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why do my joints hurt during menstruation? | Estrogen affects joints by keeping inflammation down and estrogen levels decline during menstruation. | [
"The menisci act as shock absorbers and separate the two ends of bone in the knee joint. There are two menisci in the knee, the medial (inner) and the lateral (outer). When there is torn cartilage, it means that the meniscus has been injured. Meniscus tears occur during sports often when the knee is twisted. Menisci injury may be innocuous and one may be able to walk after a tear, but soon swelling and pain set in. Sometimes the knee will lock while bending. Pain often occurs when one squats. Small meniscus tears are treated conservatively but most large tears require surgery.\n",
"Many women experience painful cramps, also known as dysmenorrhea, during menstruation. Pain results from ischemia and muscle contractions. Spiral arteries in the secretory endometrium constrict, resulting in ischemia to the secretory endometrium. This allows the uterine lining to slough off. The myometrium contracts spasmodically in order to push the menstrual fluid through the cervix and out of the vagina. The contractions are mediated by a release of prostaglandins.\n",
"Many women experience painful cramps, also known as dysmenorrhea, during menstruation. Pain results from ischemia and muscle contractions. Spiral arteries in the secretory endometrium constrict, resulting in ischemia to the secretory endometrium. This allows the uterine lining to slough off. The myometrium contracts spasmodically in order to push the menstrual fluid through the cervix and out of the vagina. The contractions are mediated by a release of prostaglandins.\n",
"Other structures within the joint can also be affected. The ligaments within the joint become thickened and fibrotic and the menisci can become damaged and wear away. Menisci can be completely absent by the time a person undergoes a joint replacement. New bone outgrowths, called \"spurs\" or osteophytes, can form on the margins of the joints, possibly in an attempt to improve the congruence of the articular cartilage surfaces in the absence of the menisci. The subchondral bone volume increases and becomes less mineralized (hypomineralization). All these changes can cause problems functioning. The pain in an osteoarthritic joint has been related to thickened synovium and to subchondral bone lesions.\n",
"Menstrual cramps are one of the most common side effects of vasocongestion in adult females. Although pain and discomfort varies among individuals, vasocongestion is an essential part of the shedding of the lining of the uterus. Abnormal vasocongestion during the menstrual cycle can lead to irregular bleeding, severe and debilitating cramps and anemia caused by increased menstrual flow.\n",
"The menisci are the other intra-articular structures that help to stabilise the joint and help to distribute load evenly across the surfaces; these are crescent-shaped discs of cartilage facing each other from side to side across the joint. They are thicker at the outside and with a thin inner aspect and they also have nerve fibres that help to tell the brain how much load is getting transmitted through the joint. The medial (inside) meniscus is often damaged with a long-standing cruciate ligament rupture because it is firmly attached to the tibia and gets crushed during abnormal cranial movement of the tibia. The lateral (outside) meniscus is more firmly attached to the femur and does not get crushed.\n",
"A combination of postural changes, baby, unstable pelvic joints under the influence of pregnancy hormones, and changes in the centre of gravity can all add to the varying degrees of pain or discomfort. In some cases it can come on suddenly or following a fall, sudden abduction of the thighs (opening too wide too quickly) or an action that has strained the joint.\n"
] |
Are the busts of Roman leaders like Caesar taken from death masks or are they impressions crafted from contemporary descriptions? | Follow up query; Octavianus, Trajan and even Constantine I had a bust, however Basil II did not. At what point did they stop producing busts for each emperor and move towards using mosaics like that of Zoe and Constantine IX or Ioannes II Komnonos at the Hagia Sofia? | [
"Historians and archaeologists not affiliated with the French administration, among them Paul Zanker, the renowned archaeologist and expert on Caesar and Augustus, were quick to question whether the bust is a portrait of Caesar. Many noted the lack of resemblances to Caesar's likenesses issued on coins during the last years of the dictator's life, and to the Tusculum bust of Caesar, which depicts Julius Caesar in his lifetime, either as a so-called \"zeitgesicht\" or as a direct portrait. After a further stylistic assessment, Zanker dated the Arles-bust to the Augustan period. Elkins argued for the third century AD as the \"terminus post quem\" for the deposition of the statues, refuting the claim that the bust was thrown away due to feared repercussions from Caesar's assassination in 44 BC. The main argument by the French archaeologists that Caesar had founded the colony in 46 BC proved to be incorrect, as the colony was founded by Caesar's former quaestor Tiberius Claudius Nero on the dictator's orders in his absence. Mary Beard has accused the persons involved in the find of having willfully invented their claims for publicity reasons. The French ministry of culture has not yet responded to the criticism and negative reviews.\n",
"There is widespread agreement that the individual depicted by the bust is the Roman politician Gaius Julius Caesar, who was one of the most significant figures in the end of the Roman Republic in the first century BC. The only known portraits of him that derive from his lifetime are those on his coins, which are barely idealised and depict him with clearly unique features. They stand entirely in the Republican tradition. All known sculptural portraits were created only after his death. The Green Caesar belongs to a group of late Republican portraits which appear very individualised to the modern viewer, but actually just reproduce various idealised features. These depictions represent values and qualities which were expected of the statesman, using typological forms and normalised formulae. Thus the signs of old age indicate authority (\"auctoritas\"), while the gaze and expression show dignity and strictness (\"gravitas\" and \"severitas\") and the tilt of the head shows dynamism and vigour. The viewer sees a serious and dignified man who is fully aware of his position and the duties that go with it, but also of his entitlement to it. The ascetic, sober style imitates the sobriety and endurance of a successful general, even thought the clothing is that of a statesman rather than a general.\n",
"The portrait's facial features are consistent with those on coins struck in Caesar's last year, particularly on the denarii issued by Marcus Mettius. The bust's head is prolonged, forming a saddle shape which was caused by Caesar's premature ossification of the sutures between the parietal bone and the temporal bone. The portrait also exhibits dolichocephalia. According to several scholars, the Tusculum portrait is the only extant portrait of Caesar made during his lifetime.\n",
"and at Porta Salaria. The busts to be found today in the Albertoni Spinola palace are \"two ancient marble heads – one of a young woman and one of Antinous – mended in part; another ancient marble head – a priest of Isis – reworked in the Renaissance era as a portrait of Publius Cornelius Scipio Africanus; two marble portraits reconstructed during the Renaissance era – one of Julius Caesar and another probably of Hesiod or Zeno of Elea – and a plaster cast of the head of Julius Caesar (probably of the Pacca and not of the Paluzzi family) taken from the statue preserved in the Senatorial Palace on the Capitoline Hill\n",
"During the time of Napoleon Bonaparte, it was customary to cast a death mask of a great leader who had recently died. A mixture of wax or plaster was carefully placed over Napoleon's face and removed after the form had hardened. From this impression, subsequent copies were cast. Much mystery and controversy surrounds the origins and whereabouts of the most original cast moulds. There are only four genuine bronze death masks known to exist.\n",
"Togatus Barberini is a Roman marble sculpture from around the first-century AD that depicts a full-body figure, referred to as a \"togatus\", holding the heads of deceased ancestors in either hand. It is housed in the Centrale Montemartini in Rome, Italy (formerly in the Capitoline Museums). Little is known about this sculpture and who it depicts, but it is speculated to be a representation of the Roman funerary practice of creating death masks.\n",
"Speculation that the bust was meant to portray Lucius Junius Brutus of antiquity began with the writings of the 16th-century Italian naturalist Ulisse Aldrovandi. The Dutch 17th-century antiquary and editor of Lactantius Gallaeus Servatius alleged that a Roman coin minted during the consulship of Brutus bore similar facial features to the bust. The profile of the bust is similar to the profile on a coin, depicting Lucius Junius Brutus, minted by Marcus Junius Brutus following the assassination of Julius Caesar.\n"
] |
Is it possible that our solar system is inside of the event horizon of a black hole? | This write up seems to refute the idea - [relevant post by robot roll call](_URL_0_) | [
"An observer crossing the event horizon of a non-rotating and uncharged (or Schwarzschild) black hole cannot avoid the central singularity, which lies in the future world line of everything within the horizon. Thus one cannot avoid spaghettification by the tidal forces of the central singularity.\n",
"In the simple picture of stellar collapse leading to formation of a black hole, an event horizon forms before an apparent horizon. As the black hole settles down, the two horizons approach each other, and asymptotically become the same surface. If the AH exists, it is necessarily inside of the EH.\n",
"The location of the event horizon is determined by the larger root of formula_58. When formula_59 (i.e. formula_60), there are no (real valued) solutions to this equation, and there is no event horizon. With no event horizons to hide it from the rest of the universe, the black hole ceases to be a black hole and will instead be a naked singularity.\n",
"The black hole event horizon is teleological in nature, meaning that we need to know the entire future space-time of the universe to determine the current location of the horizon, which is essentially impossible. Because of the purely theoretical nature of the event horizon boundary, the traveling object does not necessarily experience strange effects and does, in fact, pass through the calculatory boundary in a finite amount of proper time.\n",
"The event horizon of a black hole may be thought of as a surface moving outward at the local speed of light and is just on the edge between escaping and falling back. The event horizon of a white hole is a surface moving inward at the local speed of light and is just on the edge between being swept outward and succeeding in reaching the center. They are two different kinds of horizons—the horizon of a white hole is like the horizon of a black hole turned inside-out.\n",
"Another hypothesis by astronomers A. G. W. Cameron and R. Stothers states that the companion of Epsilon Aurigae A is a black hole, consuming solid particles from the dusk cloud that bypass its event horizon which sends out the infrared light detected from Earth. This hypothesis has since been regarded obsolete and discarded.\n",
"BULLET::::- Event horizon - the boundary separating a black hole from the rest of the universe. Anything crossing the event horizon into the black hole cannot ever come back, since nothing can ever cross the event horizon from the other direction.\n"
] |
If you pour equal amounts of hot and cold water in a container, would the resulting mixture be the exact median of the two temperatures? | In good approximation yes, as the total energy is conserved and the temperature is a direct measure of energy per volume. The mixture will have the average energy per volume of the two initial portions and therefore the same temperature.
However the factor of proportionality between temperature and energy itself is also slightly temperature dependent (as shown [here](_URL_0_)), so that this will be only true in first approximation.
Calculating the final temperature taking this into account will be slightly more complicated and requires you to invert the polynomial relation between heat and temperature.
As you can see heat capacity greatly increases when you come close to freezing/boiling temperatures. This is because at these temperatures energy that you transfer into the system will not only affect the average movement/vibrations of a the water-molecules, but will also be used to change the state of aggregation. Ice at zero degrees has a very different energy content than water at zero degrees. | [
"Mixtures with 3–5 °C span of temperatures and ranges from about 17–23°C to about 37–40 °C can be composed from varying proportions of cholesteryl oleyl carbonate, cholesteryl nonanoate, and cholesteryl benzoate. For example, the mass ratio of 65:25:10 yields range of 17–23 °C, and 30:60:10 yields range of 37–40 °C.\n",
"Equal mixtures of liquid and below will separate into two immiscible phases due to their dissimilarity (they follow different quantum statistics: atoms are bosons while atoms are fermions). Dilution refrigerators take advantage of the immiscibility of these two isotopes to achieve temperatures of a few millikelvins.\n",
"The upper critical solution temperature (UCST) or upper consolute temperature is the critical temperature above which the components of a mixture are miscible in all proportions. The word \"upper\" indicates that the UCST is an upper bound to a temperature range of partial miscibility, or miscibility for certain compositions only. For example, hexane-nitrobenzene mixtures have a UCST of 19 °C, so that these two substances are miscible in all proportions above 19 °C but not at lower temperatures. Examples at higher temperatures are the aniline-water system at 168 °C (at pressures high enough for liquid water to exist at that temperature), and the lead-zinc system at 798 °C (a temperature where both metals are liquid).\n",
"As a liquid is supercooled, the difference in entropy between the liquid and solid phase decreases. By extrapolating the heat capacity of the supercooled liquid below its glass transition temperature, it is possible to calculate the temperature at which the difference in entropies becomes zero. This temperature has been named the Kauzmann temperature.\n",
"When either of the gases are mixed in excess of this ratio, or when mixed with an inert gas like nitrogen, the heat must spread throughout a greater quantity of matter and the temperature will be lower.\n",
"These two curves necessarily meet where the mixture becomes purely one component, namely where (and , pure component 2) or (and , pure component 1). The temperatures at those two points correspond to the boiling points of each of the two pure components.\n",
"The hot fluid heats the cold one, and the cold fluid cools down the warm one. The result is thermal equilibrium: Both fluids end up at around the same temperature: 40 °C, almost exactly between the two original temperatures (20 and 60 °C). At the input end, there is a large temperature difference of 40 °C and much heat transfer; at the output end, there is a very small temperature difference (both are at the same temperature of 40 °C or close to it), and very little heat transfer if any at all. If the equilibrium—where both tubes are at the same temperature—is reached before the exit of the liquid from the tubes, no further heat transfer will be achieved along the remaining length of the tubes.\n"
] |
how do we know that my blue is your blue? | We aren't. This holds true for all "fundamentals" in human perception - sound, taste, etc. | [
"BULLET::::- Dictionary (also voiced by Brianna Gentilella) - A book containing many words and their definitions that Blue looks in almost every day to find out what the Word of the Day is. She has a face and has the ability to speak, similar to all other residents of Blue's Room.\n",
"Blue is a primary color. It is the color of the ocean and the sky; it often symbolizes serenity, stability, or inspiration. It can be a calming color, and symbolize reliability. In the Catholic Church, the Virgin Mary is most often depicted wearing blue, to symbolize being \"full of grace\" by divine favor. Blue is widely used for baby boys' clothes or bedrooms, although the reason blue is so strongly associated with boys is debated.\n",
"BULLET::::- Blue stands for peace, tranquility, calm, stability, harmony, unity, trust, truth, confidence, conservatism, security, cleanliness, order, loyalty, sky, water, and technology. It is the color of trust and peace. It can suggest loyalty and integrity.\n",
"The Gemara used the account of to help explain the blue in the fringes (, \"tzitzit\") of the prayer shawl (, \"tallit\"). It was taught in a Baraita that Rabbi Meir used to ask why specified blue from among all the colors for the fringes. Rabbi Meir taught that it was because blue resembles the color of the sea, and the sea resembles the color of the sky, and the sky resembles the color of the Throne of Glory, as says, \"And there was under His feet as it were a paved work of sapphire stone,\" and says, \"The likeness of a throne as the appearance of a sapphire stone.\" (And thus, when one sees the blue thread of the fringe, it will help call to mind God.) And it was taught in a Baraita that Rabbi Meir used to say that the punishment for failing to observe the white threads of the fringes is greater than for failing to observe the blue threads. The Gemara illustrated this by a parable: A king gave orders to two servants. He asked one servant to bring a seal of clay, and he asked other to bring a seal of gold. And they both failed in their tasks. The Gemara argued that the servant deserving the greater punishment was the one whom the king directed to bring a seal of clay. (For clay is easier to get than gold. Thus the punishment for failing to get the simple white fringe should be greater than the penalty for failing to get the rare blue thread.)\n",
"According to Gary Waldman, \"A careful reading of Newton's work indicates that the color he called indigo, we would normally call blue; his blue is then what we would name blue-green, cyan or light blue.\" If this is true, Newton's seven spectral colors would have been:\n",
"The ancient term for blue (γλαυκός) has disappeared from Modern Greek as such, replaced by γαλάζιο (\"galázio\") or θαλασσί (\"thalassí\", “sea colored”) for light blue / sea blue, and the recent loan-word μπλε (\"ble\", from French \"bleu\")(μπ = \"b\") is used for blue.\n",
"The song's lyrics tell a story about a man who lives in a \"blue world.\" It is also stated he is \"blue inside and outside,\" which, along with the lyric \"himself and everybody around 'cause he ain't got nobody to listen,\" and \"blue are the feelings that live inside me\" may indicate that the term \"blue\" represents his emotional state; however, the song also states that a vast variety of what he owns is also blue, including his house and his car (\"a blue Corvette\"): various blue-coloured objects are also depicted on the single's cover. The song's hook is the sentence \"I'm blue,\" followed by a repetition of the sounds \"da ba dee da ba daa\", which the hook is based around. This sound shared by related compositions such as \"Around the World (La La La La La)\" by ATC that surfaced around the same time.\n"
] |
how does overheating affect a laptop's performance? | Excessive heat can damage the silicon logic or the metal wires or capacitor's electrolytes or melt insulation. It can set fire to dust inside the machine. | [
"Due to the relatively small size that the hardware has to fit in, cooling the heat intensive components is a major problem affecting the performance of such laptops, usually causing degraded value for money performance wise. Attempts at using the same performance hardware as desktops usually end in a decreased clock frequency of graphics chips to reduce heat, causing the poor value for money.\n",
"In 2003, Dell released several lines of Inspiron notebooks that had overheating issues. The systems would overheat and could cause damage to the microprocessor, video card, and motherboard. These systems would also randomly shut down due to high internal temperatures. Overheating in these Inspiron systems is mainly caused by performance-consuming tasks and software. This problem was determined to be due to the design of the air-flow from the bottom of the system. It would draw in dirt/dust and clog the heat sink, making air unable to pass through in order to cool the system. Affected models include the Dell Inspiron 1100, 1150, 5100, 5150, and 5160. Also affected is the Latitude 100L, a near-clone of these models.\n",
"In the past, some laptops have used a desktop processor instead of the laptop version and have had high performance gains at the cost of greater weight, heat, and limited battery life, but the practice was largely extinct as of 2013. Unlike their desktop counterparts, laptop CPUs are nearly impossible to overclock. A thermal operating mode of laptops is very close to its limits and there is almost no headroom for an overclocking–related operating temperature increase. The possibility of improving a cooling system of a laptop to allow overclocking is extremely difficult to implement.\n",
"Another advantage of the desktop is that (apart from environmental concerns) power consumption is not as critical as in laptop computers because the desktop is exclusively powered from the wall socket. Desktop computers also provide more space for cooling fans and vents to dissipate heat, allowing enthusiasts to overclock with less risk. The two large microprocessor manufacturers, Intel and AMD, have developed special CPUs for mobile computers (i.e. laptops) that consume less power and lower heat, but with lower performance levels.\n",
"Many computers and other devices allow for underclocking. Manufacturers add underclocking options for many reasons. Underclocking can help with excessive heat buildup, because lower performance will not generate as much heat inside the device. It can also lower the amount of energy needed to run the device. Laptop computers and other battery-operated devices often have underclocking settings, so that batteries can last longer without being charged.\n",
"These laptops are notorious for having an overheating problem. It's caused by the cooling fan having no filter and sucking up dust, debris and hair from dirty environments, clogging up its heat sinks and exhaust port, then accidentally blocking the fan intake vents until it overheats. Worse, the entire laptop must be completely disassembled and the motherboard entirely removed to access the area that gets clogged up. Regularly blasting compressed air into the exhaust port on the left rear side (below the VGA & expansion ports) while it's running will help, but if you typically see idle temps above 115-120 deg F you've got a problem and need to clean it out. Once apart and cleaned, placing a 2\" square piece of speaker grill fabric between the fan and the intake vents on the bottom of the chassis will alleviate the problem. After cleaning you should see 85-95F idle temps depending on processor.\n",
"Laptops rely on extremely compact cooling systems involving a fan and heat sink that can fail from blockage caused by accumulated airborne dust and debris. Most laptops do not have any type of removable dust collection filter over the air intake for these cooling systems, resulting in a system that gradually conducts more heat and noise as the years pass. In some cases the laptop starts to overheat even at idle load levels. This dust is usually stuck inside where the fan and heat sink meet, where it can not be removed by a casual cleaning and vacuuming. Most of the time, compressed air can dislodge the dust and debris but may not entirely remove it. After the device is turned on, the loose debris is reaccumulated into the cooling system by the fans. A complete disassembly is usually required to clean the laptop entirely. However, preventative maintenance such as regular cleaning of the heat sink via compressed air can prevent dust build up on the heat sink. Many laptops are difficult to disassemble by the average user and contain components that are sensitive to electrostatic discharge (ESD).\n"
] |
how do audio editors manage to dub movies without losing the rest of the sounds(i.e. ambient noises, background music, gunshot noises) | There are multiple soundtracks going on at the same time and each soundtrack can be adjusted individually. So they record the background noises, they record the voices and they record other things as well.
When they replace the voices, they just switch out the voice track but keep others the same or adjust them. | [
"The process usually takes place on a dub stage. After sound editors edit and prepare all the necessary tracks – dialogue, automated dialogue replacement (ADR), effects, Foley, music – the dubbing mixers proceed to balance all of the elements and record the finished soundtrack. Dubbing is sometimes confused with ADR, also known as \"additional dialogue replacement\", \"automated dialogue recording\" and \"looping\", in which the original actors re-record and synchronize audio segments.\n",
"During the \"final mix\" the re-recording/dubbing mixers, guided by the director or producer, must make creative decisions from moment to moment in each scene about how loud each major sound element (dialog, sound effects, laugh track and music) should be relative to each other. They also modify individual sounds when desired by adjusting their loudness and spectral content and by adding artificial reverberation. They can insert sounds into a three-dimensional space of the listening environment for a variety of venues and release formats: movie theaters, home theater systems, etc. that have stereo and multi-channel (5.1, 7.1, etc.) surround sound systems. Today, films may be mixed in 'object-based' audio formats such as Dolby Atmos, which introduces a heightened atmosphere within the sound field with the introduction of ceiling speakers and the elimination of audio channels.\n",
"Scenes where dialogue is replaced using dubbing also feature Foley sounds. Automatic dialogue replacement (ADR) is the process in which voice sounds are recorded in post production. This is done by a machine that runs the voice sounds with the film forward and backward to get the sound to run with the film. The objective of the ADR technique is to add sound effects into the film after filming, so the voice sounds are synchronized. Many sounds are not added at the time of filming, and microphones might not capture a sound the way the audience expects to hear it. The need for Foley rose dramatically when studios began to distribute films internationally, dubbed in other languages. As dialogue is replaced, all sound effects recorded at the time of the dialogue are lost as well.\n",
"A sound editor is a creative professional responsible for selecting and assembling sound recordings in preparation for the final sound mixing or mastering of a television program, motion picture, video game, or any production involving recorded or synthetic sound. Sound editing developed out of the need to fix the incomplete, undramatic, or technically inferior sound recordings of early talkies, and over the decades has become a respected filmmaking craft, with sound editors implementing the aesthetic goals of motion picture sound design.\n",
"Dubbing is commonly used in science fiction television, as well. Sound generated by effects equipment such as animatronic puppets or by actors' movements on elaborate multi-level plywood sets (for example, starship bridges or other command centers) will quite often make the original character dialogue unusable. \"Stargate\" and \"Farscape\" are two prime examples where ADR is used heavily to produce usable audio.\n",
"In the traditional subtitling countries, dubbing is generally regarded as something strange and unnatural and is only used for animated films and TV programs intended for pre-school children. As animated films are \"dubbed\" even in their original language and ambient noise and effects are usually recorded on a separate sound track, dubbing a low quality production into a second language produces little or no noticeable effect on the viewing experience. In dubbed live-action television or film, however, viewers are often distracted by the fact that the audio does not match the actors' lip movements. Furthermore, the dubbed voices may seem detached, inappropriate for the character, or overly expressive, and some ambient sounds may not be transferred to the dubbed track, creating a less enjoyable viewing experience.\n",
"Sound-effects editors typically use an organized catalog of sound recordings from which sound effects can be easily accessed and used in film soundtracks. There are several commercially distributed sound-effects libraries available, the two most well-known publishers being Sound Ideas and The Hollywood Edge. Online search engines, such as Sounddogs, A Sound Effect and Sonniss allow users to purchase sound effects libraries from a large online database.\n"
] |
how can we so distinctly remember things that never actually happened? | It is possible to vividly imagine something and then simply re-categorize that mental image as a memory rather than something you imagined. The act of remembering it works just the same. You can see what it looks like, hear the sounds or voices, and so forth. You just have attached a wrong category to it. | [
"There is barely any recalled memory in cases of fear and trauma exposure, brain injury, post-traumatic stress disorder, pain, or anxiety. Recall memory is very limited, since the only memory people have that suffer from these problems is the flash backs of what happened when the event took place. People can only recall the memory that happened on that day when they hear or see something that brings the memory into existence. They cannot recall how they felt or what they saw, but through images or audio people can recall that tragic event. For example, the day of September 11, 2001, first responders remember the day and what it was like; but the feelings they could not recall. The only way to recall the feelings they had were when sirens of police vehicles, fire trucks, and ambulances drove by their house they feel the exact feelings that were in effect on that day. \n",
"\"That's always baffled me,\" he said In a slow and measured tempo. \"There doesn't seem to be any consistency in the importance of what is remembered. One recalls a shadow on a wall, a gesture, something of no great importance, remembers it for years--and then forgets some extremely important fact like the address of one of the underground photographic laboratories. I suppose only a student of memory could give you the answer and then I wouldn't be particularly impressed. Memory is like a hot coal-it fades and grows bright again and fades.\"\n",
"When remembering things from one's past, it is easier to remember events that are tied to a major life-changing event (e.g. flashbulb memories. Research done by Norman Brown, Peter Lee, and others, tested the hypothesis that memory is organized based on life-changing events by having participants recall memories with historically defined autobiographical periods (H-DAPs; i.e. \"during the war\", \"after the earthquake\"). The results found that participants that lived in war zones or places where a natural disaster such as a tsunami had occurred typically would refer to their H-DAPs to date personal events, while New Yorkers almost never mentioned the attacks of 9/11. The researchers believed this was happening because even though they remembered the attacks of 9/11, they had very little direct effect on their everyday lives. They concluded that people use historical events to date their memories; however, what events they use and how they choose to use them remains to be determined.\n",
"Suddendorf and Busby have also specifically criticized the term episodic-like memory and believe it should be called www-memory (what-where-when memory) instead. They argued that an animal could know what happened, where it happened, and when it happened without actually being able to remember the specific event. Likewise, personal memories are not always accurate. Therefore, remembering a personal past event does not necessarily involve remembering the when and the where of the past event.\n",
"The minutest incidents of childhood, or forgotten scenes of later years, were often revived: I could not be said to recollect them; for if I had been told of them when waking, I should not have been able to acknowledge them as parts of my past experience. But placed as they were before me, in dreams like intuitions, and clothed in all their evanescent circumstances and accompanying feelings, I recognized them instantaneously […] I feel assured that there is no such thing as forgetting possible to the mind.\n",
"Dozens of people from all across the United States suddenly find themselves recalling random things: song lyrics, places, and events that seem to have been erased from both collective memory and recorded history. Fearing the spread of a virus-like plague, a mysterious group known as “The Handlers” is tasked with hunting and destroying those who recollect. But, does the end justify the means? And what if you were the one whose mind was unwittingly filled with things you shouldn’t remember? Things You Shouldn’t Remember serves up a cocktail of adventure, horror, and humor in a story that will keep you guessing… and make you wonder if your own memories should be trusted.\n",
"In the 1980s, a major theme in Jacoby's work was that the feeling of remembering does not inhere in the use of memory traces. As he noted, one can use memory records of specific past episodes without having a subjective feeling of remembering (as in involuntary plagiarism) and one can have a subjective feeling of remembering without there being any directly corresponding prior episode and hence no directly corresponding memory trace (as in false-memory phenomena). Jacoby argued that the feeling of remembering arises when a person infers (usually very quickly and without conscious reflection) that current thoughts and images are based on memories of a prior episode – that is, when people attribute current mental events to the past. For a beautifully written and compelling synthesis of Jacoby's work on this perspective, see his 1989 chapter with Colleen Kelley and Jane Dywan in a book in honour of Endel Tulving coedited by Roediger and Craik. In his work with Kelley, he made a distinction between memory that influences performance (he called it \"memory as a tool\"), which is implicit or unconscious memory outside our awareness, and recollection memory (he called it \"memory as an object\"), which is conscious memory of an event.\n"
] |
how to simplify square roots, such as √99 into 3√11? i just can't understand this concept. | okay! so basically you divide while it's still inside the square root. so √99 = √(9•11)=(√9)•(√11). √9=3. so √99=3•√11=3√11. | [
"Indeed, an early method for calculating square roots can be found in some Sutras, the method involves the recursive formula: formula_11 for large values of x, which bases itself on the non-recursive identity formula_12 for values of \"r\" extremely small relative to \"a\".\n",
"In order to determine the right sign of the square roots, one simply chooses some square root for each of the numbers , , and and uses them to compute the numbers , , , and from the previous equalities. Then, one computes the number . Note that, since , , and are the roots of (\"), it is a consequence of Vieta's formulas that their product is equal to and therefore that . But a straightforward computation shows that\n",
"A completely different method for computing the square root is based on the CORDIC algorithm, which uses only very simple operations (addition, subtraction, with bitshift and table lookup to implement multiplication). The square root of \"S\" may be obtained as the output formula_214 using the hyperbolic coordinate system in vectoring mode, with the following initialization:\n",
"The square root of 2, or the (1/2)th power of 2, written in mathematics as or , is the positive algebraic number that, when multiplied by itself, gives the number 2. Technically, it is called the principal square root of 2, to distinguish it from the negative number with the same property.\n",
"In mathematics, a square root of a number \"a\" is a number \"y\" such that ; in other words, a number \"y\" whose \"square\" (the result of multiplying the number by itself, or ) is \"a\". For example, 4 and −4 are square roots of 16 because .\n",
"A square root can be constructed with a compass and straightedge. In his Elements, Euclid (fl. 300 BC) gave the construction of the geometric mean of two quantities in two different places: Proposition II.14 and Proposition VI.13. Since the geometric mean of \"a\" and \"b\" is , one can construct simply by taking .\n",
"The square root of 2, often known as root 2, radical 2, or Pythagoras' constant, and written as , is the positive algebraic number that, when multiplied by itself, gives the number 2. It is more precisely called the principal square root of 2, to distinguish it from the negative number with the same property.\n"
] |
Can you break your own teeth by closing your jaw? | If your teeth are damaged from tooth decay you most certainly can.
The teeth are made of calcium and if they aren't taken care of they can slowly get eaten away by bacteria on the teeth. This will weaken the surrounding layer of the tooth and eventually make them brittle and prone to damage.
