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Is it possible that a virus could act as a vaccine for several other worse viruses? | as arumbar already pointed out, this is exactly the case with smallpox, modern small pox vaccinations actually contain the related virus *vaccinia* (smallpox is called *variola*). "Vaccination" actually comes from "vaccinia", natch.
This is less useful for virus that are more topologically varied, such as the flu virus; you might be vaccinated for one type of flu, and a very closely related variant might already be different enough that the vaccination doesn't protect you.
edit: as for the "intentional tribal reservoir" idea you posit, I don't really know much about tribal peoples and their knowledge of disease, but I don't think any stone-age peoples were capable of such forward thought given their limited knowledge base | [
"A vaccine against a particular virus is relatively easy to create. The virus is foreign to the body, and therefore expresses antigens that the immune system can recognize. Furthermore, viruses usually only provide a few viable variants. By contrast, developing vaccines for viruses that mutate constantly such as in... |
according to einstein's theory of relativity, events that occur at the same time for one observer could occur at different times for another. what does this mean? what are some eli5 examples? | If you want to do further research on this, a good specific search phrase is the relativity of simultaneity.
A common example is called the train and platform.
Imagine there is a box car, with open sides, and a shuttered lantern in the middle. There's a guy standing by the lantern, ready to open it.
The train is moving along the tracks, approaching a platform, where another guy is standing.
As the train car passes the guy on the platform, the guy in the train opens the shutters on the lamp. For the guy in the train car, the lamp, and the edges of the train car, are all stationary objects. Since the lamp is in the middle of the train car, it takes the light the same amount of time to reach the front wall as it takes to reach the back wall, since they are equally distant.
To the guy on the platform, the rear wall of the train is approaching where the light came from, and the front wall is receding from where the light came from, so the light will reach the rear wall before it reaches the front wall. It has a shorter distance to travel one way than the other.
This wouldn't be true if the light moving 'backwards' was slowed down by being emitted from a train moving forwards, but we can experimentally verify this is not the case, both observers would see both beams of light moving at the same speed, so the only alternative is that what is simultaneous for the guy in the train is not for the guy on the platform. | [
"According to Einstein's special theory of relativity, it is impossible to say in an \"absolute\" sense that two distinct events occur at the same time if those events are separated in space. If one reference frame assigns precisely the same time to two events that are at different points in space, a reference fram... |
How does consuming caffeine compare to absorbing it through your skin? | We can change this question to "How does swallowing Drug X compare to absorbing it through your skin?"
First of all, it's important to remember that our skin is pretty amazing at keeping things out. It is not a great absorber of substances, period. Most ointments and creams that you apply will find it very difficult to get to the dermis (the deep part of your skin), and extremely difficult to go deeper than that to big blood vessels.
Now, most drugs have an ideal method of delivery. Some are absorbed through your gut, some by injection and some by breathing them in. Caffeine is at the end of the day, another drug, that is absorbed reasonably well through your gut.
So going back to your question, studies showed that about 2micrograms of caffein per square cm of your skin is absorbed an hour at best. Coffee's caffeine contents vary, from 100mg to 300mg in your triple venti coffee. Even if we go for 100mg, this is 50,000cm^2 of skin that we would need for the caffeine to get to the *first layer* of skin. In 1 hour! And we only have 1900cm^2 of skin in the first place! And, only a tiny amount of coffee is abosrobed in the first place.
So, if you just rub the same amount as what you'd drink, nothing would happen. Absolutely nothing except perhaps causing some irritation of the skin. | [
"Absorption through the skin is increased when lotions are applied and then covered with an occlusive layer, when they are applied to large areas of the body, or when they are applied to damaged or broken skin.\n",
"Caffeine from coffee or other beverages is absorbed by the small intestine within 45 minutes of in... |
who writes the stuff that goes in fortune cookies? | Apparently, the [CFO of the company who manufactures the fortune cookies](_URL_0_). Maybe that's why they so often refer to wealth? | [
"A fortune cookie is a crisp and sugary cookie usually made from flour, sugar, vanilla, and sesame seed oil with a piece of paper inside, a \"fortune\", on which is an aphorism, or a vague prophecy. The message inside may also include a Chinese phrase with translation and/or a list of lucky numbers used by some as ... |
If a curveball was thrown in an obstacle-free, zero-gravity environment, would it follow a spiral pattern or return to the pitcher? If it's a spiral - does it curve inwards or outwards? | The curve of the ball is dependant on the resistance of the air to the spinning motion. All pitches take advantage of such resistance. A ball will even rise once it catches the air just right. A spinning ball in an space with air but without gravity would move in a curve until the air resistance stopped the spin. In a gravity free space the spin is independant of the angle of motion of the ball so spin would have no effect on trajectory. | [
"On the other hand, a curveball, thrown with topspin, creates a higher pressure zone on top of the ball, which deflects the ball downward in flight. Instead of counteracting gravity, the curveball adds additional downward force, thereby gives the ball an exaggerated drop in flight.\n",
"Over the distance from the... |
How were voters made aware of U.S. presidential candidates before radio and television? | I've [written about this before](_URL_0_), but essentially, newspapers both shaped and were shaped by early political parties, and a national network of subsidized distribution through the postal service meant that most towns had access to multiple newspaper titles. To quote from that earlier answer:
> Anyhow, in the years after Freneau and Fenno, partisans would often organize them around newspapers, and printing presses were some of the first things to arrive in new towns. The way that the system generally worked was that each party might find an enterprising local person to serve as editor of the paper, and a skilled printer to actually produce the paper (printers themselves, being ink-stained wretches who often had deformities related to the physical difficulties of printing, were not often party leaders). The editor/printer would print political news, party platforms, and write screeds against his opposing editor, and they would often be rewarded (if the party was in power) with patronage, in the form of postmasterships and printing contracts. Newspapers also printed party ballots, which was crucial in an era before standardized ballots provided by the government. | [
"The increase of the media at these conventions originally led to a growth in the public's interest in elections. Voter turnout in the primaries increased from less than five million voters in 1948 to around thirteen million in 1952. By broadcasting the conventions on the television, people were more connected to t... |
Sex positions names in the last centuries (1200-1800) | Let me offer a small window into the names of sex positions as one guide called them c. 1500.
In the summer of 1524, an artist named Giulio Romano was working on painting saints in the Vatican. In the spirit of bored workers and doodling schoolchildren everywhere, he decided to dash off 16 sketches of obscene character to amuse his friends. In the words of one contemporary, these sketches "dealt with the various attitudes and postures in which lewd men have intercourse with lewd women." Had this been a century beforehand, a good number of rich and powerful nobles would have had a laugh at the sketches, passed them around to their friends, and then they would have disappeared forever. However, along with the printing press, another German technology with great and terrible potential had filtered down into Italy—engraving.
Inspired by the printing press, artists looking for mass reproduction had turned to carving a block of wood, filling the gaps with ink, and then pressing them on paper, resulting in what was called a 'woodblock print.' These woodblocks were capable of several thousand impressions, and were often colored in with watercolors or by hand. In fact, woodblocks were most often used to create playing cards. The downside to using wood was that the images would begin to fade and wear down after a few thousand impressions. Additionally, like with the printing press, demand very quickly outstripped supply, and an alternative method was needed. This alternative was found in copper, first by goldsmiths (who had a right to metal engraving under feudal law), and then by painters, the most famous and influential of which was Albrecht Dürer. Dürer, much like Aretino, realized that the developing middle class could not yet afford to own beautiful paintings or decorations, but they could afford copper engravings, which could be sold by the hundreds of thousands.
Although Dürer was the first to realize the potential profits and fame, he was not the only one. One Marcantonio Raimondi (who drew our picture of Aretino above) , from Bologna, stole Dürer's engraving technique and used it to print a few hundred copies of Romano's dirty pictures, arguing in a letter to his friend that "they will circulate, and [you and I] will at the same time become both rich and famous." And they did. However, Raimondi perhaps sold the engravings far too eagerly and recklessly, to every possible customer, which, even in Rome, led to his arrest and imprisonment by Clement VI. In a lucky break, his friend Pietro Aretino managed to secure his release. The thankful Raimondi showed Aretino the engravings that he had been imprisoned for, and Aretino declared that he was inspired by them, and wrote 16 sonnets to go along with them, dedicating them in a letter to “all hypocrites [such as Giberti], for I am all out of patience with their scurvy strictures and their villainous judgment and that dirty custom that forbids the eyes to see what most delights them. What harm is there to see a man possess a woman? Are the beasts freer than we?” The pairing of the engravings with Aretino’s dirty poems created something really unique—perhaps the first Playboy Magazine in all of history.
The combined work of these three men was a work called *I Modi* and it was explosive in its success, crossing Europe like wildfire and being translated and spewed into new editions for centuries. The origanls are largely lost, the British Library has the only recorded surviving ones from the second edition--you can see a picture here of the remainders:_URL_0_
However in 1602, one Agostino Carracci made copies of the originals for a French translation. These editions that he captioned with the names of various Greek and Roman figures and god(desse)s are the versions that come down to us today. Their subtitles would go on to describe some sexual positions for the next century or so. For example, the position that we call wheelbarrow was termed the Bacchanal style in later pornography. Another, the Herculean described what we might call a standing position. I've compiled several of these in this imgur album [super NSFW]
_URL_1_ | [
"There is a persistent urban legend, repeated by the now defunct UK newspaper the \"Sunday Correspondent\", that ascribes sexually suggestive names – such as Master Bates, Seaman Staines, and Roger (meaning \"have sex with\") the Cabin Boy – to \"Captain Pugwash\"'s characters, and indicating that the captain's nam... |
why are some roofs shaped like this ? (northern france so not a snow area) | Might want to check that link again. I'm not seeing any roof there. It just shows random stuff every time it loads. | [
"Flat roofs exist all over the world and each area has its own tradition or preference for materials used. In warmer climates, where there is less rainfall and freezing is unlikely to occur, many flat roofs are simply built of masonry or concrete and this is good at keeping out the heat of the sun and cheap and eas... |
what is a brokered convention and what would that mean for the u.s. democratic primary? | In simplest terms, the nominees do not have a majority to become the "Democratic Nominee."
A convention occurs where negotiations go on behind the scenes to try to get other nominees to drop out while delegates continue to vote and revote until a majority occurs. For instance, perhaps one nominee will promise another nominee the VP spot or a cabinet spot.
What does this mean? It means that whomever is picked in the end as the nominee for the Democratic Party does not have a united party behind them. If that person does not have a united party behind them, then most likely the other major party will win the election (because a lot of people will vote for someone else - like an independent).
So, if the priority is getting Trump out of the White House, the last thing the Democratic Party wants is a Brokered Convention. | [
"In United States politics, a brokered convention (sometimes referred to as an open convention and closely related to a contested convention) can occur during a presidential election when a political party fails to choose a nominee on the first round of delegate voting at the party's nominating convention.\n",
"N... |
What is rocket fuel and how do we get it? | You’re not entirely wrong on the gasoline thing, believe it or not. IIRC, the first stage of the Saturn V was powered by a mixture of liquid oxygen (LOX) and kerosene. You’re also right about ice: you can electrolyse water into its base components, hydrogen and oxygen, and use that as fuel. Granted it’s not necessarily as simple as I describe it but that’s the gist of it. If you really feel like learning about rocket fuel, I suggest reading Ignition! An Informal History of Liquid Rocket Propellants by John Drury Clark. You can find the entire text online for free (can’t give it to you now, mobile).
EDIT: [Here’s the book for you](_URL_0_) | [
"The liquid-fuel rocket is a rocket with an engine that uses propellants in liquid form. On March 16, 1926 in Auburn, Massachusetts, Dr. Robert H. Goddard, the \"father of modern rocketry\", launched the first liquid-fueled rocket in history, which used liquid oxygen and gasoline as propellants.\n",
"Rocket fuel ... |
Is it easier to slow a car by holding the brakes, or by pressing and releasing them? | a few things.
firstly you're not 'creating more inertia'. inertia is a property of all bodies with mass which is just a consequence of Newton's Laws: a body will maintain its motion unless acted upon by a force, and the force required to achieve a certain change in velocity (i.e. acceleration = change in velocity / time) is F = mass * acceleration.
