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When fish take out oxygen from water, do they leave behind hydrogen? Or how does that work? | Fish take oxygen (O2) that is *[dissolved in the water](_URL_1_)*, not the oxygen from the water (H2O) molecule.
Further, taking out oxygen from water is a chemical reaction, not a nuclear one. While it takes a lot more energy than filtering out oxygen gas from water, [you can do it with a battery](_URL_0_) instead of a nuclear reactor. | [
"Laboratory tests conducted by fish culturists in recent years have demonstrated that common household hydrogen peroxide can be used safely to provide oxygen for small fish. The hydrogen peroxide releases oxygen by decomposition when it is exposed to catalysts such as manganese dioxide.\n",
"Dissolved oxygen (DO)... |
Why did soldiers in the Civil War assume aliases? | I haven't read much about the use of aliases during the American Civil War, but something called "bounty jumping" was indeed a practice people engaged in, and this would likely involve the use of an alias. So during the war, one could earn a bonus for voluntarily enlisting in the army (the idea being that you might get drafted anyway, so you might as well sign up, and earn the bonus you'd miss out on if drafted). Some enterprising individuals took advantage of this practice by enlisting in a unit, collecting their enlistment bounty, then deserting to do it again in a different place with a different unit. And while it wasn't that difficult to do, the penalty if/when caught could be severe. Depending on where the person was, when they did it, and who the C.O. of a unit was (and how strict they were), the penalty for bounty jumping could be anything from fines, imprisonment, to summary execution for desertion.
So, while I can't answer OP's question directly about why their ancestor used an alias during the American Civil War, it MAY have been because they were collecting enlistment bounties. It may have been something like the ancestor was bounty jumping, but they eventually just settled on a unit that had tighter controls on their soldiers, and monitored movements more closely, or just because they felt like they had a good thing going in that unit and didn't want to risk another jump. It's hard to say with any certainty, but in terms of plausible, possible explanations, this is about the best I could come up with. Using an alias would allow a person to keep enlisting in different units without drawing suspicion on a name that might have started to get flagged if a bounty jumper used it enough times. | [
"Although it is unknown what led Lanning to use an alias, aliases were common in the Civil War, often used to prevent people's families from finding them. Lanning was additionally estranged from a number of people in his family; in his widow's pension file, Lanning remarks to his aunt about his deceased parents in ... |
how do they get bottles to break over people's heads so easily in movies? | It's usually sugar glass. Here's [the wiki for it](_URL_1_)
IndyMogul also [has a good how-to video](_URL_0_) if you want to make your own. | [
"The vast majority of bottle cages consist of a single hoop of metal tubing or rod bent to hold the bottle snugly and engage the top, or an indentation in the case of larger bottles, to prevent it from bouncing out.\n",
"To shotgun a beverage, a small hole is punched in the side of the can, close to the bottom. I... |
why are we more attracted to a person when they're tan? | Are we? This seems much more like a personal preference than a universal truth. I searched for your question and found an answer [here](_URL_0_). | [
"Improving appearance is the most-cited reason. Studies show that tanned skin has semiotic power, signifying health, beauty, youth and the ability to seduce. Women, in particular, say not only that they prefer their appearance with tanned skin, but that they receive the same message from friends and family, especia... |
The Emperor of China was believed to be the ruler of all under heaven. If so, what were their opinions of foreign rulers? | Your understanding is exactly right. Even until the late 1800s the majority of the Chinese literati felt outraged as the notion that their Emperor is addressed as an equal by foreign entities. I will give you a few examples:
1) The rivalry of China and Japan could be traced to the point where Japanese rulers were proclaimed "Heavenly Ruler", an epithet which dwarfed the Chinese "Son of Heaven". From this alone you can see how seriously this title was treated with in the East Asian traditional culture.
2) A tutor of Empress Tongzhi of Qing, Woren, wrote, upon hearing that foreigners were to be made language teachers in the Tongwen College, actively believed that it was improper that ANY foreigner should be made a teacher, the most respected career in Chinese tradition.
3) Even until the late 1800s, Western nations were still seen as barbaric by the majority of Chinese literati. Westerners were called "dirty animals" because it was believed they had reeking body odours. Most of the Chinese simply did not believe they were "civilized", and would rather believe the military technology they demonstrated to be brutal and monstrous (linked with the nomadic empires that frequently defeated China's armies in the past) rather than a thing of intellectual and technological advancement.
4) As it could be seen from above, foreign nations were despised and the Chinese, from the Emperor to the people, believed they must be inferior. HOWEVER, the traditional, Confucian monarchical image that Chinese Emperors strived to become was "kind and generous" toward its weaker vassal states. So, if the foreign nation in question was weak and subservient, the attitude of "they are monstrous barbarians" became "they are helpless and our magnanimous selves should offer them assistance". This attitude was literally overnight for the Da Wan, for example. The hardlined, no mercy approach the Hans went with Da Wan occurred ONLY because they would not offer the Han Emperor a really fine horse. Tens of thousands of Han troops died as a result, and once the Da Wan nobility surrendered the kingdom, the Han attitude instantly changed to clemency and they left with a herd of horses, without even so far as entering the city of Da Wan and imposed nothing more to end the war. Another example would be Yang Guang. Yang Guang, Emperor of Sui, believed so much that he must shower his vassals with kindness to show how perfect of a monarch he was, that whenever he held his annual celebration with foreign diplomats, he would offer thousands and thousands of pounds of gold to his vassals. Upon accepting the allegiance of some Turkic hordes, he even went with Turkic tradition to eat in their Khans' tent, allowing them to crown him as the "Sky Khan". Similarly, clemency was pursued whenever China was at war with a foreign power that presented itself as weak.
5）Kublai Khan may not be "Chinese", but his pursuit to be the best of the "Son of Heaven" and his stubborn belief that the entire East Asian region must submit to China lead to some really stupid decisions, such as declaring war on Southeastern nations as far away as Malaysia just because they would not give their tribute on time.
Sources:
Kim, Key-Hiuk The Last Phase of the East Asian World Order: Korea, Japan, and the Chinese Empire, 1860-1882
Chang, Jung Empress Dowager Cixi: The Concubine Who Launched Modern China
Sui Shi
Yuan Shi | [
"The center of this world view was not exclusionary in nature, and outer groups, such as ethnic minorities and foreign people, who accepted the mandate of the Chinese Emperor were themselves received and included into the Chinese \"tianxia\". In classical Chinese political thought, the \"Son of Heaven\" (Emperor of... |
when a large animal at a zoo dies, what is done with its body? | according to a roommate who worked at a zoo, they are often fed to other animals. | [
"The zoo witnessed a series of animal deaths in 2004 and 2005. In August 2004, a Lion-tailed macaque was found mysteriously dead. An emu and a tiger were also reported to have died mysteriously. On 4 September 2004, an elephant died, reportedly of acute hemorrhagic enteritis and respiratory distress. It was reporte... |
What are the rarest cells in the human body that have an important function? | Long-Term Hematopoetic stem cells - These are hematopoetic stem cells that single-handedly have the power to recreate your entire bone marrow and hematopoetic system; we do not know exactly how many of them are there in each human individual, but in mice, for example they just constitute 0.00019% of the cells in just the bone marrow. Yet, they are extremely important (neccessary AND sufficient) for the long term maintenance of the whole hematopoetic system of the mouse (meaning the bone marrow and almost everything that there is in the blood and your immune system). Analogously we might not have more than ten times of that number in humans by best estimates. The most salient aspect of these cells is that in general they almost never divide: in mice these cells seem to divide on average only 5 times in the entire lifetime of the organism.
Even therapy-wise, the study and manipulation of these cells might be the key to a huge number of treatments, including the easy cure of many cancers, HIV & other viral diseases, autoimmune diseases, organ transplant problems, and a lot more! Seriously, if we had one wish and it was that we could master the manipulation of one cell type, it would be this one!
References:
[Wilson, Anne, et al. "Hematopoietic stem cells reversibly switch from dormancy to self-renewal during homeostasis and repair." Cell 135.6 (2008): 1118-1129.](_URL_0_)
[Fuchs, Elaine. "The tortoise and the hair: slow-cycling cells in the stem cell race." Cell 137.5 (2009): 811-819.](_URL_2_)
[Nice summary](_URL_1_) | [
"Due to the different array of markers expressed in these cells, it is difficult to specify their exact cell-type and function. Newer findings propose that pituitary FS cells are made up of groups of cells with disparate immunophenotypes and are not a homogeneous population; however, it still isn't clear if these g... |
why do phone calls consume the most battery on a cell phone? | The answer to both questions is related.
Transmitting a reasonable facsimile of your voice through radio waves is data-intensive. Compare, for example, the size of a digitally-compressed music file (~5 megabytes) to the size of the transcript of its lyrics (1 kilobyte, less than 1/5000 the size). You could send 5000 text messages for every minute of conversation and use a similar amount of bandwidth.
Cell phone carriers are constantly adding bandwidth to their networks, by improving technologies and installing more towers. However, there's no real incentive for them to allocate more of that bandwidth to voice calls by having them transmit at higher quality. The driver of cell network expansion is internet usage. Essentially, the voice works
And because you're transmitting so much data at once as a voice call, and receiving as well, you need to have your antenna operating at full power and your phone has to constantly compress and decompress the phone call data in real time. This takes a lot of computation and a lot of power. When using the internet, you receive small bursts at a time, then use that data. Only when you go to a new web page do you need to download again. And web pages are significantly smaller.
If you want to save battery, send texts and emails. | [
"The 999 phone charging myth is an urban myth which claims that if a mobile phone has low battery then dialing 999 (or any regional emergency number) charges the phone so it has more power. This was confirmed as a myth by several British police forces who publicly cited the dangers of making such calls.\n",
"The ... |
What are the effects of the smoke generated by the fires in Australia? | Hi! Atmospheric chemistry PhD here. I researched wildfire smoke composition and health effects in graduate school. I'm currently doing postdoctoral research in medicine trying to understand the finer details of air pollution toxicity.
Here's a few quick things about wildfire smoke!
**What's in the smoke?**
A complex mixture of fine particulate matter and gasses. The composition is very complicated as there are hundreds to thousands of different compounds that transform as the smoke plume moves from the source. You will find NOx, CO, CO2, lots of organic carbon, black carbon/soot, inorganic salts and a smaller but still significant amount of transition metals (iron, copper, zinc, aluminum among others).
**How does the smoke impact climate?**
The brown and black wildfire particle absorbs incoming solar radiation and increases warming while the smoke is present. However, the magnitude of warming by wildfire smoke is uncertain and researchers are actively researching this and other impacts on the climate system. Furthermore, the wildfire smoke particles may provide a favorable surface for water molecules to condense on, thereby driving cloud formation. See pyrocumulus clouds.
**How does the smoke impact health?**
Wildfire smoke produces toxic gases and fine particulate matter. In general, long and short term exposure of fine particulate matter has been associated with chronic inflammation, increased heart diseases, lung diseases, cancer, and death rates. Recent estimates suggest that \~80% of air pollution deaths are due to cardiovascular effects. Human and animal studies have consistently shown that particulate matter inhalation produces a pro-inflammatory response. **Recent epidemiological work has suggested that wildfire smoke is MORE TOXIC than urban air pollution particles.** We still don't know the specific chemicals and biological mechanisms associated with the toxic effects of smoke inhalation.
**EDIT, PSA ABOUT RESPIRATORS:** If you are concerned about smoke exposure and are not in immediate threat of fire: Get a respirator that filters fine particulate matter and organic vapors if possible. 3M has some pretty good ones. The white dust masks that strap around your face don't block fine particles and organic gasses from entering your lungs!
Best wishes and hope for the safety of our friends in Australia.
\*\*Minor edits for grammar
\*\*Edited to say long and short term exposure to particulate matter is associated with detrimental health effects, rather than just long term. | [
"Haze is caused by \"hotspots\" (zones with high temperature levels as seen via satellite imagery) in Malaysia and Indonesia. Lingering smoke from forest fires on the Indonesian island of Sumatra are identified as the primary cause. Farmers regularly burn scrub and forest to clear land during the dry season for agr... |
scary movie decisions | Understanding this is as simple/complicated as understanding the nature of art and catharsis itself.
If the end goal is to stimulate a psychosomatic response in the viewer, certain tropes prove effective towards that end goal. They're not painting rational life portraits--they're just storytellers, executing their craft with tools from an ancient toolkit. | [
"On working with feature movies: \"You need to be honest, because this way your audience will be able to identify with the topic and the hero. My role, as an artist, is to prepare a text with open questions and hide the fact that I have an answer key. Questions will provoke audience to discuss the film and seek new... |
What happens when a bee or wasp hitches a ride in your car, then gets out of the car a long distance from home? | According to a study by the Australian National University, bees are very good at finding their way home, even over long dustances, and often rely on the position of the sun, the polarisation of light in the sky, the panorama view of the horizon and landmarks including towers, mountains or lakes.
