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2qj8e4 | what ever happened to puerto rico becoming a sate? the voted for it--now what do they need to do? | Outside of final congressional approval, what do they need to do first to actually become a state, since they voted a couple of years ago saying it is what they would like to do? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2qj8e4/eli5what_ever_happened_to_puerto_rico_becoming_a/ | {
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"Currently it's debatable where they actually voted *for* statehood. The only thing that's clear is that the majority voted *against* staying a territory.\n\nOf that majority, many did vote for statehood, but many of the minority (stay a territory) voters left the \"what should we change to\" question blank. Some argue that interpreting the results as pro-statehood isn't accurate because of this weird division of the question.\n\nThere have been talks of having another referendum that basically asks \"Do you want to be a state? yes/no\"",
"I think Congessional approval is the only hurdle left. Two bills have introduced, one in the senate and one in the house of representatives. We will probably have an idea by the end of 2015 what the outcome of their statehood will be.",
"The actuall issue is politics. PR would be a very heavy democrat stronghold. No way republicans will allow that unless you can find another territory, equally republican leaning, to balance it out. "
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7vwc63 | how do magnetic ipad covers lock/unlock the ipad when it’s closed/opened? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7vwc63/eli5_how_do_magnetic_ipad_covers_lockunlock_the/ | {
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"There's a sensor inside the iPad that the magnet triggers. The sensor puts the iPad to sleep or wakes it up.",
"Magnets in the Smart Cover trigger magnetic switches in the iPad that sleep/wake the device. ",
"It basically uses the 'Hall effect' phenomenon. Your iPads/phones have a sensor which when it comes in the field of a magnet turn the screen off and turn it back on when there is no magnetic field interference."
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6qt8vq | I'm a regular person living in France as the Nazis invade and take the country. How does my day-to-day life change? | How does the operation of the country run? Does everyone still go to work every day, pay taxes etc. What happens to the government? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/6qt8vq/im_a_regular_person_living_in_france_as_the_nazis/ | {
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"**Part 1**\n\nThis of course, depends strongly on when we are talking about, if it concerns the time frame directly after the French collapse in 1940 or the stretch of time when the Vichy Regime ruled the southern parts of France or after the German occupation of all of France in 1942. And there is also the distinction between urban and rural settings in terms of how they were affected by Nazi invasion and occupation.\n\nFor some important context: The fall of France in June 1940 was a shock to its population. Massive volumes on the background behind why France fell have been written and while some important factors were military ones, others concern the state or morale in France and the trauma of WWI. While all this has historical importance, in terms of how everyday life changed, a highly important factor is that the war of 1940 was the least destructive war fought on French soil in the 20th century. French cities had not been systematically bombed as Rotterdam and Warsaw had been and London and Belgrade were about to be. Neither had wide areas of French soil been reduced to no-man's-land as it had been from 1914 to 1918.\n\nThis would change later when through Allied bombing and Operation Overlord France would become the second most bombed country on the Western Front after Germany but for the beginning of occupation and the change in regime, this lack of destruction is significant in as far as it enabled both the occupying Germans as well as the Vichy Regime that agreed to sign the armistice with the Germans to implement a policy of stressing a quick return to normalcy in order to prevent chaos as well as resistance.\n\nThis policy was ever present from the German side during the war. Take for example [this article from the Observer from 1941](_URL_0_) re-published in the Guardian:\n\n > The interesting thing is the immense care that is taken to please the French people and to show that German and French culture are not only essentially harmonious, but are complementary to each other. \"Collaboration\" is the daily theme, profuse flattery being addressed to the French businesses represented at the Leipzig fair, to the France Européenne exhibition, to the French banking system, to the particular French political and economic gifts that could play their part in the new Europe. There are glowing articles about Paris, its monuments, places of historic interest, its cafes, gaiety, charm, its bread, its women. \"The beauty of Paris is that she is really like an impressionist painting,\" ran one typical sentence in a recent article.\n > \n > Nightclubs are praised and advertised. The suggestion is implied that Paris, with its historical, cultural and entertainment value, is to become the chief centre of recreation and relaxation for the German overlords of the future, and that France will thereby be contributing a valuable part in the future working of the New Order in Europe.\n > \n > The emphasis that is laid on the life of Paris during the period of military occupation is designed to show that French cultural life is flourishing as impressively as before the occupation. French singers are given objective praise as artists. French authors, playwrights and actors are encouraged. The French film industry, suppressed in the early days of the occupation, is now resuscitated and encouraged, whereby the German authorities indirectly claim credit as the rebuilders of French cultural life.\n\nAnd they weren't the only ones. The Vichy Regime under the leadership of Marshal Pétain was from its very beginning more interested in restoring order in civil life out of considerations for their own power as well as for unproblematic collaboration with the Germans. As Robert Paxton describes in his standard work on Vichy, for them, chaos was something to be prevented instead of exploited as the ultimate weapon against Hitler. Pétain as early as June 13 (one day before the German occupation of Paris) advocated for the \"natural defenders of France\" by which he meant administrative carapace of France, from ministry down through prefect to village mayor, and of course army and police. The personnel of these agencies made it a matter of professional honor to serve. The new regime was the lawful successor to the old and there was work to be done. The state itself was regarded as a positive good in itself and thus had to keep running.\n\nAnd this civil servants' sense of the state was reinforced by a general thirst for normalcy in the summer of 1940. During the time of the immediate aftermath of the shock of defeat, the establishment of the German occupation and especially the shortages that came with occupation, most people were immediately concern with a sort of day-to-day survival and with putting their lives back together.\n\nTake for example Simon de Beauvoir describing how she hitchhiked back to Paris in July 1940: \"For three weeks now I have been in a sort of limbo: vast public events brought their own individual, physiological agony, but I wanted to become a person again, with a past and a future of my own. Perhaps here in Paris I shall achieve this aim. If I can draw my salary, I shall stay for a long time.\" As Paxton writes:\n\n > Nearly everyone tried to get normal life going again. Refugees made their way home or sought shelter in a safer place. Families tried to get in touch. Around two million young Frenchmen in prisoner-of-war camps on French soil anxiously awaited release. A flood of job applicants wrote to Marshal Pétain. Alarmed at the level of unemployment, French economic officals worked to revive the economy. Businessmen turned to German Army contracts. (...) The most elementary prompting of normalcy in the summer of 1940, the urge to return to home and job, started many Frenchmen down a path of everyday complicity that led gradually and eventually to active assistance to German measures undreamed of in 1940. Delivering mail, repairing bridges, teaching schools, relocating refugess – everything that restored France to tranquility and order fulfilled the tacit Franco-German bargain to withdraw France form the war, socially intact, and to turn her engines inward.\n\nBut despite this massive political and social desire to return to a semblance of normalcy, the German occupation changed every-day life in many an impact-full way: Paris e.g. experienced a demographic change. Host to 40.000 German soldiers and the hotspot for German soldiers of the Wehrmacht to spend R & R time, the city was flooded with daily reminders of the occupier. And the occupier had money. German soldiers receiving special occupation money upon entering the country could spend said money, which functioned like a requisitioning paper, on things that many of them could have never have afforded before the war. Many an account of a war-time Parisian strongly features the \"doryphores\" (potato beetles) as the Germans were commonly known. In their letters home Wehrmacht soldiers reported their findings and asked their families fro more money to buy even more. And they bough everything. An ordinary private named Böll send home: four kg of Coco, a pound of butter, a kg of soap, several hundred sheets of fine paper for letters, French-made lace underwear, shoes, cosmetics, three kg of sugar, one kg of coffee, cheese, chocolate, and a fine par of calf leather motorcycle gloves. This happened to some degree with more than ten thousand German soldiers who visited France every month.\n\nOne of the far-reaching consequences of this behavior as well as the official German economic policy in France was the experience of shortages, rationing and the necessity of the black market for the ordinary French citizen. This problem was further compounded by the wage controls that the Germans introduced while at the same time causing inflation though the above mentioned behavior and the introduction of occupation money.\n\nRationing started fairly early: Beginning in August 1940, each citizen registered with their local suppliers – butchers, bakers, etc. This registration was then noted on a citywide level and ration cards were made available periodically, usually on a monthly basis, in the mairie, or town hall. A ration card determined how much of a type of food – in pounds of meat, for example – a person was allotted each week. The Germans were not interested in needlessly antagonizing the French, so food allotments were not intended to starve the local population. Nonetheless, hunger has been pointed to as perhaps the predominant feature of the Occupation since rationing simply could not meet demand.\n\nIn consequence, many a French citizen turned to alternative means in the black market, which became quite extensive quite quick. The countryside played the crucial role of supplier for the cities, supplementing the diet of town and city dwellers throughout the nation. This took place in a number of ways and one of the most immediate ones was the family. This often led to urbanites rediscovering country cousins who could provide them with much needed packages of food. These packages were known as colis familiaux. In 1942 alone, 13.5 million were mailed throughout France. Often this smaller market, sometimes called the marche amical, was based on barter economics, or even in some cases on the promise of future payment.\n\nBut the black market took on more forms, and beyond the immediate family was a massive opportunity for those in positions to exploit it. Crime in general spiked during the occupation and most notorious probably were the faux policiers, literally fake policemen, who were either policemen off the clock or other people who had acquired police uniforms and used them to extort bribes from people, requisite their food and belongings and prayed on shop owners and Jews especially.\n\n\n\n\n\n\n\n"
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3qt0u6 | Were any high ranking Axis personel killed in Allied Air Raids? | The mass aerial bombing of Germany and Japan targeted their major cities and killed hundreds of thousands of civilians, but did these air raids ever manage to kill any important Axis personnel? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3qt0u6/were_any_high_ranking_axis_personel_killed_in/ | {
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"Very few — in fact, the only one that immediately comes to mind is [Roland Freisler](_URL_0_), the judge-president of the People's Court, who died in a raid in February 1945. But the objective of mass strategic bombing (on both sides) during the war wasn't really to decapitate enemy leadership — it was to attack economic and industrial infrastructure and undermine civilian morale."
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rkls3 | If someone pointed a gun against your forehead and fired, would you even know they pulled the trigger? | Would your neurons signal to your brain before the bullet?
Edit: Just wanted to clear things up, I am NOT suicidal. I'm a perfectly content college student, happy with the fact that everything I need in life has been put in front of me over the years. I just thought of this last night when I couldn't sleep and I had remembered a clip from a WWII movie where Hitler walked into a group of people at a camp and just shot 6 of the in the head.
And also, I didn't realize this thread would end in a barrage of internal downvotes. I just knew from [this](_URL_0_) game that you have a reaction time for everything (well technically this is from different stimuli to the brain and back to the periphery), so I was curious if you were unaware of when the trigger was pulled if someone who was not yourself (you'd be consciously aware) were the shooter. | askscience | http://www.reddit.com/r/askscience/comments/rkls3/if_someone_pointed_a_gun_against_your_forehead/ | {
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"Considering that bullets will go supersonic, the sound might not reach your ears before the bullet hits your brain. However, I don't know how fast the bullet accelerates before meeting the muzzle. Still, even if the sound reaches your ears, humans on average have around a .150 second reaction time to auditory stimulus. The bullet will definitely reach your brain before 0.150 seconds are up.\n\nSo assuming that the shot is an instantaneous kill shot, you wouldn't know.\n\nHowever, another interesting thing to point out is that not all bullet v head shots will kill. As a general rule, if you avoid hitting any major arteries on the way through, there's a possibility you can survive such an event. ",
"There was a documentary on the discovery channel about people who attempted suicide with firearms and survived. One lady shot herself in the head with a revolver and was discovered a few minutes later by her husband. She was able to tell him \"I don't want to die.\"\n\nShe recalls not hearing anything but feeling a very intense and sharp pain and then nothing/blackness.",
" > a clip from a WWII movie where Hitler walked into a group of people at a camp and just shot 6 of the in the head.\n\nThis must have been a fictional movie. To my knowledge, Hitler never personally killed anyone other than himself and possibly Eva Braun. Even in WWI he was in the artillery, and was basically a messenger.",
"I know shit all about bullet ballistics etc. But no-one here is taking the following factors into account:\nYou would know they pulled the trigger not just from the sound of the bullet, but from the sound of the click. There is a time between the clicking of the trigger and the propulsion of the bullet.\nAlso the muzzle flash would occur before the bullet travels to the head, and light is a lot faster than sound."
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353fds | In the history of US intervention, has a military or financial investment in another country paid off? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/353fds/in_the_history_of_us_intervention_has_a_military/ | {
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"What do you mean by \"financial investment\"? Are we talking the US government helping prop up a foreign government's spending, funding development projects, or what?\n\nAlso, what counts as an \"intervention\" for your purposes?",
"Absolutely: Panama Canal. And in terms of level of intervention, I think it's fair to say that the U.S. has almost never interfered/intervened with the affairs of another country quite so thoroughly. Bold claim? Sure. But the facts back it up.\n \nFirst, consider that the U.S. potentially ginned up the Panama City revolution, and at a bare minimum, U.S. military support on November 3, 1903 was critical to the survival of the revolution. The U.S. consolidated those gains three weeks later with the Hay–Bunau-Varilla Treaty, which gave the U.S. precisely what the Columbians had previously refused to grant: permission to own, operate, and profit from a completed canal. So there's the military investment: through the hard work of the USS Nashville and the Marines on board, the U.S. won with military pressure something they hadn't been able to accomplish diplomatically.\n \nNext came the financial investment, which obviously was substantial. The all-in cost for the U.S. was almost $400M in contemporary dollars (i.e., not adjusted for inflation). I've never been able to find a good figure for total tolls paid, but in some senses that's irrelevant when deciding whether the investment \"paid off.\" Through two World Wars and a Cold War, the U.S. controlled the Canal. Our ships, both military and civilian, and the ships of our allies, had full use of the canal, and our enemies' ships did not. The commercial and military advantages were amazing. And the investment paid substantial knock-on benefits: the Gulf Coast port towns in the U.S. saw a substantial increase in shipping tonnage due to the Canal, and those ports took economic opportunities away from developing ports in South and Central American which could have served as coaling/refueling stations if ships had continued to round the Cape.\n \nAn absolutely awesome source for all things Canal related is The Path Between the Seas by David McCullough. In addition to being a fascinating topic (or so I think), the book is also extremely well-written.",
"The korean war and subsequent support for the south korean regime have at a relatively low cost provided the US with a very strong military ally in east asia and a major trade partner \n\n\nRichard miller estimates the cost of the korean war as 678 billion 2007 dollars \n\nWhile according to the US trade representarive bilateral trade with South Korea was 113 billion dollars in 2014 alone \n\nWhen you factor in the strategic and military benefits its pretty clear korea was a good investment"
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2mau9j | Book List in Wiki Question -- Looking for suggestions on Financial History. | I am looking to learn more in regards to financial history / history of money (an example would be *The Ascent of Mone*y by Niall Ferguson or *The Battle of Bretton Woods* by Benn Steil) and did not see a financial history category in the wiki book list.
Does anyone have any suggestions? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2mau9j/book_list_in_wiki_question_looking_for/ | {
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"*Friedman/Schwartz, A Monetary History of the United States, 1867-1960* is probably more technical than what you are thinking of but a seminal work and well worth a read."
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uym0s | Can food allergies be overcome? | I've heard from several people before (non-scientists) that introducing a tiny tiny amount of what a person is allergic to back in to their system and very gradually building up the dosage is enough to cure an allergy.
Is this true, either in some cases or as a universal cure? | askscience | http://www.reddit.com/r/askscience/comments/uym0s/can_food_allergies_be_overcome/ | {
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"Scientists have, in fact, done this with various things.\n\nExample: [peanuts](_URL_0_) (the study mentioned in this article was reported on in 2010).\n\n > In a recent experiment presented at the February meeting of the American Association for the Advancement of Science, Andrew Clark of Cambridge University recruited 23 peanut-allergic children and fed them precise doses of crushed peanuts every day. At first they showed the typical allergic reactions: lots of itching, coughing and reddening of the skin. But after just three months, most of the kids were able to eat five peanuts a day with no reaction; at the end of year, the majority of them could safely eat 32 peanuts, which meant they no longer needed to read food labels for possible nut contamination.\n\nNote that they start at incredibly small levels:\n\n > \"We start at the microgram level, scale up to milligrams and may end with grams [of peanuts],\"\n\nI don't see it in this article, but when I first read about this a couple years ago, I remember reading that the treated kids actually had to eat peanuts every day to maintain their new allergy freedom. So basically, the kids were prescribed a daily dose of peanuts (about 5 if I remember correctly). If they stopped eating peanuts, their allergy would return to previous sensitivities.\n\nHowever, we definitely can't say at this point that this approach would work for everyone. We also can't say it would work for every allergy. And the original research paper specifically recommends people do not try this themselves at home. The initial doses have to be incredibly small, and it's very hard work getting to a level that will not trigger a lethal reaction, but will be high enough to start to desensitize the body. And it also mentions that the patients all exhibited allergic reactions each time the dose was increased, and they had to be monitored closely to make sure the reaction wasn't too strong. \n\nSo basically, don't try this at home, and as always, don't treat any of this as medical advice."
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b57kp1 | Why do black holes have such strong gravitational fields ? | They are formed from a collapsed star core right?
I always thought gravitational fields depended on mass not density, why doesn't this work for black holes? | askscience | https://www.reddit.com/r/askscience/comments/b57kp1/why_do_black_holes_have_such_strong_gravitational/ | {
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"You're absolutely right: if you replaced the Sun with a black hole of the same mass, the Earth would continue in exactly the same orbit.\n\nThere are two things that make a black hole a bit different though.\n\nOne is that black holes are *really small*. With something like the Earth, gravity is stronger as you get closer to the planet - it depends on the mass of Earth and your distance from Earth. But if you start digging down into the Earth, gravity starts to get weaker. Not all of the mass is \"beneath\" you now - a lot of it is above you - and this means gravity is pulling you in two directions, cancelling itself out a little. So gravity gets *weaker* as you dig downwards, and reaches zero at the centre of the Earth.\n\nBut a black hole is really small - for a non-rotating black hole, the mass is in a single point really. So, instead of the gravity getting weaker as you enter the Sun, you have gravity just continually increasing until you reach the point where it's so strong that light can't escape. This happens when you're about 3km away from the centre of the black hole, which is really quite small.\n\nThe other thing is that nothing can escape from a black hole, which means that they can just continue to grow in mass forever (excluding very weak effects like Hawking radiation). For stars, the more mass they have, the faster they burn, and the more quickly they will go supernova and explode. You can't just keep on adding mass to a star - it's an active system that goes through reactions and spits out mass too. But with a black hole, there's nothing stopping you from adding more and more mass until you get a black hole that's over a *millions* times the mass of the Sun. We have detected these super-massive black holes in the centres of galaxies, including our own.\n\n**tl;dr:** Black holes are so tiny that you can get close enough to them that the gravity gets extremely strong. Some can also grow indefinitely and become incredibly massive - far more massive than any star could be.",
"They don't. If our sun was suddenly crushed to a black hole of 1 solar mass, Earth's orbit would be entirely unaffected. Hollywood and pop culture has some strange idea that black holes are like magical sucking machines or something. That's false. As you say, a spherical mass of mass M has exactly the same gravitational pull as a black hole of mass M at a distance.",
"The strength of gravity *greatly* increases as the distance between you and the object decreases.\n\nOther answers talk about the Sun's mass and the gravity at the Earth's distance. It would be the exact same strength.\n\nSo let's try getting closer to the former Sun. Say we stop at where the Sun's surface **used** to be. The mass hasn't changed, and the distance is the same as the old surface distance. So the gravity here should be the same strength as it was at the surface of the old Sun.\n\nBut the thing about black holes is that they contain all their mass in an incredibly dense point. Meaning they take up much (much) less space than before. The Sun used to have a radius of nearly 700,000 kilometers. That's as close as you could get to the Sun. You hit the surface and that's the max amount of gravity you could feel.\n\nBut now that it's a black hole, we can go much closer than that. And because there's no surface to hit, we can go as close as we want.\n\nAs I said at the beginning, the strength of gravity goes up a lot as distance shrinks.\n\nThis is where the strong gravity occurs. Inside of the previous distance limit. That's why density is important, it allows us to get much closer to the center of gravity than before."
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g3t9yl | Do antibody test detect memory B cells after active anti bodies have subsided? | From what I understand, antibodies are only present in the body during the infection (and remain in the body for about 2 weeks post infection). After the infection (or virus) has been defeated the anti bodies leave and memory B cells take their place.
So how do antibody tests work? Wouldn’t they be effectively ineffective after the antibodies leave? Or are they able to detect the presence of memory B cells?
I’m specifically thinking of how the COVID-19 antibody test would work to identify folks who have had it in the past.
Cheers in advance folks | askscience | https://www.reddit.com/r/askscience/comments/g3t9yl/do_antibody_test_detect_memory_b_cells_after/ | {
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"B cells undergo selection and receptor editing in a process called the Germinal Center Reaction. Most of the B cells involved die off, but the ones that are left in theory are able to produce the best immunoglobulin of the appropriate class. Upon exiting the germinal center, these cells either differentiate into memory B cells, like you mentioned, or into plasma cells which constantly produce that antibody. A subpopulation of these can be long lived and self-renewing. \n\nThese long lived plasma cells are why antibodies against a past infection or vaccine can be found in the blood for years and in some cases decades after the initiating event even though the half life of an antibody in the blood is somewhere between 5 days and 3 weeks, depending on the class and concentration. There is no good explanation why some infections/vaccines result in long lived immunity, and why some are relatively quickly forgotten."
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2t2jbf | why do people say you can't get rid of something once it's on the internet and that our digital footprint will outlive us all, when a lot of times even just a 4 or 5 year old page can be impossible to track down? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2t2jbf/eli5_why_do_people_say_you_cant_get_rid_of/ | {
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"Because the first person to see something can copy it, screenshot it, and rehost it, and oftentimes, things that you host and then \"delete\" are not immediately removed from the host, just hidden from other people. ",
"impossible to track down, buddy everything is archived I can view how reddit looked 2 years and 3 days ago in 10 seconds if i wanted to."
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3z252c | how were bank robbers in the old west (1850-1870) caught or chased? | If there was someone who went around robbing banks in the old west, would it be the police/marshals who chased him or would it be someone else? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3z252c/eli5_how_were_bank_robbers_in_the_old_west/ | {
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"If the robbers were local the local police would go after them. If they covered a lot of area the US Marshals and the Pinkerton detectives would look for them. Wanted posters would go out so local law enforcement in other areas would keep an eye out for the robbers. ",
"Well by the 1840s, a lot of the larger cities (Boston, etc)had implemented a police force. Out west wasn't very different. They had either U.S. Marshals, Sherrifs, Texas Rangers, Constables, and Deputes. These folks would be the ones to go after the bank robbers using various methods such as posting bounties, wanted posters, etc. However anyone with the balls could apprehend or take out the criminals and get their reward with little to no consequences. Maybe a handshake and a thanks. Nowadays it's of course considered vigilantism and the would be heros would be prosecuted instead. "
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34vb2t | what is really the difference in gas types? | What is the real difference in levels of gasoline? And also, what is the difference between gasoline and diesel?
Is it just quality? Or an excuse to charge you more?
EDIT: Wow, thanks a bunch. Makes sense, | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/34vb2t/eli5what_is_really_the_difference_in_gas_types/ | {
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"Octane levels and compression rates. Regular gas combusts at lower compressions (your average car). Premium gas combusts at higher pressures (most sports cars). A higher pressure combustion creates more energy which is why it's used in sports cars. There's absolutely no benefit of putting premium gas in a car designed for regular and can actually be detrimental. Same goes for putting regular in a car designed for premium.",
"Gasoline contains a number of different carbon compounds. These usually range from Pentane (5 carbons) to Octane (8 carbons). High octane fuels have more octane in them; this means that they burn slower because larger carbon compounds tend to burn more slowly. This is actually beneficial to engines, because if the fuel burns too fast it can harm engines. Diesel contains larger carbon compounds, usually somewhere in the teens. ",
"Higher octane gas is more resistant to igniting. Or, to put it another way, it \"burns hotter,\" that is, the higher the octane, the higher the temperature it can attain before exploding. That's why it can withstand more compression. The \"ping\" from putting low octane in cars requiring mid grade or premium comes from the lower grade fuel igniting a split second before it's supposed to -- which makes it fight the piston, which is still traveling up on the compression cycle (ouch, poor engine). Modern engines have ways around this but you'll suffer a horsepower loss with too low an octane. Diesel engines have much much higher compression rates than normal gasoline (about 22:1 as opposed to 10:1). So diesel fuel is much more resistant to igniting on its own. Diesel engines do not have spark plugs to ignite the fuel. It explodes on its own when the high compression level is reached."
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2ng3db | if music is playing in my head when i go to sleep, the same song/track instantly resumes playing as i wake up. why? | This has always fascinated me. I'm wondering if like some parts of your brain just stores whatever info is circulating as I fall asleep in it and resumes as it wakes up? Or is the song just non stop playing in my head as I sleep? What goes on in my brain while that happens?