If you want to change the velocity of a car from v to zero you will have to provide a certain force for a certain time. It does not matter how you break up that time, everything is linear. So no, in that sense there is no difference between breaking all at once or breaking in bits.
I think your question is inspired by the fact that if you're driving an old car without anti-lock breaks and going very fast or on slippery ground it makes sense to 'pulse' the break pedal to stop in the shortest possible time. (Anti-lock breaks automate that process.)
However, that has its origin in an entirely different phenomenon. If you have an object lying on a surface then you need to exert some minimum force F = mu_s w to get it moving. w is just the object's weight, and mu_s is the *coefficient of static friction*. The bigger it is the harder the object is to move (so for example the coefficient of static friction of a tire on road is quite high, but of roller scates on ice is very small. It varies for each combination of materials.)
On the other hand, if an object is already moving and you just want to keep it moving at the same velocity you will have to apply a force F = mu_k w. (so for example you're shoving a box and you want to move it across the room.) w is again the weight, but now mu_k is the *coefficient of kinetic friction*.
Here's the rub: the coefficient of kinetic friction is always less than the coefficient of static friction. This is why, when you're trying to move a heavy object by shoving it, getting it moving is the hardest part (you have to fight the larger coefficient of static friction). Once it moves it's less work for you to keep it moving.
This explains why you want to pulse the break. If you're going very fast and your tires roll without slipping then your tire surface does not actually move in relation to the road surface. So if you apply the breaks then the tires will exert force on the road, which in turn exerts a force back and slows down the car, up to the maximum force possible by the coefficient of static friction.
However, if the breaking force exceeds that value then your wheels lock up and start to slip on the road. The coefficient of kinetic friction now dictates the maximum stopping force, which is smaller than before slipping and increases the time taken to come to a complete stop. So rather than breaking maximally hard, you should optimally break to the greatest extent that does not cause slippage. That's where 'pulsing the break' comes form. It avoids breaking so strongly that your tires loose grip on the road, therefore reducing the friction that stops your car. | [
"BULLET::::2. The ABS controller knows that such a rapid deceleration of the car is impossible (and in actuality the rapid deceleration means the wheel is about to slip), so it reduces the pressure to that brake until it sees an acceleration, then it increases the pressure until it sees the deceleration again. It c... |
Did Hispanics go to segregated schools in the southwest prior to brown v. Board? | Yes. But Brown v. Board of Education was not the ruling that ended the segregation. There are two types of segregation. One is "de jure" or by law segregation, meaning segregation based on laws on the books. The other is "customary" segregation, or segregation that was not based on laws but custom. California had de jure segregation, and was one of the earliest states to grapple with segregation, which makes sense since it had a large population of Hispanics. In Mendez v. Westminster, a 1945 case, the 9th Circuit Court of Appeals affirmed a decision that segregation of schools was unconstitutional. Brown v. Board of Education quoted Mendez and adopted much of its reasoning. In 1947, California's segregation of Hispanic schools ended. Following Mendez, a case in Texas, Delgado v. Bastrop Independent School District, led to a ruling that customary segregation was unconstitutional (Texas did not have de jure segregation). I am less familiar with the histories in the other states. I will note that the Treaty of Guadalupe required that Hispanics be classified as white in the Soutwest, which is why most segregation was customary, not de jure. | [
"Ten years after the US Supreme Court ruled in \"Brown II (1955)\" for school racial integration with \"all deliberate speed,\" many school districts in states with school segregation gave their students the right to choose between white and black schools, independently of their race. In practice, most schools rema... |
Does the earth rotating have any effect on us seeing the clouds move? | Directly? No. It's *not* like the clouds are holding still while the surface of the Earth rotates beneath them. The entire planet and the atmosphere rotate together, conserving angular momentum. However...
Indirectly? Yes. Unlike the surface, the atmosphere is free to move north and south. As the equator heats up from all the direct sunlight there, air moves towards the poles to redistribute that heat. Air that was once moving with same angular momentum as the surface at the equator has now shifted closer to the poles, and thus closer to the axis of rotation. In order to conserve angular momentum, then, it must start rotating faster, like an ice skater pulling in his arms. This helps create the prevailing westerlies, a.k.a. the jet streams, and explains why a lot of the weather at mid-latitudes (over most of the US and Europe) comes from the west and moves towards the east. | [
"According to Hendry, moving clouds may also sometimes confuse observers by creating induced motion. Hendry believes this occasionally makes observers also believe objects have suddenly disappeared or make a rapid departure.\n",
"However, because the planet is rotating underneath the atmosphere, and frictional fo... |
How were illegitimate children viewed in medieval China? | It depends on situation to situation. However, since your character is a female, she would be suffering a fair bit.
_________
It ancient China, bloodlines are very important, and it links directly to the status of a person (as well as the inheritance that may come with it).
A son born to the legal wife of a man would be considered the proper heir 嫡子, and would have first consideration in inheriting all estates and titles when the man passes away. This status would be irregardless if the age of any of the other sons the man may have with other women. As such, the proper heir would be pampered the most in the family, and given all the best benefits possible. Only when the proper heir has brothers by the same parents, would there be a question of inheritance.
A son born to a concubine of a man 庶子 would be considered part of the family, but would not stand to inherit anything. If his mother was especially pampered, he may be allowed certain privileges, but these would still be considerably less than that provided to the proper heir. However, if the man has no son with his legal wife, the concubine's son may be promoted to be the heir, often through having the legal wife adopt the son as her own.
A son who was illegitimate, however, would not be treated as part of the family at all. Although the term 庶子 was also used to describe such sons, if their mother was not married to their father, they would be regarded as outcasts, and most would not be even allowed to enter the family home. Even if the birth father did show some concern for the child by bringing him into the family, the boy would often be mistreated. As such, they would have no chance of inheriting anything from the family. The only exception would be if none of the man's wives or concubines have sons, in which case the illegitimate son would be adopted, but would have to cut off all ties to his birth mother.
The most famous examples would probably be the uncle-nephew pair Wei Qing 卫青 and Huo Qubing 霍去病. Wei Qing was the illegitimate child of Wei Ao 卫媪 and Zheng Ji 郑季. Wei Ao was married to another man, and life was difficult enough for the family's existing children (Wei Ao already had one son and three daughters with her husband), so she sent Wei Qing to live with his father instead. However, Wei Qing's father made the young boy shepherd sheep, and the legitimate children in the Zheng family bullied him, ordering him around like a slave. Thus he decided to go back to his mother's family, and was employed as a stable boy by his mother's mistress (princess Pingyang 平阳公主).
Huo Qubing was the son of Wei Qing's sister Wei Shao-er 卫少儿 and Huo Zhongru 霍仲孺. Huo Zhongru was fearful of acknowledging his son (most probably because Wei Shao-er was a serving lady to princess Pingyang, and he might be punished for being with her), and so Huo Qubing had to grow up being part of the servants in the princess' house. More fortunately for him, his auntie Wei Zifu 卫子夫 soon won the emperor's favour, and he was brought to court to be brought up and became a general at the age of 19.
_____________
These information would only apply to sons, because sons were the ones who stood to inherit family estates. Taking your backstory into consideration, a daughter born to an upper class family would be reasonably well brought up as a lady, and would be married off at a suitable age to be a bride to a (hopefully) rich or powerful family. However, an illegitimate daughter would not be accepted into the family at all, and would have to live off whatever her mother's family could provide for her.
If her mother's family had enough money, she may still have a relatively easy life, but would not be permitted much freedom as it would be considered a family shame to let her be seen on the streets. She would also be married off as soon as possible to cut off her ties to the family.
If her mother's family did not have money to provide for her, she would probably be sold off - if fortunate, to a family that has no children and are looking to adopt; if unfortunate, to the brothel so that her mother could gain some quick cash. The family would not want to keep her, since an additional person means an additional mouth to fill.
Hopefully, these information helps out. | [
"Many Han Chinese were enslaved in the process of the Mongol invasion of China proper. According to Japanese historian Sugiyama Masaaki (杉山正明) and Funada Yoshiyuki (舩田善之), there were also certain numbers of Mongolian slaves owned by Han Chinese during the Yuan dynasty. Moreover, there is no evidence that Han Chines... |
how do physicists shoot beams of small particles, like electrons, protons, and neutrons? | Electrons are easy; they're the social butterflies of the subatomic realm. They flit about very promiscuously. And because they have electric charge, they're easy to manipulate with electric fields.
The general process by which electron beams are created involves passing an electric current (which is a flow of electrons, essentially) through some kind of conductor that, when it gets hot, sprays electrons out. This phenomenon is called *thermionic emission,* and it generally means that the *thermal* energy of the electrons exceeds the *binding* energy of the electrons, so they escape from whatever material you're using.
Once the electrons get sprayed out of the hot cathode, their trajectories are "bent" by the presence of electric fields. The spray is therefore shaped into a collimated beam.
Proton beams are a bit more complicated, because protons don't come flying off of hot things the way electrons do. Generally the way proton beams are created is by taking hydrogen gas — which is just protons with electrons clinging to them — and stripping off the electrons with a strong electric field. Electrons are very light particles compared to protons, so it's possible to yank them away and send the protons shooting off in the opposite direction. From there, it's the same story: Shape the spray of protons with electric fields to create a beam.
Neutrons are even more complicated. They're electrically neutral, which means we can't touch them — literally. There's no way for you to accelerate a neutron. Instead, they have to be *made* by knocking hydrogen atoms together. Most hydrogen atoms contain just a single proton and a single electron, but some — called deuterium — have a neutron in there as well. If you smack two deuterium atoms together in the right way, they glomp together to make a helium atom, and eject the extra neutron. Do this in a very precise fashion, and you can create a beam of neutrons shooting out of a piece of metal. You can't control the beam the way you can with electrons or protons, because again, neutrons have no electric charge and can't be touched. But you get a beam nonetheless, which you can point at things to make a wide variety of interesting things happen. | [
"Particle-beam weapons can use charged or neutral particles, and can be either endoatmospheric or exoatmospheric. Particle beams as beam weapons are theoretically possible, but practical weapons have not been demonstrated yet. Certain types of particle beams have the advantage of being self-focusing in the atmosphe... |
Could a holographic monitor exist? Is it even possible? | I can't remember what the technology is or called, sorry. But I remember recently reading about a system using very very small mirrors on micro electromechanical systems (MEMS) to create a real "hologram" (of the kind formed by the interference of light)
Here we go: _URL_0_ | [
"A holographic screen is a two dimensional display technology that uses coated glass media for the projection surface of a video projector. \"Holographic\" refers not to a stereoscopic effect (for that, see Holographic display), but to the coating that bundles light using formed microlenses. The lens design and att... |
what is to be gained from this trip to pluto? | The objective is "Curiosity". If you're looking for a reason like Pluto is made up entirely of gold or vanilla ice cream, which is possible, than you're missing the point. The biggest point of all satellites is to sustain our appetite for curiosity. Humans are naturally curious, and exploring is in our genetic makeup as humans. Our pursuit of knowledge has begun since human has first existed and will continue until our last breath as a species. We are curious, what's out there in space, what do the other planets in our solar system look like, what are they made off, has there been any sign of other intelligent life form landing on the planet? The true objective is finding answers to questions we don't know, or don't understand...yet. | [
"BULLET::::- In \"World's Fair 1992\" by Robert Silverberg (1968), a U.S.-led expedition reaches Pluto in less than two weeks using a nuclear-powered spacecraft capable of continuous acceleration. The spacecraft, \"Pluto I,\" collects five crab-like indigenous Plutonians and returns them to Earth orbit for study.\n... |
Baghdad was one of the biggest centers of learning of its time. Because of items like the Baghdad Battery recently being found, how advanced was this city before the Mongols burned it to the ground? | I terms of macro technology, and the technology most people had access to Baghdad would have been about equal to most of the other cities around. Technology spreads quickly. It is likely that various things would have been more prevalent there because it was an extremely wealthy city as well as a trade and governmental center. But it is unlikely the city itself had many things that would not have been found elsewhere.
I am not an expert in the Baghdad battery and as I understand it, the recent political upheavals have taken a serious toll on the amount of archaeology happening in the region. | [
"The Abbasid Caliphate built the city of Baghdad in the 8th century as its capital, and the city became the leading metropolis of the Arab and Muslim world for five centuries. Baghdad was the largest multicultural city of the Middle Ages, peaking at a population of more than a million, and was the centre of learnin... |
What's the oldest prepared drink that could still be safely consumed? What's the oldest food? | The oldest food? 36,000 year old bison, if Dale Guthrie is to be believed (*Frozen Fauna of the Mammoth Steppe*, 1990). That is however an anomalous condition--fast-frozen in ice, and only a few morsels edible.
