question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
|---|---|---|
why does the us use fahrenheit when the rest of the world uses celsius? | 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.
*oh my god metric's haaaard, man!* | [
"The Fahrenheit scale was the primary temperature standard for climatic, industrial and medical purposes in English-speaking countries until the 1960s. In the late 1960s and 1970s, the Celsius scale replaced Fahrenheit in almost all of those countries—with the notable exception of the United States—typically during... |
how can a country sell bonds with negative interest rate? | They can't and don't.
The 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. | [
"During the European debt crisis, government bonds of some countries (Switzerland, Denmark, Germany, Finland, the Netherlands and Austria) have been sold at negative yields. Suggested explanations include desire for safety and protection against the eurozone breaking up (in which case some eurozone countries might ... |
what's the process to get into u.s from mexico legally (immigrate)? | 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)
After 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.
Employers 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.
All 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).
Generally, if you h ave no special skills then you will not be granted a green card. | [
"After the United States returned to a more closed border, immigration has been more difficult than ever for Mexican residents hoping to migrate. Mexico is the leading country of migrants to the U.S.. A Mexican Repatriation program was founded by the United States government to encourage people to voluntarily move ... |
Why do some places have two high and two low tides a day, and other places have only one? | 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.
There 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 | [
"Tides are commonly \"semi-diurnal\" (two high waters and two low waters each day), or \"diurnal\" (one tidal cycle per day). The two high waters on a given day are typically not the same height (the daily inequality); these are the \"higher high water\" and the \"lower high water\" in tide tables. Similarly, the t... |
what is academic probation and how would somebody get it? | It means your grades are shit and if you don't shape up you're out.
This is more typical in colleges or private schools since they don't want some slacker tanking their performance numbers. | [
"Academic probation in the United Kingdom is a period served by a new academic staff member at a university or college when they are first given their job. It is specified in the conditions of employment of the staff member, and may vary from person to person and from institution to institution. In universities fou... |
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? | 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.
The 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*. | [
"Edward III of England's son, Edward the Black Prince, invaded France from English held Gascony in 1356, winning a victory at the Battle of Poitiers. During the battle, the Gascon noble Jean III de Grailly, captal de Buch, captured the French king, John II, and many of his nobles. At the instigation of the pope, ne... |
How common was it to be executed for being a "witch" around the time of the Salem Witch Trials? | 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.
Different 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.
England'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.
In 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.
Trials 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.
The total number of executions is usually estimated to be around 40 to 50,000, but higher estimates do exist. | [
"The Salem witch trials of 1692 touched Topsfield directly. Belief in witches was normal in the seventeenth century. People were accused of witchcraft in Europe and the colonies during this time, but executions were relatively rare in the colonies. Historians conclude that only fifteen people were executed as witch... |
Has the water released by combusting hydrocarbons had any effect on the environment? | 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.
Generally, 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.
So 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. | [
"Hydrocarbon exploration in deep water occasionally results in significant environmental degradation resulting mainly from accumulation of contaminated drill cuttings, but also from oil spills. While the oil gusher involved in the Deepwater Horizon oil spill in the Gulf of Mexico originates from a wellhead only 150... |
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'? | 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.
When 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. | [
"\"Many appliances continue to draw a small amount of power when they are switched off. These \"phantom\" loads occur in most appliances that use electricity, such as VCRs, televisions, stereos, computers, and kitchen appliances. This can be avoided by unplugging the appliance or using a power strip and using the s... |
why don't stars appear red but white? It is said that only red colour sustains when light travels a long distance! | 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.
However, 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. | [
"Interstellar reddening occurs because interstellar dust absorbs and scatters blue light waves more than red light waves, making stars appear redder than they are. This is similar to the effect seen when dust particles in the atmosphere of Earth contribute to red sunsets.\n",
"In astronomy, a green star is a whit... |
To what extent did Alexander the Great/Hellenism pave the way for Christianity? | 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.
Why it’s wrong:
Early 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.
Enter 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.
Why it’s right:
Ok 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.
Basically, 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.
| [
"Alexander (fl. 50–65) was a Christian heretical teacher in Ephesus. Hymenaeus and Alexander were proponents of antinomianism, the belief that Christian morality was not required. They put away—\"thrust from them\"—faith and a good conscience; they wilfully abandoned the great central facts regarding Christ, and so... |
Why do some smells travel faster and propagate farther than others? | 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. | [
"Sound typically travels fastest and farthest through solids, then liquids, then gases such as the atmosphere. Sound is affected during fog conditions due to the small distances between water droplets, and air temperature differences.\n",
"A simple example concerns the model on which aether was originally built: ... |
At what altitude does the sky cease to be blue? | I will answer your question with a question.
At what point does the red become blue in the following image?
_URL_0_ | [
"When the sun has just set, the brightness of the sky decreases rapidly, thereby enabling us to see the airglow that is caused from such high altitudes that they are still fully sunlit until the sun drops more than about 12° below the horizon. During this time, yellow emissions from the sodium layer and red emissio... |
Is there a lot of variance between people in how much energy they are able to extract from food they digest? | 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."
Studies 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.
There'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.
The 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.
