Split (2)

train · 226k rows

question stringlengths 3 301	answer stringlengths 9 26.1k	context list
why can't all the countries pool their resources and eradicate poverty/hunger/war across the globe?	The big 3:greed, mistrust of other countries and just not caring about other countries citizens. Contries have enought problems in their own country so why would they try to search for them outside of it.	[ "However, there are many who believe that the world has more than enough resources to sustain its population. Instead, these theorists point to unequal distribution of resources and under- or unutilized arable land as the cause for malnutrition problems. For example, Amartya Sen advocates that, \"no matter how a fa...
How does the level of political polarization in the U.S. today compare to the years just prior to the Civil War?	This is probably more of a question for /r/Ask_Politics, but I can give you a basic reason why this is so difficult for anyone to answer. The attempt to compare political polarization to pre-Civil War polarization is very, very difficult not only because of the shifting parties, but because of the alterations in cultu...	[ "Despite various claims that argue American society is more polarized today than leading up to the U.S. Civil War, numerous scholars explain that much evidence shows there is a relatively stable public opinion on the majority of sociopolitical issues. Where the most polarization exists, rather, is in the \"hot topi...
Crooks and Criminals in the Union/Confederate Armies?	Of course there were bad guys in both armies. Some were just scoundrels and others were actually terrible people. Fold3, which is a digitized primary records site, mentions Pvt. William H. Cole from the 109th New York Volunteer Infantry, who was court martialed for rape. His defense wasn't that he didn't do it, but th...	[ "The Lowrie gang, as it became known, resorted to crime and conducting personal feuds, committing robberies and murders against white Robeson County residents and skirmishing with the Confederate Home Guard. They grew bolder as the war turned against the Confederates. In December 1864, the Lowrie gang killed James ...
Ross Perot’s 1992 presidential campaign garnered 19% of the popular vote, the best third-party showing since Teddy Roosevelt’s run in 1912. Who were his supporters and why was he so successful?	Great question! One of the initial promises of George H. W. Bush was to not raise taxes. It was his oft-repeated promise-- "read my lips: no new taxes. I'm not going to do it." In fact, it was so often repeated by Bush that it formed the foundation for his portrayal on Saturday Night Live by Dana Carvey (who revised ...	[ "In the 1992 election, he received 18.9% of the popular vote, about 19,741,065 votes, but no electoral college votes, making him the most successful third-party presidential candidate in terms of the popular vote since Theodore Roosevelt in the 1912 election. Unlike Perot, however, some other third party candidates...
Why do so many things in nature manifest themselves in the form of waves? E.g photons, sound, electrons	i'll phrase it very vaguely: whenever you have some negative feedback to an action you'll likely end up with waves. the equation for the force of a spring in relation to the elongation Δx is F = -kΔx, so if you extend a spring it will tend back to its equilibrium position. if you have any kind of potential with a mini...	[ "Through the work of Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr, and many others, current scientific theory holds that all particles exhibit a wave nature and vice versa. This phenomenon has been verified not only for elementary particles, but also for compound particles like atoms an...
how my girlfriend can be colder than me all the time until she is under a blanket/asleep at which point she becomes a human space heater?	because science. remember that your body senses the rate of heat exchange, not the temperature. She feels "warm" to you because she is losing her own heat really fast, and therefore it's going into your body rapidly. Your senses register that rapid absorption of heat as if it's "hot". In reality she's just getting c...	[ "Depending upon the watch system, two, or even three people may end up sharing the same bunk. The term comes from the military slang use of the term \"rack\" for a bed or bunk. With more than one crew member assigned to a rack, it is possible that a crew member returning from a duty shift will lie down on a rack im...
Antibiotics vs toughing it out	This isn't my area of expertise, but there are at least three things happening here: * Bacteria can become resistant to that antibiotic. This is bad, so it's an argument to use antibiotics only when necessary. Even worse is that bacteria can trade plasmids more rapidly and become resistant to many types of antibiotics...	[ "Antibiotic resistance is a naturally occurring phenomenon throughout the entire world due to the overuse and/or inappropriate use of the substance. However, its usage is supported primarily because of its effectiveness in the treatment and prevention of diseases, as well as its role as growth promoters. Antibiotic...
how can a company come out with an all in one gaming system that uses emulators to play roms from nes and snes and sega systems and not face copyright laws?	Emulators are perfectly legal. It's the ROMs that can't be distributed without permission. Either the system you're talking about doesn't include any ROMs, they paid a crapload of license fees, or it is indeed infringing on copyrights.	[ "BULLET::::- Emulators allow software exclusive to one system to be used on another. For example, a PlayStation 2 exclusive video game could be played on a PC using an emulator. This is especially useful when the original system is difficult to obtain, or incompatible with modern equipment (e.g. old video game cons...
how does a debit card number end up across the world in just a day or two after the number gets stolen?	The people who stole your number most likely will have either sold the number, or sent the details off to people who work with them in other countries, in this case, Australia. Then, they have blank cards with magnetic strips on them waiting to be loaded with all your information so they can go to the bank with them.	[ "When a credit card is lost or stolen, it may be used for illegal purchases until the holder notifies the issuing bank and the bank puts a block on the account. Most banks have free 24-hour telephone numbers to encourage prompt reporting. Still, it is possible for a thief to make unauthorized purchases on a card be...
The average lifespan used to much lower than it is now, did people still have mid life crisis back then in their teenage years?	Life expectancy is calculated by computing average age of death, so given that about half of children died before their teenage years the averages are skewered downward and don't tell us much at all about how long people lived at all. Post-childhood human life expectancy is was stable at around 70, before climbing up...	[ "In 1960, the average life expectancy of the world population was 50 years. Forty-five years later, in 2004, life expectancy had improved by over 30% to 67 years. Improvements in health care and the reduction in child mortality have led to a jump forward in middle-income countries, where life expectancy is now over...
why do unresponsive network operations freeze your computer?	Because of cheaper (or lazy) programming. Every behavior could have been controlled, unless you go into extremely demanding math or graphics. However, the proper management of cases that should never occur is expensive and not very productive. The case of unresponsive network also has an additional problem when o...	[ "Deep Freeze can also protect a computer from harmful malware, since it automatically deletes (or rather, no longer \"sees\") downloaded files when the computer is restarted. The advantage of using Deep Freeze is that it uses very few system resources, and thus does not slow down computer performance greatly. The d...
why is it so hard for antibiotics to stop bacterial sepsis?	Sepsis is when chemicals released while fighting an infection trigger inflammation throughout the body and as a consequence the failure of multiple organs. Antibiotics are certainly useful but sepsis is an indication that a tough fight is already being lost, so giving antibiotics isn't any guarantee to save the patient...	[ "Though effective, antibiotics are not recommended for prevention of TD in most situations because of the risk of allergy or adverse reactions to the antibiotics, and because intake of preventive antibiotics may decrease effectiveness of such drugs should a serious infection develop subsequently. Antibiotics can al...
what makes a person need glasses? in addition, what is the difference between short and long sightedness?	It has something to do with your eyes or retinas not being ideally shaped. This causes less than clear vision. Short sightedness just means you can see things close to you but have a problem focusing on far away objects. Long sightedness is the opposite of this.	[ "Glasses are beneficial to those who have severe nearsightedness, whereas individuals with retinal degeneration need training for the visually impaired, which is usually more beneficial when this is addressed at a young age. Younger patients start out having unimpaired vision, but it starts to deteriorate at a youn...
