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1lr9w8
|
why have no video game consoles made a move towards allowing keyboard and mouse inputs?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1lr9w8/why_have_no_video_game_consoles_made_a_move/
|
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"Keyboard + mouse don't work so well when you're sitting on the couch.\n\nThe PS3 supports KB + mouse but I don't know how many games use them.",
"That's called a computer. But seriously, I suspect it's to perpetuate a divide between computers and consoles so console buyers don't think they're just buying lame computers.",
"At least with the PS3, it's not the console's fault at all. IIRC they, freely allow the developer to implement in their game if they want. Only a tiny handful of developers have elected to do that, however. \n\nI think the biggest reason is balancing the multiplayer experience. However, there is talk of BF4 having M/K support. All I know is that whenever the two get combined (controllers and kb+m) the controller users tend to get a little rage quit-y. The [top skill ceiling possible](_URL_0_) with a mouse is far beyond that of a controller, like at a ridiculous level, so over time you might see one population win out. ",
"Because in terms of usability and function m/k will always(tm) work better than a controller. With te most obvious reason to me being that a joystick is made to not move when the controller is tilted, making it harder for controller users to have as quick reaction.",
"Honestly, some people prefer controllers to mice and keyboards. I personally prefer a controller for a casual FPS or RPG especially since I don't get a stiff neck or lag from consoles, but when I'm playing a MOBA or RTS game, I love the variation of a keyboard.",
"The SNES had a mouse attachment for Mario Paint.",
"Dust 514 for the PS3 has full mouse and keyboard support. Makes it far to easy though. I've even heard of people getting kicked from a match for \"hacking\" since they have such a high kill/death ratio compared to everyone else using controller."
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.youtube.com/watch?feature=player_detailpage&v=mHo4l-qmGHI#t=37"
],
[],
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[],
[]
] |
||
7v3dzd
|
why all living things (almost) try their best to produce offsprings?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7v3dzd/eli5_why_all_living_things_almost_try_their_best/
|
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"I notice a lot of these natural selection questions are a lot easier to understand if you question the fate of the opposite, in this case the answer becomes clearer if you ask instead \"What happened to the living things that didn't try their best to produce offspring?\" Well they had fewer heirs and eventually died out from competition.\n\nThis applies to other questions too. \"How did these hatchling lizards from Planet Earth II know to flee from snakes?\" Well the ones who didn't were eaten long ago already, the hatchlings are all born from parents who had the instinct to flee from snakes."
]
}
|
[] |
[] |
[
[]
] |
||
68yy09
|
how theoretically big would a species need to be in order to be intelligent?
|
So often when comparing species intelligence we look at brain size relative to their body weight. However there must a size of a species that is a minimum because only so many neural connections could be made. What is that theoretical size?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/68yy09/eli5_how_theoretically_big_would_a_species_need/
|
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"What does \"intelligent\" mean? As intelligent as humans? Not quite as capable, but close? Parrots and a few other kinds of birds are quite intelligent and relatively small. Octopuses are generally very intelligent, and some can be very small. Cuttlefish fall into this category as well.\n\nI won't pretend I have an answer for you, but I think you need to be more clear if you want one. Minimum size for *how* intelligent? Where are you drawing the line?\n\n",
"I studied brain science in university.\n\nThe truth is that no one knows. The theoretical models of how intelligence works are not well-enough developed. We do know that intelligence requires a certain level of complexity, but we don't know how much complexity can be represented in a given number of neurons.\n\nMore neurons are in general better, but for example a parrot has substantial intelligence in a brain *far* smaller than a human brain."
]
}
|
[] |
[] |
[
[],
[]
] |
|
kq3ng
|
computer architectures and the differences
between them
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/kq3ng/eli5_computer_architectures_and_the_differences/
|
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"Edit: corrected and finished my explanation.\n\nThe brain of a computer is called the CPU.\n\nEssentially all CPUs only speak a primitive language consisting of just \"yes\" and \"no\" - or 1 and 0. This way, they're efficient to make.\n\nThese 1's and 0's are used to tell the CPU what to compute.\n\nThe *instruction* (or *opcode*) `100101010` might tell one CPU to add two numbers, it might tell another CPU to *subtract* two numbers, and it might even be an invalid instruction for another CPU.\n\nThe set of all the instructions that a CPU understands is called the *instruction set*.\n\nA *CPU architecture* defines the logical model (using logic gates - see Wikipedia) of how the CPU implements its instruction set. Two different architectures may very well implement the same instruction set.\n\nAn instruction set defines *what* that CPU will understand. The architecture defines *how* it understands it.",
"Hey OP... my reply had factual errors, and didn't explain what an architecture actually was. I've corrected and finished it. I'm making another reply so you get the orangered.",
"There are two commonly used different meanings of the term \"architecture\" here.\n\nOne is \"Instruction Set Architecture\" (ISA) and one is \"micro-architecture.\"\n\n* The different instruction set architectures would be things like x86, MIPS, SPARC, VAX, IBM-360, 8051, 680x0, Itanium, PowerPC, etc.\n\n* The different micro-architectures would explain why different chips all implementing the same (or similar) x86 Instruction Set Architecture, perform differently. (Pentium-II, Pentium4, Core2, etc.)\n\nThis is further complicated by the fact that there are different versions of each ISA, as it is extended over time. E.g., the x86 eventually had MMX extensions, then grew to x86_64, added SSE, SSE2, etc., etc.\n\nThe differences between microarchitectures are as follows:\n\n* Changes in cache size, branch prediction algorithms, pipelining, width of instruction issue, etc. **These things generally are not visible to software.** They just make some chips run code \"better\" than others.\n\nThe differences between Instruction Set Architectures are as follows:\n\n* **These are very visible to software.** The software model of each ISA is different from others. They may have different numbers of user visible registers, they may be of different widths in different ISAs, some may be special purpose registers, others general purpose. The Special Purpose registers are *completely* different between ISAs. The \"Kernel Model\" that Operatings Systems see will be completely different between them (I.e., all the magic registers that set up things like what features are enabled/disabled, the memory management model, etc.)\n\n* For a simple example, some ISAs may have an integer multiply instruction, others might instead have a \"multiply step\" instruction that you would have to run several times to multiply, yet others might not have any multiply instruction at all, and you'd have to do a bunch of \"adds and shifts\" to get the same result.\n\n",
"Edit: corrected and finished my explanation.\n\nThe brain of a computer is called the CPU.\n\nEssentially all CPUs only speak a primitive language consisting of just \"yes\" and \"no\" - or 1 and 0. This way, they're efficient to make.\n\nThese 1's and 0's are used to tell the CPU what to compute.\n\nThe *instruction* (or *opcode*) `100101010` might tell one CPU to add two numbers, it might tell another CPU to *subtract* two numbers, and it might even be an invalid instruction for another CPU.\n\nThe set of all the instructions that a CPU understands is called the *instruction set*.\n\nA *CPU architecture* defines the logical model (using logic gates - see Wikipedia) of how the CPU implements its instruction set. Two different architectures may very well implement the same instruction set.\n\nAn instruction set defines *what* that CPU will understand. The architecture defines *how* it understands it.",
"Hey OP... my reply had factual errors, and didn't explain what an architecture actually was. I've corrected and finished it. I'm making another reply so you get the orangered.",
"There are two commonly used different meanings of the term \"architecture\" here.\n\nOne is \"Instruction Set Architecture\" (ISA) and one is \"micro-architecture.\"\n\n* The different instruction set architectures would be things like x86, MIPS, SPARC, VAX, IBM-360, 8051, 680x0, Itanium, PowerPC, etc.\n\n* The different micro-architectures would explain why different chips all implementing the same (or similar) x86 Instruction Set Architecture, perform differently. (Pentium-II, Pentium4, Core2, etc.)\n\nThis is further complicated by the fact that there are different versions of each ISA, as it is extended over time. E.g., the x86 eventually had MMX extensions, then grew to x86_64, added SSE, SSE2, etc., etc.\n\nThe differences between microarchitectures are as follows:\n\n* Changes in cache size, branch prediction algorithms, pipelining, width of instruction issue, etc. **These things generally are not visible to software.** They just make some chips run code \"better\" than others.\n\nThe differences between Instruction Set Architectures are as follows:\n\n* **These are very visible to software.** The software model of each ISA is different from others. They may have different numbers of user visible registers, they may be of different widths in different ISAs, some may be special purpose registers, others general purpose. The Special Purpose registers are *completely* different between ISAs. The \"Kernel Model\" that Operatings Systems see will be completely different between them (I.e., all the magic registers that set up things like what features are enabled/disabled, the memory management model, etc.)\n\n* For a simple example, some ISAs may have an integer multiply instruction, others might instead have a \"multiply step\" instruction that you would have to run several times to multiply, yet others might not have any multiply instruction at all, and you'd have to do a bunch of \"adds and shifts\" to get the same result.\n\n"
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4t3ypa
|
if scotland declared independence now and became un recognised would there be grounds for uk military action?
|
Ok, say the Scottish Government decides it's had enough and officially declares its independence from the UK. It then manages to become a UN member state.
Is Scotland protected by the UN charter that gives nations right to self-determination, or does this not apply in this case? Surely if the Scottish government want independence so bad they can just declare it, and it cannot be opposed as the UN charter says that all nations have a right to independence?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4t3ypa/eli5_if_scotland_declared_independence_now_and/
|
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"This situation can't really happen. The UK is a permanent member of the UN security council so it could veto Scotland's membership.\n\nThe UN's \"right to self determination\" is in the context of colonial possessions. It doesn't mean any and every breakaway state is legitimate in the eyes of the UN.\n\n "
]
}
|
[] |
[] |
[
[]
] |
|
1uivlo
|
Post World War II has there been an Operation like Mincemeat?
|
> [Operation Mincemeat](_URL_0_)
>
> Operation Mincemeat was a successful British disinformation plan during World War II. As part of Operation Barclay, the widespread deception intended to cover the invasion of Italy from North Africa, Mincemeat helped to convince the German high command that the Allies planned to invade Greece and Sardinia in 1943 instead of Sicily, the actual objective.
>
> [It] was accomplished by persuading the Germans that they had, by accident, intercepted "top secret" documents giving details of Allied war plans. The documents were attached to a corpse deliberately left to wash up on a beach in Punta Umbría in Spain.
The name of the dead man was [Glyndwr Michael](_URL_1_).
> The body was released on the condition that the man's real identity would never be revealed.
>
> [...]
>
> In 1998, however, the British Government revealed the body's true identity.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1uivlo/post_world_war_ii_has_there_been_an_operation/
|
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"During the Troubles in Northern Ireland, there was a similarly devious counterintelligence plan against the Provisional IRA, though it didn't involve a dead body.\n\nThe context was that earlier in the conflict, a British Army Intelligence operation called the MRF (for Mobile Reaction Force) had been discovered by the Provisional IRA; in part, this was a group of plain clothes soldiers who had controversially been patrolling Northern Irish streets, occasionally taking pot-shots at people they suspected of being IRA terrorists. A less objectionable facet of their operations was that they were collecting intelligence, partly by driving IRA informants around inside Armoured Personnel Carriers identifying suspects, and partly by surveillance operations like the Four Square Laundry, where plain clothes soldiers operated an ostensibly legitimate business, using a van to pick up unclean laundry from houses in nationalist neighbourhoods and testing forensically for evidence of explosives or firearms. In 1972 the Provisional IRA uncovered an MRF double agent, found out about the MRF, ambushed the Four Square Laundry van, and held a press conference exposing what had happened. This was a considerable success story for the IRA.\n\nFast forward to May 1974, where two prisoners, Vincent Hetherington and Myles McGrogan, were placed on remand, accused of killing a policeman, and asked to be placed in the Provisonal IRA's wing of Crumlin Road prison. They immediately came to the attention of the IRA wing because they weren't members of the IRA, and had had nothing to do with the killing, and so they were interrogated by the other prisoners.\n\nAt first the interrogation seemed plausible - they admitted they weren't IRA volunteers, that they chose the IRA's wing because it would be the safer option, given the nature of the crime they were accused of, and that they were locked up because the RUC had beaten false confessions out of them. However, the IRA members were somewhat suspicious, and the interrogation continued over a period of days. Eventually it worked. Hetherington broke, and finally admitted that he had been approached by the RUC (Royal Ulster Constabulary - the police) over a firearms charge, and had been offered immunity from prosecution in return for becoming an informer. After this, he admitted that the police had hatched a plot for him to poison some of the more senior IRA personnel in the prison, and started naming the names of other informants inside the IRA, McGrogan included. McGrogan, for his part, continued saying nothing, though IRA prisoners found a note from him to Hetherington, threatening to murder him if he squealed. This confirmed the guilt of both Hetherington and McGrogan.\n\nThe prisoners had found another coup similar to that which had outed the MRF. They eagerly sent Hetherington's information up to the leadership, and the army started rooting out the supposed informants. IRA members on the outside (and in the other major prison, the Maze) were interrogated, with all the beatings, mistreatment and torture that implies - and even if a member survived interrogation, he was likely to resent his questioners. The whole army turned in on itself in a witch-hunt where no member could trust any other. Histories generally record this as being one of the worst periods for the Provisional IRA, (though there are other factors involved such as the 1975 ceasefire and the tit-for-tat campaign of sectarian murder).\n\nShortly after the shit hit the fan, McGrogan and Hetherington vanished into protective custody in odd circumstances, and were found not guilty at their trial a few weeks later.\n\nTheir story was all a lie; Hetherington and McGrogan had been planted by British Intelligence, who had coached them to give this story under interrogation in the prison. Whether that was the initial intention, or whether they were going to attempt to infiltrate the IRA first is not clear. The informants named by Hetherington were innocent, if that's the word, and the story had been carefully crafted to match the theories an average IRA member would have of how the British security apparatus worked. Dillon's book suggests that at least two or three people were killed as a result of the revelations.\n\nThe IRA eventually worked out they'd been had, and Hetherington and McGrogan were shot dead, in 1976 and 1977 respectively.\n\nSource: The Dirty War by Martin Dillon\n\n\n"
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Operation_Mincemeat",
"http://en.wikipedia.org/wiki/Glyndwr_Michael"
] |
[
[]
] |
|
4kybr6
|
What was more powerful the recurve or the long bow?
|
This conversation like many others with my roomates started very drunkenly in a bar so please excuse misspellings and/or repetiveness in this question
I argued that the Arab recurve bow while more difficult and time consuming to make is substantially more powerful (especially when it comes to the distance that one can shoot) than the english longbow.
Could I please get get some evidence either proves or disproves my theory that the Arab recurve bow is more potent... thank you very much
Before I get berated for saying Arab instead of a specific country/region I honestly don't know if there was any difference between the effectiveness of different bows so for bonus Internet points could anybody tell me if there was? Thanks again
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4kybr6/what_was_more_powerful_the_recurve_or_the_long_bow/
|
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"Both have similar range and \"stopping power\", the difference is circumstancial:\n\nLongbows are simple bows ie: made from one piece of wood, so they are cheaper to mass produce and maintain/repair, and are more reliable.\n\nRecurve bows are compound bows ie: made from 2 or more pieces that are glued together (usually a combination of soft and hard woods). This gives an advantage in size, so the bow is less cumbersome, and more importantly can be used from horse/camel back, and can be easily holstered when switching to/from melee.\n\nThe downside being the glue would sometimes fail in harsh conditions (humidity, low temps, etc...) so it was less reliable in extreme weather.\n\nBonus for the English archers here would really be the bodkin arrows, they really maximized the ROI of the longbows range",
"Recurves are generally better. Obviously it depends on the poundage of both bows but a recurve will outperform a longbow of the same draw weight.\n\nFirst as far as shooting distance goes.. The farthest distance shot with a Turkish bow was over 800m. The record with an English longbow was less than half that at 340m. [Modern flight bows also 'happen' to look like Turkish bows (with a few extra gizmos on them.)](_URL_2_) There's an anecdote of a Turkish ambassador to England visiting an archery range in the 19th century who amazed everyone with a 440m shot, over a 100m farther than anything any of the English had seen. He then apologized for the poor showing, explaining that he was out of practice and his bow wasn't in good condition.\n\nShooting distance is mostly about speed, so let's look at some speed data. First of all, the arrow speed depends on the energy released by the bow (function of the bow's draw weight) and the mass of the arrow. Because of this, when comparing bows (and arrows) we use a metric called GPP, (**G**rains of arrow mass **P**er **P**ound of draw weight). When you want to compare two bows' arrow speeds, you need to compare at the same GPP. When you collect a bunch of FPS vs GPP data, they [look like this.](_URL_1_). At the same GPP, Turkish bows have a ~7% advantage in arrow speed. Korean bows have a ~16% advantage (this is because they're shot with longer draw lengths than Turkish style).\n\nThe data above shows an advantage in recurves when shot at the same arrow mass, but if you really care about long distance shooting you'll shoot lighter arrows and recurves are much better at that. The minimum GPP you can shoot with a bow depends on how efficient and light the limbs are. If your bow's limbs are bulky and heavy, shooting the bow too fast (because the arrow is so light) will cause the limbs to take damage. You can only shoot a longbow with arrows of around 7GPP and above, most manufacturers void your warranty if you shoot at below 10. Meanwhile because recurve limbs are light, you don't really have to worry about it. [Turkish bows can be shot with ridiculously light 1.6 GPP arrows](_URL_3_) and both Turks and Koreans used [arrow guides](_URL_0_) to shoot very light darts out of their bows.\n\nSo recurves shoot better when in the same conditions but also have the option of shooting lighter arrows than longbows are capable of, to shoot even faster. As for why this is, I'm going to copy paste something I wrote previously on the topic:\n\n > Yes. I mean if by better you mean better ballistic performance, yes composite bows shoot faster, farther and harder because:\n\n > 1. Composite bows have more reflex. That is, a longbow when unstrung is straight, a reflexed bow is bent forward in the opposite way. When a longbow is strung there's almost no tension in the string while a reflexed bow has already been bent and tensed quite a bit just to string it. In terms of shooting, this means longbows only accelerate arrows at the beginning of the shot and not so much near the end as the bow uncoils while a reflex packs a lot of energy throughout the bow.\n > 2. Recurved limb tips improve smoothness at the end of the draw. At the end of your draw when the angle between the string and limbtip is significant, recurved tips maintain a more efficient lever point for the string keeps the rate at which the bow gains weight lower. This again means you're packing more energy just before your final draw length.\n > 3. Horn/sinew are more flexible than longbows and means composite bows can be strained more by being pulled more. A higher draw length affects the energy storage of the bow as much as the draw weight does. While a longbow is typically shot at draw lengths of 28\" (and expert archers in the past would draw to 30\" next to the head), Asiatic draw lengths are typically much higher, about 32\", past the head. Longbows can be made to draw longer but that requires making the limbs longer too (see next point).\n > 4. Smaller and lighter limbs keeps the virtual mass of the bow low. When you shoot an arrow, you're accelerating the arrow's mass but the limbs have to get moving in order to pull the string which launches the arrow. This inertia of the bow is called its virtual mass. The heavier and bigger the limbs, the heavier its virtual mass, and less efficient the bow. More energy goes into getting the limbs moving and less energy goes into the arrow.\n\n > Points 1, 2, and 3 mean composite bows store more energy, point 4 means composite bows use that energy more efficiently. This is true at all load factors, composite bows will generally always out shoot a longbow (given the same draw weight), even with heavier arrows though people generally assume longbows are better at heavy arrow shooting. It's just that their low virtual mass means composite bows are exceptionally good at shooting light arrows fast and far.\n\n > What the longbow does have going for it is that they're easy to make, a good bowyer could turn one out in just a couple of hours and the only maintenance it would need for its lifetime would be some oiling to protect the wood from moisture.\n\n > Meanwhile a composite bow takes months to make, sometimes as long as a year depending on the climate because the components have to be glued and let dry completely before adjustments to tillering can be made. Even after it's finished the the bow has to be shot and heat tillered for about a year, before the bow starts to shoot consistently without the limbs warping and flipping front to back. If the climate is humid, the bow will have to be kept in a special heated box to be able to keep the sinew dry for shooting. You pay for the extra performance with a much higher initial cost and require constant caring for."
]
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|
[] |
[] |
[
[],
[
"http://pds.devpia.com/MAEUL/518/maeul_addboard/42000/41899/HTM75.jpg",
"https://dl.dropbox.com/u/12212152/longbow%20vs%20recurve.png",
"http://www.archeryhistory.com/archers/pics/alanweber.jpg",
"http://www.atarn.org/islamic/Performance/Performance_of_Turkish_bows.htm"
]
] |
|
2ue5yt
|
what would happen in the u.s. if absolutely not a single person voted, i.e. during a presidential election or otherwise?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2ue5yt/eli5_what_would_happen_in_the_us_if_absolutely/
|
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"The candidates can help themselves. They always vote. ",
"The election would be a tie. Different states have different rules on how to decide the winner in case of a tie, but AFAIK all states *do* have some method. \n\nFor the president, if no candidate has a majority of the electoral college then the House of Representatives votes to decide the winner (this happened in 1800 and 1824). \n\nFor state and local elections, there are tie-breaking rules that vary by state. The most common is flipping a coin (really). Others include things like drawing cards or pulling names from a hat (again, really). \n[The Washing Post explains](_URL_0_)",
"My fear is that if nobody voted, there would still be lots of ballots cast.",
"If 'nobody voted' for president, then I assume no senators/representatives voted, either.\n\nIf no candidate gets a majority, it gets thrown to the house of representatives. Since no representative votes, again they can't get a majority, so it goes to the senate, again, no majority, then in THAT case, the President Pro Tempore becomes acting president until SOMEONE votes."
]
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|
[] |
[] |
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[],
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],
[],
[]
] |
||
3y0hwo
|
how is it that heavy drug abuse is able to change facial characteristics so much, even face shape is altered.
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3y0hwo/eli5_how_is_it_that_heavy_drug_abuse_is_able_to/
|
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"Losing body fat leads to sunken eyes, hollow cheeks, etc. There's a lot of fat around the eyes which can be lost. Missing teeth will change the profile around the mouth. Skin blemishes, loss of skin tone/elacticity, will lead to more wrinkles, sores, bruising, etc. Meth is particularly bad for the mouth and malnutrition can do a number on the face of even a non drug user.",
"In most of these caues, it has less to do with the drugs themselves, and more to do with the malnutrition, diseases, injuries, and general harsh treatment drug addicts are likely to face.\n\nThe most noticeable changes will be loss of body face, change in muscle tone, and loss of skin elasticity. Injury can also alter the underlying bone structure.\n\n "
]
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[] |
[] |
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[],
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1cxp1n
|
why does the electrical charge from a detonator seem to slowly travel towards the explosive?
|
Reading online, it seems electricity travels between 60-98% the speed of light in a cable. Why is there a seemingly 'slow' moving glow from a detonator to an explosive.
_URL_0_
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1cxp1n/eli5_why_does_the_electrical_charge_from_a/
|
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"text": [
"Sometimes they use fuses to \"connect\" explosives, it's possible that you saw the light of the fuse burning (there are fuses that can burn pretty quickly) and not the glow from an electrical cable.",
"What you're seeing is shock tube. It's a high speed fuse made of a plastic tube with a thin layer of explosive on the inside. When it is sparked, the explosion carries down the tube but is not powerful enough to blow the side of the tube out. \n\nSource: Explosives Researcher\n\nedit: After seeing just how much that video was slowed down it appears that could be detonating cord too. This would seem to be a strange place to use det cord though. Shock tube is more likely."
]
}
|
[] |
[
"https://vimeo.com/62042628"
] |
[
[],
[]
] |
|
4axgyy
|
why do we swing our arms when we run -- isn't that a waste of energy?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4axgyy/eli5_why_do_we_swing_our_arms_when_we_run_isnt/
|
{
"a_id": [
"d14bhj7",
"d14bwcg"
],
"score": [
11,
2
],
"text": [
"It is a balancing tool. Without doing that we would not be able to run as fast or change direction as nimbly. So it is not a waste of energy at all. ",
"As others have said it's balance. But it actually saves you energy. If you didn't do that then you'd have to correct yourself via the legs at a pivot and that's inefficient"
]
}
|
[] |
[] |
[
[],
[]
] |
||
60pfma
|
how do presidential vacations cost millions of dollars?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/60pfma/eli5_how_do_presidential_vacations_cost_millions/
|
{
"a_id": [
"df87zdo",
"df880j9",
"df887kd"
],
"score": [
4,
2,
2
],
"text": [
"The president's security is understandably very important. Anytime the president decides to travel a lot of moving pieces are involved from teams going out, sometimes months before the actual travel to evaluate all the various locations the president may end up at, scout various routes, and create security plans in the event something goes wrong. All of this cost falls on the government. Then once the travel actually takes place, a LOT is going on. \n\nFirst, the president travels on Air Force One (for long trips) which is not exactly a cheap plane to fly. Potentially hundreds of members of the secret service and other white house staffers that allow the president to do his/her job from any location must also come along.\n\nThen there is the impact on the local infrastructure; when the president is moving, nothing else is. This costs local economies money as highways shut down or businesses in the vicinity have to turn customers away. \n\nIt all adds up and pretty quickly. \n",
"[This article](_URL_0_) is a good read.\n\nThere's a good part of it that starts with a quote from Nancy Reagan who said \"Presidents don’t get vacations — they just get a change of scenery.\" It goes on to explain:\n\n > In the nuclear age, presidents may have only minutes to make a decision that could affect the entire world. They don’t so much leave the White House as they take a miniature version of it with them wherever they go. Some 200 people accompany a president on vacation — including White House aides, Secret Service agents, military advisers, and experts in communications and transportation — to ensure that, while on vacation, the president can do nearly everything he could accomplish in Washington.\n\nAlso:\n\n > The biggest additional expense is the use of Air Force One and the support aircraft needed to haul all the equipment and ground transportation the president needs. The Congressional Research Service estimated that the cost of operating Air Force One is nearly $180,000 per hour. Ultimately, a presidential vacation can cost taxpayers an additional $1 million or considerably more than if the president had just stayed put in the White House. How significant this is within a $3.5 trillion federal budget is something voters can decide for themselves.",
"The president has to travel with extensive Secret Service and a whole slew of other security and communications staff/advisors to protect the president, provide briefings, etc. In addition, there are huge costs to operating Air Force 1, move vehicles and equipment that needs to be accessible at all times. These people all need lodging, food, etc. So think of it as taking 200+ people on a deluxe vacation every time the president goes to Florida for the weekend."
