question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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how did we as humans collectively decide on the location of the international date line? | It didn't.
The date line is the opposite side of the globe to the Prime Meridian (roughly).
There were multiple Prime Meridians throughout history, typlically countries with large a large navy or merchant shipping fleet would have their own. Eventually they all lost out to the current PM. | [
"However, the conventional International Date Line is a relatively recent geographic and political construct whose exact location has moved from time to time depending on the needs of different interested parties. While it is well-understood why the conventional date line is located in the Pacific Ocean, there are ... |
Were does the inertia of a playground swing come from? | Swings with children pumping their legs to increase their peak height have actually quite complicated physics that many people confuse with the simpler case of a pendulum with constant peak height and constant total energy.
Where does the extra energy come from to increase the child's total energy (gravitational potential energy plus kinetic energy)? The energy ultimately comes from the child's muscles. How does energy get transferred from the muscles to the swing? The same way that muscles always create kinetic energy: by pushing off something or pulling towards something. If a child were floating in an empty vacuum with nothing to push, pull, or throw, she could not increase her linear kinetic energy, because of conservation of energy. So what is the child pushing off of or pulling against? The only thing that the child is connected to which is not moving with her is the bar to which the swing chains are attached on the top. Therefore, the child's pumping of her legs must effectively allow her to push off from or pull towards the bar. And this is indeed what happens.
But it gets more complicated. The chains of the swing are typically connected to the bar so that force can only be transmitted between bar and chain in the radial direction and not in the tangential direction (this is, after all, what allows the swing to swing freely in the angular direction). Also, chains can only be pulled and not pushed. The only option to exert a force on the bar is therefore to pull the chain radially away from the bar. How can a child gain net momentum tangentially if she can only pull radially away from the bar?
The key is that a force can be redirected by an intervening agent (e.g. a ramp can redirect a downwards force into a sideways force). The intervening agent in this case is the child's body itself and how it is stuck by friction in the chair of the swing. When pumping, the child is effectively pulling radially away against the bar through the chains and diverting this radial force to a tangential force using her body and its connection to the swing seat and chains. Therefore, a force that is radially away from the bar becomes a tangential force that is able to angularly accelerate the child and increase her peak height.
If the seat of the swing were large, flat and frictionless, and the child was careful not to hold or touch the chains, then there would be no way to divert the radial pull on the chains to a forwards push. The child would not able to increase her peak height. She would just slide around on the chair (or fall off) when she pumped her legs, but would not get it swinging.
> Do swing sets work in vacuum and with perfectly friction less bearings?
Yes. The child is not pushing off the air and is not directly pushing tangentially off the bar through the chains. She is pulling radially away from the bar. | [
"A familiar experience of both parametric and driven oscillation is playing on a swing. Rocking back and forth pumps the swing as a driven harmonic oscillator, but once moving, the swing can also be parametrically driven by alternately standing and squatting at key points in the swing arc. This changes moment of in... |
Why do serrations help knives and saws cut? | Serrated blades focus the pressure onto many smaller points of contact, and those contact points are at a higher angle, both of which works better to cut some surfaces or materials. It isn't quite as smooth of a cut, though. | [
"BULLET::::- Serrated blade knives have a wavy, scalloped or saw-like blade. Serrations help when cutting things that are hard on the outside and soft on the inside (such as bread or tomatoes); the saw-like action breaks the surface more easily than anything except the very sharpest smooth blade. They are also part... |
How were Medieval churches and cathedrals financed? | Selling indulgences *per se* was not the main way cathedrals were financed in the Middle Ages, though they certainly had an important role in constructing St. Peter’s. The main source of financing of cathedrals came from the local communities, lay and clerical, that commissioned them. Remember that the rise of the great cathedrals from the late 12th century onward coincided with the rise of towns and the development of a new urban class—people who neither worked, prayed, nor fought, as the traditional medieval concept of the “three orders of society” had it, but people who made *money* as merchants, bankers, and tradesmen. Cathedral building was a communal undertaking paid for by the contributions of the prosperous people of towns. Cathedrals, in fact, were signs of civic pride. Across much of Europe, towns competed to see who could build the most elaborate cathedral, which usually meant the tallest. (This same mentality--is it phallocentric??--still lives as modern cities compete to see who has the tallest building: New York’s new World Trade Center? Chicago’s old Sears Tower? And the winner is . . . Dubai’s Burj Khalifa.) You can see this civic pride at Chartres Cathedral where various trades commissioned stained glass windows depicting their trade. Such sponsorship was both a mark of secular pride and pious devotion to God.
Even those townsfolk who weren’t rich could gain grace by making donations to cathedral building. Yes, these donations won indulgences, but in the early days of cathedral building—the late 12th-14th centuries—selling indulgences had not yet reached the abusive levels that it would in the later Middle Ages. In fact, very famously there are reports of upper- and lower-class people hauling stones in wagons as a pious act to help rebuild Chartres Cathedral in the late 12th century.
One other side of this: where cathedrals were attached to monasteries, these could use their vast landed wealth to help finance their building, as could the always powerful and wealthy bishops whose church the cathedral was. Most dioceses also demanded a small annual fee from everyone living in the diocese (which was a collection of dozens of parishes) for the upkeep of the cathedral, the “mother church” of the diocese. Using income left as pious offerings at a cathedral’s shrines housing powerful relics of saints could also subsidize building. Remember that cathedrals were the most impressive physical achievement of the Middle Ages; remember also that it typically took several generations from start to finish. (St. John the Divine in NYC was started in 1892; it’s still not finished.)
As for ordinary churches, by which I assume you mean the typical parish church, financing came overwhelmingly from the income from land, since about 90% of medieval people lived not in cities but the countryside. Specifically I mean from tithes. All parishioners were obliged to give annually 10% of their income (mostly agricultural products) to their parish church. Parishioners were also obliged for the upkeep of the nave of the church, that area where they stood at Mass. Their priest was responsible for the upkeep of the church’s chancel, where the main altar was. In towns, parishes were established in neighborhoods. There, folks were also obliged to tithe, but many of them were approaching what we would call “middle class,” so they had disposable wealth that they could invest in pious building. The wealthiest of them could even build private chapels attached to their parish church.
TL,DR: Indulgences as we understand the term at the start of the 16th-century Reformation played a secondary role in building cathedrals and churches.
One good source: Robert A. Scott, *The Gothic Enterprise: A Guide to Understanding the Medieval Cathedral* (2005). For parish churches a good summary is Richard Kieckhefer’s chapter “The Impact of Architecture” in *A People’s History of Christianity: Medieval Christianity* ed. Daniel E. Bornstein (2010).
Edit: One more thought. One reason it could take generations to build a cathedral is that sometimes the building stalled when the money ran out due to whatever reasons. Sometimes it took concerted effort to raise more money. When angry townsfolk burned down Laon Cathedral in 1122, the monks there took its relics on the road around the region to collection donations to rebuild it.
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"In the 1180s, Strongbow and other Norman magnates helped to fund a complete rebuilding of Christ Church, initially a wooden building, in stone, comprising the construction of a choir, choir aisles and transepts, the crypt and chapels to St. Edmund and St. Mary and St. Lô.\n",
"All medieval collegiate churches or... |
How long did Humans typically go without eating? | I would suggest that you consider cross-posting this to /r/AskAnthropology, as it is less an historical question than one about human physiology. | [
"There is insufficient scientific data on exactly how long people can live without food. Although the length of time varies with an individual's percentage of body fat and general health, one medical study estimates that in adults complete starvation leads to death within 8 to 12 weeks. Starvation begins when an in... |
when movies make hundreds of millions, whats an accurate picture of where this money comes from and where it ends up? | Typically, a writer/producer develop the idea for a film. They take this idea and 'sell' it to a studio for, let's say, 10 $.
The studio will now hire actors, writers (maybe even the same one), producer/directors, sets etc etc etc and spend 50 $ on this all to make a final/finished movie. Since they've spent (50+10) 60$ now, they sell this finished product for a 150 $ to the distributors.
The distributor will now market the hell out of the movie, do ads, trailers, sponsorships, interviews etc etc and will make it look like 'The Next Big Thing'. This cost them 100$. Now cinemas and theaters and 'showers' want the film. They all pay 50 $ each to the distributors to get a copy of the film. Suppose the distributors manage to sell it to 66 cinemas 'WorldWide', so they earn ((66x50)-100)=3200$ from all the cinemas all over.
The cinemas now want people to see the film, so they set the ticket price at 1$ and manage to get 300 people to see the film over the course of 3 weeks at their 20-seat cinema, so they've earned (300 x 1) 300 $ from the film.
The people? They just spent 1 $ and got to see Emma Watson smooching Cristian Bale in IMAX format.
tl;dr
* Idea originator spends effort/time - earns 10. Net +10$
* Studio spends 10 + 50 - earns 150. Net +90$
* Distributor spends 150 + 100 - earns 3300. Net +3050$
* Cinema spends 50 - earns 300. Net +250$
* Audience member spends 1 - earns a movie.
Note: Scales massively distorted for clarity.
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"The film became a blockbuster upon its release, grossing over $32 million, making it the sixth highest-grossing film of 1971 and one of the most successful films in history, with an expense-to-profit ratio of 1:32; beyond that, it is estimated video rentals and purchases in the United States since the 1980s have p... |
When did my Iron Meteorite form? | Iron meteorites formed within a few ~50 million years of the start of the solar system so it's about 4.5 to 4.567 billion years old. | [
"Metallic iron is virtually unknown on the surface of the Earth except as iron-nickel alloys from meteorites and very rare forms of deep mantle xenoliths. Iron meteorites themselves are thought to have originated from stellar bodies larger than 1,000 km in diameter. The origin of iron can be ultimately traced to fo... |
What reactions happen in the brain when someone experiences in 'epiphany'? | When researchers study this, they typically call it "insight" and is often used in the context of problem solving. There are some interesting behavioral aspects of insight: the longer you are working on a problem, the closer you feel you are to a solution, but if you ask people what they think the answer is, they aren't any closer. That is, people have a sense of "I'm about to get this" -- that they are about to have an insight -- but actually we cannot predict when an insight will happen ([Metcalfe and Wiebe 1987](_URL_2_)). To clarify, something special is meant by an insight problem -- it is different from, say, a math problem -- there is no proscribed series of steps to take to reach a solution, you just have an epiphany. For example, problems like rearranging matchsticks that form some Roman numeral equation to form a different equation is an example of an insight problem. Like [these](_URL_4_).
As for what is happening in the brain, there are a number of studies. It seems like activity prior to getting the problem affects ability to solve it ([Kounios, Frymiare, and Bowden 2006](_URL_7_)). This also occurs for lots of other non-problem-solving behavioral tasks in which neural oscillations prior to doing a trial predict performance on that trial (e.g. [Linkenkaer-Hansen et al. 2004](_URL_5_)). It is suggested that prestimulus oscillatory activity may somehow enhance processing once the stimulus appears (perhaps in a resonance sort of way). The exact mechanisms are unclear.
More generally, we can say there is increased activity in certain parts of the brain when you are having an "aha" moment (Qiu et al. [2008](_URL_1_), [2010](_URL_6_)), but that's not really informative for *what* is happening. This activity is different from that observed during non-insight problem solving and it begins a few fractions of a second before the insight strikes ([Jung-Beeman et al. 2004](_URL_3_)), but beyond that we don't really know what is going on. For a review see [here](_URL_0_).
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"Early on, the intoxicant will cause a strong feeling of thirst, followed by weakness, nausea, and loss of appetite. More severe symptoms ensue, including confusion, muscle twitching, and bleeding in or around the brain. Death results by the swelling of the brain against the skull. (Normal serum sodium levels are 1... |
When a person says they're not fat, but big boned, can that actually be the cause for their big size? How much bigger could someone's bones be than that of the average person's, with or without looking fat? | Two different questions here. One, yes some people have larger bone structures. Two, the statement is colloquially used in America by people who deny that they're overweight. The second half of your question, however, delves into social science and observation and I'll get downvoted to hell if I dig deeper into it. | [
"to estimate the fat content. This estimate is distorted by the fact that muscles and bones have different densities: for a person with a more-than-average amount of bone mass, the estimate will be too low. However, this method gives highly reproducible results for individual persons (± 1%), unlike the methods disc... |
do good gut bacteria fight against each other? | Yes! It's definitely an active area of research, but you can be pretty assured that wherever there is a dense, varied bacterial community, they are fighting each other. Certainly indirectly via competition for resources, and in some cases directly by poisoning each other. When there are lots of bacteria growing together all trying to eat and divide as much as they can, everything is an intense competition.
Incidentally, it's probably not that "good" bacteria specifically fight "bad" ones. It's more that many "bad" bacteria just don't have what it takes to compete in the intestine, or at least the competition limits their growth. | [
"The commensal bacteria are nonpathogenic and defend our airways against the pathogens. There are several possible mechanisms. Commensals are the native competitors of pathogenic bacteria, because they tend to occupy the same ecological niche inside the human body. Secondly, they are able to produce antibacterial s... |
Why is it that when a spacecraft docks with the ISS, the force of them docking doesn't disrupt the orbit of the station? | It does! Whenever two bodies in space come into contact, they transfer momentum. Fortunately, when spacecraft dock with the ISS, they use their thrusters to dock at a speed which does not have a significant impact on the overall momentum of the space station. Should the space station's orbit be affected by the docking of a spacecraft, calculations are run to determine if the effect is significant and thrusters on both the space station and docked vehicles are used to re-align the ISS so that it can maintain a stable orbit. This is all calculated and performed using computers so the burn times are very precise - allowing NASA to ensure the ISS remains in a relatively stable orbit.