[edit: and no, we have no reputable accounts of people actually eating unfrozen mammoth in recorded history.] | [
"In 2018, the world's oldest brewery was found, with residue of 13,000-year-old beer, in a prehistoric cave near Haifa in Israel when researchers were looking for clues into what plant foods the Natufian people were eating. This is 8,000 years earlier then experts had previously thought beer was invented.\n",
"Ba... |
sound doesn't travel through space. it's a wavelength. light travels infinitely without degrading and it's a wavelength. what gives? | Sound is a vibration carried by a medium.
Light is carried by it's own particle, the photon. | [
"The mechanical vibrations that can be interpreted as sound can travel through all forms of matter: gases, liquids, solids, and plasmas. The matter that supports the sound is called the medium. Sound cannot travel through a vacuum.\n",
"Radio waves in a vacuum travel at the speed of light. When passing through a ... |
There's Planck Length, Planck Time, and Planck Temperature, each of which corresponds to a universal maximum of minimum(unless i am mistaken). Does this mean there can be such thing as a "Planck Number?" | The Planck length/time/temperature/mass etc. are not the largest/smallest quantity you can write down, nor are they necessarily the largest/smallest quantity of that type that you can write down. What they represent is the scale at which one must pay attention to both quantum mechanics and general relativity (the Compton wavelength and Sqhwarzschild radius of a Planck mass particle are equal to each other), and thus a scale beyond which one will need a theory that harmonizes quantum mechanics and general relativity (a quantum gravity theory).
Notice that these represent things with units, something about the scale of what is possible in the universe. Pure numbers are dimensionless, and so are a different kind of object to begin with. In addition, numbers are abstract quantities defined in the context of mathematics; the "Planck quantities" represent empirical features of the universe. We could, for example, imagine a universe in which the constants of nature had different values, thereby changing the Planck length; but changing those values won't change the number "5" to something else.
Here's another example: There is some element that has the largest possible atomic number; let's be generous and just say that that number is under 200. That just tells us about nuclei and atoms; it doesn't tell us that numbers above 200 aren't meaningful. | [
"In physics, the Planck length, denoted , is a unit of length, equal to . It is a base unit in the system of Planck units, developed by physicist Max Planck. The Planck length can be defined from three fundamental physical constants: the speed of light in a vacuum, the Planck constant, and the gravitational constan... |
What strategic threat did Nazi Germany actually pose to the United States before December 7, 1941? | Hitler's immediate aim was dominance of the continent; however, once this had been achieved, it us unlikely that Germany would have tolerated the United States as a rival for 'weltmacht', or world power. Between the u-boat menace, the German naval plan Z, and other potential threats (ie Amerika Bomber project, German nuclear programme), even if the United States did not face an immediate threat, it was a threat that would rear it's *very* ugly head in the future.
There were also distinct fears that the Germans would attempt to influence Latin America, such as Juan Peron's Novo Estado in Argentina. There were various American war plans for intervention, in Brazil as one example, to head off Nazi attempts to carve out a sphere of influence.
Hence the lend lease program. By strengthening Germany's enemies, the united States could prevent the need for intervention, unlike in WWI. This proved not to be the case however, and involvement in a second, more terrible world war would be required.
That answer your question? | [
"For several years after World War II, the United States developed and maintained a strategic force based on the Convair B-36 bomber that would be able to attack any potential enemy from bomber bases in the United States. It deployed atomic bombs around the world for potential use in conflicts. Over a period of a f... |
Why do babies frequently wake up in the middle of the night? | We all wake up during the night. That is normal during certain sleep stages. Unlike infants, we have learned to go back to sleep. These waking moments are usually short and we forget about them afterwards, or we actually be awake and go to the toilet, etc. The 'half-awake' state can cause sleepwalking. You'll be fully awake, but not fully conscious. The opposite happens as well: you're fully conscious, but your body is still asleep. That is when we experience sleep paralysis.
For infants this is new. Everything new can be scary, because they lack the experience to deal with it. I once had to calm a crying child who was thirsty, but actually half asleep. I had to keep him standing up to drink, then 'walk' him back to his bed to continue his sleep.
Small humans are weird. | [
"In terms of infant feeding, breastfeeding has been found to be associated with more waking at night than bottle-fed infants because of the infant’s ability to digest breast milk more quickly than formula. Thus, breast-fed infants have been observed to begin sleeping through the night at a later age than bottle-fed... |
How do we know about 1,700 planets? | Except in a [handful of cases](_URL_1_), we do not have direct images of those planets.
Rather, we detect the planets by their effects. Planets can be detected by slight changes in the wavelength of light of the host star; as the planet orbits the star, it pulls the star first one way and then the other, and due to the Doppler effect, this leads to a slight variation in the wavelengths of light we receive from the star. A second important method is the *transit method* (it is used by
the [Kepler mission](_URL_2_), for example). In this, scientists observe slight dips in the brightness of a star when a planet orbits in front of the star.
You can read about various other detection methods [here](_URL_0_). | [
"While astronomers had detected more than 180 extrasolar planets, XO-1b is only the tenth planet discovered using the transit method. It is only the second planet found using telephoto lenses. The first, TrES-1, in the constellation Lyra, was reported in 2004. The transit method allows astronomers to determine a pl... |
how do the denotations of words change so much over time? like gay meaning happy but now homosexual, or faggot meaning bundle of sticks to a derogatory term for homosexual. | [**Etymology of the word 'Gay'**](_URL_0_):
In the world's earliest meanings, going back to the 12th centry, it meant joyful, carefree, uninhibited, bright and showy, etc.
By the early 1800's, the word's implication of uninhibited pleasure had become euphemistically associated with immorality and lack of sexual inhibitions. Oxford dictionary at the time changed its definition of the word to include *"addicted to pleasures and dissipations. Often euphemistically: Of loose and immoral life”.*
The word became associated with illicit sex and prostitution. A promiscuous man might be euphemistically called a "gay lothario"; a prostitute might be called a "gay woman," a brothel called a "gay house."
By the 1920's the euphemistic use of the word had started to shift from implying sexual promiscuity in general, to specifically gay sex when the word was applied to men. The ongoing association with "bright and showy" clothing also became associated with frivolity and femininity in men.
But at the same time, the word also continued to be used casually to just mean carefree or joyous. To call a man "gay" to imply he was homosexual was a bit like saying he was "artistic" in the same manner, or to say a woman was "sporty" to imply she was lesbian. There was no non-degrading term for homosexual at the time.
In the mid-50's, gay people had started to organize and develop a sense of group identity. Within these groups, there was a desire for a new word to identify themselves with that was neither a slur ("sodomite" and etc), nor pathologizing ("homosexual" was a psychiatric diagnosis of mental illness). For decades the word "gay" had been used among homosexual men as a non-insulting euphemism, so in the mid-50's this word was adopted as a direct term of identity.
After Stonewall and the start of the modern gay rights movement in 1969, the use of the word "gay" to directly mean "homosexual man" (and later both men and women) became public knowledge. Which pretty much ended the casual use of the word to mean "carefree."
| [
"When used with a derisive attitude (e.g., \"that was so gay\"), the word \"gay\" is pejorative. While retaining its other meanings, its use among young people as a general term of disparagement is common. This pejorative usage has its origins in the late 1970s, with the word gaining a pejorative sense by associati... |
Why did European explorers translate the titles of the rulers of China and Japan as "emperor" but translate titles of the rulers of other East Asian countries as "King"? | hi! not discouraging other responses, but you might get something out of these earlier threads
* [Why the title of the Japanese monarch is translated as "Emperor", and the Thai monarch is called "King"?](_URL_2_)
* [What is the difference between a king and an emperor? Why were there empires in Rome, Japan, and China, but kingdoms in Africa and Europe?](_URL_0_)
* [Who were Emperors and who were Kings?](_URL_1_) | [
"The rulers of China and (once Westerners became aware of the role) Japan were always accepted in the West as emperors, and referred to as such. The claims of other East Asian monarchies to the title may have been accepted for diplomatic purposes, but it was not necessarily used in more general contexts.\n",
"Aft... |
how can something made of mostly empty space be “sharp”? | Imagine you took thousands of pingpong balls and superglued them together in to the shape of a knife blade, where the cutting edge has only one row of balls then gets progressively denser as it goes back.
Now imagine you took a bunch more balls and glued them together in to a big block but only using rubber cement which is not nearly as strong.
You would be able to take that big pingpong knife and basically push it through the block that you made. | [
"The most notable advantage of the scary sharp system is speed and cost. Anyone with access to sandpaper and a reasonably flat surface can sharpen any cutting tool, often with good results. Unlike traditional stones, no maintenance is required for the scary-sharp set-up, since the sharpening surface does not form a... |
Why can't we see in colour in a dark room? | Your retina has two types of cells: rods and cones. Cones see in colour, but their number is much smaller and they aren't very sensitive. Rods are much more numerous and sensitive, but they don't see colour.
Therefore, when you're in the dark you only see with your rods: you can make out shapes that your cones would never pick up, but you lose the capacity to distinguish colour.
On a side note, rods are also responsible for peripheral vision.
_URL_0_
_URL_2_
_URL_1_ | [
"This can be seen when the eyes are closed and looking at the back of the eyelids. In a bright room, a dark red can be seen, owing to a small amount of light penetrating the eyelids and taking on the color of the blood it has passed through. In a dark room, blackness can be seen or the object can be more colourful.... |
Who would like to discuss Foucault to me? | Interesting!
Foucault essentially suggests that we can use history and 'genealogy' to study certain institutions of contemporary/modern society and that this can give us a sense of their true purpose. One claim is that there is a distinction between truth and appearances, though this is as ancient as philosophy itself. Another claim is that 'ways of thinking' can imprison people through their very worlds of possibilities.
At the heart of his work is a claim that the ways in which people make sense of 'true' or 'false' or 'correct' or 'wrong' or 'logical or 'illogical' is formed through certain historical and philosophical processes that ultimately result from political considerations that are arbitrary but appear legitimate, natural, and rational. He is not saying that we don't have truth in our world (penicillin works!).
I think discourse theory is useful in understanding contemporary and modern societies. It is not the be all end all, but as with Descartes and Locke, Foucault provides tools which are uniquely suited for his society.
| [
"Foucault is a 1986 book on the work of Michel Foucault by Gilles Deleuze. Deleuze, like in his other works on major philosophers, thinks along with Foucault instead of trying to write a guide to his philosophy. The book focuses on the conceptual underpinnings of Foucault's extensive work by considering in depth tw... |
why don't our bodies have long term storage for air like we do with food? | Humans very rarely are in situations where they don't have easy access to air. Humans were until recently often in situations where they didn't have easy access to food. Hence we evolved to store fat, and not air. | [
"Good storage can extend the life of an item and is an important aspect of preventative conservation. Storage should be cool, dry, clean, and stable. Items should be kept away from radiators or vents, which can cause environmental fluctuations.\n",
"In addition to maintaining a shelf-life and reducing total mass,... |
what would happen if i play a negative mold of a record? | The needle would ride in a large flat groove between two peaks that would make the groove on a record.
If you could play it, it would play from the end to the beginning because the groove would go in the opposite direction.
Any sound you hear, besides the sound of the needle scratching on that flat space, would only be the left or the right because the needle can't touch both edges of a groove at the same time. It would also be backwards. | [
"Vinyl records are easily scratched and vinyl readily acquires a static charge, attracting dust that is difficult to remove completely. Dust and scratches cause audio clicks and pops and, in extreme cases, they can cause the needle (stylus) to skip over a series of grooves, or worse yet, cause the needle to skip ba... |
the difference between amortization and depreciation | If you're wondering which would be applied to something, depreciation is for things that physically wear out, like machinery, while amortization is for things that don't physically wear out, but eventually expire, like a patent. | [
"In tax law, amortization refers to the cost recovery system for intangible property. Although the theory behind cost recovery deductions of amortization is to deduct from basis in a systematic manner over an asset's estimated useful economic life so as to reflect its consumption, expiration, obsolescence or other ... |
Why didn't the indigenous Australian's have domesticated animals? Especially dogs? | They did. Not dogs because dogs aren't native to Australia but we used to have similar animals called dingos, which have been bred with dogs to the extent there are no pure breed dingos left, which were domesticated by the Aboriginals.
