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10g9uf
|
how does a random function work?
|
If a random function is made up of a certain algorithm, you'd surely be able to somehow calculate it, wouldn't you?
Also, wouldn't it simply repeat itself after a while?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/10g9uf/eli5_how_does_a_random_function_work/
|
{
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"c6d7kix",
"c6d7mpe"
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"score": [
2,
11
],
"text": [
"Before a matematician/IT guys confirms it, I can say that it takes a really difficult to foresee value (ex. the actual date, up to the hundredth of second) and feed its to a very complex function whose output is even harder to foresee, and has an uniform distribution in a given interval.\n\nEx. get date, divide for hundreth of second, square root the value, take the 62th and 103th digit after the dot and multiply, blah blah blah..\n\n",
"A random number generator like the one typically used by a computer to generate random numbers isn't actually random. It is what is known as a *pseudo-random number generator*. It generates numbers according to a certain algorithm that first is initialized with a value called *seed*. For different seed values, different pseudo-random sequences would be produced. Your computer will usually use something like the current time as seed to initialize the pseudo-random number generator. And then you get these pseudo-random numbers that seem to be random, even if they aren't. For most purposes, this is good enough.\n\nA certain category of pseudo-random number generators are known as *cryptographically secure pseudo-random number generators*. These are algorithms that conform to certain requirements that are hard to ELI5, but the basic and most important idea is that one can't predict what the next number would be even if you know the entire sequence up until now.\n\nFor certain applications where truly random numbers are needed, special hardware devices are used that can generate random numbers by using physical processes that are unpredictable (random) by the laws of physics."
]
}
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[
[],
[]
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cj0otb
|
why can some brands completely rip off other brands designs on certain products?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/cj0otb/eli5_why_can_some_brands_completely_rip_off_other/
|
{
"a_id": [
"evaec1l"
],
"score": [
3
],
"text": [
"Per a quick google search, they are often lawsuits for this. However, I’d hazard a guess that court costs and lawyer fees are factored in before moving forward. Generic copy at Walmart maybe only profits 40k$, but the lawsuit would cost 200k for both sides. It’s now a loss to sue and not worth moving forward. Adidas sued Walmart for infringing on their 3 stripe design a while back and won. Those shoes now have 4 stripes.\n\nEdit:changed a letter"
]
}
|
[] |
[] |
[
[]
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dkh7xr
|
does convolution of signals have an intuitive explanation like the water-flow example for voltage and current?
|
I understand convolution from an equation point of view but is there some way to visualize it easily? something similar to the water flow in a pipe example for current through a wire.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/dkh7xr/eli5_does_convolution_of_signals_have_an/
|
{
"a_id": [
"f4f0ure"
],
"score": [
2
],
"text": [
"Have you heard of convolution reverb?\n\nBasically, you take an impulse response from, say, a cathedral, and then you can convolve it with any sound signal to make it sound as if it were in the cathedral.\n\nSo i guess a convolution is kind of like an echo. A bit like sonar - when there is something x-metres away, you'll get a corresponding spike on the impulse-response when the echo comes back."
]
}
|
[] |
[] |
[
[]
] |
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89pr9h
|
the definition of “literary theory”
|
The definition is kind of confusing for me to understand so I was wondering if you lot could explain it to me differently? Thanks!
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/89pr9h/eli5_the_definition_of_literary_theory/
|
{
"a_id": [
"dwskrfl"
],
"score": [
3
],
"text": [
"I suppose there isnt one definition but a literary theory woukd be a way in which yoi can understand/interpret literature. \nFor example you could read a text in a feminist or post colonial way and theyre both literary theories. \nOr you could theorise on what literature itself is, for example literary theorist Roland Barthes discusses the role of the author in literature."
]
}
|
[] |
[] |
[
[]
] |
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26k5hi
|
Mistakes Germany made on Russia
|
Hey, can someone explain Germany's mistakes in Russia and the ways it affected the outcome of the war? I know they underestimated Russia's power, and weren't ready for the cold climate, any others? Could you give links (just so i can go ahead and read more by myself).
Thanks in advance!
Cheers!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/26k5hi/mistakes_germany_made_on_russia/
|
{
"a_id": [
"chrt58h",
"chru2yb"
],
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10,
266
],
"text": [
"There are two problems, I think, with the German War in the east. 1) the Germans, due to the racist Nazi ideology, was far too brutal against the Slavic nationalities in the conquered territories. 2) The size and scale of Russia made a rapid victory like in 1940 virtually impossible. \n\nTo point 1), Hitler famously said that his first attack would wreck the fragile Soviet state. He was alluding to the many national and racial minorities which the Russians dominated. This included Hungarians, Poles, Finns, Baltics, Siberians, Asians, Arabs, and a myriad of other ethnicities. Famously, the Ukrainians welcomed the Germans with open arms in the first weeks of Barbarossa. But, rather than courting dissident groups and promoting revolt behind Soviet lines, the Germans instead implemented a large scale program of harassment and extermination. This news was carried rearward by the retreating Red Army, and by Winter of 1941 any possibility of counter-revolution had been killed. Instead, Russians and non-Russians unified to defeat the barbaric Nazi menace. It was a major opportunity which the Germans wasted. \n\nTo point 2), the Germans had grown used to quick victories. In 1940, they had smashed the French Army, destroyed the cohesion of its armies, and quickly occupied regions of critical importance to French government (like, say, Paris). But Russia was big, and even if the German army achieved smashing success, it would never reach Moscow and St. Petersburg (Leningrad) as quickly as it did Paris. The distances are simply not comparable. Instead, the German army focused on destroying the Red Army along the border. It makes sense, if the Red Army was destroyed in Soviet Poland, who would stop the Germans from taking Moscow? Nobody, thats who. *But* it wasnt that simple. The Germans were really good at destroying an enemies *cohesion*, or its ability to operate effectively. But it had a harder time destroying the Russian army. Again, the spaces involved (and especially the unit density, or the average number of men per km) were so great that while Russian Corps and Armies were destroyed, many men simply passed through the porous German lines. They would later reform into new units which would defend Moscow. Its hard to say how the *Wehrmacht* could have solved that glaring issue, but it was a major cause for their defeat. Russia is just so big, and the Germans were totally unable to account for that.\n\n",
"Wall of text- I'm sorry but it's a really complex answer that I've already really pruned down.\n\nI'm going to direct your attention to a frequently underappreciated aspect of the historiography- differing conceptualisation of warfare at an operational level. Under appreciation for this level of history stems from a Western lack of appreciation of it's intricacies, and an often excessive reliance upon German Generals and sources who sought to rationalise their defeat in the terms of tactics and strategy- simply put, they argued that German generals and armies were constantly tactically superior to their enemies, and Hitler is responsible for all strategic mistakes. This rather conveniently ensures former German generals were freed from having to admit they made mistakes, and allowed them to keep their lucrative lecturing tours. that the German army deployed a somewhat complex operational method at this time was conveniently forgotten.\n\n'the Wehrmacht is generally portrayed as immensely superior in every aspect...its failure are ascribed to adverse climatic conditions, the sheer size of the USSR, overwhelming soviet numbers, hitler's mistakes...everything...except superior Red leadership and combat performance.(1)'\n\nFollowing the end of the first world war and the Russian civil war, Stavka (the Russian high command) recognised that the traditional division of warfare between tactics and strategy was outdated, and that a gap existed between these. Tactics had come to be associated with divisional combat downwards, while strategy was a question of Army Groups and High Command. Operational level technique exists in this gap, and the relationship between all of these levels is implicitly interlinked as it's first proponent, Aleksandr Svechin pointed out 'tactics make the steps from which operational art leaps; strategy points out the path.' The operational level of warfare deals with this path, and is best described as being\n\n'Concerned with the disruption of the enemy's overall cohesion on a large scale, preventing him from accomplishing his aims and breaking up his organisation and control of higher formations. destruction of large enemy groupings is achieved as a result of the disruption of his plans, timetabled and ability to organise over a wide area and in great depth (i.e. 300-500KM).(2)'\n\nThese concepts were outlined initially outlined in the Russian manual PU-36 (field manual-'36) and detailed two key concepts, deep battle, and Maskirovka. The great purge (or as the Russians prefer to call it 'the events of 1936-8') saw the rejection of these ideas for a more traditional approach, but they were rapidly re-introduced with PU-42. Maskirovka is a term describing camouflage, concealment, deception, signals counter-intelligence and surveillance methods and has no accurate English translation, just note that it was the means by which the Russians aimed to achieve surprise, and that Russian doctrine views the surprise as a 10X force multiplier- one man with it, is worth 10 without.\n\nDeep battle was a term utilised to describe what we would call blitzkrieg, but carried out on a far larger scale. A Russian Army group (called a 'front') would be devided into two unequal halves. the first, representing 1/3 was called a pinning group, and was responsible for holding the frontline when it was static, carrying out spoiling attacks etc. this allowed for the major concentration of resources into 'strike groups,' representing 2/3 of the forces deployed. these were divided into shock armies and mobile groups\n\nShock armies were essentially break-in formations, heavily provided with infantry support tanks, engineers and artillery. they would punch a hole in the initial defences through overwhelming concentrations of force and firepower.\n\nthese openings would then be exploited by mobile groups- composed of tank armies equipped with anti-tank guns, mechanised infantry, self propelled guns and medium tanks such as the t-34. these would develop the break-in into a break out and exploit deeply. \n\nIt is important to understand the scale of these operations, and the interlinking of them. A series of shock armies would engineered several break-ins of about 12-15 km width, with about 16-20km between each of them. These break-ins would have a depth of about 10-15 km, which would then be rapidly exploited by the mobile groups, sacrificing some combat power to complete the break out. These formations were then expected to drive deeply to a depth of 100-200km. They would screen surrounded German units, who would then be reduced by hard-marching shock armies as the mobile groups conducted a mobile defence against German counter-attacks.\n\nThe most important aspect to remember is Maskirovka, all of these offensives were to be mounted in the utmost secrecy. Briefing were carried out in the third period (more on this later) Orally only, and just 5-10 days or so before the attack to front commanders, who in turn briefed the subordinates. The fact that entire tank armies (seriously, the Russians had formations called tank armies) were able to entrain, move 100s of miles, detrain and then launch these huge assault with only days of preparation and acting on verbal orders hints at an often underestimated genius in the west for Russian staffwork, professionalism and the effectiveness of maskirovka.\n\nFor the Russians, the great patriotic war is divided into three periods, based upon how effectively these principles were deployed- \n\nThe first from the 22 June 1941- 18th November 1942 saw an endless period of defeats as the germans advanced rapidly. They destroyed 28 divisions, and reduced an additional 70 to 50% strength. These defeats eventually led to the re-introduction of the operational method outlined above in PU-42. severe mistakes were continuously made. a lack of maskirovka meant attacks failed to achieve surprise, lack of concentration, poor command and a lack of appreciation of the operational level of warfare allowed opportunities to slip away.\n\nThe second period was a slow and painful learning experience, lasting from 19th November 1942 to the end of '43. every aspect of their warfighting capability was overhauled- command, control communications improved, better combat support and service support. Better weapons and more of them, overhauled formation organisation etc. they still made mistakes, but they slowly learnt from them and showed an increasing capacity for waging war. encirclements, where they occurred, took a considerable amount of time to reduce, but the effectiveness of such methods was obvious, and formations fought deeper, and reduced the encirclements far quicker.\n\nThe third period from 1944-45 is simply awesome. They were not just conducting these massive offensives one at a time anymore, these huge operations were now interlinked, as one closed down, another was just in the process of opening up. The perfect example of this is Operation Bagration. another would be the vistula-oder operation, 'liberating' most of Poland in 17 days. Additionally they constantly achieved complete surprise and destroyed tactically superior German armies at every turn. \n\nSo yeah, it didn't really matter that the Germans were tactically superior when the Russians had perfected their operational method for the operational level of war, were able to mass huge numbers of troops, achieving complete surprise and overwhelming the enemy through systematic manoeuvre warfare, crushing every single enemy formation they met with superior material, generalship and staffwork.\n\nReferences\n\nHastings, M., Armageddon, (London, Pan Books,2004)\n\nGlatz, D.M., Soviet Operational Art (London, Frank Cass, 1991)\n\nHarrison, R.W. The Russian Way of War (Laurence, University of Kansas press, 2001)\n\n (1) Dick, C.J. 'The operational employment of soviet armour in the great patriotic war' In Harris J.P. and Toase F.N. eds Armoured Warfare (London, Batsford Ltd.,1990)\n\n(2) Dick, C.J., 'Soviet Operation Art, Part 1' in International defence review, July 1988"
]
}
|
[] |
[] |
[
[],
[]
] |
|
15fv5d
|
Paper vs Electronics
|
Which is worse for your eyes, reading an actual book for extended periods or using an electronic device such as an Iphone or E-reader?
|
askscience
|
http://www.reddit.com/r/askscience/comments/15fv5d/paper_vs_electronics/
|
{
"a_id": [
"c7m3k3p"
],
"score": [
2
],
"text": [
"To add to that, how much difference is there between an e-ink e-reader and an actual book?"
]
}
|
[] |
[] |
[
[]
] |
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99cibf
|
How come Denmark ruled the Kalmar Union during 14-16 centuries, while Sweden was humongous in territory and Norway was considerably larger as well?
|
Why was Denmark the major power in the Union, being the smallest of the three? Considering the Union was signed in Kalmar, Sweden wouldn’t it make sense for Swedes to rule over the Union?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/99cibf/how_come_denmark_ruled_the_kalmar_union_during/
|
{
"a_id": [
"e4o0lpy"
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10
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"text": [
"Well, first let's sort out what the Kalmar Union _was_ (and wasn't). \n\nIt was a personal union, where three different countries had the same monarch. All three Scandinavian countries had elective monarchies at that time, albeit with a preference for electing people within he same dynasties. So the nobles (or _stormän_, or jarls if you want to go even farther back) could elect and also dethrone kings. That alone tells you that the monarch was not that strong. The countries did not have strong central government. Besides power being held by local jarls, the church and its bishops had huge power and wealth. The countries had also been hit hard by the Great Plague int he 14th century, and the Hanseatic League of north Germany was the dominant trading power in the Baltic. Ok, so the king is fairly weak. Being in another country there's not even a theoretical chance of exercising direct control anyway. \n\nSo in the late 15th century Danish Margarethe comes along, and in very simplified terms, basically inherits Denmark, marries into Norway and gets herself elected as queen of Sweden on the condition of defeating their German king, which she does. Not bad! Not having any heirs of her own, she adopts her sister's daughter's son ~~Bogislav~~ now Erik of Pomerania, has him coronated in Kalmar and then an act of union is signed or something. We don't really know! The document we have doesn't have the correct seals on it, is on paper rather than the expected parchment, has amendments and crossed-out stufff and doesn't exist in six copies like it says it should, so interpretations have varied. It may be just a draft document, or it might be an attested copy of a summary of what was decided, which is why the seals aren't right - they're for the witnesses and not the original signers.. Anyway, the content makes it clear that the three countries remain three countries, with their own laws. But they are also bound to to assist each other in war. \n\nSo in short the monarch gets to collect taxes, appoint foged/fogde/fogds as local administrators and tax collectors, appoint clergy (the Vatican at that particular point is too weak to stop it), handle foreign policy and wage war. The latter bit is an important to the motive of taking up competition with the Hanseatic League. (at least according to historian Erik Lönnroth)\n\nAnyway, Margarethe still continues as de facto ruler but with power being gradually transferred to Erik until her death (1412). Already 1410 Erik starts war for territory against Holstein (at the base of the Jutland peninsula) and then against he Hanseatic League, which, with breaks, would continue until the 1430s. In 1429 he also starts trying to claim the Sound Toll on all shipping in and out of the Baltic, which would ultimately become a Danish cash-cow all the way until the 19th century.\n\nThis isn't that much in the interest of Sweden and Norway though. Norway's selling fish to the Hansa, who have offices in Bergen. (Everyone's still Catholic, so fish on Fridays is a big deal, not to mention lent) and Sweden's shipping iron from Bergslagen down to Lübeck through Stockholm (nominally a Hanseatic city). They have much less to gain from picking a fight with the Hanseatics. Add to that, the Swedes are angry that Erik has been appointing Germans and Danes as _fogdar_ in the crown castles and estates, despite promises that only Swedish nobles would get those. Taxes are high as well.\n\nSupposedly the Danish _fogde_ of Västerås, Jens Erikssøn, was super-cruel and forced pregnant women to work so hard they had miscarriages and other horrible things, according to the Swedsh chronicle of Engelbrekt, which is a highly biased source nobody really takes too seriously. But in any case, the figure Engelbrekt comes out of Bergslagen in 1434 and demands Erikssøn be replaced, but gets nothing. So he raises an army and takes matters into his own hands, forces Erikssøn out of his castle and executes him after a trial. The rebellion continues, with Engelbrekt and his men successfully laying siege to castle after castle until he's taken 14 of them, 2 in the then-Danish province of Halland before a truce is declared. At which point only the 7 strongest castles are still left in Sweden (plus the ones in Finland). \n\nAnyway, in the peace negotiations they agree on only letting the king put foreigners in three castles, that he was required to listen to the advice of the national council (but not to follow it), and that there would be future discussions about taxes. Notably, Engelbrekt did not demand or appear to want to dissolve the union, but the secessionist tendencies nevertheless increased in Sweden. Engelbrekt passed away in 1436, and the Swedish nobles, considering Erik to have broken the treaty in a number of ways (including by intending to designate a relative as heir without any election) declared Erik deposed not long after that. The remainder of the history is a pretty messy back-and-forth of rules, but the short is that the Swedes pretty much do what they want while the Danish kings try to reclaim power, it breaks out into open hostilities under Sten Sture the Elder and then the Younger (no relation! the latter just took the former's name as a political statemnet). Initially these are however fought mostly between pro-and-anti-union Swedes rather than being the Sweden-vs-Denmark affair it became at the end.\n\nSten Sture the Younger is killed by the invading Danish king Kristian II, who takes Stockholm, has himself coronated as king of Sweden and then celebrates with the Stockholm Bloodbath, where about 100 anti-unionist Swedish nobles are executed. This leads to Gustav Vasa taking up the fight (bankrolled by the Hansa) and defeating the Danes, becoming king (1523) that's the formal end of the union. Vasa also converts the country to Lutheranism, confiscates church property and gathers power, and it's now you start to have a really strong central state both in Sweden and Denmark. Not long after Frederik I of Denmark decides that Danish nobles should have privileges in Norway as well, and it's now the union really starts transforming into the Kingdom of Denmark-Norway-where-Denmark-calls-all-the-shots. (However even as Sweden had started to pull away, Denmark-Norway signed a treaty in 1450 stating they'd have the same king 'in perpetuity', so one might also consider it to have started there)\n\nHo-kay, so that's the short version of the history of the Kalmar Union. As you can hopefully tell from the above, you can't really describe it as Denmark ruling the union, but rather a \"king in Denmark\" ruling the union. One with certain tendencies to put Denmark's interests first. \n\nHow could Sweden and Norway be dominated by Denmark despite being bigger? Well, first - territory doesn't matter, especially not when it's mostly empty, as was the case. Denmark was population-wise larger than Norway, and about the same as Sweden in 1400. More importantly though, Denmark _couldn't_ actually rule Sweden once Swedish opinion was firmly anti-Danish, as during the end of the Union. But up to the Stockholm Bloodbath there were a significant amount of pro-union Swedes, especially in the clergy. Roughly it started becoming more of a Sweden-vs-Denmark thing around 1500. Of course nationalist historiography in Sweden would long paint it all from the start as a grand war of liberation from a foreign oppressor rather than strife between pro- and anti-unionist Swedish factions. \n\nThe probable reason why the coronation and act of union (if there was one) was in Kalmar is because it was a conveniently-located coastal town, near the Swedish-Danish border (Blekinge province being Danish at the time), roughly equidistant from Copenhagen and Stockholm, with a royal palace and a cathedral. So a good spot for everyone except the Norwegians.\n\nFinally as for why Copenhagen would be the seat of power, there's the simple fact Margarete was Danish. Sweden was the country she had least personal connections with. Copenhagen was closer to the continent, which she had plenty of aristocratic connections with. It was closer to other useful things like the Universty of Rostock, where Danes usually studied at that time. (Copenhagen and Uppsala Universities were founded in the 1470s) It was also much closer to the rival Hanseatic league, without them having as much influence as they did in Stockholm (which still has a medieval church just for Germans in the old town, to this day). \n\nSources: Any good Scandinavian general-history book will tell you all or most of the above, but I don't really know what to recommend in English. I like Alf Henriksson's book in Swedish though. There are some nice Danish books about Margarete in particular too (even fictionalized novels about her life).\n\nI'm also taking the 'conventional' view and fallacy of viewing the union with the hindsight of its dissolution, in giving the period 1440-1520 short thrift. If you want to start getting more angles on the union history Gustafsson's ['A state that failed?'](_URL_0_) is a great place to start."
]
}
|
[] |
[] |
[
[
"http://dx.doi.org/10.1080/03468750600930720"
]
] |
|
ar49ob
|
how do we know what prehistoric life was like?
|
Watching through the Walking with Monsters: Life Before the Dinosaurs series... where do our theories of what life was like for those species come from?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ar49ob/eli5_how_do_we_know_what_prehistoric_life_was_like/
|
{
"a_id": [
"egkslbu"
],
"score": [
9
],
"text": [
"We have a good understanding of biomechanics, how the shape of bones, their growth and wear patterns, how ligaments were attached, and a lot of the details that tell us how the moved, how they ate and hunted. Teeth can tell you a lot about what sort of food an animal ate. The design of the head tells you how big their eyes, noses, and mouths were. Some bones have teeth marks, indicating that they were bitten by other dinosaurs. \n\nHere's a review article [_URL_0_](_URL_0_) on Dinosaur Biomechanics\n\n & #x200B;"
]
}
|
[] |
[] |
[
[
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634776/"
]
] |
|
53uetz
|
What was the fire rate of the matchlock musket, and how did it compare to wheel locks and flintlocks?
|
In my European history class, I was told that the matchlock took about two minutes to load, while a wheel lock only took about one. I don't know the firing rate of matchlocks or wheel locks, but I do know that Napoleonic infantry was expected to fire about 4-6 shots per minute with a flintlock. From about 12 seconds to two minutes seems like an extreme difference. Did it really take that long, or is it just an exaggeration?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/53uetz/what_was_the_fire_rate_of_the_matchlock_musket/
|
{
"a_id": [
"d7wlp92"
],
"score": [
7
],
"text": [
"16th century sources do indeed tend to be pretty unclear when it comes to firearm's rate of fire. Humfrey Barwick was a strong proponent of firearms at the end of the century and as such is probably represents the upper end of what might be expected in terms of fire rate. While serving as a mercenary for the French army he described a war meeting in which he overheard a nobleman claim that an arquebus could only be fired 10 times per hour. Some people apparently did think the fire rate was this low, but Barwick thought the man was daft and afterwards approached him offering to personally demonstrate shooting 40 times in one hour with a single piece. One shot every 1 minute and 30 seconds doesn't seem like much, but this seems to have only been the rate for long term fire over the course of an hour, which would have required occasionally cleaning the weapon, adjusting the match, and measuring the powder for each shot independently since a soldier at the time typically didn't carry 40 whole wooden cartridges at a time.\n\nFor short term rate of fire, later on in his discourse he described the maximum number of times that a soldier with a *musket* could shoot at an advancing army, which involved shooting once in the time it took the enemy to march (not running) 80 yards (presumably 60-90 seconds, he recommended making up the difference by shooting multiple bullets at a time as the enemy got closer). The fact that he says this is for a musket is significant because the 16th century musket was a very different beast compared to the muskets of the 17th and 18th centuries. It was extremely heavy with a longer barrel and a larger bore than later weapons and had to be supported by a forked rest while firing. Most troops at the time would have been armed with an arquebus or caliver, firearms which which were much lighter and had a much shorter barrel. Humfrey Barwick and Sir Roger Williams both wrote that the arquebus/caliver could fire twice as quickly as the clumsy musket could (though they prefered the latter because of its far greater force).\n\nThat would make the ideal rate of fire for the late 16th century arquebus/caliver: 30-45 seconds per shot max, 40 shots per hour sustained\n\nAnd for the heavy musket: 60-90 seconds per shot max, 20 shots per hour sustained.\n\nAs far as how rate of fire compares to the wheel lock or flintlock. A matchlock is generally more complicated to load since it requires constantly tending the match to keep it burning as well as adjusting the match length as it burns down. In addition manuals on loading reccomends removing the match after every shot and holding it in the opposite hand so the soldier doesn't accidentally blow himself up while handling powder (loading could still potentially be done much faster if shortcuts are taken as demonstrated by [this reenactor with an arquebus](_URL_0_)). A wheel lock firearm did away all this but added the need to reset the spring with a specialized tool after every shot. As far as flintlocks go, most manuals and sources tend to give a maximum fire rate of around 3, maybe four shots per minute. As far as I know, even with greatly simplified drills reenactors tend to have a lot of difficulty reloading a full sized Napoleonic musket in under 20 seconds.\n\nSo to sum up, 16th century muskets did take a long time to reload, largely due to its size. A flintlock musket was generally quicker and easier to reload than a 16th century matchlock caliver (which was similar in length and weight) though probably not as much as you're saying. And there was more to reload speed than the type of lock."
]
}
|
[] |
[] |
[
[
"https://www.youtube.com/watch?v=i-lGCtbg580"
]
] |
|
cxhe0k
|
what's a good source of hydration during a hurricane if water supply in stores is sold out?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/cxhe0k/eli5_whats_a_good_source_of_hydration_during_a/
|
{
"a_id": [
"eyl1kvi",
"eyl6rxn",
"eylj7ns"
],
"score": [
4,
3,
2
],
"text": [
"The point is to stock up beforehand. Water comes out of your faucet for hundreds of times cheaper than in the store.",
"Top part of the toilet. Seems gross but it’s actually clean except for a few airborne poo particles that sneak under the lid. No more than you breathe in all day anyway.",
"This is better in r/answers."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
1lvtc4
|
why does canceling a credit card with a zero balance hurt my credit score
|
I got an amazon card because it was supposed to allow me to buy a product on credit and avoid interest charges if I paid in full with in 6 months (20% APR thereafter!). They set my limit at $500 and I found something I wanted that costed about $600. My plan was to buy it and pay off $400 immediately and then $200 over the next 2 months. They denied my request to raise my limit, so I canceled the card (with out ever using it). My credit score dropped to below where it was before I got the card when I canceled it.
For the record, Amazon is not the only company that offers these kind of credit lines.
TL:DR - Why would canceling a new credit card with a zero balance hurt your overall credit score?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1lvtc4/eli5_why_does_canceling_a_credit_card_with_a_zero/
|
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"Assuming you have other credit and you have outstanding balances. Canceling increases your credit utilization %..\n\nLets say you have two cards and one has a balance\nA:$50/$100\nB: $0/$100\nYou are using 25% of your available credit.\n\nYou cancel card B\n\nYour are now using 50% of your available credit.\n\nCredit scores are a bit of a scam, they measure more your ability to keep paying than anything else... in fact most companies would prefer you keep paying your minimum and send them money for ever.\n\nThis is why the following can also hurt your score:\n- Having TOO Much available credit, IE you have lots of cards with $0 on them but the total credit has become a risk in-case you snap and max them all at once.\n- You have no credit cards, and have always payed for everything.. Even if you have good income, this can be a problem if they haven't been able to build a history of your reliability to pay.\n\nIf you have Netflix check if the movie [Maxed Out](_URL_0_) is still on their... it explains consumer debt fairly well.",
"Credit ratings are for the benefit of credit card companies, not for you. They want customers who can pay off their balance, but not so fast they don't earn interest off of it first.\n\nSome savvy customers try to get better rates by signing up for introductory rates cards, then cancelling them when the rate goes up. Credit card companies don't make money of these people, so credit ratings penalize this behavior."
]
}
|
[] |
[] |
[
[
"http://www.imdb.com/title/tt0762117/"
],
[]
] |
|
1w6l9w
|
Do computer screens have a direct effect on our levels of melatonin?
|
[This passage](_URL_0_) in the wikipedia states that melatonin is regulated by the amount of blue light, and in the same article, that melatonin helps to regulate sleep.
I'd hypothesize, and I've heard it mentioned, that computer monitors reduce melatonin levels in our bodies. However, I have an applet that tints the screen of my monitor yellow late at night, but I still find that it is difficult to fall asleep soon after looking at it.
So, is there something intrinsic about a computer monitor that effects our melatonin levels?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1w6l9w/do_computer_screens_have_a_direct_effect_on_our/
|
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"Source:\n_URL_0_\n\nBasically yes, but only very slightly. Computer screens do suppress Melatonin levels.",
"Here are a few papers I found that might help this discussion:\n\n \n1. Kubota T, Uchiyama M, Suzuki H, Shibui K, Kim K, et al. (2002). [\"Effects of nocturnal bright light on saliva melatonin, core body temperature and sleep propensity rhythms in human subjects.\"](_URL_0_)\n\n2. Cajochen C, Frey S, Anders D, Späti J, Bues M, et al. (2011). [\"Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance.\"](_URL_1_)\n\n---\n\n[The Research page on the f.lux website](_URL_2_) is rich with links to papers focused on this area of study.",
"The short answer is: yes, [computer monitors suppress the natural release of melatonin during the biological night](_URL_8_). But this is not unique to computer monitors -- *all* artificial and natural light that is bright enough suppresses melatonin, including blue and other colors of light.\n\nHere is how melatonin release normally works. The brain contains a master circadian clock -- it is a group of a few thousand neurons called the [suprachiasmatic nucleus (SCN)](_URL_6_) in the hypothalamus -- that keeps approximately 24-hour time. This clock sends signals to many other brain regions, one of which is the pineal gland. As an aside, the signal takes a [rather crazy pathway](_URL_7_) via the superior cervical ganglion in the neck. As a result, people who have severed their spinal cord above this level (i.e., people with tetraplegia) [release no detectable melatonin at all](_URL_0_).\n\nThe SCN signals the pineal gland to release melatonin across the night. The timing of melatonin release (in the total absence of light) is variable between individuals, but it is typical for melatonin release to begin a couple of hours before bed and to end around wake time. Light exposure during the night causes the SCN to send a stop signal to the pineal gland, causing melatonin release to cease. [Once the light source is removed, melatonin release will ramp up again if it is still during the nighttime release interval](_URL_4_). No melatonin is released during the biological day, even in darkness.\n\nSo how bright does the light need to be to suppress melatonin? It turns out the circadian system is very sensitive to light. Using broad-spectrum white light, [dim indoor lighting is sufficient to cause 50% suppression of melatonin release](_URL_10_).\n\nAnd what about the color of light? I often hear that it's just blue light that matters. This is not quite correct -- it's an oversimplification. The wikipedia passage you linked to is misleading in this respect. Let me explain why. The SCN receives light signals from a special population of cells in the retina, called [intrinsically-photosensitive retinal ganglion cells](_URL_5_), or ipRGCs for short. These cells are involved in sensing light for non-visual purposes, such as the circadian system and the pupillary reflex to light. It is possible to be visually blind yet still have this non-visual light-detecting system intact, but for some blind people this system is destroyed as well (e.g., if the eyes are removed), meaning the circadian rhythm is unable to be reset by light and runs at its intrinsic period (different between individuals and not exactly 24 hours).\n\nThe ipRGCs have their own photopigment called [melanopsin](_URL_3_) (which was only discovered in the last 20 years!), allowing them to detect light. The melanopsin molecule is most sensitive to blue light (around 460-480nm wavelength), which is where this idea that blue light is the only really important color of light for melatonin suppression comes from.\n\nHowever, things are a bit more complicated than that. The ipRGCs *also* receive inputs from the cone/rod system, which is maximally sensitive to green light! I have drawn a simple schematic of the pathways [here](_URL_9_). As a result, the suppression of melatonin is achieved by a combination of rod/cone and melanopsin responses to light. For relatively short light pulses (up to minutes), the rod/cone system is highly responsive and [green light is just as effective as blue light for suppressing melatonin](_URL_1_). For longer exposures (hours or longer), blue light has the greatest effect. However, if the light is bright enough, any color light can suppress melatonin release.\n\nThere are some programs now (e.g., f.lux) that redden the screen at night, thereby reducing the blue content of the light. While I am not aware of any rigorous studies of these programs to date, they are based on sound scientific reasoning. Reducing the blue content of light at night will reduce (but not eliminate) the effect on the circadian system. This makes it easier to fall asleep for two reasons. First, there will be less suppression of melatonin, and melatonin helps sleep onset to occur. Second, light in the late evening and early night causes [delay of the circadian rhythm](_URL_2_), which pushes the brain's sleep onset signal and the release of melatonin back later into the night, which can cause insomnia on that night and subsequent nights.",
"“Artificial light exposure between dusk and the time we go to bed at night suppresses release of the sleep-promoting hormone melatonin, enhances alertness and shifts circadian rhythms to a later hour–making it more difficult to fall asleep,” says Charles Czeisler, Ph.D., MD, Harvard Medical School and Brigham and Women’s Hospital. “This study reveals that light-emitting screens are in heavy use within the pivotal hour before sleep. Invasion of such alerting technologies into the bedroom may contribute to the high proportion of respondents who reported that they routinely get less sleep than they need.” Computer or laptop use is also common. Roughly six in ten (61%) say they use their laptops or computers at least a few nights a week within the hour before bed. More than half of generation Z’ers (55%) and slightly less of generation Y’ers (47%) say they surf the Internet every night or almost every night within the hour before sleep.\"\n\nNational Sleep Foundation, 2011 survey, via _URL_0_"
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Melatonin#Light_dependence"
] |
[
[
"http://www.ncbi.nlm.nih.gov/pubmed/21552190"
],
[
"http://www.ncbi.nlm.nih.gov/pubmed/11849730",
"http://www.ncbi.nlm.nih.gov/pubmed/21415172",
"http://justgetflux.com/research.html"
],
[
"http://press.endocrine.org/doi/abs/10.1210/jcem.85.6.6647",
"http://stm.sciencemag.org/content/2/31/31ra33.short",
"http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2003.040477/full",
"https://en.wikipedia.org/wiki/Melanopsin",
"http://onlinelibrary.wiley.com/doi/10.1111/j.1600-079X.1991.tb00003.x/abstract",
"https://en.wikipedia.org/wiki/Photosensitive_ganglion_cell",
"https://en.wikipedia.org/wiki/Suprachiasmatic_nucleus",
"http://www.fasebj.org/content/20/11/1874/F5.large.jpg",
"http://jap.physiology.org/content/110/5/1432.short",
"http://i.imgur.com/eqnY9DE.png",
"http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7793.2000.00695.x/full"
],
[
"http://www.gwern.net/Melatonin"
]
] |
|
22tnmq
|
why do indian reservations have such high unemployment?
|
So the common perception of modern Indian Reservations is low income, high unemployment, high crime rates, low standard of living, except in the case of casinos. I guess the first question is, is this actually true, and if so why?
I understand there are probably complex ideas here, but there are probably some simple underlying factors.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/22tnmq/eli5why_do_indian_reservations_have_such_high/
|
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"Very true and in case you have forgotten, the reservations were the tracts of mostly worthless land nobody wanted, far from civilisation. That should explain the dismal prospects ofvthe denizens.",
"First Reason: No jobs... \nSecond Reason: Remote... \nThird Reason: Culture Shock...\n\nSimplest terms these three in combination with each other is why... Every other problem stems from these...",
"Yes. They're in bad locations in the middle of nowhere. What sort of jobs would be found there? They're usually too poor to leave, and if they do, they generally won't be supported by the other members for betraying their culture. And if they leave, they really will eventually lose it. I guess this sort of things applies to poor inner city youth too, or most groups in poverty who band together."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
asxdxy
|
how do motor boat engines not get water logged?
|
Any time that there's moving parts, especially in a circular motion, wouldn't the water find a way in? Or are the moving parts so disconnected from the engine that it just doesn't reach it?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/asxdxy/eli5_how_do_motor_boat_engines_not_get_water/
|
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"Same reason your car motor doesn't get water logged when you drive in rain or puddles.\n\nThe motor is not in the water. It's spins a shaft which is also attached to a propeller, that goes into the water. ",
"The actual motor is well above the waterline, usually at least 1-2 feet. Like on this outboard boat for example \n\n_URL_0_\n\nThe actual motor part is in that black plastic housing, there's possibly a gear box and shaft that goes down to the actual propeller. In theory water could get into the housing for the shaft, proper maintenance of the shaft seals, and a lot of marine rated grease will protect them from water damage. The grease lubricates any moving parts, but also fills any gaps with grease where water could enter. ",
"On large sailboats with internal motors there is a thing called a stuffing box. Between the water and the engine is a box like compartment that contains a grease infused material that keeps water out yet is slippery enough to allow the shaft to spin. The compartment on my boat is six or eight inches deep, and it is stuffed tightly so there is basically no room for water to enter. One interesting aspect of this is that if there isn't a tiny bit of water coming through, like a drip a minute, the grease can dry out. So the box is made so it can be tightened or loosened. Eventually you run out of room to tighten and you have to pull the boat out of the water and replace the material. "
]
}
|
[] |
[] |
[
[],
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"https://www.powerandmotoryacht.com/.image/t_share/MTUwMTAzMDIyMTA1OTk1MDM0/brackets-on-a-stamas-center-console-.jpg"
],
[]
] |
|
8b3pec
|
Are there any good book (for layman) about climate changes and their impact on the course of human history/prehistory? Hopefully with maps.
|
Climate changes are often mentioned in history books as impacting human societies around the world. E.g., Little Ice Age, some desert not being a desert during this period, some region dried up during this period prompting immigration, etc.
So I thought having a comprehensive book on the topic should be nice. I am particularly interested in Europe, North Africa, Middle East, Central Asia and China. Hopefully with maps showing the climate change region-by-region. Online sources too would be great.
Thanks in advance!
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8b3pec/are_there_any_good_book_for_layman_about_climate/
|
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"Although comprehensive only in the sense that it attempts to cover the whole globe across most of the seventeenth century, with special focus on the impact of the Little Ice Age and associated abnormal El Nino episodes, Geoffrey Parker's book *The Global Crisis* (2013) is a major contribution by a senior historian to efforts to integrate social, political and environmental history. \n\nParker's thesis is that climate change during this period is crucial to understanding the very widespread political turmoil of the 17th century, which \"saw more cases of simultaneous state breakdown around the globe than any previous or subsequent age\" – from the Thirty Years War and British civil wars to the Fronde, the downfall of the Ming dynasty, civil war in Mughal India, the overthrow of the African kingdom of Kongo, and the disintegration of the Polish-Lithuanian commonwealth. \n\nParker contends that the period was also marked by a sharp increase in the number of revolts, and more and longer wars than occurred in any comparable period before the 20th century, all accompanied by dearth and plague leading to massive mortality – which in turn led (as Hobbes suggested in *Leviathan*) to the feeling that\n\n > \"There is [now] no place for industry, because the fruit thereof is uncertain, and consequently no culture of the earth; no navigation, nor use of the commodities that may be imported by sea; no commodious building; ... no arts; no letters; no society. And, which is worst of all, continual fear and danger of violent death; and the life of man, solitary, poor, nasty, brutish, and short.\"\n\nand which prompted the contemporary Welsh historian James Howell to conclude that:\n\n > \"God Almighty has a quarrel lately with all mankind, and given the reins to the ill spirit to compass the whole earth; for within these twelve years [1637-49] there have the strangest revolutions and horridest things happened, not only in Europe but all the world over, that have befallen mankind, I dare boldly say, since Adam fell, in so short a revolution of time ... [Such] monstrous things have happened [that] it seems the whole world is off the hinges.\"\n\nFinally, although perhaps least persuasively, Parker also attempts to explain why Japan, pretty much alone among the major nations studied, escaped most of the problems caused by climate change in this period.\n\nIt's a very big book, but he writes extremely well and it flies by, if the subject matter itself grips you."
