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how does humidifier work? | So unlike boiling water where you have to heat the water to make it vaporize, humidifiers work differently.
What happens is there is an item inside the humidifier called a wick. The wick is almost like a sponge the just soaks up water. When you turn the humidifier on it sucks in air and blows it through the wick. Small warm particles of water are grabbed by the moving error and are sent through the air. | [
"A humidifier is a device, primarily an electrical appliance that increases humidity (moisture) in a single room or an entire building. In the home, point-of-use humidifiers are commonly used to humidify a single room, while whole-house or furnace humidifiers, which connect to a home's HVAC system, provide humidity... |
Why is it, whenever I look at snow for a lengthy period of time, my vision turns red? | what you're seeing is probably an [adaptation aftereffect] (_URL_0_) to bluish sky light reflected by all the white reflecting surfaces that are covering everything (the snow). over time, the retina (and the brain) acts to normalize stimulus distributions, so that if some stimulus is regularly over-represented it is relatively suppressed, and if some stimulus is regularly under-represented it is relatively enhanced.
the distribution of light wavelengths in the white light from a blue sky is strongly tilted towards short wavelengths (which is why the sky looks blue) - if you spend a lot of time looking at this light, your neural mechanisms which process short-wavelength light will decrease their sensitivity, while neural mechanisms processing longer wavelengths will have their sensitivity increased.
so, being adapted to white light with a 'cold' [color temperature] (_URL_2_) (i.e. stronger towards short wavelengths), when you get into an environment with a warmer color temperature (like white light from a lamp), you'll get an exaggerated response to the longer wavelengths and a suppressed response to the short wavelengths.
since what you normally perceive in response to longer wavelengths are redder colors, this means that everything you see will appear reddened - until you re-adapt to the local color temperature, which happens very quickly.
more generally, what you're talking about is a phenomenon called [color constancy] (_URL_1_), where the visual system is constantly trying to 'divide out' the wavelength distribution of the local illuminant. i could give some references if you want to go deeper into that... | [
"Scheerer's phenomenon can be distinguished from visual snow because it appears only when looking into bright light, whereas visual snow is constantly present in all light conditions including the dark.\n",
"Although ice by itself is clear, snow usually appears white in color due to diffuse reflection of the whol... |
How much radiation do I get by opening the microwave door before it has finished? | It's hard to tell- Must likely the Magnetron will cut off quickly as you open the door.
But you certainly don't get any radiation of the kind people usually think about when referring to radiation. I.e. there is a huge difference between microwaves and the radiation, such as gamma rays, which is associated with nuclear processes. Microwaves are less energetic than visible light, whereas gamma rays are much more energetic. Thus, microwaves cannot ionize molecules, such as your DNA, and will therefore not cause cancer. The radiation in a Microwave oven is ~~tuned to the rotational frequency of water~~, so all it does is make the water molecules wiggle around, which creates heat.
/Zaim
Ph.d. student in quantum optics and nanophotonics.
Edit: The microwave frequency is not tuned to the rotational resonance of the water molecule as I implied above. If it was, all the radiation would be absorbed on the surface of the food. Instead it is tuned away from the resonance, so that it can penetrate into the middle of the item. | [
"The first is that the device immediately ceases production of the microwave radiation when the door is opened, which checks that the safety interlock systems are functional; and the second is that any leakage when operating is less than 5 mWcm which indicates that the door and casing are not distorted and any seal... |
Are Palestinians to a significant extent Arabized Jews? | Apologies, but we have had to remove your submission. We ask that questions in this subreddit be limited to those asking about history, or for historical answers. This is not a judgement of your question, but to receive the answer you are looking for, it would be better suited to /r/AskScience.
If you are interested in an historical answer, however, you are welcome to rework your question to fit the theme of this subreddit and resubmit it. | [
"Israeli Arabs constitute roughly 20% of the population in Israel. Many Israeli-Arab groups claim continued institutional and social discrimination against them in Israel. Because they are not Jews and many identify ethnically with Palestinians their identity often clashes with their citizenship in the Jewish state... |
If instantaneous communication was possible between a person on Earth and a person accelerating near the speed of light in outer space (supposing this, too, was possible), what would the conversation look like since "time" is going much faster for the Earthbound person than it is for the traveler? | This question is invalid as stated - the moment you "pretend" instantaneous communication is possible, you throw relativity out the window, and thus can;t say anything about how perception of time differs between the two reference frames.
You cant have your cake and eat it too - the same theory that tells us how to relate time between the two reference frames tells us FTL communication is impossible. | [
"BULLET::::- Point-to-point teleportation at the speed of light is possible with transfer booths (on Earth) and stepping disks (on the Puppeteer homeworld); on Earth, people's sense of place and global position has been lost due to instantaneous travel; cities and cultures have blended together.\n",
"BULLET::::- ... |
What common historical misconception do you find most irritating? | One of my biggest peeves, which will set me spinning off in a rage even at its mention, is the anti-Stratfordian conspiracy theory. This so-called "theory" is that Shakespeare either didn't exist, or was merely a front for some other "real" author.
This load of tripe was conceived in the 19th century by a bunch of classists and intellectual elitists who insisted that works of quality like Shakespeare's couldn't possibly be produced by somebody from the lower classes and of humble background, so therefore they clearly must have been written by a noble or an aristocratic person who was simply too modest to take credit.
It demonstrates complete ignorance of how theatres, playwrights, and actors operated in the period, makes up absurd tests of validity that would be failed by 99% of all people ever born, and is rooted firmly in the belief that there was somehow a nationwide conspiracy by all levels of society up to and including the royal court to invent, adore, criticize, eulogize, pay, and grant arms to, a fake author that there is not one ounce of evidence to support. | [
"The history of misinformation, along with that of disinformation and propaganda, is tied up with the history of mass communication itself. Early examples cited in a 2017 article by Robert Darnton are the insults and smears spread among political rivals in Imperial and Renaissance Italy in the form of \"pasquinades... |
Why do humans react the way they to music/beats? And why don't other mammals react the same way? | Parrots dance! Just type "parrot dancing" in youtube and you will have a treasure trove of delightful dancing birds :)
My favorite:
_URL_0_ | [
"Listening to music and general audio is commonly not a task directed activity. People enjoy music for various poorly understood reasons, which are commonly referred to the emotional effect of music due to creation of expectations and their realization or violation. Animals attend to signs of danger in sounds, whic... |
Can you recommend me a couple of books on the history of the Holy Roman Empire, Reformation and the Thirty years war? | On the Reformation: Diarmaid MacCulloch, 'Reformation: Europe's house divided, 1490-1700', London 2004.
EDIT: This is an excellent read, very informative and entertaining
On the Thirty years war (and naturally with some information on the HRE): R.G. Asch, 'The thirty years war: The Holy Roman Empire and Europe, 1618-1648', New York 1997.
Sadly I don't know any good books which only cover the HRE. | [
"BULLET::::- Philip Schaff. «History of the Christian Church» / Volume VIII / HISTORY OF THE REFORMATION. 1517 – 1648./ THIRD BOOK. THE REFORMATION IN FRENCH SWITZERLAND, OR THE CALVINISTIC MOVEMENT. / CHAPTER XV. THEOLOGICAL CONTROVERSIES. / § 122. Against the Worship of Relics. 1543.\n",
"\"Book I: The Holy Rom... |
Why is 0-14 used for the pH scale? What are the highest and lowest pH substances both in existence and theoretically possible? | The pH scale is related to the molar concentration of hydrogen ions. Normal water has a H+ concentration = 10\^-7, therefor the pH is 7. Technically, pH is the -log10 \[ hydrogen ion activity\]. The scale goes beyond 0 - 14, but only uncommon substances are outside this range. Battery acid is pH = 0, meaning the H+ activity is 100%. Pure liquid lye drain cleaner is pH = 14, so the H+ activity is 10\^-14 (very low), and the OH- activity is very high.
Hot saturated solution of sodium hydroxide can reach pH = 16. Very concentrated HCl solutions have pH = -1.1, and some waters from the Richmond Mine in California are reported at pH = -3.6. | [
"The pH scale is logarithmic and approximates the negative of the base 10 logarithm of the molar concentration (measured in units of moles per liter) of hydrogen ions in a solution. More precisely it is the negative of the base 10 logarithm of the activity of the hydrogen ion. At 25 °C, solutions with a pH less tha... |
This morning as I stirred my coffee it happened to be on a kitchen scale. I noticed that the weight of the spoon registered on the scale, even when I was holding it. Why? | The coffee provides a buoyant force to the spoon, pushing it up, making it lighter in your hand. The counter to this force is added weight on the scale. | [
"From 1743, the Celsius scale is based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure. Prior to 1743, the scale was also based on the boiling and melting points of water, but the values were reversed (i.e. the boiling point was at 0 degrees and the melting point ... |
How do donated organs remain viable without blood flow? | Organs can usually last a few hours at very low temperatures (but not freezing). This is normally sufficient to get from the donor to the recipient.
Same goes with the heart muscle during a myocardium infarction. Serious damage to the heart muscle doesn't happen immediately but is progressive the longer the affected area of the heart is without oxygen. | [
"In living donors, the donor remains alive and donates a renewable tissue, cell, or fluid (e.g., blood, skin), or donates an organ or part of an organ in which the remaining organ can regenerate or take on the workload of the rest of the organ (primarily single kidney donation, partial donation of liver, lung lobe,... |
Why are all the planets on the ecliptic plane? Why are there other celestial objects orbiting the sun that are not on the ecliptic plane? | [This is a very frequently asked question](_URL_0_). | [
"Most large objects in orbit around the Sun lie near the plane of Earth's orbit, known as the ecliptic. The planets are very close to the ecliptic, whereas comets and Kuiper belt objects are frequently at significantly greater angles to it. All the planets, and most other objects, orbit the Sun in the same directio... |
despite intense competition and very small profit margins in the mobile phone market, how do companies like xiaomi manage to provide significantly better hardware specs than relatively larger & older companies like samsung and sony? | A few reasons.
Xiaomi's business model is like that of Kuerig, or Xerox, or HP printers. They will practically *give* you the device, because that is not the actual product. What they sell is software, the device is just a means of getting it to you.Printers are cheap, but you have to keep buying toner. Kuerig machine are a marvel of engineering, but the coffee is what keeps you coming back to the trough.
They sell through online outlets, instead of brick and mortar stores.
Xiaomi is Chinese, they have an enormous indigenous consumer base, favorable tax liabilities to serve that base, and slave labor to produce for it. These reasons are why trade agreements with the Chinese are a joke, and probably immoral, not many other countries can just force people to do shit. All the while dumping incalculable waste, without any first world restrictions. Result: cheap ass phone, with quality components for the consumer.
| [
"Several sources, including \"The Economist\", have identified Amazon, Apple, Google and Microsoft as the four platform cloud companies which will be the key competitors in the post-PC era of mobile computing. Tech companies with a heavy dependency on PC sales such as Hewlett-Packard and Dell have seen decreased pr... |
How did anti-miscegenation laws in the USA deal with mixed-race couples where neither partner was white? | The usual disclaimer is along these lines: These listings just indicate previous articles that may be applicable. This is not to discourage new questions.
A search for
> jim crow asian
(merely as likely terms to have been in an article) includes a reply, [When interracial marriages were illegal in some states in the U.S., what did biracial people do? Could they simply not marry anyone in those states?](_URL_0_). They say they "assume" it was true in other states but provides no data, but they correctly note that Loving v. Virginia's Supreme Court decision says "While Virginia prohibits whites from marrying any nonwhite (subject to the exception for the descendants of Pocahontas), Negroes, Orientals, and any other racial class may intermarry without statutory interference." ([here](_URL_2_), in note 11).
I found a few more general posts, but they don't talk about marriage in particular, so I don't know whether they apply to marriage too.
[How were non-black minorities treated in the Jim Crow South](_URL_1_). /u/Dubstripsquads's reply says that different categories were variously treated as white or as non-white, depending on location or time.
There was also [What was Jim Crow/segregation era America like for non-black minorities?](_URL_5_) It cites and approves of the book [What Comes Naturally: Miscegenation Law and the Making of Race in America](_URL_4_).
[What was the status of Jews and Asians in America during racial segregation?](_URL_3_) is older and doesn't cite sources.
| [
"Anti-miscegenation laws or miscegenation laws enforced racial segregation through marriage and intimate relationships by criminalizing interracial marriage. Certain communities also prohibit having sexual intercourse with a person of another race. These laws have since been changed in all U.S. states - interracial... |
why do vacuum insulated containers insulate cold beverages longer than hot beverages? | They don't. It's a difference in your perception of what constitutes "hot" and "cold", and the way thermal transfer works.
Room temperature is ~70F; a hot beverage might be ~170F. A 100F difference. A cold beverage isn't going to be any colder than ~32F, about a 40F difference.
So you need to heat your beverage up a lot for you to think of it as truly hot...much more so than making a beverage cold.
Then there's heat transfer. Heat transfer happens the fastest when the temperature difference is the greatest. So your "hot" beverage initially loses heat faster than your "cold" beverage gains it.
So there are two factors working against the hot beverage. It cools faster due to the greater temperature difference, and you don't think of it as "hot" when it cools down just a bit.
If you were to take 2 beverages and cool one 20 degrees below room temperature and heat another 20 degrees above room temperature, you'd find that they both approach room temp at the same rate.
EDIT: Note that to do this correctly, I should have represented all temperatures in Kelvin. The conclusions are still correct, but the numbers are not quite right as I wrote it.
| [
"A vacuum flask (also known as a Dewar flask, Dewar bottle or thermos) is an insulating storage vessel that greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the ot... |
What caused the guitar, an instrument not found in a typical orchestra, to become the de-facto popular music instrument? | Hi, not discouraging further contributions here, but do check out these earlier answers
* /u/hillsonghoods on the hugely entertaining [AskHistorians Podcast 067 - 20th Century Popular Music and the Rise of Guitar Groups](_URL_1_); as well as in [How did the default set of instruments for modern bands come to be 2 guitars, bass, keyboards, drums, and vocals? Why is it so rare to hear instruments other than these in popular music since the 1950s?](_URL_2_) and [When did the modern concept of the 'band' begin? I.e. The four piece guitar, bass, drums, singer set up. Was it popularized by a single group?](_URL_0_)
* /u/Kai_Daigoji in [Why is the guitar the standard instrument for modern music?](_URL_3_) | [
"From the late 18th century the guitar achieved considerable general popularity though, as Ruggero Chiesa stated, subsequent scholars have largely ignored its place in classical music. It was the era of guitarist-composers such as Fernando Sor, Ferdinando Carulli, Mauro Giuliani and Matteo Carcassi. In addition sev... |
Why is it that when I eat from an aluminum container with a steel fork I get a similar taste sensation as when I put a battery on my tongue? Is there a reaction going on? | Potentially yes, assuming you cook with salt. When two dissimilar metals are connected together by an electrolyte, they form a galvanic cell.
