question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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If I whip my head around to get my hair out of my face, am I causing my brain to hit my skull? Is this as bad as I imagine? | Someone asked pretty much this same question [yesterday](_URL_0_), and myself and others gave a complete answer. | [
"Only a few studies have been conducted on this condition. A theory behind the condition is that nerves innervating scalp hair follicles send pain messages back to the brain when the follicle no longer has a hair in it, in a similar way to phantom limb pain. Another theory is that people who have this condition (so... |
why are the president and vp always from the same party or "the twelve amendment" | Back in the day, the candidate with the most votes was the President, and the candidate with the second most votes was the VP. Since they were of differing political parties, I'm sure you can see how they wouldn't always see eye-to-eye, so the Constitution was amended after a couple of election cycles.
The 12 Amendment sets the precedent that the Candidate selects a running mate who becomes the VP upon winning the election. | [
"The Twelfth Amendment explicitly states the also apply to being Vice President. It is unclear whether a two-term president could later serve as Vice President. Some argue that the Twenty-second Amendment (which bars the President from serving more than two terms) and Twelfth Amendment both bar any two-term preside... |
if the max amount of money an individual or corporation can donate to a politician is $2700, how can the koch brothers and other millionares donate millions of dollars to the candidate of their choosing? wasn't the $2700 rule put in place specifically so that politicians couldn't be bought? | Yes. They don't donate directly to the campaign in those amounts, though: they donate to the parties and to political action committees (so-called "Super PACs" in particular), which have higher limits or no such limit. | [
"BULLET::::- Per year, an individual may not contribute more than $50 to any single small donor committee, more than $500 to any other single political committee, more than $2,000 in aggregate to a political party, or more than $2,500 in aggregate contributions.\n",
"As of February 2014, it had over 100 Democrati... |
why am i not ticklish? | Upvoted, I'm not either and my GF calls me a robot, I'm curious as well. | [
"Charles Darwin theorized on the link between tickling and social relations, arguing that tickling provokes laughter through the anticipation of pleasure. If a stranger tickles a child without any preliminaries, catching the child by surprise, the likely result will be not laughter but withdrawal and displeasure. D... |
can someone speak to the amount of human ancestor fossils we have? | _URL_1_
_URL_0_
Ignore the successful black guy.
Anyway, there are lots of ancient hominid fossils, you can read about them [here](_URL_2_)
You can tell how long something has been sitting in the ground by comparing how radioactive it is to how radioactive things that haven't been buried are. The oldest fossil on that list was dated by using Beryllium isotope dating. | [
"In 1994, near the Awash River in Ethiopia, Tim D. White found the then-oldest known human ancestor: 4.4 million-year-old \"Ar. ramidus\". A fossilized almost complete skeleton of a female hominin which he named \"Ardi\", it took nearly 15 years to safely excavate, preserve, and describe the specimen and to prepare... |
wrinkle resistant/non-iron clothing | It depends on the material. Natural fibers like cotton and linen wrinkle easily, though wool does not. Basically, cotton fibers (for example) have little elasticity - check a shirt or jeans, if you can find some with 100% cotton and see how well they stretch compared to other fabrics. They do have a little, but not much. Cotton more than linen, for example. That is why they don't bounce back as easily to their original shape - winkle free.
Most microfibers (like polyester) are the opposite - like sports clothing. It doesn't wrinkle, and has a "memory" of it's original shape; as it's really stretchy, it can bounce back to the memory position of the fibers - unwrinkled.
That's why it seems "modern" - we haven't been able to produce microfibers for all that long.
Edit: Not all cloths are made that way because natural fibers have other benefits (e.g lack of smell development for cotton, lightness of the fabric for hot climates for linen) and many people feel more comfortable with them than with synthetic fibers. | [
"Wrinkle-resistant fabrics are textiles that have been treated to resist external stress and hold their shape. Clothing made from this fabric does not need to be ironed and may be sold as non-iron clothing. While fabric cleaning and maintenance may be simplified, some wearers experience decreased comfort.\n",
"Wr... |
Is a vacuum cleaner's "sucking power" limited to the atmospheric pressure around it? | You are correct that the pressure differential is limited by the atmospheric pressure, but what you aren’t considering is the volume of air moved. A vacuum of higher power will be able to move more air than a lower powered unit. Air flow is as important as pressure differential and you need both to effectively move material | [
"A central vacuum typically produces greater suction than common portable vacuum cleaners because a larger fan and more powerful motor can be used when they are not required to be portable. A cyclonic separation system, if used, does not lose suction as the collection container fills up, until the container is near... |
How clean were clean houses 100 years ago? | Hobbyist literary historian here. I would say "no." When you read books from that era, you'll occasionally hear mention of such outlandish products as "soap," "bleach," "lye," and "ammonia," all of which have long been used to bring about household cleanliness. Vinegar is as also as old as dirt (not quite, but it has been around for thousands of years) and is a handy cleanser still used today by the environmentally conscious. Someone else would have to verify it's historical use though.
All that aside, for the simple removal of dirt when sterilization is not an issue, you may be surprised to learn that a rag wet with water will do wanders. | [
"Clean House is a home makeover and interior design television show, originally broadcast from 2003 until 2011 which aired 10 seasons of programs on the Style Network. Originally hosted by Niecy Nash and later by Tempestt Bledsoe, the show brings a four-person cleanup-and-renovation crew to the homes of families to... |
Can medical science manufacture medical antibodies? | They definitely use antibody injections to treat certain diseases, however I don't think that its feasible to use them for an acute infection. The power of the adaptive immune response is not just in the ability to make antibodies, but to make ever increasingly effective antibodies and then to "remember" how to make those antibodies should a similar infection occur later on. If you simply inject antibodies that can neutralize or opsonize (coat a pathogen, facilitating phagocytosis), you haven't actually taught the immune system anything.
The idea behind vaccination is you give your immune system a taste of the antigen without actually causing a full blown form of the disease it would normally cause. The immune system then develops highly specific antibodies for the antigen and retains the ability to make those antibodies quickly in the future through memory cells. If you encounter that antigen a second time, the immune response will be able to wipe out the infection before you even experience symptoms. | [
"Synthetic antibodies have shown their utility in a number of applications. Their use within the field of research lies predominantly in the life sciences as reagents for protein capture and as protein inhibitors. Within diagnostics they have been utilised in applications ranging from infection and cancer screening... |
why does the us military have troops out in other countries, when there is not a specific war being fought? | Numbers are from [this article](_URL_0_):
Generally speaking, the US deploys its forces for non-violent reasons for exactly the reason you would expect: to protect its own interests. Anyone looking for a deeper meaning (either nobility, or conspiracy) is mostly trying to find something that isn't there. I'll break down the top regions/nations:
1. Europe: During the Cold War, NATO feared a land invasion from the East Bloc/Warsaw Pact. Because the Red Army *dramatically* (by an order of magnitude) exceeded NATO's continental armies in size, the limiting factor in winning a war in Europe would be the rate at which American forces could deploy.
The Soviets built a large two-pronged naval force designed to block resupply of Europe by America (first, the massive Soviet submarine fleet; and second, Soviet long-range bombers designed to fly from northern Russia to the Atlantic and fire cruise missiles at allied shipping). The response to this was to preposition a large contingent of US troops in Europe, so that even if the Soviets were able to close the Atlantic they would have to face a large American force on the continent.
Europeans liked it because it strengthened their own defense against Soviet agression and "committed" the Americans to a war if the Soviets invaded. Americans liked it because it strengthened their own diplomatic hand against the Soviets (they weren't isolated to the Western hemisphere).
2. Southeast Asia: Immediately following WWII, most of South Asia was a wreck. Imperial Japan had thoroughly destroyed existing political structures in Korea, China and a host of other countries. The only existing Democracy at the time (Australia) didn't have the means or the men (numbers) to enforce regional stability for US trade. In addition, there was the need to enforce the peace treaty signed with Japan. Despite all that, the US's main focus unfortunately was Europe and so within a decade of WWII two of the largest countries in Asia (Korea and China) had collapses politically and were rapidly subsumed into dictatorships.
The US became involved in the conflict with Korea after seeing how the situation in China played out, mainly motivated by once again Euro-centric anti-communist thinking. Ultimately, it was only by the skin of their teeth that the Americans were able to fend off Chinese forces in the Korean War. Follwing that, the need for a persistent manned presence to stabilize US trade interests in Asia was apparent. It's also worth noting that the US is -by far- more highly reqarded in Korea (where the troop density is probably the highest in the world) than anywhere else. This suggests that this deployment is pretty well-liked in country.
The US has a large presence in Germany mostly for historical reasons (initially, there was a lot of anti-German sentiment left over from the two world wars, then it was because West Germany was the front line of the Cold War). Other nations have large US contingents for several reasons (convenience, to facilitate the NATO unified command structure and cross training, as a diplomatic tool (not to threaten, but as a "look, we spend money in your country" thing), etc).
South Korea has 30,000 troops because there is no Korean Armistice, and North Korea has a tendency to fire heavy metal objects at South Korea without first notifying the proper authorities.
Japan has 50,000 troops mostly because of its strategic position as the "gateway to Asia" (from the Pacific) - Hawaii is basically the midpoint between the US and Japan, and so the next closest friendly nation that is central to the region is Japan. Historical reasons play a big factor here as well, but with an ascendant and at least non-allied China inertia is not the biggest factor like it is with Germany.
| [
"Although the United States did join the war, due to Great Britain's control over the Atlantic Ocean, the only fighting for the U.S. Army was in Europe on the Western Front. The American army was transported by ship across the ocean so it could fight the Germans in France.\n",
"BULLET::::- The United States Army ... |
; why does saliva give grip? | If we went down to a micro-scale, we would see that the vast majority of surfaces we consider to be "smooth" (like paper) are not smooth at all, but rather have many bumps and ridges (it would be like looking at a gravel driveway). Due to this, our hands, which have ridges as well (especially finger prints), fail at creating a strong "bond" with these smooth materials because we are rubbing ridges against ridges, meeting very little resistance, and failing to fill in all of the valleys in-between these tiny peaks. If we add saliva, we effectively fill in these valleys, and as a result have much more contact, meaning much more grip.
The concept is similar to the use of thermal paste for electronic equipment to draw heat away from some electronic component. While it seems like two solids put together are touching, on a micro-scale, this is rarely the case, unless the solid is very ductile, like a rubber band for example, which can bend and squeeze into gaps better than other materials. | [
"Saliva acts as a solvent in which solid particles can dissolve in and enter the taste buds through oral mucosa located on the tongue. These taste buds are found within foliate and circumvallate papillae, where minor salivary glands secrete saliva.\n",
"Saliva consists of proteins (for example; mucins) that lubri... |
how does the material on the other side of a sticker keep the glue sticky? | It doesn’t. The glue does in fact dry out (that’s why really old stickers have that crusty yellow stuff if you leave them out for a long time). However, if you’re referencing the waxy paper that the stickers originally come on, the wax paper allows the sticker to not be exposed to the surrounding air, therefor the water in the sticker’s glue doesn’t evaporate, the glue doesn’t dry out, and the sticker remains sticky. Over long periods of time, the glue will eventually dry out, but by preventing most of the sticker’s glue from being exposed to air, it can stay sticky for a much longer time. The reason the sticker can be removed from said wax paper is because the wax is hydrophobic (water isn’t absorbed by it) and so the glue stays to the hydrophilic part (water is attracted), or the glue itself. | [
"Pressure-sensitive tape, PSA tape, self-stick tape or sticky tape consists of a pressure-sensitive adhesive coated onto a backing material such as paper, plastic film, cloth, or metal foil. It is sticky (tacky) without any heat or solvent for activation and adheres with light pressure. These tapes usually require ... |
Why does a laser create a dark spot on phosphorescent material | Phosphorescence happens when an electron radiatively decays from a triplet excited state. This is different from fluorescence, which is the radiative decay from a singlet state. Doesn't matter what the real difference is, but triplet states are much longer-lived than singlet states (microseconds to seconds for triplets; picoseconds to a microsecond for singlet). The reason that phosphorescent materials can glow in the dark is that they hold onto the extra energy they get from absorbing photons as triplet state electrons, which decay a long time from when the photon was absorbed.
Electrons don't get pumped straight into the triplet state, usually. More likely a photon comes in and kicks a ground state electron up to a singlet state first. This singlet excited electron then has a chance to fall part of the way back down to the ground state but lands in the triplet state, which stalls it out for a while. This is called intersystem crossing. Later, that triplet excited electron will go back down to the ground state and emit a photon in the process, which is what we see as a glow in the dark. The probability of an electron making that singlet - > triplet transition is low; those that don't (i.e. most of them) will go from singlet - > ground state, which may or may not correspond to the emission of a photon. By pumping lots of ground state electrons into the singlet state (shining lots of light on the material) we can get some small fraction of lots of electrons into the triplet state.