Even if your teeth aren't damaged from tooth decay they can still get damage from grinding your teeth. People tend to do this in their sleep or if they are nervous. What happens is a person will unconsciously or consciously bite down and move their jaw from side to side. This causes the teeth to slowly grind down through one another like rubbing two stones together. | [
"The mouth is unique, in that the teeth are well secured to the bone ends but come through epithelium (mucosa). A leg or wrist, for instance, has no such structure to help with a closed reduction. In addition, when the fracture happens to be in a tooth bearing area of the jaws, aligning the teeth well usually results in alignment of the fracture segments.\n",
"When a person has a dislocated jaw it is difficult to open and close the mouth. Dislocation can occur following a series of events if the jaw locks while open or unable to close. If the jaw is dislocated, it may cause an extreme headache or inability to concentrate. When the muscle's alignment is out of sync, a pain will occur due to unwanted rotation of the jaw.\n",
"In contrast, symptoms of a fractured jaw include bleeding coming from the mouth, unable to open the mouth wide without pain, bruising and swelling of the face, difficulty eating due to the constant pain, loss of feeling in the face (more specifically the lower lip) and lacks full range of motion of the jaw.\n",
"Mandibular fracture, also known as fracture of the jaw, is a break through the mandibular bone. In about 60% of cases the break occurs in two places. It may result in a decreased ability to fully open the mouth. Often the teeth will not feel properly aligned or there may be bleeding of the gums. Mandibular fractures occur most commonly among males in their 30s.\n",
"BULLET::::- Damage to the PDL may result in tooth ankylosis to the jawbone, making the tooth lose its continuous eruption ability. Dental trauma, such as subluxation, may cause tearing of the PDL and pain during function (eating).\n",
"BULLET::::- Snake jaws cannot unhinge. The posterior end of the lower jaw bones contain a quadrate bone, allowing jaw extension. The anterior tips of the lower jaw bones are joined by a flexible ligament allowing them to bow outwards, increasing the mouth gape.\n",
"In 2014, Liliana Cernecca, a six-year-old girl at the time, was only able to open her mouth a couple millimeters after one of her jaw joints fused. She underwent surgery to correct her jaw ankylosis during which her jaw was operated on and unlocked.\n"
] |
. how do soda fountain machines work? | Lots of tubes, and a mixer on each nozzle.
Basically there are 3 parts that go into your fountain soda.
Water - first tube from water supply to each nozzle.
Co2 - large canister in back (think like size of a large helium tank) - 2nd tube to each nozzle.
Syrup - generally come in boxes. Heavy plastic bag inside box with about 3 gal of syrup - 3rd tube to each nozzle.
Nozzles contain a mixer mechanism - basically can control hoe much of each of the 3 to dispense. (ie 1 part syrup to 1 part CO2 to 4 parts water.)
The carbonated water and syrup spray into the funnel part of the nozzle and into your cup. If the funnel part were removed, the carbonated water and syrup would be seen coming out as 2 separate streams.
If you ever see a Coke nozzle dispensing only carbonated water - the syrup box is empty and needs to be changed out (takes about a minute)
If your soda is totally flat, time to switch Co2 canisters.
If your soda is too bubbly and not enough flavor - time to recalibrate the dispenser quantities. | [
"A soda fountain is a device that dispenses carbonated soft drinks, called fountain drinks. They can be found in restaurants, concession stands and other locations such as convenience stores. The device combines flavored syrup or syrup concentrate and carbon dioxide with chilled and purified water to make soft drinks, either manually, or in a vending machine which is essentially an automated soda fountain that is operated using a soda gun. Today, the syrup often is pumped from a special container called a bag-in-box (BiB).\n",
"In many modern restaurants and drinking establishments, soda water is manufactured on-site using devices known as carbonators. Carbonators use mechanical pumps to pump water into a pressurized chamber where it is combined with from pressurized tanks at approximately . The pressurized, carbonated water then flows to taps or to mixing heads where it is then mixed with flavorings as it is dispensed.\n",
"The back-end of an FCB machine is very similar to a regular soda fountain. Concentrated flavor syrups are mixed with filtered water, then carbonated. This mixture is then injected into a cylinder surrounded by freezer coils. The mixture freezes to the wall of the cylinder, then is scraped off by a rotating dasher, which also keeps the mixture uniformly mixed. FCB machines will often freeze to a temperature well below the freezing point of water, but the combination of pressure (up to 40 p.s.i.), sugar, the carbon dioxide mixture (carbonic acid freezes at -80 °C), and the constant stirring prevent the mass from freezing solid.\n",
"Performed using an even number of props greater than or equal to four, the fountain is a symmetrical pattern where each hand independently juggles exactly half the total number of props, i.e. each hand always throws to itself. As with the cascade, a fountain where the throws are to the outside of the catches is known as a reverse fountain (siteswap: 4). A fountain where only one hand juggles is generally known as an \"n in one hand\", where \"n\" is the number of props juggled. Unlike the cascade, fountains can be performed both synchronously (each hand throws at the same time) and asynchronously (hands throw alternately)\n",
"The fountain also has one other water feature: a hidden pipe with small nozzles was circled the fountain; by turning a key, the water could be turned on, drenching the spectators with fine jets of water.\n",
"The term \"soda jerk\" was a pun on \"soda clerk\", the formal job title of the drugstore assistants who operated soda fountains. It was inspired by the \"jerking\" action the server would use to swing the soda fountain handle back and forth when adding the soda water. The soda fountain spigot itself typically was a sturdy, shiny fixture on the end of a pipe or other similar structure protruding above the counter, curving towards where the glasses would be filled. All of the drinks were made with unflavored carbonated water. Consequently, the tap handle was large, as the soda jerker would use it frequently. This made the mixing of drinks a center of activity at the soda fountain.\n",
"The fountain is a juggling pattern that is the method most often used for juggling an even number of objects. In a fountain, each hand juggles separately, and the objects are not thrown between the hands, thus the number of balls is always even since any number of balls in one hand is doubled by the same number in the other hand. To illustrate this, it can be seen that in the most common fountain pattern where four balls are juggled, each hand juggles two balls independently. As Crego states \"In the fountain pattern, each hand throws balls straight up into the air and each ball is caught in the same hand that throws it.\"\n"
] |
Why does plasma create light, when it is just a superheated gas? | Everything emits [black-body radiation](_URL_6_), across a continuous spectrum of temperature which determines the distribution of emitted photons, "hot" things just emit significantly in our visual range.
Separate from that, when atoms or molecules transition from a higher to a lower energy state, [they emit specific frequencies](_URL_4_), forming "bands" rather than a smooth spectrum, which is how [spectroscopy](_URL_5_) can determine the composition of an object.
Generally a plasma, as with a candle flame, is hot enough to emit light both ways. There are "cold" or ["non-thermal" plasmas](_URL_1_) in which the electron gas is thousands of kelvin, but the atoms are at room temperature, and so not visible from black-body radiation, and can be invisible. It can also be too hot to be visible. In [this image](_URL_0_) from [_URL_2_](https://www._URL_2_/mag/2/18):
> the brightest areas of the photo are in fact the coolest. At 150 million °C (the temperature in the centre), the plasma doesn't emit in the spectrum of visible light.
| [
"Plasma techniques are especially useful because they can deposit ultra thin (a few nm), adherent, conformal coatings. Glow discharge plasma is created by filling a vacuum with a low-pressure gas (ex. argon, ammonia, or oxygen). The gas is then excited using microwaves or current which ionizes it. The ionized gas is then thrown onto a surface at a high velocity where the energy produced physically and chemically changes the surface. After the changes occur, the ionized plasma gas is able to react with the surface to make it ready for protein adhesion. However, the surfaces may lose mechanical strength or other inherent properties because of the high amounts of energy.\n",
"Plasma lamps are a family of light sources that generate light by exciting a plasma inside a closed transparent burner or bulb using radio frequency (RF) power. Typically, such lamps use a noble gas or a mixture of these gases and additional materials such as metal halides, sodium, mercury or sulfur. A waveguide is used to constrain and focus the electrical field into the plasma. In operation the gas is ionized and free electrons, accelerated by the electrical field, collide with gas and metal atoms. Some electrons circling around the gas and metal atoms are excited by these collisions, bringing them to a higher energy state. When the electron falls back to its original state, it emits a photon, resulting in visible light or ultraviolet radiation depending on the fill materials.\n",
"In plasma, gas atoms are excited to higher energy states and also ionized. As the atoms and molecules 'relax' to their normal, lower energy states they release a photon of light, this results in the characteristic “glow” or light associated with plasma. Different gases give different colors. For example, oxygen plasma emits a light blue color.\n",
"Plasma consists of a mixture of electrons, ions, radicals, neutrals and photons. Some of these species are in local thermodynamic equilibrium, while others are not. Even for simple gases like argon this mixture can be complex. For plasmas of organic monomers, the complexity can rapidly increase as some components of the plasma fragment, while others interact and form larger species. Glow discharge is a technique in polymerization which forms free electrons which gain energy from an electric field, and then lose energy through collisions with neutral molecules in the gas phase. This leads to many chemically reactive species, which then lead to a plasma polymerization reaction. The electric discharge process for plasma polymerization is the “low-temperature plasma” method, because higher temperatures cause degradation. These plasmas are formed by a direct current, alternating current or radio frequency generator.\n",
"Modern plasma lamps are a family of light sources that generate light by exciting plasma inside a closed transparent burner or bulb using radio frequency (RF) power. Typically, such lamps use a noble gas or a mixture of these gases and additional materials such as metal halides, sodium, mercury or sulfur. In modern plasma lamps, a waveguide is used to constrain and focus the electrical field into the plasma. In operation, the gas is ionized, and free electrons, accelerated by the electrical field, collide with gas and metal atoms. Some atomic electrons circling around the gas and metal atoms are excited by these collisions, bringing them to a higher energy state. When the electron falls back to its original state, it emits a photon, resulting in visible light or ultraviolet radiation, depending on the fill materials.\n",
"The source gas for the plasma usually contains small molecules rich in chlorine or fluorine. For instance, carbon tetrachloride () etches silicon and aluminium, and trifluoromethane etches silicon dioxide and silicon nitride. A plasma containing oxygen is used to oxidize (\"ash\") photoresist and facilitate its removal.\n",
"The source gas for the plasma usually contains small molecules rich in chlorine or fluorine. For instance, carbon tetrachloride (CCl) etches silicon and aluminium, and trifluoromethane etches silicon dioxide and silicon nitride. A plasma containing oxygen is used to oxidize (\"ash\") photoresist and facilitate its removal.\n"
] |
what was so major about that debate yesterday? | I got majorly drunk playing the Debate Drinking Game...
It's not really that major. It's just a tool the Republican Party uses to gauge which candidates are least likely to be eaten alive in the public eye. | [
"As the day before the debate, November 13, was the day of the November 2015 Paris attacks, CBS announced that the debate would focus on foreign policy and terrorism. In addition, a moment of silence was held at the beginning of the debate in memory of the victims.\n",
"The debate started in 1999 with an exchange of letters in Scientific American between Walter L. Wagner, and F. Wilczek, Institute for Advanced Study, in response to a previous article by M. Mukerjee. The media attention unfolded with an article in U.K. Sunday Times of July 18, 1999 by J. Leake, closely followed by articles in the U.S. media. The controversy mostly ended with the report of a committee convened by the director of Brookhaven National Laboratory, J. H. Marburger, ostensibly ruling out the catastrophic scenarios depicted. However, the report left open the possibility that relativistic cosmic ray impact products might behave differently while transiting earth compared to \"at rest\" RHIC products; and the possibility that the qualitative difference between high-E proton collisions with earth or the moon might be different than gold on gold collisions at the RHIC. Wagner tried subsequently to stop full energy collision at RHIC by filing Federal lawsuits in San Francisco and New York City, but without success. The New York suit was dismissed on the technicality that the San Francisco suit was the preferred forum. The San Francisco suit was dismissed, but with leave to refile if additional information was developed and presented to the court.\n",
"The debate was carried out from 2001 to 2003 through a series of published articles and open letters. It began with a 2001 article by Smalley in \"Scientific American\", which was followed by a rebuttal published by Drexler and coworkers later that year, and two open letters by Drexler in early 2003. The debate was concluded in late 2003 in a \"Point–Counterpoint\" feature in \"Chemical & Engineering News\" in which both parties participated.\n",
"The fourth debate was held on November 10, 2015, at the Milwaukee Theatre in Milwaukee, Wisconsin, airing on the Fox Business Network and sponsored by \"The Wall Street Journal\". This debate focused on jobs, taxes, and the general health of the U.S. economy, as well as on domestic and international policy issues. The moderators were Neil Cavuto, Maria Bartiromo and Gerard Baker.\n",
"Debategate involved the final days of the 1980 presidential election and briefing papers that were to have been used by President Jimmy Carter in preparation for the October 28, 1980, debate with Reagan had somehow been acquired by Reagan's team. This fact was not divulged to the public until late June 1983, after Laurence Barrett published \"\", an in-depth account of the Reagan administration's first two years.\n",
"The second presidential debate was held on October 15 in Richmond, Virginia, and included questions from undecided voters, who kept the candidates focused on the issues. During his opening statement, Perot explained that there was a \"giant sucking sound\" caused by the rush of manufacturing jobs to Mexico. During one exchange, Perot commented that Democrats and Republicans were both to blame for the deficit, but that neither was willing to take responsibility. He joked \"somewhere out there, there's an extraterrestrial that's doing this to us, I guess.\" At the close of the debate, Perot described himself as \"results ... [and] action oriented\", and explained that \"if they want to keep slow dancing and talk about it and not do it, I'm not your man.\" Perot took part in the third debate held in East Lansing, Michigan, on October 19. Throughout the debate, he plugged and referenced his infomercials. He criticized Bush's economic plan to start off the debate, stating that it would not balance the budget. He later remarked that he would spend $60 million of his own money to finish the race. Notably, Perot brought up the fact that \"both parties have foreign lobbyists on leaves and key roles in the campaigns.\" After the debate, he ripped the media during a press conference, criticizing them for their use of \"gotcha\" stories and the lack of coverage concerning his opponent's foreign lobbyists. Former pollster Frank Luntz explained, \"When Ross Perot uses his head, he's unbeatable. He's focused, straightforward and compelling. When he uses his heart, sometimes his emotions get carried away.\"\n",
"The first debate took place on Monday, September 26, at New York's Hofstra University, moderated by Lester Holt of NBC. It was originally scheduled to take place at Wright State University, but the venue was changed due to security and financial concerns.\n"
] |
Why do people experience cravings years after they have quit the substance to which they were addicted? | You should think about addiction as a *learned* behavioural response. Cravings are usually triggered by two events, first is when exposed to drug related stimuli (e.g. seeing a crackpipe, bong, watching people take drugs, walking past the pub, thinking about drug use) and the second is when exposed to stressors.
In the first example, the person has previously *learned* to associate drug related cues to reward related internal processes. This is a natural learning process most likely mediated primarily by [classical conditioning](_URL_0_) and is the same kind of learning as when you associate a particular perfume smell to that old girl/boyfriend you used to date. So when exposed to drug related cues, you get that automatic association with reward pathways. And humans at their most basic are driven to obtain reward - hence cravings.
In the stress induced cravings, the person has previously *learned* that the use of drugs can reduce the negative feelings of stress and negative mood states. This learning process is mediated by [negative reinforcement](_URL_1_) learning. So in this sense, craving can be induced by a desire to reduce the negative feelings.
Based on this, it is important to note how difficult it is to unlearn something. So going back to the example of the perfume, the thoughts you have of the old girl/boyfriend are almost automatic. The learning is very strong. Same way as if you have a particular strategy (maybe it is having chocolate, or seeing a movie, or playing with your kids) for calming yourself down when you are angry, or increasing you mood when feeling down. Imagine taking that tried and tested strategy for reducing the negative mood. This is what cravings are all about. They are automatic responses to a strongly learned behavioural response. | [
"A variety of addictive drugs produce an increase in reward-related dopamine activity. Stimulants such as nicotine, cocaine and methamphetamine promote increased levels of dopamine which appear to be the primary factor in causing addiction. For other addictive drugs such as the opioid heroin, the increased levels of dopamine in the reward system may only play a minor role in addiction. When people addicted to stimulants go through withdrawal, they do not experience the physical suffering associated with alcohol withdrawal or withdrawal from opiates; instead they experience craving, an intense desire for the drug characterized by irritability, restlessness, and other arousal symptoms, brought about by psychological dependence.\n",
"In his book, \"Rational Recovery\", Trimpey calls the addict's addictive voice \"the bark of Beast\", \"the Beast\" being the desire for intoxication. He proposes that this is the sole reason why addicts continue their self-destructive ways. Furthermore, by recognizing any feeling, image, urge, etc. that supports drinking/using as \"Beast activity\", the compulsions will fall silent, and the person can eventually regain control over their life and never worry about relapses. Rather than making addiction a lifelong battle, it is much easier to say \"no\" to the addictive voice, than to give in. Moreover, this separation of the rational self from the relentless \"Beast\" will, Trimpey says, enable addicts to always remain aware of the repercussions associated with a single relapse.\n",
"Some claim the existence of “addictive beliefs” in people more likely to develop addictions, such as “I cannot make an impact on my world” or “I am not good enough”, which may lead to developing traits associated with addiction, such as depression and emotional insecurity. People who strongly believe that they control their own lives and are mostly self-reliant in learning information (rather than relying on others) are less likely to become addicted. However, it is unclear whether these traits are causes, results or merely associated coincidentally. For example, depression due to physical disease can cause feelings of hopelessness that are mitigated after successful treatment of the underlying condition, and addiction can increase dependence on others.\n",
"The duration that cravings last after discontinuation varies substantially between different addictive drugs. For instance, in smoking cessation, a substantial relief is achieved after approximately 6–12 months, but feelings of craving may temporarily appear even after many years following cessation.\n",
"There are some characteristics of addiction that regardless of the type share commonalities. The behavior provides a rapid and potent means of altering mood, thoughts, and sensations of a person which occur because of physiology and learned expectations. The immediate precipitating factors of the relapse, the timing of the relapse and the rate of relapse following treatment is high.\n",
"When an individual falls victim to drug addiction, they will undergo the five stages of addiction which are the first use, the continued use, tolerance, dependence, and addiction. The first use stage, is the stage where individuals experiment with drugs and alcohol. This is the stage where individuals will partake in drug use because of curiosity, peer pressure, emotional problems etc. They discover how the drug will make them feel. In the continued use stage, individuals know how the drug makes them feel and is likely to notice that they're not getting “high” as quickly as they use to. In the tolerance stage, the brain and the body have adjusted to the drug and it takes longer to get the “high” an individual is seeking. Tolerance arrives after a period of continued use and is one of the first warning signs of addiction. In the dependence stage, the brain becomes accustomed to the drug and doesn't function well without it. Substance abusers become physically ill without the use of drugs and will begin to develop symptoms of withdrawal. This is sign that the addiction is beginning to take hold of the individual. In the addiction stage, individuals find it impossible to stop using drugs even if they do not enjoy it or if their behavior has caused problems within an individual's life.\n",
"Cravings may be triggered by seeing objects or experiencing moments that are associated with the drug or usage of it, and this phenomenon, termed post acute withdrawal syndrome, may linger the rest of the life for some drugs. For the alcohol withdrawal syndrome, the condition gradually improves over a period of months or in severe cases years.\n"
] |
why is it that when my feet are cold and i put them under my covers, they start sweating but they're still freezing? | The control center in your brain for body temperature (the hypothalamus) is part of a different network than the sensory system for perception of heat (primary somatosensory cortex).
The control center for body temperature is more concerned about the temperature in your brain and other vital organs; so if your core is too warm, you will sweat all over. The will happen no matter how cold your feet are. Cold feet is less of a problem than a brain that is too hot. | [
"Wearing closed-toe shoes (\"e.g.\", ballet flats or pumps) without socks leads to accumulation of sweat, dead skin cells, dirt, and oils, further contributing to bacterial growth. Momentarily slipping off shoes whenever feet start to feel \"hot\" or sweaty can help prevent odor.\n",
"The main cause is foot sweat (also see focal hyperhidrosis). Sweat itself is odorless; however, it creates a beneficial environment for certain bacteria to grow, producing odorous substances. These bacteria are naturally present on our skin as part of the human flora. The front part of the foot produces the most sweat. \n",
"Excessive sweating or focal hyperhidrosis of the hands interferes with many routine activities, such as securely grasping objects. Some focal hyperhidrosis sufferers avoid situations where they will come into physical contact with others, such as greeting a person with a handshake. Hiding embarrassing sweat spots under the armpits limits the sufferers' arm movements and pose. In severe cases, shirts must be changed several times during the day and require additional showers both to remove sweat and control body odor issues or microbial problems such as acne, dandruff, or athlete's foot. Additionally, anxiety caused by self-consciousness to the sweating may aggravate the sweating. Excessive sweating of the feet makes it harder for patients to wear slide-on or open-toe shoes, as the feet slide around in the shoe because of sweat.\n",
"Sturdy and comfortable boots or shoes are essential because workers are on their feet much of the day. Hiking or safety boots are preferred because they protect feet from injury. Open-toed shoes or sandals are not allowed because bare feet can easily be injured. An extra pair of socks is beneficial when it rains or is cold. Gloves of two types are needed. First responders wear welder's gloves or Nomex gloves to protect their hands when pushing a hot car or removing a hot car part from the racing surface. Other workers may wear insulated gloves to protect their hands from the cold.\n",
"In some people, the body's mechanism for cooling itself is overactive—so overactive that they may sweat four or five times more than is typical. Millions of people are affected by this condition, but more than half never receive treatment due to embarrassment or lack of awareness. While it most commonly affects the armpits, feet, and hands, it is possible for someone to experience this condition over their whole body. The face is another common area for hyperhidrosis to be an issue. Sweating uncontrollably is not always expected and may be embarrassing to sufferers of the condition. It can cause both physiological and emotional problems in patients. It is generally an inherited problem that is found in each ethnic group. It is not life-threatening, but it is threatening to a person's quality of life.\n",
"The burning heat is usually limited to the soles of the feet, but may extend up to the ankles or lower legs of some patients. The burning can sometimes be accompanied by feelings of 'pins and needles' or tingling in these regions. Nighttime is when almost all sufferers of this syndrome report the heat symptoms being the worst, with the condition getting better as morning comes. Those who have psychosomatic disorders sometimes display psychological symptoms along with the burning of feet associated with the syndrome. For most, there is no redness of the skin of their feet during the heat sensations, and almost never is there accompanying tenderness along with it.\n",
"Sweating causes a decrease in core temperature through evaporative cooling at the skin surface. As high energy molecules evaporate from the skin, releasing energy absorbed from the body, the skin and superficial vessels decrease in temperature. Cooled venous blood then returns to the body's core and counteracts rising core temperatures.\n"
] |
why do some recent films from the 2000s need to go through a remaster process into higher resolutions like 4k? aren't the original source files already at their native resolution, especially if they were filmed digitally? | No, there was still a lot of film used in the 2000s. Even so, digitization for HD (1080) is very different from digitization for 4K (2160) because different bitrate limits are needed for the different formats. There might have been a 4K "digital" version for theaters with digital projectors in the 2000s, but that's not the right bitrate for an Ultra HD Bluray. | [
"In the spring of 2013, during its 86th year of existence, efforts began to convert to digital picture and sound (with the exception of productions that are only available in the movie reel format) and screened a free showing of \"Samsara\" to celebrate the transition. The switch to digital—in anticipation of an industry change whereby all new releases will only be available in digital format—occurred at a cost of $150,000.\n",
"It was announced in the summer of 2016 that the film was in the process of being digitally remastered to 4K quality for its 40th anniversary (which was reported to have begun before Bowie's death). This remastered version premiered at BFI Southbank before being released in cinemas across the UK on 9 September of that year.\n",
"Another concern with digital image capture is how to archive all the digital material. Archiving digital material is turning out to be extremely costly, and it creates issues in terms of long-term preservation. In a 2007 study, the Academy of Motion Picture Arts and Sciences found that the cost of storing 4K digital masters is \"enormously higher – 1100% higher – than the cost of storing film masters.\" Furthermore, digital archiving faces challenges due to the insufficient longevity of today's digital storage: no current media, be it magnetic hard drives or digital tape, can reliably store a film for a hundred years, something that properly stored and handled film can do. Although this also used to be the case with optical disc, in 2012 Millenniata, Inc. a digital storage company based in Utah, released M-DISC, an optical storage solution, designed to last up to 1,000 years, thus, offering a possibility of digital storage as a viable storage solution.\n",
"In 2002, Contender reissued the complete run on DVD (for the UK only). Although labelled as having been \"digitally remastered\", these releases have attracted some criticism, mainly due to the relatively poor picture quality (colour, contrast and levels of dirt and scratches). In part, this was due to problems with the age and condition of the prints used, and the loss of (or lack of access to) the original source footage which would normally be used as the basis of a remaster.\n",
"Due to the declining home video market for older and little-known films, most major film studios have opted to stop releasing those titles via conventional retail methods. Instead, studios like Warner Bros., Universal Studios, Sony Pictures, and MGM have gone the manufacture-on-demand (MOD) route, releasing these titles on DVD-R, often without any kind of restoration or remastering, or any kind of extras.\n",
"The film fell into the public domain and for years was only available via numerous low quality, budget reissues on VHS and DVD. In 2016, work was completed on a \"New 4K digital restoration, undertaken by Universal Pictures in partnership with The Film Foundation and in consultation with filmmakers Martin Scorsese and Steven Spielberg\". This restoration was issued on Blu-ray and DVD in November 2016 by the Criterion Collection in the US, and in June 2017 by Arrow Video in the UK.\n",
"Manufacturers continue to release standard DVD titles , and the format remains the preferred one for the release of older television programs and films. Shows that were shot and edited entirely on film, such as \"\", cannot be released in high definition without being re-scanned from the original film recordings. Certain special effects were also updated to appear better in high-definition. Shows that were made between the early '80s and the early 2000s were generally shot on film, then transferred to cassette tape, and then edited natively in either NTSC or PAL, making high-definition transfers literally impossible as these SD standards were baked into the final cuts of the episodes. \"\" is the only such show that has gotten a Blu-Ray release. The process of making high-definition versions of \"TNG\" episodes required finding the original film clips, re-scanning them into a computer at high definition, digitally re-editing the episodes from the ground up, and re-rendering new visual effects shots, an extraordinarily labor-intensive ordeal that cost Paramount over $12 million. The project was a financial failure and resulted in Paramount deciding very firmly against giving \"Deep Space Nine\" and \"Voyager\" the same treatment.\n"
] |
why does an extra oxygen atom make such a big difference between h2o (water) and h2o2 (rocket fuel)? | The bond between the two oxygen atoms in H2O2 is not very strong and, as a result, the molecule as a whole is rather unstable. H2O2 readily breaks down into normal H2O and O2, producing heat in the process. | [
"It just so happens that hydrogen (H) and oxygen (O) are both diatomic molecules, thus we have H and O. To form water, one of the O atoms breaks off from the O molecule and react with the H compound to form HO. But, there is one oxygen atom left. It reacts with another H molecule. Since it took two of each atom to balance the compound, we put the coefficient 2 in front of HO:\n",
"Because the ratio of hydrogen to oxygen atoms in all carbohydrates is always the same as that in water—that is, 2 to 1—all of the oxygen consumed by the cells is used to oxidize the carbon in the carbohydrate molecule to form carbon dioxide. Consequently, during the complete oxidation of a glucose molecule, six molecules of carbon dioxide and six molecules of water are produced and six molecules of oxygen are consumed.\n",
"Singlet oxygen is the common name used for the two metastable states of molecular oxygen (O) with higher energy than the ground state triplet oxygen. Because of the differences in their electron shells, singlet oxygen has different chemical and physical properties than triplet oxygen, including absorbing and emitting light at different wavelengths. It can be generated in a photosensitized process by energy transfer from dye molecules such as rose bengal, methylene blue or porphyrins, or by chemical processes such as spontaneous decomposition of hydrogen trioxide in water or the reaction of hydrogen peroxide with hypochlorite.\n",
"Triplet oxygen, \"\"O, refers to the \"S\" = 1 electronic ground state of molecular oxygen (dioxygen). It is the most stable and common allotrope of oxygen. Molecules of triplet oxygen contain two unpaired electrons, making triplet oxygen an unusual example of a stable and commonly encountered diradical. According to molecular orbital theory, the electron configuration of triplet oxygen has two electrons occupying two π molecular orbitals (MOs) of equal energy (that is, degenerate MOs). In accordance with Hund's rules, they remain unpaired and spin-parallel and account for the paramagnetism of molecular oxygen. These half-filled orbitals are antibonding in character, reducing the overall bond order of the molecule to 2 from a maximum value of 3 (e.g., dinitrogen), which occurs when these antibonding orbitals remain fully unoccupied. The molecular term symbol for triplet oxygen is Σ.\n",
"Oxygen can be partially hydrogenated to give hydrogen peroxide, although this process has not been commercialized. One difficulty is preventing the catalysts from triggering decomposition of the hydrogen peroxide to form water.\n",
"The rules state each oxygen is covalently bonded to two hydrogen atoms, and that the oxygen atom in each water molecule forms two hydrogen bonds with other oxygens, so that there is precisely one hydrogen between each pair of oxygen atoms.\n",
"Concurrently, the other oxygen atom is reduced to water. Even though molecular oxygen is the electron acceptor in these enzymes' reactions, they are unique because oxygen does not appear in the oxidized product.\n"
] |
The Fukang meteorite is estimated to be 4.5 billion years old, how is it that people manage to estimate its age? | The age of meteorites is measured the same way we measure the absolute age of materials on Earth, via [radiometric dating](_URL_0_). I'm going to venture a guess that your confusion might stem from a common misconception, namely that radiometric dating always equal carbon, or ^14 C, dating which is only useful over a few tens of thousand of years (and thus is not useful for measuring the age of meteorites or most geologic materials on Earth for that matter). In detail there are a whole host of useful radioactive isotopes that decay to stable products and that have half lives long enough to make them suitable for dating materials several billion years old. Specifically for meteorites, the most common radiometric systems are U-Pb, Sm-Nd, and Rb-Sr with half lives of 0.7 (for ^235 U - ^207 Pb), 4.5 (for ^238 U - ^208 Pb), 106, and 50 billion years, respectively (I've seen Ar-Ar dating used as well, which has a half life of 1.3 billion years, but usually in the context of dating an impact as opposed to the age of the meteorite itself). The useful range for any given isotope (i.e. the age of material you can date with it) is roughly between 1/10 to 10 times the half life, so all of these systems are useful for meteorites that formed at the same time as the rest of the solar system. Which radiometric system is used (and the details of how it is applied) will depend on they type of meteorite as these different radiometric systems only work with specific minerals as you need minerals which incorporate the radioactive parent into it's structure during crystallization and which retain the daughter isotope during decay. | [
"Less than ten thousand years old, and with a diameter of or more. The EID lists fewer than ten such craters, and the largest in the last 100,000 years (100 ka) is the Rio Cuarto crater in Argentina. However, there is some uncertainty regarding its origins and age, with some sources giving it as < 10 ka while the EID gives a broader 100 ka.\n",
"Žemaitkiemis meteorite is an ordinary chondrite that fell near Žemaitkiemis, Lithuania at about 8:33 pm on 2 February 1933. Using the argon–argon dating method, scientists have calculated its age to be about 520 million years. \n",
"On October 16, 2006, a related smaller meteorite measuring 154 pounds (70 kilograms) was dug up near Greensburg () and Haviland (). The only scientific publication discussing time of impact suggests a terrestrial age of 20,000 years. It was once thought that its age was closer to 10,000 years.\n",
"The craters' age is estimated as 4,000–5,000 years. The craters, containing iron masses, were reported in 1576, but were already well known to the aboriginal inhabitants of the area. The craters and the area around contain numerous fragments of an iron meteorite. The total weight of the pieces so far recovered is about 100 tonnes, making the meteorite possibly the heaviest one ever recovered on Earth.\n",
"Emi Koussi erupted between 2.4 and 1.3 million years ago; it is considered to be of Pliocene-Quaternary age. The volcano was constructed mainly during the Miocene within about one million years. Radiometric dating has yielded ages of 2.42 ± 0.03 - 2.33 ± 0.09 million years ago for the oldest Emi Koussi stage. The third stage has yielded ages of 1.4 ± 0.3 - 1.32 ± 0.2 million years ago; formerly Era Kohor was considered to be a Holocene centre.\n",
"The Fukang meteorite is a meteorite that was found in the mountains near Fukang, China in 2000. It is a pallasite—a type of stony–iron meteorite with olivine crystals. It is estimated to be 4.5 billion years old.\n",
"An age of 4.55 ± 0.07 billion years, very close to today's accepted age, was determined by Clair Cameron Patterson using uranium-lead isotope dating (specifically lead-lead dating) on several meteorites including the Canyon Diablo meteorite and published in 1956.\n"
] |
why is it illegal to copy the appearance/design of others' inventions, but not illegal to copy the taste of other brands' foods? | Appearance or design seems much more quantifiable than taste, which is far more subjective and varies from person to person. | [
"Some artists, such as Girl Talk and Nine Inch Nails, use copyleft licenses such as the Creative Commons Attribution-NonCommercial-ShareAlike license that don't allow commercial use. In this way they can choose to sell their creations without having to compete with others selling copies of the same works. However, some argue that the Attribution-NonCommercialShareAlike license is not a true copyleft.\n",
"Currently, fashion may only be protected by copyright to the extent that its shape is non-utilitarian enough to qualify as a creative \"sculpture,\" or to the extent that a design, pattern, or image on the clothing qualifies as \"pictorial\" or \"graphic.\" While current laws against counterfeit goods do provide some protection for designers, this is so only when the trademark is used and not when merely the design is copied under a different label. In addition, fashion may be protected by design patents if the requirements for patentability are met. To be patentable an ornamental design must be new, original and non-obvious. The United States Patent and Trademark Office website (www.uspto.gov) has a searchable database of patents, and includes patents on apparel in class D2, carrying articles in class D3, and eyeglass frames in class D16. Technological advances to the means of textile and garment production, as well as increases in the number of distribution channels and the availability of cheap labor in emerging economies have enabled those who would copy these designs to do so quickly and inexpensively. Legislation targeting design piracy has already been enacted in Europe, India, and Japan.\n",
"The copyright in a design document is not infringed by making or using articles to that design, unless the design is an artistic work or a typeface (s. 51). If an artistic work has been exploited with permission for the design by making articles by an industrial process and marketing them, the work may be copied by making or using articles of any description after the end of a period of twenty-five years from the end of the calendar year when such articles were first marketed (s. 52). It is not an infringement of the copyright in a typeface to use it in the ordinary course of printing or to use the material produced by such printing (s. 54).\n",
"Stanford Law professor Lawrence Lessig believes that for the first time in history creativity by default is subject to regulation because of two architectural features. First, cultural objects or products created digitally can be easily copied, and secondly, the default copyright law requires the permission of the owner. The result is that one needs the permission of the copyright owner to engage in mashups or acts of remixing. Lessig believes that the key to mashups and remix is \"education – not about framing or law – but rather what you can do with technology, and then the law will catch up\". \n",
"Any of the mentioned legal regimes may prohibit the distribution of the designs used in 3D printing, or the distribution or sale of the printed item. To be allowed to do these things, where an active intellectual property was involved, a person would have to contact the owner and ask for a licence, which may come with conditions and a price. However, many patent, design and copyright laws contain a standard limitation or exception for 'private', 'non-commercial' use of inventions, designs or works of art protected under intellectual property (IP). That standard limitation or exception may leave such private, non-commercial uses outside the scope of IP rights.\n",
"Although intellectual property laws such as these are theoretically distinct, more than one type may afford protection to the same article. For example, the particular design of a bottle may qualify for copyright protection as a non-utilitarian [sculpture], or for trademark protection based on its shape, or the 'trade dress' appearance of the bottle as a whole may be protectable. Titles and character names from books or movies may also be protectable as trademarks while the works from which they are drawn may qualify for copyright protection as a whole. Trademark protection does not apply to utilitarian features of a product such as the plastic interlocking studs on Lego bricks.\n",
"In the United States, the work is not required to be non-commercial in nature for copyright protection and unlike the US trademark law, the work need to be necessarily lawful. Therefore, works created for commercial purposes, such as advertisements can also be granted a copyright.\n"
] |
Why is it so difficult to clean up oil spills that happen in large bodies of water? | Actually, compared to other liquids, lipids can be removed quite easily as they are less dense than water and therefore float. When you pour oil into a tub of water, you can simply lay a tissue on the surface and it is going to absorb the oil quite neatly. I think for oil spills on the oceanic level the problems are that the sheer amount of oil is too enormous to be cleared easily. Also, animals will come into contact with it nevertheless (especially when the spill reaches the coast) and will cause the terrible problems that are associated with this. | [
"Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved. Physical cleanups of oil spills are also very expensive. However, microorganisms such as Fusobacteria species demonstrate an innovative potential for future oil spill cleanup because of their ability to colonize and degrade oil slicks on the sea surface.\n",
"Many oils can be recovered from open water surfaces by skimming devices. Considered a dependable and cheap way to remove oil, grease and other hydrocarbons from water, oil skimmers can sometimes achieve the desired level of water purity. At other times, skimming is also a cost-efficient method to remove most of the oil before using membrane filters and chemical processes. Skimmers will prevent filters from blinding prematurely and keep chemical costs down because there is less oil to process.\n",
"Major oil spills include, Lakeview Gusher, Gulf War oil spill, and the Deepwater Horizon oil spill. Spilt oil penetrates into the structure of the plumage of birds and the fur of mammals, reducing its insulating ability, and making them more vulnerable to temperature fluctuations and much less buoyant in the water. Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved. Other factors influencing the rate of long-term contamination is the continuous inputs of petroleum residues and the rate at which the environment can clean itself Spills may take weeks, months or even years to clean up.\n",
"Oil spills penetrate into the structure of the plumage of birds and the fur of mammals, reducing its insulating ability, and making them more vulnerable to temperature fluctuations and much less buoyant in the water. Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved. Spills may take weeks, months or even years to clean up.\n",
"Similar situations can be elucitated like in the case of oil spills in the oceans which require cleanup, microbes isolated from oil rich environments like oil wells, oil transfer pipelines...etc. have been found having the potential to degrade oil or use it as an energy source. Thus they serve as a remedy to oil spills.\n",
"Normally, many years are needed for an ecosystem to recover fully (if at all) from an oil spill, so scientists have been looking into ways to expedite the cleanup of areas affected by an oil spill. Most efforts so far use direct human involvement/labor to physically remove the oil from the environment. However, \"A. borkumensis\" presents a possible alternative. Since \"A. borkumensis\" naturally breaks down oil molecules to a nonpolluting state, it would help ecosystems to quickly recover from an oil spill disaster. The organisms also naturally grow in oil-contaminated seawater, thus are a native species. If the process \"A. borkumensis\" uses to break down oil could be sped up or made more efficient, this would aid recovering ecosystems. Some examples include encouraging the growth of \"A. borkumensis\" (through phosphorus and nitrogen fertilization) so more of them are breaking down oil, or encouraging the metabolism of \"A. borkumensis\" so they metabolize faster and more.\n",
"Oil spills at sea are generally much more damaging than those on land, since they can spread for hundreds of nautical miles in a thin oil slick which can cover beaches with a thin coating of oil. These can kill seabirds, mammals, shellfish and other organisms they coat. Oil spills on land are more readily containable if a makeshift earth dam can be rapidly bulldozed around the spill site before most of the oil escapes, and land animals can avoid the oil more easily.\n"
] |
Does the age in which you procreate affect what is inherited by the child? For example, will a child that is conceived by 20 year old parents have traits very different than if the parents were in their 50's? | I know Autism is linked to the age of the Father.
