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2l43qs
|
why does the us use fahrenheit when the rest of the world uses celsius?
|
Wouldn't it be more productive to just teach our children Celsius and save them the trouble of learning 2 different measurements of temperature?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2l43qs/eli5_why_does_the_us_use_fahrenheit_when_the_rest/
|
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"Because most of us are around 5 feet 7 inches and weigh around 200lbs and drive at an average speed of 50 miles per hour and have temperatures of 98.6 degrees Fahrenheit. \nThe US customary system developed from English units which were in use in the British Empire before American independence. Consequently most US units are virtually identical to the British imperial units. However, the British system was overhauled in 1824. Advocates of the customary system saw the French Revolutionary, or metric, system as atheistic. ",
"The Americans weren't invited (by the French) to the summit where the rest of The World/Europe made standardized units. \n\nI believe the podcast \"how stuff works\" had an episode about this a few years ago.",
"There is no valid reason why you shouldn't be using it.\n\nIt does carry a significant cost in both time and resources to change though. I remember when we did it in Canada. It is not a small job to change how you measure pretty much everything. That may be why you still haven't adopted it.",
"Whenever people get into a metric vs. US debate, they make it seem like Americans have no idea what the metric system is. We use both, we learn both, we just use our system more.",
"There is really no reason to change. Metric is used where necessary/practical here.",
"Let's build a cube. A meter tall (or 100 centimeters, 1,000 ..*millimeters*) wide and deep. Let's now fill it with water: Exactly 1,000 liters of water will be needed. For a weight of 1,000 kilos, or a ton. This water will boil at 100 degrees C and freeze at 0C.\n\n*oh my god metric's haaaard, man!*",
"All joking aside, Americans actually learn both, and use them interchangeably. I.e. Soda comes in 2-liter bottles, milks comes in gallons, hospitals measure liquids in cc's, and weigh/measure newborns in pounds/feet and inches."
]
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1meqgg
|
how can a country sell bonds with negative interest rate?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1meqgg/eli5how_can_a_country_sell_bonds_with_negative/
|
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"They can't and don't.\n\nThe thing is that inflation happens. So if the nominal interest rate on the bonds is less than the rate of inflation, the *effective* interest rate is negative. They're still a good deal, though, because cash is also affected by inflation; keeping your money in cash would just make you lose more."
]
}
|
[] |
[] |
[
[]
] |
||
62ya8y
|
what's the process to get into u.s from mexico legally (immigrate)?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/62ya8y/eli5_whats_the_process_to_get_into_us_from_mexico/
|
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"It depends. The US will offer x amount of work visas every year for jobs where there are a shortage of American workers (it could be working on farms or being a doctor), student visas and travel visas (you don't need a visa to visit the US if you are Mexican) \n\nAfter you get your foot in the door you are only allowed to stay for until your visa expires. After that you are supposed to return. If you want to legally stay, you have to apply for permanent resident status (which means you are not a citizen, but are legally entitled to stay permanently [a green card]). This can by done a few ways. First, you can apply based on family ties, if you marry an American you can apply, if you are unmarried but are the offspring of an US citizen, etc. If you posses extraordinary capabilities or training, if it is of the national interest or if you belong to a group that is being persecuted and your country's government does not have control of the situation, or are a refugee you can apply for refugee status. If you belong to the last group the state department will investigate your case and grant or deny you asylum; all require an interview with US Citizenship and Immigration Services.\n\nEmployers can also petition the government to grant x amount of visas to do x job because these jobs require workers to be in the US for extended periods of time and there are not enough people in the US that can do it.\n\nAll th is does not grant you citizenship, it grants you the right to live in the US, you do not serve on jury duty, there are certain benefits you are not eligible for but you are fully protected by the constitution (even if you are here illegally).\n\nGenerally, if you h ave no special skills then you will not be granted a green card."
]
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|
[] |
[] |
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[]
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||
4wzn0d
|
Why do some places have two high and two low tides a day, and other places have only one?
|
[deleted]
|
askscience
|
https://www.reddit.com/r/askscience/comments/4wzn0d/why_do_some_places_have_two_high_and_two_low/
|
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"In short, this is because the ocean basins aren't uniform and tides don't have the same impact in all areas. Imagine sloshing water back an forth in a bucket- there will be areas that experience more extreme water level change relative to the regular surface level. \n\nThere are certain areas in the oceans, nodes, which would be like the center of the bucket when sloshing the water: the water height stays relatively level"
]
}
|
[] |
[] |
[
[]
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|
bzjaoc
|
what is academic probation and how would somebody get it?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bzjaoc/eli5_what_is_academic_probation_and_how_would/
|
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"It means your grades are shit and if you don't shape up you're out.\n\nThis is more typical in colleges or private schools since they don't want some slacker tanking their performance numbers.",
"It's when your grades are poor so the school you go to warns you. If they don't improve, there will be negative consequences such as losing funding, certain privileges, or just plain getting kicked out of school.",
"Academic probation happens to a person when their grades drop below a certain level. It usually happens when a person is really struggling with their class work, or when they simply stop doing it altogether. The GPA a person needs to drop below to be placed on academic probation varies from school to school, but it’s usually between the 2.0-2.5 range."
]
}
|
[] |
[] |
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[],
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||
2er3kp
|
What were the intentions of Edward, the Black Prince, preceding the battle of Poitiers (1356), was he looking to confront King John II of France?
|
It has been some time since I reviewed the primary sources so please correct me if I'm wrong, but I believe that the Chronicles of both Jean Froissart and Geoffrey le Baker, as well as a couple others, describe the prince as having every intention of fighting the battle at Poitiers. Furthermore, considering the outcome of the battle and the extensive preparations taken on behalf of the Black Prince's army, the notion that the Black Prince had always planned on confronting King John II isn't too far-fetched. For those of you unaware of the outcome, despite outnumbering the English ~3:1, King John II was captured and the French army was thoroughly crushed.
However, in a letter written to his father, Edward himself states that he was attempting to retreat from King John's forces. Likewise, the movements of his army in the weeks preceding the battle imply that the Prince was seeking to return to the safety of Bordeaux. The Black Prince's victory at Poitiers can be seen as evidence of his brilliance as a military tactician. Considering the sheer size of King John's army, and that Edward had no way of knowing how poorly organized and undisciplined it was, it seems reasonable to conclude that, as a military commander, the best option would be a tactical retreat.
I'm interested in hearing why historians, in their own opinion, either believe the Prince was or wasn't retreating.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2er3kp/what_were_the_intentions_of_edward_the_black/
|
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"Are you referring to the letter Prince Edward sent to the City of London following his victory? Edward doesn't exactly say he was planning on retreating. Instead, he says he was withdrawing to link up with the Duke of Lancaster after abandoning an assault on Tours. After he rejected the French negotiators, Edward waited at Chatelleraute for four days in order to determine where exactly the French king and his army were. After that, it was in fact Edward who was pursuing the French, rather than the other way around. After that, the campaign was a messy series of maneuvers and skirmishes as both armies attempted to locate the other. Edward was clearly intending on having a battle, but it would be on his terms and on terrain carefully chosen to protect his men from the French attack. \n\nThe Poitiers campaign is (in terms of strategy) not very different from the Crecy campaign, or the Black Prince's 1355 *chevauchée* (although in that case, the French refused to come out to fight in the field). It is a common misconception that the English engaged in *chevauchées* in order to avoid confrontations with larger French armies. Most sources point to the exact opposite scenario: the English actively desired open combat in the field, while the French only attacked marauding English armies when they felt they had no other choice. The English knew that their armies were highly effective in the field, and frequently won battles against numerically superior foes. The prospect of engaging larger forces was not a cause for much fear, provided that the English were able to maneuver so that they 1)fought the battle on favorable terrain and 2)prevented multiple French forces from enveloping them. What has often been interpreted in the past as English armies being chased by French armies is more often English armies attempting to maneuver in order to pick the best location for open combat. For more on English military strategy in the opening stages of the Hundred Years War, I highly recommend Clifford Rogers' *The Wars of Edward III: Sources and Interpretations*."
]
}
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[] |
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ztcu2
|
How common was it to be executed for being a "witch" around the time of the Salem Witch Trials?
|
I don't know much about this other than references to it in pop culture and would like to know more about like how many people were killed, was it really that easy to accuse someone of being a witch, what was the most common punishment, etc.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/ztcu2/how_common_was_it_to_be_executed_for_being_a/
|
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"By the time of the Salem trials the witch craze was already well into its decline. It was an anomalous outburst for the time. If you want to know the witch craze in general I can talk a bit about that, though I only really know about the European trials, and only English ones in any detail.\n\nDifferent parts of Europe experienced the witch craze differently, and to different degrees. In the mainland (Germany, France, etc), the witch hunts were an institutionalised phenomenon presided over by the Church and enforced by the local authorities, from the top down. Witchcraft was considered a form of heresy, and so the Inquisition was granted the power to carry out its own investigations. Continental witches were believed to be part of an organised cult in league with the devil as part of some grand diabolical conspiracy. They were tortured for confessions and forced to name names, tried in ecclesiastical courts as heretics and burned alive. \n\nEngland's treatment of witchcraft was quite unique. For a start, the Catholic Church had no authority there, which meant no Inquisition. Accusations arose from within local communities, rather than from above. With the exception of Matthew Hopkins (the self styled Witch Finder General'), there was never any attempt by the authorities to incite a witch hunt. Witchcraft was not seen as a heresy, but rather as an extreme form of public disorder. There was no conspiracy, no 'witch cult', no witch's Sabbath, no flying and rarely any references to a diabolic pact. In fact English witches had a pretty boring time, though unlike continental witches they did get to have [familiars](_URL_0_), which I guess is kinda cool. English witches were usually tried by jury in secular, common law courts just like any other felon, and the guilty were hanged rather than burned.\n\nIn England, accusations of witchcraft tended to follow a basic narrative. Typically they would begin with an old woman going door to door begging for alms, and then being turned away by a disgruntled neighbour. Some tragedy would inevitably befall the neighbour, who would then accuse the old woman of witchcraft. It's amazing how many pamphlets from the time describe cases that follow this exact pattern. So how easy was it to accuse somebody? Quite easy. But it wasn't unheard of to be found innocent. In fact, it was relatively common. Some courts were naturally reluctant to prosecute something so unprovable, and if you could find enough people to vouch in your favour, you could be let off automatically.\nTrials on the continent were significantly scarier due to the use of torture and the large amount of authority given to individual judges/inquisitors to prosecute witches.\n\nThe total number of executions is usually estimated to be around 40 to 50,000, but higher estimates do exist."
]
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[] |
[] |
[
[
"http://gallery.nen.gov.uk/assets/0702/0000/0341/hopkins_mid.jpg"
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26rwh1
|
Has the water released by combusting hydrocarbons had any effect on the environment?
|
I've always heard about the effects of additional carbon dioxide from burning fossil fuels on the environment, but what about the additional water?
|
askscience
|
http://www.reddit.com/r/askscience/comments/26rwh1/has_the_water_released_by_combusting_hydrocarbons/
|
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"Absolutely! Water vapour, like CO2, is a greenhouse gas. Water Vapour released by combustion--but this isn't the sole source for water vapour, of course--helps create a sort of positive feedback loop in the atmosphere, increasing the amount of warming experienced by climate change. \n\nGenerally, Water vapour tends to double the amount of warming; if we were to experience an increase of 1°C from CO2 alone,, water vapour would make it more like 2°C. \n\nSo water vapour is an extremely powerful greenhouse gas. However, and this is the most important point, it's also a fairly short lived greenhouse gas. Whereas CO2 can stay in the atmosphere for a very long time, Water Vapour condenses into clouds and returns to the water table in fairly short order. Water Vapour might only stay in the atmosphere for a few weeks, whereas CO2 can last centuries. "
]
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[] |
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67tp73
|
If an electric motor is supplied power but restricted in turning (like holding back a ceiling fan) what is happening which would cause it to 'burn up'?
|
askscience
|
https://www.reddit.com/r/askscience/comments/67tp73/if_an_electric_motor_is_supplied_power_but/
|
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"If it has separate windings with a commutator bar, all that current is only going though one winding instead of all the windings taking turns. Also, if a motor is turning, it also acts as a generator from the spinning motion which produces a backvoltage which limits the current.",
"The electrical current will continue to increase trying to force the motor to move and you will hopefully blow a fuse or pop a breaker before burning up a motor. What is actually happening is that the spools of wire inside the motor, although they look like bare wire, are insulated and too much current causes the wires to heat up and the insulation melts and shorts the wires together. The smell of a bad motor is the plastic insulation having melted and one or more if the \"legs\" has grounded out.",
"When a motor is turning, that rotation generates a voltage, a 'back EMF', that acts against the flow of current. It is this voltage, not the resistance of the coils, that restricts the amount of power the motor draws. And as this is an impedance, it doesn't generate heat. The power - the current in the motor pushing against this voltage - is what turns the motor.\n\nWhen the rotor is locked, there is no back EMF to impede the flow of current through the motor. All the electricity flowing through the motor is converted to heat by the resistance of the windings. This quickly overheats the wiring, melting insulation, creating shorts, reducing the resistance and further increasing the current, until some wiring melts and blows.",
"Typically a circuit breaker triggers when the current gets too high (no turning means no back emf as others have stated so too much current ). This is only a temporary cut off so the switch goes back to on after a short time and the motor starts again, leading to a stuttering. \n\nIf this safety measure is not included, then the fan can overheat and burn up. ",
"Along with the counter EMF that allows more current that many people have mentioned, the motors typically have a small fan to cool the motor components also. This is usually a problem when you use a VFD (varies frequency of power going to the motor to speed up or slow down the motor) on a motor not rated for that use.\n\nSo basically more amps and less cooling. ",
"[This](_URL_0_) is a good description of a typical motor model.\n\nIf you look at the diagram, you see the armature circuit. That's what you connect your power to. It has a resistance, an inductance, and a back EMF. The back EMF is proportional to the rotor speed. The resistance is typically small. The motor I have here on my bench measures around 4 Ohms. \n\nIf you put in a constant voltage, you ignore the inductor part. If you hold the rotor steady, you ignore the back EMF part. All that's left is the armature resistance; input current is V/Ra. \n\nThis can be a problem because 1. 100% of that energy is dissipated in the winding, when some of it was supposed to be put out as mechanical energy, vibration, noise, rotor friction, etc. That's more than the armature is typically built to handle. And 2) it is, by definition, the maximum current the motor can handle. You're maximizing power in and minimizing efficiency, meaning the power goes to things it wasn't supposed to. ",
"The reason this happens is because the rotor is locked and there is no rotation to induce counter electromotive force (EMF) in the motor. I see others have called it \"back EMF,\" but it is the same thing.\n\nTo understand counter EMF, think of Newton's Third Law. For every action, there is an equal and opposite reaction. When a rotor rotates, it induces an electromagnetic force opposite of the direction of rotation. In an ideal situation the two forces balance out when there is a constant load and that is how you get your running current. Starting current is much different. As others have pointed out, before the rotor begins to turn and generate counter EMF the stator (armature) windings are essentially a short circuit. Those windings are not rated to handle that amount of current outside of starting surges. Because of a phenomenon called copper loss, all conductors generate heat as current flows through them. The amount of heat generated is proportional to current and calculated as P=I^2 * R. As you can see, the power dissipated (heat) grows exponentially with current. With nothing to limit the current flow in a locked rotor it is only a matter of time before any stator (armature) windings heat to the point of failure. If you are curious, there is a document that exists that explains a lot of these principles. The \"Applied Engineering Principles Manual\" can be found at _URL_0_ and you would want to start reading at around page 23 or so.",
"The coils are actually not that sturdy. If you took them out of the motor, and applied the regular voltage, they would go up in a puff of smoke.\n\nIn the motor, while it's turning, the interaction between coils and magnets generates an opposition (an opposed current) to the free flow of current through the coils. That's what keeps them from burning up.\n\nAnother way to look at it: when it's spinning, some of the power drawn from source goes into heating the coils, some goes into spinning the motor (well, ideally almost all power should go into spinning the motor). If it's not spinning, then ALL power goes into heating the coils - of course they go POOF.",
"This is also what happens to an acoustic speaker when it fails... A speaker driver is basically a motor that operates by the same Faraday law.\n\nThe voice coil heats up to a very high temperature and that causes the voice coil-former glue to melt and the speaker driver fails. ",
"The windings of a motor are inductors. When the motor is spinning, the voltage being applied to the inductors is constantly changing directions. When inductors are presented with a high frequency signal, they store energy in the form of a magnetic field, and then subsequently release it back into the circuit. During this process, since the energy in is equal to the energy out, the inductor produces very little heat. When you force the motor to stop turning, the voltage stops changing direction. When a constant voltage is applied to an inductor, it acts like a wire. This wire is forced to dissipate all of the energy entering the motor as heat. "
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"http://ctms.engin.umich.edu/CTMS/index.php?example=MotorSpeed&section=SystemModeling"
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"http://www.navsea.navy.mil/Portals/103/Documents/NNPTC/Electrical%20Eng/applied_ee_v1.pdf"
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3ysjni
|
why don't stars appear red but white? It is said that only red colour sustains when light travels a long distance!
|
askscience
|
https://www.reddit.com/r/askscience/comments/3ysjni/why_dont_stars_appear_red_but_white_it_is_said/
|
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"Some stars, such as Betelgeuse (in the corner of Orion) are noticeably red. Red stars are usually either dwarves or giants, but we can only see the giants without a telescope.\n\nHowever, the process of emitted light reddening over long distances (either due to absorption by dust or the expansion of the universe) occurs over distances much, much larger than the distances to visible stars in our galaxy.",
"Red travels a longer distance *through an atmosphere* because the other colors are scattered in other directions more readily. This is why the sun looks red at night– the red light from the sun can travel through greater distances of atmosphere while the other colors are scattered. This is not the case when light travels through space: there isn't any atmosphere for the light to be scattered off of, so regardless of the distance the star is from us we'll basically see its true color.",
"That 'appearance of the stars' is a matter of how your eyes work.\nAt low light levels we don't perceive color. We just 'see' a source of light as 'white'.\n\nOur vision in low light depends on color blind receptors, (Rod type), in our retinas. The color sensitive ones, (cone type), only function at higher illumination levels.\n\n The Red Shift referred to by other posters does exist, but it applies to only \nminiscule shifts in any star-light you are likely to see with the naked eye.\n"
]
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3sadom
|
To what extent did Alexander the Great/Hellenism pave the way for Christianity?
|
Inspired by the song "Alexander the Great" by Iron Maiden:
_URL_0_
The lyrics in question come from this verse:
"Hellenism he spread far and wide
The Macedonian learned mind
Their culture was a western way of life
He paved the way for Christianity"
Would Christianity have had the same succes if not for the conquests of Alexander the Great?
Would it have spread in a different direction faster?
Thanks for any replies!
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3sadom/to_what_extent_did_alexander_the_greathellenism/
|
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"This is a pretty complicated question and, largely, is based on an interpretation of the histories of Alexander that is now considered unfeasible. That, however, doesn’t mean that there isn’t some truth to the claim. I don’t have the time to find my sources right now so this is going to be a bit informal.\n\nWhy it’s wrong:\n\nEarly modern Alexander scholarship was dominated by some British guy (sorry I don’t remember his name) who saw Alexander as basically a pre-Jesus. After Alexander finished with his conquests, he started taking on Persian customs and airs. The scholar saw this as proof of Alexander being an equalizing force: by elevating conquered Persians to the level of their Greek counterparts, Alexander was declaring equality of man. Christianity, which is a universal in its acceptance, spread easily because of the progressive framework wrought by Alexander’s liberal policies.\n\nEnter Badian. Basically the old British dude was the premier Alexander scholar until Badian showed up, slapped him around, and took his throne. Alexander’s ‘persianization’ Badian said, was not an attempt at syncretism but rather an attempt to fully adopt the Persian system. Alexander’s position on top of the Greek world was rather tenuous: Athens and Sparta were constantly angling for independence and Alexander’s supremacy was only guaranteed through military might. In contrast, the Persian monarchal system was steeped in tradition and (largely) unwavering loyalty for their ruler. Furthermore, in terms of bureaucracy, the Persian system was significantly more advanced and efficient. Think feudal lords paying tribute (Greece) compared to a much more modern taxation and levy system (Persia). It was therefore in Alexander’s best interests to position himself as a successor to Darius III rather than as a foreign invader. Badian also did a lot of detailed textual analysis (both scholars based their conclusions largely on the works of Plutarch and Arrian) that made the British dude’s claims look silly.\n\nWhy it’s right:\n\nOk so this concept was created by the wishful thinking of some British historian who wanted to see Jesus everywhere he looked. It is not, however, completely without merit. Christian thought was not created from a vacuum but rather, in many ways, can be seen as an extension of earlier Greek thought: For instance, despite Augustine’s professed rejection of Greek thinkers, many of his arguments rest on distinctly Greek premises. The similarity can be seen quite easily: take a Greek concept like Plato’s allegory of the cave and replace the conclusion with Jesus/God’s love etc. and you get a rough approximation of Christianity. Aristotle can be such a boring read because (in the Judeo-Christian tradition) we have accepted his ideas so completely that they seem utterly dull and obvious. Furthermore, in many Christian traditions there’s some sort of intercession (usually by Mary) to rescue saintly sinners from hell. These sinners are people in hell who were not saved by virtue of being born before Jesus and are invariably composed of famous Greek thinkers.\n\nBasically, the idea is that the universal acceptance of Hellenic ideals allowed for an acceptance of a theology that is created in a Greek framework. Furthermore, the lack of strict language/cultural/political boundaries allowed for dissemination of ideas across vast tracts of land. This created the perfect infrastructure for the spread of Christianity; which is already a pretty liberating and attractive ideology if you (as most non-elite people during this era were) are living in the shit. \n"
]
}
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[] |
[
"http://www.azlyrics.com/lyrics/ironmaiden/alexanderthegreat.html"
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[
[]
] |
|
2eyfpl
|
Why do some smells travel faster and propagate farther than others?
|
For example, there are some foods that you can only smell from up close, but others you can smell from across the house.
Also, some non-spray air fresheners seem to fill a room or car faster than others.
|
askscience
|
http://www.reddit.com/r/askscience/comments/2eyfpl/why_do_some_smells_travel_faster_and_propagate/
|
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"It has to do with the diffusion rate of the molecule. Smells are composed of molecules that bind to the receptors present in the nose; if the nose has a receptor for a certain molecule in the gaseous state, then the gas will \"smell.\" The potency of a smell depends on the concentration of the molecule in the atmosphere and on how fast those molecules can travel through the rest of the gas in the air. Because the smell molecules must travel through the atmosphere by bumping into other atmospheric molecules, those molecules of smaller mass and size tend to move more quickly and thus diffuse across a room with greater speed. "
]
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|
[] |
[] |
[
[]
] |
|
qjegb
|
At what altitude does the sky cease to be blue?
|
Is it always blue until you leave the atmosphere?
|
askscience
|
http://www.reddit.com/r/askscience/comments/qjegb/at_what_altitude_does_the_sky_cease_to_be_blue/
|
{
"a_id": [
"c3y291h",
"c3y5p0v",
"c3y5q4l"
],
"score": [
20,
8,
4
],
"text": [
"I will answer your question with a question.\n\nAt what point does the red become blue in the following image?\n\n_URL_0_",
"Sky gets dark at around 30 kilometers. You can see stars during the day at these heights.",
"The atmosphere ends gradually -- it fades out. By tradition we often say it's over at about 100km, but that's arbitrary. The sky starts to look dark far below that point, and there is still a minuscule amount of gas up at the altitude of the International Space Station."
]
}
|
[] |
[] |
[
[
"http://d2o0t5hpnwv4c1.cloudfront.net/612_gradients/webkit.jpg"
],
[],
[]
] |
|
1so2vn
|
Is there a lot of variance between people in how much energy they are able to extract from food they digest?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1so2vn/is_there_a_lot_of_variance_between_people_in_how/
|
{
"a_id": [
"cdzk5n7"
],
"score": [
8
],
"text": [
"I'm not sure I can answer the question for _all_ aspects of our physiology...however, I will say that there is some fascinating microbiological evidence to suggest that the answer to this question is \"yes.\" \n\nStudies have shown that the bacteria that live in our gut (the **microbiome**) influence our likelihood of developing obesity, metabolic disorders and diabetes. We have already established that these organisms assist our absorption of nutrients. We're starting to understand that _variability_ in these organisms may lead to _variable_ absorption of nutrients from food among different people. Specifically, studies have shown that obesity is associated with a decrease in the diversity of the gut microbiome. That is, people who are overweight/obese have fewer different _types_ of microorganisms colonizing their intestine. It has been shown that the organisms that are winning out (_Firmicutes_) have an increased capacity to harvest nutrients.\n\nThere's additional research being done to investigate how these microscopic critters affect inflammatory processes going on in the intestine that might affect myriad metabolic disorders.\n\nThe gut microbiome is an exploding new field of research, and there's much that remains unanswered about its effect on health and illness. Regarding your question, however, it seems that bacteria may play a role. \n\n**Seminal Paper**: Turnbaugh, P.J., Ley, R.E., Mahowald, M.A., Magrini, V., Mardis, E.R. and Gordon, J.I. “An obesity-associated gut microbiome with increased capacity for energy harvest.” Nature, 2006.\n\nEDIT: In the spirit of procrastination from what I _should_ be working on, I added more details and cited one of the foundational studies."
]
}
|
[] |
[] |
[
[]
] |
||
1jbyki
|
how do we know the articles from /r/politics and anything the media shows is actually real?
|
Who do I believe? If I don't know the proper way to believe something?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1jbyki/how_do_we_know_the_articles_from_rpolitics_and/
|
{
"a_id": [
"cbd5lat"
],
"score": [
2
],
"text": [
"You should treat everything you read with a healthy dose of skepticism. /r/politics is quite bad in that it commonly uses extremely biased news sources. If you read it in /r/politics, chances are it's only one part of the story. Get your news from multiple reputable sources, such as the NY Times, Al Jazeera, PBS/NPR, etc. "
]
}
|
[] |
[] |
[
[]
] |
|
5ycq05
|
How populist was the American revolution? Was it a movent by the elites or did the lower classes support it?
|
Thanks
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5ycq05/how_populist_was_the_american_revolution_was_it_a/
|
{
"a_id": [
"dep2xw5"
],
"score": [
17
],
"text": [
"So contrary to popular belief, the \"Founders\" were not the main proponents of separation from Great Britain -- quite the contrary. Most Founders were quite hesitant to pull away. However, populist movements really started to become prevalent by the end of the 1760s. \n\nTo explain, Founders like John Adams had a long history of fearing Democracy and many other aspects of their future government. Check out [Adams' own early view of democracy](_URL_2_) in 1763:\n\n > Democracy, will soon degenerate into an Anarchy, such an Anarchy that every Man will do what is right in his own Eyes, and no Mans life or Property or Reputation or Liberty will be secure and every one of these will soon mould itself into a system of subordination of all the moral Virtues, and Intellectual Abilities, all the Powers of Wealth, Beauty, Wit, and Science, to the wanton Pleasures, the capricious Will, and the execrable Cruelty of one or a very few.\n\nYeah, not very flattering, is it? However, his views eventually evolved as the situation in America became more severe.\n\nBy the early 1770s, populist movements across America really shifted American politics as a whole. Books like Marjoleine Kars' *Breaking Loose Together: The Regulator Rebellion in Pre-revolutionary North Carolina* outlines the ways that populist movements in the South were able to fight back against corruption and the government (mainly between 1766 - 1771). This is important because \"Regulator Rebellions\" had a direct impact on what happened after the war.\n\nBetween 1772 - 1775, a lot changed, and most was spurned on by the general public. Everyone knows about the Boston Tea party, but most people don't realize that the Boston Tea Party caused a ripple affect with Tea Parties all across America in 1774. Tea Parties happened in many American cities, including [Philadelphia, Annapolis, Charleston, and many others](_URL_1_). This forced the gentry into a precarious situation. Some, like Charles Carroll of Carrolton [corresponded with his father about this in 1774](_URL_3_), essentially saying that while he doesn't think that these protests are a good thing, the rich and powerful must get involved in American politics so they can secure their place in America's future. \n\nThat's why the tone of the early Continental Congress is very tame. Internal proceedings show that many states, especially in the South, leaders were not keen to even consider separation from Great Britain. But the challenge was that as the Continental Congresses met, the people back home kept protesting, and burning down the houses of tax collectors, or kicking governors out of their homes. A great book that tackles this is Terry Bouton's *Taming Democracy: The People, The Founders, and the Troubling End of the American Revolution* where he correctly ascribes many of the Founders to be hesitant leaders towards independence. It also explains why, even after minor hostilities broke out in 1775, the Founders still sent the \"[Olive Branch Petition](_URL_4_)\" back to Britain as they vainly hoped to stop a full war before it happened. Even when the Continental Congress empowered General George Washington with command in June 1775, they did not expect that his duties would necessarily be a full-break with Great Britain. The Continental Congress wanted some autonomy from Great Britain and some representation in government, which they believed was more achievable than independence. \n\nNow I should disclaim that this isn't true of all Founders. Some, especially in the North were much more pro-separation than many others. [Samuel Adams](_URL_0_), who was very vocal and active during the Stamp Acts protests, helped organized the Boston Tea Party, and was a member of the Continental Congress Representing Massachusetts was very vocal from the beginning that he believed separation from Great Britain should be a primary goal. There are a few others that fall into this category, but not many. \n\nTl;Dr: Most founders dragged their feet as the American \"mob\" dragged them forward . \n\nEdit: fixed a misspelled name. "
]
}
|
[] |
[] |
[
[
"http://www.biography.com/people/samuel-adams-9176129#synopsis",
"http://rethinkingtherevolution.com/blog/2016/teaparty",
"https://founders.archives.gov/documents/Adams/06-01-02-0045-0008",
"https://archive.org/details/gb2ZLwslLZQnQC",
"http://www.history.com/this-day-in-history/congress-adopts-olive-branch-petition"
]
] |
|
43k7v1
|
why would a country implement negative interest rates (ie. japan)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/43k7v1/eli5_why_would_a_country_implement_negative/
|
{
"a_id": [
"czisd2a"
],
"score": [
2
],
"text": [
"Yes. That's exactly why they did it. They are suffering a recession right now, and this would stimulate people to take their money and spend it, giving a boost to the economy."
]
}
|
[] |
[] |
[
[]
] |
||
3awpj2
|
How common is it for a planet to have a natural satellite like our moon?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3awpj2/how_common_is_it_for_a_planet_to_have_a_natural/
|
{
"a_id": [
"csgt30f",
"csgtevz"
],
"score": [
3,
18
],
"text": [
"Consider the solar system as we know it. Of the 8 major planets, all but 2 (Mercury & Venus) have at least one natural satellite, most have more. Mars 2, Jupiter & Saturn 60+ each, Uranus & Neptune 27 & 14 respectively. Even the dwarf planets have satellites, Pluto has 5.",
"Natural satellites seem to be pretty common amongst planets. 6 out of 8 planets have at least one moon, and many dwarf planets as well as some asteroids also have moons. \n\nWhat's remarkable is the size and mass ratio of the earth-moon-system: It is 1: 3,67 for the size and 1:81 for the mass. In other words, the moon is really big compared to its mother planet. Similar sized moons orbit only gas giants, where the mass and size ratio is much smaller, because the gas giants are so much bigger and heavier than earth. \n\nThe reason why a comparatively small planet like earth has such a big moon lies in the formation of our system. It is very likely that a mars-sized object shared and orbit with the young earth, which eventually lead to their collision. The heavy core of that object contributed a significant amount of metals like iron and nickel to the earth, while lighter stuff like rock was spewed into an orbit and coalesced to finally form our moon. That's a nice explanation for why we have such a big moon and why earth is so big and **dense** amongst the terrestrial planets. \n\nThe only system which seems similar to ours is actually not a planetary system, but a dwarf planet system, namely the one of Pluto and Charon. The size and mass ratio is even bigger here, since Charon has more than half the diameter of Pluto and about 1/8 its mass. That causes the barycenter to be outside of Pluto, why some people think it should be considered as a own type of system called a double planet. The probe [New Horizons](_URL_0_) is going to visit the system this july and is already sending data to earth. Perhaps we will learn more about our own system by studying that dwarf planet. \n\nRegarding moons of planets outside the solar system, the so called [exomoons](_URL_1_), we don't have many data yet, because our technology is still in early development. There are some good candidates listed in the linked article and our own solar system suggests that moons seem to be pretty common, but we still have to improve our observational instruments to get information how common moons around other planets are and what properties they have. "
]
}
|
[] |
[] |
[
[],
[
"http://www.nasa.gov/feature/new-from-nasas-new-horizons-increasing-variety-on-plutos-close-approach-hemisphere-and-a",
"https://en.wikipedia.org/wiki/Exomoon"
]
] |
||
1la3d6
|
What would happen when light reflects off of a mirror, if the mirror was artificially heated to have a higher net energy than the particle does?
|
Would the particle receive the energy during the reflection, or would the additional heat make no difference? (my "guess" is that it would be impossible to heat something to a high enough temperature for it to retain it's ability to reflect, and instead the mirror would fail.) Apologies if my question is phrased poorly.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1la3d6/what_would_happen_when_light_reflects_off_of_a/
|
{
"a_id": [
"cbxaa3e"
],
"score": [
2
],
"text": [
"What do you mean \"higher net energy\"? The total heat energy in a given mirror is typically much higher than the energy of a given photon in the visible spectrum."
]
}
|
[] |
[] |
[
[]
] |
|
zav98
|
Is it possible to for the body to stop identifying an allergen as harmful after years of no exposure?
|
askscience
|
http://www.reddit.com/r/askscience/comments/zav98/is_it_possible_to_for_the_body_to_stop/
|
{
"a_id": [
"c62z7d0"
],
"score": [
3
],
"text": [
"Actually, yes! Memory B-cells are what are responsible for long term humoral immunity (the kind involved in allergic reactions, among other things). Memory B-cells are some of the longest lived cells in the body, behind maybe neurons and cardiac myocytes, but even then they only live about 20 years. Without some kind of stimulation since the first incident, it's entirely possible that the clonal population your body created after your sting at age 12 has since died off or diminished to the point where you're anergic to yellow jacket venom."
]
}
|
[] |
[] |
[
[]
] |
||
4yq3nq
|
In the history of presidential elections in the United States has a major political party ever functionally conceded defeat months before the general election and ran its house/senate candidates as checks on the opposing party's candidates power once they assumed the presidency?
|
Recently it has been in the news that officials and house/senate candidates for the Republican party are considering writing off their general elections candidate and instead running as "checks" on the power of a presumptive Democratic president. Has this happened before in previous US presidential elections or would this strategy be historically unprecedented in US politics?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4yq3nq/in_the_history_of_presidential_elections_in_the/
|
{
"a_id": [
"d6psrkd"
],
"score": [
2
],
"text": [
"Republicans ran Congressional campaigns in 1996 (Clinton/Dole) explicitly as a check against the presumed Clinton victory. (Clinton was up 8 points in October polling.) The NRCC warned against giving Clinton a blank check and pushed for voters in vulnerable districts to split their ballot."
]
}
|
[] |
[] |
[
[]
] |
|
1llu2k
|
why do humans drink so much water when compared to cats/dogs?
|
I saw a video of a cat drinking water yesterday, and the cat was there for ~2 mins, just lapping up water. The structure of cats/dogs is pretty much the same compared to humans, right? What fundamental difference do cats/dogs have which allows them to survive with such little water.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1llu2k/eli5_why_do_humans_drink_so_much_water_when/
|
{
"a_id": [
"cc0i7cn"
],
"score": [
7
],
"text": [
"Humans sweat while most other animals with fur/feathers don't. Obviously you need to replace the moisture lost by sweating. \n\nEfficency of our bodies is another issue. Some animals have more efficient kidneys that concentrate urine stronger than humans. This means they need less water to carry away waste."
]
}
|
[] |
[] |
[
[]
] |
|
1am2hh
|
Is it really possible to "utilize the natural electric currents within the earth" and convert it into "radiant electricity?"
|
askscience
|
http://www.reddit.com/r/askscience/comments/1am2hh/is_it_really_possible_to_utilize_the_natural/
|
{
"a_id": [
"c8yn3s3"
],
"score": [
2
],
"text": [
"Well, first off, the disinfographic claims that there are electric currents in the ground, but in fact **the crust of the Earth doesn't have significant electric currents**, certainly nothing strong enough to extract useful power from. It's mostly incoherent babble that doesn't mean anything at all, so there aren't many actual claims to debunk.\n\nAlso, it says \"this is the secret they will do anything to hide\", but apparently \"they\" can't be bothered to use a handful of computers to initiate a sustained DOS attack against his shitty pseudoscience website and keep it offline.\n\nI gritted my teeth and went to that website, and was greeted by such headlines as \"A Chemical Conception of the Ether\" and \"Avenge Tesla Once and 4 All-- Elite Truth Warriors Only\" and \"Notes on a Hollow Earth\". This stuff is pure crackpot.\n"
]
}
|
[] |
[] |
[
[]
] |
||
5yuubs
|
why have salaries not increased on par with the cost of living.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5yuubs/eli5_why_have_salaries_not_increased_on_par_with/
|
{
"a_id": [
"det2acu"
],
"score": [
10
],
"text": [
"Our economy is based on an everlasting perpetual growth. In other words if company i.e. Walmart doesn't post profit increase in their year over year sales report it is considered unsuccessful or not profitable and investors start pulling away. One of the easiest ways to do that is to keep your payroll as low as possible. Now multiply that by 100s of powerful companies who are very powerful and and have significant representation and influence in our government and there is your answer. This is as simple way as I can put it without writing an essay."
