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How do we know how large ancient/medieval empires were? How accurate are our maps of the areas of ancient empires today? | I cannot speak to the specific example of the Roman Empire under Trajan, but in the case of places/times like ancient Egypt and various powers in the ancient Near East there are references in texts from various time periods that specify locations of battles, places that were required to pay taxes, etc., which show that... | [
"Countries and areas with ancient histories, such as Ethiopia and Somalia, all have had eras of great empires. Various ancient empires extended and consolidated their power over large parts of the Horn region, such as the Axumite Empire (4th century BC–AD 10th century), the Zagwe dynasty (10th century - 1270), the ... |
After the Salem Witch Trials, is there any evidence of witches moving elsewhere to continue their religion? | To start off, I need to address the premise of your question. What you're asking assumes the presence of witches in Salem during the trials, but there were no witches in Salem. The 17th century New England definition of a witch referred to people who signed a covenant with Satan, thereby renouncing their covenant wit... | [
"An alternative explanation for the early modern witch trials, known as the Witch-cult hypothesis, was proposed by the German Professor Karl Ernst Jarcke in 1828. Jarcke's hypothesis claimed that the victims of the early modern witch trials were not innocents caught up in a moral panic, but members of a previously ... |
why is africa less affected by hurricanes and earthquakes than other continents? | North Atlantic winds are generally east-to-west, so storms move westward, building in intensity as they go. This is why most storms hit the Americas, not Africa.
South Atlantic winds are generally west-to-east, but conditions there are not favorable for forming hurricanes. The Atlantic Ocean is larger in the south, ... | [
"Climate change, and resulting increased temperatures, storms, droughts, and rising sea levels, will affect the incidence and distribution of infectious disease across the globe. This is true in Africa, where malaria continues to have dramatic effects on the population. As climate change continues, the specific are... |
The history and PTSD? | Hi! Not to limit further discussion, but you may find this [previous roundtable](_URL_0_) on the psychological diagnoses of past individuals useful.
| [
"PTSD became first evident due to those individuals who suffered extremely horrible experiences from war. Society noticed that those who took part in war, or had family members who took part in war, became distant from themselves and suffered terribly and found it very difficult to cope with the tragedies. Research... |
why does keeping a pillow between the legs near the crotch feel comforting(is it just me?)? | ...because it creates a gap between your legs and that gap helps your nuts. It relieves all that pressure on your nuts. | [
"A pillow can be used to provide support when one partner has back pain. A very common use of a sex pillow is to place it under the woman's buttocks or hips before assuming the missionary position; this pivots the pelvis and increases depth of penetration.\n",
"A sex pillow is a specially-designed and typically f... |
what exactly is shadow banking? | Shadow banking is the collective term for organizations that offer bank like services, but aren't regulated as banks.
Because banks take deposits from the public, they allow multiple people to have a claim on the same money. This is a very important role banks play in the modern economy, and because of this role, t... | [
"The shadow banking system is a term for the collection of non-bank financial intermediaries that provide services similar to traditional commercial banks but outside normal banking regulations. The phrase \"shadow banking\" contains the pejorative connotation of back alley loan sharks. Many in the financial servic... |
What is the cause of the sudden movements in the pattern on the surface of my coffee? (gif inside) | You're entirely correct in that this is caused by convection currents. The film is a lower density liquid, possibly microfoam caused by the brewing process. All of the swirls and other patterns are caused by the movement of liquid below it, due to temperature gradients. | [
"The coffee-ring pattern originates from the capillary flow induced by the differential evaporation rates across the drop: liquid evaporating from the edge is replenished by liquid from the interior. The resulting edgeward flow can carry nearly all the dispersed material to the edge. As a function of time, this pro... |
Was H.H. Holmes as prolific a serial killer as he claimed to be, or were his exploits largely exaggerated by himself and the media? | Holmes very definitely killed nowhere near as many people as recent writers, led by Herbert Asbury and Erik Larson, have suggested. Asbury, writing in 1940, was the first to suggest that Holmes's victims might have numbered "several hundred," the figure commonly encountered online today. Larson dismissed speculation th... | [
"Besides being a serial killer, Holmes was also a con artist and a bigamist, the subject of more than 50 lawsuits in Chicago alone. Many now-common stories of his crimes sprang from fictional accounts that later authors assumed to be factual. In a 2017 biography, Adam Selzer wrote that Holmes' story is \"effectivel... |
why can admitting to murdering someone yield an arrest, but admitting to doing illegal drugs doesn't? | Because generally "doing illegal drugs" is not a crime. It's possession or distribution that is the crime. | [
"Since 2011 prosecutors can elect to drop the charges if the amount of drugs seized is of a limited quantity (although no set limit is explicitly stated) and the drugs seized are believed to be for personal consumption only.\n",
"Another example is more extreme. Suppose the defendant is on trial for possession of... |
audio equipment has objective measurements of audio quality like frequency response & signal to noise ratio. why is this not used as part of the specifications for speakers etc? | They are... For good speakers. Not good speakers don't bother proving to you that they aren't very good.
If you buy a good speaker or microphone, it will likely come with a frequency response curve showing how accurately and at what power level it produces each frequency. | [
"The level of an audio signal is among the most basic of measurements, and yet widespread misunderstanding and disagreement about programme levels has become arguably the greatest single obstacle to high quality sound reproduction.\n",
"Many audio components are tested for performance using objective and quantifi... |
how in the hell does electromagnetism work? | Certain particles have charges. Charges can be one of two types, called positive and negative. There's no real reason positive charges are called positive or negative charges are called negative, that's just convention. A charge is surrounded by an electric field, and a moving or spinning charge is surrounded by a magn... | [
"Electromagnetism is the force that acts between electrically charged particles. This phenomenon includes the electrostatic force acting between charged particles at rest, and the combined effect of electric and magnetic forces acting between charged particles moving relative to each other.\n",
"BULLET::::- Elect... |
what is the benefit of being paid salary vs being paid hourly? | It really depends on the business & how they structure compensation.
In some places, "salary" just means you're going to be working unpaid overtime. In other places, you're actually given flexibility in your hours & get your full pay for a 30hr week (if all your work is complete).