Fun fact: The ISS has to perform manoeuvres to keep it out of the path of space debris. This can sometimes mean using the thrusters of spacecraft that are currently docked with the ISS. | [
"Docking and undocking describe spacecraft using a docking port, without assistance and under their own power. Berthing takes place when a spacecraft or unpowered module cannot use a docking port or requires assistance to use one. This assistance may come from a spacecraft, such as when the Space Shuttle used its r... |
Would meat ever spoil if we killed all bacteria on it and kept it in a vacuum? | [Neil deGrasse Tyson on Food for Mars Missions](_URL_1_), Neil deGrasse explains how they conserve food in space, and how the texture changes even if no microbes are in the food.
[Tasting Astronaut Food: Inside NASA's Space Food Systems Laboratory](_URL_0_), 20 minute video about space food (but not any real science talk).
edit: Another good video: [Space Food: What Astronauts Eat Today](_URL_2_). | [
"As these microorganisms colonize a piece of meat, they begin to break it down, leaving behind toxins that can cause enteritis or food poisoning, potentially lethal in the rare case of botulism. The microorganisms do not survive a thorough cooking of the meat, but several of their toxins and microbial spores do. Th... |
why do most restaurants/fast food places use foamy soap? | The soap is the same as normal hand soap. It is the dispenser that makes the soap foam. These dispensers help to reduce waste by making it seem like you have more soap than you really do. It doesn't take a lot of soap to effectively wash your hands either. | [
"Because of their intended use in wet and potentially hazardous environments, most soap dishes are designed with safety in mind. Such features include unbreakable materials, non-slip surfaces, rounded edges, and secure installation elements (e.g., wall mount hardware, a suction cup, or non-skid feet). Depositing or... |
In the Andy Williams Christmas song "It's The Most Wonderful Time of the Year" he says "There'll be parties for hosting Marshmallows for toasting And caroling out in the snow There'll be scary ghost stories". Why is he talking about Scary Ghost Stories at Christmas? | The tradition of telling ghost stories at Christmas time is a moderately long one, and – certainly outside the US, where Hallowe'en has often only become a big thing in the last 20-25 years (very much true where I write, here in the UK) – it significantly antedates current conventions.
The key shaper of the Christmas ghost story tradition was Charles Dickens, who for years published an annual ghost story in December, the most famous, of course, being *A Christmas Carol*, in which Scrooge is visited by three very frightening ghosts. There are more than 20 of these tales in all, and, given Dickens's stature as a writer, they proved very influential.
Dickens loved terrifying tales, having been chilled as a boy by the bedtime stories told by his nanny, Miss Mercy – Dickens biographies tend to make much of the impact that her "Captain Murderer" tale made on him, 'which she fiendishly accompanied “by clawing the air with both hands, and uttering a long low hollow groan.”' He was also heavily influenced by childhood readings of *The Terrific Register,* a "wonderful magazine" and precursor to the later Penny Dreadfuls. (I wrote on [the Wonderful Magazine genre here](_URL_0_).) These periodicals, he wrote, made him "unspeakably miserable, and frightened my very wits out of of my head.”
It's hard to trace the Christmas ghost story tradition back before Dickens, but as to why he fixed on Christmas (not a major public holiday until he laid his hands on it) for his tales, Vic Zoschak [suggests](_URL_1_) that he was tapping into an older tradition, dating back at least to the late 16th century, associating ghosts and winter.
Dickens's Christmas ghost stories have been collected and republished: *Ghost Stories,* edited by David Stuart Davies, London: Collector’s Library, 2009. A good guide to the genre is Andrew Smith's *The Ghost Story, 1840-1920: A Cultural History* (Manchester University Press, 2010).
For many people Dickens's most effective and most frightening ghost story is "The Signalman," which is readily available online - for instance [here](_URL_2_). I don't suppose he'd mind you reading it aloud this Hallowe'en, rather than waiting for Christmas. | [
"A number of reviewers had a problem with \"Do They Know It's Christmas?\" being set in a homeless shelter; both Hyman and West called it an \"odd choice\", and Slezak said he \"struggled\" with the location. Chaney called the lyrics \"condescending\", and found the juxtaposition of the singers' smiling faces and t... |
To what extent can/do multiple strains of an illness (like 2 different kinds of the flu or 2 colds for example) infect a person at the same time and compete for control of their body? | For something like the flu or a cold if the viruses have different target cells they probably don't compete much. They are just waiting until they find the right cell type to replicate.
As for bacterial pathogens there would be a lot of competition for limiting nutrients, such as iron, with not only our cells but our normal Flora.
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"Infection with one genotype does not confer immunity against others, and concurrent infection with two strains is possible. In most of these cases, one of the strains removes the other from the host in a short time. This finding opens the door to replacing strains non-responsive to medication with others easier to... |
why is the default stressful dream "unprepared in high school" for so many people? | I think it's because school is the first time people are "graded" based on effort entirely within their social circle they are immersed in daily.
It's not just hormones causing you to feel uncomfortable, anxious and stressed, but you also have to compare your worth against people who are your peers, which probably smacks to tribal instincts of not failing the pack and being the weakest link.
Being prepared for the hunt made the pack like you, not being prepared meant you were a pariah and were an outcast. So effectively it's tribal instincts, bolstered by increasing hormonal imbalances, with a pinch of unrealistic expectations that kids put on themselves when they consider that their entire life is spawning from their grades at school. | [
"An optimal level of stress is considered good because medical students develop coping abilities. However, too much stress causes problems. Previous studies have reported that a significant percentage of medical students suffer anxiety disorders because stress has a strong relationship to emotional and behavioral p... |
Did any non-Austrian influenced Italians (i.e. Scicilians) oppose unification in the 19th century? | When the unification movement started, Cavour only wanted Piedmont to annex what was North of Rome. He practiced Realpolitik, which meant he was interested in tangible results and all of his actions were calculated. Garibaldi, a Romantic Italian, wanted unity for all of Italy. Garibaldi sent his army of Red Shirts to the Southern tip of Italy and they fought towards the North. Everywhere they went, the people asked to be annexed by Piedmont. He annexed all these lands. When Garibaldi and Cavour met halfway through Italy, he figured he might as well compromise and take the southern lands. So in a way, there were people opposed to total unification. The Italian state later received help from the French to annex Venice from Austria and Rome from the Pope.
Source: Ronald R Palmer, A History of the Modern World.
If anyone wants to correct something, please do, it's been a while since I took Euro and I don't have time to look at my notes at the moment. | [
"At the time, the struggle for Italian unification was perceived to be waged primarily against the Habsburgs, since they directly controlled the predominantly Italian-speaking northeastern part of present-day Italy and were the most powerful force against the Italian unification. The Austrian Empire vigorously repr... |
why does a phone need to be charged above 15% to take a picture? | First, phones make some assumptions about the battery. They might know the charge level, but they calculate the rate they are draining at based on current activity. So if you fire up the camera and sees that the drain-rate goes up, the phone might go "Uh oh, I'm about to lose power" and warn you. Using the camera means the screen is on, which is the most battery draining thing a phone can do.
I still don't see that a phone would *prevent* you from using the camera. I've used the camera on my phone when it was well below 15%, on quite a few phones. Unless you have an oldish phone with a failing battery and it actually drains enough to shut itself down, it should just put up a "low battery" warning you can dismiss and keep using it. | [
"However, Luke Hopewell from Gizmodo Australia wrote in reply: \"Yes it's heavy, but it's something you get used to. Sam said that the phone is too heavy to even contemplate living with, and that's almost true. If you can get past the weight of the device, you're in for a treat. The weight is almost beneficial when... |
What was the largest slave plantation in history? | Just briefly reviewing this [book](_URL_1_) which also has the 223 figure as the average size I would think that there would be no plantations significantly larger than the average given that:
1) in jamaica the top 1% of slave owners (119) had 45025 slaves suggesting an average size of the largest plantations of ~378 which was not significantly larger than the average and doesn't suggest a very large standard deviation
2) the average size of sugar plantations in general was 100-250 slaves in total
3) the average size of coffee plantations was even smaller with an average size of 42 slaves in Guadeloupe
4) large plantations seemed to decline over time especially where we have solid data such as in Cuba so it seems improving technology and a turn away from slave labor especially after Britain's ending of the slave trade would have precluded the development of large slave plantations like in the American south
5) [large mortality rates](_URL_0_) in sugar plantations would have made it difficult to sustain a large workforce; I suspect disease was also a factor that was not seen in the American south
Just ballparking the statistics I would be stunned if there was a larger sugar plantation in the Caribbean then in the american south. | [
"The 1860 U.S. Census counted 3,605 slaveowners in West Virginia. Of this number 2,572 (71%) owned 5 or less. These owners accounted for 33% of the total number of slaves. In 15 counties there was a total of 92 owners of 20 or more slaves. The greatest numbers of slaves occurred in the counties of Jefferson (3,960)... |
For experts about the American Revolution in the South--what happened to the British soldiers who were stationed in Charleston when the Revolutionary War started? | I'm afraid the answer is disappointingly simple: there were no British regulars in Charleston in 1775, and by the time open fighting began, the British had other worries than immediate reconquest of a somewhat insignificant town.
The pre-war British army was quite small, numbering just under 50,000, and most were in Ireland or England itself at the outbreak of war. The vast majority of North American cities lacked British garrisons. There were not much more than 10,000 (I can't find an exact number) British soldiers in North America on the eve of war. The largest concentration was in Boston, where the British had been gradually building up troops since 1769 in response to growing tensions. Many of these regiments came directly from England or Ireland, but it also required the diversion of troops from New York (which was stripped to nothing) and Halifax (now Canada). The remaining British troops in North America were garrisoning modern Canada, the Caribbean, or former Spanish Florida, with a handful at frontier posts like Fort Ticonderoga in upstate New York.
By the by, the British bombarded and were repulsed by Fort Moultrie, an improvised fort on Sullivan's Island. Fort Sumter was built in the 1850s on an artificial island in Charleston harbor. | [
"Revolutionary War pension applications and colonial records provide considerable information on the South Carolina militia units and officers, and the battles in which they fought. When Charlestown fell on May 12, 1780, most of the generals were taken as prisoners by the British and the regiments were left to fend... |
In Western Europe in the 16th/17th centuries, how achievable would it have been to 'pretend' to a higher status? Are there examples of people doing so? |
Perkin Warbeck as Richard of York:
Not only did young Perkin Warbeck masquerade as a prince, he nearly succeeded in overthrowing King Henry VII of England. In 1491, Warbeck appeared in Ireland claiming he was Richard of York, the youngest son of the former King Edward IV. The real Richard was most likely murdered in the Tower of London as a boy, but at the time there was still much speculation about his fate. Capitalizing on this mystery, Warbeck presented himself as the missing prince, and eventually won support among Henry VII’s political enemies, who included such powerful figures as James IV of Scotland and Maximilian I of Austria.
Warbeck landed in Cornwall in 1497, and he soon galvanized his supporters into a rebel army of several thousand men. But when faced with the possibility of a battle with the king’s forces, the pretender lost his nerve and fled to the coast. He was eventually captured, and later admitted he was an impostor before being executed by hanging in 1499. Warbeck is widely regarded as a famous fraud, but some historians have noted that Henry VII could have fabricated the pretender’s backstory in an attempt to discredit him. With this in mind, there remains at least a small possibility that Warbeck may have actually been Richard of York.
_URL_0_ | [
"The term \"pretender\" may apply to claimants with arguably genuine rights (as the various pretenders of the Wars of the Roses who regarded the \"de facto\" monarch as a usurper). It may also be used for those possessing an arguable right to a position who do \"not\" actively claim it, as well as impostors with wh... |
How oppressive was Lee Kuan Yew's government? What questionable policies did it enforce? | Follow-up question:
What are the best books to read to begin studying about LKY?
I've watched his interviews on Charlie Rose and I find I am utterly fascinated by him.
Thank you! | [
"Led by Hong Xiuquan, the self-proclaimed brother of Jesus Christ, the goals of the Taipings were religious, nationalist, and political in nature; they sought the conversion of the Chinese people to the Taiping's syncretic version of Christianity, the overthrow of the ruling Manchus, and a wholesale transformation ... |
how do wet dreams cause one to cum if there is no sexual pleasure in reality? | Sexual pleasure is mostly in the mind. Your dreams are fully capable of providing that. What little contact is needed for wet dreams is provided by your underwear/other clothing, sheets, or actually masturbating in your sleep. | [
"The Hall data analysis shows that sexual dreams occur no more than 10% of the time and are more prevalent in young to mid-teens. Another study showed that 8% of both men and women's dreams have sexual content. In some cases, sexual dreams may result in orgasms or nocturnal emissions. These are colloquially known a... |
During the Three kingdoms period, was Lu Bu real? And was he as strong as people say he was? | Lü Bu was a real person, yes. Chen Shou's *Sangouzhi* (三國志, Records of the Three Kingdoms, written in the 3rd century) mentions him, and that's pretty much the most cited historical document for the time period/location.
