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Rational floating point computations | More accurate? Not necessarily. A floating point number is usually stored in memory using 32 bits. Integers are often stored using 16 bits. So if you take two integers, you still have only 32 bits available. You can only store so much information within 32 bits, no matter how you write it down.
Of course, you don't have to use the built in data types. People have been writing integer types that can be arbitrarily long (as long as you have memory available). Of course this slows down the computation in general. There are even implementations of rational numbers out there. They still can't store irrational numbers though. And then there are things like Mathematica, which can do symbolic computations, which of course includes rational numbers. Again, in general this is much slower than using machine precision. But these days you might not even notice it unless you do some heavy number crunching. | [
"A floating-point data type is a compromise between the flexibility of a general rational number data type and the speed of fixed-point arithmetic. It uses some of the bits in the data type to specify a power of two for the denominator. See IEEE Standard for Floating-Point Arithmetic.\n",
"In computing, floating-... |
How is the CMB be the most distant thing we can see when there is a cosmic horizon? | The CMB we saw a billion years ago (well... would have seen) was emitted by matter closer to us. In a billion years we'll see the radiation from matter so far away that we can't see its radiation yet. At the same time we can follow what happened to the matter later that emitted the CMB we see today.
The matter that emitted the CMB we see today was about 42 million light years away from us at the time of emission. If you do the same calculation for other times then you get a sphere that expands over time. Very early in the universe this radius increased by the speed of light, now it increases by 1/1100 the speed of light (corresponding to the redshift of the CMB since its emission). If you wait long enough this radius will increase to 55 million light years or so. Didn't calculate it precisely. Anyway: It will approach a finite value. We'll never see light from matter more distant than that. | [
"The Cosmic Microwave Background (CMB) radiation signature presents a direct large-scale view of the universe that can be used to identify whether our position or movement has any particular significance. There has been much publicity about analysis of results from the Wilkinson Microwave Anisotropy Probe (WMAP) an... |
do i have to charge my new phone battery to 100%? | short answer: no, you don't have to charge a new phone battery to 100% before use. that's a guideline meant for nickel-based batteries, which do need a full charge before use. the lithium batteries used in today's phones don't need to be fully charged, and in fact, a partial charge is preferable. | [
"Apple Inc. clarifies that a charge cycle means using all the battery's capacity, but not necessarily by discharging it from 100% to 0%: \"You complete one charge cycle when you’ve used (discharged) an amount that equals 100% of your battery’s capacity — but not necessarily all from one charge. For instance, you mi... |
Is it possible to have a Pi amount of some object, or would it be infinite? | Start your car. Accelerate from 0 kph to 20 kph. Somewhere along the way you'll be going pi kph. | [
"Pi certainly seems to behave this way. In the first six billion decimal places of pi, each of the digits from 0 through 9 shows up about six hundred million times. Yet such results, conceivably accidental, do not prove normality even in base 10, much less normality in other number bases.\n",
"Also, the non-repre... |
with gravity being tied to mass, if you were in the exact center of an earth sized object in a protected sphere, would you be weightless or experience intense pressure? | Both.
If you're in the center of a uniform hollow shell - which ultimately this is, although the walls of it are very thick, you will be weightless, because the gravity in any given direction will be cancelled out by all the other directions.
However, the weight of the rest of the planet is still bearing down on your protected sphere, so, um, check for cracks. | [
"The fact that many large celestial objects are approximately spheres makes it easier to calculate their surface gravity. The gravitational force outside a spherically symmetric body is the same as if its entire mass were concentrated in the center, as was established by Sir Isaac Newton. Therefore, the surface gra... |
how do rivers flow continuously? | The water in a river comes from many different sources. Let's try to think of a few. There are springs, where the water bubbles out of the ground. There is rain, where the water precipitates, or falls from the sky. There is the melting of glaciers or snow cover. The water also seeps out of wet ground, and the water we pump out of the ground for use in our homes and businesses probably gets treated and then put back into the ecosystem, where it flows into rivers.
The watershed, or area in which the water will flow to a particular body of water, is quite large for most rivers. All of these sources combine over that large area, to form the river. Rivers naturally rise and fall over time, as the amount of water flowing in changes with seasons and weather. | [
"A river is a natural watercourse, usually freshwater, flowing toward an ocean, a lake, a sea or another river. A few rivers simply flow into the ground and dry up completely before reaching another body of water. \n",
"The water in a river is usually in a channel, made up of a stream bed between banks. In larger... |
could we build nuclear power plants underground? | Must look at the tectonics of the potential site. Unstable tectonics could lead to a disaster | [
"Another project was the world's first light water reactor. With its principles of neutron moderation and fuel cooling by ordinary water, it is the direct ancestor of most modern nuclear power stations. The US Military funded much of its development, for nuclear-powered submarines and ships of the US Navy.\n",
"O... |
Are our pinky and ring fingers mechanically linked? | The tendons that go to these fingers are attached to the same muscle (FDS, FDP). With the tendons being adjacent to one another, it makes it difficult to flex one tendon/finger via muscle contraction while keeping the other tendon/finger completely extended. You are literally contracting one part of the muscle while relaxing the adjacent part pulling the muscle in two different directions. | [
"闘 (Tō): Hands together, index fingers cross each other to touch opposite ring fingers, middle fingers crossed over them. Ring and pinky fingers are straight. Tips of ring fingers pressed together, tips of pinkies pressed together, but both sets of ring and pinky fingers are separated to form a V shape or bird beak... |
the role of queen's guard | It's right there in the name. They are active soldiers who have a duty to guard the royal residences in the UK. They are not for tourists, although a very big tourist attraction, they a trained soldiers who have the authority to kill if needed. Plenty of YouTube videos of them shouting at tourists. | [
"The Queen's Guard is the name given to the contingent of infantry responsible for guarding Buckingham Palace and St James's Palace (including Clarence House) in London. The guard is made up of a company of soldiers from a single regiment, which is split in two, providing a detachment for Buckingham Palace and a de... |
why are the borders of car windshields dotted? | _URL_0_
> It is called "frit"
>
> From an "auto glass specialist":
> Seeing dots on windshields
>
> > Q: Several years ago, black dots started appearing on new vehicle windshields. The dots are usually only around the periphery of the windshield. What purpose do these dots serve? --Brad, Midland, Texas
> >
> > [Steve Coyle, Auto Glass Specialists] The black dots blend the border into the glassA: Windshield glass contains a black enamel band (called the frit) around the periphery that is baked into the glass. This black band includes a border of dots. See figure. The band has an etched surface to enable adhesive to bond to the glass, says a sales manager at Able Auto Glass. When car manufacturers install the windshield, they bond the windshield to the vehicle with adhesive placed on the etched part of the black enamel glass area (inside surface). The outside of the enamel band shades the adhesive from the Sun and protects it from ultraviolet radiation. The band also serves a cosmetic purpose by covering up the adhesive and gives the windshield edge "a more finished look."
> >
> > [Steve Coyle, Auto Glass Specialists] The black dots blend the border into the glass
> >
> > Rather than a straight black edge, the dot border blends the solid band into the clear glass, says Steve Coyle at Auto Glass Specialists. Some windshields also use the dots as a third sun visor to block the Sun behind the rearview mirror where most visors don't reach.
| [
"The windshield (North American English) or windscreen (Commonwealth English) of an aircraft, car, bus, motorbike or tram is the front window, which provides visibility whilst protecting occupants from the elements. Modern windshields are generally made of laminated safety glass, a type of treated glass, which cons... |
If water erodes coasts, why is there still land? How does land grow back into sea? | Well, even fast erosion processes are relatively slow from a human perspective, with some exceptions such as parts of coastal England. You have to remember that even in extreme cases, the coastline represents a small surface area for the water to act on, compared to the volume of the land mass.
The rate depends a lot on the kind of rock that's being weathered as well, with sandy surfaces, limestone and sandstone being more prone than a granite cliffside for example. So there's a lot of erosion, but there's a *lot* of land too, and some of it is pretty resistant to erosion.
You also have volcanic and other geologic processes creating/exposing new land all of the time. Mostly though, it's just a really slow process, and humans haven't actually been around very long. | [
"In this process, land is slowly eroded on the western coasts, while sediments are deposited on the eastern coasts. As a result, western coasts are increasingly protected by human action. The canals between the islands serve as passages for the tides, so that in these places the scouring action of current prevents ... |
George Church, Prof. of Genetics at Harvard Medical School and Director of the Personal Genome Project, will answer your questions | Please forgive my ignorance if the answers to my questions is common knowledge, but I only did a short few weeks of undergrad genetics.
I have often wondered how much an entire genetic code of an individual changes over a life time and if it is significant clinically. Are there any experiments underway /have there been that allow us to track an child's genome as they age and observe the effect of viral inclusions etc.
Also , when you code a genome, what cells do you take the genetic data from? I ask because although all cells would start with the same information, does it happen that over a lifetime , some will have a slight difference to others, due to random mutations in that specific cell line / viral dna in only certain cell types etc ?How is this accounted for? | [
"Mary-Claire King (born February 27, 1946) is the American Cancer Society Professor of Genome Sciences and of Medical Genetics in the Department of Medicine at the University of Washington. She studies human genetics and is particularly interested in genetic heterogeneity and complex traits. She studies the interac... |
What was life like for WW2 German prisoners of war in Britain, after release? | One ex POW you may have heard of was Bert Trautmann who became the goalkeeper for Manchester City and famously played on in a Cup Final despite breaking his neck.
*Trautmann's Journey -from Hitler Youth to FA Cup Legend* by Catrine Clay (Yellow Jersey Press, London , 2010) deals with his experience in POW camps and as an ex POW worker. Now this is of course one man's experience, and mostly based on his own recollections, but it seems people generally treated the POW's well- girls only *too* well at times- Trautmann got two girls pregnant (willingly it seems) and married one of them. And he wasn't alone- according to the book 796 British girls marrried POW's. It wasn't until Trautmann joined Manchester City, apparently. that he encountered much hostility, particularly from Jewish supporters of course.
The author gives a bibliography, though not line-by-line references. I'm guessing the following are her principal references concerning POWS:
Faulk, Henry, *Group Captives, The Re-Education of German Prisoners of War*, Chatto and Windus, 1977
Kynaston, David, *Austerity Britain*, Bloomsbury, 2007. | [
"Large numbers of German prisoners of war were held in Britain between the outbreak of the Second World War in September 1939 and late 1948. Their numbers reached a peak of around 400,000 in 1946, and then began to fall when repatriation began. The experiences of these prisoners differed in certain important respec... |
How did ancient soldiers keep from dying of exhaustion in long battles? | Appian wrote the quote below about the 43 BC Battle of Forum Gallorum during the civil war between Octavian and Mark Antony.
Basically, two lines of men would smash into each other. They would shove and stab opportunistically, but the initial shoving match was more about testing the stamina and willpower of the opposing side. The lines would meet, and a few men would die, and eventually one side would have enough and run. That's when the real killing started.
If you went in slashing, trying to score a lot of kills while the other side was fresh, then you'd probably lose your arm. Each side wanted the other to break and run. It's a lot safer, physically and psychologically, to slash at the backs of a retreating army than at the locked shields of a battle-ready enemy.
"When they grew exhausted, they separated for a short breathing space, just as in gymnastic exercises, and then were locked together again. There was astonishment among the newcomers who had come up, seeing this going on with such discipline and in such silence." | [
"According to this description, the resting place for the night was a poor choice, because it could easily turn into a death trap for sleeping soldiers, who had no space to form themselves for the battle, and no safe way of retreat. In fact, the valley was vast enough to fight a battle of large forces, but for a si... |
how is it possible that our entire universe exists in a black hole in another universe? | We don't know. It's a musing by a few scientists. | [
"Nikodem Janusz Popławski (born March 1, 1975) is a Polish theoretical physicist, most widely noted for the hypothesis that every black hole could be a doorway to another universe and that the universe was formed within a black hole which itself exists in a larger universe. This hypothesis was listed by \"National ... |
how do autistic people see the world? | with thier eyes | [
"Gresha said: “Autistic is the adjective of a development disorder of the brain, NOT a definition of who a person is! Educate yourselves and others on this disorder more common that Down Syndrome or cystic fibrosis. It is four times more common in boys than in girls and is said to be as common as one in every 250 c... |
Other then the green house effect, what effects does an excess of CO2 have on the environment? | [Ocean acidification](_URL_0_) is a major additional adverse effect of excess CO2. | [
"The COfertiliser effect has been greatly overestimated during Free-Air Carbon dioxide Enrichment (FACE) experiments where results show increased CO levels in the atmosphere enhances photosynthesis, reduce transpiration, and increase water use efficiency (WUE). Increased biomass is one of the effects with simulatio... |
How far back in history do you have to go before the world's major languages are no longer intelligible to modern speakers? | Looking at English, Shakespeare wrote about 500 years ago, and the language in his books, while not particularly easy, is intelligible to the modern ear with a bit of effort. Chaucer wrote about a hundred and fifty years before that, and his works, while slightly more difficult, can still be understood.