]
}
|
[] |
[] |
[
[]
] |
|
4gq882
|
reverse entropy
|
Could it ever be possible? Why or why not?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4gq882/elif_reverse_entropy/
|
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"imagine you have a jar of marbles that you tip over. The marbles all go out in different directions, ricochet off of eachother, and settle. Now, you must put them back how they were before. How? That's impossible, that's so much data to somehow learn, which way each marble went and what it hit and how at what angle and so on to reach it's final resting spot.\n\nimagine if you could look through time, though. You'd see the path that every single marble took and the way they scattered would look very apparent to you, like a tree with branches. You could easily tell how they got there and how to reverse it. \n\nReverse entropy is only possible by timetravel, but we cannot do that. As time advances, the past is braided, so to speak, into one singular universe, the universe we at this very moment are at the head of. In the future there's infinite possibilities but as we travel through the fourth dimension, we collapse/destroy all those universes into the one we right now are witnessing. The past is beyond our reach, and the future doesn't exist yet, or rather it exists in every infinite way. So we're kinda stuck in the present, just like how a 3D apple passing through a 2D world would only exist to the 2D world as that slice of 2D it is at that current time, we're that apple, and time is what we're passing through, and we can only experience the world as it is at this very moment we are advancing through it. And as such, it's not possible for us to go back and look how the marbles fell and scattered... But the secret to reversing entropy might hold the way to look back in time, and vice versa. Just like in that 2D world they have no concept of ALL of the apple in one physical 3D existence, only slices of it. They might have the cognition to imagine a 3D apple, just like how we humans have memory and forethought of the past and future, but it's really just a makeshift bandaid solution. \n\nIt's all very theoretical stuff."
]
}
|
[] |
[] |
[
[]
] |
|
6zgvsl
|
how do companies like walmart profit from selling gift cards to other services when a gift card costs the amount of credit it's worth?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6zgvsl/eli5_how_do_companies_like_walmart_profit_from/
|
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"it is a strategy used to get people in the door, much like a sale, it is ok to not make as much money on one or two items because usually when people come in they buy more than they were intending to in the first place, it happens. so to get people in the door it is actually more profitable to sell some things at a reduced price or even at a loss if it means you are making more profit on other goods and or services",
"Interesting. I always just assumed that they worked out a deal with those companies. Say Starbucks will sell Walmart a $25 card at the cost of $20. Now Walmart is +$5 and Starbucks is still getting at least most of their profit margin. ",
"Lost and not redeemed cards ale happen a lot. A radio ad runs in my area that offers to mKE gift cards for businesses and they talk about only 85% or something get redeemed",
"Walmart buys the cards for less than their face value. They make money on the difference. \n\nThe exception is Visa/MC gift cards, which are actually sold at a premium (spend $35 for a $25 MC gift card, for example.) In that case Walmart gets part of the premium.",
"Generally speaking, the merchant selling the gift card gets a small commission on the sale.\n\nExample: Target sells a $100 Red Lobster gift card. Target activates the card and collects a $5 commission, the other $95 goes to Red Lobster. The customer goes out to eat, gets the check for $100 and pays using the gift card.\n\nIn reality it's a bit more complicated.",
"I always assumed that they made a lot of money from lost gift cards and when there was such a minuscule amount left on one that it just gets thrown away.",
"They dont make or lose anything from gift cards other then labor cost to put them on shelves..Its to generated foot traffic. If you come in to buy it some times while you wait in line you will buy say a drink or a candy bar and thats profit. Also not everyone uses all the money on a gift card. \n\n For example you might get a $25 gift card and you spend $24 of it. Now you have $1 left and there is nothing that is worth $1. So now you have to decide either A. throw away the gift card and lose out on $1 meaning the company gains a $1 profit or B. You spend say $5 and to use that $1 and end up spending $4 out of pocket meaning the company profits from you spending more money beyond the gift card",
"Retail stores *really* like when customer have their gift cards. When someone buys a target gift card, it's basically* guaranteed sales for them. By selling gift cards in other stores, they extend their reach, and make sales to customers who might not have otherwise stepped foot or thought about target in the first place.\n\nIn return for this extra sales opportunity, they're willing to share back a little bit of that sale to whatever company is selling the card for them. Really popular gift cards like Apple will pay out 1% of the card value. Less popular cards like regional restaurant will pay out a higher amount, usually up to 5%, to entire other businesses into carrying their cards. Since most stores make much more then 5% on each sale, it's worth it to them to give a \"cut\" to some other store to sell their gift card - they'll still make a profit when the card is redeemed.\n\nBut even this amount would usually not be enough to get a store to sell your product. A regular grocery store will make between 15% and 30% on every item they sell, so a 5% gift card is not very profitable. To offset this, gift card malls (the industry term for selling other store gift cards in your store) have a few other advantages.\n\n1. They're low risk. The merchant doesn't have to buy the cards - they're given to them for free. The cards don't have any value until activated, so theft is not a problem for the store selling them. Compare that to regular products, which they have to pay for up front, and if they're stolen the store is out the cost of the item. Gift cards also don't affect their on hand inventory value, which means they don't drive up insurance costs.\n\n2. They don't take up shelf space. Shelf space in a store is a valuable commodity - most products need to be on a shelf, and the more space you have, the more stuff you can sell. Compare a small independent convenience store to a Walmart - the reason the convenience store is crammed full of stuff is because they are trying to maximize the limited space they have. Gift card malls can be hung on a wall, put on a spinner and shoved in a corner, or left in front of a register. Most stores can find a space where the cards are essentially taking up 0 space that could have been filled with more profitable products. \n\n3. They draw in more customers. Even if 90% of the shoppers who buy a gift card don't buy anything else, the 10% who realize they need milk and grab a gallon from the back are \"free\" extra sales the store might not have gotten anyway. \n\n**Source** - I used to work for a company that pushed gift card malls as a value added option with our POS platform, to independent grocery stores.\n\n\\* Some people are saying stores love them because they keep the money from un-redeemed gift cards. This isn't quite accurate. In the US, gift cards cant expire for at least five years. Some states don't let them [expire ever](_URL_0_). Businesses are required to hold the money they get from selling the gift cards in a separate holding account while waiting for the cards to be redeemed, at which point they can pull the cash into their usual revenue. The exception is when a business shuts down, then they can take any outstanding gift card balances as cash. Most companies would rather have the gift card redeemed quick so they can realize the revenue now, rather then wait five years, even if the payoff could be bigger. Revenue means growth, cash sitting in an account they can't access means accounting costs. (Edited for accuracy)",
"The gift card companies pay a commission to the stockist. They can afford to do this as something like 30% of all gift cards are not redeemed within their validity period. And the provider of the card (iTunes, whatever), has a profit margin on their goods. $50 of music downloads doesn't cost $50 to Apple. So the combination of unredeemed value and margin for profit more than covers the commission the retailer receives.",
"Because the face value of the gift card is only the consumer cost not the actually profit margin of the item. Along the supply chain of an item are multiple profit margins ",
"They get a cut obviously. Most of those gift card racks are from one vendor who's the middleman. They literally buy that space in the store. Maybe it's a percentage of sales but likely it's a fixed price. X vendor pays Y retailer a set price to have 2 kiosks in every location for a year. The vendor come regularly and fills the racks and makes sure nothing is spoiling the sight lines etc that they pay for. Coke pays for shelf space in a grocery store and so does Pepsi, Tide, etc. ",
"You likely won't use the whole amount. If you have a 50 dollar card maybe you spend 46 and forget to use the rest. Assume most people do it they get pure profit. Some people just never use them or lose it. That's cash to the company bottom line",
"In addition to what other folks are saying about guaranteed sales (i.e. you have a gift card to Le Shoppe Manifique, you're going to use it there), there's also the significant portion of them that\n#never gets used\n\nIf 5% of them never get used, then you, as Le Shoppe Manifique's owner, just realized a 5% price increase on everything sold via gift cards. Free money!"
]
}
|
[] |
[] |
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[],
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[],
[],
[],
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[],
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"http://consumersunion.org/research/state-gift-card-consumer-protection-laws-2013-update/"
],
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] |
||
1fktav
|
Why are owls associated with intelligence?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1fktav/why_are_owls_associated_with_intelligence/
|
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"To answer the former question: Athena was the protector of Athens. Athena had an owl because owls were abundant in Athens. There's a proverb that says \"bring owls to Athens\" for a pointless venture.\n\n\nedit: I was answering the question of why owls are associated with the Greek goddess Athena.",
"Owls have long been considered deeply connected with magic and shamanism (even such as in our tales of Arthur, Harry Potter, etc) and that, coupled with the ability that they can see at night and their eyes are in a fixed position makes them seem like they are more intuitive and intelligent, seeing (otherworldy) things that humans cannot. Owls also share similar personality traits with cats, another animal long regarded for it's intellect and cunning. \n\nEdit: Since there seem to be quite a few downvotes-without-retort, here are just a couple of easily google-able pages that will show the same claims.\n\n_URL_1_\n\n_URL_0_\n",
"The question is somewhat biased - owls are not associated with wisdom in much of the world. In Africa, for example, they are harbingers of evil and associated with black magic.",
"The Owls of Athena [Wikipedia article](_URL_0_) has an interesting alternate theory about their vision:\n\n > On the other hand, Cynthia Berger theorize about the appeal of some characteristics of owls —such as their ability to see in the dark— to be used as symbol of wisdom (Berger, Cynthia (2005). [Owls](_URL_1_). Mechanicsburg, PA, USA: Stackpole Books. p. X. ISBN 9780811732130.)\n\n",
"Owls are not always considered intelligent; you need to factor in culture as well. The Hindi word for owl which sounds something like ['oolu'](_URL_0_) actually means foolish. "
]
}
|
[] |
[] |
[
[],
[
"http://www.britannica.com/EBchecked/topic/436310/owl",
"http://www.macrameowl.com/owl_symbolism.html"
],
[],
[
"http://en.wikipedia.org/wiki/Owl_of_Athena#Greece",
"http://books.google.com.mx/books?id=azCFGSeKjw4C&lpg=PR10&dq=Minerva%27s%20owl%20wisdom&pg=PR10#v=onepage&q&f=false"
],
[
"http://blogs.telegraph.co.uk/news/peterfoster/3628081/A_wise_owl_or_a_foolish_oolu/"
]
] |
||
42j6i5
|
sound effects
|
How do people get the sound effects that can be used in music or movies? Like for an AK47 shootinh do they actually get a mic and just record it, it's hard for me to see them doing that for things like tires screeching or a punch.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/42j6i5/eli5_sound_effects/
|
{
"a_id": [
"czarpan",
"czau3bi"
],
"score": [
2,
2
],
"text": [
"Yes, sometimes they just go out to a shooting range or go out driving with a bunch of sound equipment.\n\nUsually for movies they just buy the sound effects from someone who already did that and is selling all the sound effects.\n\nEither way, studios end up with libraries of sound effects they use.",
"Depending on the budget of the movie (nowadays, it has to be a pretty high budget -- think Transformers, etc), they can record sound effects special for the actual film. This is done during the post production process and overseen usually by an experienced sound supervisor. \n\nHere's an excerpt from Academy Award winning sound designer Dane Davis as he was describing recording sounds for the chase scene in the second Matrix movie: \n\n > \"We had to drop the cars right in the middle of the microphone array, and then keep them from rolling over the mics or over all of us. We also had a couple of wrecking balls — including one that weighed 3,500 pounds — that we dropped through the cars. At one point, one of the balls went all the way through the cars, through the concrete under them, into the dirt and back up through the car, then rolled over a bunch of mic cables and came to rest on a PZM mic, completely crushing it. We got some really great sounds out of that.” [link](_URL_0_)\n\nThese big-production sound effects are often mixed with \"Foley\" recorded in a studio, things like the sound of punching has been made with smashing celery, etc. \n\nFor lower budget films and TV, they will often use small amount of foley recorded in studio if it's a very unique scene or sound. \n\nThere's often \"sound design\" aspects to creating the entire collection of sounds for a film, such as recording something in the wild and then processing it afterwards using digital or analog effects to create the sound needed. I read somewhere that one of the sound designers on the original Star Wars created the lightsaber effect by hitting a wrench against one of those thick guylines that secure a powerline pole (couldn't find a reference for this, I'm sure someone will clarify if I'm wrong). \n\nSound designers and supervisors will have hard drives full of hundreds of thousands (if not millions) of these sounds that they carry around with them, and they will often share them with their peers. Probably the majority of sound effects these days that you will hear, if it's the occasional gunshot or punch or car crash, have been used at least dozens of times before and may have been recorded 10-20 years ago and reused endlessly. \n\n*TL;DR* Yes, they record sound FX by actually recording real guns, cars, etc, but depending on budget they may reuse sounds they already have. "
]
}
|
[] |
[] |
[
[],
[
"http://www.mixonline.com/news/films-tv/matrix-reloaded/369031"
]
] |
|
195zt7
|
How important are cyanobacteria to *keeping* the earth's atmosphere oxygenated?
|
I've just been reading about the oxygenation revolution and the 3.5 billion year old fossils of cyanobacteria that may have largely driven that revolution.
But I was wondering if, since oxygen will react with almost anything, and it is difficult to keep it free, if the same cyanobacteria that are alive today play a significant role in *keeping* the oxygen in the air.
Is this a possibility?
|
askscience
|
http://www.reddit.com/r/askscience/comments/195zt7/how_important_are_cyanobacteria_to_keeping_the/
|
{
"a_id": [
"c8lfr0x"
],
"score": [
2
],
"text": [
"Indeed, they are very important. [Here](_URL_0_) is a Nat. Geo. article on this very topic (though they are talking about all phytoplankton, but just cyanobacteria). It's a bit old (2004), but still agrees with several other more recent sources I found. The short answer is that, yes, photosynthetic unicellular marine microorganisms (cyanobacteria being one of the most abundant) are very important for maintaining our atmospheric oxygen."
]
}
|
[] |
[] |
[
[
"http://news.nationalgeographic.com/news/2004/06/0607_040607_phytoplankton.html"
]
] |
|
1wpgez
|
is it true that if you eat human flesh your body will uncontrollably shake? if so, why?
|
Curious. Just finished the Book of Eli.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1wpgez/eli5_is_it_true_that_if_you_eat_human_flesh_your/
|
{
"a_id": [
"cf46uzp",
"cf46wvz"
],
"score": [
3,
2
],
"text": [
"It could happen, yes. It's due to a prion disease called Kuru: _URL_0_",
"Not quite.\n\nTremors from cannabalism is a result of 'Transmissible spongiform encephalopathy', and it results from eating brain tissue that contain certain prions (a kind of defective protein that can act like an infectious agent). Its akin to Mad Cow Disease, which is caused by cows eating infected brain tissue from sheep remains that had been added to the cow feed for added protein."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Kuru_%28disease%29"
],
[]
] |
|
3rk4cs
|
how is the sugar coating on sour candy so much different than table sugar?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3rk4cs/eli5_how_is_the_sugar_coating_on_sour_candy_so/
|
{
"a_id": [
"cworif0"
],
"score": [
3
],
"text": [
"From Wikipedia: *Sour sanding, or sour sugar, is a food ingredient that is used to impart a sour flavor, made from citric or tartaric acid and sugar. It is used to coat sour candies like Sour Patch Kids or to make hard candies tart, such as acid drops or SweeTarts.* It's not quite the same thing. "
]
}
|
[] |
[] |
[
[]
] |
|
1ivxvy
|
how are airplanes able to travel through the air despite being heavier than air? also, what exactly is jet propulsion?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1ivxvy/eli5_how_are_airplanes_able_to_travel_through_the/
|
{
"a_id": [
"cb8jw0x"
],
"score": [
3
],
"text": [
"Airplanes fly by generating lift. Their wings are shaped in such a way that when they are moving through the air, the air passing over the top of the wing is moving faster than the air moving under the wing. The faster that air moves, the lower pressure it has. Since the faster moving air on top of the wing has less pressure than the slower moving air on the bottom of the wing it generates lift and causes the plane to rise. \n\nJet engines work by taking in a large amount of air and compressing it into a small space. Fuel is then added to the compressed air and it is ignited, or basically blown up. The more air that can be pushed in and the more it can be compressed, the more powerful the explosion will be. The force of the explosion pushes out of the back of the jet engine causing forward thrust. In reality it creates more pressure pushing forward on the jet engine than at the rear of the jet engine, the thrust isn't actually pushing off of anything behind it. That's why boosters still work in space where there is no air."
]
}
|
[] |
[] |
[
[]
] |
||
483ggs
|
when you forget something, why does retracing your steps often make you remember? (such as going back to a webpage you closed or redoing the activity you were doing)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/483ggs/eli5_when_you_forget_something_why_does_retracing/
|
{
"a_id": [
"d0gzshe"
],
"score": [
2
],
"text": [
"For me, it tends to be that something in what I was doing was the impetus for the thought to begin with. When that stimulus occurs again, the thought happens again in the same way it did initially."
]
}
|
[] |
[] |
[
[]
] |
||
a8a86r
|
Is radioactive decay temperature-dependent?
|
Does the rate of radioactive decay for an isotope vary with temperature? For example uranium-235 has a half-life of 703.8 million years, but would cooling to absolute zero (or very close to absolute zero) have a significant influence of the rate of decay?
|
askscience
|
https://www.reddit.com/r/askscience/comments/a8a86r/is_radioactive_decay_temperaturedependent/
|
{
"a_id": [
"ec91bix"
],
"score": [
27
],
"text": [
"Typically is not, the nucleus is so much smaller than the atom that it doesn't \"care\" what's happening around it (imagine a marble at the center of one of those giant human hamster balls). There are maybe a few small exceptions. \n\nOne could argue that the electron-capture mechanism (sometimes called inverse beta decay) depends on the probability of the electron being found in the nucleus, which depends on the lattice arrangement which depends on temperature. The difficulty with testing this is that the functioning of particle detectors for measuring decay also depends on temperature. There were a few studies purporting to find temperature dependence, [but a more precise study](_URL_0_) did not.\n\nThere's also the phenomenon that a superheated gas might have atoms that experience time dilation and appear to have slower decay rate. It's not feasible to make a gas that hot with current technology, but slower decay rates of nuclei have been observed in a particle accelerator."
]
}
|
[] |
[] |
[
[
"https://arxiv.org/pdf/0910.4338.pdf"
]
] |
|
1w89u3
|
batteries: rechargeable vs disposable
|
What is the difference between the two forms of batteries? Why aren't all batteries rechargeable? wouldn't that be a lot more efficient?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1w89u3/batteries_rechargeable_vs_disposable/
|
{
"a_id": [
"cezrbbz"
],
"score": [
5
],
"text": [
"Rechargable batteries have different chemistry from disposable batteries. And the different chemistries result in various pros and cons.\n\nA NiMH AA has a voltage of 1.2, but an alkaline AA is 1.5. But most electronics tolerate these small differences.\n\n\nA more significant difference for a user would be the problem of auto-discharge. Rechargeable cells like a NiMH, even when not plugged in, lose charge with time.\n\nSo while your remotes, mouse, and game controllers can utilize recharging cells, you should NOT use rechargables for something like an emergency-kit's flashlight which you store away for hurricane season, because chances are you won't be charging them periodically waiting for the unexpected to happen.\n\nSo there are legitimate reasons to use alkalines, but their use obviously is too common to be explained by those circumstances. My guess is selling disposable batteries is more profitable for them, or that people are too lazy, or both."
]
}
|
[] |
[] |
[
[]
] |
|
2kortk
|
why was microsoft criticised for bundling a browser and media player with their os, but is apple allowed to bundle a computer with their os?
|
I know the examples are a bit different, but in the end it does constitute product tying, right?
Please, no flaming or brand wars. I'm just curious what the difference is.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2kortk/eli5_why_was_microsoft_criticised_for_bundling_a/
|
{
"a_id": [
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"clnbfqc",
"clnctl2",
"clncwn9",
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8,
2,
6,
6,
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"text": [
"Microsoft was leveraging its monopoly to put a much smaller rival out of business.",
"The difference is that Windows is very widely used for more than normal computing, servers and other uses are common. Not to mention that you can install windows on basically anything where as OSX can only be installed on MACs (easily) \n\nPeople aren't as upset when a mac comes with extra software like that since thats what they bought it for but many pc users bought windows to use as a barebones OS instead of a \"normal\" computer. ",
"Honestly, it is because lawyers and judges are idiots.\n\nWhen the the browser bundling issue came up in the Microsoft anti-trust case in 2001, the legal system was clueless when it came to technology. From a technical perspective, the charges against Microsoft were nonsensical, and Microsoft's defense was equally incoherent.\n\nThere were no good guys or bad guys here, just a bunch of idiots, and no valid conclusions can be drawn from that case.\n\n ",
"You've gotten a few answers but I don't think they tell the whole story.\n\nYou have to remember this was a while ago now and the market was a bit different. There was a time when people paid money for web browsers. You literally went to a physical store and bought Netscape Navigator. So Netscape was charging for its browser and the MS, who dominated the computer market, started offering Internet Explorer for free.\n\nMS was leveraging their monopoly on the PC to but IE in front of everyone's face, so why would anyone pay for Netscape? Even after Netscape moved to a free model IE was the default browser on the default operating system and if you were not tech savvy you probably didn't even know Netscape existed.\n\nApple is not in a dominate market position therefore they cannot abuse a monopoly situation.",
"Nobody cares about \"anti-competitive\" practices by a small player. There has never been much of a risk of Apple becomming a monopoly the way there was with MSFT. It's all about market share. Everyone is going to go after the one on top.",
"Legally, tying arrangements are only a problem if they involve tying a product that dominates its market to another product that doesn't in an effort to stifle competition in the market for the second product. Apple does not dominate either computer or OS market, so tying one to the other isn't legally a problem. In the Microsoft cases, Microsoft dominated the operating system market and by tying its browser to its operating system it was (theoretically) extending that dominance into the market for browsers."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[]
] |
|
20aw9h
|
why do some nutrition labels read "total carbohydrates 30g" but sugars will say "sugars 22g"?
|
without any mention of fiber? what/where is the unaccounted 8g of carbs?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/20aw9h/eli5_why_do_some_nutrition_labels_read_total/
|
{
"a_id": [
"cg1g3vr"
],
"score": [
3
],
"text": [
"Sugars are a simple type of carbohydrate. \n\nFibre (cellulose) is technically a carbohydrate, but it is not digestible and has no direct nutritional value. It is therefore not included in the total carbohydrates of food."
]
}
|
[] |
[] |
[
[]
] |
|
fuevro
|
what do the schrödinger and dirac equations describe and what's the difference?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/fuevro/eli5_what_do_the_schrödinger_and_dirac_equations/
|
{
"a_id": [
"fme2yi3"
],
"score": [
2
],
"text": [
"The Schrödinger equation (ih d/dt psi = H psi) is a very general statement about quantum mechanics: the phase of a state changes (it ”turns”, in a way) proportional to its energy. It can describe many different things as long as you use the correct H. Note that I’m NOT talking about the common formulation ih d/dt psi = -h^2 / 2m psi + V psi, which is the specific case for a singe nonrelativistic (slow) particle. The Dirac equation is another specific instance of it, describing relativistic (very fast) spin-1/2 particles (like electrons) and has spin and antiparticles built into it."
]
}
|
[] |
[] |
[
[]
] |
||
8hiidl
|
English (Latin?) certainly made its view of left-handed people clear (sinister - left handed) but are there any cultures were left-handedness is seen as better than right-handedness?
|
I couldn’t find a more appropriate subreddit and I’ve debated posting it for some half hour now, hope it fits the sub because I’m really curious about this.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8hiidl/english_latin_certainly_made_its_view_of/
|
{
"a_id": [
"dyk3lql"
],
"score": [
4
],
"text": [
"You might try /r/Askanthropology. There may be someone here with the answer, but this other sub has a concentration of people with a background in comparative ethnography."
]
}
|
[] |
[] |
[
[]
] |
|
kaocu
|
obama's new jobs bill.
|
With a very conservative family I know I'm going to hear nothing but complaining about it in the coming weeks regardless of whether it's good or bad, I'd like to know the real truth.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/kaocu/eli5_obamas_new_jobs_bill/
|
{
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],
"text": [
"good one! I can't wait for an answer.",
"You can read about it [Right Here](_URL_0_) from a previous ELI5. Cheers.",
"good one! I can't wait for an answer.",
"You can read about it [Right Here](_URL_0_) from a previous ELI5. Cheers."
]
}
|
[] |
[] |
[
[],
[
"http://www.reddit.com/r/explainlikeimfive/comments/k9ggy/eli5_obamas_new_job_plan/"
],
[],
[
"http://www.reddit.com/r/explainlikeimfive/comments/k9ggy/eli5_obamas_new_job_plan/"
]
] |
|
356fh1
|
what makes the noise in an engine?
|
Vroom vroom 🚘🚘
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/356fh1/eli5_what_makes_the_noise_in_an_engine/
|
{
"a_id": [
"cr1ehvu",
"cr1h0f8"
],
"score": [
5,
4
],
"text": [
"Its either the engine lifter's noise, valve noise, the combustion, bearing noise, or the exhaust of the car itself you're talking about at the moment.\n\n\nVroom vroom.",
"A short answer: the explosions cause by the sparks within the pistons (or cylinders) cause the sound. Vroom Vroom, if you will."
]
}
|
[] |
[] |
[
[],
[]
] |
|
26z988
|
what is al qaeda fighting for?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/26z988/eli5_what_is_al_qaeda_fighting_for/
|
{
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"text": [
"Islamic caliphate - A worldwide dominance of Islam and governance according to sharia.",
"[Here is a letter from Osama Bin Laden to America](_URL_0_) The basis of this is that we are supporting acts of aggression against Muslims via Israel, occupying their Holy Land, and we are not Muslims.",
"Its not a simple answer because Al Qaeda is NOT a simple terrorist group.\n\nThe point of Al Qaeda, as laid out by Bin Laden, is not a single group with a single goal, but as the Arabic translation plainly tell us, to be \"the base\" for multiple related but not 100% similar groups, causes, and goals. \n\nThis is NO single thing Al Qaeda wants because the is NO single Al Qaeda. There's Al Qaeda in Iraq (now fracturing into AQI and ISIS), there's Al Qaeda in the Maghreb (AQM), Al Qaeda in the Arab Peninsula, also Al Qaeda in the Horn of Africa. The original Afghanistan franchise is also still present with the remnants of the Taliban in the Pakistan Tribal areas. Plus these franchises, literally they are franchises, they use the Al Qaeda name and sometimes share finances/fighters but they have semi-independent leadership and act towards separate goals. \n\nBin Laden states goals where many, but the usual demands in his fatwa videos included: Removal of US soldiers and sailors from Saudi Arabia, end of US support of Israel, the overthrow of several western friendly Middle East governments, and the replacement of them with a unified Islamic Caliphate or one super Arab-Muslim state in the gulf. \n\nOthers linked to Al Qaeda have also demanded the forced conversion of all non-Muslims, the replacement of civil law with Sharia religious law, the complete destruction of Israel, or for an Islamic Caliphate to extend beyond the middle east and conquer the world. \n\nTo accomplish these, Al Qaeda was supposed to be a linked network of terrorism support groups. The training camps in pre 9/11 Afghanistan hosted terrorists from all over the world. Al Qaeda would link financier X with group Y to move money. They would provide their franchise groups with better planning of attacks and strategy. You could share bomb makers. One guy learns an IED to defeat armored Humvees, Al Qaeda would hook up other groups with him. It was envisioned as a one stop terrorist super store/support line. \n\nEach individual group had its own motivations, usually less about Islam and infidels, and more about seizing regional power and taking political control. Al Qaeda in Iraq talks a good game about hating Jews and Americans, but really they just bomb and kill other Iraqi Muslims so that AQI can get more political control over the west of Iraq. They couldn't care less about Al Qaeda in the Maghreb fighting in Libya or Algeria or the Taliban's fight in Afghanistan. Bin Laden simply built them a common support network for training, money, and strategy; but not a governing body where they vote on the general platforms of terrorism. \n\nThis split has only gotten bigger since most of the senior leadership have been killed or captured since 9/11. Al Qaeda is less about the spectacular overseas attacks (9/11, London bombings, Madrid train attacks) of which OBL and KSM were proponents and more about these regional franchises attacking regionally for regional gain. \n \n**TL:DR** What exactly Al Qaeda wants depends on which Al Qaeda you are talking about. ",
"\"Radical jihad has not been global for long. Even the \"Afghan Arabs\" who fought the Soviets in the 1980s generally saw themselves as training to confront enemy regimes back home. It was not until the mid-1990s that Osama bin Laden launched the globalist strategy of giving priority to attacking the \"far enemy\" in the West. Later still, Ayman al-Zawahiri reversed his long-standing concentration on the \"near enemy\" (the Egyptian regime), joined forces with bin Laden, and became number two in the al Qaeda hierarchy. \"\n\nAfter Reagan pulled out of Lebanon in the wake of one suicide bombing and Clinton left Somalia, Bin Laden saw the USA as a paper tiger; whereas the domestic regimes were seen as only being able to crush the rise of Islamist governments because they were supported by the USA. The logic was (up until 9/11): scare the far enemy into pulling support for the near enemy with attacks and the illegitimate regimes will collapse. This strategy seems misguided and a miscalculation, setting aside the obvious ethical problems.\n_URL_0_",
"As I understand it (I'm far from an expert), Al Qaeda is one of the more recent strains of a pan-islamist reactionary movement aimed at ending the state of de facto subjugation of the Arab world by western powers and extirpating their influence in the heartlands of Dar al-Islam. Remember that the islamic world stood as one more or less unified domain for the better part of 1,500 years, and for a great part of that time their empires were more advanced than the west. It's only been one century since the Ottoman empire was dismantled, after all.",
"A common mistaken assumption is that all of these militant groups we find in the Third World are fighting for some well-thought out political agenda. In reality, many of them are glorified bandits, their leaders fighting for a much more shallow business interest (ie control of diamonds or coltan), and their ranks populated by easily misguided young men without many more productive opportunities in life. For that last reason alone, it could be hard to disarm them (ie put down their guns, so they could do what, dig dirt instead? In 100F+ heat, shitty pay?)",
"TIL nobody knows who the Al Qauda are, nor who they're fighting for",
"Why don't you ask mr. Bin Laden himself\n_URL_1_\nTL:DR \nIsrael\nhere is some guy explaining it really nice ex CIA\n_URL_0_\nnoone is going to blow himself up because girls go to school ",
"So that they can be in charge and be as corrupt as those who are already in charge. Simple they want power and will do anything to get it.",
"Watch the BBC documentary called \"the power of nightmares\"",
"They want everyone to be muslim and date goats.",
"It's important to point out, as well, that the type of Islam that Al Qaeda wants is a variant called Wahabism. Wahabism is, more or less, a strict and by most views corrupted vision of Islam. It is against anything western, as well as entertainment, education (unless it is Wahabi teachings), increased female roles in society. \n\n_URL_0_",
"Mos Def asked a similar question to Christopher Hitchens and Salman Rushdie on Real Time with Bill Maher. [Watch](_URL_0_) their reply.",
"They fight for the legitimacy of the American military industrial complex, and it's right to exist.\n\nOh - you wanted a serious answer: They hate us for your freedoms.\n\n/s\n\nOn a really serious note, everything you've been told about the \"War on Terror\" and 'al qaeda' is a lie. Made up. Why do you think everything that happens in the terror world somehow goes full circle in supporting US interests? ",
"Read up on [Sayyid Qutb](_URL_1_) and [Ayman al-Zawahiri](_URL_0_). Qutb is the idealogical father of al-Queda, and Zawahiri was his best student and has been leader of al-Queda since 1998. bin Laden was just the money man and propaganda tool. The goal was to establish a world-wide caliphate under their interpretation of Sharia law. This was established 25 years before al-Queda was formed in 1988.",
"What was the Spanish inquisition for? (you don't follow my religion to the letter so now you must DIE!)\n\nYes, the US, went to their aid to help to defend against Russia, but to insinuate they're mercs hired by the CIA.. is just plain stupid. \n\nIt was simply a case of the old enemy of my enemy thing. \n\nHopefully, some day, we can just agree to disagree and be satisfied with some people believing A. some B, and some C.. personally, I'm a strong believer in Z!\n\nCan't we all just get along?",
"Wow. The comments here are mostly really wrong and ignorant.\n\nHere is what they want:\n\n1. US troops out of Saudi Arabia because it's a Holy place for Islam.\n\n2. An end to US support of Israel in the form of military aid and vetoes of UN resolutions against Israel. The US is one of the five veto powers in the UN and regularly vetoes general assembly resolutions against Israel. \n\n\nThey want other things too, but that is what they want specifically from the United States. ",
"Something I've always wondered. Being a Canadian and someone who pays little attention to the news here nor there. \n\nDoes the average member of Al Queda want me dead? Do the organizations?",
"The various terrorists will often create long and sometimes silly lists if demands, but it all basically boils down to one thing: the spread of western culture. The western culture bug has bitten countries all over the world, and it's reaching the middle east, much to their dismay. Ideas like women's rights (or allowing them to show their faces at all), free markets, individual liberties, consumerism, religious freedom, gay rights, the whole enchilada. It very much bothers them to see their youth thinking and acting in ways that aren't in line with their culture, and they point the finger of blame at America, who is sort of the poster child for western culture. \n\nThe sad thing is that before 9/11, it was a very, very small group of people who 1) hated western culture that much 2) blamed its spread on America, and 3) were willing to resort to terrorism to fix it. But after 9/11 and our massive invasions every which way in the middle east, Al Qaeda suddenly had a perfect recruitment tool, saying \"Look at what America is doing to your cities and governments! They must be stopped at all costs!\" Because this makes a much more compelling argument that \"our kids are copying American TV so let's blow shit up\", their numbers multiplied in the years following. \n\nTl;dr: It started as an intimidated hatred of American culture, but turned into a hatred of America's actions in the middle east. ",
"There was a redditor who wrote an interesting book that helps to explain Al Qaeda. It's called Tremble the Devil:\n\n_URL_0_",
"The bigger al qaeda is an invention by the US white house kept alive by the state department and it's accepted by various group in the middle east because it sounds kick-ass. It's just a general term for islamic militants.\n\nThere is actually a 'real' al queda now though, as in an organized cooperating grouping, but for some reason media are told to play that down and ignore it. it's ISIL, you can see their recognizable flag everywhere from the fighters in syria to the videos from boko haram and libya and mali.\n\nAnd now it's best for everybody including me you downvote me into oblivion. Thank you.\n",
"easy answer: US foreign policy",
"Al Qaeda is a jewish creation so we can fight wars for Israel. Here are some Jewish folk pretending to be American Al Qaeda. \n\n_URL_0_",
"To replace everyone's religion with their own by force. And kill people who dont agree with them.",
"Controlled and funded by the CIA through Saudi Arabia, acts as a platform for western involvement in the east. First it was the communists, now its the Muslims. ",
"Whatever the CIA tells them they are fighting for I'd imagine.",
"Back pay from the CIA. They are particularly upset with Orrin Hatch.",
"If the intention of the question is to understand what motivates fundamentalist groups like Al Qaeda then a better question would be 'What is Al Qaeda fighting *against*?' and the answer is not, as has so often been simply portrayed, 'our freedom'. I'm not setting out to apologise for these groups or demonise the West but it is naive to think they appeared out of nowhere, hellbent on world domination, as others in this thread have suggested. \n\nThese groups are a violent reaction to Western secular modernisation and globalisation in the language and conceptual framework of Islam. Their emergence can also not be separated from the geo-political meddling of Western States in the region and the legacies of European colonialism.\n\nA simple illustration of this point is the fact that the Nigerian Al Qaeda affiliate is called 'Boko Haram' meaning 'reject western teachings'. They are not called 'build Muslim empire'. \n\nSome context because we can't know nutin' without some context -\n\nThe Muslim world was at times through history more advanced than the West, it was a proud civilisation then was colonised by the more advanced European societies which was has left a major scar in the collective Muslim/Arabic consciousness. Imagine being told that your ways of life, your practices, your knowledge systems were backward and 'exotic'. \n\nFastfwd to 20th century - decolonisation and the rise of Arab Nationalist dictatorships. \n\nFundamentalist 'political Islam' is a modern phenomenon that has emerged in opposition to Arab Nationalism. The roots of Al Qaeda can be traced to the 20th century political Islam movements like the Muslim Brotherhood in Egypt which formed in the 1920s as an alternative model and opposition to the ruthless Arab Nationalist governments that took over after the European empires collapsed. These Arab Nationalist governments (think Assads Syria, Mubaraks Egypt or Saddam Husseins Egypt) were secular one party states and while they were ruthless to their opposition they help to understand why 20th century Arab world wasn't torn apart by war. \n\nThese secular regimes were supported throughout the 20th century by the West and set about modernizing their respective countries and in large part did so. For much of the 20th Century countries like Syria and Iraq were in many ways egalitarian, modern nations with high literacy rates and good healthcare etc. \n\nBut they did not take kindly to opposition and despite being secular religion remained central to the way of life of many of the people in the region and became the language and framework through which opposition became organised and articulated. A rallying point to combat injustice for the disenfranchised. As groups like the Muslim Brotherhood became persecuted, they were radicalised and for that reason it is said that religious fundamentalism was born in the dungeons and torture chambers of the likes of Nasser's Egypt.\n\nFastfwd to the 80s and 90s and the west is propping up all sorts of dictatorships in the region, there is the situation in Palestine and so on. The Russians are at war with the Mujahadeen in Afghanistan, the latest of thousands of years of wars with foreign invaders etc. More than anything at this time the Islmaic thinking and indigenous practices were under threat as the 'McDonaldisation' of the world was well underway. \n\nEnough to really grind your gears - look at peaceful Muslim countries like Indonesia (the worlds biggest Muslim country) there isn't fundamentalism there. It is the product of war, foreign domination etc. \n\n\n\n",
"The American military industrial industry.",
"The fourteenth century. ",
"Nobody ever explains much in ELI5 like ELI5 should be.\n\nSo for argument's sake, I'm going to explain it like your five.\n\nal Qaeda is a Muslim religion group composed mostly of male believers. They believe in using all manner of extreme violence to get their message across.\n\nThey hate Western Culture. They hate the United States and they hate, more than the United States, Israel. Jews to al Qaeda are the worst and since the USA supports Jews, they hate the USA. They also hate the USA for being in the Persian Gulf.\n\nSo al Qaeda nas vowed to bring American soldiers to the Middle East to fight them in any way they can, which includes blowing up children so they can blow up soldiers.\n\nTheir leaders are cowards and instead of coming out in the open, they recruit many illiterate, poor people to commit the acts they want, such as suicide bombers. They then promise them if they do what they need, they'll help their families, which is a lie.\n\nAnd to any potential al Qaeda member reading this. Just remember that 'Great Satan' who you hate so much, you're using his Internet, his Reddit, his E-mail systems and his computer codes to communicate. \n\n",