_URL_0_ | [
"The effects of the fathers age on offspring are not yet well understood and are studied far less extensively than the effects of the mother's age. Fathers contribute proportionally more DNA mutations to their offspring via their germ cells than the mother, with the paternal age governing how many mutations are passed on. This is because, as humans age, male germ cells acquire mutations at a much faster rate than female germ cells.\n",
"Father absence in a household can result in children (of both sexes) having earlier average ages of first sexual intercourse than those raised in father present households. There is also the effect of increased rates of teenage pregnancy. Some evolutionary theories propose that early childhood is vital for encoding information that shapes future reproductive strategies in regulating physical and motivational pathways of sexual behaviour. Conflicting and stressful parental relationships can lead children to believe that resources are limited, people are untrustworthy, and relationships are opportunistic. As they replicate their parents’ mating-oriented reproductive behaviour, they tend to have multiple sexual partners and erratic relationships. Children implicitly and explicitly model their sexual attitudes and behaviours on their parents, see engagement in non-marital sex as normative. Father absence however can be a byproduct of initial social and economic strain within the household (e.g. violence, lack of educational opportunities and cumulative life exposure to poverty can increase the likelihood of early sexual endeavours and pregnancy). The timing of first intercourse can be heritable - shorter alleles of the X-linked androgen receptor (AR) gene has been associated with aggression, impulsivity, high number of sexual partners, divorce in males and earlier ages of physical maturation in females.\n",
"In present generations it is more common to have children at an older age. Several factors may influence the decisions of parents when having their first baby. Such factors include educational, social and economic status.\n",
"There are many health consequences that spiral from a child giving birth at a young age. Children who are younger than the age of 18 are more likely to die do to aggressive birth whereas an older women will be okay. Young children who deliver babies are subject to diseases and many health related problems that can prevent them from conceiving another child. Furthermore, children who marry at a young age are typically not educated. They cannot use their education as an outlet to get out of abusive relationships. These children grow up taking the inferior role in the household and are forced to obey their husbands. Child brides are sheltered from their community and are not allowed to participate in communal events. Child brides who run away from their husbands are subject to violence in the form of physical beatings, sexual assault, and marriage.\n",
"Mothers with one or more immature daughters in addition to their infants are in contact with their infants less than those with no older immature daughters, because the mothers may pass the parenting responsibilities to their daughters. High-ranking mothers with older immature daughters also reject their infants significantly more than those without older daughters, and tend to begin mating earlier in the mating season than expected based on their dates of parturition the preceding birth season. Infants farther from the center of the groups are more vulnerable to infanticide from outside groups. Some mothers abuse their infants, which is believed to be the result of controlling parenting styles.\n",
"Developmental disorders are present from early life. Most improve as the child grows older, but some entail impairments that continue throughout life. There is a strong genetic component; more males are afflicted than females.\n",
"Prenatal malnutrition and early life growth patterns can alter metabolism and physiological patterns and have lifelong effects on the risk of cardiovascular disease. Children who are undernourished are more likely to be short in adulthood, have lower educational achievement and economic status, and give birth to smaller infants. Children often face malnutrition during the age of rapid development, which can have long-lasting impacts on health.\n"
] |
Does the 5 second rule actually work - how do germs attach themselves to things? | [Residence Time and Contact Time: Testing the 5 second rule](_URL_0_)
Conclusion, contamination can be detected almost immediately on contact. This was only done with *S. typhimurium* which has pili for attachment onto M cells in the body, these probably play a role in surface attachment as well.
This bacteria is motile by way of multiple flagella and many species of bacteria are motile. To move they need to be in an aqueous environment but in a dry environment many bacteria can survive from days to weeks waiting to find a more suitable environment. | [
"The five-second rule was also featured in an episode of the Discovery Channel series \"MythBusters\". There was no significant difference in the number of bacteria collected. The aspects that affect the contamination process is the moisture, surface geometry and the location. Ted Allen put the rule to the test in an episode of \"Food Detectives\", and found that bacteria will cling to food immediately. Vsauce, a YouTube channel, also dedicated a video to this topic.\n",
"Appendages may become \"uniramous\", as in insects and centipedes, where each appendage comprises a single series of segments, or it may be \"biramous\", as in many crustaceans, where each appendage branches into two sections. \"Triramous\" (branching into three) appendages are also possible.\n",
"The endodermis prevents water, and any solutes dissolved in the water, from passing through this layer via the apoplast pathway. Water can only pass through the endodermis by crossing the membrane of endodermal cells twice (once to enter and a second time to exit). Water moving into or out of the xylem, which is part of the apoplast, can thereby be regulated since it must enter the symplast in the endodermis. This allows the plant to control to some degree the movement of water and to selectively uptake or prevent the passage of ions or other molecules.\n",
"When a plant cell recognizes particles from damaged cells or particles from the pathogen, the plant launches a two-pronged resistance: a general short-term response and a delayed long-term specific response.\n",
"Bacteria such as \"Clostridium butyricum\" are used to separate fibres of jute, hemp and flax in the process of retting. The plants are immersed in water and when they swell, inoculated with bacteria which hydrolyze pectic substances of the cell walls and separate the fibres. Alternatively, the plants are spread out on the ground, where they become wetted by dew and ret naturally. These separated fibres are used to make ropes, sacks etc.\n",
"The FOIL rule cannot be directly applied to expanding products with more than two multiplicands, or multiplicands with more than two summands. However, applying the associative law and recursive foiling allows one to expand such products. For instance,\n",
"Some JSP containers support configuring how often the container checks JSP file timestamps to see whether the page has changed. Typically, this timestamp would be set to a short interval (perhaps seconds) during software development, and a longer interval (perhaps minutes, or even never) for a deployed Web application.\n"
] |
Did Vikings have music and/or art (paintings, sculptures, etc)? | Art is so much and hard to define. I would argue that the Vikings were very artistic. Look at their wood carvings on boats especially. There are some very fine details you can see this very day on the well preserved **Oseberg Ship** for example.
The Vikings worked with material they had plenty off. Therefor is there no marble statues you find south in Europe for example. What they did, beside carving tree, was decorating stones and stone walls. Not only did they carve illustrations on stones (Hunnestad Monument in Sweden), they wrote heathen poems and songs on them. An example is **Røksteinen** (Rök Runestone) in Sweden. This stone is actually the first piece of Sweden litterateur and tells stories from Norse mythology.
You ask for music. And there was music. They made songs at feasts, after battles, before battles and when heroic people passed away or were killed in battle. Our problem is that they did not write lyrics (as we know of) and neither did they know about notes. What we do know is what instruments that were used because we have found them preserved in burial grounds and such. Mostly instruments you blow in to make sound, flutes like pan flutes and *blokkfløyte*, lur/lure/lurr, (a long blowing horn), wooden lyre (Greek string instruments) and horns of different sorts.
**Sources:**
_URL_2_ a very good source for information about the Vikings available in English, Norwegian and some articles are in Danish.
Norwegian:
_URL_2_s/life/music/n-music-iceland.html (Viking music with focus on Icelandic music)
Danish:
_URL_1_
_URL_0_
| [
"Viking art, also known commonly as Norse art, is a term widely accepted for the art of Scandinavian Norsemen and Viking settlements further afield—particularly in the British Isles and Iceland—during the Viking Age of the 8th-11th centuries CE. Viking art has many design elements in common with Celtic, Germanic, the later Romanesque and Eastern European art, sharing many influences with each of these traditions.\n",
"Viking art, also known commonly as Norse art, is a term widely accepted for the art of Scandinavian Norsemen and Viking settlements further afield—particularly in the British Isles and Iceland—during the Viking Age of the 8th–11th centuries CE. Viking art has many design elements in common with Celtic, Germanic, the later Romanesque and Eastern European art, sharing many influences with each of these traditions.\n",
"Historical re-creations of Norse music have been attempted based on instruments found in Viking sites. The instruments used were the \"lur\" (a sort of trumpet), simple string instruments, wooden flutes and drums. Sweden has a significant folk-music scene. There is Sami music, called the \"joik\", which is a type of chant which is part of the traditional Sami animistic spirituality. Notable composers include Carl Michael Bellman and Franz Berwald.\n",
"Viking Age art is a term for the art of Scandinavia and Viking settlements elsewhere, especially in the British Isles, during the Viking Age. It has many elements in common with Celtic art, Romanesque art and East-European (Eurasian). The Vikings were active in the Nordic countries between the late Early Middle Ages and the early portion of the High Middle Ages. There are three main artistic styles from that period: Jelling style, Ringerike style, and Urnes style. Jelling is named after a Danish royal grave in Jutland and usually involves heavy animal designs. The Ringerike style includes foliage ornaments and interlacing. The style is named after the district in Norway where examples of Ringerike exist in local sandstone. The Ringerike style can also be seen in English manuscripts, and there are also some carvings in ivory which are done in this style. The Urnes style is named after the detailed designs on the carved doors of Urnes Stave Church in the Sognefjord. The style has influenced English Christian art.\n",
"Danish art goes back thousands of years with significant artifacts from the 2nd millennium BC, such as the Trundholm sun chariot. Art from modern Denmark forms part of the art of the Nordic Bronze Age, and then Norse and Viking art. Danish medieval painting is almost entirely known from church frescoes such as those from the 16th-century artist known as the Elmelunde Master.\n",
"A non-visual source of information for Viking art lies in skaldic verse, the complex form of oral poetry composed during the Viking Age and passed on until written down centuries later. Several verses speak of painted forms of decoration that have but rarely survived on wood and stone. The 9th century skald poet Bragi Boddason, for example, cites four apparently unrelated scenes painted on a shield. One of these scenes depicted the god Thor's fishing expedition, which motif is also referenced in a 10th-century poem by Úlfr Uggason describing the paintings in a newly constructed hall in Iceland.\n",
"A continuous artistic tradition common to most of north-western Europe and developing from the 4th century CE formed the foundations on which Viking Age art and decoration were built: from that period onwards, the output of Scandinavian artists was broadly focused on varieties of convoluted animal ornamentation used to decorate a wide variety of objects.\n"
] |
why are most cars sold in muted colors as opposed to bright ones? | Bright colors (except red) typically do not sell very well as compared to greyscale or muted colors. Not that many people want bright colors like green/cyan/yellow, and cars used for commercial purposes are almost exclusively greyscale.
New Car dealerships, especially smaller lots, do not want to stock something they believe won't sell at a profit. Manufactures will still make many color varieties by request for those who want them, so there is not much incentive to stock them at dealerships. | [
"The most popular car colours today are greyscale colours, with over 70% of cars produced globally being white, black, grey or silver. Red, blue and brown/beige cars range between 6% and 9% each, while all other colours amount to less than 5%.\n",
"Almost all the states prohibit the colors green, red and blue because these are used for emergency purposes only. States where there is a lot of traffic and have a lot of cities have stricter regulations due to the high risk of crashes. Police and the state government officials believe that bright colors at night could be dangerous for people who are also driving.\n",
"Fewer paint colours were available and fewer models. Many of the late cars, which were built between 1985 and 1986, were painted in an unsympathetic pale green or cream. Horizons had initially been available in more adventurous colours including orange, but many of these colours had gone out of fashion after the 1970s.\n",
"Viewed under optimum conditions and by daylight as intended, a well-made and well-preserved Autochrome can look startlingly fresh and vivid. Unfortunately, modern film and digital copies are usually made with a highly diffused light source, which causes loss of color saturation and other ill effects due to light scatter within the structure of the screen and emulsion, and by fluorescent or other artificial light which alters the color balance. The capabilities of the process should not be judged by the dull, washed-out, odd-colored reproductions commonly seen.\n",
"Custom cars sometimes have indirect lighting underneath, glowing a color like green or purple which could not be confused with that of an emergency or other vehicle's normal lighting. These can be provided by strips of tubes of cold-cathode fluorescent lighting, or LEDs.\n",
"Making modern film or digital copies of Autochromes introduces other problems, because a color system based on red, green, and blue is used to copy an image that exists within the red-orange, green, and blue-violet system, providing further opportunities for color degradation. Vintage reproductions of Autochromes in old books and magazines have often been noticeably hand-adjusted by the photoengravers in an effort to compensate for some of the difficulties of reproduction, and as a result they sometimes look more like hand-colored photographs than \"natural color\" ones. In short, it is very difficult to form an accurate impression of the appearance of any Autochrome image without seeing the original \"in person\" and correctly illuminated.\n",
"The early models had colorful unpainted bodies which was a main selling point (Ralston 2008, 25–26). While earlier models tended to feature semi-realistic colors similar to what contemporary car manufacturers were offering, later models tended to stray away from realism and offered vibrant, less realistic colors, such as bright orange or lime green. In the mid-1960s, Norev toyed with the idea of adopting colorless plastic bodies which would then be spray-painted in metallic colors. The experiment seemed to have been fairly short-lived, with only 5 known models released: the Ford Anglia 105E Deluxe, the Lancia Flaminia, the Fiat 2300, the DAF Daffodil and the Morris Mini 850. \n"
] |
What exactly is an analog computer and how do they work? | The linked example is actually a digital not an analog computer. The idea in that comic isn't that complicated. A digital computer keeps track of 1s and 0s as electric current and based on those does operations to them. Well, there's no reason you can't do something similar with stones, say having a stone by itself represent a 0 and having a pair of stones represent a 1. Now, you can then follow through and do everything single operation to move the stones just like a computer would. If one is patient and follows through the detailed instructions (in your comic the person is a very bored immortal), you could run any calculation a computer could run. | [
"An analog computer or analogue computer is a type of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities symbolically, as their numerical values change. As an analog computer does not use discrete values, but rather continuous values, processes cannot be reliably repeated with exact equivalence, as they can with Turing machines. Unlike machines used for digital signal processing, analog computers do not suffer from the discrete error caused by quantization noise. Instead, results from analog computers are subject to continuous error caused by electronic noise.\n",
"An analog computer is a form of computer that uses electrical, mechanical or hydraulic phenomena to model the problem being solved. More generally an analog computer uses one kind of physical quantity to represent the behaviour of another physical system, or mathematical function. Modeling a real physical system in a computer is called simulation.\n",
"Analogue electronics () are electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two levels. The term \"analogue\" describes the proportional relationship between a signal and a voltage or current that represents the signal. The word analogue is derived from the Greek word (analogos) meaning \"proportional\".\n",
"Analog device is usually a combination of both analog machine and analog media that can together measure, record, reproduce, or broadcast continuous information, for example, the almost infinite number of grades of transparency, voltage, resistance, rotation, or pressure. In theory, the continuous information (also analog signal) has an infinite number of possible values with the only limitation on resolution being the accuracy of the analog device.\n",
"Functional analogs (or functional analogues) are entities (models, representations, etc.) that can be replaced, to fulfill the same function. When the entities in question are formally represented by black boxes, the concept of \"analog\" is related to \"same behavior\": they take the same output sequence when submitted to the same input sequence.\n",
"Mechanical computing devices are classified according to the means by which they represent data. An analog computer represents a datum as a voltage, distance, position, or other physical quantity. A digital computer represents a piece of data as a sequence of symbols drawn from a fixed alphabet. The most common digital computers use a binary alphabet, that is, an alphabet of two characters, typically denoted \"0\" and \"1\". More familiar representations, such as numbers or letters, are then constructed from the binary alphabet. Some special forms of data are distinguished. A computer program is a collection of data, which can be interpreted as instructions. Most computer languages make a distinction between programs and the other data on which programs operate, but in some languages, notably Lisp and similar languages, programs are essentially indistinguishable from other data. It is also useful to distinguish metadata, that is, a description of other data. A similar yet earlier term for metadata is \"ancillary data.\" The prototypical example of metadata is the library catalog, which is a description of the contents of books.\n",
"Analog computers often have a complicated framework, but they have, at their core, a set of key components which perform the calculations, which the operator manipulates through the computer's framework.\n"
] |
do canadians have the same rights and freedoms as americans? | The US and Canada have different legal systems. While many rights and freedoms overlap between both countries you should never apply any legal advice regarding the US into the Canadian system. | [
"Similarly, Justice Hall argues that the \"Canadian Bill of Rights\" can only be fulfilled if it has the effect repudiating \"discrimination in every law of Canada by reason of race, national origin, colour, religion or sex in respect of the human rights and fundamental freedoms set out in s. 1 in whatever way that discrimination may manifest itself not only as between Indian and Indian but as between all Canadians whether Indian or non-Indian.\"\n",
"In keeping with this, it is often asserted that Canadian government policies such as publicly funded health care, higher taxation to distribute wealth, outlawing capital punishment, strong efforts to eliminate poverty in Canada, an emphasis on multiculturalism, imposing strict gun control, leniency in regard to drug use and most recently legalizing same-sex marriage make their country politically and culturally different from the United States.\n",
"In \"The Rights Revolution\", Ignatieff identifies three aspects of Canada's approach to human rights that give the country its distinctive culture: 1) On moral issues, Canadian law is secular and liberal, approximating European standards more closely than American ones; 2) Canadian political culture is social democratic, and Canadians take it for granted that citizens have the right to free health care and public assistance; 3) Canadians place a particular emphasis on group rights, expressed in Quebec's language laws and in treaty agreements that recognize collective aboriginal rights. \"Apart from New Zealand, no other country has given such recognition to the idea of group rights,\" he writes.\n",
"Human rights in Canada are now given legal protections by the dual mechanisms of constitutional entitlements and statutory human rights codes, both federal and provincial. There are two main federal pieces of human rights legislation in Canada; the \"Canadian Charter of Rights and Freedoms\" and the \"Canadian Human Rights Act\". \n",
"According to journalist Lysiane Gagnon, Canadians \"don't share common values.\" She notes that while many ideas - such as medicare, bilingualism, and multiculturalism - are sometimes characterized as Canadian values, \"many Canadians are against all or some of these.\"\n",
"The Canadian Human Rights Act is considered quasi-constitutional legislation, and applies to federal government agencies and Crown corporations including the Canadian Armed Forces. It acts to prohibit discrimination on specified grounds, such as race, sex, age, religion, and in the context of employment and publicly available services.\n",
"A 2013 Statistics Canada survey found that an \"overwhelming majority\" of Canadians shared the values of human rights (with 92% of respondents agreeing that they are a shared Canadian value), respect for the law (92%) and gender equality (91%). There was considerably less agreement among Canadians over whether ethnic and cultural diversity, linguistic duality, and respect for aboriginal culture were also shared Canadian values.\n"
] |
Books on Finland During the Cold War | You could look at *Urho Kekkonen: A Statesman for Peace* edited by Keijo Korhonen, written in 1975.
The book focuses on the long-term president of Finland, Urho Kekkonen, and his policies with respect to foreign relations with the Soviet Union and with Western Europe. It includes contributions from Finnish, American and other international scholars. Since it was written in 1975, it is written in the context of an ongoing Cold War. So, it lacks information that has become available since the opening of the Soviet archives in the last 25 years. Also, it can't discuss the last 10 years of the Kekkonen presidency (until 1986), which were still to come when the book was published.
