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f7l6vu | when words are translated to english, how is the spelling of those words determined, and who makes the decision? | The question struck me while playing a game featuring a character named Ratonhnhaké:ton (pronounced Rah-Tone-Ha-Kay-Tun). Reading his name in the subtitles made me wonder how it’s spelling (using the English alphabet) was determined. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/f7l6vu/eli5_when_words_are_translated_to_english_how_is/ | {
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"It depends on the language. There are often standard or semi-standard ways of transliterating between different languages. (BTW the term is transliterate not translate). \n\nFor example, a standard way of writing Mandarin in the Latin alphabet is called Pinyin which has rules for how to write down the sounds in Mandarin. My first language is Urdu, there is a semi-standard rules for how to write Urdu sounds in the Latin alphabet (called Roman Urdu).\n\nIn your case though the name is in the Mohawk language whose writing system uses a variant of the English one. The colon in the writing is used to indicate a long vowel sound. You can read more about it on the [wikipedia page](_URL_0_).",
"Some linguist comes up with a transliteration scheme, and if other linguists and translators like it, it becomes a de facto standard. Sometimes academic organizations and governments pick one and make it official.\n\nThat's why words sometimes change (Peking - > Beijing) or are used inconsistently (Qaddafi, Khadafy, Gadhafi + about 100 more), the transliteration scheme changes or there is no single scheme everyone agrees upon."
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389q5p | why are all digital images rectangular? | In the past, [printing pictures on rectangular paper from a rectangular slide made sense, as do rectangular sensors in digital cameras producing rectangular photographs](_URL_0_), but digitally, why is the rectangle still our go-to? (Or is it?) Does the answer lie in history, photography, psychology, anthropology, technology?
One example would be being able to create online stickers without the need for a transparent background surrounding them in the shape of a rectangle. Why is there a box/rectangle around everything?
***
If what I'm getting at is still unclear, feel free to ask me for clarification in messages; I'll edit this post to make it more clear as needed. I tried looking this up everywhere, but it hasn't really been asked, perhaps because it's just been accepted as the norm? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/389q5p/eli5_why_are_all_digital_images_rectangular/ | {
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"In design, it's much simpler to lay things out on a spread when they are all rectangular. Normally designers lay things out using a grid insuring things are laid out with even spacing, odd shapes often make this task much more difficult. ",
"images on the computer are represented by a grid of dots because that's how monitors are made. You could make a vector image format (which uses lines and shapes instead of dots) that uses polar coordinates or something, but raster formats (the dots, which is pretty much the only way to represent photographs) are made up of a bunch of rows and it's easier to process if every row is the same size.",
"A lot of it is history. Photographs were all rectangular from the beginning. CRT technology for TVs and early computer screens were based on a rectangular grid of glowing phosphors. Over the years computers and display technologies advanced together to take advantage of this arrangement.\n\nNext it is much more efficient in storage space and computing time to assume that all images are the same shape. With this assumption you don't need to store the location of each pixel with each pixel. You can provide a small amount of information up front (e.g. width and height) and then each pixel's location can be inferred based on its order in the file. If the image can be any shape you need to store the location of each pixel along with the pixel's color values. For a color image with a transparency channel that would be 50% more storage required (Red Green Blue Transparency X-coord Y-coord as opposed to just Red Green Blue and Trans) to store the same image data. Even more if you also allow pixels to be on top of each other (i.e. 3 dimensional coordinates). The data saved by not needing to store the empty pixels would not make up for this added storage for the coordinates. Also, most compression algorithms (see below) will shrink the amount of space necessary to store the transparent pixels in a rectangular image to almost nothing. Compression is really good at shrinking large areas of an image that are the same color.\n\nIt doesn't need to be rectangular necessarily to achieve this efficiency but given our display technology rectangles makes the most sense. You can't fill a rectangular screen completely without cutting off parts of the picture using any other shape. There are also design reasons why rectangles make the job of working with graphics on a screen easier (see other comments).\n\nFinally, one of the reasons that images and video work on the internet without our needing massive amounts of bandwidth is compression. These are algorithms that make image files smaller and still preserve its quality for display. One of the most important image compression algorithm, JPEG, depends on the fact that images are rectangular. It would have to essentially convert the image to a rectangle to compress it anyway."
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2789fm | how is the wii virtual console able to accurately emulate n64 games when the current state of n64 emulation is poor, at best? | Specifically, I tried playing *Kirby and the Crystal Shards* on several emulators, and none of them can emulate the game perfectly. The same goes for *Super Smash Bros.*, but both of these games work flawlessly on Virtual Console.
Is Nintendo actually taking the original source code for all these N64 games and rewriting them to work on the Wii's hardware? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2789fm/eli5_how_is_the_wii_virtual_console_able_to/ | {
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"I wouldn't call it poor. It is actually very good! My cell phone can handle every N64 game I've thrown at it almost perfectly. The only problem I have ever experienced is the occasional failed texture load.",
"Nintendo have all the original designs of the N64. They have the engineers who built it in the first place (presumably some of them still work there). They don't have to do the guesswork that people writing unofficial emulators do. \n\nMaybe \"guesswork\" is the wrong word, but writing an emulator without access to all the details of the hardware involves having to figure those details out for yourself, which is difficult, time consuming and hard to guarantee you are absolutely correct. Nintendo doesn't have that problem, they can refer to the original design documents."
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dkf6oy | why does a short circuit produce so much heat? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dkf6oy/eli5_why_does_a_short_circuit_produce_so_much_heat/ | {
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"A short circuit is a circuit with little to no resistance. No resistance means the maximum current can flow through the circuit. Maximum current = heat. This is how a circuit breaker works. There's a bar inside the breaker that will change shape based on heat. The more current, the more heat. Once the bar heats up enough from too much current, it moves enough to trip the breaker."
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2bbv3i | object oriented programming vs procedural vs functional | I have seen descriptions on this subreddit for OOP, but I would appreciate a comparison. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2bbv3i/eli5_object_oriented_programming_vs_procedural_vs/ | {
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"OOP and Procedural are sort of inside-outs of each other. Both are different ways of organizing data and the operations on that data, and the difference is where the operations are.\n\nIn Procedural programming, data structures are just things that hold data, and you have procedures (aka functions) that operate on them and create new data. So you might have a list data type that stores some things, and a \"join\" procedure that takes two lists and makes one list with all elements:\n\n val list1 = makeList(1, 2, 3); \n val list2 = makeList(4, 5, 6);\n val combined = joinLists(list1, list2); // 'combined' now contains [1, 2, 3, 4, 5, 6]\n\nIn OOP, the operations on the data are contained within the data structures themselves, and called methods. So you end up with something like:\n\n val list1 = new List(1, 2, 3);\n val list2 = new List(4, 5, 6);\n list1.addAll(list2); // 'list1' now contains [1, 2, 3, 4, 5, 6]\n\nFunctional programming is a paradigm that seeks to eliminate mutation, which has a lot of benefits in many situations. It is the opposite of Imperative programming, which is what the vast majority of common languages use (including C, C++, Java, and Python). Many of these languages have some ability to restrict mutation (e.g. the const or final keywords), but aren't purely functional and don't get very many of the benefits. FP languages can be object-oriented or procedural.",
"_Procedural_ code is like a recipe. Do this, then do that, repeat it 5 times, and so on. This is really just a model of how a single CPU (or \"core\") actually works, at a fairly low level.\n\n_OOP_ is a bit of a gimmick, in my opinion. It surprises me that younger programmers still ask about it. But, to give an overview, I would say that it consists mostly of taking the nouns of your problem and making them into data types, complete with associated operations. You might make a \"point\" or \"imaginary number\" data type, and then define its operations, along with the nature of its internal (private) representation. Then, if the operations you defined are shared in common with other data types, code that was written without any consideration of your new type can be made to operate with it. If you defined a comparison operation, for example, sort algorithms written by others will still work on your new data type. That's \"polymorphism\".\n\n_Functional_ code consists purely of function calls, and function definitions (which are themselves built of function calls). It doesn't have variables (only parameters going into and out of functions). The good thing about functions is that they're entirely self-contained. You pass some bytes in, get some bytes back, and nothing else is affected. There are no \"side effects\", like difficult-to-track changes to global variables or private object state, to worry about. This makes functional programming appealing in a multi-thread environment (where multiple copies of your code are running at the same time). There's less chance for one thread to step on another's metaphorical toes, since each operation is self-contained. If a thread calls a function, that function has its parameters, and they have absolutely nothing to do with (for example) some other call to the function made from another thread. \n\nSo, the \"functional\" programmer is sacrificing handy things like being able to assign values into variables in exchange for some thread-safety (and, in general, for more provable correctness.) Of course, this breaks down a bit in practice. I/O is basically one gigantic \"side effect\", for example, and you damned sure do have to synchronize your I/O regardless of whether you wrote \"functional\" code or not."
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4hiaaa | how efficient is our digestive system? | For example, if we consume 100 calories we are definitely not going to suck up all the 100 calories through our digestive system. What is the average efficiency of a human digestive system?
If a thin person eats too much and does not gain weight does this mean his digestive system's efficiency to consume calories is very low? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4hiaaa/eli5how_efficient_is_our_digestive_system/ | {
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"There's no single answer as our digestive efficiency is GREATLY affected by a bunch of different things, so there's no \"number\". The only really consistent measure is that there are about 3500 calories in a pound of body fat.\n\nDigestive systems are affected by how often we eat and how much quantity we consume at a single sitting, what the caloric density (how many calories per unit of its weight) of the food we eat is, how much water it contains or that we consume with it, how compatible it is with the microbes in our guts, how well it's chewed, what our fitness level is, and what our activity level is. And a HUGE calorie thief is the amount of energy your body consumes to drive its own digestive processes - white bread almost none, whole grain stuff a lot more.\n\nAll that aside, our digestive systems aren't very efficient at extracting every calorie at all, again depending on the type of food those calories are in. Honey, for example, we get almost every calorie from; raw kale in a salad, not nearly so much. But a skinny teen and an obese one living for a week on the same diet of pizza and beer will probably result in different weight gains at the end of that week, and having the obese person's digestive system be better at converting that beer and pizza to stored fat is going to contribute to it.\n\n(As proof that our bodies are inefficient, even though it's gross to mention, you can burn dry poop, and flies and dung beetles can grow their young in it.) ",
"It really depends on what you're eating and how you want to define the calories in the food - all of the possible calories, or just what humans can use? In general, it costs about 10% of the available calories to process the other 90% you get - digestion takes energy, eh?\n\nBigger molecules like complex sugars (such as cellulose) are all but unusable by us. It takes more time and energy for us to break them into the single chain sugars like glucose that we actually use. Some smaller chains can get broken, though. Still, some of our gut bacteria use the bigger chains, and we do utilize the big chains as fiber to hold our stool together into solid pieces. So it gets used, kind of, but not for energy. \n\nAs well, a lot of the protein we ingest isn't broken down into energy, but used as that protein. This is especially true of proteins we can't make but still need, like ~~vitamin C~~ myosin, one of the proteins that makes up muscle fibre [thanks u/nem3sys]. So while those calories are available, they're not used as such. Still other proteins aren't worth the energy it takes to get the energy out, particularly if you're already eating a healthy diet (wheat gluten is like that - most of it gets passed because you can't use it as protein and it's not worth the energy).\n\nSo it really comes down to what you're eating, how active you are, what your usual diet is like, etc. You're not going to use a lot of, say, that salad you're eating, probably, but you're also not going to turn a lot of that steak into energy, either. Just about the only food that gets used completely is sugar, because it's already in the form it needs to be for your body to use the energy.\n\nFor an example of calories we can't use: cotton is basically just cellulose chains. You can burn it, it clearly contains energy. Cows can eat it and use that energy - it's digestible to some creatures. But a human could eat cotton all day long and the only thing you'll get out of it is constipated.\n\nEDIT: A note on proteins. u/nem3sys brought up myosin, I followed his cue on that. In any case, as u/TooLittleToLatte and u/kittenwhisker have pointed out protein is broken down into its constituent amino acids by digestion regardless of its ultimate use. My point was to specify that protein can either be broken down and used to gain energy, *or* the amino acids can be rebuilt into the proteins our body needs, but not both. In some cases, like vitamin C, we can't make them so we have to use it for building proteins or regulating bodily functions. Wheat gluten, on the other hand, is digestible, but we don't need most of its constituent pieces so they are converted into energy, *if* our bodies bother with it. How much protein you convert into energy, how much you save as amino acids, and how much you excrete unused depends what kind of protein it is and on the other parts of your diet, including what else you're eating along with your source of protein.\n\nEDIT^2: More corrections. Turns out I bit off more than I could chew (pun) with this ELI5. I welcome any corrections to the bits I've misunderstood or miscommunicated. Anyone who knows the technicalities of the biology, please be patient with me, I'm doing my best!\n\n[the_original_Retro's answer](_URL_0_) is great and deserves upvotes, as do the comments offering corrections to the bits I've messed up!",
"There was a similar question to this recently in /r/fitness IIRC in regards to exactly what a calorie was. Someone had provided this link so I'm basically just propagating the information they listed but it does go over some general information on digestion in regards to caloric intake.\n\nI'm not sure if this is allowed in ELI5 (my first post here) but it seemed to explain it to me in a very informative and simplistic way, so hopefully it helps as well.\n\n_URL_0_",
"Scishow just had a video about a similar topic: _URL_0_",
"I've never been able to find any good studies on this, but I think small differences could make huge differences. Imagine two people who each consume 2000 calories per day. One extracts 95% of the energy, and the other 94%. That's a 20 calorie per day difference, which at approximately 3500 calories per pound, is just over 2 pounds per year. That obviously adds up over the years.",
"Is poop a viable source of nourishment?",
"Just to preface, I have a BS in nutrition and dietetics but I am not a registered dietitian and I do not work in the field.\n\nWhen considering human evolution, biochemistry, and metabolism, it is important to remember that we adapted in ways that help us survive. Efficiency is paramount. In terms of calories alone, we will absorb nearly all of the 100 calories from your example. How many exactly? it's too hard to say. Differences in gastric transit time, enzymatic action (both in numbers and speed), total villi surface area, hydration status and more can change the result. Remember, bodies are made to be efficient. The variance between individual will be so negligibly small.\n\nThe latter part of your question actually has less to do with metabolism and more to do with psychology. Metabolism independent of height/weight/muscle mass/fat mass can vary by +/-200kcal. The notion that 100lb Timmy can devour 4 large pizzas a day and not gain a pound is a lie. A BMR like this deviates so far from the mean that it would be impossible to survive outside of modern civilization. Remember, we evolved to survive efficiently. It would not make any sense for person A to need 4000kcal while person B needs 2000kcal just to exist per day. 100lb Timmy is almost always very guilty of misreporting ingested calories- this is a problem in nutrition research. Skinny people are notorious for over-reporting calories and overweight people are notorious for under-reporting calories. This has been proven multiple times through research to identify said confounding variables. The only method of testing for this that I recall uses a mask to measure gas exchange (net exchange of CO2 can be correlated to calories burned). Subjects are kept inert, in a bed, all meals are calorie counted by researchers and then the mask is left on to measure total calories burned. As far as I know, no anomalous 100lb Timmy exists."
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2u7rgj | what is a computer "doing" when it's slow? | For example, I work on a Windows machine that's starting to get slow because it's a few years old. When I open a document, or try to open a new tab on my browser, or move an object in my PowerPoint (or anything, really), it just sits there doing nothing for like a minute, then it does the thing.
What is it doing as it sits there? And why does it suddenly do it a minute later? Is it "thinking" about how to do it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2u7rgj/eli5_what_is_a_computer_doing_when_its_slow/ | {
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"It has a bit to do with how many things are running in the background. It's not thinking about how to do it, it's just doing a lot of things at once, especially if you have a ton of processes running. ",
"several times it just runs the virus checking...",
"It's not \"thinking\" about how to do it, it's actively trying to get there.\n\nA Windows computer that is a few years old and not taken care of properly will be bogged down by junk processes running in the background, temporary files, registry errors, and even malware that all added up make things like opening a simple PowerPoint which used to happen instantly - pretty slow.",
"The reason your computer slows down is because certain tasks are 'blocking' meaning a program cannot continue until certain conditions are met. One of the most common blocking actions is getting data from a hard drive. The only things a program can do while waiting for input is to check to see if there is any input (by checking a memory location over and over) or letting other programs run for a while and then checking if there is any input. When the program is the operating system there's nothing else to run because you're expected to finish whatever you're doing before returning: so you just have to sit and spin checking that memory location.\n\nOne of the things an operating system is supposed to handle is memory. A program knows about \"virtual memory\" locations, but where that memory is physically is handled by the OS. It is common to have a 'swap file' on the hard drive where the memory of sleeping programs is stored temporarily in order to keep all your physical memory available for the current program to use.\n\nAs your hard drive fills and files get placed non-optimally all over the platter it takes longer and longer to physically move the read head back and forth to find files and directories. \n\nSeveral things contribute to relying on more and more disk access as your machine gets older. More icons on your desktop, more background processes being loaded \"to make loading faster\" for specific programs you've installed (this is actually a thing!), more files being checked for changes, more indexes being kept to make searches faster, and so on.\n\ntldr: The reason your machine is getting slower is because it's doing more things in the background that require blocking tasks."
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6ql5i7 | what is the actual difference between the three fuel grades found at gas stations? i understand many cars use premium fuel but i don't know exactly why. also why unleaded plus is there a situation where regular or premium are not suitable (besides price of course) -thanks | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6ql5i7/eli5_what_is_the_actual_difference_between_the/ | {
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"This has been asked about a thousand times, so for a more complete answer you should search.\n\nShort version: Higher octane rating means higher knock resistance. High compression engines need higher octane rated gas to avoid knocking, which can damage the engine and reduces fuel economy. Using plus or premium gas in an engine that doesn't need it does nothing but waste your money."
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6wvgdm | what is the turnaround time when it comes to donating to a disaster relief program? what's the process from donation, to actually being received by those affected? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6wvgdm/eli5_what_is_the_turnaround_time_when_it_comes_to/ | {
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"I am not sure about how long it takes for the money to flow in but I did some work for the Red Cross many years ago and they used 3 sources to fund rapid response. The have some money in the bank, they have banks that will lend them for short term and the buy on credit. Large outfits like that have a lot of experience and can estimate donations and they spend counting on those results.",
"Donations are rarely 'received' by those affected.\n\nWhat happens is that organizations like the Red Cross have an existing infrastructure and staff for dealing with disasters, and that's what they use for the response.\n\nSo your donations are really being used to keep the lights on until the *next* disaster.",
"Here is an article that talks about hat happened with money from other disasters vis a vis the Red Cross.\n\n_URL_0_"
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bwa8ez | why does it "feel good" to look at someone that cute? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bwa8ez/eli5_why_does_it_feel_good_to_look_at_someone/ | {
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"When looking at something or in your case someone attractive, your body releases some happy hormones which make you feel good. This is because of the fact that our bodies are biologically always in search for a mating partner and the 50 year man is most likely not a prefferable mating partner for you.",
"Lust is driven by the desire for sexual gratification. The evolutionary basis for this stems from our need to reproduce, a need shared among all living things. Through reproduction, organisms pass on their genes, and thus contribute to the perpetuation of their species.\n\nThe hypothalamus of the brain plays a big role in this, stimulating the production of the sex hormones testosterone and estrogen from the testes and ovaries. While these chemicals are often stereotyped as being “male” and “female,” respectively, both play a role in men and women. As it turns out, testosterone increases libido in just about everyone. The effects are less pronounced with estrogen, but some women report being more sexually motivated around the time they ovulate, when estrogen levels are highest.\n\nMeanwhile, attraction seems to be a distinct, though closely related, phenomenon. While we can certainly lust for someone we are attracted to, and vice versa, one can happen without the other. Attraction involves the brain pathways that control “reward” behavior, which partly explains why the first few weeks or months of a relationship can be so exhilarating and even all-consuming.\n\nDopamine, produced by the hypothalamus, is a particularly well-publicized player in the brain’s reward pathway – it’s released when we do things that feel good to us. In this case, these things include spending time with loved ones and having sex. High levels of dopamine and a related hormone, norepinephrine, are released during attraction. These chemicals make us giddy, energetic, and euphoric, even leading to decreased appetite and insomnia – which means you actually can be so “in love” that you can’t eat and can’t sleep. In fact, norepinephrine, also known as noradrenalin, may sound familiar because it plays a large role in the fight or flight response, which kicks into high gear when we’re stressed and keeps us alert. Brain scans of people in love have actually shown that the primary “reward” centers of the brain fire like crazy when people are shown a photo of someone they are intensely attracted to, compared to when they are shown someone they feel neutral towards (like an old high school acquaintance).\n\nFinally, attraction seems to lead to a reduction in serotonin, a hormone that’s known to be involved in appetite and mood. Interestingly, people who suffer from obsessive-compulsive disorder also have low levels of serotonin, leading scientists to speculate that this is what underlies the overpowering infatuation that characterizes the beginning stages of love."
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f13z6x | why can dry skin result in more growth of ingrown hairs? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/f13z6x/eli5_why_can_dry_skin_result_in_more_growth_of/ | {
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"Because the skin isn't so flexible to allow the hair to push through. You should also be exfoliating as well as moisturizing to help prevent ingrown hairs."
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frmf91 | why computer games often have bugs connected to the amount of fps (frames per second)? in some games, it affects the movement speed of playable character. red dead redemption 2 had the problem with it too: if you have many fps, it made character's weight lose. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/frmf91/eli5_why_computer_games_often_have_bugs_connected/ | {
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"More of a side comment than an answer, but the original Call of Duty game had an FPS related bug on multiplayer servers. The host could limit the max FPS to a certain amount, and it would effect the gravity of your server. You could moon jump, or even float away into the air. Never did figure out how that one worked, but to this day it's my favorite bug of all time.",
"Game processes that happen over time usually run on what is usually called \"ticks\". A tick is usually a fixed amount of time, and different mechanics of the game are calculated once ever x ticks. For example, physics calculations such as ~~clipping~~ collision detection (checking wether or not two objects touch) usually happen every single tick. Console games designed to run at a fixed frame rate also often have frame rate and tick speed tied to one another. For example, a game running at 30 frames per second might also use 30 ticks per second. A good example for that is the N64 game Goldeneye, where looking down to make the game run at higher fps also makes James Bond run faster. \n\nSo while I'm not familiar with the RDR2 bug you're describing, what might happen here is that the process of losing weight is tied to the game's tick speed, and that the tick speed in turn is tied to the fps rather than running on an entirely separate counter.",
"It's easier to program a game if everything is in sync - and the easiest thing to sync to is the rendered frames.\n\nHistorically one thing that was often linked to the FPS was the physics and collision engine. An example of a typical game compute loop:\n\n1. Calculate physics\n2. Calculate collisions\n3. Render frame\n\nIf your FPS is very low, then funky things can happen with the physics and collision. \n\nFor example: The physics engine uses the velocity & acceleration of every object to work out the objects position once a frame. Then the collision engine establishes if objects are overlapping, and adjusts their position such that they aren't overlapping. This stops things passing through each other. However a fast moving object may be able to pass through another because between frames, it moved far enough that it completely pass through another one before the collision detection picked this up.\n\nA well programmed game won't work like this, the physics and FPS will happen at different rates. The physics (if important to the game) should be run at a much higher rate than FPS - however if your computer is slow (i.e low FPS), then the physics engine may also be ran fewer times per second, so similar effects can happen.\n\nAnother problem you get is we are approximating continuous physics in discrete steps. When things are moving in complex paths, if the time step gets too large strange issues can occur. For example two objects joined together by a flexible joint. Often the physics engine resolves all the forces on both objects, and then works out their speed, acceleration and finally position. This often has a small error at the end, for example the objects end up 0.001m further apart than they should be, the physics engine applies an extra force to bring the objects back together on the next iteration. If the FPS is low, and the computer is struggling, the physics will get computed less often, and that small position error may become large. The extra forces applied to bring everything back together can get wild and things go crazy. The developer may do things like scale forces & mass relative to the calculation frequency to stabalize things during blips in calculation speed, and this can cause big issues if the blip lasts too long."