Or is this just unique to me? My family has always been heavy on music. Grand parents are conductors, almost all family members musicians on some instrument, or sing in choirs ect. so that may have something to do with it I could guess. Do similar thoughts resume for other people who are enthusiastic about other subjects possibly? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ng3db/eli5_if_music_is_playing_in_my_head_when_i_go_to/ | {
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"Probably mostly conformational bias - mixed with the fact that your memory of things before sleep is poorly coded.\n\nSo conformational bias means you only notice when the pattern is reinforced and place little value on when it doesn't.\nEg. You were listening thinking of a track before bed but you woke up and didn't have that song so you have no reason to think \"hey did I have a song stuck in my head last night???\" - instead you just ignore this case.\n\nThen after a few times in a row of waking up with a song in your head - you think you noticed a pattern. So you develop a habit of thinking in the morning: Hey do I have a song in my head - which causes a song to play in your head, likely the same on from last night. Thus reaffirming your bias.\n\nThis coupled with the fact that there is a 15min window in which you are not really awake nor asleep yet, and the things going through your mind may seem like a waking mind but they are not coded like proper memories. So you might have had a few songs in your head - but you're only going to remember the one that matches up with the song you have in the morning, because of the way those thoughts are coded.\n\nLastly - you brain does not just \"resume\" when you wake up. Sleep is terribly complicated and poorly understood but simply put, your brain does more asleep than it does awake."
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36q8s5 | why is there a market for commodities trading? | I'm trying to understand the very basics of the commodities market, especially agri commodities. I am not entirely sure I understand why the trading happens at all. Some of the questions I have are:
1. What are the origins of the commodities market?
2. Why do commodity exchanges exist?
3. Why do people trade on spot and futures (and why is this allowed) without taking actual delivery of the commodities?
4. Where do traders come into the picture? Why isn't it a simple chain from the producer to the end customer with middlemen (wholesalers, distributors, dealers) in between?
I've tried to understand this from Google searches and past Reddit posts. But all of them seem to deal with more in-depth topics. Could someone please explain like I am 5? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/36q8s5/eli5_why_is_there_a_market_for_commodities_trading/ | {
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"Let's take a very simplified example.\n\nYou're a hog farmer. The pigs you raise, take 1 year from birth to slaughter time. So on January 1 2015. You want to buy 5000 baby pigs. You buy the baby pigs from a breeder, and you spend a year giving the pigs medication, hormones and feed. \n\nOn December 31, when you take the pigs to the slaughter house, the slaughter house tells you the current price for the hogs. What the farmer assumed he'd get a different price, and spent more money on medication and food? Now he might lose money, instead of making it. Plus the farmer had to use his savings to pay for the hogs all year long. \n\nInstead what if the farmer promised to deliver 4500 hogs on Dec 31, of a certain age and weight to the slaughter house for a certain price. In exchange for that, the slaughter house gave the farmer some money now that he can use to buy baby pigs, and raise them.\n\nThat is what a futures contract, or a commodity contract is. Now what if the slaughter house decides, they will get too many hogs on December 31 and want to sell the contract to someone else. Maybe another slaughter house might buy it. Maybe a middle man (a trader) might buy it.\n\nWith out the middleman or trader, it might be very difficult to find a buyer of a futures contract.\n\nIn general, spot traders are the people who can take delivery. Spot contracts have delivery contracts of a few hours to few days. Where as futures contracts might have delivery several months from now."
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4qzw6q | Why does adrenaline make you stop feeling injuries? | Today, I read a few posts in an /r/askreddit thread that told how they did not feel their very major injuries (broken back and hip) until they woke up later in a hospital bed.
Specifically, ones story was this: they went over a jump on their horse which they were training and lost memory at that point. Witnesses described them as cleaning their horse and driving home without ever noticing they broke their back.
Why does adrenaline do this? Shouldn't it make you more aware of what's going on, instead of less aware? | askscience | https://www.reddit.com/r/askscience/comments/4qzw6q/why_does_adrenaline_make_you_stop_feeling_injuries/ | {
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" > Specifically, ones story was this: they went over a jump on their horse which they were training and lost memory at that point. Witnesses described them as cleaning their horse and driving home without ever noticing they broke their back.\n\nThat seems a little exaggerated to me. If they were in so much shock they have no memory of the event, I'm pretty sure they weren't calmly cleaning their horse and then driving home - hours later.\n\nDid anyone ask for more specific detail?"
]
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4fqn9n | what happens to the occipital lobes of a person who was born blind? | Since the occipital lobes are almost exclusively used for processing vision, what roles do they play in a person who has been blind all their life? Do they shift their abilities? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4fqn9n/eli5what_happens_to_the_occipital_lobes_of_a/ | {
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"Yuppers.\nThey can become language centers instead. And something poetically beautiful- they are active when reading Braille in some...\n\nI'd post a link, to a neat journal article on it, but I feel like I've been yelled at before for links on ELI5\nEdit:\nFuck it, here's a link: \n_URL_0_\n"
]
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2j44fc | Why does smoking fish make it safe to eat? | I would like to know what actually occurs in the smoking process of say, smoked salmon, that makes it safe for human consumption. On a wikipedia article it says that the fish only gets up to 37 degrees C, which surely can't be high enough to kill bacteria on the fish? | askscience | http://www.reddit.com/r/askscience/comments/2j44fc/why_does_smoking_fish_make_it_safe_to_eat/ | {
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"(PhD Bacteriology)\n\n\"Smoking preserves fish by drying, by deposition of creosote ingredients, and, when the fish are near the source of heat, by heat penetration\" ref: _URL_0_\n\nIn fact, smoking is not a very good way of preservation. There are lots of bacteria and fungi that don't care about the smoke at all, and will grow in spite of it."
]
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"http://en.wikipedia.org/wiki/Fish_preservation"
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300eih | when and why did all cereal makers stop giving away toys in their boxes? | Growing up in the UK, this was a standard in almost any cereal box, Kelloggs, Nestle or otherwise. Where have they all gone? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/300eih/eli5_when_and_why_did_all_cereal_makers_stop/ | {
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"In 2007, new laws were introduced about how companies could advertise which products to children.\n\nIt meant that you could no longer, for example, try to persuade a kid to eat your unhealthy food.\n\nI suspect putting toys in cereal would fall foul of that, and that's why cereal adverts are now aimed at parents, telling them their kids will be well-behaved, high achievers if they eat Coco Pops.",
"Long story short, some kid somewhere ingested/choked on a toy, or other inedible prize in the box. Here's what I found:\n\n > In 1988, a Pennsylvania girl nearly choked to death on a “Cool Flutes” in-box toy from Kellogg’s Rice Krispies and Cocoa Krispies cereals, according to the U.S. Consumer Product Safety Commission.\n\n[Source](_URL_0_)\n\nThere was also a one year old that died (who lets their one year old get their own cereal?), and while these incidents didn't \"directly\" cause all cereal companies to stop putting toys in the boxes, I'm sure they'd rather be safe than sorry.",
"Probably after more and more people sued them because their children supposedly choked up putting those toys in their mouths (which I bet 99% of the cases were false)",
"Cereal manufacturers are still giving away toys in cereal boxes in the United States. Source: I have a six-year-old son.",
"They haven't stopped entirely. As of the last time I bought it, General Mills had cereal with Mega Bloks cars sponsored by Hello Kitty and Power Rangers. [linky](_URL_0_)\nI'm not convinced that the reduction in practice has anything to do laws or lawsuits. This just seems like a simple decision to save money. If their market research said it was more profitable to sell without toys, then so be it. In the case of Mega Bloks with Hello Kitty and Power Rangers, the external companies likely just paid enough to make it worthwhile.",
"It has to do with the costs and theoretical danger. Kellogg received a lot of backlash in 2004 when they had to recall a ton of boxes because a [Spiderman watch](_URL_2_) used a [mercury battery](_URL_1_).\n\nIn 2008 Kellogg did have a [Batman toy](_URL_0_) in their cereal but for the most part these days since things are going digital a lot of companies just do 'codes' and 'coupons' for their incentives just to be safe. \n\nIf they do include a toy it's going to be a hunk of plastic that doesn't have joints or whatnot to come apart easily. Look at companies like Kinder who have drastically changed their toys in the Kinder Egg. I remember as a kid having to built something out of 10 pieces but now it's a one piece or 2 piece toy.\n\n~~Kids are dumb.~~\n\n**Edit:** Okay bad parents are dumb",
"Well I just got a pack of \"skystone\" cards in my (U.S.) cheerios the other day, so they're not all gone. ",
"I just got an Avengers flying disc last week. It's rare, but it's still around.",
"My understanding, at least in the US, is that embedding inedible objects among food is now unlawful. Perhaps this is why?",
"most cereal brands still give out toys here in portugal, except they come, and always came in plastic bags inside the box, outside the plastic containing the bulk of the cereals",
"Because lazy moms let their kids eat the toy because they're stupid",
"I just got a Nemo spoon in a box of fruit loops my damn children stole it...",
"Because people would rather sue when their fuck trophy swallows a toy than actually raise their kid to not be a window licker.",
"From what I remember a few years ago, the major brands agreed to [voluntary guidelines/standards] (_URL_0_) in regards to nutrition content and advertising to kids. It was obviously their attempt to keep the government from proposing their own, harsher standards. ",
"Canadian here. Not sure if Ontario laws are the same but lately we've been seeing a temporary revival in cereals I used to have as a kid. Like Trix! Also...I have an old Nestle Quick red spoon from the late 90's. So they've been doing the spoon thing for some time now. \n\nAlso, doesn't America have laws against handing out food with toys? Aren't Kinder Eggs band there? Cereal boxes could count as the same as a Kinder Egg, no?",
"Because lawyers got involved and sucked the fun out of everything. ",
"Someone finally ran it by legal...\n\nMarketing: can we put a small but large enough item that if swallowed by a child could cause him to choke and die?\n\nLegal: (while throwing pen in air) COME ON!!!!\n\nMarketing: (looks on dumbfounded)\n\nLegal: (FACEPALM)\n\nMarketing: Well, we can tell the higher ups we ran it past legal....",
"I miss cereal box prizes. We didn't have a lot of money as kids, we usually got the malt-o-meal bagged stuff. Once in awhile though, we'd get \"good\" cereal and get a prize. When I was an adult, and started buying my own cereal, I looked for a box with a cool toy but they don't have them anymore. \n\nIt's one of those things I really looked forward to seeing my kids do. Those bastards, ruining it for everyone. Same with cracker jack toys. They're shitty stickers now. I'm from KC, I opened a box of cracker jacks the morning after the last World Series game. It was a fucking San Franciso Giants sticker. ",
"Last year Kellogs Coco Pops gave away hacky sack toys in each box, I know because I have several around my house including the golden one\n\nEdit: It was to celebrate The World Cup in Rio I believe",
"When they figured out that they could simply add more sugar.",
"Why can cereal manufacturers put toys in your food for the longest time but Kinder eggs are still banned!",
"When you can hook kids with online \"prizes\" for next to nothing. ",
"Is this why the prizes in Cracker Jacks are so shitty now? IE, just a sticker or trivia wax paper?",
"On a side note, how come beer companies don't seem to include hats and stuff in cases anymore?",
"Because they're expensive to produce and must not have created enough of a return on the investment. People buy cereal without that incentive.",
"I miss the mini lightsabers they put in the boxes.",
"There were some Skylanders cards in a box of Trix I recently opened.",
"Why don't toy makers start including cereal in there packets?\n\nI´m a glass half full guy. ",
"Chinese plastic=toxic.\n\nPlus choking hazards or some such thing.",
"Probably for the same reason that many of the cereal mascots have gone away, stricter advertising rules for targeting children.",
"Cost. Cracker Jack still has something, but they are just paper junk, nothing good anymore. ",
"Because parents only care about price when buying cheap cereal, and cereal manufacturers found it was better for the shareholders if they reduced the price by $0.10 and left out the $0.15 toy.",
"How do McDonald's get away with it in happy meals",
"because the toy's we got growing up in cereal boxes would not impress the iPhone generation of today. ",
"What do you mean? I got something from my Honey Nut Cheerios box, just this morning. Something for Skylanders.",
"I'm pretty sure that in Europe, adding toys to cereals got outlawed.\n\nI bought some cereal recently a couple of years ago that had a description on it saying that by EU law they can't have toys inside anymore, so there was a sticker on the outside instead. It used to have small wodden toys in it (no choking hazard or shit like that unless you're 100% dumb as a brick).\n\nEdit: This made me curious so I e-mailed my cereal company of trust, I'll update the post if they reply!\n\n**Edit2**: They answered my mail, so as promised, the reason:\n\nIn the EU, some law went in effect on 20th July 2011, which is the **§48 EG** which outlaws hiding toys **in** the food itself. Therefore, they cannot put toys into the bag anymore for legal reasons!\n\nIf you want to search for it, it's named the\n\n**Toy Safety Directive 2009/48/EG**",
"Kids don't play with toys as much anymore, just iPads. They can't include those in boxes, so why bother.",
"Chocolate frosted sugar bombs still has the mail in for a propeller beanie.......",
"They have other promotional items now. I remember getting CDs with computer games around 5-8 years ago, and more recently, movie tickets.",
"Digital goods are cheaper to manufacture and pack in.",
"They haven't in the US. It is still very common to get toys in the boxes. ",
"while we're at it can someone chart the reduction of quality of Cracker Jack toys and see if this coincides with the Cereal box toy eliminations? ",
"This message might get flooded out but basically it is illegal in the US to sell a food product with anything non-edible that is sized to be able to be swallowed, this excludes drinks if it is not in the drink itself. It is also why the chocolate eggs with toys inside are illegal in the US but legal in Canada. \nThe reason why most cereal companies don't do^@ that is because the blunt of there sales^@ are in the US. \n^@ Spell checked",
"As someone who has worked in a Kelloggs cereal manufacturing plant, it has just become too expensive to include extra items like that. The cereal industry as a whole has begun to deline.",
"Apparently US children can't differentiate food to toys, that's also why they are not allowed kinder surprise....",
"I bought a box of Reese's Puffs a few months that came with a Mega Bloks car. Still have the box as well. lol\n\nPeter Griffin: You got Legos? Aw, sweet! Lois only buys me Mega Bloks.",
"I got a car in my box of golden grahms yesterday. It came with stickers. Instructions tell you to cut out the box and it will be a ramp you can make the car jump. Through a smaller hole on the other end. Pretty cool! Edit. Mine was also a mega bloks car! ",
"In the netherlands we had a collectable inside bags of chips (flippo's). An old lady choked on one and they got prohibited.\n\nIt might be something similar about toys in the cereal boxes",
"The worst thing about toys inside cereal boxes was when the coolest toy was inside the cereal you hated the most.\n\n'Do I get the hockey cards inside the rice krispies cereal or just get sugar crisp with nothing inside?' Fucking hardest decision a 8 year old has to make.",
"They only did it for you, when you grew up they quit. "
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30rcmo | since atoms can't touch each other, what causes friction between two objects? also, how does this friction cause heat when the atoms don't actually touch? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/30rcmo/eli5_since_atoms_cant_touch_each_other_what/ | {
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"Repelling each other requires energy. Some of that is released as heat.",
"Friction is less to do with atoms and more to do with microscopic imperfections. When you observe a surface, it probably looks very flat to you, a macroscopic entity. However, on a microscopic level, the imperfect surface is more like a series of mountains and hills. Now, imagine two mountainous surfaces moving upon one another. The tips of these mountains grind across the tips of the other surface's mountains, and you arrive at what is macroscopically known as kinetic friction (static friction also exists while the surfaces are motionless).\n\nNofftastic is simplifying the concept. After all, when two motionless objects are in contact, there is no heat coming from the friction even though there is clearly a repulsive action occurring. In fact, repulsion of like charges is an intrinsic property of charged matter, and does not require energy to exist. It does require energy to move like charges closer, however.\n\nIn introductory quantum mechanics, there exists the notion of a minimum separation distance between two particles in a single system (a geometrical consequence, see Griffiths QM). This constraint generalizes to systems of many particles. While repulsion is nonnegligible, this quantum mechanical separation distance is largely responsible you not being able to walk through walls.\n\nThe heat is a result of KINETIC energy being converted to THERMAL energy. If we revisit the mountain picture, imagine the peaks breaking off as they move across on another. In other words, the surface is being otherwise compelled to move more than before. Since the average speed (v) of the molecules composing the surfaces increases as a result of the microscopic interactions mentioned above, the kinetic energy (0.5mv^2, notice the dependence on the speed v) increases as the objects slide across each other at higher speeds. This is converted to thermal energy, and arises observably as an increase in temperature."
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3d61rb | Is this predicted Mini-Ice age, bunk? Does it have any impact on the consensus around Climate Change. | A friend posted a link to an article on AOL that described a "mini-ice age". The article was short on refernces (none that is) but was similar to [this one](_URL_0_). To my unscientfic mind it seems to describe an effect of the Sun's solar cycle and has nothing to do with Climate Change. I just don't know how to validate and justify this view. Please help if you can.
Thanks | askscience | http://www.reddit.com/r/askscience/comments/3d61rb/is_this_predicted_miniice_age_bunk_does_it_have/ | {
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"I'm not sure if \"bunk\" is the right word, but the media have sure done their best to make a huge story out of a very minor scientific result. [Here is the original press release on the subject](_URL_0_). What happened is a group at a university in England developed an idealized model of the sun that has good agreement with past observations of solar activity, using a unique approach that has never been tried before. When projecting this model into the future, it suggests that there will be a continued decrease in solar activity, reaching a minimum from 2030-2040. It is an interesting result, but it is very preliminary. Many questions still need to be answered:\n\n* Will the results hold up to peer review? (these findings are not even published yet, so we can't yet analyze their data and results)\n* Does the model agree with data beyond the initial 30-year analysis time period?\n* How robust is the model? Is it finely tuned to reproduce the available data, or does it naturally mimic observations?\n\nNote that I haven't even talked about climate yet. That's because literally no science has been done on the climate side, that has all come from journalists (probably too generous of a word in this case; the first I saw of this was from the Daily Mail of all places). Even if the model's predictions stand up to initial scrutiny, there are tons of questions that need to be answered before we know what effect this could have on climate. It could cause a slowdown in warming global temperatures ([this paper](_URL_1_) actually looked at such a hypothetical case in the past, showing very little change in global warming trends) but it's pretty much pure speculation at this point.\n\ntl;dr: **Conference presentation on very new, hypothetical model that suggests solar activity minimum for the next few solar cycles --- > \"News\" media --- > THE WORLD IS GOING TO FREEZE OVER IN 15 YEARS**\n\ntl;drtldr: Don't trust news reporting on science."
]
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"http://www.telegraph.co.uk/news/science/11733369/Earth-heading-for-mini-ice-age-within-15-years.html"
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72adaf | What would a circle look like if the ratio of its circumference to diameter was 3 instead of pi? | In Arthur C Clarke's series A Time Odyssey, there are spheres that have the ratio as 3 instead of pi and I was wondering what they might look like. | askscience | https://www.reddit.com/r/askscience/comments/72adaf/what_would_a_circle_look_like_if_the_ratio_of_its/ | {
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"A circle is the set of points that are equidistant from a central point. There are a couple ways to cheat at this to get different ratios from this distance and the arclength of the object. First, by making space look different. Second, by changing what \"distance\" is.\n\nYou already have some experience in the first. Pick a point on the Earth and draw all the points that are the same distance along the Earth from this point. Since distance is measured along the Earth, rather than some flat distance to these points, the ratio between the circumference and the diameter will be different. If you pick the North Pole as your point, and draw the furthest circle from it, the equator (you can argue that a circle on the other side of the planet has the South Pole as its center), then the ratio between circumference and diameter is 1/2. So, somewhere between a circle around the equator and a circle right next to the North Pole, there is a circle whose \"pi\" is 3. This circle doesn't really look any different from any other circle, just how you get to the center has changed since we've changed the object that we're drawing circles on, and it doesn't matter that the \"pi\" is rational or an integer or whatever.\n\nThe other way is to redefine distance on a flat plane. For any number p > =1, you can define the distance between the point (a,b) and (A,B) as (|a-A|^(p)+|b-B|^(p))^(1/p). Unless p=2, this notion of distance isn't as nice as the one we're used to, but it still defines a notion of distance. This is the [Lp-Norm](_URL_1_), and the set of points that are equidistant from a fixed point are different (as illustrated in the link). So, you can get an Lp-pi by measuring these ratios. In this case, though, the ratios increase as you change p. So p=2, which is the familiar case, has the smallest Lp-pi of 3.14159..., so you can't get 3 using this method. But you can get many others [see here](_URL_0_), and, again, you can hit rational and integer values and it doesn't really mean anything.",
"As people have stated to have a sphere at all you need to have all points equidistant from the centre. Pi is a constant that relates radius^n to circumference, surface area and volume (with an extra factor of 2, 4 and 4/3). If you decide to fix one of these you can change the metric of distance. If you use the a metric of absolute value |x-a| + |y-b| you actually have a square / cube which is a sphere with Pi = 4. \n\nThe problem is that what the author said is very ambiguous, you can get away with that in literature but less so in physics! There is also a sphere with pi=3 in going postal in the disc world series actually."
]
} | [] | [] | [
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"https://math.stackexchange.com/questions/2044223/measuring-pi-with-alternate-distance-metrics-p-norm",
"https://en.wikipedia.org/wiki/Lp_space#The_p-norm_in_finite_dimensions"
],
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] | |
2mipyh | When did the practice of the repatriation of war dead begin? | I was taught at school that in WW1, UK and Commonwealth forces established cemeteries in France and Belgium because there were too many bodies to be able to repatriate them all in a timely fashion. Is there any truth to this or is the process of repatriating war dead a recent phenomenon? What happened to soldiers killed in, say, the Crimean War?
In the same vein, when did it become common practice to inform next of kin? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2mipyh/when_did_the_practice_of_the_repatriation_of_war/ | {
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"Hi! [I wrote this massive long (and slightly incoherent) post on the moral problems with *not* repatriating the War dead from World Wars One and Two.](_URL_0_)\n\nThe \"soldier's five\" explanation of that post is this: that after World War One, the bodies of the war dead were effectively \"stolen\" for political purposes by the head of the Imperial War Graves commission (a man named Fabian Ware).\n\nSo let's also set out some more terms; the British Army at the start of both wars was an industrial, western-style force with a modern logistics train. This was similar the other major powers of continental Europe say, France. Britain was also a protestant country, and not Catholic. The difference this later part makes might not be immediately apparent, but we'll get to that. \n\nSo going back to the first post, the way I use the word \"stolen\" might give the impression that keeping the bodies of the war dead from their relatives was not normal - and this is half correct. Before the First World War, \"ownership\" of the British body in a moral sense rested with the families, and those families were free to reclaim the body at any time - if they paid for it. Bodies rapidly decomposed - there were no refrigerated or mobile morgue units like there are today. Most commonly, the body was buried on-site and a note was made of its location. At some later date, the family would retrieve the remains and return them to the burial-place of choice. This was a costly enterprise.\n\nFor \"lower ranks\" this might seem a raw deal, and it is. However the British Army made institutional use of the soldiers' families before the large-scale industrial armies of the late 19th and 20th centuries. Prior to that point, it was not uncommon for wives and children to accompany their fathers and husbands on campaign; these \"camp followers\" completed tasks such as laundry, cooking, and other tasks which today are performed by specialized military units. In the context of death, the soldiers were killed and could be mourned by their family near where they fell without the need for costly transportation - the social network was also equipped and ready to deal with grief within their ranks. See the New Zealand Wars for examples of this practice. \n\nFor British sailors, bodies were not returned. Instead they were buried at sea, and a message would be rent from the Admiralty to the next-of-kin listed on their papers. (The Admiralty was the progenitor of all modern bureaucracies - the first modern office block, for instance was built for the British Navy). The bodies were not kept for pragmatic reasons - dead bodies on a slow and crowded wooden sailing ship is a recipe for sickness and filth (although Nelson was considered an exception, and was pickled in a barrel of brandy for transport back to British soil. Further, during periods such as the Napoleonic Wars, the British were blockading the French Coast - they were \"on station\" for months or even years, unable to go back to British soil. keeping bodies under those circumstances would have been untenable. We can actually see how poorly thought out bringing the bodies home would have been by contrasting the British practice historically with the French. Remember how I mentioned the French were Catholic? They *did* bring their sailors killed back to shore - if the sea hadn't made that decision for them - because they believed in the literal Resurrection of the body. During the Napoleonic Wars, the bodies were packed in the ballast sand at the bottom of the ships for transportation. I am unsure if this practice was implemented only by some captains or if it was policy, but it was widespread enough to be commented on by the RN. Making this practice slightly less disgusting, the French tended to stay close to their own shores and would have been able to off-load their grisly cargo much more swiftly than the British during the same period.\n\nThe advent of refrigeration, the distance between the families and the battlefield, and the introduction of conscription radically changed the understandings for how the war dead would be treated. Introducing conscription meant new social networks had to deal with their service-person being killed prematurely - mostly the middle class - and in a way that previous rituals and symbols could not cope with. But transportation costs and technology - for British people at least - should have made it practicable to return the bodies to the Home Isles.\n\nYour school is therefore white-washing a phenomenon which was particularly painful for people trapped inside its web; for all classes, they were not socially equipped to deal with the bodies not being returned; for the least wealthy members of society, they were not near-enough to the conflict to mourn \"on site\"; and for the middle-class and the wealthy, they were forcibly prevented from returning the bodies themselves. This placed enormous strain on the social fabric of Britain, and its effects can be still felt today.\n\nThis was a massive question and I had to go over it tremendously quickly. I hope it was helpful though."