**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.
EDIT: In the spirit of procrastination from what I _should_ be working on, I added more details and cited one of the foundational studies. | [
"The energy input to the human body is in the form of food energy, usually quantified in kilocalories [kcal] or kiloJoules [kJ=kWs]. This can be related to a certain distance travelled and to body weight, giving units such as kJ/(km∙kg). The rate of food consumption, i.e. the amount consumed during a certain period... |
how do we know the articles from /r/politics and anything the media shows is actually real? | 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. | [
"The show also addresses questions about how the media is influenced or spun by politicians, corporations, and interest groups with the intent to shape public opinion. This includes an \"OTM\" feature that covers the media's use of terminologies that may engender biased points of view, and the use of hot-button iss... |
How populist was the American revolution? Was it a movent by the elites or did the lower classes support it? | 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.
To 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:
> 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.
Yeah, not very flattering, is it? However, his views eventually evolved as the situation in America became more severe.
By 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.
Between 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.
That'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.
Now 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.
Tl;Dr: Most founders dragged their feet as the American "mob" dragged them forward .
Edit: fixed a misspelled name. | [
"Anti-establishment populist politics became an important political force in 19th century Ontario amongst rural and working class political activists who were influenced by American populist radicals. Populism also became an important political force in Western Canada by the 1880s and 1890s. Populism was particular... |
why would a country implement negative interest rates (ie. japan) | 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. | [
"Since the 1990s, the Bank of Japan, the country's central bank, has kept interest rates low in order to spur economic growth. Short-term lending rates have responded to this monetary relaxation and fell from 3.7% to 1.3% between 1993 and 2008. Low interest rates combined with a ready liquidity for the yen prompted... |
How common is it for a planet to have a natural satellite like our moon? | 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.
What'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.
The 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.
The 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.
Regarding 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. | [
"Although no other moons of Earth have been found to date, there are various types of near-Earth objects in 1:1 resonance with it, which are known as quasi-satellites. Quasi-satellites orbit the Sun from the same distance as a planet, rather than the planet itself. Their orbits are unstable, and will fall into othe... |
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? | 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. | [
"Mirror matter could have been diluted to unobservably low densities during the inflation epoch. Sheldon Glashow has shown that if at some high energy scale particles exist which interact strongly with both ordinary and mirror particles, radiative corrections will lead to a mixing between photons and mirror photons... |
Is it possible to for the body to stop identifying an allergen as harmful after years of no exposure? | 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. | [
"The symptoms of allergic contact may persist for as long as one month before resolving completely. Once an individual has developed a skin reaction to a certain substance it is most likely that they will have it for the rest of their life, and the symptoms will reappear when in contact with the allergen.\n",
"Th... |
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? | 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. | [
"In the first close presidential election since the 1812 election, four major candidates ran, all of whom were members of the Democratic-Republican Party. The Democratic-Republicans had largely been successful in fielding only one presidential candidate in previous elections (except in 1812), but the breakdown of t... |
why do humans drink so much water when compared to cats/dogs? | Humans sweat while most other animals with fur/feathers don't. Obviously you need to replace the moisture lost by sweating.
Efficency 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. | [
"BULLET::::- There have been relatively few studies on the preferences of wild animals. A recent study has shown that feral pigeons do not discriminate drinking water according to its content of metabolic wastes, such as uric acid or urea (mimicking faeces- or urine-pollution by birds or mammals respectively).\n",
... |
Is it really possible to "utilize the natural electric currents within the earth" and convert it into "radiant electricity?" | 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.
Also, 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.
I 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.
| [
"A solar photovoltaic power plant converts sunlight into direct current electricity using the photoelectric effect. Inverters change the direct current into alternating current for connection to the electrical grid. This type of plant does not use rotating machines for energy conversion.\n",
"BULLET::::- Renewabl... |
why have salaries not increased on par with the cost of living. | 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. | [
"According to an October 2014 report by the Pew Research Center, real wages have been flat or falling for the last five decades for most U.S. workers, regardless of job growth. Bloomberg reported in July 2018 that real GDP per capita has grown substantially since the Great Recession, but real compensation per hour,... |
Flairs, posters, lurkers, lend me your ears! I come to praise our NEW MOD! | 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! | [
"Mad Mod is a psychedelic red-headed British villain with the mannerisms of a strict schoolmarm, whose root source of power comes from his ruby-tipped cane. It is later revealed that Mod is actually an old man who is given to the use of holograms of his younger self. He is also formidable for his use of hypnotic su... |
What exactly happens when cake batter turns into fluffy, moist cake? | 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.
The 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'. | [
"When the cake has finished baking, it should have a golden brown color on the exposed area. This is due to Maillard browning reactions. If the cake bakes for too long, more moisture will be removed and the texture will turn out dry, rough, and potentially burnt.\n",
"A cake can fall, whereby parts of it sink or ... |
why aren't siblings born with the same dna? | 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). | [
"Theoretically, there is a chance that they might not share genes. This is very rare and is due to there being a smaller possibility of inheriting the same chromosomes from the shared parent. However, the same is also theoretically possible for full siblings, albeit (comparatively) much less likely. Because of the ... |
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. | 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.
Pictures 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.
