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4pobyi
|
How Integrated circuit are designed ?
|
I know that integrated circuit (like CPUs) are made from silicon wafers, but since they are like circuit board, they must have been "drawn" in some way before being printed, but CPUs contains million of transistors.
Are they automatically generated with some patterns ?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4pobyi/how_integrated_circuit_are_designed/
|
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"They are written in programming languages that specify the logical operations.\n\nThen Synthesis is performed by (a usually very expensive) piece of software to map the\nlogic to the transistors.\n\n[Some example code](_URL_1_)\n\nIn the old days chip designers were drawing huge masks with some kind of cutting\nequipment and rulers, [like for the 6502](_URL_0_).",
"yes.\n\nIt's called Very large scale integration design, or VLSI design.\n\nWith large chips, it's almost assuredly computer aided, where humans define the logic they want, or even small components, and some other program figures out what actual transistors to use how to lay them all together on the actual CPU.\n\nUsually humans will do coarse design such as \"core 1 goes here, core 2 goes here, and they connect together this way\""
]
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|
[] |
[] |
[
[
"http://research.swtch.com/6502",
"http://asic-world.com/examples/vhdl/index.html"
],
[]
] |
|
6wbc3k
|
how does the technology that sees if tennis balls are in or out work, and how come it hasn't completely replaced linesmen?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6wbc3k/eli5_how_does_the_technology_that_sees_if_tennis/
|
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"It uses camera images. The exact location and specifications of the camera, tennis balls, field lines are known. Then by analyzing the size and location of the ball on the different camera images, they can determine its actual location. \n\nWhy hasn't it replaced linesmen? First of all it's extremely expensive to set up, so in the near future it's never going to be a universal system. Secondly I'm not sure if it's possible to have it activated in real-time, to call immediately when a ball is out. Given that in football goalline technology seems to work that way, it looks possible, but I don't know the details. Finally tradition is very important in tennis, which could hold back some possible advancements. ",
"I know more about this than a lay-person should, but that's perhaps because I'm considering starting a business in this area. On this, you can AAMA - I know quite a bit.\n\nI also know this is _way_ more info than you actually care about, and nobody is going to care about this, but I enjoy talking about it, so, here goes:\n\nThe system you're talking about in tennis is called [Hawk-Eye](_URL_1_) and the first time I saw it in use was during a cricket match being shown in the UK where the broadcaster had brought it in to understand very subtle decisions almost impossible to judge by eye (cricket has a rule called \"LBW\" which in particular, is hard to get right sometimes by sight), and it quickly got engrained into the top tier of the game.\n\nThere are other systems as well. Ever wondered how \"they know\" your favourite soccer player has run 18.2km this game? That's almost certainly from the [ChryonHego](_URL_2_) Tracab system.\n\nWhen it comes to pass completion, shots on goal, etc. that data is probably coming from another system called Opta. That relies on a mixture of camera tracking and human event classification (they have people at games saying \"that frame was a pass, that frame was an attempt at goal, etc.\"\n\nIn Rugby the players are often wearing positional tracking devices that also track heart rate and letting coaches know how players are performing in real-time. I believe NFL does this too. Basketball has a mixture of systems, and in cricket, they have even more toys (I'll come back to that). \n\nYou are probably also aware that in motorsports, the objective has become \"a driver moving as large a collection of sensors as possible around a track as quickly as possible\", because the more sensors you have, the better you are at managing the data, the more likely you are to win. Hilariously, just this weekend, one F1 team has shown that their [positional analysis is easy to fool and can lead to stupid decisions](_URL_0_).\n\nThe positional tracking systems all have similar concepts: film something, then analyse each frame. In the case of Tracab and Opta, they're happy with 25 frames per second, the same as most broadcast TV systems. I would argue it's a little too low for accuracy.\n\nHawk-Eye is a much higher frame rate (500-1000 frames per second) that should aid with the accuracy. Each frame is broken down in terms of object recognition: here are the lines, here's the ball. Now look at the relationship between them and produce a data frame. The data frame will have x, y, z co-ordinates of a ball in relation to a line or some other aspect you care about, and can be fed into a piece of software that can call \"foul\" or \"goal\" or whatever you need.\n\nNow, why has it not all replaced officials? It's obviously already used to augment officials. In some tennis competitions you can actually hear Hawk-Eye make a noise on fouls that is effectively taking the place of a linesman. In EPL games, goal line technology using something like Hawk-Eye (not ChyronHego, I believe), is used to let a referee know the ball just crossed the line in case it's not obvious to them.\n\nFor some scenarios then, it is being used to replace linesmen. There are three reasons it hasn't yet succeeded in removing them completely, I think.\n\nFirstly: cost. It's not cheap. There are a lot of problems they have to take into account in getting this far. Wind, light, shadows, floodlights causing multiple shadows, they all need to be dealt with. That has led to R & D costs being quite significant.\n\nThey are proprietary systems that cost a fortune to develop, and it's a bit of a closed-shop monopoly. Setup requires a fair bit of work and there is normally a team of people running it behind the scenes at each game where this technology is deployed.\n\nThat cost is not a problem with the top tier, but the top tier of every sport normally knows its future lies in lower rungs and \"grass roots\" forms of the game. It's important that even the second division (where these systems can't be used), look and feel like the top tier. And ideally, it should be possible to play the game on a Sunday afternoon down your local park without it seeming to be futile.\n\nHuman judges aid with that. They signal \"you can do this\". The sports in which that's not possible (F1), still have alternatives, and there are some measurement systems (timing, speed, etc.) that are accessible to teens with a desire to soup up their Corolla.\n\nSecondly: not all in-game events can be tracked using these systems. Hawk-Eye can track a ball near a line being foul or not, but it can't easily tell whether a player's foot is over the line it should not be when serving, for example. \n\nEven in cricket where Hawk-Eye first made its reputation, detection of foul balls (when a bowler steps over a line) has to still be done by umpires and video review. Whether the ball hit a bat or not is done by audio detection (snick-o-meter), and heat-sensitive camera (as the ball brushes the bat, the friction warms it up enough to show as white hot on an appropriate camera). The technology isn't quite there yet to make it possible for these events to be done through camera analysis alone.\n\nThirdly: accuracy. It's pretty damned good in some scenarios but less so in others. I competed in the Manchester City hackday in July 2016 (was in the winning team, too) where we got access to Tracab and Opta raw data from some historical games. In some of those frames we were seeing the football travelling - according to their systems - at 1,500m/s - which is about Mach 5. It clearly didn't actually do that (I mean, I think Yaya Toure is _great_, but he's not _that_ good), so where did the error creep in? \n\nThat casts doubt, and to my mind, just enough to not allow it to be determining the outcomes of games on which millions of pounds and entries in history books are determined.\n\nHawk-Eye's higher frame rate is likely to make it much more accurate, so you can see it making more inroads into official calls. It makes most sense in contexts of positional review (cricket, tennis, goals in soccer), and ideally in phased-play games where there is a lot of stop-start and reviews can be done without disrupting play.\n\nTennis lends itself to all this perfectly, so the only honest answer I can give you as to why it's not everywhere is quite simply cost and the fact some in-game events can't be done through hawkeye so they need the official anyway. They'll defer to humans allow Hawk-Eye on review where it has the time to churn the data rather than in real-time.",
"A lot of sports value tradition over technology so its important to still have people on the field saying yes or no. MLB didn't even allow instant replay until 2008 which was decades after it became prominent in other sports and that delay was detrimental to the game. But lots of people opposed it because arguing with the umpire over differences in opinion is fundamental to the culture of baseball. If you scrap the humans, then there is no one to argue with and it diminishes some of the excitement of the game. Tennis is somewhat the same and the drama is a lot lower if there is a computer making the calls. ",
"To add on p7r's magnificient response, the availability is really dependant on the costs and the situation. Currently in tennis, not every big tournament has the system implemented on each and every court. The system is used as a way to contest referees and linesmen calls and not systematically call every single ball inbounds or not. The whole rallies aren't probably saved for data storage purposes, but impact points can be used on broadcast to show statistics (such as where the services landed all-match), and if the system has a 99.9% accuracy mark, there's less likely to be a lot of wrong calls upon using it 1000 times rather than 100000 times.\n\nAlso the cameras are obviously situated 360° around, to be as accurate as possible in spotting whether there is a space as small as half of a millimeter between where the ball landed and the line (which is basically the whole point, to see if the ball and line have a contact). Many cameras are essential because you wouldn't want the player's body to stand in the way of your only camera.\n\nFinally, even if the human eye isn't as accurate as the machine, a linesman wouldn't have system errors or accidentally lose a file. While it's not common, I've witnessed tennis matches where the replay wouldn't be available for numerous reasons, so the game cannot be dependant uniquely on that system for now. Also, a human response is much quicker, and the players love to keep the flow going in a high intensity game."
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[] |
[] |
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[],
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"https://www.motorsport.com/f1/news/alonso-qualifying-spa-honda-mclaren-945396/",
"https://www.hawkeyeinnovations.com",
"http://chyronhego.com"
],
[],
[]
] |
||
8okwz9
|
Are the Burmese Way to Socialism and the Khmer Rouge related?
|
Is there any relation between the Burmese Way to Socialism \(Official ideology of Myanmar, 62\-88\) and the Khmer Rouge \(official ideology of Kampuchea, 75\-79\)? They were both bizarrely distinctive strains of socialism with a largely rural basis that incorporated isolationist ethnonationalism and reactionary anti\-modernism into their worldview. Both leaders changed their country's name to reflect a glorious past they constantly referred to. Yet... I don't know of any contact or exchange between the two regimes. Did I miss something?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8okwz9/are_the_burmese_way_to_socialism_and_the_khmer/
|
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"I am not as familiar with Burmese history as I am with Cambodian but funnily enough I am currently writing a thesis which examines ethnic cleansing in each area. So, far from an expert analysis on the subject I will give you some thoughts which might constitute an answer for you.\n\nIf I understand correctly your question is about the relation between KR ideology and the 'Burmese Way', as in.. do they share common roots? Which is a fair assumption given the numerous parallels between Cambodia and Burma.\n\nTo give you a short answer it would be; yes, they are in a sense 'related', but maybe more like distant cousins \\- or maybe a better analogy would be 'convergent evolution' where two different species evolve similar traits due to their environment. The big difference, among many, I would say is their relationship to the Cold War and their foreign policy. The two states certainly 'look' similar, but some of the parallels are more superficial than relating to the same common ideological roots. The CPK were far more 'communist' than the leaders of Burma. They were aligned with China in a fairly explicit way. I would go as far as to say that Burma never had a revolution to the extent that Cambodia did either, and the revolution that the KR implemented was far outside the scope that the Burmese ever attempted. Likewise the Burmese have always been pre\\-occupied with preserving the Union of Burma in regards to dismantling the states along ethnic lines \\- this has had a huge effect on their ideology, most notably the relationship that has been fostered between Theravada Buddhism and the military junta. In cambodia the opposite was true, even when you consider the links between some buddhist concepts and KR ideology ([see an earlier answer about buddhism/Khmer Rouge ideology](_URL_0_)) and the CPK was keen to tear down Cambodian's relationship to the past. Cambodia's foreign policy was highly impacted by its relationship with Vietnam and the eventual war between them (and internal purges of the CPK in an attempt to ward off a supposed plot by the Vietnamese).\n\nI've worked on three different answers to this question and I end up deleting them. You seem to be aware of the ideological palimpsest in Burma and Cambodia under the KR, as well as the relative similarities in history between the two countries... and there are some similarities to be sure. But in effect, these similarities provide quite different outcomes and are dependent on different structures. A lot of this stems from the condition each country found itself in following WWII. Its actually what I've come up against a bit when writing my thesis, I noticed lots of the similarities you have mentioned (and more when you look at the Rohingya/Cham minorities treatment) but like I said some of these parallels are just that \\- 'they never touch'.\n\nI know this has basically been a meandering non\\-answer so I will give you one thing that directly relates to your question!\n\nYou say that you are unaware of any contact between the two, and wonder if you are missing something. Well you are! Burma was one of the few governments to that had a foreign ministry in Phnom Penh during DK. And as the CPK looked to broaden their international support in 1977 Burma's Ne Win became the first foreign head of state to visit Phnom Penh. So, I'm sorry but that is just about all I can offer you.\n\nMaybe I can offer you a better answer when I have finished my research."
]
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[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/8o3q9j/in_episode_102_of_the_waking_up_podcast_sam/e00hn81/?context=3"
]
] |
|
33l6e5
|
What is the environmental and long term climate impact of the recent Chile volcano eruption?
|
I'm curious as to the temperature variations and long term effect the Calbuco volcano eruption will have on the local environment as well as further away.
|
askscience
|
http://www.reddit.com/r/askscience/comments/33l6e5/what_is_the_environmental_and_long_term_climate/
|
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"Locally a big impact mostly from falling ash an air pollution. However globally, I doubt we'll see much impact unless this continues for several months. It is located around 41 S, so not near the tropical regions. For volcanoes to have a global cooling effect, they usually need to be erupting in the tropical region.\n\n > Above the tropics, the stratosphere's circulation features rising air, which pulls the sulfur-containing volcanic aerosols high into the stratosphere. Upper-level winds in the stratosphere tend to flow from the Equator to the poles, so sulfur aerosols from equatorial eruptions get spread out over both hemispheres. These aerosol particles take a year or two to settle back down to earth, since there is no rain in the stratosphere to help remove them. However, if a major volcanic eruption occurs in the mid-latitudes or polar regions, the circulation of the stratosphere in those regions generally features pole-ward-flowing, sinking air, and the volcanic aerosol particles are not able to penetrate high in the stratosphere or get spread out around the entire globe. \n\n_URL_0_",
"The large volcanic effects that we have seen in the past are due to particulate matter being thrown up far enough to leave the troposphere and get into the stratosphere (some 20km to 40 km in altitude), where the SO2 can form sulfate aerosols, and this can spread globally. These enhanced aerosol layers can have climate effects.\n\nI don't know anything about the Chile eruption, but it probably does not penetrate into the stratosphere, so there will be minimal global climatic effects, though still could have significant \"local\" effects.\n\nEDIT: now less humorous "
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[] |
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"http://www.wunderground.com/climate/volcanoes.asp"
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ow7yo
|
Everyone's worried about the radiation but can we harness the energy from solar flares?
|
I just watched Bob from CBC's 'Quirks and Quarks' talk about solar flares. He mentioned that the flares are massive expulsions of energy and radiation from the sun. Is it possible during Solar Max to harness energy from the electro magnetically charged sub atomic particles that are released during a Corollo Mass Ejection?
|
askscience
|
http://www.reddit.com/r/askscience/comments/ow7yo/everyones_worried_about_the_radiation_but_can_we/
|
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"It's not really feasible to construct an elaborate and expensive generator which is powered by relatively rare and extremely powerful events. When it comes to harnessing energy you want a steady and consistent supply as that is the manner it is used in and won't have to be stored. We already have solar panels to capture radiation from the sun, and building something to be powered by mass ejections would be akin to building a structure to be powered by a tornado instead of just building a windmill.\n\nThat being said if we had some reason to need a lot of energy all at once and didn't have to store it we might be able to make use of huge solar flares. For example if we had a spaceship powered by a durable enough solar sail and wanted to get some major acceleration we might be able to ride it thereby harnessing the energy."
]
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[] |
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[
[]
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fifmb
|
Advice on how to effectively study science?
|
I am in my second semester of clinical nutrition and could really use some advice on studying science, particularly biochemistry and metabolism. My background is in social sciences, which really only requires review and understanding. I have loved chemistry, microbiology, biochemistry, and metabolism- they have opened up entirely new worlds for me- but I just don't know how to study them and I'm struggling. The only thing I know to do is just review my notes over and over, but I'd like to have a true understanding of what I'm learning rather than just rote memorization. Help?
TL/DR: Social scientist's study habits are garbage when it comes to metabolism. Please advise.
|
askscience
|
http://www.reddit.com/r/askscience/comments/fifmb/advice_on_how_to_effectively_study_science/
|
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"Draw diagrams until you can make them from memory."
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[] |
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[]
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3lo3u7
|
How do denatured proteins in cooked food get absorbed and "used" in the body?
|
What I mean is: Proteins are essential components in the body for building all kind of things like building enzymes....I also know that proteins denature at high temperature and that this process is irreversible as you destroy the disulfide bond between the amino-acids. So if you cook your food for example an egg you are destroying the proteins conformation. How can it still be used in the body? Does the body regenerate the aminoacids for usage?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3lo3u7/how_do_denatured_proteins_in_cooked_food_get/
|
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"You already solved it - proteins are made from amino acids. Denaturing a protein just changes the conformation (shape) irreversibly. Your body would do that when you eat it. You need 22(?) essential amino acids in your diet that your body can't produce. Your body breaks down those amino acid chains and reconfigures them as needed.\n\nEDIT - 22 total amino acids in human nutrition. 9 essential ones that cannot be synthesized from others. Thanks to /u/n00bz0rd",
"The same process happens to ALL proteins you eat - denatured or not. They are broken down into amino acids, and those individual amino acids are absorbed into your body. Yes, even including the nonessential ones that we can make.\n\nKeep this in mind next time some idiotic alternative medicine quack starts talking about the valuable \"enzymes\" present in whatever snake oil he's selling you.",
"Functional proteins have four structures: \nVery simplified...\n1. Primary- this is the amino acid (polypeptide) chain\n2. Secondary- folding amongst the chain (alpha-helix, beta sheets)\n3. Tertiary- further folding (di-sulfide bonds, etc.) \n4. Quaternary- Subunits of a protein interacting with each other. \n\nWhen you denature (cook) a protein you are only compromising the secondary through quaternary structure of the protein. This results in an inactive protein that still has its primary structure. \n\nThis polypeptide chain is then broken down by proteases (enzymes that hydrolyze amino acid peptide bonds) and your body used the resulting amino acids however it pleases. \n\nThe extreme pH in your stomach would also denature the protein regardless of cooked or not. ",
"When proteins are broken down to the point of hydrolysis, they are amino acids. Amino acids are the building blocks of life and exactly what our body likes to work with. They take those amino acids and use them to build their very own proteins during translation.",
"Digestion of proteins is mainly accomplished by enzymes. These are protein molecules produced by your body that essentially cut up the amino acid chain into small enough pieces that it can be absorbed by the body.\n\nDenaturing the proteins first doesn't really affect this process. Also, the acid in your stomach does a really good job of denaturing them anyway.\n\nHere's a good description if you are interested in the details:\n\n[_URL_0_](_URL_0_)",
"Proteins are like Legos. Amino acids are like Lego blocks. Cooking protein is akin to when my son leaves his Legos on the floor and I stick them together in random ways and then hide them from him. The blocks are still there, just not in the intended order. \n\nPepsin and other enzymes (ironically made of proteins) pull the amino acids apart one by one and the body is then able to either fourth take apart the amino acids or reuse them to make proteins, hormones and enzymes.",
"You do not reuse proteins. When you eat them you digest them. You denature them in the acid in your stomach, you chop them up roughly with pepsin, trypsin, and other peptidases, and then you cut them into their individual amino acids for reuse. You also break down a lot of these amino acids and process them further, and then you make your own as well (you make a lot of them). You are not made up of the protein you eat-which is very good, because unless you ate every part of a human you would be in serious trouble, you are made up of the amino acids you obtained from the protein you eat, and denaturing-breaking disulfide bridges unfolding a protein, has no impact on the nutritional content of your food.",
"proteins can't be absorbed into the body without being denatured anyway.\n\nyour body doesn't actually use egg proteins. it breaks down the egg proteins into the amino acids, then builds its own proteins from the amino acids.\n\ncooking breaks down the proteins partly anyway so it's easier to digest."
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2kfgkc
|
What did the Founding Fathers do for fun?
|
Did they like sports? What did they do on holidays? Hang out with family, or each other? What kinds of drinks and foods did they like?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2kfgkc/what_did_the_founding_fathers_do_for_fun/
|
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"[terrible one-line answers about marijuana and sex] \n\nPlease stop posting these. People come to AskHistorians for in-depth, comprehensive and *factually accurate* answers. Please take the time to review our rules - our [section on in-depth answers](_URL_0_) in particular - before commenting.",
"Washington's passion was Mount Vernon. When he wasn't leading an army or in some elected position, he was designing modifications to the house or inspecting the land regularly. He also enjoyed land speculation (though it was as much a hassle for him as a source of pleasure). Even when he was in office or on campaign, he would dedicate some time each week to write letters to his Mt Vernon managers, such as his cousin Lund Washington, advising them on crops to plant or projects to undertake in the manor. Both Chernow and Ellis, biographers, argue that writing these letters were times when he would take a break from the stresses of whatever position he was holding at the time and unwind over the latest reports from home. \n\nEDIT - Oh, foxhunting, at least in his youth. To quote Ellis: \"Washington spent between two and five hours a day for forty-nine days in 1768 on horseback pursuing the elusive fox\". He was such a devotee to the sport that he bred his own foxhounds. He also engaged in a lot of other things expected of Virginia planter society, like card-playing (to which he kept accounts of his wins and losses) and balls. ",
"Well, George Washington was known to make applejack -- an apple based liquor. According to Laird's (_URL_0_), he asked for their recipe and created his own. Most sources seem to indicate that he was really fond of the stuff (_URL_3_ and _URL_2_ both make unsourced claims), but I'm going to guess that was one a few things he would have liked.\n\nEdit: Since I am on the subject of alcohol: Thomas Jefferson was fond of wine. He travelled to France, buying bottles up and even tried to have vineyards of his own. See _URL_1_ and _URL_4_ for sources. However, it is very important to note that no actual, verified bottles of wine bought by Thomas Jefferson have ever been found. The bottles bought at ridiculous prices by American billionaires were forgeries. See *The Billionaire's Vinegar* for that story. If you are wine person, enjoy historical mysteries, or anything like that, you might enjoy the book.\n\nI promise I am not an alcoholic. I just know a lot about booze for some reason. And I might have a bottle of Laird's around that I was just enjoying.\n\nEdit 2: I'll try to remember what the other founding fathers drank. I might have to do some research. (And at this point, Samuel Adams working as a brewer feels like cheating.)",
"John Adams loved returning home to his Braintree/Quincy based farm, where he could be with his wife, Abigail, his children and eventually grandchildren. Between his postings in the government, and after his re-election defeat, he was an ardent farmer, working the land.\n\nHis main sport was walking, which he did almost every day, whether at home, in Philadelphia or in a posting abroad. Like many of the other founding fathers, such as Jefferson, he believed such physical exercise was important to overall health.\n\nMost holidays were religious, and Adams was a devout man who spent those holidays surrounded by family. When back in Massachusetts after 1800, he would also attend the 4th of July celebrations in Boston where he and other Massachusetts founding fathers were honored.\n\nReading was his major pastime, especially the classics. McCullough makes frequent reference Adams' love of Cicero, and Adams was known to read and reread these in Latin, as well as English law books, Shakespeare and works in Greek and French. \n\nHe also loved to write, as evidenced by his treasure trove of letters, mainly between him and Abigail, but also with other founding fathers and notable contemporaries. \n\nFrom David McCullough's John Adams, who extensively used Adams' own correspondence as source material, mostly available at the Massachusetts Historical Society.\n\n",
"Benjamin Franklin apparently had opinions on food which were just as strong as his opinions on everything else. There's a website [here](_URL_3_) with excerpts form his (copious) letters describing food - his love for which is to be expected, given his, um, waistcoat size. He appears to have been an extremely adventuresome eater, introducing American foods like Cranberry to Europe and Tofu to the US, but also very fond of the familiar, as he had his wife send him barrels of apples. He also had some concerns about the health of foods and was apparently a vegetarian for some time, and cautioned moderation in eating. \n\n\nAs for hobbies... well. He did so many things and monetized them I'm not sure you could call them hobbies. [He invented](_URL_1_) the glass armonica, bifocal glasses, an improved stove, the odometer, a sort of swim fin, the lightning rod... etc... \n\nProfessionally he was a printer, which most people know from Poor Richard's Almanack, but he printed [a lot of other stuff too](_URL_0_). He was a noted writer. Writing takes a lot of time and he also had a [lot of correspondance](_URL_2_). \n\nI'm not sure how much time he had left over after all that, what with the travel, the being married, the studying, the politics, and everything else he did. I don't think he sat still much. \n\n\n",
"So far it's Farming and 'rich guy stuff' (running businesses, land buying and maintaining), what did regular people do?",
"Benjamin Franklin enjoyed the company of women/ was a womanizer, depending upon how you want to frame it.\n\n_URL_0_\n\n > Benjamin Franklin had Anna-Louise d`Hardancourt Brillon de Jouy. And Madame Helvetius. And Margaret Stevenson. And Polly Hewson. And Madame Foucault. And Countess Diane de Polignac. And Countess Wilhelmina Golowkin. And Catherine Ray. And Georgiana Shipley. And Madame Le Veillard. And Madame Le Roy. And Countess Houdetot. . . .\n\n > And, of course, Deborah Read, his wife of 38 years.\n\nhe penned a guide on what kind of woman to seek in sexual relations, counseling the company of older women, because\n\n_URL_1_\n\n > 1. Because as they have more Knowledge of the World and their Minds are better stor'd with Observations, their Conversation is more improving and more lastingly agreable.\n\n > 2. Because when Women cease to be handsome, they study to be good. To maintain their Influence over Men, they supply the Diminution of Beauty by an Augmentation of Utility. They learn to do a 1000 Services small and great, and are the most tender and useful of all Friends when you are sick. Thus they continue amiable. And hence there is hardly such a thing to be found as an old Woman who is not a good Woman.\n\n > 3. Because there is no hazard of Children, which irregularly produc'd may be attended with much Inconvenience.\n\n > 4. Because thro' more Experience, they are more prudent and discreet in conducting an Intrigue to prevent Suspicion. The Commerce with them is therefore safer with regard to your Reputation. And with regard to theirs, if the Affair should happen to be known, considerate People might be rather inclin'd to excuse an old Woman who would kindly take care of a young Man, form his Manners by her good Counsels, and prevent his ruining his Health and Fortune among mercenary Prostitutes.\n\n > 5. Because in every Animal that walks upright, the Deficiency of the Fluids that fill the Muscles appears first in the highest Part: The Face first grows lank and wrinkled; then the Neck; then the Breast and Arms; the lower Parts continuing to the last as plump as ever: So that covering all above with a Basket, and regarding2 only what is below the Girdle, it is impossible of two Women to know an old from a young one. And as in the dark all Cats are grey, the Pleasure of corporal Enjoyment with an old Woman is at least equal, and frequently superior, every Knack being by Practice capable of Improvement.\n\n > 6. Because the Sin is less. The debauching a Virgin may be her Ruin, and make her for Life unhappy.\n\n > 7. Because the Compunction is less. The having made a young Girl miserable may give you frequent bitter Reflections; none of which can attend the making an old Woman happy.\n\n > 8. 8thly and Lastly They are so grateful!!\n\n\n\n\n\n"
]
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|
[] |
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[
[
"http://www.reddit.com/r/AskHistorians/wiki/rules#wiki_write_an_in-depth_answer"
],
[],
[
"http://www.lairdandcompany.com/ancestry.htm",
"http://www.monticello.org/site/house-and-gardens/vineyards",
"http://www.slate.com/articles/life/drink/2011/12/george_washington_loved_the_stuff_and_you_might_too_.html",
"http://www.seattleweekly.com/2008-01-09/food/before-there-was-bourbon-there-was-applejack/",
"http://www.monticello.org/site/research-and-collections/wine"
],
[],
[
"http://www.loc.gov/exhibits/treasures/franklin-printer.html",
"http://www.ushistory.org/franklin/info/inventions.htm",
"http://franklinpapers.org/franklin//",
"http://www.benfranklin300.org/etc_article_foods.htm"
],
[],
[
"http://articles.chicagotribune.com/1990-05-06/features/9002070774_1_poor-richard-lucy-mercer-franklin-delano-roosevelt",
"http://www.swarthmore.edu/SocSci/bdorsey1/41docs/51-fra.html"
]
] |
|
batcsj
|
which consequences of a dam being built lead to environmental change/damage?
|
I understand that when a dam is built it frequently has massive effects on the surrounding nature (though I'm unsure to what degree this damage is caused up and down stream respectively).
But why? Disregarding the damage that BUILDING the dam would cause for a moment, wouldn't this be a zero sum situation? Water has to build up in the reservoir first, sure. But the input doesn't change. Eventually the dam has to be opened to allow through an amount of water equal to what the river brings in or it would flood over the top.
By neccessity then, the same amount of water would flow further down the river, yes?
So where does the harm to nature come from? Is it solely because of the building of the dam?
Thanks in advance, everyone.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/batcsj/eli5_which_consequences_of_a_dam_being_built_lead/
|
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"One problem is that the dam floods the valley behind it, turning it into a lake. This kills virtually everything that was previously growing in the valley.",
"Opening a spillway creates a a current of water the down stream river life is not used to. From 1500 cfm to 35,000 cfm will wash the life of the river down to rock. This is only one issue.",
"One problem is that fish can’t swim *up* a dam to spawn. The Southern Resident orcas are starving to death because they can’t find enough salmon and a major cause of that is dams that prevent salmon reproduction. ",
"For a hydro dam, the water is eventually released downstream. However, this may be very far downstream. Look for photos of penstocks (_URL_0_). The turbines / generators need to be at a much lower elevation that the dam, to extract as much energy from the flowing water as possible. \n\nLook at the map on the first page of this PDF: _URL_1_\n\nFrom the dam, the water misses most of the river as it goes through the power tunnel, and then is released right at the ocean.\n\nFor irrigation / drinking water dams, the water is piped to other locations. This reduces water level / flow in the river, increasing temperature, possible killing fish. Also can reduce level of the water table below the dam, killing plants are trees.\n\n"
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"https://rittmeyer.com/fileadmin/user_upload/bilder/messtechnik-anwendungen/wasserkraft-druckleitungsueberwachung.jpg",
"https://www.bchydro.com/content/dam/BCHydro/customer-portal/documents/corporate/safety/dam-safety-report-q3-february-2015.pdf"
]
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|
devfls
|
Where are we in the current Milankovitch cycle? And when would the next ice age be (if there was no human cause climate change)?
|
askscience
|
https://www.reddit.com/r/askscience/comments/devfls/where_are_we_in_the_current_milankovitch_cycle/
|
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"Firstly, there isn't a single Milankovitch cycle. Milankovitch cycles describe a set of different cyclical changes in the Earth's orbit around the sun and rotational axis. Whilst this is a simplification, there are three main cycles that respectively control changes in eccentricity of the Earth's orbit, the tilt/obliquity of the Earth's rotational axis, and the precession of the Earth's orbit. These cycles in turn control the distribution and seasonal cycle of solar radiation across the Earth. \n\nRelating these changes to climate is not trivial. For approximately the past million years, glacial-interglacial cycles (calling them ice-ages is technically incorrect as geologically, an ice-age is simply when permanent ice-sheets exist on Earth) have followed the ~100,000 year eccentricity cycle. However, this certainly was not the case for much of the geological record - at different times in Earth's past, the key frequencies the Earth's climate has been sensitive to appears to have changed.\n\nThere is very good evidence that Milankovitch frequencies do indeed modulate glacial-interglacial cycles throughout geological history, but it's important to understand that it is nowhere near as simple as simple as simply going \"We are at phase X in frequency Y, therefore we are in a glacial/interglacial\". The actual changes in solar radiation involved in Milankovitch cycles are small and whilst they do indeed appear to _pace_ glacial-interglacial cycles, it is other geological and climatological processes that amplify these cycles to actually create the large changes in the Earth's climate. \n\n**To strictly answer the question \"Where are we in the current Milankovitch cycle\"**, take a look at [this graph](_URL_1_). The first green line is the eccentricity cycle which is the dominant pace-maker of glacial-interglacial cycles at the present and as you can see, we've just passed a local maximum. If you compare the first green (eccentricity) line with the brown and green lines at the bottom (which for the sake of this explanation you can read as being related to global temperature), you'll see that the peaks in the eccentricity curve do indeed correspond fairly well with the peaks in the climate curves. However, aside from this, they are very different and this is precisely because of what I mentioned before: Milankovitch cycles are only one part of the story, and it is other processes that transform these cycles into the actual climatic effects we observe. \n\n**So when would the next glacial have been?** If you scroll to Table 2 in [this paper](_URL_0_), you can see a range of estimates for the duration of interglacials throughout the past 800,000 years, including the present interglacial (MIS1). You can see that the typical interglacial duration is around 10-20,000 years, and we're currently about 12,000 years into the current interglacial. We therefore might have expected the current interglacial to end within the next ~10,000 years, possibly significantly less. Of course, anthropogenic carbon emissions may have changed this significantly. For example, [this](_URL_2_) paper suggests that we may have delayed the next glacial by ~100,000 years."
]
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|
[] |
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[
[
"https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2015RG000482",
"https://upload.wikimedia.org/wikipedia/commons/5/53/MilankovitchCyclesOrbitandCores.png",
"https://www.nature.com/articles/nature16494"
]
] |
||
1jeps5
|
why people need to be raised and schooled to live well as a person, but my cat, who's not around other cats, knows how to live well like a cat?
|
Hard to explain. Pets have their instincts that help them survive, why do humans need help in order to live a good life?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1jeps5/eli5_why_people_need_to_be_raised_and_schooled_to/
|
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"I've written and deleted about 5 starts to this answer.\n\n* animals in the wild teach each other how to hunt and survive - watch anything by David Attenbourough. \n\n* pets don't need many of their instincts to survive - we give them food, we give them shelter. Also, this is why animals from captivity don't do well in the wild. \n\n* in terms of instincts, humans have them - like fight or flight. These things are hard wired in.\n\n* in order to get ahead in the human world, you need money. Money is gained (mainly) by selling your time. We go to school so we can charge more for our time than other people. Animals don't have money, so they need to hunt, build their own shelter etc. whereas we can trade money for these things. ",
"One of the trade offs we made in our evolution for more powerful brains that take up a quarter of our blood supply was that it takes us longer to come online. Our brain starts as a plastic bin of parts that grow together and adapt to our culture as well as the tasks we demand of it to live in a society. As our society progresses, this changes and we need to change how the brain is programmed to keep up with those changes to be successful. ",
"You pretty much answered it yourself. Cats have instincts. These instincts are to eat, hunt, play, ect... \n\nYou have the same instincts more or less. A baby knows when it is hungry, even if it can't express this in words it knows to cry.\n\nAs an adult, humans live in a society which we created so we have to be taught how to fit in. Society changes very quickly (on a evolutionary time scale) so humans don't have time to evolve instincts on how to be an engineer or doctor.\n\nOn the other hand, we have evolved social skills and social instincts that help us fit into a social lifestyle, just like many other primates. Just one example of naturally living well as a person is our sense of empathy.",
"Our pets *do not* have instincts to help them survive. A domesticated animal will have a hard time surviving in the wild. Likewise, a feral animal makes a shitty pet. \n\nDomesticated animals have been bred to be dependent on the owner. My cat does not eat unless I buy her food. She does not shit unless I clean the litter box. Not exactly instinctual. \n\nThe rest is beyond explanation because it is silly to compare a human being to a housecat in terms of intellect and cognitive ability. \n\nEDIT: Humans are capable of relying solely on instinct to survive. But survival mode and living \"a good life\" are polar opposites.",
"This isn't very true. My dog hasn't had another dog to play with in years. She is socially awkward. She freezes when she sees most dogs. It's like she forgot their language. She'll smell their ass but won't let them do the same.",
"We don't live like humans anymore.",
"Cats have 95% firmware, 5% software. \n\nHumans have 75% firmware, 25% software.\n\nThe extra software that humans have is language and culture. These take a lot of time to program.\n\n",
"Animals can learn, but it is not by learning that they become dogs, cats, or horses. Only man has to learn to become what he is supposed to be.\n -Eric Hoffer\n\nJust a nugget from one of my favorite philosophers.",
"In short it's because most humans don't behave like humans.\n\nTribes in Africa (or wherever) that would cut your head off, rape your wife and daughter, and then eat the lot of you without a second thought? That's humanity. \n\nEverything else is cultural training.",
"It's our survival mechanism! I'll explain. \nWe can't hunt with teeth and nails alone, we hardly have any. We're not quick enough to chase a rabbit. Our skin is too thin to protect against those who have teeth and nails. But we've made it this far in evolution, so we must have found some way to adapt, right? Yup. \n\nHere's what we do instead of all that: we're born while our brains are half developed (so the physical stuff is formed at least) but the rest of the brain development happens AFTER we're born. That means we don't have a cat's instincts. How does this benefit us? It means that WHEREVER on the planet we happen to be born, *we can adapt to that region and thrive in it.* Our habits aren't set in stone so that we can make habits that let us kick ass in a variety of situations.\n\nThis development solidified roughly around the Ice Age when we started having to walk to find food, which meant walking upright, which means tighter birth canal and a smaller head that can come through this birth canal - smaller brains at birth. \n\nSo your kitty can survive well - only by doing exactly what a cat does, whereas we can survive on a mountain, in the sea, on Wall Street, or in a ghetto.\n\nFeel free to correct me, this is just my version of what I've read as someone who wants to pursue medicine. Hope this helps, OP!"
