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6snjgy
|
how do headphones create sound by connecting a metal post into a metal housing and sending information through a wire into speakers?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6snjgy/eli5_how_do_headphones_create_sound_by_connecting/
|
{
"a_id": [
"dle31ob",
"dle5gly"
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4,
2
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"text": [
"They don't send \"information\", they send an analog electrical signal. That signal is run through a coil to produce a magnetic field. A small permanent magnet reacts to the field, moving a small speaker cone back and forth to produce sound waves that your ear can detect.",
"Sound, what our ears \"hear\" is actually vibrations in the air around us. The air moves in waves, compressing and decompressing radiating outward from the source of the noise. So remember, the sound is just another word for compression waves in the air. \n\nTo make sound from a speaker, magnets move a bladder back and forth. Basically, the magnets turn on and off causing the \"cone\" in the speaker to move inward and outward. This movement compresses air and creates sound. It's the same principle in headphones as it is on the biggest speakers at the loudest concerts, it's just a matter of scale. \n\nSo speakers don't really get \"information\" they take an electrical signal and use it to turn the magnet on or off, that's it. The signal tells the speakers to VERY quickly turn the magnet on and off. It does this by supplying power over that tiny wire. So there's really no \"information\" transmitted as much as power is supplied or not, and the speakers turn that into sound. "
]
}
|
[] |
[] |
[
[],
[]
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||
5qlea5
|
why do so many people equate abortion with murder when an unwanted baby is often subject to a lifetime of pain and depression due to their parent's inability to care for the child?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5qlea5/eli5_why_do_so_many_people_equate_abortion_with/
|
{
"a_id": [
"dd06dgd"
],
"score": [
2
],
"text": [
"Because apparently a life full of suffering and pain that likely ends tragically, is better than not being alive at all."
]
}
|
[] |
[] |
[
[]
] |
||
9av5ku
|
if dust in houses is mostly caused by dead human skin cells then why are old abandoned houses always so dusty?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9av5ku/eli5_if_dust_in_houses_is_mostly_caused_by_dead/
|
{
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"text": [
"There's no-one there to clean them. Dust, which comes from many sources of which dead skin cells are only one, builds up over time. Most people do at least a little cleaning of their homes.",
"You've been misinformed. Dust is not made up of mainly human skin. It's just that every sample of dust you take inside a home will always contain some human skin.\n\n \n\n\nDust isade of various small particles. Like fibers from clothing or plants, pollen aggregates, etc. And there's always some dust in the air as can be seen when a ray of light shining through a room is observed from the side.\n\nSince dust particles are very light they can ride on air currents but since their density is greater than air they will always settle on surfaces given enough time. Since abandoned houses usually have large undisturbed volumes of air all that dust will slowly settle on surfaces. (As long as it's not wet or there are huge drafts inside, this will cause more general \"dirt\" to accumulate).\n\n \n\n\n \n",
"Dust is always in the air moving around and it settles when undisturbed. The difference between an abandoned house and an occupied one is that, there's no disturbance and dust settles on surfaces so that they're more visible.",
"The majority of dust is actually tiny particles of dirt which tend to find their way inside a house because houses are not airtight. The particles are small enough to become airbourn when there is any amount of wind outside but they are still heavier than the air and will later fall once inside a house."
]
}
|
[] |
[] |
[
[],
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||
xp6sy
|
I wonder what historians think of Niall Ferguson.
|
I read his book, The Ascent of Money, and I liked it. I've tried reading more of his work, but it's awfully political at parts. Which makes me skeptical. I googled opinions about him, I read his research on the Rothchilds was original and excellent but that his work went a bit downhill from there. I wonder what actual historians think of him.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/xp6sy/i_wonder_what_historians_think_of_niall_ferguson/
|
{
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"text": [
"I can only speak about his work on empire - which most historians dismiss as too one-sided and just bad. To put it bluntly, he gives a very distorted view of the British Empire, implying that, on the whole, it was an example of a \"benevolent\" imperial power who brought progress and modernity to the colonies in contrast to those big, bad, icky empires of France, Germany, and Japan. That, faced with the alternative, the British Empire was a positive historical phenomenon for the colonial world. Of course, specialists on the British empire (well, new generation) have the opposite view. They point to the harrowing violence the British colonial police inflicted in Kenya during the 1950s (concentration camps, systematic torture), suppression of Irish nationalism in the 1920s via the vicious Black and Tans, civil war and mass killings triggered by the sudden partition of British India, using air raids to terrorize villagers into submission in post-WWI Iraq, etc. etc. Empire was (is?) much more complicated than just constant victimization, of course. But at the root of all the real \"progress\" or change introduced into the colonies was exploitation and violence.\n\nOn the other hand, he's very charming and persuasive in person (I've heard him speak in public). I think his early work on finance is respected more but I haven't read it. He's published a lot, good at generating public interest in otherwise boring topics, which is probably why he's at Harvard. But, no, I don't expect him being elected president of the American Historical Association anytime soon.",
"Never placed much faith in his argument that a post world war one German dominated Europe would have been best. I had the opportunity to talk to him once after he gave a speech that US troops levels in Iraq needed to be drastically increased based on the number of British soldiers needed in Iraq in the early 20th century and didn't place much faith in that argument either ( for the record I was right). \n\nI think he is a talented historian regardless of his views, and his works have led to new discussions on historical topics.\n\nedit- I enjoyed his arguments in Colossus well worth reading",
"Nice try, Niall Furguson.\n\nBut seriously I've only read *The pity of War* and to be honest, its criticised for good reasons."
]
}
|
[] |
[] |
[
[],
[],
[]
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|
12zccz
|
why can't i become the president of the united states (i was born in canada)?
|
Why is it that because I am not a natural born citizen of the United States, I can not become the President (or vice-President), but I can be appointed to the cabinet, or become a senator, or a governor, or even the General of the Army? I doesn't make much sense to me.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/12zccz/why_cant_i_become_the_president_of_the_united/
|
{
"a_id": [
"c6zelco",
"c6zeq09"
],
"score": [
3,
3
],
"text": [
"Its the rules\n\n**US Constitution, Article II, Section 1**\n\nNo person except a natural born citizen, or a citizen of the United States, at the time of the adoption of this Constitution, shall be eligible to the office of President; neither shall any person be eligible to that office who shall not have attained to the age of thirty-five years, and been fourteen years a resident within the United States.",
"The founders were nervous that a foreign power would attempt to control the country by getting one of their own elected president. Hamilton wrote in the Federalist Papers:\n\n > Nothing was more to be desired than that every practicable obstacle should be opposed to cabal, intrigue, and corruption. These most deadly adversaries of republican government might naturally have been expected to make their approaches from more than one querter, but chiefly from the desire in foreign powers to gain an improper ascendant in our councils. How could they better gratify this, than by raising a creature of their own to the chief magistracy of the Union?\n\nAlso, if we let, say, Arnold Schwarzenegger become president, and some Austrian rose to become a belligerent European dictator (unrealistic, I know), there'd be concern that he wouldn't necessarily act in the best interests of the United States."
]
}
|
[] |
[] |
[
[],
[]
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xtlnz
|
what does curiosity do besides taking pictures of mars?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/xtlnz/what_does_curiosity_do_besides_taking_pictures_of/
|
{
"a_id": [
"c5pg9na",
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"text": [
"It's got a chemical sniffer, a laser, and a drill. All for looking for chemistry of one form or another that might indicate prior life, or the possibility of future life. And when it meets Spirit and Opportunity they can join to become MegaRover™!",
"Some instruments check for chemistry in rocks and sand. Some of it drilled, scooped and analysed, some of it at a distance with the laser.\n\nAnd there's some environmental sensors, like radiation, pressure, wind and particle detectors to see what's Mars' 'air' is really like. Also there's a device that tries to find traces of water.\n\nThis is to check for possible life on Mars, both previously as well as possible humans in later missions. And just to find out about how other planets work, this gives insight in our own planet Earth.\n\nHere's a nice [info](_URL_0_) on all the instruments (a bit techy though)\n\n*Science instruments are state-of-the-art tools for acquiring information about the geology, atmosphere, environmental conditions, and potential biosignatures on Mars.*\n"
]
}
|
[] |
[] |
[
[],
[
"http://mars.jpl.nasa.gov/msl/mission/instruments/"
]
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||
3maaew
|
When did a majority of Texans begin speaking English instead of Spanish?
|
While Texas was a Mexican state, I'm going to assume the official language was Spanish, but I know that many settlers (if Stephen F. Austin's 300 families and the large immigration from the US were any indicator) likely spoke Spanish as a second language at best. All documents I've seen from the independent Republic of Texas were printed in English. Was English the official language or merely the de facto language? Moreover, roughly how many used English as the primary language in their homes during the years Texas spent as a Mexican state, independent republic, and finally as a US state?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3maaew/when_did_a_majority_of_texans_begin_speaking/
|
{
"a_id": [
"cvdr903"
],
"score": [
10
],
"text": [
"Stephen Austin founded his colony in 1821. At that time, there were fewer than 8,000 Spanish-speaking *tejanos* and perhaps 15,000 Native Americans in Texas. These numbers should be taken with a grain of salt. Many of the Native Americans in Texas were nomadic and lived in Texas for only part of the year (or simply passed through from time to time while still considering it home). There were also a number of small isolated Spanish and American families and settlements who were in Texas specifically to avoid being counted or taxed (or arrested). \n\nWithin five years, Austin's colony numbered closed to 2,000 (including about 500 slaves), and was therefore already a very significant part of the population. \n\nAmerican colonists began flooding in during the 1820s - by 1831, Austin's colony had a recorded population of 20,000, so by this point the Americans (again, including their slaves) had overtaken Native Americans as the largest population in Texas. When Juan Almonte inspected the American colony on behalf of the Mexican government in 1834, he reported its population as nearly 25,000 - and this is the point where we can say a majority of Texans spoke English. \n\nEDIT: Source, [the Texas State Historical Association](_URL_0_). More info on Texas' population history there."
]
}
|
[] |
[] |
[
[
"https://tshaonline.org/handbook/online/articles/ulc01"
]
] |
|
1x6b0u
|
What source(s) (primary if possie) could be used as evidence for a paper on the Nazi regieme's efforts to conceal the Holocaust from the public eye?
|
I'm working on a paper on the above topic but am having some dificulty locating reliable scources on it. I have a few, such as a compilation of code words used by the Nazis in their writting (EG liquidating rather than murdering, etc) and an article about the temporary slow-down in persecution during the 1936 Olympics, but I would like to find more evidence to really drive home this idea. Do you have any suggestions on where to look, what to search for, or even specific sources if you can think of any? Thanks in advance!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1x6b0u/what_sources_primary_if_possie_could_be_used_as/
|
{
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"text": [
"Nazi-Germany did not try to conceal the holocaust in the east at all. Public mass shootings were common practice. Please read Mark Mazower's Dark Continent for background. \nThey did try to conceal the holocaust in the west however. Primary evidence could be the administrations of the different Jewish Councils and e.g. the Mauthausen death books. \n\nThe first shows you the administration of Jewish populations of European countries and the treacherous methods and terminology the Nazis used to push the Jewish populations voluntarily towards transit, work and death camps. The second example (available online) shows you the disguised terminology of the causes of death in KZ Mauthausen. It is very curious that nobody in Mauthausen is beaten to death and death penalties are described as: \"auf der Flücht erschossen\". But to have a solid case there you must match the official Nazi statement to eyewitness accounts. That is possible, but it takes time to go to the right archives and do proper research. \n\nAnother example: In the beginning the KZ administrations still used to send certificates of deaths back towards the city the prisoner once lived. After receiving repeated requests for the remains and personal belongings, the Nazi authorities stopped sending those certificates. Of course those poor individuals ended up in the crematoria and mass graves, so there was nothing to claim left. This is also provable, but again it will take time to investigate and visit the archives. ",
"The book entitled \"documents of the holocaust\" is sure to have a document that will help. It is a fat book with hundreds of primary source documents, set chronologically, so you can actually read through the slow grasp of the German state around the throats of the Jews and others. It's an incredible book I highly recomend.",
"My dad was born in 1929 in East Prussia. \n\nHe understood Concentration Camps to be like overflows for prisons where they put all the \"bad offenders\" like murderers, and spies. \n\nHe wrote a book on his childhood, [Farewell Marienburg] (_URL_0_). If you're interested, when I get home I can dig up the full excerpt."
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.amazon.com/Farewell-Marienburg-Claus-Neumann/dp/0595398251"
]
] |
|
34hu1p
|
What is the role of a neutral wire in an A/C? Does the return current in an A/C pass through the live or the neutral wire?
|
askscience
|
http://www.reddit.com/r/askscience/comments/34hu1p/what_is_the_role_of_a_neutral_wire_in_an_ac_does/
|
{
"a_id": [
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2
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"text": [
"It's the same as the role of neutral wire in DC: in order for the current to move, it has to have a conductor to move through.\n\nIn a closed circuit, there is no difference between the live and the neutral wire; the only real difference is that if the circuit is open, touching one will electrocute you (because that's the one that's connected to the power source), and touching the other will do nothing. (Assuming your feet are grounded.)",
"The neutral wire is like a ground. In North America, where most household appliances and electronics are 120 volts, the cable coming into the house has three conductors and a bare ground wire. The red and black wires are live and and 180 degrees out of phase. The white wire is neutral. \n\nFor the wall outlets and fixtures in the house, either the red or black wire is attach to the live side and the white neutral wire to the return side, providing a potential of 120 V. For clothes driers, electric ranges, and any other high voltage appliances, the red is attached to one side and the black to the other, providing 240 V.\n\nFor 120 V fixtures, the live wire is the one that is interrupted by the switch. When the switch of off, no current can reach the socket because the white wire only carries current it receives from the live wire."
]
}
|
[] |
[] |
[
[],
[]
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||
9f2v7g
|
how does glass work to help plants grow?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9f2v7g/eli5_how_does_glass_work_to_help_plants_grow/
|
{
"a_id": [
"e5texp3",
"e5tpykl"
],
"score": [
6,
2
],
"text": [
"What do you mean?\n\nLike greenhouses? They let in light and trap heat, allowing plants to grow in colder climates than they could otherwise.",
"Greenhouse design and construction is a fairly detailed science on its own. It varies based on your altitude, your agroclimatic conditions etc.\n\nGlass is almost exclusively used in temperate countries which get frost or snow during winter which is harmful to plants that are not tolerant of such conditions (flowers, fruits etc).\n\nIn warmer climates, plastic is used instead of glass, with features like side screens and top vents designed to maximise air flow and reduce ambient temperature.\n\nThe objectives of using glass (or any other material) in protected cultivation are:\n\n1) provide more suitable growing temperature, humidity to the plants\n\n2) absorb UV radiation from the atmosphere and filter the light entering the greenhouse\n\n3) prevent entry of pests and airborne pathogens into the plants"
]
}
|
[] |
[] |
[
[],
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||
22qlvb
|
why do red and blonde hair tend to run in the same families if there both recessive genes?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/22qlvb/eli5_why_do_red_and_blonde_hair_tend_to_run_in/
|
{
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"cgpgkkb"
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"text": [
"I'm not entirely sure of the allele frequencies of red/blonde hair but I'll continue regardless. By allele frequency I mean the number of people in the population who carry the particular gene variant/allele e.g. blonde/red hair\n\nThey must be at sufficiently high frequency that homozygotes (people with two copies of the blonde/red allele who therefore have blonde/red hair) and heterozygotes (Individuals who have the recessive allele for red/blonde hair and another dominant allele for e.g. brown hair) interbreed. \n\nFrom this homozygote heterozygote pairing 50% of their children will be blonde/red head.\n\nThere is another factor which comes into play called Penetrance. This is kind of a difficult concept to grasp. We're used to thinking of a trait (e.g. hair colour) being coded for a single gene, of which there are multiple alleles (brown, red, blonde etc.). However, in reality most traits are encoded for by multiple genes which work together to produce the trait. Therefore genes which encode for specific traits (e.g. hair colour) can be highly penetrant i.e. if you have gene X you will get trait X, or have low penetrance i.e. if you have gene X, there is a lower chance you will exhibit train X due to the influence of multiple genes.\n\nSorry if this is a sucky, explanation, I'm tired. What i'm trying to say is that blonde/red hair alleles must be in the population in a sufficient frequency for people carrying these genes to mate often, and it must be highly penetrant.\n"
]
}
|
[] |
[] |
[
[]
] |
||
1nkyiq
|
how does turning on a lightbulb use more electricity than keeping it running?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1nkyiq/eli5how_does_turning_on_a_lightbulb_use_more/
|
{
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"ccjio8h",
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"text": [
"There must be an initial surge of energy to get the filament to the proper temperature to produce the light. ",
"It all depends on how long you would be leaving it on for as opposed to possibly simply walking out and walking back in. MythBusters took this on!\n\n\n_URL_0_"
]
}
|
[] |
[] |
[
[],
[
"http://dsc.discovery.com/tv-shows/mythbusters/videos/lights-on-or-off-minimyth.htm"
]
] |
||
3bw7rl
|
What led to the development of marine infantry units?
|
I know my question may not be specific enough to warrant a specific answer, but I am curious about why there are infantry forces assigned to ships ("marine" units) if there are already combat-proficient sailors and land-infantry units that could accomplish the same function of combat. Why is there a need for marine-type units on a ship?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3bw7rl/what_led_to_the_development_of_marine_infantry/
|
{
"a_id": [
"csqp7es"
],
"score": [
2
],
"text": [
"This is a bit of a throughout history question, so it would be best to narrow it down. In broad strokes though there are advantages in having troops who are specialized in certain aspects of warfare, ready to deploy abroad, and under control of your branch of service. \n\nFor a lot of history in many places naval warfare consisted of mainly trying to ram an enemy ship, or board it and take it over. When it was time for boarding it helped to have people on board whose main job was exactly that. Also the distinction between a combat ship and a transport or merchant ship wasn't always very well defined. You can look at the battle of Dover for a good example of this. \n \nAt first the fighters on the ships wouldn't have been marine specialists, but as time moves on and more professionalism and specialization entered the military specific marine units emerged. The tactics and equipment used in boarding an enemy ship would be different from fighting in the field. \n\nAdditionally, from an organizational stand point it's much easier if everyone is in the same organization and chain of command. Joint Operations have issues with inter service rivalry/misunderstanding even today, and a ship would always need a contingent of marines for security, so why should they belong to some wholly separate organization?\n\nAs time went on the concept of amphibious warfare became a natural fit for marine units, and the ability to have an expeditionary force trained and equipped for such means that your country has the ability to apply land force anywhere it's navy can get to. "
]
}
|
[] |
[] |
[
[]
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|
1sgk3v
|
What tactics did viking raid victims come up with to counter the invasions?
|
Edit1: thanks for the response, i would also ask in military terms if any specific adaptations were made ?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1sgk3v/what_tactics_did_viking_raid_victims_come_up_with/
|
{
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"text": [
"In the Kingdom Wessex under Alfred the Great, the Burghal system was implemented in response to the Viking raids from Danelaw and overseas. The Burghal system in Wessex founded by Alfred in the 9th century, shown in the *Burghal Hidage* document, has 33 fortified towns, known as Burhs, in which local rural populations could take refuge during a raid and where local produce could be stored without risk of being lost to raids. The burhs also acted as market centres and a basis for which recruitment and taxes could be calculated. \n\n[Source](_URL_0_)",
"I can't speak for other Countries and rulers, but Alfred the Great of England built a series of fortified towns called burhs. Built nineteen miles apart all around the country they allowed for a garrison of Fyrd (Miltia comprising trained freemen).\n\n The burhs also served as a way to protect civilians from raids this turned Burhs into centers of market and trade which was important for raising Tax to support the Anglo military. \n\nBurhs were effective and ultimately allowed the Anglo-saxons to retake England since they allowed and quick local responce to the Hit and run viking raids and Since the Viking lacked siege weapons they were unable to successfully assault the Burhs. \n\nAlfred is also credited with strengthening the Anglo-saxon navy. The Anglo-saxon ships where considered larger and there carried more troops which allowed them to defeat the smaller viking vessels, that were built for speed and navigation. However Viking ships could easily outmaneuver the English ships in rivers, shallow water and low tides. \n\nUltimately these tactics were effective but failed to wipe out the viking threat all together. ",
"Best not forget the non-military means by which victims dealt with Invasion.\n\nIn the *Chronicon Aquitanicum et Francicum* (1028) more succinctly known as the *Historia Francorum* written by Adémar de Chabannes, it is noted how people, in the French Aquitaine at least, simply moved inland. Why bother building a fort and risk getting raided again when moving inland may prove a simpler solution?",
"Didn't Charles the Bald order the construction of bridges on the Seine to keep longships from going up the river into the interior? I thought I knew for a fact that we had a law about it, but don't have anything useful to hand. Idea being that by restricting the easy movement of the Vikings to the coast by shutting down the rivers, their impact and the cost of countering them could be minimized.\n\nEdit: [Edict of Pistres.](_URL_0_)",
"First of all this is my first post in r/askhistorians. Apologies if the formatting is incorrect, if I'm honest I'm procrastinating from doing reading on my thesis. I hope it's useful. The answer below focuses primarily on Ireland.\n \nSources: \nPrimary:\nAnnals of Ulster \nLife of Blathmacc \n \nSecondary:\nClarke, Howard B. 'The Vikings in Ireland: A Historians Perspective'. Archaeology Ireland vol. 9, no. 3 (1995), pp. 7-9. \n \nCróinín, Daibhí Ó. Early Medieval Ireland 400-1200. Essex, 1995. \n \nDoherty, Charles. 'The Vikings in Ireland: A Review' in Howard B. Clarke, Máire Ní Mhaonaigh and Raghnall Ó Floinn (eds.), 'Ireland and Scaninavia in the Early Viking Age'. Dublin, 1998, pp 292-311. \n \nDoherty, Charles. 'The Viking Impact upon Ireland' in Anne-Christine Larsen (ed.), 'The Vikings in Ireland'. Roskilde, 2001, pp 29-37. \n \n \n \n\nIn regards to how the Irish responded you have to understand how the Irish kingship system was structured at the time. There were tiers of kingship, though a king of a townland could act independently of an \"over\" king. Before initial Viking appearances in Ireland these kings raided monasteries in each others territories as a display of dominance. However, one important thing to note is that they did not attack the sanctuary in the middle of monastery, as it was sacred. This is important as it acted a place for monks to hide when such raids occurred. The Irish kings were also well aware on the limits in terms of destruction which they could incur.\n \nWhen the Vikings arrived, they were met with a non-unified resistance. If they defeated one local Irish king they gained very little in terms of land, and had to move onto the next local king, to fight again, for a small tract of land. In fact, the Vikings lost about as many battles as they won in Ireland. This style of warfare worked effectively against the Vikings versus the English system where a more unified form of kingship had grown. Once one king in England fell, the Vikings gained control of large tracts of land. \n \nThere is evidence that the Vikings were aware of the placement of Irish monasteries prior to their arrival, perhaps due to information gained in the Hebrides. They also became aware of what days to raid, as monasteries at this time served as proto-towns (Ireland had yet to develop what we would consider a town), but people gathered on feast days, and these were the days on which raids occurred. \n \nThe Viking response to the Irish system was to establish longforts on the boundaries between the Irish kingdoms, so they became a problem for both kings, but also neither as neither king wanted to deal with them. It was clear a raiding force was not going to be enough to gain a foothold in Ireland, as while in England there was infrastructure which could be taken and used, this did not exist in Ireland.\n \nThe Vikings then raided out from these longforts, attacking monasteries. This became an issue as initial raiders (pre-Christian Vikings) were unaware of the sacred nature of areas of these monasteries and burnt them in their entirety to the ground. This is demonstrated well in Walahfrid Strabo's 'Life of Blathmacc' in which the Abbott of Iona is murdered by the Vikings for refusing to show them to the burial site of Columba's remains. Round towers were not used as means of escape for monks, despite popular theory. Climbing into one is akin to climbing into a chimney with a fire lit in it. \n \nIt is clear that the Vikings became involved in the Irish political scene early on, as by AD 882 the Dublin Vikings had formed an alliance with the Southern Uí Néill and raided Armagh, but within seven years had made an alliance with the Northern Uí Néill to raid against the Southern Uí Néill.\n \nAs said above, the Irish response was disjointed, but violent and worked to the advantage of the Irish kings. Eventually the Vikings became naturalised (evidence at the Cherrywood site outside Dublin shows Viking farmers working land that had been used as farms from the Stone Age, meaning there was probably some form of intermingling). \n \nThe Dublin Vikings (as opposed to those in other longforts, who appear to have been separate groups) were expelled in 902 after Dublin was sacked. However, they returned in 917 and retook the city. The concept of expelling the Vikings is one which is subject to debate, as it appears the leadership was expelled as archaeological evidence shows the city continued to function. The assimilation of the Vikings can be seen further from this point on, as there are signs of intermarriage (through preserved records of names, which are hybrids), and intermarriage between kings, as can be seen with the three Gormlaiths, one of whom married high kings of Ireland. \n \nRaids by this point were also not focused on taking monetary tolls, or slaves, as the Annals of Ulster tell us in 853 the Dublin Vikings exacting tributes of cattle and grain from the native population. \n \nTo be specific in military terms, there's little available in Ireland to my knowledge. Armour piercing arrowheads have been found in Dublin having been manufactured by the Dublin Vikings, though these are unlikely to have been used in Ireland, as the Irish wore no real armour at the time of their arrival and there's no evidence to suggest that this changed much until much later. These arrowheads were likely being exported to England, or further afield as part of the Viking economic hub.\n \nOn a tangential note, the Battle of Clontarf was not all that significant in real political terms. It was used as a piece of propaganda by Brian Boru's descendants as they were losing power in Munster and labelled as the battle in which he drove the Vikings from Ireland. Vikings in fact fought on both sides of the battle, and were mercenaries. The battle was not about removing Vikings from Ireland in any manner. They were an accepted part of Irish society at this point. Yes, the battle resulted in the death of Brian Boru, the then-high king of Ireland, but it simply saw Máel Sechnaill restored as high king of Ireland (having been high king before Brian). \n \nIn summary, the Irish initial resistance appears to have turned into acceptance with the Vikings. The Viking raids and initial attempted land grabs failed due to the disjointed nature of Irish kingship, and thus became involved on a political and economic level with the Irish. The Irish response to this was to accept it. ",
"In ninth-century Frankia, one of the primary 'tactics' was paying off the Vikings to leave, as in this passage from the [Annals of St. Bertin](_URL_0_): \"852: The Northmen went to Frisia with 252 ships, but after receiving payment as large as they asked for, they headed off elsewhere\". Charles the Bald, king of West Frankia (most of present-day France) did this pretty frequently to buy off the invaders. The Northmen tended to strike at times of political division among the Franks, such as during the succession war between the sons of Louis the Pious that followed his death in 840-3, and again a few years after the death of Charles the Bald in 877. As noted below, Charles also promoted the construction of fortified bridges on Frankia's major river basins, since they were primarily getting in and plundering through the Seine and Loire river valleys. \n\nIt should be noted, however, that until the death of Charles the Bald, the Northmen on the continent seem to have been more of an annoyance than a serious threat. If you read the Annals of St. Bertin, a contemporary source that I cited above, you'll find a great many mentions of the dealings between Charles and his stepbrothers/rival kings, and not very many of the Vikings. Unlike in England, the Vikings do not appear to have settled and stayed on the Continent, with the exception of a few islands in present-day Netherlands (such as Walcheren, today not an island anymore) and Normandy, which they were granted after cutting a deal with Charles the Simple. \n\nOne other thing: Monasteries were one of the primary targets of Northmen's raids, since they were often located on the river valleys and generally had plenty of silver and few capable warriors. To get away from this, some monasteries moved upriver or away from the rivers entirely. \n\nEdit: Wallachia -- > Walcheren"
]
}
|
[] |
[] |
[
[
"http://www.ucl.ac.uk/archaeology/research/projects/burghalhidage/hidage"
],
[],
[],
[
"http://www.litencyc.com/php/stopics.php?rec=true&UID=6966"
],
[],
[
"https://classesv2.yale.edu/access/content/user/haw6/Vikings/Annals%20of%20St%20Bertin.html"
]
] |
|
1mw4ch
|
If water conservation is so vital to mammals, why do we pee? Why not transfer toxins into stool and recycle the water? Are there any animals that have evolved to do this?