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19hmpl | how do electricity companies store electricity? | Is it stored up or does it just generate as we use it? How do they store electricity that isn't currently in use? What's going on there? This is just something I've never understood or really looked into, but I've always wondered. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/19hmpl/eli5_how_do_electricity_companies_store/ | {
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"they calibrate production to match consumption. sometimes they get it wrong and get brownouts. they dont store it though as far as i know.",
"First: They don't. It's pretty difficult to store energy in any form, and electricity has the very nice property of being phenomenally easy to move around (by just tying a bunch of wires together), so they don't store it, and they don't need to. They just generate it on demand. \n\nSecond: The electricity system is called a 'grid.' There are three entities involved in the grid: The customer, usually a \"retail electric provider\" - someone who sells electricity to an end user like a homeowner or a factory. The generator, ie the power plant, the guys who produce electricity. And finally, the Grid Operator (in the US they are called System Operators), ie the person who controls the cables that connect the generators to the customers. \n\nThe Grid Operator is responsible for controlling how much power there is on the grid at any given point in time. They are the \"Air Traffic Controllers\" for the electric grid. They sit in a big room full of computers, and monitor how much electricity is where in the grid. They plan, in advance, how much electricity will be needed and when. They create this plan based on current and past usage; then they will issue orders to the generators/power plants, telling them what they must produce, and when. \n\nThe grid operator monitors the amount of power in the grid at any given point in time. As they are monitoring, people are plugging things in and turning them off (the amount of power people are using is called \"load\"); meanwhile power plants are spinning up (adding electricity) and spinning down. This constant variance between the load and the supply has to be monitored, because in order for the grid to 'stay up' - ie, continually provide power, it has to maintain within a certain range, usually determined by voltage. \n\nYou can thing of the grid as a river that ships are using to navigate. If the water level gets too high, it destroys the things near the river (The machines that people plug into the wall that use electricity). If the water level (electricity level) gets too low, then ships can't get through and the entire grid will shut down. The grid operator monitors that and takes action. In emergencies, if the load is just too large or supply isn't enough, they will actually *disconnect* people (called a planned outage, or brownout) - usually residential customers - to make sure that power isn't lost everyone (especially at places like hospitals). \n\nHope this helps. ",
"They don't store electricity, per se. They are always generating EXACTLY as much power as is required at that moment.\n\nThe electric grid is constantly changing, as demand for electricity goes up and down. Demand tends to be low during the night, and high during the day.\n\nAll over the grid, power plants are producing power. Some of them are running at 100% all the time. These are called \"baseload\" power plants. Some of them are running at less than 100%, or even not running at all!\n\nBecause not all of these power plants are running at 100%, they have the ability to produce more than what they're doing at the moment. Let's say you have a coal-fired power plant that is running at 80% capacity. Then, as temperature get hotter, more people turn on their air-conditioning units and the demand for electricity goes up. When demand goes up, this coal-fired power plant increases its output to meet the new (higher) demand.\n\nSo we have all of these power plants, some of them running at less than their maximum capacity. The difference between their maximum capacity and their current output is called \"spinning reserve\", that is power that can be called upon very quickly (because the plant is already up and running) in case demand goes up. The electric grid is required to maintain a certain amount of spinning reserve in case there is a sudden change in demand, or if some other power plant trips offline.\n\nIf the demand goes up too high, and all of the power plants are running at 100% capacity, that's dangerous. If somebody turns on their air-conditioner, it could exceed their capacity and you get a brownout. To prevent this, they can call on other power plants, that aren't running at all (idle) and tell them to get fired up and ready to go...just in case they're needed.\n\nSo they don't store electricity...they just maintain power plants that are available to create electricity as it's needed.\n\nEDIT: typos",
"While most don't store any, some do. They pump water up an incline or dam and when they need electricity, they let it flow back down turning turbines.\n\nThe efficiency isn't too bad this way and it's a pretty good way to store energy without the need for batteries/capacitors, etc."
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75yjrv | how does the wood type that an instrument is made out of impact sound quality? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/75yjrv/eli5_how_does_the_wood_type_that_an_instrument_is/ | {
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"Like copper and iron are both metals but have *drastically* different properties, oak and pine are both woods but have drastically different properties.\n\nProperties that differ could be anything from ease of working with the material to the resonant frequencies of the wood to how well it holds up with time or maintains its acoustic properties."
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5ibxv7 | why does sodium chloride dissolves in water but not in ethanol, when both are polar compounds? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ibxv7/eli5_why_does_sodium_chloride_dissolves_in_water/ | {
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"NaCl does dissolve in ethanol, just not very much. Water is far more polar and and the small molecular size would allow for more interactions with Na+ and Cl-. With more ions being supported by the solvent, more ions can be accepted/dissolved in the sovlent, and so salt has a higher solubility in water than ethanol. ",
"Alcohol and water are great solvents\n\nThink like dissolves like, EtOH being an organic compound, it works better with organics.\n\nIn pharmacy, we do a lot of compounding with EtOH because it works great with medicines (organics).\n"
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nl7yz | how did kim il-sung get into power, and how was he able to convince his people that he had superpowers? | Please guys don't just say under threat of violence. I'm genuinely curious how him and his son were able to have such a way over these people - and how they got there in the first place. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/nl7yz/how_did_kim_ilsung_get_into_power_and_how_was_he/ | {
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"When you have near total information shut down, when the people just don't know any better, it's easier to convince them of crazy stuff.",
"It's definitely not \"like you're five\", but this is a really good overview of North Korea - how it got there, how it's run, and what the potential impact of Kim Jong Il dying is (it was written in 2006).\n\n_URL_0_\n",
"In very simplified terms. \n\nKorea was under Japanese rule from 1910-1945. Prior to that it was ruled by various Korean imperial dynasties. After 1945 the Japanese withdrew (a consequence of their defeat in WWII was that they lost their empire) \n\nAt this time the cold war was just getting going and a united nations agreement was produced whereby Korea would be divided along the '38th parallel' (this remains the border between North and South today) with the North being administered by the soviet union and the south by the united states. \n\nThe soviets established a civil administration in the North, designed to ensure loyalty to the USSR by 1948 the party apparatus of modern North Korea was established and Kim Il Sung was in power. The North Korean success in the Korean war _URL_2_ then provided an excellent opportunity for the leaders of North Korea to build and cement a national mythology around nationalism, their ideology and their cult of personality. \n\nHis continuing high status within North Korea today can be accounted for by two main factors. \n\nThe traditional respect accorded to authority figures and ancestors, once the emperor, now the 'dear and great leaders' which stems from _URL_1_ \n\nand\n\nThe effectiveness of state propaganda, learnt from Stalinist USSR and the ruthless crushing of dissent. (all the 1984 stuff)\n\nI think it is far more illustrative to view the current regime in terms of the wider history and culture of Korea and its corruption of that, rather than simply as being a copy-cat Stalinist regime. After all, we need to explain why the North Korean government has survived the fall of the USSR. \n\nEDIT: Corrected on border, it has shifted in parts since 1950s'. Also found this article _URL_0_ by the late Christopher Hitchens which argues that the racist nationalism is more significant than either communism or Confucianism in NK. \n\n\n\n",
"I don't think North Koreans actually believe any of that. At least not most of them. Most of the interviews with people who escaped the North paint the average N.Korean as being completely level-headed and grounded in reality.\n\nBeing how we always hear North Korean propaganda, and opinions from the people themselves hardly ever escape the borders, it's probably just us going \"Hahahahaha, he thinks he's a God?! I can't believe North Koreans believe this!\"",
"Control of information and propaganda is how they've stayed in power this long. NK puts a lot of effort into making it an issue of pride for its people by constantly lying to them and telling them \"they're the best in the world\" and that \"nobody has anything better than them\". Sound familiar? Combine it with a cocktail of punishments for those who dare to say otherwise and you get a people too afraid and too ignorant to change things.\n\n\"Beware of he who would deny you access to information, for in his heart he dreams himself your master.\"",
"During WW2 he was a famed resistance fighter, he did some very heroic deeds against the Japanese who were at that point in control of Korea. When Japan fell, he was one of several noteworthy Koreans that the USSR brought together to rule Korea (the USA simultaneously doing the same with South Korea). Through political wrangling and the odd execution of his rivals (often done by Stalin, who had been informed that Sung was the best candidate to be his supporter in Korea), he swiftly became Prime Minister.\n\nAs for convincing his people that he had superpowers, you have to put this down to the misinformation that North Koreans have eternally been fed. For a couple of decades, North Korea was genuinely one of the richer countries on the planet, and was often held up as an example of communism working. As their allies dropped away, they were left further and further isolated from the rest of the world. Kim Il-Sung would have statues everywhere, the people would be told of world leaders consulting him for advice, and that he was endlessly outthinking the incredibly rich and powerful Western aggressors who were attempting to destroy NK. Give it 50 years of that sort of revelry and you'd believe anything about someone. \n\nThe whole 'Kim jong-il/il-sung says that he has superpowers!' sort of thing, unfortunately, is mostly made up by the West though. Certainly, both dictators led people to believe that they were at least demi-god in their nature (almost all accounts of North Koreans upon hearing of Sung's death in 1994 express surprise and shock that Sung could ever die- it just seemed something impossible that he could), but as for convincing people that they actually have superpowers- this isn't really believed in North Korea, or even told to ordinary North Koreans. They see their dictators as perfectly benevolent, heroes of their political ideals, and would do anything (and do everything) to help their country). Anything that we hear such as 'Kim Il-Sung could control the weather' etc. is more likely coming from their devotion to him spilling over into the irrational, rather than there being a press release that he can indeed control the weather.\n\nedit: this is quite badly written, my bad.",
"In order to live in Pyongyang and receive the benefits of party-favored citizenship--better jobs, education, access to goods and services--you must be a devout supporter of the Kim family. You must publicly display your loyalty in song and tears, take part in pageants, and more.",
"In order to advance in North Korean society- and sometimes to avoid suspicion and persecution- one must prove themselves dogmatically fanatic. This leads many otherwise rational North Koreans to attempt to outdo each other in devotion to the party and the dictator. Thus, exaggerating emotions about events like the dictator's death, and stretching faith in his abilities to that of the supernatural.",
"Evil President's across the world make use of propaganda team which will tell the people using mass media(TV,Newspapers) on what they want to achieve. \n\nFor ex: If you want to invade another country in a remote location who has got nothing to do with you, then you use propaganda and convince your people how bad that country is to your future, the hidden agenda could be defense industry lobby to make sure there is continuous purchase made by your government. \nAlways keep the country at higher threat level, so soon people will get paranoid and believe everything you say. \nSlowly curb the basic human rights like freedom of speech, peaceful protest,etc",
"Because when people are closed off from the world, very hungry and threatened with death, you can make them believe all kinds of silly stuff.",
"My favorite Kim-ism's are:\n\n- Had down blankets made from the chins of 10,000 sparrows.\n\n- Stated that he was an expert at the internet\n\n- Told the Korean people that the red cross shipment were western offerings of appeasement to him.\n\nHow North Korea became just like \"1984\" is mostly speculated as during this time there was a media blackout and it was the most xenophobic state in history. \n\nIt's kind like asking, \"What do we know about mass propaganda at the level of North Korea?\" \n\nMarxist communism had grown to cult status at that time and a few Charles Manson type leaders (Mao, Pol pot and Kim) had become little fascists. \n\nFor a really good **TL:DR** check out Christopher hitchens on North Korea. ",
"So you are telling me that he didnt died fighting Lex Luthor!?\n",
"He beat everybody in starcraft.\n",
"With golf skills like his, it probably wasn't that hard. ",
"Philosophy is the driver of history.\n\nThere are two philosophies about how we should behave towards others.\n\n1. **Doctrine of duties**: This one says, we have unchosen obligations towards others.\n2. **Doctrine of rights**: This one says, we have chosen obligations towards others.\n\nBoth of these are mutually incompatible. While we can pretend to have both, but we cannot do so for long. Either we stick with unchosen obligations or we go for chosen obligations.\n\nThe only way **Doctrine 1** can be implemented is by denying everyone the inalienable freedom to live for one's own sake, act for one's own sake and pursue one's own goals.\n\nThe only way **Doctrine 2** can be implemented is by protecting everyone's inalienable freedom to live for one's own sake, act for one's own sake and pursue one's own goals.\n\nNorth Korea implements **Doctrine 1**. So its government *has* to use methods to coerce people against their own interests. You are right in saying that not everybody can be made to give up their rational faculty by the threat of violence. In fact religions realized this long back. Religions and North Korean government, hijack on certain \"flaws\" of the mind like the need to live upto principles, the innocent openness to possibility of phenomena yet unexplored etc to convince them of their leaders supernatural nature, so as to solidify their submission to the will of the government, which in turn *ought* to use this submission to implement **Doctrine 1**.",
"Nice try, Kim Jong-Un.",
"The Korean peninsula had been either engulfed in war or under occupation since the 1890's. This is due to its geographical significance. It is often called the \"dagger at the heart of Japan\" for obvious reasons and also has value to Russia because it provides year round warm water access to the Pacific. The Sino-Japanese War of 1894-1895 and the Russo-Japanese War of 1904-1905 were fought largely for these reasons. Basically China, Russia, and Japan quarreled over Korea for a few decades because of the peninsula's strategic geography. Japan won these wars but as the 20th century progressed Korea remained in flux as China, Japan, the USSR, and the USA all sought influence over the peninsula at one point or another.\n\nAll this outside pressure was a shock to Korea, which prior to 1890 was a very isolated place often called the \"Hermit Kingdom.\" As intangible-tangerine has explained, when WWII ended the USSR and USA divided influence over Korea. The northern/communist faction ended up having strong military success over the anti-communist south and the US which withdrew in 1949.\n\nBecause of this history of outside rule and influence, Kim Il-Sung came to power as a \"father of the nation\" type figure. He was the first indigenous ruler of Korea after about 75 years of occupation and war. \n\nSurely Confucian religious traditions played a role in the development of the cult of personality surrounding Kim but his rise to superhuman status is hardly unique. Other countries that have gained independence after long periods of foreign meddling have also come to seeing their national fathers as pseudo-godlike figures. Some examples would be India/Ghandi, Cuba/Castro, USSR/Stalin, France/Napoleon, and the US/the Founding Fathers. \n\n\n ",
"When you have near total information shut down, when the people just don't know any better, it's easier to convince them of crazy stuff.",
"It's definitely not \"like you're five\", but this is a really good overview of North Korea - how it got there, how it's run, and what the potential impact of Kim Jong Il dying is (it was written in 2006).\n\n_URL_0_\n",
"In very simplified terms. \n\nKorea was under Japanese rule from 1910-1945. Prior to that it was ruled by various Korean imperial dynasties. After 1945 the Japanese withdrew (a consequence of their defeat in WWII was that they lost their empire) \n\nAt this time the cold war was just getting going and a united nations agreement was produced whereby Korea would be divided along the '38th parallel' (this remains the border between North and South today) with the North being administered by the soviet union and the south by the united states. \n\nThe soviets established a civil administration in the North, designed to ensure loyalty to the USSR by 1948 the party apparatus of modern North Korea was established and Kim Il Sung was in power. The North Korean success in the Korean war _URL_2_ then provided an excellent opportunity for the leaders of North Korea to build and cement a national mythology around nationalism, their ideology and their cult of personality. \n\nHis continuing high status within North Korea today can be accounted for by two main factors. \n\nThe traditional respect accorded to authority figures and ancestors, once the emperor, now the 'dear and great leaders' which stems from _URL_1_ \n\nand\n\nThe effectiveness of state propaganda, learnt from Stalinist USSR and the ruthless crushing of dissent. (all the 1984 stuff)\n\nI think it is far more illustrative to view the current regime in terms of the wider history and culture of Korea and its corruption of that, rather than simply as being a copy-cat Stalinist regime. After all, we need to explain why the North Korean government has survived the fall of the USSR. \n\nEDIT: Corrected on border, it has shifted in parts since 1950s'. Also found this article _URL_0_ by the late Christopher Hitchens which argues that the racist nationalism is more significant than either communism or Confucianism in NK. \n\n\n\n",
"I don't think North Koreans actually believe any of that. At least not most of them. Most of the interviews with people who escaped the North paint the average N.Korean as being completely level-headed and grounded in reality.\n\nBeing how we always hear North Korean propaganda, and opinions from the people themselves hardly ever escape the borders, it's probably just us going \"Hahahahaha, he thinks he's a God?! I can't believe North Koreans believe this!\"",
"Control of information and propaganda is how they've stayed in power this long. NK puts a lot of effort into making it an issue of pride for its people by constantly lying to them and telling them \"they're the best in the world\" and that \"nobody has anything better than them\". Sound familiar? Combine it with a cocktail of punishments for those who dare to say otherwise and you get a people too afraid and too ignorant to change things.\n\n\"Beware of he who would deny you access to information, for in his heart he dreams himself your master.\"",
"During WW2 he was a famed resistance fighter, he did some very heroic deeds against the Japanese who were at that point in control of Korea. When Japan fell, he was one of several noteworthy Koreans that the USSR brought together to rule Korea (the USA simultaneously doing the same with South Korea). Through political wrangling and the odd execution of his rivals (often done by Stalin, who had been informed that Sung was the best candidate to be his supporter in Korea), he swiftly became Prime Minister.\n\nAs for convincing his people that he had superpowers, you have to put this down to the misinformation that North Koreans have eternally been fed. For a couple of decades, North Korea was genuinely one of the richer countries on the planet, and was often held up as an example of communism working. As their allies dropped away, they were left further and further isolated from the rest of the world. Kim Il-Sung would have statues everywhere, the people would be told of world leaders consulting him for advice, and that he was endlessly outthinking the incredibly rich and powerful Western aggressors who were attempting to destroy NK. Give it 50 years of that sort of revelry and you'd believe anything about someone. \n\nThe whole 'Kim jong-il/il-sung says that he has superpowers!' sort of thing, unfortunately, is mostly made up by the West though. Certainly, both dictators led people to believe that they were at least demi-god in their nature (almost all accounts of North Koreans upon hearing of Sung's death in 1994 express surprise and shock that Sung could ever die- it just seemed something impossible that he could), but as for convincing people that they actually have superpowers- this isn't really believed in North Korea, or even told to ordinary North Koreans. They see their dictators as perfectly benevolent, heroes of their political ideals, and would do anything (and do everything) to help their country). Anything that we hear such as 'Kim Il-Sung could control the weather' etc. is more likely coming from their devotion to him spilling over into the irrational, rather than there being a press release that he can indeed control the weather.\n\nedit: this is quite badly written, my bad.",
"In order to live in Pyongyang and receive the benefits of party-favored citizenship--better jobs, education, access to goods and services--you must be a devout supporter of the Kim family. You must publicly display your loyalty in song and tears, take part in pageants, and more.",
"In order to advance in North Korean society- and sometimes to avoid suspicion and persecution- one must prove themselves dogmatically fanatic. This leads many otherwise rational North Koreans to attempt to outdo each other in devotion to the party and the dictator. Thus, exaggerating emotions about events like the dictator's death, and stretching faith in his abilities to that of the supernatural.",
"Evil President's across the world make use of propaganda team which will tell the people using mass media(TV,Newspapers) on what they want to achieve. \n\nFor ex: If you want to invade another country in a remote location who has got nothing to do with you, then you use propaganda and convince your people how bad that country is to your future, the hidden agenda could be defense industry lobby to make sure there is continuous purchase made by your government. \nAlways keep the country at higher threat level, so soon people will get paranoid and believe everything you say. \nSlowly curb the basic human rights like freedom of speech, peaceful protest,etc",
"Because when people are closed off from the world, very hungry and threatened with death, you can make them believe all kinds of silly stuff.",
"My favorite Kim-ism's are:\n\n- Had down blankets made from the chins of 10,000 sparrows.\n\n- Stated that he was an expert at the internet\n\n- Told the Korean people that the red cross shipment were western offerings of appeasement to him.\n\nHow North Korea became just like \"1984\" is mostly speculated as during this time there was a media blackout and it was the most xenophobic state in history. \n\nIt's kind like asking, \"What do we know about mass propaganda at the level of North Korea?\" \n\nMarxist communism had grown to cult status at that time and a few Charles Manson type leaders (Mao, Pol pot and Kim) had become little fascists. \n\nFor a really good **TL:DR** check out Christopher hitchens on North Korea. ",
"So you are telling me that he didnt died fighting Lex Luthor!?\n",
"He beat everybody in starcraft.\n",
"With golf skills like his, it probably wasn't that hard. ",
"Philosophy is the driver of history.\n\nThere are two philosophies about how we should behave towards others.\n\n1. **Doctrine of duties**: This one says, we have unchosen obligations towards others.\n2. **Doctrine of rights**: This one says, we have chosen obligations towards others.\n\nBoth of these are mutually incompatible. While we can pretend to have both, but we cannot do so for long. Either we stick with unchosen obligations or we go for chosen obligations.\n\nThe only way **Doctrine 1** can be implemented is by denying everyone the inalienable freedom to live for one's own sake, act for one's own sake and pursue one's own goals.\n\nThe only way **Doctrine 2** can be implemented is by protecting everyone's inalienable freedom to live for one's own sake, act for one's own sake and pursue one's own goals.\n\nNorth Korea implements **Doctrine 1**. So its government *has* to use methods to coerce people against their own interests. You are right in saying that not everybody can be made to give up their rational faculty by the threat of violence. In fact religions realized this long back. Religions and North Korean government, hijack on certain \"flaws\" of the mind like the need to live upto principles, the innocent openness to possibility of phenomena yet unexplored etc to convince them of their leaders supernatural nature, so as to solidify their submission to the will of the government, which in turn *ought* to use this submission to implement **Doctrine 1**.",
"Nice try, Kim Jong-Un.",
"The Korean peninsula had been either engulfed in war or under occupation since the 1890's. This is due to its geographical significance. It is often called the \"dagger at the heart of Japan\" for obvious reasons and also has value to Russia because it provides year round warm water access to the Pacific. The Sino-Japanese War of 1894-1895 and the Russo-Japanese War of 1904-1905 were fought largely for these reasons. Basically China, Russia, and Japan quarreled over Korea for a few decades because of the peninsula's strategic geography. Japan won these wars but as the 20th century progressed Korea remained in flux as China, Japan, the USSR, and the USA all sought influence over the peninsula at one point or another.\n\nAll this outside pressure was a shock to Korea, which prior to 1890 was a very isolated place often called the \"Hermit Kingdom.\" As intangible-tangerine has explained, when WWII ended the USSR and USA divided influence over Korea. The northern/communist faction ended up having strong military success over the anti-communist south and the US which withdrew in 1949.\n\nBecause of this history of outside rule and influence, Kim Il-Sung came to power as a \"father of the nation\" type figure. He was the first indigenous ruler of Korea after about 75 years of occupation and war. \n\nSurely Confucian religious traditions played a role in the development of the cult of personality surrounding Kim but his rise to superhuman status is hardly unique. Other countries that have gained independence after long periods of foreign meddling have also come to seeing their national fathers as pseudo-godlike figures. Some examples would be India/Ghandi, Cuba/Castro, USSR/Stalin, France/Napoleon, and the US/the Founding Fathers. \n\n\n "
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"http://www.slate.com/articles/news_and_politics/fighting_words/2010/02/a_nation_of_racist_dwarfs.single.html",
"http://en.wikipedia.org/wiki/Korean_Confucianism",
"http://en.wikipedia.org/wiki/Korean_War"
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"http://www.slate.com/articles/news_and_politics/fighting_words/2010/02/a_nation_of_racist_dwarfs.single.html",
"http://en.wikipedia.org/wiki/Korean_Confucianism",
"http://en.wikipedia.org/wiki/Korean_War"
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b47pfh | if the freezing point for hydrogen is -259.2°c, and the freezing point for oxygen is -218.8°c, why is the freezing point of water so much higher? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/b47pfh/eli5_if_the_freezing_point_for_hydrogen_is_2592c/ | {
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"Water is a polar molecule. The 'plus-side' of the molecule will attract the 'minus-side' of the molecule. This attraction means that it will condense and subsequently freeze at much higher temperatures than molecules of a similar size.",
"A couple things to think on:\n\n & #x200B;\n\n* A compound doesn't share the properties of its constituent parts. Sodium will kill you if ingested, chlorine will asphyxiate you if inhaled. Put them together and we pile a ton of it on our food and eat it without it exploding or asphyxiating us. It's not as reactive in that state.\n* A compound with stronger bonds will have a higher melting point. Example is salt (Sodium: 98C, Chlorine: -101C, Sodium Chloride: 801C.\n* Our measurement scales (Fahrenheit, Celcius) are arbitrary, and we base them on what happens to water (as opposed to Kelvin). There are only 273 degrees below the freezing point of water, but there are millions of degrees above the freezing point of water. If you look at temperature scales as a whole, a difference of 200 degrees isn't that much.",
"Hydrogen gas (H2) and oxygen gas (O2) have very weak interactions between molecules which are what are responsible for melting and boiling points. \n\nWater on the other hand has strong interaction between molecules which is why the melting and boiling points are significantly higher. \n\nAnd as someone else said, molecules don’t take on all properties of their constituent parts. "
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ca5loc | why does heat expand radius of the circle in metals? | Thermodynamic: In my understanding heat expands distance between metal particles in all direction. If we take cylinder (tube) and heat it up, shouldn't the hole of cylinder get smaller as heat increases, or does distance between air particles expand too? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ca5loc/eli5_why_does_heat_expand_radius_of_the_circle_in/ | {
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"Consider an iron tyre for an old-timey wheel. It's basically just a long strip of metal that's been bent into a hoop. If it weren't bent into a hoop and you heated it up, you would expect the strip to get longer. Since it is a loop, what that looks like is that the circumference gets bigger. (This is in fact what happens; it's fitted around the wheel while hot, and when it cools, it shrinks, squeezing the felloes onto the spokes and the spokes onto the hub.)\n\nNow let's consider the opposite case: a *huge* block of metal, practically infinite in size, with a narrow hole drilled through it. If you heat that up, the metal will tend to expand, but the metal near the drilled hole will have nowhere to go but inward, squeezing it shut.\n\nWhat we see here is that the expansion and contraction of materials due to temperature change has complex effects on the shape of objects. If you think about the second case, you can see how temperature changes can cause uneven changes in the internal stresses of a material, which is a serious engineering challenge."