With all those caveats, I think the book is highly relevant to the question of Finlandization. | [
"Hautamäki's book brings forth details and information about the last Finnish wars, which were not discussed in the Finnish main media - nor elsewhere - during the Cold War period, due to the sensitive and friendly Finnish-Soviet relations, in particular.\n",
"Ohto Manninen has focused foremost on second world war history, and this has resulted in books like \"Toteutumaton valtioliitto\" (1977), which treats Finland and Sweden after the Winter war, \"Suur-Suomen ääriviivat\" (1980), which is about Finland's politics on Germany 1941, and \"Talvisodan salatut taustat\" (1994), a survey on the Soviet plans of operations before the Winter war, and collections of articles \"Molotovin cocktail - Hitlerin sateenvarjo\" (1994) and \"Stalinin kiusa - Himmlerin täi\" (2002).\n",
"It is certainly a shame that, in the year of the 70th anniversary of the victory in World War II, the authors have seemingly forgotten the Soviet Army's heroic contribution to the liberation of northern Norway from Nazi occupiers, decided, in the worst traditions of the Cold War, to scare Norwegian spectators with the nonexistent threat from the east. The Russian embassy had been informed in an early stage of the work on the series.\n",
"Fire and Ice: The Winter War of Finland and Russia is a documentary film, produced, written and directed by Ben Strout. It shows how the Finnish–Russian Winter War of 1939 influenced World War II and how Finland mobilized against the world’s largest military power.\n",
"When the Winter War broke out, suspicions against Finland's \"hazardous foreign politics\" remained strong, most importantly among leading Social Democrats in Sweden. As the Winter War ended with the loss of Finnish Karelia, this was generally seen as the failure of the neutralist Scandinavia-orientation. As Soviet disapproval ended the discussions on a Swedish-Finnish defence cooperation in 1940, the Scandinavist line had run into a blind alley — and Fagerholm had no more say in the policy discussions that ultimately led to close dependency of Nazi Germany, German troops on Finnish soil, revanchism, and to co-belligerence in the Continuation War.\n",
"In the 1990s and 2000s, especially after the Moscow Archives opened, there have been hundreds of articles considering the Winter War. However, only dozens of monographs have been published. Due to the language barrier, most Russian historians have not exploited Finnish writings and sources.\n",
"During the Second World War, Finland fought two wars against the Soviet Union: the Winter War of 1939–1940, resulting in the loss of Finnish Karelia, and the Continuation War of 1941–1944 (with considerable support from Nazi Germany resulting in a swift invasion of neighboring areas of the Soviet Union), eventually leading to the loss of Finland's only ice-free winter harbour Petsamo. The Continuation War was, in accordance with the armistice conditions, immediately followed by the Lapland War of 1944–1945, when Finland fought the Germans to force them to withdraw from northern Finland back into Norway (then under German occupation). Finland was not occupied; its army of over 600,000 soldiers, saw only 3,500 prisoners-of-war. About 96,000 Finns lost their lives, or 2.5% of a population of 3.8 million; civilian casualties were under 2,500.\n"
] |
what is that warm, fuzzy feeling in your stomach when you fall in love with someone? | That fuzzy feeling is actually a baby that starts to grow, if u love each other then it continues to grow until it comes out but if things don't work out then it shrinks back to inexistence | [
"Scientific study on the topic of lovesickness has found that those in love experience a kind of high similar to that caused by illicit drugs such as cocaine. In the brain, certain neurotransmitters — phenethylamine, dopamine, norepinephrine and oxytocin — elicit the feeling of high from \"love\" or \"falling in love\" using twelve different regions of the brain. These neurotransmitters mimic the feeling of amphetamines.\n",
"This can help explain why no love can feel quite the same as that \"first\". These \"firsts\" can generate sensations so new and unfamiliar that the experience feels almost unreal. Besides emotional engagement, these experiences also have a heavy dose of novelty. Novelty simply driving up dopamine and norepinephrine (brain systems associated with focus and paying attention and rewards). A first romantic relationship is the only time in which an individual is in \"love\" without ever having been hurt from such a relationship. If a person meets someone who reminds them of an ex, whether physically or a similarity in attitudes, gestures, voice, or interests, it may engage the representation in their memory. And since their first love, by result of its novelty and emotional significance, is potentially the most prominent, it may be the representation that is summoned when they meet a potential someone new, which effects the way they see that new relationship. Their old feelings, motivations, and expectations are all transferred into their memory, which can cause them to (if their new found partner reminds them of an ex) begin to repeat behaviors that they engaged in with that ex.\n",
"Love can start with any of these three feelings, Fisher maintains. Some people have sex with someone new and then fall in love. Some fall in love first, then have sex. Some feel a deep feeling of attachment to another, which then turns into romance and the sex drive. But the sex drive evolved to initiate mating with a range of partners; romantic love evolved to focus one's mating energy on one partner at a time; and attachment evolved to enable us to form a pair bond and rear young together as a team.\n",
"BULLET::::- To feel an affection for an individual of the opposite sex so intense that one would not regret sacrificing anything for that person; the person is constantly on one’s mind, prompting the wish to always be together and share a private world; one feels happy when that desire is satisfied and anxious or depressed should the slighted doubt about that person’s affections arise. (tr. The Japan Forum 2005)\n",
"Sweet then wakes up and in a plot twist, it is revealed that everything from the disco ball incident was all a dream. He then tells Shorty and Sandy that he loves them both and he had \"a hell of a dream\".\n",
"It was the tenderest love you could imagine... I was fairly experienced with men, but with Felice I reached a far deeper under-standing of sex than ever before...There was an immediate attraction, and we flirted outrageously... I began to feel alive as I never had before...She was my other half, literally my reflection, my mirror image, and for the first time I found love aesthetically beautiful, and so tender...Twice since she left, I've felt her breath, and a warm presence next to me. I dream that we will meet again - I live in hope.\n",
"It was the tenderest love you could imagine... I was fairly experienced with men, but with Felice I reached a far deeper under-standing of sex than ever before...There was an immediate attraction, and we flirted outrageously... I began to feel alive as I never had before...She was my other half, literally my reflection, my mirror image, and for the first time I found love aesthetically beautiful, and so tender...Twice since she left, I've felt her breath, and a warm presence next to me. I dream that we will meet again - I live in hope.\n"
] |
Are there precious resources (ie gold, copper, titanium) on the moon? Would it be possible to mine them? | The moon actually has a fairly high abundance of titanium compared to most bodies in the solar system--so far as we're aware--and in general you should expect to be able to find all metals on the moon in rates comparable to Earth. It's nonmetals like carbon, nitrogen, and phosphorus--all necessary to life--that are hard to come by (oxygen is present in water ice and in silicate and other oxide minerals). | [
"Prospecting operations will be aimed at locating concentrations of extractable lunar gems and minerals. High grade titanium, rare-earth metals and helium-3 (a potential fusion reactor fuel) are all known to exist on the Moon. Low cost flight of concentrated ores to the Earth is feasible using Solar Powered, electromagnetic \"Rail guns\", and other technologies.\n",
"On the makeup of the Moon rocks, Kaysing asked: \"Why was there never a mention of gold, silver, diamonds or other precious metals on the moon? Wasn't this a viable consideration? Why was this fact never dicussed [\"sic\"] in the press or by the astronauts?\" Geologists realize that gold and silver deposits on Earth are the result of the action of hydrothermal fluids concentrating the precious metals into veins of ore. Since in 1969 water was believed to be absent on the Moon, no geologist would bother discussing the possibility of finding these on the Moon in any great amount.\n",
"Moon rocks collected during the course of lunar exploration are currently considered priceless. In 2002, a safe was stolen from the Lunar Sample Building that contained minute samples of lunar and Martian material. The samples were recovered, and NASA estimated their value during the ensuing court case at about $1 million for 10 oz. (285 g) of material.\n",
"In response, it has been suggested that platinum, cobalt and other valuable elements from asteroids may be mined and sent to Earth for profit, used to build solar-power satellites and space habitats, and water processed from ice to refuel orbiting propellant depots.\n",
"Lunar materials could facilitate continued exploration of the Moon itself, facilitate scientific and economic activity in the vicinity of both Earth and Moon (so-called cislunar space), or they could be imported to the Earth's surface where they would contribute directly to the global economy. The Moon is known to be poor on carbon and nitrogen, and rich in metals and in atomic oxygen, but their distribution and concentrations are still unknown. Further exploration will reveal additional concentrations of economically useful materials on the Moon, and whether or not these will be economically exploitable will depend on the value placed on them and on the energy and infrastructure available to support their extraction. For in situ resource utilization (ISRU) to be applied successfully on the Moon, landing site selection is imperative, as well as identifying suitable surface operations and technologies.\n",
"Ouyang Ziyuan, a geologist and chemical cosmologist, was among the first to advocate the exploitation not only of known lunar reserves of metals such as titanium, but also of helium-3, an ideal fuel for future nuclear fusion power plants. He currently serves as the chief scientist of the Chinese Lunar Exploration Program. Another scientist, Sun Jiadong, was assigned as the general designer, while scientist Sun Zezhou was assigned as the deputy general designer. The leading program manager is Luan Enjie.\n",
"Cambodia has few natural resources, mainly gold and some non-metallic minerals. Artisanal mining often extracts gold bearing alluvium, which originated from quartz veins in different rocks. Gold was found at Suptrup in 1877 and mined until 1940.\n"
] |
why does your leg jerk when you hit the ligament below the knee? | I'm not a native speaker but I'm pretty sure I know what your question is.
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The answer is kinda simple: It's supposed to tense the leg when falling/jumping on the ground to catch the bodies weight. The "shock" that goes through your body from landing would trigger this mechanism and tense (?) the leg to catch your fall.
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If this wasn't the case, not only would you fall over more often, even when it's just a 1 or 2 meter drop, but you would also hurt your knee and ankles a lot more (yes theres a similiar reflex for your ankles)
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If you want more information on how this works biologically, I suggest you look it up on your own, it's been a while since my last biology lesson. | [
"Because the medial collateral ligament resists widening of the inside of the knee joint, the ligament is usually injured when the outside of the knee joint is struck. This force causes the outside of the knee to buckle, and the inside to widen. When the MCL is stretched too far, it is susceptible to tearing and injury. This is the injury seen by the action of \"clipping\" in a football game.\n",
"The knee jerk is the popularly known stretch reflex (involuntary kick of the lower leg) induced by tapping the knee with a rubber-headed hammer. The hammer strikes a tendon that inserts an extensor muscle in the front of the thigh into the lower leg. Tapping the tendon stretches the thigh muscle, which activates stretch receptors within the muscle called muscle spindles. Each muscle spindle consists of sensory nerve endings wrapped around special muscle fibers called spindle fibers (also called intrafusal fibers). Stretching a spindle fiber initiates a volley of impulses in the sensory neuron (a I-a neuron) attached to it. The impulses travel along the sensory axon to the spinal cord where they form several kinds of synapses:\n",
"Both collateral ligaments are taut when the knee joint is in extension. With the knee in flexion, the radius of curvatures of the condyles is decreased and the origin and insertions of the ligaments are brought closer together which make them lax. The pair of ligaments thus stabilize the knee joint in the coronal plane. Therefore, damage and rupture of these ligaments can be diagnosed by examining the knee's mediolateral (side) stability.\n",
"Of all major joints, the ankle is the most commonly injured. If the outside surface of the foot is twisted under the leg during weight bearing, the lateral ligament, especially the anterior talofibular portion, is subject to tearing (a sprain) as it is weaker than the medial ligament and it resists inward rotation of the talocrural joint.\n",
"Knee ligament injuries are a common injury in wrestling. One being an injury to the Medial collateral ligament which is also known as the MCL and is located on the inside. Another common injury to the knee is on the outside Lateral Collateral Ligament which is known as the LCL. Leg or knee injuries are commonly caused by over twisting the leg outward from the middle of the body.\n",
"A ligament is a small band of dense, white, fibrous elastic tissue. Ligaments connect the ends of bones together in order to form a joint. Most ligaments limit dislocation, or prevent certain movements that may cause breaks. Since they are only elastic they increasingly lengthen when under pressure. When this occurs the ligament may be susceptible to break resulting in an unstable joint.\n",
"A change of direction can cause a twisting motion through the body but in particularly the knee. AFL players do this twisting motion quite often but it is the unlucky ones that can do some serious damage. It only take one slight twist for the ACL to rupture. A sudden change of direction can force the knee to give way seen that it is the joint that connects the upper and lower leg. If the knee gives way then the knee will shut down as it will collapse leaving potential damage on the ACL.\n"
] |
how cameras work. how do they capture an image and print it? | Imagine if you were holding a piece of paper with a bunch of glue. Now imagine if someone put glitter in front of a fan, the paper would catch the glitter and you'd have a picture.
Now imagine if your sister stood in between the fan with a metal door she could open. You tell her to open it for 1 second only, and you'll catch what you want to see on your glue paper. In this example, your sister is kind of like a camera and the glue paper is your camera's really sensitive image sensor.
____
Bonus:
Imagine if your glitter fan was making a rainbow of colors. You tell your sister to open it for 10 seconds instead of 1 second, and you get more glitter and your picture is brighter, fine.
But if your dog runs through the blue half of the rainbow during those 10 seconds, he'll mess up and blur the glitter. Now the blue part of your rainbow picture is blurry.
In real life, someone probably had to take the picture for a "long time" e.g. 1/2 of a second instead of 1/100 of a second, and something moved fast enough during this time, enough to blur. The people in the front stood still for the whole 1/2 second and are fine. | [
"Photographers control the camera and lens to \"expose\" the light recording material to the required amount of light to form a \"latent image\" (on plate or film) or RAW file (in digital cameras) which, after appropriate processing, is converted to a usable image. Digital cameras use an electronic image sensor based on light-sensitive electronics such as charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology. The resulting digital image is stored electronically, but can be reproduced on a paper.\n",
"Digital photography uses cameras containing arrays of electronic photodetectors to capture images focused by a lens, as opposed to an exposure on photographic film. The captured images are digitized and stored as a computer file ready for further digital processing, viewing, electronic publishing, or digital printing.\n",
"Traditional cameras capture light onto photographic plate or photographic film. Video and digital cameras use an electronic image sensor, usually a charge coupled device (CCD) or a CMOS sensor to capture images which can be transferred or stored in a memory card or other storage inside the camera for later playback or processing.\n",
"Camcorders use accelerometers for image stabilization, either by moving optical elements to adjust the light path to the sensor to cancel out unintended motions or digitally shifting the image to smooth out detected motion. Some stills cameras use accelerometers for anti-blur capturing. The camera holds off capturing the image when the camera is moving. When the camera is still (if only for a millisecond, as could be the case for vibration), the image is captured. An example of the application of this technology is the Glogger VS2, a phone application which runs on Symbian based phones with accelerometers such as the Nokia N96. Some digital cameras contain accelerometers to determine the orientation of the photo being taken and also for rotating the current picture when viewing.\n",
"At many newspapers, photographers, reporters and editors use digital cameras to take photographs and download selected photographs using a card reader. The photographs are cropped and edited using a program such as Adobe Photoshop.\n",
"Cinematographers use a lens to focus reflected light from objects into a real image that is transferred to some image sensor or light-sensitive material inside a movie camera. These exposures are created sequentially and preserved for later processing and viewing as a motion picture. Capturing images with an electronic image sensor produces an electrical charge for each pixel in the image, which is electronically processed and stored in a video file for subsequent processing or display. Images captured with photographic emulsion result in a series of invisible latent images on the film stock, which are chemically \"developed\" into a visible image. The images on the film stock are projected for viewing the motion picture.\n",
"Digital images may be conveniently stored on a personal computer or in off-line storage such as small memory cards. Professional-grade digital cameras can store pictures in a raw image format, which stores the output from the sensor, rather than processing it immediately to form an image. When edited in suitable software, such as Adobe Photoshop or the GNU program GIMP (which uses dcraw to read raw files), the user may manipulate certain parameters, such as contrast, sharpness, or colour balance before producing an image. JPEG images can be similarly manipulated, though usually less precisely; software for this purpose may be provided with consumer-grade cameras. Digital photography allows the quick collection of a large quantity of archival documents, bringing convenience, lower cost, and increased flexibility in using the documents.\n"
] |
why don't gas pumps themselves accept cash? | Because if they did accept cash, they would need to be stocked with cash to dispense change and also have added security features to protect that cash and any cash you add to it. They would also need to hire someone to come and restock and collect the cash. No, they can not just get the clerk at the station to do it because you don't want them skimming off the top. | [
"In states such as Oregon and New Jersey, where pumping your own gas is outlawed, automated cash handling has played an important role as a crime deterrent and economical sound system. Gas attendants now do not have to worry about being burglarized. With automated cash systems in place at these gas stations, everything is used by computer, making transactions faster than ever. These systems also allow petroleum companies to save money and ensure a higher level of security.\n",
"The vast majority of gas pumps with pay-at-the-pump capabilities will place a temporary hold on a certain amount of money, generally $75-$150, in a customer's account following the use of a debit or credit card to make a purchase. The pump must do this pre-authorization before allowing a customer to pump fuel to guarantee funds are available to pay for said fuel. The length of time the funds are placed on hold, and are unavailable to the customer, is totally dependent on how fast the customer's bank processes the transaction. Depending on the bank, it can take a few minutes to a few business days before the funds on hold are released.\n",
"A pump is a mechanical device generally used for raising liquid from a lower level to higher one. This is achieved by creating a low pressure at the inlet and high pressure at the outlet of the pump. Due to low inlet pressure, the liquid rises from where it is to be stored or supplied. However, work has to be done by a prime mover to enable it to impart mechanical energy to the liquid which ultimately converts into pressure energy.\n",
"Most centrifugal pumps are not self-priming. In other words, the pump casing must be filled with liquid before the pump is started, or the pump will not be able to function. If the pump casing becomes filled with vapors or gases, the pump impeller becomes gas-bound and incapable of pumping. To ensure that a centrifugal pump remains primed and does not become gas-bound, most centrifugal pumps are located below the level of the source from which the pump is to take its suction. The same effect can be gained by supplying liquid to the pump suction under pressure supplied by another pump placed in the suction line. The process of filling the pump with liquid is called priming.\n",
"In the 1970s, USA Gas became the first gasoline retailer to experiment with self-service pay at the pump technology and entered into an agreement with Allstate Bank of Southern California allowing banking customers to automatically debit their accounts directly from the pump.\n",
"Pay at the pump is a system used at some filling stations where customers can pay for their fuel by inserting a credit or debit card or fuel card into a slot on the pump, bypassing the requirement to make the transaction with the station attendant or to walk away from one's vehicle. A few areas have gas stations that use electronic tolling transponders as a method of payment, such as Via Verde in Portugal.\n",
"As natural gas injections (positive) represent additional demand, withdrawals (negative) represent an additional source of supply which can be accessed quickly. The more storage banks like shale deposits used give more cushion for the natural gas markets.\n"
] |
Were the founding fathers radicals? | The most radical of the generally-recognized “founding fathers” was Thomas Paine—his views on politics and religion, and his bitterness at what he felt was betrayal by other revolutionaries, eventually made him an outcast in American society.
Paine also took an active part in the French Revolution—but by French standards he was only moderately radical, and his opposition to the more-extreme Montagnards almost cost him his life. So using Paine as a yardstick, the American revolutionaries weren’t terribly radical even for the time. | [
"The \"Founding Fathers\" were strong advocates of republican values, especially Samuel Adams, Patrick Henry, George Washington, Thomas Paine, Benjamin Franklin, John Adams, Thomas Jefferson, James Madison and Alexander Hamilton.\n",
"These writers, and others such as the Abbé Sieyès, one of the main authors of the Declaration of the Rights of Man and of the Citizen, became known as the \"philosophes\". They came from the wealthy upper class or Third Estate, sought a society founded upon talent and merit, rather than a society based on heredity or caste. Their ideas were strongly influenced by those of John Locke in England. They introduced the values of liberty and equality which became the ideals of the French Republic founded at the end of the century. They defended the freedom of conscience and challenged the role of religious institutions in society. For them, tolerance was a fundamental value of society. When the Convention placed the ashes of Voltaire in the Pantheon in Paris, they honored him as the man who \"taught us to live as free men.\"\n",
"The key idea of \"aristocratic radicalism\" went on to influence most of the later works of Brandes and resulted in voluminous biographies \"Wolfgang Goethe\" (1914–15), \"Francois de Voltaire\" (1916–17), \"Gaius Julius Cæsar\" 1918 and Michelangelo (1921).\n",
"In April 1988 Walden joined Norman Tebbit, Lord Chapple and Lord Marsh in founding the Radical Society, designed to combat \"privilege, hierarchy, bureaucracy and collectivism\" and to put in their place individualist solutions.\n",
"The philosophical radicals, as a group, came to prominence in the 1820s. When radicalism re-emerged from the defeat of the Six Acts, it was (in Elie Halévy’s words) “the Radicalism – respectable, middle-class, prosaic, and calculating – of Bentham and his followers”. Central to their political aims was the reduction of aristocratic power, privilege and abuse. In his article in the opening number of the Westminster Review, James Mill dissected the aristocratic nature of the British Constitution, the House of Commons largely nominated by some hundred borough-managers, the landlord culture propped up by the Law and the Church. His son veered in many respects from his views, but never ceased (in his own words) to consider “the predominance of the aristocratic classes, the noble and the rich, in the English Constitution, an evil worth any struggle to get rid of”.\n",
"The Founding Fathers were strong advocates of republican values, particularly Samuel Adams, Patrick Henry, John Adams, Benjamin Franklin, Thomas Jefferson, Thomas Paine, George Washington, James Madison, and Alexander Hamilton, which required men to put civic duty ahead of their personal desires. Men had a civic duty to be prepared and willing to fight for the rights and liberties of their countrymen. John Adams wrote to Mercy Otis Warren in 1776, agreeing with some classical Greek and Roman thinkers: \"Public Virtue cannot exist without private, and public Virtue is the only Foundation of Republics.\" He continued:\n",
"Intellectuals played a powerful role in all the movements, for example a major spokesman for radicalism was Émile Chartier (1868–1951), who wrote under the pseudonym of \"Alain.\" He was a leading theorist of radicalism, and his influence extended through the Third and Fourth Republics. He stressed individualism, seeking to defend the citizen against the state. He warned against all forms of power – military, clerical, and economic. To oppose them, he exalted the small farmer, the small shopkeeper, the small town, and the little man. He idealized country life and saw Paris as a dangerous font of power.\n"
] |
how do gas stations make money, or account for the volatility when oil prices are falling? do they "buy" the gas when the fuel trucks refill the station or are their profits calculated at a spot price each day based on how much gas they sell? | Just for clarity—gas stations make minimal profits of actually selling gas. That’s not the business they are in. Yup, sounds odd, but gas stations aren’t really in the gas business
Gas stations make almost all of their profit in their convenience store—not gas! Cigarettes are particularly major for their profits.
The gas just gets customers to go into their convenience store is all. They make their money because their margins in the store are big and they sell lots of cigarettes and alcohol. | [
"Individual gas stations in the United States have little if any control over gasoline prices. The wholesale price of gasoline is determined according to area by oil companies which supply the gasoline, and their prices are largely determined by the world markets for oil. Individual gas stations are unlikely to sell gasoline at a loss, and the profit margin—typically between 7 and 11 cents a U.S. gallon—that they make from gasoline sales is limited by competitive pressures: a gas station which charges more than others will lose customers to them. Most gas stations try to compensate by selling higher-margin food products in their convenience stores.\n",
"Due to heavy fluctuations of gasoline price in the United States, some gas stations offer their customers the option to buy and store gas for future uses, such as the service provided by First Fuel Bank.\n",
"On 30 August 2005, many gas stations raised prices by a considerable amount putting most of America over $3.00/gallon, as shown in the movie. On 1 September 2005, gas stations throughout the country began to run out of fuel due to worries of mass shortages. Some stations in Atlanta, Georgia sold gas at nearly $6/gallon. Most of this was due to panic buying, as noted in the film, rather than physical shortage. Subsequently, as the extent of the damage became clearer, prices eased.\n",
"On September 19, 2007, Pickens told CNBC that the price of oil could rise to $100 per barrel. \"Demand is up and supply is flat, so it's got to go on up,\" said Pickens, whose company is betting on natural gas for vehicles. \"I can give you an Oklahoma guarantee that natural gas will never sell above diesel and gasoline prices\" as fuel for vehicles, Pickens added.\n",
"Crude oil is the greatest contributing factor when it comes to the price of gasoline. This includes the resources it takes for exploration, to remove it from the ground, and transport it. Between 2004 and 2008, there was an increase in fuel costs due in large part to a worldwide increase in demand for crude oil. Prices leapt from , causing a corresponding increase in gas prices. On the supply side, OPEC (or the Organization of the Petroleum Exporting Countries) has a great deal to do with the price of gasoline, both in the United States and around the world. The speculation of oil commodities can also affect the gasoline market.\n",
"Aside from this breakdown, many other factors affect gasoline prices. Extreme weather, war or natural disaster in areas where oil is produced can also in turn raise the price of a gallon of gasoline. Legislation by several states for cleaner burning fuel also affects certain areas' prices of gasoline.\n",
"In order to save money, some consumers in Canada and the United States inform each other about low and high prices through the use of gasoline price websites. Such websites allow users to share prices advertised at filling stations with each other by posting them to a central server. Consumers then may check the prices listed in their geographic area in order to select the station with the lowest price available at the time. Some television and radio stations also compile pricing information via viewer and listener reports of pricing or reporter observations and present it as a regular segment of their newscasts, usually before or after traffic reports. These price observations must usually be made by reading the pricing signs outside stations, as many companies do not give their prices by telephone due to competitive concerns. In Canada, it is against federal law to provide any gas pricing from a gas station via phone. It is a criminal offence to have written or verbal arrangements with competitors, suppliers or customers for:\n"
] |
what’s the difference between a stratocaster and a les paul. | A big **difference between** the **Stratocaster** and the **Les Paul** is their scale length—the length of the strings measured from the nut to the bridge. ... The **Stratocaster's** longer scale results **in a** brighter, more chiming sound whereas the LP's shorter scale is to an extent responsible for its rounder, warmer sound.
First answer on Google.
Further explanation from me would be Stratocaster single coil pickups and less wood lending to a brighter and crisper tone, Les Paul having much more wood, heavier construction and humbuckers lending themselves to a thicker, fuller tone with less buzz and crackling. The amount of wood used in the construction changes the dynamics of the instrument, less so with a bolt on neck than a neck through or set neck but it does have an effect on tone the less. | [
"The Fender Stratocaster is a model of electric guitar designed from 1952 into 1954 by Leo Fender, Bill Carson, George Fullerton, and completed by Freddie Tavares. The Fender Musical Instruments Corporation has continuously manufactured the Stratocaster from 1954 to the present. It is a double-cutaway guitar, with an extended top \"horn\" shape for balance like the Precision base guitar. Along with the Gibson Les Paul and Fender Telecaster, it is one of the most-often emulated electric guitar shapes. \"Stratocaster\" and \"Strat\" are trademark terms belonging to Fender. Guitars that duplicate the Stratocaster by other manufacturers are usually called \"S-Type\" or \"ST-type\" guitars.\n",
"The name \"Oltcit\" comes from the region of Oltenia in Romania, with \"cit\" being an abbreviation of Citroën. The Oltcit logo is also similar to the Citroën one, but features only one chevron, as opposed to the two found on Citroën's logo, plus the letter \"O\".\n",
"The name \"Oltcit\" comes from the region of Oltenia in Romania, with \"cit\" being an abbreviation of Citroën. The Oltcit logo is also similar to the Citroën one, but features only one chevron, as opposed to the two found on Citroën's logo, plus the letter \"O\".\n",
"The Les Paul 100 is outwardly very similar to the original Les Pauls. It has a traditionally shaped, single cut mahogany body, thinner than most Les Paul models, with two tone controls, two volume controls and the three position Rhythm/Treble switch. It also sports a stopbar tailpiece and Tune-o-matic bridge, like the higher end models.\n",
"The Les Paul 100 has a bolt-on neck rather than the typical Les Paul set-neck and it also has a nato body thinner than most Les Pauls (the \"top\" being carved into a standard thickness body blank, as with the early '90s Gibson \"The Paul II\"). It comes with 2 open-coil humbucker pickups (700T/650R), The Les Paul 100 is cut to the same specs as Les' 1952 original, nato neck, rosewood fretboard (with dot inlays) and a tune-o-matic bridge. It also lacks the Grover Machine Heads in recent production. The Epiphone LP100 does not have binding.\n",
"A panoply is a complete suit of armour. The word represents the ancient Greek πανοπλία (\"panoplía\"), where the word πᾶν \"pân\" means \"all\", and ὅπλον \"hóplon\", \"arms\". Thus \"panoply\" refers to the full armour of a hoplite or heavy-armed soldier, i.e. the shield, breastplate, helmet and greaves, together with the sword and lance.\n",
"The term maillot was inducted into the English dictionary in 1928; it derived from the French phrase for swaddling clothes. In the French language, the word maillot means \"shirt\" and is used to distinguish leaders in the Tour de France. The modern French term for a swimsuit, maillot de bain, also makes use of the word. The name \"tanksuit\" or \"tank suit\" (as well as \"tank top\") alludes to the \"tank\" or pool in which the wearer swims.\n"
] |
why is it that rap disputes are/were far more common, and typically more violent than other genres of music? | Rap and Hip-Hop grew out of gang culture: dance and rap battles were a way for gangs to solve minor disputes without resorting to violence.
This meant that many early Rap and Hip-Hop stars came out of gang culture; and when their rap battles grew heated and serious; they did what they had before: turned to violence. Meanwhile, most other music genres didn't (and don't) have the same association with social groups that solve their problems with violence, and so conflicts between them are solved in different ways. | [
"A controversial issue hotly debated in rap/hip-hop culture throughout its history is the use of violence and aggression as a feature of the hardcore styles of its music. But its social significance can't be removed from the factors it came from that births this debate. The prevalence of misogyny, sexism, and sexual violence in the lyrics of the most popular gangsta rap lyrics launched a public debate about obscenity and indecency, including U.S. Senate hearings in the mid-1990s. The graphic depiction of women as background decoration in music videos and as \"bitches\" or \"hos\" in derogatory and sexually-misogynist lyrics often assigned to black women arguably may escalate forms of gender-based violence and anti-black misogyny or \"misogynoir.\" The multiplatinum sales of \"The Chronic\" by Dr. Dre featuring Snoop Doggy Dogg in 1992 offers an example typical of the lyrics in the genre. In 1999, scholar Anthony M. Giovacchini wrote about the song in the journal \"Poverty and Prejudice: Media and Race\" (1999):\"Nuthin' but a 'G' Thang\" reads:\n",
"The subject matter inherent in gangsta rap more generally has caused controversy. The White House administrations of both George Bush senior and Bill Clinton criticized the genre. \"The reason why rap is under attack is because it exposes all the contradictions of American culture ...What started out as an underground art form has become a vehicle to expose a lot of critical issues that are not usually discussed in American politics. The problem here is that the White House and wanna-bes like Bill Clinton represent a political system that never intends to deal with inner city urban chaos,\" Sister Souljah told \"The Times\". Due to the influence of Ice T and N.W.A, gangsta rap is often viewed as an originally West Coast phenomenon, despite the contributions of East Coast acts like Boogie Down Productions in shaping the genre.\n",
"Many critics feel that the album's lyrics glamorize gang violence. \"The Washington Post\" writer David Mills wrote: \"The hard-core street rappers defend their violent lyrics as a reflection of 'reality'. But for all the gunshots they mix into their music, rappers rarely try to dramatize that reality — a young man flat on the ground, a knot of lead in his chest, pleading as death slowly takes him in. It's easier for them to imagine themselves pulling the trigger\". However, \"Wichita Eagle-Beacon\" editor Bud Norman noted that \"They N.W.A don't make it sound like much fun ... They describe it with the same nonjudgmental resignation that a Kansan might use about a tornado.\"\n",
"The lyrical themes of rap rock vary. According to Allmusic, \"most rap-metal bands during the mid- to late '90s blended an ultra-aggressive, testosterone-heavy theatricality with either juvenile humor or an introspective angst learned through alternative metal\". However, as the genre began to become more established, several bands branched out into political or social commentary in their lyrics, most notably Rage Against the Machine and Senser which distinguished them from less politically concerned bands such as Linkin Park and Limp Bizkit.\n",
"The explicit nature of gangsta rap's lyrics has made it heavily controversial. There is also debate about the causation between gangsta rap and violent behavior. A study by the Prevention Research Center of the Pacific Institute for Research and Evaluation in Berkeley, Calif., finds young people who listen to rap and hip-hop are more likely to abuse alcohol and commit violent acts.\n",
"As a result, lyrics of rap songs have often been treated as \"confessions\" to a number of violent crimes in the United States. It is also considered to be the duty of rappers and other hip hop artists (DJs, dancers) to \"represent\" their city and neighborhood. This demands being proud of being from disadvantaged cities neighborhoods that have traditionally been a source of shame, and glorifying them in lyrics and graffiti. This has potentially been one of the ways that hip hop has become regarded as a \"local\" rather than \"foreign\" genre of music in so many countries around the world in just a few decades. Nevertheless, sampling and borrowing from a number of genres and places is also a part of the hip hop milieu, and an album like the surprise hit \"Kala\" by Anglo-Tamil rapper M.I.A. was recorded in locations all across the world and features sounds from a different country on every track.\n",
"The v-rap songs often contain violent lyrics that deal with equally violent means of dispatching criminals, foul language and war chants from the \"milícias\" themselves. The musical style closely resembles that of funk carioca.\n"
] |
How do astronomers turn observations of a celestial object (eg. Halley's comet) into solid information about its position, size, orbit, etc, and be able to predict it's behaviour in the future? | Wow this a huge question so i'll try to keep my answer short and simple:
The position of bodies on the solar system are determined using either radar (for big bodies) or the parallax method for smaller ones:
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The orbit is extremely notorious to calculate, you need to fit the position points of the comet in a model and try to simulate the orbit that fit best, with enough points only one will.