|
Bizarre thought I had upon waking up that is now bothering me a great deal.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1mw4ch/if_water_conservation_is_so_vital_to_mammals_why/
|
{
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"Safely excreting waste tends to be a balancing act between water and energy. Land animals in non-desert climates tend to urinate in the sense you are familiar with. However, animals in climates in which water is very precious or those which can't carry a lot of water due to weight (birds) use a different method of getting rid of waste. \n\nA large part of what we're getting rid of in urine is nitrogen waste so that we don't build up ammonia. We get rid of nitrogen by making a compound called urea in a cycle called the urea cycle. It uses some energy to make, and takes a lot of water to get rid of. In contrast, birds, reptiles, and some desert mammals get rid of nitrogen by making a different compound called uric acid. This takes more energy, but can be excreted as a paste with only a little water in it (this is the white part of bird poop). It's a balancing act as to whether the water or the energy is generally more important, and so different species have gone different ways.",
"Urine production and stool production are two completely separate processes. As blood flows through your body, it is constantly passing through the glomerulus in the kidneys. The glomerulus is a network of capillaries that is extremely high in pressure. In simple terms, what this does is push water and ions (sodium, potassium, etc) into the next region of the kidneys - the nephron. \n(I am describing the following processes in an extremely simplified way.)\nThe nephron is basically a tube that allows the water/solutes to pass nearby capillaries and diffuse back into the blood if the concentration in the blood is low. If it's high, these solutes are not necessary and so they remain in the nephron. This also attracts other charged ions to pass into the nephron if need be, which will then all flow into the bladder to be excreted. \n\nNow, stool production happens in a completely different area of the body. As food is digested, it moves from the stomach into the small intestines where all the nutrients are absorbed in the bloodstream. After the small intestine, the food passes into the large intestine, which is responsible for water removal from the food. The large intestine removes most of the water and what's left is basically feces. As you can see it would be quite difficult to combine these two processes. \n\nIn order for the ions to be excreted, they need to be dissolved in something that will flow out of the body. It would not be possible to eliminate dissolved substances without staying in solution. As far as I know, the closest animal able to do such a thing are birds. They excrete a urine/fecal matter mixture all at once, rather than two separate processes. But I don't know much about the workings of a bird's waste removal system so my knowledge is limited there.",
"Some desert reptiles excrete semi-solid uric acid to conserve water. I remember reading long ago that there was a small South American deer or antelope that did this too, but a google search turns up nothing but reptiles and birds. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
uorc1
|
Why do dogs walk in a circle before they lay down?
|
askscience
|
http://www.reddit.com/r/askscience/comments/uorc1/why_do_dogs_walk_in_a_circle_before_they_lay_down/
|
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"text": [
"There are a couple of theories ranging from circling behaviour intended to pad down grass to be more comfortable, to circling in order to judge wind direction and lay nose facing the breeze. There's little conclusive agreement on the true reason however.",
"I don't see any scientific papers but here is a link to a video of wolves going to sleep. As you can see they do not all circle but rather make beds for themselves.\n\n_URL_0_",
"Had a quick search, this is the best I could find.\n\n\n > Wisconsin State Journal (Madison, Wisconsin)\n > \n > February 7, 2008 Thursday\n > ALL EDITION\n > \n > DOGS CIRCLE AND CATS KNEAD BEFORE NAPPING\n > \n > SECTION: LOCAL; CURIOSITIES; Pg. B1\n > \n > LENGTH: 176 words\n > \n > Q. Why do cats walk in a circle before they lie down?\n > \n > - Submitted by Larry Haynes, grade 6, Whitehorse Middle School\n > \n > A. Circling behavior seems to be more ingrained in dogs than cats. Cats tend to knead with their claws when they are happy and settling down on a favorite person's lap or to nap.\n > \n > The kneading behavior may be a throwback to baby behavior, as kittens knead when nursing to speed the flow of milk.\n > \n > Dogs, on the other hand, may walk in circles as part of a \"nesting\" behavior, sort of like \"fluffing our pillow and adjusting the blankets to make the area comfortable,\" said Sandi Sawchuk, UW-Madison School of Veterinary Medicine clinical instructor.\n > \n > This circling may be an artifact, an ingrained behavior, from the time when the wild ancestors of domesticated dogs slept in the open. Circling would serve to tamp down tall grasses and other obstructions.\n > \n > Sawchuk noted, however, that not all dogs do this. Some are simply \"ploppers,\" and some, like dachshunds, are burrowers and \"like to slip under the covers and curl up next to the owner's feet.\"",
"[Straight Dope seems to know](_URL_0_)\n\n > \"The trick to understanding any domestic animal 'stereotypical' behavior is to imagine its value in the wild. A wild dog will often sleep in the open, and walking in a circle before you lay down is a good way to tramp down the vegetation a bit to make a more comfortable \"bed.\" It's also possible that dogs, being social, sleep together and circling is a way of marking out territory and making more room--one of those obviously 'hard-wired' things that haven't yet been bred out. "
]
}
|
[] |
[] |
[
[],
[
"http://youtu.be/fsBNDvWGvAU"
],
[],
[
"http://www.straightdope.com/columns/read/1652/why-do-dogs-circle-before-lying-down"
]
] |
||
574jsf
|
In US Presidential election history, has there been cases where the losing candidate completely refused to recognize the results of the election?
|
And if so, what happened? How did they bring it to a resolution?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/574jsf/in_us_presidential_election_history_has_there/
|
{
"a_id": [
"d8outqg"
],
"score": [
9
],
"text": [
"Hi there, I'm going to approve this question because it asks about the historical record, but for potential respondents: Please remember that our subreddit rules explicitly forbid both [discussion of current events](_URL_1_) as well as [political discussion/soapboxing](_URL_0_)."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/wiki/rules#wiki_no_political_agendas_or_moralising",
"https://www.reddit.com/r/AskHistorians/wiki/rules#wiki_no_current_events"
]
] |
|
bwz9km
|
how did columbus communicated with the aztecs if they didn’t speak their language and vise versa?
|
Edit* I meant Hernan Cortes not Columbus. I have failed my history teachers!
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bwz9km/eli5_how_did_columbus_communicated_with_the/
|
{
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"text": [
"Columbus didn't communicate with the Aztecs. He never met them. \n\nHernan Cortes was the man responsible for destroying the Aztec empire. \n\nWhen Cortes first landed in the Yucatan he met Geronimo de Aguilar, a Spanish Franciscan priest who had survived a shipwreck followed by a period in captivity with the Maya. This priest had learned the Mayan language. \n\nLater, Cortes fought and beat the Tabasco natives. They gave him 20 women. One of which was called La Malinche and would become Cortes' mistress. She knew the Aztec language and the Mayan language, so Cortes was then able to communicate to Montezuma of the Aztecs through these translators."
]
}
|
[] |
[] |
[
[]
] |
|
ttkq4
|
Are new planets and stars currently being formed?
|
Same as title. I know that the Universe is, or at least the theory is that it is, expanding. So the distance between objects is increasing. Also know that stars go Super-nova, die, planets explode, and black holes form and swallow things up. But are there places in the Universe where new stars and planets are create?
If there aren't - doesn't that mean that at some point in time in billions and billions of years every star in the Universe will be dead. Every planet will "die" (whether be destroyed or any life killed due to no stars)....
|
askscience
|
http://www.reddit.com/r/askscience/comments/ttkq4/are_new_planets_and_stars_currently_being_formed/
|
{
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"c4plmev"
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3
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"text": [
"There are new planets and stars being formed all the time. And old ones being destroyed. We cannot directly or even indirectly observe most of this due to the distance between our solar system and these other systems and galaxies, but it is happening. In fact everything we are composed of, all of our atoms and those comprising our planet and sun, are from a now dead and Super-nova'd star. \nCheck out this video for some cool insight into the idea.\n_URL_0_"
]
}
|
[] |
[] |
[
[
"http://thechive.com/2012/04/18/a-fascinatingly-disturbing-thought-video/"
]
] |
|
b9x26m
|
how integrals can calculate areas?
|
im new here so im sorry if this doesnt belong here, but this question is driving me crazy all the explanations i could find are pretty complex, im suppoused to imagine an infinite amount of squares or something like that? but than, how could it ever be accurate?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/b9x26m/eli5_how_integrals_can_calculate_areas/
|
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"There is a 2d area underneath the curve of a function, or in between functions. There are also 3D volumes under and between curves, the x, y, and imaginary z axis. \n\nNow, when you want to find these curves you have to use a tool, which is the integral function. \n\nIntegrals can approximate area and volume, among other things. \n\nThe way that works is by creating infinite shapes of the same area, and including those under the curve in the final calculation and discarding the others using the FTC. \n\n\nAnd I can’t give you a better explanation because this is all I truly understand. ",
"How could anything less than ~~infinity~~ the limit as infinity is approached be accurate?\n\nOr, rather, to find the area under line f(x)=1 between 0 and 1, you could use as few subdivisions as you wanted and still find the accurate answer. But the magic of going to that limit is that it always becomes accurate unless it's a bullshit function without a describable area at all. Consider f(x)=x and your left-handed Riemann sums will always underestimate, and your right-hand sums always overestimate, unless you proceed to that limit and it becomes the accurate answer either way.\n\nIt sounds like you're still on the early chapters of integration, though. Just like with derivatives, you will first learn the ugly-if-truthful way the integration rules are found, after which you will simply memorize the already-ugly-derived rules which are much easier to make use of! So don't worry even if you kinda flunk this section, the next ones will be easier.\n\nThe integral of f(x)=x is\n\nThe integral of f(x) = x^(1) which is a power, so use the power rule: int(x^(n)) =(1/ (n+1))×x^(n+1) + *c*\n\nIt is F(x)=(1/2) × x^(2) + *c*",
" > how could it ever be accurate?\n\nAs you add more rectangles the closer you get to the true answer (because each rectangle will better approximate the curve). The more rectangles you add the closer the \"error\" is to zero. \n\nOnce you have an infinite number of them the error *is* zero. If you know what limits are it's quite literally the same thing. If every step has you get closer to reality, and you take an infinite number of steps, you'll get infinitely close to reality, which means you've arrived at the correct answer. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
9cbbms
|
Seeking for the translation of what Diogene said to Alexander the Great.
|
First thing first sorry if this is the wrong place to ask this, but I spent the weekend looking for solution but couldn't find one.
For a project (illustration) I am looking for the ancient greek translation of what Diogene the Cynic said to alexander the great "Stand out of my sunlight".
Problem is I don't speak greek at all and either I found the full text from plutarch or just english translation without the sources.
I may have found a solution but couldn't verify it (and can't write it here as I don't know how to write in Cyrillic on my phone).
Thanks in advance and sorry if this was not the good place for this question.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/9cbbms/seeking_for_the_translation_of_what_diogene_said/
|
{
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"text": [
"If I understand you right, you're asking for the Greek text? That's in Plutarch's Life of Alexander, 14.3. It looks like this:\n > ‘μικρὸν’ εἶπεν, ‘ἀπὸ τοῦ ἡλίου μετάστηθι’\n\nεἶπεν is \"he said.\" So actual quote would be ‘μικρὸν ἀπὸ τοῦ ἡλίου μετάστηθι’\n\nWriting Greek on an American keyboard is a pain in the ass. There are a couple of fonts available for it (TAPA uses GreekKeys, for instance). Honestly the easiest way I've found is to find the text online and copy and paste. I got this text from the [Perseus Project](_URL_0_). You may like to see that this site has the Greek text and the English translation, if you open the panel on the right."
]
}
|
[] |
[] |
[
[
"http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A2008.01.0129%3Achapter%3D14%3Asection%3D3"
]
] |
|
e1gesn
|
Is there number to acceleration of Universe expansion?
|
I mean, velocity of expansion is the Hubble constant. The value of it is found in Wikipedia.
But how one expresses the acceleration of the expansion? Is there observational number to it? How large is this number?
|
askscience
|
https://www.reddit.com/r/askscience/comments/e1gesn/is_there_number_to_acceleration_of_universe/
|
{
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"f8sr5td"
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"text": [
"The expansion rate has units of inverse time (for practical reasons it is given as km/(s\\*Megaparsec) but that is a length in numerator and denominator). How the expansion changes over time has units of inverse time squared: 1/s^(2).\n\nIt can be calculated with the second [Friedmann equation](_URL_0_). In the distant future the density (and pressure) of matter should become negligible and we are left with the cosmological constant only (assuming it is actually constant). Its value is about 1.1\\*10^(-52)/m^(2), multiplied by c^(2)/3 we get 3.3\\*10^(-36)/s^(2). That is still a weird number, but its inverse square root is about 17 billion years, and in the distant future (when distances increase as exponential function) that will be the time in which distances increase by a factor e."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Friedmann_equations#Equations"
]
] |
|
3u9lci
|
how does the same model of device get software updates at different times during a rollout?
|
When a company releases a software update, sometimes they "roll it out" over the course of a few days. How does it become available to one device on Day One and an identical device not until Day 3?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3u9lci/eli5how_does_the_same_model_of_device_get/
|
{
"a_id": [
"cxd1cdo"
],
"score": [
3
],
"text": [
"Every device had a unique serial number. The device sends its serial number to the update server which uses it to decide whether the device gets an update. "
]
}
|
[] |
[] |
[
[]
] |
|
3oc4ms
|
do "not for individual sale" warnings on products have any legal binding?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3oc4ms/eli5_do_not_for_individual_sale_warnings_on/
|
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"text": [
"The point of the label is that required legal statements (like nutrition and ingredients) aren't on the individually wrapped servings but rather on the box they came in. These warnings protect the manufacturer from charges that they made items without the required labeling.",
"If you look on each individual item they're usually missing a sell by date too therefore making them illegal to sell (that's how it works in France at least) ",
"Usually this means \"*not labelled* for individual sale,\" for example if nutrition facts are not disclosed. Private resale is usually still legal, because most laws about food sales only apply to commercial operations of a certain size.",
"I used to go to a little greasy spoon cafe for lunch, all of their drinks cans and crisps were multipack \"not for individual resale\". Noone cared, though they were closed down as they encroached on the business park canteen catchment area.\n\nI thought it was more to do with cost, a 50 pack box of crisps is £12 at a wholesaler, yet you can often get 6 packs for £1 at the supermarket, 8x6 is 48 packs for £8. Yes they're smaller (and 2 packs short), but its 50% difference."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
449bxo
|
why couldn't martin shkreli call the committee of congressmen imbeciles right at the hearing ? can he invoke his 5th amendment and still them to go take a hike?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/449bxo/eli5_why_couldnt_martin_shkreli_call_the/
|
{
"a_id": [
"czoie5b"
],
"score": [
8
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"text": [
"Just like contempt of court, you can be fined or jailed for contempt of congress.\n\nYou have to respect the proceedings even if you do not respect the people."
]
}
|
[] |
[] |
[
[]
] |
||
4su7xl
|
why does a knife need to be moved to be sharp? if you touch a knife it's ok, but if you drag your finger down the edge it hurts.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4su7xl/eli5_why_does_a_knife_need_to_be_moved_to_be/
|
{
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"Knives are still sharp straight-on and can cut that way. However, at a microscopic level, even straight-edged knives have tiny teeth. So when you move the edge against the item to be cut, you are actually running a tiny ultra-sharp saw across it.\n\n[Micro photo of a razor's edge can be seen here.](_URL_0_)",
"On the microscopic level, the edge of the blade is jagged. Same with your skin or just about any other surface. So when you pull on the blade, all those molecules rub up against each other, causing the hard metal molecules of the knife tear at the softer surface.",
"I have a follow-up question to tag along with this:\n\nLet's assume I have a blade that we've been able to sharpen away all the jagged edges all the way down to the atomic level. Will this knife cut the same way? ",
"Assuming you have a properly sharpened knife, the ability to cut anything is based on pressure - the same reason you can drag a utility knife through cardboard and it will cut instead of having to use a sawing motion. The ease of cutting depends on edge sharpness (defined by molecular structure and sharpening methods) and blade geometry - but that is for another day.\n\nOn a properly sharpened knife, you can cut quite a bit with relatively little to no pressure - you can drop a human a hair on the edge and the weight of the hair is enough for it to be severed in two. So technically, touching a knife (depending on how much pressure you put and how sharp the edge is), could cut you. In reality, most cuts from truly sharp knives are realized after the fact - they cut cleanly and blood doesn't appear for a split second or two.\n\nTL;DR Dull knives need sawing motions to cut things; properly sharpened knives can push cut.\n",
"A lot of wrong or incomplete answers here. Let me clear this up by explaining normal and shear stresses. \n\nA knife is sharp regardless, the issue is the way the stress (force per area) is applied. When you push down on a knife you are only putting normal stresses (that is to say, a force perpendicular to the surface of your skin over the cross sectional area of the knife edge) on your finger. When you drag the knife, in addition to these normal stresses you are also putting your skin under shear stress. Shear stress is the force per unit area that is parallel to the surface of your skin. \n\nWhen I say force per unit area, I mean something conventional like psi (pounds per square inch). However, you can imagine that at the very tip of the blade the surface area is extremely small. When the surface area is very small you exceed the strength per unit area (think of this as the force that can be applied over a region before it breaks) of your skin and you get cut. This is why a bullet can kill someone but something about 10x the size with the same energy might knock you out - the force per unit area is reduced even though the force is the same. \n\nNow you can visualize a needle, which has a very small surface area parallel to the surface of your skin - it looks like a tiny circle. It can poke you but you probably cant cut anyone like a knife with it because the cross sectional area (the view you would see if you were looking at the needle in 2D) perpendicular to the surface of your skin is much larger and rectangular. The normal stresses are very high but the shear stresses are not very large.\n\nIn short:\nA knife when slid across your skin applies forces both parallel and perpendicular to your skin AND the cross sectional area of the knife tip parallel to the surface of your skin is very small, increasing the shear stresses and cutting you.\n\nEDIT:\nhere is a picture of various cross sectional areas so you know what I mean. Without taking pictures or access to a cad program I cant make a good one. \n_URL_1_\n\n_URL_0_\n\nThe second picture is the cross sectional area you would see in shear.\nThe top picture is what you would see in normal stresses.",
"For the record if you have a sharp enough knife you can cut yourself on it by touching it, ie. without a sawing motion.\n\nHigh end carbon steel chef's knives do that pretty often. I'd assume things like obsidian scalpels would as well.",
"It depends on the knife. A very sharp knife can actually cut a handkerchief dropped on it. \n\nThe reason that slicing with a knife cuts better is because of the very small teeth of metal along it's very edge. Because of the structure of the metal, and the way it's sharpened, it doesn't create a smooth edge. There are tiny little burs and teeth that stick out from the edge unevenly and these are what do the cutting.\n\nWhen a knife starts to get dull and you see somebody use a chef's steel or a leather strop, it's not sharpening the knife by removing any material, instead it's taking the bent teeth on the very edge and standing them back up in the same direction. Then as you use the knife they will start to get bent again, dulling it. Eventually many will snap off, or become so bent they can't be bent back with stropping and this is when you need to actually sharpen the knife by removing material like with a stone or tool. \n\nNow the rougher and larger these little teeth or whiskers of metal on the edge are, the harder it is to begin the cutting motion. If you use a coarse stone you get coarse teeth. If you use a very smooth stone, and then you strop the blade with some rubbing compound, it creates a very smooth, polished edge with very small teeth that are more uniform in size and it makes it easier to cut. This is what puts a razor edge on a knife allowing it to shave hair off easily. \n\nThe very smoothest edges are so sharp that you do not need to slice or saw; simply touching the blade to something will begin to cut. \n\nThere are also different shapes of knife edges that give them different properties. A katana for instance has a rounded shape kind of like the pope's hat. This shape causes it to spread something as it cuts into it, reducing resistance and allowing the cutting edge to cut with less friction. This allows a katana to cut through very tough or thick material without slowing down much in a swing. \n\nContrast this with the edge of a scalpel which looks more like a V and allows for very fine cuts and a lot of control for very precise work like surgery. \n\n\n\n",
"As my mum explained to me when I was a kid, slicing is all about speed. \n\n\n\n\nRun fast enough, and you can get sliced by blades of grass. ",
"An expert knife maker can make a knife so sharp that it will cut you at the slightest touch."
]
}
|
[] |
[] |
[
[
"http://www.asharperrazor.com/wp-content/uploads/2011/05/knife-edge-300x240.jpg"
],
[],
[],
[],
[
"https://upload.wikimedia.org/wikipedia/commons/thumb/f/fe/Japanese_knife_blade_types_B.svg/2000px-Japanese_knife_blade_types_B.svg.png",
"http://www.skwirk.com/content/upload/images/Secondary/NSW/Year_10/Maths/volume/Topic1/Chapter1/brief1_crosssection.jpg"
],
[],
[],
[],
[]
] |
||
1facnp
|
If one of an entangled pair of particles is entangled again, what happens to the entangled values in the system?
|
Say two electrons are entangled by spin, so one is spin-up and the other down. Is it possible to entangle one of these two with a third electron, by spin, without collapsing the state of the system first?
If it is possible to "double entangle" an electron in this way, is it viable to reason about the individual states of the three electrons? Is there a higher probability of one spin value over the other, for example?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1facnp/if_one_of_an_entangled_pair_of_particles_is/
|
{
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"ca8hfsb"
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"score": [
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"text": [
"Three electrons can be maximally entangled as \n\nuuu + ddd\n\nuuu + ddu + dud + udd\n\nuuu + udd + duu + ddd\n\nThese are all [GHZ](_URL_0_) states. They're triply entangled, so there are no 'individual states'. Any single measurement of any electron has a 50/50 chance of being up or down. Some measurements of one of the three will pin down the values of the other two along the same axis, other measurements won't.\n\nIf you're starting with (ud - du), which I assume is the state you're talking about, and intent on keeping it, then all you'll get is a product state of the entangled pair and the third electron."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Greenberger-Horne-Zeilinger_state"
]
] |
|
eo7a0t
|
as alcohol sterilizes stuff, when we drink booze it kills the good bacteria inside us?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/eo7a0t/eli5_as_alcohol_sterilizes_stuff_when_we_drink/
|
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"text": [
"Alcohol is absorbed in your small intestines and subsequently processed and broken down enzymatically by your liver long before it reaches your colon. The colon aka large intestines is where your gut bacteria live predominantly",
"Rubbing alcohol is like 60-80% in order to be effective. Drinking alcohol of 10% or less will have virtually no effect. Any amount you drink would be immediately diluted to no effect.",
"No, but it does prevent the drink from getting most bacteria, thats why on times when the waters could get dirty or poisoned often it was 'healthier' to drink wine.",
"Alcohol we drink is not concentrated enough to have a significant effect on mouth, gut, or blood bacteria. Even if you drink really strong spirits, by the time it gets through your stomach it has mixed with a lot of other fluid (and solid food) which heavily dilutes it. The only exception is mouthwash, which works on your mouth and throat, but that's not suitable for drinking."
]
}
|
[] |
[] |
[
[],
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[],
[]
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||
1ph2rw
|
Does capillary action take salt water with it? Why or why not?
|
Since the salt molecule is heavier than the H2O, it seems like the height it could travel up something like string or paper would be less than freshwater.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ph2rw/does_capillary_action_take_salt_water_with_it_why/
|
{
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"cd2bn8o"
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"text": [
"Yes, the water drawn up by capillary action would take the soluble salt with it, but you are right that the slightly larger mass of the sodium and chloride ions, compared to water, will make them \"climb\" slower, and therefore less high.\n\nThis is the basis of some types of molecular separation mechanisms/experiments, such as [paper chromatography](_URL_0_) or [thin-layer chromotography](_URL_1_). You take a solvent solution with some dissolved molecules you want to separate (called the \"mobile phase\"), and allow the liquid to climb through a thin layer of some absorbent material (called the \"stationary phase\") by capillary action. The larger a molecule is, the less it will move up through the stationary phase in a given amount of time."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Paper_chromatography",
"http://en.wikipedia.org/wiki/Thin_layer_chromatography"
]
] |
|
2x9dnc
|
how is it possible for something moving the speed of light to experience no time.
|
I was recently listening to star talk and Neil deGrasse Tyson noted that light is simultaneously at its starting point and its destination because something moving the speed of light experiences no time. I can't really get my head around this. We can measure the fact that it takes light 8 minutes to get from the Sun to the Earth. How can that 8 minutes be different from the perspective of the light? I would assume (wrongly I suppose) that increasing speed only changes the distance you travel in an amount of time and shouldn't change how much time you feel like that takes.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2x9dnc/eli5_how_is_it_possible_for_something_moving_the/
|
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"The concept at play here is called Special Relativity; it's one of Einstein's greatest achievements.\n\nThe ELI5 is that time slows down for *all* moving objects. You don't notice this on a day to day basis because you're moving *really* slowly; you need to be moving at a nontrivial fraction of the speed of light for the effects to become noticeable.\n\nBut, for example, if you were to get in a spaceship and go at .99 times the speed of light and take a 1 lightyear trip that ended up back at Earth, we on Earth would have to wait a year for you to return, but it would only seem like about two months to you on the ship.",
"Yep, it's wrong. We like to think of velocity as being a simple thing. If you are going to a place X miles away, and you go x miles per hour, you get there in an hour. if you go x2, you get there in half an hour and so on.\n\nAt every day speeds, this works, because the difference is so small, you'd never notice it, even adding it up through an entire lifetime.\n\nBut at relativistic speeds, when you are moving a sizable fraction of the speed of light, this is no longer true.\n\n\n > shouldn't change how much time you feel like that takes.\n\nMore confusingly, it doesn't change how much time you *feel* it takes. To you, time is always 1 second, per 1 second. It *literally changes how fast your time moves* in comparison to that of some other frame of reference. \n\nTo you, one second per second will have passed for the entire trip. But to someone moving at a vastly different velocity, you will see their time as moving more slowly than your own. They, in return, will see your time as having moved more slowly than their own. \n\nA way I have tried in the past to visualize this:\n\nWe can observe that the speed of light in a vacuum is a constant, it moves at c for all observers. For simplicity, let's say c is 10 miles per hour.\n\nIf you shine a flash light beam so that one photon shoots out, you'll see it travel away from you at 10 miles per hour.\n\nIf bob is driving by in his car at 5 miles per hour, he also sees the photon traveling away from him at 10 miles per hour.\n\nSo after an hour, both you and bob see the photon as 10 miles ahead. but bob was moving past you at 5 miles per hour, so he's 5 miles ahead of you. So his photon, 10 miles ahead of him, is 15 miles ahead of you. \n\nHow can one photon be in two places at once? It can't.\n\nWhen your wristwatch says an hour has passed, you can see Bob's dashboard clock has only registered half an hour, so to you the photon is 10 miles down the road, and to him that makes sense, because it hasn't had enough time to get to 15 miles down the road, because an hour hasn't passed for him.\n\n If you are watching the clock on bob's dashboard, it is running slow. When his clock shows an hour has passed, from your perspective it has taken 1.5 hours. So you'd expect to see the photon be 15 miles down the road, and again that matches up with Bob, since he has experienced 1 hour and it is 10 miles ahead of him, 5 miles down the road. \n",
"The best way I've heard it explained is to imagine a flat, 2d spacetime with 1 space & 1 time dimension each.\n\nIt's a flat field where \"time\" is north, and \"space\" is east. Your speed in each direction adds up to c, which is the speed limit. N+E=c\n\nSo when you are not moving through space, your speed is N+0=c.\n\nAs your speed through space increases, your speed through time must decrease. Just as when you turn towards the east while driving north through a field. Your speed in the north direction is reduced from the pov of an outside observer, even if you feel like you're always going the same speed.\n\nWe just have three more spacelike dimensions. To a photon, since its speed in the space dimension is always c, it's internal time dimension is 0. ",
"The newest Vsause video has a pretty good ELI5 description.\n\n _URL_0_",
"Watch this, Vsauce explains it really well ! - _URL_0_"
]
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|
[] |
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[],
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"http://m.youtube.com/watch?v=ACUuFg9Y9dY"
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"http://youtu.be/ACUuFg9Y9dY"
]
] |
|
hah51
|
Do new scientific discoveries have the same relative significance over time?
|
Would the (potential) discovery of the Higgs Boson have the same relative significance to us as the discovery of gravity by Newton in 17th Century or the invention of the wheel in the 4th Millenium BCE.
