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why are comic books published date set in a future date? | The date on the cover isn't actually when the comics come out. Instead, the date signifies when newsstand owners / store clerks should remove them from the shelves!
It's sort of an outdated practice, as most comic stores just put them in a box somewhere, but there you go. | [
"The general practice of most mainstream comic book companies since the creation of the comic book in the 1930s was to date individual issues by putting the name of a month (and much later the year as well) on the cover which was generally two months after the release date. For example, a 1951 issue of \"Superman\"... |
[technology]how does mobile data consumption change when watching a video vs downloading it? | No. There's no difference in the data-rate between streaming and downloading a video. When downloading, all you're doing is taking the exact same video and storing it locally. The same information has to come from the video's host either way. | [
"Mobile consumption of video content in particular makes cloud delivery of video attractive, because remote processing and storage can compensate for the limitations of mobile devices. As much as 75% of the world’s mobile data traffic is expected to be video by 2020.\n",
"The global trend of viewing videos throug... |
Why does thermite release it's energy as incredible heat rather than exploding? | Thermite doesn't produce any gas. Aluminium reacts with Iron oxide. The result is Iron and Aluminium oxide, both solids (or, liquids because of the heat). So the volume stays (mostly) the same, and no explosion happens. | [
"Thermite () is a pyrotechnic composition of metal powder, which serves as fuel, and metal oxide. When ignited by heat, thermite undergoes an exothermic reduction-oxidation (redox) reaction. Most varieties are not explosive, but can create brief bursts of heat and high temperature in a small area. Its form of actio... |
how can the brain make you sleepwalk, but not turn you on your side if you are choking on your vomit? | People who are vomiting in their sleep are either very sick, or (much more likely) intoxicated. Their brain is therefore in a state of reduced effectiveness. | [
"Sleepwalking and other forms of disorders of arousal occur from deep non-REM slow wave sleep (SWS). There are parasomnias that occur from rapid eye movement sleep. It is caused by an inappropriate physiological event where the brain tries to exit SWS and go straight to wake. In normal sleep, the brain transitions ... |
What percentage of men who went to fight in medieval wars could expect to come home? | I do not know about the medieval period but in the Early Iron Age (Pre-Alexander Hellenic Greece), infantry armies rarely inflicted more than 10% casualties even in a decisive defeat. That being said, the majority of casualties in war have always been from disease and accidents rather than from actuall contact with the enemy. | [
"By 1618 when war broke out, advances in weapons technology and in military organisation had made warfare significantly more lethal, even, than it had been in the Medieval period, not merely for soldiers but also for any civilian populations that found themselves in the wrong place. Located on a principal communica... |
So water causes the soluble coating on tide pods to disintegrate 10 seconds or so after you place it in the washer. However, inside the pod there is a concentrated detergent that also has water in it. So why doesn’t the liquid inside the pod also cause it to disintegrate? | After[ searching through the patents](_URL_0_) of some detergent delivery pods, I couldn't find anything about a coating or different polymer being used on the insides of the pods. I believe the answer is that for the polymer to dissolve it needs to be fairly well hydrated. The insides of the pods are actually relatively "dry", so to speak, due to the very high concentrations of electrolyte. Only placing the pods in water allows the external polymer film to become hydrated enough for substantial hydrolysis to occur. | [
"When particles to be removed do not settle out of solution easily, dissolved air flotation (DAF) is often used. After coagulation and flocculation processes, water flows to DAF tanks where air diffusers on the tank bottom create fine bubbles that attach to floc resulting in a floating mass of concentrated floc. Th... |
How does mRNA "know" wether to travel to a bound ribosome vs. a free ribosome? | In general molecules moving about in a cell don't have any idea where they're going. There is no conscious action or directive that tells them what to look for and what to bind to. What actually happens is that they fly around randomly, perhaps being pulled this way or that way by a pressure, concentration, or voltage gradient, but for the most part they bump into thousands of things along the way. What makes mRNA choose the correct ribosome is that this is the only kind of ribosome that mRNA will fit into. So in its thousands of interactions with other molecules, just by chance when it interacts with the right one, it will bind and the interactions will stop. If you take a snapshot at the beginning and at the end of this process, it will appear as the mRNA knew exactly where to go, but it really just tired its key in all the different locks until it found one that worked. | [
"During translation, ribosomes convert a sequence of mRNA (messenger RNA) to an amino acid sequence. Each 3-base-pair-long segment of mRNA is a codon which corresponds to one amino acid or stop signal. Amino acids can have multiple codons that correspond to them. Ribosomes do not directly attach amino acids to mRNA... |
By the time the Berlin Wall fell, had the more than 40 years of separation led to notable differences between the Standard German spoken on either side of the wall? | Expanded from an [earlier answer of mine](_URL_2_)
German division did not create a wholesale division of the language. Although there certainly was a political divide between the two Germanies, the cultural divide was somewhat less salient. Both the FRG and the GDR tried to lay claim to Germany's cultural heritage and there were similar pedagogy when it came to instilling proper German. The GDR public could receive Western broadcasts outside of a few areas and one of the few bright spots in the planned economy was its production of television sets. The era of *Ostpolitik* in the 1970s also greatly facilitated West-East contact as the GDR opened up its borders to FRG travelers (and their hard currencies). East-West travel was much rarer and more supervised in this period, but not unheard of either. So despite the political division of the country, there were some areas of common ground between West and East Germans. Language was one such area.
There really was not that much of an imposed change on the German language in the GDR. Most of the differences between the two Germanies were lexical. Some of this was partly the fault of division. For example, in the GDR *Kaufhalle*/*Konsum* were used for grocery stores while in the FRG *Supermarkt* became more common. *Brigadier* remained a reference to the military rank in the FRG, while in the GDR it became a reference to the work brigades that were all too typical of the planned economy's reliance upon shock labor to fulfill production quotas. The GDR's educational and cultural authorities also looked askance at English. The state put relatively little effort into teaching English and state media often declined to countenance the penetration of the language by such a *Feind*. The result of this was the GDR lexicon had far fewer English loan words than their FRG counterparts. Other relatively unique GDR words were a byproduct of the state ownership of various goods and services and their state-given names became part of the everyday vocabulary. The widespread culture of *Eingaben* (petitioning the state) also ensured that some SED euphemisms and jargon penetrated into daily use.
But not all of the lexical differences were political in nature. The GDR's restriction of movement and its housing crisis also helped to entrench linguistic dialects as GDR as people could not move around easily. The different nature of GDR feminism and debates over the women question meant there was less of an attempt to make German more gender-inclusive in the GDR than in the FRG. Tellingly, neither *Sexist* nor *Sexismus* made much of a penetration into official language outside of occasional attacks on the moral degeneration of the West. German wikipedia has a [list of words](_URL_3_) used in the GDR lexicon.
One of the exceptions to this trend was the use of the du-form. The ruling SED party did encourage the use of the informal *du* (you) over the more formal *Sie* (you). In traditional German language convention, the informal tends to be reserved for personal settings while the formal is often used in workplace settings or ones other social situations where one party is superior, such as pupil/student or employee/boss (note this is a generalization and can be observed as much in breach in some areas- DW has a good explanation of the [du/Sie dilemma](_URL_1_) ). The cultural authorities in the GDR portrayed this formal/informal division as a relic of Germany's inequitable society and did not represent the new worker's state created by the SED. In this, they were building on older traditions of German labor activism and extending the imagined solidarity of the shopfloor to the whole nation. In the workshops and in SED functions, the state encouraged the use of the informal to stress that all the citizens of the state were social equals. GDR state media often emphasized the term *Genosse* (comrade) and it evolved into a quasi-title for SED officials in print (such as "Rede des Genossen Walter Ulbricht," and so on). The SED privileged *Genossen* over the term *Kameraden* because the latter was more frequently associated with comradeship in an organizational context, often martial, exemplified by such the songs like ["Ich hatt' einen Kameraden](_URL_0_) or ["Alte Kameraden"](_URL_4_).
Ironically, this social leveling by language had something of an opposite effect upon the GDR public. Some East Germans associated excessive use of the informal with the various state functions and in private conversation the threshold for breaching the formal/informal divide was higher. Surveys after 1993 about the use of the informal noted that Germans from the GDR tended to use the informal more reluctantly than their Western counterparts. This was one of the myriad legacies of the GDR after the *Wende*, but such observable differences tended to be much more the exception rather than the rule. | [
"From 1952 onwards, East Germany started to construct a fortified Inner German border to separate it from West Germany. From 1961 the Berlin Wall also divided the city of Berlin into two. Most of the wall was demolished in and after 1989.\n",
"The fall of the Wall marked the first critical step towards German reu... |
what is the difference between being found guilty and being convicted? | A conditional discharge is a type of plea deal. Essentially, you admit that you committed the crime in question and, in exchange, the judge agrees that if you fulfill certain conditions (typically completing a rehabilitation or therapy program) then the charges will be dismissed. If you don't fulfill the conditions you agreed to, then the you're re-arrested, formally convicted of the crime, and sentenced to jail.
Wikipedia's phrasing on it is really bad. If you get a conditional discharge then you have not been *found* guilty. You've *admitted* to guilt, but a court hasn't actually made any official judgement on your guilt or innocence. Essentially, the court has just said that if you fulfill the agreed upon conditions then its not actually worth prosecuting you for the crime. | [
"In law, a conviction is the verdict that usually results when a court of law finds a defendant guilty of a crime. The opposite of a conviction is an acquittal (that is, \"not guilty\"). In Scotland and in the Netherlands, there can also be a verdict of \"not proven\", which counts as an acquittal. There are also c... |
why is some glass not allowed near open flames or it shatters (display candles, etc) yet some glass like scientific beakers can withstand flames directly on then when all glass is made with heat? | Some glass is scientific / pyrex (boron + silica ) It has a low coefficient of expansion over a thermal range, thus it does not crack.
Most ordinary glass is Soda Lime ( silica + soda ash + limestone ) It has a lower melting temperature and has a greater coefficient of expansion, the glass cannot locally tolerate the expansion caused by heat, so it cracks / shatters. | [
"Heat-strengthened glass can take a strong direct hit without shattering, but has a weak edge. By simply tapping the edge of heat-strengthened glass with a solid object, it is possible to shatter the entire sheet. \n",
"The temperature differential that borosilicate glass can withstand before fracturing is about ... |
why is data still compressed? | Most cameras now allow you to save uncompressed ("RAW") photos.
Compression lets you download photos much faster, and use less of your data plan if you have limited data.
Compression for videos is still a necessity if they are to fit onto standard media, and allows one cable or satellite to carry far more channels. | [
"Compression is useful because it helps reduce resource usage, such as data storage space or transmission capacity. Because compressed data must be decompressed to use, this extra processing imposes computational or other costs through decompression; this situation is far from being a free lunch. Data compression i... |
why are rockets launched from places like cape canaveral and not high up in the mountains? | Cape Canaveral has two very large advantages for launching rockets.
* 1: It's near the equator, the spin of the earth gives a boost which helps get the rocket to orbital speed
* 2: It's near the sea, so any debris or stages that fall back to earth dont hit any populated areas. It is also easy to deliver large rocket parts by sea, as opposed to getting them up the side of a mountain | [
"Cape Canaveral was chosen for rocket launches to take advantage of the Earth's rotation. The linear velocity of the Earth's surface is greatest towards the equator; the relatively southerly location of the cape allows rockets to take advantage of this by launching eastward, in the same direction as the Earth's rot... |
how does the nordic model of economy work? | In Norway, things which everyone needs, like food, shelter, and medical care, are provided to everyone via a robust social welfare system. Things which people want, but do not need (basically all consumer items) get provided by the capitalist markets. There are some distinct advantages of this, including (but not limited to) vastly superior healthcare outcomes for a little over half the cost seen in the US, very low poverty rates and attendant very low violent crime rates, and, in general, happier people. The advantages of this to a capitalist market are huge. People spend way less time off sick, as they actually get quality healthcare and will not fear a bill until whatever they are sick with kills them. Happy people also buy more stuff, and people with money they can afford to spend can also buy more stuff. Capitalism gets along just fine with socialism. | [
"The Nordic model comprises the economic and social policies, as well as typical cultural practices, common to the Nordic countries (Denmark, Iceland, Finland, Norway, and Sweden). This includes a comprehensive welfare state and multi-level collective bargaining, with a high percentage of the workforce unionised, w... |
When did Lincoln become a folk hero and when did he start to be considered the best president in many people's minds? | Arthur Schlesinger Jr. conducted a survey of historians that resulted in a ranking of the presidents in 1948 for *Life* and another in 1962 that appeared in [*The New York Times*] (_URL_0_). Both surveys ranked Abraham Lincoln at #1 followed by George Washington and Franklin D. Roosevelt.
| [
"Schwartz argues that Lincoln's American reputation grew slowly from the late 19th century until the Progressive Era (1900–1920s) when he emerged as one of America's most venerated heroes, even among white Southerners. The high point came in 1922 with the dedication of the Lincoln Memorial on the National Mall in W... |
if i'm in a coma for x years, am i x years older? | You're physically 16 but mentally still 5.. Idt you would be capable of driving in that case.. | [
"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... |
how were metal chains made before we had welding machines? | Blacksmiths would heat the metal, and then hammer weld. You beat two pieces of metal with a hammer, and they will weld together. Lot's of info on Youtube about this type of welding. | [
"Welding lead or 'lead burning' was much more common in the 19th century to make some pipe connections and tanks. Great skill is required but can be quickly learned. In building construction today some lead flashing is welded but soldered copper flashing is much more common in America. In the automotive body collis... |
How much energy is lost in an internal combustion engine through the sound that it makes? | The math isn't overly complex, but the short answers is "not much". Sound doesn't take a lot of energy to produce, even at the volume a car produces before the muffler. A few hundred watts at most. A car engine is in the range of a few hundred kilowatts, so only roughly 0.1% of the cars power is turned into sound. Most of the loss is in the form of heat that's pumped out to the radiator. An engine that is designed to hold all that heat in is much more efficient, but the temperatures would destroy the engine unless it was made of some exotic heat-resistant material. | [
"Theoretically, detonative combustion, (i.e. that which happens at speeds above the speeds of sound), is more efficient than the conventional deflagrative combustion by as much as 25%. If this theoretical gain in efficiency can be realized, there would be a major fuel savings benefit. Because the combustion is supe... |
Why were the stairs in American vernacular houses behind doors? | Heat rises up stairwells. One reason to have a door on a stairwell would be to keep the heat (from a fireplace or a stove) on the ground floor, instead of rising up the stairwell. This would keep the ground floor warmer.