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2do4hp | do pet fish get bored living in a fish tank? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2do4hp/eli5_do_pet_fish_get_bored_living_in_a_fish_tank/ | {
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"Found a study relating to this:\n\n_URL_0_\n > The first study to take a comprehensive look at fish aggression related to the size of the environment has revealed that most pet fish are probably really, really upset. The study found that cramped, boring conditions can make normally placid fish irritable, and sometimes aggressive to the point of attacking and killing their tankmates.\n > \n > The study, led by Ronald Oldfield with Case Western Reserve University was published in a recent edition of Journal of Applied Animal Welfare Science. In it, Oldfield looked at the Midas cichlid in three different environments. The first, the fish’s natural home in a Nicaraguan lake; the second, a cunningly crafted artificial stream in a zoo; and third, the much smaller tanks used by pet owners...",
"I'm a graduate student studying fish behavior.\n\nI feel pretty confident in saying that no, most fish don't get \"bored\" in fish tanks. I'd characterize boredom as an emotional state where an animal has insufficient stimulation in its environment, and often resorts to a series of repetitive behaviors which may be self-harming or involve pacing the walls or similar movements. Notably, these behaviors will often diminish when toys are provided. You _absolutely_ see this sort of boredom in animals like birds and mammals, but I personally have rarely seen it in fish or amphibians. I've definitely seen evidence of it in some, but not all reptiles. Most fish lead more behaviorally constrained lives--they don't generally have as great a drive to investigate and interact with objects or areas in their environment, and thus don't seem to generally get \"bored\" when such interactions aren't available (caveats here because fish are incredibly diverse). \n\nThat's not to say that fish aren't sometimes \"unhappy,\" or to be more scientific, stressed, when living in fish tanks. But they are stressed for fish reasons, not necessarily the ones we project on them. For example, fish that live in groups but are placed in tanks alone can be very stressed, because in the wild being isolated means being in great danger of being eaten. Fish in aquariums without suitable cover may become very stressed, for more or less the same reason. If fish are crammed in with other, aggressive fish they may be constantly harassed and quite often may be physically injured. Bad food or water can make them ill. Insufficient swimming space may harm their physical development or make them feel trapped...although what \"sufficient swimming space\" means depends quite a lot on the species of fish. The right species of fish in a suitable aquarium will probably be just as happy as a fish in the wild, though. Certainly I have seen many aquarium fish that were obviously thriving--you can read the behavioral and physical signs if you know what to look for. \n\nAs for that study referenced by RalphiesBoogers, I'm unconvinced they were measuring \"boredom\". Midas cichlids are aggressive fish, and they were combining multiple fish into a constrained location. You'd expect increased aggression not due to boredom, but because fish were constrained in a small location and unable to space themselves out enough to reduce conflict. Adding more complexity to the tank would be expected to reduce aggression, not because of reductions in boredom but because more structure breaks up lines of sight and makes it easier for fish to avoid each other, and complexity also produces markers allowing fish to define territories... \"this rock is mine, that rock is yours\". This phenomenon has been directly documented in other cichlid species. ",
"I had a betta in one of those little bowls. I got sad for him and bought him a ten gallon tank with plants, light, and air filtration. He was very happy."
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8pdyov | why does being in the sun help with my depression? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8pdyov/eli5_why_does_being_in_the_sun_help_with_my/ | {
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"The sun light is very important because it helps our body to produce serotonin and melatonin, two hormons making us awake and more dynamic. It also configure our internal clock which is crucial for good and stable sleeping. There is even an illness called \"seasonal affective disorder\" which means that you're depressed because of the time and weather. So if you don't have that light, if you're always in a closed room, you will be lazy, depressed and can have more both physical and psychological troubles (for example gaining or losing weight, being bipolar, etc.) ",
"Something not mentioned yet is the Vitamin D aspect of sunlight.\nThe vast majority of people suffering depression are also suffering from Vitamin D deficiencies. The more sunlight you get, the more Vitamin D your body can generate. You can see a study here that goes over the correlation found via meta analysis of other studies.\n\n_URL_0_ ",
"Because your body still thinks you are a hunter/gatherer.\n\nWhen it is sunny a lot, like in the summer, food is more plentiful, and you need to be up and about getting some.\n\nWhen it isn't sunny so much, like in the winter, food is scarce, so you should mope around doing nothing to conserve energy. Hope you saved up enough food last summer..."
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fhib9d | why are transportation prices going down? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fhib9d/eli5_why_are_transportation_prices_going_down/ | {
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"Gas prices are because Russia and Saudi Arabia are in a price war, but the rest is simple demand-based pricing. Demand is low, so supply (e.g. open seats on planes) is high and prices are lowered to try and sell. \n\nIt's not the transportation company's responsibility to police travel.",
"The companies that operate these services are still businesses, and still need passengers to make money.\n\nThe logistics of running an airline or a train service are staggering. A canceled flight or train stop can have massive impacts downstream, as other flights/trains depend on that flight/train reaching the desitination so it can be used as the next leg of the journey. Many flights/trains have to keep flying/driving, even with no passengers, just to keep the system functioning.\n\nSince the _vast_ majority of the cost for flights/trains is fixed (it is the same whether you have 100 passengers or 1) it behooves the company to do whatever they can to get passengers. With demand super low due to COVID-19, they are dropping prices to try and get as many customers as they can."
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16j4ej | explain lows, mids, and highs for headphones to me. | I just don't understand the difference, at all. I've read a few things, attempting to understand it, but the people used more words that caused further confusion. Could someone explain what they are to me, possibly by using example or something of the like? Any help is appreciated, whether it be a link to a good explanation, or one written yourself, thanks!
Also, just remembered that I was wondering about this as well, what is sound stage, when referring to headphones? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/16j4ej/explain_lows_mids_and_highs_for_headphones_to_me/ | {
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"Lows are the bass, highs are the treble, mids are in between. \n\nFor lows, imagine a kick drum: thump thump thump\nFor highs, imagine tapping on a wine glass: tink tink, chimey \n\nUsually instruments have some of each, though. For example, the kick drum doesn't just go thump thump, you can also hear the fap fap (i know) of the beater hitting the drum and that is \"highs.\"\n\nNo speakers are perfect (headphones especially), so basically they will all render sound differently. You might have more lows or highs with certain models."
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2mh6lp | 9 billion dollar witness jpmorgan paid off. i tried reading articles but i just couldn't understand what happened. | What exactly went down here? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2mh6lp/eli5_9_billion_dollar_witness_jpmorgan_paid_off_i/ | {
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"It looks like JPMorgan bought and sold loans that should not have been, made money off of them, and didn't tell anyone that the loans were unsafe for banks. People lost a bunch of money and that's about the time the American economy dropped out. The witness referenced is a woman who saw that the loans were bad, reported it as such to her boss, who ignored the report, and that boss cost the company $9 billion.",
"[Rolling Stone magazine just published an article about it.](_URL_0_)\n\n",
"SHE WAS NOT PAID OFF. There, got that out of the way. \n\nAlayne F worked at JPMC and tried to stop them from committing fraud that helped crash the housing market in 2008. She wasn't allowed to talk about her work there after she was fired, unless the US government calls her as a witness. JPMC paid the government a **$9 billion** fine to stop them from calling her as a **witness** in the court case against JPMC. JPMC gets off for a mere $9 bil and the CEO & friends involved in the fraud aren't punished.\n\n\n(Full summary in reply.) "
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7dh4eq | why is it that different language groups make different sounds (onomatopoeia) - for example, a rooster's crow? why are they not universally the same? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7dh4eq/eli5_why_is_it_that_different_language_groups/ | {
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"Because how you hear something is heavily influenced by the language you live in. So the onomatopoeia you choose to represent that sound will be different in different languages. \n\nFor example many native speakers of Asian languages have a massive issue telling an English \"R\" and \"L\" sound apart. Many more non-English speakers have trouble telling \"C\", \"S\", \"Z\" and \"X\" sounds apart (and some native English speakers too). Etc. \n\nYou also have the fact that different letters and letter combinations make different sounds in different languages so while they onomatopoeia may be identical when spoken between two languages they will be spelled completely different. "
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ahb42q | what does having an extra exhaust pipe (2 in total) do for a car’s performance? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ahb42q/eli5_what_does_having_an_extra_exhaust_pipe_2_in/ | {
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"On normal cars with small engines, nothing except the look. The reason you'd NEED it on bigger sized engines is because they take in more air, use it to combust the fuel then they need to expell the air and pressure from the explosion. If the air isn't exhausted out fast enough then you restrict the efficiency of the engine and so the power is lower than what it could be",
"Nothing at all for four cylinder or less engines unless extremely poorly made. \n\nFor more cylinders than that there would be a marginal gain in performance entirely offset by the added weight. \n\nMind you, I still have two exhaust pipes just because I like how it looks. ",
"In most modern cars, engines come in what is called either an \"inline\" package or a \"v\" package, and this has to do with how many banks of cylinders there are, one bank or two.\n\nEach cylinder is going to have an intake and exhaust port, which lets fuel and air (the \"charge\") in and the exhaust gasses out. These exhaust ports are plumbed together, each their own pipe into a single pipe, by what is called a \"header\". This piece of exhaust plumbing is a single piece that bolts up against the engine along the exhaust ports. You need one per bank. That means an inline engine package is going to have one header, and a v package is going to have 2.\n\nNow, for the inline package, it makes the most sense to continue piping this one exhaust line past the O2 sensor, part of the feedback loop that tells the computer how much fuel to add to the charge, past the catalytic converter, that uses a honey comb of platinum to convert some of the smog producing oxides into carbon dioxide and water when it gets hot and these gasses come into contact, through the muffler, because if you think your tiny little lawn mower engine is loud... and out the back, away from the passengers and windows so exhaust gasses can't accidentally vent back into the car. The only reason you'd see two tail pipes in this arrangement is for aesthetics.\n\nA v package has the same need x2, so it would make sense to see two tailpipes. But of course, it's not that simple.\n\nFor low end, economically priced vehicles, the two headers would be combined into a single line out the back - this saves on material cost. This configuration is called a \"Y pipe\".\n\nEnter \"exhaust scavenging\". You see, when that exhaust port opens and the piston pushes the exhaust gasses out, those gasses are still at ~100 psi, and they travel down the pipe as a pulse. Behind the pulse, the gasses actually pull a little, tiny vacuum. THIS IS A PHENOMENAL THING, because once that pulse gets past the header, that vacuum will actually help clear the next cylinder that exhausts in that bank, because that tiny vacuum will help to pull the next pulse out. This means the cylinder is clearer of exhaust gasses than if the piston just squeezed it all out, meaning that cylinder has more volume available for the next cycle. It's all about fuel and thermal efficiency. And this applies to our inline package as well as the banks of the v package.\n\nBut hey! If we can scavenge the other cylinders of our own bank, why can't we scavenge the cylinders of the other bank, too? Enter the \"H pipe\" and the \"X pipe\".\n\nThe H pipe is two exhaust lines with a pipe that comes across and connects them. This improves scavenging and thus efficiency. It's an older design, but it is still common to see because it's most efficient at low RPM, which helps with your engine producing torque at low RPM, and that's important because most of your driving experience is at low RPM.\n\nThe X pipe is two exhaust lines where they cut into the tubing about half way and welded the two lines together. The lines effectively become one and then split again, as opposed to the H pipe which is more like a bridge. This also has a scavenging effect, but at higher RPM, which makes it popular on sports cars.\n\nYou can also buy aftermarket scavenging exhaust systems tuned for whatever you would like. Efficiency increases the closer to the headers the cross connection gets, but there are transmissions and driveshafts in the way, and that needs to be taken into account. And the diameter of the pipe is important, too - a large diameter pipe makes for big, slow pulses of gas, which isn't good for scavenging, whereas small diameter pipes make for small, but long, fast pulses, which increases scavenging efficiency, but there is a bottom end to that where there is too much gas and not enough room. Supercharged and turbocharged engines are dealing with so much volume of charge gasses and exhaust gasses that scavenging goes right out the door - just bolt on the biggest pipes you can afford, scavenging isn't going to help you here. This is why diesels have gigantic, straight pipes - they're all turbocharged these days.\n\nAnd in the end, you'll see H pipes and Y pipes and whatever you call those single pipes from inline packages come to the end of the exhaust. A lot of aesthetics are applied here. I've seen H pipes feed into a single muffler, and that single muffler exit two pipes. There's no need for that but for looks. I've seen a single pipe split into a Y after the muffler so it can exit out two pipes. And it's actually very common that cars will have a fake exhaust tip."
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bl1yaf | why does our vision distort things when we stare at something too long without blinking? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bl1yaf/eli5_why_does_our_vision_distort_things_when_we/ | {
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"the cells in your eyes that let you see things get fatigued over time. They just keep trying to send the same signals constantly and they stop working. Moving your eye even a tiny bit is enough to resolve this problem instantly since each cell is now receiving different wavelengths of light than they were.",
"I have a follow-up question if anyone knows,\n\nWhy do I have to make an effort to see and if I just relax my eyes, things get blurry and unreadable?"
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68gbfh | the difference between a private company vs a company that has gone public. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/68gbfh/eli5_the_difference_between_a_private_company_vs/ | {
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"Private companies are, as their name suggests, privately owned (either by the company's founders, some family members, or a group of investors). Public companies have expanded ownership to that of the public by selling shares on the stock exchange. ",
"A public company just means you, anyone, i.e. \"the public\" can buy and/or sell shares (ownership) of the company on the public markets, like the NY Stock Exchange. That is there is a market place where you can easily buy and sell ownership of the company. Think of a company like Amazon. You can go and just buy some ownership of Amazon, at a price through any broker., in a microsecond.\n\nBeing a public company also puts additional reporting and business requirements on your business to ensure transparency.\n\nA private company means it is not listed and \"the public\" cannot just buy ownership of it easily. Most companies are private. Now the owners of a private company can of course sell their shares as they see fit, but its not sold to broadly to the public and you have to make an individual deal with the owner, think like if you wanted to go buy ownership of your corner deli store, you'd have to go find the owner, and negotiate directly with them."
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6sfjku | how do microphone "pop filters" work? | How does putting a piece of fabric over your mic stop wind noise and plosives? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6sfjku/eli5_how_do_microphone_pop_filters_work/ | {
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" > How does putting a piece of fabric over your mic stop wind noise \n\nWind doesn't blow through fabric very well. Most people learn this from their experience wearing clothes.",
"A well-built microphone is Very sensitive to sound waves, and the metal mesh around it is for physical protection more than sound filtration. The 'fabric' is actually a foam; like a sponge. It's not necessary for microphones further than a foot away, but speaking into a naked microphone close to your mouth will yield loud pops with every P and pick up all the .. saliva slapping sounds you may make when you speak.",
"I want to add to the very good explanations with[ this short example.](_URL_0_) for people who might not know what you mean. Essentially \"pop\" noises are very sharp spikes of wind in addition to the sound. The microphone acts picks up the wind as well and that creates spikes in the audio. A pop filter stops the wind and only lets the vibration of the air (the actual sound) through. \n\nTry pulling your T-shirt over your nose. You still sound fine but blowing through it is very hard."
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di8kqu | how do doctors prevent getting ill from the patients? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/di8kqu/eli5_how_do_doctors_prevent_getting_ill_from_the/ | {
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"They sometimes get ill, but you'd be amazed at just how effective washing your hands can be. You also tend to build up a bit of an immunity, but the truth is that they get sick just like everyone else.",
"Washing hands, having awareness of germs that are airborne and staying healthy in general are some of the many things that doctors do. All in all, even having a healthy diet can help you, anything to strengthen that immune system :)",
"Face masks and hand sanitizer. If the disease is contagious and dangerous enough, additional measures can be taken, including a sealed hazmat suit.",
"Standard precautions for patient care involves several ways to prevent the spread of diseases, but the main one is washing your hands all the time. Healthcare professionals wash their hands before they leave any room and might even use hand sanitizer between rooms. \n\nBeyond that it's whatever is needed on a case by case basis. Gloves are always worn when you're going to be touching a patient or doing any kind of assessment on them. A mask is worn if the patient has something airborne or is coughing. There is also a disposable robe one can wear as personal protection equipment if the patient has somthing that can be picked up via contact (usually MRSA).\n\nThere's many others but those are what I've encountered the most often. It helps to be mindful of your surroundings and what symptoms the patient has",
"over time your immune system gets much stronger but also cleanliness and washing hands. one of the biggest things is don't touch your T zone (your eyes nose mouth, anything with a mucus membrane) but you also just don't touch your face or your head at all. this may seem strange but really try one day to never touch your face and you will realize how often you scratch or brush your hands through your hair, or rest your hands on your face, etc, learning to never touch your face is a big one",
"Constant, aggressive handwashing, and facemasks when appropriate.\n\nMost of the time when you get sick, it's because you touched something with your hands and then later touched your mouth, your nose, or some food you were going to eat.",
"* Sick patients are asked to wear a mask\n* Dr. wears a mask with sick patients\n* Dr. wears exam gloves\n* Dr. washes hands\n* Dr. keeps current with vaccines\n* All pt contact areas are disinfected with germ killer sprays/wipes\n\nIt's not 100%, but it's pretty good.",
"Other people have answered your question (hand washing, face masks, etc) I just wanted to add that it is very much a popular belief amongst all kinds of medical professionals that you will get a ton of minor infections in your first year or so of seeing patients. Doubly true for your first rotation around kids, those little germ factories.",
"We wash our hands every time we go into and patient room, and every time we leave.\n\nIf somebody has an infectious illness in the hospital, they often will have special \"precautions\" for their room. For example, if somebody has a diarrheal illness, they will be on contact precautions. This means that everybody that goes in and out will put on a special disposable gown and wear gloves while in the room. We might wear masks in rooms where people have illness spread by droplets.\n\nSometimes a kid sneezes right in your fucking face and you get sick anyhow.",
"In addition to all the precautions listed in other comments, the hospital I used to work at had foot pedals to control the hand washing sinks so you never had to touch handles either",
"When i used to work in a healthcare environment, strict hand washing, glove wearing, mask wearing, and being very mindful of your hands near your face. i blew my nose often to clear any \"debris\". i always sanitized the most common touched objects in a room (light switches, counter tops, mouse and key board, phones, remotes, chair arms, pens, keys, door handles, etc).\n\nalso understand how certain illnesses are spread. if someone has a cold/flu, you can catch it via contact and via air if they are coughing or sneezing.\n\nstomach flu can also be spread via contact and air (when vomiting occurs) so best to not be in the room with a pukey person. \n\nMRSA and most other common \"hospital\" illnesses are picked up via contact. PPE should always be worn with strict sanitation procedures followed.\n\n & #x200B;\n\nand dont be scared to tell someone to cough and sneeze the \"polite\" way. sneezing/coughing into your arms is great. using tissues is only acceptable if they are washing their hands after each use. and if they sneeze into their bare hands and dont wash em.....just throw the whole person away.",
"Surprised that nobody yet has mentioned: full and up-to-date vaccination, including the seasonal flu shots.\n\nA friend of mine had to show proof of recent immunization or titer test for sufficient immune response for a list of different vaccinations before attending optometry graduate school, or before starting clinical work assisting patients, both for his safety and that of his patients.",
"They are not protected. Drs get sick all the time. The other problem is that Drs are not allowed to call in sick, so they are forced to go to work sick, which endangers the patients. The system has Drs spread so thin, that an absence is a real danger to collapsing the day or there not being a Dr present. And before everyone goes nuts, yes technically they do have sick days, but you better have the Black Black and Ebola wrapped into one before you call in sick. The sick Dr is also required to call around to get a replacement. When he/she can't then they have to go in anyway so most don't bother. It is a bullshit system that hurts patients and staff.\n\nAlso you can wash your hands all you want. It does not protect from airborne illnesses or the gross keyboards. You can't constantly disinfect everything. There are too many people flowing through some areas. In my husband's hospital, they are three deep in the hallway on stretchers most days. Good luck keeping that clean. Patients are coughing, sneezing, shouting, barfing, etc all over the place. It is not a controlled environment and everyone gets sick all the time. He and the staff do their best, but they get sick a lot.",
"Doctor here, we wash our hands. A lot. \n\nAlso we beep loudly (think operation) when we see a colleague touching their face before washing hands.",
"Most take a ton of Sudafed, wash their hands consistently, and use the sanitize/hot-like-hell/boil your clothing setting on their washing machines.\n\nAlso, vaccinations and constant exposure during rounds/internship(s) + exposure to a host of common undergrad/grad germs on a daily basis during med school *tends* to lead toward relatively robust immune systems.",
"Protective clothing, vigorous hand washing, etc. all work to reduce the effect but doctors, nurses, etc. still get sick more than the average person just by the nature of their work. There are also times where you can also get an exposure through a needlestick or with a scalpel that the general public usually doesn't have to worry about. All in all, it is a risk of the profession mitigated by rules and precautions.",
"Also just to add to what everybody is saying here: only a certain percentage of hospital patients are sick with INFECTIOUS causes. A good deal of other patients have conditions like COPD, CHF, AKI on CKD that are not contagious.",
"My girlfriend is a GP and we just finished a pretty nasty bout of flu season and she didn’t get sick. She uses a butt load of hand sanitizer and when she gets home she immediately showers and washes her hair. \n\nThey certainly do get sick just like everyone else though.",
"It's a secret and I can't tell you because you aren't a doctor.\n\nIf you were, you'd know the answer."
]
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5ouf6j | lottery earnings, how does the irs/government look and treat them? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ouf6j/eli5_lottery_earnings_how_does_the_irsgovernment/ | {
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"lotto winnings are gambling winnings, taxed as ordinary income, but the food stamp system seems to have some holes that do not consider net worth, just income. Or perhaps they just dont monitor it well.\n\nThey were trying to update the law for food stamps in michigan to cross check recipients with lotto winners. Seems an oddly narrow fix, not sure if it ended up passing anyway.",
"All winning are treated as income. Winning a jackpot just puts in you in the top tax bracket for that year which means you are going to pay about 50% of it in taxes. This is for the USA only, most other countries don't treat winning as income so you keep what you win everywhere else. \n\nThe food stamp program is it's own program and has it's own rules about who is eligible. While they would consider your winnings as income, they probably don't see it as regular income. You made zero last year, you are going to make zero next year, this year is just a blip where you made money but because of expected earning next year, it doesn't disqualify you from benefits this year. \n\nMost likely rules to encourage people to move up and earn more without fear of being worse off for making a little more money or winning a prize and loosing more in benefits than what they earned.\n\nThe rules probably never considered a mega jackpot winner, let alone one that would continue to apply for benefits even though they are now a millionaire. "
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14xogq | why stockholm syndrome occurs | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/14xogq/eli5_why_stockholm_syndrome_occurs/ | {
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"text": [
"I think there are at least two parts to consider as to why Stockholm Syndrome occurs.\n\n\nFirst, imagine I kidnap you from your mommy and daddy (cause you're 5 years old). The news, the TV, your parents, and the police have all told you that if someone kidnaps you they will probably rape you, murder you, and torture you, and that your life is in grave danger. \n\n\nAnyways, I kidnap you and take you back to my house. It turns out that the reason I took you is because I'm a lonely old man and I haven't had anyone to talk to in 20 years. I tell you this and we talk for a bit about your elementary school and life. When you're hungry, I feed you, and since you've been good, I let you use the shower to clean yourself and I give you some spare clothes I bought for my grandson a long time ago. \n\n\nAt this point, you realize that I'm not as bad as everyone made me out to be. I'm just misunderstood. You're glad that even though I could have raped you, tortured you, or killed you, I instead fed you, cleaned you, and talked to you all day, and I even promised to let you go in a few days. This might lead you to have feelings for me: protective feelings, sympathy, empathy; you know that if the police find me, I will probably go to jail for the rest of my life, and you don't think I deserve that even though I did something wrong. So when you finally make it back home, you tell people that I'm not so bad and that I shouldn't go to jail. Others are baffled because I kidnapped you, but they don't know everything that went on between the two of us. This is also an expectations vs. reality conflict.\n\n\nSecondly, there is a psychological phenomenon called the Mere-Exposure Effect (_URL_0_). Psychological research has shown that the more someone sees something, the more preferential they become towards that thing. So, for instance, let's say I kidnap you for a week. Every day that week, you're going to see me and my routine. I get up to make breakfast, come visit you, give you some food, we talk, I go out. Just that fact that you see me everyday forces you to become more attached to me, even if you hate me for kidnapping you, because I'm the only reliable thing in your environment at the present moment.\n\n\nAnyways, I hope this answer helped."
]
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| []
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[
"http://en.wikipedia.org/wiki/Mere-exposure_effect"
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5epyel | what is linear and non-linear development in the context of software development? | I am currently learning about Git, and the term 'non-linear' keeps poping up. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5epyel/eli5_what_is_linear_and_nonlinear_development_in/ | {
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"That's very specifically a thing in version control\n\nIf your version control system sees the world in a linear way, then what happens is: you make changes, then I make a changes, then you make some more changes, like this:\n\n o (Start)\n | \n o Qkb\n |\n o pdpi\n |\n o Qkb\n |\n V (time goes this way)\n\nWhereas a non-linear VCS says that that's a simplistic point of view. In reality, we're likely to both start developing on top of what the program looks like at the start, and then we'll need to merge our changes:\n\n o Start\n / \\\n Qkb o |\n | o pdpi\n Qkb o |\n \\ /\n o Merge changes\n |\n V (time goes this way)\n\nIt's called non-linear precisely because history doesn't look like one neat straight line. That's all there is to it."
]
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| []
| [
[]
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|
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2jk9bf | why is the window of youth for a female (that is, the years of highest fertility) so short? | Why doesn't this window last into her 40s, but is concentrated in her late teens and early 20s? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2jk9bf/eli5_why_is_the_window_of_youth_for_a_female_that/ | {
"a_id": [
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"text": [
"For much of human history, a female who survived to childbearing age only had a life expectancy of making it to her late 40's or early 50's anyways.\n\nLife expectancy at birth was significantly lower.\n\nHaving a bunch of kids quickly after reaching sexual maturity works well. \n\nThere's no great benefit for a woman bearing her own children in her 40s when she probably has grandkids she can devote her resources to at that age.",
"Because having a baby is hard on your body. In your 40s, your body starts to ache and creak enough without carrying the extra weight of a human + fluid, and having all your organs pushed into weird places. Not to mention childbirth and recovery."