]
}
|
[] |
[] |
[
[]
] |
||
eudqsl
|
Flairs, posters, lurkers, lend me your ears! I come to praise our NEW MOD!
|
She has already peered beyond the veil and trawled the deep dank underbelly of this subreddit- and I assure you, it's deep and it's dank!- and lived to [tell](_URL_0_) [the](_URL_1_) [tale](_URL_2_) (which you should definitely read, if you haven't already). Now, we're officially welcoming her to the Dark Side™ .
All hail the inimitable, indomitable and incredible u/SarahAGilbert- may the explorer and explicator of the mysterious ways of r/AskHistorians become its most gloried wielder of the modhammer!
Though we cannot pay her in mere gold and rubies, we can offer her the heady, intoxicating rush of banning neo-Nazis, purging threads of low-effort content, and addressing the question "why don't you have an 'Answered' tag?"
And so - as she studied, so now shall she be studied in turn, as she leaves the safe cocoon of the ivory tower and descends into the very depths of the internet. All hail u/SarahAGilbert \- scholar, scientist, moderator.
Pay your fealty below!
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/eudqsl/flairs_posters_lurkers_lend_me_your_ears_i_come/
|
{
"a_id": [
"ffoddbp",
"ffoef6q",
"ffoesob",
"ffojy23",
"ffol0v5",
"ffost8t",
"ffovyaj",
"ffp33uo"
],
"score": [
17,
26,
8,
6,
7,
17,
6,
7
],
"text": [
"Welcome to ~~best-paid~~ ~~most-respected~~ ~~most pleasant~~ ~~least stressful~~ ~~highest-status~~ a job on the internet!",
"Thank you so much for the warm welcome, u/hannahstohelit and the rest of the mod team! I'm excited to lend my hand in the effort to clean up the internet and let everyone know where all the comments have gone!",
"All hail the glorious ascendant /u/SarahAGilbert! Welcome to the storied and legendary ranks of the moderators, and long may you reign over this majestic community.",
"Gloria al nostro moderatore!!! May the stroke of your comment removals be fair and the swing of your banhammer be just!",
"Добро пожаловать в команду! Welcome, welcome, welcome!",
"On behalf of the lurking majority that come to read, thank you for sharing your insightful work, and thanks to all of you moderators for your stewardship. You've made it one of the most interesting and polite corners of the internet.",
"Welcome! Hals- und Beinbruch!",
"Welcome to our newest ~~slave~~ ~~unpaid intern~~ moderator! I hope you're ready for the massive influx of ~~wealth~~ ~~karma~~ interactions with neo-Nazis you'll be receiving."
]
}
|
[] |
[
"https://www.reddit.com/r/AskHistorians/comments/a3p1ig/meta_i_wrote_my_phd_dissertation_on_askhistorians/",
"https://www.reddit.com/r/AskHistorians/comments/a4yc1v/meta_i_wrote_my_phd_dissertation_on_askhistorians/",
"https://www.reddit.com/r/AskHistorians/comments/a5j123/meta_im_back_with_the_final_post_summarizing_my/"
] |
[
[],
[],
[],
[],
[],
[],
[],
[]
] |
|
31a5rw
|
What exactly happens when cake batter turns into fluffy, moist cake?
|
I don't understand the process that happens, or how sweet, battery goodness turns into fluffy goodness! :)
So what happens to batter when heat is applied?
|
askscience
|
http://www.reddit.com/r/askscience/comments/31a5rw/what_exactly_happens_when_cake_batter_turns_into/
|
{
"a_id": [
"cq0naa1",
"cq0u5zz"
],
"score": [
2,
2
],
"text": [
"Cake batter includes two chemicals, cream of tartar (or, to give it the chemist's name, tartaric acid) and baking soda (sodium bicarbonate). When mixed together dry, we call it 'baking powder', when sold mixed in with the flour, it becomes 'self-raising flour'. When mixed with water, these two chemicals react (slowly) to create salt and a gas, carbon dioxide. This causes bubbles in the batter. The first stages of baking help here, because, like most chemical reactions, it becomes faster at higher temperatures.\n\nThe batter contains some other chemicals too - mostly a protein, gluten, from the flour. As it cooks, different pieces (molecules) of gluten bind together, forming a strong framework. This traps the bubbles in place, making the light, fluffy, edible sponge that we call 'cake'.",
"There are several separate mechanisms that all produce the effect of getting bubbles of gas into the batter which the heat of baking 'sets' into a sponge-like structure. As mentioned above, yeast and baking powder both do this in different ways, yeast by the action of living organisms and baking powder from a chemical reaction to moisture.\n\nA third way to get the same result is used in sponge cake purely by the mechanical introduction of air into the mix prior to baking. Eggs and egg whites can be beaten until they are swollen with air bubbles and many times their original volume. This is them mixed with flour and sugar and the heat from baking makes the tiny bubbles expand and sets the mixture. A similar process works by 'fluffing' a dry mixture before baking by lifting and sprinkling the mixture to separate the particles of fat and flour and introduce air. This alone can have quite a strong effect of how much the final baked item swells during baking but care has to be taken whilst rolling and cutting (eg scones) to not compress the trapped air out of the dough.\n\nOther chemical mixtures are sometimes used such as soda (bicarbonate of soda) but this sometimes needs to be activated by an acidic liquid. Cream of tartar and bicarbe are sometimes used on their own, but I don't fully understand how they work without the other chemical to react with. Anyone know?"
]
}
|
[] |
[] |
[
[],
[]
] |
|
3svhtz
|
why aren't siblings born with the same dna?
|
Statistically speaking, non-twin siblings from the same parents could have the same DNA, right? Why doesn't this happen? What are the statistical odds that it could?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3svhtz/eli5_why_arent_siblings_born_with_the_same_dna/
|
{
"a_id": [
"cx0r1ce",
"cx0rb52"
],
"score": [
2,
2
],
"text": [
"You have 23 pairs of DNA in your body. One of each pair from your mom, another from your dad. This means you have about 0.5^23 chance of having the same DNA as a sibling, and that's not even factoring in recombination (bits of DNA switching around).",
"Not all of it. A child only contains half the DNA each parent has, with two parents combining to make a complete set. The best way to describe this is in terms of meiosis, the production of gametes (sex cells) in which the chromosome number (I am assuming you know basic Biology, if not ask questions) halves.\n\nSo, most humans have 46 chromosomes. These chromosomes are in pairs, with 23 pairs, each pair containing one from the mother and another from the father. Each chromosome in these pairs controls the same traits.\n\nSo, during meiosis, the chromosome pairs split apart into different cells to form sex cells. However the nature of this splitting is random, chromosome pair one could have the mother's chromosome go to one side, while chromosome pair two could have either the mother's or the father's chromosome to go to that side. This is called independent assortment, since all the chromosomes arrange themselves independently of other chromosomes (except the pair) This splitting is random, and generates 2^23 types of combinations for a single gamete to be produced, which is about 8 million. For the production of the two cells needed to make up a child, it is 8 million squared, or over 10 billion. Ten billion different combinations, and that is ignoring the other DNA randomization processes. Factor in the others, you get numbers in the trillions and quadrillions of combinations, and even though some are more likely to occur than others, the chance is still tiny that two siblings will be produced to be exactly the same in DNA."
]
}
|
[] |
[] |
[
[],
[]
] |
|
d326cy
|
how do computers transmit and translate video and pictures? does each picture get boiled down to a pixel level with a binary code for each pixel? what about video? it blows my mind that computers can do this.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/d326cy/eli5_how_do_computers_transmit_and_translate/
|
{
"a_id": [
"ezy7vre",
"ezyfb7w"
],
"score": [
3,
2
],
"text": [
"Every pixel has a colour represented by a binary code. Commonly a byte (8 bits) is used for each of the three primary colours of red, green, and blue, so you need three bytes (24-bits) per pixel. That gives 16 million possible different colours.\n\nPictures are then compressed which allows a big reduction in the number of bytes required. Pixels tend to be the same colour as adjoining pixels and encoding that in an image file allows it to be much smaller than if you described every pixel separately. Usually \"lossy\" compression is used which can allow the file to be much smaller, at the cost of not looking exactly the same as the original. There's a trade-off between file size and quality.\n\nVideo is just a sequence of pictures called frames. It can be compressed more because most frames are almost exactly the same as the previous frames. The compressor might only send one self-contained frame every second and the other frames are described based on how they're different from preceding and/or following frames. If one part of the frame is moving in front of the rest, the compressor can describe which parts of the frame have moved and how far, instead of having to resend the pixels.",
"Yes, in theory the computer takes each pixel gives it a number to describe its color and then goes on to the next, os that if you have a picture a hundred pixel by hundred pixel, you would transmit 10,000 numbers with a color for each pixel. The computer breaks up the color numbers into bytes for this. If you have only two colors like black and white you can fit 8 of those numbers into each byte, if you want 24-bit \"true color\" you end up needing 3 bytes for each pixel.\n\nThis is what happens with Bitmaps at least and some relatively rare forms of video.\n\nIn practice, pictures and videos like this can get really really big, so you use compression. This means that you don't transmit each single pixel, but use some math to describe where and when what color pixels are in a way that avoids unnecessary repetition. to shorten things a bit. The exact nature of the compression can differ from format to format.\n\nHowever it all boils down to the idea of giving each pixel a number that represents its color and transmitting a string of numbers that allows the computer to display pixels in the same (or at least a similar) way.\n\nThere are some exceptions however: vector graphics. These are not so much instructions to tell the computer what color each pixel looks like, but more instructions on how to draw the picture. It may contain an instruction like \"make a thin diagonal black line from the upper left corner to lower right corner of the picture\" and the computer has to figure out which pixels it has to make black itself."
]
}
|
[] |
[] |
[
[],
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||
3ras3t
|
why does taking (something) to the negative power give us 1/(something)?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3ras3t/eli5_why_does_taking_something_to_the_negative/
|
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"If you can realise that multiplication is the inverse of division, then it is pretty easy.\n\nFor positive powers:\n\n2^1 =1x2=2\n\n2^2 =1x2x2=4\n\n2^3 =1x2x2x2=8\n\nand so on. For a positive power, you multiply the number.\n\nA negative power has the same pattern, except with division, so:\n\n2^-1 =1/2\n\n2^-2 =1/2/2=1/4\n\n2^-3 =1/2/2/2=1/8\n\nand so on.",
"The fact that *a*^(-*n*) = 1/(*a*^(*n*)) is actually a matter of definition. However, any other definition would make little sense, and here's why:\n\nIf *a* is some number, the notation *a*^(2) is just a convenient way of writing *a*·*a*. In general, you have \n*a*^(2) = *a*·*a* \n*a*^(3) = *a*·*a*·*a* \n*a*^(4) = *a*·*a*·*a*·*a* \nand so on.\nThis is a definition we make: We define *a*^(*n*), where *n* is a positive whole number, to be *a*^(*n*) = *a*·*a*·*a*···*a*, where *a* occurs a total of *n* times in the product. (*a* can be any number, it doesn't have to be an integer.) In particular, this must mean that \n*a*^(1) = *a*.\nNow, consider something like *a*^(3)·*a*^(5). We know that *a*^(3) = *a*·*a*·*a* and *a*^(5) = *a*·*a*·*a*·*a*·*a*, so \n*a*^(3)·*a*^(5) = *a*·*a*·*a* · *a*·*a*·*a*·*a*·*a* = *a*^(8) (=*a*^(3+5)). \nSimilarly, \n*a*^(7)·*a*^(2) = *a*·*a*·*a*·*a*·*a*·*a*·*a* · *a*·*a* = *a*^(9) (=*a*^(7+2)). \nAs you can hopefully see, if *n* and *m* are positive whole numbers and you multiply *a*^(*n*) by *a*^(*m*), you'll end up with *n*+*m* factors *a* and so the result is *a*^(*n*+*m*). This is a rule we've thus proven (kind of proven anyway) for positive whole numbers: \n**RULE**: *a*^(*n*)·*a*^(*m*) = *a*^(*n*+*m*)\n\nNow, what should *a*^(0) be? We *could* define it to be whatever we feel like, but it's best to try to make the definition as convenient as possible, so why not try to define it to follow our rule *a*^(*n*)·*a*^(*m*) = *a*^(*n*+*m*)? Well if it is to abide by the rule, we need to have \n*a*^(*n*)·*a*^(0) = *a*^(*n*+0) = *a*^(*n*). \nThis actually means that we must have \n*a*^(0)=1 \nfor our rule to keep holding if *n* or *m* is zero. (Since *a*^(*n*)·*a*^(0) = *a*^(*n*) can only be true if *a*^(0)=1.)\n\nFinally, let's move on to negative whole numbers. Again, we *could* define things in a lot of ways, but again, we insist that our rule for exponents should remain valid for negative integers too. This means that we must have \n*a*^(*n*)·*a*^(-*n*) = *a*^*n*+(-*n*) = *a*^(0) = 1. \nAt this point you can divide through by *a*^(*n*) on both sides and you end up with \n*a*^(-*n*) = 1/(*a*^(*n*)). \n\nSo in other words: If you want the rule *a*^(*n*)·*a*^(*m*) = *a*^(*n*+*m*) to be true for all whole numbers (and not just the positive ones) you must have *a*(0) = 1 and *a*^(-*n*) = 1/(*a*^(*n*)).\n\nA couple of remarks: \n*0*^(-*n*) is not defined (unless *n* itself is negative). This is because the equation *a*^(*n*)·*a*^(-*n*) = 1 becomes 0^(*n*)·0^(-*n*) = 0·0^(-*n*) = 1 if *a*=0, and that's absurd. There's just nothing you can multiply by zero to get one. Sure, we could define 0^(-*n*) to be something else, but doing so would then break the rule we've tried to adapt to. \nI've only discussed whole numbers. If you want to consider rational numbers (fractions of whole numbers) or real numbers (any number that can be represented with decimals) as powers, the same argument still applies; it's just a little harder to define *a*^(*x*) when *x* is no longer an integer. (For instance, what would *a*^(√2) or *a*^(π) mean?) However, as soon as you do define *a*^(*x*), you still want it to fit the rule we established and so the same argument will lead to *a*^(-*x*) = 1/(*a*^(*x*)).\n\n**Summary:** For positive whole numbers *n* and *m* it's true that *a*^(*n*)·*a*^(*m*) = *a*^(*n*+*m*). If you want that to remain true for all whole numbers it needs to be true that *a*^(*n*)·*a*^(-*n*) = *a*^(*n*-*n*)=*a*^(0)=1, so *a*^(-*n*) = 1/(*a*^(*n*)). Just defining what *a*^(*x*) means for rational or real numbers *x* in general is pretty cumbersome, but the same argument goes through as soon as you do."
]
}
|
[] |
[] |
[
[],
[]
] |
||
qyolp
|
the annoying sound in my ears when i get out of the shower.
|
Not just the feeling of water in your ears (which goes away hitting your head with your hand on the area over your ear leaned to the side) but, you know, that sound. It's like there was a little, tiny flag in your ear which would wave very strongly with every move you make with your head.
And optional: How to get rid of it?
This time it's really extreme and it won't go away. It will drive me CRAZY!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/qyolp/eli5_the_annoying_sound_in_my_ears_when_i_get_out/
|
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" > It's like there was a little, tiny flag in your ear which would wave very strongly with every move you make with your head.\n\nIf it's a clicking sound and seems related to swallowing, yawning, or breathing, you may want to ask a doctor about possible [Eustachian tube](_URL_1_) problems. That's a little tube inside your head that helps you \"pop\" your ears and equalize pressure.\n\nIf you mean some sort of ringing sound, then I'd suggest you look at [ELI5 : Tinnitus](_URL_0_)."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/explainlikeimfive/comments/o7bq6/eli5_tinnitus/",
"http://en.wikipedia.org/wiki/Eustachian_tube"
]
] |
|
52b4r1
|
Can a collapsing star have such great mass that the black hole formed completely absorbs the supernova and the star simply "goes dark?"
|
askscience
|
https://www.reddit.com/r/askscience/comments/52b4r1/can_a_collapsing_star_have_such_great_mass_that/
|
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"Yes, but it is not really due to the size of the star (given that the star is massive enough to undergo core collapse).\n\nOnce nucleosynthesis in the core of a star reaches iron-56, it begins to consume energy, rather than create it. If the core is large enough, electron degeneracy won't be able to support the core against the force of gravity and it will collapse catastrophically. During this process, a great deal of the gravitational potential energy is transferred to material that has \"rebounded\" from the core, which accelerates it away from the core. How exactly this happens is not understood at this time. \n\nWhat we do know is that in some cases the amount of energy transferred is enough to expel most of the outer layers of the star in a supernova. In others, so much energy is transferred that the star is completely destroyed, and no remnant black hole or white dwarf is left behind. In other cases, the energy transferred is not sufficient to push the outer layers to escape velocity and no supernova is observable. \n\n[Here](_URL_0_) under Current Models, Core Collapse is a nice chart giving a general overview of size/properties, type of supernova and remnant. "
]
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[] |
[] |
[
[
"https://en.m.wikipedia.org/wiki/Supernova"
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||
ax54wr
|
How do white bloodcells know what to attack?
|
I mean do they have a tiny brain? They just attack everything? And the same goes for platelets.
|
askscience
|
https://www.reddit.com/r/askscience/comments/ax54wr/how_do_white_bloodcells_know_what_to_attack/
|
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"This is a fantastic question! Though, I will preface this answer with 1) it is extraordinarily complex and we are still learning so very much about the intricacies and signaling pathways the many different types of white blood cells use to recognize \"self\" from \"not self\" and how they attack, 2) I am just a lowly surgeon, not an immunologist so I may make some small mistakes that I would hope my Allergy and Immunology colleagues get expand upon, and 3) I'm going to try to make this as simple as possible so please ask more questions if you'd like clarification or more information on anything else I touch on!\n\n & #x200B;\n\nFirst, lets look into what is a white blood cell. In the bone marrow, pluripotent stem cells are constantly replicating and differentiating. What this means is a constant population of stem cells that have the ability to become a whole host of different types of cells in the blood are living in the bone marrow waiting for specific signals that tell them the body needs a certain type of cell now be it red blood cells, platelets (in the form of megakaryocytes), B-lymphocytes, neutrophils, eosinophils, etc. I won't go into the signaling pathways for the differentiation of the stem cells but there are some factors that act on the bone marrow, that we have been able to synthetically create too, like G-CSF (granulocyte colony stimulating factor) that we can give to patients with cancer or other types of diseases that reduce the number of granulocytes (a specific type of immune cell) that help increase their white blood cell count!\n\n & #x200B;\n\nWhen it comes to immunity and infection, there are two different pathways that the body fights infection. The first is the innate immune system. This system is endogenous, non-cellular mechanisms that help fight infections. This includes things called \"complement\" which is a series of proteins that basically cover an antigen (something that activates immune cells) and can start to destroy it itself and things called immunoglobulins which can cover and mark an antigen to be recognized by immune cells to be destroyed. The innate immune system also encompasses other functions but that is a little too specific for your question so I'll not go into detail unless asked later.\n\n & #x200B;\n\nYou also have the cellular immune system which encompasses all the different types of immune cells. These include, but are not limited to, lymphocytes (\"T\" and \"B\" cells), leukocytes (macrophages, neutrophils, eosinophils, basophils, etc.), APCs (antigen presenting cells such as dendritic cells), plasma cells (activated B cells), natural killer cells ... the list goes on. This part of the immune system is the cellular arm and each population of cells within this system has specific jobs. Neutrophils can be considered the workhorse and first line of defense against pathogens. Let's say you get a splinter in your finger and some bacteria is introduced into the dermis and starts a local infection. The cells where this infection is occuring will upregulate an enzyme known as cyclooxygenase and start to produce a type of molecule called prostaglandins. These start the inflammatory process. Inflammation is defined as the process by which rubor, tumor, calor, dolor, and loss of function occur -- redness, swelling, warmth, and pain. These prostaglandins, as well as other inflammatory signals, are released into the dermis and causes upregulation (increased production) of other proteins but for this example it upregulates these little proteins that can line the inside of the vasculature that can help neutrophils grab, roll, and eventually stop on the vascular wall. There is a whole bunch of them and some are called selectins, integrins, and other CAMs. When these proteins are upregulated, the chances of passing neutrophils coming into contact with them increases. This process is called margination, rolling, adherence, and diapedesis. Once a neutrophil is stopped on the vascular wall surface in the area of inflammation, neutrophils rely on chemotaxis (sensing of inflammatory mediators) and follows this \"trail\" of inflammation to the source -- the infection. Once there, they are activated and essentially kamikaze themselves against the bacteria. We know this process colloquially as \"pus.\" Pus is just a giant mess of activated, dead neutrophils. This further increases the inflammatory process and more and more white blood cells are recruited.\n\nIn addition to neutrophils, macrophages diapedesis through a similar method as neutrohils into the tissue where inflammation is occurring, and utilizing chemotaxis, can encompass a bacteria and engulf it. Once engulfed, the macrophage will release harmful enzymes that help \"kill\" bacteria or whatever pathogen is causing the infection. They also release a whole mess of inflammatory mediators called interleukins. There are many interleukins and they activate other responses in the body in a very sophisticated but complex way that I do not trust my own knowledge of in fear of making some grave mistakes. I also think that this is way above the level of detail you would like but I'll say it's extremely interesting but incredibly complex with active research in this area still occurring!\n\n & #x200B;\n\nThis would not be a good answer if I did not talk about lymphocytes. These are my personal favorite population of immune cells. These come in two flavors, \"T\" and \"B\" cells. Before my immunologist friends get their pitchforks out, I know NK cells are considered lymphocytes but I do not feel comfortable enough discussing their role in depth as it's been many years since I took I & I. First, let's talk about T cells cause I think they are very cool. \"T\" cells stands for \"thymocytes\" because they grow and mature in the thymus. When we are developing, T cells migrate from the bone marrow to the thymus where they undergo a very rigorous process called tolerance. Tolerance is a system of checkpoints that all T cells must pass that says each cell understands what \"self\" is and what \"not-self\" is. I believe up to 98% of T cells fail tolerance and are destroyed once they fail. Tolerance is a two step process where first positive and then negative selection occurs. Positive selection is a check to make sure T cells can interact with a very important cell surface protein called MHC (major histone compatibility complex). Almost all cells in the body express MHC however there are two classes of them, MHC-I and MHC-II. All T-cells must be able to interact with MHC and if it cannot, it is signaled for apoptosis (signaled, controlled cell death). If the T cell interacts with MHC I then the T cell is further differentiated to a CD8+ (\"Cytotoxic\") T cell and if the T cell interacts with MHC-II it differentiates to a CD4+ (\"Helper\") T cell. Next is negative selection where the T cell must be able to recognize \"self\" and to not activate to \"self.\" If a T cell strongly interacts with it's corresponding MHC protein (CD8+ with MHC-I and CD4+ with MHC-II) then the T cell is marked for apoptosis because it is reacting to strongly to \"self\" and can cause unchecked damage to our own body. Negative selection wants T cells that weakly interact with MHC so that it will check MHCs in comes into contact with but will only strongly interact with MHCs from other organisms, not \"self\" MHCs. Then these cells are released into the blood stream and start their life checking MHC throughout the body looking for \"not self\" to become activated and signal whatever it is recognizing as \"not self\" for destruction.\n\n & #x200B;\n\nB cells mature in the bone marrow hence why they are called \"B\" cells. These cells have a really cool receptor called \"B cell receptor\" or BCR that rearranges its gene so many times that it can produce 3x10^(11) different combinations! That is an insane number of different, specific combinations that the BCR can recognize and cause B cell activation! It boggles my mind how incredibly adapted at recognizing ANYTHING the B cells are! Anyways, once the BCR is developed and the B cell enters circulation, it will become activated by either another activated B cell or by a CD4+ \"Helper\" T cell. Once activated within a lymphoid tissue (Spleen or lymph node) the activated B cell turns into either a plasma cell or a memory B cell and starts producing tons and tons of immunoglobulins (IgM and IgG) that stick to the antigen (bacteria, fungus, virus, whatever) that initially activated the B cell and marks it for destruction.\n\n & #x200B;\n\nI hope this was informative and answered all questions you had. If you'd like clarification or more information please don't hesitate to ask! I wanted to touch on a lot of things but the simple answer to your question is these cells \"sense\" chemical signals produced by the antigen (\"not self\") thing in the body and either directly kill it or tag it with chemicals that allow other cells to notice it and kill it.\n\n & #x200B;\n\nAlso I just noticed what you said about platelets. Platelets are NOT immune cells. In fact, platelets come from very large cells called Megakaryocytes and deal with coagulation (the bodies ability to make blood change from a liquid to a solid). If you'd like more information about that let me know and I'd be happy to give you a crash course in coagulation!"
]
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3kh1hm
|
the difference between deductive and abductive reasoning.
|
_URL_0_
I was watching an episode of QI and they mentioned that Sherlock Holmes did not use deductive reasoning. He used abductive reasoning. I tried to learn the difference, but I go crosseyed every time I read the above article. To quote Richard B. Riddick: "Maybe you should pretend like you're talkin' to someone educated in the penal system. In fact, don't pretend."
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3kh1hm/eli5_the_difference_between_deductive_and/
|
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"It simply means coming up with ideas to explain things we see. Those ideas then are put to the test and discarded or validated.\n\n- Deduction: Winter is cold. Winter starts next month. So it will be cold next month. \n- Induction: Last winter was cold, the one before was cold, and so on. So next winter is probably going to be cold. \n- Abduction: Why is it so cold? Well, if it were winter, then of course it would be cold. So it's probably winter.",
"Deductive reasoning is deducing or \"arriving at\" a conclusion based on a clear observation that can be connected and make logical sense. (More so evidence based)\n\n(Ex: If its raining outside and I don't bring an umbrella, then I will get wet)\n\nAbductive reasoning bases a conclusion off a set of incomplete observations. The conclusion is reached when a decision is made on the data that you currently have. (More so judgement based)\n\n(Ex: I may or may not be raining..I'm not sure. So I will take my umbrella. If it is then raining I will not get wet)",
"* Deductive reasoning is all about if A is true, then B must be true. It is often less useful in the real world, as things are seldom that certain.\n* Inductive reasons is the voice of experience...yesterday it was cloudy, then it rain...today is cloudy, so it will likely rain again. Induction is more about probability than certainty.\n* Abduction is about observing anomalies, and finding a common explanation for those anomalies. That is what Holmes is doing when he determines the killer is a left handed smoker who spend time in the tropics. He is picking out details and finding the simplest explanation that ties them together."
]
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[] |
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"https://en.wikipedia.org/wiki/Abductive_reasoning#Deduction.2C_induction.2C_and_abduction"
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7uhefy
|
How realistic is the cancer "vaccine" talked about recently?
|
A recent post to /r/worldnews is talking about a cancer "vaccine" talked about in this [article](_URL_0_).
All sorts of claims have been made about cancer in the post. So, how realistic is this?
