of that time is spent as a grub. They live in leaf litter or even underground during this time. You might even see one but not recognize it as a June Bug. Eventually they pupate (sort of like how a caterpillar changes into a butterfly, only not as pretty at the end), and become the ugly bug you see flying around. They mate, lay eggs and then die. So the June Bug is there all year round, just not in beetle form.\n\n"
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d8yzso | how did excess oxygen in the atmosphere cause a mass extinction of species? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d8yzso/eli5_how_did_excess_oxygen_in_the_atmosphere/ | {
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"2.5 billion years ago(Earth is roughly 4.54 billion years old) most bacteria was anaerobic, meaning they didn't use oxygen for energy. There wasn't animals or dinosaurs, just mostly a bunch of bacteria and some kinda plants that didn't make leaves, mostly in the ocean(land wasn't populated with too much). A new type of bacteria started in the ocean named Cyanobacteria aka blue-green algae. Cyanobacteria uses sunlight to form chemical reactions in it's body for energy, the byproduct of those reactions are oxygen. Oxygen, to almost everything else alive on the planet, was poison. Which I know that's kind of a wired thought, but oxygen burns stuff, rust is basically oxygen burning iron. The fact that we animals breathe it is kinda bananas. Cyanobacteria just took off and multiplied like crazy, making A LOT of oxygen. Because if this, oxygen saturated the ocean(killing most anaerobic bacteria), bonding to everything out could, including minerals, especially iron (it's what helped us know that it did indeed happen, though geology) until it finally started accumulating in the atmosphere. Oxygen molecules bonded with the greenhouse gasses like methane, which created carbon dioxide instead, which is a problem because the methane was keeping the Earth nice and toasty, and carbon dioxide isn't nearly as good as methane in keeping the planet toasty, so an ice age/mass extinction happened. Those organisms that could use oxygen gained an advantage and it's been team oxygen ever since, except like, at the bottom of the ocean where those team anaerobic scrubs still hang out."
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aw74bo | b-cells and t-cells | What is the whole process of how B-cells, T-cells and dendritic cells react when there is a foreign antigen in the body? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/aw74bo/eli5_bcells_and_tcells/ | {
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"Think of antigens as metal dog tags. Dendritic Cells and Helper B-Cells can take metal dog tags and present them.\n\nDendritic cells consume (phagocytose) foreign cells (e.g. bacteria) and present the antigens to cytotoxic T-Cells. After they costimulate (come together), the cytotoxic T-Cell secretes cytokines (interleukins). Cytokines are small proteins that effect other aspects of the immune system.\n\nOn the other hand, Helper B-Cells do the same thing as a dendritic cell, but they remember the dog tags. They present T-cells with the dog tag, and T-Cells will release cytokines. However, B-Cells then selectively replicate (based on their memory) so that they may produce antibodies against the specific antigen that they presented (antibodies mark cells that have the metal dog tags that they presented). Think of antibodies as a metal detector.\n\nNow, think of the T-Cell as a bouncer. It will look at the metal dog tags and call for backup if something doesn't belong in the body. In this case, it will initiate an immune response (via cytokine secretion). These cytokines stimulate or inhibit the activation, proliferation, survival, migration, and differentiation of cells (they regulate cells other immune cells). Cytokines are the backup signal.\n\nFor the sake of brevity, we can split this up into six steps.\n\n1. Dendritic Cells or B-Cells phagocytose cells that have foreign antigens (NOT your body's cells)\n2. They present the antigen (metal dog tags) to cytotoxic T-Cells and costimulate (they work together)\n3. Cytotoxic T-Cells release cytokines to initiate an immune response (via regulation of cells)\n4. B-Cells, if used, are activated for clonal expansion\n5. B-Cells secrete specific antibodies (metal detectors) for the antigen (metal dog tag) that they initially presented\n6. Antibodies attach to cells with the specific antigen, and other immune cells eat them up\n\n & #x200B;\n\nSO...\n\nDendritic Cells = Present dog tag antigens\n\nHelper B-Cells = REMEMBER and present dog tag antigens\n\nCytotoxic T-Cells = Scan the dog tag and release cytokines\n\nCytokines = Recruit signal for help/backup from other cells (immune response)\n\nAntibodies = Secreted by Helper T-Cells. Detect cells with specific dog tags and mark them so that they are killed\n\n & #x200B;\n\nedit; grammar ",
"Dendritic cells (and macrophages, and sometimes B cells) suck up the invader, grind it up, and stick bits of it on their outsides. They then head to areas where lots of T cells are hanging out/passing through (the lymph nodes).\n\nAll the T cells passing by will check it out but nothing much happens until the T cell that has the perfectly \"fitting\" receptors comes by. When this happens, it starts making tons of copies of itself. Some of them go out and start raising the alarm to attract a bunch of other nonspecific immune cells to the area. Some of them start going out and spraying the invaders with deadly chemicals.\n\nMeanwhile, the B cells have been activated in the same way or have just stumbled upon the foreign invader themselves. When one that matches the antigen perfectly finds it, it also starts multiplying like crazy and turns into something called a plasma cell. \n\nThese plasma cells start producing massive amounts of the same receptor it used to detect the antigen in a form that it can \"shoot out\" into the body fluid. These are antibodies, and they latch on to the invaders and act like flags for friendly white blood cells to find and eat them, or disable key parts of their molecular machinery, or just stick them all together into a big clump. "
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27zzfy | based on history, roughly how much of science as we know it is *wrong*, and will need to be corrected in the future? | Science isn't absolute truth, it prides itself on not being correct. Based on its history of correcting itself with new information what fields are likely to be..."wrong", so to speak?
