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1ywm2o | how does a radiation meter work? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ywm2o/eli5_how_does_a_radiation_meter_work/ | {
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"There are different types of radiation detectors\n\n* Geiger tubes: A tube filled with an inert gas at low pressure, when radiation enters the tube it knocks electrons off of the gas and creates a brief pulse of current that can be detected.\n\n* Scintillation counter: Uses a material that releases light upon being struck with radiation. The light is usually detected with a photomultiplier tube, which can detect extremely low levels of light.\n\n* Semiconductor detector: When radiation strikes a semiconductor it produces a brief pulse of current that can be detected."
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bi3fm0 | why does the moon look huge in the distance when poping over a mountain but small on a picture or a video? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bi3fm0/eli5_why_does_the_moon_look_huge_in_the_distance/ | {
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"Forced perspective. When it's next to the mountain, your mind has a frame of reference. In a picture, or even just higher in the sky, you don't have that same reference.",
"The short answer is it's an optical illusion. This is mainly caused by having something to compare the moon's scale too (mountain, building, etc). \n\nMany people belive its due to being lower to the horizon and the atmosphere \"magnifies\" it, however this is incorrect. \n\nTo test this optical illusion for yourself, hold up an object at arms length to the moon when it is low on the horizon and looks larger. Compare the scale of the moon to the object. Then, later when the moon is higher in the sky and looks normal size, hold the same object at arms length again. You will see its the same size.",
"In addition to the other answers, in photography and film, you can use certain lenses and techniques to make the moon look gigantic, while the camera on phones and a lot of other things generally do the opposite. It might look smaller in the picture than it does irl because the camera being used creates the illusion that it is smaller than it really is",
"It's a well known optical illusion called the Moon Illusion. It's even apparent in video games like Minecraft. The closer to the horizon the moon is the bigger it looks.",
"The most likely reason for this illusion is how your brain's vision handling system interpets the Moon's distance. Your brain handles the Moon as being 'in the sky', and the sky is where the clouds are.\n\nWhen you are looking near the horizon, the clouds, and that horizon, are a long way away. So our brains assume the Moon is about that same distance away, so they present the Moon to us as very large object among distant things.\n\nWhen you are looking straight up, those same clouds are fairly close. Even when there are no clouds, our brains assume that the sky above us is a flat layer. So we see the moon as a small object that is close.\n\nThis image handling happens on a subconscious level, and the results are passed to our conscious mind. Only then do apply our knowledge that the moon is the same object that is very distant, and that its apparent changing size is not logical. In fact, because the Moon is further away from us when it rises, it should appear slightly smaller at the horizon than when it is overhead - and if you measure it - which is what a camera does - that is what you would find.",
"Not sure why everyone is explaining why the moon looks bigger near the horizon compared to up in the sky when the question is specifically about comparing it to a photo or video. \n\nThe answer is when you take a photo on your phone, your phone has a wide angle lens which tries to get a wide field of view. I.e it tries to capture the entire scenery in front of you. Distant objects look smaller the wider your lens is. \n\nTo get around this problem you need to use a telephoto lens. Telephoto (zoom) lenses make distant objects appear bigger because they have a narrower field of view. \n\nTo make the moon still appear bigger you could include a distant object in the picture like a building or an airplane. \n\nThe relative size of the distant object to the moon will make the moon look huge.\n\nEdit: edited for clarity",
"Moon Illusion.\n\n_URL_0_\n\nI know it is a WikiLink, but still a good read.",
" > but small on a picture or a video?\n\nThe size the moon appears in a picture or video is dictated by the focal length of the lens you are using, wide angle lenses make the moon appear small in a photograph and telephoto lenses make it appear larger. It would be similar in comparison to looking at the moon through binoculars versus looking at the moon through a telescope. \n\nAs an example phone cameras generally use the equivalent of 35mm or 50mm lenses (compared to 35mm SLR lenses), this is a relatively wide angle lenses so the moon appears very small in the picture. If you use a telephoto lens such as a 200mm, 500mm, or 800mm lens the moon will appear much larger in the photograph. The longer the focal length of the lens the more the moon will be magnified in the picture.",
"Focal length makes the background small in a lot of cellphone-type shots. To make the moon big, your best bet is to shoot it with a telescope. To get it big in the background, you would use a 400mm+ lens to shoot an object with the moon in the background.\n\nThe focal length keeps the subject normal but zooms the background a lot.",
"It has to do with the lens of the camera. If you shoot the moon with a lens upwards of 85mm it would look like it should, with a proper scale compared to other objects in the picture.\n\nWide lenses (35mm and wider) make things look further away and smaller. And phones rarely have a lens that is longer than 24-28mm.",
"I thought it had to do with focal length but now everyone in this thread says its because we dont know. Good?",
"It is not an optical illusion. It is not a perspective issue either. It is how light hits the camera sensor after bending through a curved lens. This is essentially how lenses are supposed to work.\n\nYou curve the lens to gather light from a wider area. As a consequence, the objects are rendered smaller. If you have one of those small curved rear view mirrors that stick on your existing rear view mirrors in the car, you know what I am talking about. These show you objects, but they don’t give you a good idea of their distance.\n\nOn a wide angle lens like your cellphone, objects at a distance appear smaller. That’s why your subject looks normal but the buildings or the horizon look smaller and get cramped into the scene.\n\nNow compare the distance between your subject and those buildings to the distance between the subject and the moon!",
"It all comes down to the focal length of the lens being used to catch the image. The longer the focal length, the more gigantic distant things are going to look. You can do tricks with this by having distant objects between you and the moon also showcased. So if you're miles away from a city skyline with the moon rising over it and you use say a 400mm lens to capture the image it's going to make the moon look like it takes up a meaningful percentage of the sky.\n\nHere's a good explainer. Photog used a 500mm max zoom dialed to the end with 2 teleconverters connected for an effective focal length of 1000mm or thereabouts.\n\n[_URL_0_](_URL_0_)",
"In my experience, whenever you poop over a mountain you have a strain a bit because your butthole gets real nervous. That makes your vision go blurry, so the moon appears bigger.",
"Are my eyes broken? Moon always looks small"
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33hanm | difference between a think tank and a lobbyist | Hi people, I'm not from USA and not familiarized with the term "Think Tank", for what I've read TT are companies do research and try to influence politicians and society in general, but isn't this the same thing that lobbyist do? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/33hanm/eli5_difference_between_a_think_tank_and_a/ | {
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"Lobbyists generally work on the behalf of a specific entity, be it a company or some other interest group. Basically, you tell them what your goals are, and they'll go argue for you for a fee. \n\nThink tanks tend to be more dedicated towards a specific ideology or cause, rather than just lobbying for the desires of whoever pays them. \n\nBut I think it's fair to say that the line between them can be rather blurry at times. ",
"I work for a non-profit, non-partisan think tank so I wanted to weigh in here.\n\nThe fundamental difference between a think thank and a lobbying firm is that think tanks research policies (without necessarily endorsing them) and lobbying firms argue for policies.\n\nUnlike lobbyists, who are hired by specific entities (usually large companies) to persuade people (typically politicians) into adopting (or not adopting) certain policies, think thank researchers are not wedded to any specific policy or entity. \n\nIn principle, think tanks conduct independent research on what the policy options are. Again, in principle, they exist to defend the public interest as they see it. Think tanks don't want X policy or Y policy (or right-wing or left-wing), they want the BEST policy.\n\nIn practice, it is a little more muddied than that. Think tanks always get their funding from somewhere/someone. A lot of \"think tanks\" lose their independence (if they had any to begin with) when they start to rely on one or a few large donors. As one example, this article recently condemned a lot of high profile think tanks for taking substantial amounts of foreign money in exchange for tailoring their research agendas to favor the donor nations: _URL_0_\n\nSimilarly, there are many think tanks out there (I won't name them, since I'd rather not have to create a new account) that are merely fronts for industry or political interests, so their \"research\" is highly suspect. \n\nThis problem ultimately manifests in a situation where people are not only entitled to their own opinions, but increasingly to their own \"facts\". \n\nThe way to tell a genuine think tank from a compromised one is to look at their funding sources (any respectable organization will make this information easily available) and make sure that there are a wide variety of sources, ideally some government, some industry (and not all from the same industry), and a lot of funding from respectable charitable foundations like Ford Foundation, Open Society Foundation, Knight Foundation, etc."
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3tlebc | why doesn't the government build hospital's with the medicare budget instead of acting as insurance? | The Medicaid and Medicare budgets are massive so why not simply build hospitals instead of insurance for people? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3tlebc/eli5_why_doesnt_the_government_build_hospitals/ | {
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"Because the issue being addressed isn't \"there are not enough hospitals\".\n\nThere are *plenty* of hospitals in the US. The issue is that not everyone can afford medical care. Medicare/Medicaid are intended to help remedy that issue.",
"There are plenty of hospitals, and in most areas there is no reason to build new ones. The problem is paying for medical care. The doctors and nurses will still need to be paid, the equipment still needs to be maintained, the janitors and technicians still need to be paid, the supplies still need to be bought.\n\nWith all those expenses, you are back to people needing Medicare to pay for their medical bills."
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4uot0t | why do carbonated drinks hurt us when we drink too fast? | It's just bubbles, right? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4uot0t/eli5_why_do_carbonated_drinks_hurt_us_when_we/ | {
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"The bubbles are composed of carbon dioxide, which can taste \"spicy\"...here's an article with more information _URL_0_",
"Carbonated drinks contain dissolved carbon dioxide. Carbon dioxide naturally reacts with water (in the drink) to produce carbonic acid (a weak acid). Weak acids such as citric acid (lemon juice) or acetic acid (vinegar) have a sour taste, so carbonating drinks changes their taste along with giving them an interesting texture. \n\nIf you guzzle down a soda the carbon dioxide bubbles collect in your stomach and eventually you burp up almost pure carbon dioxide. If you happen to exhale the burp through your nose then the carbon dioxide can react with the water on the surface of your nasal passage to form carbonic acid. Your nose is sensitive to things like acids to protect you from breathing in nasty things, so having an acid suddenly form on the inside of your nose sets off pain receptors and gives you an eye watering sensation."
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7h2bdl | Why did people pay money to buy officers commissions in the army? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/7h2bdl/why_did_people_pay_money_to_buy_officers/ | {
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"Just to clarify, are you asking why an army would allow people purchase commissions, or why someone would bother paying money for an officer's commission?",
"While previous questions don't address the precise points you are asking here is a previous archived question with answers including a link to a detailed study of the benefits both to the individual Officer and to the Crown of the British system\n\n_URL_1_\n\nand another, similar question, here\n\n_URL_0_\n"
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cvkh5w | how have actions such as the head nod and head shake become universally understood in contrast to languages. | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cvkh5w/eli5_how_have_actions_such_as_the_head_nod_and/ | {
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"They haven't really. Lots of places won't know what you mean if you shake your head. In India they do a side to side wobble instead of nodding. Stuff like hand signals can mean completely different things in different places, like the OK sign is seriously rude in Thailand.",
"They're not actually universal. I've heard that countries like Bulgaria and Macedonia use the opposite signals. Same with giving people a thumbs up. It's an insult in Italy and Iran(?).",
"A thumbs up or or offering a left hand to shake is serioualy offensive in parts of the middle east (the thunbs up amounts to \"up yours\" and the left hand is considered unclean).\n\nIn places nodding up and down is a sign of confusion.\n\nIn others not meeting your eyes or looking you in the face is a sigb of respect, whereas in the US, etc it's viewed as a bad sign.",
"In disney Parks, mascot characters will point directionally with both their index and middle fingers together as pointing with just your index is considered rude in some cultures."
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1fqeoi | What was the vikings' knowledge of contemporary mathematics? (What kind of number system did they use, etc?) | Coming from Norway I have always learned a great bit about vikings and their endeavors: Their culture and craftsmanship is always mentioned in the same breath as their ship building skills. And, of course, their — ehm — "sightseeing" and other exploits in England are covered. However, something I've been curious about but never covered at all is their use of maths and physics (possibly in their crafts), and I can't find all that much on the topic of "viking maths". Did they have any knowledge of more advanced mathematics than counting? I've heard they had a word for something around one hundred.
What was their knowledge of geometry, numbers and so on? Which number system did they use? What kind of notation? Did they use positional notation? Arithmetic operations? What was their view on numbers and/or quantity? Did they have an idea of zero? Were they familiar with what we today call the Pythagorean theorem?
Did they have any knowledge of a more formal way to think about water displacement than "water gets bigger when we put stuff in it"?
I don't know if these are too broad or otherwise unanswerable, but I am going to take a shot regardless; I can't get *less* information than I currently have on the topic anyway. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1fqeoi/what_was_the_vikings_knowledge_of_contemporary/ | {
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"I can't speak to much of this, but I doubt they had a concept of zero. If we're talking about the Viking Age here, that's centuries before Fibonacci and the introduction of Hindu mathematics. Vikings *were* sea traders, but sea traders in Europe were fairly mathematically illiterate before Fibonacci and *Di Minor Guisa*, his simplified educational text intended for merchants and such.\n\nThere were some English monks who wrote some texts, mostly of word problems not too far off from the Hindu-Arabic sort, but that's about as close as you could get, I think.\n\nI can dig up my old History of Math book, if you'd like.",
"Looking at some cutouts and designs of ships, I see that they implemented alot of mathematical concepts in their engineering. They use [catenerial](_URL_1_) concavities for their [longship hulls](_URL_0_) and employed rudimentary geometry in their rigging, as seen by the symmetries in the forward and aft lines. They had at least some idea of hydrodynamics, as evidenced by their production and usage of a hydrofoil on the Godstak ship, this used to offset the drag created by the steerboard. Of course all of this is inductive thinking and as such it should be taken with a grain of salt. It is very possible that those members of the Viking Age arrived at these constructs through a process of trial and error, rather than a solid implementation of scientific pursuit.",
"This is a bit of a problematic question, because these theoretical issues are not typically captured in writing of the time period (which is more concerned with narratives and events). We only have the material evidence to go on (the archaeology), and for that it is hard to determine, as noted, what is derived from 'trial and error' (or what I would call craftsman's experience), and what from deliberate theoretical planning. As Norse shipbuilding is very traditional (designs hardly change over centuries, there is very little experimenting), I suspect tradition is the primary source of technologically advanced designs, rather than deep theoretical insight. And yes, this includes the incorporation of things like geometry and hydrofoils.\n\nThis changes at the rule of Harald Bluetooth, Denmark in the 970s. Particularly the Trelleborg fortresses seem to have been built according to a fixed plan, rather than the ad-hoc forts that are common before that time. It even incorporates a standard length measure (120 meters and variations of it), which also recurs in both aristocratic land measures and, particularly, the monument at Jelling. Numbers (particularly fractures, such as fifths) here play a very important role in the setup of the complex, but the whole 'breaking of tradition' aspect of Harald's monumentality to me is even more evidence that such systematic application of number systems was not in place before that time.\n\nThere are some standard weights found at the marketplace at Hedeby, though, but these point to little more than 'counting', and are not evidence of a mathematical system.\n\nFinally, I could refer you to [this website](_URL_0_); the Viking Answer Lady here provides an excellent overview of numbers on runestones and inscriptions (I am not aware of any such overview from scientific literature)."
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5e8wyi | why do human babies take years to raise while other animals like puppies or antelopes take only a few months? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5e8wyi/eli5_why_do_human_babies_take_years_to_raise/ | {
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"Partially because of life-expectancy - a human lives 75 years, whereas a dogs life-expectancy is more like 10 years.\n\nAlso, humans traded instinct for a more advanced brain. Animals instinctually know how to do a lot more than we do, but our learning curve beats everything else."
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bpc1h1 | home buying terms | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bpc1h1/eli5_home_buying_terms/ | {
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" > What are points and origination fees?\n\nThe origination fee is like an upfront payment to the lender for creating the loan. It is usually a percentage (0.5%, 1%) of the loan amount. _URL_1_\n\n > Is earnest money basically just a deposit? Does it get factored into the sale at all?\n\nThis is also called \"good faith\" money. It is like a deposit - it shows that you and the seller have taken the first step to put the house under contract, that you intend to buy the house (pending any serious findings from an inspection), etc. If you go through with the sale, then that money will go towards the final cost of the house, like part of an early deposit. If you as a buyer do not go through with the purchase because the inspection found a ton of mold or meth damage that wasn't previously disclosed (or other previously non-disclosed issues) then you should be entitled to the money back. If you do not go through with the purchase because you got cold feet/changed your mind, then you would not get the money back. If the seller changes his/her mind then you would get the money back.\n\n > What is a short sell and why do lenders ask if a house is a short sell?\n\nA short *sale* usually happens when the seller is having financial problems and the house is about to be foreclosed. They are trying to sell the house for less money than what their current loan amount for it is (for instance, they might owe $200,000 still but are trying to sell it for $160,000). Or it could be when the property of the value has fallen lower than what the owner owes and the loan holder might recover *some* money from the sale of the house in its current state. \n\nIt just requires more paperwork and more agreements on everyone's part to get a short sale through, since the bank that owns the title on the house has to agree to sell it at a loss basically. \n\nI would also caution you about short sales and just advise you to assume the worst possible scenario, which is that the person couldn't make financial payments, which means they probably couldn't pay to keep the house up so there might be some serious problems that you'll want to check for during an inspection (and some problems might even be self-evident when you do the initial walkthrough).\n\n > Is the interest rate different than the APR? If so, how are they different? If not, why are both terms used interchangeably?\n\nAPR = annual percentage rate, it is the more technical term for \"interest rate\". They're used interchangeably because they're equally common terms for the same thing. Sort of like how someone might say \"soda\" and someone might say \"pop\", or \"gas\" and \"fuel\". \n\n > What is mortgage insurance and what is covered by it?\n\nAlso called \"Private Mortgage Insurance\" or \"PMI\". It's generally activated when a buyer does not put down at least 20% deposit off the purchase cost. It's basically a way to protect the lender and help ensure the lender's investment in you is covered in case you stop paying the mortgage / fall behind on your payments. Some loans require it by default, others don't. You can read more about it here: _URL_0_\n\n > What happens in the time between going under contract and when you close?\n\nIf the loan isn't secured yet (ie, you were pre-approved so you could make the offer but the loan wasn't fully processed), they would fully process it. You would have licensed home inspectors come and check everything for issues (make sure the outlets work, make sure the appliances work, make sure the air conditioning and heat work, check for structural damage, make sure there aren't any gas leaks or unmitigated radon risks, stuff like that); once these inspections are done you get a report of the issues, and you can even go negotiate with the seller to get some of them fixed as part of a bargaining tool. You'll get homeowner's insurance set up. You can pay to get the title of the property inspected and secured so you don't have someone trying to make a claim against you ten years down the road that the property is part of their great-great-great-grandfather's inheritance that they just received. Stuff like that. \n\n**Since it's your first time buying a house, do research online about what benefits your state might offer you**. In some states there are first time home buyer benefits you can get access to that can help alleviate a little bit of the cost or grant you access to certain loans with better benefits.\n\nedit: If you live in Maryland I know a great guy > _ > I don't want to advertise here, PM me but this agent hooked me up with one of the hardest working lenders and insurance agents I'll probably ever meet."
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ee6chc | What causes flesh to rot? | Is the cause internal, external, a chemical reaction? | askscience | https://www.reddit.com/r/askscience/comments/ee6chc/what_causes_flesh_to_rot/ | {
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"Cells die and dry out, releasing gases that attract insects and bacteria as well as other scavengers to break down the flesh. This is a very basic explanation and I’m sure someone else can do a better job of it.",
"Microbes.\n\nWithout them you'd just dry out into leather.\n\nThis is why preservation works.\n\nBasically things will eat you unless you can defend and rebuild yourself.\n\nThe causes could also be internal. Like perforated bowel or infection.\n\nThen you got tooth rot, primarily that's the bacteria strep. mutans. The same one that causes strep throat.\n\nWithout microbes nothing would rot and decay as we know it."
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1qza1a | Celtic Warfare | Hi there. I am a historian student and I'd like to write my bachelorpaper on Celtic Warfare. Not against Romans but among other Celtic Tribes. I wonder if some of you know some sources from this topic? Your help is greatly appreciated :) | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1qza1a/celtic_warfare/ | {
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"Does your assignment require you to use primary written sources? \n\nOur knowledge of the Celts comes mainly from Greek and Roman writers, from myth and legends ostensibly based on oral traditions and from archaeological evidence. \n\nIf you are permitted to rely heavily on using secondary and tertiary written sources and archaeology you should be okay, but if your assignment marking scheme is focused on your use of primary sources I would not tackle this at this juncture. It feels to me like a post-grad topic rather than an undergrad topic. \n\nHaving said that - if you have the freedom to tackle things from an indirect angle you can sink your teeth in to understanding how historians have interpreted the opaque Celtic world through indirect evidence. I would start by asking for pointers on evidence of battle scenes and warfare over at r/archaeology. A big picture approach runs the risk of getting you bogged down so I'd try to either narrow down to a particular region and period or to look at the development and spread of a particular weapon or tactic. \n",
"The problem with writing about Gallic or Brythonic warfare is that unless you base it solely on archaeology, you're going to have to use Roman/Greek sources, and if you don't, your secondary sources are going to be based off of them anyway. Celtic speakers never wrote much about themselves until the early medieval era so your literary sources will be almost non-existent. I don't think there's much harm in using sources like Polybius and Caesar and then extrapolating their descriptions of Gallic or Brythonic warfare to how these people fought amongst themselves.\n\nThis excerpt from Polybius' [*Histories*](_URL_1_) is a wonderful description of a battle between Gauls and Romans, especially its capture of Gallic pre-battle intimidation tactics. Blowing loads of horns and shouting war-cries before a charge seems to have been a fixture of Celtic warfare and was continued up until the end of the medieval era in Ireland. \n\nCaesar's *Commentaries* are another great source because it's actually a first hand account of his wars in Gaul and Britain. It deals with more strategic issues but also has good narrative descriptions of things like Gallic fortifications and the use of chariots in Britain.\n\nYou'll want to look into the Halstatt and later La Tene military aristocracies who were at the core of Gallic society to fully understand Gallic, Brytonic or Goedelic warfare. Your sources for this will mostly be archaeological, and [*Celtic Chiefdom, Celtic State*](_URL_0_) has a pretty good rundown on the origins of the warrior aristocracy and its motivations."
]
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| []
| [
[],
[
"http://www.amazon.com/Celtic-Chiefdom-State-Prehistoric-Archaeology/dp/0521585791",
"http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Polybius/2*.html#28.3"
]
]
|
|
12k1it | Is is possible to regrow half of your liver? | askscience | http://www.reddit.com/r/askscience/comments/12k1it/is_is_possible_to_regrow_half_of_your_liver/ | {
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"_URL_1_\n\nShorter answer: yes.\n\n[Oh hey, the wikipedia article 'liver'](_URL_0_) says it grow from as little as 25%, though not in the original shape, but expansion from what's left to the same size and function as the original."
]
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[
"https://en.wikipedia.org/wiki/Liver#Regeneration",
"http://lmgtfy.com/?q=can+the+liver+grow+back"
]
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|
||
35efvf | why do newtonian physics break down at a quantum level? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/35efvf/eli5why_do_newtonian_physics_break_down_at_a/ | {
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"Because, Newtonian Mechanics, Quantum Mechanics and other mechanics are simply a model of reality.\n\nIn each case, the model is the simplest explanation (Occam's razor) which could explain and predict all the phenomena observed. When Newton created the Newtonian Mechanics, the existance of Quantum level mechanics wasn't known, so the model never attempted to predict behaviour there.",
"It's not so much that they break down, rather it's that Newtonian physics is an approximation of how the world works that is not totally correct, but in many cases is accurate enough to be incredibly useful. In such circumstances (like the ordinary motion of a baseball), the inaccuracy is so low as to be practically imperceptible, though it is still there. When things become very small, very large, or very fast, however, the Newtonian model is very inaccurate.",
"A lot of people here, I feel, aren't really answering your question as to **why** it breaks down. The easiest way to explain this is with examples. One of the initial ways we discovered quantum mechanics is through exploration of the atom. Initially, we formulated the idea of an atom that was rigid, a building block for molecules, that was built off of newtonian forces. As we discovered more and more about the atom, this explanation became increasingly less consistent with the actual data. For example, we discovered that atoms weren't solid objects, but actually mostly empty space, held together by forces that weren't described in newtonian physics (the strong and weak forces). From there, we discovered principles that led much of the structure of the atom to be based on probability (the probability that an electron was in a certain location) rather than rigid orbits, which would have been more consistent (although still not that consistent) with Newtonian mechanics.\n\nSome other examples include the duality of particles (their ability to be both particles and waves) and quantum tunneling (this duality allows some low-mass particles to pass through solid objects!). The current standard model has all forces mediated by particles, which would have never been even dreamed of by Newton.\n\nRelativity does the same, but breaks down ideas mainly about motion and frame of reference (or in the case of GR, gravity).",
"Theories break down when the postulates behind them are no longer valid. For example, Newton's laws postulate objects at rest stay at rest unless acted upon. At a quantum level, we know this isn't true, because particles are really just smeared out probability distributions telling us we could find the particle in lots of places. This is telling us that firstly the idea of a solid particle is not really accurate at the quantum level, and the idea of something being stationary isn't really applicable too! Newtonian mechanics doesn't take this into account, so when the affects of it become noticeable, it ruins the results of the theory. If we look at the non-quantum limit of systems with quantum mechanics though, we can see Newton's laws emerge as a kind of average behaviour, which is why they work at big scales.\n\nThe same thing happens when you go from quantum mechanics (which is a low energy theory) to quantum field theory (high energy). Quantum mechanics postulate a conserved number of particles (to keep wavefunctions normalised or something, I can't really remember), but that clearly isn't very physical because we know particles can be created and destroyed in real life. Quantum field theory can accommodate both all of quantum mechanics and the extra stuff that comes from moving close to the speed of light, like particle production and relativistic effects. If we take a low energy limit of QFT, we get quantum mechanics back!\n\nThe standard model itself is what's called an \"Effective Field Theory\", because it's only valid up to a certain scale. On very high energies, we know it isn't right because it doesn't know about quantum gravity, so we know it isn't going to give us the right answers.\n\nTL;DR\nTheories (like Newton's) work because the things they don't know about don't really make a difference compared to the things they do (like quantum mechanics or relativity). When the things they don't know about start to cause a big effect, they still don't know about it so give wrong answers. \n\nIt's like if you try to drive a car without knowing about the steering wheel. It's fine if you're moving on a straight road, because you don't need to know about it. But when you meet a corner, you can't do a good job."
]
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2uka8z | Could an "electromagnetic black hole" exist? | My understanding of the fundamental forces of the universe is that gravity is extremely weak compared to the other forces, such as electromagnetism. Still, gravity has profound effects in the universe, and it seems like the most extreme example is a black hole. For the purposes of this question, this is a "gravitational black hole." Could a black hole formed by electromagnetism exist? | askscience | http://www.reddit.com/r/askscience/comments/2uka8z/could_an_electromagnetic_black_hole_exist/ | {
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"The answer is no. There are a couple of features of gravity that make it unique and the only candidate force to produce black hole-like phenomena.\n\n1. Gravity interacts with everything on the same way (it's very democratic). And everything is everything, including itself. This is an important ingredient because as soon as some particle was blind to gravity then it could scape from the black hole as it wouldn't even notice there was one.\n\n2. And it's always attractive. Which is important in order to form a black-hole in the first place.\n\nIn the case of the electromagnetic force same charges repel (positive repels positive and viceversa) and opposites attract. What this means in practice is that it is very hard to create configurations with a large amount of charge as they would start to repel each other and will start attracting more strongly opposite charges that would try to neutralize it. An example of this are the atoms, which have a positively charged nucleus (held together by nuclear forces) and then as many electrons as necessary to make it neutral. In fact, this qualitative property affects every Spin 1 theory which covers electromagnetism, weak and strong nuclear forces.\n\nA theorist might wonder, what could happen if existed some unknown force mediated by a Spin 0 massless particle? Could it create a black hole? Well, this theory has the property that it doesn't repel same charges as electromagnetism. So that's good. But it doesn't attract light! In fact, this theory is some sort of relativity Newtonian gravity. And has been ruled out as incorrect through observation, it also predicts the wrong Mercurian perihelium precession.\n\nSo we have ruled out... Spin 0 (as it doesn't attract light), Spin 1 (as same charges repel and also doesn't attract neutral particles). Next step would be a Spin 2 massless theory but that is essentially General Relativity. And it turns out there can't be interacting theories of massless higher spin fields for some technical reasons regarding conserved charges and symmetries."