In other words, in a few thousand years from now would the Higgs Boson seem as trivial to the scientists of the future as the wheel seems primitive and trivial to us *or* is the significance of scientific discoveries non-linear in time.
|
askscience
|
http://www.reddit.com/r/askscience/comments/hah51/do_new_scientific_discoveries_have_the_same/
|
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"It would be *incredibly* less significant to us than Newton's laws of gravity or the invention of the wheel.\r\n\r\nWhat many people don't realize is that we've basically mapped out all the physics that will ever be relevant to humans. There are still holes on the edges of our theories, but filling them in won't *do* anything at scales humans will ever reach outside of some physics lab. Whether or not the Higgs boson is discovered will not affect the daily life of anyone who is not a physicist.",
"Its hard to say really. Especially in a few thousand years. As technology becomes more complex, so does the physics needed. While I am not sure what role our understanding of the weak and strong forces will play in our technological advancement, I feel quite confident that Quantum Electrodynamics will become important, maybe very soon. These 3 things comprise our fundamental understanding of how the universe works on a Quantum level, and right now we need the Higgs to complete that understanding. And as I have said before the Higgs mechanism plays a huge role in many many other areas of physics, which are well understood. It isn't a trivial concept and has wide sweeping consequences that range from how the ice you put in your drink forms, to how the universe as we know it began. ",
"It's important that we not mix up science and engineering. There's a lot of cross-pollination, obviously, but they're different things with different goals and means.\n\nBroadly speaking, things can happen in one of two ways. Either we learn something new, then seek (and maybe find, maybe not) ways to apply that knowledge for something other than more knowledge, or we discover that we can do something and then seek ways to explain that something abstractly.\n\nThe wheel wasn't a *discovery.* Nobody sat down five thousand years ago and worked out the differential geometry of the circle. It was a pure invention: hey, round things roll. Neat.\n\nLikewise, the Higgs isn't an invention. It has *zero* practical applications. It's pure discovery. Oh look, here's why weak bosons have mass while the electromagnetic boson doesn't. Neat.\n\nSometimes inventions lead to knowledge, but not always, and not right away. The Minoans had flush toilets three thousand years before anyone wrote down the Hagen-Whasisname equation for laminar fluid flow through a pipe. You don't always need to be able to understand something completely to make use of it in ways that change the world.\n\nSimilarly, not all knowledge is applicable. For instance, how would the world be different if we had never discovered that other galaxies exist? It wouldn't. Not in the slightest. Well, okay, maybe in the slightest. Some of our fiction would be different, and theoretical cosmologists would have to find proper jobs, and awkward teenagers the world over would have different posters tacked up in their rooms. But in terms of actual day-to-day life? Zero change. But at the same time, discovering that the universe is filled with galaxies opened up the door to *tremendous* understanding of the universe and how it all works, trickling down to all sorts of things like current work on extending the Standard Model of particle physics.\n\nSo how do you quantify \"significance?\" Will the Higgs change lives? Almost certainly not, at least not in any direct way. Is it important anyway? Absolutely. It's a piece of the puzzle that we're slotting into place, advancing the goal of someday being able to say we have a complete understanding of the laws of physics. That's something."
]
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[
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|
3sv8u1
|
the metal thing they press on fighters faces between rounds.
|
Between rounds, there's always a guy that presses a metal plate thing on the fighters face. What and why?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3sv8u1/eli5_the_metal_thing_they_press_on_fighters_faces/
|
{
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"I believe it's cold like ice to decrease the swelling. Probably made of steel so it can be sterilized between fights.",
"It's an eye iron. It's a piece of steel that can be super-cooled to reduce swelling on a fighter's face, so they can continue to see throughout the match.",
"Hits to bony areas usually cause large swelling very quickly. There is no fat/muscle to blunt the force. \n\nThe piece you see is actually an \"eye iron.\" It is simply a cold piece of metal. That piece is applied and pressed into the swelling to minimize/reduce it. \n\nIt literally \"pushes\" the swelling down. \n\nThe cold helps, but the force is what really does the trick. \n\nYes, it hurts like hell. \n\nSide note: the method of pushing in swelling isn't just for fighters. A doctor once did it for my niece, in the ER, after she fell and hit her head on the corner of a table. We rushed her to the ER because it swelled up to the size of a softball in under 5 minutes. It was intense to watch. \n\n\n\n\n"
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
6yjzd1
|
what's the deal with all those scammy looking "we buy houses" signs i see at so many intersections?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6yjzd1/eli5_whats_the_deal_with_all_those_scammy_looking/
|
{
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"They buy houses. Why do you think them scammy?",
"Opportunists. Lowball offers. If seller is motivated they get an easy and profitable flip.",
"They are looking for people in danger of foreclosure. It costs $5 for the sign. If they get one deal out of it, it was worth it. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
3vbo9y
|
why do skilled nfl athletes still commit penalties?
|
I'm thinking in particular of something like grabbing a face mask. Is there some benefit to it that outweighs the penalty? Does it just happen too fast? I don't think that a player could grab one without knowing it, but I guess so?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3vbo9y/eli5_why_do_skilled_nfl_athletes_still_commit/
|
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"Sometimes it is on accident and sometimes it is not. If I go to grab someone and they move at the last second, I may not grab them where I was trying to. Everything is happening so fast, and other times they just want to grab the face mask. ",
"Facemasks normally are inadvertent. Holding happens almost every play. I would have gone so much further if I learned how to hold and not get caught. \n\nNow though, there are so many new rules it makes the game flag football...\nSometimes the penalties are intentional if tempers are flaring.",
"For a penalty on the body like a facemask it can just be trying to grab their shoulder and missing. So in that instance it is just a case of things happening too fast. Remember, you may be one of the top linebackers in the sport but you're also playing against the best running backs and receivers in the sport. \n\nFor something like holding you can see players trying to get away with it sometimes and it can depend on what the ref is letting them get away with. \n\nFor timing penalties (i.e. false start) there are a lot of mind games that happen when both sides line up. Quarter backs will use fake counts to try to get defenders to move early and defenders will fidget to try and get the offensive line to move early. ",
"It's tough to speak to each individual occurrence. But for every penalty that does get noticed, there's many more that go unnoticed.\n\nFace masking isn't the best example of this, more often than not, if you're going to face mask someone, you're going to get caught.\n\nHolding, however, is a much easier point to prove. The risk of getting caught holding is quite low, and the reward is quite high. If every hold got called in football, there would probably be a penalty on every play. It doesn't however, so players are generally willing to risk it.",
"You've gotten some good answers but I'll add a twist to them. If you're an offensive lineman and you get blitzed. You can see the middle linebacker coming at you at full speed while you're engaged with a defensive lineman. You try and block him but he's also strong and skilled - and he has speed on his side.\n\nYour choices are:\n\n1) Put up a token resistance you know he'll blow through where he will likely sack the ever loving fuck out of your QB.\n\n2) Throw your arm out and grab what you can.\n\nIn the first scenario you are risking a turnover and injury to your QB. As we've seen with Dallas this year, injuries to QB's are a bad thing.\n\nIn the second scenario there is a small chance the hold won't get seen. The refs are good but there is a lot going on so sometimes shit goes unnoticed. Assuming you are flagged though you have at least protected the QB and the ball. Coaches in general will take a 10 yard penalty over risking injury to the most important player.",
"* stopping someone with a penalty is often better than not stopping them at all\n* not all penalties are caught, and athletes often try to get away with as much as they can\n* intimidating an opponent might make them second guess the next play\n* keeping your balance, avoiding blockers, and tackling someone trying to escape, there is a lot going on there, and sometimes you are not aware of everything you are doing until it is too late"
]
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[],
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|
3a810t
|
how bulletproof are dinosaurs?
|
I just saw Jurassic World, and in the movie, (very mild spoiler alert) the Indominus Rex seems pretty impervious to normal rifles, a helicopter-mounted minigun, and she even shrugs off a pretty much direct hit from a rocket launcher thing. I know that, within the movie's logic, she was made to be the strongest, largest, toughest, etc. dinosaur, but I was just wondering how various real dinosaurs would fare against firearms.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3a810t/eli5_how_bulletproof_are_dinosaurs/
|
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"Dinosaurs don't have magic anti-bullet properties, and bullets aren't magical things that do abstract \"damage\" like in movies and video games. Bullets punch holes in things. That's it. Large animals have more blood to lose, more muscle to draw on in emergencies, and more flesh to pierce before irreversible damage is caused. Thus, to take down a large animal, you need to punch a *lot* of holes, or one very big hole. There are special guns and ammunition necessary to take down elephants. [Here is one side-by-side with an AR-15/M4/M16 combat rifle cartrige](_URL_0_). Thrice the width, and probably 30 or 40 times the charge. ",
"Well, how does a bullet kill a person? It either damages an organ so badly that it can't work anymore, or it hits a big enough blood vessel that the person bleeds out.\n\nSo when you look at the I-Rex, it's basically a huge, scaly mass of muscle. Most bullets probably can't get through all of that dense muscle to actually hit a major organ. Its blood vessels are probably large and there are probably lots of them; a bullet hitting some of the smaller, outer ones isn't going to get him to bleed to death. And it's not like a bullet can hit his aorta or anything, because that's in the center of a heavily muscled, bony, scaled body.\n\nSo it's sort of like shooting toothpicks at a human. Sure, they'll hurt, and if you get hit with enough of them in the leg, it might be tougher to move your leg. But they aren't going through and causing major damage that could really hurt the I-Rex.",
"Scroll over for TLDR. To see how this answer comes about, I would advise skipping over the spoiler: [Spoiler](/s \"We can't say for sure, but if we scale up based on an elephant, the minigun on the A-10 Warthog is enough to take it down with one bullet. It would likely stand up to a few rounds of something like a helicopter based minigun though.\")\n\nThis is actually a fairly complex question when you get down to it. While we can't be sure exactly all of the properties of dinosaurs, we can make some comparisons to modern animals. For example, many animals have very tough skin to deter predators, skin which can repel small arms fire. \n\nWhile bullet placement is the most important factor in bringing something down, the energy conveyed by a bullet is a good way to see if your gun is adequate to certain game. Squirrels and the like are fine with around 300 ft-lb of energy. Meanwhile, deer need around 1000 ft-lb of energy. Once you start getting to thicker skinned, more dangerous prey, you want at least 4000 ft-lb for something like a buffalo, and 5,000+ for an elephant. \n\nSo, if we apply this to the dinosaur in the movie (judging by the information of the J-park wiki), it looks to be about 50% larger than a t-rex. A principle known as the [square cubed law](_URL_1_). Means that this would put it about about 3.4 times the mass of the t-rex (7.5 short tons (I can't be bothered to convert units)). Scaling up the bullet energy puts a comfortable range of over 140,000 ft-lb of energy! Coincidentally, this is almost exactly the energy of a bullet from the A-10 Warthog, which has the power to punch through an inch+ of steel. And does [this](_URL_0_).\n\n"
]
}
|
[] |
[] |
[
[
"http://mythes-et-realites-sur-les-armes.blogvie.com/files/600-nitro-copie.jpg"
],
[],
[
"https://youtu.be/DaZ5stbVAlk?t=25s",
"https://en.wikipedia.org/wiki/Square-cube_law"
]
] |
|
jg52o
|
Is there any evidence that over the counter vitamin D supplements enhance mood?
|
I'm based in Melbourne, Australia. It's been a pretty miserable winter down here and basically everyone I know is at the pointy end of season affective disorder.
I know that they're probably not as effective as maintaining healthy dietary and exercise routines, but could these pills do anything more significant that the placebo effect, or do they just make for expensive urine?
|
askscience
|
http://www.reddit.com/r/askscience/comments/jg52o/is_there_any_evidence_that_over_the_counter/
|
{
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"c2btt5z",
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"score": [
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3
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"text": [
"In the unlikely chance that reduced sun exposure causes a severe Vitamin D deficiency, [you can experience depression](_URL_0_). However, taking supplements to prevent depression isn't quite established.",
"In the unlikely chance that reduced sun exposure causes a severe Vitamin D deficiency, [you can experience depression](_URL_0_). However, taking supplements to prevent depression isn't quite established."
]
}
|
[] |
[] |
[
[
"http://www.reuters.com/article/2010/05/12/us-vitamin-d-idUSTRE64B5OQ20100512"
],
[
"http://www.reuters.com/article/2010/05/12/us-vitamin-d-idUSTRE64B5OQ20100512"
]
] |
|
4u32z6
|
rules about reasonable suspicion vs. probable cause/just cause
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4u32z6/eli5_rules_about_reasonable_suspicion_vs_probable/
|
{
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"text": [
"Cop here:\n\nReasonable Suspicion:\n\nAn officer reasonably belives a crime *may have* occurred.\n\nFor example: An officer is patrolling an area where car break-ins have been a problem. He sees a man in a hoodie (even though it's warm outside) looking into a car window.\n\nHe has reasonable suspicion a crime may be occurring. He can legally stop that man and hold him long enough to determine if a crime occurred or not.\n\nProbable Cause:\n\nA higher standard; an officer has reason to belive a crime probably occurred.\n\nSame example as before, but the officer finds several cars with broken windows, the man has broken glass on his jacket, and a wallet from one of the cars.\n\nReasonable Suspicion is the standard required for a stop or detainment. \n\nProbable cause is the standard for am arrest.\n\nThere is no \"just cause\" in the US legal system. \"Beyond a Reasonable Doubt\" is the standard needed to *convict* a person of a crime.\n\nAs for vehicle searches:\n\nAn officer needs probable cause to search a vehicle without your consent. The exception to this is what's called a \"Terry Frisk\" in which an officer may *frisk* (or pat down- not search) a person or the lungeable (easily-reachable) areas of a car for a weapon if the officer has reason to belive a person may be armed.\n\nThe smell of marijuana is probable cause. It seems to be a common belief that cops will fake smelling marijuana in order search a car. I've personally never seen this happen and I would doubt that it happens often at all.\n\nYou have the right to refuse a search if the search is consensual only.\n\n*Edit: fixed autocorrect error.",
"I'd like to hear about the rules and regulations governing searching someone's cell phone history if you know anything about that too. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
2eh8cc
|
what role does a director actually play in creating a movie and what are the signs of a poorly directed movie?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2eh8cc/eli5what_role_does_a_director_actually_play_in/
|
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"The director is the head honcho of the movie set. What ever you see on the screen is because of what the direct wants you to see.\n\nThe director has the power the take the saddest script and redirect it to be the happiest thing you've seen.\n\n\nThe director is the conductor on the emotional train we call cinema.\n\nWithout the direct there is no vision and with no vision there is no movie. \n\n",
"The Director of a film (or a play, or a television show episode) is the person responsible for the creative vision of the piece. They create a concept from the script (which may or may not be something concretely found in the script, it may be metaphorical or tangential) and from the concept lead the design and production team towards a collaborative vision. Once rehearsals/filming have begin, the director blocks the piece (i.e. tells actors where to move), provides objective and subtextual support to the actors (i.e. tells them why they are saying the things the writer wrote) and ensures that the visual style and setting are within the original vision or concept parameters.\n\nIn film, they also work closely with the DP, first story-boarding the script, and then, once on set, making sure that each shoot is framed, blocked and shot per their vision. Including ALL design aspects, from the color of the walls to the type of purse a character might wear.\n\nIn essence they are the Captain of the ship. A lot of my notes below can also be laid at the feet of bad writing, but in film (less so TV and theatre) directors have a great deal of oversight on the writing, so they are typically held accountable if the writing is terrible.\n\nA film which has been directed badly will usually (but not always, the problem with a collaborative art form, which is what film is, is that there are many, many chefs in the kitchen. However, since the director tends to get the credit when everything works, they also tend to get the blame when it doesn't)--usually show the following flaws:\n\n1. Incoherent story telling. You don't know what is happening. Or why it is happening. Or who it is happening to. Sometimes things are just blatantly implausible.\n\n2. Cliche or trope ridden dialogue/shots/events. You feel like you've seen all of these things before. All the characters are stereotypes, all the plot points unfailingly predictable. Note: cliches, tropes and stereotypes can all be used well. But bad directors tend not to.\n\n3. Bad dialogue. Dialogue that is forced and unnatural. Dialogue that is too on-the-nose. People telling other people things instead of doing things. People explaining how they feel ad nauseam. Dialogue spoken only to allow for the plot to push forward, leading us to:\n\n4. Coincidental plotting, or plots hole you could drive a freight train through (not the small inconsistencies that almost every movie has, but HUGE giant massive oh-my-god-this-movie-is-broken plot holes). Coincidental plotting is when everything that has to happen for the plot to move forward does, without any effort on the part of the hero (or the bad guy).\n\n5. Bad acting. Directors are responsible for getting a performance out of their actors, so even if the actor can't act (one reason why casting is important) the director is still the one people are going to hold responsible for any painful moments on screen (this is less true in TV and theatre). \n\n6. Over or under designed. Over designed is when the concept/vision of the piece becomes more important then any other element. Think 300: Rise of an Empire or Sin City: A Dame to Kill For (not-at-all-oddly, both Frank Miller graphic novel adaptations, where the look was where the design team started with). Tim Burton is also a well-known director who can go to far with his vision/design to the point of over balancing the movie. Under designing is when there is a lack of design and the production feels (usually) cheap or not-thought-through. Good design elevates the narrative, supports the characters and provides visual clues to the audience about what is happening--excellent design can comment on and complement the action, enhancing the entire experience.\n\n7. Movies/TV only: bad editing. Either because there were technical difficulties during filming and the needed shots weren't gotten (or a director wasn't prepared and didn't get the shots they needed), and therefore the editor is attempting to make up for missing and/or bad shots; or because the editing itself is just bad. Odd cuts, odd shots going back to back, odd audio issues. Various other things. While most early directors at a studio on a movie won't have any say over the final cut, most editing issues are from a lack of footage (which is the director's issue), not bad editing. OR a director who does have final cut approval and shouldn't, which is where you got a three-hour movie that should have been 2 hours and 10 minutes max.\n\n8. Poor production value. An overall feel that the movie wasn't cared for (this isn't about money, this is about time and support). Usually shows in bad lighting, bad audio, bad set dressing, bad costumes--just an overall sense that these things weren't considered important or there wasn't time to pay attention to them.\n\nA film, tv show or theatrical play is an immense, multi-part beast, and the Director is the one that tries to tame it. To varying degrees of success. Every director probably has one (or many) bad movies to their name, as its how we all learn. The more telling test is not if they directed a bad movie, but if people wanted to work with them again. And, sometimes, the love of the thing they are creating can shine through the worst movie and make it, somehow, good (think Sam Raimi's original Evil Dead).\n\nHope that helped!",
"The actors portray characters in the story. The costumers and set decorators are illustrators to the story. The director is the storyteller.\n\nA character has a motivation or goal, the director advises the actor how to show the goal as part of the story.\n\nEvery good story relies on drama. Drama comes from conflict. Conflict in a traditional sense is \"the hero wants to do something and the villain wants to stop him\". Better conflict makes better drama, the best way is to make the villain stronger than the hero. So, the hero is trying to win something, but the villain is stronger than the hero and is trying to stop the hero. \n\nA really good storyteller is good with \"power inversion\", turning the power structure upside-down. How does the hero change himself, so he can overcome the more powerful villain?\n\n",
"The director also sets the tone on set -- the entire cast and crew follow his/her lead. The really great directors I've worked with [14 years in film/tv] came in prepared (knowing what they need to get) confident (by trusting the individual department heads but unafraid to kick a little ass if specific departments need the prodding) and decisive (each department hangs on the director's answers so the best directors have answers quickly and definitively).\n\nThe director should have the entire finished product in his/her head so the rest of the crew doesn't have to wait on his/her process.\n\n",
"/u/daijobu16 provided a very good answer, but I think I can simplify it a bit.\n\nOf the people involved in the creation of a movie, you have two job titles that can be said to be \"in charge\". First, the producers. A \"producer\" is often the money-man, and the person running the whole thing, including hiring the director, marketing the movie, getting it into theaters, etc.\n\nHowever, the role of a \"producer\" can be a little vague. People can get \"producer\" credits for all kinds of things related to the creation of the movie. For example, if it's a small movie, and you allow them to shoot some scenes in your house, they may give you a \"co-producer\" credit as a form of payment.\n\nSo speaking vaguely, the producer is the business-man in charge, but the director is the creative person in charge. He actually makes the movie. He oversees script re-writing, casts the movie, oversees shooting, oversees editing.\n\nWhat he does exactly can vary from movie to movie, and different directors have different preferences. Some directors exercise more control over every individual shot, while others give their cinematographer and camera man more leeway. Some directors tell the actors exactly what they want the actor to do, while others make it more of a collaborative process. Some directors edit their own movies, while others will work with editors and allow those editors some freedom. However, it's the director's job to oversee the whole process.\n\nSo the role isn't set in stone, and each director finds what fits for them, but most of the time, directors will cast all the major roles, tell actors what kind of performance they want, choose a lot of the shots and decide how things should be lit, and provide a lot of guidance to the editors.\n\nSo if anything in the movie sucks, it's the director's fault to some degree. The script might be lacking. The actors might have sucked. The editor might have butchered the edit. The camera man might have shot something with poor focus. But the director was supposed to be overseeing it all, so the director is still at fault, at least to some degree. The only thing that's kind of outside of his control is meddling from the producer (or studio or whatever)."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
adgdc8
|
What sources are there to suggest that Nero blamed the fire in Rome in 64 CE on Christians? Do we know how he became aware of the movement? Would these suggestions be the earliest independent recognition of Christians as a distinct group in the historical record?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/adgdc8/what_sources_are_there_to_suggest_that_nero/
|
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"The only source that mentions Nero's blaming of the Christians is Tacitus ([Annals 15.44](_URL_2_)):\n\n > Therefore, to scotch the rumour, Nero substituted as culprits, and punished with the utmost refinements of cruelty, a class of men, loathed for their vices, whom the crowd styled Christians. Christus, the founder of the name, had undergone the death penalty in the reign of Tiberius, by sentence of the procurator Pontius Pilatus, and the pernicious superstition was checked for a moment, only to break out once more, not merely in Judaea, the home of the disease, but in the capital itself, where all things horrible or shameful in the world collect and find a vogue. First, then, the confessed members of the sect were arrested; next, on their disclosures, vast numbers were convicted, not so much on the count of arson as for hatred of the human race. And derision accompanied their end: they were covered with wild beasts' skins and torn to death by dogs; or they were fastened on crosses, and, when daylight failed were burned to serve as lamps by night. Nero had offered his Gardens for the spectacle, and gave an exhibition in his Circus, mixing with the crowd in the habit of a charioteer, or mounted on his car. Hence, in spite of a guilt which had earned the most exemplary punishment, there arose a sentiment of pity, due to the impression that they were being sacrificed not for the welfare of the state but to the ferocity of a single man. \n\nThe passage has caused a great deal of scholarly discussion over the years, including some doubts over its authenticity. However, the general consensus is that this is a genuine bit of Tacitus, and yes, that makes this pretty much the earliest mention of Christians as a distinct group by a non-Christian author. Suetonius and Pliny the Younger also mention the Christians, and both were writing in the early 2nd century, so the same time as Tacitus. In both of these writers, the Christians are also coming in for rough treatment by the Roman authorities - in [Suetonius](_URL_3_) it's Nero again (and maybe [Claudius](_URL_1_) a decade earlier), and in Pliny it's actually [himself](_URL_0_). He was the governor of the province of Bithynia, and oversaw the trials of some Christians. His letter describing his actions to the Emperor Trajan is a fascinating window into the interactions between the Roman state and the new religious group, which is less than a century old at this point, and probably only numbers a few thousand adherents across the whole empire. The crucial difference between the writers here is that Tacitus and Suetonius are describing events around 50 years before their time, whereas Pliny is talking about his own experience. How much does the contemporary situation colour the accounts of Tacitus and Suetonius, in terms of their awareness of Christianity as a distinct group? There's also genre and authorial intent to consider here, especially with Tacitus. It's always important to remember that throughout his *Annals,* Tacitus is intentionally presenting a gloomy, degenerate picture of Rome, fallen from its glorious past. His portrayal of Neronian Rome is a centrepiece to this, and we can't take the tiny passage about the Christians out of this context. Tacitus lumps Christianity in with the other horrible and shameful things that have collected in Rome under the emperors, but makes it pale in comparison with the cruel debauchery of Nero, who allegedly burned the Eternal City to satisfy his own desires and then tortured innocent people to cover his tracks.\n\nAs to how Nero became aware of Christianity, we can only speculate. Tacitus implies they were notorious in the city, and the evidence from the New Testament suggests a fairly strong community. Paul wrote his letter to the Christians in the city before he visited, and preached there for two years while awaiting trial. Perhaps someone in the imperial household (or even Nero himself) picked up gossip or rumour of these new beliefs, or maybe heard someone preaching on the streets. Pliny's letter suggests that perhaps the emperors might have also been getting news about the religion from other provinces, especially when Christians were caught up in (or the cause of) civil unrest. "
]
}
|
[] |
[] |
[
[
"http://faculty.georgetown.edu/jod/texts/pliny.html",
"http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Suetonius/12Caesars/Claudius*.html#ref75",
"http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Tacitus/Annals/15B*.html",
"http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Suetonius/12Caesars/Nero*.html#16"
]
] |
||
3y4ilm
|
why do so many great mma fighters have multiple losses on their record compared to boxers?
|
It seems to me that the truly great MMA fighters tend to have multiple/more losses on their records when compared to boxers, where the truly great ones tend to have none or one or two defeats only.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3y4ilm/eli5why_do_so_many_great_mma_fighters_have/
|
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"There's more ways to lose in mma. Boxing is more technical and skill makes a bigger difference than blind luck. Also, politics. Most boxers with only a few losses compared to wins have some very questionable decisions in their favor",
"Part of it is the infrastructure of the sport. UFC is now head and shoulders above any other MMA promoter, so they got most of the best fighters and make them fight each other. In boxing, there are 4 organizations giving out belts, and each fighter has his own promoter. Boxing matchups become business decisions instead of \"what's best for the sport\" decisions, because so many people want a piece of the pie. The UFC has control over it's own pie because the fighters need to come to them to compete against the best",
"A couple of reasons:\n\n1) MMA is more physically tolling on the body. Even in training, you get hit, get slammed and get submissions put on you. More parts of the body are involved so there are more places to get injured. You are pretty much safe below the belt in boxing and don't have to worry about falling unless you get knocked out. You have to worry about both of these things in MMA.\n\n2) It depends on who you consider \"a great\" and when you consider them one. Anderson Silva didn't lose between 2007-2012. Fedor didn't truly lose from 2000-2009. GSP only lost twice from 2002-2013. Fedor's now lost multiple times, but it doesn't make his original run any less.\n\n3) With UFC being the only real show in town right now and MMA matchups being booked by a company, and not individual promoters, it's hard to duck and dodge the best competition like boxers do. Boxers don't really have to face anyone they don't want as it's more on individual drawing power, while UFC is a full company. UFC will be around if say Rhonda Rousey leaves. Random boxing promoter may not be if his man leaves.\n\n4) UFC and MMA have a lot less weight classes than boxing. There are 17 boxing weight classes right now. UFC has 8. That means the better talent is less spread out and you have a lesser chance of getting by on favorable matchups than skill.",
"Adding to other answers, MMA is also a relatively new sport and is constantly evolving. It is difficult to stay at the top for a long time when new fighters come along with different skills, and training built on the experience of others.",
"Short and indirect answer: There are far more boxers, historically but also today, than MMA fighters. \n\nDetailed answer: More competitors means more chances to pile up easy wins. Almost every famous boxer has not just a good record, but a lopsided record. *Ring* magazine's [top 10 pound-for-pound boxers](_URL_1_) are a combined 333-9-7. \n\nThat's because they all spent their early years fighting grossly outclassed boxers who probably ended up quitting shortly thereafter. \n\nTake the top boxer in the world, 44-0 [Roman Gonzalez.](_URL_0_) Here are the career records of the first few guys he faced, in chronological order: \n\n* 0-6-1\n* 1-7\n* 0-3\n* 14-12-2\n* 3-13\n* 9-17\n* 5-23-3\n* 5-23-3 (same guy)\n\nYou get the idea. If there were fewer boxers - i.e., if the bottom level of boxers didn't exist - the great ones' records wouldn't be so lopsided.",
"Can't duck talented fighters when you're the champ. Also there's many ways to win a fight and no one fighter is the best at wrestling, judo, jiu jutsu, kickboxing, boxing, sambo etc etc. Anyone can get caught by a superman punch or armbar, no one stays on top forever. It's understood that you don't have to be undefeated to be an excellent fighter. \n\nAlso no high level MMA organization gets away with putting tomato cans against top fighters. Top ranked fighters generally fight top ranked fighters, it's rare to see top 10 fighters against loosing record nobodies. A popular up & coming fighter may rack up several easy wins on the amatuer or C list shows but A list organizations have little reason to prop up a fighter. The best fights are battles, not one fighter outclassing another all fight. "
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[
"http://boxrec.com/boxer/319725",
"http://ringtv.craveonline.com/ratings/pound-for-pound"
],
[]
] |
|
3l6371
|
How come soldiers in Mesoamerica and Japan didn't make widespread use of larger shields like in Eurasia?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3l6371/how_come_soldiers_in_mesoamerica_and_japan_didnt/
|
{
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"Define large.\n\nIn Mesoamerica, different shield designs were used at various points in time. Ross Hassig talks about changes in Mesoamerican shield design in his book *War and Society in Ancient Mesoamerica*. \n\nThe Central Mexican city of Teotihuacan, which fell some 500 years before the Aztec empire arose, appears to have used rectangular shields. The most famous depiction of these can be found on the Teotihuacano soldiers depicted in [Tikal Stela 31](_URL_1_). Given the way this shield is carried, it appears to have been made out of a flexible material and was likely more useful for deflecting glancing blows from projectiles rather than for melee combat. Because the material was likely flexible, it wouldn't have been practical to make them very large. Maya warriors during the Classic period were rarely depicted with shields. Those depictions that do exist typically show small rounded bucklers that are even smaller than these. A comparison of these two types of shields can be seen [in this image](_URL_0_). (With a caveat, the labels in that image are inaccurate, the different shield types correspond to regional differences not class distinctions). In contrast to the rectangular shields, the rounded shields appear to be rigid (likely made of wood), and were likely designed to deflect blows from clubs.\n\nThe rounded shield that you see in [most depictions of Aztec soldiers](_URL_2_) was largely prominent during the Postclassic period (c. 900 AD to conquest). This shield design appears to gain prominence in Mesoamerican armies about the same time as the macuahuitl, a sword-like weapon made of wood and obsidian. The rigid portion of this shield was as large, if not larger, than the metal shields carried by the conquistadors. However, as you can see in the image, it also had a feather fringe on the outside that, like the flexible shields used by Classic Period Central Mexican soldiers, was likely designed to deflect glancing blows from projectiles. If the fringe is considered part of the shield, they were actually quite large.\n\nWhat you're probably asking though is why they didn't develop the large tower shields like the kinds you frequently see in movies depicting Roman legions. I can only speculate, but it's likely that those kinds of shields were designed for a different kind of combat. As Hassig explains (and as I've tried to explain above), Mesoamerican shields were typically designed to either deflect indirect hits from projectiles and/or for hand-to-hand combat between individual combatants. Tight formations of spearmen (like a *phalanx*) were not frequently employed in most Mesoamerican armies (with the possible exception of some Central Mexican armies during the Classic Period). If the old adage that \"form follows function\" holds true, it could be that such a design simply wasn't necessary given the tactics used by Mesoamerican armies. It's also possible that such a shield design would not be as effective with materials other than iron, which the Mesoamericans did not have.",
"I've written a brief outline as to why the Japanese didn't use shields in [this comment](_URL_0_)."