*As help me God, whan that I saugh hym go*
*After the beere, me thoughte he hadde a paire*
*Of legges and of feet so clene and faire*
*That al myn herte I gaf unto his hoold.*
This was written somewhere between 1386 and 1400, in what's called Middle English. The spelling is strange, but if you sound it out you can make sense of what Chaucer is saying. There was no standard spelling back then, no dictionary either. Heck, Shakespeare himself had 3 different ways of spelling his name.
Now lets go back a bit further. Beowulf was written around the year 1000. Here's the opening line, written in old English:
*Hwæt. We Gardena in geardagum,*
*þeodcyninga, þrym gefrunon,*
*hu ða æþelingas ellen fremedon.*
That is gibberish to the ear of a modern English speaker.
I'm a bit less familiar with the Romance languages (Spanish, French, Italian and Portuguese), but from what I've been told you can go back about 500 years and still understand what they were saying. Further than that it gets difficult. I am not familiar enough at all to speak about other languages.
So, although it will vary considerably from language to language, my estimate would be somewhere around 500 years, give or take a couple of hundred.
Now if you knew Latin you could make yourself understood throughout most of Europe, at least to the educated. Latin was a dead language. It had no native speakers in the middle ages. Even before the fall of Rome the language had split into High Latin (what we today call Latin) and Vulgar Latin. The romance languages evolved out of Vulgar Latin. Because Vulgar Latin was a living language it continued to evolve and change. High Latin, on the other hand, was dead, and therefore static and unchanging. Because it's static and unchanging, yet relatively well known (at least among the educated and the church) you could go back over 2000 years with a knowledge of Latin, possibly as far back as 2500 years. You'd be unlikely to understand the man on the street outside of ancient Rome, but you would be able to communicate with someone. | [
"As of the 2000s, a total of roughly 7,000 natively spoken languages existed worldwide. Most of these are minor languages in danger of extinction; one estimate published in 2004 expected that some 90% of the currently spoken languages will have become extinct by 2050.\n",
"As of the 2000s, a total of roughly 7,00... |
why don't psychologists and psychiatrists work in tandem? | Psychologists and psychiatrists normally work together, more or less. A counseling psychologist will refer a patient to a psychiatrist if they feel the patient needs help beyond what the counselor can provide. For instance, if a psychologist has a patient that's schizophrenic they would refer them to a psychiatrist after the initial diagnosis. If a patient has depression issues the likely course would be therapy with the counseling psychologist and medication and occasional checkups with the psychiatrist to see how the meds are working. If the patient needed behavioral therapy then a psychiatrist most likely wouldn't be needed. | [
"In practice, clinical and counseling psychologists might work with individuals, couples, families, or groups in a variety of settings, including private practices, hospitals, mental health organizations, schools, businesses, and non-profit agencies.\n",
"Clinical psychologists engage in a wide range of activitie... |
how come a hot tub still puts off steam in the winter, even when it isn't hot enough out to evaporate the water? | Believe it or not, it's because it's not hot out that you can see so much steam. The physics behind this phenomenon is identical to cloud formation, where hot, moist air meets cold, dry air. The steam you see is actually water coming out of evaporation (condensing) as it meets the cold air above the hot tub. | [
"Hot tub covers have been shown to reduce most of the evaporative losses from the pool when not in use. With this component of heat loss being 70% a cover with even a small R-value is able to achieve as much as a 75% reduction in heating costs when used as opposed to leaving the water surface exposed.\n",
"Since ... |
How far would the earth need to be from the sun during it's red giant phase to be at the same temperature it is now? | There are a couple of ways to *deal* with our star becoming hotter and larger as it ages. One would be, as you suggest, shielding the Earth from some of the sun's light. The shield wouldn't have to be reflective, although that would help allieviate the buildup of heat on it. You could just build a massive solid wall in space oriented so that it blocked some of the sun's light, and slowly add to it as the sun grows hotter.
This will only work until the sun starts growing larger, though, since as the sun goes into its final stages of life its size will expand to larger than the size of the Earth's orbit. Before this point we would have to *move* the Earth, which is actually possible using a [gravity tractor](_URL_0_) to expand the orbit outward.
The Earth would have to be moved somewhere near the current orbit of Jupiter by the time the sun expands to its largest size to maintain habitability on its surface. | [
"By 2.8 billion years from now, the surface temperature of the Earth will have reached , even at the poles. At this point, any remaining life will be extinguished due to the extreme conditions. If all of the water on Earth has evaporated by this point, the planet will stay in the same conditions with a steady incre... |
Why can't we create life in a laboratory? | The [Miller-Urey Experiment](_URL_0_) did this, with surprisingly good results. Unfortunately for us, it would take a really (really really) long time for anything more than complex molecules to start forming - think about the timeframe of natural evolution. For the record, I am a cell/developmental biologist. | [
"Scientists have speculated about the possibility of creating life non-reproductively in the laboratory. Several scientists have succeeded in producing simple viruses from entirely non-living materials. However, viruses are often regarded as not alive. Being nothing more than a bit of RNA or DNA in a protein capsul... |
I want to learn Mediaeval History of Italy | The difficulty with the historiography of medieval Italy is it is fragmented in case studies of specific cities. This variety makes for an incredibly rich historiography, but an intensely varied one. As far as general, introductory texts, I'm more familiar with English language historiography, but have read fairly widely in the Italian literature. Additionally, while the two are related, very often, northern and southern Italy are separated. This is both problematic and understandable.
Philip Jones's *From Commune to Signoria* is a bit old but amazingly dense and comprehensive account of Italy, focusing on the north. Highly recommended, if incredibly expensive.
Waley and Dean's *The Italian City Republics* is a fine textbook if you want a more accessible—and less expensive—option.
Wickham's newish book, *Sleepwalking into a New World* is quite good, short, and readable. He recognizes how the historiography is fractured and draws together several case studies to draw out general trends. The intro is a good introduction to the historiography of the region as well. Good place to start.
UPenn press has a nice reader of sources to introduce you to the types of sources you might encounter. It's got an unimaginative title, but it's amazing: *Medieval Italy: Sources in Translation.*
Eventually, if you're serious, you'll need to pick a city to focus on, but these books might help you select on. That said, Venice and Florence are fairly tapped out. Not to discourage you, but those cities have been really overresearched. | [
"\"Modern Italy\" is the official journal of the Association for the Study of Modern Italy. Founded in 1995, the journal’s focus is the history, politics and social, economic and cultural studies of Italy, Italian affairs and the Italian peoples from the eighteenth to the twenty-first century. The journal publishes... |
Since photons have no charge, what force or mechanism causes them to deflect/scatter when coming into contact with matter? | Photons don’t have charge, but that just means that they don’t couple to each other. They still couple to particles which *do* have charge. And that’s usually what’s happening: a photon is scattering off of a charged particle.
Scattering of light by light is possible due to higher-order effects, but it’s very rare. | [
"Photons mediate electromagnetic interactions between particles in quantum electrodynamics. An isolated electron at a constant velocity cannot emit or absorb a real photon; doing so would violate conservation of energy and momentum. Instead, virtual photons can transfer momentum between two charged particles. This ... |
why do movie theaters charge seperate fares for different age groups? | To encourage (or discourage!) those groups.
Kids are cheaper because if you get a kid to come you're also getting their parents. It's a 2 for 1 deal as far as the theater is concerned. Families also buy more concessions, which is where most theaters make their real money so encouraging them to come in the door is a big deal. | [
"Many movie theaters, amusement parks, tourist attractions, and other places have different admission prices per market segment: typical groupings are Youth/Child, Student, Adult, Senior Citizen, Local and Foreigner. Each of these groups typically have a much different demand curve. Children, people living on stude... |
[Physics] If strong force is strong enough to keep protons together, why do atoms need neutrons to keep the protons from tearing apart? | You might be tempted to say that the Coulomb force is what prevents all-proton nuclei from existing (except hydrogen-1 obviously). But that's not the full story.
In fact, if you replace all the protons with neutrons, the system is still not bound.
So the **nuclear force itself** simply cannot bind a system of multiple protons (neutrons) without any neutrons (protons). Then of course Coulomb only makes things worse in the case of protons.
The nuclear force between two nucleons can be attractive or repulsive depending on their distance, spin orientations, etc.
If you try to put a bunch of *one* kind of nucleon (either kind) together, they just don't form bound states.
You need protons and neutrons (for A > 1) to have any hope of forming bound states. | [
"Unlike gravity or electrical forces, the nuclear force is effective only at very short distances. At greater distances, the electrostatic force dominates: the protons repel each other because they are positively charged, and like charges repel. For that reason, the protons forming the nuclei of ordinary hydrogen—f... |
If Europeans never settled in the Americas and never took the land from the Natives. How long would the native tribes take to technologically advance and keep up with the rest of the world? | I've just finished reading Jared Diamond's *Guns, Germs and Steel*. According to the thesis he explains, the Native Americans would probably never have become industrialised - unless they borrowed or stole technology and animals & plants from the Europeans.
The reason that the North American natives were less advanced than Europeans (and I'm going to simplify here!) was because of the lack of animals able to be domesticated and plants suitable for agriculture in the Americas.
The only animals to be domesticated there were the llama and alpaca in South America. Because of the difficult geography between the Andes and Mesoamerica and North America, these domesticants never spread out of their local area. They didn't spread to Mesoamerica, where the natives had invented the wheel - but had no pack animals to take it to the next level. They didn't spread to North America - where there were villages producing low-level crops of corn.
The most advanced crop in the Americas was corn/maize, which produced about 1/10th of the protein of wheat.
Therefore, with no farm animals, and only barely adequate crop plants, the North Americans had no strong incentive to form primarily farming and herding societies. They *had* to remain at least partly hunter-gatherers. They therefore couldn't produce enough food to support people who didn't produce food. Therefore, they wouldn't have been able to support a metallurgy industry or other types of technology.
So, the North Americans were *never* going to industrialise, because of their geographical limitations.
However, if the North American natives encountered the Europeans and were able to acquire farm animals and better crops from them, they could have progressed further. Assuming the Europeans would have left them alone, that is.
*EDIT: Wording errors.* | [
"From the beginning of the European colonization of the Americas, Europeans often removed native peoples from lands they wished to occupy. The means varied, including treaties made under considerable duress, forceful ejection, and violence, and in a few cases voluntary moves based on mutual agreement. The removal c... |
how do companies like trivago and webjet actually make money? | In reality, these places aren't getting any real special rates... they're typically getting the same discount off "rack rate" all travel sites, and even the hotel websites show. These websites act as online travel agencies -- they are referred to as OTA's in the industry. Just as in the past, airlines or hotels would pay a commission to travel agents for booking their customers on their particular flight or hotel, they today pay OTA's a commission for each booking. Just a different sales channel than if the hotel's call center took a call and paid a commission to the rep or a traditional travel agent booked a ticket for a customer. Now the commissions have gotten much smaller than they were and are now typically fixed instead of a percentage... but for a website booking millions of flights, rooms, cars, etc. per year it adds up. So they may get $20 for every hotel room night booked from Hyatt brands, and 15% of room rates at Hilton, etc. Airlines are tiny commissions, like $5 a flight segment... but hotels pay 10-25% typically. | [
"On 24 June 2013, Easy Taxi received Series B investment from Latin America Internet Holding (LIH) a joint venture between Rocket Internet and Millicom, securing another $15 million. At that time the company stated it had more than 1 million downloads and 30000 drivers in the network. The new funds were intended fo... |
Why do people faint because of low blood sugar when they haven't had a meal for a long time if the body can turn stored glycogen into glucose? | This shouldn't happen. If it does, it's a sign that something's wrong with glucose control. One way in which a person can go hypoglycemic is too-high an insulin level or 'ringing' insulin (high then low then high again) levels. This shouldn't happen in healthy individuals, though. Eating too many 'fast' carbs at once then fasting for a while can trigger it in unhealthy individuals.