How is information stored and transferred from one point to another when conducting a phone call?	Compression of speech signals is very complicated, and is actually more art than science. This is primarily because the final metric is whether or not people like it. It is also an active area of research, and have gotten down to at least [8.3 kbps (PDF page 6)](_URL_2_) kbps. Which is basically nothing compared to the...	[ "Mobile phones are commonly used to collect location data. While the phone is turned on, the geographical location of a mobile phone can be determined easily (whether it is being used or not) using a technique known as multilateration to calculate the differences in time for a signal to travel from the mobile phone...
What is the history behind socialization of public roads in Western society? Were there ever any privately owned public roads, and if so what was the result?	Roads and trails have a ubiquity and long history in English legal thought as something more related to a freedom than to a consumer good, the way modern drivers see them. But toll bridges and tunnels were quite commonly built and owned by private individuals, in the same manner as ferries were. In the US, there were...	[ "Outside cities, roads were dirt or gravel; mud in the winter and dust in the summer. Early organizers cited Europe where road construction and maintenance was supported by national and local governments. In its early years, the main goal of the movement was education for road building in rural areas between cities...
why do i get lumps on my head instead of bruises?	When you get a bump on your leg, the blood that forms a bruise can 'spread' out and leak inwards. On your head the blood only has one way to go: up. That's why you get a big bump instead of a deep bruise.	[ "A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasate into the surrounding interstitial tissues. Most bruises are not very deep under the skin so that the bleeding causes a visible discoloration. ...
can someone explain why haiku is 5 7 5 i just want to know?	Haiku originated as the opening stanza of a kind of poetry called [Renga](_URL_0_). Renga is made by two or more people improvising lines of poetry in turn, alternating between lines of 5-7-5 and 7-7. Honestly, I haven't been able to find a reason why they choose those particular counts, but I suspect it's just a ple...	[ "Haiku are a short, 3-line verse form, which have achieved significant global popularity, and the haiku form has been adapted from Japanese into other languages. Typical of the haiku form is the metrical pattern of 3 lines with a distribution of 5, 7, and 5 \"on\" (also known as morae) within those lines. Other fea...
What color is the grass at night?	At night, the grass is still green, but you perceive it as black. There's a difference between the physical color of an object and the perceived color by an observer. The physical color is a property of the object and the materials it is made of. Every substance has its own response to the various wavelengths of visi...	[ "The sky can turn a multitude of colors such as red, orange, pink and yellow (especially near sunset or sunrise) and black at night. Scattering effects also partially polarize light from the sky, most pronounced at an angle 90° from the sun.\n", "There is also large expense of green grasses especially during the ...
Do all orbitals have infinite ranges with only specific regions of high probability of finding an electron? And if so, does it mean that technically an atom is infinite in size?	All bound-state wavefunctions for a Coulomb potential have the property that there is no distance beyond which the radial wavefunction is always zero. So they technically extend to infinity. But the “size” of the atom is usually defined in terms of an RMS charge radius, or something similar, which has a finite value. ...	[ "Only electrons in \"s\" orbitals demonstrate non-zero probability because their 3D spherical shape incorporates the volume taken up by the nucleus. However, the \"p\", \"d\", and other electrons may influence the \"s\" electron density through a screening effect.\n", "If these two electrons are correlated, then ...
William Wallace- the welshman?	The answers /u/Searocksandtrees linked will provide a more comprehensive account of William Wallace than I am going to here. The short version is that we don't know a lot about his early life, but what we do know is broadly supportive of him being a member of the lesser Scottish gentry. I've vaguely encountered the who...	[ "One result of Wallace's early travels is a modern controversy about his nationality. Since Wallace was born in Monmouthshire, some sources have considered him to be Welsh. However, some historians have questioned this because neither of his parents was Welsh, his family only briefly lived in Monmouthshire, the Wel...
Gravity question that stumped my grandpa...	The only reason items have a terminal velocity is that their acceleration due to gravity is balanced by their deceleration due to the air resistance they feel. No air, no resistance, no terminal velocity. So the bullet would continuously accelerate till it hit the ground.	[ "This episode documents how gravity has a profound effect across the universe, and Cox seeks out a non-space zero-gravity experience to highlight his point. From the formation of galaxies and stars to the patterns of uplift and erosion seen on Earth, gravity is centrally important. Examples are given, such as the t...
how does long chain of atoms (polymer) form a 2d surface ?	The question doesn't make sense because you haven't provided: Which polymer How large of a surface What you qualify as "2 dimensional" Under what conditions What context are you trying to ask about?	[ "BULLET::::- Transfer to polymer. Chain transfer may take place with an already existing polymer chain, especially under conditions in which much polymer is present. This often occurs at the end of a radical polymerization when almost all monomer has been consumed. Branched polymers are formed as monomer adds to th...
How long did recombination (photon decoupling) actually take?	~10,000 years, pretty much the same 10,000 years everywhere. The probability that a photon didn't get absorbed any more increased continuously from "nearly 0%" to "nearly 100%" over this timescale. I don't find a nice plot showing this now. /u/Rumetheus: This is quite long on human timescales.	[ "Prior to recombination, photons were not able to freely travel through the universe, as they constantly scattered off the free electrons and protons. This scattering causes a loss of information, and \"there is therefore a photon barrier at a redshift\" near that of recombination that prevents us from using photon...
Did historians of the time know that Pompeii and Herculaneum existed prior to it's discovery or had it been forgotten from history until it's unearthing?	A contemporary account of these events by Pliny the Younger still exists, and an on-line version can be found [here](_URL_0_).	[ "In 1748, he began prospecting the nearby ancient city of Pompeii, (which had previously been believed to be Stabiae), noted for the fact that it remained virtually unchanged, with expressions of surprise still on the inhabitants who remained there intact, buried by the sudden eruption of Vesuvius. This discovery r...
chelsea manning and why she is being let off lightly for what i understand is treason?	[Article 2 section 2 of the US Constitution](_URL_0_), he(President of the United States)shall have power to grant reprieves and pardons for offenses against the United States, except in cases of impeachment. Barack Obama was elected to a second term by the Electoral College, confirmed by Congress on Jan 6, 2013 for a...	[ "Chelsea Elizabeth Manning (born Bradley Edward Manning, December 17, 1987) is an American activist and whistleblower. She is a former United States Army soldier who was convicted by court-martial in July 2013 of violations of the Espionage Act and other offenses, after disclosing to WikiLeaks nearly 750,000 classi...
how can finland afford to give every citizen 800 euros a month?	The US spends $13,500 per capita on social programs. Any first-world country could easily afford to given its citizens a 800 EUR/mo basic income. However, in the case of Finland (as I understand it, at least) the basic income is intended to replace most other public benefits. It's sort of like how the US started givi...	[ "Finland's income is generated by the approximately 1.8 million private sector workers, who make an average 25.1 euro per hour (before the median 60% tax wedge) in 2007. According to a 2003 report, residents worked on average around 10 years for the same employer and around 5 different jobs over a lifetime. 62 perc...