]
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"https://www.reddit.com/r/AskHistorians/comments/1iuwrx/were_many_people_upset_when_they_announced_they/cb8bich"
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7jkd0r | Can someone explain to me this map from the 9th century Europe? | [This map](_URL_0_)
I can't find any useful information on it, but the interesting things about it are that 1. Albania is located near the Caspian sea (east of Iberia and Armenia) and 2. Serbia (Servia) is much larger than it is normally thought in that period, and if we take into account the fact that there was no people named Bosniaks, Montenegrians or Macedonians, does that mean that this is some precursor to the later Serbian kingdoms, empires etc.? Btw, this isn't a "homework" question, just interested in possible explanations.
EDIT: was going to say, especially since the first mention of the word "Serb" was in 822., officially. | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/7jkd0r/can_someone_explain_to_me_this_map_from_the_9th/ | {
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"The boring answer is that its not an accurate map, or intended to be one since its from an atlas for schoolchildren from 1905. From the [preface](_URL_0_):\n\n > The principles which have been followed are mainly two-never sacrifice clearness for the sake of detail, and to let each map deal with one period only; in short, we have aimed at telling one story at a time and at telling it graphically in clear and easily-remembered outlines.\n\nYou can see how this map would be to illustrate the \"story\" of the domain of Charles alone, with vague or incorrect detail everywhere else.",
"As for Albania being in the Caucasus, I believe the map says \"Alania\" and is probably referring to the Alans, speakers of an Eastern Iranian language who did indeed live in the Caucasus in the Early Middle Ages. Some Alans were among the various ethnic groups invading the late Roman Empire, but not all participated in this migration. The modern-day Ossetians are thought to be the descendents of the Alans and still exist as an ethnic minority, mainly in Russia and Georgia (There was a war about it you may remember, back in 2008)"
]
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"http://www.emersonkent.com/images/maps/europe_814.jpg"
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"https://www.lib.utexas.edu/maps/historical/history_colbeck_1905.html"
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ahhjxw | why do front wheel cars handle better on ice and snow than rear wheel? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ahhjxw/eli5_why_do_front_wheel_cars_handle_better_on_ice/ | {
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"They only accelerate better because the weight of the engine on the drive wheels. They don't stop or turn any better than rwd.",
"When turning and accelerating one component of the acceleration is sideways which helps pull the car through the turn. Also there's usually more weight over the front wheels so they dig in a bit better.\n\nWhen the wheels do cut loose, front wheel drive is much less prone to fishtailing and spinning. If the driver hits the gas too hard so the drive wheels cut loose, a front wheel drive will \"understeer\" or stop turning while a rear wheel drive will \"oversteer\" or fishtail.",
"There are 2 main reasons.\n\nFirst, most cars have more weight over the front axle than the rear. FWD cars usually have ~60% of the weight over the front, while RWD cars usually have only ~40-50% of the weight over the rear wheels. \n\nSecond, if your drive tires start spinning, it's relatively easy to handle in a FWD car. You just let off the gas a bit, and maybe turn in more. In a RWD car, you need to ease off the throttle, but not too much, and turn in the opposite direction. It takes more skill. That said, modern cars with stability control can pretty much negate this issue.",
"Put a pen flat on a table.\n\nFirst, drag it along by its tip. Then, push it in the game direction from the back.\n\nWhich of the above resulted in a more stable path? Obviously the first.\n\nSame thing with a car. With FWD, the front wheels are dragging the rest of the vehicle behind it, resulting in a more stable trajectory. With RWD, the rear wheels are pushing the rest of the vehicle in front of it, which isn't stable in limited traction scenarios."
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5ep20a | what is the process to get a case up to the supreme court of the united states? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ep20a/eli5what_is_the_process_to_get_a_case_up_to_the/ | {
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"You file a case in trial court. If it's a question of federal law, you can file it directly in federal trial court (called the District Court). You can also file federally if the parties are diverse (that is, they're from different states) and you meet a certain dollar amount in controversy (it was $75,000 when I was in law school, not sure if they've changed it again). Otherwise you have to file in the state court system of your state. (But if can still get to the Supreme Court if there's a federal issue involved.) \n\nThe other way cases are initiated that often involve federal questions is if you get arrested and the state initiates a criminal prosecution against you.\n\nAfter trial (either in state or federal district court), the losing party cas file an appeal. Most (all?) court systems in the U.S. have at least one appeal as of right, which means you are guaranteed an opportunity to make your case to the appellate court. N.B. that if the defendant in a criminal trial is found not guilty, the state cannot appeal.\n\nThe federal appeals court is called the Circuit Court. There are 13. States have similar mid-level appeals courts.\n\nAfter you lose at the Circuit Court you can file a writ of certiorari to the US Supreme Court. There's no guarantee they will hear your case. They pick cases based on whether they think there's a question of law that needs an answer, not in order to do justice in individual cases.\n\nIf you're in state court, the state will have a similar process to get to the state Supreme Court, although there might be more or fewer levels in some states. If you lose in your state Supreme Court, if you think the state system got a rule of federal law wrong, you can file a writ of cert. to the US Supreme Court from there too. But if it's a matter of state law (like, what exactly counts as that state's version of second-degree murder, or the proper width of sidewalks, or whatever), the US supCt has neither inclination nor authority to consider it.\n\nThere are some exceptions, but this is the basic way it works.",
"You go to trial in a city or country court. You lose.\n\nYou appeal to the state appellate court. You lose.\n\nYou appeal to the state supreme court. You lose.\n\nYou appeal to the federal circuit court. You lose.\n\nYou appeal to SCOTUS. They decide to take your case.\n\nNote there are a lot of variations to this. You can win, and your opponent can appeal. If the grounds for appeal is a matter of federal law, or a interstate dispute, you might go straight to the district court. But in general, every case starts at the local level, and moves through the state, then federal level before it winds up in the Supreme Court. "
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[],
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1z2dht | what would happen if you ate laxatives but didn't have anything left to let out? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1z2dht/eli5what_would_happen_if_you_ate_laxatives_but/ | {
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"Lots of cramping and dehydration. ",
"Once when I had to go under colonoscopy I took laxatives for a period of time, up until it would still make me want to go, but nothing would come out. Didn't hurt or anything, it's just like normal pooping, but much cleaner :P"
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h7w7l | Question: Why are mosquitoes not a leading cause for spreading the AIDS virus? (Because i genuinely don't know.) | So if you share needles with an AIDS patient you are susceptible to contracting the virus.Considering a mosquito sucks blood from quite a few people in his _URL_0_ it possible to contract the virus after it has bitten an AIDS patient.I assume not, but why is it so?. (Ignorance ....help!) | askscience | http://www.reddit.com/r/askscience/comments/h7w7l/question_why_are_mosquitoes_not_a_leading_cause/ | {
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"I don't think there is enough blood tranmitted when you are bitten by a mosquito.\n\nThe transmission of malaria via mosquitos occurs because the organism that causes the disease (a Plasmodium, usually Plasmodium falciparum) end up in the moquito's salivary glands. The mosquito's *saliva* ends up in your blood stream, not the blood of the previous meal. \nThe Plasmodium's journey from the blood meal in a mosquito gut to the salivary glands is complex. The malaria-causing Plasmodia have evolved to survive through this multi-organism, multi-organ lifecycle. HIV, to the best of my knowledge, is unlikely to have the genetic resources to complete this task.\n\n and something that the Plasmodia are very good at. HIV are not nearly as complicated (genetically) and are unlikely to be able to acomplish this ",
"gonna leave [this](_URL_0_) here. "
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1cl0zk | Can a mosquitos proboscis pop a water balloon? | I should go to sleep | askscience | http://www.reddit.com/r/askscience/comments/1cl0zk/can_a_mosquitos_proboscis_pop_a_water_balloon/ | {
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"Not a standard water balloon. We have to use special parafilm bags for blood feeding. There is usually a thin \"window\" that allows the mosquitoes to feed naturally and easily. If the membrane is too thick (i.e. like a water balloon), the mosquitoes will not be able to feed. Because of the bag material and lack of extreme internal pressure, our blood feeding bags do not explode when mosquitoes puncture them."
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3smfo2 | after brain damage, what would the requirements be for full regeneration without scar tissue? | I read that these are the requirements but I would like an explanation of these please so i can understand it better. How can liver cells repair even when a lobe of it is missing? is it the same process as what we would need in the brain?
Brain regeneration can be divided into five steps: (1) anterior blastema formation, (2) brain rudiment formation, (3) pattern formation, (4) neural network formation, and (5) functional recovery.
Is this true? Is there anything missing?
why can't we just inject stem cells into the brain and watch them grow the rest of the brain?
| explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3smfo2/eli5_after_brain_damage_what_would_the/ | {
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"I'm not an expert on neuron regeneration, but I can tell you that the liver contains stem cell which mitotically active (able to divide) which is why the liver can regenerate. Neurons are not mitotically active, and do not contain stem cells, so if the cell body is destroyed, they cannot regenerate. Axons, however, can regenerate, but this does not involve cell division, just cell growth. "
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2ie65g | Was Mahatma Gandhi really racist against Blacks and Muslims? IF this really is true, did he change his views later on in his life? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2ie65g/was_mahatma_gandhi_really_racist_against_blacks/ | {
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"I was surprised to find this exact question hasn't been asked before, but there is a lovely comment by /u/Bernardito/ over [here](_URL_0_) which covers your second question, and as a result, your first as well.",
"A good source on Gandhi's own views regarding this question is “Hind Swaraj”, originally published in Gujarati in 1909, proscribed by the colonial government and consequently published in an English translation in 1910. Here he eleborates his concept of *Satyagraha* (passive resistance), influenced by his experience of and subsequent resistance to South African racism and segregation. As mentioned before, this can be seen as a marked change of Gandhi's earlier views, which were influenced by his studies in England and endorsed British colonialism.\n\nIn “Hind Swaraj”, on the question of whether the introduction of Islam in India (in the Middle Ages) has unmade the nation: “*If the Hindus believe that India should be peopled only by Hindus, they are living in dreamland. The Hindus, the Mahomedans, the Parsis and the Christians who have made India their country are fellow countrymen, and they will have to live in unity, if only for their own interest. In no part of the world are one nationality and one religion synonymous terms; nor has it ever been so in India.*“ (p. 270) \nConcerning a supposed 'inborn enmity' between Muslims and Hindus: „*The Hindus flourished under Moslem sovereigns and Moslems under the Hindu. Each party recognized that mutual fighting was suicidal, and that neither party would abandon its religion by force of arms. Both parties, therefore, decided to live in peace. With the English advent quarrels re-commenced*.“ (p. 270) A common ancestry between many Muslims and Hindus is also emphasized. \nThe English tactic of “divide and rule” is often described by later authors as pitting Indian Muslims against Hindus by taking one party's side, and thus accentuating the differences and conflicts between the religious groups.\n\nAt the time of Independence Gandhi also strongly opposed the 'two-state' scenario leading to the division into India and Pakistan, he had worked towards cooperation between Congress and the Muslim League. He visited areas in danger of rioting such as Bengal and Bihar in 1947 (and even during the proclamation of Independence on August 15th) in order to prevent further bloodshed.\n\nSource: Gandhi, Mohandas K., Hind Swaraj or Indian Home Rule (Revised New Edition), Ahmedabad 1939. (online: _URL_0_)\n\nEdit: Source\n"
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bsg4ri | How did we discover molecular processes like the Krebs cycle or electron transport chain? | “I need someone to explain this to me like I’m a 5 year old” - Michael Scott
It’s very easy to see how astronomers can look at large moving bodies and formulate a hypothesis and test the hypothesis with models and then identify if celestial motion can be accurately predicted. How do we do this in a cell? How do we replicate cellular biology? It’s blowing my mind and I assume these processes work so fast and are so small that we can’t visually see them. | askscience | https://www.reddit.com/r/askscience/comments/bsg4ri/how_did_we_discover_molecular_processes_like_the/ | {
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"How we do it now vs how it was done at the discovery are very different.\n\nToday we have both the tools and the understanding that we can actually measure some aspects of biology in real time. Ultra fast cameras, high powered lasers, high speed processors, have all contributed to our ability to ramp up our observation capacity to match that of what's actually happening in our cells.\n\nBefore technology helped us catch up what we (and by \"we\" I mean the absolute legends who's names fill our text books) did was actually measure bulk flow of reactions, and determine what must have happened microscopically in order for the macroscopic change to occur.\n\nPerhaps you've seen chemistry experiments that mix two clear solutions and results in a color change? Its similar to that. The individual reactions at a molecular level are much to fast to have been observed independently, however en mass they are observable.\n\nMany of the founders of biology were pure chemists who understood how to chemically isolate and identify compounds. So they could take tissues and dry them out, then separate the powder to figure out what they were made of. For tissues that happen to be very densely packed with mitochondria like the liver and skeletal muscle, the molecules of the Krebs' cycle made up a large component.\n\nThere are so many really amazing techniques used and pioneered by this generation of scientist that truly laid the foundation of modern biochemistry.\n\nHere's a brief account of Krebs' work\n\n[_URL_0_](_URL_0_)\n\nHere is a more detailed account of the state of science during the life of Hans Krebs'\n\n[_URL_1_](_URL_1_)",
"I'll answer your question as well as trying to explain concepts as simple as possible in two parts: part one is the discovery of the Krebs cycle, and part two is how we can confirm/replicate molecular processes.\n\nIn the 1930s, scientists knew a good amount about fermentation, which does not use oxygen, but didn't know much about aerobic respiration. It wasn't fully understood how oxygen and carbohydrates came together to produce energy. Hungarian scientist Albert Szent-Györgyi did some of the initial research into this and is credited with discovering some compounds involved in the Krebs/TCA cycle. He did this by testing different compounds and their effects on cellular respiration on pigeon breast tissue. He noticed that when a particular group of compounds called dicarboxylic acids was applied to the tissue, way more oxygen was being used by than tissue than what should be needed to oxidize the compounds [[1]](_URL_0_). \n\nMost of biochemistry involves the transfer of electrons in what are called redox reactions; in the case of these dicarboxylic acids, they are able to donate hydrogen atoms (oxidation) to facilitate the production of energy (reducing other compounds). Szent-Györgyi saw that this was occurring in the tissue in excess, and realized that these acids were not being used as energy, but were catalyzing reactions (start and end the same in a chemical reaction) that utilized other compounds for energy. He came up with a working hypothesis for some compounds at work, and validated his results. \n\nHans Adolf Krebs would also validate the work of Szent-Györgyi, but would go further and put all the compounds together into what we now know as the Krebs cycle [[2]](_URL_1_). We also call it the tricarboxylic (TCA) cycle, which I think is nice because Szent-Györgyi helped lay the groundwork for Krebs to build on. Szent-Györgyi got caught up on his dicarboxylic acids, while Krebs realized that citric acid, which is a tricarboxylic acid is the key compound in the TCA/Krebs/citric acid cycle.\n\nI think the best way to answer how we replicate cellular biology is using models/assays in a careful, controlled, and methodic manner. You can't just throw all these Krebs cycle compounds into a test tube and expect it to work. Szent-Györgyi and Krebs carefully came up with a hypothesis for what's happening in respiration, a system to test this, carefully tested each portion of their model, and then put all their results together into scientific papers.\n\nSource: in text and I'm a PhD student in molecular biology.",
"It's always a gradual process. You start with a simple \"it just happens\" explanation, that you then refine as you discover more details about the phenomenon.\n\nSo in physics, for example, the atom was just a solid ball for Dalton because that was enough to explain the behavior of an ideal gas. Later, when cathode rays were observed, Thomson added electrons into the mix, but also had to invent a positive \"liquid\" to explain why atoms were electrically neutral. But no nucleus or orbits because the model didn't need them to explain the known body of observations. And so on and so forth until the modern understanding.\n\nBTW all sciences nowadays are very complex. Astronomy, for example, isn't just looking at the sky, there's a lot of complexity in the analysis of the data before they can conclude the composition of the atmosphere of an exoplanet or other things like that.",
"A lot of this research was boosted by the availability of isotopically labeled compounds. Compounds could be labeled with ‘heavy’ versions of an atom, which could then be tracked through various metabolic changes by looking for downstream compounds containing the label. To cite one example, the pentose phosphate pathway was determined through carbon-13 labeling. Alternatively, those same compounds could be labeled with radioactive isotopes, which made it even easier to track them through chromatography.",
"Usually through pharmacology. Certain drugs are known to block certain processes. Through combinations and observing the dynamics of different agents in different conditions, we can drill down a pretty good idea of how a molecular process probably works. All is subject to change as we learn more about the system.",
"I liked the answer that references the enormous advancements using isotopes in modern biology has provided. And today, using mutations and genome wide genetic screens are standard. These techniques allow scientists to see disruption of a pathway and workout the details of a pathway. \n\nThough, Kreb's generation, in my opinion, had it much tougher. He measured oxygen consumption after stimulating tissue slices with amino acids. Once a compound, like acetyl-CoA, was found to be oxidized in the presence of oxygen and tissue slices, he had a reaction that lends itself to identification of a pathway.\n\nIt was really abstract and required a genius to make inferences from the results, which eventually allowed the mechanisms to be worked out using tissue homogenates from which organelles were isolated using centrifugation. After testing all of the fractions on his reaction, he found that isolated mitochondria were responsible for the strong oxidations.\n\nSubsequent steps involved fractionating the mitochondria into components that could catalyze the same reactions, or atleast start the reaction. Combining the fractions of enzymes could eventually complete the entire reactions observed in the tissue slices. \n\nSo, it was really what was called a 'reductionist approach' to discovery. Scientist that follow this path believe that every reaction can be 'reduced' into finite reaction and reconstituted into a biologically relevant pathway. \n\nDuring the process of discovery, it was found that Kreb's reaction would produce more oxidation than predicted by the single consumption of a limiting amount of acetyl-CoA. The only explanation was that the resources were being regenerated and were thus the process was cyclic in nature.",
"People eat plants. Plants we eat have been important to humans for a long time. We’ve tried really hard to figure them out. The better we figure out plants, the better we can eat. Humans like eating. Can you name some plants you like eating?\n\nPeople who grow plants on farms are called farmers. Some years, farmers can grow a lot. Some years, farmers can only grow a little. Farmers want to grow a lot. Farmers pay attention to things they think can help them grow a lot of food. \n\nThings farmers have noticed help grow food include the right amount of water and sun, as well as nutrient-rich soil. Without water or sun, plants just don’t grow. With too much water or sun, planets can’t survive. Farmers want to get the “just right” amount of water and sun and soil. \n\nBut there was something farmers couldn’t figure out: where does the stuff that plant are made of come from?\n\nDo plants come from things they take out of the soil? A sciencey guy from three hundred years ago, Jan van Helmont, tried to figure this out. He weighed a pot of soil before he planted a plant in it. Later, he took the plant out and weighed the soil again. The soil didn’t loose much weight. He guessed that most of the weight of the plant must be from the water he added. \n\nAround the same time, other sciencey people were looking into other things related to the discovery of photosynthesis. \n\nJoseph Priestley put individual candles in upside-down jars. Some he lit and some he left unlit. The ones that lit went out quickly. Some of the ones he lit, he also put a plant inside the jar. If you’re reading this, it was copied from the internet. Later, he lit candles without the plants couldn’t be lit. The unlit candles could be lit. The lit candles with plants could be lit. This means that the plants somehow restored the part of the air that lit the candles. \n\nNot to long later, Jan Ingenhousz did a very similar experiment. He found out that the air is restored faster in sunlight. \n\nAbout 15 years after that, Jean Senebier showed that what plants in these experiments were using carbon dioxide and releasing oxygen in about the same amounts. This was still many hundreds of years ago, though, so he used different words for the chemicals. \n\nSoon afterward, Nicolas-Théodore de Saussure showed that the mass a plant gains is the amount of carbon dioxide and the amount of water put together. \n\nBy now (many upside-down jars later) they figured out that carbon dioxide and water result in oxygen and plant material (glucose). \n\nLater, sciencey people figured out more specifics. Some of photosynthesis happens only in the light. Some of photosynthesis can happen in the dark. By changing the experiment, little by little, they were able to learn new details. Now, experiments use different plants (or even algae), fancier containers than jars, and instruments that measure much more than it weight."
]
} | [] | [] | [
[
"https://academic.oup.com/labmed/article/41/6/377/2657667",
"http://www.jbc.org/content/277/37/33531.full"
],
[
"https://profiles.nlm.nih.gov/ps/retrieve/Narrative/WG/p-nid/149",
"https://www.sciencedirect.com/science/article/pii/0014579380805643"
],
[],
[],
[],
[],
[]
] | |
388lc8 | Question about Galvanic Corrosion, Do the metals need to touch? | From everything I have read about galvanic corrosion it always states 3 main things need to occur,
1. Dissimilar Metals
2. Exposure to an electrolyte
3. Direct contact between the metals.
My question comes in on the 3rd point about direct contact. Say I have Stainless Steel 304, and 6061-T6 aluminum in a salt bath very close to one another, but not touching, does this mean that galvanic corrosion will not occur? Wouldn't the impurities in the salt water act as a conductor between the 2? Or do I have to have them touch each other, or via a wire?
Thanks for your input, it’s been bothering me now for a while!
| askscience | http://www.reddit.com/r/askscience/comments/388lc8/question_about_galvanic_corrosion_do_the_metals/ | {
"a_id": [
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"text": [
"Yes they need to touch, or you need to run some kind of electrical conductor from one to the other (that is not the electrolyte). The process works as a cycle, ions travel from one metal to the other one way through the electrolyte and the charges are balanced out by electrons traveling through the electric connection. If you remove the path for the electrons then you remove the ability for ion migration and the corrosion to happen."
]
} | [] | [] | [
[]
] | |
2ynm70 | How noisy is it on the surface of the sun? | Is it the loudest place in our system? | askscience | http://www.reddit.com/r/askscience/comments/2ynm70/how_noisy_is_it_on_the_surface_of_the_sun/ | {
"a_id": [
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"So going of off u/Jellyman87 numbers (150dB on earth, sun 149,600,000km from earth) I did some quick searches and whatnot.\n\nUsing this formula; [Lp2 = 20 log (R2 / R1) + Lp1](_URL_1_) with this input; 20log((1/149,600,000,000))+150, I got that the surface of the sun would experience **373.5 dB**.. Which is ridiculously insane. \n\nAs a quick check, I put 373 as noise input level and the immission point at 149,600,000,000 meters [here](_URL_0_) and got that the listener on earth would experience 150dB\n\n\n\nAnyone who actually has some form of formal education in physics and or math, please check and correct me here if you got the time.\nI don't even know what the \"log\" part in the formula really means (logarithm or something?), and there's a good chance I oversaw something vital and obvious.",
"A proper answer should involve the acoustic properties of the solar atmosphere. Speculative questions/answers involving filling space with a medium to propagate sound should be directed to /r/AskScienceDiscussion instead."