]
}
|
[] |
[] |
[
[
"http://i.imgur.com/3gtNF6M.jpg",
"http://i.imgur.com/M9SBeyK.gif",
"http://i.imgur.com/z5pYc3j.jpg"
],
[
"https://www.reddit.com/r/AskHistorians/comments/3jqhzx/why_arent_shields_prevalent_in_feudal_japanese/curjcab?context=3"
]
] |
||
1q3khx
|
why, as an adult, i take the same amount of cough syrup or other medicines as a 12 year old when i am heavier and more physically mature?
|
I was just wondering this, does it have to do with decreasing returns? I just found it funny that a 12 year old who weighs around 45 kilos takes the same amount of cough syrup or panadol as an adult male who usually weighs upwards of 65 kilos, and physically has completed growing and developing (this may or may not have anything to do with it).
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1q3khx/eli5_why_as_an_adult_i_take_the_same_amount_of/
|
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],
"text": [
"The dosage is just what they know is safe but still effective generally. If you feel like the recommended dosage is insufficient you can go above. Of course if something goes wrong you can't sue the company because you went against recommendations, and you didn't hear it from me that it should be safe, but for the very reason of lawsuits the recommended dosage is already a bit conservative. ",
"Coating-action aside, some medication dosage is tied to metabolic activity rather than body weight. When a kid's body is mature enough to fully metabolize medication, they're ready for the adult dose. In between age 12 or so and geriatric age, and barring some factor like liver disease, one's ability to metabolize meds doesn't change much even though your weight might. Caveat & disclaimer: I'm not a health professional-- this is just paraphrasing what my kid's pediatrician told us. ",
"As an adult you could always, you know, just take more than instructed. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
1aq961
|
Did WW2 had any cultural impact on arts or music in Europe?
|
I know that Shostakovich (an composer) was somewhat affected by it and some of his works reflect it. But were there others that made art/music that was inspired by the war?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1aq961/did_ww2_had_any_cultural_impact_on_arts_or_music/
|
{
"a_id": [
"c8zt6gb"
],
"score": [
4
],
"text": [
"Huge, post modernism was in part a reaction to the world wars and the changes they brought. \n\nIn Europe the grief was palpable, imagine if 20% of your population died. It made many artists think that any attempt at meaning or beauty was hopeless and futile in the face of such horror. \n\nIt was really shattering to many Europeans that their great and respectable culture, where people where supposed to be civilized and intellectual had produced such immense hatred, death and destruction. \n\nI think Theodor Adorno summed up the feeling best, \n\n > To write poetry after Auschwitz is barbaric."
]
}
|
[] |
[] |
[
[]
] |
|
21vj3f
|
When and why did golf become the default "upper-class hangout/dealmaking" activity? What filled that role before?
|
So I've heard that learning to golf is kind of a requirement for certain executive schmoozing/marketing jobs, so I was wondering if you guys could fill me in on why and when it became normal for executives, politicians, and other powerful people to play golf while chatting about deals and other such things.
What did they do before golf was popular? I'm guessing riding horses or somesuch, but if someone actually informed could step in, I'd appreciate it.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/21vj3f/when_and_why_did_golf_become_the_default/
|
{
"a_id": [
"cggymzn",
"cgh4yrq",
"cgh6sfn",
"cgh9i54"
],
"score": [
291,
11,
8,
7
],
"text": [
"In ancient Persia, there was quite an exciting sport that we've been able to reconstruct from artistic depictions, and also the preserved fragments from the ancient Persian *On the art of entertaining officials*, an important handbook for satraps and other royal officials. Whenever a group of royal officials were seriously bored, they would first locate a cliff, or a mountain. They would also bring with them a large herd of camels, and then send down observers to the bottom of the mountain (this being pretty important for what followed). Each noble would then choose a camel. The camel would be strapped into a harness, and then attached to a large brightly coloured canvas. And when I say large, I mean several metres wingspan. Then the camels would, one by one, be forced to run off the edge of the mountain or cliff. They would quite literally hang-glide from there to the bottom, and the competition was won by noble whose camel travelled the greatest distance. Camel harnesses breaking was a big problem, which is why there were so many brought up the hill. It seems to have been a pretty obscure sport in the rest of Persia, all told, but nobles seem to have loved sending camels hang-gliding off cliffs.\n\nA reconstruction of the hang-gliders for camels can be found in Samuel P Langley's papers, currently stored in the Smithsonian Institution Archives; the man simply insisted on attempting to recreate one. A more recent and direct look at the subject can be found in Louis Nockton-Draffer's *The Persian Funeral Glider: Reconstruction and experiential perspectives*, presented at the 7th Experimental Archeology Conference in Cardiff\n\n[WARNING THIS IS TOTALLY A JOKE NONE OF THIS IS REAL. READ MOD NOTE HERE](_URL_0_)",
"I'm under the impression that hunting and fishing were the go-to outdoors activities for upper-class men prior to the 18th century or so. I'm not historian of sport, so I can't comment on this in any great detail, but the sheer number of hunting scenes that one sees in early modern art suggests something about the role that organized hunting played in the social and cultural lives of the aristocrats who were the patrons of the arts. \n\nAlso, it's my understanding that until the later 19th century, golf was not widely-known or widely-played outside it's land of origin, Scotland. I would speculate that the rise in popularity of golf might be somehow related to the well-documented \"Celtic Revival\" cultural movements of 19th-century Britain, that saw a romantiscation of the lives and histories of previously-marginal peoples of the peripheries of the Britain -- it is this period that gives us the modern conceptions of King Arthur, Welsh bards, and Scottish Highlanders (complete with kilts and claymores).",
"Some people seem to misunderstand the question, so I'll clarify. I mean that today, if some executives want to talk about a deal in an informal setting, get to know other executives, or network while doing something, that \"something\" will often be golf.\n\nI am not asking why poor people don't also golf, because the land requirements obviously make it hard for non-rich to have a golf course.\n\nI am asking why the rich use THIS as a hangout activity, instead of, say, tennis or poker.\n\nI mean they can do that too, but golf seems to have become the main hangout activity to the point where it's nearly required to have golf skills to be an executive.\n\nAlso seems to have permeated military officer's culture, [if this recent news article on military golf courses](_URL_0_) is any indication.",
"In the UK Golf is not an upper class thin but rather a lower middle class pastime. Quite often local business life was organised around the golf club, which was normally quite a modest affair. That is not to say that rich people do not play Golf, the Duke of Devon is a fanatical golfer but the amount of people that play in the established middle classes is nearly nil. How it became an exclusively hoighty-toighty affair in the USA I have no idea. \n\nAs for what powerful people did before, hunting was the thing. Nothing like blasting grouse or pheasant all over the place with a blunderbuss and then going back to a country house and getting plastered and then going out and doing it again the next day. Boar as well, before the aristocracy hunted them to extinction, and hawking which was a more ladylike pastime which women could take part in. \n\nThere were of course other things like the Reform club, literary salons, and just informal gatherings at peoples houses."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/AskHistorians/comments/21yyci/important_message_re_source_reliability/"
],
[],
[
"http://www.motherjones.com/politics/2014/01/pentagon-military-golf-courses-map"
],
[]
] |
|
204kws
|
When Canada changed its flag, what did they do with all the old ones?
|
Be they stitched into uniforms or flown from flagpoles, Canada must have had a lot of old flags. How did they get rid of them? Were they disposed of respectfully, or were the majority just thrown out?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/204kws/when_canada_changed_its_flag_what_did_they_do/
|
{
"a_id": [
"cfzzfrw"
],
"score": [
8
],
"text": [
"There's never been any legislation covering flag disposal in Canada. The rules of Flag Etiquette are laid out in a [publication by the Department of Canadian Heritage](_URL_0_) and the rule for disposal is pretty vague. It just says that old flags \"should be destroyed in a dignified way.\" But of course that's just the rule as it stands today. The [Flags of the World website](_URL_1_) suggests that this regulation didn't exist until the 1970s or 1980s, well after the 1965 switchover. In the Navy, for example, old ensigns were often turned into polishing rags. Not quite the respectful disposal one might expect.\n\nOn top of there being no general rule for flag disposal at the time, there were no specific instructions for the flags that got lowered in 15 Feb 1965 (at least none that were made public that I'm aware of). Given all that, I don't think we can really say what happened to all the old Red Ensigns. I do know that the last Red Ensign flown over Parliament is currently in the collection of the Canadain Musuem of History though. You can see a picture of it if you [scroll down this page here](_URL_2_).\n"
]
}
|
[] |
[] |
[
[
"http://www.pch.gc.ca/eng/1359048153800/1359048247377",
"http://www.crwflags.com/fotw/flags/ca_prtcl.html",
"http://www.historymuseum.ca/myhistorymuseum/stories-and-objects/"
]
] |
|
4g0vkh
|
if gravity is actually the earth accelerating upwards and the earth is spherical, how can it accelerate upwards in all its surface?
|
As explained here _URL_0_
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4g0vkh/eli5_if_gravity_is_actually_the_earth/
|
{
"a_id": [
"d2dnwy2"
],
"score": [
9
],
"text": [
"Did you get the bit where it mentioned frames of reference? Because that's what this is all about.\n\nNow, ignore the planet. Ignore all the big stuff around here. Ignore me, ignore you. We're going to talk about two tennis balls in deep space. They're just there, in space - they're not sitting on a table, they're not sitting on the ground. They're just there.\n\nNow, they're getting closer to each other. So, is it correct to say that:\n\n1. Ball A is moving towards B? \n1. Ball B is moving towards A? \n1. Both balls are moving towards each other?\n\nWell, it could be any of them. It depends on what you define as your frame of reference.\n\nIf you **decide** that B is stationary, then case 1 applies. If you decide that A is stationary, case 2 applies. If you decide that an invisible point in the middle of the two is stationary, 3 applies.\n\nThe thing is, we tend to think of the Earth as the be-all and end-all. It's big, it's kinda constant for most of us - it just sits there under our feet, not seeming to move.\n\nBut... what about the tennis ball example? We can decide which thing moves. If I hold a tennis ball above the Earth and let go, the same thing applies. I can **decide** whether the ball moves, the Earth moves, or both."
]
}
|
[] |
[
"https://youtu.be/NblR01hHK6U"
] |
[
[]
] |
|
dwmt46
|
what the hell did people think sports concussions were before?
|
Over the last 15-20 years we’ve seen professional sports crack down on concussion safety, mainly the NFL, but it’s also been a issue with pro-wrestling, and boxing.
I understand that CTE has been discovered and can only be officially diagnosed after an autopsy.
HOWEVER, what the hell did people think concussions were before? I cannot understand how any brain injury could be seen as anything less than critical.
We’ve had the term “brain damage” forever. I just don’t see how people are just now understanding that a brain injury is always serious.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/dwmt46/eli5_what_the_hell_did_people_think_sports/
|
{
"a_id": [
"f7k9zt0",
"f7ka48g"
],
"score": [
14,
6
],
"text": [
"Well the expression for a concussion was usually something like \"he got his bell rung\" to explain the immediate symptoms of concussion. CTE is different that a concussion though. It is caused by many concussions over time, slowly building, as we understand it now, but is often seen later in life.\n\nSo a normal guy racks up a few concussions and recovers. Then 20 years later he has real mental health problems. There was no way for them to link it to the bell ringings he got in high school football. \n\nBasically they didnt realize these impacts and symptoms which would subside fairly quickly were having permenant impact on the brain.",
"It was hard to see the long term effects at first. You get \"your bell rung\" or concussion and you're fine a few days later and everything seems to have healed and you get back to it. It's only decades later that people start getting more aggressive and impulsive as a result of CTE. Might've been hard to connect the dots at first. I'm sure the NFL did their part to not release any information they had about the dangers of repeated concussions as well"
]
}
|
[] |
[] |
[
[],
[]
] |
|
afayf9
|
the brain is very important, and very complex and exists in a confined space; given that why is it that tumors in the brain are able to get so large before being noticed?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/afayf9/eli5_the_brain_is_very_important_and_very_complex/
|
{
"a_id": [
"edx2v7r"
],
"score": [
6
],
"text": [
"The common symptoms of brain tumors are just that, common. Headaches, nausea, dizziness, and so on can be caused by a lot of other things and the symptoms themselves can come and go. It's usually once more serious symptoms appear or a pattern of symptoms is recognized that a patient undergo MRI."
]
}
|
[] |
[] |
[
[]
] |
||
2bjpmg
|
Can anyone tell me about a specific American flag?
|
I recently went to the Charleston Museum. They have [an American flag that they don't really know anything about](_URL_0_).
I realize this is a long shot because a museum should have ample resources to figure out what something is. But I'm curious to see if anyone here can give me some information about this flag.
The flag has 5 stripes with red on the top and bottom. It has 23 stars, which should out it around 1820-1823. The flag was donated in 1923.
I included a picture of the information card next to the flag.
And don't worry, the museum asked photography and I didn't use my flash.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2bjpmg/can_anyone_tell_me_about_a_specific_american_flag/
|
{
"a_id": [
"cj66403"
],
"score": [
10
],
"text": [
"hi! it might be worth x-posting this question to the flag aficionados in /r/Vexillology"
]
}
|
[] |
[
"http://imgur.com/a/N4hro"
] |
[
[]
] |
|
11oyyv
|
openoffice vs. libreoffice (vs. microsoft office)
|
OpenOffice vs. LibreOffice: What's the Difference, why did they split, etc..
.
(OpenOffice or LibreOffice) vs. Microsoft Office: Is one better then the other; What are the limitations of each, or is it just personal preference.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/11oyyv/eli5_openoffice_vs_libreoffice_vs_microsoft_office/
|
{
"a_id": [
"c6oc4dg",
"c6ohmg6"
],
"score": [
6,
2
],
"text": [
"I haven't used OpenOffice since the split, nor MS Office since before then, so I can't comment on the differences between them today. But I can give a little background on the split itself. \n \nOpenOffice used to be run by Sun. [In 2009 Oracle bought Sun](_URL_0_) and maintenance of OpenOffice became less of a priority - basically Oracle put it on the back burner. LibreOffice was created by the community in response to that, and a number of old OpenOffice contributors now work on LibreOffice instead, and many of the financial backers of the project also followed. \n \nOracle later donated OpenOffice to Apache, so now both software suites exist, and the short version is that LibreOffice is the spiritual successor to OpenOffice, and the new OpenOffice is essentially a completely new entity.",
"OO vs LO:\n\nOO was made by Sun with a huge community to develop it. When Oracle bought Sun in 2009, a large segment of the sevelopers weren't fana of Oracles plans for OO. So they \"forked\" the project (copied the code, changed the name, and ran it as a seperate project; this is very common in the realm of open-source software) into LO. Oracle eventually donated OO to Apache, so at this point its really just personal preference.\n\nOO/LO vs. MSO\n\nWell, the main difference is MSO is closed-source, commercial software, while OO/LO are open-source. They both do the same thing but in different ways. OO/LO is also free while MSO costs money to buy."
]
}
|
[] |
[] |
[
[
"http://www.openlogic.com/wazi/bid/188115/LibreOffice-vs-OpenOffice-org-Showdown-for-Best-Open-Source-Office-Suite"
],
[]
] |
|
enpxss
|
- when you dent your car and the auto body shop uses filler to fill the dent, what are they using?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/enpxss/eli5_when_you_dent_your_car_and_the_auto_body/
|
{
"a_id": [
"fe48cho"
],
"score": [
3
],
"text": [
"Polyester resin/putty, sometimes mixed with fiberglass for extra strength. Bondo is a fairly common brand, and other brands are often referred to as \"bondo\" as a result."
]
}
|
[] |
[] |
[
[]
] |
|
716qta
|
is it pitch black in space or is there enough ambient light to see something held in front of you?
|
Assuming you're not in the vicinity of a star, of course. Somewhere like Voyager's position, 10 billion miles from earth, could you see your hands? Total darkness?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/716qta/eli5_is_it_pitch_black_in_space_or_is_there/
|
{
"a_id": [
"dn8itzu",
"dn8iwlc",
"dn8wy52",
"dn965y1"
],
"score": [
8,
73,
60,
4
],
"text": [
"Somewhere on the Internet NASA has a page describing how much light there is and what you can see. If I were there I would be sure I had a flashlight. Maybe I would sprinkle powder and shine the light on the powder to get a diffuse illumination. Or I could shine the light on a nearby surface to use the surface as an illumination source.\n\nIt really is pretty dark. I mean, think of a moonless night on Earth. It would be no brighter.",
"Light would be very dim.You would probably be able to make out objects at close range, but not read or see fine details.\n\n[Here's a good r/askscience post on the subject](_URL_0_)",
"In space, there's nothing. The only source of ambient light comes from stars. That means if you are inside the solar system and there isn't a planet in the way, you're gonna see very well. Things will be very bright on the side facing the sun, but shadowed on the other side.\n\nIf the sun is blocked, you will still receive light from other celestial bodies and the milky way, which will give you extremely dim vision. You will be able to see a little bit in front of you, but not enough to distinguish complex things.\n\nIf you leave the solar system, same thing, but even darker because celestial bodies like the moon or saturn will reflect a little bit of light, depending on where you are. So without those, it'll be pretty dark. Very difficult to recognize objects probably, but if someone waves something in your face you could see it (Especially since it'll block stars behind it from your vision). If you leave the milky way and hang out in between galaxies, it'll be even dimmer, so much that it's gonna be almost impossible to see anything.",
"Ask yourself, how dark is it on a new moon on earth in a place without artificial light? Like on a field in the middle of nowhere."
]
}
|
[] |
[] |
[
[],
[
"https://www.reddit.com/r/askscience/comments/1lky7h/how_dark_is_space/"
],
[],
[]
] |
|
9s31si
|
how do cinema projectors have such high quality compared to personal home projectors?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9s31si/eli5_how_do_cinema_projectors_have_such_high/
|
{
"a_id": [
"e8ln3x1",
"e8lne6m",
"e8lzq4r",
"e8m1lpv",
"e8m61xy",
"e8m7njo",
"e8mn12k"
],
"score": [
300,
10,
29,
7,
22,
8,
2
],
"text": [
"They got a light source (think: a bulb) that is consuming so much energy it's crazy compared to the tiny box you got in your own living room.\n\nAnd bulbs always create excess heat that needs to be cooled away with active cooling. i.e, fans. Fans are noisy.\n\nBut no-one in the cinema cares, because that projector is in it's own room, with a glass window. No-one in the audience hears the fan.",
"A big difference is that they use three display devices (DMD or LCOS) to make red/green/blue, so they don't need a rotating filter wheel. Better screens and lenses help too. It's like the difference between a cheap digital camera and a good DSLR and lens. ",
"It's the same like in every industry doing essentially the same like consumers do themselves.\n\nYou can buy a nice little light effect and it would be enough for you but a company which is earning their money by using lights has the money and the knowledge to buy a more professional product.\n\nThe projector you are using at home may cost around a thousand dollars, the projectors used by professionals cost much more that that. For that much money they get a better lamp, better optics and the ability to play movies that are stored in a way that is too expensive for the end consumer. Also they will use a much better screen, which makes a lot of difference.\n\nThey spend hours in calibrating the projector what wouldn't be worth for anyone showing some content for less that a couple thousand people.",
"Home projector pricing makes no sense. Projectors come down to 4 things:\n\nBrightness, typically measured in ANSI lumens. More is better, because it means the picture light is stronger than the ambiant light. Typical home projectors will be between 1500 - 3500 ANSI lumens. The outside advertising projector at my local cinema was 8000 ANSI... \n\nContrast, same as a TV. Best noticed displaying a black image. More is better.\n\nKeystone, vertical and horizontal are key for placing a projector. It let's you bend the image so you can offset the projector. As projectors can be 4m away a small offset causes a big picture tilt, keystone let's you fix that. \n\nDisplay technology. Optima like a lot of projector brands fire a white beam and encode a colour signal onto it. As the ambiant light increases this causes the much weaker colour signal to fade. Sony, Epson, etc.. have a multi beam technology. While named various things, it boils down to firing red, green and blue beams at the wall. Since there are coloured beams the image doesn't white out.\n\nNow why are home projectors poor? Because adoption is less so places sell projectors as a home theatre experience (thousands of pounds). Projectors aren't sold on their specifications but audiophile gimmicks. I have friends who spent £2k on an optima from richer sounds that was half the lumens, lower contrast and the same resolution as my £400 Epson projector.\n\nMy favourite gimmick 5 years ago was dlp (traditional bulb) vs led. Led had such a price premium that 5 years of daily use later I'm still financially better off by going dlp. \n\nBecause there isn't a clear specification war going on the market stagnated. It took Epson 5 years to make a projector better than my current one (eh tw 490 vs eh tw 650).\n\nAlthough something happened this year, market seems much saner, as I was going to post examples and failed to quickly find one.\n\nEdit - typos/clarity",
"Like everyone else has said, money. It's literally like the difference between a used Honda and a brand new Rolls Royce. A movie theater projector costs around $75k-$100k and 20,000-30,000 lumen,. Everything about it is precision made, calibrated, and maintained. You can get home theater projectors with DLP 3chip technology, 4k video, 5000 - 8000 lumens, and interchangeable lensing, but it still won't come close to the one at the theater.",
"Some have multiple lamps...some have extremely powerful lamps. Some have multiple extremely powerful lamps...that are maintained by professionals. Lenses are excellent, and the projectors have great ventilation keeping them dust free and cool. They also have specialized software optimally running them. They are also mounted at optimum distances/angles...and the screens are designed to be used with them, so they are very bright/clear. Also the files they play are high resolution, using specialized players/processors...that are connected to the projectors with digital cable (fiber/dual link dvi).",
"Cinema projectors have lamps that can output 20,000+ brightness measuring units (lumens). Home projectors do like 2,000."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[]
] |
||
2alzkt
|
why do chiggers and/or mosquitos seem to bite around a person's joints (e.g. ankle)
|
Why God?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2alzkt/eli5_why_do_chiggers_andor_mosquitos_seem_to_bite/
|
{
"a_id": [
"ciwhtll"
],
"score": [
3
],
"text": [
"In short, evolution or The Fall, depending on your religious flavor or lack thereof.\n\nThe most prominent reason is the fact that the blood vessels are very close to the surface of the skin over these areas. Mosquitos have the capacity to sense heat as well as (some speculate) the capacity to sense the blood pumping through blood vessels."
]
}
|
[] |
[] |
[
[]
] |
|
3c7poz
|
How exactly was Jefferson Davis elected President of the Confederacy?
|
According to his Wikipedia page, he was selected by delegates at a constitutional convention, but how were those men appointed? Was there any form of popular vote involved?
And as an aside, were Davis' powers and responsibilities relatively comparable to those of Lincoln, or was he limited by the looser structure of the Confederacy?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3c7poz/how_exactly_was_jefferson_davis_elected_president/
|
{
"a_id": [
"cst0fnt"
],
"score": [
9
],
"text": [
"While a perfectly fine question, more of our Civil War experts are sticking around in [this AMA thread today, so I would suggest you repost it here!](_URL_0_)"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/3c73kh/panel_ama_the_american_civil_war_era_military/"
]
] |
|
1ef2hf
|
What factors contribute to resting metabolic rate?
|
And how much variance is there really between individuals?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ef2hf/what_factors_contribute_to_resting_metabolic_rate/
|
{
"a_id": [
"c9zoh4n"
],
"score": [
2
],
"text": [
"First question; not my area\n\n\nSecond question, relating to the first:\n[Not much](_URL_0_)\n\n\n > One study noted that one standard deviation of variance for resting metabolic rate (how many calories are burnt by living) was 5-8%; meaning 1 standard deviation of the population (68%) was within 6-8% of the average metabolic rate. Extending this, 2 standard deviations of the population (96%) was within 10-16% of the population average.\n\nsources within top link\n\nIt's perhaps better to use Metabolic equivalent, using it to compare the instant valuation with the type of physical activity being done given that RMR within a given population doesn't vary greatly."