From that article: “In their forage trips, one way that honeybees use to find their way home is by storing distance and directional information when they venture out,” said Professor Zhang. “In other words, they try to go back the way they came."
So bees rely on landmarks, the sky, and a general bearing of what direction they have traveled and can make it back home, even if it takes them multiple days. Though this probably begins to fail the further they go from the hive.
Source: _URL_0_ | [
"If you slowly approach a perched individual during hot weather then it may repeatedly fly up and grab any mosquitoes or freeloader flies circling around you, often returning to its original perch to feed for several minutes after each catch.\n",
"In 2010 the Australian Civil Aviation Safety Authority (CASA) issu... |
Why is it not yet economically viable to genetically engineer an organism to produce motor fuel from waste materials? | There are certainly gas-producing organisms that generate methane from garbage, and in fact there are efforts to commercialize this kind of technology (look up 'biogas').
The problem is these processes are not very efficient. The molecules you are talking about have an extremely high energy density, and it's difficult to coax a living organism into sacrificing its scarce energy budget to making high-energy molecules that it does not consume for its own benefit.
Meanwhile, this stuff is still coming out of the ground for relatively cheap. | [
"With the potential future creation of man-made unicellular organisms, some are beginning to consider the effect that these organisms will have on biomass already present. Scientists estimate that within the next few decades, organism design will be sophisticated enough to accomplish tasks such as creating biofuels... |
Why can't phone chargers/ charging ports have a higher voltage, thus charging faster? | They do. Various "QuickCharge" technologies use higher voltage output (compared to the default 5V) on the charger to allow for faster charging.
Since almost all phones (and other mobile devices) use a USB port (micro-USB or USB-C) for charging, most manufacturers tended to stick to the USB specifications to prevent compatibility issues. These specs have long limited the output voltage to 5V. This means that fast charging solutions tend to not be in compliance with USB specifications.
In recent year, the USB standards have been expanded with the possibility to use higher voltages for power delivery. This allows devices, such as certain MacBook models, to be charged at higher speeds using spec-compliant USB connections.
But other than adherence to standards, there's a more practical limitation on fast charging, which is heat generation. Charging requires certain hardware to transform the incoming power to the right voltage for the battery being charged and these charging electronics produce heat. The more power you run through them, the more heat they produce and this heat is detrimental for the operation of the device (especially since mobile devices are so compact and have very limited means to shed heat).
One way to combat this issue, as employed by OPPO and OnePlus, is to move as much of the power conversion electronics into the charger, which reduces heat generation in the smartphone (but makes the charger run much hotter). But even then there are limitations to how quickly you can charge a battery without it having detrimental effects. | [
"Since these currents are larger than in the original standard, the extra voltage drop in the cable reduces noise margins, causing problems with High Speed signaling. Battery Charging Specification 1.1 specifies that charging devices must dynamically limit bus power current draw during High Speed signaling; 1.2 spe... |
What are some historians' opinions on Jan Gross' book Golden Harvest which is about Polish collaboration with Nazi atrocities against Jews? | I'm not a historian, nor have I read the book, but.. Fear makes otherwise decent people do terrible, terrible things, like collaborating with Nazis. You could point fingers at basically any country that was controlled by the Reich for a period of time and find collaborators, even among the Jews themselves. That's not excusing their actions, of course, but a book like this could be written about any group of people during that time period.
Just my two cents.
Edit: And it seems my view of concentrating blame on one group is shared by at least one reviewer.
_URL_0_ | [
"Historian Grzegorz Rossoliński-Liebe, writing in \"H-Soz-Kult\", reviewed three books: \"Judenjagd\" by Grabowski, \"It Was Such a Beautiful Sunny Day\" by Barbara Engelking, and \"Golden Harvest\" by Jan T. Gross. He wrote that all three studies are noteworthy explorations of the Polish participation in the Holoc... |
how come a sound gets longer the more of it there is? | Sounds dont get longer the more there is, if you look at the video you can see that the videos arent all playing at the same time, there's a delay in some which can be seen by the wave like motion of the videos in the later parts of the video. | [
"Duration is perceived as how \"long\" or \"short\" a sound is and relates to onset and offset signals created by nerve responses to sounds. The duration of a sound usually lasts from the time the sound is first noticed until the sound is identified as having changed or ceased. Sometimes this is not directly relate... |
what would happen if the federal reserve/congress placed a forever permanent "cap" on the amount of dollar bills in circulation? | Just based on a supply and demand logic, I imagine that money would get more valuable...a dollar bill would be equal to a greater amount of commodities. As more "things" were produced but the amount of money remained the same, it would seem to me that one unit of money ($1) would be worth an increasing share of product "X". I realize my scenario is very simplistic and assumes that more "things" would be produced as well as leaving out other factors. Maybe an economist could help. | [
"The United States Government Accountability Office (GAO) has stated that discontinuing the dollar bill in favor of the dollar coin would save the U.S. government approximately $5.5 billion over thirty years primarily through seigniorage. The Federal Reserve has refused to order the coin from the mint for distribut... |
how do record players and records work? they constantly spin, but if you lift the needle off and put it back down it knows where it left off, right? or am i way off there and it does actually skip ahead if that happens | It goes down near where it went up but not precisely, the rotation is variable, but the arm is normally still in the position across the record (from the edge to the centre). Basically the needle follows the grove on the record which is a tight spiral moving in towards the centre, with the bumps in the grooves being where the music is recorded. | [
"The mechanism causes the lower portion of the spindle to rotate clockwise like an ordinary record player, while the top half of the spindle rotates counterclockwise to permit the bottom of the record to be played in the correct direction. The spindle contains three sets of retractable claws which hold the records ... |
What's worse for your body: a bottle of soda, or a bottle of beer | A little bit of alcohol might actually be good for you. | [
"However, the most striking feature of \"Beer Bad\" is the twin moral: Beer and casual sex are bad. In a BBC interview, Petrie states: \"Well, very young people get unlimited access to alcohol and become horrible! We all do it — or most of us do it — and live to regret it, and we wanted to explore that.\"\n",
"Be... |
why do people put gold on food, other than the purpose of showing off how rich they are? | Flaunting wealth is often one reason. However, if you consider food to be an art form, putting gold on the plate could be completely a creative expression of the chef. We eat first with our eyes, gorgeous plating goes a long way towards creating a multisensual dining experience. | [
"Gold has worked to evaluate the hypothesis that hedonistic overeating is a pathological attachment to food like any other addiction. Gold is a co-editor of the 2012 textbook, \"Food and Addiction\", published by Oxford Press. More recently, Gold also co-authored: Why are we consuming so much sugar despite knowing ... |
What happened to people in jail during the Great Depression? If the public could barely afford to live how could prisoners? Did any of them die from starvation or were they all adequately fed? | I have an add-on question. How true was it that the average person 'could barely afford to live'? I've heard anecdotal stories from older relatives of small southern towns being basically unaffected by the depression. | [
"Overcrowding soon became a big concern, as well as poor sanitation. The jails turned into breeding houses of illness. Furthermore, the jails were even unable to fulfill their basic purpose of containing offenders within its walls. Escapes were very frequent. The prisons held not only those who were awaiting trial ... |
Does Earth experience a tidal force from Sun? | Yes, we experience a tidal force from everything, it's just question of magnitude.
[The tidal force from the Sun is about ~~3%~~ 44% as strong as from the Moon](_URL_0_), because unlike the basic gravitational force, the tidal force drops like 1/r^3
Edit: 44% | [
"The tidal force on Earth due to a perturbing body (Sun, Moon or planet) is expressed by Newton's law of universal gravitation, whereby the gravitational force of the perturbing body on the side of Earth nearest is said to be greater than the gravitational force on the far side by an amount proportional to the diff... |
single variable calculus, specifically the differentiation of elementary functions. | Do you mean taking derivatives using the definition, or using the tricks and rules you can memorize to make it easier/faster? | [
"Elementary calculus is the calculus of real-valued functions of one real variable, and the principal ideas of differentiation and integration of such functions can be extended to functions of more than one real variable; this extension is multivariable calculus.\n",
"Elementary Functions- a study of the elementa... |
why after a good long cry can't we take a big deep breath without that huh-huh-huh tracheal contraction? | Intense crying can cause less oxygen to enter the brain, therefore the contractions are like yawning, it’s supposed to allow more oxygen to enter.
Source: I’ve cried once. And took an anatomy class once. | [
"This happens due to elastic properties of the lungs, as well as the internal intercostal muscles which lower the rib cage and decrease thoracic volume. As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put pressure on the lungs to expel the air. During... |
why is it ok for generic brands to blatantly rip off brand name companies for their own profit? | Its not, I cant call my cereal frosted flakes. I cant use the image of tony the tiger. But There is nothing to stop me from making "Frosted cereal shards" putting them in a blue box and having my mascot be a lion, why would there be? | [
"Some generic products may try to leverage their existing cost advantage (due to lack of promotion) further by using inferior ingredients for production. This can damage the reputation and lead to customers avoiding future purchase. Prevalence of such acts necessitates the customer crosschecking the crimp for list ... |
Who are some of the better known Chinese artists? | The answer is that we know quite a lot about many of the great Chinese masters. However, the history of art in China goes back a deal further than europe. So provenance becomes a major issue. This is particularly the case with the monumental landscape masters of the 10th and 11th centuries. I will mention a few of them below, but first I will mention an exemplary problem - that of Zhang Daqian - a brilliant 20th century painter, scholar and trickster. He was the top chinese scholar in the field, so when he brought out a newly discovered 10th century masterpiece, all had to take note. But he clearly was the *10th century master* behind several of them. He would paint them, then take them to the basement, get them all dusty, stomp on them, burn some edges, forge some imperial seals, etc, then he would unveil them with much fanfare. You seriously have to love this guy! Anyway, on to the original masters:
Li Cheng - the true father of monumental landscape, but also the most difficult to attribute. His ink on silk work is well documented in writings, but the authenticity of each of the surviving pictures themselves is doubted by at least some art historians. I remember looking at two different Li Cheng attributions at the Metropolitan museum (grad seminar on Song dynasty art). One was entirely vexing. It just seemed disjunct, as if of two minds. Though some had argued vigorously for its authenticity, it just never settled with me. But the other was spectacular. It was mesmerizing, truly, as much or more so than the Leonardos and Raphaels I had seen in florence and rome in years past. I remember thinking that I didn't care whether it was a Li Cheng, because, in the words of my professor, it was what a Li Cheng "Ought to look like". He also said that we should all become comfortable with ambiguity if we were to look at chinese pictures.
The second master worth looking at is Fan Kuan. [this](_URL_1_) is his most famous work. I cannot add much about him. Great painter.
The greatest of all though was Guo Xi. His [Early Spring](_URL_0_) is that rarest of early chinese paintings - signed, dated, almost universally accepted as authentic, and hanging in the Taipei palace museum. This painting is truly the landscape to measure all others both that came before and after.
I have seen a handful of song dynasty paintings up close, due to sheer luck in choosing the right course! I count those moments among my very luckiest and most special experiences with visual art. Although these artists are extremely well known in China, Korea, and Japan, they are sadly almost totally unknown in the art loving west.
Beyond the Song there are many wonderful artists, and luckily we know much more about them. Do some searching for great painters of the Ming and Qing, and you will find more than enough to keep you in a wiki vortex for several days. Enjoy! | [
"Zhang Daqian or Chang Dai-chien (; 10 May 1899 – 2 April 1983) was one of the best-known and most prodigious Chinese artists of the twentieth century. Originally known as a \"guohua\" (traditionalist) painter, by the 1960s he was also renowned as a modern impressionist and expressionist painter. In addition, he is... |
magnet torrent links. what are they? | A magnet torrent link is a unique set of numbers and letters that describe a specific file, like a fingerprint. Torrent clients can use this fingerprint to ask other clients if they have a file with the same fingerprint. If they do, they can send it from them (peer) to you (peer). | [
"the original research are implemented. Other file sharing networks, such as the Kad network, use distributed hash tables to index files and for keyword searches. BitTorrent creates individual overlay networks for sharing individual files (or archives). Searches are \"performed\" by other mechanisms, such as locati... |
How did it come to be that all of the genes relating to sex are on the same chromosome? | They aren't: the genes that **trigger** (specifically, SRY) the male phenotype are on the Y chromosome, but males also have a complete set of female DNA, and ~~many~~ almost all of the distinctly male characteristics are side effects of this trigger alone. And even this is a little bit of a misnomer, as SRY (or lack of SRY) and the Y chromosome do not clearly cut human gender:
[_URL_0_]
[_URL_2_]
[_URL_5_]
[_URL_4_]
SRY makes it easier to be a different gender, which arose from a selection for ansiogamy (different types of gametes). This is because having a low energy cost, low success gamete (in humans, male sperm) and a high energy, high success rate gamete (in humans, the female egg) had an overall higher chance of being fertilized and "mitigate fertilization risks". There are also theories that competition between the low-cost male gametes contributes to the selection for anisogamy.