See: _URL_0_
These were the first types of batteries.
It can also lead to corrosion of metals, if they are kept in contact for too long. This is a corrosion mechanism in the molten salt reactor. | [
"Neurotoxic behavior of aluminum is known to occur upon entry into the circulatory system, where it can migrate to the brain and inhibit some of the crucial functions of the blood brain barrier (BBB). A loss of function in the BBB can produce significant damage to the neurons in the CNS, as the barrier protecting t... |
why do some antennas such as the kind for tv have such a rail-like design? | The series of parallel elements are called directors, and they, in effect, focus the signal.
A simple wire, sticking up, will have a sensitivity pattern which is circular with is centre around the wire, but this isn't much use for receiving faint signals and shutting out interfering signals. The [Yagi-Uda antenna](_URL_0_) uses the row of directors to stretch the sensitivity in the direction of the directors - that is, along the line of the "rail" of the antenna. This allows it to collect faint signals from (nearly) a single direction.
The gains can be quite startling, but adding extra elements has increasingly little effect, so you don't often see ridiculously long versions. | [
"Since directional antennas must be pointed at the transmitting antenna, this is a problem when the television stations to be received are located in different directions. In this case two or more directional rooftop antennas each pointed at a different transmitter are often mounted on the same mast and connected t... |
Are humans evolving to appear more physically attractive? | I have read that some scientists believe that beauty is an indicator of good health, and thus was probably important to mate selection, and yes, would thus consequently have lead to favoring that genetic trait.
However, you asked the question in the present tense, and the current reality is probably reversed. The best looking, healthiest, smartest, most well off individuals in our society are today often single or have just one or two children, because they are too busy living their awesome lives to have more. On the other hand, the bored, poor, poorly educated, and ... less than gifted in the beauty sense ... often have many children. Please don't shoot me, I'm just the messenger. | [
"Physical attractiveness can have a significant effect on how people are judged in terms of employment or social opportunities, friendship, sexual behavior, and marriage. In many cases, humans attribute positive characteristics, such as intelligence and honesty, to attractive people without consciously realizing it... |
how come when i put the tip of an aux cable against my skin when its already plugged into another device, how come it appears to make a signal? | Going to take a rough while I am on the Thunder dome at work
You body will act like it is connected to the cable and because you body creates thousands of millions of small electromagnetic pulses throughout your nerves and what not, this then creates the "noise" signal
Like I said rough guess while I am pooping at work. | [
"The device consists of a molded plastic housing that attaches to the end of an electrical conduit that carries the underground cables up the utility pole to the crossarm. Multiple bushing insulators project from the plastic body, each ending at an electrical terminal. Each overhead wire is connected to a bushing t... |
how do you have money to spend when "all your money is in stocks"? | "Heavily Invested" and "All In" are not the same thing. If Bill Gates invests 90% of his money in stocks he is still wealthier than you and I by a large margin.
Plus, stocks are pretty liquid assets. Its not hard to sell off some shares if you need some cash. | [
"When money or goods that have been kept are brought back into the economy, for example when people invest or spend money rather than save it. Or it can also be defined as the activity of investing money or selling gold, silver, etc. after a period during which investors have saved them.\n",
"Money also functions... |
Were Normans Vikings? | Most people living in Normandy were not descended from Vikings. Following Rollo's appointment as Duke there was no mass-migration of Scandinavians. It was primarily the elite that were descendants of the original Viking invaders, and they very often intermarried with French nobility to form alliances and entrench their power.
Arguably however, these elite retained some aspects of Scandinavian culture, and their ventures abroad can be seen in the wider context of later Viking activity. Sarah Davis-Secord (*Sicily and the Medieval Mediterranean*) refers to a "lure of profit and adventure" which drove the Normans to Sicily for instance. Like the Vikings, they were prominent as seafarers and mercenaries. Graham Loud in *The Age of Robert Guiscard* argues that the Normans were present in Italy as mercenaries before the events described in either the Salerno or Gargano traditional accounts of the Norman arrival. From minor military positions in the armies of Salerno, the Normans rose to power, possibly with the help of Papal intervention, and established the Kingdom of Sicily. This mirrors contemporary Scandinavian activities - The Byzantine Varangian Guard for example established for themselves a strong position within Byzantine society. Harald Hardrada served with them before becoming King of Norway. This "lure" could even be applied to Norman ventures in the British Isles, the most obvious example being the adventures of Richard de Clare (Strongbow) in Ireland. So it could be said that Norman warriors and elites continued some parts of Viking culture. | [
"The Normans were descended from Vikings who had settled in Normandy, and although they had adopted the French language, their heritage and self-image were essentially Viking. In this manner, the Vikings ultimately (if indirectly) finally conquered and kept England after all. \n",
"The Normans (Norman: \"Normaund... |
how do they restore old videos to 60 fps? | I would say that either they had an original of the record in 60 FPS, which was not uploaded back then or recreated the "missing" frames by "averaging" of the frames before/after of some sort. | [
"Originally BD-ROMs stored video up to 1920×1080 pixel resolution at up to 60 (59.94) fields per second. Currently with UHD BD-ROM videos can be stored at a maximum of 3840×2160 pixel resolution at up to 60 (59.94) frames per second, progressively scanned. While most current Blu-ray players and recorders can read a... |
How far can electricity travel through our electrical grid? | For long distance transport, power is converted to a very high voltage and transported in high-diameter cables, usually Al for cost.
A very naive calculation (300kV_RMS and 750mm^2 cross-section aluminum wire @ room temperature) assuming all the power of the Hoover dam is used (that's 2080MW) says that the maximum absolute length of wire so that all the power is used for ohmic heating is about 7200 km. So 3600 km because you need a return path, and then a bit shorter than that if you want some power left to do something useful.
In actuality though I think the power grid is so complex (many transformers and tie-ins to other power stations) that if only one power plant was working, the power would dissipate in the spiderweb of connections, plus the computerized control and feedback systems that ajust load for certain grid sections would immediately fail. | [
"As originally built, the line was 153.4 miles long, crossing the Continental Divide at Hagerman Pass (at altitude 12,055 feet), Fremont Pass (at altitude 11,346 feet) and Argentine Pass (at altitude 13,532 feet). For many years, this was the highest electric power transmission line in the world. The three-phase li... |
if air is a better insulator than water, why do clouds trap heat? | Heat is transferred in three ways
1. Radiation - This is IR and other energy which is emitted from something warm
2. Conduction - This is energy transferred between two objects that are physically touching
3. Convection - This is the movement of energy through currents like hot air rising and cold air sinking or running a fan to even out the temperature
When you talk about air being a better insulator than water you're talking about conduction of heat. Water is significantly denser so particles bump into each other and pass energy around much quicker than in air. We generally design insulation to have little air pockets so there isn't enough air to have significant heat transfer from convection.
Clouds trap heat by blocking radiation transfer. The warm Earth emits IR which on a clear day will continue out into space, but on an overcast day will bounce off the clouds and come back to Earth or be absorbed and warm the cloud. Since there is no mass to conduct heat to in space, the only way for the Earth to get rid of energy is to radiate it out into space so blocking that path results in the Earth staying warm. | [
"A vapor barrier on the warm side of the envelope must be combined with a venting path on the cold side of the insulation. This is because no vapor barrier is perfect, and because water may get into the structure, typically from rain. In general, the better the vapor barrier and the drier the conditions, the less v... |
how can malt-o-meal blatantly rip off every brand-name cereal while apple and samsung have been in legal issues since the beginning of time? | You can't copyright a recipe for food and usually can't patent a food product. The specific form in which a recipe is presented can be copyrighted (the words and formatting), but as long as someone changes up the words they can use the same ingredients, measurements, and steps. Similarly, you can protect branding and food packaging, but not a food product. If someone figures out how to make a Twinkie and sells it with different packaging and branding, they're allowed to.
Malt-O-Meal can get away with it because their packaging and branding is different. For example, they don't use Lucky the Leprechaun with their Marshmallow Mateys cereal (similar to Lucky Charms); they use a kangaroo instead. Also, I don't even think the recipe is exactly the same because their cereals definitely taste a little different. Th
Edit: You can patent some food products, but they have to be non-obvious and novel. Most food products are obvious variations on old recipes (like with cereal). Examples of food products that have been patented include egg yolk substitutes and sealed crustless sandwiches.
Edit 2: You can all go make your own sealed crustless sandwiches. Turns out the product was patented by Smuckers in 1999, but the patent was reexamined and rejected by the US Patent and Trademark Office in 2003. Smuckers' application to patent the process for making the sandwiches was also rejected.
Edit 3: The process for making "marbits" (the marshmallows in Lucky Charms) is patented: _URL_0_. I don't know what process Malt-O-Meal uses, but as long as it's different they should be fine. The main point that you can't patent a recipe is still true for cereals in general.
| [
"Kellogg Co. v. National Biscuit Co., 305 U.S. 111 (1938), is a United States Supreme Court case in which the Court ruled that the Kellogg Company was not violating any trademark or unfair competition laws when it manufactured its own Shredded Wheat breakfast cereal, which had originally been invented by the Nation... |
[Physics] Considering that the photons would never be absorbed by the 100% reflective mirror, what would happen inside? It's in the realm of a thought experiment since you'll never be able to measure the result. | I think that he is asking about the inside of a perfectly reflective box. Yes it would bounce around forever, here's why:
The photon is an electromagnetic wave in a vaccum, and is classically defined as a pair of coupled wave equations: _URL_0_.
Imagine a mirror in 1-D propagation. A perfect mirror, (100% reflection) can be mathematically modelled as a specific boundary condition at the physical boundary, (lets say, X = 0 and X = L), which governs the energy transfer and reflection from the surface. In this case, (1D), the wave equation is v^2 f_XX(x, t) = f_TT(x,t). With an initial condition of f(x,0) = initial_trapped_wave(x) and f_t(x,0)=0, (some initial waveform, and no first order temporal derivative). The boundary condition is such that there is no restoring force acting on the wave front at the boundaries, so something like f_tt(0,t)=0, f_tt(L,t)=0.
Then, without loss of generality, expand this to 3-D and limit wave propagation to some box in R^3. It will just keep reflecting. | [
"Mirror matter could have been diluted to unobservably low densities during the inflation epoch. Sheldon Glashow has shown that if at some high energy scale particles exist which interact strongly with both ordinary and mirror particles, radiative corrections will lead to a mixing between photons and mirror photons... |
What is the effect of strength training on lifespan? | I think you need to be more specific. Anything that uses your muscles will build strength. Push-ups, pull-ups, and standing squats, all use your own body weight to strengthen muscles. If you use these exercises as aerobic activity you will get cardio health benefits.
If you are talking about anaerobic weight lifting to add muscle, I don't know of any specific health benefits from doing this alone. | [
"Traditionally, strength training (the performance of exercises with resistance or added weight) was not deemed appropriate for endurance athletes due to potential interference in the adaptive response to the endurance elements of an athlete's training plan. There were also misconceptions regarding the addition of ... |
how are hand sanitizer companies able to claim their product is better or more effective than their competitors when they all kill 99.9% of all germs? | No government oversight or enforcement of false product claims. Assume all copy on products is a lie. | [
"The main difference between a sanitizer and a disinfectant is that at a specific use dilution, the disinfectant must have a higher kill capability for pathogenic bacteria than that of a sanitizer. If these micro-organisms are not destroyed, the bottled water being produced may be contaminated. \n",
"On April 30,... |
how do martial artists break huge stacks of bricks without their hand passing through every brick? | Dominos. The force is transfered from the top brick down by the breaking bricks themselves. | [
"Aspiring boxers undergo years of apprenticeship, toughening their fists against stone and other hard surfaces, until they are able to break coconuts and rocks with their bare hands. Any part of the body may be targeted, except the groin, but the prime targets are the head and chest. Techniques incorporate punches,... |
Why do you feel a jerk when a car comes to a complete stop? | [Jerk](_URL_0_) is actually a technical term, and part of the answer.
I'm sure you're familiar with that feeling of being pushed forward when you're just braking. That's a result of inertia but it feels as if there was some force pushing you forward a bit, and we can even think of it that way. The same happens to the car, but the car has suspension on each tire. The front suspension springs contract a bit as a result. While you're braking, there's this fictitious force pushing the front suspension down but the springs are also pushing up, and they stay contracted at some length where these two forces balance exactly.
The actual force of friction doing the braking remains pretty much constant all the way, which means that the fictitious force pushing down the suspension also remains constant and the amount of contraction in springs also remains constant. Then you come to a complete stop and suddenly the force of friction is gone, and with it the fictitious force pushing down on the front suspension. The springs however are still contracted but now there is no force keeping them that way, so they must extend to their natural length. This makes the chassis of the car bounce back a bit. Same as with normal braking it felt like there was some force pushing you forward, with the chassis bouncing back, you again feel as if something's pushing you forward although there actually is no such force, it's just the inertia.
If you slowly release the brakes just as the car is coming to a halt, then the force of friction gradually goes down which means that the springs gradually extend and there is no bounce (or at least not as big) when you finally stop.
Jerk is to acceleration what acceleration is to speed, it's the rate of change of acceleration. With slowly releasing the brakes, the jerk right at the end is small. With constant braking that results in the springs and chassis bouncing, you have a very high jerk right at the end when acceleration goes from some value to zero in an instant. | [
"Since forces, changing at a suitable rate in time (that is, \"suitable\" jerk) are the cause of vibrations, and vibrations significantly impair the quality of transportation, there is good reason to simply \"minimize\" jerk in transportation vehicles.\n",
"BULLET::::- High-powered sports cars offer the feeling o... |
what are magnet links? | They tell your PC to open up an application, then send that application some data.
Other uses include: Starting a skype call to a number, Opening up mumble and connecting it to a server, opening up steam to download a game, and more.