The red laser pointer happens to have the same energy in each photon as the difference between the singlet and triplet states. This is the same energy it lost when the intersystem crossing happened, but we can put that energy back in and make the electrons go from triplet to singlet in a reverse intersystem crossing, opposite of what happened before. Now we have those electrons that used to be triplets in a singlet excited state and then down to the ground state very, very quickly (nanoseconds or so). So when you shine that red laser pointer onto your material you are moving electrons from triplet - > singlet - > ground quickly, getting rid of most of the triplet-state electrons that would yield phosphorescence, and leaving a dark patch in your material.
You could use this trick to, say, write your name in the material with the red pointer, read it in the dark later, and then erase it with a blue/UV light afterwards.
Or, say your material was fluorescent, too. The fluorescence is going to be much brighter because you can cycle your electrons from ground - > singlet - > ground much faster than ground - > singlet - > triplet - > ground. But if some significant fraction of your electrons keep getting hung up in the triplet state, you can increase your fluorescence output by, at the same time as exciting the fluorescence with, say, a blue laser, kicking those triplet electrons back into the singlet state with a red laser. You'd end up with more fluorescence output of your green-emitting molecules when the red laser was on. This increase in fluorescence is fast enough that you can use it to imprint a unique signal in the fluorescence intensity by varying the intensity of the red laser, then later filter your recorded signal by that known unique signal, which lets you filter out lots of noise and background. This is the principle behind this technique:
_URL_0_
TL;DR - the red laser resets the glow in the dark material back to the non-glowy state. | [
"Some examples of glow-in-the-dark materials do not glow by phosphorescence. For example, glow sticks glow due to a chemiluminescent process which is commonly mistaken for phosphorescence. In chemiluminescence, an excited state is created via a chemical reaction. The light emission tracks the kinetic progress of th... |
how do engines run at 5,000 or even 10,000 rpms? | Mainstream automobile engines usually redline at about 6-7k rpm. The reason they can spin so fast is because the crankshafts are perfectly balanced, and the pistons and rods are made to be as lightweight as possible. Also the journal jacking oiling system permits much higher spinning speeds than conventional bearings.
Diesel engines cannot rev as high as petrol engines because they are designed from heavier materials (for the extra power) so the inertia from the heavier components doesn’t allow it to spin as fast. (Without self destructing)
Imagine a record turntable, with a penny and a paper stamp at opposite edges. As the turntable speed ramps up, the heavy penny will fly off before the lightweight paper stamp. That’s the best analogy I can come up with at this time | [
"Given that the majority of engines for which a speed is defined rotate, engine speed is measured in revolutions per minute (RPM). Engines may be classified as low-speed, medium-speed or high-speed, but these terms are always relative and depend on the type of engine being described. Generally, diesel engines opera... |
why is it that in a country where you are not supposed to drink the water (india or china for example) it’s still ok to shower, brush your teeth, and even bath with it? | It's mostly a matter of amounts. You might drink a few litres of water a day but you won't swallow anywhere near that amount while brushing your teeth. And of course, toothpaste is there to help kill bacteria anyway. Bathing is less dangerous as it is far harder for bacteria to get into your system through your skin unless you have large wounds or bad burns. | [
"India and China are two countries with high levels of water pollution: An estimated 580 people in India die of water pollution related illness (including waterborne diseases) every day. About 90 percent of the water in the cities of China is polluted. As of 2007, half a billion Chinese had no access to safe drinki... |
Synergy of Aqua Regia? | It's all based on chemical equilibrium.
What happens is nitric acid does oxidize a tiniest bit of the gold to produce Au+3 ions and they're in a state of equilibrium; although this amount of dissolution would be negligible just by nitric acid itself, the hydrochloric acid serves as a source of chloride ions and allows the Au+3 ions to form Au(Cl4)- ions. The Au(Cl4)- ions are the dissolved "gold" ions you observe in a solution of aqua regia.
The gold keeps dissolving because the second equilibrium favors the formation of Au(Cl4)- ions, and this allows the Au+3 ions to be continually produced and the solid gold to be dissolved by the nitric to maintain the equilibrium. This "synergy" is indeed used in many different chemical processes.
tl;dr
Equilibrium of
Au+HNO3- > Au+3
Au+3+HCl- > AU(Cl4)- | [
"The exact underlying cause of aquagenic urticaria is poorly understood. , the main scientific ideas about the cause are that the person is reacting to tiny amounts of an unknown substance dissolved in the water, or that the water interacts with or combines with an unknown substance present in or on the skin, and t... |
Have we ever observed an object (such as an asteroid or comet) from another solar system come into our solar system? | We did for the first time last year
_URL_0_ | [
"Following claims by David Dunham in 1978 to have detected satellites for some asteroids (notably 532 Herculina) by examining the light patterns during stellar occultations, Van Flandern and others began to report similar observations. His non-mainstream 1978 prediction that some asteroids have natural satellites, ... |
What was ancient egyptian armor like? | The common protective item was the shield. These were often hide, and could be quite large:
* _URL_0_
* _URL_8_
The Egyptian word for "shield" also means "hide" or "skin" (Howard, 2011), so rawhide appears to have been the standard material. Wooden shield covered in hide were also used (2 of Tutankhamun's shields were covered in cheetah skin). From the New Kingdom onwards, shields were sometimes wooden with bronze faces and/or edges. Smaller round shields were also used:
* _URL_4_
These soldiers with round shields appear to be Sea People (Sherden), with perhaps one of them fighting in Egyptian service. There are no known examples of these shields in the hands of the Egyptian regular army.
Body armour wasn't common. When it was used, the most common body armour appears to have been scale. Scales of bronze, rawhide, and bone have been found. Sometimes, the armours are sleeveless, and only cover to the waist. Other armours are longer, and cover the thighs. Some armours had sleeves.
From the 2nd millennium BC, there are finds of scales
* Bronze scale with mid-rib, 1390-1353BC: _URL_7_
and, much more rarely, armour
* Sleeveless rawhide scale armour from the tomb of Tutankhamun: _URL_5_
and armoured soldiers appear in art. Armour, not being worn, also appears in art:
* Tomb of Kenamon (1436-1411BC): _URL_3_
Most soldiers in art have no body armour; the most likely to have armour are chariot soldiers. Interestingly, chariot horses sometimes appear to be armoured:
* _URL_2_
* _URL_6_
If this is horse armour, it would be textile armour (probably linen). It's possible that Tutankhamun's horse also has bronze scales attached.
Linen body armour was probably also used. There is no unambiguous evidence, but according to Howard (2011):
> One of the chambers in the Tomb of Rameses III (Structure KV11, chamber Ch) has a wall painting of a garment that could to be textile armour since it is accompanied by other weapons and armour. In his *Histories*, Herodotus attributes linen armour to the Egyptians, ...
Helmets are somewhat of a mystery, due to the lack of archaeological examples, and art showing helmets or possible helmets being difficult to interpret. Pharaohs are shown with a variety of headgear, but mostly things that don't appear to be helmets. Some art:
* _URL_1_
is sometimes interpreted as helmets (probably linen textile armour), but whether helmet or hat or maybe even just hairstyle isn't clear. These might be what Herodotus called "plaited" helmets. Bronze helmets might have been used by elite charioteers (with possible examples in art).
Reference:
Dan Howard, *Bronze Age Military Equipment*, Pen and Sword, 2011. | [
"Ancient Egyptian weaponry includes bows and arrow, maces, clubs, scimitars, swords, shields, and knives. Body armor was made of bands of leathers and sometimes laid with scales of copper. Horse-drawn chariots were used to deliver archers into the battle field. Weapons were initially made with stone, wood, and copp... |
why do the cfl lights remain dim & flash every few seconds even after being turned off? | I'm not sure about the flash, I've never seen it, but my guess would be the capacitors discharging. The after glow is the florescent coating exhibiting small phosphorescent qualities making it continue glowing in the same way a glow in the dark item still glows after exposure. Even old Tube TV s did this. | [
"Some CFLs will flash every few seconds even when the room light switch is off. This caused by a small amount of current bypassing the switch either through a switch pilot light or through the capacitance of the two conductor cable connected between the switch and the CFL or the capacitance between this cable and o... |
How do hydroelectric power plants produce electricity with a frequency of 50Hz/60Hz consistently? | Im an engineer but I will give you the answer. The hydroelectic plant is connected to the electrical grid, which has thousands of generators and loads on it. When you connect a generator to the grid your frequency is "locked" to the same frequency as everyone else connected. to increase or decrease your frequency you have to increase or decrease the frequency of the whole grid. its the same if you welded a bunched of engines together such that they turned the same shaft, to change speed all the engines would either slow or speed up. In that case if you control one of two engines its easy for you to stop apply fuel and drag the speed down if the other engine doesn't change its fuel input. However if there are 100 engines and you reduce fuel you probably won't even notice the change because you are such a small fraction of the total. Its the same on the electrical grid.
Now the reason they are all locked together is because we use AC synchronous generators. synchronous generators output AC at a frequency that is depended on speed.
Also you need to remember that its approximately 50/60Hz, not exactly. If you were to measure the frequency and plot it through the day you would see it go up and down over time. As load on the grid increases the frequency and voltage drop and when the load decreases the frequency and voltage increase. they combat this by increase the power output of generators to make sure there is enough production. | [
"BULLET::::- Electricity has a frequency of 50Hz; this is the typical frequency in Europe. In North America the frequency is 60Hz. This is assuming that there is a 1:1 correlation between rotational velocity of turbine and the frequency of mains power.\n",
"At the power station, an electrical generator converts m... |
why do americans generally not learn any second languages? | The same reason 90% of American citizens do not carry, have never carried and will never carry passports.
In other words, 90% of American citizens will never leave America... except maybe to go to Canada. Or the Bahamas on vacation.
Why? Put simply, because America is so goddamn big and has more than enough of *everything* to keep nearly everyone largely satisfied.
For many Americans, a trip to their state's Capital counts as a huge adventure. A trip to one of the big cities--NY, LA, Chicago--is a once-in-a-lifetime event.
Add to that a healthy dose of "AMERICA, FUCK YEAH!" attitude, which even the most enlightened of us carries deep down in our inmost hearts, and you've got a population who is perfectly content to stay home.
And if you never intend to venture out somewhere where they don't speak English, why bother learning anything but English?
This is not to say Americans are dumb. We aren't. We're just a bit sheltered by and naïve in our own ignorance and hubris, and we have so much of everything that anyone can find something to build their happiness around. | [
"In some countries, such as Australia, it is so common nowadays for a foreign language to be taught in schools that the subject of language education is referred to LOTE or Language Other Than English. In the majority of English-speaking education centers, French, Spanish and German are the most popular languages t... |
The AskHistorians Podcast - Episode 12 Discussion Thread - The Spanish Civil War | First of all, sorry about not being very good at being interviewed, this was my first time ever and I've never been amazing at speeches and saying things impromptu. Either way, if there are any questions I am happy to clear them up here (as will /u/Domini_canes, most likely), and I'll probably give a better answer in writing.
Also, I need to make a correction. In the podcast I mentioned that Companys was part of the Socialist Party. He was actually in the Republican Left of Catalonia, sorry about that, not sure how I slipped that one in.
Anyway, it was fun and I hope you enjoyed it too. | [
"The four stories are about the Spanish Civil War: \"The Denunciation\", \"The Butterfly and the Tank\", \"Night Before Battle\", and \"Under The Ridge\". Chicote's bar and the Hotel Florida in Madrid are recurrent settings in these stories.\n",
"Chapter II, \"The Spanish–American War\", is about the events of th... |
If our modern calendar begins with the birth of Christ, why isn't Christmas the start of a new year? | This is a long long story, going back to the founding of Rome in the 700s BC.
The very first Roman calendar (itself borrowed from the Greeks) had [ten months, starting with Martius and ending with December](_URL_5_):
1) Martius
2) Aprilis
3) Maius
4) Junius
5) Quinctilis
6) Sextilis
7) September
8) October
9) November
10) December
These months covered only 304 days of the year. The remaining 61 days, after December, were not part of any month.
Martius was the time of the Spring equinox, and [Spring was a common time for ancient societies to start their year.](_URL_3_) (However, it's not clear why the Roman calendar started about 21 days *before* the equinox.)
So, the original Roman calendar, from which our modern Gregorian calendar is descended, did start in Spring.
However, this 10-month year didn't last very long. Within about 50 years, two extra months were added to the year, to make it up to 355 days: Januarius and Februarius (the 10 missing days per year were made up every second year by a "leap month" of 20 days, known to the Romans as an "intercalary" month).
The Romans now had **two** beginnings to the year: Januarius was the month that each year's consuls started their year of service, but the calender year was considered to start in Martius. (This is sort of like the modern practice of having a financial year start on a different date to the calendar year.)
It wasn't until Julius Caesar's time, nearly 700 years later, that the New Year [was moved to the first day of Januarius](_URL_1_) (Caesar did this as part of his reform of the calendar, which became known as the Julian calendar).
The Julian calendar continued to be used in most of Europe long after the Western Roman Empire fell, but [with no consistency about when the start of the year was](_URL_1_) - it started on different dates in different countries: 1st March; 1st January; 25th March; even 25th December. (Even now, the English tax year starting on 6th April [reflects their previous New Year date of 25th March](_URL_6_), adjusted for the Gregorian calendar.)