[_URL_1_]
[_URL_3_]
| [
"Many species have so-called sex chromosomes that determine the gender of each organism. In humans and many other animals, the Y chromosome contains the gene that triggers the development of the specifically male characteristics. In evolution, this chromosome has lost most of its content and also most of its genes,... |
Do bra-less women have lower rates of breast cancer? | _URL_0_
*Factors not likely related to risk*
*Although not as well-studied as the factors described above, based on the research to date, the factors below are not likely related to breast cancer risk.*
*Bras/underwire bras*
*Scientific evidence does not support a link between wearing an underwire bra (or any type of bra) and an increased risk of breast cancer. There is no biological reason the two would be linked, and any observed relationship is likely due to other factors. A 1991 case-control study found that premenopausal women who did not wear bras had a lower risk of breast cancer than women who did wear bras [487]. However, the authors stated this link was likely due to factors related to wearing a bra rather than the bra itself. The women in the study who did not wear a bra were more likely to be lean and have small breasts, which the authors concluded might account for the link [487].* | [
"HRT has been more strongly associated with risk of breast cancer in women with a lower range body mass indices (BMIs). No breast cancer association has been found with BMIs of over 25. It has been suggested by some that the absence of significant effect in some of these studies could be due to selective prescripti... |
why some metals glow brightly when hot (i.e., steel or iron) when others just look like liquid metal (i.e., aluminum or mercury)? | Aluminum and mercury will glow too if you get them hot enough. Pretty much everything glows (incandesces) at the same temperature, aluminum and mercury just happen to melt before that temperature whereas steel melts at a higher temperature. | [
"Iron or steel, when heated to above 900 °F (460 °C), glows with a red color. The color of any heated object changes predictably (due to black-body radiation) from dull red through orange and yellow to white, and can be a useful indicator of its temperature. Good quality iron or steel at and above this temperature ... |
how do wammy bars (on guitars) work? | Basically you use the bar to add extra tension to the strings to shift the pitch as you play. | [
"The \"barbat\" is held similar to a guitar, but care must be taken to have the face vertical so that it is not visible to the player, and to support the weight with the thigh and right arm so that the left hand is free to move around the fingerboard. Note the idiosyncratic manner of holding the \"mizrab\" (Turkish... |
why do some people have no sense of rhythm whatsoever? | As an audio engineer, I've broken this down a few times. There are two types of people: 1. People who dance to the beat (kick drum and snare) 2. People who dance to the vocal melody/lyrics.
| [
"An individual with this condition has an especially difficult time maintaining a steady beat, and even has difficulty following along to a steady rhythm. Before it was a known disorder, it was thought that these individuals were just severely uncoordinated, and therefore were unable to follow along with the music.... |
Does the Cambrian Explosion coincide with the move from ocean-based to land-based life forms? | In general it is presumed that the Cambrian Explosion happened essentially in the ocean and maybe to some degree in lakes and rivers. According to wikipedia (_URL_0_) land plants began spreading 490 mya ago and I am quite sure that multicellular animals on land needed those for nutrition.
Anyways, your theory would not work: The mutation rate is in general a parameter that evolves towards an optimum. If the environment leads to increased mutation rate, all species will evolve some protection mechanisms to the point where the risk of harmful and advantageous mutations is again balanced. | [
"The \"Cambrian explosion\" can be viewed as two waves of metazoan expansion into empty niches: first, a coevolutionary rise in diversity as animals explored niches on the Ediacaran sea floor, followed by a second expansion in the early Cambrian as they became established in the water column. The rate of diversific... |
how can rocket boosters push things foreward and navigate in space when there is no atmosphere to use? | You would need an atmosphere for things like paddles and propellers. Because they have to push air to work.
Rocket thrust is different. Equal and opposite reaction, right? The rocket fuel or exhaust goes out the back *and pushes the rocket forward*. The force only has to act on the rocket, not against another medium. | [
"Rocket propellant may be expelled through an expansion nozzle as a cold gas, that is, without energetic mixing and combustion, to provide small changes in velocity to spacecraft by the use of cold gas thrusters.\n",
"The rocket booster would place the vehicle onto a suborbital, but exoatmospheric, trajectory, re... |
Does evolution ever stop? | Correct, since Evolution is a slow process in which the traits of a given generation are passed on (due to their survival), as the Environment changes, so too would the requisites of survival change.
Consider an organism that exists in an ecosystem that is devoid of outside influences:
As the organism evolves through the generations, its mortality rate drops and there are more organisms in the environment. Eventually the population would reach critical mass, and the organisms would start dying off, except for those who are uniquely adapted to a high population colony, limited food supply or some other feature.
The previously 'optimal' traits are no longer relevant, as the organisms themselves changed the environment, ergo the system of trait selection continues under the new paradigm.
TLDR; Evolution will always continue as systems are prone to break down and change. | [
"Bateson suggested that all evolution is driven by the double bind, whenever circumstances change: If any environment becomes toxic to any species, that species will die out unless it transforms into another species, in which case, the species becomes extinct anyway.\n",
"According to Thomas S. Ray and others, th... |
What was the average day like for an allied soldier in post WWII Germany before the rise of the Soviet threat? | I've not done research in the matter, but my grandfather volunteered to stay on occupation duty with the Canadian Army.
From what he said the days were fairly boring. He was around Baden, so not a Nazi stronghold like Bavaria. The people were broken, trying to rebuild some semblance of life after the war. He was a universal carrier driver, so he ran a lot of errands for his CO, jockeyed engineers around the countryside, went on patrols. The biggest problem they ran into was crime. Society was basically ripped apart, so they spent a lot of time making sure there was no looting. They ran checkpoints looking for war criminals (SS I assume), and basically just went about their days overseeing people trying to get back to normal. He said it wasn't terribly exciting, though one day his CO and some other bigwigs made an announcement that there was going to be a trial and they wanted there to be guards there from every allied country. He declined, because, who cares, right? Turned out it was the Nuremberg Trials. He kicked himself for that one, even though if he went he probably would just have been manning roadblocks on the Pegnitz instead of in Baden, but still, it would have been neat to be a part of.
From what I understand, the German people were quite happy to put the war behind them and try to move on with their lives, and the biggest threats were crime, food shortages, and drunkeness driving/outbursts. | [
"During World War II, between 1941 and 1944, the german Wehrmacht ran a prisoner-of-war camp (Stalag 333) there for Soviet soldiers. More than 30,000 of them died from harsh treatment and malnutrition.\n",
"During 1945 it was estimated that the average German civilian in the U.S. and the United Kingdom occupation... |
why are some men able to grow a beard and others not? is growing a beard a sign of of wellness? | some of it is diet but more of it is gentics. Asians for example tend to have a lot harder time and are less likely to grow a full on beard as you see it other races
fun fact it was seen as very special if you could in many asian cultures | [
"Many men in Western cultures shave their facial hair, so only a minority of men have a beard, even though fast-growing facial hair must be shaved daily to achieve a clean-shaven or hairless look. Some men shave because they cannot grow a \"full\" beard (generally defined as an even density from cheeks to neck) bec... |
What sort of tactics did the Muslim armies use during the Crusades? How different were they to the Crusaders? | While moving through Asia Minor the First Crusade was confronted with armies composed almost entirely of cavalry. These Turkic armies consisted largely of light cavalry who fought with bow and arrow from horseback much like their nomadic brethren/ancestors. They used mobility to exhaust and demoralize their opponents in order to break their formation or to separate them. When they had succeeded they would finish the job in a final attack together with the heavy cavalry. While the complete absence of infantry was a typical Turkic thing and not representative for the islamic armies of that era, infantry often played a subordinate role in the eastern armies.
- France, John, ‘Crusading warfare and its adaptation to Eastern conditions in the twelfth century’, *Medieval Warfare 1000-1300*, ed. John France (Aldershot 2006) p. 55
The Franks, confronted with an enemy who kept attacking them but didn't let itself be attacked, were forced to adapt their tactics. The best weapon they had against horse-archers were their own bows and, more importantly, their crossbows. However these archers and the Franks main weapon, the heavy cavalry, needed to be protected against enemy fire even when moving(from fortification to fortification). Furthermore it was essential that the enemy wouldn't be able to separate parts of the army.
The Franks' answer according to Smail was the 'fighting march'. The goal was to have the infantry shield the cavalry from enemy fire while keeping the enemy at a distance with their own (cross)bows.
This was hard enough when standing still, but the crusaders needed to be able to do this while moving between castles/strongpoints. Therefore they marched in the fighting march formation instead of the normal column formation. Arabic commentary from the period describes the formation as "a moving castle, where the walls and towers are made of infantry". The cavalry and supply-train would be moving inside that castle.
Discipline is very important when using this tactic. Not only did the Franks have to hold their formation under heavy fire(comparable to machine-gun fire when concentrated against a small section of the line) while moving. They also needed to open the formation at the right moment in order to allow the heavy cavalry to perform their *charge-en-masse* when the time was right for the counterattack.
- Smail, R.C., *Crusading warfare 1097-1193* (Cambridge 1995) p. 156
Scholars have given many reasons for the crusaders' use of the *charge-en-masse* as it was rarely used in Europe and often involved just a small detachment. France cites the Franks' need for a psychological superiority or dominance as the main reason. They needed to seem powerfull and fearless to maintain their political and military might. They needed to impress. Personally I think the image the muslims had of the 'famous charge' was a consequence rather than a cause.
The reason Bennet suggested seems more plausible. A well-timed cavalry charge was the only offensive weapon they had. They couln't hold indefinitely while using their infantry purely for defense. They had to force a decisive battle, timing was crucial.
- Smail, R.C., *Crusading warfare 1097-1193* (Cambridge 1995) p. 203
- Bennet, Matthew, ‘The crusaders’ fighting march revisited’, *War in history 8* (2001)
Discipline was kept by assigning soldiers specific places in the formation which they weren't allowed to leave(this wasn't common during this period) unless ordered to. Obviously those who disobeyed were severely punished.
A second reason was the example set by the members of the military orders. These orders who relied on discipline for their entire way of life were exceptionally good at holding formation when faced with taunts and feigned retreats. For this reason Richard the Lionheart and Louis VII used the military orders as the van- and rearguard of their armies. Templars in the van and Hospitallers in the rear.
- Smail, R.C., *Crusading warfare 1097-1193* (Cambridge 1995) p. 198
Lastly, the crusaders also employed light cavalry of their own. They used locally recruited Turkopoles in essentially the same role as the muslim armies did, though they never had as many of them.
- France, John, ‘Crusading warfare and its adaptation to Eastern conditions in the twelfth century’, *Medieval Warfare 1000-1300*, ed. John France (Aldershot 2006) p. 58-59
For most of the period warfare in the Levant can be characterised by the modern term of low-intensity-conflict. Achieving the primary war-aims(capturing fortifications=land=wealth) was often difficult or impossible so both parties resorted to harassing the enemy and raiding for loot. While for the muslims the *chevauchée* or raid was just part of their strategy in order to weaken the Franks for the eventual siege of a certain castle, for the crusaders raiding became the only way to keep the enemy at bay as the number of crusaders started to dwindle. The Franks were defending an area the size of England and Wales with just 12.000 troops, they were fighting a losing battle.
| [
"The Muslims lay in a semicircle east of the city facing inwards towards Acre. The Crusader army lay in between, with lightly armed crossbowmen in the first line and the heavy cavalry in second. At the later Battle of Arsuf the Christians fought coherently; here the battle began with a disjointed combat between the... |
[Physics] Where does the mass come from in fusion or fission? | The mass difference comes from the binding energy of the nuclei, via E=mc^(2). | [
"Due to spontaneous fission a supercritical mass will undergo a chain reaction. For example, a spherical critical mass of pure uranium-235 will have a mass of 52 kg and will experience around 15 spontaneous fission events per second. The probability that one such event will cause a chain reaction depends on how muc... |
why does boiling contaminated water make it drinkable? | The heat kills bacteria and other potentially icky things in the water. It's not fool proof but it's better than nothing. | [
"Water must be purified of harmful living organisms and chemicals. Some commercial filters can remove most organisms and some harmful chemicals, but they are not 100% effective. Distillation filters, purifies, and removes some harmful chemicals. Chemicals with a lower or about equal boiling point of water are not e... |
how do they fix power lines when a tree falls on them? | They shut off power to the line and then rebuild it. Power lines are kind of like tinker toys. You just replace the parts that need replaced. Everything from the wire to transformers. If a pole is broken, they cut it off and plant another one. | [
"Areas with large trees and branches falling on lines are a problem for aerial bundled cables as the line degrades over time. Due to the very large strain forces cracking and breaking insulation can lead to short circuit failures which can then lead to ground fires due to dripping of molten insulation.\n",
"Trees... |
Where does rust go? | This depends on the metal! When iron combines with oxygen in the atmosphere, the resulting iron oxide compounds take up much more space than just the metal did, but more importantly they don't have much structural strength. This means that the growing layer of rust on the outside cracks and flakes, creating gaps that let air react with fresh iron underneath. What happens over time is that the oxygen combines with all the metal from the outside in, atom by atom, until it has all turned into flaky crumbly rust and fallen off.