This would be particularly useful if the stairwell went up from one of the main rooms in the house, rather than from some separate hallway (which could be closed off from the main rooms by doors). | [
"The front door is an excellent example of doors characteristic of the Victorian era. It achieved two purposes: decorative but also to allow the passage of natural daylight. Almost all the doors in this Museum have unique majestic-style characteristics not found in doors in the capital city of San Juan, where doors... |
I often see a spider walking a cross a web line between two trees. How did they get the web to the other side to begin with? | The spider lets out an adhesive thread into the wind. Usually it does this upwind of an object suitable for this. When the thread adheres to the surface, the spider then goes across the thread while letting out a tougher non-adhesive line. | [
"The web, with its shelter at the centre, is easily identifiable. The leaf curling spider cleverly weaves a leaf or other object into the centre of its web as a hide-away from birds and other predators. Leaves are twisted along their length to form a funnel, (sometimes with a silk wall on one side, if necessary) th... |
What factors primarily determine if a shoreline is rocky or sandy? | It has to do mostly with how long the waves have been washing over and corroding the rock over time. The most common component of sand is quartz, which ranks a 7 on the MOHS Scale of Hardness, meaning that the amount of time it would take to break down into sand would be significant. The longer the waves have worked at it, the finer the grains become. | [
"Sandy beaches are dynamic habitats, with change mostly driven by wave action. These habitats provide a home to hardy and well adapted organisms. The local dunes are part of a mobile dune system in which sand is transported in the littoral and longshore zones and is trapped by vegetation, causing fore-dune developm... |
how rough seas come about. | Wind adds energy to the sea by pressing on it, which makes the waves we know and love at a perpendicular angle. Like sticking your hand in the water and the waves radiate out. Harder winds mean more pressure in the water mean higher waves, especially when the wind is constant. There are also a number of forces that make water naturally more turbulent like temperature and salinity differences in the water
The sea doesnt usually get THAT bad like in movies with the 100+ foot waves but rogue waves are a real and present danger in some areas, like the horn of Africa | [
"The direct source of inspiration for \"Rough Waves\" may have been the work of the artist Sesson Shukei (), whose still-extant paintings include a number of dynamic and mysterious images of sea waves, among them \"Egret, Moon, and Wave\" and \"The Wind and the Waves\". \"Rough Waves\" also reflects the influence o... |
What happens physiologically during exercise that can help us not only prevent osteoporosis, but even cause an increase bone mineral density? | The remodeling of the bones is very responsive to mechanical stress. When you exercise, you place stress on the bones, and they respond by laying down more bone matrix, thus increasing bone density.
Astronauts in space are not experiencing the same gravitational pull from the earth that they normally would. Therefore, when they are out in the zero-gravity environment of space, their bones are experiencing much less mechanical stress than they are on earth, and their bones respond by decreasing the amount of new bone matrix they lay down. | [
"Several other studies have found that osteoporosis (decrease in bone density) and increased risk of bone fractures are associated with hysterectomies. This has been attributed to the modulatory effect of estrogen on calcium metabolism and the drop in serum estrogen levels after menopause can cause excessive loss o... |
why is this baby crying? | i would think it was the subject matter of the song (kinda sad song) and the kid knows that based on either the mother's facial expressions/body language or by the tone of voice. Kids react to the mother's emotions very easily. | [
"Cry Along with the Babies is an EP by American rock band The Babies, released on January 10, 2012 by New Images Records. It features acoustic demos recorded in 2010 and early 2011 by Cassie Ramone and Kevin Morby in between tours and studio recording sessions. \"On My Team\" and \"That Boy\" were later included in... |
why is it so hard to sleep in silence once you get adjusted to a white noise? | Your environment has changed, so you become hyper aware. It's the same concept as when you first move out from your parents or get a new job. It's different from the norm so your mind pays more attention to it's surroundings as a survival mechanism. | [
"Noise can make sleeping difficult on occasions, whether from snoring, talking and social activities in the lounge, people staying up to read with the light on, someone either returning late from bars, or leaving early, or the proximity of so many people. To mitigate this, some wear earplugs or eye-covering sleepin... |
How historically accurate is the series "Empresses in the Palace/The Legend of Zhen Huan"? | > What benefits would a concubine receive from being elevated to various ranks (First Attendant, Lady, Noble Consort etc)? Is it only for prestige, or were there practical benefits as well?
Believe it or not, being empress/consort/concubine was actually a full time job, as they were paid salaries from the emperor's private treasury, received subsidies and tributes, and various other items such as gold and silver ornaments, jade decorations, porcelain, bolts of silk, and even day to day items such as tea pots, chamber pots, and saliva pots. Volume 16 of the *Guo Chao Gong Shi* compiled in the Qianlong reign lists all these things in detail, but for the sake of simplicity, I'll only list their salaries and the number of serving girls assigned to them.
* Empress Dowager: Gold - 20 taels, Silver - 2,000 taels, 12 maids
* Empress: Silver - 1,000 taels, 10 maids
* Senior Imperial Consort: Silver - 800 taels, 8 maids
* Imperial Consort: Silver - 600 taels, 8 maids
* Consort: Silver - 300 taels, 6 maids
* Imperial Concubine: Silver - 200 taels, 4 maids
* Noble Lady: Silver - 100 taels, 3 maids
* Chang Zai: Silver - 50 taels, 2 maids
* Da Ying: Silver - 30 taels, 1 maid
In addition, the construction of their palaces, the court apparel they wore, what kind of food they ate were all regulated according to their rank. So yes, there was a lot of practical benefit to being elevated in status.
> Multiple times in the series, characters were ordered to take their own lives rather than be killed via capital punishment. Why? What's the logic/reason behind this?
Death by suicide was considered a much more noble way to die than being beheaded, as it preserves the body as a whole for the afterlife and it avoids the humiliation of a public execution. There were different kinds of suicide, with hanging and poison being the most common. Several important figures in Chinese history, such as Zhangsun Wuji, Princess Taiping, Imperial Consort Yang, Nian Gengyao, He Shen were executed via forced suicide.
> Herbalism is a strong theme throughout the series. Is there historical evidence of concubines or other Imperial members using herbs, remedies, poisons etc against one another, or is this pure fiction? For instance, one concubine laces another's ointment with musk in order to induce a miscarriage.
Not too sure about the Qing, but in the Ming there were instances of poisoning concubines to induce miscarriages. Chenghua Emperor's concubine Lady Wan was said to have poisoned other concubines, so nobody dared to tell the emperor that he had a son (for fears that the son would be poisoned). Madam Ke, the Tianqi Emperor's wet nurse, was said to have done the same. This theme is quite popular in Chinese historical dramas though, so it's probably highly exaggerated here.
> At one point, a concubine is burning offerings for her dead brother, and her servant cautions that doing so within the palace walls is forbidden. Why is this?
It was considered inauspicious and offensive to place offerings to dead people in the palace where the emperor might spend the night. | [
"The Empress of the Dynasty is a Taiwanese television series based on the life of Wu Zetian, the only female emperor in Chinese history. Directed by Li Yueh-fung and produced by Lin Hui-chun, the series starred Angela Pan as Wu Zetian. It was first broadcast in Taiwan on CTV from 18 November 1985 to 10 January 1986... |
why do episodes of animated shows take so long to make? | You need to draw those characters, animate it per frame per scene. Afterward, quality check to ensure it follows the script; otherwise repeat the process again; then only voice over with voice actors / actress. | [
"The Animation Show of Shows is a traveling selection of the year's best animated short films, curated and presented by Acme Filmworks founder, Ron Diamond. It began in 1998 with the aim of showing the most original, funny, intelligent short animated films from all over the world and presenting them at the major an... |
why does it feel so orgasmic when you insert a cue tip into your ear? | Do you mean queue tip? | [
"In addition to nerve endings, pleasure from anal intercourse may be aided by the close proximity between the anus and the prostate for males, and vagina, clitoral legs and anal area for females. This is because of indirect stimulation of the prostate and vagina or clitoral legs. For a male insertive partner, the t... |
if i die in a car accident alone, how is my next of kin identified and contacted? | There are a lot of ways they could work it out.
Firstly, your car is going to be registered, most likely to yourself or your wife. Whilst your numberplates may be damaged, they're unlikely to be completely unrecognisable (especially if police use extra information such as make/model). Also, at least where I live all cars also have the same details on the engine block, which would be bloody hard to destroy. I'm not sure about your particular state, but where I live car registration will give an address as well as a name and next of kin details once they look up my license.
Secondly, you'll likely have at least some form of ID on you, credit card, drivers license, gym membership, whatever. If your car is unidentifiable, they can use these to at least get your name. They'll probably call the bank or gym and get an address from them if your ID doesn't have it.
For both of these points, first responders will now have your name and address, or at least your name. Your name may well be enough to find links to your family which they can then follow.
Finally, if you, your car and your wallet are all destroyed beyond recognition, your wife is probably going to notice when you don't answer her calls, and you don't come home. She'll then put in a missing person report, which will describe your normal day. Police will then follow this, (eg, normal route to work, any car crashes? Did he show up at work, lets ask his boss, when did he leave? etc) and will be very likely able to link the missing person report your wife filed, and the car crash on the I-35 with John Doe.
They will then call your wife in to identify you, and provided that you didn't get T-boned by a petrol tanker which then exploded your remains will likely be recognisable. Certainly things such as your wedding ring, key chain and others may well be largely undamaged.
I'm not a police officer, so there may well be some other avenues which I've missed. Certainly, the car rego and the ID in your pocket will be the first steps. | [
"As of June 2018, a total of eleven people have been killed on the road since it opened. In June 2012, one person died and four others were injured in a wreck near Avalon Drive, the same location where two young women were killed in December 2011. More recently, on September 28, 2014, another person died in a wreck... |
how does sweden get things done if they have 6 hour work days, 25 vacation days per year, etc? | It's been shown that the longer and harder someone is made to work, the less work they actually get *done,* because they get tired and work slower, get sick more easily, miss days, etc. If you let people rest more often and take time off, they become far more productive. | [
"In Sweden, the standard working week is Monday to Friday, both for offices and industry workers. The standard workday is eight hours, although it may vary greatly between different fields and businesses. Most office workers have flexible working hours and can largely decide themselves on how to divide these over t... |
Is it better in the long term for a car to be "warmed up" in cold weather before using it? | Michigan native, automotive engineer (mechanical) and general gearhead here. To expand on what botanist said:
Start the engine and give it 30 seconds of running to build oil pressure. It will build faster than that, but it's fine. If your car is covered in snow/ice, take the 5 minutes to get it all off.
Drive away, but be gentle on the gas pedal. Try not to rev beyond 2,000rpm until the temperature gauge is in the 'normal' range. This means just up off of 'cold'.
After that, drive normally.
If you idle for extended periods, you're getting 0mpg. Idling doesn't generate as much heat as driving down the road, so your car warms faster while underway. Also, modern cars have EGR (exhaust gas recirculation) for emissions purposes. Idling an EGR-equipped engine extensively will foul up your oil with combustion byproducts and acidify the oil prematurely. So really there's no reason to leave your car idling longer than 5 minutes or so. | [
"To cool the air it used latent heat (in other words, cooling by water evaporation). Water inside the device evaporates and in the process transfers heat from the surrounding air. The cool moisture-laden air is then directed to the inside of the car. The evaporate \"cooling\" effect decreases with humidity because ... |
why does porn stream better on my phone over 4glte than it does on my home internet with 50/50/mbps? | I doubt you have a symmetrical home connection. But even if you do, well.. are you using WiFi?
"Standard" WiFi (802.11g) can only obtain a maximum link speed of 54mbps whereas 4G LTE supports up to 100mbps. WiFi has many variables that may affect performance -- notice how 4G cell towers work for kilometers while WiFi works at maybe hundreds of feet. 4G is an expensive technology which requires a much more advanced infrastructure.
If you are talking about using a desktop computer, make sure your router, switches, and wiring support gigabit. There could be congestion on your home network caused by other devices as well. If you have VOIP phones or HPNA TV, that could degrade QOS as well.
Background: I work for a managed service provider and have had advanced experience with technology for over 10 years. | [
"Due to the large size of the files being downloaded, the service required a broadband internet connection capable of sustaining transfer speeds of 800 kbit/s. A 2-hour filme might have taken 7 hours and 20 minutes to download using a 750 kbit/s DSL/cable connection or 1 hour and 50 minutes with a 3.0 Mbit/s DSL/ca... |
WWII and Reinforced Units. | You are correct that reinforced units had extra assets attached, before making an attack on an important target. In the US Army, every Corps and Army had a pool of independent Armor, Artillery, Engineer, Recon and Tank Destroyer battalions. These battalions could be plugged into a division making a major objective attack. For example, the US Army XV Corps only had one infantry and one armored division. It also had eight battalions of artillery, five battalions of armor, five battalions of tank destroyers, three battalions of Recon and six battalions of engineers.