Eventually, the confusion pushed everyone to consistency. This was assisted by the gradual adoption across Europe of the Gregorian calendar, with its New Year start date of 1st January (going back to Julius Caesar's earlier decision).
The current choice of January 1st is therefore based on Julius Caesar's earlier choice of this date, which was based on the fact that the month of Januarius "[contained the festival of the god of gates (later the god of all beginnings)](_URL_2_)".
***
From [here](_URL_7_). You may also be interested in the '[The year and months](_URL_4_)' section of the Popular Questions pages (as found in the sidebar).
***
I've found the same question [asked only 2 hours earlier](_URL_0_).
***
*EDIT*: I fixed the link for the 'The year and months' Popular Questions section.
| [
"Although the month and date of Jesus' birth are unknown, the church in the early fourth century fixed the date as December 25. This corresponds to the date of the solstice on the Roman calendar. Most Christians celebrate on December 25 in the Gregorian calendar, which has been adopted almost universally in the civ... |
why does rinsing my car with just the hose not remove dirt but leaving my car out in the rain does? | Probably because you don't wash your car with a hose for hours, if not a full day at a time | [
"Since 2012, nozzles are replaced on many cars by a system called AquaBlade, developed by the company Valeo. This system supplies the washing liquid directly from the rubber element of the wiper blade. This system suppresses visual disturbances during driving and so reduces the reaction time of the driver in case o... |
Do we need the van Allen Belts as a protection from radiation? | Van Allen belts are more like low points in the magnetic field where radiation settles, its not the belts themselves that keep us safe, but they are a product of the magnetic field which does indeed protect us from harmful radiation | [
"BULLET::::2. Missions beyond low Earth orbit transit the Van Allen radiation belts. Thus they may need to be shielded against exposure to cosmic rays, Van Allen radiation, or solar flares. The region between two and four Earth radii lies between the two radiation belts and is sometimes referred to as the \"safe zo... |
Circular polarized light, I don't get it | [Visualization](_URL_0_). Basically, the polarization vector of the light has to be 'rotating.' You can do this pretty easily [by putting a linear polarizer and a quarter-wave plate at an angle to each other.](_URL_1_)
That help?
> by say 45 degrees why isn't the output just light tilted 45 degrees rather than a continuously changing angle?
The filter itself isn't rotating, the vector goes up and down in a plane, and by sending that through a quarter wave plate at you can get the twist. | [
"There are several ways to create circularly polarized light, the cheapest and most common involves placing a quarter-wave plate after a linear polarizer and directing unpolarized light through the linear polarizer. The linearly polarized light leaving the linear polarizer is transformed into circularly polarized l... |
If the Mongols asked my town to surrender, and we did, how would we be treated? | This was asked just last week
_URL_0_ | [
"As the Mongols of the Ilkhanate continued to move towards the Holy Land, city after city fell to the Mongols. The typical Mongol pattern was to give a region one chance to surrender. If the target acquiesced, the Mongols absorbed the populace and warriors into their own Mongol army, which they would then use to fu... |
was it that knowledge of the Vikings' discovery of America didn’t spread or just that people didn’t realize the land they'd discovered was actually the edge of a giant continent so nobody viewed it as significant? if the former why didn’t it spread? | hi! It seems that knowledge *did* spread, at least in Greenland, Iceland, Denmark, England, & Germany. It would be fantastic if an expert could comment on what Europeans thought of Vinland/Markland/Helluland in terms of significance; meanwhile, here's a round-up of related questions so you can catch up with the discussion so far:
* [Is there any evidence that Christopher Columbus (and other 15th century explorers) knew of Lief Erickson's travels and the Viking settlements in the New World?](_URL_1_)
* [Did word of the New World discovered by Leif Ericson ever get to the Western Europeans?](_URL_4_)
* [Did the rest of Europe know about the Vikings' discovery of America?](_URL_0_)
* [Are any of the pre-Columbus maps of America real?](_URL_2_)
* [How did the Nordic countries react to the 1490-1500s New World discoveries?](_URL_3_) - i.e. versus what they already knew | [
"The 1874 book \"America Not Discovered by Columbus\" by Norwegian-American Rasmus B. Anderson helped popularize the idea that Vikings were the first Europeans in the New World, an idea that was all but verified in 1960. During his appearance at the Norse-American Centennial at the Minnesota State Fair in 1925, Pre... |
Has there ever been a rich country that has become a poor one and stayed poor? | Sorry, we don't allow ["trivia seeking" questions](_URL_0_). These tend to produce threads which are collections of disjointed, partial responses, and not the in-depth discussions about a particular topic we're looking for. If you have a specific question about an historical event, period, or person, please feel free to re-compose your question and submit it again. Alternatively, questions of this type can be directed to more appropriate subreddits, such as /r/history /r/askhistory, or /r/tellmeafact. For further explanation of the rule, feel free to consult [this META thread](_URL_1_).
Just a suggestion, but you might want to consider focusing on the 20th century, perhaps South America's relative economic decline during the past century. | [
"His best known book, \"How Rich Countries Got Rich ... and Why Poor Countries Stay Poor\" (2007), has been widely reviewed and discussed. While some reviews, like those in Prospect Magazine, The Economist, and others were dismissive many – including those from the developing countries – were positive and even thos... |
how does it work for two headed creatures? do they sense things independently? how is the nervous system controlled? do they have diminished intelligence? | I think it depends on where the sever is... if they share a brain, they will not sense, think, or feel things independently. However, if their brains are completely separate they will process thoughts separately; if their heads are the only thing they have two of they will share other neurological and biological systems, and so they will feel the same things (unless the brains process the nervous signals differently, which is unlikely). Since they have separate brains, they will likely learn and adapt to situations similarly but not identically, so they could end up having very different personalities and thought processes. | [
"The nervous system is generally similar to that of gastropods. One pair each of cerebral and pleural ganglia lie close to the oesophagus, and effectively form the animal's brain. A separate set of pedal ganglia lie in the foot, and a pair of visceral ganglia are set further back in the body, and connect to pavilio... |
If you took a pill that contained an entire meal's worth of nutrition, would you still feel hungry after it was digested? | How big would a pill be that contained that many calories and nutrients? Even if made entirely of dehydrated stuffs, wouldn't it also expand in your stomach. | [
"It should be taken on an empty stomach, one half to one hour before food, as absorption is reduced when taken with food, though some studies suggest that this doesn't compromise flucloxacillin plasma concentrations in most circumstances. \n",
"BULLET::::- Not eating causes one form of unhealthy snacking. Evelyn ... |
how does workman's compensation work? | I answered how rates are set in another reply. I'll now address the what happens if you are working from home part.
This is an incredibly murky area of work comp right now, and tends to be extremely variable case by case. For example, I recently saw a claim where an employees house caught on fire while they were working from home and they had smoke inhalation injuries. The fire was started by the employee putting something on the stove and forgetting about it (because they got caught up in their work again). Is this a work comp claim? This will almost certainly be considered one, but if the circumstances were slightly different it would be challenged. Honestly, if this was a bigger claim than it is the carrier would probably try to fight it.
So, the simple answer to your question is if you are hurt while you are in the process of performing work while at home or anywhere else, it is a work comp claim. In a mixed work/living situation it would be on the carrier to argue your claim that it wasn't covered. | [
"Workers' compensation (also known by variations of that name, e.g., workman's comp, workmen's comp, worker's comp, compo) offers payments to employees who are (usually temporarily, rarely permanently) unable to work because of a job-related injury. However, workers' compensation is in fact more than just income in... |
How did the female vote alter the political landscape? What new policies were shifted or enacted to accommodate the new base? | hi! Could you specify which region/country/culture you're asking about? Also, if you don't get answers here, it might be worth x-posting this question to /r/AskSocialScience | [
"With some exceptions, many countries expanded women's voting rights in representative and direct democracies across the world such as the United States, Canada, Great Britain and most major European countries in 1917–1921, as well as India. This influenced many governments and elections by increasing the number of... |
why does drinking alcohol make you tired? | Alcohol interferes with the actions of glutamate and NMDA, two key excitatory compounds that stimulate/regulate activity in the nervous system. They’re sort of like natural stimulants that keep things moving. Alcohol can inhibit the activity of their systems, but it also supports the activity of GABA, the main inhibitory neurotransmitter in the body.
Increasing the activity of GABA is like stepping on the breaks while you’re driving.
Because alcohol affects the entire brain, it will also work on systems of wakefulness and alertness in the nervous system. | [
"Alcohol is often used as a form of self-treatment of insomnia to induce sleep. However, alcohol use to induce sleep can be a cause of insomnia. Long-term use of alcohol is associated with a decrease in NREM stage 3 and 4 sleep as well as suppression of REM sleep and REM sleep fragmentation. Frequent moving between... |
If we can't put anymore transistors on a microchip because the transistors are physically too small, why don't we just make bigger microchips? | they can make them larger...but that wont make them faster. Think of it like this....you work downtown....you live within the city center...you commute to work. The city becomes increasingly crowded and people move further from the city center....and their commute to work is longer and longer the bigger the city gets.
thats a chip with the same scale
now imagine if the public transit system of your city could double its speed with a new higher power engine...if you could do that it would be AS IF the city was half the size....commuters would speed to work.
In the microchip world instead of increasing the size of the engine in the train....they seek to shrink the city. But at this point the way we know buildings (transistors) doesnt allow us to shrink them much more....so unless someone figures out how to build smaller houses, or faster roads.....
Bigger chip = more processing at the same speeds. Essentially without some breakthrough in microchip technology.....the new path forward becomes parallel computing. Our current multicore processor computers are rarely given dynamic multithreaded tasks....most software is single thread. So it would require a paradigm shift in programming but....thats likely the future...
at least as far as I can tell. | [
"As it becomes more difficult to manufacture ever smaller transistors, companies are using Multi-chip modules, Three-dimensional integrated circuits, 3D NAND, Package on package, and Through-silicon vias to increase performance and reducing size, without having to reduce the size of the transistors. \n",
"As more... |
do people have "brain prints"? people have unique finger prints, eyerises, and DNA, do we have unique brain structures aswell? | The short answer would be yes. The longer answer would be that the neurons in your brain form in a way unique to you, however the human adult has around 100 billion neurons, so making a "print" of this would be extraordinarily difficult. | [
"Most scientists working on the relation between the human brain and neurologic or psychiatric diseases (or animal models of these diseases) use Paxinos's maps and concepts of brain organisation. His human brain atlases are the most accurate available for identification of deep structures and are used in surgical t... |
why is michael jackson considered the "king of pop?" | Because he redefined pop culture.
He was the first black musician who broke through the color barrier on MTV. He made MTV a definitive TV channel. Before Thriller was released the music industry was in a crisis, Thriller legitimately helped save it. At one point Thriller was selling 1.4 million albums every 4 days and had sold over 30 million worldwide only 1 year after its release. It's now sold somewhere between 75-100 million and about 32 million just in the US alone, and still ranks in the top 200 albums sold every year in the states where it's selling 140k a year 30 years after it's release. He made music videos compulsive viewing. He is the reason that musicians use group dancers. He's the reason urban dancing is mainstream. He started touring as part of the Jackson 5 aged just 5 years old. He signed on to Motown at the age of 9. He released his first single aged 11. He is the reason the Superbowl half time show is now a thing. He wrote and helped choreograph most of his own pieces. His iconography is huge - you think of a sequin glove, sequin jacket, military jackets, armbands, fedora, surgical mask, loafers, moonwalk, lean, spin to the toes, a dip of a hat and you think of MJ, there aren't any other musicians who have such a wide and immediately recognizable iconic pieces. He donated $300 million to charity in his lifetime. Every single pop musician since Michael Jackson is inspired in some way by him, even if they don't realize it, because what he did is the standard now. He created the benchmark and template for what it is to be a modern pop musician. | [
"Michael Joseph Jackson (August 29, 1958 – June 25, 2009) was an American singer, songwriter, and dancer. Dubbed the \"King of Pop\", he is regarded as one of the most significant cultural figures of the 20th century and one of the greatest entertainers. Jackson's contributions to music, dance, and fashion, along w... |
What was the actual incident of Karbala in the history of Islam? | I can give you a more detailed answer this weekend, but very briefly, there aren't two opposite versions. Contrary to popular belief, Sunni's are not (nor ever were) anti-Ali. Both Sunnis and Shi'ites consider the events of Karbala to be a massacre of the family of Muhammad.
That said, due to the central importance of family and lineage in Shi'ism, Karbala has a much more prevalent role and thus you'll find, on average, more Shi'ites talking about Karbala than Sunnis. | [
"The arrival of envoys from Muhammad in 632 heralded the conversion of the region to Islam. After Muhammad's death, one of the major battles of the Ridda Wars was fought at Dibba, in present-day Fujairah. The defeat of the non-Muslims, including Laqit bin Malik Al-Azdi, in this battle resulted in the triumph of Isl... |
what is going on over at /r/punchablefaces? | /r/punchablefaces is a ~60k community that posts... punchable faces.