]
} | [] | [] | [
[
"http://www.engineeringpage.com/calculators/noise/distance_dB(A).html",
"http://www.engineeringtoolbox.com/inverse-square-law-d_890.html"
],
[]
] | |
caxsum | How were consumer goods marketed in the Soviet Union? Were there television advertisements or catalogs? | In Western countries, we obviously have TV ads, radio ads, catalogs, newspaper ads, billboards, product placement, everything under the sun. I know the USSR didn't produce a huge number of consumer products like toys, but for those that were produced, how were they marketed? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/caxsum/how_were_consumer_goods_marketed_in_the_soviet/ | {
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"I'll focus on a particular sliver of Soviet history (the 1920s and 1930s) and specifically print media in that period, but, in short, there were advertisements for consumer goods, although advertisement placements were restricted far beyond what an American consumer would be used to.\n\nIn this period, advertisements for consumer goods, especially newly-introduced consumer goods (often based on European or American products) were more of an educational nature, as often such goods were unavailable in shops. It was less that Soviet citizens should go out and start buying them (often this was impossible), but rather that they should know that such goods existed and expect them as part of a new, cultured life in developed socialism. This was part of a broader campaign in the period to (yes, very ironically) inculcate more traditional middle-class values and mannerisms among peasants and workers. Often, much of this was based on public health and polite behavior: Wash your hands with soap! Don't spit on the floor! This was part of a general push for Soviet citizens to become more \"cultured\", including becoming literate and having a knowledge of Russian literature and arts. But knowing about new consumer and household goods (curtains, tablecloths, lampshades) was part of that general campaign for culturedness. Much of this advertisement was directed specifically at Soviet women, as they were treated as arbiters of household taste.\n\nAn example quoted by Sheila Fitzpatrick for that champion of consumer condiments, ketchup:\n\n > \"In America a bottle of KETCHUP stands on every restaurant table and in the pantry of every housewife. KETCHUP is the best, sharp, aromatic relish for meat, fish, vegetables an other dishes. Ask for KETCHUP from the factories of Chief Canned Goods Trust in the stores of Union Canned Goods Distribution syndicate and other food stores.\"\n\nA final note is that product demonstrations by sales personnel in stores and at trade exhibitions also acted as a version of in-person advertisement, and especially at the exhibitions Soviet citizens could see consumer products, such as automobiles, cameras and washing machines, that they would have extreme difficulty obtaining in everyday life. It's a bit after this period, but the famous \"Kitchen Debate\" between Khrushchev and then-Vice President Richard Nixon was at one such exhibition in Sokolniki Park in Moscow in 1959, although in that particular instance it was specifically an exhibition of US consumer goods.\n\nSource:\n\nSheila Fitzpatrick. *Everyday Stalinism*"
]
} | [] | [] | [
[]
] | |
byt934 | why does there not seem to be any solitary source for nutritional/diet information that isn't a wide variety of conflicting advice or obvious pseudo-science? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/byt934/eli5_why_does_there_not_seem_to_be_any_solitary/ | {
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"It’s a combination of things. First, basic nutrition is pretty simple and everyone largely knows it. Eat more vegetables, eat less meat, eat less processed foods, drink less soda, that kind of thing. Those kinds of things aren’t very interesting to write about because you can describe them in like one sentence.\n\nBut more importantly, people want easy answers or tricks, not straightforward obvious advice that requires potentially restructuring their entire diet. Telling someone to eat more vegetables doesn’t get a lot of hits, it’s boring advice and they don’t want to eat vegetables. What people want to hear is how to have a good diet and still mostly eat all the same things they’re currently eating. There’s no real way to do that, so people come up with lots of fancy diets and pills and whatnot and justify it with pseudoscience, because that’s what people reading diet websites are looking for."
]
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[]
] | ||
4l51ki | Colonial Era - Were the Dutch truly tolerant, or just 'business'? | I've read somewhere that the Dutch were the most tolerant during the colonial era. But considering they had a large influence in the spice trade, and it being a small nation, wasn't it just business or a choice made by its environment? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/4l51ki/colonial_era_were_the_dutch_truly_tolerant_or/ | {
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"In the 17th century the Dutch were more tolerant than other European countries. This was a result of of how the country was formed and how society was organised.\n\nThe Dutch Republic became independent at the end of the 16th century. Philip II, king of Spain and lord of the Netherlands, had introduced several impopular measures such as increased taxes, less power for the cities and the nobility, and - crucially - a ban on non-catholic religious beliefs. The relative importance of these factors may be debated, but all played a significant role in sparking the Dutch Revolt which resulted in the Dutch Republic.\n\nIn the Netherlands, protestantism was wide-spread. Especially in the western provinces, a significant portion of the population - including nobility and wealthy merchants - had protestant beliefs. Other provinces remained mostly catholic. Philip II's persecution of protestants led to civil unrest which swept the provinces. In response, Philip sent an army from Spain to put an end to the unrest and to root out protestantism. \n\nAs it happened, the unrest had mostly died down by the time the army arrived, but the arrival sparked new unrest and even open revolt by some cities (mostly in the west) and nobles. This revolt was led by William of Orange. It cost a lot of money to maintain the army in the Netherlands and after about a decade Philip was unable to keep up with payments. The result was a mutiny of the Spanish soldiers, who started sacking local towns and cities - even in the catholic provinces. \n\nThe mutiny led to a treaty by all 17 provinces in the Netherlands declaring that they wanted the Spanish army to leave and the old political situation restored. Moreover, they declared that *they*, not the king, would determine how religion would be organised in the Netherlands. This was a sticky and divisive issue though, so they didn't do anything more than declaring that they would determine it at some point in the future. Three years the provinces split over this issue. The southern provinces decided to only allow Catholicism and to stay loyal to the king, the western provinces decided to form a \"closer union\" (effectively a new country) and allow freedom of religion.\n\nThis explains the religious tolerance of the Dutch Republic. Note though that 'freedom of religion' only meant that the state couldn't force people to adhere to a certain religion. It did not mean that all religions could worship openly. For instance, some provinces and cities banned catholic churches (the buildings, not institutions); in those places Catholics had to congregate in attics which were repurposed (and redecorated) for their worship services.\n\nThere was more than religious tolerance though. In other European states kings and princes had control over the press and universities. It was difficult to publish ideas which ran counter to the ideas of the king. In the Netherlands, there was no king to stifle the exchange of ideas. Many European scientists and philosophers went to the Dutch Republic for this reason. To name just a few: René Descartes wrote his important works while living in the Netherlands; John Locke lived in the Netherlands for several years after things got to rough for him in England; Voltaire published a book which was banned in France via a Dutch publisher.\n\nTo answer your question, the Dutch were actually \"truly tolerant\", at least compared to other European nations. Of course this also helped their business. Whereas other empires had a strong religious component, attempting to convert the local populations, the Dutch were content with trading and running plantations (with the associated subjugation, slavery and other atrocities - but not forced conversion of entire populations). For example, one of the reasons the Dutch were the only ones allowed to trade with Japan was that they didn't proselytize."
]
} | [] | [] | [
[]
] | |
42itth | Is there a connection between the changes in the cinematography of Pornography and changing social norms surrounding sex? | I'll confess, I did submit this question a wee while back, and it didn't get too much traction - but I know there are folks with backgrounds in gender studies, obscenity, cultural history and the like who post here sometimes, and I think it's a fairly interesting question c:
The question occurred to me after a discussion on whether the (seeming) rise in preference for camshows and 'amateur' videos was related to a desire to reclaim authenticity re: 'real' sex.
As a follow up question: has the rise of globalisation and mass communication lead to a 'smoothing over' of styles? Were there historical differences in subject matter and film making technique which were idiosyncratic to certain countries or major production companies which fell out of fashion or were discarded?
Ta.
Edit: cheers to sowser for his brisk moderating efforts c:
| AskHistorians | https://www.reddit.com/r/AskHistorians/comments/42itth/is_there_a_connection_between_the_changes_in_the/ | {
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"So there is of course an historical component here, but I would point out that you are missing out on the past 20 years, which of course are going to have potentially a huge impact given the rise of internest pornography, so I would recommend X-posting to /r/AskSocialScience."
]
} | [] | [] | [
[]
] | |
16ckbv | zeno's infinite series paradox. | [Wiki page.
](_URL_0_)
I understand the basic idea of Zenos paradox, in that if you move your finger to touch a pencil, you can get infinitely closer to that pencil without touching it, basically rendering motion and actually touching an object useless.
Ex: (1/2inch, 1/4 inch,....., 1/40000000 inch,..., 1/100000000000inch....) Assume you are moving closer to an object.
What I don't understand, is how can I still touch, pick up and use the pencil? What proof is there that this is wrong?
This also reminds me of the paradox in which you can't actually pass an object that starts ahead of you, even though you are moving faster.
Thanks | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/16ckbv/eli5_zenos_infinite_series_paradox/ | {
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"text": [
"Well, the proof that it's wrong is that you *can* touch a pencil.\n\nIt turns out that, when you sum up all those fractions of inches, you don't get infinity. Instead you get 1."
]
} | [] | [
"http://en.wikipedia.org/wiki/Geometric_series#Zeno.27s_paradoxes"
] | [
[]
] | |
29w6r1 | " Two Native Americans landed in Holland in 60 B.C." Is this true? | The newest [article] (_URL_2_) on _URL_1_ claims that two Native Americans crossed the Atlantic and landed in Holland in 60 B.C. Their source is simply this [book.] (_URL_0_)
Can anyone here verify this? I've never heard anything like this.
| AskHistorians | http://www.reddit.com/r/AskHistorians/comments/29w6r1/two_native_americans_landed_in_holland_in_60_bc/ | {
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"text": [
"That same question was asked here a while ago, [this](_URL_1_) or [this](_URL_0_) thread should help you.\n\nThe consensus is that no, they really didn't, though subcontinental Indians may have.\n\n"
]
} | [] | [
"http://books.google.com/books?id=hBY_tIqFBysC&pg=PA4&dq=Native+Americans+shipwrecked+in+Holland&hl=en&sa=X&ei=dQqqT4WUE4KL2AXhjqGmAg&ved=0CDkQ6AEwAA%23v=onepage&q=Native%2520Americans%2520shipwrecked%2520in%2520Holland&f=false",
"Cracked.com",
"http://www.cracked.com/article_198... | [
[
"http://www.reddit.com/r/AskHistorians/comments/tocco/how_accurate_is_this_article/",
"http://www.reddit.com/r/AskHistorians/comments/25m6nc/two_native_americans_landed_in_holland_in_60_bc_i/"
]
] | |
68j7wv | What did American Indians smoke? | This is just something I have always seen in text books and films but I was never sure exactly what they were smoking. | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/68j7wv/what_did_american_indians_smoke/ | {
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"text": [
"This answer to [a similar question last year](_URL_0_) may help; although it focused on the type of tobacco found in North America and not on the application/use. "
]
} | [] | [] | [
[
"https://www.reddit.com/r/AskHistorians/comments/36qdge/is_there_a_difference_between_modern_tobacco_and/"
]
] | |
5h8c3e | why some people suffer from clinical depression and others don't? is there difference between brains? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5h8c3e/eli5_why_some_people_suffer_from_clinical/ | {
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"If you can fully solve this you'll likely be up for a noble peace price. No one 100% knows. Cognitive Psychologists believe it has to with the person's upbringing and their outlook on the world. Most of us grow up thinking that good things happen to good people and bad things happen to bad people. But once you realize that's not 100% true it can lead to depression, depending on how you cope. There's also other theories based in different psychological branches. As far as the neuroscience aspect, no one really knows and our knowledge of the human brain is minimal at best. We have some knowledge, like what is bad and good for brain. But when it comes down why something isn't right, we just don't do not know, since it varies from person to person. "
]
} | [] | [] | [
[]
] | |
4945fn | When were backpacks invented? | I once heard that backpacks are a remarkably recent invention (like post-1700). Is that true? What is the earliest known example of a backpack? By backpack I mean a large pack carried by straps over each shoulder. | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/4945fn/when_were_backpacks_invented/ | {
"a_id": [
"d0owaie"
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"score": [
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"text": [
"There is evidence to suggest that the \"Ötzi\", the name given to the ice-preserved man found in the Ötztal Alps in 1991, had a backpack - and indeed, quite a sophisticated one, with a frame.\n\nSee more detail on it here: _URL_0_\n\nÖtzi lived around 3,300 BCE, so he's probably a good contender for the earliest such device.\n\nBackpacks (strictly, wicker baskets with shoulder straps) can also be seen in a number of medieval images - most notably one from the Maciejowski Bible, which dates from around 1250."
]
} | [] | [] | [
[
"http://www.iceman.it/en/node/283"
]
] | |
1343ro | (Not trying to be rude/ insensitive), What are the reasons why Hitler is more of a villain than other mass murderers (Stalin, Mao) ? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1343ro/not_trying_to_be_rude_insensitive_what_are_the/ | {
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"Hitler set up industrial, human-killing factories and used the most sophisticated computers of the time to track the human inventory to ensure that the killing was going as efficiently as possibly.\n\nStarvation, massacres, and political purges are easy to understand. The Nazi death camps, however, were a vile insult to human dignity. The victims died like cattle. Worse than cattle in some ways because at least cattle are fed well first.\n\nImagine you are a rancher who is used to slaughtering animals and eating them. Sometimes, in drought years, you've even had to slaughter your whole herd and sell what meat you could get off them at a loss because you could not afford to keep them. Then imagine one day you discover a slaughterhouse where the animals are kept in tiny pens. They are not fed, and many drop dead from starvation. The ones who can hold out are periodically fed into the slaughterhouse machines: killed, gutted, de-boned. Then the corpses and assorted parts are cremated so no one gets to eat them.\n\nThat's what horrified the world. We're used to killing, even terribly unpleasant killing. But that was too much.",
"An important thing to note is that Stalin and Mao were around far longer than Hitler was. Hitler was only in power for 12 years, and almost all of his killing came in the last 6 years of his rule. In such a short amount of time he managed to wipe out over half the Jews in Europe and started a war that killed tens of millions more. I would argue that Stalin and Mao--murderous thugs they certainly were--did less damage to the world during a longer period of time in power.",
"Everyone in the UK/US/Aus/etc was glued to information about the war, what hitler had been up to was uncovered by the armies of those countries and broadcast as a reason why the sacrifices had been necessary, 'this is the true face of our enemy'. \n\nOther incidents have primarily been internal, as far as I know. We are aware they were/are going on, but the public interest isn't there like it was during WWII and they don't garner as much attention.",
"I'm going to preface this by noting that is is a polemic, and very biased, but I've found Cesare's *Discourse on Colonialism* a very useful tool in thinking about why Hitler is so reviled in the Western World. The full text is available [here](_URL_0_).\n\n > [what the White European Christian cannot forgive] Hitler for is not crime in itself, the crime against man, it is not the humiliation of man as such, it is the crime against the white man, the humiliation of the white man, and the fact that he applied to Europe colonialist procedures which until then had been reserved exclusively for the Arabs of Algeria, the coolies of India, and the blacks of Africa. \n\nWhat Cesaire is saying is that is not Hitler's methods-because the British used them against the Boers, or various other countries against their colonized people-but the fact that Hitler used these methods on white people. \n\nThis is not all of the answer, but do realize that it is some of it.",
"Okay, here we go for a second time as I feel I probably didn't get my point across properly earlier. I find this whole \"who was worse\" kind of argument actually very frustrating because people find it hard to look at these things with an analytical point of view. I hope you all appreciate I am in no way denying, belittling or god forbid implying any kind of support for the actions or individuals involved, in what amounts to the worst crimes man has ever committed. However the truth in these situations is very, very important and I feel like emotion in this thread ( while completely understandable) is overriding the original question and chance of getting an objective answer which is what OP wants. On my phone so excuse formatting.\n\nFirst of all I am going to answer why we perceive Hitler to be worse than the others ( especially in the West) This is largely a result of wartime diplomacy, if we are discussing the Stalin/Hitler comparison. We, the western allies needed the 2nd front in Europe that the Russians provided, at the end of the day the war would never have been won without it. Therefore it was not political to broadcast to our population that our wartime ally Uncle Joe had in fact killed vast amounts of his population through failed agricultural projects, had squashed ethnic minorities or nationalist movements in many soviet states ( i.e the Ukraine, remember large numbers of Ukrainians actually joined the Germans as quickly as they could when Barbarossa rolled up because they viewed the Russians as a greater threat) \n\nGetting down to hard figures, we're talking about 3 Million dead in the Ukraine due to food shortages, then after his Kulak program ( essentially targeting a sort of upperclass peasant) and the military purges we can add another million on top of that. Adding to this the death figures for the Gulags just in 1941-1943 ( around 500,000) and we've reached almost half of number of innocent non-coms that were killed as a result of Hitlers policies ( usually agreed to be around 11,000,000) **I am going to pause here and agree with you, this is an absolutely grotesque way of measuring this** but i feel it's important to get some context. \n\nWhile I am no expert ,Mao's failed agriculture policies and the cultural revolution also entailed mass starvation and the creation of the concept of a \"state enemy\" who to be removed ( this concept is in no way unique to the Holocaust and it's important to remember that) His reign directly resulted in the deaths of ( and this is usually thought of as a conservation estimate) around 40,000,000 people. So before you say Hitler was responsible for the most deaths etc,**that's just not true.** Not raising an outcry about these events ensured the Sino-Soviet split went ahead without interruption and the chinese were not driven back into a unified communist position by interfering western countries. Ignoring the horrific consequences of the Cultural revolution also made it a lot smoother for Western powers to start trading with China after Mao died. \n\nThe Holocaust is burnt into the Western mind in many ways. Stories told by returning soldiers, dead villages in Poland and Eastern Europe, Hollywood, the remains of the camps, and of course, the State of Israel. We only think it is worse because we have been told it is worse, because we don't know any better. Hitler is considered the Arch Tyrant because people don't understand the long term violence Stalin and Mao did their countries or others because they don't encounter it. When was the last time you saw a film about the Katyn Masscre or of the suffering of the middleclass chinese in the infamous reeducation camps ? They just didn't really exist officially until very recently, that's why, while we in the West had the whole cold war to find out about just how bad Hitler's Germany was. \n\nIt's all a game of post WW2 diplomacy. Hitler's germany was defeated, they did not need to be pandered to. To publicise what was done also the West gave a justification for horrendous 6 years they had been through and also importantly we were all of the country and it was impossible to hide. While Hitler was undoubtedly the most mechanical, he was in no way **more** evil. But from a pratical point of view the Nazi's used the infrastructure that was available to them, would Uncle Joe have done the same had he been able to? Of course he would have, don't be so ignorant as to assume just because it didn't happen, it couldn't have done had things been slightly different. After all the Final solution was exactly that, it was only really considered after it became apparent there was no other way for the Nazi's to rid themselves of the \"undesirables\" It's also about understanding. Mao and Stalin's enemies are often an abstract concept such as \" an enemy of the people\" rather than a specific ethnicity or religion ( although look at modern China and the Muslim minority or the Russian treatment of the Cossacks for a different perspective on my comment there) **As I said earlier, Hitler is considered the worst because we have more information about him, essentially because Hitler is the only one who lost.** He's not the worst because of how he killed, how many he killed or who he killed. \n\nFinally I felt I had to address some of the language that Labrutued has used in his description of the Holocaust experience. Your argument that Hitler is more evil just because of his methods is not just wrong, it's actually disgusting. You also actually opened up your 2nd paragraph with the statement **\"starvation, massacres, and political purges are easy to understand\" That blows my mind. You further go on to state the Nazi Camps were reviled because they were an insult to humany dignity, what do you think the Gulag was, the chinese reeducation camps, the entire Kyhmer Rouge regime, the infamous japanese war time hospitals or even the North Korean camps of today. Essentially, you have dismissed the 40,000,000 dead chinese, and 20,000,000 ( the usual census) deaths caused by Stalin. That's vile, and actually you should be ashamed of that statement, while I am sure you meant it in good (?) faith it's a incredibly cruel thing to say. Downvote yourself or forever be damned by your ill-gotten Karma. \n\nI am going to break things down once more to cap this off, Hitler is not and should not be considered worse because of his targets, methods or numbers. Hitler is only considered worse because of WW2 and cold war Politics ( regarding a certain kind of political blindness regarding the acts of other dictators) **As I said earlier, he's only worse because he lost and we we were found out the full extent of his madness.** in terms of real numbers what he actually did pales in comparison to Mao and Stalin but thats not the point, The point is, he's only \"worse\" because he was caught. I feel Hitler himself actually summarises his own thoughts on the subject when, after being asked what the Western powers would do when they found out about the persecution of the Jews he replied,**\" Who now remembers the Armenians?\"** (_URL_1_) \n\nI'd like to finally finish with something I said earlier, innocent Peoples lives are worth just as much, however or why ever they die. \n\n\n**EDIT** Here are some sources,\n\n_URL_0_ Discussion of Soviet policy regarding the famine and argument in favour of the idea they were in some way responsible.\n\nThe Foreign Office and the famine: British documents on Ukraine and the Great Famine of 1932-1933.( This is a good insight of Western awareness of the Famine. Various Authors, 1988,. \n\n\nMao's Great Famine: The History of China's Most Devastating Catastrophe, 1958–62, Frank Dikötter, 2010, for all information regarding Mao in this. \n\nMemory, history, and the extermination of the Jews of Europe, Saul Friedlander, 1993, for a lot of the numbers and base information about the holocaust. \n\nAuschwitz and the Allies, Martin Gilbert, 1981. \n\nThe Holocaust: Problems and Perspectives of Interpretation, Donald Niewyk, 1992\n\n\nThanks",
"While c0ldworld's answer is excellent, I would like to add that at the time, a large part was the simple shock value. Germany had made huge contributions to the arts, philosophy, etc. The deaths cause by Japan, China, Turkey, even the Soviet Union were horrific but the western nations didn't really expect much better. To give a more modern example (and hopefully make my point clearer), there were outcries (by the public, if not by governments) about the Rwanda genocide but there wasn't much of a \"Holy shit!!! *Rwanda*??? Has the entire nation gone mad???\" For a better idea of how people reacted at their core, it would be a good idea to think how we would react if we suddenly found out Canada was doing it. It combines being shocked by the idea that another \"civilized\" western nation could be so horrific with the realization that the only thing separating us from them is national tragedy and a charismatic leader. We can find a scapegoat easy enough.",
"Since we're on the topic of the Holocaust, let me remind everyone that (a) your unfounded speculation or reposting of already-given answers is unwelcome, and (b) you need to cite sources to support your arguments, and these sources MUST be peer-reviewed, from legitimate institutions.",
"By focusing on the Holocaust we might underrate a different factor: The simple reason that the narrative powers (England, USA, France, democratic Germany, socialist Germany, etc) of \"our\" (as in, the world of a random person in Damascus might not feature Hitler as main villain) world were at war with him. \n\nI'm convinced that Hitler would be less of a pop-culturally villainous figure if he would have not started World War 2 but still had the Holocaust, etc to his name. \n\nAnother factor might be that Germany is/was more in the focus of the world than China, Cambodia, Russia or African states."
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4prqwb | if someone poored the equivalent in mass as our sun, of water on to our sun, what would happen? | First off if this has already been asked can someone link me to the post? I have searched this sub but perhaps didn't use the correct key words in the search.
So yeah, just got asked this by my mate, he wants my honest opinion but I would rather know the facts instead of having an uneducated honest guess.
Thanks in advance. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4prqwb/eli5_if_someone_poored_the_equivalent_in_mass_as/ | {
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"Well the sun wouldn't go out. It would actually burn brighter. Water molecules are two parts hydrogen and and one part oxygen. The sun uses hydrogen to burn (hydrogen makes up most of the sun's mass) so by adding water you'd be adding more fuel. "
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3vrx6c | why do some peoples pinkie fingers automatically raise up when doing things? | Especially when holding a cup, typing, playing a piano, using a trackpad or occasionally even when writing or drawing things. I know it's some sign of "being fancy", but why does it happen by reflex? In my case, it's most common in my right hand. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3vrx6c/eli5_why_do_some_peoples_pinkie_fingers/ | {
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"I do this too and have no idea why. I suspect it's a reflex due to not having a good place for my pinkie to be, I have larger hands and most cups and glasses I use aren't big enough to have space for my pinkie to sit comfortably. My water bottle is larger and my pinkie does not pop up when I drink from that. \nTL;DR auto-fancy taking over.",
"The fingers share a common muscle connection that goes up into the forearm. This makes them generally move together. The pinkie is connected to both the shared muscles as well as its own set of muscles. The pinkie's movements are a balance between the shared muscles and the dedicated muscles. The relative strength & flexibility between these muscle connections will determine where your pinkie naturally wants to go compared to the other fingers."
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1pzstu | do objects really have an inherent color or is their color actually dependent on the light from the sun? | This is truly embarrassing that I don't know this, but I've always feel like I'd be chastised for asking it publicly.
So I know that the sun emits light which carries with it the visible light spectrum (ROYGBIV) and I'm told that this is what gives objects their color. So is an apple actually red (physically, within it's pigment) or is it just a gray item that appears red, like an illusion? If there was ever such thing as an objective lens or eye, would it see a true color or just some grayscale shape?
I'm aware that the cones and rods in our eyes (di, tri, poly-chromats) also determine which colors we "see".
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1pzstu/eli5do_objects_really_have_an_inherent_color_or/ | {
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"The color of an object is defined by which wavelengths of light they reflect. A blue ball for example absorb all wavelengths except for blue, which it reflects. \nThe sun comes in to play because it's what makes the light, but the surface of the object it shines on defines the color of the object. If the sun produces none of the wavelengths that an object would reflect, then the object would have no color (be black to us).",
"So let's start from the brain and work backwards.\n\n* Our brain interprets various patterns of signals from the optic nerve as different colors.\n\n\n* Stimulation of the cone cells in our retinas are what create the aforementioned patterns of signals in our optic nerve. We have three types of cone cells, each responding to a different wavelength of light, and triggering different ones at different intensities create different signals in the optic nerve.\n\n* The three types of cone cells respond to different wavelengths of light because they each contain a different type of pigment. Each type of pigment reacts to a specific range of wavelengths, and will change shape when hit by a photon within that range, which is what triggers the signal on the optic nerve.\n\n* If we're looking at an apple, the photon that we're seeing came from some source, was absorbed by molecules in the apple, and then re-emitted toward our eyes (i.e. reflected).\n\n* The apple's molecules are shaped in such a way that they will absorb some wavelengths and convert them into heat, but re-emit other wavelength.\n\n* When a bunch of photons of various wavelengths from the sun hit an apple, most of them are absorbed, but some of them are reflected (i.e. re-emitted).\n\nThus the apple looks red because some photons of the correct wavelength to trigger our red cone cells hit the apple, and the apple's molecules are shaped in such a way as to absorb and re-emit them, while simultaneously *not* re-emitting photons of the right wavelength to trigger the blue or green cones.\n\nFinally, to answer your question, the apple looks red because it reflects \"red\" photons, but not \"blue\" or \"green\" (or \"whatever\") photons. I use quotes, because you can't really say that a photon is a certain color, but only that it has a certain wavelength that triggers our cones to tell our brain that we saw a certain color. However, if no \"red\" photons were hitting it, we wouldn't be able to see that it was red, because there would be no \"red\" photons to bounce off to our eyes. For instance, if it were illuminated only by blue light, the apple would look black (or perhaps dark gray).\n\nSo I guess you would be correct in stating that objects both have an inherent color *and* that their (perceived) color is dependent on the light source."