]
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dzdlb2 | What if you took some simple scuba gear, maybe a weight, and applied a hydrophobic layer? | Let's say you put in ear plugs, wore goggles that covered the nose, a diving cap to hold your hair down, took a tank of air, and then sprayed everything in a hydrophobic layer. Would this allow you to go deeper into a body of water than if you just did this without the hydrophobic layer? The earplugs is obviously to counteract the pressure on the ear, goggles for the eyes and nose, where as the rest of the body seems to handle higher water pressures better than these areas, and the cap just to make the hydrophobic layer easier to create.
Besides obviously not getting wet, with the weight of the tank, how far down could you walk on the ocean floor beyond the normal? Would this even have an effect? Would you need to bring more weights or would the layer allow you to just slip down? Or does this only seem like a cool idea in my head? | askscience | https://www.reddit.com/r/askscience/comments/dzdlb2/what_if_you_took_some_simple_scuba_gear_maybe_a/ | {
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"What stops you from sinking is not friction, but buoyancy. The water pressure supports you with a force equal to the weight of the water you displaced. Having a layer of hydrophobic material doesn't really change this - it's no different to having a layer of clothing or whatever, it's just another surface that the water pressure propagates through. If anything, it may make it slightly *harder* to sink, because the hydrophobic material will repulse the water a little, and increase the volume of water you displace.\n\nThe big thing is the weight. Humans are pretty close to neutrally buoyant, which is why can float without much effort, but also dive under the water without being immediately forced to the top. But if you've got a weight belt or whatever, you can easily get much heavier than the water around you, and sink. The more weight you have, the faster you'll sink.",
"Are you asking how much less wet would you be with the weight of the water still affecting you the same exact way? \nUnless you create a pressurized container, like a submarine, you really only have a certain limit of depth before the pressure of the water would start to crush you or cause problems like bubbles in your blood. Wearing goggles wouldn’t stop the pressure of the water from popping your eyes out if you go too deep. You definitely need weights to dive down deep, or else you’ll be swimming for a while. Wetsuits increase your buoyancy, so if you go without a wetsuit I guess you could ditch some weight that way. Basically, you can go down as deep as you can until you pass out from the forces. Coating yourself in a hydrophobic layer wouldn’t negate the pressure of a column of water. Bubbles would, though. A lot of them.",
"The difficulty with deep diving is the pressure. The human body hasn't evolved to work in extremely high pressures and various problems start happening. Some can be mitigated by breathing special gas mixtures rather than normal compressed air. A hydrophobic coating is not going to prevent you being subject to the water pressure.\n\nThe highest air pressure humans have been shown to tolerate (in hyperbaric chamber) is equivalent to a depth of 700 metres, and the deepest actual dive when subject to the pressure of the water is 534 metres. This dive was done using the technique of *saturation diving*. The divers live for days or weeks in a high-pressure environment, usually a hyperbaric chamber on a support ship. When they actually do a dive they are lowered to depth in a pressurised diving bell, before connecting to a gas supply from the surface and exiting in the water. In this way the divers are \"pressurised\" once and then decompressed once, which is less harmful than being subjected to repeated or rapid changes of pressure.\n\nThe record for SCUBA is 332 metres and deep SCUBA diving is considered much more dangerous, because the diver must carry all their gas mixtures with them requiring different gases for different depths and the dive is time limited by the available gas supply.",
"1) It would make no difference at all. What stops people diving deep is the water pressure. None of this will have any effect on the pressure. It would be the equivalent of using a drysuit, and a drysuit doesn't change the depth that you can dive to.\n\n2) DO NOT USE EARPLUGS WHEN DIVING! The pressure at depth will ram then deeper and deeper into your ears, then when you come up there will be a pocket of high-pressure air behind the plug which is actually more likely to burst your eardrums than it is to push out the earplugs. It would be incredibly painful, and that close to your brain, life threatening. You do not want an expanding air pocket in your head."
]
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qeuc7 | why the vitamins are named like they are. why do we have 12 vitamin b's but no vitamin j? is there a vitamin b9? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/qeuc7/eli5_why_the_vitamins_are_named_like_they_are_why/ | {
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"[Copy-paste from here:](_URL_0_)\nWhen they[Vitamins] were discovered they were given temporary names, starting with Vitamin A, then B, C, D and so on. Then we discovered that Vitamin B was a mixture of several different chemicals so they were given subscript numbers 1 to 12. We knew what they did, but did not know their chemical composition. Even though we now know their chemical names, we still use their temporary names. (I don't know why we jumped from E to K.)",
"There used to be more vitamin letters, but we later learned that these weren't right, or were the same as others. So, we stopped calling them by things like vitamin J. \n\nAll of the vitamin B vitamins were once thought to be a single vitamin. When we learned more about them and their different sources, we broken them down into sub-vitamins. "
]
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| []
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"http://www.purchon.com/biology/vitamins.htm"
],
[]
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||
5u7ooe | How should we remember Captain James Cook? | I came across an controversial Facebook post regarding his death and decided to do some research. Was he a ruthless colonialist or a brilliant navigator? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/5u7ooe/how_should_we_remember_captain_james_cook/ | {
"a_id": [
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"text": [
"Really there's nothing stopping him from being both. He did have significant navigation/cartographical skills, sailing thousands of miles that he had no maps for. \n\nThat said he was an English sailor under the British Navy at the start of British imperialism. His voyages were basically commissioned to see if Australia existed and to see if there was an opportunity for new outposts for the Empire. He named landings and places he surveyed and we continue to use those over the Indigenous names. \n\nAlso he did try to kidnap a Hawaiian chief, which got him killed. So not the best guy. "
]
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| [
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9mw9q0 | why can’t you hum while holding your nose? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9mw9q0/eli5_why_cant_you_hum_while_holding_your_nose/ | {
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"You can if you open your mouth. The air that carries the sound from your vocal cords has to go somewhere. ",
"Because humming is essentially forcing sound to come out of your nose. You're basically pronouncing a nasal consonant; so if you're blocking your nose, you can't pronounce a nasal consonant, and thus, cannot hum. "
]
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b45rb3 | Is it possible to navigate without GPS and satellites using the earth's geomagnetic field instead (like birds do)? | I was reading about birds sense of Biomagnetism and was wondering myself if there was a way to use earth's magnetic field to navigate and determine latitude or even longitude. Now, I've heard about Compasses, but it's a little dated technology. Are there sensors around that can measure the geomagnetic field more accurately, making something like a satellite independent navigation system possible? | askscience | https://www.reddit.com/r/askscience/comments/b45rb3/is_it_possible_to_navigate_without_gps_and/ | {
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" > Now, I've heard about Compasses\n\nYou are probably thinking of regular old cheap compasses. But there are high accuracy electronic compasses which is what you appear to be talking about. [Like this one.](_URL_0_)",
"No matter how accurately you measure the magnetic field of the earth, that's still all the information you have: magnetic field. This can only be used to tell relative directions. Even if you knew how the field strength and direction varied all over the Earth's surface, you could only narrow your position down to an isomagnetic line, not a unique point. If you had no idea what your latitude and longitude were at your starting point, you couldn't determine it. If you knew your starting point a sufficiently accurate compass would allow you to know your position as you move, as long as you keep track of your heading and distance travelled. Map and compass navigation can be very accurate.",
"While you can't navigate entirely with a compass (well, sort of you can. You can do something called 'dead reckoning' where you determine which direction you need to move in to get where you're going and then you always move in that direction. The problem is, if you get off, you have no way of knowing). \n\nBut there is GPS independent navigation. Interestingly, knowing your latitude is easy. Even back in the days of Newton they could tell their latitude using nothing but a [sextant](_URL_0_). There, you just measure the angle between the horizon and the North Star and you can extract your latitude. \n\nLongitude is harder, since the lines of longitude move through space with the Earth's rotation. To know what longitude you're looking at, you need to know what time you're looking at different stars. Which, is easy for us today, even a cheap quartz watch is accurate enough to tell you time sailing across the ocean, but long ago, it was much harder to know what time it was. They had worked out the mathematics long before they had worked out the time keeping. "
]
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| []
| [
[
"http://www.electronics123.com/shop/product/srs-220-high-accuracy-digital-compass-with-4-20ma-output-24v-dc-powered-9032?search=power&category=390"
],
[],
[
"https://en.wikipedia.org/wiki/Sextant"
]
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|
|
555gaf | why do separate drops of cooking oil tend to drift towards each other when on water? | explanetti my spaghetti | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/555gaf/eli5why_do_separate_drops_of_cooking_oil_tend_to/ | {
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"score": [
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"text": [
"Gravity. Water is polar so it forms a strong surface tension, the oil is less dense so it sits on top. Gravity makes the oil naturally tend to \"puddle\" on top of the water."
]
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| [
[]
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|
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1id1mz | How much gasoline is actually wasted at a stop sign? | I am curious to know how much extra pollution is created by adding stop signs to a road. There's a 3-way intersection on my street that never had a stop sign, but some woman down the road recently complained to the city about the speed of drivers, and they erected a 3 way stop.
I'm wondering just how much extra pollution has resulted, and how much gasoline has been wasted by motorists. So, what's the result of a single car stopping at a stop sign? | askscience | http://www.reddit.com/r/askscience/comments/1id1mz/how_much_gasoline_is_actually_wasted_at_a_stop/ | {
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"well fuel is burned very slowly\n\nI get 33 mpg at 60mph chilling at 3000 RPM in my 4 cylinder 1.9 liter Mazda.\n\nI'd say that I burn 1/33 of a gallon of gas a Minute because I'd have to go 33 miles to use a gallon, right?\n\nSo, idling at a stop sign my car spins at 700 RPM, which is about one quarter of the explosions needed to keep it at 3000 RPM so you could say I burn 1/33/4 gallons of gas a minute at a stop sign. \n\nthat's .0075 gallons per minute. I don't know about you but I'm only actually stopped at a stop sign for a few seconds if that.\n\nI'd say the better question is how much more fuel is consumed in the slowing down stopping and accelerating process vs just maintaining speed over the distance in question",
"0.00314248 gallons, or 0.0118956 L.\n\nAssumes: car must accelerate to 25 mph after stopping. Car weighs 2000 kg. Efficiency of engine is 30%. Gasoline energy density is 35 MJ/L. No other energy losses during acceleration (e.g. no friction).\n\nMy work in Mathematica: _URL_0_"
]
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[],
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"https://gist.github.com/anonymous/6005155"
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4c8q75 | could a nuclear submarine survive in space? if so, for how long? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4c8q75/eli5_could_a_nuclear_submarine_survive_in_space/ | {
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"text": [
"It is strong in compression, in tension it's less clear."
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dmro2y | Rhodesia | I've heard about Rhodesia recently and have found an article by the new York times about White supremacists linked to it, I had always had the impression the fight was about communism, and avoiding a shift of power that led to Dictatorships and totalitarian regimes, can anyone sort this out? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/dmro2y/rhodesia/ | {
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"You might find interesting the following previous answers:\n\n* [Why does the story of Rhodesia attract so many racists?](_URL_2_) answered by /u/swarthmoreburke\n\n* [What was Rhodesia's end game during the Bush War?](_URL_1_) answered by /u/profrhodes\n\n* [The Rhodesian bush war is heavily romanticised by certain groups - was this true at the time?](_URL_0_) answered by /u/profrhodes\n\n* [How developed were the white areas of Rhodesia?](_URL_3_) answered by /u/profrhodes"
]
} | []
| []
| [
[
"https://www.reddit.com/r/AskHistorians/comments/7ez6dz/the_rhodesian_bush_war_is_heavily_romanticised_by/dq94ta9/",
"https://www.reddit.com/r/AskHistorians/comments/3lshmp/what_was_white_rhodesias_endgame_during_the_bush/cv95cce/",
"https://www.reddit.com/r/AskHistorians/comments/b9j69x/why_does_the_story_of_rhodesia_attract_so_many/ek63ywm/",
"https://www.reddit.com/r/AskHistorians/comments/7sefqh/how_developed_were_the_white_areas_of_rhodesia/"
]
]
|
|
eszrpk | United States officials and politicians grossly overstated Soviet military capabilities in the cases known as the "bomber gap", "missile gap" and "cruiser gap". Did Soviet officials ever have similarly overestimated any U.S./NATO military equipment levels and technologies? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/eszrpk/united_states_officials_and_politicians_grossly/ | {
"a_id": [
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"text": [
"Yes, very much. One example that comes to mind is the \"military-technical revolution\" of the late 1970s and 1980s. Soviet military leaders during the Reagan years in particular were fairly spooked by Western advances in precision weapons, reconnaissance methods, and other technologies which we would now call 'C4ISTAR,' ISR, or some combination thereof: Command, Control, Communications, Computers, Intelligence, Surveillance, Target Acquisition, and Recon. In plain English: all the technologies and methods used to detect a target, see exactly what and where it is, and tell someone to shoot it before it moves. In modern Western defense circles this is now called the *sensor-shooter system* or *network*. The Soviets (and now the Russians) describe this integration as the *reconnaissance-strike* or *reconnaissance-destruction complex.* In the 1980s, the United States began working on this concept under the general heading Assault Breaker. The Assault Breaker program as a whole was designed to combine airborne radars (E-8 JSTARS, Joint Surveillance Target Attack Radar System), computerized command posts, long-range guided missiles (ATACMS, Army Tactical Missile System), and advanced artillery systems like guided anti-tank cluster munitions (DPICM, Dual-Purpose Improved Conventional Munition). Assault Breaker was designed to find and destroy Soviet formations \"in the depths,\" that is, far behind the front lines. The Soviets assessed Assault Breaker, and generic recce-strike systems like it, as *comparably destructive to tactical nuclear weapons*. They weren't entirely *wrong*, either, in many observers' analysis: precision-strike weapons like ATACMS would have been used on targets like armor concentrations, supply depots, second echelon and reserve forces, command posts, and so on, which previously would have been prime targets for small nukes. However, the Soviets undertook serious efforts to counter this program, probably disproportionate to how effective Assault Breaker as a whole turned out to be. JSTARS, ATACMS, and DPICM all turned into complete products, but lots of the other systems were either delayed or nonfunctional, such as the Brilliant Anti-Tank munition.\n\nEDIT: [Here is a concept sketch of the Assault Breaker network](_URL_2_), as a visual aid.\n\nFor further reading:\n\nDavid Glantz, *The Soviet Conduct of Tactical Maneuver: Spearhead of the Offensive*, particularly the first two chapters.\n\nVan Atta et al, \"[Transformation and Transition: DARPA’s Role in Fostering an Emerging Revolution in Military Affairs](_URL_0_),\" Ch. IV\n\nLarry A. Brisky (1990) \"The reconnaissance destruction complex: A Soviet operational response to Airland Battle,\" *The Journal of Soviet Military Studies*, 3:2, 296-306, DOI: 10.1080/13518049008429985\n\nMilan Vega,[\"Recce-Strike Complexes in Soviet Theory and Practice,\"](_URL_1_) Soviet Army Studies Office, 1990.\n\nViktor Reznichenko, Тактика (*Taktika - Tactics*), Moscow: Voenizdat, 1984. (Recommend MJ Orr's translation for RMA Sandhurst's Soviet Studies Research Centre if Russian isn't your strong suite.)"
]
} | []
| []
| [
[
"https://www.researchgate.net/publication/235114019_Transformation_and_Transition_DARPA's_Role_in_Fostering_an_Emerging_Revolution_in_Military_Affairs_Volume_2-_Detailed_Assessments",
"https://apps.dtic.mil/dtic/tr/fulltext/u2/a231900.pdf",
"https://www.researchgate.net/profile/Richard_Atta/publication/235114019/figure/fig6/AS:651202069016578@1532270080306/4-The-Assault-Breaker-Concept-of-Operations.png"
]
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5euvxr | how do nature documentaries capture audio? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5euvxr/eli5_how_do_nature_documentaries_capture_audio/ | {
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" > I can't help but be bugged by wondering how they manage to capture such pristine audio.\n\nTake along a really good microphone with a cover, or even a microphone within a parabolic dish to get audio from far away. Or of course you can dub it in later from audio captured elsewhere in similar fashion.",
"They capture sound from a distance using a directional microphone with a dish to focus on a specific direction. There are added sound design elements. "
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2hqe0b | When did people start realizing that the Soviet Union was going to imminently collapse? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2hqe0b/when_did_people_start_realizing_that_the_soviet/ | {
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"I'm sorry I don't have the answer to your particular and interesting question, but perhaps you might be interested in this slightly relevant tidbit.\n \nIt was George Kennan, a diplomat stationed at the U.S. Embassy in Moscow at the time, who in 1947 put together an analysis of US-Soviet relationship in terms of foreign policy, the *Sources of Soviet Conduct*. He predicted potential high instability on the side of the Soviets, and that there would be no friendship, only rivalry, between the two nations as their ideological and economic systems were simply incompatible. He also predicted that if the U.S kept constant pressure on the USSR, it might force it to adapt and change, perhaps eventually turn into something more approachable. \n \nConsequently, a large extent of U.S. foreign policy towards the USSR was predicated on the assumption that it should be contained, denied the opportunity to spread, and constantly faced with frustration, and it will eventually lead to its collapse. Again, this was as early as 1947.\n\n \n\n > \"It would be an exaggeration to say that American behavior unassisted and alone could exercise a power of life and death over the Communist movement and bring about the early fall of Soviet power in Russia. But the United States has it in its power to increase enormously the strains under which Soviet policy must operate, to force upon the Kremlin a far greater degree of moderation and circumspection than it has had to observe in recent years, and in this way to promote tendencies which must eventually find their outlet in either the breakup or the gradual mellowing of Soviet power. For no mystical, Messianic movement -- and particularly not that of the Kremlin -- can face frustration indefinitely without eventually adjusting itself in one way or another to the logic of that state of affairs.\"\n \n\n-- George Kennan, Sources of Soviet Conduct, 1947\n\n",
" > Reviewing the history of international relations in the modern era, which might be considered to extend from the middle of the seventeenth century to the present, I find it hard to think of any event more strange and startling, and at first glance more inexplicable, than the sudden and total disintegration and disappearance from the international scene, primarily in the years 1987 through 1991, of the great power known successively as the Russian Empire and then the Soviet Union. –George Kennan, 1995\n\nThe collapse of the USSR blindsided many of the foreign policy experts, diplomats, and Kremlinologists in 1991. For example, Paul Kennedy’s 1988 bestseller *The Rise and Fall of the Great Powers* asserted that while Soviet decline was palpable and visible, a collapse was highly unlikely. Kennedy toyed with notions of a Soviet retreat into its own ethnic base in the end of his section on Soviet power, but discounted such a possibility as ahistorical given that all historical precedents of a retreat only came after defeat in a great power war. Kennedy’s myopia is instructive given that many commentators in this period tended to treat both *glasnost* and *perestroika* as evidence of reform and as ushering in a new period of Soviet history not unlike the post-Stalin Thaw. What blinded many public intellectuals was what they only later came to see later: Gorbachev’s reformism were a symptoms of the failures of the late Soviet system. \n\nThe crux of the matter is that the conventional wisdom of 1989-1991 did not seriously entertain the thought that the Soviet elite would voluntarily disestablish its own power base, the Soviet state. Although the Communist Party was no longer had as many barriers to its membership as in earlier Soviet periods, belonging to the Party still was the major glue within the state and administrative apparatuses of the USSR. To democratize the Soviet political system would be to end this monopoly on power. Again, historical precedents made this option seem very unlikely. The 1989 Tiananmen Square crackdown led many commentators to believe that the Communist systems were predicated upon force if put to the wall. In a 22 December 1990 *New York Times* editorial, Richard Pipes incorrectly maintained that Gorbachev had sided with Communist hardliners within the military and KGB:\n\n > The right-wingers -- that is, the generals, the K.G.B. establishment and the nomenklatura of the party -- are moving into a position of authority and forcing Gorbachev to choose, and he has chosen to go with them. If they win, we will see great restrictions on freedom in the Soviet Union and deterioration in foreign relations, combined with increased military activity. The Soviets will put impediments in the way of concluding and implementing various arms-reduction agreements. The Soviet military budget is likely to increase rather than diminish. *Perestroika* has been finished for some time. Perestroika has achieved its goal, which is to dismantle a totalitarian regime, but it failed in putting anything in its place.\n\nThe collapse of the Warsaw Pact states bolstered this pessimism about the Soviet leadership’s commitment to continued reform and democratization. Again, the conventional wisdom held that the Kremlin had seen what happened when there was too lax of an attitude towards open displays of dissidents. The Baltic states’ votes for independence created less confidence that the Soviet government could manage democratic reforms. The *Wall Street Journal* ran an editorial “Tiananmen in Vilnius” in 27 March 1990 which asserted wither Gorbachev will crackdown or face the destruction of the Soviet state. The use of Soviet special forces in Lithuania in January 1991, which resulted in 13 deaths, seemed to confirm this suspicion. Even the conciliatory attitudes towards Gorbachev were predicated on the common logic that there was a limit to Soviet democratization its leadership would not pass. The *New York Times*’s 8 April 1990 editorial “Lithuania Is Not Tiananmen Square” emphasized that:\n\n > Mr. Gorbachev may or may not be willing to go along with Lithuanian independence at some point. It is obvious that whatever his inner feelings, he has no choice but to oppose Lithuania's unilateral declaration of independence. No Soviet leader's power could survive the destruction of the Soviet empire at this time. But he is a far better bet to allow independence, in time, than any of the Russian nationalists, generals and secret police who probably would succeed him.\n\nRunning throughout many of these editorials is the notion that in some form, the Soviet state would continue, either as a federation or under a Deng-like repression mixed with free-market reforms. The third option, dissolution, was invoked only as the *least* likely alternative that would happen only if the Soviet leadership did not act.\n\nAfter the collapse of the USSR, it became a common trope among some Kremlinologists and Soviet specialists to play the “historians should never predict the future” card. However, there also was a subset of public intellectuals that would retroactively claim an acute foresight, especially those on who fell under the rubric of conservative opposition to the Soviet system, such as Pipes. While there is some truth to this claim, their predictions of the bankruptcy of the Soviet system are there in their writings, it misses the forest for the trees. Rereading the conservative analyses of the Soviet Union, two major elements stick out. One, the Soviet state is militarily far more powerful than it was in reality. Secondly, the conservative critiques presuppose that the USSR’s leadership was far more ideologically united and were bound together by a belief in Communist dictatorship. Both suppositions are pretty far off the mark of Soviet reality; although its military was vast, it was not a pliant instrument and was riven with its own institutional conflicts, and the Soviet leadership was far less cohesive in this period. To acknowledge these prescient insights into Soviet collapse, one has to ignore the statements of shrill pessimism that surround them. \n\nThe long and the short of it is most public intellectuals did not really appreciate the Soviet Union was collapsing and only recognized so after its dissolution was a fact. "
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1d1m22 | What was the system for giving African American Slaves or Ex-Slaves second names? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1d1m22/what_was_the_system_for_giving_african_american/ | {
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"Howdy!\n\nThe first census of the United States that attempted to count slaves precisely was the 1850 census. The census wanted the name, age, sex, and color of each person (among other things), which would have us to find the name of slaves in each household. For thirty years before that, there were just numbers. However, a counter-amendment scrubbed that, and only age, sex, and color of each slave was mandated.\n\nNow, there was no system! Long before the United States became a country there were slaves with different surnames from their masters or former masters. Post-Civil War some would choose Lincoln or Freedman, or other educated sounding names. However, the easiest route was the former master's last name, which lead to that becoming the most common option.\n\nIf you didn't choose a surname and were forced to write one down, they would often write the surname of your last master. This was especially true for the Army.\n\nI wish I had a reputable source and not a blog to give to you, but my information comes primarily from institutions and museums in and around the Deep South, especially in Louisiana. In addition, [this](_URL_0_) is a very good source book, albeit expensive unless you buy used."
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1qrkof | what will pot businesses look like in washington and colorado? | So I understand that the stuff is going to be legal (or is), but what will that customer experience be like? Right now, in Oregon, we have the dispensaries, but they're closed-off, very weird places I would feel weird entering. What will the stores in Washington State feel like? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qrkof/eli5_what_will_pot_businesses_look_like_in/ | {
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"Coloradan here. The dispensaries, or medicinal marijuana stores, here are not weird or shady places. Many neighborhoods have multiple dispensaries. The recreational marijuana stores will be modeled after dispensaries. In fact, current medicinal dispensaries will have first dibs on licenses to open recreational stores. A customer will walk into the store and wait in a waiting room until they are next to be served. An employee will make sure the customer is over 21 years old by checking ID. An employee, perhaps the same one, who knows a lot about marijuana use will help the customer determine what product or products they want to buy. Customer A gets a half ounce of marijuana to use over a few weeks because they already know what they want. Customer B gets a recommendation for a specific strain of weed to help him or her fall asleep easier at night. He or she gets a quarter ounce of that and also buys a new vaporizer model to vaporize and inhale the marijuana. \nThese recreational stores will be different from a street dealer or buying from your neighbor because there will be dozens of strains of product available with slightly different effect and there will also be pipes, marijuana-infused baked goods, marijuana drinks, hash (a condensed, smokeable marijuana product), and a number of other marijuana and lifestyle products. When it's time to pay, there will be a 25% excise tax on the price of the recreational marijuana that is in addition to the sales tax of 7 to 8%. A half ounce of medical marijuana is around $90 for premium product here. The recreational marijuana policy makers want the experience to be similar to shopping in a liquor store for marijuana with personalized help."
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g0ns9w | watts vs va | Why is power draw measured in WATTS ( which is volts multiplied by amperage ) but power production or power sources are measured in VA ( volt amps ). Are they not identical? What’s the reason for the difference. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/g0ns9w/eli5_watts_vs_va/ | {
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"For a purely resistive load, like a light bulb or heater, volts times amps equals watts. But many loads are not purely resistive; they can also be capacitive or inductive. By far the most common of the two is inductive: most motors, for example, are inductive loads. These loads consume power but \"return\" some of it without using it. So there's a thing called a \"power triangle\" that shows the relationship between the \"real\" power (measured in watts; this is the actual amount of power consumed), the \"reactive\" power (measure in volt amps reactive; this is the power that gets \"returned\"), and the \"apparent\" power (measured in volt amps: for a purely resistive load, this will match the real power).",
"I will try my first ELI5 answer.\n\nTake your little red wagon, some string, and your little brother and go to the bottom of a small hill. Sit your brother on the wagon and tie one end of the string the string to the handle.\n\nNow, grab the string a short distance from the wagon and slowly walk up the hill, pulling the wagon behind you. Be careful not to jerk or pull too hard.\n\nThe strength the string needs to be, so it does not break while you are steadily dragging the wagon, is the Watts.\n\nThis is slightly like a resistive load like you'd find with a light bulb or a heating element (as others have mentioned)\n\nNow go back to the bottom of the hill. Position the wagon and your little brother in the same place but this time walk back up the hill with the other end of the string.\n\nPull the wagon up the hill hand over hand.\n\nEach pull brings your brother a bit closer and the wagon may even coast a little bit before your next pull.\n\nThis is like an inductive load like in an electric motor or the alternating current in an AC circuit (which 'tugs' 60 times a second).\n\nUnlike when you slowly pulled the wagon up with you, in this case you are tugging repeatedly on the string over and over to get the wagon up the hill. This means the string sometimes needs to be a little bit stronger in order to not break when you pull each time. This is like the Volt-Amps.\n\nThe amount of effort it takes to get you, your wagon, and your brother to the top of the hill is about the same in both cases.\n\nThis is why, in electrical systems, wiring and equipment that needs to handle AC current or feed power to motors, etc, are rated in VA because at certain points in time, they need to handle more. VA is always larger than W in these cases. Situations where there is a steady load VA = W as there is no ‘tugging’.\n\nEdit.. Apologies, I kinda broke rule 4 I think."
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abnnby | Do alcoholics develop kidney stones as often as non-drinkers? | [deleted] | askscience | https://www.reddit.com/r/askscience/comments/abnnby/do_alcoholics_develop_kidney_stones_as_often_as/ | {
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"Good question, I googled and found this:\n\n & #x200B;\n\n > While no direct causality has been found between drinking alcohol and the formation of kidney stones, alcohol can contribute to increased risk for the formation of stones through a variety of avenues. Beer and grain alcohol have an especially high purine count. Purines are chemical compounds that can result in uric acid kidney stones. Uric acid is normally released from the body in the urine, but the presence of excessive purines can lead to the accumulation of the acid and eventually result in a kidney stone. \n\n & #x200B;\n\nYou can read [here](_URL_0_)"
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33wgud | if a nuclear bomb were being tested, and it didn't go off... how is it approached and dismantled? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/33wgud/eli5_if_a_nuclear_bomb_were_being_tested_and_it/ | {
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"Chances are they'd shoot another (small and conventional) bomb at it to blast it into tiny, no-longer explodable pieces, then pick those up and dispose of them.",
"A nuclear bomb is typically set off by a conventional bomb. If the conventional bomb portion failed to fire, they would defuse it just like any other bomb. If the nuclear portion failed to go off, the conventional bomb portion would have scattered the radioactive material all over, so they would have to go recover that material before it poisoned anyone nearby.\n\nDuring the development of nuclear weapons at [White Sands Missile Range](_URL_0_) in New Mexico, they actually built a gigantic container, called [Jumbo](_URL_1_), to catch the nuclear material should the bomb fail to detonate correctly. They were confident that the conventional part would fire, because at that point we had plenty of experience with \"normal\" bombs and didn't doubt it would fire. They were worried that the nuclear portion wouldn't detonate. In the end, though, they didn't use Jumbo, because by the time they were ready to fire they were confident that the nuclear portion would detonate.\n\n > Fears of a fizzle led to the construction of a steel containment vessel called Jumbo that could contain the plutonium, allowing it to be recovered, but Jumbo was not used."