However, in order to comply with reddits strict no harassment policies, they have had to implement a few rules:
* No black, brown, tan, Asian, Latino, Native North or South American, or Pacific Islander subjects
* No LGBTQ subjects
* No subjects with disabilities (physical, developmental, or any other type)
* No women or non-binary subjects
* No underage or elderly subjects
* No socioeconomically disadvantaged subjects
Some have pointed out that these rules mean its only okay to post straight, cisgendered, able bodied, middle class, white males and that therefore they are discriminatory themselves.
This point has been taken on board and has resulted in [this](_URL_0_) being the only allowed image on the sub, as someone that represents the spirit of the rules without targeting any one race or sex directly. | [
"\"FaceBreaker\" has a \"cartoony\" artistic style (similar to \"Punch-Out!!\" and \"Ready 2 Rumble Boxing\") and allows players to break their opponents faces as the game features \"real-time facial deformation\". The game also uses the same face-capture technology as \"Tiger Woods PGA Tour\" to allow players to c... |
where does all the dirt from power washing go? | It's floating in the water kicked off by the power washer.
It then usually flows with the water down into the drain. | [
"Laundry was first done in watercourses, letting the water carry away the materials which could cause stains and smells. Laundry is still done this way in the rural regions of poor countries. Agitation helps remove the dirt, so the laundry was rubbed, twisted, or slapped against flat rocks. One name for this surfac... |
after an android device installs an update it will spend some time optimizing apps. what, exactly, is happening during this process? | _URL_0_
> When you install an application on Android, it performs some modifications and optimizations on that application's dex file (the file that contains all the dalvik bytecode for the application). It then caches the resulting odex (optimized dex) file in the /data/dalvik-cache directory, so that it doesn't have to perform the optimization process every time it loads an application.
When you update the operating system, it might install a new version of Dalvik (the actual software that runs the Android apps), or there might be new optimizations for this version of the OS, so the optimizations need to be performed again. | [
"In May 2019, with the announcement of Android 10, Google introduced Project Mainline to simplify and expedite delivery of updates to the Android ecosystem. Project Mainline enables updates to core OS components through the Google Play Store. As a result, important security and performance improvements that previou... |
When Eratosthenes was calculating the circumference of the Earth in the third century BC, what did he calculate or scrawl on? Papyrus, wax, sand? | Papyrus or parchment. We now know, thanks to Wadi al-Jarf, that papyrus was being used in Egypt as early as the reign of Khufu (c.2550). By the time of Eratosthenes in the 3rd century BCE, it was common (but not cheap) and reasonably easy to acquire anywhere in the Mediterranean. Parchment was another alternative, and the Hellenistic kingdom of Pergamon (in western Anatolia) was famous for its production. There is a legend that the Ptolemy dynasty in Egypt monopolized papyrus use and did not allow their Hellenistic rivals elsewhere to use it. This is not generally considered to be true, however.
Wax tablets were a cheap alternative for non-permanent record-keeping, though I do not know how much they were used in the Hellenistic world. They were common in the Roman world. Lead sheets were also used as a form of paper, again because they were cheap, but they were difficult to inscribe and hard to read. We find them a lot in use as cheap personal letters and as a medium for curses. | [
"Eratosthenes, a Greek astronomer from Hellenistic Cyrenaica (276–194 BC), estimated Earth's circumference around 240 BC. He had heard that in Syene the Sun was directly overhead at the summer solstice whereas in Alexandria it still cast a shadow. Using the differing angles the shadows made as the basis of his trig... |
why the usa are (or have been) at war in the middle east. | "They pull a knife, you pull a gun. He sends one of yours to the hospital, you send one of his to the morgue. That's the Chicago way."
~ The Untouchables
Also related:
"I can hear you, the rest of the world hears you, and the people who knocked these buildings down will hear all of us soon."
~ George W. Bush | [
"The Middle East is, of course, the most obvious place that comes to mind when we think of valuable resources that major nations may compete over when supplies begin to fall around the world. The first Gulf War was an example of the United States’ willingness to go to war to protect its access to the rich oilfields... |
why does drinking alcohol with an empty stomach cause one to get drunk quicker? | It means the alcohol gets into the bloodstream quicker as it's processed quicker. Don't know the ins and outs and technicalities but that's the gist.
Correct me if I'm wrong, Reddit. | [
"Mixing alcohol with normal soft drinks, rather than diet drinks delays the dizzying effects of alcohol because the sugary mixture slows the emptying of the stomach, so that drunkenness occurs less rapidly.\n",
"Ouzo can colloquially be referred to as a particularly strong drink, the cause of this being its sugar... |
if you could know the state of subatomic/quantum particles, could you calculate the future? | There seems to be a degree of randomness inherent in quantum physics. To the best of our understanding the answer to your question is no. | [
"In classical mechanics, accurate measurements and predictions of the state of objects can be calculated, such as location and velocity. In the quantum mechanics, due to the Heisenberg uncertainty principle, the complete state of a subatomic particle, such as its location and velocity, cannot be simultaneously dete... |
Is it possible to consume too much Vitamin C in one day? | Vitamin C has laxative effects at high dosages | [
"Vitamin C is a water-soluble vitamin, with dietary excesses not absorbed, and excesses in the blood rapidly excreted in the urine, so it exhibits remarkably low acute toxicity. More than two to three grams may cause indigestion, particularly when taken on an empty stomach. However, taking vitamin C in the form of ... |
How does a pane of glass "become" a mirror when there is a strong contrast in lighting on either side? most prominent at night time with the lights on inside | Glass reflects around 4% of the light incident on it, with the lights on inside this 4% is much brighter than the darkness outside. | [
"The glass is coated with, or has encased within, a thin and almost-transparent layer of metal (usually aluminium). The result is a mirrored surface that reflects some light and is penetrated by the rest. Light always passes equally in both directions. However, when one side is brightly lit and the other kept dark,... |
Broad prehistory/anthropology question: Which do you view as more relevant in motivating a move from a hunter-gatherer society to an agricultural society... (see text) | I think that your perspective is a bit off, but then the anthropological perspective is very different from most peoples' and takes a lot of reading and lectures to really start to grasp, so your perspective is pretty much par for the course.
For one, the idea that agriculturalists are somehow better than hunter-gatherers is very much a modern idea that comes out of 18th and 19th century thought. Before that most people probably had no idea that there was such a thing as hunter-gatherers, and even in marginal places where agriculturalists (farmers, pastoralists, or horticulturalists) lived beside hunter-gatherers, it isn't likely that they saw each other as being another class of people who did things incredibly differently, they were just other people, another ethnicity, who did whatever they did.
But you also can't think of it as a hunter-gatherer group sitting down and thinking 'ok, let's see, we can keep hunting-and-gathering, or we could start farming. Farming is likely to increase our food yield by a factor of X. Let's do it!' These were very gradual, evolutionary changes that took place over the course of millennia. In Levant, for instance, we think that people were cultivating things (tending wild plants to help them grow better, but not true agriculture) by at least 12,000 BP whereas things weren't domesticated until maybe 10,000 BP (cultivation is incredibly tricky to see archaeologically, so there's necessarily a lot of speculation). After the [broad-spectrum revolution](_URL_0_) ca. 20,000 BP people gradually began to manage their food more and more until things were eventually domesticated. At first this was small-scale, incipient agriculture, but in time larger fields were planted, irrigation canals were dug, etc. to increase yields. It wasn't an overnight decision, it was something that took a very long time and any one person probably didn't know that they were doing anything differently than their parents, or grandparents, or great-x10-grandparents, or whatever.
Now, that is for the 7-10 places where agriculture was invented independently. When agriculture spread conceivably people would have looked at it and decided to accept or reject it, but it was still a gradual thing.
But more than anything it is worth understanding the evolutionary perspective (social evolutionary theory tends to be very strong with anthropological archaeologists like myself). Evolution doesn't have an end-goal, it isn't about progress, or imagining some utopia future and striving for it. It is descent with modification, and adapting to best survive in the current environment. Agriculture didn't take off because people saw the possibilities in it; it took off because the people who practiced it were able to have more kids that survived long enough to have their own kids. There *must* be some reason why it was independently invented numerous times over a relatively short period (about 3000 years from first to last), and why it spread everywhere. But we don't know specifically why it was invented and spread, and any answers you get will tell you as much about that person's theoretical background as it will about early agriculture.
So that's one anthropologist's approach. This really isn't a history question, so I'd ask this at /r/anthropology or /r/AskSocialScience to get more responses. | [
"Lepenski Vir gives us a rare opportunity to observe the gradual transition from the hunter gatherer way of life of early humans to the agricultural economy of the Neolithic. More and more complex social structure influenced the development of planning and self-discipline necessary for agricultural production.\n",
... |
neoconservatism vs. neoliberalism | When they combine they make neo-fascism. | [
"\"Neoliberalism\" is contemporarily used to refer to market-oriented reform policies such as \"eliminating price controls, deregulating capital markets, lowering trade barriers\" and reducing state influence in the economy, especially through privatization and austerity. It is also commonly associated with the eco... |
How did German soldiers view Canadians during WW2 | This isn't an answer to the question but a related piece of information, because I figure you'd be interested in how Canada was seen more generally in this era. At Auschwitz, the warehouses that held the luggage and possession stolen/confiscated from newly arrived inmates were known as "Kanada". I've always assumed this name originated with the prisoners themselves, but I'm unsure of that; what I do know is that these warehouses got their name because Canada was seen as a "land of plenty". From [an online glossary dealing with the Holocaust](_URL_0_):
> **Kanada** (in German, or usually **Canada**)
> On arrival at the ramp in the East, all arriving prisoners were told to leave their larger pieces of luggage. In reality, the luggage they had so painstakingly packed was taken on arrival at Auschwitz to a series of special warehouses known collectively as "Kanada." Initially, all prisoner clothing and hand luggage was stored in a warehouse in block 26 in the main Auschwitz I camp. However, by mid-1942, there was so much looted property that storage was moved to six barracks near the main camp Auschwitz I for storage. [...]
> *Kanada, the Birkenau warehouses where the belongings of the newly arrived victims were sorted and stored by the SS, had a special meaning in Poland. In Poland, the name and country Kanada symbolized a place of great riches, and as such, it is still used as an idiom for wealth in contemporary Poland.* At Kanada, prisoner labor would open and sort the contents of the luggage for reutilization in the German war economy. This included clothing, personal possessions like hair brushes and tooth brushes, and eventually also byproducts of the killing process: such as, dental gold and human hair (used as fleece linings in military jackets). Also known as Effektenlager. | [
"The Canadian Forces and civilian participation in the First World War helped to foster a sense of British-Canadian nationhood. The highpoints of Canadian military achievement during the First World War came during the Somme, Vimy, Passchendaele battles and what later became known as \"Canada's Hundred Days\". The ... |
why can't clicking the x to close a program in windows act in the same way as clicking end task from a ctrl+alt+del? | Clicking "X" *asks* the program to shut down. Using the task manager *forces* the program to shut down by just ignoring it and unloading all of its data from memory.
When you shut down a program, you want to ask it nicely, because it may have some stuff to do--saving files, closing connections--that could potentially corrupt some files if not done properly. | [
"BULLET::::- xkill - if called without any parameters, the mouse cursor changes from an arrow to an \"x\" icon, and the user can click on a window to force the X server to close the connection with the client owning the window. This often causes the process to terminate when it detects that its connection to the X ... |
what is diminishing returns? | Imagine I gave you a chocolate bar. You'd be pretty happy, right? It's tasty.
Now, imagine you had a hundred chocolate bars, and I gave you one more. You wouldn't gain as much happiness from that additional chocolate bar, because it doesn't let you do as much in the way of new things. That's diminishing returns. | [
"The law of diminishing returns states that in all productive processes, adding more of one factor of production, while holding all others constant (\"\"ceteris paribus\"\"), will at some point yield lower incremental per-unit returns. The law of diminishing returns does not imply that adding more of a factor will ... |
Why were there so many Kolechian attacks on Arstotzka (particularly the East Grestin) border in December 1983? | Although, as you say, East Grestin is POLITICALLY recognised as Arstitzkan territory, there was a lot of nationalist sentiment lingering in Kolechia, especially amongst the ethnic Grestians in the population, who believed that, as East Grestin was originally Kolechian, it should remain Kolechian. They did not recognise the validity of the Paradizna Agreement, signed by Kolechia and Arstotzka to end the border war of 1937, which gave Arstotzka East Grestin, while Kolechia gained some smaller territory that was, however, richer in raw materials.
As for the status of the Order, it is said that the Order was merely the pschological warfare (or "psy-ops") branch of the terrorist organisation, and were intended to sow discord amongst members of the Arstotzkan border control agency. | [
"Starting in late 1991, when the Azerbaijani side started its counter-offensive, the Armenian side began targeting Azerbaijani villages. According to Memorial, the villages Malibeyli and Gushchular, from which Azerbaijani forces regularly bombarded Stepanakert, were attacked by Armenians where the houses were burne... |
why do probiotics sometimes cause diarrhea, gas, or other symptoms of ibs? | Probiotics and antibiotics can both affect the amount of 'flora' (helpful bacteria) that live naturally inside your gut. Part of what those bacteria do is help digest things and create important chemicals that the body uses. Bacteria can act almost act like an organ in our body. Cows, for example need gut bacteria to be able to eat grass. We have different bacteria than cows, so we don't get the luxury of eating grass as food.