Video 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. | [
"A binary image can be stored in memory as a bitmap, a packed array of bits. A 640×480 image requires 37.5 KiB of storage. Because of the small size of the image files, fax machine and document management solutions usually use this format. Most binary images also compress well with simple run-length compression sch... |
why does taking (something) to the negative power give us 1/(something)? | If you can realise that multiplication is the inverse of division, then it is pretty easy.
For positive powers:
2^1 =1x2=2
2^2 =1x2x2=4
2^3 =1x2x2x2=8
and so on. For a positive power, you multiply the number.
A negative power has the same pattern, except with division, so:
2^-1 =1/2
2^-2 =1/2/2=1/4
2^-3 =1/2/2/2=1/8
and so on. | [
"Referent power in a negative form produces actions in opposition to the intent of the influencing agent, this is the result from the agent's creation of cognitive dissonance between the referent influencing agent and the target's perception of that influence.\n",
"If the metaphor can be extended, and good and ev... |
the annoying sound in my ears when i get out of the shower. | > 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.
If 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.
If you mean some sort of ringing sound, then I'd suggest you look at [ELI5 : Tinnitus](_URL_0_). | [
"BULLET::::- Bathtub - A teenage girl in her bathrobe talks on her cell phone while looking into her bathroom mirror. She says, \"yeah, my parents think I'm sleeping at your house\". She hangs up and gets into the shower. While showering, she looks down and sees a trickle of blood. She turns around and screams; the... |
Can a collapsing star have such great mass that the black hole formed completely absorbs the supernova and the star simply "goes dark?" | Yes, but it is not really due to the size of the star (given that the star is massive enough to undergo core collapse).
Once 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.
What 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.
[Here](_URL_0_) under Current Models, Core Collapse is a nice chart giving a general overview of size/properties, type of supernova and remnant. | [
"One hypothesis is that the core of the star collapsed to form a black hole. The collapsing matter formed a burst of neutrinos that lowered the total mass of the star by a fraction of a percent. This caused a shock wave that blasted out the star's envelope to make it brighter. After the idea that a black holes are ... |
How do white bloodcells know what to attack? | 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!
& #x200B;
First, 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!
& #x200B;
When 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.
& #x200B;
You 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.
In 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!
& #x200B;
This 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.
& #x200B;
B 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.
& #x200B;
I 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.
& #x200B;
Also 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! | [
"At least eight species (\"P. asio\", \"P. cornutum\", \"P. coronatum\", \"P. ditmarsi\", \"P. hernandesi\", \"P. orbiculare\", \"P. solare\", and \"P. taurus\") are also able to squirt an aimed stream of blood from the corners of the eyes for a distance of up to . They do this by restricting the blood flow leaving... |
the difference between deductive and abductive reasoning. | It simply means coming up with ideas to explain things we see. Those ideas then are put to the test and discarded or validated.
- Deduction: Winter is cold. Winter starts next month. So it will be cold next month.
- Induction: Last winter was cold, the one before was cold, and so on. So next winter is probably going to be cold.
- 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 differs from abductive reasoning by the direction of the reasoning relative to the conditionals. Deductive reasoning goes in the \"same direction as that of the conditionals, whereas abductive reasoning goes in the opposite direction to that of the conditionals.\n",
"Abductive reasoning is a ... |
How realistic is the cancer "vaccine" talked about recently? | 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.
What 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.
The 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.
It'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.
ETA: thank you kind, golden stranger!
...strangers! | [
"The National Cancer Institute states \"Widespread vaccination has the potential to reduce cervical cancer deaths around the world by as much as two-thirds if all women were to take the vaccine and if protection turns out to be long-term. In addition, the vaccines can reduce the need for medical care, biopsies, and... |
Why do radar dishes need to spin and scan the area progressively? Can't they design a radar which scans the whole area? | 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.
You 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:
* 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.
* 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..
Edit: bullet points ftw | [
"Classic radars measure range by timing the delay between sending and receiving pulses of radio signals, and determine the angular location by the mechanical position of the antenna at the instant the signal is received. To scan the entire sky, the antenna is rotated around its vertical axis. The returned signal is... |
What were some tools and technology utilized in the Golden Age of Arctic Exploration? | Depending on the snow (incline, thickness) short and long skis (used by Amundsen on his South Pole expedition and Nansen's Farthest North expedition).
Snowshoes (Fridtjof Nansen's Crossing of Greenland)
Sledges to haul provisions - dragged by either men or sled dogs (again, Amundsen South Pole and Fridtjof Nansen North Pole expeditions).
Robert 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.
Pemmican -- 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.
For 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).
Tents 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).
Boots 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.
*"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)
For a certain type of boot called 'finnesko', Nansen claimed the best were made out of reindeer leg skin from a buck.
Additionally, 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_)
In rain and blizzards, they would also wear a thin canvas overcoat to keep dry.
A 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.
Speaking 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.
Seals (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)
Motors 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)
For 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.
Usually 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.
Straight out of Farthest North (1897):
*"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."*
sources: "Farthest North (1897)" by Fridtjof Nansen. "South Pole (1912)" by Roald Amundsen. "First Crossing of Greenland (1880)" by Fridtjof Nansen. | [
"The Arctic small tool tradition is a broad cultural entity that developed along the Alaska Peninsula, around Bristol Bay, and on the eastern shores of the Bering Strait around 2,500 BCE (4,500 years ago). These Paleo-Arctic peoples had a highly distinctive toolkit of small blades (microblades) that were pointed at... |
what are apertures, f-stops, how does depth of field work, and how does lens measurement factor into the equation? | 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.