"Al Qaeda - literally 'the base' - a reference to the CIA covert offensive operation against the USSR in Afghanistan in the 70's/80's and specifically the US training facility set up there at the time. I know what you're asking but literally and factually speaking Al Qaeda is the proxy militia of the CIA. Always have been. From Afghanistan to Bosnia to Saudi Arabia (9-11 operatives were nearly all from there remember, not Afghanistan) and now Syria and Lybia - they will be around as long black ops are in the budget and drugs are illegal.",
"Al-Qaeda was created by the CIA through Victor Brzezinski in 1979 in order to fight the Soviets. \n\nSince then the power elites in the West and the USA particularly have been using Al-Qaeda(which as former British foreign minister Robin Cook said is nothing more than a database of known mujaheddin and arms smugglers that were created by the CIA in the first place) to overthrow foreign governments and use that as an excuse to take away rights and freedoms at home all in the name of security. \n\nThe terrorist threat is mostly fake, and what little real threat there is is insignificant as you have 5x times more chance to get hit by lightning than die in a terrorist attack. \n\nMost terror attacks are staged and/or provocateured. To know more research **FALSE FLAG OPERATIONS** and do some research into operation Gladio, Northwoods and Gulf of Tonkin.",
"Al-Qaeda is now not just the group that bin-Laden created and led in the 90's and early 2000's. It can now be very crudely divided into the few remaining core members left and then its franchises. I will focus mostly on the former because the later have mostly local grievences.\n\nAl-Qaeda proper, the group founded and lead by bin-Laden and later his successor, Ayman Al-Zawahiri, gave many a rambling sermon regarding his grievances but the most important of them were political in nature. \n\nHe viewed many of the regimes in the Middle East as particularly beholden to Western interests or even puppets of them because of the oil they possess.\n\nFor instance, the US used to base a number of troops in Saudi Arabia. Bin Laden and Al-Qaeda demanded that the US leave the peninsula, the land of the two holy places and surely not ground where troops of a secular, capitalist, power should be housed.\n\nAl-Qaeda and similar groups, it should be noted, view the corrupt regimes of the Middle East as just as bad if not worse than the US and Western Europe. But they also proffer that the US and Western Europe does much to keep those corrupt regimes in power, not a ridiculous claim.\n\nAl-Qaeda also, at least nominally, fights for justice in the Israeli-Palestinian conflict. I'm unsure what their exact demands in this regard, but its safe to say they take issue with how Israel has conducted itself since its inception. \n\nVery simply, Al-Qaeda proper fights for the liberation of Muslims from the corrupt, US-backed regimes of the Middle East and the conclusion of the Israeli-Palestinian conflict which would be extremely favorable to the Palestinian people.\n\nIn a way what they demand is not so crazy. In fact many of the regimes in the Middle East ARE at least partially reliant on US assistance (military, not economic if we're talking about the Gulf) and are extremely repressive and corrupt. Additionally, any fair observer would say that the Palestinians have been pretty screwed over by Israel. \nOf course, what they want to replace the regimes with (a probably very repressive theocracy) would probably be no better, if not far worse, than the regimes already in place. Additionally (obviously), the tactics they employ are despicable. \n ",
"The foundations of al-qaeda were laid back when russia invaded afganistan - which was run by a group of people called the taliban. \n\nthe usa wanted to help the taliban defeat the communist russians - so they asked pakistan to act as a go-between and supply weapons and training to the taliban to help stop the march of the red russian army. it worked!\n\nthen iraq invaded kuwait. thinking they would also try to invade saudi the americans sent armies to saudi to help stop saddam and liberate kuwait. thus by gaining alot of powerful oil owning friends.\n\nosama argued that americans should not be allowed to defend saudi and instead take his taliban and do it. he was eventually assured that once saddam was stopped the americans would leave. \n\nsaddam and osama had very different thoughts on how islam should be. needless to say they didnt see eye to eye. \n\nso end of the war osama said the americans should go back now. the americans refused saying it was in the interests of the region for them to maintain a presence. the saudi govt also said this going back on the assurances they gave to osama. \n\nthe heirarchy was already set of al-qaeda in the form of osama and the taliban. he'd already proved himself as a very able general of a rag tag army and as such changed the objectives to troubling the americans to leave the saudi.\n\na fair few rich saudi's agreed with him and bank rolled the process. some saying that this money was also being given to him by none other than the saudi govt. \n\nthe al qaeda of today is now fighting to \"protect\" islam but only the islam that matches their school of thought. the top tiers of power have long been removed and now its a free for all al-qaeda with many factions that rarely talk to each other as one but still go under the same umbrella and some are put there by the media",
"DURKA JUERKA MUHHAMED JIHAD ALLAH FUK AMERIKA ",
"They're devout Muslims. Islamic theology commands that Muslims are supposed to fight the infidels until Allah's religion reigns supreme over the entire world. They want to overthrow governments that they view to be un-Islamic so that Islamic theocracies based on Islamic Sharia law can be erected in their place. They then want to unite these Islamic states under a Sunni Islamic empire called a Caliphate. Then they want to invade the rest of the world through imperialist jihads and force every single man, woman and child on this planet to live under Islamic Sharia law. \n\nThey also support mass Muslim immigration to infidel countries for the purpose of [subverting](_URL_4_) them from within and growing 5th column Islamic enclaves. \n\nThey believe that this ultimate global victory for Islam will bring on the end of days where the prophets of Islam like Jesus (they believe that Jesus and Old Testament prophets were actually Muslims whose teachings have been twisted by Jews and Christians) will come back to the Earth, destroy all of the Christian crosses, slaughter all of the Jews and send the disbelievers to hell and the good Muslims to heaven. \n\nThis isn't just al Qaeda ideology. This is orthodox Islamic theology. Which is why Islamic terrorism is so [common and widespread](_URL_3_) throughout the entire world. Muslims are just currently too weak to wage conventional imperialist jihads like they did in the past (the Caliphate was also abolished after WWI). That's why they've resorted to terrorism, insurgencies, unconventional warfare and various sorts of dawah (spreading the faith through aggressive and sophisticated proselytization) and taqiyya (lying to infidels when in a position of weakness for the purpose of cloaking their true intentions and protecting the cause). \n\nWatch some [lectures](_URL_1_) or read some of the [books](_URL_0_) by the much-maligned Robert Spencer of [Jihad Watch](_URL_2_). He's a courageous beacon of light on this issue. He's one of the few Islam experts with the courage to expose Islamic theology for how depraved it really is. He also exposes how the subversive Western Left [are in bed](_URL_5_) with Muslims. ",
"they're not. they're just an excuse for america to inflict imperialism on and rob countries of their resources worldwide, while trying to scare the shit out of americans into rationalizing said robbery. Also, we're backing al-qaeda in syria. It wouldn't surprise me if a bunch of the dudes attacking places and claiming it was al-qaeda are CIA spooks.",
"If you rearrange the letters in Al Qaeda, it actually spells out 'excuse we made up to perpetrate and prosper off of the military industrial complex on a global scale while keeping it ambiguous enough for the general complacent public to not question' -- somehow seems like extra letters got in that word jumble somehow, but you get what im sayin... ",
"Their right to party. Obvious.",
"I'm just wondering why they thought it would be a good idea for Al-Qaeda to attack via 9/11 if they wanted the U.S. out of their country. Did they not expect the U.S. to wage war?",
"The overarching goal of Islam is to Islamify the world. Their adherents follow the word of a 1400 year old delusional war monger. Please spare me your absolving of Islam by pointing out the deficiencies with Christianity or other religions. All religion is insane but Islam has a special place for itself on crazy bus.\n\nSource: I'm of Turk descent. Turkey is the most moderate, liberal an sensible muslim nation and among the younger generations Islam plays a minimal role in our lives but even we still have our islamist lunatics.",
"Nothing. There is no such thing as an Al Qaeda. Now, step away from the window. And go back to sleep. ",
"It used to be the expulsion of all non-Muslims from Arabia. Now, everyone who wants some publicity link themselves to the group and thus the goals are no longer set.\n\nEveryone has their own goal.",
"cia...that was pretty simple..",
"There is no Al Qaeda. There are of course militant groups that use that name. Our military industrial complex doesn't use that name in serious discussions. Of course the media uses that name. Politicians do.",
"First and foremost, they want US troops out of the Arabian Peninsula (specially Saudi Arabia/Qatar/Bahrain/Jordan and so on) \nSecond they want to remove the current Saudi kingship and replace it with more austere and hard-line form of fundamental Islamic rule (Salafi ideology).",
"Seriously? No one?\n\nEnemy of my enemy....\n\nAl Qaeda was original funded by the US government to fight our enemy (Russia) without directly intervening during the Afghan soviet War. We gave them weapons and money. That's how they went from small time \"community watch\" organization to multinational super cell.\n\n\n\nthis was our original intention, obviously. \n\n\nJust google it or watch Charlie Wilson's war if you find it hard to believe.\n\n",
"In addition to the commentary here, also consider anything by Michael Scheuer on the subject.\n\nI also highly recommend Faisal Devji's \"Terrorist in Search of Humanity\".",
"I don't think they know, now that [Iris is dead](_URL_0_).",
"the right to party!",
"Their goal is to rid the Islamic State of western influences. Therefore they must destroy the \"infidels\" (Western People/Culture) that is present in their native land, to re establish a true Islamic State where man made laws are replaced by religious and traditional secular laws aka Sharia Law. ",
"A [serious] tag would be nice. \"The right to party\" being every other comment is pretty fucking stupid.",
"Mustard. They love mustard. ",
"I don't think terrorists really fight \"for\" something, they rather fight against something.\n\nWhat counts with terrorism is the means not the ends. Al qaeda is big so they can shape their ends in whatever form they want to reach their goals and especially recruit people.\n\nI think overall Al qaeda is against american imperialism in general and how influential, powerful, christian nations tend to cause trouble to smaller poorer countries, which is an easy, simple, short, efficient opinion to get around with in the recent years, especially with situations like Israel, the 1991 Iraq wars, Iran plots, and how the US in general replaced some small governments.\n\nUnfortunately, some politicals beliefs of al qaeda can be matched with anti-imperial, anti-american sentiments throughout the world. Only of course, al qaeda uses money and violence to reach those goals.\n\nYou could say they fight \"for\" a muslim world, but I think they use extreme religious groups as a mean to recruit and indoctrinate people (extremism works pretty well on people with a lack of proper education), pretty much like the same political tactic any revolutionary like Fidel Castro used to get in power.",
"To put it really, really simply - they want to convert anyone who will listen to their absolute, stone age, literal interpretation of Islam, kill anyone who doesn't and their punishment for ignoring them is death.",
"For the C.I.A.",
"Shifty humans doing shifty human things because other shifty humans want to force their shifty human things on them and don't want to have the first group of shifty humans to force their shifty human things on them.\n\nDamn auto correct shifty=shitty",
"Whatever CIA tells them to",
"Also.. It is my understanding that one of the pillars of islam is preservation of the faith. Western influence is seen as a corrupting factor so radicalized faith groups (ala al qaeda) use particular tactics in an attempt to fight back (ala terrorism).",
"Imagine what you would do if there were numerous bombings in the US and your family was blown to pieces for nothing other than the invading force wanting to show they have the power to do so and to possibly target someone who you barely knew that had contact with someone who had contact with someone who they did not like.\n\nI am sure that most Americans would come out fighting and use guerrilla tactics to seek revenge against the enemy.\n\nAnyone can become a terrorist , at the moment a terrorist is described as anyone who either fights against insurgent american or allied forces or plans attacks in retaliation for their family being bombed into tiny pieces, how would you feel if Russia had the power to do what America is doing now in the middle east on American soil , having bombing runs on LA and San Fransisco and targeting schools and residential areas, how would your mind be twisted if walking home you saw babies bodies in pieces next to other children and woman's body parts and you recognized some body parts as those that belonged to your baby and wife and pre teen children. You would lose it and do anything to retaliate. Now imagine that this happened to you and those around you on a daily or weekly basis with no way to retaliate.\n\nThis I believe is one reason for terrorists, but then again many are funded by Saudi Arabia and Iran just to mess with US forces.",
"Al Qaeda is a group of particularly powerful people, who have a distorted interpretation of the Qu'ran. Their belief is that Allah is the only true god, (a reasonable belief, lots of christians and other religious people have similar beliefs) but they also believe that everyone should be Muslim, and they preach a global Jihad. Jihad can be interpreted in a number of ways, and most sensible muslims believe it to be a inner spiritual struggle. However, islamic extremists quote it as a \"holy war\" against \"the enemies of islam\".\n\nHowever, a lot of the people who fight for Al Qaeda do not have such archaic interpretations; they become members of the movement as it is one of the only ways to fight back against western powers who have been having their way with the middle east for years. Al Qaeda uses these people, preaching extremism to them, some of which is not even loosely based on the Qu'ran, manipulating them into terrorism and genocide.\n\nThe sad thing is, a lot of the people who turn to extremism are perfectly justified in their misery and desperation. It is up to the western countries (not just the US, but especially the US) to stop committing atrocities in the middle east, as all they are doing is fueling more hatred in the people who live there; who are in danger of turning to extremism as a potential solution.\n\nBasically, what Al Qaeda want is everyone to think the same way as them. By no means, should my opinion or your opinion of Islam be tainted by those who misuse it to manipulate people.",
"still doesn't matter, they are all anti-Merica faggots\n\n\n'Merica",
"A terrorist born Al Qaeda is not real. It is our creation in order to have an enemy to fight just as the Red Scare was not real. Business of war is the most profitable business and there are those that have become very rich off the blood of those that have died on both sides of this business model \"conflict\".",
"Al Qaeda is fighting for he CIA",
"There is no ELI5 for this sort of question, but I can try. \n\nAl Qaeda, specifically the more current active cells, have become more of an idea than an organization. This idea is more 'apparent' in one of their newer names \"Islamic State of Iraq and the Levant\". These organizations will traditionally have a extremist and political front (ie, the Nusrah Front in Syria and ISIL). It's also important to remember that AQ is Sunni Islam who are in a continuous battle against Shia Islam and western influence. Think of it like Republicans VS Democrats in the united states, there is a history of not getting along, but they both dislike Communism. So while they both fight each other, they are also against the spread of communism. Extremist Muslims will look for anything that might be seen as an act against their people. (ie, replacing a powerful position with a Shia when it was a Sunni leader previously)\n\nIn addition to these conflicts of interest, you also have major government support from different countries because it secures your borders and/or spreads your ideology. Iran who likes the idea of Shia Islam and Saudi Arabia who likes the idea of Sunni Islam. \n\nSo you could say that Al Qaeda is a way of life that Extremist Sunni's are willing to fight for. They use media to their advantage to show how oppressed they are and bait law enforcement into killing them so they can continue to recruit based off of this idea. As mentioned many times in this thread they desire a Caliphate, but it's an impossible destination because there are too many different ideas on how it would function and thus violence is the answer, because democracy doesn't change your religion and beliefs. ",
"Please do not downvote me until you have read the research and formed an opinion yourself:\n\n_URL_4_\n\n_URL_3_\n\n_URL_7_\n\n_URL_2_\n\n_URL_1_\n\n_URL_5_\n\n_URL_8_\n\n_URL_6_\n\n_URL_0_\n\nTL;DR\n\nAl-Qaeda is fighting for whatever the CIA and the intelligence agencies want them to fight for, there is a lot of controversy over the actual legitimacy of the group as a whole. For no one has ever truly seen Al-Qaeda outside of what the Military Industrial complex corporately funded media machines tell them is Al-Qaeda, even though it very well may not be that group. It's a walking contradictory logical fallacy; and yet people swear up and down that they are the biggest threat to something because that's what the TV told them. I was tricked too!\n\nAll in all Al-Qaeda is simply a media and intelligence community creation used to steer public opinion for the War on (of) Terror.",
"The truth is being downvoted. They are created by the intelligence community as a cog in the machine. They are smoke and mirrors. \"\n\nAnybody saying otherwise has bought into the agenda and are compromised. ",
"_URL_0_\n\nWatch it.\n\n_URL_1_\n\nWatch that too.",
"For the right..... TO PAAAAAARTY! ",
"\"The United States of Fear\" is an excellent read on this issue. Highly recommended! ",
"Firstly, Al-Qaeda was made up by the American neo-cons post 9/11 to create an umbrella term for the \"terrorist network\" - Binladen never actually used the word Al-Qaeda.\n\nSecondly, Al-Qaeda is basically fighting for Islamic fundamentalism. They detest the western standard of living and seek to uphold the Quran as the political/social/economic standards by which we should live.\n\nI've just written a 3000 word essay on Islamic fundamentalism, if you need any further information I'll be more than happy to send you my bibliography.",
"The same thing the United states fights for, control. Since you know._URL_0_",
"This was a great question. I now understand a lot more about what's going on in the middle east. Thank you, bunnyhopskotch and thisisntnamman.",
"There are two types of organizations in this world (I'm generalizing because it's not really so black and white) -- those who want to see everyone get along with each other and grow as a species, and those who want to have control and power.\n\nHaving control and power in a small group or leader is starting to slowly become a little bit antiquated. Think back to the time of kings and queens and dictators. They want to rule their kingdom the way *they* want.\n\nNowadays, we have to learn to work together to take care of our planet. There's a physicist called Michio Kaku who talks about different types of civilizations. A type 0 civilization is one that still has civil wars, famine, uses fossil fuels and other planetary resources. A type 1 civilization is one that is peaceful, harnesses the power of the sun, controls the weather, etc.\n\nWe're on the verge of either becoming a type 1 civilization, but there are still lots of people who want to be dictators and rule people. These types of people are terrorists. Very simply put, Al Queda is a group that wants to control people instead of see everyone get along peacefully."
]
}
|
[] |
[] |
[
[],
[
"http://www.theguardian.com/world/2002/nov/24/theobserver"
],
[],
[
"http://m.foreignaffairs.com/articles/61144/l-carl-brown/the-far-enemy-why-jihad-went-global"
],
[],
[],
[],
[
"http://www.youtube.com/watch?v=95ncn5Q16N4",
"http://youtu.be/UXOslH6aM1E?t=48s"
],
[],
[],
[],
[
"http://en.wikipedia.org/wiki/Wahabi"
],
[
"http://youtu.be/fkmQpqCMyHc?t=42s"
],
[],
[
"https://en.wikipedia.org/wiki/Ayman_Zawahiri",
"https://en.wikipedia.org/wiki/Sayyid_Qutb"
],
[],
[],
[],
[],
[
"http://www.amazon.com/Tremble-Devil-Anonymous-Author-ebook/dp/B004R1QBN8"
],
[],
[],
[
"http://youtu.be/GsUtvOW6SR0"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://www.amazon.com/The-Truth-About-Muhammad-Intolerant/dp/1596985283",
"http://www.c-span.org/video/?199391-4/book-discussion-politically-incorrect-guide-islam-crusades",
"http://www.jihadwatch.org/",
"http://www.thereligionofpeace.com/",
"http://www.discoverthenetworks.org/viewSubCategory.asp?id=1235",
"https://www.youtube.com/watch?v=Cu4UAG3XHIE"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://www.youtube.com/watch?v=9OVv-J-LXQU&feature=kp"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://www.democracynow.org/2004/6/10/ghost_wars_how_reagan_armed_the",
"http://newsone.com/1205745/cia-osama-bin-laden-al-qaeda/",
"https://www.youtube.com/watch?v=g8mvjLgt7Hg",
"http://www.theinsider.org/news/article.asp?id=0228",
"http://en.wikipedia.org/wiki/CIA%E2%80%93al-Qaeda_controversy",
"http://www.washingtonsblog.com/2012/09/sleeping-with-the-devil-how-u-s-and-saudi-backing-of-al-qaeda-led-to-911.html",
"http://www.whale.to/b/alqaeda.html",
"http://www.globalresearch.ca/al-qaeda-and-the-war-on-terrorism/7718",
"http://www.rense.com/general73/cia.htm"
],
[],
[
"https://www.youtube.com/watch?v=h8Lam9V_9tE",
"https://www.youtube.com/watch?v=Cjtb22sxSuc"
],
[],
[],
[],
[
"https://www.google.ca/url?sa=t&source=web&rct=j&ei=nkCLU66hEoGP8gGzj4B4&url=http://www.youtube.com/watch%3Fv%3DDqn0bm4E9yw&cd=1&ved=0CCkQtwIwAA&usg=AFQjCNH1LjzZPH-QeV53F9g_IWt4y7o6IQ"
],
[],
[]
] |
||
4gzeho
|
why does styrofoam melt when it comes into contact with superglue/adhesives?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4gzeho/eli5why_does_styrofoam_melt_when_it_comes_into/
|
{
"a_id": [
"d2m1s9x"
],
"score": [
12
],
"text": [
"Super glue and other adhesives contain some organic solvents (e.g. acetone, ethyl acetate). Styrofoam is made from thousands of styrene molecules linked together. Styrene by itself really wants to dissolve in these organic solvents, but since so many of them are linked together it can't because it's simply too big. So instead of dissolving, you get melting effect."
]
}
|
[] |
[] |
[
[]
] |
||
1y9sro
|
how do services like pandora and spotify work
|
I was wondering how a service like Pandora makes money if they have to buy the rights to all of the music that they have. When as far as I know not many people purchase the paid version. Same thing applies to Spotify.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1y9sro/eli5_how_do_services_like_pandora_and_spotify_work/
|
{
"a_id": [
"cfikt4r"
],
"score": [
2
],
"text": [
"same way any business operates. sell it for more than you buy it.\n\nif it costs $10,000 for Pandora to buy the rights for a song, and they play it on 1million users and get advertising $0.01 per play, then that's profit."
]
}
|
[] |
[] |
[
[]
] |
|
21c9ta
|
putting down animals in zoo
|
why do Zoo put down healthy animals? for example in Denmark recently they put down healthy giraffe and 4 lions
thank you for answer
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/21c9ta/eli5putting_down_animals_in_zoo/
|
{
"a_id": [
"cgbnak5"
],
"score": [
4
],
"text": [
"Did you read the rest of the article? They explained exactly why they did it.\n\nThey didn't have the money to relocate the animals, and the new animals they were getting would have killed the old animals -- euthanasia makes a little more sense than a zoo snuff show.\n\nIt's more important to look at the population of the species as a whole than any one individual animal -- with regards to the species as a whole, the zoo was doing exactly what it should."
]
}
|
[] |
[] |
[
[]
] |
|
a2ai3x
|
why is it easier to fall asleep to background noise (radio, tv etc.) than just the plain dark?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a2ai3x/eli5_why_is_it_easier_to_fall_asleep_to/
|
{
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"eaxr19c",
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"text": [
"In my experience, a little background noise (white noise) helps cut out any outside noise that might wake you up ",
"This happens because when there's noise around us we feel that someone is near us.\nThus we feel safe and can let go of the tension and fall asleep.\nThis is an evolutionary thing and has been embedded in our DNA. Humans are primarily social animals and keep each other safe.",
"If everything is silent, you are able to hear every noise - the person walking past outside, a family member moving about and other fairly normal noises become prominent and obvious, so you hear them and have to decode them to figure out of they are dangerous - you are deciding whether you need to kick in your 'fight or flight' response and act, or whether the sound is normal and not a worry - for example whether the sound of someone walking past is your neighbor coming home from a bar late at night, or someone nefarious lurking outside your house. Is that humming noise the natural sound of the fridge, or is it something that has been left on accidentally?\n\nWhite noise (or other familiar sound) covers all of this up and let's you relax - if you cannot hear the sound of someone walking past outside over the natural sound in your home then you won't have to go through the evaluation process to determine if it is a danger or not.",
"Another reason is because of hearing damage. If you have tinnitus you might hear a constant sounds that aren’t there; often a high pitched ringing or whine. Background noise can cover this perceived sound and be more comfortable for sleeping. ",
"All of the other comments are totally accurate, but I'm surprised no one's said this: When it's completely silent, many people's brains make an attempt to fill the void with thoughts. So, instead of sleeping, you're now having an existential crisis, or wondering what would've happened if you asked that one girl out, in 3rd grade."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
c1abiu
|
how are amputees able to control the fingers in their bionic arm ?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/c1abiu/eli5_how_are_amputees_able_to_control_the_fingers/
|
{
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"erc5ykj",
"erccajx",
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"text": [
"Conventional myoelectric prostheses, what 99% of the bionic hands on the market use, are controlled by two inputs. Two sensors on the forearm (in the case of a below elbow amputee) pick up muscle signals. The amputee can either open or close the hand. Programming in the hand and using a variety of combinations of input codes can trigger different grips. For example, triggering open and close at the same time can engage one grip. Holding an open signal for a fixed time can trigger another grip. Sending a very fast/strong open signal can teigger a third grip. Same with a close impluse. \n\nWith practice, it can become somewhat natural. \n\n\nPattern recognition uses many more electrode sensors to pickup more fine movements that can directly pickup more detailed inputs from the remaining muscles, but it still is not at the individual finger control level yet. \n\nTo control 5 individual fingers of flexing and extending. You need 10 different inputs. This level of detail is only possible with inplanted electrodes. To control every joint of each finger like you can with your natural hand, you will need about 35 different inputs.",
"The company I work at actually exclusively works on this!\n\n/u/WashingtonFierce post is incorrect, we do not yet have commercial technology designed specifically to physically interact with the brain and detect limb movement. The amount of time, money, and risk is prohibitively monumental. Imagine being an ethics review board member having to review an experiment about splitting a subject's head open to insert a sensor that you may or may not know will work effectively and reliably unless you try.\n\n/u/TheLazyD0G has more or less explained it correctly, and I can add some additional info.\n\n* Your brain sends signals to nerves in the arm, and the nerves are connected to the arm muscles. What actually happens when your arm muscle contracts is a bunch of sodium and Potassium ions moving about the cell walls of your muscles. Since these ions have positive charges to them, their movement generates a very very tiny voltage. The two sensors that sit in the prosthetic socket and touch the forearm are sensitive enough to pick up this change in voltage. This concept is called [EMG](_URL_1_).\n\n* [So depending on the voltage change, the sensors can detect how hard you're flexing, or even at all.](_URL_2_)\n\n* [The way the hands are programmed are in that they cycle through different pre-set grip modes, and the patient can only open and close them in the different modes.](_URL_0_) The bebionic3, for example, you start out in Tripod grip (so you only close index, middle, and thumb) and can only close and open in that formation. You have to press the button on the back to change to Power grasp, and then you can only open and close them in a fist. You then have to press the button, AGAIN, to go into another grip, say Precision grasp, and then you can only open and close the thumb and index finger together. In a sense, they're just hand-shaped swiss army knives.\n\n\n\n* The patient opens and closes them by flexing their limb in one direction or another. Imagine flexing your wrist towards your chest. That's close. Now flex your wrist away from you. That's open.\n\n* This can get tedious (how many times did I have to press the button?) and can get frustrating if you make a mistake in a high-pressure situation (e.g. getting change into your wallet after the cashier hands it to you)\n\n* The pattern recognition that /u/TheLazyD0G mentions attempts to use multiple (3+) sensors and machine learning to have the arm change the grip based on which hand gesture you trained it to do earlier. However, this concept is still bogged down by the hand's programming of only changing between different pre-set gestures.\n\n* We have not yet achieved the level of fineness in detecting individual finger movements, largely to the concept of \"Crosstalk\". With the current size of these skin sensors, the region of muscle they observe can't distinguish whether a movement was for one finger versus another. Implantable sensors can theoretically solve this issue, but research into them so far have been very preliminary.\n\nLet me know if you have other questions!",
"Depends on the exact type of bionic arm; but in general, the bionic limbs got sensors somewhere in the body (sometimes at the stump itself, sometimes elsewhere in the body) that measures either muscle contraction or nerve/neuron activity directly and interprets the different signals into limb position or movement velocity. Some variations are more intuitive to control than others, but in general over time the person learns how to control it with a bit more dexterity.",
"None of y’all ELI5. Either that or your 5 year olds are are intellectual prodigy.\n\nAhem...\n\nNERVES AND WIRES.\n\nWe control our fingers with NERVES like we control most things in our body.\n\nNerves are like wires that go down our arms from our brain to our fingers in a bundle.\n\nIf we loose an arm by accident, the wires are still in our arm bit we still have, they just don’t go to any fingers anymore. The best doctors find the out these finger control wires... nerves... and make them go to the arm muscles on the arm bit that we still have instead.\n\nNow when we think of moving our fingers, our arm skin moves instead, just a little bit.\n\nThey make the robot arm scan the real arm where the wires have been put by the doctor to move the skin! The cup bit where it attaches has the sensors.\n\nWhen the robot arm senses the arm skin make a move, it moves the robot fingers instead!\n\nThey swap the lost human wires in the arm with robot WIRES!\n\nEDIT: Thx for the gold stranger! First one! I need to find the ELI5 for what it means now..."
]
}
|
[] |
[] |
[
[],
[
"https://www.youtube.com/watch?v=tCAgGVcxrb8",
"https://en.wikipedia.org/wiki/Electromyography",
"https://www.researchgate.net/profile/Igor_Stirn/publication/254229319/figure/fig3/AS:393234309238792@1470765773723/Energy-envelope-of-the-rectified-EMG-signal-of-LD1-of-three-consecutive-muscle.png"
],
[],
[]
] |
||
fsidc
|
I have a weird question about micro-gravity.
|
Testicles use gravity to regulate their temperature by hanging closer or further from the body.
So what happens in space? does it cause discomfort to astronauts?
Also does micro-gravity increases the risk of testicular torsion?
Are 'private' problems caused by space travel documented by space agencies?
|
askscience
|
http://www.reddit.com/r/askscience/comments/fsidc/i_have_a_weird_question_about_microgravity/
|
{
"a_id": [
"c1ibala",
"c1id1y1"
],
"score": [
2,
2
],
"text": [
"I'll attempt to answer part of this question seriously. I wouldn't know anything about the first two questions, but in terms of the third question you may be interested in [this nice Slate piece](_URL_1_) which has quite a bit of information.\n\nIn addition, you have several problems with radiation. Cosmic rays can damage male sperm -- not to the point of infertility, as many astronauts have conceived after sometimes extended stays in space -- but more importantly can seriously harm human fetuses. [Link.](_URL_2_)\n\nFinally, female rats in microgravity have rather difficult labours. [Link, behind paywall.](_URL_0_) This doesn't bode well for humans, who have rather difficult labour already.",
" > So what happens in space? does it cause discomfort to astronauts?\n\nThe testicles may ride higher in microgravity. I don't think that it would cause discomfort. Think of it this way: when lying down, gravity is not pulling the testicles downward. Is it uncomfortable to lie down?\n\n > Also does micro-gravity increases the risk of testicular torsion?\n\nIt's feasible. There is [some evidence](_URL_0_) to link torsion to colder weather. One explanation for this is that a sudden exposure of cold causes tension in the cremaster muscle, potentially pulling a loose torsion tighter. This could apply to microgravity."
]
}
|
[] |
[] |
[
[
"http://www.newscientist.com/article/mg15120381.400-space-pregnancy-leads-to-hard-labour.html",
"http://www.slate.com/id/2159265/",
"http://journalofcosmology.com/Mars124.html"
],
[
"http://www.jurology.com/article/S0022-5347\\(07\\)02056-3/abstract"
]
] |
|
3srgnb
|
why haven't we seen the us (and its partners in the fight against isis) engage in a siege of raqqah, the "de facto capital of isis"?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3srgnb/eli5_why_havent_we_seen_the_us_and_its_partners/
|
{
"a_id": [
"cwzsrkg",
"cwztb2d"
],
"score": [
7,
17
],
"text": [
"Isis doesn't wear uniforms, man. They blend in with civilians, that is their defence tactic. Raqqah has a population of like 300k, how many more innocents need to die ?",
"1. Raqqa is surrounded by other territories controlled by Islamic State, so to surround it you need to fight IS on at least two fronts (both sides of the Euphrates).\n\n2. Any effective form of siege could have to involve cutting off food, water, or electricity, which would result in massive civilian casualties and would be a PR disaster. Remember, IS is already surrounded by countries that are hostile to it, the softest of which is Turkey which still tries to prevent them from using the border. They manage to get weapons and soldiers despite this.\n\n3. No one wants another war. America is tired from Iraq and Afghanistan, and Russia still has bad memories from Afghanistan and Chechnya.\n\n4. Surrounding Raqqa would involve putting American troops in Syrian soil. America does occasional special forces raids into Syria (two that I can think of off the top of my head), but long-term troop deployments is something else entirely. It would be a diplomatic nightmare.\n\n5. Raqqa is arguably not the most important city in the Islamic State. Their military equipment is spread everywhere, and the city of Mosul is larger and more important. Raqqa is only the capital because it is the first big city they captured. \n\n6. There are already powerful groups fighting ISIS, including but not limited to: Jaysh al-Islam, the Army of Conquest coalition, Iraqi government, Syrian government, the SDF and New Syrian Army, Iraqi Kurdistan, YPG, PKK, FSA, and Hezbollah. For foreign governments, it is easier to simply support one of these groups with weapons or airstrikes. "
]
}
|
[] |
[] |
[
[],
[]
] |
||
1lsovb
|
Was there any ethnic tension between Germans, Slovaks, Slavs, etc... in the early 1900's and leading into the second World War? If so, what was it like?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1lsovb/was_there_any_ethnic_tension_between_germans/
|
{
"a_id": [
"cc2ehla"
],
"score": [
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"text": [
"Of course there was. In the early days of Czechoslovakia, tensions between Czechs and Germans were a major issue that would later play a part in the months preceding the Second World War and the occupation of Czechoslovakia, and that would only be resolved until after the war. And even then only via the highly controversial Benes Decrees.\n\nGermans have lived alongside Czechs (or Bohemians and Moravians, if you will) since the earliest days of a Czech state, colonizing parts of it from about the 10th century onwards in what we now call the Ostsiedlung - settling of the east. This was caused by both a growing population in German lands as well as local rulers actually welcoming and encouraging settlers to come to Bohemia.\n\nHowever, after the Habsburgs had taken over some centuries later, Czech lands have been subjected to gradual Germanization and German culture as well as language became the norm for upper classes, politics and the like. This in turn led to the advent of nationalism and the Czech National Revival, a story that ought to sound quite familiar to many nationalities all over Europe around the 19th century.\n\nFinally this leads us to the end of the Great War, and the dissolution of Austria-Hungary. The multiethnic monarchy had faced calls for independence or fair representation in politics from its constituent nations for quite a long time now, and the war had only postponed the resolution of these issues. Austria-Hungary did not survive, after the war, Czechoslovakia and others have declared independece and the empire soon ceased to exist.\n\nThis is where things get rather interesting. The idea of a Czechoslovak nationality is an artificial concept promoted by the leaders of the independence movement and future presidents Masaryk and Benes. It does have its roots in reasonable assumptions as the two groups have mutually intelligible languages, are close culturally and have lived in close proximity for centuries, but ultimately it was a calculated decision much influenced by the political situation.\n\nYou see, according to the 1921 census, there were 8 759 701 Czechoslovaks (roughly two million of which were Slovaks) and 3 123 305 Germans in Czechoslovakia, with other sizeable minorities such as Hungarians. This was a direct result of the newly independent country keeping its historical borders which, however, included the regions with a sizeable German population – Sudetenland.\n\nThe Germans had actually called for some sort of exclusion from this arrangement or self-determination, such as becoming a part of Austria – indeed, in the spirit of Wilson's Fourteen Points and the general post war atmosphere that allowed various peoples to declare their independence – but the Treaty of Saint-Germain-en-Laye ended their hopes as the lands of the Bohemian Crown were preserved in their historical shape.\n\nIn the two decades that followed, the relations between Czechoslovaks and Germans have deteriorated, albeit rather slowly at first. German was preserved as an official language in areas with a considerable German population, Germans were represented in the parliament, but on the other hand Czechoslovakia was ultimately a Czechoslovak nation and many policies reflected that, such as a clear preference for Czech officials in local politics.\n\nAn important point that I feel has to be made is that although this was at a time when Nazis were on the rise in Germany, Germans in Sudetenland were not yet particularly strong sympathizers of the new regime. Henlein's separationist Sudetendeutsche Partei only came under Hitler's major influence from 1937 onwards, two years after securing 44 seats in the chamber of deputies, more than any single Czech party, and 23 seats in the senate, tied with the agrarian party.\n\nGermany portrayed the situation in Czechoslovakia as extremely untenable, Hitler made no secret of his ties to Henlein's party, with the Sudetendeutsche leader in turn exerting internal pressure on Czechoslovakia presenting mostly unacceptable demands including autonomy to the government. Besides overt political action, Germany also prepared for a military conflict if their demands were met.\n\nFaced with the possibility of war and at the same time the less than ideal German situation in Czechoslovakia, France and Britain kept with their policy of appeasement, sided with Germany, and the Munich Agreement was signed in 1938 with the Czechs not having much say in the matter, ruling that Sudetenland would become a part of Germany.\n\nIn the end the Germans in Sudetenland were a minority with many of the problems this presents for those labelled this way, as well as for those who would form the majority. Centuries of tension did not help either, nor did the fact that they were not afforded the same treatment as other nationalities when it came to the collapse of the monarchy. However, Austria-Hungary was on the losing side of the war, the Czechs had only kept their historical borders, and although their relationship was often problematic, never subjected Germans to harsh treatment minorities sometimes suffer before the war.\n\nThat everything played out the way it did was a result of the build up to the Second World War by Germany rather than historical relations and ethnic tension between Germans and Czechs in a single country."
]
}
|
[] |
[] |
[
[]
] |
||
7m4e2p
|
when did the storefront name of "arcade" go from being a kids' video-game hangout, to being an 18+ slot machine parlour?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7m4e2p/eli5_when_did_the_storefront_name_of_arcade_go/
|
{
"a_id": [
"drr9ngm"
],
"score": [
2
],
"text": [
"It happened due to home gaming consoles.\n\nOlder redditor here. I used to play the quarter-munchers back in the days before everyone with teens or kids had at least a couple game consoles... and the earlier generations were really shitty. So you'd go to the \"pinball arcade\" to play games with much better features like actual voices, graphics that didn't look like potato-splats, and... pinball.\n\nFast forward to when the average 15 year old that finds they have an interest in electronic games has their own Steam account or PS4 or XBOne, and the biggest source of quarter-by-quarter funding for \"arcades\" dried up. So, with the exception of a few that feed our senses of nostalgia, they largely went out of business.\n\nSo the word \"arcade\" was ripe for repurposing... and they did that by assigning it to legal-gambling slot machines instead because a lot of gambling addicts and participants drop WAY more money into those machines so it's a viable business mode.\n\nBut why \"arcade\"? Before it was \"video arcade\" it meant \"penny arcade\", which meant coin-operated devices. With the exception that they now use bills or tokens instead, it's still currency-operated... and so the term still very much applies."