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78zhjo
|
How much authority did Kaiser Wilhelm II actually have during the First World War?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/78zhjo/how_much_authority_did_kaiser_wilhelm_ii_actually/
|
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"Hi, I'm a student of German and politics rather than history directly. I can't provide a hyper detailed account of Wilhelm II's role in the First World War but what I can do is give some background to the constitution of the German empire - especially how it relates to the Kaiser - and some of the background leading up to in the Bismarck period (as constitutions and Bismarck are some of my areas of interest).\n\n*the constitution:* the constitution of the German Empire was a lot like the constitution of the later Weimar Republic (for those of you aware of it) except with far fewer rights. \n\nThere are three important actors in the constitution for our purposes here. The Kaiser, the Chancellor/Prussian first minister, and the Reichstag (parliament). Unlike in other Western European states of this time, the hereditary Kaiser was arguably the most important individual in government. This is because he had the power to appoint (and remove) the chancellor, who was effectively head of government. The parliament's consent was needed in order to pass legislation and budgets, but the parliament could not dismiss the chancellor and so didn't necessarily have the ability to intervene in day to day governance. \n\nDuring the early period of the German Empire whilst Wilhelm I was Kaiser the Kaiser typically left most affairs of state to the first minister. The Kaiser would simply set out broad objectives. In accordance with this Wilhelm I appointed Bismarck chancellor who is one of Germany's most effective leaders ever. Bismarck stayed on this job for decades and drove his own policy agenda. \n\nAfter Wilhelm I died - and 100 days later the crown prince also died - Wilhelm II took the throne. Wilhelm II was a very involved Kaiser. He had personal disagreements with Bismarck and so dismissed him as chancellor after decades of service shortly after acceding the throne. Wilhelm II made a string of foreign policy announcements which have been considered by diplomatic historians as wild and inconsistent - even getting the name 'zigzag diplomacy'. This included trying to court Britain to join their bloc in the upcoming war whilst also announcing road building projects and colonial ambitions that threatened British colonial interests. \n\nAs for the war itself I am no expert so can't speak on that. But given that the German constitution afforded Wilhelm II huge political and legal powers and influences, and given the character of Wilhelm II as an involved monarch it likely he continued playing an important role. And as for the lead up to the war Wilhelm II is more responsible than any other individual, maybe even more so than the assassins in Sarejavo. \n\nSources \n\nPreusens Könige: ein Leben zwischen Hoffnung und Revolution ( Heinz Ohff)\n\nBismarck, (Korb)\n\nVarious trips to the Deutsches Historisches Musuem\n\n",
"During the war, Wilhelm's authority varied.\n\nAt the start he was the supreme commander of the German armies and was very involved (not in decision making, but in looking at the results) of \"his\" armies. He watched their progress jubillantly, was angered when they lost, and pleased when they won.\n\nAs the war dragged on, cracks began to form, starting with the military high command. To explain this, let's start with the war itself.\n\nWorld War I for Germany was divided in two: the Western Front, comprising France, German Elsaß-Lothringen (Alsace-Lorraine), Luxembourg, and Belgium; and the Eastern Front, a huge space split into Germany's sector, Ostpreußen (East Prussia), Silesia, and Russian Poland, and Austria-Hungary's southern sector, primarily focused around Galicia (Austrian Poland/Ukraine) and the Carpathian Mountains.\n\nThe Schlieffen Plan was developed by Germany to counter this was, and was Germany's only war plan: it was created by Chief of of the Imperial General Staff Field Marshal Alfred von Schlieffen, and taken up and refined by his replacement Moltke the Younger. It was Germany's only plan as both field marshals saw it as the only way Germany could succeed, and a new plan in this era took literally years and hundreds of staff to complete: it was essentially a stack of papers detailing train times and cargoes, orders for generals and their officers, and the use of roads by X for Y time.\n\nThe Schlieffen Plan necessitated Germany destroying France in 4-6 weeks so Germany could focus all of its might on Russia, presumed to be the stronger (and definitely more numerous) power. The hope was that France would be crushed and Paris taken in a short span of time, the French routed as quickly and efficiently as they were in the Franco-Prussian War that created the German Empire.\n\nKaiser Wilhelm was absolute sovereign of his empire and an involved man in the running of his country, but he could not stop his country's entry into the Great War for two reasons: 1) because Russia mobilized first, and 2) because if Germany mobilized, it *had* to use the Schlieffen plan; there were no alternatives. In this sense, he had little power, but at the beginning of the war it was still he - at the insistence of his generals - that ordered German mobilization.\n\nGoing back to the point of it being a two front war, German High Command, and Kaiser Wilhelm, were based on the Western Front once the Schlieffen Plan ground to a halt. But in Liege, the great Flemish fortress-city, a man made himself renowned by practically single-handedly capturing what was regarded as one of the greatest fortress complexes in all of Europe: Erich von Ludendorcf.\n\nLudendorff was regarded as a hero and personally awarded a medal by the kaiser, and shipped off to East Prussia when it was learned two Russian armies invaded far sooner than expected. Paul von Hindenburg was made commander and Ludendorff his chief of staff, and they were to protect East Prussia, traditional homeland of the Junkers elite (Prussia's military class) from the Russian incursion.\n\nOn the western front, Moltke was replaced with Field Marshal Erich von Falkenhayn; this was a momentous event, and Ludendorff would later say \"I can only love or hate, and I hate Falkenhayn.\"\n\nAs the Western meatgrinder intensified, the outnumbered Germans in East Prussia discovered that the Russian armies had split up and were too far away to support each other. Ludendorff and Hindenburg completely encircled and destroyed the first in the Battle of Tannenburg, for which they attained enormous prestige and respect of their prowess, and then nearly did the exact same thing to the second at the Battle of the Masurian Lakes.\n\nThis was the beginning of the end for Wilhelm. Despite their victories, Ludendorff - a worriable man - knew that the Russians had superior numbers and feared they could overrun Germany. In the West, the Battle of the Marne that had caused Moltke's downfall had sapped German strength, and so Falkenhayn felt he could not send troops east. When Ludendorff demanded them, Falkenhayn sent less than he liked - and so the animosity began.\n\nLudendorff saw their victories over the undersupplied Russian armies and repeatedly requested more troops and the ability to go on the offensive, trapping or destroying Russia's Polish armies and ending the enemy's offensive power; German High Command rebuffed him repeatedly.\n\nDuring this time, Hindenburg pretty much stopped being a general, and let Ludendorff do most of the military work: he slept, ate, and lazed around, visiting planning rooms rarely.\n\nLudendorff, the Hero of Liege and Tannenberg, presided over further victories over the Russians. Wilhelm grew increasingly dissatisfied with Falkenhayn, who met his end after the disastrous and pointless bloodbath that was Verdun and the British assaults at the Somme. Wilhelm made Ludendorff \"Quartermaster General\" and Hindenburg *de jure* chief, but in reality Ludendorff was the leader.\n\nThis is when Wilhelm's power began to slip. The kaiser was never a terribly strong-willed man, and Ludendorff was pretty much unstoppable due to his achievements. He gained more and more powers, as Quartermaster General grabbing more ways to run the war effort by slowly running the government as well as the military to an almost obsessive degree.\n\nThe climax in Ludendorff's rise to power (imo) came when he and the military lobbied for unrestricted submarine warfare; the kaiser was reluctant/opposed and was supported by his chancellor. Ludendorff demanded, and got, the submarine warfare allowed, and then threatened to resign unless his chancellor was sacked; Wilhelm relented, and so was no longer Germany's head of state. \n\nFrom this point on (earlyish 1917) Ludendorff was Germany's military dictator in all but name, controlling all levels of the German state. He even slowly took over Austria's military decisions as the Hapsburg regime crumbled and grew to be nothing more than a weak puppet of Germany's. His resignation days before the war formally ended can be said as marking the end of the German Empire.\n\nOn Hindenburg, he held very little, and was less than interested in, running Germany; even as Chancellor of Germany during Hitler's rise he had a distaste for the man and was nominally a monarchist, being from the old Junkers elite. Nonetheless, he still didn't stop Hitler, and his only truly notable action during the war was his leadership during Tannenburg.\n\nSource: G. J. Meyer's *A World Undone*"
]
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||
4l529q
|
Does the surface of the Earth "flatten out" to any extent due to space-time curvature?
|
I apologize, I know it sounds like a stupid question. I'm thinking of that pithy line, "mass tells space how to curve, space tells mass how to move." I remember visual gravitational models that suggest that heavy astronomical objects acts a little like dimples on a canvas, drawing objects to them and "curving" straight line motion. My question is, how does this apply to us here on Earth, much closer to the center of our planetary mass? Do we perceive the Earth as more "flat" because of this?
EDIT: awesome! Thank you all for your comments. I'm absolutely fascinated reading through them. You invested some real time explaining this to me and I really appreciate your effort!
|
askscience
|
https://www.reddit.com/r/askscience/comments/4l529q/does_the_surface_of_the_earth_flatten_out_to_any/
|
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"The answer is yes or no depending on exactly how you phrase the question. Let me explain:\n\nLet me just specify first that these effects are *minuscule*. Basically Earth's mass curves spacetime, sure; the components of curvature relating time and space are pretty large and are what gives you the gravitational force, etc etc. But there's also space-space curvature, meaning that at every given instant in time, space is curved itself too. But this is a very, very small effect. It's only perceptible in the context of precision experiments. But let's talk about it anyway.\n\nLet's assume Earth is perfectly spherical and smooth, and is not rotating.\n\nSo you want to know about the curvature of the surface of the Earth, which is a sphere, a 2d surface. Curvature in general is indubitably complex to quantify and explain, but for surfaces becomes very simple: it's describable completely by a single number, the gaussian curvature K. When K > 0 at a point, your surface looks sphere-y, when K=0 it looks flat, and when K < 0 it looks hyperbolic-y.\n\nThe Earth is as we said spherically symmetric and so whatever the value of K, it has to be constant over the Earth.\n\nThe fundamental piece of math I am going to use is called the Gauss-Bonnet theorem. For our specific case, it tells you that if you have a surface of constant curvature K, of area A, then this formula holds:\n\nA * K = 2π * χ\n\nχ is an integer called the Euler characteristic of the surface. You can look up what it is (it's easy!) or you can also not and I'll just tell you the sphere has χ = 2.\n\nSo we know that our curvature has to be\n\nK = 4π/A\n\nNo escaping this. Even though space can be severely curved, this relationship has to hold. It's a theorem and bears a very important person's name, so yeah. Note that A is the area as measured by someone living on the surface. If you use a tape to measure the length of the equator, you can also compute A (divide by 2π, square, multiply by 4π).\n\nNow, if space was flat, we would use A = 4π R^2 and so conclude K = 1/R^(2), which is the usual formula for the curvature of a sphere. However, A = 4πR^2 is **false** in curved space. R would be the proper radius, that is the actual distance from the centre of the Earth to the surface, measured by actual rulers. Freaky but true. A is actually a bit less than 4πR^2 iirc.\n\nSo here we have this situation. Let's say you define an \"effective\" radius r through A = 4π r^(2). As we said R=/=r. The curvature is then K = 1/r^(2). Your question could be phrased as \"if we add the effects of general relativity, does the Earth gets a variation in curvature as compared to what we would expect?\". \n\nWell, *what* do you expect? You cannot fit the normal flat-space Earth, with A=4π R, in the curved space created by its own gravity - you need to change something. Either you keep the radius fixed and make the surface area smaller than 4πR^2 to accomodate, or you keep the surface geometry fixed and increase the radius.\n\nIn case one the area gets smaller so K gets bigger, so the Earth would be *less* flat than usual, not more. In case number two, K is unchanged. As you can see, it's really just a question of defining what you want to keep unchanged."
]
}
|
[] |
[] |
[
[]
] |
|
3gewrf
|
Do nerve cells/nerve systems work like actual circuits?
|
I.e. Do nerve cells have the equivalent components of inductors, capacitors, resistors, power sources, etc., and can the brain/nervous system be modeled like this? Also does memory in nerves work at all like simple digital memory/logic gates?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3gewrf/do_nerve_cellsnerve_systems_work_like_actual/
|
{
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"ctyge41"
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"I don't know too much about electronics yet so bear with me and let me know if I make a mistake. Neurons work very differently than our electronics. They're vastly more complicated and more simple at the same time. For one, each individual neuron works kind of like a simple transistor. It has two states: either on or off (firing or not firing). \n\nOn the individual level, neurons switch on and off by opening specific channels that let in potassium or sodium. The fired vs. not fired state depends on if there is a higher concentration of sodium or potassium in the head of the neuron. This is different than transistors (I believe) that allow for either the flow of current or the interruption of current. Neurons are also an all or nothing kind of thing. I hear there are transistors now that take into account how much current that is being applied to it as a way of storing data. The brain's neurons either fire fully or not at all. You can think of them as a transistor with a wire sticking out of it that connects to another nerve cell. \n\nNeurons also have the capability to tell other neurons to fire (this is called a synapse), something I do not believe is present in electronics. The channels that block synapses from happening are voltage gated and only open when a specific set of situations happens. The closest I could come up with (with my limited knowledge of electronics) would be an integrated circuit. The brain also has the ability to form new neural pathways. For example, when you're learning a new language there's a specific pattern that your neurons are firing in. The brain remembers that specific way to fire the next time a situation comes up. \n\nAs for the specifics like resistors, capacitors, inductors, etc... the nervous system doesn't really have anything comparable. The way that we use electricity is we can control and modify voltage, resistance, and current to suit our different uses. The nervous system doesn't really do that. What it does is that it just has tons of different pathways that it can choose to fire neurons. I can't think of anything that would be similar to capacitor where it stores charge for later use and fires it when needed. I suppose if you want to go extremely technical, neurons are like that in a sense because they're constantly ready to fire being that the gradient for potassium and sodium are kept out of balance purposefully so that when the channel opens, the sodium and potassium will flow based upon concentration gradients. \n\nFor the power supply, the neurons are bathed in it. They use glucose (and a ton of it too) to power themselves. They uptake glucose from the surrounding fluids and they create ATP. ATP is a molecule whose bonds are unstable and give off lots of energy when broken. ATP is used as a catalyst in biochemical reactions in order to give a cell energy. "
]
}
|
[] |
[] |
[
[]
] |
|
1k4fs0
|
what the hell is the deal with bronies?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1k4fs0/eli5_what_the_hell_is_the_deal_with_bronies/
|
{
"a_id": [
"cbl93de"
],
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"text": [
"They are fans of the show My Little Pony, similar to how Trekkers are fans of Star Trek and Browncoats are fans of Firefly. "
]
}
|
[] |
[] |
[
[]
] |
||
136668
|
If infrared is just another "place" on the spectrum that includes visible light, can something be painted infrared? Or is the "visible light spectrum" different in some way apart from the fact that we can only see that?
|
Also, if something had the "color" infrared, or ultraviolet, would it be invisible to us?
|
askscience
|
http://www.reddit.com/r/askscience/comments/136668/if_infrared_is_just_another_place_on_the_spectrum/
|
{
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"c7155cu",
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"text": [
"Yes. Although when you say \"painted\" you're defining the spectrum as what you can see. A blue object reflects blue light and absorbs light from all other colors in the visible spectrum. But a what you call a blue object may also reflect infrared light. So to an animal that has the ability to see some of the infrared spectrum, it's more of a blue-infrared color. We don't really have a name for that color because it's not particularly useful or convenient for us to discuss things in those terms. I can give you a common example, though: X-rays are also part of the light spectrum. Lead has the property of absorbing X-rays, your skin is X-ray invisible (clear), and your bones reflect X-rays. So in a way, to a hypothetical animal that only sees in the X-ray spectrum, your skin is like glass, your bones are black, and lead is like a bright X-ray screen. This is why X-rays cameras can see your bones against a lead screen.\n\nEdit: as TsuDoNihmh alluded to, this also assumes you're shining a light source that produces all wavelengths of ~~visible~~ light equally. Just as if you shined a blue light on a white object it would appear blue, you'd have to shine an X-ray light to see X-ray colors. \n\nAlso, I think I may have reversed lead/bone colors. Someone can correct me. ",
"You can certainly paint something infrared. [This](_URL_0_) youtube video shows a special type of coating that is opaque in the visible but reflective in the infrared. You can think of it as a type of infrared paint.\n\nSimilarly, it's possible for a material to be opaque in most frequencies but reflective in the UV. [This](_URL_1_) company seems to make a whole range of uv reflective coatings for optical experiments and industrial applications. These coatings would have an ultraviolet color.",
"OP, I'll answer your question in the most general sense.\n\nRadio waves and low frequency microwaves are generally emitted and absorbed by relatively large metal antennas.\n\nHigh frequency microwaves are generally emitted and absorbed by molecular rotations (i.e. a nitrogen atom gaining or losing energy by spinning around)\n\nInfrared rays are generally emitted and absorbed by vibrating molecules (i.e. a water molecule with the hydrogen and oxygen atoms moving relative to each other).\n\nVisible light rays are generally emitted and absorbed by electrons being emitted or absorbed by an atom, but staying within the molecule (i.e. moving back and forth between the valence and conduction bands)\n\nUltraviolet through X-rays are generally emitted and absorbed by electrons moving from a state that is deep, deep inside the valence band towards a state that is extremely energetic and far away from the valence band.\n\nSo when you're talking about \"paint\" that can color something within the electromagnetic spectrum, that \"paint\" has its limits depending on the positioning of its atoms and electrons. If it lets atoms and electrons move very easily, then it will absorb radio waves through infrared rays. If it keeps electrons locked up tight, then it will generally reflect visible light. If it keeps electrons locked up tight with many, many levels of other electrons blocking them, then it will absorb and possibly emit x-rays.\n\nSources: My plasma textbook and optoelectronic textbook."
]
}
|
[] |
[] |
[
[],
[
"https://www.youtube.com/watch?v=4uNyQW29xGA",
"http://www.spectraloptics.com/nbreflective"
],
[]
] |
|
25bovm
|
Was the Roman legal system the most modern and developed legal system during ancient times?
|
So many of our legal terms (Habeus Corpus, In forma paupis, ex post facto etc.) come from Latin, so certainly the Romans did something correctly, or the Roman legal system was just one of the best in its time?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/25bovm/was_the_roman_legal_system_the_most_modern_and/
|
{
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"chfpl4e"
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"score": [
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"text": [
"You're almost assuming that the derivation of western legal traditions in large part from Roman law was a conscious choice or decision over other alternate systems that were less \"developed\".\n\nIt's basically tautological, but the reason for the Latinisms in modern western legal language is simply that they were derived in part from Roman law. Legal traditions and systems generally don't emerge overnight or immediately, and even important watersheds like the Juris Civilis or the Code Napoleon are built on existing legal traditions.\n\nThis isn't because other legal systems or traditions were 'inferior' or 'less developed'. Modern Western legal systems might be said to be a mix of Germanic and Roman systems more than anything else.\n\nThere is also a problem with the idea of 'Roman legal system' - which one do you mean? Roman law was not some monolithic unchanging system that existed for a thousand years, and itself developed and changed over time. The image of Roman law given through say the Juris Civilis isn't necessarily reflective of Roman law or legal practice throughout Roman history, but a deliberately crafted rationalisation of Roman law created in the 6th century."
]
}
|
[] |
[] |
[
[]
] |
|
1nbr7b
|
why is it called "surfing" the web?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1nbr7b/eli5_why_is_it_called_surfing_the_web/
|
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"text": [
"Language left over from channel surfing on TV.",
"The internet is a series of tubes, thus it can be described as tubular. Tubular is an expression that was common among surfers in America during the 1980s. Case closed.",
"because it makes you wet",
"\"going net-surfing\" was coined in a June 6, 1991 comp.admin.policy post by Brendan Kehoe. \n\"...Here's a question: how do other people deal with users that they *think* \nare doing no-nos around the net? One of our users had the habit of \noccasionally going net-surfing and doing the hit-and-run type of \nattempts (trying 'guest' usually)...\"\n\nHe is known for authoring Zen and the Art of the Internet published back in 1992 as well."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
1uknyr
|
How "woman-friendly" was early Christianity, at least for its place and time?
|
I've heard that very early Christianity - in its first and second century iterations, before it became more mainstream - featured women in prominent leadership roles and generally gave women a higher "status" in the religion than later versions of Christianity did. I've even heard that members of other religions in the area referred to Christianity as a "women's religion," perhaps as a way of mocking it for the religious power it gave to its female members.
The problem is that I've never really seen good sources on it. There's some analysis on the translation of the Bible that *allows* for women having higher status, like the argument made [here](_URL_0_) by the Junia Project. There are also some women who are supposed to have leadership positions in the early church based on between-the-lines readings of the Bible, like Mary Magdelene (who was later described as a reformed prostitute, erroneously from my understanding), and more tenuously women like Phoebe and possibly Junia (who may not have been female?) who are described in language similar to other prominent disciples/apostles. I'm not sure how one is supposed to reconcile those examples with Paul's stated advice about the role of women in both homes and churches, however.
Basically, I'm wondering what the going opinions are among scholars about the place of women in early Christianity, and hoping for some scholarly (but reasonably accessible to a non-historian) sources I can look at to help me understand the issue further. I'm also curious to know how it compared to other religions of its day - and then, if there was a change at some point, where and how that came about.
Can anyone speak to this particularly?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1uknyr/how_womanfriendly_was_early_christianity_at_least/
|
{
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"Keep in mind that Paul's letters to Timothy were likely not written by Paul, but rather attributed to him long after he died. Paul's authentic letters are more radical (Galatians 3:28, \"There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus\"), the pastoral letters attributed to him are written decades later and are more supportive of the established social hierarchy. There are also later additions to authentic letters that do not appear to be written by Paul and serve the same purpose; by the second century the early Christian church was already pulling back from Paul's egalitarian writings.\n\nBesides the writings in the Bible, we also have a [letter from Pliny the Younger](_URL_0_) to the Emperor Trajan, written in 111-113 CE, indicating that two female slaves were deaconesses in the church.",
"Generally speaking, women went from an important supporting (not leadership) role in the Church to a subservient one, particularly in the West, by the fifth century.\n\nI have not read it in a while, but the book you want is\n\n* Madigan, Kevin, and Carolyn Osiek, eds. Ordained Women in the Early Church: A Documentary History. Baltimore: Johns Hopkins University Press, 2005.\n",
"So, I think it's important to note that Christianity being \"women-friendly\" should not be strictly identified with allowing women to be priests/deacons/whatevs. After all, the vast majority of Christians do not become priests and I worry that concentrating so much on the priesthood imports both modern notions about what constitutes \"proper\" gender roles and a clericalism which is, I don't think, not present during the time period (incidentally I don't think there's any real evidence that the ordination of women was ever widely accepted in the early Church). \n\nInstead, I think it's better to think about this question in terms of how Christianity understood the roles of women compared to the prevailing culture. This is a pretty complicated question, because we're talking about hundreds of years and a large empire and Christian opinion was never exactly uniform (nor, of course, was pagan thought). Thus, I'll be brief. I'd recommend Peter Brown's *Body and Society* for an excellent overview of Roman attitudes towards sex and gender in this time period, especially as it relates to sexual renunciation. Nicola Denzey's *The Bone Gatherers* is also a good source, although not a general survey it is written for a more general audience and very interesting (also, if you look closely in the acknowledgments there's an excellent young scholar, who happens to be a very handsome r/askhistorians poster in his spare time, who gets a shout out).\n\nOk, all that said, Christianity does seem to have appealed very much to women in the time period, for a variety of reasons. Perhaps one of the most important was that it allowed women to break free from the basic duties of the Roman women (i.e. get married, have as many babies as possible, try not to bleed to death during childbirth) by supporting institutions such as consecrated virgins and widows. This allowed women considerably more autonomy than was normal, and women were able to attain positions of considerable import within the Church. For examples, check out the correspondants of Jerome such as Macrina, fabulously wealthy women [allowed to keep their money, since Christianity allowed them to forgo remarriage] who founded monateries and were vital to the creation of the Vulgate. Also, see Ambrose's writings on virginity to see how prized virgins were by Church officials. There's also the character of the Christian mother facilitating her son's conversion, Monica and Helena being the most famous exemplars, which becomes a bit of a trope and is an interesting phenomenon in its own right (and I believe [although am less certain on this point) does not have an easy parallel in non-Christian writings of the time). \n\nI feel like this has become a bit scattered, but I hope I've shed some light. You may also want to check out early Christian hagiography and similar type texts, the sayings of the Desert Mothers, the life of St. Mary of Egypt, and especially the Acts of Paul and Thecla (which should be easy to find online with little effort). Thecla's life was both quite early and enormously popular, it's also a pretty fun read. Hope that helps! "
]
}
|
[] |
[
"http://juniaproject.com/phoebe-servant-or-minister/"
] |
[
[
"http://www.earlychristianwritings.com/text/pliny.html"
],
[],
[]
] |
|
3lhbo3
|
If you were standing on the surface of Pluto (or one of the outer planets), how much illumination would the sun actually provide for you to see with the naked eye?
|
I understand the outer planets are gaseous planets with no "surface," but I think you know what I mean.
Would it be like a night on earth with a full moon? No moonlight? Bright enough that daylight would be easily discernible from night?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3lhbo3/if_you_were_standing_on_the_surface_of_pluto_or/
|
{
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"text": [
"The amount of sunlight is decreases by a factor of roughly the square of the distance. So if you are 10 times further away the sun is 100 times dimmer. Pluto is over 30 times further away than the Earth is from the sun, so the sun is about 90 times dimmer than it is on Earth. \n \nThe thing is the Sun is very very bright, even at Pluto the noon day sun would be hundreds of times the brightness of the full moon. \nIn fact it would be roughly as bright as the lighting in most office buildings."
]
}
|
[] |
[] |
[
[]
] |
|
60xctc
|
what is poison?
|
Why does bug spray not kill humans? Why can some animals endure things that would kill humans? Does gasoline or bleach or overdose of medication kill you by the same mechanism as cyanide or strychnine or the 'vegetable alkaloids' from old murder mystery books?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/60xctc/eli5_what_is_poison/
|
{
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"text": [
"Really, a poison is something that will harm or kill you if taken into your body in an amount you're likely to encounter. Technically, water or caffeine (or anything) will kill you if you take enough of it, so that's why I added the \"in an amount you're likely to encounter\" part of it. \n\nSince your body is really just a very complicated series of chemical reactions all going on, there are lots and lots of ways to throw a wrench into things and, well, kill you. cyanide or carbon monoxide, for example, bind incredibly strongly to your blood cells and prevent them from carrying oxygen to your cells, starving them of energy.\n\nStrychnine binds to receptors on neurons that normally are for neurotransmitters. In particular, it causes your neurons to be triggered to go off more easily, which causes muscle spasms and death by asphyxiation.",
"A poison is a substance that causes negative physiological effects in an organism. The effects can be disruptice, harmful or even deadly. What makes something poisonous to an organism depends on the substance, the dose and the underlying physiology if the organism.\n\nFor example Grapes are harmless to humans but in cats, they will cause kidney failure."
]
}
|
[] |
[] |
[
[],
[]
] |
|
n63ht
|
why are there so many different electrical outlets in this world?
|
I just found [this](_URL_0_) on 9gag and was wondering.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/n63ht/eli5_why_are_there_so_many_different_electrical/
|
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"text": [
"I would say because there are so many countries. Theoretically, a mass summit could create a universal wall plug that countries could then opt into, but no one really has any incentive to do that. The economy will barely benefit from such a change, and might even take a dip, because all the people selling wall plug conversion kits will be out of a job. It's a wonderful idea in theory but only benefits end users. It's just like how cell phones have their own dongles everywhere, because each phone set manufacturer doesn't have a large enough incentive to conform to any standards",
"The Danish plug continues to look happy, while the North American plug continues to look stern and disappointed.",
"I would say because there are so many countries. Theoretically, a mass summit could create a universal wall plug that countries could then opt into, but no one really has any incentive to do that. The economy will barely benefit from such a change, and might even take a dip, because all the people selling wall plug conversion kits will be out of a job. It's a wonderful idea in theory but only benefits end users. It's just like how cell phones have their own dongles everywhere, because each phone set manufacturer doesn't have a large enough incentive to conform to any standards",
"The Danish plug continues to look happy, while the North American plug continues to look stern and disappointed."
]
}
|
[] |
[
"http://d24w6bsrhbeh9d.cloudfront.net/photo/944946_460s_v1.jpg"
] |
[
[],
[],
[],
[]
] |
|
1e0ydd
|
why is there so much media attention on the jodi arias case?
|
There has been some sort of coverage about it for weeks now. Why do so many people care about it?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1e0ydd/eli5_why_is_there_so_much_media_attention_on_the/
|
{
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"text": [
"America loves a killer. Bonus points for being a freak in the sack.",
"Attractive white girl + violent crime = media frenzy",
"My mother has kept me up to date with everything. It's fascinating to watch her behaviour and the theatrics of Martinez. I'm glad it's almost over. I'm sure it really boosted HLN'S network ratings, and they're probably scrambling to find something new to entertain viewers.",
"A pretty white girl who we got to see naked might get sentenced to death. ",
"You know what, it's so funny - I read the newspaper every single day, get news delivered to my e-mail, all of that stuff. And if someone put a gun to my head before maybe a week ago, I'd *never* have been able to say who she was or what she did. I have absolutely no idea how I missed the story. I feel like I'm the only person in the world who didn't know what the case was. It's like, what rock have I been living under? And then I see posts like this and discussions around the internet asking why there's so much attention on it, and my discomfort grows even worse.\n\n\nThe point is, people may care, but apparently not enough to make it sink into *my* thick skull."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
|
6ysomi
|
How the bloody hell did an old italic alphabet reach scandinavia and became the runic alphabet used by germanics ?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/6ysomi/how_the_bloody_hell_did_an_old_italic_alphabet/
|
{
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"text": [
"There is a large debate on the origin of runes. Simply because we do not know 'exactly when, where, why or by whom runes were first created' (Findell 2014:6). \n\nBarnes (2012: 9-10) lays out four basic points that runologists agree upon concerning the origin of runes: \n\n1. The oldest runic inscriptions are dated from AD c. 150-200 and one artefact, the Meldorf fibula from northern Germany, may have a runic inscription, but may also be roman is dated to around AD c. 50. \n\n2. 'The centre of earliest documented runic activity is the area that comprises modern Denmark, southern Norway and southern Sweden'. A small number have been found in northern Germany and eastern Europe. In addition, all of these finds have been on portable objects. This is important because it means that these objects are found far from the places that they have been discovered. \n\n3. Runes are part of the Mediterranean (phoenician-greek-etruscan-roman) alphabetic writing tradition. Runes are based on the same principles as these alphabets and 'number of runes are identical or virtually identical to characters in one or other, or several, of these alphabets (especially the roman and those of northern Italy, derived from Etruscan). They nevertheless shoe more than a little independence of the Mediterranean tradition'. For instance, the roman alphabet goes abc, runic alphabets go fuþark. \n\n4. Runes were certainly derived in an area of contact with but not part of the Roman empire. \n\nObviously, these points are not answers, but they provide guidance when evaluating proposals on the origin of runes. \n\nAs pointed out by Barnes (2012) the majority of runologists believe that runic and various Mediterranean alphabets cannot be due to chance (10). Cultures intermixed widely during this time period and it is reasonable to assume that Germanic script derives from Mediterranean script as Germanic speakers and those who spoke with southern European tongues interacted. The arguments emerge around which alphabet runes stem from and views have changed over each decade based on new evidence. I wish I could give you a more exciting answer than Germanic peoples thought writing was a good skill and brought it back home after their travels, but this is likely the case. \n\nI can attempt to explain some of the arguments if anyone is interested, but I am not a linguist or philologist, which are the field runology aligns more with. \n\nBarnes, M., P. (2012) Runes: A Handbook. Woodbridge: The Boydell Press. \n\nFindell, M. (2014). Runes. London: The British Museum. \n\nAlso, this is my first post. If I did anything wrong please let me know and I will correct it. "
]
}
|
[] |
[] |
[
[]
] |
||
4uaj4w
|
what exactly causes the sickly gross-tasting burps that occur after overeating?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4uaj4w/eli5what_exactly_causes_the_sickly_grosstasting/
|
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"text": [
"A pocket of air is always present in your stomach (and visible on a standard chest X-ray).\nWhen eating, some more air gets in through swallowing.\nThe stomach doesn't immediately empty itself when eating, so imagine all you have eaten starting to be digested by stomach acid and enzymes and floating in what you've drunk.\nSo, the air in your stomach normally comes out with burps, but it stayed in this bag full of nasty stuff for a while, so it takes its smell up and out.\nIt actually smells like vomit because it is vomit, it just doesn't come out.\nYou're welcome.",
"I think you're referring to sulfur burps, where it smells/tastes like rotten eggs?\n\nThey can happen for a number of reasons. Stomach infections can cause it, as can food poisoning. Or it can just come from eating a lot of fatty food."
]
}
|
[] |
[] |
[
[],
[]
] |
||
2a94fz
|
When referring to temperature, what exactly is a degree?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2a94fz/when_referring_to_temperature_what_exactly_is_a/
|
{
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"text": [
"Temperature is really a measure the average kinetic energy of the molecules. As they gain energy (heat) they tend to move around more. Degrees are a fundamental unit, meaning they aren't a product of other units like joules or watts. The different scales like Celsius, Fahrenheit, or Kelvin, are based of different experimental values or fundamental constants. ",
"The term \"degree\" simply means a standard (equal) unit of measurement between two given points. For example we (arbitrarily) assign 360 degree units to the circumference of a circle. It could just as easily have been 1000 or 100. This is useful for measuring angles as they are fractions of a circle.\n\nFor temperature the same is true. The Celcius scale has 100 degrees between the freezing/boiling points of water. The Farenheit scale has 280. Therefore the actual temperature change of one degree is a lot smaller in F than C.",
"An arbitrary unit of temperature from some reference point. Just like a kilometer is a unit of distance."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
35cyo2
|
why do my hands get clammy when i am afraid? evolutionarily shouldn't i increase my grip ability rather than losing grip with moisture?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/35cyo2/eli5_why_do_my_hands_get_clammy_when_i_am_afraid/
|
{
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"text": [
"When you're afraid, your body's processes speed up, especially ones that help you deal with stress. Most important in regulating your body under stress is temperature regulation, which is primarily handled by sweating.",
"I always remind people: evolution is a c- student. Evolution processes do just enough to help that species \"pass.\" ",
"Don't know why your hands get clammy in the first place, but clammy hands isn't as bad as you'd think.\n\nDamp palms are really only a slippery problem when you're using very wet palms to grip artificially smooth surfaces like metal. On most surfaces, such as dirt or wood or unpolished rock, slightly sweaty palms are actually stickier. ILLUSTRATIVE EXAMPLE: Run your hand on your forearm right now: if you're dry, your hand will slide smoothly. Now think back to a time you were a little sweaty: remember how disgustingly clingy your skin felt? Same deal.\n\nIt basically has to do with the hydrogen bonds in water. For example, adding a bit of oil to your hands will never* (*never say never) make them stickier, but adding water can. On natural/rough surfaces, the water can fill in the gaps between the object's texture and your skin texture. The water then kind of acts as a sealant and a glue, since water is naturally \"clingy\" due to hydrogen bonds.\n\nNot a very strong glue, but it can be effective enough. For example, \"damp palms\" is essentially the mechanism used by tree frogs for climbing. _URL_0_\n\nAlso, feel free to check out _URL_1_"
]
}
|
[] |
[] |
[
[],
[],
[
"http://rsif.royalsocietypublishing.org/content/3/10/689",
"http://en.wikipedia.org/wiki/Dispersive_adhesion"
]
] |
||
2mckub
|
how is blackberry still in business when no one uses one? i don't know a single person who still uses a blackberry.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2mckub/eli5_how_is_blackberry_still_in_business_when_no/
|
{
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"text": [
"How many people do you know? Let's be generous and say 500.\n\nThat's a rounding error on the population of the US. So your circle is probably not a great indicator.\n\nThere are a number of companies, organizations and agencies that had longstanding contracts with Blackberry. Many of them are working off those contracts as we speak but (for the time) they are still using them. \n\nIn addition, there are some number of people who prefer Blackberries. My understanding from them is that the physical keypad is a plus in their eyes.\n\nStill others haven't upgraded their phone in years because they either A) don't care too or B) don't feel like paying for it.\n\nSo Blackberry is hanging on by its fingernails... but it is still a company.",
"Blackberry is pretty big in foreign markets, and they have a lot of other innovative patents. Their patent portfolio is estimated between $2 billion and $3 billion",
"because people still DO use them. much of the corporate world, which is slow to change standards, standardized on them and is not about to throw out their blackberry enterprise servers and buy hundreds of new phones.\n\nmany have, but there is still a significant amount of holdouts out there.\n\nthey did damn near go under not to long ago, but found investors to keep them afloat.",
"Believe it or not in Latin America it's still very popular ",
"Pretty sure a lot of government agencies use them because of their security features."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
8qvg94
|
is there an architectural advantage to “the pentagon” building being shaped as a pentagon? like does it provide more security, or is it simply for aesthetics?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8qvg94/eli5_is_there_an_architectural_advantage_to_the/
|
{
"a_id": [
"e0mc2ay",
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],
"score": [
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29,
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"text": [
"It would be cool if there was an amazing architectural advantage to the shape. The truth, as truth often is, is spectacularly boring and ordinary.\n\nThe simple truth of the matter was that the land that the government purchased for the new military headquarters was [pentagonal in shape.](_URL_0_) The building was designed to make the most use out of the land.",
"It's a fascinating story. The book Pentagon a History by Steve Vogel goes into it in detail. The idea was to build a building for the War department with a lot of square footage without exceeding the low building height limits of the District of Columbia. The original location was a rectangular space with one corner cut off by a river. They made plans for this location, essentially a building that completely covered the lot. Then they found that the ground wasn't strong enough to hold up the building. They moved locations, to the present site, and wanted to make up the time. Since the plans for the other site had: chunks of building that were straight, chunks of building that met at a 108˚, and chunks of a building that met at 90˚; they asked what shape could they make without redrawing those plans. It turns out you can make a regular pentagon shape that has more area inside than a square shape. Those are essentially the only shapes you can make without drawing plans for a different kind of corner. So, they reused the shapes to make the present building.",
"The original location was the [Arlington farms](_URL_0_) that is like a uneven pentagon and size limitations for the building so it had the shape of a uneven pentagon. The Arlington farms is today a part of the Arlington National Cemetery.\n\nThe location was changed and the size was not limited the same way but the same planes was used because it was during WWII and it was needed as soon as possible.\n\nThe design had som limitation like 4 floors so not to block the view and steel used was limited and it had to be a quick build.\n\nIf you look at [this image](_URL_1_) you can see the if exactly in the original location.\n\n\n"
]
}
|
[] |
[] |
[
[
"http://www.washingtonpost.com/wp-dyn/content/graphic/2007/05/24/GR2007052400817.gif"
],
[],
[
"https://en.wikipedia.org/wiki/Arlington_Farms#/media/File:ArlingtonFarmsAerialPhoto1949.png",
"http://www.washingtonpost.com/wp-dyn/content/graphic/2007/05/24/GR2007052400817.gif"
]
] |
||
5bnutf
|
how are amazon third-party book vendors able to offer new and recently-published books in "new" or "like new" condition so quickly?