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1rk8cb | how many people had to be in agreement before the soviet union could lunch it's nukes? | I'd like to believe that the sanity of one man wasn't all that was standing in the way of human extinction for over 30 years | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1rk8cb/how_many_people_had_to_be_in_agreement_before_the/ | {
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"Well you might as well ask the same question about the USA, or any of the other nuclear powers. There were gung-ho advisors and leaders on both sides, and global security often rested on the hope of cooler heads prevailing. There were actually several instances where nuclear war was only narrowly avoided, two times by low-ranking Soviet officers: [Vasili Arkhipov](_URL_1_) and [Stanislav Petrov](_URL_2_). \n \n The Soviets actually had a system installed in the later Cold War era which made it easier to authorise a retaliatory strike: _URL_0_ \n \n The US president nowadays can make the sole decision, as can the British Prime Minister. British nuclear attack submarines carry hand written letters of last resort, whereby their captains may choose to launch an attack following loss of all contact with the Admiralty. ",
"Since we've strayed into how the US system works too, I thought this insight from [Hacking Nuclear Command and Control](_URL_1_), a research paper done for the International Commission on Nuclear Non Proliferation and Disarmament would be helpful.\n\n > The US uses the two-man rule to achieve a higher level of security in nuclear affairs. Under this rule two authorized personnel must be present and in agreement during critical stages of nuclear command and control. The President must jointly issue a launch order with the Secretary of Defense\n\nIf you want something that'll really keep you up at night, consider this from the same paper (though evidence of Perimetr aka \"Dead Hand\" is spotty, contradictory, and largely based upon admissions by former high-ranking Soviet officials. \n\n > Additionally, the alleged Soviet system known as Perimetr was designed to automatically launch nuclear weapons if it was unable to establish communications with Soviet leadership. This was intended as a retaliatory response in the event that nuclear weapons had decapitated Soviet leadership; however it did not account for the possibility of cyber terrorists blocking communications through computer network operations in an attempt to engage the system.\n\nPerimetr [allegedly became operational in the 1970s](_URL_0_) but essentially amounted to a dead man's switch for nuclear launch. The Soviet command structure would activate Dead Hand as tensions mounted and then Dead Hand would require constant affirmative orders from the command structure in order to **prevent** launch.\n\nIt's difficult to find much information on the exact procedures the Soviet Union used for launch control and it becomes more difficult the further back into the Cold War we go. Partially that's because of institutional Soviet secrecy and partially it's because there were fewer and fewer physical and electronic safeguards in place. Launch authority doesn't mean much when possession of the weapon constitutes the only barrier to setting it off.\n\nWe know a good bit more about the late Soviet and early post-Soviet command and control structure. Here, from [a document from the Federation of Atomic Scientists](_URL_2_), is a description of how launch control worked roundabouts 1991. Note that given the complexity of revising such a system we can probably safely assume that it worked this way prior to 1991 though the names of the offices involved were different.\n\n > According to American and Russian sources, the command and control system for all strategic and tactical nuclear weapons is centered in Moscow; this central command authority would have to authorize the use of any of those weapons. The release and dissemination of nuclear weapons authorization and enabling codes begins at the top of the political and military establishments in Russia. The President of Russia and the Minister of Defense would independently generate and transmit a special code, which would be combined with a third code provided by the Chief of the Russian General Staff. This combined code would then be transmitted to the forces in the field, where it apparently would become part of the enabling codes needed to arm and launch the weapons.",
"In early days, there were not so many nukes so control was fairly lax. Some kind of lock was fitted to prevent unauthorised arming of the weapon. This is general across all the older nuclear powers. After some thought it was realised that these weapons remained quite vulnerable so both the US and the Soviets thought about technology to prevent unauthorised launch.\n\nThe technology was known as a [Permissive Action Link](_URL_0_). Wikipedia gives more of an overview [here](_URL_2_). It is essentially just a locking system that requires multiple actors to authorise a launch and will prevent unauthorised launch to the point of \"deadlocking\" when multiple incorrect access attempts are made.\n\nWe have some kind of view from just before the end of the USSR when the systems were probably at their most sophisticated and had been running since 1981.\n\nThis is an excerpt from the book: \"The Soviet Nuclear Weapon Legacy\" by Marco De Andreis, published by Oxford University Press on page 29:\n\n > The seperate codes sent by the president and defense minister travelled over a dedicated communications channel that validated and combined them, and passed them to another device that integrated the code input of the (Chief of the General Staff). Then the composite code would be sent to the [Commanders in Chief] of the forces dedicated to launch.\n\nSo three persons at the top. Note that shortly after the 91 coup attempt, apparently one person temporarily had all three codes. The commanders in chief would then be responsible for releasing the enabling keys that allowed the weapons to be armed as well as the authorisation for a launch.\n\nNote that full permission/authorisation information was further delegated but I don't actually know how. For example, on British and US submarines, they have the ability to launch a nuclear attack without authorisation, in case high-command is destroyed. This is where the launch authority is split between multiple officers.\n\nInterestingly, a pair of [Soviet launch keys](_URL_1_) were sold on eBay. They are supposedly authenticated. Although they look simple other pictures suggest dimples in the main cylinder to engage the pins. As there are two, it suggests a two man launch system where each key has to be inserted and turned within a certain time by two seperate persons. As the keys are together, it is probable that they were kept in a safe similar to that used in a minuteman silo. However this is speculation. The same book I mentioned earlier mentions that in later Soviet times, there was a twelve digit key involved and enabling and launch authorisation were separated.\n\n\n"
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"http://www2.gwu.edu/~nsarchiv/nukevault/ebb285/doc02_I_ch2.pdf",
"http://icnnd.org/Documents/Jason_Frit... | |
369ix5 | why do free wifi hotspots make you register? | Title pretty much says it | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/369ix5/eli5_why_do_free_wifi_hotspots_make_you_register/ | {
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"In many cases, this is a legal requirement.\n\nIn quite a few countries, every internet connection needs to be traceable. Hence why you need to register, often even with your phone number or identity card.",
"Often, to get your email address so they can ~~spam you~~ offer you services from their partners that may be interest. Enough people fail to un/tick the appropriate box to make it worthwhile for them.",
"Two reasons.\n\nOne, legal requirement. They need to be able to track whoever downloaded kiddie porn while sitting in their local McD.\n\nTwo, generating and then selling user profiles with personal information such as email or phone number = profit.",
"They don't care about your email address, as some posters are saying. And, in the US anyway, there is no legal requirement to have a splash page, but they usually have a acceptable use policy they want you to agree to. \n\nWhat they are doing is tracking you for marketing purposes. They track when you visit, and how long you stay at a minimum. If it's a large area, like a mall, they can track where you are, where you were, what stores you went into, etc. They can actually do this even if you never sign in, because your device's MAC address is included in the beacon packets sent to discover Wi-Fi networks, and for location they simply use triangulation combined with a high density of access points, many of which are actually passive. Newer access points are including Bluetooth radios for finer location granularity.\n\nI realize this sounds a bit tinfoil hat, but this is commercially available stuff. They don't really want to do anything with the data but find better ways to sell you stuff. Do you visit every Tuesday but missed a couple weeks? Monday perhaps a coupon shows up. Did you visit the Gap but just walked through on the way to your parking spot? If enough people do that, they set up more interesting displays, tailored to your demographic. Stuff like that.\n\nEdit: here's an example of this type of technology. _URL_0_"
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3ui7ni | what is a gun show and how does it work? why are people opposed to them? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ui7ni/eli5what_is_a_gun_show_and_how_does_it_work_why/ | {
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"A gun show is where vendors pay a event coordinator money for tables to sell their wares. It takes place at fairgrounds, meeting halls, and pretty much any space where there is room.\n\nPeople are opposed to gun shows because they believe you can buy anything there, illegal or legal with no paperwork. This is both true and false. In most states transfer of firearms between citizens in a private sale is completely legal, but 90% of the time vendors at a show are licensed sellers and perform a background check.\n\nMost of the private sellers, at least around here, sell over priced antiques or rifles that have been beat to hell no one wants any more.\n\nAlso, the ATF usually has a presence, either overt with a booth or covert with agents trying to sell illegal things to vendors or catching vendors turning over guns too fast after buying them from someone."
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1iyjkt | can a healthy woman with no income get obamacare? how does one get it? | I'm just visiting, but these questions were posed. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1iyjkt/eli5_can_a_healthy_woman_with_no_income_get/ | {
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"Depends on the state.",
"Obamacare isn't a thing you can get, it's a nickname for a huge law.\n\nBut if you don't have any income you should already be eligible for medicaid, if not that you can probably get your health insurance paid for or partially paid for through the healthcare exchanges. The system is designed so that the poorest of people don't have to pay (or pay much) for healthcare."
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1z4b8n | Can bacteriophages cause disease in humans by killing our bacterial lawn? | Thanks! | askscience | http://www.reddit.com/r/askscience/comments/1z4b8n/can_bacteriophages_cause_disease_in_humans_by/ | {
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"I hate to give such a non-response, but the truth is that we don't know. Right now, all the scientific community can offer are educated guesses. \n\nWhat's known is that bacteriophages in the intestines seem to favor the lysogenic cycle rather than the lytic one, reducing their direct effects on the size of the bacterial population.\n\n\nSome sources: \n\n_URL_1_\n\n_URL_0_ "
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1qww57 | From an evolutionary stand point is live birth more beneficial than laying eggs, if so why, if not why did live birth arise? | askscience | http://www.reddit.com/r/askscience/comments/1qww57/from_an_evolutionary_stand_point_is_live_birth/ | {
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"Both have their advantages. Laying eggs saves the mother from needing to carry the fetuses for an extended period of time during gestation, and is 'cheaper' in a metabolic sense. Giving birth to live young is more expensive metabolically (meaning the mother will need more food) but the offspring are less vulnerable (and more mobile) than their shelled counterparts. \n\nOne of the major things that has affected the evolution of live birth is head size. One of the reasons human babies are so helpless when born while a deer can plop out and start walking around immediately is that the head size required to fit a human brain is way too big for a human female pelvis to birth. In contrast, however, a deer does not require such a complex brain and therefore it can develop to a higher degree *in utero*. This is also why babies' skulls are not completely developed at birth, because the skull literally needs to be able to squeeze through the birth canal.",
"Live births are quick events and can be done on the move. Eggs are susceptible to attacks from small mammals. And once you have a lot of small mammals eating eggs, while live-birthing their own offspring, the balance soon shifts to live births being more common.\n\nAlso, 'from an evolutionary stand point', what works, works. What is, is. Just because something is better does not mean evolution selects it. Evolution is survival of the fittest. As in \"survival of what fits\", not what is strongest or best. Just what works best in the current environment.",
"All those referring to head size and bipedal movement as reasons for early human births are mentioning an outdated theory.\n\nIn reality, the fetus is born when the maximum level of metabolism is reached in the mother i.e. the point at which the mother is unable to produce any more energy or metabolize fuel, regardless of the number of calories consumed.\n\nThis value is so accurate in predicting births that you can track the metabolism of a mother via her breathing or urine (can't remember) and estimate how long she has been pregnant. \n\nFound it:\n\"My metabolic rate was about double what you'd expect – for a non-pregnant woman. But I was five months pregnant: I was providing energy for the developing foetus too. When my metabolic rate rose to 2.1 times the normal rate, I would go into labour – my body would no longer be able to provide the energy being demanded by the foetus.\"\n\n[Source](_URL_0_)\n\n",
"Eggs can only contain so much nutrition which the fetus can use to develop before an organism has to hatch. There is a limit to egg gestation periods based on shell strength because the more nutrition material you try to cram into the egg, the stronger the shell has to be to support the weight.\n\nLive births, obviously, do not have this problem, and as such most organisms with complex brains have live births. Live birthing does, however, have the problem of size--an organism that grows too large while gestating will die during birth (possibly killing the mother) and if it is too small it will be underdeveloped and not survive. In humans the size issue is often that a baby's head is too large to fit through the hole in the pelvis.",
"Squamate reptiles (i.e., lizards and snakes) have evolved viviparity more times than any other other vertebrate radiation. The predominant hypothesis for the evolution of viviparity in squamates is that viviparity evolves in repsonse to colder temperatures. This is supported by a number of studies, including [this recent large-scale analysis across Squamata](_URL_0_). I'm wary of some of the estimated speciation and extinction rates and ancestral state reconstructions, but the correlation between temperature and parity mode is solid.",
"To expand and stress a little bit of what floppylobster said...\n\nFrom an evolutionary standpoint, If xxx-trait is better, why does this species do/have yyy-trait? is not a great question. \n\n(To play a little fast and loose with anthropomorphizing the concepts...) At no point does evolution get to look through all the possible solutions to a problem and choose the best. Rather, when a change in a species occurs, if it enhances reproduction, it may stick. \n\nSo let's say (oversimplifyingly) a species starts giving live birth, and it works well. It's gonna go on and keep working! And all further evolution will be around that behavior. Even if laying eggs works 20% better, there's no intelligent mechanism that will wait around for or design that behavior instead."
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4ljyrm | at what point did countries in the middle east become extremist muslim/militiary? | Pardon my ignorance (both culturally and historically) but I've come across some photos of Iran or Iraq in the 1970s of people (especially women) dressed in normal clothing/having fun/mixed genders fraternizing freely
I'm just wondering as to what happened/when did it start to happen? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ljyrm/eli5_at_what_point_did_countries_in_the_middle/ | {
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"In the 50s the USA pulled down a democratical elected Man (Mosadegh) in Iran from his power because he were against the interests of the west (oil privatisation) and then they placed a western-friendly dictator, the shah of Iran, who were in fact not religous but authoritarian. One time people of Iran had enough of him and they began to protest. Some demonstrators were killed by the iranian military, which led to more and more demonstrators, that in Tehran a million people stood against the Regime and the iranian army refused to shoot at them anymore. That was the time the Ayatollah came, an extreme religious leader which coordinated the demonstrations against the regime from outside of Iran. because of that the ayatollah came to power and people's clothing and behaving in public changed. Saddam Hussein in Iraq was also a western supported dictator who at the end started a war against Iran (backed by The West), lost and attacked the southern neighbour Kuwait which angered the west, this was the time he was pulled down. People in those countries suffered most of the interventions of the west."
]
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[]
] | |
1pva9w | in movies when people are pointing guns at each why doesnt one just shoot? | EDIT: At each other* | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1pva9w/eli5_in_movies_when_people_are_pointing_guns_at/ | {
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"I always guessed that it's dangerous to shoot a person holding a gun to me at point blank range because Rigor Mortis or muscle spasms can set in to the shooter immediately after his death shooting me too. \n\n(_URL_0_). \n\nThis is just my theory though.",
"* The time-honored western thing: who's the fastest draw/shooter...which gives us\n* \"You shoot me, I'll shoot you as I go down.\" Lots of people shouting that makes for good drama. :)\n* And tension.\n* Also, its a movie. Physics doesn't have to (necessarily) apply.\n* And besides, its good entertainment. Anything to draw out the moment, right?\n* Its a movie. The guns are probably filled with blanks.",
"Two major reasons I can think of.\n\n1) There is a good chance you will still get shot. When you are hit by a bullet you do not instantly die like in a video game or if you are a mook in a movie. If you are having the big stand off that is usually the hero and a major villian so even if one shoots the other can shoot back before they die. If you miss something vital you leave yourself open for a more well aimed shot.\n\n2) It is psychologically very difficult to kill someone. That is why in movies if you want to show how much of a sociopath someone is you show them cavalierly shooting someone."
]
} | [] | [] | [
[
"http://health.howstuffworks.com/diseases-conditions/death-dying/rigor-mortis-cause2.htm"
],
[],
[]
] | |
7enkpp | why do upcoming movies still say “not yet rated” when it’s pretty obvious what the rating is gonna be? | Or not be? & Why do movies take so long to be rated? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7enkpp/eli5_why_do_upcoming_movies_still_say_not_yet/ | {
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"Because \"it's obvious\" is not the same as \"this is what it actually is\". You can't legally advertise a rating that you haven't been officially given yet, since that would be lying.",
"The movie producer doesn't have the authority to show a rating until the final cut of the movie has been reviewed. The trailer gets produced and edited before that, and even though they might know by the time the trailer is showing, there isn't time to edit another version and distribute it. Teaser trailers are shown in theaters before the final cut is done, so in that case it's just impossible to have a rating. While you might envision a formula that lets anyone determine the rating for a film, that's exactly the opposite of how the system works.",
"Check out the MPAA and the doc \"This film is not yet rated\"\n\nThe MPAA is a \"non-government\" trade organization which rates films so that the government does not get involved in the film-rating business. It's \"technically\" voluntary, but not going through their process is the quickest way to make sure your film is never seen (the NR rating).\n\nThe Rating System itself is \"somewhat\" arbitrary due to how certain \"weights\" are assigned. As an example, the movie \"Romy and Micheles High School Reunion\" was rated R because it had 3~ F-bombs, but no nudity and the general content as about PG~ (maybe PG13) level. The movie Annie (the one with Carol Burnett and Tim Curry) was PG due to one \"damn.\"\n\nThat said, it's fairly obvious what movies will get R ratings... but the MPAA may demand certain scenes be removed to stay below the NC-17 mark. Likewise the producers may be aiming for a PG13 rating (like the Marvel films).\n",
"They are not allowed to display any rating until it has be officially rated. They have to go through the entire process before they can put a rating on it, no matter how obvious it may be. "
]
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[],
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1mxale | What are some examples where the United States went into a foreign country and improved the stability of said country? | Thinking of examples such as Panama. Thanks! | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1mxale/what_are_some_examples_where_the_united_states/ | {
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"Depends what you mean by \"went in\" and \"stability.\" The US presence in south Vietnam prevented its conquest by the north, does that count? And does US aid to Taiwan count as going in? But the more unambiguous cases, you have Western Europe and Japan, South Korea, Thailand, and numerous south american interventions."
]
} | [] | [] | [
[]
] | |
76c5sc | why are major and minor chords the same frequency? | I was tuning my guitar and I played A minor, and it showed up as A. so I played A major and it also showed up as A, same frequency. Why are they the same if they sound different? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/76c5sc/eli5_why_are_major_and_minor_chords_the_same/ | {
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"In music the simple relationship is that the frequency of a sound wave is its pitch.\n\nHowever, sound obeys a cool property called superposition: if you play two sounds simultaneously then you can just add up the two waveforms and that's the combined sound. This is how a single groove on a record can give the sound of an entire symphony of players playing different instruments and notes.\n\nThe idea of *just* looking at the frequency of a sound wave evokes the idea that a sound wave is just going to be a simple [sine wave](_URL_1_), but that's a really boring tone. An actual instrument will have a something that looks [much more interesting](_URL_0_).\n\nWhen analyzing such a sound it's common to look at it in terms of a sum of different sine waves. You can break the wave up and say \"that's an A at 440 Hz, plus a C at 522 Hz but only 40% as loud, plus ...\" When you pluck just a single string on a guitar you're getting a sound that contains some fundamental frequency, which is generally the lowest and strongest of the frequencies it produces, plus a bunch of overtones. That's what makes a guitar sound like a guitar and a pipe organ sound like a pipe organ, even while playing the same note.\n\nA tuner needs to be able to work with all sorts of different instruments, so it tries to pull out that fundamental frequency. When you play a chord it again tries to pull out the fundamental frequency, and it settles on the root of the chord--A, in this case--which is some combination of lowest and loudest in the chord. The fundamental frequencies for the strings playing C/C# and E are both present, as are all the overtones for all the strings, but the A is the one that the tuner is picking up. ",
"All the other answers are right, but here's the simple, simple version.\n\nYou played a chord, which is multiple notes at the same time. Your guitar tuner doesn't have a way to say \"A major\" or \"A minor\". It only listens for one note at a time.\n\nIf you play multiple notes, it's still just listening for one.\n\nIt's like if you're trying to sort apples into one box and oranges into another box, and then you find a fruit salad. Which box does it go into?\n"
]
} | [] | [] | [
[
"http://www.audioundone.com/wp-content/uploads/2015/01/1.21.jpg",
"https://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Simple_sine_wave.svg/1024px-Simple_sine_wave.svg.png"
],
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] | |
372htt | when the police offer money for information on a crime, where does that money come from? | Where does the money that Crime Stoppers and other police agencies give out to people who give information on crimes come from? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/372htt/eli5when_the_police_offer_money_for_information/ | {
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"text": [
"The department budget which is funded by tax dollars and money made back from anything like tickets, police auctions etc"
]
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[]
] | |
33qrcr | . why do people appear to have one eye that squints more than the other? | Or to put it a different way when you look at people why is one eye usually more closed/smaller in appearance than the other. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/33qrcr/eli5_why_do_people_appear_to_have_one_eye_that/ | {
"a_id": [
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"text": [
"Our faces are actually slightly asymmetrical. If you took an image of your face, split it down the middle, and mirrored the left side over the right or the other way around, you would get a face that looks off.\n\nFor the eyes, the appearance of the size of the eye often depends on the eyelid (some types of makeup applied on the eyelids try to amplify this effect). People with double eyelids (a crease in the eyelid so that it looks like two folds) look like they have more open eyes than people without double eyelids. However, the crease may be slightly different in one eye vs. the other so that one eye may appear smaller or more closed."
]
} | [] | [] | [
[]
] | |
ya9f7 | Did DNA itself evolve over time? Or was it the same as today since life first started? | All life forms have some sort of DNA, for replicating cells and reproduction, afaik. Did this process itself evolve over the billions of years, or did it work exactly the same as it does today?
If it did evolve, how? If it didn't, why not?
Thanks.
| askscience | http://www.reddit.com/r/askscience/comments/ya9f7/did_dna_itself_evolve_over_time_or_was_it_the/ | {
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"The answer is generally yes, DNA did evolve over time. The precise answer depends on the nuances of the question. \n\nIf you mean the DNA molecule itself, the question is difficult to answer and still a matter of the origins of life study. Researchers propose that DNA came to be used only after \"life\" had evolved from using RNA molecules [(see the RNA world hypothesis)](_URL_2_). We imagine things started off with some molecule that resembled nucleic acids such DNA or RNA strands (which are composed of long strings of nucelotides). Eventually, nucleic acids came together and formed the RNA molecule which then acquired function. In this theory, the DNA molecule came to be as a modification of RNA, going through several \"proto DNA\" stages like U-DNA (that contains uracil) before it became the genetic material we know today. So while DNA is and has always been DNA, other things had to evolve to make the molecule itself. [Exhaustive discussion of DNA origin here](_URL_1_). \n\nWhy? Well, evolution doesn't really have a purpose but it is hypothesized that DNA was more stable than RNA as a genetic material and could be more easily repaired, thus leading to great success of processes that used DNA over RNA. Once we arrived at the DNA we all use today, I don't think we can say the molecule itself has evolved since then. Which leads me to the next point...\n\nIf by DNA you mean the complete genetic material of cells (as in \"a person's DNA\") and how it came to be used, then extensive evolution had to occur to get from a DNA molecule to the complex DNA composition of modern organisms. The DNA molecule itself eventually evolved to form replicating units and to rudimentary chromosomes (large DNA molecules with structure). Now, [bacteria have relatively simple chromosomes](_URL_0_) while animals have [several chromosomes with more complex structure](_URL_3_). Over time, chromosomes of every organism on the planet consisting of DNA have been altered by mutations, insertions, deletions, viruses and a whole range of other factors adding and subtracting until we eventually arrive at the complexity that is life today. This evolution has allowed complexity of cells, efficient replication and repair, avoidance of errors, opportunity for regulation and various other protective measures that represent cellular fitness. \n\n* Edit - on a suggestion, I corrected/added that DNA is composed of nucleotide building blocks strung together. These nucleotides would have been derived from the nucleobases, sugars and phosphates of which they are composed. I am not sure how or if the first nucelotides were formed from these individual components, but nucleotides are nucleotides and DNA is DNA. "
]
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"http://bio1151.nicerweb.com/Locked/media/ch20/20_02a.jpg",
"http://www.ncbi.nlm.nih.gov/books/NBK6360/",
"http://en.wikipedia.org/wiki/RNA_world_hypothesis",
"http://www.biologyreference.com/images/biol_04_img0412.jpg"
]
] | |
ak53ht | how are our water pipes pressurized? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ak53ht/eli5_how_are_our_water_pipes_pressurized/ | {
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"Many cities have water towers that use the force of gravity to pressurize your water, so when you use it, it is essentially pushed by gravity to your faucet or wherever.",
"Gravity. Towns with hills will pump water up to a storage tank and let gravity do the rest. Towns with no hills... that’s where water towers come in.",
"There are a couple of different ways depending on your geography. The easiest way to keep the water pressurized is to have a water reservoir on a hill so that the water gets pressurized on the way down from the hill. The issue then is how do you get the water up the hill if there is no water on the hill. And for this there is pumps which can pump water from sources further down and up the hill to refill the reservoir. Depending on how much water is being used the water level in the reservoir might become lower but the pumps will be able to refill it over time when people are not using as much water. But the pumps can not turn on and off fast enough to match the load exactly. But there can be other issues, what if you do not have a hill to place your reservoir on. Then you just place a tank on top of a tall building or tower. This is why you often see big water tanks on top of building and as free standing water towers in towns. But then what if you can not build tall structures to mount your tanks on. It is possible to have a pressure tank in the system which is filled with air. Unlike water air will compress when pressurized. So as the pumps add water to the pipes the pressure increases causing the air in the tank to compress letting water into the pressure tank. When the demand for water is higher then the pumps can supply the compressed air will push the water out of the tank. This is a more expensive system but is an option where an elevated water tank is not desired.",
"There’s several ways. \n\n1) Water from a high reservoir is piped to a low place. Gravity does the work\n2) The water is pumped from a low place to a high place like a reservoir or water tower. Then gravity does the rest of the work\n3) Pumps without a reservoir or tower "
]
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4fjv0d | Has there ever been a case of terrorists or other actors claiming responsibility for attacks they did not carry out? | I was thinking about the possible propoganda benefits of a terror cell claiming responsibility for an attack that someone else committed, before anyone knew differently, or claiming they caused some sort of accident to make themselves seem stronger than they are. I know that False Flag attacks have happened before, but I was wondering if the reverse had happened? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/4fjv0d/has_there_ever_been_a_case_of_terrorists_or_other/ | {
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"text": [
"Unfortunately all of the examples I can think of would break the 20 year rule, but the answer is \"Yes\" it happens all the time. _URL_0_"
]
} | [] | [] | [
[
"https://newrepublic.com/article/92532/what-ansar-al-jihad-al-alami"
]
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5tau3v | why has humanity used barrels for liquids and crates for solid goods? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5tau3v/eli5_why_has_humanity_used_barrels_for_liquids/ | {
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"Solid Objects are (on the whole, on average) square or cuboid. Crates stack cuboids well. Liquids fill their container. Barrels provide good volume per surface area, but don't fit cuboids well. Barrels have a worse volume per surface area, but the liquid fits it perfectly every time."