Source: "Panzer Leader: Rules, Designer's Notes and Campaign Data" by Dave Clark and Nick Smith (1974) | [
"The 10th Mechanized Corps was a formation in the Soviet Red Army during the Second World War. Initially formed in March 1941 in response the German victories of 1940 it was attached to the Leningrad Military District, & held in reserve near Leningrad Fortified Region in Soviet Union It was under the command of Maj... |
how do "safe spaces" relate to the first amendment? | You might need to add more context.
Remember that the first amendment essentially says you won't be arrested for saying something (with a few exceptions).
If you're talking about censorship, and it's not happening from the government, they are free to censor. If it's happening from the government, it could be a first amendment issue if they can't prove something like obscenity or public safety. | [
"The Fourth Amendment to the U.S. Constitution protects the people's right \"to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures\". However, when applied to information stored online, the Fourth Amendment's protections are potentially far weaker. In part, this is b... |
Before the Big Bang occurred were the fundamental laws governing the universe present or were these created simultaneously with the expansion? | It's unclear whether the phrase "before the big bang" can even be given rigorous meaning, let alone what physics applies to anything that can be given such a description. | [
"The Big Bang itself had been proposed in 1931, long before this period, by Georges Lemaître, a Belgian physicist, who suggested that the evident expansion of the Universe in time required that the Universe, if contracted backwards in time, would continue to do so until it could contract no further. This would brin... |
After France was liberated in WWII, how prevalent were reprisals against people who collaborated with the Germans? | The situation in France is a bit complicated by the fact that part of France was actually a collaborationist puppet state of the Germans Reich, so-called [Vichy France.](_URL_0_) This meant that a lot of people were involved in some kind of dealings with the Germans, including very high-ranking officials, making the punishing of all of them a difficult and delicate issue.
Having said that, let's have a look at three neighbouring countries to see how the reprisals evolved in each: the Netherlands, Belgium and France.
**Mob violence**
Immediately after liberation, irate mobs hunted down and rounded up many perceived and actual collaborators for some old-fashioned street justice, ranging from public humiliation to executions: women who had relationships with Germans were shaved and paraded, often [naked](_URL_1_) (NSFW), through the streets, or raped; in Belgium collaborators were exhibited [in the animal cages of Antwerp Zoo](_URL_2_); collaborators' houses were ramsacked, looted and burned; many were beaten up and dragged off to former camps or other collection points formerly used by the Nazis to round up Jews and political prisoners (the Velodrome in Paris). This phase was particularly brutal in France, where it is estimated that 10,000 collaborators were executed without trial around the time of the liberation.
**Legal reprsisals**
Once the immediate post-war chaos died down, proper trials were held in all three countries. Relatively few of these trials resulted in the death sentence, and many death sentences were commuted to (life in) prison sentences. Many more people were sentenced to prison, in the majority of cases for a relatively short period. The most widespread form of punishment was actually the loss of civil rights, mainly the right to vote and to be employed by the state. Prosecutions in Belgium were particularly severe because collaboration issues were intertwined with the tensions between the two language communities (Flemish nationalist parties collaborating with the Germans was seen as more reprehensible than the mainly economic and opportunistic collaboration in Wallonia).
**Figures up to 1948**
War criminals were (and are) being prosecuted sporadically right up to the present day, but the main wave of prosecutions is generally accepted to have subsided by 1948. It was also at this point, after the righteous popular anger had died down somewhat, that amnesty laws were starting to be implemented.
||France|Netherlands|Belgium|
|:--|--:|--:|--:|
|executed|791|36|242|
|death sentences commuted (or pronounced *in absentia*)|6,246|102|2,698|
life in prison (includes commuted death sentences)|4,334|268|3,044
|prison sentences > 5 years|10,820|7,849|15,010
|prison sentences < 5 years|22,883|43,302|30,244
Sources
Huyse, Luc. "Waarom België ziek is van zijn jaren veertig." Bijdragen tot de Eigentijdse Geschiedenis/Cahiers d’Histoire du Temps Présent 10 (2002): 185-193.
Aerts, Koen. "De Kroon ontbloot: genadeverlening bij de doodstraf tijdens de zuiveringen na de Tweede Wereldoorlog." BIJDRAGEN TOT DE EIGENTIJDSE GESCHIEDENIS= CAHIERS D'HISTOIRE DU TEMPS PRÉSENT 11.17 (2006): 15-47.
Rousso, Henry. "L'épuration en France: une histoire inachevée." Vingtième siècle. Revue d'histoire 33.1 (1992): 78-105.
Belinfante, August David. In plaats van bijltjesdag: de geschiedenis van de bijzondere rechtspleging na de Tweede Wereldoorlog. Amsterdam University Press, 2006.
| [
"When Allied forces liberated Normandy and Provence in August 1944, a victorious rebellion emerged in occupied Paris and national rejoicing broke out, as did a maelstrom of hatred directed at French people who had collaborated with the Germans. Some Germans taken as prisoners were killed by the resistance.\n",
"A... |
/ why do baby animals have different fur than adults do? | The smaller animal has a higher surface area to volume ratio so would lose more heat and possibly needs better insulation. It also probably doesn't need the sort of tough fur able to withstand hunting prey through undergrowth etc. Adult animals still have soft fur layers for insulation but more durable hairs growing through to provide a tougher outside layer. | [
"Infants are born with bright orange coloured fur, which fades to black throughout the period of infancy lasting several months. It isn't known why their coats are so conspicuous, but current hypotheses suggest it may elicit attention, protection and caregiving by adults.\n",
"The fur, which is soft, dense, and t... |
why do professional basketball games often end with close scores despite bigger gaps earlier in the game? | Some might say it is because there is score fixing going on whereby individual players/refs are paid to keep the score close to the betting line. They might accomplish this by intentionally missing free-throws, calling fouls on key players, or playing shoddy defense. If you are a conspiracy theorist (or perhaps a realist in this case) your answer might be found here. Disregarding that however...
1) Players who generally spend much of their time on the bench might get to play...they are fresh and are trying to impress their teams management as well as managers of other teams so they perform well against the other teams starters who know the game is well in hand.
2) Teams who are up by a large margin know that they can give a bit of that lead back and still win. They are more interested in keeping the clock running than in scoring or playing lock-down defense so they do not foul or risk charging fouls which stop the clock and prolong the affair. The winning team will also tend to wait as long as possible in the shot clock before shooting which may result in them taking a lower probability shot. But again, they have spent valuable time.
3) Many NBA teams are fairly equally matched and basketball is a momentum game. Sometimes scoring comes very easily for a team and then, often for no reason that is obvious, that momentum switches and that same team can't find a bucket. If you assume a player makes 50% of their shots, you can substitute flipping coins as an analogy. Flip a coin 100 times and record your results. While you will probably end up somewhere around 50/50 heads/tails, there will likely be some stretches where you got several heads in a row and then later a period where there was a run of tails. Obviously, in basketball this would be akin to a large lead evaporating.
| [
"Due to the limitations of the system, a number of variations and changes were made to how \"Basketball\" plays versus a real-life game. Gameplay is on a simulated regulation-style full court, whereas traditional three-on-three basketball games typically use only a half-court setup. There are no foul shots in the g... |
How does the location of the brake caliper on the disc affect braking performance? | It doesn’t really affect performance too much. The main deciding factor on where they go is the location of the steering and how the tie rods connect. If the steering rack is in front of the wheel the brakes go on the back, and vice versa. As for the rear wheels, it usually depends on how the suspension is attached. They kinda just fit wherever there’s space. That’s usually around the same spot as the front, or mirrored from the front. Some cars use drum brakes in the rear, which sit right in the center, so there’s no issue there. | [
"A disc brake is a type of brake that uses calipers to squeeze pairs of pads against a disc or \"rotor\" to create friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hold it stationary. The energy of motion is converted into waste heat which must... |
why do some websites and programs seem to not be able to process apostrophes and instead replace it with a series of nonsensical characters. for example: instead of "john's", the site would show "john’s". | Issues like this are usually due to mishandling of character encoding.
Inside computers all data is stored a series of numbers. Basically, the old way of storing text is to use exactly one byte (eight bits; each bit is a 0 or 1) for every single letter. This is what ASCII is; in ASCII the numbers from 0 to 255 each correspond to a letter, for example the number 97 is lowercase a.
The issue with this is that there are a lot more than 255 different characters that people want to use in text; even many Western European languages didn't have some of their symbols available. Asian languages, Eastern European, Hebrew and so on don't have any of their letters available in ASCII.
This problem is solved by having a much larger range of letters called [Unicode](_URL_0_). Using this scheme they have an extremely large space for symbols, which allows them to have characters for silly things like smiley faces and snowmen. There are different ways for storing the Unicode characters; some of them just always use 16 or 32 bits for each character but that ends up not being very efficient for most Western-biased usages where almost all of the letters are from ASCII and only a few are "special".
The most common way of encoding the charaters is called [UTF-8](_URL_1_) which is the same as ASCII for characters numbered 0 to 127, but the other characters use multiple bytes. UTF-8 has some nice properties that are beyond what I will mention here, but the important thing is if you accidentally try to read UTF-8 text as ASCII, any of the simple letters or numbers will look normal.
The particular issue you are seeing is usually because they didn't use the actually ' character, they used what is called "smart quotes" that are curved in one direction or the other (it looks like this: ’ or ”, it is more obvious in a different font).
So the server tries to tell your browser to show a curved quote, it uses a UTF-8 encoding that is 2 or 3 bytes. Due to some sofware misconfiguration, the browser thinks that it is ASCII so it takes each of those bytes and tries to show them each as letters, which ends up with the weird unrelated symbols. | [
"To make typographic apostrophes easier to enter, word processing and publishing software often convert typewriter apostrophes to typographic apostrophes during text entry (at the same time converting opening and closing single and double quotes to their standard left-handed or right-handed forms). A similar facili... |
Are humans built to 'mate for life'? | I approved this question, not because it is a good question, but because it is a bad one. We can learn from bad questions!
There's no "intention" in evolution. Anthropologically, we see a tendency for humans to form pair-bonds like many other animals. But, we also see infidelity and we're biologically capable of many social arrangements as well as rape, so that's pretty much as far as it goes.
I hope one of our anthropologists adds more detail :) | [
"Although from an evolutionary perspective women are usually the choosy sex, if a human male has the desire to reproduce he may seek certain qualities in a potential mate who could be the mother of his offspring. Humans have the ability to rely on biological signals of reproductive success and non-biological signal... |
what happens in our brain, when we forget what we wanted to do while starting to do the action? | Our brain reinforces pathways we take more than once. Often what happens when we forget what we wanted to do while starting to do something is that a more reinforced brain pathway is triggered when we start the action, causing us to forget the rest once it leaves short term memory.
Sort of like the challenge of patting your head while rubbing your stomach. | [
"Mind-wandering (sometimes referred to as task unrelated thought, or, colloquially, autopilot) is the experience of thoughts not remaining on a single topic for a long period of time, particularly when people are engaged in an attention-demanding task.\n",
"Research has also shown that doing difficult counting ta... |
when dry clothes are hanging on the radiator, what happens to all that heat energy? | Some of the heat is used to convert the water in the clothes to water vapor drying the clothes. Some of the heat is simply blocked by the insulating factor of the clothes. | [
"BULLET::::- When clothes are hung on a laundry line, even though the ambient temperature is below the boiling point of water, water evaporates. This is accelerated by factors such as low humidity, heat (from the sun), and wind. In a clothes dryer, hot air is blown through the clothes, allowing water to evaporate v... |
what are collateralized debt obligations (cdo) and how do they work? | To break it down by terms, you have a **debt** that someone is **obligated** to repay, and this debt is secured by some kind of **collateral**. This is a fancy way of describing a very common situation like someone buying a house. When you buy a house, you take out a loan (the debt) and you must repay it back with interest (the obligation) or else you lose your house (the collateral).
Now the term CDOs usually refers to when a bank takes a large number of mortgages and groups them together. The reason they do this is because it should average out the risk. If you have a 1 person paying a mortgage and they default, you are in a bind. If you have 100 people all paying mortgages and 10% default, you are still making money off of the other 90%.
Now here's the trick -- people take on debt to buy a whole lot more than just houses. You might have a business take out a loan to buy new machinery, you might have students taking out loans to pay for college, etc. If you properly group all of these things together, you can make a diversified, lower risk investment. The idea is that while some people might struggle to pay for their homes, those same conditions might make it easier for certain businesses to pay off their debts.
The problem is that during the housing boom a huge number of these *weren't* diversified this way, they were simply a whole lot of mortgage debt. This meant that when people were unable to pay their mortgage, the investments were no longer a steady source of income. Likewise once the values of houses dropped, the collateral these loans were based on was also not worth as much as you would hope. | [
"A collateralized debt obligation (CDO) is a type of structured asset-backed security (ABS). Originally developed as instruments for the corporate debt markets, after 2002 CDOs became vehicles for refinancing mortgage-backed securities (MBS). Like other private label securities backed by assets, a CDO can be though... |
what is this white fluid covering my knee scratch | Its probably Lymph.
> Lymph is a clear-to-white fluid made of: White blood cells, especially lymphocytes, the cells that attack bacteria in the blood. Fluid from the intestines called chyle, which contains proteins and fats.