As 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.
Since 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.
f-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. | [
"In photography, depth of field (DOF) means an effective focal length. It is usually used for stressing an object and deemphasizing the background (and/or the foreground). The important measure related to DOF is the lens aperture. Decreasing the diameter of aperture increases focus and lowers resolution and vice ve... |
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? | 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.
You can see it one some electronics when you unplug them and the LED slowly fades out rather than going blank entirely. | [
"The products have built-in security codes for controlled activation. Once the code has been input into the device, it is activated for a time period of 8, 12, or 24 hours. Upon expiration of the time clock, the device shuts off and cannot be used again until the code is re-entered. This prevents unauthorized use i... |
What advice can askhistorians give me on becoming a professional historian. | 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_). | [
"The work explores the craft of the historian from a number of different angles and discusses what constitutes history and how it should be configured and created in literary form by the historian. The scope of the work is broad across space and time: in one chapter, for instance, he cites a number of examples of e... |
Why so much variation in the spelling of Irish surnames? | 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.
That 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.
Now 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).
That'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. | [
"A further reason for the variety in anglicised forms of the surname can be explained, as Irish Catholic priests, whilst literate, were only required to record surname spellings phonetically on birth certificates. This led to individuals sometimes having their surname recorded with a different spelling from their f... |
Would it be possible to create a stable, artificial ring around our planet (any celestial body, really)? | 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.
Lets 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.
If 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.
edit: forgot to add earth to the radius of geosync | [
"BULLET::::- A Ringworld (or Niven Ring) is an artificial ring encircling a star, rotating faster than orbital velocity to create artificial gravity on its inner surface. A non-rotating variant is a transparent ring of breathable gas, creating a continuous microgravity environment around the star, as in the eponymo... |
why do brass instruments only emit a sound when pursing your lips? why can't you just blow into them and make sound? | 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. | [
"Many brass instrumentalists argue that excessive mouthpiece pressure is a major cause of embouchure problems and can be a factor in causing embouchure collapse. However, the pressure of the mouthpiece is not static during playing: it increases the higher in the register a player plays and the louder volume level. ... |
What type of wood was the medieval trebuchet made of? | 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.
Once 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. | [
"BULLET::::- Trebuchet: Trebuchets were probably the most powerful catapult employed in the Middle Ages. The most commonly used ammunition were stones, but \"darts and sharp wooden poles\" could be substituted if necessary. The most effective kind of ammunition though involved fire, such as \"firebrands, and deadly... |
Are quarks affected by magnetic fields? | Yes, though quarks are never found alone.
Anything with electric charge can be affected by a magnetic field.
A proton is made of two up quarks and a down quark; it has a charge of +1.
The up, charm, and top quark have a charge of +2/3. The down, strange, and bottom quark have a charge of -1/3. | [
"In the theory of quantum chromodynamics, magnetic catalysis can be applied when quark matter is subject to extremely strong magnetic fields. Such strong magnetic fields can lead to more pronounced effects of chiral symmetry breaking, e.g., lead to (i) a larger value of the chiral condensate, (ii) a larger dynamica... |
how does my printer know how much ink is in the cartridge? | 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.
| [
"All types of compatible ink cartridges are different and vary from supplier to supplier. This is due to the type of ink in the printer, the chips (or no chip) on the cartridge and the actual manufacture of the cartridge itself.\n",
"BULLET::::- \"Injecting ink\": Depending on the type of cartridge being refilled... |
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 | 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:
_URL_0_
EDIT: grammar | [
"In scientific research, misappropriation is a type of research misconduct. An investigator, scholar or reviewer can obtain novel ideas during the process of the exchange of ideas amongst colleagues and peers. However, improper use of such information could constitute fraud. This can include plagiarism of work or t... |
Was former L.A. Mayor John Porter a member of the Ku Klux Klan? | 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).
I also found a [1931 news article](_URL_2_) that mentions it, charging him with "bias to Jews, Blacks and Negroes."
Michael Newton's [White Robes and Burning Crosses: A History of the Ku Klux Klan from 1866](_URL_1_) mentions him.
You 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. | [
"BULLET::::- December 24 – The Ku Klux Klan is formed by six Confederate Army veterans, with support of the Democratic Party, in Pulaski, Tennessee, to resist Reconstruction and intimidate \"carpetbaggers\" and \"scalawags\", as well as to repress the freed slaves.\n",
"The Ku Klux Klan, was founded in 1865 in Pu... |
How come we can see distant galaxies but just recently discovered Pluto's fifth moon? | 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.
It's kindof like how you can see a streetlight from miles away at night, while you can't see the rock 10 feet away. | [
"In July 2015 NASA published photographs taken as the New Horizons space probe passed within 7000 miles of Pluto. A photo of Pluto's largest moon, Charon, shows a large dark area near its north pole. The dark area has been unofficially called Mordor Macula.\n",
"Since the first blurred images of the moon , images... |
how much money (usd) would need to be "destroyed" in order to see a significant rise in the value of the dollar? | _URL_0_
The monetary base went from ~800 billion USD in 2008 to 3.6 trillion 2013 and you had ~10% cumulative inflation over 5 years.