The American Revolutions is often thought of as America vs. England. What was the sentiment about the rebellion in Scotland, Ireland and Wales?	Follow-up question: what was the state of the Scottish Parliament at the time, and did it have any interaction with or input on the decisions made by the English Parliament & Crown?	[ "BULLET::::- American Revolution – The American Revolution was the political upheaval during the last half of the 18th century in which the Thirteen Colonies in North America joined together to break free from the British Empire, combining to become the United States of America.\n", "The American Revolution had i...
what are the positives of free trade agreements?	Proponents of free trade argue that it helps reduce poverty by creating jobs and getting money circulating in an area. Throughout the late 20th Century a lot of countries, particularly across Africa and Asia, began to accept free trade and saw a decline in poverty almost immediately. A lot of the time companies were ...	[ "Obama has urged Congress to ratify a 12-nation free trade pact called the Trans-Pacific Partnership. In theory, free trade enables economies to focus on those products where they have comparative advantage, making both economies better off. While trade maximizes the overall outcome, specific groups are helped or h...
when i'm sick, why does my body try to keep vomiting even when my stomach is empty?	It's your body's attempt at flushing the virus out. It may seem ineffective to you, but it does improve your body's internal condition against the viral war.	[ "While the vomit response is commonly assumed to be a chemical reaction between the two foods, the reaction may also occur due simply to the large amount of food and drink ingested within a short period. Dietitian Heather Boline observes that the human stomach can only hold around two cups, saying \"Too much food o...
Why weren't we able to detect extrasolar planets until fairly recently?	Because it requires camera's capable of detecting extraordinarily minute changes in a star's brightness and location/gravitational wobble I would imagine I'm surprised googling this yielded pretty much nothing.	[ "Most confirmed extrasolar planets have been found using space-based telescopes (as of 01/2015). Many of the detection methods can work more effectively with space-based telescopes that avoid atmospheric haze and turbulence. COROT (2007-2012) and Kepler were space missions dedicated to searching for extrasolar plan...
What is the oldest record of human homosexuality in our history?	What is your definition of homosexuality? is it same sex relations? because that is not exclusively a homosexual practice. The word itself was only coined in 1869 ("Homosexual Studies and Politics in the 19th Century: Karl Maria Kertbeny". Journal of Homosexuality) so can you trace homosexuality back further than the ...	[ "The earliest records of homosexuality and same-sex relations in China date from the Shang dynasty era ( 16th to 11th century BCE). The term \"luan feng\" () was used to describe homosexuality. No records of lesbian relations exist, however. In this time, homosexuality was largely viewed with indifference and usual...
what stopped the internet during its inception to turn into how cable tv was?	Firstly it is important to know that originally the internet was created by the US government, called DARPA net as a way for scientists to communicate during the cold war. the biggest strength of DARPA net was that if one node was destroyed, then information could still flow to the rest of the network, useful in a nucl...	[ "The first cable system started to operate in the early 1960s in Monterrey, as a CATV service (an antenna at the top of the Loma Larga, which could get TV signals from Laredo, Texas and the Rio Grande Valley). Most of the other major cities didn't develop cable systems until the late 1980s, due to government censor...
if no one is above the law, why should the president be allowed to pardon individuals that broke the law?	It is a check on the system both for moral reasons (maybe sometimes mercy is justified) and practical ones (it empowers the president to directly protect executive officials from political prosecutions, rather than just indirectly protect them via appointments.)	[ "The Supreme Court has not ruled on whether a president can pardon someone for state or local crimes, dicta in Ex parte Garland stated that the pardon power extends to all offences known to the law . Experts disagree as to whether a president can pardon himself, but pardons cannot apply to cases of impeachment. The...
Were free blacks during slavery better off than 'free' blacks during segregation?	In a word, no. First, remember that there was a great variation of standards of living depending on income, and location. Solomon Northrup's father was a property owner and he was relatively well educated. He likely was much better off than the average Negro at the time. The movie depicted an idyllic scene, but few, i...	[ "Since the 16th century, thanks to a government approved program called \"manumisión\", the black slaves were allowed to pay for their freedom with their own savings. Therefore, a larger number of free blacks were dedicated to the manual labors in the fields than in the cities and some of them were also able to bec...
how does rocket fuel work in space? wouldn't it just float around unable to reach the fuel pump?	Some spacecraft use [Ullage motors](_URL_0_). These are small rockets that fire just before the main engine to force the fuel to settle at the bottom of the tank.	[ "A low-propellant space drive has long been a goal for space exploration, since the propellant is dead weight that must be lifted and accelerated with the ship all the way from launch until the moment it is used (see Tsiolkovsky rocket equation). Gravity assists, solar sails, and beam-powered propulsion from a spac...
Taking account of its diverging and unifying factors during its civilization gestation, to what extent is it sensible to refer to early East Asia (up to Circa 1200) as a collective region ?	Is this a homework question? It says in our [rules](_URL_0_): Our users aren't here to do your homework for you, but they might be willing to help. Remember: AskHistorians helps those who help themselves. Don't just give us your essay/assignment topic and ask us for ideas. Do some research of your own, then come to us ...	[ "The Sinologist John Didier made an extensive investigation of what he calls the \"interactive Eurasian world, c. 9000–500 BC,\" that is, the mutual ties between ancient East Asia, South Asia, and the Middle-East, including Persia and Babylon. These exchanges, he argues, shaped the foundations and early evolution o...
if the majority of people in the us are sickened by the acts of their gov't why hasn't there been any change?	There is change, we have elections every two years (four for president) Every two years we vote on the entire house of representatives (half of congress, the legislative-lawmaking branch of government), and 1/3 of the senate (the other half of congress). In general, people keep electing the same people as long as the...	[ "Distrust in government has become a prevalent issue recently. In the United States for example, Americans have been polled every year about their confidence in their country’s institutions (e.g. the Supreme Court, Congress, the Presidency, and the health-care establishment), and there has been a reported collapse ...