Basically its stuff that prevents infection. | [
"Bleeding or flushing is shiny, black surface film of asphalt on the road surface caused by upward movement of asphalt in the pavement surface. Common causes of bleeding are too much asphalt in asphalt concrete, hot weather, low space air void content and quality of asphalt.\n",
"Symptoms of a sprain or tear of t... |
how do videogame textures work? | You know how before you recycle a cardboard box, you have to flatten it out?
Same idea in a 3d mesh; you take all of the faces and lay them out on a flat surface where the textures get added on.
The difference being that with a box, the goal is to get them flat, but with a 3d mesh, the goal is to get everything in a certain area, so with the box you probably don't cut one side off and put it over by an unrelated side where you have some room on a 2d plane.
In the 3d meshes I've made, you didn't *have* to keep everything connected (ex: if you were modeling a human skin texture for a body mesh, you could put both arms in the lower-lefthand corner of the file, then the backs of those next to them until you got to the lower-right, without regard for where it would normally go if you tried to wrap it back together (the program would mark where each part of the 3d model got its coloration/texture from and pull from those coordinates of the image file), so in a way it's not *quite* a stretchy piece of plastic, but more of a cut-out sheet of stretchy plastic that you can glue to your surface to add coloration to it in more detail than just choosing 1 color for the whole bit. | [
"Inevitably, certain sides of some objects (e.g. walls) in a game scene will never be visible to the player during normal play. The person making the map can apply the caulk texture, instead of a normal texture, to these surfaces when building the map. The surfaces become invisible in-game and if compiled into a Bi... |
why do led lights look jittery or like they're strobing when you look at them quickly? | They look like they are strobing because (for most of them) on mains power they actually are! Much like when whatching TV, however, something called ”persistence of vision” smooths it all out for you. When blinking or looking away quickly your brain "preserves" what you saw in that instant and you can spot it. You can also see it when something is moving quickly across your vision.
Similar stuff happens when you dim LEDs (like LED car taillights when the brakes aren't on), though much, much faster through something called PWM. The LEDs are switched on and off really quickly - when they are on for half the time they look half as bright.
In theory PWM is too fast to be perceivable (when done right) but it seems a lot of people are actually sensitive to it!
You can also get strobing from HID headlights because they often use AC to get the thousands of volts they need to ignite.
*This bit goes a little beyond ELI5 but hopefully still helps. My inbox kinda exploded and I've tried to answer repeated questions in the edits.*
Strobing is (historically) very common with LEDs driven from mains AC. You can often see the effect if you wave your hand back and forth while focusing on a stationary spot - instead of smooth motion blur you can see a series of hand images, like stills from a movie. Cheap camera phones also sometimes show it. So why does this happen with LEDs but not other lights?
In your mains AC, the voltage alternates from positive to negative and back again 50 or 60 times per second. That means that 100 or 120 times a second the voltage is exactly **zero.** Zero voltage, zero power.
In traditional incandescent lights there is a fillament which is heated super hot to provide light. This fillament takes time to cool down - much longer than the mains supply takes to go through zero - and so it can stay hot, keep putting out light, and there is (almost) no flicker.
In LEDs, there is no fillament to heat and they react *very* quickly. When the voltage to them starts to drop towards zero, the lights dim and turn off, coming back on again as it voltage goes back up. As this is happening at 100 or 120 Hz, most people wont notice it.
Cheap or traditional triac based dimming can seriously exacerbate the issue with mains strobing.
In higher quality power supplies for LEDs, they use "smoothing capacitors" and/or purpose designed LED drivers to help the LED stay lit through the low/zero volt bits and this reduces the strobing effect.
Incidentally, flourescents also strobe (though to a lesser degree) and most video cameras have special software to help hide this.
Obviously with battery (DC) powered stuff, excluding dimming, there is no AC and so no strobing.
**E:** typos
**Late E2+:** Some battery powered things can use DC to DC transformers which can in turn cause strobing, so the above has caveats. LED car headlights may fall into this category.
I have assumed above that we are talking about incandescent replacement globes which almost always have a full bridge rectifier. For single diode lights (Christmas lights, dim indicators, or other decorative lighting) it is half the frequency and more noticeable.
The flicker many people mention in slow motion footage of car LED taillights is almost certainly PWM dimming for combo brakes/running lights. Brakes on, full power, running lights, dimmed.
**Regarding strobing headlights**, chances are they are HID lights not LED. HIDs need thousands of volts and have transformers (called ballasts) to get this, in turn meaning almost certainly an AC voltage being produced. Much like flourescent tubes, or arc lamps, there is no fillament to help it ride the zero crossing in the AC signal and they strobe. If it is absolutely LED then I would suspect it has to do with being a fancy matrix LED configuration which automatically controls the beam pattern (PWM?). Might also be DC to DC transformers at play.
I also found it really interesting how many people have issues with PWM lights. Common wisdom used to be anything above 1 kHz was impossible to see with the naked eye... the exact frequency used in PWM is kinda arbitrary though, apart from lower is easier. Nothing stopping someone using PWM at say 200 Hz instead, which might be where the issue lies.
If strobing bothers you the good news seems to be that a lot of newer high quality LED globes have switch-mode and/or smoothing built in, however it's not clear how to tell from the box. I did a search on Amazon and I couldn't find the right magic words. YMMV. If you have the chance to use them in person, at least one variety will stay on for a fraction of a second after you turn them off, so you might be able to look for this. Dimmable sorts might also be better. | [
"BULLET::::- Dimming: LEDs can very easily be dimmed either by pulse-width modulation or lowering the forward current. This pulse-width modulation is why LED lights, particularly headlights on cars, when viewed on camera or by some people, seem to flash or flicker. This is a type of stroboscopic effect.\n",
"LED ... |
Asking again about Egalitarian society in Prehistory | Generally-speaking, smaller non-state or non-complex groups (i.e. hunter-gatherer groups of say, 20-50 people) are considered egalitarian. This is not to say that there is no hierarchy at all, just that leadership is fluid and non-permanent (one person might hold sway for a while before people ignore them and begin to listen to someone else), and there is a strong ethic towards sharing amongst the group and against any one individual accumulating wealth. So there is leadership and there are hierarchies (based on age, experience, gender, etc.), but it is not entrenched the way that it is in more complex societies ("complex" referring to social organization, having different levels of leadership and whatnot).
But this egalitarianism idea has been paraded and lauded and romanticized for decades, even by anthropologists, but is often not well understood. It is a romantic ideal that probably never really existed.
We have no way to know directly how people organized themselves in prehistory, so we have formed these ideas by comparing what we think we know about ancient societies against what we know by studying living hunter-gatherers and smaller societies around the world. So all that is to say that this isn't really a historical question, it's one for anthropologists and for anthropological archaeologists (like myself). So I'd post this to /r/AskAnthropology to get other perspectives besides mine. | [
"Modern egalitarianism is a theory that rejects the classic definition of egalitarianism as a possible achievement economically, politically and socially. Modern egalitarianism theory, or new egalitarianism, outlines that if everyone had the same opportunity cost, then there would be no comparative advances and no ... |
does a leaf stay alive right after it is severed from the main plant body? if so, for how long? | Unfortunately, the term "alive" isn't really a well-defined term. Generally, something is "alive" if it has the following properties:
* Regulation of an internal environment;
* Composed of one or more cells;
* Converts food into energy, fuel into building blocks, and gets rid of waste;
* Converts more fuel into building blocks than the amount of waste it gets rid of;
* Changes over time in response to the environment;
* Responds to stimuli;
* Ability to reproduce;
For a leaf, the answer to this lies in the last one. Many plants have the ability to reproduce asexually via a process known as *vegetative reproduction.* Basically you can snip off a part of the plant and use that part to grow an entirely new one. If this plant you've taken the leaf from is one of those kinds of plant, the potentially you could say that the leaf is still alive.
If it is not, and the ability to reproduce has been eliminated, then the leaf technically isn't "alive" any more.
You raise a second sticky question with the "how long" which is basically "at what point is something that was alive considered dead?" This is also a hard question to answer. Technically anything that fails to meet the above requirements would be no longer alive (and therefore dead) but those properties aren't hard and fast.
To be safe, we would could say it is dead when it has *none* of those properties.
Separated from the main plant, we lose the last one and it can no longer reproduce. It will suffer from a lack of sufficient nutrients and can no longer convert fuel into building blocks faster than the rate its cells are dying. As key nutrients are used up, the ability to convert food into energy and fuel into building blocks is further interrupted and cell death speeds up.
Cell function will decrease until internal regulation and ability to adapt and respond to the environment is inhibited.
Once the leaf is no longer functioning, it will quickly fall prey to chemical breakdown by the elements or consumption by other organisms, and will cease to be composed of one or more cells. | [
"Plants are usually propagated by stem or leaf cuttings. The leaves are quite delicate and will readily break off the stem when manipulated. The leaves will stay alive for many days and roots will emerge after a few days.\n",
"After entering the plant through the leaves, the virus remains in the leaf cells for 8 ... |
What is the purpose of the imaginary component of the Riemann Zeta Function? | So, you've probably seen the usual definition of the zeta function. Namely zeta(s) = 1+2^-s +3^-s +...
Now, this is a function of a real number, s. Moreover, it is only defined, thus far, for s > 1, since the above series diverges otherwise. Clearly, for any such s, zeta(s) would be completely real. But, what if I wanted to extend the domain of my function. That is, I now want to let s be any complex number. Well, it turns out that the series definition works so long as Re{s} > 1. So I've already encompassed a great deal of the complex plane (which, by the way, is just the set of complex numbers. Imagine real part on the x-axis and imaginary part on the y-axis).
Let's keep going. Maybe you've seen this nice property of the Zeta function: (1-2^(1-s) )zeta(s)=1-2^-s +3^-s -4^-s +...
Which we can rewrite as zeta(s)= (1-2^-s +3^-s -...)/(1-2^(1-s) )
What's nice is that, because of the oscillating sign in this new series, it actually converges for more values than before. We now have a formula that works for Re{s} > 0 (though note that there is still a problem at s=1. This is a property of the Zeta function, not a shortcoming of our extension). So at this point, we've conquered the right half of the plane. To get the left half, we need the [reflection formula](_URL_0_), which gives zeta(s) in terms of zeta(1-s). I can't really explain why this formula is true, since the derivation requires a good bit of complex analysis. But, if you accept this formula, then you see we can now define zeta(s) everywhere (except at s=1).
Now, you may ask why I would want to do this. As you said, the Zeta function is very important in number theory, as many things in number theory can be expressed in terms of the Zeta function. Well, complex analysis is very good at extracting information from certain complex functions. Thus, by making the Zeta function into of these functions, we have all of the powerful machinery of complex analysis at our disposal. For example, zeroes and poles are important in complex analysis. Often times knowing them means knowing everything you need to know, hence why the Riemann Hypothesis is so important.
So, to answer your question, the original series definition that makes sense for number theory is completely real. It gains an imaginary component when we extend it to the complex plane hoping to gain powerful tools from complex analysis to help us. | [
"The Riemann zeta function is one of the most significant functions in mathematics because of its relationship to the distribution of the prime numbers. The zeta function is defined for any complex number with real part greater than 1 by the following formula:\n",
"The zeta function plays an important role in stu... |
I am an ordinary person in the middle of England in the mid 14th Century. What is the closest modern flavour of cheese to the cheese I would usually eat? | In the 14th century, parmesan (as just one example) was already being made and shipped potentially as far as England. In lowland areas of the northern Mediterranean these kinds of salty cheeses were produced and easily shipped compared to the kinds being made and consumed at higher altitudes. Aged cheeses were being produced not just in the mediterranean but further north as well. Cheese production was also somewhat commercialised at that point with Monasteries conducing cheesemaking operations on a larger scale than what you'd do at home. According to Paul Kindstedt's *Cheese and Culture*, the already well established cheesmakers came under grater economic pressures to improve their techniques, which allowed for an increase in production, but by then the variety between different types of cheese was already pretty significant. Things like ageing and different ingredients and different styles were already well established at that point.
Is there a reason you're asking about the 14th century specifically? You can read the first few parts of Kindstedt's book on Google Books, but not as far as the 14th century. Still, if you're interested in the earlier periods, you should be able to get a pretty good idea there. It's a pretty interesting book if you're a fan of both history and cheese, which I happen to be.
Source:
* *[Cheese and Culture. A History of Cheese and Its Place in Western Civilization](_URL_0_)* by Paul Kindstedt | [
"Most cheeses were initially recorded in the late Middle Ages. Cheddar was recorded around 1500 CE, Parmesan was founded in 1597, Gouda in 1697, and Camembert in 1791. Cheeses diversified in Europe with locales developing their own traditions and products when Romanized populations encountered unfamiliar neighbors ... |
how are street address numbers decided upon, if they apparently don't refer to an agreed upon distance unit? | In US cities, some central intersection is designated as 0. The first east-west cross street north of that is 100N. The first block south is 100S.
So if your address is 6407 N State Street, you're on State street 64 major cross streets North from the 0-0 intersection, and the seventh house north from the 6400 cross street.
In heavily gridded cities like Chicago these are pretty straightforward, but some curvier roads in curvier cities get sloppy.
| [
"Address numbers can be determined from the numbers or names of intersecting streets. Addresses on north–south routes, including exceptions from the numbering and naming system, follow the numbers of intersecting (or implied intersections of) numbered streets. For example, 2005 South Glebe Road would lie just beyon... |
why can 50 cents declare bankruptcy to avoid paying the woman even though he's got the excess money to give to her? | Is he pulling a Trump? | [
"On 12 January 2015, \"The Mail on Sunday\" reported that Anita Harris and her husband and manager Mike Margolis were, or were about to be, declared bankrupt by HM Revenue and Customs over historic tax arrears of £14,000 and £25,000 respectively. The bankruptcy order of 11 August 2014 was annulled when an IVA was a... |
what are the aggressions of iran that make the super powers want to isolate them? | InB4 the conspiracy nuts arrive and blame ze Jews lol.