In some fields, you know you're... | [
"Wages and salaries in kind consist of remuneration in the form of goods or services that are not necessary for work and can be used by employees in their own time, and at their own discretion, for the satisfaction of their own needs or wants or those of other members of their households.\n",
"The reason that emp... |
how come supercars (like the $2 million bugatti or others) aren't talked about for their safety features? do they not have to do the test crashes that "regular" cars have to do? | Safety isn't a selling point for a supercar. No one buys the safest supercar, they buy the fastest, flashiest pussy magnet they can afford. | [
"The car is infamous for its \"snap-oversteer\", this notoriety comes from numerous instances where individuals crash their SW20 either on or off the race track due to inexperience with a mid-ship platform, as MR layouts handle very differently in comparison to the common FF or even FR layouts. Even in its revised ... |
Black traps heat. Why do people around the equator/in hot areas have dark hair? | On a side note. Black clothing doesn't necessarily trap heat. In some cases it (can be cooler than white clothing because it can radiate body heat away faster)[_URL_0_]. | [
"Dark haired people, ranging from dark chestnut and deep brown to black, with either dark or light colored eyes, can also be seen among the Indo-European and non-Indo-European ethnic groups in Iran, the Caucasus, Central Asia, Afghanistan and India. Hair is naturally reflective, so black hair isn't completely dark ... |
why do monitors advertise screen ratios of 16:10 instead of 16:9? | Slightly more vertical resolution with 16x10, 1200 pixels instead of 1080. Yes you get black bars when watching 1080p video but more vertical space for everything else. | [
"16:9 (1.7:1 = 4:3) is an aspect ratio with a width of 16 units and height of 9. Since 2010 it has become the most common aspect ratio for televisions and computer monitors, and is also the international standard format of HDTV, Full HD, non-HD digital television and analog widescreen television. This has replaced ... |
how does a company mark the level of spice in a salsa? | Yeah, that just sounds like bad quality control.
Ideally, the recipe should call for a certain number of a certain kind of peppers. Assuming they use the same kind of pepper, they can get a pretty good idea of the [Scoville heat scale](_URL_0_) of the salsa (based on the heat of the peppers used).
Within the company... | [
"The company began with 24 spice basics and blends, the majority of which are still sold today. Now, the company manufactures 42 different spice blends and divides them among five flavor families: American Adventures, Pan Asian, Old World Classics, Latin Heat and Global Exotics. They also use these flavor families ... |
instead of building a space elevator from the earth upwards, why don't we build one that starts in space and reaches downwards? | Any space elevator would be build from the top down. After all, it's held up by the object it's anchored too in orbit, so you can't build it from the ground up.
That said, the idea has been proposed.
_URL_0_ | [
"A space elevator is a proposed type of planet-to-space transportation system. The main component would be a cable (also called a tether) anchored to the surface and extending into space. The design would permit vehicles to travel along the cable from a planetary surface, such as the Earth's, directly into space or... |
why are body fluids salty? | Our ancestor species lived in the ocean, which is salty, and grew to thrive in their only available habitat -- salt water.
As the next speciel started to climb out of the ocean and live on land, their bodies developed mechanisms to keep salt water inside, so that they could stay alive.
We still have those mechanisms. | [
"They have certain adaptations to live within their salty environments. For example, their cellular machinery is adapted to high salt concentrations by having charged amino acids on their surfaces, allowing the cell to keep its water molecules around these components. The osmotic pressure and these amino acids help... |
Did mammoths really only die 4000 years ago? | I believe you are referring to the dwarf mammoths of Wrangel Island in the Siberian Arctic. They are believed to have persisted until 7,000 to 4,000 ya. Terrestrial mammoths were pretty much gone by 9,500 ya. Mammoth populations that were trapped on islands due to rising sea levels often adapted by growing smaller whic... | [
"The mammoth is one of the most iconic extinct creatures. The episode features palaeontologist Sylvia Gonzalez and describes how disease and overhunting killed a whole family of Columbian mammoths in Toquila, Mexico. The family was buried in a mass grave and ranged from babies to adults. The end of the Ice Age was ... |
how does a small bullet that doesn't pass through the brain or heart kill a person? | Bullets inflict a lot of damage through a process called hydrostatic shock.
Water cannot be compressed, and most of your body is made up of water. So when a projectile like a bullet hits you and penetrates your skin, it exerts tremendous pressure on your cells. A 'wave" of pressure radiates from the projectile and th... | [
"BULLET::::- Brain death is the irreversible loss of measurable brain function, with loss of any integrated activity among distinct areas of the brain. Breathing and heart function must be maintained with assistive devices.\n",
"Bullets can indirectly disrupt the CNS by damaging the cardiovascular system so that ... |
why do reports use "mm" for million in the business world? | M is roman numeral for 1000 so MM is understood to be 1000 1000's. I assume they didn't use the M with line over it because of the limitations of typewriters. | [
"The \"billion\" in bya is the 10 \"billion\" of the short scale of the U.S., not the long-scale 10 \"billion\" of some European usage. Billion by this convention (10) is often called a \"thousand million\" in the UK and a \"milliard\" in some other countries. For this reason, there is potential for some confusion,... |
Where do the water go when the workers at the Fukushima nuclear plant spray water on them? | From what I've read, the half-life of the radioactive substances that would come from water (O^16 - > N^16 ) would be on the order of seconds.
[7.14 seconds, to be exact.](_URL_0_) | [
"BULLET::::- If water is present, it may boil, bursting out of its pipes. (For this reason, nuclear power plants are equipped with pressure-operated relief valves and backup supplies of cooling water.)\n",
"Forty-five tons of highly radioactive water leaked from the apparatus being used to decontaminate the water... |
why does wine is used regularly in formal occasions? | > Why can't you drink vodka in a diplomatic party
You kind of can.
I'll explain what I mean.
Wine is pretty difficult to cultivate. It's a high effort product. Takes years to get a plant to produce enough grape. Knowing which plant species works best in certain conditions. There is a trick and a lot of science in ... | [
"Wine is a beverage of significance and import, utilized in ceremonies, for example, celebrating Abraham's military victory and successful liberation of Lot, festive meals, and the libations comprising the sacrificial service.\n",
"Wine has had a long history of being served as an accompaniment to food. The early... |
can someone explain how and why mark rothko's work is considered art and how i can appreciate them? | Have you ever seen a Rothko in person? It makes a huge difference. First and foremost, they're BIG paintings. Second, he always wanted people to look at them up close. IIRC he said the ideal viewing distance as 18" (45cm). When you're that close to a huge painting, you literally can't see anything else. Your entire fie... | [
"Juamlon said that these spaces seem to be about his identity as well. Art cohabits a relation with spaces, and people as well, including teachers and friends who have allowed him to evolve, and share the life he has lived with them. He talks about his art as a matter of ideas that come from these everyday encounte... |
Do we have any info on the crew flying the plane that dropped the bomb on hiroshima? | I believe they knew. Here is a quote from the Pilot Colonel Tibbets:
**"When the bomb is dropped, Beser [the radio officer] will record your reactions. This record is for history, so watch your language."**
Source: Hiroshima by Stephen Hoare. Probably in plenty of other places too, but that's where I read it.