|
A book's publication date was set for today, Mon. Nov. 7th. Third-party booksellers on Amazon have already started selling the book for a few dollars below the Amazon price for the book, in new / like new condition. How do they do this?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5bnutf/eli5_how_are_amazon_thirdparty_book_vendors_able/
|
{
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"text": [
"In general, many third-party booksellers on Amazon used automated programs to handle their inventory. Some of them simply have the computer programmed to update when they receive new inventory, and thus those booksellers may have received their shipments of that new book today and thus immediately updated their listings on Amazon accordingly.",
"Some of these sellers are actual bookstores (on the street or online). They get access to new books from the publisher at the same time Amazon does.",
"They are lying about availability, and I can (kind of) prove it with a simplified example.\n\n[This](_URL_0_) is an Amazon link to a manual for a calculator app that's available for Window. I'm very familiar with it because I wrote both the app and the manual. According to Amazon, there are 3 used and 8 new ones available from third party sellers.\n\nExcept that exactly zero copies have been sold. There are no used copies available anywhere in the world.\n\nThe other sellers are pretending to have stock, but they don't. If you order from them, they will simply buy a copy and send it on, adding their own handling charges as a way to make money.\n"
]
}
|
[] |
[] |
[
[],
[],
[
"https://www.amazon.com/BC-BASIC-Reference-manual-tutorial/dp/1517450675/ref=sr_1_1"
]
] |
|
199l3w
|
Does the speed of light apply as a limit to how fast something can rotate?
|
I have wondered this for a while: is there an upper limit on how fast something can rotate, similar to nothing being able to travel from A to B faster than c? Or is this a silly question?
|
askscience
|
http://www.reddit.com/r/askscience/comments/199l3w/does_the_speed_of_light_apply_as_a_limit_to_how/
|
{
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"text": [
"There's no limit on angular velocity, but there is a limit on tangential velocity at any point on a rotating body. So if something has a relatively small diameter, it can rotate very fast. However, if you start looking at rotation of very large (planet-scale) objects, where the outer edges would be moving at relativistic velocities, you'll find that the tangential velocity at any point can never exceed the speed of light, and getting any part of a giant wheel to these velocities would require massive amounts of energy.",
"When I read your question I immediately thought about pulsars, which are neutron stars that can rotate at hundreds of Hertz. They are probably as close as you can get to macroscopic relativistic rotators.\n\nA rudimentary calculation of tangential speed (assuming uniform rotation and spherical shape) at the equator of a pulsar:\n\nTaking a typical radius (c.f. Crab pulsar) of R= 5 km, frequency of 700 Hz (on the larger side, observationally).\n\nv = 2π R f ≈ 0.07 c\n\nSo very fast pulsars can barely start approaching the relativistic regime, conventionally taken to be when v > 0.1 c"
]
}
|
[] |
[] |
[
[],
[]
] |
|
fcu7ak
|
Humans seem to have a universally visceral reaction of disgust when seeing most insects and spiders. Do other animal species have this same reaction?
|
askscience
|
https://www.reddit.com/r/askscience/comments/fcu7ak/humans_seem_to_have_a_universally_visceral/
|
{
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"Actually, elephants avoid bees. Whether or not it’s disgust in particular would be difficult to decipher, but it has been useful in creating natural barriers for the animals to keep them away from crops while giving the farmers another valuable crop. \n\n\n_URL_1_\n\n\n_URL_0_\n\n\n_URL_2_",
"Idk about insects but primates do share an inherent fear reaction to snakes. This is thought to be because in the trees you can escape most predators on the ground, but snakes can still get you and the often look like vines. Especially true for our ancestors like ardipithecus because they were a lot smaller than modern humans.",
"Well this isn’t true. People eat insects and spiders in many cultures. I work in the Amazon and insects often make great meals. There are even important times of year where insects are the main staple.",
"Phobias are difficult in that they can be innate or they can be learned. It's easier to prove a learned phobia because people can become highly sensitized to something like spiders. Whereas a person might have been able to be in a room with spiders previously, that same person can become irrationally afraid of spiders because of a traumatic event.\n\nThat's easier to track or prove than a phobia which seems to have always been in place. For example, we humans seem to be calibrated to be phobic to certain situations to a greater or lesser degree across a population. A person's fear of heights is understandable and, we assume, has a purpose. It keeps us safe from falling. However, why don't we all have this fear to the same degree? Some people have it a little and some to an intense degree. It's easy to speculate about this in terms of evolution, but we don't really have proof. You could say, a healthy fear of heights would make us climb to safety, but keep us in the lower branches where we might be safe should we fall. Humans without an intense fear of heights might climb higher and be safer from predators; however, they would be at greater danger of falling, but lesser danger of predators. And, in fact, phobias don't seem to be at the same level even among the same family. So, one possible explanation is that our phobia intensity is spread out to put us at varying degrees of caution and therefore varying distances from a threat. \n\nOne weird clue to phobias being innate is how weird they can be and how young they can become apparent. Young children can have phobias that don't seem to have any root in experience. This isn't weird in itself; however, the focus of fear is. Children can be afraid of something as innocuous as buttons. The fear of buttons is a known phobia. And if young children have it, why? This isn't just a sensory thing. The buttons don't have to be actual clasps. They can simply be decorative buttons or merely lying on a table and the child will refuse to wear the piece of clothing with the button on it. So, is the fear innate. And if it's innate and written into our DNA, why? Is it random? Or do buttons look like something we would have been well served to stay away from? Is the phobia related to ticks? Or is it again a calibration issue? Does a button look like a button to most people yet look just enough like a spider that that phobic group interprets it as a spider? It's really difficult to discern.",
"Firstly, there are plenty of people who don't have a \"visceral reaction of disgust\" to insects and spiders. Some cultures regularly eat many arthropods. Qualifying it as universal is incorrect.\n\nSecond, many animals will gladly eat insects and spiders without hesitation even if they aren't their usual prey, so I'd have to go with no. A large percentage of smaller animals subsist mainly on such prey in the wild and in captivity.",
"Entomologist here. I think a lot of folks can disagree on the insect comment in my profession.\n\nIronically though, there was an article in the American Entomologist I need to track down again. Basically entomologists we’re polled, and a lot really didn’t like spiders. If I remember right they were mostly perfectly fine with six-legged critters, but eight-legged discomfort was about as high as the general public.",
"A lot of disgust is a learned behavior. For example a baby will eat its own poo given the option and means tondo so. They learn the disgust, usually, from watching the person changing them. I can't think of any disgust that is instinctual, at that point you might be thinking of fear which is a different matter I think",
"Not sure about insects, but a study has shown that there is some correlation between the development of highly-advanced vision in primates and the amount of deadly snakes present in the areas they developed. This is known as Snake Detection Theory.\n\n\n\n_URL_0_\n\nThe study suggests that part of the longevity of primate species is due to our evolving a highly-specialized threat detection system through our vision. It explains why primates evolved vision that is second only to birds of prey, instead of other senses (such as smell) that are a lot more common to be found highly-developed in other animal species.\n\n > \"The present study shows preferential activity of neurons in the medial and dorsolateral pulvinar to images of snakes. Pulvinar neurons responded faster and stronger to snake stimuli than to monkey faces, monkey hands, and geometric shapes, and were sensitive to unmodified and low-pass filtered images but not to high-pass filtered images. These results identify a neurobiological substrate for rapid detection of threatening visual stimuli in primates. Our findings are unique in providing neuroscientific evidence in support of the Snake Detection Theory, which posits that the threat of snakes strongly influenced the evolution of the primate brain. This finding may have great impact on our understanding of the evolution of primates.\"",
"This doesn't address your question directly, but there is a Hidden Brain (a behavioral science podcast) episode that deals with the topic of disgust. I found it fascinating, and if OP's question is interesting to you, this is a must-listen. There's a [transcript](_URL_0_) as well, if you'd rather read it.\n\n[_URL_1_](_URL_1_)"
]
}
|
[] |
[] |
[
[
"https://www.smithsonianmag.com/smart-news/how-scent-angry-bees-could-protect-elephants-180969777/",
"https://www.sciencemag.org/news/2010/04/elephants-have-alarm-call-bees",
"http://elephantsandbees.com"
],
[],
[],
[],
[],
[],
[],
[
"https://www.pnas.org/content/110/47/19000"
],
[
"https://www.npr.org/transcripts/597129490",
"https://www.npr.org/2018/03/26/597129490/crickets-and-cannibals-unpacking-the-complicated-emotion-of-disgust"
]
] |
||
i45zf
|
How can i make colored fire?
|
I saw this on a tv show on g4 one day and it blew my mind.
|
askscience
|
http://www.reddit.com/r/askscience/comments/i45zf/how_can_i_make_colored_fire/
|
{
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"c20r7s2",
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4,
2
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"text": [
"Different chemical elements burn with different coloured flames. \n\nSee: [Flame tests](_URL_0_)",
"The other two posters got it right. My favorite metals to burn are [copper](_URL_0_) and [barium](_URL_2_), and [calcium](_URL_1_) is really cool too. My undergrad chemistry lab final basically consisted of lighting a bunch of different solutions on fire and using the color of the flame to identify the metal. Chemistry is awesome."
]
}
|
[] |
[] |
[
[
"https://secure.wikimedia.org/wikipedia/en/wiki/Flame_tests"
],
[
"http://www.flickr.com/photos/37388341@N00/7898207/",
"http://www.flickr.com/photos/37388341@N00/1490582001/",
"http://www.flickr.com/photos/37388341@N00/1490598805/"
]
] |
|
sdams
|
A question about the Gestapo secret police of Nazi Germany
|
Were the Gestapo very active in the policing of the people or was it more the SS? Or who was it if neither? I'm writing a 6 page research paper about how the people of Germany were controlled by Hitler through different so and any little tidbits of info could help also.
Thanks
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/sdams/a_question_about_the_gestapo_secret_police_of/
|
{
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2
],
"text": [
"The [Ordnungspolizei](_URL_1_) was responsible for most of the day-to-day police duties during the war, and that article suggests that they took on other duties as well, such as fire fighting. The [Kripo](_URL_0_) served as the civilian detectives, but I believe they worked closely with the SS and the Gestapo to investigate and prosecute not only crimes, but also political dissidents and similar things.",
"The average German (assuming he/she wasn't marked as a political criminal or a Jew, gypsy, etc.) had very little interaction with the Gestapo and even less with the SS who were part of military actions and deployed in most cases.\n\nThere was never the SS presence in the streets that you saw in Poland or occupied territories. The deportation of undesirables was handled with //more// discretion in Germany, so as not to alert the populate to what was actually going on. That said, Hitler made great use of large military rallies to remind the German people who was in charge."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Kriminalpolizei",
"http://en.wikipedia.org/wiki/Ordnungspolizei"
],
[]
] |
|
47e7wr
|
why are most cities "downtown" sections really shitty when they're usually a popular
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/47e7wr/eli5_why_are_most_cities_downtown_sections_really/
|
{
"a_id": [
"d0c9mcl"
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"text": [
"Maintenance of a downtown area is a tremendous undertaking. For example, repairing the streets could mean closing down the street for days and days. Colossal traffic jam, redirecting bus routes, businesses on that street pissed off, etc. It's very expensive and difficult. Due to the location, it gets tons of car and foot traffic so maintenance is needed more often. With millions of people going through the downtown area throwing trash everywhere and generally be slobs, there just isn't the ability to pick it all up. Uptown neighborhoods generally are kept much nicer."
]
}
|
[] |
[] |
[
[]
] |
||
8ad5be
|
Why can you refuel a plane mid-flight, but you can't refuel a car while it's running?
|
askscience
|
https://www.reddit.com/r/askscience/comments/8ad5be/why_can_you_refuel_a_plane_midflight_but_you_cant/
|
{
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"text": [
"You can refuel a car while it's running.\n\nThe difference is that most filling stations are not designed to refuel a car while it's running.\n\nIn an airplane, if it's running, refueling happens while the plane (or its props/jets) is in motion, meaning any fuel vapor gets blown away from the plane.\n\nIn a car, refueling generally happens on the ground in a gas station with a whole collection of stationary cars. Any fuel vapor sits in the air where it can be ignited by the engine, static electricity, someone's cell phone ringing, a cigarette, etc.\n\nSo people are asked to turn off their vehicles while at a gas station to minimize risk.\n\nA car runs just fine with the gas cap off the tank, which means it'll run just fine if you're adding new fuel to the tank.",
"You can absolutely refill a car while it's running.\n\nAdmonishments to turn off your car while fueling are generally due to one of two situations:\n\n-A running car in theory presents a fire or operational hazard, as if the car were to be put in gear it could propel itself forward and pull the breakaway hose out of the pump; \n\nor,\n\n-Removing the fuel cap on a pressurized system (e.g. your fuel tank) may result in a check engine light as the evaporative emissions system sees a sudden drop in pressure.\n\nThat being said, while prudence dictates that you turn off the engine while refueling there's no operational reason why it would be required. ",
"You can even refuel a car [while it is driving](_URL_0_). It was modified a bit to make it easier, however.",
"First of all most planes cannot be refueled mid-flight. A few military planes can. The reason is of course to be able to fly longer missions without landing - as airbases may not be available. [Operation Black Buck](_URL_0_) is a good example of this.\n\nBut for cars, there's no pressure in that direction. It is **trivial** to develop technology to refuel a car while driving. But there's no reason to. It is more expensive than pulling over, and most people have no problem with stopping every 500km for refueling. So noone wants to pay for that development.",
"Of course you can...why the hell would you want to? \n\nYou can just pull over to the side of road. One method is safe, one method is extremely risky.\n\nIn the case of aircraft, in-flight refueling is useful when you can't simply land the aircraft. For example if you're over the ocean, or there aren't any air bases within a reasonable distance. This generally isn't done outside of military air missions.\n\nIt was originally developed in the cold war as a way to allow american nuclear armed bombers to patrol outside of Russian airspace for days at a time. This allowed round-the-clock patrols using fewer total aircraft and fewer warheads. (The cost of the weapons was probably the most expensive part of the proposition.) Later on, ballistic missiles made the bombers redundant, but IFR was still useful as a way to allow fighter jets to patrol the airspace of a combat area, fully loaded, for more than 1-3 hours.\n\nFor land vehicles, there's no reason not to simply stop by the side of the road."
]
}
|
[] |
[] |
[
[],
[],
[
"https://www.youtube.com/watch?v=mE4Y7swUZyw"
],
[
"https://en.wikipedia.org/wiki/Operation_Black_Buck"
],
[]
] |
||
zu453
|
Why did Truman perform better in suburbs than cities?
|
In one of my classes today we were talking about polling, sampling, ect. Of course, one of the classic examples of poor polling was Dewey Beats Truman. According to my Professor, the reason for this blunder was because polling was over sampling cities, not accounting for the demographic shifts of the time.
My question is, wouldn't the demographics left in cities be more sympathetic to Truman?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/zu453/why_did_truman_perform_better_in_suburbs_than/
|
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"text": [
"The easiest way to answer that would be to say that the parties in 1948 were not the parties you know today.\n\nBoth parties had a liberal wing and a conservative wing. Dewey was from the northeast, the liberal wing of the Republican party, and a lot of the issues he was running on were basically expanding parts of the New Deal. That alienated conservatives from both parties, but especially caused him to lose support among Republicans - it did gain him some support among independents, which is probably one of the contributing factors in the skewed polling data.\n\nTruman was probably center-right among Democrats at the time, but I suspect his appeal to rural and suburban voters had more to do with personality. He was a midwesterner, grew up a farmer, was plain-spoken, direct, blunt, and engaged. This is \"Give 'em hell, Harry!\" and \"The buck stops here.\" Harry Truman. This was a major contrast with Dewey, who was rich, distant, intellectual and vague.",
"People understood that the New Deal and G.I. Bill created the surge of post-war expansion into the suburbs.\n\nThe people abandoning the cities for suburbs amounted to a significant expansion of the population just outside the cities. This shift had just started by the 1946 elections but was well underway by 1948.\n\nSample the population based upon the 1940 census and you over represented the old demographic and missed the new one (which shows up in the 1950 census)."
]
}
|
[] |
[] |
[
[],
[]
] |
|
1wrt1b
|
How do we decide which stars are important enough to name?
|
How do we decide which stars are important enough to name? There's such a huge number, what is the criteria for deciding which ones to focus on?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1wrt1b/how_do_we_decide_which_stars_are_important_enough/
|
{
"a_id": [
"cf4xclh"
],
"score": [
5
],
"text": [
"Most of the names are historical, and the modern convention is not to assign names to newly discovered stars. This [wikipedia article](_URL_0_) and some of the others it links to give a pretty good discussion."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Star_designation"
]
] |
|
2lmde9
|
why, when i eat terribly (pizza, cookies, chips, beer, etc) can i eat a lot, but when i clean diet, i get so full and 2k calories is hard to get each day?
|
Srsly--I can put down 1.5 Little Caesar Hot-n'-readies and a sixer of Coors Lite, but now, after 3 weeks of clean eating, 1 gallon of water a day, and exercise 4 times a week, getting my 2,000 calories is SO filling and eating takes WORK.
< ---'Merican
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2lmde9/eli5_why_when_i_eat_terribly_pizza_cookies_chips/
|
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"Define \"clean eating.\" I know a lot of people that cut back on junky, carb-heavy foods and are much less hungry. It has to do with your insulin spikes and resulting hormone suppression (leptin mostly) that keeps you from being mega-hungry. Also, if you're replacing your diet with lots of vegetables, they are much less calorie dense than junk food, so you are also getting physically full on less calories.\n\nEdit: spelling",
"**Caloric density** (the ratio of calories to the weight of the food). \n\nCarbohydrates have around 4 calories per gram; proteins also have around 4 calories per gram; and fats have around 9 calories per gram. \n\nWhen you eat \"clean\" foods, you are generally eating foods that have a low caloric density, but that is not all. These foods often also contain a higher amount of fiber, which increases the feeling of fullness (this is called *satiety*). These \"clean\" items are usually less processed foods containing unrefined carbohydrates, which take a bit longer for your body to digest. This means you feel fuller for longer.\n\nWhen you eat \"dirty\" foods, you are generally eating foods that have a high caloric density. These foods are often heavily processed with more refined carbohydrates, meaning your body can digest it quicker. That means you don't stay full for much too long.\n\nSometimes we mistake the feeling of thirst for hunger, and eat a snack when we could've been satisfied with a glass of water. The next time you feel hungry, try drinking a full glass of water and waiting a few minutes. You'll see that sometimes it's just thirst.",
"A lot of it is evolutionary - back before commercial food production, high-energy fats and sugary carbs were very difficult to come by and encouraged you to eat as much of them as possible. How? They tasted great, and still do. \n\nWe haven't evolved enough for our body to tell us 'stop, that's enough' because the more weight we put on, the less the consequences were of not knowing where our next meal came from. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
2bm2xo
|
is there a possibility in the future for full immersion virtual reality gaming?
|
I'm very excited about the Occulus Rift but it got me thinking and I began to wonder if there was a possibility for VR gaming that is fully immersed (you have sense of sight, smell, touch, etc).
Sort of like you would be able to log in and just sit down in a chair for a few hours but in the VR you would be fully functional.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2bm2xo/eli5_is_there_a_possibility_in_the_future_for/
|
{
"a_id": [
"cj6nboo"
],
"score": [
2
],
"text": [
"Anything is possible, someday, as long as that thing doesn't violate fundamental physical laws. And even then, who knows.\n\nPractically though, yes, this is reasonable some day. One of the critical aspects here for experiencing this \"just [sitting] in a chair\" is the ability to plug our brains directly into computers.\n\nThis is still a very new thing, but we're getting better at it all the time. Cochlear implants (_URL_1_) do this, and there's a ton of new research that's very promising on doing stuff like plugging limbs directly into our nervous systems (_URL_0_).\n\nOf course, none of this is even close to providing a fully realized experience through a wire, but we're starting to make the first baby steps on that path.\n\nAlso, this is a work of FICTION, but if you find this topic cool I highly recommend the book Ready Player One.\n\nEdit: Some links."
]
}
|
[] |
[] |
[
[
"http://www.wired.co.uk/news/archive/2013-05/31/darpa-touch-sensitive-prosthetic",
"http://en.wikipedia.org/wiki/Cochlear_implant"
]
] |
|
15sxsp
|
The closest star to earth is 4.3 light years away. Is this par for the course in the Milky Way?
|
Basically, is our cosmic neighborhood crowded, isolated, or about average
|
askscience
|
http://www.reddit.com/r/askscience/comments/15sxsp/the_closest_star_to_earth_is_43_light_years_away/
|
{
"a_id": [
"c7pip78"
],
"score": [
5
],
"text": [
"The density of stars decreases as you move away from the galactic centre. There, stars are much closer together."
]
}
|
[] |
[] |
[
[]
] |
|
2hjvzf
|
why can't we make a system similar to a human body that gets energy from food?
|
For example instead of running cars on gas, we would put cheese and bread in the car to run.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2hjvzf/eli5_why_cant_we_make_a_system_similar_to_a_human/
|
{
"a_id": [
"cktbxx1",
"cktc1es"
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"score": [
2,
2
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"text": [
"We could do that. We don't because it would be horribly inefficient compared to the fuels we already use, or most of the alternatives we've already devised.",
"They exist already. They're called horses.\n\nIn fact, the reason the term \"horsepower\" came to exist was because some of the first steam engines were intended to replace horses that were being used to drive pumps to get water out of coal mines. And they *did* replace them, because even the 18xx steam engines were better than horses."
]
}
|
[] |
[] |
[
[],
[]
] |
|
2s7b9s
|
Is physical information within our universe finite?
|
Bonus question: Is information (in all forms) finite?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2s7b9s/is_physical_information_within_our_universe_finite/
|
{
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"cnmu0cz"
],
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"text": [
"According to (quantum) information theory, the answer to both questions is yes, since \"[information is physical](_URL_0_)\", as [Rolf Landauer](_URL_1_) puts it in the linked paper.\n\nSince there is only a finite amount of matter in the observable universe, there can only be a finite amount of information. (Naturally, nothing can be said about the whole universe, unless one day we learn more about its nature.)"
]
}
|
[] |
[] |
[
[
"http://cqi.inf.usi.ch/qic/64_Landauer_The_physical_nature_of_information.pdf",
"https://en.wikipedia.org/wiki/Rolf_Landauer"
]
] |
|
a1b9x0
|
how does online banking work without the exchange of actual money?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a1b9x0/eli5_how_does_online_banking_work_without_the/
|
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"text": [
"When person A pays person B, the bank takes money out of A's account and deposits it in B's account.\n\nIf they use two different banks, the banks cooperate through a very elaborate digital money transfer system.",
"Most (if not all) banks don't keep everyone's full accounts available in cash; a lot of times they invest it into expanding their business and infrastructure or in various markets to make the money grow. So when the new bank \"receives the money\", it's still on their books, but they don't necessarily physically have it and don't physically need it. ",
"Most money is never actually physical money. When you get paid direct deposit, your money is not physical cash it just stays electronic. It’s just a number on a screen with codes and data that keep it secure and correct. Only when you choose to take out cash does your money become physical legal tender that you can touch or carry in your hands."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
g1d5ij
|
how does game streaming service (geforce now, stadia) have little to no lag, while traditional remote desktops (chrome remote desktop, microsoft remote desktop etc) having significant lags?
|
Just tried out GeForce Now and amused by its little latency.
But when I tried a traditional remote desktop (Phone to PC in a local network, so should eliminate the internet bandwidth problem), the lag is more significant than GeForce Now.
I wonder is it the underlying technology is different?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/g1d5ij/eli5_how_does_game_streaming_service_geforce_now/
|
{
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"text": [
"Whatever remote desktop program you're running has to render *and then* encode the video feed of the desktop on the computer that you're connecting to. The encoding takes a little bit of time. That little bit of time, combined with the fact that most remote desktop programs are just really quickly slapped together without any optimization means that you get a bit of lag.\n\nGeForce Now and Google Stadia are optimized to the point that they've gotten rid of the lag involved in encoding the source video. One of the likely ways that they've done that is by running the server on a custom operating system or drivers that is set up to render video into an encoded format for streaming - essentially encoding the video for \"free\" from a computation standpoint rather than requiring a second process to do it."
]
}
|
[] |
[] |
[
[]
] |
|
j4t0f
|
For lack of a better way to put it: What "sets" the speed of light?
|
I know that asking "what can go faster than the speed of light?" doesn't really make sense but I have always wondered on why *c* actually is...
It's proving very awkward for me to word. To try and put it another way: I've always assumed that the speed of light was due to the nature of the photons which are travelling at that speed but then I learned that gravity propagates at *c* too.
Is the speed of light an immutable physical law which is inherent in the fabric of our universe (is it like asking why the other "universal constants" are the value which they are?), which seems to explain to me why it's a "constraining factor" for several different phenomena, or is there another reason *why* the speed of light is *c*?
I apologise if this has been asked before. I did do a search but couldn't find too much.
edit: Thank you for the responses! They have been illuminating!.... Please also forgive this terrible, awful pun.
|
askscience
|
http://www.reddit.com/r/askscience/comments/j4t0f/for_lack_of_a_better_way_to_put_it_what_sets_the/
|
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"text": [
"The speed of light is actually the speed of an electromagnetic wave. The phrase *electromagnetic wave* is quite common but what does it actually mean?\n\nAn electromagnetic wave is a wave that is spawned when a charge is accelerated, not just moving, but accelerating. The reason an em wave is caused by this is because causing a charge to accelerate in turn makes that charge produce a *changing* electric field.\n\nThis changing electric field in turn induces a changing magnetic field. This changing magnetic field in turn induces a changing electric field, and the pattern continues. This discovery was made by Maxwell, who was able to discover that a changing magnetic field induces a changing electric field and vis-versa.\n\nNow that you have a brief understanding of a em wave, you can understand why the speed of light is what it is.\n\nBut first let me introduce two universal constants. The electric constant, known as \"permittivity of free space,\" and abbreviation with the Greek symbol for Epsilon then a subscript 0 (not sure how to post the symbol here), is bascially the strength of the electric force, the force that causes protons and electrons to attract to one another.\n\nThe second constant I will breifly explain is the \"Permeability of free space\" (abreviated with the Greek symbol mew). This is the strength that a magnetic field has in our universe.\n\nNow to bring everything together:\n\nIf you were to do the calculation of accelerating an electron you would find that there is some velocity V that the wave that this electron produced must move at. And when it is broken down you will find that this V is always equal to exactly 1 divided by the square root of the permittivity of free space times the permeability of free space.\n\nThis calculation was first made by Maxwell himself and he found that this simple calculation of V equaled the already measured speed of light when he discovered this. Therefore the speed of light is 1/Sqrt(Mew X Epsilon0)",
"this might help you. read robotrollcall's explanation.\n\n_URL_0_",
"I think you're asking why c is 3 x 10^8 m/s as opposed to some other value.\n\nThere's two answers. First, why that number - that's just units. It's 1 in natural units, 3 x 10^10 cm/s, and all sorts of other values in other unit systems.\n\nI think what you're getting at, though, is the question \"Why do massless things travel this far (gesturing with hands) in this much time (pauses and counts out some time) as opposed to that far (different gesture)?\" There's no reason that we know for that. It's just a fundamental constant of the universe. Given our laws of physics, we don't know a reason for c to take the particular value that it does, just that it has to have some value.\n\nYou might be able to draw in some anthropic arguments about it, but that'd be pretty sketchy, I think.",
"I'm not too impressed with any of the answers so far. I did a ctrl+'f' on electric permittivity and magnetic permeability and got nothing. Without getting too deep, let me see if I can break this down for you.\n\nA photon is an packet of electromagnetic energy. It propagates through space as a packet of waves (you can think of different \"perfect\" sinusoidal waves, each with varying intensity, travelling together through space adding up to some spatial volume of energy). This EM energies propagation through space is governed by wave equations. The speed of propagation is found to be constant with respect to frequency of the individual waves in free space and is found to be c. What is c, well it's equal to 1/sqrt(e u). Where e and u and the electric permittivity and magnetic permeabvility. What are these? Think of them as the amount of energy stored per unit volume in electric and magnetic fields for a given electric and magnetic field existing in that volume. As a wave propagates (say to the right), it needs to \"charge up\" (with energy) that space to the right, the higher the permittivity or permeability, the more charging/energy is required, the slower the wave will propagate.\n\nI'm not really sure you'll get that, but I thought I'd give it a shot without spending too much time editing and making it clearer.",
"The speed of light is actually the speed of an electromagnetic wave. The phrase *electromagnetic wave* is quite common but what does it actually mean?\n\nAn electromagnetic wave is a wave that is spawned when a charge is accelerated, not just moving, but accelerating. The reason an em wave is caused by this is because causing a charge to accelerate in turn makes that charge produce a *changing* electric field.\n\nThis changing electric field in turn induces a changing magnetic field. This changing magnetic field in turn induces a changing electric field, and the pattern continues. This discovery was made by Maxwell, who was able to discover that a changing magnetic field induces a changing electric field and vis-versa.\n\nNow that you have a brief understanding of a em wave, you can understand why the speed of light is what it is.\n\nBut first let me introduce two universal constants. The electric constant, known as \"permittivity of free space,\" and abbreviation with the Greek symbol for Epsilon then a subscript 0 (not sure how to post the symbol here), is bascially the strength of the electric force, the force that causes protons and electrons to attract to one another.\n\nThe second constant I will breifly explain is the \"Permeability of free space\" (abreviated with the Greek symbol mew). This is the strength that a magnetic field has in our universe.\n\nNow to bring everything together:\n\nIf you were to do the calculation of accelerating an electron you would find that there is some velocity V that the wave that this electron produced must move at. And when it is broken down you will find that this V is always equal to exactly 1 divided by the square root of the permittivity of free space times the permeability of free space.\n\nThis calculation was first made by Maxwell himself and he found that this simple calculation of V equaled the already measured speed of light when he discovered this. Therefore the speed of light is 1/Sqrt(Mew X Epsilon0)"
]
}
|
[] |
[] |
[
[],
[
"http://www.reddit.com/r/askscience/comments/fjwkh/why_exactly_can_nothing_go_faster_than_the_speed/"
],
[],
[],
[]
] |
|
d0orqm
|
Why did savory pie culture (shepherd's pie, chicken pot pie, etc.) not transfer to North America nearly as well as desert pie culture (apple pie, blueberry pie, etc.) while by comparison it thrived in Europe?
|
*Dessert
Also the question is about savory pies vs. sweet pies not exclusively chicken pot pies. I get that it wasn't the best example since it is popular across the US but that doesn't mean savory pies as a whole are when compared with their sweet counterparts.
As u/ThomasTTEngin pointed out, a potential addition to this question could be
"the fact that meat pies transferred extremely well to Australia, another British colony, and fruit pies far less so."
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/d0orqm/why_did_savory_pie_culture_shepherds_pie_chicken/
|
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"As usual, I'm here to suggest you cross-post this question to /r/askfoodhistorians which isn't quite as well-known but has a much more focused subscriber base.",
"The short, simple answer to your question is that savory pies are very popular in the US, just maybe not in the part of Florida you live.\n\nAside from the much more well-known chicken pot pie, you also have the good ol' Natchitoches meat pie (which is actually one of the official state foods of Louisiana), and the French-Canadian meat pie popular in Quebec and New Brunswick. Also, depending on whether you define the Caribbean as North America or not, there are also Jamaican beef patties - which are also very popular here in NYC - and an array of empanadas from all across the Spanish speaking portions of the continent. And these are just a few - I'm certain that there are plenty of others in regional cuisines that I am overlooking.\n\nSo, the better question is not why are savory pies not popular in the US, but instead why are dessert pies LESS popular in Europe. And the answer, to put it simply, is sugar.\n\nAs it turns out, throughout the 1700s and into the 1800s sweet and savory pies were neck and neck in terms of popularity on this side of the pond. Sweet pies in the US exploded in popularity, however, during the early/mid 19th century when the establishment of a mainland US sugar refining industry meant the average American could easily and cheaply get their hands on as much sugar as they wanted while their European counterparts were still paying hefty import sums. This easy access to sugar led to an explosion not just in pie making, but also in the creation of jellies, jams, etc.\n\nAnd the rest, as they say, is history. Hopefully this helped answer your question. If not, let me know and I'll do my best to elaborate more.\n\nReferences:\n\nGross, Rachel E. “How Did Pie Evolve From a Medieval Crow-Meat Casserole Into America's Favorite Dessert?” Slate Magazine. Slate, March 13, 2015. \n\nPollan, Michael. The Botany of Desire a Plants Eye View of the World. New York: Random House, 2014.",
"It did transfer over. The difference is that U.S. and Canadian cuisine changed in ways that European cuisine didn't, so that savory meat pies took a back seat. Though, of course, they have never gone away completely. Chicken pot pie, and shepherd's pie/cottage pie are found quite commonly in restaurants throughout both countries, and frozen versions can be found in just about any grocery store you walk into.\n\nThis was imported from England, the Netherlands, and elsewhere right from the beginning of the settlement of the North American colonies. But first, some clarification. As Keith Stavely and Kathleen Fitzgerald describe in their book *America's Founding Food: The Story of New England Cooking*, food preparation in the 17th, 18th, and most of the 19th Century was focused on stretching scarce culinary resources as far as they could go. There were no refrigerators, or freezers, and it was much more important then to use every resource you could. As such, pies were a good way to make something better out of ingredients on their own that weren't so great. The cook could, and usually would, use lard instead of butter. The crust could be a mix of wheat flour and other flours, like rye, whatever was available. And the filling was often a mix between both fruit and meat. While \"mincemeat\" today usually refers to minced fruits, in the early years of colonial America and after, it could just as readily [refer to actual meat derived from an animal, shredded or chopped](_URL_8_) and sometimes mixed together with fruit.\n\nAnd the \"meat\" her wasn't always the good stuff. *Umbles* (animal innards) were often used, giving rise to the dish, and phrase, \"humble pie\". Calf foot, cow's tongue, kidney, heart, suet, and other animal bits that weren't always very tasty by themselves, were used as the \"meat\" in a \"meat pie\", and minced together with fruit, they could be made more tolerable.\n\nThis type of pie was an American tradition going right to the beginning of European settlement in North America. As Sarah Josepha Buell Hale would write in the early American cookbook [*Good Housekeeper*](_URL_10_), published in Boston in 1839:\n\n > \"The custom of eating mince pies at Christmas, like that of plum puddings, was too firmly rooted for the 'Pilgrim fathers' to abolish; so it would be vain for me to attempt it. At Thanksgiving too, they are considered indispensable.\"\n\nHale then gives several recipes for such pies, though she complains that they are \"expensive\" and \"unhealthy\". Her recipe for \"Rich Mince Meat\" includes neat's [i.e., calf's] tongue, \"beef suet from sirloin,\" along with raisins and currants. Her recipe for \"Plain Mince Pies\" includes \"lean boiled beef\", chopped suet, apples, raisins, and currants. This is followed by a recipe for \"Chicken Pie\" which includes the de-boned and de-skinned chicken meat, along with \"the livers, gizzards, and hearts well seasoned\" with gravy and the yolks of five hard-boiled eggs.\n\nGoing back a bit further, the first American-original cookbook, [*American Cookery*](_URL_13_) by Amelia Simmons, published in Boston in 1796, includes recipes for \"beef-flake pie\", \"lamb pie\", \"stew pie\", \"sea pie\", \"chicken pie\", [calf's] \"foot pie\", \"tongue pie\", and \"minced pie of beef\". Some of these are straight up savory pies, while some include the addition of fruits.\n\nSimilar recipes would be found in other early American cookbooks. Eliza Leslie's [*Seventy-five Receipts for Pastry, Cakes, and Sweetmeats*](_URL_17_) first published before 1830 contains her Philadelphia recipes for \"oyster pie\" and \"beef-steak pie\". Mary Randolph's [*Virginia Housewife*](_URL_5_) published in 1838 contains recipes for a pie of \"oysters and sweetbreads\", and a \"sea pie\" that uses \"slices of boiled pork or salt beef\".\n\nBy the mid-19th Century, early restaurant culture had sprung up in New York catering to dockworkers, factory workers, and other urbanites, and [surviving despcriptions of the fare offered](_URL_15_) includes the regular inclusion of meat pies. Most often on offer were mincemeat pies, as well as oyster pies, as descriped in *Urban Appetites: Food and Culture in Nineteenth-Century New York* by Cindy R. Loebel. (19th Century New Yorkers loved oysters.)\n\nThis savory pie-eating was also exported to Canada after the Revolutionary War (if not before, by the French). The earliest Ontario cookbook, [*The Frugal Housewife's Manual*](_URL_11_), published in 1840, contains a recipe for \"mince pies\":\n\n > \"Take two pounds of beef after it is chopped, one pound of sugar, and three pounds of chopped apples, one pound of stoned raisins, half a pound of currants, a glass of brandy, nutmeg, allspice, and cinnamon; a little of each is good, but the most of nutmeg is best: moisten with cider, or water with a little vinegar in it.\"\n\nThe invaluable early Canadian history book [*History of the Settlement of Upper Canada*](_URL_19_) by William Canniff, published in 1869, makes the interesting observation:\n\n > \"Another dish which seems to have been derived from the Dutch, was *Pot Pie*, which was always, and is even yet in many places, made to feed the hands at 'bees' and 'raisings', and was generally made to grace the board on a wedding occasion.\"\n\nIt seems that the \"pot pie\" variation was an innovation--at least in America--of the New York and New Jersey Dutch community. The earliest credited use of the phrase *pot pie* is [in New York author James Fenimore Cooper's *The Pioneers*](_URL_6_), first published in 1823:\n\n > \"The snow birds are flying round your own door, where you may feed them with crumbs, and shoot enough for a pot-pye, any day.\"\n\nSavory meat pie were still a staple of the American diet into the late 19th Century. The widely read women's magazine, *Godey's Lady's Book*, frequently included recipes for meat pies. Among them include an 1879 [recipe](_URL_9_) for oyster pie, 1873 [recipes](_URL_3_) for steak pie and \"rump steak and kidney pie\", and 1878 [recipes](_URL_0_) for \"English pork pie\", and a \"meat pie\" containing rump steak, \"game\", and bacon.\n\nMoving forward, savory meat pies were still found quite regularly through the early 20th Century. As the New York Public Library's online collection of historic American restaurant menus shows, it wasn't uncommon to find mince pie ([1](_URL_14_), [2](_URL_16_), [3](_URL_2_)), [chicken and ham pie](_URL_21_), and [chicken and veal pie](_URL_18_) among others. And their collection mostly consists of the fancier New York restaurants from the 19th and 20th Centuries, like Delmonico's and other upscale restaurants across the country. Assuredly, many of the more working-class restaurants would have had chicken pies, and cottage pies, and the like in this period.\n\nSo, what changed. As explained in [this earlier answer](_URL_15_), by 1870, New Yorkers had several ethnic eating options to choose from beyond traditional English or American cuisine. These included German food, French food, and the beginning of the craze for Italian cuisine, and Jewish and Eastern European cuisine. These same communities had all, to varying degrees, been established in most other major urban centers in the United States by the turn of the century. Certainly, it would have taken longer for them to be established in the still sizable rural communities, and eating out was nowhere near as common in 1900 as it would be a century later. Nevertheless, new dishes began to overtake some of the traditional American ones: German and Polish sausages along with the American innovation the *hot dog*; the German minced steak known as the *hamburger* that Americans added a bun to; but perhaps the most direct threat to the prominence of the savory pie was the importance of French *haute* cuisine in that period. Supper clubs across the country prided themselves on their French fare, as the New York Public Library's collection makes clear. It was at this time, in the early 20th Century, where kitchenware manufacturers and cookbook publishers began to push the idea of the [*casserole*](_URL_12_).\n\nBy then, with food preservation not such an overwhelming concern, housewives were no longer burderened with stretching the innards of farm animals as far as they would go. Mincemeat could be replaced with the better cuts of meat, and a casserole allowed for a tasty dish that didn't require all the fuss of a crust. As this [1909 syndicated newspaper article](_URL_1_) shows, a lot of casserole recipes were very much French-ified substitutes for the older English-style meat pies: kidney casserole, oyster casserole, lamb and peas, liver and chestnuts, ham and egg, beefsteak, and others. Many such articles would appear around this time ([1](_URL_20_), [2](_URL_7_), [3](_URL_4_), for example). \n\n(*cont'd...*)"
]
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"https://www.etymonline.com/word/mince#etymonline_v_44773",
"https://books.google.com/books?id=8UckAQAAMAAJ&pg=PA178",
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"https://chroniclingamerica.loc.gov/lccn/sn85066387/1907-09-08/ed-1/seq-14/",
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"https://books.google.com/books?id=XX4EAAAAYAAJ&pg=PA25",
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|
9yl8h3
|
how does country get richer through protectionism?