|
askscience
|
https://www.reddit.com/r/askscience/comments/7uhefy/how_realistic_is_the_cancer_vaccine_talked_about/
|
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"Paper is available in its entirety here: \n[**Eradication of spontaneous malignancy by local immunotherapy**\n Idit Sagiv-Barfi, Debra K. Czerwinski, Shoshana Levy, Israt S. Alam, Aaron T. Mayer, Sanjiv S. Gambhir, Ronald Levy - *Science Translational Medicine*](_URL_0_)\n",
"So, immunotherapy has long been seen as a holy grail for cancer treatment. The immune system is naturally programmed to attack cells that have gone a bit weird (to use the scientific term). The problem tends to be that the cancer cells can also alter themselves so that they are disguised from the immune system, or in fact inhibit any immune cells that come into contact with them. This stops the immune system from seeing them as dangerous, allowing the cancer to grow. So the balance of the immune response is in favour of leaving the cancer alone.\n\nWhat this treatment does is inject the tumour with molecules that tell the immune cells in the vicinity of the tumour to wake up and start doing their job, overcoming the inhibition that the cancer cells have put in place. This means that the balance of the immune response is now to attack the tumour, which seems to work very well.\n\nThe really cool thing is that now that the immune system is trained to see the tumour as bad, and will attack similar cells in different sites. This is why it behaves in some fashion like a vaccine.\n\nIt's perfectly viable, and very exciting. As always, there is always the question of how well it translates into human biology but it is still very promising. I think one problem is going to be how specific the immune response is. In the paper, they see the immune cells are trained to attack cells with protein markers unique to the tumour cells, which is a good sign. One concern might be that if you accidentally trigger the immune response to normal cell markers, it could cause your immune system to attack healthy cells which would obviously be a very bad consequence. Another would be how readily a tumour can evolve to overcome the immune system attack. If the immune system only ends up going for certain markers, it could miss tumour cells that don't have the same ones. These could then continue to grow and cause the cancer to return.\n\nETA: thank you kind, golden stranger!\n\n...strangers!",
"It's actually a really cool concept that frankesteins together mechanisms of action that we already use.\n\n1. Making cancer cells visible to the immune system: PD-1 and PD-L1 inhibitors\n\n2. Siccing T-cells on cancer: CAR-T cells, Allogenous stem cell transplantation, BiTE immunotherapy\n\nThey then do this only locally, circumventing the problems that would arise if we did it systemically, i.e. death from immune system overdrive.\n\nI'm interested in seeing how well it works in humans and reading about it made me slightly nervous about my job to be honest",
"Veterinarians have been using cancer vaccines for a while. The melanoma vaccine has about a 50% success rate which is pretty good considering how melanoma is so difficult to treat. There is also a fibrosarcoma and B cell lymphoma vaccine. As far as I know those vaccines are less effective. Fibrosarcoma in cats is extremely aggressive while lymphoma is more manageable with chemo. The vaccines are all made by Merial. UPenn Vet and The Children’s hospital in Philadelphia have had some instances of curing children’s leukemia with immunotherapy but those cases were experimental. ",
"There is a treatment for stage 4 brain cancer that does this indirectly. Duke has modified the polio virus to attack cancer cells, and they inject it into the center of a brain tumor. While the polio virus is attacking the cells, the immune system starts going in to clean up the mess. In turn, the immune system learns to recognize the cancer cells. The whole process seems to last for months after just the one single injection.\n\nYou can google PVS-RIPO for further information. The first few patients were treated in 2012-2013 and some are still alive without any further treatment. Those patients had recurrent Glioblastoma Multiforme, which is perhaps the deadliest cancer situation that one can imagine.\n\nWhile this would technically be considered virotherapy, the immune system plays a huge role in the outcome.\n\nThey are now in phase 2 trials, and still only for brain tumors, but I believe the assumption is that it could be widely used among many different solid tumors in the future.",
"I work in this field. \n\nThis type of cancer vaccine is kinda old news. What's really cutting edge are the personalized cancer vaccines based on mRNA that are in clinical trails in humans **already**. Basically, these vaccines are tailored to an individual's cancer. You see, your cancer and my cancer may have the same name, lymphoma for example, but they may be very different in terms of their susceptibility to drugs and especially to vaccines. Using personal genomics to tailor mRNA to program your own cells to make a vaccine against your very unique form of cancer is the real key to all of this. Adding on top of this is that mRNA is just a superior way to produce vaccines. As it turns out, when your body makes the vaccine inside its own cells, it stimulates your immune system more effectively than a vaccine made in a factory and injected (this has to do with MHC1 and MHC2 activation). \n\nThese clinical trials are looking promising. If they work, this can be combined with checkpoint inhibitors and other mRNA therapies (that also boost immune response against cancer) and it's bye-bye cancer. \n\nLet's just say that it's the most promising thing I've seen in cancer therapy ever. ",
"To make a broad analogy:\n\nPicture your car for a moment. Immunooncology broadly speaking unlocks parts of the immune system that keep the body from attacking itself. In our analogy immunooncology released the parking brake and the car is in neutral. Certain combination treatments are the equivalent of giving a push.\n\nWhat happens next depends on how your car is parked. \"Curing\" Murine models of cancer are the relative equivalent to parking on a steep hill and popping bottles of champagne when the car rolls downhill. It's dishonest at best to promote the results that way and a bit laughable, but academia does it periodically to stir public interest (and by proxy send public funding their way).\n\nTo continue the analogy most human cancers are the equivalent of parking on a level surface at the base of a hill. Unlocking the parking brake is important, but it's not usually going to send you uphill. Sometimes you get lucky and the metaphorical car wants to move, meaning you only need to give a small push to get the car unstuck and it climbs under it's own power (a so-called \"hot\" tumor) but more often than not you're talking about pushing a car uphill by hand, which isn't terribly effective.",
"Having read a bit of the responses, I have to ask: Given the cancer cells ability to \"blend in\", would this treatment possibly cause the body to attack it's healthy cells? If so, how would it be remedied and how often would this occur?",
"Have we seen similar successful results in test on mice etc, that sadly haven't panned out successfully for humans in the end in the past? \nJust wondering if this is the first time we've seen such a positive success, or if we should still be somewhat apprehensive? ",
"So I worked on a project and helped publish a paper that also showed this exact effect (even showing it attacked tumors in other locations) several years ago (PMID: 25179345).\n\nOne of the biggest issues with directly translating this to therapy is that directly injecting a vaccine into a tumor cell is not necessarily a wise choice and not commonly done (I think, my clinical exposure to oncology isn't large). The main fear is something called \"tumor seeding\", which can also happen when they aspirate or biopsy, or do something otherwise invasive with a tumor that could cause cancer cells to dislodge and make it to the blood or lymphatic systems. If the tumor is well-demarcated (ie. enclosed), you don't want to open up a channel to your blood supply for cancer cells to spread throughout your body (hematogenous spread). Clinically the chance of this is probably very low and this is a consideration when physicians consider how to biopsy a tumor, but if you start making it standard procedure, who knows what could happen. \n\nEven if the cancer is metastatic, it is possible that it's in a compartment that is very well isolated from the rest of your body. For example when testicular cancer is suspected, a biopsy is almost never performed and the suspected testicle is straight up removed because it's in a very well-enclosed portion of the body (referring not to the skin scrotum, but another membrane separating it from the inside of your body). ",
"As scientists we're equally sceptical of new wondrous drugs, but I can tell you that immunotherapy is the most exciting development in cancer therapy in decades. Maybe the one thing to keep in mind is that it tends to work much better in certain cancers (e. g. melanoma) than others. Source: PhD in Molecular Biology working in cancer research",
"Can I ask a follow up question? How long will it be until we get first results from the clinical trials?\n\nThis seems so promising, that I'd love to stay up to date on current progress, can anyone tell me where I should check?",
"There are many very promising developments, but one must remember that cancer isn't a single disease, it's a whole group of related diseases, which are very different. So, it might work on some types, but not others. Also, from doing it in a lab until its a useable tool in clinical use might be decades.\n\nAs for the vaccine effect, don't forget that cancer is based on random mutations, so there is no guarantee that \"defense knowledge\" from one immune system is transferable to another patient, with a slightly different \"enemy\".\n\nDon't expect a silver bullet for all cancers. I think a more reasonable expectation is that it (or something like it) will become another tool in the existing toolbox for fighting cancer, and used in combination with other tools, much like how we today mix surgery, different kinds of chemo and radiation therapy in different ways, depending on the exact nature of each case.\n\nAs much as I would like to see a silver bullet, I don't think it's realistic to expect. On the bright side, though, we are getting much better at treating, and the advances are done at an amazing pace.",
"As a general rule, one should be very cautious about translating results from mice into humans.\n\nA great example is avastin/bevacizumab (an anti-angiogenesis antibody). When early studies of endostatin (an anti-angiogenesis molecule) performed very well, Time magazine printed a cover along the lines of \"A Cure for Cancer\". \n\nIn retrospect, people in the field admit that it should have read \"A Cure for Cancer in Mice.\"\n\nThere are many issues with mouse models, not least of which is that cell lines are often the source of the \"tumours\" (such that they differ dramatically from tumours that arise spontaneously in humans.\n\nThis study accounted for that somewhat. They did some of their experiments with cancer cell lines injected into mice, and some with mice that spontaneously develop tumours. Even the latter have to be taken with caution, though, as these are still derived from modified cells that express a specific tumour-inducing viral protein. (All the cells in these mice have the gene for this protein and they develop breast tumours.)\n\nFinally, immunotherapy has been an amazing step forward and, along with targeted therapies like monoclonal antibodies (which are used in immunotherapy) and small molecule kinase inhibitors, represents the biggest advance in the past 20 years. \n\nSo the strategy is promising and it is aligned with what has been working over the past few years. Too early to say how it will work in humans.\n\nHere's an [article](_URL_0_) on some previous stumbles.",
"OK I've read the paper and it's very promising, but here are some caveats:\n\n-nearly all of the tumors were treated at a very small size (a completely standard practice in the field). It's unclear how well this would work in a patient with heavy tumor burden.\n\n-all of the injected tumors were at the surface and readily \"injectable\". It's not clear if this would translate well in a situation where all tumors were internal.\n\n-all the recent successful immunotherapies don't work as well in tumors with a low mutation burden (which is most solid tumors), because fewer mutant proteins = fewer immune targets = lower immune stimulation. The models used here are fairly immune-stimulating, so may be a bit overestimating. That being said, the broad results are still unprecedented and exciting.",
"TL;DR. Immunotherapy uses monoclonal antibodies which serves to block inhibitory pathways tumour cells might utilize to halt the immune response. This works best on tumours with high mutation rates, \"hot\" tumours, essentially making them appear as foreign to our immune system and illicit a response. Other tumours have low mutation rates, \"cold\" tumours, which appear almost identical to our own cells and therefore wouldn't traditionally trigger the immune response. Using antibodies inhibits the inhibitory pathway, effectively activating the immune response. This therapy, although promising, is very toxic and expensive. Altogether, this is a very promising avenue in cancer treatments moving forward\n\n\nCancer vaccines, a.k.a immunotherapy, is a remarkably vast and exciting field of oncology. In general, immunotherapy serves to educate our immune cells, namely our B and T adaptive lymphocytes, to recognize and kill tumour cells. Tumour cells are smart and will develop mutations to prevent them from being recognized and consequently killed by our immune cells. Tumour cells have learned to up-regulate specific proteins, called checkpoint inhibitors. Checkpoint inhibitors are normally expressed on immune regulatory cells, which when bound to ligands on activated CD4 and CD8 cells, halt their activation and \"shut\" them down. Tumour cells expressing these checkpoint inhibitors, namely PD-1, can effectively inhibit the attack from CD8 cells that may recognize the tumour as foreign. Tumour cells also can secrete various cytokines in the microenvironment, such as TGF-B and IL-10, which can also inhibit the activation of CD4 and CD8 cells, as well as boosting the activity of regulatory T cells which can exert similar effects.\n\nImmunotherapy works by using humanized monoclonal antibodies that when bound to checkpoint inhibitor proteins prevent their binding to its complementary ligand. This means you are inhibiting the inhibitory pathway, which ultimately leads to an activation of CD4 and CD8 T cells that recognize the tumour as foreign. Now, that is the major caveat of immunotherapy. The CD4 and CD8 T cells MUST recognize the cancer as foreign. \"Hot\" tumours are tumours with high mutation rates and therefore generate neo-antigens quite frequently. A model \"hot\" tumour is melanoma, whose high mutation rates are as a result of constant exposure to harmful UV radiation from the sun directly. Tumours that generate new antigens frequently increase the likelihood our CD4 and CD8 cells will have receptors that recognize this as foreign. \"Cold\" tumours on the other hand have low somatic mutation rates and do not generate neo-antigens as frequent as their \"hot\" counterparts. Therefore, our CD4 and CD8 cells are much less likely to recognize the tumour cells as foreign and the tumour persists. Keep in mind, tumours cells are just really messed up versions of our own cells. We have mechanisms to prevent our immune cells from attacking our own cells (autoimmunity). Cancer cells with low mutation rates look identical to our own cells, which would not typically illicit an immune response.\n\nAnother avenue recently taken is the use of oncolytic viruses as part coupled with monoclonal antibody therapy. Oncolytic viruses prefer to infect tumour cells as tumour cells represent the perfect host; they do not undergo programmed cell death, they do not alert the immune system and most importantly, are always dividing and replicating their DNA which the virus needs to survive. Oncolytic viruses, even with broad tropisms, will preferably infect cancer cells over normal healthy cells. When the virus completes a round of replication, it will lyse the cancer cells, releasing internal antigens that can stimulate the adaptive immune response, as well as danger molecules such as ATP. Danger molecules like ATP are powerful inducers of the immune response and can very quickly establish local inflammation in the tumour microenvironment, which is necessary to allow trafficking of the appropriate immune cells. Danger molecules essentially are the ticket for the immune cells to get into the tumour site. Monoclonal antibodies can remove any checkpoint inhibition the activated lymphocytes may encounter to kill the tumour cells. This has been shown to work extremely well, and even better, offers excellent chances for long term remission (memory effect of the immune system).\n\nUnfortunately, monoclonal antibody therapies act non-specifically and therefore can be incredibly toxic. Almost anyone that is enlisted on monoclonal antibody regimens for immunotherapy experience some adverse side effects. Unfortunately many must pull off treatment altogether. Also, there is a major cost issue especially in countries with private health care. Ipilimumab, a monoclonal antibody that blocks the CTLA-4/B-7 interaction, costs around $700 000 annually. Unfortunately, most people just can not afford this treatment even though it works.\n\nIn my opinion, this is the poster child of current cancer treatments. It is one of the only treatment regimens that attempts to \"personalize\" the treatment as much as possible and its ability to offer long term remission is extremely promising.",
"Cancer vaccines are totally a real thing. Well, they're actually a couple different real things.\n\nThe first is vaccines like Gardasil (human papillomavirus), where the vaccine is **actually against a virus that causes cancer**. These are pretty normal vaccines. \n\nHowever, there is also a concept of cancer vaccines against \"neo-antigens.\" As cancer cells accumulate mutations, they begin to display mutant proteins on their cell surface. If we can identify these proteins, and create a platform to command cells to create antibody responses against them, we can program the immune system to seek out cancer and destroy it. This idea has worked in a variety of different animal models of cancer, from a variety of different groups, in a variety of different ways, which convinces me that the underlying technology is valid, and it's a question of when, not if, we see clinical advancement. \n\nChimeric antigen receptor T cell therapy (CAR-T cell therapy) is a closely related technology where the T-cell programming is done outside the body rather than with a vaccine. It's very promising and even has an FDA approval at this point (Gilead/Kite's ~~Keytruda~~ Yescarta). We're talking cancer *cures* for cancers that were previously universally near fatal. Side effects and especially runaway T-cell proliferation can still be a problem. \n\nWatch this space. Scientists are seriously starting to crack this nut wide open, between new immunotherapy regimes (targeting PD-L1 and/or CTLA-4), programmed CAR-T cell therapy, and cancer vaccines. We're starting to understand how traditional cytotoxic chemotherapy drugs may work in conjuction with immuno-therapies, and we're starting to understand the interplay between these systems previously thought to be disconnected. We really are on the cusp of a real revolution, and I'm usually an intractable cynic about most cancer therapies. \n\nEdit: got a brand name wrong. It's Yescarta. Keytruda is a monoclonal antibody immunotherapy targeting PD-L1. Five years out, it's 8x more patients are alive and cancer free (40%) than the previous treatment (5%). ",
"Im going to re-post my comment from r/world news, and make minor edits for spelling and clarity. It seems I have a more cynical perspective than some here. My background is that I am an immunologist working for a biotech company developing cancer immunotherapy drugs. \n\nMy previous post:\n\n“I work in this field and although this is a nice approach (CpG will do a lot of good stuff beyond just driving OX40 and I think it’s a nice combo) there are big limitations here. The real issue is that this relies on pre-existing T cell infiltration. This is one of the big challenges for immunotherapy as a whole: in the clinic so far, it has mostly been effective in patients where there is already an immune response against the tumor and where there are already infiltrating T cells specific for a tumor antigen (this is mostly pertaining to solid tumors, liquid tumors are another matter and are looking very promising with CAR-T therapy). Patients that do not have that infiltrate tend not to respond to these therapies, which is why current approved immunotherapies like PD-1 blockade only work in about 10-20% of patients (although those numbers do get better when you combine it with other agents, like IDO inhibitors or CTLA-4 blockade), and only in tumors like melanoma or MSI high colorectal where there is a high mutational load in the cancer, meaning that there are a lot of tumor neoantigens that can serve as targets for a productive immune response. Essentially, for the approach described to work, you need the patients tumor to have a good antigen that the immune system has recognized, and that limits you to a subset of cancers, within which the drug will still probably be partially effective because some of those patients may need other combination therapies to reduce immunosuppressive factors that would shut down that T cell response (although hopefully the CpG will help with that by aggravating the immune system in general).\n\nAlso, even in a scenario where you have an antigen, it may still not work. The reason for this is that although you may get a T cell that can recognize that antigen, if that antigen is a self antigen (for example, something normally expressed during pre-natal development that is now being overexpressed by the tumor) there is a good chance that the T cell which recognizes it will not have a high affinity TCR, unlike T cells which recognize completely foreign antigen in the context of an immune response to a pathogen, for example. That means that you’ll get a weak T cell response, so you’ll get the infiltration and some level of parmacodynamic response, but weak efficacy. The fact that this works in mice is nice but the problem is that a lot of these mouse tumor models have good antigens in them that allow for these responses. So you may be modeling under ideal circumstances that don’t reflect the reality of the majority of human cancer patients, in terms of antigen exposure. \n\nThis has been a fundamental limitation of cancer vaccines as a class of therapeutic. There are A LOT of examples of cancer vaccines that went to the clinic, went into patients, resulted in a T cell response against the particular tumor antigen, and ultimately provided very little benefit to patients because those T cells weren’t effective at killing the tumor. So if this approach is successful at taking a T cell specific for self antigen being expressed abnormally in the cancer (like most prostate cancers, for example) or for a neoantigen resulting from a mutation that causes a new epitope to form, and then driving that T cell to a more activated and effective state via OX40, that could be effective at solving the cancer vaccine challenge, but we’ll have to wait and see.”",
"A lot of my published research was on Cancer therapeutics, so this topic is something I know quite a lot about. \"Killing cancer cells\" is not a hard process. We have been able to do this for a long time. The issue comes with therapeutics want to in some way kill the cancer cells, keep killing them, all while not hurting the person. The last part is the hard part, because we really haven't found a good way to do that yet. Most cancer treatments end up doing more harm to the person. I don't want to dampen any hopes on on this, but we hear about \"the cancer vaccine\" or that we can finally \"kill cancer cells with a drug\" and then we hear nothing about it in the future. That is because we can't find a way to safely administer these treatments since they always end up doing damage to the point of not being useful. Also, even if we do find something that works in the lab, it may very well not work as well with humans. Going from successful lab research to a treatment that can be used for the public can take an extremely long time, and for good reason. They want to make sure they aren't shotgunning out a therapeutic that will end up harming most that take it. With all of that said, I am very optimistic on where we are regarding cancer research. While we aren't quite there yet contrary to what these recent articles may say, we are still somewhat close. The problem is that we have been somewhat close for a while, but getting us over that last little edge is the hardest part. ",
"Immune therapy isn't new. It works wonders in theory and for limited times has near-miraculous results in practice. Similar clinical trials have already been done, achieving similar results for a limited period of time. Problem is the mouse model in the paper is very simplistic -- a flaw for most (all?) tumor mouse models. Real stage IV nasty cancers that we have a hard time curing usually have genetic instability and *extreme population variance* that is somewhere between extremely difficult and impossible to simulate in a laboratory. Real advanced cancerous tumor cells tend to adapt to cancer \"vaccines\" and come roaring back in a few months, almost without fail. Because of that population variance. And the next time they are completely unresponsive to the vaccine. The population variance tends to overlap extensively with the variance of the normal body cells, which is why curing cancer *in general* seems to be nearly or actually impossible.\n\nCalling them \"vaccines\" I think is a bit of marketing. They are not vaccines, since they are not meant to prevent cancer, unlike the HPV vaccine for example. It's marketing to get people to trust it a bit more, I think. I would call them immunotherapy, just because that's really what it is. But, in my cynical opinion, the reason why immunotherapies are getting hyped so much is because there's TONS of money in it. It's not creative, risky work so much anymore. Corporations or investigators just follow a known and predictable process to generate these antibodies. Build an custom antibody, patent it, and sell it. And it's all patentable, every new target, every new cancer is a unique invention. And treatments can cost hundreds of thousands of dollars for these cancer vaccines. That, in practice, yes, are almost certainly doomed to ultimately fail (won't cure the cancer). However, they are also very likely to reliably prolong survival, especially in cancers where there was nothing else you could do a few years ago to even budget survival a little bit. So, want to make a few billion dollars? Find a cancer for which no current practical therapies exist -- a nasty, lethal cancer that kills people all the time with few options -- make an immunotherapy to it. Show any kind of efficacy, and bam: Instant money. Is that the way we should be running medical research and making healthcare decisions? It doesn't matter, that's just how it's done. But, like I said, I'm probably cynical. \n\nSome people believe in this a lot and think it's the future. They know the problems but think if you just tweak it, it will work like gangbusters. That kind of tweaking is not what this article did, which would be a lot to ask. That's why it's buried in the middle of a pretty prestigious journal instead of the lead story for the most prestigious journals. Maybe the tweaks are possible someday and the therapy will work super consistent. Who knows, that's science. My personal and professional take is that the problems with immunotherapy are *probably* mostly intractable, that they've essentially already made almost all of the progress they are going to make, and that further advancements might help a few edge cases but will fall far short of a general cure for cancer."
]
}
|
[] |
[
"https://med.stanford.edu/news/all-news/2018/01/cancer-vaccine-eliminates-tumors-in-mice.html"
] |
[
[
"http://stm.sciencemag.org/content/10/426/eaan4488"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://fortune.com/2004/03/22/cancer-medicines-drugs-health/"
],
[],
[],
[],
[],
[],
[]
] |
|
34x4wg
|
Why do radar dishes need to spin and scan the area progressively? Can't they design a radar which scans the whole area?
|
We've all seen this kind of thing,
_URL_1_
As it spins it progressively scans the area and creates an image like this,
_URL_0_
Why do they need to spin? Can't we design a radar which doesn't need to progressively scan the area?
|
askscience
|
http://www.reddit.com/r/askscience/comments/34x4wg/why_do_radar_dishes_need_to_spin_and_scan_the/
|
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"It's due to the antenna design, as directional antenna can have a bigger range and better signal than omnidirectional.",
"I guess you could think of if by analogy with our eyes. We turn our heads to look at things because we have a narrow field of view. Radar is similar - it only gets information from in front of it, and so needs to be turned to look at everything around it. \n\nYou could, however, build an onmidirectional radar. It would put out a pulse in all directions and then listen for reflected radio signals from all directions. But there would be two big issues:\n\n* You'd not get, in an normal radar design, any information about what direction the detected object was in. You could tell how far away it was and how fast it was moving towards you, but not at what angle it was. You could add this information by having a group of antennae that effectively triangulate.\n\n* You'd need a lot of power, as unlike a normal radar, you'd be sending the radio power in all directions. If you didn't give more power, you'd have a much weaker return signal and thus a harder time to detect small or distant objects..\n\nEdit: bullet points ftw",
"They can make them so they don't spin, but it's cheaper to make them spin. A spinning radar sends out pulses in a narrow direction, and listens in that direction for reflections. The location on the screen is just the direction the antenna is pointing on the angular axis, and the distance is just the time for the signal to come back, and the brightness is the intensity of the signal.\n\nNow you can build a phased array, and use modern electronics to electronically spin the antenna, but that's a whole lot of money on electronics when a motor would work just fine. The other options is use a phased array to implement an omnidirectional antenna that works as an antenna pointing in all directions, but that requires MUCH more power to get the same distance, but it would scan the whole area in one go. It's also worth noting that you need fairly modern electronics to do that type of signal processing, and they didn't really have it more than 15 years ago.\n\nIt's also worth pointing out tracking radars, they don't spin, they are basically radar on a satellite dish, and you point the dish at your target. That lets them pick one object and get very up to date information on that one thing.\n\n"
]
}
|
[] |
[
"http://i.imgur.com/GmNaGi8.jpg",
"http://commons.wikimedia.org/wiki/File:HMAS_Adelaide_FFG01_main_radar_Dish.jpg"
] |
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[],
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|
1kotmw
|
What were some tools and technology utilized in the Golden Age of Arctic Exploration?
|
I am writing a short story inspired by the disappearance of my ancestor Roald Amundsen. Kind of a "Mountains of Madness" meets "Event Horizon" kind of short horror story / novella. What kind of equipment were must haves by the explorers of this time period and what inaccuracies would be most glaring in something I wrote?
Also if there was something you would love to see included in a work of fiction about the arctic explorers what would you like to see?
I was first inspired by reading "The Terror" by Dan Simmons and the fact that as a child I read a lot about my famous ancestor.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1kotmw/what_were_some_tools_and_technology_utilized_in/
|
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"Neat idea. Good luck!",
"I only know of Amundsen's expeditions in passing (at the \"Wikipedia\" level), but I've read books by and about pre-flight-era polar explorers. \n\nIn slightly earlier days, Norwegians like Amundsen had been noted for using more indigenous technologies and survival techniques than, say, the British (notably Scott). By the time he disappeared in 1928, technology had evolved so quickly and significantly (e.g. airplanes), it's likely that those national differences no longer existed, but I bring this up because it's possible that Amundsen's crew had different technology than the searchers. \n\nWhat I'd suggest is to find his most recent expedition memoir, which I gather is *Our Polar Flight: The Amundsen-Ellsworth Polar Flight* aka *My Polar Flight* (1925) which will hopefully give a good description of the preparation, equipment, clothing, safety considerations, etc his crew were using around that time. Also look for books by any of the other parties involved, or books describing the search efforts. I usually find that the explorers themselves go into more technical details and practicalities, rather than filling pages with biographical information, politics, legacy, etc. If your library doesn't have what you want, ask if they can bring them in on an inter-library loan.\n\nBTW, while trying to find his book online, I found a couple of film shorts [1](_URL_1_) and [2](_URL_0_) which you've probably already found, but in any case are great for visualization",
"Depending on the snow (incline, thickness) short and long skis (used by Amundsen on his South Pole expedition and Nansen's Farthest North expedition).\n\nSnowshoes (Fridtjof Nansen's Crossing of Greenland)\n\nSledges to haul provisions - dragged by either men or sled dogs (again, Amundsen South Pole and Fridtjof Nansen North Pole expeditions).\n\nRobert Falcon Scott used ponies to haul the sleds instead of dogs and that didn't work out so well. I'd presume the same could be said of using ponies in the North.\n\nPemmican -- something akin to beef jerkey -- would be eaten by humans or dogs. It's high in fat content so it provides many calories. Dried meats, because water is heavy and a burden to haul around. Biscuits. Tobacco, etc. This, again, makes sled dogs superior to ponies being that the food stores could be used by both humans and dogs. Ponies need hay, and that would be extra weight on the sledges that would be somewhat useless to humans. Other tinned goods would be added such as jams to provide some variety to the diet.\n\nFor the sleds, you'd need leather lashings of some sort to tie everything down, and then extra lashings in case the first ones broke. You would also need extra runners (skis on the bottom) for the sledges in case they break (which they will, it's the rough icy arctic).\n\nTents are a must. Sleeping bags are a must. Snow goggles to prevent snow blindness. Cocaine was sometimes used to help with the pain of snow blindness (staring at bright snow too long).\n\nBoots and pant linings were often made out of reindeer, sometimes out of specific parts such as the inside of the leg of the baby reindeer. \n\n*\"Reindeer-skin is, in comparison with its weight, the warmest of all similar materials known to me, and the skin of the calf, in its winter-coat especially, combines the qualities of warmth and ligtness in quite an unusual degree.\"* -Nansen (Greenland)\n\nFor a certain type of boot called 'finnesko', Nansen claimed the best were made out of reindeer leg skin from a buck.\n\nAdditionally, heavy woolen shirts and trousers were worn with layers of socks and gloves. To soak up moisture buildup in the boots and the gloves, Nansen would stuff 'sennegrass' near the feet and hands. [Sennegrass, according to the Meriam-Webster Dictionary: a widely distributed sedge (Carex vesicaria) with grasslike leaves that is used by arctic and antarctic explorers as insulating material ](_URL_0_)\n\nIn rain and blizzards, they would also wear a thin canvas overcoat to keep dry.\n\nA primus stove/cooker that runs on paraffin and/or alcohol is a must for heating up water and other food. It's been a while since I have read books on the matter, but I believe Nansen used seal blubber in place of oil/paraffin when the latter ran low. The primus would work, but would spew dirtier smoke since the blubber would be relatively unrefined.\n\nSpeaking of blubber. Harpoons. You're going to want some harpoons to hunt seals. Rifles as well, but harpoons will be good if you need to conserve ammo. You'll need some sort of knives to butcher the seals as well.\n\nSeals (and polar bears in the north) are another reason you'll want dogs. You can't feed seal/bear meat to ponies. And when you run out of food for the dogs, you can eat those as well (Nansen did just this in his Farthest North expedition)\n\nMotors aren't the best. At least not in the south pole expeditions. Too many pieces to break down and the gas/oil/other liquids would gum up at those low temperatures (Robert Falcon Scott brought a motor on his expedition -- it didn't work very long)\n\nFor shipboard entertainment, you'll want a library filled with books, and maybe a small piano/organ (Nansen expedition. Amundsen might have brought one South, too.) A small printing press to make a short \"newspaper\" is another way Polar expeditions have killed time in the long, dark winter. Cards. Cigars. Some alcohol. You have to keep spirits up. \n\nUsually on polar expeditions, they will bring scientific instruments for posterity. They'd bring *long* lengths of cable to make depth measurements around the shorelines of Antarctica. \n\nStraight out of Farthest North (1897):\n\n*\"The instruments of scientific observations of course formed an important part of our equipment, and special care was bestowed upon them. in addition to the collection of instruments i had used on my Greenland expedition, a great many new ones were provided, and no pains were spared to get them as good and complete as possible. for meteorological observations, in addition to the ordinary thermometers, barometers, aneroids, psychrometers, hygrometers, anemometers, etc., etc., self-registering instruments were also taken. of special importance were a self-registering aneroid barometer (barograph) and a pair of self-registering thermometers (thermographs). for astronomical observations we had a large theodolite and two smallers ones, intended for use on our sledge expeditions, together with several sextants of different sizes. We had, moreover, four ship's chronometers, and several pocket-chronometers. For magnetic observations for taking the declination, inclination, and intensity (both horizontal and total intensity) we had a complete set of instruments. Among others may be mentioned a spectroscope especially adapted for the northern lights, an electroscope for determining the amount of electricity in the air, photographic apparatuses, of which we had seven, large and small, and a photographometer for making charts. for hydrographic observations we took a full equipment of water-samplers, deep-water thermometers, etc. to ascertain the saltiness of the water, we had, in addition to the ordinary areometers, an electric apparatus specially constructed by Mr. Thornoe. Altogether, our scientific equipment was especially excellent, thanks in great measure to the obliging assistance rendered me by many men of science.\"* \n\nsources: \"Farthest North (1897)\" by Fridtjof Nansen. \"South Pole (1912)\" by Roald Amundsen. \"First Crossing of Greenland (1880)\" by Fridtjof Nansen."
]
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[] |
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[],
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"http://www.dieselpunks.org/video/roald-amundsen-lincoln-ellsworth-polar-flight-1925",
"http://www.youtube.com/watch?v=aLeLohOIsD4"
],
[
"http://www.merriam-webster.com/dictionary/sennegrass"
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|
bwwd2v
|
what are apertures, f-stops, how does depth of field work, and how does lens measurement factor into the equation?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bwwd2v/eli5_what_are_apertures_fstops_how_does_depth_of/
|
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"An ideal lens focuses light from a single plane (called the focal plane) onto its sensor. However, that's not super useful, as we often want to take pictures of things that are thick. As it turns out, there is a region around the focal plane where the image is still well focused. This is called the \"field\" of the photo, and the \"depth of field\" (DOF) measures the thickness of this region from the point nearest the camera that is well focused to the farthest point that is well focused.\n\nAs it turns out, actual lenses are not ideal lenses. This matters when it comes to DOF. At small apertures, much less light enters the lens, and it all enters through the middle part of the lens. The result is a larger DOF. In fact, you can make pictures with no lens at all using a pinhole camera. The aperture is so small that the DOF is essentially infinite. Since the amount of light that comes through is similarly small, you need a very bright scene.\n\nSince aperture effects both amount of light and DOF, it's not exactly a DOF control. As less light comes through, more integration time (or exposure time if you're still thinking of a film camera) is required to get an image.\n\nf-number (or f-stop) is a ratio of aperture to focal length. This is a camera-specific idea, but the exposure time for similar f-stops is similar. This was a more interesting parameter when light meters were separate from cameras. Almost all modern cameras use through-the-lens metering and automatic (or at least semi-automatic programs) to select appropriate f-stops and exposure times."
]
}
|
[] |
[] |
[
[]
] |
||
34oh2g
|
why do i have to wait 30 seconds after i unplug my modem to plug it back in? once it's off, isn't it just...off?
|
When resetting a modem, why does the 30 second time limit matter?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/34oh2g/eli5_why_do_i_have_to_wait_30_seconds_after_i/
|
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],
"score": [
7,
26,
7,
2,
4
],
"text": [
"there are various components that still hold a slight electric charge for a few seconds after you disconnect the power cord. leaving it unplugged for 30 seconds or so allows these components to completely drain making the power cycle completely effective. ",
"Electronics contain capacitors and will maintain a capacitive charge for some length of time. The 30 second window is intended to be enough to let that capacitive charge drain. Not starting discharged can lead to some sequencing problems as the modem powers back up. In a perfect world they'd be designed such that it wouldn't matter, and it usually probably really doesn't.\n\nYou can see it one some electronics when you unplug them and the LED slowly fades out rather than going blank entirely.",
"It has to do with provisioning at the ISP side. Generally they ask for power off for a few minutes, this causes their equipment to \"release\" your modem's information, so when you turn it back on, it acquires new information, be it IP address, updated firmware, whatever.\n\nIf they do tell you \"30 seconds\" - it's either their equipment can be told to manually drop the stored information, or, they want to be SURE you actually powered it off, and will ask you \"what lights are blinking?\" - this proves you didn't just blow the tech off and not power cycle it. ",
"I work for an ISP. We tell you 30 seconds, because it is long enough to make sure that everything fully powers off. if you pull the plug and put it back, sometimes it won't reset.\n\nAs for the reset button, if you don't hold that down for 30 seconds it won't actually wipe the config file on our modems.",
"Most of these answers are right to some extent but aren't explaining the whole / true reasoning.\n\nYour modem automatically sends information to your ISP (pings) ever so frequently in order to let them know that your modem is still online. These pings contain your modem's MAC address which is a unique serial to your modem. When you unplug your modem and instantly plug it back in, the pings resume without a large delta (time gap from the last ping). Once a ping hasn't been received after a certain amount of time (between 5 - 15 seconds) the ISP's devices can determine that your modem is offline and then do things like releasing your stored MAC address to IP allocation. By waiting a full 30 seconds, both you and the ISP support technician can ensure that the ISP's devices recognize that your modem is offline / has restarted.\n\nSrc: Network Engineer / Computer Scientist"
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
|
1t4uaz
|
What advice can askhistorians give me on becoming a professional historian.
|
I have loved history as long as I can remember. I would much rather watch a PBS documentary on the civil war than a sitcom. I have my Bachelors degree in American history, and in January I am starting a master of Arts teaching degree at USC with an emphasis in social studies. I'm hoping if I do well enough I can apply for a phd program. Is there anything current historians or those desiring to become one can offer as advice?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1t4uaz/what_advice_can_askhistorians_give_me_on_becoming/
|
{
"a_id": [
"ce4fowl"
],
"score": [
3
],
"text": [
"Not to dissuade any new advice, but we've collected past posts in this topic under the FAQ section [History Careers and Education](_URL_0_)."
]
}
|
[] |
[] |
[
[
"http://www.reddit.com/r/AskHistorians/wiki/theory#wiki_history_careers_and_education"
]
] |
|
9rproh
|
Why so much variation in the spelling of Irish surnames?
|
There seems to be a wide variety of spellings of Irish surnames in the United States, such as Monahan/Moynihan/Monaghan, and O’Neill-O’Neal. This seems surprising to me given that Ireland was hardly a pre-literate society when the Irish immigrants were coming to America.
Why is this, and does this variety also exist in Ireland? Are they truly different surnames that happen to have similar spellings? Are they the product of Ellis Island mishearings? Do they reflect different regional accents or speech patterns?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/9rproh/why_so_much_variation_in_the_spelling_of_irish/
|
{
"a_id": [
"e8j9b34"
],
"score": [
3
],
"text": [
"It's a byproduct of British colonialism. During their process of colonisation, the English settlers often took Irish names - of people and places - and Anglicised them. For example, the capital of the Republic is Dublin, based on the viking settlement that used to be there called Dubhlinn (Blackpool if translated literally). More than that, though, while Irish was never prohibited in general (contrary to many popular myths), English was the language which dominated the Irish education system and civil service, and English was taught *exclusively* in the education system until 1871. There was major social pressure from the Catholic Church as well to discontinue the usage of Irish and they advocated against people speaking it until around the 1890's. \n\nThat attitude continued among a huge section of Ireland in spite of the Cultural Revival at the turn of the 20th century because employment opportunities were to be found in the Anglosphere - the United Kingdom and the United States, so Irish people were encouraged to learn English for when they would \"inevitably\" emigrate.\n\nNow to the thrust of your question; Irish people's names are spelled with such variety because they weren't originally in English. They had to be Anglicised at some point and the method in which that was done wasn't done so consistently. O'Neill vs O'Neal vs O'Neil for example, would translate roughly back to Ó'Néill (grandson/descendant of Néill). Another example could be Piers v Pierce v Pearse v Pearson, which would go back to Mac Phearais (or Nic Phearais if they were a woman).\n\nThat's not to say Irish names in the original format are extremely consistent either. Ó'Néill could be Ua Néill, or Uí Néill, or Ní Néill but that's defined by rules - depending on stuff such as a person's gender."
]
}
|
[] |
[] |
[
[]
] |
|
qkbsv
|
Would it be possible to create a stable, artificial ring around our planet (any celestial body, really)?
|
That space elevator question was very interesting and got me thinking...
Assume we have all materials and technology for this, assume it is technically feasible to put everything needed into orbit. I don't see why this isn't possible, but I may be wrong. My reasoning is this: we can put satellites in geostationary orbit. So, we put thousands in the same orbit and connect them together, thus a ring is created.
Better yet, instead of some magic cables connecting the satellites, we fill the gaps with other materials to create a uniform density ring in GEO. Would such a structure be stable? What if it was large enough to live in?
Also, if it is possible to create such a structure, could it be placed in any given orbit, so long as it is spinning at the appropriate speed?
Something like [Ringworld,](_URL_0_) but on a *much* smaller scale.
|
askscience
|
http://www.reddit.com/r/askscience/comments/qkbsv/would_it_be_possible_to_create_a_stable/
|
{
"a_id": [
"c3ym7k8"
],
"score": [
2
],
"text": [
"The issue is the amount of material you're talking about. Realistically you'd want to push asteroids around to form the belt. Then your main issue is what is this going to do to the gravity of the earth/moon system.\n\nLets throw some numbers around for fun. Average asteroid density is about 2g/cm^3 and a megastructure at geosync orbit that's 10m x 10m gets us 6.1* 10^13 kg. The gravitational pull on the surface would be ... OK my math broke down since it's a toroid and computing the gravity is problamatic. Either way we're talking a huge amount of mass but honestly with careful calculation and some good heavy list rockets and some extra-planetary tugs I don't see why it can't be done. It could even serve a purpose in that it's a great ancher for large space manfacturing and it's minimal gravity pull would clean out a lot of space junk in geosync.\n\nIf we could build one in LEO then it would be a lot smaller but it would need some kind of structural integrety to keep itself up as LEO still experiences some drag from the upper atmosphere. We don't want to be parking large asteroids there as without maintenence they'll fall on us fairly fast. Geosync has much less of that problem. Edit to add: 8.5 * 10^12 kg of mass there. That's only a cubic mile of material - not something we can launch but we could get a series of asteroids into place fairly easily. It's just then the question of how to keep them in orbit.\n\nedit: forgot to add earth to the radius of geosync"
]
}
|
[] |
[
"http://en.wikipedia.org/wiki/Ringworld"
] |
[
[]
] |
|
6pkxoc
|
why do brass instruments only emit a sound when pursing your lips? why can't you just blow into them and make sound?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6pkxoc/eli5_why_do_brass_instruments_only_emit_a_sound/
|
{
"a_id": [
"dkq4gxo",
"dkq4s8t"
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"score": [
10,
3
],
"text": [
"There needs to be some kind of vibration. Your lips vibrate in the mouthpeice and the instrument basically amplifies that vibration. If you just blow all you do is move air though a bunch of tubes. A saxaphone is brass but is considered a woodwind instrument because they have a wooden reed that emits the vibration.",
"Sound is really just the air vibrating. In order for anything to make sound, it must make the air vibrate. A piano makes sound because a hammer hits a string, and the string vibrates, and then that causes the air to vibrate too. This basically the way all 'string' instruments (like the guitar, violin or cello) work.\n\nThe other large class of musical instruments are the wind instruments. Some of these wind instruments work when you just blow into them (like a recorder), and some don't, but all of them must make vibrations. The instruments that work when you just blow into them work in two steps: first your breath passes though some device so that is makes a \"whushing\" sound. This sound contains a very large range of musical notes, all sitting on top of each other. Then this \"whushing\" sound enters a tube. The tube will only allow a particular musical note to come out: the longer the tube, the lower the note. Here, the air inside the tube is like the string in string instruments, it vibrates at a particular frequency, and this is the sound you hear.\n\nLots of instruments that you blow into, however, do not work this way. Many of them require you to make a particular note first, like a clarinet or a trumpet. Here, you make a note with your lips (or with the reed in a clarinet) and then this note moves into the tubes of the instrument, which again, will only vibrate at a given note, depending on the length of the pipe.\n\nSo why can't you make a \"whushing\" noise, and have a trumpet or clarinet work? You probably could, (especially in a clarinet) it just wouldn't be very loud. Because of the different materials/construction different wind instruments are better at filtering out all the unwanted notes in the \"whushing\" noise, and leaving and making louder, the note you want.\n\nThis all comes down to an idea in physics called resonance, that you should probably look up!"
]
}
|
[] |
[] |
[
[],
[]
] |
||
2khmos
|
What type of wood was the medieval trebuchet made of?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2khmos/what_type_of_wood_was_the_medieval_trebuchet_made/
|
{
"a_id": [
"clljv3q"
],
"score": [
6
],
"text": [
"In all likelihood most siege engines would have been a melange of cut and scavenged woods, some chronicles testify to ships hulls and masts, and houses, torn apart. However, oak and beech are the most common references in chronicles from Charlemagne (8th c CE) to Froissart (14th c CE), but that would be in areas where it was plentiful from forests in France, England, Germany. Fir was a good replacement: a strong tree with height and stoutness. Ash as well would have been a good substitute for some parts under some stress where flex was acceptable, and it was common for wheels, although did not grow as big. Hornbeam for axels where available, pretty much the hardest wood in Europe although did not grow in size like other trees. \n\nOnce you get to the Levant there are stories where crusaders needed to travel miles around to find suitable woods, although the woods are not named. The plentiful pines would have been liable to snapping, although Arabic siege engines were made of cedar according to one chronicle of the 8th c CE."
]
}
|
[] |
[] |
[
[]
] |
||
uufd1
|
Are quarks affected by magnetic fields?
|
askscience
|
http://www.reddit.com/r/askscience/comments/uufd1/are_quarks_affected_by_magnetic_fields/
|
{
"a_id": [
"c4ymwf2",
"c4yn7i7"
],
"score": [
6,
3
],
"text": [
"Yes, though quarks are never found alone.\n\nAnything with electric charge can be affected by a magnetic field.\n\nA proton is made of two up quarks and a down quark; it has a charge of +1.\n\nThe up, charm, and top quark have a charge of +2/3. The down, strange, and bottom quark have a charge of -1/3.",
"Yes. Consider neutrons for example, that interact magnetically despite having no net charge."
]
}
|
[] |
[] |
[
[],
[]
] |
||
5fut2f
|
how does my printer know how much ink is in the cartridge?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5fut2f/eli5how_does_my_printer_know_how_much_ink_is_in/
|
{
"a_id": [
"dan8axt"
],
"score": [
2
],
"text": [
"the inkjet cartridge has a electronic chip inside that counts how many times its asked to jet ink of each color. reach the upper end of that count and you have a good idea when it's going to run out. \n\n"
]
}
|
[] |
[] |
[
[]
] |
||
jvhga
|
I have a question for you /r/askscience. Is this some kind of hoax, or can this really work? I'm looking forward to your downvote if it is a duplicate. Reposted from /r/physics
|
Hi! I found some intresting, inexplicable (maybe just for me) experiment: _URL_0_ . Can someone explain me how it works? That is particulary intresting because it dosent work in both directions.