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The size is also difficult to obtain, you can use radar or a large number of observations from different locations on earth to try to constraint the size. An easy case is binary bodies, where their speed of rotation will inform you on their mass, so if you know it density you can get an approximation about its size.
| [
"In order to determine the unknown orbit of a body, some observations of its motion with time are required. In early modern astronomy, the only available observational data for celestial objects were the right ascension and declination, obtained by observing the body as it moved in its observation arc, relative to the fixed stars, using an optical telescope. This corresponds to knowing the object's relative direction in space, measured from the observer, but without knowledge of the distance of the object, i.e. the resultant measurement contains only direction information, like a unit vector.\n",
"Astronomers use astrometric techniques for the tracking of near-Earth objects. Astrometry is responsible for the detection of many record-breaking Solar System objects. To find such objects astrometrically, astronomers use telescopes to survey the sky and large-area cameras to take pictures at various determined intervals. By studying these images, they can detect Solar System objects by their movements relative to the background stars, which remain fixed. Once a movement per unit time is observed, astronomers compensate for the parallax caused by Earth's motion during this time and the heliocentric distance to this object is calculated. Using this distance and other photographs, more information about the object, including its orbital elements, can be obtained.\n",
"If the position and velocity relative to the observer are available (as is the case with radar observations), these observational data can be adjusted by the known position and velocity of the observer relative to the attracting body at the times of observation. This yields the position and velocity with respect to the attracting body. If two such observations are available, along with the time difference between them, the orbit can be determined using Lambert's method, invented in the 18th century. See Lambert's problem for details.\n",
"As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may be used to determine the orientation (or attitude) of the spacecraft with respect to the stars. In order to do this, the star tracker must obtain an image of the stars, measure their apparent position in the reference frame of the spacecraft, and identify the stars so their position can be compared with their known absolute position from a star catalog. A star tracker may include a processor to identify stars by comparing the pattern of observed stars with the known pattern of stars in the sky.\n",
"The disks of most stars are much too small in angular size to be observed with current ground-based optical telescopes, and so interferometer telescopes are required to produce images of these objects. Another technique for measuring the angular size of stars is through occultation. By precisely measuring the drop in brightness of a star as it is occulted by the Moon (or the rise in brightness when it reappears), the star's angular diameter can be computed.\n",
"To find a celestial object in a telescope equipped with a DSC computer, one does not need to look up the specific RA and Dec coordinates in a book or other resource, and then adjust the telescope to those numerical readings. Rather, the object is chosen from the electronic database, which causes distance values and arrow markers to appear in the display that indicate the distance and direction to move the telescope. The telescope is moved until the two angular distance values reach zero, indicating that the telescope is properly aligned. When both the RA and Dec axes are thus \"zeroed out\", the object should be in the eyepiece. Many DSCs, like go-to systems, can also work in conjunction with laptop sky programs.\n",
"When making observations, scientists look through telescopes, study images on electronic screens, record meter readings, and so on. Generally, on a basic level, they can agree on what they see, e.g., the thermometer shows 37.9 degrees C. But, if these scientists have different ideas about the theories that have been developed to explain these basic observations, they may disagree about what they are observing. For example, before Albert Einstein's general theory of relativity, observers would have likely interpreted an image of the Einstein cross as five different objects in space. In light of that theory, however, astronomers will tell you that there are actually only two objects, one in the center and four different images of a second object around the sides. Alternatively, if other scientists suspect that something is wrong with the telescope and only one object is actually being observed, they are operating under yet another theory. Observations that cannot be separated from theoretical interpretation are said to be theory-laden.\n"
] |
What causes the two big population spikes in China's population pyramid? | I believe the first "spike" was due to (a) the great leap forward in the early 1960s which killed a lot of people, and (b) decreased birth rates starting around 1970 due to a two-child policy and then one-child policy. Basically, starting in the mid 1960s, birth rates dropped. Consider also decreases in mortality, especially [infant mortality](_URL_0_), in the 1960s and 1970s, which tends to shift the spike later.
The second is an "echo" of the first spike. There were more young adults entering breeding age around 1990 compared to 1980 or 2000, due to the earlier spike.
| [
"We can see how population pyramids change shape according to the country’s specific stage by using the demographic transition model (DTM). By looking at Taiwan’s population pyramid, the country is in stage 4 of the DTM and its shape contracts but it will soon enter stage 5. In stage 5 of the DTM, death rate gradually exceed fertility rate and a country starts to experience overall population loss. Access to great medical care increase the lifespan of people. Knowledge and access to contraception along with the fact most women are in work force cause the sharp decline of the fertility rate.\n",
"One way to visualize population change is to examine population pyramids. These display graphically how many people of each gender there are in each age bracket in a given population. (A pyramid with a wider base and a smaller top, thus a triangle shape, shows rapid population growth, while a more rectangular shape shows a more stable population.) Many countries have differently-shaped population pyramids, due to the factors discussed above, mainly historically different birth and death rates, and in some cases forced changes in population such as war, ethnic cleansing and genocide. Examples of population pyramids by year can be found here.\n",
"China is the largest country by population in the world, being home to some 1.4 billion people. China is expected to witness a zero population growth rate by 2030. China's population growth has slowed since the beginning of this century. This was mostly the result of China's economic growth and increasing living standards which led to the decline. However, many demographers also credit China's family planning policy, which was formulated in the early 1970s, encourages late marriages, late childbearing, and the use of contraceptives, and since 1980 has limited most urban couples to one child and most rural couples to two children. According to government projections, the work-age population will then drop to 870 million. It was said, in 2009, that the Chinese government was hoping to see zero population growth in the future but, in November 2013, a relaxation of the one-child policy was announced amid unpopularity, reduced labour pool and support for an ageing population.\n",
"The High-Level Equilibrium Trap. High population, although sometimes it can be a cheap source of labor which is necessary for economic development, sometimes the high population can be a great setback when it comes to development. The land which a factor of production can be negatively affected by high population. The ration of man to land will eventually decrease as the population of a community grows. During the thirteenth century, China was significantly affected by this population factor when it came to the point of ignition of an industrial revolution. As Lin (1995) puts forward, initially, the culture of the Chinese has valued the males in the society; as a result, early marriages were experienced which boosted the fertility rates leading to the rapid increase in the China population. (p.271). An increase in population with no equivalent increase in economic and technological development will ultimately suppress the available resources causing laxity to the general economic development. The high population experienced in China significantly raised the man to land ratio. The China population was massive. Just as Lin (1995) elaborates, the raising man-land-ratio in the Chinese meant that there was a diminishing surplus per capita. Due to this, China were not able to have surplus resources which can be tapped and used to ignite the industrial revolution. The impact of the high population just as demonstrated by Venn (2005), made china to experience lower real wages as compared to Europe thus it was not vital for China to develop a labour saving devices. The issue of the rising man to land ratio was a great setback for China to start a full-fledged industrial revolution. By the time China was battling with the ever-growing population, Europeans on the other side were enjoying a favorable and optimum population. Just as Lin (1995) puts forward, Europeans were enjoying an optimum man to land ratio with no land strain. The Europeans also had vast unexploited technologies as well as economics possibilities. All these advantages were possible because of the feudal system that the European had embraced, (p. 272). The availability of unexploited ventures made European have significant potential in the execution of a fully-fledged industrial revolution. Lin (1995) further adds that although Europe was lagging behind China during the pre-modern era in terms of economic and technological advancements, the right time finally came for Europe to use the accumulated sufficient knowledge. A strong need to save labor was finally felt in Europe. The agrarian revolution experienced before also provided agricultural surplus that ultimately served as the core assets towards financing the industrial revolution. (p. 272). The accumulation of adequate labor and knowledge to their threshold was a significant step that the European embraced to ignite an industrial revolution. It is also clear that the agrarian revolution experienced in Europe was a tangible asset towards industrialization. The issue of the abundance of land was also at the forefront in ensuring that industrial revolution was realized in Europe contrary to what was experienced in China whereby the large populations put a lot of strain to the available resources as a result making industrial revolution unattainable in China during the early fourteenth century.\n",
"Population growth that exceeds the carrying capacity of an area or environment results in overpopulation. Virginia Abernethy notes that immigration is a road that provides a \"relief valve\" to overpopulation that stops a population from addressing the consequences of its overpopulation and that exports this overpopulation to another location or country. Overpopulation and its consequences is a bigger issue in developing countries.\n",
"Zero population growth is often a goal of demographic planners and environmentalists who believe that reducing population growth is essential for the health of the ecosystem. Preserving cultural traditions and ethnic diversity is a factor for not allowing human populations levels or rates to fall too low. Achieving ZPG is difficult because a country's population growth is often determined by economic factors, incidence of poverty, natural disasters, disease, etc.\n",
"During 1960-2015, the population grew to nearly 1.4 billion. Under Mao Zedong, China nearly doubled in population from 540 million in 1949 to 969 million in 1979. This growth slowed because of the one-child policy instituted in 1979. \n"
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why aren't red pandas and other cute/exotic animals bred as pets? | Not every cute animal would make a good pet, relatively few species out there can thrive while domesticated like cats, dogs, etc.
Many will never be tame, or may need a lot of space to be happy, or cannot be house trained, etc. You can try to breed pet-like qualities, but it won't necessarily be successful. Besides, if you are trying to save a endangered species, is breeding out all their wild qualities really saving them? Certainly we aren't okay with wolves dying out just because we have domesticated dogs. | [
"Due to CITES, this zoo harvest has decreased substantially in recent years, but poaching continues, and red pandas are often sold to private collectors at exorbitant prices. In some parts of Nepal and India, red pandas are kept as pets.\n",
"Red pandas are excellent climbers, and forage largely in trees. They eat mostly bamboo, and may eat small mammals, birds, eggs, flowers, and berries. In captivity, they were observed to eat birds, flowers, maple and mulberry leaves, and bark and fruits of maple, beech, and mulberry.\n",
"The most often cited example of keeping red pandas as pets is the case of former Indian prime minister Indira Gandhi. Pandas were presented to her family as a gift, and they were then housed in \"a special tree house\".\n",
"As of 2019, there are 27 zoos in 21 countries (Australia, Austria, Belgium, Canada, China (Hong Kong), Denmark, Finland, France, Germany, Indonesia, Japan, Malaysia, Mexico, the Netherlands, Singapore, South Korea, Spain, Russia, Taiwan, Thailand, , and United States) that have giant pandas. These zoos have contracts with China to house these pandas for a few years. Giant pandas are on the IUCN Red List so part of the reason these contracts exist between China and international zoos is to try to help the species reproduce before they are brought back to their native land. For this reason, pandas are treated very well.\n",
"For instance, in China reintroduction of captive Giant Pandas have had mixed effects. The initial pandas released from captivity all died quickly after reintroduction. Even now that they have improved their ability to reintroduce pandas, concern remains over how well they captive bred pandas will fare with their wild relatives.\n",
"The red panda (\"Ailurus fulgens\") is a mammal native to the eastern Himalayas and southwestern China. It is listed as Endangered on the IUCN Red List because the wild population is estimated at fewer than 10,000 mature individuals and continues to decline due to habitat loss and fragmentation, poaching, and inbreeding depression.\n",
"Hybridisation with fancy guppy strains (selectively bred \"P. reticulata\") often produces bright and colourful offspring. This has lead to some hybrids being selectively bred themselves and have become so common that they may be sold under any number of names such as peacock, snake, tiger, paradise, fancy, or sword Endler and sometimes as flame tail.\n"
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Kilogram or Newton? | Because if you make the distinction between mass and weight while on the Earth, you're being a dick. | [
"It has long been an objective in metrology to define the kilogram in terms of a fundamental constant, in the same way that the metre is now defined in terms of the speed of light. The 21st General Conference on Weights and Measures (CGPM, 1999) placed these efforts on an official footing, and recommended \"that national laboratories continue their efforts to refine experiments that link the unit of mass to fundamental or atomic constants with a view to a future redefinition of the kilogram.\" Two possibilities attracted particular attention: the Planck constant and the Avogadro constant.\n",
"The definition of the kilogram changed fundamentally; the previous definition defined the kilogram as the mass of the international prototype kilogram, which is an artefact rather than a constant of nature. The new definition relates the kilogram to, amongst things, the equivalent mass of the energy of a photon given its frequency, via the Planck constant.\n",
"The International Prototype of the Kilogram (referred to by metrologists as the IPK) is an object that was used to define the magnitude of the mass of the kilogram from 1889, when it replaced the Kilogramme des Archives, until 2019, when it was replaced by a new definition of the Kilogram based on physical constants. The IPK and its duplicates remain secondary standards for the kilogram and are used to calibrate all other kilogram mass standards on Earth. \n",
"The principle of the electronic kilogram relies on the newly agreed-upon value of the Planck constant similar to the metre being defined by the speed of light. In this case, the electric current and the potential difference are measured in SI units, and the Kibble balance becomes an instrument to measure mass:\n",
"The gal (symbol: Gal), sometimes called galileo after Galileo Galilei, is a unit of acceleration used extensively in the science of gravimetry. The gal is defined as 1 centimeter per second squared (1 cm/s). The milligal (mGal) and microgal (µGal) refer respectively to one thousandth and one millionth of a gal.\n",
"In SI units, the unit is converted to the SI derived unit pascal (Pa), which is defined as one newton per square metre (N/m). A newton is equal to a kg·m/s, and a kilogram-force is 9.80665 newtons, meaning that 1 kgf/cm equals 98.0665 kilopascals (kPa).\n",
"BULLET::::- 2019 definition: The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant to be when expressed in the unit J⋅s, which is equal to kg⋅m⋅s, where the metre and the second are defined in terms of and .\n"
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how do drag racers get grip at the beginning of a race by spinning tires? | They burn out to heat up their tires and soften the rubber to make it more sticky. When they race they carefully control the throttle and clutch so that they are right at the edge of breaking their tires loose into a burnout but not quite. If they accidentally do burn out during a race they will lose unless their competitor makes a worse mistake | [
"Drag racing is a point-to-point race that forces a player to use a manual transmission. Steering in this mode is simplified to simply allow for lane changes, while the game handles the steering along the lanes, and the player focuses more on maintaining an optimum speed for the car. The Nitrous Oxide meter is enlarged and displayed on the left side of the screen.\n",
"Drag is a mode where 2–4 players line up in a quarter or a half mile strip to smoke some rubber and see who is the fastest racer. You have to shift manually in Drag mode, as it requires shifting at the right RPM to gain a faster run. Drag mode also features a different engine damage system, compared to other modes, which makes the engine blow up from improper shifting. A drag race session can involve multiple heat runs, and the player with the best set of heats wins.\n",
"BULLET::::- Shutdown Area: In drag racing, it is the extra 440 yards from the finish line, to the sand trap, used to safely shut down the car, and turn it off the track, so the next racers can begin their race.\n",
"Drag racing or sprints is a racing venue where two participants line up at a dragstrip with a signaled starting line. Upon the starting signal, the riders accelerate down a straight, quarter-mile long paved track where their elapsed time and terminal speed are recorded. The rider to reach the finish line first is the winner. This can occur upon purpose built venues (e.g., Santa Pod), temporary venues (e.g., runways or drives of country houses). In addition to \"regular\" motorcycles, top fuel motorcycles using Nitrous Oxide also compete in this category.\n",
"Drag racing is a motorsport often run using cars with manual transmissions. Manual transmissions allow drivers to control the amount of power transferred from the engine to the wheels by manipulating both clutch and throttle inputs, allowing vehicles to accelerate quickly without losing traction. However, launching a vehicle requires simultaneous gas pedal and clutch pedal inputs, preventing drivers from manipulating the brakes with their feet. Without brake input, drivers staging their vehicle at the starting line would roll if the clutch was slightly engaged. If the driver's vehicle rolled across the staging line before the start of a drag race, the driver could \"red light\" and would disqualify them from that race, nullifying the results or being declared DNF (\"Did Not Finish\"). The line lock prevents vehicles from rolling by allowing the driver to control the clutch and accelerator using foot input and braking with the hand. In an automatic transmission vehicle, a line lock allows the engine to rev up to its peak power RPM and launch aggressively from the starting line.\n",
"A dragstrip is a straight, purpose-built racetrack, typically an eighth, ten feet longer than three-sixteenths, or a quarter of a mile long (660/1,000/1320 feet, 201/304.8/402 metres), with an additional \"shutdown area\" to allow vehicles room to stop after crossing the finish line. Common features also include a 'water box' where vehicles and motorcycles start their burn-outs to clean and heat up their tires to improve traction. There is a set of lights known as a 'Christmas Tree' that counts down to the start. There are also return lanes for the vehicles to return from the end of the track to the pit area.\n",
"Motorcycle drag racing (also known as \"sprints\") involves two participants lining up at a dragstrip with a signaled starting line. Upon the starting signal, the riders accelerate down a long, two lane, straight paved track where their elapsed time and terminal speed are recorded. The rider to reach the finish line first is the winner. The best-known form of motorcycle drag racing is the Pro Stock Bike category, although several other categories exist, including nitromethane engine.\n"
] |
how come being outside in 90 degree weather is uncomfortable, but 90 degree water is amazing...65 degree weather is very comfortable, but 65 degree water is awful? | The thing is, your body doesn't really measure temperature - it measures a little something known as heat flux.
Heat flux is pretty much the rate at which heat enters or leaves your body. For us, the most comfortable state is when we have a little bit of heat leaving our body.
In all of these cases, heat is moving from the body to the surrounding environment, since your body is always warmer, but the important part here is the rate. Different materials touching have different willingness to transfer heat to each other, as it turns out, water transfers heat easier than air does. The farther the temperatures between the two materials is, the faster the heat transfer will occur as well.
So, 90 degree air is uncomfortable because your body wants to move more heat from your body to the surrounding environment, but water, which conducts heat better, will transfer the heat from your body to it much faster, making it a comfortable feeling.
The opposite is true. 65 degree air pulls quite a bit of heat from you, but still it is within normal comfortable range. Water on the other hand will pull much more heat from you, making it cold. | [
"In addition to long distances and elevation, the temperature can play a major factor. At the start in Badwater, temperatures can routinely be as high as degrees, but the temperature quickly drops at higher altitudes. Below freezing temperatures can be encountered near the Portal at night, making temperature swings of over degrees possible in a single day.\n",
"(Illustrated by a still lake, where the surface water can be comfortably warm for swimming but deeper layers be so cold as to represent a danger to swimmers, the same effect as gives rise to notices in London's city docks warning 'Danger Cold Deep Water).\n",
"Temperature extremes are moderated by the adjacent Puget Sound, greater Pacific Ocean, and Lake Washington. Thus extreme heat waves are rare in the Seattle area, as are very cold temperatures (below about ). The Seattle area is the most cloudy region of the United States, due in part to frequent storms and lows moving in from the adjacent Pacific Ocean. Despite having a reputation for frequent rain, Seattle receives less precipitation than many other U.S. cities like Chicago or New York City. However, unlike many other U.S. cities, Seattle has many more \"rain days\", when a very light drizzle falls from the sky for many days.\n",
"In cold climates, the outdoor temperature causes lower capacity for water vapor to flow about. Thus although it may be snowing and the relative humidity outdoors is high, once that air comes into a building and heats up, its new relative humidity is very low, making the air very dry, which can cause discomfort.\n",
"Due to the increasing potential for a higher water vapor partial pressure at higher air temperatures, the water content of air at sea level can get as high as 3% by mass at 30 °C (86 °F) compared to no more than about 0.5% by mass at 0 °C (32 °F). This explains the low levels (in the absence of measures to add moisture) of humidity in heated structures during winter, resulting in dry skin, itchy eyes, and persistence of static electric charges. Even with saturation (100% relative humidity) outdoors, heating of infiltrated outside air that comes indoors raises its moisture capacity, which lowers relative humidity and increases evaporation rates from moist surfaces indoors (including human bodies and household plants.)\n",
"If weather is a concern as a traveler, the best time to visit this city would be towards the start of the dry season where the climate is only beginning to get warm, and precipitation from the wet season has decreased. The dry season can get quite hot and sometimes become uncomfortable for those who are not accustomed to such dry heat.\n",
"People inhabiting tropical and subtropical climates acclimatize somewhat to higher dew points. Thus, a resident of Singapore or Miami, for example, might have a higher threshold for discomfort than a resident of a temperate climate like London or Chicago. People accustomed to temperate climates often begin to feel uncomfortable when the dew point gets above , while others might find dew points up to comfortable. Most inhabitants of temperate areas will consider dew points above oppressive and tropical-like, while inhabitants of hot and humid areas may not find this uncomfortable. Thermal comfort depends not just on physical environmental factors, but also on psychological factors.\n"
] |
Would matter-antimatter annihilation be any different than nuclear explosion? | The annihilation reaction is much "cleaner" as all the reactants form photons with the same energy. There would be a large flash of almost monochromatic gamma radiation. A nuclear reaction leaves free neutrons and radioactive nuclei flying around. The dust, clouds, etc would depend on the environment that the bomb was detonated in. | [
"The paramount advantage of such a theoretical weapon is that antimatter and matter collisions result in the entire sum of their mass energy equivalent being released as energy, which is at least an order of magnitude greater than the energy release of the most efficient fusion weapons (100% vs 7-10%). Annihilation requires and converts exactly equal masses of antimatter and matter by the collision which releases the entire mass-energy of both, which for 1 gram is ~1.8×10 joules. Using the convention that 1 kiloton TNT equivalent = 4.184×10 joules (or one trillion calories of energy), one gram of antimatter reacting with one gram of ordinary matter results in 42.96 kilotons-equivalent of energy (though there is considerable \"loss\" by production of neutrinos).\n",
"If matter–antimatter collisions resulted only in photon emission, the entire rest mass of the particles would be converted to kinetic energy. The energy per unit mass () is about 10 orders of magnitude greater than chemical energies, and about 3 orders of magnitude greater than the nuclear potential energy that can be liberated, today, using nuclear fission (about per fission reaction or ), and about 2 orders of magnitude greater than the best possible results expected from fusion (about for the proton–proton chain). The reaction of of antimatter with of matter would produce (180 petajoules) of energy (by the mass–energy equivalence formula, ), or the rough equivalent of 43 megatons of TNT – slightly less than the yield of the 27,000 kg Tsar Bomba, the largest thermonuclear weapon ever detonated.\n",
"BULLET::::- Antimatter in large quantities would have a mechanism to produce power on a scale several magnitudes above the current level of technology. In antimatter-matter collisions, the entire rest mass of the particles is converted to radiant energy. Their energy density (energy released per mass) is about four orders of magnitude greater than that from using nuclear fission, and about two orders of magnitude greater than the best possible yield from fusion. The reaction of 1 kg of anti-matter with 1 kg of matter would produce 1.8×10 J (180 petajoules) of energy. Although antimatter is sometimes proposed as a source of energy, this does not appear feasible. Artificially producing antimatter—according to current understanding of the laws of physics—involves first converting energy into mass, which yields no net energy. Artificially created antimatter is only usable as a medium of energy storage, not as an energy source, unless future technological developments (contrary to the conservation of the baryon number, such as a CP violation in favour of antimatter) allow the conversion of ordinary matter into anti-matter. Theoretically, humans may in the future have the capability to cultivate and harvest a number of naturally occurring sources of antimatter.\n",
"One hypothesis involves burning antimatter in a stellar core; this hypothesis holds that massive stars become so hot in their cores that energy is converted into matter and antimatter, causing the star to become extremely unstable, and undergo repeated bright eruptions over periods of years. Antimatter in contact with matter would cause an explosion that blows off the outer layers of the star and leaves the core intact; this process can repeat over decades before the large final explosion and collapse to a black hole.\n",
"Speculating that production and storage of antimatter should become feasible, two further issues need to be considered. First, in the annihilation of antimatter, much of the energy is lost as high-energy gamma radiation, and especially also as neutrinos, so that only about 40% of \"mc\" would actually be available if the antimatter were simply allowed to annihilate into radiations thermally. Even so, the energy available for propulsion would be substantially higher than the ~1% of \"mc\" yield of nuclear fusion, the next-best rival candidate.\n",
"The difficulty of preventing accidental detonation of an antimatter weapon may be contrasted with that of a nuclear weapon. Whereas nuclear weapons are 'fail-safe', antimatter weapons are inherently 'fail-deadly': In an antimatter weapon, any failure of containment would immediately result in annihilation, which would damage or destroy the containment system and lead to the release of all of the antimatter material, causing the weapon to detonate entirely at full yield. By contrast, a modern nuclear weapon will explode with a significant yield if (and only if) the nuclear trigger is fired with absolute precision resulting in a neutron source wholly releasing promptly ( microseconds). In short, an antimatter weapon must be actively kept from detonating; whereas a nuclear weapon will not unless deliberately made to do so.\n",
"As shown on the series, the streams of matter (deuterium gas) and antimatter (anti-deuterium) directed into crystallized dilithium are unbalanced: there is usually much more matter in the stream than antimatter. The energy generated in the annihilation reaction heats up the excess deuterium gas, producing a plasma that is used to power the warp nacelles thus allowing a starship to travel faster than light. In addition, most starships use this plasma as a power source for the ship's systems; in the series \"\" (2001–2005), this was referred to as an \"electro-plasma system\", (a backronym of the term \"EPS\", which was used in all other series except ) to refer to a ship's or station's power system. The specific details of this reaction were officially established in the \"\" (1987–1994) series and technical manual; in earlier works it is not clearly defined.\n"
] |
Why aren't small invasive species collapsing ecosystems? | They do.
For some reason invasion of tiny unmentionnables is just not that sexy a topic in journalism and it usually slides under the radar.
Yet there are huge problems with (for instance) [the introduction of earthworms to northeast N America](_URL_1_), or [the uncontrolled expansion of the Mountain Pine Beetle](_URL_0_) to name a few. | [
"Invasive species are a worldwide epidemic threatening ecosystems and costing billions of dollars to control. The reason these invasive species thrive in these locations is due to no predators to hunt them. With no predators, they are able to grow in population quickly but they are taking up too many of the resources in the location they settle in. Invasive species oftentimes destroy the environment which harms the other plants and animals who also share this environment. These various species can also hurt the economy in the long run as we see with the Water hyacinth plant.\n",
"Barriers such as large rivers, seas, oceans, mountains and deserts encourage diversity by enabling independent evolution on either side of the barrier, via the process of allopatric speciation. The term invasive species is applied to species that breach the natural barriers that would normally keep them constrained. Without barriers, such species occupy new territory, often supplanting native species by occupying their niches, or by using resources that would normally sustain native species.\n",
"Alien species, or species that are not native, invade habitats and alter ecosystems around the world. Invasive species are only considered invasive if they are able to survive and sustain themselves in their new environment. A habitat and the environment around it has natural flaws that make them vulnerable to invasive species. The level of vulnerability a habitat is to invasions from outside species is defined as its invasibility. One must be careful not to get this confused with invasiveness, which relates to the species itself and its ability to invade an ecosystem.\n",
"Invasive species can invade both large and small native populations and have a profound effect. Upon invasion, invasive species interbreed with native species to form sterile or more evolutionarily fit hybrids that can outcompete the native populations. Invasive species can cause extinctions of small populations on islands that are particularly vulnerable due to their smaller amounts of genetic diversity. In these populations, local adaptations can be disrupted by the introduction of new genes that may not be as suitable for the small island environments. For example, the \"Cercocarpus traskiae\" of the Catalina Island off the coast of California has faced near extinction with only a single population remaining due to the hybridization of its offspring with \"Cercocarpus betuloides.\"\n",
"Invasive species are often overabundant as they outcompete native species for resources such as food and shelter which allows their population to thrive. Other factors influencing population growth include the lack of native predators or the less common presence of the introduced species within native predator habitat.\n",
"Introduced species, which may be invasive species, are often ecosystem engineers. Kudzu, a leguminous plant introduced to the southeast U.S., changes the distribution and number of animal and bird species in the areas it invades. It also crowds out native plant species. The zebra mussel is an ecosystem engineer in North America. By providing refuge from predators, it encourages the growth of freshwater invertebrates through increasing microhabitats. Light penetration into infected lakes also improves the ecosystem, resulting in an increase in algae. In contrast to the benefits some ecosystem engineers can cause, invasive species often have the reverse effect.\n",
"Introduced species are species that are brought over from non native environments, for example from China to Florida. These species oftentimes find that their new environment is perfect for them and begin to grow and breed at extraordinary rates becoming invasive. \"An invasive species is generally defined as a plant, animal or microbe that is found outside of its native range, where it negatively impacts the ecology, economy, or quality of human life. \" With nothing to keep them in check, since there is nothing in the new environment to challenge their boundaries, or that feeds on it, the alien species will continue to take over and sometimes push native plants or animals out of their native environments.\n"
] |
Which civilization in the ancient (latest being Early Middle Ages) world held the highest literacy rate? Were there any authors who weren't scholars in that civilization? | > a stone tablet that had a joke
> gossip-type documents
You might be interested in [graffiti from Pompeii](_URL_0_). Warning, a lot of this is explicit and NSFW!
* *Theophilus, don’t perform oral sex on girls against the city wall like a dog*
* *Weep, you girls. My penis has given you up. Now it penetrates men’s behinds. Goodbye, wondrous femininity*
* *Restituta, take off your tunic, please, and show us your hairy privates*
* *Lovers are like bees in that they live a honeyed life*
* *I screwed the barmaid*
* *If anyone does not believe in Venus, they should gaze at my girlfriend*
* *Secundus likes to screw boys.*
* *I screwed a lot of girls here.*
* *To the one defecating here. Beware of the curse. If you look down on this curse, may you have an angry Jupiter for an enemy.*
* *Gaius Valerius Venustus, soldier of the 1st praetorian cohort, in the century of Rufus, screwer of women*
* *We have wet the bed, host. I confess we have done wrong. If you want to know why, there was no chamber pot*
| [
"Literacy emerged with the development of numeracy and computational devices as early as 8000 BCE. Script developed independently at least five times in human history Mesopotamia, Egypt, the Indus civilization, lowland Mesoamerica, and China.\n",
"But the availability of a technology of literacy to a society is not enough to ensure its widespread diffusion and use. For example, Eric Havelock observed in \"A Preface to Plato\" that after the ancient Greeks invented writing they adopted a scribal culture that lasted for generations. Few people, other than the scribes, considered it necessary to learn to read or write. In other societies, such as ancient Egypt or medieval Europe, literacy has been a domain confined to political and religious elites.\n",
"The early Islamic Empire also had the highest literacy rates among pre-modern societies, alongside the city of classical Athens in the 4th century BC, and later, China after the introduction of printing from the 10th century. One factor for the relatively high literacy rates in the early Islamic Empire was its parent-driven educational marketplace, as the state did not systematically subsidize educational services until the introduction of state funding under Nizam al-Mulk in the 11th century. Another factor was the diffusion of paper from China, which led to an efflorescence of books and written culture in Islamic society; thus papermaking technology transformed Islamic society (and later, the rest of Afro-Eurasia) from an oral to scribal culture, comparable to the later shifts from scribal to typographic culture, and from typographic culture to the Internet. Other factors include the widespread use of paper books in Islamic society (more so than any other previously existing society), the study and memorisation of the Qur'an, flourishing commercial activity and the emergence of the Maktab and Madrasah educational institutions.\n",
"During the Bronze Age, the cultures of the Ancient Near East are known to have had fully developed writing systems, while the marginal territories affected by the Bronze Age, such as Europe, India and China, remained in the stage of proto-writing.\n",
"The early Islamic Empire also had the highest literacy rates among pre-modern societies, alongside the city of classical Athens in the 4th century BC, and later, China after the introduction of printing from the 10th century. One factor for the relatively high literacy rates in the early Islamic Empire was its parent-driven educational marketplace, as the state did not systematically subsidize educational services until the introduction of state funding under Nizam al-Mulk in the 11th century. Another factor was the diffusion of paper from China, which led to an efflorescence of books and written culture in Islamic society, thus papermaking technology transformed Islamic society (and later, the rest of Afro-Eurasia) from an oral to scribal culture, comparable to the later shifts from scribal to typographic culture, and from typographic culture to the Internet. Other factors include the widespread use of paper books in Islamic society (more so than any other previously existing society), the study and memorization of the Qur'an, flourishing commercial activity, and the emergence of the Maktab and Madrasah educational institutions.\n",
"Literacy rates in the Greco-Roman world were seldom more than 20 percent; averaging perhaps not much above 10 percent in the Roman empire, though with wide regional variations, probably never rising above 5 percent in the western provinces. The literate in classical Greece did not much exceed 5 percent of the population.\n",
"By the 13th century, northern and central Italy had become the most literate society in the world. More than one-third of the male population could read in the vernacular (an unprecedented rate since the decline of the Western Roman Empire), as could a small but significant proportion of women.\n"
] |
My grandfather was a German soldier in WWII and I found this map in his old Atlas. | The retreat from Warsaw that's plotted on the map corresponds in time and places to the so called "wandering cauldron of Kielce" of parts of the 342 Infantry Division - more specifically the XXIVth Panzerkorps. "Cauldron battle" is the German term for an encirclement battle - the troops were encircled by the Soviet troops and fought themselves free along Petrikau, Shiraz, Kalisch and Lissa on to Glogau in Germany. These places are all marked on the map in a dashed line, most likely to mark a retreat (opposed to the straight line marking the march to the front to Warschau/Warsaw).