]
}
|
[] |
[] |
[
[],
[
"https://www.washingtonpost.com/opinions/five-myths-about-presidential-vacations/2014/08/15/2aa969c6-2311-11e4-958c-268a320a60ce_story.html?utm_term=.a8e92d365d2c"
],
[]
] |
||
as89qf
|
why do some experaince chest pain due to anxiety but when you get a ecg // blood pressure its fine like there's no reason for the pain but anxiety? what is actually causing pain and why?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/as89qf/eli5_why_do_some_experaince_chest_pain_due_to/
|
{
"a_id": [
"egsgk0u",
"egsgv62"
],
"score": [
3,
4
],
"text": [
"If your breathing really shallow you will feel some pains in your central chest about heart height and it’s from lack of oxygen to the heart there’s a name for it but I forget. \n\nIt’s happened to me from anxiety before. And also when I had some minor energy drink and drug related heart issue ",
"When you have anxiety, your sympathetic system goes up. Have you ever heard of fight or flight? You have palpitations because your heart starts to beat faster. This may be misinterpreted as chest discomfort. "
]
}
|
[] |
[] |
[
[],
[]
] |
||
5zfg5n
|
how or why did 'white noise' get that name? as opposed to other colors like blue or black or green noise?
|
Something I always wondered, and I thoroughly enjoy this subreddit.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5zfg5n/eli5_how_or_why_did_white_noise_get_that_name_as/
|
{
"a_id": [
"dexodi6"
],
"score": [
3
],
"text": [
"Light comes in a variety of colors, and when you have all of these wavelengths together we see it as \"white\" light. The name \"white noise\" is a reference to \"white light\" where a bunch of different sounds all cancel out to the point where no single sound is divisible from the whole."
]
}
|
[] |
[] |
[
[]
] |
|
3puku6
|
Netanyahu said this week that it wasn't Hitler's idea to kill Jews; that was the grand mufti, Haj Amin al-Husseini's, idea. How truthful is this claim?
|
I was under the impression that the holocaust was mostly Himmler's idea. Is that also wrong?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3puku6/netanyahu_said_this_week_that_it_wasnt_hitlers/
|
{
"a_id": [
"cw9kur3"
],
"score": [
2
],
"text": [
"Hi, there was a [thread on this](_URL_0_) very recently, enjoy."
]
}
|
[] |
[] |
[
[
"https://np.reddit.com/r/AskHistorians/comments/3pm4jc/netanyahu_recently_claimed_that_hittler_wished_to/?ref=search_posts"
]
] |
|
15z822
|
What is the least amount of numbers given in a suduko puzzle such that the solution is uniquely determined?
|
Note this does not require the puzzle to be able to solved just that the solution is unique.
|
askscience
|
http://www.reddit.com/r/askscience/comments/15z822/what_is_the_least_amount_of_numbers_given_in_a/
|
{
"a_id": [
"c7r7clz",
"c7r7mxz"
],
"score": [
6,
3
],
"text": [
"The answer is 17; [here](_URL_0_) is an article about that.",
"Interesting question.\n\nFirst of all, if the puzzle doesn't have a solution then there's no meaningful answer. If there are zero solutions, are they unique? The term doesn't make sense in that case. Let's assume there's a solution.\n\nIn that case, I don't know, but I can definitely tell you that it's at least 8. Here's a simple proof - I'll show that any puzzle with at most 7 numbers at the start has more than one solution.\n\nSuppose I have a puzzle with at most 7 numbers at the start, and I have a solution to that puzzle. Then for that solution let me define its n-set to be the 9 squares which are filled in the solution with ns. (I have no idea if there's accepted terminology for this.) Then since there are 7 or fewer numbers at the start, at least two different n-sets are empty. This means that swapping those two n-sets in the solution (i.e. if the empty ones are 1 and 2, you turn every 1 in the solution into a 2 and vice-verse) gives a different solution, so the solution is not unique."
]
}
|
[] |
[] |
[
[
"http://www.technologyreview.com/view/426554/mathematicians-solve-minimum-sudoku-problem/"
],
[]
] |
|
afaxar
|
what causes people to see colors when listening to music?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/afaxar/eli5what_causes_people_to_see_colors_when/
|
{
"a_id": [
"edx0n5q"
],
"score": [
2
],
"text": [
"**Please read this entire message**\n\n---\n\nYour submission has been removed for the following reason(s):\n\n[synesthesia](_URL_2_\n\n\n\n---\nIf you would like this removal reviewed, please read the [detailed rules](_URL_0_) first. If you still feel the removal should be reviewed, please [message the moderators.](_URL_1_?)"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules",
"http://www.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Can%20you%20review%20my%20thread",
"https://www.reddit.com/r/explainlikeimfive/search?q=synesthesia&restrict_sr=on&sort=relevance&t=all"
]
] |
||
zhwo3
|
Does drinking plenty of water actually enhance health?
|
I've always heard that drinking plenty of water is good for your health. How does this work? Does it just facilitate the elimination of various chemicals through urine, or is there more to it?
Of course, if you're dehydrated, more water would help. But would a 60-70kg adult benefit in any way from increasing daily water consumption from 2L to 3L?
|
askscience
|
http://www.reddit.com/r/askscience/comments/zhwo3/does_drinking_plenty_of_water_actually_enhance/
|
{
"a_id": [
"c64q51r"
],
"score": [
10
],
"text": [
"Water is vital to life and therefore extremely important. That being said the body is quite good at adapting and as long as one isn't dehydrated or (and this is pretty difficult to do) over-hydrated to the point where electrolytes are becoming imbalanced, a reasonable amount of water is sufficient and there are no benefits to drinking more than you feel you need (unless a hot co-worker is on the way to the bathroom but they might think you have bowel problems).\n\nThe wisdom of drinking 8 glasses a day has fallen out of vogue, and most recommendations (which vary) are based upon height, gender, exercise levels, diet, and environmental conditions.\n\nThe biggest push for drinking water nowadays is in fighting obesity. Water has zero calories and in over indulgent societies feeling thirsty might be an excuse to down a pint of soda. Sipping water also an excellent way to occupy your hands and mouth as opposed to snacking on chips. Water also helps curb appetite and in a society where an empty stomach means it is time to eat until one feels stuffed to the gills (pun intended), water is indeed an excellent alternative."
]
}
|
[] |
[] |
[
[]
] |
|
491ewb
|
why is it that if i smoke while i have a bad cough i stop coughing for a good 5-10 minutes?
|
Folow up: why is it that i inly feel how painful my lungs are if i smoke cannabis and not tobacco?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/491ewb/eli5_why_is_it_that_if_i_smoke_while_i_have_a_bad/
|
{
"a_id": [
"d0ob6dg"
],
"score": [
2
],
"text": [
"tobacco cigs have chemicals in them that numb your throat, cannabis cigs don't have the chemicals that numb your throat."
]
}
|
[] |
[] |
[
[]
] |
|
1k34f2
|
wrong physics in computer games
|
so whats so hard about having a character in a computer game grab something properly or stap on a step and not slide up the stairs and stuff like that.
im explicitly not talking about water, dust, smoke and all that stuff, honestly i couldnt care less how that stuff looks, as long as they butcher the living hell out of organic material.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1k34f2/eli5_wrong_physics_in_computer_games/
|
{
"a_id": [
"cbkvi9l",
"cbkw0gq",
"cbkyos7"
],
"score": [
17,
5,
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"text": [
"I assume that you're talking about how sometimes your character will be holding something and their hands go \"through\" the item, stuff like that.\n\nThe issue is that the people who animate how the character moves are doing their best to make as few animations as possible. Animation is really expensive and difficult to do, so they try to minimize how much is done.\n\nSo, for example, they'll make one \"two-handed sword\" animation, one \"pistol\" animation, one \"bow\" animation, one \"stairs\" animation, and so on.\n\nThen, the art staff comes in, and says \"alright we designed 100 bows and they all look really cool and people are going to love them.\" The problem is that all the bows are different shapes and sizes, and some of them don't fit the generic \"bow animation.\"\n\nThey *could* fix it, but it's a ton of work, and it costs a ton of money. This should never be a problem in a game that has only a few weapons, but in a game like WoW where there's thousands, it's just not worth it to try to fix.\n\nStairs are really hard, too. What you do when you approach a staircase is that you slow down and adjust your step a little bit so that you can hit the first stair correctly. That's really hard to animate, because animations in games are generally pre-scripted, and adjusting your step like that is pretty on-the-fly.\n\nIn addition, once again, the art staff will make all sorts of staircases with different sized stairs, and the animation team just doesn't have the time to make a special animation for each staircase.",
"Well, it _is_ pretty hard to have things like that. In principle, we could do that, as long as you're fine with not having characters, just pure physics (that currently works well enough). As soon as you introduce human (or humanoid) characters, things become much more complicated, because now you have to simulate all the joints, with the right amount of strength, and that can bend the right way.\n\nWhat makes it hard (i.e. computationally intensive as well as hard to design and program) is that you have all these moving parts that need to work properly with collision detection, are easily controlled by the player on a high level (one press of a key might mean you have to move dozens of joints, oh and it has to work correctly with other commands the player has given and the physics system), and look realisticly human (this one is really hard to get right in the design stage if you want any hint of physical or graphical realism, even without the joint thing).",
"3D Key Frame Animation: \nA 3D model is made up of a collection of points (vertices), which combine together to make triangles, which are then form a face that is painted on with a texture. Storing locations for all these points in different phases of an animation would take too much memory so instead points are assigned to armatures. An armature is basically a bone, and a model usually contains a fare amount of them connected through joints. Each point assigned to multiple bones also has a value assigned to it so it knows how much to move w/ one bone or another. The animator will then move the bones around and create a key frame, which basically just saves the positions the bones are in. These key frames are then what are stored into data and are interpolated between to make an animation. At this stage of development, assets like stairs may not be available to create key frames for, or the game may be action packed which would make things like snapping a model to stairs they just jumped over (so their feet touch properly) too jarring and unrealistic to bother with. \n \nRigid Body (Rag-doll) Rig+ Key Frame Animation:\nTo reduce complex computations in game physics, collisions are usually composed of simple shapes as their bounding/hit boxes. Shapes like boxes, spheres and capsules are generally fairly common for moving objects, and more complex geometry is usually reserved for static or non-moving objects. So when we deal with physics, we typically use these simple shapes. Shapes that aren't allowed to cross into each other (think: solid objects), don't bend, and behave with physics are considered rigid bodies. In simple games with a low budget for memory, a whole character's body has been known to be nothing more then a box or capsule making collisions look odd, or lead to a force field like effect when things collide with you. However in games that are looking to be more realistic, different bones of the body can be masked off with rigid bodies to react to collision. The key frames are then interpolated once more with physics data from the rigid bodies, so you can actually have a character with one foot on the side walk and one on the street and have it look fairly natural. Or you could have someone punch a character and have that punch look more natural and weighty. You could even make for more natural step/stair movement by figuring out where your leg out of snapped to on a stair and interpolate that from your current animation to the step using the physics of the rigid body to make the transition look more natural. The downside of this process is that it takes up more memory then traditional key frame animations, and really only fits realistic settings. If for example you have super human or cartoony characters, it may up being too jarring of a transition still, or lead to real awkward results like having a foot fly up due to the guard rail. \n \nIn short, it can be done, but it doesn't always work for every game's design, and due to the nature of collisions using normally basic shapes, you can still end up with really weird results -- and these results are usually unknowns unless you have good quality assurance. Where as key frame animations are fully created by the animator and thus you know the outcome of the animation, but you can't really word with stairs unless you snap the position/direction of the character, or create key frames to deal with landing on stairs or approaching a set of stairs at different angles -- while still looking natural.\n\nOr you know, some developers are just lazy, or new to development, or need to allocate time to more important areas, or any number of other misc reasons."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
5xwepk
|
in a world where we have devices the size of a deck of cards with enough computing power to launch the space shuttle, why does it still take an hour to update software?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5xwepk/eli5_in_a_world_where_we_have_devices_the_size_of/
|
{
"a_id": [
"deldl9r",
"deldmlk"
],
"score": [
3,
2
],
"text": [
"The task of getting an update to your machine and applying it moves down a very long pipeline. First the data is stored somewhere on a physical hard drive inside a server someplace. The server has to know about your request for the data, access it, send it along the network to the ISP or internet backbone, then the data moves in packets along the internet to your ISP, sent to your area, then to your internet connection drop in your house, then to your modem, to your router, to your computer, stored in your cache, then written to the hard drive, executed by your operating system, your CPU tells the hard drive and RAM which parts to read and store, which files to modify, etc. \n\nThat's a lot of moving parts just to get v1.7 from YourApp and replace v1.6. And the whole process is as slow as the slowest part in the chain. If the server is slow, the whole process is. If your network is congested, if your CPU is slow or working on other tasks. If your RAM is full, if your hard drive has a slow read/write speed or is failing, and on and on. Each piece of the process has a certain speed it can handle data, whether reading it, writing it, executing it, sending it, or receiving it. Any of those points can bottleneck the entire process, and the rest of the data has to wait until that one slow piece finishes what it's doing before handling the next piece. ",
"While that computer is far more powerful, the software running on it is *also* far more complex. That shuttle computer had a few hardwired switches, LED displays and a single megabyte of RAM. Today's computers have 200MB *mouse drivers* and countless thousands of files to check and update when you do an upgrade."
]
}
|
[] |
[] |
[
[],
[]
] |
||
214rog
|
what happens if a couple gives birth to a baby during a flight or a voyage on a plane or a ship? which nationality does the baby assume?
|
In addition, does the baby eventually get to choose, if they have multiple nationalities to choose from?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/214rog/eli5_what_happens_if_a_couple_gives_birth_to_a/
|
{
"a_id": [
"cg9ny77"
],
"score": [
4
],
"text": [
"While the common perception is that where you're born determines your citizenship... this is not exactly true.\n\nYou *can* obtain citizenship based on where you're born -- legally this is called *jus soli*, \"right of soil\" -- but you can, in many countries, also inherit the citizenship of your parents, no matter where you happened to actually be born (this is *jus sanguinis*, \"right of blood\").\n\nThe United States, for example, uses both of these: you are a \"natural born\" US citizen if you're born on US soil, but you can *also* be a \"natural born\" US citizen based on your parents having US citizenship.\n\nAnd sometimes this goes back further -- Ireland, for example, will let you claim Irish citizenship if you had a parent or a grandparent who was an Irish citizen.\n\nCitizenship can also be granted based on other ethnic or religious affiliations; Israel is the best-known example, with its \"right of return\" allowing essentially any Jewish person, born anywhere, to obtain Israeli citizenship.\n\nSo hypothetical \"what if a baby was born in (place that's hard to pin down to a specific country's territory)\" questions are misleading; very often, a baby's citizenship at birth is determined by the citizenship of the baby's parents, not where the baby was born."
]
}
|
[] |
[] |
[
[]
] |
|
343rhv
|
what is the white house correspondents dinner?
|
I heard about it and saw clips from it on the news, but what is it about, and who gets to attend?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/343rhv/eli5_what_is_the_white_house_correspondents_dinner/
|
{
"a_id": [
"cqqzu93"
],
"score": [
6
],
"text": [
"A bunch of journalists from all the different media outlets (CNN, The New York Times, NPR, etc.) are assigned to report on the US president. Together, they make up the White House Correspondents Association. Starting in 1920, they started hosting an annual dinner, and the president and vice-president usually went. The dinner is basically a way for reporters and politicians to hang out for a night. Recently, more high profile celebrities have started to attend, and the dinner has become more famous. The president often delivers a humorous speech, and a comedian usually delivers a roast at the expense of the politicians and journalists in the room. There has been some criticism of the dinners in that it shows how cushy reporters and politicians have become."
]
}
|
[] |
[] |
[
[]
] |
|
19nk4f
|
Could the Universe be a computer simulation? like in the matrix
|
Would we be able to simulate it?
Would it violate the laws of physics?
What if we are in a simulated Universe?
|
askscience
|
http://www.reddit.com/r/askscience/comments/19nk4f/could_the_universe_be_a_computer_simulation_like/
|
{
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3,
2
],
"text": [
"1. Currently no.\n\n2. We don't know - the laws of physics are based on our observations of the universe - any \"universe projector\" would be outside what we can observe and thus not tied to any \"observed\" laws of physics.\n\n3. /r/askphilosophy",
"Here's a fairly accessible [Introduction to Digital Philosphy](_URL_0_) by Fredkin. It describes some early attempts to develop toy physical models in terms of simple computer programs. I found the results rather intriguing, but there are still some issues. Mainly, digital models are naturally discrete. We do not know whether or not space is fundamentally continuous or discrete, but we now know that it's not discrete at least until several orders of magnitude below the Planck scale, which seemed to many to be a natural fit for digital models. Also, In the toy model presented by the paper, space and time have additional structure, and no model with simpler structure has been found which presents the sorts of symmetries and conservation laws we observe in nature. Time, rather that being a simple progression of moments, is divided into 6 phases, and how these phases apply to space depends on whether or not the sum of the spacial coordinates in question are even or odd. Fredkin describes the nature of the model as unknowable determinism. That is, if we are part of a simulation, we cannot take shortcuts and perfectly simulate part of the universe faster than it is naturally simulated. So having complete knowledge of the state of a physical system, and the rules by which it evolves does not mean it's future can be unerringly predicted. ",
"To answer the first part, not even close. Anything non linear is very difficult to simulate and takes huge computers to do simulations of just approximations to reality. Something that seems simple like fluid flow is incredibly complicated to simulate.\n\nI simulate the quarks and gluons, some of the fundamental building blocks of matter. Simulating quarks in a box 0.000000000000001 meters in size requires running for days on the worlds largest super computers. Since an actual cubic meter is made up of 10^3375 of such boxes we have no hope of simulating anything close to our universe unless new techniques of simulation are developed which are millions of times better."
]
}
|
[] |
[] |
[
[],
[
"http://64.78.31.152/wp-content/uploads/2012/08/intro-to-DP.pdf"
],
[]
] |
|
203x99
|
What determines a person's sensitivity to stimuli while they sleep?
|
For example, I can poke my girlfriends face for about 10 minutes while she is sleeping before she wakes up. If anyone so much as breathes near me when I'm sleeping, I wake up frantically. What determines this?
|
askscience
|
http://www.reddit.com/r/askscience/comments/203x99/what_determines_a_persons_sensitivity_to_stimuli/
|
{
"a_id": [
"cfzxluy"
],
"score": [
3
],
"text": [
"There is sensory gating (blocking/decreasing sensitivity to stimuli) during sleep, which varies as a function of sleep stage and how long you've been asleep, especially after the occurrence of the first sleep spindle, and indication that one has entered stage 2 sleep. _URL_0_\n\nThere are also significant differences between individuals, which may reflect differences in continued cognitive activity during sleep. Some degree of cognitive activity does persist into sleep, which is why we can respond differently to different stimuli and adapt to new stimuli, such as moving to a house near an airport and, over a few weeks, no longer recalling being awoken during the night by planes flying overhead. Everybody has some continued cognitive activity during sleep, which appears to be reflected in higher levels of high frequency EEG activity, and some people just happen to have more cognitive activity and high frequency EEG activity."
]
}
|
[] |
[] |
[
[
"http://www.ncbi.nlm.nih.gov/pubmed/7134732"
]
] |
|
1jvtj2
|
What's the claim history on the Senkaku/Daioyu islands?
|
NOTE: This was asked earlier this year, but [it had no relevant responses](_URL_1_).
What is the history behind these islands? What is the argument each side uses to have a claim?
With Japan unveiling a new [helicopter destroyer](_URL_0_) to "better [respond] to various contingencies in waters near Japan" and China warning about "Japan's constant expansion of its military equipment", this situation seems to be heating up.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1jvtj2/whats_the_claim_history_on_the_senkakudaioyu/
|
{
"a_id": [
"cbj2yry"
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],
"text": [
"Apologies if this isn't very exhaustive, but no one has answered yet, so I thought I'd do my best with what I know until a real expert steps up. Feel free to delete this if it's not up to standard.\n\nThe islands are uninhabited and lie some 170km from Taiwan. As such, they are claimed by the PRC and the ROC as well as Japan. \n\nThe Chinese claim begins with historical observation and cartography of the islands by all parties involved. Namely that the islands have been recorded and acknowledged by Chinese sources since at least the 15th century. It was included on several Chinese maps (and at least one Japanese map from the 18th century denotes it as Chinese territory) and marked the Qing Dynasty's frontier with the Ryukyu Islands, after they were annexed by Japan's Meiji administration.\n\nThe islands were formally annexed by Japan in 1895 during the First Sino-Japanese War, claiming them to be \"terra nullius\". In other words, the Japanese claim was that the land was part of no sovereign nation until that 1895 annexation.\n\nChina ceded their claim to Taiwan \"together with all islands appertaining or belonging to said island\" after losing the First Sino-Japanese War in the Treaty of Shinomoseki. However, this treaty was superseded by the Treaty of San Francisco following World War II. The dispute there is whether the treaty's language applies to the disputed islands or not.\n\nJapan argues that China made no objection to the islands being administered by the United States as part of the Ryukyu Islands as part of the Treaty of San Francisco, although China did protest the 1971 hand over of the islands to Japan.\n\nSeveral Chinese maps from the 1950s to the 1970s note the islands as being part of Japan. The PRC deems these maps as erroneous and irrelevant to the dispute. The 1968 discovery of potential oil reserves in the area is what the CIA claims to be the cause of this dispute as a major sticking point in Sino-Japanese relations and the cause of the about turn in Chinese interest in the islands.\n\nThat is not to say that the discovery of reserves somehow \"taints\" the Chinese claim, rather that the dispute would likely have been minor or settled without the added complication.\n\n**TL;DR** The Chinese claim is that they mapped them in antiquity, based a border with Japan off them and they were included in contemporary maps up until the 19th century. The Japanese claim is that no-one lived there, no-one owned them, they were the first to formally claim them and no treaty supersedes that and China never made a major claim until the potential for oil reserves existed."