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irf18 | Will bacteria always find a way to become resistant in the end? | I know that through heavy use of anti-biotics certain bacteria have become resistant to them since they become resistant over time.
However there was this article awhile time ago that that talked about cold plasma killing bacteria. Is it scientifically possible that this method could create plasma resistant bacteria? | askscience | http://www.reddit.com/r/askscience/comments/irf18/will_bacteria_always_find_a_way_to_become/ | {
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"It's kind of like saying will human skin ever become resistant to bullets. I don't know too much about cold plasma, but if it perforates the membrane like alcohol does, then there's not really any individual mutation (to my knowledge) that can account for slightly higher survivability among certain bacteria within a population.\n\nDisclaimer: I do not have a PHD.",
" > Is it scientifically possible that this method could create plasma resistant bacteria? \n\n\nI assume you are referring to [this](_URL_1_) article, or a similar one.\n\nQuote from the article:\n\n > Importantly we have shown that plasma is able to kill bacteria growing in biofilms in wounds, **although thicker biofilms show some resistance to treatment**\n\nSo, given this statement, I might ask you: if this actually becomes a regularly used treatment, what do **you** think will happen?\n__________________\nAlso, as far as I can tell, the treatment could only be used for surface infections where you can physically get the torch in position over a localized infection. Perhaps you could go in surgically for internal infections? I'm decidedly not a medical doctor, so I really don't know.\n\nIf it is the case that you could only use it for infections that are easily accesible from without, then that seriously cuts down the number of applications this technology has. This could also mean that the selection pressure exerted by the treatment might be a lot smaller than that exerted by antibiotics, and thus it could take a lot longer for resistance to evolve.\n\n*edit: My obvious implication above was that if thicker biofilms offered some resistance, then thicker biofilms would evolve, and the bacteria could become resistant to the treatment. In [this](_URL_0_) article, however, one of the researchers is alleged to have claimed that bacteria could not develop resistance. The relevant quote:*\n\n > *Eventually, plasma treatments could represent a better option than antibiotics, because microbes will not be able to build up resistance, Ermolaeva said.*\n\n*Perhaps that's true. Then again, one should always be wary when researcher make claims about how effective their solutions to certain problem are, **especially** in medical contexts. I don't really know myself, but I would never count evolution out. It's absolutely unbelievable some of the adaptations living things have come up with.*",
"To add into the conversation, bacteria does not *become* resistant. When you use an antibiotic, the ones that are susceptible will die off, but here's the catch: the bacteria that survived already were resistant, before that antibiotics even existed. So the remaining organisms never *became* resistant, they always were, and since they were the only left, they are left free to reproduce, propagating the specific configuration that allows it to stay alive in face of such and such antibiotics. Minor differences in the genetic make up of bacteria allows them to be resistant, right from start, and not \"become\" resistant. ",
"No. Obviously if you find an entire population and kill them, they can't \"find a way to become resistant.\" They'd just be dead and gone. Of course, that doesn't preclude other bacteria from simply replacing that population/species/what have you with a similar set of genes/characteristics. And it can be damn tricky to kill them all at one go, but it's definitely within the realm of possibility."
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cqtd1h | what causes bond interest rates to fluctuate? | I understand that the reason that Dow J dropped so sharply yesterday was because the interest on a longer term bond was higher than that of a short term bond (or at least that what my personal finance teacher explained it as; inverted interest was the term I think) but what major factors affect the interest rate for bonds? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cqtd1h/eli5_what_causes_bond_interest_rates_to_fluctuate/ | {
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"The more you want a bond, the less the government has to pay you in interest to buy it. How much do I have to pay you per day to pick up dog poop? A lot. Now how much do I have to pay you per day to pet kittens? Very little, because everyone wants to pet kittens! If everyone wants a 10-year bond, they don't need to lure you into buying it by promising a huge interest rate - they already have your excitement to have one.\n\nTo take your question a step further, WHY does someone want a 10-year bond? Or a 2-year bond? It's a safe place to store your money and still get paid some interest in the process (as opposed to a bank account or under your mattress, which pays you essentially nothing). The problem is that more people want a bond that lasts for 10 years than one that lasts for 2 years. Crazy, right? Why would you rather have a bond that doesn't pay you back your original amount for 10 years than one that pays you back in two years? Because more and more, people are convinced that the economy will be terrible in two years, but will be back to normal in 10 years. By buying 10 year bonds, they're guaranteeing themselves that nice little interest rate for 10 years, rather than just two - in case things turn bad in two years and there are no more good interest rates available."
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2u26yk | why doesnt your soda get "shaken up" when it falls out of the vending machine? | When you buy a soda out of an older vending machine (not the ones with the moving tray thing that catches and deposits it), it falls down through the machine and hits through the door and lands in the slot with a bang. It seems like a rough journey. Why doesn't it explode when opened then? If you took that same bottle, shook it up, banged it around a little and opened it, the pressure would cause an explosion- so ELI5 why the vending doesn't do the same. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2u26yk/eli5_why_doesnt_your_soda_get_shaken_up_when_it/ | {
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"Two reasons that both contribute:\n\n1) The vending machine acts as a fridge, and at a colder temperature the CO2 gas requires more force to seperate from the liquid\n\nBut more importantly:\n\n2) The \"drop\" you see in these machines isn't as dramatic as you may think. There are [columns](_URL_0_) of each different type of drink and the bottom drink (the one next in line when the consumer selects that drink) has a 5-10cm fall to the slanted surface that brings the drink to them. \n\nThe ~~kinetic energy~~ forces acting upon it during the 5-10cm fall and sliding down the slant is barely more than how much you impart when you put the drink down, so it doesn't get shaken up that much."
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3vo2c9 | What is the evolutionary background behind Temperature Dependent Sex Determination? | I understand that this phenomenon allows for groups of a single sex to be produced depending on the ambient temperature. But I'm still confused as to how this trait evolved in the first place and why it is restricted to mostly reptiles.
Also, why is the TSD pattern in turtles the opposite from crocodiles and lizards? | askscience | https://www.reddit.com/r/askscience/comments/3vo2c9/what_is_the_evolutionary_background_behind/ | {
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"I would be curious if the lizards realize temperature affected sex. Like would they intentionally control for more females if populations were dwindling. Or for more males if predators were a problem.",
"Let me preface that while I'm a grad student of evolutionary bio, my understanding of the topic is relatively shallow and half of what I'm saying is just an educated guess.\n\n\nWhy mostly reptiles? Well, consider the environment of the developing embryo. TSD would make sense for organisms that develop at variable temperatures. This rules out mammals that develop within a constant-temperature environment (inside the mother). Birds can be ruled out too, as birds are homeothermic, so eggs are incubated at a constant temperature. Reptiles don't incubate eggs and thus develop in a variable environment that could allow evolution of TSD.\n\n\nHow did it evolve? Systems of sexual differentiation are evolutionarily flexible. All it takes is the introduction of a new mechanism to cause differential activation of the developmental pathways that lead to \"male\" or \"female\" development. For reptiles, even if sex chromosomes existed ancestrally, a new system could be take over if it's epistatic to the first.\n\n\nBut why would TSD be more fit than genetic sex determination? (otherwise it wouldn't be likely to become fixed)? I don't think there's a specific consensus about that. It could be that sex-specific fitness is correlated with the environment, and temperature can be a cue. The following is just an example, not based on anything specific: Say it's more beneficial to be born early in the season (when it's cooler) if you're a male, so you can grow larger before competitors, but better to be a female later in the season (when it's warmer) when predators are rarer. This could favor TSD where males develop at cooler incubation temperatures, and females at warmer incubation temperatures.\n\n\nWhy is it opposite in turtles? No clue. I remember reading about red-ear slider turtles and how TSD is correlated with epigenetic changes (methylation I think) to promoters (I think?) for aromatase, which converts testosterone to estrogen. Opposite patterns could easily be achieved by these changes occuring in silencers vs promoters/enhancers, so that the same temperature cue in one organism results in either constitutive (or enhanced) aromatase expression, or silencing of expression.",
"Interestingly, there's some idea that temperature dependent sex determination is the ancestral state, and that other forms of sex determination evolved from that. The idea is that sex is most useful in times of environmental stress (ie the chances of passing on genes is better if they are mixed with lots of other genes in a really diverse set). But there's still a lot of research being done on the origins of sex and sex differentiation (note that these are also separate questions, since organisms can produce both gametes as well). \n\nUnfortunately, I got most of this from a lecture so I don't have a citation.",
" > Also, why is the TSD pattern in turtles the opposite from crocodiles and lizards?\n\nI did some work with TSD as an undergrad, and my professor explained this to me. Nobody knows for sure, but here's a hypothesis.\n\n[This image](_URL_0_) from Wikipedia shows two different patterns of TSD. Pattern I shows turtles, a reversed Pattern I would represent most lizards and crocodilians. They seem completely opposite. But some reptiles (American alligator & leopard gecko, according to Wikipedia) show Pattern II, where especially cold or hot temperatures create females and median temperatures create males.\n\nThese patterns are genetically determined, and can shift up or down, stretch or compress. It's easy to see how turtles could have shifted their TSD pattern leftward (toward lower temps) to create what looks like Pattern I. Crocs and lizards could have done the same in the opposite direction. The \"other side\" of the pattern may still exist in these groups, but at temperatures they would never encounter naturally, or which would be dangerous for the embryos.\n\nThis, by the way, suggests part of an answer to\n > why it is restricted to mostly reptiles\n\nTSD depends on reptiles' body temperature as embryos. It only works if embryos can develop properly at a range of body temperatures, which reptiles can do. Their physiologies work fairly well at various temperatures. Not so in some other groups. Warm-blooded animals such as mammals and birds have bodies finely tuned to work at a specific temperature. If our own internal body temperature changes even a few degrees, we either have a fever or hypothermia, either of which can be very bad. Even some fish, which are cold-blooded, remain at basically the same temperature because the water of their habitats don't change much, so they are sensitive to changes in body temp.",
"though several people have given good information about how the biological process works and why it is restricted to reptiles, I notice that no one has yet used the word 'spandrel'.\n\nSo in answer to the question of why this would evolve: it's probably a spandrel.",
"If you figure it out it's an easy PhD. Currently there is no answer and probably isn't a good cookie-cutter answer that has to do with fitness. It is logistically hard to test because you can only take eggs once a year to run experiments on. It is entirely possible that TSD did not evolve to aid fitness of the species and is a side effect of some other process. Like you said, red eared sliders are opposite of alligators, and I think leopard geckos can produce females at extremes. I'm sure somewhere an individual turtle species is the opposite of red-eared sliders. Try to apply a theory to one species and realizing it is contradicted by another makes there seem to be no direct apparent rhyme or reason to having a sex pop out at a particular incubation temperature. Fun fact, if you incubate at certain temperatures 50% will be male, 50% female, and all ratios in between depending on which direction you go. You can even take one egg out of a batch that is incubated at a 100% female temperature and turn the gonads back to male (there is a point of no return and also intersex is possible).\n\nIn general scientists and PhD seekers are just trying to elucidate the molecular pathway for the sake of science (and let's be honest-further NIH grants are needed to eat). The endgame isn't so much about fitting it into evolution and fitness. So yes, I mean your question reminds me of my mindset and how I thought after learning the general theory and examples taught in Bio: Intro to Genetics. That is how clean science CAN be but science rarely can be boiled down to something as meaningful and/or obvious. \n\nSource: Aborted 100's of turtles/geckos/alligators during varying stages of development and incubation temperatures to harvest tissue for experiments."
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vreyb | What are the chances that a ray, if projected outwards in a random direction, will hit a planet before it exits the observable Universe? | Assuming the ray is infinite for the sake of this hypothetical. And as for which direction, why not directly upwards from the Statue of Liberty?
Sorry if my question is not scientifically intelligent, but I tried to word it as well as I could. | askscience | http://www.reddit.com/r/askscience/comments/vreyb/what_are_the_chances_that_a_ray_if_projected/ | {
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"If you assume that the ray doesn't diffract and stays the same size like a laser beam I would estimate that the chances are as close to zero as you can get.\n\nIf it does diffract and spread out - like the beam from a flashlight then the probability becomes almost 100%",
"Let's say that there's a planet every 5 light years (an overestimation, certainly), and let's say that planet is the size of jupiter. For objects much smaller than their distance away, the angular size is approximately the diameter of the object/distance to the object. So let's take the infinite sum (diam/dist+diam/dist\\*2 +diam/dist\\*3 +...) = diam/dist( 1 + 1/2 +1/3 +...). Now the following sum is divergent (meaning it doesn't terminate if there are infinitely many terms), so let's assume that we stop counting planets within the radius of our galaxy (and assume that additional planets represent a finite series of truly pointlike sums (thus summing to no additional angular area). So 250,000 ly/5ly = 50,000 terms in the series, which is the 50,000th Harmonic number, about 11.4, so diam/dist*11.4\n\nNow the solid angle subtended by that angle is 2\\*pi(1-cos(theta)). Now for these ridiculously small angles, cos(theta) ~ 1-theta, so 2\\*pi(1-1+cos(theta)~ 2\\*pi\\*diam/dist\\*11.4. \n\nSo throwing that into wolfram alpha, I get about 2.1 \\* 10^-7 steradians. A whole sphere is 4 pi steradians, so with these **vast** overassumptions, we show that planets cover about (5/3)\\*10^-8 of the sky, so ***no more than about .000001667%***"
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dvm001 | what is the rationale behind kicking out a business from a strip mall/shopping center and leaving the space to sit for months/years? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dvm001/eli5_what_is_the_rationale_behind_kicking_out_a/ | {
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"If it’s empty, they get tax write offs. Maybe they want to empty out the whole place and sell it for multi-family housing development."
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5mn1bl | how does a game like call of duty have practically no online delay at all while when playing a game like nba 2k17, multiplayer modes experience about a full second of delay between when the button is pressed and when the game responds? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5mn1bl/eli5_how_does_a_game_like_call_of_duty_have/ | {
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"Err. I haven't noticed this to happen in any online game so thought I'd start with that. \n\nVideo games online don't use much bandwidth so getting a faster connection doesn't really impact them that much. (Unless it comes with better latency)\n\nGames are mostly impacted by latency or ping, this is how long it takes for a piece of information to get from your computer to the host.\n\nSome games select a player with a good connection as a host and others use a central server. \n\nThe graphics are rendered locally with just the information about what movements the players are making sent back and forth. \n\nHaving played NHL, Madden, and NBA 2k I have never noticed long delays. Are you playing one of these games on a computer and the other on TV? Delays in console gaming especially can be very long if your TV isn't in \"game mode\"\n\nMost modern TVs put a 1/2 second delay on what they show so that they can upscale, and insert additional frames to make things look smoother- this obviously negatively impacts gaming. \n",
"There are mutliple ways of how you setup your networking when implementing networks for a game.\n\nOne of the most important, if not the most important aspect when doing this is if your game uses deterministic lockstep.\n\nWhen using a deterministic lockstep networking model, every action your client wants to do, has to be authorized by the authority of the game session, which in a client-server structure would be the server.\n\nIf you use peer-to-peer the authority of the gamesession would be one of the players who basically runs a server either within the client itself as paralel thread or as a dedicated program which is initiated by the gameclient which is called a child process (the gameclient would be the parent process while the server executable would be the child process).\n\nEitherway, when a gameclient wants to do something, it first has to get an ok from the authority. So you press a button which does the \"pass\" in a basketball game, and before it gets executed the authority will check if you are allowed to do this, and give you an ok if you are. Once the ok arrives, your client starts to execute the pass command you just game.\n\nAs you might already see, latency and server overload might cause the ok message to take a while. And until then, nothing is displayed for you. On the upside is, that what you see, is actually what is considered the correct state of the game... at all times. When you see a certain player holding the ball, you know, that this player hold the ball.\n\nNow there is another common way of doing network, which is predictive networking. As the name suggests your client predicts certain things. Movement for example. You move your character, and the client predicts that the authority does give it's ok, and starts displaying it right away. Or if you do an invalid command like trying to walk through a wall, it will predict that the authority will not give it's ok, and stop your model from going through the wall.\n\nNow the first thing is, with that your current gamestate will always be out of sync unless nothing moves or changes in any way. This often requires the authority to give a bit of leeway. Ever wondered why people can shot you while you were already behind a wall on your screen? Well the authority got a \"hey I shot this guy\" and due to the out of sync nature the authority decided that yes, indeed you got shot as the timeframe in which your client said \"I walked behind this wall\" and the other client said \"I shot this guy\" is within the margin of error. Without that margin of error you might never hit someone, as nobody would be where your client shows them, unless they stand still. And if you for a longer period of time not get updates, your client might run completely out of sync, in which case it needs to be resynced by the latest state from the authority, which is often shown as everyone either moving really fast or teleporting around.\n\nBut on the plus side is, that any action done on your side is immediatly reflected on your screen.\n\nAlso those two might be combined in certain ratios. An example would be Guild Wars 2 which allows predictive movement, but requires determinitis lockstep actions for skills.\n\nWhen you have a lag or a disconnect, you can still move as if nothing happened, and in case of a lag, the server might actually accept your movement if you could have reached that place within the timeframe in which no updates arrived. But at the same time using skills will not work, as you won't get an ok from the server."
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8cpf94 | how does saudi arabia make sure all of their expats like engineers, businessman, and english teachers follow their religious laws? | I heard that personal computers are all inspected for adult content and images. How are all expats monitored? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8cpf94/eli5_how_does_saudi_arabia_make_sure_all_of_their/ | {
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"It only 'counts' inside the country. If you hang out with Arabs, you quickly learn they are all hypocrites and will happily travel to a less restrictive country where they get to drink and party.",
"Expats from Saudi Arabia, or those in Saudi Arabia? They have no control over those that have left their country, but for those moving to their country they do have the ability to check their homes, computers, phones, etc for what they deem to be illegal. ",
"if you are talking about alcohol and clubs, then there is no place to get booze excepts embassies. embassies usually hold parties and alcohol is served there, some is smuggled through. and there are compounds, which pretty much is a different countries inside saudi arabia.\nif you are talking about pornography then there is good old vpn, some saudis might even recommend you something. \nI have asked many foreigners who work in saudi, the worst part is that there is no night time activities like in the western world, and most go to dubai or kuwait or bahrain to have a good time. ",
"It's hard to wrap your head around if you assume the end goal is maintaining absolute purity of the country & laws are enforced fairly & equally. It's much simpler to understand if you view it as a tool of control.\n\nIf you're a foreigner with money & don't make enemies of the wrong people, you can get away with a lot of things as long as you do them in private. It's only after you piss off the wrong people or are stupid enough to do things publicly that they start coming after you to make an example out of you.\n\nSaudi Arabia isn't a modern Western Liberal Democracy. It's a theocratic absolute monarchy where the royal family literally owns the majority of the country and they aren't bound by pesky details like a \"Constitution\".",
"The main rules we had to follow was this: don’t flout the rules publicly. If you were drunk in your home, nobody cared as long as you didn’t sell alcohol to the locals. And don’t be drunk on the street. \n\nDon’t, don’t, don’t get caught drivinf under the influence. \n\nLong sleeve pants were strongly encouraged, but with all the heat out there, it was a great idea anyway! (Bare skin + vinyl car seat in July = PAIN)\n\nMost bigger companies paired the new folks up with a more experienced family who helped get you up to speed with the society’s expectations. Sometimes you got a welcome book from the company, too - giving you advice and guidance on not breaking the laws. \n\nThe mutawwah these days have much less power, you won’t get arrested for inappropriate dress; harassed, sure, but not as bad as before. \n\nAlso, depends on what city you’re in; the coastal cities are more liberal than the central highlands. \n\nYour luggage gets inspected at the airport (well, xrays now) but you’re not followed around. \n\nSource: 20+ years in KSA",
"For one, many foreign workers live in special 'compounds'. Basically an area where foreigners live. The best analogy I can think of is like a gated community in the US. So generally, many of the stricter laws don't apply. Like if you're a white American woman working in Saudi, you will probably live on a compound and not have to wear the niqab.\n\nDrugs and alcohol are illegal, but I mean, drugs are illegal in Canada too. People still get drugs and do them. Saudis get drunk too. They also have prostitutes and anything else you can think of. What makes you think Saudi is any different? Yeah, the punishments are harsh and you don't drink in public, but people have their own supply in their own homes. It's risky to get it into the country, like smuggling weed across the US border, but people do it. People also make their own. Saudi is not as religious as people think. Islam has a real concept of hiding your sins. The 'worst' thing you can do is talk about your sins. So people drink, fuck, drugs... and the culture and religious custom is to just not talk about it. Flout the rules publicly and yeah... you will get hit hard. \n\nInternet is something that foreigners are probably not exempt from. im not privvy to their surveillance programs, but i assume they watch all. But like all countries, people use VPNs or other stuff to bypass it. \n"
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3ev7rz | mountains are brown, yellow, and green and definitely not blue or purple, yet they look purplish-blue from far away. why is this? | Noticed it on my drive home in the desert...never occurred to me to actually ask why... | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ev7rz/eli5_mountains_are_brown_yellow_and_green_and/ | {
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"Because if they are far away, there's more stuff i.e. atmosphere between you and the mountains and thus it gets a slight bluish tint. It's the same reason why the sky is blue. Blue wavelengths are scattered less easily than red ones so they 'dominate'.\n\nYou'll notice that not only mountains appear bluish at a distance but really everything does.",
"If the mountains are really far away the volume of air between you and them is so high that it absorbs most of the visible light of the spectra but the blue light. With other words it is a result of the presence of air and its particular molecular composition. "
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518gob | now that mother teresa is saint teresa, how does her image change in the minds of christians? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/518gob/eli5now_that_mother_teresa_is_saint_teresa_how/ | {
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"Catholics and Christians already held Mother Teresa in a Saint like regard, so her getting actual Sainthood doesn't actually change very much.\n\nAs for her position, technically she isn't \"worshiped\", but she will be prayed to for people seeking guidance, and she now has a \"Feast Day\" (September 5th) where Catholics Bishops can decide to hold a feast in her honor.\n\nNo Church is actually obligated to host a feast for her, the Catholic Church currently has [810 saints](_URL_0_) and celebrating all of the Saint feast days would mean having a multiple feasts on every single day of the year, so the Bishops pick and choose which saints will celebrate which feast days are and are not celebrated.",
"For Protestants nothing changes. We do not celebrate or honor the Saints, and some Protestants view doing so as idolatry. Many think the work that she did was great, but it does not go beyond that. \n\nFor Catholics she is among the list of people that can be prayed to for guidance or help. But being canonized does not really change much, because people had to have already had high opinion of her for her to be canonized. ",
"If you admire Mother Teresa, you really might want to [inform yourself better.](_URL_0_)\n\nAmong other things, she let people suffer needlessly because she was obsessed with the Christian view of suffering as a virtuous act. Less charitably put, she tortured people because she found their pain beautiful."
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1x1tj4 | Why are peasant rebellions so present and successful in Chinese history as opposed to European history? | Or is it only an impression? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1x1tj4/why_are_peasant_rebellions_so_present_and/ | {
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"I think the success is an impression. Because of China's myriads of historical peasant rebellions, only two can be called successful - the Red Turbans who overthrew the Mongol Yuan Dynasty and established the Ming Dynasty, and the communist revolution which established the PRC (and even that one, you can argue either way because the PRC did not start as a peasant based organisation, it just became that way when the shift in communist support happened after the White Terror).\n\nThe other famous peasant based rebellions - the Yellow Turbans, the Kingdom of Heavenly Peace, the Chen Sheng rebellion at the end of the Qin Dynasty...did not eventuate in stable dynasties.\n\nAs for why they're so present, I don't know of established historical theories so I'll let others take a shot at it first. I'm trying to formulate an argument about how the difference between mandate of heaven vs. divine rights of kings may affect this. \n\n\n\nedit: okay I've come back and am forced to conclude that the mandate of heaven system and relative meritocracy of feudal China vs. medieval Europe *must* have a role. Particularly, the mandate of heaven is a system which means that the Emperor rules by the will of heaven but this will is not eternal and can be withdrawn. This is usually tied up in the Confucianist system of morality where the personal virtue of the Emperor/his predecessors affected the mandate of Heaven. \n\nSo basically things like natural disasters, hardships etc. are a sign that the mandate of heaven for the dynasty has been withdrawn, and uprisings can in the eyes of rebels be justified that way. The Records of the Grand Historian by Sima Qian records that the anti-Qin rebels found a fish with a message in its gut saying that the Qin Dynasty must be overthrown. Records of the Three Kingdoms by Chen Shou also records the Yellow Turban rebels claiming portents etc. for the end of the Han Dynasty, and these claims/rebellions generally coincide in times of hardship/misrule. So this fallibility of the Imperial clan is one factor which leads to rebellions being seen as okay.\n\nThe second factor then is that starting from the Eastern Han Dynasty there really wasn't that much in China in the way of nobility - ie. princes, dukes, barons and what have you. There were wealthy land owning families, scholar families (the gentry), merchant families etc. but really you couldn't call them feudal nobility like you could with the European aristocracy. So with this kind of semi-meritocratic society there is no need as there is in Europe to find alternative monarchs based on bloodlines and claims etc. Of course it generally *helped* if you could claim you were from a better family. eg. in the Three Kingdoms era the three competing dynasties had their founders descend respectively - from the adopted son of a eunuch (not something very respectable), basically a commoner (who had ties to the royal family like a century ago) and from a merchant (again, not very respectable).",
"It could have been related to the \"equal field system\" that was set in place as a tax system. Land was distributed equally to cultivators (males who were able to farm), who paid taxes in labor and grain. However, because the scholar/elite class were exempted from paying taxes, yet were able to gain greater amounts of land through \"grants\" from the emperor, they levied this heavy tax weight back onto the peasant class. The system was thus unequal, times get hard, and the peasant class would rebel. \n\nAnyway, this is the theory I remember from my Chinese history class. Might not be 100% correct but I am sure it is along these lines. I double checked this theory from the source below. \n\nSource: Craig, Albert M.. \"The T'ang Dynasty.\" The heritage of Chinese civilization. Upper Saddle River, N.J.: Prentice Hall, 2001. 58-59. Print.",
"Impression is one of them. The unification of China goes all the way back to the time of the Roman Republic. That's a lot of history compared to the relatively short history of modern European nation-states, which makes for a lot more opportunities for successful peasant rebellions.\n\nAlso, in the post Roman world, Europe was far more fragmented compared to China. Whereas China maintained a relatively unified culture, government, language, etc., Europe was splintered into many different feudal states with varying cultures, language, and government. \n\nKeep in mind that China has historically encompassed an area the size of Europe and a population to match as well. A peasant rebellion in 800AD in say, Normandy, may not be much of an concern beyond the Duke of Normandy and may have little influence on a county in Burgundy which at the time would have shared a different kingdom entirely. However, in that same time, a peasant rebellion in Hubei could ignite one in Hunan and spread across China who were all under the rule of the same Emperor.",
"Supplementary question here, how are peasant rebellions represented in Chinese literature and popular media historically speaking?"