]
}
|
[] |
[] |
[
[]
] |
||
308jls
|
what is the difference between readings books (any kind) and reading various reddit articles/threads?
|
Assuming you don't look at any advice animals or funny pics, etc. and it's all reading, what's going on in your head between the two?
Also, besides looking at a screen (blue light) and a physical book.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/308jls/eli5_what_is_the_difference_between_readings/
|
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"Reddit posts & articles are usually fairly short. There's not a lot of depth or nuance going on - especially the front page, which is full of image, memes and other such easily digestible things (not to mention all the articles that get commented on by people who never read the link).\n\nA book, or long-form article requires more commitment & attention paid to it. It's able to express more complex ideas, commit more time to them & explore themes in more depth.\n\nHaving reddit as your primary reading source is like eating candy & stacks instead of eating a full meal."
]
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9v7eea
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Was Cato the Younger a Pleb or patrician?
|
Everything I’ve read about him would indicate the later but in 63 BC he was elected to the office of Tribune of the Plebs.
When Clodious , who was from a minor patrician family, was elected to that position only 4 years later, he had to renounce his status and be adopted by a pleb family in a ceremony headed by good ol’ J.C. (Pontifex Maximus).
I have not read anything to indicate that Cato did the same nor have I ever seen anyone bring this point up but it’s been bugging me a lot. I mean Cato is pretty much a paragon of what a patrician should be. Am I missing something here or was Cato just an extremely lucky and privileged pleb?
Pls help
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/9v7eea/was_cato_the_younger_a_pleb_or_patrician/
|
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" > When Clodious , who was from a minor patrician family\n\n*Minor*?! The *gens Claudia* was one of the largest and most prestigious patrician *gentes*, outstripped only in surviving patrician lines by perhaps the *gens Cornelia*. To call Clodius a member of a minor family is like calling the sun a little hot.\n\n[You're completely misunderstanding what a plebeian (the singular of plebs is plebs, it's a collective singular) means.](_URL_0_) Patrician does not mean senator, and most senators were not patricians by far. Cato was a plebeian, like Cicero, Crassus, Pompey, Antony, Cassius, Lucullus, both Bruti, etc. The *gens Porcia* was a plebeian *gens*, and was heavily involved in the final stages of the Conflict of the Orders, during which members of the family passed several important *leges Porciae*, at least one of which protected soldiers on campaign from *coercitio* by extending *provocatio* to them"
]
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[] |
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"https://www.reddit.com/r/AskHistorians/comments/3fmn4h/what_was_the_difference_between_patricians_and/ctq0ct3/"
]
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|
1352eq
|
Why did the Irish Rebellion in 1798 fail?
|
compared to the American revolution and the French revolution which both succeeded, why did the Irish revolution fail ?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1352eq/why_did_the_irish_rebellion_in_1798_fail/
|
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"In short (don't have much time, so perhaps someone can expand on this)\n\n1. Three of the United Irishmen's top brass were arrested on the eve of the uprising.\n\n2. Artillery stationed in Ireland had been upgraded and increased in size. One Lieutenant was to describe that the 'Grapeshot (cannister) worked like a wonder'\n\n3. The rising was more of a massive rural peasant riot that lacked proper cohesion and goals. While mobs would rise in a certain area, those with leadership abilities would come to the forefront, however their attacks were limited to local barracks etc\n\n4. The United Irishmen were under-armed and were facing a fairly sizeable government army which had at it's disposal 9000 regular troops, 25000 militia and 40000 yeomanry (civilians with arms). The well disciplined regulars were more than enough to change the tide in a number of critical locations.\n\n5. While the French did land in Co. Mayo I believe it was just too late, and once again it was a half hearted attempt like every other invasion of Ireland by Spain and France to support the nationalists."
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b5s4wd
|
why can paying off your student loans hurt your credit score? it seems like it would be a good thing.
|
Any information that would help explain credit scores would be very much appreciated.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/b5s4wd/eli5_why_can_paying_off_your_student_loans_hurt/
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"Part of a credit score is being able to prove you can pay off debt, which requires having debt to begin with. That’s why people who have never had a credit card or loan generally don’t have good credit. Without any debt, you can’t prove you have the ability to pay it off, hence the lower score.\n\nTo summarize, lots of debt = bad / no debt = bad / some debt = good",
"Making payments on time on your student loans is good. Everything in your credit report ages out over time. The day you make your last payment is the local maximum for your credit score, if you don't have any other transactions. Years later, your score will be lower, because your last good report will be older.\n\nSo, if you run off to be homeless in the forest and live your life with cash, you don't have a very good credit score. This sorta makes sense, you might be an anti-social nutcase that wouldn't pay back the money if someone loaned it to you. It's not proof you are, but it's uncertainty that you might.\n\nSo, you need to make sure that there are good reports every month. And you need to relationship between the credit limit and the actual payments is favorable. There are many, many weights used in the calculation, all of which are proprietary to keep people from gaming the system.",
"A credit score is an indicator of how good a customer you would be to creditors. Part of that is proving that you can pay your bills on time, which is why missed payments or having too much debt can cause damage to a credit score. But another part of it is showing that you're actually willing to take on debt in the first place, and proving that you can manage it and pay it. So if you're ever in a position where you have no debt whatsoever, it can adversely affect your score as well. After all, creditors want to know that you'll actually be a customer - someone who never takes anything on credit is someone they'll never earn money from.\n\nThis means that there's a weird limbo where having too much debt is bad and having too little debt is also bad. If you're hoping to improve your credit score, having some debt - like a car loan or modest credit card usage - is important, because it helps establish you as a customer that people should want to lend to.",
"A [search](_URL_0_). Near but not identical threads.",
"Paying off student loans early doesn't \"hurt\" your credit score, but it does have an opportunity cost where your credit score could have been higher if you would have paid them over time. \n\nSomeone that has made consistent and regular payments for 10+ years is more valuable than someone that zeroed their loans 5 years ago and hasn't had to keep steady payments since. \n\nThe bank KNOWS the 10+ year guy can handle regular payments and has a proven track record of making sure there's always enough in the checking account to make his payments, even if they're unemployed. \n\nThe 5 year guy is probably good too, but the bank doesn't KNOW if he can keep his payments regular. For all they know he's a chronic gambler that got lucky 5 years ago and paid off his debts. If they give him a loan today he could go lose it all on black at the casino and miss payments. \n\nWith all that said, pay off your loans in order of highest interest. If you're under 30 everything you buy is going to be debt financed anyway, so you're going to be building a history no matter what. Just be smart and zero the 20% credit card before zeroing your 3% student loans. ",
"The most important thing to know here is that there's a common misconception of what a credit score actually means. \n\nMany people think it's a number that says if you repay your debts. And while that's true it's not the only reason the score exists.\n\nThe score is actually a store representing how likely the lender is to make money from you. A big part of that is the likelihood that you will default (therefore the bank loses the money they lent you). But also if you repay loans before significant interest is paid, the bank doesn't make any money off the transaction. \n\nThis is the key. Pay off your loans early and the bank won't make any money off you. That makes you a bad customer because they are not likely to make much profit. Loans always have costs, there's an innate risk but also the money they spend to evaluate the transaction and determine if they want to lend you money. If you constantly repay loans before the banks can recoup those costs, you actually become someone they don't want to lend money too!\n\nSo the credit score is a score the bank can look at and ask themselves \"if we loan this guy money, will we make a profit in the deal?\". The truth is that the actual score is far too little information for most banks and most take the actual underlying data on your credit report and use it to generate their own internal score for you as a client. But the ultimate indicator is not exclusively the risk of default, it's the potential for profit. Defult is just one element of profit potential.",
"Paying off your student loans won't hurt your credit very much, and its not something you should worry about.\n\nif you are making a payment on time every month, that shows you are reliable. Once the loan is repaid, you are no longer making a monthly payment. You might have become unreliable. Maybe you lost your job. Its hard for the bank to know. Unknown = risk. Risk = lower credit score.\n\nI don't think you'll see this affect if you have other bills and pay those bills on time.\n\n"
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cbefmn
|
What was the primary warship of the Indian Ocean before the advent of the modern period?
|
So I've been curious to how naval warfare was conducted in the Indian Ocean as I'm only familiar with the calm-water war galleys, and the modern era sailing ships of Europe.
& #x200B;
I've read that the Arabs and Indians used the Dhow to transport goods, but was there something like the War Dhow?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/cbefmn/what_was_the_primary_warship_of_the_indian_ocean/
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"One particular aspect of maritime situation in the Indian ocean in the second half of fifteenth century which is often emphasized by scholars, is the *relative* peacefulness and *absence* of large scale naval conflicts. The accent here is really on the word *relative* as piracy was abundant and there was plenty of naval combat in the form of smaller neighboring states fighting each other, or a commercial center port subjugating its immediate surroundings. \n\nBut what you won't see, is the kind of power projection across the seas, sending combat fleets far way from home, or establishment of maritime empires backed by sea domination which you might associate with, for example Italian medieval merchant states. Again, before someone gets their pitchforks out, I am mostly referring to the *fifteenth century* and the setting in place in time of European arrival. It is quite possible somewhere back in time Indian ocean was full of such naval empires, I really wouldn't know.\n\nThe following consequence of such situation is that there really wasn't much large scale naval battles (like e.g. battle of Zonchio in 1499 in Mediterrenean) and for that matter, there were no clear large dedicated warships that might be considered an analgoue to European galleys, or later galleons or ship-of-the-line. And that's perfectly fine! In fact it is probably the Mediterrenean that was an outlier as in 14th century both England and France were raising their navies by commandeer and adapting merchant ships rather then having dedicated warships.\n\nIn those conditions, the naval fleets, when assembled, had usually consisted of a number of large merchant sailing ships taken for the occasion and filled with soldiers, augmented with a large number of oared vessels. Such combined fleet of smaller oared ships together with larger merchant ships were encountered several times by the Portuguese, in their fights at Hormuz, Chaul/Diu, Malacca, etc.\n\nThe smaller oared ships could vary in size (and have a mast with a sail, same as galleys) but were as a rule smaller then galleys as Portuguese often applied the term *fusta* to describe them, and *fusta* was a European type of small galley. if anything would be considered a warship of Indian ocean, it would be these oared vessels. Unfortunately, I can't find much information on them as they seemed to pass under the radar of most works. \n\nThe merchant ships, primarily propelled by sailing would be what you term dhows. That is if we are talking about the western part of the Indian ocean - the Arabian sea - where most ships were of this type. Most of the Portuguese descriptions (sorry for dealing with Portuguese sources, but it seems those are the main sources most of scholarship draws from. Hopefully the situation has changed and I am just out of date...) describe them as well built ships built, and particularly accent that they were built without nails (actually some sources disagree, but vast majority confirm) and instead either wooden pegs were used or the planks were sewn together, another interesting feature many sources agree with. By size those ships were just as big, and on more then one occasion even bigger then Portuguese naus they were up against. Yet unlike Portuguese ships it seems that the ship board artillery wasn't really a thing. Or it was, but the artillery it self was much weaker then the ones brought from Europe.\n\nIn the eastern part of Indian ocean, there was a considerable additional influx of SE Asian designs of such large ships, which Portuguese dubbed \"junks\" (juncos). Those had some Chinese influence in origins, but were actually heavily influenced by native SE Asian design. Unlike dhows, those are much more often described as having nails and in general had a different look and feel. They also had two side rudders instead of a stern rudder, a fact Portuguese wrote down with interest as they considered it a weakness in battle. They were also larger then Portuguese ships, and had multiple layers of planking which allowed some of those junks to resist even the largest cannon fire from Portuguese ships. The ships were still at a disadvantage against the Portuguese, and seems in the early days when Portuguese conquered Malacca they also succeeded in winning most of the few naval battles they had.\n\nTo conclude here are some of the 16th century (european) images of the ships. We are not sure if those are realistic first hand accounts or just imaginations of authors back in Europe.\n\n[Ships of the Arabian sea: a dhow and a 9-masted large ship - 1519 ](_URL_0_) \n\n[Ships from Java / SE Asia: junks - 1598](_URL_2_)\n\n[Ship from SE Asia: jong/junk - 1613](_URL_1_)",
"In medieval India, the Muslim rulers (such as the Deccan Sultanates and Mughal Sultanate) had mostly ignored the naval arm of their military forces. It may be because they came overland from the North and won decisively in land battles. \n\nThis scenario changed, however, when the Portuguese arrived in India and started monopolizing and controlling trade on the western coast of the continent. Chhatrapati Shivaji (known as the father of the Indian navy) realized the importance of a strong navy; the first keel of a Maratha naval vessel was laid down in a creek near Kalyan circa 1654.\n\nShivaji took up the task of constructing multiple naval bases along the coast of present-day Maharashtra. He organized two fleets – one under the command of Admiral Mainak Bhandari and the other under Daulet Khan.\n\nThe Maratha Navy consisted mostly of native Konkani sailors; however, it was commanded mostly by mercenaries, including Siddi and Portuguese. Circa 1659, the Maratha Navy consisted of around 20 warships. \n\nHiring mercenaries was relatively common in Maratha military culture and the Navy was no exception to this practice. Portuguese naval officer Rui Leitão Viegas was hired as fleet commander, in part because the Maratha wanted to get insight into the Portuguese naval technology and capabilities. \n\nThe Maratha Navy was primarily a coastal “green water” navy, compared to an ocean-going or \"blue water\" navy. Their ships were dependent on land/sea breezes. The Maratha did not build ships large enough to engage the British out at sea far from the coastal waters.\n\nAs for the ships. here are three:\n\n[Galbat](_URL_2_): The Galbats were larger row boats but of smaller dimensions. These rarely exceeded seventy tons. They had two masts of which the mizzen was very slight. The main mast had one large triangular sail. When hoisted, its peak went much higher than the mast itself. The Galbats were usually covered with a spar-deck, made up of split bamboos for lightness. They carried only 'patteraroes' which were mounted with six or eight pieces of cannon ranging from two to four pounders.\n\n[Gurab](_URL_0_): The Gurabs had usually not more than two masts, although some had three masts. The capacity of three masted Gurabs was about 300 tons, and that of smaller ones, the capacity was about 150 tons. These warships were covered with a strong deck which was on the same level as that of the main deck of the vessel. On the main deck, under the fore-castle there were two pieces of cannon from nine to twelve pounders pointing forward through the portholes cut in the bulk head.\n\n[Pal](_URL_3_):The Pal was the biggest battleship of Marathas. The Pal had three masts perpendicular to the hull. They were made up of two pieces joined together just below the square sails. The stern of the Pal was square and had a spacious decorated deck. This was meant for the captain. The broadside of the Pal had four guns peeping through the portholes. \n\nSources:\n\n1. [Battles of the honorable East India Company: Making of the Raj - M.S Naravane](_URL_1_)\n\n2. [The Anglo-maratha campaigns before the conquest of india - Randolf G.S cooper](_URL_4_)"
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"https://books.google.co.in/books?id=bxsa3jtHoCEC&pg=PA99&dq=kanhoji+Angre+guns+boat&hl=en&sa=X&redir_esc=y#v=onepage&q=kanhoji%20Angre%20guns%20boat&f=false",
"http://www.istampgallery.com/wp-content/uploads/2016/05/1823-International-Fleet-Review-Galbat-India-Stamp-2001.jpg",
"http://www.indiandefencereview.com/wp-content/uploads/2017/08/Maratha-Ship-Pal.jpg",
"https://books.google.co.in/books?id=qweZWra_tbwC&pg=PA31&dq=shivaji+navy&hl=en&sa=X&redir_esc=y#v=onepage&q=shivaji%20navy&f=false"
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2ppwgh
|
when i'm tired, every now and then i will go through bouts of extreme drowsiness where i can't even keep my head up and eyes open, but after about 5-10 minutes i am awake again and completely fine. what are these cycles and how do they work?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2ppwgh/eli5when_im_tired_every_now_and_then_i_will_go/
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"Could be a bunch of things, but generally that's not normal. Could be blood sugar or blood pressure drops, narcolepsy, etc... Should see a doctor.\n\nIn my case, this would go on for an hour or two every couple days. I had a 3x2 inch tumor (what they call a \"schwannoma\", noncancerous) in my neck that was butted against my spine, putting a ton of pressure on surrounding nerves, and causing fatigue. Since I had it removed last month I no longer have these issues.",
"This can't be as abnormal as other posters are making it out to be. I experience the same problem sometimes if I did not get much rest the night before and I am doing something uninteresting. I try to think about how important it is that I stay awake in a meeting with my boss, for example, but sometimes I find it legitimately impossible to keep my eyes open, so I pinch myself ceaselessly until I wake up...",
"wait, this isn't normal? This happens on a regular basis to me, especially if I'm driving. I just get really, REALLY sleepy. If someone then starts talking to me, the drowsiness dissappears completely, almost right away. Shots of adrenaline, like from my tires hitting the rumble strips only jerks me up for about 30sec, then it's like it never happened (ie. back to feeling sleepy). I'd love an answer to why this happens, and if it's not actually a normal thing...",
"I know this feeling. You just battle it out, and then if you managed to stay awake, you're back to normal. \n\nI think its a mix of boredom, heat and exhaustion. If you're driving, sing along to your favorite songs, roll windows down or pull over and nap.",
"Like others have said, it could be a lot of things. I imagine a lot of people's fatigue is diet based. Usually after a meal there's a spike in blood sugar, depending on the meal and the composition of the meal. Meals high in sugar will jack up the blood sugar. You will be pretty energetic. The body will overcompensate and release a ton of insulin, plummeting the blood sugar. This will make you woozy and what not. The body will then try and correct the aggressive over correction, releasing glucagon, bringing the blood sugar back up to normal levels. ",
"It could be one of two things I'd say.\n\n1) Basic Rest and Activity Cycles.\n\nIn humans, the BRAC cycle seems to last 90-120 minutes. The first 75-100 minutes are a period of alertness and activity, with the last 15-20 minutes of the cycle being a period of marked somnolence, a dreamy (day-dreamy), drowsy state of consciousness. It is thought to be the inverse of the sleep cycles, where SWS and REM occur in similar 90 minute intervals.\n\nThe purpose of the BRAC cycle may have to do with brain electrolyte restoration. The rhythm has been found on EEG readings of the brain. It is also present in other animals. My personal experience suggests that these rhythms are very suggestible, sometimes unnoticeable if not absent at times. At other times, they can be like clockwork. It depends on what you're doing at the time, and your general state of health I'm sure.\n\n2) Microsleeps.\n\nIn states of marked sleep deprivation, humans can enter states of microsleep. These are very short episodes of sleep, lasting seconds on occasion. Whether or not they are beneficial or just side effects of sleep deprivation is unknown.\n\n",
"Jeez, people trying to spout claims of cancer and trying to prescribe drugs for this completely normal occurrence. This is normal, OP. Many people do not let themselves get tired enough to experience this, but those that have gone long stretches without sleep and had a period of minimal activity/movement/thought will know exactly what you're talking about.\n\nI don't have the correct terms off the top of my head, but I can assure you that there is nothing unusual about this.\n\nPart of you is trying to enter sleep, but you consciously decline the aggressive offer.",
"I have suffered something similar for as long as I can remember now. I could fall asleep in a cold hall curled up in a doorway in under 5 mins. I sleep for 10hrs without difficulty, love my bed and feel as though I could sleep for a 100 years. I constantly feel like im dragging my body around behind me. There are only two times in my life when i have felt 'full of beans' and full of energy. I regularly have to pull over for a sleep and this excessive tiredness makes me short tempered, miserable and has been a constant pain my entire life. Fucking sucks.",
"_URL_0_ \n \n\nIts called a micronap or microsleeping and it means that you're internally exhausted but you keep telling your brain to stay awake. So, during boring or times where your brain doesn't have to \"work hard\" or focus, it nods off for brief moments of time. (Because its tired and wants to sleep.) This is prone to happening while we are doing activities that we are very comfortable with and don't require a lot of movement. (Driving, Watching T.V., Games, etc. ) If this is happening to you, you need to caatch up on some back sleep. If not, you're gonna go into sleep debt. \n \n_URL_1_",
"Same thing happens to me but I also have narcolepsy",
"I used to have these symptoms. Turns out that I have sleep apnea. If you snore when sleeping you may have sleep apnea as well. After getting treatment for it, I no longer get bouts of drowsiness. You might get yourself checked out.",
"I'm sure it's correlated to brain wave activity. Think of a car's engine. You press on the accelerator, and when you reach a certain speed, you lower the pressure on the pedal. After a bit, especially in older engines, you'll lose speed and have to press the accelerator again. If you're not paying attention, you might accidentally go from 60mph down to 45 and not even notice. Your brain goes through the same struggle. A tired brain is analogous to an old engine. Like you, it tries to maintain the 60mph (beta frequency / alert work). If your brain is too tired to keep up, it slows down to 50 mph (alpha / calm, steady work and thought). If you stay in that relaxed state, you'll eventually hit 40mph (theta state /drowsiness and heavy-headedness), and from there go down to 15mph (delta waves / deep sleep). \nYour brain can't maintain 60mph beta alertness for too long either since it burns alot of gas (calories), but it's much less efficient if it didn't get the proper maintenance (sleep).",
"Are you overweight? I had similar symptoms - falling asleep at my desk, in meetings, etc. - and was diagnosed with Sleep Apnoea. That's fairly serious. I've since lost about 70 pounds and I sleep like a baby. I feel great every day now. You should probably talk to your doctor about this, rather than reddit.",
"Man, a lot of people are really eager to diagnose sleep disorders. \n\nFor the record, I don't think you are describing narcolepsy, sleep apnea, or anything like that. It sounds more like you are talking about a [liminal state](_URL_0_).\n\nMost of the time someone uses that term they are talking about life changing events or religious experiences. But it just means \"threshold\" and you sometimes hear it used to refer to the state between waking and sleeping.\n\nWhen we think of sleeping we tend to think of it as a very smooth process where our conscious minds just switch off. It doesn't quite work that way. It's more of a fuzzy cycling process between awake and asleep. For the first few minutes of sleep you bounce in and out of wakefulness. This happens every time. You just don't remember it. Why?\n\nEr, well, because it takes right around 30 minutes before short term memories can be converted into long term memories. If this process is disrupted, say by going to sleep, you just lose the memories. So that last memory you have before going to sleep was not the last moment you were conscious. That could have taken place up to half an hour after that point.\n\nBut, as I was saying, your brain and your body start settling into a more relaxed state. As this happens and you drift in and out of sleep, the periods of waking get shorter and shorter and the periods of sleeping get longer and longer.\n\nIt doesn't just end there, either. During the entire night you'll repeat this process over and over again. Around every 90 minutes or so in fact. You drift down into sleep from waking, bouncing in and out, and gradually settle into a deeper sleep. Then you start waking back up. You may actually even wake up briefly but, again, if it is less than 30 minutes you'll forget it. Back down you go. \n\nSo, back to your original question, what you are probably experiencing is that moment where your body is drifting to sleep. You may even have been asleep for a moment (someone else mentioned microsleeps and that's sort of right but most of the time someone talks about microsleep they are actually referring to when chronically exhausted people may fall asleep for a few seconds to a few minutes and wake up during a normal waking period). You were doing something that caused your brain to relax and you started the process of going to sleep. However, when you drifted back out you interrupted that cycle and forced your brain and body into a higher activity level. Since you are forcing yourself to be awake for long enough for the memories to transfer to long term memory, this time you recall your dozing off state. \n",
"Perhaps your body is saying you need sleep so it starts release melatonin, which makes you sleepy. When it realizes you are not going to be sleeping it stops releasing melatonin and you become less drowsy. Probably similar to how you are still sleepy when you first wake up. "
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2olx19
|
suitjacket, sportcoat, and blazer? which situation calls for which jacket?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2olx19/eli5_suitjacket_sportcoat_and_blazer_which/
|
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"Sport coats have patterns, unlike blazers, which are solid and have contrasting buttons. Suit jackets are smooth, have tonal buttons, and should never be worn with anything other than matching suit trousers.\n\n",
"Generally, suit for formal occasions, sport coat in winter and blazer with light slacks in spring or all year if you're a frat boy. ",
"suit jacket - this one will have matching pants so its best for business \nsportcoats - this one is also good for business, especially young prof. who want more bang for their buck (you can mix up the pants to create more looks). \nblazer - these tend to be just like sportcoats - but are navy in most cases. Also can be dressed up or down. \n\nTL;DR - sportcoat/blazer casual, and suit jacket less casual (tho not formal) ",
"Have you tried this question on the folks over at /r/malefashionadvice?",
"I was taught a little differently growing up about suits, sport coats, and blazers. \n\nAgreed with previous posters: suit coats should only be worn with matching suit pants. Generally worn with a collared button down shirt like an Oxford. Many variations of ties (long, bow, bolo) or no tie/ascot acceptable. Generally darker cool colors, greys, and blacks. \n\nSport coats are generally a different color than the slacks and are often worn for morning events or sporting events. It is acceptable to wear suit pants with a sport coat, but generally lighter color slacks are worn with sport coats. Never black. \n\nBlazers are often solid or a heavier weave pinstripe and are most commonly paired with more casual bottoms such as chinos, khakis or jeans. Blazers may have elbow patches and lapels of a different pattern/fabric. Blazers can be worn any time. \n\nFor true formal occasions, none of these are appropriate menswear: tuxedo only. \n\nThis info is probably no longer in style or correct and was handed down from my grandfather and great uncle when I was young. "
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
3yvmjh
|
why are so many large companies headquartered in minneapolis?
|
A handful of people have asked before about Silicon Valley, or NYC... Those places make sense, because of the reputation and availability to network. But nobody (at least, nobody I've asked about this) think "Oh, best place for corporate headquarters? Obviously Minnesota."
Even southern regional staples like Dairy Queen and Whataburger have headquarters there, and the latter even moved FROM Texas, where they were originally... Why would such southern companies choose to have headquarters in a region they dont even do business in?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3yvmjh/eli5_why_are_so_many_large_companies/
|
{
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"text": [
"Minneapolis has a well educated population, the standard amenities of a major city, is a hub for a major airlines, has a high livability index, and still maintains a relatively low cost of living compared to other major cities."
]
}
|
[] |
[] |
[
[]
] |
|
a88scv
|
why are b.c. (before christ) and a.c. (after christ) the reference points we have chosen to use for historical measure, as opposed to any other major historical event?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a88scv/eli5_why_are_bc_before_christ_and_ac_after_christ/
|
{
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"text": [
"Nowadays you often see “BCE” which stands for “Before the Common Era.” “BC/AC” was just a handy reference since many Western historians were/ are Christian. ",
"In the rest of the non-Christian world other systems are used. In fact entirely different calendars are used.\nHowever due to the outsized influence of Christian based European countries, much of the world also uses the European based calandar for commerce. ",
"Because Christians in Europe were the one who brought that system to much of the rest of the world when they explored and colonized and plundered it. Other local systems kept being used but the benefits of a more or less unified calendar that worked well and was sued by everyone else won out in the end.\n\nCurrent alternatives that are still used include the Hebrew calendar and the Islamic calendar which count from the beginning of the world (not really) and the birth of the prophet Mohamed respectively. They are not as appealing to wider use because the Hebrew calendar sort of has no fixed length and the Islamic calendar is lunar based which does not really work as well in latitudes were season are an important thing.\n\nSome places like North Korea have taken the Gregorian calendar (because it works) slapped traditional local names on the months and set the Year one to be based on the birth Kim Il-sung.\n\nMany places have a traditional calendar that only gets used for festivals and religious rites and use the normal Gregorian calendar for everything else."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
7h4fr1
|
if most psychopaths become psychopathic due to their childhood or a birth defect, why are most psychopaths male?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7h4fr1/eli5_if_most_psychopaths_become_psychopathic_due/
|
{
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"score": [
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"text": [
"Because contrary to what you might have been told, gender is not actually a social construct. Our brains are wired differently, and when they malfunction, they malfunction in different ways. Just like women are much more likely to suffer from unipolar depression, men are more likely to become psychopaths.",
"The debate about whether psychopaths are the result of nature vs nurture is still very much ongoing.\n\nIf and to the extent it is due to nature then the sex difference in psychopathy is likely to be due to the sexual dimorphism in the brain. Both women's and men's brains are mainly formed by estrogen, but the male estrogen is slightly different than the female estrogen because the estrogen in men is due to conversion of testosterone.\n\nIf and to the extent it is due to nurture then it is likely to be due to differences in how we raise boys vs girls. For example the amygdala - the center for emotions - is about 18% smaller for psychopaths. But newer research shows that the brain structure itself is due to the how we use the brain, especially in the formative years. The neural pathways we use as kids are the neural pathways that will dominate our brains as adults. Research shows that a young child dressed up as a boy receives less affection than a child dressed as a girl, and this will affect both personality development and brain structure.",
"1. first of all psychopathy isnt a term used in psychology anymore.\n2. What you may be referring to is anti social disorders\n3. I personally think its a nature thing\n4. Sexism affects men, believe it or not\n5. The role of a \"man\" in our society might be more financially lucrative, but there are many downsides\n6. Men and boys are expected to be emotionless. People tell 4 year old boys to stop crying and act like \"men\" that might mess a kid up in the future if it happens frequently\n7. This directly relates to the idea of \"an emotionless killer\" women are allowed to have emotions in our society, men are not\n8. This explains why most serial killers are men\n9. Fun fact, if a person is raised without social contact in their formative years, they cannot function properly later on and it cannot be fixed and many end up in homes for the mentally ill. This really shows how much environmental factors have an impact on young people, how suppressing boys emotions might have a large impact in their future selves",
"I don’t think most psychopaths are male, I think most psychopaths *we hear about* are male. Basically society encourages men to be violent. When you hear about psychopaths on the news it’s because they have done something horrible like murder, and since men are more prone to violence the psychopath in question will most likely be male. I’m sure the psychopathic women are out there— just not committing any terrible newsworthy crimes."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
7o96qt
|
What problems was fascism intended to solve?
|
Or to put it differently, what account did the fascists give of their policies? To clarify, I'm referring to the Italian political movement, not the Nazis; and their specific policies, the nuts-and-bolts of their administration, not their overarching goal of "make the nation strong". What problems did they identify in contemporary politics or economics, and how did they intend to fix them?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7o96qt/what_problems_was_fascism_intended_to_solve/
|
{
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"text": [
"Hi there. There's always room for more discussion (and follow-up questions) but you might be interested in [this older answer of mine](_URL_0_) about the prelude to Mussolini's rise. [This great answer](_URL_1_) by u/Klesk_vs_Xaero is also great overview of Italy's descent into dictatorship\n",
"Fascism aimed at fixing a score of new or recurring problems of the Italian nation – while some of those were considered defining traits of a general crisis of the liberal state, others were of course contingent, which is expected over a twenty years time span. For clarity I have chosen to begin with the pre-fascism issues that fascism attempted to find a fix for, starting right in the middle of the crisis of the liberal State.\n\nI also must say that in this Fascism wasn't really different from most governments, that sooner or later had to deal with “everything that doesn't work already” and often end up putting their hands to what was already working. I'll try to highlight those attempted fixes that had a firmer ideological root (or rather a stronger fascist tone), but the two fields mix together a lot.\n\nAlso; focusing on the weak points of the liberal state may give rise to the belief that Fascism was somehow unavoidable, a necessary consequence of the system's ailments. There is no reason to make such a statement; rather the judgement of the posterity over the liberal state has generally been more favourable than that of the contemporaries.\n\n\n & nbsp;\n\n\nThe liberal State existed, with ups and downs, from 1861 to 1922. Its trajectory was fraught with difficulties, such as the impressive backwardness of many of the Italian regions immediately after the unification, a systematic commercial deficit, wide differences in economical and social structure between north and south (average salaries varied over five times moving down from Liguria to Calabria). Despite some of these difficulties being almost insurmountable, there are good reasons to cast on the old liberal state a more indulgent look.\n\nThe view of the contemporaries was less rosy.\nThe failures of the liberal state to solve some of the more dramatic issues had led to a (some times legitimate, sometimes overly) critical view of the Government's actions; with a consistent thread of north-south polemics, that crossed the political field from “left to right” and grew to include socialists and Catholics as soon as they became relevant.\n\nBoth socialists and Catholics appealed to masses. The liberal establishment (those “left” and “right” that held control of the Nation from the Risorgimento years, until after WW2) did not. They really couldn't find a way how – and this went beyond the general difficulty for a traditional political group to survive in an age of expanded representation.\nThe liberals were – for better and worse – an aristocracy of administrators. They had grown and made their first political steps in an age when politics was the activity of a smaller minority, followed by the interest of a slightly larger minority. The man of government was not a leader, he did not inspire the people – he handled their goods (the Nation) for them, because they couldn't do so by themselves. Acknowledging this point was to them the key of the democratic process: the people understanding that they needed the politicians in the same way a sick man needs a physician, or a healthy one looks for someone to handle his finances.\n\nWith the influence of the masses on society growing, the reaction of the old liberals was either to try and turn into mass politicians (failing, as proved by the experience of A. Salandra, that largely appealed to the interventionist public during the “radiant days” that led to Italy's intervention) or to just wait and see, hoping the masses would prove themselves – well – good. When discussing the possibility of a socialist participation to his Government, Giovanni Giolitti argued that the program did not matter, that an agreement was possible with good natured men such as the socialist leader Filippo Turati. That the masses could refuse the agreement did not cross his mind; and not – this must be said – for malicious reasons; as Giolitti had been throughout his fifty years long political career one of the key proponents of expansion of suffrage and political participation. Just, his concept of political participation ended right there, where the people gave charge to the politicians. That a political system could not hold for long on such foundations was apparent – and various observers argued that was only Giolitti's mastery of the “parliamentary” institutions that held it together. Conservative liberal, Luigi Albertini, observed that *when it was the statesman that shaped the majority, that built it around himself from the most different corners, through the most tenuous pacts, grounded on every kind of transactions [...] and then he made the program, and more so established the supreme convenience not to bother with the program and bent his followers to every contradiction without even thinking of solving them [...] then the politician might do some good [...] but the corruption of the parliamentary system was getting deeper and deeper and leading to grave danger in the future. At that point it was no longer a majority government, but a personal government and the function of oversight, to which the Parliament was needed, even more than for the people's representation, was substantially non existent.*\n\n\nStill, if we look at general economical-social indicators, the Giolitti era (1901-1913) appears to have been one of remarkable success (with the most favourable estimates giving a yearly rise in industrial production over 7 points). It was also that period when the criticism or downright opposition to the liberal system became more “dramatic”, to the point of gaining the denomination of *anti-giolittismo*, that was common occurrence already at the time [and has been discussed thoroughly by E. Gentile in various works – such as *Le origini dell'ideologia fascista* and *Il mito dello stato nuovo*]. That the growth of a fascist ideology owes much to the concept, imported from Sorel and Bergson, of a “political myth” - which essentially is an irrational theme the masses could rally behind, without requiring a level of understanding that is only possible for an individual – is a key element of Gentile's analysis. And it is rewarding to look at fascism almost in musical terms, as a composition of themes, either pre-existent or new. But, first, back to reality.\n\nGiolitti's Ministry followed a tradition of extra-parliamentary parliamentarism; a praxis where the Parliament and governative action were established and sanctioned outside and independently from the Chambers. The Parliament became thus ancillary to the legislative function, that should have been its primary reason of existence. This situation was broadly acknowledged by the liberals, even those who were part of the Government groups. In the last Chamber session of 1917, liberal Giuseppe Sanarelli argued for a reform of the Chamber's regulations pointing out that the Parliament regulations *were outdated already before of the war* as they contained no preventive measure *against the undeniable, progressive disrepute of the parliamentary institutions*. *The Country had often bemoaned [the Parliament's] waste of time and the poor performance of the parliamentary engine* whereas, *even the most valuable and esteemed* of its members have been accused of *limiting their action to purely verbal manifestations*. It was therefore necessary to devise a way to *translate into practice and effective value the good will and special abilities of the Parliament members*.\n\nThe reforms *would have re-established the value of the Parliament, allowing it to work as it is its right and duty*. Furthermore these institutions would have *restrained, corrected and channelled the impetuous stream of bureaucratic imperialism*; as the Parliament had been reduced to nothing more than *the highest advisory committee for the bureaucracy* to the point where the Ministries themselves had became *delegates of the majority to the Administration*. \n\n*The Parliament still loved that Idea […] of personal and individual freedom of the government* but in fact *lack of decision power as well as excess of decision power* were not *acts of individual choice* but *chronic ailments […] of every democratic system*.\n\nAccording to Sanarelli the state of things *was responding to neither the letter nor the spirit of the constitutional chart, which established […] the existence of a legislative power, not just distinct, but superior to the executive one*. On practical ground in fact, the situation was much different as the Parliament was *content with academical dissertations over the balance [under the Statute, approval of budget was a key element of influence of the Chamber on the governments action], without ever promoting modifications or revisions* or *abstract discussions over law projects devised by the bureaucracy and promoted by the ministries*.\n\nSuch a situation had become more apparent during the war through *the relations between the organisms of military power, those of political power and those of parliamentary power*. As Giuseppe Bevione had denounced, *as far as military action was concerned, the Supreme Command had enacted an undeniable dictatorship, updating the Government only summarily* and *established a State within the State, a Government above the Government*. At the same time *relations between the Government and the Chamber had been just as week and sporadic*; *the work of the Chamber was reduced to either confirm or deny confidence to the Ministry*."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/49g1wb/what_led_to_the_rise_of_mussolini_how_did_he/d0s5dpm/",
"https://www.reddit.com/r/AskHistorians/comments/4a7b0f/mussolini_was_made_prime_minister_in_1922_at_what/d0y4koe/"
],
[]
] |
|
4ca43l
|
Why is it that the inside of fresh water pipes that feed houses don't need regular cleaning?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4ca43l/why_is_it_that_the_inside_of_fresh_water_pipes/
|
{
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2,
2,
14,
2
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"text": [
"They need. If you use a pipe system for 20+ years there is gonna be a lot of build up. Most of the time its not necessery bad.\nThe thing is nobody thinks about it. \n\nIn germany the situation is as the following: the main pipes up until to the house are the responsibility of the city.\nEverything after that is the one of the owner. Industrial Buildings have to get checked more often, private ones not as often.\n\nNot quite sure about the intervals though I guess it was something between 2 - 5 years.\n\nHow it is handled in America? No idea.",
"Well, galvanized pipes can get a buildup of calcium and magnesium from electrolytic reduction of the ions. And I suppose you might be able to get some mineral build up from very hard water, but generally the more or less constant flow of water prevents that.\nOtherwise, what would build up that would result in it needing cleaning?\nWith the lack of bacteria, and the movement of water, there should not be any real thing in the pipes to build up--other than the a fore mentioned calcium and magnesium.",
"They do need regular service, but not many people bother. Usually if you have more than a few faucets running at once the flow will clean them out. \n\nI have opened up a pipe to a shower in the basement that only runs every once in a while and found sediment closing off more than half the pipe. \n\nWhen the water stops, then you call a plumber to replace them. You're not going to find anyone willing to swab your household pipes. You could top your water main, drain your pipes and start them again. That will mix up any sediment in them and let you know if there's an issue. ",
"They are designed so that there are no blind ends or dead angles, where bacteria or deposit could build up. An example of how this failed was a case where the cooling system of a power plant had a blind end in their piping. *Legionella* bacteria found the place, made a little colony and then spread around the area with the mist from the cooling tower, infecting many people.\n\nSecond, tap water is chlorinated, even if it's pure at the source, exactly in order to avoid bacterial buildup. Small concentrations of chlorine are good enough to prevent growth, even if they can't be used for desinfection as such. A little ammonia is added, because when chlorinated, it forms more persistent nitrogen chlorides that retain the active chlorine in the water better than plain chlorine, which gives only a chlorine solution. If there's a breach of the integrity of the piping or a problem at the source, a \"shock chlorination\" is done to actually desinfect the pipes.\n\nEven so, buildup is a thing. Fortunately, much of it is inorganic, like calcium and iron salts. Because it's washed continuously with water, it attains a pseudo-steady state where it releases little material into the water. However, over time, it can build up to such a point that it affects the water pressure.",
"To add what everyone else is saying, in the United States, many water pipes are made from either copper or a plastic called PEX. Copper has shown remarkable antibacterial characteristics while PEX doesn't support bacterial growth"
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
a9k4bp
|
what makes our ears ‘clog’ in high altitudes and what makes them pop by yawning?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a9k4bp/eli5_what_makes_our_ears_clog_in_high_altitudes/
|
{
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"Im pretty sure when there’s low air pressure it messes around with how your inner ear functions and yawning sorta stretches it making it “pop”.",
"Air in your middle ear is at a higher pressure than the surrounding air; popping is allowing that air to equilibrate with surrounding air (via a connection to the throat).",
"When you go from a lower altitude to a higher altitude, the ambient air pressure decreases. Because the air inside of your eardrum is semi-trapped (you can clear them) it expands as you go higher and puts pressure on the eardrum. When you yawn/chew/etc it helps open up the eustachian tubes that go from the backside of your eardrum to your throat and equalize the pressure.\n\nSource: I have 2200+ skydives and had to clear my ears a lot. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
3ca9h5
|
Imagine an empty room with no windows/doors or any point of entry and escape with just a light bulb inside and a light switch outside. What will happen to light if I open the light for 10 seconds and turn the switch off? Will the brightness remains or will fade? Why?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3ca9h5/imagine_an_empty_room_with_no_windowsdoors_or_any/
|
{
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"cstnyol",
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3
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"The light will fade almost instantly. As the light strikes the wall, part of it is reflected and part of it is absorbed. The reflected light will bounce away from the wall until it hits another wall (or floor/ceiling) and then again, part of it is absorbed and part reflected. With every bounce the intensity of the remaining light decreases. And with the speed of light being very high compared to the size of an average room, there are many bounces in a short period.\n\nConsider the following, we have a room with 10 meters between two walls and a light source at one end, shining a straight beam in the direction of the other wall. All walls are made of very high quality mirrors that reflect 99% of the incoming light. How much is left of a light pulse after 1 milisecond?\n\nIn 1 milisecond, light travels 300,000 meter, so that's 30,000 bounces. Each bounce reduces the intensity by 1%, so that means we have a fraction of 0.99^30,000 remaining: Approximately 10^-131. So after 1 milisecond, a thousandth of a second, any light will be completely gone. And that is in the scenario with very high quality mirrors. With regular walls only reflecting a small part of the incoming light, the intensity will become too small to detect in microseconds or even less. ",
"The visible light will almost instantly, as explained by /u/rannasha, but the energy will remain within such a closed system in the form of heat. If it were a 60 Watt light bulb that you were lighting, then it would instead act more as a 60 Watt heater. "
]
}
|
[] |
[] |
[
[],
[]
] |
||
8y3rcf
|
why are surgical gowns, masks, and gloves green or blue?