So 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.
It'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. | [
"Estimates put the dollar damage at approximately $230 million to $280 million for California, Oregon and Washington combined. Those figures in 1962 dollars translate to $1.8 Billion to $2.2 Billion in 2014 Dollars. Oregon's share exceeded $200 million in 1962 dollars. This is comparable to land-falling hurricanes ... |
what is the purpose of that transparent blue strip on the top of the windshield glass of almost every car? | 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. | [
"Dichroic glass has one or several coatings in the nanometer-range (for example metals, metal oxides, or nitrides) which give the glass dichroic optical properties. Also the blue appearance of some automobile windshields is caused by dichroism.\n",
"Privacy films reduce visibility through the glass. Privacy film ... |
why primary education is disproportionately a female institution? | That's a pretty tough question to answer, and I think it also depends on the country you live in.
A 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.
Or 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.
It's really more of an open-ended discussion than a cut-and-dry answer. | [
"The foremost factor limiting female education is poverty. Economic poverty plays a key role when it comes to coping with direct costs such as tuition fees, cost of textbooks, uniforms, transportation and other expenses. Wherever, especially in families with many children, these costs exceed the income of the famil... |
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? | 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.
There'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."
Most of the evidence points towards both decay and new associations being responsible for forgetting.
If you spontaneously recall the memory later, then that would be a pretty strong indication that it was an issue with recall and not encoding. | [
"Memory is not a perfect processor, and is affected by many factors. The ways by which information is encoded, stored, and retrieved can all be corrupted. The amount of attention given new stimuli can diminish the amount of information that becomes encoded for storage. Also, the storage process can become corrupted... |
How often do neutrinos interact with us? What happens when they do? | > How often do neutrinos interact with us?
A 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.
So 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.
> What happens when they do?
[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.
> And, lastly, is the Sun the only source from which the Earth gets neutrinos?
Two 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).
There'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.
------
And 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. | [
"The Kamiokande II detection, which at 12 neutrinos had the largest sample population, showed the neutrinos arriving in two distinct pulses. The first pulse started at 07:35:35 and comprised 9 neutrinos, all of which arrived over a period of 1.915 seconds. A second pulse of three neutrinos arrived between 9.219 and... |
Was Joseph Smith sincere? | 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.
1. 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_).
2. 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.
3. 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.
| [
"My instinct is to attribute a sincerity to Joseph Smith. And yet at the same time, as an evangelical Christian, I do not believe that the members of the godhead really appeared to him and told him that he should start on a mission of, among other things, denouncing the kinds of things that I believe as a Presbyter... |
Why do cochlear implants not produce normal hearing, and what would they need to do so? | 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.
[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.
The 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.
[Wikipedia](_URL_1_)
edit: [This is an article about cochlear implants, place theory, and channels](_URL_2_) | [
"Cochlear implants improve outcomes in people with hearing loss in either one or both ears. They work by artificial stimulation of the cochlear nerve by providing an electric impulse substitution for the firing of hair cells. They are expensive, and require programming along with extensive training for effectivenes... |
If time stops completely at the event horizon, how can black holes grow? | 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.
In 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.
Since 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.
Black 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. | [
"For a black hole to physically exist as a solution to Einstein's equation, it must form an event horizon in finite time relative to outside observers. This requires an accurate theory of black hole formation, of which several have been proposed. In 2007, Shuan Nan Zhang of Tsinghua University proposed a model in w... |
in philosophy, what are epistemology and metaphysics? | True ELI5:
Epistemology = "How do I know shit? What does it mean to know shit?"
Metaphysics = "What is this shit? What is shit? What is?" | [
"Epistemology – philosophy of knowledge. It is the study of knowledge and justified belief. It questions what knowledge is and how it can be acquired, and the extent to which knowledge pertinent to any given subject or entity can be acquired. Much of the debate in this field has focused on the philosophical analysi... |
how can we smell spring? | 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). | [
"Avuş spring - According to information of local people, the name of the spring is from word of \"ovuc\" (the handful), it was so called as the shape it is similar to the handful. In the Turkic languages, \"avuş/avuj\" means \"vaccine, alum\". And this show the existence of the same material in the content of the w... |
what's happening inside of a plasma ball? | 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.
The 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. | [
"A similar explanation involves a similar phenomenon in plasma physics. A free-floating plasma orb, created when surface electricity (e.g., from a capacitor) is discharged into a solution. However, most plasma ball experiments are conducted using high voltage capacitors, microwave oscillators, or microwave ovens, n... |
how could pixar produce toy story back in 1995? | The whole reason for the concept of Toy Story is because of the limitations of the technology at the time.
Somewhere 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."
Later, 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.
But toys are by far the easiest thing to animate and render, so they did that first. | [
"\"Toy Story\" (1995) was the first computer-animated feature film in Pixar's debut contract with Disney. In 2015, movie writer Julia Zorthian said in TIME, \"Children and adults flocked to theaters when Toy Story opened, making it the highest-selling film for three weeks in a row. As the first full-length, 3D comp... |
how do download and upload speeds actually work,(i.e how do they limit the speed of download through your cables) | 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.