People that go hypoglycemic when they haven't eaten in a while probably have some other metabolic issues as well and they may be pre-diabetic and/or they may already have metabolic syndrome or may get it at some point in the future. In healthy individuals this should not happen.
You are right that some amino acids and at least the glycerol backbone of triglycerides can be turned into glucose via gluconeogenesis in the liver. Contrary to popular belief, the brain can feed off other substrates besides glucose. Glucose is obligatory for only a small portion of the brain.
After some time without food the brain can switch to ketones as a fuel source. These are fat-derived molecules that can pass the blood-brain barrier. The body generates ketones from fats (some amino acids are ketogenic too) in order to conserve glucose when glucose reserves are low. Thus sparing muscle tissue from being catabolized for its gluconeogenic amino acids. Individuals undergoing ketosis have a brain glucose requirement that drops from over 125g a day to under 25g a day. So ketones very much spare glucose.
EDIT: More about ketones. Individuals that are starving and are in ketosis (that is, they have significant levels of ketones in their blood) have been injected with insulin in experiments. Their blood glucose level shot as low as 20 mg/dl, a level which would cause a normal individual to go comatose. Ketotic individuals displayed no apparent symptoms of hypoglycemia when glucose shot down this low, thus confirming that the brain can run very well off ketones when starving or on a low carbohydrate diet.
| [
"Hypoglycaemia occurs when blood sugar levels drop too low; it can cause a variety of symptoms including hunger, sweating, rapid heart rate, and shaking. If left untreated, hypoglycaemia can lead to a loss of consciousness. Onset of hypoglycaemia can be sudden, requiring glucose levels to be normalised by consuming... |
penis envy | Basically it was Sigmund Freud's theory that women secretly wish to be men.
Along with a lot of Freud's other theories on child sexual development, its been largely discredited. | [
"Penis envy () is a stage theorized by Sigmund Freud regarding female psychosexual development, in which young girls experience anxiety upon realization that they do not have a penis. Freud considered this realization a defining moment in a series of transitions toward a mature female sexuality and gender identity.... |
Why is Sun Yat-sen still so revered in China, if he's the founder of the Republic of China, which still opposes the current PRC? | The Mandate of Heaven. Let me explain. The Mandate of Heaven stipulates that dynasties start with the right to rule and then become increasingly incapable, until disasters begin to occur, signalling the need for a renewal of the dynastic cycle. As a result, the actions of later emperors of a dynasty can be safely disentangled from their predecessors, who are judged far more kindly.
It was generally the case that ruling emperors reserved the exclusive right to give offerings at the tombs of prior emperors, even – indeed especially – of *previous* dynasties, and the founders of the one immediately prior got special treatment by virtue of being the renewers of the cycle. Hence the Qianlong Emperor would sacrifice at the tomb of Zhu Yuanzhang, the Hongwu Emperor of the Ming, whenever visiting Nanjing. Sun can be seen in a similar light.
While Sun founded the ROC (Republic of China) and the KMT (*Kuomintang* – Nationalist Party), it can be construed that it was the ROC and KMT *as run by Chiang Kaishek* – who essentially took command of it by coup – that abused the Communists, allegedly mishandled the war with Japan, and established the rebel state on Taiwan. Sun, being the apparent founder of the republic, can therefore be both a righteous figure (having overthrown the corrupt Qing) and be absolved of the crimes of his successors.
China's relationship with the republican period and even KMT imagery is actually quite complex, and isn't merely black and white. For example, the 'Revolutionary Committee of the Chinese Kuomintang', a left-wing splinter of the Kuomintang proper using, among other things, the white sun on a blue background as its emblem, is an officially registered political party on the mainland, and the ROC flag used on Taiwan, which again has the KMT star, remains used as a symbol of mainland nationalism. | [
"Sun Yat-sen remains unique among 20th-century Chinese leaders for having a high reputation both in mainland China and in Taiwan. In Taiwan, he is seen as the Father of the Republic of China, and is known by the posthumous name \"Father of the Nation, Mr. Sun Zhongshan\" (, where the one-character space is a tradit... |
During the height of the Cold War, how would full-scale nuclear war have been carried out? | What you are asking for is the "order of battle" — obviously such things are speculative but one can, with some effort, line up the various forces and doctrines and come up with things that are at least plausible. Robert Norris has been doing this sort of thing for a long time in a professional context, working for the Federation of American Scientists; you might check out his [Order of Battle for the Cuban Missile Crisis](_URL_0_). It is to my knowledge the most up-to-date of such approaches, taking into account exactly what we currently know about the composition of forces of both sides. | [
"The conflict continued to escalate, with the major superpowers developing long-range missiles (such as the ICBM) and a nuclear strategy which guaranteed that any use of the nuclear weapons would be suicide for the attacking nation (Mutually Assured Destruction). The creation of early warning systems put the contro... |
There is no/less Russian spy novel of cold war period? | There are actually some Warsaw Pact versions of Bond. The most famous is by Bulgarian author Andrei Gulyashki. His character Avakum Zahkov is a counter-espionage agent with above-average intelligence and devotion to the system. Many of his missions involve the protection of scientists and various technological advances pioneered by Warsaw Pact nations. In a mid 1960s novel, he actually is forced to confront a British agent whose code name of 07 is a clear Bond reference. Zahkov and Bond fight, with Zahkov prevailing and killing 007 in hand to hand combat.
There aren't a lot of sources on it, best I've come across is Alexis Albion's article "Wanting to be James Bond" in the book *Ian Fleming and James Bond: The Cultural Politics of 007* | [
"After the Russian Revolution (1917), the quality of spy fiction declined, perhaps because the Bolshevik enemy won the Russian Civil War (1917–23). Thus, the inter-war spy story usually concerns combating the Red Menace, which was perceived as another \"clash of civilizations\".\n",
"\"The Spy Who Came in from th... |
Why did we have the dark ages? After so much forward thinking by the ancient Greeks and technological advances by the Roman Empire- did everyone just forget it? Shun it for some reason? Could we be any more advanced of the dark ages never happened? | At a basic level, we kind of didn't have them. Despite what a lot of common knowledge (including this infamous [chart](_URL_1_)) would have you believe, the world didn't just slip into barbarism when Rome fell. The idea is very eurocentric, ignoring the advances and civilisations that existed throughout the world. Mesoamerica, the Middle East and Eastern Asia all had complex, city building, stuff inventing cultures while the 'Dark Ages' took place in Europe.
Even in Europe, the analogy falls apart. Especially when you consider that the eastern HALF of the Roman Empire, what is now referred to as the Byzantine Empire, survived for the better part of a thousand years longer and maintained or improved on the technology that had been used in Rome.
This [FAQ](_URL_0_) is a good resource and has links to tons of useful threads on the subject of the "Dark Ages". | [
"The historians had defined the Greek Dark Ages, a period of general decline, in this case the disappearance of the palace economy and with it law and order, loss of writing, diminishment of trade, decrease in population and abandonment of settlements (destroyed or undestroyed), metals starvation and loss of the fi... |
Where does the classic image of the Roman Infantry shield come from, how much variation in pattern was there? | The classic image of the Roman shield, or *scutum*, is one of the most iconic images of the Roman Empire. It was one of the biggest contributors to the success of Roman legions on the battlefield due to its invaluability in defense and offense. Along with the short sword *gladius*, the two could take down the most formidable opponent.
* Where does the classic image of the Roman Infantry shield come from?
It comes from the standard army shield during the Roman Empire. This shield has evolved drastically overtime - at first, it was oval and flat because early Romans (pre-Samnite Wars) fought in phalanx formation. These shields would look similar to the Greek [shield](_URL_2_. However, after the Romans adopted their classic manipular system, these shields became obsolete. They slowly evolved to a larger, elliptical shield (probably similar to the Samnites) and then to a more cylindrical shield that almost entirely protected the user. This is the classic [shield](_URL_1_) you are thinking of. This shield was in use during the best (opinion) times of the Romans, from the middle Republic to the middle Empire. The *scutum* of the Late Roman Empire was elliptical and flat. I'm actually not sure why they changed it, as my knowledge of the Late Empire is not as thorough, but if I could guess (so take this with a grain of salt) it would be because the Romans relied heavily upon mercenaries later on. Perhaps the later shield was more akin to what the mercenaries were used to, I don't know, or maybe there was a heavy Eastern influence since the Eastern Roman Empire became the focal point in the Mediterranean. I should let someone answer that.
* How much variation in pattern was there?
So this is cool - each legion had its own symbol, and this symbol would be on their shields. During the Battle of Thapsus, Caesar's fifth legion withstood and repelled an elephant charge and was rewarded with the symbol of the elephant. This would give great pride to all members of the legion and be a reminder of when they performed at their bests, so they would put this symbol on their shields. Another example is that some shields have a wreath on them, the Roman symbol for victory. So this [guy](_URL_3_), on his shield is a wreath, meaning victory, and a bull, which is a common symbol of many Roman legions, like Caesar's third legion. These shields were very important to a Roman warrior and were highly decorated to signify the strength of the Romans and give pride to the man wearing it. Hope that helps!
Sources - primarily [Roman Warfare (Smithsonian History of Warfare)](_URL_0_)
edit* cause my jokes aren't funny, also sources | [
"The classic legionary \"scutum\", a convex rectangular shield, also disappeared during the 3rd century. All troops except archers adopted large, wide, usually dished, ovoid (or sometimes round) shields. These shields were still called \"Scuta\" or \"Clipei\", despite the difference in shape. Shields, from examples... |
why does ground coffee not coagulate like other powders? | So coagulation only applies to fluids, solid powders cannot coagulate by definition. I believe what you're referring to is clumping, which is almost always due to moisture. The powder will stick to wet surfaces/itself trying to absorb water. This is only present in soluble powders, or essentially dehydrated mixes which usually contain a lot of sugar. Sugar causes the behavior you're describing of cocoa powder, but since coffee grounds do not contain sugar nor are they water soluble they don't have the same behavior to moisture. | [
"The caffeine in coffee \"beans\" serves as a toxic substance protecting the seeds of the plant, a form of natural plant defense against herbivory. Fruits and leaves also contain caffeine, and can be used to make a tea. (See: Coffee cherry tea) The fruit is also used in many brands of soft drink as well as pre-pack... |
As we get older, we “lose” telomeres - does this mean a child born to a dad that was 80 as opposed to the same dad at 40 would have shorter telomeres? | As organisms age, their telomeres get shorter. However, there's an enzyme called "telomerase" that can repair telomeres and fill them out to full length again. Telomerase is normally only active in a few regions of the (adult) body. One place that telomerase is very active in the testes, where it causes sperm telomeres to be full length. The same is true in female egg cells.
> To counteract this shortening, certain types of cells, including stem cells, male/female germline cells, granulosa cells, early embryos, and most cancerous cells, express an enzyme known as telomerase, which has the potential of restoring the shortened telomeres. Presence of telomerase activity in the male germ cells ensures maintenance of telomere length at maximum levels during spermatogenesis despite telomere attrition due to DNA replication or other genotoxic factors.
--[Telomerase Activity and Telomere Length in Male Germ Cells](_URL_1_)
So older men don't have short sperm telomeres. (There's been some suggestion that older fathers may actually have longer sperm telomeres, though it's not clear that's completely accurate.) However, there is some evidence that older men do, on average, have [slightly less healthy children](_URL_0_), for other reasons -- telomeres are not the only, or even most critical, factor in longevity and health.
| [
"Telomeres are repetitive genetic sequences at both ends of each chromosome that protect the structure of the chromosome. As men age, most telomeres shorten, but sperm telomeres increase in length. The offspring of older fathers have longer telomeres in both their sperm and white blood cells. A large study showed a... |
why do some people cross the number 7 like a lowercase t? where did this come from? | Because some people's 7s look like 1s - Most do it so others won't mistake their 7 for a 1. | [
"William Barclay notes that, because the letter T is shaped exactly like the \"crux commissa\" and because the Greek letter T represented the number 300, \"wherever the fathers came across the number 300 in the Old Testament they took it to be a mystical prefiguring of the cross of Christ\".\n",
"There is a need ... |
in the islam religion do women pray in mosque's or only men? | Women usually pray in different part of the Mosque, most likely behind the men or in the different floor than men. | [
"According to a saying attributed to Muhammad in the hadith Sahih Bukhari, women are allowed to go to mosques. However, as Islam spread, Muslim authorities stressed the fears of unchastity from interaction between sexes outside their home, including the mosque. By pre-modern period it was unusual for women to pray ... |
How is the FDA able to approve certain drugs without knowing the exact mechanism of action? | If there is a pill that is shown to cure cancer and cause minimal side effects does it matter if we know how it works or not? Let's say we find out through extensive testing it causes nausea in 1/1,000 patients but cures cancer in 99/100. It is not safe in that it causes nausea but I'd still be on board if it is almost guaranteed to cure me.