They are very useful, and need more use! | [
"Although magnet links can be used in a number of contexts, they are particularly useful in peer-to-peer file sharing networks because they allow resources to be referred to without the need for a continuously available host, and can be generated by anyone who already has the file, without the need for a central au... |
Can any bacteria survive the boiling point of water? | Yes, see [wikipedia](_URL_1_) for a list of examples, such as [this one](_URL_0_) which can survive and reproduce above boiling temperature. | [
"However, the observations proved that it is actually possible for life to exist at high temperatures and that some bacteria even prefer temperatures higher than the boiling point of water. Dozens of such bacteria are known.\n",
"BULLET::::1. Boiling: Bringing water to its boiling point (about 100 °C or 212 F at ... |
Why were Roman replicas of the bronze Greek statues made of marble? | They often did, but marble is cheaper than bronze, so *most* replicas were marble. The Roman use of Greek statues was very often a change in context from public to private--many of the most famous statues were originally set up in either official or religious spaces, while the Romans would often place these in private contexts. So a wealthy Roman would have a copy of a famous temple statue commissioned for his garden--or, increasingly likely, would simply buy a premade statue. Marble is a much cheaper material than bronze, so these would generally be marble.
Another factor deals with material survival. Almost every classical bronze statue you see was recovered from a shipwreck, because bronze statues could be melted down and recast, either into other works of art (Bernini's altar in St. Peter's is a rather famous example of this) or, more commonly, cannons. Therefore, almost all of the classical bronze that survives is that which was taken out of circulation, so to speak. | [
"Many of the Greek statues well known from Roman marble copies were originally temple cult images, which in some cases, such as the Apollo Barberini, can be credibly identified. A very few actual originals survive, for example, the bronze Piraeus Athena ( high, including a helmet). The image stood on a base, from t... |
does fractional reserve banking cause all money to be created in the form of debt? | Fractional Reserve banking is not started from scratch in any of the economies. They simply plug it in to the system. So there is some extent of money already present in the system for the Fractional reserve banking to work.
> where is the money used to pay interest over and above the principal coming from?
The system will collapse if everyone will pay off debt. There will be no money left. That is why central banks will print crazy amount of money to keep the cash flow going. | [
"Fractional reserve banking has resulted in a transfer of wealth from the holders of currency to investors. Under fractional reserve banking the money supply is allowed to be increased whenever new interest-bearing loans are issued and is often constrained by a reserve ratio, which mandates that banks hold a portio... |
why does fast air feel cold, if temperature is a measure of kinetic energy, even when i'm not sweaty? | Because the air temperature is lower than you body temperature when it blows past your skin it's still taking heat away from the body.
Causing the air to feel cool. | [
"At high speeds through the air, the object's kinetic energy is converted to heat through compression and friction. At lower speed, the object will lose heat to the air through which it is passing, if the air is cooler. The combined temperature effect of heat from the air and from passage through it is called the s... |
What causes light to slow when it travels through a medium? | Dielectric materials are full of electric charges (positive nuclei and negative electrons). The charges aren't free to move around, but they do get tugged around a bit by electric fields: the electrons and nuclei are pulled in opposite directions in an electric field, and so a tiny electric dipole is formed. This is called polarization.
When light---consisting of oscillating electric and magnetic fields, but the electric part is more important here---hits a polarizable material, it creates tiny oscillating electric dipoles. Oscillating electric dipoles produce light of their own at the same frequency. However, the produced light is not exactly in phase with the incoming light. The remarkable thing---and it is quite remarkable that it works out this way---is that the combination of the incoming and all of the produced light is exactly the same as a single light wave with a slower velocity (and potentially a different direction, in the case of refraction). This is not an obvious fact and requires some study of Maxwell's equations to fully appreciate.
There is a common mis-explanation that the slowing is due to some sort of time delay between absorption and re-emission of photons. It's not *entirely* wrong but it does over-simply. The slowing of light is due to the collective effects of many atoms in the material, and there's no true absorption happening. Plus, you can get rather bizarre effects in special materials, including *speeding up* of light (in a peculiar way that doesn't violate special relativity---only the peaks of the wave move faster than c, not any energy or information). These things are harder to see within the absorption-emission picture but are quite compatible with the collective-dipole-wiggles picture. | [
"When light propagates through a material, it travels slower than the vacuum speed, . This is a change in the phase velocity of the light and is manifested in physical effects such as refraction. This reduction in speed is quantified by the ratio between and the phase velocity. This ratio is called the refractive i... |
why the martingale betting strategy doesn't work. | It does and it doesnt, in THEORY it does, as you explained, eventually your numbers come up and you will always be up your initial stake. you reset and start again.
The problem comes in that casinos predict people doing this, they have max bets, so say if the max bet is £40 (for ease), you start with £10, you lose, up it to £20, bet the £20 you lose and go to £40 and lose, then you are actually down £70 and you cant go up any further. So in theory it works, but in practice it doesnt. I hope this helps.
| [
"Originally, \"martingale\" referred to a class of betting strategies that was popular in 18th-century France. The simplest of these strategies was designed for a game in which the gambler wins their stake if a coin comes up heads and loses it if the coin comes up tails. The strategy had the gambler double their be... |
carbs, protein, fats - in which order are these used by the body and why? | Glucose is our staple energy source. If the body needs energy, glucose is broken down producing ATP and releasing CO2 and H20. If the body does not need energy, the glucose is built in to chains for easy storage in liver. These chain molecules are called glycogen. They are easily accessed and broken down to glucose whenever blood sugar levels decrease to provide the body with energy,
During starvation, when there is no energy provided by food, the body has to break down it's 3 main energy stores - liver glycogen, body fat and muscle. Your body begins by breaking down the liver glycogen. Next is body fat and and if desperate - muscles. In terms of weight and total calorific content this comes to, for an exemplar 70kg male; about 0.2kg liver glycogen = ~800kcal, about 15kg triacylglycarides (TAGs = major component of body fat)= ~135,000kcal and 6kg muscle = ~24,000kcal.
As you can see, body fat is the major energy store of the body. Fat cells exist partly to be used as an energy store. However, the body will break down glycogen first always as its simpler and more direct. Breaking down body fat (TAGs) for use as energy requires two more complex processes; 1) beta-oxidation of fatty acids to the natural precursor for a specific stage in the same natural metabolic pathway as glucose, and 2) gluconeogenesis, producing glucose from glycerol ( a non-carb source!).
Muscles are the last to be broken down, for obvious reasons - we need them. Muscle breakdown doesn't only affect things like leg and arm muscles, but also things like cardiac and diaphragm muscle, so it is really a last attempt for the body to survive by breaking these down. This would probably be around a couple weeks in to starvation and death would soon follow. | [
"Molecules of carbohydrates and fats consist of carbon, hydrogen, and oxygen atoms. Carbohydrates range from simple monosaccharides (glucose, fructose and galactose) to complex polysaccharides (starch). Fats are triglycerides, made of assorted fatty acid monomers bound to a glycerol backbone. Some fatty acids, but ... |
Was the failure of communism due to inherit flaws in the ideology or because the countries that adopted it were poorer and fewer than their capitalist counterparts? | You seem to have a bunch of different questions here. For the questions in the last paragraph you might consider /r/HistoryWhatIf . | [
"While having been a relatively unknown system due to the failure of authoritarianism within the First World during the Cold War, with the transition of authoritarian countries such as China and Russia to capitalist economic models, authoritarian capitalism has recently rose into prominence. While it was initially ... |
why did people in places like africa develop darker skin when black absorbs the most light compared to lighter colors? | Dark skin is caused by melanin. When the sun hits your skin it gets absorbed by melanin and not by your skin cells. This is a good thing because if your skin cells absorb the sun it can cause damage that can possibly lead to skin cancer. | [
"Historically, the cause of skin lightening goes back to colonialism, where individuals with lighter skin received greater privilege than those of darker tones. This built a racial hierarchy and color ranking within colonized African nations, leaving psychological effects on many of the darker skinned individuals.\... |
in electromagnetic waves, how are photons produced, how does the electric force and magnetic force interact and what factors effect the energy of a photon/wave? | A photon is a little packet of energy in the form of oscillating electric and magnetic fields. They fly around at the speed of light. When certain photons hit our eyes, they tell our brain that we're seeing something.
The energy of a photon depends on its frequency (or its wavelength). The lowest energy photons are radio waves, then microwaves, then infrared, then red light, then blue light, then ultraviolet, then x-ray, and finally gamma rays. Out of all of those, we con only see the small amount of light between infrared and ultraviolet. | [
"Classical waves transfer energy without transporting matter through the medium (material). For example, waves in a pond do not carry the water molecules from place to place; rather the wave's energy travels through the water, leaving the water molecules in place. Additionally, charged particles, such as electrons ... |
How expensive were candles in the 18th century? Could only the rich afford to light their homes after dark? Was it a major expense to host a party at night considering candles were made of beeswax or the wax extracted from sperm whales? | You are forgetting about [tallow](_URL_0_) candles, which have also been around for a long time. They are made from rendered animal fat. Candles would not have been very expensive, though the very poor would not have been able to afford them. | [
"By the late 19th century, Price's Candles, based in London, was the largest candle manufacturer in the world. Founded by William Wilson in 1830, the company pioneered the implementation of the technique of steam distillation, and was thus able to manufacture candles from a wide range of raw materials, including sk... |
Why are some of the heavier elements more common than the lighter ones in the universe? | Different elements, different methods of formation.
Some of the heavier atoms [like iron] are made in every star, but a few of the lighter ones are only formed in cosmic ray collisions [ lithium, beryllium, and boron ].
If you are interested in this, track down this book: ["The Magic Furnace" by Marcus Chown](_URL_0_)
It explains where all the various atoms came from, and how we figured it out. It is very clearly written. I got mine used through Amazon for just a couple of quid. | [
"The presence of heavier elements hails from stellar nucleosynthesis, the theory that the majority of elements heavier than hydrogen and helium in the Universe (\"metals\", hereafter) are formed in the cores of stars as they evolve. Over time, stellar winds and supernovae deposit the metals into the surrounding env... |
Are there any families from the Roman Republic period that survived into Late Antiquity? | There are plenty of claims, but there is no way for modern historians to confirm any of them. The Anicii only appear in 298, when Anicius Faustus became the consul and I don't think there's any indication that they publicised their Republican heritage - the late antique Anicii originally came from North Africa, whereas the Republican Anicii came from central Italy. Of course, the imperial Anicii could still be descended from the earlier family, but we cannot evaluate this hypothesis with the available evidence. The Anicii's claim to antiquity may have come from their marriage into the Acilii Glabriones, who did have what appears to be a long and distinguished ancestry. But even then this is only based on the fact that a certain Anicius Acilius Glabrio Faustus (consul in 438) was the son of Acilius Glabrio Sibidius, which has been interpreted by Alan Cameron as evidence that Sibidius had married a female member of the Anicii and added 'Anicius' to his son's name to 'advertise their union'. The Acilii Glabriones claimed descent from Manius Acilius Glabrio, the consul in 191 BC, and their claim was seemingly well-known, as the third-century historian Herodian discussed another member of the family, Marcus Acilius Glabrio (consul of 186)
> This Glabrionus was the most nobly born of all the Roman aristocrats, for he traced his ancestry to Aeneas, son of Venus and Anchises, and he had served two terms as consul.
Cameron however points out the obvious problem, since we know of no-one from this family between yet another Marcus Acilius Glabrio (consul of 256) and Sibidius in the late fourth/early fifth century (though there is an unknown Acilius Glabrio from an inscription in the early fourth century). For a family to pass their name through their male line for five centuries is extraordinarily unlikely (see for instance the often-noted longevity of the House of Capet in France - which is only frequently pointed out because it was so exceptional), so it would be safe to presume that descent from a female line and/or forged ancestries were involved somewhere along the way.
There were of course many other claims. Lucius Aradius Valerius Proculus Populonius, prefect of Rome in 337/8, was for example praised by a friend to be descended from the Poplicolae family active during the Republic, whilst the fourth-century inscription of Creperius Amantius and Caeionia Marina declared their descent from Munatius Plancus Paulinus, consul in 13 AD. The Decii and Corvinii, both families active at the same time as the Anicii, similarly had their Republican ancestry praised by Cassiodorus and Ennodius, two authors writing in Ostrogothic Italy in the sixth century (interestingly, the Anicii were not praised in relation to their Republican ancestors here). Personally, the most fascinating theory is the idea that Emperor Anastasius (491-518) was a descendant of Pompey the Great, as the Republican general was mentioned a few times in panegyrics dedicated to the emperor and the name 'Pompeius' is attested within the emperor's extended family - which is an indication that the family held the name to be somewhat important to pass on through the generations.
Understandably, despite all these claims, we have to be cautious, since we are reading what these families and their allies want us to read, not factual reports of their descent. The Romans loved everything from the past and evidently fictional ancestries were omnipresent. St Jerome for instance celebrated his patron Paula's descent from Agamemnon from the Trojan War, whilst Ruus Volusianus was allegedly descended from the Volusus featured in the *Aeneid*. Most famously, Constantine the Great (306-337) manufactured an entirely fictitious familial connection with the relatively recent emperor Claudius Gothicus (268-270). There is no reason for us to think that other Roman aristocrats were not capable of writing similar fabrications. Many people no doubt believed that they had many illustrious ancestors, and in reality they probably did, as they no doubt were all descended in some way from Roman families dating back to the Republic, but we have to be very cautious about their claims that they were descended from specific individuals, since the evidence available is not enough for us to test any of them.
| [
"After the fall of the Roman Empire, these families survived during the middle ages (c700-1200AD) perhaps under Papal rule in Rome. It is possible that branches of this family lived in Byzantine territories.\n",
"From these middle age families, originated the more modern families of the Roman nobility (1200-1600)... |
it’s so important that we keep our hands washed, but our housecats literally touch their waste and don’t wash their paws. why is this ok? | Until the 20th Century it was not common for people to wash their hands so often. But we have decided that we really don't like getting sick as much as older generations, or as cats do. | [
"Hand hygiene is defined as hand washing or washing hands and nails with soap and water or using a water less hand sanitizer. Hand hygiene is central to preventing spread of infectious diseases in home and everyday life settings.\n",
"For hand care they are designed to protect against the harm from detergents and... |
why do some people get off on being angry all of the time? what does it do for them? | Sometimes it is a defense mechanism. I've seen angry people use a general anger-filled disposition to hide insecurities and in doing so they become highly irrational. | [
"Anger causes a reduction in cognitive ability and the accurate processing of external stimuli. Dangers seem smaller, actions seem less risky, ventures seem more likely to succeed, and unfortunate events seem less likely. Angry people are more likely to make risky decisions, and make less realistic risk assessments... |
Is there a point as the temperature drops that it stops feeling colder? in other words, once a certain temperature is reached does it all just feel the same after that? | You don't feel temperature directly, you feel the rate at which heat leaves your body. So it really depends on the material's heat conductivity and how it's arranged as a heat sink.