They are essentially an Islamic Fundamentalist Dictatorship. Their leader threatens to revive the medieval crusades and they are actively seeking to develop nuclear weapons (topic that should be discussed in a dedicated thread because there have been false flags)
They are also a proxy state for Russia who funds them and supplies arms to them because the cold war never really ended | [
"On the international scene, it has been argued by some that Iran has become, or will become in the near future, a superpower due to its ability to influence international events. Others, such as Robert Baer, have argued that Iran is already an energy superpower and is on its way to becoming an empire. Flynt Levere... |
Does a high metabolism increase risk of cancer? | Biologist here; this actually happens to be the very topic of my research!
In short; amongst other reasons, yes. Indeed, if you take a look across multiple species - say, all mammals - you'll notice that going from wee mice to bloaty whales, mass-specific basal metabolic rate (the amount of energy you burn for every gram of tissue, say) decreases; as do cancer incidence rates ([graph here](_URL_0_); blue is specific metabolism, red; cancer).
Large mammals like whales and elephants have many orders of magnitude more cells than us (and have considerable lifespans), so you'd think they'd be riddled with tumours, succumbing to cancer quite readily - I mean, they have so many cells that could mutate, and an awful long time for them to do it, at first glance it's bound to happen sometime. Yet the opposite is true. This is known as [**Peto's Paradox**](_URL_3_), and to resolve this paradox we must somehow explain why large mammals are resistant to cancer.
There are several co-compatible answers to this. One of them is to do with their genetics (specific genes need to be broken to cause cancer; larger mammals often have many duplicates of these genes, so even if a few are knocked out, they still retain working copies and remain cancer free), another is to do with their metabolism.
I won't go into too much detail as the work is still under review for publication (and it's a bit maths-ey, blergh), but by building comprehensive computational models of mammalian tissue and by tweaking the dials that relate to metabolically-linked phenomenon (say, how often cells divide, the rate of production of damaging oxygen radicals etc. etc.), we can fairly accurately simulate and [predict lifetime risk of cancer incidence](_URL_5_)__*__ as a function of metabolism - and it lines up quite nicely with observed rates of cancer from mammalian veterinary reports. In a more ELI5 manner; by trying to give virtual whales lotsa' virtual cancer, we can see their metabolism is too slow for much cancer to really get going; which matches what we see in actual animals.
So yup, it seems the hypothesis that metabolism has a major influence on cancer risk seems valid, and can be quantitatively modelled - larger animals have slower metabolisms relative to smaller ones, and this helps reduce their cancer risk. I'd be happy to elaborate on the cellular-level mechanistic explanation for why (as you mention, cell division is one reason amongst many), but for a good review see Dang (2012) linked below!
**TL;DR:** Yup! Small animals with high metabolisms are almost walking tumours; big animals with super slow metabolisms are practically cancer free. Congrats, whales?!
_____
^**Sources:**
[^(Abegglen, L.M. Caulin, A.F., Chan, A. *et al.* (2015)^) ^(Potential Mechanisms for Cancer Resistance in Elephants and Comparative Cellular Response to DNA Damage in Humans. *JAMA*. 314 (17)^), ^1850-1860](_URL_4_)
[^(Caulin, A.F. & Maley, C.C. (2011)^) ^(Peto's Paradox: Evolution's Prescription for Cancer Prevention. *Trends Ecol Evol*. 26 (4)^), ^175-182](_URL_1_)
[^(Dang, C.V. (2012)^) ^(Links between metabolism and cancer. *Genes Dev*. 26 (9)^), ^877-890](_URL_2_)
_____
^(__*__ The black line here is observed cancer incidence rate across mammals, the individual blue dots are predicted incidence rates based on metabolic data for 600-odd mammal species, and the red line is the generalised linear model for that data - it basically shows that this simulation is very good at predicting cancer rates for almost all mammals taking into account metabolism alone, *except* for the very extremes (where the red line shoots up at the end)^) ^(- and it's in the very largest and very smallest of mammals that we're find all the genetic trickery, like duplicated cancer genes, that's making up for what their metabolism alone can't explain.)
| [
"In addition to these major risk factors there are also numerous other modifiable factors that are less strongly (i.e. 10–20% risk increase) associated with bladder cancer, for example, obesity. Although these could be considered as minor effects, risk reduction in the general population could still be achieved by ... |
what is it about guns that makes americans so worried? is it some eventual uprising that will sweep the nation, or what? | Europeans seems to fear guns (as they are small death dispensers), Americans seems to think of guns like a protection (as they are small death dispensers).
Guess it's a cultural thing. | [
"Other international commentators predicted little chance of tougher gun laws or changes to the U.S. gun culture. BBC's Washington correspondent Matt Frei wrote \"America is at its most impressive when it grieves and remembers. But will the soul-searching ever produce legislation and will it make schools safer?\". ... |
why radioactive material is dangerous | The definition of radioactive refers to the material being unstable at the atomic level and breaking down over time while releasing a spray of energetic subatomic particles. Those particles contain enough energy that they can knock electrons out of place in matter they interact with. And one such material is our DNA. Knocking out electrons causes the chemical bonds to weaken and sometimes break, damaging the genetic material encoded in the molecular structure. Your body has some DNA repair mechanisms but they're not perfect and over time accumulated generic damage can give rise to a mutant cell that divides out of control, thus forming a cancer. | [
"Radioactive substances are used widely in industry, medicine and research in Scotland. Uses can range greatly from the diagnosis and treatment of diseases to its use in energy generation and nuclear weapons. However, if radioactive substances are not stored or used properly, they can potentially cause significant ... |
how do elevator logistics work? that is: what happens to an elevator car after it deposits somebody at their floor? does it stay at floor n until called to another, or immediately go back down to floor 1? | That totally depends on the traffic pattern and the predictability of the traffic and the smartness in the system.
For example, in the morning most traffic is from the bottom to somewhere higher. So when the carriage is empty it might go down to the bottom so that when somebody comes they don't have to wait.
Also large buildings have different sets of lifts for the higher and lower floors, so the people in the higher floors skip the first say 20 floors before it starts offloading them at floor 21 and higher.
| [
"An elevator of this kind uses a vacuum on top of the cab and a valve on the top of the \"shaft\" to move the cab upwards and closes the valve in order to keep the cab at the same level. A diaphragm or a piston is used as a \"brake\", if there's a sudden increase in pressure above the cab. To go down, it opens the ... |
Are the hamburgers you get from traditional fast food chains like McDonald's really THAT terrible for you? | Please everyone, "Super Size Me" and other such documentaries are not considered valid scientific sources. Please refrain from referring to them as such. | [
"The McDonald's fast-food chain sells the Big Mac, one of the world's top selling hamburgers, with an estimated 550 million sold annually in the United States. Other major fast-food chains, including Burger King (also known as Hungry Jack's in Australia), A&W, Culver's, Whataburger, Carl's Jr./Hardee's chain, Wendy... |
Did unconnected societies like the Spanish, Inca, Aztecs, etc. all independently mine and value gold? | Yes - many, many societies, with little or no contact between them, have developed similar reverence and/or senses of value (in the economic sense) for gold. Aside from its shininess and relative rarity, it's also very soft and can be easily hammered into shape without heating it - in fact, some of the earliest examples of worked metal found by archaeologists is in gold. [How Stuff Works](_URL_1_) has a good article on the topic, and [Stuff You Should Know](_URL_0_) recently did a podcast on it, which covers some of the metal's history.
EDIT: I should perhaps point out that neither of these sources are at all scholarly, and like everything How Stuff Works does, it is necessarily oversimplified for a general audience. I would heartily welcome anyone with more expertise to weigh in and give some better sources. | [
"Finally, the Andean civilizations lacked money. Copper axe-monies (also called \"naipes\") and \"Spondylus\" shells functioned as mediums of exchange in some areas, especially coastal Ecuador, but most of the Andes area had economies organized on reciprocity and redistribution rather than money and markets. These ... |
why is mixing stimulants and depressants bad? | Mixing stimulants and depressants isn't inherently bad as long as one is careful with amounts. As they are opposites in terms of their effects on the central nervous system, they tend to cancel each other out.
The main danger lies in excessive intoxication. The stimulant masks the effects of the depressant, causing you to take more of the depressant than you normally would. The stimulant then wears off, allowing the depressant to slow your breathing to a dangerous level.
| [
"In summary, tricyclic antidepressants can act through NMDA antagonism, opioidergic effects, sodium, potassium and calcium channel blocking, through interfering with the reuptake of serotonin and acting as antagonists to SHAM (serotonin, histamine, alpha, muscarinic) receptors. Thus their dangerous side effect pro... |
Mechanical traps in ancient temples: did they exist? | There's always room for discussion, but perhaps the section [Were/are there actually tombs filled with deathtraps?](_URL_0_) from our FAQ will answer your inquiry. | [
"Builders of ancient Egyptian pyramids used secret passages and booby traps to protect the burial chambers from tomb robbers. In some cases, a secret door to a burial chamber was hidden behind a statue.\n",
"In ancient Egypt, two priests deposit an ornate box inside a temple, locking the doors behind them. After ... |
Why are oxidized compounds typically in a lower energy state? | Oxygen is a high energy unstable molecule. When it forms bonds with other elements energy is given off. Note So CH4 goes to CO2 + 2H2O. 4 stable C-H bonds + 2 moderately stable O-O bonds turn into 2 very stable C=O bonds + 4 stable H-O bonds - net win. | [
"For transition metals, oxidative reaction results in the decrease in the d to a configuration with fewer electrons, often 2e fewer. Oxidative addition is favored for metals that are (i) basic and/or (ii) easily oxidized. Metals with a relatively low oxidation state often satisfy one of these requirements, but even... |
if bleach is meant to keep clothes white, why does it stain dark clothes randomly instead of altering the entire garment to a lighter shade? | Bleach works by breaking certain chemical bonds.
When these bonds are present, you can see your stains. After you break them, the stains end up only reflecting a wavelength you can't see.
Bleach doesn't eliminate stains, it makes them invisible.
This ends up messing with the dyes in your clothes. It won't make all the dye "invisible" like with a stain but since the bonds are broken and won't spontaneously reform, you end up ruining your clothes. | [
"Bleaches attack the chromophores, the part of a molecule which absorbs light and causes fabrics to have different colors. An oxidizing bleach works by breaking the chemical bonds that make up the chromophore. This changes the molecule into a different substance that either does not contain a chromophore, or contai... |
Battle of Cannae research help | Reading Adrian Goldsworthy's *Cannae* is your best bet imo. | [
"The Battle of Cannae () was a major battle of the Second Punic War that took place on 2 August 216 BC in Apulia, in southeast Italy. The army of Carthage, under Hannibal, surrounded and decisively defeated a larger army of the Roman Republic under the consuls Lucius Aemilius Paullus and Gaius Terentius Varro. It i... |
Why do "Y" chromosomes only have 3 chromatids? | They don't. When replicated, they have two chromatids (and four branches) just like every other chromosome in your cells. Because two of the branches are very short, they can lie next to each other, creating the appearance of a Y under a microscope. However this is a coincidence! The name "Y" was chosen because it follows X, which was originally thought to be the sex-determining chromosome.
From [Wikipedia](_URL_0_):
> The Y chromosome was identified as a sex-determining chromosome by Nettie Stevens at Bryn Mawr College in 1905 during a study of the mealworm Tenebrio molitor. Edmund Beecher Wilson independently discovered the same mechanisms the same year. Stevens proposed that chromosomes always existed in pairs and that the Y chromosome was the pair of the X chromosome discovered in 1890 by Hermann Henking. She realized that the previous idea of Clarence Erwin McClung, that the X chromosome determines sex, was wrong and that sex determination is, in fact, due to the presence or absence of the Y chromosome. Stevens named the chromosome "Y" simply to follow on from Henking's "X" alphabetically.
> The idea that the Y chromosome was named after its similarity in appearance to the letter "Y" is mistaken. All chromosomes normally appear as an amorphous blob under the microscope and only take on a well-defined shape during mitosis. This shape is vaguely X-shaped for all chromosomes. It is entirely coincidental that the Y chromosome, during mitosis, has two very short branches which can look merged under the microscope and appear as the descender of a Y-shape. | [
"The idea that the Y chromosome was named after its similarity in appearance to the letter \"Y\" is mistaken. All chromosomes normally appear as an amorphous blob under the microscope and only take on a well-defined shape during mitosis. This shape is vaguely X-shaped for all chromosomes. It is entirely coincidenta... |
What is the significance of finding King Richard III's remains? | More than anything, it's the significance of the archaeological find - essentially the last medieval king of England, killed on a battlefield in one of the most defining moments in English history.
In terms of popular interest and national heritage, it's of enormous significance. Academically, it's interesting to see how his image was distorted in contemporary imagery - Shakespeare's *Richard III*, for example, with the shrivelled hand, in contrast to the 'real thing'. | [
"Richard's corpse was taken to the nearby town of Leicester and buried without pomp. His original tomb monument is believed to have been removed during the English Reformation, and his remains were lost, as they were believed to have been thrown into the River Soar. In 2012, an archaeological excavation was commiss... |
why aren't short answers to eli5 questions allowed? | From the sidebar:
> E is for Explain - merely answering a question is not enough.