]
}
|
[] |
[
"http://www.cnn.com/2013/08/06/world/asia/japan-new-warship/index.html?sr=fb080713japanwarship930a",
"http://www.reddit.com/r/AskHistorians/comments/zzn1w/is_there_a_definitive_historical_answer_to_who/"
] |
[
[]
] |
|
5ft9t6
|
is there a way for magnetic energy to be used to create some different kind of energy that could be harnessed as electricity?
|
My line of thinking is that when one puts two magnets they either attract or repulse. This attraction/repulsion causes kinetic energy, I understand. Could there be some kind of way to do this on a larger scale and manipulate multiply magnets to, say, turn a turbine and generate electricity? And if it can be done, wouldn't that create a seemingly unlimited source of power? I understand magnetic materials can lose some of of their magnetic force after time due to deterioration, but I don't imagine it would be too hasty.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5ft9t6/eli5_is_there_a_way_for_magnetic_energy_to_be/
|
{
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"text": [
" > Could there be some kind of way to do this on a larger scale and manipulate multiply magnets to, say, turn a turbine and generate electricity?\n\nNope, sorry. Conservation of energy means you can't get any more out then you put in; the magnets act like springs and not magic energy-generating devices. What you propose can never work.",
"Magnets are how we generate electricity already. What you're describing is a principle we use every day to generate electricity called [Electromagnetic Induction](_URL_0_)\n\nA spinning turbine uses magnets to generate electrical fields which generates the current we use.\n\nUsing magnets to turn a turbine, alternatively, is how an **electric motor** works and requires a power input to operate. That power input is turned into kinetic energy and heat, so as you can imagine, energy is lost in this transaction and so it would have no benefit for further generation.",
"Is there a way of turning magnetic energy into electric? Of course, every generator uses that principle (inducing a current due to changing magnetic flux), from the turbines in power plants to hand cranked flashlights.\n\nAs to\n\n > Could there be some kind of way to do this on a larger scale and manipulate multiply magnets to, say, turn a turbine and generate electricity?\n\nNo. The kinetic energy doesn't appear from nowhere. Magnetic potential energy was transferred into kinetic. \n\n > wouldn't that create a seemingly unlimited source of power\n\nIf you ever create a scheme in which an unlimited source of power is produced, it doesn't work.",
"I think you just described an alternator. Though you are going to need to input energy and what you get out will be less. "
]
}
|
[] |
[] |
[
[],
[
"https://en.m.wikipedia.org/wiki/Electromagnetic_induction"
],
[],
[]
] |
|
4mc54u
|
How popular were burgers and fries before McDonalds and other fast food chains in the '50s?
|
I know Coke, the third part of that holy trinity, was around & popular by the early 20th century, but how popular were burgers & fries? Would someone have regularly eaten them? I remembered that I don't recall any WWII films showing people eating them, but was that due to wartime shortages?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4mc54u/how_popular_were_burgers_and_fries_before/
|
{
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"d3uh6jq"
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"text": [
"So we know that French fries have been around since at least the late 1700s - and we're also pretty sure that they originated in Belgium. Thomas Jefferson had a White House dinner at which \"potatoes served in the French manner\" were served. The Belgian recipe made its way to France, and then over to America, which is how it got the name. Fries were served in the 1800s at American cafes, usually as a snack, but to answer your question (finally), French fries were pretty commonly found on menus with burgers as far back as the 1920s (usually listed as \"French fried potatoes\").\n\nAs for the hamburger, there are conflicting origin stories, but the Library of Congress recognizes Louis' Lunch in New Haven, CT, as the birthplace of the burger. It was a hit when it was served at the 1904 World's Fair in St. Louis. However, when Upton Sinclair published *The Jungle* two years later, the hamburger took a hit - after all, ground beef could have anything in it!\n\nWhite Castle (founded in Kansas in 1921) with its clean interiors, smart-looking cooks, and (most important) on-site grinding, rehabilitated the burger. In fact, White Castle is the inspiration for the other fast food chains that followed. So from the 1920s forward, burgers were pretty popular - you'd find them in diners and roadside stands all over the country.\n\nDuring the Depression, meat was expensive, and so burgers would have a lot of fillers; the onion-fried burger (where 50% of the patty is actually onion) of Oklahoma dates from this period. Others would use crackers, flour, or bread to stretch the meat. Meat rationing at home during World War II further decreased burger consumption (fun fact: during the war, people took to calling hamburgers \"Liberty Steaks,\" another chain in the proud tradition of stupidly renaming things because we don't like the people it's associated with), but for the soldiers? They got the meat, so they got the burgers. It's commonly assumed that American soldiers introduced the hamburger to the rest of the world.\n\nSo, yes, the holy trinity of burgers, fries, and a Coke (or a shake/malt) was firmly in place by the 1920s."
]
}
|
[] |
[] |
[
[]
] |
|
b8qsuq
|
if the sky is blue because the blue light gets absorbed by the atmosphere, and we see by light refracting into our eyes.(i.e blue light hitting our eyes). then how can we see blue things?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/b8qsuq/eli5_if_the_sky_is_blue_because_the_blue_light/
|
{
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"You don't see whatever color something is absorbing. You see whatever color it is reflecting back at you. ",
"The atmosphere doesn’t absorb the blue light, nor does it reflect it, the particulates in the atmosphere scatter the portion of the visible light spectrum with the longest wavelength (which appears blue to us). So while the rest of the spectrum is typically passing straight through the atmosphere and reflecting off of or being absorbed by other surfaces the blue light gets sent in all different directions. So the blue light is still able to pass through and reflect off of other things (making them appear blue) but because there is less being sent towards the earths surface it’s not a common colour in nature . "
]
}
|
[] |
[] |
[
[],
[]
] |
||
47yuwx
|
Mafia in the Soviet Union
|
Does anybody here have information or has read about structured mafia, if there was ever mafia, in the Soviet Union? Maybe something about the black market in Soviet Russia and how the goverment pressured the black market and the Mafia?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/47yuwx/mafia_in_the_soviet_union/
|
{
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"I wrote (part of) my MA dissertation on organised crime in ex-Soviet countries, so I can answer your question.\n\nOkay, before I start, I should say that technically \"Mafia\" refers to the Sicilian organised crime gang... but their fame has caused people to refer to other organised crime gangs as \"Mafias\" and certainly in Russia today people do often talk about \"the Mafiya\" to refer to organised criminals.\n\nThe first major criminal organisation grew up in the Gulags, as essentially a powerful prison gang. It was called the Vor-v-Zakone, which translates as something like \"thieves-with-a-code\". They had a strict set of rules, that most significantly, banned any cooperation with the guards. It also banned drinking alchahol, though it's not very clear how much they actually obeyed the rule. They often refused to do labour. They stole, raped other prisoners (while condemning homosexuals), killed those who opposed them, all the stuff you expect from a prison gang. They also had a complex system of prison tattoos. A cat meant you were a thief, \"only shooting will redeem me\" and pictures of saints and communist leaders were very common. Dots on the hand showed how many years the thief had been in prison. And so forth.\nThey not only operated in prison (where they'd started) but also outside, upon release. Released Vory would work with other Vory as gangs of thieves. \n\n(One note: I'm referring to the whole group as Vory. Actually, Vory were the fully initiated members. Think of it like the Mafia's \"Made Men.\" The ordinary followers were just underlings, while those who'd proven themselves were \"crowned\" as Vory, by other Vory.)\n\nNow, during WW2, with the desperate need for soldiers, many prisoners were allowed to go and fight. Of course, the Vory had sworn not to cooperate with the government, but some went anyway, for patriotism or just as a chance to get out of prison for a while. \nWhen they returned, having defeated the Germans, rather than being praised they found the Vory who stayed behind referred to them as \"Suka\" - bitches. They wouldn't accept them back as Vory.\nSo, the Suka ganged together and fought the Vory in a gang war across the Gulag system. The guards sided completely with the Suka (as they were organised criminals who were willing to work with the guards, so the guards thought they were useful), and often seized improvised weapons from Vory while ignoring the Suka. By the 1950s, the Vory were simply gone, having all either been murdered or absorbed into the Suka.\n\nBut, to many criminals, the Vory became romantic figures. Heroically resisting the government, working together with honour, having all those cool tattoos.\nSo, the Suka (hardly, after all, a complimentary name) essentially became the Vory. Also, as the Gulag system was somewhat reduced after Stalin, they became more significant outside prison.\n\nBut it was in the 70s that the Vory became not just feared, but actually rich and powerful, as they allied with a much more powerful group: the Communist nomenklatura.\n\nIn the 70s, corruption was rife in the Soviet Union. This both was exacerbated by, and exacerbated, the production problems of the planned economy. A lot of factories simply did not get enough of what they needed, and so \"the fixer\" became the most important worker in a factory: someone who could acquire parts. \nIn addition, a flourishing black market grew for a wide variety of products, mostly ordinary (medicine, food, cars). Though of course, it also included prostitutes. \nSome of this was was taken from legitimate factories, but others were produced in secret factories producing exclusively for the black market.\nIn running this black market, the two most important groups were the organised criminals, led by the Vory, and corrupt communist officials.\n\nIt's important to reiterate at this point that the Vory were not a unified organisation like the Mafia you might see on TV. They were simply the leading figures in an Underworld culture. It's a little bit like the Yakuza in Japan: a Yakuza boss is a figure that people in Japan would recognise as an important criminal boss, they probably have tattoos, if their underlings fail they're expected to cut off a pinkie, but it's not like all Yakuza work together as part of one giant organisation (this isn't a perfect example, as the Yakuza were and are organised into a more formalised set of individual gangs than the Vory were).\nAn important and influential criminal would be recognised by other Vories as a powerful figure, get tattoos, and be \"crowned\".\nIt should be said, however, that back in the prisons, it was still a much stricter system, with a very definite seperation between Vories and their followers, and other criminals.\nIt is also important to say though, that while different Vories might each lead their own gang of thieves, they didn't fight that much. The Russian underworld at this time was mostly about running the black market under the noses of the police, with the cooperation of corrupt officials, corrupt police, and corrupt members of the KGB. It wasn't about shooting each other over territory.\n\nNow, we then get to the 80s and Perestroika. Gorbachev allowed people to set up small companies. But that requires money and investment, and in a Communist country, who's been able to build up large amounts of money that's sitting around? Criminals, and their corrupt partners in the Nomenklatura. It's estimated that 90% of the new companies were started with dirty money.\n\nThen, we have the collapse of the Soviet Union. Suddenly, all the factories and state companies are falling apart and available to snap up. At the same time, drugs from Central Asia are available, and people have money to buy it, and are in collapsing social conditions.\n\nIt's here that we begin to see the dissolution of the Vory as a criminal culture. For the Vory, crime was about stealing and selling things on the black market. Money laundering through banks, fraudulent money transfers, setting up shell companies to hide assets, and most significantly, selling drugs, were just not things most of the older Vory really knew how to do. So we have a new generation of bosses, who aren't interested in Vory traditions, and have probably never served time. These were generally just referred to as Authorities.\nSo, as crime changed, the traditional Vory were simply left behind. And in the underworld of the early 90s, that often meant dying in a brutal gang was over territory, fought with military-grade equipment.\n\nNow, in the modern day, they still sort of exist as part of Russia's criminal culture, but there isn't such a divide between Vory and non-Vory. Modern crime is just too fluid. But many Russian criminals have Vory-esque tattoos, and may use the title Vory v Zakone... or not.\nOf course, it's a bit difficult for outsiders to understand exactly what's going on in a criminal underworld, so my understanding of modern crime in former Soviet countries is likely less accurate than the more historical periods.\n\nI don't have the sources on hand, but I can find them if you want to read them.",
"As hateball asked, here are some sources:\n\nJournal Articles:\n\nBoylan, Scott, “Organised Crime and Corruption in Russia: Implications for US and International Law” Fordham International Law Journal, vol. 19 (1999)\n\nRosner, Lydia, “The Sexy Russian Mafia” Criminal Organisations, vol. 10, no 1 (1995)\n\nBooks:\n\nFinckenauer, James, and Waring, Elin \"Russian Mafia in America\" (Pennsylvania: Northeastern University Press, 1998)\n\nGaleotti, Mark, \"Global Crime Today: The Changing Face of Organised Crime\" (Oxon: Routledge, 2005)\n\nGaleotti, Mark, \"Russian and Post-Soviet Organised Crime\" (Hants: Dartmouth Publishing, 2002)\n\nGlenny, Misha, \"McMafia: A Journey Through the Global Criminal Underworld\" (New York: Knopf 2008)\n\nHandelman, Stephen, \"Comrade Criminal\" (London: Penguin, 1994)\n\nPotter, Matt, \"Outlaws Inc.\" (London: Macmillan, 2011)\n\nRobinson, Jeffrey, \"The Merger: The Conglomeration of International Organised Crime\" (New York: Overlook, 2000)\n\nRosner, Lydia, \"The Soviet Way of Crime: Beating the System in the Soviet Union and the USA\" (Massachusetts; Bergin & Garvey, 1986)\n\nSterling, Claire, \"Crime Without Frontiers\" (London: Little, Brown and Company, 1994)\n\nVaksberg, Arkady, \"The Soviet Mafia\" (London: Weidenfeld and Nicholson, 1991)\n\nVarese, Federico, \"The Russian Mafia: Private Protection in a New Market Economy\" (Oxford: Oxford University Press, 2001)\n\nWilliams, Phil, \"Russian Organised Crime: The New Threat?\" (London: Frank Cass, 1997)\n\nWilliams, Phil, and Vlassis, Dimitri, \"Combating Transnational Crime: Concepts, Activities and Responses\" (London: Frank Cass, 2001)"
]
}
|
[] |
[] |
[
[],
[]
] |
|
3kns1k
|
why do countries like saudi arabia destroy so much of their own cultural heritage?
|
It's frustrating to me and I don't understand the reason. I read that 95% of all historical buildings in Mecca have been demolished. It's not like ISIL is doing this: it's the governments themselves. And it's been happening since at least the 1970s. What's the reason?? For something like the tomb of Mohammed's father, I can understand (they don't want pilgrimage / worshipping to such a place), but otherwise I'm lost.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3kns1k/eli5_why_do_countries_like_saudi_arabia_destroy/
|
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"well, im gonna try and say \n\nits alot of power. Alot of people have power unchecked. There isn't alot of respect for historical buildings for what you have mentioned: they do not want worship of a person.\nThing about Islam is that it forbids idol worship of faces. The Saudi authorities love to strictly (i say veryvery strictly) to the word that there should be no sort ofimage of anyone to worship. Thats fine to keep everybody worshipping the one Allah.\nOh another hand, the power of influence stays with the royal family. Think about it. They have the power and get rid of any chance of what they think is doubt so they keep a strangle hold on it.\n\nThats the two majro things i have to say.",
"Saudis arent destroying *their* cultural hertiage, they are strengthening their perspective of Islam. Im assuming you are Christian; Islam has a much higher divide among sects then other religions. Like how catholics and protestants hated each other and fought wars against one another, thats pretty much where Islam is right now in the middle east for a large number of reasons. Saudi Arabia is a **very** conservative Sunni majority, plus being arguably the most powerful nation in the Middle East, and having a stable government for nearly 100 years. They have an almost perfect set up to influence the direction of their religion for many generations to come, so thats what they are doing. And they own the land to the holiest city to their people. Think of them like America right out of WWII, they are on top of their game and dont show signs of having it any other way. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
351nmj
|
Can an electromagnetic wave inside a Faraday cage go out?
|
(everything in the title)
|
askscience
|
http://www.reddit.com/r/askscience/comments/351nmj/can_an_electromagnetic_wave_inside_a_faraday_cage/
|
{
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"text": [
"Only insomuch as the Faraday cage is imperfect. For example, there will be some microwaves leaving your microwave through the little holes, but on the inside it's strong enough to cook your food and on the outside it's less than what gets emitted by your cellphone.",
"For the most part, no, electromagnetic waves in a Faraday cage cannot get out. They are trapped and bounce around until they are absorbed and turned to heat.\n\nBecause of wave tunneling, a small amount of electromagnetic waves always leaks out of a Farady cage. The thicker you make the walls of the cage and the more conductive you make the walls, the less leaks out. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
4crqpk
|
if i file a restraining order against someone, what prevents me from "abusing" the order aka "trolling" the person by following them where they go?
|
So, if I found out the "restrained" was going on vacation, what stops me from boarding the same plane and forcing him to disembark?
If he's leaving for work, couldn't I stand in the middle of the street and block his driveway?
What stops me from follow him around and abusing my restraining order?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4crqpk/eli5_if_i_file_a_restraining_order_against/
|
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"text": [
"Others have explained it more seriously but I'll just add that there's typically very serious and obvious reasons someone files a restraining order against someone. If someone makes you afraid for your life every time you're near them it's not a smart idea to intentionally seek them out and assume a piece of paper will make them afraid of you.",
"Probably getting arrested and going to jail for abusing your restraining order. Being on their property is pretty deliberate. And ticket sales and flight records would indicate you shared a flight on purpose.",
"In many states if you intentionally go near them you are violating the no contact order as it goes both ways. You would be subject to the criminal penalty for intentionally violating a NCO or restraining order. ",
"The subject of the restraining order would quite reasonably approach the court to complain. Obviously in the first few instances it would probably be dismissed, but it wouldn't take long before it became obvious you were abusing the system.\n\nWhat action the court would take, I couldn't say.",
"Cop here:\n\nThe restraining order will usually specifically say not to, or you risk invalidating it.\n\nAlternatively, the restraining order may essentially work both ways, so you'd be in violation.\n\nGenerally if the situation occurs where you show up to a public place they already are, they are not obligated to leave as long as they don't harass you.",
"In most jurisdictions, if you voluntarily break the restraining order yourself, it is nullified. The TRO/NCO goes both ways. They're not allowed to come within a certain number of feet of you, but you're also not allowed to go near them. Nor are you allowed to harass them or file false reports. You'd be the one subject to jail or fines if you did such a thing. Also, if the situation occurs where you're both in a public space unintentionally at the same time, there would only be an issue if they did something that could be construed as harassment. "
]
}
|
[] |
[] |
[
[],
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|
548fz8
|
Why do people think that everything is contained within π? Where did this idea come from and is there any logic or proof for it?
|
For the statement that everything is in π to be true, this would also mean that π is in π. A sort of π'ception would occur creating a repeating number making π a rational number. This raises additional questions:
*Is π definitely a irrational number?
*Is there any proof that it is?
*How do we know that π doesn't?
*How do they even calculate π?
|
askscience
|
https://www.reddit.com/r/askscience/comments/548fz8/why_do_people_think_that_everything_is_contained/
|
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"text": [
"Yes, pi is irrational, its been proven. A. number is rational if and only if its decimal expansion is terminating or is eventually periodic, meaning that finitely many terms in the expansion repeat periodically. For example, 0.13361451678678678678678... is an example of a rational number with an eventually periodic decimal expansion i.e. 678 keeps repeating.\n\nI am not sure what is meant by pi containing itself. But if you mean that the digits repeat as in say 3.14153141531415... then it would be rational since its releating as i have explained above. But ofcourse since we proved that pi is irrational, it follows that this can not be the case.\n\nThe claim that pi contains everything comes from the belief that pi is a [normal number](_URL_1_). It is not proven as of yet that pi is a normal number, but it is very likely to be the case. In fact most irrational numbers are normal; most here meaning that the normal numbers are uncountable, wheras the non normal numbers are countable. Countable means having the same cardinality of the natural numbers, and uncountable here means cardinality greater than natural numbers (in this context its the cardinality of the real numbers)\n\nThere are [formulas](_URL_0_) that have been found and we use them to calculate pi. Naturally some of these are more efficient than others. I am not sure which one is used to calculate pi though.\n\nEdit: formatting",
"[Here](_URL_2_) - [are](_URL_0_) - [a](_URL_9_) - [bunch](_URL_8_) - [of](_URL_4_) - [relevant](_URL_5_) - [threads](_URL_10_) - [from](_URL_1_) - [the](_URL_6_) - [search](_URL_3_).\n\nAlso in the [FAQ](_URL_7_)",
"π is an irrational number, there are [proofs](_URL_0_) of this. Expansion of π in any integer base is infinite and not repeating. However, the property of finding anything in π you mention, requires more than simple irrationality.\n\nThere are numbers, called normal numbers, in which every digit has the same chance to appear, every pair or larger combination of digits has the same chance to appear as other combinations of the same size. In such case, as we look at ever larger expansions of the normal number, the probability of finding any finite number in its expansion approaches 1. So are nearly certain to find any finite expansion of π further inside π. But the infinite expansion will not repeat as π is irrational.\n\nThe idea that π is a normal number seems to be true based on the analysis of the digits already calculated, but there is no proof that π is normal or not.\n \nUnfortunately I don't have time to explain the process of calculating the digits of π."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/List_of_formulae_involving_%CF%80#Efficient_infinite_series",
"http://pi314.at/math/normal.html"
],
[
"https://www.reddit.com/r/askscience/comments/2tlkdl/is_it_true_that_pi_can_contain_every_possible/?sort=top",
"https://www.reddit.com/r/askscience/comments/1binaj/if_pi_contains_everything_does_it_also_contain_pi/?sort=top",
"https://www.reddit.com/r/askscience/comments/2xc3eb/if_pi_has_an_infinite_number_of_decimals_and/?sort=top",
"https://www.reddit.com/r/askscience/search?q=pi+every&restrict_sr=on&sort=relevance&t=all",
"https://www.reddit.com/r/askscience/comments/l57eh/how_infinite_is_pi/?sort=top",
"https://www.reddit.com/r/askscience/comments/1e6q7t/sometimes_people_claim_that_digits_in_the_pi/?sort=top",
"https://www.reddit.com/r/askscience/comments/41yn10/i_know_pi_is_infinite_but_is_there_any_point_at/?sort=top",
"https://www.reddit.com/r/askscience/wiki/maths/pi_every_combination",
"https://www.reddit.com/r/askscience/comments/12jfta/if_pi_is_an_infinite_number_nonrepeating_decimal/?sort=top",
"https://www.reddit.com/r/askscience/comments/3nqxim/does_pi_really_contain_every_combination_of/",
"https://www.reddit.com/r/askscience/comments/16lry8/does_pi_necessarily_contain_every_possible_finite/?sort=top"
],
[
"https://en.m.wikipedia.org/wiki/Proof_that_π_is_irrational"
]
] |
|
5vlacb
|
when teenagers' voices break, do they simply get deeper or are there other changes that take place?
|
Could I in theory use Audacity to shift the pitch in my voice and have it sound like it did before puberty? (ignoring changes to vocabulary and speech patterns of course).
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5vlacb/eli5_when_teenagers_voices_break_do_they_simply/
|
{
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"de3koix"
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"score": [
2
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"text": [
"In addition to the vocal chords 'stretching' and thickening during puberty as a result of - but not completely limited to - an increase in testosterone, the tone and phonic patterns also change over time. \n\nThis is why even if you can't physically see someone, such as when you're on a phone call with a new person, you can generally estimate rather closely the age of that person just by the tonality and character of their voice - most of the time this association happens completely subconsciously. "
]
}
|
[] |
[] |
[
[]
] |
|
895qxt
|
explain the black scholes model, and where it comes from.
|
Curious about how the Black Scholes model was created, and a solid understanding of how it works to price options. Not a finance major.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/895qxt/eli5_explain_the_black_scholes_model_and_where_it/
|
{
"a_id": [
"dwp425l"
],
"score": [
5
],
"text": [
"Is this about Paul Pogba?"
]
}
|
[] |
[] |
[
[]
] |
|
2rrysd
|
jumping from a building, is there a landing position that would get one to survive?
|
I couldn't sleep last night and when that happens my mind always think about random stuff and this came up. Say one jumps from a building - like World Trade Center for example - is there any landing position that would make them survive? I think landing belly-down or belly-up would seriously damage your head and spine so I think it's out of question. The only one I came up with was side landing, like landing on your arm with your hand under your head - like normal sleeping position - I think that would be the most effective but I'm not sure if it would save the person.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2rrysd/eli5_jumping_from_a_building_is_there_a_landing/
|
{
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"cniox0c"
],
"score": [
4
],
"text": [
"I'm not sure about the math behind it. But I was told by a sky diving instructor that there is a way to position yourself that only your legs will take the impact. You'll be paralyzed for the rest of your life. But its better than nothing."
]
}
|
[] |
[] |
[
[]
] |
|
2pmm0c
|
why do most flying insects (flies, bees, etc) become so lethargic and slow when they're indoors for a while?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2pmm0c/eli5_why_do_most_flying_insects_flies_bees_etc/
|
{
"a_id": [
"cmy5at2"
],
"score": [
9
],
"text": [
"They wear themselves out banging against the glass."
]
}
|
[] |
[] |
[
[]
] |
||
3dibgy
|
What is the purpose of the investigation of History? Can we really "learn from history?"
|
Should we investigate history to know our place in it? To learn from it? Is it a goal worth pursuing in itself?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3dibgy/what_is_the_purpose_of_the_investigation_of/
|
{
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"text": [
"I personally think that history is a very worthwhile pursuit. I am currently taking a degree in history and through widening my knowledge about the past, I feel that I've gained massive perspective about the way people think and the way people express themselves in the way that they do. ",
"[Here's something written by the American Historical Association as a start](_URL_0_)\nOne important point is in my opinion that we need history to understand and be able to solve conflicts of the now, for example what lead to the development of fundamentalism in the Middle East and what lead to the temporary demise of democracy in the years leading up to WW2."