Basically, 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. | [
"BULLET::::- Files are downloaded in multiple streams, which under certain conditions can accelerate download speeds by up to eight times, depending on the bandwidth of the Internet connections and the speed at which the server sends files. At present, an option to increase or decrease the downloading speed is not ... |
how come the zimbabwe dollar inflated so fast? how do people survive in a country with such hyperinflation? | 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.
The 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.
In 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.
How 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.
In 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.
As 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.
The 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.
The 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).
Eventually, 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.
It'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. | [
"The economy of Zimbabwe shrank significantly after 2000, resulting in a desperate situation for the country – widespread poverty and a 95% unemployment rate. Zimbabwe's participation from 1998 to 2002 in the war in the Democratic Republic of the Congo set the stage for this deterioration by draining the country of... |
in ww2 movies and rl videos some soldiers salute and some use nazi salute. why is that? | Nazi salute (with straight right hand) was mandatory for civilians but optional for military. Soldiers mostly used traditional salute. | [
"During filming, Galland, who was acting as a German technical adviser, took exception to a scene where Kesselring is shown giving the Nazi salute, rather than the standard military salute. Journalist Leonard Mosley witnessed Galland spoiling the shooting and having to be escorted off the set. Galland subsequently ... |
What happens when I take a USB drive out without ejecting? | 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.
The 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.
The 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. | [
"In this scenario, the transfer is done directly from the old (source) machine's hard drive. The drive can be connected externally (USB adapter / enclosure), or internally, as a secondary drive. This scenario works even for old computers that are unable to boot, as long as the data is intact.\n",
"BULLET::::- Dri... |
Panzer tanks: "first-class visual and command facilities"? | 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.
But 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_).
So in sum, not only did early war panzers possess better optics and radios, they were a more ergonomic design than their contemporaries.
*Sources*
Forczyk, Robert. *Tank Warfare on the Eastern Front*. Barnsley: Pen & Sword Military, 2014.
Zaloga, Steve. *Panzer IV Vs Char B1 Bis: France 1940*. Oxford: Osprey Pub, 2011. | [
"\"Panzer Command\" is a tactical level simulation of armored combat, recreating the battles that raged across the steppes of the Soviet Union during the middle years of World War II. Each of two players commands the 40 to 60 company-sized units of a German armored division or Soviet tank corps, maneuvering forces ... |
why do competitions require you to answer a ridiculous question when you enter? | 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. | [
"A challenge is a request made to the holder of a competitive title for a match between champion and challenger, the winner of which will acquire or retain the title. In some cases the champion has the right to refuse a challenge; in others, this results in forfeiting the title. The challenge system derives from du... |
what is treasury yields and why does it cause the market to slide? | First all the quick answers:
Treasuries 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.
Now the why:
Treasuries 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.
That 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.
So when treasury yields rise, all other investment income rates also have to rise, and that means most investment prices fall. | [
"Since the yield of virtually any fixed-income instrument is affected by changes in the shape of the Treasury curve, it is not surprising that traders examine future and past performance in the light of changes to this curve.\n",
"Another common way for accounting for treasury stock is the par value method. In th... |
why does urinating feel different when you are sick? | For a multitude of reasons, among them:
+ 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
+ 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
+ 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 | [
"Urinary symptoms include urinary frequency, urgency, incontinence and retention. Again, because of the retention of urine, urinary tract infections are frequent. Urinary retention can lead to bladder diverticula, stones, reflux nephropathy.\n",
"Functional incontinence is a form of urinary incontinence in which ... |
why did sega drop out of the video game console business? | 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... | [
"From 1993 to early 1996, although Sega's revenue declined as part of an industry-wide slowdown, the company retained control of 38% of the U.S. video game market (compared to Nintendo's 30% and Sony's 24%). 800,000 PlayStation units were sold in the U.S. by the end of 1995, compared to 400,000 Saturn units. In par... |
Why do some metals turn bright red and white when they are melting? Why don't they just turn to liquid like mercury does? | 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.
This is called the [Draper point](_URL_0_). It happens at 525 Celsius. | [
"Some metals appear coloured (Cu, Cs, Au), have low densities (e.g. Be, Al) or very high melting points, are liquids at or near room temperature, are brittle (e.g. Os, Bi), not easily machined (e.g. Ti, Re), or are noble (hard to oxidise) or have nonmetallic structures (Mn and Ga are structurally analogous to, resp... |
How do Colloids work? | 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.
Think 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. | [
"The term \"colloid\" is used primarily to describe a broad range of solid-liquid (and/or liquid-liquid) mixtures, all of which contain distinct solid (and/or liquid) particles which are dispersed to various degrees in a liquid medium. The term is specific to the size of the individual particles, which are larger t... |
why should someone never refreeze something that has been unfrozen ? | 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.
This 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.
When 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." | [
"People sometimes defrost frozen foods at room temperature because of time constraints or ignorance; such foods should be promptly consumed after cooking or discarded and never be refrozen or refrigerated since pathogens are not killed by the freezing process.\n",
"Items deemed resellable are displayed for purcha... |
the ending of the sopranos | Here's a very detailed analysis:
_URL_0_
I personally think you have to pick one of two narratives:
1. 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.
or
2. 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.
| [
"\"The Bald Soprano\" appears to have been written as a continuous loop. The final scene contains stage instructions to start the performance over from the very beginning, with the Martin couple substituted for the Smith couple and vice versa. However, this decision was only added in after the show's hundredth perf... |
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? | 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?