|
Wouldn't white be a better color since doctors usually wear a white coat and white provides better contrast with red color of blood.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8y3rcf/eli5_why_are_surgical_gowns_masks_and_gloves/
|
{
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"e27w05a",
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2
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"text": [
"They used to be white. There's a sort of 'surgeon legend' about the green being used because it was easier to see in a surgical field (brightly lit + whites = too bright). But then also that green/blue is actually opposite red and makes it easier to see blood. But I think it's kind of one of those \"was written down somewhere once\" and became cannon type of things. Whether it's true or not. ",
"I was always told it was so you wouldn't notice the reverse color image that's been burned into your retinas after staring at a brightly lit, blood red surgical field for hours when you glance away from the field. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
32eegb
|
In medieval times, how long could a knight physically fight in a battle? The swords were heavy, the armor was heavy. Nutrition was poor. Could they last more than 30 minutes?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/32eegb/in_medieval_times_how_long_could_a_knight/
|
{
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"cqagl68",
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"text": [
"This doesn't directly answer the question, but I think you may be overestimating the weight carried/worn by a knight.\n\nThe average sword weighed somewhere around 3lbs, an M16 with full ammo weighs about 9lbs.\n\nA suit of full-plate would generally weigh less than 60lbs (sometimes significantly less), such armor was also custom fitted and designed to be relatively easy to wear with little strain. A full set of modern combat gear tops 60lbs, and is \"one-size fits most\".",
"\"Medieval times' is to big a timeframe to answer really. In early medieval period 'knights' would be nobility. While knowledge of nutrition was poor most nobility had a strong diet of meat. While poor in vitamins it's pretty great for getting muscle. They also had less plate in this time and relied more on mail and gambersons. For mail I want to point out it's worn on the hips with a belt and not hanging from the shoulders. That really helps with the strain. \n\nIn the later period most 'knights' were in fact man at arms, professional warriors not of noble birth. While plate was dominant at that time plate is form fitted to the wearer. It's not heavier then what a modern infantry man wears. \n\n > \"In Afghanistan, soldiers routinely carry loads of 130 to 150 pounds for three-day missions, said Jim Stone, acting director of the soldier requirements division at the Army Infantry Center at Fort Benning, Ga. In Iraq, where patrols are more likely to use vehicles, loads range from 60 to nearly 100 pounds, he said.\"\n\n_URL_0_\nThat's double a full set of plate. Of course you still got a weapon to wield. But most weapons are pretty light, less then a modern rifle and perfectly balanced. A well balanced weapon isn't exhausting to wield. \n\nHowever full plate wearers did have one problem to overcome, heat. Wearing undercloths, a gamberson, some mail and plate was a pretty hot combination so I see over-heating being more of a problem then weight. \n\nAs for cleaving, you don't cleave with a sword. Against a user in plate you'll be stabbing with thin blades or crushing with a mace. For a mace you'll be keeping momentum and not ending your swing while the stabbing will be quick. Getting knocked down was a death sentence, beside that getting up wasn't that hard. Just laying there opened so many openings for a stab with a dagger.\n\nWhile yes wielding a melee weapon is more tiring on the arms I doubt combat was that much more physically demanding back then for a 'knight'. Modern soldiers carry around lots of gear, a M249 weights a lot, a WW2 browning MG even more. Preferably a duel/fight lasts as little moves as possible, you don't keep hitting the other guy till one drops like a boxing match. But I can't give you an exact timeframe.\n\nThis might interest you, while not being a direct answer it does go on about the weight of armor and the comfort of wearing it.\n_URL_1_"
]
}
|
[] |
[] |
[
[],
[
"http://www.washingtonpost.com/wp-dyn/content/article/2009/01/31/AR2009013101717.html",
"http://www.reddit.com/r/AskHistorians/comments/275iz3/in_shows_like_game_of_thrones_characters_wear/"
]
] |
||
5ol96w
|
If I were to travel ten light years going the speed of light, would it seem like an instant to me, but ten years for an outside observer?
|
I've recently been obsessed with anything discussing Einstein's relativity equations. This concept is by far one of the most intriguing. That is, if I am understanding it correctly. I'm posting this just for clarification if it is true that going any distance at the speed of light is instantaneous to the object traveling that speed. But to an outside observer, it took ten years for that object to reach them from ten light years away.
|
askscience
|
https://www.reddit.com/r/askscience/comments/5ol96w/if_i_were_to_travel_ten_light_years_going_the/
|
{
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"text": [
"You *cannot* travel *at* the speed of light, so this question becomes pseudo-scientific.\n\nBut let's say you were travelling *really* close to the speed of light. Like *really, really* close. Like 99.999...999% with a billion, billion 9s after the decimal place. Then yes, what you say is correct. To you, the journey would be nearly instantaneous. To me, standing on the Earth, the journey took you a little more than ten years (assuming you travelled 10 light-years). \n\nBut, if I could measure your clock during your journey, I would notice that your clock has come to a near standstill. You and I would both agree that, to you, the journey was nearly instantaneous.",
"This question has already been answered, but I'll try to answer it in a slightly different way.\n\nImagine that all objects, including yourself, have a certain amount of energy. Objects can use this energy for two things: move through space and move through time. The faster you move through space, the less energy there is left to move through time. Once you travel at the speed of light, there is no more energy to move through time. Time is no longer a thing when you're traveling at the speed of light.\n\nLet's just go through the question you asked piece by piece. A light year is the distance traveled by light in one year. When will this year pass from your point of view? It doesn't. It's undefined. This means that for your point of view, it's simply not a thing. You just can't travel at the speed of light. This is because you have a mass. An outside observer would experience time, so let's take the perspective of the outside observer now. When you travel 10 light years from the outside observer's perspective, it will indeed take 10 years. This is common sense, it's just the definition of a light year. As soon as your perspective is introduced though, everything stops working because time is no longer a thing.\n\nThis whole thing about energy being used to move through space and time is not exactly correct, but it's not far away from the truth either. It's not energy that we're talking about here. But the basic principle is the same. Light under this sort of analogy can travel at the speed of light because it doesn't have mass. The energy used to move is zero. Kimetic energy is (m*v^2 )/2, so any velocity requires 0 energy. Again, this is not the way things actually are. They're even more interesting in reality, but it's a good representation."
]
}
|
[] |
[] |
[
[],
[]
] |
|
7mgcxp
|
How does pilot wave theory account for quantum fluctuations?
|
From what I understand, pilot wave theory assumes the uncertainty principle to be a flaw in measurement instead of a fundamental "property" of particles. (correct me if I am wrong)
Quantum fluctuations are the result of the uncertainty principle, these fluctuations can be observed and modeled.
How does pilot wave theory account for these quantum fluctuations?
Kind regards,
Dagl
|
askscience
|
https://www.reddit.com/r/askscience/comments/7mgcxp/how_does_pilot_wave_theory_account_for_quantum/
|
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"The guided particle doesn't move through space, it moves through the space of possible positions of all particles, which instead of just 3 dimensions has 3N dimensions, where N is the number of particles. The positions of particles in a measurement device is included in this, so the question of what kinds of measurements are possible is also determined by the motions of the guided particle, which is in turn determined by the pilot wave. \n\nThe pilot wave is just the total wavefunction of all the particles and is *unaffected* by the guided particle, so all the usual aspects of quantum mechanics are already there, including the uncertainty principle. The only role of the guided particle is to bounce around like a ball in a pachinko machine, with the odds of outcomes determined by the pilot wave but only one of them realized by the path of the guided particle. So ultimately the probability of measuring a particle's position or momentum in a given place is determined by the wavefunction, and the statistics of those measurement results must obey the uncertainty principle. ",
"In pilot wave theory the whole physics is determined by the pilot wave, which has all the features the regular wave functions have. The particles guided by the waves just tell you which result of a measurement you are supposed to interpret as real (the one with a particle in it, basically)."
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[],
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|
bud7iq
|
AskScience AMA Series: I am Jamil Zaki, professor of psychology at Stanford University and director of the Stanford Social Neuroscience Lab. I wrote a book called The War for Kindness, which shares stories and research about how to fight for empathy even when it feels impossible to some days. AMA!
|
Hi Reddit! I’m Jamil Zaki, a professor of psychology at Stanford University and head of the [Stanford Social Neuroscience Lab](_URL_3_). My first book, called [The War for Kindness](_URL_2_), comes out next week!
For the last fifteen years, I’ve studied empathy—people’s ability to share, think about, and care about each other’s experiences. My team investigates everything from the brain mechanisms that allow us to accurately understand what others feel, to the relationship between empathy and kindness, to the ways helping others de-stresses us.
While examining empathy as a scientist, I also noticed that it seems to be in short supply. Isolation and tribalism are rampant. We struggle to understand people who aren't like us, but find it easy to hate them. In fact, studies show that we are less caring than we were even thirty years ago.
I wrote The War for Kindness to explore and explain why it can feel so difficult to connect with people amidst modern barriers. A key point of the book is that empathy is less like a trait, and more like a skill, something we can build and strengthen even in the face of those barriers. It’s not always easy to grow our empathy, but I think it’s crucial we try.
If you’re interested, you can pre-order a copy of the book here: _URL_1_
You can [see](_URL_0_) I'll be ready for your questions at 9AM Pacific/Noon Eastern (16 UT), AMA! Here to answer any and all of your questions about kindness, caring, goodness, badness, and horse-sized ducks (VERY strong opinions).
Also, today is my mom’s birthday. Happy birthday, mom!!
EDIT: Thank you for your stellar questions! I have to run for a few hours but will come back later today and try to answer more.
|
askscience
|
https://www.reddit.com/r/askscience/comments/bud7iq/askscience_ama_series_i_am_jamil_zaki_professor/
|
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"Excited to read your book! I work in early years education in conflict/post-conflict zones and am constantly looking for ways to include empathy-building in the classroom.\n\nWhat do you think it will take for educational policy to reflect the need for empathy in our curricula?",
"Which country do you think must be reaching highest on empathy scale, and why ?",
"Are there empathy building exercises that have tangible impact in practical life ? Do such exercises really work or are just scoffed off by adult participants ?",
"How far are we from empathy enhancing technology? And is the research done at your lab conducive to such tech?",
"Three fast ones for you:\n\n1. How does one measure empathy from year to year etc.?\n2. Would you define empathy as somewhat of a muscle?\n3. What do you think is the reasoning for the decline?",
"Do you feel that Sam Harris’ work on free will and the lack of it promotes empathy within the society or does the religious side have a better argument for empathy?",
"What scale did you use to measure empathy, and how sure are you that empathy is what was really being measured?",
"How does empathy fatigue play into your research? Being that we're so connected with the world and other peoples lives, how do we stay empathic without burnout?",
"What are your thoughts on the emerging field of \"neuropsychoanalysis\"?",
"I completely agree with you that empathy is in short supply. That said, how does empathy integrate with game theory, specifically bad-faith participantsbir \"defectors\". It seems there is a fairly consistent trend towards authoritarianism globally. Is empathy a useful tool to address this?",
"Thank you for taking the time for do this AMA professor. My main questions are about external influences on the decline in global empathy. \n\n- Is empathy declining more rapidly in individualistic countries like the US or in collectivist countries like Japan? \n\n- Do you think people are becoming too quick to attribute things together which results in quick assumptions of a person, that can lead to a decline of empathy? \n\n- This sort of leads to the idea of the whole current #cancelled movement where actors/celebrities are called out for behaviour by accusers. One example is the Kevin Hart and Oscars fiasco. What do you think about that ordeal? \n\nThank you for this opportunity to answer some questions :)",
"What does it mean for your research and efforts if the \"empathy defect\" isn't causing the problems that appear to be linked to a lack of empathy? How conclusive are these studies that claim empathy has been declining? How do you ensure that you aren't just aiming at targets that have materialized from sociological hand waving?",
"Hi Dr Zaki. Can you tell us what an “optimal” level of empathy is, how to build empathy in ourselves, and also whether the concept of being “overly empathetic” exists? Thanks!",
"How can someone become devoid of empathy on purpose?",
"Comparing massive urban areas, to smaller urban areas, to rural areas: how does population density affect empathy and, if we can know pertinent information about this, do we have a duty to plan our population density accordingly to maximize empathy?",
"You seem to be the antagonist to Paul Bloom. How would you argue against his position? Or do you just have different definitions of the word empathy? Sometimes he says \"empathy\" but all I hear is \"emotionally irrational\".",
"Thanks so much. I have two questions. \n1. How do you recommend finding a balance between giving empathy and honoring your own pain? I know they're not exactly in conflict but many of the conversations I see devolve into people comparing someone else's pain to their own instead of each connecting with the other. \n\n\n2. How can we build empathy in professional settings where it is required but hard maintain? I know many healthcare professionals go into the field specifically for empathic reasons but get burned out. Alternatively, many of those in the criminal justice system (lawyers, prison guards, law enforcement) are not deaf to empathy but it is not a focus of the job and many would claim it is antithetical to the jobs purpose.",
"What sort of interesting conversations have you had with your colleague Robert Sapolsky on the overlaps between your research and his work on conflict and stress? \n\nWould you say that primate communities are more or less empathetic than human communities? Are our instincts supporting empathy or do we develop empathy in spite of our instincts?",
"In your studies, have you seen a relationship between a lack of empathy and the feeling of isolation/loneliness? I wonder if the more disconnected people feel in their communities, the less likely they are to relate to those around them. Thank you!",
"Hi Dr. Zaki! Can you tell us why sometimes people who can empathise with a community living in distress, in a far away place, find it hard to empathise with people close to them?",
"While it can be easy to empathize with people we can agree with, it can be very hard to empathize with people we deeply disagree with, such as our political opponents. How do you think we can increase empathy for people who have dramatically different political beliefs? Can empathy be used to decrease political polarization in our hyper-polarized times?",
"How do people naturally end up with empathy, how do they learn to recognize these things without being told?",
"Is empathy \"activated\" through experience with people of various backgrounds or is empathy better off being taught to someone (as opposed to experience)? Or is it more complex than that?",
"I believe that the fact empathy is in short supply, and that isolation and tribalism are rampant, are symptoms of a bigger problem. Parents today, \"want to raise their kids to have it better than they did.\" However, I don't think this parenting style is working. Discipline, hard work, and being lead by example, are all important life lessons that go missing under the new style of parenting. When you take away these life lessons, kids get conditioned the wrong way -- and you're pointing out the results. What are your thoughts on this?",
"Why do you think people nowadays are less emphatic than before? How does the internet affect this? Do you think that when we encounter the same issue too many times, we are being less sensitive about it, unless we got to experience them first hand",
"What is your view on psychopaths and their lack of empathy? Do you think they can be taught or programmed to feel a level of empathy for others? Especially regarding the difference between hot and cold empathy.",
"What are your thoughts on Dr. Fritz Breithaupt's assertions that some of our current problems with terrorism and incels may actually stem from excessive empathy rather than a deficit and empathy, but excessive empathy in favor only of one's own group, to the exclusion of empathy for others? He has talked about this and some of his recent books and in a recent NPR interview.",
"What about someone who had too much empathy?\nI've been told that. At first I thought they were crazy, but now I've started to notice that I do try to think of and please everyone, to the point I often forget myself.\nI enjoy understanding unique positions, and unique people, and I really enjoy seeing people happy. But what do I do if it has taken over my own identity?",
"What do you think we can do to bridge the political divide here in America before we devolve into a civil war?",
"Why is it so crucial that we practice empathy? And in what ways, if any, (scientific or otherwise) do you think that being empathetic leads to personal gain?",
"Thank you so much for doing this AMA! I’m a huge fan of your work.\n\nHas there ever been a moment in your life where you felt a strong sense of Empathy for an aspiring researcher, because they were making a similar mistake you might have made?\n\nWhat can the average person do in their life to increase their Empathy? Alternatively, what small things can people do to help someone else change their Empathy towards others?\n\nYou probably get this question a lot (I’m sorry): What advice would you give young people who are aspiring to have careers in psychology research?\n\nThank you so much!! :)",
"First off, thank you so much for doing this important work. I've witness a dramatic decline in empathy among those I know, both online and IRL, and people in general, and I've become extremely despondent about it all.\n\nWhenever I've attempted to discuss this general lack of empathy, especially as it concerns tribalism and \"the Other\", I find that my friends and acquaintances immediately become defensive. They typically immediately fire back that \"Tribalism only exists among \\[the other side - usually \"the Right\" from their perspective\\]\", and have told me if I think tribalism exists anywhere else, I'm just believing \"their\" right-wing / racist / nationalist propaganda. This is clearly a) false, and b) part of the exact problem I've described, but they refuse to see the forest for the trees.\n\nHow can a layperson like myself push back against these stereotypes and change minds with legit information? Can you recommend any credible and (relatively) easy-to-digest published material to help regular people overcome the echo chambers and see that this is a problem affecting all of us?",
"Thanks for doing this AMA. \n\nMy friend asks, is there a relationship between emotion regulation and empathy. If there is, is emotional regulation capable of enhancing or diminishing empathy?",
"Would you advocate for teaching empathy skills to criminals? In what way do you think this should be implemented?\n\nThank you for your time!",
"What's the most important advice you can give an early-career cognitive neuroscientists trying his best to improve science and increase our body of knowledge? Thank you!",
"Is there some study which describes the relation between empathy and religiousness? i.e are religious people more/less likely to empathize as compared to non-religious people.",
"What has been the recent paradigm shifts with regards to advances in neurosciences and its effects on psychology as a field? Has the \"hard science\" of biochemistry been connected to the \"softer ones\"?",
"Which religion had the highest levels of empathy? My money would be on Buddhism, but I'm curious to see if this would be correct.",
"A lot of my questions you've already answered but I would like to say that I really enjoyed this post and your insight. I am currently studying for my bachelor's in psychology and addiction counseling. Empathy building skills has been a huge part. I certainly believe there has been a large decline of general empathy in the world, its discouraging at times.",
"How do we help the unempathetic want to change? For example, schools are rife with bullies and ‘mean girl cliques’. What would motivate those young people to feel empathy for the less fortunate/popular/athletic and cease their hurtful behavior?",
"Is there evidence that high levels of empathy has become more of a negative trait than a positive one? I.e empathetic people being more stressed by the news, experience more suffering, etc?",
"Kindness is great but empathy and kindness are such vague concepts and it's very individualistic. It doesn't work on systemic problems or collectively like feminism or socialism. Did you ever consider these concerns to your work ? I guess we should all be empathy warriors in the war for kindness.",
"What line of work would be somewhat profitable for someone who's very empathetic? I don't mean caregiving and similar. I want to do good for my fellow humans, but also make a decent buck along the way.",
"Does killing your enemy with kindness really work?",
"Are there people with no empathy but not actual *sociopaths* if so what would be the signs of that?",
"Is there a thing like being overempathic? Sometimes to de-stress myself i imagine myself doing random acts of kindness to people. For instance talking a depressed individual away from suicidal thoughts or sacrificing myself to save a little girl. I also feel dissatisfied while enjoying things for myself (excluding things that can only be enjoyed by a person) say like eating a snack. I feel if i hadn't shared it i really haven't eaten it (although the hunger does go). I always sacrifice myself when an opportunity can be given to someone else. I try to relate to people so much either in fiction or real-life just to understand how they feel. An ordinary commute will see me observe little details of persons for that. I'm confused because at times i know it shouldnt concern me and at times i feel i might be unfair to myself.",
"Are religious people more likely to be less empathetic than the average person?",
"Thank you for doing this AMA. I'm highly interested in this subject, though I am just now beginning to comprehend it and have never really read about it in depth. I'll surely listen to your book. That said, and this is a really silly question, why are there two versions of your book on Audible, both equal in length and almost equal in price?",
"How does apathy and empathy work together? Can they coexist?",
"What's your take on the abuse of empathy by social media for monetary gains? You mention burnout due to bad news but most bad news are intentionally exaggerated because outrage gives more views, to the point that some people have a worldview completely manufactured by bogus information, and I'm taking the whole ideological spectrum here.",
"Happy birthday to Jamil’s mom!",
"Hi Dr. Zaki! I attended SANS this year and really loved your presentation (congrats on the award, by the way). I don't really have a question (outside of, uh, can I post-doc in your lab in a couple years??), just wanted to say hi and I'll be purchasing your book! Best of luck with your future endeavors!",
"Of the people I know with Aspergers, some tend to exhibit extreme empathy while others struggle with an extreme lack of empathy. \nIs it common that people with Aspergers tend to fall into polar extremes?",
"I work in an industry that we are taught empathy in a way, at least we are asked to think about it. From personal experience and speaking to my colleagues, very hard to emphasis when the person we are trying to be empathetic with is unknown to us, when there wast personal experience in anything we need to involve empathy. We need a strong personal will to be able scratch a surface of empathy, so if someone is genuinely emphasising with you, don’t take it for granted.",
"Can you describe your understanding of the closely related concept of boundaries, specifically healthy boundaries, how they are determined empirically, and how they correlate with empathic function? Can you give an empirically based definition for empathy?\n\nAlso can you discuss how unhealthy empathy (codependence) works in contrast with healthy empathy, and it's relation to pathological narcissism vs. healthy narcissism? Please give as much/many empirical definitions and standards for your answer as possible.",
"I haven't read any comments yet, I just want to say that I love the idea of this book and will be buying it.\nAs an RBT and (former) student of Psychology, I believe empathy and kindness are the most important skills to share with others on a daily basis",
"I've struggled since having graduated with my masters to make sense of my experience with my supervisors. It seems to be a generally unaddressed problem but to most who have gone to grad school it seems most have some negative experiences (work looking at depression in grad students seems to support this). After reading your AMA part of it clicked in me. I didn't feel like my supervisor really related or empathized, which struck me as a bit strange since he was once upon a time a grad student. I don't think this is isolated to this specific situation (though maybe it's more precarious because the rest of your future can heavily depend on a supervisor because of recommendation letters, etc) but is probably true for any situation having similar power dynamics. I was wondering if you had any insight into how power dynamics and empathy affect one another?\n\n\nThann you for the very insightful AMA.",
"Fantastic! I can’t wait to read this. I did spend some time on the farm, myself. I have complex ptsd and I’ve been studying rapists and the brain, to try and require my brain. Do you have any suggestions on other books I should read to help me with my studies and help with my ptsd? I’m currently finishing a book by Vander kolk, ‘Body keeps the score. I have been stuck at home for a few years now and couldn’t finish school, one day I will. Do you need any scut monkeys to volunteer?\n\nEdit: rewire my brain*",
"Do you think your research into empathy building can be used to help rehabilitate those convicted of sex crimes (or other violent crimes)? I remember reading that a major personality component behind rapists and murders was a profound lack of empathy for their victims. Would you have any advice on how a rehabilitative organization would implement that?\n\nHappy bday to your mom!!",
"I try to empathize with everyone, but this becomes controversial when empathy is directed towards terrible criminals or people who have done horrible things. In fact, in these cases we as a society have decided that these people do not deserve empathy. Even the concept of mildly defending someone who has done something terrible is looked down upon. What are your thoughts on this situation? Is the restriction of our empathetic capabilities when it comes to the law a good thing?",
"Why do psychologists tend to be liberal? Aren’t Christians (and other conservatives as well) also drawn to the prospect of helping people suffering from mental issues?",
"Hi Jamil! Personally I believe in the fact that one of the biggest things we as humans have lost due to our rapid and dynamic lifestyle resulting from an exponential progress as a species over the past century is empathy.\n\nSo my question to you is, which of the major developments or milestones achieved by us according to you has contributed to it the most.\n\nAlso, to what extent do you think this lack of empathy in humans are being exploited by people like politicians in a political climate which seems dangerously divisive, and can it be stopped? Or is it too late?",
"Hello Dr. Zaki, I am so excited to buy your book! Please tell me, how do you nurture empathy for yourself?",
"1. Do people with less empathy tend to be more financially successful than people with high empathy?\n2. How do empathy towards people and environmentally friendly behaviour correlate?\n3. Are people with a lower amount of empathy correlated to a certain tendency towards a political spectrum (left/right)?",
"Reading Lakoff and putting things in a political perspective, he might say that someone shopping and seeing a homeless person might make themselves feel better by reasoning that the person perhaps made some bad choices and the wealth ramp is there to teach us to do the right things. A war for kindness will have to break that linguistic frame. How?",
"Your name translates to \"Pretty Smart\" and that's just some good RNG",
"How would you suggest breeding empathy in couples? Learning to be there for each other or detect emotional need or pain?",
"What effect does social media have on young people's ability to socially connect, and their ability to develop empathy and kindness? Also, what did you think of Matthew Lieberman's book Social: Why Our Brains are Wired to Connect?",
"Wow! Now I need to read your book. I’m an ER Nurse and I would say I practice empathy deeply every day I work. I think it is what makes a good nurse, great. I’ve considered researching it further for a possible PhD, put simply I think nursing is the practice/job of empathy. Thanks for giving me more to consider. I look forward to reading your book. Have you spoken to/worked with any nurses?",
"Does it go over empathy and its role in social justice?",
"Hi Jamil, your work is certainly interesting and appreciated. Well done.\n\nLiving in Christchurch, New Zealand we have just witnessed sad events which have really shocked\n\nand asked us to reassess how empathetic we really are. Jacinda Ardern- prime minister, has been noble in tasking everyone to rethink\n\nour empathy and become more skillful in applying it.\n\nAll the best\n\nA.",
"Hey!\nWhat an interesting book. I may be too late but here are a few questions:\n\nIs empathy self-reported? \n\nDo you find that people over or underestimate their level of empathy?\n\nIs there a danger of being too empathetic? This is mostly related to the term “empaths” (not sure if this is recognized in the scientific community). Either way— I would love to hear your thoughts on it. \n\nThanks for doing this!",
"When talking about children specifically the first 3 years of life. What interactions with children would you say build empathy? Is it crucial for them to begin early, would it effect the way they build relationships if they don't? I ask because my 18 month old seems highly unbothered with any kind of empathy (someone is crying, or someone gets hurt) when I watch him in these situations it seems he realizes what's going on and removes himself from the room altogether if he can. I was told it may be a sign of autism but docs say they don't believe he is autistic because he shows no other signs... should I worry? What can I do to help him develop?",
"As a parent how can we foster kindness and empathy in our young children. What reward system would most accurately incentivize kindness and empathic behaviors?",
"In case you are still taking questions! \n\nHave you found that there is an age in which populations have a pattern of reaching \"peak empathy\"? To rephrase, do people younger than 18, or in their mid 20s, or in their late 80s, etc. experience more/less empathy than other age groups?"
]
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|
[] |
[
"https://twitter.com/zakijam/status/1131953030461394944",
"https://www.penguinrandomhouse.com/books/550616/the-war-for-kindness-by-jamil-zaki/",
"https://www.amazon.com/War-Kindness-Building-Empathy-Fractured/dp/0451499247/ref=tmm_hrd_swatch_0?_encoding=UTF8&qid=1547223297&sr=8-1",
"http://ssnl.stanford.edu/"
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19thn7
|
Does Anybody have any information on the "Phantom Divisions" of the United States Army during World War II? (Cross Posted From r/Military)
|
I cannot find a whole lot of information about them. Just to name a few:
6th Airborne
9th Airborne
15th Armored
38th Armored
11th Infantry
157th Infantry
5th Motorized
I came across the 9th Airborne while reading an article; upon doing some research I found upwards of thirty "Phantom Divisions." I'm just curious who they were and what their function was.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/19thn7/does_anybody_have_any_information_on_the_phantom/
|
{
"a_id": [
"c8r7c4o"
],
"score": [
2
],
"text": [
"Could they be similar in role to the [Ghost Army](_URL_0_)?"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Ghost_Army"
]
] |
|
6qrwya
|
why does it seem easier to get stuck in a comfort zone as an adult?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6qrwya/eli5_why_does_it_seem_easier_to_get_stuck_in_a/
|
{
"a_id": [
"dkzj3u9"
],
"score": [
2
],
"text": [
"In the old days, life changed very slowly. The way the world worked when you were 5 years old was the same when you were 75 years old. So by the time you had reached adulthood you pretty much had figured out what there was to figure out."
]
}
|
[] |
[] |
[
[]
] |
||
12ztqx
|
Constellations disappearing:
|
Hey how long until our beloved constellation disappear from our sky? Big dipper ( Plough) seems to missing a star tonight.
|
askscience
|
http://www.reddit.com/r/askscience/comments/12ztqx/constellations_disappearing/
|
{
"a_id": [
"c6zjex4",
"c6zjxkb"
],
"score": [
3,
3
],
"text": [
"Stars rarely just go missing, but the constellations will change over time due to stars moving at different velocities. Here's [what some of them will look like in 50,000 years](_URL_0_).",
"If it's a particularly bright or hazy night, sometimes the faintest stars in constellations can be hard to see. There are 4 stars in Ursa Minor which are of magnitudes 3, 4, 5, 6, (I think those are the numbers, I'm not certain) and based on how many of those you can see, you can estimate the limiting visual magnitude on that night."
]
}
|
[] |
[] |
[
[
"http://news.discovery.com/space/changing-constellations-50000-years.html"
],
[]
] |
|
a0s2ct
|
Why did Britian use the bolt action Lee-Enfield as their primary battle rifle when repeating technology (M1 Garand, Gewehr 41, etc) was already developed and working?
|
I get that the Arisaka and Mosin-Nagant were also bolt action, so it's not like repeating clip-fed rifles were the world standard by any means. It's just that given that Britain was a powerful empire at the time, you'd think that their firearms technology would be sort of top of the line you know?
Also, I'm not shitting on the Lee-Enfield by any stretch. I get that it was a very effective weapon and I respect it. Am I overestimating the difference in effectiveness between a repeating rifle and a bolt action rifle?
I also understand that they had Browning machine guns, Brens, and other fully automatic guns and that they still fired off plenty of lead. I'm asking specifically about why their main infantry rifle seems to have been a little behind tech wise.
& #x200B;
EDIT: Forgot to mention in the title, but obviously I'm talking about World War II here.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/a0s2ct/why_did_britian_use_the_bolt_action_leeenfield_as/
|
{
"a_id": [
"ec6nwoj"
],
"score": [
2
],
"text": [
"hey, sorry for the very late answer, i hope i don't break any rules by digging up old unanswered questions.\n\nTo answer this question you have to understand how the adoption of a self loading rifle would have worked in britain in the 1930's. \n\nTo get a new rifle adopted, someone in the board ordnance has to be persuaded to the idea of mass issuing a self loading rifle to the rank and file of the British army. Already we are fighting an uphill battle for the following reasons.\n\n > A very limited amount of choice in rifles\n\n halfway the 1930's there was a very limited amount of options for a self loading rifle. If we exclude all designs that aren't able to fire full power .303(the British standard munition of the time)or other full power rifle rounds we are left with weird enfield conversions and unproven prototypes(most of which they aren't even aware). \nThe belgian design ( the later fn49) and french design(the later mas49) were still secret and incomplete at this time too. \nThere is the pederson with a toggle lock, which causes problems in itself. And he zh29, familie of the zb-26(the gun the bren was designed on), but it also has problems that make it unsuited for mass adoption.\nThe most realistic options would be the then avs36(later svt40) and the m1 Garand.\nBoth those rifles would be patented so just copying them would not be an option. Lincensed production is very expensive and thus not really an option. Britain also still has a large arms production industry at this time, so they would design it themselves most likely.\n\n > .303 british\n\n.303 is an obsolescent round at this time, it underperformed compared to other cartridges of it's time and was expected to be replaced in the 1910's with .276 enfield, but testing showed some problems with the munition and ww1 halted this change completely.\nThe problem with .303 is that it is a rimmed cartridge , this causes issues when designing magazines and feed systems as there is a possibility to get the rims of the rounds caught on each other and causing so called 'rimlock'. Fully rimmed cartridges are fine for belt feds, but are very undesired for magazine fed solutions. There are ways to minimize rimlock, but no sane person would design a brand new mass issued main infantry rifle in .303(unless really desperate)\n\nBut changing to another caliber is not really an option at this time, the British empire has a massive stockpile of weapons and ammunition from ww1, and re-barreling existing vickers and enfields and producing all the new ammo is something that the british empire does not want to do in the economic depression of the 30's. They also just adopted the bren in.303 so .303 was there to stay.\n\n > Massive stockpiles of enfields\n\nLike is said in my last paragraph, the British empire has an absolute massive stock pile of enfields of various types in their armories. Most of them were converted to the latest patern or were in the proces of being converted. Building a new self loading rifle and spare parts, and then producing enough for the whole armed forces, takes a lot of time and money, both of which britain didn't want to spend on this. \n\n > Doctrine and tradition\n\nThe British army had a well established infantry doctrine, and the enfield was an important part of it. Those guys loved their enfields, changing to a self loading rifle would require changing doctrine and military tradition, something generals at the time wouldn't have been keen on. \n\nThe British military command took years to remove the magazine cutoff from the enfield, a feature that was almost never used.But some people clinged to it for some odd reason, changing their mind about enfields would be even harder.\n\nAnd we have to be honest here, a self loading rifle is better than a bolt-action, but the self loading rifle you would get at this point would not be a massive improvement. Add to this all the loss of experience with the platform and the gains would be fairly limited.\nAdditionally they would have to rewrite manuals , retrain soldiers, change the logistics as they would undoubtedly use more ammo and so on. These things all take a lot of time. \n\n\nSo if we take all of this together, and we place our selfs in the shoes of the British person at the board of ordnance.\nWe would have to do the following to adopt a selfloading rifle in the 30's :\n\nFirstly we have to design it in Britain because there aren't any real viable designs on the market, and use another cartridge as .303. Which we do not want to do at this time, and if we designed it with .303, we would have to spend time and money preventing problems caused by the cartridge.\n\nThen we have to pass military trials and probably refine the design, then probably do trials again(with the refined rifle).\nThen we have to convince even more generals and the rest of the board of ordnance that this self loading rifle is so much better than their tried and trusted enfields, and that their budget should not be spent on other things like more bren's, vickers, tanks, ... .\n\nAfter all of that we have to refine the design for mass production(not always the case but prototypes are not mass production friendly most of the time.), and tool up one or several factories, creating jigs, tools, milling machines... .\nAnd the military command has to rewrite arms doctrine, and formulate a new manual of arms for the rifle, and so on.\n\nAfter all of that we are probably in the same boat as france, russia, poland and belgium, they started development fairly early, hit some snags and before they could produce any meaningful number of rifles, ww2 had started.\n\nAdopting a self loading rifle during the war is even worse, after dunkirk the british needed to rearm a very large part of their army. They needed to start cranking out rifles, submachine guns, bren's, tanks, ships,aircraft,..., by the millions. The massive undertaking of designing a new rifle and retooling factories at that time is all but impossible.\n\nThe USA was the only country to field a self loading rifle as their standard infantry rifle in ww2, they did not face many of the problems European nations faced for developing a new self loading rifle. And even then it took garand years to get his design right, and for production to ramp up.\n \nAs for the g41, that rifle entered the scene when the war had already started and had some major flaws in itself. Most notably using the bang system to trap gas, instead of a hole in the barrel. Therefor it was never issued in any large numbers.\n"
]
}
|
[] |
[] |
[
[]
] |
|
nvxvz
|
conservation of mass says matter can't be created nor destroyed. do we have any theory of how this fundamental law was originally ignored to create the big bang?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/nvxvz/eli5_conservation_of_mass_says_matter_cant_be/
|
{
"a_id": [
"c3ch6sp",
"c3ch6sp"
],
"score": [
7,
7
],
"text": [
"The original question not entirely accurate. Mass/energy (they are the same thing) cannot be created or destroyed, but mass *can* be turned into energy, and vice versa. \n\nNuclear reactions attain their vast energy outputs by converting a small (but non-trivial) amount of mass into energy. Even chemical reactions are theorized to do the same, but obviously a far smaller amount. In both cases, the total mass/energy remains the same before and after the reaction occurs.",
"The original question not entirely accurate. Mass/energy (they are the same thing) cannot be created or destroyed, but mass *can* be turned into energy, and vice versa. \n\nNuclear reactions attain their vast energy outputs by converting a small (but non-trivial) amount of mass into energy. Even chemical reactions are theorized to do the same, but obviously a far smaller amount. In both cases, the total mass/energy remains the same before and after the reaction occurs."