As for the other animals, the Aboriginals were a nomadic people and I imagine that carrying or waiting for a wombat or possum to follow you was not an appealing option when the place you're going to is going to have both that you can kill and eat without waiting around for them to follow you. | [
"European domestic dogs arrived in Australia in the 18th century, during the European colonization. Since then, some of those dogs dispersed into the wild (both deliberately and accidentally) and founded feral populations, especially in places where the dingo numbers had been severely reduced due to human intervent... |
why do some porn sites not need 18+ proof, but some do? | perhaps the one that needs no proof isn't operating in the US or a country that requires proof of age | [
"Pornography rated X18 is permitted by the law only if sold to persons over the age of 18 in registered stores. It is an offense to host a pornographic web site in South Africa because of the difficulty of age-verification and the requirement that pornography only be distributed from designated, licensed physical p... |
In the Game of Thrones TV series (and book) bastards from different regions all share a common surname to identify them, Snow or Flowers for example. Does this system have any evidence in history or was it invented by the author? | Responses covering more regions/cultures of Medieval Europe are welcome; meanwhile you may be interested in these
* [Bastard names](_URL_0_)
* [During the Middle Ages and the Renaissance, how was the surname of illegitimate children determined?](_URL_1_) | [
"The name at the head of this pedigree is that of another legendary Scandinavian, \"Geat\", apparently the eponymous ancestor of the Geats and perhaps once a god. This individual has also been taken as corresponding to Gapt, the head of the genealogy of the Goths as given by Jordanes.\n",
"There were two known br... |
When was music viewed as a popular way of protesting government actions? | One of the first instances I can think of is the [Carmina Burana](_URL_1_) - no, not Carl Orff's 1936 work, but rather the 11th and 12th century text that he drew his lyrics from. The Carmina Burana contains songs by the Goliards, a sect of the clergy who we see were very critical of the Catholic Church, particularly in their abuse of simony and penchant for greed.
A more mainstream example that comes to mind is probably the emergence of [opera buffa](_URL_0_) (comic opera) in the early 18th century. Because the intended audience of opera buffa was the middle classes (as opposed to opera seria, which was created largely for the aristocracy and royalty), librettists (story writers) often strongly satirized political conditions of the day. Since the scathing, lightly veiled commentary was couched in music, humor, and costumes, the underlying message was able to slip past typical censorship and into the mainstream. | [
"The tradition of protest songs in the United States is a long one that dates back to the 18th century and colonial period, the American Revolutionary War and its aftermath. In the 19th century topical subjects for protest in song included abolition, slavery, poverty, and the Civil War amongst other subjects. In th... |
how does a bread making machine work? | It automates the process of kneading (by mashing the ingredients with a rotating paddle, usually) then lets the dough sit (and beeps at you to remove the paddle so it doesn't get stuck), then bakes it. | [
"A bread making machine or bread maker is a home appliance for turning raw ingredients into baked bread. It consists of a bread pan (or \"tin\"), at the bottom of which are one or more built-in paddles, mounted in the center of a small special-purpose oven. This small oven is usually controlled by a simple built-in... |
The Roman Republic and Greek(Athenian) Democracy are traditionally dated to 509 BC and 508 BC respectively. Is this a coincidence or could they have possibly drawn inspiration from the same root cause? | It's not a coincidence at all, but not for the reason that you think. The traditional date if the expulsion of the Tarquins *must* be a later tradition attempting to imitate the Athenian one. That Rome had kings and that some of these kings were probably Etruscan is pretty certain, but the precise dating of the expulsion of the kings and the exact events as described by later sources like Dionysius of Halicarnassus and of course Livy are certainly an invention. The expulsion of the kings by two leaders, one of whom is incited by sexual assault (Collatinus for the Tarquins and Harmodius for the Pisistratids) against a female relative by a younger relative of the tyrant (Lucretia by Sextus Tarquin or Harmodius' sister by Hipparchus) is simply too obviously an imitation of the Athenian story to be accurate, and generally scholars dismiss the story as it is presented. I mean, for Christ's sake the Tarquins were expelled in exactly the same year as the Pisistratids, 510. This isn't the only time when we see obvious attempts to link the pre-Republican or earliest Republican traditions with Greek traditions of about the same period. Stories like Horatius Cocles and the sacrifice of the 300 Fabii are both quite obviously influenced by the defense of Thermopylae. These stories probably are based on something real (obviously the expulsion of the Tarquins is based on something that actually happened, as the kingship at Rome ended after all) or at least are based on older native traditions, but the Greek influence of obvious and very much there | [
"This is a list of the Greek democracies for which there is some evidence in the Archaic period, following Eric Robinson's book \"The First Democracies\" (Stuttgart, 1997). Most of them probably pre-date the establishment of democracy in Athens by Cleisthenes in 508-507 BC.\n",
"The period of Ancient Greece 4th c... |
Did the Mongols leave any long-term institutional or cultural legacy in the places they conquered? | one point of reference: in his book "Russia and the Golden Horde", Halperin concludes that while the Mongols had a traumatic effect on the Russians, they left surprisingly few traces of their culture or language, considering that they were the overlords of Russia for centuries. the Russians had to pay their taxes and toe certain lines, but their main interaction with the Mongols was paying taxes or tributes or being raided as punishment for disobedience. at least that's how Halperin tells it. he did note details on legacies when they came up, maybe aspects of court etiquette, but i can't remember.. i'll look it up if no one else knows.
and I don't have a particular source on it, but I've read many times the claim that the Mongols had similarly little effect on China - their interaction with the populace was focused on extraction and security, aspects in which they were completely replaced when they were driven out of the country. | [
"When the Mongols conquered most of Asia and Russia in the 13th century and constructed the Mongol Empire, they lived as minorities in many of the regions they had subdued, such as Iran and China. As a result, the Mongols in these regions quickly adopted the local culture. For example, in the Persian Ilkhanate the ... |
in mmos, what stops a game from having large scale battles? | For starters everyone's pc would have to be capable of rendering that many characters in one spot, as well as register all the actions made by those characters. But I would imagine there would be a lot of stress on the servers having everyone in spot. | [
"The battles are fought in a tactical role-playing game fashion. However, unlike other games in this genre, the battles tend to last less than a minute, with the exception of boss battles, and require little tactics. This makes the game stand out in its genre and may have also led to its limited mainstream success ... |
What percentage of the human genome defines our body and what percentage defines our brain? | that is not how it works. many of the areas of the genome which code for "body" also code for brain structure. | [
"Studies on human brain size, largely based on participants of European ancestry, tend to find an average adult brain volume of 1260 cubic centimeters (cm) for men and 1130 cm for women. There is, however, substantial variation between individuals; one study of 46 adults, aged 22–49 years and of mainly European des... |
How are space probes like Cassini protected from colliding with asteroids and space scrap? | There really isn't much in space, it's not like the movies. For example when we say "asteroid field", we mean that there is a 1km or larger asteroid every 2million miles or so, which is further than the distance from the earth to the moon. [Source is stackexchange](_URL_0_) but it's simple math.
The odds of a satellite hitting anything in space is so astronomically low that it's not worth doing anything about it. You really need to try if you want to hit anything. | [
"Double Asteroid Redirection Test (DART) is a planned space probe that will demonstrate the kinetic effects of crashing an impactor spacecraft into an asteroid moon for planetary defense purposes. The mission is intended to test whether a spacecraft impact could successfully deflect an asteroid on a collision cours... |
How does the body maintain itself without correct nutrients? (example inside) | She doesn't, and that causes all kinds of problems. Quoting the article you linked
"Readman could not be reached for comment but according to her doctors, she is malnourished and has the health of an 80 year old.
"That sounds like an accurate assessment," says Lisa Kaufman, a pediatrician at Village Pediatrics who has not treated Readman. "A diet of instant noodles has likely wreaked incredible amounts of havoc on her organs. The body—especially one that's still developing—needs protein, minerals, and nutrients to grow; that's just basic common sense. Without it, this girl has probably suffered stunted growth and IQ, osteoporosis, heart and kidney damage, and high blood pressure. Her lifespan has likely been shortened as well."
| [
"Normally, individuals obtain the necessary nutrients their bodies require through normal daily diets that process the foods accordingly within the body. Nevertheless, there are circumstances such as disease, distress, stress, and so on that may prevent the body from obtaining sufficient nutrients through diets alo... |
What's the best source to obtain scientific papers regarding a particular subject? | In physics, math and astronomy, the [arXiv](_URL_0_) is a free pre-print server you can use. When scientists in these fields write papers that become accepted for publication, they often post their papers on this archive. All papers are free access, so you don't need to worry about being trapped behind a paywall. | [
"The international book inventories and historical collections of the library are one of a kind and made available to researchers in a scientific reading room for studies. A scholarship program for foreign scientists, financed by the Foreign Office, pursues the goal of supporting the research in the area of the int... |
what is nat and what does it do / what is static nat? | You have a single Internet connection, and you only get a single address from your Internet Service Provider, but you have multiple devices that you want to connect to the Internet- your laptop, your phone, your game console, and so on.
One way to connect multiple devices through a single connection is Network Address Translation, or NAT. You have a single device (your router) connected to the public Internet, and the rest of the devices are connected to a private network. When each of your devices wants to communicate across the Internet, they send messages to your router and your router relays the information to the destination, making all the traffic look like it comes from that one public facing Internet connection. Your router keeps track of which device was communicating with which server so when the responses come back, it knows which device to send it to.
This works fine for sending traffic, but with only one IP address connected to your router, none of your devices other than that router are publicly accessible from the outside Internet. So if you want to run a server (whether it's a website or a game server) on one of your devices, there's no direct way for people outside your network to send requests to your computer. Static NAT is a way of setting up your network so that your router forwards the requests it receives to a specific computer within your network. That way, your computer inside the private network can receive requests from the greater Internet. | [
"NATS is an open-source messaging system (sometimes called message-oriented middleware). The NATS server is written in the Go programming language. Client libraries to interface with the server are available for dozens of major programming languages. The core design principles of NATS are performance, scalability, ... |
why are distance runners so skinny? | The more you weigh, the more work you have to do to move yourself over a long distance. Sprinters need to be muscular since short distance events are more about accelerating to your top speed quickly and maintaining that speed for a few seconds while distance events are about maintaining a moderate (but still very fast) pace for anywhere from 14-15 minutes for a 5k to just over 2 hours for a marathon. | [
"Various studies have shown marathon runners to be more economical than middle distance runners and sprinters at speeds of 6–12 miles per hour (10-19 kilometers per hour). At those speeds, film analysis has shown that sprinters and middle distance have more vertical motion than marathoners.\n",
"Biomechanical fac... |
why did canada get rid of the penny? | Canada got rid of the penny because the penny costs more to make than it's worth.
A good video: [Canada gets rid of the penny](_URL_0_)
Edit: put in the right link | [
"The Government of the Dominion was able to fix the problem caused by the importation and commerce created by American coinage imported into Canada. they printed additional $.25 notes with no plate number. This ended the importation and Canadians used Canadian notes to fuel their economy.\n",
"The 1850s in Canada... |
i hope everyone here knows about the simple english wikipedia (url in text) | This is amazing! My brother will love this! | [
"The Simple English Wikipedia is an English-language edition of the online encyclopedia, Wikipedia, primarily written in basic English and special English. It was launched in 2001. It is one of five Wikipedias written in an Anglic language, the others being the English Wikipedia, the Pitkern-Norfuk Wikipedia, the S... |
Isn't it an evolutionary advantage for a living disease not to be fatal to us? | Not necessarily, though logically you would think so since it makes all kinds of sense. While some viruses or other diseases do evolve toward lower lethality, it appears to be more of a special occurrence, rather than the rule. Take the [rabies virus](_URL_3_), for instance. It causes a disease which is almost invariably fatal. Until the [Milwaukee protocol](_URL_5_) was introduced in 2004, no one had been recorded to survive rabies exposure without receiving the vaccine in time, however attempts to replicate the Milwaukee protocol have since failed, but extended the patients' lifetimes by around 30 days as /u/AGreatWind mentioned below. In essence, it was about 100% fatal in humans (not in all animals, however), and yet [is believed to have been around for about 1500 years](_URL_6_), giving it plenty of time to develop reduced virulence if it was going to.