]
}
|
[] |
[] |
[
[],
[
"https://www.historians.org/about-aha-and-membership/aha-history-and-archives/archives/why-study-history-%281998%29"
]
] |
|
1l2y7m
|
How soon is too soon to excavate for archeology purposes? And at what point does the act of grave robbery become archeology?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1l2y7m/how_soon_is_too_soon_to_excavate_for_archeology/
|
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"I really like this question, and I hope others will add perspectives from other fields. This has been a serious issue for indigenous communities in North America for a long time, and it's arisen over and over again because many indigenous communities set a very different standard for distinguishing between grave robbing (or simply disrespecting ancestors) than scientists. There's an excellent documentary about indigenous protests over the [Dickson Mounds Museum in Illinois](_URL_3_) whose name I can't recall, in which a white archaeologist talks about his previous work doing digs of Native American burial sites. During those digs, contemporary tribal members often asked him whether he was on his way to dig up their aunts or grandmothers. The idea that these centuries-old bones would have such immediacy for these communities had never occurred to him. Maybe the [Paris catacombs](_URL_1_) aren't the most representative example of Western relationships with the dead, but the degree of cultural dissimilarity between the protests at Dickson Mounds and the tourism at the catacombs is striking, at least.\n\nA lot of indigenous protests of museums like Dickson Mounds occurred around the passage (in 1990) of [NAGPRA](_URL_0_) -- the Native American Graves Protection and Repatriation Act. That legislation came at the tail end not only of otherwise well-meaning archaeologists (like the one above) digging up indigenous peoples' bones, but a much creepier history of displaying the bones and bodies of very recently deceased people in museums as well. NAGPRA was established to restore many of those bones and artifacts to native communities. NAGPRA-related issues can be pretty contentious -- particularly when scientists or archaeologists feel there's some important information to be gained from the material in their collections, or in the ground. At times the debates are clear-cut and easy to resolve; other times, much less so.\n\nJohn Troutman's *Indian Blues* quotes a story from this earlier, creepier history -- which was extensive -- from a Creek-Cherokee musician named Tsianina Redfeather Blackstone, who encountered one anthropologist in 1916:\n\n > I noticed him looking occasionally at my head. With no attempt at flattery, he said, \"You have made so much out of your life in so short a time, and your head is so beautifully shaped, I would consider it a great contribution to the history of your people and archaeology if you would let us have your head when you depart for the Happy Hunting Ground.\" I made no reply, but inside I didn't feel so good. He frightened me, and I had a secret fear of having my skull on display for all to see. Imagine my relief when my beloved friend left for his Happy Hunting Ground before me.\n\nThe artist James Luna staged a kind of protest of that history -- and of the presentation of indigenous cultures as static and extinct in museums in general -- in his 1986 [*The Artifact Piece*](_URL_2_). It was a kind of performance in which he laid inside a museum case for hours and encouraged visitors to look at his live, still body. It's a fascinating story overall, I think, and I'd be very interested to hear whether there are analogs elsewhere.",
"Depends what you want to do. I know some people who want to start diving and monitoring the wreck of the tall ship *Bounty* that sank earlier this year. Two people died on that wreck and may still be aboard (won't know till someone locates the wreck and has a look). I agree 100% with the people who want to dive the wreck. This is an unprecedented chance to observe site formation processes in action. To be quite frank I would have been ok with starting archaeological monitoring the next day after she sank if someone knew where the wreck came to rest.\n\nThe University of Arizona has a project where they send archaeologists into landfills. There they excavate and examine trash to answer the same sorts of questions about the modern world we often ask of the ancient ones. How much of what gets eaten, what do we throw away, etc... So they are working on modern materials. \n\nI think though you are more interested in the excavation of human remains. That's going to be a more gray area. See the thing about archaeology is that chain of ownership is really important in drawing the line about what we can and can't excavate. Speaking generally, archaeologists deal with objects that have been abandoned or lost. If something can be demonstrated to be still owned than I need the permission of the owner to excavate or examine it. For example when I worked the *USS Huron* mapping project my school conducted last year we needed permission from the US government to drill and place sensors on the wreck. If someone finds, say an historic rubbish mound on their property then I need their permission to excavate it since they own the land.\n\nSometimes the government can override the land owner. For example in the UK any treasure over a certain amount (I think it's 50 coins) is considered a hoard and is claimed by the crown. The state can then send in archaeologists to excavate. Sometimes outside groups can also exercise a claim. In the US we have [Native American Graves Protection and Repatriation Act ](_URL_0_) which gives Native American tribes certain rights and privileges when the body of one of their own is discovered. In the case of human remains the local police are also going to have a claim if the body appears recent enough that it is within their statute of limitations to investigate as a homicide. In the case of say, a graveyard, you are going to need to demonstrate to the state either abandonment or establish contact with descendents and secure permission. Chain of ownership has no practical limit on time frame as we see with NAGPRA. \n\nIn summary, time limit is not really important. Status of existing legal claims of ownership against the object as what really limit what we can investigate. ",
"Hardest question first: at what point does grave robbing become archaeology?\n\nI would direct you to the code of ethics to the archaeological association of the region of interest, as well as the laws established by the government, e.g. NAGPRA like someone has mentioned.\n\nAS an example: Society for American Arcaheology (SAA) [Code of Ethics](_URL_1_)\n\n\n[Another link from the SAA that might help you further understand the issue]\n(_URL_2_)\n\nIn archaeology dealing with graves is seen as an act of respect, and nowadays most archaeologists would not even dare to touch a grave unless there is expressed consent and the laws of the region as well as the wishes of the community have been addressed. This is done in conjunction with experts in the area. Where I do research any burial we find, even though NAGPRA does not cover it, is informed to the Forensic Institute where their expert will come, visit the site, assess the situation (tropics do terrible things to a skeleton so we need to make sure it is not a recent body...) and then after a (spoken) approval it is exhumed by a Bioarchaeologist or someone with a similar background/experience.\n\nSince the law in the region that I study states that anything found underground of archaeological value is the island's patrimony everything is kept by the government (private land is tricky but not as straightforward as it is in the US). Hence, there is no robbing. Archaeologists do not keep anything, unless they are doing analysis and the government gives them the permit and there are different storage facilities that the government keeps track of.\n\n\n--------------\n\n\nAs a loose definition, archaeology is from a generation ago and backwards. This is just a loose definition and I've heard it first hand from many colleagues, but it is not a set rule. Many, however, do similar research in fields such as [Garbology](_URL_0_) that would cover up to present time.\n\n\n------------------\n\nI invite you to /r/AskAnthropology if you want to ask more Archaeology related questions, as well as /r/Archaeology.",
"I went to my book shelf for this because I know there was an answer is one of my forensic anthropology books. This is a question that overlaps into forensic anthropology and also into archaeology.\n\nFlesh and Bone: An Introduction to Forensic Anthropology by Myriam Nafte Page 30, 32\n\n**Are the Human Remains Ancient, Historic or Modern?** *\"If the remains have been identified as human, it is critical to determine their age. Were they deposited recently, a hundred years ago, or three thousand years ago? Many clues may indicate whether remains are ancient (in a North American context, approximately 500 years old), historic(approximately 100 to 500 years old) or modern (within the last 50 years)...If the remains are found to be modern they are of forensic significance. This is based on the premise that the deaths of all individuals which occur in the United States and Canada withing a particular time period must be accounted for. Hence, their remains- intact, decomposed or skeletonized- are protected under the law, prior to and during subsequent investigation. A legal investigation into the identity of the individual, the possible time, place and cause of their death, and the events leading up to the deposition of their remains can then proceed.\"*\n\nHowever, forensic anthropologists and archaeologists often work on crime scenes together. One of my mentors go abroad and retrieves solider remains from the variety of wars we have been in. The military focuses more on recent wars because it is more likely there is a living family to return the remains to. Both are also used in cases of violation of human rights (mass graves), large sites of the dead (airplanes for example, and even just used for their data recording methods.\n\n\"Grave robbing\" is basically a term used by people who have a moral feeling against disturbing the dead. All crime scenes must disturb the dead and has it's obvious uses. When it comes to graves it's often a case of needing information. Be it a more recently burial that is disinterred for forensic information or a much older burial for historical and life style information.\n\nThe entire purpose is information. There are a slew of varying ethical opinions involved. But in short: modern or ancient it's done to answer the questions of who, what, why and when as well as some other questions of lifestyles long past. The amount of insult to the issue mostly seems to be a combination of cultural or the number of insulted living relatives.\n\nThere is a good deal of context involved. \n\n\n-Other book I pulled:\n\nSilent Witness, by Roxana Ferllini and forward by Dr. Cyril Wecht for information on joint efforts of archaeologists and forensic anthropologists on modern and less modern digs.\n\nEdit: format\n\n\n",
"The answer is it depends on what kind of archaeologist you are, what type/kind of research question you're asking, and the immediate reality of the resource. \"Historic\" archaeology begins 50 years after a resource was created (there are exceptions), and 75 years on human remains (here in Florida, but your results will vary). \n\n\"Grave-robbing\" is a cultural construct and depends on your worldview and perspective. It generally insinuates the improper (e.g. non-systematic or scientific methods of extraction with no documentation), unlawful acquisition of artifacts or other goods of cultural patrimony with the intent to either personally keep in a private collection or sell for profit. What little data, if any, gathered will not be shared. \n\n > In summary, time limit is not really important. Status of existing legal claims of ownership against the object as what really limit what we can investigate.\n\nTime limit is important, but it has the potential to not be in some circumstances. I'm thinking Section 106 or recent historical past that's endangered. \n",
"I hope this is ok for the sub, but I'm going to answer from the legal perspective, because that's my area of expertise.\n\nFrom a legal standpoint, *technically*, in many states the answer is \"never.\" For example, NY Public Health Law section 4218 states that opening a grave is a Class D Felony. There is no \"time limit\" in the law - technically a 1000 year old grave would be the same as a 2 day old grave.\n\nIn addition, [over 30 U.S. states have laws that specifically deal with aboriginal or native remains, with varying mandates on what must be done, and \"how long\" they must have been there.](_URL_0_)\n\nI'll let the historians and archaeologists here answer the philosophical and moral questions - there are certainly myriad.",
"You could also hit up /r/AskAnthropology. They need more questions. ",
"I started thinking about that when I saw the mummy exhibits at the British Museum. I realized how morbid it was to see the corpses of long dead human beings on display, including a very well preserved body without bandaging. Doesn't seem it should ever be right to put them on display, even if digging them up to discover them and learn from them does help civilization remember its history. After the research is done, just to respect individual cultures it seems proper to re-inter all that has been dug up."
]
}
|
[] |
[] |
[
[
"http://www.nps.gov/nagpra/",
"http://en.wikipedia.org/wiki/Catacombs_of_Paris",
"http://www.cfa.arizona.edu/are476/files/luna.htm",
"http://articles.chicagotribune.com/1991-11-26/news/9104170045_1_native-americans-jim-edgar-archeologists"
],
[
"http://www.nps.gov/nagpra/mandates/25usc3001etseq.htm"
],
[
"http://itech.fgcu.edu/&/issues/vol2/issue2/garbology.htm",
"http://www.saa.org/AbouttheSociety/PrinciplesofArchaeologicalEthics/tabid/203/Default.aspx",
"http://saa.org/AbouttheSociety/Publications/ArchaeologyandYou/Chapter4PreservingthePastfortheFuture/tabid/1010/Default.aspx"
],
[],
[],
[
"http://www.fofweb.com/History/MainPrintPage.asp?iPin=ind1244&DataType=Indian&WinType=Free"
],
[],
[]
] |
||
ipc3l
|
Does flying an airplane counter to the rotation of the earth increase the planes speed, decrease the duration of the flight or allow the plane to reduce it's power to essentially cross the same distance and time with less fuel to burn?
|
askscience
|
http://www.reddit.com/r/askscience/comments/ipc3l/does_flying_an_airplane_counter_to_the_rotation/
|
{
"a_id": [
"c25kaxq"
],
"score": [
12
],
"text": [
"Unfortunately no. The earth's atmosphere is actually rotating along with the rest of the earth, so there is no shortcut to be gained this way.\n\nIt seems like this is a fairly common misconception as a lot of west- > east flights are shorter than their east- > west counterparts. This has to do with the prevailing winds (for example: the jet stream when crossing the atlantic) rather than the earth rotating beneath the plane."
]
}
|
[] |
[] |
[
[]
] |
||
m7ofy
|
Can a sane mind be turned schizophrenic?
|
askscience
|
http://www.reddit.com/r/askscience/comments/m7ofy/can_a_sane_mind_be_turned_schizophrenic/
|
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"text": [
"Follow up (more of a definition question): what is the state of mind called where you've truly convinced someone they're insane?",
"There is a genetic code directly linked to Schizophrenia. About 1% of the general population have the genetic code itself. These 1% minds also will need a triggering event to act as a catalyst in \"priming\" the genetic code, ultimately activating the Schizophrenia.\n\nIf a person is not born with the genetic code, then no... a sane mind cannot develop schizophrenia. But, there are many many other behavioral and personality disorders that a sane mind CAN develop over time; but, schizophrenia is not one of them unless you have the predetermined code to do so.\n\nSource: Psychology Major ",
"Follow up (more of a definition question): what is the state of mind called where you've truly convinced someone they're insane?",
"There is a genetic code directly linked to Schizophrenia. About 1% of the general population have the genetic code itself. These 1% minds also will need a triggering event to act as a catalyst in \"priming\" the genetic code, ultimately activating the Schizophrenia.\n\nIf a person is not born with the genetic code, then no... a sane mind cannot develop schizophrenia. But, there are many many other behavioral and personality disorders that a sane mind CAN develop over time; but, schizophrenia is not one of them unless you have the predetermined code to do so.\n\nSource: Psychology Major "
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
3vchhp
|
what exactly are the "stricter" gun control laws people propose and how would they be enforced?
|
Seems relevant once again. I don't own a gun and don't have a strong opinion either way, but there are unfollowed laws against shooting people, so the pragmatist in me wonders what these gun laws would be and why people think they would be effective.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3vchhp/eli5_what_exactly_are_the_stricter_gun_control/
|
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"text": [
"There are a few different levels the law could be:\n\n- Banning certain types of weapon (eg Automatic Rifles), under the theory that you don't need an M4 Carbine to protect yourself\n- Banning all guns (as is done in most of Europe) apart from a few people with special permits\n- Banning guns in public, eg you can have them at home but as soon as you take them out of your home then you're breaking the law (ie anyone taking a gun down the street is assumed to be using it for illegal activities)\n- Much tighter regulation, control, and registering of guns, with much stricter background checks: guns would still be legal, but it would be harder to get one and much better tracked.\n- Much tighter regulation in terms of keeping guns and the ability of the police to ask you to prove yours is legal. So, for example, if someone gets hold of your gun and uses it, **you** are responsible too, for not keeping it safe.\n\nAs to how they would be enforced... the police would enforce them, how else?\n\nWhy do people think they would be effective? Well let's compare two countries that are quite similar in many ways.\n\nCountry | Population (approx) | Gun control | Number of mass casualty shootings (4 or more casualties) in the last 1066 days \n---|---|----|----\nUSA | 300 million (5x larger) | Very little | 1052 (shootings, with 1,347 deaths and 5164 total dead/injured)\nUK | 60 million (1/5th of the size) | Very tightly controlled | 0 (Yes Zero, that's not a typo)\n\nIs everybody clear?\n\nI know the USA and UK aren't **the same**. And I know the USA is **5x larger**. But the UK has had **NO, ZERO, ABSOLUTELY NONE** mass shootings in the last **5 years**. While the USA has had **OVER ONE THOUSAND** in **less than 3 years**\n\nThat's not just a cultural difference, a statistical error, or a bit of a difference because America is bigger... that's an absolutely astonishing difference. That's over **4 thousand** people injured or wounded in America, when we should expect roughly **900** in the UK if the population was all that mattered, yet the UK has had **none**. And I've yet to hear even a half convincing argument that shows why there has been such an incredible difference.\n\n_URL_0_\n\nNow let's wait for the \"But we like guns\" downvote brigade...",
"The first ones discussed are things like stronger background check rules. Currently, they differ from state to state, and there are loop holes for things like gun shows, where people can buy guns without a background check... so close those loopholes and have a national database that checks against things like criminal records, mental health, no-fly lists. There can also be limitations on assault weapons. Limits on types of ammunition available. Other things like registering guns and licensing owners.",
"I dunno, I like [the current laws](_URL_0_).\n\nNo weapons shorter than 75cm. No semi autos with > 7 rounds without endorsement. Required licensing and registration. Required safe, literally in a safe storage. No open or concealed carry.\n\n",
"I don't understand the argument that people have which is usually along the lines of 'people are breaking the law by murdering people so how will more laws help'. The evidence is plain to see in all of the countries were guns are banned. Fewer guns mean less chance for gun violence. \n\nThe problem is is that gun culture is so ingrained within America that it would take a few generations for the laws to really kick in. This is all a mute point though, after all of the shootings and deaths, the US won't even allow more stringent background checks, never mind an outright ban. "
]
}
|
[] |
[] |
[
[
"http://www.theguardian.com/us-news/ng-interactive/2015/oct/02/mass-shootings-america-gun-violence"
],
[],
[
"https://en.wikipedia.org/wiki/Gun_politics_in_New_Zealand#Current_firearm_law"
],
[]
] |
|
5cwhjd
|
why is nintendo always in short supply of the consoles
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5cwhjd/eli5_why_is_nintendo_always_in_short_supply_of/
|
{
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"text": [
"A short supply can create a bigger demand and hype.\n\nThey are either doing it deliberately to cause a stir for publicity or they genuinely don't think they will sell that many in that time frame.\n\nAlternatively it could have nothing to do with either and the manufacturers could be at fault. "
]
}
|
[] |
[] |
[
[]
] |
||
1r8bnx
|
why do i always feel greasy after falling asleep on airplanes?
|
It seems like every time I fall asleep on an airplane I wake up feeling gross. Why does this happen? Why is it only if I fall asleep?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1r8bnx/why_do_i_always_feel_greasy_after_falling_asleep/
|
{
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"I think it has to do with the recycled air in the cabin.",
"I get this way any time I sleep in clothes, regardless of the environment. I've also always wondered.",
"My husband works for an airline. He told me once that the new Boeing Dreamliner is made from a new material that allows up to ~12% humidity in the recirculated air, allowing for less dehydration of your skin and eyes on long haul journeys. I think maybe the greasy feeling has something to do with the lack of humidity in the air. The materials that planes are made from can have dramatic reactions to variable humidities and altitudes so a very low humidity is desirable. That's why the Dreamliner is a big deal to regular long haul travelers (or it will be once they are all up an running). Hope this gets you closer to an answer."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
1h2g6z
|
Why did Mycenaean plate armor fall out of use?
|
I've been reading a lot about ancient warfare lately, and the pictures in these books generally show 2 flavors of Mycenaean troops. The first one is a soldier wearing only a loincloth and helmet, wielding a spear and a peanut shaped hide shield. The second kind I find more interesting. They are [heavy](_URL_0_) troops wearing bronze [plate](_URL_1_) armor. They use long pikes and are sometimes depicted with large rectangular shields. Often they ride in chariots. My question is why did the plate armor fall out of use? It looks as though it would do a very good job of protecting its user from both missiles and other attacks. Was it because of expense or did it encumber its user too much or what?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1h2g6z/why_did_mycenaean_plate_armor_fall_out_of_use/
|
{
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"text": [
"Mycenaean warfare, as Snodgrass notes, is pretty much entirely unknown to us. Snodgrass theorizes that there may have been two phases of Mycenaean warfare, coinciding with the Shaft Grave period and the Beehive Tomb period within Mycenaean ruins. \n\nAccording to Snodgrass' reckoning, which is at least partially accepted by the majority of classical military historians today, the first period is characterized by the abundant use of fairly light skirmishing troops, as well as more heavily armed infantrymen with large body shields and rapier \"antenna\" swords. Oddly enough, we find very few references to spears in early Mycenaean military contexts, particularly in the Linear B tablets, despite their prominence in Homer and among the classical Greeks. Now, according to the Linear B tablets, the most common piece of armor seems to have been the corslet, but what material these corslets were made of is unknown. They might have been leather, linen, bronze, whatever--and their shape is also unknown. \n\nDuring the late Mycenaean period we find abundant references to what appears to have been the beginning of the creation of a more heavy infantry, although it would have been buffoonish by hoplite standards. Hanson, whom I do not regard as being a good source, claims that these are not Mycenaeans at all, but Dorians, or at least Mycenaeans trying to imitate Dorian tactics to defeat them. Snodgrass believes that the repeated references to shields, corslets, helmets (by the way, that helmet is *not* cloth. It's made of leather and covered in bits of boar's tusk, like the famous Boar's Tusk Helmet in Homer from which it gets its name), and spears in the later Linear B tablets, from around the time of the fall of Mycenae, indicate a trend towards different equipment. Really the only representation we have of this period comes from the [Warrior Vase](_URL_1_), which depicts infantry carrying smaller shields, with spears, strange \"fore-and-aft\" helmets, and what appear to be bossed corslets. Unfortunately, although we are sure this dates from the later period we have no idea whether these are regular troops or not, although Snodgrass attempts to make connections between their equipment and the Linear B evidence. \n\nNow for the \"plate armor.\" The specific piece that is in the pictures you show us is called the [Dendra Panoply](_URL_0_), and the most famous piece is the Dendra Cuirass. Although fragments of bronze corslets have been found at other Mycenaean sites, as well as bronze scales, the Dendra Panoply is the only complete example of such a suit of armor from Mycenaean times, and is the only useful one, since the others don't give us much of an idea of what the stuff looked like. Snodgrass and others believe that the Dendra Cuirass dates from about the 15th Century, early in Mycenaean history. Snodgrass believes that this armor must have been used to some degree in battle, rather than being purely ceremonial, since even if it was a ceremonial piece it must have been modelled on something (also it's weight, expense, and extremely time-consuming upkeep probably points to a practical use). It is uncertain what exactly its use for, but Snodgrass makes an excellent case for its use as charioteer's armor, due to the extreme weight which would have been unwieldy for an infantryman and because the Linear B tablets frequently have links between the number of chariots and the number of thorakes (the symbol for breastplate clearly depicts a corslet of this type, although that does not mean that all breastplates were like this at all). Snodgrass argues for a two-handed lance without shield (which would have been difficult to carry in this armor, and unnecessary considering the arm-guards) atop a chariot driven by a charioteer.\n\nNow the Dendra Cuirass is very early, probably from around the 15th Century, B.C. This presents a major problem, for there are no representations of its use in contemporary art, and finds of bronze armor fragments become very rare later on. There are several theories for why this might be. One of the more popular is that as the Bronze Age drew to a close, accompanied by the political and economic breakdown that probably began sometime around the 13th Century, pieces of this type simply just became unaffordable and, due to their weight, were considered unnecessary and replaced with more affordable means of protection. Some scholars argue for a shift from an army of mobile skirmishers supported by an aristocratic chariot corps to an army of predominantly infantry, approaching heavy status--according to the theory this was due to shifting pressures as well as the growing political turmoil that marks the later period and possibly could be a result of the Beehive Tomb Period of much larger occupancies in graves. Neither of these theories have much direct evidence to support themselves. In fact, there are other theories that do not believe that the Dendra-type armor fell out of use at all. Kagan argues that heavy bronze panoplies of similar type, though probably more affordable, continued to be used into the Dark Age and up to the Argive Panoply, our first example of a complete hoplite panoply. This goes up against Snodgrass' observations that we find incomplete elements of hoplite panolies (helmets, greaves, and breastplates of the same type, just not together) all throughout the later Dark Age--though not before--and that this points to a gradual adoption of hoplite equipment. Almost everybody agrees with Snodgrass, who essentially proved Kagan wrong on this point. But, we still don't really understand what happened to these suits of armor, nor how they were used, or by whom.\n\nThe short version? We have no idea. And frankly, we aren't really sure what the heck the Dendra Cuirass is supposed to *be*, anyway."
]
}
|
[] |
[
"http://www.alternatehistory.com/discussion/attachment.php?attachmentid=1798&stc=1&d=1104896570",
"http://s2.hubimg.com/u/7878593_f260.jpg"
] |
[
[
"http://web.ics.purdue.edu/~rauhn/bronze_age_aegean.htm",
"http://www.varchive.org/schorr/warvase.htm"
]
] |
|
e4mzqf
|
What was Lee Harvey Oswald's motive for killing Kennedy?
|
I can't seem to find it anywhere, can anyone explain me?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/e4mzqf/what_was_lee_harvey_oswalds_motive_for_killing/
|
{
"a_id": [
"f9ehurd"
],
"score": [
44
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"text": [
"If we are going just straight off the Warren Commissions report, Oswald assassinated Kennedy for Cold War purposes. He considered himself a Marxist and was constantly trying to get to the Soviet Union. He also considered himself a support of the Cuban Revolution, being on the Fair Play Committee for Cuba. He even tried to get a visa to go to Cuba through the Cuban embassy in Mexico, but the Cuban's denied it, seeing him as being counterproductive. This context is important because the Kennedy president was known for high tensions with the Soviet Union and Cuba. There was the Bay of Pigs and the Cuban Missile Crisis. There was the Cuban Embargo as well as the sabotage campaigns that the American government launched against the Cuban government such as Operation Mongoose. \n\nThe tragic irony of this perspective if we take it at face value is that far from helping Cubans and the Soviets it made things worst. Castro in the lead up to the Kennedy assassination was actually negotiating with the Kennedy Administration to normalize relations. Both the Cuban and American ambassadors to the U.N at the time were working on a diplomatic solution and JFK was communicating with Castro indirectly through French reporter Jean Daniel on a way to normalize relations. It was actually in the middle of these negotiations that Castro heard the news of JFK's assassination and was of course as shocked as everyone else. \n\nNow the flip side to all this is that many have questioned the Warren Commission's report both because of the significant among of information that the FBI and CIA left out of their report to the commission, and also due to the fact that the House Committee on Assassinations in 1975 came to the opposite conclusion. They came to the conclusion that there was a second shooter and that the people behind the Kennedy assassination some how had some connection to the Cuban Exile community. So under this scenario assassinating JFK wasn't motivated by support of Fidel Castro but opposition to Fidel Castro, because of JFK's refusal to invade Cuba. Now the House Committee on Assassination's report itself has been questioned and debated as well."
]
}
|
[] |
[] |
[
[]
] |
|
7bdrah
|
where did the us's idea of becoming angels in the afterlife come from?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7bdrah/eli5where_did_the_uss_idea_of_becoming_angels_in/
|
{
"a_id": [
"dph55ci"
],
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],
"text": [
"_URL_0_\n\nApparently some theologian called Emanuel Swedenborg started it, and it has been a popular idea ever since.\n\nAnd this:\n\n > The Bible uses \"angel\" and \"man\" almost interchangeably when speaking about angels. If angels were a separate race, the Bible would not refer to them as men, or people. That would be like calling a horse a sheep, or a pig a donkey."