Is there a difference between science being "wrong" and a new discovery being made or is it all kind of blurred together? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/27zzfy/eli5based_on_history_roughly_how_much_of_science/ | {
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"_URL_0_\nQi says that approximately 7% of facts become out of date and 'wrong' each year",
"First we have to make a distinction between the history of humanity's understanding of the world and how it works, which covers thousands of years, and the history of the modern process of scientific discovery, which is a couple hundred. It's true that much of what we as a civilization used to think has been proven wrong later, but since the beginning of the modern process of science and the scientific method, very little has been shown to be wrong.\n\nLet's look at Newton's laws of gravity, which have since been 'replaced' by Einstein's. Was Newton wrong? Well, not exactly. The difference between Einstein's and Newton's equations is that Einstein's have a term that accounts for relativity. But in non-relativistic situations, that term becomes negligibly small, and the equations end up the same as Newton's. So Einstein didn't show Newton to be wrong outright, but that there are situations where they have to be adjusted. And these situations were ones that in Newton's time weren't known about and we didn't really have to equipment or technology to look at or test.\n\nSo what happens in science isn't that one discovery is completely invalidated and replaced by a new one. What happens is that as science and technology advances, we are able to look at new conditions and situations that we couldn't before, and then test if our current laws work in those new situations. But for a law to be shown to be wrong for conditions that are well observed and tested, that is extremely unlikely. Just think about all the technology that's based on science. If it's wrong, why does that technology work?\n\nOne problem is that the media is very bad at covering science news, so they can often give the impression that things are being proven wrong and changing all the time. A lot of new discoveries are widely reported in the media before those experiments have been reproduced independently by other researches, or sometimes even before any papers of that discovery have been peer reviewed and published. So then if problems are identified in the methods or conclusions of that experiment, the media does a follow-up report saying that the previous science has been shown to be wrong. But in the scientific community, the initial discovery was never considered to be right in the first place.\n",
"Don't forget - science does not prove something to be correct. It lends support to one hypothesis or another. When repeated testing, or multiple hypothesis point to a unifying set of concepts and ideas we coin this a \"theory\" - theory of gravity, theory of evolution are backed by millions of experiments and testable hypotheses that do not contradict, but rather lend support to the same conclusions. \n\nWhile a hypothesis can never be proven, it can be disproven through testing. If a hypothesis is disproven than we might look at why it is incorrect and try and figure out an explanation for our observations. We might go back and try and test new hypotheses. "
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1vme5e | why does smell of weed seem to permeate even the most tightly wrapped container? | You know. The scientific explanation. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1vme5e/why_does_smell_of_weed_seem_to_permeate_even_the/ | {
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"Usually, odor-causing agents from the weed got onto the outside of the container before you sealed it. If it's airtight, you can wash the outside of the container after filling it, this should reduce the odor greatly.",
"The odorous compounds in weed are non-polar oils. As such they tend to pass relatively freely through plastic containers. If you confine it in a polar container (glass bottle) it will smell a hell of a lot less as long as, like dig machine said, you keep the outside relatively clean."
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3o2ogv | why do people think we can transform mars when it has no magnetic field? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3o2ogv/eli5_why_do_people_think_we_can_transform_mars/ | {
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"solar wind stripping away an atmosphere happens over geologic timescales and wouldn't really hinder our terraforming efforts. The lack of a magnetic field does result in very high surface radiation levels which would be a problem, but not an insurmountable one.",
" > As far as I know, a prerequisite to having a habitable planet is that it has a magnetic field to prevent solar wind from stripping the atmosphere\n\nAtmospheric bottling *is* a problem, but it's a long-term problem.\n\nThe short-term problem of no planetary magnetic field is that planetary magnetic fields shield the surface of the planet from highly energetic, and very dangerous, cosmic rays.\n\nIf you take a scintillator tube (a specific type of crystal that glows when radiation passes through it, connected to a machine that turns light into electrical signals and amplifies them) and just leave it sitting out, you'll get a reading roughly every 5-7 seconds of a cosmic ray passing through it.\n\nEven with our geomagnetic field, some cosmic rays still manage to get through.\n\nHowever, without the field, many, many more cosmic rays will come sleeting through everything on the surface, doing damage to genetic material they hit."