Generally, the rate of heat transfer is inversely proportional to temperature, all else equal, and since you can't reach absolute zero, there is no maximum rate of heat transfer. Thus, there is no limit to how cold things 'feel' in this sense, but you'd probably damage your nerves and skin before you got anywhere near that cold, so this isn't really a meaningful statement. At some point you'll just destroy your sense of touch, and it will feel very painful and quickly cause numbness, not a sense of coldness. | [
"After a certain period, an equilibrium is reached: the drop has cooled to a point where the rate of heat carried away in evaporation is equal to the heat gain through convection. At this point, the following balance of energy per interface area is true:\n",
"Because of this effect, the lowering of temperature in... |
what happens to all the bleach and washing liquids and chemicals we use. is any of it filtered out or degrades once it goes down the drain or are we simply polluting the seas? | Most of the harmful stuff is removed at a [wastewater treatment](_URL_0_) plant. Things like bleach and soap are fairly reactive, so they get filtered out pretty easily. Some other things (like motor oil or plastics) are more resilient, so they survive through treatment, though. Don't pour motor oil down the drain.
Edit: Cunningham's Law strikes again. | [
"A 1-in-5 dilution of household bleach with water (1 part bleach to 4 parts water) is effective against many bacteria and some viruses, and is often the disinfectant of choice in cleaning surfaces in hospitals (primarily in the United States). Even \"scientific-grade\", commercially produced disinfection solutions ... |
Were "perfume cones" a thing in ancient Egypt? | Yes, its pretty well accepted that the yellow and white cones seen in Egyptian art from the New Kingdom are cones of fat that were meant to perfume the person as they melted. However, they were only worn in scenes where people were meant to be enjoying themselves, like a feast or festival. They were also worn by both men and women in art. Of course, the frequency with which they would have been worn in real life and whether artistic depictions are completely accurate is up for debate, but the basic concept of perfumed cones is sound, as strange as it may seem to us. | [
"Traces of onions recovered from Bronze Age settlements in China suggest that onions were used as far back as 5000 BCE, not only for their flavour, but the bulb's durability in storage and transport. Ancient Egyptians revered the onion bulb, viewing its spherical shape and concentric rings as symbols of eternal lif... |
I've heard that the Y chromosome is shrinking. Is it true, and what does it mean for future generations? | talk presented by hhmi:
[youtube video](_URL_0_) | [
"By one estimate, the human Y chromosome has lost 1,393 of its 1,438 original genes over the course of its existence, and linear extrapolation of this 1,393-gene loss over 300 million years gives a rate of genetic loss of 4.6 genes per million years. Continued loss of genes at the rate of 4.6 genes per million year... |
How do we know this? - origins of elements from the periodic table. /physics/ | The Big Bang created everything. As it cooled down atoms formed. Most were hydrogen. Some helium and lithium fused as well.
Everything else is understanding supernovae and how stars die.. Most of those percentages are calculated guesses, not exact values though. Different types of supernovae have different end results. For example type 1a supernovae is a white dwarf siphoning energy from a companion star until it explodes, releasing all of the elements it created throughout its lifetime. Know that all smaller stars fuse only up to carbon, oxygen and maybe a bit higher. Larger stars only fuse up to iron, maybe a bit higher. This is because anything beyond iron actually requires rnergy to fuse instead of making it. So all elements beyond iron were created in massive star supernovae or stars colliding. | [
"There is currently no consensus on the placement of elements beyond atomic number 120 in the periodic table. The table below shows one possibility for the appearance of the eighth period, with placement of elements primarily based on their predicted chemistry.\n",
"The standard presentation of the chemical eleme... |
what is laveyan satanism | Anton LaVey basically made up a faith based on his Ideals. Taking the satan figure as a symbol of defiance from western religions.
Lavey did not believe in the existence of any god or gods, as such to him humans are animals that got smart, and should act in that way.
However he put into place 2 separate codes of conduct. rules for acting. As well as ritual magics. so it's a bit of a mess before he set up to split his own church into regional competing sub churches.
There is a shit ton on this area | [
"LaVeyan Satanism is a religion founded in 1966 by the American occultist and author Anton Szandor LaVey. Scholars of religion have classified it as a new religious movement and a form of Western esotericism. It is one of several different movements that describe themselves as forms of Satanism.\n",
"The Satanist... |
does software updates always increases its filesize? | No, sometimes a file is overwritten. So as long as the original file isn't saved as a backup, there's a chance that a 60gb game with a 12gb update will likely stay 60gb.
If a more efficient code is produced, you can get lower file sizes. Sometimes programs launch with really clunky code that works and is launched to meet a deadline while future versions have better streamlined code.
However it's far far more likely for a product to have an increased filesize simply because you're adding to the program rather than removing.
The most common thing you'll see where a software update reduces filesize is if you install a game with HD textures, but don't have a very good video card, then go into your settings and tell it to use regular textures instead of HD textures. You'll get 2 or 3gb update and you'll go from 50gb down to 32gb. | [
"A file's modification time describes when the content of the file most recently changed. Because most file systems do not compare data written to a file with what is already there, if a program overwrites part of a file with the same data as previously existed in that location, the modification time will be update... |
how is it possible that 50 cent who made $100 million from the sale of vitamin water, is bankrupt? | Saw a comment before that said some woman is trying to sue him for $5 million for who knows fucking what. They said its his business side and not his personal side. So he is still super rich, at least from what I know so far | [
"In May 2007, Vitamin Water was sold to The Coca-Cola Company for $4.1 billion. As part of his endorsement deal, Wright was given 0.5% of the company, and thus netted approximately $20 million from the deal.\n",
"In 2010, Null reported that he and six other consumers had been hospitalized for vitamin D poisoning ... |
How was lumber in the middle ages measured and cut? | Indeed, medievals liked their timber as square and smooth as we do.
I love [this manuscript illustration](_URL_12_), which comes from the [Bedford Hours](_URL_8_), a prayer book from ~1423 CE. It is supposed to depict the building of Noah's Ark, but it looks suspiciously like a timber-framed house. The artist clearly saw house construction and fudged it to be the Ark.
And for our purposes, the tools of house builders and shipwrights are the same: the Bedford Hours shows tools which we would recognize today: saws and adzes for cutting and rough straightening timber. You can see someone at the bottom drilling a hole, and someone drilling a peg-hole in the assembled timber-frame. Scattered on the ground are hammers, wood mallets, chisels, adzes and another type of saw: the frame or bow saw.
We see these tools again in another picture of a carpenter [here](_URL_11_). But this time he has badly injured himself while truing timber with an adze. This image is part of a set of painting by Antonio Vivarini from 1450; they illustrate the miraculous works of [Saint Peter the Martyr](_URL_3_). The description from the Metropolitan Museum in New York:
> This painting belongs to a series of eight scenes that would have been arranged around an image or statue of Saint Peter Martyr (1205–1252). Here the saint ministers to a youth who had kicked his mother and cut off his leg in remorse. A genial storyteller, Antonio sets the scene in a carpenter’s shop.
The clever Vivarini has given us a picture of the medieval carpenter's shop: the frame/bow saw again, a long plane, the adze, and various timbers leaning against the workshop walls.
Returning to the first picture of the bedford hours: in the bottom left corner is a carpenter working a large plane - the long soled planes are meant to flatten long lengths of wood. The wood he is working on is so large that it rests on the ground, and it's wedged in logs for stability so the planing is straight and true.
Now, look at [this guy](_URL_0_) working in the house itself. Hanging from his belt is a black object - an object which looks suspiciously like a windable chalk line reel for setting long, straight lines, something we still use today (if we can't afford a laser). Or it may very well be a windable cloth measuring tape.
You'll note that all the images are Christian motifs. Another one which provides us with lots of building techniques is the constructtion of the Tower of Babel. [Thisone](_URL_6_) shows us a 12th century depiction of levels, plumb bobs, and squares.
Now, if the carpenter wanted a polished surface he had other tools for the job. Below is a copy of a [post I did some time ago](_URL_2_):
----------------------
This is one of those weird bits of history that I have researched, going back to when my teenage interest in medieval history dovetailed with a passion for woodworking (see what I did there?).
Anyway, I recollect references to 3 types of 'sanding' of wood before the modern era: a sharkskin called dog shark or dog fish, certain silica-heavy rushes (stiff marsh grass) and leather or cloth impregnated with ground stone, perhaps carried with an oil.
As I said my 'research' was in libraries over 20 years ago and I remember finding it in a book about medieval building. I remember this because I was seriously stoked at digging something out of the stacks. Sure enough, tonight google found it for me in a reference to a reference. In this medieval terms reference book there is a word 'hundysfishskyn' in [Middle English Dictionary from University of Michigan](_URL_4_), and that points to the book I actually remember looking at: [Building in England down to 1540: a documentary history by Louis Francis Salzman](_URL_1_). Hundysfishskyn is houndfish or dogfish. Unfortunately Google doesn't seem have this book scanned in and available to look through. [But I found another web reference to the text](_URL_9_), take it for whatever it's worth to you:
& gt;L.F. Salzman in Building in England down to 1540: A Documentary History (Oxford: Oxford Univ. Press, 1952) mentions "sanding" using rottenstone, scouring rush (aka equisetum, horsetail fern, shave grass, etc.), or dog-fish skin. On the latter, Salzman notes receipts for "hundysfishskyn for the carpenters" (Westminster, 1355) and "j pelle piscis canini pro operibus stall" (Windsor, 1351).
As it turns out [Equisetum is known for scouring](_URL_5_).
So that's a 14th century reference. But wait, there's more!
In the same obscure web site above, there is a reference to the book [On Divers Arts: The Foremost Medieval
Treatise on Painting, Glassmaking, and Metalwork by a certain Theophilus of the 11th century](_URL_10_). This book is partially searchable and seems to turn up the reference to the same rush called shave grass for sanding wood; alas, Google does not preview anything but a snippet.
Incidentally, smooth polishing of fine wooden stringed instruments is still done the same today as it was in the baroque period: with rosen powder after shellac coats.
The above would all be final finishing. After hand planing surface imperfections can be removed with a [cabinet scraper](_URL_7_). If you've used a scraper before, you'll know the burr on the edge will give you a surface finer than sanding as it cuts the grain, not grind it down. Sanding 'fuzzes' the raw grain and so it's preferred for finishing coats that have stiffened the grain enough for the sandpaper to 'cut'. Scrapers are very old technology: basically a thin piece of steel with some flex. Some handplanes in museums carry confused labeling and are actually devices for holding the cabinet scraper: using a cabinet scraper for extended periods will burn your fingers. I have seen examples of cabinet scrapers dating back to the baroque period.
------------------------- | [
"Lumber's \"nominal\" dimensions are larger than the actual standard dimensions of finished lumber. Historically, the nominal dimensions were the size of the green (not dried), rough (unfinished) boards that eventually became smaller finished lumber through drying and planing (to smooth the wood). Today, the standa... |
how did "a/an" evolve from "one"? | It happened the other way around. Beyond that... let's talk about a few things about how the English Language developed. (This being ELI5, I'm oversimplifying a little bit because the *full* version is more complicated and, not being a specialist in the history of English, I don't even understand all of the details myself. But this covers the case you care about.)
Languages develop according to rules that apply in a mostly regular manner. One of the rules in the development of Old English to Middle English is that short vowels become long in one-syllable words. ("Long" here is literal; it means that it's pronounced for a longer period of time than if it were short. The modern English "long" and "short" vowels are totally different sounds that last the same amount of time, but they come from the literally long and short vowels of Middle English.) Another is that under certain circumstances the n sound disappears before consonants. Another is that, before n (and this happens before it goes away), long a becomes long o.
The Old English word for "one" is "an." In a lot of situations where it was just being used as an indefinite article, people seem to have treated it like part of the next word, which means it wasn't a one-syllable word and the a didn't become long. Since it wasn't long, it didn't turn into an o, but the n still disappeared before most consonants. By habit, that got generalized to dropping it before all consonants, giving us the pattern we're used to.
But when you emphasized the fact that you really mean the numeral, that you're using it to talk about the fact that there is specifically one of whatever, it got seen as a standalone word. There's no consonant after it now, so the n never goes away, but it's also a one-syllable word, so the a becomes long (you even see it written that way in late Old English texts), then becomes an o, giving Middle English one (in Middle English a silent e was sometimes used to show that the preceding vowel was long; many silent e's in Modern English weren't silent yet in Middle English, though). The fact that it's pronounced like "won" instead of like "own" is a little bit of a surprise, though.
Scots, by the way, derives from dialects of Middle English that hadn't undergone the change of certain long a's to long o's. That's why in Scots they say "ane" instead, which is also a clue that would help us know that the Old English word had an a rather than an o. (In fact we don't even need the hint, since Old English is a written language and we've got plenty of stuff in it to check, but that kind of thing helps affirm the validity of the methods by which we figure this kind of thing out for non-written ancestor languages.)
There's another word you didn't expect to be related, by the way - the Old English word "anlic", a compound of that same "an" and "lic," which is related to our word "like" but develops into the -ly suffix we use for adverbs, means something is somehow one-ish, which is to say that there's just one of it. In modern English, that becomes "only". (I assume the lengthening of the a, and hence it turning into a long o, is influenced by what was going on with "one" back when it was still obviously "one" with a suffix.) | [
"A new \"ā\" was formed following the shift from \"ā\" to \"ō\" when intervocalic was lost in \"-aja-\" sequences. It was a rare phoneme, and occurred only in a handful of words, the most notable being the verbs of the third weak class. The agent noun suffix *\"-ārijaz\" (Modern English \"-er\") was likely borrowed... |
finding and moving specific genes between organisms | Biology PhD student here. In the interest in ELI5ness and not writing a wall of text no one wants to read, I'll write an overview and let you ask if you want to me elaborate more on how any particular part actually works.
**Finding the gene:**
You sequence the genome of the organism (or part of it), at which point you can use known DNA sequence patterns to predict where the beginning and end of each gene is. As for identifying which gene does what so you know which gene you are interested in, there are loads of ways and a lot of research is basically just this process - I can elaborate on this if you want.
**Moving the gene:**
There is a technology called the [polymerase chain reaction](_URL_0_) (PCR) that can replicate a single specific gene in a whole mess of DNA a trillion times, so that the entire sample is effectively just that one gene. So you either extract the DNA from the organism with the gene or, more commonly, extract its RNA (essentially its "genes in use") and use an enzyme to turn it into DNA, then use PCR on the sample to copy your gene of interest a trillion times. Now you have obtained your gene.