]
}
|
[] |
[] |
[
[
"https://christianity.stackexchange.com/questions/40032/what-is-the-biblical-basis-for-humans-becoming-angels-after-they-die"
]
] |
||
6rteyh
|
at what point in a presidency are changes in the economy attributable to the sitting president and not the former?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6rteyh/eli5_at_what_point_in_a_presidency_are_changes_in/
|
{
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"text": [
"That will always be open to interpretation. We're still feeling the effects of economic events that happened decades ago. History doesn't really sort itself into convenient boxes like that.",
"Pretty much never. Presidents have very little influence over the economy. It's Congress that has the power to create laws and direct government spending. The president just has to say \"yes, that proposed legislation will be a law,\" or \"no, I won't let that be a law\". And in the second case, Congress can override the president if a 2/3 majority wants to pass the law.",
"There's really no way to quantify. Also, the President has very little power over economic matters, it's really Congress that makes the difference, and even then it's hard to measure. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
f7cqhj
|
how did geese not get hunted into extinction?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/f7cqhj/eli5_how_did_geese_not_get_hunted_into_extinction/
|
{
"a_id": [
"fiaeyhd"
],
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2
],
"text": [
"If you start clubbing the geese they will become harder to get close to. Animals become acclimated to situations. If these geese were used to being hunted they would not be so relaxed around humans. Where I live you can not hunt deer near the airport. The deer there will basically walk right up to humans. Ten miles up the road where deer can be hunted they flee the instant they sense a human is near."
]
}
|
[] |
[] |
[
[]
] |
||
5aw8xy
|
Some of George H.W. Bush's fellow pilots were executed and eaten by their captors after being shot down over the Bonin Islands in WWII. How common was cannibalism in the Pacific Theater?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5aw8xy/some_of_george_hw_bushs_fellow_pilots_were/
|
{
"a_id": [
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"d9jxmki"
],
"score": [
128,
24
],
"text": [
"I had the unfortunate privilege of writing about this [here](_URL_0_).",
"James Bradley talks about this in Flyboys, how does that book rate for accuracy with you historians?"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/3ribf6/according_to_anthony_beevors_the_second_world_war/"
],
[]
] |
||
3qwznl
|
how much 'ping' does information take from human eyes to beeing processed in the brain
|
I hope my question is formulated correctly since english isnt my motherlanguage (..and i'm 5)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3qwznl/eli5_how_much_ping_does_information_take_from/
|
{
"a_id": [
"cwj1pay",
"cwj1qms"
],
"score": [
2,
6
],
"text": [
"\"ping\" is not a word I'm familiar with, at least not in this context. Do you mind explaining a little more?",
"\"It takes about 0.15 seconds from the moment light hits the retina to when the earliest recognition of basic object identity can occur.\"\n\nThis is a link to an in-depth explanation by Paul King, a computational neuroscientist:\n\n_URL_0_"
]
}
|
[] |
[] |
[
[],
[
"https://www.quora.com/How-fast-does-the-brain-compute-visual-information-From-light-reach-the-eye-to-awareness-of-impression-And-how-does-the-information-travel"
]
] |
|
5pb1gh
|
Can water be frozen in an airtight container?
|
The picture of the Coke pushing the lid up on the bottle on /r/all made me curious. If you put water in a container that left no space around the water and wouldn't break, could you freeze the water? If so (or if not), what would it do?
|
askscience
|
https://www.reddit.com/r/askscience/comments/5pb1gh/can_water_be_frozen_in_an_airtight_container/
|
{
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"text": [
"There are [17 known phases of ice](_URL_0_). When you deal with ice, you are almost always dealing with I_h which expands as it freezes. However, at different temperatures and pressures (pressure being the more important one here) different types of ice form. In the case of staying close(ish) to regular freezing temperature, and upping pressure until ice forms, you'd end up at [Ice III](_URL_1_). \n\nYou're unlikely to see this outside of a lab though, since you need to put water into a container which can withstand over 43,000 PSI of pressure, otherwise the ice wins and will crack the container. ",
"Follow-up question. \n\nA few days ago I wanted beer chilled quickly. I put the glass bottle into a plastic cup which I then filled with ice and water.\n\nI promptly forgot about the beer and opened the freezer yesterday. Beer and water were both frozen solid.\n\nThe plastic cup was broken, but the bottle did not crack, nor did the beer push out the top.\n\nWhy not? Did the pressure of the freezing water in the cup (which I assume froze first) push in and prevent breakage? If so, how did the pressure inside the bottle dissipate?",
"Slightly related question: when supercooling happens, what exactly is going on ice stage wise? Is it basically skipping Ice II stage and then when it is disturbed it goes from Ice III to Ice II?\n[Relevant gifs](_URL_0_) of \n[what I'm asking about](_URL_1_)",
"Can't find an answer. Hope someone here knows. Question: For the actual experiments, what container did scientists use to freeze water without cracking said container? And is there a photo?\n\nI can't picture how it is possible. All containers need an opening to add water and then the sealed opening becomes a weak point susceptible to cracking (like a bottle lid). No matter how thick the steel, there needs to be that opening to add the water. \n\nAlso, how do they actually view the ice? They can't take it out of the vacuum and view it under a microscope. It seems that it will instantly change once out of the vacuum. \n\nHow in the world can they make a totally sealed vacuum strong enough to withstand cracking but also include tools to view the water's molecular structure while in the vacuum? ",
"you probably meant to specify a rigid container but otherwise the average plastic water bottle is designed with ribs so that the volume can change a considerable amount and permit the water to expand and contract through a range of temperature, including frozen solid, without rupturing the container.",
"Sort of maybe not really related, but maybe you would find interesting. There is something called a triple point of water cell. It contains water in a glass tube essentially in a vacuum. When the cell is frozen to 0.1 C degrees all three states of water will exist simultaneously (solid, liquid, and gas). I personally have used used it many times at work which is where I have my information, but I'll leave a link to a Wikipedia article.\n\n[Triple Point of Water](_URL_0_) ",
"Can someone explain to me the energy transfer in this? \n\nSo by cooling the water you reduce the internal energy of the system...\n\nWhen the ice expands, work is done on the container by the ice, where work done = force x distance, clearly the distance it displaces the container top is small but the force must be extremely large and therefore the work done also large, relatively speaking.\n\nTo me it seems that by reducing the energy of the system you have also released a further large amount through mechanical work. \n\nIs this the latent heat energy being transferred to mechanical energy or what? Any ideas?",
"hope the graphic I linked below helps to explain this. Generally speaking if the water pressure within a container is high enough, even water that is an environment well below freezing (like an outdoor freezer in winter) won't freeze because the pressure prevents the water molecules from changing from liquid to solids. This phenomenon is called super-cooled-water-moleculces. There are ways in a lab to make water so cold that even the high water pressure won't prevent it from freezing. It is almost impossible to replicate on Earth in nature. \n\n_URL_0_",
"I once put a water bottle in the freezer. I took it out the next day, to my surprise it wasn't frozen solid at all. I started to drink it and then the water in my mouth and bottle froze instantly. There's some kind of weird science about pure water and not moving it that keeps water from freezing into ice until you move it after. \n\nFreaked me out though, that moment you're expecting a liquid and find a solid.",
"Kind of a side-point rather than a direct answer, but if the water is pure and the container is smooth, water will become supercooled and still be liquid far below freezing temp. As soon as an impurity is introduced (adding something porous or jostling it enough) it will begin to freeze very rapidly. It's actually fun to try this out with distilled water and a clean container, and sometimes it can happen by accident in everyday life if you live in a place that gets cold enough and the conditions are right.",
"I will put water in a plastic bottle and chill it in our freezer.\nAfter a few hours, I take the bottle out and shake it about. The water is liquid, but because of the shaking, it goes into this 'freeze' mode and I can watch it become a slushy solid in front of my eyes in a mater of a second or two. Why does the water react like this?",
"This question is a matter of heat transfer. In basic terms and in an ideal situation you have 3 forms of heat transfer occuring; the convection transfer of heat from the outside air onto your airtight vessel, the conduction of heat through your vessel, and the convection transfer of heat from the vessel to water where the fluid is touching the walls of the vessel. (**note there would be transfer of heat from the vessel to the air inside the container and then to the fluid which would run in parallel to the convection of the vessel on the water and speed up the process. Just because the vessel is airtight from outside air does not mean there would not be air inside the vessel. This vessel is isolated from outside air not a vacuum. You could not make this problem work in a vacuum because as you made the vessel more and more like a vacuum, you would lose the liquid water to gas as the pressure dropped. Continuing to do this would result in a perfect vacuum meaning no molecules are present meaning no more water in the system). The transfer of heat due to convection is written as q=h*As*(Tsurface-Tsurrounding) where h is a heat transfer coefficient (constant for the surface), As is surface area, and the Ts are the temperatures of the given. This equation is dependent on the starting temperatures of the air outside and the surface temperature on the vessel along with the vessel surface area and the air has a transfer coefficient on how quickly/effectively it transfers air. The second step is to look at the conduction of heat through the vessel which is written as q=-k*dt/dx where dt/dx is the change in temperature with respect to the change in area and k is a coefficient constant of the material. More often the equation is rewritten in mesurable terms as q=-k*As (T2-T1)/L where As is the surface area, L is the thickness, and T2 and T1 are the temperatures on the inside and outside of the vessel. These are your dependents in this equation. Then we would set up another convection of the heat transfer from the vessel to the water. So to answer your question, yes it can be frozen in an air tight container barring you don't use a super insulating material to contain it. If you use a pop bottle for example the cool air could transfer through the plastic and into the fluid therefore freezing the fluid. If you had the cap off the cool air could transfer directly into the fluid without having to go through the bottle. This would sped up the process. The whole process is pretty much dependent on the type of vessel you would use to contain the liquid and who resistant it is to heat transfer. (Note this whole response is written by looking at heat transfer as the cold air moving to freeze the water so it made sense for the question. When actually calculating these numbers you would need to look at the heat transfer from the water to the air or make all your q answers negative)"
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Ice#Phases",
"https://en.wikipedia.org/wiki/Ice_III"
],
[],
[
"https://media.giphy.com/media/uK5GHXadQImTm/giphy.gif",
"http://i.giphy.com/REbnpNWr6GgBq.gif"
],
[],
[],
[
"https://en.m.wikipedia.org/wiki/Triple_point"
],
[],
[
"http://d32ogoqmya1dw8.cloudfront.net/images/research_education/equilibria/h2o_phase_diagram_-_color.v2.jpg"
],
[],
[],
[],
[]
] |
|
2s4265
|
a basement sump pump
|
ELI5: A Basement Sump Pump
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2s4265/eli5_a_basement_sump_pump/
|
{
"a_id": [
"cnm11zf"
],
"score": [
3
],
"text": [
"Submersible pumps are used to push liquids from one location to another. The basement type gets water from somewhere you don't want it (your basement) to somewhere else (your yard or other location) "
]
}
|
[] |
[] |
[
[]
] |
|
22gns6
|
Are there records of any other kamikaze-type pilots in history?
|
Like the title says, I'm curious if the Japanese were the only pilots ever to implement this strange technique. I'm referring to fighter pilots only, not other suicide type missions.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/22gns6/are_there_records_of_any_other_kamikazetype/
|
{
"a_id": [
"cgmmvzp"
],
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"text": [
"There was the Sonderkommando Elbe, which utilized stripped-down fighters to ram Allied bombers in April of 1945. The idea was that trading a single fighter with one pilot for a fully-crewed bomber was a net win for the Germans. When used to ram the tail surfaces, cockpit, or engines the damage could be quite severe. Also, since he was over friendly territory the German pilot may be able to bail out and repeat the tactic in the future.\n\nAs promising as this tactic sounds, there were several flaws. First, it was implemented so late in the war that there were sufficient Allied escort fighters to ensure that the damage was not significant enough to discourage future raids. Secondly, new German pilots at this point of the war had little in the way of training so their skills were not at the same level of earlier German pilots (or those of their Allied opponents). Lastly, by its nature the Sonderkommando Elbe was a small experimental force. Their single raid did bring down some bombers, but not nearly enough to stem the tide of the Allies. Even had they had a 100% success rate, it would have been a small victory too late in the war to significantly influence future events.\n\n[I found a video of the History Channel's Dogfights that dramatizes the raid in question.](_URL_0_)\n\nThere were also isolated incidents of single planes attempting to ram other planes or enemy targets in both world wars."
]
}
|
[] |
[] |
[
[
"http://www.youtube.com/watch?v=JmDYdfb02tc"
]
] |
|
e3ckmh
|
what are djs listening for when they bring headphones to their ear?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/e3ckmh/eli5_what_are_djs_listening_for_when_they_bring/
|
{
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"text": [
"basically: the next track\n\nif it's synced, same tempo, if the drops line up and sometimes what it sounds like bc they cant remember 5000 tracks\n\nedit: especially when it's a dj with turntables the tempo part is very necessary\n\nelse the crossfade sounds like crap",
"They have two turntables/tracks each with different songs. One of the songs is being played live to the club while the other track is played on the headphone so the DJ can beat match them (same tempo/bpm) and make a smooth transition or mix before playing it to the crowd.\n\nHowever there are also a lot of fake djs that just play a preset playlist. They will often do the headphone thing just as an act to sell it to the crowd, kinda like a singer lip syncing.",
"Thank you! Maybe a silly follow up question but don’t most big DJs have a planned set of songs they wanna play? Wouldn’t they already know the line up and bpm and things?",
"They are \"beat-matching\". \nTake House music for example. Depending on subgenre, most House music is between 120 and 130 beats per minute. You'll have one track playing at, say, 125 bpm. You want to mix in the next track, which is, say, 128bpm. You need to match them. \nTo start you have the crossfader all the way to the left (platter 1), which means only the track on the left platter is playing through the speakers. You start the next track on the right platter (2) in time with 1, listening in your headphones to hear if it's playing too fast or too slow. \nYou adjust the Pitch (the speed of the record-- most turntables have a pitch fader for + or - %15 speed). So you bring the pitch down on platter 2, so the incoming track is also 125bpm. If you know your music well, you'll already know if it needs to be pitched up or down. \nNow you go back to the first beat on track 2, and 'drop' it in again. Keep in mind, House music progresses by 8-16-32 beats (the \"phrase\"). So you're looking for the 'right' beat, so that track 2, for example, has a building bassline, as track 1 is dropping out a bassline, drums, vocals, and so on. This is called \"phrase-matching\". \n Good DJs can do this on the fly, simply because they know their music from start to finish. You also have bass, mid, and treble controls to adjust the tracks. \nIf you do this correctly, you are stitching together 2 tracks in realtime, creating a blend of both tracks, one flowing into the other. \nThe best DJs have their own 'flow,' that keeps people dancing, building/releasing energy or teasing the next theme that you want to blend in. It's a pretty straightforward idea but it provides endless possibilities for creativity."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
4br8ve
|
Was there any public outrage at the Nazi Party flag becoming the official state flag of Germany?
|
Or was resistance effectively futile by then?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4br8ve/was_there_any_public_outrage_at_the_nazi_party/
|
{
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"text": [
"When the Nazis took over in 1933, the Nazi Party flag did not become the German national flag right away. On March 12, 1933 president Hindenburg decreed that Germany should henceforth have two flags: The Swastika Flag but also the old monarchic [Black-White-Red flag](_URL_1_) used before the Weimar Republic.\n\nThis was a popular move especially among the political right who had rejected the Black-Red-Gold flag of the Weimar Republic as a symbol of the »November criminals«, i.e. the Social Democrats founding the Republic in November 1918.\n\nThis double-flag business lasted until 1935 when at the Nuremberg Party Rally of that year, also famous for the introduction of the Nuremberg Racial Laws, the Swastika Flag was made the sole flag of Germany. \n\nTwo reasons precipitated that move: Earlier in 1935 in the course of an anti-Nazi protest in New York some dock workers had ripped down the Nazi flag from a German ship, the Bremen. When tried they were not sentenced because as the argument went, the Swastika Flag was not the official state flag of Germany.\n\nAdditionally, by 1935, the Nazis had managed to get rid of the internal conservative opposition. With Hindenburg dead and most of the initial conservative ministers out of the government and some of them even jailed, they felt it was time to complete their grip on power also symbolically by declaring their flag the sole flag of Germany.\n\nFrom what I am familiar with, this did not lead to huge protests or outrage, mainly because so many people were already used to the Swastiak Flag being the almost exclusive flag of Nazi Germany, even from the time there were two. The only thing specifically mentioned is that some Catholic priests refused to hoist the Swastika flag on high holidays and instead used the Black-White-Red one. But these instances, mostly mentioned in the SD Reports, were rare and limited to people the regime knew were a problem.\n\nEdit: Found another instance: The Sopade reports of the exiled Social Democratic Party leadership mention that in 1936 some workers in the Ruhr area tore down several Swastika flags and waved a Black-Red-Gold flag to show their opposition. Several of them were arrested and one allegedly send to Dachau.\n\nSources:\n\n* Meldungen aus dem Reich 1938 – 1945. Die geheimen Lageberichte des Sicherheitsdienstes der SS, hrsg. von Heinz Boberach, Bd. 1 – 17, Herrsching 1984.\n\n* [Reichsflaggengesetz 1935](_URL_0_)"
]
}
|
[] |
[] |
[
[
"http://www.documentarchiv.de/ns/1935/flaggen1935_ges.html",
"https://de.wikipedia.org/wiki/Datei:Flag_of_German_Reich_%281933%E2%80%931935%29.svg"
]
] |
|
hpaf3
|
Is there a physiological explanation why some people can easily display some types of fine muscle control (raise one eyebrow, wiggle nose, bounce pectorals ...) and others can't.
|
Just wondering if the ability, or at least the ability to easily do some of these things, is a function of our nerves and muscles, or if the whole thing is just in our heads.
|
askscience
|
http://www.reddit.com/r/askscience/comments/hpaf3/is_there_a_physiological_explanation_why_some/
|
{
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"I taught myself to move each eyebrow independent from each other. Same thing with nose flares. Its more practice than anything.\n\ni believe it is more concentration, isolation of the muscle and practice.",
"The first 6 or so weeks of working out, it is mainly neural development, training your brain to better use your muscles before they start to get big.\nThis suggests some people nay be more finely tuned to their muscle use and so can bounce them. This and just learning what movements are by which muscle.",
"Related: Perhaps this is a trivial question. I don't know. But I'm curious.\n\nWhen the microtears occur in the muscle fibers, how do they 'know' (poor choice of word, certainly) to rebuild stronger & more resilient than before? Is there just a mechanism that invariably causes this to occur when injured, or is it just the way our biology is? There has to be more elucidation in the answer than the latter suggestion..."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
588sst
|
Where did the custom of giving a "key to the city" originate?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/588sst/where_did_the_custom_of_giving_a_key_to_the_city/
|
{
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"text": [
"Tag along: What exactly did the \"key to the city\" actually open? City gates? The doors in the castle?"
]
}
|
[] |
[] |
[
[]
] |
||
2v7uve
|
Can someone with a compromised immune system still have an allergic reaction?
|
Allergic reactions are, to my knowledge at least, an exaggerated immune response to a harmless compound. But if someone's immune system was compromised by AIDS or high radiation dosages or even immunosuppressants, would they still be able to mount a response?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2v7uve/can_someone_with_a_compromised_immune_system/
|
{
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"text": [
"I think this is an interesting question!\nSo, I think it depends on what cells we are talking about and thus what was the cause of the compromised immune system.\n\nLet's just start with AIDS and thus infection with HIV. HIV infects the T-cells, or more precisely a population of T-cells that is also called T helper cell. Over the course of AIDS the count of these cells is reduced massively. (_URL_0_)\n\nInterestingly the same cells are implicated in allergies in the way that the TH2 (T helper cell 2, there are different subpopulations of these cells) responses of the immune system can benefit development of allergies. (_URL_2_)\n\nSo I guess you could conclude that developing new allergies should be reduced in patients suffering from AIDS. I haven't really found any info with a quick search on how it is with developing new allergies when under the influence of AIDS, only found a semi-informative link with no real sources (so beware of taking this for real!) here: _URL_1_\n\nBut, although these TH2 cells may have a part in developing new allergies, the actual cells getting activated in an allergic response are mast cells. (more info about them here: _URL_4_)\n\nThey are not getting infected by HIV and to respond to allergens they only need special antibodies produced by other immune cells, called B-cells. So, in theory, if a patient already had an allergy, they should still have allergic responses while suffering from AIDS, since mast cells are not affected directly by the virus. Another quick look brought up this study here: _URL_3_\n\nI admit I did not read the whole article, but the abstract already states what I said, these T-cells getting depleted in the course of AIDS are not necessary for these patients to develop an allergic response.\n\nTo tackle all other scenarios (like radiation, immunosuppressants and so on) you would need to know what cells are targeted. If all of them are affected you maybe get weaker responses to allergens overall, if specific cells are targeted and they are not mast cells, you will still get allergic responses to allergens you already encountered.\n\nHope that answered your question and I didn't mix up things."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/T_helper_cell",
"http://allergies.about.com/od/allergies101/a/Hiv-And-Allergies.htm",
"http://en.wikipedia.org/wiki/Allergy#Cause",
"http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0097893",
"http://en.wikipedia.org/wiki/Mast_cell"
]
] |
|
cu3job
|
what exactly is epistemological solipsism? or just epistemology and solipsism for that matter?
|
I saw the term recently and tried to look it up, but every article/definition I found seemed to assume every person reading it has a degree in psychology or something. Please spare me the fancy technical terms and just explain it simply like I know absolutely nothing about philosophy, idealism, or psychology (because I don't). Similes or examples would also be very appreciated, if possible.
*\*Note: Not sure why, but there wasn't an option to list this post under a "Psychology" flair/tag even though there clearly seems to be one, as other posts are marked with it on this subreddit. That's why it's tagged "Other" instead.*
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/cu3job/eli5_what_exactly_is_epistemological_solipsism_or/
|
{
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"exr0xs3"
],
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21
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"text": [
"Epistemology is the branch of philosophy that deals with the nature of knowledge and similar concepts: what does it mean to know something? How can we know stuff?\n\nSolipsism is usually taken as the skeptic belief that the only thing existing in the world is you or your mind, or rather, being unsure that anything exists outside of it.\n\nEpistemological solipsism (damn that’s a mouthful) can be thought of like this: you know what’s going on in your mind. You have thought and feeling and all those neat stuff originate in your mind itself. But every thing you know about the world - how it looks or sounds, the existence of other people - all that comes from outside your mind and through your senses. The solipsist argues that you can know that these things exist as you perceive them or at all.\n\nDescartes asked this very question in a way that makes sense: you put your spoon in your cup of water and it looks like it’s snapped in half. You’re smart though, and you say “I know my eyes are tricking me, and the spoon is intact”. Well, if your eyes tricked you then, how do you know they don’t always trick you? How can you ever be sure of anything your senses perceive?\n\nMany philosophers tried to tackle this question, from Descartes, Locke, Kant and more. All of their solution rely on something you take for certain - the existence of outside objects, your sensory input, or even god."