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57shts | why is football the only one of the four major american sports in which the referees give big speeches about penalties and such? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/57shts/eli5_why_is_football_the_only_one_of_the_four/ | {
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"They just explain it instead of the announcer....I wouldn't really call it a big speech lol",
"Hockey has announced penalties, just like football. There are hand signals for the time of the penalty, but it's then announced.",
"The difference is that in football, a lot happens at once and the infraction can occur with any player. When a flag is thrown, it's often unclear why. \n\nWith other sports, the action occurs with the ball or puck and events happen in sequence. The call is usually understandable with a single gesture. \n\nIn baseball the pitch is a strike or a ball, a hit is fair or foul, the runner is safe or out. \n\nBasketball and hockey, it's a goal or no goal, offside or not, interference or some other physical penalty. \n\nIn football the penalty is not only a gain or loss of yards but also undoing the entire last play. If I ran the entire field, flipped over 3 guys and scored a touchdown and the ref said, \"nope, doesn't count, go back and do it again.\" I want to know why. If it turns out that a teammate at the other end of the field crossed the line before the ball was snapped, I'd at least understand why my last effort was for nothing. ",
"For one, there is a long list of penalties in American football. This necessitates on-field explanation as any one of these numerous fouls could occur on any play. More importantly, many of the punishable offenses also occur \"off the ball\" which means that the audience will likely not be paying attention to the part of the field where it has occurred. The most common example would be offensive holding which is generally called against the interior offensive linemen on running plays. Both the audience and the cameraman for the tv viewership will be focused on the ball carrier, not the linemen. So, when the penalty flag comes out, it's a good bet no one other than the official has seen what happened. ",
"In addition to the generally accepted answer that there is more happening at once on a football play, over the last few years football umpires have been doing more explanation as to why it was a penalty and the circumstances that caused the flag, the penalty it self, the players involved, the amount, the decision of the other team to accept or decline, the result, and a warning that an offending player may be ejected. Go back a few decades and nearly everything was only hand signals, the same ones still used today. ",
"Unlike, basketball, baseball, or hockey, in football, the opposing team can accept the penalty and replay the down with the yardage improvement, or they can decline the penalty and accept the result of the play. So from the hand signal alone, spectators don't know the opposing team's decision or the result of the penalty (yardage or downs or half the distance to the goal line, etc.)",
"Football has a few unique factors that lead to this:\n\n- there are 22 players on the field for every play, which can be tough to follow all at once. Which one broke a rule? I don't know, I was watching the one with the ball. \n\n- there are a whole lot of rules in football. It's genius isn't in simplicity, like with European football. So there are a lot of ways to break the rules, more than any fan or ref would like to learn hand signals for. (Fun fact, they do use hand signals anyway.)\n\n- all those different rule infractions result in different penalties. One may cost you five yards from the end of the play, while another may cost fifteen yards from the spot of the foul and the down you were playing. That's the difference between \"first and 15 on the 45 yard line\" and \"second and 23 on the 37 yard line.\" So someone has to clarify what the penalty cost and where the next play starts.\n- the clock also stops and starts all the time in football, so often after a call the refs need to clarify how much time is left on the clock. \n\nTLDR: its a complicated game with a lot of rules, so we Le the refs explain what happened. ",
"Hockey referees will announce the penalties as well. They usually indicate whom incurred a penalty with a hand signal and will verbally let the score keepers know.\n\nAfter that they turn their microphone on, similar to an NFL referee, and announce the call.",
"I think it's the complexity of the rules. In the other sports, it's often obvious why a call was a made. For inexperienced football viewers, not so much.",
"Can you give an example of a football ref \"explaining the play\"? Usually it's just something like \"Holding, on the offense, number 71,10 yard penalty, repeat first down.\" \n\nI guess you could say it's explaining the play, but really it's just giving the minimum amount of information. The penalty was holding. It is called against the offense. Player number 71 was the guilty party. It is a 10 yard penalty. The result of the penalty is that it is still first down. ",
"I should point out a lot of fans already think baseball umpires SHOULD have a means of verbal communication with the crowd/viewers because so many weird plays with complicated rulings can happen.",
"Source: my dad is an NCAA referee. \n\nThey explain everything because the rules are often multifaceted, have different outcomes and different meanings depending if offense/defense.\n\n What hasn't been said is that there is a conscious effort to expand the explanation because of the popularity of the sport (and more people who don't know these rules). You can notice this with how much more everything is explained in the divisional championship games and Superbowl. "
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532hmf | why is the flushing mechanism different in a household toilet compared to public restrooms with multiple toilets? | In a household toilet, there is a tank above the bowl that holds water to refill the bowl after flushing. The flush lever connects to a chain which opens a rubber seal and begins the flushing process. Why is this not used for public toilets? What mechanism do those use? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/532hmf/eli5_why_is_the_flushing_mechanism_different_in_a/ | {
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"Public restrooms get more use, and more frequent use. It is not uncommon for it to be occupied almost immediately after a user leaves the stall. As such it is more efficient for them to have a tie directly to the water main rather than to fill a tank. Also it means there is less for someone to tamper with, which will happen with a public toilet and so less chance of something breaking and costing you money to fix. ",
"A simpler explanation, though not the best answer, is that a public toilet with a tank will eventually become an upper decker. It'll take the building time and money to clean it. No one wants that...",
"I think it's also important to note, that those tankless toilets require bigger water line. You can have a clogged up 1/2 line for a regular tank toilet, but will need a bigger 1\" line for the commercial one."