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6hvqba | What is alcohol actually doing to our brains when we drink? And why does it improve moods so quickly? | askscience | https://www.reddit.com/r/askscience/comments/6hvqba/what_is_alcohol_actually_doing_to_our_brains_when/ | {
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"Ethanol (common drinking alcohol) is a drug that interacts with a variety of neurotransmitter systems; most importantly GABA-a, but also serotonin and NMDA receptors.\n\nYour body produces a molecule called GABA(gamma aminobutyric acid), which acts as a neurotransmitter. Neurons with GABA receptors are ubiquitous throughout your body; GABA acts as the major inhibitory transmitter in your body. When GABA binds to it's receptor a gated ion channel opens, releasing Cl- ions across the neurons membrane. This drops the neuron's membrane electrical potential, and inhibits any further action potentials to neighboring synapses. ~~The molecular structure of ethanol has similar steric (it can fit inside the receptor) properties as GABA. When it binds to GABA-a receptors, it elicits a different response~~* (this can be generalized to any molecule/drug with similar chemical structure to a neurotransmitter. Compare the chemical structure of serotonin and the trpytamine class of hallucinogenic drugs for an obvious example.) \n* This is wrong. See /u/ADplusP 's comment below\n\nAs /u/callmemateo points out, the limbic system and frontal cortex are two of the functional brain areas effected by alcohol intoxication which give rise to the subjective effects.\n ",
"And why does it affect me so differently? I've never enjoyed alcohol, though I've had my fair share of it. I don't just mean the morning after, I mean the moment i start to feel the effects I get flush, pale, sweaty, and generally not good feeling. These days, at 28, I can't even have a shot without feeling utterly terrible."
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9gw1at | When and how did the names for aircrafts go from being nouns (Hurricane, Spitfire) to alphanumeric codes (F-16)? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/9gw1at/when_and_how_did_the_names_for_aircrafts_go_from/ | {
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"You’re confused. The two planes you listed with names are British. The British have retained the name only system (e.g. the Eurofighter Typhoon).\n\n Meanwhile the US Army air corps/air Force has used a type-number designation since after the First World War (e.g. the F-16, B-52). The letters stand for the type of aircraft it is f - fighter, b-bomber. \nIn addition to the type-number designation US planes also have a name (the F-16 is the “fighting falcon”, the B-52 is the “stratofortress”). ",
"As noted, the British (Spitfire, Hurricane) and American (F-16) air forces have different aircraft designation systems. If you're interested in the reverse of the question, \"When did (British) aircraft names go from alphanumeric codes to nouns?\", the answer is 1918.\n\nDuring the First World War manufacturers all had their own naming schemes with a variety of letters and numbers representing different elements. To pick a few examples - the Handley-Page Type O, Royal Aircraft Factory R.E.8 (its eighth \"Reconnaissance Experimental\" type), Airco DH.9 (the ninth type Geoffrey de Havilland had designed for the company), Avro 504 (not the 504th Avro design, the series started with the Avro 500 for some reason), Vickers F.B.5 (\"Fighting Biplane\") etc. Many acquired unofficial nicknames like \"Harry Tate\", \"Nine Ack\" and \"Gunbus\"; Sopwith types in particular seemed to lack an official alphanumeric designation so were known as e.g. the Tabloid, Pup and most famously Camel (from the \"hump\" in front of its cockpit).\n\nIn 1918, with the formation of the Royal Air Force, the Air Ministry decided to standardise naming as the designer/manufacturer followed by a nickname. The nicknames were to follow a pattern, such as zoological names for fighters (with certain exceptions, e.g. birds of prey were already used by Rolls-Royce engines), geographical names for bombers, and at first initial letters were assigned based on manufacturer. This was fine for the firm of Vickers naming bombers geographically starting with \"Vi\" such as the Vimy and Virginia, but the firm of Boulton & Paul obviously struggled with zoological names starting with \"Bo\" - their first fighter design was the Boulton & Paul Bobolink. The naming system therefore evolved over the 1920s and 30s to be more practical (removing manufacturer-specific initials; alliteration would continue to be a theme, but not a rule), and inspiring. Being confronted with a Bobolink would hardly be a terrifying experience (except for a field of grain), the zoological names for fighters were dropped in favour of names \"indicating speed, activity or aggressiveness\" - the Gloster Grebe and Gamecock were succeeded by the Gauntlet and Gladiator. That's how the Spitfire and Hurricane got their names.\n\nOver in the US the Army Air Service adopted the Mission Letter(s) - Number scheme, which also evolved over the 1920s and 30s to the familiar system in place for the Second World War - B (Bomber), C (Cargo), P (Pursuit, or fighter) etc. resulting in the the B-17, C-47, P-51 and such. The Navy had their own alphanumeric scheme that incorporated a letter for the manufacturer - the F4F was the fourth Fighter type built by Grumman (who got the manufacturer letter 'F'), the SBD was the first Scout Bomber built by Douglas. US aircraft also had common names, often bestowed by the manufacturer - B-17 Flying Fortress, F4F Wildcat etc., and of course aircraft tended to acquired a variety of unofficial nicknames from their operators (often less than flattering). \n\nThe Second World War resulted in an interesting overlap (and sometimes collision) between the systems with large numbers of US-built aircraft in RAF service, ordered before the war and later supplied via lend-lease. The RAF used their standard naming scheme with an appropriately American twist, so bombers got US town names (Douglas Boston, Martin Maryland and Baltimore, Consolidated Catalina). The aircraft that would become the P-51 was first ordered by the British, and their name for it (Mustang) would stick in the US as well. Where aircraft had established names they were generally retained; the B-17 and B-24 in RAF service were the Fortress and Liberator respectively, despite not being geographical, the P-38 Lightning and P-47 Thunderbolt appropriately indicated \"speed, activity or aggressiveness\" anyway. Most aircraft ended up with the same name in both air forces; it was briefly suggested that the Bell P-39 should be named Caribou in RAF service, but this was swifly dropped in favour of the manufacturer's Airacobra. US carrier aircraft were initially named along British lines, seabirds for fighters and fish for torpedo bombers - the F4F Wildcat became the Grumman Martlet, the TBF Avenger was the Grumman Tarpon, but in 1944 the American names were adopted instead. A few aircraft retained different names; the Curtiss P-36 Hawk and P-40 Warhawk were slightly tweaked to Mohawk for the former, Tomahawk and Kittyhawk for the latter in the UK, and the C-47 Skytrain, the military version of the DC-3, became the Douglas Dakota."
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46qul7 | uk vote on leaving the eu - brexit | Today it was announced that there will be a referendum for the UK to leave the EU on June 23rd. All related questions in ELI5 will be forwarded to this sticky thread. Please read the comments on this thread and if your question isn't already covered please ask it as a question in this thread.
Thanks! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/46qul7/eli5_uk_vote_on_leaving_the_eu_brexit/ | {
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"ELI5, why has this referendum come about? What lead up to it?",
"* What is a referendum?\n\nA referendum is when the electorate (general public who can vote), or the parliament (although usually MPs can't vote, but not in this specific referendum), vote on a specific issue, such as, for example, a law. \n\nUsually, it's basically that you choose \"yes\" or \"no\" on a particular law, for example, but sometimes there can be multiple choices as well.\n\n* What is the European Union?\n\nA political and economic union (or actually the economic part is only in the European Economic Area) between multiple countries, and most of them are usually located within Europe. Currently, there are 28 member countries. The idea of it is that basically those countries can work together, make laws which apply to all of them, have a unified trading market, have the same currency (the euro, of which 19 member countries currently use it), etc.\n\n* What is going to be asked in this UK referendum?\n\nThe exact question is \"*Should the United Kingdom remain a member of the European Union or leave the European Union?*\"\n\n* Is the parliament only the people who can vote on that question?\n\nNope, if you're a UK citizen who's over 18 years old, or you're a UK citizen who's living abroad but have done so for less than 15 years, or a commonwealth citizen residing in the UK, then you are able to vote.\n\n* Should the UK leave the European Union?\n\nSome people say that yes, it should, because they say that the European Union has too many rules for businesses, and they also say that even though the UK pays lots of money as membership fees, they don't get much stuff in return. They also want to reduce the number of people coming to the UK for work (as to basically get to control the borders and not have \"free movement\", which is a thing in the European Union wherein you don't need a visa to go to from one member country to another), etc.\n\nSome people say that no, it shouldn't (and that includes the UK prime minster, David Cameron, as well), because then it's easier to trade between other member countries, and that also that the immigrants who're coming for work actually help to boost the economy.\n\n* So, should the UK leave or not?\n\nIt depends, as there are plently of arguments on either side saying yes, it should, and no, it shouldn't.",
"If the UK leaves the EU, what will change for the UK citizens living in the EU and vice versa?",
"What exactly is this \"deal\" that Cameron has got? How does it change the relationship with the EU and what does it allow the UK Parliament to do which it couldn't do before?",
"What affect will this have on Ireland? Especially the border between the Republic and the North?",
"Why does the EU event WANT the UK to stay? I got the impression that the Brits have already bullied the EU into giving them special treatment multiple times. So... is keeping the UK in the EU really worth it?",
"Will non UK citizens who remain in the UK on some sort of visa likely to be entitled to free health care etc if they remain or will life become harder once on a visa / different terms and thus encourage people to leave the UK?\n\n(I'm thinking families who have lived here for years and work here that may suddenly find it difficult, and have to return to their home land, which may put a strain on businesses) ",
"Can someone explain to me the reasons the UK would want to stay in the EU and the reasons they would want to leave?",
"Can anyone give an idea of what applying to university will become post referendum?\n\nAssume that I was offered a position today, but started in the autumn, how would this affect my studies?",
"London Mayor Boris Johnson said he is campaigning to support the \"brexit.\" How important is this news and how influential is his opinion?",
"I guess what really blows my mind is Europe has the potential to be the most powerful state in the world economically, but the constant divisions and infighting leave it mostly impotent ",
"Why would England beg Scotland not to leave the UK, but the same people want to take UK out of EU?",
"And so Europe gets a little closer to another war between us.\n\nIt may be that the EU kept us together for so long (and ofc the nukes)",
"The way I understood it was if Scotland left the UK then we (England) would most likely go into another economic depression. Would any sort of similar thing happen if the UK left the EU? If so, what? And as a more general question what are the major economic effects on the general public as a whole (including things like if, how and when currency will change, if and how earning change etc.)?",
"Britain leaving the EU; is it the UK (England, Scotland, Wales, and Northern Ireland) or just England? What are the possible ramifications for 1) the UK, 2) Republic of Ireland, if it is the UK, 3) the rest of Europe, with regards to travel/visa arrangements, trade, etc?"
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7witzr | Do babies remember their parent's faces and voices before four months? | I read that most babies develop short-term memory around four months into their life. However, would a month-old baby be able to remember who is and who is not their parent? And if that baby were kidnapped would it know that the person who is handling them is not their parent?
Disclaimer: I am not planning to kidnap a baby. I'm writing an essay and this became relevant to a point I am trying to make. | askscience | https://www.reddit.com/r/askscience/comments/7witzr/do_babies_remember_their_parents_faces_and_voices/ | {
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"Also if someone has a source for their answer, that would be a huge help. Not trying to be picky though. If it's difficult at all to find one then it'll be no issue. I'm mostly just hoping for an answer. Thank you.",
"I haven't read it in a while and don't have a copy to answer your question directly, but a fantastic book called \"The Self Illusion\" by psychologist Dr. Bruce Hood goes into great detail about this topic. If someone doesn't answer the question to your satisfaction then I highly recommend checking it out. Very readable book. Super interesting. "
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1923h4 | Explain to me the science behind something I witnessed this morning in my water bottle | I'm not really well versed on science, so you'll have to be patient...
Last night I left a bottle of water in the freezer, I meant to take it out but forgot to. This morning (8 hours later) I went to the freezer to get the water. When I opened I saw to my surprise that it wasn't frozen solid as it usually is, it still seemed to be all liquid, even with bubbles. I took it out of the freezer and before my eyes, the clear liquid transformed into mushy opaque solid (with around the consistency of snow cones).
Any explanations? | askscience | http://www.reddit.com/r/askscience/comments/1923h4/explain_to_me_the_science_behind_something_i/ | {
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"You most likely experienced a [supercooling](_URL_0_) phenomenon. This happens, simplistically, when the liquid has nothing to grab onto (a bit of dust, something like that) to form crystals or other ordered structure like ice. When you took it out, you probably agitated it enough that it found something to form crystals around, and those ice crystals are what you saw (they're like snow, of course).\n\nPretty cool that you watched it happen!"
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2yh4ny | What evidence is there, that Carthage sacrificed humans? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2yh4ny/what_evidence_is_there_that_carthage_sacrificed/ | {
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"Historically, the practice of child sacrifice is attested by Greek historian Plutarch, and Carthaginian Christian historian Tertullian, and Orosius, Philo, and Diodorus Siculus. Some scholars contend that these records are exaggerated remembrances and propaganda by the Romans against their arch-nemesis.\n\nHowever, archaeologically, there is a vast graveyard of cremated human remains, mostly infants and children. It is referred to as the \"Tophet\", after the word for such a thing found in the Hebrew Bible. Some scholars have contended that it wasn't a religious ritual, but rather a graveyard for infants and children who died of natural causes. This is the official view of Tunisia, the modern country where Carthage is located (mostly because it's not exactly savory to be host to a massive child sacrifice cult site). However, I believe the archaeological evidence points to ritual child sacrifice. There are an estimated 20,000 urns filled with cremated child remains in the Carthage tophet alone, and there are a couple other Tophet-like sites in other Phoenician/Canaanite cities around the Mediterranean.\n\nThe remains do include some small animals, and the argument goes that if the animals were sacrificed, then it is logical that the children were too. There is also a correlation between the rate of cremated children and the well-being of the city. When the city is in dire straits from war or natural disaster, the rate of cremated children in the Tophet skyrockets.\n\nAnother argument from Patricia Smith is that the infant bones are from children aged two months, which is not usual for infant mortality as previously reported, indicating sacrifice. The original round of skeletal analyses were very contradictory, and the original scholar who performed them (Schwartz) has contradicted himself and his own results several times, and has not produced a consistent aging of the cremated children, despite making several attempts to do so. His efforts were so inconsistent, the directors of the excavation actually removed him from the project and brought in other scholars. Despite this, he continues to publish studies on the Tophet. Personally, given that I know most of the scholars involved, I would not trust Schwartz's work on the Tophet, but rather would look to Pat Smith and Sherry Fox for much better analysis. The most recent work (done by Sherry Fox and Patricia Smith) has indicated that the children were healthy at the time of death, and of an age when infant mortality is not usual. The fact that so many children are of the same age at death, when this age is not associated with infant mortality indicates a purpose behind the deaths and cremations. There are just too many children, over a long period of time, all of a similar age (and not fetuses, but children who have survived the first few months), all bearing no skeletal signs of deformity or disease or injury that would have indicated death from some other method. This coupled with the historical accounts of child sacrifice are the evidence.\n\nWhy did they sacrifice children? Notice I mentioned before that the rate of child sacrifice is inversely proportional to the wellbeing of the city. Great distress requires great sacrifice, according to Carthaginian religion. When your city is in extreme peril, and you need to get the god's attention, you make a sacrifice. For them, the greatest possible sacrifice was a child. It was not undertaken lightly, but was the most visceral, last-ditch effort to call to their god for help.\n\nIt's a controversial and divided subject, to be sure. But the majority of scholars who have worked on it who are unaffiliated with the country of Tunisia are of the opinion that child sacrifice took place. The major opponents to this have not done particularly exemplary work on the subject. I have heard lectures by the major excavators of the site, and they would agree. Unfortunately, due to the sensitive nature, some of this is unpublished or in the process of publication. Most of the published research is by Schwartz, who was removed from the project by the directors for producing inconsistent results with age distribution of the remains, and generally poor scholarship, but he took his data with him and continues to publish, for better or worse.\n\nSome sources:\n\n Paolo Xella, Josephine Quinn, Valentina Melchiorri and Peter van Dommelen (2013). Cemetery or sacrifice? Infant burials at the Carthage Tophet. Antiquity, 87, pp 1199-1207. \n\nPatricia Smith, Lawrence E. Stager, Joseph A. Greene and Gal Avishai. Age estimations attest to infant sacrifice at the Carthage Tophet. Archaeology. Volume: 87 Number: 338 Page: 1191–1199. "
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zjoj3 | Scissors' effect on a molecular level | When I use scissors to cut a piece of paper, do the scissors sever the bonds between atoms in the constituent molecules, or does the edge just push itself between the molecules? | askscience | http://www.reddit.com/r/askscience/comments/zjoj3/scissors_effect_on_a_molecular_level/ | {
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3mgf5v | How socially liberal was the Middle East before Wahhabism? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3mgf5v/how_socially_liberal_was_the_middle_east_before/ | {
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"You're making the assumption that Wahabism is widely spread across the middle east. It is not, and it never was. It has always been a Saudi phenomenon, and even then not all Saudi citizens are Wahabists. The movement was founded in the Nejd region of Saudi Arabia; Bahrain (eastern Arabia) is Shiite and the Hedjaz was Hanafi for a very long time under the Ottoman empire. Wahabism has always been intristicly tied to the Saudi royal family since the movement's inception, it was never a populist ideology. ",
"I think OP is assuming that Wahhabism is spread all over the Middle East and that is what people from other parts of the world think of when they think of human rights violations in that part of the world.\n\n_URL_0_ Check out the Wiki for a bunch of threads that might be closer to what you want to know",
"You ask a pretty broad question, and as /u/Blaze86420 notes, a somewhat inaccurate one. The answer is pretty much \"it depends\". For example, the Nasrid dynasty in Spain could be seen as pretty liberal, as well as the Cordoba Caliphate, while the Almoravids adhered to a much stricter interpretation of Islam. The Ottoman empire was relatively religiously tolerant, although certain Ottoman rulers like Mehmed II voiced their desire to eradicate Christianity. Sources by Hungarian slaves in the Ottoman Empire talk about how repressed women were (not much different to modern Saudi Arabia), while other European sources say that women were relatively free and even discussed how the Ottoman treatment of women was progressive.\n\nAlso, the word \"liberal\" is a bit of a misleading word. When I say these countries are \"liberal,\" they certainly aren't the modern US or UK, but rather I'm comparing them to medieval contemporaries in Europe and the Middle East.",
"If I am assuming correctly, what you want to know is how socially liberal parts of the Middle East were in the 20th century, which is much easier to answer. Like other posters have stated, Wahabism is a Saudi creation and had not spread much beyond its borders. However, religious adherence among Muslims in the Middle East was affected in several ways in the 20th century.\n\nThe first issue that needs to be covered is the size of the peasantry in the Middle East. Before WWII, the peasantry comprised almost 90% of the population in most nations in the region. For example, in Egypt, the effendi, the middle class, were only about 10% of the population, the landowners were 1-2%, and the peasantry were the rest. As is seen across the world, less well off people are usually more conservative; as was the case with the peasantry. They were usually strict adherents to whatever beliefs they held (Orthodox, Copt, Islam, Judaism, etc). \n\nHowever, the rising middle class of this time had been educated in Europe (depending on the country in either France or England). The returning educated middle class undertook several reforms throughout the region. Starting in literature and art, the middle class wanted to liberalize the culture before the government. Educated literati throughout the region began publishing novels and, most importantly, newspapers. The goal was to rile up the peasantry and utilize them to affect change in the country, which worked. In Egypt, the peasantry were given greater educational opportunities and were becoming more dissenting with colonial rule. After an incident in the Nile Delta that resulted in the deaths of several Egyptians, the movement to release Egypt from British colonial rule succeeded. This put the middle class firmly in charge, though they were offset by the King and the British. \n\nWhile the case example is Egypt, similar circumstances happened in Syria, Iraq, Jordan, etc. With the middle class in charge, the countries social climate drastically changed. Ideas of nationalism, pan-arabism, and others brought with them liberalized reforms that created better working conditions, less religious law, public welfare, education, etc. They were copying the European models from the 19th century and translating them for the Middle East. This was the general trend. \n\nBy the time of the Gamel Abd-el Nasser (1940s & 50s), Egypt and much of the Middle East had a larger middle class with a more educated population and liberal societies. Religious dress was not as popular in the cities, jazz had taken hold as a form of anti-imperialist music, universities were opening up across the region, and a general sense of liberalism and modernization had taken root. \n\nHowever, it wasn't until 1956 that nationalism, the driving force of liberalization in the Middle East up to this point, exploded. The Suez Canal Crisis proved that Britain and France no longer had the pull to dominate in the Middle East, thus Nasser was considered a hero of the Arab people and the third-world. With this new status, Nasser's, basically Egypt's middle class, reforms took hold throughout the region. Public education raised literacy rates, thus allowing for a larger middle class, burgeoning economies, modernization, etc. The hijab was not seen in cities as often as it was 50 years before. People began to secularize for the most part everywhere, following the Turkish/French form of state-sponsored secularism. In Turkey, Ataturk had declared religion to be a private affair and not having a place in the governance of the state. However, where Ataturk differed from most places was how he imposed secularism. To accomplish his goals, Ataturk created a ministry to deal with religion that tightly regulated it and forced it to remain within the home rather than the school or the public forum. \n\nNot much changed between then and 1979. However, it is essential to understand that, for many Arabs, Nasser's dream had failed. Thus, the idea of Pan-arabism was gone and the leading anti-imperialist dissenter was gone. A hole needed to be filled. In 1979, it was, when the Ayatollah with his own forces along with Marxist forces rose up and ousted the Shah. In a quick turn-around, the Ayatollah then ousted the Marxists as well, leaving Iran as an authoritarian theocracy. This served as a beacon for many people who were in tough times in the Middle East and had lost their hero, Nasser. Iran fulfilled this role to a certain extant. While people did not see Iran as a fellow in a cultural sense (Iran was persian, not Arab), they had successfully ousted the foreign powers that were controlling them. \n\nAfter 1979, many nations in the Middle East experienced an Islamic revival with a more conservative understanding of it. Turkey found itself with large populations of people dissenting against Ankara for its incredibly secular structure; people wanted more places of worship and less restrictions, but Ankara was less than willing. The same happened in the Egypt and Jordan where the Muslim Brotherhood gained a multitude of followers after the Iranian Revolution. The Muslim Brotherhood soon became a huge threat to national security in Egypt until Mubarak began to negotiate with them. The trend was clear. More people were following a more conservative form of Islam and were upset that their countries' governing structures were not allowing it due to their harsh forms of secularism. More people began attending religious schools rather than secular ones (especially among the poor), people began to don religious dress once again, and Islamic traditions were more strictly followed.\n\nNow there is a lot more factors that feed into this, but the 1979 revolution played a huge role in the development of religion place in today's Middle East.\n\nEDIT: Just as a note, after 1979, the Middle East didn't regress. It continued to progress in all sectors of society, but there was an increasingly conservative trend in many countries except a few.",
"I think a better question would be: How liberal Saudi(Arabia) was before the Wahabist movement?",
"So, the \"classical liberal\" position is a system guaranteeing individual rights (you can see how the non-radical left in America is traditionally called \"[social] liberals\" and the pro-business right in much of the rest of the world is called \"[economic] liberals\" despite very different positions today). Today, we think of progressive political movements spreading democracy around the world--that's our metric of political rights. However, in the 19th and early 20th century the measure was much more about constitutional rights rather than voting.\n\nBefore World War 1 in the Middle East, there were two big constitutional movements corresponding to the two big empires. The Constitutional Movement in the Ottoman Empire first achieved success in 1876, though tragically the [First Constitutional Period](_URL_3_) only lasted until 1878, when the Empire returned to absolutism. Nader Sohrabi (convincingly) argues that the Russo-Japanese War (1904-1905) gave a big kick in the pants to constitutionalist movements around the world. Here, for maybe the first time, we see a modern, non-European state decisively defeat a modern, European state. Political liberals pointed out that Japan had a constitution and the modern system worked well, and Russia had no constitution and was incredibly backwards. This helped lead, Sohrabi argues, to a \"wave\" of constitutionalism.\n\nTwo of the most important parts of this wave were in the Ottoman Empire and the Qajar (Iranian) Empire. In 1905, protests broke out in Iran that eventually worked up into the Iranian Constitutional movement. The 1906 constitution, I believe, held until the end of the Qajar Empire in 1925 (when Reza Shah took over in a British-assisted coup). Similarly, the Young Turk movement ended Ottoman absolutism. Almost immediately after coming to power, they restored the 1876 constitution and ushered in the [Second Constitutional Period](_URL_0_) which also lasted until the end of the Empire.\n\nBoth the regimes that came after the Empires were politically High Modernist, prizing things like women's rights, secularism, secular education, industrialization, etc. Many of the regimes that took over the colonized parts of the former Ottoman Empire (both the post-War 1 mandates, and the parts of North Africa colonized by the French) once they became fully independent, generally in the 50's and 60's. Tunisia, Egypt, Syria in particular seem to have followed this high modernist models. These were \"socially liberal\", but were generally not politically liberal. Most have had interruptions of political rights and free and fair elections, but in different proportions. Turkey has had the best record, having elections consistently since 1950 but military interruptions in 1960, 1971, 1980, and sort of 1997. Egypt likely has had the worst record (in terms of elections). Iran has obviously had a period of free elections, a period where foreign powers helped reimpose a monarchy, and the post-1979 period of elections-with-theocratic-rule. Most of the free and semi-free regimes generally tolerated social freedom in the cities (if not political dissent) but meddled less with the socially conservative countryside (which made up the majority of the population). Generally, the social conservatism that existed in these societies, especially pre- the 1979 Islamic Revolution (several other regimes, from Sadat to Saddam to democratic movements in Turkey have tried to use politicized Islam to increase their legitimacy), was society-driven, rather than state-driven. Leaders like Bourguiba in Tunisia, Atatürk in Turkey, and Nasser in Egypt tried to lead their countries into a socially progressive if not politically free \"secular modernity\" (Bourguiba famously would eat on television during the Ramadan fast). Part of their legitimacy was due to thinks like pushing women's rights. In those countries, the state was really pushing what we associate with social liberalism (but, again, not necessarily political liberalism) on to their populations (the populations *generally* responded well to this; again, more in the cities than the countryside).\n\nWahhabism is associated with the Saudi States (the current Saudi Arabia is actually the *third* Saudi state). Saudi Arabia, and the Arabia peninsula generally, has none of the \"core countries\"' traditions of political liberalism or social liberalism. Saudi Arabia is today one of the very few countries that doesn't have a constitution. Wahhabism, or even Salafism, have limited influence outside of the Arabian Peninsula. Movements calling for a theocratic, Qom-like *Vali-ye faqih*-style political order is similarly not particularly prominent in the Shi'a world outside of Iran.\n\nSo if we mean the Middle East as a whole, Wahhabism isn't very influential and political liberalism has a long history. There is, however, a long and mixed history of social and political liberalism, particularly in the cities. This started to change in some places in the 1970's and 80's, often in response to Islam-influenced movements (all the major movements in Palestine were left-nationalist until the 1980's, for example; electoral Islamist parties started in the 70's and became important only in the 80's in Turkey; the Muslim Brotherhood started really leading social change in the 1970's in Egypt, though they're a much older movement, etc.). These movements are not necessarily illiberal, and in fact most studies have found that Islamist movements are increasingly liberal (see for example, [Kurtzman and Naqvi](_URL_4_), or [Tezcür](_URL_1_)). If we mean the Arabian peninsula where Wahhabi-style Salafism is influential, there isn't a significant history of political or social liberalism. You might be interested in the article \"[No Saudi Spring](_URL_2_)\", which does deal with both recent events and the general structure of political life in Saudi Arabia."
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"https://en.wikipedia.org/wiki/Second_Constitutional_Era",
"http://utpress.utexas.edu/index.php/books/tezmus",
"http://bostonreview.net/madawi-al-rasheed-arab-spring-saudi-arabia",
"https://en.wikipedia.org/wiki/First_Constitutional_Era",
"http://www.journalofdemocracy.org/articles-files/gratis/Kurzman-21-2.pdf"
]
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||
2f1yak | what does this joke mean? i've been staring at it and i just don't understand it. | I was told at the doctor’s office that I should get a facelift. The doctor agreed with the waiting room when he came out.
[From this, the second bullet point](_URL_0_)
Maybe something to do with how bad the doctor's eyesight is? I don't see how that would be self-deprecating... | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2f1yak/eli5_what_does_this_joke_mean_ive_been_staring_at/ | {
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"The doctor is supposed to be objective and not influenced by personal opinion/judgement when dealing with patients. The fact that the doctor, whose duty is to the patient's care and wellbeing, joined the waiting room group in belittling the protagonist is where the self-deprecating part comes into play. "
]
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3fqi5q | when a sound or person wakes you up while dreaming, is it just me or is the noise always perfectly timed with an event in the dream? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3fqi5q/eli5_when_a_sound_or_person_wakes_you_up_while/ | {
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"Memory of what happened in dreams is quite inaccurate. Your brain can actually construct the memory afterward, for example showing you that something happened simultaneously that didn't.",
"Your dream may have ended at that point many minutes before you were woken up, you just have no memories of the intervening time and to you the events were simultaneous.\n\nSame things happening when you find yourself always waking up at the \"good bit\" of a dream.",
"According to a psych course I took in university, dreams occur when information is transfered from short term memory to long term memory. During that transfer the brain sees that information, it doesn't make sense as it is just a bunch of random images and gets confused. To avoid confusion it makes up a story and presents it to you as a dream. \n\nI would imagine this would work for external stimuli as well - brain hears a noise, incorporates it into the dream."