]
}
|
[] |
[] |
[
[]
] |
|
1souo0
|
Why are the Jovian planets (gas giants) so much more spread apart from each other than the Terrestrial planets?
|
The solar system is like this, with o's being Terrestrial planets and a's being Jovian planets:
SUN o o o o a a a a
Why?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1souo0/why_are_the_jovian_planets_gas_giants_so_much/
|
{
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"text": [
"Mars and Earth have orbits about half an AU apart. If you replaced Mars and Earth with gas giants, their mass would be such that whenever they passed near each other, they would have a pretty strong gravitational deflection. Eventually, they would drift farther apart to a distance where their gravitational interaction was moderate enough that their orbits weren't constantly disrupted. The more massive planets are, the farther apart they have to be in order to not completely disrupt each others' orbits.",
"One of the things about this question is that we don't completely know. When we look at a list of exoplanets, we see that is a wealth of gas giants and super earths in other solar systems, [but they many of them orbit their sun very, very closely.](_URL_0_).\n\nA system similar to ours - with gas giants outside and the planets closer- [has been discovered very recently.](_URL_2_) However, this system is much different than ours: it can be entirely contained within 1 AU.\n\nAs far as our system goes, ~~I believe the leading~~ theory is that the existence of Saturn prevented Jupiter from marching inwards [like many other planets.](_URL_1_).\n"
]
}
|
[] |
[] |
[
[],
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"http://stardate.org/astro-guide/btss/planets",
"http://adsabs.harvard.edu/abs/2005DPS....37.2507M",
"http://www.universetoday.com/106759/"
]
] |
|
3c1wzc
|
How do historians view Tom Holland's "In The Shadow of the Sword"?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3c1wzc/how_do_historians_view_tom_hollands_in_the_shadow/
|
{
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"csryokx"
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"text": [
"/u/shlin28 has a few views on this\n\n_URL_1_\n\n_URL_2_\n\nthe historical doubt article seems especially good with comments by others like /u/yodatsracist . \n\nAnd Tom Holland himself briefly talks about his reception to his work in his history of byzantium podcast interview here _URL_0_\n\n"
]
}
|
[] |
[] |
[
[
"http://thehistoryofbyzantium.com/2014/11/06/episode-57-why-did-the-arabs-win-part-2-in-the-shadow-of-the-sword/",
"https://www.reddit.com/r/AskHistorians/comments/1c4p2p/is_there_historical_doubt_of_the_historical/",
"https://www.reddit.com/r/AskHistorians/comments/29rerl/flaws_in_the_book_beyond_the_sword_by_tom_holland/"
]
] |
||
49dpmo
|
why do college professors curve test grades? wouldn't that just encourage laziness and be an example of the failure of the instructor's efforts to ensure students learn?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/49dpmo/eli5_why_do_college_professors_curve_test_grades/
|
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"text": [
"I had a professor say once, \"If you ace my test, I haven't tested you at all.\"\n\nThe goal of the test is to determine what the student have learned. By making the test difficult, you are able to determine both the upper end and lower end of the abilities in your class. This is a good thing, as you are able to understand what people know _and_ don't know.\n\nNow, that said, it wouldn't be fair to the students to make a test so hard that no one could pass your class - that wasn't the goal after all. So the grades are done on a curve so as to reward the students who have learned the most with the grades they deserve.",
"A traditional curve actually lowers the grades of the lower scoring students proportionally to how the top students are boosted. Done to create a bell curve and reward the top students while sifting out the lower scoring ones.",
"All college professors I had and know (I'm now an adjunct) don't curve a la a Bell Curve, but instead they scale the grades up. They find the class average, set that to a B or B-, and scale higher grades up to As and lower grades to Cs and Ds. \n\nSo if the class average is 65%, scale each grade up by 50% of the missing points. \n\n65% - > 82.5%\n\n50% - > 75%\n\n20% - > 60%\n\n95% - > 97.5%\n\nIt keeps your students from failing (unless they really deserve to).",
"It could encourage laziness, as long as every single student agreed to not try hard and let the curve carry them to a C. If 1 single student tries, then they will get a high grade and kill the curve.\n\nPutting real numbers to it. Let's say we have 10 students, and a 4 choice multiple choice test (A,B,C,D type). \n\nThe students get together, and agree to not study and just answer randomly and get a 25%. The professor says that the average of the class should be a 75%, so if the average of the class is lower he will curve it up to 75%.\n\nThe students take the test, all get 25% answering randomly. The test gets curved up to 75% and everyone is happy (C's get Degrees!).\n\nThen one day, a student realizes that they can study, get a better grade than a 25% and get higher than 75% when it curves. So let's stay 1 student does this and 9 answer randomly. That 1 student gets a 50% and the other 9 get 25%.\n\nNow the class average is a 27.5%. The professor curves the scores up by 75-27.5 or 47.5%. If you got a 25%, your new score is 72.5%, but if you were the 1 student who tried you now have a 97.5%. C's get Degrees, but A's make more money.\n\nNow the other 9 students are thinking, I just need to study a little so I don't get left behind, and the scheme breaks down as more students study and actually try.\n\nSo basically, if every student is in on it, a curve can make it so nobody tries and everyone gets a C. The moment any student tries to get above that, they inflate their own score and decrease the score of their peers, and the scheme to get free C's breaks down.\n\nSomeone will always try on the test, so while the curve can be nice if a test is too hard, it is difficult for all the students to band together and break the system.",
"Using a curve allows for test results that reflect the ability and effort of the students while compensating for the quality for the teaching and reading. If a teacher does not adequately explain a topic, something disrupts the learning of that topic, or the textbook contains an error students are not penalized for not answering that question correctly. If even the hardest working and brightest students miss a question, it might be an indicator that the students are not at fault.\n\nSimilarly, test writers don't need to design their tests such that average students receive average grades, and exceptional students receive exceptional grades. They can include questions that are excessively difficult without essentially lowering the maximum grade. \n\nDoes it encourage laziness? Possibly, but there are factors and methods that can decrease the risk.\n\nStudents could theoretically conspire to not make an effort on a test, so that the average score is very low but still raised to a decent score due to the curve. This only works if every student cooperates, if a few do well on the test they can \"throw off\" the curve, and doom their classmates. As enumerated by another commenter there is a strong incentive to betray the conspiracy, as those who do see greater gains for a small amount of effort compared to when everyone makes an effort. Graders can discourage this further by including averages from other classes or sessions when calculating the curve, or simply deciding on a maximum benefit of the curve.\n\nInstructors could theoretically slack off as with a curve most of their students will get average grades regardless of the quality of their instruction. In many cases different instructors teaching the same course will have a common final exam. Even if this exam is on a curve if one instructors classes consistently have a lower raw score this would indicate to administration a problem with this instructor. With a smaller pool (instructors instead of students) it does become easier for collusion to survive. Another instructor for an upper level class may also find that students coming from a prerequisite taught by a specific instructor are consistently unprepared, and thus expose their laziness. This is probably not very common, as no one wants to be a snitch or get a colleague fired. Word of mouth and _URL_0_ are probably the most effective deterrents, as a instructor who is consistently unable to fill their classes may risk their job. Then again easy teachers attract lazy students.",
"Because administration will pressure them not to fail students, who pay tuition, who pay professors' and administrators' salaries, etc....\n",
"English is not my first language, so: what does curving a test mean? Is that an American thing?",
"College prof here. First, I NEVER curve my tests. I have a set amount that I want my class to know and they either succeed or fail. After having taught for so many years, I think my spidey sense is pretty good for setting my expectations. \n\nHowever, I have well-respected colleagues that regularly curve tests and do it to force a natural distribution of grades (certain percentage are an A, certain percentage are a B etc). Their point is that students have a natural distribution of understanding and so the grades should reflect that. Giving them all an F would seem to indicate that all the students are idiots, which is improbable. A curve is just designed to acknowledge that distribution.",
"I am a college professor and I don't like curving grades. But on the same token there is a normal \"distribution\" meaning typically so many A's, B's, and C's and I don't want to hurt the grades of my students if the test was harder than expected. So if for some reason a test turned out to be much harder rather than \"curving\" what I like to do is give the students the opportunity to increase their exam score by writing a couple sentences for any question they got wrong explaining why the answer was what it was and I will give partial credit. That way the student's who really care actually learn something in the process (and then improve their exam score) while those that \"don't care\" and do not research and explain the question and correct answer do not. BTW, I teach college Economics.\n\nHowever, I have in the past \"slightly curved\" a final exam that turned out harder than expected but only because we will not see each other again to give the students the ability to explain any question and answer on THAT exam.",
"Because it is incredibly hard to calibrate exams to be of equal difficulty over the course of years. It's an easier assumption to assume that large classes of students are about of equal average ability from year to year, so grading on a curve makes sense. If the average test score for this year's 300 students is 65%, and last year's average was 72%, it is way more likely that the test was a little harder, not that the class is all 7 points dumber. \n\nUsing a curve is a smaller class (10-30 people) is more problematic from the assumptions point of view.",
"I haven't see something I experienced as a TA while in graduate school hasn't been mentioned so I'll add it, thought it doesn't apply 100% to the question at hand. In the physics department we normally had a professor lecture several times a week and then undergraduates spent an hour or two in class with their TA (most often a physics grad student) who often handed out homework assignments and graded them as well as any lab experiments and write-ups. Some TAs were great teachers and some were shitty teachers, your skills didn't matter too much since everybody pretty much had to take a turn teaching at some point during their time as a grad student. Curving the grade was one way to keep someone from being penalized for having the bad luck to have a shitty teacher. We were instructed (required) to have our final grades for our sections (we usually had 2 or 3 individual classes a semester) follow a standard Gaussian distribution. \n\nThis did a lot to equalize things for the students who were pretty average, the ones whose grades really varied based on the teaching ability of their instructors but for the most part those who really understood things had high enough scores on the mid-term and final exams the professors gave out that they could swing an A or a B+ based on their performance on those multiple choice tests. The real downside and what was horribly shitty for me as a teacher was I had to give some students who clearly would have been the brightest in some other sections (with bad teachers, for example) Bs instead of the A I thought they deserved because they weren't the cream of the crop in my group of 30-45 students. It was a shame and I would often take effort and the product of personal conversations into account but some people (I'm looking at the pre-med students here) were completely obnoxious about how they deserved an A and they wouldn't get into med school if I gave them a B.\n\nFor me personally, it meant very few people got As because I didn't think many of my students deserved Ds or Fs. There were always enough students who stopped coming to class or just did nothing at all so I could give them Fs and give the one or two really bright kids As but mostly people got grades in the low B (B, B-) range. \n\nTL;DR - sometimes grades are given on a curve to even out the effect of having good teachers and shitty teachers covering the same material.",
"I went to one of the best engineering schools in the country. If there weren't a curve, nobody would graduate. The tests aren't about validating what you know. It's about identifying what you don't know. If the majority of students fail a specific subject area on the test, professors know to focus on that in future lectures. In this fashion the quality of education actually improves and there's no need to ding students for an unnecessarily difficult question - especially when the test is on a subject like thermodynamics where acceptable methods can yield different answers based on how many factors you take into consideration. ",
"each test is unique and individual and therefore, statistically it is almost impossible to determine a level of ability by simply setting a test. Yes, I know this sounds counterintuitive.\n\nWhat tends *not* to vary so much is the *average* level of attainment of a large cohort of pupils who have received similar input (tuition). This will typically form a normal distribution curve.\n\nTherefore, when setting a threshold, you take one large cohort of students and give them all the same test. Overlay the scores against a normal distribution curve and this will tell you where the 'pass' mark should be. on one test this may be 40%, on another it could be 60%. Standard deviations are used to determine grades within the curve.\n\nThis system provides fairly accurate benchmarks. To get the most accurate and 'fair' results for an individual you need to repeat this exercise with the same cohort and different tests multiple times. We tend not to do this as it adds too much stress to the student and detracts from teaching time (nobody learns anything by sitting a test).\n\n\n*source: school principal\nEdit - typos",
"I took a class where the class average was 21/100. The top student got a 47. When a good percentage are comfortably making A's it indicates a lack of rigor in the class. It is also highly useful in professional training where you want to identify the superstars in order to give them better opportunities - these students might get lost in the crowd of high achievers if you weren't trying to winnow out the best.\n\nEdit: The purpose of the curve is to let the competent but not magnificent students through while still identifying the magnificent, useful especially in classes with hundreds of students.",
"The high school mind set \"their goal is to make me learn\" doesn't apply. Curving grades is NOT supposed to make you learn, it's supposed to give you a way of comparing yourself to others and thus elucidate what you should revise, assuming you WANT to do so. How it works was in depth explained by other redditors.",
"Realistically, it's not possible for average test takers to master EVERYTHING. This is why most standardized tests are raw scores (actual % of correct marks) that are converted by some process into a score grade, or...your score is converted into a percentile/quartile ranking which compares your score vs everyone else who also took the exam at the same time. ",
"College student here. I'd say its best we leave questions like these unanswered. I'm just happy to pass. A curve you say? No complaints from me. ",
"The theory I've heard on this is that if everyone does poorly on the test, the test was poorly made.",
"I'm not a teacher or anything but once my high school teacher told me that he gave a curve because it was a way of making sure he was doing his job. \nIf some kids failed, it was because the teacher failed to hold their attention, make the material interesting, reach out to the students, etc. So the curve was compensation. \nHe said the by the end of the year, if the curve average had gone down, that means he had made progress and the progress was evident in the students' curve, which he recorded. ",
"Having a curve in a class or on a test is way to truly test students on their knowledge. If a student gets 100% on a test you may not have challenge them enough or tested them fully on their knowledge of a subject.",
"I think it's a terrible practice, and one that I never followed when teaching university and graduate courses.\n\nMany of my colleagues would construct tests that were very difficult, and required a very high level of intelligence to be able to figure out the correct answer to the hardest problems during the limited time of the test. I felt this was very bad practice - after all, the most complex problems we face in real-life virtually never depend on getting the answer correct in a single hour. \n\nInstead, I defined upfront **very clearly** what the students were expected to know. I taught the material that enabled the students to understand what I expected them to know, and this is exactly what I tested. I would be fine with giving every single student an A - indicating that each student mastered exactly what was expected of them. Note: This never actually happened. \n\nWhen I wanted to test more creative thinking, I'd do so by assigning a project for the course and/or a take-home test that the students would complete over a period of several days/weeks. This, of course, would require independent research, argument formation, and, frequently, data gathering and interpretation. This is how the real world works in science and business.",
"You need to remember that the exams are written by instructors each semester, and instructors are human. They may think their students really grasped a particular concept but the exam is the only real test, and at most schools there are several instructors of the same class and they all teach differently. The average for my calc 3 exam 1 this semester was 55. They wrote too difficult an exam. \nNow, this could be intentional and that's fine, so students see what they were expected to know and what they should really review to move on to higher level courses. However, if the average is below passing on every exam, nobody passes! So of course they will need to curve the grades to account for the exams being too difficult, which when done right will produce a much more even spread . Those who really weren't prepared for an exam of any difficulty will still fail, and those who had a reasonable understanding of the material will get the grade they deserve for knowing an acceptable percentage of what they actually need to know to pass the course.",
"It actually makes students study harder. Not only do they have to do well, they have to do better than the other students",
"In addition to other comments here, curving the grade can help eliminate \"bad\" questions on tests. Let's face it, sometimes we word things weirdly. What we're trying to ask may not come across to a student. One way to combat this is to grade each test, marking down which questions were right and wrong on a tally to see how the class did overall on each question, and tossing questions that a majority of the class got wrong as either \"bad\" or \"untaught\". Curving, while it doesn't have quite the same effect, can help adjust for those low-performance questions quickly, without the extra paperwork involved.",
"If you make a test where 100% is achievable then it's possible that two or more people will score the same 100%, but who's better? If you make the tests super hard and then curve it's more likely to show separation. ",
"Long Answer: \n\nIt's because the variance of knowledge is much higher for certain fields, and it's frequently difficult to assess skills properly because of that. Tests shouldn't be if you can get all of the answers right (some people are bad test takers, might have mis-read a question). It's about gauging total understanding in a field, and being evaluated on that basis. It also permits for evaluating a group of students if knowledge is skewed. If you have half the class getting 100% and several failing, then it's arguable that your test was too easy, since some of the kids fail no matter what. If you had a mean around a 60% with a few kids getting in the 90s, then you'd be better able to clarify how much the students learned, and then still give A's to however many you'd want. But even in a class of bright students, I'd rather have a mean of a 50 on an exam and give half my students A's then have half my students get 100% and then get A's. Unless you're amazingly smart you won't learn all the material, you will get a few questions wrong. That's the idea. You're meant to be challenged. But even with super difficult tests, it can still be challenging since sometimes you can have a situation where half of the class would get in the 90s or 100 no matter how difficult, and then it becomes a problem with bimodal distributions. \n\nShort Answer:\n\nAsians.",
"To me there are two folds to this. Is the goal of the test to differentiate students or to validate whether or not the students are competent in what they were taught. \n\nThe prior requires a good degree of separation, in the shape of a bell curve, appropriately challenging students will draw out this bell curve, differentiating the best from the average from the worst. This risk of this is that the exam is too challenging, and students are penalized by receiving an undeservingly low grade. Curving the exam allows instructors to challenge the students without the risk of jeopardizing their grades. Best example of a differentiation test: SATS, Weed out courses in college, HKCEE, HKAL, where there is a quota for acceptance at the next level, differentiation must be applied, ability to curve the test scores allows the instructor to challenge students, and differentiate.\n\nHowever, absolute scoring is a better system when the goal of the test is to validate the competence of the students in achieving the educational goal set out by the instructor. An example would be an intro history course for non history majors. There is no need for differentiation between students, as long as all the students meet the bar set out by the instructor, they all deserve an A. \n\nIn short, the test is to show what each student deserves. The ranking in the class (if appropriate or needed) and the grade the student deserves. Ability to curve the test allows both to be achieved if needed. ",
"Or have my teacher that just gives insanely hard tests and doesn't curve. Class average is a 52%?\n\n\"You all did great!\" \n\n75% of the class fails.",
"I don't think a lot of students really know the true definition or the mathematics involved in a normally distribution of grades, aka curve. A lot students say 'curve', but are really inquiring whether they will receive a horizontal shift, aka free points. \n",
"In my fluid mechanics class once we all bombed the exam except for one guy who sat in the front row. He got a 100% so the professor said he would not grade on a curve. He wouldn't treat it as an outlier.\n\nYears later that perfect student shot his wife in the head.\n\nTrue story bro. ",
"Our professor (Biochemistry) curved our test because it was the first time he had administered this exam. None of the class was able to finish the exam, and it enabled him to gauge how we have learned and how he should plan future exams.",
"I had a Physics class one time where the professor spoke so low no one could hear or understand her. Rumor was she had a stroke a few year back. Anyhow, the exams were so old they vaguely matched what she was teaching. I was getting like 60's and 70's, but got an A in the class.",
"My father was a math professor. I asked him once if he curved tests, and he said, \"No.\"\n\n\nI asked, \"But what if everyone fails a test?\n\n\n\"Then I write 25 F's down in my grade book. The math isn't any harder now than when I learned it.\"\n\nHe went on to say that if he did curve, he would take the square root of each grade and multiply it by 10, though.",
"Can I ask you a different question than everyone else? Why do you think 90-100% means \"A\"? I had a high school class where 80-90% was A, and the teacher saw himself as a failure if anyone got over 90, because that was the system at his British system. If 50% of kids get 95%+, then the teacher doesn't learn what kids do and do not learn. Our grading system is already arbitrary, but the curve makes it FAR LESS arbitrary.",
"As a former engineer student, my biggest problem with curving is that it discourage working together among students. Since if you help someone getting higher score than you in assignment/test, you could be shooting yourself since the curve will put you in a lower grade.\n\nThat is of course an absolutely fucking terrible attitude for any engineer student to have. Unfortunately I know this sentiment start to come in for a lot of students.",
"My understanding is that it's to assess whether or not the professor's teaching is effective or not. For example, if the majority of the students were to get around a 70% on a test, that reflects on the teacher meaning they were ineffective in teaching the material. This way, the students get a fair and appropriate grade that is reflective on the efficiency of the professor's teaching.",
"I teach architectural design at the graduate level. A big part of the reason I grade on a curve is, like many people here have said, it ensures that the problem assigned or the way I am teaching don't negatively affect all the students in my course. The other reason is that what we are doing is very difficult by design. I don't expect anyone to ace the course, if they aren't struggling I dial it up. The point being to teach you the things you need to survive out in the real world where there are no do overs or extra credit and where your work is probably going to outlive you and will impact the daily lives of thousands of people for better or worse. After you land your first job the only thing I've done for you that matters is teach you to always improve, rise to a challenge, not run, and have pride in the substance of your work. Grades are frankly meaningless, that's why professors grade on a curve. ",
"As someone who has written tests for a college-level course, it is *very* hard to write a test at the perfect difficulty so that there is a good distribution of those in the 90-100 range, 80-90, 70-80, etc. So I write a test that leans a bit on the hard side, and curve it. If everyone does well, or if everyone falls within a narrow margin, I'm not going to force students into the C range though just to satisfy a curve. But it usually comes out to a good curvable distribution."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[
"ratemyprofessor.com"
],
[],
[],
[],
[],
[],
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||
3iyowg
|
why is it so much cheaper to have apparel goods manufactured overseas vs domestic shops?
|
I mean things such as t-shirts, jackets, hats. The price from a typical sweatshirt here vs a manufacturing shop overseas. Why is that? When lots of apparel companies use the same type of shops then sell us the parties marked up 1000 percent.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3iyowg/eli5why_is_it_so_much_cheaper_to_have_apparel/
|
{
"a_id": [
"cukt8gi",
"cuktatl"
],
"score": [
7,
4
],
"text": [
"Because what factories pay a worker in a third-world country is far less than a unionized textile worker will make in the United States.",
"Firstly, the manufacturing process is much cheaper overseas for a number of reason. Mainly it all is based on labor. Salaries are lower, so farming the plants and animals used to make the cloth is cheaper, converting the plant and animal materials into leather or cloth is cheaper, converting that cheaper cloth and leather into clothing becomes cheaper. All of these savings add up to a considerably cheaper production cost.\n\nOverall, it is cheaper to make it in the third world and ship it via cargo container on a freight ship to where they're selling it, than to make it domestically. Companies are fundamentally amoral (neither good nor evil), so they seek out every advantage they can. \n\nAll of these companies mark their prices up so much because they can. Demand is high enough that they can charge you the amount they do and you are still willing to pay that price for that product. If they charge less, they'll sell out too fast; charge too much and they won't sell enough."
]
}
|
[] |
[] |
[
[],
[]
] |
|
8e0bfy
|
how formalin conserves, preserves and fixes organic tissues
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8e0bfy/eli5_how_formalin_conserves_preserves_and_fixes/
|
{
"a_id": [
"dxrgafp",
"dxrgiiw"
],
"score": [
3,
2
],
"text": [
"The technical name is formaldehyde.\n\nFormaldehyde is toxic because it forms \"cross links\" aka \"adducts\" with both proteins and DNA. That is, forming chemical bridges between nearby protein chains , DNA helices, or both. This deactivates these important molecules. So formaldehyde acts to sterilize items.\n\nThis includes proteins and DNA in microorganisms that might otherwise cause decomposition. \n\nBecause formaldehyde is a small, light molecule, it can easily pass through cell membranes in tissues in the body.\n\nIn the context of it's use as a preservative, the cross links also stabilizes sensitive tissues like brain or liver samples. The cross links change the consistency of the tissue to be preserved, making it firmer.\n\nIn small amounts, these cross links can be reversed by specialized enzymes in the body. Indeed, small amounts of formaldehyde are produced by a number of chemical processes in the body. For example, the breakdown of alcohol.",
"It does a few things. As far as fixing goes, the main function is that it crosslinks amino groups on proteins to other nitrogen containing groups by forming -CH2- linkages. This \"links\" all of the DNA (N containing bases), proteins, etc in the cell to form an extremely stable molecular structure. Really gross fact but that's why dead bodies embalmed in formaldehyde have unusually tough skin. It also inhibits enzymes in the tissue that break down proteins and autolyse cells. Finally, formaldehyde is toxic to bacteria. Fixing in formaldehyde will kill any microorganisms present and prevent bacteria from contaminating your sample. Also, like I said it crosslinks nitrogen containing groups, so it can damage/destroy viruses as well (this really applies to vaccines since any virus in fixed sample can't replicate as the cells aren't replicating anymore anyway). Hope this helps!"
]
}
|
[] |
[] |
[
[],
[]
] |
||
aiap4k
|
Did the creation and existence of the Roman praetorian guard somehow affect the rest of the Roman military?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/aiap4k/did_the_creation_and_existence_of_the_roman/
|
{
"a_id": [
"een2h1z"
],
"score": [
6
],
"text": [
"One big impact was that the Roman praetorian guard was the highest ranking and most powerful part of the Roman military for much of the Empire's history. It had constant access to the imperial family, the highest pay, the most prestige and some of the lowest casualty rates in the empire. As such, mostly well off nobles populated the guard (alongside others who the family took a shining to, or just the generally exceptional individuals. The praetorian prefect, in particular, had extensive legal and administrative functions which made them a hybrid civil servant and military leader.\n\n & #x200B;\n\nThanks to this access to important figures and the natural bias of its members, the guard quickly and repeatedly became embroiled in intrigue and plots. More emperors than worth counting became Barracks Emperors, meaning Emperors who took the purple thanks to the army rather than the senate or from inheritance. Many were acclaimed specifically thanks to the praetorian guard, including Caligula, Otho, and Vespasian. The habit of the military 'raising up' Emperors is linked to the Praetorian guard's inclination to raise Emperors themselves.\n\n & #x200B;\n\nFinally, the praetorian guard directly led or intervened in military battles or campaigns that the rest of the Roman military undertook. Notable examples include in revolts in the 1st century AD accompanying Germanicus, in the Year of the Four Emperors, and the Marcommanic Wars. However, the guard became less and less engaged in military affairs from the third century onwards - many prefects were recruited from the class of lawyers rather than experts in war. Diocletian began rapidly weakening the power of the prefecture, until they were eventually disbanded and wholesale reform of the army took place in the late Western Roman Empire's history."