Gut bacteria unsurprisingly have some interaction with our immune system, whose favorite pastime is inflammation. Changes in flora can coincide with changes in inflammation, such that flora can ultimately decrease gut inflammation. But since the body keeps things in a delicate balance, periods of transition can be irritating.
Regarding gas, bacteria utilize a process called fermentation, which chemically results in gas bi-products (carbon dioxide, methane).
Ultimately, increasing or decreasing the amount and/or balance of natural bacteria in the gut can cause other changes in response while a balance is being achieved. | [
"Probiotics may exert their beneficial effects on IBS symptoms via preserving the gut microbiota, normalisation of cytokine blood levels, improving the intestinal transit time, decreasing small intestine permeability, and by treating small intestinal bacterial overgrowth of fermenting bacteria.\n",
"Certain probi... |
what would happen to astronauts in orbit if earth instantly disappeared? | They would continue in a "straight" line from their current trajectory. Away from the former position of the planet. | [
"Upon returning to Earth, the empty spacecraft burns up due to a faulty (separated) heat shield during atmospheric reentry. The astronauts are said to have died due to the malfunction. The captive astronauts board a plane to be placed in the spacecraft, but the plane unexpectedly turns around and returns to the air... |
How far are we away from economical synthetic/In vitro meat? | HI!
I'm going to have a rant here about *in vitro* meat.
First off, this shit comes up every few months on reddit, and the massive response is always really positive, and everyone looks forward to 2020, or 2050 or whatever magical date that is proposed to be the date when this shit is cost-effective.
Let me burst that bubble. My background is biotech, which is where this kind of meat would end up, in the science world. In Biotech we grow lots of meat already, in massive, 10,000 litre vats that make tons of incredibly expensive medicines. We tend to use CHO cells, which are Chinese hamster ovary cells. They are great! I worked with them a lot, and they are basically one of the most retard-proof mammalian cells in the world.
OK, so what are the problems facing artificial meat?
* Cost of raw materials
* Manufacturing scale
* Lack of benefit
**First** the cost. We can make cheap "meat" with fungus or whatever. People want 'real' meat though, which means mammalian cells. Which means very tricky growth. They have no cell wall, are delicate, and as the most efficient way to grow them is to use vats, they need a lot of careful aeration and feeding. Small scale is relatively easy, although you make very few cells. Large scale, massive costs, massive problems. Forget about antibiotic free meat for a start, you can't have large scale without tons of antibiotics, foam reducers and other 'chemicals' that would curdle the toes of your average meat eater.
Another, and to me the major unspoken point, is FBS/FCS. Foetal calf serum, foetal bovine serum. Mammalian cells don't grow well without it. You either mince up baby cows and give the juice to the cells (see the redundancy?), or you spend insane amounts of money on very costly Swiss artificial sera which don't work very well.
**Secondly** you have manufacturing scale. Have you, dear reader, ever grown mammalian cells and forgotten them in a T-flask? And then you go in and find a massively over-confluent sheet of flesh at the bottom of the flask? A slice of Henrietta Lakcs? That is what the goal is, and to make a full steak you need a BIG flask or vat. And to make enough meat to replace the meat industry, or even make a dent, you need a MASSIVE biotech industry to spring up. **INSANE** capital costs. And the problem with that capital cost, is the problem number 3...
**Thirdly**, is lack of a benefit. The problem is, cows are cheap. Cheap to look after, ridiculously so compared to growing cells. Every single piece of the cow is used, everything is sold and nothing, not even the shit, is wasted. While mammalian cell growth is as wasteful as hell. Cows make a ton of meat cells, with an **excellent** defence against infection, while mammalian cell growth is as touchy as fuck about aeration dead spots, shear forces, infections or whatever.
The search for *in vitro* meat is a **great** search. I worked on a project for an artificial liver once, it is another one of those '2050' projects, but on that journey we will learn so much that we can use now. This search for an artificial steak is like that, it's a way to learn a lot about the whole field. However, the picture of a guilt-free steak they show you is just the hook for funding, imho.
And to the inevitable retorts about how we will overcome these problems with future technology, please remember this is an industry that is currently worth absolutely ZERO. The recombinant protein industry is worth more than Africa. (**edit**, I checked and it's only around a tenth of the value of Africa, my bad, sorry Africa). If we got these problems sorted, it wouldn't mean a triumph for steak, but for Factor VIII. The two dudes working in a university lab, who are always quoted with these stories, aren't going to be breaking out the perfect serum free media, it's going to be Pfizer or whatever.
Sorry to be a balloon popper.
**edit**
Just to add one more take on this!
The thing is, Cows are excellent at turning the raw materials of water and grass, into meat. We want the meat. So we want to skip the cow bit. Meat is cells, and they want the raw materials to go through a lot of digestion. The entire premise here is that we somehow jump over all that digestion. We want to take cheap raw materials, and somehow make the cells eat that shit. The alternative, which is what we do now, is to get cows to eat it, take their blood, mix it with really expensive, really pure chemicals that cost tons, and give it to the cells.
So what we want, is to either make cells that can deal with cheap raw materials, or make some machine that can turn grass or sugar beats or whatever, into blood, more or less.
Hopefully, putting it that way makes it obvious that what we are after here, if we had it, would be massive. Cheap meat-in-a-vat would be a tiny detail compared to the technology we would be wielding in that future. | [
"The production of cultured meat is currently very expensive – in 2008 it was about US$1 million for a piece of beef weighing – and it would take considerable investment to switch to large-scale production. However, the In Vitro Meat Consortium has estimated that with improvements to current technology there could ... |
what's so bad about (us) debt collectors? | You're correct. Only issue is that occasionally debt collectors try to collect on debts that aren't legally your responsibility. | [
"According to the Federal Reserve Bank of New York's May 2017 Quarterly Report on Household Debt and Credit, Americans owe $12.73 trillion in consumer debt to creditors—credit card companies, student loans, mortgages, and car dealers, among others. These debts are usually paid off to creditors, but by 2017, unpaid ... |
why was it better for swords to only have one edged blade (like the katana or falchion)? | Swords were designed for various purposes. Double edged blades were used to impale or stab the opponent. Whereas katanas are curved and one sided to provide a better slicing motion.
The shape of the blade provides structural strength. To simplify, the cross section of a katana would resemble a triangle. Impacting a triangle on a point would distribute the force and stop the blade from breaking. | [
"The sharpened edge is the inward curved, longer side of the blade – the opposite of a standard katana – making it extremely difficult to kill an opponent; it generally knocks the wielder's enemies \"senseless\" rather than killing them. The only way for the sakabatō to cut is to rotate the hilt by 180 degrees with... |
Why does some salt taste saltier that other salt? | Salt's saltiness can be affected by many different factors. The composition and purity of the salt in question, the concentration of the salt, and persistence of the salt on the tongue all make up each different salt's taste.
This article sums up the complexities of salt and taste in relatively simple terms. _URL_0_
As for your specific question, salt packets vs. a new jar of flaky kosher salt, I would imagine that the extra saltiness you're experiencing from the flaky kosher salt is a result of a) the purity\quality of the processed kosher salt, and b) the physical composition of the kosher salt vs. that of the salt packet (read: usually kosher salt has larger 'grains' of salt allowing for you to experience a continuing level of saltiness as the mechanical digestion of your teeth further pulverize the salt into smaller and smaller pieces allowing for a prolonged salty sensation, whereas the salt from the packets dissolves almost instantly, without mechanical breakdown, thus its' saltiness sensation is much shorter lived.) | [
"Because the salt has a purer flavor due to the lack of metallic or bitter-tasting additives such as iodine, fluoride or dextrose, it is often used in the kitchen instead of additive-containing table salt, so such flavors are not introduced to prepared food. Estimating the amount of salt when salting by hand can al... |
What were cocoliztli and matlazahuatl, and how did these epidemics affect indigenous and colonial communities? | I have not researched matlazahuatl, but cocoliztli is now considered to be a viral hemorrhagic disease akin to our modern [Hantavirus](_URL_1_). Several [recent studies](_URL_0_) have linked the 1545 and 1576 Mexican epidemics, which burned through Mexico and killed anywhere from 7 to 17 million people, to multi-year droughts preceding the epidemics. The balance of evidence suggests the virus was indigenous, and not introduced to the Americas after contact. To the best of my knowledge, there is not a lot known about the interaction of the virus with human hosts in Mexico before contact. Perhaps the changing ecological conditions, combined with social upheaval and overall degradation of Native American health through introduced infectious diseases, food stress, and displacement allowed the virus to jump more readily to human hosts and spark novel epidemics of a previously contained pathogen. | [
"There exists some ambiguity regarding if \"cocoliztli\" preferentially targeted native people, as opposed to European colonists. The majority of firsthand accounts regarding the outbreak come from Aztec informants, who were primarily concerned with the diseases’ novelty and pronounced symptoms. Spanish colonizers ... |
why is it so difficult to find video highlights of football/soccer games? | Because of very strict control of (very expensive) TV rights. Rights owners know filter images and videos by the droplet. | [
"Video servers, with their advanced technology, have allowed for more complex replays, such as freeze frame, frame-by-frame review, replay at variable speeds, overlaying of virtual graphics, instant analysis tools such as ball speed or immediate distance calculation. Sports commentators analyze the replay footage w... |
where the fuck were these lonely mountain dwarves in lotr when every one of their allies was battling sauron? | Remember in the movies when frodo gets caught in that mini landslide and two evil men check out the area? Notice that those guys are heavily armored: they are not the same people that ride the elephants during the siege of minas tirith.
Heavy Armor = Men of Rhun (north of mordor)
Elephant Dudes = Men of Harad (south of mordor)
In the books, an army of 200,000 soldiers from Rhun descends on the reconstructed Dale (which was repopulated between the Hobbit and LOTR). The people of Dale take refuge in Erebor (the dwarf kingdom in the mountain) and besiege the mountain. When Sauron is defeated in the south, the men of Rhun lose morale and the forces of dale and erebor take the opportunity to strike the besieging army and rout them.
Legolas alludes to these events happening very briefly on their way to finding the undead army in the mountains. | [
"The Dwarves of the Lonely Mountain (also known as Erebor) and the Men of Dale refused to acknowledge the overlordship and alliance of Sauron. While his larger southern armies invaded Gondor, a host of Easterlings advanced in the north to extend his dominion and to prevent the armies of his enemies joining together... |
how do they make weed killer that they can spray on grass and plants that only kill weeds without hurting the grass or plants? | There are two major families of flowering plants, called dicots and monocots. There are a lot of subtle differences between them, but one of the easiest ways to tell is the [shape of the leaves](_URL_0_) EDIT: and the way the veins are arranged
Grasses and almost all grain crops, like corn, wheat, and rice, are monocots. Most "weed" species are dicots. The most common types of weed killers only kill dicots, and leave monocots unharmed.
Other types of weed killers will kill almost all plants, but they've genetically engineered certain crops to be resistant to that weed killer. If you've planted those genetically engineered crops, you can spray the weed killer all over your field and only the things you don't want growing will die. | [
"Herbicides are used to kill weeds, especially on pavements and railways. They are similar to auxins and most are biodegradable by soil bacteria. However, one group derived from trinitrotoluene (2:4 D and 2:4:5 T) have the impurity dioxin, which is very toxic and causes fatality even in low concentrations. Another ... |
How big does an object have to be to have color? | First of all, the color of an object is not an intrinsic property. The color of the light that comes from an object to your eye could result from many different mechanisms. For this reason, an object can have many different colors depending on how it generates or scatters light. For instance, nitrogen gas that is creating light via gas discharge (somewhat like a Neon sign) is pink, while the nitrogen gas that is the main component of the atmosphere is typically blue because of Rayleigh scattering. Similarly, iron at room temperature is black/gray, but heat it up a bit and it glows orange without its molecular structure changing at all. "Object color" is an emergent phenomenon that arises from a particular mechanism involving the interaction of light with electric charge in a material, or from the transition of electric charge in a material. Object Color is the result of a particular process, and not an intrinsic property.
With that in mind, a single atom can indeed have a color, but it depends on what mechanism you are talking about to describe what that color is. The simplest mechanism for a single atom to emit light is through an electron transition. For a particular isolated atom, only certain transitions are allowed, and therefore only certain colors can be emitted. These colors form a characteristic emission line spectrum which is like a fingerprint for an atom. By looking at the color spectra of distant stars and comparing it to atomic spectra we measure in the lab, we can deduce what atoms the distant stars contain.
But a simple electron transition/line emission is not the only way that an atom can emit or scatter light. Rayleigh scattering is another mechanism by which a single atom can scatter/emit light, and the mix of colors in Rayleigh scattering is different than that produced by line emission. There are also many other scattering mechanisms. So it's not like isolated argon atoms are always purple. It depends on how the light is being produced.