]
} | [] | [] | [
[]
] | ||
3lucnw | How much does the weight of the space craft effect it's reentry into the atmosphere? | If at all. Are there certain trajectories for different weights or does it not really matter? | askscience | https://www.reddit.com/r/askscience/comments/3lucnw/how_much_does_the_weight_of_the_space_craft/ | {
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"Let us do a thought experiment for that: Take a normal space capsule like the American space program used to use, with a rounded bottom and conical top. There is a certain range of trajectories where this capsule will have a safe reentry. If you now scale that capsule up by a factor of two, keeping all proportions and materials the same, it will have eight times the volume and mass, but only four times the surface area of the original. This means that it has eight time the momentum (and eight times the inertia) of the original capsule, since that depends on mass, but only experiences four times as much drag, which is dependent on surface area. In effect, this means that the deceleration (in m/s^2 ) from a certain speed at a certain altitude is halved. Thus, if it followed the same trajectory as the smaller capsule, it would hit the denser layers of the atmosphere with too much speed and burn up. So yes, a spacecraft's size definitely affects which reentry trajectory has to be chosen."
]
} | [] | [] | [
[]
] | |
b93ot7 | In regards to sunscreen and its effectiveness over time. How is it "used up"? | They say that you need to reapply sunscreen every two hours but is that duration dependent on how much the sun's photons reacts with the sunscreen on your skin or is it simply that the sunscreen loses its effectiveness the longer it is on your skin? | askscience | https://www.reddit.com/r/askscience/comments/b93ot7/in_regards_to_sunscreen_and_its_effectiveness/ | {
"a_id": [
"ek2f2oe"
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"text": [
"Humans sweat and rub their skin. Over time the sun screen is either absorbed or rubs off.\n\nAside from that, it doesn’t fully block UV light; only enough so that the skin can repair any damage inflicted. Over time, the damage due to exposure increases past the point your skin can safely handle."
]
} | [] | [] | [
[]
] | |
4oqkdm | what is borax and what does it have to do with smelting? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4oqkdm/eli5_what_is_borax_and_what_does_it_have_to_do/ | {
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"text": [
"Borax is sodium tetraborate decahydrate. It is a mineral salt of boric acid.\n\nIn some smelting processes it is used as a flux. A flux is something added to the smelt to help remove impurities in the metal. Borax and other fluxes help by bonding with the impurities and causing them to float to the top where they can be skimmed off as slag."
]
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n8f36 | Can reading tiny fonts damage your eyesight? | Basically I'm looking to get an eReader of some sort and I have a lot of pdfs that have tiny writing once you put them onto a small screen. Some of them are comics, so zooming in is kinda not great... Anyway, I seem to be able to read them fine, albeit a little closer to my face than with a normal book, but I wanna know if there's anything in the literature to suggest that reading such small writing could damage one's eyesight?
Edit: Askscience answers only, please. I know my way around modern technology and have my reasons for my purchase considerations. I gave the reason for asking in case people wanted context, but I don't want advice on what to buy or how to use it. Thanks for trying to be helpful it though. | askscience | http://www.reddit.com/r/askscience/comments/n8f36/can_reading_tiny_fonts_damage_your_eyesight/ | {
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"The (currently) accepted opinion is that small fonts on eReaders/computers/etc won't cause permanent eye damage, but it will cause short term problems (tension around the eyes, headaches, fatigue, blurred vision). But there are still a lot of ongoing studies.\n\nI'm an ergonomist, so I learned about this stuff in class. If you have access to sciencedirect there are a few articles about the subject on there.",
"The (currently) accepted opinion is that small fonts on eReaders/computers/etc won't cause permanent eye damage, but it will cause short term problems (tension around the eyes, headaches, fatigue, blurred vision). But there are still a lot of ongoing studies.\n\nI'm an ergonomist, so I learned about this stuff in class. If you have access to sciencedirect there are a few articles about the subject on there."
]
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[],
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] | |
1or7e0 | If an alien satellite comparable to Voyager passed through our solar system, would we see it? | I've always been fascinated by the Voyager satellites and the images and sounds they carry on their golden records. If a technologically comparable satellite from an alien race passed through our solar system, what are the chances we would discover it?
For those interested, here are images of some of the stuff sent on Voyager: _URL_0_ | askscience | http://www.reddit.com/r/askscience/comments/1or7e0/if_an_alien_satellite_comparable_to_voyager/ | {
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"Not unless it was broadcasting a signal that we could receive. Despite being fairly large, these types of probes are tiny compared to other objects out there in space. \n\nTldr: No, unless it was broadcasting a signal. \n\n**Edit for more info**: \n\nAs an example, Voyager 1 is about the size of an SUV. That may seem fairly large but looking for something of that size in the vastness of space is pretty difficult, even if you know it's there. The chance of stumbling across one of these things is extremely low. The best way to find a spacecraft like this would be if it was transmitting a signal of some type that we could detect, such as a radio signal. To make the odds even better, it would need to pass very close to Earth. The chance of that happening is again very low since Earth isn't a very massive planet with an expansive gravity well. In a normal scenario, the only way that we would find something like this is to simply get lucky. You'd have to be looking in the right place at the right time with the right equipment to even get a glimpse of one. Even then, you'd have to follow up on it and not just dismiss it as some technical glitch. \n\nNow let's say that a spacecraft was launched in the early universe. Say, 700 million years after the big bang, so we have stars and such and let's assume life took off that quickly. Let's again say that this spacecraft traveled at Voyager 1's max speed of 38,610 mph (62,136 km/h). If it survived the ~13 billion years that followed then it could potentially have traveled 750,000 light years. Our own galaxy is 100-120 thousand light years across so it could have potentially come from anywhere in our galaxy and possibly a few of the surrounding galaxies such as the Magellanic Clouds. Even then, the odds of the craft being aimed precisely for earth and not being destroyed in its journey are unfathomably low. The odds of it still functioning and broadcasting are practically zero unless it's a technology that we don't have. ",
"Unless it came very close to Earth the chance that we would see it, visually anyway, is practically zero. There are many Earth orbiting artificial satellites that you can see with your naked eyes on any given night, but they need to be in relatively low orbits and have reflective surfaces that are oriented properly between the Sun and an observer. Geosynchronous satellites are too far away for the naked eye but can be observed with optical aid, such as binoculars or a telescope. However, this severely restricts the field of view, which means you either have to know precisely where to look or you just happen to be looking in the right place at the right time. Even though there are a lot of folks observing the night sky every evening, it is entirely possible that an object the size of Voyager could pass right by us, just above the outer reaches of the atmosphere, and not be noticed at all.",
"To add onto this question, would we be able to catch it?"
]
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6lmgla | Why didn't the Soviet Union face any threats from the west when invading Poland jointly with Germany in 1939? | I've always read that they jointly invaded Poland (Molotov-Ribbentrop pact) but this got repercusions only to Germany, which had war declared upon. Why wasn't the soviet union threatened too? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/6lmgla/why_didnt_the_soviet_union_face_any_threats_from/ | {
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"I've written about this some time back, so allow me to dig it back up, and expand slightly!\n\nFirst, lets look at the text from the [\"Agreement of Mutual Assistance between the United Kingdom and Poland, August 25, 1939\"](_URL_1_).\n\nAlthough the phrase *\"Should one of the Contracting Parties become engaged in hostilities with a European Power in consequence of aggression by the latter against that Contracting Party, the other Contracting Party will at once give the Contracting Party engaged in hostilities all the support and assistance in its power\"* would seem to be straightforward, it really isn't! There was also the Secret Protocol which stated that \"European Power\" was little more than a euphemism for Germany, and that if *another* power invaded *\"the Contracting Parties will consult together on the measures to be taken in common.\"*\n\nSo yeah, there was a big, glaring caveat, and while the invasion on Sept. 1st saw Britain fulfil what was a clearly stated obligation, on Sept. 17th, Britain was happy to stretch that language to the breaking point, no matter how much they might not have liked Soviet actions. And why wouldn't they? There was definitely belief that Soviet-German cooperation wouldn't last and they would eventually turn on each other, and a declaration of war would jeopardize that, forcing the two into closer cooperation. Poland was doomed, and Britain knew she had no chance to actually save her from this initial invasion, so what would be gained by adding another belligerent to the war? When Sir William Seeds, the British Ambassador in Moscow, was asked his opinion, he responded \"I do not myself see what advantage war with the Soviet Union would be to us, though it would please me personally to declare it on Mr Molotov.\"\n\nSo anyways, on the morning of the 17th, the Polish Ambassador visited the Foreign Office on what he really already knew was a futile mission, understanding that the British Government would (publically at least) state they had considered 'other European power' to be Italy, even though Poland, and perhaps any reasonable person, would have seen the USSR as the next biggest threat. The Cabinet met the next day to consider the matter, and prefered to do an ostrich act than play the lion, deciding simply to formally protest Soviet actions to register their \"horror and indignation\", and maintaining *\"[complete confidence that on the conclusion of the war Poland would be restored](_URL_0_).\"*\n\nPoland of course protested, communicating to Lord Halifax, the Foreign Secretary, that \"the Polish Government reserve the right to invoke the obligation of its allies arising out of the treaties now in force\", but was succinctly rebuffed, which Halifax emphasising the British interpretation of the treaty, namely that they had no obligation to do anything other than consider the matter, meant *\"we are free to take our own decision and to decide whether to declare war on the USSR or not.\"*\n\nSo within only a day or two, the Soviet action was a *fait accompli* and if anything, the British government now went on a PR campaign to try and justify its lack of action. In October, after Poland had fallen, Lord Halifax addressed the House of Lords to note:\n\n > It is perhaps, as a matter of historical interest, worth recalling that the action of the Soviet Government has been to advance the boundary to what was substantially the boundary recommended at the time of the Versailles Conference by the noble Marquess who used to lead the House, Lord Curzon, who was then Foreign Secretary.\n\n Churchill, at the time First Lord of the Admiralty, characterized Soviet action as stemming from \"cold-self interest\" but nevertheless saw them as a future partner against Germany who shouldn't be unnecessarily antagonized for no benefit:\n\n > I believe Russia will always act as she thinks her own interests demand, and I cannot believe she would think her interests served by a German victory followed by a German domination of Europe.\n\nAnd although not a member of the government, it is also worth mentioning Lloyd George's editorial in the *Sunday Express* entitled \"What is Stalin Up To?\" published in late September, which essentially justified the Soviet movement and pushed their own explanation that it was intended as a humanitarian action to protect the people who lived in eastern Poland (In the words of the Soviets, *\"The Soviet Government also cannot view with indifference the fact that kindred Ukrainian White Russian people, who live on Polish territory and who are at the mercy of fate, should be left defenceless\"*). When Ambassador Raczyński attempted to have a refutation published in the *Times*, he was rebuffed and had to arrange for private printing of it.\n\nThe sum of it is that, to quote Paul W. Doerr:\n\n > [F]rom the signing of the Nazi-Soviet Pact to the beginning of the Winter War [...] British policy-makers were driven by a profound ambivalence. On the one hand, a deep and abiding mistrust of the Soviets is easy to find. On the other, the British remained acutely aware of the grave situation they faced, and of the overriding need to retain a connection to Moscow. Such ambivalence can be found at the heart of all aspects of British-Soviet relations during this period.\n\nIt was only upon the invasion of Finland that British lawmakers began to find themselves unable to justify their inaction in the face of Soviet aggression. The onset of the Winter War was simply much harder to explain away with magic handwaving though, and in the weeks leading up to the Soviet invasion, the British were discussing how they would need to potentially react to such an eventuality. There was fear that if the Soviet did so, it would be prelude to a push further into Scandinavia, possibly threatening Norway. Some within the government went so far as to suggest that the UK should immediately declare war if such an attack came, although it was the minority view - \"ideological circles\" in Lord Halifax's words. A telegram from the British Ambassador to Finland on Oct. 21 to that effect was deemed impractical within the Foreign Office since \"the Cabinet presumably still take the line that we cannot afford to break with Russia and thus turn her into an ally of Germany\" as one commentator noted. This was backed up further by reports from the military that they were in no state to be able to lend military assistance. \n\nWhen the invasion came, obviously, war was not declared, despite significant outcry from the British public over the Soviet action. The same caution as before applied, but it was a lot harder to explain away what the Soviets were doing this time around. The British provided supplies, and there were some volunteers, but it wasn't until March that they finally felt they had no choice but to give into the public pressure and intervene. But even then, it was supposed to be a quite limited action, with the main intent to protect further incursion into Scandinavia, not just by the Soviets, but by Nazi Germany as well. The main thrust of the planned force was to occupy northern Norway and Sweden in order to prevent Swedish iron ore from falling into Nazi hands. The actual military assistance to the Finns would have been a single brigade placed in the far North, far from the key southern region where any actual impact would be felt. Obviously it all came to naught when Finland fell before it happened. This was just fine with the British as they had been incredibly uncomfortable with going through with the plan. It still was a bad blow to Soviet-Anglo relations for the next year though, and had at least some on Stalin's reluctance to trust British reports in early 1941 that Barbarossa was imminent.\n\nIn the end of course, you the UK didn't necessarily make the wrong choice (for them. Poland and Finland definitely got screwed). I don't want to deal with counterfactuals, but the possibilities for how war would have progressed if the UK and France had entered open hostilities with the USSR certainly don't seem to *improve* the odds for the Allies. The travails of Poland through the war, and beyond, are really another topic, but suffice to say that the UK continued to ignore what was staring it in the face, and continue in its (public) belief that Poland would be restored, although in part we can say that it was a continuance of their \"we need to not piss off the USSR\" policy, and when it was clear they were mistaken, it was too late and there was nothing to be done anyways, leaving us with the sad irony of the war, that it was launched on the *casus belli* of maintaining Polish independence, and in the end, Poland would spend a half-century behind the Iron Curtain.\n\nDoerr, Paul W. \"'Frigid but Unprovocative': British Policy towards the USSR from the Nazi-Soviet Pact to the Winter War, 1939.\" *Journal of Contemporary History* 36, no. 3 (2001): 423-39. \n\nKochanski, Halik. *The Eagle Unbowed: Poland and the Poles in the Second World War* Harvard University Press, 2012\n\nPrazmowska, Anita. *Britain, Poland and the Eastern Front, 1939* Cambridge University Press, 1987"
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"https://en.wikisource.org/wiki/Agreement_of_Mutual_Assistance_between_the_United_Kingdom_and_Poland-London_(1939\\)"
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9asfu0 | why a different bloodtype from every immediate member of a family can hapen if they are all blood related? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9asfu0/eli5_why_a_different_bloodtype_from_every/ | {
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"People carry dominant and recessive traits in their genes. When two people have a child, the dominant and recessive traits from both get passed to the child to some degree, with some of them dropping off, usually some of the recessive ones.\n\nWhat this means is that if you have two blond haired blue eyed parents, you're likely to have a blond haired blue eyed child. But if one of the parents has green eyes, you may end up with a red haired brown eyed child due to the interaction of the dominant and recessive traits.\n\nThe same is true for blood types. If someone O+ has a child with someone A-, that child could be A- (safest for A- mother) but could also be A+. AB- AB+ or O, based on the interplay of traits contributed from both parents.",
"This is due to each cell containing information from their father as well as their mother. Everybody has two so called \"genotypes\" and one (possibly 2) so called \"Phenotypes\"\n\n & #x200B;\n\nThe Phenotype describes the \"strong\" inherited DNA whilst the genotype describes both parts that you recieved from your parents.\n\n & #x200B;\n\nFor example: Your father has blue, your mother brown eyes. There is a big chance that you carry both these genes whilst one is more dominant than the other, so you end up with blue eyes, even though your DNA contains the info for both. so your Phenotype is Blue, yet your genotype is blue and brown.\n\n & #x200B;\n\nThese informations will be passed on to your children, so each of your children can recieve either your brown or blue eye DNA that you carry in yourself, depending on what part of the DNA your partner contributes determines your childrens eye color. Lets say your partners parents had brown and green eyes. That would yield the possibility of brown eyed, blue eyed and green eyed children. \n\nIts hard to explain (especially since english is not my 1st language)\n\n & #x200B;\n\nYou have 3 \"basic\" Blood types: A, B and 0\n\n & #x200B;\n\nLets say your father has A0 as his genotype (his phenotype is A since A is dominant, whilst 0 is so called recessive \\[weaker\\]), whilst your mother has B0 as her genotype. That could yield all 4 possible outcomes of the AB0-Bloodtype. Your parents children could be AB, A, B or 0 as their expressed Phenotype.\n\n & #x200B;\n\nIts basically 2 parts your cell carry that can be passed down from generations, of which only one can be expressed in you, but that doesnt mean that you can give these traits to your children.\n\nHere is a picture to hopefully make it clearer what Im trying to explain: [_URL_1_](_URL_0_)"
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3vb9xy | Do Aquatic Animals Yawn? | askscience | https://www.reddit.com/r/askscience/comments/3vb9xy/do_aquatic_animals_yawn/ | {
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"Fish yawn as territorial or mating displays it's commonly accepted that all vertebrates yawn. Nobody knows why though here's an article on [why we think people yawn](_URL_0_). \n\n[Here is an article about fetal yawning](_URL_1_) ",
"Cetaceans (whales, dolphins and porpoises) do not yawn. We as auto breathers yawn as a mechanism to increase oxygen in our body when the body realises it does not have enough. It is a completely automatic response that will happen even when we are completely unconscious. \n\nDue to the risks of automatically taking a breath when underwater, Cetaceans are completely in control and have to think about every breath they take. As such they have no automatic function which will cause them to yawn. This also allows them to stay on a dive much longer than humans as they can lower their bodies oxygen levels much further then we can without this automatic response. They have several other adaptations which help them achieve this state on anoxia including being able to partially shut down their extremities from requiring oxygen and having a much higher haemoglobin count so that when they breathe at the surface they can super oxygenate their blood. On top of this when they breathe they can evacuate up to 90% of the air in their lungs with one breathe, which is far more than we can. \n\nSo basically, if a cetacean is unconscious for any reason in the wild it will die."
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5afmlw | How does an RNA 'know' which DNA strand to copy during transcription? | Since RNA is single stranded, and each base codon codes for an amino acid, what DNA strand is copied greatly influences the protein being formed. If both strands had the chance of being copied then you could have two proteins being coded by one gene. Proteins which could have vastly different functions. Is my understanding correct? Bonus question: Also, since you have two copies of each gene along each chromosome? what determines which chromosome is copied? | askscience | https://www.reddit.com/r/askscience/comments/5afmlw/how_does_an_rna_know_which_dna_strand_to_copy/ | {
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"RNA doesn't know anything. ~~It's just a silly, passive molecule that does what it's told! RNA's dreams of dancing in Paris will never come true!~~ \n\nRNA doesn't know anything. Genes occur on both strands of DNA in a chromosome. Transcription of DNA into RNA occurs when RNA polymerase, the enzyme that makes RNA, is recruited to the region just upstream of the beginning of a gene. Depending on the type of gene we're talking about and what organism this is occurring in, how RNA polymerase and the proteins that recruit determine where a gene starts can vary. The general idea is that proteins called \"transcription factors\" recognize specific sequences of DNA in the upstream region of a gene. Different genes will have different sequences of DNA, and so different transcription factors will bind there. These transcription factors interact with RNA polymerase and other transcriptional machinery, which go on to actually transcribe the gene. \n\nBottom line: genes occur on both strands of DNA, and proteins figure out where to transcribe. \n\nSo far as I know transcription occurs at equal rates at each copy of a gene on homologous chromosomes. ",
"Just as an intro, DNA is made up of nucleotides, which in turn are made up of the nucleobases that you probably know about (A, T, G, and C in DNA). Each of these nucleosides contains a five-carbon sugar (deoxyribose, in DNA). All the sugars in DNA are put together in the same direction, so that the 5th carbon of one sugar bonds with the 3rd carbon of the next sugar; its 5th carbon bonds to the 3rd carbon of the next sugar; and so on.\n\nThis means that each strand has two ends; one ends in the fifth carbon (the 5' (5 prime) end), while the other end is the 3rd carbon (the 3'-end). The other strand is reversed; so where one strand has the 5' end, the other has the 3' end.\n\nNow transcription in eukaryotes only occurs in one direction: 3' to 5'. That is, the RNA polymerase moves down one strand from the 3'-end towards the 5' end. The strand it reads is called the antisense strand, because the RNA that comes out will LOOK like the other strand - the sense strand (due to the complimentary pairing of the nucleotides, except for U replacing T).\n\nNow, each strand has a direction in 3' to 5', so both can be read by RNA, as long as there is a start sequence that says \"Here's a gene to read!\". Interestingly this means that genes can overlap, and the antisense strand for one gene might be the sense strand of a different gene that reads that strand from the other direction for a different gene!\n\nEDIT: Just realised I forgot to answer your original question. RNA knows *which* strand to copy because it finds the sequence of code that says \"Here's a gene to read\", termed a promoter, which causes an RNA polymerase to bind to the strand and transcribe the code in the 3' to 5' direction, creating mRNA, until it reaches a sequence that tells the polymerase to stop."
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3jh7q0 | Where did the Chinese hairstyle of the shaved head with the long ponytail originate from? | I've been watching a lot of kung fu movies and the majority of them are set in the beginning of the 20th century. The hairstyle seems very common. Where did it originate from and what caused it to disappear? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3jh7q0/where_did_the_chinese_hairstyle_of_the_shaved/ | {
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"What you're describing was not actually originally a Chines hairstyle but rather one that was imposed on China during the Qing dynasty, the period in which those movies are set. The hairstyle, known in English as a queue, was originally a Manchu hairstyle and was something mandated by law shortly after the Manchus took control and began the Qing in the 17th century.\n\nInitially it was primarily soldiers and officials who were ordered to shave, but later it was extended to the population at large. There were a number of reasons for why this was enacted, but put simply it can be seen as cultural imperialism and has often been argued as a way of determining obedience.\n\nIt was also not just limited to hairstyle. That was just one part of a larger dress code to get the Han Chinese more in line with Manchu practices. Later on, with the fall of the Qing, the cutting of the queue was thus equally symbolic to a population now free of Manchu rule. Thus what caused it to disappear was the fall of the Qing, that it was no longer mandatory, and that it came to be seen as a symbol or an old China that the new China was trying to move away from.\n\nAlso, since we're on the topic: the Chinese dress called [qipao/cheongsam](_URL_0_) was originally Manchu fashion as well, despite now being seen as a distinctly Chinese fashion."