While I haven't been able to pinpoint any more specific units your grandfather may have fought in, I hope this might serve as a first pointer to someone more versed in these matters than me. It's late here and I need to go to bed, but I'll have another look at it tomorrow and try to find out about these battles around Warsaw to further narrow down which unit your grandfather may have belonged to.
Edit: Had another quick glance at the map - the unit your grandpa was in seems to have ended the war near the town of Budweis/Budějovice. (From the location on the map, even though it is not mapped itself. But if you'd draw a triangle between Budweis, Prague and Pilsen, and put it on the map from your grandfather, you'd get approximately the same area that he plotted). The XXIVth Panzerkorps ended the war in this area and was dissolved there, so it seems very likely that your grandfather volunteered/got drafted, trained in Germany and sent to Warsaw where he joined the XXIVth Panzerkorps, fought in the retreating battles of the Eastern front and then saw the end of the war in the Czech Republic. | [
"Ih his memoir of World War I, A S Bullock recalls the night of 24 October 1918 when he was among the reserves helping the Gloucestershire Regiment in a final push against the Germans at Vendegies-sur-Écaillon. He notes that although 'maps were scarce', he managed not only to obtain one but to retain it after the war, complete with mud from the battlefield (and it remains in his family archive at time of writing, 2019).\n",
"BULLET::::- At Deutsche Dienststelle (WASt), military movements of German soldiers of World War II can be traced. Children in search of their German fathers (soldiers, prisoners of Second World War) may find some clues here.\n",
"Winrich Behr (22 January 1918 – 25 April 2011) was a German officer during World War II. He was on the intelligence staff of the Sixth Army during the Stalingrad encirclement. Behr had served Friedrich Paulus, Erwin Rommel, Gunther von Kluge, Walter Model. He was the witness of Model's last hours in Ruhr Pocket.\n",
"His journal provides a firsthand account of what the German 6th Army was experiencing and how they were coping with the situation, without the outside interpretive influence of propaganda and censorship. Although it is limited in information because it only gives the account of one person, it is still one of the few unaltered German accounts to survive World War II.\n",
"BULLET::::- Lee, Cyrus A. \"Soldat: The World War Two German Army Combat Uniform Collector's Guide (Volume V: Uniforms and Insignia of Panzerkorps Grossdeutschland 1939–1945)\" (Pictorial Histories Publishing Company, Missoula, Montana, 1993)\n",
"BULLET::::- Zetterling, Niklas & Frankson, Anders. \"The Korsun Pocket: The Encirclement and Breakout of a German Army in the East, 1944\". Drexel Hill (Philadelphia), Pennsylvania: Casemate Publishers. 2008. .\n",
"Sajer wrote about his experience on the Eastern Front during World War II in his book \"Le soldat oublié\" (1965; \"The Forgotten Soldier\"). He states that he was an inhabitant of Alsace drafted into the German Wehrmacht at age 16, and that he fought in the elite Großdeutschland Division during World War II. The accuracy and authenticity of the book have been disputed by some historians. Some of the details Sajer mentions are incorrect, while other are impossible to verify due to the lack of surviving witnesses and documents.\n"
] |
[Mathematics] Is there a faster way to multiply (large) numbers? | There's two operations in here: multiplication and addition. Addition is considered cheap in that the trivial algorithm runs in linear time, which is optimal. So I won't consider the number of additions needed in what follows (there'll be some linear term).
Your algorithm is the standard long multiplication algorithm, and runs in O(n^(2)) time (n is the number of digits in each number). The exponent (2) can be improved by swapping to a recursive algorithm like follows: if your two numbers are am+b and cm+d (ie. write the numbers as 'two-digit' numbers in base m), then you compute:
1. A = ac
2. C = bd
3. D = (a+b)(c+d)
4. Your result is Am^2 + (D - C - A)m + C
For appropriate choices of m (ie. m ~ 2^(n/2)), this divides an n-digit by n-digit multiplication into 3 (n/2)-digit by (n/2)-digit multiplications, giving a recurrence relation F(n) = 3F(n/2) + O(n), which has bound F(n) = O(n^(log_2{3})). Better recursive algorithms improve this exponent further, but note that for small numbers, the recursive overhead makes all such algorithms slower than the algorithm you gave -- implementations will generally cut off at some number of digits and just do the multiplication your way (this is a standard practice in implementing recursive algorithms).
More complex algorithms exist as well to bring it down to the approximately linearithmic range. However, again due to overhead and the simplicity of the "more obvious" (but asymptotically slower) algorithms, these algorithms are not actual improvements until the numbers are enormous.
Work from this year (see [here](_URL_0_)) improves this to O(n log n) which is conjectured to be optimal for multiplication (the only provable lower bound is the trivial one of Omega(n)).
Edit: Corrected an error pointed out by /u/mfb- | [
"However, if a fast multiplication algorithm is used, one may modify the Euclidean algorithm for improving the complexity, but the computation of a greatest common divisor becomes slower than the multiplication. More precisely, if the multiplication of two integers of bits takes a time of , then the fastest known algorithm for greatest common divisor has a complexity formula_23 This implies that the fastest known algorithm has a complexity of formula_24\n",
"BULLET::::1. Speed. Since multiplication is more expensive than addition, taking the product of a high number of probabilities is often faster if they are represented in log form. (The conversion to log form is expensive, but is only incurred once.) Multiplication arises from calculating the probability that multiple independent events occur: the probability that all independent events of interest occur is the product of all these events' probabilities.\n",
"For multiplication, the most straightforward algorithms used for multiplying numbers by hand (as taught in primary school) require operations, but multiplication algorithms that achieve complexity have been devised, such as the Schönhage–Strassen algorithm, based on fast Fourier transforms, and there are also algorithms with slightly worse complexity but with sometimes superior real-world performance for smaller . The Karatsuba multiplication is such an algorithm.\n",
"For systems that need to multiply numbers in the range of several thousand digits, such as computer algebra systems and bignum libraries, long multiplication is too slow. These systems may employ Karatsuba multiplication, which was discovered in 1960 (published in 1962). The heart of Karatsuba's method lies in the observation that two-digit multiplication can be done with only three rather than the four multiplications classically required. This is an example of what is now called a \"divide and conquer algorithm\". Suppose we want to multiply two 2-digit base-\"m\" numbers: \"x\"\" m + x\" and \"y\"\" m + y\":\n",
"The classical method of multiplying two -digit numbers requires digit multiplications. Multiplication algorithms have been designed that reduce the computation time considerably when multiplying large numbers. Methods based on the discrete Fourier transform reduce the computational complexity to . Recently, the factor has been replaced by a function that increases much slower although it is still not constant (as it can be hoped).\n",
"The fastest known algorithms for the multiplication of very large integers use the polynomial multiplication method outlined above. Integers can be treated as the value of a polynomial evaluated specifically at the number base, with the coefficients of the polynomial corresponding to the digits in that base (ex. formula_254). After polynomial multiplication, a relatively low-complexity carry-propagation step completes the multiplication.\n",
"BULLET::::3. A yet older child may understand that multiplication of larger numbers can be done using a different method, such as long multiplication, or using a calculator. This is a more advanced form of operational understanding because it supports answering a wider range of questions of the same type.\n"
] |
why do our toes taper down in size? | The big toe is a left over from our days as apes. Their feet were shaped more like our modern hands and the big toe functioned like a thumb, allowing us to grip onto branchs to avoid falling. [Human vs Chimp foot](_URL_0_)
Although good in trees, this wasn’t useful when our ancestors switched to standing and walking on two feet. Thus our feet changed shape to reflect their new role, and our toes reduced to what they are today. | [
"In mammals, the growth rate of nails is related to the length of the terminal phalanges (outermost finger bones). Thus, in humans, the nail of the index finger grows faster than that of the little finger; and fingernails grow up to four times faster than toenails.\n",
"The most common digit to become ingrown is the big toe, but ingrowth can occur on any nail. Ingrown nails can be avoided by cutting nails straight across; not along a curve, not too short and no shorter than the flesh around it. Footwear that is too small or too narrow, or with too shallow a \"toe box\", will exacerbate any underlying problem with a toenail. Sharp square corners may be uncomfortable and cause snagging on socks. Proper cutting leaves the leading edge of the nail free of the flesh, precluding it from growing into the toe. Filing of the corner is reasonable. Some nails require cutting of the corners far back to remove edges that dig into the flesh; this is often done as a partial wedge resection by a podiatrist. Ingrown toe nails can be caused by injury, commonly blunt trauma in which the flesh is pressed against the nail causing a small cut that swells. Injury to the nail can cause it to grow abnormally, making it wider or thicker than normal, or even bulged or crooked.\n",
"It is an impressive stunt, much akin to finger-tip push ups, although not as visually obvious, making it difficult to evaluate, as toes are shorter and wider, making the difference between the tips and pads of the toes (as in fingers) far more difficult to discern.\n",
"The metatarsal bones behind the toes vary in relative length. For most feet, a smooth curve can be traced through the joints at the bases of the toes. But in Morton's foot, the line has to bend more sharply to go through the base of the big toe, as shown in the diagram. This is because the first metatarsal, behind the big toe, is short compared to the second metatarsal, next to it. The longer second metatarsal puts the joint at the base of the second toe (the second metatarsal-phalangeal, or MTP, joint) further forward.\n",
"Hapalonychia, is a condition in which the top of a toe or finger nail becomes soft and thin, causing it to bend or break. This condition can manifest as a result of genetic discrepancy and may also occur due to malnutrition and debility. Nails are often a representation of the internal nutritional of health. Although overall well-being is not typically determined by nail health, fissures, breaks and calcium spots are minor indications of inner health. Hapalonychia may also be attributed to myxedema, rheumatoid arthritis, anorexia, bulimia, Hansen's disease, Raynaud phenomenon, oral retinoid therapy, or radiodermatitis.\n",
"Humans usually have five toes on each foot. When more than five toes are present, this is known as polydactyly. Other variants may include syndactyly or arachnodactyly. Forefoot shape, including toe shape, exhibits significant variation among people; these differences can be measured and have been statistically correlated with ethnicity. Such deviations may affect comfort and fit for various shoe types. Research conducted for the U.S. Army indicated that larger feet may still have smaller arches, toe length, and toe-breadth.\n",
"With the exception of the hallux, toe movement is generally governed by action of the flexor digitorum brevis and extensor digitorum brevis muscles. These attach to the sides of the bones, making it impossible to move individual toes independently. Muscles between the toes on their top and bottom also help to abduct and adduct the toes. The hallux and little toe have unique muscles:\n"
] |
if real estate in downtown toronto, (specifically toronto, not the gta in general), is so overvalued, why does the population continue to grow at a relatively consistent pace? | "Overvalued" isn't really a functional concept. In practice, it's just used when something is more expensive than someone wants it to be.
The real estate in any given place is worth as much as someone is willing to pay for it. If the prices are high, it means people are paying a lot of money for it, so that's what it's worth. If the population is growing and the prices are high, it probably means that the area is desirable enough that wealthy people from other places are moving in. | [
"In March 2017, the cost of owning a home in the greater Toronto area had grown 33% in just one year's time, with 19% of that growth occurring in just the two most recent months. Even the less desirable, semi-detached homes have surpassed $1 million in value. Suburbs have seen large price increases as well. Homes that have not seen upgrades in decades are being sold well over asking price. Condominium prices are seeing consistent growth with each passing year, even with a large number of units under construction. Economists are quick to compare the situation to many other historical real estate crises.\n",
"However, Toronto faces problems common to large North American cities, ranging from pollution, to urban sprawl, to the deterioration of infrastructure, racial tension and inequality, increasing levels of violent crime, heavy traffic congestion, poverty and lack of public housing.\n",
"In the past 25 years, Toronto has lost most of its manufacturing capacity, most of it moving to outlying suburbs in the Greater Toronto Area, seeking lower land costs and land for expansion. This is not a new trend; it has been present for over 100 years. Early suburbs, such as West Toronto, developed for industry and were later engulfed by the expansion of the City of Toronto. West Toronto once had a large stock yards, which has moved well north of the city. Much of the older industrial land has been converted into new residential neighbourhoods, supporting loft and condominium development and the industrial concerns have moved further away.\n",
"Toronto is a rapidly growing city with a substantial amount of older infrastructure. According to the Federation of Canadian Municipalities, Toronto needs to increase its capital spending to address congestion, aging sanitation and water systems, repair backlog and other infrastructure shortcomings. of the Toronto's 2012-2021 Capital Budget is financed using debt. The majority of the investment will be in transportation.\n",
"Executives from the Toronto Parking Authority and Giorgio Mammoliti pushed for a deal that would have had the city overpay by approximately $2.6 million for a piece of land in Mammoliti's ward, according to a report to Toronto City Council by law firm Torys LLP. The deal was days from being completed when it fell through largely due to pressure from Filion. Filion repeatedly questioned the cost of the purchase. He also accused Toronto Parking Authority executives of withholding information. According to the report Filion told the TPA's vice president of real estate, Maria Casista, \"I'm calling the cops\". Toronto's auditor general and the Ontario Provincial Police are currently investigating the land deal.\n",
"The regional population of Toronto is expected to reach 7 million people within the next 10 years, up from the current 5.5 million, making it one of the fastest growing metropolitan areas in North America. Over the last couple of decades, traffic volumes has been increasing steadily in the Greater Toronto Area. However, road and transit investments have not kept pace with the growth in demand. Urban sprawl is a major factor: some commuters travel significant distances within the city and the surrounding GTA for employment. Downtown-to-suburb and suburb-suburb commutes have been increasing as well, which existing public transit services are not organized to efficiently accommodate. This contributes to congestion, adding to travel times and causing smog. Congestion in the GTA is estimated to cost the economy between 6 and 11 billion dollars each year. One study found that the average commute time in GTA exceeds that of 19 larger or comparably sized cities. Other studies comparing international cities show that Toronto residents on average spend the most time commuting to work in North America and sixth-most overall in the world. \n",
"Due to rapid urban and suburban expansion in southern Ontario, traffic congestion had been increasing greatly. A 2013 study by the CD Howe Institute determined that it was costing $7.5-11 billion annually for the economy of Toronto alone.\n"
] |
why is buying from small businesses better? | It's not, necessarily. There are both advantages and disadvantages to buying from a small or large business.
Small businesses make up the bulk of businesses, pretty much everywhere. Money that you spend at a small business is much more likely to stay in the community. I.e., if you buy product X from a small, local retailer, then the profit from that sale goes into the small business owner's pocket; if you buy it from Walmart, then the profit goes into the corporation's pocket. The small business owner is more likely to spend their profit locally, in their own community (or on their own business) than would Walmart, which might spend that profit to open a new store a thousand miles away. So buying from small businesses tends to boost the local economy more.
However, small businesses usually have higher costs. They don't have the economy of scale to buy in bulk like a Walmart or Target or Barnes & Noble or Kroger does, so they're paying higher wholesale prices for their goods and that gets passed along as higher retail prices to you, the consumer. That means your dollar typically doesn't go as far when you're buying from a small business as it would when you're buying from a big retail chain. If you show at big retail chains, you can get more goods for the same amount of money, which is (potentially) good for you and potentially good for the _overall_ economy, because your dollars are being "invested" (i.e. spent) more widely in more supply chains.
The reality is that the economy relies on a mix of small and large businesses. | [
"BULLET::::10. Buy what you want, not what someone wants you to buy: A marketplace of tens of thousands of small businesses is the best way to ensure innovation and low prices over the long-term. A multitude of small businesses, each selecting products based not on a national sales plan but on their own interests and the needs of their local customers, guarantees a much broader range of product choices.\n",
"“Small businesses tend to have just one or two key products that they sell to government as their discriminator. And a lot of initial profits go into keeping talent at the company, rather than investing in the next big development. For all of industry, this requirement will force some business decisions to be made. But for these smaller companies, there’s a lot more to consider.\n",
"Although small businesses have close relationships with their existing customers, finding new customers and reaching new markets is a major challenge for small business owners. Small businesses typically find themselves strapped for time to do marketing, as they have to run the day-to-day aspects of the business. To create a continual stream of new business and find new clients and customers, they must work on marketing their business continuously. Low sales (result of poor marketing) is one of the major reasons of small business failure. Common marketing techniques for small business include business networking (e.g., attending Chamber of Commerce events or trade fairs), \"word of mouth\" promotion by existing customers, customer referrals, Yellow pages directories, television, radio, and outdoor ads (e.g., roadside billboards), print ads, and Internet marketing. TV ads can be quite expensive, so they are normally intended to create awareness of a product or service. Another means by which small businesses can advertise is through the use of \"deal of the day\" websites such as Groupon and Living Social. These Internet deals encourage customers to patronize small businesses.\n",
"BULLET::::- The small retailer and the middle man present in the retail industry play a large part in supporting the local economy, since they typically procure goods and services from the area they have their retail shops in. This leads to increased economic activity, and wealth redistribution. With large, efficient retailers, goods are acquired in other regions, hence reducing the local economy.\n",
"BULLET::::- Growth, expansion and gaining a competitive advantage: A business that is capable of differentiating their product from other businesses in the same industry to large extent will be able to reap profits. This can be applied to how smaller businesses can use product innovation to better differentiate their product from others. Product differentiation can be defined as \"A marketing process that showcases the differences between products. Differentiation looks to make a product more attractive by contrasting its unique qualities with other competing products. Successful product differentiation creates a competitive advantage for the seller, as customers view these products as unique or superior.\" Therefore, small businesses that are able to utilize product innovation effectively will be able to expand and grow into larger businesses, while gaining a competitive advantage over its remaining competitors.\n",
"Independence is another advantage of owning a small business. A small business owner does not have to report to a supervisor or manager. In addition, many people desire to make their own decisions, take their own risks, and reap the rewards of their efforts. Small business owners possess the flexibility and freedom to making their own decisions within the constraints imposed by economic and other environmental factors. However, entrepreneurs have to work for very long hours and understand that ultimately their customers are their bosses.\n",
"Many small businesses can be started at a low cost and on a part-time basis, while a person continues a regular job with an employer or provides care for family members in the home. In developing countries, many small businesses are sole-proprietor operations such as selling produce at a market stall or preparing hot food to sell on the street, that provide a small income. In the 2000s, a small business is also well suited to Internet marketing; because, it can easily serve specialized niches, something that would have been more difficult prior to the Internet revolution which began in the late 1990s. Internet marketing gives small businesses the ability to market with smaller budgets. Adapting to change is crucial in business and particularly small business; not being tied to the bureaucratic inertia associated with large corporations, small businesses can respond to changing marketplace demand more quickly. Small business proprietors tend to be in closer personal contact with their customers and clients than large corporations, as small business owners see their customers in person each week.\n"
] |
How many Decibels can kill a human? | This was covered back in 2001 by [The Straight Dope](_URL_0_).
tl;dr - "German physicist Jürgen Altmann, who has written about the physiological effects of high-intensity sound, tells me the threshold for suffocation or embolism following lung rupture is 2.6 to 11 times atmospheric pressure, depending on pulse duration."
Or around 200 decibels to cause lung rupture and presumably embolism due to air blast. The typical [stun grenade](_URL_1_) stays under these levels, at around 160 to 180 decibels.
And no, I don't know what you would need to shatter, melt, or otherwise cause some immediate and theatrical 'instakill' of the human body. I'll leave that to Hollywood.
Let me know if you need additional information. | [
"The official number of recorded deaths is given as 5,573, representing nearly 3% of the area's inhabitants, with a further 1,583 injured. Other estimates of the death toll are in the range 4,000 to 6,000.\n",
"An official with the ministry also confirmed the figure yesterday [Nov. 10, 2006], but later said that the estimated deaths ranged between 100,000 and 150,000. \"The minister was misquoted. He said between 100,000-150,000 people were killed in three-and-a-half years,\" the official said.\n",
"Potassium-40 is the largest source of natural radioactivity in animals including humans. A 70 kg human body contains about 140 grams of potassium, hence about 0.000117 × 140 = 0.0164 grams of K; whose decay produces about 4,300 disintegrations per second (becquerel) continuously throughout the life of the body.\n",
"\"An official with the ministry also confirmed the figure yesterday [Nov. 10, 2006], but later said that the estimated deaths ranged between 100,000 and 150,000. \"The minister was misquoted. He said between 100,000-150,000 people were killed in three-and-a-half years,\" the official said.\"\n",
"An official with the ministry also confirmed the figure yesterday \"[November 10, 2006]\", but later said that the estimated deaths ranged between 100,000 and 150,000. \"The minister was misquoted. He said between 100,000–150,000 people were killed in three-and-a-half years\", the official said.\n",
"It is estimated that the worldwide incidence rate for brain metastases lies around 9% to 17%, based on the region of diagnosis. However, the baseline incidence rate of brain metastases were found to increase with improvements to brain imaging technology. Approximately 5 - 11% of brain metastasis were found to be deadly at 30 days, and 14 - 23% were found to be deadly at three months.\n",
"The official figures state that 58 people were killed and 510 injured, 111 of them seriously. However, some sources state the fatality figure to be much higher, 110 and a recent video documentary puts it at 200.\n"
] |
what does this german sign mean? | > **NATO military bridge classification signs**. Posted near bridges and viaducts and indicates the safe load-carrying capacity of the bridge for military vehicles.
[source](_URL_0_)
[See also](_URL_1_)
To ELY5:
It means that tanks and trucks that are heavier than that number can't cross the bridge or else the bridge might fall down. | [
"Although the sign might initially appear to be in German and uses an approximation of German grammar, it is composed largely of words that are either near-homonyms of English words or (in the cases of the longer words) actual English words that are rendered in a faux-German spelling. As such, the sign is generally comprehensible by many English speakers regardless of whether they have any fluency in German. Much of the humor in these signs was their intentionally incorrect language.\n",
"In Germany, Signed German, known in German as \"Lautsprachbegleitende Gebärden\" or \"Lautbegleitende Gebärden\" (LBG, \"Speech-accompanying signs\"), is a manually coded form of German that uses the signs of German Sign Language. It is used as a bridge to the German language in education, and for simultaneous translation from German, not as a natural form of communication between deaf people.\n",
"The sign looks like a stylised lowercase \"e\" and its shape, ℮, is precisely defined by an EU directive. It must be placed in the same field of vision as the nominal quantity. The sign has been added to the Unicode list of characters at position U+212E.\n",
"The origin of the sign is thought to be the right-hand half ( ┤ ) of the letter H, which was used in some archaic Greek alphabets as while in others it was used for the vowel eta. In medieval and modern script, it takes the form of a closing half moon (reverse C) or a closing single quotation mark:\n",
"A version of the sign, including also the French word \"ou\" (\"or\") was used in its mathematical meaning by Albert Girard in 1626, and the sign in its modern form was used as early as William Oughtred's \"Clavis Mathematicae\" (1631).\n",
"Signs are made up of a combination of different elements from each of the classes of distinctive features: handshape, hand orientation, location and movement. If one of these elements is changed, it can result in a sign with a completely different meaning. Two signs differing in only one element are deemed to be a minimal pair. German Sign Language uses 32 handshapes, of which six are basic handshapes found in all sign languages.\n",
"In American Sign Language the OK gesture represents the number 9 when held in a stationary position with the palm facing away from the signer. This ASL numerical sign is the last in a sequence of single-digit integers where quantities of fingers denote the numbers 1 through 5, and then the thumb touches each finger in turn to denote 6 (pinky finger), 7 (ring finger), 8 (middle finger), and finally 9 (index finger). When shaken from left to right the sign for the number 9 becomes the number 19.\n"
] |
What determines whether the country uses its indigenous language as the main language or a foreign language as the main language? | The Finns always remained in Finland, even when they were under Russian occupation. Similarly when the Swedes owned the land the language never "died out" as such, as it was still spoken by the majority of people - Swedish became Finland's second language however, as the nobility spoke it.
On the other hand, the Americas saw huge swathes of native people dying due to disease and/or conquest, and colonialism took root. The modern nations are mostly based on the colonies that founded them, and so the languages spoken by the colonists have become the main ones, in almost all countries except Paraguay (where Guaraní is still the most spoken language).
The main difference is the fact that Finland was never a colonial nation, that is, it was always in Europe and therefore was never exposed to the difficulties nations that were not European (e.g. Native American peoples) had. Africa is an interesting thing to think about here - although it was colonised to a similar extent to the new world, the native languages remained. People did not die from diseases in the same way that they did across the Atlantic, as traders would already have brought the diseases millennia ago. | [
"BULLET::::- Internationalization: the adoption of a non-indigenous language as a means of wider communication, as an official language or in a particular domain, such as the use of English in India, Singapore, the Philippines, Papua New Guinea, and South Africa.\n",
"Many regions, notably Canada, Australia, India, New Zealand, Pakistan, South Africa, Hong Kong, Malaysia, Brunei, Singapore, Sri Lanka and the Caribbean, have developed their own native varieties of the language, primarily at the spoken and informal written level.\n",
"An official language that is also an indigenous language is called \"endoglossic\", one that is not indigenous is \"exoglossic\". An instance is Nigeria which has three endoglossic official languages. By this the country aims to protect the indigenous languages although at the same time recognising the English language as its lingua franca.\n",
"There can also be people within a country who speak the \"native\" language of a different country, some of whom may be bilingual. Also, an inherited language may evolve and perhaps absorb some of the characteristics or terms of the new area's predominant language. In cases such as these, it becomes even more difficult to identify specific languages. \n",
"The difference between native language (or First language) and heritage language is an important distinction to make. The term \"native language\" tends to be associated with acquisition at a very early age and carries with it the notion that a person will achieve a high amount of fluency and proficiency in this language. Typically, the native language is the dominant language for a speaker and this speaker is expected to have natural understanding of not only linguistic knowledge, but also pragmatic and cultural knowledge, as well as skills such as writing creatively, making jokes, and translating. On the other hand, the term \"heritage language\" is more associated with the language in which proficiency was sacrificed in order to gain proficiency in the dominant language in a particular community. This is not always the case, however, as some speakers of heritage languages have just as much proficiency in that language as in their other language(s).\n",
"The majority of the country's inhabitants (63.2% in 2009) speak an indigenous language as their first language, with Bislama as a second language. As for English and French, they belong to a third circle, in spite of their official status.\n",
"An indigenous language or autochthonous language, is a language that is native to a region and spoken by indigenous people. This language is from a linguistically distinct community that originated in the area. Indigenous languages are not necessarily national languages (but they can be; cf. Aymara, which is an official language of Bolivia) and national languages are not necessarily indigenous to the country.\n"
] |
i hang around my friend who is sick for one day and i get sick, but my dog who lives with me all the time doesn't get sick from me... why is that? | The germs that get humans sick, don't necessarily make other animals sick. That's why malaria doesn't kill mosquitos, and the avian flu was so scary. | [
"Symptoms are not necessarily distinguishable from other kinds of distress. A dog might stand uncomfortably and seem to be in extreme discomfort for no apparent reason. Other possible symptoms include firm distension of the abdomen, weakness, depression, difficulty breathing, hypersalivation, and retching without producing any vomitus (\"non-productive vomiting\"). A high rate of dogs with GDV have cardiac arrhythmias (40 percent in one study). Chronic GDV may occur in dogs, symptoms of which include loss of appetite, vomiting and weight loss.\n",
"While sick in bed, a boy is asked to play a game of Spot the Dog by his mother, whose pictures of landmarks in their home town are very detailed, but lack people. While looking over the picture, the boy seems to end up sucked into the game, because 1) he ends up looking for dogs around town personally; 2) the town seems to be deserted during his search, just like it is in his mother's pictures; and 3) whenever he finds the dogs, they run away faster than normal to their new location. The last page of the story contains a distorted picture of the town, and a chance for the reader to play Spot the Dog.\n",
"I was often asked if he had cancer or AIDS. In fact at 67, he had diabetes, some rheumatism, the odd creaky joint, a healthy capacity to whinge and the usual symptoms connected with smoking and drinking. But by now the horses were gone and the dog had died. He was eating less and drinking more. One night, he fell down the stairs. He was discovered the next morning on the floor by his housekeeper. He was rushed to the local hospital where pneumonia in one lung was treated effectively and efficiently, a fracture near his hip was repaired and he was diagnosed with brain damage. We were to learn he had Korsakoff's syndrome (an alcohol-related condition) and we decided to keep it private.\n",
"Dogs that develop the disease show signs of the illness within 3 to 7 days. The signs may include lethargy, vomiting, fever, and diarrhea (usually bloody). Generally, the first sign of CPV is lethargy. Secondary signs are loss of weight and appetite or diarrhea followed by vomiting. Diarrhea and vomiting result in dehydration that upsets the electrolyte balance and this may affect the dog critically. Secondary infections occur as a result of the weakened immune system. Because the normal intestinal lining is also compromised, blood and protein leak into the intestines leading to anemia and loss of protein, and endotoxins escape into the bloodstream, causing endotoxemia. Dogs have a distinctive odor in the later stages of the infection. The white blood cell level falls, further weakening the dog. Any or all of these factors can lead to shock and death.\n",
"Any medical causes for these symptoms must be ruled out. Medical diagnoses that may contribute to these symptoms include thyroid disorders, Cushing's disease, diabetes, kidney disease, musculoskeletal disease, cancer, liver problems, and sensory loss. Also, behavioral problems in dogs may be factors that influence these symptoms (i.e. lack of housetraining, lack of social interaction, separation anxiety, phobias, aggression and compulsive disorders).\n",
"Dogs with this condition usually vomit in the morning after not eating all night. Treatment is to feed late at night. H2 blockers and antiemetics can also be used. Bilious vomiting syndrome is a diagnosis of exclusion, meaning that the dog is normal otherwise and no other causes of the vomiting have been found.\n",
"Life-threatening signs usually include those due to the degeneration of the nervous system. Dogs that have been infected with distemper tend to suffer a progressive deterioration of mental abilities and motor skills. With time, the dog can develop more severe seizures, paralysis, reduction in sight, and incoordination. These dogs are usually humanely euthanized because of the immense pain and suffering they face.\n"
] |
the eu election results. can't really find a broken down explanation online. | _URL_0_ for an overall result.