How did the Ancient Persians dress?	Do you mean the Sasanians or Achaemenids? Common people or nobility? Clergy?	[ "Sasanian dress (Middle Persian: \"ǰāmag\" or \"paymōg\"), represented by the Persians, was \"broadly similar\" to dresses worn by other Iranian peoples. It was especially appropriate and applicable for horse riding. Most extant primary sources for the study of Sasanian dress are forms of visual art, rock reliefs i...
what's the difference between the department of justice (doj) and the fbi?	The DOJ is a cabinet-level agency which is responsible for enforcing US federal law. The FBI is an agency which operates under that (along with many other agencies and departments). A full breakdown is here: _URL_0_	[ "The Department of Justice administers several federal law enforcement agencies including the Federal Bureau of Investigation (FBI), the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), and the Drug Enforcement Administration (DEA). The department is responsible for investigating instances of financial fr...
Who really did invent aviation, Santos-Dumont or the Wright brothers?	No single person or persons invented aviation, rather it was the result of many years of research by a large number of people. The Wright Brothers are generally agreed upon as being the first to invent a flying machine that had all the elements required to be practical, but they expanded upon the experiences of many o...	[ "Much controversy has surrounded these claims. It is most widely held today that the Wright Brothers were the first to fly successfully. Brazil regards Santos-Dumont as the first successful aviator because the Wright Flyer took off from a rail and, after 1903, used a catapult. An editorial in the influential \"Jane...
why do some nfl teams draft a hyped qb from college only to not start him in the following season?	Because he isn't ready. Their hype is (usually) from their college performance, but college performance =/= professional performance. So teams will often draft someone very good, but sit them for a season or 2 to let them get ready.	[ "These quarterbacks have started at least one game for the National Football League (NFL)'s Los Angeles Chargers or its predecessor, the San Diego Chargers. They are listed in order of the date of each player's first start at quarterback for the team.\n", "31 quarterbacks have started for the National Football Le...
what is the definition of a moral absolute?	Metaethicist here! Moral absolutism the view that certain actions are absolutely, categorically right or wrong regardless of any circumstance - even intentions or consequences. So for example, if I thought murder was absolutely wrong then it would be wrong in any form - capital punishment, euthanasia... etc. The exi...	[ "God is the absolute. The absolute is inadequately conceptualized as substance, power, person – although Watson found \"personality\" more fitting, though still inadequate – or super rational. The. absolute is the identity of subject and object, the repository of universal reason itself, the very rationality that i...
Heating ceramics in a microwave	I would think the chemists and physicists would be able to test this - and are probably more qualified to do so than a random biochemist on Reddit.... Anyhow, The heat transferred to the water does indeed come by increasing the movement of the water molecules - but the rotation isn't the only way in which you can tran...	[ "In the 1970s, glass-ceramic cooktops started to appear. Glass-ceramic has very low thermal conductivity, a coefficient of thermal expansion of practically zero, but lets infrared radiation pass very well. Electrical heating coils or infrared halogen lamps are used as heating elements. Because of its physical chara...
How did the Etichonids establish themselves?	Beyond the VIIth century, we know little of most of Frankish aristocratic family and that includes Peppinids and Arnulfians. A great deal of hypothesis comes down to their genealogical origins and relations to other families during and after the Carolingian takeover, which does let out a lot of non-Austrasian lineages....	[ "The Etichonids were an important noble family, probably of Frankish, Burgundian or Visigothic origin, who ruled the Duchy of Alsace in the Early Middle Ages (7th–10th centuries). The dynasty is named for Eticho (also known as Aldarich) who ruled from 662 to 690.\n", "The Hasmonean Dynasty was founded by a resolu...
why do some street lights buzz?	For the same reason that some fluorescent lights buzz. They contain a circuit to generate a high voltage (because that is needed to pull electrons off the gas in the bulb and ionize it). That high voltage circuit is oscillating, and the rapid current changes cause rapid magnetic field changes. The leads to [magnetos...	[ "Light clutter refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles (including those that they may be intended to illuminate), and potentially cause accidents. Clutter is particularly noticeable on roads where the street lights are badly designed, or where bri...
Discuss the accuracy of Allied WW2 Europe bombing missions.	Someone else can give some more detail, especially regarding other forces, but actually finding the target to bomb made the accuracy of the bombsight almost moot. The United States Strategic Bombing Survey found that, on average, only 20% of the bombs intended for strategic targets actually fell within the target are...	[ "\"Europe Ablaze\" covers the period 1939 to 1945 and contains three scenarios that depict strategic bombings in Europe during World War II. The scenarios are based on Battle of Britain, Royal Air Force night bombings of summer 1943, and Allied bombings of Germany in 1945.\n", "BULLET::::- Overy, Richard. \"The B...
how do surgeons know what can be cut and what can not? can every part of your body 'heal' like a cut?	How do they know? From years of medical school, which teaches them the result of many many years of medical research, what's been tried, what failed, what worked.	[ "Surgery can be done in case a peripheral nerve has become cut or otherwise divided. This is called peripheral nerve reconstruction. The injured nerve is identified and exposed so that normal nerve tissue can be examined above and below the level of injury, usually with magnification, using either loupes or an oper...
why are many train rides so bumpy even though the rails are apparently straight?	Remember the train is traveling on steel wheels, not air-filled rubber tires, so any variation in the tracks is more likely to be felt. The rails may not be as straight as you think. Trains that travel on very straight rails (notable, high-speed trains) do indeed have very smooth rides.	[ "The trains have been criticised for providing insufficient space for luggage and bicycles. Also, because the units are designed to tilt, the carriages have a tapered profile that narrows towards roof level, resulting in a less spacious interior than the conventional carriages they replaced.\n", "The design of a ...
What is the origin of America's "Car Dealership" system, which seems to be giving Tesla such a problem these days?	hi all! This post references current events, but don't let that distract you: per this subreddit's 20-year rule, do confine all responses to events/conditions prior to 1995 only. Thanks!	[ "Tesla Motors has rejected the dealership sales model based on the idea that dealerships do not properly explain the advantages of their cars, and they could not rely on third party dealerships to handle their sales. However, in the United States, direct manufacturer auto sales are prohibited in almost every state ...