The other end of the spectrum is something like aluminum, which *does* react with oxygen just like iron does. Aluminum oxide, however, is so much tougher than iron oxides. Aluminum oxide is actually the major part of minerals like sapphire, which is more scratch resistant than glass and is what high-end phone screens and watch faces use. When the outermost layer of aluminum metal reacts with air, it forms a super thin but pretty solid and tough layer of aluminum oxide that actually protects the fresh metal below. After this first layer, the metal stops oxidizing. This is called a passivation layer.
Then of course there are some metals like gold that don't react with oxygen under atmospheric conditions to begin with. | [
"Rust is a mixture of iron(III) oxide and oxide-hydroxide that usually forms when iron metal is exposed to humid air. Unlike the passivating oxide layers that are formed by other metals, like chromium and aluminum, rust flakes off, because it is bulkier than the metal that formed it. Therefore, unprotected iron obj... |
Can gravitational lenses (or a series of them) turn a light source back on itself? | This can happen near black holes, where the path of light can be bent so much that it passes the event horizon. However, to modify the path of a distant star back to its direction of origin would require the perfect setup of perfectly placed black holes which is so unlikely as to never happen. | [
"A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer. This effect is known as gravitational lensing, and the amount of bending is one of the pre... |
how american football divisions and pre games work (not the rules of the sport) | Pregame, are just exhibition games. They are sometimed used to help determine who gets the last few spots on a team's roster. Divisions are groups of 4 teams. There are 4 divisions per conference. Every team in a division plays eachother twice, as well as 8 teams outside of their division. This is how you get big divisional rivalries, since every year you are guaranteed play the same 3 teams. The best team in each of the 8 divisions gets a playoff slot. The wildcard slots are taken by the best teams which didn't win a division. | [
"Brackets are commonly found in major North American professional sports leagues and in U.S. college sports. Often, at the end of the regular season, the league holds a post-season tournament (most commonly called a playoff) to determine which team is the best out of all of the teams in the league. This is done bec... |
Am I seeing the history of the sun? | Yes but using that logic you are seeing the history of everything. because there is a delay between the object you are looking at and the light hitting that object, reflecting off, and hitting your eye. Similarly there is a delay between when your nerves endings in your eye or skin are triggered and your brain processes them.
You not only do you see the past but live in it too
Edit: Spelling | [
"\"The Sun\" first gained notice for its central role in the Great Moon Hoax of 1835, a fabricated story of life and civilization on the Moon which the paper falsely attributed to British astronomer John Herschel and never retracted. On April 13, 1844, \"The Sun\" published as factual a story by Edgar Allan Poe now... |
why does putting clear (scotch/packing) tape on a frosted window let you see through it? | Frosted glass is simply glass with a (chemically) roughened surface which causes the light passing through the pane to diffuse in all directions, instead of letting straight through.
(Scotch) tape is essentially a clear plastic surface coated with a thin layer of transparent adhesive. When you stick it to frosted glass the adhesive fills the small cavities on the glass surface which were made by the chemicals used to frost it. The adhesive thus smoothens the surface, counteracting any diffusion.
This also means that the tape trick only works on chemically frosted glass, or mechanically frosted glass with a fine texture, because the thin layer of adhesive can only smoothen out relatively small cavities in the glass.
Edit: thanks for the silver!
Edit 2: and thanks for the double silver and the gold!! | [
"brwhy this tape sounds the way it does.bralthough it could be argued that the tape sounds this way because I'm dumb, I would prefer you think it's because rooms, recording tape and tape machines are not invisible.br-- Al.\n",
"To prevent the recording on the tape from being erased, there is a small write-protect... |
During the American Revolutionary War, 42,000 English Redcoats deserted. Where did they go? What happened to such deserters stranded in foreign territory? | Can you please link this because I can not find that 42,000 English redcoats deserted from an army that averaged about 39,000 soldiers in the colonies during the war? | [
"During the French and Indian War (the North American theatre of the Seven Years' War), the Acadians were expelled from Grand-Pré during the Bay of Fundy Campaign (1755). There were various British soldiers who kept a journal of the deportation from Grand-Pré such as Lt. Col. John Winslow and Jeremiah Bancroft. The... |
What happened to the indo-greek states? | [/u/Daeres](_URL_1_) posted a great answer to a similar question yesterday on [/r/badhistory](_URL_0_). I've quoted it here for those who haven't read it yet:
> Some necessary background- Alexander III of Macedon's conquests (or Alexander the Great if you prefer) in what is now Pakistan and Central Asia were not without impact. Whether you're familiar or not with the aftermath of Alexander the Great's death in 323 BC, suffice to say that eventually these possessions deep in Asia came into the possession of one Seleucus. Alexander already had planted, it seems, several forts with garrisons and colonists in this part of the world. Seleucus had additionally flooded these areas with more Greek settlers and began the construction of additional cities. This got interrupted close to 300 BC by the emergence of a big Empire in India- the Mauryan Dynasty under one Chandragupta Maurya. The easternmost possessions of Seleucus became threatened by the emergence of Chandragupta, and a conflict seems to have been ensued. Much is unknown about these incidents, but it seems the 'Indian' possessions of Seleucus along with others in modern Afghanistan were ceded to Chandragupta. Seleucus, and his dynasty the Seleucids, retained control of what is now northern Afghanistan- these include regions at the time that were called Bactria and Sogdiana.
> Despite the fact that these areas had been conquered/ceded to the Mauryans not two decades after Alexander had conquered them, the Greek communities that had been established there seem to have been incredibly vibrant. We say this because even 60 years later, these communities seem to have been intact. One of our biggest indicators is that their Mauryan rulers erected administrative inscriptions in Greek, of all things, at the site of Old Kandahar. It indicates that they were considered important enough that they were worth courting, and vibrant enough that it was considered worthwhile. It's also good, grammatical Greek as well, rather than what many inscriptions tend to do which is pretty ungrammatical nonsense.
> This is what we'd call the Indo-Greeks- the Greek communities in what at the time was controlled by the Mauryan Empire, and were thus subject to the control of an Indian-centred polity. They're differentiated from other Greeks because their cultural environment and day to day experiences were fundamentally different from others.
> Now, I mentioned Bactria and Sogdiana earlier. These areas were also heavily settled by Greeks, with an existing population of Iranian speaking Bactrians+Sogdians, some settlers that were likely from the neighbouring Scythian societies, and probably Persians left over from the Achaemenid (Persian) Empire's control of the region. The Seleucid Empire kept hold of them, but somewhere around the 240-230s BC the satrap (essentially governor but directly royally appointed) of Bactria became independent. Fast forward to the 190s-180s BC; the Mauryan Empire seems to have fragmented, and the Greek-ruled kingdom of Bactria seems to have dogpiled- this is the situation which leads to the map that /u/caesar10022 posted, where there's an Indo-Greek kingdom sitting in India launching expeditions and conquests. The circumstances in which the Indo-Greeks became partially separated from the Greco-Bactrians who conquered/liberated/sponged them are still not fully comprehended, and it is surprisingly difficult to work out who rules what at any given point. However, by about 140-135 BC all of this had come to an end; the Greco-Bactrian kingdom had been invaded by somebody, probably Scythians or similar peoples to their north. Across a century or so, the various remaining Indo-Greek kingdoms got swallowed up.
> But, and this is where I start to get into the meat of the subject, this is not the end of Greek culture or influence in Central Asia or North-West India. The Greek alphabet was adapted to write the language of Bactria itself (Bactrian, natch), with two additional signs for new signs. The Kushan Empire, which emerged in Bactria and surrounding areas sometime after the last Indo-Greek state was conquered, continued to recognise Greek deities on their coinage for centuries afterwards alongside Iranian and Indic deities (this coinage, by the way, looking very similar to Greek-style coins). They also became enormous patrons of Buddhism, complete with representations of Buddha on their coinage and building enormous stupa complexes across their Empire. These stupas incorporated many Greek architectural elements, including Greek style pillars and representations of certain Greek figures like Hercules and Atlas. Indeed, the Greek connection with Buddhism appears to be even older than this; one King Menander, who seems to have controlled a kingdom including bits of Bactria and the city of Taxila, is believed to be the subject of a Buddhist philosophical text called the Milinda Panha. If this identification is correct, and we believe it to be, that makes Menander an incredibly important early patron of Buddhism. We can see from his coins that he issued bilingual coins as well, some of which may have incorporated Buddhist imagery.
> It is clear that a self identifying Greek culture vanished from these regions eventually, probably by about 300 AD or thereabouts (we are having to guess a little). But the period of Greek settlement and its aftermath left a huge impact in these areas- I'm not arguing they 'civilized' them, Bactria had been building cities and irrigation canals for almost 2000 years by the time Greeks ever arrived there, and India is home to some of the earliest urban sites we are aware of anywhere in the world. However, it would be impossible to deny that Greek culture became part of the tapestry of influences and ideas that underlay many cultures in the area. Hellenistic era Greek culture is as much part of the heritage of Central Asia and Pakistan as it is in the Mediterranean, I would argue. So to argue that the Indo-Greek kingdom is not important is, frankly, rather annoying and silly. In fact, anyone who argues that any culture/state is unimportant to history should be treated as a little suspect.
> To close this rather lengthy rant, there are a number of fairly pretty pictures of much of what I have spoken that I can dig up if people want me to. However, I would also like to point out that if King Menander was indeed the 'Milinda' of the Milinda Panha, then that makes him someone respected both in large parts of Asia and what we'd now consider Europe; in addition to the Buddhist philosophical text, Menander and his reputation were also known to chroniclers of Greek and Roman history in the Mediterranean. Regardless of attempting to evaluating importance, or usefullness, or even morality, the Indo-Greeks and Greco-Bactrians still produced figures respected across an enormous swathe of the world's surface. That is not, I feel, a pair of cultures that sunk gently into the night without pride, achievement, or incident. | [
"After the death of Menander (c. 130 BC), the Kingdom appears to have fragmented, with several 'kings' attested contemporaneously in different regions. This inevitably weakened the Greek position, and territory seems to have been lost progressively. Around 70 BC, the western regions of Arachosia and Paropamisadae w... |
what, if any, consensus is there on michael jackson's multiple charges of alleged child molestation? | The evidence is really much the same as it was before, which is to say that there is not enough evidence to convict someone beyond a reasonable doubt. | [
"In 2005, Jackson was criminally tried for several counts of child molestation charges following concerns raised in the 2003 documentary \"Living with Michael Jackson\". He was seen holding hands in the documentary with 12-year-old Gavin Arvizo and talked about sharing a bed. Jackson was acquitted of all charges. I... |
what causes the "helicopter blades" sound effect when i'm driving down the freeway at a certain speed with a window open a certain amount? | Pressure oscillations. The incoming air compresses the air inside the cab. But because of inertia of the moving air, it compresses it more than the air in the cab can handle, so the inside air rebounds like a spring.
This happens over and over and you get the whup-whup-whup-whup of the oscillation.
| [
"HSI noise is caused by transonic flow shock formation on the advancing rotor blade, and is distinct from loading noise. The source of HSI noise is the flow volume around the advancing blade tip, hence it cannot be captured by examining only the acoustic sources on the surface of the blade, HSI noise is typically d... |
How do we determine the habitable zone of a star that is lightyears away? | We can calculate the average temperature of a planet given its size, [albedo](_URL_0_), distance from the star and the star's luminosity. The habitable zone is simply defined as the range of radii in which water would be liquid at this temperature. | [
"The habitable zone for this star, defined as the locations where liquid water could be present on an Earth-like planet, is at a radius of 0.26–0.56 AU, where 1 AU is the average distance from the Earth to the Sun.\n",
"The habitable zone for this star, defined as the locations where liquid water could be present... |
When and how came humans to the concept of right and left? | There are actually cultures, because of their language, that do not use left, right, etc. and only use cardinal directions, like North, South, etc.
One of these is an aboriginal tribe that speak,"Guugu Yimithirr".
A bunch of deaf kids in Nicaragua invented their own sign language that didn't include terms for left and right as well. | [
"The terms \"left\" and \"right\" were not used to refer to political ideology per se, but only to seating in the legislature. After 1848, the main opposing camps were the \"democratic socialists\" and the \"reactionaries\" who used red and white flags to identify their party affiliation. With the establishment of ... |
Has a childless hereditary ruler ever died while his wife was pregnant? | Succession laws [were not uniform across medieval Europe](_URL_0_).