]
}
|
[] |
[] |
[
[
"http://examine.com/faq/does-metabolism-vary-between-two-people.html"
]
] |
|
kptcj
|
how is facebook exploiting me?
|
I keep reading it in memes and all over reddit. How? Thanks!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/kptcj/how_is_facebook_exploiting_me/
|
{
"a_id": [
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"Basically anything you submit to Facebook becomes their property; Pictures, personal information, everything.\n\nPeople complain about privacy and then go and spill every single detail of their life to Facebook, thus Facebook is \"exploiting\" idiots.",
"The whole premise of facebook is in the interests of exploiting the public.\n\nPeople who haven't stopped to think about it think that facebook is a service provided to the general public allowing us to connect electronically with the people in our lives. They think that this service is financed by the tiny ads on the margins.\n\nIn fact, facebook is a service for companies and corporations. Facebook is the most accurate, sophisticated demographic generator in the world. When a company wants to advertise to 23 year old, catholic, single, Arab linguists, from America, who like anime, they can go to facebook and buy ads that specifically target those people. Making it exponentially more likely that the people seeing those ads will click on them. Thus facebook only needs to be good enough to the users (us) that we don't abandon it wholesale, while at the same time prompting us to upload as much information about ourselves as possible.\n\nI saw a political cartoon on here earlier. It shows two pigs in a slaugherhouse called \"facebook pork\" (or some other such label that indicated beyond doubt that it was a slaugerhouse). And the pigs are inside marvelling, \"and there's free food too?! A safe place to sleep?! This is awesome!!\" Of course, they don't know that their whole purpose of being in there is so that they can be fed to people.\n\nThe only real question is whether Zuckerberg said \"I think this would be a great way for people to connect with each other\" and then realized the best way to monetize it. **Or** if he said \"you know what would sell like hotcakes? Really specific demographic information. I think I know how to get it.\" (a la chicken/egg)",
"Basically anything you submit to Facebook becomes their property; Pictures, personal information, everything.\n\nPeople complain about privacy and then go and spill every single detail of their life to Facebook, thus Facebook is \"exploiting\" idiots.",
"The whole premise of facebook is in the interests of exploiting the public.\n\nPeople who haven't stopped to think about it think that facebook is a service provided to the general public allowing us to connect electronically with the people in our lives. They think that this service is financed by the tiny ads on the margins.\n\nIn fact, facebook is a service for companies and corporations. Facebook is the most accurate, sophisticated demographic generator in the world. When a company wants to advertise to 23 year old, catholic, single, Arab linguists, from America, who like anime, they can go to facebook and buy ads that specifically target those people. Making it exponentially more likely that the people seeing those ads will click on them. Thus facebook only needs to be good enough to the users (us) that we don't abandon it wholesale, while at the same time prompting us to upload as much information about ourselves as possible.\n\nI saw a political cartoon on here earlier. It shows two pigs in a slaugherhouse called \"facebook pork\" (or some other such label that indicated beyond doubt that it was a slaugerhouse). And the pigs are inside marvelling, \"and there's free food too?! A safe place to sleep?! This is awesome!!\" Of course, they don't know that their whole purpose of being in there is so that they can be fed to people.\n\nThe only real question is whether Zuckerberg said \"I think this would be a great way for people to connect with each other\" and then realized the best way to monetize it. **Or** if he said \"you know what would sell like hotcakes? Really specific demographic information. I think I know how to get it.\" (a la chicken/egg)"
]
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52ocer
|
where does the sound from the car's blinker actually come from?
|
Seems like it is magically emanating from the dashboard. It seems like a mechanical mechanism, but maybe new cars have blinkers that produce sound electrically? Always made me wonder.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/52ocer/eli5_where_does_the_sound_from_the_cars_blinker/
|
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"It's a relay with a reed switch. Makes noise when activated. They're usually under the dash on the driver's side.\n",
"It comes from a relay switch that is turning off and on. The relay is a small electro-mechanical switch that uses a small voltage, to switch on or off a higher voltage. In the case of a car blinker it is a type of switch that turns off and on when the contact is closed. This can be a purely mechanical timing, or in response to a circuit timer. In mechanical designs, the switch closes, and heats up as current flows, causing it to pull away and break contact, and the light goes off, then as the switch cools it bends back and makes contact again, and will keep going back and forth like this until the control circuit is broken. \n\nThis is also why blinkers may go faster or slower depending on the temperature outside, and why sometimes when you replace the blinker, the car flashes much faster or slower than it used to. \n\nMost of the high voltage or high current devices in your car are switched off and on using relay switches that don't cycle. IE they stay on until you turn them off. The relay allows you to safely use a small voltage, to control a much stronger voltage/current without risk of fire or electrocution.\n\nIn its simplest form, imagine you had a little magnet on a light switch on your wall and you put an electro magnet next to the switch. You can trigger the electro magnet using a 9v battery and this will flip the switch turning your lights off. Reverse the polarity and now it's thrown the other way and the lights come on. Since your 9v battery isn't in direct contact with the high voltage wiring inside your wall, you can safely handle it without fear of electrocution. \n\n",
"There are some cars which use speakers to either make or augment the sound. A coworkers f150 does it. "
]
}
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[] |
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[],
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ub719
|
Why are there distinct lines between the states of matter, instead of just a gradual scale of change?
|
For example, if you had a glass of water (and some way to ensure all the molecules were at the same temperature) that was at 1C, why would it still be "just water" instead of a more gelatinous state?
To my understanding, when a substance changes temperature the molecules vibrate faster or slower, causing them to come closer or move farther away from the other molecules, in turn causing a change of state. So why is it that they stay in a state of "liquid" until they freeze, instead of changing to "almost-solid" as they come closer and closer to the freezing point?
|
askscience
|
http://www.reddit.com/r/askscience/comments/ub719/why_are_there_distinct_lines_between_the_states/
|
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"So, addressing a few misconceptions:\n\nIt really isn't a terribly meaningful statement to describe a single molecule as having a temperature. That said, I assume your idea here is that the entire material is in the same \"condition\" (pressure, temperature, etc).\n\nNext, while it is still \"just water\", it is incorrect to suggest that water at 1C is identical in behavior and structure to water at 50C or 99C. If we consider only \"gelatinous-ness\", which might be more rigorously quantified by density and viscosity, you can see [here](_URL_1_), that there is appreciable variation throughout the temperature range where liquid water is stable.\n\nThat said, you are correct that many materials appear to exhibit a transition temperature across which there is an almost black-and-white difference in behavior and structure: the melting temperature. However, there are many materials that do not exhibit this, or at least not in a terribly accessible or meaningful way. \n\nMany amorphous materials are characterized by what is called a glass transition temperature (which despite its name, is quite different from a melting temperature). Specifically, the glass transition temperature is not a well-defined temperature in many cases, but rather a range over which the transition from a more rigid material (like window glass) to a more viscous material (like melted plastic) occurs. Also, as you may know, the melting temperature of a material is characteristic of that material and for the most part will not change depending on the sample or cooling rate. The glass transition however is very sensitive to many factors including thermal history and cooling rate. \n\nThe glass transition is seen in many everyday materials, including most plastics and glasses (although the temperature range is so high for most glass that you wouldn't ever notice it unless you happened to have access to a high temperature furnace). In fact, the whole glass transition issue makes even categorizing glass as a solid or a liquid a very complex matter. The topic also [came up](_URL_0_) in the last \"misconception\" thread, courtesy of the resident expert on glass physics, EagleFalconn.\n\nEdit: even this is a simplification but the general idea is that it turns out that whole idea of \"solid, liquid, or gas\" is far from comprehensive and often becomes less and less meaningful the more, and deeper, questions you ask.",
" There is a common misconception about melting points (solid to liquid; ice to water) or boiling points (liquid to gas; water to vapor). The melting point means it's the first temperature any liquid will form, not that the substance is now a liquid. Likewise with a boiling point, at t=0s, and T=100C, the first bubble appears, and it's only after some elapsed time at 100C (or greater) that all the liquid turns to gas. (All of which is assuming standard pressure blah blah blah)\n\nIf you have a liquid at 20C, and a gas at 100C, the reason you don't have some half liquid half gas monstrosity at 60C is because of the discrete nature of phase transitions i was alluding to before. At 60C, the water just doesn't have enough energy to turn into a gas (regular evaporation excluded since that's just water molecules getting knocked around by air), it's not until it goes over the energy \"hump\" at 100C that it finally can make the switch to a gas.\n\nOf course however, many substances are not as straight forward as water, but the same principles apply. It's all QM really. In the same way energy levels are discrete (IE you can't have electrons half way in between orbitals), phases are discrete as well and are not a continuous spectrum.",
"The behavior of individual molecules are what give us states of matter. \n\n\nKnowing that temperature is simply a product of the velocity of the molecules (the root mean square of the velocity of the particles anyway), you can start to understand that temperature and pressure will tell us a lot about the way the molecules are moving.\n\n\nWith different molecules, we'll find all kinds of different forces acting between them, such as hydrogen bonds, but all kinds of chemical forces.\n\nSo imagine that there is a sea of molecules, not moving very fast (i.e. cold). Since each molecule moves rather slowly, they don't have the kinetic energy to overcome any bonds and break away. Thus they don't mix freely, but instead stay connected or bonded to nearby molecules, which are in turn attracted to and held together with other molecules. This is a solid. These molecules still have velocities, it's just that they are bouncing around against the invisible walls of their prison made up by the bonds holding them in place. So we think of them as vibrating, rather than moving around. On a human scale, such an object appears as a solid.\n\n\nNow lets add some more vibration to the mix, in the form of heat. As some molecules vibrate faster and faster, they spread these vibrations to their neighbors, and so on and so forth. How efficiently these vibrations are spread will produce what we call conduction of heat. Some materials, because of the nature of the bonds, don't let the vibrations transfer very effectively, and the other side of the structure is unchanged. In other materials, these vibrations will very quickly spread. Once a certain point is reached, a combination of temperature and pressure, which really just means a certain energy given to each molecule, the molecules will suddenly be hitting levels of kinetic energy that are high enough to break out of their bonds and move around freely.\n\nThis is what happens when a solid becomes a liquid. The individual particles are overcoming the amount of force they are held in check with by gaining kinetic energy. In a sample that's at melting point, some particles will be moving freely, some will still be bonded in the structure, as not all particles will reach the energy level at the exact same time.\n\nRemember that the velocity of the molecules are distributed on a bell curve. Some will be around the average, but others will be much higher or lower. Think of it like a swimming pool filled with bouncy balls, in a world without friction, they bounce around, and for fleeting moments, some balls might take on a lot of speed while others might collide and suddenly find themselves completely stopped. \n\nWhen you have a liquid, you have molecules that have enough energy to break free from the strong bonds that made the solid, but they don't have enough energy to break free totally from each other and become a gas. Again, with different elements and molecules, what force this is exactly can vary greatly, and it doesn't really matter for this discussion what force that is exactly, just that there will be an energy level required to be met to overcome those forces to allow a molecule to completely break free and \"fly away\" becoming a gas. \n\nThose bonds that held the particles in a crystal structure are still there and maybe are just strong enough to hold the liquid together. The nature of these bonds can inform the way the liquid performs, such as how much surface tension it has. \n\nAs the liquid warms, the bell curve of energies of the particles shifts to the right, and some of the particles on the extreme side, those much more energetic, that is to say moving faster, than average, will begin to break through that barrier for becoming a gas. Just think about that swimming pool of bouncy balls. If we introduce more vibration into the balls, say by vibrating the walls of the pool, making them bounce more and more, some balls will get enough energy, thanks to some unbalanced collision, that they'll pop up into the air. Remember, a ball getting a lot of energy at the bottom of the pool is just going to collide with nearby particles. But a particle very near the surface just might take that energy and head skyward with enough speed to break through the bonds that hold the particles together. In this example, it would be a ball flying totally out of the pool. Remember that gravity isn't all that influential on the scale of molecules, so imagine this pool is on the moon or some place with even less gravity. \n\nSince the energy is distributed along a bell curve, you see that some particles will reach that point and become a gas before the liquid reaches its boiling point. This is why a glass of water will slowly evaporate even though it is nowhere near boiling. \n\nSweating is a process that cools us. Why? Sweating simply released liquid to the surface of our skin when we're extra warm. So this warm liquid sits on the skin and some of those molecules will get to that energy level needed to break free, and they'll evaporate. When that particle leaves, it takes with it more than the average kinetic energy of one particle, but rather a figure much higher than average. So every time a particle is in an unbalanced collision and takes off with higher than the average kinetic energy, then the liquid that's left behind will be left with a slightly lower kinetic energy. Thus evaporation causes cooling. It's a systematic method for siphoning off particles of very high kinetic energy and thus lowering average kinetic energy. So that's why sweating cools us off, or why putting water on your skin will make you feel cool.\n\nHave you ever gotten alcohol on your skin? It feels even colder than water, not because it *is* colder, but because it evaporates much more easily than water.\n\nAs you heat a liquid closer to its boiling point, you'll see that the more of that bell curve distribution will pass the energy barrier needed to escape. That's why warm water will have vapor visibily rising from it. As water reaches a boil, it's just a matter of a higher percentage of the molecules reaching the needed energy to escape and become a gas.\n\n\nIf you can picture this, then you'll realize that chemicals can have all kinds of different bonds of varying strengths. For instance, you can have a chemical that has a kind of bond that forms a crystal structure (a solid), but when the molecules are given enough energy to break free from this structure, there isn't a force strong enough to constrain them into a sea of particles, and they go straight into being a gas. This is a result of the molecules not having enough bond strength to contain particles once they break out of the crystal structure. We call this sublimation (going directly from solid to gas), and many materials do this. \n\nIf you look closely, you'll find that many materials don't have a liquid state, or do only under intense pressure (because there is a pressure outside, a constant force pressing inward from all directions that combines with the weak bonds to create a situation in which a liquid state is possible. So think of pressure as a friend to bond energy). \n\nPressure isn't always a friend to bond energy though. Consider water. Water is unique in that freezing it actually causes it to expand. Remember that the volume of any thing depends on how much force it exerts on its surroundings. So a balloon with gas particles that are moving very fast will be constantly colliding with the walls of the balloon at high speed, creating a higher pressure, which causes the balloon to expand until it reaches an equilibrium. If you reduce the kinetic energy of those gas particles, they hit the walls of the balloon with less force, and the equilibrium shifts, shrinking the balloon until equilibrium is again reached. So knowing this, it's quite unusual to realize that liquid water, when it loses kinetic energy, will actually expand as it becomes a solid. Why? \n\n\nWell when water is a solid, held in by those strong bonds that don't allow the molecules to move around, only to vibrate within their crystal structure, those molecules are spaced apart in a specific pattern at a certain distance from each other. When water is a liquid, these molecules are moving quickly enough to not be held together by those bonds, but they actually will move fairly close by each other. The crystal strucuture actually increases the amount of space between these bonds. It's just a by-product of the kinds of bonds due to the make-up of the water molecule. So now, imagine Ice right near its melting point. Apply some pressure to that ice. In a balloon, extra pressure shrinks the volume. In most solids, added pressure helps the bonds that are holding the molecules together, giving them a little extra push to constrain the particles. But since ice is spread apart, less dense than water, adding pressure actually hurts the bonds holding the crystal structure. Thus when you look at the phase diagram of water, you'll see the line between solid and liquid has a negative slope. In other words, ice wants to melt under pressure. Understanding this makes ice skating make sense (though the exact science of this isn't really that simple). "
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1lwpv4
|
How and when were all the clocks (time) around the world synced?
|
I am new to Reddit. This question was bothering me for quite sometime now. Thank you so much for the answers, different aspects. Did not expect such a response.
Still trying to figure this out completely though.
**EDIT** : Somebody in the comments mentioned that sync meant all the clock show the same time, so what i meant was different clocks in order with the GMT and time zones.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1lwpv4/how_and_when_were_all_the_clocks_time_around_the/
|
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"As the UK became a maritime nation, boats kept one [chronometer](_URL_0_) on-board so they knew how far away they were from the Greenwich meridian (which is considered to have longitude zero degrees). The chronometer wasn't treated as the actual time, because that was calculated by solar time, depending on where they were. But this, boats travelling back and forth around the world from Britain, meant that people used GMT worldwide as a reference time no matter where they were (there were other reasons, including [this](_URL_3_), but I'm trying to keep it simple). Most time zones were either an hour or a half-hour ahead or behind of GMT.\n\nBasically, trains were responsible for the adoption of GMT as full British time. Railway companies had to adopt a singular time in order to work in unison, otherwise making things very difficult. It didn't happen quickly and there were court battles regarding the case, but eventually they did decide that it was best for the local mean time to be considered as full British time. \n\nAs for other countries, it was never truly set out. There are a bunch of countries (Ireland, Canada, Australia) that have time set out in legislation, but most know it simply by convention. The time simply exists, not set out. \n\nThere were a lot of changes from the deciding of GMT - it was redefined later as [Coordinated Universal Time](_URL_1_), which was maintained by atomic clocks because they were pretty reliable. It was changed again as UT0 and UT1 and UT2 later to make up for small discrepancies such as seasonal variations, earth's rotation, leap seconds and the like. \n\nIt's unfortunately not a particularly interesting topic. The adoption of time was very, very slow, but came about largely as a result of boats and trains needing ways to keep things going smoothly, or \"like clockwork\". In fact, it's taken so long to do that it wasn't until the advent of the internet and GPS and things that clocks all around the world could be properly synchronised (and even then, some people still take issue). \n\nWikipedia has a really good summation of the subject, to be honest. You can read it [here](_URL_2_), but I think what I explained is pretty much the same, and maybe easier to understand. \n\nEdit: adding some extra resources in as links",
"True clock synchronization is a difficult problem, since any communication channel that could be used to synchronize a clock has a nonzero latency that would introduce error into the process. There exist several [algorithms for generating a very good guess](_URL_2_), though.\n\nClocks all over the world aren't truly synchronized at all. Each clock will appeal to some authoritative clock to set itself by, but there is no one single authoritative clock at the top of the chain, although there are a handful that are extremely widely used because they are the most accurate in the world. For instance, in the United States, there is a [single prescribed authoritative clock](_URL_1_) that is considered the absolute standard.\n\nSo, to answer your question more directly, how and how often each clock chooses to appeal to an authority is up to the owners of the clock, so this synchronization is done in a distributed, ad hoc manner.\n\nEDIT: For the more historically-oriented answer to this question, see [/u/ryanbtw's answer](_URL_0_).",
"Stationary observatories could tell the local time accurate to a minute as long as the could measure the stars.\n\nThe challenge is to know the time of a different place to tell your distance from it by comparing it with the time from the stars positions. It also helps to tell time on a cloudy day.\n\nEarly clock tower clocks where easily off 15 minutes per day. Early clocks had the challenge to be accurate independently from moisture, temperature and being shaken, rewound and repaired. They also had to be small enough to be portable. This created and won the _URL_1_ by knowing how different materials contract and expand and by using round springs to create a relatively stable frequency. These where sill relatively inaccurate but at least they could be used on boats across the oceans to know the longitude accurate enough.\n\nMore accurate clocks use more accurate methods to create and utilize a stable frequency of pendulums, springs, quartz or filtered (!) radioactive decay.\nA quartz is more immune from being rotated around the same axis of one of its springs, changing its angular momentum.\n\n---\n\n[Atomic Clocks](_URL_0_) are accurate because they contain a feedback loop that only allows for a certain frequency to become a stable output and it auto-tunes itself to that frequency.\n\nThis feedback loop is much more accurate than a quartz crystal, that only can vibrate in a thin frequency range, but they can get out out tune over time.\n\nThere are multiple very secure atomic clocks at at least 3 places on earth that are far away from each other, to average out relativistic effects.\n\nThey send a very simple long range radio signal that every basic radio-clock, can receive cheaply and with low energy costs to get an accurate global time.\n\nWe now can mass produce an integrated chip less than 1cm³ with an atomic clock inside of it to be independent from the ability to receive that radio signal, and more accurate to higher frequencies than the radio signal can deliver.",
"Ryanbtw answered the concept, but for modern synchro, WWV started broadcasting time signals in 1944 to sync everyone up in North America. _URL_0_\nGPS has probably been the most effective source for syncing up large numbers of clocks such as cell phone towers and etcetera. It is far more accurate than internet based synchronization of desktop computers.",
"A little more about how the railway system shaped the time in the United States:\n\nUp until the second half of the 1800s, (sometime in the 1870s or 1880s), the railways all kept their own times based on the sun's location; it was set in each town with a railway station at noon. This meant that every town in the same time zone set their time based on the sun's location. Time zones, however, are only change by the hour. This meant that, say, Philadelphia would set their clock to noon when the sun was overhead just the same as, say Detroit. But because of the distance between them, their 12:00 times would actually be off by minutes, because the sun is not visible at the highest point in the sky above both cities at the exact same moment. This non-standard time caused a LOT of railway accidents to occur. While this is all going on, Samuel Pierpont Langley (yes, that Langley), has recently been put in charge of Allegheny Observatory in Pittsburgh, PA. He's basically been put in charge of running it and has a telescope but no money for upkeep or expansion. He notices what's going on with the railways and knows that he can tell the time by tracking the positions of stars in the sky. By keeping detailed logs of stars, he was actually able to begin SELLING the time to railway stations. He would sync up his clock based on the stars then send a signal out at exactly 12 noon (according to the stars) that all the other clocks would sync up to. Eventually almost all railway stations bought his time, the observatory began making money, and the number of train crashes that occurred because two trains were on the same track at what they thought were different times dramatically decreased. Langley also invented the bolometer, later became the third director of the Smithsonian, and almost beat the Wright brothers in the race for manned flight--he had a machine flying first, but was unable to fly one with a person inside, despite some famous crashes into the Potomac.\n\nIf you're ever in Pittsburgh on a Thursday-Saturday in the summer (I believe it's April-October), go visit the Allegheny observatory. They can tell the story in more detail and actually have the instruments that he used there.",
"There are crazier story about synchronizing the calendar. My favorite is when the Catholic Church jumped forward 10 days in 1582. Thursday Octorber 4 was followed by Friday October 15. This was to realign the calendar with the celestial motion and started the adoption of the Gregorian Calendar with all of the leap year rules to keep the calendar aligned with celestial motion.",
"Coordinated Universal Time is set by the [BIPM](_URL_1_). Over 200 laboratories in the world with Atomic clocks send their time to the BIPM and this institution creates something like \"the best time possible\". In fact several time scales are set, each one with their own properties, for example, UTC is set in such a way that the sun is always over the Greenwich meridian at noon within one second. In order to achieve this, one second, called leap second, might be arbitrarily added from time to time, if you are calculating time differences this is not good and you should use another scale, such as Terrestrial Time. \n\nThis time scales are published, using the times from the laboratories mentioned before as references, you can find the last publication [here](ftp://_URL_2_). Other institutions might use this information and set their own time scales accordingly.\n\nOnce the UTC (or other time scale) is set there's one more problem: how to disseminate this time around the world? The labs that collaborate with the BIPM are usually responsible of setting the time in their countries and use several methods in order to do this, for example, Spanish observatory of San Fernando is the military institution which sets the time (by law) in Spain, they use radio broadcasting, the [NTP](_URL_0_) protocol, and the telephone as the ways of informing others of the time. ",
"[Radiolab did a podcast about this.]( _URL_0_ )\n\nIt had to do with people missing their trains all the time because nobody had the same time on their clock, often different by 30min or so. So eventually people started adopting the railroad time. ",
"As most of the comments have given a good explanation, I won't. But I would suggest the book \"Einstein's clocks, Poincare's maps\" if you want a very thorough explanation of how clocks become synchronized throughout the world. Also, how time zones came to be, and other ideas that were brought up in place of time zones. ",
"how did the first ever watch maker know that the clock was 'correct'?",
"There was an episode (or at least an article) of [\"Connections\"](_URL_0_) with James Burke in which he lays out how the increasing accuracy of timekeeping enabled greater achievements in travel. \n\nSeafaring required fairly accurate clocks, whereas space travel and satellites require much more accurate synchronization to stay on course.",
"While a lot of people in the thread so far have talked about GMT and railroad time, no one has really mentioned [worldwide time zones](_URL_0_), which I think lies at the heart of your question. You can look at other peoples posts for the lead up but in 1879, Sir Sandford Fleming, proposed the 15° time zones used worldwide today. He was the one that proposed that 180° should be where the new started (international date line now). By 1900, most of the world was using time zones, but not always offset by GMT, using their own local time to offset their time zones. By 1929, most of the world was an offset from GMT. The last country to do so was Napel, in 1986. So the answer to the 'when were ALL' part of your question is 27 years ago, in 1986.",
"Synchronizing the clocks in a large number of train stations was a problem in the late 19th century. And it was one of the issues that started Einstein thinking about time and space and their relationship. ",
"This video by CGPGrey should really help \n\n_URL_0_",
"Radio signals, GPS satellites, and the Internet broadcast signals that indicate the current time. In the United States, NIST (a federal agency under DOC) maintains very accurate atomic clocks in Colorado, and then broadcasts the current time over a variety of mediums, alllowing clocks to set themselves to the correct time. See these links for more: _URL_1_, _URL_0_\n\nClocks are synced all the time.\n",
"Well, it's a bit of a vague question, and it has several answers, but the main things to mention are:\n\n1. The use of astronomical phenomena as Earth-independent time references;\n2. The adoption of prime meridians (as Greenwich) as a navigational reference;\n3. The adoption of standard timezones to facilitate railway schedules;\n4. The invention of the telegraph, followed by break-circuit master clocks that transmit their time over telegraph lines;\n5. The invention of radio, followed by standard time reference signals;\n6. The invention of the atomic clock.\n\nWhile the sun rises and sets at different points in time in different locations on Earth, Renaissance astronomers (if not earlier ones) realized that many astronomical events are seen simultaneously by all observers on Earth. For example, [the eclipses of the Galilean moons of Jupiter](_URL_0_):\n\n > The timing of the Jovian satellite eclipses was also used to calculate an observer's longitude upon the Earth. By knowing the expected time when an eclipse would be observed at a standard longitude (such as Greenwich), the time difference could be computed by accurately observing the local time of the eclipse. The time difference gives the longitude of the observer because every hour of difference corresponded to 15° around the Earth's equator. This technique was used, for example, by Giovanni D. Cassini in 1679 to re-map France.\n\nThis works because if you have an accurate prediction of the time when the eclipse will be seen at one location, you can use it to set your clock to the time for that location. Then you can compare the clock to the local time as observed by, for example, the solar noon. This technique was made feasible by the invention of accurate pendulum clocks between 1657 and 1715. (But note that pendulum clocks are useless at sea.)\n\nStandard meridians (like Greenwich) came into vogue as progress was made on the problem of telling longitude at sea. Two main methods were invented in the 18th century for this: [lunar distances](_URL_3_) and the [marine chronometer](_URL_2_). Lunar distances relies, again, on observing astronomical events that happen simultaneously to all observers on Earth; the chronometer method relies on keeping accurate time at a reference meridian.\n\nStandard timezones were gradually adopted by countries from 1850 until the 1920s, with some late stragglers as late as the 1950s. See [this table from the 1871 Elgin Almanac](_URL_1_) as an example of how things were before standard timezones; for example, the local time in NYC and Philly was 5 minutes apart.\n\nThe invention of the telegraph allowed for near-instant transmission of information across long distances. Since railroads require tight coordination of trains across long distances, they used the telegraph to try and make the time agree on the clocks at all their stations and the watches of all their critical personnel. To this effect *break-circuit* mechanisms were invented, that allowed the \"ticks\" of a *master clock* to be sent over telegraph lines. *Slave clocks* were invented as well that picked up the signal and synchronized automatically to it. \n\nLater when radio was invented, stations were set up to transmit standard time signals for ships at sea to use.\n\nFinally, the atomic clock was invented around 1950. These clocks are more precise than the motions of the Earth or of most astronomical bodies, so the first principle I described (astronomical events observed simultaneously everywhere on Earth) is no longer critical. Now what we have is a collection of atomic clocks in several institutions on Earth, which communicate their time through signals to each other, and their timings are averaged to infer the universal standard time.",
"I work in a watch store and although I can't give you an exact history of when GMT time existed and all the technical knowledge, I know a little bit about how clocks around the world are synced.\n\n\nThere's this cool thing called Atomic Time, or [International Atomic Time](_URL_0_), that a lot of watches nowadays can sync up to that will give you a precise world-time.\n\n\nHow is works: There are radio towers all across the world (for the most part), in North America, United Kingdom, Europe, Japan and China. These radio towers emit in real-time, a signal that essentially any electronic device can pick-up, and will listen to at 4am in the morning when there is the least amount of radio traffic.\n\n\nThis signal is what world clocks and [websites like this that show world times](_URL_1_) are set to and is what your watch will listen for. If it can hear it then it will sync and if it can't then it'll try again later in the day. Pretty cool stuff.\n\n\n"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Marine_chronometer",
"http://en.wikipedia.org/wiki/Coordinated_Universal_Time",
"http://en.wikipedia.org/wiki/Greenwich_Mean_Time",
"http://en.wikipedia.org/wiki/Lunar_distance"
],
[
"http://www.reddit.com/r/askscience/comments/1lwpv4/how_and_when_were_all_the_clocks_time_around_the/cc3ibas",
"http://en.wikipedia.org/wiki/NIST-F1",
"http://en.wikipedia.org/wiki/Clock_synchronization#Solutions"
],
[
"http://www.youtube.com/watch?v=p2BxAu6WZI8",
"http://en.wikipedia.org/wiki/Longitude_prize"
],
[
"http://en.m.wikipedia.org/wiki/WWV_(radio_station)"
],
[],
[],
[
"http://en.wikipedia.org/wiki/Network_Time_Protocol",
"http://www.bipm.org/en/home/",
"ftp2.bipm.fr/pub/tai/publication/cirt/cirt.307"
],
[
"http://www.radiolab.org/2007/may/29/unlocking-the-secrets-of-time/"
],
[],
[],
[
"http://www.imdb.com/title/tt0078588/?ref_=fn_al_tt_1"
],
[
"https://en.wikipedia.org/wiki/Time_zone#Worldwide_time_zones"
],
[],
[
"http://www.youtube.com/watch?v=84aWtseb2-4"
],
[
"http://www.nist.gov/pml/div688/what-time.cfm",
"http://www.wired.com/wiredscience/2013/07/wwvb-time-radio/"
],
[
"http://en.wikipedia.org/wiki/Eclipse#Gas_giants",
"http://elginwatches.org/scans/articles/1871_elgin_almanac/m_pg22.html",
"http://en.wikipedia.org/wiki/Marine_chronometer",
"http://en.wikipedia.org/wiki/Lunar_distance_(navigation\\)"
],
[
"http://en.wikipedia.org/wiki/International_Atomic_Time",
"http://www.timeanddate.com/worldclock/"
]
] |
|
2q71q4
|
Can anyone name an example of a country that fared poorly as a result of having a really open immigration policy?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2q71q4/can_anyone_name_an_example_of_a_country_that/
|
{
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"text": [
"Our [subreddit rules](_URL_0_) don't allow \"throughout history\" questions, so I'm afraid I've had to remove your post. We've found that questions like this end up attracting low effort trivia rather than the in-depth responses people like to see here. If you're interested, I'd encourage you to post a question about immigration policy in a specific time and place."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/wiki/rules"
]
] |
||
1osc17
|
paralysis, specifically if you are paralyzed below the waist, is your genitalia also paralyzed? can a man never have an erection for the rest of his life?
|
I know if you are paralyzed below the waist you practically lose all function of your legs and have to use a wheel chair for the rest of your life...