The next step is to put your gene in a plasmid vector, which is a little circle of DNA that has been specially designed for this purpose (plasmids occur naturally in bacteria, but we have extensively modified them to serve our purposes). You use enzymes called restriction enzymes that cut DNA at specific sequences to cut open the vector and cut off the ends of your gene (in the PCR reaction, you can add restriction enzyme snip sites to the gene copies you make). A useful property of restriction enzymes is that the cuts they make stick back together, so if you cut the vector and cut the ends off your gene in the same test tube and then add an enzyme to heal the cuts, at a certain rate your gene will end up stuck in the vector, since its cuts matched those in the vector. Now you have your gene in a vector. We call this process "cloning" a gene, confusing all non-scientists who think of cloning as making identical animals.
Now you want to put the gene into a different organism. If all you want is for the gene to be working inside the new cells, and you don't care about actually editing their genome, you can just put the vector with your gene inside them and you're done.
If you want to integrate the gene into the genome of another organism, it's more complicated. A disclaimer here is that I've never personally done this, so I am less familiar with it than the earlier techniques. But basically if this is your end goal, you design your vector to have long stretches of DNA on either side of where you put the gene in that match long stretches of DNA in the genome of the organism you are putting the gene in. If you do this, once you put the vector inside the new cells, at a low rate their genome will "recombine" with the matching parts of the vector, exchanging their DNA for the vector DNA and moving your gene into them. This recombination is a natural process that occurs with long stretches of matching DNA in all living things.
A final note: you may notice that all the "putting the gene in the organism" stuff I described only really works for single cells. If you want to put the gene in the genome of a multicellular organism, you do what I described to a fertilized egg or very early embryo that will grow into the organism. If you want to modify lots of cells in a fully-grown multicellular organism, you usually use a virus. You put the vector inside the virus, and when the virus infects the organism's cells, it delivers the vector. This is pretty hard and most researchers just stick to single cells when moving genes around.
*****
Oh look, it turned out to be a wall of text anyways! In any case, if there is anything you are confused about or any part of the process you want explained in more detail, please ask! I'd be happy to elaborate. This stuff is super important and forms the basis of a lot of modern biological research. | [
"After the formation of the regionally specified anterior-posterior axis, genes must be turned \"on\" to form unique structures in specific regions. This is orchestrated via the homeobox (Hox) transcription factor signaling pathway. First identified in Drosophila by Edward Lewis who won a Nobel Prize for the discov... |
Who were the first Jamestown colonists? How were they selected? | While I can't speak to the specific members of the crew that first founded Jamestown, the initial motivations of colonists in the first half of the 17th century were as follows:
a) For the rich: A quick profit - either from gold or timber or soap manufacturing or exporting pitch, additionally many were hopeful of the western passage to China that never materialised.
b) For the poor the motivations are harder to discern considering the lack of the records that they were able to leave, but most were persuaded by the hellacious and over-blown propaganda at the time that portrayed Virginia as a paradise (one slogan ran "In Virginia land free and labour scarce, in England land scarce and labour plenty"); and considering the state of England's poor at the time it was not suprising that many would leave (although of course they were more or less deceived and the initial colonists died in huge numbers).
I think the specific motivations and lives of the specific Jamestown colonists could be hard to discern.
~~~~
Source: Mainly Brogan's 'The Penguin History of the USA' | [
"A project of the proprietary Virginia Company of London, Jamestown had been established by an initial group of settlers on 14 May 1607. This colony proved as troubled as earlier English settlements. Two return trips with supplies by Christopher Newport arrived in 1608, while another large relief fleet was dispatch... |
Does dust/particles on the glass affect space telescopes significantly and how is this problem addressed? | In general, no, dust on the mirror doesn't really affect the image produced by a telescope.
Most telescopes are focused at infinity, so a speck of dust sitting on the mirror won't actually be in the image plane. All it does is *very* slightly dim the entire image, since the tiny portion of the mirror covered by dust is no longer reflective, and thus can't add to the overall brightness of the image.
The only time it really matters (and thus the only time you should consider cleaning your main mirror) is if your mirror gets *really* dusty. In that case the image is significantly dimmed, and all the dust can start producing scattering, which adds an overall hazy quality to the image as photons are now steered from their nice focused path in random directions. In general, this takes about a decade for most ground-based research telescopes to get to this level of dust, and mirrors are usually then sent off for cleaning; in space, where the environment is much cleaner, you'll likely never see this level of dust.
Fun fact: Almost fifty years ago, the security guard at McDonald Observatory had a bit of a psychotic break one evening, and shot the telescope's main mirror several times with his gun, point blank. As a very thick piece of glass, the mirror did not shatter, but did end up with a few bullet holes. Just like dust, this really didn't end of affecting the telescope's image much at all, so they just blacked out the edges of the holes (to prevent scattering from the ragged edges of the glass around the holes), and went straight on using it as a research-grade telescope. [The bullet holes are still there to this day](_URL_0_). | [
"There is a further problem of glass defects, striae or small air bubbles trapped within the glass. In addition, glass is opaque to certain wavelengths, and even visible light is dimmed by reflection and absorption when it crosses the air-glass interfaces and passes through the glass itself. Most of these problems ... |
I've asked all over Reddit for help identifying this unknown object. Recently, someone said it was part of a WWII Cryptography Radio. Someone else commented that since it may have historical significance, I should ask for help here. | My father is a radio enthusiast who served as a 1st class radio operator during military service in 60ties' Czechoslovakia. Nowadays he likes to repair 20ties-40ties radios as a hobby.
He says that he's never seen anything like this in a radio and that he is sure that those objects were NOT a part of a radio. Since there is a robust VOICE/TONE switch, his guess is a siren/megaphone combo. | [
"In July 1945, Captain Benjamin M. Bradin entered the \"Führerbunker\" and discovered an original carbon copy of the Göring Telegram marked with an 'F' in a group of Hitler's papers that in later years were given to Robert W. Rieke, a professor of history at the Citadel.\n",
"During the Second World War, a captur... |
why do web pages viewed on mobile devices keep changing layout as they load, and then change again just as you try to tap a link after it seems like they were finished loading? | Main reason is asymetric loading of elements and bad programming.
In detail: The main goal of a mobile page is to load as fast as possible.
There are certain methods to achieve this. The two most important (for your question) are:
1) Load visible stuff first:
The first things that will be loaded are things you see when you open the web page. Everything "below the fold" (below the point where you need to scroll to see it) will be loaded at a later point.
2) Load bigger elements later:
Bigger elements, such as images, will be loaded last. So your initial page is loaded fast, and the rest comes at a later point.
Now to your problem with the layout changes:
Poor programming causes this. Normally you would place blank placeholders for big elements like images. For example: If you, as a programmer, know, that there is an image that is 500x500 pixel, you will reserve this 500x500 spot with a blank white space. So when the image loads (after the initial loading of the page) you can fill this blank space with the image, without destroying the layout.
OR you could use two different image qualities. Like one really low quality (and low filesize) one that loads when you open the page (in case the image is in your "initial load view") and when this initial load is over, you use your "normal" bigger size image to replace the old one.
Really sorry, for a non native speaker its kinda hard to explain this :( I hope you get my point. | [
"In many applications (e.g., web browsers), holding down the control key while rolling the scroll wheel causes the text size to increase or decrease, or an image in an image-editing or map-viewing program to zoom in or out, if such a feature is available.\n",
"Also, because the layout information may be stored ex... |
Why do amputees feel a part of the body even though it is physically not present? | It's called 'phantom limb syndrom' and is thought to be related to the the somatosensory system (the neuronal system that senses pain, amongst other things). It's currently thought that this system does not readjust appropriately when a limb is amputated. This results in the continued sensation of movement and pain in the neurones which would originally have connected to the missing limb.
Another speculation is that the somatosensory system does readjust, but inappropriately, and so sensation is still felt in the missing limb when other parts of the body are stimulated (eg face > look up Ramachandran's experiment).
A definitive cause is yet to be confirmed, but the above are current speculations!
:) (BSc hons neuroscience)
| [
"A large proportion of amputees (50–80%) experience the phenomenon of phantom limbs; they feel body parts that are no longer there. These limbs can itch, ache, burn, feel tense, dry or wet, locked in or trapped or they can feel as if they are moving. Some scientists believe it has to do with a kind of neural map th... |
The charger for my electric toothbrush has no metal parts that touch the toothbrush. How does it recharge? | Through [magnetic induction](_URL_0_). It's the same mechanism for [transformers](_URL_2_), the electrical circuits of which are not physically connected either. See [this diagram of a simple transformer](_URL_1_).
Basically, the electricity from the outlet is used to generate a magnetic field, which generates a current inside your toothbrush. | [
"Modern electric toothbrushes run on low voltage, 12v or less. A few units use a step-down transformer to power the brush, but most use a battery, usually but not always rechargeable and non-replaceable, fitted inside the handle, which is hermetically sealed to prevent water damage. While early NiCd battery toothbr... |
Do you get your memories back after electroconvulsive therapy? | With our current methods of ECT, memory loss is quite common. There are a lot of complex idiosyncrasies and variables that play into the pattern and permanence of memory loss (i.e., age, bilateral vs. unilateral ECT, number of ECT treatments, psychiatric diagnosis, length of the seizures, interval between ECT treatments, etc). However, in general this is the pattern that is most common in the research, and this is also what I see clinically:
* Patients typically have slight retrograde amnesia (i.e., loss of memories for things that happened BEFORE they started ECT treatment) and it's usually most significant for things in the days (maybe a week or two) leading up to the first treatment.
* There is near complete amnesia (and this would technically be anterograde) for the events on the day of an ECT treatment, as well as fairly significant anterograde amnesia for several days (maybe a week or two) following ECT.
* After the treatment ends, their memory functions return to normal (i.e., they are able to encode, consolidate, and retrieve new information just as they could before). HOWEVER, the time for which they were amnestic (i.e., The days before the treatment, the day of the treatment, and several days after the treatment) are completely forgotten, and will never come back to memory.
* It's important to understand that the memory system requires that you encode and consolidate information into memories in order for you to remember it (i.e., take information from your surroundings into your brain, and turn it into a long-term memory). ECT appears to disrupt that process. Therefore, if information is not encoded or consolidated into a memory, there is no information there to retrieve. Does that make sense?
Hope that helps, let me know if you have other questions. | [
"Therapists who subscribe to recovered memory theory point to a wide variety of common problems, ranging from eating disorders to sleeplessness, as evidence of repressed memories of sexual abuse. Psychotherapists tried to reveal “repressed memories” in mental therapy patients through “hypnosis, guided imagery, drea... |
How did the early advocates for LGBTQ rights in the US begin pushing their case? What were the methods of the earliest advocacy groups? | Great question! Before I get into it, I want to provide a little context. I've talked quite a bit on here about different understandings of 'homosexuality' throughout history. How sexuality was understood and conceptualized has changed dramatically over the course of history, although not in a linear or teleological fashion. When we use words like 'gay' or even 'homosexual' we situate our discussion in a particular time and place. The 'modern' homosexual-gay-lgbt-queer movement has its origins in late 19th and early 20th century Europe, where Karl Heinrich Ulrichs, Karl Maria Kertbeny, Magnus Hirschfeld, and others began to create a framework, and some of the corresponding vocabulary, for understanding 'new' ways of framing gender and sexual identity. In the US, we often use the end of the Second World War as a kind of point of demarkation between earlier notions of sex, gender, and sexuality and the more current frameworks. For that reason, I'm going to confine my answer to that period. Although there was a vibrant (and remarkably open) homosexual culture in the US from the late 19th century to the 1930's, there are so many substantial and important differences that it would be both challenging and potentially problematic to compare movements.
The main organizations of the post-WWII pre-Stonewall era were the Mattachine Society and the Daughters of Bilitis. Mattachine was more male-centered, although there were some mixed chapters. DoB was entirely lesbian. Both organizations were formed in the 1950's, at a time of reactionary social-sexual attitudes. Whereas there had been a certain kind of openness allowed by the different social-sexual frameworks of the pre-WWII period, gay life in the 50's and 60's existed almost entirely in the closet. Although both these organizations were created to advocate for gay and lesbian people, maintaining the privacy and anonymity of their members was an extremely high priority. The Mattachine Society was named after a medieval French fraternal organization known for their masks; the name was chosen to indicate the need for homosexuals to be 'masked' from society. The name 'Daughters of Bilitis' was chosen because it was deliberately vague. Members were allowed to use just their first name - or a fake name- at meetings, and their publication *The Ladder* frequently mentioned that the identities of it's members would be protected (although this did not prevent the organization from being infiltrated by informants who provided the names of members to the FBI and CIA.)
Because of the strongly homophobic social attitudes of the 1950's and 60's, organizations like DoB and the Mattachine Society had a limited influence. They did make an effort to inform and educate the public about gay and lesbian people, but the extremely high social risks associated with homosexuality made any kind of substantial political organizing a challenge. Bars provided their own kind of organized community, particularly for working class lesbians, gay hustlers, 'drag queens' and other gender and sexuality outlaws. The informal (and usually underground) networks created in bars were often far more influential and important that organized groups like Mattachine and DoB (which were small, operated primarily in cities and by mail, and largely made up of the upper middle classes.)
After the Stonewall Uprising in 1969, there was a new kind of openness in regards to sexuality. People began to come out in large numbers, and new organizations were formed to lend a voice to this new generation. There was a flurry of activity in the couple of years after Stonewall, and this saw the creation of two organizations - the Gay Liberation Front and it's offshoot the Gay Activists Alliance. Both organizations came to be mostly dominated by white, middle class, cisgender gay men, despite the large number of trans* or gender-nonconforming people of color involved in the Stonewall riots. Despite some exciting action at the beginning organizations fizzled out within a few years, and failed to create a cohesive movement. That's not to say that there wasn't a lot going on in the 1970's. Gay men created impressive social-sexual networks in the 'gay ghettos' found in most urban centers. Lesbians became involved in lesbian feminism and lesbian separatist communities. The National Gay and Lesbian Task Force and the Human Rights Campaign - two of the most prominent national LGBT groups today - were both formed in the 1970's as well. Although they both played important roles in regards to lobbying and political fundraising, it would taking time before political and social attitudes towards gays and lesbians shifted enough for those organizations to gain real political traction.