]
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70rrkz | why does flammable and inflammable mean the same thing? | As the title says, why the difference from words such as indestructible, invisisble etc | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/70rrkz/eli5_why_does_flammable_and_inflammable_mean_the/ | {
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"text": [
"because \"inflammable\" comes from \"inflame,\" and comes via [French](_URL_0_), whereas flammable comes directly from Latin and was only popularized relatively recently, because in English the \"in-\" prefix became a popular way to say \"not able to.\"",
"terrendos and justthistwicenomore have explained it, but I will try to explain more fully. Take the \"un-\" prefix, for example. It means \"not,\" but not at the beginning of every word. Uncle does not mean \"not cle.\" Un can also be in the \"uni-\" prefix, meaning \"one.\" As in universe, unicycle, uniform. Things that are uniform are all formed as one. It does not mean \"not iform.\" I'm sure this is obvious, but I wanted to use more obvious examples.\n\nMy memory is that it changed around the 1980s. Before that signs would warn that something was \"inflammable,\" meaning \"able to be inflamed.\" But apparently there were sometimes people who would think \"in\" meant \"not,\" as it usually does at the beginning of words, and think the word meant \"not able to flame.\" So signs began using \"flammable\" meaning \"able to flame,\" so there would be no confusion. At the time I heard that flammable was a made-up word, and the real word was inflammable. But that may not have been correct. \"In\" does not mean \"not\" in other words, for example when it is part of the \"inter-\" prefix, as in internet and interstellar."
]
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| []
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[
"http://etymonline.com/index.php?term=inflammable&allowed_in_frame=0"
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[]
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7ro1ug | why is it we can it people into a medical induced coma but not any medical use to get them out of coma? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7ro1ug/eli5_why_is_it_we_can_it_people_into_a_medical/ | {
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"text": [
"Medically induced coma is done through drugs(barbiturates). Drugs wear off, patient wakes up. Comas cause by accident are a result of damage to the brain which is slow to repair/rewire if it ever does."
]
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| []
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25ch5q | what was an average german soldiers mindset pre, during, and post ww2 | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/25ch5q/eli5_what_was_an_average_german_soldiers_mindset/ | {
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"There were numerous \"types\" of german soldiers, Nazi Germany's armed forces being one of the most convoluted and complex militaries ever. I'm not sure what type of German soldier would be \"average\", but I'll stick with the Wehrmacht soldiers for now.\n\nFor the Wehrmacht part of Nazi Germany's armed forces I'd imagine the mindset to start out as a positive \"can do\"-mentality - \"let's liberate the Sudeten Germans!\", \"Let's conquer Poland!\", \"Let's invade England!\" - which turned into pessimism and fear as the war dragged on. \nBy all account, the German soldier was highly motivated yet (dare I say it?) not a psychotic monster at all. Political indoctrination and racism were kept at arms length due to the officer-corps being composed of old noblemen - these guys wanted little to do with Hitler and his cronies. \nSo, the average Landser (a nickname for Wehrmacht-soldiers) was just like any other soldier in any other country's army: a young man stuck in a terrible position. Accounts I've read speak of Wehrmacht soldiers holding the enemy in high regard - at least on the western front - which might explain why so few atrocities were attributed to the Wehrmacht. In general, you could say that they were mostly OK guys fighting for a terrible regime, so they were more \"tragic\" than \"evil\".\n \nThat having been said, some elite troops were a different matter though. The Waffen-SS was extremely politically and racially motivated. These guys have been responsible for some of the more poignant war crimes commited on both the Eastern and Western fronts. \nThen there were the Einsatzgruppen: small groups of Wehrmacht soldiers, SS-men, police troops and volunteers who were composed for only one reason: to kill jewish people in conquered territories. These guys were a different breed - one might even go so far as to say they weren't even soldiers to begin with. Then there were some Wehrmacht units that were used to mop up resistance or partizans. Those units soon became disillusioned, turning to booze and becoming increasingly violent as time progressed. "
]
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1zk52n | if the us has control over icann can they take down any site? just hypothetically could they take down _url_0_ | Hypothetically could they? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1zk52n/if_the_us_has_control_over_icann_can_they_take/ | {
"a_id": [
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"text": [
"They *could* remove them from the root DNS servers (not sure about the legalities of this, would probably cause a huge backlash about freedom of speech and freedom of information etc). But that would only stop people from reaching it by going to _URL_0_. Connecting directly via IP address would still work. And there is nothing stopping someone else hosting a DNS server that has manual entries for _URL_0_."
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"thepiratebay.se"
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br617g | how were computers “commanded” before computer languages existed? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/br617g/eli5_how_were_computers_commanded_before_computer/ | {
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"A computer by definition has some kind of command process, or language. Even simple indexers, analytical engines, and other predecessors of actual computers. If there's not some way for commands to be executed, even just sorting, it's not a computer at all.",
"Computers always run on what is called \"machine code\", the actual values which make the computer components behave as desired. At this stage it is just like flipping electrical switches at the start of a long chain reaction.\n\nThe secret is that computers *never changed from that.* Computers do not \"think\", they do not understand anything, they don't \"obey orders\" any more than an electric winch obeys an order to pull on something when it is turned on. Computer languages and code are just abstractions to allow people to more easily construct logical processes than putting the machine code together directly.\n\nImagine a purely mechanical calculator, something that adds and subtracts numbers via gears and levers. The numbers to be calculated together are indicated by the positions of the gears at the start and that is in essence what computers are doing. The difference is that it is much faster, the parts are smaller, and it is done without moving parts using semiconductor switches.",
"Define computer language and computer. \n\nIf you want to be really technical, computer used to be a profession humans did, rather than being a machine. \nThe first computer language was telling Dave to add these two numbers together and divide them by whatever Larry came up with and so on. \n\nWhen it first started, an electronic computer did one thing, it had wires attached to the logic gates. \nTo make it do something different, you had to pull out all the wires and basically rebuild the entire computer. \n \nLater on, rather than rebuilding the computer they just made it really easy to pull out the wires and plug them in differently. \n \nLater on, instead of pulling out the wires, they just made it so you flicked a few switches so the wires would connect differently. This is probably where you could argue where the modern computer language existed. \n \nLater on, they had the machine flip the switches based on holes punched in a card. \n \nLater on, they had a machine read what you wrote and make the holes for you (though by then some of them weren’t even physical holes anymore)\n\nLater on, they had a machine read what you wrote, and re write it so a bunch of specific machines could punch their specific holes. \nAnd that’s a modern programming language. \nAt the end of the day a CPU op code is just an set of switches for a CPU. \nAssembly language is translated in those codes. \nAnd a modern high-level language gets translated into assembly language.",
"A computer processor, at it's most basic level, has a bunch of hard-wired commands built into it called an \"Instruction Set\". These are basic things like \"Load data from here\" \"Add these values together\" \"Move data to here\", a big list of operations that, together allow the processor to perform any task you can throw at it.\n\n* Machine code\n\nThese functions can be harnessed by directly talking to the processor in a language it understands, and the bottom rung of this communication is something called Machine Code. Literally ones and zeroes. Binary. \n\nThe documentation for a particular processor will include a table of information saying what binary input will equal a particular instruction set instruction.\n\nSo you can in theory program a processor right down at the bottom rung level, using direct machine code input. \n\nThe first home PCs were programmed this way, like the [Altair 8800](_URL_3_) or the [IMSAI 8080](_URL_2_) using those switches at the front. \n\nAs you can imagine though, programming a computer instruction by processor instruction (which might need several separate instructions to simply add two values together) is a long, long process, very prone to errors. Get a single zero where you should've had a one, and that's it. So they improved things a little. \n\n* Assembly Language \n\nThis was the next step up. Rather than having to look up what binary code equals a particular instruction and actually writing the code in binary, an assembler allows you to write those instructions directly, giving a much more human-readable result to your code. Rather than a string of binary code, an assembly instruction might now look like this: \n\n MOV RB, 61h \n\nThat means basically \"load location 'RB' with the value 61H\" Still doesn't make a lot of sense if you don't know what any of those instructions do, but it's far more digestible than a list ones and zeroes, which you'd have to go back to a lookup table to work out what they even mean. \n\n A random trivioid here is that Rollercoaster Tycoon was written entirely in assembly language in order to maximize performance. If you're writing directly in the processor's instructions, which you are doing in assembly language, you can make every last instruction count, and make the whole thing as efficient as possible. This is why Rollercoaster Tycoon always ran very well even on pretty low end hardware back in the day, while still looking very impressive. \n\nYou'd type Assembly Language into a program called an Assembler, which would then output (or assemble) the machine code ones and zeroes for you. \n\nSo that's assembly language. More digestible than direct machine code, but still pretty hardcore, because turning instructions like \"move data to here\", \"load this area with data\", \"add these values together\" into something like, I don't know, a copy of Windows, or The Witcher 3, seems almost impossible. It is how all computers work though at the bottom level, all processors no matter how fancy the programming interface you use is, use machine code at the hardware level. \n\nNext level up. \n\n* High-Level Languages \n\nThese are basically modern programming languages like Visual Basic, C, Pascal, Python, and so on. \n\nThe whole point behind a high level programming language is to take the rather abstract and alien processor instructions, and lay over it a nice (relatively) easy to understand language that behaves as a human operator might expect. \n\nBut the difference is, now the higher level programming language instructions (or 'commands') don't necessarily have to match up with the instruction set the processor uses. That's not their point. The point of them is to make a more intuitive framework that you can use get the task you want the computer to do down in a way that you understand, and then the language 'compiles' that code you've written into a big tottering pile of machine code that the processor can understand. The language can consist of any number of commands, and functions that make writing a program more easy, and some languages will have commands that more suit it to particular tasks (which is kind of why multiple higher level programming languages exist in the first place, to cater to different use cases).\n\n* Visual languages \n\nArguably a level above even higher level languages that would be visual languages. These are things like [Labview](_URL_1_), or the language included with the Lego Mindstorms kits, [Robolab](_URL_0_). \n\nThese go a step further by giving you a visual interface, with boxes you can drag around and lines you can drag between stuff to give an even more human-friendly method of telling the computer what you want it to do. \n\nThe further these languages go from machine code, the less efficient they might be, but the more intuitive and understandable to the average human they ought to be too, so it's swings and roundabouts. \n\nAll these languages do is output machine code though because even now that's how the processor does its thinking. The languages just do it, so you don't have to.",
"Programming actually existed before computers did. [Ada Lovelace](_URL_0_) is credited with creating the first algorithm intended to be carried out by a \"computing machine\". However at that point this machine was only theoretical and had not yet been built. So when computers were eventually built, there was already a procedure in place for commanding them."
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37dok7 | why the us is being blamed for isis | It seems that [these comics](_URL_0_) blame the US/Israel for the existence and actions of ISIS | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/37dok7/eli5_why_the_us_is_being_blamed_for_isis/ | {
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"Basically the US took out a major government and didn't put it back. That left a \"power vacuum\" which ISIS filled. ",
"The War in Iraq destabilized the region. When the U.S. pulled out of Iraq it left behind weaponry and military vehicles, which are now in the hands of ISIS. \n\nThe U.S. armed Syrian rebels who they claim they thought were fighting for human rights and against Assad. Those guns are now being used by ISIS.\n\nThe U.S. allies it self with Saudi Arabia and Qatar. Both countries have been linked with funding ISIS. \n\n_URL_1_\n\n_URL_0_\n"
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"http://www.washingtonpost.com/world/national-security/cia-begins-weapons-delivery-to-syrian-rebels/2013/09/11/9fcf2ed8-1b0c-11e3-a628-7e6dde8f889d_story.html",
"http://www.businessinsider.com/us-weapons-likely-fell-into-isis-hands-in-ramadi-2015-5"
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fxzajv | why is there so much latin written across our modern world? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fxzajv/eli5_why_is_there_so_much_latin_written_across/ | {
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"This can be traced to the Roman Catholic Church. In Medieval Europe Priests had to learn Latin because Bibles were written primary in Latin. This also made it a de-facto universal language because priests from all corners of Europe spoke the same common language.\n\nLatin was actually already mostly a dead language by this point and very few people spoke it. The Catholic Church revived spoken Latin to serve it's own purposes but got the pronunciation quite wrong. The Latin we frequently hear is referred to as 'Church Latin' vs 'Classical Latin'. As an example V's in Classical Latin are pronounced as W's, so Caeser's famous phrase veni vidi vici (I came, I saw, I conquered) would likely have been prounced Weni Wedi Wici in Caesar's time.\n\nTo learn to read the Bible or deal with the Church on any kind of serious or political level you had to understand Latin, so it became a language learned by not only the clergy but the Aristocratic class.\n\nOnce universities were established they would teach Latin as a kind of intellectual and universal language of the age. The most learned individuals therefore would all speak Latin and to a degree used it as both code and as a sign of professionalism.\n\nThis is why Latin phrases are so pervasive in things like Government, Law, Science, and Medicine.",
"The Romans had a pretty profound impact on modern Western society, more than most people realize. Obviously Latin was the language of the Catholic church, but the Roman Republic was the basis of the form of government most of the world uses today, which is often why you see it in governmental matters. Roman law formed the basis of modern civil law, hence its appearance in courthouses.\n\nLatin was popular during the Renaissance period as people rediscovered art and architecture from the ancient world, even apart from religious matters, and as Greek and Roman philosophers were looked to during development of the scientific method, Latin and Greek became useful sources for classification nomenclature (two words with Latin roots themselves!).\n\nModern English is a mix of a bunch of old German and a bunch of Latin (directly from Latin, or from bits of French and Spanish that worked their way in) to the extent that, when I took Latin in school, it was usually pretty easy to find an English vocabulary word with a similar meaning to any given Latin word."
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2l1oo0 | do muslim women pray like men? | I work in a warehouse with a large number of Muslims and every day several of the men go and pray at sunset yet none of the women do even though they out number the men 2:1 and a lot claim to be deeply religious. It got me thinking and I cannot ever remember seeing a women pray in the way men do or see it depicted in media.
If they do not, why? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2l1oo0/eli5do_muslim_women_pray_like_men/ | {
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"Muslim women aren't as obligated to go to the mosque as men. Also, a lot of Muslim women prefer not to be seen by non-relative men while praying, and since they pray at home, praying is much faster. If you go to a mosque you'd find the women have a separate entrance which is closed to any man or media."
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1shk7x | why does a phone trace take so long if there's data constantly going back and forth? | If you're talking to someone on a phone, you must know where the phone is. How else could the phone send your audio to the right place? So why does it apparently take so long to trace the location of a call? And how does it work, anyways? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1shk7x/eli5_why_does_a_phone_trace_take_so_long_if/ | {
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"You've been watching too many cop dramas.",
"That is just a movie embellishment to add suspense or drama to the situation. Unless the phone company is demanding a warrant, it would not take long for them to figure out where you called from."
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5ngsnl | why is it when we are younger we like sweeter food and can eat large quantities of them. but as adults we tend to like more fuller and bitter flavors, and sweeter foods can sometimes be "too rich"? | Edit: Thanks for all the responses everyone! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ngsnl/eli5_why_is_it_when_we_are_younger_we_like/ | {
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"I'm only 20 but have definitely began to experience this. Hopefully someone has some answers! ",
"There are a few theories. One is that children have less developed palates. Adults are able to appreciate the subtle and savory flavors of bitter foods. Kids dislike them because they can't taste the entire flavor profile, opting for simpler sweet foods. For adults, those sweet foods are overwhelming because they lack subtly. Another theory is that children crave sweets more because the body craves sugar when it's younger, at the point in development when humans need loads of diverse sugars.\n\n^(Source: I read an article online a while ago, and everything on the internet is true, right?)",
"It's a evolutionary thing. In the wild, bitter foods are often poisonous. Because children are often too young to have learned how to tell dangerous from safe plants, they rely on the taste of the plant. This is why they often highly prefer sweet foods",
"I heard it was because as a child the sensory stuff that tastes when things are “too sweet” hasnt developed yet, and wont until early adulthood. ",
"In nature the most common sweet foods are fruits, which evolved to be sweet so animals eat them and spread seeds. Most bitter flavors in our food are produced by alkaloids, many of which are poisonous. Therefore sweet foods are generally safer than bitter foods, because plants don't want to poison the animals that help them propagate. Since children are smaller than adults and therefore can be poisoned more easily it makes sense for them to avoid bitter foods and be drawn to sweeter and therefore safer foods chemically.",
"Breast milk tends to be slightly sweet (supposedly, can't say for myself.) Which may explain a childs preference for sweets. Another factor is that children have a higher density of taste buds, especially infants. There is a higher ratio of nerve ending per square mm in children and infants. That's why babies tend to put things in their mouths. With a higher density of taste buds, any new flavors can be very intense. That's why when a child tries something new, they're more inclined to not like it. Sugar and sweets are a very simple and familiar flavor profile to them, so that's why a child will tend to choose a sweet over something else. ",
"Just to add to everybody and climb onto the evolution train, things that are carbohydrate dense enough to taste \"sweet\" in nature, tend to be very caloricly dense",
"The real question I have is why I, 35, haven't apparently discovered this. There are some sickeningly sweet artificial candies I don't like, but I'm a 2.5 spoons of sugar in my coffee kind of guy. It frankly *baffles* my mind that people not only drink but *choose* to drink dry red wines and pay a lot of money for the privilege. Same with most beers, which are bitter and utterly irredeemable to me.\n\nI once went to a wine tasting with several friends my age, and we all got flights of red wines. There was one that all of them were cooing on about how good it was, whereas to me it tasted just as bitter and tongue-numbing as the other reds. I honest-to-God thought they were fucking with me. One of those same friends frequently can't stand sweet drinks I like, such as a vanilla cream soda or similar.\n\nSo strange to me.",
"I'm 36and have never thought \"that's too sweet.\" I love sugar... but live in sadness without sweets because I'm trying not to be fat :(",
"I don't recall where I heard it exactly, I think in /r/todayilearned, but basically as a kid, you can't tell when something is overly sweet, and so your body doesn't send the signal to stop. That's why kids can eat too much candy and get a stomach ache. Adults in the other hand have a reaction that causes the sweet things to taste gross or overwhelming, hopefully stopping you before you ingest too much. \n\nTl;dr - you develop the ability to stop yourself from eating too much sugar when you grow up",
"You crave sugar as a kid because of bone growth\n\n_URL_0_",
"[Article worth reading about this](_URL_0_)\n\nScientific evidence shows that children not only have a stronger preference for sugar than adults – but that sweet-tooth is hardwired from Day One.\n\n\"We know that the newborn can detect sweet and will actually prefer sweeter solutions to less sweet ones. The basic biology of the child is that they don't have to learn to like sweet or salt. It's there from before birth,\" explains Julie Mennella of the Monell Chemical Senses Center.\n\nUnlike adults, who often find overly sugary things unpleasant, Mennella says kids are actually living in different sensory worlds than adults when it comes to basic tastes.\n\n\"They prefer much more intense sweetness and saltiness than the adult, and it doesn't decrease until late adolescence. And we have some evidence they may be more sensitive to bitter taste,\" Mennella says.\n\nA reason for this may be that a preference for sweet, caloric substances during rapid growth may have given children as an evolutionary advantage when calories were scarce. That notion is supported by the fact that sugar doesn't just taste good to children -– it actually makes them feel good, too.\n\nMennella's research has shown that sugar is a natural pain reliever in children, and many hospitals even put a sweet-tasting liquid in a baby's mouth during circumcisions or heel stick procedures to help lessen the pain.\n\nWhen researchers gave adults and children water mixed with various amounts of sugar, adults preferred sugar concentrations similar to that of a can of soda, while finding higher concentrations too sweet. By comparison, children preferred at least twice that concentration, and younger children had virtually no limit.\n\n\"You can keep putting sugar in to the point where you can't dissolve it in the water anymore and they still like it,\" says Sue Coldwell, a researcher at the University of Washington who has studied kids and sweets.\n\nBut there seems to be an age limit on the super-sized sugar preference.\n\nColdwell and her colleagues suspected that sugar preferences changed during adolescence. They checked a bunch of indicators, like body image and hormones, and then they checked bone growth. They gave the sugar-water test to adolescents while simultaneously measuring a marker of bone growth in their urine. What they found was that kids who were still growing preferred sweets. Those whose growth had already stopped –- around age 15 or 16 — had taste preferences similar to adults.\n\nExactly how this all works is still somewhat of a mystery, but Coldwell says that one important clue lies in the discovery that growing bones actually secrete hormones that can influence metabolism. Other well-known metabolic hormones like leptin and insulin have been shown to act on brain areas that control cravings and appetites, and even directly bind to the tongue, where they affect the preference for sweet tastes. Coldwell suspects that hormones from growing bones may be doing the same thing. In other words, it's not your kid's fault he raided the cookie jar – the hormones from his growing bones made him do it.\n\n\"I don't know for sure, but I am very suspicious that the bones are somehow telling either the brain or the tongue that there is energy needed for their growth and signaling for that preference to increase,\" says Coldwell.\n\nThat's not to say a kid can't overdo it. In a modern world of calorie overload and childhood obesity, cravings for sugar are no longer the evolutionary advantage they once might have once been. But if the goal is to get children to reduce their intake of sugar, researchers say understanding the biology behind their cravings is the first step.\n\nTL:DR - They think we're genetically programmed to want sugar and that our intense childhood craving for sugar stops when our bones are finished growing."
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3dj0oi | why is it hottest when the sun begins to set instead of when the sun is at its highest point? | Example: 12pm 86 degrees vs. 4pm 101 | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3dj0oi/eli5_why_is_it_hottest_when_the_sun_begins_to_set/ | {
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"The atmosphere takes time to heat up and cool down. While the sunlight may be more indirect in the afternoon, the atmosphere overall has been exposed to more sunlight at that point than it has at noon.\n\nRight at Noon, you've got \"most direct light, preceded by almost direct light, preceded by indirect light.\n\nAt 4ish, you've got \"almost direct light, direct light, almost direct light\"",
"Because by 4pm, the earth, the air, nearby bodies of water, man-made structures, etc. have been baking in the sun all day, so they are releasing more heat than they were at noon. They finish releasing their heat during the night and then take a while to warm up again the next day.",
"Because in the evening there is residual heat that stays trapped, cities are worse for this than deserts because of all the asphalt that retains heat longer than sand, this is why a 105 degree desert turns freezing at night while a 95 degree city doesn't get below 75 all night. The sun is more forceful at its highest point but the surroundings haven't collected all of the heat yet by then. "
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5c3vph | why do people always want the newest available thing, whether it be a gadget, vehicle, tool, toy, etc? what theory or concept is this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5c3vph/eli5_why_do_people_always_want_the_newest/ | {
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"Because people want to show off and maintain or increase their social status (or 'importance' of the group).\nPeople like to feel important and they more so like to feel better than others, especially their peers. So they try to show off by buying trinkets and new tools. \n\nThis is partially evolutionary. The need to be part of a group and be regarded as important and wealthy (in the sense of stability and health) is/was important for procreation and attracting of partners. \n\nIt's also partially a cultural thing introduced to us at a young age by advertising. All with the primary purpose of making us buy more. This plays into that evolutionary mechanic, which is why it works so well. ",
"Obsolescence, they make you think your product is obsolete and you will be out of date even if the thing you have, does exactly the same things as the new one."
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6viwvc | why do phone cameras (for example) make close objects appear much further than they really are when compared to the naked eye? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6viwvc/eli5_why_do_phone_cameras_for_example_make_close/ | {
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"Selfies.\n\nThey have wide angle lenses because people want to be able to hold their phone out and get a picture of themselves. It's also important to support video chat, you don't want to video chat with a life-size face, only the mouth and nose show.",
"There is a principle in photography called \"compression\". Why I cannot explain the actual physics of the situation, I can explain the end result. The wider a focal length of a lens the less compression. The more telephoto the focal length the more compression.\n\nThe focal length of a cell phone camera is quite wide leading to a shrinking effect in the compression (approx 4.2mm depending on the iPhone you have). A 50mm lens is considered to be approximately \"normal\" to vision. Meaning that the compression level is about what we see with the naked eye. A longer lens, 100mm for instance will have greater compression. This means objects in the back ground of the subject will appear even larger than they do IRL. \n\nPS. All of this assumes a camera sensor size of approximately 35mms or using 35mm film. Therefore the cell phone camera lens of 4.2mm is approx 28mm equivalent. "
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3n9e9h | the exact difference between cosplay and just fancy dress. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3n9e9h/eli5_the_exact_difference_between_cosplay_and/ | {
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"Cosplay stands for costume play. You are dressing up as a character, in a costume.\n\nFancy dress is just that, fancy. It has no, at least stated, tie to emulating a fictional character or thing.",
"Cosplay has to be a character from fiction or pop culture, or a variation on such a character. Cosplay should be home-made from scratch. I'm sure there's more distinctions, but I'm not that into cosplay anyway."