Eurosceptics were the first party in important nations such as UK or France, but they overall get around a fifth of the seats in the European Parliament.
Traditional, eurosupporter parties such as EEP or S & D still have over the 50% of the seats together. | [
"The European Union made it clear that they would not recognize the results of the election. All 25 member countries of the EU summoned their ambassadors from Ukraine in order to register a sharp protest against what is seen as election fraud.\n",
"Varying estimates of the elections led to a scandal. On October 11, the representative of the European Union, Catherine Ashton and European Commissioner Stefan Fule, ignored the assessment of the European Parliament, including in its statement the results of the ODIHR. The Commission on Foreign Relations of the EU discussed the report of Arlacchi. During the discussion, representatives of the “green” condemned the report and said that it discredited the European Parliament. The head of the Socialists’ faction in the EU said that the PACE report cannot be considered reliable at all. It later emerged that a number of EU representatives traveled to Azerbaijan unofficially and on the dime of Azerbaijani organizations, which was regarded by the “European Voice” as “stupidity or corruption”, these trips were labeled “electoral tourism”.\n",
"Varying estimates of the elections led to a scandal. On October 11, the representative of the European Union, Catherine Ashton and European Commissioner Stefan Fule, ignored the assessment of the European Parliament, including in its statement the results of the ODIHR. The Commission on Foreign Relations of the EU discussed the report of Arlacchi. During the discussion, representatives of the “green” condemned the report and said that it discredited the European Parliament. The head of the Socialists’ faction in the EU said that the PACE report cannot be considered reliable at all. It later emerged that a number of EU representatives traveled to Azerbaijan unofficially and on the dime of Azerbaijani organizations, which was regarded by the “European Voice” as “stupidity or corruption”, these trips were labeled “electoral tourism”.The US State Department in its turn discredited the observers from the House of Representatives, describing the elections as not meeting international standards, and expressing solidarity with the ODIHR's assessment.\n",
"The European Union, after calling for the suspension of the elections, stated that they would not recognize the results. On 28 May 2018, the Council of the European Union, with its members representing the executive governments of members states including Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden and the United Kingdom, refused to recognize the election results and called for new, democratic elections.\n",
"On Thursday November 23, 2006 the European Union (EU) election observer mission presented its final report. The report was generally positive and defended the official result of the July 2 presidential election saying they \"reflect[ed] the legitimate will of the Mexican people.\" However, the report also expressed concerns and raised several criticisms, both general and specific, of the electoral process and the election. The report includes 48 specific recommendations for future reform to \"strengthen the electoral process\", such as introducing random automatic recounts in the case of a close election, shortening the campaign period, considering the introduction of a two round run-off system for presidential elections, and general clarifications in the electoral law (e.g., clarifying the grounds for requesting a recount and for the annulling of the election).\n",
"On Thursday November 23, 2006 the European Union (EU) election observer mission presented its final report. The report was generally positive and defended the official result of the July 2 presidential election saying they \"reflect[ed] the legitimate will of the Mexican people.\" However, the report also expressed concerns and raised several criticisms, both general and specific, of the electoral process and the election. The report includes 48 specific recommendations for future reform to \"strengthen the electoral process,\" such as introducing random automatic recounts in the case of a close election, shortening the campaign period, considering the introduction of a two round run-off system for presidential elections, and general clarifications in the electoral law (e.g., clarifying the grounds for requesting a recount and for the annulling of the election).\n",
"The United Kingdom's component of the 2019 European Parliament election was held on Thursday 23 May 2019 and the results were announced on Sunday 26 and Monday 27 May 2019, after all the other EU countries had voted.\n"
] |
If the heart is a muscle that needs blood to function how does it and whose blood does it pump at first? | The heart gets its blood supply from two coronary arteries, and their branches. These arteries begin immediately after the aortic valve, the valve that prevents blood from flowing back into the heart from the aorta. It is composed of three leaflets, two of which have the opening to a coronary artery immediately adjacent to them. These arteries then branch and spread out on the surface of the heart.
During systole (contraction) blood flows into the aorta. During diastole it attempts to flow from the aorta back into the heart but the aortic valve snaps shut. Thus there is an increase in pressure on the aortic side of the aortic valve, which drives blood into the coronary arteries. | [
"The heart is typically a muscular tube that runs just under the back and for most of the length of the hemocoel. It contracts in ripples that run from rear to front, pushing blood forwards. Sections not being squeezed by the heart muscle are expanded either by elastic ligaments or by small muscles, in either case connecting the heart to the body wall. Along the heart run a series of paired ostia, non-return valves that allow blood to enter the heart but prevent it from leaving before it reaches the front.\n",
"The heart is a long, tubular organ running the entire length of the body, from the brain to the tip of the abdomen. It has valves within it that prevent blood from flowing the wrong way. The fluids bathing the internal organs is circulated by the heart; these fluids then filter through the organs and tissues. The pharynx, which is part of the gut, controlled by six muscles, pumps food into the oesophagus. Debris in the food, such as soil, is filtered before it enters the oesophagus and is collected in a tiny trap, the infrabuccal pocket. When this pocket becomes full, the \"Acromyrmex\" ant empties it into an area within or outside the nest designated as a waste-products area.\n",
"Cardiac muscle cells or cardiomyocytes are the contracting cells which allow the heart to pump. Each cardiomyocyte needs to contract in coordination with its neighbouring cells - known as a functional syncytium - working to efficiently pump blood from the heart, and if this coordination breaks down then – despite individual cells contracting – the heart may not pump at all, such as may occur during abnormal heart rhythms such as ventricular fibrillation.\n",
"Contracting heart muscle uses a lot of energy, and therefore requires a constant flow of blood to provide oxygen and nutrients. Blood is brought to the myocardium by the coronary arteries. These originate from the aortic root and lie on the outer or epicardial surface of the heart. Blood is then drained away by the coronary veins into the right atrium.\n",
"The heart is a biological pump designed to move blood through the brain and body. It has four chambers: two \"upper\" chambers called the atria, and two \"lower\" chambers called the ventricles. Anatomically, the atria are more posterior to the ventricles, but for ease of understanding, are often drawn \"above\" them. The atria are separated from the ventricles beneath by the atrioventricular valves, which open to allow blood into the ventricles and close when ventricular pressure exceeds atrial pressure. \n",
"The heart pumps blood with a rhythm determined by a group of pacemaking cells in the sinoatrial node. These generate a current that causes contraction of the heart, traveling through the atrioventricular node and along the conduction system of the heart. The heart receives blood low in oxygen from the systemic circulation, which enters the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here it is pumped into the pulmonary circulation, through the lungs where it receives oxygen and gives off carbon dioxide. Oxygenated blood then returns to the left atrium, passes through the left ventricle and is pumped out through the aorta to the systemic circulation−where the oxygen is used and metabolized to carbon dioxide. The heart beats at a resting rate close to 72 beats per minute. Exercise temporarily increases the rate, but lowers resting heart rate in the long term, and is good for heart health.\n",
"The heart is a muscular organ in most animals, which pumps blood through the blood vessels of the circulatory system. Blood provides the body with oxygen and nutrients, as well as assisting in the removal of metabolic wastes. In humans, the heart is located between the lungs, in the middle compartment of the chest.\n"
] |
why can certain electrical items turn on for a split second when they're not plugged in? | I've never been able to see an item turn on when not plugged in, but certain ones I've seen remain on momentarily after being unplugged.
Either way, the answer is the same, capacitors. Capacitors are devices that store small amount of electrical energy. They are kinda like really fast charging/discharging batteries, but they hold a very limited amount of energy. A capacitor is essentially just two metal plates separated by a distance. Charge can't cross the gap, but it can build up on either plate. Capacitors have many, many uses.
Many electronic devices have pretty big capacitors in their power circuit. The wall uses AC power, the device uses DC. To convert you from AC to DC, one of the things you need is a capacitor. The capacitor helps smooth out the DC voltage. When unplugged, the capacitor can supply a limited amount of energy before it drains. | [
"Due to the electromagnet in the contactor, if power to the machine should fail the contactor will automatically disengage. Unlike machines with an ordinary latching switch (such as a common light switch), when the power is resumed the machine will not operate until being turned on again. As a result, magnetic starters often use momentary switches for \"off\" and \"on\" functions, as this type of switch returns to a defined normal position when released. Latching switches do not have this feature and therefore are normally not used with a magnetic starter.\n",
"In reality, it is impossible to have a perfect synchronization between the switches. At one point during the commutation, they would be either both on (thus shorting the voltage source) or off (thus leaving the current source in an open circuit). This is why one of the switches has to be replaced by a diode. A diode is a natural commutation device, i.e. its state is controlled by the circuit itself. It will turn on or off at the exact moment it has to. The consequence of using a diode in a commutation cell is that it makes it unidirectional (see figure 3). A bidirectional cell can be built, but it is basically equivalent to two unidirectional cells connected in parallel.\n",
"The major problem with this method is that in one of the four switch combinations the socket around the bulb is electrified at both of its terminals even though the bulb is not lit. As the shell may be energized, even with the light switched off, this poses a risk of electrical shock when changing the bulb. This method is therefore prohibited in modern building wiring.\n",
"\"Many appliances continue to draw a small amount of power when they are switched off. These \"phantom\" loads occur in most appliances that use electricity, such as VCRs, televisions, stereos, computers, and kitchen appliances. This can be avoided by unplugging the appliance or using a power strip and using the switch on the power strip to cut all power to the appliance.\"\n",
"Another view is that a device plugged into an electrical outlet of a wall becomes part of the building, but is nonfunctional while the switch is off; turning it on would then constitute building (category 35) and turning it off would be demolishing (category 34). Some schools of thought consider the use of electricity to be forbidden only by rabbinic injunction, rather than because it violates one of the original categories.\n",
"The lightpipe is \"hot-pluggable\", which means devices do not need to be turned off for plugging in or unplugging (although it is advisable to mute the receiving equipment, since there will be a large signal spike when the connection is made). \n",
"The mains connectors of the appliance plug are two rounded sockets that accept two rounded pins from the appliance. They are unpolarised. The third connection, earth, is a large metal contact on each side of the plug body which makes contact with the sides of the plug receptacle, grounding the appliance body. Some appliances using these connectors incorporate a spring and plunger mechanism with a temperature-sensitive release system; if the temperature rises significantly above a preset limit - for example, if a kettle boils dry - the spring is released and (if all goes well) the plunger pushes the plug and socket apart. It must then be allowed to cool and reset manually by forcing the connector back into the appliance.\n"
] |
what is a bond and where does that money paid go to? | A bond is a promise to pay someone money at a future date. Governments and business will issue bonds to raise money. Investors give money to the government or business and get the bond in exchange. When the bond matures the government or business will give whoever holds the bond the money that they promised. In between the initial sale and maturity the bond can be bought and sold. | [
"Thus a bond is a form of loan or IOU: the \"holder\" of the bond is the lender (creditor), the \"issuer\" of the bond is the borrower (debtor), and the \"coupon\" is the interest. Bonds provide the borrower with external funds to finance long-term investments, or, in the case of government bonds, to finance current expenditure. Certificates of deposit (CDs) or short-term commercial paper are considered to be money market instruments and not bonds: the main difference is the length of the term of the instrument.\n",
"The bond is a debt security, under which the issuer owes the holders a debt and (depending on the terms of the bond) is obliged to pay them interest (the coupon) or to repay the principal at a later date, termed the maturity date. Interest is usually payable at fixed intervals (semiannual, annual, sometimes monthly). Very often the bond is negotiable, that is, the ownership of the instrument can be transferred in the secondary market. This means that once the transfer agents at the bank medallion stamp the bond, it is highly liquid on the secondary market.\n",
"Bonds are bought and traded mostly by institutions like central banks, sovereign wealth funds, pension funds, insurance companies, hedge funds, and banks. Insurance companies and pension funds have liabilities which essentially include fixed amounts payable on predetermined dates. They buy the bonds to match their liabilities, and may be compelled by law to do this. Most individuals who want to own bonds do so through bond funds. Still, in the U.S., nearly 10% of all bonds outstanding are held directly by households.\n",
"A government bond is a bond issued by a national government. Such bonds are most often denominated in the country's domestic currency. Sovereigns can also issue debt in foreign currencies: almost 70% of all debt in 2000 was denominated in US dollars. Government bonds are sometimes regarded as risk-free bonds, because national governments can if necessary create money de novo to redeem the bond in their own currency at maturity. Although many governments are prohibited by law from creating money directly (that function having been delegated to their central banks), central banks may provide finance by buying government bonds, sometimes referred to as monetizing the debt.\n",
"A company may also issue bonds, which are debt securities. Bonds have a fixed lifetime, usually a number of years; with long-term bonds, lasting over 30 years, being less common. At the end of the bond's life the money should be repaid in full. Interest may be added to the end payment, or can be paid in regular installments (known as coupons) during the life of the bond.\n",
"For a financial instrument such as a bond, interest is calculated and paid in set intervals (for instance annually or semi-annually). Ownership of bonds/loans can be transferred between different investors not just when coupons are paid, but at any time in-between coupons. Accrued interest addresses the problem regarding the ownership of the next coupon if the bond is sold in the period between coupons: Only the current owner can receive the coupon payment, but the investor who sold the bond must be compensated for the period of time for which he or she owned the bond. In other words, the previous owner must be paid the interest that accrued before the sale.\n",
"The bond market is part of the credit market, with bank loans forming the other main component. The global credit market in aggregate is about 3 times the size of the global equity market. Bank loans are not securities under the Securities and Exchange Act, but bonds typically are and are therefore more highly regulated. Bonds are typically not secured by collateral (although they can be), and are sold in relatively small denominations of around $1,000 to $10,000. Unlike bank loans, bonds may be held by retail investors. Bonds are more frequently traded than loans, although not as often as equity.\n"
] |
Is there a limit on the mass of a spaceship built in space? (Due to gravity, etc.?) | The only theoretical limit would be the point at which it becomes a black hole. For a spherical spaceship with radius *r*, the upper limit on mass would be:
m = r*c^(2)/2G
Where *c* is the speed of light and *G* is the Newtonian gravitational constant. | [
"A notable difference between the orbital context of space architecture and Earth-based architecture is that structures in orbit do not need to support their own weight. This is possible because of the microgravity condition of objects in free fall. In fact much space hardware, such as the space shuttle's robotic arm, is designed only to function in orbit and wouldn't be able to lift its own weight on the Earth's surface. Microgravity also allows an astronaut to move an object of practically any mass, albeit slowly, provided he or she is adequately constrained to another object. Therefore, structural considerations for the orbital environment are dramatically different from those of terrestrial buildings, and the biggest challenge to holding a space station together is usually launching and assembling the components intact. Construction on extraterrestrial surfaces still needs to be designed to support its own weight, but its weight will depend on the strength of the local gravitational field.\n",
"While the weight of an object is dependent on the strength of the local gravitational field, the mass of an object is independent of gravity, as mass is a measure of the quantity of matter. Accordingly, for astronauts in microgravity, no effort is required to hold objects off the cabin floor; they are \"weightless\". However, since objects in microgravity still retain their mass and inertia, an astronaut must exert ten times as much force to accelerate a 10kilogram object at the same rate as a 1kilogram object.\n",
"List of heaviest spacecraft is a listing of selected spacecraft by mass. Spacecraft may change mass over time such as by use of propellant. The heaviest artificial objects to reach space include space stations, various upper stages, and discarded Space Shuttle external tanks.\n",
"As with aeronautics, the restrictions of mass, temperatures, and external forces require that applications in space survive extreme conditions: high-grade vacuum, the radiation bombardment of interplanetary space and the magnetic belts of low Earth orbit. Space launch vehicles must withstand titanic forces, while satellites can experience huge variations in temperature in very brief periods. Extreme constraints on mass cause astronautical engineers to face the constant need to save mass in the design in order to maximize the actual payload that reaches orbit.\n",
"While the \"weight\" of an object varies in proportion to the strength of the gravitational field, its \"mass\" is constant, as long as no energy or matter is added to the object. For example, although a satellite in orbit (essentially a free-fall) is \"weightless\", it still retains its mass and inertia. Accordingly, even in orbit, an astronaut trying to accelerate the satellite in any direction is still required to exert force, and needs to exert ten times as much force to accelerate a 10ton satellite at the same rate as one with a mass of only 1 ton.\n",
"Reduction in mass was possible because the Progress was designed to be unmanned and disposable. This means that there is no need for bulky life support systems and heat shields. A small amount of weight is saved due to the lack of automatic rescue crews system and lack of parachutes. The spacecraft also has no ability to split into separate modules. After undocking, the spacecraft performs a retrofire and burns up in the atmosphere.\n",
"The law of conservation of momentum is usually taken to imply that any engine which uses no reaction mass cannot accelerate the center of mass of a spaceship (changing orientation, on the other hand, is possible). But space is not empty, especially space inside the Solar System; there are gravitation fields, magnetic fields, electromagnetic waves, solar wind and solar radiation. Electromagnetic waves in particular are known to contain momentum, despite being massless; specifically the momentum flux density P of an EM wave is quantitatively 1/c^2 times the Poynting vector S, i.e. P = S/c^2, where c is the velocity of light. Field propulsion methods which do not rely on reaction mass thus must try to take advantage of this fact by coupling to a momentum-bearing field such as an EM wave that exists in the vicinity of the craft. However, because many of these phenomena are diffuse in nature, corresponding propulsion structures need to be proportionately large.\n"
] |
If our stomachs churn/mix our food, why don't we feel it moving around? | The stomach isn't innervated with sensory neurons so no feeling, same reason why you don't typically feel any other internal organ doing its job | [
"The vagovagal reflex is active during the receptive relaxation of the stomach in response to swallowing of food (prior to it reaching the stomach). When food enters the stomach a \"vagovagal\" reflex goes from the stomach to the brain, and then back again to the stomach causing active relaxation of the smooth muscle in the stomach wall. If vagal innervation is interrupted then intra-gastric pressure increases. This is a potential cause of vomiting due to the inability of the proximal stomach smooth muscle to undergo receptive relaxation.\n",
"The stomach twists around the longitudinal axis of the digestive tract, also known as \"volvulus\". Gas distension may occur prior to or after the stomach twists. The most common direction for rotation is clockwise, viewing the animal from behind. The stomach can rotate up to 360° in this direction and 90° counterclockwise. If the volvulus is greater than 180°, the esophagus is closed off, thereby preventing the animal from relieving the condition by belching or vomiting. The results of this distortion of normal anatomy and gas distension include hypotension (low blood pressure), decreased return of blood to the heart, ischemia (loss of blood supply) of the stomach, and shock. Pressure on the portal vein decreases blood flow to liver and decreases the ability of that organ to remove toxins and absorbed bacteria from the blood. At the other end of the stomach, the spleen may be damaged if the twisting interrupts its blood supply. If not quickly treated, bloat can lead to blood poisoning, peritonitis and death by toxic shock.\n",
"BULLET::::- Louder rumbles may occur when one is hungry. Around two hours after the stomach has been emptied, it sends signals to the brain, which tells the digestive muscles to restart peristalsis in a wave called the migrating motor complex. Food left behind after the first cycle is swept up, and the vibrations of the empty stomach cause hunger. Appetite plays a big role in this situation. Peristalsis recurs about every hour, and one's appetite may cause 10- to 20-minute food cravings.\n",
"BULLET::::- Satiation occurs when the brain acknowledges that enough food has been eaten; there are triggers in the body that send these signals to the brain. Sizer and Whitney say a, “Greater exposure of the mouth to food triggers increased satiation. When the stomach stretches to accommodate a meal, nerve receptors in the stomach fire, sending a signal to the brain that the stomach is full”. Healthy snacks are ones that leave the body feeling filled so that it does not continue to signal to the brain that it still wants food.\n",
"In much of a digestive tract such as the human gastrointestinal tract, smooth muscle tissue contracts in sequence to produce a peristaltic wave, which propels a ball of food (called a bolus while in the esophagus and upper gastrointestinal tract and chyme in the stomach) along the tract. Peristaltic movement comprises relaxation of circular smooth muscles, then their contraction behind the chewed material to keep it from moving backward, then longitudinal contraction to push it forward.\n",
"After food is chewed into a bolus, it is swallowed and moved through the esophagus. Smooth muscles contract behind the bolus to prevent it from being squeezed back into the mouth. Then rhythmic, unidirectional waves of contractions work to rapidly force the food into the stomach. The migrating motor complex (MMC) helps trigger peristaltic waves. This process works in one direction only and its sole esophageal function is to move food from the mouth into the stomach (the MMC also functions to clear out remaining food in the stomach to the small bowel, and remaining particles in the small bowel into the colon).\n",
"The hypothesis suggests that the air bubble in the stomach stimulates the sensory limb of the reflex at receptors in the stomach, esophagus and along the diaphragm. This triggers the hiccup, which creates suction in the chest, pulling air from the stomach up and out through the mouth, effectively burping the animal.\n"
] |
if someone receives a full organ transplant will the organ be eventually replaced by the host's cells or will it remain as the the donor's cells for the rest of the host's life. | It will always be the donor's cells. It can be possible to wean off of antirejection drugs as your body gets used to the new organ, but if your whole liver is replaced by a donor liver, you do not have any of your own liver cells to replicate and replace the donor cells. | [
"Many societies have a system for organ donation, in which a living or deceased donor's organ is transplanted into a person with a failing organ. The transplantation of larger solid organs often requires immunosuppression to prevent organ rejection or graft-versus-host disease.\n",
"Bone marrow transplant can replace the transplant recipient's immune system with the donor's, and the recipient accepts the new organ without rejection. The marrow's hematopoietic stem cells—the reservoir of stem cells replenishing exhausted blood cells including white blood cells forming the immune system—must be of the individual who donated the organ or of an identical twin or a clone. There is a risk of graft-versus-host disease (GVHD), however, whereby mature lymphocytes entering with marrow recognize the new host tissues as foreign and destroy them.\n",
"Living donor transplantation is a multidisciplinary approach. All living liver donors undergo medical evaluation. Every hospital which performs transplants has dedicated nurses that provide specific information about the procedure and answer questions that families may have. During the evaluation process, confidentiality is assured on the potential donor. Every effort is made to ensure that organ donation is not made by coercion from other family members. The transplant team provides both the donor and family thorough counseling and support which continues until full recovery is made.\n",
"Organ rejection is the unfortunate circumstance of the host immune system recognizing the transplanted organ as foreign. This is the most notable complication facing transplant recipients. Through T-cell receptors, T-lymphocytes are able to distinguish between self and non-self by recognizing human leukocyte antigens (HLA) bound to the major histocompatibility complex (MHC) protein located on the surface of organ cells. Once identified as foreign, the immune system proceeds to destroy the transplanted tissue. The panel reactive antibody (PRA) test measures the proportion of the population to which a recipient will react via pre-existing antibodies to various HLA antigens; in other words, how likely a patient is to acutely reject their new transplant. Therefore, it is essential that HLA and PRA statuses are tested for and demonstrate low immunoreactivity of the patient to the graft. In some cases, a recipient may suffer from graft-versus-host disease, in which cells of the transplanted organ attack the recipient's cells.\n",
"Transplanted tissue is accepted by immunocompetent recipient if it is functional in the absence of immunosuppressive drugs and without histologic signs of rejection. Host can accept another graft from the same donor but reject graft from different donor. \n",
"The Convention provides the general rule that living donors for organ transplants are only to be utilised if there is no availability of organs from a deceased person. Any removed parts of the body must be disposed of respectfully in accordance with the wishes of the individual. In addition, there is to be no financial gain arising from the human body or its parts, however adequate compensation for expenses incurred for a medical procedure is not prohibited. The rules relating to consent laid out in \"Chapter II\" of the Convention also apply in the context of organ transplantation.\n",
"At the same time Qaradawi issued a fatwa (edict) that organ transplant from living to a living person is permissible in Islam but through donation as donation is considered charity. As for a dead person, only when the brain stops, the transplant can then be carried out.\n"
] |
what is the process for getting a job with mi5/mi6/secret service? | For the US Secret Service, candidates must be U.S. citizens and must submit to urinalysis screening for illegal drug use prior to appointment. All Secret Service positions require a Top Secret security clearance. All applicants must undergo a full, Secret Service-specific, Top Secret clearance process regardless of current existing clearance standings; certain positions may also require the applicant to successfully complete a polygraph and/or medical examination. Age, vision and excellent physical condition requirements may also apply.
If you want to be a secret agent and look like you belong in CSI, [this site](_URL_0_) lists the qualifications | [
"The Chief of the Secret Intelligence Service serves as the head of the Secret Intelligence Service (SIS, also commonly known as MI6), which is part of the United Kingdom intelligence community. The Chief is appointed by the Foreign Secretary, to whom he directly reports. Annual reports are also made to the Prime Minister.\n",
"The actual role carried out by an intelligence officer varies depending on the remit of his/her parent organization. Officers of foreign intelligence agencies (e.g. the United States' Central Intelligence Agency, the United Kingdom's Secret Intelligence Service (MI6) and the Australian Secret Intelligence Service (ASIS)) may spend much of their careers abroad. Officers of domestic intelligence agencies (such as the United States' Federal Bureau of Investigation, the UK's Security Service (MI5) and the Australian Security Intelligence Organisation (ASIO)) are responsible for counter-terrorism, counter-espionage, counter-proliferation and the detection and prevention of serious organized crime within their own countries (although, in Britain, the Serious Organised Crime Agency had been set up to take care of serious organized crime).\n",
"The 00 Section of MI6 is considered the elite of the Secret Service. Agents with the 00 prefix have proven themselves capable enough in the field to be entrusted with the licence to kill: the authorisation to, at their own discretion, commit acts of assassination and other controversial activities in order to complete their missions, without having to first seek permission from headquarters.\n",
"The Secret Intelligence Service (SIS), commonly known as MI6, is the foreign intelligence service of the government of the United Kingdom, tasked mainly with the covert overseas collection and analysis of human intelligence (HUMINT) in support of the UK's national security. SIS is a member of the country's intelligence community and its Chief is accountable to the country's Foreign Secretary.\n",
"The organisation supports the work of the Joint Intelligence Committee (tasked with directing the Secret Intelligence Service (MI6), Security Service (MI5) and GCHQ) and National Security Council by providing intelligence assessments to Ministers and senior officials.\n",
"Another method is to directly recruit an intelligence officer (or terrorist member) from within the ranks of the adversary service (terrorist group) and having that officer (terrorist) maintain their normal duties while spying on their parent service (organization); this is also referred to as recruiting an \"agent\" or defector in place.\n",
"Another method is to directly recruit an intelligence officer (or terrorist member) from within the ranks of the adversary service (terrorist group) and having that officer (terrorist) maintain their normal duties while spying on their parent service (organization); this is also referred to as recruiting an “agent” or defector in place.\n"
] |
AskScience AMA Series: I am pfisico and I build instruments to study the cosmic microwave background radiation. Ask Me Anything! | My question is a bit more basic than the other's here. What is, as you see it, the most important, or most exciting, science currently going on that could use your CMB data?
| [
"Arno Penzias and Robert Wilson of Bell Labs used the Holmdel Horn Antenna located on Crawford Hill to take measurements of the cosmic microwave background radiation. They were awarded the 1978 Nobel Prize in Physics for these efforts that supported the Big Bang theory. For more information, see \"Discovery of cosmic microwave background radiation\".\n",
"A major recent focus of microwave radio astronomy has been mapping the cosmic microwave background radiation (CMBR) discovered in 1964 by radio astronomers Arno Penzias and Robert Wilson. This faint background radiation, which fills the universe and is almost the same in all directions, is \"relic radiation\" from the Big Bang, and is one of the few sources of information about conditions in the early universe. Due to the expansion and thus cooling of the Universe, the originally high-energy radiation has been shifted into the microwave region of the radio spectrum. Sufficiently sensitive radio telescopes can detected the CMBR as a faint signal that is not associated with any star, galaxy, or other object.\n",
"The design of cosmic microwave background experiments is a very challenging task. The greatest problems are the receivers, the telescope optics and the atmosphere. Many improved microwave amplifier technologies have been designed for microwave background applications. Some technologies used are HEMT, MMIC, SIS and bolometers. Experiments generally use elaborate cryogenic systems to keep the amplifiers cool. Often, experiments are interferometers which only measure the spatial fluctuations in signals on the sky, and are insensitive to the average 2.7 K background.\n",
"Microwave space telescopes have primarily been used to measure cosmological parameters from the Cosmic Microwave Background. They also measure synchrotron radiation, free-free emission and spinning dust from our Galaxy, as well as extragalactic compact sources and galaxy clusters through the Sunyaev-Zel'dovich effect.\n",
"The Yuan-Tseh Lee Array for Microwave Background Anisotropy, also known as the Array for Microwave Background Anisotropy (AMiBA), is a radio telescope designed to observe the cosmic microwave background and the Sunyaev-Zel'dovich effect in clusters of galaxies.\n",
"Before leading WMAP, Bennett was the Deputy Principal Investigator for the Differential Microwave Radiometers (DMR) instrument on the Cosmic Background Explorer (COBE) mission that discovered the anisotropy of the cosmic microwave background radiation. Bennett led the effort to rebuild the radiometer front-end microwave components that succeeded in significantly enhancing the sensitivity of the DMR instrument. The Cosmic Background Explorer (COBE) Science Team also precisely measured the spectrum of the cosmic microwave background radiation.\n",
"BULLET::::- The Array for Microwave Background Anisotropy (AMiBA) is a radio telescope array designed to observe the cosmic microwave background and the Sunyaev-Zel'dovich effect. It consists of seven receivers on a hexapod mount.\n"
] |
Can you heat a metal until it turns into a gas? If so, does this ever happen or is it just a theoretical state? | Absolutely; mercury vapor lights, some metal plateing processes use vaporizing the plateting material. | [
"Often, the metal's sensitivity to heat must also be considered. Even a relatively routine workshop procedure involving heating is complicated by the fact that aluminium, unlike steel, will melt without first glowing red. Forming operations where a blow torch is used can reverse or remove heat treating, therefore is not advised whatsoever. No visual signs reveal how the material is internally damaged. Much like welding heat treated, high strength link chain, all strength is now lost by heat of the torch. The chain is dangerous and must be discarded.\n",
"When a metal object is placed in a vacuum and is heated to incandescence, the energy is sufficient to cause electrons to \"boil\" away from the surface atoms and surround the metal object in a cloud of free electrons. This is called thermionic emission. The resulting cloud is negatively charged, and can be attracted to any nearby positively charged object, thus producing an electric current which passes through the vacuum.\n",
"Hot metal gas forming (HMGF) is a method of die forming in which a metal tube is heated to a pliable state, near to but below its melting point, then pressurized internally by a gas in order to form the tube outward into the shape defined by an enclosing die cavity. The high temperatures allow the metal to elongate, or stretch, to much greater degrees without rupture than are possible in previously utilized cold and warm forming methods. In addition, the metal can be formed into finer details and requires less overall forming force than traditional methods.\n",
"An inert gas, such as Argon, is often used to quickly cool the treated metals back to non-metallurgical levels (below ) after the desired process in the furnace. This inert gas can be pressurized to two times atmosphere or more, then circulated through the hot zone area to pick up heat before passing through a heat exchanger to remove heat. This process continues until the desired temperature is reached.\n",
"The metal is either sodium or a sodium - potassium alloy (NaK). The molten metal is mixed with silica gel under constant agitation at room temperature. This phase 0 material must be handled in an inert atmosphere. Heating phase 0 at takes it to phase I. When this material is exposed to dry oxygen the reducing power is not affected. At further heating to phase II can be handled safely in an ambient environment. \n",
"where \"m\" is the electron rest mass. This Fermi energy corresponds to a Fermi temperature of the order of 10 kelvins, much higher than the temperature of the sun surface. Any metal will boil before reaching this temperature under atmospheric pressure. Thus for any practical purpose, a metal can be considered as a Fermi gas at zero temperature as a first approximation (normal temperatures are small compared to \"T\").\n",
"When heated to a temperature that is high enough for tetraethyl dithiopyrophosphate to decompose, it gives off fumes of phosphorus and sulfur oxides, which are highly toxic. It can explode if containers of it are heated, and it can burn, although it does not do so easily. The chemical can also polymerize explosively. The chemical also reacts to form toxic and flammable gases in the presence of hydrides and other reducing agents. It is able to corrode iron. When it does this, it can release hydrogen gas. The chemical has a specific gravity of 1.196 at and its vapor density is 13.17 grams per liter at . Its melting point is and its boiling point is between and at 2mm Hg. The chemical's sorption coefficient is 2.87 Log L/kg. Its Henry's Law constant is 0.000174594 at . Its octanol-water partition coefficient is 3.9804 Log L/kg. Tetraethyl dithiopyrophosphate's diffusion coefficient in air is 0.015 cm per second and its diffusion coefficient in water is 0.0000055 cm.\n"
] |
does anything significant happen to our bodies when we are shocked with low-level electricity? | We get shocked. We are mostly composed of water, which conducts electricity, and being exposed to electricity will jolt your whole body. That's why we react so quickly if we've ever been shocked.