Here a... | [
"Flown by 393d commander, Major Charles W. Sweeney, it was assigned to the Hiroshima mission on 6 August 1945, as the blast measurement instrumentation aircraft. On the mission to bomb Nagasaki on 9 August 1945, it was to have been the aircraft carrying the bomb, but the mission schedule had been moved forward two ... |
why are there an abundance of fireworks stores around highways in rural areas? | Oftentimes firework sales are banned within city / suburban limits so people are restricted to selling them in rural areas. And people want to buy them, so putting them off of the highway makes them more available / quicker to get. | [
"However, gas lighting of streets has not disappeared completely from some cities, and the few municipalities that retained gas lighting now find that it provides a pleasing nostalgic effect. Gas lighting is also seeing a resurgence in the luxury home market for those in search of historical authenticity.\n",
"Ho... |
how did people protect against forgeries in the past? | By having trusted messengers, and by having everybody know everybody. If you're a nobleman, and you need to send a letter to the king, you think about whom to send to carry it, you first ask, *who among my family and inner circle, did I introduce to the king and his court, last time they visited this area?* I'll send h... | [
"Many forgeries still escape detection; Han van Meegeren, possibly the most famous forger of the 20th century, used historical canvasses for his Vermeer forgeries and created his own pigments to ensure that they were authentic. He confessed to creating the forgeries only after he was charged with treason, an offens... |
How do chimps take care of their nails? | Yes, they do bite their nails! It's the easiest tool at their disposal when a nail becomes too long or damaged and, not surprisingly, humans have the same habits when they lack the tools as well.
As far as use that keeps them short, I'm speculating that you're thinking of something like a dog running around that wear... | [
"Though not technically considered a histopathological technique, skin scraping – which involves taking a small sample of the epidermal cells of a dog, cat, or other household pet – is commonly used to detect the presence of mites.\n",
"Common chimpanzees (\"Pan troglodytes\") are sophisticated tool users with be... |
How are unknown chemicals identified? | First, this isn't my area of direct expertise, so this will be a somewhat generic answer as a chemist. Moreover, these answers are not specific to this scenario, but intended to be general.
The identification of a substance has multiple aspects, which may complicate the analysis while further refining or elucidating t... | [
"Historically, drugs were discovered through identifying the active ingredient from traditional remedies or by serendipitous discovery. Later chemical libraries of synthetic small molecules, natural products or extracts were screened in intact cells or whole organisms to identify substances that have a desirable th... |
what is the significance of the answer to isaac asimov's, the last question? | You mean, "Let there be Light," the most iconic phrase from the Book of Genesis?
The implication is that the Multivac, through answering the last question, essentially became the Creator of a new universe. | [
"Paul J. Nahin has described \"The Last Answer\" as \"one of the best stories [Asimov] ever wrote\", and posited that it \"illustrates [Asimov's] personal beliefs (and even hopes) about God and the hereafter\"; however, Nahin states that he is \"not convinced (...) that Asimov made his case logically\", arguing tha... |
While playing with magnets, I discovered that if you attach a ball bearing to one magnet and bring another closer, they will repel until they touch, and then snap together. Why is this? | The metal bearing act as a magnet. One could see it as if it has a lot of little magnets inside. Usually these magnets point to all directions, so it acts as if it is a neutral object. These little magnets are called [magnetic domains](_URL_0_).
If it is attached to the north-pole of one magnet, these little magnets... | [
"The armature may be a permanent magnet, in which case the coil or coils can exert both repulsive and attractive force on the armature. If there are two coils, they will be wound and connected so that their like poles face each other, so that when (for example) the poles facing the armature are both negative, one p... |
are satellites stationary with the earth spinning underneath them, or are they rotating in addition to the earths rotation. | Satellites are constantly falling around the earth. If their falling speed equals earths own surface rotation, that has some practical uses. | [
"To an observer on Earth, a satellite in a geostationary orbit appears motionless, in a fixed position in the sky. This is because it revolves around the Earth at Earth's own angular velocity (one revolution per sidereal day, in an equatorial orbit).\n",
"Orbital planes of satellites are perturbed by the non-sphe... |
why lung cancer, the deadliest of them all, receives so little funding compared to other types of cancer | First off, statistically speaking, Breast and Prostate cancers consist of the two highest rates of new cancer diagnosis, consisting of more than twice as many new cases per year as the next contender. One can argue that they are not 'the deadliest' forms of cancer because of the amount of money and research that has be... | [
"Cancer isn't just a disease that only affects wealthy countries. The World Health Organization reports that of the 7.9 million death from cancer every year, 72% (5.7 million) occur in low- and middle-income countries. This means that almost 11 people a minute are dying of cancer in some of the poorest nations on E... |
why does onion turn translucent when it's cooked? | Onions are made up of mostly colourless fluid. They appear white because of all The connective tissue in the onion. When you cook the onion the bonds holding the connective tissue break and they become more transparent.
It's similar to why polar bears look white.
Edit: I was wrong. Onions have air pockets which caus... | [
"This substance is present in garlic and onion. When onion or garlic is sliced, the substance evaporates and causes eyes to irritate. When garlic or onion is cooked, it also evaporates, ridding them of the spicy taste, and leaving a sweet taste in them .\n",
"Onion sauce is a culinary sauce that uses onion as its... |
why aren’t babies born immune to every illness their mother is immune to? | 1) the mother can provide passive immunity in the form of antibodies during breastfeeding. Those are temporary and not lasting.
2) the baby has its very own immune system that is separate from the mother's. The two do not interact or the mother's immune system would attack the developing baby and the baby would not s... | [
"Mothers who are immune to measles pass antibodies to their children while they are still in the womb, especially if the mother acquired immunity through infection rather than vaccination. Such antibodies will usually give newborn infants some immunity against measles, but these antibodies are gradually lost over t... |
how does a computer processor know how to compute different boolean operations? | > My question is how does the processor carry out these different boolean operations since it cannot physically rewire its circuits every time it needs to do a different operation.
It has different circuits for different operations. You said:
> It is my understanding that processors have millions of transistors.