I'm sorry if I did something wrong, I'm new here.
|
askscience
|
http://www.reddit.com/r/askscience/comments/jvhga/i_have_a_question_for_you_raskscience_is_this/
|
{
"a_id": [
"c2ffrln",
"c2fft3m",
"c2ffxsm",
"c2fiax9",
"c2ffrln",
"c2fft3m",
"c2ffxsm",
"c2fiax9"
],
"score": [
2,
4,
2,
2,
2,
4,
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2
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"text": [
"Can you summarize the video for those of us at work?",
"A simple search in askscience for your post turned up no results (it took a lil bit of digging to find this, and I only kept looking because I knew it was there) so you haven't done anything wrong but it has already been asked:\n\n_URL_0_\n\nEDIT: grammar",
"It appears to be fairly simple magnetic propulsion. Keep in mind that the magnets are slowly losing energy each time he is doing this.\n\nI'd also note he hasn't demonstrated the ability to take a curve nor any significant inclination over time (which would be a requirement for his idea to loop back and 'drop' it back on the starting point.\n\nHe kind of loses it about 1/2 way through where he halves the track and then does it the opposite direction - because he forgot to remove the 'raise' he put under the leg (so now it is actually going a bit downhill) - but whatever.",
"A static magnetic field (and gravity) is conservative, so you're not gaining or losing energy, just converting it between potential and kinetic. Placing the magnets in a particular arrangement takes some amount of energy. Some of that energy can be converted to kinetic energy, but you're not going to get kinetic energy without losing potential. \n\nWhen he says:\n\n > It possibly could run continually by itself\n\nHe's wrong. It can't. He puts potential energy into it by placing it at one end of the track and that energy is converted into kinetic energy.",
"Can you summarize the video for those of us at work?",
"A simple search in askscience for your post turned up no results (it took a lil bit of digging to find this, and I only kept looking because I knew it was there) so you haven't done anything wrong but it has already been asked:\n\n_URL_0_\n\nEDIT: grammar",
"It appears to be fairly simple magnetic propulsion. Keep in mind that the magnets are slowly losing energy each time he is doing this.\n\nI'd also note he hasn't demonstrated the ability to take a curve nor any significant inclination over time (which would be a requirement for his idea to loop back and 'drop' it back on the starting point.\n\nHe kind of loses it about 1/2 way through where he halves the track and then does it the opposite direction - because he forgot to remove the 'raise' he put under the leg (so now it is actually going a bit downhill) - but whatever.",
"A static magnetic field (and gravity) is conservative, so you're not gaining or losing energy, just converting it between potential and kinetic. Placing the magnets in a particular arrangement takes some amount of energy. Some of that energy can be converted to kinetic energy, but you're not going to get kinetic energy without losing potential. \n\nWhen he says:\n\n > It possibly could run continually by itself\n\nHe's wrong. It can't. He puts potential energy into it by placing it at one end of the track and that energy is converted into kinetic energy."
]
}
|
[] |
[
"http://www.youtube.com/watch?v=5TMKMoGLVcw"
] |
[
[],
[
"http://www.reddit.com/r/askscience/comments/jsdfz/what_is_going_on_here_strange_magnetic_propulsion/"
],
[],
[],
[],
[
"http://www.reddit.com/r/askscience/comments/jsdfz/what_is_going_on_here_strange_magnetic_propulsion/"
],
[],
[]
] |
|
2z5s23
|
Was former L.A. Mayor John Porter a member of the Ku Klux Klan?
|
I am in the process of writing a research paper about how the KKK influenced California during 1920-1930s. In my research I came across a claim that Porter was current member/former member of the Klan, but nothing really concrete. I've searched my school's databases rigorously, but haven't found much more about him. Does anyone know if there is merit to these claims or was it mainly hearsay? Also, any sources or possible sources would be appreciated. Thank you guys for your time.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2z5s23/was_former_la_mayor_john_porter_a_member_of_the/
|
{
"a_id": [
"cpfy6lj"
],
"score": [
3
],
"text": [
"Not a historian, but you might look at the [San Diego History Center](_URL_3_) for answers on this. They appear to have some primary sources in their collection, but specifically on this they site Kevin Starr's Material Dreams: Southern California through the 1920's (New York: Oxford University Press, 1990). \n\nI also found a [1931 news article](_URL_2_) that mentions it, charging him with \"bias to Jews, Blacks and Negroes.\"\n\nMichael Newton's [White Robes and Burning Crosses: A History of the Ku Klux Klan from 1866](_URL_1_) mentions him.\n\nYou should also seek out the book [Chronological Record of Los Angeles City Officials: 1850—1938](_URL_0_) in a library. You might also look in LA newspaper archives - he was accused of being endorsed by the Klan and admitted his prior membership, so there should be something in the archives from 1928. "
]
}
|
[] |
[] |
[
[
"http://www.worldcat.org/title/chronological-record-of-los-angeles-city-officials-1850-1938-supplement-july-1-1937-june-30-1965/oclc/10140559",
"https://books.google.com/books?id=NT0xBgAAQBAJ&pg=PA60&lpg=PA60&dq=los+angeles+mayor+john+porter+KKK&source=bl&ots=U3v7LzZ2Jr&sig=pezmw7xBYxnUY2wD9hbfA27sn6E&hl=en&sa=X&ei=R_cFVYa4HYuuggTI0YHoBw&ved=0CDoQ6AEwBA#v=onepage&q=los%20angeles%20mayor%20john%20porter%20KKK&f=false",
"http://www.jta.org/1931/07/13/archive/los-angeles-mayor-charged-with-bias-to-jews-negroes",
"http://www.sandiegohistory.org/journal/2000-2/klan.htm"
]
] |
|
wgfqv
|
How come we can see distant galaxies but just recently discovered Pluto's fifth moon?
|
The Hubble telescope and others have shown us pretty clear pictures of galaxies that are thousands of light-years away. That being said, how come just within the last day or so we discovered that Pluto has a fifth moon, P5? I understand that the moon is incredibly small, but how come we can see objects so far away but cannot view things relatively closer?
|
askscience
|
http://www.reddit.com/r/askscience/comments/wgfqv/how_come_we_can_see_distant_galaxies_but_just/
|
{
"a_id": [
"c5d3irb",
"c5d3kyz",
"c5d48nc"
],
"score": [
27,
3,
3
],
"text": [
"Galaxies and stars are very bright, so you can see them from farther away. Pluto and its moon do not emit light and all we see from them is reflected sunlight off their surface. \n\nIt's kindof like how you can see a streetlight from miles away at night, while you can't see the rock 10 feet away. ",
"Galaxies emit light, and lots of it. Spectacularly large amounts - a single galaxy can contain hundreds of billions of stars. Pluto's moon, on the other hand, is very small and emits light only by reflection from the Sun. What this means is that the amount of light received by a telescope on or near Earth from Pluto's moon is actually less than that received from many distant galaxies, making it harder to spot. There's the added complication that it moves around, since it's orbiting Pluto, whereas distant galaxies are effectively stationary in the sky, meaning a long exposure image won't necessarily detect it.",
"While galaxies are much, much further away from us than pluto is, they are also much, much larger than pluto.\n\nCheck [this pic](_URL_0_) of the relative sizes in the night sky of the andromeda galaxy and the moon.\n\nAs you can see, on a clear night far from city lights you could probably perceive the galaxy with your naked eye simply because it's so huge in the night sky.\n\nPluto, by comparison, would be impossible to spot with the naked eye because, despite its proximity to us, it is extremely small.\n\nIt's like being on top of a mountain and wondering why you can see the small patch of forest 60 miles away, but cannot see the mite of dust 5 feet away from you."
]
}
|
[] |
[] |
[
[],
[],
[
"http://farm7.static.flickr.com/6216/6230985836_6007b65532.jpg"
]
] |
|
1q2vdg
|
how much money (usd) would need to be "destroyed" in order to see a significant rise in the value of the dollar?
|
If the value of money goes down as more money is put in circulation, taking some out would make the value go up, right? So how much cash would need to be burned to actually see a real change in the power of the U.S. dollar?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1q2vdg/eli5how_much_money_usd_would_need_to_be_destroyed/
|
{
"a_id": [
"cd8n0la"
],
"score": [
3
],
"text": [
"_URL_0_\n\nThe monetary base went from ~800 billion USD in 2008 to 3.6 trillion 2013 and you had ~10% cumulative inflation over 5 years.\n\nSo if you want to roll back that inflation you'd need to eliminate at least 80% of the monetary base (note that much of the monetary base is electronic), and that might get you back to where the US dollar was in 2008.\n\nIt's a non trivial question honestly, causing deflation - even a trivial amount would cause huge damage to the US economy, which would have effects of the US dollar. "
]
}
|
[] |
[] |
[
[
"http://research.stlouisfed.org/fred2/series/BASE/"
]
] |
|
bgn603
|
what is the purpose of that transparent blue strip on the top of the windshield glass of almost every car?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bgn603/eli5_what_is_the_purpose_of_that_transparent_blue/
|
{
"a_id": [
"elm7288"
],
"score": [
7
],
"text": [
"As the sun starts to set it can be shining directly into the drivers eyes. The shade strip lets you block some of that without having to tint the whole window which would make it harder to see out at night."
]
}
|
[] |
[] |
[
[]
] |
||
5uldrh
|
why primary education is disproportionately a female institution?
|
Surely both male and female children need equality in their role models?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5uldrh/eli5_why_primary_education_is_disproportionately/
|
{
"a_id": [
"dduw6sp",
"dduxfbe",
"ddv3i2t"
],
"score": [
4,
2,
2
],
"text": [
"That's a pretty tough question to answer, and I think it also depends on the country you live in. \n\nA lot of people think that the reason there are a majority of female teachers is because society puts pressure on girls to go into fields that have a more nurturing nature like teaching, child care, and nursing/medical fields. \n\nOr it could be that, in general, women are more likely to go into fields like that because of their biology, as women are more genetically programmed for these types of things. Or maybe they just enjoy it more. \n\nIt's really more of an open-ended discussion than a cut-and-dry answer. ",
"It's work that the average woman would find more suitable as there is less physical labor and more interpersonal skill necessary. Plus women are generally seen as being more trustworthy to be around kids, especially with all the pedophile hysteria in recent years.",
"This might be somewhat off topic but I work somewhat with nurses by delivering them their patient's medication. It is surprising how many men are nurses. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
11j430
|
When you lose your memory, or if you have a hard time remembering things, is that because your brain can't "store" the memories properly or because it can't "retrieve" them properly?
|
I don't have much more to add to it than that... It was just a random question that popped into my mind when I was trying to remember something.
And I remembered reading somewhere that you can't "make characters" for your dreams, they're all people that you've seen some where at some point in time. So I started to wondering why is it I can't remember something important but I can remember a guy I passed on the sidewalk.
|
askscience
|
http://www.reddit.com/r/askscience/comments/11j430/when_you_lose_your_memory_or_if_you_have_a_hard/
|
{
"a_id": [
"c6mxunk"
],
"score": [
2
],
"text": [
"The answer really is \"it depends.\" Disruption in both storage (called encoding) and retrieval can both disrupt your ability to recall memories. There is quite a bit of debate about exactly what goes on when you forget something, with some people arguing that the memory trace (typically referred to as an association) simply decays due to time, while others believe that you build a new association and that this disrupts the original.\n\nThere's a lot of interesting research in the area of directed forgetting that tackles this exact problem. They have shown that intentional forgetting is much more effective if you use a replacement for the association (like if you are trying to forget the word \"bed\" when you originally associated it with \"queen,\" you would then try to memorize the word \"crown\" being associated with \"queen\" and you would be more likely to forget the word \"bed.\"\n\nMost of the evidence points towards both decay and new associations being responsible for forgetting.\n\nIf you spontaneously recall the memory later, then that would be a pretty strong indication that it was an issue with recall and not encoding."
]
}
|
[] |
[] |
[
[]
] |
|
3okz11
|
How often do neutrinos interact with us? What happens when they do?
|
And, lastly, is the Sun the only source from which the Earth gets neutrinos?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3okz11/how_often_do_neutrinos_interact_with_us_what/
|
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" > How often do neutrinos interact with us? \n\nA quick *literal* rule of thumb for neutrinos: 10^11 neutrinos pass through your thumbnail *every second*. It doesn't matter if it's day or night - they interact so rarely that using the earth as shielding won't make a difference. \n\nSo how many of them interact? Well, [your lifetime odds for a neutrino interaction in your body are about 25%](_URL_0_). This means the odds of a neutrino interacting are about 1 in 10^25. For perspective, there are about 10^21 grains of sand on earth, so if one neutrino passed through your body for every grain of sand on earth you could *literally bet your life on nothing happening* and you'd be pretty safe. \n\n > What happens when they do?\n\n[Depends on the energy and flavor of the neutrino.](_URL_2_) They could just bounce off an electron or neutron, imparting some energy in a collision, or they could be absorbed by a neutron and make a proton and electron. There's lots of fun possibilities.\n\n > And, lastly, is the Sun the only source from which the Earth gets neutrinos?\n\n\nTwo more rules I know for neutrinos: The sun emits about 2% of it's energy in neutrinos and about 98% as photons. A supernova, in contrast, releases 99% of it's energy as neutrinos, and only 1% as photons (imagine how much brighter a supernova would be if you could see the neutrinos :D). \n\nThere's a huge number of sources of neutinos, all with different energies and abundances. [Check this plot.](_URL_1_) Nuclear reactors make fucktons of them (among other terrestrial sources), and there's even more that form a sort of 'cosmic neutrino background' dating to the same time as the cosmic microwave background. Supernova and stars are another major source. \n\n\n------\n\nAnd my last favorite fun fact - [look at this picture.](_URL_3_) That is a picture of the sun, but it was *taken at night.* The camera is a neutrino detector under a mountain in Japan. *They took a picture of the sun, from underground, at night.* That's the power of neutrinos - they pass right through the world. This picture was taken with the SuperKamiokande detector in Japan, whose neutrino experiments earned the Nobel Prize last week for Takaaki Kajita, which he shared with Canadian astrophysicist Arthur McDonald. ",
"Neutrinos pass through us millions of times per second and almost never interact with us. \n\nWe are exposed to neutrinos from other stars, not just our own, and get an especially high dose when they go super nova.\n\nI heard that if you were at the orbit of mars when a super nova went off at the position of our sun, you could be killed by the neutrinos. Thats how powerful a supernova can be\n",
"I helped build a neutrino detector as a research assistant back in college. The detector is about 2.5 stories tall and wide, and as long as half a football field. It is located in northern Minnesota, and the beam that it is detecting is located near Chicago. The beam goes through the curvature of the earth practically unimpeded. Even then, most of the neutrinos pass right through the detector too without getting picked up. Only a very small number actually get detected. Check out the project though, if you are interested. It's called NOvA.",
"Randall Munroe (of xkcd fame) addressed a variant of this in his \"what if\" column. The question he answered was [How close would you have to be to a supernova to get a lethal dose of neutrino radiation?](_URL_1_) \n\nIn Munroe's investigation he poses a rhetorical question:\n\n > Which of the following would be brighter, in terms of the amount of energy delivered to your retina?\n\n * A supernova, seen from as far away as the Sun is from the Earth, or\n * The detonation of a hydrogen bomb pressed against your eyeball?\n\nIt makes for an amusing but informative read which augments the the [excellent answer written by VeryLittle](_URL_0_) above.\n"
]
}
|
[] |
[] |
[
[
"http://www.symmetrymagazine.org/breaking/2010/02/15/just-how-often-are-you-hit-by-a-neutrino",
"https://icecube.wisc.edu/icecube/masterclass/media/20",
"http://hyperphysics.phy-astr.gsu.edu/hbase/particles/imgpar/sud.gif",
"https://newhumanist.org.uk/images/CCWEB-Sun-at-Night1.jpg"
],
[],
[],
[
"https://www.reddit.com/user/VeryLittle",
"https://what-if.xkcd.com/73/"
]
] |
|
3694vk
|
Was Joseph Smith sincere?
|
A lot of people speak of Joseph Smith as a fraud or conman.
They state so unequivocally, as if the falsity of a believe is evidence of someone lying.
Yet while I don't believe in Mormonism (or any religion), I recognise the difference between something not being true and something being a fraud. I don't assume the founders of all religions are conmen, even though I don't think their religions are true.
There is evidence that Smith may have worked as a conman earlier in life (although even this might be disputed - he could have genuinely believed in his divining etc.), but is it thought that his religion was fraudulent, that he didn't believe in what he was saying, that he knew it was false?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3694vk/was_joseph_smith_sincere/
|
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"In short, we can show that Joseph and/or his compatriots were involved in intentional deception, explicit plagiarism, and attempts to bury evidence of misdeeds. I don't think we can ever completely rule out psychosis or an epic level of self-dillusion, but I think it highly unlikely considering what we know about his actions and behaviors. There's too much to write to go through it all, but I'll touch on some of the evidence below. \n\n1. As you mentioned, Joseph had a long history of cons and frauds. This started young as a failed seer or glass looker. He was involved in at least one expedition for buried treasure, along with his father. This produced no results. Every time they started to dig, Joseph would say evil spirits took the gold away. He was involved in a fraudulent banking scheme, which he fled from. He was involved in several secret and illegal marriages across multiple states, which he publicly and repeatedly lied about. There are others, but I mention these because they required an active attempt at deception. See [more information here](_URL_4_), and a copy of his youth arrest for [scrying here](_URL_1_). \n\n2. Joseph's origin claims are demonstrably fraudulent. For example, the Book of Mormon claims to have been completed in 600 BC and translated solely from that record in 1829; however, several verses were copied verbatim from the 1611 KJV + Apocrypha (his family bible), including [translation errors of the KJV translators](_URL_3_) (Joseph's family bible). There are many other examples of plagiarism, but this one is the most blatant. Again, something that required an intent to deceive. \n\n3. Joseph had a history of hiding evidence of his misdeeds. For example, we have one letter he wrote where he told a potential lover to [burn the letter to protect him](_URL_5_), one of his former wives [accused him of ordering abortions after impregnating a girl](_URL_2_), and ordering his secretary to [burn the minutes of his infamous council of 50](_URL_0_) (his attempt at the presidency) when arrested for treason. \n\n"
]
}
|
[] |
[] |
[
[
"https://web.archive.org/web/20150319092257/http://bycommonconsent.com/2013/09/11/the-council-of-fifty/",
"http://www.utlm.org/images/newsletters/no68highlightedbillwholep1.gif",
"http://en.wikipedia.org/w/index.php?title=Sarah_Marinda_Bates_Pratt&oldid=661028840#Allegation_of_abortions",
"http://en.wikipedia.org/w/index.php?title=The_Book_of_Mormon_and_the_King_James_Bible&oldid=652782240#Perpetuation_of_KJV_translation_variations",
"http://en.wikipedia.org/w/index.php?title=Joseph_Smith_and_the_criminal_justice_system&oldid=662764222",
"http://user.xmission.com/~research/family/strange.htm"
]
] |
|
q9sdb
|
Why do cochlear implants not produce normal hearing, and what would they need to do so?
|
Also, everyone talks about how cochlear implants have 24 or so channels and they seem to be the main limiting factor. What are these channels?
|
askscience
|
http://www.reddit.com/r/askscience/comments/q9sdb/why_do_cochlear_implants_not_produce_normal/
|
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"Your [cochlea](_URL_3_) is shaped like a snail shell. Throughout this shell, there are hairs that are triggered by different frequencies of sound. Hairs near the base fire in response to high frequency sounds. Hairs near the apex fire in response to low frequency sounds. \n\n[This](_URL_0_) is an artists rendering of what the array looks like in the cochlea. If this is a 22 channel array, there are 22 spots on the long inserted piece that will stimulate the cochlea at different points along the cochlea. Remember that different points along the way respond to different frequencies, so a 22 channel array would allow for 22 frequencies to be heard. \n\nThe sound produced by cochlear implants has become more realistic overtime because initially there was only one frequency/one channel and progressively more so that a patient can hear a wider range of frequencies and better distinguish sounds. \n\n[Wikipedia](_URL_1_) \n\nedit: [This is an article about cochlear implants, place theory, and channels](_URL_2_)",
"Cochlear implants excite nerve cells via an electrode array that is inserted into the cochlea. Each electrode in the array represents one of the channels you mention. This electrode array replaces the 1000's of hair cells in the cochlea that normally carry out this function. The electrodes cannot target nerve cells as specifically as the hair cells can, so there is a limit to how closely they can be spaced before no further benefit is gained.\n\nAlso, the ear has some pretty amazing mechanisms for processing sound. One example is a feedback mechanism in the cochlea that causes soft sounds to be perceived as louder than they are. This provides a huge dynamic range: we can hear everything from a mosquito or pin drop to a live concert. The cochlear implant doesn't provide as wide a dynamic range.\n\nInterestingly, 24 bands (channels) is around what we use for automatic speech and speaker recognition. The incoming signal is converted into a spectral (frequency) representation and grouped into about 20-24 critical bands prior to further processing.\n\nEDIT: Interesting - > Interestingly",
"medstudent22 is correct. Also, the main problem with CIs is that they can only act in a very linear way, and as we have learned with the invention of CIs, the auditory system is incredibly non-linear. One of the big discoveries was the afferent AND efferent neurons going to/from the hair cells. This means that there is information being sent FROM the brain to the hair cells. This is where and why things get complicated b/c this is not all that clear. So, the idea is that our brain (probably auditory cortex) is sending signals which can 'adjust' the hair cells in response to a stimulus. \n\nThere are actually 3 big companies that make CIs. One of them boasts more channels (i think it's 31 or 33). The idea is that this gives better pitch perception (which is the real problem area w/ CIs. Timing is just fine). However, no one has any real 'proof' yet on whether this is true for the patients. My lab is working on a way to test sound quality for this exact purpose. \n\nWe look at music perception in CI patients. and in a word, it's total shit. So, improving their pitch discrimination and thus improving their musical listening experience is something that we think is important and mostly ignored. ",
"There are already great responses here, but I want to add one thing about the interface between the electrodes and the auditory nerve.\n\nWhen a cochlear implant says it has a channel, 16-channels, 24-channels, 120-channels, what that means is that the frequency spectrum is filtered into that number of passbands. But the signal is not directly sent to the internal electrodes, it is processed first. The processing that occurs is the extraction of the amplitude envelope, which is the variation in the amplitude in that channel over time. If you are familiar with signal processing, it's basically the Hilbert envelope, lowpass filtered to 200-300Hz. In simple terms, this processing turns the original content of the channel into a smooth outline.\n\nThe extracted envelope in each channel is applied to a series of clicks, and the internal electrodes broadcast that signal as electric impulses. The impulses have the same smooth outline, or envelope, as the original signal in each channel. Those electric clicks cause auditory neurons to fire in much the same way as they would in a normal ear. The problem is that many of the neurons are dead, and many of the living ones are separated from the electrode by a wall of bone. When the electric impulses leave the electrodes they travel outward in 3 dimensions, and you can't control what neurons actually respond. You try to send a low-frequency channel to the region of the cochlea that would normally respond to low frequencies, but if there is a lower impedance to some other part of the auditory nerve, then you have a problem. The channels can blend together, or interact in strange ways. I think the main limitation in cochlear implants right now is the interface between the electrodes and the neuron, which is being addressed through research into releasing growth factor from the electrode array that can draw dendrites from the auditory nerve into closer proximity to the electrodes.\n\nOnce that interface is improved, more discrete channels can be used, a greater dynamic range of envelope can be transmitted, and more of the natural processing on the inner ear can be simulated. However, the issue raindiva1 brought up about efferent control of the cochlea will continue to be a problem. For that reason, a CI will not resemble normal hearing for many, many, many years. We will probably be able to grow you a new ear from stem cells sooner than we can interface your ear directly with a computer. But that's a hell of a long way off as well."
]
}
|
[] |
[] |
[
[
"http://entcentre.com/images/EndoAtlasPics/arrayincochlea.jpg",
"http://en.wikipedia.org/wiki/Cochlear_implant",
"http://www.utdallas.edu/~loizou/cimplants/tutorial/tutorial.htm",
"http://en.wikipedia.org/wiki/File:Cochlea.svg"
],
[],
[],
[]
] |
|
fte4e
|
If time stops completely at the event horizon, how can black holes grow?
|
It is my understanding, that the supermassive black holes in the center of galaxies became so massive because they were swallowing up surrounding matter for billions of years, not because they were so massive from the beginning. On the other hand, if time stops at the event horizon, it shouldn't be possible for matter to fall through and increase the mass of the whole object. This seems like a paradox to me.
I understand that time doesn't stop for the observer falling onto the BH. I'm asking about what happens from the point of view of an external static observer (us, Earthlings).
My best guess is that it can be explained as the infalling matter somehow "settling" on the surface of the event horizon - but even that would have to happen in infinite time, right?
So which is it? Is it that black holes don't grow, or that time doesn't really stop at the event horizon? Or maybe neither and there is some freakish explanation I havent thought of? ;)
|
askscience
|
http://www.reddit.com/r/askscience/comments/fte4e/if_time_stops_completely_at_the_event_horizon_how/
|
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"text": [
"What matters is the mass of the black hole from the black hole's perspective. And from its perspective, matter falls in just fine.",
"The answer is that it is really complicated. You are correct that for the schwarzschild metric around a black hole, the far away observer never sees anything actually reach the event horizon. However this assumes that the mass of the object falling in is much smaller than the mass of the black hole. If you take into account the spacetime distortion caused by the smaller object as it falls in, then the far away observer will actually observe the object reach the surface of the black hole at some finite time. Still, if the object is much smaller than the mass of the black hole then this time will be really long.",
"The phenomenon goes by the name *black hole complementarity.* Matter *both* falls into the singularity *and* stays fixed for eternity at the event horizon. Both things occur. This may sound like a paradox, but it really isn't, because no knowledge of what transpires within a black hole can ever filter out of it, so there's no actual contradiction, but merely an apparent one.\n\nIn a very real sense, there are two black holes. One is the black hole that exists to infalling matter; it's a point of zero volume and infinite density. The other is the black hole that exists to all observers who do *not* fall in; it's a spherical shell of energy that grows over time as more matter gets mushed up against it.\n\nSince from the outside a spherical shell gravitates exactly as it would if it were a point, we can tell no difference between the two. But the tiny void just outside the event horizon roils and churns at the quantum scale, and the fluctuations that are present there are determined by what's fallen into the black hole. This is the source of Hawking radiation: If the universe ever cools to the point where black holes can radiate their heat away — and it is not certain this will occur — then all the information that fell into the black hole will emerge again, bit for bit, albeit in an entirely homogenized form.\n\nBlack hole complementarity is a relatively new idea in physics, only having been first articulated back in the early 1990s. But in the years since, it's been universally accepted as the truth, as much as any notion that can't be experimentally tested or compared with observation can be."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
28fqva
|
in philosophy, what are epistemology and metaphysics?
|
I hear these terms thrown around often when reading about philosophy, but I've never been able to find a sensible answer to what they actually are. Can someone help me out?
Edit: Thanks, guys!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/28fqva/eli5_in_philosophy_what_are_epistemology_and/
|
{
"a_id": [
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"text": [
"True ELI5: \n\nEpistemology = \"How do I know shit? What does it mean to know shit?\"\n\nMetaphysics = \"What is this shit? What is shit? What is?\""
]
}
|
[] |
[] |
[
[]
] |
|
2zhbk5
|
how can we smell spring?
|
You can just feel it in the air... I am pretty sure it is something to do with pollen...
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2zhbk5/eli5_how_can_we_smell_spring/
|
{
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"text": [
"I'd like to think it's more a mass thawing of hundreds of petrified dog turds.",
"Pollen is just plant spunk. Walking outside in spring is like walking into a huge tree orgy. There really is something in the air, and on the ground, and covering your car (if you park under a tree)."
]
}
|
[] |
[] |
[
[],
[]
] |
|
6ek466
|
what's happening inside of a plasma ball?
|
I was have one and was wondering what the plasma and light was and why it's attracted to objects outside of the glass.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6ek466/eli5_whats_happening_inside_of_a_plasma_ball/
|
{
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"text": [
"Inside a plasma ball high voltage is used to strip electrons away from atoms of a noble gas (usually neon or argon). Plasma is a state of matter comprising these free electrons. Light (release of photons) happens whenever electrons change orbitals.\n\nThe stream of electrons are negatively charged and looking for a place to \"go\". Your body is a conductor so when you touch the globe you are presenting a path for these free electrons to go to."
]
}
|
[] |
[] |
[
[]
] |
|
28zam8
|
how could pixar produce toy story back in 1995?
|
Since it was rendered by computer, did they have a team of 500 PC's or something like that?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/28zam8/eli5how_could_pixar_produce_toy_story_back_in_1995/
|
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"text": [
"They had 117 computers running 24 hours a day, which could produce three minutes of the movie a week. It was slow.",
"Rendering 3d video is done through \"render farms\", which are essentially a bunch of computers in a warehouse turning the 3d models created by the artists into fully textured, high resolution video with lighting and particle effects - basically it turns it into a movie. Pixar has a 13500 square foot render farm which houses 3000 AMD processors, with the ability to add workstations to the farm pool after hours, increasing to 5000 processors. \n\nI don't know what their farm stats were in 1995, but they did it the same way. Create the model via wire frames and vertices, assign textures and lighting and effects, send it to the farm to be rendered into a final product. \n\nEdit: these numbers are out of date, from 2010. Apparently they had 12500 cores for Cars 2.",
"Look at Toy Story compared to the sequels though, they're a lot more primitive (still an amazing technical achievement and a great movie)\n\nAs processing power has increased, the depth and definition of Pixar's work has increased massively.",
"The whole reason for the concept of Toy Story is because of the limitations of the technology at the time.\n\nSomewhere in Pixar there was a conversation like \"Damn, our animation methods struggle to capture the complexity of human movement realistically, and when we render our characters they look like they're made of plastic. They look like toys.\" \"Fuck it, let's just have the characters be toys. Keep the humans off-screen whenever we can.\"\n\nLater, as the tech got better they could do insects for A Bug's Life, which move complexly but don't have skin and hair. Then they figured out hair/fur for Monsters Inc, then water for Finding Nemo. Notice how even in those films, adult humans are pretty much never seen. Then they could do people, but in a very cartoony way for the Incredibles, and then finally the more realistic human characters in Ratatouille and Up.\n\nBut toys are by far the easiest thing to animate and render, so they did that first.",
"If you can find it, checkout *[The Pixar Story](_URL_0_)* it is unfortunately not on Netflix anymore, but it is very interesting and explains to a certain degree what you are asking."
]
}
|
[] |
[] |
[
[],
[],
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"http://www.imdb.com/title/tt1059955/"
]
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|
5yvh3n
|
how do download and upload speeds actually work,(i.e how do they limit the speed of download through your cables)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5yvh3n/eli5_how_do_download_and_upload_speeds_actually/
|
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"They limit the speed of the download by limiting how many bits per second are allowed to transfer through the wire to you. Someone, somewhere tracks all the bits that go into your house, and counts those bits. Every second, that count \"refreshes,\" but if that count reaches the max rate, they stop sending traffic through until the next second.\n\nBasically, if your cable supports 10MBPS, they don't limit it by somehow making your cable support 5MBPS, they just transmit 5MB in half a second, then transmit 0MB for the next half a second.",
"I always assumed it had more to do with the physical meaning of \"bandwidth\" rather than the way we measure it in the computer world (digital transfer rate - i.e. Bits per second). I could be terribly wrong, so input is welcome. I'm also no pro, so I may jack up terminology.\n\n\"Bandwidth\" refers to a range of frequencies. Data (signals) is transferred over a cable using a certain frequency. Think of a dump truck. You fill it up with dirt and drive it across town but your max speed is limited by the street's speed limit. If you need to quickly move 5 loads of dirt, the people on both ends have to wait on you while you drive back and forth. That's not very fast. The solution? Fill up 5 trucks *at the same time* and drive them *at the same time* and you move 5 loads in the same time you could have moved one. It's similar with sending signals - you can only send the signals so fast, and then you have to wait before you send more. Solution? Connect 5 wires and send data over them all at the same time. Luckily, instead of adding more wires, you can use the same wire as long as you can use more than one frequency. If you can use 5 frequencies then you can send 5 different signals, each with their own frequency, *at the same time.* We can mostly thank Jospeh Fourier for this.\n\nAlmost 200 years ago some guy named Joseph Fourier realized that you can take multiple frequencies, mash them together to make one signal, then take them back apart, and end up with the exact same original frequencies. So now we can take 5 frequencies, upload/send data over each one, mash them together, shoot them through an Ethernet cable, and have a device on the other end that pulls them apart and receives the exact data you sent on each one. Alternatively, your computer can download/listen for the signal, split it apart into each frequency, and get that info from each frequency. (I think this is how cable worked - the cable company sends you all the channels down one wire, and when you turn the channel your TV just filters out the other frequencies and displays the one you wanted. Surely there's more to it, but I think that's the basics of cable tv, and explains why your neighbor could steal your cable!)\n\n**Wrapping up** (I promise)\n\nYour router/modem takes signals from all the computers connected to it, works that Fourier magic on those signals, and shoots the combined/composite signal to a magical cable in your wall that connects your house to the internet. That cable that brings internet to your house is connected (in my case anyway) to a big green box up the street. All of your neighbors' magic internet cables are also tied in there. I imagine that box kind of like a huge router (just like the one in your house). That big box takes signals from you and your neighbors, works it's Fourier magic on those signals, and sends it up the next wire. A group of those boxes all plug into an even bigger one, and so on until it connects back to the ISP. \n\nGo back to the dump truck example. If the dirt is the data, and each truck is another frequency, then the road is the wire. Even if you buy a million trucks, the road can only fit so many. Again, easy solution - upgrade the road by making it bigger. But that costs money! Instead, just make certain customers pay more money if they want their dirt faster. If you have 4 customers and one pays for quicker dirt delivery speed, then you can send 2 trucks together for his delivery and the other customers each get one truck for their delivery. \n\nApply that analogy:\n\nEach cable can only carry a certain range of frequencies (something in physics explains this), so those boxes do eventually max out data transfer. This can be fixed by using bigger, better boxes and cables all the way to the ISP, but it gets way too expensive. The solution?? --- > make a customer pay more money in order to have more frequencies available to them. So now you give the ISP more money, and they push a button that tells the box up the street to allow you to use a bigger *range of frequencies,* which we now know that a certain range of frequencies is also referred to as a *bandwidth.* Since downloading is the majority of internet traffic, they assign you many more frequencies for download than they do for upload. Once you run out of frequencies to use, you spend time waiting on your computer to finish using the current ones so that you can use them for something else.\n\nBoom. Done.\n\nI'm fairly positive that this is how it works, but it could all be monitored and regulated. Heck if I actually know haha"
]
}
|
[] |
[] |
[
[],
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] |
||
1djsdv
|
how come the zimbabwe dollar inflated so fast? how do people survive in a country with such hyperinflation?
|
Basically those two questions. I'd also like to know what's going on there right now - if your 100 trillion dollars is only worth 10 trillion tomorrow (lol) how can people even work and expect to survive?