While the site itself is mostly dedicated to Luo Guanzhong's *Sanguo yanyi* (三國演義, Romance of the Three Kingdoms) and the games by Koei Corp. (Romance of the Three Kingdoms, Dynasty Warriors, etc), it does provide English translations of the Sanguozhi, and here is Lü Bu's:
_URL_0_
From my reading of it, it seems that yes, Lü Bu was very much a skilled and powerful warrior. Luo Guanzhong may have been a bit biased towards painting Liu Bei in a sympathetic light (Liu's pity towards Lu Bu, wanting Liu to appear gentle), and in the novel Lü seems to be a bit more... brutish and stubborn, which the video games definitely capitalize on.
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"In the 14th-century historical novel \"Romance of the Three Kingdoms\", which dramatises the events before and during the Three Kingdoms period, Lü Bu is portrayed as a nearly invincible warrior but an incapable leader who is further marred by character flaws. While adhering to historical records in the general co... |
Hypothetically, could anaphylactic shock be treated by sending the victim bungee-jumping or other adrenaline-inducing experience? | Another question: Wouldn't the fact that you probably think your dying during anaphylactic shock cause you to pump out adrenaline anyway? Why doesn't this solve its own problem? | [
"Anaphylactic shock requires advanced medical care immediately; but other first aid measures include rescue breathing (part of CPR) and administration of epinephrine using an EpiPen for immediate administration of epinephrine (adrenaline) to reverse swelling and to keep the respiratory airway (trachea) open.\n",
... |
how does picture format conversion work? eg. png to jpg | It's basically the same as translating languages. A program knows how to read and save both formats and remakes the original in the other format. | [
"JPEG uses a lossy form of compression based on the discrete cosine transform (DCT). This mathematical operation converts each frame/field of the video source from the spatial (2D) domain into the frequency domain (a.k.a. transform domain). A perceptual model based loosely on the human psychovisual system discards ... |
why is it that every device i own slowly but surely slows down and refuses to work like they once did no matter what i do? shouldn't upgrades and better technology ensure longer lifetimes for gadgets, not kill them off and force me to buy new ones? | I'll start off with a little anecdote. I was on the train when a woman was talking to her coworker about how "every company does planned obsolescence," and while this is true to a small and shady extent, she used it as an excuse for her phone slowing down and battery life getting shitty which is wrong.
Let me explain by using phones as an example and then we can talk about other gadgets. When a phone is made, it may have say 100 units of processing power. It also has 100 units of battery. The operating system may only take 5 units of processing power, so here's the thing. When the next version comes out, it will require more processing power, but if a manufacturer optimizes it, it won't be too bad a difference. For google nexus phones, google might update my phone to Android M, but will make sure it only takes up 7 units of processing power. Samsung may give their Android M update which takes 12 units. This is called optimization. When you make new software work as best as it can for old stuff. This is why people like Apple and Google Nexus phones, because both companies actually care to optimize for their phones over time to the best of their ability. Samsung may not care because it just motivates you to get their latest and greatest product. For android phones, there are communities that make the latest software available for phones from 2010 since they do the optimizing themselves. That's an example of how long a phone can truly last because they're running lollipop relatively smoothly.
Here's the thing, with batteries, you may start out with 100 units of battery, but after a year it goes down to 70 because of the chemical limitations of the battery itself. You can't fix that with a software update. What you can do is buy a screwdriver, look at a guide online and replace the battery with a fresh one.
In order to deal with what your question asks, I usually do some research on whether an update slows down on my hardware. This way its better for me to stay on old software, say for my car, because if I updated that GPS system, it would probably slow down so the manufacturer would try and convince me to buy a new car. Most of the time, its software that is your issue with these types of technology. With some research, you can find out the best way to keep your stuff running super fast.
There is also the issue that most people don't know how to properly maintain their device. For windows think of a computer with tons of startup programs, cluttered folders, and filled registry. For Android, think of a phone with a shitton of useless apps that keep causing random wakelocks. When you add all this crap software that takes away from battery, over time your performance will decrease and so people will blame the manufacturer for making a shitty device. | [
"In some cases, technology is accessible but sufficiently complex that most users without specialized training are able to operate it without necessarily understanding how it works. Additionally, the process of consumerization has led to an influx in the number of devices in businesses and accessing private network... |
When did garbage collection become a common feature in American cities? What did people do with their refuse before that? | TL;DR: Roughly 1880 - 1890, starting largely in New York City.
For a brief overview, [A Filthy History: When New Yorkers Lived Knee-Deep in Trash](_URL_5_) gives a pretty good outline, and is a review of a book, [_Picking Up_](_URL_1_), by Robin Nagle, with much more detail.
In the late 19th century, garbage consisted not just of packaging and discarded materials, but to an immense degree animal waste, and carcasses. New York City itself had a fleet of over 200,000 horses which transported virtually everything within the city, including goods moved from rail depots. The automobile hadn't yet been developed, electric streetcars were in their infancy (though had, just, been invented), and the development of rail actually _increased_ demand and populations of horses as last-mile transport.
Each horse produced vast amounts of liquid and solid waste, collectively about [100,000 tons per year of the latter, and a million gallons of urine](_URL_0_) , and being hugely overworked, frequently died, and were left on, the streets.
The political and social angles of the cleanup were also notable -- the first sanitation commissioner, George Waring, not only created a military-like hierarchy and discipline, but issued uniforms, _white_ uniforms, for association with cleanliness and hygiene, to the workers.
Prior to organised city services, trash disposal was up to individuals and households, who often incinerated refuse, or to independent operators who often serviced only selective classifications, e.g., rag-pickers.
The total tonnage of refuse per person was actually higher in the 1930s than it is today, though a huge fraction of that, about 40% by weight, was coal ash, from heating. The conversion to fuel oil and eventually natural gas hugely reduced that, and also allowed the replacement of formerly stainless steel (and fireproof) "ash cans" with today's mostly plastic recepticals.
(I need to find the source for this in my notes, I'll update when available.)
Sanitation reforms -- municipal waste pick-up, establishment of fresh-water and sewerage systems, and other public health measures all accounted for a dramatic decrease in mortality in New York. The graph [The Conquest of Pestilence in New York City](_URL_3_) is a favourite of mine to show to those who think that the majority of health improvements have been recent. Truth is that most pre-date 1920.
[Recycling began in New York City as a voluntary measure in 1986](_URL_2_), though the first classified disposal system dated from nearly a century earlier (ash, food, and other solids) as [this timeline highlights](_URL_4_).
The use of plastics post-dates their invention, most between 1920 and 1930 at DuPont Chemical.
Though I've focused on New York city, most other waste, sanitation, and hygiene projects in the US followed that city's lead. | [
"Similar municipal systems of waste disposal sprung up at the turn of the 20th century in other large cities of Europe and North America. In 1895, New York City became the first U.S. city with public-sector garbage management.\n",
"Similar municipal systems of waste disposal sprung up at the turn of the 20th cent... |
how does having sickle cell protect against malaria? | We don't know exactly, but it has something do do with the fact that the Malaria parasite lives in the red blood cells for part of their development.
There are different theories, but they basically come down to one of two things:
* Either the red blood cells of people with sickle-cell disease are just more difficult for the parasites to live in.
* Or the red blood cells are more sensitive so that the parasites damage them and the body recognizes them as defective and recycles them before the parasites can complete their development. | [
"The impact of sickle cell trait on malaria immunity illustrates some evolutionary trade-offs that have occurred because of endemic malaria. Sickle cell trait causes a change in the hemoglobin molecule in the blood. Normally, red blood cells have a very flexible, biconcave shape that allows them to move through nar... |
What was the lifelong illness that plagued Augustus? | Could you explain why you think that Augustus suffered from a lifelong illness in the first place? | [
"Augustus fell dangerously ill in 23 BC and did not expect to recover. The model of late imperial succession suggested that the closest male relative would succeed, despite the fact that Marcellus had held no office and lacked military experience. His marriage to Augustus' daughter seemed to be a strong indicator, ... |
How come North and West are common English surnames, but not East and South? | Hello everyone. Just want to give a quick heads up as to why there are a bunch of removed comments, because people keep asking. Here are some of the removed comments, in their entirety:
> Damn it. I need an answer.
> WHY IS EVERYTHING REMOVED? Every time I’m genuinely curious :(
> Geez, what happened here?
Most of the removed comments are that in different variations. Then there are the RemindMe! comments:
> Remind me in 5 days
Which by the way don't often work here because the remind me bot is banned and AutoMod removes remind me posts immediately when they get posted. I think that's also the wrong format for the bot anyway.
There are two comments naming people with these surnames, consisting almost entirely of these names, without actually answering the question as to why theyre relatively rare.
There is one comment which has confused Kanye West's kid's given name for a surnam.
And then there's this "answer":
> cuz
So don't worry. As of right now, you are missing absolutely nothing.
We ask that answers in this subreddit be in-depth and comprehensive, and highly suggest that comments include citations for the information. Comments which don't answer the question at all also get removed. So far, there has not been a single serious attempt at answering the question at all, which is why you aren't seeing an answer yet.
Give it time. The post is only 6 hours old. It often takes closer to 12.
Please don't leave additional garbage comments. That will only make the graveyard bigger.
**edit:** If you'd like to have a discussion about "answered" flair and the like, check for the most recent [meta] thread on that topic. It gets posted every week or two. This isn't the right place for it because, again, its just adding to the comment count with more comments that aren't answers to OP's question. | [
"BULLET::::- In most of the eastern half of England, plurals and past participle endings which are pronounced and (with the vowel of \"kit\") in RP may be pronounced with a schwa . This can be found as far north as Wakefield and as far south as Essex. This is unusual in being an east-west division in pronunciation ... |
the physics that make the double bounce on a trampoline so effective and at launching kids so high in the air. | When you land on a trampoline, the weight of your body landing loads the webbing and springs with potential energy.
More people landing on the webbing at the same time creates more potential energy on the trampoline.
Once those other people jump, all that potential is passed to the person in the middle, where most of that energy is focused and boom goes the dynamite. | [
"Trampolining or trampoline gymnastics is a recreational activity, acrobatic training tool as well as a competitive Olympic sport in which athletes perform acrobatics while bouncing on a trampoline. In competition, these can include simple jumps in the straight, pike, tuck, or straddle position to more complex comb... |
Would fighter jets experience G forces if they fought in space? For example, would it be possible for the x-wing pilots in star wars to black out from over G's? | Absolutely they would. G-forces, as they're referred to in air-to-air combat, are the forces experienced by the pilot due to centripetal acceleration as they make tight turns, and for brief periods can exceed 5x the force of gravity.
In space, there wouldn't be the constant downward force of gravity, since we're presuming that we're out of the range of any gravity from Earth or another planet.
So yes, if the X-Wing pilots were doing sharp enough turns, for long enough, they might experience G-forces that would make them black out. | [
"Later jets such as the F-15 Eagle, F-16 Fighting Falcon, F/A-18 Super Hornet, Eurofighter Typhoon and the Dassault Rafale can sustain high g loads for longer periods, and are therefore more physically demanding. By using a modern g-suit in combination with anti-g strain techniques, a trained pilot is now expected ... |
why the u.s. is going after fifa, but none of the international big banks? | With the FIFA scandal, the issue can be traced back to certain individuals who took bribes and against who they have proof. (though it has not actually gone through a court of law yet, so we don't even know what charges they will eventually end up with)
With the banking crisis, it is much much harder to point at a single individual who was at fault. These issues exist because multiple people are at fault, creating a culture that leads to it. You can put as much fault for the financial crisis with the American government and their policy changes under the idea of 'everybody needs to be able to be a home-owner'. Additionally, while we can say certain policies were at fault for causing the crisis, they weren't actually illegal, just irresponsible. You cannot arrest people for things that aren't illegal, just like we can't arrest you for not studying for an exam. Sure, we can now all say that it was completely stupid to give mortgages to people who were unable to pay back that amount, but it wasn't illegal.
(also, it is not correct to say nobody was arrested for the financial crisis. There were some arrests and convictions when there was actual proof of illegal acts. Michael J. McGrath Jr and Lee B. Farkas are two) | [
"One condition FIFA imposed was the creation of a professional football league – Major League Soccer was founded in 1993 and began operating in 1996. There was some initial controversy about awarding the World Cup to a country where football was not a nationally popular sport, and at the time, in 1988, the U.S. did... |
How are the fundamental forces related, and how does the weak force fit in? (many questions) | > From what I understand, gravity has one property (sorry I don't have a better word for this) and reaches it's lowest energy state when anything displaying this property (mass) is brought close together. Electromagnetism has two properties, positive and negative charge, that reach lower energy states when brought together creating something neutral. The strong force has three properties (red, green, and blue) that are most energetically favorable when brought together to make something white. Is the weak nuclear force a continuation of this pattern with 4 different properties, or is it something entirely different?
Gravity is special, and is not described by a gauge theory in the Standard Model of particle physics, so I'll leave that out for now. Technically electromagnetism has one charge (there is a charge and an anti-charge), the weak force has 3 charges, and the strong force has 8 charges. Note that things are a bit more complicated than you describe with the red/green/blue description of the strong force. For example, there is red/anti-red and blue/anti-blue and green/anti-green, which also are energetically favorable when brought together. Note that gluons in addition to quarks also carry charge, and their charges are combinations of colors and anti-colors. So you see the description in terms of colors is not simple, and it is a stretch to try to understand things in the way you describe.