... | [
"OoOE processors fill these \"slots\" in time with other instructions that \"are\" ready, then re-order the results at the end to make it appear that the instructions were processed as normal. The way the instructions are ordered in the original computer code is known as \"program order\", in the processor they are... |
how "economic hitmen" work | I'm going to just make up an example:
A private American firm, on behalf of the CIA/America goes down to Venezuela (or any poor/underdeveloped country with tons of non-renewable resources trapped in the ground). Its important the hit man is a civilian consultant so that should anyone blow the whistle on the guy, he c... | [
"A common example of this would be a person contracting a hit man, or a hired killer. Hit men commit the act of murder on a specific target or targets, and may receive payment in exchange for the murder or murders committed. This is what is known as contract killing. Hit men are most often associated with organized... |
Before the Luftwaffe accidentally attacked London, what was the general consciousness of the British public towards the war and Churchill's anti-nazi stance? | The majority of the British public were firmly behind the government and opposed to Hitler from the start of the war. Pacifism and disarmament movements were popular in the early 1930s but, with the rise of fascism, declined over the decade, and though there was still some support for appeasement and isolationism the M... | [
"Public opinion in Britain throughout the 1930s was frightened by the prospect of German terror bombing of British cities, as they had started to do in the First World War. The media emphasized the dangers, and the general consensus was that defense was impossible and, as Prime Minister Stanley Baldwin had said in ... |
what is the difference between sample rate and bit rate? | The sample rate is how many times per second you capture the signal. The bit depth is the number of bits of information in each sample. The bit rate is the sample rate multiplied by the bit depth. | [
"Average bitrate (ABR) refers to the average amount of data transferred per unit of time, usually measured per second, commonly for digital music or video. An MP3 file, for example, that has an average bit rate of 128 kbit/s transfers, on average, 128,000 bits every second. It can have higher bitrate and lower bitr... |
How did the Pilgrims sit on the ground, if not "Indian style"? | Before being termed "Indian style", it was (and still is in some places) known as sitting tailors fashion. This was called such because tailors most commonly sat upon their work table to keep the fabric clean and provide a good workspace. That particular method of sitting supports the back muscles and puts an even curv... | [
"The pilgrims arrive by all means of transportation. In fact many pilgrims walk all the way to Ayasos from Mytilene and other villages on the island, admiring the scenery along the way on the warm summer night in August. Most of the pilgrims walking to Ayasos make a stop at Karyni, in order to catch their breath an... |
Is it true that cellphone batteries gets worse if you charge them each night? | What practices are best depend on the type of battery. Nickel-based cells, such as NiMH and NiCd, need to be fully discharged occasionally, or else the battery loses capacity over time in a phenomenon known as "memory effect". Once a month (once every 30 charges) is sometimes recommended. This extends the life of the b... | [
"The E815 as well as the E816 variant used on the ill-fated Amp'd Mobile network both suffered from flawed internal battery charger software causing difficulties in charging the phone's battery. As a result, users had to resort to external battery chargers in order to continue to use the phone due to the internal c... |
why is it that children (and some adults) never hurt their own ear drums when they shriek but everyone elses hurts? | Do a silent scream. Make the motion but no noise and notice how your ears constrict. You're essentially closing them up when you scream. | [
"Ear pain due to an infection is the most common in children and can occur in babies. Adults may need further evaluation if they have hearing loss, dizziness or ringing in the ear. Additional red flags include diabetes, a weakened immune system, swelling seen on the outer ear, or swelling along the jaw.\n",
"High... |
How were the peoples of North Africa at the Islamic invasion of the 7th century organized? | North Africa at this time was part of the Eastern Roman Empire and it was a region known for its wealth - Egypt was the breadbasket of the empire, as it fed Constantinople and had a highly commercialised economy, and although the area around Tunisia was no longer as rich as it was during the high imperial period, it wa... | [
"The region of North Africa practiced many religions including various forms of pagan rituals, Judaism, and Christianity. The first Islamic forces encountered fierce opposition by the various city-states resulting from the departure of the Byzantines. The weakest of them in the southern and southwestern parts of th... |
New slave labour as economic input into Roman economy? | Hopkins (1978) and then Finley (1980 and following) had famously characterized the Roman world as a slave society and therefore a non-market economy. This view has now been firmly dismissed by the last thirty years of research on ancient economies.
There are now strong arguments, from many different scholars, that Ro... | [
"To varying degrees throughout Roman history, the existence of a pool of inexpensive labor in the form of slaves was an important factor in the economy. Slaves were acquired for the Roman workforce through a variety of means, including purchase from foreign merchants and the enslavement of foreign populations throu... |
Why wasn't the history of non-European cultures in North America taught in grade school in America during the 1980s and 1990s? | Sympathetically, the nature of history as a discipline was different. Historians and history teachers were interested in the precedents of modern society, and pre-Columbian North Americans aren't a precedent for modern society in North America: their populations and institutions were largely wiped out and replaced by ... | [
"The Native historical experience in the Americas is marked by forcible and sometimes willing attempts at assimilation into mainstream European American culture (Americanization). Beginning with missionaries and leading up to federally controlled schools, the aim was to educate American Indians so that they could g... |
During the first World War, did soldiers have tours of duty or were they there until they either died or the war ended? | Not tours so much as rotations. They would rotate through the trenches and then be back behind the lines where the could train gets some R & R and if lucky gets some leave too. Going home on leave was easier for the French and Germans but British soldiers could get home too. [Check out this great BBC piece about lif... | [
"During the First World War, many volunteers from the Defence Force travelled to Great Britain and joined the British Army, and many of them were killed in action. One of them mentioned by Sir Arthur Conan Doyle was Private Jacotine of the CLI, who was the last man left alive in his unit at the Battle of Lys, and w... |
i'm scared of credit cards. how do you use one wisely and efficiently? | Get one from the bank you have an account with.
Use it only to pay for things you can afford (like your gas) and only if you have the money in your bank account to pay it off.
Go pay it off now (once you use the credit card).
Only use it online on sites you trust.
This will help you build credit without spending a ... | [
"Frequently, smart cards, as a convenience, allow the user to run a negative balance. If this balance is greater than the cost of the card, the user may profit by simply discarding the card and purchasing another.\n",
"Individuals have better security and more convenience with using smart cards that perform multi... |
does earth have a perfect rotation? | Nope! It's called "apsidal precession." [Here](_URL_0_) is a gif that shows how it works, though this is wildly exaggerated for the sake of illustration. This gif shows a very large apsidal precession, ie the orbital pattern rotates drastically with each cycle.
To explain apsidal precession in a vacuum (ie ignoring th... | [
"Earth's rotation is not a simple rotation around an axis that would always remain parallel to itself. Earth's rotational axis itself rotates about a second axis, orthogonal to Earth's orbit, taking about 25,800 years to perform a complete rotation. This phenomenon is called the precession of the equinoxes. Because... |
What is the efficacy of valerian root in promoting the onset of sleep? | Not completely defined by now, but in any mechanism the lignanes in the root (Baldrianlignane in German) are guessed to have the most potential effects... it's a specific thread for our department of pharmacology and toxicology in Vienna, Austria!
The sleep-inducing effect is said to not come from the GABAerg activatio... | [
"A number of nonprescription medications have shown to be effective in promoting sleep. The amino acid tryptophan and its related compounds 5-HTP and melatonin, have common use, with the prescription medication ramelteon operating on the same biochemical pathway. The herb valerian can also be effective in gently in... |
If you were in a swimming pool on the Moon or Mars - Would you float higher, lower or the same? | The same. Buoyancy is dependent solely on the relative densities between the objects in question. Thus, you will float in water when you have displaced the same mass of water as you have. Masses and densities are not dependent upon gravity. | [
"When water enters a large body of water, such as a lake, a delta may form. Many craters and other depressions on Mars show deltas that resemble those on Earth. In addition, if a lake lies in a depression, channels entering it will all stop at the same altitude. Such an arrangement is visible around places on Mars ... |
Why wasn't there a big, fat "gunpowder empire" dominating early modern Europe à la the Ottoman, Mughal and Qing empires of Asia? | Because the Ottomans, Mughals, Qings, and Safavids had monopolies over the technical specialists and knowhow within their regions. In Europe, both France and the HRE had ownership or reign over regions where specialists and foundries popped up, so neither had an edge over the other. Additionally, the late middle ages s... | [
"The Gunpowder Empires mostly refer to the Ottoman, Safavid and Mughal empires. Each of these three empires were Islamic and had considerable military success using the newly developed firearms, especially cannon and small arms, in the course of their empires, but unlike Europe for example, the introduction of the ... |
Was there any sort of automotive/motorsports culture in the Soviet Union? What was it like? | I don't know much about specifically motorsports culture, but there have been a few recent studies on cars in the Soviet Union and Eastern Bloc. If you are mainly interested in racing and not automobile culture in general, there are a couple more specific links I've given at the bottom to images/videos. The rest of wha... | [
"Despite low prestige of those cars, they have shown an unbeaten accessibility and popularity among the Soviets, becoming the \"car for pensioners and intellectuals\". They were the cheapest Soviet-made cars. Quite a large number of them was produced in variants for disabled people, with modified steering.\n",
"B... |
tesseracts and spatial dimension? | The kind of extra spatial dimensions you're talking about are mostly the subject of philosophical pondering and "just for fun" thought experiments. Scientists seriously debating the existence of higher dimensions are usually talking about ittybitty extra dimensions that help solve string theory. Anyway...