The 1980's brought the kind of change that allowed political organizations to enter the mainstream. AIDS brought homosexuality into the mainstream consciousness in a way that nothing else had done before. Groups like ACT UP, Queer Nation, and the Lesbian Avengers were formed to draw political attention to AIDS and Queer issues, and brought a huge amount of visibility to LGBTQ people. By the 1990's gay and AIDS organizations really started to have political and institutional power. As gay became increasingly accepted by the mainstream, these organizations were able to broaden their fundraising base and expand their organizational goals. In earlier generations gay, lesbian, and trans* advocacy groups were small, kept afloat by volunteers and in some instances a handful of wealthy members.
When it comes down to it, organizations in the formal sense, played a pretty minimal role in modern LGBTQ movements. Informal community networks - although harder to trace - were hugely important in creating the movement.
That was a lot of information! I hope that at least kinda-sorta answered your question. And now for a brief list of sources: *Odd Girls and Twilight Lovers* - Lillian Faderman, *Transgender History* - Susan Stryker, *Gay New York* - George Chauncey. | [
"The first LGBT rights organizations began to emerge in the late 19th and early 20th centuries. Early LGBT rights organizations were primarily research-oriented psychiatric organizations that took a sympathetic, rather than corrective approach to homosexuality. such as the Scientific-Humanitarian Committee (Wissens... |
how did the original mathematicians prove their formulas and theories, and to who? | To their own community of academics. But how far back are we talking? Ancient greece? Renaissance? Isaac Newton era? | [
"The formula was discovered independently by Leonhard Euler and Colin Maclaurin around 1735. Euler needed it to compute slowly converging infinite series while Maclaurin used it to calculate integrals. It was later generalized to Darboux's formula.\n",
"Mathematical analysis formally developed in the 17th century... |
How are we self aware? What does our self awareness come from? | This is an awesome question, and one that straddles the line between science and philosophy. The real answer is "we don't know" and there are fascinating arguments for multiple viewpoints (including arguments that run the spectrum from pure spirituality all the way to quantum physics.)
I'd recommend [this Wikipedia article](_URL_0_) as a starting point. Give yourself an hour or so to it through, follow a few inline links, external links and *see also*s, and prepare to spelunk the rabbit hole. | [
"Self-awareness is the capacity for introspection and the ability to recognize oneself as an individual separate from the environment and other individuals. It is not to be confused with consciousness in the sense of qualia. While consciousness is being aware of one's environment and body and lifestyle, self-awaren... |
why guitar hero / rockband died. | IMO it's because there isn't much room to expand on the core gameplay. Sure you can add more songs, but are you willing to spend another $50+ dollars on basically the same game? Not to mention that the equipment (guitar, drumset, etc.) can also rack up the price (some may say unnecessarily). Once everybody played Guitar Hero/Rockband, it lost the sense of novelty that first came with such gameplay. | [
"\"Guitar Hero II\" is the centerpiece of an episode of \"South Park\" titled \"Guitar Queer-O\", in which Stan and Kyle overindulge in \"Guitar Hero II\" and become treated as though they were real-life rock stars. The episode was first broadcast on November 7, 2007, ten days after the American release of \"Guitar... |
Were the Romans cynical about their downfall (or perceived downfall) as (some) tend to be today in America? Was there any "sky is falling" moments or movements? | Augustine's *City of God* was written as a response to the seemingly imminent collapse of the Roman Empire. The sack of Rome in 410 was traumatic to an extent that I think it is difficult for us to comprehend. Today we tend to shy away from pronouncement's like this one from 1905 that said "the Roman Empire was the civilized world; the safety of Rome was the safety of all civilization. Outside was the wild chaos of barbarism. Rome kept it back from end to end of Europe and across a thousand miles of western Asia" but that is absolutely how the Romans viewed it. St. Jerome, on hearing of the fall of Rome, said "The City which had taken the whole world was itself taken." It was apocalyptic in the most literal sense.
But it is still difficult to actually name the fall of Rome because none of the players involved were aiming for that. Alaric, who sacked Rome in 410, was a Roman military officer who was seeking recognition and reward. Odoacer, who is generally credited with the death blow, invaded because the Roman government would not grant him *foederati* status. However, everyone picking away at it and reaching for their share of the pie had the effect of destroying it. | [
"The popular view is that the fall of the Western Roman Empire caused a \"dark age\" in western Europe in which \"knowledge and civility\", the \"arts of elegance,\" and \"many of the useful arts\" were neglected or lost. Conversely, however, the lot of the farmers who made up 80 percent or more of the total popula... |
Was classical music by German composers less popular after World War II? | Not talking about symphony, because the real drama is at the opera, c'mon! The Metropolitan opera had been performing German-language opera since the 1880s. During 1914-17 the Met did German opera as usual, but when the US entered WWI in late 1917 they did cancel all German operas. [Check out the 1917-18 season.](_URL_2_) [German was reintroduced pretty quickly though.](_URL_1_) However during WWII [Wagner was performed without interruption, along with other German pieces,](_URL_0_) as well Italian operas. Some of this was due to censorship being seen as unpatriotic, but I mean, some of it's also just practical: you ban all German AND Italian operas for the season, what do you have left? You're probably going to be doing *Carmen* until you want to barf roses. *Madame Butterfly* did disappear during the war though, presumably due to subject matter and not language.
So, WWII opera didn't fight a war against Axis music per se, the real story is with the singers. During WWII the Met essentially could not hire any top global talent, as at that time the top singers of Italian opera were from Italy and were unable to leave Italy (the Fascists banned opera singers travelling without permission in 1939). Tito Schipa, famously, cancelled his contract with the Met in 1941 to return home to Italy for the war because he was a very loyal Fascist. Top Wagnerian talent was from Germany, so obviously also no dice there. So, the real change at the Met during WWII is they started hiring a lot more American singers instead of Europeans, which was taken to be very patriotic and much lauded at the time. As opera houses closed through-out a war-ravaged Europe, America was also framing itself as this last bastion of opera, and therefore the highest ideals of Western arts and culture. Which is also why the 1942-43 season was saved from getting canceled! Unsold tickets were also given to off-duty servicemen, which of course is mega patriotic. (This is also why Met dropped their dress code during the war, for the servicemen, and it has never returned!)
So yeah, by being the only ones doing opera AND doing it with American singers, they kinda got to trumpet the Met as this All-American institution during WWII, despite opera being an art form dominated by 2 Axis cultures. Sadly, ethnically German and Italian opera singers living and working in the US at that time also faced discrimination and pressure from the government, and later on after the war they still faced discrimination. Most notably Kirsten Flagstad when she returned to the Met in 1951, after leaving America for her home Norway in 1941, which was occupied by Germany at the time. She was seen as disloyal and her return was protested. But, other than challenging the ethnic makeup of who gets to be a Heldentenor and a Wagnerian soprano, WWII didn't have much lasting impact on German opera in the US!
This is from *Grand Opera, the Story of the Met* by Afron and Afron, which came out late last year. | [
"Composers writing after World War II had to find a way of coming to terms with the destruction caused by the Third Reich. The modernism of Schoenberg and Berg proved attractive to young composers, since their works had been banned by the Nazis and were free of any taint of the former regime. Bernd Alois Zimmermann... |
how did calling shotgun for a vehicle's front passenger seat begin? where did it come from? | The term calling "Shotgun" came from when stage coaches would transport money from bank to bank like in the old west movies. The person in the passenger seat would be holding a shotgun for defense against robbers. | [
"The expression \"riding shotgun\" is derived from \"shotgun messenger\", a colloquial term for \"express messenger\", when stagecoach travel was popular during the American Wild West and the Colonial period in Australia. The person rode alongside the driver. The first known use of the phrase \"riding shotgun\" was... |
how can my computer distinguish between my wifi and my neighbors wifi if they are both running on 2.4 ghz? | It isn't just your router! every Wifi device is listening and broadcasting to everything! It is really chaotic at the signal level. There are several tricks wifi routers use to get around this
1 collision avoidance - the devices actively try to avoid disturbing each other, and N routers (and high end N NICS) actively try to find better paths
2 Channel switching - this is normally manual, but the further your channel is from your neighbors, the better. once you are 5 stations away, you are totally clear of their frequency. Because ther are only 11 channels, you can only have 3 routers be completely clear of each other.
3 Frequency switching - N devices are dual band and can connect at 2.4 or 5ghz. In an automated setup (normally requering matching branded hardware) they may have routines for jumping up to 5ghz automagicaly when things get to crowded. 5ghz has other advantages as well, there is a lot more space because of the higher frequency, so more devices can be there. Plus, fewer devices are already there! most wifi devices and machines like microwaves cloud up the 2.4 band, but don't block the 5. So if you can, set everything to be 5.
4 tagging data (SSID and IP info) and simply sifting through it all- most of what is broadcast isn't going to be a problem for a modern router to simply hear and discard. EVERY wifi device is doing this. It isn't just your and your neighbor's router, all of the PCs are sharing the frequency space too. So a modern router is actually designed to listen to several devices every moment, a good N router can do over 20 (roughly 3-5 per antenna.) However, to give you high speed bandwidth (streaming) it has to focus at least one antenna for that computer, the antenna rapidly and simutainusly litsens and broadcasts. If you have a 4 antenna router, and 2 people watching HDmovies and one gaming, your router will have a harder time dealing with anamolous data and frequency disturbances, it also wont be able to cater to new people, this is when you see your bars suddenly drop and come back (assuming no software problems.) The router has to drop you to check signal quality, or maybe a computer tried to register into the network, during which it had to drop the quality of your frequency for a few seconds to handshake that (it probably also took your friend longer to login to the router, simply because it is not able to pay as much attention to general broadcast while prioritizing registered user data.) But if an N router has a mostly free antenna, it can use that to do a lot of it's work automagicaly.
The simplist way to avoid those problems is to set a max number of wifi users that can login at any given time, and maybe even bandwidth quotas (cap the bandwidth on your mom's internet box.) But at the very least, don't have more than 1.5 people per antenna (on an N router) if gaming, or 4 per if general office use.
If there are lots of devices (routers and pcs) near you, then you may want to use your router as if you have 1 less antenna, this will guarantee quality. For lower end/base routers you should do this anyway, because, even if they are N routers, they generally have at least one antenna that is not worth it (fixed/omni direction with poor or no signal shaping routines/abilities) but normally 2 or more are just crap.
More expensive routers use smarter software, faster processors and more advanced antennas so they can rapidly handle all the traffic and collisions while still offering you a quality connection.
More expensive NICS do similarly, and can even start having advanced antennas like mechanics and high end beam shaping.
In all cases for N, they also figure out what works, and hold to a routine till it doesn't. So, keeping your router and computer in the same place is a good thing. They basically figure out that if they operate together in a certain way, a lot of the noise is gone/managable, and make a list of the best patterns between them. When you move any devices in your home (computer and ones that simply disrupt the frequency) they have to readjust. That said, I think modern routers have that adjustment period below 15minutes for most situations. Again, high quality hardware improves their smarts and capabilities in this. It is a required capability of N routers, and N NICS are designed to provide important signaling information to assist. High end NICS have active shaping capabilities as well. Oh, ths is also a high power process (processor and signalling,) so moving your labtop around while on wifi will increase battery usage. | [
"One of the most common ways of creating a home network is by using wireless radio signal technology; the 802.11 network as certified by the IEEE. Most wireless-capable residential devices operate at a frequency of 2.4 GHz under 802.11b and 802.11g or 5 GHz under 802.11a. Some home networking devices operate in bot... |
Can humans be predisposed to enjoying warmer or cooler environments? | I've coupled several articles to get this conclusion, and therefore it could be a simplified conclusion: A person with two short (homozygotes) alleles of the upstream regulating region of the serotoninreceptor encoding gene (5-HTT) are likely to be more sensitive to all kind of stimuli, eg. cold temperatures. However, this genotype does also lead to other fenotypic traits such as anxiety-related personality traits. | [
"Humans inhabit hot climates, both dry and humid, and have done so for thousands of years. Selective use of clothing and technological inventions such as air conditioning allows humans to thrive in hot climates.\n",
"As in other mammals, thermoregulation in humans is an important aspect of homeostasis. In thermor... |
Under what conditions does matter emit light? | As far as I'm aware, in order for light (or other electromagnetic radiation) to come into being, an electrostatically charged particle needs to either *a) accelerate*, or *b) transition between states with different energies*.
I'm not very clear on how big the overlap between *a)* and *b)* is, but for a) I'm thinking of an unbound electron/proton/ion/etc. slowing down or turning in 'free space', while for b) I'm thinking of an electron bound to an atom moving from one atomic orbital to another with a lower energy.
All of the types of emission listed in the comments so far seem to boil down to these two situations: black-body radiation is just b) averaged over a bunch of atoms with electrons in different orbitals; bioluminescence/phosorescence/flourescence/stimulated emission/FRET all boil down to b), too; Bremhsstrahlung and Cherenkov and cyclotron radition fall under a).
In the case of b), what color is emitted depends on the difference in energies of the orbitals that the electron jumps between. In lasers and neon signs there are usually fairly few possible 'jumps', leading to very 'clean', identifiable colors. In blackbody-like emitters such as incandescent lightbulbs, there are lots possible jumps, leading to a mixing of lots of colors -- resulting in what we perceive as white. Heating various substances changes what jumps are possible/more likely, changing the mixture of colors that gets emitted.
Interestingly, you can change the distribution of colors emitted by a heated lump of matter not only by changing its temperature or the atoms that make it up, but also by changing its surroundings -- for example, putting it between a pair of mirrors.
Fake edit: I guess there's also *c) emission of radiation due to particle-antiparticle annihilation*, but as I know even less about that than the other two, I won't delve into it.
And naturally, if I'm wrong about any of this, feel free to correct me. | [
"At the end of the 19th century, light was thought to consist of waves of electromagnetic fields which propagated according to Maxwell's equations, while matter was thought to consist of localized particles (See History of wave and particle duality). In 1900, this division was exposed to doubt, when, investigating ... |
How much was crusader governance and culture in the Kingdom of Jerusalem influenced by local customs? | This is what I study in the real world, and partially what my thesis is about, so there’s a lot to say about it! Hopefully this answer doesn’t go on and on forever…I think I've written most of this in previous answers, so here they are, all collected in one spot.
The Frankish crusaders did try to import a European-style “feudal system” in some ways, but in other ways they also adopted local customs.