|
How this process work? All the 1st world countries were using protectionism at the beginning and only later started to allow free market from what I see. Would it be a disaster for economy if some country let's say from former Eastern Bloc started to use protectionism and why?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9yl8h3/eli5how_does_country_get_richer_through/
|
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"So the idea is that protectionism keeps profits inside your own country. I buy a car from Ford for $20,000, they spent $15,000 to make it, so they earn 5,000 in profit, and because they're an American company, that profit stays in America. I buy a car from Volkswagen for $20,000, they spent 15 to make it, so they earn 5,000 in profit, and that profit goes to Germany, because they're a German company. That sucks for America and is great for Germany.\n\nProtectionism could prevent this by putting tariffs on VW cars. VW cars would be more expensive, therefore I'd naturally buy a Ford instead, keeping the profits inside the US. This helps grow American companies too. \n\nLet's pretend Ford was an upstart company that just started making cars. For the first few years their cars will be shoddy and more expensive, because the company doesn't have experience and they need to pay off all the debt they acquired starting the company in the first place. Well no one's gonna buy these shoddy expensive cars when there's cheaper high-quality foreign cars they could buy. But if the government slaps a tariff on foreign cars, then American consumers *have* to buy the shoddy more expensive cars. This grows the American company into a mature company that can produce cheap and high-quality cars just like Germany. Then we can remove the tariff and have a free market again.\n\nNow, all of this is the *ideal* scenario for protectionism. Sometimes it works like this but sometimes it doesn't and actually makes everything worse.\n\nThe first big problem with protectionism is *retaliation*. Go back to our previous example about the auto tariff. Germany's not just gonna lie down and take it. They're gonna slap a tariff on *our* products in retaliation. They'll put a tariff on American avocados from California. Oh no! Now most of the avocado companies are out of a business. They were an export-oriented business. So we may have done a favor for the American auto business, but we've done a disservice to the American avocado business. This tit-for-tat can theoretically go on indefinitely, to the common ruin of all. You won't import anything (good), but you won't be able to export anything either (very bad).\n\nThe second problem is that any sort of cap on the free market like a tariff is essentially a brake on economic efficiency. You're intentionally hobbling yourself. If you put a tariff on foreign cars to force Americans to buy more expensive American cars, well those Americans are that much poorer now. They spent a few extra thousand on a more expensive car, and they now don't have that money to spend on other stuff. This is a deadweight loss to the consumer. Overall and in the long run, these losses *can* be canceled out by the boons protectionism provides to domestic industry which may trickle down to all as high-wage factory jobs or investor dividends or whatever, but in the short run it hurts.\n\nSo you ask, would it be a disaster if some country from the former Eastern Bloc started to use protectionism. The answer, unsatisfying as it is, is that it depends. For a country like Russia, it would probably be a disaster. Russia is already highly industrialized and would benefit by getting their factories churning again and producing goods for export. Getting into a tariff tit-for-tat for them would be a disaster as they're already a heavily import-reliant economy. Romania was not quite as industrialized, so maybe they could benefit from some protectionism helping them grow their industrial base before they transition to a free-trade economy. ",
"If you're a relatively poor country, you like free trade, because you can use the cheapness of everything in your country as a competitive advantage.\n\nIf you're a developed country, free trade turns out to be a race to the bottom that destroys your middle class. Because if your wages are above what it would cost to get the work done in poor countries, you lose jobs until people in your country are poor too.\n\nAnd then your politicians tell people everything is just peachy, which really pisses them off but there's nothing they can do about it, until finally somebody with orange hair rises to the top by promising to put your country first.\n\nWhich involves building economic tariff walls, and literal brick-and-mortar walls, both of which put you in direct conflict with the greatest wall-building civilization the world has ever known. Will these policies help? I think the tariffs might (literal walls, I'm pretty sure, became obsolete when we researched the Rifling tech a couple hundred turns ago). But everyone who seems to know more than I do about these issues says it will just make things worse. I agree tariffs always make the world as a whole poorer by throwing a bit of extra sand in the gears of the economic machine. But that's a worthwhile trade-off if it means you can get your middle class back, which is a very important part of stabilizing your society.\n"
]
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[] |
[] |
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[],
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|
24nc0m
|
How can we detect Anti-matter stars if they exist?
|
Should a sun made of anti-matter emit a spectrum similar to our sun or will it be different?
|
askscience
|
http://www.reddit.com/r/askscience/comments/24nc0m/how_can_we_detect_antimatter_stars_if_they_exist/
|
{
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"If there are pockets of the observable universe where antimatter is common, then those pockets will have borders. At the borders, a primarily matter region will be interacting with a primarily antimatter region, meaning they will be annihilating each other, which we could detect as very energetic gamma rays."
]
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|
[] |
[] |
[
[]
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szdtr
|
what the current state of the marvel comics universe is
|
I've always loved comics, but I grew up very far from any respectable comics shop. I recently moved across the country for a job and ended up living right next to two awesome comics shops, so now I'm in heaven. My move coincided with DC's new 52, so it was really easy for me to pick up some new titles to read from that. I also read a few things from Dark Horse (Hellboy, BPRD, some of their licensed comics like the Mass Effect ones) and some of DC's new Vertigo titles (only like 2 issues in each at the most right now). I also picked up Saga. Brian K Vaughn is awesome.
I read these comics because a lot of the series are new, or told in short story format (BPRD) and therefore easy to pick up. I pirate comics if it's necessary for me to get up to speed with a book I'm subscribing to, but I don't enjoy the feeling.
Therefore, when I look at the big Marvel titles (honestly, how many different ways can you combine the letter X with other words?) and see the hughe number of seemingly interrelated titles, and ridiculously high numbers they're running at, and how many different X-men titles they're publishing at the same time, I get totally baffled and overwhelmed. Right now, the only Marvel book I'm reading is the new Matt Fraction Defenders, because they're only on issue 5 (and pretty damn awesome, too).
So: what's the Marvel universe like? Are there parallel worlds? What are the flagship titles? Which X-men books are spinoffs of which other ones? Is there anything going on to promote the upcoming Avengers movie that I should know about? What are the major story arcs and crossover plots going on right now and what should I read in order to understand them? If I were going to go pirate 50 issues tonight, which ones should I read to get up to speed on the current good titles? I dodn't really give a shit about characters' complicated back stories, or how the multiverse is exactly organized, or any of that shit. If you were introducing your 5-year-old kid to Marvel comics, and they hated jumping in the middle of a story without knowing what was going on, what would you tell them?
**EDIT:** I think people have been coming in here and downvoting all the comments? I've noticed a couple passes of all or most of the comments getting hit by -1, anyway. Jesus, guys, if you don't like the suggestions, make some of your own.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/szdtr/eli5_what_the_current_state_of_the_marvel_comics/
|
{
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|
26msmk
|
To what extent is the modern notoriety and recognition of Caesar, Antony, Cleopatra, Brutus, etc. the result of Shakespeare?
|
If it weren't for Shakespeare, would Julius Caesar, to say nothing of Mark Antony, be such a universally recognized name?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/26msmk/to_what_extent_is_the_modern_notoriety_and/
|
{
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"I can only speak about notoriety and recognition in the anglophone world.\n\nCaesar, Antony, Brutus, and Cleopatra would definitely still be remembered without Shakespeare's plays. Having one of the most famous writers in history make your life into a narrative piece of theater is certainly helpful when it comes to staying in the public conscious, but these particular historic figures would probably have needed no such help. Especially Caesar himself.\n\nThese stories were already popular in England in the 1660s-70s when Shakespeare was young. Stories about the Roman Republic/Empire were considered essential parts of a good education. Latin was taught to students and portions of the works of Plutarch, Ovid, and Plautus were used as practice texts.\n\n[Plutarch's *Lives*](_URL_1_) was first translated into English by Sir Thomas North in 1597. It was apparently a great success, as orders for a second printing were recorded later that same year. This translation was almost certainly used by Shakespeare as the basis for his play as I discussed in [a previous answer](_URL_0_).\n\nIn addition to being yet another popularizing force behind the life of Julius Caesar & company, Shakespeare also became responsible for a number of misconceptions about the story: He compresses the events of several years into 5 days. He makes the Capitol the venue of Caesar's death rather than the Theatrum Pompeium. Shakespeare makes the Triumvirs meet in Rome instead of near Bononia. The period between Caesar's victory and Antony/Octavius regaining control is a span of 3 years, not one week. Caesar's assassination and the dueling speeches of Antony and Brutus happened months apart according to Plutarch while Shakespeare places all three events on one gigantically important day: The Ides of March. Shakespeare's final battle happens on the fifth day of the play, where Plutarch sets it months after the assassination.\n\nTo sum up, the public memories of Julius Caesar and Mark Antony were not in danger of fading when Shakespeare wrote his play. Indeed, he may have been responsible for as much confusion as awareness. On the other hand, Shakespeare made the character of Brutus much more interesting, conflicted, and three-dimensional than the one we read about in Plutarch. So I suppose it's safe to say that Shakespeare probably shaped the way we now view Brutus more than any other writer."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/AskHistorians/comments/21h57t/how_much_of_shakespeares_julius_caesar_is/cgd0ci0?context=3",
"http://books.google.com/books?id=1LcUAAAAYAAJ&printsec=frontcover&dq=Plutarch's+lives&hl=en&sa=X&ei=AvmEU53_L5SjqAaj2IDoCA&ved=0CC4Q6wEwAA#v=onepage&q=Plutarch's%20lives&f=false"
]
] |
|
3g24y8
|
why do radio stations change by region?? and how come xm is the same across america/the world?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3g24y8/eli5_why_do_radio_stations_change_by_region_and/
|
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"Radio stations have an antenna and they broadcast their signal out. But the Earth is round, so most of the Earth isn't within reach of the antenna (there's a planet in the way of the signal). So you only receive the signal of radio stations near you. \n\nIt's the same reason why broadcast TV stations are local but cable and satellite TV stations are national. The broadcast only covers a short area, but by sending the signal along wires or between satellites, you can carry it all over the world.",
"FM radio broadcast antennas have a maximum range of about 100 miles, give or take. If you're more than 100 miles away from one station, you're not going to be able to pick it up with an antenna.\n\nXM is satellite radio. Your car is picking up signals from satellites orbiting the Earth.\n",
"Radio frequencies have a limited line of sight range and are broadcast from a fixed point on the ground. Various things like building, hills, mountains among other interference sources limit the range.\n\nXM is a satellite system that transmit their signal from space to the ground so a single satellite can reach a much larger area as there is little to no line of sight interference",
"XM is satellite based so anywhere on Earth that has a line of site to the satellite can receive the XM signal.\n\nNormal radio stations (now called terrestrial) broadcast from tall towers using a massive amount of power. The height and the power allow the station to be heard over a wide area but like all electromagnetic waves, the radio signal loses power the farther it travels. Eventually it loses so much power, radio receivers can't decode it any more. \n\nSince running a radio station is a very lucrative business, stations have popped up to cover all the areas of the US that have any substantial population."
]
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|
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38ibez
|
why is there such a disconnect between science and the government?
|
For example why do LSD and psilocybin remain classified as ‘schedule I’ (high potential for abuse, no accepted medical usage, and lack of safety even when used under medical supervision), or why is saturated fat and cholesterol still considered bad and to be avoided at all cost? Shouldn't the government follow science? Why does it take so long to catch up?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/38ibez/eli5_why_is_there_such_a_disconnect_between/
|
{
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"Because there is a disconnect between people and science.\n\nThe government will only change things that benefit them, or that there is enough public demand for that changing it would increase their chances of continued election.\n\nIf the majority of voters either don't know or don't care about something, the government is under no obligation to change it."
]
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|
[] |
[] |
[
[]
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|
cxwafw
|
Floating Feature: STEM the Tide of Ignorance by Sharing the History of Science and Technology
|
AskHistorians
|
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"So I get that the Soviet propaganda poster is sort of a joke, but there is an interesting Soviet tie-in to the modern study of the history of science. \n\nOne of the most impactful papers given in the 20th century study of the history of science was that given by Boris Hessen, a Soviet physicist, at the Second International Congress of the History of Science, held in London in 1931. It was a Marxist interpretation of the work of Isaac Newton, situating it within the context of 17th century England, which is to say, an economic, political, and religious context that any good Stalinist would label as \"bourgeoise.\" This looking at the context of Newton, and showing the bridge between it and his work, had an immense influence on Western scholars, who ended up following this strain of \"external\" factors in the history of science to some very successful ends.\n\nBut why did Hessen give this paper? The story is quite interesting. He had been involved, in the 1920s and 1930s, in trying to defend Einstein's work, as well as the quantum physics that came after it, from accusations of being \"bourgeois.\" In the high days of Stalin's purges, such attacks — leveled by philosophers who hated relativity theory and the ways in which it seemed to counteract the dialectical materialism of Marx, Engels, and Lenin — could be deadly for a field (Cf. Lysenkoism). Hessen was one of several brave Soviet physicists who attempted to make attempts to show that whatever the context of the creation of Einstein's theories (and that context was, indeed, bourgeois and \"cosmopolitan\" by Soviet standards), the work itself stood up. \n\nHow to make that defense? There were many different ways to attempt this, such as Vladimir Fok's rebranding of General Relativity as merely a \"theory of gravity\" (and throwing out all philosophical conundrums). Hessen's was through history: the philosophers held up Newton's laws as the ultimate expression of materialist truth, and so Hessen would show that Newton was certainly as bourgeois as Einstein et al. If he could do that, he hoped, the philosophers (or party functionaries) would perhaps accept that indeed the context could be separated from the science. \n\nAs historian of Soviet science Loren Graham writes, \"the unwritten final line\" of Hessen's paper \"was that when Einstein wrote on religion or philosophy he also merely expressed his social context and therefore these views should not be held against physics\"—what you can do to Einstein, I can do to Newton, so let's leave science to the scientists and history to the historians. \n\nIt's not clear that Hessen's paper was successful within his Soviet context; ultimately the \"rehabilitation\" of modern physics came when it became valuable for war, and that was just around the corner. Hessen himself was arrested by the NKVD in the late 1930s; there are conflicting accounts of his death (in one he was executed by firing squad, in another he simply died in prison). He was official rehabilitated by Khrushchev in 1956. \n\nOutside of the USSR, \"the Hessen thesis\" became the spark of an entirely new line of historical inquiry — looking at how the social, cultural, economic, and religious context of scientific development influenced the context of the theories themselves — and much of this work, ironically, went to very different ends than Hessen's. Instead of being about the separability of scientific content and its context, it rather became about the inseparability. It marked, ultimately, a move away from the hagiographical and \"internalist\" approaches to the history of science — looking at it less as a list of discoveries or evolution of equations, and more as a realm of human society, just as fraught and complicated as any other.\n\nFor more, see: Loren R. Graham, \"The Socio-Political Roots of Boris Hessen: Soviet Marxism and the History of Science,\" _Social Studies of Science_ 15, no. 4 (November 1985), 705-722, and Loren R. Graham, “Soviet attitudes toward the social and historical study of science,” in _Science in Russia and the Soviet Union: A Short History_ (New York: Cambridge University Press, 1993), 137-155.",
"I am here to talk about **MEDIEVAL BATTLE MECHA.**\n\n*Edited from an [older answer](_URL_0_)*\n\nOkay, the European Middle Ages weren't about to produce an Artoo Detoo, a Roomba, or even a Unimate. (Although they did produce plenty of *robota* in the original Czech meaning.) But people did imagine, sketch, and eventually construct what we call *automata.*\n\nWe might define \"automaton/automata\" (an anachronistic word as far as the Middle Ages are concerned) as a constructed object that is self-moving or even self-powered, in set patterns under set conditions. A perpetual wine fountain at a feast is shaped like a naked woman with the wine flowing out exactly where you think it does. A water clock at a 10th century monastery reminds the nuns when to pray.\n\nA \"Wheel of Fortune\" painting shows Fortuna hand-cranking a smaller, easier gear-wheel that turns the larger and more treacherous *rota fortunae* that makes kings rise--and fall. Metal lions roar; copper knights that raise and lower their swords.\n\nThe wine fountain...founts wine, and the water clock keeps time. So the copper knights raises the question: **Were medieval robots used in war?**\n\nFor most of the Middle Ages, Latin Europe's ability to dream about automata and what they could do *radically* outpaced any ability to construct them. The attraction of dreaming about automata was the lure of the exotic. Machines represented the ancient, the foreign, the magical. They were often discussed in literature (narrative and academic) as if they were magic. Their builders were described as sorcerers or quasi-sorcerers. \n\nSo next time you think your software dev job makes you cool, remember: medieval engineers were believed to delve into astral magic and necromancy.\n\nAutomata were especially popular in the vernacular (non-Latin) romance literature that grew out of 12th century courts. The primary audience for this genre wasn't scholars or clerics. It was \"those who fight\": ladies and lords.\n\nAnd here, in the romances, we see authors pondering how automata might be weaponized. Unsurprisingly, given the association of robots with the ancient and exotic, one of the most striking occurrences lies in the mid-12C *Roman de Eneas*, whose title you might recognize as a French retelling of the Aeneid. \n\nIn this romance, Camille's tomb is guarded by a golden archer--but in a very clever way. The tomb itself is perpetually lit...so long as no one enters. If the threshold is crossed, a trip wire of sorts (it is not clear in the text) causes the archer's bow to release and shoot an arrow across the tomb. The arrow pierces a golden bird which pulls a chain that snuffs out the light. The intruder is now trapped in eternal darkness.\n\nSlightly more mobile possibilities are provided in the Arthurian tradition. In the 13C fanfiction ending to the unfinished *Perceval* of \"Chretien de Troyes,\" a castle is cursed by a demon trapped inside a copper bull that magically melts away when the demon is exorcised. The castle is guarded, however, by copper men who are less magical and more mechanical. They hold hammers that drop heavily and life-endingly on passers-by. And in various *Lancelot* traditions, bridges, buildings, and even rooms are guarded by copper knights.\n\nThe pattern you'll notice is that the automata are *defensive*, of course, but even more so that they guard thresholds--bridges being the obvious one, but also between light and darkness, life and death, curse and salvation. A key point E.R. Truitt makes in her book *Medieval Robots* is about the *meaning* of automata in Latin medieval culture: the unease over [whether/to what extent machines can be alive](_URL_1_).\n\nSo medieval writers, and the nobles (including some monks and nuns!) who enjoyed their books, had the idea of weaponized automata, but channeled into certain paths that recapitulated or played into contemporary fears over the natural versus the supernatural and the boundaries of life.\n\nBut when we see actual automata planned and constructed in increasing numbers in the late Middle Ages, in the west, their primary function is court pageantry and show! They are permanent fixtures in castles or in gardens, or temporary constructions for a lavish feast, designed to impress and demonstrate conspicuous power. \n\nWhat happened? Why do the dukes of Burgundy use automata to dump flour on loyal courtiers instead of molten lead on invaders? Why don't armies mechanize their siege engines?\n\nThe most important clue is actually provided by a shift in how literary sources talk about automata, and especially their makers. By the 14th-15th century, machines are much less frequently a result of sorcery or magic or arcane permutations of the liberal arts. Instead, they are described as crafts and built by master artisans. It took significant collaboration of different trades to build the mecha that would have been on display at courts. \n\nThese were not cheap in terms of material *or* manpower--indeed, that was a major reason they were such powerful displays of obscene better-than-you wealth; I have so much I can *waste it on this triviality*. These are not practical things to construct.\n\nSecond, account books show that mecha were also highly impractical to *maintain*. Among permanently-installed mecha in gardens, something or other always needed repair. And the *entrements* displayed at feasts were temporary by design: can't have a repeat performance; that wouldn't impress enough. These were not hardy machines to hold up to war, or rather, to travel for war.\n\nThird, the elaborate methods of powering many mecha would not have worked on the road, or with various materials used in warfare. You can have a perpetual wine fountain, but probably not a perpetual boiling oil fountain. Pools of water and the deliberate constructions of placement involved in one element working another depended on staying in a very particular place; uneven terrain or jostling could upset them.\n\nThe Latin Middle Ages certainly experimented with and developed mechanical weapons, most famously the crossbow. But these required human initiative.\n\nSo overall, in the Middle Ages you wouldn't see Pacific Rim-style mecha swarming over the European landscape. Automata were larger than life in conception and imagination, but generally life-like in size. However, Europeans could and did envision robots doing violence to humans--and envision robot engineers meeting with angels, traveling through the underworld, and summoning demons to Earth.",
"**Part 1**\n\n\nI'm going to talk about a development in the history of science and technology, but not just a development in a particular field, but a cross-cutting one. In the 16th and 17th centuries, in the north-western corner of Europe something amazing happened for the first time in history, as far as we know, the first victories in the war against one of the Four Horsemen of the Apocalypse: famine. \n\nThe last peacetime famine in the Netherlands was in the 1590s, in England in the 1620s, in lowland Scotland in the 1690s. There were still periods of widespread shortages and hunger, and individual tragedies, and, in the Netherlands, famine during wartimes (eg the 1690s), but it was still a sign of a seachange in the lives of the poor. Oddly enough this amazing change gets virtually no attention in general histories. When I was at high school in NZ, in seventh form (the last year of high school) we did a whole section on English history 1558 to 1666, including social history and opinions of marriage, but this incredible jump in well-being was never mentioned, not in the external exams nor by our teacher, though he did find time to go into the histography of Charles I. The end of famine in England and the Netherlands at least have made it into Wikipedia but I have been searching for the dates of the last Welsh famine and I can't find it. \n\n\nWhy not, when the history of vaccination is commonly known? Perhaps because the disappearance of peacetime famines happened first for the wealthiest and most literate, while they still were exposed to the risk of diseases like small pox. Perhaps because it was a gradual thing, with no clear set of innovations like we can trace with innoculation.\n\nSo why did famines cease? Well to avoid a famine, two things have to happen, enough food has to be produced and it has to be distributed to the people who need it. Both factors were at play in the Netherlands and England. However the influence of both is also debated, in part because we have limited data on the great masses of people in the 16th and 17th centuries even in the Netherlands and England, and the *end of famine* is a story of the poorest. So I'm going to discuss what we know about both, and about how the historiography of this has been changing. \n\n\n**Production** \n\nThe famous change in English agriculture of this period is the \"enclosures\": the practice of consolidating small scattered land holdings and commonly owned lands (known as \"open field farming\") into consolidated, privately-owned farms. Enclosure was widespread in England during the 16th to 18th centuries. Part of the reason for the fame of the English enclosures is that Karl Marx argued that enclosures were a key part of England transforming from feudualism into capitalism, turning farmers from producing for subsidence to producing commodities for markets. \n\n\nTraditionally, economic historians regarded open field farming as hidebound, conservative and prone to overgrazing: believing that the enclosures enabled the British agricultural revolution between the 1650s and 1800. However, you will note that this traditional dating has the agricultural revolution starting after the 1620s, the date of the last English famine. \n\n\nFrom the 1970s, economic historians began to challenge the view of the importance of enclosures. There's now evidence that open field farming was tightly tied to market production, that open field farming was more efficient than previously thought, and, overall, that agricultural output in England was rising from medieval times. \n\n\nIn terms of market production, there's evidence from the early sixteenth century (so 1500s) of market orientation. The probates of the wills of small-scale farmers show that the wills' executors (typically also farmers) valued holdings of unsold grain were valued at similar prices to that of grain sold in wholesale markets, including changing in similar ways, which is hard to explain if the valuers were disconnected to markets. \n\n\n In terms of open field farming, Deidre (then Donald) McCloskey argued in the 1970s that open field farming was efficient because it allowed diversification: land conditions can vary significantly even over small areas (classically, when it's wet, upland areas are not as water-logged, when it's dry, upland areas can be too dry for optimal growing). There is strong evidence that medieval farmers also had systems for protecting commons from over-use, which ties into Elinor Ostrom's (2009 winner of the Nobel Memorial Prize in Economics) work in how [commons can be successfully locally](_URL_0_) managed. And this sort of research is leading the economics profession to change its terminology from Hardlin's [Tragedy of the Commons](_URL_1_) to the Tragedy of Open Access. That's a pretty radical change in how the open field system is viewed. \n\nOn top of this improved view of the efficiency of open fields farming in static terms, there's also evidence of agricultural innovation. During medieval times for example there was a shift from two field crop rotation to three, or even four field rotation systems, drastically reducing the amount of time land would spend lying fallow. English agriculture during this period also saw the substitution of horses for oxen, and changes in land use between cropping and pasture in response to prices. \n\n\nThis is not to say that there were no efficiency gains from enclosure. Robert C. Allen in the 1980s and 1990s presented evidence that enclosed fields gains in crop efficiency, relative to open fields, averaged about 10 to 15 percent. Obviously these gains are not to be sneered at, but they are in the context of an estimated doubling of agricultural yields between the middle ages and the nineteenth century. (Allen even goes so far to argue that enclosures was motivated not by productivity gains but by giving landlords the opportunity to raise rents - a reallocation of incomes rather than an increase in the total. However Deirdre McCloskey criticises him on this on several grounds, perhaps the strongest is that Allen's view implies a surprising willingness of the landlords of open fields to give their tenants good deals.) \n\n\nSo not only did the 15th to 17th centuries see a big improvement in agricultural technologies, the history of this time has helped change the direction of economic science.\n\n\nBut these agricultural improvements weren't confined to England and the Dutch, northern France also shared in them (including what would become the southern part of Belgium). But famines there continued. Which leads me to my next section.",
"**Fresnel's White Spot**\n\nCredit for the best researched account of this story I've read goes to [John Worrall](_URL_3_).\n\nImagine if you will the French Academy in the early 1800s. A pre-eminent institution for science, dominated by gentleman aristocrat scientists, the elite of the elite. It included several historical heavyweights with mathematical and physical entities named after them, like [Laplace](_URL_1_), [Poisson](_URL_4_), [Biot](_URL_0_) and [Gay-Lussac](_URL_2_). \n\nThe Academy members were mostly devotees of the orthodox Newtonian view of light as particles (the theory you probably learned in high school), and none of them foolish enough to even consider the discredited view that light might be waves in a medium. There were, as is normal in science, as few niggling details to work out with the (by and large very successful and accurate) Newtonian theory. So, in 1817, the Academy held a prize competition for contributions to understanding the diffraction of light, expecting submissions based solid Newtonian reasoning.\n\nEnter: Augustin-Jean Fresnel, only 30 years old, nobody-son-of-an-architect, just returned from serving on the front lines as a military engineer. He had the gall to submit an entry based on his own new derivation of a wave-based theory. To really rub in just how ludicrous this was, when the prize commission was deliberating, commission-member and undeniable mathematical genius Siméon Denis Poisson derived a patently absurd consequence of Fresnel's theory. Fresnel's math implied, Poisson showed, that if you shine a light through a hole, and put a disc in front of it at just the right size, just the right distance, the circular shadow of the disc would have a bright spot in the middle, as though it had a hole in it and the light was shining through. Preposterous! \n\nFresnel did have one supporter on the commission though: François Arago who, just to be sure, made a tiny 2mm disc and held it at just the right distance from a point source of light and.... BEHOLD! A white spot! A completely novel observation, previously thought absurd, only predicted by an attempt to *disprove* a theory! \n\nWithin a few years Fresnel's theory had spread like wildfire. Scientists everywhere converted from thinking of light as particles to light as waves. Of course, today we know that they were wrong too and light is some super-imposition of both that nobody really understands. Of course, also, the history isn't as clean and simple as this few-paragraph story suggests: there weren't really other viable contenders for the prize, many scientists held to the particle view their whole lives, etc., see Worrall's linked essay above for details. Still, running an experiment to prove someone wrong, and instead revolutionising the entire foundation of physics, that's some pretty cool history of science.",
"Time for a story on the **Genevan Watchmakers**\n\nWhile anyone familiar with the history of timekeeping and watches will have read David Landes’ *Revolution in Time*, today we’re going to flip Landes on his head and look at ‘time in revolution’. In 1717, as a young child the *citoyen de Genéve*, Jean-Jacques Rousseau, moved with his father and brother into a flat at 15 Rue de Coutance in Geneva’s artisan neighborhood of St. Gervais following the death of his mother and subsequent sale of their house. St. Gervais was, in the words of Patrick O’Mara, “the focal point of the democratic agitation in the city-state” in the decades to come and the Rousseau’s new landlord, François Terroux, and fellow tenant, Jean-François Badollet, had been both labelled by the authorities as passionate and violent revolutionaries. In short, “The house in which Rousseau [would spent] five formative years of his life was one of the principle foyers of democratic ideas and agitation in Geneva.”\n\nJean Jacques’ father, Isaac, along with Terroux, Badollet, and many more in their neighborhood were watchmakers, and by the time the Rousseau’s had moved to St. Gervais their craft was the single largest industry in Geneva. The watchmakers grew to such prominence for two predominant reasons, and the first is simple; beginning in the late 17th century, social interactions, trade, labor, etc. became increasingly tied to time as watches were increasingly more and more reliable thanks to inventions such as Huygen’s balance spring. The second reason for the massive growth of Genevan watchmaking had to do with output. Watchmaking in Geneva, *La Fabrique* as Anthony Babel called it, increasingly became organized under a system called the *etablissage*, whereby master watchmakers increasingly took on the additional role of being a merchant becoming *etablisseurs*. Rejecting the organizational structure of the admittedly weak Genevan watch guild, whereby masters worked with a journeyman and apprentice to produce roughly one watch per month, these merchant watchmakers contracted out the rough production of pins, springs, wheels, and whatnot to those groups of people who had been historically denied entrance into the guild; namely immigrants and their children (*habitants* and *natifs*), women, and peasants in the surrounding land. All these various pieces were then given over to the *cabinotiers*—watchmakers who didn’t have the capital or name recognition to be top dogs themselves and who got their name from the very small ‘cabinet like’ work spaces they had in the higher levels of buildings to get the most sunlight— for the assembly of the movements, cases, etc., and for them to be polished. Etablisseurs would then give the watch some finishing touches and call it a day by signing the movement or dial with their name. How much more efficient was this system, you ask? Well recalling that guild production averaged about one watch a month, Landes cites a contract from 1654 whereby a merchant watchmaker filled an order of twenty-one rough movements, a contract that would have been almost impossible for the guild watchmaker to pull off and remain in business.\n\nSo what does this have to do with revolution? Beginning in 1716, the Small Council—the people with all the political power in Geneva and who all came from same like 15-20 super wealthy aristocratic families— began issuing new taxes on things like legal paper and playing cards and doubling the existing taxes on wine and wheat (for the folks who study ancien France, think of these as Geneva’s gabelle). Now legally speaking, the Small Council didn’t *really* have the authority to do this. They were required to received consent from General Council which was comprised of all citizens and burghers (bourgeois) in the city, roughly 1,200-1,500 people in a city-state of around 20,000. The Small Council justified their actions by citing a 1570 edict that had *”temporarily”* given the Small Council this authority in a time of economic instability. The issue was that that 1570 edict never really spelled out when their authority on taxation ended, so while they were violating the *spirit* of the law they were nonetheless within the letter of it. \n\nThis all came to a head in the fall of 1718, when two anonymous letters were sent to a bunch of well to do merchants in Geneva calling for people to make public representations to the Small Council and demand that they give the power of taxation to the General Council. From December 7th to the 15th, groups of artisans made daily representations and harassed the Small Council over the taxation question. The group leading these movements? You guessed it, the watchmakers of St. Gervais. In fact, they were the only group to act collectively during this week of protest; representatives from other industries addressed the Small Council as either citizen or bourgeois. The *Affaire des Deux Lettres Seditious*, as it was called by the Small Council, effectively ended on December 15th when the SC publicly proclaimed that anyone caught with a copy of either letter would face severe fines and/or have their social rank demoted. I say effectively ended because, while this ended the matter for most people, watchmakers like Terroux and Badollet held out for a few more days. \n\nOne name that does not appear at all in the Small Council’s register, however, is Rousseau. Now does this mean that Isaac wasn’t committed to the cause? Well it seems unlikely since he had participated in a previous, much more violent, protest movement in 1707 and would become politically exiled from Geneva in 1722. In fact, the only watchmakers that appear are those who’s tax bracket would indicate they were those previously mentioned merchant watchmakers, etablisseurs. The reason for this bourgeois led movement (in every sense of the term) has to do with time. Geneva in December of 1718 had about 8 hours of sunlight a day, and those cabinotiers who did a lot of actual watchmaking needed that time to fill the increased number of orders placed in time for Christmas. The etablisseurs, on the other hand, had more time in the day to walk across the city and make those representations. They had far less work than anyone else in the *Fabrique*, and, if they really wanted to, could pass off the responsibility of finishing and signing to a trusted cabinotier. Because they had forgone the guild system which had strict rules related to social class, the threats of demotion wouldn’t affect their bottom line to nearly the same extent that it would other industries still reliant on guild structure.\n\nAnd that, my friends, is how a revolution in time(making) made for the possibility of time(makers) in revolution. \n\nFurther Reading:\n\nPatrick O’Mara, *Jean-Jacques and Geneva: The petty bourgeois milieu of Rousseau’s thought*\n\nPamela Mason, *The Genevan Republican Background to Rousseau’s “Social Contract”*\n\nDavis Landes, *Revolution in Time*\n\nRichard Whatmore, *Against War and Empire: Geneva, Britain, and France in the Eighteenth Century*",
"When I was getting my Bachelor's, I got a job at the University library. They were working on digitizing a bunch of old theses from the 1800s and early 1900s. I was reshelving them all in the deepest depths of the library where no one ever went. Apparently you could get a PhD back then by writing a 10 page report with one hand drawn chart.\n\nOne from the 1870s stood out. It dealt with drinking water and believing that there was something in the water that was making people sick, but he didn't know what it was. He hypothesized it was something too small to see. Which microorganisms humans couldn't see wasn't an uncommon thought then, but it earned him a PhD.\n\nI sat in the stacks and read those papers that no one had read in ages. The authors were long dead, but the papers were in their handwriting. It was fascinating to me. That and the fact that I knew more about science from watching Saturday morning cartoons than those authors with PhDs. The fact that science and the standards have increased so much in such a relatively short time was fascinating.",
"Someone put a lot of work into that title and I want them to know that I am proud of them.",