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7qay8y | how much of nutritional value depends on chewing? how much work of the digestive process depends on how finely food is chewed? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7qay8y/eli5_how_much_of_nutritional_value_depends_on/ | {
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"Okay, I took a physiology class in college and I believe I know the correct info so I'm going to take a stab at this one.\n\nChewing your food helps with digestion in two main ways. First, when you first begin chewing your food, a signal is sent from your mouth to your brain telling it to prepare your stomach for the meal that's about to go down. This depends on how much the saliva in your mouth breaks down the food in your mouth, which will of course depend on how much time the food spends inside your mouth. Chewing and letting the food dissolve in your saliva will send signals to your stomach telling it to release these or those enzymes which will more or less be custom made for the specific food that you're currently eating. Scarfing down your food without chewing will cause your body to just break it down with whatever it has readily available, ie whatever enzymes and stomach acid content that it can muster up in the moment with the info it's been given.\n\nThe second way is the physical breakdown of food by chewing. The amount of chewing needed to get the highest possible output will depend on how fibrous the food is. Very fibrous food like kale stalks or black beans or corn kernels will oftentimes end up in the food output (poop) because they were simply not physically broken down enough by chewing and too tough to be broken down by acids and enzymes alone. And if they're not broken down in your poop, you better believe that you probably missed out on nutritional value (to be fair, not sure kale stalk has too much nutritional value. \n\nIn short, meal for meal, the nutritional value won't differ too terribly much depending what you're eating. Over the course of weeks, months, years, however, chewing absolutely will make a huge impact on nutritional absorption, not to mention the positive impact it will have on your digestive tract. Also worth mentioning, over chewing will cause problems of its own, as we are meant to be eating solid food at the end of the day. "
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6dsk32 | urination/defecation with coma patients | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6dsk32/eli5_urinationdefecation_with_coma_patients/ | {
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"text": [
"Catheter for urination, tube stitched into your body for fecal movement. Even with eating and nutrient intake, it is typically done through a tube, ending where necessary. "
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3xit6s | why are higher values of money made with paper rather than coins, if coin money lasts longer? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3xit6s/eli5_why_are_higher_values_of_money_made_with/ | {
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"Paper is cheaper to make and people don't like carrying coins around. In the US the Sacajawea dollar was tried for awhile a few years ago but never caught on because most people still preferred paper bills. ",
"I'd assume because paper is harder to counterfeit. \n\nIf 100$ coins were steel, it would be easy to make a mould and DIY a few thousand. \n\nAnd because precious metals like gold and silver no longer directly back the currency, paper is a cheap way to create national currency. ",
"Money in the United States is printed by the federal Reserve as \"notes\". This signifies the debt the holder owes to the federal Reserve in allowance to use that note as proper tender, as the US government does not itself back the monetary value of said note behind a gold standard any longer. \n\nYou cannot owe anything to the reserve while holding coins, as they usually meet or exceed their own value in physical content, which means it backs itself. "
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4l4831 | why were people in the past so concerned about stopping masturbation? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4l4831/eli5_why_were_people_in_the_past_so_concerned/ | {
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"People think that achieving a state of pleasure or bliss with basically no consequence is inherently unnatural and wrong.",
"In the Bible it was the \"sin of Onan\", and for many people that was enough justification. It has been argued that circumcision was invented to deter masturbation; though if that's true, the inventors hadn't heard of natural lubricants ... ",
"They still exist. Look at this flyer and soak it up in all its crazy glory: _URL_0_ \n\nThis sort of restriction can't be good for developmental skills and will tweak the individual's perception of a healthy sexual appetite.\n\nI have a hard time believing that masturbation is limited outside of religion.\n\nChurches need kids to grow their numbers, and this is an extreme way of reinforcing that sex outside of marriage is a sin.\n\nThe root of it all would be a misunderstanding of anything sexual outside of marriage to be a sin including any sperm expelled anywhere outside of a wife. I imagine that some of it also roots in living a virtuous life where the individual makes decisions from a holy source and not sources based in worldly satisfactions.",
"Well there are actually a lot of reasons.. Most of them involve religion and pseudo science.\n\nA long long time ago, virginity was a virtue that was valued in many societies. These societies believed that a \"good women\" should be loyal (to her hubby) chaste, modest, and submissive. \nLater the chaste criteria was applied to the good Christian. \n\nSome people used biblical stories such as the sun of onan, to \"prove\" that God viewed masturbation as a sin. Others used \"science\", the most common theory for why masturbation was bad was the explanation involving the humors. \n\nSo medieval societies believed that there are 4 humors in the body, they are blood, yellow bile (urine), black bile (feces) and phlegm. The four must be in balance for a person to be healthy. Now spilling your seed outside of a women disrupted this balance. (Spilling your seed inside is okay because somehow the humors she releases would balance out the ones you lost) prolonged masturbation would lead to health issues such as blindness, and overall weakness. (Google limp masturbator) so.. \n\nThen there are the protestians who believe that the only way for your life to have meaning is to work hard, and one should spend every waking moment working. Seeking pleasure, (or being lazy) was seen as sinful. Thus masturbating (clearly an act of pleasure) is a sin because you are wasting time.. And energy....\n\nThen you have a mashup of all these ideas in the Kellogg's era...\n\nSo yeah :3",
"The sin of Onan was that he \"wasted his seed\", which was bad because his seed was needed to make babies. It's the same reason why oral and anal sex has traditionally been viewed as deviant, and the reason why birth control is still frowned upon in some religions: you are taking control over conception which should be in God's hands. This is because in order for religions to spread, they need lots of practitioners-- babies born into the religion would be an excellent source of practitioners.\n\nMoreover, being able to give yourself pleasure was seen as deviant and fallen because you were supposed to be preparing yourself for a life serving God. In some religious groups, masturbating was seen as particularly bad because we really shouldn't be enjoying our earthly lives that much.",
"If you can convince people that their basic desires are sinful and that you have the path to salvation, you control them.",
"From a Catholic point of view, it is because it doesn't involve a husband and a wife with a possibility of procreation. This is actually pretty much what makes anything sexual a sin in Catholicism, if it doesn't meet all the following-- you must be male and female, you must be married, and whatever you are doing must be able to result in a child (if you are physically capable of having children).",
"From the wise words of [Diogenes](_URL_0_) after being told not to masturbate in public: \"If only it were as easy to banish hunger by rubbing my belly.\"",
"The key problem would be the motivation behind masturbation. Jesus tells us in Matthew 5:28 \"But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart.\"\n\nStrictly speaking masturbation as a physical act *isn't* wrong. There isn't much in the bible about it, besides Onan (which others have explained). The bigger issue is lust; what do you think of when you masturbate? Someone you're not married to? If so then according to this teaching you are breaking the 7th commandment and committing adultery. ",
"What do you mean by \"in the past\"?\n\n_URL_0_",
"Remember, this is how we got widespread circumcision in the US. Apparently we were suckers for English imports 100 years ago, because the Victorians promoted the snip as a way to lock up the movable skin on your Johnson and desensitize the head - all to prevent the insanity and hysteria that was bound to occur from enjoying yourself. \nIt certainly hasn't stopped a good deal of men from trying. \nStill seems like a dick move (heh) to rob a bunch of guys of the full experience.",
"Population growth of like-mined people was imperative for adding strength to one's society / belief structure. "
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30pdoi | why does my throat randomly make weird gargling sounds?? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/30pdoi/eli5why_does_my_throat_randomly_make_weird/ | {
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"That's your inner demon. It can only be silenced by cleaning your room.",
"Short answer: Nobody knows.\n\nLong answer: The most likely explanation is gas escaping from your stomach due to a weak lower esophageal sphincter (LES) muscle, similar to what happens in GERD (\"acid reflux disease\") with TLESRs (brief relaxations of the circular muscle that prevents stomach acid from moving up your throat). There may be a relationship to stress, e.g. stress hormones causing that muscle to relax when it shouldn't, which would explain why it happens at awkward times. However, as far as I've ever been able to find, nobody has ever researched this issue, so this is all my personal, albeit educated, speculation.\n\nThere also seems to be a related issue in which people with this problem are unable to burp voluntarily--and often unable to burp at all, unless it's just prior to vomiting. This also suggests to me that it's a problem with the nervous innervation around the LES.\n\nIf you begin feeling uncomfortable due to pressure in your stomach or feel as if you're going to vomit, you can relieve the pressure by sticking a finger down your throat in the bathroom. This will make you \"vomit,\" but if you have the same problem as I do, you'll just make a loud burping sound as a large amount of air is expelled. If you vomit or begin to feel acid moving up your throat, you should stop doing this because chronic damage can occur. I also try to take an antacid a little while beforehand, just to be safe in the longterm with respect to protecting my esophagus from my stomach acid. This is not medical advice, and I am not a doctor; it's just what I do for myself with what sounds like a similar issue. **You should speak to your doctor about your issue to make sure it's nothing else, such as GERD, and of course also before starting any medication.**\n\nWe call this \"horse colic\" in my household because horses have a similar issue where they aren't able to release air trapped in their stomachs, and there's no name for it in humans.\n\nSource: Medical student with the same problem, had it for many years, literature-searched it myself more than once, and consulted several specialists, including a gastroenterologist and an esophageal manometrist, to no avail. I've yet to meet a doctor who reacts in a way other than looking at me as if I might be crazy, and I've explained it to about six different physicians over the past few years. The closest condition I've found is aerophagia, but this doesn't explain all the symtpoms.",
"I experience this too, and I've had it happen since I was 12 or so (28 now). It's annoying, and my mom used to make fun of me as a kid when it would happen. Anyway, I noticed /u/feralcatmeat mentioned that people who have this often can't burp voluntarily. That is true for me; I have done a true burp maybe six times in my life, and always involuntarily.\n\nI find it happens more when I drink soda, but not always. I also experience it when I eat certain foods. I had a bout of it really bad the other evening; I had eaten pizza and soda for lunch, and steak/potatoes for dinner. I don't know which of those caused it more, because it doesn't always happen when I eat certain foods.\n\nI've seen some correlation between this throat gurgle/\"burp\" thing and IBS (I also have a pretty bad issue with bloating throughout the day). I've cut down on a lot of foods I eat, although obviously I still eat \"bad\" foods like pizza/soda on occasion. You might try eating a low FODMAPs diet and seeing if that reduces your instances of the throat thing.",
"Can confirm I also had this as a child. I cannot voluntarily burp. It seems to be gas escaping or acid reflex like. It hasn't happened as often as it used to for years but it can be pretty loud in a quiet room."
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52oxip | what is dna sequencing? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/52oxip/eli5_what_is_dna_sequencing/ | {
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"DNA is made of a bunch of \"blocks\". There's not alot of blocks, so its the order of the blocks that determines what the DNA means. It's kind of like English where there's billions of words you can make, but not alot of letters, and it's the order of the letters that determines what the word sounds like and means. \n\n\nDNA sequencing is like hearing what the word/DNA is, and writing all the letters down in the correct order. Literally, its just physically looking at DNA somehow, and writing down the parts that make it up. ",
"DNA is made out of (deoxy)nucleotides. There are 4 nucleotides, adenine (A), thymine (T), cytosine (C) and guanine (G). \n\nTo multiply DNA, DNA is taken, combined with dNTP (the deoxy nucleotides), polymerase, primers (short segments of the DNA where the replication will start) and put in to a PCR (polymerse chain reaction) machine. The PCR machine cycles temperatures. The goal of this is to separate the two DNA strands, then cool down just enough so the primers can attach to the single strands and then the polymerase can add nucleotides and make two double stranded DNA segments. Repeat this as often as you want to get much of it.\n\nWhen you want to know the sequence of the DNA, you add ddNTPs (dideoxy nucleotides) which are coloured, for example A is blue, C is green, T is yellow and G is red. These can be attached to the DNA strand, but will terminate further nucleotide attachments. So for example you will get these four strands: *A*- A*C*- AC*G*- ACG*G*-. (The bolt letters are the ddNTPs, the - indicates the end of the strand)\n\nSo at this point you let the DNA run trough a gel. DNA is negatively charged, and will be attracted by the + pole. Longer pieces of DNA will get trough the gel slower than small segments. \n\nThey will run trough the gel and will fall down. If you get a special camera where it drips, you will see a colour every time. This way, it is possible to get the sequence of the DNA in the form of blue, green, red and red which you translate to the letters/bases. In this case ACGG.\n\nI may have made some mistakes at the detection method, or haven't explained it properly. But this is roughly how they sequence DNA."
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2thq41 | why do many top female tennis players make long squealing noises during play? | OK I will get this out of the way. The noises they make in many cases sound very sexual. I don't mean enticing or arousing, but a little unsettling as if I am hearing something I shouldn't.
If this the female equivalent of the grunt of effort male players sometimes makes that seems weirdly gendered. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2thq41/eli5_why_do_many_top_female_tennis_players_make/ | {
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"Women have higher register voices than men. Their \"grunts\" are going to be higher pitched as well, compared to the grunts from male athletes. It's not a mystery.",
"It can be a release of energy. They hold their breathe, tense up to get more power into the shot then all of the stored energy is released (exhaled). Sometimes with a grunt or a squeal. \n\nA lot of the time it's just habit and annoying though. ",
"Grunting(or squealing like you say) is one of the conflicting things in tennis. Some players say grunting should be banned and others say it helps them to play well because it was \"part of the rhythm\" for them during their play. \n\nThere is no definite answer for this question because its highly subjective. ",
"Studies suggest that it is part of the reason as to why they are at the top. They indicate that a player who grunts make their opponents delay their return of the ball by a decent margin. ",
"It's really just a way to control your breathing. The grunt is just making sure you exhale, and the pitch, tone and length are subject to each player, maybe just intimidation or TV appeal. ",
"So why don't quarterbacks and punters grunt loudly with each effort? I don't find the squeal sound to be sexual, but often, it's very masculine.",
"It's to mask the noise of the shot. In professional tennis, every millisecond counts, and if they don't grunt, a player with a trained ear can hear what kind of spin was applied to the ball, giving a better reaction time. Grunting leads the other player to have a worse reaction time.\n\nAnother reason is to probably generate more power, however that doesn't always make sense because they even grunt when hitting it softly near the net.",
"It's because when they use plyometric force they exhale rapidly (think boxers punching and exhaling). Others use it as a form of distraction."
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2rkoy2 | how exactly can a video file be compressed. what makes one 1080p video different from another apart from frame rate? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2rkoy2/eli5_how_exactly_can_a_video_file_be_compressed/ | {
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"Compression is taking a file, stripping out some of its elements and including instructions on how to fill them back in later. Compression algorithms can be lossy or lossless, where the former is possible to have some data lost and the latter creates a duplicate in the end. There's a lot of things that go into a video file that effect quality besides resolution and frame rate. There's the codec, which is the way it's compressed and decompressed, the bit rate, the chroma subsampling, whether its interlaced or progressive, etc."
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2nc7z2 | why do comercial planes only calculate exactly how much fuel they add in instead of just filling it all the way up? | I thought of this as I was reading about the Gimli Glider. This would'nt have occured if they filled it all the way up. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2nc7z2/eli5why_do_comercial_planes_only_calculate/ | {
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"To carry anything you dont need is a waste. The extra weight of the fuel means that you will burn more fuel just to transport it. The math is tight, but they save something...\n\nEDIT: Also, the less fuel you have on landing, when crashes are more likely to happen, the less likely that you have a magnificent fireball that kills everyone.",
"Extra fuel means extra weight, which results in more fuel burned. You've heard the phrase \"time is money\"? With airlines it's \"weight is money.\"",
"Because fuel has weight and the heavier the airplane, the more fuel you need to spend to maintain an equivalent speed. \n\nIf you overfill the tank, you will use more fuel than if you only filled it up partially. ",
"Because you have to carry that fuel making your plane less efficient. It's like carrying a backpack of canned food for a afternoon hike. If you are only going to need enough for one meal then why carry the weight ",
"Extra fuel is extra weight, which means extra fuel burned and extra money, which others have already said. Reducing weight is also a safety feature, a heavier aircraft requires a longer runway, faster takeoff, faster landing, and speed on the ground can be dangerous.\n\nThey don't calculate \"exactly\" the fuel, they calculate precisely, and then add a hefty safety margin. \nThe [Gimli Glider](_URL_0_)'s problem was that they calculated incorrectly. If you calculate incorrectly, gravity will have it's way with you. An airplane filled up to the brim before launch will still run out of gas if you incorrectly calculate how far it will go. "
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1y6rpy | why does china defend north korea so often at the international level? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1y6rpy/why_does_china_defend_north_korea_so_often_at_the/ | {
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"1. North Korea is already a huge humanitarian crisis, but collapse of the regime means that a huge portion of that becomes China's problem more or less immediately. Millions of North Koreans would flee into Northeastern China, which already has a large population of ethnically Korean citizens. Actually keeping these people alive after living their entire lives in the DPRK would be enormously expensive and a logistical nightmare.\n\n2. China likes having North Korea as a buffer state. Regardless of who would take over the area that's currently North Korea in the event of a collapse, China likely winds up with a US-allied country on its border, if South Korea would reunited with the North (which would cost South Korea trillions and take a very, very long time; the Reunification of Germany was a cakewalk compared to the situation in the Korean Peninsula). It would rather that didn't happen. \n\nThey know how bad things are in the DPRK, but by nominally supporting the Kim regime, everything is contained, from China's perspective. The status quo is the least bad option, in China's view.",
"As I understand it, the main reason China backs up North Korea is because they want a buffer state. They are fairly paranoid (as is Russia) and would rather have Crazy North Korea protecting them than nothing at all. Although lately China has become more and more irritated with North Korea's actions, I wouldn't be surprised if they decided it's not worth it anymore and denounced North Korea as an official ally. ",
"While China has been harder and harder on North Korea in recent years... They continue to support North Korea because they won't completely abandon their communist routes. North Korea is their ally for very similar reasons, it represents communism, and a lot of what China still likes to pretend it is. Just as China still refers to their economy as Socialism with \"Chinese Characteristics\" refusing to refer to themselves as the nearly full-blown capitalist state they really are, they hold onto the communist bits. And thus they hold onto the relations with the DPRK.\n\nAlso... With the U.S having so much influence in the region China likes to balance the power dynamic by holding what allies they can. ",
"China defended the Khmer Rouge until the bitter end, even when the KR controlled only a very small area in north Cambodia, and even after KR atrocities were fully exposed to the world. China's foreign policy is pure, utterly selfish power politics, ideals and morality are not part of the picture. China does not want a united Korean peninsula, it fears it would ally itself with the west. A perpetual dysfunctional basket case in the north serves to prevent unification. The attitude is China, first, last and always, the center of Heaven.",
"The enemy of my enemy is my friend.\n",
"From what I've been able to learn about the situation, is seems that there are two big reasons. The first is that as everyone has already stated, China likes having NK as a buffer state. Secondly, any humanitarian intervention into NK would create massive amounts of refugees, many of whom would spill into China and overwhelm city resources (think problems in Lebanon with Syrian refugees, or Jordan with Palestinian ones). It is in China's better interest to keep those refugees out and in NK.",
"China appreciates having a geographical and ideological buffer there. China is already bordered by about 15 countries, so it's nice to have an icy netherworld it doesn't have to worry about. Also, China sells all sorts of fake products (\"apple\", \"nike\", etc) to Pyongyang. ",
"because that's Chinas front yard",
"I think it is hard to sum up because it involves many different angles. This article tries to make it simple though. 6 little words.... Others disagree with this, but I could see how it makes sense. (I think the notion of buffer state is/should be included in this rational).\n\n_URL_0_",
"Let's not forget why NK feels a bit legitimized in their views. Per the cease fire agreement, allied forces from both sides had to withdraw from all the Korean peninsula. The communist allies did so. The US did not. Technically, the NK has a legitimate claim on who's the aggressor here - the US is violating the cease fire and thus blockading the course of a peace agreement. Of course its not that simple, nor could NK be trusted not to invade SK once the US pulled out, but still....",
"Can i ask same question for USA and Israel ?",
"China doesn't like the possibility of a US allied state right underneath them, not mentioning the fact that they get cheap natural resources from the North, which has been somewhat of a contested issue under the new Kim regime. It may be a massive headache for them at times but it comes down to money and politics here.",
"China also has a strong stated ethos of not interfering in the internal affairs of sovereign states. It claims the right to manage its own internal affairs and confers this right on other states. This gives the Beijing leadership cover to only contain the DPRK. You may ask about Tibet, Taiwan and it's South China Sea disputes (among a few others). China has its own perception of what constitutes its domestic sphere.",
"North Korea has one of the largest, if not the largest, deposits of rare earth elements in the world. These minerals are not only used in televisions and mobile devices, but missiles and advanced defense systems as well. Some estimate that there is $6 Trillion worth in North Korea. \n\nWith China already having a monopoly on rare earth elements, producing around 95% of the current supply, and their trade relationship with the DPRK, this creates an economic boon for China. It also aids the DPRK, because they don't have the infrastructure to mine for REEs, as they are very costly to extract.\n\nChina's monopoly of REE's is in fact considered a national security issue by the Worldwide Threat Assessment. Imagine if they begin to mine for them in the DPRK.\n\nI didn't even mention the amount of other minerals in North Korea.\n\nSources: _URL_1_\n\n_URL_0_",
"Because North Korea is best Korea ",
"The same reason we wouldn't let North Korea invade Mexico.",
"One of the big problems is that if there were no North Korea we (western countries) would view China similarly to how we view North Korea. We would start cracking down on Human Rights violations and such. Instability in the region works towards China's goals and redirects attention off them.",
"China is much less likely to defend north Korea today than it was 5 years ago. Also, if you check out some wikileaks diplomatic cables, it shows that Chinese officials have tacitly approved the possibility of a future Korean peninsula run by the southern regime. They realize that their future is with economic cooperation between the South and the US, not through propping up the north.\n\nAt the same time, China is threatened by the US military presence in Korea and the whole asia-pacific. Korean reunification means that the US occupied south will then occupy the north. The absolute LAST thing that China wants is US troops on its borders. The result of this is that China's biggest interest is in preserving a status quo by calling for stability. This doesn't mean that China will always come to North Korean defense (Look at China's response to the most recent missile crisis to see what I mean).",
"I doubt the Chinese government feels the need for a 'buffer state', as some people in this thread have claimed. That's a very antiquated view.\n\nNorth Korea has been a significant destabilising force in the region. The United States and its allies use a lot of resources managing the situation - resources that might otherwise be used in ways that are not well aligned with Chinese interests.\n\nThe Chinese government is happy for this situation to continue, as long as it does not become expensive for China, vis-à-vis a humanitarian crisis within Chinese borders, a conflict that causes significant economic disruption and so on.\n\nIn short, I think the proximity of North Korea to China informs China's stabilising influence on the ongoing conflict, but not their destabilising influence, which I feel is a deliberate attempt to weaken competing powers.",
"China is your house, South Korea is a house that likes to blast really loud music at all hours of the night. \n\nYou don't much fancy South Korea but luckily they're two houses away. \n\nNorth Korea is the house between you and the noisy house, whenever your neighbor gets into a little bit of trouble the noisy house tries and buys their house and get closer to you with their loud music. So rather than live next to the loud music house you help your neighbor stay afloat. \n\nHowever sometimes your neighbor also plays loud music, parks on your lawn, or lets their dog poop on your grass. However when you ask them to stop they usually do, unlike the noisy house two houses down. So while you don't always like your neighbor they're much better than the noisy house and the only thing stopping the noisy house from being right next to you. ",
"One thing that I haven't seen mentioned here is that the old guard within the Chinese army still puts a lot of value into the \"Blood Alliance\" that has existed between the two countries for over 70 years. \n\nMao and the oldest Kim really helped each other out during the dark days of the 1930's and 40's. A few highlights include North Korean brigades being present during the last battles against Chang Kai-shek's KMT forces on the mainland before they were driven to what is now Taiwan. China sent over a million troops into North Korea during the Korean war. \n",
"I'd always considered North Korea as a buffer state for China. Both South Korea and Japan have more ties to the United States than they do to China, so China keeps North Korea around to ensure that no US-loyal state has direct borders with them in East Asia. ",
"I have a good friend who is Chinese and he described the situation to me as such. North Korea is an international problem. It is a humanitarian crisis with nuclear weapons. Although NK has irritated the Chinese more than usual recently, they have historically been of value because they offer the Chinese additional leverage in international negotiations, in return for support of the regime (the aid mostly covers: infrastructure, resource extraction, humanitarian aid and military cooperation). If anyone (particularly the United States) wants to deal with the North Koreans, they have to go through China to do it. The North Koreans are also willing to do things on behalf of the Chinese government, they could not do themselves. The only concrete action i can think of at the moment is antagonizing the United States, although there is surely more. China cannot openly antagonize the United States, it would be a political and economic catastrophe. But, if the North Koreans do it, China is able to assert plausible deniability. While at the same time, the U.S. is pressured to take action and the White House has to work with the Chinese in order to do it. \n\nThe relationship has become slightly more tenuous recently because NK is losing some of its value for the Chinese. The Chinese economy is growing, they are becoming a more significant international economic power. Their inherent leverage is increasing as a result of strengthening economic ties with the rest of the world. Simultaneously, the humanitarian crisis is effecting China's reputation. However, the military alliance runs deep. It is my belief that the Chinese will advocate for reform if national destabilization becomes an issue. The Chinese have too much to lose. (note infrastructure, military and resource extraction). ",
"Follow up question: Why does the US defend Israel so often at the international stage? ",
"I could answer that by asking \"Why does US defend Israel so often at the international level\"?\n\nEvery country has their interests, that's the correct answer.",
"North Korea was made in China. ",
"North Korea acts as a buffer zone between China and South Korea. If the Korean peninsula was to unify, it would only bring the US troops/Western troops stationed in South Korea that much closer to the norther Chinese border and closer to Bejing",
"Surprised nobody has mentioned this yet, but the Kim Jongs backed China's current political party's rise to power during the communist uprising. This was the main reason that China started backing North Korea in the first place during the Korean War, and has continued ever since. The buffer state thing is true as well, although the United States was very successful in building up South Korea. It seems the US deserves to have a say in the future of North Korea as well.",