In the 1950s, a poxvirus known as [myxoma virus](_URL_1_), normally spread by mosquitoes or fleas, was released as a biological control measure against an exploding European rabbit (*Oryctolagus cuniculus*) population, which had been introduced in Australia in the 1800s. Myxoma virus's native host is the South American rabbit *Sylvilagus brasiliensis*, in which it causes only mild virulence. In European rabbits however, it causes a disease known as [myxomatosis](_URL_2_), and is highly lethal. The original strain released into the European rabbit population in Australia was known as Standard Laboratory Strain, or SLS (super original, I know), and was phenomenally lethal - approximately 99.8% of rabbits infected with it died, usually within 14 days. A population of over 600 million rabbits was reduced by 85% to around 100 million, before the rabbit population began to rebound.
[Here is an excellent discussion piece on the evolution of viral virulence](_URL_0_). To summarize however, the rabbits experienced a strong selective pressure for alleles conferring protection to the disease, as the mortality of immunologically naive European rabbits in Australia exposed to SLS decreased from > 90% to < 50% in only a few generations, and eventually dropped even lower. At the same time however, the virus itself diverged into a number of different circulating strains (all of which have been shown to have diverged from SLS) with reduced mortality. Eventually though, below a certain limit (approximately 50% mortality), the virus was no longer able to spread efficiently, presumably because the viral titer in the skin (where mosquitoes or fleas would bite) was not high enough to survive the transfer to the next host. As such, the virus evolved toward *moderate* lethality, rather than a state of *a*virulence.
So while it would seem to make sense that a disease would want to develop some sort of non-fatal infection, it is usually not the case. Instead, viruses tend evolve toward enhanced *transmission*, which can come about through decreased or even increased mortality. [I highly recommend reading the aforementioned link](_URL_0_) for a more thorough explanation on disease evolution, as this applies to more than just viruses. Additionally, the same blog has [another excellent post on how the rabbits themselves evolved toward enhanced resistance to myxoma virus](_URL_4_), if you are interested in learning more about it. | [
"Many human diseases are capable of evolution. Viruses, bacteria, fungi and cancers evolve to be resistant to host immune defences, as well as pharmaceutical drugs. These same problems occur in agriculture with pesticide and herbicide resistance. It is possible that we are facing the end of the effective life of mo... |
why does it feel good to talk badly about someone who’s wronged us? | When we talk badly about someone who’s wronged us, we are contrasting their behavior to ours; making us feel entirely separated from ‘wrong’ behavior. When we can view ourselves (and help others to view us) as separate from wrong behavior, we feel better. This is similar to watching TV shows such as ‘Hoarders’ and ‘My 600 lb Life’ in my opinion. Often, the viewers that derive pleasure from these shows are those that feel good about being able to say that at least their house is not “that bad” or at least they aren’t “that large”. | [
"that no one is perfect but most people are good; that people can't be judged by their worst or weakest moments; that harsh judgments can make hypocrites of us all; that a lot of life is just showing up and hanging on; that laughter is often the best, and sometimes the only, response to pain.\n",
"I could reply: ... |
can churches in the united states of america offer sanctuary? | No, churches in the US do not have the legal authority to prevent the police from entering to make an arrest. | [
"At its peak, Sanctuary involved over 500 in the United States which, by declaring themselves official \"sanctuaries,\" committed to providing shelter, protection, material goods and often legal advice to Central American refugees. Various denominations were involved, including the Lutherans, United Church of Chris... |
How does the evidence support the fact that photons are particles? | No, because the ionization happens depending the frequency, not the total energy of incident radiation (intensity, proportional to amplitude^2 × frequency). If the thing was purely wave-like, any wavelength of light should be able to ionize the atom, given an amplitude high enough. This does not happen, experimentally. | [
"One can say that the photon is not a particle but as a mere quantum of energy that is usually exchanged in integer multiples of ħω, but not always, as it is the case in the above experiment. From this point of view, photons are quasiparticles, akin to phonons and plasmons, in a sense less \"real\" than electrons a... |
assuming weight loss is purely about "calories in vs. calories out," how is it possible for the body to go into "starvation mode" and temporarily prevent weight loss from occurring | Short answer... It doesn't.
Long answer, it stores a bunch of water.
So, your body has fat cells. Those cells store fat. When they're full of fat, that's it. They're 100% full fat cells. However, as you start losing weight and using those fat stores, those cells start getting smaller. So at say 50% full of fat, it's like a half deflated balloon. So as you lose weight you get hundreds of millions of half deflated fat cells.
Because our body is super efficient, it doesn't want to get rid of the cells yet because "we might need them again". But also half full cells are a waste as well. So the body starts replacing the Fat with water. Once the fat cells are completely full of water for a while, the body, being as efficient as it is, decides that maintaining these cells isn't worth the effort, we were holding on just in case, but it seems we're just wasting energy to do that. That's when your body starts getting rid of the water and the cells themselves.
Edit: TL:DR - Body replaces the fat in fat cells with water for a while before getting rid of the fat cells. (This is part of the reason it's important to drink a lot of water when attempting to lose weight) | [
"As the calories required for energy homeostasis decreases as the organisms's mass decreases, if a moderate deficit is maintained eventually a new (lower) weight will be reached and maintained, and the organism will no longer be at caloric deficit. A permanent severe deficit, on the other hand, which contains too f... |
When/How did the idea of citizenship first develop in (I believe, correct me if I'm wrong) Athens? | Unfortunately, Athenian/Attic identity develops during a period of time when our sources are scant. However, most scholarship today tend to emphasize the role of the Peisistratids of forging the disparate regions of Attica into a single entity. Archaeological evidence shows that period as one of religious consolidation, as large pan-Attic monuments appear on the Acropolis, and the Panathenaic games forged a common identity. | [
"The history of foreign migration to Athens dates back to the archaic period. Solon was said to have offered Athenian citizenship to foreigners who would relocate to his city to practice a craft. However, metic status did not exist during the time of Solon.\n",
"Several thinkers suggest that ancient Sparta, not A... |
When did doctors and psychologists begin to see sex as part of a healthy lifestyle and even necessary? Was there open debate about it? | The one time there's a question I can tanswer, and I do not have my sources on hand, curses. With that said, there are actually a few names like Kinsey, Masters & Johnson, and a few others that come up, with Kinsey and Johnsons making the claim the claim that sex was not just for procreation. Kinsey, if I'm not mistaken, was the first to suggest treatment for transgendered individuals. Unfortunately, I do not have my text with me, but if you like I can elaborate more, later tonight?
[this wiki article provides some basic info] (_URL_0_) but the text I am using for my course on human sexuality has way more information, and it's truely fascinating how sexuality is treated and how we see a change in attitude through the late 19th and 20th centuries.But again, the wiki, of course, does not have all the information
edit: If promises of explanations are not acceptable, I apologize and will just elaborate later tonight | [
"All seven volumes of \"Studies in the Psychology of Sex\" were widely accepted in the scientific community, even with the progressive perspectives in which it portrayed human sexuality and perversions. Despite this, the book was not published in England until the middle of the 20th century, as it was strongly beli... |
how does the atm count and verify cash inserted in envelopes? | > How do machines count cash in envelopes?
They don't. They record the transaction and when the drop box is transferred to a bank later on the bank employees manually count and verify the amount of money was correct. | [
"The operation is rudimentary: the cashier swipes a customer's ATM card on the terminal and keys in payment amount. The cardholder then selects his bank account and keys in the ATM Personal identification number (PIN). If the requested amount is successfully debited from the customer's account, receipts will be pri... |
How devastating would a kinetic weapon (projectile dropped from orbit) actually be? | By increasing distance from earth and mass, you could scale them up to the size of the impact that created the moon. The question is why you would do that. Much easier to pack explosives into a vehicle that doesn't have to travel that far. | [
"Kinetic weapons have always been widespread in conventional warfare—bullets, arrows, swords, clubs, etc.—but the energy a projectile would gain while falling from orbit would make such a weapon rival all but the most powerful explosives. A direct hit would presumably destroy all but the most hardened targets witho... |
META: Can we talk about the clear increase in "throughout history" or trivia-seeking questions? | nsdwight has the gist of it. As the sub grows, we attract a larger audience, an audience that, unfortunately, contains more people who don't know the rules and don't bother to read them. We do our best to filter vague and low-effort questions, but can't catch all of them. If you see them, report them! Everyone can contribute.
Unless you're talking about submissions that are not being removed- if that's the case, care to provide examples? | [
"For the first time in the festival Stozhary history the philosophic round-table discussions took place. Headed by Nazip Hamitov (Ph. D., professor, author and radio programme host, writer, script writer and psychoanalyst) the discussions analysed wide spectrum of issues involving: \"Eros and Thanatos in cinema\", ... |
What is the minimum amount of gravity of a planet needed to sustain a breathing atmosphere? | Don’t know the math for this, but Saturn’s moon, Titan has a very thick atmosphere but only has about 2% the mass of Earth. Other factors play into a planet having an atmosphere, though. A good magnetic field prevents solar wind and deadly cosmic rays from stripping one away. | [
"The atmospheric pressure on Mars is about 150 times less than that of Earth. In such a thin atmosphere, a balloon with a volume of 5,000 to 10,000 cubic meters (178,500 to 357,000 cubic feet) could carry a payload of 20 kilograms (44 pounds), while a balloon with a volume of 100,000 cubic meters (3,600,000 cubic f... |
Can you feed a bird so that it gets too fat to fly? Or would it die from health complications before it ever reached that point? | I remember hearing at a lecture about birds given by a guy who runs a conservation that some types of vultures will eat until they can't fly because they don't find meals that often, and will just walk on the ground until a predator appears, in which case they will vomit in its face to distract/blind it, thus lowering their weight and letting them fly again. | [
"More radical approaches have been studied. A duck or goose with a ventromedian hypothalamic (VMH) lesion will tend not to feel satiated after eating, and will therefore eat more than a non-lesioned animal. By producing such lesions surgically, it is possible to increase the bird's food consumption when permitted t... |
Can an ant find its way home? | Depends... the Argentine ants have a mega-colony in CA that stretches over 560miles.
The long and short of it is that ants are blind without chemical scent trails. So unless his home colony has ants that have made it a mile away into your yard, the ant will not find its way back.
It would in all likelihood get attacked by your yards colony. There are rare exceptions of colonies that take "prisoners", but probably not in your yard. | [
"In the natural world, ants of some species (initially) wander randomly, and upon finding food return to their colony while laying down pheromone trails. If other ants find such a path, they are likely not to keep travelling at random, but instead to follow the trail, returning and reinforcing it if they eventually... |
Istanbul to Ankara: What factors were involved in the switch? | In addition Istanbul (or Konstantiniyye) had for long been the symbol of the multi-cultural ottoman empire (and ofc. the greek, byzantine empire), containing significant amounts of non-turkish elements (specifically Greek) which Atatürk despised.
When Atatürk wanted to create his new turkish national state Istanbul simply had too much history behind itself to be used as the symbol of a revolutionary nationalistic and modern moment. Ankara were thus preferred.
In addition the aforementioned "occupation" of Istanbul by the allied powers greatly influenced the decision as you cant really lead the struggle against the greeks from occupied territory.
| [
"BULLET::::- The Ankara Agreement was signed in the capital of Turkey, between representatives of the European Economic Community (EEC) and Turkey, and provided for gradual entrance of Turkey into the European Community.\n",
"The city held the strategic position between the Black Sea and the Mediterranean. It was... |
Questions regarding nicknames | The Viet Cong were referred to using the military phonetic alphabet (V-C = Victor Charlie) shortened to Charlie. | [
"Nicknames can be a descriptor of a personality characteristic or the opposite of a personality characteristic. These types of nicknames were often used in fairy tales such as \"Snow White\". Sometimes such nicknames may be indicative of a physical disorder.\n",
"Nicknames are usually awarded to a person and they... |
how is it legal to have tinted license plate covers? | The ones I've seen leave the license plates readable, the idea is if a speed trap camera takes a picture it'll make the plate unreadable in the photo. Fortunately they don't actually work, so no one really cares.