]
}
|
[] |
[] |
[
[]
] |
||
6u6mey
|
how does pain dissipate so quickly after the initial shock?
|
For example, i got a scratch today which stung badly for about 20 seconds before it stopped hurting completely. the scratch was still there and starting to bleed, so obviously the damage hasn't be healed, but what actually happens to the nerves that cause the pain to stop being felt?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6u6mey/eli5_how_does_pain_dissipate_so_quickly_after_the/
|
{
"a_id": [
"dlqe3p8",
"dlrr0x7"
],
"score": [
3,
2
],
"text": [
"The pain was in response to the act of getting scratched. After that, the damage is already done, so the nerves will only register pain if you touch the wound or get another injury.",
"The body also releases endorphins, a sort of natural opioid, to combat the pain.\n\n_URL_0_"
]
}
|
[] |
[] |
[
[],
[
"http://altered-states.net/barry/newsletter260/"
]
] |
|
20y9dv
|
What is the advantage of Lebesgue integration over Riemann integration?
|
Are there applications in which only one definition is defined/useful? Additionally, are there any situations in which the Riemann definition would be preferred?
|
askscience
|
http://www.reddit.com/r/askscience/comments/20y9dv/what_is_the_advantage_of_lebesgue_integration/
|
{
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"cg7zqfm",
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3
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"text": [
"Every Riemann-integrable function is also Lebesgue-integrable, but not vice-versa.\n\nExample: f(x) = 0 if x is rational and 1 if x is irrational.\n\nThe Riemann integral of f from x=0 to x=1 is undefined, but the Lebesgue integral is 1.",
"Riemann definition is preferred for simple application of integration where integrals are computed and approximated. So for situations where you just need to deal with rates of change and integral of continuous functions, Riemann integration is the way to go. It has an easy geometric interpretation (area under a smooth curve) and a readily available toolbox (Fundamental Theorem of Calculus).\n\nOn the other hand, Lebesgue integral is very flexible, it can be applied for other spaces and for other irregular functions (Riemann integral is defined by partition of a line, so the space being considered must be Euclidean). Grad students have to learn Lebesgue integral to know how to prove some rather nice theorems (dominated convergence theorem, monotone convergence theorem come to mind) and there are applications of Lebesgue integration in probability, analysis, etc. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
6mmxen
|
why does water expand when it becomes solid even though particles in solids are closer together?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6mmxen/eli5_why_does_water_expand_when_it_becomes_solid/
|
{
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3,
2
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"text": [
"It's the shape of the molecules that Ice is made of that cause this. Water molecules are a little 'free-flowy' but ice molecules make a ridge shape with lots of open space, so they expand.",
"Water forms a lattice structure as it freezes into ice, leaving a relatively large amount of space between the molecules and causing it to expand.",
"Water actually has about a dozen different crystal phases (technically: \" Allotropes\") most are only stable at high pressures and low temperatures. That is, ways that water molecules can arrange themselves to form a solid lattice structure.\n\nThis is the same thing as how pure carbon can take on several forms, graphite sheets, diamond, hollow soccer ball shapes, and long thin \"nano-tubes.\"\n\nMost of water's allotropes are actually denser than liquid water.\n\nIt's really just an odd quirk that the crystal arrangement that is most stable at high temps and low pressure, has large gap between the molecules. This makes it less dense."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
nto4u
|
why is cutting spending to balance a budget during recession a bad thing?
|
I've read several posts referring to the GOP approach to cutting spending during the current US Recession as a bad thing when attempting to balance the budget.... why is this?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/nto4u/eli5_why_is_cutting_spending_to_balance_a_budget/
|
{
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"c3buhuw",
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"c3bvpc5",
"c3bvuou"
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4
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"text": [
"Cutting spending can mean more indirect methods of balancing the budget - in addition to eliminating direct government expenditures, tax breaks, various subsidies, and incentive programs have been targeted.\n\nWhat this ultimately does is reduce aggregate demand levels and stalls economic growth. The government, like it or not, pours enormous amounts of money into the economy, and it would be disastrous to reduce this in a recession, where demand levels are already below optimal levels.",
"Gross domestic product (GDP) is a common economic indicator, or something that the news like to talk about.\n\n > GDP = Consumption+ Government Spending + Investment + Net Export.\n\nSo in our current situation where Consumption (C) and Investment (I) is pretty low, if we cut government spending our GDP will take a further hit. Also, there's a ripple effect after the cuts where it further lower C and I.",
"Soup lines getting long? Better start cutting back on the soup!\n\nIt should be more along the lines of:\n\nSoup lines getting long? Better start finding a way to help people that doesn't ensure more people will be homeless.",
"The big Keynesian fear is a deflation spiral. Try [wikipedia's](_URL_0_) entry on the subject.",
"Cutting spending can mean more indirect methods of balancing the budget - in addition to eliminating direct government expenditures, tax breaks, various subsidies, and incentive programs have been targeted.\n\nWhat this ultimately does is reduce aggregate demand levels and stalls economic growth. The government, like it or not, pours enormous amounts of money into the economy, and it would be disastrous to reduce this in a recession, where demand levels are already below optimal levels.",
"Gross domestic product (GDP) is a common economic indicator, or something that the news like to talk about.\n\n > GDP = Consumption+ Government Spending + Investment + Net Export.\n\nSo in our current situation where Consumption (C) and Investment (I) is pretty low, if we cut government spending our GDP will take a further hit. Also, there's a ripple effect after the cuts where it further lower C and I.",
"Soup lines getting long? Better start cutting back on the soup!\n\nIt should be more along the lines of:\n\nSoup lines getting long? Better start finding a way to help people that doesn't ensure more people will be homeless.",
"The big Keynesian fear is a deflation spiral. Try [wikipedia's](_URL_0_) entry on the subject."
]
}
|
[] |
[] |
[
[],
[],
[],
[
"http://en.wikipedia.org/wiki/Deflation#Deflationary_spiral"
],
[],
[],
[],
[
"http://en.wikipedia.org/wiki/Deflation#Deflationary_spiral"
]
] |
|
2c03r9
|
Help needed in deciphering WWII map symbol
|
I am working on a WWII project specific to Operation Dragoon, and in reviewing the period maps for beach 264-A (Camel Green Beach, landing zone for the 36th INF), I see several instances of this map symbol linked below:
* _URL_0_
However, this symbol is conspicuously absent from the map key, and I'm trying to figure out what it is. It's worth mentioning that several of these have numerals next to them which (I think) usually indicates how many guns are present at [Map Symbol].. Is this maybe meant to show a house with a gabled roof with 'x' amount of [weapon type] emplacements, or something else entirely?
Thanks!
Edit: clarity
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2c03r9/help_needed_in_deciphering_wwii_map_symbol/
|
{
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"cjb3seg",
"cjb7ysx"
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"score": [
2,
2
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"text": [
"*If* its actually a unit marker, its probably a [maintenance unit](_URL_1_). However, It seems suspicious that there is no unit markings, no size, and no unit identifies. For example, [this](_URL_0_) symbol is what I would typically consider to be a unit marker. It is evident, by the information provided around the symbol (as well as symbol itself) that we are looking at the 14th Mechanized Brigade. Your map doesnt include any of this information. Thus, Im suspicious. \n\nFurther, lets consider the rest of the map. I cant find any other units, even in the landing zones. Typically, the zones should be capped by a Symbol designating the unit intended to effect that landing. There is none of that. But the map is *filled* with artillery symbols, and unit numbers for *those* units. Then you have all that garbage on the beach, which kind of looks like a wall. Finally, there is are those zones, which have lines inside irregular boxes. I think youve mistook one of these for a unit symbol. *But*, I dont think those are unit symbols at all. Instead, I would think that this is a map of German defenses and artillery units in the area. The red lines along the beach are probably walls and fortified positions, while the cannon looking symbols are batteries. The boxes are hard to identify without proper context, but I would think theyre probably German garrisons, bases, marshalling areas, motor pools, dumps, ect. The number could be number of men, vehicles, buildings under the box, or anything really. Without know for sure *what* the the box represents, its impossible to say. \n\nBut all this is really a shot in the dark without context. If I were you (unsolicited advice inbound) I would try and find out *what* the map is. Where did you get it? Do you have any other associated paper work? Any similar maps? ",
"I don't have access to any WWII-era field manuals, but the system they used then serves as the basis for what's still used today. Which is to say that it's largely an expansion of what they were doing in WWII, and so a current reference should still contain descriptions for the older symbology.\n\nThe current Army Field Manual that details this is [FM 1-02, OPERATIONAL TERMS AND GRAPHICS](_URL_0_)\n\nChapter 5 details what goes into unit markings. However, I don't think this is a unit marking. Here are my reasons:\n\n1. The rectangle indicates a friendly unit. But it's placement and color would imply that it's unlikely to be friendly.\n2. It doesn't quite match any existing unit type indicators:\n * The infantry symbol is a large \"X\" going from each corner to the opposite corner. The mystery symbol clearly has a horizontal element that the infantry mark doesn't contain.\n * The maintenance symbol is supposed to be a stylized wrench in the center of the box. I can imagine that someone might be sloppy and have the ends of the wrench extend out to the edges of the box, but I can't imagine that someone would repeatedly draw the lines carefully out to each corner. The symbol is clearly deliberate, not lazy.\n * There aren't any size indicators or text containing the names of the units. \n * It's very close to the symbol for \"Theater/Echelons Above Corps Support Element\". However that mark doesn't have the horizontal center bar on it. The generic mark for a supply unit does include a horizontal line, but it's off-center toward the bottom rather than centered.\n3. But most damningly, there's at least one appearance of this symbol that isn't a rectangle. Instead it's clearly a deliberately drawn irregular 4-sided shape. It's in the 6042 grid square on the map, east-southeast of the town. You can also see a very large one in the upper-left hand corner of the map, and another one that gets cut off in the center-top of the map. This implies to me that it's some sort of graphic control measure defining the terrain in some fashion. Some ideas:\n * If the 4 edges of the symbol indicate the perimeter of the terrain being defined, then what's left looks very much like the marker for a lane (i.e. some specific path through an obstacle). This is a long-shot... I don't think this is the answer.\n * It's an indicator of a base or fixed facility of some sort\n * The legend says that the info was provided by the 8th Fleet N-2 - so maybe these are symbols specific to naval usage?\n"
]
}
|
[] |
[
"http://i.imgur.com/Ntb39lH.png"
] |
[
[
"http://www.warandtactics.com/Images/nato_tacsymbs/1movement.gif",
"http://army.ca/wiki/images/3/37/Map_Symbols.jpg"
],
[
"http://armypubs.army.mil/doctrine/DR_pubs/dr_a/pdf/fm1_02.pdf"
]
] |
|
ebx0ic
|
why can icicles form on power lines, even though the current running through them should be strong enough to melt them?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ebx0ic/eli5_why_can_icicles_form_on_power_lines_even/
|
{
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"text": [
"Electricity 9nly creates heat if there is a lot of electric resistance. If there was a lot of electric resistance in power lines not only would they heat up the surroundings a lot people wouldn't get any power. So the labels have very little electric resistance. Try touching your average power cable after for example using your PC the whole day the kable will be just as warm as it's surroundings.",
"Power lines are made with thick wires and use high voltage to limit the energy lost as heat on the way to homes and businesses.",
"It depends on the current though the lines, the size of the lines and the insulation on them. It can for example be possible for burglers to identify unocupied houses by looking at the amount of ice on the power lines. If a house is not occupied it will use less power and the lines will be cooler and can therefore collect more ice. It is also common to see new high voltage power lines have more snow and ice on them as the power company have invested in heavier guage wires and more insulation then the old ones. They will also fly around the lines with heat cameras to identify spots in the wire where there is a bad connection or were strands in the wire have broken as these spots will be hotter then the rest, it can also be possible to see these as areas without snow and ice even though the wires around the area is covered in ice.",
"Actually, power lines don't have very large currents running through them. Instead, they use very high voltage to transmit the large amount of power. Since watts=volts x amps you can transmit 1 million watts at 500,000 volts and just two amps, instead of 120 volts and 8300 amps. There is a good reason to use high voltage and low amps: it cuts down on losses due to heating, which would not just melt ice but cost money in lost power. Power line losses can be figured as I^2 R or the square of the amps times the resistance in the wire, so clearly you want the least current possible thus high voltage.",
"The electricity isn't really doing anything in those wires except passing through, that's why birds can sit on them and not get electrocuted. \n\nWhen hot wire A and neutral wire B get to the destination and start doing some work, THAT is when things heat up. And even then, if the wires are large enough, they won't really heat up. Only undersized (i.e. overworked) wires tend to heat up."
]
}
|
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[
[],
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] |
||
y0nur
|
Why was Poland never paid reparations for WW2?
|
Over 6 million Polish citizens dead (including Polish Jews), cities like Warsaw [purposely](_URL_0_) destroyed to the ground, and whole libraries burned.. I really don't see how Poles were never given any kind of reparations.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/y0nur/why_was_poland_never_paid_reparations_for_ww2/
|
{
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],
"score": [
5,
6
],
"text": [
"Well, the Allies tried doing reparations after World War I and that didn't turn out so well....\n\nBut more completely, reparations from Germany in WWII was largely by using German POWs as [forced labor](_URL_0_) . There are also some territorial changes after the war were German territory was given to Poland, although the Soviet Union kept the part of Poland it annexed in 1939 and I doubt the Soviets ended up paying reparations to Poland for their part either.",
"Because Poland took over a big chunk of Germany after the war and waived all claims against Germany in return for a percentage of Soviet reparations. The Soviet Union \"provided military protection\" to Poland and said that made things even. \n\nBasically, Poland and Germany agreed to drop the matter because then you get into compensation for all the Germans kicked out of Danzig/Gdansk and it all just turns into a big, big mess."
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Planned_destruction_of_Warsaw"
] |
[
[
"http://en.wikipedia.org/wiki/Forced_labor_of_Germans_after_World_War_II"
],
[]
] |
|
3rq3a9
|
why is america constantly freaking out about healthy lifestyles and the obesity epidemic, but then crucifying people for fat shaming and not having fat models, actors, actresses, etc.?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3rq3a9/eli5_why_is_america_constantly_freaking_out_about/
|
{
"a_id": [
"cwqby22",
"cwqc1fl"
],
"score": [
3,
2
],
"text": [
"America is a massive country with lots of people. Unlike some groups *cough* reddit *cough*, these people do not agree on everything and have varied opinions.",
"Probably the same person criticizing fat shaming isn't the same one designing ads and casting models/films? There is more than one person in US, you did know that, no?"
]
}
|
[] |
[] |
[
[],
[]
] |
||
1pepmo
|
When, in recent history, have Democrats made a terrible mistake that affected the United States?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1pepmo/when_in_recent_history_have_democrats_made_a/
|
{
"a_id": [
"cd1kn08"
],
"score": [
2
],
"text": [
"Removed. This is both loaded, and a poll-style question."
]
}
|
[] |
[] |
[
[]
] |
||
129vld
|
How hard would it be to open a soda bottle in space?
|
I mean a bottle that you need a bottle opener to use, not the twist caps. Do soda bottle made on Earth have air under their lid or a vacuum? How would this affect the difficulty?
|
askscience
|
http://www.reddit.com/r/askscience/comments/129vld/how_hard_would_it_be_to_open_a_soda_bottle_in/
|
{
"a_id": [
"c6te1f9",
"c6tebs1"
],
"score": [
2,
9
],
"text": [
"Soda bottles are under pressure, not vacuum. \n\nIf you brought a pressurized soda bottle / can into space it may explode due to the pressure differential and the weak plastic or glass. If not, it would be quite easy to open due to the very high pressure differential, but upon opening the compressed gas would boil into space and most likely take all of your soda with it.\n\nIf you had a vacuum bottle (such as a bottle of fruit juice), there would still be a massive pressure differential in space as we cannot actually create a very strong vacuum in bottles / cans without risking them being crushed by air pressure.\n\nHere's an experiment. Take an empty standard 2 Liter plastic soda bottle and fill it 1/2 with boiling water. Wait a second or two and place the cap on tightly and let the water cool.\n\nWhat will happen is you will create a partial vacuum in the bottle as the water cools (steam creates higher pressure in the bottle which becomes low pressure when the steam returns to liquid state). This partial vacuum will crush the bottle. ",
"I don't think the pressure difference would really be that huge as you guys are making it out to be. Most sodas, when shaken, have probably around 1.5 bar or more (compare their resistance to poking with a bike tire). They will not simply explode if you increase the pressure difference by half a bar.\n\nAfter some reading, typical maximum pressures (differences?) for bottles seem to be around 5 bar. So bringing them into space should not make a huge difference.\n\nAfter opening, things look a bit different though."
]
}
|
[] |
[] |
[
[],
[]
] |
|
iidn1
|
How do bugs hibernate for so long if they have a short lifespan?
|
I always wondered how bugs come back every year and I kind of assumed they migrated. Apparently some do but also some hibernate, like mosquitoes. But I only see them during the summer. How do bugs with short lifespans not go extinct every winter?
|
askscience
|
http://www.reddit.com/r/askscience/comments/iidn1/how_do_bugs_hibernate_for_so_long_if_they_have_a/
|
{
"a_id": [
"c2402cu"
],
"score": [
3
],
"text": [
"I'll address mosquitoes specifically, they do one of three things:\n\n1. \nMosquito females lay eggs in late fall. They lay them in moist ground, which promptly freezes at the start of winter. This freezing renders the egg dormant, and little to no biological activity happens at this stage. In the spring, when conditions are more favorable, the eggs become active again and proceed to develop into larvae.\n\n2. They hibernate...ok not quite but they do live through winter in a very inactive state. Only female mosquitoes are alive in the winter (males die after mating). Metabolism drops and they hide in things like dead logs or in that hole in the tree your local squirrel hangs out in during the winter. When it warms back up, they first look for blood (convenient if they're living with an animal) and then lay their eggs in the freshly thawed pounds, pools and puddles abundant in the spring. \n\n3. For some species of mosquito they enter diapause, which suspends development and essentially halts metabolism. When the weather warms up, metabolism starts again and eventually so does development."
]
}
|
[] |
[] |
[
[]
] |
|
g36kl7
|
why do children and teens grow in spurts or bursts, rather than continuously?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/g36kl7/eli5_why_do_children_and_teens_grow_in_spurts_or/
|
{
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5370,
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"text": [
"I think you are confused.\n\nChildren do indeed grow continuously, with growth spurts being a \"sometimes\" indecent. Toddlers can have growth spurts, and even people who are older can get them. My brother hit a major one about a year and a half ago, now he almost as tall as me. He was 22 at the time.\n\nGrowth spurts happen when your body (doesn't always know if its the right time, mind you. This is why we get aches and pains during them) pumps excess hormones and energy to your system to help you go through the natural process of puberty, which alone makes you grow. With both things working side by side, you get these very noticeable spots of growth, getting called growth spurts, even though they are normal and don't happen *often* (often in terms of your entire development into an adult. Happens much more often in terms of your early development i.e Teens and children.)\n\nNow, for the why. We really don't know the exact reason why out bodies do this. But most tend to believe it has to do with how your body needs to adapt to your environment, and trying to get you as physically fit to defend ones self, since humans are born defenseless/helpless unlike a lot of other animals.",
"Hormones. \n\n\nGrowth Hormone is released in cycles, you get bursts of it during sleep, so kids growing up overnight is actually kind of true. \n\n\nGrowth hormone secretion is also increased by a number of other factors, most notably from testosterone and estrogen, which are increased during puberty. Other causes of increased growth hormone would be eating (insulin and glucagon both increase growth hormone), and exercise.\n\n\nBut like someone else already said: these things are occurring pretty consistently (that growth hormone increase is occurring every night), so the 'bursts' we see are probably just our own perception when we see that someone's grown an inch and we hadn't realized it.",
"Few of these answers address the \"why\" component, so I'll give this a shot. Biological anthropologists have debated this for quite a long time and it's an interesting concept because very few other animals have similar periods of slow growth followed by \"growth spurts\".\n\nYou're right that growth is punctuated in humans. Humans undergo rapid growth until around the age of 4, then much slower growth until around the age of 12 when humans undergo a period of rapid growth for a few years before growth gradually slows to a stop (usually around age 20). The best explanation for this has to do with brain development. Kids have big heads, and your brain is basically done growing (about 90% done) by the time overall growth slows around age 5. Brain growth isn't everything, though. It's just a lump of meat until you train it. The period of slow growth is hypothesized to give you a long window to learn things without needing the same amount of resources as an adult. In groups where this occurs, you'd have smaller, immature kids running around who are easier to feed until they're smart enough to be sort of useful at which point they grow into full-sized adults.\n\nThe ELI5 version is, kids are stupid and it's easier to teach them stuff when they're small. Keeping them small a little longer is advantageous in the long run.\n\nEdited to add: the ages I've cited are approximate. They vary by sex, nutritional status, stochastic variation, and a bunch of other factors. Your mileage may vary, but the overall pattern of an adolescent growth spurt is a human universal which occurs in all populations. It seems to be hardwired in.",
"One possibility is that the hormones associated with growth inhibit other necessary processes, such as the immune system. \n\nFor example the hormones associated with wakefulness/alertness, such as cortisol and adrenaline, can and do suppress the immune system, but the immune system is allowed to activate during sleep and clear infections. Anabolic hormones like testosterone also suppress the immune system, so the body drops its testosterone levels when there’s an infection. It could be that the body would end up neglecting other really vital processes if it was growing all the time. \n\nI saw the Netflix documentary featuring the scientist who found that babies measured weekly grow at a steady rate but measuring daily reveals a surge in growth one day of the week and little growth on the other days. I’m thinking that might be what this question is about. \n\nNow imagine that these growth hormones deflect energy from the immune system during the time it’s supposed to be most active: at night. Would it be better to weaken the immune system a little bit every day, or allow it to be highly active for 6 days a week and take a little bit of a break on the 7th day when there’s a surge of bone growth? \n\nIf an undetected infection started building on one day, the immune system could play catch-up the next day. The infection wouldn’t have a chance to get very far. And of course a baby’s body could easily just skip its little growth spurt for the week if it’s actively sick. \n\nThis could work with other processes too: digestion, mental activity, physical activity, etc. If a baby loses its ability to absorb nutrients as well on the day it’s growing—and it needs those nutrients to grow—then it’s pretty obvious why it would have to shut that process off to stock up on protein and calories until the next spurt.\n\nI don’t know the exact answer for you or even if the exact answer is known to science at all, but this sort of balancing priorities is the reason why living organisms in general have a lot of cyclical processes.",
"Insulin-like growth factors I and II are regulated by Growth Hormone. Their action on a wide variety of body tissues and cell types control coordinated growth throughout life. They also explain the difference in size between tea cup and standard poodles (and other animals of course such as fish). It is the combined effects of pulsatile GH release and IGF action that controls growth spurts. Source: my Ph.D thesis.",
"It's not well understood. In short, it's likely that you evolved in such a way as to accumulate resources (fat/minerals/vitamins) during slow-growth periods that are then consumed to fuel fast-growth periods. If you grew too fast all the time, you wouldn't naturally have enough food to sustain the growth and you might waste energy resources producing growth hormones at a time when your body simply doesn't have the resources to do anything about it. Sustained food availability is something the human species didn't have until maybe 100 years ago.",
"As the puberty hits growth hormones are released thes hormones will cause sudden increase in length of bones(specially long bones ie. Arms and legs).therefore many teens just after puberty body shape looks somewhat disproportionate",
"This is to be a very broad scope explanation. Biologically, it would be energy inefficient to undergo both a continuous and explosive growth period. That means a constant source of high energy food, and water to hydrolyze all those reactions. Instead you see spurts of activity above the mean. The current pattern is what worked for our species. Other modus operandi were weeded out through natural selection.",
"The number of people straight up arguing about this like it's a semi-friendly debate with just a smidgen of veiled hostility is equal parts humorous and exasperating with just a dash of nauseating thrown in.",
"There are two different things that are both called \"growth spurts\".\n\n1) children have months where they grow significantly faster than others.\n\n2) if you zoom in and measure height each day, you find that the growth is [really only happening on a subset of days](_URL_0_).\n\nThe former may be explained by bursts of hormones, and the latter is not well understood.",
"I see you phrased your question as a why, not a how. Very well done, though it's much trickier to answer. \n\nGrowing in spurts is not unique to humans. It's actually how almost all organisms grow during development, so this question is much broader than human biology. Why should any organism grow in spurts vs continuously? The answer is related to 1 food uncertainty, and 2 the benefits of regulation.\n\n1. If food comes in discontinuous spurts, it is best to concentrate growth (resource intensive) during the times food is most abundant/secure. This is why plants with seasonal access to light only grow in that season, and why tropical plants grow nearly continuously (though still a difference between night and day growth rate).\n\n2. Regulation of growth is good in general because it is one of the most complex things an organism can do. Growth has the highest potential for things to go wrong, grow out of control, or grow incompletely. Any one of your 35 trillion cells could start growing uncontrollably if just the right failure in regulation occurs. It then follows that you would want to limit growth only to the places and times it must occur to prevent cancers or other failures that become more likely when every cell in the body is allowed to grow continuously."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://www.washingtonpost.com/archive/politics/1992/10/30/growing-up-overnight/744a0019-b235-438b-b572-790ce2e4784e/"
],
[]
] |
||
6zkxgb
|
why do some people have the inability to float in water?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6zkxgb/eli5_why_do_some_people_have_the_inability_to/
|
{
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"dmw2jx7",
"dmw2olm",
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"dmw3xhj"
],
"score": [
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],
"text": [
"You may have hard that humans are made up of mostly water. About two thirds is the ballpark. That neither helps you sink or float since there's no difference to the surrounding water, so it's up to the remaining one third to determine if you can float. \n\nIf you've ever made soup you know that soup bones sink, meat/muscle sinks, and fat rises to the top, air and bubbles also rise to the top, which explains why having a lungful of air helps you float. If the floaty bits outweigh the sinky bits, you'll tend to float. Someone who's all muscle, or all skin (leather, by itself doesn't float) and bones will tend to sink.\n",
"(Physics lover here)\n\nEssentially, the reason we can float at all is that when we spread our weight out, the buoyant force from the water is greater than the weight of our body on the water. However, if there's not enough surface area to allow the pressure to push up on your body, you will sink. I think that some people simply cannot stretch out enough to float while simultaneously keeping their head above the water. While the average human density is 985 kg/m^3 compared with water's 1000 kg/m^3, some people are above that average, pushing them over that 1000 kg/m^3 limit. As a result, it doesn't matter what they do - they will not float. \n\nHope this answers your question!",
"It's a matter of bone density (can be heavier or lighter than water), muscle mass (heavier than water), and fat content (lighter than water). People that exercise a lot tend to have denser bones, more muscle, and less fat - so they are denser than water and will sink.\n\nSince there's a number of factors there, you can't automatically blame someone being good at floating on their fat content (though in some cases it's painfully obvious).",
"why are some people different?"