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543osu | what did wells fargo do? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/543osu/eli5_what_did_wells_fargo_do/ | {
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"Imagine you went to the bank to open a checking account and the banker tried everything possible to get you to sign up for a credit card and maybe even a second checking account to \"help you manage your finances\" but you just kept saying no. \n\nAfter you left the bank, the banker opened those accounts anyways and just never told you about them. But what about all the fees? WF employees then created transactions moving money between those fake accounts so the fees would be waived. In some cases where bankers got promoted, lost access to accounts, or were terminated, account holders then got late fees, overdraft charges, monthly fees or other penalties on accounts they never knew they had.\n\n• Opened deposit accounts and transferred funds without customer authorization, sometimes resulting in insufficient funds fees for customers.\n\n• Applied for credit card accounts without consumers' knowledge or consent. Customers were hit with annual fees, in addition to finance and interest charges and late fees for some consumers.\n\n• Issued and activated debit cards, creating PINs for customers, without their consent.\n\n•Created phony email addresses to enroll consumers in online-banking services."
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1whscs | What were some common phobias throughout history that don't exist today? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1whscs/what_were_some_common_phobias_throughout_history/ | {
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"I wouldn't call it common, as there's only a handful of well documented cases in the literature and much of the other evidence for its prevalence is anecdotal, but I'll mention it because it's wonderfully weird... \n\nFrom the 15th to the 17th century in Europe wealthy and educated people were struck with [glass delusion](_URL_1_) the belief that one is literally made of glass, or another fragile material such as porcelain, and therefore that one is at risk of shattering. \n\nThe most famous case was that of Princess Alexandra of Bavaria, who purportedly believed she had swallowed a glass Piano as a child and so insisted on walking through doorways sideways so as not to get stuck. Her case and the history of the delusion is discussed in this Stuff You Missed in History Class [Podcast](_URL_0_) \n\nAs discussed in the episode whether this was a genuine Phobia is a contested point - it was described as a 'scholars malady' that is to say a condition that people tended to self diagnose with after they heard that someone they regard as prestigious had it. \n\n",
"while not entirely a phobia since I would think that it implies an irrational fear, the fear of being buried alive, which still happens nowadays albeit rarely, was pretty much in vogue in the 19th century. \nIt got to a point where people would actually install bells that would be above their graves and connected through a tube in their coffins so, where they to woke up, they could ring it and thus be rescued. \n_URL_0_\n\nIn Japan victims of Fugu would lay next to their coffins for 3 days out of fear they where actually paralyzed not really dead, so this was done to avoid cremating them alive. \n\nIn One Hundred Years of Solitude, based largely on Colombian folklore, one of the main characters asks to be decapitated before being buried out of the same fear. "
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7id8bi | why is it that you are able to start a manual car by popping the clutch in second gear? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7id8bi/eli5_why_is_it_that_you_are_able_to_start_a/ | {
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"No-one is really addressing the *why* portion.\n\nIn short there are several ways to ignite fuel. One is by a spark, another other is by compressing the fuel/air mix. Boyle's law tells us that when you compress a gas the temperature increases. If you compress the fuel/air mix enough it will ignite, just as though the spark-plug had ignited it (this is how [fire pistons](_URL_0_) work for starting campfires).\n\nIt works because if the car is in gear there is a direct link from the crank that the pistons turn to the wheels. Normally the pistons fire, turn the crank, the engine, the driveshaft, and eventually the wheels. As long as the vehicle is in gear this process works in reverse too. This is why you downshift when going down a steep hill, you are bleeding speed off by making the wheels turn the engine.\n\nSecond gear (and reverse) have the best gear ratio to start an engine at the speed you can reach by pushing the vehicle.\n\n\n\n"
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1ojjt9 | how can colleges legally create "customized" textbooks and not be found guilty of unlawful monopoly/duopoly? | A monopoly is a company that is the sole producer of a certain good or service. I know that monopolies themselves are not inherently illegal, but can become so when they exhibit certain qualities. For example: price gouging and "refusal to deal".
At my university, the school buys books from Pearson or McGraw hill, then "customizes" them by removing (not adding, no joke) content that doesn't apply to the specific course being taught. Then, the book is sold to the student at a markup over the normal cost of the textbook because it has been customized for your specific course. These textbooks don't add content, homework assignments, extra lecture/professor notes, but they screw with your ability to buy the original publisher textbook because the chapter numbers (and occasionally names) are different.
What makes it even worse, is that the universities refuse to let the students who purchase (or rent) the original publisher textbook or ebook, what the equivalent chapters are in the book.
So how is it that colleges that do this, charge twice as much as the original, and then get away with it without being fined for exclusionary practices and price gouging? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ojjt9/eli5_how_can_colleges_legally_create_customized/ | {
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"Your college isn't the only one offering BIO 101 or whatever the course is. It's not exclusionary because you could have chosen a different college, so they aren't doing anything anti-competitive. It's sort of like how a bank can charge you a fee that no other bank charges, but they get away with it because they can say \"hey you could've picked a different bank.\"\n\nI'm not saying it's right, but that's the loophole that they're dancing around in while they flip you the bird.\n\nedit: by the way, my school is doing the same thing for one of my courses, and what they're doing is they package the lab manual (which you need your own copy of) in with the textbook, so you can't just use a library copy or something. It's highway robbery, but it's legal."
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fftsxg | What exactly are VPN’s and how do they work? | askscience | https://www.reddit.com/r/askscience/comments/fftsxg/what_exactly_are_vpns_and_how_do_they_work/ | {
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"All of your traffic that goes to the VPN adapter is addressed to the same destination (the VPN gateway). Inside those packets (encrypted) is another packet with the real destination and contents that you want. \n\nThe VPN gateway unencrypts the packet and sends it on its way with a source address that’s part of the network the VPN gateway is in. It does the same for packets headed back to you. \n\nWhat that means is your traffic is (virtually) inside the network that’s behind the VPN gateway. \n\nLet’s say that that network is your home (many home WiFi routers can run a VPN gateway). \n\nIt lets all of your traffic from your laptop that’s away from home get to your home computers without going through the router so things like printer sharing will work without exposing your printer through port sharing etc. It’s as if your laptop was on your home WiFi. \n\nIt’s great for things like being on your work network, when you’re not at work. \n\nSo why do people like them for “security”?\n\nWell, anyone spying on your remote laptop only sees encrypted traffic going to one place (the VPN gateway). It doesn’t know what’s in it, or where it’s going. \n\nThe final destination of your traffic doesn’t have to be within that VPN. It could be intended for _URL_0_. When the traffic gets to that VPN it would be sent out to that server from the VPN and back to you via that VPN. Anyone wanting to charge someone with piracy would only be able to charge the owner of the VPN (who probably lives outside the US). \n\nNobody can connect you to that piracy (unless the owner of the VPN decides to turn over their records).",
"Simply put, a VPN is like a privately run underground train system in a city. \n\nYou enter a station at one point and leave at another, but no one knows where you came from or where you are going, unless they run the underground train system. But they promise really really hard, that they aren't looking or writing anything down.",
"Imagine you have to do everything by mail, and you don't feel safe sending postcards due to your post office being staffed by your overprotective mother. A VPN is like putting the postcard in an envelope to your buddy who is away at college. Your buddy opens the envelope and resends the postcard. He gets a response via postcard and puts it in an envelope back to you.\n\nNow the benefit to avoiding your snooping mother (who is actually an ISP) is obvious, but you often hear things like \"Australian Nexflix has that show, sucks to be in Canada.\" If your buddy (who is the VPN endpoint) is in Australia, how does Netflix know? As far as they're concerned, they're sending stuff to an Australian address.\n\nAs to how it works, it's mainly software in your PC or your router that's signed up for a service that encrypts traffic and sends it to the designated endpoint. One of the less talked about applications is very common in remote work - Companies set up VPNs so you can connect to all the internal tools as though you're on the company network by setting up endpoints within the company firewall.",
"The diagrams below are an oversimplification of TCP/IP and IPSec, to get the point across without going too far into the weeds about the details.\n\nA VPN is designed to prevent anyone between two computers from being able to inspect the information being sent between the two computers. \n\nAs for how it works, we can look at an example of non-vpn traffic and compare it to vpn traffic. The data your computer sends over the internet is sent in chunks called packets. A normal TCP/IP packet looks like this\n\n |------|------|--------------|\n | IP | TCP | Data |\n |------|------|--------------|\n\nIP contains the source and destination IP. TCP contains the source and destination Port information. Data contains the data being sent to the destination IP. \n\nAnyone, such as an ISP, with access to this packet can read it an know what server you are sending information, as well as the information itself. You can protect the data you are sending using HTTPS, which will encrypt the Data portion of the packet using Transport Layer Security (TPS). But this just encrypts the data, not the source and destination TCP/IP information. So someone might know you're visiting a banking website, but won't be able to read whatever data is being sent, like your account password or balance or whatever other information is being sent. \n\nHowever, HTTPS doesn't obscure the TCP/IP information, so someone can still figure out your browsing habits if they really wanted to. \n\nVPNs go an extra step by taking the entire original packet, encrypting it, and wrapping it in another new packet with different destination information. Like so:\n\n |--- Encrypted ---|\n |-- Original Packet --|\n |------|------|------|------|--------------|---------|----------| \n | New | ESP | IP | TCP | Data | ESP | ESP Auth |\n | IP |Header| | | | Trailer | Trailer |\n |------|------|------|------|--------------|---------|----------|\n\n\n\nYou can see the original packet is still there, surrounded by new parts. VPN software using ESP, Encapsulating Security Payload, to encapsulate the original packet to protect it from eavesdroppers. This new packet is not sent to the original destination IP, but to an intermediate VPN device. The packet is protected while enroute to the new VPN IP. Once it reaches the VPN endpoint, the endpoint unpackages and decrypts the original packet, overwrites the source information with its own information, and then sends it along to the original destination. Anyone listening would find it exceedingly difficult to discover the true origin of this packet. \n\nThe VPN endpoint will also do the same thing in reverse. Once the packet reaches its destination server, the server will respond with data, sending it to the VPN endpoint. As far as the destination is concerned, the VPN _is_ the originator of the packet. The VPN will then encapsulate and encrypt the return packet, and send it back to your device. \n\n\nThis is useful for a lot of different things. Businesses can use it to securely share a file server to remote locations without exposing the file server traffic to the public internet, for instance. If you have to routers set up with a VPN tunnel between them, then the devices on either end of that tunnel wouldn't even necessarily be aware that they weren't on the same internal network and were actually traversing other networks."
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1fgrwi | if we die after roughly 3 weeks without eating, why do eat 3 times a day? | I know you wouldn't spend 3 weeks very wealthy or you would lack energy, but still, it seems it's some sort of waste. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1fgrwi/eli5_if_we_die_after_roughly_3_weeks_without/ | {
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"Eating three times a day is actually a modern invention (modern in terms of human history as a species). It wasn’t uncommon, or even unhealthy to eat once a day, or sometimes skip a day every few days. It still isn’t unhealthy to do that today, you are just so used to eating three times a day that it would be difficult.\n\nWe die after 3 weeks of not eating because we are healthy and well nourished. If you ate rarely and were malnourished you would die much quicker. We eat daily to make sure we are in top health.\n",
"Our body stores enough fuel to keep going for a while, but regular meals allow us to keep those reserves stable. Over the course of starvation your body dramatically cuts back energy use as well; if we were flirting with starvation we would be weak, stupid, slow to heal if at all, and generally unfit for anything.",
"Broke college kid here, I've eaten only once or twice a day pretty much all year. Haven't noticed any difference.\n\nBreakfast is a scam. ",
"Firstly, as others have said, three meals a day is a modern thing people in wealthy countries do. A lot of people are lucky to get one good meal in a day, that's why we've evolved to survive so long without food.\n\nNow, you would never want to go three weeks without food. Even two weeks would inflict a terrible toll. The first thing to go is your body fat, as you'd expect. When you start running out of fat, your body starts breaking down your muscles. You'd completely lose any energy and just feel like sleeping all the time. If you ever reach that point you're in serious danger because you can very easily pass the point of no return. That is to say, you can get into a situation where you totally lack the energy or ability to feed yourself. Days could go by in slumber as your body eats itself. By this point your ability to digest food would also be compromised - we use lots of energy breaking our food down - and eating solid food would be impossible. You'd most likely vomit it back up assuming you could swallow it in the first place; if you kept it down it would most likely constipate you.\n\nAfter you've the majority of your body fat and muscles, your body would then turn to all the other soft organs in your body. That means your liver, kidneys, pancreas, and your brain. Nerve cells are largely made up of fatty acids and are therefore full of energy. As your body breaks down your brain, it's possible to experience irreversible brain damage that causes significant defects in learning, memory, and perception. Anyone experiencing in this condition needs to be admitted to hospital, as not only are they likely to be a danger to themselves due to not knowing what's going on around them, they're also at risk of sudden heart failure. By this point levels of potassium are likely to be extremely low, and we need potassium to send signals down our nerves. This is a common killer in acute anorexia; the signal literally stops going to the heart and boom, they're dead.\n\nI've seen someone go down to just under four stone due to a combination of anorexia and bulimia, and that's pretty much what happened. You wouldn't believe what the body does to keep itself alive; it will even sacrifice the person inside. So, don't starve yourself. It's best to eat reasonable, healthy meals on a regular schedule. ",
"Three a day isn't really a rule, but a certain amount of nutrition is needed to 'keep ahead' of what's needed.\n\nThink of it this way... your body is a chemical furnace. Picture a steam boat. You need to keep throwing logs on the fire or it will go out. If you run out of logs, you can start taking apart the boat... stuff you can live without first, like some stairs, a few chairs, and so on. As time goes on you start getting down to more and more important stuff that doesn't burn as well, but you're desperate... the rudder, the floor... and as you cannibalize your boat it eventually just falls apart.\n\n... (gets less ELI5 from here. To an actual 5 year old, I'd probably stop with that)...\n\nNormally, you have a reserve of logs (fat) sitting along the side of the boat. Your body likes to avoid using this reserve because it's designed to be a backup source of energy. And when you do use it up, it wants to replace it as soon as possible (brings diet issues into focus a bit, eh?), because your body is built to survive emergency shortages.\n\nAdd to this complication that it's not *literally* a fire... you need specific \"Types of Wood\" if you will. So while you can work off the backup fuel, it's not as good for you (and it doesn't \"burn as hot\"... the energy doesn't work as efficiently as things like glucose/sugar).\n\nAnd, to throw on more unnecessary information and walk farther away from a true ELI5 response, add to the complication that certain body parts, like your brain, require certain fuels... such as your brain which really only uses glucose as fuel (part of what makes unmonitored blood sugar in diabetics so dangerous).\n\n",
"If my car can drive for fifty thousand miles without an oil change before it's totally ruined, why do I change the oil every three or four thousand?",
"Surviving is not the same as living. That said, I eat a banana for breakfast skip lunch, and then eat meat and veggies for dinner. Think of how inactive most of us are, sleep, stand get dressed, sit in car/train, stand to walk in to job, sit for four hours, stand to go to cafeteria, sit to eat, stand to go back to office, sit for four hours, stand to get to train car, sit to go home, stand to go inside make dinner, sit to eat dinner, sit to watch tv unwind, lay down to sleep, repeat. "
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3oo9yd | How much 'real time control' did pre-20th century generals have over the battlefield? | Generally speaking, how much of an army's victory relied on pre battle planning versus immediate real time decisions by the highest ranking officers? (I realize this would obviously vary depending on the commander.)
I'm in a mechanized infantry unit in the US National Guard, and my Company Commander has a LOT of tools to keep control of the battlefield. The Bradley's are all equipped with Blue Force Tracker, most of the dismount squads have radios, and we have a Raven that can fly over and show a live feed of the AO.
I was a squad RTO during our last series of wargames, so I had a proverbial front row seat to the initial battle plans and their execution. Even with the live feeds and instant communication, the initial battle plan ALWAYS has to be heavily modified on the go by the Lieutenants and NCO's. And in the confusion of a simple wargame with lasers instead of real bullets, it gets confusing and chaotic. My current CO said that it's like 'boxing blind.'
How the hell did generals maintain control of their armies with just scouts gathering intel and couriers to disseminate orders?
tl;dr: War is f****** chaotic, how did pre-20th century generals retain accurate intel and maintain control over their hosts of men without modern technology? Did they even really have much control beyond the initial battle plan and where to send reserves?
UPDATE: A huge thank you for all of this information! I apologize for not responding sooner, I haven't had access to a computer this last week. | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3oo9yd/how_much_real_time_control_did_pre20th_century/ | {
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"Depends on when and where. Pre-20th century, after-all, covers over 2500 years. While I've not read anything explicitly stating it, it seems to me command style changed with the size of the army and battlefields.\n\nIn Classical Greece, commanders could basically only lay out a battle plan before it starts. Once all the sub-commanders have their orders and the battle starts, there's nearly no control whatsoever. This is due to the fact that the general fought as a hoplite on the front lines. So it was very hard for him to know what's going on and issue new orders. The best he can do is guide his own detachment according to the pre-set plans. With battlefields being relatively small in size and usually no reserves to speak of, it didn't really matter that much I suppose.\n\nJust prior to Alexander, generals on horseback began to appear in Greece. But they still very much fought on the front with the cavalry. So they had more control and could respond better to situations around the battlefield and far more quickly. Alexander at Gaugamela is a well known example, but I like Pelopidas responding to battlefield situations at Cynocephelae even better.\n\nThe successor states probably eventually adopted having the commander and his bodyguard cavalry sit in reserve, so he's busy commanding instead of busy fighting. And this way he knew where to send the reserves because watching from slightly behind the lines. If the successor states didn't do it, certainly by the Roman Empires that's what was done.\n\nIt's not all that linear though. For example at Hastings long after the fall of the Western Empire when armies were smaller again, Harold was on foot in line with his housecarls, similar to the hoplite style, with no control over what his brothers did with their contingents. William on the other side fought with his Norman cavalry (though I'm not sure if he was in reserve or not, it seems he was pretty active). He had to take off his helmet to show everyone he was still alive at a point in the battle, and led a few attacks.\n\nThere are other variations too. Supposedly Mongols like to set up their commands on a hilltop instead of with the army and issue orders with horns, drums, flags, signal arrows, etc (forgot which book I read that in, was it *Genghis Khan and the Making of the Modern World*?) Similarly, by late Sengoku the Japanese prefer to place the commanding general and his personal troops on a hilltop slightly behind the fighting where he can see what's going on and issue command to move forward. And on the other side of the world this was also done in European battles such as Naseby, as both King Charles and Fairfax were slightly behind the battle on top of ridges, though Charles apparently didn't commit until it was too late, so ended up not committing at all.\n\nBy the 19th century (at the latest) army sizes and battlefield had grown so large that it was very difficult (or impossible) for the commanding general to see the entire battlefield. So a lot of time the general have to act on reports of aides and messengers. Since messages travelled at the speed of a horse, and you aren't seeing it with your own eyes, it could get pretty confusing. See examples in this thread.",
"Bear in mind that it would be much easier to control your forces pre-gunpowder era than later, and with smaller army sizes. A battlefield with cannon and musket fire echoing across it would be much harder to communicate with, say, horns or drums, in comparison to if these horns were used in a pre-gunpowder era battle. Similarly, with smaller army sizes, you'd have less of a problem conveying messages from one side to the other, and overall you'd be able to keep an eye on the entire unfolding. In terms of \"real time control\", you also have to account for the delay between messengers getting messages across, where they could be delayed by opposing forces, or simply due to the time taken to traverse the field on horse or by foot. A basic battle plan would be in place but, as all battles go, would probably be modified as it progressed - you'd have a rough formation idea at the beginning, as well as certain rules for engagement/retreat, however it also relied on the best judgement of the commanding officer (who would relay his commands down through the hierarchy) or, if he wasn't available, the next person down, and so on.",
"An interesting case study in the real-time control of the battlefield is the famous Charge of the Light Brigade. \n\nThe British commander was Lord Raglan, who was standing on top of a hill and able to see the whole battlefield. In front of him, at one end of a long valley was his brigade of Light Cavalry. At the other end of the valley was a well-defended enemy Russian artillery battery. \n\nBehind Lord Raglan one of the Russians' other artillery batteries was in retreat. Raglan wanted to order the Light Cavalry Brigade to chase after them and seize their artillery. With no radio, he had to send a runner with a note which read *Lord Raglan wishes the cavalry to advance rapidly to the front, follow the enemy, and try to prevent the enemy carrying away the guns. Troop horse artillery may accompany. French cavalry is on your left. Immediate.*. This was accompanied with a verbal order to attack immediately. \n\nNow there was a crucial mistake would not have occurred with modern technology. The Light Brigade only had knowledge of one Russian artillery unit, the well-defended one at the other end of the valley they were standing in. The Brigade set off down the valley. The runner suddenly realised the mistake, and chased after them to redirect them, but was shot down by the Russians. There was no mechanism to contact the unit and call them back. The Brigade did successfully and bravely seize the artillery but were surrounded and taken out by other Russian units. \n\nLucan, the commander of the cavalry, later claimed that he had asked the runner which guns were being referred to and the runner had unhelpfully swept his arm across the whole battlefield, where only those at the end of the valley were visible.",
"There is a lot to this question, and answers will vary considerably depending on the era and the army. In the Napoleonic era, generals had their ADCs on horseback, typically in a \"string\" taking turns making runs out to relay orders to individual units. Aides were typically very trusted appointees who were part of the General's \"military family\" or retinue and very often a son or son-in-law, so in some respects they were expected to know very intimately what a general was thinking. They were often entrusted with scouting missions-- for instance, a Corps commander would send a staff colonel off with a fighting patrol of a squadron or two of light cavalry to take prisoners and see what he could stir up. On a lower level, a brigade commander could put his ADC, a captain, in charge of a light company and two grenadier companies from one of his regiments and have them overrun a troublesome artillery battery. Both these examples come from Col. H.C.B. Rogers, \"Napoleon's Army\" (1982), which has a rare couple of case studies of Napoleonic battles on a small scale. The memoirs of Baron Marbot also contain a lot of info about the role of an aide and light cavalry officer. The system relied on the skill and initiative of subordinates as well as the ability of a senior officer such as a army or corps commander to assume direct control over a developing situation. It helped that armies were relatively small and fought in small areas compared with 20th century armies. As Napoleonic armies swelled ever larger with masses of conscripts, and the best of the generals were killed off one by one, command and control grew more difficult and the tactics devolved into bludgeoning contests like Borodino or Wagram. For a details of how a battle plan could get entirely too elaborate for green troops and inexperienced officers to follow, \"the War of 1812 in the Old Northwest\" by Alec Gilpin (or most other accounts of that conflict) have plenty of examples. One case in particular is the Battle of the Rapids which occurred during the siege of Fort Meigs on May 5, 1813. I could write a detailed account but the basic details are available in plenty of sources in print or online. It illustrates perfectly what could happen when a commander lost command and control during a battle taking place over a wide, wooded area--and General Harrison was a professional soldier who had been schooled as an ADC for General Anthony Wayne fighting over the very same area. Basically, once a situation was developed it came down to the initiative of field officers to react or rally their units. Militia officers and their men weren't necessarily bad troops, but they had to be kept close in hand or risk disaster. Generals could affect a situation if they were able to gallop into the midst of a battle and rally or coordinate troops, but they ran the risk of getting shot, which frequently changed the game if their subordinate was not as energetic or skilled as they.",
"My are is First World War and just before, which isn't *technically* within the scope of your answer, but I'll go ahead and answer anyways because I think you might find the answer helpful.\n\nFirst, let's pick apart your question a little bit, because I think that in doing so, we can start to see some of the ways in which battle and the concept of \"a battle\" had changed and was still changing by 1914. How much real time control a commander involves two things, in my estimation: a) the ability to get accurate information regarding the course of battle at any given moment and b) his ability to relay to combat forces his commands. The fulfillment of one of these conditions does not necessarily mean the second is automatically fulfilled. On the other hand, both are closely related and often rely on the same technologies, or lack thereof.\n\nMoving on, some people in the thread have mentioned that the answer depends, based on what period we're talking about. This is obviously true, but it also depends hugely on what level of army organization you're looking at. /u/ParallelPain answered with regards to a Classical Greek battle, where you could theoretically watch the entire battle from a high enough vantage point. One of the biggest trends in nineteenth century military history is the expansion of armies with mass conscription and states with the organizational and material wealth necessary for fielding armies of millions. By the outbreak of the First World War, we've got not only regiments (the basic unit of infantry armed strength), but also divisions (which unite infantry strength with artillery and cavalry force, as well as logistical support), but also corps, armies, and even army fronts comprising two or more armies.\n\nThis also forces us to acknowledge that by the 20th century and the First World War, even the concept of a \"battle\" has to be looked at and played with a little bit. Going back to Greece, a battle might last a few hours. Skipping over quite a few centuries of military history, by Gettysburg we have a three day battle. But these are still unquestionably 'battles.' By 1914, we see weeklong engagements like Tannenberg, the Marne and Komarow. These single 'battles' are titanic when compared to single-day infantry clashes in Classical Greece. In fact, these 'battles' may be more accurately described as a vast network of smaller battles all being fought with regards to a single operational objective, e.g. \"capturing X town.\" Then we have Verdun and (moving forward) things like Stalingrad, which challenge the conception of a 'battle' as a unit of analysis even further. \n\nAll this was a very roundabout way of saying that commanders at different levels are going to have different means for a) observation and b) control based on the number of men (and cavalry detachments, artillery batteries, and supply columns) they're commanding and the geographical and temporal scope of the 'battle' they're overseeing.\n\nI focus on the Austro-Hungarian Army, so we'll use them as an example. Each turn of the century army had its institutional peculiarities, but *roughly*, this should suffice in general. I'd love for people more knowledgeable about specific armies to chime in and provide some context. \n\nNow for the actual answer. Let's start at the top. The truth is, radio and telephone communication at the outbreak of the First World War were nascent technologies and their application to ground combat was still being figured out. But with the larger units of organization - armies, corps, divisions and even regiments - the telephone and telegraph were being used quite well by the Austrian Army. In 1914, each division had its own signals detachment, armed with a portable telegraph set and several kilometers of telegraph/telephone wire that could be unrolled and laid at the will of the commanding officer. Communications travelling from division commands up to corps and army headquarters were quite regular. The Austrian Army meticulously (by necessity) recorded a lot of information on each telegraph: when the message was sent, where it was sent from, which command was sending it and to whom, but also when it was received, when it was read, by whom it was read and to whom it was passed along. These messages varied in the level of detail, but the most common message was a \"Disposition\" and sought to give the corps or army headquarters where the division and its constituent regiments were located and what they were doing. For example, a telegraph I have a facsimile of from the Vienna War Archives reads, \"have arrived in the Cossack barracks [in the town of Zamosc]... and captured assorted war material, including a munitions wagon, 2 portable kitchens, as well as 2 guns on the road towards Lubelskie.\" This was sent from a divisional commander to his corps commander and is typical of the type of communication being sent up the chain. As you can see, this message and others like it leave a lot to be desired. Telegrams were also being sent down the chain of command, with corps commanders telling divisional commanders where their neighboring units were, how their mission objectives were progressing and whether enemy activity had been reported in their sectors. These telegrams were essentially aimed at giving commanders an idea of where forces were on the battlefield and what they were doing. Divisional and corps commanders also relied on hand-drawn dispositional sketches showing where units were with regards to certain objectives and landmarks. What these sketches made up for in detail that telegrams couldn't convey, they lacked in speed. Maps had to be ridden (by bicycle, horse or car) to the pertinent headquarters. This could take anywhere from ten minutes to several hours depending on the state of roads, how well the area was known to the different commands, and the combat and traffic situation of those roads.\n\nThis has all so far been about how commanders got information on where their troops were. As you can see, it would take a powerful intellect with massive amounts of training to put together a cogent picture of what was going on. In engagements which were lasting several days to a week, the time constraint was, as with all combat, very important, but commanders could usually get a telegraph message from a subordinate within an hour, from the moment the subordinate decided to send the message to the moment a transcribed message was handed to the superior officer. This, combined with illustrated disposition maps and the spoken word of messengers, was no Blue Force Tracker, but it worked reasonably well.\n\nAs for sending commands and trying to affect the flow of battle, commanders relied on the same sorts of technologies. Written commands were transferred via telegraph to subordinates in the same way dispositions were reported going the other direction. For example, one telegram I have from II Korps to 13th Division command tells that commander: \"both infantry brigades, the artillery brigade and artillery HQ are to immediately assume a disposition on the northern egress road from Zamosc and to establish connections with 25th Infantry Division.\" Like reports being sent up the ladder, commands being sent down the ladder could be expected to be read by the pertinent subordinates within an hour.\n\nThe telegraph I chose helps me segue into the next issue, that is, sub-divisional commands and reporting. By 1918, individual regiments would be armed with telegraph units and plugged into the communications network, but in 1914, all communications at the sub-division level (regiment and battalion) were done on paper or by messenger. The Vienna War Archives is literally full of these tiny bits of paper, about three inches by five inches, with written dispatches on them. The blank dispatch cards were printed en masse in perforated card books so that the officers using them could save time by plugging in the information into pre-printed spaces. In typical Habsburg bureaucratic function, there are spaces for every bit of pertinent information: sender, receiver, time sent, date sent, area sent from, etc. Speaking to the paramountcy of the horse and rider to sub-divisional command is the spot on the dispatch card where the writer is asked to circle one of the following: \"trot\" \"gallop\" or \"trot and gallop.\" These messages took significantly longer to relay, depending on the geographical proximity of the sender and receiver and the intensity of combat in the area. Of course, many messengers went missing, were captured or killed and many messages never received, often resulting in lives lost. Hand-drawn maps were also very important at the sub-divisional level, especially as a means by which regimental commanders showed divisional commanders where their units were located.\n\nFinally, at the very nitty gritty level of sub-regimental command, what we would consider \"combat\", flags, written notes and messengers had to be used. Since radios wouldn't become standard until the Second World War, battalion commanders had to rely largely on flag signalling and messengers to get their commands into the hands of lieutenants. At the beginning of the war, each platoon (60 men or so) had a 3-man signalling section: a patrol leader, an observer and a signaller. The signaller had two flags and used these to relay observations and reports up the chain. At the company-level, the Austrian Army experimented with field telephones even at the beginning of the war, but they were not standard, especially in the context of highly limited financial resources prior to the First World War. These telephones were operated using Morse code and were carried along with about a mile of telephone wire.\n\nSources:\n\nLucas, J.S. *Austro-Hungarian Infantry, 1914-1918.* Almark Publications, 1973.\n\nVienna War Archives, independent research",
"In the Franco-Prussian War the command and control system relied more on the independence of low level commanders on the battlefield, with von Moltke the Elder organizing the larger scale plans of battle. \nThe idea was von Moltke could command the strategic movements of the armies, but allow the lower commanders who fully understood the ground situation to make the tactical decisions."