But does this extend to our personal parts? Would a man never be able to have sex or even masturbate?
Just something that has been on my mind..
FYI: I'm kinda a noob and this is my first post but I LOVE all of you other redditors :D Also i searched ELI5 for another post pertaining to this subject, I'm so sorry if such a post already exists!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1osc17/eli5_paralysis_specifically_if_you_are_paralyzed/
|
{
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"text": [
"Most people who are paralyzed from the waist down do not lose the ability to have and enjoy sex.",
"It depends.\n\nSome people are (effectively) paralyzed because of a muscle issue. So, the nerve connection between brain and muscle is still there, but the muscles can't contract when the signal reaches them, or they're too weak to truly move. So, if it's just an issue of \"the muscles in the leg no longer function properly,\" the genitalia will still mostly function. This would be the case for someone who's effectively paralyzed because of muscular dystrophy, for example.\n\nSomeone with muscle issues may have problems with ferility, though, especially childbirth. A mother whose muscles are too weak to force a child out would have to have surgery to give birth, for example. Men also may have issues ejaculating, because the muscles that actually force the semen out can be too weak. Incontinence can also be an issue.\n\nWith nerve issues, it's more complicated. There are injuries or diseases which affect the brain's ability to actually send signals to the muscles. If the nerves that go down your leg through the hip are cut off or damaged, the genitalia aren't affected. If there's a spinal problem where the cutoff is towards the base of the spine or whatever, that can affect genital functioning. No nerve impulse, no genital functioning. Not only can you not feel anything when the nerves are cut off, but the \"automatic\" reflexes that occur without you doing anything conscious (like your leg kicking when the doctor taps your knee) also fail, since they're also routed through the central nervous system.",
"Since others have hit on non-spinal cord injuries, I'll just focus on those. Your body has a main pathway that moves information from the ends of your body to the brain. This is called the spinal cord. Some of that information never makes it fully to the brain. Instead, there is a path of nerves that moves from one part of the body, then to the spinal cord, then return back to the origin. This is called a reflex arc. So, you have two ways information moves: From finger to brain, and from finger to spinal cord to finger. Let's use a simple example. You are using a hot stove and touch one of the burners. Two things happen: First, and quickest there is a signal sent through the reflex arc causing (Finger, nerve to spinal cord, back to finger) your finger to pulls back very quickly. At the same time, but taking a millisecond or two longer is the sensation of HOT!!! being sent to your brain for interpretation. The purpose of the reflex is to be quicker than the interpretation so you are out of danger without necessarily knowing why immediately.\n\nIn the case of spinal cord injuries, a lot of this depends on where the injury is. If it's too low on the spinal cord, then the nerves needed for both erection (some terminating in the spinal cord as a reflex arc, others continuing to the brain for full interpretation) and the reflex arc nerves for ejaculation will be cut off. If the break is higher, then you might get someone who can have an erection, and have an ejaculation (a function of the reflex arc), but they may not feel it. So, they get hard, ejaculate, but get no sensation out of it. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
6623yk
|
theresa may's announcement of the snap election
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6623yk/eli5_theresa_mays_announcement_of_the_snap/
|
{
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"text": [
"May's Blue party think they're currently doing a lot better than Jeremy's Red party. Because the Blue party are in charge of the tree house just now, they've decided to hold the next election earlier than they need to, which is called a 'snap' election.\n\nAll the members of the tree house get to vote in whether or not the snap election will take place, but if Jeremy and his friends say no then everyone will think they're scared to stand up to May. Everyone who's not a Red or a Blue thinks that they can maybe steal a few of the better chairs in the tree house from the Reds during the confusion. "
]
}
|
[] |
[] |
[
[]
] |
||
185jiv
|
How serious was the Madagascar plan?
|
Was it seriously considered by the Nazi government? Was there any public reception of the plan?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/185jiv/how_serious_was_the_madagascar_plan/
|
{
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"text": [
"Transcript from the Eichmann trial.\n\nThe plan took its final shape during the War. Eichmann admitted that it had been devised and passed on by his Section after consultations and discussions with other authorities. Under this plan all the local inhabitants of Madagascar, about four million persons were to be uprooted, to be removed and deported from there, and in their stead the Jews were to be settled on that island, the main advantage of which was, according to what was specifically stated, that its occupants would be prohibited from coming into any contact - even business contacts - with other nations. There they would be living under the control of the Gestapo and would never achieve any independence. They planned to dump a million Jews there each year. Whoever studies this atrocious plan which originated with him, will come to the conclusion that its principal objective was to take control of the Jews, to throw them out of Europe, and to transport them to a country of exile, a country in which they would be isolated from the world. Whether the Jews succeeded in surviving there, or not - that did not matter, that Eichmann did not take into consideration. \n\nHe was questioned about the plan. The Court will find his replies on the subject. From the point of view of its cruelty and lack of consideration for human life, its being pervaded with hatred of Jews, its being drawn up in total disregard for the inhabitants of the island of Madagascar themselves and for the Jews destined to be deported there - it was not much better than a plan for actual extermination. Whoever was capable of preparing such a plan, recommending it and striving for its implementation - would not find it too difficult to move to the next stage of the criminal plot. But it was impertinent and insolent to mention this plot in the same breath as Herzl and the Zionist movement. \n\nPossibly Eichmann was incensed that his schemes were not adopted. Possibly he expected that his name would be linked, as it had been linked at the ministerial meeting of 12 November 1938, with the practical solution of getting rid of the Jews - the aim which a veteran National Socialist should obviously have aspired to achieve. Possibly he toyed with the idea that if his programme were to be implemented, he - and not Heydrich - would be the Supreme Commissioner for Jewish Affairs. \n\nAt any rate,instead of Madagascar, there came the extermination plan. Eichmann admits that he knew about it already from its early stages, in the summer of 1941, and that he had an active role in its realization. As I have said, he tried to persuade the Court with all his might, that it was only through lack of an alternative and because he could not free himself, that he had to become engaged in this activity. Although, as I have said, it makes no difference, as regards his being found guilty, whether a murderer acts out of an eager lust for blood or out of \"pessimism,\" as Eichmann portrayed his mental condition regarding the Final Solution. But for the purpose of assessing the man, of considering his testimony and evaluating the personality which he tried to present for himself, for understanding the group of his collaborators and their assistants who carried out the numerous works, there is some importance also in this enquiry. The truth came out as it emerged from a particular passage from his conversation with Sassen, about which he was questioned twice.",
"For a great summary of varying opinions, I recommend Christopher Browning's paper on Nazi Resettlement Policy. In it, he discusses both sides to the argument, was it serious or not summed up as a part of the old internationalist vs. functionalist debate. Here's parts of the essay: [Google Books](_URL_0_) \n\n"
]
}
|
[] |
[] |
[
[],
[
"http://books.google.com/books/about/The_Path_to_Genocide.html?id=L1O2ZvS29DYC"
]
] |
|
js20b
|
how military units get their numbers? like where does 25th id come from? wheres 24th id?
|
I dont understand the number structures at all and what they symbolize. I get that there is like a 1st INF DIV but why is their FA unit Charlie 3-07 (just as an example)?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/js20b/eli5_how_military_units_get_their_numbers_like/
|
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"this is probably better off in /askreddit than eli5",
"I always wondered why we only hear about the 82ond and 101st Airborne-the 83rd must be pissed!",
"It's largely random. In WWII we had the first, second, and third armies, but then you get reasons like:\n\n-SEAL Team 6: Actually the second SEAL Team, but we wanted the Russians to think we had more.\n\n-112th Airborne: Made up of 2 different units, something like the 50th and 62nd, couldn't decide whose number to take when they got combined, so they just added them.\n\nOther units were just split up and given \"the next number\" that wasn't being used and then became autonomous by circumstance, so they were reinforced and became their own unit. Really there's no single rhyme or reason to it.\n\nCharlie 3-07 sounds more like a callsign. Like the 7th crewman in the 3rd vehicle of Charlie platoon.",
"Some of these units were wiped out and others absorbed by other units that had not lost as many men. You don't have the resources to constantly change the numbers (repainting vehicles, new patches on everything, record-keeping continuity, etc) so the surviving units retain their old numbers. The rest were either killed off or had their numbers slowly reduced through attrition until the remaining members were dispersed to similar units.",
"It's actually quite simple. The military numbers divisions (10,000 - 15,000 people) as they're created. When they are deactivated, that number is simply dropped, but they keep naming new divisions counting up from the last number used.\n\nThe military used to use the same method for numbering regiments (3000 - 5000 people), but they stopped doing that during the Civil War when some states made their own numbers for regiments. Now I think the regimens simply decide on a number, I'm not sure.\n\nThe military will also combine regimens as needed into each division. So it makes the regimen numbers in the division seem random, because they don't renumber the regiment when it's placed in a division.\n\nEDIT: Not regimen, regiment.",
"It gets even more confusing when you start considering Aviation Units. The 2nd Marine Aircraft Wing hosts VMA-231, VMA-223, VMA-542 under MALS-14... VMA as it was explained to me stands for Fixed Wing Marine Attack Squadron and I have no clue where our numbers came from. MALS is Marine Aviation Logistics Squadron which kinda feeds us our intel and some of our 2nd level engineering. I never really questioned our numbering systems all that much but since you mention it... they make no fucking sense.",
"For the second part of the questions the 24th ID (like the 25th ID) started life as the 'Hawaiian Division' in the 1920s (consisting of troops from, or stationed in, Hawaii) - That division was split into two new divisions under the new 'Triangular' structure in 1941, and they were present when the Japanese bombed Pearl Harbor.\n\nThey fought right through WWII in the Pacific Theatre, ending up as a part of the army of occupation in Japan. They were the first US unit committed during the Korean War, served in Germany during the Cold Ware and Desert Storm in 1991. After that they became a training unit in the US, and were deactivated in 2006.",
"this is probably better off in /askreddit than eli5",
"I always wondered why we only hear about the 82ond and 101st Airborne-the 83rd must be pissed!",
"It's largely random. In WWII we had the first, second, and third armies, but then you get reasons like:\n\n-SEAL Team 6: Actually the second SEAL Team, but we wanted the Russians to think we had more.\n\n-112th Airborne: Made up of 2 different units, something like the 50th and 62nd, couldn't decide whose number to take when they got combined, so they just added them.\n\nOther units were just split up and given \"the next number\" that wasn't being used and then became autonomous by circumstance, so they were reinforced and became their own unit. Really there's no single rhyme or reason to it.\n\nCharlie 3-07 sounds more like a callsign. Like the 7th crewman in the 3rd vehicle of Charlie platoon.",
"Some of these units were wiped out and others absorbed by other units that had not lost as many men. You don't have the resources to constantly change the numbers (repainting vehicles, new patches on everything, record-keeping continuity, etc) so the surviving units retain their old numbers. The rest were either killed off or had their numbers slowly reduced through attrition until the remaining members were dispersed to similar units.",
"It's actually quite simple. The military numbers divisions (10,000 - 15,000 people) as they're created. When they are deactivated, that number is simply dropped, but they keep naming new divisions counting up from the last number used.\n\nThe military used to use the same method for numbering regiments (3000 - 5000 people), but they stopped doing that during the Civil War when some states made their own numbers for regiments. Now I think the regimens simply decide on a number, I'm not sure.\n\nThe military will also combine regimens as needed into each division. So it makes the regimen numbers in the division seem random, because they don't renumber the regiment when it's placed in a division.\n\nEDIT: Not regimen, regiment.",
"It gets even more confusing when you start considering Aviation Units. The 2nd Marine Aircraft Wing hosts VMA-231, VMA-223, VMA-542 under MALS-14... VMA as it was explained to me stands for Fixed Wing Marine Attack Squadron and I have no clue where our numbers came from. MALS is Marine Aviation Logistics Squadron which kinda feeds us our intel and some of our 2nd level engineering. I never really questioned our numbering systems all that much but since you mention it... they make no fucking sense.",
"For the second part of the questions the 24th ID (like the 25th ID) started life as the 'Hawaiian Division' in the 1920s (consisting of troops from, or stationed in, Hawaii) - That division was split into two new divisions under the new 'Triangular' structure in 1941, and they were present when the Japanese bombed Pearl Harbor.\n\nThey fought right through WWII in the Pacific Theatre, ending up as a part of the army of occupation in Japan. They were the first US unit committed during the Korean War, served in Germany during the Cold Ware and Desert Storm in 1991. After that they became a training unit in the US, and were deactivated in 2006."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
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[],
[],
[],
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|
40sqo7
|
why should one's beliefs impede another's rights, especially if the other doesn't subscribe to their belief system?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/40sqo7/eli5_why_should_ones_beliefs_impede_anothers/
|
{
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"Christians believe being around gay people or being forced to serve them food in their restaurant is the same as \"being forced to accept homosexuality\". In Christianity, homosexuality is a sin punishable by death, no different from murder. \n\nAlso, they believe gay marriage or gay rights are special rights. They believe it is equal because no one should have the right to marry someone of their same sex.",
"It is unavoidable that if your \"rights\"... lets just say freedoms... are to be impeded in any way that this is done according to someones (presumably most peoples) beliefs. In other words, if you are forbidden from doing something, it's because of some belief that you should be.\n\nClearly, you and I should be forbidden from doing some things. Clearly high on the list are things that harm others directly, like murder. But this is forbidden because we believe it should be so.\n\nLower on the list are things that are forbidden because they are 'wrong'. We forbid cruelty to animals, even though they have no legal rights. I think we all believe this is as it should be, but that is only a belief, and has not always been so, certainly not in certain societies.\n\nI could go on, but the point is that belief of some kind is at the root of all restrictions or exhortations - including the desire to limit the influence of some beliefs, else you'd likely still be ruled by a king or other absolute ruler.\n"
]
}
|
[] |
[] |
[
[],
[]
] |
||
9bjjzh
|
plato's theory of forms and aristotle's criticism to it
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9bjjzh/eli5_platos_theory_of_forms_and_aristotles/
|
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"Basically there's a place where there's a perfect form of everything that exists. Like a perfect chair or perfect cat or perfect pencil. According to him when we are born we are born with the knowledge of all these perfect forms but we forget as we get older so we live in an imperfect version of the perfect form world. In other words there are no new inventions we are just remembering. ",
"Both were wrestling with the human experience of the abstraction of ideas and terms for things in the world. E.G. we think lots of things are beautiful, so what is \"beauty\"?\n\nPlato argued that things like \"beauty\" were abstract concepts (and universal concepts) that exist independent of the things we'd describe as beautiful. E.G. \"beauty\" is a form, and \"a beautiful flower\" is a flower that invokes that abstraction.\n\nAristotle rejects this abstraction and says that beauty is an inherent attribute of the object and we can't talk about them independent of the objects themselves in any real sense. E.G. the idea that beauty somehow exists without us having any objects we'd describe as beautiful is non-sensical.\n",
"Little Kid: \"Dad, what's a dog?\"\n\nDad: \"Well, we have Buster at home. Buster is a dog.\"\n\nLittle Kid: \"Yeah, but what *makes* Buster a dog?\"\n\nDad: \"Well, he walks on four legs and is covered in fur.\"\n\nLittle Kid: \"Yeah, but so does our cat Oscar.\"\n\nDad: \"Yeah... well, Buster barks.\"\n\nLittle Kid: \"But bears walk on four legs, are covered in fur, and kind of bark. Are bears a type of dog?\"\n\nDad: \"No dingbat, bears aren't a type of dog. When I tell you to think of a dog you don't think of a bear do you?\"\n\nLittle Kid: \"No . . . but what if you shave Buster? Is he still a dog with no fur? Cause that's not what I think of when I think of a dog.\"\n\nDad: \"No, he's still a dog. He's just . . . different. Dogs just sort of have that dog-like quality to them. I guess dogs are just something where you know it when you see it.\"\n\nThis sort of illustrates Plato's Theory of Forms and Aristotle's critique. Plato was basically saying that when you're trying to define something, you ultimately will need to invoke a kind of knowing that isn't a matter of grasping a definition of one term by means of another terms, but of grasping the thing itself. In other words, the concept of a \"dog\" is an abstract universal entity that exists independent of dogs themselves.\n\nAristotle said yeah, but there must be some knowledge of the substance which is *in* the thing. There must be something *in* Buster, some type of dog-like quality, which makes Buster a dog."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
6a8tyt
|
why are videogame consoles and other electronics arranged in rectangular prisms rather than cubes?
|
Is there a direct reason for it? Is it more efficient/powerful or is it just for looks?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6a8tyt/eli5_why_are_videogame_consoles_and_other/
|
{
"a_id": [
"dhclkkn"
],
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2
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"text": [
"They're based around circuit boards which tend to be flat and not square. Making a cube would either result in a *giant* cube, forcing you to make your circuit board really tiny or splitting the electronics into multiple square boards & adding some sort of interconnect between them, none of which are ideal solutions.\n\nFor one example, [here's the inside of an XBox 360](_URL_0_)."
]
}
|
[] |
[] |
[
[
"http://www.consolezombie.com/Images/Xbox360Disassembly/xbox-360-motherbard-2.jpg"
]
] |
|
1p5u2v
|
Serious: Is the increase in detection and diagnosis of all Cancers in any way related to the increased levels of radioactive materials in circulation globally?
|
Medical student here, who is curious as to the vastly increased levels of detection and diagnosis of all forms of malignancy and cancer. Yes, a lot can be attributed to increased life expectancy, subsequent shortening of telomeres and thus increased susceptabilty to DNA instability. BUT, does the post WW2 increased levels of ionising radiation possibly play any part on a global scale? And will this reduce in time due to the lack of discharge of nuclear weapons in the modern era? Thanks
|
askscience
|
http://www.reddit.com/r/askscience/comments/1p5u2v/serious_is_the_increase_in_detection_and/
|
{
"a_id": [
"ccz7jyu"
],
"score": [
7
],
"text": [
"In short: no. Only a [small fraction of cancers](_URL_0_) is attributable to radiation.\n\nThere are several reasons that cancer is more prevalent (or appears more prevalent) in recent years.\n\n1) Age is the #1 risk factor for cancer. In other words, the older you are, the more likely you are to develop it. This means that as the rest of medicine gets better, and lifespans are extended, cancer is more likely.\n\n2) We are much better at detecting and diagnosing cancer than 200 years ago. The better we are at seeing it, the more people we realize have it.\n\n3) Lifestyle factors (smoking, diet, obesity, exercise) together account for roughly 2/3rds of the cancer we see in the US. In the past 100 years, smoking rates have exploded (although they are on the decline now), and there is an epidemic of obesity. This greatly increases the number of cancer cases each year. Additionally, HPV leads to large numbers of cancers in the cervix, head & neck, and several other sites.\n\n4) Cancer treatment has extended the lifespan of people with cancer by many years. This means that there are more people alive who either have cancer or have had cancer. This is the \"awareness\" factor that can make it appear more prevalent.\n\nRadiation causes cancer, but isn't nearly as strong of a carcinogen as many people think. Here's a question for you: we've done lots of studies on the people exposed to the atomic bombs in Japan during WW2. For those who survived the bombings, what do you think the excess risk of cancer death is?"
]
}
|
[] |
[] |
[
[
"http://www.cancerresearchuk.org/prod_consump/groups/cr_common/@nre/@hea/documents/image/cr_082588.pdf"
]
] |
|
3vlqtr
|
why do veins swell when you constrict your blood flow?
|
When I put squeeze my arm just below my elbow, the veins on my forearm swell considerably. Why is this? Wouldn't you just be restricting blood from entering your arm to cause this?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3vlqtr/eli5_why_do_veins_swell_when_you_constrict_your/
|
{
"a_id": [
"cxol7fr"
],
"score": [
5
],
"text": [
"Blood flows out from your heart along arteries, and back to the heart along veins. Blood pressure is very high in the arteries, and low in the veins - it's the drop in pressure that carries it through your circulatory system.\n\nSo, grab your arm above the elbow, and what's happening? You're constricting the whole area, raising the internal pressure. Think of the arteries, running deep down in the tissue, as high pressure hoses. You're squeezing them, but that has little effect. Meanwhile, the veins are made of floppy tissue that carried blood under low pressure, so your grip is enough to collapse them.\n\nThat means that blood is flowing out to the arm, but having trouble coming back.\n\nAs the veins are only used to holding low pressure their walls are weak and flexible. When all that extra blood has to go somewhere, they balloon out and fill with it."
]
}
|
[] |
[] |
[
[]
] |
|
76qkf8
|
what is border adjustment and how will it let trump force mexico to pay for the wall?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/76qkf8/eli5_what_is_border_adjustment_and_how_will_it/
|
{
"a_id": [
"dog1v1g"
],
"score": [
2
],
"text": [
"I'm not an expert. But as I understood it, the border adjustment simply means import/export toll (I don't know the English word; I mean the fee you or a company has to pay to be allowed to transport goods to another country) is changed. Less import taxes for US Companies, and more export taxes for Foreign (Mexican) companies. This way, rather than paying the price of the wall directly, Mexico will \"pay\" through their companies paying import tolls to the US. Of course, that could mean Mexican Companies shift their export to other countries than the US, should that be possible. I can't give a guarantee that this is correct."
]
}
|
[] |
[] |
[
[]
] |
||
1ug1cd
|
Why isn't matter evenly distributed across the universe?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ug1cd/why_isnt_matter_evenly_distributed_across_the/
|
{
"a_id": [
"cehtyyp",
"cehzz2l",
"cei1aoh"
],
"score": [
10,
3,
2
],
"text": [
"It is, just not on small scales. The basic structure of the universe on large scales is galactic superclusters, to clusters, to galaxies, to stars. At supercluster level, the universe is very evenly distributed.\n\n[this](_URL_0_) link gave a good description of how the local distributions came about.\n\nTo paraphrase, matter was completely even after the inflation, but even natural variations break the evenness on small scales (in this case, atoms being slightly to the left, or similar). These small variations eventually led to grouping of matter naturally.",
"Inflation and gravity, for the most part.\n\nAveraged out over very large scales - larger than about a hundred million light years - the Universe *does* look the same everywhere, with a smooth, uniform distribution of matter.\n\nYou wouldn't expect the Universe necessarily to start off like this. It's believed that a period of accelerated expansion a fraction of a second after the Big Bang, called [inflation](_URL_0_, would help smooth things out and leave the Universe uniform. But inflation has a side effect: it also blows up fluctuations in the density on the smallest scales caused by quantum uncertainty. Inflation is so effective that these tiny fluctuations, which normally die down in a split second, are expanded to cosmic sizes, and are imprinted on the fabric of the Universe.\n\nA long time after inflation ends, these blown-up fluctuations remain as slight but crucial differences in density from one place to the next. Millions of years later, the Universe was mostly uniform still, but in the places which inflation left ever-so-slightly more dense, gravity is ever-so-slightly stronger, and the Universe expands there at an ever-so-slightly slower rate than the surrounding areas. So gravity causes those parts to collapse. That's where galaxies and galaxy clusters form, leaving the Universe much clumpier than it was before.",
"[This image](_URL_1_) is the Planck telescope's picture of the universe at large scales. The red blob across the middle is our own Milky Way galaxy getting in the way (photobombing, essentially).\n\n[This](_URL_0_) is how it looks when you remove the Milky Way and a few other things (accounting for the motion of the Earth+Sun, for example).\n\nNote: the variations you see in this second image are *very* tiny. The variations you see are, as others have said, echoes of tiny quantum fluctuations that were magnified during the inflationary period of the very early universe."
]
}
|
[] |
[] |
[
[
"http://www.esa.int/Our_Activities/Space_Science/Planck/The_cosmic_microwave_background_and_the_distribution_of_matter_in_the_Universe#TK3a"
],
[
"http://en.wikipedia.org/wiki/Inflation_(cosmology)"
],
[
"http://spaceinimages.esa.int/var/esa/storage/images/esa_multimedia/images/2013/03/planck_cmb/12583930-4-eng-GB/Planck_CMB.jpg",
"http://www.mpa-garching.mpg.de/mpa/institute/news_archives/news0905_planck/fig1.jpg"
]
] |
||
akmwea
|
When And Why Did Children's Books Emerge?
|
Not necessarily picture books, but books aimed specifically at a younger-than-adult audience.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/akmwea/when_and_why_did_childrens_books_emerge/
|
{
"a_id": [
"ef704gy"
],
"score": [
18
],
"text": [
"I did an overview of pretty much the entire history of children's literature in [this answer about the rise of YA lit](_URL_0_), though I skirt around spending a lot of time doing in-depth discussion surrounding the beginnings of children's literature. If you're not satisfied with that answer and would like me to go more in-depth on that front, I'd be happy to do so."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/9uj0qw/when_did_ya_young_adult_literature_become_a_genre/e9584oe/"
]
] |
|
2drcgc
|
the rick perry indictment
|
Why is he being accused of corruption? Who is Lehmberg and is she a nutjob? Was his refusal to fund the cancer research agency illegal? How are Texans responding do this, on both sides of the aisle?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2drcgc/eli5_the_rick_perry_indictment/
|
{
"a_id": [
"cjs9tbi"
],
"score": [
19
],
"text": [
"Lehmberg is an elected district attorney. As such, she cannot be fired directly by Governor Perry. Lehmberg was charged with a DWI back in 2013, did some jail time, and successfully defended her position in a civil suit. Governor Perry does not want Lehmberg to remain in office, so he threatened to veto $7.5 M in funding specifically set aside for a public corruption unit that operates out of Lehmberg's office, unless she stepped down. She did not, so Perry vetoed the funding.\n\nA complaint was filed against Governor Perry for this and presented to a grand jury, who indicted him on charges of abuse of an official capacity, and coercion of a public servant."
]
}
|
[] |
[] |
[
[]
] |
|
677ouo
|
how do shows like last week tonight identify clips for a clip montage?
|
Tonight's Last Week Tonight ended with a montage of Bill O'Reilly that had sexist and racist clips of him from the past 20ish years. I realize it wouldn't be hard to find such clips in this particular instance, but they do this every week. I doubt they have a team of people watching episodes to find content. So, how do they do it?
Do they have access to transcripts for every show ever and simply search for keywords? Is there a company that archives and sells these transcripts?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/677ouo/eli5_how_do_shows_like_last_week_tonight_identify/
|
{
"a_id": [
"dgoc5ho"
],
"score": [
2
],
"text": [
"Studios have library / archive services that will sell you clips to use. For example, [NBCUniversal Archives] (_URL_0_) has clips from their news shows.\n"
]
}
|
[] |
[] |
[
[
"https://www.nbcuniarchives.com/"
]
] |
|
urtt3
|
How did early films get copied and mass-produced?
|
[This](_URL_0_) textbook states:
> Ways of recording motion on film were first developed by photographers Étienne-Jules Marey and Eadweard Muybridge in the 1880s. Inventor and entrepreneur Thomas Edison applied their ideas in building the first practical motion picture display system, the kinetoscope. In France the Lumière brothers invented the first portable movie camera and the first projector that could be used to display movies to a crowd.