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63aksm | with the ubiquity of flash drives, why do so many software programs still have the floppy disk as the icon for saving a file? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/63aksm/eli5with_the_ubiquity_of_flash_drives_why_do_so/ | {
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"It's an interesting design problem. There are two issues here. \n\n1. Saving a file no longer corresponds to *any* physical device. It could be on a cloud drive, an SD card, a hard drive, an SSD, just about anything. That's hard to draw.\n2. The very concept of saving a file is obsolescent. Modern computer systems have enough power and storage that \"save\" is starting to go away as a user interface concept in many programs.",
"\"Save file\" is an abstract concept.\n\nCalling a sequence of data on a disk a \"file\" is an abstract concept that doesn't reflect reality either - how many people keep filing cabinets around anymore?\n\nCalling a hierarchical portion of the storage system a \"file folder\" is an abstract concept in the same way.\n\nCalling the screen of your operating environment a \"desktop\" is a metaphor for an abstraction. Calling the area used by a running program \"window\" is an abstract metaphor.\n\nThey're all abstract ideas & the metaphors we use to describe them don't need to constantly be updated as the things they refer to become obsolete. People are now growing up thinking of \"files\" and \"folders\" primarily as computing concepts & secondarily as the physical things they refer to. There's nothing to be gained from coming up with a new symbol - being standard & widely understood is far more important than being accurate.\n\n...and as /u/Concise_Pirate says, there's no single icon you could even pick these days. The floppy disk hasn't been accurate for a long time - hard drives became commonplace before GUIs became widespread."
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1qe4u5 | how is this year's christmas shopping season 6 days shorter? | The media is saying for the US, the Christmas shopping season is 6 days shorter and it's essential that retailers do what they can to make up the lost time. How did we lose 6 shopping days? We had 365 days last year (366 actually) and we have 365 days this year. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qe4u5/eli5how_is_this_years_christmas_shopping_season_6/ | {
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"The Christmas shopping season is generally considered to start in earnest on Black Friday (the Friday after Thanksgiving). Thanksgiving is always on the last Thursday in November, which means that the day of the month it occurs on changes depending on which day of the week the year started on, and whether or not it's a leap year. This year, Thanksgiving is on November 28th. Last year, it was on November 22nd.",
"The Christmas shopping season goes from Black Friday to December 24th. Black Friday can be anywhere from November 23rd to 29th. Thus, when Black Friday is on November 23rd, the shopping season is 32 days. When it falls on the 29th of November, the shopping season is 26 days. "
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98q98x | what is poor eyesight? what in your eye is making you see things blurry? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/98q98x/eli5_what_is_poor_eyesight_what_in_your_eye_is/ | {
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"From what I understand a common problem is the lens in your eye not focusing light at the right place.\n\n(Not a doctor, never stayed at a holiday in)",
"Basically, your eye is a round ball, with jurist a little hole to let the light in. Because it is perfectly round, the light goes, zing, straight in without changing its path when entering through the hole.\n\nFor certain people, the eye is not very round (like mini tomatoes, some a perfectly round, others not so much). This is because the liquid inside the eye is pushing pushing pushing against it, or because the muscles right over the eye are to heavy. The deformation of the eye ends up changing the course of the light when it enters the tiny hole in the eye, and instead of going straight ahead, the lights turns at angles it shouldn't when entering.\n\nThis is why you see blurry. Basically, bad eyesight is a lack of focus in vision.\n\nSorry for the stupid way my explanation is written, but I tried to take the 5yo part into account.\n\n",
"There are a variety of things that can cause poor eyesight. The human eyeball has a lens, and that lens causes the light entering the eye to focus on a collection light sensitive nerves, called the retina, at the back of the eye. Most (but not all) causes of blurriness are caused by the focus of the lens being wrong.\n\nThe lens is a flattened disk-like shape, and it is stretchy. There are muscles attached to the perimeter of the lens that make the lens thinner or thicker. Changing the thinness or thickness of the lens changes it's focus. A thin lens means far away things are in focus, and a thick lens means close up things are in focus.\n\nWhen you have myopia, or nearsightedness, the lens is actually too strong. It focuses the image not ON the retina, but in front of it. Even at the maximum stretch, the lens does not thin out enough to bring the object into focus.\n\nHyperopia, or farsightedness is the opposite problem. The lens of the eye focuses the image not ON the retina, but behind it. Even at its thickest, the lens is not thick enough to bring the object into focus.\n\nThere is another condition called astigmatism, where the lens doesn't stretch evenly. Instead of focusing the entire image on the retina, parts are focused in front of it, and parts behind it.\n\nThere are other parts of the eye that can also cause problems. There is a clear protective layer called the cornea. If the cornea is not round, you could also have astigmatism. If the cornea stops being clear, your vision will also no longer be clear. The retina can sometimes become detached from the back of the eye. The fluid that the eyeballs are filled with can become cloudy, or harden in spots, or there could be blood in it, all of which can cause blurry vision.\n\nLastly, there are also diseases and injuries that affect the optic nerve and the visual cortex of the brain. These can also cause you to have blurry vision."