> Since the gluon, photon, and presumably graviton are massless, why are the W and Z bosons massive? Why is there two instead of one force carrying particle?
The number of force carrying particles always equals the number of charges. Electromagnetism has one charge, so there is one force carrier: photon. Weak has 3 charges, so there is the W+, W-, and Z. Strong force has 8 charges and 8 gluons. The W and Z bosons are massive because of the Higgs mechanism, which breaks electroweak symmetry (which would otherwise prevent them from having mass).
> Magnetism, from what I understand, is a result of relativistic effects on the electric force, is there anything comparable for the other forces? Also, what does it mean for photons to carry both charge and magnetism?
The modern understanding is that electricity and magnetism are aspects of the same thing: the electromagnetic field. It is wrong to think of them as distinct. They are mixed into each other by changing reference frames, and relativity teaches us that there is no preferred (inertial) reference frame. The fact that magnetism can be shown to be a relativistic effect of the electric force, is something that is true in one reference frame. But in another reference frame, the electric force can be shown to be a relativistic effect of magnetism.
For gravity there is such a thing as Gravitoelectromagnetism (you can look it up in wikipedia), but the analogy only goes so far. There is not actually a gravitoelectromagnetic field, the Maxwell-like equations are not Lorentz invariant, there is no such thing as a gravitomagnetic monopole, etc.
There is probably something similar for the weak and strong forces, but I have never heard it referenced. (That is an interesting question, I imagine it would be extremely complicated and abstract. Keep in mind that the only reason magnetism is interesting to us is because we produce electric currents on a macroscopic scale. We don't produce similar weak or strong force currents, where the effect might be detectable. Also keep in mind that the weak or strong force + relativity is sufficient for all predictions, so technically it would not be necessary to develop all of the theory behind such a thing).
> Grand unified theory describes three forces as a result of one interaction, what does this interaction look like?
We don't have a grand unified theory. But we have examples of unified forces. Think of the unification of electric and magnetic forces. But the technical answer to your question is that in the Standard Model the forces are associated with the U(1), SU(2) and SU(3) gauge groups. In a grand unified theory, the forces would be associated with one larger gauge group such as SU(5). In such a case there would be 24 charges, and things would be much more complicated, and somehow everything would reduce to looking like U(1), SU(2) and SU(3) at our energy scales. So far such theories don't work so well; they predict stuff like proton decay and unobserved exotic particles.
> Before the forces froze out of the early universe, would there be fewer force-carrying particles, would they travel as composite particles (ie. gravitons and photo-gluo-W/Z-ons), or something else entirely?
They would still be there, but they would act very differently at that energy scale. The physics changes at different energy scales (see: running couplings).
> Can high-energy experiments ever recombine forces, or is their separation a property of the universe as a whole?
High energy experiments can probe different energy scales. You can measure the strength of forces at different energy scales, and it may be that at some high energy scale different forces start behaving similarly. It may be that this reflects a common origin of the forces. Ultimately of course the separation of forces at low energy is a property of the universe, but it may be that at low energies it is just not obvious anymore that these forces are very closely related.
> Lastly, is it acceptable to model particles as waves in fields that act like particles when they're forced to be quantized? (Ie. their nature is fundamentally wave-like, but is forced to assume particle-like behavior when observed?)
What do you mean by "acceptable"? In the Standard Model, all particles are modeled as waves in fields. Upon measurement, there is the "measurement problem" and the question of various interpretations of QM. But in a calculational sense, we can simply treat everything as a wave in a field until measurement, and then use the Born rule to predict the outcome of measurement. | [
"The weak force is due to the exchange of the heavy W and Z bosons. Its most familiar effect is beta decay (of neutrons in atomic nuclei) and the associated radioactivity. The word \"weak\" derives from the fact that the field strength is some 10 times less than that of the strong force. Still, it is stronger than ... |
Does cognitive ability such as memory, processing decline as we age? | There are two ways to look at it. Synaptogenesis, which is the process of forming new synapses, declines sharply after infancy and throughout childhood, but then accelerates again in adolescence. It drops off again as you enter adulthood and continues to decline across adulthood. This means it is harder for you to make large changes to what you know and how you think.
However, this decline has its virtues. The opposite of synaptogenesis is apoptosis, the degrading and removal of unused synapses. This appears to support specialization or fine-tuning of specific cognitive abilities. Too much flexibility can be bad for specialization. (The metaphor I always use is that of a car that has a separate steering system and set of pedals for each wheel. A car like that is more flexible in what it can do. It might be nice for some things like parallel parking, but it would be nightmare to drive most of the time. So flexibility is not always an advantage.) Apoptosis, therefore, should be considered a feature and not a bug. It is part of normal and healthy brain development. Physical brain maladies like plaque buildup associated with advanced age, however, don't appear to have an upside like apoptosis does.
**TL;DR ** Cognitive flexibility and potential to learn new things declines as we age, but certain cognitive faculties can continue to be honed and improved throughout adulthood. However, old age is associated with overall decline.
EDIT: Some practical advice regarding these changes associated with adulthood:
1. Education. Higher education is associated with delayed cognitive decline in old age, even in the case of diseases like Alzheimers.
2. Cardiovascular exercise. Cardio has been linked to adult neurogenesis (creation of new nerve cells) in adults.
3. Try new things. You can force yourself to keep somewhat flexible by seeking out new experiences and new learning opportunities.
4. Socialize. Having friends
4. Pursue things you want to be good at. Somewhat contradicting #3, if you're worried about losing your math abilities, do math. If math is not an important part of your career or hobbies, consider abandoning it in favor of pursuing what you're good at, or would like to be good at. There is not much evidence to suggest that there are any "brain exercises" you can do that transfer to other activities. For example, doing crossword puzzles will make you good at crossword puzzles, but probably won't do much for your ability to, say, write speeches.
EDIT 2: WRT memory, it appears that it is easier to memorize things for younger people, but, given the turnover of synapses associated with youth, memories that are not used probably disappear more quickly in young people. Think of how quickly a toddler learns a language, yet is unable to recall events from toddlerhood just a few years later. The difference is, the language usage is constantly reinforced, while specific memories of events are not. Compare this to an adult, who has a very hard time learning a new language, but can remember events from a couple years ago in a way that toddlers cannot. While there are many exceptions to this of course, it is another illustration of how the cognitive changes in early and mid adulthood are advantageous is some ways. | [
"Working memory is among the cognitive functions most sensitive to decline in old age. Several explanations have been offered for this decline in psychology. One is the processing speed theory of cognitive aging by Tim Salthouse. Drawing on the finding of general slowing of cognitive processes as people grow older,... |
What is the highest velocity an object in space can travel at before relativistic effects take place (or become a problem?) | It depends what you mean by noticeable. In order to experience a 1% change in elapsed time or distance, you'd have to be going 14% the speed of light. | [
"Sources conflict about the projected speed, perhaps 30% of the speed of light, \"c\", but 9% may be more likely. At 30%, relativistic effects between people on Earth and on the spacecraft, such as time dilation would become more noticeable, such as the shipboard time being less than the Earth observed time.\n",
... |
how do natural fields exist? (more specifically, ones found in the middle of forests.) | It's part of ecological succession. Environments are constantly changing. It's a system that is complicated by an almost infinite amount of factors and conditions. Usually a glade represents an area that recently changed so that it could no longer support the other surrounding plants. This could be because of poor soil, a forest fire, aggressive feeders, disease, strong wind or snow. When an area is cleared, pioneer plants take over. This will include some trees, but it will take awhile for them to grow tall enough to be more permanent fixtures. Eventually, enough trees will grow so that canopy cover is achieved. At that point, the trees might have grown so dense that they block too much sun and the soil becomes poor. This will cause some trees to die. Shade tolerant plants will start to make a significant appearance once the trees' population dynamics even out around their carrying capacity. After the shade plants, more plants will arise, each changing the former glade in some way that allows more species to grow and some to die back. Eventually, climax community is reached or another dramatic change happens that causes a significant portions of plants to die. | [
"A forest consists of many components that can be broadly divided into two categories that are biotic (living) and abiotic (non-living) components. The living parts include trees, shrubs, vines, grasses and other herbaceous (non-woody) plants, mosses, algae, fungi, insects, mammals, birds, reptiles, amphibians, and... |
I'm looking for examples (Sources) of literature which typify Colonialist attitude? To use as a reading in Church. | Hi! I think the best example i can think of would be Rudyard Kipling's *White Man's Burden*. You can find it on the internet but here's a link anyway:
_URL_0_
Cheers! | [
"In Elizabethan England, no subject was more familiar to writers than theology. Elizabethans learned to embrace religious studies in petty school, where they \"read from selections from the Book of Common Prayer and memorized Catechisms from the Scriptures\". This influence is evident in Spenser's text, as demonstr... |
Was illegal immigration around in the US during the late 1800s and early 1900s? | Immigration was first regulated on a mass scale in [1892](_URL_2_), when the requirement to be registered at Ellis Island was created. Immediately illegal immigration came into existence. The term "wop" for Italian-Americans derives from ["without papers"](_URL_3_) and dates from 1908. "Wetback" for Mexican-Americans who swam the Rio Grande was first recorded in 1920. _URL_1_
However, most immigrants could enter without having to be illegal until the quota system was established in [1921](_URL_0_), capping the numbers of all immigrants. Variations of the quota system are what make illegal immigrants illegal today. | [
"Shortly after the U.S. Civil War, some states started to pass their own immigration laws, which prompted the U.S. Supreme Court to rule in 1876 that immigration was a federal responsibility. The Immigration Act of 1891 established an Office of the Superintendent of Immigration within the Treasury Department. This ... |
When Hernan Cortez and the Spaniards arrived in the Aztec empire in 1519, it is been said that Cortes was taken to the king of the Aztecs and told them he was a peaceful emissary sent by King of Spain. How was this information relayed to the Aztecs linguistically? | There’s one quite clear answer to this: the Spaniards communicated at first via two translators, the Spaniard Géronimo de Aguilar and the Nahua woman Malinche/Malintzin (also "Marina" to the Spanish). For a few years before Cortés reached modern-day Mexico in February 1519, other conquistadors had already been sent from Cuba. They staked out parts of Yucatán e.g. in 1517 under Hernández de Córdoba, and included a certain Bernal Díaz de Castillo, whom I’ll return to, as well as the mentioned Aguilar.
Matthew Restall has a good discussion of the role of interpreters in the Spanish American conquests in his « Seven Myths of the Spanish Conquest » (ch. 5). He mentions that Aguilar who had been stranded in Yucatan spoke Mayan and Malinche knew Mayan and (the main Aztec language) Nahuatl but little or no Spanish – so that Cortés communicated with Nahuatl speaking lords through the triangle of his two interpreters.
For the timeline: it took the Spaniards a few months after their initial landing near modern-day Veracruz to get to Tenochtitlan, the capital of the Aztec Triple Alliance. Moctezuma was the ruler of the Mexica, the dominant group of the larger Alliance at the time that controlled parts of central Mexica. During that time come various battles and diplomatic exchanges occured, all exchanges made possible by Malinche and later a few other translators who learnt Spanish. And Cortés already told the Aztec rulers he negotiated with early on that he was a peaceful emissary of a “great ruler” overseas – so that according to Cortés (and native accounts), Moctezuma already knew about this well in advance.
The three-way system of translation was clearly imperfect but still allowed for basic communication. Over time, Malinche’s Spanish improved so that she probably served as the main translator by the time the Spaniards reaches Tenochtitlan. Restall uses this example to challenge myths of both the Spaniards' “superior” communication skills, and of supposed extreme miscommunication taking place. Interpreters played similarly important roles in Pizarro's campagins in Peru, as well as in other Spanish American regions.
*This is my short overview over the translation issue. Since Malinche/Malintzin is a very complex person I’ll discuss what we know of her a bit more below, for those interested.*
----
& nbsp;
Cortés himself mentions **Malinche** only twice very briefly, but her importance comes through in later indigenous sources. In early colonial source like the Florentine Codex, Cortés is often referred to as “El Malinche” and his translator as “La Malinche” – indicating that the translator through whom Cortés spoke had attained respect and importance among Aztec elites. She is even sometimes referred to simply as “la lengua”, the language.
In the painted Lienzo de Tlaxcala, made ca. 40 years after the conquest period, we find[ a great image of the first meetig of Moctezuma and Cortés](_URL_3_). Here Malinche stands behind Cortés and on the same level, indicating how Tlaxcalan nobles of the later 16th c. would have seen her nearly on par with the Spaniard - after all it is her their ancestors were talking to. At the same time, our knowledge of Malinche is quite limited by the source accounts we have, most of them like those just mentioned not contemporary.
We don’t even know her exact name for sure: she was given the Spanish name Marina by the Spaniards. Due to various pronounciation issues with Nahuatl this became Malintzin for the Aztecs/Nahua (with Nahua a name often used for Aztec people in current literature) – with -tzin a respectful addition; and some Spaniards then called her Donha Marina since they had in turn difficulties pronouncing the Nahuatl -tz. As Nancy Finch says, “There is little evidence that the Spanish either knew or cared what name her parents had given her.”