]
}
|
[] |
[] |
[
[],
[]
] |
||
el8qip
|
The Norse people were shown to be capable raiders, especially in the British Isles. The Anglo-Saxons despite divided were socially and militarily organised, why did they, or others, never seek or attempt to attack Scandinavia?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/el8qip/the_norse_people_were_shown_to_be_capable_raiders/
|
{
"a_id": [
"fdgkrzb"
],
"score": [
184
],
"text": [
"I afraid that I cannot offer a single definitive answer to 'why X didn't Y' type question of OP. Instead I'll make some corrections to OP's premise below. \n\nFirst of all, there was no known unified large-scale kingdom in Scandinavia before the middle of the 10th century (until the rise of the Jelling dynasty in Denmark), possibly except for the kingdom of the Godfred family in its southernmost part (Southern Denmark) in the early 9th century. Three Nordic medieval kingdoms, that is to say, Denmark, Norway and Sweden have primarily been political products since the last decades of the first millennium. In other words, it was not so likely that the majority of the Norse raiders in the middle to late 9th century were under the direct influence of one of such rulers in the unified kingdom, though some Frankish rulers might have misunderstood so that they tried to negotiate the ruler of 'the Danes' to deal with the onslaughts of the raiders mostly in vain. \n\nApart from the apparent problem, navigation durability of the fleet of any non-Scandinavian power at that time from their homeland to Scandinavia (that I personally have much doubt), to annihilate or to conclude a treaty with one or two polities (petty kingdoms) in Scandinavia around 900 to stop raiding would not have eliminated the threat of Norse raiders' invasion since there were probably much more polities remained than the fleet could possibly handle. \n\nAnd yes, there were indeed some attempt of non-Scandinavian European powers, especially some German rulers, to invade the southernmost part of Viking Age Denmark in the 10th century, as I illustrated in [The Danes or Vikings from later Denmark would often raid the Frankish Empire and later what would become the Holy Roman Empire. How were they so successful and how did the Danes avoid being conquered by the big powers?](_URL_0_). I suppose that main force of such German invasions comprised of cavalry and infantry, not the fleet, as long as attested in narrative sources and based on the location of the battlefield (Danevirke, the palisade built by Danish rulers). \n\nOn the other hand, I should also point out the fact that not all the Norse raiders didn't probably directly came to the British Isles from Scandinavia. Many Viking war bands were active around the British Isles as well as the English Channel in the middle of the 9th century, and now researchers suppose that they kept 'stayed' in this area for more than a few years, and sometimes took shelter in one of 'their' new political centers nearby, such as Dublin in Ireland or Rouen in Normandy, or further, York in Northern England, instead of Scandinavia. Then, targeting one of these 'diaspora' polities rather than distant petty kingdoms in Scandinavia would be much more realistic and successful tactic against the Norse raiders, and some local rulers actually did so (note that the Norse ruler was once expelled from Dublin in the early 10th century (from 902 to 917)). \n\nReferences: \n\n* Brink, Stefan & Neil Price (eds.). *The Viking World*. London: Routledge, 2008. \n* Garipzanow, Ildar H. 'Frontier Identities: Carolingian Frontier and the Gens Danorum'. In: *Franks, Northmen, and Slavs: Identities and State Formation in Early Medieval Europe*, ed. Id., Patrick Geary & Przemyslaw Urbancyzk, pp. 113-43. Turnhout: Brepols, 2008."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/cvzcjo/the_danes_or_vikings_from_later_denmark_would/"
]
] |
||
1f7823
|
What happened to Dutch painting in the 18th century?
|
Last week I visited the Rijksmuseum and grew interested in Dutch masters and the history of art in the Netherlands. I noticed that both wikipedia and the Rijksmuseum website skip the 18th century in the chronology of painting in the Lowlands without any explanation.
A bit of google later I'm still without a satisfying explanation. Sure, perhaps they regarded the previous (Golden Age) century as the apogee of painting that couldn't be surpassed, which didn't help pushingany new developments and led to a more reactive art scene. But did it completely disappear? I also understand that painting became quite affordable in the 17th century, so surely there still was a large demand in the 18th century?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1f7823/what_happened_to_dutch_painting_in_the_18th/
|
{
"a_id": [
"ca7nv92"
],
"score": [
3
],
"text": [
"Apparently during the 18th century the Dutch Republic was seen as being in a decline. Instead of commissioning new works by comtemporary artists, patrons preferred to obtain works from the Golden Age, when their country was more stable and prosperous. And in 1718, Dutch artist Arnold Houbraken published his first volume of biographies of Dutch and Flemish artists, which \"initiated a retrospective assessment of the artistic production of the past century, and thereby marked its end.\"\nSource: A Worldly Art: The Dutch Republic 1585-1718 by Mariet Westermann"
]
}
|
[] |
[] |
[
[]
] |
|
5m4mzf
|
how does an led change colors?
|
Is there any mechanical or physical change? Are there multiple different colored LEDs in each "bulb" that are illuminated in various configurations to produce each color (similar to an RGB display)? Or can one unit actually produce light of variable wavelengths?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5m4mzf/eli5_how_does_an_led_change_colors/
|
{
"a_id": [
"dc0tofc",
"dc0tq45",
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"dc0v6c4",
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"dc12pdl",
"dc1buyc"
],
"score": [
110,
2,
50,
4,
4,
2,
4
],
"text": [
"A color changing LED isn't one LED in a package but three LEDs along with a small computer to drive them. The LED is made up of red, green and blue LEDs each of which can be controlled by a microcontroller. Since the two legs on the LED that supply the power are connected to the microcontroller and not the LED elements a current limit resistor is not required.\n\nThe microcontroller is able to turn each of the colors on or off, so if the red LED is turned on then the output from the color changing LED is red. When the blue LED is turned on it is blue, if both the blue and red LEDs are turned on then the color changing LED is a shade of purple (called magenta). Similarly combining red with green gives yellow and blue & green gives cyan.\n\nAlthough the color changing LED uses the six colors mentioned above, it slowly changes from one to another. This is still done using the three basic red, green & blue elements. If the red LED is combined with the blue LED, but the blue LED is only driven at 50% of its normal brightness then a color half way between red and magenta is generated.\n\nWhilst the red LED is left turned on, if the blue LED is slowly taken from 0% brightness to 100% brightness then the color will gradually change from red to magenta.\n\nIf a standard LED is turned on and off very quickly, say 100 times every second then as far as the human eye is concerned it looks like it is constantly on. If the amount of time the LED is on for is the same as the time it is off for then it will be on for 50% of the time and 50% of its full brightness.\n\nThis same method can be done with the three LED elements inside the color changing LED. This means it is possible to combine any amount of the red, green and blue to give the desired color. Looking once again at the change from red to magenta, if the blue LED starts mainly turned off, goes to being on and off in even amounts and then to mainly being on then the the color will change as required.\n\n[Source](_URL_0_)",
"Multicolor LEDs generally have an element for each color. There are RGB LEDs as well. Color can also be slightly adjusted by changing the operating voltage. \n\nEdit. Each element color, they can then be turned on in combinations to make other colors. ",
"Masters Electrical Engineering. Most RGB LED have all three colors in them. You then light a specific one my applying power to the color you want. If you look at large LEDs that can do RGB, they have 4 prongs coming off. You then power the prong you want an bam! Color. One for ground, and then each color gets a prong. If you make a super small RGB LED and then combine a bunch into a massive array, you get a tv.\n\nYou can do it with a single light source, then apply a polarizing filter. The filter is controlled by a small current. This can produce colors as well and is the idea behind LCD displays.",
"An older style of multi-colour LED is the type that have a red and a green LED in the one package. They usually have three legs. \n\nDespite having a red and green LED, they can actually display a third colour. Light them both and you get yellow, because red and green light combined give you yellow light. ",
"As most have said, they typically contain a red, green, and blue LED in one package. \n\nJust wanted to point out: this is also how a TV or computer monitor works. There is a red, green, and blue pixel in a pattern over and over.\n\nBy controlling each color, you can basically make any color.",
"Here's a [close-up of a surface mount RGB LED](_URL_0_) that shows you what's going on inside.\n\nYou get different colors by combining the red, green and blue in student quantities. To dim one of the colors, you switch it on and off very quickly. The higher the ratio of on time to off time, the brighter it is.\n\nThey'll often have a diffusing cover to blend the colors together.",
"Wow thanks everyone! That would have taken me hours of googling and synthesizing information from multiple sources. This is more than I wanted which is even better. "
]
}
|
[] |
[] |
[
[
"https://www.kitronik.co.uk/blog/how-color-changing-leds-work/"
],
[],
[],
[],
[],
[
"http://a.pololu-files.com/picture/0J5009.1200.jpg?0e2e4f4467017720224a1f46c397c8c7"
],
[]
] |
|
1k5iqn
|
How will it affect US economy if bill gates were to transfer all his money to some other country ?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1k5iqn/how_will_it_affect_us_economy_if_bill_gates_were/
|
{
"a_id": [
"cblobpm"
],
"score": [
3
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"text": [
"The exact disposition of Bill Gates' personal wealth isn't information we can get our hands on, since he's a private citizen and it's none of our business. So instead let's make up a person with the same order of magnitude of wealth, imagine how he would store his wealth, and then answer the question based on that.\n\nSo here's Mr. John Smith, with a net worth of $100 billion, making him very wealthy indeed. To keep things simple, let's assume he carries *no debt at all* (which is implausible in the extreme), so his net worth comes from just the sum total of the value of all his assets.\n\nWhat exactly are those assets?\n\nWell, let's say that a *very small fraction* of that wealth is in cash. Everybody needs to deal in cash transactions on a regular basis (paying for lunch, putting gas in the car and so on), so let's say that Mr. Smith has cash holdings with a value of … oh, let's say $100,000. Just to pick a figure. That's the account he spends his money out of, to pay the electricity bill and such like that.\n\nWhere exactly is that money? If we imagine that it's sitting in *cash* — literal currency, like bills and coins — in a vault somewhere, we'll be quite wrong. Mr. Smith *could* store his cash assets that way, but he doesn't, because that's not a reasonable thing to do. Instead he keeps his cash holdings in a bank account. In that form, his cash wealth (which remember, has a value of $100,000) exists as a *liability* on the books of his bank. Basically, that means Mr. Smith goes to the First National Bank of Wherever and says \"I will give you $100,000 if you promise I can come ask for it back whenever I want.\" The bank says sure, and takes his money, and in return gives him their promise that he can withdraw it at any time. That makes the bank *liable* to Mr. Smith for that money.\n\nIf Mr. Smith wants to move that money overseas, it's no problem at all. He simply goes to the bank and asks for whatever cash they're liable to him for. The bank provides it in whatever form Mr. Smith prefers (currency, or more likely a bank check), and Mr. Smith goes about his merry way. The bank can do this because *banking regulations require* banks to be able to give their depositors the money they're owed whenever they're asked for it. So the bank will always be able to give Mr. Smith what he asks for. If the bank ever *can't* give Mr. Smith what he asks for (as well as all their other depositors), the bank will be *insolvent,* and a regulatory organization called the FDIC will step in to conduct an orderly closure of the bank and transfer of its assets and liabilities to another institution.\n\nSo all that is a very long-winded way of saying that if Mr. Smith wants to withdraw his cash and put it in another bank overseas, he will have no problem doing so, and there will be no effect of his doing so, because banks are regulated to make sure that's true.\n\nWhat about the rest of his assets? Well, Mr. Smith keeps them, as any reasonable person would, in a diversified collection of various things of value. We can broadly divide that collection into two categories: Things which are *easy* to sell, and things which are *hard* to sell. Things that are easy to sell include shares of mutual funds or stocks, for example. Those are things which a great many people want all the time, so if Mr. Smith decides to sell them, he'll have no trouble at all finding a buyer.\n\nLet's imagine Mr. Smith owns 10,000 shares of a particular mutual fund. If he wants to, he can sell those shares at whatever the current market price is, then take the cash and deposit it in his overseas bank account. This will be very easy for Mr. Smith to do; it's just a phone call to his broker, who just has to put a sell order into his computer and then cut Mr. Smith a check for the profits. Mr. Smith then takes that money and sends it to his new overseas bank, where it gets credited to his account.\n\nThat's generally true of all of Mr. Smith's *liquid* assets — that is, assets which are very easily converted into cash. He can sell them quickly and easily for pretty much their nominal value, and then take the cash from those sales and do whatever he wants with it.\n\nSo now Mr. Smith has the $100,000 in cash he withdrew from a US bank and deposited into an overseas bank … and also some huge sum, in the billions of dollars, he had invested in securities which he liquidated and deposited in his overseas account.\n\nBut what about the rest of Mr. Smith's assets? His home, his furniture, his car, all those things? These are called *illiquid assets*, which generally means they're hard to sell. In order to sell his house, Mr. Smith needs to find somebody who wants to buy it. That's not guaranteed to be an easy thing to do! In fact, Mr. Smith might be unable to find *any* buyer for his house without lowering his price to some small fraction of what his house is nominally worth. So either he can choose to sit on those illiquid assets until he finds a buyer for them, or he can sell them at a loss to get out quickly.\n\nSince the premise of the question is that Mr. Smith wants to \"transfer all his money to some other country,\" we'll assume that he wants out even if it costs him money. So we'll say he sells all his illiquid assets for pennies on the dollar. The result here is pretty obvious: Mr. Smith's net worth goes down! He converted assets with a certain nominal value to cash of *less* value, so he's worth less money in total. But the good news is now he has his cash, so he can send that to his new overseas bank as well and deposit it.\n\nNow Mr. Smith has successfully moved all his money to \"some other country.\" What's the net result on the US economy? Essentially none. Mr. Smith's cash holdings were very small, and the bank had no problem covering their liability to him, so that doesn't have any effect. All his liquid assets — shares of stock, mutual funds, bonds and so on — were easy to sell, so other buyers snatched them up at fair market value and no significant change in wealth occurred there; assets just changed ownership. Mr. Smith sold off his *illiquid* assets at a loss, so he took a hit, but other parties got a bargain, so the net result there is pretty much nil as well.\n\nBut of course, now Mr. Smith has a problem. See, all his money (less the losses he took from liquidating his holdings) is in *cash,* and that's not good. Mr. Smith now has to turn around and use his cash to *buy more assets,* so his money can earn him an income. In so doing, he ends up investing his money *right back into the same companies he was holding before,* because they're still the right choice for him. Along the way, Mr. Smith has to cover certain fees incurred by selling and buying securities, so he loses some money, but the total overall net result on the economy is … well, absolutely none, really. Assets changed hands, and a little wealth was created and a little wealth was destroyed, but no significant effects occurred … except for Mr. Smith having to do a heck of a lot of paperwork for no real reason."
]
}
|
[] |
[] |
[
[]
] |
||
awghnc
|
Is there a way to conceptualise complex integration?
|
So I understand real integration fine and I think this is because I think very visually and it is very easy to do this with real integration as its area. Today though I started to play around with complex integration and I'm starting to realise I can't use the same area trick anymore... I think. This confusion is stemming from the Cauchy Integral Theorem I don't understand how the integral is always zero and I can change the shape (with rules) under deformation and its still zero! I feel like area is no longer playing here or is it just hidden in a sense, any explanation of what going on would be greatly appreciated!
|
askscience
|
https://www.reddit.com/r/askscience/comments/awghnc/is_there_a_way_to_conceptualise_complex/
|
{
"a_id": [
"ehmu3i1",
"ehqopoj"
],
"score": [
4,
2
],
"text": [
"In complex analysis, an integral is less like the \"Finding the area under a graph\" integral of calc 1, and more like the line integrals of vector fields in calc 3. These path independence results are actually there in normal multi-variable calculus. In this context, integrating a differentiable complex function is similar to integrating on a conservative field, where the path doesn't matter. ",
"You still have the \"adding up little bits\" intuition; just not bits of area. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
3impk0
|
cannabis strains classification.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3impk0/eli5_cannabis_strains_classification/
|
{
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"cuhsc82",
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"text": [
"It's both. There's a classification system to differentiate between plants, and from the same family of plants.\nAnd with cannabis, naming the strains means that you can get the same product again without confusion; but you can name any strain the name you want. There's no science behind that.",
"That Wired article misses one major problem with the black market - there's no way to tell by looking at it if your \"blueberry kush\" is really a \"blueberry kush\". You don't have paperwork tracing it back to a reputable breeder/grower, you just have to rely on the last guy in the chain being honest (or un-stoned enough to remember).\n\nThere's nothing stopping somebody from deciding to label their boring mid-grade weed (or even some unrelated high-grade) as \"blueberry kush\" because they know that's what everyone's looking for this month.\n\nWhen you have legal marijuana sold in dispensaries, you start seeing them analyze each batch in a lab & give you actual ratings on how much of each of the different chemicals are present in the plant. You're also buying from suppliers that can generally be trusted to *not* mislabel their shit.",
"Imagine a line with Sativa on one end, Indica on the other end, and Hybrids in the middle. Sativa has more THC, while Indica has more CBD. Hybrids are a mix, for example, 60/40 THC/CBD. THC is more of a \"head high\". CBD is more of a \"body high\". So, cannabis is exquisitely customizable. For instance, if you just want something to make you sleepy, and pain free, go with a heavy Indica strain. If you want something to make you get \"high\" and experience a mind altering experience, go with a pure Sativa. Or if you want a blend, Clear Head, Numb Body, go with a Hybrid. I'm from Colorado. If you walk into any weed shop they are very knowledgeable and will ask you specific questions about what you are seeking and customize a solution for you on the spot. The \"names\" are meaningless. What you want to ask is the blend of Indica and Sativa (CBD/THC) that you are getting. The names are just names. What you want to do is be very specific with your bud tender and tell them exactly what you want to get out of it. Do you want to watch movies and giggle, or do you want to melt into the couch and zone out? Are you looking to get rid of pain or just go \"on a trip\"? Be specific and they will know exactly which strain to recommend. ",
"Just ask your customer what their favorite strain is. Then in two weeks, call whatever weed you have to sell that strain. It's worked for more for well over 10 years without a single complaint."
]
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3bpxp5
|
Why are siphonophorae considered "colony organisms"? What's the difference between a morphologically specialized zooid and an organ?
|
Why was a distinction needed? The zooids share the same DNA, comes from the same egg, are non-mobile respectively to one another and are incapable of surviving on their own.
(and even if some segments of their organisms were able to survive and regrow if cut from the rest of the body, the starfish, which aren't considered colony organisms as far as I know, have the same ability).
So where is the distinction?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3bpxp5/why_are_siphonophorae_considered_colony_organisms/
|
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"the distinction is made based on the origin of the zooids\n\nin everything from a fruit fly to a human the first fertilized cell divides many times into a mass of cells, aligns itsself along some gradient and develops bands of cells with know fates \n\nsiphonophore cells bud off the first fertilized cell with their fate seemingly already determined. as you pointed out the function is the same but the development is distinct ",
"We consider siphonophores to be a colony organism because of how they develop and are organized compared to other cnidarians.\n\nThe cnidarians body plan generally falls into one of two categories. The medusa or the polyp. The most common example of a medusa form cnidarian is a jellyfish, and a common example of a polyp would be a sea anemone. \n\nMany cnidarian species use both forms during their life cycles. Most jellyfish species start off life as a polyp, which often forms an asexually reproducing colony before transitioning to the free swimming adult medusa.\n\nOther cnidarians also grow as colonies but remain that way for their whole lives. Corals for example reproduce asexually and spread just like jellyfish polyps, though they form a skeleton around themselves. We don't consider a coral colony to be a single organism even though they work together to build the skeleton and have the same DNA. But in many species connections are retained between the polyps that let them share food and resources.\n\nSiphonophores are simply a more advanced version of this same process. They're a colony of organisms that each have specialized function, be it feeding, swimming, defense, reproduction, or what have you. The level of organization is higher than with corals, but the system is basically the same.\n\nSome siphonophores don't reproduce directly. Instead they live as a colony that releases zooids from time to time in the form of medusa, jellyfish-like organisms that are capable of living completely independently. These medusa-zooids are known as eudoxids and they are the sexually mature form of the species. They're the ones that reproduce sexually to make new eggs that develop into siphonophore colonies again.\n\nThe amount of diversity among siphonophores is simply staggering. Some have the free swimming eudoxids like I mentioned, and in some species these eudoxids can even bud off additional zooids that will also live as medusa, but they're unable to asexually produce a new siphonophore colony. \n\nOthers keep the medusa attached to the colony and release eggs and/or sperm directly from the main colony."
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1v19bw
|
Historians, how many of you speak/ have fluency in languages relevant to your areas of study? How important would knowledge of such relevant languages be to you?
|
Mods, sorry if this violates the "no poll questions" rule, but I'm interested to know how many professional historians actually do speak relevant languages. I'm not so interested in people studying european history- mostly, I'm curious about people like /u/Qhapaqocha, our andean specialist, and others who work in fields that would require languages without large knowledge bases.
Thanks!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1v19bw/historians_how_many_of_you_speak_have_fluency_in/
|
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"Before I refocused myself into Early Modern France, I was aiming to be a Classicist with a focus in the Late Roman Republic, so I had to learn Latin and Ancient Greek, the latter of which is still useful in my current focus on Early Modern France since the Habsburgs wrote laws in Latin first.\n\nI am to learn French and Germany to further my ability in the subject as there are a lot of sources that haven't been translated or books that remain in their local language.",
"I'm studying for a BA in medieval studies, with emphasis on the British isles. Relevantly, I speak pretty good Latin, tolerable French, good Middle English, and beginning Old English. Less relevantly, I speak tolerable German and Spanish.",
"I work in ancient materials, so it's reading, not speaking that's needed. Reading wise, I'm pretty solid in Hebrew and Greek, ok in Syriac. In terms of modern academic languages I can read/write/speak German pretty well. I got a relatively late start on languages and actually consider myself somewhat behind. Before completing the PhD I'll need two languages more minimum, and preferrably four. ",
"Latin American historian here. To graduate with a Ph.D. from my university, it was required that we have fluency in one foreign language relevant to our field, and reading knowledge of a second. I have fluency in Spanish, and reading knowledge of Portuguese. The Spanish is absolutely essential to me, and I use it constantly. I literally couldn't do my job without it. The \"reading knowledge\" of Portuguese I picked up in a six week class that basically taught what minor differences there were from Spanish. I wouldn't really say I'm fluent in any way. I can generally get the gist of what written things say. Honestly, I may find the Portuguese knowledge useful about once a year for something that I probably could have figured out about as well on Google Translate. \n\nI will say that if I wanted to, I could go back to my same university (which I still live near) and pick up Mayan, Nahuatl, or Quechua, which are all offered as classes. Of those, Mayan would likely be the most useful to me, since I focus on Cuba and Mexico.",
"Studying African history, you would assume that speaking an African language would be useful. However, as I focus on colonies and the post-colonial period, nearly every written source is in English; government documents, memoirs, newspapers, etc. I was lucky enough to learn Afrikaans growing up which means I can make use of any journal articles published in Afrikaans (not that there are many) and I learnt chiShona to help me converse with people when conducting interviews, but honestly, I could do as well just knowing English. However, I have found that despite the majority of people I have interviewed speaking English fluently (you would be hard pushed to find anyone outside of the really rural parts of Zimbabwe who doesn't have a good grasp of English), they really appreciate you making the effort to converse in their own language. It makes them a lot more comfortable and, in my opinion, makes it a lot easier to actually have a conversation with them.\n\nAs a side note, I'm currently learning Portuguese (when I can!) to help with possible future work on Mozambique - now that is a field in which lots of work done is not in English, so Portuguese really is a necessity!"
]
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4uxjwq
|
why airlines don't sell empty seats on flights at cheap rates
|
I was at the airport recently waiting for my flight, and looked up prices for last minute tickets as it was relatively empty - they were all over $500. So it got me thinking, why would an airline rather not fill the seats, than to sell them at deeply discounted rates? Is the actual cost of transporting a person on a plane so high, that it wouldn't be worth it for them?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4uxjwq/eli5_why_airlines_dont_sell_empty_seats_on/
|
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"Because people who purchase tickets last minute usually *have* to travel and will pay the full price.\n\nIt's rare that a plane will be relatively empty. When that happens, it's probably just a fluke. If a route regularly has a lot of empty seats, they airlines will drop one of the flights and put it on a more profitable route.",
"If airlines offered last minute cheap seats, no one would book too far in advance. \n\nBecause last minute flights are expensive, people book early to save some money, and if their plans cancel, they lose out on the cost of the flight. \n\n",
"Airline companies have a goal of maximizing profits. They do part of this by charging different prices for tickets on the same flight. Their goal is get as much money as possible per flight. They prefer to know how full a flight is going to be earlier, so they can adjust their price accordingly. A flight that is mostly full two months before it takes off will see a large increase in price. Airlines know that the majority of people who buy tickets closer to the departure date need to go and will pay a higher price to do so. If the day before, they dropped prices until every seat was filled, many people (i.e., the ones who let the airline know a couple months in advance how full an airplane will be) would in turn wait until that predictable event to buy the cheap tickets. Airlines would thus lose money because they could not determine the demand for the flight beforehand, and would essentially be filling most of their airplanes at the last minute. ",
"They do. It's called flying \"standby\". Generally you can only do this if you have a flight later that day and want to switch to an earlier one or if you are an airline employee or have a 'buddy pass' from an airline employee. You have to arrive at the airport early and are not guaranteed the flight. You can't book it in advance.",
"Actually, many airlines did this in the early days of the Internet. I was a member of Northwest CyberSavers (edit: in the mid-late 90s) - each wednesday they would publish select supercheap fares good for that weekend.\n\nSince the programs universally no longer exist, I must conclude they were overwhelmingly not profitable, or not profitable enough. "
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1c07io
|
Part 1: What causes a person with Tourette's to shout obscenities? Part 2: What would happen if they never learned any curse words?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1c07io/part_1_what_causes_a_person_with_tourettes_to/
|
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"I would just like to point out that not all verbal tics are curse words— [here is an article about a woman with Tourette's Syndrome who involuntarily says the word \"biscuit\" ~900 times an hour.](_URL_0_) The article also mentions that\n\n > \"Fewer than 10 percent of all patients [with Tourette's] swear or use socially inappropriate words.\""
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[] |
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"http://abcnews.go.com/Health/tourettes-syndrome-woman-biscuit-16000-times-day/story?id=17344295#.UWRgias8Qi8"
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||
ekuabf
|
why can't we use the ocean to dump onto fires?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ekuabf/eli5_why_cant_we_use_the_ocean_to_dump_onto_fires/
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"So... What about an intercontinental seawater highway? Or a water version of the electric grid? Could we, over time, create a set of pipes (an interconnected series of tubes perhaps? ;-) ), that carry sea water across the nation? Desalinization is still a problem, but it sounds like transporting the water is another problem that could be solved. If we had a water grid, desalinization facilities could be feeders off this grid.",
"In the recent California wild fires I saw planes and helicopters picking up water from the ocean to fight fires. They treat it to be a reddish color with a fire retardant then drop it from the buckets or fuselage.",
"Would it take too long to desalinate the water before dumping it on the fire?",
"In some cases we do. My city has powerful backup pumps that can draw directly from the bay in an emergency. The fireboats also pump saltwater directly. I believe the water bombers will use salt water if it is what is closest but it is rarely so.\n \nThen there's the matter of pressure. A million gallons of water does no good if you have no way to get it onto the fire. The civil water system is typically gravity fed which provides extremely reliable and consistent pressure. For the amount of water usually needed to fight fires, it is much easier to just tap off the municipal system than to built an entire parallel network of standpipes.",
"This problem is recurring right? after the fire everything grows back. Use salt water to impede the rapid re growth. Don't use it on pastures of course. \n Here's a thought they use dynamite or some type of explosive to extinguish oil well fire's right (by creating a vacuum) . How about using a daisy cutter/other ordinaance or two to create the same effect",
"Saltwater changes the pH of soil and can really hinder the regrowth of plant communities. \n\nIf you consider an area that seldom receives rain then you have a very long time before enough freshwater (rain) has fallen to restore soil chemistry.",
"Sometimes you can. There are planes like the CL-415 (scooper) that can skim along the surface and pick up water. \n\nRough conditions (windy, large waves) will not allow the planes to do this. \n\nThe salt in the water can eat away at metal, so the equipment would need to be clean thoroughly after. \n\nThe planes only pick up 2000 or so gallons at a time, so unless the fire was right near the coast, and the ocean the only water source, it would not be a good choice for a water source.",
"We can and we do. A lot of harbors have firefighting boats that pump seawater on fires. That has limited reach.\n\nThe farther you get from the coast, the more complex the logistics get. Do you pick up the water and dump on the fire? There are planes that do that, but the loads are very limited. Do you pump the seawater to where the fires are? Very slow to deploy this type of system.\n\nThe reality is that if the fires are not very close to the coast, it is very complicated to put them out with seawater.\n\nForest fires are contained by cutting clear around the burning area to stop the fire from expanding.",
" > Why can't we use the ocean to dump onto fires?\n\nWe can, and do. However, most fires do not happen near oceans, so it's not a practical technique most of the time.",
"You absolutely can, but it's largely governed by proximity of water sources to the fire. We will take water from the best nearby source. If that's the ocean or a saltwater body of water, so be it. Source: firefighter and operator with NSW aviation command."
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2tt0j9
|
Tuesday Trivia | Missing and Destroyed Documents
|
(going to be out tomorrow so this is going up a little early - enjoy your extra time to write beautiful historical essays!)
[Previous weeks' Tuesday Trivias and the complete upcoming schedule.](_URL_0_)
Today’s trivia theme comes to us from /u/Artrw!
As an archivist, it pains me to admit this, but sometimes humanity’s records don’t survive. Sometimes through neglect, weather, or malice, they just don’t make it. So let’s give some of these documents their rightful eulogies. **What’s a document or record from your period of study that is missing or destroyed? What did it say, and how did it meet its end?** RIP historical documents.