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el5uda | if i was in a room made of mirrors, and i shut off the lights, why wouldn’t the residual light continue to bounce off the mirrors and illuminate the room? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/el5uda/eli5_if_i_was_in_a_room_made_of_mirrors_and_i/ | {
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"Mirrors aren't 100% efficient. Some of the light that hits them doesn't get reflected. But gets absorbed as heat (just like how the sun warms you up) so with each bounce there's less and less light left until it gets dark. And because of how fast light is this would be nearly instant.",
"Mirrors aren't 100% reflective. They actually absorb quite a bit of light, so after a few bounces it would all disappear. Afaik there is no 100% reflective surface. Mylar gets in the high 90%s,but even then in a room of normal size it would have bounced a billion times in a second, losing more light each time - at the speed of light.",
"You're working on the incorrect assumption that it doesn't. It would illuminate after the light turns off, the light would continue to bounce.\n\nFor fractions of milliseconds. \n\nEach time the light hits a mirror some of the light would be absorbed(Roughly 40%), each time it hits an object you want illuminated some would be absorbed(Maybe 90%), each time it hits your eye it would be absorbed (Probably 100%).\n\nThe speed of light is 29,980,000 meters per second. Let's say the room is 5 meters across. That means light would be reflected and the above percentages lost about 6 million times in a second. Effectively the light would be completely absorbed in about a millionth of a second, or about 100,000 times quicker than you could even see.",
"mirrors aren't really that reflective and the light would bounce so fast that even if a photon could bounce a billion times before getting absorbed that is still absolutely miniscule amount of time for something as fast as light.",
"It does, but only for an extremely brief time, as mirrors are not perfectly reflective. It takes light mere nanoseconds to cross an average room, so even if a mirror reflects 99% of the light that falls in it, the light in the room will be reflected millions of times per second and decay far faster than the eye can detect.",
"Mirrors are around 90% reflective, and particles need to be charged up with enough energy to release photons when they drop back down. A bunch of particles absorb energy from electricity and bounce up to higher levels and as they fall back down photons are released. at lower levels they release infrared /heat energy instead of visible light, and you need to keep feeding the lightsource energy or the light in the room will just get darker until it becomes infrared and heat."
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2qte35 | why does it suddenly feel like our hearts drop everytime we see or do something startling like a teacher calling us over to their desk? | Admit it, you got scared whenever a teacher called you over. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2qte35/eli5_why_does_it_suddenly_feel_like_our_hearts/ | {
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"The release of adrenaline (more accurately called Epinephrine) is a hormone released by your adrenal glands, preparing you for a fight or flight scenario. \n\nThe release of adrenaline speeds up the beating of our hearts and it's that fluttering sensation that makes it feel like our 'heart is dropping', when something scary or nerve racking is happening. \n\nEDIT: Grammar.",
"I get nervous every time the phone rings and i just had bad results in school.",
"You obviously cared way more about school than I did. "
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zzlba | how do hackers get caught so easily? to clarify why don't they just do their hacks from a coffee shop or other free wireless location? | The title pretty much says it. It just seems to me, how could you be caught if you were using a free location? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/zzlba/eli5_how_do_hackers_get_caught_so_easily_to/ | {
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"Hackers *don't* get caught easily. Unless they are very bad at computer security or piss off the NSA (or maybe the FBI), they basically never get caught. If you're bad at computer security, you're probably going to do something dumb like use an email account registered with your real name; if the federal government wants to find you, it's very unlikely that your use of Starbucks wifi will pose much of an obstacle.\n\nSo while it theoretically is a good idea, in practice it's pointless.",
"Ego. Very smart people have to brag about how smart they are to other smart people, sometimes the wrong people find out. Amarkov is right though, the vast majority don't get caught, even when a company knows about it, it looks horrible to customers/investors so they just keep it quiet.",