Why don't particle accelerators used magnets that can become superconducting using Liquid Nitrogen?	As far as I know (this is for NMR magnets, but the same will likely apply to accelerators), the main reason is that most high temperature superconductors are brittle ceramic materials, so it is very difficult to make coils out of them. Especially considering the large stresses that act on the coils when the magnet is b...	[ "In 1986, the discovery of high temperature superconductors by Georg Bednorz and Karl Müller energized the field, raising the possibility of magnets that could be cooled by liquid nitrogen instead of the more difficult to work with helium.\n", "HTS require only liquid nitrogen, not liquid helium, to cool to super...
question about hearing loss	Imagine a rubber band. Push on it really hard for a short amount of time. It will bend back to the original shape, unless that push is hard enough to break it. Now push on it hard for a long time. It will start to lose its strength, and succumb to breaking easier. Inside your ear are a bunch of proverbial rubber ba...	[ "Hearing loss may be caused by a number of factors including heredity, congenital conditions, age-related (presbycusis) and acquired factors like noise-induced hearing loss, ototoxic chemicals and drugs, infections, and physical trauma.\n", "Hearing loss has multiple causes, including ageing, genetics, perinatal ...
how did scientists measure the age of the universe if spacetime is relative?	Measuring the age of the universe doesn't really involve relativity because we're not comparing reference frames from different observers. If have 2 observers in 2 different reference frames, they might not agree on the age of the universe, but that's not really useful information for us. The main way we've measured t...	[ "More recent measurements from WMAP and the Planck spacecraft lead to an estimate of the age of the universe of 13.80 billion years with only 0.3 percent uncertainty (based on the standard Lambda-CDM model), and modern age measurements for globular clusters and other objects are currently smaller than this value (w...
How did the mass arrival of Catholic immigrants from Europe influence northeastern America in the nineteenth century?	well, for one thing, there was the Philadelphia Nativist Riots: _URL_0_	[ "A wave of European Catholics immigrated to the United States between 1840 and 1920, including Germans, Italians, Poles, Slovaks, and Croatians, and many Franciscan friars came from their home countries to minister to them in their own language.\n", "During the mid 19th century, a wave of \"old\" immigrants from ...
I've heard it mentioned a few times that NATO chose the 5.56 bullet because it more likely maim than kill outright, and thus wear down the enemy through attrition as they try to help wounded soldiers. Is this true? If so, won't this be against conventions of war?	Been asked before here - your question specially is the second question comment down. It’s all a good read. _URL_0_	[ "Compared to larger calibers, proponents of the 5.56×45mm NATO round contend that animal studies of the wounding effects of the 5.56×45mm NATO round versus the 7.62×39mm have found that the 5.56×45mm NATO round is more damaging, due to the post-impact behavior of the 5.56 mm projectile resulting in greater cavitati...
Where did our traditional childhood fables come from?	The following summary of definitions of folktale and fairytale from my draft Introduction to Folklore (to be e-published in September), may be of use; feel free to ask questions: Folktales – or Märchen, using the German, technical term – are longer stories with more than one episode. They are restricted, in theory at ...	[ "The fable is very old and may predate Aesop since it seems to have been used by the 7th century BCE poet Archilochos. In Europe it was for a long time restricted to Greek sources but it was one of those that also travelled eastwards into Central Asia from about the 8th century CE. Papyrus fragments of the fable fr...
Does scent falloff according to the inverse square law?	At low Reynolds number this is almost right, except the odor intensity drops off as 1/r, not 1/r^(2). Typically we are in a high Reynolds number regime though, so the odor is distributed by turbulent convective flows that can't be described by a simple equation. Reynolds number describes whether inertia or viscosity d...	[ "Graham's law of effusion (also called Graham's law of diffusion) was formulated by Scottish physical chemist Thomas Graham in 1848. Graham found experimentally that the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles. This formula can be written as:\n", "Phanto...
Were there any significant pagan rebellions/uprisings in Medieval Egpyt?	I've never come across any suggestion that there were any pagans left at the time of the Arab conquests, so as far as I'm aware there was no "cleansing of them via Muslim forces." They had already been "cleansed" by Christians over the preceding 300 years.	[ "In 1127 the first pagan rebellions began to take place. These were due to both the large tribute imposed by Poland as well as a plague that descended on Pomerania and which was blamed on Christianity. The rebellions were largely instigated by the old pagan priests, who had not come to terms with their new circumst...
why do some downloads not show file size and / or etas?	When you make an HTTP connection, there are a bunch of pieces of metadata that are sent before the data. One of those is Content-Length, which tells your client how long the data portion is going to be. If you don't see a file size in a download, it means the server didn't send a Content-Length header, so your client...	[ "An ETag is an opaque identifier assigned by a Web server to a specific version of a resource found at a URL. If the resource representation at that URL ever changes, a new and different ETag is assigned. Used in this manner, ETags are similar to fingerprints and can quickly be compared to determine whether two rep...
how are gemstones identified/classified, if they come in multiple colors, like a green garnet?	Historically gemstones were identified primarily by their physical properties (color, hardness, etc.) and so names have changed over time (the stone called "smaragdus", which is the origin of "emerald", by the ancient Greeks is not necessarily the stone we cal emerald today, and was probably applied to a variety of gre...	[ "Gemstones are classified into different \"groups\", \"species\", and \"varieties\". For example, ruby is the red variety of the species corundum, while any other color of corundum is considered sapphire. Other examples are the emerald (green), aquamarine (blue), red beryl (red), goshenite (colorless), heliodor (ye...
Can an animal be recreated by DNA only?	No. At the very least, and this is unlikely, we'd need the egg of a donor animal. In the fertilization process, a number of epigenetic factors take over that govern the development of the organism, and that can't be reproduced using DNA alone. I have no idea what kind of technology these aliens have, but what we've got...	[ "This work has been criticised on grounds that once an animal is extinct, it cannot re-exist. This is contrary to Heck's view, which is that while genes of an extinct animal still exist in extant descendants, the animal could still be recreated.\n", "The DNA sequences used in the construction of recombinant DNA m...
why does speed affect the turning radius of a car?	it doesn't. turning radius is a mechanical angle of front wheel and distance between front wheel and rear wheel. due to speed, you may not be able to achieve that turning radius at speed because the mass of the car exceeds capabilities of friction of the rubber tires on ground. that's more of a skid pad result,...	[ "When turning, any object is subject to a certain amount of centrifugal force, directed away from the center around which the object is moving. As speed increases, the amount of force applied to the object also increases. As a result, standard narrow vehicles with a narrow wheel base, can only take turns up to rela...
how does shotgun genome sequencing work?	A rifle shoots a single bullet in a straight line. A shotgun shoots a bunch of metal balls out in a sort of random pattern. So say the sequence is ABCDEFG (obviously not a real sequence, but it's easy to track). * The shotgun approach would shoot randomly and cut the data so it's AB and then separately CDEFG. * On...	[ "Shotgun sequencing is a sequencing method designed for analysis of DNA sequences longer than 1000 base pairs, up to and including entire chromosomes. It is named by analogy with the rapidly expanding, quasi-random firing pattern of a shotgun. Since gel electrophoresis sequencing can only be used for fairly short s...