In 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.
For 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.
Where 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.
Here 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?
Now, 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.
To 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.
So, 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. | [
"But passwords are typically not safe to use as keys for standalone security systems (e.g., encryption systems) that expose data to enable offline password guessing by an attacker. Passphrases are theoretically stronger, and so should make a better choice in these cases. First, they usually are (and always should b... |
What sort of judicial system did the Confederacy have during the Civil War? | 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.
State 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.
If you do end up researching the Confederate judiciary, please send me your findings! My interest has definitely been piqued. | [
"Confederate district courts were authorized by Article III, Section 1, of the Confederate Constitution, and President Davis appointed judges within the individual states of the Confederate States of America. In many cases, the same US Federal District Judges were appointed as Confederate States District Judges. Co... |
stock dividends | 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. | [
"In 1982 the dividend yield on the S&P 500 Index reached 6.7%. Over the following 16 years, the dividend yield declined to just a percentage value of 1.4% during 1998, because stock prices increased faster than dividend payments from earnings, and public company earnings increased slower than stock prices. During t... |
what determines whether a pro sports team is named after a city (dallas cowboys), or after a state (minnesota vikings)? | That’s completely up to the team owner(s), they can name it whatever they like.
Look 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. | [
"Some other sports teams gained their names from being in Minnesota before relocating. The Los Angeles Lakers get their name from once being based in Minneapolis, the City of Lakes. The Dallas Stars also derived their present name from their tenure as a Minnesota team, the Minnesota North Stars.\n",
"The game did... |
If I travel fast enough to red or blue shift radio waves, what would happen to the sound coming from a radio program? | 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.
Modulation 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!
You could almost say that traveling at a certain rate is the same thing as single-sideband FM modulation! | [
"BULLET::::- Some digitally-tuned FM radios are unable to tune using 50 kHz or even 100 kHz increments. Therefore, when traveling abroad, stations that broadcast on certain frequencies using such increments may not be heard clearly. This problem will not affect reception on an analog-tuned radio.\n",
"Very high f... |
What makes an explosive effective at different jobs? | 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.
C4 has extremely high brisance for antipersonnel and anti-armour, and gunpowder has low brisance for launching objects. | [
"To determine the suitability of an explosive substance for a particular use, its physical properties must first be known. The usefulness of an explosive can only be appreciated when the properties and the factors affecting them are fully understood. Some of the more important characteristics are listed below:\n",
... |
why do wombat's poop cubes? | 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? | [
"In wombats and marsupial moles, the pouch opens backward or down. Backwards facing pouches would not work well in kangaroos or opossums as their young would readily fall out. Similarly, forward-facing pouches would not work well for wombats and marsupial moles as they both dig extensively underground. Their pouche... |
how does the army/military wash clothes while deployed? | At the laundry. Deployed at base you still sleep in a bed/cot. Deployed in the field, you don't wash | [
"Many parts of the world still use washboards for washing clothes. Clothes are soaked in hot soapy water in a washtub or sink, then squeezed and rubbed against the ridged surface of the washboard to force the cleansing fluid through the cloth to carry away dirt. Washboards may also be used for washing in a river, w... |
in movie scenes depicting large crowds or groups, do the extras usually have scripted dialogue or do they ad-lib? | 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.
Source: I work in the film industry. | [
"Virtually all dialogue in the film is improvised. Actors were given outlines indicating where scenes would begin and end and character information necessary to avoid contradictions, but everything else came from the actors. As often as possible, the first take was used in the film, to capture natural reactions. \n... |
Do animals get tired of eating the same food day after day? | 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. | [
"It is common for animals (even those like hummingbirds that have high energy needs) to forage for food until satiated, and then spend most of their time doing nothing, or at least nothing in particular. They seek to \"satisfice\" their needs rather than obtaining an optimal diet or habitat. Even diurnal animals, w... |
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? | I don't care how anyone ELI5 this question but please do it using an analogy with candy or something. | [
"In the second term of 2007, euro as a reserve currency had reached a record level of 25.6% (a +0.8% increase from the year before) – at the expense of the US dollar, which dropped to 64.8% (a drop of 1.3% from the year before). By the end of 2007, shares of euro increased to 26.4% as the dollar slumped to its lowe... |
the modern "war on women" | 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.
The 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.
The 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.
In 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.
There is nothing wrong with women or men staying home or being chaste, but when the government is supporting this, it creates an oppressive environment.
| [
"The modern Women Against War movement was created by women in the Capital Region and surrounding communities. The vision statement of the modern-day movement is that war is not the answer and that women can help to develop alternatives to violence.\n",
"This timeline of women in warfare and the military (1900–45... |
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? | No.
You'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.
But 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.
If you just had a motor directly turning a generator, you would *still* lose energy. That's like asking if a crank can turn itself...
*Those numbers are just made up off the top of my head and wildly inaccurate. | [
"From the 1930s to late 1940s, Nelco Industries made a three-wheeled battery powered vehicle. Steering was by means of a tiller connected to the front wheel. The tiller also provided speed control. Forward or reverse by a separate control. The 24 volt electric motor could act as a generator to recharge the battery ... |
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? | 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.