At the moment we can't model the exact mechanism of action of turbulent flow at a molecular level around an airfoil, but we can use large scale probability to make a plane fly time after time.
Before going any further I would like you to define "*truly* safe" which you mention in your question. | [
"The FDA has a \"priority review process\" for drugs which compete with another drug whose price exceeds its value-based price. Congress could also grant the FDA the ability to change the exclusivity period for new drugs. The FDA could also temporarily allow the import of drugs approved for sale outside the United ... |
Why do we record 4k in 4:4:0 instead of 1080p at 4:4:4? | Are you thinking 4:2:0 instead of 4:4:0? I haven't seen 4:4:0 used before.
It is true that 2160p/4k video at 4:2:0 has the same chroma resolution as 1080p at 4:4:4, which is the point of the question I think.
However, our eyes are not that picky about chroma. Luminance is by far the most important factor in our eyes' ability to see detail, and the first number in 4:2:0 indicate that no subsampling is going on there with luminance.
4:4:4 or 4:4:2 is better than 4:2:0, but in bandwidth constrained situations, the perceptual difference is almost zero. However, when working with raw video, most cameras and codecs (at the professional level) will maintain 4:4:4 or 4:2:2 as much as possible to retain details for post production, editing, and color correcting. But once the final version is rendered, that much color detail is overkill for final distribution (similar to how having a RAW image from a camera is overkill for displaying on the web, jpeg is fine), so it's fine to distribute in 4:2:0 in h264 or h265 formats
(Edited to correct and add a couple things) | [
"More over, the AVC-Intra Class 50/100 is now extended to Class 200 and Class 4:4:4. The Class 200 mode extends the bitrate to 226 Mbit / sec for 1080/23,97p, while the Class 4:4:4 extends the possible resolution from 720p to 4K with pixel depths at 10 and 12 bits.\n",
"In practice, 1080p typically refers to a 19... |
when kim jong un is having talks with president xi of china, do they speak a common language, or do they have interpreters? if interpreters are used, who's vetting the translation? | They most likely use translators. Kim Jong Un’s foreign language skills are in English, which he learned going to an English-language international school. Xi Xinping probably speaks some English from time he spent in the USA in the 1990s, but isn’t fluent. | [
"In the case of translation, the languages tested were the four which the Joseon court maintained translators in: contemporary Chinese, Mongolian, Jurchen/Manchu, and Japanese. This examination was overseen by the Office of Translators, which maintained translators in the capital and in the major border-ports and c... |
why is a decreasing population considered a bad thing for a country? | People are an input into the economy, just like oil or farm land or machines. As a general rule, the more people you have, the more you can produce. So, on a surface level, a shrinking population is bad for an economy in the same way that a dwindling oil supply or lack of capital is bad.
Unlike most of those things, people also create demand, not just supply. So fewer people can also mean that people aren't out there looking to buy new stuff---especially land and houses. which can also upset the economy quite a bit.
On top of that, shrinking populations also usually mean aging populations. As people get older they tend to go from being net producers to net consumers, especially when health deteriorates. This can force a country to make hard choices about how, and how much, to support an older population that increasingly can't support itself. This is made worse by the fact that some jobs simply aren't suited to older people (There are very few 80 year old coal miners, or 70 year old ER nurses, and even when people are only 40 or so they may find that family and health makes it hard to work the kind of job or hours they could have worked when they were 50.)
| [
"His conclusion is that poverty is the main cause of the population crisis. If the reason behind overpopulation in poor nations is the exploitation by rich nations made rich by that very exploitation, then the only way to end it is to \"redistribute [the wealth], among nations and within them\".\n",
"Population g... |
Why can something you normally like taste bad because you expected it to be something else? | NOTE: NOT A SCIENTIST, JUST SOMEONE WHO ENJOYS SCIENCE
I believe it's probably more psychological than anything. The expectation of one result, with a different actual result, creates surprise, which, in combination with it being a food product, can often result in revulsion, because if something tastes unexpected, it's usually an indicator that it's gone bad. Thus the initial surprise/disgust/gagging, as a reflex to protect the body from ingesting something that could be harmful.
Any scientists want to confirm/deny this theory? | [
"Taste can be objective in terms of the five tastes (sweet, salt, sour, bitter, and savory) but it can also be subjective in terms of what we deem \"good\" and \"bad.\" Taste is \"subjective, objective, and qualitative\". In terms of it being a philosophical concept, taste is hard to define because it is essentiall... |
What happened to Peers from the colonies after the American Revolution. | They left, yes. Most were not permanent residents in the first place, so they were simply returning home.
As far as giving up titles goes, that didn't/couldn't happen. The title itself belongs to the person regardless of their country of residence. Even if they choose not to use the title, it's still theirs. The law on the books from 1648 was that the person inheriting the title was ennobled whether they wanted to be or not. This actually didn't change until 1963, and even now there's just a small window of time where someone can disclaim a title immediately after inheriting it. This only lasts for the duration of their life, however. It still passes to the heir upon death.
There was only one peer in permanent residence in the American colonies - Scottish Lord of Parliament (equivalent to an English Baron) Thomas Fairfax, 6th Lord Fairfax of Cameron, from Virginia. Most of his lands were confiscated in 1779, but he personally was never bothered. He died in 1781, and his title passed to his younger brother (living in England). The family later received remuneration from the British Parliament for the lost property. Interestingly - the 7th Lord Fairfax of Cameron also died without issue, and the title then passed to a nephew, American-born Bryan Fairfax (incidentally, a good friend of George Washington). The family stayed in the US, and kept the title until the 12th Lord Fairfax moved back to the UK. Despite being American-born, the 12th Lord later served in the House of Lords as an elected Scottish Representative Peer.
The other name that comes up in the context of peers during the American revolution is William Alexander, Lord Stirling. He tried to claim the title of 6th Earl of Stirling after the 5th Earl died in 1739. The 5th Earl was his cousin through marriage. The House of Lords denied his claim. He inherited the estate, but not the peerage. He was, however, granted the courtesy style of "Lord Stirling," and he did use it, even while serving in the Continental Army. | [
"In the 1780s with the end of the American Revolutionary War, hundreds of black loyalists, especially soldiers, from America were resettled in London. Later some emigrated to Sierra Leone with help from Committee for the Relief of the Black Poor after suffering destitution. However, they were never awarded pensions... |
On the recycling of electronics. | My post may not have enough details, but I once worked for a company that recycled old computers. The good ones went to schools while the broken or very old ones were recycled. I was told that motherboards and circuitry was to be submerged in a vat of (some sort of ) acid so that the precious metals can be reused.
Perhaps this [link may be informative](_URL_1_). Ditto for [this](_URL_0_). | [
"Electronics recycling, or ecycling, is another focus for Waste Management. This refers to the proper disposal of electronic items like televisions, computers, microwave ovens, cellular phones, VCRs and DVDs and other such products. The U.S. Environmental Protection Agency (EPA) encourages consumers to reuse and re... |
how can the us senate change their own rules as they go along? | If there is not a quorum (for the Senate this is a supermajority of 60%) but all those that are present unanimously vote to disregard that requirement they are able to continue voting on issues. This is not "changing the rules" really as it is an existing option for them. This was originally implemented so that they could pass needed laws even if more Senators than normal are ill or otherwise unable to attend. For the Senate specifically they still need a majority (51) votes on any issue for it to pass, but they do not need the supermajority of 60 for it. | [
"The Standing Rules of the Senate are the parliamentary procedures adopted by the United States Senate that govern its procedure. The Senate's power to establish rules derives from of the United States Constitution: \"Each House may determine the rules of its proceedings...\"\n",
"The Senate is meant to regulate ... |
If the universe is quantum fluctuation, why is it so big? | I'm not sure specifically what kind of quantum fluctuation models you're talking about, but there are two things I can say that might help answer the question.
The first, and maybe the less helpful, is that if we are a giant quantum fluctuation there is no reason that we must exist in the smallest quantum fluctuation necessary for life. Probabilities don't work this way. Even though our fluctuation is more unlikely than the minimal one, this is the one that happened.
The second, and maybe more helpful, is that when talking about the creation of universes people often talk about the probability of making a big bang, which is a point-like object. These big bangs then evolve into giant universes according to rules similar to the big bang that created our universe. The analogy often used is the creation of a universe is like a bubble created in a kettle of boiling water. The bubble appears, seemingly our of nowhere, and grows bigger and bigger. | [
"Due to the quantum geometry, the Big Bang is replaced by a big bounce without any assumptions on the matter content or any fine tuning. An important feature of loop quantum cosmology is the effective space-time description of the underlying quantum evolution. The effective dynamics approach has been extensively us... |
different funds. hedge funds, mutual funds, etc. | To understand these you have to have basic information of the stock market. today Apple (AAPL) is valued at $462.81 per share; Google (GOOG) is $884.80 Yahoo is $27.86. You can't just buy one share of any of these they would be sold in bundles of 100, 500, or 1000 shares.
If you bought 1000 shares of AAPL and AAPL tanked you would loose big. On the other hand if you bought shares of all three you would have a better chance of not loosing because the risk is spread out between the three. If you had to buy 1000 share of all three that would total at $1,377,470. Not everyone has that much cash on hand but say you got 100 friends together and each pitched in $13,774.70. That way 100 people would have a relatively small investment in 3 companies.
A Mutual Fund work the same way but it uses money from thousands of investors and puts it in to hundreds or thousands of different stocks. diversifying like this helps to alleviate some of the risk.
A hedge fund works in the same way but it is not open for people. It is more for large banks, investment bureaus and 401Ks.
The whole idea for either one is to allow the investor to spread out the risk over a larger portion of the market. | [
"A hedge fund is an investment fund that pools capital from accredited investors or institutional investors and invests in a variety of assets, often with complicated portfolio-construction and risk management techniques. It is administered by a professional investment management firm, and often structured as a lim... |
have any technologies peaked? | Firearms. We can keep making them to tighter tolerances by shaving off thousandths of inches here and there, but the fact is the designs are pretty much perfected. You can't do much to alter the basic physics involved in feeding bullets into a gun.
Even experts agree that unless a radically new kind of technology shows up (like directed energy weapons) the basic design of a gun isn't going to change much. There have been some innovations like the Kriss Vector, but results have been mixed and the jury is still out on it. | [
"A key factor in production of new technologies is whether it is cost effective and useful. Devices that make use of cryoelectronics and the applications of superconductivity such as computers, information transmission lines, and magnetocardiography have potential for commercial value outside of a few specific devi... |
It seems like up until the middle of the 20th century most cities in the U.S. were laid out in a grid pattern, then that idea was abandoned. Why? | In Denver, and most other cities of the American West, the difference is primarily on the residential "side streets." The grid of section-line roads at one-mile intervals (92nd Ave., 104th Ave., 120th Ave., 136th Ave.; Chambers, Buckley, Tower, etc.) generally either was there prior to development or was strengthened in conjunction with development. Perhaps for topographic reasons, very few section-line roads were ever built in the areas south of Denver, so even arterial patterns have been left to modern planners and traffic engineers.
The *sections* marked by these roads (the [Public Land Survey System](_URL_0_) ) were the basic module for sale of farm- and ranchland in the 19th century. East of the Mississippi, farms were typically 40 or 80 acres; west of there, settlers often were allowed to homestead entire quarter-sections of 160 acres. Out West, in ranch areas, entire square-mile sections could be claimed. As later urbanization engulfed farmland, subdividing a 40-acre farm parcel with two east-west and four north-south streets was a quick and easy way to plat an *addition* to a town and sell new houselots.