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
12q9xt
|
What is the ideal population of humans on Earth, in the interest of the sustainability of resources and the environment? Will global population growth slow as more countries become industrialized?
|
askscience
|
http://www.reddit.com/r/askscience/comments/12q9xt/what_is_the_ideal_population_of_humans_on_earth/
|
{
"a_id": [
"c6x8nhp"
],
"score": [
2
],
"text": [
"There is probably no universal optimum number...\n\nA lot of the problems humanity has are caused by mismanagement and waste of the resources we have. I'd like to see a figure based on how humanity currently fails to properly co-operate and manage everything, and a figure in some utopian future where food, water, land etc are all used efficiently and traded fairly."
]
}
|
[] |
[] |
[
[]
] |
||
uvtk3
|
every night the same question! why do most electric fans start on high?
|
Every fan I have ever owned goes from off, high, medium, low. Why?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/uvtk3/every_night_the_same_question_why_do_most/
|
{
"a_id": [
"c4z04xo"
],
"score": [
4
],
"text": [
"_URL_0_\n\nLinking the thread so credit goes where it is due"
]
}
|
[] |
[] |
[
[
"www.reddit.com/r/explainlikeimfive/comments/oh89i/eli5_why_every_fan_ive_ever_seen_has_the_speed/"
]
] |
|
32e25w
|
is there a possible way to speed up the process of ridding a location of radiation? for example, after a nuclear accident such as in japan or at chernobyl.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/32e25w/eli5_is_there_a_possible_way_to_speed_up_the/
|
{
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"cqacbry",
"cqacc88",
"cqaevtj",
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2,
2
],
"text": [
"It's important to understand the difference between radiation (energetic rays and particles) and contamination (finely divided bits of material that emit radiation). Radiation is going to occur as long as contamination is present, until said contamination decays. Can contamination be removed? Yes. It's just very expensive.",
"We do not have any process to cause radioactive materials to decay faster. \n\nThat means the best we can do is try to either seal it up, or move it somewhere else then seal it up. One way is to use certain types of plants which like to absorb radioactive materials. It makes the plants radioactive, but it sucks the radioactive material out of the soil. Then you move the plants to a facility somewhere else. \n\nIf we had the ability to make radioactive materials break down faster, we would be using it to get rid of the spent fuel. ",
"I'm pretty sure they've made some advances using mushrooms to clean up some of it. here's an article _URL_0_",
"You can remove the loose radioactive materials that are emitting radiation and move them elsewhere, as [the hazmat crews in Japan did with a special gel](_URL_0_).\n\nAside from that there's no way to make the radioactive materials non-radioactive except to let it decay naturally."
]
}
|
[] |
[] |
[
[],
[],
[
"http://discovermagazine.com/2013/julyaug/13-mushrooms-clean-up-oil-spills-nuclear-meltdowns-and-human-health"
],
[
"http://www.popsci.com/science/article/2011-05/cleaning-japans-radioactive-mess-novel-new-blue-goo"
]
] |
||
1uccjr
|
why do you have to tell yourself to chew(or anything else), but you don't have to tell yourself to breathe?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1uccjr/eli5why_do_you_have_to_tell_yourself_to_chewor/
|
{
"a_id": [
"cegm5sm",
"cegpb8b"
],
"score": [
7,
3
],
"text": [
"You need to breathe literally **all the time**. You only need to chew for a maximum of an hour a day, generally much less. If you had to consciously breathe or beat your heart, then that would add extra strain to your cognitive power and reduce the amount of things you could do at once.",
"Thanks for making me go into \"Manual Breathing mode\" ... cunt "
]
}
|
[] |
[] |
[
[],
[]
] |
||
690p8f
|
why kid's remedies taste good, while adult's remedies taste so bad?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/690p8f/eli5_why_kids_remedies_taste_good_while_adults/
|
{
"a_id": [
"dh2qyxj"
],
"score": [
3
],
"text": [
"They add sugar and flavorings so you can get the fussy brats to take them for their own good.\n\nAdults understand why it is important to take medicine and are mature enough to put up with a little bad taste."
]
}
|
[] |
[] |
[
[]
] |
||
5ia18k
|
why is kayne west such a controversial figure ?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5ia18k/eli5why_is_kayne_west_such_a_controversial_figure/
|
{
"a_id": [
"db6jdj1",
"db6kjom"
],
"score": [
8,
4
],
"text": [
"Guy who occasionally makes amazing music regards himself as a much bigger figure than he actually is because he says that's the type of mindset an artist needs to have.",
"Kanye West is controversial because enough people view him as erratic enough to ask why he's so controversial. Besides people's unwavering interest in celebrities, he's just a narcissistic drama queen, whom I suspect has extreme delusions of grandeur, and he just happens to have a lot of people's attention.\n\nHumans are weird with or without people watching them"
]
}
|
[] |
[] |
[
[],
[]
] |
||
1gklys
|
why does a circuit need to be connected to ground in order to work?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1gklys/eli5_why_does_a_circuit_need_to_be_connected_to/
|
{
"a_id": [
"cal4lww"
],
"score": [
5
],
"text": [
"First of all: electrical engineers will use the term *ground* for electrical connections to the soil ([example](_URL_0_)), but also for a return path of electricity that is *not* connected to the earth in any way (e.g. in your mobile phone).\n\nThe first one is not required for a circuit, but improves the safety of electrical appliances at home. The second one (return path) however is necessary because electrical energy or current is just a movement of electrons. Electrons are not \"used up\" in a circuit, but move from a place where there are many of them (e.g. minus electrode of a battery) to a place where only a few electrons are.\n\nSo in a simple circuit electrons would enter e.g. a lightbulb through one wire, doing their thing in the filament (i.e. making it glow brightly) and then leave through the second wire."
]
}
|
[] |
[] |
[
[
"http://upload.wikimedia.org/wikipedia/commons/7/7d/HomeEarthRodAustralia1.jpg"
]
] |
||
3e69vw
|
how is a cpu heatsink more effective than just having a fan blow straight over the surface of the chip?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3e69vw/eli5_how_is_a_cpu_heatsink_more_effective_than/
|
{
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"ctbvzsv",
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"text": [
"Air is not a very good heat conductor. The heat sink \"fixes\" that by transferring the heat from the CPU to a bigger surface (which is why it has ribs). \n\nAlso [search, damn it!](_URL_0_)",
"In short, the purpose of a heat sink is create a larger surface area that is in contact with the cooling mechanism, i.e. air, water etc. This translates into more efficient cooling than just the chip itself, which has a much smaller surface area.",
"A little bit of an ELI10 answer\n\nImagine the heat generated by the CPU to be represented by a stream of cars.\n\nAir conducts very badly and can be seen as a narrow one lane dirt road where all the cars have to drive on. Putting a fan on the CPU might upgrade the road to asphalt and make the cars drive away faster but its still a narrow one lane road.\n\nNow imagine a heatsink being an efficient highway system where there are many off ramps to the same one way road (air) however when the cars leave the CPU they first get to drive on this fast high efficient highway before taking one of the many off ramps. This way the cars can leave the CPU quickly and then spread themselves thin throughout the various off ramps. This way more cars can leave the CPU quicker, this less of a traffic jam (heat build up) at the CPU, this a lower temperature CPU.\n\nIt should also be noted that because a heatsink is much larger than the CPU head the heat is also dissipated onto more roads. (Since a larger volume of air comes I'm contact with the heatsink) \n\n"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/explainlikeimfive/search?q=heatsink&restrict_sr=on"
],
[],
[]
] |
||
2ry2gc
|
What influence did religion have on the Cold War?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2ry2gc/what_influence_did_religion_have_on_the_cold_war/
|
{
"a_id": [
"cnl0ina"
],
"score": [
2
],
"text": [
"There was a similar question asked specifically about the US, just yesterday:\n\n_URL_0_\n\nYou might find the answer you're looking for there, otherwise; are you asking for a broad strokes answer, or is there a specific aspect in which you're particularly interested?"
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/AskHistorians/comments/2ruzcm/questions_about_us_religion_and_the_cold_war/"
]
] |
||
1anwnc
|
I recently read that electrons move through graphene as if they have no mass. Is this true? If so, is it known how or why it happens?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1anwnc/i_recently_read_that_electrons_move_through/
|
{
"a_id": [
"c8z834b",
"c8z8xtn",
"c8z93h8"
],
"score": [
2,
2,
3
],
"text": [
"Are you sure you read that or did you hear it on the Big Bang Theory TV show?",
"This is true, and yes, it is known why this happens, but it is not easy to explain in a non-technical way. Here is a very [general description](_URL_0_) of what's going on. The basic idea is you have to look at the equations of how electrons move in the presence of this two-dimensional structre (a layer of carbon atoms arranged in a hexagonal lattice).",
"Electrons behave quantum-mechanically. In that model, they _do_ have a mass, and essentially move as if they had their rest-mass (as the effects of relativity are fairly negligible here) \n\nWhat they _don't_ have is an \"[effective mass](_URL_1_)\", which in this context is a concept belonging to a particular model, giving it a quite specific technical meaning. (so, not to be confused with saying they 'effectively have no mass') \n\nThis is a \"semi-classical\" model, where you're treating the electrons _as if_ they obeyed Newton's law of motion (F = ma) in response to an electrical field. (Which, as quantum-mechanical things, they _don't_ actually do) The 'effective mass' here is what their 'mass' would be if they did. For an electron that's a free particle in a vacuum (circumstances where it does not behave quite as 'quantum-mechanically'), this does end up equating to the actual mass. But there's no reason it'd need to do so for a bound electron here. The 'effective mass' is in fact dependent on the direction in which the electrons are moving, and has no problems being zero or even negative. For instance, at a zone boundary in some material, the electrons may have a negative effective mass, as they reflect off the boundary when a field tries to pull them in that direction. \n\nIn simple terms, there's nothing terribly mystical about effective masses that don't match the actual mass. But it does have a direct relationship to one of the interesting and distinctive properties of graphene, namely its lack of a [band-gap](_URL_0_). But it's not really true that they 'act as if they have no mass' in general, just that they 'act like they have no mass when treated like classical particles responding to an electrical field'.\n\n"
]
}
|
[] |
[] |
[
[],
[
"http://www.zdnet.com/how-does-graphene-work-3040093081/"
],
[
"http://en.wikipedia.org/wiki/Band_gap",
"http://en.wikipedia.org/wiki/Effective_mass_%28solid-state_physics%29"
]
] |
||
a2apcj
|
If senate races are staggered in the US, how did the process work when the country was first born? Did some senators get to serve 2 more years and others 4?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/a2apcj/if_senate_races_are_staggered_in_the_us_how_did/
|
{
"a_id": [
"eawpxoq",
"eax3pe9"
],
"score": [
28,
2
],
"text": [
"Basically yes. Per article I, section 3 of the Constitution\n\n > Immediately after they shall be assembled in Consequence of the first Election, they shall be divided as equally as may be into three Classes. The Seats of the Senators of the first Class shall be vacated at the Expiration of the second Year, of the second Class at the Expiration of the fourth Year, and of the third Class at the Expiration of the sixth Year, so that one third may be chosen every second Year\n\n & #x200B;",
"As a follow on question (or two): do we know how this affected re-elections? How many senators in the two year class lost their seats? \n\nWe're any of the two year class from states that took nearly that long to ratify the Constitution?"
]
}
|
[] |
[] |
[
[],
[]
] |
||
2dkr7k
|
when concerts sell out in 10 minutes why doesn't the artist just book a bigger venue so more people can come?
|
Concerts will sell out within minutes for big artists performing at a small venue. Why don't they just play at a bigger one so more people can come. They'd be selling more tickets so it seems like a win win.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2dkr7k/eli5_when_concerts_sell_out_in_10_minutes_why/
|
{
"a_id": [
"cjqew29",
"cjqf05q",
"cjqfuwo"
],
"score": [
4,
2,
2
],
"text": [
"Most of the time they are playing at the largest venue in the area. ",
"Ignoring the issue of the costs involved of breaking the contract with the venue, transferring tickets from one venue to another, and informing tens of thousands of people of a venue change, there are other issues. Venues are booked FAR before tickets are available to the public. Often times, the venue they get is the biggest and/or best one available to those acts. Changing would many times be impossible to do due to other events occurring on the same day. Even if there isn't another event that day, those other venues may be setting up for a future event, and hosting a concert may not give them enough time to set up for that event.",
"*Usually* musicians need to play to shows of [18,000 people or more](_URL_0_) to actually turn a profit, otherwise they're likely to just break even when all the costs (such as travel and lodging) are factored in, or possibly even lose money if they don't sell enough tickets (regardless of the venue size). When popular musicians play at a small venue, even though they would most likely be able to sell enough tickets to fill up a larger venue, it's because the venue is actually paying them a flat-rate to perform there, rather than a figure based on ticket sales. This is pretty unusual however because most small venues can't afford to pay a popular musician enough to compete with the potential revenue they'd generate from ticket sales at a larger venue. Of course, changing venues would also mean breaking contracts, which could incur additional costs as well."
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.npr.org/blogs/therecord/2011/04/07/134851302/the-concert-ticket-food-chain-where-your-money-goes"
]
] |
|
3n9iyw
|
why is everyone stepping down from their positions in government?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3n9iyw/eli5_why_is_everyone_stepping_down_from_their/
|
{
"a_id": [
"cvm1n75"
],
"score": [
3
],
"text": [
"Could you be more specific? From what I can see \"everyone\" isn't."
]
}
|
[] |
[] |
[
[]
] |
|
3ljq1q
|
how do developed countries deal with government corruption very well? how do these governments' differ with third-world countries who struggle with it?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3ljq1q/eli5_how_do_developed_countries_deal_with/
|
{
"a_id": [
"cv6v3dp",
"cv6vnaf",
"cv6xkwh",
"cv70zo8",
"cv7ov7y",
"cv7sasq"
],
"score": [
10,
3,
40,
10,
3,
2
],
"text": [
"They can pay their officials better, and they have the wealth to afford large numbers of police, lawyers and investigators. ",
"They don't. There are very corrupt developed nations. It's cultural. If everyone buys into the system it keeps happening",
"The developed countries used to suffer from huge corruption, and many of the changes in their political evolution over the last few hundred years have been made with the aim of preventing and controlling it. Before it came to be seen as a good thing in itself, democracy was a way to prevent high officials corruptly misusing their positions. Many of the day-to-day features of the developed countries and their governments are there wholly or partly to prevent corruption. This isn't just law enforcement, it's things like the rules by which civil servants are appointed (on the basis of ability not connections); external audits of government spending; appeal courts; transparency about government decisions etc. \n\nThere are also some features that tend to make countries more or less corrupt: inequality breeds corruption - its' no coincidence that the Nordic countries have the lowest levels of both corruption and inequality. Welfare systems and social safety nets also help prevent corruption, because government officals aren't expected to look after their extended family. And secrecy and complexity both encourage corruption: it's easier to get away with it if people can't see or understand what you're doing. One of the big drivers of corruption is where the government gets its revenue. If the government takes it from the population in taxes, then people hold them to account about how it's spent. But if the government takes it from oil or mining companies in as a fee for extracting natural resources, then there's no accountability for what they do with the cash. \n\n Lots of developing countries have never developed the government systems that prevent corruption. They're poor, with high levels of inequality and no social safety nets, no transparency and no auditors, so governments can get away with huge corruption. In many countries it's become a deeply embedded part of the culture, and it's reflected in how poorly the public sector is paid: you might be expected to \"buy\" a job by paying off your boss, and then make the money back by extracting bribes from everyone who uses the service that you're supposed to provide for free. ",
"In the United States our solution was to make corruption legal and call it lobbying. It's working out really great so far.............",
"So it's important to understand what causes corruption. A huge portion of the world inherits it's legal system from Spain, France, Britain, Portugal or some combination thereof. So it's not that those legal systems are inherently corrupting, since not all of them are corrupt. \n\nCorruption comes about when something is worth substantially more than it costs. If I offered you 5 dollars for whatever device you typed your question on, you'd say no- obviously it's worth more than 5 dollars so that's nonsense. If I offered you 5 million many people would try and interject and offer me theirs, they'd trip over themselves to get a piece of that 5 million dollars. Because you'd be a fool not to take the 5 million, and then spend 500 or whatever of it to replace the thing I gave you. \n\nNow lets extend this to more complex systems. Lets say your country produces 1 million barrels of oil or a million tonnes of iron or something. Those are traded on the world market, and they have a value people will pay to get it. But the average worker say gets 5 dollars a day or 2 dollars or something, the average politician 20 000 (for example). So your company and mine both want in on this oil/iron/etc. We know we can produce it for a tiny fraction of the market value, and since labour is cheap there's no point in paying more. But what we need is to be *allowed* to do so. So... you offer a local politician 100k, I offer him 200k. He takes the 200k, and now lets my company in to extract millions of dollars in stuff. But the politician I bribed, well he has a boss, the boss sees him getting something, and wants a cut - now the guy I paid off has 100k, and his boss 100k. Now they want to go buy TV's. But TV's are regulated, and you need to wait 6 months to buy a license. No problem, they'll just slip the regulator at the booth an extra 1000 dollars to let them jump to the front of the line. Then that guys boss wants a cut etc.\n\nSo why do countries have corruption? Because there's no easy way to combat it once it becomes pervasive. No one can be the guy who doesn't take bribes because that's the only way you have enough money to pay all the bribes you need to pay to do anything. \n\nIf you look at the US and europe, corruption is mostly limited to the top. Big companies pay off officials (directly or indirectly) for favourable laws or deals. Congressmen make many times more money working in the private sector than government, so they write laws or behave in a way that sets themselves up for a big payout when they're done. But once you get away from the very top levels of decision making people are mostly paid pretty close to what they are worth (and sometimes too much). \n\nThe problem is that the political optics of paying politicians what they are worth is really hard. If, rather than paying the guy mining the oil/iron/etc. 2 dollars a day you paid him 20, or 200, there wouldn't be any money left to pay bribes with, and his taxes would fund a better government service that would pay people more money etc. But he has no negotiating power to demand that money, because there is an oversupply of labour willing to do his job.\n\nOther things factor into corruption too. Secrecy and illiteracy are tremendously powerful tools. It allows a literate elite to work basically in a separate country within a country, where the vast illiterate (or uninformed) peasant masses have no idea what's really happening, and any gains in the value of their labour can be siphoned off for the informed rich. That's sounds more conspiracy theorist than it really is - most chinese or indian farmers have no idea how the leaders of those countries live, if they don't have TV and can't read they're nearly completely uninformed. But times are changing (in both places), a literate populace, and informed media and you start to see pushback. \n\nThe way you combat corruption is paying people what they are actually worth, transparency (so people know where the money is going and how it's being spent), and giving workers the ability to demand what they are worth. But those only go so far, because in the end, if everyone is corrupt it's just a giant tax evasion scheme, and you need people to want to be honest and to pay taxes, because if they don't want to, they'll work really hard to avoid it. ",
"Another point: Developed countries have high literacy rates so common people are more aware of their rights and less likely to be easily exploited. In developing countries it is not so. \n\nFor example: it will be very difficult for someone to hire people below minimum wage in Europe in Bangladesh not so much."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[]
] |
||
2pa5w9
|
how my flight from melbourne to dubai took 16 hours but my flight from doha to melbourne takes 13?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2pa5w9/eli5_how_my_flight_from_melbourne_to_dubai_took/
|
{
"a_id": [
"cmuqdg0",
"cmuqfd1"
],
"score": [
5,
2
],
"text": [
"I belive it actually has to do with the jet-stream, which is a layer of air that is moving at several hundred miles per hour relative to the surface, but in a more objective sense, this air is not moving (much) with the earth's rotation.\n\nThis makes west-to-east air travel more efficient and faster than east-to-west air travel because of the difference in air resistance from the jet stream.",
"Depending on the high altitude jet streams a plane can fly significantly faster if it follows them. \n\nHappened to me when i took a 6hour flight one way but only 4,5hours back. (It was north- south soo earth rotation was not responsible) \n\nSource: asked a flight attendant"
]
}
|
[] |
[] |
[
[],
[]
] |
||
6y2kvk
|
why does our eye colour gets darker when we're tired?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6y2kvk/eli5_why_does_our_eye_colour_gets_darker_when/
|
{
"a_id": [
"dmk78qd"
],
"score": [
2
],
"text": [
"It doesn't. It's possible for your pupils to dilate (get larger) when you're tired, and that can make your eyes appear darker because your pupils are black and taking up proportionately more space. In general, your pupils dilate more when the light is dimmer (when you're especially sleepy, you might not be opening your eyes all the way, which will make the light effectively dimmer). They can also dilate when you're experiencing strong emotions, like disgust, sexual attraction, or general interest."
]
}
|
[] |
[] |
[
[]
] |
||
xc8tl
|
Are there any sports where women are actually better than men?
|
askscience
|
http://www.reddit.com/r/askscience/comments/xc8tl/are_there_any_sports_where_women_are_actually/
|
{
"a_id": [
"c5l3gep",
"c5l3sst"
],
"score": [
2,
2
],
"text": [
"A few candidates for discussion...\n\nGymnastics\n\nHorse Riding\n\nTaekwondo\n\nNetball",
"It would be helpful if we defined what a \"sport\" is, for the purposes of this conversation. Generally, men have an advantage in height, upper body strength, and lung capacity, so anything that relies on those three things will give a large bias toward men."
]
}
|
[] |
[] |
[
[],
[]
] |
||
8habd5
|
why were spartans especially the warriors considered laconic? and in what ways did this effect their speech/social etiquette?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8habd5/eli5_why_were_spartans_especially_the_warriors/
|
{
"a_id": [
"dyi86x4"
],
"score": [
22
],
"text": [
"Just a quick point of order - The Spartans would have called themselves Lacedaemonians. The word Laconic is from that word. So Spartans talked laconically because speaking laconically meant speaking like someone from Lacedaemonia aka Sparta.\n\nIt was a cultural expectation that Spartan men spoke with as few words as possible, and it lent them a certain blunt and witty reputation. Basically they were really good at one-liners."
]
}
|
[] |
[] |
[
[]
] |
||
27t8dx
|
What is the origin of sleeves?
|
Just wondering, did they originate from one place, or did several cultures invent sleeves independently of one another? I imagine they were necessary in cold climates, so were they a foreign concept to, say, the pre-Columbian tropics?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/27t8dx/what_is_the_origin_of_sleeves/
|
{
"a_id": [
"ci5u72t"
],
"score": [
2
],
"text": [
"The origin of sleeves comes from the first tunics. \n\nThe earliest garments were a single piece of cloth that was wrapped around the body, found in many ancient cultures around the world. Some are still worn today, such as the Indian sari (although it goes over a short tunic-like shirt). Tunics [such as this one](_URL_1_) have been found in Egypt from over 3000 years ago. This tunic consisted of a length of cloth, folded in half, with a slit for the head and the sides sewn closed to create a sleeveless shirt. This was also the poncho worn in what's now South America. \n\nIn The middle east and Europe, the tunic developed sleeves. This was done by either by weaving the cloth narrower for the section that would cover the body or weaving a longer piece of cloth, cutting the end off, and re-attaching it as sleeves. Once the tunic was developed, it stayed largely unchanged for a couple thousand years. It was quite common to see these sleved garments in hotter climates of the Mediterranean and middle east. \n\nSleeves were not associated with cold climates, as the material was often a very light fabric. Pants, however, were only worn by people in northern climates until around the seventeenth century. \n\nI'm not sure if you can say that any one culture invented the tunic, but the earliest surviving examples come from Egypt. Many other cultures also used the single wrapped piece of cloth to create 'sleeves' as part of their wrapped garment. \n\nA good resource on early tunics and wrap clothing is [Cut My Cote, by Dorothy Burnham](_URL_0_)."
]
}
|
[] |
[] |
[
[
"http://www.amazon.ca/Cut-My-Cote-Dorothy-Burnham/dp/0888540469/ref=sr_1_1?ie=UTF8&qid=1402595095&sr=8-1&keywords=cut+my+cote",
"http://www.metmuseum.org/collection/the-collection-online/search/548736?rpp=30&pg=1&ft=tunic&when=2000-1000+B.C.&pos=5"
]
] |
|
404mul
|
how do images get "picked" to be on the front page of a search?
|
Recently noticed how the Nazi flag comes up when searching Comcast.... how does something like this happen?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/404mul/eli5_how_do_images_get_picked_to_be_on_the_front/
|
{
"a_id": [
"cyrg1yk"
],
"score": [
5
],
"text": [
"The exact algorithms that each company uses are closely guarded trade secrets.\n\nTypically they have a program that sifts through the web and tries to find associations between words and images. They also have a way of recognizing images that are very similar to one another (both Google and Microsoft have had winning entries in the annual large-scale image recognition competition in the past two years, so you know that they have a lot of effort that goes into that). The entire field of study is machine learning, and typically the algorithms aren't coded as manually as most computer algorithms—humans set up the basic structure of the algorithm but then the algorithm learns the difficult parts by being exposed to massive amounts of data.\n\nIf an image constantly shows up with a certain word then it's likely that that is the image is related to that word. The one instance of a nazi flag showing up for Comcast that I can see is [this](_URL_0_) Reddit post from /r/circlejerk. Looking at the comments it's pretty obvious how a learning algorithm would think that the image is actually COMCAST. Reddit is a pretty popular site so it winds up ranked pretty highly in the results, especially if the person searching is a redditor (as both you and I are). "
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/circlejerk/comments/2wqfxf/til_that_comcast_was_a_company_created_by_hitler/"
]
] |
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