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4z0ezj | reason for uti burning sensation? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4z0ezj/eli5_reason_for_uti_burning_sensation/ | {
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"The acidity of your urine irritates the area of inflammation in your bladder/urethra. Water-soluble over-the-counter cystitis remedy is composed of salts that lower the acidity of your urine, which in turn lessens the irritation. "
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abj3af | why are all james bond songs similar, regardless of who the artist is? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/abj3af/eli5_why_are_all_james_bond_songs_similar/ | {
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"They all deal with topics related to Bond and the music tends to pay tribute to the original Bond theme(s) or other songs that were written for the other Bond films. For example, Chris Cornell's \"You know my name\" was inspired by Paul McCartney's \"Live and Let Die\" and Tom Jones' \"Thunderball\" two previous Bond themes.",
"I think OP’s question is more of what is it about the song that makes you know it’s a Bond song, even if you hear it outside of a James Bond movie? ",
"I imagine the producers give the musicians the musical versionof a design brief-- basically, specs for what they want the finished product to be like, so that it supports their brand. In the case of the Bond movie songs, it seems like they want something moderately slow-tempo, portentious lyrics relating to danger/espionage/sexxxxyness, and a mysterious sound-- in short, something that pairs well with the title sequence, which itself has a certain on-brand mood to it."
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j0gg1 | Does every 3-d dimensional object have a point that you can balance it perfectly on? | Say I took the Empire State Building, does a point exist on it that if I was strong enough that I could balance it on my finger? What about a car. What about a house? | askscience | http://www.reddit.com/r/askscience/comments/j0gg1/does_every_3d_dimensional_object_have_a_point/ | {
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"If you assume that your finger can't slip, then yes. If the line between the object's center of gravity and your finger is perpindicular to the ground, it will balance perfectly. Heck, that's a common defintion of the center of gravity.",
"In fact, it will have at least two. One of these will be a stable point of equilibrium and one will be an unstable point."
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2sqjs5 | what argument(s) have courts used as a "legitimate state interest" for banning gay marriage? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2sqjs5/eli5_what_arguments_have_courts_used_as_a/ | {
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"In Utah they used a variation of the \"Please, think of the children\" theme. The Utah AG's office argued to the court that the State has an interest in promoting child birth and stable families, and that same-sex marriages hurts the institution and somehow dissuades opposite-sex couples from marrying.\n\nNever mind that:\n\n* There are opposite-sex couples who can't conceive, yet are still granted marriage licenses.\n\n* Divorce rates and the number of single-parent households are higher than ever under current marriage laws."
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3hh4vk | Is the temperature of sand hotter than the temperature it is exposed to? | I am currently in Abu Dhabi on holiday where the average daytime temperature during the summer is around 43°C, but the sand on the beach feels much much hotter on my feet.
Are feet more sensitive to heat, so the sand feels hotter? Or, despite the temperature being 45°C, is the sand hotter than that? If so, how can something be hotter than the temperature it is exposed to?
Hope this makes sense. | askscience | http://www.reddit.com/r/askscience/comments/3hh4vk/is_the_temperature_of_sand_hotter_than_the/ | {
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"Well, where do you think air gets its temperature/ energy? Answer: from the Sun, like most anything else on the surface of the planet, trough radiation. The surface of the Sun is something like 5-6 thousand degrees, so the sand is not hotter than the temperature it is exposed to. Of course, it is nowhere near that hot here, because the radiation is spread out so much (inverse square law), but, still, some materials can get hotter than others depending on their heat capacity and conductivity. Air doenst absorbs as much heat as the sand and air mixes and spreads out better/ faster than sand, so its not as hot and actually cools down the surface of the planet.\n\nIn Earth's orbit, in vacuum, the surface temperature of materials exposed to the Sun can easily reach 100 C or more, because there is no air to cool the surface down. And the surfaces in shadow can get below -100 C",
"Most of the heat we experience on Earth comes from the sun, but the heat energy from the sun dissipates long before reaching us. What's left to heat us up is the radiation from the sun. Radiant energy heats things up a little differently than direct heat transfer, like a fire heating the air around it. \n\nInstead, the photons from the sun hit the molecules in the air and those molecules absorb that energy and use most of it to spit it new photons. The end result for the air molecules is that they absorb a small amount of energy from the process which heats them up a little. \n\nThe molecules in the sand do the same thing, but they absorb more energy per photon than air molecules. \n\nFurthermore, some molecules are better at transferring heat energy than others. This transference is called thermal conductivity. So, the heat that we feel is actually based on how quickly heat is transferred to our skin. Low conductivity feels cooler, and high conductivity feels warmer regardless of the actual heat energy stored in the molecules we touch. \n\nSand has a higher thermal conductivity than the gasses making up the atmosphere, thus it feels warmer when heated up. It's really a combination of these two concepts. "
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3uhbyg | How do scientists "control" variables like age, marital status and gender when they analyse their data? | It occurred to me while reading a paper that I have no idea how this is actually done in practice and how effective these measures are at helping researchers come to more useful conclusions.
Any info appreciated. | askscience | https://www.reddit.com/r/askscience/comments/3uhbyg/how_do_scientists_control_variables_like_age/ | {
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"Sometimes you can't. If people volunteering for a trial or something are of a specific group-- men over 30, who are Caucasian-- You simply have to acknowledge your spread wasn't representative. You can design a study to be as representative as possible, but then you may end up with a very small sample size. Depending on what disease you're looking at, if it's medical or pharmaceutical, it may affect a disproportionately larger size of a certain group of the population! It's a very complicated question with no solid answer. This can be more of an issue depending on the subject. In sociology, social groups or ethnicity can be much more important a factor than, say, cancer drug trials (though some races caaaan have certain predispositions to certain diseases or drugs, but that's a big ol' can of worms.)\n\nTL;DR: a lot of the time? You just have to either acknowledge the sample is not fully representative, or you try for representation at the cost of sample size. It also depends on what your study actually *is.*",
"Most experiments (including retrospective (backward-looking reviews of what has already happened) studies that aren't random controlled trials) are, at the most basic, looking at one outcome and one exposure (potential cause.) Most things have more than one cause - or, at least, more than one thing that impacts the outcome.\n\nAs an example, perhaps a scientist wants to know if eating lots of eggs causes a person to have more heart attacks. Heart attacks are not something that happens to everyone on any given day, and lots of people eat eggs and *don't* get heart attacks, while others *don't* eat eggs and DO get heart attacks. The scientist wants to know if, *all else being equal* do people who eat more eggs have more heart attacks?\n\n(This is the part where I skip the part of experiment design where we select the population, define 'heart attack', decide how we know if someone has a heart attack or not, and how we define 'eats more eggs', and how we know if a person eats more eggs or fewer eggs. This part can ruin many experiments. In real life, don't skip this part.)\n\nSo we know that in group A - perhaps all the people who work for an insurance company and eat at the insurance company picnic every month - there are 10,000 people, and 50 people had heart attacks this year. And they didn't eat any eggs at the picnic.\n\nIn group B - let's say the nurses who work for a big hospital network - there are 5,000 people, and 20 people had heart attacks this year, and they ate LOTS of eggs at the hospital birthday lunch every month.\n\nSimple math says - 20/5K is a lower rate than 50/10K, so obviously eating more eggs doesn't cause more heart attacks.\n\nHowever - heart attacks happen more often in men, period, and they happen more often in older people, period, and if the nurses are all younger women, and the insurance guys are all old guys...well, what do we know now?\n\n(It's not like we can take a million people and say \"all you guys eat eggs\" and another million *exactly the same* and say \"you guys don't eat any eggs\" and then compare the two - for starters, that's too expensive. For another, no two people are ever exactly the same.)\n\nWhat scientists do when comparing groups that are not the same is to \"normalize\" them - find the rate for relevant subgroups (age, gender, exercise, race, smoking are usual big ones for heart attacks, although exercise is hard to measure, and economic class is also important) and then adjust the numbers for each subgroup so that they match each other.\n\nIn our heart attack example, we would find the rate for males vs females, smokers vs non smokers, and the different age ranges, and then compare the results for the two larger groups as broken down by the smaller groups.\n\nWhere things get tricky is where something might make no difference (or even be positive) at a young age (or for women) and will be negative at an older age (or for men.) \n\nThe whole process of stats and the study of disease is trying to figure out how to make grapefruit, lemons and tangerines into oranges, so they can all be compared together, without accidentally making an apple into an orange along the way.\n\nThis [article](_URL_0_) and the answers may help you figure out the exact steps.",
"Wow, something I can actually help answer! Alright, I will try to describe the statistics as simply as I can. One of the simplest statistical analyses are one-way ANOVAs in which you are trying to see how much of variable B is accounted for by variable A. As an example let's say we are trying to say that higher satisfaction at work leads to better performance. I won't go too much into the statistics by explaining regression equations but basically what we are looking for is to see if people's reported levels of satisfaction account for a significant amount of the variance in those individual's performance levels. Aka if higher levels of satisfaction mean higher performance. However, you also have to think about control variables. For example the amount of time someone has worked in that position could affect their performance regardless of how satisfied at work they are. For your examples specifically, let's say that the older you are, if you are unmarried, and if you are a certain gender, you will naturally perform better at this job. So in order to conclusively say that it is actually an individual's satisfaction that is causing them to have better performance we have to rule out all of these other variables or \"control\" for them. We do this by entering them into the regression equation and seeing if satisfaction still explains a significant amount of the variance in performance even after those controls have accounted for their own variance. Control variables help us to isolate the target relationship we are trying to examine. ",
"There a few ways:\n\n\n1. Randomisation. If you take a big enough sample (e. g. 10000 people) and randomise them to two groups. Baseline factors such as gender and age should follow a similar distribution between the two groups. Studies that do this often provide the numbers of certain demographics in the groups of their study. Group A was 49.9% female and Group B was 49.8% female and so on. \n\n\n2. Selection. Most studies don't include people of every age. In many medical studies being over a certain age (e. g. 70) will mean that person is excluded. This is for a few reasons, they have a lot of comorbodities that can influence the results, if the end point is mortality they are more likely to die of unrelated causes (sorry) and more often they are not the target population for the treatment. \n\n\n3. Statistics. If the studied population couldn't be or weren't randomised then statistics can help. This is a larger topic and beyond my expertise but basically once you have found a significant outcome in a group of people you can then use statistics to analyse which variables have the greatest impact on the outcome (e.g. Age or gender) and then account for those differences in the outcome mathematically. I believe this is regression analysis. \n\n\n4. Case control study. This is a specific study. It is a retrospective study that matches people with a disease to people with very similar demographics (age, gender, location etc.) who don't have a disease. One can look for other variables that are found in the diseased group but not in the non-diseased group. Smoking was linked to lung cancer in this way. \n\n\n5. Cohort study. This is another study. The examiner takes a group of people with a similar demographic (e.g. All males born on Dec 5 1980 in Scotland) and compares them to either the whole population or another specific cohort. It can be done prospectively or retrospectively. Although it isn't randomised, one could surmise that exposures to different variables would be well spread across the cohort and population variables are somewhat controlled. Age, gender and location are all controlled from the outset in my example. "
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1guii7 | Why was the Polish "aristocrat democracy" a failure? | I recently talked with some Polish friends about history and they mentioned this form of democracy ultimately led to the disappearance of the country in the XVIII century. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1guii7/why_was_the_polish_aristocrat_democracy_a_failure/ | {
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"My experience in this topic is based around the biography of Thaddeus Kosciuszko, *The Peasant Prince* by Alex Storozynski.\n\nThe author details that in the late 18th century, the aristocracy that actually had the voting power dissolved into a very limited oligarchy. Competition within this oligarchy resulted in the king at the time selling out to the Russians and Saxony in order to maintain dominance over the other nobles. \n\nI know this is really over simplifying it, but I don't exactly want to peruse the book for the exact entries.\n\nEdit: I have now sifted through the book a bit and: Stanisław August Poniatowski was the King of Poland, and Catherine the Great was Tsarina. The two allegedly had a fling. Also, I'll just give a direct quote from the first chapter following the coronation of Friedrich Augustus Wettin, a Saxon, as King of Poland (Pre-Catherine): \n\n\"While the Saxons carted Poland's treasury back to Dresden, the mutual distrust among the Polish nobles in the Seym led to the creation of a parliamentary procedure known as the *liberum veto*. This unitary veto allowed a single representative to block any legislation unless there was unanimous consent. This pleased foreign powers who wanted to tie up the legislature with gridlock.\"",
"Polish \"aristocrat democracy\" ultimately failed due to appetites of Prussia, Russia and Austria. We can't blame however only them for partitions as Polish-Lithuanian Commonwealth was in fact a failure state - state which hardly ruled itself and attracted a lot of attention as it lied in very important geopolitical area.\n\nThe main reason why Polish-Lithuanian Commonwealth failed was lack of administration. The administration of PLC was very limited and clearly ineffective. \n\nWhat's more, PLC was from beginning of XVII century de facto \"magnat\" (very rich szlachcic who could influence politics on national and in some ways on international level) oligarchy, which blocked any possible reforms which would strengthen the power of king and the administration. \n\nMiddle class szlachta (term meaning Polish aristocracy/gentry. It's hard to precisely translate this term) feared that king would usurp power and eliminate the freedoms which they enjoyed. One of these freedoms was for example liberum veto, practice of ending the sessions of Sejm and sejmiki (regional parliaments of szlachta) when *one* of the attendees declared liberum veto and left the Sejm. This meant that session of parliament is over and Sejm/sejmik needs to be called again for another session, which lead to endless breaching the sessions without any agreement in XVIII century. Please note that liberum veto began to be used in half of XVII c. \n\nAnother permanent weakness of prepartition Commonwealth was lack of money. Money was collected from cities (this worked) and from szlachta. Szlachta was very recluctant to pay taxes, even if they were very small. The Commonwealth budget in XVIIIth century was one of the tiniest budgets of European countries. Lack of money meant lack of money for administration and army. To summarize this paragraph - Polish taxation system in XVII-XVIII was highly inefficient.\n\nThe problem was that szlachta failed to grasp, that state with non-existent army and administration, with serious political problems couldn't exist for long. Majority of szlachta in XVII and in beginning of XVIII c. isolated themselves from international and national affairs. All they wanted was to enjoy the life at countryside and enrich their households. Szlachta at this period praised the liberties of PLC. Not many people saw what historians see now - endless kings-\"magnaci\"-szlachta conflicts, inefficiency of administration and army, and rise of Prussia, Russia and Austria.\n\nI haven't said about international reasons as you wanted to know reasons of political system failure. I hope this helped you. Unfortunately, I don't know any English literature.\n\nSource: lectures about Polish history on Polish uni."
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7nozi6 | It's 9:00PM and I'm hungry but there's nothing to eat in the house. Where do I, a middle-class citizen of Rome in 130 AD go out to eat? What foods and drinks can I expect to find there? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/7nozi6/its_900pm_and_im_hungry_but_theres_nothing_to_eat/ | {
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"By middle class, what do you mean?",
"\"Middle class,\" by any reasonable definition, is a wholly anachronistic concept when speaking of the Roman world, and really doesn't get us much of anywhere. More useful, in a thoroughly agrarian society like that of the Roman Mediterranean, is the distinction between landed and unlanded individuals. Now, it's true, a large portion of the Roman population held their own little plots of a *jugerum* or two throughout Italy. These small-time farmers held just enough property to be largely self-sufficient (barring a bad harvest, always a constant threat in a pre-Green Revolution society) but not enough to be considered wealthy by any margin. \"Middle class\" would be an improper label for them, however, in that they were a localized farming class with few similarities to the modern \"middle class\" except in that they were more or less economically self-sufficient. Moreover, a scenario in which such a small-time farmer would find \"nothing to eat in the house\" is rather unreasonable--such a situation would likely only occur during a bad harvest or other circumstances of extreme economic duress. \n\nWhat we really want to look at, then, is the city, for all kinds of reasons. But within the city the economic disparity between the landed and unlanded becomes so stark as to leave little room for anything resembling a \"middle class.\" The vast majority of urban dwellers were semi-itinerant day-laborers, seeking work at the monumental building projects, the Tiber dockyards, suburban fields, etc. on a daily basis. There was never anything resembling a fixed wage at Rome, but we can extract from our evidence rather good reasons to suppose that for the \"average\" worker in the city it was only barely possible to provide the money to feed one's family, after the high cost of rent in the city. So as not to reinvent the wheel, I encourage you to read through [this](_URL_1_) thread, which should give you an idea as to the realities of living in the city for the vast majority of the urban population. A relative few, the so-called *plebs media*, owned their own shops or workshops, and could rely on a steady source of income, however slight. These individuals were also generally not landholders (though sometimes landholders, especially senators who legally could only own businesses by proxy, set their own slaves or freedmen up in such trades and took a cut of the profits) but could pay their rents steadily and could afford permanent lodgings, unlike most day-workers, who were probably forced to change tenements rather regularly, either from an inability to pay rent or to chase work in another part of the city. To speak of such individuals as being a \"middle class\" misrepresents their place in society, however. They were above the *mercenarii* that made up most of the city's population, but only barely, and though they could close down their shops (or leave them to their workers and slaves) for a day or two to participate in political activity or festivals and maintain some degree of economic security, they still generally had dangerously little in the way of savings, and had nowhere near the economic power of the modern middle class. In any case, most urban dwellers, day-laborers and shopkeepers alike, did not live in circumstances in which one could realistically find \"nothing to eat in the house.\" The urban population lived in cramped *insulae*, [which were extremely dangerous and in which the urban *plebs* were packed family-by-family into tiny, cell-like compartments](_URL_0_). *Insulae* had no hearths, and thus tenants could not cook inside them even if they wanted to--an *insula* was a place to sleep, and little more. The urban *plebs*, therefore, lived generally outside their tenements, and survived on food cooked outside. At communal ovens and by paying for the services of bakers the urban *plebs* could turn the wheat they bought or were distributed into bread, although Purcell has shown that most urban dwellers survived mainly on [a sort of porridge rather than bread, which was too expensive for most of the population to make](_URL_2_). The \"average\" urban dweller, living in a tiny *insula* without any landholdings of his own and likely with no steady income, would not have been able to conceive of a situation, save owning his own *domus*, in which he might be able to cook his own food.\n\nOn the other side, those who owned their own property were, in the city at least, almost invariably fabulously wealthy. Property was at a premium in the city, and urban *domus* were exclusively the possessions of the *equites* (really just wealthy plebeians, although under the Principate they became a distinct *ordo*) and the senatorial class. While we hear of people like Caesar and Sulla, who began their lives relatively impoverished, these individuals were aristocrats with hundreds, if not thousands, of clients and dependents, and estates throughout Italy. They may have had a lack of ready cash (land is not so easy to liquidize) but the sum of their assets would have dwarfed the means of the urban *plebs*. For people who could own property in the city, invariably their own *domus*, often quite extravagant, there was always food available inside. These wealthy individuals had, at the very least, a few slaves and hired workers to run the house, and in particular the kitchens--the *equites* and senatorial class did not cook their own food, and they did not worry much about their own provisions, leaving it to someone else. Owning property in the city was a considerable investment, one that continued to eat up money in the form of maintenance, provisions, and wages for workers, and it's unrealistic to imagine anyone but the very wealthy owning their own urban homes. \n\nAll this aside, what options *did* exist for \"street food,\" so to speak, in the city? For the urban *plebs* really everything was street food, in that all of their meals were prepared out-of-doors, often by someone else. For somewhat better meals than a bowl of emmer *puls* (basically warm mush) or bread there were *thermopolia* and *popinae* available. The former are basically sit-down establishments with a decent amount of room and, usually, long bars on which were placed cauldrons filled with whatever the owner felt like filling them with. They're all over Pompeii, a quick google search should give lots of examples of really rather nice ones, with stucco'd countertops and even frescoes. The latter were sort of little food stands, usually permanent rather than something like food carts, that sold pastries and other items that could be eaten on the go. Both are rather well-attested in literature as being places that educated people like Juvenal and Martial might go, and from what little evidence we have it doesn't seem likely that the urban *plebs* spent a lot of time in such places, whose prices were probably unreasonable for most day-workers, whose lives were more or less hand-to-mouth. As Purcell notes, for most of the urban population the supplements to their diet of wheat, either as *puls* or bread, were mainly nuts, chickpeas, and fruit (dried or fresh), which could be picked up relatively easily at markets while passing through on the search for work whenever laborers had a little extra money left over. "
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jws3t | How does humidity affect how sound travels? | askscience | http://www.reddit.com/r/askscience/comments/jws3t/how_does_humidity_affect_how_sound_travels/ | {
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"It only has a very slight effect. At 20 ºC sound travels at 343.4 m/s @ 0% relative humidity and 344.6 m/s @ 100% relative humidity. ",
"I believe it has more to due with the attenuation of the sound wave, rather than the speed. [Have a look at this link from NPL in the UK](_URL_0_). A researcher in my group who does experimental acoustics has told me he has to make corrections during the summer and winter months based off a hygrometer reading. It seems to be entirely dependent on the wave frequency and humidity and the trends are not the same for every frequency.",
"It can have a huge effect on sound attenuation vs. frequency. I was doing some research for an art project and found the following information. [Information on speed and attenuation of sound.](_URL_0_)\n\nEdit: Just noticed that RocketSurgeon85 linked to the same page. Hello, fellow AeroE!",
"It only has a very slight effect. At 20 ºC sound travels at 343.4 m/s @ 0% relative humidity and 344.6 m/s @ 100% relative humidity. ",
"I believe it has more to due with the attenuation of the sound wave, rather than the speed. [Have a look at this link from NPL in the UK](_URL_0_). A researcher in my group who does experimental acoustics has told me he has to make corrections during the summer and winter months based off a hygrometer reading. It seems to be entirely dependent on the wave frequency and humidity and the trends are not the same for every frequency.",
"It can have a huge effect on sound attenuation vs. frequency. I was doing some research for an art project and found the following information. [Information on speed and attenuation of sound.](_URL_0_)\n\nEdit: Just noticed that RocketSurgeon85 linked to the same page. Hello, fellow AeroE!"
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1rvfuz | What are the main differences of quantum mechanics from 1932 to today? | Doing a research paper on Werner Heisenberg and am curious as to what ideas from his time have changed alot. | askscience | http://www.reddit.com/r/askscience/comments/1rvfuz/what_are_the_main_differences_of_quantum/ | {
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"This is sort of way too vast to answer. The one aspect I would focus on is the Einstein-Podolski-Rosen paradox (regarding quantum entanglement and faster than light communication), and Bell's theorem which put this thought experiment into a realistically testable form. There have been many experiments demonstrating the EPR effect and testing Bell's theorem.",
"One pretty interesting difference is that we've made some progress in terms of understanding why we see only probabilistic results when we do experiments. I'm not saying we completely understand it, because we don't, but we can at least show that classical probability distributions show up in a purely \"Schrodinger's equation\" (or Heisenberg's equation) formulation of quantum mechanics.",
"Well one interesting thing you could talk about is the \"merging\" of Heisenberg's ideas with the ideas of Schroedinger and others. This was done by (mostly) von Neumann and is contained in the Stone-von Neumann theorem. This isn't exactly post 1932, and it's very technical, but it is also extremely important.",
"The biggest difference is the shift from Heisenberg/Schrodinger/Dirac mechanics to full fledged quantum field theories. Whereas the original mechanics would describe something such as the probability of a photon being at a certain location, QFT describes the probability that a virtual photon will be created or destroyed. Another important change is the use of renormalization. Early attempts at quantum mechanics weren't useful past describing the most simple experiments, but the mathematical tools of quantum electrodynamics allowed it to make extremely precise numerical predictions. After this shift, physicists began developing theories of the fundamental forces described in the language of quantum mechanics. After unifying special relativity and quantum field theory with QED, the electromagnetic force was unified with the weak nuclear force, and the electroweak force was unified with the theory of the strong force (quantum chromodynamics) to build the standard model. Whereas the old quantum mechanics focused on describing experimental anomalies, much of quantum mechanics now focuses on describing elementary particles and mediating forces."
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718217 | what is the science behind a shower being too warm one day and on another the ideal temperature is near scalding? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/718217/eli5_what_is_the_science_behind_a_shower_being/ | {
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"Part of the plumbing for a house is in the Attic. The Attic temperature changes the temperature of the water in the pipes that are in the Attic. After some time on the temperature of the water generally stabilizes, as it will not be heated or cooled by the attic. In addition the type of piping can change the way heat is released into the pipes. "
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5c5pdp | what function does tongue-rolling serve in order for some to have the gene and others not? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5c5pdp/eli5_what_function_does_tonguerolling_serve_in/ | {
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"If you roll your tongue, then you're automatically superior to others and must immediately ask anyone you come across, \"Can you roll your tongue, dude?\". Should they fail to do so, you give them a look of disapproval and slowly back off. When meeting them again, remember that you're better than them in every way and that you should remind them as such whenever you can.\n\nOh wait. This is ELI5, not AskReddit.\n\nTongue-rolling gives you pretty much no advantage nowadays, and it's a pretty random gene. And since mating in humans nowadays isn't based on the tongue-rolling gene, you don't have better or worse chances of mating and having kids that might carry the gene. In the end, it's kind of like hair color- different from person to person, but not having any really important purpose.",
"There is not a lot of supporting evidence that says tongue rolling is genetic. The common wisdom is that tongue rolling is dominant and non rolling is recessive. But two parents who cannot roll their tongue can have a child that does. Also in Twin studies identical twins are not more likely to share the trait than fraternal twins."