"Sir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown was a Scotsman, but his questionable legacy is tied more to Canadian history than to his native land. A tinkerer by disposition, as well as a veteran and sportsman with a love of firearms, he spent the 1890s working to perfect a straight-pull bolt-action rifle which would result in the rather infamous instrument that would bear his name, the Ross.\n\nBritain didn't need what he had to offer, but across the Atlantic, Sir Frederick Borden, the Canadian Minister of Militia Frederick Borden was looking to assert a little independence. In light of the Boer War and issues with resupply of the Lee-Enfields, he desired whatever arm Canada carried to be built there, but was unable to garner any interest from British manufacturers so had decided to set out to find something new. \n\nSir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown knew he had an opportunity on his hands and he *dazzled*, although not as much as the rifle itself. Despite the fact that the initial tests were somewhat underwhelming, Sir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown promised that the kinks would be quickly ironed out, and that it was mostly due to the poor quality ammunition supplied for the trial anyways. Not that the trials mattered. Borden had already decided it was the winner, and ensured that the Committee observing was little more than a rubber-stamp, with not professional soldiers, but assured backers Samuel Hughes, Conservative MP and Canadian nationalist, and J.M. Gibson, head of the Dominion Rifle Association. Both target shooters, they appreciated the precision of the rifle, and the idea of the design, despite its obvious, glaring flaws. Even the fact that Sir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown was literally caught sabotaging the Lee-Enfield being compared didn't change things. Despite its current flaws, they believed that with some minor tweaks it would be an excellent rifle they couldn't pass up on.\n\nThe silver bullet for the whole matter was Sir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown's promise that he would use his own money to build the factory! What a deal! How could Borden not have seen it as a sure thing? He was pleased as punch with the entire deal, and Sir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown was given a contract, as well as a 99 year lease at $1 per year for land to build the factory on. The actual military leadership had been given no real say in the process at all, Major-General O’Grady Haly, military commander of the militia, having only been told after it was signed, and the military establishment was quite perturbed, seeing no sense in following a different pattern than the British beside whom, in any major conflict, they would be deployed.\n\nNo matter though! Full speed ahead, eh? In early 1902, the *Rifle, Ross, .303 inch, Mark I* officially entered service with the Canadian Army, or rather, they did on paper, since the factory was only just being built. Although the contract was for 12,000 rifles that year, and 10,000 delivered yearly, there were a number of delays, none of which related to the payments Sir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown received however. The rifles themselves were to be priced at $30 per, which was considerably pricer than British Lee-Enfields cost to make, especially with the added delays. But a little extra cost is worth gaining national pride and self-sufficiency, right?\n\nThe first actual rifles would finally roll out in 1905... and so began the near endless controversy over the creation. Reports quickly came back about receivers exploding, and users coming down with \"bolt-to-the-face-itis' due to inadequate locking. The Mounties, who had been given the first 1,000, were soon exchanging them back for their older but reliable Winchesters. Deliveries quickly slowed down of course as problems were tackled. A quick fix resulted in the Mk II rifle, but as any coder knows, you fix one bug and you now have three. A series of continued attempts to solve the problems in the design resulted in the Mk II\\*, Mk II\\*\\*, Mk II\\*\\*\\*, Mk II\\*\\*\\*\\*, and Mk II\\*\\*\\*\\*\\* bring rolled out one after the other, with any number of differences between the versions. Seeking to avoid embarrassment over the fiasco, the various rifles went through a rebranding as the *Rifle, Ross, .303 inch, Mark II* (Mk II\\*\\*), and the others as 'Short' rifles either Mk I or Mk II. \n\nIn Parliament, scandal erupted over the entire matter, with accusations of bribery and incompetence being thrown back and forth, with the Conservatives even trying to topple the Liberal government over the scandal, although they were stymied in going to far due to their own MP, Sam Hughes, who was the the most dedicated backer in Parliament. Sir Charles Henry Augustus Frederick Lockhart Ross, Ninth Baronet of Balnagown himself was practically immune from criticism, protected by political allies he had made over the decade, and there was little chance of abandonment of the rifle entirely, or even of serious government interference which was blocked by the Small Arms Committee investigating the issues, thanks to its diehard backing member, Sam Hughes, who protected it against all comers. \n\nAnd of course, many Canadian notables were vocal supporters as well, finding a sense of national pride in the idea that Canada would be self-sufficient in defense, compared to the other Commonwealth nations. It certainly helped that *well cared* for rifles in the hands of experts were wowing the world with its accuracy. In 1909 the Ross armed Canadians defeated their British cousins and the SMLE at the Bisley matches which saw forces from the Empire competing with their service rifles, and both cried foul, and took perverse pride, in the British literally changing rules to try and exclude the rifle from service rifle shooting matches. The rifle was proving itself, and in any case, the problems were going to be fixed soon, right? Ross stand on guard for thee!\n\nFinally in 1911, the Mk III rolled off the line, supposed to be a major overhaul which had really fixed all the problems. *Supposed to* being the key word. To be sure, the earlier problems were mostly fixed! It finally used a charger-loaded magazine, better sights, and more importantly, had significantly redesigned the bolt-head to provide strength and durability with seven small locking lugs instead of the single lug of the earlier design. \n\nBut while as a target rifle at the Bisley matches, and pretty parade piece for a peacetime force the Ross might have finally reached serviceability, the outbreak of war, massive expansion of the Canadian military, and the conditions faced in Europe exposed just how flawed a design the Ross continued to be. For starters, the changed had created some rather complicated maintenance requirements which might not matter much in garrison, but were a step short of hell for a poor Canadian boy dealing with fouling and jams in some trench in France. This was only amplified by the fact the Ross couldn't use the same ammunition as the British. Despite both being nominally .303, the Canadian ammunition was lower pressure, and the higher pressure British ammunition would quickly jam the rifle. But most famously was the fact that while the bolt being able to decide it wanted out on its own was solved with the locking lugs, this only was true when assembled *properly*. The fatal flaw of the design was that the bolt head could be put on backwards during fieldstripping, and still be inserted into the rifle by the unsuspecting user, leading to malfunctions and bolt failure. The problem was actually known, but it was assumed *before* the war that troops all know how to put their rifles back together, something which proved to be quite false with the quickly raised and trained force of 1914-'15.",
"George Washington could be called the USA's first developer. He was fond of what was called the Northern Neck of Virginia, an area he helped to survey as a young man, and especially the Potomac River valley. He wanted to use the river for transportation, but the Potomac has two large problems. First, it traverses a number of rocky ledges that block easy passage during low water , including a real big set at Great falls. Second, it's what some riparian ecologists call \"flashy\"- much of the watershed originates in the steep Allegheny Mountains, and as water runs down steep hills faster than shallow ones, if a lot of rain falls in the Alleghenies the river will often quickly flood.\n\nIn 1785 Washington formed the Potowmack River Company. He could have advocated for a canal to be dug, but that would have been expensive in the grim times of the 1780's. Instead, it was decided to knock gaps and clear boulders through the ledges and make a channel through which boats could be floated downstream. They would have to then be dragged upstream. of course, but he thought he had an elegant solution to this. A Virginia inventor named James Rumsey had come up with a clever mechanical boat. A paddlewheel mounted on the front would work two poles back and forth, pulling the boat upstream , while two poles dangling beneath the boat would allow it to be dragged upstream, and prevent it from slipping downstream. The action would have been a little like someone cross-country skiing pushing themselves along. The faster the current, the more energy would drive the paddlewheel. Rumsey had built a small working model. Moreover, Rumsey had been working as a contractor and was willing to undertake clearing rocks from a particularly bad spot at what's now Harper's Ferry. The money he made from being superintendent would allow him to build his mechanical boat. That boat could then be an integral part of the whole Potowmack River Company scheme. What could be tidier?\n\nMost things went wrong. There was no consulting engineer- those existed in England, but canal-building in the colonies was pretty unknown. Rumsey was left to figure it out: how to lever and grapple immense rocks from the river bed and get them off to the side, how to crack ledges with gunpowder. And to do so with a large, mostly discontented crew camped in the wilderness in a temporary shanty town. Injuries were common, tempers ran high. Rumsey continually had to beg for a little more in funds and supplies, and the Company, watching every penny, was displeased to be paying for Rumsey's improvisations. His mechanical boat also had problems. If it went askew the current, it stopped running: and with the drag of a paddlewheel at the bow, it would often go askew . He had also decided to add steam propulsion, so it could also be a jet boat: but instead of a simple problem in the Newtonian physics he'd taught himself, the pump for jet propulsion produced turbulence losses beyond the knowledge of his time, and his steam engine design required far more development. After a year of frustration on all fronts, there was a bit of back-stabbing by his second-in-command, intemperate language, and Rumsey was out of a job. From there, he went on to entangle the steamboat plans of John Fitch and briefly pursue a career in England.\n\nRumsey would become known as a steamboat inventor ( to residents of Shepherdstown, WV , he would be THE steamboat inventor) . But he had started out as a millwright, building watermills. Being in the Potomac watershed, he was aware of the problem of regular waterwheels losing power when they were submerged during high water. He began thinking about a horizontal water wheel, called Barker's Wheel, that was less susceptible. He refined the design, while building his boat. He refined it more, when he arrived in England a few years later, and kept refining it. By 1792, he had created the first true [hydraulic turbine.](_URL_0_) At least one was built by his associates in Pennsylvania, but Rumsey succumbed to a stroke at the end of that year. His projects stopped, and most of his papers vanished.\n\nThe Harper's Ferry Armory was one of Washington's last development projects. He decided that the confluence of the two rivers would have unmatched water power for a big manufacturing center. After dealing with the chronically flooding Potomac for some decades, however, in the late 1840's the Armory itself decided to install seven hydraulic turbines to power its new Musket Factory. Recently invented in France, turbines were more efficient than waterwheels, and were becoming popular. Installed near where he and his crew had been hacking rocks out of the river, they looked very much like Rumsey's final 1792 turbine. But Rumsey's design was only to be seen in a patent in England, far away and forgotten, or buried in a file at the American Philosophical Society. Even his local supporters, loudly clamoring at the time for recognition of his ephemeral 1787 steamboat , don't seem to have noticed the irony.\n\nDavid Gilbert (1999) *Waterpower: Mills, Factories, Machines and Floods at Harpers Ferry, West Virginia, 1762-1991*\n\nEdwin Layton, Jr. (1989). James Rumsey: Pioneer Technologist. *West Virginia History*, v *48*\n\n#",
"Medical science is science, right? I've had a couple of chances recently to talk about one of my favourite Early Medieval English books, the medical textbook known as *Bald's Leechbook*.\n\nA Leechbook is an early medieval English medical textbook, from the Old English *Leech* for doctor. *Bald's Leechbook* is so called because it belonged to a man named Bald. The *Leechbook* is a fairly extensive medical textbook most likely produced during the 'Alfredian Renaissance' of the late Ninth Century. It contains a combination of 'classical' medicine taken from Greek and Roman works alongside more contemporary 'folk medicine' and even what we might call magic. The text is divided into internal and external ailments and is surprisingly extensive.\n\nWhile some of its 'cures' seem pointless, ludicrous or even dangerous today - cure a sick horse by leaving an inscribed dagger out for the elves, for example - many of the treatments it lists have their bearings in genuine medical science. Like many medieval scientific texts, lessons were learned from what could be readily observed around you, even if the actual scientific basis wasn't fully known. Therefore, if the placebo power of prayer improved the survivability of some ailments, for example, then prayer would be included as part of the cure.\n\nThe *Leechbook* contains not just treatments for various types of trauma, but also treatments for various illnesses and diseases: fevers, infections, liver diseases, even cancer, tips on surgery and disease control, dermatology and even tips on fertility and childbirth.\n\nWhen it comes to cuts, wounds and infections, the Leechbook first suggests that the wound be washed with hot wine and treated with a poultice including honey - both substances known to have at least mild antibacterial properties. If a wound turns gangrenous or festers, the wound would be washed out, and maybe have maggots introduced to eat the dead flesh and prevent spreading. If they felt the whole limb was in danger, they may have had to amputate, with special instruction given to cut into the healthy flesh to make sure that the whole infection was removed:\n\n > If the blackened body is so severely deadened that there is no feeling in it, then you should immediately cut away all of that dead and the unfeeling flesh up to the living body, so that there is none of the dead body as a remnant which did not feel either iron or fire beforehand.\n\n > After that one should treat the wound just like you do that part which has any feeling, and is not entirely dead. You should draw and attract the blood away from the deadened places, sometimes with frequent scarification, sometimes with great, sometimes with few, and draw the blood from the deadened place. Treat the scarification thus: take bean meal or oats or barley, or such meal as you think that it will take, add vinegar and honey, boil together and apply and bind onto the sore place. If you wanted the salve to be stronger, add a little salt to it and bind it sometimes and wash with vinegar or with wine. \n\nIf you had a fever, you might be treated with hot wine, or treated with a potion made of wormwood. Wormwood plants contain artemisinin, which is still used today to treat malarial fevers, as well as compounds used to treat parasitic worms. Wormwood is one of the most heavily prescribed herbal remedies in the whole Leechbook so must have been thought of as effective. The Leechbook contains one particular remedy which may have been very relevant: a paste for an eye infection including onion and garlic which was tested by the University of Nottingham quite recently and found to be effective in combatting MRSA.",
"Hi there, so I'd like to contribute something! About several years ago I noticed that there was a severe lack of proper material concerning Middle-eastern history (and by extension the Muslim world), so I set up a website (_URL_2_) and a subreddit (r/materiaislamica) with the help of a few redditors. I'm the chief writer for the website and my intention is to tell our own story to the world rather than it solely being told by foreigners. Here's a few articles I'd like to share that I've spent years creating: \n\n***On 165 Inventions and Discoveries Made By the Islamic World***\n\n* The first is an article regarding the **Islamic Golden Age** and it's contributions to **medicine**: ***[List of Inventions and Discoveries in Medicine During the Islamic Golden Age](_URL_0_)***. \n\n* The second is an article regarding the **Islamic Golden Age** and it's contributions to **mechanics, robotics and engineering**: ***[List of Inventions and Discoveries in Mechanics During the Islamic Golden Age](_URL_1_)***.\n\nThere are approximately ~800 citations within these articles, and you're more than welcome to explore them. They're all from highly reputable journals. I plan on writing more articles in the future, but that'll depend on time. It took me approximately 2 months working full time to create each of these articles.",
"Since I'm late to the party, I'll have to be content with posting a brief answer to a frequently-asked question: why is Roman concrete so durable? \n\nIt all comes down to material. \n\nConcrete has two basic components: aggregate (small pieces of stone or some other hard material) and lime-based mortar. Roman aggregates were nothing special. But their mortar was exceptional.\n\nBy trial and error, the Romans discovered that a kind of volcanic sand now known as pozzolana (found in large quantities in the Alban Hills near Rome) created an incredibly strong and durable mortar when mixed with lime and water. We now understand that this blend owed its qualities to remarkably strong mineral bonds ([as this unintelligible article explains](_URL_1_)). The Romans knew only that it worked, that it could harden underwater, and (eventually) that it could support vaults and domes of unprecedented scale. \n\nRoman concrete was not stronger than modern concrete (for one thing, it was not reinforced with rebar). But thanks to its peculiar chemistry, Roman concrete made with pozzolana is more durable than modern Portland cement-based varieties. The most durable Roman concrete of all was the variety used for harbor breakwaters; when mixed with salt water, pozzolana cement created [aluminum tobermorite](_URL_0_), a mineral that actually strengthens with continued exposure to the sea.",
"So who would like to talk about everybody's favorite morbid but yet unfamiliar medical topic: **Lobotomies!!**\n\nI'll preface this by saying that all of the information I share here can be found in the seminal work on early psychiatric treatment *[Great and Desperate Cures](_URL_1_)* by Elliot Valenstein. I did my master's research on the subject of psychosurgery so I have several heavily marked-up copies floating around my house. A less comprehensive but more approachable (and more widely available) option is *[The Lobotomist](_URL_0_)* by Jack El-Hai.\n\nThe first place to start is by saying that lobotomies weren't initially lobotomies. The man who won the Nobel Prize in Medicine for his pioneering invention of the procedure the *leuchotomy* was an abrasive Portuguese neurosurgeon who stole the original basis of the idea from someone else. Egas Moniz was already late in his academic life when he came across the pioneering surgical research done by John Fulton on the *frontal lobectomy* at an academic conference. A frontal lobectomy is a procedure in which you completely remove an individual's frontal lobes. That's a rather drastic thing to do, which Fulton clearly understood because he had only performed the procedure on a *chimpanzee*. Moniz took note of the surgery's results - a quieter, less psychotic subject/patient - and thought that results like that might help human patients with severe psychotic disorders. He had an in with the local mental hospital, so he had access to test subjects. And so Moniz began performing frontal-freaking-lobectomies on human subjects without their consent. After a handful of lobectomies, he determined that turning patients into *complete* zombies wasn't the ideal outcome. It certainly didn't help that most of them died within months of surgery. So instead he tried eliminating just some brain tissue by removing just *some* tissue in a procedure called a *leucotomy*. This procedure showed promise early, which was a good thing because the sanatorium where he was getting hist test subjects caught on to what he was doing and cut off his access to test subjects. Having refined the procedure he began offering it to private clients. And that is where a third-generation American doctor named Walter Freeman comes in.\n\nDr. Walter Freeman was a hardworking but rather unremarkable neurologist in Washington DC who had big shoes to fill. His grandfather was a very well-respected and widely known physician and his father had a great degree of medical respect himself. Unlike Moniz, Freeman *wasn't* callous and barbaric and, while certainly hoping to be the equal of his father and grandfather, he really truly cared about the welfare of his patients.\n\nThe picture was bleak for the mentally ill during this time and wasn't much different than centuries before. If you were lucky, you were well enough to be cared for at home. If not, you were more or less warehoused. Psychological treatment was essentially nonexistent at the time. Your family's economic means determined just how nice of a facility you were warehoused in. Given the greater disparity between classes then, chances are you were abused and abjectly neglected. Even if you weren't, you were at the mercy of your psychological demons. You suffered, and your physicians were more or less powerless to help you. And like many neurologists at the time, Dr. Freeman did not like seeing his patients suffer. This made the recent developments in the field of psychosurgery seem especially promising to doctors at the time. More on that later.\n\nDr. Freeman trained with Moniz and made the procedure more precise, with the goal of severing connections in the prefrontal region of the brain by removing corings of the patient's brain, rather than just removing giant swathes of tissue. He hit a stumbling block though - he lost his license to practice neuro*surgery* when a patient died on his operating table. So he partnered up with neurosurgeon James Watts and together they sought to provide relief from patients with a huge variety of mental, behavioral, and/or developmental problems. Freeman, however, decided that the process of anesthesia was too much a risk and that he could get the same results faster by streamlining the process. And so Dr. Watts walked into their office suite one day to find Freeman jamming what looked very much ice picks into the corners of the eyes of an unconscious (due to electro-shock) but un-anesthetized patient and sweeping them back and forth blindly, severing neural connections willy nilly. Thus ended Dr. Watts' partnership with Dr. Freeman.\n\nDr. Freeman now had what he thought to be a way to finally alleviate some of his patients' torment and he traveled across the country via an RV called \"The Lobotomobile\", sharing this method with other clinicians in an effort to do something other than warehouse them.\n\nUltimately doctors and scientists realized that the newly founded field of psychopharmaceuticals was the solution to the mental health illness crises and even the most severe cases will respond to at least some form of medication. That was the end of the era of surgical psychological treatment (mostly).\n\nSo, any questions?",
"Hi AH,\n\nI'm going to give my two cents on a few bits of earth science history. This will be from an American perspective, as Earth Sciences were notoriously parochial and regionalist before the mid 20th century, and even now haven't entirely shed that localism. The idea of continental drift, beginning with *The Origin of Continents and Oceans* is often presented as a theory with no mechanism and as a martyr against the rest of the world's scientific community. Neither of these are completely false nor completely accurate. Alfred Wegener first published his magnum opus in 1915, in the midst of the First World War. Despite being portrayed as an outsider due to his being first and foremost a meteorologist, he was not entirely a stranger to the wider earth sciences community in Germany. He had been a professor of geology before the war and had originally presented the nucleus of his continental drift theory at a meetimg of the Geological Association of Frankfurt in 1912. When *Origins* first published in English 1922, it received a foreword by John Evans, who at that point was president of the Geological Society of Lomdon. *Geologische Rundschau*, the leading geosciences journal in Germany published a paper by Wegener and an abstract was read on his behalf at a meeting dedicated to continental drift in 1926, not a particularly accepting meeting. Most of his arguments were based on similarities in paleontology between South America and southern Africa, and the strikingly similar shape of the continental slopes bordering the two. This was often misinterpreted as *coastlines* by colleagues, which led to much criticisms of his theory. Wegener's English wasn't particularly good, so it was difficult for him to defend himself from such attacks in British or American journals, which he only lived to see a few years of. A lifelong heavy smoker, he died of heart failure on an expedition to Greenland in November 1930. His body is estimated to lie under several dozen meters of ice near the center of the island. His theory's most prominent champions had been Arthur Holmes, Alexander du Toit, and Reginald Daly, who were greatly respected in their home countries. du Toit had led an expedition to Brazil and Argentina to compare fossils in those countries to his native South Africa, at the behest of John Merriam of the Carnegie Institution. du Toit published the results of his findings in *A Geological Comparison of South America with South Africa* in 1927. Merriam, an American, was not particularly happy with what he considered to be du Toit's overinerpretation and his using Eduard Suess's paradigm of sunken continents and a shrinking earth, which in much of British influenced geology, was considered something approaching scientific orthodoxy. In the United States, T C Chamberlain and his method of competing hypotheses in the field led many American geologists to reject any single theory as orthodoxy until geosynclines came into vogue in the second world war era. This was a large reason Wegener himself found less support for his ideas in the U.S. than in continental Europe or Britain, not that they were welcomed with open arms there either. Rightly or wrongly, many Americans thought Wegener to have found his theory and was going to find proof for it, evidence against it be damned. Wegener's mechanisms were indeed clunky and unworkable, but Arthur Holmes's were not. A pioneer of radiomeric dating, Holmes theorized that the earth shed heat from radioactive decay via mantle convedtion, which was responsible for horizontal motion in continents. It was a prescient theory resuscitated almost verbatim 30 years later during the plate tectonics revolution. After 10 or so years, continental drift faded from American geology until it was a footnote, a pet theory of a few academics here and there. It stayed that way until the early 1960s, when paleomagnetic data indicated a spreading seafloor in the eastern Pacific and North Atlantic, which was the genesis of the modern plate tectonics model. A few of the founding fathers of plate tectonics gave a look back 40 years at Wegener and Holmes, but as a quaint afterthought who were half right, which was selling them far short. Luminaries like Harry Hess, Teddy Bullard, and Maurice Ewing were beginning their formative years in the late 1920s, when the controversy over continetal drift was at its peak. All three of them were on several expeditions led by Felix Vening Meinesz in the 1920s and 30s to measure gravity anomalies in the Gulf of Mexico. Vening Meinesz had originally become interested in marine gravimetry in the Java Trench, which he became interested in via some of Wegener's supporters positing the area as a convergence of two great crustal slabs. American geodedicist William Bowie, whose feelings for drift ranged from neutral to negative, invited him to the United States and the expeditions to the Gulf and Caribbean followed.\n\nLeGrand, Homer and Oreskes, Naomi, eds (2001) *Plate Tectonics: an Insider's History of the Modern Theory of the Earth*\n\nOreskes, Naomi, (1999) *The Rejection of Continental Drift: Theory and Method in American Earth Science*"
]
}
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[] |
[] |
[
[],
[
"https://www.reddit.com/r/AskHistorians/comments/5hq6dx/sunday_digest_interesting_overlooked_posts/db2asfo/",
"https://www.youtube.com/watch?v=HU7Ga7qTLDU"
],
[
"https://www.nobelprize.org/prizes/economic-sciences/2009/ostrom/facts/",
"https://en.wikipedia.org/wiki/Tragedy_of_the_commons"
],
[
"https://en.wikipedia.org/wiki/Biot_number",
"https://en.wikipedia.org/wiki/Laplace_distribution",
"https://en.wikipedia.org/wiki/Gay-Lussac%27s_law",
"http://johnworrall.org/wp-content/uploads/2018/09/1989-Fresnel-Poisson-and-the-White-Spot.pdf",
"https://en.wikipedia.org/wiki/Poisson_distribution"
],
[],
[],
[],
[],
[
"https://imgur.com/a/XEw3vPg"
],
[],
[
"http://materiaislamica.com/index.php/List_of_Inventions_and_Discoveries_in_Medicine_During_the_Islamic_Golden_Age",
"http://materiaislamica.com/index.php/List_of_Inventions_and_Discoveries_in_Mechanics_During_the_Islamic_Golden_Age",
"http://materiaislamica.com/index.php/Materia_Islamica"
],
[
"https://cedar.wwu.edu/geology_facpubs/67/",
"https://www.pnas.org/content/111/52/18484"
],
[
"https://www.amazon.com/Lobotomist-Maverick-Medical-Genius-Illness/dp/0470098309/ref=pd_lpo_sbs_14_t_0?_encoding=UTF8&psc=1&refRID=NQ0BH6NT5G3BEYA5ABMF",
"https://www.amazon.com/Great-Desperate-Cures-Psychosurgery-Treatments/dp/1452820422"
],
[]
] |
|||
78jrjn
|
Can an insect be “fat”? How do they store energy?
|
How long can an insect go about it’s business on its reserves?
|
askscience
|
https://www.reddit.com/r/askscience/comments/78jrjn/can_an_insect_be_fat_how_do_they_store_energy/
|
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"It depends a lot on the insect in question.\n\nThe most extreme example I can think of is the [honeypot ant](_URL_0_). Some members of these colonies become living food storage for the rest, hanging in place and taking in or giving out their stored reserves as needed. ",
"Bloodsucking insects will become engorged after feeding. Mosquitos, bed bugs, lice, ticks, fleas, ticks (arachnid), are visibly larger after feeding.\n\nPerhaps more relevant is the Fat Body.\n\nInsects have an organ called the Fat Body. Lipids (fats) are stored here in adipocytes in the form of triglycerides (same way mammals store fat, essentially). These lipids are consumed during periods of high energy demand (like when flying), and are replenished in periods of food abundance. \n\nSome insects have been shown to increase the size of the Fat Body in the winter, as a mechanism to enhance survival. Other insects (like house flies) don't seem to be able to store extra fat. \n\nedited to add some sources: \n\nStudy on fat storage in Culex pipiens: _URL_0_\n\nreview paper on the insect Fat Body:_URL_1_",
"Many insects have a part of their lifecycle dedicated to collecting and storing energy and another part where they can't collect energy, and can only live off of their stored reserves. Lots of species of moth spend their larval stage eating, then form a cocoon and emerge as an adult without a digestive system at all. Their adult stage is dedicated to mating and laying eggs, which will hatch into larvae and repeat the cycle.",
"_URL_0_\n\nThis video (particularly around 10:30) shows the fat on a mantis very clearly.\n\n_URL_1_\n\nThis one shows a different mantis with much less fat, though still has some. I would say that both of these videos are fairly useful for understanding insect anatomy. Good visual aids.\n\nPoint being, insects do store fat within their exoskeleton.\n\nAs for how long an insect can go on its reserves, that largely depends on the species. Some insects, like cockroaches, can live for multiple months without eating anything at all. Other insects must eat much more frequently.",
"There are several answers suggesting that insects store fat in the same way humans store long chain hydrocarbons. The insect process is different. Please read the attached article, specifically the part about vitellogenin in insects.\n\n_URL_0_",
"Not sure whether you're still interested in yet another person telling you, but here I go:\n\nInsects have an organ called the fat body, which is located on the ventral side of the abdomen. This is a kind of functional equivalent of the liver and is also used (as the name suggests) to store fat as an energy reserve.\n\nIn our experiments, we could always very clearly see the difference between fat bodies of starved vs non-starved locusts.\n\nFat isn't only stored in the fat body though. While that's the main site of storage, you can also see fat in all body cavities.\n\nThe reason why an insect doesn't get literally fat is because they are often filled with air sacs, filling the body cavities. When the organs grow (because of fat storage, production of eggs,...), these air sacs simply deflate and become smaller.\n\nFinally, there is a large difference between insects, and logically also a large difference in the time you can starve an insect. Our locusts could easily make it two weeks without any food. Several of them would make it over a month.",
"There seem to be two main ways insects store food - by storing the liquid in their digestive system, or by incorporating fat into their system. The liquid method seems very popular in social insects, particularly ants and wasps, because it can be regurgitated at a moment notice to share with nestmates. \n\n[I remember reading](_URL_0_) an post on fat katydids - true fat stored in fat cells. Fat is not as clearly visible in insects as it is vertebrates, but some species that have to undergo hibernation or periods of starvation do use it to their advantage, and they definitely are heavier and fatter than when without their fat stores - insect exoskeletons are a lot more flexible than people give them credit for.",
"During a cockroach dissection in university biology labs I recall noticing how much fat they had inside their bodies. It's just packed inside the rigid shell, although presumably if they get fat enough they moult to increase the available space.",
"Insects have limited capacity to store energy due to there size, so they basically have to be constantly eating in order to stay alive. Their surface-to-volume ratio is much higher than that of a human so heat dissipation will be much faster and also their metabolic rate will be much higher due to their size (look up metabolic scaling - interesting fact, every living creature typically has the same number of heart beats in a life time it's just smaller creatures tend to have a faster heart beat hence why insects live for a matter of days and elephants closer to a hundred years). ",
"I work at an Insectarium. The answer is a resounding YES. We take very good care of our arthropod guests and some of them don't get the amount of exercise they would in the wild. Currently we have an obese praying mantis, tailless whipscorpion, and centipede, just off the top of my head. \n\nAll arthropods have areas of membrane between their sclerites (the panels of exoskeleton) and when they have so much fat body (insects equivalent to our fat storage, it also does other things) that their sclerites aren't anywhere near touching anymore and their semens of membrane are stretched thin... they are fat. I'm pretty sure we have some that would be in the obese range if there was a scale for insects.",
"They definitely can get fat. If anyone here keeps reptiles you might know about gut loading, when you essentially keep inverts and fatten them up before you feed them to the reptile to give them more nutrients in their diet. ",
"Nematode biologist here (not an insect, but may be informative nonetheless):\n\nEven very simple animals, like a 1,000-celled nematode (roundworm), store fat. In roundworms, many of the proteins that synthesize fat are similar to those in humans. Also, some conditions, like low food availability or high population density, cause worms to enter hibernation, and these animals store more fat to compensate. So yes, very simple animals can store fat and use it as an energy source in a similar way to mammals.",
"I had a praying mantis. Got pretty fat. Was a happy mantis. But only the abdomen swells. They get to their normal weight some days later. Takes a lot less time then for humans and doesnt really harm them.\nThey can eat nearly their one body weight at once. \nAcutally had 2 after another and the guy that followed at an adult argentinian wood roach which is about 4-5 cm in lengh while hanging upside down in a timespan of pretty much exactly 24 hours. He wasnt even fully adult at this stage and about 6-7 cm big. \n"
]
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[
[
"https://en.wikipedia.org/wiki/Honeypot_ant"
],
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"https://www.ncbi.nlm.nih.gov/pubmed/2769712/",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3075550/"
],
[],
[
"https://www.youtube.com/watch?v=VqMijWK9ZOc",
"https://www.youtube.com/watch?v=pMbQ4-mrsZM"
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[
"http://www.sciencedirect.com/topics/neuroscience/vitellogenin"
],
[],
[
"https://thesmallermajority.com/2013/09/12/mozambique-diary-the-fat-coneheads-of-gorongosa/"
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6rc5t0
|
Does a multi-decade concentration of Radon gas lead to an accumulation of lead particles in an enclosed environment (basement)?
|
I was looking at [the decay chain for Radon](_URL_0_), and noticed that the first stable element in the chain is lead 210.
So if a basement, for example, has high Radon levels for, say 100 years, would that create a higher than normal concentration of lead in that enclosed environment?
|
askscience
|
https://www.reddit.com/r/askscience/comments/6rc5t0/does_a_multidecade_concentration_of_radon_gas/
|
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"We're talking about concentrations that would be nearly undetectable if the substances weren't radioactive. Let's run some numbers.\n\nThe highest recorded residential levels of radiation from radon and its decay products have been on the order of 100,000 becquerels of activity per cubic meter of air, where 1 Bq is defined as one atom decaying per second.\n\nFor simplicity, we'll pretend that each atom is removed from the sample as soon as it decays to lead-210, and radon is added as necessary to keep the activity at 100k Bq/m^3.\n\nFor one atom to go from radon-222 to lead-210 is a total of five decays: three alpha and two beta. Dividing our 100,000 decays per second by five decays per atom, we get 20,000 atoms of lead per cubic meter per second.\n\nNow, applying that rate to a 50-m^3 room for 100 years (3.154 x 10^9 seconds), we get 3.154 x 10^15 atoms of lead, with a total mass of about a microgram.",
"Likely not as there is more lead present from other sources. On terms of meaningful quantities of things, a block of lead contains on the order of a \"mol\" of atoms ~6 *10^23 this many radon atoms decaying over 10 years would produce so much radioactivity everyone in the house would be dead if they ever went down there. ",
"SO, for starters, 4pCi/L is equal to 0.148 decay events per second per liter.\n\nSo that is 148 decays per second per cubic meter per second.\n\nNow lets go with your question in the op and ask, ignoring the half lives of the intervening steps on the decay chain, how much lead is produced per cubic meter of volume in a basement with this activity level over the course of 100 years?\n\nSo, 148 decays per cubic meter per second, 148 decay/(m^3 x sec).\n\n148 decay/(m^3 x sec) x 60 sec/min x 60 min/hr x 24 hr/day x 365 day/yr x 100yr = 4.667x10^11 lead atoms per cubic meter of basement volume.\n\n4.667x10^11 lead atoms = 7.750x10^-13 moles of lead = 1.604x10^-10 grams of lead\n\nSo. At 4pCi/L Radon activity for 100 years, you will be left with 0.1604 nanograms of lead per cubic meter. Or 0.1241 parts per trillion airborne lead contamination.\n\nAccording to the [CDC](_URL_0_) 15 parts per billion is the max allowable in drinking water, so the basement air is around 10,000 times less contaminated that what is considered max safe to drink.",
"I am confused about radon. I know it is the densest gas, but is it possible for a gas to be so dense that an uncompressed bucket of it would be noticeably heavier than an empty one?\n\nIf you had a decent amount of radon all in one place, what would it look like? Would it be a sort of glowing cloud until it dissipated? Would it feel warm? Painful to stick your hand in it?",
"I guess i can actually help you with this! I have pleasure of working on LNG tankers, we load and discharge refrigirated methane on a regular basis, however it is not pure 100% methane, there are traces of other gases loaded in the mix, and one of them is... Radon gas. So in line with your reasoning we should see a lot of lead 210 in our tanks. And do we? Yup, we actually have to test the tanks for lead 210 residue before entering cargo tanks, lead 210 tends to form a dusty layer on the surface of the cargo tanks and all of it comes from decayed Radon gas. I hope this helps! I can talk about this for hours...",
"Once the radon decays by alpha decay, the daughter polonium will be slightly ionized, and it almost immediately attaches to a dust particle (of any size). You can filter out the dust, and the attached daughter products, but obviously the reduction depends on the efficiency of the filter and what size dust you have. Plus the radon is continually adding more daughter products.\n\nThe decay to Pb-210 is energetic enough to physically embed the lead atom into surfaces. You can measure historical levels of radon by looking at glass that's been in a location for decades and figure out the average radon concentration.\n"
]
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[] |
[
"https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Decay_chain%284n%2B2%2C_Uranium_series%29.svg/350px-Decay_chain%284n%2B2%2C_Uranium_series%29.svg.png"
] |
[
[],
[],
[
"https://www.cdc.gov/nceh/lead/tips/water.htm"
],
[],
[],
[]
] |
|
39yn7o
|
Book suggestion for the 1933 coup, and the 1959 revolution?
|
Any help would be greatly appreciated.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/39yn7o/book_suggestion_for_the_1933_coup_and_the_1959/
|
{
"a_id": [
"cs7mz9n"
],
"score": [
2
],
"text": [
"You may want to specify the country in your OP: some flaired users have auto-notifications set up for certain key words"
]
}
|
[] |
[] |
[
[]
] |
|
3cmpxa
|
developing grey hair at a young age
|
I'm currently 16 and had found out not too long ago a bit of my hair has been starting to go greyish and one or 2 strands of hair are completely silver. I know it doesn't come from my family I've heard and read that the cause for this would be lots of stress and whatnot but I'm not sure if I can rely on that. Little bit of help here understanding?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3cmpxa/eli5_developing_grey_hair_at_a_young_age/
|
{
"a_id": [
"csx01wt",
"csx1upt",
"csx4kvs",
"csx65b4",
"csx8ao4"
],
"score": [
15,
3,
5,
3,
4
],
"text": [
"Mine's genetic, but not as bad as my grandfather. He went completely grey by 20. Me, I'm salt and pepper right now. I don't mind though. Better to have hair than no hair. If it's that big of a deal, you could dye it.\n\nBut, to answer your question:\n\n1. Stress has not been shown to increase greying (but I tend to think it does. No proof though).\n\n2. a vitamin B-12 deficiency or problems with your pituitary or thyroid gland can cause premature graying that’s reversible if the problem is corrected.\n\n3. Scientists aren't really sure why, but it tends to be genetic.",
"I have five brothers and sisters. All of us except one were pretty much totally grey by the time we were 35 years old. So I'd say it's genetic. The good news is, we have *no* baldness in the family at all. One recommendation - if you truly find out that you are going grey at an early age, start dyeing your hair early *especially* if you're male. It may not be fair, but guys are viewed more negatively if they suddenly dye their hair after being completely grey for a while.",
"Trauma can cause grey hairs in the area where the injury occurred. My friend hit his head on a fireplace when he was 4 or 5 and has about a 1 inch diameter circle of grey hair. ",
"I'm 35 now and my 80% of my hair is white (not grey), just plain white! Started turning white when I was 16 or 17. I have a crew cut so it's also a pain to dye black because the colour sticks to my scalp if im not careful :D .\n\nI reckon I got this from my mother who said that her hair started turning white at an early age. ",
"Mine's genetic, and the thing is called vitiligo. When you have it your skin cells become unable to produce pigment, not all of them, just in patches. The patches can grow, or not. I noticed it begin during puberty. Any hair in the patch will have no pigment either and will be transparent from the point the cell lost it's ability to produce pigment, so you can get a sudden colour change mid-hair. The transparent hair's look will vary based on the colour of the normal surrounding hair. If you are white skinned you may not have noticed the patches of skin without pigment, no one ever notices mine, but I can see them. If you are black, then you still end up with completely white patches, so it would be obvious, unless this is just starting for you. \n\nIf it is vitiligo, then you are at a higher risk of skin cancer as those patches cannot tan to protect the nucleus of your cells, so you have to be extra careful in sun."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
|
10kmuj
|
Why did the Australopithecus become extinct?
|
Is there a reason why they are not still around today? I'm sorry if this is a silly question, I haven't covered evolution in school yet so I really don't know much about anything, but I just thought - if the chimps and apes are still around today, why aren't they?
|
askscience
|
http://www.reddit.com/r/askscience/comments/10kmuj/why_did_the_australopithecus_become_extinct/
|
{
"a_id": [
"c6eaj7k"
],
"score": [
7
],
"text": [
"Of all of the primate human ancestors it could be said that they met one or a combination of three fates:\n\n* Evolve and occupy a separate niche which does not compete with what became human\n* Interbreed with what became human\n* Compete for resources and lose against what became human\n\nIn other words they either fought us, joined us, or ran away."