What is the universe (in layman's terms)?	Everything that can, in principle, be measured. To expand: --- okay so let's start with what measurements we can make and then what measurements we can in principle make. We can make a lot of measurements here on earth, so we know the earth is part of the universe. From the earth, we are quickly limited to almos...	[ "According to Takahashi, the universe that we live in is the source of \"banshou\" (all beings) and \"banbutsu\" (all things), and follows various principles, starting with the principle of samsara (cycle). The macrocosm is controlled by one large \"cosmic consciousness\" that harmonizes the universe. This consciou...
Can humans actually die from grief? What causes such an extreme turn in the body that can make this happen?	There is a fairly uncommon type of Cardiomyopathy known as "Broken Heart Syndrome" also called Takotsubo after a type of octopus trap that can be brought on by stress, grief and emotional loss. And it can mimic a heart attack and can be lethal. Here. [](_URL_0_)	[ "Grief is the deep sorrow usually caused by someone's death. It has now become a normal human reaction to a loss of a loved one. It is not uncommon for someone to be in sadness. Many have to deal with coping with grief.\n", "Divorce and death are two negative events that spoil the need to belong. Divorce causes d...
if all humanity was wiped out what would happen to the other species which inhabit earth?	Well, there was a documentary on History Channel called [Life After People](_URL_0_). I'm pretty sure there was another on NatGeo that said life would basically flourish if humans just disappeared.	[ "Human extinction can be prevented by improving the physical barrier or increasing the mean distance between people and the potential extinction event. For example, pandemics are controlled by placing exposed people in quarantine and evacuating healthy people away. The human lineage of genus \"Homo\" has reduced fr...
Does general relativity predict a different volume and radius of earth than the naive euclidian calculation based on the observed circumference? How about black holes?	The Schwarzschild radius, Rs, of the Earth is around 9 mm. One consequence of this is that the circumference of a circle of radius R drawn around the Earth is the same as the circumference of a Euclidean circle of radius R - Rs. So general relativity causes the circumference of the Earth to be 2πRs = 55.7 mm less th...	[ "On the largest scale, scale relativity offers a new perspective on the issue of redshift quantization. With a reasoning similar to the one which allows to predict probability peaks for the velocity of planets, this can be generalized to larger intergalactic scales. Nottale writes:\n", "Unless the universe modele...
Is it possible for people to survive without a symbiotic relationship with good bacteria in our stomach?	For the first question, no, or not very well. More [research](_URL_0_) is coming out that we really need our gut bacteria. It helps us to absorb nutrients, and helps us defend against bad bacteria-you're not supposed to feed honey to infants under 2 years old because they may not have sufficient gut bacteria built up...	[ "Due to the high acidity of the stomach, most microorganisms cannot survive there. The main bacterial inhabitants of the stomach include: \"Streptococcus\", \"Staphylococcus\", \"Lactobacillus\", \"Peptostreptococcus\", and types of yeast. \"Helicobacter pylori\" is a gram-negative spiral bacterium that establishes...
How is piezoelectricity turned into energy we use?	It really isn't an energy source, although it does have some interesting uses. With piezoelectricity, applying a mechanical stress to the crystal can generate a voltage, and also vice versa. So it is a useful technique for transforming energy, and for doing some other things. One of the common devices using this...	[ "Piezotronics effect is using the piezoelectric potential (piezopotential) created in materials with piezoelectricity as a “gate” voltage to tune/control the charge carrier transport properties for fabricating new devices. Neil A Downie showed how simple it was to build simple demonstrations on a macro-scale using ...
5: how is it safe for chiropractors to crack people necks?	The answer is very simple: it’s not! Chiropractors can and do end up killing people by doing that. Here’s a recent example: _URL_0_	[ "A 2012 systematic review concluded that no accurate assessment of risk-benefit exists for cervical manipulation. A 2010 systematic review stated that there is no good evidence to assume that neck manipulation is an effective treatment for any medical condition and suggested a precautionary principle in healthcare ...
Do people tend to seem more attractive in groups?	_URL_0_ It's called the Cheerleader Effect :)	[ "In short, the more physically attractive an individual is, the more likely they are to experience decreased levels of sociometric popularity but increased levels of perceived popularity for engaging in relationally aggressive activities.\n", "Additionally, people who are of above average attractiveness are assum...
If iron loses it's magnetism around 800 degrees C, how can the earth's core, at ~6000 degrees C, be magnetic?	[Dynamo Theory](_URL_0_). Quote: _"In this dynamo mechanism, fluid motion in the Earth's outer core moves conducting material (liquid iron) across an already existing, weak magnetic field and generates an electric current. The electric current, in turn, produces a magnetic field that also interacts with the fluid moti...	[ "The iron-rich core region of the Earth is divided into a radius solid inner core and a radius liquid outer core. The rotation of the Earth creates convective eddies in the outer core region that cause it to function as a dynamo. This generates a magnetosphere about the Earth that deflects particles from the solar ...
Could the break up of Yugoslavia have been conducted peacefully, and was there credible attempts to do so ?	It is doubtful that violence could have been completely avoided, and certainly not in a situation of very tense national relations. However, I do believe that it could have been significantly reduced, in many areas or in total. As both tunaghost and Sprinkless already pointed out, areas of violence are very well corre...	[ "Some observers opined that the break up of the Yugoslav state violated the principles of post-Cold War system, enshrined in the Organization for Security and Co-operation in Europe (CSCE/OSCE) and the Treaty of Paris of 1990. Both stipulated that inter-state borders in Europe should not be changed. Some observers,...
what should i know about saudi arabia given recent events? what would it mean if the world held them responsible for khashoggi’s death?	Another reason needed to start a war?	[ "For 18 days, Saudi Arabia denied Khashoggi had died in the consulate, before indicating a team of Saudi agents had overstepped their orders to capture him when a struggle ensued leading to his death. Turkey said it believes the killing was premeditated and approved by the Saudi government, and sought extradition o...
In the early 1870s, how long would a letter from the East Coast of the U.S. to the West take to be delivered?	Telegraphic costs were far higher. I asked a similar question about [the expense of sending telegraphs during the Civil War](_URL_0_). In 1870, it would have cost 6 cents to send a letter. In that same year, it would have cost $1 to send a 10-word telegram between New York City and Chicago. Costs would have been much g...	[ "Butterfield's Overland Mail Company held the U.S. Mail contract from September 16, 1858, on a six-year contract. The first stage going east left San Francisco at ten minutes past midnight on September 14, 1858. The mail from San Francisco reached St. Louis in twenty-four days, eighteen hours, and twenty-six minute...
how come one of the most common typing errors is to type a word twice in a row without noticing?	I read your title twice and then once again just to make sure that you hadn't typed one of the the words twice as a trick!	[ "Common \"errors\" may also be quite characteristic of a person, and there is an entire taxonomy of errors, such as this person's most common \"substitutions\", \"reversals\", \"drop-outs\", \"double-strikes\", \"adjacent letter hits\", \"homonyms\", hold-length-errors (for a shift key held down too short or too lo...
why do you have to go through courses in college even if you have the knowledge required to get the degree in question?	Receiving the bachelor's degree (which I assume you have in mind) is not just about how much you know. You must have the ability to critically discuss the topic in a scholarly way--not just to repeat what others have said, but find errors in their work or synthesize the works of different scholars. Partly you show th...	[ "Generally, A-Levels or CAPE examinations are required to enter the nation's universities. One may also qualify after having earned a 3-year diploma from an accredited post-secondary college. The word college usually denotes institutions which do not grant at least a bachelor's degree. Universities are typically th...
is europe (the eu) basically the same as america in terms of setup?	There are similarities, but in some ways it's more like the USA was under the articles of the confederation than the USA under its current constitution. The biggest difference is that the members of the EU are still in theory sovereign states. They have their own representation in the UN, they have their own independe...	[ "The European Union was created in 1948, post World War II to unite European communities. Some of the institutions that make up the European Union are the European Parliament, European Commission, and the European Council. While the United States is not a part of the European Union, the two work together and collab...