Trying to vi... | [
"A tesseract is an example of a four-dimensional object. Whereas outside mathematics the use of the term \"dimension\" is as in: \"A tesseract \"has four dimensions\"\", mathematicians usually express this as: \"The tesseract \"has dimension 4\"\", or: \"The dimension of the tesseract \"is\" 4\".\n",
"A picture o... |
If I instantly cooled a litre of water to exactly 0° Celsius so that the temperature is completely uniform, would it freeze instantly or would it take some time? Why? | Heat/enthalpy of fusion seems to have been mentioned already, but to clarify how it works, if you took water and removed energy until it hit 0°C and then you stopped removing energy, you'd get totally liquid water with no ice in it, even if you had seeded it. When you start removing more energy, it stays at 0°C but ice... | [
"When liquid water is cooled, its temperature falls steadily until it drops just below the line of freezing point at 0 °C. The temperature then remains constant at the freezing point while the water crystallizes. Once the water is completely frozen, its temperature continues to fall.\n",
"David Auerbach describes... |
The accepted theory is that space is expanding. But what if everything (atoms etc.) is just becoming smaller? Is there a perceivable difference? | "Everything becoming smaller" is not really meaningful. We have to think about what gives things their size. The most basic building blocks of everything, elementary particles, are, according to everything we know, pointlike. They have no size.
So why does anything have a size? (Don't worry, there is a point to this.... | [
"Based on a huge amount of experimental observation and theoretical work, it is now believed that the reason for the observation is that \"space itself is expanding\", and that it expanded very rapidly within the first fraction of a second after the Big Bang. This kind of expansion is known as a \"\"metric\"\" expa... |
Is there any consensus on the Hun's ethnicity? | Hi there! While there aren't any flaired answers, you might still be interested in the following thread (if you haven't read it yet):
* [Who were the Huns? And where did they come from/ where did they go?](_URL_0_) | [
"Recent scholarship, particularly by Hyun Jin Kim and Etienne de la Vaissière, has revived the hypothesis that the Huns and the Xiongnu are one and the same. De la Vaissière argues that ancient Chinese and Indian sources used \"Xiongnu\" and \"Hun\" to translate each other, and that the various \"Iranian Huns\" wer... |
why do big vehicles like buses and freightliners have flat front, while smaller cars (and some freightliners too!) have longer and wedge-formed front? | Buses as a rule don't go all that fast, so aerodynamics isn't a big thing. Even on the highway, it more import to have more space than save gas, and a boxy shape does that. Also, in the city, having the driver that close to the front makes it easier for them to maneuver.
As for cargo trucks, in many countries there ... | [
"The full-width body gives a carbody cab unit poor rear visibility compared with a hood unit. For that reason, cab or carbody units are mostly used in situations where rear visibility is not important, such as power for through freight and passenger trains. Cab and carbody units are also more aerodynamic than hood ... |
Could you Destroy a Black Hole by feeding it a whole bunch of Anti-Matter | No. Adding antimatter or matter to a black hole increases the black hole's mass. In fact, there is no difference between a black hole assembled from a bunch of matter or a bunch of antimatter.
The Hawking calculation of black hole radiation does NOT suggest that antimatter going into a black hole decreases the size ... | [
"Steinhardt, Spergel and Jason Pollack have proposed that a small fraction of dark matter could have ultra-strong self-interactions, which would cause the particles to coalesce rapidly and collapse into seeds for early supermassive black holes.\n",
"BULLET::::- Red Matter. A material capable of creating black hol... |
Did the theory that light propagation was instant ever co-exist in history with an accurate understanding of the dimensions of space? If so, what sort of problems did this cause? | It's possible that somebody out there in the depths of history managed to *get* the geometry of spacetime without understanding how it's related to the propagation of light, but it's hard to imagine how they'd suss out one while remaining unaware of the other. As far as actual written records go, the understanding that... | [
"In 1962 J. G. Fox pointed out that all previous experimental tests of the constancy of the speed of light were conducted using light which had passed through stationary material: glass, air, or the incomplete vacuum of deep space. As a result, all were thus subject to the effects of the extinction theorem. This im... |
If an infinite amount of energy is required for a particle to reach the speed of light, and a photon is a elementary particle, how can a Photon reach the speed of light? | Things with mass cannot go faster than the speed of light.
Massless things must *always* go at the speed of light. | [
"While the particle's energy was higher than anything achieved in terrestrial accelerators, it was still about 40 million times lower than the Planck energy. Particles of such energy would be required in order to explore the Planck scale. A proton with that much energy would travel times closer to the speed of ligh... |
why is everyone so up in arms about "drone warfare", whats the difference between a remote plane and a real one? | Perception.
There's a perception that it's unfair play. There's no danger to the person operating the drone. Also, I think many people inaccurately believe that a pilot in a plane is less likely to hurt civilians than a fellow in a basement in Missouri looking at a computer screen.
It's like hunting with a machine ... | [
"Drones are used by the military in situations where manned flight is considered too risky or difficult. The United States Air Force has drones that range from small intelligence drones to surveillance drones and large spy planes. The drones are unmanned, but they have a pilot. Trained crew steer the craft through ... |
Why and when did Existentialism arise? | Kierkegaard's reply to Hegel, particularly in "Concluding Unscientific Postscript." | [
"Anaximander, who believed that all things arose from the elemental nature of the universe, the \"apeiron\" (ἄπειρον) or the \"unbounded\" or \"infinite,\" was likely the first western thinker to propose that life developed spontaneously from nonliving matter. The primal chaos of the \"apeiron,\" eternally in motio... |
Why did communist societies of the 20th century restrict freedom of expression/dissent to the extent that they did? Is it at all related to Marxist theory? | Marx actually spoke very little about how society and government would function in a Communist society. Most of the philosophy that contributed to the running of socialist states (recall that Communism was a state to be reached after a certain level of development) came much after Marx.