]
}
|
[] |
[] |
[
[]
] |
|
39ryvj
|
Why does sand express the same properties of a non-Newtonian fluid when wet? Is it a non-Newtonian fluid?
|
askscience
|
http://www.reddit.com/r/askscience/comments/39ryvj/why_does_sand_express_the_same_properties_of_a/
|
{
"a_id": [
"cs62t3b"
],
"score": [
3
],
"text": [
"Yes, a non-newtonian fluid acts like a solid when a force is applied because the particles of sand (or corn starch, etc) restrict the flow of water when pressure is applied. Additionally, the surface tension of the water keeps the particles bonded together as a cohesive unit."
]
}
|
[] |
[] |
[
[]
] |
||
5urrvc
|
Is there a charge for the weak force?
|
The other three fundamental forces all seem to have charges which act as sources and/or sinks of flux. Electromagnetism has electric charge, gravity has mass and the strong force has colour. So is there a charge for the weak force?
|
askscience
|
https://www.reddit.com/r/askscience/comments/5urrvc/is_there_a_charge_for_the_weak_force/
|
{
"a_id": [
"ddwnuzg"
],
"score": [
18
],
"text": [
"The equivalent of charge and colour for the weak force is flavour, with a caveat (edit: more precisely, weak isospin, as corrected below). Typically, flavour refers to the 6 different kinds of quarks and the six different kinds of leptons, but they're organized in 3 groups of two, with each group, called a generation, having a \"up-type\" and a \"down-type\" quark, or a \"electron-type\" and a \"neutrino-type\" for the leptons. Really, it's the difference between up-type and down-type that is the equivalent of charge, while the difference between generations is a separate concept. \n\nElectromagnetism has one type of charge, which can be positive or negative, while the strong force has three, each of which can be positive or negative (red/green/blue, anti-red/anti-green/anti-blue), while the weak force has two kinds which can be positive or negative (up-type/down-type, anti-up/anti-down).\n\nThe reason we don't usually think of flavour as a \"charge\" in the sense of electromagnetic charge and colour-charge is becuase of electroweak symmetry breaking and the Higgs mechanism. Each kind of charge corresponds to a different kind of gauge-symmetry, but in the case of the weak force the gauge symmetry is broken at this time and place in the universe. This breaking of the gauge symmetry along with the Higgs mechanism has resulted in the types of particles with different flavour-charge getting different masses, and so we think of them as different kinds of particles. With electromagnetism and the strong force, electrons and positrons have the same mass, as do quarks and antiquarks of the same flavour but different colour. So, the different charges don't change the particle type, and this is related to the fact that the gauge symmetries in those cases is unbroken."
]
}
|
[] |
[] |
[
[]
] |
|
4y1eq0
|
what is it like behind the scenes when a major website or video game has a massive crash?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4y1eq0/eli5_what_is_it_like_behind_the_scenes_when_a/
|
{
"a_id": [
"d6k4s84",
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"score": [
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"text": [
"Panic from everyone non-technical and loud sighs from all of the developers/network guys.\n\nIt's usually a straight-forward fix, so the tech people see \"work at off-hours that I don't get paid for because I'm salary\" and all of the business people see some super complex world-ending problem that they have no idea how long will take to fix.",
"I've had experience of working in large banks and trading organisations, and we have special \"disaster recovery\" procedures in place. I assume other areas where technology is so vital are similar.\n\nBasically, all of the essential systems are duplicated, in an office a few miles down the road (so it's unlikely that our main office and our disaster recovery office are unlikely to be both affected by a power cut, internet outage, etc at the same time).\n\nI've done many practice runs. It's a pain, but it's well rehearsed. The business used to hate it because they only had the absolute minimum of systems. We once had a genuine power outage, and they were very reluctant to go to disaster recovery in case it was only a short outage. In the end, the power came back on before they'd made the decision, so of course that made the decision for them.",
"Outages and defects are pretty common. What's less common are big show-stopping bugs, bugs that run in the thousands or tens of thousands of dollars per hour of downtime. When our system detects an outage a call goes out to a member from each team that carries a prod support phone at all times. We have a scale that rates incidents based on the total expected dollar impact per hour/day. Basically we just multiply the number people affected and the expected revenue per person. For the highest priority issues you get 15 minutes to get online and join the conference call. Teams will quickly determine if they are impacted by the issue and most will drop off after a couple minutes if they are not affected. From there the remaining people on the call will try to diagnose the problem and devise a fix. Sometimes the issue can be fixed with some small tweaks and the changes are made, tested, and moved to production within a couple hours. We may determine the issue really isn't that big of an issue and fix it with the next scheduled release. We may develop some quick and dirty temporary workaround until the problem can be fixed properly. If the issue is large enough we may even escalate the issue and call people in to develop an immediate solution and do an emergency release to production ASAP."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
9tz0un
|
Are there dangerous retroviruses in vaccines?
|
To clarify: no, I am not remotely an anti-vaxxer. I’m asking this because I found out yesterday that my ‘alternative medicine’-practising uncle is and I was *livid*.
He was watching some expert on TV talking about how it might be worth considering forcibly vaccinating children, and he cursed her aggressively and said she was harming kids or some nonsense like that. I got really mad and started arguing, and when my tone got a bit aggressive asking him to actually cite anything he says, he said I was being ‘violent’ just because he voiced a ‘different opinion’. He tried to point me towards research by [Judy Mikovits](_URL_2_), so I did a bit of research on her, and found [this article](_URL_0_), where she is one of the researchers refuting the claim she was making, but he claimed it had been done without her consent and under duress, talking about all sorts of threats or whatever she got to recant. (He also told my father some stories about dissenting ‘doctors’ dying under all sorts of strange circumstances, which sounded quite a lot like [‘Clinton body bags’ bullshit](_URL_5_). Naturally, I asked him if she was getting those threats from George Soros and Reptilians.)
Anyway, he swears by PubMed specifically as a reliable source for medical info, so I tried Googling ‘retrovirus vaccines PubMed’¹… and I found the above mentioned article, which seems to support his claims on the presence of harmful retroviruses in vaccines.
So now I would really like some counter-arguments I could use to stop him from endangering the lives of children, because from what he and my father keep saying, he’s unusually popular and people from all over the country come to see him. (Fortunately enough, this is Israel, so that’s not a lot of people from not a lot of country, but still.)
¹Googling other keywords, I found stuff like [this](_URL_4_), [this](_URL_7_), [this](_URL_1_) (from PubMed), [this](_URL_8_) (from a Scandinavian journal—I’d told him I trust Swedish doctors in particular because they don’t get funding from pharmaceutical companies), and [this](_URL_3_), and a good friend of mine who happens to have a PhD in biochemistry found [this](_URL_6_). However, what I managed to find on PubMed specifically are other articles supporting his claim, mostly from several years ago. I know he’s moving the goalpost and accepting a ridiculously low burden of proof for his own claims, but if it stops him from endangering the lives of children, I’ll grind my teeth and play along.
|
askscience
|
https://www.reddit.com/r/askscience/comments/9tz0un/are_there_dangerous_retroviruses_in_vaccines/
|
{
"a_id": [
"e92yuh9"
],
"score": [
3
],
"text": [
"Unfortunately you may find it hard to reason with some people, even with good sources. My own father has a degree in Geography yet refuses to believe in man made climate change. Remember, for his theories such as Judy Mikovits being under duress it is his responsibility to get evidence for it. \n\nAnyway, here are some studies: \n\n[No Evidence of Infectious Retroviruses in Measles Virus Vaccines Produced in Chicken Embryo Cell Cultures](_URL_0_)\n\n[No Evidence of Murine Leukemia Virus-Related Viruses in Live Attenuated Human Vaccines](_URL_2_)\n\nKeep in mind there is evidence of finding endogenous retroviral DNA in some vaccines: these are ancient viruses that now make up the genome and come from the vaccine production in certain cell lines. In vaccines they will be attenuated as no retroviral RNA has been found in the blood serum of vaccinated people. [See this study, which found retroviral RNA in the vaccine, yet found no retroviral activity in those inoculated](_URL_1_).\n\nApologies as virology is not my strong suit.\n\nIt might be easier to try and explain that the ridiculously low risk of vaccination is worth it when compared to dying of a preventable disease. If however, he believes in things like Government mind control/tracking vaccines etc, it will be immensely difficult to make him see reason. Good luck and I appreciate your efforts in trying to help him turn away from the anti-vax movement. "
]
}
|
[] |
[
"https://mbio.asm.org/content/3/5/e00266-12?sid=2c5ce94a-a8f4-404a-8e6e-6389779bb93e",
"https://www.ncbi.nlm.nih.gov/pubmed/26683689",
"https://en.wikipedia.org/wiki/Judy_Mikovits",
"https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029223",
"https://www.ncbi.nlm.nih.gov/pubmed/21427399",
"https://www.snopes.com/fact-check/clinton-body-bags",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5439170",
"https://www.ncbi.nlm.nih.gov/pubmed/22561998",
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3171704"
] |
[
[
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC87796/",
"https://www.ncbi.nlm.nih.gov/pubmed/12502826",
"https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029223"
]
] |
|
42ggdf
|
what happens to wildlife in a blizzard?
|
Animals that do not hibernate, like deer: how do they cope with 2-3' of snow, and drifts?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/42ggdf/eli5_what_happens_to_wildlife_in_a_blizzard/
|
{
"a_id": [
"cza4a5n",
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],
"score": [
47,
33,
5
],
"text": [
"More deer do die during really bad winter conditions, but it's surprising how ridiculously tough they are. During the end of fall they undergo a number of bodily and behavior changes: they eat way more food to pack on insulating layers of fat, they shed their summer coats and grow a winter hide of hollow fur that traps air and insulates them further. During particularly bad weather they actively seek out shelter and herds/family groups conserve energy by not moving much. Like two thirds of their time or more is just spent bedded down sleeping.\n\nSmaller mammals tend to go underground in the winter.",
"I can't speak for all animals, but birds that live near water will desperately look for any open waters. As such around holes in the ice you will find many species of duck, gulls, cormorants, swans, geese, kingfishers, herons, bitterns, snipes, etc. It is a great time to look for birds that are usually hard to find such as Jacksnipes and Bitterns, they will come out of their hiding and flock towards such holes. There is one little creek in my village where the water is running and doesn't freeze and once I found over 10 Jacksnipes just along this creek. Normally they are extremely hard to find because they have [near perfect camouflage](_URL_0_).",
"Small mammals just stay in burrows until the ice and snow melts; however, there are places where the bottom of the snow melts before the top, creating tunnels and spaces in the snow where they can move around in. I'm not sure if this happens everywhere."
]
}
|
[] |
[] |
[
[],
[
"http://i.imgur.com/QMUm8UH.jpg"
],
[]
] |
|
1vufgd
|
why does law enforcement need a warrant to search a suspects property? and why is evidence acquired without a warrant inadmissible?
|
Lets say law enforcement officials find conclusive evidence that somebody committed a heinous crime, the evidence however was acquired without a warrant, why is it inadmissible? isn't this injustice? how could a criminal walk free for such a technicality?
Edit; Thanks all, great answers!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1vufgd/eli5_why_does_law_enforcement_need_a_warrant_to/
|
{
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"text": [
"The law is there to protect everyone, including the guilty. Look up the bill of rights, and the amendment which protects you against unwarranted search and seizure.\n\nRemember these laws were written at a time when the people had very recent experience of a government which was corrupt and did not have its citizens best interests at heart.\n\nThe law was written to ensure that all people were presumed innocent, that they had a right to privacy, and that your belongings couldn't be searched unless someone had been able to convince a judge that they had reasonable suspicion of a specific crime being committed. And not just \"he looked dodgy\"",
"It's inadmissible so that cops won't be encouraged to do illegal searches. It's to protect innocent people from just having cops bust down their doors on the off chance that they find something.",
"It's not difficult to get a warrant, and sometimes [exigent circumstances](_URL_1_) allow for entering a residence to secure the site to allow time for a search warrant to be authorized. There are likely very few instances (outside of movies) where inadmissable evidence causes a case to get thrown out.\n\nOn the plus side, it does prevent police from randomly searching everybody on the street ([New York City's stop and frisk is an ongoing exception)](_URL_0_).",
"Interestingly enough, the Constitution says nothing about evidence being obtained illegally being inadmissable. All it says is that police require a warrant to search someone's property, but makes no mention of the penalty for not complying.\n\nThe reason the evidence is not admissible is because of the Supreme Court case of Mapp v Ohio, in which the police tried to get a woman to allow a search of her house with a fake warrant. When she refused, she took the fake warrant and shoved it down her shirt. The police forcibly removed the paper from her bra and proceeded to search her place anyway, not finding the evidence they were expecting, but instead finding illegal pornographic material. The court ruled for the first time that evidence obtained illegally is inadmissable in court so the police were disincented to pull stunts like that again."
]
}
|
[] |
[] |
[
[],
[],
[
"http://en.wikipedia.org/wiki/Stop-and-frisk_in_New_York_City",
"http://en.wikipedia.org/wiki/Exigent_circumstance_in_United_States_law"
],
[]
] |
|
75tqvr
|
how is it economical to ship ramen packets?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/75tqvr/eli5_how_is_it_economical_to_ship_ramen_packets/
|
{
"a_id": [
"do8w199",
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],
"score": [
5,
8
],
"text": [
"Based on their 2016 quarterly report, it costs Maruchan $2.15 billion to generate $3.40 billion in sales.\n\nThey're spending $0.157 to get that $0.25. It takes 3.6 billion packets of Ramen and a whole host of higher margin foods to do it nine cents at a time, but they're apparently pretty profitable.",
"It probably costs a *lot* less to ship things than you think.\n\nLet's say it costs about $2000 to ship a 20ft container from Asia to the US. That's [1100 cubic feet of space](_URL_0_).\n\nLet's also call a [12-count of ramen](_URL_1_) is about 0.23 cubic feet.\n\nDoing some math, that gives 5100 cases or 61,200 packets of ramen - about 3c per packet of ramen.\n\nYou also need to keep in mind that several brands are made in the US, cutting out that cost entirely."
]
}
|
[] |
[] |
[
[],
[
"https://www.sjonescontainers.co.uk/container/dimensions.asp",
"https://www.walmart.com/ip/Maruchan-Chicken-Flavor-Ramen-Noodle-Soup-12-3-oz-Box/10450904#read-more"
]
] |
||
6biot3
|
Is the radiation from a microwave oven considered a photon?
|
askscience
|
https://www.reddit.com/r/askscience/comments/6biot3/is_the_radiation_from_a_microwave_oven_considered/
|
{
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"text": [
"A classical light wave is not a photon. It's a coherent state with indefinite number of photons. You can't say exactly how many photons there are, it's in a superposition of different photon numbers. The probability distribution for the number of photons is a Poisson distribution. So you can talk about the average number of photons. In the limit where the mean of the Poisson distribution becomes large, it behaves like a Gaussian distribution with the same mean, and with variance equal to the mean. So the relative fluctuations in the number of photons goes like sqrt(N)/N = 1/sqrt(N). For large N, the relative fluctuations are small.",
"Yes!\n\nRadio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays. Every kind of radiation in the electromagnetic (EM) spectrum are pretty much just a bunch of photons.\n\nAnd what really distinguishes those regions in the EM spectrum is the energy of the photons.",
"It's a stream of photons, yes. If the average photon has an energy of about 1.65-2.00 electronvolts (eV, a unit of energy) we call it \"red light\", if it's 2.75-3.26 eV we call it \"violet light\", if it's got 0.000001 eV to 0.001 eV we call it \"microwave\". There is no difference beyond that, \"microwaves\" are just light of much lower energy than visible."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
4xbtrq
|
what are the differences in antibiotics that are designed for different varieties of infection (viral, fungal, bacterial, etc.) ?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4xbtrq/eli5_what_are_the_differences_in_antibiotics_that/
|
{
"a_id": [
"d6e5hgr",
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],
"score": [
7,
2
],
"text": [
"Antibiotics are *only* for treating bacterial infections. That's literally what the word means.\n\nIf you're looking at treating fungal infections, you need an antifungal. If you're looking to treat a viral infection, you need an antiviral.\n\nThey're all completely different drugs.",
"Antibiotics treat bacterial infections only. \n\nAntifungals treat fungal infections. \n\nAntivirals treat viruses, if they can be treated at all. \n\nThey are all different drugs and do different things. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
7y8rxt
|
How diverse was Bohemia during the fifteenth century?
|
There's been some controversy about the new PC game Kingdom Come: Deliverance not including people of color. It's historically set in Bohemia in 1403. Just how diverse was that region at that time?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7y8rxt/how_diverse_was_bohemia_during_the_fifteenth/
|
{
"a_id": [
"duehir0"
],
"score": [
5
],
"text": [
"Hi, not discouraging more info here, but FYI there was a popular thread on this a couple of weeks ago, featuring /u/commiespaceinvader among others \n\n* [People are getting extremely upset because there are no black people in Kingdom Come: Deliverance. How accurate is this for 16th century Bohemia?](_URL_0_) "
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/7v1lil/people_are_getting_extremely_upset_because_there"
]
] |
|
1jc9oe
|
machiavellianism
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1jc9oe/eli5_machiavellianism/
|
{
"a_id": [
"cbd983t",
"cbd9dlz",
"cbd9pr9",
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"cbefoio"
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"score": [
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6,
120,
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3,
2,
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2,
2
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"text": [
"1. Always have an out, even if it means sacrificing those closest to you. \n2. The ends justify the means. \n3. All things being equal, fear is a better tool of power than compassion. \n4. What your subjects think of you means little so long as you retain your power to rule. ",
"_URL_0_\n\nMachiavelli was a man who studied and wrote about power and how it could be attained and retained. His book 'the prince', see link, is probably his most famous work on the matter and is basically a retelling of how powerful men he encountered or studied kept their power and how successful they were when trying different methods (love/hate/fear/gratitude) to keep their subjects in line.\n\nIt gets such a good run as its about results without any judgement for how those results are obtained. \n\nThink of it as the idiots guide to ruthless ambition.",
"Machiavelli is best known, and the term which now bears his name comes from, a book he wrote called *The Prince*. In it he explains clearly to the rulers of his day how a prince, the ruler of a city-state, should act. He gives advice on a range of topics, but in general it all comes down to a few key rules.\n\nFirst: it isn't important what you do, only how you are seen. A prince must be believed to be trustworthy, faithful, and just. He need not actually be any of those. In fact he should not be. \n\nWhich brings us to the second rule: do whatever you must whenever you must. A prince takes whatever course of action best maintains or increases his power. If you see an opportunity you take it, if something is a threat eliminate it.\n\nThird: your subjects are both the greatest power and greatest threat you have. Treat them as such. You must ensure that they will never try to remove you and that they will obey you. It is best to be both feared and loved, but if you must choose one be feared. Feared but not hated. If people hate you they will remove you, if they fear you they will obey you. To ensure fear but not hatred follow the same rule for those you must remove at home as you follow for those you must remove in war.\n\nFourth: both in war and at home destroy your enemies completely. Those you must destroy will hate you and seek revenge if they can. Do not leave them able to. When you finish they should have no capacity to harm you left. But do not damage in any way others, you will make new enemies that way.\n\nFifth: never trust others. Do not trust your allies as a state. Do not trust mercenaries as an army. Do not trust advisers as a man. Everyone has their own agenda, it is never the same as yours. Know what they want and you can use them. Never believe that they want what you want.\n\nSixth: above all else never get involved in a land war in Asia.",
"Machiavelli was a large proponent of ends justifies the means, and I would say that when you talk about him in political philosophy, this is what you would be referring to.\n\nHowever, in common usage, it means someone who can be two-faced or duplicitous in servicing their own ambitions. ",
"As a former student of political science and someone who wanted to work in politics, some of the best advice I ever got was the following:\n\n1. Read Saul Alinsky's \"Rules For Radicals\" to understand how to get power when you don't have it\n2. Read Machiavelli's \"The Prince\" to learn how to maintain power once you've got it\n",
"He also said that the strongest walls are the love of your people. I feel that no matter who is in charge, as long as life is stable and promises to improve, people don't care.",
"[If I could say one thing to Machiavelli...](_URL_0_)",
"I think Machiavelli might have gotten a bad wrap. The Prince is how people are describing it, but viewing it within the time it was written might betting explain how Machiavellian is a pejorative term today. \n\nIn the Prince Machiavelli dares to state two things that were blasphemous and way ahead of their time.\n\nA. That political power is ultimately derived from popular support. Power coming from the will of the governed is accepted more or less throughout the modern world, but it was a radical idea at the time, and Machiavelli is the earliest person I know of to express this view in a widely read book. At the time, and for the next few hundred years, rulers throughout the western world claimed their power came from divine right. Western monarchies were tied completely to religion, and expressing the idea that common people were tied to power would earn more than a few critics.\n \nB. Machiavelli pointed out how and why to use religion as a tool to gain and maintain political power. As has been pointed out in other comments, appearance matters much more than \"real\" piety. The entire concept of religion as a tool to be used by the powerful was blasphemous to a degree I believe his name remains mud to this day. \n\n200 years before Voltaire; Machiavelli was expressing pre-enlightenment ideas. ",
"Machiavellianism is some seriously depressing and real stuff. I took a class in my senior year of college that focused on him, here is a crash course in Machiavelli.\n\nMachiavallianism is defined as the personal and political teaching which denies the morality to politics, and further claims that manipulation and deceit are often necessary and justified in the acquisition and maintenance of (political) power.\n\nThe Ancient-Modern debate centers around the role that morality and virtue plays in the conduct of political affairs. The original reason for bringing philosophy to politics (Socrates, Plato, etc) was to make politics more just and to help human beings become BETTER people.\n\nThe Modern debate will say that politics has NOTHING to do with morality. You do not have to be a good person to be a good ruler. As a matter of fact, the more \"moral\" you are the more ineffective you will be as a ruler. In your own moral hesitancy as a leader, your enemy will surely run you over.\n\nMachiavelli was deeply suspicious of the Ancient/Modern perspective and what the Christian's called God. He thought, if there is no truth or god, we are left with the here and the now. It's a dangerous, chaotic, violent, and unpredictable place. Machiavelli spoke highly of the separation of politics and religion (church and state). \n\nMachiavelli wrote \"The Prince\" in order to make society run safe and run properly. Also, because he had a problem. His problem was he needed to set a new way of acting and thinking after previously destroying ancient ways of acting and thinking. The context determines what is good and bad. If the ends justify the means and the ends are always changing, then so must the means. In writing \"The Prince\" he wanted to invent someone who could represent the way he thought a leader must act and behave. Because of the constantly changing world, you can't just rely on what you know. There will be a time where you need to be creative and display an act of virtuoso (master of one's craft, game changer). This was \"The Prince\". A prince can be thought of as a virtuoso-an expert at what you do and possess an innate talent to change things, often in times of crisis (FDR and The New Deal). What does something so drastic and life-changing bring someone like FDR? Glory... and well, all princes have glory. \n\nLastly, I thought it was interesting that in the text of \"The Prince\", Machiavelli talks about how, \"The Prince must use the beast with arms\", or the Centaur. The half-man half-beast represents the devil and ruins every conception of what it is like to be human (a unique faculty to reason and talk about justice, virtue, etc). He has literally blurred the line between human and animal. He goes on to suggest we are nothing but mere animals with intelligence. The Centaur is a hooved beast very much so portrayed as Satan. Machiavelli says you have to be BAD, and learn how to be an ANIMAL. Specifically, he mentions two animals: the lion and the fox. \n\nLion-instills fear, backs it up with a certain ferocity. Not afraid to use it's power or intimidation. Lions have no guilt.\n\nFox-quick to act on feet. Very duplicitous and doesn't show it's self (appears good). \n\nAnd in the end, it is not necessary for The Prince to have all of those qualities, rather to appear to. \n\nMachiavellians of our time include Bill Clinton, Lance Armstrong, Charlie Sheen, and Kobe Bryant. \n"
]
}
|
[] |
[] |
[
[],
[
"http://www.gutenberg.org/files/1232/1232-h/1232-h.htm"
],
[],
[],
[],
[],
[
"http://imgur.com/wSmxGcf"
],
[],
[]
] |
||
34mu10
|
if we know jet fuel doesn't melt steel beams then how is 9/11 explained?
|
I don't get it.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/34mu10/eli5_if_we_know_jet_fuel_doesnt_melt_steel_beams/
|
{
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"text": [
"Jet fuel can melt steel beams the guy who made the original theory even said he was talking through his ass. It was a small project ment to fuck with people. It wasn't ment to be taken as fact this widely.",
"1) Combustion temperatures depend, amongst others, on surroundings. The 9/11 crash lead to higher temperatures than the test.\n\n2) Things don't go from completely rigid to molten right away. As temperature heats up, the molecular structure of steel changes and it can rapidly loose it's strength.\n\n3) Fire can and will heavily damage concrete.",
"Let us assume that jet fuel cannot fully melt steel beams: That doesn't mean that the intense heat the fuel applies to the already weakened steel structure can't make the metal malleable and weak. Think of every metal smith you've seen in your life. Usually they aren't dealing with molten steel, they have a steel lump that is extremely hot and is malleable and is almost like dense clay to the hammer. You don't need to completely destroy something to bring down a system relying on it. You just need to weaken it.",
"Ever seen a black smith hammer on a hot piece of steel?\n\nHeat weakens steel. It doesn't have to melt."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
4qoyhe
|
why are we able to predict astronomical events like eclipses and transits down to the minute but we still don't know when or if asteroids like bennu will hit earth?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4qoyhe/eli5_why_are_we_able_to_predict_astronomical/
|
{
"a_id": [
"d4urt8i"
],
"score": [
5
],
"text": [
"A couple reasons:\n\nA) The moon is fairly large and obvious, so it's been observed for a very long time, so we have a *lot* of data to say where it's going to be. It is also less likely to be bothered by small disturbances tugging on it (it don't care if a small rock hits it). It's so large and close, we landed on it and put a laser reflector on it so we could get even more extremely precise measurements. With lots of good data, and very minor disturbances, predictions into the future are easy.\n\nB) Bennu is small, so getting good precise readings at the distances it's at is hard. Predicting where it will be in 20 years is hard if your readings have large variations in them. Also, small disturbances that are harder to predict (small rocks, solar wind). \n\nC) Also, because Bennu doesn't orbit the earth, things like the gravity of other planets may throw (more like tapping) it around more, making it's path just that much harder to predict.\n\nD) We're looking 150+ years in the future, it's going ~ 1.15 (rough orbital radius in AU)*2*3.14 AU every 1.2 years, over 150 years that's about 135 billion kilometers (over 5 light days) away, trying to aim the metaphorical bullet that far ahead is hard. (Yes, the math is very rough, on purpose)"
]
}
|
[] |
[] |
[
[]
] |
||
52jqok
|
the difference between a gatling and a machine gun.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/52jqok/eli5_the_difference_between_a_gatling_and_a/
|
{
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"text": [
"A gatling gun uses multiple barrels, whereas a machine gun uses 1",
"Another distinction is that classic Gatling guns were hand-cranked, while true machine guns (Maxim onwards) are self-powered:the exhaust gases from one round are harnessed to eject that casing and load the next cartridge. Thus when there is a problem with one round the machine gun stops working. In a Gatling gun the gunner would keep cranking full-speed and get some serious jams (ammunition was pretty bad back then so it was pretty common)",
"A Gatling gun has 8 barrels, all loaded. As the operator cranks the hand crank, the barrels rotate. As each barrel gets to the top it is hit by the firing pin, shot, then reloaded all by continuing to crank. A machine gun has one trigger and can be held down to continuously shoot the rounds, powered by the gas released from the first initial shot",
"In modern terms, fully automatic machine guns which use a rotating revolver type of magazine mechanism, or a set of rotating barrels are often referred to as \"gatling guns\", or \"gatling style\", for instance the automatic multibarrel cannon that is used by the vast majority of combat aircraft made in America. This is opposed to automatic machine guns or cannons which only use one barrel and a single bullet at a time receiver, with the bullets feeding in a straight line, not a revolving mechanism"
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
cub4qp
|
How an Aerospike engine really works ?
|
Hi all,
I’m interested in all things rocket, and I found the Aerospike engine very interesting (and super cool looking)
However, I can’t understand what makes it work correctly compared to a normal bell engine :
\-The bell shape is here to redirect the flow (that have a random distribution) so that its coming out on the right direction - > OK
\-when the air is not dense enough relative to what the bell have been designed, the flow coming outside of the bell expands more to reach pressure equilibrium, thus loose thrust at higher altitudes
\- > OK
\-On an aerospike engine, I quote Wikipedia :
“The spike forms one side of a "virtual" bell, with the other side being formed by the outside air—thus the "aerospike".
\- > this, I don’t understand, why, in that case, the thrust isn’t expending on the side like a normal random flow firing in all direction ? the exhaust pressure is still much higher than air….. one side of the exhaust is on the spike make a “half” bell, right, the other, exposed to air, should just go in all directions, like it happens on bell engines ?
If somebody could help me understand the difference, I will appreciate 😊 (i'm not sure if its more Physics or Engineering....)
|
askscience
|
https://www.reddit.com/r/askscience/comments/cub4qp/how_an_aerospike_engine_really_works/
|
{
"a_id": [
"ext8na8"
],
"score": [
18
],
"text": [
" > I don’t understand, why, in that case, the thrust isn’t expending on the side like a normal random flow firing in all direction ? the exhaust pressure is still much higher than air….. one side of the exhaust is on the spike make a “half” bell, right, the other, exposed to air, should just go in all directions, like it happens on bell engines ?\n\nThat's what would happen at normal gas speeds, but the rocket exhaust is supersonic, and supersonic flows are not intuitive. The cold, slow-moving air surrounding the engine literally can't get out of the way of the expanding exhaust stream fast enough, so expansion pressure waves \"bounce off\" the outer surface of the exhaust stream, preventing the jet from expanding.\n\nIn this way, the air around the engine forms a sort of rocket bell, but one that's not solid, and changes its shape to get bigger as the rocket ascends to lower air pressure.\n\n_URL_1_\n\n(from _URL_0_)"
]
}
|
[] |
[] |
[
[
"http://www.aerospaceweb.org/design/aerospike/aerodynamics.shtml",
"http://www.aerospaceweb.org/design/aerospike/figures/fig09.jpg"
]
] |
|
54pbgt
|
what's the difference between debt and bankrupt?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/54pbgt/eli5_whats_the_difference_between_debt_and/
|
{
"a_id": [
"d83tizg",
"d83veuf"
],
"score": [
2,
7
],
"text": [
"Debt is what you owe, but have the means to pay it off.\n\nBankrupt means you have debt, but no means to pay it off.",
"**Debt** just means you owe someone money. You're have to give it back with interest at some point(s) in the future, usually spread out.\n\nBeing **insolvent** means you have debts which you should pay back right now, but are unable to do so because you don't have any income or savings (or too little).\n\n**Bankruptcy** is a legal procedure through which an insolvent person (or company, depending on the jurisdiction) whose financial situation is unlikely to improve anytime soon can untangle the mess and end up debt free after fulfilling certain criteria. These may include selling off assets to make partial repayments and making reduced payments for a certain time from whatever income they have.\n\nThe point of bankruptcy is not only to provide a \"financial reset button\" to the debtor, but also to ensure that the creditors are treated fairly and not indefinitely left uncertain about whether they'll get their money back. It also reduces the incentive to worsen the situation through lies and trickery."
]
}
|
[] |
[] |
[
[],
[]
] |
||
3bs3b9
|
if it is legal to have up to 1oz of weed, how do drug dealers keep from getting arrested since they obviously have more?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3bs3b9/eli5_if_it_is_legal_to_have_up_to_1oz_of_weed_how/
|
{
"a_id": [
"csoyehb",
"csoyls7"
],
"score": [
2,
2
],
"text": [
"This is really a ask a legal question, not a concept question.",
"I assume you are not talking about places like colorado where weed is entirely legal but regulated. \n\nFWIW, they usually DO get arrested. In most places were weed less than one once is decriminalized (not legal, just not a jailable offense - they can still write you a ticket) SELLING weed is usually still entirely illegal, regardless of the amount."
]
}
|
[] |
[] |
[
[],
[]
] |
||
d4a23a
|
How exactly can we tell if other planets have water or water vapor in their atmosphere?
|
I understand the basic principle of measure the dip in light waves when a planet passes between its star and us but I don’t understand how from that information you can determine if there is any form of water.
|
askscience
|
https://www.reddit.com/r/askscience/comments/d4a23a/how_exactly_can_we_tell_if_other_planets_have/
|
{
"a_id": [
"f0ampme"
],
"score": [
14
],
"text": [
"Spectroscopy. We don't just measure the overall decrease in brightness, we also measure it as function of wavelength. Water vapor preferentially absorbs some specific wavelength ranges while it lets others pass through. If we look at these wavelength ranges then the dip is deeper - the planet appears larger because its atmosphere absorbs light there, too, while in other wavelength ranges only the solid or denser part of the planet matters."
]
}
|
[] |
[] |
[
[]
] |
|
4kajqv
|
Book covering the early 1400s to present day
|
I'm looking for a book or series of books basically explaining historical events from the 1400s to present day.
If this isn't the correct sub for this post could you suggest one?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4kajqv/book_covering_the_early_1400s_to_present_day/
|
{
"a_id": [
"d3dwel5"
],
"score": [
2
],
"text": [
"I'm reading and have been quite enjoying John Darwin's *After Tamerlane: The Rise and Fall of Global Empires 1400-2000*."
]
}
|
[] |
[] |
[
[]
] |
|
3aac79
|
How accurate is this style of combat?
|
Recently Ubisoft published a gameplay, in which you can see how christian knights use the sword by taking it by the razor and hitting the other warrior with the handle (I would post the link but I don't know if I'm allowed).
So has that any actual logic or was it actually used in the Middle Ages or is it just plain stupid and put in the game because it looks "cool"?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3aac79/how_accurate_is_this_style_of_combat/
|
{
"a_id": [
"csapla8"
],
"score": [
5
],
"text": [
"There are 15th century German fighting manuals (Hans Tallenhover's *Fechtbuch* or fight book) illustrating and showing captions that depict these kind of strikes in use. They were a technique that was apparently used by European swordsman reasonably often. \n\nI don't know enough about the subject to explain why this particular strike is advantageous. There are a number of users on ask historians that seem to have a deep knowledge of historical european swordfighting and perhaps one of them will produce a more detailed reply."
]
}
|
[] |
[] |
[
[]
] |
|
70fgh5
|
How did the roman military punishment of sleeping outside the camp work?
|
According to wikipedia the romans had as part of a decimation the punishment that a group of soldiers would be forced to sleep outside of the camp. I have a few questions about this.
Did this only apply to groups or also to individual soldiers?
Was it only for one night, or could it be longer than that?
How far away from the camp would they need to be?
Was it dangerous? Were they susceptible to attacks by enemy forces or wild animals. Would they have to provide for their own food?