The undifferentiated gridiron layout for “additions” to cities was criticized in the early 20th century as insensitive to topography, wasteful, and ill-suited for growing auto traffic. When the Federal Housing Administration was established in 1934 to guarantee mortgages, homebuilders saw it as devoted to ensuring the success of their projects rather than as governmental interference, so they were much more receptive to FHA’s underwriting criteria than to local subdivision regulations with similar aims. FHA’s 1935 technical standards suggested that streets should fit the local topography and have widths suited to their requirements (not be overbuilt on the assumption that every lot might someday contain a factory or apartment house). FHA standards also promoted the “functional classification” familiar to us (arterials, collectors, local streets) that had been made necessary by the growth of auto traffic. “Best principles” publicized by homebuilder organizations Urban Land Institute and National Association of Home Builders and by planning officials of American Society of Planning Officials and the American Institute of Planners during the 1940s followed similar concepts, recommending loop and cul-de-sac layouts that followed local topography and efficiently subdivided often-irregular parcels. Cul-de-sacs branching off collector streets were promoted as the most attractive layout for single-family dwellings.
Postwar homebuilders initially turned to modified grids to relieve the “monotony” of long, straight local streets, but research in the 1950s by traffic engineers seemed to show dramatically lower accident rates for T intersections and bending streets. By the 1970s, homebuilders increasingly favored cul-de-sacs even in places where the terrain was completely flat.
From the late 1980s, planners began to note the drawbacks for pedestrians and cyclists of cul-de-sacs and the functional classification system. The movement initially known as neotraditional development (later the New Urbanism) promoted permeable networks that didn’t push all traffic onto collectors and arterials, and that allowed pedestrians and cyclists to take reasonably direct paths through neighborhoods.
Probably the best source on this subject is Michael Southworth and Eran Ben-Joseph, *Streets and the Shaping of Towns and Cities,* though it can be instructive to look at ASPO/AIP/APA publications for city planners, and at the ULI *Community Builder’s Handbook* and *Residential Streets.* | [
"In the westward development of the United States, the use of the grid plan was nearly universal in the construction of new settlements, such as in Salt Lake City (1870), Dodge City (1872) and Oklahoma City (1890). In these western cities the streets were numbered even more carefully than in the east to suggest fut... |
Critiques of historical dictionaries | A simple research on « “historical dictionary” review » can offer you several interesting examples, especially if you happen to have access to JSTOR (you may also try to search for specific dictionaries followed by the same word). More specifically, the *TLS* published a very interesting review of the *Virgil Encyclopedia* two weeks ago; even though it is not technically a historical dictionary, the framework is reasonably similar. But overall, I am not sure that you will find reviews very helpful; criticism tends to focus on editing and coordination (quality of the cross-references, missing articles, uniformity in terms of formating), not on the contributions — mostly because an individual reviewer rarely has the knowledge to analyse accurately contributions made by dozens of different academics. | [
"The dictionaries tend to follow a uniform format of a chronology, introduction, the historical dictionary, and a bibliography with supplementary material such as maps, abbreviations, place name changes, or notes on language according to the subject. The main section is the historical dictionary which covers events... |
What was the state of cryptography during WWII? What codes had the Allies and the Axis broken? How was that information used? | In brief, what I am aware of includes:
The British had a whole cryptology department at Betchley Park whose sole job was to decrypt German communications.
One of the rumours from the Battle of Britain was that the Luftwaffe Enigma code had been broken and Hugh Dowding was reading the targets for the next day... This allowed him to deploy his forces accordingly and took some of the reliance off of radar.
The Poles had broken the Enigma codes before the war started, but I don't know what happened with the info after that.
The Kreigsmarine Enigma codes weren't really broken until the U571 was captured. This information was then used to hunt U-Boats and route convoys away from the Wolf-packs.
The Japanese Naval Codes had been broken before Pearl Harbour but a number of miscommunications resulted in the tragedy at Pearl Harbour. | [
"German code breaking in World War II also had some success, most importantly by breaking the Naval Cipher No. 3. This enabled them to track and sink Atlantic convoys. It was only Ultra intelligence that finally persuaded the admiralty to change their codes in June 1943. This is surprising given the success of the ... |
how come we sometimes all of a sudden start nosebleeding? | I'll try and share what little knowledge I have. I used to be a long sufferer of constant nose bleeds that were quite rapid. According to doctors that I saw regularly, the bleeding was caused and is commonly caused by a vein very close to the surface of the skin inside of your nose. And in some cases, it may enlarge and break the skin, causing a bleed. The enlarging may be caused by a number of factors, I was told changes in temprature or heartrate could enlarge it! Hope this was helpful, I'm no expert!
| [
"Prestopped nasals and prenasalized stops occur when the oral cavity is closed and the nasal cavity is opened by lowering the velum, but the timing of both events does not coincide. A prenasalized stop starts out with a lowered velum that raises during the occlusion, much like the [nd] in \"candy\". A postnasalized... |
In the Ancient world tin was an extremely rare (and important) resource and England was famous for being a source of the metal. What was life like for those miners before the advent of modern mining techniques? How did they mine and transport tin? | First to pick a couple of nits: ancient tin mining in Britain was during a period before the term "England" had a meaning; and - to save you from an angry Cornish mob - tin mining occurred in Cornwall, which most Cornish regard as distinct from England. Tin mining was important in Britain because of the Cornish reserves (although the same lode - a mineral-bearing vein in Cornish dialect - manifests in the southwest of Ireland as well).
Early mining in Cornwall took two forms: the first and easiest was conducted by what were called "steamers." These miners worked the streams of Cornwall to pick up tin ore that had been washed and exposed by action of the water. Some digging could occur with a process not unlike what the earlier '49ers employed in the California Gold Rush.
There was also some subsurface mining. Archaeologists have occasionally exposed these old works and found antler picks and limited timbers to serve as structural supports (the same sort of technology was used by flint miners elsewhere in Britain). Dewatering was a constant problem that was largely unaddressed, so depth was limited. Work underground wasn't safe, but it was likely not more dangerous than what occurred in the pre-industrial and industrial periods. I find the depiction of mining in the recent BBC/PBS Poldark series to be satisfying for that later period. That level of technology began to settle in during the late middle ages and was perfected over the centuries by a series of technological advancements. During the nineteenth century the industry settled into a form that could be regarded as "modern" underground mining. | [
"Tin mining in Britain took place from prehistoric times, during Bronze Age Britain, and until the 20th century. Mention of tin mining in Britain was made by many Classical writers. Tin is necessary to smelt bronze so without tin there could not have been the Bronze Age. As South-West Britain was one of the few par... |
why can't they restore the area around the nazca lines? | There is so little wind erosion, and there is virtually no water erosion. Every footprint, tire print, and the like will last for centuries if not millennia. No matter how meticulous we are in landscaping we cannot undo all of that because the landscaping itself destroys the area. | [
"Gazit's Red Line Project has been installed in the sinkholes of the Dead Sea in Israel, melting Knik Glaciar in Alaska, the Great Salt Lake in Utah, and the Salton Sea in California. He has planned future installations along the Amazon river, the forests of the Sumatra and Borneo, and the floating islands of garba... |
How accurate is Marco Polo's account of the Mongolian empire? | First of all, I should mention that one of the biggest critiques of Marco Polo comes from Frances Woods, *Did Marco Polo Go to China*? Among other glaring issues, Polo never mentions the Great Wall of China and a number of other items that one would expect a visitor to mention in an extensive account.
The other issue with the text is it's Frankenstein manuscript tradition. *The Travels* were copied down so many times with different stories, it's hard to know what's original and what is not. I was in a seminar in which we discussed Marco Polo and a friend wrote a paper about the elements of romance literature found in the text, suggesting that elements of Polo's account should be seen more as literature rather than a straight up travelogue. Indeed, the Rustichello da Pisa, individual who actually wrote the thing based on Polo's supposed recollection, was an author of romances.
Perhaps the most convincing version is one written/copied by a Monk that is more of a list of events rather than any sort of Romance.
In my personal opinion, unless someone provides a significant recounting of the manuscript tradition coupled with reasons why they are using specific elements of Polo's account, *The Travels* barely meet the requirement for valid historical evidence for the Mongolian Empire. There are a number of (admittedly problematic) European accounts of the *Pax Mongolica*.
*The Travels* are much more useful for understanding how medieval Europeans saw the world. Its popularity means that we can use the text to reconstruct how medieval Europeans saw their place in the world. | [
"During his extensive research, show creator John Fusco traveled the Silk Road by horseback and also crossed the Ming Sha Dunes of Western China on camel. In Venice, Italy he sought out and studied the \"Last Will and Testament of Marco Polo\". While some Mongolian viewers and experts view it as \"riddled with hist... |
What is the mechanism that controls seasonal fur growth in mammals? | There have been studies to suggest that melatonin levels are responsible for seasonal cycles in animal systems. Melatonin levels increase during periods of higher levels of darkness. Basically, longer nights = more melatonin. When threshold levels of melatonin are reached, it can trigger a biological phenomenon like fur growth.
So, as the days get shorter, the melatonin levels get higher on average, providing the animal with an internal clock that works both daily and yearly. | [
"Similarly, bird plumage and mammal fur change with the approach of winter, and is triggered by the shortening photoperiod of autumn. The circannual cycle can also be useful for animals that Migrate or Hibernate. Many animals' reproductive organs change in response to changes in photoperiod. Male gonads will grow d... |
why was the change from cellular 3g to 4g such a complicated thing, when 2g to 3g happened with no fuss? | Because when 3G first rolled out the term smart phone didn't exist and most people hadn't heard of data plans. 4G on the other hand is rolling out as mobile data usage is exploding. | [
"By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by the growth of bandwidth-intensive applications, such as streaming media. Consequently, the industry began looking to data-optimized fourth-generation technologies, with the promise of speed improvements up to ten-fold over existi... |
- how do touch screens work? how can i use a stylus on my 3ds, but not on my iphone? | There are two types the one for the 3ds works through touch from anything either a finger, stylus, stick ect. The other works via electricity such as your finger to an iphone screen. Certain stylus' work on iphones by having a metal body which transfers the electricity. | [
"Touch screens like those found on some tablet computers, iPads, and the Nintendo DS are operated in similar ways, but they usually use either optical grids or a pressure-sensitive film instead, and therefore they do not need a special pointing device.\n",
"BULLET::::- Display: 3.2 inch (8.1 cm) thin-film transis... |
how do birds find new bird feeders so quickly when there was never a bird feeder remotely close to that before? | Birds are hunters and foragers and are pretty observant. Crows can remember people and will give warning calls if they see a person who they feel threatened by. The local birds in your neighborhood probably watch the goings ons quite a bit and of course will take note when they see someone put up a feeder. | [
"A birdfeeder, bird feeder, bird table, or tray feeder are devices placed outdoors to supply bird food to birds (bird feeding). The success of a bird feeder in attracting birds depends upon its placement and the kinds of foods offered, as different species have different preferences.\n",
"Flocks of birds often ex... |
Why was New England so different from the Chesapeake region? | Complicated answer, but the short of it is the type of people that immigrated to New England vs the rest of the United States ( and the rest of 13 colonies were similar to Virginia not to NE). The communities that tended to be settled in New England tended to come from England as a unit, and when they arrived in New England tended to recreate their village-community setting. Hence the name New England, for its similarity to old England. For a in-depth answer see Jack Greene's *The Social Development of Early Modern British Colonies and the Formation of American Culture*. | [
"The New England Colonies were located along the Atlantic coast where there was an abundance of marketable sea life. Excellent harbors and some inland waterways offered protection for ships and were also valuable for fresh water fishing. By the end of the 17th century, New England colonists had created an Atlantic ... |
why does the body store fat (or so much of it) if we can not realistically live off what the fat cells provide, why not have a cut off point? | Too much body fat was never a health concern for 99.999% of human existence. It is only a concern now because of how much food we have access to and the sedentary life the modern world has made.