In fact, Marx specifically sai... | [
"The rise of totalitarian regimes in Germany, Russia, and other countries who rejected freedom of speech and association had a large impact on the civil liberties movement in the US; anti-Communist sentiment rose and civil liberties were curtailed.\n",
"For the \"[New Yorker Volkszeitung]\" veteran, the struggle ... |
Wikipedia says that "Research indicates that Muslims in the United States are generally more assimilated and prosperous than their counterparts in Europe." Why is this? | Pretty sure this violates the recent history rules but I'd love to hear an explanation using information dating maybe to colonialism? | [
"Nevertheless, these incentives off or improving territorial security in Europe remain subject to countervailing attitudes and political forces. Germany, the United Kingdom, and France all have large Muslim populations. And whereas the roughly1 5million Muslims living in the EU'S 15 current member states constitute... |
if a small child was to go into a coma for an extended period of time, how would they age? details inside. | Yes, they would grow like a normal person. No, they would not learn any new knowledge during that time. | [
"Comas can last from several days to several weeks. In more severe cases a coma may last for over five weeks, while some have lasted as long as several years. After this time, some patients gradually come out of the coma, some progress to a vegetative state, and others die. Some patients who have entered a vegetati... |
Did the Romans have a concept of technological progress? Would they have been aware of the fact they they had better weapons than Trojans would have had? | Yes, the Romans certainly had a concept of technological progress, but one that is hardly comparable to ours. Here are some most obvious differences to consider; 1) the Romans did not always account technological advancement as much to the efforts of a line of human inventors, but saw it as a divine process which was i... | [
"That said, the Romans also developed a huge array of new technologies and innovations. Many came from common themes but were vastly superior to what had come before, whilst others were totally new inventions developed by and for the needs of Empire and the Roman way of life.\n",
"The technology was developed qui... |
If by getting faster time slows down, is there a reference point where time goes faster than everything else ? | Sure. Time goes the fastest if you're moving in a straight line at a constant speed (and when you're in zero gravity, if you're using General Relativity).
Beyond that, it gets a bit muddly. If you're on a spaceship moving in a straight line at a constant speed away from the Earth (which we'll assume is stationary), pe... | [
"Common sense would dictate that, if the passage of time has slowed for a moving object, said object would observe the external world's time to be correspondingly sped up. Counterintuitively, special relativity predicts the opposite. When two observers are in motion relative to each other, each will measure the oth... |
After losing the War of the Third Coalition, why did the Holy Roman Empire dissolve? | I do apologize if an answer to this question has taken significant time, and though I had answered this to a certain extent [here](_URL_0_), I am always happy to elaborate further.
Essentially, if we follow Peter Wilson's opinion in his book *Heart of Europe: A History of the Holy Roman Empire*, ostensibly, imperial l... | [
"In 1805, the French victory over an Austrian-Russian army at the Battle of Austerlitz ended the War of the Third Coalition. As a result of the Treaty of Pressburg, the Holy Roman Empire was dissolved.\n",
"The War of the Third Coalition lasted from about 1803 to 1806. Following defeat at the Battle of by the Fre... |
why is it that when we were younger, we could eat copious amounts of junk food, but when we're older it makes us sick? | When you were younger you would still get sick but i presume your parents limited you in some form.
If you mean why does it affect us harder at a greater age, our bodies slow down, it takes a bit longer for everything to be processed, in turn it makes it easier to get "too much".
| [
"In a study published in the \"European Journal of Clinical Nutrition\", the frequency of consumption of 57 foods/drinks of 4000 children at the age of four and a half were collected by maternal report. At age seven, the 4000 children were given the Strengths and Difficulties Questionnaire (SDQ), with five scales: ... |
when many people read, we see the story played out like a movie in our minds instead of the words on the page... what is the neurological explanation of this? how does it happen? | Our mind's eye is the connection between our conscious and subconscious thoughts. When we are told something we try to envision it to better understand it. When reading a well written story involving things that don't exist or have never seen before our internal process of understanding is working harder to create the ... | [
"BULLET::::- Merton making a movie reference, then instead of talking about the movie itself, he would talk about either how the film was received or what he felt when he watched it. Tommy usually hits him and says \"In the \"movie\"!\" e.g. \"This is like \"The Purple Rose of Cairo\", Woody Allen's Oscar-nominated... |
i understand the concept of how ray-tracing works, but what was changed to make it work in real-time on graphics cards? | New algorithms simplify the computations required. Also, building GPU chips for ray tracing means the hardware is better suited for the specific tasks that ray tracing demands.
We've heard for years that real-time ray tracing was decades away from being possible (or perhaps impossible), but that was assuming every sin... | [
"In computer graphics, ray tracing is a rendering technique for generating an image by tracing the path of light as pixels in an image plane and simulating the effects of its encounters with virtual objects. The technique is capable of producing a very high degree of visual realism, usually higher than that of typi... |
why do we have peppermint candy and ice cream but not spearmint? | I see plenty of spearmint candy...not the ice cream though...but they make cheese flavored ice cream, so Im sure someone makes a spearmint flavor...maybe Italian gelato comes in that variety? | [
"Russian candy or Russian chocolate (; \"iriski-tyanuchki\") is a very sweet toffee-like dessert made by carefully heating equal amounts of milk or cream and sugar. It is a traditional dessert sauce in Nordic countries. Karl Fazer brought the first \"Russian candy\" recipe to Finland from St. Petersburg.\n",
"In ... |
What War Crimes did Romania, Romanian Armed Forces and the Iron Guard commit during WW2? | For example Soviet city of Odessa was occupied by Romanian army. Concentration camps and ghettos (and also extermination) were under Romanian jurisdiction (new Romanian Transnistria Governorate). Odessa had up to 90.000 Jews prior to occupation (October 1941). By February 1942 only 20.000 were still alive. They were d... | [
"By the end of World War II the number of Romanian prisoners of war in the Soviet Union was significant, about 140,000 of them having been taken prisoner even after August 23, 1944, the date when Romania switched its alliance from the Axis Powers to the Allies.\n",
"The Iron Guard movement of interwar Romania has... |
why do certain website stores require you to register before being allowed look at their items? how do they think this will attract more customers? | There's a couple reasons.
One of the one's we had at our old website storefront was this though.
If you have a "published" website, then you have to adhere to the MSRP/MAPP pricing. Manufacturers Suggested Retail Price/Minimum Advertised Pricing Policy.