In summary, yes a single atom can display color, but the color depends on the exact mechanism involved. Note that the light from a single atom is very weak. You typically need the light from a lot of atoms to register something. But if the atoms are in a dilute gas, they act mostly independently so that the colors from a dilute monatomic gas are similar to the colors you would get from a single atom of the same type. [Take a look at the photos on the right of this webpage](_URL_0_). These photos give a good idea of what color a single atom of a certain element would look like under line emission if we could photograph them. | [
"Colour indices are simple measures of the differences in the apparent magnitude of an object seen through blue (B), visible (V), i.e. green-yellow, and red (R) filters. The diagram illustrates known colour indices for all but the biggest objects (in slightly enhanced colour).\n",
"These ten objects are fabricate... |
In WW2, how exactly did technological transfer from Germany to Japan take place and how did Japan pay for it? | For the most part, technology and trade in raw materials between Germany and Japan occurred through individual blockade-runners. In exchange for examples of German military technology and plans, the Japanese provided raw materials and other items the Allied blockade prevented from being imported to Germany. From the outbreak of the war to around 1942, surface ships formed the bulk of inter-Axis trade. Of some 104,232 tons of raw materials shipped from East Asia to Europe in 1941-42, approximately 75,000 tons arrived in European ports. The Germans and their Italian allies did not make the most of this brief lifeline and the items ordered from Japan included non-essential materials like tea and coffee and cooking oils. Although these raw material helped ease domestic shortages, it exemplified the skewed and myopic priorities of Italy and Germany. The nature of industrial warfare necessitated a more ruthless prioritization, especially given the acute shortages of strategic materials like rubber and tungsten. This short-sightedness came to a fore by 1942 when Allied naval superiority was able to cut the surface blockade-running lines with ease. Although there were tentative steps towards an aerial connection between East Asia and Europe, the only practical option for the Axis to run the blockade was submarines. German Type IX U-boats could carry at best 2-3% of the tonnage of a surface blockade-runner and the larger Japanese submarines were only slightly better. The inability of the European Axis to prioritize their brief window of opportunity in 1941-42 of building up stockpiles of East Asian raw materials led to persistent shortfalls of these materials in the German war economy and their substitution by inferior ersatz ones.
Payment for this exchange was a source of consistent tension within the alliance. The Japanese would pay for German plans and examples of technical equipment with raw materials supplemented by gold, but the Germans would seldom agree on the Japanese exchange ratio for these goods. The disagreement over payment and equitable exchange spilled over into operational matters. The Kriegsmarine ordered the commanders of the Monsun Gruppe of U-boats based in Malaysia to hide the existence of the newly-developed acoustic T-5 homing torpedo from their Japanese hosts or give them an explanation of its technical workings. German industrial firms also expressed grave reservations about handing over plans and other industrial information without first getting guarantees of honoring German patents. There were a few notable instances of fruitful collaboration, such as in 1943 when Luftwaffe general Erhard Milch circumvented the Kriegsmarine and approached the IJN attache Abe Katsuo if the IJN could ship tungsten in exchange for plans for radio-controlled bombs and examples of Luftwaffe autocannon. The IJN agreed to this transfer and the submarine I-29 delivered the tungsten to Lorient in March 1944 and Milch provided the equipment as payment in kind without hassling over the exchange ratio.
But this type of cooperation was the exception rather than the rule and the inter-Axis trade relationship was characterized by mutual distrust, skewed priorities, interagency rivalries, and miscommunications.
*Sources*
Krug, Hans-Joachim. *Reluctant Allies: German-Japanese Naval Relations in World War II*. Annapolis, Md: Naval Institute Press, 2001.
Militärgeschichtliches Forschungsamt. *Germany and the Second World War Volume VI, The global war: widening of the conflict into a world war and the shift of the Iniative 1941-1943* Oxford: Clarendon Press, 2001.
| [
"In the years leading up to the outbreak of World War II in Europe in 1939, there was some significant collaborative development in heavy industry between German companies and their Japanese counterparts as part of the two nation's evolving relations. This was one major factor in Japan's ability to quickly exploit ... |
what's the difference between ssris and saris? | SSRIs bind to transporters that clear serotonin out of the synaptic cleft. Depending on how selective the specific SSRI in question is, it may or may not have some effect on dopamine and norepinephrine transporters.
& nbsp;
SARIs have similar action on transporters as SSRIs, with the additional effect of "hitting" serotonin receptors and possibly dopamine receptors, depending on the specific drug. I used the vague term "hitting" because they act as partial agonists (activating the receptors), antagonists (preventing activation of the receptors by serotonin) and inverse agonists (specifically inactivating the receptors).
& nbsp;
The mechanism for how these binding and activation effects produce the physiological effects is not well understood. | [
"Serotonin antagonist and reuptake inhibitors (SARIs) are a class of drugs used mainly as antidepressants, but also as anxiolytics and hypnotics. They act by antagonizing serotonin receptors such as 5-HT and inhibiting the reuptake of serotonin, norepinephrine, and/or dopamine. Additionally, most also antagonize α-... |
why do mini m & m's taste so much better than regular m & m's? | I'm going to go with the crunchy outside to chocolate ratio. | [
"\"USA Today\"s Ted Berg said \"they’re not good\" but also \"not totally awful\" either. \"Kotaku\"s Mike Fahey said \"pleased to report that Mac n’ Cheetos taste much better than they look\" but also that they do not taste like the cheese puff but rather like the Kellogg's cracker Cheez-It. \"Chicago Tribune\"s J... |
semiconductors | The key principle is the "band gap". According to classical physics, if you have an electron in an atom, you can give it just a bit more energy. And that "little bit" can be any value. But that's not how things actually work. Since electrons have to obey the laws of quantum mechanics, the electrons in an atom can only inhabit certain energy states. This can lead to what is called a band gap.
Assuming you know a little more chemistry and physics than your typical 5 year old:
The outer electrons on an atom are called "valence electrons", and their energy level is the "valence band". (It's a "band" because it is a range of values, not just one number.) Electrons with more energy than the valence electrons are no longer tightly bound to individual atoms, and they can move around fairly freely within the material. They are said to be in the "conduction band" of energy. When a substance has a lot of electrons in the conduction band, the electrons can move around quite a bit if given a good reason to, like an electric field (a voltage). We call those materials good conductors of electricity.
In most metals, the valence band and conduction band actually overlap, so they have plenty of electrons in the conduction band and can conduct electricity well. In insulators, there's a big energy gap between the two bands...you have to provide a lot of energy to get any of the valence electrons to jump up into the conduction band. The energy levels in-between the two bands aren't allowed due to quantum mechanics. So insulators are crappy conductors of electricity. There simply aren't any electrons with the freedom to move around.
Semiconductors (like Si, Ge, GaAs, etc.) have a small band gap. Since there is a gap, they normally don't conduct electricity well, just like insulators. But if you can give the electrons a bit of energy to jump up into the conduction band, they are fairly decent conductors of electricity. This is why they are called *semi*conductors.
It turns out that it is also possible to "tune" the band gap of semiconductors by introducing some atoms of another material (a "dopant"). And it is possible to get electrons over the small band gap by supplying a voltage. So by doing some band-gap engineering, it is possible to construct structures that will either conduct or not conduct using very small voltages or currents to control their conductivity. We call those structures "transistors".
Silicon has a lot of physical properties that make it preferable to other semiconductors. It can easily be oxidized, making an insulating layer. It is cheap and plentiful. It can be "grown" into large single crystals that are relatively defect free. It has fairly good thermal properties. Because of these reasons and others, a huge body of knowledge has been developed about how to make circuits using silicon as the main component, and make those circuits cheap, reliable, and high performance. Sometimes Si won't do all of those things well (like very high frequency devices, or lasers), so other materials are used instead. | [
"The study of semiconductors is a significant part of materials science. A semiconductor is a material that has a resistivity between a metal and insulator. Its electronic properties can be greatly altered through intentionally introducing impurities or doping. From these semiconductor materials, things such as dio... |
Why are anti-rejection drugs needed permanently for transplants? | The answer to your question is inherent in your understanding of transplants and immunology. The one flaw in your reasoning is:
> organs regularly require constant regeneration by the host body
Transplanted organs do have cellular turnover, and they are supplied **nutrition** by the host body. The organ itself replenishes its own cells with its own DNA.
The reason we keep transplant recipients on long-term immunosuppression is to avoid rejection of the transplant. We do in fact need to 'trick' the recipient's immune system into overlooking the fact that there is foreign tissue in their body.
Our bodies recognize foreign cells by proteins called **major histocompatibility complexes**. There are 2 types, each with specific immune cells that recognize them. We choose donors based on how closely these complexes match the recipient: the closer the match, the less likely rejection will occur. We use immunosuppression to decrease the sensitivity of the recipient to these matched (but still foreign) MHCs.
Matching donors to recipients is 100% necessary before we can move forward with a transplant. Tom **can** have Jim's liver and Jim's liver will continue to regenerate with Jim's DNA. | [
"One principal reason for transplant rejection is non-adherence to prescribed immunosuppressant regimens. This is particularly the case with adolescent recipients, with non-adherence rates near 50% in some instances.\n",
"In the United States it is frequently given at the time of the transplant to prevent graft-v... |
Why are trucks, and not trains, the main method of freight transportation in the U.S.? | Without getting at all into the history of how it developed, it isn't clear to me that your premise is correct that trucks are the main method of freight transport in the US.
According to the [US Department of Transportation](_URL_0_), 39.5% of freight ton-miles in the US are rail vs. 28.6% via truck (12% water, 19.6% pipeline and 0.3% air.).
| [
"Although railroads have lost much of the general-freight-carrying business to semi-trailer trucks, they remain the best means of transporting large volumes of such bulk commodities as coal, grain, chemicals, and ore over long distances. The development of containerization has made the railroads more effective in h... |
why is sitting close to a monitor for long periods bad for your eyes as apposed to looking at brickwall for a long period | You're focusing at the same distance for hours on end day after day. The muscles in your eye will hold at that focus and tire. RSI.
| [
"When the eyes dry out or become fatigued due to reading on a computer screen, it can be an indication of Computer Vision Syndrome. Computer Vision Syndrome can be prevented by taking regular breaks, focusing on objects far from the screen, having a well-lit workplace, or using a blink reminder application such as ... |
what the differences between micro and molecular biology | Microbio is like...cell to cell interactions. It's on the level of cell organelles in humans, cells interacting with each other in small colonies, that kinda thing. It's usually interested in viruses, bacteria, etc.
Molecular bio is like protein/molecular interaction level. It's closer to biochemistry in that you're looking at smaller objects than microbio, usually in the context of inside of a cell or inside of an organelle. | [
"A biomolecule or biological molecule is a loosely used term for molecules and ions present in organisms that are essential to one or more typically biological processes, such as cell division, morphogenesis, or development. Biomolecules include large macromolecules (or polyanions) such as proteins, carbohydrates, ... |
Not sure if this is more "Ask Historians" or "Ask Science" but, essentially, how did pre-industrial civilizations move water uphill? | There was the [Archimedes Screw](_URL_0_), which has been around since at least the 3rd Century BCE. Also, you should read the first couple sections on fountains, [here], (_URL_1_) where it explains how Romans used gravity to create pressure down the line. Finally, I know the Mayans created water pressure by channeling water from a higher source into a piping system that grew narrower and narrower. Once in these pipes, the water pressure increased to that point that the flow of water could overcome gravity. I'm no expert, but I assume that most of these pre-industrial hydraulic systems gained much of their pressure from starting at an elevated location (mountain springs, aqueducts, etc.) before being channeled into pipes | [
"A pragmatic, if not scientific, knowledge of fluid flow was exhibited by ancient civilizations, such as in the design of arrows, spears, boats, and particularly hydraulic engineering projects for flood protection, irrigation, drainage, and water supply. The earliest human civilizations began near the shores of riv... |
a mongooses immunity to cobra venom | Your nerves are covered in protein receptors that function like little locks. They also produce proteins, called neurotransmitters, that function like little keys which perfectly match the keyhole that the receptors have. When the correct neurotransmitter goes into a receptor, it "twists" and briefly causes a small hole to open up in the cell. This hole allows a small amount of electrolyte into the cell, which causes the cell to briefly turn on.
To prevent the cell from staying on perpetually, it has enzymes that break neurotransmitters down shortly after they enter a receptor. This causes the hole to close so electrolytes stops flowing in. The cell, meanwhile, is constantly pumping electrolytes out. Now that electrolytes can't flow in, electrolyte levels in the cell go back to normal and it turns off.
Cobra venom contains a protein that fits into the "lock" on one of the important protein receptors on animal nerves. However, despite fitting the lock, the cobra venom protein doesn't twist so no hole gets opened and the nerve doesn't activate. The cobra venom protein is also different enough from the normal neurotransmitter that the nerve cell can't break it down. This means that the cobra venom protein just sits in the protein receptor without doing anything - blocking it from being used by neurotransmitters.
If enough of this protein gets into an animal's body, it blocks all of that animal's neurotransmitters. When all of an animal's neurotransmitters are blocked, its nervous system turns off. When an animal's nervous system turns off, it stops breathing and dies.