That's the entire point of the sub -- not to give an answer, but an explanation. The idea is not just to answer "what", but "why" and "how". | [
"Some in the field of education argue that closed-ended questions are broadly speaking \"bad\" questions. They are questions that are often asked to obtain a specific answer and are therefore good for testing knowledge. It is often argued that open-ended questions (i.e. questions that elicit more than a yes/no answ... |
in a collision, why does it seem like the impaired driver has a higher chance of surviving it than the innocent driver? | They don't. Several studies have shown that drunk drivers are more likely to be injured or killed when involved in an accident than sober ones. It's a pervasive myth that the opposite is true for some reason, and people have even made up "just-so" stories as to why they fare better, such as the notion that a drunk driver is more relaxed.
What's really going on here is probably simple confirmation bias: people have heard that drunk drivers are more likely to survive, and so pay more attention to stories where they do. | [
"A number of factors contribute to the risk of collision, including vehicle design, speed of operation, road design, road environment, and driver skill, impairment due to alcohol or drugs, and behavior, notably distracted driving, speeding and street racing. Worldwide, motor vehicle collisions lead to death and dis... |
I get the magnus effect. But how does this guy get the soccer ball to change direction twice? | If you look closely, you can see the ball has almost no spin. This causes it to move in several different directions while it flies, which is what makes a knuckle ball is so hard to hit in baseball, even though it is a relatively slow pitch. Here is a video on the science behind the knuckle ball: _URL_0_
| [
"One way of explaining the Magnus effect is that - because of the rotation and the fact that air acts as a viscous or \"sticky\" substance on the surface of the ball, a stream of air in the wake of the ball is being ejected upwards. As a reaction to this, the ball is pushed downwards.\n",
"The ball's direction an... |
Do galaxies have clearly defined borders, or do they just kind of bleed into each other? | I guess strictly speaking they don't have "clearly defined borders." It's not like there's some force holding every start within a specific hard boundary. They're just all orbiting the same gravity well, so they hold together-ish, but the edges are fuzzy because a galaxy isn't a single solid thing.
The thing is though that for the most part galaxies are so staggeringly, unfathomably far away from each other that they don't remotely "bleed into each other."
Even in cases where galaxies are "colliding" there's basically zero collisions happening, because even within a galaxy the **vast** overwhelming majority of the space is empty space between stars.
I guess my point is that space is mostly, well, space. | [
"Clusters of galaxies consist of hundreds to thousands of galaxies bound together by gravity. Clusters of galaxies are often dominated by a single giant elliptical galaxy, known as the brightest cluster galaxy, which, over time, tidally destroys its satellite galaxies and adds their mass to its own.\n",
"When two... |
Were Stories Like The Iliad and The Odyssey Still Told in Greece in the Middle Ages? | According to Judith Herrin’s Byzantium and Lost to the West, both epics alongside many other examples of Greek literature was studied and told throughout the Middle Ages. While it mainly concentrated around the educated in Constantinople and Mystras (as the fortunes of the Empire wanes), there was one instance where an educated noble quoted from the Iliad in order to woo a noblewoman. However, since she wasn’t educated, she asked for it to be interpreted. Greek philosophers were often depicted in mosaic form and in the capital were studied by their intellectuals. The Library of Constantinople held many of the classics aside from other books that were later taken West in 1204 during the 4th Crusade.
Another instance comes from the history of Anna Komnena, a notable female noble and scholar, who would’ve learned the classics. As I noted above, a woman being educated, especially a noble woman, would have been the exception rather than the rule in the Roman Empire of the medieval period.
In the Lost City of Byzantium, Mystras is credited as the progenitor of the Paleologan Renaissance, a revival of Hellenistic thought which throughout the decline of the Byzantine Empire, gradually immigrated to Italy, forming schools in each of the city states where philosophy, the arts and other ideas of the Hellenistic world permeated back into Western thought.
As an interesting thought,some intellectuals in the Empire during the Empire’s final years believed in a return to Greco paganism if not reforming the Empire as a Greek state, showing the beginnings of Greco Nationalism at the waning days of the Empire in the 15th century. | [
"Oral tales have been formed into classic literature centuries later so that the historicity of the events is left to uncertainty. The Greek Heroic Age as described in the Iliad is dated to historic events in 1460 to 1103 BC according to the chronology of Saint Jerome.\n",
"During recent years scholars have sugge... |
why is the "world's first ever color x-ray performed on human body" important or interesting when we already have mri? | Can you link to the article you're referencing? | [
"Ultrasound is the main diagnostic imaging tool on ISS and for the foreseeable future missions. X-rays and CT scans involve radiation which is unacceptable in the space environment. Though MRI uses magnetics to create images, it is too large at present to consider as a viable option. Ultrasound, which uses sound wa... |
how are curse words bleeped out on live television broadcasts? | There is a delay - it's not really live. Every since the Janet Jackson nip slip there has been a 7 second delay (at least) that allows for bleeping or censoring in _almost_ realtime. | [
"The script allowed the prisoners to swear without offending viewers by using the word \"naff\" in place of ruder words (\"Naff off!\", \"Darn your own naffing socks\", \"Doing next to naff all\"), thereby popularising a word that had been virtually unknown and the first recorded use of which was in 1966. Ronnie Ba... |
How much electricity would be created per day if every Walmart and Home Depot in America covered their roof with solar panels? | Some quick googling tells me there are roughly 9000 Wal-mart stores, with an average club size of 134,000 sq. ft. Assuming an average solar panel output of 10 W/sq. ft. and an average day of 12 hours, I get a result of 144,720,000 kW*Hrs. | [
"During the store's first year, Schaeffer bought 100 9-Watt solar panels for $600 each and sold them for $900 each to people interested in getting their electricity from a source other than an electric utility. These sales made Real Goods the first company to sell a solar panel commercially in the United States.\n"... |
how do ebay auctions benefit buyers/sellers as opposed to buyitnow? | You can get a better deal buying with an auction but it takes like 10 tries. I've won GTA V for like $12 and COD BOII for like $8, but then sometimes the seller sends you some bullshit about "sorry, I lost the game, my bad" and you have to start all over. When I sell a game on eBay I usually do buy it now unless it's an old cult classic. My Shadow the hedgehog for old xbox started a bidding war and it went for like $20. | [
"The auctioneer offers his goods, commodities or services on an auction side on the internet. Interested parties can submit their bid for the product to be auctioned in certain specified periods. The auction is transparent, all interested parties are allowed to participate the auction in a timely manner.\n",
"Dur... |
why are phones so much more expensive than other mobile technology??? | Miniaturization. It's the same reason laptops are more expensive than desktops. It's pricier to make things smaller.
To a lesser extent, Steve Jobs set the price of the first iPhone based almost purely on his gut feel of what people would pay. It seems to have stuck | [
"Mobile phones are spreading because the cost of mobile technology deployment is dropping and people are, on average, getting wealthier in low- and middle-income nations. Vendors, such as Nokia, are developing cheaper infrastructure technologies (CDMA) and cheaper phones (sub $50–100, such as Sun's Java phone). Non... |
Can you detect many chemicals, mixed together, below their odor detection level? | There are many possibilities.
If the mixed chemicals remain completely distinct and do not interact or change in any way within the mixture, they will all remain undetectable.
If the chemicals DO react with each other, than they could produce new compounds with more easily detectable traits. They could also produce new compounds which are less detectable.
The mixture of the chemicals could also influence temperature, volatility, physical state... all of which could potentially influence detection. In other words, if you mix the chemicals and the mixture becomes heated/volatile, the concentration that reaches your nose could increase to a detectable level. | [
"The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. The thresholds of a chemical compound is determined in part by its shape, polarity, partial charges and molecular mass. The olfactory mechanisms responsible for a compound's differen... |
The use of theory within history essays | It's a bit difficult to do this without reference to a specific theory or without further specification so this is going to be very general. I also don't know how far you cast your question so I am going to start with basics and I hope you can forgive me if you know most of this already.
Basically, in most cases a work in history whether it is an essay or a longer work is structured around a central question, meaning the thing you want to find out. Designing such a research question is an essential step in the work of a historian because it already is a lot of work. It's based on work within the historiography, meaning it is designed to find out something we don't know yet ideally (this is not such a strict requirement in the case of essays though it can be) and often also on the source material you know is available (finding that out is also a piece of work mostly). This question can take the form of f.ex. "What were the influential factors for the escalation of violence by German troops in the Soviet Union?" or "What role did Protestant teachings play in the German peasant wars?" – basically something you want to know.
To answer your question you need a methodology, meaning a way to come from your question to an answer with your source material. Say, for instance, you decide to ask about the influential factors for the escalation of violence by German troops in the Soviet Union you can go about answering that question in various ways: You can, say, focus on analyzing propaganda aimed at the troops and the images of the enemy it presents. Or you can, for example, focus more strongly on the situational circumstances of individual units and see if there is a connection between the escalation of violence and the experience of concrete or imagined imminent danger. Both of these are viable but they necessitate different methodological approaches: To focus on propaganda and the images of the enemy would work with a discourse analysis, concretely, to analyze what is said and thought on a social level about real or imagined enemies. To go the situational route would, on the other hand, need a methodology tailored to explaining what makes people act in a certain way such as the sociological theories of Erving Goffman.
Additionally, historical work necessitates to formulate a (hypo)thesis, meaning a potential answer to your research question you set out to prove with your methodology. Staying with the same example, you hypothesis can be that it was the general Antisemitism and anti-Communism of Nazi German society that lead to the escalation of violence in the USSR or you can formulate the thesis that it was the concrete experience of Partisan warfare that weighed more heavily as a factor in said escalation.
So, to quickly recap: A historical work is based on a research question, formulates a (hypo)thesis as to the answer of said question and has a methodology it utilizes in answering said question and (dis)proving the (hypo)thesis. Every one of these steps can be (and mostly is) based on theory. A theory delivers you a priori and basic assumptions about how the world/society/individuals work. That's what makes it a theory, as a system of general thought about society and the world. If you, say, embrace the theory of classical Marxism, you embrace the thinking that culture and social ideology is mostly based on the economic base and material conditions. If you do so, you will naturally ask different questions about the past, formulate different (hypo)theses about the questions, and use a different methodology than, for instance, someone who embrace Foucault and discourse theory. So already what questions you ask and what theses you formulate about potential answers is something influenced by theory.
However, where theory is most important is regarding the methodology. Methodology is not exactly theory but most methodology is based on theory because theory delivers the tools of methodology. To discuss this once again with the above example: You want to show that the German escalation of violence in the USSR is based upon the experience of Partisan warfare. How can you show that? You need, for example, a methodology that can go into detail about how people act. Such a methodology will be based upon one or more theories that lay out in general how people come to act in general. You could go with the above mentioned Erwing Goffman: Goffman says humans act because of three conceptual frames, meaning ways to organize experience about the world: A social frame, a situational frame, and individual frame. A social frame is how a society culturally determines the organization or experience; a situational frame is how we can perceive an individual to perceive certain situations (a threat etc.); the individual frame is based on how an individual's previous experience and upbringing determines how they organize information (whether they were raised Catholic or Protestant, whether they were veterans etc. etc.).
Based on such a theory, you can formulate a methodology to answer such a question. You can, for instance, look at sources from selected examples of individual soldiers and try to determine thier individual frame of reference to learn something larger about the dynamic of escalation. Or you can focus on what the Wehrmacht taught about situations in order to arrive at the situational frame of reference. Or, should you instead focus more on the propaganda and go the other route, you'd need, say, a discourse analysis that takes what words and concepts are frequently invoked in propaganda in order to determine what the social disocurse about Partisans, Jews etc. was.
So, in short, theory is indispensable to formulate methodology but also influences question and thesis. In a university essay context, I'd wager that the part about methodology is the most important one and hence this is where I'd see theory as most important for you. | [
"History and Theory is a quarterly peer-reviewed academic journal published by Wiley-Blackwell on behalf of Wesleyan University. The journal was established in 1960 and its editor-in-chief is Ethan Kleinberg (Wesleyan University). The journal focuses on the nature of history, including the philosophy of history, hi... |
why do we 'need' money/funding to do things like cure cancer or find alternative fuel sources or explore space? | So, join the effort to cure cancer. Dedicate the next 30 years of your life to it. You won't get any paychecks.
What? Not interested? Well, neither is anybody else. | [
"The goal of the Fund is to provide support to the brightest individual scientists pursuing careers in cancer research while promoting and emphasizing the value and contribution of the individual in keeping with the spirit of the conception of the Fund.\n",
"The research that is conducted by national space explor... |
what are securities in a financial sense? | A security is effectively a legally-enforceable promise which can be traded, sold, or otherwise exchanged for financial gain. Imagine if I write a legally enforceable promise on a piece of paper saying "I will, on December 24, 2018, transfer my car to the bearer of this note." If a court would enforce this promise, the note would have value, and people might be interested in trading this note. If I take good care of the car, the note might stay at its value. If I was to crash the car, then the promise would now only give the note-bearer the right to take a wrecked car, meaning that people would value the note less and its value would go down. If I was to make improvements to the car, on the other hand, the note-bearer would have the right to take the improved car, and the value would probably go up.