"The truth is that most people get caught because they are careless. \n\nFree locations have cameras which can contain images of you. If you visit the same one often, you become predictable and easy to find. You can be traced through your computer because of the information it leaves behind (regardless if it is spoofed). \n\nSpeaking from a black market perspective:\nMost have been involved in such activities long enough that they don't feel threatened. They do business openly with others which attracts the attention of undercover FBI agents. There are most certainly undercover agents in nearly every black market/ hacking community there is out there. A few people I know got caught for foolish reasons and it didn't require the FBI to do a lot of digging. They signed up using their regular emails, used their real names, etc. They got too trusting of the community and in an indirect way, it led to their downfall.\n\nIt is hard being 100% safe. You can attempt by having a burn computer, purchased without a paper trail. Make sure your face never gets on the cameras; there are cameras everywhere and even a tiny glimpse of you can lead to huge discoveries. Use a MAC changer, IP changers, sock5s, VPNs, proxies (all from other countries), which makes it much harder to trace. Stack layers of protection on each other and make sure you don't stick around in one physical location too long. The main thing is that you should never talk to any one about what you do. Never act suspiciously so that even if someone purposely (agent or not) watches you, they can't discern what you are doing. One small slip-up can provide a trail that G-men will pounce on.",
"Scary reality, hackers don't get caught easily.\n\nWhat people may or may not realize is the sheer size of the scary part of the internet, most of the attacks don't end up making the news. In fact while I don't have any real sources on hand, truly devistating are usually only notice when the damage becomes clear. Financially motivated cyber-crime is usually the most devistating, and because there's not necessarily an emotional attatchment to the target, there's no reason to give a victem a reason to freeze their bank accounts early.\n\nWhen I say most hackers don't get caught, the majority of financial criminals have no reason to maintain a public persona, and it's this public persona that gets people caught.\n\nIn most any online community people maintain an alias, I'm maintaining one right now as are you, however neither of us are likely to be overly protective of our details, as a result this alias becomes nothing more than an easily linked pseudonym instead of the potentially untraceable alternate persona that it could be, it's this that gets most hackers caught. An extremely recent example is the case of #Antisec and Jeremy Hammond (which I'm using because of the wide variety of articles on lulzsec, antisec considering how recent these incidents were) who was caught not because his IP was traced but because he wasn't careful about who knew what about him. Hector Monsegur, Sabu as Jeremy Hammond (anarchaos) would have known him who as we now know was turned an informant against the group he created was able to trace Hammond down because Hammond had mentioned his brother being arrested -- a major slip and a bad mistake, obviously it wasn't long before the police were able to put the details together and find the true identity of anarchaos.\n\nBeing arrested because of your computer being traced mostly doesn't happen anymore -- ironically it did in the case of Sabu, but this is from what the reports describe simply one slip, one careless mistake. For anybody who has the experience, knowledge and intelligence to commit acts of cyber crime that would be extremely public, disguising one's IP (an address to your computer) is less than trivial. Many services exist publicly which can allow anybody, of good intentions or bad, to remain anonymous on the internet. One could purchase their own server in a country such as china which is unlikely to cooperate with american federal agents, one could also purchase a variety of proxy services again in China or Russia, or for free one can use services such as Tor or i2p.\n\nCompare the number of criminals caught for cyber crimes versus the number committed, viruses for example, are not being created by one bored hobbyist (Mikko Hypponen has some very informative talks relating to viruses _URL_0_ is a good one). Mcafee had a really interesting analysis of the nature of cyber crimes, what is increasing, what is decreasing and it might be an interesting read.\n\nThis went on a bit longer than I intended, but basically the number of hackers you hear about each year are an extremely small portion -- the sharpest peak on the tip of the iceburg -- of the real number of hackers.",
"Computer crime isn't like what you see on TV, someone typing away for a few minute, then hacks happen. It can take huge blocks of time often at odd hours of the day, specialized equipment, and craploads of bandwidth.\n\nEven if your coffee shop had enough bandwidth and the right equipment, hanging out there 12 hours a day 7 days a week could be just as suspicious as hacking from home."