"I've come to this coversation a bit late, but I hope I can provide another explanation.\n\nIt's already been mentioned that China \"defends\" North Korea to maintain a buffer state against US backed South Korea, and to avoid a potential influx of North Korean refugees should war break out.\n\nHowever, there is one other important reason that I don't think has been mentioned yet. I've been told this by Chinese friends/colleagues (I studied and now work in Beijing) when I asked this question before.\n\nBasically, the Communist Party of China owes a lot to North Korea. In the 1920s and 1930s when the Chinese Communists were getting off the ground, they received a large amount of support and assistance from their compatriots in North Korea. When China was fighting against the Japanese, the North Koreans provided money and arms. When the Communists fought the Nationalists in the Chinese Civil War, North Korea again backed the Communists.\n\nMao Zedong and the Chinese Communist Party owed a lot to the support of North Korea in founding the People's Republic of China. To this day they still want to be seen as honouring this, and \"pay back\" the North Korean's generosity and support.\n\nHowever, given that Kim Jong-Un is still as despotic as his predecessors and is constantly branded evil by the rest of the world, China is distancing itself from North Korea, although still has to maintain the appearance of \"solidarity\" or \"defence\" or \"support\".\n\nI hope that answers the question from a different perspective.",
"Who else are thy going to support? Tibet?",
"Because North Korea Is Best Korea!\n\n And heres your new awesome wallpaper:\n_URL_0_",
"Most Asian states fear China because of its massive growth and dominance within the region, thus they are more aligned with the US. This explains US military presence in the region being more accepted. With this China doesn't have very many allies, especially in Asia. Ideally China would like North Korea to open its markets more with China but North Korea acts in a relatively rouge manner in the international arena. The US also does not have formal diplomatic relations with North Korea. This allows China to act as a third party during diplomatic negotiations. China uses this in order to show itself as a player in world affairs and offer greater influence in Asia\n\nTL:DR China doesn't have many friends in Asia and is competing with US influence in the area",
"China also defends North Korea as a way of making sure the balance of the international system doesn't become upset. If North Korea were a completely rogue state then its leadership's actions would be even more unpredictable and uncontainable. Something not reported widely in American media is the amount of behind the scenes negotiating Beijing does on behalf of the U.S. to ensure we don't end up in WW3. This helps the WTO and UN as well. \n\nEdit: Added the final sentence to veer away from my opinion and drive the logic of the argument to its conclusion. ",
"In my opinion it is starting to happen, north korea is nothing but a front that the chinese have kept for a while now.But the things are changing for good since the western media if giving more attention and keeps on asking the North Koreans to do something funny every now and then. If only they had Oil in their country the western democracies would become more interested in their motives to provide freedom to north koreans,sadly they only have people living in worst imaginable conditions which doesn't matter at all.",
"\"China to this day views NK like some famous movie star might view an awkward retarded brother who has a habit of masturbating in public and ruining famous older brother's PR. Sure, you can slap him around for doing it but that'll just draw more attention and get you in trouble for child abuse. Your only choice is to sit there and enjoy your prosperity and fame while accepting the fact that your awkward brother occasionally jizzes on your leg.\"\n\n_URL_0_",
"China likes to use North Kore as a buffer state. They didn't like the idea of having the U.S. and its allies close to their borders because that's the reason they intervened in the Korean War in the first place when U.S. and UN forces were closer to their border.",
"Ok, i'll try it ELI5 style: \n\nRemember the Smiths, our neighbors, two houses down? Well, we don't like them a lot now, do we? They have very powerful friends. Now they would love to buy out our neighbors next door, the Kims. \n\nWe don't like the Kims, either, but you know what, they don't have no friends at all, so they cannot harm us. They even depend on us, when we let some food on their doors at Thanksgiving. Now we really want to keep the Kims between us and the Smiths, so the Smiths can't get closer to us...\n\n\nWe are China, the Kims are the DPRK, and the Smiths are South Korea, which, in China's eyes, are basically helping the USA have influence in the region.\n",
"All of the attention North Korea gets for human rights abuses is attention China would be getting if North Korea didn't exist. North Korea is the human rights lightning rod for Asia.",
"Historically they've supported the \"Communist\" North Korea. Also, China really doesn't want a million North Korean refugees running into China, which is exactly what would happen. China isn't really happy with North Korea at this point, but has to support it just to keep the area stabilized.",
"Its a very similar relationship (minus a bit of freedom) to America's with Israel. ",
"China doesn't support North Korea - they often chide them. They do not oppose North Korea, though, which is quite different from the rest of the world's point of view - and very useful, as it means we have an ally who North Korea will listen to.",
"I always assume it has something to do with north Korea's massive military displays and their proximity to China's borders.",
"My opinion on China's support of North Korea, is simply to fund a puppet state. While Kim almost always acts without thinking, and without asking the CPC if he can do whatever. But China continues supporting them, even if the DPRK threatens is neighbors, or even America. Why? I think (like I said earlier) it is a puppet state in that they want Kim Jong Un to be unpredictable, and bringing attention to the region. On the news, whenever China does something rather big such as testing the DF-21 (anti-carrier missile which can probably change the balance of power in 20 minutes), there is little to no coverage on it. Back to the subject; China sees North Korea as a distraction for the West, and I think for an even bigger distraction for the United States, so they cannot help Taiwan as much as they could. Thee are probably lots of reasons, but I believe its they are looking for a distraction to the West.",
"I can highly recommend this book that gives a very good insight into the daily life of ordinary people living in North Korea. \n\n_URL_0_\n",
"Because they're commie, commie, commie, compatriots.",
"They are the crazy neighbors you watch over the fence. But they havent let their dog shit on your lawn, and they are better than the idiots you do not know. \n\nPlus, once a while you can go over and screw their wife.",
"Very plainly: communists gotta stick together. Not necessarily practically but for political solidarity. (Though Cuba and Russia have had a few collaborations that are more concrete, though whether useful in the long run is undetermined, since the partnership is not really continuing since one, and arguably both, are no longer communist.)",
"It's called Finlandization. North Korea is basically China's little brother. China also was on the DPRK's side during the Korean War. The Chinese call it \"The War to Resist America and Aid Korea\". NK also is completely economically dependent on China. So the Chinese can do whatever they want with NK. ",
"a variety of reasons\n\n1. if north korea collapsed, China would have American soldiers on its doorstep\n\n2. historically, Korea was a much larger nation, covering large parts of China heading deep into Manchuria, now an important strategic part of China. If North Korea were to collapse and unify with the South, then China would find itself with a very advanced, and militarised, and US backed neighbour who might decide that they want territory back.\n\n",
"North Korea is to China as Israel to the USA. ",
"\"Everyone wants the concentration camps shut down and some measure of freedom for ordinary North Koreans. No one is willing to risk the population of metropolitan Seoul to do it.\" [link](_URL_0_)\n",
"First thing, it should be understood that China's support of North Korea is waning very rapidly. \n\nI think the biggest reason is shown by the similarity of North Korea to China in the not so distant past. They know that when the regime falls huge atrocities will be uncovered, and that will reflect badly on China as well, because China also has some dark secrets they have never dealt with.\n\nAlso, its clear that they feel somewhat threatened by the prospect of a reunited Korea - South Korea is increasingly a wealthy country, which is aligned with the US. However, its even worse if China stands in the way of Korea reuniting, and I think that China's new leadership, which is younger, sees that. Many Americans don't realize that the Chinese leadership recently changed and this seems to mean some very clear shifts on a number of issues. Its possible that North Korea is one of them. In any case, I think China has **much to lose and nothing to gain** from supporting the despotic NK regime and a lot to gain by helping ease the Kim dynasty out of power.",
"China also gets leverage on the world stage as the only country that can control North Korea (in a relative sense). If you are the only member of your family who can get the baby to stop crying, you can use that power to get favors from the rest of the family.",
"For the same reason why the US props up puppet governments in a lot of countries. It just so happens that NK has batshit crazy leadership instead of the standard corruption.",
"Dear Everybody in this Thread: Israel is *not* fucking relevant to OP's question. It's an interesting question, one that deserves its own thread and robust discussion, but *it's not fucking relevant here*."
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[],
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"http://www.washingtonpost.com/blogs/worldviews/wp/2013/02/12/why-china-still-supports-north-korea-in-six-little-words/"
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[],
[],
[],
[],
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"http://www.mining.com/largest-known-rare-earth-deposit-discovered-in-north-korea-86139/",
"http://www.usnews.com/news/blogs/at-the-edge/2013/04/02/chinas-continuing-monopoly-over-rare-earth-minerals"
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"http://www.amazon.com/Nothing-Envy-Ordinary-Lives-North/dp/0385523912/ref=sr_1_1?ie=UTF8&qid=1392728799&sr=8-1&keywords=barbara+demick"
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dicawg | during a rocket launch, why is there ice falling of the rocket? | Hey there,
so in movies like Apollo 13, when the rocket launches it is shown that ice shards (or something else?) falls off. Why is that?
Here's a youtube link to said scene. The ice shards are visible at 05:11
[_URL_0_](_URL_0_) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dicawg/eli5_during_a_rocket_launch_why_is_there_ice/ | {
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"There's no air in space so rockets must bring their own oxidizing agents.\n\nIn the Saturn V rocket this is liquid oxygen, which is -183C and pumped in shortly before launch. The lines are insulated, but that's still cold as fug and things freeze up.",
"Liquid Oxygen is used to power the rocket. Liquid Oxygen is about -300 degrees. They insulate the heck out of the tank but it still gets cold enough to cause humidity to freeze to the side of the rocket. The vibrations from the launch shake it loose.",
"The propellant system uses very cold liquid hydrogen and liquid oxygen. As you get condensation, the cold stuff causes it to turn to ice and then during launch it falls off.",
"Because of the liquid oxygen/hydrogen stored in the rocket, ice forms on the metal surface. At ignition, the ice is shaken off by the rocket blast and falls away in a few seconds.",
"The fuel was liquid hydrogen and oxygen. Tanks were continually topped up while on the launch pad. The extremely cold temps needed to keep the fuel and oxidizer liquid caused condensation to form on the rocket.\n\nI believe that the tanks were partially kept cold by controlled venting of the contents, hence the need to top them up.\n\nFlorida is \"somewhat\" humid, so the extremely cold temps used caused significant ice formation purely from condensation from the atmosphere.\n\nOxygen boils at -219 C, Hydrogen at -252 C.",
"No one has mentioned that on lift off a massive amount of liquid oxygen and hydrogen is being released. This transition from high pressure to low pressure creates even colder temperatures than the liquid gasses did just sitting there."
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tjlc2 | what causes rigor mortis? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/tjlc2/eli5_what_causes_rigor_mortis/ | {
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"Muscles actualy need work to relax/extend by pumping calcium ions out of the cells and \"rewinding\" the fibers to default postition.\nLetting calcium ions in the cell again then in fact triggers the fibers to spring into flexed position.\n\nAfter the cells die, they can't keep the ions outside anymore and they eventually get inside and flex the muscles. It is, ofc uncoordinated and doesn't work properly but it sufficiently locks the muscles in place. \n\nAs these protein muscle fibers decompose the rigor subdues."
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7rdd4f | how does a javelin rocket launcher track moving targets. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7rdd4f/eli5_how_does_a_javelin_rocket_launcher_track/ | {
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" > How does a Javelin Rocket launcher track moving targets.\n\nIt has an automatic infrared guidance system which locks on to a heat signature and will adjust the two rear fins in order to steer it toward the target.",
"I program and develop guidance and control algorithms for a living. The answer is really complicated, but I will do my best to explain how this works.\n\nBasically, these are called tracking algorithms. They use a marker as a source, such as a laser dot or heat signature, and measure their distance and velocity relative to this marker. A mathematical formula calculates a number based on this distance which is converted into a physical signal that tells the fins and thruster how to move. The fins and thruster moving correspond to the physical movement of the missile. \n\nThis is formulated using control theory - a highly interdiciplinary subject."
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acdeni | do electrons move anywhere down the chain in ac? | I've got the idea of the current changing direction at 60 Hz. Do the electrons GO forward?
At my wall socket: on each iteration of the direction change do a bunch of electrons get dumped out-- or is it a forward flow of electrons despite the forward/back oscillation?
Any help is appreciated! I don't get how anything goes forward or how electrons are delivered to the outlet. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/acdeni/eli5_do_electrons_move_anywhere_down_the_chain_in/ | {
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"The electrons are in the copper wire. When the current pushes forward it pushes electrons through the circuit. When it reverse direction it pulls them back in the other direction. \n\nDoes that answer your question? "
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aqycf4 | modern monetary theory | I'm trying to read up on it, but it is so laden with jargon that I can't get through more than a paragraph without having to do additional research. All the sites I've found that attempt to explain it seem to assume I must be an economist already.
I would love an explanation using layman's terms please. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/aqycf4/eli5_modern_monetary_theory/ | {
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"I first heard about on the Planet Money podcast, it starts with a 10 year old asking the question and they explain it in pretty simple terms.\n\n_URL_0_",
"MMT theory reverses how most people think about government economics. Most people visualize the government collecting money through taxes, then spending that money to get something done. MMT says that because we have a fiat currency, the government can just create money, spend it however it wants, and taxes are just a way to remove excess money afterwards to prevent inflation.\n\nThe conclusion they draw is that arguments about how the government pays for anything are irrelevant, because the government can literally print as much money as it wants. The government just has to make sure that the economy has spare capacity to use that money and inflation won’t be a problem.\n\nExample: if a car factory can make 1000 cars a month, but is only getting 700 orders a month, the government can pay them to make 300 additional cars without causing inflation. If they paid for 500 cars a month, then the extra 200 would Cassie inflation because demand outstrips supply, raising prices."
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4g10ri | how is code organized and added on to for large video games? (e.g. halo, battlefield, etc.) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4g10ri/eli5_how_is_code_organized_and_added_on_to_for/ | {
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"By any well run company into many different parts. The idea is that everything should be broken down into the simplest methods that they can be broken down into. Easy to test and easy to build on. \n\nFor a simple game it will look sort of like this\n_URL_0_\n\nFor a complicated game imagine the same but a lot more boxes. ",
"In many software projects, code is somewhat stored in the same way. I will use game examples here, but generally you have code that does a each part of the basic system stuff, code that adds onto the basic features, and then code to tie the whole project together. In all the large software projects I've worked on, this is more or less the same, regardless of language.\n\nFirst I'm going to talk about general code structure.\n\nIn games, there will be some files that handle each main part of the game, like movement, items, players, and so on. Many object oriented languages like C++ will have these files store properties of each part of the game. \n\nThe players file may keep track of the user's stats, the position that the user is on, and which map the player is in. Is stats too broad of a topic? Maybe there's a file that breaks down stats to smaller bits. There might be a file to keep track of a user's speed, health, power. Then the players file will reference the stats file to get the user's stats. This way, the key files won't be too large. Inside the player file, it might also keep track of other things, like the user's items, or abilities the players holds. Each of those can be handled in another file.\n\nThen let's say there's a file used for item storage. There will have to be a way to retrieve it from a database of some sort, or a save file. An items file may have a database call to grab all items per user, and then create structures to hold the items in. Then the player file talked about earlier may have a reference to the item storage file. \n\nLet's think about what enemies the player may face. Maybe there's a large wolf, mice, enemies from mario, your evil next door neighbor, and maybe yourself. What do they all have in common? They're all your enemies. We can start out by creating a file that holds information about enemies in general. Then like a tree, make other files that have the same properties as the enemy, but have slightly different features. Maybe wolves have 2 more attacks than the mouse. The idea is to have a general file, and then files that do slightly different, but similar things.\n\nAll of you have to go somewhere, so there might be a map file, to hold details about maps in general: your school, the woods, the player's secret hideout. It might hold information about what enemies are on the map and where they are located. It might hold information about the map in general like the name, the location of the map.\n\nSo far, we have the player with the player's skills/items, enemies, and where they are located. However, since nothing was created about movement, maybe they can't even move yet. There has to be some engine that handles movement, handles if an attack will connect with an enemy, etc. This is where the math comes in (as well as rendering the images of the game). There has to be calculations done for all of this.\n\nAs for game data, a lot of people store the data in some sort of easy to read format. This way the computer will load up the data when the game starts, and then it will know that a wolf has 40 hp, and a mouse has 4 hp. Sometimes people choose to load all data at once, but others choose to load data slowly. I imagine common data like skills, map data to be stored/loaded in a similar fashion.\n\nI can probably go on about this for days, but let's talk about the next topic...\n\nUsually code should be written to be modular and expandable. Anything coded should handle everything that's previously coded, and then everything in the future. Code is also laid out to do this, which is why it can get complex fast to think about a general case. I can't make code just work for 1 type of player name, it has to work for everything. All general enemies should be coded so that any future enemies are easy to add and remove.\n\nNow, let's say we have a well done skill file coded and you want to add a new skill to your game. You will first update the data files that hold skill information. Type in some numbers, some properties about the skill, whatever the skill file holds. Then if you are lucky, your well coded skill file will already handle everything. \n\nSometimes, a new feature is too new, and requires additional coding. Let's say you throw a dagger at an enemy. The dagger is magical and splits into 2 and hits 2 bad guys. However, all your previous skills could only hit one. Now you will have to add additional code to handle this. You may want to code it so that in the future your attacks can hit N enemies, so you don't have to keep adding code to handle 2, 3, 4, and more enemies in the future. Of course, if this can be done, that would be optimal. It's not always this easy though. \n\nSometimes code can't be easily modified. Maybe the system depends on some values calculated by the first attack, and then the second attack from the magic dagger won't work. Then it will require additional recoding to change how the first attack worked to not make the game depend on stuff from the first attack. What if another feature of the game depends on the other feature too? This is why coding can get messy and structure of the code and design matters. A lot of time should be put into figuring out possible cases when new features are added to make the scale better with time. It's also why sometimes games start out really good and then slowly gather more bugs. Adding onto games is not always easy.",
"The core concept is a thing called Object Oriented Programming, or OOP for short. The idea is you design the code to work independently for each \"object\". An object can be a player, an enemy, an item etc...\n\nFor example, all enemies will likely need to know how to move and attack, so the code for that is made as one \"object\". Then for each different type of enemy, it only has it's own unique code added to it's \"object\" and references the move/attack object for that code. This way, if you want to update the movement for everything, you only have to change it in one place.",
"When you need to add or edit code, you can find it because the code is broken down into its smallest pieces. Think of a game's code like shoeboxes in a closet. The closet is the game, and the shoeboxes, the code, are contained inside. The shoeboxes are organized in a specific way (like color or occasion). You can add new shoeboxes into their designated areas or you can change what shoes are in what box; maybe you accidentally put 3 shoes in one box and that created a problem because the boxes on top were leaning to one side. You find the problem is that box, so you investigate, remove a shoe, put it back, and see that the boxes on top are now standing straight: problem solved. That's basically how code works. Code is broken up and contained in their own boxes, but depend on other parts of code to work right. You can go into boxes separately to fix things without destroying everything, you'd only affect the parts that depend on that piece of code."
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pofg6 | why do some people have round eyes (white people, some africans, middle easterns) while others have slanted eyes (east asians, other africans, native americas). | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/pofg6/eli5_why_do_some_people_have_round_eyes_white/ | {
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"The structure that makes eyes appear \"slanted\" is the [epicanthic fold](_URL_0_). There is no particular \"reason\" that can answer your question of \"why,\" except that this was how this trait happened to develop in specific groups of population."
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3enheg | how is it that reddit was never able to turn a profit since it was founded? | From my basic understanding, an internet company like imgur would find it very difficult to turn a profit because they have to host so many images and that eats up a ton of bandwidth, but since Reddit doesn't actually host any of the user-submitted content, what are the expenses that have made Reddit unprofitable year after year?
Also, I think they accepted $50mm in capital not too long ago. What will that be used for and how will that help make Reddit profitable? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3enheg/eli5_how_is_it_that_reddit_was_never_able_to_turn/ | {
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"Disclaimer: I don't have any special insight into Reddit's inner workings, just Google and a business degree.\n\n_URL_0_\n\nWhile imgur might handle all of Reddit's images, Reddit itself still needs to maintain server capacity for 7.55 Billion page views per month, as well as records of tens of thousands of subreddits, millions of users, etc... I'm no network engineer, but I think I can safely say that that isn't cheap.\n\nAdditionally, Reddit has over 40 employees that need to be recruited, trained, and paid. It wouldn't surprise me if the payroll and HR budget was upwards of $5 million a year, not including executive pay.\n\nIn the age of Internet start ups, 10 years without an operating profit isn't particularly alarming. Twitter for example, is only 9 years old, and might make its first profit in 2015 or 2016. Reddit faces the same kinds of dilemmas. They can't directly monetize users, because no ones going to pay a monthly fee, and too many ads will drive down user counts and ad revenues.\n\nAs to what the recent round of capital will actually be used for, its anyone's guess. Expanding staff, improving server capacity, etc... ",
"While I have no specific insight as to Reddit itself as a business, it is worth noting that \"turning a profit\" is often not the goal of a corporation. When a company is profitable, (brings in more money than it spends on costs) the people who benifit are the shareholders, and the government who collects tax on those profits. When a corporation is profitable, they must distribute those profits, either in employee bonus pay, or as dividends for the shareholders. However, company can adjust their costs every year in order to avoid being profitable. So long as the shareholders don't revolt and elect a new board of directors, this can continue, and is often in the best interest of the corporation, and the shareholders. So long as all earnings are reinvested in the company, the value of the company grows quickly. This often provides a better long term return on investment than profit dividends.",
"So, if reddit goes the way of Digg and MySpace within the next year, will everyone involved have wasted their time and money? I'm thinking the employees got paid anyways, but were they being paid off of loans or something? Will there be an angry investor who just lost several million dollars? "
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4de0yu | why does flash memory have a limited number of uses? and what happens when they run out? | Flash memory is supposed to have a limited number of write/erase cycles. What happens when they're all used up? Does its capacity start decreasing or does it stop working altogether?
Suppose I have an 8GB flash drive, and I transfer 4GB of music into it. Did I use up hundreds of cycles (one for each file) or just half a cycle? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4de0yu/eli5_why_does_flash_memory_have_a_limited_number/ | {
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"You used up exactly half a cycle. A cycle is basically considered as one write to a cell. Technically because you could write over the same cells multiple times without writing over other ones it doesn't work exactly like that but it is close enough.\n\nEach time you write to an individual cell (there can be multiple bits per cell IE MLC flash) the cell wears out a bit. Physically a layer of flash 'captures' electrons going into the cell to record a state. The trick with flash is that the charge is unable to ever leave the circuit. in order to ensure this happens the cell is nearly electrically isolated. This means that that writing the cell takes a large amount of power, and a high voltage and temperature. Reading the cell is physically harmless.\n\nNow what happens in particular as a cell wears out it gets a few failure characteristics. A write to a cell would have a chance of not working. Writing a '1' to a cell might actually leave the cell in a '0' state. The other failure mode is data loss. A failed cell can have conduction to other parts of the chip and loose its energy internally over time. These two errors have different effects but ultimately are the end of life for a flash chip. Now one thing to keep in mind is that the quoted life cycle is basically a guarantee. You won't realistically see any corruption until after you have hit that limit on at least one cell. In some Cases you can double or triple the value for a cell with no problems.\n\nThis isn't the end of the story. All electronics are manufactured with a certain percentage of pieces not working. It is not feasible to ensure that every transistor works on a design of 2 billion transistors in a pinky fingernail area. For some devices this means that you choose an operating range that all components work correctly, for others you include redundant parts and choose the ones that work at production - in flash it's a little weirder, they are often connected to chips that manage whether memory is working or not on the fly.\n\nSo for an average USB key the primary motivation is cost. The easiest way to minimize cost while maximizing size is called over-provisioning. A typical USB key or memory card is manufactured with two parts on the chip - A small CPU that manages the flash memory and access to it, and the memory itself.\n\nBefore shipping the devices are run and figure out what pieces of the flash memory are working by testing it. The chip then keeps that and uses it to determine how it will allocate your data. At the same time it uses a process called 'wear leveling'. It can use wear leveling to help ensure that no individual cell gets worn out before the rest of the device. It also has a second defense against worn out cells - any excess working memory components are brought out when it finds a section of memory doesn't work as well as it should.\n\nTLDR cheap USB keys are miracles of engineering and you only used up one cycle.",
" > Suppose I have an 8GB flash drive, and I transfer 4GB of music into it. Did I use up hundreds of cycles (one for each file) or just half a cycle?\n\nYou used up **no** cycles. A flash cycle occurs when the flash storage is *erased*, typically to make room for new data after old data has been deleted. When you delete data on a flash drive, the data isn't actually deleted, it is just marked as deleted.\n\nIf you write 12GB to an 8GB flash drive (write 8, delete 8, and then write 4 more), approximately half of the flash chips in the drive will have experience *one* cycle, while the other half still would not have experienced a single cycle yet.\n\nWhen the drive is full, the flash chip (a flash drive has multiple chips) with the most deleted data will be erased: First all the non-deleted data is copied off of it, then the chip is \"flashed\", resetting the chip and allowing every bit to be writable again. Lastly, the non-deleted data is copied back to the chip. *This is one \"cycle\" for the chip*. Repeat until there is enough unwritten space on the drive.\n\nIt is easy to read from flash, and easy to write to unwritten flash, but it requires a large amount of power to reverse the writing process to restore the flash to an \"unwritten\" state. This reversal process is what \"wears out\" the flash chip. It can only be reset so many times before it becomes damaged.\n\n > What happens when they're all used up? Does its capacity start decreasing or does it stop working altogether?\n\nTypically it stops working reliably. Imagine bending a paperclip to form different letters, one after the other. It will work for a while, but after enough letters the paperclip will suddenly break when you're trying to bend it into the next letter. You could try to make parts of letters out of the remaining pieces of paperclip, but it's easier to just grab another paperclip from the box of paperclips."