Why wouldn't gravity counteract the heat death of the universe?	> Why wouldn't gravity counteract the heat death of the universe? There are two possibilities, that the universe expands forever or that it collapses. We are reasonably confident that it will expand forever. If the maximum entropy of the universe is fixed, and the universe can only increase in entropy, then eventuall...	[ "The idea of heat death of the universe derives from discussion of the application of the first two laws of thermodynamics to universal processes. Specifically, in 1851, William Thomson outlined the view, as based on recent experiments on the dynamical theory of heat: \"heat is not a substance, but a dynamical form...
Is obesity not always due to excessive food consumption and/or poor dietary habits and failure to exercise?	At the very very least, there are thyroid imbalances. No research needed. A deficit in thyroid hormone (hypothyroidism) will cause weight gain and lethargy among other things. No, you cannot blame most of obeisity on this. But yes, there are legitimate hormonal reasons for weight gain/inability to loose weight.	[ "BULLET::::- There is no evidence that obesity is related to slower resting metabolism. Resting metabolic rate does not vary much between people. Weight gain and loss are directly attributable to diet and activity. Overweight people tend to underestimate the amount of food they eat, and underweight people tend to o...
Fear vs anger: in the human body, what is the physiological / hormonal difference between fear and anger?	A fairly technical paper on the subject (abstract only, link to full paper below): In contrast to a general model of stress, a functional model suggests that emotions may regulate stress responses in specific adaptive ways. The current study examined whether anger and fear during a challenging stress task (Trier S...	[ "Negative emotions, including anger and fear, can be seen as the evolution of human adaptation to survival in life-threatening situations. For example, anger shows the sign of attack, fear shows the sign of escape. These emotional reactions interconnect with our mind and body. These negative emotions are influenced...
how do telescope long exposures work, considering earth rotation and movement?	Equatorial mounts are used, which are devices that once aligned with the north or south celestial pole (depending on location), will move with the rotation of the Earth so things don’t appear to move. When people say they did a 24 hour exposure, it is often not a single 24 hour exposure, but rather a bunch of smaller ...	[ "Accurate telescope pointing and tracking is critical for obtaining good astronomical images and astrophotographs. However, because the Earth rotates, the sky appears to be in a constant state of motion relative to the Earth. Although this movement appears to be relatively slow when viewed with the naked eye, with ...
What is the evolutionary benefit of a citrus fruit growing as a ball of "slices"?	I believe this is largely due to the way the ovary develops early on, but as for what the advantage would be, I'd guess that the small membranes between each section serve as a small added barrier to protect against fungus and bacteria spread. Not an expert here but thought I'd try to answer your question.	[ "The juice vesicles aka citrus kernels (in aggregate, pulp) of a citrus fruit are the membranous content of the fruit's endocarp. All fruits from the Citranae subtribe, subfamily Aurantioideae, and family Rutaceae have juice vesicles. The vesicles contain the juice of the fruit and appear shiny and baglike. Vesicle...
what causes joint pain when people are ill?	When you are ill, your lymphatic system swells up with toxins. This build up causes pain in the areas where your lymphatic system is located ie: behind ears, jaw and joints	[ "The most common symptoms are diarrhea, abdominal pain, weight loss, and joint pains. The joint pains may be due to migratory non-deforming arthritis, which may occur many years before any digestive tract symptoms develop; they tend to involve the large joints but can occur in any pattern and tend not to damage the...
why is there not a number you can text similar to 911 for times where calling isn't an option at all (kidnapping, house invasion, etc.)?	It is often, and it will be everywhere. _URL_0_ The short answer to "why not yet" is that most emergency response centers are not yet setup to handle texts. The carriers in the middle are all set to handle it when the response centers get their shit together.	[ "Because of the design of U.S. central office (phone) switches, it was not practical to use the British emergency number 999 (as was briefly considered). What was up to that time unassigned area code 911 was chosen instead. The \"1\" as the second digit was key; it told the switching equipment that this was not a r...
what happens to our brains when we become frozen with fear?	Fight or flight response. The amygdala controls that.	[ "Studies suggest that specific areas of the brain are known to either elicit (or inhibit in the case of lesions) freezing behavior in subjects. The regions include the basolateral amygdala and the hippocampus.\n", "It has been shown that parts of the brain are involved in freezing behavior and that neurotransmitt...
What factors cause/increase the chance of rain?	Sure, there's a bunch of factors which produce rain: I'll start with three. 1. Humidity / dewpoint. Air itself can hold a certain amount of air. You can inject more and more water into air and it'll absorb it. However, once you reach 100% saturation, then it'll precipitate out, in the form of liquid water — rain! 2. ...	[ "Furthermore, climate change has apparently led to a reduction in the level of rainfall. For example, in Sana'a the average rainfall has declined by one sixth from 240mm (average 1932–1968) to 200mm (1969–1982) and 180mm (1983–2000).\n", "Altered precipitation patterns are also anticipated (both annually and seas...
Will useless traits always disappear given enough time?	A useless trait isn't one that will disappear. It's a hindering trait that will disappear eventually. If the trait has no purpose, but also doesn't hinder us in any way, it'll stick around in the population.	[ "In some cases, it is difficult to tell whether a trait has been lost and then re-evolved convergently, or whether a gene has simply been switched off and then re-enabled later. Such a re-emerged trait is called an atavism. From a mathematical standpoint, an unused gene (selectively neutral) has a steadily decreasi...
Is there a depression gene?	It’s currently thought that there likely is but it has yet to be definitively proven. Genome wide association studies (GWAS) compare the genes of people with depression. You can then look for similarities between these people and then differences between them and people without depression. This allows you to see some g...	[ "Genetic factors involved in depression have been difficult to identify. Historically, candidate gene studies have been a major focus of study. However, as the number of genes reduces the likelihood of choosing a correct candidate gene, Type I errors (false positives) are highly likely. Candidate genes studies freq...