> Early directors such as Edwin S. Porter developed movie storytelling techniques that were expanded eventually into the feature-length film by D. W. Griffith. Griffith demonstrated that the public was interested in and willing to pay for larger-than-life films with longer running times. Griffith was also one of the first directors to seek outside financing for his movies.
This is a great start, but it doesn't state the process that was used to copy films. Did people just bring their film to different theaters and set it up? Like a touring theater company or something? What about the first mass-distributed films; did they copy them frame by frame, or was there a machine to do it?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/urtt3/how_did_early_films_get_copied_and_massproduced/
|
{
"a_id": [
"c4xzw4t"
],
"score": [
3
],
"text": [
"While I can't give a good answer, I can say what I would do if I had their technology. \n\nI would take an unexposed reel and match it up with the film's reel. Laying the two strips over one another, shine a light through the original and then through the new film. The original film will filter the light that will then expose the new filmstrip.\n\nI know very little about the mechanics of old film, but I imagine this might have worked. Can't tell you if it's what they actually did, though. I'll ask some of my friends in film, they might know better."
]
}
|
[] |
[
"http://college.cqpress.com/sites/masscomm/Home/chapter8.aspx"
] |
[
[]
] |
|
4gtwg5
|
how does a thermal explosion cause a human to get knocked back, as often seen in action movies?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4gtwg5/eli5_how_does_a_thermal_explosion_cause_a_human/
|
{
"a_id": [
"d2kmqda",
"d2ko7tg",
"d2kqixn"
],
"score": [
47,
8,
4
],
"text": [
"Movies aren't always representative of real life. Action movies even less so.\n\nOf course, it's possible for an explosion to knock people back. Because of the rapidity with which explosion take place, they almost always create a shock wave. The problem with being knocked back with the shockwave from a thermal explosion, however, is that the shockwave is likely many thousands of degrees. Of course, only being in contact with it for a short time, you wouldn't necessarily be burnt to death (unless it was a *really* hot bomb), but it certainly wouldn't be as clean as movies lead us to believe.",
"Its called a shock wave; I'll try my best at an ELI5. If you push on a solid object, obviously the other side of the object moves at the same speed. When you push on liquid, like when you're swimming, the little bits of water push on each other and if you were close enough to where it was being pushed, you could feel that too. You don't feel the push as strongly because the little bits of water are able to slide around each other. You can push on air the same way, but the little bits of air move around each other more easily than anything else, so the push fades pretty quickly across distance. \nWhen there is an explosion, the air is pushed so quickly that the other bits of air in front of it are not able to move out of the way, so it's much more like pushing on something solid. If someone is close enough they'd feel that push. \n(My first attempt at one of these, hope I helped)",
"Bona fides: among a few things in life I wrote a book that was adopted by the FBI National Academy and the US Army Bomb School as a textbook, did two tours Afghanistan, for whatever that's worth to the perceived accuracy of what I'm about to say.\n\nThe question seemed sincere so I'll be sorta specific. Excuse any bomb-geekiness. While there is a term 'thermal explosion' or thermal runaway, in the layman's language the word 'thermal' revers to one of three components of a bomb blast: heat, shock and fragmentation.\n\nHeat is simple to understand. At the heart of a conventional blast a chemical reaction cranks out a helluva lot of heat. To put that in perspective, at the Oklahoma City bombing, streetlights down the block were melted. But heat alone won't throw you; it will burn or ignite stuff.\n\nFrag is easy as well: every solid thing the bomb was made of, and every solid thing the bomb blows apart, goes flying at 'way-past-bullet-speeds.' Frag can be tiny slivers of metal, rock or wood, or in the case of the detonation of the USS Grandcamp, a piece of frag would include the ship's 10,000+ pound anchor that flew about half a mile. There is a technical difference between fragmentation and shrapnel, but that goes into geekiness for another discussion.\n\nShock: so imagine doing a cannonball in the pool. You hit the surface of the water and your body in the blink of an eye moves, or 'displaces' a whole lot of water, shoving it out and away from you in all directions. I will skip comparative compressability of water and air but for simple analogy say that in an 'air cannonball' if you froze time at the moment of impact, the air shoved away is moving faster than the air an inch, or a foot, beyond, so the moving air compresses into the space along with the still-stationary air (remember, this is like mili-second type speeds). What you get is a hollow ball of compressed air. So think about the \"thickness\" of the hollow ball as this expanding shockwave that is racing out. In the case of C4, it is racing out at about 26,000 feet per second. That's where the 'guys get thrown in movies\" effect is supposed to come from, but reality is a bit uglier. Here's the ELI5 on why:\n\nIf you fired a high powered rifle, lets say a 50BMG, the bullet leaves the gun barrel at roughly 3,000 feet per second. If you set off a big explosion 100 yards BEHIND the rifle at the exact same instant, would the explosion eer catch up / pass the rifle bullet? Yep, in just a shade under 0.005 of one second (and /r/physics redditors, I am skipping deceleration factors, exponential degradation, etc....) Point being, since an eye blinks in about one-third of one second, quite literally \"in the blink of an eye\" the explosive shockwave a football field away would blow by you. That is so freakishly fast that a living body, which is not a solid but a bag of solids, semi-solids and liquids, cannot accelerate uniformly to \"surf the wave\". So parts of the body catch the wave and race off while other parts get left behind. People can go from being people to being parts, to being, hm, just mulch, sometimes just being gone.\n\nPlenty of video on the subject, here is a decent one _URL_0_ skip to about 30-40 sec and look for the curved \"haze\" just outside of the obvious orange parts of the explosion. That is the shockwave.\n\nMay be more than you wanted but I hope it fills in some blanks."
]
}
|
[] |
[] |
[
[],
[],
[
"https://www.youtube.com/watch?v=K9eTzokEnMs"
]
] |
||
4fa173
|
how broadcasters get such good sound of professional athletes while they are on the field.
|
Do they mic their helmets? Or do they have mics strategically place around the ice/court/etc? Fascinating imho.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4fa173/eli5_how_broadcasters_get_such_good_sound_of/
|
{
"a_id": [
"d274nej",
"d274npd"
],
"score": [
11,
2
],
"text": [
"The use [parabolic microphones](_URL_0_). They put a directional microphone at the focal point of a big bowl, and it makes it ultrasensitive towards sounds from a particular spot. ",
"One way is with those microphones that have parabolic dishes directing the sound into the microphone at the focus point. You can see them being used in the sidelines. Sorry, I'm not sure what they're called."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Parabolic_microphone"
],
[]
] |
|
atj1nz
|
How does density affect the speed of seismic waves through the Earth?
|
So, correct me if I'm wrong, the speed of the seismic waves increase with depth in the mantle but the speed decreases as it enters more dense material (i.e. the core)?
I thought waves traveled faster through more dense materials as a rule.
Could somebody please clarify this for me. Thanks.
|
askscience
|
https://www.reddit.com/r/askscience/comments/atj1nz/how_does_density_affect_the_speed_of_seismic/
|
{
"a_id": [
"eh1cgo1"
],
"score": [
8
],
"text": [
"Waves travel more slowly through denser material. A lot of people have this misconception because, for example, sound travels faster in water than air, and faster in steel than water. But actually the increasing density is impeding the speed of sound. It's the increased stiffness (elastic modulus) of these materials that drives their faster speed of sound. "
]
}
|
[] |
[] |
[
[]
] |
|
7m9vps
|
Historians, what was Christmas like during the American Revolution?
|
We hear heart warming stories about "truces" during The Great War but what about during the American Revolutionary War?
Responses about the Nepoleonic Wars or others would be interesting as well!
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7m9vps/historians_what_was_christmas_like_during_the/
|
{
"a_id": [
"drwuqsh"
],
"score": [
2
],
"text": [
"Christmas night 1776 General Washington crossed the Delaware river to mount a surprise attack on Hessian mercenaries in Trenton New Jersey. Not the heart warming story you were looking for but a Christmas story none the less.\nEdit:\n The following year Washington's Army was at winter quarters in Valley Forge where roughly half of his forces were sick/injured/or dying."
]
}
|
[] |
[] |
[
[]
] |
|
1ql95u
|
What was the result of the location of pangea, and the resulting difference in earth's centermass?
|
back in the days of pangea, all the continents were shifted to one area of the sphere we call earth. This altered the center mass position of our sphere, which must have changed the way in which it spun, tides, etc, RIGHT?
Also, (and yes i've heard of plate tectonics) over time is earth's continental shifting resulting in a more evenly distributed sphere?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ql95u/what_was_the_result_of_the_location_of_pangea_and/
|
{
"a_id": [
"cde1h04"
],
"score": [
4
],
"text": [
"Firstly, Pangea was only the [most recent](_URL_0_) of at least 6 supercontinents that have existed in Earth's history. It formed about 300 million years ago, and started breaking up about 175 million years ago.\n\nSecondly, as far as mass of the planet is concerned, the vast, vast majority is contained in the mantle and core, which are 2-6 times more dense. The crust makes up about 0.9% of the earth's volume, and just 0.5% of the earth's mass. Remember, the tectonic plates are up to *maybe* 100 km thick at their absolute maximum (35 km average for continental), whereas the earth is 12,742 kilometers across\n\nThirdly, the crust is lying buoyantly on the mantle, which deforms below it. What that means is that while continental crust is less dense and thicker than oceanic crust, the load on the underlying mantle is around about [the same](_URL_1_). \n\nAll this acts to make the effect on centre of mass negligible. "
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Supercontinent",
"http://en.wikipedia.org/wiki/File:Airy_Isostasy.jpg"
]
] |
|
2oj5d4
|
Does fungus build up a resistance to treatment like bacteria does?
|
Antibiotics should be used only when necessary, in order to prevent/delay the evolution of antibiotic-resistant bacteria. I've been told that anti-fungal treatments are not a cause for concern, I.e. the strain of fungus will never build up a resistance to the treatment.
Is this true for fungi? If so, why is it true?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2oj5d4/does_fungus_build_up_a_resistance_to_treatment/
|
{
"a_id": [
"cmnrh5p",
"cmnrl8c"
],
"score": [
3,
2
],
"text": [
"What kind of anti-fungal treatment do you mean? Fungi can certainly evolve resistance to [agricultural fungicides](_URL_3_) but it sounds like you're more interested in [antifungal medication](_URL_4_) to which fungi have also evolved resistance: [1](_URL_2_) [2](_URL_0_) [3](_URL_1_). It seems as if whoever said that this doesn't occur was mis-informed.",
"I don't think there will be a correct answer without the OP providing what fungal disease he is talking about.\n\nFungi develop resistance just like bacteria do, and have been reported quite a few times. Multi-drug resistant fungi do exist as well, and have caused headaches at hospitals for some time.\n\nThe good thing about fungal drug resistance (in general), though, is that it is usually very transient. Developing drug resistance comes at the cost of resources that could have been used elsewhere. Unlike bacteria, this cost is quite substantial for fungi, so drug sensitive strains can much more easily outcompete resistant ones in normal (unsymptomatic) situations. Also, serious fungal infections disproportionately target immunocompromised people. Combine the two factors, and it is easy to see that drug resistance in fungi won't last as long or propagate as easily."
]
}
|
[] |
[] |
[
[
"http://cid.oxfordjournals.org/content/46/1/120.full",
"http://cid.oxfordjournals.org/content/36/Supplement_1/S31.long",
"http://www.ncbi.nlm.nih.gov/pubmed/22196207",
"http://en.wikipedia.org/wiki/Fungicide#Resistance",
"http://en.wikipedia.org/wiki/Antifungal_medication"
],
[]
] |
|
7qvas1
|
What is more expensive - mail or plate armour?
|
I often hear that plate armour eventually became cheaper than mail armour, but I also hear it otherwise. And as far as I can see, both sides have their arguments - but what is the truth? Did the price vary depending on your location, i.e; would plate armour in Milan or Augsburg be much cheaper when compared to plate armour in, say, England?
I'm hoping for info from the 15th century.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7qvas1/what_is_more_expensive_mail_or_plate_armour/
|
{
"a_id": [
"dssbk4d"
],
"score": [
15
],
"text": [
"At least in the Burgundian accounts, the mail armour is cheaper (in general) as the plate armour, but some very high grade mail armour could be a lot more expansive than low quality plates armour. For exemple, a full plate armour could cost between 37£ 3 s and 76£ 10s, a mail shirt, between 5£ 13s and 50£, a higher price than the lowest prince found for a full plate harness. (Those accounts spoke about livres tournoi, tournoi pounds, and not Sterling).\n\nThis variation in price is also found in the inventories of the armory of the tower of london (second part of the 14th), as Thom Richardson prouved in its thesis, where you could find mail shirts (iron) between 16s 1d and 46s 8d, and mail shirt made of steel, at the price of 4£. (Iron and steel are not always related to the use of proper steel or iron, but could aslo be use to note the quality of the armour)\n\nSources: Burgundian account, in AGR (Bruxelles) and ADN (Lille).\n\nROBCIS Dominiques, armes armures et armuriers sous le principat de Jean sans Peur (1404-1419) d'après les documents comptables, Paris, 1998.\n\nRICHARDSON Roland Thomas, The medieval inventories of the Tower armouries 1320-1410, PHD Thesis, Unversity of York, 2012."
]
}
|
[] |
[] |
[
[]
] |
|
32rvfn
|
How long does it take for a cell to travel through your body?
|
Was ready A Brief History About Nearly Everything and Bryson states that our hearts pump 1,800 gallons every day. So how long does it take for a cell to travel from my heart, to my toes, and back to my heart?
|
askscience
|
http://www.reddit.com/r/askscience/comments/32rvfn/how_long_does_it_take_for_a_cell_to_travel/
|
{
"a_id": [
"cqe32yz"
],
"score": [
3
],
"text": [
"[This page](_URL_2_) says that in a 120-day span, it will travel the body about 75,000 times. That gives you a bit over [2 minutes](_URL_0_). However, it will flow at different rates depending on the type of blood vessel it is in (see [here](_URL_3_)) and probably spends some time moving through your heart and also I think a much longer time being stored in the spleen (see [here](_URL_1_)). So, it's probably a bit less than that but of that order. Maybe someone else can provide a better estimate!"
]
}
|
[] |
[] |
[
[
"http://www.wolframalpha.com/input/?i=120+days+%2F+75000",
"http://en.wikipedia.org/wiki/Spleen#Function",
"http://faculty.stcc.edu/AandP/AP/AP2pages/Units18to20/blood/redblood.htm",
"http://en.wikipedia.org/wiki/Blood_flow#Velocity"
]
] |
|
4bxznb
|
How are multiple sounds transmitted through gases simultaneously?
|
I have seen some threads go into the specifics of sounds related to speakers. But I'm more interested in how exactly a body of gas can transmit sounds throughout its volume from multiple sources simultaneously. For example, I'm at work and can hear machines running, forklifts, people talking, radios, intercoms, etc. all at the same time. So from my perspective my ears are being bombarded by an unlimited number of sounds. Or is there a limit? I thought air molecules carried sound as they bounced off eachother and other objects. So if all these different sounds are radiating outward in spherical patterns, do they combine? cancel eachother? Is there, statistically speaking, so much more air molecules than sound sources that they can all exist at the same time, miss eachother as they travel and eventually hit my body? Just curious.
|
askscience
|
https://www.reddit.com/r/askscience/comments/4bxznb/how_are_multiple_sounds_transmitted_through_gases/
|
{
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"One way of thinking of it is that you only hear *one* sound, which is the sum of all the individual sounds. If you look at a sound waveform, it's a single line travelling up and down as air pressure changes. A steady tone has a very simple wave (a sine wave). In fact any sound can be considered to be made up of sine waves of varying frequency and amplitude.\n\nSometimes sounds do cancel each other. If you play two very close notes, for example, you'll be able to hear a \"beat\" which is the result of the two soundwaves shifting in and out of phase, alternately reinforcing and (partially) cancelling each other. Sometimes, if you're in a quiet room with, say, a whiny computer fan, you might find there are places in the room where it sounds a lot quieter than you'd expect (this will probably only happen for one ear at a time). This is where reflections of the original sound meet out-of-phase and cancel each other out.\n\nNoise-cancelling headphones work by playing the inverse of an incoming sound wave in order to (attempt to) cancel it completely.\n\nAs for how multiple sounds travel through the air, try filling a tray with water and letting drips of water fall on to it in different places. You'll see the circular ripple move out from each point. Where the ripples meet, they effectively move right through each other.\n\nHere's a very brief video showing the effect with a slinky. There are two waves, one from either end, which pass right through each other:\n\n_URL_0_\n\nAs to whether there's really a limit, I'm not sure. I suspect if you try to play too high a frequency/amplitude, other effects may take over and cause the usual addition/subtraction of sound waves in air to start breaking down.",
"The way air moves with sound is approximately linear. The change in flow is proportional to the gradient in pressure, and the change in the gradient in pressure is proportional to minus the divergence of the flow. The thing about linear differential equations is that linear combinations of their solutions are also solutions. In particular, they can be added. So if I have one sound wave that follows the laws of fluid motion and another sound wave that also follows them, then if I add the pressure and flow of both of them at each point I get another solution that's the sum of those two waves.\n\nIt's not perfectly linear, so it is possible for really loud sounds to not act quite like that, but it's pretty close. For all intents and purposes, you can have as many sound waves pass each other as you want.",
" > is there, statistically speaking, so much more air molecules than sound sources that they can all exist at the same time, miss eachother as they travel and eventually hit my body? Just curious.\n\nNo, the air is definitely dense enough for the molecules to bump into each other quite frequently. In fact, the air molecules only travel about [68 nanometers on average](_URL_0_) before hitting another air molecule. But sounds still pass through each other because the molecules getting packed tighter in one direction does not affect their ability to get packed tighter in another direction at the same time. "
]
}
|
[] |
[] |
[
[
"https://www.youtube.com/watch?v=FFUA9jbB2XY"
],
[],
[
"https://en.wikipedia.org/wiki/Mean_free_path"
]
] |
|
u4cq7
|
What is happening on the cellular level when you rub lotion into your skin, and why is it good for you?
|
askscience
|
http://www.reddit.com/r/askscience/comments/u4cq7/what_is_happening_on_the_cellular_level_when_you/
|
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"Searched a bit and found a placebo study that details some of the results of applying lotion - _URL_0_. Hope this helps!\n\n > The epidermis was thicker and papillary dermal changes included increased thickness, increased acid mucopolysaccharides, improved quality of elastic fibers, and increased density of collagen.",
"It's an assumption that it's \"good\" for you. Many people will agree that it makes you feel better when you have dry skin, but is there any other benefit health-wise? Or does it cause your body to become reliant on moisturizers rather than the skin's natural production of oils?",
"When you say lotion you can mean one of a few different things. Products known as [emollients](_URL_0_) are lipid (fat) heavy solutions that restore barrier function to disrupted skin. Another sub-class of \"lotions\" are humectants, which hydrate the skin by trapping water. Generally speaking, the lotion (vehicle) has little/no activity at the cellular level, however you do see changes in the thickness of some epidermal layers and changes in the relative proportions of components of the extra-cellular matrix. \n\nOther functions of lotions are to deliver various medications into the skin, and they're generally formulated to best serve as vehicles for the medication in a addition to being emollients/humectants. Other than that we can change qualities in the vehicle based on where on the body it will be used. Different vehicles are required for the scalp/hair, as opposed to the face, ect. ",
"NO MORE HOSE JOKES. Please. ",
"What about oil? \nLike pure coconut oil. Does that have any benefits on a cellular level?\n\nI'm a black woman and my mother has always preached moisturizing (with lotion and/or oils) my skin and that it'll prevent ashiness and prolong wrinkles. Is there any merit to this?",
"Maybe this is a good place to ask, I clicked on this link because lotion is *really* important to me - can your skin get sort of addicted to cream? I have to have hand cream with me everywhere I go - I have some in every room of the house, and it HAS to be Glysomed brand. Nothing else works, even other creams with gylcerine. If I get my hands wet and let them dry without putting handcream on, at best I feel really skeeved out by touching anything, and at worse they burn. No one else I've ever told about this knows what I mean. So, what's up with this does anyone here know?",
"A lot of people are mentioning lipid absorption into the body with lotions. One time my mom told me if I use too much lotion it'll make you gain weight. I dismissed it as crazy because she's really *quite* crazy, but now I wish to know if this is possible. Can you absorb calories from lotions? I can't find sources I'd consider meritable. ",
"So far I don't feel like anyone has answered the question satisfactorily."
]
}
|
[] |
[] |
[
[
"http://www.eblue.org/article/S0190-9622(96)80110-1/abstract"
],
[],
[
"http://dermnetnz.org/treatments/emollients.html"
],
[],
[],
[],
[],
[]
] |
||
1j72c7
|
why is it so hard to find alcohol that doesn't taste...like alcohol? you'd think someone would make a killing off of 40% koolaid-flavoured alcohol.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1j72c7/eli5_why_is_it_so_hard_to_find_alcohol_that/
|
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"You can add whatever flavorings you want, but it still has alcohol in it.\n\nThat being said, properly aged alcohols mellow out in flavor. Top shelf, 30-year-old whisky tastes nothing like a $20 bottle from Walmart. If you're really looking for something light, I would personally recommend trying Chopin Vodka or Domaine de Canton.",
"When alcohol doesn't taste like alcohol and has a more welcoming flavor, like your Kool-Aid example, nothing good would come of that night of drinking. It would possibly cause the drinker to go far beyond their limit b/c of the good flavoring and alcohol poisoning is a real thing. Straight on the rocks keeps me from drinking more than 2.",
"It's an acquired taste. Eventually, you will like the taste it alcohol, with reason. Then you won't want an alcoholic drink that doesn't taste like it. That's why they don't make it.",
"Haven't you ever heard of flavored vodka? Tastes like candy. Especially caramel vodka, thats some good stuff.",
"If you like something sweeter that doesn't taste like alcohol, but can still get you drunk, try a stronger cider! I never used to like alcohol then someone intro'd me to cider and I love the stuff! \n\nAnd if you want something stronger, find a flavoured gin, my personal favourite is sloe gin! Take a pint glass and pour about 2/3 inches of it into it, then take either lemonade or a lemon flavoured alchopop and fill the rest of the glass with it, the result is you taking around 3 shots of fairly high percentage gin whilst only tasting lemon! I used this to get very drunk, very quickly one night and lasted about 2 hours.\n\nSorry for not answering your question, just providing some alternates! :)",
"older people like tend to start liking bitter stuff over sweeter"
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[]
] |
||
33a5ua
|
does true randomness exist in the universe? if i replayed the universe exactly the same from the start, would it be exactly the same?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/33a5ua/eli5_does_true_randomness_exist_in_the_universe/
|
{
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"text": [
"We don't know, is the simple answer. Our best current guess appears to be \"yes, it does\", but there are theories that get around it at the cost of losing common assumptions.",
"Does true randomness exist in the universe?-Yes. At a quantum level randomness happens all the time. Would the universe be exactly the same if we re-ran it? Probably not, if our quantum theories are correct, although not everyone agrees. Whether we could notice the difference is anyone's guess."
]
}
|
[] |
[] |
[
[],
[]
] |
||
21e713
|
How did tribes like the Seminole in the Everglades deal with alligators?
|
I imagine living in areas that were largely swamps would mean they'd encounter them quite a bit and without guns it seems that fighting them off would be even more difficult. Maybe I'm approaching the question wrong and they had ways of avoiding them, in which case I'd be interested in how they went about that.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/21e713/how_did_tribes_like_the_seminole_in_the/
|
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"text": [
"To start out with, by the time the Seminoles started settling Florida, they already had guns. So lets turn the clock back a bit more. For thousands of years, alligators were on the menu for people living in Florida. They weren't really a common meal, of course, but their bones do show in trash middens alongside other game animals and fish. At the time of contact with the Old World, northeastern Florida and southeastern Georgia were Timucua territory. The Timucua sought out European alliances during war between the three Timucuan alliances that dominated the area. The French allied with the Saturiwa, which allowed Jacques le Moyne the opportunity to capture various aspect of Timucuan life in his art. This included an image of the Timucua preparing for a feast. [As you can see](_URL_1_), a young alligator is already cooking over the fire and another is about to be put on the rack. But those are small alligators, what about the adults? Luckily, le Moyne has an answer for that too.\n\n[In this illustration](_URL_0_), a Timucua hunting party gets an exaggeratedly large alligator to bite down on a pole (foreground), then uses the pole for leverage to flip the alligator on its back. Once it's turned over, they're able shot its softer underbelly with their bows (background).",
"Not necessarily historic, but hopefully on topic. Alligators are not particularly aggressive and rarely attack people. There were about a dozen alligator attacks in the last decade. Considering the millions of people who have contact with the creatures, this number is remarkably low. If you don't feed the reptiles or swim at dusk or in the dark, or bother them during mating season when the males are especially aggressive, alligators for the most part will leave you alone. I have been up to my armpits in Florida swamp many times in close proximity to gators and still have all my extremities.\n\nSecondly, much of the Everglades where the Seminoles live is quite shallow. In most places it is inches deep. Gators will dig holes and trench through, but it is not like the water in most places is deep enough the dangerous animals can swim up upon you undetected."
]
}
|
[] |
[] |
[
[
"http://upload.wikimedia.org/wikipedia/en/c/ce/Le_Moyne_lithograph_of_Timucua_Indians_hunting_alligators.jpg",
"http://floridamemory.com/fpc/dg/DG00984.jpg"
],
[]
] |
|
eit86m
|
how are wild plants domesticated?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/eit86m/eli5_how_are_wild_plants_domesticated/
|
{
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"text": [
"It's a very very long process, where farmers basically just breed plants with traits they like, in an effort to make those traits more prevalent over time.",
"Same as animals essentially. We find a plant with desirable qualities and then use selective breeding to essentially modify their genome into a new variety/sub-species, or a new species entirely, over time.\n\nTake your corn/teosinte example. Some time around the agricultural revolution some early human who liked to eat teosinte took some seeds and began cultivating it, propagating the plants that had the best tasting/yielding fruit. Then after a while of this selective breeding it ‘evolved’ into modern or ‘domesticated’ corn. \n\nSame as with dogs and wolves essentially. Separate a small group from the larger population and it will eventually develop distinctive traits and dna. This is the ‘theory’ of evolution."
]
}
|
[] |
[] |
[
[],
[]
] |
||
1nqm4f
|
why does my heart rate drop when i exhale?
|
I've been checking my pulse a lot lately and I just noticed this. Whenever I exhale, my heart rate plummets to like half the normal rate, then goes right back to normal when I inhale again. Why does this happen? Is this normal?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1nqm4f/eli5_why_does_my_heart_rate_drop_when_i_exhale/
|
{
"a_id": [
"ccl33dt"
],
"score": [
2
],
"text": [
"It's called sinus arrhythmia, and it's perfectly normal and benign, especially in young people. I have it too.\n \nI'm a little fuzzy on the details, but I believe it's because the expansion of your lungs as you inhale puts pressure on a nerve that controls heart rate."
]
}
|
[] |
[] |
[
[]
] |
|
3lx9ao
|
the difference between unlawful and illegal.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3lx9ao/eli5_the_difference_between_unlawful_and_illegal/
|
{
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"cva2fwk"
],
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"text": [
"They're pretty much interchangeable. You might define \"illegal\" as \"forbidden by the law\" and \"unlawful\" as \"not permitted by the law\", but they boil down to the same thing. \"Illegal\" also tends to be used more for criminal law, while a civil wrong is more likely to be described as unlawful, but that's not a clear cut rule."