The most important thing to remember is that Jerusalem was much more diverse than France. It was more like Spain or Sicily, so they didn’t create a completely unknown type of society, but it wasn’t anything like France or England. In Jerusalem there were Greek Orthodox, Armenian, Coptic, Nestorian, Georgian, Ethiopian, Syriac, and Maronite Christians. There were also Jews and a small number of Samaritans. There were Sunni and Shi’i Muslims, offshoots of the Shi’i like the Druze and the Nizaris. Some Muslims and Christians were Arabs, some were Turks or Kurds. When the First Crusade arrived, there was a Sunni Abbasid caliph in Baghdad, but he was mostly just a figurehead, and political power was held by the Seljuk sultan. Several other Seljuk emirs and atabegs ruled the cities of Syria, somewhat independently.
In 1099, Jerusalem was controlled by Shi’i Fatimid Egypt. The Sejuks had captured Jerusalem from them in 1070, but the Fatimids took it back in 1098 while the Seljuks were distracted by the crusade, then the Fatimids lost it again to the crusaders in 1099.
We don’t really know how many people lived in the crusader states, but one estimate (by Josiah Russell) suggests that all of Syria had about 2.3 million people at the time of the crusades, living in eleven thousand villages. Three hundred and sixty thousand of them lived in the Kingdom of Jerusalem, and two hundred and fifty thousand of those lived in rural villages. (Probably, anyway - we really have no idea about actual numbers.)
According to the Persian traveller Naser-e Khosraw, who visited around 1050, the population of Jerusalem was about twenty thousand people, and the city was always full of Christian, Muslim, and Jewish pilgrims. Ibn al-Arabi, who visited Jerusalem only a few years before the crusaders arrived, mentions Sunnis living in Jerusalem, but says the cities along the coast and elsewhere in Fatimid Palestine were majority Shi’i. Christians and Muslims had lived together in Jerusalem until 1063, when they were segregated into separate quarters. The Christian community controlled the Church of the Holy Sepulchre, and, outside the city, the town of Bethlehem. The Holy Sepulchre had been destroyed by the Fatimids in 1009, but was rebuilt starting in the 1050s (and then the crusaders later modified it into its current structure in the 1150s)
Under the Muslims, Christians and Jews were dhimmis and paid a specific tax, the jizya. The cities were sometimes governed by a qadi (an Islamic judge) or a ra’is (Arabic for “head” or “mayor”), or more directly by a Seljuk or Fatimid governor. In rural areas there was also a semi-feudal system that the crusaders found familiar and easy to adopt: land was granted as an iqta' and revenue was collected by the muqta', who could rule the iqta' as an independent fief.
So, that was the situation that the crusaders found when they arrived in 1099. They were now the rulers of this complex, ancient society, and they didn’t really disrupt it too much. They left the agricultural system in place, and the tax system - but now Muslims had to pay the jizya to the crusaders. There were never enough Franks to displace all of the Muslim or eastern Christian leaders, so in all of the towns and villages under crusader rule, there were still qadis or ra’is. The Franks found it easy to adjust to the iqta’ system, so they simply interpreted an iqta’ as a fief and a muqta’ as the fief holder, who owed them taxes and services, just like a fief back in France.
They had their own system of fiefs on top of that - in Jerusalem, the king had four major vassals (the Prince of Galilee, the Count of Jaffa, the Lord of Sidon, and the Lord of Oultrejordain), and each of those fiefs had smaller fiefs of their own, and these were all governed by Frankish lords, but the villages and towns and farms within those fiefs were left to the Muslims or eastern Christians who already lived there.
Or at least, this is what we're told by one of the crusader lords, John of Ibelin, who was the Count of Jaffa. According to him the County of Jaffa was the most important one. Of course he would say that! It also looks like John of Ibelin was painting an incredibly idealized picture of how “feudalism” was supposed to work in Jerusalem, and not necessarily how it actually worked in everyday practice. Historians in the past usually took him at his word, so Jerusalem has been described as having some sort of “perfect” form of feudalism, but we don’t think of it that way now. “Feudalism” itself is a pretty questionable concept these days (there is a lot of info in the AskHistorians FAQ about that so check that out as well). But in Jerusalem, like in France or England, theoretically the king and his vassals collected taxes from the people who lived in their territories, and those people also owed them military service or some other kind of service. John of Ibelin even lists how many knights each fief owed to the king (he himself owed 100 knights), but again, that is probably an idealized picture.
The biggest difference in Jerusalem was that the fief holders didn’t always live in their fiefs. They tended to live in Jerusalem or Acre or one of the other major cities, and they collected income from their fiefs, but these were “money-fiefs” for them. There was a lot of agricultural land in Jerusalem, but it was also much smaller and much more urbanized than, say, the north of France were a lot of crusaders came from.
The crusaders were “Franks” so we tend to think of them as “French”, but there were lots of people from all over Europe: the chronicler Fulcher of Chartres, who participated in the crusade and spent the rest of his life in Jerusalem, lists French, Flemings, Frisians, Swiss, Germans, English, Scots, Italians, and Bretons, among probably many others. Fulcher famously wrote that:
> “…we who were Occidentals have now become Orientals. He who was a Roman or a Frank has in this land been made into a Galilean or a Palestinian. He who was of Rheims or Chartres has now become a citizen of Tyre or Antioch. We have already forgotten the places of our birth; already these are unknown to many of us or not mentioned any more. Some already possess homes or households by inheritance. Some have taken wives not only of their own people but Syrians or Armenians or even Saracens who have obtained the grace of baptism...People use the eloquence and idioms of diverse languages in conversing back and forth. Words of different languages have become common property known to each nationality, and mutual faith unites those who are ignorant of their descent...He who was born a stranger is now as one born here; he who was born an alien has become as a native.” (Fulcher of Chartres, pg. 271)
They all tended to congregate together in the cities, or in rural areas where fellow (eastern) Christians already lived. They didn’t really interact with the Muslims, but that’s probably how it was before the crusaders arrived as well. Everybody kept to their own villages and didn’t mix, so the crusaders did the same. The Franks also established new villages, which is sometimes considered an early form of colonialism. The most famous of these new settlements is probably Bethgibelin. The settlers at Bethgibelin came from:
> "...Auvergne, Gascony, Flanders, Lombardy and Catalonia. Generally, the largest number of European settlers...were from the central, southern and western parts of France, and a few also from northern Spain and regions in Italy. In Bethgibelin the other settlers were from nearby Latin villages..." (Nader, pg. 94)
The towns and cities, especially along the coast (Acre, Beirut, Tyre, etc) were also full of Italian merchants and settlers. The Italians were kind of a state-within-a-state, since they governed their own neighbourhoods semi-independently of the Frankish lords. They were responsible for overseas trade with Europe - we know basically everything that was imported and exported from the crusader states by Italian and Muslim merchants - they sold dates, onions, sugar, cinnamon, cardamom, nutmeg, linen, shoes, and hundreds of other products! Sugar was especially important - the Italians also ran sugar plantations and this was probably the first time Europe had seen sugar from cane plants. (They also traded “marshmallow” and “liquorice”, but those were medicinal plants, and not, as I like to imagine, the modern candy.) | [
"The Crusader period in the history of Jerusalem decisively influenced the history of the whole Middle East, radiating beyond the region into the Islamic World and Christian Europe. The Crusades elevated the position of Jerusalem in the hierarchy of places holy to Islam, but it did not become a spiritual or politic... |
What would it take for scientists or doctors to be able to see what a human is currently thinking? | We don't know yet -- that's what makes it research!
There are many people working on [brain-computer interfaces](_URL_1_) to try to develop algorithms to 'decode' brain activity. At this point, however, the outputs that can be measured are relatively crude, e.g., sending a signal of "up", "down", "left", or "right".
[This](_URL_0_) is probably one of the most promising achievement to date. The idea is to match patterns of brain activation, measured by fMRI, to known responses to a series of videos.
But this is still a *long* way from what you are suggesting, since:
* The method required hours of calibration for each individual participant.
* The researchers knew that the participants were watching one of a certain set of videos. The reconstructed images were then also based on those videos (i.e., which video did the brain activity most closely match), not just on the measured brain activity.
* The participants were watching a video, not just imagining something.
Probably the biggest challenge -- besides not fully understanding how the brain computes information -- is the fact that we don't yet have any imaging technologies with the spatial and temporal resolution necessary to reconstruct any detailed imagery or thoughts just from brain recordings. Supposing we could get a much more comprehensive read-out of brain activity, we could probably develop very detailed algorithms to pull out a lot of information using various signal analysis methods. Mind you, that in itself will be an enormous computational challenge, especially since any such algorithms will likely have to be trained for each individual before the outputs make any sense. | [
"Developments in technology and medicine mean that doctors and scientists can examine our brains in more ways and more detail than ever before, all without having to open up the body. In this issue, we explore how imaging research has changed the way we can look inside the human brain.\n",
"It has become possible... |
why is president obamas amnesty executive order being brought before the supreme court? | Reagan amnesty was a lawful compromise with Congress, tax cuts for so many immigrants. I am not familiar with any Bush amnesty so I decline to remark. Obama's executive amnesty otoh is a complete go around of Congress. Executive orders bear no legal weight, they are not law. They are directives to agencies of the executive branch. Once he leaves office, unless resigned by the next POTUS they become null and void. This is seen as an overstep by the executive branch into the legislative branch. | [
"Brown's dissenting opinion in \"Omar v. Harvey\" sets forth her judicial outlook on the constitutional balance of powers. The United States Court of Appeals for the D.C. Circuit upheld an injunction that forbade the U.S. military to transfer Omar, a suspected insurgent, out of U.S. custody while his \"habeas corpu... |
what incentivizes companies to raise wages? | When labor is short in supply, companies must increase wages to attract workers.
You can see this in (pre-oil-bust) Alberta, Canada. You can get paid $15/hr to be a Barista in Fort McMurray, while a few hundred kilometers away, in Calgary or Edmonton, they only make $10. Willing to do unskilled or trained-on-site physical labor? You could easily make $30/hr to start, which is unheard of in the bigger cities in Canada.
This would theoretically happen in a more widespread fashion if a nation nears full employment (less than 4% unemployment). As there are fewer and fewer potential candidates for each job, companies are willing to (or rather forced to) offer more money to try to lure workers. | [
"Advocates of unions claim that the higher wages that unions demand can be paid for through company profits. However, as Milton Friedman pointed out, profits are only very rarely high enough. 80% of national income is wages, and only about 6% is profits after tax, providing very little room for higher wages, even i... |
how does executive order qualify as constitutional and fall in line with the system of checks and balances? | Executive orders (at least in theory) don't grant the executive branch more powers, they work within the powers already granted to the President by the Constitution or by Congress. The courts can overrule an EO if it's overstepped its bounds, and Congress can pass a law overruling an EO if it's based in powers they delegated to the executive. | [
"The U.S. Supreme Court has held that all executive orders from the president of the United States must be supported by the Constitution, whether from a clause granting specific power, or by Congress delegating such to the executive branch. Specifically, such orders must be rooted in Article II of the US Constituti... |
why does the face of a golf club have lines on it? | The grooves are cut into the face of the club to increase the grip between the ball and the face. The puts a controlled spin on the ball, which makes the ball travel in a predictable path.
If the ball does not have a controlled spin, it will move in a random path as spin is created and lost as the ball moves through the air - kind of how a knuckleball drifts randomly in baseball. | [
"According to the rules of golf, all club grips must have the same cross-section shape along their entire length (the diameter can vary), and with the exception of the putter, must have a circular cross-section. The putter may have any cross section that is symmetrical along the length of the grip through at least ... |
what's the difference when a medication commercial says a child under 6 can't take it, and kids 6-18 should not take it? | Pediatric medication is weight-based, so for many medications, the dosage strength would have to be severely diluted to be usable for young children to avoid overdose. This is why certain drugs are good for certain age groups of children - the weight difference between an 11 yr old and a 5 yr old, for example.
Other factors come into play as well. The structure of medication (liquid vs tablet vs capsule vs a crushed tablet/split capsule can affect how fast a drug works or how easily it can be ingested down tiny throats.
| [
"While they have been used by 10% of American children in any given week, they are not recommended in Canada or the United States in children 6 years or younger because of lack of evidence showing effect and concerns of harm. One version with codeine, guaifenesin, and pseudoephedrine was the 241st most prescribed m... |
why do my ears tickle/itch when listening with headphones? | I'm not a doctor, yet, but every time I have experienced something similar to this, and found that I have the option of "scratching" it as best I can or turning down the volume. I think that the itch is a response to inner ear damage, because every time I have turned down the volume the itch goes away on its own after a moment.
This may not be the case for you, hopefully, but try reducing the volume next time instead of scratching and see if that works. Call it an experiment that may save your hearing later on. | [
"Supra-aural headphones or on-ear headphones have pads that press against the ears, rather than around them. They were commonly bundled with personal stereos during the 1980s. This type of headphone generally tends to be smaller and lighter than circumaural headphones, resulting in less attenuation of outside noise... |
why do you say "a european" and not "an european" | You use an when the beginning *sounds* like a vowel regardless of if it is one. European starts with a "y" sound which in this case counts as a consonant.
Edit: another example you would say "an hour" because the h is silent. | [
"The term \"Europe\" may be used in one of several different contexts by British and Irish people: either to refer to the whole of the European continent, to refer to only to Mainland Europe, sometimes called \"continental Europe\" or simply \"the Continent\" by some people in the archipelago. \"Europe\" may also b... |
why is pre-made food cheaper than the ingredients? | Especially when talking about fresh ingredients, it's because there's a lot of waste.
Frozen pizza has a huge shelf life, so if a store buys 100 of them, they're going to sell 100 of them. If a store buys 100 tomatoes, they're probably going to sell 60-70, and the rest will end up in the trash because they're not pretty enough, bruised or rotten. That instantly makes the good tomatoes 50% more expensive.
The same happens at the wholesale stage because a truck may have been sitting in customs for too long, they weren't stored properly at some point, or the wholesaler bought too much and couldn't resell them in time.
So when you buy one tomato, you're also paying for the other two that the farmer, wholesaler or grocer had to throw away somewhere along the way. | [
"As often happens with gourmet recipes which become popular, the ingredients that were rare, expensive, seasonal, or difficult to prepare were gradually replaced with cheaper and more readily available foods.\n",
"Bread, cheese, salted food and other prepared foods have been sold for thousands of years. Other kin... |
how long do you have to stop drinking for your tolerance to alcohol to go down to that of a new drinker's? | I ACTUALLY KNOW THE ANSWER!!! It will never go back down to that tolerance. Tolerance is built by your brain being conditioned to react to alcohol. The time varies from person to person to get close, but that could be 6 months to 5 years.
So let's say the first drink you ever had was in a bar, when you were wearing a blue shirt, standing with three friends, out of a shot glass, at 5pm.