Disclaimer: not a historian. | [
"If the King were to die without a male Heir his wife not being pregnant, or if she were pregnant but the pregnancy was not to result in an Heir to the Throne, then the Crown would be retained by His Royal Highness Prince Al-Hassan Al-Rida who would become the origin of future successions to continue through His li... |
where exactly is dna? | So DNA it's in the nucleus of a cell, all of the Eukaryotic organisms, that's all of the animals, plants, fungi, have their DNA stored in the nucleus, think of DNA as a really long wire, actually 3 football fields kind of big (if my genetics professor is to be believed) and it's super thin, all of that encodes the proteins you make, (that process is long enough for a ELI5) that chain is compressed around specialized proteins, think something like how tape is stored, and that super compressed thing is stored inside the nucleus of the cell, the thing about DNA is that you don't produce or change it, just like an old cassette tape your body reads from it on how to make your proteins, now about Cariotype (DNA photos) what you see there is Chromosomes, when a cell is dividing out has to make a duplicate of the entire DNA, so both the new cells have the exact same DNA when the cell is ready to divide the huge DNA chain gets cut and arranged in these kind of structures that help with the division process and that makes it so both cells get the same pieces of DNA | [
"Natural DNA is a molecule carrying the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one ... |
why does someone get cold right after turning off the shower, but can be out in real cold weather when out of a jacuzzi? | As someone who spent part of a winter vacation in an outdoor hot tub in Garmisch, Germany... it's still ridiculously cold when you get out. | [
"Water left stagnant in the pipes of showers can be contaminated with pathogens that become airborne when the shower is turned on. If a shower has not been used for some time, it should be left to run at a hot temperature for a few minutes before use.\n",
"If, for example, someone flushes a toilet while the showe... |
how is it so many poor countries are expensive. | I'm pretty sure it's not normal to "eat out" outside the US. It's for rich people and tourists. | [
"BULLET::::- Probably the main economic benefit that workers in rich countries obtain directly from poor countries is cheap consumer goods, but in fact the monetary value of these goods is statistically only a small part of their \"total\" budget. The big ticket foreign-made items in working class budgets are forei... |
Why do dispersion affects differents colours in different ways? | Frequency cannot change at an interface, that would mean you have a discontinuity in energy flow. See for example an animation like this:
_URL_1_
If frequency changed at an interface then the black lines, representing a maximum of the electric field and thus a maximum in the energy of the wave, would be discontinuous implying energy "jump somewhere else in space". If the material does absorb energy from the way that would be reflected as a reduction in amplitude (i.e the height of the maximum) not a discontinuity.
Beyond that are you asking why materials don't have the same dispersion as a vacuum? The dirty secret truth is that light doesn't propagate through a medium at all. Rather, when an oscillating electromagnetic field is applied at the boundary of a material (i.e. light impinges on it) this INDUCES an electrical excitation in the material which carries the energy of the light but is a composite object that depends on the material properties of how a given material polarizes in the face of an applied field. A cartoony animation like this maybe helps:
_URL_0_
The thing that is moving in the thick black line ISN"T an oscillating electric field, rather it is a new object that is the combined effect of an electric field AND the material dependent polarization of the atoms in the material. Now, there are conservation laws for what must happen at such an interface so the new object does inherit some aspects of the original light, but for example although it may have the same momentum it need not have the same direction (refraction) or speed as it ripples its way through the material. What electrical polarization ripple a material accepts is a material dependent property. | [
"The most commonly seen consequence of dispersion in optics is the separation of white light into a color spectrum by a prism. From Snell's law it can be seen that the angle of refraction of light in a prism depends on the refractive index of the prism material. Since that refractive index varies with wavelength, i... |
What did Pre-Columbian Native America trade routes look like? Where were they, what goods did they carry, how far were goods traded, and who did the traveling along with the goods? | While you wait for an answer you might be interested in the ["Pre-Columbian Trade and Contact"](_URL_1_) section of our [FAQ on Native American History](_URL_3_).
In particular, you may be interested in [this answer](_URL_2_) by myself, /u/Mictlantecuhtli and /u/retarredroof, [this answer](_URL_4_) by /u/Cozijo, and [this answer](_URL_0_) by myself. | [
"There is common academic agreement that significant systems of trading existed between the cultures of Mesoamerica, Aridoamerica and the American Southwest, and the architectural remains and artifacts share a commonality of knowledge attributed to this trade network. The routes stretched far into Mesoamerica and r... |
can a rigid blimp only be inflated with hydrogen, or will helium work too? | Both will work. Hydrogen will work better because it can fill the same volume with less weight, but it will also be worse because it is prone to explosions when exposed to oxygen and sources of ignition (see: Hindenburg).
Helium is preferred when available, but in the Hindenburg's case the Germans were not able to secure enough helium to fill the craft so they redesigned the airship to use hydrogen instead. | [
"Methane (density 0.716 g/L at STP, average molecular mass 16.04 g/mol), the main component of natural gas, is sometimes used as a lift gas when hydrogen and helium are not available. It has the advantage of not leaking through balloon walls as rapidly as the smaller molecules of hydrogen and helium. Many lighter-t... |
why do so many public drinking fountains just dribble water out? | low water pressure. the lower fountain works better because the pipe supplying the water is shorter, so it has less distance to travel. | [
"Drinking fountains are used especially during the summer, yet a lot of people are reluctant to drink the water due to fear of disease. According to the Public Health Office of Slovakia (), all drinking water fountains supply the same tap water as residents have in their homes and the water is safe to drink. Drinki... |
what is the purpose of the "circular net" in front of microphones of recording studios? | Pop filter. Stops bilabial sounds like "b" or "p" from sounding like loud pops. If you've ever heard a low quality youtube video, you know the pop I mean. Basically it smooths out the audio. | [
"A microphone splitter is a device with an input from a microphone and multiple outputs. It is also known as a \"rathouse\" due to the large amount of cabling involved. A splitter is often used at larger venues to provide feeds from microphones or other sources to both a front of house mixing desk and a monitor des... |
why is ireland not united? and do most irish want it to be? | There has been about 100 years of fighting over this very question.
Very simplified history here:
Northern Ireland was created in 1921 after an uprising of Irish Republicans lead to a peace treaty between Ireland and the UK which partitioned the country between the Irish Free State (later the Republic of Ireland) which was mostly Catholic and Northern Ireland, which is made up of 6 or the 9 counties of Ulster, and has a majority Protestant population loyal to Britain.
In Northern Ireland there is also a large Catholic population that has been historically oppressed and identify themselves as Irish and not British (as the protestants do). This sectarian divide is typically described as Nationalist/Republican for the Catholic and Loyalist/Unionist for the protestants.
Through much of the 70's and into the 90's there were wide ranging conflicts between these two groups which are known as the troubles. This is where the traditional image of the IRA, amongst other paramilitary groups comes from, though the IRA has been around in multiple different forms since the uprising that lead to the creation of the Free State.
In 1994, the Provisional IRA issued a cease fire, and in 1998, the Good Friday Agreement was signed, that ostensibly ended the troubles (for the most part). However, there have been instances were splinter groups have disregarded the cease fires (the Omagh bombing for one), but for the most part the major conflicts of the Troubles are in the past. Though there is still some sectarian uprisings traditionally coinciding with the Protestant Marching Season and a recent uproar over the flying of the Irish flag over official buildings (the Union Jack is also still flown).
For you other questions, traditionally the majority of the people of Northern Ireland have wished to remain as part of the UK, though again much of this support comes from the protestant majority, though in recent polls, even a large number of Catholics wish to remain, which could be a result of the recent economic troubles in the Republic. The UK certainly doesn't keep NI for tax purposes as it typically costs the UK far more than it generates in tax income, as unemployment is pretty high.
| [
"United Ireland (also referred to as Irish reunification) is the proposition that all of Ireland should be a single sovereign state. At present, the island is divided politically; the sovereign Republic of Ireland has jurisdiction over the majority of Ireland, while Northern Ireland is part of the United Kingdom. A... |
Who was enslaving and who was trading 6th century Anglo-Saxons? | So while the exact veracity of this anecdote is impossible to verify, I can talk a little bit about the slave trade in Northern Europe at this time in history.
Slavery was an integral part of the Anglo-Saxon world, as well as other cultures and groups in the North Sea world. Scandinavians, Saxons, Frisians, the Irish, Romans, Franks, and so on all engaged in the slave trade, and would continue it for several centuries. It was not outlawed in England until 1102. At this point its likely that most slaves were captured in raids or the small scale wars that were endemic to Europe at this time. Ireland in particular was a common source for slaves, though England was also the site of depredations by Scandinavians as well.
The slave trade also was quite profitable and prevalent in the Mediterranean world as well. However the Mediterranean economy had undergone a shift, and radical downsizing, in the centuries following the collapse in Roman authority in the west. Slaves were still commonly found in markets in Italy especially but were often sources from what is today the Balkans.
Scholars have identified the shift in western Europe's trade network from the broader Mediterranean world to a North/South Axis from Scandinavia down the Rhine towards the Alps. So it is unlikely that large numbers of slaves were being moved from England down to Rome for sale. The supply of slaves in Italy came from elsewhere and the long distance trade of the Roman empire had failed some time in the past. So the exact truth of this anecdote is somewhat suspect.
Slaves were taken by many different groups at this time, and we should try to not ethnicize the slave trade in the Medieval world. Although the white skin of the Angles is played into their need for salvation, slavery, and the slave trade, were not restricted by ethnicity or religion at this time. | [
"As German rulers of Saxon dynasties took over the enslavement (and slave trade) of Slavs in the 10th century, Jewish merchants bought slaves at the Elbe, sending caravans into the valley of the Rhine. Many of these slaves were taken to Verdun, which had close trade relations with Spain. Many would be castrated and... |
Why do we freeze for a split second when something startles us or makes us jump? | The freezing response is mediated by a circuit involving the amygdala and a part of the brainstem, the periaqueductal gray. This circuit can coordinate the typical motor output: freezing, jumping, yelping, etc.
Anyone can come up with plausible-sounding evolutionary "explanations," but this can easily spiral into just-so storytelling. **An evolutionary story that sounds good or "makes sense" is not a substitute for data.** The important part is the (comparative) neuroanatomy and behavior.
Edit: there was a removed comment that asked whether "why" questions are even answerable. Here is the response I was typing before it was removed:
> We can answer "little" why: the mechanics of what happens, the steps, the neural substrates, the behavior, etc.
>
> It is much harder to answer the "big" why: what genetic, developmental, and environmental factors triggered the appearance, prevalence, and conservation of a particular neural circuit and behavior in a mammalian ancestor millions of years ago. | [
"Freezing behavior or the freeze response is a reaction to specific stimuli, most commonly observed in prey animals. When a prey animal has been caught and completely overcome by the predator, it may respond by \"freezing up\" of in other words by staying complety still. Studies typically assess a conditioned freez... |
How did the people of England respond to the Declaration of Independence? | I read a paper a while ago from Stephen Conway that deals with changing perceptions of the relationship between Britain and the Thirteen Colonies during and after the War of Independence. Bear in mind that while his perspective is useful in answering your question, it may not represent the full picture.
_URL_0_
Essentially, Conway argues that the British recognition of "Americans" as a distinct people (and not merely British colonials) had little to do with the Declaration of Independence, and that in general, the Declaration did not provoke a lot of response from the British public at the time. He surveys British newspapers in the weeks following the Declaration, and notes that while it was widely printed in Britain, it was rarely given prominence or commentary. The amount of response in the British press, whether in papers or in pamphlets was "unusually" small.
Conway attributes this general lack of interest to the fact that the actual event of the Declaration was not a surprise, and that in comparison to the treason of armed insurrection, the assertion of national independence seemed relatively minor. Government correspondence also indicates that the war, at this point, was still discussed in the language of rebellion, which is to say that the Declaration did not cause either the British public or the British government to regard colonists as anything but dissident British colonials with treasonous leaders.
On the other hand, those in favour of a conciliatory approach within Britain do seem to have been worried that the Declaration diminished the strength of their arguments, because it clearly outlined American claims to independence, not just to rights as British subjects. But ultimately, Conway comes back to his argument that while the assertions contained in the Declaration of Independence did attract the attention of the British public, the document itself did not - mostly because the ideas contained therein were already known to the British public. As such, it was not one of the motivating factors behind a British (or American) recognition of Americans as a separate people. | [
"The United States Declaration of Independence was approved there on July 4, 1776, and the Declaration was read aloud to the public in the area now known as Independence Square. This document unified the colonies in North America who declared themselves independent of the Kingdom of Great Britain and explained thei... |
why do snail shells grow with them, but hermit crabs have to keep trading up? | Snail shells are actually a part of the snail. The more calcium they eat, the quicker they grow. Hermit crabs aren’t born with a shell, so they have to move into a new one as they grow | [
"As the hermit crabs grow, they must exchange their shell for a larger one. Since intact gastropod shells are not an unlimited resource, there is frequently strong competition for the available shells, with hermit crabs fighting over shells. The availability of empty shells depends on the abundance of the gastropod... |
I was once watching a TV documentary about Rome with my dad. One of the experts started to talk about the orderly way Romans did combat, my dad turn to me & said it reminded him of how the riot police used to operate back when he was one in the 1980s. Is it just a confidence the two are similar? | I'm not really sure what you are asking. Are you asking if modern riot tactics can be traced back to the idea of a body of infantry moving as a tight group? Or are you asking if modern riot tactics are deliberately modeled after Roman formations, as in someone sat down and said "let's emulate Roman heavy infantry on purpose"?