If your plate is obscured to the point where you can't read it with the naked eye, it is extremely illegal. | [
"Until 2014, the license plate showing white text on black background, with aluminum plate Scripture by removing the black coating production reasons silver precipitates. Decorative fonts are officially not allowed, but are tolerated in private vehicles; License plates do not exist.\n",
"Depending on the type of ... |
vampires might not be real, but how exactly does the internal anatomy work of creatures that live strictly off of blood? | Their anatomy isn't that different from other similar animals. They drink blood which goes into their stomach and is digested to get nutrition. There is a lot of energy to be gained from eating blood just like eating other parts of an animal. | [
"Vampires in the Buffyverse live on a diet of blood, preferring fresh human blood; they can distinguish the blood of different animals by flavor, and those who do not drink human blood enjoy that of otters. They require no other food or drink, and although they can ingest it they generally find it bland. Prolonged ... |
why are tv cooking shows allowed to kill live animals but other tv/movies can't harm animals? | Nothing under US law prohibits the airing of content that shows violence against or the killing of live animals.
Content providers largely self impose not airing animal abuse as it would upset program advertisers by associating them with less than reputable content, audiences have a cultural predisposition to be against unnecessarily harming animals, and building an image of someone who provides that kind of content reflects poorly on a businesses brand. | [
"Pets are not allowed at the event. This is due to concerns for the safety of both the animals (loud noises and an inhospitable environment), and the participants. In addition, fireworks, flares and fire lanterns are not permitted. \n",
"The local residents and festival organizers claim that the dogs are killed h... |
What was the mindset for veterans who lived through both WW1 and WW2 | What was the "mindset" for them? And are you looking for generalities, because there were a LOT of veterans with a lot of different thoughts about a lot of different things. What does your question actually mean? I don't think you can possibly get a substantive answer to this question, as vaguely worded as it is.
This subreddit needs an FAQ on how to write a question about history that can actually be answered in the way the subreddit itself demands answers. | [
"The Canadian writer Farley Mowat says that many returned veterans after World War II sought a meaningful life far from the ignobility of modern warfare, regarding his own experience as typical of the pattern. In Canada, those who sought a life completely outside of the cities, suburbs, and towns frequently moved i... |
what is the theoretical limit to wireless communication transmission speed? what is the limiting factor? | There's two factors:
There's the speed of light, which limits the *latency* — the delay between sending and receiving.
The second is *bandwidth*, which is how much data can be sent in a certain amount of time with a certain amount of power.
The Pluto probe currently has a bandwidth of about *1 kilobyte per second*. This upper limit exists because the *modulation* of the signal — shifting it up and down in frequency — has to be slower, the pulses have to be longer, to prevent them from being drowned out by background noise.
If the probe could transmit with more energy, the pulses could be more easily distinguished from background noise, and so could be shorter, and the bandwidth increased.
There's nothing that can be done about the *latency*. That's a hard limit on the physics of the universe.
If there were amplifiers / repeaters every so often along a path between the probe and Earth, the *bandwidth* **could** be increased, because the power of the transmission would be stronger, the closer it physically is to the receiver.
There are, of course, significant logistics challenges behind deploying, powering, and managing those hypothetical amplifiers and repeaters. | [
"According to the Acceptable use policy of most providers where this limitation is in place, the speed is comparable to that of an old dial-up connection. However, there were numerous complaints by customers that the actual speed was lower. In response to these complaints, Telenet (cable internet provider) in Octob... |
is there any solid reason why we view/record videos and pictures in a rectangular way. and why not just a square? | This has been asked in various ways before though I'm pressed to think up good search terms.
A simple answer is that our field of vision of wider than tall so it makes sense for video to be the same. | [
"When a surface is at a high angle relative to the camera, the fill area for a texture will not be approximately square. Consider the common case of a floor in a game: the fill area is far wider than it is tall. In this case, none of the square maps are a good fit. The result is blurriness and/or shimmering, depend... |
Are all the particles in the universe quantum entangled or does that only happen under specific conditions? | I would argue yes as entanglement as well as superposition are intrinsic aspects of a quantum world, but saying that 'everything is entangled' is not a particularly useful or helpful notion. The reason for this is that entanglement happens too much and too easily killing all the delicate quantum effects we so carefully try to cultivate in the laboratory. This process is called decoherence and is a major reason why the weird quantum world generates "classical" physics as we move to larger systems. Here's an excellent enthusiast level look at it:
* Zurek. Decoherence and the transition from quantum to classical -- REVISITED. PHYSICS TODAY, 44:36-44 (1991/2003) _URL_0_
What people call EPR entanglement is more correctly described as isolated entanglement. Systems which are allowed to coalesce with each other, but not with the outside world. This only happens under specific conditions. | [
"Quantum mechanics proposes that pairs of virtual particles are being created from quantum fluctuations in this \"empty\" space all the time. If these pairs do not mutually annihilate right away, they could be detected as real particles, for example if one falls into a black hole and its opposite is emitted as Hawk... |
how does the weather change so drastically for just a few days and then go back? | If you have ever listened to the weather man you've probably heard the term "Cold front" or "Warm front" as they tell you the weather. These fronts are masses of air with various attributes, they could be cold & moist, warm & dry, warm & moist, etc. The leading edges of these fronts are pretty strong and they can push away or go under the current mass of air in an area, when this happens the weather changes.
Sometimes these changes are just drops or increases in temperature, sometimes these changes result in lots of steady rain, and sometimes they result in violent thunderstorms. **But the ELI5 is that there are masses of air types floating around and they push and interact with each other and help create our weather.**
So right now a cold front has entered your area and probably has gone under the warm air you've been having and once that cold air has left your warm air will will return (although it really never left, in some cases it was just above the cold front!) | [
"Typically, if there is little wind shear, the storm will rapidly enter the dissipating stage and 'rain itself out', but, if there is sufficient change in wind speed or direction, the downdraft will be separated from the updraft, and the storm may become a supercell, where the mature stage can sustain itself for se... |
why is being transgender not considered sexist? | It isn't about the things you like to do, it's about who you feel you are. These things are quite different. Like you said, if a boy wants to play with barbies or a girl wants a toy gun, whatever! It doesn't have anything to do with being transgender. I think the confusion for you might be coming from the fact that if children exhibit these traits and then grow up to be transgender it's not because those things are inherently "girl things" or "boy things" but because culture often dictates that they are. So if a little boy feels like a girl (but doesn't know how to express it) he will do things that in his mind feel right, and those things will often be things that his culture has deemed "girl things". | [
"Many transgender people see gender identity as an innate part of a person. Some feminists also criticize this belief, arguing instead that gender roles are societal constructs, and are not related to any natural factor. Sex-positive feminists support the right of all individuals to determine their own gender and p... |
If forced to spin, whether for a game or as a contest, what is the most effective way to avoid sever dizziness? | Do what ballerinas do. Keep your head in one position and turn it fast and stop, fast and stop, fast and stop. This is precisely why they do this - to not get dizzy. | [
"In some trick games--typically ones in which players are not penalized for winning tricks, and there is no requirement for trumping or following suit when possible--players may \"slough\", or play a card face down. A card so played is incapable of winning the trick; but sloughing has the advantage that the other p... |
Wondering about the origins of current Japanese cultural norms | Japanese people show emotion... they're just more subdued about it, and you need to look for non-verbal clues a bit more than you're probably used to.
It was considered a loss of face to show strong emotions in public, if you're asking about the origin of this. | [
"Japanese culture has evolved greatly from its origins. Contemporary culture combines influences from Asia, Europe and North America. Traditional Japanese arts include crafts such as ceramics, textiles, lacquerware, swords and dolls; performances of bunraku, kabuki, noh, dance, and rakugo; and other practices, the ... |
Looking to learn more about Canadian History | From my perspective — and it's biased toward the Yukon/Alaska — I'd recommend working your way through Pierre Berton's bibliography. While he wrote some duds here and there, most of his 50 titles are pretty good.
I'd recommend *The Klondike Fever*, *The Promised Land: Settling the West* and *Marching As To War* as three to get you started. Those three condense a lot of his bibliography. Once you've gotten through those, grab his two volumes on the War of 1812 (one covers 1812-1813, the other 1814-1815) his two volumes on the Canadian Pacific Railway, *The Arctic Grail*, *Vimy*, *Niagra* and *The Great Depression.* | [
"BULLET::::- Schultz, John. ed. \"Writing About Canada: A Handbook for Modern Canadian History\" (1990), chapters by experts on politics, economics, ideas, regions, agriculture, business, labor, women, ethnicity and war.\n",
"The historiography of Canada deals with the manner in which historians have depicted, an... |
why as seen on tv products are sold in "3 payments of $19.95" or something like that. | Primarily for two reasons:
1) Splitting up the cost of a product over multiple payments gives the potential buyer the impression that the product is actually cheaper than it is. Ex. One payment of $60 vs three payments of $19.99. The fact that the sellers do not round up is also by intention. Even though we see $19.99 or $19.95 we don't equate that with $20, our immediate association puts it with $19 which seems cheaper to us.
2) There is some flexibility with these payments as by being able to pay in installments reduces a small portion of the financial burden on the buyer - making him/her more likely to buy it. It's like saying "Well, okay, I can pay $19 bucks this month and get the product, and worry about the two other payments later!" Out of sight - out of mind. Hope this helps! | [
"The product is sold direct to consumers in these countries using an instalment-based payment model. This ensures that the product is affordable to people who would be unable to afford a large lump sum payment.\n",
"BULLET::::- Product A currently sells for $10. The seller decides to increase the price to $15, bu... |
Were wolves domesticated only once, with all dogs descended from that single progenitor population, or did the process of domesticating wolves occur independently in different societies? | While we have a fair bit of overlap, given that this predates written history, you may want to consider X-posting this to /r/AskAnthropology as well as this falls within their purview. And for that matter, I would note that /r/AskScience would also be an appropriate venue given the biological science aspects of the question. | [
"An examination of the genetic evidence by Carles Vila and others confirms that the progenitor of the domestic dog is the wolf (\"Canis lupus\"). The suggested date of their domestication is about 100,000 BC. While accepting the wolf as the ancestor, paleontologists and archaeologists believe domestication came muc... |
Are fields real or just a mathematical tool? | The strongest statement physics can ever make is "this model makes accurate predictions." It cannot tell you whether the model is what's "really" going on or not, because there is no other way to test the model.
Whether something is "real" or not is a matter of philosophy. You could argue that any model which makes perfect physical predictions is reality because all correct descriptions of reality are equivalent, sort of like they're just different languages expressing the same concept. I dunno, it certainly isn't science at that point. | [
"When mathematicians employ the field axioms, the intentions are even more abstract. The propositions of field theory do not concern any one particular application; the mathematician now works in complete abstraction. There are many examples of fields; field theory gives correct knowledge about them all.\n",
"The... |
why is it more common for employers to provide health insurance plans as opposed to individuals getting their own insurance? why doesn't this group approach differ from other types of insurance, like home, life and auto, where customers often get insurance directly with an insurance company? | This is an accidental remnant of wage controls during the world war. Certain industries could only offer so much salary, ao they started offering healthcare as an artificial raise. Then that became expected. Then it started to become law. Businesses could negotiate good rates, and paying 5k for someone's healthcare saved you the taxes that having to pay that in salary would cost. Eventually you were told that the goal of adulthood was to find a job that offered a good salary and healthcare.