Is the situation resolved? If so, how? If not, why not?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1djsdv/eli5_how_come_the_zimbabwe_dollar_inflated_so/
|
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"People stop using the currency and move to a barter system (or different currency). That is the resolution as well.",
"The president Mugabe is an EVIL dictator (arguably the worst on the planet) and he's printing money like crazy to fund corrupt politics in Zimbabwe.\n\nIt's not like people are having an easy time. Many are moving out of the country and but it's becoming more and more difficult as they become more poor. ",
"Economic growth can come from 2 areas, supply side or demand side. Supply side growth is long term, sustainable, and deflationary; it involves pushing out the maximum you can produce, by investing and improving infrastructure. Demand side means making people spend more, and a recession is caused by a lack of demand side growth. However, demand side growth is unsustainable. It leads to inflation.\n\n Demand side growth is short term, and can be easy, but it can only move so far. You can't buy more stuff then you have. One way of increasing demand side growth is called quantitive easing (it's sounds complicated, it's literally just printing money) and the Zimbabwe Govt did this loads; causing hyperinflation that crippled their economy. \n \nTL;DR Essentially is was a government looking for quick growth, without wanting to invest, so they printed money until everyone had so much it was meaningless - hence inflation.",
"Hyperinflation is typically caused when a nation goes through a major crisis (war, political turmoil, etc) and has a simultaneous need to spend large amounts of money. The tax base has collapsed and the uncertain economy makes international borrowing unavailable, so the government starts to print money. \n\nThe sudden, huge increase in the amount of money in circulation makes the currency less valuable. With the value of money shrinking, the government has to print ever more of it to meet its commitments. Very rapidly this turns into a spiral of hyperinflation. \n\nIn the case of Zimbabwe specifically, the country entered into a plan of forced land redistribution. At least initially, the idea was to confiscate farms from the descendants of former European colonials and give the land to the poorest indigenous people. There were many problems with this plan. Chief among them, the recipients of the land knew very little about farming so productivity collapsed. Foreign investors saw property being confiscated and left the market. To make matters worse, the land grants were frequently awarded to cronies of the Mugabe regime. The government printed huge volumes of money to try to make up for the lost tax base and foreign investment. \n\nHow do people survive? Well, you may have heard of other cases of hyperinflation from history where people try to adapt. In the southern US after the Civil War and in Weimar Germany after World War I, there were stories of people bringing cash to the markets in wheelbarrows to try to buy food. In some families, there are stories of people burning bundles of cash for heat in the winter because it was cheaper than buying fuel. \n\nIn Brazil there was a saying that you should always take a bus instead of a cab because on a bus you pay when you get on; in a taxi, you pay when you get out and there is no telling how much the currency may have devalued during the ride. \n\nAs others have said, many people turn to barter or other types of trade that are not dependent on currency. Sadly, in most affected countries, this also means a large increase in crime. \n\nThe interesting thing is that barter holds the key to how Brazil finally managed to beat decades of hyperinflation. Economists noticed that people bartering would settle on fairly standard relative values of goods: just as an example, imagine two potatoes for one tomato. These same ratios held for the prices in the markets. If a potato was $50, a tomato was $100. When potatoes hit $50,000 tomatoes were $100,000. \n\nThe economists called this \"real value\" and started referring to prices in units of real value. Storekeepers started putting units of real value in ads and on shelves and just posted an exchange rate between the currency and the real value (this was also much easier than re-pricing everything in the store every day). \n\nEventually, after a few years of this, the country just switched to a new currency. Each unit of the new currency was equal to one unit of real value. The currency was even called the *real* (in Portuguese, the plural is *reais*). The switch was remarkably smooth, since everyone was already thinking in units of real value. \n\nIt's kind of fascinating from a psychological standpoint as much as an economic one. You wouldn't expect that you could simply swap out a failed currency for a stable one, but in this case (with the right preparation) it actually worked. ",
"My aunt and uncle live in Zimbabwe (with my cousin before he was shot). We visited them in 2004. They are white, and they own a business, so they were lucky enough to have had money before the hyperinflation started. \n\nThey got around it by using foreign currency. Basically, South African Rand and American Dollars were used in place of Zimbabwean currency by most people. The tricky part is getting hold of Rand or US Dollars when nobody will trade them for your worthless Zimbabwean paper. There are several ways to do this. \n\nOne, used by my aunt and uncle, is to store any cash you have in foreign banks. They had bank accounts in South Africa and the UK. This works pretty well, but is not an option for most people in Zimbabwe since they haven't got enough money in the first place for a foreign bank account.\n\nThe more common method is for somebody in your family to leave the country and find work elsewhere, and then send their wages back to Zimbabwe in hard currency. Millions of Zimbabweans did this, amounting to about one out of every five or six citizens. Most went to South Africa, where living in a slum and working for less than what the locals will accept in wages (which is a pittance) is still seen as a more hopeful option than living in Zimbabwe. I think that these remittances supported most people in Zimbabwe for the last decade or so. \n\nThis phenomenon also achieves part of the governments political goals: there are two large tribes in Zimbabwe, and Mugabe is from the northern one. He indirectly oppresses the southern tribe by reserving government jobs for members of his own tribe, by directing foreign aid exclusively to his own people, and by generally disenfranchising the southerners. When millions of those people left the country to find work, he is happy to see his political enemies become somebody else's problem.\n\nFinally, people learn to be savvy and get their hands on usable currency whenever the opportunity arises. When we visited, we traded US $600 to my aunt and uncle in exchange for a suitcase full of ZIM $20,000 notes, which we used while we were in the country. Every market trader we traded with was willing to accept any foreign currency from a country without hyperinflation, in one case we paid with a mix of low-denomination (ones, fives, tens) Australian, British, American, and South African currency. This was preferred by the traders to the Zimbabwean currency, presumably since it could be used as a store of value.\n\nAs far as I know, Zimbabwe is no longer experiencing hyperinflation, thanks to the policies implemented by Morgan Tsvangirai and the MDC, the opposition party who are now in coalition with Mugabes ZPF in government (the MDC actually won the election, even in the face of massive fraud, but Mugabe would not step down so this was their best option).",
"I lived in Zimbabwe for a time. They use the US Dollar now, but back then we would spend our money as soon as we got it. You couldn't save it because it would be worth less the next day. As soon as you got paid, you bought all your groceries immediately. Most people survived by growing a lot of their own food. Nearly everyone has a garden.\n\nThe massive deflation on a 5 year old level: No one thought that Zimbabwe money was worth anything because the country's government was bad. As things got worse, people put even less value on the currency. ",
"I was in Zim a few years back and talked to a lot of people about what they went through. Normal people didn't have much savings anyway, they lived paycheck to paycheck. So when the shit started they would get paid everyday and buy groceries every day. You couldn't hold onto anything. One guy described it as feeling like falling off a cliff all the time. He actually worked in a Bank and did during the crisis.\n\nThe richer and upper middle classes already used foreign banks and currencies. I met one guy who was studying finance, but he was in Malaysia in school when it happened.\n\nI stayed with guys in Mbare which is the poor part of Harare. They also didn't really have anything to lose. They still have suitcases of trillion dollar bills.\n\nBut the biggest problem was that there wasn't anything to buy, because things couldn't be imported and the farmers collapsed, and they couldn't market crops correctly. Then the massive brain drain happened when 30% of the population left. Its still a big issue, most of the best most educated people simply left and can't come back. Many are in South Africa working and they send money home. \n\nZim has a better education system, they speak better English then the South Africans do, and to be frank they are more honest and better employees. So the South Africans hate them, rob them and even kill them.\n\nThe root cause of the inflation was that Mugabe had a lot of debt and decided to fuck the IMF by inflating his currency to pay off the debt. His economists were idiots.\n\nLastly - Zimbabwe is a great country with really friendly people. I met rastas and computer programmers, painters, school teachers, welders, sculptors and musicians. I definitely recommend visiting. they use USD and SA Rand for the coins."
]
}
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[
[],
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5llgje
|
in ww2 movies and rl videos some soldiers salute and some use nazi salute. why is that?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5llgje/eli5_in_ww2_movies_and_rl_videos_some_soldiers/
|
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"Nazi salute (with straight right hand) was mandatory for civilians but optional for military. Soldiers mostly used traditional salute. "
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||
2avydb
|
What happens when I take a USB drive out without ejecting?
|
Or a camera? I've been doing this most of my life and nothing has ever happened.
Edit: Wow!! Thanks for the replies guys
Edit 2: what I've learned from this thread: when in doubt; don't pull out!
|
askscience
|
http://www.reddit.com/r/askscience/comments/2avydb/what_happens_when_i_take_a_usb_drive_out_without/
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"When you eject a USB drive, the operating system flushes all buffered data to the drive and closes the software device. This guarantees that everything you wrote to the drive is actually physically written there. If you do not do this, you stand a chance of losing data or corrupting files. \n \nThe long version: Most operating systems maintain a memory buffer for each drive connected to the system. The buffer is used to cache data written to and from the drive, to speed up operations. Data written to the drive is first written to the memory buffer, then after a certain amount of time passes, or when enough data is written to fill the buffer, the contents of the buffer are actually written to the drive. Until this happens, the data is not actually on the drive, so if you lose power or yank the drive out the data will go missing. This could cause files to be lost, or if you were making changes to a file, the file could become corrupted because only part of it was updated. \n \nThe reason you have never experienced any problems is basically luck. Most devices and computers will flush their drive buffers periodically, so if you haven't written anything to the drive in a while it is probably safe to yank it out. But it is always better to eject the drive, to be certain everything has been flushed.",
"~~From an electrical point of view it implies little or nothing.~~ But from a software perspective there is some risk of information loss.\n\nBasically, writes to your device could be incomplete. The operating system may have a write cache to make the user interface more fluent, delaying the actual write to the external device. It may *appear* that a file has finished copying but it actually hasn't. If you've modified any directory entries (i.e. renaming or moving files) then things may get more complicated and the incomplete write may corrupt the whole directory causing the loss of several files.\n\nEjecting it makes sure the OS finishes anything it has to do and empties the write cache. If the device also has its own buffer, then the OS will send the instruction to commit the write to persistent memory.\n\n_URL_1_\n\n > I've been doing this most of my life and nothing has ever happened.\n\nThat's true, it's quite unlikely. Modern operating systems write everything to the external device as soon as possible to minimize the risk of data loss in these cases. But still there is a small chance that it happens.\n\n-----\n\nEdit: Sorry that I left so many followup questions unanswered! This was my last comment before going to sleep in my timezone. Fortunately I see that other redditors have already answered everything, thanks!\n\n-----\n\nEdit 2: A comment below reminded me something important about power cuts. I wrote all of the above thinking about flash drives. /u/PinguRambo suggests SSDs may be different, which also makes me think about spinning external disks (they are still used as their cost is a lot lower for the same capacity). If you unplug those without properly ejecting them then you also have some risk that heads are not properly parked.\n\nNot sure if modern disks are protected against that, but for safety it's usually strongly recommended to eject those properly. If ever an improperly parked head damages your disk you will lose just *everything*.\n\n_URL_0_ :\n\n > Head crash: a head may contact the rotating platter due to mechanical shock or other reason. At best this will cause irreversible damage and data loss where contact was made. In the worst case the debris scraped off the damaged area may contaminate all heads and platters, and destroy all data on all platters. If damage is initially only partial, continued rotation of the drive may extend the damage until it is total",
"In all cases, any file that is currently being copied to / written to the drive will not be properly written. That much should be obvious: it's impossible to finish writing something if you take away the drive in the middle.\n\nWhat state that drive remains in depends, however, on a number of factors. Chiefly, the \"filesystem\" on the drive. The filesystem is the way files on the drive are structured, filesystems include FAT32, NTFS, etc.\n\n* With some filesystems such as FAT32, removing the device during a write may corrupt the structure of the filesystem in such a way that the filesystem is broken or exhibits broken-like behaviour afterwards, requiring a repair operation (sometimes known as a \"chkdsk\" or \"fsck\"). This broken-like behaviour may include incorrect or corrupt metadata, such as incorrect file sizes and filenames, files which overlap or which have missing pieces, etc.\n\n* With some filesystems such as NTFS, ext3, ext4 and more, removing the device during a write may leave a partially written file, but the filesystem is not harmed structurally and does not require repair. The write that was happening at the time the drive was removed will be partially complete, and it may be unpredictable to determine how much of the write completed until you inspect the file. Depending on how the filesystem is implemented, some data in the not-yet-complete part of the file may be filled with random or unpredictable data. However, details such as the sizes and filenames of files will not have been damaged or corrupted and the drive will otherwise continue to work normally.\n\n* Some filesystems go even further than this and have the ability to automatically \"roll back\" a partially completed write to how it was just before the last segment was written - meaning that as soon as you connect to the drive again you'll find the file as it was before the last segment was written and the file size and and last update time will reliably reflect the last written segment that actually completed. (Note that these \"full journalled\" filesystems don't necessarily guarantee the atomicity on a whole-file basis but on segments written, with the segments determined by implementation.)\n\nDue to write caching in the operating system, the writes to a drive may be delayed by up to several seconds between the write appearing to complete and being actually written to the drive. This means that if you remove the drive during that time, the write that you thought had completed may not actually have been written to the drive yet.\n\nHowever, even if you disable write caching it does not stop the problem that some filesystems may be corrupted if the drive is removed during a write - and you may not always realise when something is writing to the drive.\n\nWindows tends to disable write caching by default for removable drives using the FAT32 system - the thought behind it is that it reduces the likelihood of corruption and lost data if the drive is removed after a write completes but before the write makes it from the cache to disk. However, you can still corrupt the drive if you remove it during a write - and for an NTFS drive, it will still be cached, so even though NTFS is resistant to corruption by incomplete writes, you'll still lose data if it hasn't made it from the cache to the disk.\n\nHow to be safe:\n\n* Always use the \"eject\" or \"safely remove\" feature in your operating system and wait for the message that tells you it's now safe to remove the drive. This will allow the OS to complete all unfinished business, including queued writes, leave the filesystem in a consistent state, and then disable further writes to the drive (usually by unmounting the drive, which also disables reads).\n\n* Shutting down or suspending the computer will also complete all unfinished business on all drives, so there is no need to \"eject\" or \"safely remove\" when you shut down or suspend (and by suspend, I don't mean just locking or going to screensaver). You can safely remove a drive while a computer is shut down or suspended at any time.\n\n* For NTFS, ext3, ext4 or other journalled filesystems, it is generally OK to remove the drive anyway as long as you wait at least 15 seconds after any important writes to the drive. When I say \"generally OK\" I mean it - it's not 100% safe. Also, doing this for FAT/FAT32 can still corrupt the drive if you don't realise something else is writing to the drive in the background.\n\n",
"(edit: this became longer than I expected, tl;dr at the bottom)\n\nThere's another factor in addition to the things other people have written, namely filesystems. This is arguably the biggest reason why you shouldn't just yank out USB drives.\n\nVery simply put, the file system is a data structure that is stored on a device that translates physical drive sectors into a usable directory structure. On a very low level, when you want to write something to a hard drive (whether it's a spinning magnetic platter, an SSD drive, a flash drive, or whatever), you're writing that data into numbered sectors. You say \"write data X to sector Y\", where Y is some number. \n\nThe file system translates that into a directory structure. So instead of saying \"write data X to sector 41567\", you say \"write data X to file C:\\Users\\Username\\Documents\\myfile.txt\" (if you're on windows). File systems thus create an abstract structure around the raw data that's on the drive that allows the computer to function. The way it does this is incredibly complicated, but many file systems basically keep a sort of tree stored on the device, where each directory is a branch. When you need to access a specific folder, you walk down the branches of that tree until you find the sector you need to read from or write to. \n\nNow, many files are too large to store in a single sector. So, basically that file becomes a tree of it's own, linking several sectors (which does not necessarily have to be next to each other physically) together. When you write large files to a hard-drive, or copying over many files at once, the file system is continually updating this tree, moving links around and finding new sectors to to write to. \n\nHere's where the problem comes in: what if, for some reason (like you pulling out the usb drive), a write is unexpectedly cancelled in the middle of writing large amounts of data? Well, then, there is a large risk that this tree might get messed up, and when the tree gets messed up, data can disappear, sectors which should have been written to remains unwritten, and all sorts of bad things can happen. In other words, you DO NOT want to mess this tree up. What you have to do then is run special programs (in Windows it's called \"chkdsk\", in linux it's called \"fsck\") that repair the structure of the file system and restores whatever can be restored. These programs can take a long time to run, since they basically have to check the entire drive for inconsistencies in the file system structure. \n\nThis is a big problem, and you might ask whether or not we've come up with a solution. And the answer is yes, we have solved this problem with something called \"journaling\". Modern filesystems keep a \"journal\" of all the different changes it intends to do, and it keeps it updated both before and after writes have been done. So, when you yank out the USB drive, the journal will reflect what was and wasn't changed, so the next time you plug it in the computer can just say \"oh, wait, this part of the tree is messed up, but the journal contains all the information I need to repair it, so I'll just do that\". This happens automatically and completely transparently when a file system is mounted (i.e. made available to be write and read from), which is why modern computer users very rarely have to wait 30 minutes for a computer to start up because it has to check the entire file system (something which was common back in the 90's). \n\nNow, you may ask, if that's the case, do I need to worry about yanking out USB cords? And the answer is, I'm sorry to say, yes you do. The reason is that almost all camera memory sticks and USB dongles use an antiquated filesystem known as FAT32, which does not use one of these fantastic journals. The reason why everyone uses FAT32 anyway is that it is basically the only filesystem where there are built in drivers for it in every operating system, so it doesn't matter if you plug it in to a Mac or a PC running Windows or Linux, it's just gonna work. No need to install drivers or anything. \n\nFAT32 is terrible, terrible file system (there are many reasons besides the journaling thing, another big one is that FAT32 can't store files larger than 4 gigabytes), but it's the only one we've got right now that offers easy interoperability between operating systems. If you don't care about that, you should format your usb sticks to whatever modern file system your OS uses, NTFS for Windows, HFS+ for Mac, or ext4 (or a bunch of other ones) for Linux. Then you never have to worry about yanking stuff out, because all of them are journaled and your tree structure will never get messed up. \n\nIf you properly eject a drive before yanking it out, what happens is that the computer basically closes the connection to the file system (known as \"unmounting\" it), so that no more writes are possible. That way, you ensure that the structure on the device remains consistent. \n\n**TL;DR:** if you yank a drive out, you can mess up the structure of an unjournaled file system. To avoid that, either format the drive with a modern file system, or properly eject the thing every time. Or just make sure you're not writing anything to the disk when you pull it out, that basically works as well. ",
"As others have commented, cached unwritten data could be lost.\n\nHowever the reason windows complains about unexpected USB drive removal, is usually because some program has an open (read only) file handle. Could be windows explorer itself (are you browsing the drive) or an app like a photo viewer or media player. A well written app will be able to deal with \"sorry, the file disappeared so your read call failed\" but many would just crash. Windows can't guarantee that all apps are written correctly, that they would not crash if an open file suddenly vanished, so it tries to prevent users from pulling the rug out from under these apps.\n",
"If you have write caching turned on, writes will go unfinished. To get around this, disable write caching on all removable drives (you can find this in the drive's right click menu). This will force all writes to go IMMEDIATELY, but also handicaps the performance of the drive.\n\nSo it would still be possible ot rip it out while its writing data, but you'd be safe the second the file transfer box or file save completed.",
"Nothing happens. This is because since Windows 2000 or Windows XP, By default when you copy a file to a thumb drive, it's all written ASAP. \n\nIf you pull it out while you are copying files, then the files on the thumb drive will appear as corrupted.\n\nNothing more.",
"If you are ever wondering whether to chance the extra minute it takes to eject it or not, think about this. One time in college I wrote up a 10 page paper in a single day which was due on a Friday. I was actually happy with what I had written and the content of the essay, so I was super happy to be done with it before my birthday weekend. I save it to the usb, pull the usb out of the PC, run upstairs to the PC with a printer, only my usb drive was now corrupted and every bit of data was unrecoverable. I just turned my computer off and forgot about it for the weekend.",
"1) Any of the data that \"appears\" on the drive, might actually still be in RAM and not have finished writing to the usb drive. Unplugging it might interrupt a sync that is still in progress, and you lose data that only **looked** like it was on the drive. In linux, you can avoid this by just typing \"sync\" into terminal and wait for that command to finish before unplugging the drive.\n\n2) Also, any trash/recyclebin files won't be purged and the drive will eventually fill up if you keep doing this. Example: 4gb flash drive, the drive properties says there is 1gb used up, but nothing will transfer to it because \"it's full.\"",
"On FAT16 volumes, Windows would calculate the amount of free space by counting the unallocated clusters in the File Allocation Table whenever you ran DIR (see [\"A Brief and Incomplete History of FAT32\"](_URL_0_)). On FAT32 volumes, that took an inordinate amount of time so Microsoft created an entry in the volume metadata that tracked the amount of free space left. This entry is updated whenever the file system driver makes changes to the file system.\n\nUnless the volume is uncounted uncleanly (IOW, taking it out without ejecting it). In this case, all of the unallocated space is counted up and the free space in the volume is recalculated and rewritten to disk, which take minutes.\n\nFAT32 is widely deployed on USB keys, camera flash media, etc., which means that just pulling it out of the computer results in the free space entry becoming invalid.\n\nSo you could either eject properly and wait for the file system driver to write everything to disk then start using the drive immediate on the next insert or you can yank it out, hope everything was written properly and wait a minute for the file system driver to calculate how much free space is left on the drive.",
"Nothing unless something on your computer is actively using the device or data is being transferred. In that case some data may become corrupted from the interruption in the transfer.\n\nIt's a huge misconception that unplugging it without ejecting \"breaks something\"",
"I've been working on, building, and fixing computers for more than 20 years. Mac, Linux and PC. As long as there is no data transfer going on, I have only had one problem just pulling the device out.\n\nThe only thing that ever failed on me was a 12,000RPM drive that was supposed to be hot swappable. I think it had issues with being moved while at speed even though it was not reading or writing. Since then, I try to shut down media that is moving before I work with it physically.",
"It's a technical equivalent of walking up to a scribe and just stealing their paper. Most of the time they're not writing and everything is fine, sometimes they're midway through a paragraph and the information turns out a bit wonky (files in inconsistent state, filesystem with freed or double-committed blocks) and very occasionally they're writing at that time and you get the software equivalent of a pen strike across the paper (corrupted sector, checksum failures, file table corruption). ",
"Most of the answers seem to be talking about the effects to a filesystem. \n\nThat is only ONE of the reasons you should be careful about ejecting drives. \n\nThe other is that applications maintain various types of records about the files you work with using them. \n\nSay you add a new picture to a document. Internally it might have to do a bunch of operations to your file. \n\nWhat you see as, say a document - is actually a complex structure of several types of files internally. \n\nTake a Microsoft Word [DOCX file](_URL_0_). One that looks [like this](_URL_1_). A Microsoft Word DOCX file is actually a zip file, with a bunch of files within it. \n\nYou can extract those files, and get a list of the files it contains: \n\nHere's the list of files from my example document: \n \n \\[Content_Types].xml\n \\docProps\\app.xml\n \\docProps\\core.xml\n \\word\\document.xml\n \\word\\fontTable.xml\n \\word\\settings.xml\n \\word\\styles.xml\n \\word\\stylesWithEffects.xml\n \\word\\webSettings.xml\n \\word\\media\\image1.png\n \\word\\theme\\theme1.xml\n \\word\\_rels\\document.xml.rels\n \\_rels\\.rels\n\nIf you don't want to go read the full spec, no worries - Just looking around, you can make out what some of those things are. There's an image there in a 'media' folder, a 'document.xml' which contains the actual document text. \n\nNow, Word is pretty good about how it manages writes, and it shouldn't corrupt the file if the drive is yanked out. \n\nOther applications might not be so smart - they might, say, indicate they need to copy the image over - but not actually do it until later (because users complain that it takes forever to attach images). \nBut they'll update an index of images to say the file is there. Then something might prompt a save of the indexes, but not trigger the image to be copied over. \nSo, you'd have a reference saying \"Image here!\", with no image. A document version of a \"404 - File not found!\" \n\nSource: 12+ years software development and all the associated bugs with saving of data. ",
"You got lucky. \n\n* 1 Windows (or OSX, Linux...) are lying to users. \n\nWhen you copy data to a USB device, the system push it into the RAM (technical slang : a buffer), because its fast. That's what [this](_URL_0_) is not telling you. The end of the progress bar does not mean 'data has been copied on the device' but 'data copied to the buffer'. *sigh*\n\nThen, while you go back to using the computer, the system copies the buffer to the device in the background. Invisibly...\n\nHence the problem, the user has no clue about this, and even if he knows (you know now) he has no way to know if the buffer to device transfer is done. That's why the system requires an intermediate step, that is 'asking for ejection'. When this signal is pulled, the system will urgently push all the remaining data from buffer to the device and then tell you that it is safe to unplug that device from the machine.\n\n* 2 What else \n\nThey could do things differently, like having a list of USB device with little spinners, sand timers indicating, or color codes indicating which one has no more data to be sent to. ",
"Windows : Hot pluggable, just don't do it when there is a lamp flashing\n\nApple / Linux / Unix : not recommended to just unplug, the USB drive is mounted in the file system, however in the most cases, there won't be a damage.\nUSB Drive itself: their electronic is built in a way, that during the plugin the not avoidable \"unclear\" status does not cause negative effect.\nCompare to simple analogue electronic: a loudspeaker who is connected to an amplifier, which does not mute by relay, makes terrible noises when the amplifier is powered on or off.",
"On early XP, you'll most likely corrupt something. Whether it looked like it was in use or not. On XP (SP2+?) and later Windows it might only corrupt the files that are in use or being transferred at the time of removal.",
"It's just like cleaning your but after taking a shit without looking; You might have done it right or wrong, but you will only really notice when you look at it again."
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"http://en.wikipedia.org/wiki/Office_Open_XML",
"http://imgur.com/77TOscs"
],
[
"http://imgur.com/gbg7kwK"
],
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|
2iv3v6
|
Panzer tanks: "first-class visual and command facilities"?
|
I'm currently read Panzer Leader after /u/saelyre's recommendation. Guderian makes the following statement:
"*I have never regretted my insistence at that time on our tanks being equipped with first- class visual and command facilities. So far as the latter is concerned, we were at all times superior to our enemies and this was to compensate for many other subsequent inferiorities that necessarily arose.*"
What were visual and command facilities? Were they in fact superior to those of their enemies? Did they allow then to "compensate for other subsequent inferiorities"?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2iv3v6/panzer_tanks_firstclass_visual_and_command/
|
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"text": [
"On a purely technical level, \"visual and command\" references both German radios and optics. Although German tank design was relatively conservative, especially at the start of the war, their tanks incorporated good optical equipment and effective radios. The latter was especially effective at coordinating German panzers as an effective unit. German optical sights were often quite advanced as well. This gave the early war German tank commanders a better sense of situational awareness than his French, British, or Russian counterparts. \n\nBut the Germans' early superiority in situational awareness was not just of a technical nature. Most German commanders did not fight \"buttoned-up,\" which is tanker parlance for fighting inside the vehicle. At the top of a German turret was an circular armored cupola with vision ports all around it. This allowed a commander to scan terrain with the \"Mark One Eyeball\" from a [relatively safe position](_URL_0_) as seen in this photo of a Panzer IV. Early war Allied tanks did not have this ergonomic design. For example, the [earlyT-34's top hatch](_URL_2_) was notoriously clumsy and did not give the commander a good view and exposed him to fire from the rear and flanks. When the Germans captured Allied tanks, one of the first things they would do if able was replace the top hatch with a German one, as in these [*Beutepanzers*](_URL_1_). \n\nSo in sum, not only did early war panzers possess better optics and radios, they were a more ergonomic design than their contemporaries. \n\n*Sources*\n\nForczyk, Robert. *Tank Warfare on the Eastern Front*. Barnsley: Pen & Sword Military, 2014. \n\nZaloga, Steve. *Panzer IV Vs Char B1 Bis: France 1940*. Oxford: Osprey Pub, 2011."
]
}
|
[] |
[] |
[
[
"http://panzerfaust.ca/AFV%20interiors/pz4d_files/pz4h-01.jpg",
"http://beutepanzer.ru/Beutepanzer/su/t-34/t-34early/t-34_camo_01.jpg",
"http://www.asisbiz.com/Battles/Barbarossa/images/Soviet-T-34-tanks-abandoned-after-a-battle-with-German-forces-01.jpg"
]
] |
|
5or7wg
|
why do competitions require you to answer a ridiculous question when you enter?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5or7wg/eli5_why_do_competitions_require_you_to_answer_a/
|
{
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"Well, in the UK a competition with a question is regarded legally as a game of skill, even if the question is stupidly simple. Without a question it would be regarded as a lottery, which has very much tougher rules and regulations.",
"Well, without any indication of what you consider a \"ridiculous question\" it's going to be hard to know what the best answer is. \n \nThat said: Contests have to take care to not be treated as illegal lotteries. There are two ways to do this: \n1) Make the contest free for anyone to enter (e.g. \"no purchase necessary\"). \n2) Make the contest include a 'skill' component. Asking a question meets this standards. "
]
}
|
[] |
[] |
[
[],
[]
] |
||
9mzp5a
|
what is treasury yields and why does it cause the market to slide?
|
What does it mean when the news reports that US Treasury yields?
What's the Treasury's relationship with the market that causes it to slide over the week?
I've tried to read up about it, but it just gets more confusing. I was surprise to find that there are 3-month US treasury, 1-year US treasury, 2-year treasury, and so on. What are they?
The one that has gone up recently is the 10-year treasury. Why that 10-year treasury but not other intervals of treasuries? And why does that 10-year treasury have such impact to the market?
So there so many questions running in my mind. It will be great if someone can explain this to me. Thanks!
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9mzp5a/eli5_what_is_treasury_yields_and_why_does_it/
|
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"First all the quick answers:\n\nTreasuries are US government debt. Yields are how much interest the US government will pay lenders to loan money to them for a certain period of time. 10-year treasuries are the long term benchmark rate, they're the bench mark because they're a very liquid market. All the other rates are just different terms (pretty similar to a 3-year, 5-year, or 7-year car loan) the government can get more money for less interest by offering a variety of terms. \n\nNow the why:\n\nTreasuries are like the basic unit of investing. The US government has a very good reputation with investors, so treasuries are the safest return one can get over a period of time. \n\nThat means that when treasury rates rise, all other investments need to adjust (because if riskier investments don't provide at least that much return, investors are better off selling the other investment and buying the treasury). Sort of like an employer known to hire essentially everyone paying more than other more selective employers, the selective employer is going to have to keep their wages higher than the employer who hires anyone if they want to keep getting employees. \n\nSo when treasury yields rise, all other investment income rates also have to rise, and that means most investment prices fall. ",
"The National debt that you often hear about? That is the result of the government selling bonds to investors. The government collects money now, and agrees to pay it back down the road with interest.\n\nThese bonds are called Treasury Bills, or T-bills. The yield is the % of interest they pay out to buyers. The time frame is how long the money is loaned for, ie. a 10 year treasury gets paid back after 10 years. The longer the timeline, the higher the risk that things like inflation will counteract the interest gains, so longer term bonds pay a higher interest rate then shorter ones, where the external risks are better known. An increase in yield means that an investor get more money for the same (super low) risk investment.\n\nIf, as an investor I have the choice of low risk 2% return or higher risk 5% return, I may be more likely to take the higher risk. If the low risk option pays 4% vs. high risk 5%, I am a lot more likely to choose the safe option. So I might sell high risk stock and buy low risk T-bills instead. Less demand for stocks (more sellers than buyers) causes their price to fall.",
"Some of the other comments have glossed over what yield actually is, and why it rises/falls.\n\nA bond is a special kind of fixed interest loan where you borrow some money, pay interest only for a number of years, then pay back the full amount of the loan in one single final payment. For example, the US treasury takes out a loan for $1000 over 10 years at 1%pa interest. They pay back $10 (interest) each year, then after 10 years, they pay back the full $1000.\n\nWhat if you lend the treasury $1000 for 10 years, then 2 years later you need that $1000 back? Treasury won't give it back early, but you can sell the loan to somebody else. You might find someone willing to pay you back the full $1000. That person will then get the remaining $10 yearly payments and the final $1000 payment. From this person's point of view, they have lent the treasury $1000 for 8 years at 1% interest. \n\nHowever, maybe you can't find anyone willing to pay back the full $1000. So, desperate for money you agree to sell the loan to someone who will only pay you $900. However as the new owner of the loan, they are still entitled to the full $10 annual payments and the full $1000 final payment. This is basically the same thing as earning a higher rate of interest. In fact, from this person's point of view, they have lent treasury $900 for 8 years at something closer to 2.5% interest.\n\nThis effective interest rate is called the yield. It matters because anyone wanting to sell an 8 year treasury bond at the same time as you are trying to offload your one must offer an effective interest rate equal to 2.5% to compete with you. Especially, even the US treasury won't be able to sell new bonds for 8 years unless they offer an interest rate of 2.5%.\n\nThe yield is a reflection of how willing people are to buy \"second hand\" loans at any particular time. \n\n"
]
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[] |
[] |
[
[],
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|
48e5e1
|
why does urinating feel different when you are sick?