Evolution only kicks in to traits that affect reproduction or survivability *until reproduction*. Evolution does not made things "better" for us, or make things more ideal. | [
"However, other subcutaneous fat tissues also might contribute to metabolic disease, if the fat cells become too enlarged and \"sick.\" Admittedly, subcutaneous fat cells typically are larger, and capable of storing more fat when needed. However, subcutaneous fat tissue represents the largest proportion of fat tiss... |
How do we know if someone really has synesthesia? | According to my textbook, *Psychological Science Fourth Edition* by Gazzinga, an experiment by Ramachandran and Hubbard (2003) used [this](_URL_0_) to test for synesthesia. People with a certain type of synesthesia can pick out the 2's in the picture significantly faster than those without, which is evidence that they perceive the 2's unusually differently than the 5's. | [
"Synesthesia can occur between nearly any two senses or perceptual modes, and at least one synesthete, Solomon Shereshevsky, experienced synesthesia that linked all five senses. Types of synesthesia are indicated by using the notation x → y, where x is the \"inducer\" or trigger experience, and y is the \"concurren... |
do hydrogen bombs cause fallout? | So, the way that thermonuclear bombs (h-bombs) work in general is something like this. You have a typical nuclear device composed of your favorite fission bomb (uranium or plutonium), and then you've got your fusion material. Encasing the fusion material is often a uranium shell, too, to help the fusion occur.
You've probably noticed that there are lots of things in h-bombs that aren't h. These things do leave fallout. | [
"BULLET::::- During the Castle Bravo test of the first deployable hydrogen bomb, a miscalculation resulted in the explosion being over twice as large as predicted, with a total explosive force of . Of the total yield, were from fission of the natural uranium tamper, but those fission reactions were quite dirty, pro... |
in an accident, what is the paperwork, and steps that i should take if i get rear-ended, or if i hit someone else? | DO NOT ADMIT GUILT! Do not say anything that could be implied as an admission of guilt. Your insurance company should have instructions somewhere in the paperwork on what to do, and what not to do. | [
"Anyone who has caused a traffic crash, or contributed to it, has the duty to identify themselves to the victims or to other contributors. If the victim is not present (such as in the case of damage of a parked car) the one who caused the crash has to wait a certain time. If the victim does not appear, he has to re... |
why do scam emails ask people to use western union for transferring funds? | Western Union's wire transfers are often non-reversible. That means that if you send money via Western Union, and it goes to the person you sent it to, you can't get your money back, even if you learn that the recipient was cheating you.
Western Union is also often involved in scams from the other side, because it can take up to several days for its money orders to be processed. So if you try to sell something on Craigslist, scammers will offer to buy it, then send you a Western Union money order for more than the price. (They will tell you some lie about why this implausible error has been made.) They will then ask you to send change, again via Western Union. By the time you realize the first money order was a forgery, your own money will have been sent, received, and vanished. | [
"One of the largest companies that offer wire transfer is Western Union, which allows individuals to transfer or receive money without an account with Western Union or any financial institution. Concern and controversy about Western Union transfers have increased in recent years, because of the increased monitoring... |
If I was to travel back to 12th century England, would we be able to easily understand each other's use of the English Language? | No, you would not be able to understand the language nor would you be understood. You would be hearing Middle English, and early Middle English at that (as the transition between Old English and Middle English happens around the 11th century). You might hear a word here or there, but the majority of the language would be incomprehensible.
For an example of a 12th Century work in Middle English, you would look at *The Ormulum,* a biblical interpretation by Orm, an English monk.
_URL_3_
To hear how it sounds, this is one of the few audio links I could find of *The Ormulum:*
_URL_2_
This presents a good image of English pronunciation following a major phonetic shift post-Norman conquest of England
For an example of how the English language developed from the 12th Century, take a look at Chaucer's *The Canterbury Tales,* written in the late 14th century:
_URL_4_
This represents two hundred years more development toward Early Modern English (Shakespeare's plays) than the 12th century would. It is a bit more comprehensible than *The Ormulum,* and we can begin to hear (and see) the shift toward Early Modern English.
Here is a reading of the prologue of Chaucer's *The Canterbury Tales* for comparison:
_URL_1_
Moreover, if you want to progress into Early Modern English (Shakespearean English), you may be surprised to find that the pronunciation is not what you expect as well. As a bonus, here's a video from a Shakespearean scholar explaining the difference between Shakespeare's pronunciation and modern pronunciation:
_URL_0_
As you can hear, the original Shakespearean pronunciation is a direct phonetic descendant of what we hear in *The Canterbury Tales.*
| [
"First spoken in early medieval England, the English language is the \"de facto\" official language of the UK, and is spoken monolingually by an estimated 95% of the British population. Seven other languages are recognised by the UK Government under the European Charter for Regional or Minority Languages – Welsh, S... |
The negative portraying of Persian empires are usually from Greek sources. But then how about the portraying of the Greek states and their people in Persian sources? Why we never heard about those? | You never hear about Persian sources because they no longer exist. Virtually nothing survives from the Achaemenid written corpus, due in part to the destruction of major collection sites like Susa and Persepolis. We have the royal inscriptions, especially of Darius I and Xerxes (which are mostly in the Louvre, now), but that is all. | [
"In the 5th century, the Achaemenid Empire of Persia began a series of invasions against Ancient Greece. Because of this, some scholars believe that on most 5th-century Greek art, the Persians were shown allegorically, through the figure of centaurs and Amazons.\n",
"Western art, no less than history and theology... |
why a coffee creamer that contains milk products is allowed to be called "non-dairy." | When foods characterized on the label as 'nondairy' contain a caseinate ingredient, the caseinate ingredient shall be followed by a parenthetical statement identifying its source. For example, if the manufacturer uses the term 'nondairy' on a creamer that contains sodium caseinate, it shall include a parenthetical term such as 'a milk derivative' after the listing of sodium caseinate in the ingredient list.
They can list it as nondairy so long as they basically add fine print stating it has milk products in it. Same can be done with vegetarian foods and lots of other things. Pretty much a loop hole. | [
"A milkette, (also referred to as dairy milker, creamette or creamers) is a single serving of milk (2%) or cream (10% and 18%) in or containers used for coffee and tea. They are a common condiment at coffee shops, cafeterias and on airlines in Canada and the United States.\n",
"Non-dairy creamers, commonly called... |
congratulations explain like i'm five on 250,000 subscribers! | Congratulations! I've lurked this subreddit for months, even though I've never posted here, and I've always been impressed by the quality of responses here. I personally think this should be one of the default subreddits, but still an amazing community nontheless. | [
"Telemiracle 31 (2007), the first telethon to exceed the $5,000,000 pledge total, broke all previous records, with an official final total of $5,604,682. This record was broken in 2012 (Telemiracle 36) with a final total of $5,906,229. This record was once again broken on March 4, 2018 (Telemiracle 42) with a final... |
what do coders, programmers, and software developers do at big name companies like twitter, facebook, apple, etc all day. why are they in need and do they work round the clock. would apps survive if work discontinued? | > ELI5: What do coders, programmers, and software developers do at big name companies like Twitter, Facebook, Apple, etc all day.
They work at maintenance (bug-fixing, data-"fixing etc.) and new features for the companies software.
> Why are they in need
Because programs have bugs. Which, for example, might also lead to the corruption of the users data.
> and do they work round the clock.
Yes, because those companies typically have departments on several continents. So you can get round-the-clock coverage while having most people work at normal office hours. A programmer at the east coast would come to work for example at have e-mails, tickets etc. from India on his computer. And when he leaves, his work is beeing continued at another location.
> Would apps survive if work discontinued?
They would stay at the current state. Depending on the app tehy would stop working someday because, for example, there's a new generation of smartphones and the code for the facebook app would need changes to work on these devices.
Plus, if you don't add new features but the competition does, people will sooner or later use their apps. | [
"Most software engineers work as employees or contractors. Software engineers work with businesses, government agencies (civilian or military), and non-profit organizations. Some software engineers work on their own as consulting software engineers. Some organizations have specialists to perform all of the tasks in... |
planned obsolescence, what is it? | you come up with a complete product: take 5 features from it. every year you can release a new version with a new feature and sell 5x the products, while making your old product look old and dated (even though its only a year old)
there is also another side to this: you can develop a product that can only be expected to work well for a short amount of time (~2-3 years) so that everyone who buys your product is forced to buy a new one when theirs becomes so worn it no longer fulfills its function.
aka: apple | [
"Planned obsolescence, or built-in obsolescence, in industrial design and economics is a policy of planning or designing a product with an artificially limited useful life, so that it becomes obsolete (i.e., unfashionable, or no longer functional) after a certain period of time. The rationale behind this strategy i... |
marijuana solves social anxiety for me. how exactly does that work? | Everyone who's smoked marijuana knows how it ruins your memory. It is thought that this is the reason for all the good stuff. You don't remember exactly how things taste or feel, which leads to the novelty of eating ice cream and having sex. Likewise, you forget how you're supposed to act, and how you think other people are judging you. Of course, if you are not reacting well with the marijuana this can all backfire and result in paranoia, but that's one theory. | [
"Numerous studies have been conducted regarding anxiety and cannabis for therapeutic purposes, and these cross-sectional studies have been mostly consistent regarding the anxiolytic effects. The studies showed relief of anxiety as a result of cannabis consumption.\n",
"People sometimes use cannabis to cope with t... |
why is fifa so against using technology in football? | Football is one of the fastest games out there. The clock doesn't stop, there is only one break, and if the ball goes out of play it comes straight back in again.
Technology is seen as interrupting the flow of the game and causing stoppages. Many believe that it is the speed and intensity that the game is played at that makes it so great and therefore do not like technology being introduced.
The English Premier League has introduced goal line technology, however, and in a way that does little to affect the game. The ball may have crossed the line, the referee looks at his watch which will instantly tell him, if the ball didn't cross the line then play continues. | [
"Other critics believe it would be prohibitively expensive to implement the technology at all levels of the game and particularly for smaller/poorer football associations. FIFA officials have expressed a preference for 'better refereeing' as well as more match officials over implementing the technology.\n",
"Whil... |
AskScience AMA Series- IAMA graduate student working with human papillomavirus (HPV) | How exactly does a virus cause cancer? Does it insert some kind of anti-apoptosis gene in the host cell?
Can it infect and/or cancerize any other organs? | [
"HPV (Human papillomavirus) is the most common STI among teens (as well as adults). In a CDC study, 18% of teen girls were infected with HPV. Another study found that HPV infections account for about half of STIs detected among 15- to 24-year-olds each year. While HPV infections may not cause any disease and is oft... |
What knowledge of electricity did Japan gain from the Dutch? If it was substantial, and the technology was sound, why was it not put to any practical use? | Japanese scholars actually did make practical use and study of the electrical machinery brought to Japan by the Dutch. However, this early form of technology was very limited in its applications, and the progress they made in their studies was superseded within a few decades by more modern technology and science from the West. So, Edo Period electrical research is just an interesting side story in scientific history, not the beginning of something greater.
The bit of electrical know-how that the Dutch brought to Japan was a variation on [the Leyden jar](_URL_3_): a set up that stores a static electric charge which can be then discharged at will. The Leyden jar was invented in 1745 in the Netherlands, and the concept had undergone a bunch of development in Europe. Some time around the late 1760s, the Dutch East Indian Company shipped one of the latest electrical machines to Nagasaki as a gift for the shogun. It arrived broken, and no one knew how to fix it. One of the shogunate's translators at Nagasaki, Zenzaburou Nishizaki, bought or was given the broken machine. He in turn sold it in 1771 to Hiraga Gennai, a polymath inventor/painter/naturalist/writer/researcher who was interested in everything.
Gennai today has a popular reputation in Japan something like Leonardo da Vinci in the West, in manga/anime/movies/novels/games, he's the mad inventor who can fiddle around with a few tools and make you a rocket ship out of spare parts. The legend is based on some real accomplishments, particularly his work on the electric machine, which he called the Elekitel (or as transcribed phonetically, the *erekiteru*.) It took six years and some consultation with a member of the Dutch embassy to the shogun to figure out how the machine worked, but once he did, he was able to build his own version. Gennai’s machine became a marvel. His version of the machine worked by “rubbing an insulated cylinder of glass (a commodity imported from the west at the time) against a piece of foil to produce a static charge.” (p. 84 “[Hiraga Gennai: Tokugawa Japan’s Creative Genius as Author](_URL_1_)” in *Virginia Review of Asian Studies* by Christopher Smith, 2009.)
In 1795, Tachibana Nankei wrote a description of Gennai’s version of the machine.