How were the basic principles of science developed, and why are they held to be true? Is it possible to test them empirically? If so, have they been?	I'd recommend posting this at /r/philosophyofscience to get some perspectives from philosophers.	[ "A number of 20th-century philosophers maintained that logical models of pure science do not apply to actual scientific practice. It was the publication of Thomas Kuhn's \"The Structure of Scientific Revolutions\" in 1962, however, which fully opened the study of science to new disciplines by suggesting that the ev...
Why does the speed of light always move ahead of you at "c", even if you go 99% of the speed of "c"?	If you go really fast, space and time are distorted, since time will be moving at a slower rate, and space will be a shorter distance, the speed of light (measured using the now altered time and space) will go C faster than you. This is a bit of a simplification, naturally. But should help visualize what's going on.	[ "The fact that light is predicted to always travel at speed \"c\" would be incompatible with Galilean relativity if Maxwell's equations were assumed to hold in any inertial frame (reference frame with constant velocity), because the Galilean transformations predict the speed to decrease (or increase) in the referen...
eye damage from looking at the sun.	“it’s particularly dangerous because of the anatomy of our eyes, Joel Schuman, chair of ophthalmology at NYU Langone Health, explains. When light enters our eyes, the lens focuses light to the retina, located in the back of the eye. We see thanks to the retina’s chemical sensors picking up on the presence of light and ...	[ "Looking directly at the photosphere of the Sun (the bright disk of the Sun itself), even for just a few seconds, can cause permanent damage to the retina of the eye, because of the intense visible and invisible radiation that the photosphere emits. This damage can result in impairment of vision, up to and includin...
If the US civil war wasn't fought well by European standards why didn't the two sides import expert help?	> If the Europeans were so much better, why didn't the Americans import some experts The famous Italian general Giuseppe Garibaldi was offered a commission as Major General in the Union army. He turned it down because (depending on who you talked to) he wanted to be the Commander-in-Chief of the entire Union army, ...	[ "Although they remained out of the war, the European powers, especially France and Britain, factored into the American Civil War in various ways. European leaders saw the division of the United States as having the potential to eliminate, or at least greatly weaken, a growing rival. They looked for ways to exploit ...
Why did English Historians often Anglicise Roman names with a -y suffix? Livius to Livy, Plinius to Pliny, Pompeius to Pompey etc.	[Anglicization has always been about either preserving the meaning or the pronunciation of the word in a way where a native speaker of English can read and/or understand it,](_URL_0_) and Worcester's explanation as to how proper names are Anglicized feature the desire to make pronunciation easier as the names are not e...	[ "Likewise, some entirely Old English names explicitly point to Roman structures, usually using Latin loan-words, or to the presence of Brittonic-speakers. Names like \"Wickham\" clearly denoted the kind of Roman settlement known in Latin as a \"vicus\", and others end in elements denoting Roman features, such as \"...
how does see through advertising on city busses work?	It's a [screen/grid](_URL_0_). When you're inside you see threw the holes and there's just a solid color to not distract your eyes. On the outside, so the bright colors of the ad command attention over the small holes that don't distract your eyes.	[ "Transit advertising is typically advertising placed on anything which moves, such as buses, subway advertising, truckside, food trucks, and taxis, but also includes fixed static and electronic advertising at train and bus stations and platforms. Airport advertising, which helps businesses address an audience while...
Why can't cameras focus on the background and foreground at the same time?	You should check out Lytro. It's a special camera that was developed fairly recently that takes in an entire field of view without a specific focus. You can in later and manually adjust the focus of pictures taken with it. If you do check it out it's some fairly CSI type stuff. The camera is fairly low res right now bu...	[ "A special case occurs when the camera is moved during exposure while keeping it pointed at a moving target, so as to hold its projection on the recording medium steady. The stationary environment (usually mainly background, but possibly also some foreground) then is subjected to ICM and appears streaked in the fin...
why did hitler start wars on so many fronts? why did he have to break the non-aggression pact with the ussr? how could he not have thought of the consequences?	Two words: Crazy Genius. All his successes were due to his willingness to take big risks on things no one else would dare to do. This paid off for him many times. Invading Russia was not one of those times. Simultaneously the source of his greatest strength and his greatest weakness.	[ "Hitler believed that after the invasion of the Soviet Union, the war in the East was to destroy Bolshevism, as well as aiming to ruin the Great Russian Empire, and a war for German expansion and economic exploitation.\n", "Hitler had been considering war with the Soviet Union since July 1940. Regarding a potenti...
tough one...can anyone tell me about stagflation and the idea of unemployment v inflation? (elim5)	Alright, so these are kind of separate but related issues. I'll talk about the unemployment/inflation trade-off first. Basically the idea is this: there is something called the "natural rate" of unemployment. This rate is greater than zero. The reason for that is that you want there to be some unemployment; unemploym...	[ "In economics, stagflation, or recession-inflation, is a situation in which the inflation rate is high, the economic growth rate slows, and unemployment remains steadily high. It presents a dilemma for economic policy, since actions intended to lower inflation may exacerbate unemployment, and vice versa. \n", "Up...
I have so many Questions about the World's Fair !!	The World's Fair was conceptualized in its modern sense by Prince Albert around 1850. It was held in Hyde Park's Crystal Palace, and was perceived initially as a way to show off the results of industrialization within Europe, but also exposure of colonized worlds (in an admittedly very appropriated sense) for Westerner...	[ "World's Fair Nano's mission of putting forth a non-BIE effort to bring the World's Fair back to the United States is considered rather important since there has not been a full-scale World's Fair in the United States in the past three decades. The most recent World's Fair in the United States was the 1984 Louisian...
what's the difference between using mouthwash and brushing your teeth? are there any benefits to doing both / neither?	What causes our teeth to decay is actually the excrement of bacteria. As we eat, food particles stick to our teeth and bacteria start eating on them. These bacteria poop acid on our teeth and that wears down the enamel. If you only use mouthwash, it would kill the bacteria, but leave most of the food particles and acid...	[ "Mouthwashes come in a variety of compositions, many claiming to kill bacteria that make up plaque or to freshen breath. In their basic form, they are usually recommended for use after brushing but some manufacturers recommend pre-brush rinsing. Dental research has recommended that mouthwash should be used as an ai...
(Statistics) What is the difference between selection bias and healthy user bias?	It's probably best to think of Healthy user bias as a type of selection bias that is introduced from the participant's side, and that the researcher's will have to try to control for. As a contrived example - If a study recruits participants by placing flyers in parks and gyms, that would be gross selection bias becau...	[ "Self-selection bias causes problems for research about programs or products. In particular, self-selection affects evaluation of whether or not a given program has some effect, and complicates interpretation of market research.\n", "BULLET::::- Selection Bias: Selection bias occurs when some units have a differi...

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