The vague and broad idea of infantry with shields fighting as a group is hardly revolutionary and clearly predates the Romans. I know a have a book at home dealing with modern law enforcement the and crowd control that focuses on major riots and civil disturbances over the last fifty years or so, I'll see if I can find anything there about the origins of specific tactics used by riot police and see if there's any clear indicator people tried to emulate the Romans. | [
"The film focuses on the life of a group of riot control force policemen, the \"Celerini\", and their life in Rome \"cleansing\" stadiums of Ultras, public demonstrations, evictions and everyday family life.\n",
"BULLET::::- \"Rome\": A historical drama set in Ancient Rome that primarily chronicles the lives and ... |
How thick does a layer of gold need to be to be fully opaque? | Gold has a resistivity of about 2.44 x 10^-8 ohm-meters. Visible light has frequencies between about 400 and 700 THz. So, using a [skin depth calculator](_URL_0_) the skin depth is only a few nm. For "fully opaque" you probably want somewhere between 3 and 5 skin depths.
So 100 nm is probably overkill. They might have just used that number because it's what their deposition process can reliably produce. | [
"Very thin crystals of MoTe can be made using sticky tape. When they are thin around 500 nm thick red light can be transmitted. Even thinner layers can be orange or transparent. An absorption edge occurs in the spectrum with wavelengths longer than 6720 Å transmitted and shorter wavelengths heavily attenuated. At 7... |
how small is an atom? | There are more atoms in a grain of sand than there are grains of sand on every beach on earth.
I feel using anything but an analogy makes it very hard to understand | [
"Atomic dimensions are thousands of times smaller than the wavelengths of light (400–700 nm) so they cannot be viewed using an optical microscope. However, individual atoms can be observed using a scanning tunneling microscope. To visualize the minuteness of the atom, consider that a typical human hair is about 1 m... |
How did wrestling become staged? | Wrestling has a long history in Europe, going back to Ancient Greece where wrestling was a pretty popular sport in the Olympiads and it continued on throughout history Early Modern Era, Modern Era, etc. Although very different wrestling from what we think of when we think "wrestling", and I mean in both the staged version "pro wrestling" and the real athletic version "amateur wrestling". It naturally came to America and really a whole culture of professional sports in American began to take off around the 1800s. Specifically Irish immigrants helped bring a more recognizable form of wrestling known as "[collar and elbow](_URL_0_)" This is where the contestants lock up with their hands around each others shoulders, and if you watch pro-wrestling you'll instantly recognize this hold as this is how most pro-wrestling matches begin.
After the civil war the popularity of this style of wrestling began to spread, and became sort of a popular sport in Union camps during the actual war, and just in general organized sports began to take off in the post war age and specifically the gilded age when large amounts of lower class to middle class city dwelling people began to have the time and disposable income to actually view organized sports. Wrestling during this time was generally a "sideshow" act and wrestlers would often be men with some form of training going with circuses and touring putting on matches. During this time one of the first real wrestlers came about, his name was James McLaughlin and he travelled around Europe and the USA putting on matches and sometimes commanding around 1,000 $ per match. Wrestling during this time was not fake, and was quite brutal with McLaughlin supposedly killing two of his opponents.
Around the late 1800s "Greco-Roman" wrestling became more popular, it banned all holds below the waist and was generally closer to actual wrestling as opposed to the older collar and elbow which was more of a bare-knuckle style brawl then an actual wrestling match. The new style generally required more muscular contestants as opposed to the older collar and elbow which requried smaller, more agile fighters.
Next came a wrestler named William Muldoon, he was a Greco-Roman style fighter, his importance is that he created an actual championship belt and actually gave other fighters in the sport something to try and achieve as opposed to just going from fight to fight for a couple bucks. For this he's gained the title "father of modern American wrestling". Around this time a new style called "[catch wrestling](_URL_1_)" which is more submission based wrestling. Its funny that around this time wrestling was considered a more real sport than boxing, which had several famous scandals around it that involved fixing fights; obviously the roles would soon change, but for the moment wrestling was seen as the more real sport.
So the question then becomes how did the sport become a work?
Well wrestling began to fade in popularity as an actual sport, it was still entertaining but the rise of baseball and football decreased wrestling's appeal as an actual sport. So wrestlers began to make less money and thus they had to tour more and fight more matches. So men like Muldoon, hoping to keep their fame and title, would often work behind the scenes to make sure certain wrestlers won and time limits were instituted to keep older wrestlers from losing long matches to younger opponents. Furthermore wrestling in carnivals became popular and what would happen there is a promoter would offer to pay money to anyone who could beat a certain strong wrestler. Obviously in order to make money they would have to present the wrestler as beatable and thus they would have certain "plants" in the audience who the wrestler would get beaten by. This carnival style of wrestling would be an important training ground for future wrestlers in the early/middle 20th century. Carnival wrestling is also why wrestlers use the term "mark" to refer to wrestling fans, since perspective customers in a carnival are referred to as marks.
This carnival wrestling became popular and wrestlers and promoters alike saw that they needed to keep the audience interested and in order to do that they needed to keep up the illusion that outcomes were legitimate. So wrestlers began to become secretive and very protective of the business, especially when dealing with outsiders. They adopted a form a slang, mostly derived from pig Latin when dealing with outsiders. From this we get the term "Kayfabe". For those who don't know, Kayfabe refers to the staged nature of wrestling, to "keep Kayfabe" is to keep the true nature of the wrestling business secret and pretend that what's happening in the ring is actually real. While the Wikipedia page for Kayfabe says that:
> Though the general public had been aware of the staged nature of professional wrestling for decades,
I would heavily disagree with that, Kayfaybe was generally kept quite strong until the 80s, especially in the southern territories of the USA where wrestling was very popular. In bigger, Northern cities it was a bit harder to keep it secret, but in more rural areas like Tennessee, Florida, the Carolinas, etc. Kayfaybe was quite strong and wrestlers were very protective of the business. For those who are interested look up some older wrestling stories from the 70s and 80s and look at what some older wrestlers did to keep Kayfaybe . Jim Cornette, a relatively well known wrestling figure in the 80s and 90s told a story about how he met two wrestlers in an amusement park. Now in the story lines these wrestlers and Cornette were "fighting" so Cornette immediately ran out of the amusement park because they threatened to beat him up in the middle of a huge crowd. The farther you go back the more hilarious it gets. There were some wrestlers in the 30s who nearly got in huge trouble because they refused to testify in court because it would have exposed the business. And the fans took it seriously too, when famous wrestler "Sgt. Slaughter" became a bad guy in the 90s he played a character that was an Iraqi sympathizer (I know). And he had to have full times body guards because he was so hated, some people legitimately thought he was an actual Iraqi sympathizer.
Finally kayfabe came to an official end in 1989 when Vince McMahon acknowledged in a court hearing that wrestling was fake in order to get out of paying taxes that other sports like boxing had to pay. Wrestling has since entered a "reality era" where its more akin to acting; wrestlers openly break character as soon as they step out of the ring; something that would have been unthinkable nearly 20 years prior.
So to give a quick recap, it became fixed when carnival style wrestling became far popular than the more sports style wrestling that had been popular before.
The best source for this is "Ringside: A History of
Professional Wrestling in
America" by Scott Beekman
| [
"Professional wrestling, in the sense of traveling performers paid for mass entertainment in staged matches, began in the post-Civil War period in the late 1860s and 1870s. During this time, wrestlers were often athletes with amateur wrestling experience who competed at traveling carnivals with carnies working as t... |
what has caused such a divide between u.s. citizens and their police force? | An uneducated public who only reads 144 character tweets for the entire story. A lack of understanding that a few officers fucking up doesn't make us all evil, heartless, bastards with a God complex.
The medias refusal to show POSITIVE stories and constant push to make every single story negative or "juicy" or racial; even if such an undertone doesn't exist
A pissed off police force who feels like Vietnam vets when they came home. Not saying we have the same war horror stories but the reaction many people have to our presence and existence. | [
"Concerns about the militarization of police have been raised by both ends of the political spectrum in the United States, with both the right-of-center/libertarian Cato Institute and the left-of-center American Civil Liberties Union voicing criticisms of the practice. The Fraternal Order of Police has spoken out i... |
why do humans hear a musical "beat" in repetitive sounds? | The human brain is highly adapted to pattern recognition. Our neurons like to overlay “filters” over things to see patterns from random noise. Do a repetitive sound will sound like a beat and rows of different colours look like stripes. | [
"Music is the only form of communication that saves us from an overwhelming amount of small talk. This is not only a human phenomenon, but happens throughout the animal world. Thomas makes examples of animals from termites and earthworms to gorillas and alligators that perform some sort of rhythmic noise making tha... |
how come the human genetic code can fit roughly in ~1.5gb of data yet we turn out such complex organisms? furthermore, the code that separates us from other mammals can fit on o floppy disk. | A few key differences between the genetic sequence and a computer sequence:
1. Computers run in binary. Genes run in quaternary (4 types of nucleic acids). That immediately increases the amount of data you can store exponentially. One step further, gene sequences build amino acids. There are 21 total amino acids that can form thousands of different proteins.
2. People are made of matter. Matter is comprised of 120-something (the number keeps changing) different elements, each with unique interaction with each other and interactions with groups of other elements, which is even more information than a simple quaternary system. Electricity, on the other hand, is not matter.
There are various theories about coding data in different voltages or currents or whatever to allow electricity to provide more than a binary system, but we don't have the technology yet (and it may not even be possible). | [
"In many species, only a small fraction of the total sequence of the genome encodes protein. For example, only about 1.5% of the human genome consists of protein-coding exons, with over 50% of human DNA consisting of non-coding repetitive sequences. The reasons for the presence of so much noncoding DNA in eukaryoti... |
why didn't evolution make females just as 'horny' as men. | as far as i know women are just as horny as men. evolution is great, isnt it? | [
"Male animals are typically more elaborately ornamented than females. The classic sexual selection theory notes that because sperm are cheaper to produce than eggs, and because males generally compete more intensely for reproductive opportunities and invest less in parental care than females, males can obtain great... |
the difference between pixel- and vector-based images | Raster images (those made up of pixels) have a fixed size. It's like taking a piece of graph paper and coloring in the squares. If you want to make a picture bigger, you only have as much information as was in the original pixels. This makes the image blocky or fuzzy when you zoom in or try to blow it up.
Vector images, OTOH, are made up of lines and curves that are mathematically defined. If you ever want to change the size, the vector engine recomputes things. You can scale vector images 'perfectly' at any scale.
Raster images are easier to display & better at capturing photographic detail. Vector images can be significantly more work to create. | [
"As opposed to the raster image formats above (where the data describes the characteristics of each individual pixel), vector image formats contain a geometric description which can be rendered smoothly at any desired display size.\n",
"Vector graphics formats are complementary to raster graphics. Raster graphics... |
how does an artist “go platinum” in today’s world of spotify/apple music? | They changed the rules for platinum, so now a certain number of digital track purchases, or a larger number of digital on-demand plays, counts as equal to 1 album sale. | [
"In a June interview with Hypebot, Wallach reported that $180 million of royalties was paid out in 2011 and 70% of Spotify's revenue consisted of royalty payments. Spotify's growth meant that the per-stream royalty rate doubled between the service's inception and mid-2012. He said that, at the time, compared to iTu... |
why does everyone believe everything snowden leaks as truth? | When Snowden started releasing information, the US government got very upset. You know how sometimes you get upset, even though you don't mean to? Usually it's because there is some truth there. If somebody said something ridiculous, like your brother is a raptor, you wouldn't be mad because you can prove it's not true. Now if they said sometimes you eat boogers when you think nobody is watching, you might be upset and tell them to shut up, because you do eat boogers sometimes and if you do it again I'm sending you to bed. | [
"In the aftermath of Snowden's revelations, The Pentagon concluded that Snowden committed the biggest theft of U.S. secrets in the history of the United States. In Australia, the coalition government described the leaks as the most damaging blow dealt to Australian intelligence in history. Sir David Omand, a former... |
What were Nazi Germany's plans post-WWII in the case of an (unlikely) Axis victory? | Territories in the east were to be governed as something like German colonial provinces called *Reichkommissariaten*, whose inhabitants would be mostly killed off by an engineered famine called the [Hunger Plan](_URL_0_), with the survivors being used as slave labour on German farms or forcibly relocated.