]
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[],
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"http://www.youtube.com/watch?v=cf3zxHuSM2Y"
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|
efoshh | how does the soil on farms regain its nutrients year after year of growing crops? | Wouldn't all the nutrients eventually leave when the plants are harvested and sent to market? How did farmers manage nutrients before fertilizer was common? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/efoshh/eli5_how_does_the_soil_on_farms_regain_its/ | {
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"You can rotate crops to rest and renew the soil. You can also let it be unused for a time or add organic matter like plant or animal waste. A lot of the plant matter would also be left behind.",
"If you keep on growing densely and don't use fertilizers, the soil will not have enough nutrients for growing a good crop for many years. Now, if you give it a break every couple years and let anything grow without touching it and then let whatever had grown die on the field, it will be broken down by insects and bacteria, bringing some nutrients.",
"I believe they cycled crops, for one. Different crops add and take away different things from the soil. One crop preps the soil for the next, and such. Other times they would leave the field fallow, unused for a while to regain some nutrients.",
"Soil organisms have a big responsibility.\n\nEarthworms play a huge role. They excrete waste in the form called castings in the soil that acts as an organic fertiliser containing important nutrients such as nitrogen and phosphorus. \n\nDung beetles, some of them burrow cattle dung into the ground where it is broken down by bacteria to release Nitrogen for plants in a form they can take up. \n\nSoil organism, both micro and macro help with decomposition. Which also releases nutrients.",
"The general answer is that for farmland that is more or less always in use for planting, the nutrients have to be replenished through purposeful human action of adding fertilizer.\n\nThere are traditional methods of fallowing the land (letting it \"rest\") but this means large parts of a farm left unproductive. Soil will recover nutrients naturally from decomposition, worms and other processes.\n\nDifferent plants require different quantities and variety of nutrients (some more this, some more that) and they will root differently (pull nutrients at different levels within the ground). Some can actually help pull nitrogen from the air and convert it into nitrogen form that other plants can use. This is one, of many reasons, that crop rotation is used (also to deter pests overpopulation) \n\nSome areas, famously the Nile, flood regularly and this helps bring fresh soil/nutrients back to the land. \n\nBut overall, from fairly ancient times, it is known that land can be depleted of nutrients if farmed constantly.",
"The short answer: it doesn’t.\n\nThe longer answer: back in the day, smaller farmers (and all farmers were smaller farmers) practiced something called *crop rotation*, which means if one crop took lots of nitrogen out of the soil, the next season, they’d plant something that put nitrogen back into the soil. They’d have several fields going with a rotation of different crops which would help the nutritional balance of the soil.\n\nNow, with modern monoculture farming (planting the same crop over and over and over again), this simply doesn’t happen and farmers have to add the nutrients into the soil artificially by spraying chemicals onto the soil and/or into the fertilizer as a soil additive."
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8kiduj | why is it that you can easily see the change in looks when humans is getting older, while other animals is almost looking entirely the same from young adulthood until death? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8kiduj/eli5_why_is_it_that_you_can_easily_see_the_change/ | {
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"Humans are adapted to be very good at differentiating between other humans and recognizing certain traits. For example you likely have a difficult time telling one crow from another but telling humans apart is easy. Crows similarly can easily recognize different crows but may confuse humans.\n\nIn this same way humans can easily recognize the differences between young and old humans, while recognizing such differences in other animals takes some knowledge and practice. They do look different if you know what to look for though.",
"I can easily see the change in cats, dogs and rats from young adult to elderly, because I’m familiar with their lifespan. To the same point, someone unfamiliar with humans would likely just think we all look the same, and not naturally associate more wrinkles with aging. "
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[],
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||
a93a1m | why is it that every winged animal developed wings on the forelimbs? | Bats
Birds
Reptiles
Every animal with Wings developed their forelimbs into wings. Why not the back limbs?
Why not have both winged forelimbs and winged backlimbs? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/a93a1m/eli5_why_is_it_that_every_winged_animal_developed/ | {
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"The flying squirrel has wings that encompass both the forelimbs and the back limbs.\n\nThe ancient reptile *Sharovipteryx* had wings on only its hind legs.\n\n\n",
"Let me introduce you to [Sharovipteryx](_URL_1_).\n\nGoofy gliding lizards aside; you need your wing to support you at your center of gravity for stability. Your wing also needs to be [thickest at the front](_URL_0_) to generate lift. So the front of the wing is where you have room for bones. \n\nPut together, that means the wing needs to start somewhere on the front half (by mass) of your body - thus, the front pair of limbs is the only option, short of investing a bunch of mass in a tail for a counterbalance or moving the rear limbs way forward. Flying creatures need to be light, so a bunch of mass in the tail (which doesn't help generate lift) is out. And moving the rear limbs forward is a much bigger change in body plan than wings, and thus much less likely to arise out of mutation."
]
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[],
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"http://www.petester.com/aeropics/airfoil.gif",
"https://en.wikipedia.org/wiki/Sharovipteryx"
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|
1lhtki | how come we have not found dino dna in a mosquito that was trapped in amber. as per jurassic park. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1lhtki/eli5_how_come_we_have_not_found_dino_dna_in_a/ | {
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"text": [
"It's like finding a needle in a haystack. More specifically, a mosquito in some random place on earth. Also, DNA degrades over time. We've had problems with wooly mammoth DNA and that's far \"younger\" than dinosaur DNA."