Was it an exceptional or a regular punishment?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/70fgh5/how_did_the_roman_military_punishment_of_sleeping/
|
{
"a_id": [
"dn443nl"
],
"score": [
9
],
"text": [
"Being forced to sleep outside the camp walls was a part of the decimation punishment, though it had fallen out of use by the time of Crassus and Antony. After a unit had been decimated, the remaining members would be forced to camp outside, and were only given barley or fodder-grade wheat. It’s important to remember that decimation was a “punishment by lottery” and while one person was REALLY punished, it was the whole unit being disciplined. The forced outside camping would span the course of days. \nThe unit discipline would be given after a battle had been fought, or at some point in the relative safety of the encampment. The temporary banishment would not have likely endangered the soldiers, the point was to punish the men, not kill all of them. It wouldn’t do any good to have the entire cohort die.\n\n\nThe rations given were of a lower quality than what a legionnaire would normally be given, and would often cause gastrointestinal distresses. It’s also believed that the barley was viewed as a mark of incompetency, as new recruits were also given that until they demonstrated their ability to their superiors. After the battle of Cannae, some units were issued barley rations for seven years, but this doesn’t seem to be the norm The whole point of the exercise was to humiliate, shame, and further punish the disgraced unit. \n\nBoth of these punishments were very exceptional. Typical discipline involved flogging and fining. Decimation was reserved only for capital offenses.\n\nSources:\n\nThe Roman Soldier, George Ronald Watson; Cornell University Press, 1985\n\nRoman Military Service, Sara Elise Phang; Cambridge University Press, 2008\n\nPolybius, Histories, book 6, chapter 38\n\nTitus Livius, Ab Urbe Condita, book 2, chapter 59\n"
]
}
|
[] |
[] |
[
[]
] |
|
45g40j
|
What is the actual origin of Valentine's day?
|
I have heard that it started as the Roman holiday Lupercalia, but is this true? Also, What is the actual story of Saint Valentine?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/45g40j/what_is_the_actual_origin_of_valentines_day/
|
{
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"czxmhvr",
"czxu9wx"
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"score": [
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4
],
"text": [
"I can't say that I can answer your question in its entirety, but who says that Lupercalia is related to Valentine's Day? As far as I'm aware February 14 was simply the feast day of Saint Valentine, with no implications of a celebration of romantic love until the late Middle Ages. Someone can feel free to correct me if I'm wrong on that one, but that's a pretty big gap to fill to get to Lupercalia. And I can't say I see the connection with Lupercalia. Lupercalia was celebrated on February 15, but that doesn't mean much, there's only so many days in a year, festivals between cultures are bound to roughly line up. Lupercalia's rituals have very little to do with the celebration of romantic love that Valentine's Day is supposed to be in the modern west. I mean I don't see the connection between Valentine's Day and the ritual of slaughtering a dog and some goats at the entrance of the Lupercal, smearing the blood with a knife on the foreheads of two boys who were ritually obliged to laugh as it was done, and then having those two boys run around the city smacking people with thongs cut from the sacrificial goat-hides. I mean, I *guess* there's some sort of possible link there with the fact that Lupercalia is in part a fertility ritual, to ensure bountiful harvests and good offspring, but what that has to do with the romantic love of Valentine's Day I can't say I see. And the fertility ritual aspect of the Lupercalia is hardly the only, or even the most important aspect. The Lupercalia seems to have been primarily a lustration, a ritual associated with purification and aversion of evil, rather than a strict fertility ritual. Coming as it does one month before the start of the archaic new year in March, and one month to the day before the first full moon of the new year (March 15, arguably a more important festival day than the actual old new year) its status as a purifying ritual becomes kind of obvious. I'm not sure what it has to do with Valentine's Day at all",
"No-- Valentine's Day did not get its start as Lupercalia. /u/XenophonTheAthenian has already addressed the (dis)similarities between the two, but connecting the two is further complicated by the relatively late appearance of a romantic tradition associated with the saint. The first recorded, definitive connection between the feast day and springtime, love, etc. appears in Chaucer's *The Parliament of Fowls*. If Valentine's Day was in fact connected to Lupercalia, we would need to explain almost one thousand years of silence. \n\nThe actual story of St. Valentine(s) is a bit more difficult. There are at least two Valentine's associated with February 14th, though more by that name are reported. We have no contemporary records or accounts of the saints; the first *acts* of the two do not appear until the sixth or seventh century. The two accounts share similar structures, and are typical of hagiographical writing in the early medieval period. The first Valentine was reportedly a priest in Rome who gave testimony to his faith before an Emperor Claudius (II). Consigned to house arrest in the home of an aristocrat by the name of Asterius, he proceeded to heal the sight of his host's adopted daughter. When the household converted, Claudius had the priest beheaded. The second Valentine was allegedly the bishop of Terni, who healed the crippled son of a pagan scholar named Crato. When Crato and his household convert, the Roman senators order Valentine clubbed and then beheaded. Valentine of Terni is also mentioned in the seventh century *Hieronymianum martyrologium* and both saints are known to Bede in the eighth. Valentine of Rome also appears in the famous *Legenda aurea* (1255), the story largely following the earlier iteration. Basically, both saints pop up all over the place throughout medieval Europe, but there is nothing to suggest a romantic association that might connect them with a Roman holiday. \n\nThe connections with Lupercalia are largely a product of eighteenth and nineteenth centuries, and though taken for granted well into the twentieth century, it is unlikely that one had anything to do with the other. See:\n\n* Jack Oruch, “St. Valentine, Chaucer, and Spring in February” *Speculum*, Vol. 56, No. 3 (1981)\n\nFor further treatment. It’s a bit dated, but accessible via JSTOR and presents a good case against a Lupercalia connection with St. Valentine. \n"
]
}
|
[] |
[] |
[
[],
[]
] |
|
7ilmcc
|
why do christians celebrate jesus' birthday along with many other pagan traditions?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7ilmcc/eli5_why_do_christians_celebrate_jesus_birthday/
|
{
"a_id": [
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10
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"text": [
"It makes it a lot easier to get a massive amount of people to do something (convert to Christianity) when you don't ask them to change much of what they're doing ( by not making too many changes to their religious practices).",
"The Medieval calendar had a very large number of feast days - close to 30. This were set around the cycle of the farm and the seasons. \n\nSo, for example, around the time that lambs are born, you have a feast, because you have some mutton that died in childbirth and a few more lambs than you wanted to keep, so you have a meat surplus. When the Raspberries start to appear in large numbers, and the farmhands have been bringing it in, you have another feast day with raspberry pies, you make raspberry jam, and so on.\n\nThe pagan holidays in any given area were timed around these appearances for the same reason. When nature gives you a food surplus, you preserve what you can, and feast. This has been the way since prehistoric times in northern climates.\n\nWhen Christianity spread, these same 'natural feasts' were still going to happen. Someone had to eat those dead sheep, you may as well cook a raspberry pie, and so on. So the church naturally took elements of the faith, like important figures and saints, and placed holidays commemorating them around those traditional feasts.\n\nWinter Solstice is by far the darkest of these feats, because it occurs after you've taken stock of what you have for the winter, and decide what you can spare, or if there's going to be hunger this winter. The Baby Jesus naturally symbolized that time best - hope in the darkness, whether it's the hope of salvation after starving to death, the hope of making it through the famine, or the good cheer of knowing you have enough food.\n\nIn today's modern society with greenhouses and refrigerators and international food trade, these holidays make less sense, and most of the old medieval feasts have been forgotten. We've kept a few around as a means to connect with the community. Christmas is one of them. I think you're right to point out that it's not really a Christian holiday, it's a community holiday about hope and family. But I also see absolutely nothing wrong with a Christian seeing that through the lens of Christ."
]
}
|
[] |
[] |
[
[],
[]
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3aaro7
|
Was the fact that companies like Kodak, Hugo Boss, Volkswagen ect were part of the Nazi war effort used against them by their competitors in the post war years?
|
Did rival companies market against these companies, playing on the fact that they had aided the Nazis in the war, however involuntary their contribution was?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3aaro7/was_the_fact_that_companies_like_kodak_hugo_boss/
|
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"Related question: Did any of them get into legal trouble if involved in the death camps, Bayer FEX.",
"VW was famously established as a Nazi initiative. However, this was more than balanced at the end of the war by its recovery through the efforts of [Major Ivan Hirst](_URL_1_), a British engineer from the Royal Electrical and Mechanical Engineers. This started with the use of workshop facilities for the repair of British army vehicles in 1946 but Hirst saw the potential for reviving the no longer functional factory and reestablished production of the beetle. In 1949 years later it went to the German government and was run by new and presumably denazified management. However the link with Hirst and REME was kept so VW's origins were known but it was now considered unlinked to the former regime.\n\nI guess it also helped that early VW was known for producing a basic, affordable car back in those days. This was seen to be vital for the German recovery. Also there was seen to be little high level management continuity into the postwar period (unlike some other German companies). VW did pay compensation later for the use of slave labour though much later.\n\nLater, VW famously made fun of their origins in their co-operation with Top Gear which produced the joke slogan for a high economy car (a VW Polo \"Blue): \"From Berlin to Warsaw with one tank\". VW did, of course, produce [military vehicles during WW2](_URL_5_), but not tanks.\n\nThis may be contrasted with companies like Deutsche Bank and Siemens [where there were stories in the press about their dealings with the Nazis and in the latter case, the use of slave labour](_URL_3_). Whether or not they were planted by rivals is another matter.\n\nSources: \n\nRichter, Ralf [\"HISTORICAL NOTES 4: British Officer and Manager of Volkswagen’s Postwar Recovery\"](_URL_4_) [PDF Warning] Publ: Online by VW AG retrieved 19/6/15\n\nJames, Harold, \"The Nazi Dictatorship and the Deutsche Bank\" Publ: Camb University Press 2004\n\n[Siemens Offers $12 Million to WWII Slave Labor Victims](_URL_2_) Associated Press 24/9/1998 (Retrieved 19/6/15)\n\nAndrews, Edmund [\"Volkswagen to Create $12 Million Fund for Nazi-Era Laborers\"](_URL_0_) published 11/9/98 (retrieved 19/6/15)",
"Whats the story with Kodak?",
"Although the wartime activities of West German industrial firms like Krupp-Thyssen or Volkswagen loom large in collective memory, this memory has not been much fodder for rivals' advertising campaigns. Partly this was because bringing up the war and its associated horrors ran against the grain of postwar European advertising mores. But more importantly, German industry and business leaders conducted an aggressive public relations campaign to disassociate themselves from the Third Reich and portray them as socially responsible members of Western society that were indispensable to rebuild the Western Europe. \n\nAn important aspect of this public relations campaign was to print and distribute tracts that allegedly showed that German industry was not a willing partner in the Third Reich's aggressive war, but also that German industrialists were in some ways victims of the regime. In the immediate postwar years, these efforts were largely focused upon exonerating those business leaders that had been arraigned at Nuremberg, like Alfried Krupp, and to try and forestall and prevent Allied attempts to break up German cartels and industrial interests deemed guilty of collusion with the prior regime. The short pamphlet *Schwerindustrie und Politik* by August Heinrichsbauer was emblematic of these early efforts. this short text, published by a number of Ruhr industrialists and circulated among German public intellectuals, argued that although heavy industry had, like many Germans, made mistakes during the Weimar era, it was not responsible for the rise of Hitler. Heinrichsbauer further contended that the four-year plans and forced labor were foisted upon industry and were antithetical to the deeply-held free market convictions held by many German industrialists. The pamphlet concluded with an appeal for political unity and an assertion that returning German industry to a position of strength would prevent a return to the political chaos of the 1920s. Although it is difficult to gauge the efficacy of public relations efforts like *Schwerindustrie und Politik*, German industrialists arguably did read the Western Allied reluctance to prosecute and break up German industry correctly. Although The Western Allies had already scaled back and limited the number of trials of German businessmen (Flick, Krupp, IG Farben) and only IG Farben would suffer the indignity of being dissolved. this was a far cry from Joint Chiefs of Staff policy directive (JCS 1067) of May 1945 which called for a massive restructuring of German industry. \n\nThis defensive public relations campaign conducted by German industry shifted by 1950 into a more proactive and formalized structure of public relations that cast German as responsible corporate citizens. Organizations like *Deutsches Industrieinstitut* exemplified this refinement of public relations as they had extensive funding from the resurgent German industrial firms. As before, this form of public relations gingerly dealt with the prior regime. This included a wider focus upon influencing American public opinion with translations of the pamphlet *Warum wurde Krupp verurteilt?* which portrayed the Krupp trial as a miscarriage of justice and publishing *Tycoons and Tyrant*, an exculpatory history of German industry. But these efforts of German industry extended beyond a self-defensive apologia, but instead sponsored cultural festivals and trade shows that illustrated West German industry as a vital cornerstone of Western reconstruction. This gelled with German industrialists' self-portrayal as apolitical patriots that had the best interests of their workers at heart. According to them, this lack of an ideological bent made them easy prey for the likes of Hitler, but not for honest partners like Eisenhower. \n\nWithin this context, German firms zealously guarded their disassociation from the Third Reich, making the possibility of a defamation lawsuit quite serious if a rival brought it up in its advertisements. German firms were actually quite willing to use legal action as early as August 1945 when the communist newspaper *Deutsche Volkszeitung* published a report impugning Siemens with constructing gas chambers and crematoria at Auschwitz. Siemens prepared for legal action against the newspaper and complained to the British military authority. The resulting rough treatment of one of Siemens' directors Wolf-Dietrich von Witzleben by British troops, became an early martyr for the industrial public relations effort. Although the rough contours of the wartime record of German industry was relatively easy to uncover, West German industry was able to stonewall serious efforts to investigate company archives. William Manchester's muckraking bestseller *The Arms of Krupp* further heightened West German industry's caution around historians and access to their archives was often quite restricted. The result is that in the early- and mid- Cold War period it was very difficult to accurately define what was German industry's precise role within the Third Reich. The ideological cloud of the Cold War in which the orthodox Marxist-Leninist narrative that industry bore primary responsibility for installing Hitler added a further murkiness to this history. Although there remained a popular connection between postwar West German industrial products and their NSDAP-era predecessors (EG jokes like how many Jews can fit in a VW Beetle; hint: it involves ashtrays), making a precise connection in an advertising campaign was a risky proposition. \n\n*Sources*\n\nDe Grazia, Victoria. *Irresistible Empire America's Advance Through Twentieth-Century Europe*. Cambridge, Mass: Belknap Press of Harvard University Press, 2005. \n\nSwett, Pamela E., S. Jonathan Wiesen, and Jonathan R. Zatlin. *Selling Modernity: Advertising in Twentieth-Century Germany*. Durham: Duke University Press, 2007. \n\nWiesen, S. Jonathan. *West German Industry and the Challenge of the Nazi Past, 1945-1955*. Chapel Hill, NC: University of North Carolina Press, 2001. \n\n_.\"Morality and Memory: Reflections on Business Ethics and National Socialism.\" *The Journal of Holocaust Education* 10, no. 3 (2001): 60-82."
]
}
|
[] |
[] |
[
[],
[
"http://www.nytimes.com/1998/09/11/world/volkswagen-to-create-12-million-fund-for-nazi-era-laborers.html",
"https://en.wikipedia.org/wiki/Ivan_Hirst",
"http://articles.latimes.com/1998/sep/24/news/mn-26067",
"http://www.dailymail.co.uk/news/article-2663635/Revealed-How-Nazis-helped-German-companies-Bosch-Mercedes-Deutsche-Bank-VW-VERY-rich-using-slave-labor.html",
"http://www.volkswagenag.com/content/vwcorp/info_center/en/publications/2013/11/ivan_hirst.bin.html/binarystorageitem/file/VWAG_HN_4_Ivan-Hirst-eng_2013_10_18.pdf",
"https://en.wikipedia.org/wiki/Volkswagen_K%C3%BCbelwagen"
],
[],
[]
] |
|
4z7la0
|
Were people living in Greece by the 10th Millenium BC? If so, would they already be speaking the Greek language?
|
EDIT: And if they weren't speaking Greek by then, what were they speaking?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4z7la0/were_people_living_in_greece_by_the_10th/
|
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"Just double-checking, do you mean 1,000 BC, or 10,000 BC?"
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[] |
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[]
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|
f7ew9k
|
how do direction work in space because north,east,west and south are bonded to earth? how does a spacecraft guide itself in the unending space?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/f7ew9k/eli5_how_do_direction_work_in_space_because/
|
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"Just like on earth n,w,e,s are meaningless without a reference. The same will apply to space. \n\nSince things move in space you will need to use coordinates relative to some set objects. Say certain stars. We havent really begun space exploration to really hammer out a good system but we do use angles and distance that are relative to earth.",
"Directions only work with a reference point (even on earth - the reference point could be the geographic or magnetic poles)\n\nSo in space, a traveller would need reference points - possibly using the center of the galaxy or distant galaxies as reference points. Of course it wouldn't be called N, S, E, W because there are 6 \"cardinal directions\". \n\nFor travel within the solar system, the sun would be a reasonable reference point perhaps along with a few distant stars.",
"Ooh, I know this one. It's called a [gimbal](_URL_2_). The concept is used in [inertial navigation sysyems](_URL_0_). Basically, 3 gimbals provide your 3D reference (xyz) to orient yourself. The gimbals will always be spinning in the exact same orientation in space no matter how a spaceship flips and spins. There's a scene in apollo 13 where they talk about [gimbal lock](_URL_1_), meaning they're losing their ability to orient themselves because one of the gimbals is close to being \"trapped\" or \"caught up\" with another gimbal, losing orientation in that axis. [Here's](_URL_4_) a short video explaining it.\n\nEdit: ~~Imagine two of the gimbals represent the xy-plane and its parallel with the Earth's orbital plane around the sun. You can read the gimbals to tell you if you're pointing \"above\" Earth's plane of orbit or \"below\" Earth's plane of orbit (assuming the North pole points \"up\" for us northern hemisphere dwellers).~~ I'm guessing, I shouldn't do that. \n\nMore science related to gyroscopes and the relevant phenomenon with demonstrations you can see [here](_URL_3_). See also 35:35 for another demo.\n\nEdit: Silly me. Walter Lewin specifically talks about it in this video at 43:50. Watch that.\n\nEdit: I'm an idiot. I'm talking about the gimbals like they're spinning. They're just the rings free to rotate and allow the central gyroscope to spin and maintain its initial position. Don't trust everything anyone says.",
"Currently we map objects in the sky using polar coordinates. Two angles and a distance. \n\nUsually we use Earth as the centre point (in fact the viewers position on earth) and we work out the angle the object is from the centre line of the sky (that we define) and then the angle off the horizon. \n\nThis is declination and right ascension. \n\nIt doesn't make much sense for an interstellar space ship to use earth as the centre point. So we might use the centre of the galaxy. Then define 0 degrees as the line through the sun. \n\nSo the solar system would be at 0°,0°,25kly\n\nChanging direction would also likely use angles. Similar to how boats do it. Change angle a by x° and angle b by y°. \n\nI don't know how actual space craft do it but there it's precedent in fiction with star trek. At the end of an episode the captain might command the helm to set a course 120 mark 43. That's your two angles relative to something (the ship, the galactic plane or something)",
"When away from the earth, stars serve as a suitable reference point. The north star is still in the same direction, even in space, and other stars become easier to use because you are no longer on the surface of a rotating sphere. Essentially, in space every star can be the north star.",
"Spacecraft are able to determine their position and orientation through a combination of on board sensors (like star sensors) and off board trackers (like radar). Beyond that, it is typical to describe their position and velocity as an orbit. These orbits can be described using a few variables that indicate the size, orientation, and direction of the orbit. These are called \"Keplerian Elements.\" \n\nSo, for example if you wanted to convey information about a satellite above the Earth, you wouldn't say \"It's 500Km above the ground, moving 7km/s in the Northwest direction\" but you could say, \"The satellite's orbit has a semimajor axis of 6800km, with an eccentricity of .01, inclination of 23 degrees...\"\n\nOf course, there are other ways of keeping track of and describing these, but that's one of the most basic ways.",
"Play [Kerbal Space Program](_URL_1_). Here is a helpful xkcd to help understand why it will help.\n\n [_URL_2_](_URL_2_) \n\nAlso why you won't be ready for that NASA position. \n\n [_URL_0_](_URL_0_)",
"They would use the very stars in the sky as a way to find where they need to be... they would also use constellations to see where they are for a reference.. maybe even gravitational pull this is an excellent question",
"As an add-on to D1Foley's comment, check out Quill18's \"Kerbal Space Program for Complete Beginners\" series on youtube. He covers this stuff and does a preeeeeetty good job of it.",
"Aerospace engineer here! \n\nThe short answer is basically however you want it to!\n\nThe long answer is something called frames of reference. \n\nA frame of reference, or reference frame, is how you determine your position and orientation relative to another object. On Earth we tend to use down as the direction earth is pulling us, up as the opposite and then north/south/east/west for planar (side to side, forward-back) directions. In space however, there is no absolute frame of reference.\n\n You could be x miles from the earth and y miles from something else. (This also effects velocity but we won't go into that unless someone asks).\n\nSo which reference frame do you use? Whichever one works best. Some times the math is easier if you use earth as a reference frame, sometimes it's easier if you use the sun.",
"I actually work in the space industry, so I feel qualified to answer this. As other commenters have alluded to, there are two parts to this question: reference frame and navigation.\nIn science and engineering, when describing motion you need a base coordinate frame. To start, you need a fixed reference point and direction to base the coordinate frame on. The typical reference is the vernal equinox, which is an imaginary line pointing towards a distant star called Vega. For our purposes, the position of Vega is fixed, so it makes a good reference. From there we can build our axes, but this will depend on the physics involved.\n\nFor a low-earth orbit spacecraft we use the Earth-Centered Inertial frame (ECI), which has an origin at the center of the earth, x axis pointed towards vernal equinox, z-axis pointed through the north pole, and y axis perpendicular to both x and z.\n\nA base reference frame should be \"inertial,\" or non-rotating and non-accelerating, in order to make the physics work out. For an interplanetary spacecraft, the ECI frame is NOT inertial, because it is fixed on the earth which is accelerating around the sun. In this case we define a different frame: sun-centered. In this case the origin is at the center of the sun, X-axis pointed towards vernal equinox, z axis perpendicular to the ecliptic (plane that Earth's orbit makes around the sun), and y axis perpendicular to X and Z.\n\nNow, for navigation: we use devices called Inertial Measuring Units, or IMUs, to constantly measure acceleration and rotation. Think of them as fancy accelerometers and gyroscopes like you have in your phone. If we know where we start, and we keep track of all the accelerations, we can figure out where we end up. The previously described reference frames give us the language to describe this (in terms of X, Y, and Z coordinates). We can improve knowledge of our position with dead reckoning, where we CHECK our distance and speed with radar measurements. If we send a signal to a spacecraft and it takes 20 minutes for that signal to get back to us, then by knowing the speed of light we can say exactly how far it has travelled, which makes the estimate we got from the IMU more accurate.\n\nEDIT: I think forget what I said about Vega. The X axis is defined by the mean vernal equinox, which is when the southern and Northern hemispheres receive the same amount of light (around March 21st). At this point, you can draw a straight line from the sun though the center of the earth and that line will intersect Earth's equator. Because of this, it is by definition perpendicular to the north pole.",
"Earth based directions (North/South/East/West/Up/Down) don't work, so we create a new \"frame of reference\". \n\nA frame of reference is a way of looking at and measuring things. Walking around your neighborhood, you use N/S/E/W, but if you were walking on a huge cruise ship sailing through the ocean, you would use Fore/Aft/Port/Starboard, no matter which direction the boat was pointed. We would say we are moving towards the port side, even if the boat is moving west, so Pot is actually south. We would say we're walking towards the Port side at 1.6 km/hour (1 miles/hour), even if the boat is moving forward through the ocean at 32 km/hour (20 mile/hour). \n\nIn the same way, we can create different frames of reference for outer space. One frame of reference when you are orbiting close to earth, another when you are far from earth and orbiting the Sun, another when getting close to the moon / Mars, etc... \n\nA great and fun way to experience this is to play Kerbal Space Program.",
"Astronautical engineer here.\n\nSpacecraft are equipped with a subsystem called Attitude Determination and Control System.\n\nThis subsystem can contain various tools including Star Trackers, Horizon Sensors, and Sun Sensors for navigation.\n\nThere are lots of stars in space, and a lot of them are so far away that they appear fixed, i.e. they do not seem to move.\n\nA star tracker is basically a camera that scans the space for star patterns. Then it compares the image with the database to estimate its orientation.\n\nSun sensors find the Sun (obviously) and are generally used for solar panel pointing etc. Horizon sensors use infrared to find orientation based on the planet's horizon line.\n\nThis is the navigation part. For control, there are reaction wheels, magnetorquers, reaction control thrusters, and more. RWs spin to generate a moment in the desired axis, so there are mostly 3 of them. Magnetorquers use magnetic field of the planet to change orientation. RTCs are small thrusters that are placed on large spacecraft to perform small correction/orientation maneuvers.",
"Space probes visiting planets, comets, and the like replace \"north\" and \"south\" with stars. They are programmed with star maps in their nav computer, and if they get bumped by a space rock or something they can turn on their camera and watch the distant stars, looking for matches against their database. This is also useful to help ground control know whether the probe followed it's flight-path correctly in normal flight. \n\n\nA probe that REALLY gets smacked will probably tumble too fast to re-align itself, but at that point you are also looking at damage that will prevent it from functioning properly so it's moot.\n\n & #x200B;\n\nSpace probes can also use interial sensors, a bit like your phone does (this is also how the first airplane autopilots worked, btw), and can use the radio signal from Earth to determine its distance and speed. Some more general info here: [_URL_0_](_URL_0_) \n\n & #x200B;\n\nA story about Juno (A Jupiter probe) using star charts: [_URL_1_](_URL_1_) \n\n & #x200B;\n\nIn the future, deep space probes to other systems may use pulsars to navigate.",
"The best part of this question is the number of folks is the aerospace and astronautical field that are willing to chime in.\n\nThanks to all of you, I learnt more than I expected to. Much appreciated.",
"I will explain this using a game of dodge ball. Image you are playing dodge ball, and all you know is where the balls are. If have enough time I am sure you find where and where you are. However, you are the only player try to throw your ball A, to hit other ball B. This a difficult task even when ball B is sitting still. Now image trying to hit ball while a game of dodge ball is being played. Now you need to know where Ball B is going to be in the future. Also, you located other another ball C that being played with. Now you must throw from ball A to hit ball B, all from ball C. In addition you have to account for all of the other balls in the game. The last thing you need to account for is that ball A moves much slower than the rest of the balls. Also, you just barely hit B ball make you don't die on impact. This would be a good to think about travel inside of the galaxy. Traveling Outside of the galaxy would be like throwing to hit another ball that is being used in other game several miles away.\n\nNow unlike dodge ball we know where the stars are, going to be, and we can easily tell stars apart from one another. This means we can tell where we are based off the stars, are going to be, and what time it is.\n\nWhat does this mean is terms of space navigation. You need to know where the other stars are where, how you moving compared to them, how fast you are moving, and what time it is. Also, you may run it a piece of dust ruining all of the math you have before hand.\n\nRight now it is doing lot of math that you do before hand, and then adjust as you get closer. However, for something that can go from any give star to another any other star would have a power computer on the ship do the math every time. You can now see no rushing to leave the solar system.\n\nSo in short its a lot of math get near the star that you hope get you close enough to the star that gravity pulls in the system, and then you steer toward the planet you want go to.",
"Easy, the enemy's gate is \"down\". I'm not a space engineer of any sort, but I can at least talk about the math that's helpful here (linear algebra).\n\nWhen you are walking around, you can talk about how things are *in front/behind* of you, *to the (right/left) side* of you, or *above/below* you. If you want to be clever, you can mix the descriptions too: \"enemy ship at 2 o'clock!\" means something is mostly to your right, but also a bit in front of you.\n\nWhen you're talking to someone else that isn't facing the same direction, you can't just use the forward/right descriptions anymore, so you have to pick something both of you understand. A nice one is to align to the Earth with North/East/South/West. Or, if you know what direction they're facing, you may choose to use their perspective instead (\"turn right on Maple, then turn left on Jefferson...\").\n\nTo give directions, you only need to define the three basic directions \"up\", \"right\", and \"forward\" and go from there. The third can be derived from the first two, so really you just need two of them. Usually you use some sort of reference point(s), maybe a star or a planet or your own spaceship, whatever.\n\nELI25 note: a set of *n* directions for an n-dimensional coordinate space is called a *basis* space, and requires *n* orthogonal vectors. Converting from one basis to another is very easy with linear algebra. With as few as three points that aren't all on the same line (e.g., center of the sun, North Pole of the sun, some other star) you can create a full basis because of the neat property that the cross product of two vectors is always orthogonal to both input vectors.",
"For deep space travel, we would use blinking stars (pulsars).\n\nNot all stars blink, but some of them do. And all the stars that blink, blink slower or faster, but the slow ones always blink slow, and the fast ones always blink fast, but each star that blinks - blinks at its own special speed.\n\nNow if you're on a space ship, you can watch how fast the stars blink and if you're moving closer to it, it will look like it's blinking faster, like when a fire truck is driving towards you and its siren sounds faster. But if you're flying away from it, then it will seem to blink slower, like a fire truck driving away from you and its siren sounds slower, even though the star is still blinking at the same speed. (Doppler effect)\n\nWe know how fast some of the stars are blinking because we've been able to watch them here on Earth, but if we get to fly farther than them, we'll have to find new blinking stars and add them to our map. And if we go even farther than that, we might need to figure out a new way of figuring out where we are.",
"Like all good questions, it depends! \n\n\nIf you are close to the Earth, you use the Earth as reference. You say how far away from the surface and how close to the equator and prime meridian you are. From three measurements that are not in the same direction, you can exactly specify your position. A common tool for this is the ECEF, or Earth Centered Earth Fixed, reference frame. These are coordinates that look at where you are in reference to the Earth as if the Earth never moves. The center is at the center of the earth, the x axis comes out at where the prime meridian meets the equator, the y axis comes out on the equator at 90 longitude and the z axis runs through the poles. This is very handy for looking at satellite positions and figuring out where they are over the Earth.\n\nThat reference isn't that useful if your looking at stuff orbiting the sun. It would look like your position would be constantly changing since the Earth rotates but from your perspective as a satellite you move very little. These objects generally are described using the ICRF, or International Celestial Reference Frame, which is centered at the center of gravitational pull in the solar system. It turns out, as massive as the sun is, it isn't everything in the solar system. The center of mass between Jupiter and the sun is just about on the surface of the sun, rather than deep within it, and Jupiter has by far the biggest mass other than the sun. So we use the point that basically everything orbits in the solar system. Again we use similar references as ECEF to determine a good x-y-z coordinate.\n\nOther star systems and astronomical objects get reference frames as well. We have a reference frame for the Galaxy, for the local galactic cluster, for stars and black holes and everything! Generally you try to find the axis of rotation, like the north and south like for the Earth but on the object, and then something along the equator. Since it's tough to go looking at these objects, we usually pick the line pointing directly at the Earth (or closest to it) and the line perpendicular to both the rotation axis and the Earth line. As long as with three different measurements that aren't in the same direction, you can perfectly specify any point in space",
"A space force is more similar to the navy than the air force. Don't think of a spacecraft like a jet plane; think of it like a submarine - they travel in relation to themselves as the reference plane (down angle, port, etc) and less in relation to nsew coordinates."
]
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"https://en.m.wikipedia.org/wiki/Inertial_navigation_system",
"https://en.m.wikipedia.org/wiki/Gimbal_lock",
"https://en.m.wikipedia.org/wiki/Gimbal",
"https://youtu.be/XPUuF_dECVI?t=23m",
"https://youtu.be/OmCzZ-D8Wdk"
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[],
[
"https://xkcd.com/1244/",
"https://www.kerbalspaceprogram.com/",
"https://xkcd.com/1356/"
],
[],
[],
[],
[],
[],
[],
[
"https://www.scientificamerican.com/article/how-do-space-probes-navig/",
"https://www.npr.org/2016/07/03/484259562/star-trackers-help-juno-find-its-way"
],
[],
[],
[],
[],
[],
[]
] |
||
86qs0l
|
how do people grow pot on tv without getting arrested?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/86qs0l/eli5_how_do_people_grow_pot_on_tv_without_getting/
|
{
"a_id": [
"dw75uff",
"dw760st"
],
"score": [
2,
3
],
"text": [
"No prosecutor will go to court on a charge of posesssion of a controlled substance unless they get their hands on the substance so that they can prove it is something illegal. Without solid proof that it’s pot (and not just something that *looks* like pot), they can’t get a conviction and won’t waste time going for an arrest. ",
"Are you asking about fiction shows or TV as in documentaries? In the case of the documentaries some places it is completely legal to grow. Others, well it’s not hard to hide really if you have the right setup. The hardest part is covering up smell. Some induction fans or blower fans with charcoal filters connected to the exhaust take care of smell very well. Also electrical use gets people caught. Some people wire past their electrical meter so it doesn’t register the use. As far as going on TV with a grow op, that’s an extremely stupid move. Every grower I know that has been caught was caught because they ran their mouth about it. Going on TV is like that but much worse."
]
}
|
[] |
[] |
[
[],
[]
] |
||
29auii
|
Does time flow differently in other galaxies?
|
askscience
|
http://www.reddit.com/r/askscience/comments/29auii/does_time_flow_differently_in_other_galaxies/
|
{
"a_id": [
"cij5i0a"
],
"score": [
5
],
"text": [
"Well, let's first take a look at time itself. What do we know about it? Well, it's relative. Meaning, our perception of time is dependent on several factors, it isn't a single thing that is independent from our understanding of physics. Time is also bounds by these laws.\n\nOne of the major things that affects the rate at which time flows forward is gravity. In short, the greater mass an object has, the faster it will age.\n\nThis can be modeled with 2 humans of the same age. If one goes up into space for an extended period of time, the space human will have experienced a slower time than the one that remained on earth. Keep in mind this difference would be astronomically small.\n\n**And now we get to your question.** In short - yes, but relatively. If the overall mass is different, which it more than likely will be, then yes, the average time will be different. A galaxy with more mass will have a quicker average spacial time. A galaxy with less mass will have a slower average spacial time."
]
}
|
[] |
[] |
[
[]
] |
||
eawexh
|
programing question
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/eawexh/eli5_programing_question/
|
{
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"faybv1o"
],
"score": [
2
],
"text": [
"Yes, you can. The compiled executable and the uncompleted text files have nothing to do with each other. You can change the code while the program is running, and changing the code will not magically alter a running program."
]
}
|
[] |
[] |
[
[]
] |
||
f19240
|
when you turn the ac on, turn the speakers louder or turn on a subwoofer in a car, does fuel economy decrease in order to create more power?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/f19240/eli5_when_you_turn_the_ac_on_turn_the_speakers/
|
{
"a_id": [
"fh2n158",
"fh2r9zc"
],
"score": [
5,
6
],
"text": [
"When you turn A/C on the compressor gets power from one of the engine belts. The compressor turning puts more load on your engine therefore reducing fuel economy. The stereo and subwoofer use electricity which is generated by your alternator. The alternator like the A/C compressor runs off an engine belt as well but the alternator is always running so the only way you could potentially lose fuel economy is if the stereo/subwoofer use enough electrical current to rob power from the engine's ignition system (spark plugs). The A/C will definitely effect fuel economy, the stereo or subwoofer is debatable depending on how much electrical current is provided by the alternator.",
"1 hp is about 750 watts. The alternator is in the ball park of 70 % efficient. Your AC compressor will take 2 or 3 hp mechanically from the engine. Take your electric load, divide by .7 and divide by 750, this is the load your placing on the engine.\nA modern car engine will have a fuel consumption of .4 to .5 pounds of fuel per horsepower per hour. \n\nThis is the extra fuel your burning for accessories.\n\nETA: double checked my numbers, some new cars are getting fuel consumption down into the low .3s. Didn't think they could go that low."
]
}
|
[] |
[] |
[
[],
[]
] |
||
55msv5
|
why are people who run onto football fields so aggressively tackled?
|
I mean, it's not like they have a gun or something, and it seems like regardless, they're always treated like they're a terrorist threat or something. Even when it's obviously for a joke, they end up getting handcuffed and detained, like this - (_URL_0_). Does anyone know how the league ended up taking it so seriously?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/55msv5/eli5_why_are_people_who_run_onto_football_fields/
|
{
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"d8bxbtt",
"d8bxiz1"
],
"score": [
4,
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],
"text": [
"They want to discourage it so that it doesn't become more common.\n\nThey have a game to play (and televise, and sell advertisements for, etc) and don't want it to be frequently interrupted by people running around on the field. As well, if people were to run onto the field while a play were actually going, they could get really hurt. If the punishment were just a slap on the wrist, there'd be a lot of drunk college students willing to just run out there for a laugh, so they make the punishment harsh to try to keep that from happening.",
"You're probably right, a stadium streaker is probably a low terrorist threat, but they've pretty much committed a few crimes, some of which may be felonies.\n\nTrespassing, failure to follow lawful order, resisting/evading arrest, possibly public intoxication and disrupting commerce. \n\nPlus by being aggressive in the detention and arrest, that serves as a deterrent to other people who may be encouraged to streak across the field as well."
]
}
|
[] |
[
"https://twitter.com/i/web/status/782676990927183876"
] |
[
[],
[]
] |
|
3tg8r2
|
could we reproduce the mechanics of what powers the earth's magnetic field, and miniaturize it to protect spaceships from radiation?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3tg8r2/eli5_could_we_reproduce_the_mechanics_of_what/
|
{
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"score": [
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"text": [
"Yes. You just have to figure out how to avoid a strong-ass magnet from interfering with all the equipment.",
"Yes, the earth produce a magnetic field via a rather complicated and not so well understood process but the nice thing about it is that, like any magnetic field you can create it with a coil and some electric current. As said by /u/Lazy_Pea, the main problem with using this to protect spaceship is that you have to protect the ship from the magnetic field too.",
"The answer is...sort of.\n\nWe CAN make a magnetic field powerful enough to replicate the safety provided by Earth's magnetic field. The problem is that the intensity of this field is high enough that it causes some interesting, and negative, effects. Years back I remember reading a paper on this very subject. As an anecdote it brought up the story of a scientist who was present for the changing out of some ridiculously powerful magnets of a particle collider. The old one was sitting off to the side on a cart and he knew that at the focal point in the center the field was stupendously powerful (I want to say something like 1-2 Tesla, but I could be terribly wrong about that). So what did he decide to do? He stuck his head in it! He said it didn't feel that terribly different, except that he started getting a bitter taste in his mouth. He spent a moment trying to figure out what was causing this before realizing that it was the water molecules in his saliva breaking down as they moved between the extreme magnetic field lines. Needless to say, he got his head out of there quickly. While he suffered no ill effects from this, it is generally assumed that any prolonged exposure to this sort of situation would have negative health effects. The reason the paper brought this situation up is that by its calculations, in order to provide the sort of protection we would want in the form of a magnetic field, you would need to expose the astronauts continuously to over four times what the magnet in that story had been rated for.",
"Yes, superconductors could do that. It would provide protection from beta radiation. Alpha is going to be blocked by anything that can keep air it, and gamma isn't magnetic. \n\nThus you would not be completely safe, regardless of field strength.\n\nTo add to that, it simply isn't sensible to use this as radiation protection. The crews water and food suply packed around a storm shelter would be better. But there is still a use for this superconducter magnet.\n\nRemember those beta particles from the sun it stopped? They had momentum. You now have that momentum. It's called a \"mag sail\" and it's a theoretical engine that uses no internal fuel."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
bskk1k
|
how do those cables they string across the road measure your vehicle speed?
|
You know those cables they lay across the road to measure vehicle speed? How do those work? Is it accurate? What is the data used for?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bskk1k/eli5_how_do_those_cables_they_string_across_the/
|
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"text": [
"if I am thinking about the same cables you are thinking about they aren't used to measure speed they're used to count how many cars are going across the road they use it to know how much maintenance or if they need to expand the road to handle more traffic.",
"Usually they are more using it for traffic flow data, before altering a traffic pattern or timing traffic lights, or construction",
"They don't track vehicle speed, the count how many cars pass over them.\n\nThe data is used to figure out how much traffic is going over a particular road to identify traffic patterns, determine light timings, which roads to prioritize repairs, etc",
"They are a known distance apart, so it's simple to calculate your speed based on the time it takes for your wheel to run over the 1st and then the 2nd cable.\n\nHowever their primary purpose is for traffic counting."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
4dr934
|
how do people not feel effects from thc and other substances if they're still present in our systems for up to days/weeks/months enough to show up on drug tests?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4dr934/eli5_how_do_people_not_feel_effects_from_thc_and/
|
{
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"text": [
"Two reasons: First, much of the substance is excreted out of your body. They are testing for what small amounts are left over. The concentrations in your body are very very small, and not enough to make you feel any effects, but can still be detected.\n\nSecond, depending on the drug, they are not always testing directly for that drug, but its byproducts. You're body will break down the chemicals in the drug, but the byproducts of that process can hang out in your system for a long time.",
"Drug tests that look for weed don't actually look for thc, they look for the metabolites that are left over in your system as the result of your body breaking down thc. The reason it takes so long for your body to rid itself of thc metabolites is because thc is easily absorbed by body fat.",
"TCH proper is not still in your body.\n\nThe unique chemicals TCH breaks down into are, and that is what a tests can detect."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
bhd2dr
|
why is scrotal skin so different from other skin?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bhd2dr/eli5_why_is_scrotal_skin_so_different_from_other/
|
{
"a_id": [
"elrv9hs"
],
"score": [
3
],
"text": [
"Because it has a very particular job that other skin doesn't.\n\nYour testicles have to be kept at a certain temperature, one that's lower than the rest of your body. So your scrotum needs to be able to adapt to temperature and then respond by raising or lowering the testicles, becoming thicker, or thinner and shrinking or expanding.\n\nSo basically because your balls need to stay cool/warm."