> The device called an erekiteru came to Japan twenty-three years ago. It is a machine for drawing fire from a person's body. Wheels are set within a box; it is just under an metre and an iron chain, five or six metres in length and ending in a looped handle, leads off. You have someone grasp the handle and then start the wheels rotating, so that power is transmitted along the chain. This provokes a reaction in the person, and little bits of paper brought up to them will move and dance of their own accord; if someone brings their hand close, you can hear a sound like spitting fat, and see a flame flying out. No-one who has yet to see the amazingness of this device will believe in it.
- Quoted p. 84, Smith
[A photo of a reproduction of the machine](_URL_0_).
Gennai made ten copies of his machine, and mostly used them for electrotherapy. The shock numbed areas of pain. However, Hiraga Gennai’s career ended in tragedy. His greatest patron lost his influence in the shogunate, then Gennai began to show signs of mental illness, at last murdering one of his students in what seems to have been an episode of pyschosis. Gennai died in prison in 1780, and as a result, his work wasn’t directly passed on. Other scholars had to derive the principles from the machines themselves, but by 1787, one of them: Morishima Chuuryou had published a complete design of the machine. He and others manufactured the machines for both electrotherapy and display as curiosities.
The first scholar after that to do scientific research with the machine was Hashimoto Soukichi (1736-1836). He’d read Western research on the matter, including a Dutch translation of some of Ben Frankin’s writings. He improved the design of the Elekitel, and recreated Western experiments with electricity. Most vividly, he got one hundred children from a nearby school to hold hands so he could send an electric shock through them.
Another researcher, Kawamoto Koumin (1810-1871) started work in the 1830s on understanding and using electricity. Working with outdated texts from the West, Kawamoto was discovering concepts already known in Europe, so his development of a voltaic pile didn’t change history, but shows how busy Japanese scholars were in developing uses for electricity.
With the opening of Japan to full commerce with the West, Japanese scholars were able to fully enter the mainstream of science. In the last days of the shogunate, however, there was one man who used the previous research to absolutely churn out practical inventions. Sakuma Shouzan is best known as a political and military theorist (and assassination victim), but he was also an inventor.
> He fabricated silk-covered wire and created a telegraph apparatus in about 1850 or 1860 for communication experiments in his home town of Matsushiro (until quite recently, his experiments were dated to 1849, but now most investigators believe that they occurred after 1860). Sakuma also fabricated other devices, such as earthquake prediction apparatus and medical equipment. In his medical equipment, Sakuma made use of Faraday’s law of electromagnetic induction to generate a high voltage by an induction coil, and used it instead of the static charge of the Elekitel. (p. 6 in "Formation of Electrical Machinery Technology in the Edo Period of Japan")
That quote is from a seven-page article on this exact subject that so *exactly* fits what you're interested in that I'm very annoyed it's behind a paywall. I've gone over some of the highlights they mentioned, as well as added some background on Hiraga Gennai, but in the off-chance, you have library access,
- Inui, A., Yamamoto, M. and Kawaguchi, Y. (2015), [Formation of Electrical Machinery Technology in the Edo Period of Japan](_URL_2_). Electr Eng Jpn, 193: 1–7. doi:10.1002/eej.22759
is available in the Wiley Online Library, as linked. | [
"The Dutch also engaged in piracy and naval combat to weaken Portuguese and Spanish shipping in the Pacific, and ultimately became the only westerners to be allowed access to Japan from the small enclave of Dejima after 1638 and for the next two centuries.\n",
"The Dutch also engaged in piracy and naval combat to... |
Tetris was made in the USSR in 1984. How can a video game from the Soviet Union become so popular amidst a government known for censorship? Did this mean that the Soviet Union had a video game industry? | I'm not sure I completely understand you. Are you implying that the Soviet leadership would have been opposed to video games?
Personally, I'm not certain about that at all. | [
"History of mass videogaming in Russia (back then USSR) takes its roots in the early 1980s when personal computers of different models (Atari 400/800, Commodore 64, ZX Spectrum 48/128) were brought to the country from United States, Europe, Japan and China. At the same time, a local company, Electronica, released a... |
Is there a method to remembering dates/locations? | Honestly, dates aren't *that* important. Yeah, they're good to have in a paper, but you could easily look them up.
I think the most important things is to be able to place it in context. Is it the end of the world if you don't remember that Vicksburg fell on July 4, 1863? No. But you should know that it did happen the day after Gettysburg and its overall affect on the war.
What day did Columbus leave Europe in 1492? Who really cares. Just know that it happened the same year that Spain expelled all of the Jews out of their country and finished the *Reconquista.* | [
"The stratigraphy of an archaeological site can be used to date, or refine the date, of particular activities (\"contexts\") on that site. For example, if a context is sealed between two other contexts of known date, it can be inferred that the middle context must date to between those dates.\n",
"If we know the ... |
why there was a 'leap second' added to the end of 2016? | the rotation of the earth is not a constant. in fact the rotation of the earth is slowing down, which means that a full day is getting slightly longer. without leap seconds our clocks would slowly drift ever so slightly out of sync with the actual day. we could deal with this by redefining how how long 1 second is, making it slightly longer so that one day is still exactly 24*60*60 seconds. but in practice that is really inconvenient for a lot of our technology which relies on very precise timing. its easier to just move us ahead one second every couple of years or so. | [
"A leap second is a one-second adjustment that is occasionally applied to civil time to keep Coordinated Universal Time (UTC) close to the mean solar time at 0 Meridian, Greenwich, to accommodate irregularities and long-term slowdown in the Earth's rotation. UTC was introduced on January 1, 1972, initially with a 1... |
Is sunlight antibacterial? | Yes, and antiviral. It's nowhere near as effective as UV lamps, which may take only 15 minutes or so to sanitize an area, but UV purification of bottled water for example is possible after 2 days of exposure to sunlight ( assuming non turbid water). Lots of factors come into play such as latitude,season and so on so it's not something you'd ever want to rely on unless you were desperate. Historically there were instances of cell biologists leaving cell cultures or plates outside for like 10 minutes or so to get better odds of finding a desired mutant. There's much more effective and reliable means of mutagenesis now though. | [
"Ultraviolet light from the Sun has antiseptic properties and can be used to sanitize tools and water. It also causes sunburn, and has other biological effects such as the production of vitamin D and sun tanning. Ultraviolet light is strongly attenuated by Earth's ozone layer, so that the amount of UV varies greatl... |
how does pseudorandom works? | True randomness isn't possible for a processor, since it's always just running input - > some function - > output. But there are functions that behave 'almost randomly'. A (bad, but easy to understand) example is the following method for generating a random 5-digit number:
* Start with any 5-digit number. Let's say 12345.
* Square it. 12345^2 = 152399025
* Take the middle 5 digits: 15**23990**25
* Our next 'random' number is 23990.
Then to generate another one, we repeat the process. Our next number in this case would be 55201, then 71504, 28220, etc.
Now, this turns out to be a bad example, because it will always collapse down to a cycle or a repeated number at some point. But there are more mathematically-sophisticated methods that are better behaved. | [
"A pseudorandom variable is a variable which is created by a deterministic algorithm, often a computer program or subroutine, which in most cases takes random bits as input. The pseudorandom string will typically be longer than the original random string, but less random (less entropic in the information theory sen... |
is the Geiger counter not an observer in the Schrödinger's cat experiment? | Yes. That is exactly the point of the thought experiment. Schrodinger was trying to point out how silly it was to talk about 'Observers collapsing the wavefunction' in quantum mechanics, when it is much more useful to talk about 'measurements collapsing the wave function'. If a human observer were required in order to collapse the wavefunction, then you could set up an experiment where a cat is both alive and dead at the same time, which is obviously absurd. | [
"A more precise confirmation of the relativistic Doppler effect was achieved by the Mössbauer rotor experiments. From a source in the middle of a rotating disk, gamma rays are sent to an absorber at the rim (in some variations this scheme was reversed), and a stationary counter was placed beyond the absorber. Accor... |
Why are single-poled magnets physically impossible? | As others have said, magnetic monopoles are not physically impossible, just unobserved. What is worth knowing is not only are they physically possible, they are a natural consequence of most grand unified theories that combine the electromagnetic, weak, and strong forces into a single over-arching force. Thus, there is actually some reason to expect that there are monopoles.
Does it make sense for them to exist and for us not to have seen them? Actually, the answer is yes. If grand unification is correct, monopoles would have formed in the extremely early universe (grand unified monopoles are very, very massive -- 10^(15) proton masses or more), but then inflation would expand the universe so much that the monopoles would be diluted, so that there would be around one monopole only in the entire observable universe.
Dirac observed back in 1931 that the existence of magnetic monopoles would explain electric charge quantization (that every particle's electric charge is an integral multiple of some basic unit charge). Interestingly, grand unification explains charge quantization as well on grounds separate from the presence of monopoles -- but magnetic monopoles appear, too, which would provide a second line of argument. | [
"Permanent magnets make their own magnetic field. An example of a material from which a permanent magnet can be made is iron. It has a north and south pole, and cannot be split into a monopole — in other words, a north pole does not exist without a south pole.\n",
"Magnetos have advantages of simplicity and relia... |
how do some animals get enough nutrients to survive by only eat bugs or grass? | Most animals that eat grass or other low calorie/nutrient foods spend a huge portion of their day simply eating. Cows graze all day, the amount of food they intake is massive. It usually comes down to quantity over quality. | [
"They eat primarily leaves, but also shoots, fruits, nuts, berries, bark, some native flowers, and even some small vertebrates. In addition, when they cannot find food, they have been known to eat the algae that grow on their fur for nutrients. They have large stomachs, with multiple chambers, which help to ferment... |
what are the long term effects of lsd use? | Calmness and an overall deeper understanding of life and the beauty of existence. | [
"Some controversial case reports suggest that ingesting tryptamines such as LSD, psilocybin (as found in hallucinogenic mushrooms), or DMT can reduce pain and interrupt cluster headache cycles. A 2006 survey of 53 individuals found people said that psilocybin extended remission periods in 18 of 19. The survey was n... |
how to some dogs instantly hate each other at first sight and some love each other, even though they've never met before? | Just as there are manners with humans, there are manners dogs. Just like humans, some dogs don't understand these manners.
They're little things people often don't notice. They aren't supposed to look other dogs straight in the eye at first meeting. It's rude, just like staring a stranger down would be.
When dogs are in another's territory, they are supposed to submit to a good ass sniffing. This is how dogs recognize each other so it's a way of meeting/greeting. Failure to do so could result in hostility
It's little things like that. We often times see them as fighting, but sometimes it is just in their manners. | [
"Human–canine bonding is the relationship between dogs and humans. This bond can be traced back at least 15,000 to 30,000 years ago to the Bonn-Oberkassel dog that was found buried with two humans. In the United States, over 48% of households have a pet dog. For centuries, dogs have been labeled as \"man's best fri... |
How come metals doesn't sublimes in very low pressures? | One of my professors once told me "to an engineer, there's no such thing as zero, only 'small enough'". This is actually the exact thing he used as an example for his little rule. Metals will exhibit a vapor pressure and sublimate, but that pressure is extremely small, which means it happens so slowly as to be nearly immeasurable.
Incidentally, a much more noticeable effect is the phenomenon of "out gassing". This is when other elements dissolved in the metal diffuse out of it and into the vaccuum, common examples being Oxygen and Hydrogen (among others of course). Out gassing is a major problem for people working with vacuum chambers, since these gasses make your vaccuum less perfect when they are expelled to the inside of the chamber. A common technique is to "bake" the chamber by heating it for several hours while evacuated, which actually speeds up out gassing and (hopefully) causes the majority of the gasses to be expelled from the metal and removed slowly by the vaccuum pump, so that subsequent uses of the chamber experience less out gassing. Coating the inside of the chamber with Tungsten or Titanium, which hold onto some gasses very strongly can also help. | [
"Frequencies in the range of 10–100 MHz are necessary to cause dielectric heating, although higher frequencies work equally well or better, and in some materials (especially liquids) lower frequencies also have significant heating effects, often due to more unusual mechanisms. For example, in conductive liquids suc... |
what do the dilation drops actually do to your eyes and why does it make your eyes sensitive to light? | Dilation drops open up your pupils, much like they would naturally do in the dark, to allow more light in. Helps the doctor see better when he's examining your eyes. Going outside while your pupils are dilated hurts because your pupils are already open and they can't retract like they would normally, so the light is POURING into your eyes. Tried to explain that as best as possible. | [
"BULLET::::- Pupil dilation - Pupil dilation may be harder to detect by most people. Sexual desire may be a cause of such dilation. It may also be an indication of attraction. Physiologically, eyes dilate when it is darker to let in more light.\n",
"The uncus can squeeze the oculomotor nerve (a.k.a. CN III), whic... |
Is there anything in nature which can be considered as being infinite? | We *consider* the universe to be infinite in size (thus infinite stars, infinite galaxies, planets, etc.{No, this does not imply that there must be copies of Earth out there}). We *cannot show* that it is such, but the data is reasonably suggestive of this case. | [
"If we [...] define Being in the universal sense as the principle of manifestation, and at the same time as comprising in itself the totality of possibilities of all manifestation, we must say that Being is not infinite because it does not coincide with total Possibility; and all the more so because Being, as the p... |
Do anti-particles produce anti-gravity? If not, what about with virtual particles? | I guess I will take a first crack at this question.