]
} | [] | [] | [
[]
] |
||
31vnml | does using a credit card really boost your credit rating? if so, how much of an effect does this have? | Is it worth it for everybody to start using a credit card over a debit card? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/31vnml/eli5_does_using_a_credit_card_really_boost_your/ | {
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"Yes, provided you're disciplined enough to pay the balance off in full every month, otherwise you'll worsen your credit rating.\n\nThe fact that credit card companies are profitable goes to show that mant people are not this disciplined, and probably shouldn't have a credit card.",
"Some of the answers to this question are disastrously wrong, and reflect commonly held misconceptions and misinformation. Credit cards are a mystery to many people, shrouded in magic and myth as to how they work behind the scenes and how to leverage them to your advantage. I highly suggest you go over to /r/personalfinance and start reading; they have sections dedicated to credit cards. This is not something you want to listen to ELI5 and act upon...\n\nStart [here](_URL_0_), and read through their articles. This is FICO, the company that makes the proprietary and industry standard credit score algorithm. If you want to learn to improve your score and leverage your credit, where better to turn to?",
"Yes it does, but the effect be disastrous if done incorrectly.\n\n1. Don't spend more on a credit card than you could with debit/cash. A credit card is not meant to allow you to spend above your means.\n2. Don't carry a balance. This is a VERY common misconception. Every month you get a statement with a balance due. Pay off that entire statement balance. Every month.\n3. Try to keep your total statement balances below 30% of your total available credit limit.\n\n/r/personalfinance is an excellent place to find more information, not only on credit card use but budgeting, saving, and preparing for retirement in general."
]
} | [] | [] | [
[],
[
"http://www.myfico.com/CreditEducation/articles/"
],
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] |
|
lwsqh | the hall effect [physics] | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/lwsqh/eli5_the_hall_effect_physics/ | {
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"If you put a magnet next to a piece of wire with current running through it, the path of the electrons are effected because of the charge of the electrons. If you could zoom in on the tiny piece of wire next to the magnetic, you'd see a high number of electrons on one side and a large number of \"holes\" on the other side. Thus, a voltage drop exists across the tiny width of the wire. You could also run current through any shape of metal/material and the electrons would get pushed to one side because the magnetic field. ",
"If you put a magnet next to a piece of wire with current running through it, the path of the electrons are effected because of the charge of the electrons. If you could zoom in on the tiny piece of wire next to the magnetic, you'd see a high number of electrons on one side and a large number of \"holes\" on the other side. Thus, a voltage drop exists across the tiny width of the wire. You could also run current through any shape of metal/material and the electrons would get pushed to one side because the magnetic field. "
]
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[],
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] |
||
6l0szj | what are the benefits of air-drying clothes other than the obvious electricity costs? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6l0szj/eli5what_are_the_benefits_of_airdrying_clothes/ | {
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"All that lint you find in the trap of a dryer stays in the clothes. I imagine this leads to clothes lasting longer. ",
"No idea what motivates Koreans or Japanese, but, assuming you live someplace with clean air, line-dried stuff smells amazing. The cloth gets much less wear and lasts longer. The fabric after drying is stiffer and has more body compared to from-the-dryer. Some of us consider this to be a good thing, at least for some items. If you ask for 'extra-crunchy' when you drop your shirts off at the cleaners, this is probably your style.",
"Besides being easier on the clothes, and the electricity costs, drying your clothes in direct sunlight works as a natural killer of bacteria due to the exposure to UV light, and will actually produce cleaner clothes, with of course the downside being the fading of colours, becoming \"sun washed\" for darker colours."
]
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[],
[],
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||
46xyib | i saw an article that says, "if you put a giant mirror 10 lightyears away from earth and looked directly at it with a telescope, technically you're seeing 20 lightyears into the past" - this seems to make sense but is it true? | Theoretically it makes sense but is it actually true? I'm sure there are other factors to think about. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/46xyib/eli5_i_saw_an_article_that_says_if_you_put_a/ | {
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"text": [
"Theoretically, yes. It would have to be a gigantic mirror that you could structure to focus the light specifically on the light that was reflected off the earth and everything on it.",
"You're seeing 20 years into the past. A light year is a unit of distance, not time. But yes it's true.",
"Yes, but after you got the mirror there you'd have to wait an additional 10 years before you saw any rejection. Even if you could get the mirror there at the speed of light it would be a total of 20 years from when the mirror left Earth before you could start seeing 20 years into the past. You could never use it to see what happened before you launched the mirror.",
"A mirror 10 lightyears away show 20 years in the past, not 20 light-years in the past. A light-year is a unit of distance (the how far light travels in a year), not a unit in time.\n\nBeing able to aim the mirror (a tiny fraction of a degree really adds up over 10 lightyears) and having a powerful enough telescope to get enough detail to really matter would be amazingly challenging and it would take a VERY long time to get the mirror over there (pretty much impossible by today's tech and it would take longer than your lifespan), but yeah, this is how it would work. \n\nIt is possible in theory, but the practical concerns of setting it up are beyond our grasp."
]
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|
6iidt3 | how can people with down's syndrome donate blood | If every cell in a Down's persons's body has chromosomal abnormalities, wouldn't their blood cells also be abnormal? Or would this even be an issue? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6iidt3/eli5how_can_people_with_downs_syndrome_donate/ | {
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"text": [
"Red blood cells do not have a nucleus, and therefore no DNA. Assuming that there is not a separate mutation/issue that impacts RBC production, their red blood cells would be normal. Not sure about other blood products.",
"Red blood cells do not have a nucleus therefore they do not have any chromosomes or DNA in them"
]
} | [] | [] | [
[],
[]
] |
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