**Next Week on Tuesday Trivia:** Inventions! We’ll be talking about the greatest technological breakthroughs of all time. From making fire to the… whatever was invented in 1995 because that’s the limit.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2tt0j9/tuesday_trivia_missing_and_destroyed_documents/
|
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"I wouldn't say it's destroyed (yet), but a lot of Phil Weigand's data is unpublished. Things like aerial photography from before agriculture became more intensive. Locations of looted shaft tombs and guachimontones. Profile drawings of looters pits in structures and tombs. Samples of ceramics from these looted sites. Even drawings of the sites he visited which were sometimes just sketches. His wife currently has all this data as far as we know, but she's not willing to let anyone look at it or see it unless you are going to enshrine Phil in the process. It's a shame, really. He was collecting data since the late 60s up until his death in 2011. We may never fully recover all the data he collected.",
"A number of the papers and documentation related to Anne Boleyn's trial, and that of her brother George and the other four men charged with adultery, are missing or destroyed. For example, no record remains the deposition Jane Boleyn, George's wife, apparently gave, which was a large part of the Crown's evidence against George and Anne.\n\nWith so much of the trial documentation missing, we still don't conclusively know whether Anne was guilty of some or all of the charges laid against her, though most historians now lean towards her innocence. (In contrast, Katherine Howard, Henry's fifth wife and Anne Boleyn's cousin, was almost definitely guilty of adultery on the face of the evidence.)",
"18 and a half minute gap in the Nixon tapes . . . .\n\nEDIT: Seriously though, the closing of the Chicago Municipal Reference Library is tragic not only for historians of the city but for historians of America. Though much was shifted to the Harold Washington Public Library, documents lost include:\n > The only collection of documents from other taxing bodies in Cook County, municipal codes pre-dating the 1871 Chicago fire, census information from 1890 to the present, original bids and contracts on construction of the airport transit systems, city planning documents, five-year plans for capital improvements, annual reports from every city department, maps of most underground conduits and above-ground airways, two million clippings from all daily newspapers in the area and 23 community and ethnic newspapers.\n\nWahhhhhhhhh. For the deets: _URL_0_",
"In October of 1833, William Henry Fox Talbot was visiting Lake Como, Italy and attempting to make sketches using a Camera Lucida. Unsuccessful, he began to think of another way to capture the image. He wrote a note to remind himself of potential experimentation on the idea of capturing an image. This essentially marked the first time William Henry Fox Talbot, the inventor of the Calotype, thought about any sort of photographic process. Since then, the note has been lost, but Talbot transcribed it into one of his many journals a couple months after writing the original note. The journal reads:\n\n > Nitrate of Silver. Wash a sheet of paper with it. Place a leaf of fennel or other of complicated form upon it. Press it down with a pane of glass - when blackened with the sunshine place it in something that will alter its property of blackening - qu. Prussiate of potash? Sulp. Acid. Mur Soda. Carb. Soda. Instead of the leaf try several bits of coloured glass - thus a silhouette might be taken, especially in a dark room.\n\n\nThese early ideas for experimentation are what led Talbot to create one of the first photographic processes in our history. I, personally, just think it would be interesting to see and preserve the note. Mostly because it could be labeled as a starting point for the experimentation of the Calotype.\n\n[Source:](_URL_0_) Roger Watson, Helen Rappaport. *Capturing the Light.* New York: St Martins Press. 91-94",
"Many silent films from the silent film era are (unfortunately) deemed lost. It's really sad to think that there are thousands of hours of film that no longer exist. There may have been movie stars that we have very little or no record of studying. ",
"Letters are excellent sources for the study of late antiquity and the massive *Register* of Pope Gregory the Great stands out even today due to the range of topics covered. He corresponded with emperors, kings and heretics from across the Christian world, making it an outstanding source for the end of the sixth century. Unfortunately, his successors' letter-collections were not preserved in a similar way and we have to make do with only a small number of letters preserved principally in the records of church councils (such as from the Lateran Synod of 649, the Ecumenical Council of 680 and the gazillion Councils of Toledo in Spain), so we get the impression that popes after Gregory were seemingly only interested in doctrinal issues, not political and administrative matters, which was obviously not the case. What is particularly fascinating is the fact that the seventh century was an extended crisis for the Byzantine Empire and that we have no contemporary Greek histories or chronicles to tell us what happened, so we have to reconstruct events from religious and non-Greek sources. From the sources we have, the papacy emerges as a shadowy power acting behind the scenes of major revolts and religious controversies, which I think is a very dramatic demonstration of how western bishops were still intimately involved in Byzantine affairs. \n\nSo what do we know? Pope Honorius I in the 630s had agreed to the monothelete doctrine proposed by the Byzantine emperor Heraclius and Patriarch Sergius of Constantinople, an act that must have angered many Chalcedonians in the west, yet from the sources we only hear of eastern dissidents. The papacy then did a volte-face after Honorius' death and condemned monotheletism openly from 640 onwards, which in my opinion directly caused a revolt by the Byzantine governor of North Africa in 646 - what wouldn't I give to read the letters exchanged between Rome and Africa at this time! Pope Theodore I also began to prepare for a synod to be held in Rome to condemn monotheletism, which was again a giant slap to the face of Constantinople. From the list of attendees, it is clear that it was an overwhelmingly Italian synod, yet records also indicate that there was support from Francia and Visigothic Spain, so why were there no attendees from the west? \n\nTheodore died before the council was held, so Martin I became the pope chairing the treasonous proceedings. A Byzantine exarch was sent to arrest the pope in the synod's aftermath, but for some reason the exarch turned against the emperor and began a civil war in Italy on the pope's side in 652! Again, we only have a few hints of what happened in this revolt; we have a few letters from Martin urging bishops across Christendom to side with him, so I do wonder to what extent did he urge for secular officials to join his side too. A bit later there were purges within the Byzantine aristocracy that can plausibly be tied to this too, so my pet theory is that the anti-monotheletes' influence was widespread across the empire and took years to be completely wiped out.\n\nThe exarch died soon after and Martin was arrested (for realsies) in 653. The next two popes were pro-imperial candidates imposed on Rome and they swiftly reconciled with the heretical emperor Constans II. This period is perhaps even less known, since both the papacy and the emperor after 680 (when monotheletism was condemned as a heresy) had no interest in preserving what happened in those years. Still, the hints we have are absolutely fascinating, since it looks like a North African monk served as an imperial ambassador to Francia and was seemingly involved in a plot to bring down Burgundy, whilst another monk, Theodore of Tarsus (incidentally one of the dissidents in 649), was appointed by the pro-imperial Pope Vitalian to the archbishopric of Canterbury. Was Constans II trying to extend imperial influence to Francia and beyond through the papacy? Was he trying to heal the wounds made by rebellious popes from the 650s? All these questions would be answered if only more papal letters survived...",
"Of the lost works of Archimedes of Syracuse that we know about, the most intriguing to me is *On Sphere-Making*, mentioned in Book VIII of the *Collection* by Pappus of Alexandria (see Chapter 3 in S. Cuomo, *Pappus of Alexandria and the Mathematics of Late Antiquity*). This apparently contains a description of a miniature planetarium Archimedes built, \"a sphere constructed so as to imitate the motions of the sun, the moon, and the five planets in the heavens.\" (Heath, *[The Works of Archimedes](_URL_1_)*, p. xxi). \n\nHere is an excerpt from a description, from Cicero's *De Re Publica*, of a device which he says was Archimedes' \"sphere\" (source and commentary [here](_URL_2_)):\n > But when Gallus began to give a very learned explanation of the device, I concluded that the famous Sicilian had been endowed with greater genius than one would imagine it possible for a human being to possess. [...] this newer kind of\nglobe, he said, on which were delineated the motions of the sun and moon and of those five stars which are called wanderers [the five visible planets], or, as we might say, rovers, contained more than could be shown on the solid globe, and the invention of Archimedes deserved special admiration because he had thought out a way to represent accurately by a single device for turning the globe those various and divergent movements with their different rates of speed.\n\nIt's likely that the contents would bring us some clarity on the mysteries surrounding the [Antikythera mechanism](_URL_3_).\n\nSpeaking of Archimedes and lost works, Johan Heiberg's discovery of the [Archimedes palimpsest](_URL_0_) is an extraordinary lost-and-found story. The codex contains several works by Archimedes, some of which were previously thought to be lost, hidden under a 13-th century Christian religious text. \n\n",
"Although a lot of the data has been published so I can't be too upset, the sheer pointlessness of the destruction of the [Nemi ships](_URL_0_) still gets to me. It is also a little frustrating that there is no real certainty over who was to blame, although to be frank the Allies' explanation always struck me as a little mustache-twirly.",
"I deal with formerly classified documents pretty much every day. Government secrecy makes the terms \"missing\" and \"destroyed\" a little tricky to use, because they may be effectively missing and destroyed to most historians, but in reality they are often just being denied to us. Some secret documents do go missing, however, because they get misplaced or misfiled within the gargantuan government bureaucracy that at one point was trying to keep them secret, even if they no longer contain secret information in them. In fact, when it comes to secret documents, being misplaced is more common than being destroyed, because legally you cannot detroy secret documents without leaving a large paper trail — so that means that the documents are usually preserved, _if_ anyone can figure out where they are preserved.\n\nAnyway, on my blog not too long ago I wrote a series of very long posts about my hunt for, eventually success at finding (through unorthodox archival practice), and frustrations with declassification, regarding the legendary unredacted copies of the security hearing of J. Robert Oppenheimer. [Here is the link to part I](_URL_1_), where I describe why I started looking for them and how I found them. [Here is the link to part II](_URL_0_), where I analyze the new transcripts for what they do (and don't) tell us about the Oppenheimer case.\n\nSeparately, a few years back [I wrote about a case where the US government \"lost\" about 4 million pages of secrets](_URL_2_) through misfiling. It happens more often than one might think, if one thought (erroneously) that the US government was very good at keeping track of large amounts of historical paperwork (it is not).",
"i do a lot of work in the history of islam in america and we lack a ton of valuable documents for most groups that started before 1950, especially african american groups.\n\nI'd say some of the biggest things that scholars would want are:\n\nA) any writings connected to W.D. Fard, the founder of the Nation of Islam (a few of his supposed letters are circulating, though). I think number one on his list would be a book that police found and that was supposedly written by him, entitled \"the bible of islamism\". Also, it would be great if any of the supposedly hundreds of letters written TO him that the police found came up one day. Karl Evanzz supposedly got the Detroit field office FBI file on the NOI which supposedly had details that no other document contained, including info from the local police's files after they arrested original members. However, evanzz gave his papers to Howard Univ, and when I made a request for the Detroit file, they couldn't find it in the collection.\n\nB) documents related to other early black groups such as Satti Majid's Moslem Welfare Society and Abdul Hamid Suleiman's Canaanite Temple (and of course Noble Drew Ali's 1913 Moorish Temple). Of particular value would be the State Department records of the 1922 Shriner push to have Suleiman investigated. Unfortunately, the State Dept says they can't find it. \n\nOther than that, I am proud to say that I recently discovered a document, tucked away in an extremely rare microfilm collection, that no one ever had any idea existed before: A letter used for organizing the very first Sufi group in the US (pre-Inayat Khan)--and perhaps the first Sufi group for ANY modern white europeans/americans ",
" > As an archivist, it pains me to admit this, but sometimes humanity’s records don’t survive.\n\nMy reasoning for suggesting this topic is was to talk about an instance where missing documents can actually be a good thing, in some sense.\n\nI'm talking about the mountains of documents about Chinese immigration which were destroyed during the 1906 San Francisco Earthquake. On the one hand, these documents would have been invaluable resources for quantitative historical research on early China-to-U.S. immigration of Chinese people. However, the destruction of the documents made life easier for a lot of Chinese people.\n\nSince corroborating documents were all destroyed, Chinese people living in the U.S. that claimed to be natural citizens essentially had to be taken at their world by the federal government. While I can't find an academic citation for this number, I've heard it claimed that if everyone who came forward as a natural citizen actually was, it would have required every Chinese woman to give birth to 800 people. At any rate, it was a widespread phenomenon, allowing Chinese immigrants the ability to secure a lot more rights, all possible only because of the destruction of a massive stack of documents.\n\nThis all had a trickle-down effect to--with so many Chinese claiming natural citizenship, they were then able to import their children. Oftentimes these didn't end up actually being \"their\" children, I've written on the 'paper sons' phenomenon before. The gist is that Chinese-American citizens would sell native Chinese children the right to claim they were the Chinese-American person's children, and thus have a chance at immigrating to the U.S. that way.\n\nLord knows how many fewer Chinese citizens the U.S. would have had in the early 20th Century if it hadn't been for that fateful destruction during the 1906 San Francisco earthquake.",
"For many documents in my field, it was not that they have been lost, but they were never recovered in the first place. Many African-American newspapers were never saved beyond a few years past their original publication date and thus major sources of ethnic communities have been lost. In addition to seemingly simple sources of history such as newspapers, the whole of African-American history is being tainted by a lack of primary sources, oral interviews are hard to come by (in part due to the traumatic events associated with their communities) and the problems with literacy that were endemic early on leave few letters and diaries in some areas. One thing that actually comes to mind where an important series of artifacts being saved was the donation of the [Richard Samuel Roberts photographic plates](_URL_0_) to the University of South Carolina. Roberts was an African-American photographer in the 1920's and 30's specializing in photographing African-American people and society. After his death, all the remaining glass plates were placed under the house for saving. It was not until the late 1970's that researchers were able to locate and preserve the plates, as well as reprint them in their entirety, has conditions been slightly different, or it had taken longer to recover, these important images would've been lost. ",
"The most important letter signed by Soekarno, dubbed Supersemar (Surat Peritah Sebelas Maret) or the March 11^th Command Letter that gave birth to New Order and ended the era of Soekarno is... not really lost, but there are three different versions that are being kept in National Archive right now, and are believe to be [fake.](_URL_0_)\n\nFirst version was issued by the Secretary with Garuda letterhead, was short and to the point. \n\nThe second was issued by the Army with Garuda letterhead, stating Soeharto as Revolution General and added one more command while embellishing the first command. \n\nThe third doesn't have any letterhead whatsoever or any information who issued it, and Soekarno's sign is also slightly different than the other two. \n\nPresident's formal letterhead should be stars with cotton and rice-paddy and not Garuda.\n\nThe letter supposedly gave all the rights for Soeharto, our second president, to take any means necessary to quell the dire situations pasca Indonesian Communist Party riot and subsequent purge. \n\nSoeharto then used this letter as justification for massacring Communist Party members and every person who had ever donated money to the party (mostly Chinese - Indonesian), executed fifteen Soekarno's loyalist generals, and suppressed media's news report at the time. \n\nA year later, Soeharto became President without election. "
]
}
|
[] |
[
"http://www.reddit.com/r/AskHistorians/wiki/features/trivia"
] |
[
[],
[],
[
"http://www.chicagoreader.com/chicago/the-late-great-municipal-reference-library/Content?oid=887378"
],
[
"https://www.worldcat.org/title/capturing-the-light-the-birth-of-photography-a-true-story-of-genius-and-rivalry/oclc/827256979&referer=brief_results"
],
[],
[],
[
"http://archimedespalimpsest.org/about/",
"https://archive.org/details/worksofarchimede029517mbp",
"http://hist.science.online.fr/antikythera/DOCS/THE%20PLANETARIUM%20OF%20ARCHIMEDES.pdf",
"http://www.antikythera-mechanism.gr/project/overview"
],
[
"http://en.wikipedia.org/wiki/Nemi_ships"
],
[
"http://blog.nuclearsecrecy.com/2015/01/16/oppenheimer-unredacted-part-ii/",
"http://blog.nuclearsecrecy.com/2015/01/09/oppenheimer-unredacted-part-i/",
"http://blog.nuclearsecrecy.com/2012/05/07/missing-four-million-pages-of-secrets/"
],
[],
[],
[
"http://www.columbiamuseum.org/exhibitions/ourtime-ourplace/"
],
[
"http://upload.wikimedia.org/wikipedia/commons/8/89/Supersemar2.jpg"
]
] |
|
319yt6
|
To what extent was the Japanese government aware of the Manhattan project or similar nuclear weapons project prior to the deployment of the nuclear bombs during WWII? Was there any awareness that such a thing was possible?
|
Basically - Did the Japanese have any idea that the Americans were working on a superweapon project? For that matter, did the Russians or the Germans? Was there an understanding among world governments that such a thing might be possible or was it completely unexpected?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/319yt6/to_what_extent_was_the_japanese_government_aware/
|
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"Practically all physicists knew that atomic bombs were theoretically possible after the discovery of nuclear fission and the nuclear chain reaction in the early months of 1939. Most thought that they were a technology that was not going to emerge for another decade or so, and if they were interested in chain reactions, they focused on the possibility of using them to generate power, which is a much easier problem than that of a bomb. The idea of atomic bombs had been \"in the air\" in a general, science-fiction sense since 1914, but certainly by 1939 they were a common trope in \"gee whiz\" newspaper and magazine stories. When fission was discovered there was plenty of press about its possibilities, though, again, scientists had long grown skeptical about the idea of being able to release atomic energy on an industrial or military scale, because most of the discussion of it had been uninformed nonsense, and there were many technical factors that were still unknown (and, had nature differed in tiny, almost imperceptible ways, would make such weapons impossible, or at least unlikely in the near term). \n\nThe Japanese had a small nuclear project that looked into both of these possibilities. So they were aware of the theoretical potentials, though they also recognized that to develop even the power option would require creating an entirely new industry from scratch, and involve a lot of risk, and that developing a weapons option would be even more difficult.\n\nAs for specific awareness of an Allied projects, there is no evidence that anyone in Japan considered it a real issue. The Japanese scientists concluded that even the Americans would have a tough time of making a nuclear weapon. (They were right — it wasn't easy.) They seem to have made no serious effort to find out whether it was true, however. If they had, I suspect they would have quickly figured out that the United States was expending vast resources on the subject — there was a lot of evidence in plain sight, in the form of leaks and mysterious disappearances (all of the nuclear physicists stopped publishing, for example). But Japanese intelligence in the US mainland was terrible, on the whole, so I tend to just chalk up this lacunae to that fact. \n\nI have never found any evidence that the Germans had much of an indication of the American bomb project either. [I have written on this question a bit here](_URL_0_). Basically, from what sources I have available to me (which are not complete, to be sure), it seems the Germans believed that they were far ahead of the Americans with regards to fission research. They did send information to German spies asking them to look into the question but the very questions they asked indicated that they thought it was small-scale and probably not very sophisticated. (The spies were immediately caught — the Germans also had poor intelligence in the mainland USA.) \n\nThe Soviets are a different story. They had indirect indications of an American bomb project — they noticed that the people who were working on fission right before the war suddenly vanished — and they also had volunteer spies (moles) in both the UK and US portions of the fission work. They had an extensive overview of the project as well as knowledge of many specific technical details as a result, from very early on. So it was not unexpected at all for them.\n\nAs for other countries, one of my favorite episodes is when a group of Indian physicists showed up to the United States during the war and started asking around to find out where the uranium was being enriched. The Manhattan Project security people quickly found them and asked them where they had gotten such an idea. The Indians (quite indignant about being interrogated) told them it was obvious to any competent physicist that this was something the United States must be doing. They were told to stop asking questions and released. "
]
}
|
[] |
[] |
[
[
"http://blog.nuclearsecrecy.com/2013/09/13/what-did-the-nazis-know-about-the-manhattan-project/"
]
] |
|
mrfm6
|
What causes absorption of right- or left- circularly polarized light by chiral molecules?
|
I am trying to understand this and having a hell of a hard time. Specifically, infrared radiation for Vibrational Circular Dichroism. I understand the principles of light absorption and re-emission, but I can't pin down why a chiral molecule would preferentially absorb one type of circularly polarized light and not the other.
Here's what I have so far:
1- Circularly polarized light is just 2 "plane waves" rotated 90 degrees and offset by pi/2 wavelengths.
2-Certain molecules can absorb an re-emit light, causing a delay in that light which we see as a change in the speed within that material defined by the refractive index. This delay causes the pi/2 shift between plane waves to become offset and the ellipticity of the light increases.
3-Chiral molecules absorb right- and left-circularly polarized light differently. This is where I lose it.
Why?? Both types of molecules have a set of vectors that define their vibrations, what is it about chirality that is so different?
Thank you in advance for your responses.
|
askscience
|
http://www.reddit.com/r/askscience/comments/mrfm6/what_causes_absorption_of_right_or_left/
|
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"The difference between molecules of left and right chirality is exactly the same as the difference between left and right circularly polarized light- a mirror symmetry.\n\nThe reason that a non-chiral molecule cannot reflect the two polarizations differently is because that molecule has a mirror symmetry- it remains the same if we mirror it. If we take the scattering of the left-handed light and mirror it, we get the scattering of the right-handed light. Since the physical interaction (electromagnetism) obeys mirror symmetry, this tells us that the amplitude for scattering left-handed and right-handed light is the same.\n\nBut this isn't true for a chiral molecule- if we take the picture of a left-chiral molecule scattering left-handed light, and mirror it, we get the picture of a right-chiral molecule scattering right-handed light. Mirror symmetry says that those two things should be the same. Similarly, the amplitude for left-chiral molecules to scatter right-handed light should be the same as the amplitude for right-chiral molecules to scatter left-handed light.\n",
"The answer lies in the polarized nature of the electric and magnetic fields induced by the light. Polarized light, like all light, will induce magnetic and electric dipoles within the matter it interacts with. These induced dipoles are distortions of the electron clouds around the molecule, and can thus be seen by looking at the absorbance spectra of chiral molecules using polarized light.\n\nSo polarized light will preferentially induce a directional dipole (probably poor language) in the molecule. Because of their chiral nature, chiral molecules have unique dipole moments that lead to absorption.",
"The difference between molecules of left and right chirality is exactly the same as the difference between left and right circularly polarized light- a mirror symmetry.\n\nThe reason that a non-chiral molecule cannot reflect the two polarizations differently is because that molecule has a mirror symmetry- it remains the same if we mirror it. If we take the scattering of the left-handed light and mirror it, we get the scattering of the right-handed light. Since the physical interaction (electromagnetism) obeys mirror symmetry, this tells us that the amplitude for scattering left-handed and right-handed light is the same.\n\nBut this isn't true for a chiral molecule- if we take the picture of a left-chiral molecule scattering left-handed light, and mirror it, we get the picture of a right-chiral molecule scattering right-handed light. Mirror symmetry says that those two things should be the same. Similarly, the amplitude for left-chiral molecules to scatter right-handed light should be the same as the amplitude for right-chiral molecules to scatter left-handed light.\n",
"The answer lies in the polarized nature of the electric and magnetic fields induced by the light. Polarized light, like all light, will induce magnetic and electric dipoles within the matter it interacts with. These induced dipoles are distortions of the electron clouds around the molecule, and can thus be seen by looking at the absorbance spectra of chiral molecules using polarized light.\n\nSo polarized light will preferentially induce a directional dipole (probably poor language) in the molecule. Because of their chiral nature, chiral molecules have unique dipole moments that lead to absorption."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
a9a2rj
|
[META] Merry (UTC) Christmas and Happy Holidays to AskHistorians! As an extra-special gift from the Asia flairs, we've completely revamped our book recommendation list! Links below!
|
The title has quite obviously given away the point of this post, which is to announce our shiny, new and improved Asia book list! Over the course of the past four months, the flair panel has been collaborating on creating a new list to take advantage both of the expertise of the current panel and certain features of the platform which we had not previously made use of, and now we are done! The old lists have since been relegated to a legacy section (links to these will be found at the end of both this post and each of the new booklist pages), and in their place we have new lists of recommendations for numerous areas of East Asian, Central and Himalayan, and South and Southeast Asian history, with 158 books in all!
Before I link to them, though…
### What’s changed?
**Flairtext:** This is the biggest and most obvious change. One especially nice feature of Reddit’s formatting is that, with a little wizardry, you can use flair text in posts, comments and wiki pages, which, in the case of this sub, means we have been able to introduce a system of [colour](#flair-northamerica) [coded](#flair-africa) [tagging](#flair-europe). Each entry on the list now has at least two tags – difficulty and category.
1. The difficulty tag marks out the level of complexity, specialisation and necessary background knowledge, and can be:
1. [Entry-Level](#flair-africa) – Relatively easy to get into especially for a lay audience.
1. [Intermediate](#flair-southamerica) – Still not hard to get into but with a little more complexity at the conceptual level.
1. [Advanced](#flair-northamerica) – Mainly aimed at a more academic audience.
1. [PhD-Level](#flair-archaeology) – Definitely for academic purposes.
2. The category tag(s) indicate the content areas the book covers, and can include any number of the following self-explanatory categories:
1. [Overview/General](#flair-skedaddlespecial)
1. [Political](#flair-europe)
1. [Social](#flair-art)
1. [Economic](#flair-middleeast)
1. [Cultural](#flair-moderator)
1. [Religious](#flair-religion)
1. [Military](#flair-military)
1. [Primary Source(s)](#flair-qualitycontributor)
1. [Other – (please specify)](#flair-technology)
**Slightly more information:** While our old entries always had authors and usually had publication dates, we’ve made sure to include date of publication and ISBN-13 numbers for all publications just to make searches on external sites a little easier. Additionally, we’ve tried to make sure that all the mini-reviews have a reasonable level of detail and to include the recommending flair’s handle at the end. This will help if a user wants to ask for further information on a particular recommendation.
**Revamped regions and periodisation:** Thanks to the absolutely brilliant variety of flairs we have, the old periodisation has proven a little overly simple. The periods covered for each region have generally been increased, and indeed we’ve added a couple of extra regional categories for Taiwan and Hong Kong (for obviously objective, neutral and non-ideological reasons) as well as regrouped Southeast Asia somewhat.
**Amazon affiliate links:** Whilst affiliate links have always been part of the booklist, some entries may link straight to Amazon. Thanks to the tireless work of /u/Georgy_K_Zhukov we’ve been able to ensure that all the entries on this list have proper affiliate links, so you can feel no guilt at all with your post-Christmas shopping.
**Some collateral damage:** Unfortunately, due to some old flairs with expertise in certain areas having since left the panel or been unable to contribute due to real life rearing its ugly head, a few areas that were comparatively well-covered (Japan, Korea and Mongolia especially) have been much reduced in terms of entries for the time being. Not to worry, though: these new lists are by no means final and will no doubt be updated over time as the flair panel finds more books to recommend and welcomes new members to the team, and as mentioned at the beginning the old lists will still be linked to at the bottom of the new ones if there’s an area you’re interested in that has received poor coverage.
But enough about the changes. Now for the lists themselves!
### The New Lists
**[East Asia](_URL_7_)**
**[South and Southeast Asia](_URL_1_)**
**[Central Asia and the Himalayas](_URL_0_)**
### Thanks and Acknowledgements
As Reddit doesn’t let you tag more than 3 users in a post, I will put these in a series of comments below just so everyone who was involved is aware.
### Statistics
Just for fun, I made spreadsheets to keep track of progress, and I made some charts with them! Below are charts for East Asia, South and Southeast Asia, Central Asia and the whole list, showing the distribution of regions of coverage, difficulty ratings, dates of publication and categories covered. (Please note that yes, there is no consistent scale on the bar charts, as the number of books in each region and the spread of categories varied heavily and I wanted to show the detail well.)
**[East Asia](_URL_8_)**
**[South and Southeast Asia](_URL_2_)**
**[Central Asia and Himalayas](_URL_9_)**
**[Full List](_URL_3_)**
Just to make a few observations on this data:
* We’re pretty up to date, with the majority of recommendations being from the past two decades and just under 25% published before 1990.
* We’ve generally got a good amount of breadth in terms of categories, albeit with a general lack of economic history in general, East Asian religious history and Central Asian social history. Something for future flairs, perhaps?
* In terms of difficulties we’ve got a reasonable spread. Obviously PhD-level stuff is in the minority, but we’ve got a reasonable spread of difficulties on the whole.
And finally some trivia:
* The most heavily covered region in the booklist is undoubtedly China with 55 books (59 if we include Taiwan and Hong Kong), making it just over a third of the list as a whole.
* The most heavily covered subcategory is Late Imperial China with 29 entries, just ahead of pre-colonial Southeast Asia with 27 (if we combine the mainland and maritime regions.)
* 7 entries are anthologies, either as single volumes or series.
* The most recommended author is M. C. Ricklefs, 6 of whose books are included in the Southeast Asia section.
### Penultimate Word
So, there you have it! We hope you have a great holiday season and we hope the recommendations are useful!
### Legacy Lists
**[East Asia](_URL_4_)**
**[South and Southeast Asia](_URL_1_legacy)**
**[Central Asia and the Himalayas](_URL_0_legacy)**
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/a9a2rj/meta_merry_utc_christmas_and_happy_holidays_to/
|
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"Now we get to the comments thanking the contributors to the list. Firstly, I’d like to give special thanks to three flairs whose contributions are not (at present) immediately apparent on the list itself.\n\n* Firstly I’d like to thank fellow Asia flairs /u/keyilan [Moderator | Historical Linguistics | Languages of Asia](#flair-moderator) and /u/NientedeNada [Late Edo Period | Meiji Restoration](#flair-asia), who were of great help during the initial planning phases in terms of deciding upon what changes to make, from broader issues like the extent of the rewrite to more minute issues of formatting.\n* I’d like to again thank /u/Georgy_K_Zhukov [Moderator | Post-Napoleonic Warfare & Small Arms | Dueling](#flair-moderator) for taking the time to add affiliate links to the doc, as well as more generally for being such a great mod and such a prominent presence on this sub. Rock on, Georgy!",
"I'm glad this is out! So will we be able to add more entries to this? ",
"Heads up, the links appear to be in edit mode. Reddit gives me a permission error when I try to view the lists. ",
"Thank you for this! Really excited to read some of these and appreciate the hard work you guys put in! ",
"Looks like a great list, I cant wait to dig into the books. Thanks to all the flairs and folks who put in the work to make it."
]
}
|
[] |
[
"https://www.reddit.com/r/AskHistorians/wiki/books/innerasia",
"https://www.reddit.com/r/AskHistorians/wiki/books/southasia",
"https://imgur.com/V1vAZI6",
"https://imgur.com/hnjlBTj",
"https://www.reddit.com/r/AskHistorians/wiki/books/eastasialegacy",
"https://www.reddit.com/r/AskHistorians/wiki/books/southasialegacy",
"https://www.reddit.com/r/AskHistorians/wiki/books/innerasialegacy",
"https://www.reddit.com/r/AskHistorians/wiki/books/eastasia",
"https://imgur.com/E5Y8IWa",
"https://imgur.com/y2X2MoP"
] |
[
[],
[],
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] |
|
2yesv7
|
does piracy actually hurt the profit of corporations?
|
I'm going to assume you all the know the normal arguments from both sides. But is there any hard data on this subject?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2yesv7/eli5does_piracy_actually_hurt_the_profit_of/
|
{
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"If any brainy person with data can answer this well, I hope they also take into consideration the affect of franchise knock-on, which is often not discussed. And arguably makes up a larger long term profit and vertical integration, or market synergy and all that.\n\n\n\n\nFor example people who may pirate a show still love the show and thus buy shirts and toys and the Happy Meal. So missing out on 3 dollars for ad views is nothing compared to the $300 collected from the new Fan."
]
}
|
[] |
[] |
[
[]
] |
|
44tvzf
|
Why does male pattern baldness follow the pattern it does? i.e. from the top of the head down, often in a perfectly straight circle around the head.
|
I'll be more specific. Why for example does it not start from the collar and work up leaving an island on the top? Or why not just the sides leaving a Mohawk? It's some variation of mid-line top then down. It always ends up in a horseshoe around the head.
|
askscience
|
https://www.reddit.com/r/askscience/comments/44tvzf/why_does_male_pattern_baldness_follow_the_pattern/
|
{
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"It doesn't. Sometimes the hair line recedes all the way to the back of the head, sometimes a bald spot appears on top of the head and increases in diameter over time. \n\nSometimes there is even a patch at the front that is missed leaving a little island of hair. \n\n\n_URL_0_",
"So it's well knows that male pattern hair loss is due to dht which is the highly potent version of testosterone which is a steroid promoting tissue growth. Ok anyway dht is known to cause thinning of the follicle. There is a theory on the specific pattern and it's called the gravity theory... Goes like this... As men age there is decreased fat in the face and scalp hence less support and the areas that tend to bald are the areas that have the most gravitational pull leading to damage. The damage then requires testosterone for repair leading to a buildup of DHT in the area... Bada Bing bada boom. Of course this is thought to prove but it is absolutely a fact that there is a buildup of DHT in the balding areas compared to the spared areas."
]
}
|
[] |
[] |
[
[
"https://media.licdn.com/mpr/mpr/shrinknp_800_800/AAEAAQAAAAAAAAaiAAAAJGE1MGYzZjRlLWQyYWItNDc5Ny1hNzAwLTI1N2U5OTQwMDEzOQ.png"
],
[]
] |
|
7pxblx
|
how did some neighborhoods in america came to be known as 'black neighborhoods'? is it mainly because of segregation?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7pxblx/eli5_how_did_some_neighborhoods_in_america_came/
|
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"Housing segregation enforced by redlining and blockbusting and white flight. \n\nSo, you take a neighborhood, and you line it. Red lines are where black people are able to live. Banks would (and still do) deny black people loans to live outside of the red lines, and designate the loans inside of the red lines high risk. Certain towns would also have housing contracts that said that black people weren't able to live there and that no one would sell their houses to a black family. At the same time, one white family moves out of a white neighborhood, and the house is sold to a black family. The other families then leave because black people bring down property values, thus making that neighborhood a red lined one. \n\n\nThere's a good article about Chicago here:\n _URL_0_",
"Both official and unofficial segregation, yes, and some of it still ongoing.\n\nTravel in, say, Texas. You'll see lots of little towns that are directly adjacent to or even entirely surrounded by bigger towns and don't seem to have much reason to exist as separate entities. They were often created to either be white- or black-only (usually white-only). This was enforced by things like deed restrictions (you agree not to sell your property to a non-white family), and unofficially by threats of violence or what-have-you.\n\nRead deed restrictions or HOA documents from the 40's and 50's. They often have explicit restrictions on the race of the property owner.\n\nAlabama went all the way to the Supreme Court for the right to re-draw city boundaries so that in a given city there were mostly white people or whatever, and the way Alabama's government works, city boundaries can be redrawn from the state government almost arbitrarily and cities are very limited in what laws they can pass themselves. This centralization of power in the state government was done immediately after the Civil War for the explicit purpose of making sure the state could divide itself into white and black cities and then deny black cities the power to pass their own laws.\n\nBefore various pieces of legislation (the Civil Rights Acts, the Fair Housing Act, and so on), it was more-or-less legal for banks to deny mortgages to black families who wanted to buy houses in white neighborhoods -- and banks would do so to keep their white customers happy. Even after it was made illegal, Realtors would intentionally not show houses in white neighborhoods to black families, and discourage white families from buying in black neighborhoods.\n\nWhen that was made illegal, Realtors would make sure to include photos of the family or photos of family photos, when photographing the house for sale, to be sure people knew that they were looking at houses in black neighborhoods.\n\nNow that sort of thing is illegal too, and it is getting better, but there's an immense amount of inertia in things like that. Houses aren't movable, and because of their inherent value tend to stay in families for more than one generation more so than other kinds of property. Because the older generation lives where they do and children often want to live near their families when they buy a house, the network effect acts as pressure to keep neighborhood demographics more stable than they might otherwise be.\n\n(Of course that doesn't mean that they *always* stay that way, just that they're slower to change than the demographics of other things like, say, Universities or apartment complexes, which are more flexible.)\n\nBecause of the relative demographic stability of neighborhoods, they're often a pathway to other unofficial racism. School district lines are drawn such that schools are tilted more heavily towards one ethnicity or another, and schools in black neighborhoods are often underfunded. Other city services are often neglected, and so on.\n\n(In 2018 there are still hundreds of court-mandated desegregation orders for school districts, some renewed as recently as 2017, because of cities and school districts maintaining de facto segregation by drawing boundary lines in certain ways. I remember growing up in small-town Texas. We had two high schools for a town of only 12,000 people. Even though the city was 40% black, one high school was 99% white, less than a mile away from the other. I graduated in 1998.)\n\n(Speaking from personal experience, there was a neighborhood here in Austin, in the middle of town, that was still on septic systems. The demographics were mostly black and Hispanic. The city promised to get sewer service to them by 2009. It took until 2016. They promised sidewalks back in 2008...still very few sidewalks. This was all explained as \"not enough money in the budget\" -- but whiter parts of town got new bicycle paths, city-owned bicycle repair stations, covered bus stops, etc, etc, during the same time period when people in this neighborhood were getting their homes condemned because their septic systems were failing and they didn't want to spend $20,000 to fix it just to have to pay more to hook up to the sewer when it finally came in.)",
"Covenants were a biggy. There'd be covenants on houses saying you can't sell the house to a non-white person. Those were made illegal (or invalidated) but if you look at some older homes the covenant is still there, it just can't be enforced.\n\nSo black people and other minorities (California is one of the most segregated states if you count in Hispanic, just black and white and NY is the most segregated. The south was actually forced to integrate while the north just got to be racist) couldn't buy homes in certain neighborhoods leading them to find homes where they could buy. Overtime it becomes cultural and people like to stay close to home.",
"Part segregation, part economic, part social.\n\nIn housing, segregation was very real, but usually could not be enforced by laws. Instead, banks and realtors would strongly discourage black families from moving into the \"wrong\" neighborhood, and white neighbors would be less than welcoming. Even if you weren't a racist, the fact other racists wouldn't want to live in a mixed neighborhood meant your property values went down, so you might not be thrilled at the prospect either. \n\nAt the same time, working and middle-class blacks were often able to build decent communities in the neighborhoods that already were mixed. A new black family might not be terribly interested in the hassle around living in a white neighborhood, especially if it were more expensive. You also have cultural affinities. Even if segregation was not present, you would expect certain neighborhoods to develop cultural trappings, like food and music, that made it more desirable to people of that culture.\n\n"
]
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"https://www.architectural-review.com/rethink/archive/white-flight-red-lining-block-busting-and-panic-peddling/8685447.article"
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||
xji30
|
why were african, australian and native american civilisations so technologically inferior compared to european and east asian civilisations?
|
Thanks for the answers Reddit, most of them tell me to read "Guns, Germs and Steel" which I'll definitely buy once my exams are over.
So to summarise:
* Similar climate encouraged trade of farming techs/animals etc.
* Domesticated animals
* Close proximity of groups of people encouraged competition and a military tech arms race
* Longer life spans due to colder climate/less mosquitoes (makes sense, malaria is thought to be the number one killer in history when it comes to diseases)
* Less disease allowed large groups of people to live together, allow specialisation in particular jobs
As mentioned by hippiechan some civilizations (yes I spelt it wrong twice in the title :(, also brackets and smileys don't work _URL_0_) in the Americas (Aztecs, Mayans, Incas etc.) and Africa were technologically advanced (thought not to the same level of weaponry) its just that they were wiped out fairly quickly during European expansion by guns and disease.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/xji30/why_were_african_australian_and_native_american/
|
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"There are two main explanations. The first is that these places were much more isolated. Traders didn't come over as often (or ever), and so any technological advancements didn't get shared like they did in Europe. So they had to invent everything themselves, while Europeans could steal liberally from the people they traded with.\n\nThe second is a bit trickier. It's the navigable-rivers-through-arable-land theory. Navigable rivers can ship lots of goods cheaply, and arable land means that it's cheap to run cities on these rivers. Europe has a lot of arable land with very good coverage with navigable river, so it's a lot easier to make manufacturing wealth there.",
"For one thing, it's cold enough in East Asia and Europe (note they're at similar latitudes) for germs to die every winter, so people live longer and technology can advance accordingly. In the case of Australia, humans inhabited the continent and killed off all the big game before they domesticated anything, so they didn't have the advantage of cows and horses. In Africa, in order to avoid diseases carried by mosquitoes, people traditionally lived in small communities far from water sources, meaning they have to put in a lot of effort to carting water. This means that they lacked the benefits of a city like job specializations, etc. \n\n[\"Guns, Germs and Steel\"](_URL_1_) is a really interesting read to answer this question more fully.\n\n[There was a Cracked article](_URL_0_) that made me think we don't get the whole story about Native Americans. Supposedly they were very advanced, but a plague wiped them out and allowed Europeans to conquer them.",
"There's a great book that covers this exact topic, the propagation of civilizations and technology in general, but it talks about why parts of africa, australia, and the america's lagged behind europe and asia. It's called [Guns, Germs, and Steel](_URL_0_). \n",
"I answered this in my explanation of why Africa is so fucked up currently, let me repost it for you:\n\nIn Europe, the English, French, Germans, etc... all were in close proximity of one another and had to compete for resources. That's why the military of Europe evolved so fast. They had to be the best of the best to win resources, while Africa is so spacious and devoid of the same resources, especially in the center where its all desert.\nWhen you look at resources available to the Africans versus say, the Europeans or Chinese its easiest to see how successful a society has been based upon their access to key domesticated plants and animals. Almost all of Europe and most of China is suitable for raising animals like pigs, chickens, cows, horses, sheep and other traditional farm animals as well as edible plants like wheat, beans, and apples. These animals and plants are key parts of diets to make sure people get enough essential vitamins and minerals, as well as being staples of the military for hundreds of years. In Africa, the climate is not so suitable for raising the animals that Europe and China had access to, as well as having an abundance of animals that aren't able to be domesticated or take far too long to be useful like lions, elephants, or the African buffalo.\nAdditionally, it has been noted that technology and domesticated animals are easily transferable along the same longitude as all areas along this will have nearly the same climate. Plants and animals that are successful in say, Germany, will most likely be successful in France, Russia, or the United States since they are pretty close to the same longitude. Many of these staple animals from Europe had been brought to Africa when they had been colonized prior to the Berlin Conference, and most were not successful. Animals, plants, and even people died fairly quickly to coming to Africa.",
"Africa had a lot of advanced civilisations in the past, the Egyptians for a fucking start. So did South Asia. The Native American empire was also quite strong and actually defeated the Vikings in their attempts to settle America, they got wiped out by disease. Read up on history a little, jesus.\n\nThe world did not begin only like 200 years ago you know....",
"Several reasons. Mainly:\n\n* Africa and the Americas are longer north-south, while Eurasia stretches east-west. This makes it easier for cultural innovation to spread in Eurasia, because climate differences are less drastic. Agricultural techniques that work in Canada aren't likely to work in Mexico, but techniques that work in East Asia can work in Europe. Plus it's just easier to travel when climate differences along your route aren't so drastic, and easier travel means more trade and more exchange of ideas. Easier spread of new ideas means civilization advances faster.\n\n* Africa is home to a particularly harsh climate if you're from the northern hemisphere, as well as lots of tropical diseases, which makes it unwelcoming for traders from Eurasia, or sometimes even from other parts of Africa. Again, this cuts down on the spread of new ideas.\n\n* Domesticable plants and animals. Not all plants and animals are equally easy to domesticate; for instance, there's a reason we have domestic sheep and not domestic deer - sheep instinctively bunch together when startled, making them easy to herd, while deer scatter. Similarly, all serious attempts to tame zebras have failed. As it happens, Eurasia has lots of useful crops and animals that are relatively easy to domesticate. The Americas and Africa and Australia, not so much. (The absence of the horse from the Americas and Australia, in particular, is a serious disadvantage.)\n\n* Don't forget that humans didn't arrive and settle down in the Americas ~~and Australia~~ until much later than pretty much anywhere else, so sedentary civilizations in the rest of the world had had a lot more time to develop.\n\nIt's also worth realizing that mainstream education as a general rule tends to downplay the achievements of American, Australian and African civilizations, as they weren't seen as really worth studying by Western scholars until quite recently. This does *not* mean they weren't technologically inferior at the point of contact, but they were a bit more technologically advanced than people generally tend to assume.",
"I believe its because of the balance of power in Europe, they had lots of kingdoms in a small area, each one powerful enough to defend itself but not able to overpower the others.\n\nthat means every kingdom would be constantly looking for ways to get ahead of the neighbors, by developing trade and finance, techology, funding expeditions for resources, etc.",
"*Guns, Germs, and Steel*. Not exactly 5 year old reading material, but it will answer any and all questions on the matter.",
"Randomness, luck. There are a billion reasons that cause technology to advance and a billion reasons that cause it not to. It's just that when you draw the line and add all of them up, some place happens to come up ahead of the other. ",
"They weren't.\n\nWe view European and East Asian civilizations as being 'more advanced' because of our views of advancement, which typically revolve around art, science, written literature, human rights, etc. As such, we view the Roman Empire as being very advanced for it's time because it was large, organized around a well-defined political system, and had widespread influence over arts and culture. We consider the Tang Dynasty to be among the greatest of Chinese dynasties because of the art, culture, and religion that came out of it.\n\nThen there are the so-called \"technologically inferior\" societies, such as those in the Americas, Australia, and Africa. In Africa, Egyptian civilization was creating great leaps in science, art, and mathematics before the Classical Era in Greece, and the Mali empire in the 13th century was home to Timbuktu, an educational center for the medieval world. Australia, admittedly, didn't have much in terms of great civilizations, but New Zealand and the pacific had the Maori and many Polynesian groups, which combined made great marvels of architecture, art, and seafaring.\n\nIn North America, the civilizations were on par with Europe at least by the 12th century. The Maya civilization in Central America had advanced understandings of astronomy and space, and were able to accurately predict solar eclipses using mathematics. The Inca civilization of South America are known for their greatest marvel, Machu Picchu, to this very day, which is an architectural and mathematical masterpiece. In North America, the Iroquois people of what is now New York/Ontario had an advanced governmental system, and their culture was actually more liberal towards women upon their first contact with Europeans.\n\nThe notion that these civilizations were 'less technologically advanced' only comes from the idea of technological advancement, which at the time of many of their discoveries, meant military capability. Civilizations in the America's struggled to fight off the influx of Europeans because they had more advanced weaponry (and the fever which wiped out 90% of the indigenous population). African civilizations are seen as less advanced because the people themselves were kidnapped and used as slaves for hundreds of years, and how advanced can a civilization be when it's made up of potential new property?",
"High technology isn't developed in isolation. You just don't develop develop it out of the blue.\n\nA lot of our mathematical foundation came from the Arabs and Turks, which came from the Greeks and Indians and Persians, which came from their respective proto-civilizations, etc. \n",
"We invented glass! Allowed optics for study via microscopes, battle advancements via telescopes, botany using greenhouses etc. It really did allow us to excell!",
"They weren't. Check out the book \"[1491\"](_URL_0_). It does a good job discussing it all. I believe the Mayans or someone around there even invented the concept of zero prior to the mid east. \n\nEdit: Tomorrow evening (PST) I will be glad to post some quotes of my favorite parts.",
"I think the most important factor here was the incredible amount of coastline, meaning lots of resources and trade, coupled with a relatively mild climate. Some evidence has also been found that becoming tolerant to lactose greatly increased the nutritional availability for early Europeans.",
"From what I recall from \"Guns, Germs and Steel\".\n\nIt has to do with the variety of plants/animals you have that can be domesticated, which started farming. The beginnings of domesticated plant and animals leads to high density populations capable of producing 'specialists' like priests (that justify war) and politicians (that wage war). \n\nIt also depends on WHEN you start domesticating plants and animals, because diseases and technologies take time to evolve (which help conquer others).\n\nAlso, Eurasia is mainly east-west (long) where as North America and Africa are more north-south (tall). This has huge effects on technology transfer as domesticated plants and animals have trouble travelling north-south far distances due to differences in climate. So a plant that works well in one place would die in another place if it travelled too far along the north-south axis because it would be a completely different climate (like past the African dessert). \n\nEurasia, on the other hand, the east-west axis allows technology, people, and plants/animals to be exchanged frequently (wheat could be grown in Germany, Mesopotamia, and also China), thus compounding innovation and growth of societies. \n\nI am sure there were other factors that I am missing out and it would be great if someone could fill me in.\n\n\n\n",
"Depends on definition of technology. The Americas featured by far the greatest plant breeders in the world, some very interesting medicine, decorative metallurgy and weaving and at several points cities with arguably the largest populations.",
"If you have Netflix you can stream the Guns, Germs, and Steel 3-part TV series.",
"In Charles Mann's books 1491, he makes some excellent arguments as to why the Native American cultures were technologically superior in many ways to Europe in spite of being isolated from the rest of the world. His arguments are based on two basic premises: \n\n1) That when the earliest European explorers came to the Americas they brought small pox which wiped out perhaps as much as 90% of the indigenous populations over the next century, so what we think of as the Native Americans are really the devastated remains of a culture, almost a kind of post-apocalypse. \n\n2) Many of the Native American contributions to technology aren't really recognized as such by the wider world. Basically this argument is that the Native Americans made HUGE advances in agriculture/nutrition in particular, as well as in the medicinal (brain surgery), hygiene, textile (they had a Kevlar type armor based on densely layered fabrics) and fine metallurgy technologies. Ironically their cleanliness and good health made them more susceptible to European diseases as Europeans had been living in the SAME rooms as their livestock and had been malnourished for centuries, making their diseases vibrant and abundant. Their agricultural advances don't necessarily represent technologies used today or those developed in any other parts of the world and so they get downplayed and written off. I don't recall all of them but here are some highlights I remember.\n\n-By some estimates 3/5ths off all food eaten today were developed by Native Americans such as corn, tomatoes, potatoes, avocados, squash, peanuts, chocolate and pineapples. \n\n-Corn was essentially a weed in the wild. They somehow genetically engineered/breed it into a diverse food source with over 500 variants. We only use a few of them today but they had corn species for a vast variety of purposes. \n\n-They developed a method of growing corn, squash and beans together in an extreme efficient way where each crop supplemented the other allowing for greater nutrition and field yield. I think this reduced \"rest\" time for fields somehow as well. \n\nHope that helps!",
"I will avoid the geography topic, since it seems like that has been covered, but will look at it from historical and political reasons for why they might be perceived as technologically inferior by focusing closely on the Americas.\n\n\nIn terms of the Americas, the overriding contribution for why civilizations such as the Aztec and Inca were overtaken has largely to do with politics and disease. \n\nIn terms of technology, the type of warfare conducted in Meso-America, which was a ritualized warfare with small amounts of casualties and many sacrificial prisoners. Weapons were designed not to inflict death so much as to inflict injury so that warriors could be captured (it was considered more prestigious to capture prisoners). There is also the fact that most weapons were made with stone and wood and were less deadly than many European counterparts. These facts helped contribute to European take-over but hardly explain why it was successful.\n\nDue to the political tensions between the Aztec/Mexica and the city-states they controlled and the general view that they were despotic brutes, Cortez and his men to build favorable alliances and recruit huge mercenary armies to take over Tenochtitlan. Cortez’ small army was really no match for Moctezuma’s vast imperial army without the help of other Meso-American allies. Therefore Cortez’ army of Tlaxcalan and other mercenaries aided his siege of Tenochtitlan. There were many revolts, but since the Spanish were then at the top of the political structure, they were able to command more effectively to put down any insurrections. On top of this was the fact that disease swept through populations in the Americas leaving them weakened and less able to resist foreign rule.\n\nWith the Inca, it was very similar. Political infighting between rival brothers for the throne of the Incan Empire, along with a widespread outbreak of smallpox that decimated the population of the Incas left them vulnerable to European incursion. Pizarro’s ability to sweep into that turmoil and unseat Atahualpa with 150 men, as Cortez had done to Moctezuma, and simply take over the power structures is one of the defining reasons why Spain was able to set itself up so quickly in the New World. There are several instances in which both Pizarro and Cortez could have been squashed like bugs by either emperor, but weren’t for a variety of reasons, and due to the luck and cunning political exploitations of both commanders they were able to brutally fortify their positions as leaders of both empires.\n\nIn terms of Africa, the situation was a bit different, but not completely so. Many African civilizations were quite advanced in the 15th Century, but political upheaval between rival empires and city-states with the introduction the slave trade drove many to war to claim a monopoly as suppliers of slaves. In return for exporting slaves, African states became increasingly reliant on European firearms to subdue their African rivals (a similar thing happened in China and the United States). This led to a dependency that only increased African states’ weakness in light of European advancement. \n\nIn terms of Australia, I am not very qualified to speak on that subject, but I assume it reflects more of US/British intrusion into the west of North America than the previous examples. \n",
"I think it's interesting that disease was, by far, the biggest contribution to the European victory in the Americas\n\n_URL_0_\n\nAccording to that, smallpox wiped out 95% (!!!) of the American population after Columbus landed. A fully populated America would have been so much more difficult to conquer that history would have turned out so much different. The weapon difference was significant, but was it significant enough by itself?\n\nFor some interesting alternative history, read the book Pastwatch. A bit preachy, but a cool time travel story about Columbus and the Americas.\n\nAnyway I think your question is better phrased \"why do I mostly only learn about European and Eastern-Asian achievements in school?\" ",
"A couple comments on you summary:\n\n > Domesticated animals,\n\n > Close proximity of groups of people encouraged competition and a military tech arms race\n\nDomesticated animals allow more people per square mile, which enabled said competition\n\n > Less disease allowed large groups of people to live together, allow specialisation in particular jobs\n\nLiving at higher densities and in extremely close proximity to domesticated animals actually caused a much higher disease rate (poor sanitation/drinking tainted water/crossover diseases with animals). This made Europeans immune to and carriers of diseases that wiped out large portions of aboriginal populations. \n\n\n"
]
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[
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[],
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"http://www.cracked.com/article_19864_6-ridiculous-lies-you-believe-about-founding-america.html",
"http://www.amazon.com/Guns-Germs-Steel-Fates-Societies/dp/0393061310/ref=sr_1_1?ie=UTF8&qid=1343875102&sr=8-1&keywords=guns+germs+and+steel"
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],
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[],
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[
"http://www.pbs.org/gunsgermssteel/variables/smallpox.html"
],
[]
] |
|
t3k4u
|
When I donate blood, I sometimes wonder: What happens if the blood recipient is allergic to something I recently ate?