|
Can tell I'm a sleep out from a full blown flu and possibly. Today had some minor symptoms such as stuffy nose and sore throat with the general body ache that comes with a flu
When urinating it feels almost more sensitive/different, don't really know how to describe
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/48e5e1/eli5why_does_urinating_feel_different_when_you/
|
{
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5
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"text": [
"For a multitude of reasons, among them:\n\n+ When sick your system is generating different chemicals from the immunologic system fight, which generate different contents, pH and even smell for your pee, the different contents and pH can irritate the urethra and be painful\n+ Your sensibility usually is higher due to the disease, so you can not only feel more intensively the urine pass, but also the above mentioned irritation\n+ Your urination frequency messes up due to the sickness and you end up going to the bathroom at unusual (for your normal daily routine) times, which can also feel different"
]
}
|
[] |
[] |
[
[]
] |
|
3wuokw
|
why did sega drop out of the video game console business?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3wuokw/eli5_why_did_sega_drop_out_of_the_video_game/
|
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"Because people stopped buying them.\n\nThere is an apocryphal story that Sony released a *Final Fantasy* game the day of the Saturn's release, in a move to deliberately cripple sales of the new system.",
"The fact of the matter is, they lost.\n\nThe Nintendo sold in much higher numbers than the SEGA master system then the Super Nintendo outsold the Genesis. Now, someone has to be number 2, so SEGA was OK. Then came the next generation and the entrance of Sony. The orginal PlayStation did better than SEGA's Saturn and then the following generation the Dreamcast was simply slaughtered by the PS2, despite having a 1 year head start. And that was the end of SEGA making consoles. \n\nAt first Nintendo and SEGA were fighting for position, and SEGA lost. Next thing you know they lose again, then the real fight is between Nintendo and Sony and SEGA is simply left on the sidelines. There's really only enough console market for 2 players in the hardcore gamer space. Nintendo and SEGA, Nintendo and Sony, Microsoft and Sony. The only reason Nintendo still survives is that they stayed with the younger gamer target market when Sony and MS moved to older rated games.\n\nEven today Nintendo struggles to be a third console maker and that's only because the system is radically different than the top 2.\n\nThe second thing to understand is that home consoles were always a secondary revenue stream for SEGA. They started as an arcade company and that division was still profitable while the dreamcast was burning money like mad.\n\nThey made an businesses decision to remove themselves from that market. The same thing Nintendo could easily decide to do today, shift all it's attention to the handheld market and just walk away from home consoles. \n\nSega left the market because they lost. They could of kept throwing money at the pwo ",
"Sega spent a lot of money making the dreamcast. They didn't get enough money in return. They decided they can make more money with software alone. Big reason being, the market is too saturated with giants with a lot more financial backing then sega will ever have. That said - Dreamcast is still my favorite and I can't wait to play Shenmue 3... finally... ",
"SEGA made some pretty dumb decisions back then. The company created two \"add-ons\" to the Genesis: SEGA CD and the 32X, which didn't sell very well. Besides, the next console they made was the SEGA Saturn, which also didn't have very good sales, in fact, they were horrible. \n\nAnd the final nail in the coffin was the Dreamcast. It had potential, *BUT*, due to the small library of games, not many people bought it. Because of all of these failures in the console market, SEGA became a Third Party Company.",
"They were in rocky waters and the dreamcast was their last shot. The lack of killer apps( there were great games just not great selling games) + the ps2 dropping was the nail in the coffin for Sega as a console maker. They spent a lot of money on that venture and lost big time.",
"I happened to work for a competitor to Sega during that time. Sony changed the game when the Playstation came out. Then Microsoft followed with the Xbox. BOTH Sega and Nintendo were unable to compete with both Sony's and Microsoft's ability to sell at steep losses for extended periods. They simply didn't have the cash reserves to do this.\n\nSega simply bowed out. They said \"no thanks\" to selling hardware at such steep losses. Nintendo interestingly did not - it was actually expected that they would. Nintendo came back with a very innovative approach. They let Sony and Microsoft duke it out for the gamers' first hardware choice - they made sure they would be the second. So gamers tend to have a Sony OR Microsoft console and a Nintendo console. They succeeded surprisingly well here. It is not the type of move Sega could have made. Sega always competed with high end hardware. They were very successful here with Genesis. \n\nNow.. there are plenty of things Sega lost/failed at as others have mentioned. They did actually learn from their mistakes - the Dreamcast was a fantastic machine. The Dreamcast (and Sega) just never stood a chance of competing against Sony and MS. Sega did the right thing in bowing out BEFORE failing. It is actually one of their few good decisions and the reason why they still make games. Some are even pretty good.\n\nEDIT: I say that with the Dreamcast being my favorite system of all time and with its cancellation being rather heartbreaking. Yet.. it was the right decision.",
"I lived through it, the SNES versions of the same games cost less and had more levels than the same games on Genesis. Sunset Riders was my favorite game on Genesis and when I played it on my friend's SNES, it has about twice the content and I found out it was $10 less at the same store I got the Genesis version. Our wealthy friend had a Neo Geo that was fucking mind blowing, but it cost way too much for a game system that could only play games (there was no media center or DVD playback back then). Neo Geo lost early on volume. Sega got a reputation as being not as good as SNES. \n\nThat's when Sega started doing that bullshit X32 and whatnot add-on death spiral. Now your parents could buy you a game for the Genesis and find out it doesn't work because they didn't get this crazy add-on and they would tell their friends not to get their kids a Sega thingy. Sega never learned and would keep doing this shit like grown people were playing their consoles back then. It would be a cash cow now, like physical DLC, but not back then. Their add-on crap wasn't doing the trick, so they upped the anti.\n\nThe Saturn blew the SNES out of the water and supported 16 players at a time when the average TV was below 20\" and in standard definition. If you find an old Saturn with the splitters, controllers and bomber man, you can have a great time on a new big screen. My wealthy friend had a Saturn and we did bomber man at a party with 16 player and it was awesome (so awesome that at one point in college I purchased a Saturn, 16 controllers, the splitters and Bomber man and ran a tournament with cash prizes). The problem with Saturn is it only had a few really good games and not much when it released (the flagship game, Nights into Dreams, was lame). PlayStation came out the same year as the Saturn and had better game offering that weren't centered around 16 people squinting at a 2 inch square section of a TV to be cool. Neither was so much better than the SNES that Nintendo was threatened. Sega was second fiddle again, this time to a nobody in the form of Sony.\n\nN64 was revolutionary and came out a few years after PlayStation. PlayStation had already made a name for itself in an unbelievable way (more than half the market by then) and Nintendo had to step it up to compete. Sega and PlayStation were too close to their last releases to respond and Nintendo cleaned up for a while. PlayStation responded with new games for it's market dominating platform, Sega Saturn had flopped, so it had no response but to double down on the next release.\n\nDreamcast was nuts and came out a few years after N64; it sold like hot cakes for a few months on hype that it was a PlayStation killer. It had some good games, but not enough and PlayStation fired back with PS2 and host of amazing games and DVD playback. That was it. Everyone that bought a Dreamcast wished they had bought a PS2 and no one bought any Dreamcast games. Sega lost their ass because they had loss lead the console, but made tons of money on games for other platforms and they gave up on the console business.",
"I read about Sega and Nintendo in the book [The Console Wars](_URL_0_). The book does a good job of telling how Sega of America (SoA) did the impossible job of taking the console fight to Nintendo, and through some genius marketing was able to take majority market share with the Genesis. However, according to the book, the Genesis never really took off in Japan like it did in the US because the Japanese executives did not want to follow SoA's sales strategies. The book really makes it seem like Sega of Japan (SoJ) really held a grudge against the American office and started to actively fight against their ideas. IMO, the biggest mistake Sega made was when the SoA President found a company making an incredible next gen processor that he wanted to use in the Saturn. For petty reasons, SoJ didn't want to use it. Feeling guilty for getting the processor company's hopes up, the SoA President had them call up a friend of his at Nintendo. That processor became the technology in the Nintendo 64. Had that processor actually been used in the Saturn, I bet Sega would still be around. \n\nThe horrible launch of the Saturn was just one of many missteps caused by the friction between SoA and SoJ. It seems to me that the inability for the two offices to work together was the real reason Sega failed at the console market.\n\nTL:DR: IMO, Sega failed at consoles because Sega of Japan office didn't want to listen to any advice or work together with Sega of America.",
"OOH! I got this one!\n\nFirst, it is important to know that in the beginning, Sega was primarily a arcade developer. \n\nAs they made games and hardware, they made a home console, with strong 1st party support. The Genesis blew the NES, and \"Brought the arcade home\". It was super popular for a time. \n\nThen the Super Nintendo came out, and we had the first big Console War, (the likes of we wouldn't see again until the PS3/360 era.)\n\nIn the end, Sega took a mild loss. The 32 Bit era was about to start, so Sega, unsure what to do, gave Sega of Japan and Sega of America a project to make a 32 bit system. SoJ made the Saturn, SoA made the 32X. The 32X was a 32-Bit add-on for the Genesis, that could do some nice things, but nothing near the Saturn. Still, it robbed Saturn of sales, and was a terrible failure. This lowered confidence in Sega.\n\nWhile this was going on, Nintendo had really strict censorship rules, and Sega's laxness made it the \"edgier\" of the two. \n\n32-bit era begins, this time with a new challenger, Sony PlayStation. Sony doesn't have Nintendo's censorship, and the PlayStation is much easier to program for than the Saturn. \n\nThe issues with the 32X, and lackluster starting library hurt Saturn in the beginning, and Playstation kept the hurt going. \n\nSega got the bright idea to launch a next-next gen system (Dreamcast), before the public/industry was ready to upgrade, and was full of features like Online Play, that didn't have the necessary tech to pull off well. \n\nOnce the PS2 and the Xbox came around, the Dreamcast went from looking cutting edge, to looking like the Wii. \n\nThe fact it could play burned games out of the box didn't help revenue either. \n\nAfter having 2~3 systems in a row die hard, Sega went back to doing what they did best, make games. \n\nAs an aside, the slow death of Arcades contributed to the slow death of Sega, as their IP's were less and less in the public's eye. ",
"Because their last two consoles flopped, at least, in the US market.\n\nSaturn was doing well in Japan, but the US division made a really, really stupid move by suddenly releasing the Saturn early without telling anyone. This pissed off retailers who weren't ready to sell it yet, some even going so far as throwing out all their Sega merch and replacing it with Nintendo/Sony stuff. It also pissed off developers who didn't have their games ready yet, because they were not told about the sudden early release. The Saturn flopped really, really hard in the US.\n\nDreamcast did okay in the US, but was just horribly overshadowed by the PS2. With PS2 and now Xbox entering the market, Sega focused on just making games for the Dreamcast to try and ride out their remaining time before the PS2 released. After PS2 and Xbox released, they just rode out the rest of Dreamcast's life and decided against making any future consoles.\n\nI suppose you could say it started as early as the Genesis addons, which both failed pretty hard as well. The CD sold *okay*, but the 32x just sold horribly.",
"This might be a bit more lengthy but I do think G4's Icons documentary on the Dreamcast gives a pretty good explanation of how Sega left the console game if you want to know more.\n\n_URL_0_ ",
"Sega had difficulty selling their later consoles. People stopped buying them, so companies didn't want to make games for them. It reached a point where it didn't make sense anymore to make consoles. But people still loved games Sega made, so instead of selling a limited number of great games to a small number of console owners, they decided to make games for wider audiences on other companies consoles. ",
"As usual. The top comment is wrong. Oh well... There was a lack of unity between different parts of Sega. Sega of Japan had a different vision than Sega of America. (there are more divisions of Sega than just those two) There are a few books that talk about this and there are many sources on the internet that will tell you. But yes the top comment is completely wrong.... But essentially the big problem is that with no unity. Pieces of Sega were all doing their own thing. This is why Sega CD came out followed quickly by 32x. And then there was the Sega Neptune that never saw light of day. And finally the Saturn which was a technological mess because it was hard to develop games for 2 cpus and it was also incredibly expensive. (Saturn was like $400 console which is like an a $644.20 console today) 4 pieces of hardware being developed in rapid succession... The Dreamcast was a step in the right direction, however the company burned far too many bridges with a failed Sega CD, 32x, and Saturn. All of this information you can verify by searching the internet and/or going to the public library. I really wish people would stop up voting non-sense. Argumentum ad populum... This question doesn't even need to be asked. It's easy to look this information up yourself.",
"Because Sega had released the Dreamcast and in doing so created the perfect video game system. Sega would never surpass what they did and knew they should leave the console business while they were on top.",
"A lot of people aren't explaining WHY the Sega consoles sold poorly compared to their competitors.\n\nThe answer is that almost every Sega console had a slew of underutilized functions. For example, the Sega Genesis had online multiplayer capabilities built into the hardware, but none of the games released in the United States had online multiplayer MODES. It was expensive to test, and very few people had internet at the time, most of the games for the Genesis were developed to be ported to multiple consoles, and it didn't increase the sale value of the cartridge, so most developers didn't bother.\n\nSo customers had to pay more for a Sega console because it had a bunch of functions... that they couldn't use. Nintendo consoles cost a lot less, and had roughly the same quality of experience.\n\nThe cost-to-functionality ratio is the same reason the Xbox broke into the market.",
"A lot of people are only viewing this from the Western market perspective. Sega's hardware is very much alive, at least in Japan. If you walk into a game center (the arcades), the majority of the arcade machines are made by Sega, as well as the pseudo-gambling machines. I never go to a pachinko parlor but I wouldn't be surprised if a decent chunk or more of them are made by Sega. They also have UFO catcher machines (claw machines) and other entertainment devices.\n\nAlso the Dreamcast that many people are citing as a the reason for their failure had a larger library and better reception in Japan. To me, it just seems like Sega decided to stay domestic while Nintendo and Sony aggressively fought for the international market. I'm sure Sega makes a pretty enough penny with essentially every aspect EXCEPT for home consoles, that they don't really need to care about it to make coin.",
"But also aside from the dream cast sega fucked up on the 32x, sega CD, game gear and the saturn didnt win either. They made mistake after mistake",
"Because they were bad at console business. Let me explain. \n\nSega had a horrible reputation of not supporting their consoles. They would build something and then ignore it. They would move onto the next project while developers scrambled to get content out for the system. So while developers were pushing content for Genesis, Sega was releasing Sega CD. Sega CD was out for 3 years before being discontinued. In those 3 years, Sega developed and released the 32X. \n\nThis addon required developers to switch gears and develop for it instead of the Genesis or the Sega cd. Even though these were addon accessories, they still pulled development away from the original system. The 32X came out shortly after the Sega CD and was out for 2 years before being discontinued. \n\nThe reason they were discontinued was the release of the Sega Saturn. This required developers to quickly switch to the new console and essentially wasted tons of development time to the previous addons that could have been used to develop for the Saturn. \n\nThe Saturn was released in 1995 and discontinued in 1998 the same year as release of the Dreamcast. \n\nThese years are all NA, below is JP. I bring this up because the 32X and Saturn debacle is really the answer you seek. The 32X was under promised and ended up being much better than they anticipated. It was announced around the same time the street date for the Saturn was announced. This caused marketing problems and they ended up marketing the 32x as a transitional product aimed at people who couldn't afford the twice as expensive Saturn. This caused the 32x to sell out. In fact, more people wanted the 32x than the Saturn so eventually Sega discontinued it to focus on the Saturn. Doing this left developers out in the cold. 32x and Saturn games were not compatible. The quick release of the Dreamcast gave developers pause. They just went through all of this and most were not eager to relive the experience. Thus the developers did not follow Sega to the Dreamcast. This combined with the Sony Onslaught is why they stopped making consoles. \n\nA quick timeline. \n\n- SG-1000 1983. \n- MasterSystem 1985. \n- Genesis 1988. \n- Sega CD 1991. \n- 32X 1994. \n- Saturn 1994. \n- Dreamcast 1998. \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n",
"Sega challenged Nintendo at the height of its power, directly and very aggressively. The Genesis/Mega Drive made the videogame market truly competitive for the first time in years. The NES was clearly inferior and Sega had about 2 or 3 years to enjoy being the cutting edge (unless you count the NeoGeo and I don't). \n\nThen, along comes the SNES and the era of the Radical Mascot games, which Sega basically started with Sonic the Hedgehog. This helped Sega compete, but now the shoe was on the other foot: The Super NES had better graphics, much better sound and a lot of amazing games. Sega's head start was becoming a liability by 93 or so. Fighting games, primitive 3D and FPS, and even JRPG games were exploding in popularity and the SNES was the console better suited for them, for a variety of reasons.\n\nSega comes to believe that the key to regaining the initiative is to regain the technological advantage. First, there was the Sega CD. whereas Nintendo and their loyal devs were more or less defining the near-term future of video gaming, Sega, like many others at the time, bought into the idea that barely-interactive movie/games were going to overwhelm everyone with visuals that the SNES couldn't match.\n\nThat being an expensive failure, the next step was 32 bits. It's twice as many! Unfortunately, the first attempt at that was the 32X, another expensive Genesis add-on. It had few games and fewer good ones. And then, just one year later, Sega was asking people to lay out 400 more $mackeroos for ANOTHER 32 bit machine. You can imagine how that must have felt to 32X owners. Sega actually intended, from the start, to market the 32X as a 32 bit bargain model and the Saturn as the flagship console.\n\nNever one to say no to a terrible idea, Sega released the Saturn with no warning, literally. Tom Kalinske of Sega of America was expected to show the console at E3 1995. Instead, he announced that it was already for sale,in limited quantities, at select retailers, for $399. This was done at the behest of Sega of Japan, to give the Saturn a head start (of four months). All this accomplished was surprising gamers, infuriating all the retailers (big ones like WalMart) who were not informed by Sega or included in the early distribution and, in some cases, retaliated by refusing to stock Saturns and games. Sony immediately follows that announcement with one of their own, about the Playstation: \"$299\". Saturn was dead by 1998.\n\nSo, after some big shakeups at the company, the Dreamcast comes out at the very end of the decade, and Sega seems to have finally gotten their shit straight. It's cheap, the games look amazing, there are a lot of good and unique titles very quickly, and it largely delivered on its promise to be the first console to emphasize online gaming. And it had the terrible luck to debut just ahead of what would go on to be the most popular console ever.\n\ntl;dr: Sega went full retard and snapped out of it too late to save itself.",
"It's really too bad, for a number of reasons, but primarily because House of Pain really went to bat for them. \n \nAlso, Sega had the best commercials.",
"The simplest explanation is that Sony took Sega's market in the console wars. Sega was always a bit more rebellious than Nintendo when it came to mature audience games. When Sony came along it took that market.",
"They made too many consoles in short spans of time that failed. Consumers lost trust in them. In a short period of time, they launched the Sega CD, 32x, then surprise launch of the saturn that retailers werent even ready for. 3rd party developers didnt even have games or dev kits for the thing. They jumped ship much like they did with the wii u. The saturn was underpowered when it came to 3D and that was where gaming was headed with the arrival of the playstation. Dreamcast was their attempt to make things right with consumers and 3rd party developers. It almost worked, but ps2 came and was more powerful and had the sony name behind it at that point. Even though the ps2 launched horribly it still killed the dreamcast. Sega bowed out and went software only. Long story short, sega killed themselves by flooding the market with too many systems that were weaker and more expensive than the competition and pissing off their fans and developers.",
"Anyone else play the heck out of Phantasy Star Online? I had a close knit group of friends in middle school who played this game with me until there wasn't much more to accomplish... probably the most fun out of any mmo I've played.",
"Because thats what you do when you make the greatest platform of all time. You retire a champion ",
"To get to the other side?",
"Basically the failure of the Dreamcast. I highly recommend [The GamingHistorian's video on the Dreamcast](_URL_0_), if you're interested, but to summarize, there are at least three main reasons for the Dreamcast's failure (summarizing GamingHistorian): \n\n1) the PS2. It was a much more powerful console---period. Also, it had a DVD drive while the Dreamcast still used CDs. The XBOX and Gamecube didn't help either. Sega just came late to the nextgen party with an all-around weak system (although it did have some revolutionary technology, like the memory card screen and online play)\n\n2) Lack of third party support for games. This was due to the failure of the Sega Saturn, which had a similar \"too late to the party\" story, so third party developers---especially big ones like EA---weren't too keen on developing games for the Dreamcast. \n\n3) Game piracy. When the Dreamcast came out, CD burners were getting quite popular too, and so people figured out how to rip games and turn them into images that could be read by the dreamcast. \n\nAgain, the video in the link above is highly recommended. ",
"Anyone remember how easy it was too play copied games on the dreamcast? None of the pain of physically modding the system. Just a boot disk then bam! Crazy taxi",
"I'm a guy who never got into video games, but I can't see the name Sega without hearing it as \"SEGA!\".\n\nWhy is that?",
"Love how all the top answers fail to mention buyers pirated the shit out of Dreamcast games.",
"It was meant to be. Sega was on the path out of the console business from early on.\n\nTheir first console, the Master System, had several incremental \"upgrades\" and I believe on the third try it finally found some success at competing with the NES. However, before there was even really a firm idea of \"console generations\", they released the totally different Genesis / Megadrive, thinking that more accurate arcade-to-home games would give them to ability to beat the NES. \n\nThat turned out to be their fatal error - the Genesis came out 2 years before the SNES, and Nintendo made their console significantly more powerful. Sega's system had enough traction by the SNES' release (with the help of Sonic, smart advertising, and continuing domination of then-thriving arcades) that it was almost an even battle. Yet, Sega had an inferiority complex and wouldn't rest with weaker hardware. \n\nCartridge-based games sometimes had extra chips in them to supplement the hardware's graphics and sound processing. But they added to the cost of each game, and it was redundant to sell the same extra hardware that could only be used with each game cartridge. So Sega basically thought they'd save the customers money in the long run by creating a peripheral 'supplemental console', the 32X, which would turn the Genesis into a more advanced machine than the SNES. Now, even in 1994 when it was released, there was still no firm concept of a 5-7 year console generation - consoles were being released every year, and even consumers didn't know how long a console \"should\" last for. That said, even Sega knew by the time the 32X was released that it was DOA. The 'Ultra 64' was on the horizon, which brought with it gamers' expectations of powerful 3D gaming at home. People who bought it felt duped, and everyone else was made more wary of Sega's offerings. (Others have simply mentioned the Sega CD and 32X in the same breath, but they were very different - the Sega CD actually lived for 4 years or so and did what it was advertised to do. It had nowhere near the negative impact the 32X had.)\n\nThe Saturn was successful in Japan, but a flop elsewhere, mostly due to Sega ignoring consumers' attitudes towards them post-32X. They made no effort to win back disappointed buyers, and without the enthusiasm of a core fanbase, they had a real uphill struggle. Add to that, they were selling the Saturn at a price point which was not competitive at all, and didn't even have a 3D Sonic game, which is what casual fans had been expecting to see.\n\nWith the Dreamcast, they released what the Saturn should have been, but faced a new set of challenges they were unprepared for. Sony drove up consumer expectations of what the next generation would look like, to the point where people thought the graphics would look like the CGI cutscenes in FF7, but in real-time (to be fair, very late PS2 games did have extremely impressive graphics). Dreamcast's graphics were clean, sharp (480p, a resolution that is *still* in use on the few Wii releases trickling out), and on par with even the most advanced arcade games of the time. Yet, gamers wanted more. Sonic still looked like a game, not CGI. Dreamcast was selling better than the Saturn, but not well enough. With MS' announced entry into the console wars, they knew they had no more tricks up their sleeve. The trajectory they had been on since the Megadrive had played out, and they landed back at being a games company.",
"Actually the reason was all the good game developers were jumping ship to go to the upcoming Xbox as well as the PS2, so they decided to scrap the hardware division and stay with game development.",
"What?!!! OMG, when did this happen?!",
"There are two main reasons. One, there was a clash of cultures between America and Japan. Japan would develop the games, and America would market them. Japan became offended when its American counterpart suggested what games needed to be developed. Japan developed its own games, which were quirky, and difficult to market to American audiences. It wasn't so bad during the Genesis era because there were so many games, but the clash just got worse and worse during the Saturn era. By the time of the Dreamcast, it didn't matter that SEGA had reinvented itself and had the superior machine on the market.\n\nThe second reason was market oversaturation. With the Genesis and Game Gear, SEGA had enough of a market share to chip away at Nintendo's monopoly, and developers were grateful for the benefits of the free market. But then SEGA alienated its base with too much hardware. The SEGA CD and 32X weren't next generation, but they weren't first gen either. They were placeholders? While SEGA was between systems, promising that it would support the SEGA CD and 32X, the Saturn dropped. And it dropped in such a way as to not only alienate consumers, but also retailers--only certain retailers were authorized to sell the Saturn. So if you bought a 32X for Christmas, it was dead by March. Japan fired its American CEO and marketing team to ensure that SEGA's machine would never find an audience.\n\nThen, of course, the PSX drops, and Saturn never catches it. Those who are saying that it was the Dreamcast are wrong; SEGA died well before that, during the Saturn years.",
"1. The Sega Genesis had too many add ons that weren't all that great. (Sega 32X and Sega CD)\n\n2. The Sega Saturn was released early causing backlash from retailers and some even refusing to carry it. It was difficult to program for. It also did not have a native Sonic title.\n\n3. The Sega Dreamcast did not have a DVD player. At the time Playstation 2 was actually one of the cheapest DVD players on the market. (This is one reason I could possibly see Nintendo dropping out at some point. It's 2015 and we cant watch DVDs or Blurays on the Wii or Wii U)",
"Real reason. Sony and Microsoft are both multi-billion dollar corporations. Their consoles don't need to make money for the company to remain profitable, because they make money in so many other ways. Sony can finance the Play Station through their film or television divisions, or vice versa. Microsoft can finance through anything. Sega doesn't have that luxury, and the profit to risk involved in consoles was too high. Nintendo on the other hand has found a niche with \"interactive\" games, and they have a great list of proprietary games and characters, allowing them to remain profitable, albeit not as profitable as Sony or Microsoft. ",
"Sega's management was pretty screwed up throughout the '90s. While Nintendo was focusing on continuing to make great games for the SNES (supporting the console well into the decade with hits like Super Metroid and Donkey Kong Country), Sega was churning out hardware without real purpose.\n\nFirst the 32x and the Sega CD, with both technologies being \"the next big thing\" in gaming but neither with the library to back it up. Then the Game Gear with its \"console-like graphics\", monstrous size and ridiculous battery autonomy. The Saturn was released ahead of schedule so it could beat the PlayStation to market, surrounded with poor communication with the audience and even the game developers. Finally, the DreamCast, the one hardware since the Genesis that showed real promise, landed with a thud amidst the popularity of the PlayStation (and the N64) and hype for the PlayStation 2.",
"Sega had a few flops in a row.\n\nThey tried to push additional life out of the Sega Genesis just before the Saturn released with the 32x. The 32x was way cheaper than any of the independent consoles, but it wasn't really that much of a leap. They launched this just before the Sega Saturn as well, which wound up hurting the Saturn's sales.\n\nThe Saturn itself was technically the most powerful console of that generation, but it was so damn convoluted to write games for that most developers never took full advantage of it. Meanwhile, Sony's Playstation was more or less the same hardware as Namco's System 11 arcade cabinets, so more developers were familiar with it from the get-go.\n\nThe Saturn pretty much flopped, and for Sega to have remained in the console business after those flops the Dreamcast had to be wildly successful. Unfortunately, it simply didn't measure up enough to keep them in the game.",
"After their highly successful 16bit console, the Genesis / Megadrive, Sega decided to make a 32bit console next, called the Saturn. The Sega Saturn released in September 1995. \n\nSony had just entered the games console industry with their 64bit PlayStation the same year. Because of this, Sega's main competitors at the time, Nintendo, decided that they would skip the 32bit generation and instead focus development on their own 64bit console, which we came to know as the N64. It released in June 1996, less than a year after the Saturn, and an entire generation ahead in terms of tech (at least that's what consumers thought anyway, 64 > 32). \n\nSeeing that they were being left behind, Sega had to quickly focus their efforts on producing their own 64bit console, which would come to be known as the Dreamcast. This resulted in them abandoning the Saturn early, which subsequently had a very short lifespan of under 3 years, as games ceased to be produced for the Saturn in 1998. The console was considered a disappointment by consumers.\n\nUnfortunately, Sega was not able to finally ship their 64bit Dreamcast until late November 1998. 3 years after the Playstation entered the market, and over 2 years since the N64. By this time, both Sega's competitors had estabished games libraries and fan-bases, and Sega found themselves unable to compete. \n\nThat, coupled with the fact that the Dreamcast suffered from rampant piracy, led to Sega withdrawing from the games console industry, after two successive systems being considered large failures. \n\nEDIT: Dreamcast was in fact 128bit, looks like Sega tried to put themselves a set ahead of the competition, but unfortunately it was too little, too late. Consumers did not trust in Sega's claims to have superior hardware after the slew of low-quality hardware failures (Sega CD and 32X expansions for the Genesis, the Saturn, and the canceled Neptune) in the preceding years.\n\nThat's a breif breakdown of events, anyway. Not that anyone will see this comment since it will be drowned below 1000 others.",
"Because staying in the console industry simply wasn't profitable enough, the genesis was huge nothing after was even close, to the point of mostly being \"failures\" from a profit perspective.\n\nThe CD did okay (approx. 2.25 million units.)\n\nThe 32x did less okay ( > 1 Million units.)\n\nBut those were just add ons so sega tried a new console \n\nThe saturn did poorly (approx. 17 million units.)\n\nThe dreamcast did even worse (approx. 9 million units.)\n\nUltimately they just couldn't beat their competitors, namely the ps1 selling 102 million units by the end of its run, and then just a year after the dreamcast's release the ps2 came out selling 155 million by the ens of its run. \n\nSega could have made another console but it just wouldn't make sense profits wise.",
"Remember when biggie smalls was bragging in his songs about owning a Super Nintendo AND a sega genesis? Pepperidge farm remembers.",
"A combination of factors really.\n\nBefore the Dreamcast Sega was supporting, in different regions, the Sega Saturn, The 32x, The Genesis/Megadrive, The SegaCD, the Master System, and the Game Gear.\n\nBy support I don't nessicarily mean games so much as technical and customer support. Also while the Megadrive did INSANELY well in Brazil (to the point it's still being made,) and in Japan the Saturn was hot (we did'nt get a lot of the quirky import titles, but on the other hand Japan had never really let the arcade die, so 2d was still a thing where here stateside we were '3d or GTFO.')\n\nAs you can understand this costs a *LOT* of money to keep going.\n\nAdditionally Sega had alienated both retailers and customers with how they mishandled the 32x and the saturn. The SegaCD everyone can forgive, quirky interesting thing that was always advertised as 'just an addon.' The 32x was at first advertised as Sega's next gen, up to and including shells (with or without hardware I don't know but only ones I've seen are empty shells) for a 'Neptune' console which would have been a combination 32x/Genesis all in one.\n\nThe problem is when the 32x was released the Saturn was already out in Japan, and was slated for release for the Christmas shopping rush of 1995. This gave developers and retailers time to gear up and get a solid release date.... except Sega announced during a conference in May where they demo'd the Sega Saturn 'Oh yea, you can buy one RIGHT NOW.' This left the Saturn with a piss poor launch lineup, retailers with their confidence shaken in Sega to the point KB Toys refused to stock their hardware, and on top of all that the Saturn was stupidly difficult to program for because they went and slapped a co-processor in at the last minute.\n\nBy the way the 'extra' time was because Sony was set to release the Playstation roughly around then and the board thought 'well hey let's just go with getting more units in people's hands huh?\n\nThen in 1998 Bernie Stoler, head of Sega of America basically said in an interview 'The Saturn is not our Future.' Granted the Dreamcast was in development but this was a public interview. Consumers and Retailers not to mention Developers saw '*oh shit Sega's jumping platforms again.*'\n\nSega did learn from the Dreamcast's poor Japanese launch and spent most of 1999 hyping the hell out of it. Just hyping and showing demos and gearing up and they came in with all guns blazing. The problem wasn't the dreamcast itself, or even Sony even though several of the PS2 demos were rendered rather than real time. Sega's problem is that they didn't have the money to keep going nor the faith from third party developers to keep mindshare in the face of the playstation 2's launch.\n\nThere were attempts by sega to get Microsoft, who had partnered with them for the dreamcast, to try making the xbox able to play dreamcast games so their customers would have a migration path. While that didn't happen this explains Jet Set Radio Future, Shinmu, and other games getting ports or sequels on the original xbox.",
"Imagine if Sega did succeed with the DC, where would be now? Do you think they would have gone to making just games still, or would we have some awesome Sega console today?",
"There's a lot of misunderstanding that the Dreamcast was the reason for Sega pulling out of the console market, but it was actually selling okay when it was cancelled. Not great, but it was on track to outsell the Gamecube over it's lifetime. The real issue was the loss of consumer trust after the Sega CD and 32x. These were expansions for the Sega Genesis which were unsupported due to low sales and released back to back. This was then followed by the Sega Saturn. That is 3 hardware pieces released in a few years, back to back. People were wary of Sega because it seemed to just drop support at the first sign of trouble. So no one in the largest market for Sega (North America) wanted to risk buying the Saturn because they were worried that the company would do the same thing to the Saturn as they did to the last two hardware pieces. This was on top of the fact that the Saturn had very few games, no killer app, and a lot of the bigger games for the Saturn only came out in Japan.\n\nBy the time the Dreamcast came out, Sega was already financially crippled by the last 3 hardware pieces. New management took over Sega part way through the strategy of the Dreamcast and that new Management decided the console market was too volatile and canned support about two and a half years into the system. This new management also did things like cancelling sequels to well known Sega franchises, such as a 3D Streets of Rage 4 that was in development based on it's genre alone without knowing the popularity of Streets of Rage. So what it really came down to was not the Dreamcast, but everything between the Sega Genesis and it's eventual release. Had Sega not released the 32x or Sega CD, it's possible they could have kept consumer trust when moving on to the Saturn and Dreamcast. On another short note, this is why Nintendo decided to stick with the Wii U as long as it has despite the sales it currently has. They wanted to avoid Sega-ing themselves out of the console market.",
"After the dreamcast Sega decided it would make more money and do better if it was a software developer only. Basically did it because their really wanst any room for them in the market anymore. That being said Id love for them to team up with old time rival Nintendo to make a kick ass console. "
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[
"http://www.amazon.com/Console-Wars-Nintendo-Defined-Generation/dp/0062276700/ref=sr_1_1?ie=UTF8&qid=1450145280&sr=8-1&keywords=the+console+wars"
],
[],
[],
[
"https://www.youtube.com/watch?v=PMAg46zaRbs"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://www.youtube.com/watch?v=6xdBVHSrdzg"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
4vd7su
|
Why do some metals turn bright red and white when they are melting? Why don't they just turn to liquid like mercury does?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4vd7su/why_do_some_metals_turn_bright_red_and_white_when/
|
{
"a_id": [
"d5xrnmx",
"d5xs1j6",
"d5y5rir"
],
"score": [
12,
4,
3
],
"text": [
"Because the melting points of most metals are much higher than Mercury and at high temperatures, the thermal radiations all objects gives off (including you, your dog and your chair) shifts into the visible spectrum.\n\nThis is called the [Draper point](_URL_0_). It happens at 525 Celsius.",
"It's [blackbody radiation](_URL_0_). Everything glows when heated. Murcury \"just\" turns into a liquid because it melts when it's too cool to glow. If you heat it to the temperature you heat metal to make it glow red, it will glow red.",
"Blackbody radiation. *Everything* glows, just most of it at 'colors' that we can't see (infrared). If something gets hot enough, it glows red. Hotter still, white. Liquid or solid depends on how much energy a particular molecule can handle. "
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Draper_point"
],
[
"https://en.wikipedia.org/wiki/Black-body_radiation"
],
[]
] |
||
cn6xjl
|
How do Colloids work?
|
I understand that they are molecules that are used in mixtures to create a sort of “gelling” but is it because how they are arranged or due to specific bonds? How does its presence actually cause particles from not being able to settle?
|
askscience
|
https://www.reddit.com/r/askscience/comments/cn6xjl/how_do_colloids_work/
|
{
"a_id": [
"ewcu8xx"
],
"score": [
4
],
"text": [
"Colloids aren’t a molecule or additive, they’re a state of a mixture. Specifically, a colloid is formed when the particles (not atomic particles, particulate/macroscopic particles) are too small to settle out. The particles are so small that gravity doesn’t affect them nearly as much as other forces, like boyancy, eddy currents, or molecular interactions. So these forces determine where any individual particle goes, rather than gravity. \n\nThink of it like dust in the air, the dust is so light any little breeze can set it floating. But since liquids are so much more viscous than air the dust literally can’t fall because the force of gravity can’t pull it down strong enough to move the liquid out of the way. And also, the boyant force isn’t strong enough to send it to the surface, so it just hangs there, totally dependant on the currents of the liquid."
]
}
|
[] |
[] |
[
[]
] |
|
2q3hq2
|
why should someone never refreeze something that has been unfrozen ?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2q3hq2/eli5_why_should_someone_never_refreeze_something/
|
{
"a_id": [
"cn2gkei",
"cn2gnyx"
],
"score": [
2,
2
],
"text": [
"Generally when frozen foods are frozen for sale/storage they are done so in a way that prevents large ice crystals from forming and damaging the food. You can't easily do this at home.\n\nThis was the big advantage that Birds Eye had when it first started - its founder, Clarence Birdseye, realized that fish frozen by the Inuit in Newfoundland was much better than fish frozen in New York and he reasoned that the difference was the speed at which they were frozen. Turns out, if you freeze something faster the ice crystals don't get as big and mess with the food as much.\n\nWhen you unfreeze and re-freeze something you freeze it slowly since you probably don't have an industrial freezing machine and that causes larger ice crystals to form in the food, which makes it taste worse. The rule isn't really \"don't unfreeze and refreeze,\" but rather \"don't freeze for preservation without the proper machinery/techniques.\"",
"When you freeze things, all the water in it crystallizes. Those crystals can rupture cell walls, destroying the texture of the food.\n\nIn commercial environments, they use blast freezers to chill the food really fast, giving you very tiny crystals. Tiny crystals are less likely to damage your food. Home freezers are much warmer & result in much larger crystals which are likely to puncture cell walls, leaving you with nasty, limp broccoli.\n\n"
]
}
|
[] |
[] |
[
[],
[]
] |
||
2k9icr
|
the ending of the sopranos
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2k9icr/eli5_the_ending_of_the_sopranos/
|
{
"a_id": [
"clj70s9"
],
"score": [
4
],
"text": [
"Here's a very detailed analysis:\n\n_URL_0_\n\nI personally think you have to pick one of two narratives:\n\n1. Tony was killed by the man in the members only jacket, with the ending tied to prior episodes where the characters discuss the fact that you you never see death coming. The fade to black is Tony's point of view as he dies.\n\nor\n\n2. Tony lives, and the audience is just on edge experiencing what it will be like for Tony for the rest of his life -- always worrying about death and his assassination from an unnoticed attacker.\n"
]
}
|
[] |
[] |
[
[
"http://masterofsopranos.wordpress.com/the-sopranos-definitive-explanation-of-the-end/"
]
] |
||
3fpcdl
|
why do some sites not allow you to have special characters in your password? wouldn't it be better to always have as secure a password as possible?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3fpcdl/eli5_why_do_some_sites_not_allow_you_to_have/
|
{
"a_id": [
"ctqpo54",
"ctqv79z"
],
"score": [
10,
2
],
"text": [
"There have been news stories about websites getting hacked, and the hackers making off with lots of customer/employee/third-party information. How do hackers normally do this?\n\nIn the younger days of the internet, most sites were vulnerable to an exploit called SQL injection. SQL is a programming language associated with a type of database. A database is what actually stores information that website visitors put into the website so they can use the site how they want. Most sites these days have a database they rely on to control--among other things--how users can access the site's services. Other sites use flat files or databases stored in flat files, such as those created and managed by Microsoft Access, which come with their own problems, but we'll stick with actual databases here. \n\nFor example, whenever you sign up to use the services of a website, the information you put into the account setup page is then stored in a database. You are actually telling the web application what information to put into the database by inputting values into the page's input fields, then clicking the \"Submit\" button. The page will ask you for things such as a username and password, maybe your name and birthdate, and whatever else the web site needs to build a profile of you. Depending on the site, it may even ask a user for their credit card details and other financial information. The web application updates the database by using an application account to log into the database, then either inserting new information into the database, or updating the information already in the database so it can be used later. When you then log into the website later, you input your username and password you set up when you created your account, and the application attempts to retrieve the information from the database, checking to see if what you put in is the same as what is in the database, then it gives you access to the services available to your account.\n\nWhere it will sometimes go wrong is when the web application is told to get data from the database that the application is not supposed to return to a normal user. This is accomplished by knowing what the application expects the user to put into a certain input field, knowing how the application's queries to the database are written, and knowing that either the application administrator or the database administrator did not limit the web application's access to the database--giving the application access to everything in the database, instead of limiting the application for just the tables and permissions it needs.\n\nHere is a simplistic example. A user wants to log into a web site. The user puts in the username and password for his or her account. The web application usually then logs into the database and performs a query--SELECT \\* FROM users where username=user1 and password=password2. If a valid row is returned, the user gets logged into the site, is given the permissions the account is set up with, and continues the session. If no data is returned, the user is deposited on the \"Wrong password\" page. Seems logical, right?\n\nNow, say a hacker logs into the same website, but he or she does not put in a valid username--the hacker simply puts in an asterisk in the username and password fields. Depending on how the application is written, it may log into the database and perform this query instead--SELECT \\* FROM users where username=\\* and password=\\* (reddit may have a formatting problem with that). Depending on how the application and database are set up, the hacker may get a database error, he or she may get logged into the first account set up in the web site (which often is the admin account), or the application may return a list of user accounts, complete with usernames and passwords (and maybe credit card numbers, expiration dates, etc). You can see how this may be a problem. There are other methods of tricking the application into giving up data, using a similar method of SQL injection, but the result is often the same--either someone has acquired more information than they need, or someone is just given the keys to the kingdom.\n\nTo combat this problem, some websites have written the database queries their applications use to get data from the database so that queries do not return so much data, which in some cases results in a tiny performance boost. For example, a SELECT userid FROM users where username=\\* and password=* may simply return a list of userids instead of the entire users table--but some applications will allow the hacker to be logged into the first account in the database--the admin account, usually. Also, most sites do not save account passwords to their databases in readable form--they run the passwords through an encryption algorithm before saving them as hashes in the database--instead of \"password2\", there may be a long string of random characters and numbers in its place. So, a user logs into the database with \"password2\", the application immediately puts the user's input through the encryption, and if it matches the resulting hash in the database, the user is allowed access to the account. However, in poorly-written applications, this still results in an unauthorized user logged into someone else's account. In an effort to stop this, most sites today use code which scrubs most special characters out of input fields to guard against sql injection. So, when a hacker goes to put asterisks in an input field, the hacker presses Submit, the application immediately scrubs the asterisks out, and the hacker is left with either a database error, or--on well-written applications--deposited on a Wrong Password page. This is normally called \"sanitizing\" the input. Most of the sites you will browse have this feature in the application, but some sites will not. Best to not try and find out.\n\nSo, basically, you're not allowed to have special characters in the password field on some sites because the website owners don't want other people getting access to your information, so they run most of their inputs through a scrubber that stops what used to be a very prolific exploit.",
"Lazyness. Sanitizing inputs takes time, effort and knowledge. So some developers take the easy (and less secure) way out."
]
}
|
[] |
[] |
[
[],
[]
] |
||
105pfj
|
What sort of judicial system did the Confederacy have during the Civil War?
|
Law student here- by the time 1861 rolled around, U.S. Supreme Court precedent had already handled some extremely fundamental questions about the judiciary, from issues concerning federalism/separation of powers to appellate/original jurisdiction. I realized, however, that I am entirely unfamiliar with the judicial structure established by the Confederacy and how that structure drew on the U.S. court system (as it existed at the time).
For example- did the Confederacy have a trial/appellate/supreme court structure? Were there two jurisdictional systems (state and federal)? Was there a notion of judicial supremacy (meaning, did they have a Marbury v. Madison equivalent)? And, drawing back on what I mentioned earlier, how did their judicial system deal with the fundamental issues SCOTUS had dealt with (for example, questions of original jurisdiction or habeas corpus)? Could you, for example, theoretically use SCOTUS precedent when bringing a case in the Confederacy?