]
}
|
[] |
[] |
[
[]
] |
|
b357cf
|
why is there seemingly only 5000 species of mammals on earth yet seemingly endless minute variations in insects/birds/reptiles etc?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/b357cf/eli5_why_is_there_seemingly_only_5000_species_of/
|
{
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"text": [
"Smaller reproduction times and lifespans means you can have more generations and a higher rate of mutation. ",
"Mammals are the most recent biological class to come along. We haven't had the time to develop as many mutations which might be beneficial enough to branch off into nearly as many variants",
"Bird and reptile species aren't that much more numerous than mammals at around 10,000 each compared to insects at up to a million.\n\nReasons that there are so many more insect than vertebrate species are their size and complexity. Vertebrates are for larger and more complex and need far more space to live. They can also move around much more so they can choose to live in an area that is more suitable for them and allows for the increased necessities that come with greater complexity. This means there is less separation of groups that might diverge from one another to form different species. Insects on the other hand can travel far less and must instead become very specialized to the local environment they live in causing greater diversity in species.",
"* TL;DR: Insects had an ecological and evolutive edge over other animals. Their ability to fly let them invade the land before any other animal could. They had lots of resources available, letting them specialise, thus generating several groups and species.\n\n---\n\nAlthough the other explanations offer some valid points, they don't quite hit the nail. There are roughly [5300 living mammal species](_URL_7_), [18k bird species](_URL_2_), and [10k reptile species](_URL_10_) (without considering birds). On the other hand [insects are estimated to be around 5.5M](_URL_6_). Before diving deeper into the reasons why there's way more insect species than all other animal groups combined, I would like to point out that the concept of species isn't equally defined for each living group. So, the parameters used to define an insect species are different to those used to define a mammal species to those used to define a plant or bacterial species. I'll focus on comparing insects against mammals.\n\n#1. Insects are old, mammals are young\n\nFirst we need to have some historical context. When did insects and mammals appear? According to the available fossil record, insects appeared around the [Devonian period](_URL_1_), around 419.2 - 358.9 millions years ago (Mya). Mammals appeared on the [Late Triassic](_URL_0_), 251.2 - 201.3 Mya. That means that insects have been existing roughly 200 million years more than mammals; almost twice as much!\n\nIf we assume new species appear at the same rate among both groups, that difference would account by itself as the main reason why there's more insect species than mammal species. But, there's only about [4 000 species of fish](_URL_8_). If time was the only factor, we should have more fish species than insect species. **Time itself can't explain such diversity**.\n\n#2. Insects reproduce faster than mammals\n\nThe next factor we should consider is that insects reproduce more frequently than mammals. Most insects reach sexual maturity within weeks and in a few months they have already reproduced at least once. On the other hand, mammals take more time to reach sexual maturity, from a few months to some years.\n\nLet's try a hypothesis! Let's assume insects and mammals appeared at the same time, they have the same rate at which new species appear but they differ in generation time: Insects have more generations per year than mammals. In this case we would expect insects to have an edge and after a while they would end up with more species than mammals. To spice things up, let's bring a third group into the race: Plankton.\n\nThese unicellular organisms reproduce even faster than insects. They take a few hours to some day to reproduce. If our hypothesis is true, we should have more plankton species. But that's not the case. [An estimate made in 1991](_URL_4_) said there were roughly 4 000 species of plankton in the ocean. Even if we double that number to 8 000 to compensate for land plankton, we would be far from the estimated 5.5 million species of insects. Just like it happened before, **generation time can't explain the tremendous richness of insect species**.\n\n#3. Adaptive radiation\n\nLife began in the ocean. For millions and millions of years only water bodies could sustain life. After millions of years the first organisms were able to inhabit land but they weren't animals, they were fungi and plants. For even more and more years the land was untouched by animals, fungi and plants could thrive with ease without any predators. That's when insects invaded. Winged insects were the first animal group to successfully inhabit the land, during the [Carboniferous](_URL_5_) (356-299 Mya).\n\nWhen insects arrived to the land it was paradise for them: The abundance of fungi and plants meant they have plenty of food to consume and the absence of other animals meant they didn't have any competition. Thus, they were able to thrive. Here's where the major evolutive event on the insect group happened.\n\nEvery once in a while the conditions align for a particular group to thrive exponentially. Having plenty of food and not having any predators or competition were the conditions that let insects to develop lots of species. When there's lots of resources you can give yourself the luxury to be picky. Insects began to specialise. Some only ate fungi. Some only ate leaves. Some only ate leaves of a few species of plants. Some only ate the seeds of a singular plant species. Some began to consume other insects. Some only consumed the insects that only ate seeds. Some ate a little bit of everything. Those \"available resource slots\" are known as \"niches\". When there's lots of available niche slots, [species radiation](_URL_3_) happens.\n\nInsects had the land for themselves for a long time. They have the time to develop several groups with several species. They spread all over the world in fantastic fashion. The ability to fly played an important role in this domination of land. Being able to fly made them harder to consume by the predators that eventually appeared on land, let them move around easily from resource patch to resource patch and so on.\n\n4. What about mammals?\n\nWhen mammals appeared most ecological niches were \"already taken\". Reptiles and other animal groups already were consuming other animals all over the place, all types of plants, a little bit of both, etc. When they came into existence land and sea were already taken. It wasn't until the [Cretaceous-Paleogene extinction](_URL_9_) that mammals had the chance to occupy the niches left behind by the dominant group at the time: The dinosaurs.\n\nCompared to the adaptive radiation of insects when they invaded land, the mammal radiation when dinosaurs disappeared isn't as successful.\n\n#Conclusion\n\nSometimes the conditions are perfect for a group to thrive and generate lots of species. For insects it was the invasion of land when no other animal group have done it what enabled them to diversify tremendously. On the other hand, animals were only able to diversify a little after dinosaurs disappeared but they didn't have as much liberty as insects had when their radiation even happened."
]
}
|
[] |
[] |
[
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Late_Triassic",
"https://en.wikipedia.org/wiki/Devonian",
"https://www.amnh.org/about-the-museum/press-center/new-study-doubles-the-estimate-of-bird-species-in-the-world",
"https://en.wikipedia.org/wiki/Adaptive_radiation",
"https://www.researchgate.net/publication/30979635_Marine_phytoplankton_How_many_species_in_the_world_ocean",
"https://en.wikipedia.org/wiki/Carboniferous",
"https://www.annualreviews.org/doi/abs/10.1146/annurev-ento-020117-043348?journalCode=ento",
"https://academic.oup.com/jmammal/article/99/1/1/4834091",
"https://www.nature.com/articles/srep00561/figures/1",
"https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event",
"https://phys.org/news/2014-08-reptile-database-surpasses-species.html"
]
] |
||
1eb4lg
|
WWII - How much did the Axis powers know about the Allied invasion plans on D-Day-1?
|
I know dis-information was spread but were they expecting the invasion on 6 June 1944?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1eb4lg/wwii_how_much_did_the_axis_powers_know_about_the/
|
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"It depends. Rommel is on record claiming that the Allies would come at high tide to minimize casualties crossing the (narrower) beach. This ruled out the 6th of June since it was generally acknowledged that the attack would commence at first light, and first light at June 6th had the low tide. That would mean the assaulting troops would have to cross a wide beach under fire, which didn't mesh well with the observed Allied straategy of minimizing casualties. German defenses were accordingly designed around an attack at high tide (the beach obstacles you can see in Saving Private Ryan etc. would have been underwater had the attack happened at high tide). \n\nFurthermore, German weather experts predicted poor weather for most of early June. Allied weather experts did much the same, except for a small break on June 6th, which Eisenhower gambled on. \n\nHowever, German radio intelligence had intercepted allied transmissions to the French resistance, which included codewords to start actions in support of an invasion in the next 24 hours. The Germans knew what this meant and passed it on. The officers in charge of the actual defenses responded that the Allies surely won't announce the invasion via the BBC and did not act. Even when the airborne invasion started, many still thought it was a diversion or a raid. \n\nSo no, they weren't really expecting it except in the most general term that they knew the invasion would come during 1944. "
]
}
|
[] |
[] |
[
[]
] |
|
2gy4qj
|
why can't you cut all the wires in a bomb to prevent it from detonating?
|
I mean, in theory, if you cut all the wires at once you stop the electric flow to signal the detonation. Why don't they show it like that in the movies? Why would this not be possible?
EDIT: Thank you for all the great replies. I would have not imagined this question to become so popular. It's still the top question on the front page of /r/explainlikeimfive. Yesterday, it was on the front page of reddit. I'd like you guys to check out other questions and answer them too. I feel bad for other simpletons like me that have their questions gone unanswered because of the popularity of this question. Please check them out :)
Thank you so much for contributing my to my learning experience! I hope that everyone that participated in this thread learned something. Let's do the same for other questions.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2gy4qj/eli5_why_cant_you_cut_all_the_wires_in_a_bomb_to/
|
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"I can very easily rig up a dummy bomb for you that would go \\*pop\\* if you cut the wrong wire.\n\nSometimes, it is the presence of electricity that prevents a circuit from triggering rather than a lack of it.\n\n",
"Perhaps in practice to a limited degree, but used more as a plot tension in movies and TV, the bomb maker would have installed booby-trap wiring that, if cut, would instantly set off the bomb. This would be done in order to confuse and confound any person attempting to disarm said device.\n\nThe ridiculous part of these \"defusing\" plot devices is when the \"bomb expert\" is instructing another person how to defuse the device over a phone by telling them which color wire to cut. There is no standardized color coding for illicit explosives, and if there was one it certainly wouldn't be followed by a person attempting to install anti-defusing systems into the device. ",
"All these answers are wrong. Here's what an EOD tech said on Reddit a while back, paraphrased from memory:\n\nDo you know the difference between car brakes and 18 wheeler brakes? car brakes have brake fluid, so when you step on the pedal you are physically forcing the brake to stop the tire. As long as you don't press thee brake, no stopping, but if you cut the brake line the fluid get's out and you *can't* stop. 18 wheelers use \"air brakes\", where the brake is **always trying to close** and is being stopped by the air brake system. When a trucker hits the pedal, he is allowing that system to fail, causing the brake to close. If a truck's brake line goes, it's brakes are locked-on. \n\nNow, bomb's are always trying to explode. That's their design. The only thing that keeps the bomb from exploding is the system around it, and the timer/cellphone/trigger device *will not turn off* until it's trigger is activated. The system is keeping the bomb *from* detonating. So if you cut some wires and brake the system- boom. You've just destroyed the piece that was keeping it stable, like cutting the air brakes. That's the ELI5 version.\n\nTL;DR- the trigger is actually stopping the bomb from blowing up. If it fails, boom.",
"All depends on the design. If the bomb is \"looking for\" 12V, then cutting wires would be fine.\n\nIf, however, 12V is \"preventing\" the bomb from blowing (which would be ideal in such a case), then cutting wires would be a bad idea.",
"The thing that always confuses me is that in movies, there is always a bomb diffuser guy trying to dismantle the bomb. And he is always looking at the wires and thinking \"was it the red wire or the black wire?\"\n\nI always wondered why a bomb builder would stick to bomb making conventions...or even use colored wires at all.\n\nWhy not use all black wires and just label them as you are building, then remove the labels when you are done?",
"The simplest type of bomb, like a grenade or a Molotov cocktail, has no wires - you light the fuse and throw it. \n\nA less primitive bomb has a timing device attached to a triggering device that sets off the explosive charge and this one can be defused simply by cutting the wires.\n\nA more sophisticated bomb will use a series of relays to connect the timer to the triggering device, one of which will be a *normally-**closed** relay, one that requires power to keep the circuit open rather than closed. Cutting the wires to this particular relay will cause the relay to close and allow power to go directly to the triggering device. (As bigblueoni pointed out, that's how fail-safe air brakes on big trucks work - the air pressure is not what makes the brakes go on, it's what keeps the brakes from being applied. If the brake system \"fails\", it fails to keep the brakes from being applied.)\n\nIf you know a little bit about electrical circuits it's easy enough to identify which wires are the ones going to the triggering device and cut those wires. \n\nBut if you're the bomb-maker and have gone to the trouble of making a bomb designed to go off if it's tampered with it's easy enough to install multiple circuits, dummy circuits, hidden circuits, motion-triggered circuits connected to flaps or boxes within the bomb package, etc., which makes it impossible to tell which wires do what. It's hard to tell if you're actually cutting all the wires or the important wires or the wires that are keeping the bomb from exploding.\n\nFortunately, most of these complicated sorts of bombs only exist in the movies.",
"Wouldn't just pulling the detonator out of the C4 or whatever always be a viable solution, assuming that it's accessible?",
"Would removing detonators or cutting detonator wires do the trick? Though I imagine many ied bomb casings may not grant access to detonators.",
"The IEDs that you hear about in the Middle East that explode on Humvees typically use a circuit that is always on until the weight of an overhead passing military vehicle's tires cut off the circuit which triggers the explosion. This is why MRAPS have giant rake attachments with wheels that drive way in front of the vehicle.",
"All modern bombs, that you see on TV mostly and everywhere else, have a microprocessor in them. This is basically a very basic and simple computer that manages the device, from remote triggering, to the timer, turning it on or off, detonation, anything you can think of. \nAll these microprocessor chips can either send out or receive commands, at the same time. So the chip sends information to the display, so it can show the countdown and also sends out a detonation command when the timer reaches zero. \nBut the other thing it can do, is \"listen\" to other parts of the bomb, which send feedback to the chip that everything is as it should be. This is why there are dummy wires in the bomb. Their only purpose is to tell the chip, that the device is not being tampered with. If one of these is cut tho, the microprocessor understands this as someone trying to disarm the bomb and is programmed to override the countdown timer, basically ignore it and immediately issue the blow up command and this is why you can't cut all of them at once or just random ones. They would be called control wires in this case. ",
"Because there are 2 sorts of switches, Normally Open, and Normally Closed. The electrical current is holding the Normally Closed switch open. Interrupt the current and the switch slams shut. Click, Boom. Then factor in capacitors, other relay switches, mechanical switches, it gets a little complicated. ",
"EOD Tech here. I wanted to chime in because the top replies are mostly wrong.\n\nFirst of all, to answer your question simply:\n\n - Some \"firing circuits\", that is, the circuit in an electrically initiated explosive device(i.e., it contains a battery and electric detonator) **can be interrupted in literally any fashion to \"render safe\" the device.** Firing circuits can be as complex or as simple as **any other type of circuit**. Think of a detonator as a lightbulb, and the device \"initiator\" as a switch(this can be anything, a cellphone, a pressure plate, a suicide switch, whatever). The only other thing you need to complete the circuit is a power source(a battery, for example) In this type of circuit, **you can cut any wire** and the device **cannot work**. There's still explosives present, and there's still measures that need to be taken for that, and you still have to get rid of it, but **the device will no longer function as designed**. It's simple electronics. For the record, this type of device is very common.\n\n - Now, obviously, someone with a lot of electrical know how can design a much better firing circuit. This is where the skill set of the EOD tech comes into play. It's important to diagnose a circuit completely before taking any action. The most straight forward type of circuit **that cannot simply be interrupted at any point in the circuit** is called a **collapsing circuit**. There are several ways to build a collapsing circuit, including using relays, semi-conductors, and various other electrical engineering techniques. I won't explain this further. Suffice to say it's possible to booby trap a circuit so that if a wire is cut, the device will function. This is a much rarer type of device, but one that EOD tech's still train to handle\n\n - Then, as another commenter has mentioned, there are lots and lots of types of explosive devices that don't use electronics of any kind, and therefore there are no wires to cut and other steps have to be taken depending on the type of device.\n\n**TL;DR**: There is a lot more than one type of explosive device. Sometimes, any wire can be cut. Sometimes it can't. Sometimes there are no wires.\n\n**addendum**: Generally speaking, an EOD tech will exhaust all other possible measures before physically interacting with a device in any way. We have a lot of tools and techniques at our disposal, and if possible, we won't go anywhere near a device until it's as safe as we can possibly make it remotely. \n\nedit: speeling.\n\neditedit: Thank you very much for supporting reddit by providing me with gold. It's pretty awesome of you.",
"I'm an EOD tech and a perpetual lurker. I was so taken back by how incorrect the top comment was that I created an account to respond. Bigblueoni's explanation is completely wrong when applied to the majority of IEDs. I'm not going to explain how \"bombs\" work, but to respond to OP, there are very complex electrical circuits out there. There are also very simple ones. A smart bomb maker can make an IED that goes \"boom\" when you cut/touch/move/etc. certain components or wires. That's the ELI5 explanation. \n\nTo be absolutely clear, bigblueoni is completely wrong. Whoever gave him gold should ask for a fucking refund. Bombs are NOT always trying to explode, that is not a typical design. I don't feel comfortable saying anything more, but I don't want everyone to have this ludicrous idea about how basic electrical circuits work. ",
"I love how the movie stereotype of bombs still persists.... nobody makes bombs to be \"hard to defuse\", they don't make them to beep and there's no countdown timer to look at pretty numbers while it beeps.\n\nThe overwhelming majority of bombs are made to explode on queue, they're pumped out en mass, not masterworks expecting a movie demolitions expert to try and defuse them.\n\nA staggering amount of explosives are going to be a case of \"pull the detonator/blasting cap out of the explosive material\", and that's assuming you even WANT TO. \n\nThere's no reason to defuse a bomb unless it's somewhere that detonating it is going to cause problems... just slap a line of something on there, drive 200m and boom!",
"I don't know anything about bombs, but I have done some work on alarm systems that are setup with a fail safe in mind. If the power source goes out, a relay trips and complets an activation circuit to shut something down, so the relay needs power all the time. I am assuming it's the same situation with a bomb. You must find the wire that is being switched and disconnect it first. If you mistakenly cut a wire that controls power for the relay, the device would activate assuming it's using a different source for power. ",
"What I don't get is why they colour the wires. Why make the bomb easier to defuse?",
"The answer is as simple as wrong it normally closed instead of normally open.",
"The truck air break analogy is good but not really explaining how it works.. A bomb is the actual explosive, the detonator is what makes the bomb explode. And a detonator is an electrical circuit. Like a flashlight with a battery it has a negative and a positive end and when you connect the two to a light bulb it turns on by sending electrical current from the battery to the bulb. A bomb works the same way, when all the wires are separated and insulated the bomb is fine because the electrical circuit is not complete. But when a trigger is activated it completes the circuit sending an electrical signal to the detonator therefor making the bomb explode. So if you were to cut all the wires at ones you would be completing the circuit because your cutters are metal and would (at a moment) touch all wires at once. ",
"most EOD techs use not wire cutters as their primary disarming tool, but a Barrette .50 or a shotgun, this process is called energetic disruption, and it works because it explodes the device without detonating it, rendering it harmless as the explosive agent is sent fucking everywhere.",
"Wtf do they do then when they find a powerful bomb? Ie, what would have happened if someone found Tim Mcveigh's Oklahoma city bomb? You can't just have a robot move and self contain that kind of explosion. I'm just using that bomb as a reference. Think a powerful bomb that can take down a building, and have enough electronics to confuse someone.",
"If the circuit consists of a battery connected to a blasting cap through a switch, then cutting a wire to the switch, battery or blasting cap will disable it.\n\nIn theory, this basic circuitry could be embedded inside the bomb so it is not accessible without cutting some external wires. The inside part could contain circuitry that triggers the bomb if any external wires are cut. The external wires could be disguised to look like a battery/switch/detonator. This would be a more difficult device to build. I'd be surprised if this happens in practice.",
"It all depends on the design of the particular bomb. Some are very rudimentary and cutting pretty much any wire will make it inoperable. Others are designed with traps where opening an access panel to get to wires will cause detonation. There is no one answer to this question. ",
"The makers of bombs don't want them to be easily defused so they booby trap the trigger. For instance a secondary triggering device might be a percussion cap with a spring loaded firing pin set to hit it once a relay loses power. The wiring system can be quite complex, too complex to understand at a glance. Think a complicated procedure in some programming language (some early computers were programmed with jumper wires in a switchboard like module...) it takes time to understand how it works. Meanwhile the clock is ticking.",
"I'm very sorry but this analogies are wrong, and are not explaining what is actually happening.\n\nThe circuit board is sending a digital 1 output, 1 means the switch of your light bulb is \"ON\", this switch is going trough a \"NOT\" gate, what this gate does is to take the 1 or \"ON\" and turn it into a 0, or \"OFF\", all the time, once the time reaches 0 the switch changes to \"OFF\" and the not gate triggers a 1 or \"ON\".\n\nIf during this time you cut the cable that is sending the \"OFF\" signal you will automatically call the \"ON\" signal and the bomb's trigger.",
"Currently cunducting route clearance in Afghanistan and we have come across many IED's since we've been here. Most of the bombs we come across are simple one switch circuits which usually consist of one pressure plate. You step on or drive over one of these and it completes the circuit between the power source and the blasting cap. Once one of these potential threats are found, usually with ground penetrating radar, we do the ol \"I hope this shit don't explode\" dig untill we find all the components and identify their purpose. If it's the usual simple switch initiated IED, simply cut any of the wires and it will render the bomb inoperable. Then WE blow it up with C4. If the device is more technically advanced with possible anti tamper components and we are not confident on exactly how it works, we send the robot up with some C4, identify the main charge, and blow it up. \n\nIf a bomb was somewhere where you couldn't just blow it up with C4 say an airport, i'd say cut the det cord leading to the blasting cap. Or if it's an electrical system, cut the two wires leading to the blasting cap. This should rule out any anti tamper circuits. Some people here like to think there's some hidden power source waiting to close a circuit once a wire is cut and will cause it to detonate. Well guess where the power from that second battery is going? Cut the wires closest to the blasting cap and only if you can visually see the wires directly connected to it. This is all assuming the bomb is detonated by a blasting/firing cap, which most explosives are.",
"Relevant question on the Electrical Engineering Stack Exchange site: \n[Why would clipping a wire cause a bomb to explode?](_URL_0_)",
"Booby trapping booby traps is the worst problem. I read about demolition guy in Vietnam. He was going to detonate a booby trap. Safest way to disarm, right? So he looked around and the only cover was a tombstone about 25 yards away. So he took cover there and detonated the device-- only to detonate another booby trap behind the tombstone, killing him. A tough job indeed...",
"You have to understand logic gates, AND, OR, NAND, NOR, XAND, XOR etc etc, and how they use voltage and current to activate relays and switches. Hitting something with a stick, unfortunately, doesn't always work.",
"no one cuts wires to disarm a bomb. They blow it up either in-place or if they determine that they can safely move it they will move it away from structures and blow it up there. Because there is no standard way to build a bomb and know way of knowing how each one was put together. For example, every US airport has a designated area where they will take a bomb to blow up if the TSA or cops find one.",
"You don't know whether:\n\nIf the timer/remote is preventing the detonation, and disconnecting it (or the timer running out) will cause it to go off, or,\n\nIf the timer/remote will trigger the charge, in which case it would be safe to cut. \n\n50/50 aint good odds, and this is a pretty simplistic cartoon style bomb.",
"Good question. I honestly have no actual idea, but I would say that there is a certain wire *preventing* the explosion from happening, so if you cut the wrong one (that one) you'd initiate the explosion. And maybe what the detonator does is cut off power to the wire that prevents the explosion. One hell of a theory, and probably wrong, but it makes sense to me :P",
"Just clear the area, blow it yourself with your own charge, and hope it goes low order.",
"A very simple thing to point out is that there are circuits which can trigger due to lack of signal (logical 0), so cutting a wire would actually trigger the bomb.",
"Former EOD student who got kicked out then went and took a circuits class. There's a lot of ways you can configure a bomb to explode, with no one way to render them safe. With chips they way they are these days, crazy shit can be made to initiate the explosion. Cutting wires is stupid, use a robot.",
"is there a compilation out there of movies that actually have thi scene in it?\n\nIt seems like its spoofed more than its used.",
"I think some bombs are wired so that the electric current is the thing **stopping** it from detonating. So when the electric current is lost, boom",
" a bomb with actual wires is a bomb using a computer controller or circuit to trigger detonation. The trick is not to cut the wires but rather to separate the controller from the detonation method (det cord, caps etc). Once the controller can no longer interact with these things the bomb can not be triggered. \n",
"More than anything how do you know you are cutting \"ALL\" the wires? You might just be cutting all the obvious wires(AKA \"Darwin wires\").",
"You can't just cut all the wires in the situation you're talking about.\n\nIf the device is booby trapped to go off if the wrong wire is cut, you can't just cut them all really fast. You aren't faster than electricity.\n\nSay you had two light switches and that went to the same light. When they both down the light is off and when they're both up the light is off but when one is up and the other is down, the light is on. If you flick both lights switch up really fast, the light isn't just going to not go on. One of the light switches is going to complete the circuit a fraction of a second faster and the light will go on \nbriefly.\n\nIt's the same with your hypothetical bomb. You can't \"beat\" a circuit from completely.",
"I feel like people are getting way into how bombs work and aren't answering your question. Bombs can be designed to be tamper proof, so that if you cut \"the wrong wire\" (or **any** wire in a really good bomb) the bomb will explode. \n\nYour question is, why can't you just cut all the wires at once? In theory, this would work. However, electricity travels at the speed of light, and micro-controllers operate at frequencies of over 100,000,000 operations per second. The reason you can't cut all wires is that it simply can't be done fast enough. Based on how the circuit is designed, you could have less than a millisecond after cutting the \"wrong\" wire before the bomb explodes. If you could cut all wires in under a millisecond, in theory you could do it. But no human, (or machine, yet) can achieve this.",
"Maybe there is a relay holding the charge from detonating? If you cut the wire going to the relay, it will let go and BOOM\n\nIf its a PNP transistor, Keeping it at \"high\" level ( with voltage on the gate) will keep it off. Disable it and goes BOOM. \n\nIf its a PNP, then that wire could be pulling it low. Cut it, it will go High and BOOM.\n\nIf its a complicated circuit, and you cut some wire, it could DE-stabilize the circuit, making some voltages increase or decrease, thus activating it and goes BOOM.\n\nSometimes they add extra wires, and if you cut the wrong one, it activates the signal on purpose and goes BOOM.\n\nBy cutting more than 1 wire at the same time, you can short circuit both wires and goes BOOM.\n\nWhen talking about Clocks, there is such a thing as set and re-set. If you cut the right one, the clock goes to max state, such as 99:99, cut the wrong one, and its a shortcut to 00:00 and goes BOOM.\n\nAnd most of the time, if a good bomb maker is involved, they will encase the whole thing in plastic, making it impossible for you to know what wires goes where and does what. all you see is wires going to a black plastic block.\n\nEven encasing the bomb is not safe. If the signal is made to refresh every certain amount of time, by radio control, by blocking the signal it will prevent it from refreshing. Since the bomb cannot hear the signal of \"its ok keep counting\" it will not re-set and go BOOM.",
"What if electricity going through one of those wires is what is keeping the bomb from exploding?",
"Tiny question here: why doesn't anybody gently pull the blasting caps out of a brick of plastic explosive and throw the explosive like a baseball to some safe-ish area? ....assuming the explosive is C4, you can run it over with a truck, drop it from a plane, set it on fire and/or shoot at it with rifles and it won't explode, so why isn't this a good idea? The blasting caps will explode, but we're talking firecrackers, not half the building missing.\n\nI can think of a couple ways to still make it explode, but they're quite a bit more advanced and never done in movies.",
"Simplest answer is that it could be designed to detonate when an electrical flow is stopped.",
"Some newer devices using modern electronics have a LOT of wires. It became something of a subfield in IED making to have devices with incredibly complex circuits. You could certainly try, but there's a threshold where the number of wires that you would have to cut simultaneously is technically possibly but logistically just not going to happen. It's also interesting to note that you can design bombs that start with an electrical signal to activate something else, like another, smaller circuit, that is designed to detonate the bomb if that signal is shut off. I think the term that best describes these are \"fail deadlies\", meaning that rather than just shutting down if some sort of error occurs, it instead self destructs. There are also other really pesky things that aren't as common as they once were, like anti-handling devices. Those are basically components designed to activate the bomb if something is moved or touched the wrong way. A could example of this might be that there is a shell around the actual explosive material, and a light sensor on the inside. The light sensor doesn't do anything until the bomb is activated, at which point opening it up to expose the actual mechanisms you need to disable or tamper with to stop the bomb, light will activate it and make the bomb explode. There are lots of similar devices that get more and more complex as you go on, and it basically ends up making it very dangerous to just try to cut them all at once. But hey. I'm mostly an armchair expert. ",
"Relays.\n\nRelays are electric switches, they either make or break connections. Some relays are open (disconnected) when power is off and closed (connected) when power is on and some are the reverse.\n\nSo, if you want a switch that closes a circuit (blows up the bomb) when power is cut, you use a power off relay. \n\nThe problem is with cutting all the wires, you don't know if they have a failsafe, power off relay in there.",
"Terrorist 101: Explosives\n\nBasic explosives - there are explosives and there are blasting caps. Most explosives are made to be relatively safe and inert, so that they don't go BOOM accidentally. Some explosives are sensitive, whereas things like C4 (like clay or play-dough) and diesel-fertilizer mixes are relatively inert, you can hammer them and they won't go off. To go off they need a sever shock like a blasting cap.\n\n(IIRC Nobel earned his money inventing dynamite, where nitroglycerine was soaked into sawdust or something - nitro will go boom at the least provocation, as dynamite it was relatively safe. Major advance, much money, he eventually felt guilty about the war-like uses and set up the Nobel prizes.)\n\nBlasting caps - the ones I worked with look like the cartridge end of a rifle bullet, with two wires (or a thin plastic tube) coming out one end. The ones with wires are fired by a current running through the wires. I actually saw people using those plunger-type boxes you see in cartoons. You run the wires far enough away, or around the corner of a cliff, etc - push on the plunger, that spins a magnet which generates a jolt of current - more reliable, no battery needed. Replaced often now by battery and switch. \n\nThe other type of blasting cap is explosion-activated. We had stuff called B-line, a long string of explosive with blast speed measured in thousands of feet a second. Hook this to the second type of blasting cap - tube not wires, and the blast shock from the B-line travels down the thin plastic pipe (about as thick as a pen refill) and sets off the cap. Not terribly relevant for bombs. \n\nSo real simple bomb - stick the blasting cap into the lump of C4. If you're the moron wearing the suicide vest, you have several bricks flattened around your body with a blasting cap in each. Al Queda liked to add nails, ball bearings, etc. around the C$ for maximum damage... sick fuckers. Create some sort of trigger - as simple as a mechanical alarm clock that closes a switch when it goes off, as complex as a fancy timer that can run for months, or something that sets off based on a cellphone ring, etc. \n\nSo real simple - cut the wires to the blasting cap, and while you're at it - yank the cap out of the C4, then if it goes off after that you'll at least only lose a had, maybe an eye or two. \n\nNow I'm Abdul or Liam or Mr. Meinhoff or the Weathermen and my job is to make that more difficult. What do I do? \n\nFirst trick is \"do not disturb\". Something as simple as a pool of mercury in a vial as a switch - if the vial is disturbed, the mercury sloshes, the circuit is closed, Boom! Of course, the stupid thing is the screenwriters for movies like *Speed* think you can put this do-not-disturb on a bus travelling 60mph over California streets. It will take the potholes but it knows if you pick it up...\n\nOne trick was to build a dam around the bomb, pour liquid nitrogen - freeze any mercury switches, as a bonus, kill any battery with extreme cold. So put a thermocouple in the electronics to alert the trigger to any attempt to freeze it.\n\nMaybe put a switch like the one on a refrigerator door, if you open the bomb box or lift the bomb off the ground, switch goes off -deadman switch idea. But if your bomb disposal expert can't even look inside the box, where's the fun?\n\nTo stop the blasting caps being pulled out- maybe have multiple wires going into the bomb - one set is attached to a deadman switch - pull on the wires, closes the circuit, boom. Maybe have the wires with another deadman switch too - shave the C4 off and uncover the switch, it goes off. Have electronics that detect the wire being cut (or short-circuited - another trick, shave off the insulation, short the wires together, no current through the cap). There are two or 3 \"caps\" buried in the C4 - which are real, which are decoy trigger switches? There might even be wires buried in the explosive lump to detect it being manipulated - if you change the shape, the wires touch and boom!\n\nSo the problem is - every bomber has their own tricks - is that the cap or a decoy trigger? Looks like the cap wires, but maybe the bomber cup them off a cap to fool you. Maybe the real cap has red and green wires twisted onto it an inch from the cap inside the C4. And so on...\n\nIt's a war of escalating tricks. What has the bomber done to prevent disarming? As every programmer will tell you about computer programming, or every engineer about devices - too fancy and it will screw up. Just do what's needed - if they won't find it, don't add too many tricks. Plus, as mentioned by others - you need practice to be sure it works - so odds are not every bomb will be a one off; the bomber will learn some stuff and repeat it over and over.\n\nThere have been spectacular screw-ups. _URL_0_\n But of course, anyone setting a bomb needs to be sure it does not go off when you turn it on - how do you know your deadman switches are not on, from transporting the bomb to its location? In 1970 the Weathermen were making bombs and blew up a Greenwich village townhouse. The second round of London Tube bombings fizzled, apparently the home-made detonators did not work and the backpacks just went pop. The shoe-bomber failed because his feet sweated too much and his fuse in his shoe would not light. He went through a whole book of matches. According to one news report, the FBI has a perfect imprint of the bombmaker's thumb in the explosive. The underwear bomber simply set fire to his crotch (!!) another fizzle. ",
"Those of you in this thread may enjoy the kindle single _URL_0_\n\nThe bomb used to conduct this ransom is still used today as an example of an impossible bomb to defuse. Great story and read. ",
"NSA is all the fuck over this thread. haha"
]
}
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"http://electronics.stackexchange.com/questions/129548/why-would-clipping-a-wire-cause-a-bomb-to-explode"
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"https://www.youtube.com/watch?v=KhrWbvT4UHU"
],
[
"http://www.amazon.com.au/Thousand-Pounds-Dynamite-Kindle-Single-ebook/dp/B00M9V9MFW"
],
[]
] |
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1ozb35
|
Who was the first U.S. President to have his photograph taken while in office?
|
I cannot find a reliable source online and have found several answers including John Quincy Adams, Polk, Jackson, Taylor, etc.
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AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1ozb35/who_was_the_first_us_president_to_have_his/
|
{
"a_id": [
"ccx9me5"
],
"score": [
5
],
"text": [
"Based on what I've been able to find out, the earliest *surviving* photo of a president in office is [of James K. Polk.](_URL_2_) However, [this one](_URL_3_) (of his cabinet) and [this one](_URL_0_) of he and his wife might have been taken in any order but they were almost certainly taken while he was in office because he died just three months after leaving. \n\nThose are the earliest surviving (in digitized form, you'd be surprised what you can find in books) photos of a sitting President. Yet there is this mysterious photo of John Tyler. Wikipedia says that Polk was the first to be photographed in office (without citation) but has [this photo of Tyler](_URL_4_), purportedly taken by Anthony, Edwards, & Co. A press release from March 17, 1845 in the New York Herald talks about an exhibition of pictures taken by Anthony, Edwards, & Co. and mentions a portrait of 'ex-President John Tyler'. The portrait is not described and neither is the date on which it was captured. Another press release mentions the gallery on March 13, implying that it was a multi-day event. Tyler only left office on March 4. It is possible that a photo of Tyler was indeed taken while he was still in office. Further corroborating this is a brief blurb [here at the Encyclopedia Virginia](_URL_1_) which mentions an advertisement from 1844 from Anthony, Edwards, & Co. claiming to have photographed Tyler. It is as yet unclear when exactly the existing daguerreotype of Tyler was taken, though I conclude that it is certainly possible for him to have been photographed in office. "
]
}
|
[] |
[] |
[
[
"http://upload.wikimedia.org/wikipedia/commons/6/6a/James_K_Polk_and_Sarah_C_Polk.jpg",
"http://encyclopediavirginia.org/media_player?mets_filename=evr7581mets.xml",
"http://upload.wikimedia.org/wikipedia/commons/f/f8/James_Polk_restored.jpg",
"http://upload.wikimedia.org/wikipedia/commons/8/82/State-dining-room-polk-cabinet.jpg",
"http://upload.wikimedia.org/wikipedia/commons/5/55/Tyler_Daguerreotype_%28restoration%29.jpg"
]
] |
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6kdtdt
|
what is cherenkov radiation?
|
I saw the nuclear reactor gif earlier and I've e heard of and seen CR on the internet before. What is it and why does it happen?
Ps. Sorry if this is a reposted question, I couldn't find a previous discussion on the topic.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6kdtdt/eli5what_is_cherenkov_radiation/
|
{
"a_id": [
"djlasm7"
],
"score": [
7
],
"text": [
"In a nutshell, it’s like a sonic boom, but instead of going faster than sound, it goes faster than light. Instead of going BOOM, it’s a flash of light/radiation. Nothing goes faster than light in a vacuum. However, through a medium like water, light slows down so some subatomic particles can go faster than it. Usually, they’re trying to find neutrinos when you’re talking about Cherenkov Radiation. Since neutrinos don’t really interact with anything, what they do is fill a huge room with water and light detectors. Then they wait and hope one of the quadrillions of neutrinos passing through the room interact with the water causing a brief flash (Cherenkov Radiation)"
]
}
|
[] |
[] |
[
[]
] |
|
a5y24v
|
is there a reason spicy things become less spicy after being refrigerated?
|
was eating leftover wings and became curious
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a5y24v/eli5_is_there_a_reason_spicy_things_become_less/
|
{
"a_id": [
"ebq6oeh"
],
"score": [
5
],
"text": [
"Cold numbs your taste buds. So it's not less spicy your mouth just doesn't register the capsaicin like it would if the wings were hot."
]
}
|
[] |
[] |
[
[]
] |
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