It really isnt a system anyone would set up intentionally, but it accidently started and has slowly become too "normal" for most people to consider changing it. | [
"In the article \"Why Tie Health Insurance to a Job?\", Emanuel said that employer based health insurance should be replaced by state or regional insurance exchanges that pool individuals and small groups to pay the same lower prices charged to larger employers. Emanuel said that this would allow portable health in... |
How do fields form, especially those right next to densely wooded areas? | Can you give an example of this?
| [
"Seemingly treeless fields may contain seeds and living tree stumps and roots which have the ability to sprout new stems and regenerate trees. Even this 'bare' millet field in West Africa contains hundreds of living stumps per hectare which are buried beneath the surface like an underground forest.\n",
"In agricu... |
why does it sound odd shortening "you are" to "you're" in the sentence "i'm ready when you are"? | Because in this form the word *you* is emphasized, spoken more loudly. So also emphasizing the *are* leaves the listener wondering: *are* what? | [
"The infinitives of 'I am' are ' 'to be', ' 'to have been', and ' (often shortened to ') 'to be going to be'. Other irregular present infinitives are ' (sometimes in Plautus and Lucretius ') 'to be able', and '/' 'to eat'. \n",
"Now is often used at the end of sentences or phrases as a semantically empty word, co... |
Do arteries unclog eventually? Or is plaque build up permanent? | HDL participates in a process called [reverse cholesterol transport](_URL_0_) that can remove ~~plaque~~ cholesterol from peripheral tissue. As qxrt points out, this might not remove the plaque itself. | [
"The progressive accumulation of plaque within the artery wall over decades is the setup for vulnerable plaque which, in turn, leads to heart attack and stenosis (narrowing) of the artery (known as coronary artery lesions). IVUS is of use to determine both plaque volume within the wall of the artery and/or the degr... |
Can anyone please explain the difference between LUMENS and candela per square meter (CD/sqm) (In human language) as a measure of light brightness? | A lumen gives the *total* amount of human-visible light given out. How bright the light actually is will depend on how wide the beam is. A very wide beam with a lot of lumens is as bright as a very narrow beam with a few lumens.
A candela is maybe a more useful unit here. A candela tells you how intense the human-visible light is in every direction. It's independent of the size of the beam - it's basically the brightness "per beam size", if that makes sense. A 1 candela beam with a very small beam width looks just as bright as a 1 candela beam with a very large beam width. The both illuminate with the same brightness, it's just that one covers a bigger area than the other. So it's maybe a better unit for a headlight. Though it might not matter if all lights have similar beam-widths.
However, "candelas per square metre" is a bit odd. As a unit, it makes sense, and it's something that we use in astronomy. It means something like "the brightness in a specific direction per square metre of source". That is, it's useless unless you actually know the size of the light source. I don't think that's the intent - it's probably mislabelled, and it really means just candelas.
Given that, it's quite likely that they're using the units incorrectly. So I wouldn't completely trust when they say "lumens" that they don't actually mean "lumens". Which isn't super helpful, I know. | [
"The lumen is defined as amount of light given into one steradian by a point source of one candela strength; while the candela, a base SI unit, is defined as the luminous intensity of a source of monochromatic radiation, of frequency 540 terahertz, and a radiant intensity of 1/683 watts per steradian. (540 THz corr... |
What were the predominant armor types worn in ancient southwest Asia? | The most common armour was scale body armour with a helmet of approximately conical or hemispherical shape. Surviving scales are commonly bronze, but bronze has an advantage in survival over rawhide and iron, which were also used. Descriptions of metal armour often describe it "gold" or "silver", which might refer to bronze and iron, respectively. Scale body armour could be either short, to the waist or hips, or long, covering to about knee level. Most armours appear to have been sleeveless or with short sleeves.
Next most common would be lamellar, either short or long, and sleeveless or short-sleeved, like scale armours. Again, surviving lamellae are often bronze, but rawhide and iron were used too.
Mail probably appears in the region in late antiquity, and was in use by the early 3rd century AD. The first major users of mail in the area appear to be the Sassanids.
There are some armours with long sleeves for the arms, notably cataphract armours. Scale sleeves were used, and art suggest lamellar sleeves. Sassanid armoured cavalry would typically have long mail sleeves. Horse armour was also in use. I don't recall seeing mail horse armour, but both scale and lamellar horse armour were used.
There was some use of plate armour, from the mid/late first millenium BC. Body armour included round plates used to protect the torso, and more complete plate cuirasses, but these seem to be much less common than scale/lamellar/mail which appear much more often in art. Plate greaves were used; this was quite likely Greek/Hellenistic influence.
H. Russell Robinson, "Oriental Armour" covers antiquity in the first chapter. | [
"Protective clothing and armour have been used by armies from earliest recorded history; the King James Version of the Bible [Jeremiah 46:4] translates the Hebrew סריון \"ÇiRYON\" or שריון \"SiRYoN\" \"coat of mail\" as \"brigandine\". Medieval brigandines were essentially a refinement of the earlier coat of plates... |
why does raw seafood smell so much stronger than other animal proteins? | Chemicals in fish digestive systems that break down food (ie: other fish) turn on the fish's own body when it dies, speeding up decomposition. This is why you're supposed to gut a fish asap.
The chemicals that cause the odor itself come from the decomposition and are called amines.
_URL_0_ | [
"Seafood, however, would logically have a more distinctive flavor. (The extent of its divergence is not consistent; tuna was said to taste enough like chicken that a prominent tuna canner named its product Chicken of the Sea.) Also, although mammals are tetrapods, very few mammals taste like chicken, which implies ... |
How did knights poop? | I'd like to make it clear before I post that I'm not an academic historian, however I've done a fair bit of reading on medieval arms and armour as I'm a practitioner of HEMA and re-enactment - I've also worn, sparred and occasionally even pooped in various types and combinations of chain and plate.
Based on research by [Jones](_URL_3_) (2011), the term 'knight' has been used to describe a large and very diverse range of people. Medieval writers even referred to Julius Caesar and Alexander the Great as knights. I'm going to assume for the purposes of this answer that you're referring to knights in the sense of the martial elite of the middle ages/medieval period. The types of armour worn by knights between the 11th and 16th century varied quite dramatically - technological developments meant that armour changed significantly and quickly in that period. The precise types of armour that were commonly worn until the mid 14th century are hard to ascertain as pictorial sources are very open to interpretation - hardened leather and metal are difficult to differentiate from illustrations and this is compounded by the fact that fabric surcoats were commonly worn over armour, meaning that the armour underneath was seldom shown. Archaeological evidence also suggests that many knights used armour that was out of date - knights and men-at-arms, especially those who weren't very wealthy, commonly wore armour that was around 50-60 years old.
Evidence on metallurgy technology suggests that metal plate armour wasn't in common use until the late 14th century. The chain/ringmail, padded clothing and leather armour preceding that wouldn't have been hard to remove if you needed to urinate/defecate. Operating under the assumption that when you refer to knights being 'suited up' you mean suits of plate armour worn by European knights and men-at-arms I'll focus on that. By 1400 or so metal plate armour began to be worn in the form of breastplates and faulds (articulated plate skirts) covering the torso, rebraces, vambraces and pauldrons covering the arms & shoulders, sabatons, greaves, cuisses and poleyns protected the legs and feet - all of these would have been attached to padded clothing worn underneath. The groin was still protected by a mail skirt - meaning that it could be easily lifted and padded undergarments pulled down in order to defecate.
Plate armour of the type you're most likely thinking of was developed in the 15th century, when it diversified into Gothic and Milanese styles. Gothic armour emphasised mobility and flexibility with a more articulated design and used a mail skirt or underpants (braies) to cover the groin. Gothic gauntlets typically featured individually articulated plates for each section of the finger, meaning that the wearer would still have sufficient dexterity to lift up a skirt and/or pull down the padded cloth or chain underwear covering the arse. Milanese plate was typically heavier and less articulated, but still had a short, articulated skirt at the back meaning that the undergarment could be pulled down. Milanese 'mitten' gauntlets didn't have individually articulated fingers but wearers still retained dexterity as the finger and thumb plates were attached by a single leather strap just below the knuckle with a leather glove underneath (see [here](_URL_1_) for an example).
In the 16th century 'Maximillian' plate was developed - it was lighter, more highly articulated and sometimes [gorgeously decorated](_URL_5_). Gauntlets remained largely the same and plate skirts and codpieces became more common (chain was still used at the rear in some cases), although the arse was still accessible due to plated skirts being either flared or shortened at the back, meaning dropping trou and pinching one out could still be done relatively easily. By the mid/late 17th century plate armour was mostly obsolete due to firearms becoming more and more common.
The reasoning behind the derrière being so accessible in plate armour designs wasn't just to make taking a dump easier - in order for your legs to have proper freedom of movement you can't just strap a plate to it. Similarly, if you want to ride a horse (as was common for knights) then having metal plates between you and the saddle makes riding much more difficult and incredible uncumfortable. It would also make sitting down a rather problematic experience. Sources are Jones (as linked above), [Lawrence](_URL_4_), and [Clayton et al.](_URL_0_). If you're interested in medieval knights and their arms & armour then Jones is definitely worth a read. [This Channel 4 Documentary](_URL_6_) is also very informative and is really enjoyable; I highly recommend checking it out.
When you're in a stressful situation (such as being in or gearing up for battle) then the body's adrenal response as a 'fight or flight' mechanism [stimulates your colon and rectum to contract](_URL_2_), meaning you're unlikely to need to drop a deuce when you don't have the time to pull up your skirt and drop trou. Accidents probably happened if the individual was experiencing 'digestive discomfort', but that's purely conjecture.
That's the limit of my experience and reading on the issue, I hope it helps!
| [
"Typical tournament armor for jousting would be padded with cloth to avoid damage from an opponent's lance, and prevent to metal of the pauldron from scraping against the breastplate. This protective cloth pad would extend about half an inch from the rolled edge of the armor, and it was secured in place with rivets... |
When we mix two colors, do we create a new pigment, or are the colors still separate, just impossible to distinguish? | Tiny spots of yellow and green. Paint mixtures aren't chemical reactions, there is no bonding. I mean, I can't speak to all paints, but oil, watercolour, and acrylic at least are all distinct pigments suspended in various solutions. | [
"In this traditional scheme, a complementary color pair contains one primary color (yellow, blue or red) and a secondary color (green, purple or orange). The complement of any primary color can be made by combining the two other primary colors. For example, to achieve the complement of yellow (a primary color) one ... |
Would you feel yourself spinning in absolutely empty space? If not, how is this possible? | Since spinning is a constant acceleration (constant change in velocity vector) the fluids in your ears should be displaced, and thus you should still be able to feel that you are spinning and get nauseous. If the spin is slow enough, I'd imagine that with zero reference points and a nearly non-existant fluid displacement, you wouldn't know you are spinning. | [
"The most common general symptom of having the spins is described by its name: the feeling that one has the uncontrollable sense of spinning, although one is not in motion, which is one of the main reasons an intoxicated person may vomit. The person has this feeling due to impairments in vision and equilibrioceptio... |
How long does light last for? | > What is light,
Light is what you perceive when a photon of light hits a photo-receptor protein in one of the cells in your eye. The protein gets energy from the light that prompts a conformaitonal change (it wiggles), and this wiggle causes a change in the rate-of-fire of the neurons in your eye. This signals ("tells") the brain that you have seen light.
Light is made of little tiny particles called photons. All photons travel at the "speed of light", c, around 300,000,000 m/s. They travel at the speed of light from every frame of reference. So if you are moving towards the light, you still measure it moving at c. If you are moving away from the light, it is still moving at c, from your perspective.
There are an infinite number of different photons that can be created, because each photon has a specific "energy". There are high-energy photons and low-energy photons, and everything in between. High-energy photons are dangerous, and can cause cancer (gamma rays, X rays). Low energy photons are pretty much harmless (radio waves, visible light).
All the different energies of light lie on a "spectrum". Humans can only detect a narrow range of light energies, from red to purple. Red photons have less energy, green have an in-between amount, and purple has the most. Above purple is ultraviolet (higher energy). Below red is infrared (low energy).
{Humans glow. We emit photons. But these photons are low-energy infrared photons, which humans can't detect. So we can't see ourselves glow. But snakes can detect infrared photons. So snakes can see us glow!}
> what is dark?
Dark is a human/animal perception. It occurs when no light hits the sensory apparatus (the eye).
> Does it degrade in any way
Yes and no. When it is travelling through empty space, light does not have an expiration date. We can look in the sky and see photons from 1 billion years ago. It is only when light hits and interacts with an object that it changes. Light can be absorbed and converted to heat. Or converted to energy (as in solar cells or plants doing photosynthesis). | [
"Multiples of the light-second can be defined, although apart from the light-year, they are more used in popular science publications than in research works. For example, a light-minute is 60 light-seconds, and the average distance between Earth and the Sun is 8.317 light-minutes.\n",
"Lighting begins at the Inte... |
Is it possible to have multiple earth like planets in a planetary system? | It really depends on the planets. Venus and Mars are both within the "Goldilocks zone" for Sol. Depending on who's math they are right on the edge though. Venus ended up with a runaway greenhouse effect and now has an acid atmosphere, Mars lost its magnetic field and was stripped of its atmosphere. At one point, both of those planets were quite similar to earth so it can be done.