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2ffwny | Why is it better letting banks loan 10x of bonds they hold (fractional reserve banking), than letting people to spend 10x of bonds they hold? | askscience | http://www.reddit.com/r/askscience/comments/2ffwny/why_is_it_better_letting_banks_loan_10x_of_bonds/ | {
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"The short answer is bank loans are generally supposed to be done in a manner which is controlled, conservative and carrying a large chance of return. Banks also usually have large diversity of revenues streams, which means they are supposed to be relatively stable in the case of minor problems in the markets - neither of these are easy to quantify for a small scale individual.\n\nIts also worth noting that banks can only give you interest by loaning that money away, so even if only loaning the money they have, a bank run still kills them. \n\nThis doesn't exist to anywhere near the same degree in most individuals' general purchases (it also frequently does not exist in banking either for that matter), but there's nothing stopping a wealthy individual with diverse revenue streams setting up as a bank and 'spending' 10x their bonds on loans to people - it all just comes down to what you want to spend the money on and what you have coming in as revenue.\n\n",
"I'm not sure I completely understand your question - in fractional reserve banking, any individual bank doesn't loan 10x the money they receive. They only loan a portion of the money they receive from depositors (90% say). This money is spent by the loan recipients, and (in a developed economy) ultimately ends up redeposited in someone else's account. This process thus happens over and over again. Mathematically, you can calculate that the ultimate economic effect is that the total money spent is 10x the amount that the bank holds in reserves (by adding up .9 + .81 + .729 + ...).\n\nIt's worth noting that each round of this involves individuals spending the money they receive from the bank as a loan. So for example when the bank loans me 100k to buy a house, I get the house and the money goes back into the bank account of the person I bought it from. I'm still on the hook to pay back the bank, just like the bank is still on the hook to give money back to people out of their checking account. This works because not everyone is going to want their money back at once.\nThe bank's job us to keep track of everything, to pick good people to loan to (whether they do a good job at this is a separate discussion), and to provide interest and services so people want to deposit money with them.\n\nAn additional complexity is that the government guarantees many bank accounts. This means that if the bank screws it up (or if everyone simply gets scared and decides to take out all their money and put it under their mattress), the government has promised to find a way to give the money back to people who deposited into the bank. In actuality, even making this promise should prevent them from ever needing to do this on a large scale since it keeps people from freaking out and withdrawing everything. Furthermore, in exchange the banking industry is highly regulated - the fact that banks are required to keep a certain reserve percentage by law is one example of this. These regulations are supposed to insure that banks don't take on excessive risks."
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7yyyiq | the strength of currency | I don't think the "strength" is a exactly what I don't understand, but it's the closest word I could find. I've heard people say that the Euro is better than the USD because it's worth more per unit. This doesn't make sense to me. That's like saying a dollar is better than a cent because a cent is 100x more than a dollar, isn't it? You can easily convert between the two in both cases. Am I missing something? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7yyyiq/eli5_the_strength_of_currency/ | {
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"You're right. It's a common misconception to say, for example, that since you get more Canadian dollars in exchange for US dollars, the US dollar is worth more. If prices were the same in both countries that would be the case, but prices are not even consistent from one city to the next within the same country, let alone across international borders. \n\nOnce US dollar is worth about 1.25 Canadian dollars. If a product that costs $1 in the US costs $1 in Canada, it's cheaper in Canada because the Canadian dollar is worth less, but if the same product that costs $1 in the US costs $1.50 in Canada, it's cheaper in the US because 1.25 is less than 1.50. \n\nThe more accurate metric is how the exchange rate changes. If exchange rate changes from 1 USD = 1.25 USD to 1 USD = 1.1 USD, that means the Canadian dollar is worth more than it used to be, indicating that the Canadian economy is growing faster than the US economy. ",
"It is mostly irrelevant to compare what 1 of one currency is compared to 1 of another. You're right about that.\n\nThe \"strength\" of a currency that I think you're referring to is more of the confidence in it that it will retain its current value - value not meaning how it exchanges to other currencies, but what you can actually purchase with it.\n\nLook at the Venezuelan bolivar as an extreme example of a weak currency. You could be able to afford a car this month and bicycle next month with the same amount of bolivar. ",
"The analogy between dollars/euros and dollars/cents is missing a key point: the cent is defined as 1/100 of a dollar; that number cannot vary (barring an act of Congress, at least).\n\nMeanwhile, a dollar will buy a varying amount of euros over time. Both currencies are fairly stable, so this isn't an enormous swing, but - if you used $1,000 to buy euros three months ago, you would have gotten €849.53. If you were to then exchange that €849.53 back to dollars today, you would receive $1,047.80.\n\nSo the euro, relative to the dollar, has gotten stronger in the last three months - one euro is worth more dollars now than it was then.\n\nThe inherent strength of a currency is a harder concept to nail down, but one way to think about it is in terms of how stable prices are for domestic goods where the currency is used. One of the reasons the US dollar is a strong currency is that prices are relatively stable. If you earn a dollar today, you expect it to be worth pretty much the same (in terms of what you can buy) tomorrow. This means that the dollar serves as a useful store of wealth.\n\nThis, in turn, can be (in part) attributed to the belief that the US government won't suddenly go on a money-creation spree. That is, they won't start creating dollars (by spending) too much faster than they destroy them (by taxing). \n\nIt can also (in part) be attributed to the belief that the US government won't collapse or be torn down - note that perhaps the most basic reason government-issued currency has value is because the government insists you pay your taxes in its currency. This means that you need a ready supply of dollars to pay your US taxes, which means there's a built in demand for dollars in the domestic economy."
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404s7n | why wont an xbox dvd work on a playstation, or computer? | I've been wondering. Movies are able to do this, is it only to make money? It would, however, destroy the whole "console exclusive" thing. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/404s7n/eli5_why_wont_an_xbox_dvd_work_on_a_playstation/ | {
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"its just different hardware. DVD machines are made to be able to be played on multiple different systems (theres sortof a standard), while thats just not the case for console gaming. They have no need to keep a standard so they dont. \n\n > It would, however, destroy the whole \"console exclusive\" thing.\n\nand there you have it. its not in inability, its a choice ",
"Are you talking about the video games on discs? If so, they are Blu-ray now, but that doesn't matter. \n \nYour question is the same as \"Why doesn't this Windows program run on Mac?\", it's because they have different programming. \n \nAll Blu-ray movies can play on all Blu-ray players (not taking into account region coding or anything like that) because all Blu-ray players are programmed to read the same data."
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5nna4m | How much influence had Fake News to cause the Spanish–American War of 1898? | Was public pressure (caused by Yellow Journalism) a major factor into the war being declared? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/5nna4m/how_much_influence_had_fake_news_to_cause_the/ | {
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"I think this is an incredibly complex question, and really one that has gained added depth the further we have gone from the events as more has been learned.\n\nIn particular I want to focus on two areas, the reporting of pre US intervention newspapers from Cuba, and the reaction to the loss of the Maine.\n\nMen working on behalf of Hearst and Pulitzer in particular could be shameless at times in their reporting, such as relating how brutal Spanish police violated the privacy of a young American woman's bedroom and ordered her stripped in the hunt for smuggled messages and money for the rebels. But conversely the war against the Cuban rebels DID take some brutal turns, and for almost a century American interests had been eyeing Cuba while there was a feeling of at least basic support for a local uprising against a backwards colonial holdout. \n\nAnd eyeing it all with both some general support, but also an eye on the bottom line Hearst in response to reports of cooling tensions was quoted as saying to one of his men in Cuba. \n\n > \"You provide me with the photographs, and I'll provide you with the war\"\n\nHowever most evidence suggests this was apocryphal, while Hearst expected a Cuban victory and supported it, the paper was not actively engaged yet in supporting a US participation, nor were tensions particularly cooling at the time. The rebellion was still actively being fought. _URL_1_ \n\nHowever an actual declaration of war in support of the rebels was far from on the table, McKinley was still uninterested in military action, but sought to appease both business interests and Cuban supporters by negotiating with Spain for reforms to bring peace, however that went nowhere in the end. However Spain did recall its Governor General from Havana who had been a good deal harsher than his predecessor, but this then enflamed loyal Cubans as a sign of wavering support and led to agitation in the capital. \n\nIn response the US Consul in Havana, Fitzhugh Lee(nephew of Robert E. Lee and a former CSA cavalry officer), called for a warship to help protect US citizens and property, and thus arrived the USS Maine. 3 weeks into her stay at about 9:30 PM an explosion completely destroyed the battleship and killed 3/4 of her crew. In March a naval inquiry reached the conclusion that the Maine had been sunk by the explosion of a mine. For the weeks following the sinking Hearst and Pullitzer's papers had been demanding blood, while Pulitzer supposedly thought it ridiculous that Spain would try to mine a US warship the fact was the Maine was now sitting in the harbor mud, and Spain was the obvious culprit. Calls for concessions did little to dampen tempers and the blood of the public. While many in government too thought war was the only answer, such as Senator henry Cabot Lodge, and his confidant, Assistant Secretary of the Navy Theodore Roosevelt. Thus with enough support in Congress and a penned in Executive, with a public calling for blood a month after the end of the Maine inquiry, with the caveat that the US would not annex Cuba thanks to the Teller Amendment, in late April the Congress passed a bill authorizing military force by the President to liberate Cuba and war followed a few days later. \n\nThe key here is of course the sinking of the Maine, and calls to \"Remember the Maine\" were echoed around the nation. In years since though there has been a good deal of examination into what actually sank the ship. Most notably was an investigation in the mid 70's by Admiral Hyman G. Rickover. Rickover was a no nonsense, damn near authoritarian, who was almost singlehandedly responsible for the creation and state of the modern nuclear navy even today. And his interest was peaked by the possibility, discounted at the time that a coal fire was responsible for setting of Maine's forward magazine.\n\nHe came to a conclusion that thanks to the use of more dangerous Bituminous Coal over Anthracite, combined with atmospheric conditions, and insufficient inspection and ventilation, were at least as likely as a mine. Bit coal has a dangerous tendency to self combust compared to Anthracite which could have produced the fire of sufficient heat to set off the magazine next door. In particular they noted a similar event in the USS New York shortly before the Maine's explosion where the same brand of coal that had sat for 2 weeks began to burn just 3 hours after being checked. The Maine went up 12 hours post inspection and the coal had been in that bunker for nearly 3 months! \n\nThe report that was prepared for Rickover: _URL_0_\n\nSo while modern scholarship has come around to an accident though it is not unanimous, and a few voices raised the suggestion at the time, the reporting of the papers holding Spain to account for the loss were not out of step with what the US government concluded themselves had happened, just with more gusto.\n\nI should recommend as another fine overview on the period and the coming together of many different interests as a good first reading on the topic: *The War Lovers: Roosevelt, Lodge, Hearst, and the Rush to Empire, 1898* by Evan Thomas. \n\n"
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2cuzx1 | why is the fetal position so comforting? | In other words, why do we curl up in the fetal position when we're in pain, are stressed, or are uncomfortable? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2cuzx1/eli5_why_is_the_fetal_position_so_comforting/ | {
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"Simple answer: *We don't know.*\n\nPostulation: The fetal position may be a learned response, similar to how some people sit and sway back and forth when distressed.\n\nSince we associate the position with fetus's, or young babies, it may be a visual cue to others, expressing \"I am not a threat\" or a request for attention and/or comfort.\n\nIt may also serve the functions of protecting the face, head, anterior vital organs, and the genitals from attack.\n\nFurthermore, try bending the other way... Not as comfortable, *right*?"
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qoa0m | How was sovereignty and colonialism different 2000 years ago? | I know places like Egypt had colonies, but it seems like with so much of a smaller world there's less opportunity to subjugate people and nations. Did nations still see some countries as 'lesser nations' that were in need of civilizing by their 'greater nations'? The only nation that really set itself apart from smaller countries was Persia, and that collapsed upon itself because of it. Sorry if this is vague | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/qoa0m/how_was_sovereignty_and_colonialism_different/ | {
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"You're talking about whether states had the same sense of external sovereignty as we do today, and the answer is generally no. The modern idea of noninterference in another state's affairs, at least in Europe, was only cemented in 1648 after the Peace of Westphalia that ended the Thirty Years' War. Before this, the Church as well as the Holy Roman Emperor had a lot of say in the administration of their demesne and fiefdoms. After this, the HRE and the church declined, allowing each nation to continue.\n\nSo back in, say, the Roman times, there were tons of colonies. It's way out of my area of expertise though, but I can assure you that Britain, modern day Eastern Europe, into Syria and North Africa were all colonized because the Romans didn't see those barbarians as on par with them. \n\nChina preferred the system of tributaries and suzerainty in its dealings with neighboring nations, so basically economic dominance leading to cultural dominance, especially in modern day Korea, Mongolia, into Central Asia on one side and Ryukyu on the other. The cultural dominance part definitely extended into Japan and Vietnam as well. For them, this was almost on par with colonialism, because China historically weren't really conquest-oriented. They did, however, have major campaigns against the Xiongnu (who may or may not be the ancestors of the Huns today), the Yuezhe, the Scythians, the Parthans, and a whole lot of folks, but I don't think they exactly treated them like states... more like nomadic peoples who are on their territories, that's all.\n\n ",
"The early Romans copied the Greek city-state method of when over populated, take excess population and ship them off to settle a colony. This was not the same as colonization as we think of it in British-Empire-in-America terms as this colony would be completely independent of their home city/country. They would acknowledge one was their parent state and have friendly relations/trade, but the parent state wouldn't feel obligated to protect, aid, nurture, etc their 'child'. \n\nThe later Romans used colonies as a method of helping to spread roman values, trade, and influence around, especially to control or repopulate boarder areas. These colonies were mostly filled with retired soldiers and other citizens. The colonies would be within the empire. Augustus settled approximately 150,000 retired soldiers in this way during his life, at his own expense. The colonies were approximately 2-3k in population, and some died out with the decline of the empire, but others survive to this day. These colonies were similar to other roman institutions in many ways - laid out in strict grid pattern (similar to military encampments), each had the same government structure which replicated Rome (annually elected officials, same positions and duties if not same titles as their equivalents in Rome). These towns would/could/might eventually have all of the structures you would find in other large cities, the forum, temples, theaters and/or amphitheaters, etc. They were located near water and in the valley floors (unlike in previous times where in say, Gaul, vast majority of settlements were hillforts for defensive purposes). \n\nI'm not sure if this was the \"turning point\" for colonies as I don't know anything about colonization during the middle ages, as if it existed in any form, I haven't heard of it. \n\nsource: History of Rome class I'm currently in ",
"I would like to simply point out that the notion of a \"nation-state\" did not exist back in the times that you might be referring to. In the words of one of my professors, \"God did not create the world and say, Let there be nation-states!\"\n",
"Hoo boy. This is a topic that I think is way more complicated than you know. Greek and Phoenician colonies, at least were fairly simple in purpose: They were large trading posts. Some of these, like Syracuse, morphed into large cities--after the Peloponnesian Wars and perhaps even before Syracuse was the largest and most powerful Greek city-state anywhere. Carthage, of course, became a very powerful empire in its own right. There doesn't seem to have been a \"cultural\" program, although the effect of Greek colonies on surrounding areas is a very interesting and very complicated topic that I could go into in depth if anyone wants me to.\n\nRoman colonies were much more complicated. To be sure, there were Roman colonies that were purely commercial--there are even a few in India. I don't mean to downplay them, because they are also quite complex and interesting--for example, there are a few Republican colonies found in France that were populated almost exclusively by slaves. The reasoning is that it is much easier for slaves to be intermediaries because they were not legally distinct from their owners, and so could conduct business deals on their owners' behalf. Sorry, didn't mean to get sidetracked.\n\nAnyway, as far as I can tell, you are wondering if Roman colonies had a civilizing mission. This is a very complicated topic that is still very much debated, but my answer is **no**. The Roman Empire did employ a rhetoric of \"civilizing the barbarians\" but there is very little evidence that this was anything more than just rhetoric. Provinces entered into the Roman way of life at their own pace, and heavy Imperial investment into the provinces is more or less undetectable until Hadrian, by which time all the provinces were more or less thoroughly Romanized. To be sure, the emperors did donate to building projects--think Baalbek--but that didn't really affect their character. Again, think Baalbek, which was very distinct from a Greco-Roman temple in form and function.\n\nSo what was the nature of the colonies? I, for one, would love to know that. Unfortunately, we don't really have good evidence for this. It is possible that colonies like Gloucester were populated by Romans who were transplanted from overcrowded cities. Or, conversely, it could have simply been an administrative designation with no real indication of its makeup (London was largely non-British, at least at the beginning, but was never a colony). Or it could be a mix of the two--founded by ex-legionaries and \"settlers\" but mostly populated by rural migrants. I favor the latter interpretation, but there is no way to know. A very interesting test case is Corinth, which was redounded as a military colony by Julius Caesar. However, it becomes a basically \"Greek\" city with a few generations.\n\nRepublican colonies are a different matter. Unfortunately, that is outside my specialty, although I will only caution against trusting Livy completely on this.\n\nI can't really give a clear answer, but that is because there is none."
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a3l6ra | why are the front and back cameras on smartphones not the same to begin with? why do they need to differ in quality? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/a3l6ra/eli5_why_are_the_front_and_back_cameras_on/ | {
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"cost and size.\nif all other variables remain constant, a bigger lens allows for better photos, as well as a bigger image sensor (the light sensing chip behind the lens). since they’re intended for different things, they just use different cameras. smaller cameras are also better at taking pictures of things closer to themselves (like a selfie)",
"Size. And cost.\n\nOne has to discreetly fit beside the screen, not look like a hideous lens obscuring your screen size, and only needs to take photos up close of your face. The other one needs to function as an actual camera and take detail, be able to zoom, etc.\n\n",
"Back cameras are much larger and are able to do many more things. There’s no need to have two of them on a phone. The front facing camera is mostly for selfies so there’s no need for a zoom or wide lens",
"Most people are never going to use the selfie camera for anything other than - you guessed it - selfies, or possibly video chat, which by their very nature never need to be all that high quality. Putting a top quality camera in the front camera position would just increase the cost for a benefit, from most people's perspective, of very little. ",
"The bette the camera the more it costs to make. So the phone markers chooses cameras that are just good enough for what they are used for.\n\nThe back page camera is often used for big scenes with many details and need more data. The front camera is often used for selfies or similar, where details are not as needed or necessarily good thing (which is why we have filters that smooth the skin etc).\n\nHistorically the front camera was for video chat, which was limited by bandwidth and data, makings low resolution good enough. \n\nEdit: Switched back/front. D'uh!",
"Every penny saved on a component, when you're shipping several million units, adds up quick!!!\n\nIf the selfie camera just needs to be adequate enough to do a good enough job, it's hard to justify the few extra pennies on the component, especially since selfie cams are not that popular of a selling point. "
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3dqn0a | Why are gamma rays so hard to stop? | Doing some research on why glass is transparent, I understood that visible light doesn't have enough energy to excite the electrons in the SiO2 molecules, so it simply passes trough the glass, making it transparent. UV light does have enough energy, thus getting absorbed by glass.
But gamma rays are extremely high energy photons, they should have enough energy to excite any electron, so why doesn't every material absorb them?
Sub question: is every material transparent to a certain wavelength of light transparent to every lower energy wavelength of light? | askscience | http://www.reddit.com/r/askscience/comments/3dqn0a/why_are_gamma_rays_so_hard_to_stop/ | {
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" > But gamma rays are extremely high energy photons, they should have enough energy to excite any electron, so why doesn't every material absorb them?\n\nGamma rays typically have *more than enough* energy to excite atomic electrons. They have enough energy to ionize atoms (kick electrons out of their bound states) or even excite/break apart atomic nuclei.\n\nThe energy loss of high energy photons through matter is dominated by three processes: the photoelectric effect (kicking electrons out of their bound states), Compton scattering (scattering of photons off of electrons or nuclei), and pair production (a gamma ray moving through matter with enough energy can produce and electron/positron pair).\n\nBut to answer your question, gamma rays are hard to stop because they have a lot of energy to give up, whereas visible or UV light has less energy,",
"The answer given by /u/RobusEtCeleritas is not a good answer, although it naively sounds like it makes sense. The reason why glass is transparent to gamma rays is not primarily because it takes a lot of interactions to absorb its energy, but because gamma rays tend to not interact frequently with the material.\n\nFor example, any photon (gamma ray or not) that frees electrons via the photoelectric effect will be completely absorbed, with all of the photon's energy being transferred to the electron (any energy above the binding energy will simply result in an electron with greater kinetic energy). If this occurred just as frequently for gamma rays in glass as it does for UV rays, then gamma rays would be absorbed just as well.\n\nThe best explanation that I can think of that doesn't rely heavily on advanced physics and math is related to the effective 'size' of a gamma ray. The wavelength of light is very loosely analogous to its size (or its interaction cross-section). The wavelength of UV light is between roughly 1 to 100 nm, which is very large by atomic standards (atoms are about 0.1 to 0.5 nm in diameter). The spacing of atoms in glass and in most materials is also much smaller than the wavelength of a typical UV ray, and so the UV photon is very likely to interact with it.\n\nThe longest wavelength gamma rays are about 1000 times smaller than the shortest wavelength of UV rays, and much smaller than atoms and the atomic separation in a material. They are much more likely to pass through it then without really noticing the matter they're traveling through.\n\nA crude analogy is throwing basketballs and ping pong balls through the poles of a fence, where the poles represent the atoms of a material and the balls are UV and gamma rays, respectively. The larger basketballs are much more likely to hit the poles, whereas most of the ping pong balls will go between them completely undisturbed.\n"
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5p4xi5 | If you flip a coin an infinite amount of times, will you also at some point have an infinite streak of heads? | askscience | https://www.reddit.com/r/askscience/comments/5p4xi5/if_you_flip_a_coin_an_infinite_amount_of_times/ | {
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"For any fixed n, you will (almost surely, aka with probability 1) have a string of n heads in a row sometime; if you divide up your throws in sets of n, you have probability 2^(-n) of getting all of them heads in that set - so prob. of never getting n successive heads in k*n throws is at most (1-2^(-n))^k, and as the amount of throws (and k) increases, this approaches 0.\n\nHowever, \"at some point have an infinite streak of heads\" means that after N throws, all the remaining coin tosses result in heads; but that happens with probability 0.",
"Consider the sequence a_n with a_k = 0 or 1 means the kth flip is tails or heads, respectively.\n\nThe series sum{n=1,...} a_n 2^(-n) is between 0 and sum{n}2^(-n) = 2, so it converges to a real number A. If the sequence a_n eventually becomes \"heads-only\" (i.e. there is a finite N such that n > N - > a_n=1), then A must be rational.\n\nBut the set of rational A is countable, while the set of [real] A is not countable. So the probability of a randomly chosen A being rational is 0, and the probability of getting an infinite streak of heads is 0; but since there actually are rational A, it is described as \"almost never\" happening.",
"In a sense, but not really. There is a subtle distinction in where you apply the infinity. \n\nThere is no limit to the length of the longest streak. I can choose any number from a choice of infinity, and there is a streak that has that length. In this sense a streak can be infinitely long.\n\nHowever, there is no streak that continues infinitely. No matter how long the streak is, by continuing to flip infinitely many times, it will eventually hit a tails to end it. In this sense all streaks are finite and not infinite.",
"Ain't this the same as asking if there are more pair numbers than natural numbers? In which case both sets are infinite in the same \"size\" of infinite? I don't remember that much from my logics classes and set theory but I would like to know if the case is the same"
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9m8d63 | how does an epipen work to help severe allergies and why don’t we use it for moderate/mild allergies? | I’ve always wondered why people use an epipen when having a severe allergic reaction to things like peanuts or shellfish but we don’t use it for people who get bad allergies to things like pets or pollen? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9m8d63/eli5_how_does_an_epipen_work_to_help_severe/ | {
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"Because it’s a huge strain on the system of the person receiving it. It’d be like killing an ant mound with a bazooka — it would work, perhaps, but it’s not a thing you’d do often, and there are better, less-scorched-earth tools that are better suited to the situation. ",
"It causes bronchial dilation so your airway stays open when it’s trying to close in anaphylaxis. It increases blood pressure too. It’s the same thing as adrenaline. It’s only meant to be used in ER situations. It does nothing for histamine which is the cause of most every day allergies. ",
"An epipen contains epinephrine, commonly known as adrenaline, one of the main hormones released by the body when PANICKING OMG THERE'S A LION. \n\nIt's great for doing things like restarting your heart, lifting a car off your child, or removing blood flow from parts of your nose and throat that might be blocked by an allergic reaction, thus allowing you to breathe, but it also removes blood flow from your digestive system until your body can filter it out which... Well, apart from the explosive diahrroea brought on by extended use, your stomach will eventually dissolve it's own lining and dump a strong acid into your bloodstream, if that lining isn't grown back. \n\nLack of blood flow inhibits your body's ability to grow back your stomach. Which in mediocre cases result in ulcers. \n\nEpinephrine is healthy if released by your body occasionally. Injecting it on a regular basis isn't. "
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2sqcf7 | if oil has a finite supply and is steadily running out, why does the price per barrel fluctuate? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2sqcf7/eli5_if_oil_has_a_finite_supply_and_is_steadily/ | {
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"It comes down to basic economics of supply and demand.\n\nThe amount of oil in the ground is finite but the amount of oil that has been pumped to the surface and available for use changes on a regular basis. Currently the US, Iraq and Libya are pumping more oil than in the past. Combine that with the fact that Saudi Arabia has decided not to slow its own production and you have a large supply.\n\nOn the other side of the equation you have demand. China and Europe are currently using less oil than they were a few years ago.\n\nWhen you have high supply and low demand the price tends to drop.",
"Actually oil reserves grows as time goes on : ) Its because new oil is being found everyday.\nIn 1944 there \"were\" 51 billion of oil barrels..\nBetween 1945 and 2003 917 billions were used. In 2003 there were known 1,266 billion of oil reserves.\n\nIf you were to take all known oil reserves in 1980 and rate at which oil were used this year you would conclude that we gonna run out of oil in 25 years. Do you recall something like that happening? : )\n\n\nThere is cool lecture on that _URL_0_",
"There IS a finite supply, but its a VERY large finite supply, so it wont run out for a very very long time. The price is rising, but very very slowly over the long term. \nThe more common price fluctuations are due to other more immediate factors, as stated in other comments."