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2zq3tg | why do certain violent groups like isis receive more western military attention than other groups like boko haram? | I really am ignorant about this but I'm looking for an answer that's more sophisticated than just "because oil". | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2zq3tg/eli5_why_do_certain_violent_groups_like_isis/ | {
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"ISIS is a major threat to the royal family of Saudi Arabia, who have been close strategic partners to the United States for a very long time. The upper class in Saudi Arabia lavishly enjoy many freedoms that are sacrilegious to the lower class, and the country is a breeding grounds for radical Islamist terrorists (15 of the 19 9/11 hijackers were Saudis, plus Osama bin Laden himself). An ISIS-backed popular uprising against the Saudi government is a very real risk and would be a major blow to the US's ability to make peace deals and trade agreements with much of the region.",
"Boko Haram is in Africa. Nobody wants to get involved in Africa because of what happened in Mogadishu and Vietnam. "
]
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1r7xis | why when i view a movie/game do i think "the graphics/special effects can't ever look better than this; this looks like real life!" yet when i watch the same scene a year later it looks super fake? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1r7xis/eli5_why_when_i_view_a_moviegame_do_i_think_the/ | {
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"text": [
"Because graphics always improve, so the \"best\" from 2007 is not as good as the \"best\" from 2013, and once you're used to 2013 FX then you can see the flaws in 2007 FX."
]
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[]
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|
||
8fytbv | why only certain people are kidney compatible | Mostly just why if someone needs a kidney only a few people can give it. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8fytbv/eli5_why_only_certain_people_are_kidney_compatible/ | {
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"You have to be a tissue match to donate any organ to someone. This just means that the cells in your body recognize and accept the new tissue cells, as opposed to treating them like a disease or infection that's gotten into the body. \n\nIf you're not a tissue match, the body could reject the donated organ and trigger an autoimmune response, which is basically just when the body attacks itself. These can be life threatening. ",
"Our bodies have strong defense mechanisms against anything unfamiliair that enters is.\nThis helps us against anything from bacteria to poisens. \n\nThe way this works is such: every cell in the body has certain markers (imagine puzzle pieces) that they recognise as friendly.\nAny cell that doesnt have the same markers is seen as hostile and is attacked by the body's defense.\n\nBecause there is a limmited number of different puzzle pieces, some people have the same combinations and can donate organs to eachother.\n\n\nVery simplified version but thats about it."
]
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2p3u1i | why are reservoir dams always curved towards the lake? | I guess it has to do with stability, but why exactly? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2p3u1i/eli5_why_are_reservoir_dams_always_curved_towards/ | {
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"The curve, much like a triangle or the supports under a bridge support the weight of the water pressing against the dam. try bending a stick and trying to press against the bend vs just holding the stick flat and pressing against it.",
"it's an arch laid on it's side, it gives it more structural stability",
"Imagine if it was blocks of material and it was fighting against gravity vertically rather than horizontally. Then you would have blocks or bricks which would need to be stuck together with grout or something to keep from falling down. Curve it into an arch instead and the blocks can hold together just by being pressed against the others. Turn it back down to horizontal againt the pressure of water and connect the blocks with more of the same and you have a dam. It uses the compression strength of the material rather than shear force to support the weight of the water.",
"with dams shaped the way they are, the anchor points are pushed into the sides of the canyon, so as long as the rock is solid, the dam stays strong. if it were the other way, the water would pull the dam away from the sides, which is much easier.\n\n"
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lrom9 | the photoelectric effect and photovoltaic cells | I'm trying to give a presentation on solar power and its uses, and I have pretty much no scientific background so understanding any of it is difficult. Any help would be much appreciated, as would sources, as I'll need to cite some. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/lrom9/elif_the_photoelectric_effect_and_photovoltaic/ | {
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"Photoelectric Effect: electrons are part of atoms. They're very, very small and move around the center of the atom, the nucleus. Because of the way electron energy works, it can be helpful to think of the electrons as being \"trapped\" in a well or other deep hole. They can move around inside the hole/well, but they don't have enough energy to jump out. Enter; light. Light is a form of energy. You're probably familiar with the idea of a photon: the smallest bit of light energy you can have. Photons carry energy in different amounts. The amount of energy depends on the color of the light (keep in mind that our eyes can only see some of the colors of light, things like radiowaves, microwaves, or infrared are invisible colors of light). If a photon runs into a trapped electron, it can pass it's energy to the electron. At this point, a few things can happen. If the photon was not carrying a lot f energy or if the electron was in a very deep hole, the electron will get excited, but won't be able to escape. Eventually the electron will calm down and shoot off a new photon. If the photon is carrying enough energy, then the electron can get so. Excited that it jumps RIGHT OUT of the well! Now the electron is free to shoot around for a bit until it recombines with another atom. There is a lot of interesting stuff with the photoelectric effect, but the important thing is that light can bounce electrons out of their atoms.\n\nPhotovoltaic cells: So take a material that exhibits the photoelectric effect and layer it between materials cleverly designed to make use of those bounced electrons. See, those free electrons are really just out for a little while. They get homesick pretty quick and need to go back to an atom. The layers of a photo voltaic force those poor electrons to leave the material they came from and travel a long way around to get back to an atom. While the electrons are going the log way, we can use their flow to power up electric devices. There are some technical inaccuracies with this explanation, but I think you get the idea.",
"Photoelectric Effect: electrons are part of atoms. They're very, very small and move around the center of the atom, the nucleus. Because of the way electron energy works, it can be helpful to think of the electrons as being \"trapped\" in a well or other deep hole. They can move around inside the hole/well, but they don't have enough energy to jump out. Enter; light. Light is a form of energy. You're probably familiar with the idea of a photon: the smallest bit of light energy you can have. Photons carry energy in different amounts. The amount of energy depends on the color of the light (keep in mind that our eyes can only see some of the colors of light, things like radiowaves, microwaves, or infrared are invisible colors of light). If a photon runs into a trapped electron, it can pass it's energy to the electron. At this point, a few things can happen. If the photon was not carrying a lot f energy or if the electron was in a very deep hole, the electron will get excited, but won't be able to escape. Eventually the electron will calm down and shoot off a new photon. If the photon is carrying enough energy, then the electron can get so. Excited that it jumps RIGHT OUT of the well! Now the electron is free to shoot around for a bit until it recombines with another atom. There is a lot of interesting stuff with the photoelectric effect, but the important thing is that light can bounce electrons out of their atoms.\n\nPhotovoltaic cells: So take a material that exhibits the photoelectric effect and layer it between materials cleverly designed to make use of those bounced electrons. See, those free electrons are really just out for a little while. They get homesick pretty quick and need to go back to an atom. The layers of a photo voltaic force those poor electrons to leave the material they came from and travel a long way around to get back to an atom. While the electrons are going the log way, we can use their flow to power up electric devices. There are some technical inaccuracies with this explanation, but I think you get the idea."
]
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2esber | what specifically happens when i get the "we took too long to make this page for you" error? | Thanks! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2esber/eli5_what_specifically_happens_when_i_get_the_we/ | {
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"The server is busy.\n\nReddit is essentially a series of servers, at least that's it's physical form, that each of us connects to. When the server space we are trying to access can't be accessed because of traffic, the overflow is sent to another area that replies with the \"Ow\" - Reddit page with alien."
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2x0pf1 | why don't game developers make games that gamers want? | My example would be Fallout 4 or half life 3 I see astronomical amounts of posts and other internet buzz asking if not begging Valve and Bethesda to create these titles and yet neither company even hints at the possibility. I guess the reason I'm wanting an explanation, would be that wouldn't creating these titles with all the buzz and hype make these companies filthy rich and superbly famous even more so than they already are? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2x0pf1/eli5why_dont_game_developers_make_games_that/ | {
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"What the internet says it wants and what will actually make money are very different things. Remmeber a while back everyone thought Snakes on a Plane was hilarious and it was all abuzz on the internet. Then the movie came out and it only made $15 million in its first week and barely 5 million the second. The internet is kind of an echo chamber so when something gets hyped it builds up a tonne of hype but that doesn't mean the public by and large is into somethign enough to spend money on it.",
"Because some companies are afraid they wont live up to the hype and rightly so. If HL3 came out people would spend decades comparing it to HL2 and some people will claim its terrible compared because they experienced it after the wonders of childhood. It is hard to do sequels without kicking yourself in the face as a developer, especially while still trying to innovate new ideas and mechanics.",
"Fallout 4 is under development. These things take time.\n\nIdeally, the company wants to wait until the last youtuber stops making videos about New Vegas and the last modder abandons 3 before releasing 4, in order to make sure that nobody is still tired of Fallout when 4 comes out.",
"You need to up your ante each time or your going to leave a sour taste in your audiences mouth. \n\nFallout 3 was made with the best technology of it's time. Releasing fallout 4 without sufficient tech advances would be a bit of a slap in the face as it wouldn't be a significant enough improvement, to counter this they released numerous DLCs as well as Fallout New Vegas and it's own set as a way of capturing the demand of \"more fallout\" without creating a sense of over-saturation or giving the audiences any impression that they'd be upping their game (no pun intended, could have rephrased to avoid the pun altogether, too lazy.).\n\nHalf Life 3 is in an awkward spot because of what a landmark series it is, not only is it a series that is intended to up the ante on it's predecessors within it's own series, it is also required to up the ante on the fps genre as a whole much like 1 and 2 did. This is going to require not only significant technological developments, but for Valve to be leading them.",
"Chances are both of those games are already in development. They just haven't been announced yet.",
"To them, they ARE making what gamers want. They're making money selling what they are now, and they are businesses. They aren't going to deviate from their cash cows (case in point- innumerable Assassins Creed and Call of Duty games).\n\nThese franchises, for better or worse, is where their big money comes in. Thus, there's not as much emphasis on other games. And face it, games are a big gamble. One stinker or one game that fails to perform can and has sunk companies.\n\nBasically, to us gamers as a whole, if we want more awesome games, we're gonna have to speak with our wallets. And unfortunately, most wallets are speaking to cookie cutter franchises and silly little throwaway apps and shovelware.",
"They would most likely have to build up hype and announcement. Imagine subtle hints towards Half-Life 3 everywhere that we've failed to notice. But there are slowly more and more. Eventually they're practically shovig it in your face without actually doing anything. And then, at E3, 1 year before the official announcement, they mention it. Barely. The next year they announce it with a whole segment dedicated only to it. They give it a release date of 1-2 years later. More time to build hype. Then they will release it, and after all these years of preparation it will actually live up to expectations. But what do I know? It's not like I'm involved in any of this.",
"Good studios spend a lot of time and money doing research on what games to develop. They care what games people will buy, not what games people on the internet say they want.\n\nFor example: I see a lot more hype and speculation about Fallout 4 than I do about Elder Scrolls 6. This is in spite of the fact that Skyrim made more than twice as much money as Fallout 3. So which one will make more money: the one with more internet hype, or the one that has a better track record? I have no idea, but I have no doubt Bethesda has spent considerable resources to predict the sales of either Fallout 4 or TES6, and are using that information in their decision process."
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303zzx | why does drinking water hurt my mouth ulcer? | You'd think it would be totally neutral, but it always stings a little as I drink it.
Couldn't find anything in Google so I'd thought y'all might help me out. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/303zzx/eli5_why_does_drinking_water_hurt_my_mouth_ulcer/ | {
"a_id": [
"cpoyip9"
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"score": [
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"text": [
"When I get mouth ulcers, I tend to drink lukewarm water and that doesn't hurt like a regular or cold water would do.\n\nIt also gives some soothing effect too."
]
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4alosa | what's the benefit of using a ceramic knife? | How's it different from using a metal knife? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4alosa/eli5whats_the_benefit_of_using_a_ceramic_knife/ | {
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"- Ceramic can't rust\n- Ceramic is lighter than steel\n- Ceramic is slightly harder, which means a slightly keener edge, retained for several times longer\n\n- _URL_0_",
"In principle, a ceramic knife, being much harder than a metal knife, starts out sharper and stays sharp much longer.\n\nIn *practice,* though, ceramic knives are very brittle and chip very easily. A metal knife is malleable and the metal edge gets \"smooshed down\" over time, but the edge of a ceramic knife chips away instead. This means ceramic knives can't be honed back into sharpness the way metal knives can (with a honing steel), but instead must be re-ground … and they can only be re-ground with specialized equipment, so your neighborhood knife guy probably can't help you. In the general case, ceramic knives must be sent back to the manufacturer to be re-ground … or even more generally, they're really just disposable."
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[
"https://en.wikipedia.org/wiki/Ceramic_knife"
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65e4ta | how does hemoglobin carry oxygen? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/65e4ta/eli5_how_does_hemoglobin_carry_oxygen/ | {
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"text": [
"dative bond between the iron ion in the haem group of the haemoglobin molecule and an electron pair from the O2 molecule",
"There is an iron atom in the hemoglobin at a point where it's grip on the oxygen atom (or one of the oxygens in CO2) can be influenced by a mechanical change in the shape of the hemoglobin molecule. [This wikipedia animation](_URL_0_ ) shows how it works."
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5kwc9a | why brains sometimes do the opposite of what you say or need to do | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5kwc9a/eli5_why_brains_sometimes_do_the_opposite_of_what/ | {
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"Saying \"I WILL bring\" to your brain is better than \"Don't forget to bring\". The brain seems to remember/listen to positivity more than the latter. Plus, the shorter the info, the better that it'll recall.\n\n* \"I will bring\"=3 words, 3 syllables.\n* \"Don't forget to bring\"=4 words, 5 syllables.\n\nIt may not work for all but it improved the memory of my friends after I told them to.\n\nI'd recommend a thing that I do. When I'm about to leave, I look back/behind to see and think if I missed a thing or two. If that doesn't work, you can make a list of what you should have in your bag before you leave. Have a good day.\n"
]
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2hexnc | why are we conditioned to hate things that are popular? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2hexnc/eli5_why_are_we_conditioned_to_hate_things_that/ | {
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"I can say from my experience why so it's my opinion only. I like to watch anime. When one popular anime comes out and everyone is like \"OMG THIS IS SO GOOD\" so after a while I give it a shot but it's not what I expected. They are from bad to normal nothing awesome or amazing, for example SAO or Naruto. There are a lot more better ones than those, but why do they get all this popularity? IDK. So what I'm trying to say is that there are a lot of things better than the popular stuff (which is bad or maybe average but not amazing) and that's why we hate popular stuff because it gets more attention than it deserves. Same with music.",
"If they are popular then we have higher expectations, so we are more likely to be dissapointed.",
"There's a theory that we want to do two specific things at the same time: 1) Be our own unique ourselves and 2) Be social, a part of a group. If you are too much of an individual, too specific, you lose out on friends. But if the group is too big, too common, you are no longer unique.\n\n(This is [Georg Simmel's theory](_URL_0_) of what drives fashion)"
]
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1opnbm | how do mountain climbers keep themselves clean on large expeditions (ie: mount everest) | Question popped into my mind, and I got curious :) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1opnbm/eli5_how_do_mountain_climbers_keep_themselves/ | {
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"They don't really. Some bring baby wipes or something",
"Climbing say Everest, is a mammoth task. If you ever find yourself at base camp, you'll be more concerned with altitude and the effect it is having, possible life threatening situations, pulmonary embolism for example is common. Personal hygeine is just not a priority.",
"I've never climbed Everest, but I have done decently long backcountry trips in Alaska and the Yukon (up to 25 days straight), and the reality of it is that we just didn't worry about it. You just stink and deal with it. I took a couple occasional dips in lakes/rivers, but no soap or shampoo or anything. The only regular hygiene we observed was brushing teeth. Sure, everyone stinks, but you're busy enough with everything that you don't really worry about it too much, and after a few days you just sort of get used to it.\n\nReally interestingly though, after we got back to civilization, we stopped by a more structured camp site with showers. The shower felt great, and when I got out and picked up the clothes that I had previously been happily wearing for a couple weeks, the smell of them made me retch. Stuffed them in a garbage bag and tied it shut until I got a chance to wash them.\n\nI miss those backpacking trips. They were amazing.\n\n\n\n",
"Baby wipes, poop tube, and different priorities, makes sense thanks for the answers guys :)"
]
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1c8jna | what determines how words or names translated into english are spelled the way they are? | Like how is "Japan" derived from "Nippon". Why is the name "Jarminder" spelled that way in english, etc. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1c8jna/eli5_what_determines_how_words_or_names/ | {
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"There are two different things going on here. There is a process called transliteration, which is how you take words with a different character set and \"translate\" the sounds across into your character set. For example, it's how Москва (in cyrillic alphabet) becomes Moscow (in latin). Secondly, there's how place or person names become known in foreign languages. That's way less formal, and is often just \"whatever we first called these guys when we got here\". That's why Chinese people call their nation Zhōngguó, but we call it China."
]
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7d17kp | why is it that the area of a sphere (4 pi r^2) and the area of a circle (pi r^2) differ by a factor of 4? | It seems really weird that it's such a normal number. Is there an intuitive explanation as to why this is the case? Is there an easy way to map four circles onto the surface area of a sphere of the same radius?
In before someone helpfully informs me that the proper terminology is the "area of a disc," and the "surface area of a sphere," and that I misused the term "differ" and should instead prefer using "ratio." And that 4 isn't actually a "normal" number, because a "normal" number is something different. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7d17kp/eli5_why_is_it_that_the_area_of_a_sphere_4_pi_r2/ | {
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"That the surface area of a sphere is four times the area of a circle of the same radius is \"coincidental\". 4pir^2 is the first derivative of the formula for the *volume* of a sphere: 4pir^3 / 3. This sorta makes sense if you think of an infinitely small rise in r as being a infinitely-thin shell around the sphere, which is what the surface area is.",
"When we get into 3d space, we need to consider tiny tiny increments of change of radii. If we start from the middle and we move in any direction, the radius shrinks a tiny bit. Imagine you take one million of these little steps until the end of the sphere, where the radius is extremely small; say it was a million steps.\n\nIf we take an angle from the center of the midpoint to the side of one edge, it gives us an angle. That angle helps us find the cosine (a unit of comparison) length from the middle of the center circumference to the midpoint of the chosen edge. We now have a million little steps with a million Rcosine sides, where R is our radius. \n\nKnowing that 2piR is the circumference, we can say that the area of a sphere is estimated to be the result of [2piR x Sum(million Rcosine sides)]. This will give us from the midpoint to one of the tips, but our sphere has 2 tips, so we multiply it by 2. \n\n2[2piR x RSum millon Rcosine sides]. Factor the constants. Because R is just a number, we can pull it out as well... 4piR^2 x sum of a million cosine sides. From calculus, we can estimate that *Sum of a million cosine sides from the circumference of the center to the circumference of the top is 1 (this is an explanation all on its own). We end up with 4piR^2 = area of a circle. \n\nThis was a lot of information. All you need to know is that we measured a whole bunch of circumferences from the middle to the top, and found that their radius is decreasing, as we expect of a sphere. We then say, \"if we have enough of these circumferences, we basically have a million sided half-sphere, which is basically a sphere if we multiple it by 2\". The numbers just end up being nice, because we're only dealing with 2 Radii values, but adding (summing) them up to make a whole 3-d object. Sometimes it does not end up this nice. Also this is ELI5, so there is much more confident proofs out there when you enter real calculus reasoning, and not some liberties i took.\n\nHope it helped!\n\n",
"You're right, it's weird, and there's no intuitive explanation. \n\n/u/ItsSMC makes a heroic effort at an ELI5 version of the calculus proof of this. There's an older proof, before calculus, given by Archimedes in his book \"On the Sphere and Cylinder\". It's a tour de force of Greek geometry, and quite frankly the calculus method is easier to understand for modern readers.\n\nThis sort of surprise is why people get interested in mathematics."
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5pj7wk | why did people in the late 1700's dress so exotically? | Watching the movie Amadeus, I realized everyones attire was so over-the-top compared to what people wear today. Why was this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5pj7wk/eli5why_did_people_in_the_late_1700s_dress_so/ | {
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"The events you see in Amadeus are roughly equivalent to what you would see at an exclusive Hollywood club today. They are not representative of what most people wore at the time.\n\nWhat more, most people in that movie represent the idle rich, who have nothing better to than spend a month planning what they would wear to the big ball, then having their servants put it together.",
"Fashion goes in cycles. Someone from 1951 would see hippie clothes from 1971 as over the top. Look at what we think today of 1980s fashion. \n\nHistorically, only the rich could afford high-quality fabrics and showed their wealth through the clothes they wore. You will notice that the architecture of the time (Baroque) was also deliberately ornate, curvy and \"exotic\" compared to previous, more austere design and colour preferences - and those preferences were partly dictated by what was technologically possible and affordable (going further back, the invention of the flying buttress and with it the whole gothic cathedral made large, colourful windows possible, whereas previously, tall walls had to be thick to support their own weight and didn't allow large windows. Clothes and anything else that humans like to be pretty would be under similar \"technological\" constraints.)\n\nBill Bryson covers historical changes in fashion in his awesome book [At Home - A Short History of Private Life](_URL_0_) and notes that only in the 19th century did something like a \"butler's uniform\" become common because by that time, the Industrial Revolution had made good fabrics available to everyone and the rich needed some other way to distinguish servants from themselves. At the same time, the now powerful bourgeoisie chose a more sombre style - all those dark suits - to distinguish themselves (hard-working) from the aristocracy (lazy and outdated) and its over-the-top style."
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4t971j | the effects of a growing child in space, from conception to puberty | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4t971j/eli5_the_effects_of_a_growing_child_in_space_from/ | {
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"No one knows.\n\n\nWe can make some guesses, but fact is that we haven't mapped yet how much our bodies rely on gravity to form structures, to orient themselves when differentiating cells.\n\n\nWould a zygote even attach in the womb without gravity?",
"I'd imagine that bone structure would be weaker than normal - due to ZG, which could be an issue at delivery, babies skulls are soft and malleable as it is! This could possibly require all babies born in space to be C-sectioned or 'sun roof babies'. This in turn could present significant issues associated with performing surgery in space!\n\nHowever as far as gestation goes, because nutrients and waste is delivered/removed by the umbilical cord I would expect it to be mostly issue free...\n\nAs would the majority of its growth the rest of its life, providing it received the required nutrients, education and other nurturing as stated previously the only real issue would be returning to gravity after spending it's entire life in ZG would be a completely unknown scenario.\n\n\nEdit: added a little bit about post birth to puberty.\n",
"From what I heard conception would already be difficult because your body has a hard time keeping it hard in zero G.",
"We don't know the answer to this question, so everything you hear here will be at best an educated guess. \n\nWe are still trying to determine how microgravity and the space station environment affect fully grown adults, much less developing children. And I can't see us starting experiments to find out anytime soon tbh. Maybe if we start talking about longer manned flights such that the possibility of children developing aboard a spaceship becomes very real",
"Vsauce has a video talking about it actually. It's been a long time since I've watched it, but give it a watch and see what you think. _URL_0_"
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j357e | [li5] can someone explain human migration to me | Specifically, having a look at [this.](_URL_0_) The Goths came from modern day Scandinavia, but when the hell did people migrate that far north in the first place? who were they? I had thought the flow of civilisation was northward, but appears not to be the case.
What was the first migration north, out of Africa? Was there one major migration north where people just thought 'this is a sunny spot, I'm not going any further' while the rest kept going? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/j357e/li5_can_someone_explain_human_migration_to_me/ | {
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"Someone will eventually give a better answer than this, but for now...\n\nAs i understand it the main driving force is that populations grow. \n\nTribe A lives in Valley X.\n\nTribe A after a couple generations is a lot bigger. Too many for Valley X to support.\n\nTribe B splits off from Tribe A and moves into Valley Y.\n\nTribe B grows big, Original Tribe A never stopped either. \nTribe A splits again and Tribe C is formed... Meanwhile Tribe B has Tribe D split off of it. Both Valley X and Y are still over populated. So Tribe D moves on to Valley Z. \nTribe C coming from A think they are king shit and say to Tribe B, screw you Valley Y is now ours... \nTribe B loses a battle to Tribe C and are pushed out of Valley Y. They are too weak to take on Tribe D for Valley Z so they move on to Grassland X instead.\n\nThink of that repeated over and over and over again, sometimes instead of a Tribe it's a whole nation worth of people pushed out....\n\nI remember reading somewhere that the whole Vandal sacking of Rome was actually a result of the Mongols chasing the Vandals out of the original Vandal-land. (very loose recollection there and obviously it wasn't called Vandal-land, or not even the Vandals at all, Visigoths maybe? something else? i forget.)\n\nObviously my response doesnt answer your specific question re the Goths and Scandinavia... but, oh well. My fingers need the exercise.\n\nEdit: i also suspect much of the original settlement of places like Scandinavia happened in the thousands of years before we could realistically have any idea of who settled what and when, and THEY prolly pushed out the Neanderthals before that...\n"
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21fu1l | what does the northwestern athletes obtaining the right to unionize do? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/21fu1l/eli5_what_does_the_northwestern_athletes/ | {
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"The same thing all unionizing efforts seek: increased bargaining power. \n\nExample: \n\nNon-union - QB wants less practice time during the weekends so he can study more. Coach disagrees, he is removed from the team and backup QB takes his place. \n\nUnion - QB wants less practice time during the weekends so he can study more. QB tells his union rep who see's if this is something all the players want. If yes, union asks for less weekend practice. If the coach disagrees, he's now not only dealing with the QB, but the entire team/union. It is much harder to simply 'remove' the entire football team than one player who seeks change. \n\nedit: spelling"
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1jp89i | what is the purpose of graffiti "tags"? is there some sort of cred system? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jp89i/what_is_the_purpose_of_graffiti_tags_is_there/ | {
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"[Watch this movie.](_URL_0_)",
"From what I know, tagging is like one group's way of claiming a territory or a spot. And when a rival group crosses it out, and tags their own graffitti then its a sign of disrespect . "
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6i0qih | how come whenever slow-motion replays are shown in sports, the scoreboard appears to be flickering? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6i0qih/eli5_how_come_whenever_slowmotion_replays_are/ | {
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"When you are looking at a screen (computer, phone, tv etc..) you aren't looking at something real like when you are looking at a football player. The screen is redrawing itself over and over so fast that you see it as a thing, just like you see anything in the world.\n\nWhen you film something, it is also filming like that. It is taking many pictures per second, not a constant capture of what is in front of the lens. \n\nIf you film a screen at the same rate that the screen refreshes and display it at that rate the screen looks like a thing. If you modify the film, like slow it down, now you are seeing how the screen refresh, or flicker. \n",
"Most scoreboards are made up of LEDs. Unlike normal lightbulbs, LEDs require a driver circuit to deliver the proper voltage to them. In order to save money, many LEDs will share the same driver circuit. The system quickly switches which LED the driver is powering. So at any given time, large sections of the LEDs are off. Which section is off rapidly changes. To the human eye, that happens far too quickly for us to notice, however the slow motion cameras capture video at a very high frame rate. Because of this the camera will always show some of the LEDs turned off. The flickering comes from the pattern of \"off\" LEDs shifting across the scoreboard. "
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1revkv | why does ancient structures like the old roman roads are still in pretty good shape hundreds if not thousand of years after their construction, yet modern structures are already breaking up only decades after they were made? | For example, a bridge in Montreal is barely standing yet is only 51 years old, but the Coliseum is many times that and still standing (ok except that big part we never restored).