Mongooses are immune to cobra venom because they have protein receptors with a very slightly different keyhole shape than other animals. That keyhole is still similar enough that the mongoose's neurotransmitters can fit in it to function normally. However, its also different enough that cobra venom now just slightly doesn't fit. Because the cobra venom can't get into the mongoose's protein receptors, it doesn't have an effect on the mongoose. | [
"The Samar cobra's venom is a potentially deadly neurotoxin, with cytotoxic properties as well. Envenomations can result in respiratory distress and paralysis, as well as considerable tissue necrosis around the bite site. They are noted for their nervous behavior, and are quick to strike as well as to spray venom, ... |
Is it possible to acquire AIDS from something other than HIV? | The key to answering this question lies in the final S of AIDS, which stands for [syndrome](_URL_0_). A syndrome is what doctors call a set of symptoms that seem to go together, even if they don't know what's causing it. Often these syndromes turn out to have an underlying disease or other cause.
So for example in the early days of the AIDS crisis, doctors noticed that certain patients had similar symptoms, namely that they suddenly developed (that's the A for acquired, as in it wasn't a genetic thing they'd had all their lives) severe immuno-deficiency (the ID, their immune systems became very weak). Eventually HIV was identified as the causative agent for the syndrome that the doctors had observed.
So the answer is that you can get similar symptoms from a variety of other problems, but AIDS refers to a very specific set of symptoms that tended to develop together under specific set of circumstances. Actually, many of my coworkers refer to it as "HIV disease" since you can be infected with HIV and not have the symptoms that would classify as AIDS. | [
"We Are Not A Cure For AIDS: False information would have you believe that having sex with a person with albinism will cure AIDS. In truth, no one has ever been cured of AIDS by having sex with a person with albinism. All this does is spread the AIDS virus.\n",
"The origin of AIDS has been linked to a virus known... |
WTC 7: How did this fall down (at free fall acceleration) from fires? | This is an exact duplicate of a question that was [submitted yesterday](_URL_0_). Please use the search feature or skim the new queue to avoid submitting duplicate questions. | [
"Soon after 10pm, as night was falling, Amon's Ferrari suffered a puncture while running 5th. Because of a faulty mallet he could not change the tyre out on the track and while crawling back to the pits, sparks from the wheel hub started a fire in the engine. Amon was forced to bale out quickly (unharmed) at a dist... |
Is modern-day veterinary medicine better than the medical science of the 1860s? | Yes!
No question about it.
You can find a lot of old vet books at [Internet Archive](_URL_0_) to see what they practiced then. You can find equally old medical (human practice) books.
At any period, vet practice does not lag much behind human medicine, if at all. We're talking about saving valuable property here, especially in race horses. If they are giving horses draughts of ammonia, odds are you will find the same thing being administered to humans (one of the treatments for the Spanish flu listed in, I believe, Henley's Formulas). I recently got a 1937 home medical encyclopedia, and found that mercury and lead doses were still in use as antibiotics, alongside sulfa drugs.
My husband was doing some research on veterinarians recently, and he found that the demands of vet study often make going to med school instead look easier by comparison. Your modern vet can treat any disease that shows up in both humans and a domestic animal species, like diabetes or cancer, and can treat trauma just as well, whether the patient weighs half a ton or half a pound.
In fact, in the 1860s, medical "science" is getting a bit stupid. You know how the role of citrus fruits in combating scurvy was discovered in the later 1700s? Thanks to the shortening (in days) of ocean voyages, and improvements in land dwellers' diets, scurvy was becoming kind of rare in the 1860s. So a certain French surgeon managed to promulgate the idea that scurvy was just a form of ptomaine poisoning brought on by improperly preserved foods. This lack of ascorbic acid in their foods helped kill a certain number of Antarctic explorers, like Scott, in *1912*. So I certainly wouldn't want an 1860 MD if I could have a 2015 veterinarian treat me. | [
"As science and technology developed, medicine became more reliant upon medications. Throughout history and in Europe right until the late 18th century, not only animal and plant products were used as medicine, but also human body parts and fluids. Pharmacology developed in part from herbalism and some drugs are st... |
How has the discipline of History evolved over time? In other words, what is the history of History (from Herodotus to monotheism to the enlightenment to postmodernism, etc)? | This is a *massive,* massive question, one far bigger than I suspect the sub is prepared to answer.
What you're asking about is called the discipline of **historiography** -- in other words, the history of how history is studied and told. As a quick little guide to it, I'm fond of [John Arnold's *History: A Very Short Introduction,*](_URL_1_) which is a fairly common introductory text in many universities' history programs, but if you're restricted to online resources for the moment, [Wikipedia's entry](_URL_0_) actually isn't bad. | [
"Understanding the past appears to be a universal human need, and the telling of history has emerged independently in civilizations around the world. What constitutes history is a philosophical question (see philosophy of history). The earliest chronologies date back to Mesopotamia and ancient Egypt, though no hist... |
why do our energy levels go down when we're depressed? | Depression in many ways puts your body through the same processes that a lot of physical illnesses do. One part of that is that both are associated with the release of what are called pro-inflammatory cytokines in your body. Like the name implies, these are chemicals that cause inflammation in your body. Evolutionarily speaking, what humans and other animals do when they are sick is retreat and rest. They retreat because they are weak and wouldn’t be able to defend themselves against enemies. They are fatigued because their body is fighting off whatever is making them ill, and sleep more to reserve their energy. A lot of other stuff can happen here as well, but essentially your body shuts down everything that is not necessary for your immediate survival (sex drive? being able to solve super difficult sudokus? you don’t need that right now!) Collectively these are called sickness behaviors, and they developed because they are adaptive for your survival. Only with depression things get a little trickier because there is no obvious virus or bacteria to fight off. But essentially you’re body is confused but trying to help the best it can: it can hear the alarm bells ringing, and the alarm signal sounds a lot like being physically injured. | [
"Another way depression increases an individual's ability to concentrate on a problem is by reducing distraction from the problem. For example, anhedonia, which is often associated with depression, decreases an individual's desire to participate in activities that provide short-term rewards, and instead, allows the... |
Is it possible to magnetically levitate an object with total freedom of rotation? | Perhaps like [this](_URL_0_)?
What's going on here is diamagnetism. When certain materials are exposed to magnetic fields, they generate their own field that opposes the direction of the applied field. This opposing field then repels the applied field, creating levitation.
The trick is that you need very, *very* powerful magnets to get this to work. The ones in the video are around 16 teslas, and a typical fridge magnet is around 0.005 teslas, for comparison. | [
"Spin-stabilized magnetic levitation is a phenomenon of magnetic levitation whereby a spinning magnet or array of magnets is levitated via magnetic forces above another magnet or array of magnets, and stabilised by gyroscopic effect due to a spin that is neither too fast, nor too slow to allow for a necessary prece... |
Was Charles V's title Emperor or King of Spain? Why was he not king of Hungary-Croatia and Bohemia? | Regarding 1.
Kingdom of Hungary and Croatia were never parts of the HRE, and Charles V was **never** their king nor emperor.
After disastrous battle of Mohacs in 1526, where king of Hungary and Croatia died, their respective noblemen held congress to elect their kings.
Without complicating the fact the nobility was divided between two candidates, the Croatian nobles *Sabor* (parliament) in Cetingrad in 1527 elected directly archduke **Ferdinand** as king of Croatia. So not Charles.
The same was pretty much in Hungary, in the rump diet of Bratislava where Ferdinand, not Charles, was elected king. But there the situation was even more divided, and outside my knowledge range.
| [
"Charles V, Holy Roman Emperor, or Charles I of Spain, was the heir of four of Europe's leading royal houses. Charles was the first sole monarch of Spain, inheriting the kingdoms first united by his maternal grandparents, Isabella I of Castile and Ferdinand II of Aragon (the Catholic Monarchs). From his father, Phi... |
Is my newish car more fuel efficient in a warm summer or cold winter? | The air is definitely denser but either your car injects more fuel to keep the mixture constant or it doesn't and the mixture will be off, but there will be more air to totally burn the fuel, which should happen in a well tuned engine anyway. I don't know which of these happens, but I think best case there is you have the same fuel input. Gasoline does contract in cold weather and I also dont know if your car accounts for this. The big problem arises with the much lower temperatures, not just the air but of your engine too. Your engine is designed to run efficiently at some relatively high temperature and the longer it takes to 'warm up' the less efficient it will be. For shorter trips this effect is more pronounced. As for the air being colder this means it has less enthalpy to begin with, so you will be adding more in and getting less out.
All in all your car will be much less efficient in cold weather. My car gets about 28 MPG in summer and 26 MPG in mild winter if the roads are clear.
Thats another thing I didnt mention, if you live where theres a lot of snow, obviously having to plow through snow will hurt your fuel economy. Most cars get best mileage at 55 MPH and winter drivers are often slower so that will hurt you as well.
TL;DR winter sucks | [
"Newer designs are focused on using super-insulated cabins which can heat the vehicle using the body heat of the passengers. This is not enough, however, in colder climates as a driver delivers only about 100 W of heating power. A heat pump system, capable of cooling the cabin during summer and heating it during wi... |
On Youtube's home page, there is a seemingly robust algorithm that shows suggested videos (aka What to watch) based on your watching habits and subscriptions. Why does it include mostly videos I have already seen? Doesn't that totally defeat its purpose? | I don't have any inside information for how youtube works internally, but having just spent all night trying to solve similar technical challenges (on a much smaller volume), I can take a guess: scaling is hard. Even for youtube engineers with google money to burn.
First, you can often serve content to several orders of magnitude more users if that content is identical for all users. This is because serving a copy of the completed page as one object out of a cache is so much cheaper than rebuilding the page by first gathering (possibly) hundreds of different components across disks and databases, and then running it through hundreds or thousands of lines of code to calculate the result.
Youtube clearly doesn't serve the same front page to all users, but even caching components of it, and caching across similar users can massively reduce their cost and complexity.
Second, just considering the database alone, the query required is slow and difficult to properly design for exactly the reason you say-- the sheer number of videos versus users. In general, databases can perform very well looking up information from one table with an index.
For example, youtube can say "Give me rizlah's email address" from the user account table, and although its still difficult to do this quickly for millions of users, its "relatively" quick and easy. But as soon as you want to "join" information from "rizlah's past views" with "suggested views for this video" it is far more difficult.
But it isn't impossible. And I agree with you, I'd like to see a websites do a lot better. Especially netflix... where the total number of videos and views is so small.
| [
"When watching videos outside of Wikipedia, many people go to Wikipedia to get more information about what they watched and proceed into the wiki rabbit hole to topics progressively further removed from where they started.\n",
"Unlike other online platforms such as YouTube and Facebook, which use trained algorith... |
Why does a neutron destabilise a uranium atom? | There is a big difference in relative stability between U-235 and U-236. It is similar to standing on a cliff - at the top, you have a lot more potential energy than someone standing at the bottom.
Fission occurs when the nucleus breaks up into 2 parts. These pieces, on their own, are much more stable than the original nucleus. But a barrier exists between these two states (otherwise U-235 would spontaneously fission). In other words, if you give enough energy to the nucleus, it can overcome this barrier and undergo fission.
Any big nucleus can be split with a neutron, but the catch is that, for most isotopes, the neutron has to have a ton of energy to overcome the barrier between the original state (big nucleus) and the final state (2 pieces).
So the reason why U-235 is "special" is that there is such a big energy difference between U-235 and U-236. When U235 absorbs a neutron, it's like getting shoved off the cliff of potential energy - suddenly you have a U236 nucleus with a bunch of extra energy. This energy is enough to induce fission (i.e. it doesn't require any extra energy from the neutron). In other words, U-235 can fission even with neutrons of extremely low energy. | [
"In a mass of pure natural uranium, the number and energy of the neutrons being released through natural decay are too low to cause appreciable fission events in the few U atoms present. In order to increase the rate of neutron capture to the point where a chain reaction can occur, known as criticality, the system ... |
why is it not a good idea to give people who are starving as much food as they want? | It's called refeeding syndrome.
Essentially, their entire body has gone into starvation mode that is optimized for survival under conditions of extreme food shortage. Minerals such as phosphate, magnesium and potassium are already extremely low throughout the body, but to keep the body alive the concentrations in the blood is kept at normal levels. When overfeeding a starved patient, this changes.
When you suddenly feed then, it signals the body primarily through insulin to start an immediate high uptake of glucose, amino acids etc. from the blood. Because of the way these nutrients are usually processed in biological pathways, and demands inside the cells, this consumes phosphate and potassium (fun fact: A treatment for having too much potassium in the blood can be to administer insulin and glucose) to a degree that can be life threatening as they are pulled from the blood to meet demands in the cells.
We absolutely need these minerals and molecules to function. ATP which is the most active energy transport molecule contains phosphate and using this up in a period of starvation can be disastrous. As for potassium, a low concentration in the blood can trigger a heart attack. It also triggers a fall in blood calcium due to increased cellular activity.
In simply terms, you run the risk of killing these people by moving essential factors from the blood to the cells when they're already critically low.