The safe zone isn't a single orbit, it is a rather wide area so you could easily sneak a couple planetary orbits in there. There are billions of stars out there, anything that can exist almost certainly does exist, we just haven't found it yet. | [
"Planets that orbit just one star in a binary pair are said to have \"S-type\" orbits, whereas those that orbit around both stars have \"P-type\" or \"circumbinary\" orbits. It is estimated that 50–60% of binary stars are capable of supporting habitable terrestrial planets within stable orbital ranges.\n",
"Star ... |
how come seedless cherries aren’t a thing like seedless grapes and oranges? | The "seed" in a cherry is called a pit, and if I'm not mistaken, it's where the juicy part of the cherry came from. Similar to dates and plums. In contrast, the seeds of grapes and oranges are intended to produce more grapevines/orange trees | [
"The fruit is a deep burgundy colour, with a sour flavour and is popular in jams. It is cultivated in small plantations. Due to infertile seeds it can only be propagated from cuttings or division. Hence all cultivated material is derived from clones of wild plants. Plants take at least six years to produce fruit. S... |
The maya treated the lower classes extremely poorly for over 2000 years, why was there no successful rebellion? | Can you elaborate? In what way do you think the Maya lower class was mistreated (and consistently for so long at that)? Is there some particular piece of evidence that led you to that conclusion? | [
"By the 9th and 10th centuries, this resulted in collapse of the system of rulership based around the divine power of the ruling lord. In the northern Yucatán, individual rule was replaced by a ruling council formed from elite lineages. In the southern Yucatán and central Petén, kingdoms generally declined; in west... |
Is temperature vary based on the point of reference? | Good question, and yes. We understand the asymptotic Hawking temperature, it becomes a constant for sufficiently distant observers at rest. In simplified units it takes on the form,
T = k/2pi
k = surface gravity at event horizon
Let's look at Schwarzschild coordinates,
ds^2 = -(1-R/r)(cdt)^2 + (dr)^2/(1-R/r) + angle terms
R = Schwarzschild radius
This corresponds to a frame which "hovers" above the black hole at a fixed radius, as you can see the temperature is modified by the curvature,
T = a/2pi = (k/2pi)/√(1-R/r)
* Unruh. ["Notes on black hole evaporation"](_URL_1_) Phys.Rev. D14 (1976)
Here we see, the hovering temperature relies on the inverse of the square root of the curvature. There are two important features:
1. As you recede to flat space r-- > big, you recover the famous Hawking temperature.
2. As you approach the Event Horizon of the black hole, the temperature blows up to infinity. We can attribute this to the acceleration an observer must maintain to not fall into the black hole.
What about free falling into the black hole? Like if I decided to jump in? Unfortunately, I could not find an exact mathematical treatment--except to say that there is an exact solution for 6-dimensional spacetime.
* Brynjolfsson, Thorlacius. "Taking the Temperature of a Black Hole" JHEP 2008. _URL_3_
* Kim, Choi, Park. "Local free-fall Temperature of GMGHS Black Holes" Phys. Rev. D 89. 2013. _URL_2_
* _URL_0_
All these suggest that the free falling observer will see a finite radiation bath (which isn't precisely thermal) on the order of the Hawking temperature even as they cross the horizon--so they won't burn up! | [
"It makes good sense, for example, to say of the extensive variable , or of the extensive variable , that it has a density per unit volume, or a quantity per unit mass of the system, but it makes no sense to speak of density of temperature per unit volume or quantity of temperature per unit mass of the system. On t... |
Why can't we run 64 bit applications in a 32 bit operating system, even if the CPU supports 64 bit? | A 32 bit operating system running on an x64 processor causes the processor to run in a 32-bit mode. For example, it uses 32-bit addressing in its virtual memory system.
See for example: _URL_0_ | [
"The 64-bit version runs on CPUs compatible with x86 8th generation (known as x86-64, or x64) or newer, and can run 32-bit and 64-bit programs. 32-bit programs and operating system are restricted to supporting only of memory while 64-bit systems can theoretically support of memory. 64-bit operating systems require ... |
Why do rivers meander? | I'm not an expert but...
Water takes the path of least resistance. So if the ground is lower in one spot vs another, that is the direction the river will take. Or if the ground is softer or more prone to erosion, that will help to guide the path of the river.
Once the river is bent, the erosion will be strongest on the outside of the curve, which will cause the curves to become more and more pronounced over time. | [
"Meanders are sinuous bends in rivers or other channels, which form as a fluid, most often water, flows around bends. As soon as the path is slightly curved, the size and curvature of each loop increases as helical flow drags material like sand and gravel across the river to the inside of the bend. The outside of t... |
why is a vehicle released in (for example) 2018 called a 2019? | There isn’t really a singular reason rather a few different things that led to it.
Ford started releasing the next year’s model in the fall for those in agriculture. That was when they had the most money so they released the model at a time that people could buy next year’s model instead of buying the almost year old current year model.
Other companies followed suit and started releasing in the fall, after WWII they settled on Oct 1 for an industry standard.
Jumping to the 60s this also coincided with the rising television industry’s start of the fall season which always sees a spike in viewership which meant more people seeing ads | [
"On 5 November 2013, Toyota USA announced the 2014 model year Trail Teams edition would be called the \"Ultimate Edition\" and that the 2014 model year would be the last for the FJ Cruiser in that market. It continued to be made for sale in other markets such as Australia until its export to that market was discont... |
who controls the internet? | Short answer is "no" on both accounts.
Longer answer is that yes, there is monitoring on many levels of the internet that is maintained by agencies and law enforcement as well as by NGOs and lobby organizations.
A government agency is unlikely to care that you're torrenting, but will care if you're making terrorist plots. Law enforcement will likely not care about your torrents either, but will care if you run a pedophile ring, and NGOs such as the MPAA will very much care about your torrenting, but they ahve very limited access to the internet.
The US government does not control the internet. It isn't unlikely that they exert greater control than they let on through surveillance , as indicated by the last few years' leaks, and them asking corporations to install backdoors in software.
The US did not create the internet either, really. They _did_ create ARPAnet, which is a predecessor and have had a great hand in shaping and developing the internet, or at least universities have, but the greater question is "what is the internet", which makes things more complicated.
The internet is many things. The internet is infrastructure - It is radio towers to distribute wifi and cables to run ethernet through, some of them transcontinental and transoceanic.
The internet is hardware - It is routers and switches and modems and servers
The internet is also software, with applications, sites, server software, DNS, storage, databases.
Many of these layers and segments are distributed, and none of them are government controlled - Most are controlled by working groups and organizations that work with maintaining and developing standards, and more hands-on with private companies who manufacture and support the hardware and software which runs these things.
To reconnect to your first question: Yes, there is monitoring by agencies and law enforcement to hinder illegal activities such as trade with drugs, weapons and people, wire fraud, financing or plotting terrorism etc, but it's not one single entity that monitors the entire internet for it, rather government agencies and law enforcement that all work according to the laws and interests of teir nation (or the EU, or NATO, or whatever), with collaboration where possible and necessary.
This also involves a lot of real-world work as well, monitoring people, suspects, their activities, working to establish links between online personae and real-world people etc. | [
"Internet service providers in many countries are legally required (e.g., via Communications Assistance for Law Enforcement Act (CALEA) in the U.S.) to allow law enforcement agencies to monitor some or all of the information transmitted by the ISP, or even store the browsing history of users to allow government acc... |
What elements/compounds give Jupiter its colors? | **The short answer**: Hydrocarbon hazes, Rayleigh scattering, and some unknown compound.
**The long answer**: For the primary whites and browns that cover most of the planet, you need to realize that almost everything you see when you look at Jupiter is ammonia clouds, which on their own are bright white. Some latitudes are regions of upwelling (zones), and have high ammonia cloud-tops, while other latitudes are regions of downwelling (belts), and have low ammonia cloud-tops. In between these high and low heights sits a thick brown hydrocarbon haze, very chemically similar to smog. The cloud-tops in the zones are sticking up above most of the haze and thus appear fairly white. The cloud-tops in the belts, though, lie below the haze layer, and thus appear colored brown by the overlying haze.
For the occasional bluish regions seen just to the north and south of the equator, these are some of the rare cloud clearings that occur in very strong downwelling regions. We're actually peering through the ammonia top cloud layer, and perhaps even down through the ammonium hydrosulfide middle cloud layer and the bottom water cloud layer. So, in those regions we're looking at just clear air, which has the exact same color as it does one Earth, blue. This is entirely due to Rayleigh scattering, the same reason that Earth's sky is blue.
Then there's the reds, notably in Jupiter's Great Red Spot, although also occasionally seen in another big vortex here and there. As of right now, we don't actually know what makes the Great Red Spot red - this is generally known as the Jovian chromophore problem. Since this color is only seen in very large vortices, it's believed to be caused by some mixture of compounds already present on the planet getting pushed very high in the atmosphere by these vortices. In three dimensions, the Great Red Spot is essentially shaped like a wedding cake, so the cloud-tops at the center of the spot are at very high altitudes where there's a lot more ultraviolet light. You can end up producing all kinds of odd substances through UV photochemistry of trace substances in the atmosphere, and the working hypothesis at this point is that it's some kind of imine. | [
"Spectroscopically, the Jupiter trojans mostly are D-type asteroids, which predominate in the outer regions of the asteroid belt. A small number are classified as P or C-type asteroids. Their spectra are red (meaning that they reflect more light at longer wavelengths) or neutral and featureless. No firm evidence of... |
how did spacex develop rocket technology so quickly? | It's not like they're starting with the same technology as nasa when it was founded. | [
"While SpaceX spent its own money to develop its first launch vehicle, the Falcon 1, the development of the Falcon 9 was accelerated by the purchase of several demonstration flights by NASA. This started with seed money from the Commercial Orbital Transportation Services (COTS) program in 2006. SpaceX was selected ... |
Why were the Turkish states able to assimilate Anatolia so quickly? Why didn't Persia or the Balkans assimilate? | I'll start off my answer by pointing out that significant parts of Iran and Afghanistan were in fact Turkified; Azerbaijan, parts of Fars, northeastern Iran, and northern and central Afghanistan. The main reason this happened, I would argue, is that the climate and habitat of these regions were (similarly to Anatolia) suitable to Turkish nomads. [I'm not too knowledgeable on Ottoman rule in the Balkans, so I'll leave that to someone else.[Though I would hazard a guess that Ottoman government was considerably more sedentary than their earlier Turkic colleagues and so were less concerned with the settlement of migrating Turkic tribes.]]
The reason for this suitability lies in the mix of mountainous and flat terrain. The Turkic nomads who invaded Iran from Central Asia, and eventually moved further into Anatolia, practiced vertical transhumance. This involved the seasonal migration of the nomads' animal herds: down into the valleys/plains during the winter, and up into the lower reaches of the mountains during summer.
The reason for the noticeably smaller degree of Turkification in Iran and Afghanistan compared to Anatolia is due to the presence in Iran/Afghanistan of competing groups. Kurds, Lurs, Pashtuns and many other Iranian groups already engaged in forms of nomadic pastoralism and so would have provided competition for space with the incoming Turks.
Anatolia on the other hand, was populated mostly by urbanised, sedentary Greeks, Armenians, and Syriacs. There likely were some native nomadic groups, but certainly not to the same degree as Iran and Afghanistan. Consequently, the migrating Turks faced relatively little competition during their settlement of Anatolia.
There were obviously other factors involved, such as the power vacuum in Anatolia after the Battle of Manzikert as the regional nobility fled to Constantinople to take part in the Byzantine intrigues (pun definitely intended) to select a new emperor, or in the remarkable ability of these Turkic tribes to assimilate Islamic and Christian ideas into their pre-existing pagan-influenced governing ideology. However, to reiterate it is the suitability of the terrain that I find to be the most important factor in the Turkification of these regions. | [
"In the resulting chaos, the Turks easily overran much of the Byzantine empire and, despite Byzantine reconquests and occasional western incursions in the form of crusading armies, a series of Turkish states were established in Anatolia. These Turkic tribes came around the south end of the Caspian Sea for the most ... |
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