I haven't seen much written on the topic so I was wondering if anyone here might have some idea.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/105pfj/what_sort_of_judicial_system_did_the_confederacy/
|
{
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"Someone did a presentation about this in the constitutional law class I took ages ago but I barely remember it. I do remember that at a national level, the [Confederate Constitution took the Article III language virtually word-for-word](_URL_0_) from the United States Constitution. It empowered the creation of a supreme court and tribunals inferior to it, but Davis and the Confederate Congress never got around to appointing justices to a Supreme Court of the Confederacy. I believe most of the district court judges simply continued serving in the antebellum benches. Given that early American courts frequently cited British common law precedent from before the Revolution (and the Supreme Court still cites pre-revolutionary British common law to this day), I'd theorize that the Confederate district courts continued to operate under prior precedent unless that precedent was explicitly changed -- but don't cite me on that.\n\nState courts, to my knowledge, functioned the same way they did before secession since the states themselves didn't change. It'd be interesting to see the extent to which the Confederate courts changed after 1865, because Republican state legislatures theoretically could've created a whole new judiciary by ousting the sitting judges on treason charges. That'd be interesting to research too.\n\nIf you do end up researching the Confederate judiciary, please send me your findings! My interest has definitely been piqued."
]
}
|
[] |
[] |
[
[
"http://en.wikisource.org/wiki/Constitution_of_the_Confederate_States_of_America"
]
] |
|
3jhveu
|
stock dividends
|
Title
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3jhveu/eli5_stock_dividends/
|
{
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"If a corporation makes a profit, it may decide that it wants to share some of the corporation's profits with its owners (known as shareholders). The profit that is paid by a corporation to its shareholders is called the dividend. The dividend is issued \"per share\", which means that the corporation might pay $1 per share. In that situation, someone who owns 10 shares of the corporation's stock would receive $10 and someone else who owns 25 shares would get $25. The corporation is free to decide the amount it pays per share.",
"Ok, so to understand dividends, you have to understand the point of a company issuing stock.\n\nA company issues stock in order to exchange shares of ownership of the company for capital they can use to expand. The owners of a private company will issue stock, and sell it to the public in what is called an initial public offering (IPO).\n\nUsually, the IPO is the main time that a company can actually turn shares of ownership into cash money. Most companies and the original owners of the private company will retain at least some shares for themselves that they have the option to sell later, but they usually don't sell since this is also equivalent to giving up some control of the company.\n\nThis is because owning a share of stock also gives you some rights in regards to the company. For one, the company's financial reports are required to be made available to share holders.\n\nAlso, important decisions about the company can sometimes be left to a vote among share holders. For example, the membership of the board of directors is usually nominally controlled by a vote, and if enough share holders are upset with a given board member, they can kick them out.\n\nThat's a long explanation to make the point that owning a share of stock makes you a partial owner of the company. As a part owner, you are entitled to some of the proceeds of the company, should there be any. This is the important bit that explains dividends.\n\nUsually, a company doesn't make any money while it still has room to expand. Every bit of money that comes in and isn't earmarked for something else, gets rolled back into hiring new people, buying new equipment, and producing more of whatever the company does.\n\nBut, the theoretical expectation is that once a company gets big enough, it will run out of ways to productively expand, and more or less stop growing. When a company reaches maturity like this, it will start issuing dividends out of its cash reserves. These are the disbursements of the money that share holders have purchased the rights to.\n\nNow, normally, many companies aren't anywhere near that level of maturity. But in theory the possibility that any given company will eventually start paying dividends is what drives the stock price on the open market. If a company is doing well, it's more likely to eventually issue dividends, and the price per share should go up. If it's doing poorly, then it may fail before it starts paying dividends and the price should go down.\n\nWe tend to lose sight of this, since most people make money from the stock market by buying stock low, and selling high, without ever receiving dividends at all, but the whole system makes a lot more sense when you realize that stock value is driven by potential future dividends and not some sort of inexplicable self sustaining cycle."
]
}
|
[] |
[] |
[
[],
[]
] |
|
d4oqx2
|
what determines whether a pro sports team is named after a city (dallas cowboys), or after a state (minnesota vikings)?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/d4oqx2/eli5_what_determines_whether_a_pro_sports_team_is/
|
{
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"It is down to the owner plus any special tax break the local community has given them which may also involve promoting the city or state. In addition existing teams in the state may restrict the naming process.",
"That’s completely up to the team owner(s), they can name it whatever they like. \n\nLook at the Angels in baseball, for example. Over they years, they’ve been the California Angels, Anaheim Angels, Los Angeles Angels, and now the Los Angeles Angels of Anaheim."
]
}
|
[] |
[] |
[
[],
[]
] |
|
1cmgip
|
If I travel fast enough to red or blue shift radio waves, what would happen to the sound coming from a radio program?
|
I realize that I would have to adjust my station to the new frequencies, but would the radio beat or tone shift up or down as well?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1cmgip/if_i_travel_fast_enough_to_red_or_blue_shift/
|
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"Well, it would change the station first of all... So if you tuned in at 98.5 MHz you might instead tune in at 98.6 MHz. \n\nAfter that I think things should be slowed down, regardless of if it is [AM](_URL_0_) or [FM](_URL_1_). If we had a 10% elongation of the wave, we should also have a 10% slow down in modulation of the wave, so a 100Hz tone lasting for a second would instead be ~90Hz lasting for 1.1 seconds. ",
"If it is apmlitude modulation then obviously if you compensate for the shift of the carrier wave (by tuning to the shifted frequency) and not compensate the shift of the carried wave you will hear a shifted recording. \nIt is easy to imagine visually - stretch/compress the compound wave, demodulate (filter the carrier) and you are left with stretched/compressed recording. \nSame applies for frequency modulation.\n\nAlthough, if phase shift keying is employed, this should not be impacted since the phase shift would remain the same even if the carrier wave gets shifted.\n",
"In the case of AM, the entire wave is based on the amplitude of the carrier which is not changed during doppler shifting. The entire signal appears compressed (or expanded) due to the shifting, so the modulating signal should also appear compressed or expanded by the same ratio. So you'd hear a proportional shift in tone.\n\nI don't posses the math-fu to try to work out how the spectrum of FM radio would change. I tried staring at _URL_0_ but I don't have nearly enough familiarity with fourier transforms to give you an answer that I'd be confident about. ~~My rather simple reasoning would have me believe that the signal would get louder during a blue shift and softer during a redshift....~~ Edit: D'oh of course it would have to do the same thing. You can't have a signal come in faster than it's being transmitted from the source.",
"In both cases you would hear the signal speed up or slow down, and in both cases you would have to adjust your tuner up or down. Both the modulating (high frequency) and modulated (voice or music) signals are functions of linear-time (in opposition to time squared or the log of time), so if a 500THz red light gets shifted down to 400THz, your radio station at 100MHz will be shifted down to 80MHz, and the 1KHz test tone will shift down to 800Hz.\n\nModulation is cool because the modulated signal is still present in its original form. In the case of AM, you can pick it out by connecting the peaks or valleys of the modulated wave. In FM, you can pick it out by shifting the spectrum around -- which is incidentally exactly what happens when you have red or blue shift!\n\nYou could almost say that traveling at a certain rate is the same thing as single-sideband FM modulation!"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/AM_broadcasting#Operation",
"http://en.wikipedia.org/wiki/FM_broadcasting#Modulation_characteristics"
],
[],
[
"http://en.wikipedia.org/wiki/Frequency_modulation"
],
[]
] |
|
bzohlr
|
What makes an explosive effective at different jobs?
|
What would make a given amount of an explosive effective at say, demolishing a building, vs antipersonnel, vs armor penetration, vs launching an object?
I know that explosive velocity is a consideration, but I do not fully understand what impact it has.
|
askscience
|
https://www.reddit.com/r/askscience/comments/bzohlr/what_makes_an_explosive_effective_at_different/
|
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"Armor penetration effectiveness is usually achieved by concentrating the blast into a small area by what's known as a [shaped charge](_URL_0_). \n\nOther common explosives are [gun powder/black powder and flash powder](_URL_1_) (common in the fireworks industry). The big difference is the speed at which they burn. You have to confine gun powder into a small area in order for it to be effective (such as bullets), and even then it's still a relatively small explosion. Flash powder on the other hand is known as a high explosive because it converts to a gas incredibly fast. It's the difference between a loud pop of gun powder and the fragmenting explosive that flash powder creates.\n\nHopefully someone else could provide more in depth explanations for the \"why\".",
"Armor penetration and launching have been covered in the previous post. With “anti-personnel” charges it’s a little different. With explosions that cause damage to people, it’s usually not the explosion itself, but the shrapnel from said explosion that causes the damage.",
"When it comes to demolishing buildings, it's not really down to the type of explosive used. You can use any high explosive for the job. The challenge/skill with demolition is figuring out which parts of the building are actually holding it up (load bearing). Then putting enough of your explosive to destroy those parts, and destroy them in a way that causes the building to collapse inward on itself instead of falling to the side which would damage stuff around it.",
"Something not mentioned yet is that different explosives have differing degrees of 'brisance'. Think of it as the 'shattering capability' - one explosion might 'push' an object away at high speed, where another might shatter it into tiny fragments but not necessarily propel those fragments as fast.\n\nC4 has extremely high brisance for antipersonnel and anti-armour, and gunpowder has low brisance for launching objects.",
"Application of force is the really simple answer. Explosives in construction are designed to \"break-up\" or loosen material, so that it can be removed with an excavator. Building demolitions are incredibly precise operations, but the same concept is being used. They're just very carefully applying explosive force to the right columns and beams to bring the structure down safely so that the parts can be scooped up and hauled off. In this case they apply force in a sort of \"all around me\" form, a pressure bubble that can fracture concrete and compacted earth.\n\n & #x200B;\n\nArmor piercing is usually never done by the actual explosive. An RPG uses a conical sheet of copper and a shaped charged to force a liquid jet of copper through armor plates. This copper is so hot that it will instantly cook anyone inside the sealed compartment of the vehicle by heating the air. From what I've seen most AP munitions follow a similar principal. On tanks for instance, their armor piercing Sabot rounds are really just a casing for a huge metal rod (I think tungsten? Maybe depleted uranium?) that just YEETs and applies a bunch of force into the armor in an attempt to poke a hole in it. Sabot rounds actually don't use any explosives beyond the charge used to fire it and shed the casing. The kinetic energy involved in these sorts of munitions is so great that most humans would suffer fatal injuries just from the shrapnel produced on the other end of the round. The important point for both these types of AP munitions is that the force is applied in a very small area, like the diameter of a quarter or something, and is supported by incredibly high kinetic energy and heat. \n\n & #x200B;\n\nThis is why angular and sloped armor is so effective at preventing armor piercing munitions. A slope would redirect a lot of the energy of your tungsten rod, or cause an RPG to glance and lose a lot of the effectiveness of it's copper jet.",
"Quarry/Mine Blaster here.\nSome explosives have a very high velocity and but lower gas content. They have a \"high brisance\" which cracks material but doesn't throw it. Think of it as a very fast slap.\n\nOther explosives have a lower velocity but create a very large amount of gas very quickly. They don't shatter the material as much but they throw and heave it further which also aids in breaking the material. Think of this as a large shove instead of a fast slap.",
"Building demolitions are done by staggering out the explosions to build a bigger shockwave with fewer explosives. The idea is to time the second explosive so that it detonates at the same moment that the shockwave from the first explosive reaches it. Then the third is timed to coincide with the arrival of this new, larger shockwave. \n\nOn top of that you have far more control about where and how the building collapses with a series of charges than with a single big boom. You can collapse a building inward to minimize the total footprint, or you can collapse it to the side, away from other structures. \n\nWhen done properly, explosive demolitions reduce the total work enormously and give you a lot of control on how the structure comes down. When done wrong you may end up with a partial collapse or no collapse, which can very dangerous and unpredictable.",
"keep in mind that various utility aside, the most desired property of any explosive is that it doesnt explode until you want it to. There are many more powerful explosives than TNT and C4 but the reason those are popular with construction and military crews are because they are stable in regular conditions and dont blow up the workers on the way to the job.",
"Explosion creates force, it all depends on how you utilize it. \n\nFor example, High Explosive Anti Tank type weapons such as RPGs focus the explosion into a single point, creating a very hot jet used for penetration. \n\nFor heavy armour, the Brits came up with HESH (High Explosive Squash Head), in which the tank round would hit the armour, the explosive would flatten out against it and then it would detonate, causing the shockwave to travel through the armour and make the inner face shatter, internally sending bits of metal flying within a tank. \n\nThe Americans used thin metal on their High Explosive shells and lots of explosive filler, thought process being you kill a guy with the actual explosion. This was very useful for destroying buildings and other material as it was simply a large amount of force.\n\nFor anti infantry, the Soviets used High Explosive Fragmentation. Basically a giant grenade, the shell had a moderate lining designed to cause maximum shrapnell when detonated, meaning it would be able to deal damage beyond the shockwave radius by expelling shrapnel",
"For the most part the explosives are the same. The means of delivery is what changes. Building = detcord and shape charges. Anti personal = shrapnel. Anti vehicle = shape charge with metal cone. This is not 100% but you get the point. Source....many many years ago I was with Army bomb unit.",
"For destructive purposes the main considerations is amount, placement, and, in some cases, the shape of the explosives. The explosives can be shaped as a Chevron to concentrate the force to limit collateral damage and decrease the amount of explosives needed.",
"The brisance of an explosive, a measure of it's explosive pressure, would give you an idea of power, in a general sense. However, as others have pointed out, an explosive is oftentimes used as a tool in conjunction with other tools or techniques to achieve a more specific purpose.\n\nFor example, an explosive charge on the back of a copper plate results in the copper plate liquefying and being blown outwards. If this is shaped over a railroad rail, you can effectively cut through it like butter. Another example is using an explosive to compress a magnetic field, which can result in a MASSIVE output of millions of amps (explosively-pumped flux compressors, used for generating huge EMPs).",
"Detonation velocity is heavily used as a metric because it is very easy to measure, and reasonably correlates to other performance metrics. A lot of these correlations were established fairly early in the history of explosives engineering and have stuck around because they work.\n\n & #x200B;\n\nIn an ideal world, if you want to achieve destructive effect, you use the most powerful explosive available to you, in reality you are cost/sensitivity/packaging limited. So you get what you can.\n\n & #x200B;\n\nFor blast applications: total energetic output per gram of HE seems to dominate (and why metallized explosives are dominant in the most modern applications).\n\n & #x200B;\n\nFor demolitions: really any explosive will do, its where you put it that matters and how efficiency you use the bulk you have.\n\n & #x200B;\n\nArmor pen, you use shaped charges, which requires a high VOD and a high Gurney velocity.\n\n & #x200B;\n\nExplosive acceleration of objects that can survive it (ie chunks of metal), require a high Gurney velocity (actually you need a thermodynamically high PV isentrope), and this parameter correlates with detonation velocity.\n\n & #x200B;\n\nA lot of the comments in this thread are absolute junk, as an FYI.",
"Several factors.\n\nDetonation velocity, explosion shape, shrapnel, placement, and confinement.\n\nI'll go through each of your particular questions one by one.\n\nSo there are 2 ways of thinking about building destruction. Demolition, and destruction.\n\nFor demolition, it's all about placement. Holes are drilled in critical support columns and explosives are inserted directly into the holes. The size of these explosives is usually relatively small, but they're highly contained and will cause critical damage to the support.\n\nFor destruction, explosion velocity is critical. We're talking a bomb that's just planted somewhere to do damage. Typically you want a slower more \"rumbling\" explosion that will be more likely to damage stone and concrete. ANFO is really good for this, and is why it causes such utter devastation when it goes off.\n\nAnti-personnel is typically achieved by shrapnel. Essentially you want to shoot a gun in every direction at once with as many little pieces moving as fast as possible. So you want a high velocity explosion with a breakable shell around it that will go in every direction upon detonation. This is exactly why the classic \"pineapple\" grenade has those bumps on it. They're weak points that break apart.\n\nArmor penetration is all about the shape of the explosion and what it's propelling. Most armor penetrating explosives have what's known as a shaped charge. This is a cone shaped high velocity explosive that is covered by a metal (usually copper due to its high heat conductivity). When it detonates, it fires a spear of superheated copper into whatever it's pointed at. Usually piercing armor and raising the inside of whatever it hit to several tens of thousands of degrees for a short period of time.\n\nLaunching a projectile is all about confinement. Basically you don't want gas escaping around the projectile. And you want all of that energy to be transferred to the projectile. However, you can't have **too** large of a charge as that may damage or burst the barrel. Longer barrels typically allow the gas to expand behind the projectile for a longer period of time which will usually result in higher muzzle velocity. Although there's a limit to this. Longer barrel doesn't always mean faster or more accurate bullet."
]
}
|
[] |
[] |
[
[
"https://en.m.wikipedia.org/wiki/Shaped_charge",
"http://www.unitednuclear.com/bp.htm"
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|
1q7zq8
|
why do wombat's poop cubes?
|
Title says it all, I just can't wrap my head around the fact that they poop little dice shaped turds.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1q7zq8/eli5_why_do_wombats_poop_cubes/
|
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"Wombats poop on top of rocks and logs near their burrows. The reason for this is not to keep intruders away, but to use as an indicator to know where their home is. Wombats have terrible eyesight however they have an extraordinary sense of smell. The reason for these rubiks poop is because if the Wombat's are to effectively effectively smell their way home, their turds must remain where they dropped it, hence the fact that their excretion is cube, not circular. Who want's their shit rolling away?"
]
}
|
[] |
[] |
[
[]
] |
|
2zq7a7
|
how does the army/military wash clothes while deployed?
|
How does the army/military wash clothes and laundry while deployed? I'm assuming they just hand wash everything? Wouldn't everyone smell like ass? Hoping someone could chime in. Just a random thought that I couldn't find anything on google.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2zq7a7/eli5_how_does_the_armymilitary_wash_clothes_while/
|
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"Modern armies generally deploy with enough support machinery to wash clothing, and hand washing is quite effective.\n\nHowever everyone smells like ass anyway. Welcome to the Army.",
"At the laundry. Deployed at base you still sleep in a bed/cot. Deployed in the field, you don't wash",
"Depends. If they are at let's say camp leather neck they just drop it of and pick it up the next day. When I was deployed I was at a fob without running water so we used 5 gallon buckets and scrub brushes. and hung them out to dry. Which was the worst since sandstorms would come out of nowhere and make your wet clothes muddy",
"They do have laundry areas, with machines and detergent and everything.\n\nIf you have a base with 1500 people working 12+ hours a day on it, there are some \"creature comforts\" that are going to be there. They are going to have laundry machines, they are going to have kitchens, they are going to have a recreational area, they are going to have electricity and relatively running water and some buildings with fans/air conditioning.\n\nIf you have a bunch of trained people used to first world amenities, then stick them in a place without them, the best way to get them to work efficiently and not gripe is to give them a few comforts from home.",
"You turn them into 3rd party nationals and pick them up 3 days later, folded and clean. It's actually the best part of being deployed.",
"Shower first with your clothes on, wash everything as you would normally shower with clothes off. Then take the fatigues off and wash again. Not ideal, but it worked. This was Royal Army BTW.",
"5 gallon bucket when you're at a FOB without running water.",
"Ex-US Army here. Typically we dropped them off at the \"Cleaners\". The clothes come back smelling like nothing at all, folded, and wrapped in plastic. This took anywhere from 24-72 hours depending on where we were.\n\nIf I wanted something immediately I just took a box of tide to the sink and hand washed it. Never had to go outside of any sort of base but I had a friend that did. He got dysentery his first day out and ended up shitting on himself. He had to wear that for 3 days until they came back. ",
"On the sub we had 2 washers and dryers. For 150 people. Some people don't wash their clothes, but you were given a schedule to do it once a week. ",
"From my experience, there are three situations.\n\n1. You wash it yourself. Depending where you get stationed it, a pretty cherry camp will have a laundry room provided either by the Army, MRW, or locals.\n\n2. Speaking of locals, sometimes there will be a laundry run by the hadjis. Toss a third of your clothes in a bag. Don't put too much, you have to be careful of delays or any other reason you don't get your laundry back and you don't want the same thing for a week or two straight. Even recycling dirty clothes is better than seeing salt stains on your uniforms. Drop the bag off and pick it up a few days later.\n\n3. Army has these... well shit, I don't know what they're called. Part of a quartermaster unit, they drag around water bags and set up showers and laundry services. Just like the hadjis, except not as reliable as far as losing your shit goes (sorry, I had to).\n\n4. And then the warning from method 2: sometimes you just don't. You're at a shitty FOB, you're on a shitty convoy, or god's in a shitty mood. You just recycle dirty clothes and worry you're creating a new bacteria that's going to destroy mankind from the bottom of your laundry bag by hanging it on the laundry outside of your tent.",
"No one has mentioned the Navy. Ships have laundry rooms. Size depends on size of ship and size of crew. I was on a amphibious ship, LSD type. Crew was ~350. IIRC we had 5 washers and 5 dryers. There wasn't a rotation, meaning if it was open you could use it. That's all if you wanted to do your own laundry. There is a ships laundry that the crew isn't allowed to walk into themselves and use. Crew members work down there and do laundry all day. Someone is assigned to clean berthing and take all laundry down and pick it up and bring it back on a regular basis. If you wanted to send your uniform in that laundry, go ahead. But it wasn't recommended on my ship. That laundry was usually used for linen.",
"I got out of the Infantry in 82, reckon things have changed a lot, back then when you were in the field you got nasty and kept getting nastier till you got home. Didn't matter to us, you go full nose blind after awhile. Used to seriously gag out our old ladies when we got back though, you could always tell, you see a couple going down the road with the windows down and the temps 5 below 0, you know she's about to hurl just tryin to get his nasty ass back to the house!",
"Just for the record for he first six months I was in Iraq in 2003 we washed out clothes ourselves. We had one of those old fashioned wash boards and a bucket and hung our shit up to dry on clothes lines made out of 550 cord. Absolute worst part of the deployment for me (except getting shot at... Maybe). "
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
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|
7m2k57
|
in movie scenes depicting large crowds or groups, do the extras usually have scripted dialogue or do they ad-lib?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7m2k57/eli5_in_movie_scenes_depicting_large_crowds_or/
|
{
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"text": [
"They aren't talking at all. They are just pretending to talk. The sound is added in later. If they really talked it would interfere with the main actors dialogue recording. Sometimes directors will give them some motivation (like ask one couple in the background to pretend to argue or something). Even if they are working or doing something they are asked to do it completely silently. \n\nSource: I work in the film industry. "
]
}
|
[] |
[] |
[
[]
] |
||
rmxpp
|
Do animals get tired of eating the same food day after day?
|
Domesticated animals especially. I know I get tired of eating the same sandwich three days in a row. Are there any studies out there about animals and food preference?
|
askscience
|
http://www.reddit.com/r/askscience/comments/rmxpp/do_animals_get_tired_of_eating_the_same_food_day/
|
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"Modern humans actually a require a great multitude of different vitamins, minerals, and nutrients in order to survive. A lion can eat meat all day everyday and never get scurvy. For humans however, it makes sense from an evolutionary standpoint being as we have such a long list of required nutrients, that we would evolve to crave variety in food. \n\nI'm not a scientist but off the top of my head I can think of quite a handful of dire reprecussions associated with vitamin/mineral deficiency such as: Vitamin C deficiency(scurvy), Vitamin b12 deficiency(anemia), calcium deficiency(osteoporosis), protein deficiency(too many to list, ask any vegetarian that doesn't understand nutrition what this is like), and so on. If you eat fruit exclusively you'll lack protein, if you eat meat exclusively you'll lack fiber and vitamins, etc.\n\n",
"To clear this up a little bit: The dry food we feed our pets contains a good amount of [varied nutrients, minerals and vitamins](_URL_0_) that animals need.\n\nIf the world were to go under and survival were the main priority, you'd be better off salvaging dried cat and dog foods then almost anything else.",
"Another point to be considered is the number of taste buds the animal has. The dog for example, has about 1/6 the amount of tastebuds that a human has. Another interesting example is the chicken which has somewhere around 16 tastebuds. ",
"A 2006 paper titled \"Brain mechanisms underlying flavour and appetite\" by Edmund Rolls in the Philosophical Transactions of the Royal Society shows that non-human animals (in this case, macaques) definitely experience sensory satiation. I can post some of my notes on the paper, but I was focused on functional neuroanatomy at the time rather than the topic at hand. ",
"I know that certain animals such as land hermit crabs preferentially choose foods that they have not eaten recently([source](_URL_0_)). This seems to be an adaptation to both help ensure that the crab gets all the nutrients it can, and to avoid eating bad food too often (I would imagine this is a trait that may be found in other scavenging \"custodial\" species of animals).",
"Animals are able to detect deficiency in indispensable amino acids and adjust which foods they eat accordingly.\n\nHao, S. et al. Uncharged tRNA and sensing of amino acid deficiency in mammalian piriform cortex. Science 307, 1776–1778 (2005)\n\n_URL_0_",
"there is an episode of [radiolab](_URL_0_) that explores zoos and there is a story about what animasl are fed in zoos and what has changed over the last 20 years considering what animals like/dont like to eat. i would recommend giving it a listen its a great episode.",
"I did my doctorate in neuronal control of appetite/obesity. We would put mice on a high fat diet (bright pink, made up of a ~60% fat, some carbs+protein) instead of their normal 'chow' (like dry biscuits, mostly carbs and protein). The mice would go mental, they loved having a new food. Wait a few weeks, switch back, same deal.",
"Dogs like what food other dogs like. \n\nThey're suckers for peer pressure. \n\nOr maybe it's just common sense, if one dog likes this food, then other dogs know it is safe to eat. \n\n*Source: Dogs acquire food preferences from interacting with recently fed conspecifics.*\n\nSocial transmission of food preferences has been documented in many species including humans, rodents, and birds. In the current experiment, 12 pairs of domestic dogs (Canis familiaris) were utilized. Within each pair, one dog (the demonstrator) was fed dry dog food flavored with either basil or thyme. The second dog (the observer) interacted with one demonstrator for 10 min before being given an equal amount of both flavored foods. Observers exhibited a significant preference for the flavored diet consumed by their demonstrators, indicating that dogs, like rats, prefer foods smelled on a conspecific's breath.\n\n[PMID: 17049752](_URL_0_)\n\n",
"Alright, here's a few points to answer your question and add a little onto it (I work in the pet food industry):\n\nYes, they do get tired of the same food. That's where table scraps come in handy- although they spoil the pet, it adds a little bit of variety and interest into what they're eating. If you don't want to do that, canned food is the best way to go; just add a scoop on top every day of something different.\n\nThat being said: it's necessary to give animals different proteins so their bodies can create the different immune responses to those proteins. It gives them energy, and in puppies and kittens, helps with maintaining their general health later in life. It's a fallacy that dogs and cats should have the same food for their whole life. (It's also a fallacy that kibble helps their teeth, but I digress.) We recommend people change up proteins every bag, if possible. The more frequent, the better.\n\nAnswering a few posts below: my store only sells human-grade pet food. Many of the dog food companies owned by larger human food companies, such as Mars' Pedigree and Royal Canin, use the scraps that are indigestible to humans and puts them into their dog food lines. (personally, we avoid anything like that; anything in our store is going to be human grade and, heck, looks better than half the stuff I eat.) Avoid essentially everything you see on TV, and especially Science/Prescription Diet.\n\nI have many many points that I'd love to get out there but it's too late and I'm tired. If anyone has any specific questions, feel free to ask. If mods need proof of some sort, PM me.",
"Dogs are much more likely to get tired of their food if you give them a lot of table scraps, things like pieces of fat or skin or bone are like candy to dogs, and you can spoil their taste for their normal kibble if you give in to the puppy dog eyes too often. I actually have this problem with my dog, for a good month or so he would refuse to eat his kibble unless we added things like dry sausage or turkey slices."
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Cat_food#Nutrient_chart"
],
[],
[],
[
"http://www.ncbi.nlm.nih.gov/pubmed/9480714"
],
[
"http://www.sciencemag.org/content/307/5716/1776"
],
[
"http://www.radiolab.org/2007/jun/04/"
],
[],
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"http://www.ncbi.nlm.nih.gov/pubmed/17049752"
],
[],
[]
] |
|
382www
|
why has the euro held its value for so many years, then all of the sudden dropped to almost the same value as the usd?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/382www/eli5_why_has_the_euro_held_its_value_for_so_many/
|
{
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"US Fed has slowed down how much money they are putting into circulation (went interest rates are slowly going up.)\n\nGreece and partially Spain have forced the EU to begin their own QE",
"I don't care how anyone ELI5 this question but please do it using an analogy with candy or something. ",
"The comments about Quantitative Easing (QE) are somewhat correct. The central bank of Europe is a authority that regulates the Euro, while the U.S has the Fed to regulate the dollar. One key difference with the Euro however is that countries in Europe are just that; still separate countries. This means that their economic policy needs are varied. Greece could use a massive devaluation in the Euro, while Germany is doing just fine where it is. Trying to operate under a common currency takes all control away from the central banks of these countries, and they must accept what the European Central Bank does. So Greece would like to see the Euro drop (their goods become cheaper to the rest of the world, comparing relative exchange rates.) This increases tourism, exports, etc. The result is a boost in Greece's economy that they need. Therefore the ECB saw it necessary to provide this relief to the countries struggling in the EU, meanwhile the U.S has started to raise interest rates."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
spssr
|
the modern "war on women"
|
I really have this HUGE premonition that this whole thing is a bunch of crap, but I'd like to know more. What makes people think this is actually going on?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/spssr/eli5_the_modern_war_on_women/
|
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"Don't have time to respond fully right now, spend 7 minutes watching the video at the bottom. \n\n_URL_0_",
"There are a variety of issues that have come up that seem to relegate women to second class citizens, two of the biggest being birth control and abortion.\n\nThe fact that viagra is covered by insurance, but some are fighting to keep birth control uncovered. Many in the media hinted that women who needed birth control were sluts. \n\nThe bill that would require women to undergo an invasive vaginal ultrasound (which many likened to being raped) before an abortion. The idea being that they would change their mind after seeing their unborn baby.\n\nIn addition, tax breaks for women who stay home and have children lead to an environment where women are encouraged to give up careers for children and their husbands. \n\nThere is nothing wrong with women or men staying home or being chaste, but when the government is supporting this, it creates an oppressive environment.\n",
"A couple of recent developments lead women to say this:\n\n* All across the nation Planned Parenthood has been labeled as abortion factories and pure evil by republicans. Efforts are underway to defund them. Supporters on the other hand say that abortions are just a very small (and not publicly funded) part of what PP does (best cancer screenings, pep smears, birth control...)\n\n* The GOP is opposed to extending the Violence Against Women Act which makes it easier for women to get help in domestic violence situations.\n\n* They are against abortions even if the mother's health is in danger. Or if she was raped.\n\n* GOP controlled states want to pass/already passed laws that force women who want to abort to look at the unborn child/see videos of other abortions/watch educational videos.\n\n* Some republicans want to end/or did end equal-pay-laws (which makes it easier for woman to sure if they are being discriminated against). \n\n* House republicans wanted to pass a measure that would only cover abortions if a rape was \"forcible\". Hence precluding for example statuary rape.\n\nThoee are just a couple of points. There are many more. \n\nBut if those things constitute a \"war on women\" surely is a very subjective matter.",
"In this election year, many conservatives, particularly Rick Santorum, have gone the \"tradition values\" route, which include a number of issues that primarily affect women:\n\n* abortion - there have been many pro-life candidates, but Santorum takes it a step further, wanted to ban abortion in the case of rape\n* ultrasound guilt trips - requiring the patient to view an ultrasound, in some cases a penetrative vaginal ultrasound, before getting an abortion\n* birth control - Santorum opposes all forms of birth control, and supports a state's right to restrict or even ban birth control for adult women\n* state at home moms - Ann Romney has been touting her choice to be a stay at home mom, when in fact her wealth make her more of a stay at home nanny-cook-housekeeper supervisor."
]
}
|
[] |
[] |
[
[
"http://www.mediaite.com/tv/rachel-maddow-calls-on-gop-to-appoint-sen-murkowski-war-on-women-spokesperson/"
],
[],
[],
[]
] |
|
3r0dsl
|
if one had an electric motor on a car that turned one wheel and three generators on the other three wheels, with two battery banks (one charging and one being used) could i run this car forever?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3r0dsl/eli5_if_one_had_an_electric_motor_on_a_car_that/
|
{
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"text": [
"Nope! Any question that asks \"could I run such-and-such system forever?\" violates the first and second laws of thermodynamics.\n\nMore specifically, you would not be able to recover electricity at a fast enough rate with the three generators to refill the battery powering the motor on the first wheel. Eventually, it will lose power altogether depending on how efficient your generators and motor are.",
"No.\n\nYou're using energy to pull the car *and* using energy to turn the generating wheels to store again as energy. So that, alone, means your plan can't work. Let's say the car takes 50 watts to move, and each generator wheel needs, oh, 10 watts of power to turn and generate power. That means your motor wheel (*in an ideal universe without thermodynamics...we'll get to that later*) would need to put out 30 watts of power *just to turn the other wheels*. But it also has to drag the car, so the total the motor wheel has to use is 80 watts, but you're just getting 30, so no matter what you have a net loss of 50. Even if the car only took a fraction of a watt to move, it would still be a net loss of power.\n\nBut way more importantly, thermodynamics is a thing. Energy is *never* transferred without loss. The wires don't transfer the electricity from the batteries perfectly, so you lose a little. The motor wheel loses energy to friction against the road. The generator wheels also lose friction to the road. The wires lose energy to the batteries, etc.\n\nIf you just had a motor directly turning a generator, you would *still* lose energy. That's like asking if a crank can turn itself...\n\n*Those numbers are just made up off the top of my head and wildly inaccurate.",
"Nope, because the system is not perfectly efficient. There are losses due to heat, (caused by friction of mechanical parts, and electrical losses in the wiring), noise etc, so that the amount of power generated would always be less than the amount needed to move the car.\n\nWhat you are proposing is perpetual motion and by all known laws of the universe, is impossible. Google **Entropy**--the most powerful thing in the universe."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
7c79ka
|
Why were European states such as Britain, France, Germany and more, able and willing to colonize and conquer places like Africa, the Americas, and more?
|
To start: I am mestizo, descended from central American Mayans and the Spanish conquerers - this is not a question alluding to white or european supremacy. I have always wondered (I played lots of Age of Empires growing up), however, why it was that European nations like france, russia, britain, portugal and more has both the resources (more advanced military/transportation technology) and the motivation to conquer and colonize the rest of the world. Why couldn’t the Zulu, the Aztec, the Mayans, Australian aborigines etc. defend themselves? Why we’re sub-saharan african nations conquering the continent of europe?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/7c79ka/why_were_european_states_such_as_britain_france/
|
{
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"dqfhs27"
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"text": [
"Oh dear. I'll be frank with you: the reason why you haven't received an answer to this question is because the answer would be enormous. You could spend the rest of your life studying how these questions apply to but a single group of people - like the Maya - and never arrive at a definitive conclusion.\n\nI'm a bit occupied at the moment but I want to point you in the direction of [a series of posts I made a while back.](_URL_0_) A redditor asked why people in the United States do not say that native peoples were conquered, another user replied incorrectly, and I offered a brief overview of how Europe responded to the conquest. I think the linked reply will give you a taste of how complex the \"motivation\" question is. \n\nBut the real issue I want to discuss is the \"why couldn't indigenous peoples defend themselves\". Again, I want to point you to [a post](_URL_1_) I made on that thread which contextualizes the topic you are talking about. After you have read that material, why don't we see what questions you have and we can go from there?"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/3drttg/why_does_everyone_say_native_americans_were/ct8am3i/",
"https://www.reddit.com/r/AskHistorians/comments/3drttg/why_does_everyone_say_native_americans_were/ctch56l/"
]
] |
|
1q3tuy
|
What was life like in Spain in the early 70's?
|
What was life like in Spain towards the end of Franco's rule? For somebody living in Madrid, what were the big political issues of the time? Was the standard of living decent, and was it rising or on a decline?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1q3tuy/what_was_life_like_in_spain_in_the_early_70s/
|
{
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"I don't have any sources at hand but I will tell you what I remember from my Spanish High School history lessons:\n\nFranco no longer is the dictator he was at the end of the Civil War, his aging and loosening of the executive power have made him a somewhat ceremonial figure, specially after he appointed his close confidant, admiral Luis Carrero Blanco as prime minister in june 1973. In this time ETA became an active threat, but they almost never made moves on civilians, and targeted mostly politicians and the military, Carrero Blanco himself being one of the casualties.\n\nWhen talking about political issues you have to take into account that all Spanish parties besides Francoist movements were not dead in any way and were active either very discreetly or abroad. People did discuss politics but no real protests or manifestations ocurred because a) censorship was strict and powerful all the way until Franco's death and b) Spain was ending a period of incredible economic and social prosperity. Almost everyone everywhere was happy, had a wealthy lifestyle and managed to do things that many other western nations had done 40 years before, such as buying their own cars, partying, going to concerts and travelling. Tourism BOOMED in Spain, and has not stopped since. It is rumoured also that Francoist authorities somehow managed to rig the Eurovision Song Contest in favor of Spain in 1968, making a singer called Massiel win with an awful song called 'La La La'.\n\nIt was only after Franco's death that the country was somewhat shaken up and had some economic troubles and challenges, but once democracy had been brought back, it would most certainly have seemed that the country had been a stable democratic state in appearance for some time. Cuturally, economically and diplomatically speaking, the country was the same as its neigbours except for the fact that it was a dictatorship. By 1972 people were just waiting for Franco to die."