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1t4ye1 | what causes cars to sometimes explode when they flip over in a crash? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1t4ye1/eli5what_causes_cars_to_sometimes_explode_when/ | {
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"Cars generally don't actually tend to blow up.\n\nThe only reason a car would explode would be a spark or fire reaching the gas tank and even then its not quite like how you see it in movies. ",
"As a 25+ years firefighter / Paramedic I have NEVER seen a car that has exploded in an accident. And have rarely even seen cars catch fire. The few that I have seen catch fire are usually because the fuel line or gas tank has ruptured, and the fuel comes in contact with hot metal (Catalytic converter or engine block) Yes these fires can consume a car (and occupants) quickly but not like in the movies."
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8sb7r3 | What is the history of Rome's Colloseum from post-roman times through to modern time? | The Colloseum is still standing today. It was in use at one point as an arena, and then it wasn't at some point. When was its last use as a a typical Roman arena? And what did medieval Italians think of it? Or during the renaissance for example? Was there some kind of active preservation through the years? Are their paintings of it that show it's erosion? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/8sb7r3/what_is_the_history_of_romes_colloseum_from/ | {
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"The emperor Honorius abolished man vs man gladitorial games in AD 404. There were some animal games (venationes) in 503, and in 508 the place suffered earthquake damage. Rome's population had plummeted by about two thirds over the previous century and although there were idle rich about, these spectacles were not cheap to put on. The last recorded was in celebration of the consulship of Anicius Maximus in 523. The Ostrogothic ruler of Italy Theodoric the Great (illegitimate some of Alaric the Goth) gave his permission, but also made it clear that [he didn't think much of the games](_URL_3_) as an occupation for respectable men. If there were others after that, we have no record.\n\nWhich left the structure, an impressive pile of second hand building material. First to go were the bronze clamps used to secure blocks, much as abandoned buildings today get stripped of copper piping. the probable culprit is Totila, who[ sacked the city in 545](_URL_1_). (Obviously the building didn't fall because of the metal being taken out, but the architects who built the thing had a large budget, so why not err on the side of safety?) Rome's population plummeted, those who remained preferred to gather by the river (no more aqueducts, and toting water is tiresome). The Colosseum went into decline, unnerving to the locals who thought it a bit creepy.\n\nBy the ninth century things in Rome were looking up again. We have evidence of people turning some of the interior space into living quarters and animal stables, and the center into a market. It must have made a nice little neighborhood, if you didn't mind the trek to the river to get water, or if you could afford the water carriers who would do it for you for a price.\n\nAlas, 1084, Robert Guiscard comes to sack the city (see [here](_URL_0_) for more), leaving in his wake a city broken down into zones controlled by various powerful families and their bully boys (think gang turf rivalry). The Colosseum fell under control of the Frangipane family. With one brief interruption (rebelling citizens, tired of the baronial families, threw the lot of them out for the period of 1144-1159 and tried to restore an ancient Republic) that family held it until the Anabali family wrested the building from them at the end of the 12th century. They in turn had to give it over to the church in 1312.\n\nAnother serious earthquake in 1349 more or less put it out of commission for shelter. Instead it became a quarry for building material, a great source of profit for the Benedictines who held the lease hold of the place. The area continued in that role for the next hundred years; much of St Peters started life at the Colosseum.\n\nYou can see [woodcuts ](_URL_2_)of the building dating from the fifteenth and sixteen century. Much of what you see today is restoration. Serious restoration.\n\n(I used to live about a mile from it, and have always taken an interest in the place.)"
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eyq1ij | why we get sleepy in situations that sleeping can kill us | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/eyq1ij/eli5_why_we_get_sleepy_in_situations_that/ | {
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"What situations do you mean?",
"Yeah I've always wonder why we get sleepy after hitting your head. I remember my parents always telling me to not fall asleep while they drove me to the hospital....",
"The bit of your brain that decides when to be sleepy can't access higher rational thought, it's based on the brain's physiological status. \n\nYour brain gets sleepy when the chemistry in your brain indicates that it needs to sleep, along with some hormonal inputs from the body like adrenaline which tell it that something critical is going on and you need to be awake. But the part of your brain thinking \"I better not fall asleep while driving because I could crash\" can't communicate that information to the part of the brain that decides when to be sleepy. As far as that part of your brain is concerned, if you are driving late at night you are sitting calmly in a quiet, dark place and you haven't slept in a while and now would be a good time. \n\nThis is not entirely terrible, it makes it harder for you to sleep-depriving yourself to a dangerous extent. And it's not like your conscious mind can't override sleepiness for a long time. But the modern world has a lot of situations where it would be a bad idea to be sleepy but there are no obvious cues the sleepiness part of your brain is adapted to interpret, and this causes problems (like, you aren't going to be sleepy if there's a large predator staring at you, because you are innately going to be adapted to respond to that. But there's no innate adaptation to staying awake while driving)."
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6adtg6 | Why was Henry 1 Charter of liberties largely ignored by monarchs until the issuing of Magna carter? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/6adtg6/why_was_henry_1_charter_of_liberties_largely/ | {
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"To answer the question in depth we first have to look at the circumstances of the charter. After William II. Rufus died on August 2nd of 1100, Henry hurried first to Winchester - to secure the royal treasure - and then to Westminster, where he was crowned king on August 5th, despite only a handful of nobles being present and both archbishops of the kingdom unavailable. This haste was necessary though because Henry's oldest brother, Robert Curthose, also had a very good claim to the throne of England, even though during this time he was still on his way back from the first crusade.\n\nSo, either on the day of his coronation or a few days after (there is no consensus on this, but for this question it can be ignored) Henry issued the charter, which was largely based on the threefold coronation oath common at the time, and had it distributed in the kingdom. It's not entirely sure if the initative to the charter came from Henry himself or if Henry was pressed by the nobles, as many of the points in the charter discussed the relation between king and nobles, especially the status of heirs and widows. In any case the charter can be seen as a token to secure Henry's reign which wasn't very stable in its first years. The charter was confirmed again by Henry when his brother Robert set sail in 1101 to gain the english throne which he laid claim on. In the end Robert could be paid off by Henry and the first rough part of his reign laid behind him.\n\nSo, why is this important? The monarchs following Henry simply had more support in the nobility than Henry had in his first years. Stephen, at least in the beginning of his reign in England, had the support of the nobles while Mathilda and Geoffrey of Anjou were busy in Normandy until 1144. In 1154 Henry II could wait six whole weeks between the death of Stephen and his own coronation because he didn't have to fear anyone taking the throne in the meantime. And Richard even had the support of the french king Philipp August, even though that friendship broke apart quite soon.\n\nDespite this I wouldn't say that the charter was forgotten. Stephen and Henry issued coronation charters themselves, and the charter of liberties was nothing else before it became the charter of liberties (the name was applied later on). Both of them even referenced the coronation charter of Henry I, even though their charters weren't as long as Henrys. Henry II basically wrote *I give you all the good laws that my grandfather Henry gave*. So while the contents may have been ignored or simply not enforced, a tradition of distributing the oral coronation oath in written form seems to have taken hold in England. Henry II was later on even confronted by Thomas Becket who explicitly referred to Henry II's coronation charter.\n\nThe charter then got new gravitas when Stephen Langton used it as a blueprint for Magna Carta. This may have been caused by a rising interest in justice and law. J. C. Holt, Magna Carta, 3rd ed., Cambridge 2015, p. 25, writes on this:\n > [...] there were many copies of Henry I's Charter in circulation in the early years of the thirteenth century, and [...] they were studied intensively – which is what has always been apparent from the chroniclers, inaccurate though some of the details of their accounts have been judged to be.\n\nThis may be the cause why the charter comes up again more than a century later. In the events preceeding Magna Carta the charter of liberties came in handy for the barons and especially Stephen Langton.\n\nI hope this answers your question at least partly. Feel free to ask further. I have to admit though that my strong side at the moment is the time of Henry I and not really the time of Magna Carta.\n\nHere is some further reading.\n\nOn the Charter of Liberties:\n\nTeunis, Henry B., The coronation charter of 1100: a postponement of decision. What did not happen in Henry I's reign, in: Journal of Medieval History 4/1 (1978), pp. 135–144.\n\nDalton, Paul, The Accession of King Henry I. August 1100, in: Viator 43/2 (2012), pp. 79–109.\n\nOn Henry I in general still:\n\nHollister, Charles Warren, Henry I (Yale English Monarchs), New Haven 2001.\n\nOn Magna Carta:\n\nHolt, J. C., Magna Carta, 3rd ed., Cambridge 2015.\n\nCarpenter, David, Magna Carta, London 2015.\n\nedit: English is not my mother tongue, so please be kind."
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2fceq9 | For those who know a bit about the Arthurian legends.. | I have a few questions for you!
I've always loved the Arthurian tales (actually ended up studying them briefly when I was still at uni, though that was a while ago now and I'm not knowledgable enough to be certain on a few points, and I want to be accurate!)... but anyway, long story short I am looking at getting a tattoo based around the tales (focusing on Excalibur for reasons I won't get into, possibly incorporating the round table into the hilt somehow?? But like I said, I want it to be quite accurate, so I thought I'd just come check my info with people who know more than I do before I start designing it!
I have just a few questions!
What kind of sword is Excalibur? I had a quick flick through my copy of Malory's 'Le Morte D'Arthur' but couldn't spot anything concrete.. I'm thinking probably a spatha or a claymore?
Also, does someone know how many seats were at the round table (and, IIRC, wasn't each one to represent a virtue - like 'courage', 'honour', etc? Or have I made that up?)..
And, last question, can someone confirm that (in most versions, anyway) the writing on Excalibur is 'take me up' and 'cast me away'?
Thanks in advance for your help guys, I appreciate it! | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2fceq9/for_those_who_know_a_bit_about_the_arthurian/ | {
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"The Arthurian stories have been retold and recycled for centuries (if not over a thousand years - it depends on how we date the Welsh Arthurian stories). Thus they have amalgamated into a mish-mash of features. Any tatoo or image of Excalibur will not be historical but only representative of one particular tradition or one particular story (*Le Morte Darthur* is by no means archetypal in its treatment of the Arthurian story).\n\nUltimately you might want to ask yourself what kind of Arthur you want depicted. The Post-Roman Arthur, the knightly Arthur, a modern Arthur. They're all equally valid and equally flawed. Accuracy is an illusion in this kind of endeavour.\n\n1) Excalibur\n\nI had a look at Kenneth Hodges's *Forging Chivalric Communities* because I remembered he noted something odd about Excalibur. Apparently there are two of them in *Le Morte*. The first is taken from the stone, the second is bartered away from the Lady of the Lake:\n\n > The first Excalibur, the sword in the stone, appears after a consultation of Merlin and the Archbishop of Canterbury, but it appears outside of the church instead of on the high altar and Arthur draws it one his own, alone, without receiving it from the bishops. After it breaks, he receives a new one, not by purchasing it from the church, but by bartering for it with the Lady of the Lake. Finally, after Morgan steals the sword, he reclaims it in combat with the assistance of Nyneve.The multiple providers of the sword reflect the multiple sources of authority: personal prowess, supernatural worthiness,women’s good will.\n\n > Hodges, K., *Forging Chivalric Communities in Malory's* Le Morte Darthur, (Basingstoke, 2005), p.36. \n\nOf the second Excalibur, the scabbard is more important than the sword in Malory's *Le Morte Darthur*: \n\n > Sir, said Merlin, look ye keep well the scabbard of Excalibur, for ye shall lose no blood while ye have the scabbard upon you, though ye have as many wounds upon you as ye may have. So after, for great trust, Arthur betook the scabbard to Morgan le Fay his sister, and she loved another knight better than her husband King Uriens or King Arthur, and she would have had Arthur her brother slain, and therefore she let make another scabbard like it by enchantment, and gave the scabbard Excalibur to her love; and the knight's name was called Accolon, that after had near slain King Arthur.\n\n > [Source](_URL_1_), Ch. XI.\n\n2) Seats: Virtues\n\nNo, they are not. You may be mixing this up with the 'Perilous Seat' which would only be sat by the most virtuous and worshipful of Arthur's knights. This was, of course, Galahad. \n\nI haven't investigated (and honestly have no desire to!) how many knights constituted the Round Table, so I offer [this](_URL_0_) with the warning that it might be wrong. At any rate, there are a few too many to fit on a hilt.\n\n3) Inscription\n\nLike I've said, it doesn't really matter. Find one, pick one, and be happy with it. Neither of those phrases appear in Malory's *Le Morte Darthur* verbatim but if you scrawl through the source I've provided you might be able to find one."
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8ta7gw | What is the biochemical origin of caffeine dependence? | There's a joke that if you've been drinking coffee for a long time, when you wake up you'll need a coffee to get you back to the point where you were before you started regularly drinking coffee. But, if you stop for a week or two, your baseline goes back up. What happens to regular coffee drinkers to lower their baseline wakefullness, and is it chiefly neurological or psychological? | askscience | https://www.reddit.com/r/askscience/comments/8ta7gw/what_is_the_biochemical_origin_of_caffeine/ | {
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"Caffeine is a nonselective adenosine receptor antagonist, acting at A1, A2a, A2b, and A3 receptors (it also binds to a few other receptors, but we’ll ignore those for simplicity’s sake). From knockout studies in mice, it appears A2a is critical for the stimulating effect of caffeine. In the brain, Adenosine levels fluctuate as the day passes with the highest levels at night. Higher levels of adenosine produce a drowsiness effect. When you consistently apply an antagonist to a cell, a common response is the cell will upregulate the particular receptor that is being antagonized. As such, consistent caffeine intake can result in an upregulation of adenosine receptors [1]. When you do not intake caffeine, you thus experience a heightened response, or a sensitization, to adenosine, and thus feel an increase in drowsiness. \n \n1. Cell Mol Neurobiol. 1993 Jun; 13(3): 247–261.",
"[NCBI publication ](_URL_0_) \n\nCaffeine acts as an antagonist at adenosine receptors, thereby blocking endogenous adenosine.25,26 Functionally, caffeine produces a range of effects opposite those of adenosine, including the behavioral stimulant effects associated with the drug.27 Importantly, caffeine has been shown to stimulate dopaminergic activity by removing the negative modulatory effects of adenosine at dopamine receptors.28 Studies suggest that dopamine release in the nucleus accumbens shell may be a specific neuropharmacological mechanism underlying the addictive potential of caffeine.29–32 Notably, dopamine release in this brain region is also caused by other drugs of dependence, including amphetamines and cocaine.33,34 In addition to the direct effects of caffeine on adenosine receptors, a recent study has shown that paraxanthine, the primary metabolite of caffeine in humans, produces increased locomotor activity, as well as increases in extracellular levels of dopamine through a phosphodiesterase inhibitory mechanism.35\n\nUp-regulation of the adenosine system after chronic caffeine administration appears to be a neurochemical mechanism underlying caffeine withdrawal syndrome.36 This mechanism results in increased functional sensitivity to adenosine during caffeine abstinence, and it likely plays an important role in the behavioral and physiological effects produced by caffeine withdrawal.\n\n[_URL_0_](_URL_0_) ",
"Fun fact: it's the same mechanism that leads to tolerance and dependence on other addictive psychoactive drugs like nicotine, cocaine, heroine, etc. \n\nYour brain synapses adapt to the presence of the drug, so the brain's baseline ”normal” state requires the drug to be present. And when the drug is removed you get essentially the opposite of the drug's effects.",
"Caffeine is an adenosine antagonist. Adenosine makes you feel tired and antagonists block receptors. It doesn't actually give you energy by stimulating excitatory receptors like an amphetamine. However, both changes cause the brain to counter-regulate the effects of the substance and result in long-lasting physiological accommodations. This causes withdrawals when you take the chemical away and they can potentially last YEARS depending on your personal genes and lifestyle. ",
"There are several components in your question, which, require a minimal scientific understanding in order to understand the answer. Your title question asks about & ldquo;*the biochemical origin of caffeine dependence* & rdquo;, but your clarifying text actually focuses on just one component, namely, increased tolerance to a given dose of caffeine.\n\nFor the sake of simplicity, let's consider two related, but somewhat orthogonal concepts and an oversimplification of what they really mean.\n\n1. Pharmacology: What does a drug do to the body?\n\n1. Pharmacokinetics: What does the body do to a drug?\n\nPharmacologists and pharmacokineticists often work together, but they are focused on different problems. While pharmacologists want to understand how a drug imparts a particular effect on the body, pharmacokineticists want to understand the answers to two primary questions:\n\n1. What quantity of a drug needs to be administered to achieve a certain pharmacological effect?\n\n1. How often does that quantity need to be administered?\n\nOther people ITT have focused on the pharmacological aspect of caffeine (*i.e.* **WHY** does it make you feel the way it does?), but they haven't focused on the tolerance aspect, wherein you need successively larger doses to achieve a certain effect. For this question, we turn to pharmacokinetics.\n\nCaffeine is eliminated from the body via several mechanisms. However, for most people, approximately 70% of caffeine is eliminated from the body via metabolism by one particular family of enzymes in the liver called CYP1A2. ^1 Within the liver, there are different families of enzymes responsible for metabolism. These families have different specificities/affinities for different compounds in our body (AKA *substrates*). As the affinity between a substrate and an enzyme increases, the ability of the enzyme to transform that substrate increases.\n\nAs mentioned above, in the case of caffeine, CYP1A2 is the primary enzyme responsible for transforming caffeine as part of the process for eliminating it from the body. The interesting thing about many (but not all) liver enzymes is that they can be *inducible*, meaning that there are feedback loops in your body's biochemistry that instruct the body to *upregulate* (increase) or *downregulate* (decrease) the levels of these enzymes in response to a stimulus.\n\nIn the case of caffeine, CYP1A2 happens to be inducible.^2 As you consume more caffeine, various regulatory mechanisms sense this increased load and tell the body to increase the amount of CYP1A2 metabolising enzymes. Therefore, when you consume 10 mg of caffeine daily (*ie* the dose) for several weeks, the amount available in your bloodstream (*ie* the exposure ) is decreased for a given dose because your body is clearing the caffeine more quickly than it did originally (*ie* your baseline). If you stop consuming caffeine (and any other compounds that could induce CYP1A2), your body will sense the decrease and levels of CYP1A2 will be decreased.\n\n1. Thorn CF, Aklillu E, McDonagh EM, Klein TE, Altman RB. PharmGKB summary: caffeine pathway. Pharmacogenet Genomics [Internet]. 2012 May [cited 2018 Jun 23];22(5):389–95. Available from: _URL_1_\n\n1. David A. Flockhart, Zeruesenay Desta. Chapter 21: Pharmacogenetics of Drug Metabolism. In: Robertson D, Williams GH, editors. Clinical and Translational Science: Principles of Human Research [Internet]. 1st Ed. Amsterdam: Acad. Press; 2009. p. 301–17. Available from: _URL_0_\n\n\n---\n\n**TL;DR:** OP's question requires a minimal understanding of *pharmacology* and *pharmacokinetics* in order to understand the answer to the question.\n\n---",
"Most dependencies on substances start by a phenomenon known as receptor up/downregulations; which is when a substance that is known to bind to a specific receptor to cause it's intended effect is abused to the point that the body has to make more receptors. In caffeine, the receptor in question is adenosine, and caffeine will bind to it in a manner that will render it inactive. Adenosine receptors that are active will send out the signal that the body is starting to feel tired, so blocking said receptor will bypass that signal, and you will be more alert. The body doesn't like you bypassing this, though, so it makes more receptors to return to baseline function, aka upregulation. This is normal and expected in tolerance. Dependence occurs when the dosage of caffeine continues to increase and the receptor upregulation is pushed so far up that the person in question cannot function without caffeine.\n\nThere are also other drugs that work through the same sort of pathway. Opioid are one which works along opioid receptors, albeit the difference is opioid activate said receptor rather than block it, and food is actually another; obese people are likely to have lower sensitivity to insulin (downregulation) compared to people at a more appropriate bmi.\n\nEdit: some auto-correct ",
"This question conflates coffee with caffeine.\n\nCoffee is not just caffeine; it also contains substances that greatly increase the potency and addictiveness of various other psychoactive substances, including caffeine.\n\nThese so-called ß-carboline alkaloids are inhibitors for human monoamine oxidase enzymes, MAOs.\n\nThere are two types of MAOs, MAO-A and MAO-B. Both are very important in breaking down brain neurotransmitters, and inhibiting their activity causes brain neurotransmitter levels to rise.\n\nSince these compounds inhibit both types of MAO, MAO-A and MAO-B, they increase the levels of the neurotransmitters serotonin, dopamine, noradrenaline and adrenaline. They do so by binding to the MAO enzymes, making them unable to bind to the neurotransmitters to break them down like they normally do.\n\nThis means that any other drugs that work by releasing these neurotransmitters, or inhibiting their reuptake into neurons, are going to have a more substantial neurological effect. This essentially means that almost every mind-altering substance known to man will have its reinforcing effects potentiated by coffee – and tobacco smoke, malt beverages, barbecued foods, basically everything that contains protein and is heated for long periods. Soy sauce is *loaded*.\n\nThese chemicals are called heterocyclic aromatic amines (HAAs for short), a subgroup of which beta-carbolines are. The typical beta-carboline is called norharman; some others are called harman, harmalol, harmaline, harmine, tetrahydroharmine, et cetera. As a group, they also called Harmala alkaloids.\n\nYou may recognize the name; it comes from the plant *Penganum harmala*, an ingredient of the psychedelic brew Ayahuasca used traditionally as a sort of psychiatric medicine by South American shamans.\n\nWhat's so interesting about these so-called Harmala alkaloids is that they all tend to inhibit the activity of MAOs. Some of them are biologically active at nanogram dosages per kilogram body weight. Coffee and tobacco smoke are the two most significant sources of these alkaloids in the human diet. \n\nSince they directly increase the effects and addictiveness of all kinds of drugs – even common, \"mild\" ones like nicotine and caffeine – they are very reinforcing in themselves when administered regularly.\n\nSome people have an increased susceptibility to tobacco and coffee addiction due to genetic differences in MAO activity; there are several genetic variants of both MAO-A and MAO-B, which cause all of us to have very different rates of metabolism for the key neurotransmitters detailed above.\n\n-----\n\nHuman monoamine oxidase enzyme inhibition by coffee and ß-carbolines norharman and harman isolated from coffee \n_URL_4_\n\nNorharman and harman in instant coffee and coffee substitutes \n_URL_11_\n\nIdentification and occurrence of the bioactive ß-carbolines norharman and harman in coffee brews \n_URL_2_\n\nContribution of Monoamine Oxidase Inhibition to Tobacco Dependence: A Review of the Evidence \n_URL_12_\n\nHuman monoamine oxidase is inhibited by tobacco smoke: beta-carboline alkaloids act as potent and reversible inhibitors. \n_URL_7_\n\nMonoamine Oxidase Inhibition Dramatically Increases the Motivation to Self-Administer Nicotine in Rats \n_URL_6_ \n\nTransient behavioral sensitization to nicotine becomes long-lasting with monoamine oxidases inhibitors. \n_URL_0_\n\nSmoking Induces Long-Lasting Effects through a Monoamine-Oxidase Epigenetic Regulation \n_URL_8_\n\nMonoamine oxidase A knockout mice exhibit impaired nicotine preference but normal responses to novel stimuli \n_URL_5_\n\nHarman in Alcoholic Beverages: Pharmacological and Toxicological Implications \n_URL_13_ \n \nHarman and norharman in alcoholism: correlations with psychopathology and long-term changes. \n_URL_10_\n\nThe role of beta-carbolines (harman/norharman) in heroin addicts \n_URL_9_\n\nRegarding MAOA and MAOB genetic variability:\n_URL_1_\n_URL_3_\n"
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"http://omim.org/entry/309860",
"http://www.sciencedirect.com/science/article/pii/S0024320505007514",
"https://academic.oup.com/hmg/article/15/18/2721/641681",
"http://www.jneurosci.org/content/25/38/8593.abstract",
"http://www.ncbi.nlm.nih.gov/pubmed/15582589",
"http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0007959",
"http://www.sciencedirect.com/science/article/pii/0767399X96800769",
"http://www.ncbi.nlm.nih.gov/pubmed/8651457",
"http://www.sciencedirect.com/science/article/pii/S0308814609013806",
"http://ntr.oxfordjournals.org/content/18/5/509.short",
"http://www.ncbi.nlm.nih.gov/pubmed/3067615"
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1vfx6i | Is there more oxygen in water or air? | Is assume there is more O2 in air but if you took the oxygen from H2O, does it add up to more oxygen than total oxygen in all the molecules in air?
Also, would be possible to make a device to harness the oxygen in H2O to breathe it? ( I'm imagining some fancy little device you put in your mouth and then you can breathe water. ) | askscience | http://www.reddit.com/r/askscience/comments/1vfx6i/is_there_more_oxygen_in_water_or_air/ | {
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"I am not sure of the question, but if you mean whether an equivalent volume of air or water holds more oxygen, the answer is (under typical conditions assuming the dissolved oxygen is at equilibrium with the air) the air. Oxygen only dissolves to the extent of a few milligrams per liter of water (around 8mg/L at 20C). On the other hand, the density of air is around 1200mg per liter. Since the air is about 23% oxygen by mass, this means there is approximately 276mg of oxygen per liter of air. ",
"Do you mean like...if you somehow split the H2O and got all the oxygen out of it, would there be more from that than there is in the air?\n\nYes. Much more. Pure water has a molarity of roughly 55, so if you somehow split that all up you would end up with roughly 55 moles of O per liter. Oxygen is about 16 g/mole, so this gives you 55 * 16 == 880 grams of Oxygen per liter of water.\n\nu/High-Curious already provided us with the amount of oxygen in air, about 276 mg oxygen per liter of air. 880 g/liter is much more than 276 mg/liter, so yes, there is a greater total weight of oxygen atoms in water than in air."
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d68i1f | A couple universe related questions from a layman - can you explain any of these things? | I might have done some thought gymnastics to come to weird ideas regarding this, so please bear with me.
If energy is finite, wouldn't the universe be finite?
If energy is infinite, wouldn't the universe be infinite?
If energy is finite, wouldn't matter be diluting as an infinite universe expands?
If the universe expands, there's more space with every single second passing. More space would require more matter, since an absolute negative pressure/vacuum isn't possible (iirc). Respectively, since "regular" matter doesn't really seem to be filling these massive voids, something else would be filling it, which (from my understanding) would be dark matter. So how does dark matter not dilute as the universe expands? If the universe was somehow generating more dark matter as it expands, wouldn't there also be a possibility that it would keep generating just as much "regular" matter?
If the universe came from nothing, and all energy can be neither created or destroyed, just changed, then the universe would contain a total energy of zero. If light, "regular" matter, etc. are considered positive energy, what is actual negative energy?
And what use is there for the universe in particles and anti-particles constantly nullifying each other everywhere, all the time? | askscience | https://www.reddit.com/r/askscience/comments/d68i1f/a_couple_universe_related_questions_from_a_layman/ | {
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"Couple corrections that weren't made.\n\nThe universe does not create new dark matter as it expands. It appears you are confusing dark matter and dark energy, two largely unrelated concepts. Overall dark energy increases because the energy density of empty space is constant. New space has as much energy density as old space and does not \"dilute\" with expansion.\n\nThe universe's energy appears to be net zero from observations of town curvature"
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drto7p | how can a single pixel on a tv screen change to so many different colors? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/drto7p/eli5_how_can_a_single_pixel_on_a_tv_screen_change/ | {
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"You remember mixing paint colours when you were a kid? A single pixel is made up of a tiny blue light, a tiny red light, and a tiny green light. It can be any colour just by controlling how strong each of these colours shines inside it. More modern screens (e.g., Liquid Crystal Display) have fancier technology but let’s stick to ELI5.",
"Your eye have 3 types of cone cell that detect light color. One type is most sensitive to blue light, one to green light and one to red light . So any color you can see is a combination of signal from the three types of cones.\n\nA monitor have red green and blue sub pixel where each primary stimulate only on cone type. By changing the amount light each sub pixel emit can use get any response from the eye and see any possible color. So by exploiting how the human eye work you can produce any color with light on only 3 colors.\n\n It is a bit simplified explanation and a RGB monitor can't show all colors you can see with you naked eye. I suggest looking at [Technology Connections - The Weird World in RGB](_URL_0_) for entertaining explanation of color vision and RGB work and the limitations."