Her background is similarly difficult to know. Cortés simply calls her “an Indian woman” and leaves out the honorific Donha. Generally though Cortés mentions any of his indigenous allies that numbered in the hundred thousands very little, so this is not so surprising. The only contemporary account is by the above mentioned Bernal Díaz. For Díaz, Malinche was a noblewoman from the town Paynala who had been sold into slavery to a group in Tabasco, who in turn gave her to Cortés. This is a well-known version (since Díaz work is well known), but other accounts contradict it.
For example, the Tlaxcalan chronicler Diego de Munhoz Camargo writing decades after the conquest lists various possible biographies: including on where Malinche was simply a commoner or enslaved woman from Tabasco. We will probably never know her origins for sure, but it is clear that due to her important role for the Spanish she was seen as a noble or high ranking person by her indigenous contemporaries. Her centrality comes through clearly in Díaz, who described her with respect:
> Doña Marina knew the language of Coatzacoalcos, which is that of Mexico, and she knew the Tabascan language also. This language is common to Tabasco and Yucatan, and Jeronimo de Aguilar spoke it also. These two understood one another well, and Aguilar translated into Castilian [Spanish] for Cortes.
> This was the great beginning of our conquests, and thus, praise be to God, all things prospered with us. I have made a point of telling this story, because without Doña Marina we could not have understood the language of New Spain and Mexico.
At a later point, Díaz also discusses the major Spanish massacre at Cholula. He describes a supposed plot by Mexica emissaries that could only be thwarted through Malinche’s translations, leading to the infamous massacre. (NB that it’s very likely that Cortés used this more as an excuse for exemplary use of violence, as he does at various points throughout his campaign). Again,[ another image from the Lienzo de Tlaxcala](_URL_0_) shows Malinche's centrality to the event, even directing Spanish troops. While this goes beyond what Díaz describes and may speak more to how Tlaxcalans in the mid 16th c. wanted to paint Malinche, it does show how her role would subsequently be highlighted by native nobles.
So while we know not a lot about Malinche’s background, we can say that through her position she became a respected person with a quite high status in colonial times. Since she was originally a slave it’s difficult to uphold modern claims of Malinche having somehow “betrayed” her own people – while an important (or rather essential) actor in the campaign, it would have been probably impossible to go against the wills of the Tabascans and later the Spanish.
There are certainly a lot of later misconstructions around the myth of Malinche that tends to obscure the highly fascinating historical person – an indigenous woman who undertook a decisive part at the time when this was not necessarily common for native women, and would become less so under Spanish rule.
---------
& nbsp;
- For a general introduction, [this AHA site](_URL_2_) by Nancy Fitch is a good start and also helpful for teachers.
It includes a few short primary sources [on Malinche](_URL_1_) which I've drawn on here (with an over the top article title).
- For a more in-depth book, see Camilla Townsend's great "Malintzin's Choices".
-------
*Edit: added images*
| [
"Moctezuma gave lavish gifts of gold to the Spaniards which, rather than placating them, excited their ambitions for plunder. In his letters to King Charles, Cortés claimed to have learned at this point that he was considered by the Aztecs to be either an emissary of the feathered serpent god Quetzalcoatl or Quetza... |
Why do we get hungry sooner after a small, high-calorie meal than after a large, low-calorie meal even if the net caloric content is the same? | Hunger is a physiological response to a range of chemical markers in blood changing, such as depleted blood glucose and reduced blood amino acid content. When you eat, you trigger a number of chemical pathways, such as through stretch receptors in the stomach wall, which stimulate secretion of gastric juice, and G cells activated by food proteins, that secrete gastrin triggering the release of a range of peptides and hormones.
The long story short, stretch receptors will be activated to a greater extent by a larger volume of food, regardless of caloric content, which in turn will trigger the release of greater quantities of huger-suppressing hormones such as Cholecystokinin, which act to stop the hunger reflex from being triggered for a period of time. The presence of more proteins and other chemicals in low-calorie foods will activate more G-cells too, in turn inducing more hormone and peptide release
Hence, the greater volume of food will in effect make you feel 'fuller', even if caloric content was the same, due to the food volume and protein makeup of the food acting to induce greater hormone release
For a good paper on the topic,[ refer to this](_URL_0_) | [
"In the era of foraging for food, hunter-gatherers rarely knew where their next meal would come from. As a result, filling their stomachs up with lots of food was advantageous since food was scarce. Intense consumption of high-energy foods was selected for when the availability of food was low and it was more diffi... |
Why are American spellings of many words different from English spellings? | I can only speak for the Australian experience. There has been some use of US spelling in Australia.
For example the ALP which is the Australian Labor Party. It was spelt with the American spelling of Labour as they believed it showed that they were progressive. Originally they had been proRepublic (still are, but much more so originally) and believed that the British spelling of words should be changed to the US spelling as a symbol of breaking away from the "mother country".
Many Australian newspapers too used US spelling for quite a long time. The reasoning was that dropping the U saved space and saved space was more money since you could fit stories in over the newspaper.
However, this reform hasn't been official. While the ALP uses US spelling for its name it hasn't pushed for reform in schools, at least not in recent years that I am aware of. There also doesn't seem to have been much uptake by the population in regards to US spelling even though they had been exposed to it through the ALP and the media. In more recent years though newspapers have reverted back to the normal spelling of words as apparently the cost savings no longer really apply. | [
"American English is different from British English in terms of spelling (one example being the dropped \"u\" in words such as color/colour), grammar, vocabulary, pronunciation, and slang usage. The differences are not usually a barrier to effective communication between an American English and a British English sp... |
how do software updates like ios11 speed up the phone? | The hardware will determine the maximum performance. How fast a app or the operation system depends on hot the program code is written.
There are multiple ways to write code that do the same thing and it is usually the case. The simplest and fastest way write code often will result in a slow program. If you spend more time on the code you will likely find a faster way to do it that might be more complicate but the program will be faster.
Here is a [BBC video](_URL_0_) that in a simple way explain that that different algoritm can take different time to do the same thin. It it not exactly the same as how speedup of a OS works in most case but is illustrates in a nice way that the the speed of a programs will depend of how it is written.
It is often the case that the program that translate the code to what runs on the hardware (compiler/interpreter) get faster. It takes time to optimize it for a new CPU etc and the engineer that writs it have now had time to make it faster.
There might also be another reason is that for different reason the phone gets slower and slower over time because of how data is stored etc. It might be the case that a
| [
"iOS 9 is a smaller update than iOS 8, requiring 1.3 GB of space, compared to 4.58 GB for iOS 8. Additionally, iOS 9 includes an option to temporarily delete apps to allow the update to install. Once the update has been installed, the apps will be automatically restored. iOS 9 also features \"app thinning\" functio... |
Why do dogs obey our commands? | We've selectively bred them to be good at it. | [
"Working dogs have always learned to obey commands related to the work that they historically performed, such as when a herding dog moves a flock of animals in response to a shepherd's whistled directions, or a hunting dog searching for (or chasing down) quarry or leaving the treed quarry at the hunter's command.\n... |
why are the majority of boundaries between us states perfect straight lines? | Most of these answers make conventional sense, but they don't get to the heart of why this is really true, /u/maphhifi.
Here's the thing: maps differ depending on who draws them, and more importantly, where those people are from. A map that the Haudenosaunee (aka Iroquois) people would have drawn to lay out their territory would look very different than what White Protestants would draw. Generally, when the people who have historically lived in and thrived in one location draw maps, they do so with those considerations in mind: **when locals make maps, they usually try to divide up populations, territory or villages based on culture, economics, politics or language, not simple geography.** Why would they? After all, knowing what village is allied with which tribe, or knowing which town speaks what language or follows which religion, is much more important to everyday life than knowing where a mountain or river is.
Now, look at a map of the world, and count how many countries, provinces, territories and states have borders with straight lines. Notice anything? Yeah: **almost all of those straight-lined borders** are in Africa, the Middle East, Australia, the western and north-western US/Canada. What's the common element here? **These are all nations and provinces that were subject to colonialism and colonization.** And colonialism/colonization, as systems employed by the empires of the world (as well as the US), had one goal: the *extraction of value* from nations, the same way you'd extract value from a mine or farm you own. And if your goal is to extract value instead of show borders between different cultures or towns, you're going to draw that map very differently. More specifically, you're going to draw it with a lot of simple, straight lines so you don't waste time or energy mapping it out or considering what the land is like, who is on it and what they might feel about it.
Probably the worst example of this (and that's saying something, if you've ever read about the tragedy that was the Scramble for Africa) is the [Sykes-Picot Agreement](_URL_0_), which the British and the French formed between themselves to divide up formerly Ottoman territory after World War 1. The map of the area (which encompasses parts of what is now Iran, Iraq, Turkey, Lebanon, Jordan and, most importantly, Syria) was almost entirely **a straight line**, with the Brits taking one half and the French taking the other. That boundary was one of the deciding factors that split up dozens of cultures and people who spoke dozens of languages and dialects, believed different religions, and had radically different cultures and political philosophies. It split communities that were probably better off together, and put communities who were enemies together. If you've ever wondered why Africa seems to have so many civil wars in relation to other continents, *this* is one reason you can trace it back to: cultural conflicts that force opposing interests into one space.
**That** is the real reason why there are so many nations with straight-line borders: because they were almost all colonized nations or territories of a former empire, which usually had really bad consequences.
One of my favourite professors ever in the History department summed this up best: "Any time you see straight lines on a map, you can bet money that the person who drew that map didn't live there." | [
"Because of its unique history, many of the boundaries of the political divisions of the United States were artificially constructed (rather than being permitted to evolve and drawn using natural features of the landscape). Therefore, many U.S. states have straight lines as boundaries, especially in the West. Howev... |
How is there a way to clean radioactive water like the water at the Fukushima plant? | It's not the water itself that's radioactive, it's that it's contaminated with radioactive matter. You can separate that out any which way; filtration or evaporation and so on. _In principle_ it's very easy, but in practice it's much more difficult because of the safety hazards posed by the radiation. | [
"Forty-five tons of highly radioactive water leaked from the apparatus being used to decontaminate the water at the plant. Plant workers attempted to contain the leak, but it was unknown if any of the water escaped into the water table or the ocean.\n",
"This method has been developed by among others, by professo... |
What altitude does sound stop working? | NB This is not a complete answer, but this may be of use to someone who has time to write and research a fuller answer:
The atmosphere doesn't suddenly stop in the same way that - say - the oceans do with a clear boundary between water and air. Instead the atmospheric pressure gets less and less, and the density also decreases as there is a smaller mass of air pressing down on it.
There will be sound waves through the atmosphere, and of course Felix Baumgartner would be able to hear any vibration of his suit.
Baumgartner's exit altitude was 38.9694 kilometres [Source](_URL_0_) | [
"Note that the speed of sound decreases somewhat with altitude, due to lower temperatures found there (typically up to 25 km). At even higher altitudes the temperature starts increasing, with the corresponding increase in the speed of sound.\n",
"As altitude increases through the atmosphere, the first sound waves... |
Why do white shirts glow under U.V. lights? | Washing powder often contains a compound that fluoresces under UV light. This is to make your "whites seem whiter" when outside in the sun. | [
"Fluorescent compounds are often used to enhance the appearance of fabric and paper, causing a \"whitening\" effect. A white surface treated with an optical brightener can emit more visible light than that which shines on it, making it appear brighter. The blue light emitted by the brightener compensates for the di... |
hypnosis | Please do not talk about hypnosis from a Freudian standpoint (ie: subconscious and conscious minds). Hypnosis is a state of selective attention and concentration in which highly suggestible people (10% or so of the population) can exert a lot of control over the processes in their brain using top-down control. For example, have you ever been studying very hard and forgotten how hungry you are for hours? That's your PFC exerting top-down control on the rest of your body, and the same process can be used to convince yourself that you perceive your arms are very light, or you feel/don't feel some sensory information and are being hypnotized.
Usually stage hypnotists are half suggestion, half showman tricks. The performer will use patter talk or some group exercises (magic tricks, for example) to calm everybody down (imagine mimicking spacing out watching TV) and select those individuals that seem to be most affected for further suggestion onstage: usually just turns into befuddling them and making them seem very confused, etc.
You can determine how suggestible you are with measures like the stanford hypnotic suggestibility scale, for instance.
Wiki links!
[Stage Hypnosis wiki](_URL_1_)
[Stanford Scale](_URL_0_) | [
"The earliest definition of hypnosis was given by Braid, who coined the term \"hypnotism\" as an abbreviation for \"neuro-hypnotism\", or nervous sleep, which he contrasted with \"normal\" sleep, and defined as: \"a peculiar condition of the nervous system, induced by a fixed and abstracted attention of the mental ... |
do other mammals (apes, cows, etc.) get high from weed smoke, or trip balls with magic mushrooms? | Elephants seem to deliberately go for fallen, fermented fruit knowing full well from experience the effect it will have. An elephant never forgets it really loves you, mate. Nah, really really, OK, like you know, defnally LOVES you. Who you calling big nose...? | [
"Due to the bioaccumulation of caesium-137, some mushrooms as well as wild animals which eat them, e.g. wild boars hunted in Germany and deer in Austria, may have levels which are not considered safe for human consumption. Mandatory radioactivity testing of sheep in parts of the UK that graze on lands with contamin... |
If elephants had gone extinct before humans came about, and we had never found mammoth remains with soft tissue intact, would we have known that they had trunks through their skeletons alone? | Trunks do leave visible attachment marks for muscles, ligaments, & such on the skull. However, from osteological correlates alone, it would be impossible to infer exactly what the trunk looks like. In what is perhaps a "reverse-application" of this line of reasoning, [trunks can be rejected for sauropod dinosaurs](_URL_1_).