Let's say you have a pair of pants with a $50 price tag. The ... | [
"Wendy Moe (2003) argues that in the offline environment, consumers who are shopping in stores can be easily classified by experienced sales employees only by watching their shopping behaviours. These sales will approach them initiatively because they knew they look like the kind of consumers who are really seeking... |
Spirits:A question about the aging of whisky. | The [sheer number of compounds](_URL_0_) make it not feasible to do. Even if we have identified _all_ the compounds, it takes tremendous effort and energy to produce those via synthetic methods. Definitely not worth it, considering we have a _very_ well established method and an organism that does most of the work for ... | [
"While aging in wooden casks, especially American oak and French oak casks, whisky undergoes six processes that contribute to its final flavor: extraction, evaporation, oxidation, concentration, filtration, and colouration. Extraction in particular results in whisky acquiring a number of compounds, including aldehy... |
why am i supposed to use a different plate every time i go up to a buffet? | Its a food hygene and health issue. Not to say buffets are paragons of cleanliness, but the idea is that if you've been sneezing, drooling and spitting all over your plate, they don't want you exposing that crap back to the buffet. Also minimizes chances that some numbskull will just slide his half eaten chicken fried... | [
"A buffet (, , from French word for \"sideboard\") is a system of serving meals in which food is placed in a public area where the diners serve themselves. A form of \"service à la française\", buffets are offered at various places including hotels, restaurants, and many social events. Buffet restaurants normally o... |
Why did Mayotte vote to stay in France while the rest of the Comoros islands voted for independence? | That is a very good question. I have always been interested in the topic and wrote a paper on it, so I'll try to address it.
In 1958 with the new Constitution and then in 1961 with a law organizing the internal autonomy of the Comoros (according to some this is the first time the French government considered the Como... | [
"Mayotte was the only island in the archipelago that voted in referenda in 1974 and 1976 to retain its link with France and forgo independence (with 63.8% and 99.4% of votes respectively). The United Nations' constant policy regarding decolonisation has been that independence must be effected in the framework of th... |
why do movies/tv shows set in present time often use outdated technology/software? | Like...? I can't think of an example? | [
"In the age of digital television, high definition television and DVD, film preservation and restoration has taken on commercial as well as historical importance, since audiences demand the highest possible picture quality from digital formats. Meanwhile, the dominance of home video and ever-present need for televi... |
why do molocules have such long and difficult names? | Because they're descriptive!
Carbon dioxide tells you there are two oxygens and one carbon
Ethylmethylamine tells you you have one ethyl group, one methyl group, and an amine in the middle
For many commonly used chemicals there are common names. Sodium bicarbonate is commonly known as baking soda. Potassium Chlori... | [
"Many trivial names continue to be used because their sanctioned equivalents are considered too cumbersome for everyday use. For example, \"tartaric acid\", a compound found in wine, has a systematic name of 2,3-dihydroxybutanedioic acid. The pigment β-Carotene has an IUPAC name of 1,3,3-trimethyl-2-[(1E,3E,5E,7E,9... |
[CHEMISTRY] Why is making high quality meth so difficult? | Producing chemicals is more complex than just a simple chemical reaction equation and mixing two things together. You often need catalyst, energy inputs, dopes, and timing.
I used to do research in mechanochemical alloys and have a fair amount of lab experience with producing chemicals. Applying too much energy to a m... | [
"Methamphetamine more commonly known as crystal meth, is a highly addictive drug. A fair amount of research indicates that the use of methamphetamine is associated with neurocognitive impairment, more recently there has been a focus on whether these difficulties extend to memory for future intentions. Rendell et al... |
district of columbia and the 50 states | The District of Columbia was a compromise worked out by the framers of the Constitution. The location of the national capitol was a big deal in the eighteenth century. During a process where not too many compromises of principle were possible, the location of the capitol was a bargaining chip.
If the capitol had bee... | [
"The District of Columbia was created in 1801 as the federal district of the United States, with territory previously held by the states of Maryland and Virginia ceded to the federal government of the United States for the purpose of creating its federal district, which would encompass the new national capital of t... |
people crap in the restroom and others find it disgusting? | Because society has taught us that we should be quiet, and that pooping is a disgusting thing.
We lose sight of what is natural, sometimes.
Although, the other day, a guy in the stall next to me was so loud and pooping so hard, it really put me off my sandwich. | [
"As they make their way, they leave behind a trail of crude jokes and plentiful puns. They make fun of a \"daimyō\" procession, cheat shopkeepers out of money, and get cheated in turn. At one inn, they make fools of themselves because they do not know how to use the bathtub; they burn themselves on the bottom, rath... |
Before Greek independence, what was the geographical extent of "Greece", as a region? | The Greek name for Greece is Hellas, which is composite from Helios and Laas, which would translate as 'Sunland'.
At the ancient times, Greeks would call 'Sunland' the region around mountain Parnassus, which was considered to be the mountain of god Apollo, god of the Sun, and lies in about the middle of modern Greece.... | [
"In March 1821, the Greek War of Independence from the Ottoman Empire began. The Greeks formally declared their independence in January 1822, and after the Battle of Navarino in 1827, the establishment of a Greek state was recognized in the London Protocol of 1828. The first borders of the Greek state consisted of ... |
what does sport mode do to my car (2015 jeep grand cherokee, if you're familiar)? i just don't notice much difference... | It changes the way your transmission and traction control are set up. Sport mode will let your engine rev higher in each gear to get more power down to the road instead of being set up for fuel efficiency and your traction control will most likely turn off. In some fancy cars the throttle (gas pedal) and suspension wil... | [
"The transmission consists of three modes, \"Automatic (D)\", \"Manual (M)\" and \"Sport (S)\". The Automatic mode focuses on driving comfort while the Sport mode reduces shift time and throttle response. When combined with the \"Sport\" or \"Sport +\" driving modes of the Drive performance system, the gearshifts a... |
Are there any writings that we used to consider myths/legends that have been recently corroborated by archaeology and have a historical basis? What about any myths/legends passed down orally? | Here's one of my favorite archaeologically documented oral legends.
The site of [Chavin de Huantar](_URL_0_) was the center of a first millenium BC religious cult that spread its cultural influence across the entire Andes. Folks have been excavating there for decades now. The current team was excavating some areas jus... | [
"It can also be regarded as ancient history, \"part of a broader spectrum of originally anonymous, history-like ancient Near Eastern narratives.\" It is frequently called myth in scholarly writings, but there is no agreement on how \"myth\" is to be defined, and so while Brevard Childs famously suggested that the a... |
how does our nervous system work in regards to how we feel through the use of neurotransmitters and medication? | Please note that a lot of our information about neurotransmitters (and how the brain works in general) is correlative, not causative.
We know certain neurotransmitters correspond with certain conditions. We know that the lack of them, or an excess of them can be correlated with certain disorders.
For example, dopam... | [
"The major neurotransmitter systems are the noradrenaline (norepinephrine) system, the dopamine system, the serotonin system, and the cholinergic system. Drugs targeting the neurotransmitter of such systems affects the whole system, and explains the mode of action of many drugs.\n",
"The enteric nervous system ma... |
what is today xkcd (_url_0_) comic supposed to be? | There is a neat little site useful for the more obscure posts:
_URL_0_
| [
"Unusually for a comic set in an established publisher-owned universe, \"Xerø\" was half creator-owned: though all the characters featured in the book belong to DC Comics, Priest co-owns copyright to the stories and art. The series had limited interaction with the rest of the DCU; Doctor Polaris made a guest appear... |
Will cooling a piece of plastic increase its rigidity? | Yes it does. If you have access to a suitable piece of plastic, why don't you stick it in the freezer for a while and see for yourself? You will have to be fast though, plastics tend to warm up quickly (low heat capacity) so if you wait too long you'll feel it return to room-temperature elasticity quickly.