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4mh538 | if insects and arachnids don't have feelings, than what would trigger them to act if in danger? | If the title doesn't make much sense, this is what I mean. For example, I saw a gif of a toilet being flushed and a spider going down with it. The spider is rapidly wriggling its legs as if it's trying to save itself. If they really can't sense fear, or feel threatened, then why would they bother try to stay alive? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4mh538/eli5_if_insects_and_arachnids_dont_have_feelings/ | {
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"Because reflexes and involuntary reactions often have little to do with emotion. Just like when a doctor hits you in the knee with the rubber mallet or when you stub your toe in the dark. Your reaction is to make a jerking motion but it doesn't necessarily trigger any significant emotions. Except maybe you'll get pissed off after stubbing your toe.\n\nAlso, studies suggest insects do in fact feel emotions such as fear and pain.\n\n_URL_0_",
"Insects and arachnids do have at least some feelings such as fear and pain. What they don't have is the self awareness and intelligence needed to contemplate what those feelings mean."
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139ef8 | the us and why israel is important to the us. | It seems like both republicans and democrats think Israel is important. Can somebody cover some of the details.
This is more of an 'in general' question. I'm not looking for information on the recent news. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/139ef8/eli5_the_us_and_why_israel_is_important_to_the_us/ | {
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"After the Holocaust in the 1930s-40s, it became clear that the Jewish people needed a homeland that could protect their culture and their people in the event that another group decided to attempt to exterminate them. Many began returning to their ancestral homelands near Jerusalem, which was part of a British colony known as Palestine. Because many of them began an armed revolt against the British control of the land, the US and Great Britain, under the auspices of the United Nations, carved out a piece of Palestine and set it aside as the Jewish homeland. Since it is a piece of land that was disputed for over a millennium, and was at the time occupied by Muslims, Israel has needed the military muscle of the US to back it in order to ensure it's existence. While the US has never officially become militarily involved in the Israeli-Palestinian conflict, we have been supplying the Israelis with armaments and other support for decades, at the same time attempting to broker peace between the two factions, with little success. \n\nSo one could say that the reason Israel is important to the US is because we created it. It's existence was intended to protect the Jewish people and culture and allow them the freedom to practice their religion which many other countries had denied them. Some Americans view Israel as part of the Christian faith, believing that the prophesied return of Jesus Christ will begin when all 12 tribes return to the holy land. Others simply believe that such a place needs to exist to protect the Jews. Still others believe that we need Israel to ensure that there is at least one friendly government in the region, since most of the others don't like America very much. Overall, it's an extremely complex issue that will probably never be solved to everyone's satisfaction.",
"Israel is our one friend who lives in the ghetto neighbor hood. were always being nice to them because when we visit them they are the only thing that keeps the rest of the ghetto from shooting us and leaving us in the ditch without our jordans."
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g6euo | Which (living) professor or scientist do you find most inspiring? | I've really become interested in psychology with the help of Paul Bloom from the Yale University, so he's been a real inspiration to me. Also V.S. Ramachandran helped me become interested in the human brain.
Who inspired you to become interested in science and/or is still inspiring you?
| askscience | http://www.reddit.com/r/askscience/comments/g6euo/which_living_professor_or_scientist_do_you_find/ | {
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"Robert Langer: _URL_0_\nOne of the most productive engineers in history.\n\nBrian Cox: _URL_1_\nAll around awesome guy who invokes the same kind of wonder about the universe as Carl Sagan did. ",
"You've got to respect Richard Lenski both for his amazing experiment and the way he dealt with the troglodytes who couldn't accept it.",
"RobotRollCall. Seriously.\n\nAs far as public personalities, a number of people inspired me to go back to school: Dean Kamen, Tyson, and Sagan.",
"E. O. Wilson.\n\nI've never met a man who can visualize ecological systems in such completeness and elegance. His work with ants goes beyond Ecology into the realm of philosophy, cognitive science, and even spirituality. To him, every study is an adventure into an uncharted world, and if you've ever heard him speak or even seen him in documentaries, you can see the wonder in his eyes.",
"Stephen Hawking, Neil de Grasse Tyson, and Brian Cox",
"I'll have to say Bill Gosper. He has a certain air of informality in his work, mixed with a little humor. Yet none of his results are \"smallest publishable units\". He's done groundbreaking work, and has a knack for finding beauty using often times little more than calculus -- much like Ramanujan.\n\nI'll also have to say Feynman (deceased). He also had an air of informality and humor, but also rocked the world of science. He smiled a lot too. :)",
"Richard Dawkins. He has an obvious passion for the truth, but maintains an appreciation for the beauty of the real world. I highly recommend Unweaving the Rainbow.",
"Yeah, Ramachandran is pretty cool.\n\nOthers... Hawking, Michio Kaku, Brian Cox...",
"Dr. Frink... blavin.",
"sir david attenborough devoted an entire career to bringing it to the people. Has done more to raising the scientific bar for nature programs than anyone I can think of. Promotes other peoples research incessantly. humble, hard-working and doesnt hype the way newer hosts do.",
"Stephen Hawking easily. Overcoming what he has while contributing so much is absolutely amazing.",
"For me it's definitely Neil deGrasse Tyson. His childlike exuberance about science is really appealing and it doesn't hurt that he has a great sense of humor. ",
"No mention of [Lawrence Krauss](_URL_0_) yet?\n\n",
"[Clifford Stoll!](_URL_0_) What a dork!",
"If you genuinely want to know what inspired me, as a kid, to go the science way.. then probably Commander Data and Captain Picard. ",
"So many good ones already, but nobody mentioned Hans Rosling. I love his TED talks!",
"[Bill Nye the Science Guy!](_URL_0_)",
"Oliver Sachs and Robert Sapolsky were really inspiring for me. They've written a lot of books which are accessible to non-neuro people.",
"[Donald Knuth](_URL_0_). While a graduate student in the 60s he started writing a [book](_URL_1_) about algorithms, and after the second volume came out he was not satisfied with how it looked. So he took 8 years and developed TeX, a typsetting program that revolutionized mathematical publications. He then resumed writing the book, which is not yet finished... \n\nAnother hero of mine is Prof. Chomsky, not only because of his political action, but also because part of his early [work](_URL_2_) is used every single day in computer science.",
"I'll second Paul Bloom actually, I've listened to the whole introductory course of his on academicearth and many of the things he mentioned and the way he explained them made me look further into the subject out of joyful curiosity, which is something the professors at my own uni don't happen to provoke all that often.",
"E.O. Wilson, Steven Pinker, Dawkins, James Kasting, Irene Pepperberg, Murray Gell-Mann, Francis Crick, Christof Koch, Razib Khan",
"[John B Goodenough](_URL_0_) \n\nhe will have a nobel prize. silly that he doesn't yet. ",
"No-one else love [Dan Dennett](_URL_0_)?\n\n[Consciousness Explained](_URL_1_) was a watershed in my school education. Literally inspired me into mathematical/computational neuroscience. Thanks Dan!"
]
} | []
| []
| [
[
"http://web.mit.edu/langerlab/langer.html",
"http://en.wikipedia.org/wiki/Brian_Cox_\\(physicist\\)"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://www.youtube.com/watch?v=7ImvlS8PLIo"
],
[
"http://www.youtube.com/watch?v=Gj8IA6xOpSk"
],
[],
[],
[
"http://www.youtube.com/watch?v=bU7t5bVfY4E"
],
[],
[
"http://en.wikipedia.org/wiki/Donald_Knuth",
"http://en.wikipedia.org/wiki/The_Art_of_Computer_Programming",
"http://en.wikipedia.org/wiki/Chomsky_hierarchy"
],
[],
[],
[
"http://en.wikipedia.org/wiki/John_B._Goodenough"
],
[
"http://en.wikipedia.org/wiki/Daniel_Dennett",
"http://en.wikipedia.org/wiki/Consciousness_Explained"
]
]
|
|
2u548b | how is tesla able to improve the efficiency or performance of their cars with over-the-air updates? | They seem to be constantly improving the range of their cars and Elon Musk just tweeted that the Model S P85D will be able go 0-60 mph ~0.1 sec faster with a new update. How is this possible? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2u548b/eli5_how_is_tesla_able_to_improve_the_efficiency/ | {
"a_id": [
"co58br7"
],
"score": [
3
],
"text": [
"It's the future, man. Nowadays, computers control every aspect of cars from running the engine to turning on the interior lights when you open the door. Electric motors are controlled by changing the voltage and current running to them. More voltage means more torque (twisting force) and more current means faster speed (less current is less speed). Engineers use complex equations to decide *when* to change the current and voltage that go to the motors, both of which combine to form the 'power' of the engine or battery. For example, there may be a lot of voltage when accelerating from a stop, but much less of it at a constant speed--these things are controlled by the computer. What Tesla has done is tweaked various variables inside the computer program that relate to how and when electricity is distributed to the wheel motors. The computer program(s) that control these things are updated over the air, just like your phone. By constantly modifying the programs that run on the Model S, the engineers can figure out what combinations of voltages and currents work best in different scenarios. Sometimes they completely change the program itself."
]
} | []
| []
| [
[]
]
|
|
34kjnh | I'm looking for video footage of 1919-1946 Germany, Can anyone help? |
I've recently become interested in World War II, and I'm looking for a website that allows one to download footage of Germany during 1919 to the aftermath of world war II (~1946).
However, most videos on youtube that have these videos either have annoying watermarks or names printed onto the video, or have been uploaded by neo-nazis and have distasteful music played with the audio.
Please respond with a link to a website which provides footage (preferably in colour) of the aforementioned time period. Since there isn't any copyright attached to these videos it shouldn't be hard, but I still can't find such a website unfortunately. Thanks everyone | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/34kjnh/im_looking_for_video_footage_of_19191946_germany/ | {
"a_id": [
"cqvpy11"
],
"score": [
2
],
"text": [
"You may want to look into ripping DVDs of classic german art films? \n\nedit: HA! I found it!\n\n I present to you, \"[Berlin: Symphony of a Great City](_URL_0_)\". It's basically just a sort of documentary of a generic day in Weimar-era Berlin (with some pro-socialist/communist imagery thrown in for good measure.) \n\nBut you want to know the best part? It's in the public domain and you can download it right now. Resoution kind of sucks, but it at least gives you a place to start?\n\nEdit 2: Something I should probably warn you about: this isn't an easy film to watch. It has almost no plot, no real characters, and this version does not include the score that is supposed to accompany the film.\n\nThat said, it's not just a collection of \"stuff happening.\" When Berlin was filmed, the idea of a montage--creating meaning by juxtoposing two scenes together--was very new, and the filmmakers use it quite a bit. The classic example is when a bunch of men going to work are juxtaposed with cattle."
]
} | []
| []
| [
[
"https://archive.org/details/BerlinSymphonyofaGreatCity"
]
]
|
|
aaz8s6 | If Romans relied upon local forces as auxiliaries, what language would be used on the battlefield? Were front-line soldiers required to learn Latin or were orders relayed through translators (and at what point in the chain)? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/aaz8s6/if_romans_relied_upon_local_forces_as_auxiliaries/ | {
"a_id": [
"eczbw40"
],
"score": [
3
],
"text": [
"In “The Middle East Under Rome,” Maurice Sartre discusses the concept of lingua-franca in the Mesopotamia and Anatolia. Although all high ranking Roman officials were asked to learn Latin, the majority of the known-world spoke Greek due to the Hellenization that occurred during the conquest of Alexander the Great and the Seleucid-Ptolemy war. So high ranking officials spoke Greek and Latin."
]
} | []
| []
| [
[]
]
|
||
5w2q23 | what is a social construct? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5w2q23/eli5_what_is_a_social_construct/ | {
"a_id": [
"de6uskr"
],
"score": [
17
],
"text": [
"Something that only exists solely because a bunch of humans agree it exists. Consider the value of cash, for example. A couple of sheets of cotton and some mostly zinc coins you have in your pocket aren't of much practical use to anyone. However, because we all agree they have value, they do."
]
} | []
| []
| [
[]
]
|
||
8ixq8p | how can lonely cloud survive in a crystal clear sky? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8ixq8p/eli5_how_can_lonely_cloud_survive_in_a_crystal/ | {
"a_id": [
"dyvei9e"
],
"score": [
4
],
"text": [
"In the absence of winds in the atmosphere, the \"lonely cloud\" would certainly dissipate. However, the rotation of the Earth and the different gradients of heating (of the soil and water) that the Sun causes, result in the atmosphere having currents of wind, and areas of higher and lower pressure and temperature. \n\nWater molecules stay in the air based on pressure and temperature. They condense to the fog droplets that you see as \"a cloud\" based on pressure and temperature. And rain condenses out of a cloud based on pressure and temperature.\n\nSo, basically, the \"lonely cloud\" is in a \"pocket\" of different pressure or temperature, bordered by winds (that you can't see) that keep it in that shape."
]
} | []
| []
| [
[]
]
|
||
2n5k42 | when holding hands, why does it feel so much better to be the "under" hand than the "over" hand (since neither position is actually ~~physically~~ uncomfortable)? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2n5k42/eli5_when_holding_hands_why_does_it_feel_so_much/ | {
"a_id": [
"cmaucji"
],
"score": [
2
],
"text": [
"Supposedly has to do with left and right brained. Which may or may not be a thing. For me the left thumb has to be over the right when I clasp my hands and its same for holding hands. There's a thing with preference in crossing your arms and a couple others. I'm a bad example b/c I'm evenly split on which side is dominant which is actually accurate b/c I'm analytical + creative\n. decent writer, good at math, play piano."
]
} | []
| []
| [
[]
]
|
||
1qbrc7 | how can uranium be used for "peaceful" purposes (as iran wants to do)? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qbrc7/eli5_how_can_uranium_be_used_for_peaceful/ | {
"a_id": [
"cdb7j9x"
],
"score": [
7
],
"text": [
"Uranium can be used to generate nuclear energy, which can be used as an alternative for fossil fuels to provide buildings with electricity."
]
} | []
| []
| [
[]
]
|
||
4yfkp7 | why do people become traumatized | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4yfkp7/eli5_why_do_people_become_traumatized/ | {
"a_id": [
"d6ndz39",
"d6nmz8s"
],
"score": [
16,
2
],
"text": [
"Your brain is a processing center that takes various stimuli and decides what to do with it. Say you're sorting toys into various bins and every time you pick a certain one up it gives you an electric shock and you drop it. It bothers you to leave it lying there when it should be sorted, but you can't get it into the right bin without getting shocked. Touching the toy causes trauma, and eventually even the thought of touching the toy will cause distress. That's what's going on in the head of someone with PTSD. ",
"The good guy always wins. The bad guy always loses. That's what we are taught by the United States Empire while they slaughter children in primal villages. \n\nI think people get traumatized because they figure \"this would never happen to me\" and take things like peace for granted. What would your reaction be if in 5 seconds somebody bursted in your house with a machete? That would never happen right? Just try to feel the energy from that possibility right now... it's weird even simulating it. \n\nWhen Aaron Schwartz killed himself I remember people saying it was because he \"never thought something like this would happen to someone like him\". When you look at the pure evil prosecutor involved in that case and the psychotic tendencies of our lettered organizations, I feel they exploited what they knew about Aaron to try to get him to crack which eventually resulted in his death, but either way part of him was in that \"how could this happen to me\" mindset. \n\nI have PTSD and honestly what really helped me was completely falling out of my comfort zone, going through a complete mental breakdown, then realizing that even though things go to shit they can come back together. I spent the last couple years almost homeless and barely eating, but eventually I humbled myself and changed a lot of bad habits. \n\nTLDR, people, including me, are sensitive pussies. There is nothing wrong with that. There are many things that I am bad ass at and it's not like I'm afraid of people, but when it comes to things like love I'm a sensitive pussy bitch. There are kids even today fighting wars at like 6 years old. They aren't as traumatized because they don't know what things like takeout or 401k's are.\n\n"
]
} | []
| []
| [
[],
[]
]
|
||
2u4z3c | How big of a problem was alcohol abuse/alcoholism in the Red Army during WW2? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2u4z3c/how_big_of_a_problem_was_alcohol_abusealcoholism/ | {
"a_id": [
"co5sc8u"
],
"score": [
10
],
"text": [
"The atrocious conduct of the Red Army following their conquest of Eastern Europe and East Germany was largely influenced by their blatant abuse of alcohol. In fact the NKVD allegedly reported back to Moscow complaining that 'mass poisoning from captured alcohol is taking place in occupied Germany' as it was seriously limiting their combat capabilities. Additionally, \"It seems as if Soviet soldiers needed alcoholic courage to attack women\". They were often so drunk they could not finish rapes, and in some cases used the bottle which caused devastating injuries (Antony Beevor, *Berlin*, 2007).\n\n\nIt should also be noted, compared to the other armies of World War Two, the Red Army's excessive drinking was linked to Russian culture:\n\n\n > [i]t was not the amount that Soviet soldiers drank that proved so disastrous for women - in comparion, for example to how much American soldiers drank - but rather the way they drank. As scholars of Russian drinking habits have repeatedly noted, Russians drink in binges, reaching a stage of intense intoxication over a period of several days, and they are quite sober before the next binge. The availability and high quality of alcohol available in Germany did not help the situation. One SDP informant recorded a hard and fast rule for dealing with Soviet troops: 'So long as he [the Russian soldier] is sober, one has almost nothing to fear Only under the influence of alcohol and also when several are drunk do the excesses begin' (Norman Naimark, *The Russians in Germany: A History of the Soviet Zone of Occupation, 1945–1949*, 1995).\n\n"
]
} | []
| []
| [
[]
]
|
||
i4thm | What are the bones that fuse together as we become adults? | Babies are born with 300 bones, and as they become adults the bone count goes down to 206. I know the skull fuses together, I'm just wondering what other bones fuse together? | askscience | http://www.reddit.com/r/askscience/comments/i4thm/what_are_the_bones_that_fuse_together_as_we/ | {
"a_id": [
"c20xc1e"
],
"score": [
7
],
"text": [
"This is kind of a misconception. It's not as if babies have more bones when they're born, it's just that bones aren't completely ossified at birth, so if you took an xray (for example) you'd see some areas where there were \"transparent\" areas in bones that aren't there as an adult. If we don't count each little island of ossification separately, and instead count the entire bony structure, including parts made of cartilage, infants and adults have the same number of bones (more or less).\n\nThat being said, major centers of ossification that often look like separate bones at birth are the skull, elbows, knees, hips, sacrum, coccyx, possibly some levels of the spine. You could really throw in any long bone as well, so you'd include some bones of the hands and feet, shoulders, etc."
]
} | []
| []
| [
[]
]
|
|
chhiii | Did America's founding father's engage in acts that would be considered to be terrorist actions? | I heard somewhere that America's founding fathers engaged in acts that would be considered terrorist actions, though I can't remember any examples being cited by the person that I heard it from. I was wondering if there was any actual evidence to support this or if my source was just making stuff up. | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/chhiii/did_americas_founding_fathers_engage_in_acts_that/ | {
"a_id": [
"euwm8eo"
],
"score": [
2
],
"text": [
"I would like to point out a quick note that things can get messy with terminology: as it was a ‘civil’ conflict at first, terms like ‘partisan group’ comes to mind. Then, after independence, anachronistic requisites would have it be that they were at war; I’d check out the letters between Germaine and Howe(authorized peace commissioner) to get a better idea of how the ‘rebels were viewed AT THAT TIME, both by the government and military of Britain. \n\nTerrorism is in many ways a very modern concept, even if the ideas behind it are old. Its a hard term to match to 18th century ideals, where rebellion and Nationalism was fomenting all across the world. \n\nWe can stretch it, especially with the Boston Tea Party; the patriots would tar and feather loyalists, which is certainly a ‘fear’ tactic. But at no point did the British consider them to be anything more than ‘rebels’ - again, check correspondence between parliament and colonial military government, and between the king. They thought of them as upstarts, a few scruffly backwoods rebels out to seize power for themselves. \n\nAs for the patriots? They saw their actions as justified(as did many in Britain). While their techniques could be brutal - vandalizing Tory homes, ostracizing families who didn’t support the cause, aforementioned tar and feather - they had a specific goal in mind: freedom. Today, ‘terrorist groups’ and ‘freedom fighters’ are often mixed in as one. Furthermore, in some sense, terrorism has been enabled by the proliferation of a globalized world. Terrorists know and exploit that. So it’s really difficult to ascribe a term so laden with modern connotation to something from the 18th century, though it’s not impossible to see the similarities."
]
} | []
| []
| [
[]
]
|
|
2k7ijc | why don't any of the american ebola patients have privacy dealing with their sickness? aren't patients supposed to have medical privacy? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2k7ijc/eli5_why_dont_any_of_the_american_ebola_patients/ | {
"a_id": [
"climdfp",
"clinwgq",
"clit14l",
"cliuvsh",
"clj2lpy",
"cljg0un"
],
"score": [
88,
28,
2,
2,
3,
2
],
"text": [
"The medical staff protect their privacy, news teams have no such inhibitions",
"The patients gave permission for the information to be released.",
"I suspect its more to do with mass panicking and people losing their shit.\n\nIts ok folks they been quarantines blah blah blah\n\nBlah",
"Some diseases, in the interest of public health, have to be disclosed to appointed governmental institutions. They usually are rare, dangerous and/or very contagious diseases. In Quebec they are called Maladies à déclaration obligatoire (\"mandatory disclosure diseases\" is the closest translation on top of my head). It is a legal obligation for physicians to advise the Health Ministry everytime they diagnose one of these diseases (I'm guessing the CDC would have the responsibility to keep records in the US...). The records are usually available to the public.\n\nI believe patient's confidentiality is still strictly protected. If a name is made public, then a consent must have been obtained.",
"What makes you think they don't? How do you know about the ones you don't know about?\n\n",
"[There is/was one patient who remained anonymous.](_URL_0_) So it's up to the patient to decide whether or not to give information to the media. "
]
} | []
| []
| [
[],
[],
[],
[],
[],
[
"http://www.washingtonpost.com/news/to-your-health/wp/2014/10/20/anonymous-ebola-patient-released-from-emory-after-being-declared-virus-free/"
]
]
|
||
9571t6 | how can hackers have more power in gta online than the makers of the game (rockstar) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9571t6/eli5_how_can_hackers_have_more_power_in_gta/ | {
"a_id": [
"e3qigo2"
],
"score": [
2
],
"text": [
"It's eather two things. One is that there is so much traffic that they can't find the hackers or they don't care enough to fix it."
]
} | []
| []
| [
[]
]
|
||
l0x7y | Given what we know about the human genome, how many genetically unique offspring is one pair of parents capable of producing? | I always find it incredible to think about the odds of my existence as a result of my ancestors reproducing with the right people at the right time. I was thinking about the odds of my parents producing a child with my genetic code as opposed to any other genetic combination. How many different potential offspring could a single pair of parents produce? Does genetic mutation allow for practically infinite number of possibilities? What if we ignored mutations for simplicity's sake? | askscience | http://www.reddit.com/r/askscience/comments/l0x7y/given_what_we_know_about_the_human_genome_how/ | {
"a_id": [
"c2ovchp",
"c2ovchp"
],
"score": [
7,
7
],
"text": [
"First, each parent has two copies of each chromosome they can give you. So already we are at \n\n 2^46, or 7 x 10^13\n\nNow let's add in crossing-over: \n\n[This paper](_URL_0_) states that oocytes have, on average, 70 crossovers, and spermatocytes have, on average, 50 crossovers\n\nSo let's simplify and say all humans have 120 crossovers in the gametes that go on to form them.\n\nHow many unique combinations can 120 crossovers produce?\n\nWe have to make another simplification here. Let's say that crossovers can occur at any place on the genome. That means there are 3 billion potential places for crossover to occur. The number of unique crossovers is therefore the ways you can pick 3 billion things, choosing 120 at a time, or:\n\n 3,000,000,000 C 120\n\nWhich is 2.6 x 10^938.\n\nAdding in our 23 chromosomes from earlier, we get **1.9 x 10^952 ** . Which is a really big number.\n\nNOTE: Many of these unique genotypes will be phenotypically identical. Much of the genome is for non-coding regions, etc.\n",
"First, each parent has two copies of each chromosome they can give you. So already we are at \n\n 2^46, or 7 x 10^13\n\nNow let's add in crossing-over: \n\n[This paper](_URL_0_) states that oocytes have, on average, 70 crossovers, and spermatocytes have, on average, 50 crossovers\n\nSo let's simplify and say all humans have 120 crossovers in the gametes that go on to form them.\n\nHow many unique combinations can 120 crossovers produce?\n\nWe have to make another simplification here. Let's say that crossovers can occur at any place on the genome. That means there are 3 billion potential places for crossover to occur. The number of unique crossovers is therefore the ways you can pick 3 billion things, choosing 120 at a time, or:\n\n 3,000,000,000 C 120\n\nWhich is 2.6 x 10^938.\n\nAdding in our 23 chromosomes from earlier, we get **1.9 x 10^952 ** . Which is a really big number.\n\nNOTE: Many of these unique genotypes will be phenotypically identical. Much of the genome is for non-coding regions, etc.\n"
]
} | []
| []
| [
[
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC379134/?tool=pubmed"
],
[
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC379134/?tool=pubmed"
]
]
|
|
4ns8vc | what exactly makes sunlight hot on a nice sunny day? is it the temperature of the sun itself radiating through space or some form of refraction of the light itself? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ns8vc/eli5_what_exactly_makes_sunlight_hot_on_a_nice/ | {
"a_id": [
"d46hgqg"
],
"score": [
3
],
"text": [
"Sunlight hitting the atmosphere is always the same.\n\nIt's local weather conditions that change. Warm dry conditions, open sky, the sun is going to continue to warm up the already warm air. Warmth (or lack of) from previous days is stored in the ground and water and moves across the area in pressure systems."
]
} | []
| []
| [
[]
]
|
||
1ao7hy | Is it possible to explain magnetic fields in terms of electric fields? | For example, a current carrying wire will generate a magnetic field, which will exert a force an any moving electrons in the vicinity. Can this be explained by electric forces alone? | askscience | http://www.reddit.com/r/askscience/comments/1ao7hy/is_it_possible_to_explain_magnetic_fields_in/ | {
"a_id": [
"c8z7k33",
"c8zb7aj"
],
"score": [
2,
5
],
"text": [
"The way I understood it from my E & M class was that magnetic fields are Lorentz transformed electric fields. There was a cool illustration in the book showing how the spherical electric field gets squashed into an ellipsoidal shape when a charge moves, and somehow this exposes the electric field to other moving charges in such a way as they behave as if being influenced by magnetic fields.",
"Yes, but it requires a pretty solid understanding of relativity. Imagine two long string of charges, one with charge per unit length +Q/L, one with charge per unit length -Q/L. Lets say that these string of charges are right on top of one another and moving in opposite directions with velocities +v and -v. Because they move in opposite directions, there is a net current (remember, current is defined as positive flow, so negative charges moving in the -v direction constitutes a current in the +v direction).\nThere is a charged particle moving in the vicinity of this wire with speed u.\n\n To a stationary observer, there is no electric force on the moving charged particle because the electric fields due to the two strings of charges at this point are equal and opposite. Let's look at things from the perspective of the charged particle. Using the [velocity addition formula] (_URL_0_), we find that the -Q line is now moving *faster* than the +Q line. \n\n-Q: v = u - v / (1 - uv/c^2 )\n\n+Q: v = u + v / (1 + uv/c^2 )\n\nBecause the speed of the negative line charge is greater, the spacing between the charges will decrease due to greater Lorentz contraction. Because the spacing between the charges is less, the charge per unit length increases, which means that in the frame of the moving charge, the \"wire\" has a *net negative charge*, and will feel an electric force. There's a bunch of algebra I'm too lazy do to prove that this electric force is equal to the magnetic force exerted on the charge in the rest frame."
]
} | []
| []
| [
[],
[
"http://en.wikipedia.org/wiki/Velocity-addition_formula#Special_theory_of_relativity"
]
]
|
|
2kawc7 | If you have a cold container (soda, water, etc.) and you place it in front of a fan, is it being cooled more/kept the same temperature by the fan or is it being warmed up faster? | askscience | http://www.reddit.com/r/askscience/comments/2kawc7/if_you_have_a_cold_container_soda_water_etc_and/ | {
"a_id": [
"cljke5t",
"cljl4m4"
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"score": [
9,
3
],
"text": [
"A fan moves air, and heats it up slightly because the fan itself is hot. More air passes over the container due to being the target of the fan, so the container will become the temperature of the air more quickly. If the air is a lower temperature than the container, the container will cool down. If the air is a higher temperature than the container, the container will heat up.",
"It depends on a lot of variables. Fans don't cool the air, you feel cooler often via evaporation (look up \"swamp cooler\" for more on this) so if the item is wet and the humidity/pressure is right, and the temp of the item is high enough in relation to the surroundings, it will continue to cool till dry...ish. lol. A lot of variables come into play. \n\nIf it's dry and the ambient air temp is higher than the item and the air is going at a rate that increases contact/air friction and doesn't create a slip stream situation, it will increase the rate at which it warms compared to being left in the same environment with no significant air movement. "
]
} | []
| []
| [
[],
[]
]
|
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