A stock is a legally-enforceable right to own a percentage of a company. A Treasury bond is a legally-enforceable promise by the US government to pay the bearer of the bond money (Which the government sells for money. Government sells the bond, gets money now, and in exchange has sold someone the right to collect money on the bond over a fixed time period). | [
"A financial asset is a non-physical asset whose value is derived from a contractual claim, such as bank deposits, bonds, and stocks. Financial assets are usually more liquid than other tangible assets, such as commodities or real estate, and may be traded on financial markets.\n",
"Investment Securities are secu... |
When did brides start to dress in white for their mariage? | The fashion is much later than that, it was started by Queen Victoria, who wore a white wedding dress because it was her favorite color, then fashionistas copied her and it's just stuck around. It was an unusual choice at the time, bright, happy colors were more popular, but anything except black was acceptable. The color had no symbolism at the time, the whole white= virginity thing came later. [Here's a little article.](_URL_0_) | [
"Though Mary, Queen of Scots, wore a white wedding gown in 1559 when she married her first husband, Francis Dauphin of France, the tradition of a white wedding dress is commonly credited to Queen Victoria's choice to wear a white court dress at her wedding to Prince Albert in 1840. Debutantes had long been required... |
if multiple countries economic systems collapse... | What about the people who don't produce food? They're all going to starve while you get the economy started back up. | [
"One of the main reasons for the development of an economic crisis is when a world power country enters in the crisis, eventually all countries get affected. Basically a crisis leads a country to debt and economic stagnation. And it’s ultimately influenced by all kinds of factors such as culture, climate, previous ... |
why has california not legalized pot beyond medicinal use? | Some of the most well funded anti-legalization lobbies in the state are sponsored by the legal dispensaries and co-ops. They would hate to have inexpensive, high-quality, locally and responsibly sourced cannabis flood the market and ruin their racket. | [
"On November 2, 2010, the state of California voted on Proposition 19, which entailed legalizing marijuana for personal uses, growing or cultivating it, as well as sale and taxation of it. The Proposition lost by 500,000 votes out of the near 7 million votes cast. \"Californians recognized that legalizing marijuana... |
How much does the earth need to move to/from the sun in order for life to end? | [There are various estimates](_URL_0_) but we're probably closer to the "too hot" edge than the "too cold" edge. About 5-25% closer to the sun, the greenhouse effect is strong enough to cause much of the oceans to evaporate, which causes a stronger greenhouse effect, and eventually all Earth's surface water is blown off into space. We end up like Venus.
Around 20-100% further out and the greenhouse effect no longer functions properly because CO2 forms clouds that reflect out more heat than they trap. The planet cools and some of the CO2 ends up forming surface ice--along with all the water. We end up sort of like Mars but with more ice.
The sun is gradually warming up over its lifetime, so in about a billion years the habitable zone will move past Earth and the former outcome will happen. | [
"Life on Earth is dependent on the Sun's light and heat in order to survive, but our Sun won't live forever and eventually it will die one day. However, the Sun's death will not happen for billions of years. What if the Sun started aging rapidly at an accelerated rate?\n",
"The Sun will evolve to become a red gia... |
why are the search results when googling an unknown phone number so terrible? | I actually think google intentionally obfuscates results. Back in the day, googling phone numbers worked *awesome*. It was one of the first "best answer" things at the top of the page.
Quite suddenly it stopped working. | [
"Some directory enquiries services stand accused of inappropriate methods of promoting their services, effectively scamming people into calling. Various unallocated geographic and non-geographic numbers play an announcement directing callers to call a particular directory enquiries number for help. People may hear ... |
if christian churches are non-profit / not-for-profit, how do full-time pastors/reverends earn a salary? | Paying your employees isn't profit. The pastor/reverend is an employee of the church.
I can answer the question in one sentence so technically it doesn't belong here.
Also, all churches/temples/mosques/synagogues are like this. Christian churches arent getting special treatment. Loaded question much? | [
"The church has no salaried ministry; however, some general authorities receive stipends from the church, as needed, using income from church-owned investments. All local and area authorities are unpaid and continue in their normal occupations while serving in leadership positions.\n",
"The LDS Church pays to mai... |
What did Gorbachev envision as the ultimate endgame of perestroika? | This is a very complicated question, and one that is very much open for interpretation, but I'll take a stab at it and hopefully fill in some holes.
When Gorbachev came to power, the USSR was in a dire decline. The economy was stagnant, the leadership corrupt, and public support at a low. There was a very credible fear that the experiment of communism would result in a failure. Gorbachev, a scholar of both the West and traditional Bolshevism came to the helm at the apex of this crisis. Gorbachev's answers to Russia's problems were two policies: perestroika ("restructuring") and glasnost ("openness"). To put them in basic terms, their aim was to reinvigorate the economy by slightly relaxing the reigns of government control in a way that would be viewed much like successful New Economic Plan that improved the economy greatly after the Russian Revolution (and its detrimental war-time communism).
The problem with this image of a newly-invigorated yet still traditionally Bolshevik Russia was that perestroika and glasnost called for more collaboration with the West, and more capitalist policies (which, naturally, the aforementioned corrupt leadership didn't like). For example, he opened the door to a lot of western companies, such as fast food chains, and tried to root out corruption.
The public's view of Gorbachev's policies was split over perestroika and glasnost.. which is very accurately and briefly portrayed in this Russian Pizza Hut commercial: _URL_0_
So what were Gorbachev's aims? In short, to maintain a communist tradition in Russia by modifying it for the times. He wanted to ensure that communism remained a viable option for Russia (and others!) in the 21st century. Perestroika was NOT a last ditch attempt to save the USSR. In fact, many economists argue that it was a well formulated policy, but it was too little too late.
| [
"What END was probably best known for, however, was its work with dissidents in the Soviet Union and its east-central European satellite states. Although the END Appeal had won some support from dissidents in the Soviet bloc at its launch, most were hesitant about the western peace movements, which they felt were p... |
Did two-headed axes historically exist and were used? | They did but not in the way you think.
The double headed axe comes from a Minoan object, the Labrys, and as best we can tell it was a religious or symbolic item. Employing a double headed axe on a battle field isn't the best idea, because there is more weight and therefore if you miss your stroke and fail to kill the enemy you are tugged in whatever direction the axe head is going, this is the same reason why war hammers aren't giant (if you want to see for yourself pick up a sledge hammer and give it a swing).
Where double headed axes are actually used is generally in the logging industry. If you take a look at war axes you'll notice that the neck of the axe is relatively thin as throwing axes were sometimes meant to break, while logging axes are thicker and mean to be used for a very long time.
I'm in school now so I can't give you any sources off the top of my head, but I enjoy military history so as soon as I get home Friday afternoon I can consult my library and give you some sources. I hope this helped | [
"In the 14th century, the use of axes is increasingly noted by Froissart in his Chronicle, with King John II using one at the Battle of Poitiers in 1356 and Sir James Douglas at the Battle of Otterburn in 1388. Bretons were apparently noted axe users, with Bertrand du Guesclin and Olivier de Clisson both wielding a... |
What is left after DNA degrades? | Lots of things happen to DNA as it degrades. The DNA shears (the two strands of the double helix come apart, and the resulting single strands and double strands also get chopped up by mechanical shearing), mutations accrue over time where certain bases are replaced by others and nucleic acids dissolve/disassociate in the unfavorable conditions. This degradation occurs as an exponential decay. Interestingly, certain mutations are more common than others over time (C to T for example). If you imagine the words in this explanation as the original DNA sequence, not only do the words get jumbled, but various letters change over time as well. | [
"Breaks in DNA due to ionizing radiation can be repaired. New DNA synthesis by DNA polymerases is one of the ways radiation induced DNA damage can be repaired. However, DNA polymerases do not insert methylated bases which leads to a decrease in methylation of the newly synthesized strand. Reactive oxygen species al... |
Tiny patches of gray hair started growing on my head; why? | The fact they show up in the same spot all the time is common. In your skin at the root of your hair, cells that produce your hair remain embedded. These cells usually never die (unless you go bald, are burned there, or electrocute them with those tweezers).
These cells also don't usually change their color. However, once they go white, they never go back.
What they DO do is they can cycle through a "growing" and a "resting" phase. When these root cells rest, your hair falls out (because nothing's really holding them in) and your white hair seems gone. However, sometime later that single hair root may start again.
What science does not yet know:
- We don't know what specifically makes hair root cells go white. True, stress and age (which is an accumulation of stress) can do it - that's why you might see a whole head of gray hair. But your single patch, that's hard to know.
- We don't know what makes these hair root cells to cycle from growing and resting. | [
"In some cases, gray hair may be caused by thyroid deficiencies, Waardenburg syndrome or a vitamin B deficiency. At some point in the human life cycle, cells that are located in the base of the hair's follicles slow, and eventually stop producing pigment. Piebaldism is a rare autosomal dominant disorder of melanocy... |
why would a ball stop bouncing on the ground | A hypothetical perfectly elastic collision between a ball and the ground in an atmosphere-free environment could create a situation where the ball would essentially continue to bounce forever, yes. It would be simple harmonic motion pretty much the same as an orbit.
What is ultimately causing the ball to bounce less is kinetic energy being converted into heat via air resistance and being lost to inelasticity in the material. Basically, the eternally bouncing ball is the perfect situation that we can never quite get to as long as we are dealing with real matter in the real world. | [
"Nevertheless, bouncing an oval-shaped ball is still a volatile skill. Even top level players will occasionally lose the ball while bouncing it, by accidentally bouncing the ball on its point, only to see it quickly skid away from him or her.\n",
"A \"bouncing ball tribometer\" consists of a ball which is impacte... |
How do you measure carbon dioxide in old ice? | The ice [contains tiny air bubbles](_URL_0_) where samples of atmosphere at the time of freezing are trapped. This gas is extracted and usually analysed with gas chromatography. | [
"The most direct method for measuring atmospheric carbon dioxide concentrations for periods before instrumental sampling is to measure bubbles of air (fluid or gas inclusions) trapped in the Antarctic or Greenland ice sheets. The most widely accepted of such studies come from a variety of Antarctic cores and indica... |
squareroot of a number? | I'm going to recycle the answer I gave in [this thread](_URL_0_) and add that, as /u/JOLLY-RANCHER-STORY points out, that the Babylonian method can be quickly explained as:
To find the square root of S, guess any x, then update your next guess to be the average of x and S/x; one of those is less than the square root of S, the other is larger, so the real answer must be in between. Further, the new guess will be closer than the old guess, so the process converges to the true answer.
-----------------------------
There are many ways to calculate a square root, dating back as far as the Babylonians. As far as how modern calculators do it (i.e. which method they implement), that is maybe more of an engineering question, but I can run down a couple of the methods.
**The 'Babylonian' method**
Given a number *S*, finding it's square root is the same as finding solutions of *x^2 - S = 0*. Take an initial guess *x_1*. Assuming our first guess isn't correct, there will be some error *e*, i.e. *S = (x_1 + e)^2*. We can expand this expression:
*S = x_1^2 + 2 x_1 e + e^2* and solve for *e*:
*e = [S - x^2 ] / [2x + e]*
We assume the error is small compared to x, and so we have
*e ~ [S - x^2 ] / 2x*
Now, to get a better guess, we take
*x_2 = x_1 + e = x_1 + [S - x_1^2 ] / 2 x_1 = [S + x_1^2 ] / 2 x_1*
and repeat the process over and over, i.e.
*x_{n+1} = [S + x_n^2 ] / 2 x_n*
until reaching the desired accuracy. This is a special case of Newton's method, which I'll come back to later.
**World-famous Taylor Series**
In Calculus courses, students learn another way to (sort of) do this with Taylor series. In particular, it is possible to approximate the square root of x via polynomials. For instance, the square root of a number x between 0 and 2 can be approximated by
1 + (x-1) / 2 - (x-1)^2 / 8 + (x-1)^3 / 16 - 5(x-1)^4 / 128
This method isn't that practical though - given a particular number you want to find the square root of, you'd have to find a series that worked (e.g., to find the square root of 15, my formula above won't work), and it won't converge that fast either (in terms of amount of work vs. accuracy).
**Newton's method**
Another thing students learn about in calculus (and then forget) is Newton's method. You need to understand how to take a derivative of something, but barring that, it's straightforward. Again, we phrase the problem as wanting to find the value of *x* so that *x^2 - S = f(x) = 0*. Then Newton's method says that if we start with an initial guess of *x_0*, and define iteratively
x_{n+1} = x_n - f(x_n) / f ' (x_n)
then (under some other mild hypotheses), this process will converge to the correct result.
For our square root problem, this is the same as the Babylonian method, as f ' (x) = 2x in this case. But it can be used to solve more general types of problems, for instance if we now want to solve your **cube** root problem, we choose the function to be f(x) = x^3 - S, and go from there. In this case, f ' (x) = 3 x^2, and so the Newton's method iteration is
x_{n+1} = x_n - [x_n^3 - S] / [3 x_n^2 ] | [
"It is a square number, being 5 = 5 × 5. It is one of two two-digit numbers whose square and higher powers of the number also ends in the same last two digits, e.g. 25 = 625, the other is 76. It is the smallest square that is also a sum of two (non-zero) squares: 25 = 3 + 4. Hence it often appears in illustrations ... |
How is feline leukemia contagious but human leukemia isnt? | It sounds like you're thinking of feline leukemia virus, which is a virus that causes leukemia. As a general rule, cancers including leukemias are not contagious, but if they are caused by a contagious virus, cases of cancer will spread. This is analogous to HPV in humans, which is sexually transmitted and causes cervical cancer. Someone with just cervical cancer won't be able to pass it to someone else, but if their cervical cancer is caused by HPV, they can pass on the HPV, which can lead to cancer in new hosts. | [
"The signs and symptoms of infection with feline leukemia virus are quite varied and include loss of appetite, poor coat condition, anisocoria (uneven pupils), infections of the skin, bladder, and respiratory tract, oral disease, seizures, lymphadenopathy (swollen lymph nodes), skin lesions, fatigue, fever, weight ... |
Why did Germany continue its aggressive foreign policy after Britain joined the Triple Entente? | Germany was in the Triple Alliance to counter it with Austria-Hungary and Italy. Germany was ambitiously trying to be a colonial power and needed to counter British control of world trade and sea lanes. With the second reich, Germany now being under one government merged by Otto von Bismark, they had the potential to be the greatest nation in Europe. A united Germany with its resources and industrial might was a contender to out shine the Britain, France, Russia.