The most ex... | [
"The density of microcellular plastics has the greatest influence on the behavior and performance. The material tensile strength linearly decreases with the material density as more gas is dissolved into the part. Melting temperature and viscosity also decrease as well.\n",
"Most carbon-based materials deteriorat... |
How do other apes keep their nails short? | I always see my dogs chew them, and I've seen videos of primates biting them, among other animals with similar claws and nails. As I've witnessed caring for many different animals and observing others, active animals will use their claws and they'll break here and there from regular use. It's not like nail biting is so... | [
"A nail is a horn-like keratinous envelope covering the tips of the fingers and toes in most primates. Nails evolved from claws found in other animals. Fingernails and toenails are made of a tough protective protein called alpha-keratin which is found in the hooves, hair, claws and horns of vertebrates.\n",
"When... |
what are the differences and similarities between personality (i.e. personality traits) and character (i.e. virtues and possibly vices)? | Semantics and whether you care about morals, primarily.
A quick Google for definitions gives: personality, the combination of characteristics or qualities that form an individual's distinctive character; character, the mental and moral qualities distinctive to an individual. Two different ways of saying (roughly) the ... | [
"Personality type refers to the psychological classification of different types of individuals. Personality types are sometimes distinguished from personality traits, with the latter embodying a smaller grouping of behavioral tendencies. Types are sometimes said to involve \"qualitative\" differences between people... |
why does the government pay farmers to limit how much they produce? | It could be for a number of reasons.
One being top soil depletion. If farmers are working their land to the max all the time because that's how they make their money then the soil can become "exhausted" and another dust bowl or famine would happen.
It's also good for smaller farms. By limiting production, it allows ... | [
"The average U.S. farmer receives $16,000 in annual subsidies. Two-thirds of farmers receive no direct payments. Of those that do, the average amount amongst the lowest paid eighty percent was $7000 from 1995-2003. Subsidies are a mix of tax reductions, direct cash payments and below-market prices on water and othe... |
why do dogs and cats lift their paws really high when they have socks or booties on? | They feel as though they can lift their feet out of them. It's the same logic as when you put something on their head and they walk backwards trying to back out of it. It's the simplest most direct way to escape something so I'm assuming that's what they're trying to do. | [
"Dogs are able to push while standing on a skateboard, or they can run towards the board and leap on. Most skateboarding dogs have difficulty carving because they cannot easily shift their weight on the board. Dogs cannot grind. Dogs are agile on the board and are able to turn around or perform other walking moves ... |
How do power plants maintain a 60 Hz frequency? | [This site](_URL_0_) shows (realtime!) how the various US grids change frequency as they source or sink power from each other. | [
"Transformers do not change the frequency of electricity; in many regions with 100–120 V, electricity is supplied at 60 Hz, and 210–240 V regions tend to use 50 Hz. This may affect operation of devices which depend on mains frequency (some audio turntables and mains-only electric clocks, etc., although modern equip... |
Can lasers be focused to reach an arbitrarily large intensity? (Optics) | First of all, due to conservation of energy, you can not heat stuff up more than the laser output allows. Second, you can increase the energy densitiy by focusing the beam. This will increase the temperature in this very tiny spot. But you can not make the focus size smaller than about the wavelength of the laser frequ... | [
"Some lasers do not use an optical cavity, but instead rely on very high optical gain to produce significant amplified spontaneous emission (ASE) without needing feedback of the light back into the gain medium. Such lasers are said to be superluminescent, and emit light with low coherence but high bandwidth. Since ... |
why are vintage guitars considered to sound better than modern ones? | As the wood ages, the tone generated by the wood changes (usually in a desirable manner). Since the wood in older guitars has aged, the tone from that wood "sounds better". Also, when you are dealing with analog circuitry, there are quirky tones and characteristics generated by the components in those older guitars. Si... | [
"A vintage guitar is an older guitar usually sought after and maintained by avid collectors or musicians. The term may indicate either that an instrument is merely old, or that is sought after for its tonal quality, cosmetic appearance, or historical significance.\n",
"Vintage musical equipment is older music gea... |
What would happen if all the great white sharks died off? | They don't just eat fish. They eat other predators (including other sharks), keeping their numbers at reasonable levels. Removing them would first allow fish to flourish more, which would then lead to a boom in a ery high breed rate and inefficient predator, wihich would ultimately put a higher strain on fish populatio... | [
"When a great white shark eats the potential catch of a sport fisherman, the man and his daughter violently retaliates by sadistically torturing and killing the shark, whose corpse then sinks to the bottom of an underwater cave and is subsequently resurrected as a ghost shark due to the cave's mysterious paranormal... |
Why was the province of Carolina split into North and South Carolina? How were the new boundaries determined? | Yesterday I asked [a question](_URL_0_) directly related to yours. Hopefully someone with knowledge of this subject will show up! | [
"The northern and southern sections of the Carolina colony operated more or less independently until 1691, when Philip Ludwell was appointed governor of the entire province. From that time until 1708, the northern and southern settlements remained under one government. However, during this period, the two halves of... |
difference between cars in nascar | Downforce settings, camber settings, fuel levels, etc. The cars are supposed to be carbon copies of each-other prior to the engineers "tweaking" several settings, giving the driver a different feel on the track. | [
"NASCAR teams compete in all three national NASCAR series: the Monster Energy NASCAR Cup Series, Xfinity Series, and Camping World Truck Series, as well as in all the regional touring series. A team is limited to four cars in each of the NASCAR series. The team often shares a single manufacturer for all of the team... |
where do all the chromosomes “go” during mitosis? | All the chromosomes split like the 1 or 2 you see in the pictures. It's just so much easier to see what's going on and to fit a diagram on the page without drawing every single chromosome. For example, [here's what mitosis looks like in onion cells.](_URL_0_) The cells look really crowded and onions only have 8 chro... | [
"When mitosis begins, the chromosomes condense and become visible. In some eukaryotes, for example animals, the nuclear envelope, which segregates the DNA from the cytoplasm, disintegrates into small vesicles. The nucleolus, which makes ribosomes in the cell, also disappears. Microtubules project from opposite ends... |
why flies don't get sick from eating rotting flesh and feces? | I'm fairly certain that flies don't directly eat flesh and feces. They spew us some kind of acid/enzyme that breaks the materials down into something they can digest safely. | [
"Flesh flies can carry leprosy bacilli and can transmit intestinal pseudomyiasis to people who eat their larvae. Flesh flies, particularly \"Wohlfahrtia magnifica\", can also cause myiasis in animals, mostly to sheep, and can give them blood poisoning, or asymptomatic leprosy infections.\n",
"While flies and larv... |
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