]
}
|
[] |
[] |
[
[]
] |
||
2rmss0
|
lasers and mirrors
|
So mirrors are used to route laser beams. Mirrors are just reflective surfaces, like polished silver or aluminum. Can a good mirror be used to "deflect" a very powerful laser? Like super powerful ones used in crazy science labs that consume megawatts of power...are even those rendered harmless (so to speak) by a simple mirror? Is there any theoretical limit to this?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2rmss0/eli5_lasers_and_mirrors/
|
{
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],
"score": [
5
],
"text": [
"If a mirror reflects 90% if light that means it absorbs 10% of the light. If 10% of a laser is enough to burn a thing then the mirror burns. There is no 100% reflective mirrors. "
]
}
|
[] |
[] |
[
[]
] |
|
ba1c5l
|
why do home thermostats have a "heat/ cool" switch? why can't you simply set a range and have it automatically determine whether to use the ac or the heater?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ba1c5l/eli5_why_do_home_thermostats_have_a_heat_cool/
|
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"text": [
"There are actually thermostats that have an 'auto' mode that does switch from heat to cool and vice versa. Typically, only higher end thermostats have this, though. This is because it takes more advanced temperature sensors to allow an 'auto' function to work. \n\nSay it's summer and you have the thermostat set to 'cool', and 78 degrees. The AC blows cool air into the house, but it might reduce the temperature to 77 degrees. This is typically intentional, to increase the time between the system turning off, then on again as the temperature rises from outside heat. In this case, if you were in an 'auto' mode, the furnace would kick in, which would not be desirable in the summer! \n\nPremium thermostats that do have an 'auto' switch for heat and cool have extra setpoints or criteria before allowing the system to shift modes. For example, some use the date to determine what month it is, to prevent the furnace from being used in the summer. Otherwise, it would be 'turn AC on if temperature hits 80F, and furnace if it hits 70F' or something like that. ",
"Simple reason, it is a cheaper model. My thermostat has an auto setting where I can set a high and low. Depending on the temp it will kick on heat or ac to stay in the proper range.",
"I have a Honeywell thermostat with an auto function. It allows a range of temps and will automatically switch from heat to cool. However, I find that even with the minimum spread of temperature allowed by it, the temperature swing is too much for me to be comfortable. So I still use it manually.",
"Because most people want different set points. For example you might want to heat (up) to 20°C and cool (down) to 26°C. Between those two points you want neither cooling nor heating."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
2qc1jz
|
why are data caps for mobile phones still so small?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2qc1jz/eli5_why_are_data_caps_for_mobile_phones_still_so/
|
{
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"text": [
"Phone companies are greedy so they set data limits low to either a) make you use less of their product than you normally would or b) pay more for using your natural level of usage.",
"For those using t-mobile and are paying at least 3gb data monthly, u should be able to carry over your unused data for the next month. Not sure if it started now or at a given time, I'll pull the text that they sent me... ",
"This ELI5 may shed further illumination, especially if you are comparing home plans to mobile. _URL_0_",
"Lack of competition in the marketplace. Behemoth corporations have taken over and the incentives for innovation go down.",
"The reason the data cap on your plan is so small is that you purchased a plan with a low cap.",
"It's an arbitrary number. Similar to the number of letters in an SMS message.\n\nThe concept of a 'data cap' is meant to limit the quantity of data that flows through a network, but that's not really how networks work. Networks send data to a destination, then forget about the data. That destination may be a temporary storage server if your phone is off or something, but it is still a destination. \n\nWhen you're downloading something over your phone (like this reddit thread) your phone requests the data from the server, and the server spits it back at your phone. Done. Boom. You have what you wanted, the network moves onto something else.\n\nNetworks have a data capacity, but this is not a *storage* capacity, this is a *transmission* capacity. A typical sleepy township cell tower will have at least a gigabit [backhaul](_URL_15_) connection to the network provider so that it can provide cell service. When you try to download something you use up a bit of that bandwidth.\n\nRemember, it's not a big truck. [It's a series of tubes.](_URL_11_) As you use the tube, it fills up. Everyone uses the tube? Tube's full, new requests have to wait until there is space in the tube. Instead of getting a message saying \"Tube's full bro, wait a bit\" the network will slow everyone down a bit to cram your request into the pipe.\n\nNow, instead of a sleepy little town let's talk about New York City. If we look[ into the books of not-too-distant history](_URL_10_) we will remember that [AT & T had a bit of a problem when the iPhone](_URL_7_) was [unleashed upon their networks.](_URL_5_) Suddenly, people were sharing *pictures* and *videos*! They were browsing the *internet* and they weren't business customers!! Madness roaming about the streets! And, most importantly, their network **was not prepared for this**.\n\nDemand was unprecedented and their network was rapidly brought to its knees in major cities. As they threw everything they had at the major cities the local towns began to suffer too. Major networks got everything situated for the time being, but they're still playing catch-up in a lot of areas.\n\nSo now that the iPhone is out and about everyone is filling the tubes all the time always. [New York Times chimed in](_URL_14_) with a lovely long article really detailing the issue, and there were other companies suggesting that consumers [do the responsible thing and control their data guzzling.](_URL_0_) Use WiFi when watching YouTube, for instance.\n\n(Side note: I just want to point out a **lovely** quote from that NYT article: \n > The company has also delayed bandwidth-heavy features like multimedia messaging, or text messages containing pictures, audio or video. It is also postponing “tethering,” which allows the iPhone to share its Internet connection with a computer, a standard feature on many rival smartphones. AT & T says it has no intention of capping how much data iPhone owners use. \n\nOf note this was actually one of the first big intentional violations of net neutrality. A system called Quality of Service, or QoS, was used to make raw data, emails, etc. more important to the network than multimedia (music, youtube) on the network. This helped, a bit, somewhat, because important emails could get through when too many people were watching cat videos in wifi-less coffee shops. The line about not capping data actually plays right into what I'm talking about)\n\nNow, what do we do about this? Well, AT & T introduced [QoS](_URL_13_) and data priority, which let important things through when the tubes were full of unimportant traffic. This somewhat helped people get work done, but the root issue was the tubes were full and it was [expensive to put new tubes out there.](_URL_2_)\n\nNow, where did the caps come from?\n\nWhile networks do not store, they do have quantities transferred. You see this as a 2GB cap on the data you can use in a month. AT & T sees this as 1 cent per Terabyte transmitted to Cogent. That's an extremely simplified [peering rule](_URL_6_), but it works for this discussion. In order to talk to someone's server that is on Cogent's network when you're on AT & T's network, at some point along the line your data needs to go from one network to another. That's peering.\n\nSometimes this peering is free (like Cogent). Sometimes this peering is not (like Verizon, I think). When it is not, it costs the company money to transmit data that direction.\n\nSo the network providers already have a concept of paying for data transmission rates. They pay each other for data going back and forth (called transit), this is not a new concept. Originally you could get data modems for the early cell networks, and you paid per *kilobyte* and later megabytes. [Satphones will still do this.](_URL_12_) So the raw idea of \"pay for a block of data\" was something that the telcos were already familiar with. \n\nThat's where the idea *came from*, but *why*? Well, they needed to reduce network load. \n\nIf you want to reduce network load then you throttle network connections. Block multimedia due to \"heavy load\" during peak hours, maybe do some on-the-fly calculations on what the network can handle and modify what people are allowed to connect to on the fly. This makes for *extremely* pissed off users. A slowly loading website is one thing, \"Cannot load: Network capacity reached\" is another thing entirely. So that's out as a solution. Temporary at best.\n\nNext up is tiered access. Pay for Facebook, Twitter, etc. at one rate, and at the next rate get access to YouTube etc. Violates net neutrality and gets the FCC up your butt. That's out.\n\nIncentive wifi use. Your average smartphone user doesn't really care (unless they're watching their data use closely) where their data comes from, so you need to make this an incentive. Generally, plans will let you make \"FREEEEEEEEEEEEEEEEE\" calls over wifi and of course free data these days. Most phones have an ability to constantly seek, connect to, verify connection through and then use any available wifi networks with open internet. This can cause problems (\"Why is my call dropping when I walk past this coffee shop all the time?\") but also gets people who don't care and don't watch their phone's wifi connection to get the hell off your wireless network when they want to watch a stupid puppy. This took a few years to implement, but it's what they're doing now.\n\nForce people to care about how much data they use. Thiiiiisss is where the caps originally came in. Some manager somewhere asked the sysops \"Wtf do we do about all of these youtube videos!?!\" and the sysops replied \"Uh, block youtube.\" Management vetoed this because the big selling point was cat-videos-on-the-go right in your pocket.\n\nSo then they said \"[Wait, we could just introduce a data cap.](_URL_8_)\"\n\nHaving something be unlimited makes you not care about it. Having a resource be limited (scarce) makes you preserve it. Having it be an *allowance per month* makes you budget it, and having it be expensive when you go over (or throttle to shit, like T-Mo) makes you want to not go over.\n\nThis means you smear your 5GB (or 2GB, or 4GB, etc) out over the course of a month rather than just watch youtube videos on the bus every day.\n\nNow read this [Bloomberg BusinessWeek article](_URL_1_) about it. Here's a BoingBoing article from a similar time period. Listen to how *happy* they sound about this idea. Data caps were a financial incentive to use significantly less data, and at the time people did use significantly less data. Note how there's no mention of actual data amounts anywhere in those articles? Back in 2009 the average iPhone user[ used 400 Megabytes of data a month,](_URL_3_) compared to other \"[smartphones](_URL_9_)\" of the time period using closer to 80 MB a month.\n\nThese days that's *nothing*. You can eat through 80 MB on a single day with a few youtube videos, some Reddit image browsing and a little bit of MMS images shooting back and forth. I'm on Sprint, and last month I used north of 15 GB of data. It's easy to do in our high resolution always connected world these days. Back then, it was a non-issue.\n\nThe Slate article I posted earlier is talking about $10/100MB. That'd be madness in our day and age ($200/2GB) so we're pretty happy when they ask for less than 50 bucks a month for this generous 2GB package. In [2010 AT & T released their tiered data structure](_URL_4_) which was the genesis of the current 2GB trend in wireless plans. Then they sunsetted the unlimited plans. Now, people were monitoring their data use, badgering their coffee shops to install wifi and generally giving the internet tubes significantly less of a beatdown. This helped, and today NYC has wireless coverage that isn't completely terrible.\n\n(Cont)",
"Because people happily pay for it.\n\n\nThey may use the \"we can't have everyone maxing it or nothing would work\" excuse."
]
}
|
[] |
[] |
[
[],
[],
[
"https://www.reddit.com/r/explainlikeimfive/comments/2pnw7a/eli5_why_are_there_unlimited_data_home_internet/"
],
[],
[],
[
"http://www.maclife.com/article/feature/iphone_app_data_hogs",
"http://www.businessweek.com/technology/content/may2009/tc20090515_773194.htm",
"http://www.att.com/gen/press-room?pid=4800&cdvn=news&newsarticleid=27069",
"http://usatoday30.usatoday.com/tech/news/2009-06-16-iphone-att-3gs_N.htm",
"http://www.att.com/gen/press-room?pid=17991&cdvn=news&newsarticleid=30854&mapcode=",
"http://www.technologizer.com/2009/06/09/atts-network-problems-arent-just-in-big-cities-anymore/",
"http://en.wikipedia.org/wiki/Peering",
"http://www.slate.com/articles/technology/technology/2009/10/the_iphone_is_not_an_allyoucaneat_buffet.html",
"http://appleinsider.com/articles/09/05/18/repeat_att_may_introduced_20_limited_iphone_data_plan",
"http://en.wikipedia.org/wiki/BlackBerry_Bold",
"http://www.applegazette.com/iphone/the-iphone-is-useless-in-new-york-city/",
"https://www.youtube.com/watch?v=f99PcP0aFNE",
"http://en.wikipedia.org/wiki/Iridium_Communications",
"http://en.wikipedia.org/wiki/Quality_of_service",
"http://www.nytimes.com/2009/09/03/technology/companies/03att.html?_r=1",
"http://en.wikipedia.org/wiki/Backhaul_%28telecommunications%29"
],
[]
] |
||
4xe0lq
|
Does the wobble of our sun caused by Jupiter's gravity effect the weather on Earth?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4xe0lq/does_the_wobble_of_our_sun_caused_by_jupiters/
|
{
"a_id": [
"d6ftma4"
],
"score": [
3
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"text": [
"Jupiter's gravity does affect the climate on Earth but it's over many thousands of years. The variations in Earth's axial tilt, orbital obliquity, etc caused by Jupiter are called the Milankovich cycles and are associated with ice ages. As for the 12 year orbit of the Sun/Jupiter system...the 11 year sunspot cycle likely has a larger effect, especially because the sun doesn't move that much compared to Earth's ellipiticity."
]
}
|
[] |
[] |
[
[]
] |
||
1dutm8
|
How different is breast milk to formula in terms of the baby's health?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1dutm8/how_different_is_breast_milk_to_formula_in_terms/
|
{
"a_id": [
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"c9u85sh",
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"text": [
"Please remember that this is /r/askscience. While it may be tempting to share your own experiences as a parent, this forum is for a discussion of science. **Please refrain from sharing your own experiences or speculation/guesses.** \n\nThere is a lot of research on this topic, so please make sure to use scientific sources (not popular media articles or parenting websites). \n\nThanks, have a wonderfully scientific day!",
"I've seen numbers that kids are 60 - 80% less likely to have SIDS if given breast milk. \n\n_URL_0_\n\n_URL_1_\n\nSo... at least that different.",
"In some cases up to 30% of cells in breast milk are stem cells, which in primate trials have been found to enter the bloodstream. _URL_0_\n\nSo that's a pretty big difference.",
"A colleague of mine studies the ability of breast milk antibodies to protect children from enteric infections. Breast milk contains a lot of IgA (a particular kind of antibody) which has been shown to protect against parasitic infections like Cryptosporidiosis. \n\nThis particular aspect of breast milk may not be so important for kids growing up in the first world, but frequent diarrheal disease in third world countries causes a lot of growth and cognitive issues for children, and can even reduce their ability to respond to important vaccinations (i.e. polio). ",
"[Colostrum](_URL_1_) is especially important:\n\n > Newborns have very immature digestive systems, and colostrum delivers its nutrients in a very concentrated low-volume form. It has a mild laxative effect, encouraging the passing of the baby's first stool, which is called meconium. This clears excess bilirubin, a waste-product of dead red blood cells, which is produced in large quantities at birth due to blood volume reduction, from the infant's body and helps prevent jaundice. Colostrum is known to contain immune cells (as lymphocytes)[4] and many antibodies such as IgA, IgG, and IgM. These are the major components of the adaptive immune system. Inter alia IgA is absorbed through the intestinal epithelium, travels through the blood, and is secreted onto other Type 1 mucosal surfaces. Other immune components of colostrum include the major components of the innate immune system, such as lactoferrin,[5] lysozyme,[6] lactoperoxidase,[7] complement,[8] and proline-rich polypeptides (PRP).[9] A number of cytokines (small messenger peptides that control the functioning of the immune system) are found in colostrum as well,[10] including interleukins,[10] tumor necrosis factor,[11] chemokines,[12] and others. Colostrum also contains a number of growth factors, such as insulin-like growth factors I,[13] and II,[14] transforming growth factors alpha,[15] beta 1 and beta 2,[16][17] fibroblast growth factors,[18] epidermal growth factor,[19] granulocyte-macrophage-stimulating growth factor,[20] platelet-derived growth factor,[20] vascular endothelial growth factor,[21] and colony-stimulating factor-1.[22]\nColostrum is very rich in proteins, vitamin A, and sodium chloride, but contains lower amounts of carbohydrates, lipids, and potassium than normal milk. The most pertinent bioactive components in colostrum are growth factors and antimicrobial factors. The antibodies in colostrum provide passive immunity, while growth factors stimulate the development of the gut. They are passed to the neonate and provide the first protection against pathogens.\n\nFormula contains more iron than breast milk - however, a newborn typically has enough iron stored to last them for the first six months postpartum, so supplementation is not necessary before then.\n\nIf formula is used to supplant breastfeeding, then the mother tends to cease lactation sooner than had she employed breastfeeding exclusively.\n\n > [Breastfeeding](_URL_0_) also provides health benefits for the mother. It assists the uterus in returning to its pre-pregnancy size and reduces post-partum bleeding, as well as assisting the mother in returning to her pre-pregnancy weight. Breastfeeding also reduces the risk of breast cancer later in life.[13][14]\n\n-edit\n\nAdded additional link.",
"Breast milk contains human milk protein, which is much easier for brand new infants to digest than the bovine milk protein used in most formulas. Most importantly, the human breast secretes a product called \"collostrum\" in the first few days of life. Collostrum is filled with antibodies, which the mother needs to transfer to the infant in order for him or her to gain immunity to many common pathogens. Immunoglobulin G is the only type of antibody that easily crosses the placenta, and the other four types must be transferred through collostrum.\n\nFrom a developmental perspective, the act of breastfeeding itself is seen to be very important to secure mother-child attachment. The skin-to-skin contact between mother and baby in the early stages of life is so important, that we will actually place the baby on his or her mother's chest immediately after birth, before even clamping the cord if possible.\n\nNo online sources, just my obstetrical nursing textbook:\nPerry, Shannon E. (2013). *Maternal Child Nursing Care in Canada.* Toronto: Elsevier.",
"Are you asking:\n\n1. How does the composition of breast milk differ from formula?\nor\n2. What are the differences in health outcomes between infants fed formula versus breast milk?",
"Formula milk is associated with infant weight gain significant enough to require a separate growth chart from infants who are breast fed.\n\n_URL_0_",
"[This](_URL_0_) suggests that the \"human milk microbiome\" changes over the course of lactation. So, as a breastfeeding baby ages, s/he is exposed to different bacteria. \n\nFormula does no such thing, and I'm guessing is typically devoid of bacteria altogether. The question, then, is whether or not exposure to a diverse microbiome is healthier than the other option. Surely someone here can answer that?",
"I'm not an expert in this topic, but seeing as there's a significant lack of scientific sources posted so far in this thread, I thought I could at least put my research media to good use! Feel free to add any useful sources you can find!\n\nFrom the American Journal of Clinical Nutrition, [this study](_URL_1_) is an analysis of research done on the effect of breastfeeding on cognitive health: Found higher cognitive function in breast-fed children than in formula-fed children from 6-23 months of age. Low-weight infants saw the most distinction (premature babies benefit from breastfeeding more than average weight babies). Note this is from 1999, I'm certain there are more recent studies.\n\nFrom NIH, [this study](_URL_0_) (PDF), concluded that babies breastfed for more than 13 weeks had significantly fewer gastro-intestinal infection and also significantly (but less so) fewer respiratory infections. Babies breastfed for less than 13 weeks were similar to those bottle-fed.\n\nAlso from NIH, [this study](_URL_3_) found no correlation between breast-feeding and intelligence of the child (after the intelligence of the mother was accounted for, mothers with higher IQ were more likely to breast-feed).\n\nFinally, from Pediatrics (official journal of the American Academy of Pediatrics), [this study](_URL_2_) determined that breast-fed children were less likely to die in the postneonatal period and longer periods of breastfeeding continued to decrease that risk.\n\nAgain, I am not an expert and simply posted the information that I could find full-text available research for.",
"Excellent question! And, as with most excellent questions, the results are controversial (well, not much controversy in the scientific and pediatric community, but in the public at large).\n\nWhile there are minor differences in nutrient supplementation between formula and breast milk, and there are supposedly differences in terms how breast milk changes to fit the baby (breast milk produced to feed a 1-month old may be different from breast milk produced to feed a 6-month old), the largest difference seems to be related to the baby's immune system. Babies are naturally born with very immature immune systems, and they are susceptible to a host of various diseases! Nowadays, we often vaccinate our babies, but vaccination can be incomplete and starts much later than the baby starts being vulnerable (ie, from birth). Breast milk can help the baby's immune system fight off any infections in the short term as well as train the immune system to deal with infection later!\n\nThe other \"immune-related\" difference that's become popular recently is that breast milk can direct how the baby's gut bacteria develop! It's definitely true that breast milk and formula, though they may be calorically similar, have different types of sugars, which means they encourage different kinds of bacteria to grow and survive in the gut. There are also studies indicating that there are other molecules in breast milk (like hyaluronan) that direct gut bacteria in a certain way! This could be important for preventing a variety of different diseases, just by encouraging the so-called \"good\" bacteria.\n\nI'm sure there are other differences, but those are the two that stand out the most to me!"
]
}
|
[] |
[] |
[
[],
[
"http://www.webmd.com/parenting/baby/news/20110613/breastfeeding-cuts-sids-risk",
"http://www.sids.org/nprevent.htm"
],
[
"http://www.newscientist.com/mobile/article/mg21729084.800-are-breast-milk-stem-cells-the-real-deal-for-medicine.html"
],
[],
[
"http://en.wikipedia.org/wiki/Breast_milk",
"http://en.wikipedia.org/wiki/Colostrum"
],
[],
[],
[
"http://www.ncbi.nlm.nih.gov/pubmed/9691152"
],
[
"http://ajcn.nutrition.org/content/96/3/544"
],
[
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1661904/pdf/bmj00160-0017.pdf",
"http://ajcn.nutrition.org/content/70/4/525.full",
"http://pediatrics.aappublications.org/content/113/5/e435.full",
"http://www.bmj.com/content/333/7575/945.pdf%2Bhtml"
],
[]
] |
||
c562rv
|
Rhodesia & NIBMAR
|
Was the NIBMAR a tale of Britain trying to maintain control over Rhodesia and delay its independence, or a genuine attempt to tackle racism and discrimination?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/c562rv/rhodesia_nibmar/
|
{
"a_id": [
"es10lut"
],
"score": [
5
],
"text": [
"The policy of 'No Independence Before Majority Rule' came out of the September 1966 meeting of the Commonwealth of Nations. At that meeting, Commonwealth members from the Caribbean, Asia and Africa (minus Southern Rhodesia) caucused together and proposed that the Commonwealth position should be No Independence Before Majority Rule. East African leaders like Milton Obote, Jomo Kenyatta and Kenneth Kaunda were particularly prominent in pushing this position, as they had already met in Dar es Salaam in Tanzania to articulate a unified strategy prior to the opening of the Commonwealth meeting.\n\nOn the other hand the UK, Australia and New Zealand formed a bloc resistant to NIBMAR. British PM Harold Wilson had previously been engaged in negotiations with Ian Smith that established a formula for independence, and was resentful at being forced to backtrack from those negotiations. Wilson proposed to the commonwealth a phased plan where UK would engage in another round of negotiations with Smith, and if Smith remained intransigent on points of contention, UK would end negotiations and _then_ support NIBMAR.\n\nIn between these two blocks was the government of Canada which sought to build a consensus between the two factions, and Harold Wilson gave Canadian PM Lester Pearson the task of writing a compromise draft communique that would present a consensus Commonwealth position on the Rhodesia issue. Pearson's compromise draft included NIBMAR as \"the demand of a majority of the Commonwealth\". Pearson's draft was ultimately adopted by the meeting.\n\nSo, NIBMAR was *not* a British attempt to maintain control over Rhodesia, it was a position articulated by African heads of state and forced on UK by diplomatic pressure.\n\n----\nSource\n\n[UDI: The international relations of the Rhodesian Rebellion](_URL_0_) by Robert Goode, pp 170-177"
]
}
|
[] |
[] |
[
[
"https://books.google.com/books?id=o3R9BgAAQBAJ&printsec=frontcover#v=onepage&q&f=false"
]
] |
|
5hxnnh
|
Is analytic continuation of the Riemann-Zeta function more than just a reflection over a vertical line?
|
Watching [this](_URL_0_) video of an animation showing how to think about the Riemann-Zeta function geometrically, I am left with the impression that the Analytic Continuation of the function is just a reflection. Please tell me how I am wrong.
|
askscience
|
https://www.reddit.com/r/askscience/comments/5hxnnh/is_analytic_continuation_of_the_riemannzeta/
|
{
"a_id": [
"db3xsri"
],
"score": [
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"text": [
"It's almost a reflection about the line Re(s)=1/2 (the critical line), but not exactly. If it were a reflection, then if s were a point to the left of this line, its value there would be equal to the value of the point exactly opposite on the right side of the line, and this point is 1-s. That is, we would have Z(s) = Z(1-s). But this isn't exactly what happens. In reality we have\n\n* Z(s) = Z(1-s)\\*2^(s)pi^(s-1)sin(pi\\*s/2)Gamma(1-s)\n\nSo there is an extra scaling factor in there, and this scaling factor can make it totally look not like a reflection (see [this](_URL_0_)) However, this extra scaling factor is in there because the Riemann Zeta Function is actually \"incomplete\". We can construct the Riemann Zeta Function for Re(s) > 1 either by the sum of 1/n^(s) for n=1 to infinity, or we an do it as the product of (1-p^(-s))^(-1) over all primes p. This is the [Euler Factorization](_URL_2_) of the Riemann Zeta Function. When viewed this way, the product in the Euler Factorization is actually missing a contribution from a prime. The \"Prime at Infinity\".\n\nIn their natural state, the Rational Numbers do not live on a line, they're just a pile of fractions that we can add/multiply together. But, if we put them on a line ordered by their absolute value, then we find that there are holes in this line, tons of holes. By filling in these holes, we are able to construct the Real Numbers. So we get the real number system by 1.) Applying a geometry to the rational numbers and then 2.) Filling in the holes left by this geometry. It might then be natural to ask \"Are there *other* geometries we could apply to the rational numbers that result in a *different* number system in a similar way?\"\n\nIt turns out that the answer is \"Yes!\" If p is a prime number, then I can say that N is *p-adically* smaller than M if p divides M more than it divides N, and write this as |M|*_p_* < |N|*_p_*. For example, |50|*_5_* < |49|*_5_* and |16|*_2_* < |8|*_2_*. This can also be extended to fractions, where if the denominator has a p in it, then that takes away from the count. So |5/16|*_2_* > |5/8|*_2_* since 2 divides the bottom more in 5/16. This gives us an alternate geometry to arrange the rational numbers, and this geometry will be nicely behaved and have holes in it, just like when we put it on the line. If we fill in these holes, then we'll get a new number system that was constructed in the same way as the real numbers were constructed, just with a different geometry. These are the [p-adic Numbers](_URL_1_), and there's a different one for every prime p.\n\nSo using the same method, we can make the real numbers and the p-adic numbers (for each prime p). These should be thought of as siblings in a big family, where the reals are the odd one of the bunch. It then turns out that the reals+p-adics are the *only* number systems that can be made in this way. It then seems like the \"Reals\" should be included as a \"prime\" since it kinda behaves similarly to the primes in this way. We then say that the reals are the \"Prime at Infinity\" (which is a term we borrow from geometry). This \"Prime at Infinity\" doesn't have a number associated to it, but it behaves like primes in pretty much all other ways. \n\nSo, back to the Riemann Zeta Function. With this in mind, the Euler Product for the Riemann Zeta Function takes into account all the primes, except the reals. It seems like the reals are then a missing from the Riemann Zeta Function. In fact, we can view the term (1-p^(-s))^(-1) that appears for the prime p in the Euler Factorization as a specific kind of integral over the p-adic numbers and we can actually construct an analogous integral over the reals. The value of this integral will be 2^(-1)pi^(-s/2)s(s-1)Gamma(s/2) and if we append this to the Euler Factorization we get what is called the \"Completed Zeta Function\", Xi(s). The analytic continuation of *this* function is just a simple reflection:\n\n* Xi(s) = Xi(1-s)\n\nThis follows from the above expression + properties of the Gamma function.\n\nNote: This isn't how the Completed Zeta Function was originally made. Originally, we just used a trick involving a change of variables in an integral to recover the Zeta Function from the integral expression for the Gamma Function, and it is this that allowed us to get the analytic continuation in the first place. This transformation hinted at what Xi(s) should be, so we used that. The whole \"prime at infinity\" concept is a relatively modern idea."
]
}
|
[] |
[
"https://www.youtube.com/watch?v=sD0NjbwqlYw"
] |
[
[
"https://www.wolframalpha.com/input/?i=Zeta%5Bs%5D",
"https://en.wikipedia.org/wiki/P-adic_number",
"https://en.wikipedia.org/wiki/Riemann_zeta_function#Euler_product_formula"
]
] |
|
3ojtxw
|
what do underwriters for insurance companies do?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3ojtxw/eli5_what_do_underwriters_for_insurance_companies/
|
{
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"text": [
"Underwriters are the people actually taking on responsibility for the insurance claim; the people who will actually pay. \n\nIn a lot of cases this is the same company, but if for instance you use an insurance **broker**, that's where things would be different, because they would search around for the best company for whatever it is you need, and choose them on your behalf. \n\nSay for example you use the insurance broker, \"No Crash Insurance\". They might shop around and find the best deal for you is with \"Union Direct\". In case it wasn't obvious, these names are made up for the purposes of this example.\n\nIf you accpted that, then your insurance would then be through \"No Crash Insurance\", underwritten by \"Union Direct\".\n\n"
]
}
|
[] |
[] |
[
[]
] |
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