|
Do the allergens make it into the blood stream or does the digestive system destroy any molecules that could create an allergic reaction?
|
askscience
|
http://www.reddit.com/r/askscience/comments/t3k4u/when_i_donate_blood_i_sometimes_wonder_what/
|
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"Food allergies typically act on tissues the food encounters before digestion, such as the oral and esophageal mucosa, resulting in swelling or rashes of the throat leading to constricted airways. Once the food enters the stomach the allergens are broken down before entering the bloodstream, so blood to blood transmission of allergens is minimal.",
"There are some cases of this happening, but they are incredibly rare. I think I've read about a handful of cases of nut allergens being transferred. It's possible there are other cases, but I haven't seen them or been warned about that sort of interaction. ",
"The last time I went to give blood I was turned away and asked to not come back please, since the *opposite* can apparently happen. If the donor is allergic to something, the antibodies in the blood will be transfused along with everything else, and if the recipient is then subjected to whatever the donor is allergic to, this can lead to allergic reactions.\n\nI can only assume that the effect is much reduced, since the blood is diluted, but on the other hand the recipient will have no idea what he is now temporarily allergic to.",
"Transfusions are generally packed cells... very little antibody is transfered.\n\nFun point of interest though, you can get (or lose) allergies from a bone marrow transplant. e.g. if a person is allergic to peanuts and donate marrow, the recipient can become allergic."
]
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|
1x9p9x
|
what exactly does this mean (pic in post)?
|
_URL_0_
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1x9p9x/eli5_what_exactly_does_this_mean_pic_in_post/
|
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"In some locations, failing to upkeep a property means it can be forfeited to a new owner who does want to care for the property. The sign was posted by essentially squatters who want to prove no one cares for the property. \n\nIts called adverse posession. "
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"http://i.imgur.com/1ZirFkV.jpg"
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|
2d8v8u
|
why does my cat insist on having me constantly feed him, even though he still has food in the bowl?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2d8v8u/eli5_why_does_my_cat_insist_on_having_me/
|
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"Cats are assholes?",
"My cat literally meows for me to watch him eat. I'll be in my room and will hear him meowing from downstairs so I'll go down thinking he wants me to let him outside. When I get downstairs he leads me to his food bowl and just eats in front of me. \n\nHe's a dick.",
"My cat does this. My mom, who runs her own pet care taking business (not that it makes her an expert, but she knows a hell of a lot more than me about pets), says that he most likely wants **fresh** food in his bowl, because the old food has lost some of its scent/appeal. This is of course for dry/kibble food - you give my cat (and in my own experience, any cat really) canned food or meat, and he will NOT let that go to waste.",
"It's a combination of things. There's the term \"creature of habit\". Your cat has a habit of eating while you are there. When you are not there, Something Is Wrong. Cats can also be particular about the dish, the floor covering, foot traffic in the room, and so on. Also, you and the cat have a learned behavior. You have learned to hang out with the cat when he eats and the cat has learned to eat when you are in the room."
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3c3uk0
|
swingset physics
|
... and then maybe like I'm 40 afterwards :)
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3c3uk0/eli5_swingset_physics/
|
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"In the absence of friction (or other energy sinks), a swingset, or indeed any simple pendulum, would simply continue to oscillate indefinitely between the two high points. At one extreme, when the pendulum is highest and its speed zero, the system has maximum gravitational potential energy, and zero kinetic energy. At the bottom / middle of the swing, the system has minimum gravitational potential energy and maximum kinetic energy - essentially trading height for velocity, and then it converts back as you come to rest at the other extreme. A swingset, of course, is not a frictionless simple pendulum in a vacuum. Energy is lost to mechanical friction, drag / friction with the surrounding air, and so forth, so to keep the swing swinging, the occupant must input energy into the system. This is done by moving the legs, which moves your centre of mass, increasing the available gravitational potential energy. On the back swing, you curl your legs behind you to raise the centre of mass, and on the front swing you extend them above you. At the bottom of the swing, you ideally want the centre of mass as low as possible to obtain the greatest difference between high and low, and hence greatest kinetic energy (velocity) at the bottom of the swing.\n"
]
}
|
[] |
[] |
[
[]
] |
|
3apep9
|
Which planet, if it disappeared, would affect Earth the most?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3apep9/which_planet_if_it_disappeared_would_affect_earth/
|
{
"a_id": [
"cses0ti"
],
"score": [
36
],
"text": [
"If Jupiter were to magically disappear I expect we'd quickly be exterminated by an asteroid impact. \n\nThe solar system is, to first order, the sun. Pretty much everything that goes on can be pretty thoroughly described if you just know the distance to the sun, its mass, no matter where you are in the solar system. To second order, the solar system is the sun's gravity plus Jupiter's. For example, Jupiter is about three times more massive than the other seven planets *combined.* \n\nBecause of this, Jupiter plays an important gravitational role in shepherding asteroids. Check out this [picture](_URL_0_) - white is the asteroid belt, and the colored asteroids are in Jupiter's Lagrange points or a 3:2 resonance, [which means they do 3 complete orbits of the sun for every 2 that Jupiter makes.](_URL_1_)\n\nAll of those red dots which are called the Hildas should be on unstable orbits without Jupiter and will scatter through the solar system. There's about a thousand of them.\n\nThis is made worse by the fact that Jupiter does important work clearing the inner solar system of any sort of debris that makes it in. For example, [Comet Shoemaker Levy 9 collided with Jupiter in 1994](_URL_2_), producing scars comparable to the Great Red Spot. I believe the phrase used in the popular media was \"celestial vacuum cleaner.\" If it weren't for Jupiter taking all these hits, impacts would be far more common in the rest of the solar system, which could spell disaster for our little lifeboat in space. \n\nFortunately, Jupiter isn't going anywhere any time soon. I did the mass here once, and I remember that it would require a pile of nukes 4x the mass of the moon to destroy Jupiter. "
]
}
|
[] |
[] |
[
[
"https://upload.wikimedia.org/wikipedia/commons/f/f3/InnerSolarSystem-en.png",
"http://www.exploremars.org/wp-content/uploads/2013/06/Petr-Sheirich-2005-our-solar-system-in-motion.gif",
"http://www.ifa.hawaii.edu/images/sl9/io.gif"
]
] |
||
2h4ar2
|
how do we know that we 'mixed' with other human species?
|
I was reading about it on [this Wiki page](_URL_0_) but I have difficulties understanding.
Thanks!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2h4ar2/eli5_how_do_we_know_that_we_mixed_with_other/
|
{
"a_id": [
"ckp8wbt"
],
"score": [
2
],
"text": [
"Scientists are able to analyze DNA and determine your ancestors. Certain areas/species have specific genes, and we have recently discovered Ozzy Osborn has traces of Neanderthal heritage: _URL_0_\n\nThat's how we \"know\". But evolution occurs at such a slow rate, so it's not like two subspecies of humans birthed the modern man. As evolution shows, species change over large periods of time. Millions of years."
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Archaic_human_admixture_with_modern_humans"
] |
[
[
"http://www.scientificamerican.com/article/ozzy-osbourne-genome/"
]
] |
|
2isdqh
|
If one clock orbits Earth moving very fast, why does it measure less time when, relative to the orbiting clock, Earth-bound clocks are moving equally fast?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2isdqh/if_one_clock_orbits_earth_moving_very_fast_why/
|
{
"a_id": [
"cl5dsrv"
],
"score": [
2
],
"text": [
"See the [Wikipedia article for twin paradox](_URL_0_), specifically the resolution part."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Twin_paradox"
]
] |
||
65s86q
|
During the Holocaust what was the difference between the death camps and the work camps? Also how was it decided who went where?
|
I'm interested in exactly how the camps operated differently from each other. Also were people separated based on age/health/capability or was it purely based on religion and ethnicity or perhaps geographical proximity? Additionally why did the Nazis have extermination camps at all? It seems like working people to death is strictly more beneficial for them?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/65s86q/during_the_holocaust_what_was_the_difference/
|
{
"a_id": [
"dgcw923",
"dgoswby"
],
"score": [
2,
2
],
"text": [
"_URL_0_\n\nu/commiespaceinvader answered a lot of my questions in this post, but I'm still unsure of how it was decided who went to what camp",
"Good question! I hope that you read the link given in another answer and that you found some answers there. However, I will try to give you some idea of the situation. In addition, I write about the difference between death camps and work camps [here](_URL_0_).\n\nAs you can see from the link I provided, there was a significant difference between the death camps and the concentration/work camps. In short, concentration camps served a variety of purposes from slave labor to incarceration of criminals or other \"undesirables.\" They could house German criminals, German homosexuals, Poles, clergy who protested the Nazis, communists, etc. The purpose of the concentration camp also varied depending on the commandant or the location. In some camps, the death rate was higher than at others (excluding the end of war transports of Jewish prisoners that greatly inflated death rates at those camps to which they were transferred), while at others, the goal seemed to be economic to some degree. In other words, the camps were much like every aspect of the Nazi regime, varied according to the nature of the leader in charge of it. \n\nIn the concentration camps, people might be separated based on any number of reasons, but often Jews were kept separate from others. Kapos (prisoner functionaries) were often common criminals and abused the others, with Jews and homosexuals tending to be on the low end of the hierarchy. Some camps themselves became known for specific types of prisoners (Dachau, for example, was known for the number of clergy it held). \n\nThe most famous \"selections,\" however, are associated with Auschwitz and applied to Jews. In these, men and women were separated from one another. If the work camp portion of Auschwitz was full, the entire train might be gassed without any selection whatsoever; however, in instances where \"workers\" were needed, the weak, elderly, children, and often women with children were selected for gassing. Those who were selected for work were then taken into the work camp. \n\nRegarding your last question, there was a debate between 1939 and 1941 regarding what was to be done about the Jews. As the General gouvernement of Poland became a dumping ground of Jews (creating much consternation on the part of Hans Frank, the Governor-General, who opposed it being used in such a way), the various German rulers of Polish cities with Jewish ghettos each had different goals. In *The Origins of the Final Solution*, Christopher Browning states \"a the core of the dispute over ghetto policy was a split between \"attritionists\" and \"productionists.\" As the ghettos became longer term features rather than simply collection points, Jews were paid for work and an emphasis might be on economic productivity. Alternately, such as in Lodz, while Jews worked, the focus by the German officials was on getting rid of the ghetto through \"attrition.\"\n\nWhat changed this policy seems to have been the invasion of the Soviet Union and with it the drastic increase in the number of Jews under German control. Ghettos had never been a permanent solution to the Jewish Question and had been much opposed by almost every Nazi in Poland. Moving the Jews into the East became a fascination of most such leaders. In the Soviet Union itself, Jews became the victims of the *Einsatzgruppen* as they were tasked with eliminating threats to the rear of the German army. This radicalization of Jewish policy soon encompassed those Jews in occupied areas as well. The Polish ghettos were liquidated and the Jews of Europe were relocated to the East. \n\nAll this is to say that the policy of extermination MIGHT not have been the most economically beneficial, although the linked post from the previous comment will give you more information on that. Ultimately, however, economic benefit was not the only principle at play. Enrichment of the SS leaders was key and speed was an important aspect of that. Hence theft of Jewish property trumped long term economics and slave labor. Also, anti-Semitism and a desire to exterminate the Jews played an important role. Finally, the radicalization that came along with the invasion of the Soviet Union provided impetus as well.\n\nHope this helped."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/4nz0tk/why_didnt_hitler_wait_until_after_world_war_ii_to/"
],
[
"https://www.reddit.com/r/AskHistorians/comments/47sgtq/why_is_auschwitz_the_archetypal_concentration_camp/"
]
] |
|
3ga74o
|
A friend of mine tells me every culture around the world has a myth of a great flood wiping out the whole world, and that the timelines match up indicated they are talking about the same flood. How true is this likely to be?
|
A friend of mine tells me that every culture has a myth about the great flood that wipes out the entire world. To me it seems obvious that since they only had access to their local area, and since at some point throughout history most local areas will flood, we would have no way to tell if they were really talking about the same floods or not. If there was no great flood that wiped out the whole world, which he thinks happened when the Ice Age melted 10,000 years ago, I still think it would be likely that most cultures would come up with a flood myth.
But to start with does every culture, every major culture I suppose, have a flood myth?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3ga74o/a_friend_of_mine_tells_me_every_culture_around/
|
{
"a_id": [
"ctwa4zo",
"ctwl55s"
],
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13
],
"text": [
"[Mark Isaak has collection about a gazillion flood stories.](_URL_0_) That is a lot, but not every country has one. Nor is there all that much similarity across the stories. Boats are common, but you expect boats in a flood story. Some destroy the world and we go to a new one, some just destroy the local area. Nor is there any way to somehow line up any timeline.\n\nI suspect that your friend has a confused version of the [Black Sea deluge hypothesis](_URL_1_). Roughly speaking this says that an ice dam held the Med back from the Black Sea and then it flooded. People postultulated that this event led to the various Mesopotamian flood stories (including the Noahic flood). There are several problems with that hypothesis. First, better evidence says that the Black Sea did not flood catastrophically, but rather slow enough for people to move when it was a problem. Second there is no evidence for some mass migration from the area. And finally there is nothing special about the Mesopotamian flood stories that requires a special explanation.",
"As you said, since floods, tsunamis, and sea level changes are common place events, myths and legends concerning them are also commonplace. Additionally fossils of marine life are widespread on mountains, which can easily inspire people to hypothesize that the mountains were once underwater to explain how fish bones got all the way up there. \n\nThe set of flood myths in the eastern Mediterranean and western Asia (Greek Deucalion, Israelite Noah, Sumerian Utnapishtim, etc.) have several common motifs. Perhaps they're all derived from a common ancestral legend, or perhaps they all arose as independent legends that became more similar due to cultural cross-pollination. \n\nOutside this area, flood myths and legends can be quite diverse. A common Australian motif involves children upsetting the Rainbow Serpent in its oasis, who floods the world punishment. It's basically a \"Water falls, everyone dies\" story since there's rarely any mention of survivors. They're morality tales to discourage kids from playing in unfamiliar waters. The Desert Finch Dreaming in South Australia also describes a flood, as the sea swept over the southern plains until the Desert Finch Ancestors dove into the water in the thousand to build up a high wall ([the cliffs](_URL_0_) that form the shore of the Great Australian Bight) to stop the water. This one may in fact be describing the post-Ice Age flooding of the southern continental shelf. \n\nIn a broad swath of eastern North America, a flooded world is the initial state, until Turtle offers to become the foundations of dry land prior to or during the arrival of humans. There's a few examples that alter this bit. In the Lenape version, Toad maliciously swallowed all the water. When he was injured in the fight to recover the water, it all poured out at once, flooding the world until Turtle becomes new land. In the Ojibwe version, the Gichi-manidoo floods the world to purify it, and humans have to be re-made by Nanabozho, again after Turtle becomes land. This is a rare example of the divine punishment motif in the area and may have been introduced through missionary contact.\n\nFor the Rapanui of Easter Island, the earth is *still* flooded. Their flood legend occurs sometime after the island was settled around 700 CE or perhaps a little earlier. Based on where it fits into the overall narrative of the islands history, it seems to correspond with to the time when changing weather patterns, the loss of the island's trees (needed to make voyaging canoes), and the abandonment of settlements on intervening islands cut the Rapanui off from the rest of the Polynesian world by the 1500s (interactions with the rest of Polynesia never seems to have been particularly common, but they didn't start really getting cut off until the 1200s). That the rest of the world had been drowned became the explanation for why the island was no longer visited by others, until the Tangata Hiva (Europeans, but literally \"People of Distant Lands\") finally showed up in the 1700s."
]
}
|
[] |
[] |
[
[
"http://www.talkorigins.org/faqs/flood-myths.html",
"https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis"
],
[
"https://upload.wikimedia.org/wikipedia/commons/c/c6/Great_Australian_Bight_Marine_Park.jpg"
]
] |
|
f916g4
|
How can I learn history on my own and take steps to be a buff?
|
I am a 17 year old still in high school and I am so fascinated with history. I took a world history class last year but the teacher did not really teach in depth and skipped a lot. Now I am taking US history I am loving this class and the teacher.
I want to learn the history of the world that I never truly got to learn last year (we didn’t even have a textbook) and really get familiar with it. I love history so much and I think I found what I really care about.
What things should I do to learn world history? What steps should I take? I have a vague understanding of world history but it is very broad. Where should I start?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/f916g4/how_can_i_learn_history_on_my_own_and_take_steps/
|
{
"a_id": [
"fioy8xe",
"fip8voj",
"fipaviq",
"fipvvmz"
],
"score": [
6,
5,
7,
2
],
"text": [
"That’s a pretty broad spectrum. Are there any events, eras, or regions that you find most interesting.\n\nThe sub has a series of book recommendations for all sorts of topics, broken down by subject matter. You should definitely take a look.",
"I think something that should be mentioned here is that historians are not “history buffs” in the way that most laypeople would think. History is not simply memorization of events and dates. The study of history is the study of how to contextualize events, writings, languages, and many other things so that they say something about how people lived. This can also be used to explain why people live as they did in later periods or even now. Basically, history is another sub-area in the broader study of humans and their societies. Most people don’t understand this because in high school history class, memorization of dates without context is unfortunately how it is taught. In fact, you will find that if you really study history seriously that dates matter very little and that ideas and theories about how societies worked are far more important. Any serious historical work that anyone here will recommend you will have this as a framework too. You will notice that they all have a thesis or theses about the significance of the work, even if it is a little hidden in nice writing. You will come away with really learning about something deeper, not to sound cliche.",
"History is arguably the science of the specific. At least, that's what I argue, so I suppose it must be arguable. Which is to say, while understanding the vast sweep of history is great, it's also hard to really dive into because so much of what makes history fascinating, informative and fun is the details. Often the best thing about general history is finding new rabbit holes of specific periods and topics to become passionate about and begin researching. Which is all to say, while this thread has some good recommendations on general histories, also ask yourself specifically what most interests you based on what you do know. Follow that passion! That's often what studying history is all about, whether you are a student or a hobbyist or an academic. I (and many people) find more focused interest is a lot easier to sustain and brings very tangible rewards. Which isn't to say you shouldn't study broader histories, but that if you find your passion and your curiosity pulling you toward a particular topic, follow it and see where it leads you.\n\nThis is also important for learning how to -do- history. Because studying history is in no small part about learning to think historically - how to criticize and contextualize sources, how to use those sources to infer causality, how to develop a historical argument. And that kind of thinking is often best shown in the smaller scale of more specific topic and period studies rather than in the broadest general histories - part of making a broad narrative is concealing all the work that you've done in constructing it, while it's expected that more focused histories will show their work.\n\nTL/DR study general histories, by all means, but don't be afraid to follow the rabbit holes of individual topics that interest you.",
"I am so glad that you guys exist, really!. Thank you,Thank you! As I am a fifteen years old boy I really really fascinated in thegilded age and the second industrial revolution that produce them titans of america and their fabulous suit, top hat, and walking cane.I am so really glad from the very buttom of my sub-concious mind and heart.May god keep you guys save, and I wish you guys have great success in parts that you develope impact of.Much obliged!"
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
1s9hx4
|
Why were (or even how) the battle tactics of Mesoamerican peoples so different from those of the old world at the time of contact?
|
Some reasons given to the Spanish Conquest is that the battle tactics of the Aztec differed greatly from the Europeans. Namely, that Aztecs were looking to gain captives in combat, and that cities were not prepared for the sort of European 'siege warfare'.
I understand some of the obvious differences (such as the advantage of Cavalry for the Spanish), but why are some of their tactics or type of warfare so different compared to the rest of the world?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1s9hx4/why_were_or_even_how_the_battle_tactics_of/
|
{
"a_id": [
"cdvc5a3"
],
"score": [
7
],
"text": [
"The idea that the \"Aztecs were looking to gain captives in combat\" is really quite overblown. While the taking of prisoners was important for advancement in social and military rank, the number of prisoners to gain high status was quite small -- as few as 4 captives depending on the circumstances. That the upper echelons of social/military advancement were eventually restricted only to the nobility was a further disincentive to risk life and limb to take a captive in the heat of battle. Furthermore, Postclassic military engagements were proceeded by volleys of slingstones, arrows, and atlatl darts, none of which are particularly conducive to seizing prisoners. \n\nThe focus on captive taking really conflates the actions of the elite shock troops of the noble military orders, particularly during the ritual practice of *xochiyaoyotl* (Flower War) combats, with normal combat actions. The xochiyaoyoatl were more focused on taking prisoners, but they were also arranged and limited engagements largely between the elites of two like minded groups (like the Aztecs and the Tlaxcalans) specifically for that purpose. The Aztec could, and did, engage in combats which destroyed enemy forces, stormed their cities, and resulted in massive casualties of the opposing force. \n\nRemember that the Aztecs had spent over a century fighting near continuous wars of expansion against opponents who did not always share their zeal for seizing prisoners, and yet were rarely defeated. Moreover, in combat against the Spanish, they were really fighting a small number of Europeans accompanied by much more numerous Tlaxcalans and other native forces, including former allies of the Mexica. These indigenous forces would have been using the exact same tactics as the Aztecs they were fighting against. The idea that some sort of difference between the mentality of the Spanish and the Aztecs was a decisive part of the former's eventual victory is, in this light, simply bunk. It's not even supported by the Spanish themselves, who speak quite highly of both their native allies and opponents.\n\nI wrote a bit more on Aztec Warfare [here](_URL_1_) and previously wrote about Mesoamerican sieges [here](_URL_0_). On the latter point, it should be noted that while the logistical constraints of siege warfare were felt more strongly in Mesoamerica, and thus more infrequently practiced, the Cortes' troops weren't exactly well-prepared in this either. Chronically running out of powder and having their cannons seized and destroyed, Diaz del Castillo recounts how they tried to build a trebuchet. It did not go well.\n\nThose past comments reference Hassig's *Aztec Warfare* which is the seminal work on the subject. His *Mexico and the Spanish Conquest* is an excellent companion to that work."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/AskHistorians/comments/1coe7f/siege_warfare_in_precolombus_americas_how/c9ixz4h",
"http://www.reddit.com/r/AskHistorians/comments/1lq5ma/military_capabilities_of_precolombian_mesoamerica/cc3csj7"
]
] |
|
48vw38
|
why flight attendants close the windows during the night?
|
I've been to a lot of flights and this happens all the time.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/48vw38/eli5_why_flight_attendants_close_the_windows/
|
{
"a_id": [
"d0n02k7",
"d0n14cd"
],
"score": [
5,
2
],
"text": [
"So people can sleep. Night destination-time may not correspond to night at the longitude the plane is currently over. For example, you may be arriving in Europe early in the morning, but flying partially during daytime.",
"When the sun comes up it glares like lasers through the window, waking all the passengers. That means the plane is full of wakeful, jet lagged, grumpy passengers, many of whom will insist on waking the stews from their well earned naps to make coffee."
]
}
|
[] |
[] |
[
[],
[]
] |
|
g2skw
|
Does metric expansion of the universe apply to the dimension of time? If not, why not?
|
askscience
|
http://www.reddit.com/r/askscience/comments/g2skw/does_metric_expansion_of_the_universe_apply_to/
|
{
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"c1khwcn",
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"c1kia21"
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2,
12,
27,
75
],
"text": [
"If you look at the equations:\n_URL_1_\n_URL_0_\n\nYou will see the scale factor does not apply to time. ",
"It appears that space/time could be expanding, but from what point of view would one view this happening?",
"When talking about the expansion of the universe, it's helpful to pick one of the dimensions and use that to describe how the other 3 dimensions change.\n\nFor our brains, it's easiest to pick time, and describe how the spacial coordinates change with time. Time obviously doesn't change in time, because t(t) = t.\n\nYou could pick instead, say, the x-dimension and write t, y, z as a function of x, just by rearranging the equation. And then come back and ask why the metric expansion of the universe applies to t,y,z but not x, since x(x) = x.\n\nHave a read of _URL_0_ ",
"Suppose it did. Then the most general metric (assuming the cosmological principle) we could write would be\n\nds^2 = -b(t)^2 dt^2 + a(t)^2 dx^2 (dx^2 is the metric on some maximally symmetric 3-surface).\n\nNow consider the coordinate change du = b(t)dt. Now our metric is \n\nds^2 = -du^2 + a(t)^2 dx^2 . In other words, we have shown that a metric with expansion applied to the dimension of time is equivalent to one without it, up to a coordinate change. This definition of time, u, is the most useful one, because it is the time that comoving observers agree upon.\n\nLayman language: A universe with \"expanding time\" is the same as one without it, but the latter is more useful because its definition of time is the one we are used to.",
"I'm going to try to do this without any equations. It'll make it harder, but let's see if I can pull it off.\n\nThink for a moment about what space and time are, just to get the distinction between them clear in your head: Space is that thing that separates events that are simultaneous. Time is that thing that separates events that are colocational (which is a word I made up years ago because I don't know a better one to say \"at the same place but different times\"). Of course, events can be separated by both space *and* time, but for sake of clarity, let's consider for the moment only events with *either* timelike separation *or* spacelike separation and not both.\n\nTake two events, *A* and *B.* Each event is described by a unique set of four numbers, coordinates in some arbitrarily chosen system of coordinates. We call those coordinates *t, x, y* and *z* if we're working in Cartesian coordinates, and that's just fine for this discussion, so let's call them that.\n\nSo for each event *A* and *B,* there's an ordered quadruplet of numbers that uniquely identifies that event. Using those eight numbers and something called the *metric equation* of the manifold in question, we can calculate the distance separating those two events.\n\nFor sake of argument, let's say that events *A* and *B* occur simultaneously. That is, both events have the same numerical value for their *t* coordinate. If we calculate the distance between the two events using the correct metric equation, we'll end up with a distance in space, something we can describe in terms of miles or light-years or whatever unit of length is convenient for us.\n\nBut we can also flip that assumption on its head. Instead of *A* and *B* being simultaneous, we can say they're colocated. In other words, *A* and *B* share the same numerical values for *x, y* and *z,* but have different values for *t.* We can use the same metric equation to calculate the distance between them, but this time we'll get a number that we have to describe in terms of seconds or centuries or some other unit of duration.\n\nNow, think about what *spacelike* metric expansion means. It means that the *spacelike* distance separating *simultaneous* events is a function of *time.* In other words, the distance from event *A* to event *B* when *A* and *B* are simultaneous depends on *when* we calculate it.\n\nNow, nothing's stopping us, mathematically, from flipping that relationship on its head. We could say that the *timelike* distance separating *colocated* events is a function of *space.* In other words we could say the distance from *A* to *B* when *A* and *B* are colocated depends on where, exactly, *A* and *B* are *on the manifold.*\n\nWhen we put it in those terms, we can see that this is impossible in our universe. One of the core principles that defines our universe is the *equivalence principle,* which states that the outcome of a purely local experiment is independent of where in spacetime that experience is carried out. If this timelike expansion idea were true, then experiments conducted at different places in the universe would have different outcomes; an unstable subatomic particle *here* might decay in fifteen minutes, while the exact same particle *there* might decay only after a millisecond, because the proper time separating the particle's emission from its decay would vary depending on where the particle is.\n\nSo we must reject the idea of timelike expansion *a priori.* It contradicts something we know to be true about the universe.\n\nOkay, well, what if we considered a different relationship? What if we said that timelike separation between colocated events is a function of *time* rather than location. But that's just saying that time is a function of time, which either reduces to triviality *(\"t=t\")* or is nonsensical *(\"t≠t\").* So we must reject that also, on even more basic logical grounds. (Of course, we could just postulate that the universe has two parallel timelike dimensions, *t* and *u,* and that *t* is a function of *u,* but any such theory constructed from a \"metatime\" postulate like that either reduces, again, to triviality, or is untestable, so that wouldn't actually get us anywhere. And imagining that *t* and *u* are perpendicular introduces all sorts of mathematical inconsistencies that I won't even bother getting into here, but the bottom line is everything falls to pieces if you try.)\n\nSo what we're left with is that the metric expansion we observe — in which spacelike separation is a function of time — is possible, while all other combinations of timelike separation being dependent on space, or timelike separation on time, or spacelike separation on space are either degenerate, contradictory or inherently logically invalid."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Friedmann_equations",
"http://en.wikipedia.org/wiki/Friedmann-Lema%C3%AEtre-Robertson-Walker_metric"
],
[],
[
"http://www.physicsforums.com/showthread.php?t=71053"
],
[],
[]
] |
||
4iat99
|
why do most power plants convert heat into electricity by heating water into steam and then using it to spin a turbine? is there not a more efficient way to do it?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4iat99/eli5_why_do_most_power_plants_convert_heat_into/
|
{
"a_id": [
"d2wiqm8",
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"score": [
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13,
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5
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"text": [
"None that we've found. There are ways to make the process more efficient, but nothing can reliably keep the turbines spinning at maximum capacity (their most efficient state) as consistently as steam.\n\nThough things like solar power may eventually overtake them.",
"Steam turbines are actually quite efficient and they have the advantage in that the steam can be condensed back into water at the end of the process and reused. ",
"As it turns out, a large portion of our energy production portfolio is based off of burning things. We burn coal, lignite, and natural gas to make heat. Nuclear power plants don't \"burn\" in the traditional sense, but the nuclear fuel does produce (a lot of) heat when it fissions.\n\nSo how do we convert this heat energy into electricity? Turns out the steam cycle is the most cost-effective way to do so.",
"It is possible to produce electricity using heat directly, but the technology is very inefficient. The only realy advantage this has right now is that it works with low temperatures and doesn't require any moving parts, and they are currently mostly used for nuclear batteries powering spacecraft. \n\nHeat engines using hot gas (e.g. gas engines, stirling engines) could be more efficient than steam turbines, if they were made from a material which can survive extremely high pressure and heat, since both imcrease the amount of energy you can get from heat. Unfortunately, most materials which are good enough in both regards are very expensive and/or difficult to work with.\n\nSteam turbines are currently more efficient because you can operate them at a fairly low temperature, which lets you reach very high pressure using conventional materials, and makes it possible to run them without cooling the turbines.\n",
"[This page](_URL_0_) contains an excellent summary of the efficiency levels of different power plant types. A modern coal+steam plant turns 38% to 42% of the coal's heat energy into electricity. This is considered quite efficient, and better designs have not been created that work at large scale. (Coal never *intended* to be electricity, so it's actually quite an accomplishment.)\n\nYou'll notice on the same page that hydro is way more efficient.",
" > Is there not a more efficient way to do it?\n\nNot really. \n\nWe have centuries of experience engineering steam turbines and are really, really good at it. And water is cheap and plentiful.\n\nIn terms of the pure physics of it, there is theoretical room for improvement. A typical steam turbine is about 33% efficient, where the theoretical (Carnot) limit is in the 60 percent range. However, taking advantage of this would require new engineering techniques and exotic materials that would be unlikely to make it worthwhile.\n\n"
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[
"http://www.brighthubengineering.com/power-plants/72369-compare-the-efficiency-of-different-power-plants/"
],
[]
] |
||
5xfnjw
|
what is the significance of having headphones in the correct ears when listening to music?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5xfnjw/eli5_what_is_the_significance_of_having/
|
{
"a_id": [
"dehpr9x"
],
"score": [
5
],
"text": [
"There isn't one from a music perspective, (some songs have differences in the left-right channel, but it doesn't really matter if it is reversed). The problem is with the shape of the headphones themselves. The right headphone is shaped for the right ear, so if you put it in the left ear then it will be backwards and won't be as good of a shape."
]
}
|
[] |
[] |
[
[]
] |
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