The Nazis planed to kill off a certain percentage of the inhabitants in different areas; 80-85% of Poles were to be exterminated, 50-60% of Russians, 50% of Czechs, 65% of Ukrainians etc. The survivors of some of the more "acceptable" ethnic groups like Czechs, Balts and Ukrainians would be forcibly "Germanized". Around 45 million of surviving Eastern Europeans who were not enslaved or starved to death were to be forcibly relocated into Western Siberia, leaving a "zone of settlement" in European Russia and Ukraine. Around 13 million were to remain as slave labour. The Nazis planned to relocate something like 10 million Germans (whether by force or willingly isn't clear) in this new *Lebensraum*, but this number was simply not feasible, hence the "Germanization" of some of the other ethnic groups. Some writers believe the sterilization experiments done in concentration camps were meant to be implemented on the general population in occupied areas of the east. They planned this all to happen in a timeframe of around 20 years from the 1940s. For more on this topic, look up "Generalplan Ost" - the Nazis kept very meticulous details about their plans.
Nothing like this was planned for the West. IIRC, Hitler wanted some sort of European commonwealth, like a Fascist version of the EU, and his occupation of the west was supposed to be temporary - he seemed to have no problem recruiting collaborators from the various reactionaries of western Europe. There were no plans that I am aware of for the extermination of Frenchmen or Britons. He originally wanted to ally with Britain (for ridiculous 'racialist' reasons) against the USSR, and would have allowed them to maintain their colonial empire in exchange for his European empire. Nazi Germany didn't really want to conquer the world; they wanted a huge empire in eastern Europe purged of its Slavic and Jewish inhabitants, to make way for a huge German settler population that didn't really exist. | [
"With the signing of the Tripartite Pact on September 27, 1940, creating the Axis of Germany, Japan, and Italy, Decoux had new grounds for worry: the Germans could pressure the homeland to support their ally, Japan.\n",
"In February 1942, Raeder presented Hitler with the \"Great Plan\", a grand strategic design f... |
fast fourier transform (fft), and/or discrete fourier transform | Not sure if you're after an explanation of what it does or how it works - I don't think I quite get the maths enough to explain the latter....
I always think about an orchestra. If you have never heard any of the instruments before when you listen to the orchestra you will still hear the sound they make but they're all mixed in together. An expert, though, would be able to pick out the sound of individual instruments and understand the sound they are contributing to the greater whole. They could, for instance, describe the notes that the flutes are playing. A Fourier transform does this sort of thing - it can take a complicated, convoluted mess of signals and separate out the individual components that make up that mess. It would be like recording an orchestra concert and being able to listen back to each individual instrument separately.
Apologies if you were after something far more in-depth! | [
"A fast Fourier transform (FFT) is an algorithm that computes the discrete Fourier transform (DFT) of a sequence, or its inverse (IDFT). Fourier analysis converts a signal from its original domain (often time or space) to a representation in the frequency domain and vice versa. The DFT is obtained by decomposing a ... |
the reason and use of the serial numbers on cash bills/currencies and why coins do not have such | The printers on currency use the numbers to keep track of how much is printed, so workers can't wander off with some of the product. Coins are heavy, and the amount that could be pocketed wouldn't be worth nearly as much. | [
"In contracts and other documents, the numbers written were not actual numbers of the coins, but their value in a standard system: for example, the standard often used the gold system, but the payments were done with the local silver coins. \n",
"The first U.S. currency with a series year was printed on United St... |
how/why do migraines make your eyes extremely sensitive to light? | Migraine sufferers have a problem with a specific part of the nervous system the opthalmic division of the trigeminal nerve that causes pain around the eye.
Eli5 translation: The brain has 12 major wires. And one specific wire(trigeminal) which also has small wires connected to it: opthalmic(around the eye), mandibular(jaw) and maxillary(lower face). The opthalmic wire has a short(like flickering electricity) that results to pain and light sensitivity.
My bad /u/TheManRedeemed | [
"Some studies attribute migraine headaches to overly intense light, while others linked it with certain spectral distributions. In one survey bright light was the number two trigger (affecting 47% of respondents) for causing a migraine episode. \n",
"These cause permanent obstruction of aqueous outflow. In some c... |
Was the Holocaust rational enlightenment carried out to its most twisted ends? | > I feel as though the Holocaust has its roots in something other than antipathy towards Jewish people.
Why do you feel this way? What's your justification for this idea?
> I can elaborate on this more,
You should - as it is, it doesn't really follow at all.
> but placing more blame on the enlightenment helps me sleep easier at night.
Unfortunately, historical analysis doesn't work this way. What makes us more comfortable is really irrelevant.
| [
"In their analysis of contemporary western society, \"Dialectic of Enlightenment\" (1944, revised 1947), Theodor Adorno and Max Horkheimer developed a wide and pessimistic concept of enlightenment. In their analysis, enlightenment had its dark side: while trying to abolish superstition and myths by 'foundationalist... |
What's the earliest recorded condemnation of racism anywhere in the world? | From Muhammad's final sermon, March 9th 632
**"Indeed, there is no superiority of an Arab over a non-Arab, nor of a non-Arab over an Arab, nor of a white over a black, nor a black over a white, except by taqwa (piety). "**
Tirmidhi Hadith, Hadith #159
It is a fairly concise sermon, focused on giving advice to the Muslims before Muhammad's passing, but this section pertains to what your question was. | [
"Francisco Bethencourt is Charles Boxer professor at King's College London. Bethencourt's research centres on the history of racism, Portuguese and European expansion from the 15th to the 19th centuries, missions and religious history in the Catholic world, and identities and cultural exchange in Iberia. Bethencour... |
With advances in many fields of Medicine including the transplant of synthetic hearts and 3d printing of various body parts making cheap prosthetics possible, why haven't we seen significant advances in prosthetic cartilage for damaged joints and herniated disks? | Ok, first things first :
The synthethic hearts are not too good. In most cases they are used as "bridge-to-transplant" solution, not as an endgame. People don't survive too long on them. Also 3d printing body parts is highly experimental and pretty far from being a standard.
Now, yes we do use mechanical heart valves. They are pretty good. You have to take anti-koagulation medication for the rest of your life, but otherwise you are not really handicapped.
Mechanical knee/hip/shoulder/etc replacements are pretty okay as well. You can't do sports with them, but they enable you to live a painless life, which is a pretty big deal for a patient with osteoporosis.
Now, when we replace joints, we don't manufacture human-like structures. We basically build something out of metal, that works like the original, without actually being *like* the original.
Heart valves now are waaaaaaaaay simpler structures as joints or even cartilage. They are basically a few layers of cells that passively move. They don't have vessels, they don't regenerate, they have a very reduced metabolism (low turn over tissue). It's probably the easiest thing in the whole human to replace.
Cartilage on the other hand is a highly complicated tissue. It's capable of expanding and compressing, balancing the pressure of our whole body weight (and more, when you do movements like jumping). It's capable of storing water when under low pressure, and releasing it when the pressure rises, and various other things.
Manufacturing something like this is far beyond our current knowledge and technical abilities. | [
"3D printing for the manufacturing of artificial organs has been a major topic of study in biological engineering. As the rapid manufacturing techniques entailed by 3D printing become increasingly efficient, their applicability in artificial organ synthesis has grown more evident. Some of the primary benefits of 3D... |
why/how one can hear the voices of the actors on a tv show/movie so clearly without any extraneous noises in the background. can it really all be edited out? | The actors have mics following them everywhere on the set. The mics pick up the dialogue and from the tape made, the sound man can edit out background noises and modify the actor's voice. The recordings are made in multiple tracks and fixing the voices is not much different than how artists record songs.
When you see shows where say someone is flying in a chopper and you can hear the pilot speaking normally, the sounds of the chopper are edited out using noise cancelling software. | [
"In film, the filmmaker places the sound of a human voice (or voices) over images shown on the screen that may or may not be related to the words that are being spoken. Consequently, voiceovers are sometimes used to create ironic counterpoint. Also, sometimes they can be random voices not directly connected to the ... |
What would it look like if I constructed a cube made of one-way mirrors, so a person could see into the cube but the inner walls were reflective? | The way one-way mirrors works is that the glass reflects part of the light, while transmitting some. This work _both ways_. The reason it _acts_ as a one-way mirror is because the side that looks like a mirror is much brighter than the other side. (For example, the interrogation room is brightly lit, while the observation room is dark. Those inside the interrogation room looks at the glass and see their own reflection.) The bright light means that lots of light is reflected, and the intensity of reflected light is much higher than light transmitted from the dark room.
So, you need to put in a light source inside the box, and look at the box in a dark environment. What you will see is similar to what it looks like if you have a cube made of mirrors, except with one side replaced with plexiglass.
Edit: Something like [this](_URL_0_).
If it is reversed - the outside is brighter than the inside - then the cube will look like it is constructed of mirrors.
Like [this outdoor toilet](_URL_1_). | [
"There are also two pairs of mirrors in the museum, that are placed at an angle of 90 degrees in such a way that one cannot see one's own face but others can see. It was used by the Nawab to prevent predators from harming him, and was kept at a place so that the predator cannot see his face and think a mirror to be... |
What calendar is used for older dates? |
Practicing historian here. (Moving a lower level comment up and expanding some)
I work in the period both before and after the Gregorian calendar was adopted in the Spanish Empire (1582). Yes you could adjust dates for events occurring under the Julian calendar but then you would be using different dates than those found in the primary sources. Even though I work on both sides of the calendar reform, I never adjust dates. There is no reason to. The dates in the documents are correct.
Remember the switch from the Julian to the Gregorian Calendar ultimately involved skipping a specific number of days to account for drift in seasons since the establishment of the Julian system. The Julian calendar did not precisely account for drift caused by our calendar year of 365 days not mapping on to the actual orbital time of the earth. This means that the switch between the two calendars necessitated a skipping a head of days specific to the time in which the switch occurred. In 1582, the Spanish Empire skipped ahead 10 days in October of 1582. The English didn't switch until the mid 18th century by which point the calendars had drifted to 11 days difference. This also means that calculating a Julian date within the Gregorian system requires variable adjustments. Earlier dates, dates closer to the establishment of the Julian calendar require fewer days difference than modern dates which require more.
They only time it would make sense to adjust dates in a historical work would be when doing comparative history where one area understudy retained the Julian calendar while the other adopted the Gregorian. In that instance clarity might demand express correlations. A classic example is the death of Shakespeare and Cervantes, great authors of the late 16th century. Both died on April 23, 1616. Yet, they actually died 10 days apart. When Cervantes died the date in the Spanish Empire was Gregorian, and so 10 days before the day in which Shakespeare died in the Julian.
So to reiterate, historians use the date as recorded in the documents. If necessary adjustments can be made to help clarify in situations when dates between two places come from different calendars. Historians do not as a rule change Julian dates to Gregorian dates. The Battle of Tours occurred on October 10, 732. We do not adjust that a few days forward to be Oct. 14. | [
"A calendar era is the year numbering system used by a calendar. For example, the Gregorian calendar numbers its years in the Western Christian era (the Coptic Orthodox and Ethiopian Orthodox churches have their own Christian eras). The instant, date, or year from which time is marked is called the \"epoch\" of the... |
Where can I find a truly complete history of the British Isles? | The task is certainly massive. Just one comment, as you say there are many and based on my experience I find myself better off with a good generic history that typically would awake my interest in certain periods worth going deeper.
To start with? BBC has a good history program.
_URL_0_
Others may contribute something more scholarly and the resources/book list in the right menu of this Reddit page may be very helpful | [
"British Isles – A Natural History is an eight-part documentary series produced by the BBC Natural History Unit and presented by Alan Titchmarsh. Originally broadcast in the UK on BBC1 from September to November 2004, it took viewers on a journey from the formation of what is now the British Isles some 3 billion ye... |
Why do my leftovers stick if I don't wash my plate soon after eating? | The moisture in the leftovers kept them from adhering to the plate. When you leave it out, they dry up and stick to the surface.
Basically, on a very small scale your plate is not a smooth surface, it has peaks and valleys and such. With moist things like sauce, the food particles flow all over these peaks and valleys. As the water evaporates, such particles are no longer suspended and can't flow as easily, so they are sort of interlocked with the rough surface of your plate. This is why dry food like uncooked pasta doesn't just stick to dishes like tape.
Special materials like Teflon are engineered to minimize the surface contact between food and dish, thus making them much easier to clean. | [
"Regionally, the tradition varies from not wasting food on one's plate, to only eating what one feels like and leaving the rest. However, in some regions, leaving food as an offering is common; some consider this as a method of only wishing to consume pure spirits of the food and the discarded food will represent t... |
why 720p hd is 1280x720 but hdtvs are 1366x768 | 1024x768 panels already exist. It's cheaper to just cut them longer at 1366 than to make 720 ones. Most 720 screens seem to actually be 768. | [
"BULLET::::- First, the HDTV-standard 1280720 (otherwise commonly described as \"720p\"), which offers an exact 16:9 aspect with square pixels; naturally, it displays standard 720p HD video material without stretching or letterboxing and 1080i/1080p with a simple 2:3 downscale. This resolution has found some use in... |
how do major airports recover from mass flight cancellations? | It's not the airport that has to recover, it's the airlines. That makes a big difference and aids in explaining the issue.