EDIT: [Another discussion of osteological correlates of trunks](_URL_0_), this time applied to the giant rhinoceratid *Paraceratherium*. | [
"The skeleton of an ancient species of elephant has been preserved in the sediment near what was once the edge of a quite small lake revealed by excavations in advance of the Channel Tunnel Rail Link. The skeleton was surrounded by flint tools suggesting it was butchered for its meat by early humans of that era. On... |
Was The Ottoman Empire eager to join WWI against Britain as retribution for the Treaty of Balta Liman in 1838, or were they more weary and only did so at the bequest of their ally Germany? | By the onset of WWI, the Ottoman Empire, despite being a parliamentary monarchy by name, functioned more as a de facto oligarchy, with the men in charge being known as the the [Three Pashas](_URL_0_). It was under the Three Pashas that the Empire entered the [Ottoman-German Alliance](_URL_1_), signed on August 2nd, 1914, which was largely secret until the Empire's entrance into WWI.
However, the nature of the alliance itself stemmed from the necessity of the Ottoman Empire to maintain geopolitical stability abroad so that the newly revolutionary government could consolidate its power domestically, a goal that could only be achieved by allying with a major European Power. Due to the politics of the time, Germany was the Ottoman Empire's best chance.
It could be argued the British seizure of the *Sultan Osman-ı Evvel* and *Reşadiye*, two battleships that the Ottoman Empire had already paid the British Empire in full to build for them, pushed them to officially join up with the Central Powers, espically after the German Empire gifted the *SMS Goeben* and the *SMS Breslau* to the Ottomans, both to prevent them from falling into British hands and also as a show of goodwill to the Porte to help sway them into joining Germany in the ever-escalting WWI (and indeed, these German ships would be part of the attacks on Russian Black Sea ports that would officially bring the empire into WWI). Even then, Sultan Mehmed V still resisted joining WWI, wishing for the Ottoman Empire to maintain neutrality throughout the entirety of the war. | [
"The Anglo-Ottoman Convention was only part of a wider bargaining process and the complexities of the competing European commercial interests in the region prevented its ratification. Russia, France, and Germany (and later Italy) also had been pressing the Ottoman government for railway concessions. Ratification wa... |
why wasps and other insects like it exist | Animals and other lifeforms do not exist "for a reason", and while every lifeform inhabits a niche in it's environment, it does not have to be beneficial to that environment, or to other life in that environment- there is no purpose here.
There is no *requirement* to *contribute*, only life's purpose to perpetuate it's species. Each species of animal exists to perpetuate it's species, and it does so by being successful in it's niche in it's environment.
That said, the niche wasps occupy, the role they perform in their food web, is the same as foxes or killer whales or other photogenic predators. Wasps are carnivores, they eat caterpillars and other such invertebrate prey. Some solitary wasps hunt spiders. Some lay parasitic eggs inside other living things, etc. | [
"Common insects that prey on wasps include praying mantises, dragonflies, centipedes, beetles and moths. In fact, large wasps will even prey on smaller wasps. Spiders will also capture wasps in their webs and eat them. Predatory reptiles and amphibians, such as frogs, lizards, toads, and salamanders see the wasp as... |
why are multiple car dealerships all clumped together next to each other? | You know, I never knew the exact reason behind it until I saw this video: _URL_0_
He explains why you see no gas stations and then 2 next to each other. Video is only 4 minutes long btw. | [
"Used car dealers carry cars from many different manufacturers, while new car dealerships are generally franchises associated with only one manufacturer. Some new car dealerships may carry multiple brands from the same manufacturer. In some locales, dealerships have been consolidated and a single owner may control ... |
how do animal claws start fat at the base and grow pointy? | They are getring used up, meaning theyll get pointy. in the case of a dog, they usually get pointy by the dog just walking, In the case of cats (and I assume many other animals too) the claws grow frome inside out, at the same time as as from back to front. Thats why a cat needs something to claw at, to remove the outmost layer of their claws to expose a new, pointy claw layer underneath | [
"In contrast to nails, claws are typically curved ventrally (downwards in animals) and compressed sideways. They serve a multitude of functionsincluding climbing, digging, and fightingand have undergone numerous adaptive changes in different animal taxa. Claws are pointed at their ends and are composed of two layer... |
why haven't we been able to discover how to craft very old things, such as greek fire? | We can make things like Greek Fire was described. But without knowing what it was we can't be sure what we made was actually the old recipe. It isn't a problem of making the mixture, it is a question of identification of what it was. | [
"The conservation and restoration of Ancient Greek pottery is a sub-section of the broader topic of conservation and restoration of ceramic objects. Ancient Greek pottery is one of the most commonly found types of artifacts from the ancient Greek world. The information learned from vase paintings forms the foundati... |
Why does Croatia's coat of arms have the red and white checkered part? Is there any back story to this or is it just there? | It comes from legends about Red Croatia and White Croatia. Constantine VII Porphyrogenitus, an Eastern Roman Emperor in the 900s talks about inviting the tribe of "White Croatians" to be part of the empire, when they migrated from Bavaria & Krakow, because they were prone to allying with Franks or Turks and that made them an unpredictable military problem that had to be subverted or controlled if they were gonna live on the close side of the Carpathians.
Later around 1300, Red Croatia was invented by a clergyman working under the Archbishopric of Split either to expand Church claims or as a political favor for the Šubić family to justify claims of conquest, expanding the definition of what was "core" Croatian territory to include lands south of the "White Croatians" discussed by Constantine VII Porphyrogenitus.
As centuries passed, all this very shakey and unconfirmable history became national legends everyone took for granted | [
"The coat-of-arms consists of the traditional red and white squares or \"grb\", which simply means 'coat-of-arms'. It has been used to symbolise the Croats for centuries; some speculate that it was derived from Red and White Croatia, historic lands of the Croatian tribe but there is no generally accepted proof for ... |
twin peaks | Erm, what part? There are lots of things about Twin Peaks that are hard to understand. | [
"\"Twin Peaks\" is an American television serial drama created by Lynch and Mark Frost. The series follows the investigation headed by FBI Special Agent Dale Cooper (Kyle MacLachlan), of the murder of a popular teenager and homecoming queen, Laura Palmer (Sheryl Lee). \"Twin Peaks\" features a large ensemble cast, ... |
why do eyes get red when watching tv or a screen for a long time | From straining them. You're focused so you blink less. The same idea can be used when putting pressure on a body part for to long will make it red. The touch is focused on per say. | [
"The red-eye effect, which occurs when flash photos are taken when the pupil is too widely open (so that light from the flash that passes into the eye through the pupil reflects off the fundus at the back of the eyeball), can also be eliminated at this stage.\n",
"Red-eye effect is seen in photographs of children... |
does an older phone battery (less capacity) charge faster than a new phone with brand new battery? and if it’s using a portable battery, will it use less of that portable batteries “juice” to charge than a new phone? | Speed of charge, and total capacity can be very unrelated traits of a battery.
With advances in technology, not only are newer batteries capable of holding more electrical charge in the same physical form factor, but they also are capable of drawing more current without overheating, allowing them to recharge faster than previous iterations.
So, while an older battery might have less capacity, it may take the same amount of time, or in some cases even more time to fully accept the charge required to bring it to capacity, because it doesn't draw as much current from the charger.
Think of a battery as a bucket, and the amount of current it can handle as a hose filling the bucket. With new batteries, the bucket might be the same size, but it has a much wider hose so you can dump more water into the bucket per second and fill it up faster. With an old battery, even if the bucket were physically smaller the hose is very narrow and would take a long time to get enough water inside to fill it up. | [
"older phones tend to draw more battery power in the vicinity of iBeacons, while the newer phones can be more efficient in the same environment. In addition to the time spent by the phone scanning, number of scans and number of beacons in the vicinity are also significant factors for battery drain, as pointed out b... |
why do our bodies produce phlegm when we run/exert ourselves? how did making it harder to breathe help our ancestors? | Well, remember that we aren't so much 'producing' phlegm as we are expelling unwanted things from our body through the medium of phlegm.
Vomiting, for example, isn't intrinsically useful or pleasant, but it's a mechanism to remove harmful things from our body.
| [
"The Phlegmatics draw their name from the ancient four humors theory of the Greek doctor Hippocrates (460-370 BC), who believed certain human moods, emotions and behaviors were caused by body fluids (called \"humors\"): blood, yellow bile, black bile, and phlegm. A phlegmatic person is calm and unemotional. Phlegma... |
when a mosquito bites me, does it take enough blood for the night or does it come back for seconds? | Only females bite, and they bit until they're abdomen is full. From (Mosquito FAQ's)[_URL_0_]:
A female will continue to bite and draw blood until her abdomen is full. If she is interrupted before she is full, she will fly to the next person. After feeding, the mosquito rests for two or three days before laying her eggs, then is ready to bite again."
So you could get bitten more than once if the mosquito decides it's not full after the first bite. | [
"Symptoms typically begin approximately 11 days after an infected mosquito has bitten a person and the parasites can be seen in the blood between 10 – 12 days after infection. The parasite may multiply rapidly resulting in very high parasite densities that may be fatal.\n",
"When mosquitoes bite a person, they do... |
How did the typical rock arrive in my backyard? | Where do you live? The answer to that question will shape the specifics to your backyard. For example in my home state of Michigan most of our geology is related to the movement of glaciers. When the glaciers encroached downwards they blulldozed and pulverized rocks in the path into till. This till is carried southward until the glacier starts recording. The point where the glacier stopped is the terminal moraine and is where lots of our gravel comes from. | [
"The Rocks became established shortly after the colony's formation in 1788. It was known as Tallawoladah by the Cadigal people. The original buildings were first traditional vernacular houses, of wattle and daub, with thatched roofs, and later of local sandstone, from which the area derives its name. From the earli... |
why did america put a term limit in place after such a successful president | Well it's important to realize that the 2 term limit had been enshrined in the American Consciousness since George Washington, so the fact that FDR broke that centuries old precedent (for good reasons, but still) was alarming so there was an impetus to make the unwritten rule a written one.
The whole point of a term limit is to stop popular presidents from holding onto power for too long, as it doesn't take a lot for a FDR to turn into a Caesar or a Napoleon. | [
"Though dismissed by the Constitutional Convention, the concept of term limits for U.S. presidents took hold during the presidencies of George Washington and Thomas Jefferson. As his second term entered its final year in 1796, George Washington was exhausted from years of public service, and his health had begun to... |
why do governments subsidise fossil fuel companies when they are so rich? | Because lobbying. The companies pay people lots of money to convince politicians that it's in their best interests to give taxpayer money to petrochemical companies. | [
"BULLET::::- Fossil fuel companies: Traditional fossil fuel corporations could benefit or lose from stricter global warming regulations. A reduction in the use of fossil fuels could negatively impact fossil fuel corporations. However, the fact that fossil fuel companies are a large source of energy, are also the pr... |
how does a car jack work? | A regular car jack just uses a lever and a hydrolic actuator to lift the car. The force required to lift the car is less when you use a lever. Give me a fulcrum and a lever long enought and I'll move the world. | [
"A jack, screwjack or jackscrew is a mechanical device used as a lifting device to lift heavy loads or to apply great forces. A mechanical jack employs a screw thread for lifting heavy equipment. A hydraulic jack uses hydraulic power. The most common form is a car jack, floor jack or garage jack, which lifts vehicl... |
how do airlines get my bag to my destination? | Inside a modern airport is a massive network of conveyor belts that take the luggage from the check in counter to the area where the baggage handlers are.
As the baggage travels down the belt, pneumatic pushers or gates redirect the bags into different belts that redirect the bag to the proper staging area.
From the staging area, baggage handlers put them into carts that are taken to the airplane and loaded in the belly of the plane either by seat class or by destination.
This is a more modern system.
_URL_0_ | [
"A bag is entered into the baggage handling system when an airline agent, or self check system, assign the luggage a tag with a unique ten digit barcode. Airlines are also incorporating RFID chips into the tags to track bags in real time and to reduce the number of mishandled bags. The BHS will then scan and sort t... |
how does wifi and cell service get slow when too many people are visiting my town of 1500 people? | It's like a pipe. The pipe is sized to supply the normal population, but when there are lots of people, the demand exceeds the flow-rate of the pipe.
Data needs structure to flow along - and it's expensive, so the suppliers don't install more capacity than needed. When lots of people suck on the pipe at the same time it's overwhelmed. | [
"In contrast to development in cities, in rural areas certain people even in 2014 still suffered connection speeds below 256 kbit/s during daytimes and only can achieve speeds of more than 1 Mbit/s during nighttimes.\n",
"The residence hall is an old Sleep hotel. The rent for a small room is $4245–4800 for almost... |
why charging someone more money for insurance based on age isn't considered discrimination. | *Why not base the pricing off of driving history alone?*
Thinks about this for a moment. You just answered your own question.
On their first day behind the wheel, a brand new driver has NO DRIVING HISTORY. Therefore, their premium cost is high. The cost is reduced as they gain more experience, unless their driving history shows the underwriter that they are a bad risk.