Britain's foreign policy for centuries was always to switch sides and align themselves with whoever kept a divided Germany and divided main land continent. Germany knew this, and knew they had the potential to out grow Britain, if they could acquire overseas colonies.
Essentially they were a contender.
Keep in mind also that it was very unclear which side the US would align themselves with, in the event or War. Germany knew this. It could've just as easily been a scenario in world war one, where the US would align themselves with Germany. Millions of Italians and Irish and Germans in the US. Much hatred to British system of government. While World War I raged in Europe, a German U-boat commander in 1918 met the mayor of Baltimore and was given a parade through the streets of Baltimore, before refuelling and heading north to try and torpedo British and Canadian merchant ships.
| [
"The alignment between Britain, France and Russia became known as the Triple Entente. Therefore, the Triple Entente was not conceived as a counterweight to the Triple Alliance but as a formula to secure imperial security between these three powers. The impact of the Triple Entente was therefore twofold: to improve ... |
For lithium ion batteries, is it better to keep it fully charged or let it deplete and recharge? | I've done extensive research into batteries. Someone else here said
> In effect, it doesn't really matter what you do with your battery, leave it on the charger as long as you like.
While I respect the point he's trying to make, that isn't strictly true. It depends on the sophistication of the charging controller. Some of the better designed smart chargers actually cycle your battery gently (which is good for the battery), but others are kind of dumb and just let them "trickle charge" (this is when the charger just gives it enough juice to overcome the battery's internal discharging).
Trickle charge is very useful when you're leaving a battery in the charger for a little past its charging time; it'll keep the battery topped off in a responsible manner. However, it's not good for the long-term, because the battery needs to be cycled to keep its chemistry active.
Since you don't know how smart the device charging your battery is, **it's best practice to allow the battery to discharge a little bit every day**. If you're talking about a laptop, unplug it for a bit and let it dip down to 70% or 50%, even if you don't "need" to use the battery. This will keep your battery alive as long as possible. Leaving the laptop in charge mode all the time will [usually; again, this depends on the design of the charging circuit] kill the battery faster.
**Edit for clarity:** it's strictly *best* to leave your Li-ion battery at a constant cell voltage of 3.9V. My point is that many Li-ion chargers are "dumb" and will leave your battery close to its max cell voltage of 4.2V. Since you don't know whether your charger is smart or dumb, allowing gentle daily charge cycling will keep your cell in the 3.8 - 4.0V range, which is better than leaving it permanently near 4.2V. Too much cycling too often will kill your battery faster, and no cycling with a constant cell voltage of 4.2V will also kill your battery. I advocate gentle & shallow cycling for the strict purpose of keeping your cell voltage as close to 3.9V as possible while also minimizing the amount of charge entering or leaving the cell. | [
"The lithium-ion batteries are appealing because they have the highest energy density of any rechargeable batteries and can produce a voltage more than three times that of nickel–metal hydride battery cell while simultaneously storing large quantities of electricity as well. The batteries also produce higher output... |
When I hear a sound, what kind of information is sent to my brain? | It is something like the Fourier transform of the sound. The [inner ear](_URL_0_) and in particular the [cochlea](_URL_16_) has a fascinating organization that allows the brain to breakup the incoming signal into its frequency components.
Here's the rough idea: sound waves arrive as air pressure and hit your eardrum, this produces a conversion from air pressure to mechanical energy as the ear drum vibrates causing [three small bones](_URL_10_) in your middle ear to also move / vibrate ("hammer" "anvil" and "stirrup"). These bones act as amplifiers. The stirrup is attached to the [oval window](_URL_6_) on the cochlea which it causes to vibrate. This vibration is converted to pressure waves in the liquid contained in your cochlea. These pressure waves cause the [tectorial membrane](_URL_3_) (a membrane in the middle of the [organ of corti](_URL_15_) which is a part of the cochlea) to move. The tectorial membrane is attached to hair cells (see [here](_URL_17_) which are pulled and relaxed as the membrane moves. These cells have mechanically gated ion channels at their tips that open whenever the cells are pulled (see the top of the picture [here](_URL_8_). In other words, these cells release neurotransmitters after mechanical stimulation. Pretty awesome.
These hair cells are arranged all along the length of the basilar membrane, the center of the cochlea. This membrane does not have a uniform width. The base (where the oval window is), is narrower than the apex. It is also stiffer at the base and more flexible at the apex. This means that as the pressure wave travels through the liquid, both the basilar and tectorial membranes are displaced by different amounts depending on where in the cochlea they are. See [this](_URL_13_) informative diagram. As a result, the base of the membrane is most sensitive to high frequency waves while the apex is most sensitive to low frequency waves. Or, you can think of it as: different parts of the membrane move by different amounts depending on the frequency components of the sound; the hair cells in the parts that move are stimulated and release neurotransmitter; so, depending on which haircells are stimulated, we can know what frequencies were present in the sound.
This organization is preserved all the way to primary auditory cortex (A1), which has a [tonotopic](_URL_9_) organization, meaning that nearby cells in A1 code for adjacent frequencies like [this](_URL_14_).
Edit: here are a few more images that may be helpful:
[middle ear](_URL_2_) (malleus, incus, and stapes are the anatomical names for hammer, anvil, and stirrup respectively).
[a comprehensive picture](_URL_7_) of signal transduction in the ear
[another view of how stereocilia are moved by the basilar membrane](_URL_12_)
[structure of tip-links and ion channels on the stereocilia](_URL_1_) that open when the basilar membrane moves.
[Electron microscope image of hair bundles](_URL_11_)
[development / growth of bundles](_URL_4_)
[Another view of frequency coding](_URL_5_) and [here](_URL_18_) | [
"Much like the McGurk Effect, when listeners were also able to see the words being spoken, they were much more likely to correctly identify the missing phonemes. Like every sense, the brain will use every piece of information it deems important to make a judgement about what it is perceiving. Using the visual cues ... |
Why do some geographically isolated islands produce more biodiversity than others? | There are a lot of factors, such as ease of colonization (distance from mainland, ocean currents), amount of sunlight (latitude), size of the island, age of the island (state of ecological succession), and rainfall. Also, do a search for Island Biogeography, I did and got this _URL_0_
edit: added ocean currents and state of ecological succession | [
"The diversity of species on islands is highly impacted by human activities such as deforestation and introduction of the exotic species. In response, ecologists and managers are directing attention towards conservation and restoration of island species. Because they are simple systems, islands provide an opportuni... |
Why exactly did the gunpowder to cannonball weight ratio in cannons drop by the 18th century? | TL;DR: Improvements in metallurgy, allowing for smaller grain sizes and higher chamber pressures, along with various other improvements that increased the ballistic efficiency of guns and allowed less propellant mass to achieve equal muzzle velocities.
# < Warning: probably a bit physics-heavy >
I can provide some insight in the physics behind cannon barrels and ballistics, to provide some general explanations. I don't know the developments of the period by heart however, so I will add the historical context and overview of relevant developments in the 18th century a bit later when I have more time.
Ideally, the muzzle velocity of a projectile is determined entirely by only 3 variables:
1. Force on projectile (along a section of a barrel)
2. Mass of projectile
3. Barrel length
This is still quite simple, and quite useless. In practice, the force of the expanding gases on the projectile is not constant along the barrel, and it's much easier to work with the **pressure** times the cross-sectional **area** (often expressed as the **bore** of the gun) of the projectile instead. Of course gun barrels and projectiles are not infinitely strong, thus mechanical properties such as **yield** and **ultimate strength** of the projectile and barrel must also be taken into account. The pressure in the barrel is created by a chemical reaction, the speed of which is mostly dependent on the **type of compound** used, the **mass of compound** used, and the **grain size**.
This already leaves us with a whole bunch of key variables that can be changed to get different shapes and types of chemical guns, ranging from the tiniest pistol to mortars with ridiculously short and wide barrels. Summed up the key variables to muzzle velocity are now:
1. Projectile mass
2. Projectile ultimate strength^^1
3. Barrel length
4. Barrel thickness^^2
5. Barrel material yield strength
6. Propellant compound
7. Propellant mass
8. Propellant grain size^^3
9. Bore radius / projectile cross-sectional area
This is a bit more complex as you can see, but with these variables we can accurately model the characteristics of any conventional gun. Now onto applying it to actual early artillery!
Early cannons were very limited in range^^4, minimum mass, minimum bore size *and* propellant, due to the low-quality cannon material. Cannons came in many, many, *many* shapes and sizes, but commonly were made out of cast iron or cast bronze. Being in its infancy, the quality of the cast guns was relatively terrible and they contained many faults that compromised integrity. This meant *pressures inside the cannon had to be kept low* to prevent the cannon from turning into a giant bomb. Keeping the pressures low means less force on a projectile and correspondingly less velocity, which can only be compensated for by increasing barrel length, or increasing bore size. And that's exactly what was commonly done. The bombard for example had proportions that [look utterly ridiculous to us](_URL_0_) with a very wide bore and very short barrels. The wide bore ensures however, that a projectile can be accelerated fast even with a relatively low pressure^^5. Not unimportant either, is that a short barrel reduces weight considerably, which allows for a *thicker* barrel, which allows for *higher pressures*. You'll see where this is going: There are a ton of trade-offs to make, and everything is tied together. You change X, then Y and Z change as well.
*So what changed around the 17th century that allowed for the use of less propellant mass?*
The **'ballistic efficiency'** increased, likely due to better metallurgy and other continuous developments. Ballistic (BE) efficiency is defined as:
Ballistic efficiency (BE) = Kinetic Energy of projectile / Energy of propellant
This is a percentage, often between 1-50%.
A lot of gunpowder is being burned in a cannon, but not all of the energy that is released is being used to accelerate the projectile. Early cannons had terrible BE, which meant a lot of gunpowder had to be used to achieve the desired results. The most important reasons for this were the aforementioned low chamber pressure, the short barrels, and something known as 'windage' - the gap between the projectile and the barrel of the gun. Lacking precise manufacturing tools, the windage of old cannons was very large and reduced the already low BE even more. Cannons were continuously being improved over this period however. Metal casting techniques, as well as other aspects of metallurgy were all being developed and resulted in cannons that could support higher pressures at the same mass. Stronger materials also allowed for the use of finer grained propellant. Gunpowder with a small grain size burns much faster, which increase acceleration of the projectile for the same amount of propellant mass, and thus increases BE (only up to a certain point though). Improvements in the precision of barrel and projectile manufacturing could reduce windage, which also increases BE. Lastly, a longer barrel will always improve BE, and thus we can predict that this *may* have been the case.
I'm out of time right now, and I think this will be enough of a general physics answer, but I'll see to comparing some specific examples of the period later on and checking which variables changed the most. It's unlikely to be just one though; more likely the *general* design and manufacturing of artillery improved, involving several variables.
**Addendum**:
1. The reason this needs to be taken in account is that the projectile can and will be destroyed if the pressure exceeds its ultimate strength. Barring a few exceptions, having a projectile break up is bad. Stone projectiles could be used in early cannons for similar reasons. Chamber pressures and projectile acceleration were low, which meant the stone projectiles stayed intact despite being exceedingly brittle compared to even low quality iron. As chamber pressures increased, stone projectiles could no longer sustain the stresses and disappeared, as cast iron projectiles eventually did as well.
2. The exact pressure a barrel can handle is of course a more complicated result of its geometry and composition. For understanding this, it is however enough to see that increasing the chamber pressure of a gun requires either a *thicker* barrel or a *stronger* material. The former of which increase weight, which is a serious consideration, and the latter of which requires an improvement in metallurgy.
3. Grain size is the size of individual grains of gunpowder. The technique for creating these grains was in Europe discovered centuries before the 1600, and it was thus widely known that changing the grain size also changed the burn rate inside the cannon. Cannons typically used (and still use) very large grains compared to rifles, because a rapid-burning propellant would result in destruction of such a large gun. Smaller grain size equals higher pressure, even without increasing the propellant mass.
4. Range is a function of muzzle velocity and the ballistic coefficient of a projectile. In this period, the aerodynamics of cannon balls were typically 'horrible' and not subject to much change. In addition to muzzle velocities being low compared to contemporary artillery, I will use range as a synonym to muzzle velocity here, consciously neglecting drag effects and such.
5. Only up to a certain point. An oversized bore will require more propellant in turn, to produce enough gases to fill the larger volume, hence there is an optimum bore size. There also more general downsides to having a large bore, most notably the ballistic coefficient of your projectile goes down (e.g. it's less aerodynamic for the same mass), so range can be reduced ^(not too relevant to the guns of the era though). Different sizes of projectiles also have vastly different characteristics on hitting their target, and having a projectile that is too wide and light may result in a dramatic lack of penetrating power ^(also not very relevant to the era). | [
"By the 16th century, cannon were made in a great variety of lengths and bore diameters, but the general rule was that the longer the barrel, the longer the range. Some cannon made during this time had barrels exceeding in length, and could weigh up to . Consequently, large amounts of gunpowder were needed to allow... |
people getting red light camera/speed camera tickets | Depending on your jurisdiction they can just say "Your vehicle, your responsibility. Don't lend it to a speeder next time." | [
"BULLET::::- Sponsored legislation to ban the practice of paying private speed camera contractors based on the number of tickets issued, and require speed camera citation images to contain sufficient information to allow ticket recipients to identify or prove speed measurement errors/a\n",
"Studies have shown tha... |
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