]
}
|
[] |
[] |
[
[]
] |
|
2ka6ey
|
What will I hear if I talk while breaking the sound barrier?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2ka6ey/what_will_i_hear_if_i_talk_while_breaking_the/
|
{
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"cljp4nl"
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"text": [
"Depends, in a jet it eill sound like you talking, if your head is exposed it will sound like nothing (and you would be screaming neways). What you hear is transmitted through the air (sound is just waves in air). So if the air is contained ans traveling at the same velocity, no change. If it isnt contained all you will hear is the air, and the air friction would be increadibly painful "
]
}
|
[] |
[] |
[
[]
] |
||
bgdvnn
|
Is it possible that society actually needs wars as an engine for progress in technology? What does history say about this?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/bgdvnn/is_it_possible_that_society_actually_needs_wars/
|
{
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"text": [
"This question is so broad, the answer will depend pretty much entirely on what you want it to be. It would be easy to name many cases in which war produced technological innovations, but just as easy to cite many cases in which it didn't. Whichever point you want to prove, you can pick your examples to match. Someone who reads the question and thinks immediately of the World Wars will say \"competitive arms development, and the wartime challenges of logistics and medical care, contribute to technological invention and improvement in ways that might otherwise have taken longer, if they would have happened at all.\" But someone who thinks of, say, the Peloponnesian War might answer \"war is only a destructive force; the priorities and costs of war actually inhibit any technological development that might otherwise have received the necessary funding, manpower and thought.\" Whole swathes of human history attest to the fact that endemic warfare often produces anarchy and poverty, not innovation and technological change.\n\nThis is complicated by the question whether the particular technologies developed in wartime (and for the sake of fighting wars more effectively) actually matter outside of that context. Wars may make a society better at fighting wars, but does that help anyone in society at large? It's easy to point at technologies that were invented for a military purpose and have since made the leap into civilian life; but similarly, it's easy to point at technological innovations (like, say, siege towers or anti-tank shells) that serve only to solve military problems and don't contribute anything to the way people live.\n\nThe guide you offer into these hugely subjective topics is that you're asking whether society *needs* war as a way to propel technological change. The implied assumption is that without wars, such change might not happen at all, or at a much slower rate and in fewer ways. This framing would theoretically allow us to put all of the war-related technology of history onto a big pile and ask (passing by the question whether all of it has a use in society) whether war was needed to produce all that, or whether it would have been developed regardless. But the problem there is that there's no cut-and-dried distinction between \"war tech\" and \"civilian tech.\" They build on each other. For example, the steam engine was invented in an entirely civilian context and applied first in industries like mining and cloth making. But then it was adopted by navies to propel ships, which then kicked off a host of military innovations related to the new energy source. Modern tanks may be marvels of offensive and defensive technology, but the first tanks were designed around readily available agricultural tractor chassis. Does society need war to generate more advanced technology, or does military technology need society to produce things that allow it to develop?\n\nAny answer will inevitably devolve into a chicken-and-egg question. Who actually owes whom for what? Which innovations can militaries wholly claim (especially given that modern military technology is developed in a network of government contracting and liaison with civilian industry)? Can we isolate the improvements made during certain conflicts and can we assume they would not have been made without those conflicts? How do we define \"need\" when we say that society needs warfare to propel technological change?\n\nSuch questions can only be answered on a case-by-case basis. Technological improvements need to be seen in their historical context: not just the when and why of their development, but the origins of their parts and their principles. You don't just randomly come up with radar or nuclear fission to fight wars better. Similarly, society at large doesn't just sit there waiting for the boffins at the War Department to give them these things to play around with. The development of new technology is a process with different people contributing for different reasons - some in the military, some in universities, some in their shed or their study. It's impossible to say categorically which side needs the other to make any progress.\n\nJust as importantly, the mere existence of a military conflict does not speed up military innovation; there needs to be a context in which new technologies are available from other spheres and new technology is thought to offer opportunities for major tactical or strategic advantage. If these conditions are absent, wars will simply be fought in the tried-and-tested manner until one side wins. Many resources will be spent or destroyed in the process. It's not by definition an ideal environment for the development of different technology.\n\nIn short, we can't simply answer this question one way or the other. It is uncontroversial that research spurred on by war has contributed substantially to the improvement of existing technologies and the development of new ones (especially in recent times). After all, people invest ingenuity and resources in things that matter to them, and warfare has tended to matter a lot. On the other hand, it is also uncontroversial that technological innovation happens outside of the military sphere, and that militaries benefit substantially from this. It is also presumably uncontroversial that war is not primarily a creative force, but one mainly interested in enhancing its ability to destroy. Any attempt to resolve these contradictions in a single universal truism about war's influence on technology seems futile to me.",
"There's a bit of determinism wrapped up in this question that I'd like to tackle -- although u/Iphikrates and u/restricteddata have done a good job of delineating how we think of \"technology\" and how it's applied, and how our specific technological-collegiate-military-industrial research-driven era is very much a product of the postwar period -- there's also a bit of an assumption that technology wins wars, and the side that techs the best will win. \n\nI'd like to tackle this by relating the question to ships and shipbuilding, which seems like it's an obvious area where \"better technology\" will win the day. But the weird thing is that the early days of the English (later British) navy's real rise as a power started at least partly because they adopted an inferior technology. \n\nI was reading about cannons the other day, as one does, and I was reminded of a major change in procurement that happened starting around the 1540s in England. Henry VIII was a Renaissance prince in many senses, not least his admiration for and desire to own many large guns. At the time, large cannons were cast from bronze, an alloy of copper and tin; while England (or Cornwall, anyhow) was rich in tin, copper had to be imported or guns themselves imported entire, which was expensive even for someone who dissolved monasteries and seized church property. (Copper was not discovered in England until Elizabeth's reign.) In the 1540s, though, crown investment in gun foundries in the Weald of Kent started to pay off in the form of cast iron guns, the first of which was cast in 1543. \n\nIron is not nearly as good a material as bronze for casting guns. Iron melts at a much higher point than bronze; it is heavier (more dense) than bronze; it is prone to flaws in the casting, which can compromise its strength; the black powder used at the time will corrode the inside of the gun (sulphuric acid is one of its combustion products). \n\nIron guns will also burst without warning, whereas bronze guns will bulge around flaws and then split. This was a major drawback for gunners at the time, who had no way of calculating how much powder and shot a gun might be safely charged with, other than by loading it and firing it off. \n\nBut the crucial advantage iron guns had over bronze ones was that they were substantially cheaper -- medieval England was rich in iron, and iron guns and shot (bronze guns usually used stone shot) were between 10-20 percent of the cost of bronze guns. (The cost of iron guns actually fell by about 20-25 percent, from £10-12 per ton to £8-9 per ton, from 1565 to 1600, in a period of otherwise rapid inflation.) \n\nSo, the iron gun was heavy, of uncertain strength, and prone to bursting without warning; but you could also get 5 or 10 iron guns for the cost of one bronze gun. The Royal Navy was still armed mostly with bronze through Elizabeth's reign, but cheap iron guns were suddenly widely available for smaller ships, including many that straddled the late-Elizabethan line between private commerce, privateering, and piracy. \n\nSo the reason for this rather long-winded answer is to point out that the measures we're often drawn into for what technology is \"better\" don't always match with how the rubber meets the road. The Japanese Zero was a \"better\" aircraft than the Grumman Wildcat for values of \"better\" that value speed, range and dogfighting, but the Wildcat racked up something like a 6:1 kill ratio when pilots fought in pairs and took advantage of their planes' ruggedness. British-built ships in the period I study are [often argued to be \"worse\" than French and Spanish designs,](_URL_0_), yet Trafalgar was so decisive a British victory that it was the last fleet combat for 111 years. Warfighting is not just about the stuff, but also logistics, training, performance and a host of other things."
]
}
|
[] |
[] |
[
[],
[
"https://www.reddit.com/r/AskHistorians/comments/44sivx/ship_design_and_construction_in_the_age_of_sail/"
]
] |
||
3klkpd
|
What do you end up with if you tear something apart at a 'molecular level'?
|
This may seem like an odd question; but we have an add on TV that proudly presents it's product as (a blender) able to tear apart food at a 'molecular level'. Creating 'super infused super food'.
That got me thinking; if you began tearing food items apart at a molecular level; what exactly would you end up with? Would it still be the same substance?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3klkpd/what_do_you_end_up_with_if_you_tear_something/
|
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"Well first, that sounds like garbledeygook ad copy, so I wouldn't put much stock in the scientific value of that TV spot. \n\nAs for what breaking something at a \"molecular level\" would mean, that would depend on the nature of the substance. For crystalline materials, breaking a single crystal, you just get two smaller crystals. For many biological materials, breaking them would just separate some molecules into the respective parts. For large covalently-linked materials like rubber or cellulose, at some point chemical bonds would have to break, meaning you get new \"molecules\", but the nature of those molecules are poorly defined to begin with because the entire mass is connected by covalent bonds. Is that a single molecule? Not by most definitions. \n\nCould a blender break a single small molecule? No. Could it break a larger one like a molecule of nucleic acid or protein? Yes, the shear force could lead to breakage of a bond. Technically a \"different substance\" but with most of the same properties. The more important function of a blender is disrupting the arrangement of various molecules with respect to each other, not their action on individual molecules themselves."
]
}
|
[] |
[] |
[
[]
] |
|
1cyoq4
|
why does money exist?
|
I've been thinking about it, and most problems begin with money.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1cyoq4/eli5_why_does_money_exist/
|
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"Because it's inconvenient to have to trade water buffalo for skittles.\n",
"Less flippantly, it exists because resources are scarce. Money helps us decide how to allocate scarce resources.\n\nFor example: there is a limited amount of beautiful, beachfront property on earth. How do we decide who should get to use that property? Money provides us the answer - whoever is willing to pay the most for use of the property, gets to use it.\n\nIt is important to note that money is just *one possible* system for allocating scarce resources. Money has some advantages, which I will get into. But there are other possibilities. For example, you could allocate scarce resources by decree, with a committee deciding who gets the beachfront property. Or, you could allocate scarce resources by whoever gets it first. Whoever first builds a house on the property gets it. \n\nThe advantage to using money to allocate scarce resources is that money can generally only be made by being a productive member of society. And that means making life better for people, because if you didn't, they wouldn't give you their money! That's the theory, anyway, and plenty of people would disagree with it, but the fact is that it's worked damn well for Western civilization so far, problems and all. Are there *better* ways to allocate resources than money? Maybe! Who knows! Money is certainly very well tested.\n\nSo if you want to do away with money, then you have to come up with an alternate system of allocating scarce resources. Because resources will *always* be scarce. Even if everyone on earth had all the food they wanted, and we somehow managed to make everyone an Xbox 360 and a nice car, beachfront property would still be in limited supply. As would Ferraris and 20 carat emeralds. All of these need to be allocated somehow. How do you propose to do that?",
"The problems you think start with money, actually start with human vices.\n\nThe capitalist - market system would actually work flawlessly, if not for human greed, carelessness, irrationality, gluttony,irresponsibility, lack of respect and care for their fellow humans, inability to think long term, be emphatic and support equality.\n\nWell educated, egalitarian, enlightened and empathic cultures are significantly less prone to have economic problems, and even when they do, the negative impact on human lives is lessened, and spread equally, without significantly harming anyone."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
24chw0
|
how do intangible currencies like bitcoin and dogecoin have value?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/24chw0/eli5_how_do_intangible_currencies_like_bitcoin/
|
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"text": [
"People will accept it for goods and services. Therefore it has value."
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|
[] |
[] |
[
[]
] |
||
r6pma
|
Evolution Debate
|
askscience
|
http://www.reddit.com/r/askscience/comments/r6pma/evolution_debate/
|
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"[Nothing in Biology Makes Sense Except in the Light of Evolution - Theodosius Dobzhansky](_URL_0_)",
"The best \"proof\" for evolution that I can come up with is the fact that we get sick every year. All viruses mutate and \"evolve\" in order to become better resistant to our treatment methods. Every year, a new strain of cold appears that is more resistant to last years medicine.\n\nThis is essentially natural selection in it's purest form. Every year when you take medicine to combat your cold, there is a small amount of the virus that resists the treatment. This small amount is not enough to keep you sick and therefore you recover. However, this small remaining amount then breeds and multiplies until it is the new dominant strain of virus. To my knowledge, this process is one of the easiest ways to validate natural selection.\n\n_URL_0_",
"[Evidence of common descent](_URL_1_) \n[20+ evidences for evolution](_URL_0_) \n[A website with a load of links supporting evolution](_URL_2_)",
"[Laboratory Observed Speciation](_URL_3_)\n\n[A starting point for objections to evolution](_URL_1_)\n\n[Nylon-eating bacteria](_URL_2_) The latter being interesting in that it has apparently evolved enzymes only useful for digesting nylon products, which are not only different from its relatives, but also which would have also obviously been useless before humans invented nylon in the 30's.\n\n[Discussion on the misuse of the scientific terms fact and theory in the evolution debate](_URL_0_)",
"You may be presented with arguments, presented as *fact* that you may not be able to counter if you do not prepare for them.\n\nFor example, it is sometimes claimed there has been insufficient time, given a particular rate of random mutation, to produce the observed complexity in the natural world.\nYou can question the assumptions, such as how many mutations would be required to produce a given complexity, but you won't likely have a better basis to estimate this made-up quantity. You can, however, point to natural selection as a way to amplify the rate of beneficial mutation propagation. That is, the process is not entirely random, more of a go with what works \"survival of the fittest\".\n\nAnother example is that very complex systems could never evolve because intermediate stages are not viable, and would not produce survival benefits.\nI have heard eyes used in this line of reasoning, and point out that there are existing examples of photo-receptive organisms all along the spectrum of \"eyes\", such as deep sea hydrothermal shrimp, copepods, etc.\n\n\n[Here](_URL_0_) is one *point*. And, [here](_URL_1_) is its *counterpoint*.\n\nedit: fixed link (1)",
"[The peppered moth](_URL_0_) is a great and easy to understand example of observable evolution that has been studied in depth.\n\n The moth was originally light grey & splotchy to help it camouflage on the lichen growing on trees. During the industrial revolution the pollution slowly killed off the lichen. The moths that were born with mutations making them a slightly darker shade allowed them a better chance of survival because they could hide from predators better (the trees were black with pollution from coal burning) . Eventually most of the moths born were a dark grey, almost black shade, because the trait of having dark color allowed them to survive and reproduce to pass that trait on.\nNow that the pollution has been cleaned up/less coal burning the numbers of light color moths are starting to increase again.\n",
"This will not be a debate in the sense that both parties do not follow the same rules of debate, nor share the same basis of assumptions.",
"Point out the fact that the theory of evolution is a serious scientific endeavor with multitudes of observations and evidence that all point to the truth of that theory. Then point out that Christianity, Judaism and Islam all tell completely different stories about the exact same God, and how many sects within those religions disagree completely (sometimes violently) about the interpretation of just one source of evidence (i.e. whichever holy text). It's not a matter of believing in evolution, evolution is an observable scientific fact. Saying you believe in evolution is like saying you believe in physics or the water cycle.",
"There's an avalanche of information supporting evolution, but I think the most helpful would be to know weak points for counterarguments like Intelligent Design.\n\nRead Behe's book that entails the concept of 'Irreducible Complexity,' and figure out (or simply do a quick Google search) of why that concept does not work.\n\nGood counterarguments to Behe include 'Arch' theory, which is a good place to start!",
"If you're looking for books, try Why Evolution is True, by Jerry Coyne. [There's an accompanying blog that might be worth reading too](_URL_0_).",
"1) Concrete examples : Lenski's work on the long term evolution expereiment, and vinyl eating bacteria are great examples. Google them; it will show up.\n\n2) Read [this](_URL_0_). I link that all the time; it's a fantastic article, and is readable at the educated layman level. It's not that fact-packed, but it will help you understand the concept a bit better.\n\n3) To counter their arguments, make them prove their opinion at least to the point that evolution has been proven to them; similar levels of rigor. I'm sure your bio textbook has some examples in it, so they need to present data supporting their proposed mechanism at at least the same level of rigor. Introduce them to this concept before you start any discussion.\n\n4) \"God did it because I believe God did it\" doesn't count because you can counter with a statement of equal rigor: \"God didn't do it because I don't believe God did it.\" The way you do this is important, though; when they say that, casually comment that their statement is a bit flippant. When they counter that it isn't, argue that if you used the opposite statement (God didn't do it because I believe he didn't), you would feel uncomfortable as the comment would seem flippant to you. They will disagree to support their stance. Now you can counter with that exact statement.\n\n4) Talkorigins is a great website. It's about as old as the internet, I think.\n\n\n",
"If you explain how evolution works you'll see that it is almost a tautology. Also I just read [this](_URL_0_) which might give you some pointers if you want to convince even those who won't listen to your other arguments.",
"OP said not to focus on just religious counter-points to evolution, but who else doesn't believe in evolution? Or at least who doesn't believe in evolution and has their own point of view on the matter other than \"I don't know.\"\n\nIt would probably be best to focus on the religious points, like irreducible complexity, and it \"violating\" the second law of thermodynamics. \n\nRead through this wiki\n\n_URL_0_\n\nIt should tackle just about everything that you could possibly encounter. \n\nFor points of your own, I find very simple and tangible examples work best. Like how different antibiotics on a petri dish of the same bacteria will kill different sized circles of the bacterial lawn and how that can be analogous to how evolved that bacteria is to resisting that antibiotic. ",
"One type of argument I find very compelling against Intelligent Design is pointing out examples of poor design in some living beings, like the Recurrent Laryngeal Nerve on mammals, particularly on giraffes. \n\n_URL_0_\n\nThe left laryngeal nerve could make a very straight path right into the larynx, but instead it descends down to the thorax, passes through the aortic arch and comes up again to reach the larynx. Imagine this path in an animal like a giraffe: this means that instead of making the straight path of a some 20 - 30 centimeters from the vague nerve to the larynx, it goes down and up again a two meter long neck!! And this introduces some problems: material waste, delays in the nervous impulse reaching the larynx, need for more energy expenses for a sufficiently strong nervous impulse to reach the destination (because of dissipation), etc.\n\nIt's easy to explain this in an evolutionary setting. Fishes don't have necks, so the the equivalent of the larynx nerve make a straight path to its destination through the various blood vessels in the fish thorax. Evolution is constrained to generate new body plans based on the existing ones. It can't just invent something entirely new. New bodies evolve in small steps from the previous existing bodies. And all intermediate states must be viable! So, as mammal necks start growing, the nerve is already stuck with its path through the thorax. Selection would favor an animal with a shorter nerve, but there are not many ways to get from long nerve to short nerve in small viable steps. \n\nAs biologists often put it: evolution is not global optimizer. It must work through small, viable steps on what already exists. \n\nAn intelligent all-knowing designer is not constrained by this! He can just make the perfect animal from scratch. So... how do you explain poor design by a perfect designer? Deliberate sloppiness? \n\n\n\n\n\n",
"When are they going to have the Gravity debate?",
"Evolution is nothing but the change in allele frequency over time, so I'd start with that simple definition. I'd also bring up all the examples of antibiotic resistance such as MRSA.",
"[Index to Creationist Claims](_URL_0_)",
"1. There is no debate, this isn't a popularity contest so unfortunately less intelligent don't get to participate this time\n2. HxNx, x = different numbers, flu strains, different receptors show up each year\n3. DNA viruses, like herpes/HIV, have large genomes to change their protein coat to evade the immune system, aka evolving\n4. Historical evidence of humans, *Homo* species developing bigger brains and growing a bigger skeletal system\n5. HLA B53 gene more frequently found in West African populations, which help against malaria\n6. CCR5-Δ32 _URL_0_ ",
"Depending on the structure of the debate you may want to try to take a more objective view. Your clear bias compromises you...just a thought.",
"Youtube user [CDK007 has done a lot of videos explaining evolution and countering creationist/ID attacks on evolution](_URL_3_).\n\nA few picks:\n\n* [The basics of how evolution works](_URL_1_) / [Part 2](_URL_6_)\n\n* [Clock evolution / argument against a common straw man attack](_URL_4_)\n\n* [Irreducible complexity](_URL_0_)\n\n* [Evolution of the Flagellum](_URL_5_)\n\n* [Why Intelligent Design is wrong](_URL_2_) / [Part 2](_URL_7_)\n\nAlso remember that evolution does not cover where life originated from, only what happens when you already have self replicating organisms. The theory of how life started is a separate theory called abiogenesis.",
"Despite its controversiality and likelihood to be completely opposed to the scientific community, deleting the original post was unnecessary. Now we have no context or 2nd party."
]
}
|
[] |
[] |
[
[
"http://people.delphiforums.com/lordorman/light.htm"
],
[
"http://en.wikipedia.org/wiki/Viral_evolution"
],
[
"http://www.talkorigins.org/faqs/comdesc/",
"http://en.wikipedia.org/wiki/Evidence_of_common_descent",
"http://www.talkorigins.org/origins/faqs-mustread.html"
],
[
"http://en.wikipedia.org/wiki/Evolution_as_fact_and_theory",
"http://en.wikipedia.org/wiki/Objections_to_evolution",
"http://en.wikipedia.org/wiki/Nylon-eating_bacteria",
"http://www.jstor.org/discover/10.2307/2409365?uid=3739680&uid=2&uid=4&uid=3739256&sid=55928612223"
],
[
"http://www.renewamerica.com/columns/fischer/080418",
"http://scienceblogs.com/pharyngula/2008/04/four_bad_arguments_against_evo.php"
],
[
"http://en.wikipedia.org/wiki/Peppered_moth_evolution"
],
[],
[],
[],
[
"http://whyevolutionistrue.wordpress.com/"
],
[
"http://www.springerlink.com/content/21p11486w0582205/fulltext.pdf"
],
[
"http://www.alternet.org/teaparty/154607/How_the_Right-Wing_Brain_Works_and_What_That_Means_for_Progressives/"
],
[
"http://en.wikipedia.org/wiki/Objections_to_evolution"
],
[
"http://en.wikipedia.org/wiki/Recurrent_laryngeal_nerve"
],
[],
[],
[
"http://www.talkorigins.org/indexcc/list.html"
],
[
"http://www.eeb.ucla.edu/Faculty/Novembre/GalvaniNovembreMicInf2005.pdf"
],
[],
[
"http://www.youtube.com/watch?v=LZdCxk0CnN4&feature=plcp&context=C4127bf8VDvjVQa1PpcFMBUQaLKUoot46DL6oqkdZJGxBIlqqvAio=",
"http://www.youtube.com/watch?v=SeTssvexa9s&feature=plcp&context=C4c8ed02VDvjVQa1PpcFMBUQaLKUootxs0FOv6hpKs4w2ctLa4uXA=",
"http://www.youtube.com/watch?v=M2SVMKZhV2g&feature=plcp&context=C4b4f2ddVDvjVQa1PpcFMBUQaLKUoot1YZxitf4V2jOj1lKEg99uc=",
"http://www.youtube.com/user/cdk007/videos",
"http://www.youtube.com/watch?v=mcAq9bmCeR0&feature=plcp&context=C429e08eVDvjVQa1PpcFMBUQaLKUootwiXVKWx8teC7bI6PiflIIQ=",
"http://www.youtube.com/watch?v=SdwTwNPyR9w&feature=plcp&context=C4ee3d94VDvjVQa1PpcFMBUQaLKUoot7AOvZsTnMwGdypzLSiBF9o=",
"http://www.youtube.com/watch?v=26dwfZIqfco&feature=plcp&context=C4883b92VDvjVQa1PpcFMBUQaLKUoot_TqiJIXiZDBmo6riWWO31A=",
"http://www.youtube.com/watch?v=xx5t5_trnuU&feature=plcp&context=C448b5d5VDvjVQa1PpcFMBUQaLKUoot2FH-6F4uRQUCalCudiEa3g="
],
[]
] |
||
1mi7am
|
in u.s., "math". in u.k., "maths". why?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1mi7am/eli5_in_us_math_in_uk_maths_why/
|
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"They're both shortened forms of the word \"mathematics\". Americans just shorten the whole word indiscriminately, while the rest of the world keeps the plural *s* and shortens the root of the word. ",
"Linguists discuss the math vs. maths wording: _URL_0_"
]
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|
[] |
[] |
[
[],
[
"http://www.youtube.com/watch?v=SbZCECvoaTA"
]
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||
229yxj
|
if number of offspring in mammals roughly correlates with mammary glands, why are twins not the predominant birth in humans?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/229yxj/eli5_if_number_of_offspring_in_mammals_roughly/
|
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"text": [
"Due to bilateral symmetry (animals being roughly symmetrical down the middle) all mammals, as far as I know, have an even number of nipples, even ones where only one offspring at a time is the norm."
]
}
|
[] |
[] |
[
[]
] |
||
3ltm0c
|
How did the combatant nations of WW2 disarm their soldiers when fighting ended? Did lots of soldiers hold on to their weapons, and/or take sidearms home with them? How much military hardware was unaccounted for?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3ltm0c/how_did_the_combatant_nations_of_ww2_disarm_their/
|
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"It depended on the country. I can shed some light on the American and Soviet methods of disarmament.\n\nWhen the Red Army began to demobilize large formations of its troops, the Soviet officials told them to hand over any firearms (government issue or enemy capture) or face potentially being sent to a labor camp. The Soviet government was very careful about how it went about demobilizing its vast army. Its troops had been exposed to capitalist societies, the shortcomings of the government during wartime, and many had witnessed/participated in atrocities that would tarnish the image of the Red Army soldier which was so essential to Russian post-war propaganda. Though the government bestowed numerous gifts upon discharged troops, every soldier who was demobilized also had his/her bag searched on the train before arriving back home. Most did not put up too much resistance to this action because there were still so many weapons and explosives laying about the numerous battlefields back home in Russia. (Source: Ivan's War by Catherine Merridale, pp. 356-357)\n\nIn the American military, soldiers were officially allowed to take home one souvenir firearm, and they had to register it before departing back home. The lines to do so were pretty long at places like Camp Lucky Strike in Le Havre, and many soldiers sold off what extra weapons they had. I don't know what the policy was for service weapons or if a service member could send weapons through the mail before being sent to demobilization camps. It wouldn't surprise me if they did.",
"I can help a bit with Finland. [EDIT: improved sources.]\n\nThe Finnish army was disarmed essentially in two phases: the interim peace treaty signed 19 September 1944 stipulated that the army must be demobilized from its peak of over 500 000 troops to peacetime strength of 43 000 in 2.5 months. The latter part, mostly comprised of the youngest troops, still fought in the Lapland War against the retreating Germans. Additionally, the paramilitary Civil Guard had to be dismantled, and with it its own depots and stored weapons.[1]\n\nPlanning for demobilization began as soon as the Continuation War began in 1941 [1], as the chaos following the First World War was still within memory and everyone wanted to avoid that. There were fears of widespread unemployment, housing crisis and problems when men returned to their workplaces after years of absence. In principle, they had a legal right to return to their pre-war places of work, but as you can imagine many of those posts had been filled during the war for example.[2] \n\nIn practice, Finnish units first moved on foot and by rail to the local area where they had been raised, and demobilized there. At designated demobilization points, the men turned in their weapons and other gear; they could keep their uniforms (with epaulettes cut off) and shoes, but had to turn in hats and belts.[1] (After the war, probably the most common menswear was the old uniform jacket, or something made from it.)\n\nIn principle, every weapon had to be turned in, including those captured from the enemy. In practice, quite a few men had already, during the war, smuggled captured trophies back home on leave for example; these trophy guns (mostly pistols) still turn up from old homes and estates. Hiding war trophies was illegal, but many officers seemed to turn a blind eye to that as long as it wasn't overtly conspicuous; on the other hand, I've heard of one sergeant for example who was court martialed, fined severely and demoted to private for hiding captured binoculars. \n\nHowever, there was also semi-official squirreling away happening: the so-called Weapons Cache Case.[3] Afraid of Soviet designs for Finland, high-ranking officers selected trusted men and began secretly caching equipment for guerrilla war all around Finland. The goal was to gather enough weapons, equipment and supplies for 8000 men, but after careful planning, in a few days enough equipment and food had been cached for about 35 000 men in over 1300 caches all around the country. Most of these weapons were obtained from demobilization depots and had been marked as \"damaged beyond repair\" or \"lost\" in official accounts. The operation came to light in spring 1945, and most of the weapons were returned to depots. However, it seems that as the caches were being cleared, at least some of the weapons went missing entirely - taken by men involved, as final \"life insurance.\" There have been cases where a SMG or even a light machine gun turns up during renovation, although these are rare nowadays. \n\nAccording to Finnish Police, substantial but unknown percentage of illegal firearms in Finland - estimated to be some tens of thousands in total - are thought to be old war trophies, even though thousands have been collected through amnesty legislation. As said, pistols such as Nagant feature prominently.\n\nSources: \n\n[1] master's thesis of officer cadet Ratinen, J. (2009) *Suomen Puolustusvoimien liikekannallepanokyky sodan jälkeisinä vuosina.* National Defence College, Helsinki. Particularly pp. 19-23, also pp. 31-34 for Weapons Cache Case.\n\n[2] Holmila, A. and Mikkonen, S. (2015) *Suomi sodan jälkeen: Pelon, katkeruuden ja toivon vuodet 1944-1949.* Jyväskylä: Atena. Chapter 1 in particular. \n\n[3] Lukkari, M (1992): Asekätkentä (3. täydennetty painos). Helsinki: Otava."
]
}
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[
[],
[]
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5a8de6
|
why is a fan higher pitched when on higher speeds?
|
I'm curious why a fan sounds like it's higher pitched on higher speeds. Does this effect apply to other things? And is the sound we hear air particles moving more quickly? (Not 100% sure if this is a physics question but that seems right...).
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5a8de6/eli5_why_is_a_fan_higher_pitched_when_on_higher/
|
{
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"text": [
"Sounds are based on frequency. The greater the frequency, the higher the pitch of the sound. As the fan is spinning faster, its frequency is greater and therefore the sound is higher."
]
}
|
[] |
[] |
[
[]
] |
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8s7i6p
|
why during medical trials both control and subject group are told they are receiving experimental drug instead both being told they receive placebo?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8s7i6p/eli5_why_during_medical_trials_both_control_and/
|
{
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"text": [
"Telling people you're feeding them sugar pills when in fact they're taking an experimental drug with possibly disastrous side effects is considered unethical, as it will make them more likely to shrug off bleeding from their ears and eyes as \"probably just allergies or something.\" \n\nTelling people you're feeding them an experimental drug when in fact you're just giving them sugar pills is less likely to do any harm. ",
"Adding to the other comment, when it eventually goes public, the people will be told they are receiving the actual drug and not just a placebo. It helps both groups stay in the correct state of mind",
"AFAIK during clinical trials participants are not told anything about which of the two they're getting. As far as they know, they could either be getting the real drug or the placebo, and they won't be told which it is/was until after the trial is completed. Telling people they're getting the real drug when they're not (which would be true for the control group) would be very unethical. Did you hear/read somewhere that this was how it worked? ",
"I’ve never heard of a study where the subjects are told they definitively are going to get one or the other, and possibly take the other. This would be considered unethical. An ethical study is one where the subjects are told they *may* get the placebo or drug beforehand. Thereon the best kind of subject is where both the subjects and researchers don’t know who got what until the end. Now having said all that I can answer the question. The power of suggestion is quite strong and the psychosomatic effects (mind effecting the body) of either a placebo or nocebo (opposite of placebo - where you perceive a negative effect from something which shouldn’t normally), can really make or break a study. In that sense it wouldn’t be a good control if you said everyone was told it was the drug or not. Because you couldn’t tell that it actually was the drug or not, or a placebo or nocebo. Again, this is why the best studies are when subjects and researchers only know who was given what until after the study. In that sense you will only be looking at raw data in all possible circumstances. What your looking at then, is a subject who only reports what they feel/effects, completely unknown. Sure there will be people who make up there own minds, but because it’s not already based on a prejudiced expectation of what they ‘believe’ the pill to be, the data is much more valuable. "
]
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|
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[
[],
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||
2bhon2
|
- why do most honour killings involve murdering the victim? why not kill the rapist instead?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2bhon2/eli5_why_do_most_honour_killings_involve/
|
{
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"text": [
"In such cultures women are viewed as property, to be bought, sold, or traded. The honor killing is in retribution for the perceived dishonor of allowing themselves to be raped, as it damages or destroys their value to their male owner.\n\nIt is fucked up.",
"If someone smashes the windows in your car, take a shit in it, slashes the tires you would get a new car, it was just property damage. Maybe youll find the dude who did this but either way that car is useless. \n\nMost of these cultures view women as property so not only should it be replaced but its broken goods, so broken you have to set the car on fire so your neighbors dont give you shit for having a smashed up wreck in your driveway. ",
"Because it's not about the act, or the property being damaged, or the people involved. \n\nIts about maintaining family honour, and removing the mark against the family. The girl doesn't factor into it at all, because she was supposed to protect herself, and the family was supposed to help her do that. They failed, and so it has brought shame ~~too~~ to the family. To rectify, they destroy the evidence of shame to remove the mark on the family. \n\nMost Muslims do not believe in honour killings, by the way, nor do any sects therein publicly accept them as part of their faith.",
"Because even if you are the victim and you got raped, you still had sex outside of (or before) your marriage, which means you dishonored your family. This dishonor sticks to the family, and you, for the rest of your lifetime. Thus they significantly shorter your lifetime.\n\nAlso because the people that thought up these religious rules were like superhigh on acid.",
"The real issues here are the twin concepts of dishonor and atonement. \n\nWhat is dishonor? Dishonor is a state of extremely depreciated social value within your community. Each society treats their 'dishonored' differently. Some societies have legal and social rules to protect their dishonored from too much abuse, while other societies essentially revoke their rights and encourage everyone to treat them as an open target. \n\nWho determines what is dishonorable in a society? Well, every member of a society who expresses their opinions on dishonor 'votes' for what their society defines as dishonorable. When enough of a society are in agreement, their beliefs gain momentum and trample any competing beliefs to establish a cultural norm that is difficult to change. Different societies come up with widely different beliefs about dishonor.\n\nAtonement is an act that that a society has collectively agreed will alleviate or remove someone's status of dishonor. Societies with especially draconian beliefs about dishonor often develop strong concepts of atonement. Different societies come up with widely different beliefs about atonement.\n\nCultures with honor killings tend to have a couple things in common:\n* they collectively treat their dishonored very very poorly\n* dishonor is transmissible through association. A dishonored person automatically passes their dishonor onto their family.\n* women are poorly protected in both legal rules and social rules.\n\nAs for the ELI5, why do most honor killings involve murdering the victim? Why not kill the rapist instead?\n\nThe areas where honor killings developed have well established legal rules and social rules that make it very hard for women to pursue justice against male perpetrators. These societies have long-held and sacred beliefs that men are inherently honorable and women aren't, and they have written their laws as if it were a fact that women were inherently untrustworthy. Because men are deemed to be more honorable then women, any evidence they produce in court will be weighted as more significant. The evidence demanded from women is overwhelming and often impossible to supply. This makes it almost impossible for women to get justice against men in the courts. On top of that, because society views women as being innately less honorable then men, the general population is quick to condemn any woman who visably seeks justice in the courts. They are almost automatically assumed to be a liar who is seeking to ruin the reputation of an innocent man, and they will be treated as such. This makes it painful for women to even pursue the justice that they probably won't get.\n\nOn top of all this, women in these societies aren't really considered free people, they are considered property of men and are owned by either a father or a husband. Rape, for all intents and purposes, is treated as a property crime in these cultures. The victim of rape isn't the woman, it is the man who owns her. A sexually impure woman is considered dishonored in these cultures, which ultimately means she has lost her trade value and will be treated worse by society. And if that weren't enough injustice, these cultures also believe that her dishonor is transmitted directly into her family. Her father suffers from her dishonor, her husband, her children.\n\nKnowing all this, imagine your daughter has been raped. You know that you can't get justice in the courts, and that if the word gets out both here and yourself will be dishonored. The obvious decision is to hush it all up, but it is too late, you daughter already confided in her friends and now the word is out on the street. People are starting to talk about your liar daughter, calling her a whore and saying that probably tempted that nice boy to destroy his life. The word gets out further and you now in the discussion as the disgraced father of a lying whore. Suddenly no one seems to be buying anything from your shop and none of your friends are calling to invite you out to dinner. You can't go after the man, he is utterly protected by the law, besides all of this is probably because of her flirtations. How do you even know she was even raped? She could have made it all up. For all you know she might be a lying whore who would destroy your life for a fast fuck, then come to you afterwards with a fake story and crocodile tears in her eyes. Everyone knows that women can't be trusted, hell the whole of society is grounded on the knowledge that you can't trust women. This wretched whore has made a mockery of your trust and humiliated you in front of the whole town. This dishonor is all her fault, but only you have the power to atone for it. Your society has collectively agreed that you can atone for this dishonor by showing the strength and courage to destroy the thing that ultimately dishonored you; your daughter. \n\ntl;dr Daughters are replaceable in exactly the way that honor isn't."
]
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[],
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