This is how actuarial analysis works. Rates are set based on analysis of risk. Without it, there would be no one willing to sell insurance at all. Discrimination is unfair treatment without foundation. People who rob others with weapons get more jail time than those who don't use weapons because experience tells us that they pose more of a threat to society. This isn't discrimination, it's applied logic. | [
"Age discrimination is prevalent because companies have to consider how long older works will stay and the costs of their health insurance accordingly. When companies let these insecurities affect their treatment of older workers- hostile work environment, demotions, lower employment rates-, these older workers who... |
how do two brown haired people create a blonde baby? | Could be that you carry the gene, as does the father.
Genes can be determined using Punnett squares, specific gene combinations are given letters, either capital or lowercase. Capital letters denote a dominant trait that will mask a recessive trait, marked with a lowercase letter.
In this example I’ll say that hair colours brown and blonde are given the letter B.
BB = brown hair
Bb = brown hair but carries the blonde gene
bb = blonde hair
It’s likely that you and your husband both have Bb hair genes:
Bb x Bb
This is worked out in a grid format (usually better written down)
x B b
B BB Bb
b Bb bb
The letters of the parents genes are ‘crossed’ over each other, capital letters always go first because they are the dominant gene.
So this means you’d produce:
25 % BB (brown hair only)
50 % Bb (brown hair carrying blonde gene)
25 % bb (blonde hair)
= 75 % chance of brown haired kid, 25 % chance of blonde.
The probability resets with each child, so it’s possible for you to have more blonde haired kids than brown if the blonde gene happens to strike.
I’m sure other people can explain it better, I’m only using my year 12 biology knowledge but I tried, hope it helps! | [
"One phenotype (brown/blonde) has a dominant brown allele and a recessive blond allele. A person with a brown allele will have brown hair; a person with no brown alleles will be blond. This explains why two brown-haired parents can produce a blond-haired child. However, this can only be possible if both parent are ... |
do cats and dogs 'like' their owners, or is it simply an intrinsic sense of security that draws them to their human companions? | I read somewhere that domestic pets have had the attachment to humans bred into them over 1000's of years. | [
"As a family dog, they make good security dogs and faithful family guardians. They can be very friendly and playful, even in old age. They regard their family as their flock, and will keep their distance until they are sure a stranger is not a threat. When annoyed, they may attack without warning, so a considerable... |
How important is Earth's distance from the sun, for human survival? | You're pretty much asking what the definition is of the [habitable zone](_URL_0_). And yes, astronomers have put a great deal of thought and work into this.
Unfortunately the answer to how far you could move Earth in/out depends heavily on theoretical climate models. The [Kasting](_URL_1_) (1993) model was the standard for a long time. Lately people have switched to using the [Kopparapu](_URL_3_) (2013) models.
But there's a lot of assumptions and uncertainties in the models. With the Earth and Venus as essentially our only two solid data points, we don't have too much to go on. That said, the general answer
(**TLDR**) is probably that liquid water could exist on Earth's surface inward to about 0.9AU and out to 1.5-2AU (the Earth is at 1AU by definition). So there's probably some wiggle room, but I'll emphasize again that these are very vague numbers and we don't know the limits all that well right now.
And yes, astronomers use this to look for planets that are within their star's habitable zone under the assumption that those would be the best places to look for other intelligent life like us that requires liquid water. How common such planets are again is a subject of intense research right now. The numbers change depending on what assumptions you make and how exactly you do your data analysis, but they seem to be settling around saying that 5-60% of stars will have an Earth-sized planet in their habitable zones (e.g. [Petigura](_URL_2_) (2013) or [Dressing & Charbonneau](_URL_4_) (2013)).
That may seem like a wide range to you (and it is), but it still tells us that the Earth is not a one in a million type planet. It seems like at least 1 in 20 stars in the universe has a planet about the right size and temperature to host life, which is amazing!
| [
"BULLET::::- Jeremiah Horrocks: Astronomer who calculated that the distance between Earth and the sun was 59,000,000 miles – though well short of the actual distance of 93,000,000 miles, his estimate was more accurate than any other calculations of his time.\n",
"BULLET::::- The distance of Earth from the Sun is ... |
whats that thing i see when my eyes are closed, while i press the top of my eyes side to side? | I've never heard of what you described; most people see random patters of colors kind of like looking through a kaleidoscope....It's called an "entoptic phenomenon," meaning that it originates from the eyeball. When you apply pressure to the eyeball, you also put pressure on the retina, which is basically the part of the back of the eye that turns light waves into brain waves.
When you apply pressure to the retina, two things happen....you deform the retina slightly and essentially make the photo receptors (specialized cells that pick up light and send info to the brain) fire manually. It may also affect the cells' ability to pick up oxygen from the blood. The retina has one of the highest metabolic rates of any tissue in the body, and if you disrupt its oxygen supply for even a fraction of a second, they may start abnormal firing activity and sending random signals to the brain, leading you "see" random light and color patterns. | [
"Bell's phenomenon (also known as the palpebral oculogyric reflex) is a medical sign that allows observers to notice an upward and outward movement of the eye, when an attempt is made to close the eyes. The upward movement of the eye is present in the majority of the population, and is a defensive mechanism. The ph... |
What is the oldest, continuous land border in the world? | Do you want one that has been fixed in place for the longest time?
If so, the Swedish-Norwegian border (which remained even when the countries were in a Union 1814-1905) has been the same since 1660.
Portugal has had the same borders since about 1300, but the states on the other side of the border has gone from Catile to Spain. Spain and Portugal were also in a Union 1580 to 1640. | [
"The oldest known boundary stone in China is from Jiangsu Province. Dating from 12 A.D., it bears the inscription \"the sea area from Jiaozhou Bay to the east of Guixan county belongs to Langya Shire and the waters from the south of Guixan county to the east of the estuary of Guanhe River belongs to Donghai Shire.\... |
how do statistical websites count enormous numbers such as the birth and death count, or the population of the earth, or even money spent on illegal drugs? | These are estimates based off some formula. Lots of governments and organizations collect vast amounts of demographic data and publish it freely, all you need to do is a look at a few numbers for whatever you are interested in, devise a formula, and easy enough.
For example, If I drink 1 liter of water a day, After a year I drink 365 liters. Simple, 1 liter per day x 365 days.
None of these are particularly much more complicated, though they probably are a bit more complicated formula, the idea remains the same.
FYI that site also gives their data sources | [
"The measures of central tendency, mean, median, and mode, should be considered when assessing a population pyramid. since the data is not completely accurate. For example, the average age could be used to determine the type of population in a particular region. A population with an average age of 15 would have a y... |
how can bill clinton almost get impeached for lying to congress, yet hayden and other intelligence agency officials do so regularly and nothing happens? | Impeachment is NOT the removal of office, it simply means to formally bring charges against an official.
Clinton was impeached. | [
"Since Ken Starr had already completed an extensive investigation, the House Judiciary Committee conducted no investigations of its own into Clinton's alleged wrongdoing, and it held no serious impeachment-related hearings before the 1998 midterm elections. Nevertheless, impeachment was one of the major issues in t... |
how do you really know sites like duckduckgo aren't stealing your info and selling it? | You can always see what data websites are asking for from your browser (in most browsers you can press F12 and go to the "network" tab). If you do that for [DuckDuckGo](_URL_0_) and compare it to [Google](_URL_1_) you can see that Google stores all kinds of unique identifiers in a cookie while DuckDuckGo doesn't.
While you still can't be sure that DuckDuckGo aren't recording the searches people do, you can be sure they're not using any unique tracking ID on you and so would lose your search record every time your IP address changed. | [
"DuckDuckGo, founded in 2008, is known for being privacy focused and not tracking its users. DuckDuckGo does not collect or share any personal information of users, such as IP addresses or cookies, which other search engines usually do log and keep for some time. It also does not have spam, and protects user privac... |
why aren't planets or the moon declared property of a country? | International treaties barring the claiming of any body outside of the Earth by countries.
Plus you can declare as much as you want it doesn't make it so. | [
"Independent sovereign nations claim the planet's entire land surface, except for some parts of Antarctica, a few land parcels along the Danube river's western bank, and the unclaimed area of Bir Tawil between Egypt and Sudan. , there are 193 sovereign states that are member states of the United Nations, plus two o... |
who were the first to harness the power of advertising? who figured out that concept? | Animals use advertising. Big feathers, bright colors, songs, dances.
"I've got the best product! Have sex with me"
It's as old as time | [
"The history of advertising can be traced to ancient civilizations. It became a major force in capitalist economies in the mid-19th century, based primarily on newspapers and magazines. In the 20th century, advertising grew rapidly with new technologies such as direct mail, radio, television, the internet and mobil... |
Why do young children cry at bedtime? | Remember that the idea of having babies and small children sleep in a separate room - much less a separate bed - from his or her parents is an incredibly recent invention in terms of human evolution, and it's not a universal invention either. Babies didn't evolve to cry when they're being put to bed; they evolved to cry when they're separated from their parents. | [
"BULLET::::- Promotes peaceful sleep: Infants who co-sleep were found to rarely cry during the night compared to infants who slept in a separate room, who startled throughout the night and spent four times more minutes crying than co-sleeping infants.\n",
"Crying in infants is associated with high stress levels a... |
- how do so many sportstars, actors, etc. that make millions of dollars end up in debts? | Because they, like many others in our society, spend more than they make. Yes, they make a lot. They also spend > a lot. | [
"Scores of movie notables spent their last years here, so have far less famous people from behind the scenes of the industry. Those with money paid their own way, while others, who had no money, paid nothing. Fees are based solely on the \"ability to pay.\"\n",
"Basketball Hall of Famer Magic Johnson is an exampl... |
could memory loss make you "forget" you have depression, or any other mental illness? | A treatment for severe depression is electro-convulsive therapy (ECT), where you run an electrical voltage through the brain. This causes memory loss. It's the most effective treatment for depression we know of. It's possible that memory loss facilitates the therapeutic effects. The patients don't forget about their illness, but they may forget trauma that contributed to their illness. | [
"Some mental illnesses, including depression and psychosis, may produce symptoms that must be differentiated from both delirium and dementia. Therefore, any dementia evaluation should include a depression screening such as the Neuropsychiatric Inventory or the Geriatric Depression Scale. Physicians used to think th... |
Why did the germans choose Verdun in WW1 as one of their main targets ? | At a basic level, Verdun was intended to bleed France's armies. Falkenhayn, the commanding German officer, hoped to capture a number of French positions, forcing the French to counter attack to retake them, leaving them open to bombardment from German artillery positions. Falkenhayn hoped to recreate the devastation wrought on the French forces that the German artillery had inflicted during a series of battles in the Champagne region the year before.
The initial stages of the battle went well, German artillery saturated the forward lines and French positions were overrun. The greatest of Verdun's defensive fortresses, Douaumont, was captured by a single German sergeant who bluffed the few defenders into surrendering. The French defenders in the region panicked when news of this spread and it seemed as though a retreat was imminent. However, a French officer named Phillipe Petain was given command of the situation and swiftly turned things around. Coordinating the artillery, Petain brought heavy shelling down on the attacking German forces, doing exactly what Falkenhayn had planned to do to the French. Petain also organised a continuous line of supply to keep his artillery well stocked with shells and ammunition for his infantry. What eventuated was a series of attacks and counter-attacks that ultimately resulted in very little being achieved but at the cost of hundreds of thousands of lives. The offensive began in February, 1916 and by May, more then 200,000 German and French soldiers had become casualties. This casualty rate was particularly troubling for the Germans. While the French rotated their units out of the lines and replaced them with fresh ones, the German units were kept in the line and suffered continuously. The continued back and forth continued until December of 1916 when hostilities in the sector finally subsided thanks in part to the Battle of the Somme which required Germany to divert forces to repelling the British offensive. That said, by the end of the German offensive the French had only a single fresh brigade in reserve so had the hostilities continued, who knows what would have happened.
As to why the battle was such a significant event, I would argue that it is because it was so damned horrific. Even by WW1 standards, the horror that the men faced at Verdun was extreme. Flamethrowers were used for the first time as was phosgene gas, the artillery barrages were continuous and absolutely massive and the casualty rates are among the worst suffered. It also became a symbol of French resistance. The French armies had largely been humiliated and on the backfoot until Verdun and their victories there, no matter how small or costly, symbolised their devotion to resisting German aggression. Verdun did do enormous damage to the French forces. It saw the real beginnings of discontent in the French armies which would eventually lead to outright mutiny in some areas.
Source:
1914-1918: The History of the First World War by David Stevenson
The First World War by John Keegan | [
"The German attacking forces were not able to enter the city of Verdun itself and by December 1916 had been forced back beyond the original French trench lines of February. The sector again became a relatively inactive one as the allied focus shifted to the Somme and the Germans adopted a defensive stance. While ge... |
Why haven't the great muslim empires been able to regain their former glory? | Not to pick on you specifically, but there have been a lot of this sort of a question recently.
This is not a well-phrased question.
If you want really good answers from good historians, you need to frame your question positively, ie. "Why did X happen?" Asking why something didn't happen can only generate vague answers at best, as it runs into the [*post hoc*](_URL_0_) problem even harder than usual empirical study.