Though it hasn't been experimentally verified, current thinking would have that anti-particles have attractive gravity, just like regular particles. All matter with positive energy sources gravity in the same manner, and anti-particles have positive energy.
The question about virtual particles is more complicated. Consider "empty" space, which actually experiences quantum fluctuations that generate virtual particle pairs. This empty space in fact is possessed of a certain amount of "vacuum energy" due to these fluctuations. It is an open question in physics as to just how much energy is there and how it sources gravity.
Naively, there should be an awful lot of vacuum energy out there, so much that it should dominate the evolution of our universe (it turns out that vacuum energy has negative pressure, which results in a sort of anti-gravity that causes the universe to expand). This is not what we observe. We do observe that the universe is filled with a form of energy, known as dark energy, which has the right properties to be vacuum energy, but there is far too little of it (by something like 10^120). In fact a more accurate assumption would be that the vacuum energy has no gravitational effect at all, or is somehow cancelled out. This could be wrong, since we do see the influence of dark energy in our universe, but its a better starting place than the naive guess (which is off by 10^120). | [
"It is difficult to directly observe gravitational forces at the particle level. For charged particles, the electromagnetic force overwhelms the much weaker gravitational interaction. Even antiparticles in neutral antimatter, such as antihydrogen, must be kept separate from their counterparts in the matter that for... |
Can dogs or cats catch a cold virus or the flu from humans? | No. It's very unlikely. Viruses tend to be species-specific, with a couple of exceptions.
I'm not entirely sure about the specifics of feline respiratory viruses like influenza, however I can answer this question using FIV (feline immunodeficiency virus) - the cat version of HIV (human immunodeficiency virus).
In HIV, the virus first binds to a receptor called CD4, which is found on the surface of cells of the immune system, particularly T-helper cells. It then associates with a co-receptor (usually CXCR4) and this facilitates its entry inside the cell, where it can start to work.
In the feline version, FIV, the virus binds to CD134 - a receptor found in abundance on activated feline lymphocytes (a type of immune cell). In the same manner as HIV, it then binds to the CXCR4 co-receptor and enters the cell. It's worth noting that some other animals in the cat family (particularly cheetahs and lions) are also susceptible to FIV because they share genetic similarity.
FIV cannot affect humans because our CD134 is a completely different shape to a cat's CD134. Likewise, our CD4 is probably very different to cat CD4. Therefore, viruses from one species cannot usually affect another because they simply cannot recognise the components they need to get inside the cell. This is the case for respiratory viruses like colds and flu too: the virus cant get into the cat's respiratory cells and thus cannot work.
Viruses can, and do, jump species through mutation though. Don't have time to explain but there's a [good basic explanation over on wikipedia](_URL_0_)
Hope that helps :) | [
"The virus has also adapted to grow in cells of cold-blooded vertebrates. Most animals can be infected by the virus and can transmit the disease to humans. Infected bats, monkeys, raccoons, foxes, skunks, cattle, wolves, coyotes, dogs, cats, and mongooses (normally either the small Asian mongoose or the yellow mong... |
How far can the Earth actually move towards or away from the Sun and still be okay? | This is referred to informally as the [Goldilocks](_URL_0_) zone after the fable. It extends inward for our solar system to about Venus and extends past Mars.
While such drastic orbital changes would undoubtedly wreck our climate, these represents the regions where it's plausible to find a temperate planet. It's speculated that Mars for instance was vastly more Earth like in it's early history, but it failed due to it's small mass and the solidification of its core. | [
"Planetary scientists have considered moving the Earth farther away from the sun as the solar luminosity increases over the next billion years. Various mechanisms have been proposed to increase the size of the Earth's orbit.\n",
"Earth orbits the Sun at an average distance of about every 365.2564 mean solar days,... |
how can car manufacturers seemingly copy features and ideas from each other without getting sued? | You can only sue for stuff like this if you have a patent. Either the originator of the feature put it directly into public domain, the patent was denied, or they are giving the other companies permission to use the feature. It's also good to know that many many makes of vehicles are all owned by a single company, so they can freely use their own stuff. | [
"The judge also accepted in whole the defendant’s argument that cars of the same segment cannot avoid a certain level of resemblance due to technical restrictions, similar purposes and goals, especially when it comes to such small cars that present a challenge to design. The ruling concludes that “there is no compe... |
explain radiation, radioactive material, and isotopes to me. literally like i'm 5. | Basically, atomic nuclei are made up of protons and neutrons. The number of protons determines the chemistry of the resulting atom (1 proton is hydrogen, 2 is helium, 3 is lithium, etc.). Nuclei can also have neutrons which, for the most part, don't effect their chemistry but can make atoms more/less stable. 2 nuclei with the same number of protons but different numbers of neutrons are referred to as different isotopes of that element.
For example, Carbon (6 protons) with no neutrons basically cannot exist. Most Carbon on Earth exists as C12 (6 protons, 6 neutrons) but with some trace amounts of isotopes like C13 (6 protons, 7 neutrons) and C14 (6 protons, 8 neutrons).
Some combinations of protons and neutrons are very stable, while other combinations are unstable and cause the nucleus to eventually break apart. These unstable isotopes are what are known as radioactive materials. When they break apart, radioactive materials tend to give off a lot of harmful stuff like high energy light (gamma rays) which can damage your DNA among other things. | [
"A radioactive source is a known quantity of a radionuclide which emits ionizing radiation; typically one or more of the radiation types gamma rays, alpha particles, beta particles, and neutron radiation.\n",
"Radiation is used to determine the composition of materials in a process called neutron activation analy... |
How much did WW1, and particualry the Galipoli campaign, influence Australian views on the Britsh Empire? | Okay. This is just a little bit *after* my period. But, I'm an Aussie, and I know something about this.
Basically, Gallipoli didn't do much to change Australians' general views on being in the Empire. We were gung-ho Brits before, and gung-ho Brits after. There was some grumbling about using Aussie troops as cannon fodder, and definite complaints about the incompetence of generals' sending troops to take an untakeable military outpost. But, those complaints were specifically about the running of the war, not about participation in the Empire.
We willingly sent 10% of our population to fight in that European war, like the good British subjects we were.
As our Prime Minister, Joseph Cook, [said at the time](_URL_0_):
> whatever happens Australia is a part of the Empire right to the full. Remember that when the Empire is at war, so is Australia at war.
The then Opposition Leader (and former P.M., and P.M.-to-be), Andrew Fisher, also famously declared:
> Australians will stand beside our own [the British] to help and defend her to our last man and our last shilling.
We'd had inklings before this that Australia's and Britain's interests weren't always aligned, such as regarding the New Hebrides islands (now Vanuatu) in the 1880s. There was a fear in the Australian colonies, particularly Victoria, that these islands would be given by the British to the French, as part of some European politicking. The Australians (again, particularly the Victorians) saw that they had an interest in what was happening on their own doorstep, and were prepared to take action to ensure that these nearby islands did *not* become French property. Luckily, the crisis passed without such action being required. However, Alfred Deakin wrote about this afterward:
> It was therefore decided to forestall [the French plans to seize the islands] by despatching a detachment of the Victorian permanent military forces in a swift steamer with orders to hoist the British flag and keep it flying. [...] Taking into account the electrical conditions which then obtained, this decisive action might have had the gravest consequences. It must at least have forced the hands of the British Government to some extent, if indeed it did not provoke a final settlement of the vexed question. At this time Australians had grown tired of appealling and protesting and were determined to act for themselves on behalf of the Empire should the necessity arise. [The Federation Story, pp.22-23]
So, there was always a slight tension between Australians and the British, but we still considered ourselves Britons in exile.
Our attitudes about being British didn't really change significantly until WWII. One turning point was when the Japanese bombed an Australian city (the first and last time that war happened on Australian territory). The British were otherwise occupied, and couldn't help.
It's notable that Robert Menzies, our Prime Minister during the 1950s and most of the 1960s, was a devoted Anglophile and was infatuated by the young Queen Elizabeth. At the start of his tenure, he represented the majority Australian opinion in this regard. By his second decade in the office, this attitude was seen as old-fashioned. We'd grown up: we were now *Australians*, not Britons down under.
| [
"After the war, the bad conditions and high casualties amongst the Anzac troops resulted in a reasonably prevalent view in Australia that these had been due to the incompetence of British officers commanding the Australian troops and their disregard for the casualties that resulted from poorly planned or ill-concei... |
why does the colour black go with any other colour? | Black is zero. When you mix something with black, you are essentially mixing it with the darkest possible shade of itself, and shades of the same color tend to work together. | [
"The colours have different meanings, the black is for the African ancestry of the people, the blue for hope, the red for energy or life of the people. The successive colouring of yellow, blue, and white (from the sun down) also stands for the sun, sea, and sand. The blue also represents the Caribbean Sea, and the ... |
When did the kings stop being warriors and stop fighting on the front like Richard lion heart and Henry V? | Monarchy has gone out of fashion but there are still plenty of heads of state who come from the military and lead it directly. As recently as World War I you have Tsar Nicholas II symbolically leading the army at the front. In theory the President of the United States could do the same thing, though I believe the only one to exercise that power was George Washington, during the Whiskey Rebellion.
Sure, the intensity of warfare has made heads of state stay further and further away from the battlefield lest they end up like James II of Scotland. But that doesn't mean there aren't plenty who have experienced combat in their lives, which would make them warriors, or that they don't still take direct command. | [
"Henry's successor, Richard I \"the Lion Heart\" (also known as \"The absent king\"), was preoccupied with foreign wars, taking part in the Third Crusade, being captured while returning and pledging fealty to the Holy Roman Empire as part of his ransom, and defending his French territories against Philip II of Fran... |
Between 1945-1989 when colonial powers began to lose their grip on their overseas territories was there an communist style government in Africa. | There were quite a lot of communist governments in Africa actually. Angola and Mozambique both had civil wars in which a Western- (and SA-backed) rebel army attempted to overthrow their respective Communist Soviet-backed governments. Other communist countries included Benin (overthrown by a popular uprising), Congo-Brazzaville, Somalia and Ethiopia, the latter of which was a particularly repressive Communist regime led by the military leader Mengistu Haile Mariam, who committed genocide against his own people and was at least partly responsible for the Ethiopian famine of 1984 (ie the one that Band Aid made famous).
As for left-wing African leaders who weren't officially 'Communist', a good example is Julius Nyerere, the first president of Tanzania. He was a proponent of 'African Socialism' and the concept of *Ujamaa*, a form of communal socialist empowerment. One of his main goals was the creation of farming communes under the *Ujamaa* model, and under Operation Vijiji, Nyerere attempted to forcibly relocate the whole of Tanzania's rural population to these communes, with very limited success. | [
"The possible emergence of an African communist state remained a source of disquiet in the West. In February, the British Defence and Overseas Policy Committee said that, while British commercial interests in Zanzibar were \"minute\" and the revolution by itself was \"not important\", the possibility of interventio... |
how is it that many american republicans are strongly against the iran nuclear deal, when it is a shining example of good democracy in european countries? | They are opposed to it for two main reasons--they do not think that Iran will honor the deal in the long run, and secondly, they want to maintain sanctions because Iran is a dictatorial state and seen as a sponsor of international terror. A lot of the rhetoric suggests a lax policy toward Iran is being irresponsible toward Israel, an American ally. | [
"Although the US overcame Russian attempts to block a UN security council discussion of the Iranian protests, it lost European support to act against Iran. While the UK, France and Germany agreed with the US on protection of protesters' rights, they used the debate to reject American efforts to undermine the nuclea... |
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