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108434 | Can empirically derived equations be found theoretically? | For example, I couldn't sleep last night so I pulled out a dusty old fluid mechanics textbook. There was a quick section on check valves, and determining the fluid velocity required to open the valve - and there was a note that the corresponding velocity equation was empirical, which leads to my question. And vice-versa? | askscience | http://www.reddit.com/r/askscience/comments/108434/can_empirically_derived_equations_be_found/ | {
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"If I understand the question, you are asking if engineering can be derived from physics. In principle yes, but deriving the connection between fundamental interactions and empirical phenomena might be extremely tedious or computationally prohibitive. Still it can be done, and one major example is materials science. An enormous amount of progress has been made toward obtaining large scale material properties such as resistivity, thermal conductivity, Young's modulus, etc. from the basic interactions of atoms. \n\nUltimately of course, the fundamental physics formulas are taken as fact *because* they have been verified empirically.",
"The hallmark of a successful theory is that it predicts the correct form of empirically derived laws.",
"Yes, if a theoretical framework begins with the correct premises and rules, it is possible to derive equations theoretically which will end up matching empirical observations of a system with the same starting states and natural laws. However, figuring out the correct starting conditions, and deriving pragmatically useful equations, is usually more difficult than just observing the system and deducing equations empirically.",
"It certainly has been done. One of my favorite examples of an empirically derived equation that was proven to be true from first principles is the good ol' ideal gas law PV=NRT. \n\n[Wikipedia Derivation](_URL_0_)\n\nIn most cases, the use of empirically determined equations (e.g. gas solubilities, equation of state for seawater) is simply a matter of necessity because we lack a complete understanding of the underlying dynamics. So to answer, your question, yes it is possible to derive what was thought to be an empirical formula from first principles; sometimes it's just really really hard :) ",
"Interesting related note: Bernoulli's equation for incompressible fluids can be derived a number of ways, but obviously it's properly p=(rho\\*u^2 )/2. Before Bernoulli and Euler, though, experiments had pretty much come up with the same equation, except that the entire thing was multiplied by a constant that ranged from something like 0.8 to 4, depending on who you asked. The reason for this constant was basically just experimental error; its real value is 1. So it's kind of *an* answer to your question: this was an equation which had more or less been confirmed experimentally, and only later was it actually derived mathematically/theoretically. \n\n(Anyone feel free to correct anything I've gotten wrong. I'm loosely remembering this from an aerodynamics textbook that I no longer own, and couldn't find anything on Wikipedia confirming the details)"
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19448z | What did the American police uniform look like in the 1840's? | edit: sorry, I didn't know they looked different all around the country and state and such. I'm asking for police uniforms the New York City area. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/19448z/what_did_the_american_police_uniform_look_like_in/ | {
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"Which city? We know the 1850s for New York ([see here, from Wikipedia](_URL_0_) ) but I suspect each city had its own particular format. US police forces of the era seemed to dress in blues and other darker colors that wouldn't show dirt or injury readily, although whether that was new to that period I do not know.",
"Differs not only from state to state but from county to county, parish to parish, and city to city."
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1qfiwr | Does high cholesterol really cause heart disease? | In Australia, the ABC recently ran an episode on the program The Catalyst, which suggested that high cholesterol does not cause heart disease and most people are wasting their time taking cholesterol-reducing drugs called statins. An article on this episode can be found [here](_URL_1_).
The Program "Media Watch", which targets bad reporting (and is also on the ABC) challenged the 'alternative views' that were presented in The Catalyst (a transcript of this can be found [here](_URL_0_)).
Both sides claim to have "science" on their side, so I thought I'd ask the experts.
Does high cholesterol cause heart disease? | askscience | http://www.reddit.com/r/askscience/comments/1qfiwr/does_high_cholesterol_really_cause_heart_disease/ | {
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"Yes. High cholesterol leads to the deposition of fatty streaks, known as atheromas, in the arteries. The cholesterol in these atheromas is phagocytosed (eaten) by macrophages which then become foam cells. The macrophages are incapable of breaking down cholesterol and they end up releasing inflammatory cytokines (messenger molecules). These inflammatory cytokines recruit more macrophages which phagocytize more cholesterol and the plaque grows. I should mention that this process is happening inside the wall of the artery which is 3 layers thick, the tunica intima, media and adventitia. The cytokines released by the macrophages also recruit fibroblasts to the tunica intima where they lay down collagen fibers. This creates a fibrous cap over the atheroma and also hardens the artery. If the cap is damaged by high blood pressure the collagen will be exposed and a thrombus(blood clot) will form. If the thrombus is large enough it will occlude the artery there or it could embolize (break off and enter circulation) and cause an occlusion somewhere else. \n_URL_0_ The image there is one of the better ones I could find.",
"**Yes.**\n\nCholesterol is pivotal in causing heart disease, it builds up in the walls of arteries that supply the heart causing narrowing and can potentially rupture, blocking the vessel and causing a heart attack.\n\nCholesterol floats around in the blood in little balls called HDL and LDL. HDL is \"good\" it can pick up cholesterol from artery walls. You want it to be high. LDL is \"bad\" it deposits cholesterol. Statins alter cholesterol metabolism in the liver and can lower LDL and raise HDL. \n\nIn medicine the best evidence is real world experimental data. A drug might work in theory but that doesn't matter if it can't be shown to work in real patients. The gold standard test is called a randomised control trial. \n\nA [study](_URL_0_) in Scotland took over 6000 middle aged men with high LDL levels and no history of heart disease. They gave half of them statins and half a placebo pill. Both groups were given dietary advice and monitored. They found the group that were given statins had a reduction in rates of heart attack by 31%. That means if you had a 10% chance of having a heart attack your risk is reduced to about 7%. Not perfect but on the large scale that could equate to thousands of lives. \n\nThe important concept here is something called relative risk. If you're a healthy 25 year old you wouldn't need to take statins because your risk is already extremely low. They would have most benefit in someone who is high risk, specifically with high cholesterol/LDL. Other aspects of prevention are still important, e.g. managing blood pressure, not smoking and exercising regularly. \n\n*Media Watch* got this one right: Cholesterol causes heart disease, statins can prevent heart attacks and death. That is the medical and scientific consensus, the men on Catalyst were a minority that share a fringe theory and the real experts were not given sufficient input. "
]
} | [] | [
"http://www.abc.net.au/mediawatch/transcripts/s3888657.htm",
"http://www.abc.net.au/news/2013-10-28/professor-says-abc-catalyst-episode-could-result-in-deaths/5050866"
] | [
[
"http://emedicine.medscape.com/article/153647-overview#aw2aab6b2b2"
],
[
"http://www.nejm.org/doi/full/10.1056/NEJM199511163332001"
]
] | |
4zhtv7 | what happens when someone sends you a text message but your phone is switched off? where 'is' the message until it reaches your phone? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4zhtv7/eli5_what_happens_when_someone_sends_you_a_text/ | {
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"It is sent from the sender's phone to their phone carrier. In my case Vodafone but it could be AT & T, BT, Orange - whatever.\n\nMuch like an e-mail, it is routed to the correct telephone number (it may as well be an IP address for this explanation). The phone sends a signal back to the provider saying it has received the message. If no such reply is found, the provider keeps the text message on a server somewhere and next time the phone is turned on and sends it's handshake to the provider (remember it takes 2-10 seconds sometimes when you first turn it on to get signal), the provider checks to see a list of any messages, voicemails etc that need alerting and then it sends out the push notification. the handset receives it, and sends back the reply stating it's received it.\n\nThe text message is then on the phone and depending on your provider, kept on record for hours, days, weeks, years or forever on their end.\n\nDuring this process, they may send it out every hour or every day just on the off-chance. This is why sometimes you don't get a text for a day but then get the same one 3 times in a row. The system is out of sync.",
"Oh finally something I can actually answer. \n\nCore network engineer here. There is a server in provider network called IP-SM-GW or IP short message gateway. It stores the message for an arbitrary amount of time (different per provider) and sends it to the user once he registers with the network. Now this applies to IP networks (most providers are switching to them now) but in the older infrastructure there was a different node responsible for the same function called SMSC or SMS center. Basically the same thing just with different transport layer.",
"So what happens when someone sends you a bunch of texts, but you don't receive them for a couple days?",
"My phone was turned off for two weeks while I was out of the country, and when I got back to the states I spoke to a few friends and it turned out I only got like a quarter of the texts. Any explanation as to why they didn't all go through? Is it because my phone was off for so long that Verizon would have deleted the earliest ones and I only got the more recent texts?",
"I have the answer to this.\n\nAre you ready for the answer to this?\n\nOkay, you said you're ready for the answer to this.\n\nI'm sending the answer to this.\n\nTransfer Control Protocol is the answer to this.\n\nDid you recieve the answer to this?\n\nYou didn't respond. Limit of attempts reached.\n\nI'll try to send the answer again in the designated time.",
"The cellular network tracks whether your phone is connected to the network or not. This is called your device's registration. When your phone is turned off the network will consider your de-registered from the network. If a text message destined for your phone is received by the network while your phone is de-registered then the network will store that text message on a server until you turn your device back on and register once again.",
"It's pretty similar to what happens if someone mails you a package but you aren't home to receive it. The mailman will try again until he or she is able to deliver the package for you and you sign for it.\n\nIn the case of a text message, if your phone is off, it will simply sit on the carriers servers (post office) until you turn your phone back on. Once your phone then connects to the carrier, it will know that it is on (you are home) and deliver the message to your phone. Your phone will then send a response saying it has received the message (signing for the package) so that it won't try to send it to your phone again.\n\nSee the other posts for more detailed, ELI25 answers.",
"I work in cellular engineering! I can answer this!\n\nWhen a text message is sent to you their phone sends their carrier a bit of data asking for a connection. The data is flagged as a text message so the connection is made between their phone and the switch at a central switch office, using a router that connects the cell tower to the router at the switch office.\n\nThen they send that information to a text messaging server called an SMS Center. \n\nThe SMSC looks to see where the message _URL_0_ be sent. Let's say you don't have the same carrier. In that case it goes \"not us!\" And sends it via a special trunk (big fiber optic that carries a lot of long-distance traffic) to a company that offers inter-carrier messaging. In the US almost all carriers use Synniverse, Verizon, Sprint and ATT do I know.\n\nSynniverse (or your area's inter-carrier messaging vendor) has a huge chart of what companies own what number that they use to figure out who to send the traffic to. They split the traffic up so one message server doesn't get overwhelmed. A large carrier might have five or more SMSC all over the country at their regional connectivity data centers (RCCs).\n\nThe inter-carrier messaging provider also offers such features as spam filtering (by keyword and by source) and accounting support (carriers pay each other to terminate messages, but rather than do it for every message they add up every message sent and received and pay the difference between the two if they sent more or get a check if they received more than they sent).\n\nOnce it is at the SMSC on your side they send a message to the radio controller called a page saying \"find this phone\". It looks in a table called the Visitor Location Register, or VLR to see where you are. \n\nIf no VLR exists because you aren't connected to any network, it leaves a message in your Home Location Register saying \"hey when you make a visitor registry for this guy, let me know.\". That way when you connect the system makes a copy of your HLR to create a VLR, and when it does it sends the SMSC a message to retrieve your waiting messages and deliver them.\n\n\nAnd that is exactly, in detail, how it works. On a CDMA network anyway. GSM is very.much the same but names are different.",
"Want a true ELI5?\n\n**Short Version**\n\nYour friend's phone sends it to the carrier message centers. The centers store it on their computers. When your phone turns on, it asks for the messages from the center. Once delivered, the center deletes the message off their computers.\n\n\n\n**Long Version**\n\nYour friend texts you a text message. His phone sends it to his carrier's message center which then relays it to your carrier's message center through their private network. A message center stores all the messages on their server computers, running 24/7. The carrier then notifies your phone that there's an incoming message. If your phone is off, nothing can be done for now.\n\nWhen your phone is turned back on, it will ask the carrier for the list of incoming messages. The carrier gets them from their server computers and delivers to your phone. Your phone communicates digitally with the carrier through a set of GSM/CDMA network standards, first written way before the internet. Once your phone got the messages, it lets the carrier message center knows to delete them off their computers (although they will just keep it stored privately for as long as they want and you will never know).",
"I had a SIM card for the US and I took it out when I went home to Canada for a week. I used my Canadian SIM (same iPhone). When I returned to US, people said they sent me messages on the number of the US SIM that I took out, but I never received them. The latest messages I received were from two-three days before I returned to US. I'm curious, where did those other messages go? (my friends showed me the texts they sent me that I didn't receive). Is there something with the fact that the SIM was not in a phone? According to this thread they would be held until I reinserted the SIM... "
]
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[],
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2vjpa1 | what is happening when i'm pumping gas and stops every 1/4 gallon like my tank is full? | Sometimes when I'm pumping gas it'll kick off every 10 seconds ink unless I'm giving it barely any pressure. It's pretty annoying and can make a 10 gallon full up take 5 minutes and all my patience not to pull it out of my car and spray it around like the scene from Zoolander. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2vjpa1/eli5_what_is_happening_when_im_pumping_gas_and/ | {
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"text": [
"Could be a kink in either the inlet pipe or the breather tube inside the inlet pipe. ",
"What is most likely happening is the gas isn't going into the tank fast enough. This causes the gas to back up a bit in the nozzle and trip the valve that shuts off the flow when your tank is actually full. Try adjusting how far in the nozzle is in your tank. I find having the nozzle in deeper usually helps.",
"Not an explanation, but a solution; I have this happen on my wife's car. Friend of mine told me to twist the nozzle so it's upside down when pumping, which seems to have fixed it for me. "
]
} | [] | [] | [
[],
[],
[]
] | |
ezlg0 | Do you think my generation will live longer than the current live expectancy? (I'm 18yo) | askscience | http://www.reddit.com/r/askscience/comments/ezlg0/do_you_think_my_generation_will_live_longer_than/ | {
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"text": [
"If you can afford to, yes. Life expectancy is closely tied to prosperity.",
"I remember reading somewhere that life expectancy is on a decline for the first time in a while.",
"I had an Economics of Healthcare class three years ago. According to that, life expectancy is expected to decrease.\n\nHowever, I'd say that you have the ability to exceed the expected lifespan of the previous generation, due to advances in nutritional research and medicine. However, most people in our generation will not take advantage of these and will die young.",
"That depends greatly on whether we hit the singularity.",
"So, it's important that if we're going to talk about living a long time that we don't talk about life extension. That's a weird sort of loaded term that brings up thoughts of being stuck to a machine for thousands of years while civilizations goes on without you. \n\nThere's a discussion about compression of morbidity, that comes with calorie restriction, but who wants that. We want the medicine! What we want to talk about is called **healthspan extension**. There are several organizations working to making this happen: \n\n_URL_2_ -- researching the ways in which the body becomes 'old' and possible avenues to interrupt that pathway. SENSF has part of its organization devoted to training and funding the next generation of aging researchers (if there are any redditors who are looking to get involved with the organization, drop me a line). \n\n_URL_0_ -- putting up money to award to groups that actually come up with life extension therapy (think x-prize)\n\nThere are a number of organizations that work to promote discussion and thought on the topic of life extension. You can start looking at _URL_1_ for discussions from Ray Kurzweil and Aubrey DeGrey. ",
"There are some that believe, through transhumanism, that the first person to live to a thousand is alive today."
]
} | [] | [] | [
[],
[],
[],
[],
[
"http://www.mFoundation.org",
"TED.com",
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f1h51v | Did the French Revolutionary Government ever propose attempting to get Acadia and Canada back from Britain after the 7 Years War or did they just accept it as the past? | I know the French Monarchy didn’t care too much for either Acadia or Canada but would the more radical voices in the Revolution had seen the lack of care as a betrayal to the French people in North America? Obviously this would’ve been impossible though as any rational mind would know the Royal Navy would never allow a large enough French Force that could threaten their position in North America pass the Atlantic; simply asking because the French Revolution isn’t known for producing very many rational minds. | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/f1h51v/did_the_french_revolutionary_government_ever/ | {
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"fhaklhl"
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"text": [
"This is more like two questions (New France during the British conquest, and Canada around the time of the French Revolution, but they're somewhat related.)\n\nDuring the Seven Years War, royalist France -- it was still a monarchy then -- absolutely wanted to retain New France, up until the conquest of Quebec in 1759. The war over North America began before the hostilities in Europe. The French army was still in the field and were awaiting reinforcement and supplies to come up the St. Lawrence when they fell back to Montreal. In the Battle of Quiberon Bay, also in 1759, the British navy defeated the French navy -- ending any hope of relief for New France. The French cause in Canada was lost in the spring of 1760, when the French saw British ships sail up the St. Lawrence. In the negotiations for peace, France could either retain Canada and its fur trade, while giving up Guadaloupe and its more profitable sugar trade, or cede New France and keep Guadaloupe. France chose sugar over fur and gave Britain its North American empire.\n\nBy the time of the French Revolution in 1789, the Canadas had already been invaded a few years earlier by revolutionaries of another stripe: Americans. The French Canadian population had lived under British rule in peace for some 15 years when the US War of Independence began, and with very generous terms under the Quebec Act: they kept their religion, language and property rights. They weren't fond of their British masters, but they trusted their virulently anti-Catholic American neighbours even less. The failed US invasion of Quebec in 1775 had given the Canadas a taste of republican sentiments, which would sour them on the French Revolution's political and social excesses. The beheading of Louis XVI turned any lingering sympathies in Quebec against the revolution.\n\nFrance of this era was now a republic intent on expanding its European interests, while French Canadians in Canada had been British subjects living in peace for about 30 years. They had little desire to welcome such revolutionary chaos into their lives in British North America. The France of Robespierre was too distracted by its various wars and failed royalist uprisings at home to give much thought for their Quebec cousins -- and the dominance of the British navy ensured that this remained so."
]
} | [] | [] | [
[]
] | |
22xp68 | what is the deal with "mermaids the new evidence show". | My co-worker thinks mermaids are a real thing, I don't. Can someone explain whats going on? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/22xp68/eli5_what_is_the_deal_with_mermaids_the_new/ | {
"a_id": [
"cgrejup",
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"text": [
"It's a TV show meant to get ratings and thus advertising revenue. Mermaids aren't real, and I strongly doubt that anyone involved in making that show seriously believes otherwise. ",
"The documentaries are entirely fake and intended as entertainment. All of the \"scientists\" in them are actors. Sadly, they don't make this very clear, and hence gullible people believe it's real.\n\n_URL_0_"
]
} | [] | [] | [
[],
[
"http://en.wikipedia.org/wiki/Mermaids:_The_Body_Found"
]
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4ts9nh | why do clones of app store games take almost no time to appear? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4ts9nh/eli5_why_do_clones_of_app_store_games_take_almost/ | {
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"text": [
"App store games can be made in about a month or three if you're dedicated, and when you're making a game based on another game that was written for Android or Apple's OS, it's not *terribly* difficult to pull apart the code and study it's guts. \n\n\n\nThough you wouldn't want to plagiarize the code, it's not difficult to adjust it just enough that it's different without really being *different*. \n\n\n\n > If it's so easy to make these apps how come none of them come from NA? \n\n\n\nCopyright protection and other legal gymnastic challenges. China- in blunt terms- has virtually no legal protections afforded to international companies, while the US will bend over backwards to protect them if it doesn't go against national interests. ",
"Copying apps/products/websites is ridiculously easy. You don't need to spend any time on creativity or mechanics, just literally copying. \n\n**First up: concept.** *Building* a new game/app takes a tremendous amount of creativity/insight/etc. But imitating? Not much.\n\n**Now for the mechanics.** Figuring out all the logistics that make a game fun/playable is very hard. But once you have a mechanic, tweaking is again very easy. Once you know you have \"builders\" as a game dynamic, you can easily adjust. Flying builders! Digging builders! 4-armed builders! Wows!\n\n**Finally the work.** Using services like oDesk, there are seemingly unlimited coders out there ready to copy & paste your favorite game/site/etc for a pittance. Love that word.\n\nThink about food, for example. If I were to ask you to _invent_ a dish, how would you go about it? Think of the testing, tweaks, etc to get it right (and thats after you pick your basic genre/etc). Now if I were to say \"see this recipe for quiche? use it, but then at the very end, add more pepper\" it'd be pretty easy to follow. And once you've done that, you could, independent of the original recipe, begin to adjust the components, presentation style, etc. Until eventually you have your very own quiche, that sure resembles the first one, but you \"invented it\" in no time at all.\n\nI had a startup a few years back called Legacy Locker (online will service, got acquired in '13). We raised some funding, hired a local programmer and designer we could work with to figure out our MVP, launch, etc. A few months later I saw on oDesk a call to create a clone, with a budget of under $5K. They basically asked to build the exact same thing, but swap out the graphics... I don't know what happened to it, but they had numerous bids.\n\nBottom line: ideas aren't valuable, but implementations are, and copying them is cheap.\n\n"
]
} | [] | [] | [
[],
[]
] | ||
3s4c22 | why do dogs choose a favorite person in the family? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3s4c22/eli5_why_do_dogs_choose_a_favorite_person_in_the/ | {
"a_id": [
"cwtz7bv"
],
"score": [
6
],
"text": [
"The alpha dog is a myth. Dog behaviour is far more complex than we have previously known and still being studied. \n_URL_0_"
]
} | [] | [] | [
[
"http://io9.com/why-everything-you-know-about-wolf-packs-is-wrong-502754629"
]
] | |
1v5n5k | Is there any material that is accessible to humans (either natural or artificial) that can withstand the temperature of our sun? | And if so, how have/can we used/use it to our benefit? | askscience | http://www.reddit.com/r/askscience/comments/1v5n5k/is_there_any_material_that_is_accessible_to/ | {
"a_id": [
"cep3ilg",
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"text": [
"If you think about heating a material from 0 up to the temperature of the sun, something must remain, though it could be a gas! Rhenium is a liquid at 5778 K, and I wouldn't be surprised if there were some metal oxides still solid at that temperature. Most of the oxides have useless mechanical properties though.",
"Short answer: No.\n\nLong answer: We currently don't know any materials able to withstand the temperatures of our sun, but the prospects of finding such a material depend on where on or in the sun. \n\nThe surface of the sun has a temperature of roughly 5800K. The material with the currently known highest melting point, [tantalum hafnium carbide](_URL_0_), has a melting point of 4488K. So while there is no material currently known to withstand 5800K as a solid it's at least close enough that it is conceivable that such a matrial could exist and could be found with some research effort.\n\nIf you mean deeper inside the sun, then definitely not. Temperatures there are in the millions of kelvins. Everything will turn to a plasma at these temperatures."
]
} | [] | [] | [
[],
[
"http://en.wikipedia.org/wiki/Tantalum_hafnium_carbide"
]
] | |
2tiudn | what's the meaning of "ayyy" and "ayyy lmao": what is the difference between them and what's the origination? | the title says it all; the question might be better for r\outoftheloop. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2tiudn/eli5_whats_the_meaning_of_ayyy_and_ayyy_lmao_what/ | {
"a_id": [
"cnzgg9f"
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"text": [
"It's just a picture of an alien with the words \"ayy lmao\" on it, for some reason it went viral-ish, I think mostly on tumblr. And every time you see the picture or you see someone else say \"ayy lmao,\" you're supposed to respond with, you guessed it, \"ayy lmao.\""
]
} | [] | [] | [
[]
] | |
6zg2ca | can you technically lucid dream anything and experience anything? if so, can you really conjure up the unimaginable? or experience something you've never experienced before? would it ever be accurate? for instance experience scuba diving in dream, would it be as accurate as in real life? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6zg2ca/can_you_technically_lucid_dream_anything_and/ | {
"a_id": [
"dmuxlef"
],
"score": [
3
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"text": [
"Anything you haven't experienced before would just be a guess based on combinations of what you *have* experienced before.\n\nIt *could* be close to accurate. But that would be difficult to know without then immediately doing that thing before the memory of the dream fades, and even then your memories are constantly being updated, so you might automatically update your memory of the dream to match the new memory of scuba diving because your mind associates both with \"scuba diving\". "
]
} | [] | [] | [
[]
] | ||
6hadw5 | when we feel wind hitting us, what are we actually feeling? what is actually hitting us? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6hadw5/eli5_when_we_feel_wind_hitting_us_what_are_we/ | {
"a_id": [
"diwrc3q",
"diwrda1",
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"score": [
2,
9,
2
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"text": [
"Wind is when air from high pressure areas is moving towards area with lower air pressure. If the air pressure in the troposphere was universal throughout there'd be no wind.",
"From a conscious view...that's complex. From a wind view, molecules of air. Same as anything rubbing against your skin.",
"Generally speaking, you feel the wind mostly through the movement of fine hairs on the body, or through cooling or change of pressure upon the skin.\n\nAir is mostly nitrogen gas, but we can't really feel it too well directly with our skin, otherwise we would feel sound waves(which is vibrating air).\n\nTry looking up *schlieren photography* to get a better understanding about moving air."
]
} | [] | [] | [
[],
[],
[]
] |
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