Historians do not know what outcome events that did not happen would have had. This, beyond all else, is the most obvious lesson taught by deep historical study.
So, try to look at it in a more positive sense: Why did the predominantly Muslim areas of Africa and the Middle East form into the states, societies, and cultures they did? This question, though complicated, might actually have a valid answer. | [
"The Muslim conquests brought about the collapse of the Sassanid Empire and a great territorial loss for the Byzantine Empire. The reasons for the Muslim success are hard to reconstruct in hindsight, primarily because only fragmentary sources from the period have survived. Fred McGraw Donner suggests that formation... |
During heavy exertion, such as lifting, why do we close our airways? | I can offer a little bit of information on this, but not the complete picture. We don't really need to breathe when we lift or go through quick, heavy exertions. Weightlifting is almost purely an anaerobic exercise (my physio syllabus actually says its 100% anaerobic which makes sense). Oxidative phosphorylation practically never kicks in, because it takes about 2-3 minutes of exercise before your body switches over from phosphocreatine and glycolysis to aerobic methods.
Now for the hypothetical portion of it. I think it provides some stability to the body if you close your airway when you lift. If you breathe, you use your diaphragm which really prevents you from keeping your core tight. Loose core muscles leads to less stability, especially on heavy, heavy exercises. | [
"During heavy breathing as in exertion, a large number of accessory muscles in the neck and abdomen are recruited, that during exhalation pull the ribcage down, decreasing the volume of the thoracic cavity. The FRC is now decreased, but since the lungs cannot be emptied completely there is still about a litre of re... |
In theory, could it be possible for there to be a genetic mutation that stops genetic mutations? | It is possible to get mutations in the DNA polymerase or any of the many proteins involved in DNA repair that would decrease the mutation rate. In fact many of the commercial DNA polymerases used in [PCR] (_URL_0_) are enginered to have very low mutation rates in the PCR environment. However, it is impossible to make DNA replication perfect *forever*. Because of how similar the nucleotides are, it is nearly impossible to have any kind of reaction that can differentiate between them 100% of the time. The best that can be done is to make the mistake rate very very small so that it does not occur often. | [
"As with all genetic disorders, it is of course also possible for a human to acquire it spontaneously through mutation, rather than inheriting it, because of a new mutation in one of their parents' gametes. Spontaneous mutations account for about 33% of all cases of haemophilia A. About 30% of cases of haemophilia ... |
Are there any examples of cross breeding animal species with very similar genomes ie those with recent evolutionary divergence? | Male Donkey + Female Horse = [Mule](_URL_1_)
Male Horse + Female Donkey = [Hinny](_URL_2_)
Male Lion + Female Tiger = [Liger](_URL_3_)
Male Tiger + Female Lion = [Tiglon](_URL_0_)
There may be others.
I am unaware of cross breeds done that are further separated than these animals.
In most cases the result of these mixes are infertile.
> Mules and hinnies have 63 chromosomes, a mixture of the horse's 64 and the donkey's 62. The different structure and number usually prevents the chromosomes from pairing up properly and creating successful embryos, rendering most mules infertile. (from cite above on mules)
| [
"A taxonomist decides whether to recognize a subspecies or not. A common criterion for recognizing two distinct populations as subspecies rather than full species is the ability of them to interbreed without a fitness penalty. In the wild, subspecies do not interbreed due to geographic isolation or sexual selection... |
Medieval Europe experts, how do you feel about Terry Jones' series "Medieval Lives?" | Personally I can't give an opinion, but my medieval Prof (who's a genius, if a little insane) quite likes them, only thing he's considered showing us. | [
"Terry Jones' Medieval Lives is a 2004 television documentary series produced for the BBC. Written and hosted by Terry Jones, each half-hour episode examines a particular Medieval personality, with the intent of separating myth from reality.\n",
"Jones explained his motivation for making this series in the articl... |
why is some food "aged" and still edible while others are rotten and tossed out? | Rotten food is an uncontrolled explosion of microorganism activity, which is almost always going to produce toxins or at least make the food entirely unpleasant.
Aging food is a more controlled process. Conditions such as temperature, humidity, salinity, etc are tuned to allow some bacteria, yeasts, etc to grow and to inhibit others. Somethings are fermented, because we want yeast to turn sugar into alcohol, or other things are aged to become super dry so nothing can grow on it. | [
"Eating deteriorated food could not be considered safe due to mycotoxins or microbial wastes. Some pathogenic bacteria, such as \"Clostridium perfringens\" and \"Bacillus cereus\", are capable of causing spoilage.\n",
"Many of the items, such as kindling and arrows, degrade over time and ultimately break, making ... |
what exactly causes paranoia? | Paranoia and Panic Attacks are reactions to stress or unbalanced brain chemistry.
Essentially your body is reacting to stress like it did when our ancestors were living in trees and caves. You get a dump of adrenalin and other hormones to help you focus and discern danger. With no physical danger, those chemicals start your mind racing and you're trapped thinking about that guy who gave you the stink eye at the mall and rehashing every conversation blunder you've ever made. | [
"Paranoia is a belief system heavily influenced by fear. This extreme fear mostly becomes so strong that it leads to delusion or irrationality. The paranoid thought usually consists of someone or something plotting against him or her. Paranoia can be caused by simple fears, exposure to/experience of trauma, etc. Th... |
why is there an android vs ios "feud" among consumers. | The same reason there's a feud between XBox & Playstation gamers or people that drive Fords and Chevrolets or Team Edward claims superiority over Team Jacob in the Twilight fandom.
People are tribal & insecure. They want to be convinced that they made the right choice and that the "other side" is wrong so that they can feel better about themselves. | [
"BULLET::::- Complaint opened in 2015 that the dominance of the Android operating system was abused to make it difficult for competing third-party apps and search engines to be pre-installed on mobile phones. (See European Union vs. Google.)\n",
"Android has suffered from \"fragmentation\", a situation where the ... |
In 1600, would a 'citizen' of the Holy Roman Empire identity themselves as such? Would they even know they were one? Or was their view much more local? | Citizenship in 1600 Germany was awarded by the Cities which derived [city rights from the Kaiser](_URL_0_) or the lord of the land (bishop, prince etc).
Each new citizen had to make a Bürgereid, a Citizen's Oath, and repeat it every the "swear day" (Schwurtag). Now, the wording was different from town to town - Some would mention God, some the Kaiser, some only the local nobility or the only the city council. But in general the citizens were only the elite of a city as it came with a tax and required ownership of land inside of the city. In 1600 most city dwellers weren't citizens.
Source: Die Huldigung der Untertanen by André Holestein
Now: A citizen was well aware he was a citizen in the Roman Empire. In the Geschichtsklitterung novel by Fischart (1575) a lady is said to be "so slovenly she wouldn't care if the Roman Empire collapsed tomorrow". In the Mother Courage novel (1669) by Grimmelshausen the titular character is a Bohemian citizen speaking both German and Czech. Once her city is burned in the 30 years war she pretends she's a boy who doesn't know any German to pass for a Czech from the underclass and because "the Bohemians are known throughout the Empire for their cookery and their horsemanship". Indeed she makes it to a soldier and a cook. | [
"Before 1806, when general citizenship was largely nonexistent in the Holy Roman Empire, its inhabitants were subject to varying estate regulations. In different ways from one territory of the empire to another, these regulations classified inhabitants into different groups, such as dynasts, members of the court en... |
How do we know that the Earth's atmosphere used to contain more oxygen than nitrogen in the past? | So first off, Earth's atmosphere never contained more oxygen than nitrogen. The highest the oxygen fraction ever reached was 35% during the Carboniferous period some 300 million year ago. [Here's a history](_URL_0_) of oxygen concentration over time.
Now, how do we know that? Largely through proxies of other elements in the crust. More specifically:
- We know that really ancient (2.4 billion years ago+) atmosphere lacked oxygen based on sulfur isotopes in old sedimentary minerals. The only way we know to produce mass-independent fractionated (MIF) isotopes of sulfur is through sulfur dioxide's interaction with ultraviolet light in an oxygen-free environment. The MIF isotopes of sulfur suddenly disappear about 2.4 billion years ago, indicating that oxygen started appearing in the atmosphere around this time.
- [Banded iron formations](_URL_2_) also give us a good handle on oxygen concentration. Free oxygen combines with iron dissolved in ocean water to form iron oxide, which is insoluble in water, sinks to the bottom of the ocean, and eventually creates rock. We see banding structures as oxygen concentration seems to have repeatedly risen and fallen some 2 billion years ago. They also reappear some 650 million years ago, about the time we suspect that [Snowball Earth](_URL_1_) may have occurred and the oceans briefly became oxygen-poor again.
- Lots of other elements can indicate oxygen levels depending whether they're found in their oxide form. Manganese deposits can also be indicator of atmospheric oxygen, since they should should quickly combine into manganese oxide and precipitate out of the ocean if enough atmospheric oxygen is present. Similarly, chromium, molybdenum, copper, zinc, phosphorus, etc. all behave like this.
- Most recently, we know that oxygen levels spiked during the Carboniferous period because of carbon isotopes in plant fossils. Plants grown in high oxygen environments tend to preferentially take the 13C isotope of carbon from the air, and this is preserved in the fossil record.
For a lot more technical detail, [this PDF](_URL_3_) provides a nice overview. | [
"The atmosphere of the early Earth is not well understood. Most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and was lacking in free oxygen. There is, however, evidence that an oxygen-rich atmosphere existed since the early Archean.\n",
"At the time o... |
Why are women less likely to become scientists? | I'll let HonestAbeRinkin write out a more complete answer, but it comes down to a few things:
1. Sexism.
2. A tradeoff between having babies and pursuing a scientific career.
3. Cultural attitudes about the manliness or ungirliness of certain sciences.
All of these are changing for the better, as is the representation of females in science.
Also, in the physics department where I work, the only person important enough to be on Wikipedia is a woman. | [
"For women who are pursuing STEM major careers, these individuals often face gender disparities in the work field, especially in regards to science and engineering. It has become more common for women to pursue undergraduate degrees in science, but are continuously discredited in salary rates and higher ranking pos... |
how do slow songs like lullabies induce sleep? | Music promotes overall arousal or relaxation in listeners, with heart rate being only one factor among many that music influences. When a music listener's brain registers the tempo of a song, his brain sends signals to the body that cause breathing to either accelerate or decelerate, matching the tempo of the music. At the same time, the listener's heart rate races or slows accordingly. The listener's brain and body pick up on the tempo and rhythm of the music, and the heart beats to match them.
Read more: Why Does Music Affect Your Heart Rate? | _URL_1_ _URL_0_
| [
"Rhythmically, there are shared patterns. Lullabies are usually in triple meter or 6/8 time, giving them a \"characteristic swinging or rocking motion.\" This mimics the movement a baby experiences in the womb as a mother moves. In addition, infants' preference for rhythm shares a strong connection with what they h... |
who owned ancient artifacts before they were in museums, assuming most museums were built in the 20th century? | You should pose this question to /r/archeology as the folks in that subreddit are very helpful and friendly.
| [
"Early museums began as the private collections of wealthy individuals, families or institutions of art and rare or curious natural objects and artifacts. These were often displayed in so-called wonder rooms or cabinets of curiosities. One of the oldest museums known is Ennigaldi-Nanna's museum, built by Princess E... |
Are organisms that use non-XY sex determination systems "male" and "female" in the same sense as mammals? | We use the female designation to tell which animal has the ova and which ones don't. Usually this is how we go about it regardless of the chromosome structure. ZZ birds are designated as male since they do not have ovaries. Likewise, XX humans are designated female because they carry the ovary. Animals that carry both eggs and a fertilizing agent (usually sperm) are designated as hermaphroditic.
That's not to say all animals follow this scheme. Fish are the biggest violators of the traditional XX and XY scheme because many fish, especially among the tropical fish, tend to be sequential hermaphrodites meaning they change sex with time. So using a chromosome structure to dictate male or female is moot if they are going to switch sex down the road.
Tl;Dr A female is the gender of the organism that carries the ova, the male is one who does not, and in hermaphrodites, it can be bi-gendered or sequentially gendered. Chromosomes patterns are merely correlated with gender when it comes to animal sexing. | [
"Not all species share a common sex-determination system. In most animals, including humans, sex is determined genetically, but in some species it can be determined due to social, environmental, or other factors. For example, \"Cymothoa exigua\" changes sex depending on the number of females present in the vicinity... |
why do countries import and export the same product, like crude oil, or chicken? | Different types of chicken, different flavours of crude plus individual companies with different trade agreements with other companies and countries | [
"An export in international trade is a good or service produced in one country that is bought by someone in another country. The sum of the exports of the states is significantly lower than the value of the United States's total exports. The difference results from goods originating from states of origin, returned ... |
in the world of trading stocks, what is margin buying power? | Buying on margin is essentially taking out a loan to buy securities, using your already owned securities as collateral.
Say you own a bunch of stocks worth $100,000. Your broker might lend you up to $70,000 to buy other stocks using your $100K as collateral. If the stock values drop to a certain level though you risk having a margin call in which case they'll take and sell some or all of your $100K to pay back the loan. | [
"This trading or \"betting with positive edge\" method involves a [[Money management|risk management]] component that uses three elements: number of shares or [[Futures contracts|futures]] held, the current market price, and current market [[Volatility (finance)|volatility]]. An initial risk rule determines positio... |
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