I'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.
But 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? | [
"After their discovery of the New World in the 15th century, European states began trying to establish New World colonies. England, the Dutch Republic, France, Portugal, and Spain were the most active.\n",
"During the early modern period, some European nation-states and their agents adopted policies of colonialis... |
What was life like in Spain in the early 70's? | I don't have any sources at hand but I will tell you what I remember from my Spanish High School history lessons:
Franco 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.
When 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'.
It 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. | [
"The nightlife in Spain is very attractive to both tourists and locals. Spain is known to have some of the best nightlife in the world. Big cities such as Madrid and Barcelona are favorites amongst the large and popular discothèques. For instance, Madrid is known as the number one party city for clubs such as Pacha... |
What will I hear if I talk while breaking the sound barrier? | 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 | [
"The acoustical science of noise barrier design is based upon treating an airway or railway as a line source. The theory is based upon blockage of sound ray travel toward a particular receptor; however, diffraction of sound must be addressed. Sound waves bend (downward) when they pass an edge, such as the apex of a... |
Is it possible that society actually needs wars as an engine for progress in technology? What does history say about this? | 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.
This 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.
The 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?
Any 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?
Such 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.
Just 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.
In 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. | [
"On the supply side, it has been observed that wars sometimes have the effect of accelerating progress of technology to such an extent that an economy is greatly strengthened after the war, especially if it has avoided the war-related destruction. This was the case, for example, with the United States in World War ... |
What do you end up with if you tear something apart at a 'molecular level'? | Well first, that sounds like garbledeygook ad copy, so I wouldn't put much stock in the scientific value of that TV spot.
As 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.
Could 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. | [
"Although all damage at the atomic level manifests as broken atomic bonds, the manifestation of damage at the macroscopic level depends on the material, and can include cracks and deformation, as well as structural weakening that is not visible.\n",
"All physical damage begins on the atomic level, with the shifti... |
why does money exist? | Because it's inconvenient to have to trade water buffalo for skittles.
| [
"BULLET::::- \"\"...but money has become by convention a sort of representative of demand; and this is why it has the name 'money' (nomisma)-because it exists not by nature but by law (nomos) and it is in our power to change it and make it useless.\"\" Aristotle, Nicomachean Ethics [1133b 1].\n",
"BULLET::::- To ... |
how do intangible currencies like bitcoin and dogecoin have value? | People will accept it for goods and services. Therefore it has value. | [
"5. While most of these currencies are restricted to a small geographic area or a country, through the Internet electronic forms of complementary currency can be used to stimulate transactions on a global basis. In China, Tencent's QQ coins are a virtual form of currency that has gained wide circulation. QQ coins c... |
Evolution Debate | [Nothing in Biology Makes Sense Except in the Light of Evolution - Theodosius Dobzhansky](_URL_0_) | [
"One of the main sources of confusion and ambiguity in the creation–evolution debate is the definition of \"evolution\" itself. In the context of biology, evolution is genetic changes in populations of organisms over successive generations. The word also has a number of different meanings in different fields, from ... |
in u.s., "math". in u.k., "maths". why? | Linguists discuss the math vs. maths wording: _URL_0_ | [
"The mathematicians Edward Frenkel and Hung-Hsi Wu wrote in 2013 that the mathematical education in the United States is in \"deep crisis\" caused by the way math is currently taught in schools. Both agree that math textbooks, which are widely adopted across the states, already create \"mediocre de facto national s... |
if number of offspring in mammals roughly correlates with mammary glands, why are twins not the predominant birth in humans? | 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. | [
"Most mammals, including humans, have an XY sex-determination system: the Y chromosome carries factors responsible for triggering male development. In the absence of a Y chromosome, the fetus will undergo female development. This is because of the presence of the sex-determining region of the Y chromosome, also kno... |
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? | It depended on the country. I can shed some light on the American and Soviet methods of disarmament.
When 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)
In 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. | [
"During World War II, losses of major items of equipment were substantial in many battles all throughout the war, with no exception on the Eastern Front. Due to the expense of producing such equipment as replacements, many armies made an effort to recover and re-use enemy equipment that fell into their hands , appl... |
why is a fan higher pitched when on higher speeds? | 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. | [
"The speed of rotation (specified in revolutions per minute, RPM) together with the static pressure determine the airflow for a given fan. Where noise is an issue, larger, slower-turning fans are quieter than smaller, faster fans that can move the same airflow. Fan noise has been found to be roughly proportional to... |
why during medical trials both control and subject group are told they are receiving experimental drug instead both being told they receive placebo? | 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."
Telling 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. | [
"If a drug is being tested, the control group will frequently be given a placebo. This is done as a double blind test, as neither the healthcare professional nor the patient know if they are receiving the drug under test or a placebo, and don't find out which substance was administered until after the experiment is... |
- why do most honour killings involve murdering the victim? why not kill the rapist instead? | 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.
It is fucked up. | [
"Honour killing is an act of murder, in which a person is killed for his or her actual or perceived immoral behavior. Such \"immoral behavior\" may take the form of alleged marital infidelity, refusal to submit to an arranged marriage, demanding a divorce, perceived flirtatious behaviour and being raped. Suspicion ... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.