I know use is part of the answer, but surely there's more to that? Modern structures should be better made than old ones after all!
EDIT: Thanks to all of you for the answers! Now if a mod could tag this solved that'd be great, because I'm on mobile so I can only tag NSFW | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1revkv/eli5_why_does_ancient_structures_like_the_old/ | {
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"Roman Concrete didn't have iron or steel bars running through it. The iron or steel bars add strength to the concrete, but if it's not constantly cared for properly water will get into the cracks and cause the iron to rust which will cause the bars to expand and break the concrete. ",
"There are loads and loads of Roman Buildings that only lasted 50 years, or so. They're just not around any more.\n\nThis is a kind of confirmation bias. *Of course* all Roman buildings we see lasted hundreds of years. That's why we can still see them.\n\nI imagine there are some modern buildings that could last a similar length of time, but I can't think of any right now. :-/",
"Comparing the best constructed ancient structures to the most poorly constructed modern ones isn't really a fair comparison... most old structures didn't get the craftsmanship that the Coliseum and the like did (and thus aren't around).\n\nA lot of places like cold-weather Montreal have more challenging environmental conditions than ancient Rome. Water seeps in, freezes, expands - that will destroy structures faster than a year-round Mediterranean climate.\n\nUltimately though, it's cost. Modern building techniques are way faster than laying down stone by hand. Construction is measured in months instead of decades. It's a cost / benefit trade off. The goal of those types of modern buildings isn't to make them last a millennium with zero upkeep. ",
"In olden days builders did not have access to materials science or computer testing. If they wanted a bridge to stay up it had to be overengineered. Today they can build far lighter and economical bridges and structures, the downside being that they have a more limited design life.\n\nAlso you dont hear about the roman bridges that fell down after 50 years ",
"A couple of reasons:\n\n1. As stated above, confirmation bias. Of many millions of ancient buildings all across the world, only the strongest still survive. In a thousand years, the same will probably be true of our structures.\n\n2. Speaking specifically of your comparison, weather conditions in Italy are more favorable for preserving a large concrete structure.\n\n3. Many ancient structures have been rigorously maintained. For example, the Colosseum has a [very large brick support structure that was built in the 1800s for the specific purpose](_URL_0_). Other Roman-era buildings, such as [this church in Trier](_URL_1_) or [the Hagia Sophia in Instanbul](_URL_2_), remain in excellent condition because they have been in constant use since their construction (though not necessarily for their intended purpose)."
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3thklq | why do we put flowers on a grave? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3thklq/eli5_why_do_we_put_flowers_on_a_grave/ | {
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"The tradition is so old that no one knows how it started.\n\nTheories include (1) flowers are simply nice; (2) cut flowers symbolize mortality because they are beautiful yet, having been cut, are already dying; (3) some idea that spirits may like flowers"
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auo3xa | does our food dna affect our dna? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/auo3xa/eli5_does_our_food_dna_affect_our_dna/ | {
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"It doesn't, not directly at least. The DNA of the food we eat has no direct effect on the DNA in our cells. It sounds like you have some idea about how these two things should interact. Would you care to share that with us?",
"The food that you eat is derived from plants and animals for the most part. These may have DNA in them, along with many other things. However, when you eat them, you digest them in your mouth, stomach, and intestinal system, which causes the DNA and many other components to be broken down into the basic building blocks that they are made out of. For the most part, food DNA does not affect our DNA because it is too broken down to do anything besides be used by our body as building blocks. Some food we eat may not be broken down and cause an effect. This is often seen with toxins from bacteria that we might eat and get food poisoning from. So there is definitely no definite answer, but for the most part, almost all of the food we eat is broken down into building blocks before it enters our body, especially the DNA that we ingest.",
"Not really. When food goes through your digestive system, it gets broken down into its components so the resulting pieces can be used by cells. In this case, the resulting molecules would be used to create DNA that matches the code of dividing cells within the body. \n While the DNA is going through the digestive tract, it isn't being used as instructions to create proteins, so it's not changing anything within the eater's body. \n"
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654x0b | if the cells in our body get replaced regularly, why does our hearing and eyesight not get repaired? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/654x0b/eli5_if_the_cells_in_our_body_get_replaced/ | {
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"I'm not an expert but I believe that we have poor eyesight due to our cornea being misshaped and not focusing the light onto our retina correctly. When the cells get replaced the do not affect the overall shape of the cornea hence not repairing your eyesight. \n\nI am not an expert (although I do wear glasses), so feel free to correct me if I'm wrong.",
"Not every cell gets replaced. Some types of cell cannot be. That's why brain damage is permanent and why hearing loss and vision loss occur. These cells don't replicate and once they're gone they're gone. \n\nEdit: spelling",
"I wish they'd figure it out, my tinnitus has been a hindrance for years and I'm only hitting 22.",
"Neurons (nerve cells) are not generally replaced. Some parts of the brain like the hippocampus (involved in learning, memory, spatial ability) gets new neurons, but peripheral sensory nerves (photoreceptors in the eyes and neurons in the optic nerve) are never replaced if damaged.",
"Even when cells do replicate themselves there are tiny parts at the end of each replication that get left behind those leading to a loss of information. ",
"As for our vision, poor eyesight can be due to the cornea being misshaped, lens being misshaped, or because the length of the eye is either too short (causing you to be farsighted, or hyperopic) or too long (causing you to be nearsighted, or myopic). It could also be due to a combination of these three, among other things!\n\nAll of these primarily cause rays coming from the outside to not hit the back of your eye very precisely, which is where you have cells called photoreceptors (rods and cones). This is why we wear glasses and contacts, which alter these rays so they hit these cells accurately and precisely. These cells can, and are, regenerated and replaced regularly. \n\nHowever, the neurons that send the signals from these photoreceptors to the brain are not replaced, which is why ocular diseases such as glaucoma, which damage the neurons, cannot be cured. \n\nOther ocular diseases can impact any part of the entire visual process, however, those that affect the neurons usually end up in blindness if not properly treated (or slowed).",
"Understanding the cell cycle can help to explain this. The cell cycle consists of mitosis and interphase. Interphase is further divided into growth phase 1 (G1), DNA synthesis/replication (S), and growth phase 2 (G2). The transitioning between the different phases is regulated by different proteins called cyclin dependent kinases (CDK) and tumor suppressor genes like p53 and RB. Furthermore there is an additional phase called G0, this is the phase that permanent cells reside in, this includes neurons, skeletal and cardiac muscles, and red blood cells. Permanent cells do not replicate, they don't go into mitosis, and they must be regenerated by differentiation of stem cells. The next type of cell is stable or \"quiescent,\" this type of cell normally resides in G0 but under certain circumstances they can be stimulated to enter G1 and then to further progress through the cell cycle and into mitosis in order to replicate. Examples of stable cells would be the cells that make up your liver and white blood cells. The third cell type is know as labile, these cells never enter G0, they divide rapidly and have a short G1 phase and continue through the cell cycle. Examples of labile cells include bone marrow, the cells lining your gut, hair follicles, and germ cells. \n\nThe reason that we have regulations and checkpoints is to prevent cells from growing uncontrollably. For example if a cell notices that it's DNA is damaged it will trigger apoptosis or programmed cell death. This is what happens when we get a sunburn. UV rays damage the DNA and so to prevent from mutations in the genome (skin cancer) from spreading, the cells sacrifice themselves (pealing sunburned skin). Another point worth mentioning is that labile cells are most at risk for becoming cancerous. Mutations in these cells can lead to colon cancer, cervical cancer, or skin cancer. Mutations in the regulatory genes can also cause cancer's. For example p53 is mutated in most human cancers, p53 blocks G1 to S phase, another example is Rb mutation causing retinoblastoma it also is involved in regulating G1 to S phase.",
"[This comment](_URL_0_) does a really good job of explaining it, but it's suuuuper long, so I'll let you go there to read it. Here's the gist, though:\n > Now here is the interesting one: Nerval tissue. Do nerves regenerate? Yeah, kind of! ... but not everywhere. See, there are two compartments to the nervous system: the central nervous system (all parts of the nervous system that are embedded in bone cavities, i.e. the skull and the vertebral column) and the periphery nervous system (all nerves that exit the central nervous system, i.e. all the nerves in the limbs, the torso and the head outside of the skull). Most nerves are embedded in a substance called myelin - basically like cable insulation, increases the conduction speed. That is not all they can do though: the cells that build the myelin - called glia cells - also nurture and maintain the actual nerve fibers. The periphery and the central nervous system has different kinds of glia cells. Central has a variation like oligodendrocytes and others, periphery has schwann cells. schwann cells are capable of repairing lesions in nerval tissue and grow periphery nerves back together, given that they are still in the same place of course. Central nerves and their glia cells... well, simply put they just dont. Have a damage in your spinal cord or your brain? Tough luck, those glia cells just cant. Additionally there are usually no real inflammatory processes in the brain that could kickstart a healing process (and inflammation in the brain is... well, pretty much lethal, so nature kind of had to do it like that). There ARE small stem cell populations in the brain that supposedly can regenerate damaged nerves, but they dont seem to do a significant enough job because spinal cord damage and strokes are pretty much permanent. - u/GrafKarpador\n\nAlso, to those saying it's impossible, [you absolutely can and do regenerate neurons!](_URL_2_)\n\nEdit: [Here's](_URL_1_) another fun little explanation on how neuron regeneration works, specifically in regards to reacquiring the ability to see, breathe, etc. We're not quite there yet, but it's definitely within the realm of possibility thanks to stem cell research!\n\nEdit: Even without stem cells, you can regenerate neurons, but as a lot of commenters have pointed out, the healing if often clunky and inefficient, so while it is possible, our neurons just can't reproduce quite enough to cure any conditions like OP mentioned.",
"Hearing and eyesight are part of the central nervous system (CNS). The CNS has glial cells, these are bodies that surround neurons. One of these glial cells are astrocytes. When the CNS gets damaged, the astrocytes occupy the damaged area to prevent regeneration.",
"Your cells are making an increasingly bad copies of themselves. Aging is a photocopy of a photocopy of a photocopy.",
"Because they get replaced bad. \n\nIf you have a big scar for exemple, all cells that form the scar get replaced regularly, but at the same place. The scar get repaired, maintained.\n\nSame with eyesight and hearing.",
"Neurons aren't replaced for survival advantages. Things like memories and primal instincts wouldn't exist if those cells were constantly replaced. Our species has better long term survival with a limited lifespan of 70-90 years, than with regenerating neurons which would allow us, individually, to live much longer.",
"To put it simply. Think of a garden sprinkler, the ones that spray in an arch. The cells are the water, and the sprinkler is the cell bed. Well after a while, you could damage the sprinkler, causing the water to spray differently, but it's still working fine. And if it gets damaged enough, even though it's still spraying water like before, it's not nearly as efficient, and starts causing pattern issues. Some spots more water, some spots have random jets all over this place, one nozzle seems clogged. And the damage could be done by external forces, age, or even manufacturing defects (Damn genetics). \n\nBut the main difference is, when your cells aren't being formed correctly, it causes mutations. Now, mutations are a little more tricky to explain so this next bit will be middle school science. \n\nDepending on the different type of cell you can get different kinds of mutations. With skin, you could get scars, sensitivity, or you could even have overproduction of skin like psoriasis. With eyes, you can get anything from a spec in your vision, to hazy vision, to down right blindness. All because the cells don't come out just right. \n\nThe human body really is amazing. "
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"https://www.ted.com/talks/sandrine_thuret_you_can_grow_new_brain_cells_here_s_how/transcript?language=en"
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55gihu | what limits creature size here on earth? | Why is it that we seem to have stopped at the blue whale? Is it possible that larger creatures could exist? How much larger? Would they have to be sea creatures?
Also, If we stretched the rules a little bit, what is the largest a creature could be here on earth? (Land or sea). | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/55gihu/eli5_what_limits_creature_size_here_on_earth/ | {
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"Hypothetically, there is nothing stopping anything larger than the blue whale from existing. \nAny larger creature would probably have to be a sea creature, the buoyancy of the water would help to support the enormous skeletal structures that probably wouldn't be possible on land. \nI believe however one of the greatest limiting factors would be availability of food. Blue whales are estimated to eat 3-4 tonnes of food everyday, a larger creature is going to need more than that, multiply that by multiple organisms in order for the population to breed and you start to get a huge amount of food that earth may just not be able to provide. \n\n",
"Oxygen and the square root law. \n\nNot enough oxygen to support large organisms like the dinosaurs and then you have increase energy exponentially the larger a creature become in order to hold up its own weight. ",
"Well salt water crocodiles experience indeterminate growth. Meaning that they continue growing until they die. However, stress during formative years, food consumption, and competition all impact the growth of a croc. Most animals have a determinate size most likely realized through evolutionary needs and adaption. For example creatures of prey probably evolved to be smaller in order to be more nimble so they don't get caught as easily by predators. That's just my guess though... there's probably a more in depth explanation out there.",
"Gravity and oxygen; without oxygen you don't have the energy to be big, while gravity puts a huge limit on mobility. Essentially, when you become very massive, you need to add more limbs to distribute weight, or lose limbs and root yourself.",
"Oxygen saturation and transfer efficiency makes it hard to have a large creature that can move quickly. Thermal transfer and dumping said heat puts a limit on size for creatures. Gravity and the load limit on things like bones sets an upper end on how big a thing can be without crushing. Nutrition requirements mean things eat more as they get bigger but it gets harder to find the food when you are huge. Blue whales exist at an outer edge of the envelope given present conditions and what biology is able to come up with by chance, relying on water to hold the weight and pull away heat, floating to limit how much energy they put out, and eating craptons of little plankton that can be sucked through in a constant buffet.",
"I remember hearing somewhere that if the oxygen content of our air was 50% higher then we'd have spiders the size of dogs, because arachnids and insects breathe through their skin/exoskeleton as opposed to with lungs. So yeah. Fuck that. Nature's scary enough.",
"Here are a few basic concepts that could explain\n-Oxygen(square root law)\n-Lack of resources(law of 10% or something)\nBasically, the larger an organism is, the more inherently inefficient it is. Also, as an organism becomes longer and larger, it soon becomes impossible to effectively pump blood throughout the body; as a result of this, it is difficult for larger animals to move, and therefore actually find/catch/consume food to support their massive bodies and keep up with the massive heat loss they are experiencing due to their gigantic surface area. You probably heard in like elementary school that \"back when there were dinosaurs, insects were huge because there was so much oxygen\", this is represented by that square root law because it was only by the saturation of oxygen in the atmosphere that allowed them to actually move and grow to such sizes. You've probably also heard of dinosaurs such as the supersaurus, that physically could not lift their heads or basically move them around too much without breaking them and therefore dying, or being able to pump oxygen effectively to the brain, passing out, and dying. So basically, if the earth were smaller and the oxygen density of our atmosphere was something much higher than 21%, then you would see some much larger organisms, if life could even exist.\n\n",
"Mostly gravity, due to bone density. Which is why whales can get really big since theyre suspended in water. But eventually an animal reaches a point where it's organs are so large that the animal cannot support its own weight, because while bones are extremely strong the larger an animal gets the larger it's bones need to be, and the larger it's bones need to be the bigger it's organs need to be to support it. Oxygen supply in the atmosphere also plays a part, which is why dinosaurs (and mammals, bugs, etc even) could get so big at more oxygen rich parts of earths .history"
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5vg9wd | how can the smallest parts of the bits that make up atoms be made up of... nothing? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5vg9wd/eli5_how_can_the_smallest_parts_of_the_bits_that/ | {
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"they aren't made up of nothing. there just isn't any smaller parts you can break them up into. \n\nso atoms are made of electrons, protons, and neutrons, right?\n\nelectrons are elementary particles. you can't break an electron into anything smaller.\n\nbut neutrons and protons - they're made of three quarks. quarks are elementary particles and have a weird quirk (get it?) where the energy required to separate individual quarks is large enough that it ends up creates more quarks. you can't separate them, really.\n\nthere's other elementary particles too - like neutrinos and positrons and other weird things that have more to do with radiation and balancing energy equations then they have to do with atoms.\n\nyou didn't learn it in school because quantum physics would severely complicate the explanation of chemistry you learned in school. it's like how they didn't explain why atoms were made up of smaller bits when you were in elementary school"
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26f3sk | how come i can put on someone's prescription glasses and, while it's blurry at first, i can focus, but they can't just focus their eyes without glasses? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/26f3sk/eli5how_come_i_can_put_on_someones_prescription/ | {
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"text": [
"Perhaps you have more flexible focus. I guarantee you, though, if you put on my glasses you wouldn't be able to see a thing. It sounds like you experimented with glasses that have a fairly weak prescription.",
"You can to some extent depending on how bad your vision is, but it's extremely tiring and often leads to headaches. \n\nYou also get used to wearing glasses. I went for years without glasses, but when I remove them now I see worse than before I got them. I'd probably adjust and see a bit better if I stopped using them for a while, but it would be very taxing on my eye muscles."
]
} | []
| []
| [
[],
[]
]
|
||
2ttugm | if it's so difficult to cool things down in space, how do satellites and the iss not overheat from sunlight? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ttugm/eli5_if_its_so_difficult_to_cool_things_down_in/ | {
"a_id": [
"co29cfr",
"co29dif",
"co2en35"
],
"score": [
25,
2,
16
],
"text": [
"Most surfaces are painted white or coated in reflective material to reduce absorption of sunlight.\nThere may also be areas painted black that face away from the sun that radiate heat.\n\nWhite absorbs light/IR the least, but also radiates heat the least.\nBlack absorbs the most, but radiates the most too. By using both in the right positions, the temperature can be controlled.\n\nThermal management is basically all about moving heat to a part of the spacecraft designed to radiate heat to keep the craft cool.",
"If you cover a satellite with reflective material (think aluminum foil) it will reflect light rather than absorb it. To keep cool, all you have to do is radiate more heat than you absorb.\n\n\nIn addition, satellites in a low orbit will be out of the sun for half of the orbit.\n",
"Everything radiates heat away. It's just a matter of allowing enough heat to radiate away to keep it cool. There are several ways to do this:\n\n\n1. For certain orbits, the satellite will spend nearly half its time in the Earth's shadow, giving it more time to cool off.\n\n\n2. Rotating the spacecraft keeps it cooler than having it stationary. Basically, hotter things radiate heat faster. So if you just have one all-light side and one all-dark side, the dark side doesn't radiate heat very quickly. But if you continuously rotate, the dark side will still be warm from the sunlight, so it will radiate heat more quickly. The Apollo missions used this method.\n\n\n3. Some larger spacecraft (e.g. ISS) have radiators. These are large, flat fins that usually have a fluid (e.g. NH3) running through them. This fluid carries heat away from the spacecraft and into the radiators, where it radiates out into space. The trick with radiators is the orientation: if you angle them so that the flat edge is pointing towards the sun, then the radiators themselves are absorbing practically zero sunlight (since they have a very small cross-section in that direction). But since they have a lot of surface area pointing in other directions, they can radiate massive amount of heat away into space.\n\n\nI hope that helps."
]
} | []
| []
| [
[],
[],
[]
]
|
||
c5zz4f | how are mobile check deposits accepted by banks if they never even get to see them up close? | I always deposit my checks and the money is usually available the next day, sometimes even the same day. But, what protects these companies from fraud? How do they know the check isn’t a fake? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c5zz4f/eli5_how_are_mobile_check_deposits_accepted_by/ | {
"a_id": [
"es58lpk"
],
"score": [
2
],
"text": [
"Essentially they use an ACH system to “cash” the check before you are given the money. \n\nIf the check were fraudulent they would know before it is fully deposited into your account."
]
} | []
| []
| [
[]
]
|
|
6dnbpv | why is it an "exclamation point" and a "question mark?" | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6dnbpv/eli5_why_is_it_an_exclamation_point_and_a/ | {
"a_id": [
"di3y66s"
],
"score": [
11
],
"text": [
"It *is* [exclamation mark](_URL_0_). Depending on where you live.\n\nAnd the question mark is also known as an [interrogation point](_URL_1_) although that is a less common thing to call it."
]
} | []
| []
| [
[
"https://en.wikipedia.org/wiki/Exclamation_mark",
"https://en.wikipedia.org/wiki/Question_mark"
]
]
|
||
4f7qeu | anti-gravity flights? | Do they just fall in a way that balances out the force caused by gravity? And if so, how do they maintain that so safely? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4f7qeu/eli5_antigravity_flights/ | {
"a_id": [
"d26jwjw",
"d26k5or",
"d26kifv",
"d26klna",
"d26ktez"
],
"score": [
2,
3,
3,
3,
5
],
"text": [
"The plane flies to about 34,000 feet and then puts the nose down to a 30^o angle. This simulates zero gravity because you're falling as fast as gravity is pulling you. The plane pulls up at about 24,000 feet and climbs back to the starting altitude where they do it all over again. \n\n[Graphic](_URL_0_)",
"Imaging throwing a throwing a ball high into the air. It will travel in an arc, a curve known as a parabola.\n\nNow image that ball was surrounded by an airplane, travelling at just the right speed and direction, so the ball appeared motionless with respect to the inside of the plane. \n\nThat is pretty much what a zero-G flight is doing.",
"If you were in an elevator and somebody cut the cable, the elevator would fall and so would you. You would seem to float because the floor is falling at the same rate you are. The plane does basically the same thing. ",
"You seem to understand correctly. They are not actually anti-gravity. They are simulating a no-gravity situation by putting the plane into a *free fall* trajectory, that is, making the plane plummet at exactly the same speed that a falling weight (or a falling body) would do if there were no wind resistance. Since you're surrounded by a plane that's falling the same as you are, you feel like you are floating. In reality you're both plummeting.\n\nSide note: this is exactly what happens in space capsules in orbit. The only differences are (1) they are outside most of the atmosphere and (2) a rocket has given them so much sideways velocity that they never actually hit the ground -- they keep falling and keep missing.",
"Here's a [pretty good explanation](_URL_0_) from a couple of guys who actually worked under these conditions to make a music video."
]
} | []
| []
| [
[
"http://s.hswstatic.com/gif/zero-g-4.jpg"
],
[],
[],
[],
[
"https://www.youtube.com/watch?v=bMrX014HTgU"
]
]
|
|
5ddd2v | why do we wave our hands when we say goodbye? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ddd2v/eli5_why_do_we_wave_our_hands_when_we_say_goodbye/ | {
"a_id": [
"da3osu0",
"da3sqb8"
],
"score": [
3,
8
],
"text": [
"As I understand it people used to wave 'backwards' moving their had towards themselves indicating they wanted the person to come back. From there it just sort of devolved.",
"Explanation through argumentation:\n\nDescribe to me a better way to communicate a message from a distance with as low a chance of misinterpretation. \n\nThe evolution of a wave as the best way to catch attention from a distance to a method of communicating awareness of the existence of the other (to greet or to farewell) follows.\n\nIf you had no technology, and you wanted to show somebody that you were thinking of them, what bodily motion would you use?"
]
} | []
| []
| [
[],
[]
]
|
||
3lvp0z | why can't climbers parachute down mt. everest after climbing it? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3lvp0z/eli5_why_cant_climbers_parachute_down_mt_everest/ | {
"a_id": [
"cv9p2it",
"cv9p2ww"
],
"score": [
3,
3
],
"text": [
"I imagine turbulent winds make it impossible. Imagine being blown into sharp icy cliffs. That's a wrap on the rest of the trip right there.",
"Someone hang-glided down a year or so ago. \n\nIt was an extremely dangerous proposition even for the very experienced climber and hang-glider, though. Up that high the air is thinned, you don't get the lift you might expect, and sudden gusts can get you killed regardless of experienced. Even if you make a landing, it you get too far off course the idea of hiking back down from more remote, less stable places can still kill you; just being blown off course can be bad. There are bodies in *eyesight* of the official paths that nobody is willing to risk going over to, remember.\n\nIt's safer to go back down on foot."
]
} | []
| []
| [
[],
[]
]
|
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