Therefore you need to monitor the blood chemistry closely and not overfeed patients who have been starved for long periods, including extremely anorexic patients. | [
"Throughout history, the need to aid those suffering from hunger has been commonly, though not universally, recognized. The philosopher Simone Weil wrote that feeding the hungry when you have resources to do so is the most obvious of all human obligations. She says that as far back as Ancient Egypt, many believed t... |
how a waiter can lose money if someone doesn't tip | This as commented on yesterday. But basically there appears to be several factors.
1) Waitstaff are paid at below minimum wage, as government assumes tips and thus they factor in tips to their minimum wage levels. Ex. In Ontario minimum. Wage is 10.25 I believe, wait staff are paid 7-8 from the business, rest is from tips.
2) Of their tips they are required to share with bus staff, bar staff and even kitchen and Management staff, though management taking a cut is frowned on. This is simply done by assuming everyone tips, and taking 3-5 percent of the bill total for those staff. Also they add I was told 10% of total value of the bill to their pay stub for income and unemployment taxes. They biggest visible on hit is that bar bus pool, but in a busy restaurant a server can see their base pay eaten by the assumed tip wage of 10% total food served.
So bottom line, servers live off tips and not getting tips does cost them. | [
"BULLET::::- Tipping is not expected and some employees may not understand the gesture and return the money. Some employees are forbidden from accepting gratuities (this is mainly in positions of authority e.g. in a casino one cannot tip the dealer or a security guard however, this would not apply in a formal resta... |
Is life decreasing or increasing the total entropy in the universe? | We are always increasing entropy. It's not so much a physical law as it is a statistical law.
A dorky example my secondary school chem teacher once gave us. If our room is a giant mess, we can say in some loose way that the entropy of the room is large.
So, we decide to clean up our room and make it neat and tidy. Since things are now nicely ordered, we might think that "Hey, I've decreased the entropy of the room, things were disordered at first, but I've intervened and things are looking better".
But, what we haven't taken into account is that to clean up our room we needed a bunch of energy. The way we got this energy is by breaking up sugars (which are a very specific form) and broken them apart (more entropy added). More than that, we may have worked up a bit of a sweat and our bodies heated up. This heat radiates from our body and heats up the room (more entropy). Even though we cleaned our room and seemingly made things more ordered, we still actually increased the overall entropy in the universe.
Try using this as an excuse the next time your SO makes you clean something up. **YOU** don't want to be responsible for the heat death of the universe **do** you??
I'm sorry if this is a stupid example, but it has always stuck with me! | [
"The role of entropy in cosmology remains a controversial subject since the time of Ludwig Boltzmann. Recent work has cast some doubt on the heat death hypothesis and the applicability of any simple thermodynamic model to the universe in general. Although entropy does increase in the model of an expanding universe,... |
why is it that sitting for extended periods can cause blood clots but laying down sleeping for 6-8 hours a night doesn’t? | When you sleep your blood does not have to flow upwards, your body is mostly straight and you are still moving alot in sleep. So If your leg is broken and you can't move a little your chance developing cloths is higher. That's why they give you shots in hospital every day. While sitting the legs aren't moved much, they are angled and the blood have to flow upwards. | [
"This disease is caused by problems in the circulatory system, so when it is presented, in the beginning it is important to follow several recommendations. The person needs to keep the legs elevated as much as possible to help the return of the blood. Whenever sitting down, the person needs to keep the legs on a fo... |
Does distilled water still contain ions? | Yes. Even in the absence of influences that might induce self-ionization in water a certain proportion of the molecules will have enough energy to break an oxygen-hydrogen bond to produce a hydroxyl anion and whatever protonated water is thought to be these days. The amount of molecules able to ionize is related to the temperature and only becomes zero at absolute zero, so self-ionization will always happen to some degree. | [
"Few ion-exchange resins remove chlorine or organic contaminants from water – this is usually done by using an activated charcoal filter mixed in with the resin. There are some ion-exchange resins that do remove organic ions, such as MIEX (magnetic ion-exchange) resins. Domestic water purification resin is not usua... |
Is there a minimum and maximum 'speed' of time? | We also use the speed of light as a reference point for the maximum speed of time. Think of all objects as moving at the same speed. Objects that you and I observe as being stationary are moving at the same speed as an object moving at 0.999c. The difference is that non-moving objects are moving entirely in the temporal dimension, and objects moving near c are almost not moving temporarily.
Short version, the speed of time is the inverse of the speed of light. | [
"Both for human and artificial intelligence, hardware improvements increase the rate of future hardware improvements. Oversimplified, Moore's Law suggests that if the first doubling of speed took 18 months, the second would take 18 subjective months; or 9 external months, whereafter, four months, two months, and so... |
how do i get fruit flies when i wash my produce when i bring it home and don't leave the window open? | I'm assuming you mean Drosophila melanogaster (_URL_0_) or one of its relatives as opposed to other fruit fries (if you are referring to the agricultural pest, they may come from eggs laid in fruit). These flies likely get into your house via small holes in the exterior, cracked or opened doors (even just while someone is entering/leaving), or other small openings. Houses, especially older ones, aren't known for being airtight enough to keep out small insects. | [
"Fruit flies are attracted to ripened fruits and vegetables, usually in the kitchen area, but will breed in garbage disposals, empty bottles and cans, wet or damp mops or cleaning rags, and trash containers. The only requirement for these flies to breed is a moist film of fermenting material. Infestations can origi... |
When was the last time 2 ships fired broadsides at eachother? | The last time a battleship fired on another battleship was at the Battle of the Surigao Strait, Oct. 25, 1944. The American forces had six battleships: *California, Pennsylvania, Maryland, Mississippi, Tennessee*, and *West Virginia.* They fired at night on a Japanese force that had already been badly damaged by torpedo attacks from US destroyers, using radar to find firing solutions. Of the U.S. battleships, only *Pennsylvania* was unable to find a firing solution. *Mississippi* only found one at the end of the engagement and fired the last salvo from a battleship against a heavy ship in history. The Japanese battleship *Yamashiro* was sunk and heavy cruiser *Mogami* was crippled, without returning fire.
The last engagement in which both sides fired at each other was the Battle of the North Cape, in which the German *Scharnhorst* was sunk by HMS *Duke of York.* That battle took place on Dec. 26, 1943.
**Edit:** Spelling. | [
"The term is commonly used to describe the firing of broadsides by warships, especially battleships. During fleet engagements in the days of sail, from 17th century until the 19th century, ships of the line were maneuvered with the objective of bringing the greatest possible number of cannon to bear on the enemy an... |
What is the difference in environmental impact between a new car and a used car? | Short news piece with numbers [here](_URL_0_) (unfortunately, original article unavailable).
Summary (trusting their numbers): making a new Prius costs 1,000 gallons of gas. A Prius (45mpg) would have to drive ~16,000 miles to catch up to a 12mpg used car whose manufacturing costs are already paid off. A higher-mpg used car (say an old civic, mine's 30 mpg) would take 90-100K miles.
| [
"The car allowed a shift in residential locations, as civil engineering grew to handle the infrastructure requirements, allowing the growth of the suburbs. As shown by Ford, the car changed the economic landscape. The efforts to resolve costs that have ensued from the influence of the car, such as pollution and fue... |
how does my body know which muscle i'm telling it to flex, or limb i want to move? | This is the most simplistic way I can think of to explain this; your brain has connections between neurons called synapses. Synapses carry electrical signals across neurons and parts of the body move based on the intensity and frequency of these signals. When you "want" to move something, the synapses fire in the part of the brain that controls that something and signals are sent from the brain, through the nerves in your body to the muscles in order to move that something.
So basically, you actively select which part to move (unless you have a muscular disorder such as chorea) and your brain will fire neurons in that area of your brain. The same thing happens when you are touched but in reverse. A stimulus activates nerves where you are touched and those nerves communicate to the part of your brain "in charge" of that body part.
I hope that helped! It's a complicated process!
Edit: Spelling because I didn't pass 5th grade English. | [
"BULLET::::- Skeletal muscle: Contraction of these muscles leads to the muscle pulling a tendon, which in turn pulls a bone. Moving a bone results in either flexing or extending a joint. Skeletal muscles are usually arranged in pairs so that they oppose each other (they are \"antagonists\"), with one flexing the jo... |
why bacon is seen as a manly food and seen as the best food ever? is it it's high calorie and fat content that makes it extremely palatable to humans? | Because its tastes delicious. | [
"\"Bacon Today\" states that bacon has a very valuable amount of protein that is \"valuable to maintaining our energy levels and a fully functioning, healthy body\". \"Everything Tastes Better with Bacon\", a book by Sara Perry, is a cookbook that compliments bacon's many uses in cooking.\n",
"On the subject of b... |
Can we determine, solely by examining the ear of an animal, the range of frequencies that the animal can hear? Or, how much more information do we need? | Good question. I don't think there is anything about the outer ear morphology that you can look at and then guess what frequencies an animal can hear, but I may be wrong. However, it's fairly easy to determine the range of frequencies an animal can hear and there are many methods to do it. For example, you can put some electrodes on the animal's head and one down in their ear very close to their cochlea, then send a click into their ear. The electrodes will register the electrical activity of the cochlea and auditory nerve in response to the sound. If you do a frequency analysis of the signal recorded by the electrodes it will show the range the animal's ear is able to respond to.
That's just one method, and others include using otoacoustic emissions (put sound in and record what sound comes back out), and behavioral responses (train the animal to respond to tones).
I can't speak to the comparative frequency ranges heard by different animals and I can't think of a quick place to look it up, sorry. Bats, dolphins and other echolocating animals have the most amazing auditory systems, for lots of reasons including an extreme frequency range. | [
"Several primates, especially small ones, can hear frequencies far into the ultrasonic range. Measured with a signal, the hearing range for the Senegal bushbaby is 92 Hz–65 kHz, and 67 Hz–58 kHz for the ring-tailed lemur. Of 19 primates tested, the Japanese macaque had the widest range, 28 Hz–34.5 kHz, compared wit... |
When did silent reading become common? | The passage you mention from Augustine (c. 398) is the most famous. A century later in Benedict of Nursia’s day reading aloud must have still been around. In his *Rule* (c. 520s) in ch. 48 he advises: “After the sixth hour, however, when [the monks] have risen from table, let them rest in their beds in complete silence; or if, perhaps, anyone desires to read for himself, let him so read that he does not disturb others.” Paul Sanger’s [*Space Between Words:
The Origins of Silent Reading*] (_URL_0_) would be a useful place for more details and a clearer chronology. Romans did not put spaces between written words. He argues that the practice of spacing words and developing clearer punctuation (beginning with 7th-century Irish scribes) aided the transition to silent reading.
| [
"The first Penguin edition of \"The Read-Aloud Handbook\" led to six additional U.S. editions, as well as British, Australian, Spanish, Chinese, Korean, and Japanese versions. Nearly two million copies of the \"Handbook\" have been sold worldwide, and it was the inspiration for PBS's \"Storytime\" series. It is als... |
why does the act of burning fuel at the buttom of a rocket make it move? what causes propulsion? | It’s like blowing up a balloon and letting it go, the air escaping the balloon makes it fly. Now imagine the balloon can keep creating air by burning fuel.
The liquid fuels combine to becomes gas, and more gas molecules are created, as well as being. Heated up by the reaction. The new hot gas must go somewhere, and there is only one outlet so the hot air is ejected from the bottom.
Since hot air is ejected from the bottom, by Newton’s third law, the rocket must also accelerate upwards. | [
"The effect of the combustion of propellant in the rocket engine is to increase the velocity of the resulting gases to very high speeds, hence producing a thrust. Initially, the gases of combustion are sent in every direction, but only those that produce a net thrust have any effect. The ideal direction of motion o... |
on old fashioned ships from the 1600s pirate times etc i’m guessing they had fires to keep warm how did they keep these safe and protect the wooden ship from burning? | In the age of sail, ship's cabins were poorly ventilated, and dozens (or even hundreds) of men would keep the cabin more than warm enough with their body heat alone when they were sleeping. When walking about the deck of the ship, warm clothing was about all that could be relied on.
Ships were extremely flammable, with not just wood and cloth but also tar for waterproofing the ship.
While there were ovens introduced later on, they were more for cooking and were not designed for heating the ship.
You can find more info here: [_URL_0_](_URL_0_) | [
"Warships of the age of sail were highly vulnerable to fire. Made of wood, with seams caulked with tar, ropes greased with fat, and stores of gunpowder, there was little that would not burn. Accidental fires destroyed many ships, so fire ships presented a terrifying threat. With the wind in exactly the right direct... |
What was the most powerful European country during the Middle Ages? Military, technology and economy. | Could you be a little more specific please?The "Middle Ages" covers a very long period of History, the answer will be very different comparing on when it is. | [
"In the course of the European Middle Ages, the European kingdoms underwent a general trend of centralisation of power, so that by the Late Middle Ages there were a number of large and powerful kingdoms in Europe, which would develop into the great powers of Europe in the Early Modern period.\n",
"Early modern Eu... |
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