If every single day for 30 days you have a drink the same exact way, by the 30 day mark you will have built up a significant tolerance. That's because all of those factors will alert your body that you're about to start drinking and your body starts acting as if it is about to start breaking down alcohol before you even start drinking to keep your body at homeostasis.
Now obviously that's now how you drink because it won't be exactly the same every time so that would be a very strong association, but your body does know when it's about to drink because we are creatures of habit and largely drink in the same way every time. So when you're at the bar or a club where you normally drink, your body will start working toward eliminating the substance. When you're even thinking about it it will happen.
Now let's say you stop drinking. You still go to the bar and with your friends and all the usual places and times you used to drink pass by. Your body will then start going through extinction where the conditions that used to alert your body that you're about to drink will no longer result in drinking and therefore you don't need to start working toward eliminating the drink from your system.
And tl;dr finally, even if you stop drinking for 50 years after building up a high tolerance, your body will later react in the same way as it did before and start working toward eliminating the substance even before you drink it because of something called spontaneous recovery.
That's where a previously conditioned stimulus regains its conditioned response after extinction. **Edit: After those 50 years you do still have some tolerance but it will not be as strong as your tolerance the last time you drank.** This is because a body that has never drank has no idea how to handle alcohol, but a body that has drank obviously does and your body will begin to take the steps immediately instead of trying to figure out how to do it later.
If you want to simulate this effect, go drinking in a way that you don't normally drink. Drink spontaneously and your body will be surprised into drinking and the reaction will be delayed.
There's a lot of research on tolerance and heroin done with mice on the topic of classical conditioning. This explains why people overdose. When you do heroin at home 50 times, your body needs more and more every time because your body is breaking it down before it gets in your system. So when you do it the 51st time in a place you're not familiar with (a hotel room for example), you do that same large amount, but your body did not prepare for it to take in heroin so it doesn't get to fight off the drug before it gets injected. | [
"The Ministry of Health and Medical Education has developed a national programme to reduce alcohol consumption by 10% between 2015 and 2025, but the religious-driven zero-tolerance alcohol policy impedes the development of an effective harm-reduction approach.\n",
"The consumption of alcohol itself is not conside... |
in determining blood type, the o allele is recessive to both the a and b alleles. why is it then that o is the most common blood type and it's prevalence hasn't declined? | So this is an interesting question. If I recall correctly from school, type O is what the earliest people had (postulated). Over time mutations have occurred leading to difference surface antigens like the A and B antigen. So while they are recessive, there are still many people with this. If two people who are both O get together and have a baby every single one of them will be type O. But is someone who is AO mates with a BO, they have a chance of creating a O as well. So you can see how they won't be totally phased out. | [
"Some evolutionary biologists theorize that there are four main lineages of the ABO gene and that mutations creating type O have occurred at least three times in humans. From oldest to youngest, these lineages comprise the following alleles: \"A101/A201/O09\", \"B101\", \"O02\" and \"O01\". The continued presence o... |
The big bang theory is the accepted theory for the genesis of the universe. I've always accepted and (I thought) understood this as a scientific theory. How does this theory justify/explain the creation of something (spacetime, matter) out of essentially nothing? | No, that is not what Big Bang Theory is. It's a common misconception. Big Bang Theory is about the state of the very (very) early universe and how it evolved from that. It is *not* a theory about how or why the universe got here in the first place. I'm not saying that's not a valid question, I'm just saying that's not what this particular theory is about.
There's no broadly accepted theory on how we got to that point. | [
"The Big Bang itself is a scientific theory and as such stands or falls by its agreement with observations. However, as a theory which addresses the nature of the universe since its earliest discernible existence, the Big Bang carries possible theological implications regarding the concept of creation out of nothin... |
what does it mean when a cough “moves into your chest”? was it somewhere else before? | People generally say that in references to colds.A “cold” is a blanket term for any viral infection of the nose and throat. In the early stages of a cold, your body is fighting the cold directly and most of the symptoms are in your sinuses, nose, and throat.
After a few days the virus is pretty much dead and the nose starts to feel better, but at that point so much mucus has drained down your throat that you start coughing to clear it out. So it feels like the cold has moved from your nose into your chest, when in reality the chest symptoms are your body cleaning up after the cold. | [
"A cough is a sudden, and often repetitively occurring, protective reflex which helps to clear the large breathing passages from fluids, irritants, foreign particles and microbes. The cough reflex consists of three phases: an inhalation, a forced exhalation against a closed glottis, and a violent release of air fro... |
Is there any evolutionary benefits other than sexual selection in having blue or green eyes instead of brown? | Like skin tone, lighter eye color is simply a reflection of lower pigmentation (less melanin). As with many genes, if those genes that influence eye color can mutate to less active forms without dicouraging the survival of a given organism, they may continue to mutate to less and less active forms. This means that if higher pigmentation isn't all that advantageous to some animal, lower pigmentation may result.
There may be a selective factor at work, however: lighter skin tone was favored for north-dwelling human ancestors because it generates more vitamin D (which, closer to the equator, would have been supplied by the abundant sunlight). Because some of the genes that govern skin and eye pigmentation overlap, lighter eye color may have been coincident with lighter skin color. | [
"All three colours have evolutionary advantages in different ways. While yellow females have higher fitness due to their large clutch sizes, orange females enjoy high fitness due to their large body size and increase competitive advantages. Mixed females exhibit both of these advantages.\n",
"While sexual selecti... |
why do these videos of opening kinder eggs receive hundreds of millions of views. | Because kids love to watch them being open and seeing what surprises are in them, even if they aren't getting the toy. | [
"The Eggs is an Australian children's animated television program that first screened on the Nine Network in 2004. There are 52 episodes of 12 minutes duration. Two episodes are usually screened together in a half hour timeslot.\n",
"Numerous easter eggs have been found in the digital files for \"Mouth Sounds\" a... |
what's the difference between embezzlement and theft? | Embezzlement is taking funds that you been entrusted with, and converting them to your own use. Theft is just taking property to which you are not entitled.
So, Janice is a teller at a bank. She's required to keep a drawer full of cash, count it, dispense it to customers as needed, etc. That money has been entrusted to her, so she's given access to it. If she were to take $20 from that drawer for herself, that'd be embezzlement. If she were to go into the McDonald's across the street and take $20 from their till while someone wasn't watching, that'd be theft. | [
"It is important to make clear that embezzlement is not always a form of theft or an act of stealing, since those definitions specifically deal with taking something that does not belong to the perpetrators. Instead, embezzlement is, more generically, an act of deceitfully secreting assets by one or more persons th... |
Would I measure the generated magnetic field of a charged particle, if I am moving alongside with it? | The fields produced by a point electric charge moving arbitrarily are given [here](_URL_0_). If you assume that the particle has no magnetic moments, these are the only fields it will produce. If you look at the magnetic field equation, it looks complicated, but you can see that the whole thing is zero if the speed of the particle is zero. So in an inertial frame in which the particle is at rest, the magnetic field that it produces is zero. | [
"A charged particle moving in a -field experiences a \"sideways\" force that is proportional to the strength of the magnetic field, the component of the velocity that is perpendicular to the magnetic field and the charge of the particle. This force is known as the \"Lorentz force\", and is given by\n",
"Any charg... |
What are the best books or online resources for acquiring a pre-Federalist Papers understanding of the debates of the United States Constitutional Convention? | The [Avalon Project](_URL_2_) at Yale is one place where you can find many of primary sources related to the topic you are interested in.
In addition, [this website](_URL_0_) also provides numerous documents.
Lastly, the [Liberty Fund](_URL_1_) also contains numerous sources that touch on the Revolutionary period.
Each site contains a treasure trove of unedited transcribed documents that detail the lead up to the revolution, the formation of the Articles of Confederation, and extend beyond the Constitutional Convention.
Hope this helps.
| [
"BULLET::::- Story, Joseph (Mar 26, 2008) \"Commentaries on the Constitution of the United States: With a Preliminary Review of the Constitutional History of the Colonies and States Before the Adoption of the Constitution 4th Edition\" (2 volumes) (March 26, 2008) with Notes and Commentaries by Cooley, Thomas M. (C... |
why are france and spain 1 hour ahead of the uk when part of those countries are directly below us? | Because Nazis.
They used to be in the same time zone as the UK. But then when the Nazis took over France in WW2, they switched them to the same time zone as Germany.
Spain wasn't directly involved in WW2, but were on fairly good terms with the Nazis so also switched to have a matching time zone to aid cooperation.
For both it turned out to be more convenient after the war was over so they stayed that way. Now they all work quite closely together, and people and goods cross the borders all the time, so it's easier to be in a single time zone. | [
"Tourist links between the two countries are significant, with over 400,000 Australians visiting France each year. Almost 98,000 visitor visas were granted to French nationals to visit Australia in 2005–06, making France the 10th largest source of visitor visa grants, and 1,867 student visas were granted. A working... |
if we can achieve every existing color by mixing the basic ones, why do cymk and rgb look different? | Red, green, and blue (RGB) are the primary colors for **light (i.e., additive color)**. In this case, "black" is the absence of any light, and "white" is 100% of all three colors.
Cyan, yellow, and magenta (CYM) are the primary colors for **pigment (i.e., substractive color)**. In this case, "white" is the absence of any pigment, and "black" is 100% of all three pigment colors. Each of these pigments get their color from absorbing one of the primary light colors, and reflecting the other two. Thus cyan is the mix of green and blue (absorbs red), yellow is the mix of red and green (absorbs blue), and magenta is the mix of red and blue (absorbs green).
The "K" in CYMK is "black". Printers will often add a separate reservoir of black ink for darker shades of color and for black & white printing.
**EDIT:** Bolded some terms and added language for clarity. | [
"In modern color theory, also known as the RGB color model, red, green and blue are additive primary colors. Red, green and blue light combined together makes white light, and these three colors, combined in different mixtures, can produce nearly any other color. This is the principle that is used to make all of th... |
Any good books on Stone Age? | Although it is not a book about the Stone Age, Ian Morris's book *Why the West Rules -- for Now* spends several chapters on prehistory as part of a sweeping treatment of the entire history of East and West.
Otherwise, I suggest asking this on /r/AskAnthropology. | [
"Other depictions of the Stone Age include the best-selling \"Earth's Children\" series of books by Jean M. Auel, which are set in the Paleolithic and are loosely based on archaeological and anthropological findings.\n",
"Back to the Stone Age is a novel by American writer Edgar Rice Burroughs, the fifth in his s... |
why do people have the urge to grab cute babies' cheeks and smush their face? | [This article explains why.](_URL_0_) TL;DR "Cute Aggression" is the brains response that could be protective, or a way of venting extreme feelings of giddiness and happiness | [
"A \"kunik\" is a form of expressing affection, usually between family members and loved ones, that involves pressing the nose and upper lip against the skin (commonly of the cheeks or forehead) and breathing in, causing the loved one's skin or hair to be suctioned against the nose and upper lip. A common misconcep... |
the concept of wells/underground water. is there just water everywhere beneath our feet that we can access as long as we dig/drill far enough down? | Technically yes. There are a few types of underground water supplies. The first is the water table.
When it rains where does that water go? Well you do see most of it run down the sidewalks, and streets. Where does the rest go? Underground of course. It drains through cracks, and soft soil till it reaches the point of saturation. The bottom of that point is the water table.
For example this water table is at 75ft. You take a drill,or even shovels, and started digging a hole you will hit water (depending on the last good rain) anywhere from just below the surface of top soil to 75ft. Where you place the pump in that type of well will give you so much water. If you go into a drought that type of well goes dry rather quickly.
The second type of underground water supply is an aquifer. Aquifers are deep. My example will be the one near me in San Antonio Texas. Surrounding San Antonio you have rivers. Comal, Guadeloupe, San Antonio, etc. They start in the hills, and flow down to the sea.
Rivers are the blood vessels of the earth. What you see on the surface is just one vain. Underneath them in the cracks in the bedrock are the rest.
All that water from the rain that didn't soak into the ground runs off into the creeks that supply most of the river's water. As time goes on between rain storms the upper layer of soil drains the rest of the water tables into the river. Then the river supplies the underground aquifer.
The San Antonio aquifer is larger than the city itself by hundreds of square miles. Test wells drilled into it at several locations is how it is measured. Every night the local weatherman on the news will tell you what the level is. On average it is around 640 feet.
The water dept keeps an eye on that daily to make sure the population and agriculture have adequate allocations. If it gets low you have restrictions put in place. Like not watering your lawn on certain days. To extreme examples of limiting total number of gallons used per day.
Sorry if I put you to sleep. I know a five year old would be. | [
"A water well is a mechanism for bringing groundwater to the surface by drilling or digging and bringing it up to the surface with a pump or by hand using buckets or similar devices. The first historical instance of water wells was in the 52nd century BC in modern-day Austria. Today, wells are used all over the wor... |
was there a large difference between various Native American tribe creation myths? | Most tribes had their own unique myths but most of these myths shared many common themes. In North America in particular, a common theme is the idea of humans climing out of a dark, shadowy underworld into the earth. In this view life originated in the underworld and at some point for some reason they found their way out, often times by climbing a tree or vien (I cannot remember the explanation as to why they finally found the way out but in many cases thier is a reason). Also in this world view, the world is believed to be in teirs (an underworld, the earth, the heavenly world above them).
Another common creation myth (particularlly in the North West) was the idea that a creator god formed man out of clay. I can remember one myth in which the creator god did this but that old trickster Coyote distracted god and made him burn the people, they were sent to Africa. God tried again but Coyote made god take them out before they were ready, they were sent to Europe. The ones who came out just right were Native American. (Many creation myths were revised after the arrival of Europeans)
Another common theme in these myths were animals with human and spiritual features.
Sorry I could not get into any real detail or provide sources im in a bit of a rush and its been a while since i studied the Native Americans.
Mythology is a very interesting subject though, especially cosmology. When studied on various levels these myths reveal all different types of ideas and beliefs that a culture had. Another interesting note is many cultures from across the globe share many similarities in their cosmology. Sometimes its uncanny and it will give you an interesting perspective on human nature.
If you want to further research this a simple google search will provide you with many native American myths. For the study of mythology and cosmology in gerneral I would recoment the books "Cosmos and Chaos" by Norman Cohn or "The Sacred and the Profain" by Mercea Eliade | [
"Native American cultures are numerous and diverse. Though some neighboring cultures hold similar beliefs, others can be quite different from one another. The most common myths are the creation myths, that tell a story to explain how the earth was formed, and where humans and other beings came from. Others may incl... |
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