Let's say Delta has one flight per day between two cities. On Monday, they cancel the flight, stranding 250 passengers. Tuesday's flight has 15 open seats, so they re-book 15 people. Their partner airline, Air France, has 11 open seats on the same route, so that's another 11 taken care of. This can easily snowball (though we're assuming two well-connected city pairs).
Now let's assume Delta's flight is the *only* flight each day. Well, Delta will ALWAYS have extra aircraft sitting around as spares (whether they're awaiting maintenance checks or because all airlines pad their schedules). Therefore, they can send one of these extra aircraft. For instance, let's say there's one flight per day from Atlanta to Boise, which gets canceled. But Delta also has a plane that sits in Atlanta all day awaiting a flight to Europe at night. They can then take this aircraft while it normally would have been sitting and run and a round-trip to Boise if needed.
Lastly, the airline can prioritize key flights to recover. Once the weather improves, the airline can ferry empty aircraft around its network to be ready for the next day and have planes where it needs them most (it may mean sacrificing other flights, but their dispatching and booking systems can handle this easily to determine which cancellations will have the fewest ripples).
TL:DR; There are tons of ways airlines make up the passenger load, from re-booking on other flights, to using other airlines, to bringing in other planes, and even hoping people cancel their plans altogether or change the of their own accord. | [
"Flights that have not departed their airport of origin will be delayed or cancelled. Airlines are required to manage their aircraft at all airports to minimize the impact to passengers affected by the ground stop.\n",
"The airport was supposed to be demolished to make way for a housing estate, but that plan was ... |
how does metadata work and what is written behind files? | Metadata depends on the file. For recordings, such as pictures and video, metadata will typically include things like date, time, and camera settings. Metadata in other files such as application ZIP files and movie files will often contain copyright, licensing, and distribution information.
Cameras, for instance, may store data within a video file about when it was taken, so that it can organize the files in the built-in video player based on when they were recorded. | [
"Metadata can be found in many types of files such as documents, spreadsheets, presentations, images, and audio files. They can include information such as details on the file authors, file creation and modification dates, location (GPS), document revision history, thumbnail images and comments.\n",
"Sometimes, m... |
what are the differences between the xbox one and ps4? | Sony is a hardware company.
Microsoft is a software company.
| [
"The PlayStation 4 (or PS4) is a video game console from Sony Computer Entertainment. Billed as the successor to the PlayStation 3, the PlayStation 4 was officially announced at a press conference on February 20, 2013. The fourth home console in Sony's PlayStation series, it was launched on November 15, 2013 in Nor... |
how solar power works, from the pv to the inverter and the lightbulb lighting up! | A PV cell converts light energy into DC electrical energy.
An inverter converts DC to AC, by switching the DC off and on 60 (or 50) times /second. It usually uses a transformer to convert the chopped AC to 120 (or 240) volts.
If you are using only DC you may not need an inverter, but most situations have one to convert the variable DC from the solar panel to a stable 12 volts DC.
You can't make your own. It requires ultra pure silicon, and lots of expensive equipment. | [
"Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. PV converts light into electric current using the pho... |
what is fantasy football and how is it different from video games and gambling? | Fantasy football is not like a video game mainly because you don't physically play. It is a lot like betting on horse races. In the beginning of the season you join a league. With friends or with random people. There may be a buy in or some other kind of ante or there might not. You then draft football players. There are different draft rules but those aren't important for a general understanding. You each take turns picking players who you think will do well in the upcoming season. If you think tom Brady is going to have a good year you might draft him as your QB for example. After you have your players you get matched up to play a theoretical game with the players that you drafted agaisnt the players that your opponent drafted. Based on how the drafted players perform IRL they are assigned a point value. After Monday night football the person with the higher point total wins. You then go up agaisnt another person in your league, so on and so forth until you come to the end or the season and depending on your leagues rules there may be a playoff with one winner who gets all the players buy ins. Between each match up and during the week you have the opportunity to trade players and chose your starting lineup based on how players are performing during the season. Hope this kind of helps. Mind the formatting this is from mobile. | [
"Fantasy football is a genre of board game or wargame which normally involves two teams of fantasy races (such as elves, dwarves or orcs) competing in an extremely violent variant of gridiron football. Often the only resemblance to gridiron football for many fantasy football games is to get the ball into an end zon... |
how can we listen to the sound of two black holes colliding if there is no sound in space? | That sound was generated based on other emissions, and is an artificial approximation. Think "how it could be heard if that was sound waves" kind of thing. | [
"A sonic black hole, sometimes called a dumb hole, is a phenomenon in which phonons (sound perturbations) are unable to escape from a fluid that is flowing more quickly than the local speed of sound. They are called sonic, or acoustic, black holes because these trapped phonons are analogous to light in astrophysica... |
What happens at the limit of a laser pointer's reach? | The '2 mile reach' is very arbitrary. I would imagine they define 'reach' as the largest distance without appreciable divergence of the beam. Beyond 2 miles the photons will still continue their journey at the same angles they left the pointer at.
I guess there will be a small amount of scattering and absorption by the atmosphere, but the largest contributor to drop in intensity will be the increase in the spot size due to the divergence of the beam. | [
"A Class 2 laser is considered to be safe because the blink reflex (glare aversion response to bright lights) will limit the exposure to no more than 0.25 seconds. It only applies to visible-light lasers (400–700 nm). Class-2 lasers are limited to 1 mW continuous wave, or more if the emission time is less than 0.25... |
how come d-day came as a surprise to the nazis? | Deception on a scale never before seen. Double agents. False radio transmissions. Fake armies. And even then, the Germans still knew an invasion was coming. But they were greatly misled as to when it would be, where it would be, and how many troops would be a part of it.
[Operation Bodyguard](_URL_0_) is the term for the operation that protected the truth of the Overlord landings until the final hour. It was, in fact, so effective that even *after the Normandy landings were underway*, Hitler delayed sending reinforcements - convinced that a second attack wave would be heading for the Pas de Calais region in northern France. | [
"Planning for the operation began in 1943. In the months leading up to the invasion, the Allies conducted a substantial military deception, codenamed Operation Bodyguard, to mislead the Germans as to the date and location of the main Allied landings. The weather on D-Day was far from ideal, and the operation had to... |
When and why did karate become a popular thing to teach children in the west? | I hope this is OK, I'm not a professional historian, but I was a karate-ka for about 20 years. And part of that was reading. So I hope I can provide an in depth answer that satisfies requirements. A lot of my reading comes from Randall Hassell's "Shotokan Karate: Its History and Evolution" and Gichin Funakoshi's "Karate-do Nyumon," and his "Karate-do Kyohan," as well as what I can recall from his autobiography "My Way of Life." I don't have the latter in front of me, so it will rely on memory a bit, sorry.
Now, this is told from the perspective a Shotokan Karate, which I understand to be the origin of the name. The beginnings were in Japan, in the Ryukyu islands, specifically Okinawa. The stories of Funakoshi learning Karate from Itosu and Azato, who are part of the history of a fighting style without traditional weapons because of the banning of weapons during the Meijii Restoration...I'm not competent to assess. Hassell says that there are Chinese roots as well for this style.
In 1924 Funakoshi was asked to teach a small group of Japanese university students (in addition to the private lessons he had been teaching prior. College clubs began coming together around this time. this also led to some splintering of Shotokan, but apparently without rancor.
Masatoshi Nakayama described training with Funakoshi as involving Kata (forms), followed by *Makiwara* practice (a board wrapped in rice rope and setup to practice striking). Hassell quotes him saying "When he [Funakoshi] selected a kata for us to practice, we would repeat it 50 or 6t0 times, and this was always followed by intense practice on the makiwara. We would punch the makiwara until our knuckles were bloody....the training was so grueling that of the 60 or so freshmen who enrolled with me in 1932, only six or seven of us made it through the first six months of training." He notes the around this time Funakoshi began teaching *gohon kumite*, a type of ritualized sparring practice drawn from kata. This evolved into *kihon-ippon kumite* and then into the free sparring techniques over a period of five years. These ideas are through out *Kyohan*.
And here is the key crossover moment:
> in 1953, the U.S. government prevailed upon Funakoshi to demonstrate karate for members of the Strategic Air Command (SAC) at several Far Eastern bases.[From later in the Hassell's book, I think this means Eastern US, I'm not positive on this.] At the age of 83 , this remarkable man boarded a U.S. government plane and, accompanied by Masatoshi Nakayama of Takushoku University, Toshio Kamata of Waseda University, and Isao Obata of Keio University, toured many U.S. air bases and demonstrated karate for thousands of members of SAC.
If we fast-forward past Funakoshi's death in 1957, we see the development of the Nihon Karate Kyokai (Japanese Karate Association, JKA) as a group that saw themselves as the overseers of Karate in Japan. The JKA began a somewhat divisive process of creating sport Karate. Nakayama talks about the dangers inherent in this creation, saying "My greatest concern at that time was to ensure that karate, if given a sporting aspect, would not lose it's essence as an art." It is around this time (mid 1950's) that the JKA develops it's Instructor Training Program (which, I'm relatively sure continues today, some friends of mine have gone through it in the past few years).
Back to the demonstration at air bases. According to Hassell, the "American interest was do great that many airmen began seeking instruction, and soon Karate and Judo clubs were established on the bases." Nakayama, apparently a big cheese in these demonstrations, begins to see difficulties in education Americans, in large part due to the huge difference in cultures (if you're interested in this, I can't recommend "Chrysanthemum and the Sword" enough.) The question of "Why?" Hassell notes as a new one for Nakayama.
The first official JKA instructor in the US was Teruyuki Okazaki who started in Philadelphia in 1961. I'm lucky enough to know a few people who have trained with him and say that he was a remarkable man. The JKA began starting dojo's in cities across the US at this time. Kansas City, New Orleans, Los Angeles, Denver, Hawaii, Chicago, Florida, New Jersey, Arizona. An organization started by Hidetaka Nishiyama, the All American Karate Federation, applied to the AAU in 1970, listing more than 20,000 members at the time. And I think there is your flood gate.
I hope I did justice to the material. Hassell's work is great, but I don't know if you can find it for a reasonable price (I think it is out of print. My copy, a second edition (ISBN 0-911921-09-5) is spiral bound. | [
"\"The Karate Kid\" is a semi-autobiographical story based on the life of its screenwriter, Robert Mark Kamen. At age 12, after the 1964 New York World's Fair, Kaman was beaten up by a gang of bullies. He thus began to study martial arts in order to defend himself. Kamen was unhappy with his first teacher who taugh... |
If oxygen can bond with 2 other atoms, how can ozone exist? | What you are thinking of is a very simplified picture of lewis-dot structure type bonding, where O has 2 unpaired electrons. Lewis structures are only really a simple tool to get a handle on more complicated concepts. Using the idea of resonance you can help explain ozone. See here: _URL_0_
But again, as stated before, here you have a central oxygen bonded to 2 other atoms (oxygen as well), so I'm not sure what exactly the question is asking. | [
"Three forms (or allotropes) of oxygen are involved in the ozone-oxygen cycle: oxygen atoms (O or atomic oxygen), oxygen gas ( or diatomic oxygen), and ozone gas ( or triatomic oxygen). Ozone is formed in the stratosphere when oxygen molecules photodissociate after absorbing ultraviolet photons. This converts a sin... |
Is it impossible for a planet the size of Jupiter to not be a gas planet? | Yes, a large enough planet will be a gas giant. All planets are made out of star-stuff which is mostly hydrogen (~90%) and helium (~9%) (the same stuff in gas giants). Rocky (terrestrial) planets will lose a large fraction of hydrogen and helium, as the light elements move faster at a given temperature and [have a larger probability to escape (overcome escape velocity)](_URL_0_). Thus hydrogen and helium have largely escaped the Earth's atmosphere, but on Jupiter they haven't largely escaped as its much more massive (and hence the escape velocity sqrt(2GM/r) is much easier to overcome). The rocky part of the planet on a gas giant tends to fall inwards more through [differentiation](_URL_1_) leaving only the gas part on the outer layers.
The boundary between the two is around 2 earth radii (~8 times the mass of the earth). E.g., shouldn't have gas giants below; or terrestrial planets above -- though it isn't a sharp transition (near the transition the atmosphere will keep more helium/hydrogen, but not as much as a gas giant). | [
"Given the planet's high mass, it is likely that 47 Ursae Majoris b is a gas giant with no solid surface. Because the planet has only been detected indirectly, properties such as its radius, composition, and temperature are unknown. Due to its mass it is likely to have a surface gravity 6–8 times that of Earth. Ass... |
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