It'll probably depend on voltage but it can be anything from muscle pain(including abnormal heart rhythm) all the way to burns. They did use electro shock therapy, maybe that's what ur referring to as low-level? | [
"Electricity is hazardous: an electric shock from a current as low as 35 milliamps is sufficient to cause fibrillation of the heart in vulnerable individuals. Even a healthy individual is at risk of falling from a high structure due to loss of muscle control. Higher currents can cause respiratory failure and result in extensive and life-threatening burns. The first recorded human fatality occurred in 1879 when a stage carpenter in Lyon, France touched a 250 volt wire. The lack of any visible sign that a conductor is energised, even at high voltages, makes electricity a particular hazard.\n",
"Electrical shocks on humans can lead to permanent disabilities or death. Size, frequency and duration of the electrical current affect the damage. The effects from electric shock can be: stopping the heart beating properly, preventing the person from breathing, causing muscle spasms. The skin features also affect the consequences of electric shock.\n",
"There are a variety of psychiatric effects that may occur due to electrical injuries. Recent research has found that functional differences in neural activation during spatial working memory and implicit learning oculomotor tasks have been identified in electrical shock victims. Frank behavioral changes can occur as well, even if the path of electrical current did not proceed through the head. Symptoms may include:\n",
"The health hazard of an electric current flowing through the body depends on the amount of current and the length of time for which it flows, not merely on the voltage. However, a high voltage is required to produce a high current through the body. This is due to the relatively high resistance of skin when dry, requiring a high voltage to pass through. The severity of a shock also depends on whether the path of the current includes a vital organ. \n",
"People who survive electrical trauma may suffer a host of injuries including loss of consciousness, seizures, aphasia, visual disturbances, headaches, tinnitus, paresis, and memory disturbances. Even without visible burns, electric shock survivors may be faced with long-term muscular pain and discomfort, fatigue, headache, problems with peripheral nerve conduction and sensation, inadequate balance and coordination, among other symptoms. Electrical injury can lead to problems with neurocognitive function, affecting speed of mental processing, attention, concentration, and memory. The high frequency of psychological problems is well established and may be multifactorial. As with any traumatic and life-threatening experience, electrical injury may result in post traumatic psychiatric disorders. There exist several non-profit research institutes that coordinate rehabilitation strategies for electrical injury survivors by connecting them with clinicians that specialize in diagnosis and treatment of various traumas that arise as a result of electrical injury.\n",
"The most serious electrolyte disturbances involve abnormalities in the levels of sodium, potassium or calcium. Other electrolyte imbalances are less common and often occur in conjunction with major electrolyte changes. Chronic laxative abuse or severe diarrhea or vomiting (gastroenteritis) can lead to electrolyte disturbances along with dehydration. People suffering from bulimia or anorexia nervosa are at especially high risk for an electrolyte imbalance.\n",
"Electrical current can cause interference with nervous control, especially over the heart and lungs. Repeated or severe electric shock which does not lead to death has been shown to cause neuropathy at the site where the current entered the body. The neurologic symptoms of electrical injury may occur immediately, which traditionally have a higher likelihood for healing, though they may also be delayed by days to years. The delayed neurologic consequences of electrical injury have a worse prognosis.\n"
] |
Am I causing myself any harm by heating my food in a plastic container? | Heat will thermally degrade some polymers into their constituent monomers and many of them are *potential* carcinogens. You are more likely to melt the polymer than break it down to monomers at microwave heat, however, so it isn't likely there is substantial contamination. Some contain plasticizers like BPA which may affect hormone signaling. If you want to know more about your specific polymer [this long PDF](_URL_0_) will educate you. | [
"Consumer groups recommend that people wishing to lower their exposure to bisphenol A avoid canned food and polycarbonate plastic containers (which shares resin identification code 7 with many other plastics) unless the packaging indicates the plastic is bisphenol A-free. The National Toxicology Panel recommends avoiding microwaving food in plastic containers, putting plastics in the dishwasher, or using harsh detergents on plastics, to avoid leaching.\n",
"Inappropriate storage containers and repair attempts: Cabinets made of inferior materials can give off harmful gases, while other reactive materials such as acidic paper sleeves, rubber bands, paper clips, pressure sensitive tape, and glues and adhesives commonly used for storage and repairs in the past can also cause chemical deterioration. Storing items too loosely, too tightly, or in enclosures that do not provide adequate physical protection can all cause physical damage such as curling and breakage.\n",
"There is ongoing concern as to the use of plastics in consumer food packaging solutions, environmental impact of the disposal of these products, as well as concerns regarding consumer safety. Karin Michaels, Associate Professor at Harvard Medical School, suggests that toxins leaching from plastics might be related to disorders such as infertility and cancer in humans.\n",
"Any container of food which has been heat-treated and then assumed to be airtight which shows signs of not being so, e.g., metal cans with pinprick holes from rust or mechanical damage, should be discarded. Contamination of a canned food solely with \"C. botulinum\" may not cause any visual defects to the container, such as bulging, or the food. Only assurance of sufficient thermal processing during production, and absence of a route for subsequent contamination, should be used as indicators of food safety.\n",
"“It is true that substances used to make plastics can leach into food,” says Edward Machuga, Ph.D., a consumer safety officer in the FDA’s Center for Food Safety and Applied Nutrition. “But as part of the approval process, the FDA considers the amount of a substance expected to migrate into food and the toxicological concerns about the particular chemical.” A couple of cases have caught media attention in recent years. One case is in regard to diethylhexyl adipate (DEHA). DEHA is a plasticizer, a substance added to some plastics in order to make them flexible. The public concerns about DEHA exposure while consuming food with plastic wraps. There are potentials of exposure to DEHA; however, the levels of the exposure are much lower than the no toxic effect levels in animal studies. Another case is in regard to the dioxins, labeled as “likely human carcinogen” by the Environmental Protection Agency. The public has been misled by the claims that plastics contain dioxins, while Machuga stated that no evidence that shows plastic containers or films contain dioxins was seen by the FDA. Overall the use of plastic wrap in the food industry does not pose danger to human health.\n",
"Health risks of materials and chemicals used in food packaging need to be carefully controlled. Carcinogens, toxic chemicals, mutagens etc. need to be eliminated from food contact and potential migration into foods.\n",
"Lightweight plastic bags are also blown into trees and other plants and can be mistaken for food. Plastic bags break down by polymer degradation but not by biodegradation. As a result, any toxic additives they contain—including flame retardants, antimicrobials, and plasticizers—will be released into the environment. Many of those toxins directly affect the endocrine systems of organisms, which control almost every cell in the body.\n"
] |
Historically, what has been the most successful form of government for an empire? | This is hard to answer because most empires changed government over time. The Roman Republic lasted centuries, and the Empire lasted over a millennia if you count Byzantium. The Holy Roman Empire did too, but how it was run changed over time. It's impossible to find an unchanged system for any length of time, even if the State or government continues. | [
"Politically, it was typical for either a monarchy or an oligarchy, rooted in the original core territory of the empire, to continue to dominate. If governmental authority was maintained by controlling water supplies, vital to colonial subjects, such régimes were called hydraulic empires.\n",
"Since antiquity, monarchy has contrasted with forms of democracy, where executive power is wielded by assemblies of free citizens. In antiquity, some monarchies were abolished in favour of such assemblies in Rome (Roman Republic, 509 BC), and Athens (Athenian democracy, 500 BC).\n",
"Many empires were the result of military conquest, incorporating the vanquished states into a political union, but imperial hegemony can be established in other ways. The Athenian Empire, the Roman Empire, and the British Empire developed at least in part under elective auspices. The Empire of Brazil declared itself an empire after separating from the Portuguese Empire in 1822. France has twice transitioned from being called the French Republic to being called the French Empire while it retained an overseas empire.\n",
"The idea and aspiration of world government has been known since the dawn of history. Bronze Age Egyptian Kings aimed to rule \"All That the Sun Encircles\", Mesopotamian Kings \"All from the Sunrise to the Sunset\", and ancient Chinese and Japanese Emperors \"All under Heaven\". These four civilizations developed impressive cultures of Great Unity, or Da Yitong as the Chinese put it. In 113 BC, the Han dynasty in China erected an Altar of the Great Unity.\n",
"History records transitions from monarchy to other forms of government from very early times, either through revolutions, coups d'état, wars, or legislative reforms (sometimes involving abdications). Athens had abandoned the principle of hereditary rule by 753 BCE. The founding of the Roman Republic in the 6th century BCE provides a well-known example and anti-monarchism became part of Rome's traditions, being cited as justification for the assassination of Julius Caesar in 44 BCE. Monarchical Carthage became an aristocratic republic in 308 BCE.\n",
"Since the beginning of antiquity, monarchy confronted several republican forms of government, wherein executive power was in the hands of a number of people that elected leaders in a certain way instead of appointing them by hereditary succession. During the archaic period (c. 750–500 BCE), kingship disappeared in almost all Greek poleis, and also in Rome (then still a barely significant town). After the demise of kingship, the Greek city-states were initially most often led by nobility (aristocracy), after which their economic and military power base crumbled. Next, in almost all poleis tyrants usurped power for two generations (tyranny, 7th and especially 6th century BCE), after which gradually forms of governments led by the wealthy (oligarchy) or assemblies of free male citizens (democracy) emerged in Classical Greece (mainly after 500 BCE). Athenian democracy (6th century–322 BCE) is the best-known example of the latter form; classical Sparta (c. 550–371 BCE) was a militaristic polis with a remarkable mix between monarchy (dual kingship), aristocracy (Gerousia) and democracy (Apella); the Roman Republic (c. 509–27 BCE) had a mixed constitution of oligarchy, democracy and especially aristocracy.\n",
"After the end of the Gupta Empire and the collapse of the Harsha Empire, power became decentralised in India. Several larger kingdoms emerged, with \"countless vasal states\". The kingdoms were ruled via a feudal system. Smaller kingdoms were dependent on the protection of the larger kingdoms. \"The great king was remote, was exalted and deified\", as reflected in the Tantric Mandala, which could also depict the king as the centre of the mandala.\n"
] |
During the American Civil War, was Washington D.C. actually the "most fortified city on earth"? | Follow up question, what would these fortifications look like? How large was DC's Garrison? | [
"During the American Civil War (1861–65), Washington County contained a partial circle of defensive fortifications that made Washington one of the most heavily fortified cities in the world at that time. The forts surrounding Union-held territory in Virginia completed the defense circle. The Battle of Fort Stevens, July 11–12, 1864, took place in Washington County.\n",
"In the opening days of the American Civil War, the defenses of Washington D.C. were primarily concerned with an overland attack on the capital city of the United States. In 1861, the Arlington Line was constructed to help defend the city from attack via the direct, Virginia approach. Additional forts were constructed on the city's northern approaches to defend against any attacks from Maryland. At sea, however, only Fort Washington, a fort originally built to defend the city in the War of 1812 blocked the approach along the Potomac River.\n",
"Washington, D.C., during the American Civil War was the nerve-center of the Union war effort, which rapidly turned it from a small city into a major capital with full civic infrastructure and strong defenses.\n",
"The Civil War Defenses of Washington were a group of Union Army fortifications that protected the federal capital city, Washington, D.C., from invasion by the Confederate States Army during the American Civil War (see Washington, D.C., in the American Civil War). The sites of some of these fortifications are within a collection of National Park Service (NPS) properties that the National Register of Historic Places identifies as the Fort Circle. The sites of other such fortifications in the area have become parts of state, county or city parks or are located on privately owned properties.\n",
"Fort Lincoln was one of seven temporary earthwork forts part of the Civil War Defenses of Washington, DC during the Civil War built in the Northeast quadrant of the city at the beginning of the Civil War by the Union Army to protect the city from the Confederate Army. From west to east, the forts were as follow: Fort Slocum, Fort Totten, Fort Slemmer, Fort Bunker Hill, Fort Saratoga, Fort Thayer and Fort Lincoln.\n",
"The fort was one of the ring of Union Army fortifications that the Union Army constructed as part of the Civil War defenses of Washington (see Washington, D.C., in the American Civil War). It was one of 33 forts on the Virginia side of the Potomac River that made up a defense line (the Arlington Line) for the national capital city.\n",
"The Washington area had 68 major enclosed forts, as well as 93 prepared (but unarmed) batteries for field guns, and seven blockhouses surrounding it during the American Civil War. There were also twenty miles of rifle pits and thirty miles of connecting military roads. These were Union forts, and the Confederacy never captured one. Indeed, most never came under enemy fire. These were used to house soldiers and store artillery and other supplies.\n"
] |
Does climate change effect the occurrence of different cloud types? | The effect that global warming has on clouds is actually a very difficult scientific question! To answer your questions directly though; 1) it would be difficult for a person to notice changes in cloud cover or cloud types without some systematic study - mostly because any significant changes will happen over 10, 20, 30 years and it's just very difficult for humans to notice changes on those timescales (this is also kind of a fundamental reason why we're so bad at dealing with global warming). 2) I can't think of any cloud types that will go "extinct" on a global scale. Most predicted changes involve increases or decreases of either high or low cloud in different regions of the world, so I guess it's possible that certain clouds types could become less common in specific regions. However, a prediction this specific is beyond our current abilities. I'll explain why.
Clouds exist on a huge range of spatial and temporal scales; from tiny water droplets to country-sized banks of clouds. They also depend on the global and local winds, temperatures, water availability, geography (i.e. mountain ranges), etc. Basically they're really complicated! One way we can make predictions about global warming is with computer models, where we divide up the global atmosphere into boxes, and for each box we have a set of equations to predict what will happen within it. The size of the boxes is the resolution (think of it like pixels on a screen). The difficult thing with clouds is they can be smaller than the box, which means you can't explicitly model every cloud. Instead you use equations that tell you the average effect of clouds within each box. On a global scale this is quite good at telling us how "average" clouds will change, and what that effect on the climate might be, but it's very difficult to say exactly what will happen on smaller scales, and clouds remain a major uncertainty in future climate change predictions, e.g. [ipcc](_URL_0_).
Hope that answers your question, happy to clarify anything. | [
"The number and type of CCNs can affect the precipitation amount, lifetimes and radiative properties of clouds as well as the amount and hence have an influence on climate change; details are not well understood but are the subject of research. There is also speculation that solar variation may affect cloud properties via CCNs, and hence affect climate.\n",
"Cloud effects are a significant area of uncertainty in climate models. Clouds have competing effects on climate. They cool the surface by reflecting sunlight into space; they warm it by increasing the amount of infrared radiation transmitted from the atmosphere to the surface. In the 2001 IPCC report possible changes in cloud cover were highlighted as a major uncertainty in predicting climate.\n",
"Clouds continue to be the dominant source of uncertainty in 3-D global climate models, and a consensus has yet to be reached on exactly how changes in cloud spatial patterns and cloud type may have affected Earth's climate during this time.\n",
"Changes in cloud cover are closely coupled with other feedback, including the water vapor feedback and ice-albedo feedback. Changing climate is expected to alter the relationship between cloud ice and supercooled cloud water, which in turn would influence the microphysics of the cloud which would result in changes in the radiative properties of the cloud. Climate models suggest that a warming will increase fractional cloudiness. The albedo of increased cloudiness cools the climate, resulting in a negative feedback; while the reflection of infrared radiation by clouds warms the climate, resulting in a positive feedback. Increasing temperatures in the polar regions is expected in increase the amount of low-level clouds, whose stratification prevents the convection of moisture to upper levels. This feedback would partially cancel the increased surface warming due to the cloudiness. This negative feedback has less effect than the positive feedback. The upper atmosphere more than cancels negative feedback that causes cooling, and therefore the increase of CO is actually exacerbating the positive feedback as more CO enters the system.\n",
"As difficult as it is to evaluate the influences of current clouds on current climate, it is even more problematic to predict changes in cloud patterns and properties in a future, warmer climate, and the resultant cloud influences on future climate. In a warmer climate more water would enter the atmosphere by evaporation at the surface; as clouds are formed from water vapor, cloudiness would be expected to increase. But in a warmer climate, higher temperatures would tend to evaporate clouds. Both of these statements are considered accurate, and both phenomena, known as cloud feedbacks, are found in climate model calculations. Broadly speaking, if clouds, especially low clouds, increase in a warmer climate, the resultant cooling effect leads to a negative feedback in climate response to increased greenhouse gases. But if low clouds decrease, or if high clouds increase, the feedback is positive. Differing amounts of these feedbacks are the principal reason for differences in climate sensitivities of current global climate models. As a consequence, much research has focused on the response of low and vertical clouds to a changing climate. Leading global models produce quite different results, however, with some showing increasing low clouds and others showing decreases. For these reasons the role of tropospheric clouds in regulating weather and climate remains a leading source of uncertainty in global warming projections.\n",
"Addition of cloud nuclei by pollution can lead to an increase in solar radiation reflected by clouds. Increasing aerosol concentration and aerosol density increases cloud droplet concentration, decreases cloud droplet size, and increases cloud albedo. In macrophysically identical clouds, a cloud with few larger drops will have a lower albedo than a cloud with more smaller drops.\n",
"In addition to how clouds themselves will respond to increased temperatures, other feedbacks affect clouds properties and formation. The amount and vertical distribution of water vapor is closely linked to the formation of clouds. Ice crystals have been shown to largely influence the amount of water vapor. Water vapor in the subtropical upper troposphere has been linked to the convection of water vapor and ice. Changes in subtropical humidity could provide a negative feedback that decreases the amount of water vapor which in turn would act to mediate global climate transitions.\n"
] |
portuguese drug laws | Well, I'm portuguese. My only experience is with marijuana so I will only talk about it. Marijuana isn't legal, but it isn't really criminalized, I mean, you can have with you up to 5g, if you have more, you'll be charged with Possession of drugs, but less than that it's generally fine.
About smoking, some places are cool with it, others may ask you to stop it, others may call the cops. Really depends on the person itself.
Sometimes cops that catch you smoking will take it from you and walk away, other times they'll just ask you to do it somewhere more privately. | [
"The drug policy of Portugal was put in place in 2001, and was legally effective from July 2001. The new law maintained the status of illegality for using or possessing any drug for personal use without authorization. However, the offense was changed from a criminal one, with prison a possible punishment, to an administrative one if the amount possessed was no more than a ten-day supply of that substance.\n",
"While drug use is illegal in Portugal, the law's introduction notes of occasional drug users: \"it is necessary above all to avoid them being labelled, marginalised, pushed into an impasse or towards avenues whose only way out is drugs.\" However, the Portuguese government condemned the Dutch pragmatic policy, well known for its absence of user punishment.\n",
"Portugal has arguably the most liberal laws concerning possession of illicit drugs in the Western world. In 2001 Portugal decriminalized possession of effectively all drugs that are still illegal in other developed nations including, but not limited to, marijuana, cocaine, heroin, and LSD. While possession is not a crime, trafficking and possession of more than \"10 days worth of personal use\" are still punishable by jail time and fines.\n",
"In Portugal, recreational use of cannabis is forbidden by law; also the medicinal use is not yet officially recognized (there is debate and legislators have proposed bills in the Portuguese Parliament). Portugal signed all the UN conventions on narcotics and psychotropic to date. With the 2001 decriminalization bill, the consumer is now regarded as a patient and not as a criminal (having the amount usually used for ten days of personal use is not a punishable crime) but repression persists. One can be sent to a dissuasion committee and have a talk or must pay a fee. According to the libertarian think tank Cato Institute, illegal drug use among Portuguese teenagers declined after 2001, and 45 percent of the country's heroin addicts sought medical treatment. But critics of the policy, such as the Association for a Drug-Free Portugal, say overall consumption of drugs in the country has actually risen by 4.2 percent since 2001 and claim the benefits of decriminalization are being \"over-egged.\"\n",
"Portugal is also known for having decriminalized the usage of all common drugs in 2001, the first country in the world to do so. Portugal decriminalized possession of effectively all drugs that are still illegal in other developed nations including cannabis, cocaine, heroin, and LSD. While possession is legal, trafficking and possession of more than \"10 days worth of personal use\" are still punishable by jail time and fines. People caught with small amounts of any drug are given the choice to go to a rehab facility, and may refuse treatment without consequences. Despite criticism from other European nations, who stated Portugal's drug consumption would tremendously increase, overall drug use has declined along with the number of HIV infection cases, which had dropped 50 percent by 2009. Drug use among 16- to 18-year-olds also declined, however the use of marijuana rose only slightly among that age group.\n",
"In 2001 Portugal began treating use and possession of small quantities of drugs as a public health issue. This means rather than incarcerating those in possession they are referred to a treatment program. The drugs are still illegal, the police just handles the situation differently. This also decreases the amount of money the government spends fighting a war on drugs and money spent keeping drug users incarcerated.\n",
"In July 2001, a law maintained the status of illegality for using or possessing any drug for personal use without authorization. The offense was however changed from a criminal one, with prison a possible punishment, to an administrative one if the possessing was no more than up to ten days' supply of that substance. This was in line with the de facto Portuguese drug policy before the reform. Drug addicts were then aggressively targeted with therapy or community service rather than fines or waivers. Even if there are no criminal penalties, these changes did not legalize drug use in Portugal. Possession has remained prohibited by Portuguese law, and criminal penalties are still applied to drug growers, dealers and traffickers.\n"
] |
what is the science behind being a good socialiser? what makes a 'good conversation'? | The gift of bullshit is an important one. That's number one. Second, it does help to be educated across the board, but if this fails, fall back on number one. Don't talk about yourself either. Not everything has to relate back to you. Those people are the worst. | [
"BULLET::::4. Be a good listener. Encourage others to talk about themselves. The easiest way to become a good conversationalist is to become a good listener. To be a good listener, we must actually care about what people have to say. Many times people don't want an entertaining conversation partner; they just want someone who will listen to them.\n",
"Participation of people in online communities, in general, differ from their participatory behavior in real-world collective contexts. Humans in daily life are used to making use of \"social cues\" for guiding their decisions and actions e.g. if a group of people is looking for a good restaurant to have lunch, it is very likely that they will choose to enter to a local that have some customers inside instead of one that it is empty (the more crowded restaurant could reflect its popularity and in consequence, its quality of service). However, in online social environments, it is not straightforward how to access to these sources of information which are normally being logged in the systems, but this is not disclosed to the users.\n",
"Participation of people in online communities, in general, differ from their participatory behavior in real-world collective contexts. Humans in daily life are used to making use of \"social cues\" for guiding their decisions and actions e.g. if a group of people is looking for a good restaurant to have lunch, it is very likely that they will choose to enter to a local that have some customers inside instead of one that it is empty (the more crowded restaurant could reflect its popularity and in consequence, its quality of service). However, in online social environments, it is not straightforward how to access to these sources of information which are normally being logged in the systems, but this is not disclosed to the users.\n",
"CHAT is a national youth mental health programme that aims to make it easy and unthreatening for youths to seek advice and help for their emotional and mental health issues. The CHAT team does this by raising awareness of youth mental health, and providing a free, confidential assessment service and mental health information. CHAT also partners polytechnics and post-secondary institutions to reach out to and support their students.\n",
"It enabled people to keep up with what was going on in their social network. It also creates a bond between the teller and the hearer, as they share information of mutual interest and spend time together. It also helps the hearer learn about another individual’s behavior and helps them have a more effective approach to their relationship. Dunbar (2004) found that 65% of conversations consist of social topics.\n",
"\"Naturally, this is not always successful. Conversation is diffuse, disjointed, full of popular sayings and banalities local in time and place which do not express character at all, or very little. My purpose, in making characters somewhat eloquent, is the expression of two psychological truths; first, that everyone has a wit superior to his everyday wit, when discussing his personal problems, and the most depressed housewife, for example, can talk like Medea about her troubles; second, that everyone, to a greater or lesser extent, is a fountain of passion, which is turned by circumstances of birth or upbringing into conventional channels – as, ambition, love, money-grubbing, politics, but which could be as well applied to other objects and with less waste of energy.\"\n",
"Almost any time there is a social gathering of some sort, the conversation will include gossip and argumentation which entails moral judgments and evaluations about the rightness or wrongness of the actions of others. Even people who normally do not enjoy intricate arguments tend to reason acutely and with great attention to detail when they are caught about in the justification or condemnation of their next-door neighbors' behavior.\n"
] |
in print, especially transcribed interviews, what is the reason for the brackets? "jane said [tom] never had a bad thing to say about anyone." | The brackets are usually replacing a pronoun, a nick-name or first or last name only when context isn't present to make it clear who they're referring to.
It would say something like "Jane said he never had a bad thing to say about anyone", which is confusing if they haven't specified that it's Tom they're talking about (or she referred to him by, say, "T-Dawg" or some shit like that). It's always just to clarify and the brackets mean that those words were substituted for other words for the sake of understanding. | [
"That and almost everything else could be forgotten amidst Jane Ace's linguistic mayhem, much of it provided by her wry husband's scripts and enough improvised by her. (Mary Hunter's real laughter, at Jane's malaprops or Ace's arch barbs, was practically the show's laugh track, years before anyone ever thought of using canned laughter.) Known as often as not as \"Jane-isms,\" the better remembered of her twisted turns of phrase were more than a match for Gracie Allen's equally celebrated illogical logic, anticipating such later word and context manglers as Jimmy Durante, Lou Costello, Phil Harris, and, especially, \"All in the Family\"'s Archie Bunker. The famed Jane-isms included:\n",
"McCarthy told Oprah Winfrey in an interview that he prefers \"simple declarative sentences\" and that he uses capital letters, periods, an occasional comma, a colon for setting off a list, but never semicolons. He does not use quotation marks for dialogue and believes there is no reason to \"blot the page up with weird little marks\". Describing events of extreme violence, McCarthy's prose is sparse, yet expansive, with an often biblical quality and frequent religious references. McCarthy's writing style involves many unusual or archaic words, no quotation marks for dialogue, and no apostrophes to signal most contractions.\n",
"According to Arthur Marshall, she was famous for her indecent, though entirely innocent, remarks. \"The physical side of life had passed her by, together with the words, slang and otherwise, that accompany it. Time and again she settled for an unfortunate word or phrase. Inviting Noël Coward to lunch during the war, when food was difficult, she boomed encouragement down the telephone; 'Do come! I've got such a lovely cock.' ('I do wish you'd call it a hen', Noel answered). To use correctly, in a literary sense, the words 'erection', 'tool' and 'spunk' was second nature to her. When wishing to describe herself as being full of life and creative energy, she chose, not really very wisely, the word 'randy'.\"\n",
"McCarthy makes sparse use of punctuation, even replacing most commas with \"and\" (a polysyndeton). He told Oprah Winfrey in an interview that he prefers \"simple declarative sentences\" and that he uses capital letters, periods, an occasional comma, a colon for setting off a list, but never semicolons. He does not use quotation marks for dialogue and believes there is no reason to \"blot the page up with weird little marks\". Erik Hage notes that McCarthy's dialogue also often lacks attribution, but that \"[s]omehow...the reader remains oriented as to who is speaking\". His attitude to punctuation dates to some editing work he did for a professor of English while he was enrolled at the University of Tennessee, when he stripped out much of the punctuation in the book being edited, which pleased the professor. McCarthy also edited fellow Santa Fe Institute Fellow W. Brian Arthur's influential article \"Increasing Returns and the New World of Business\", published in the \"Harvard Business Review\" in 1996, removing commas from the text. He has also done copy-editing work for physicists Lawrence M. Krauss and Lisa Randall.\n",
"David Frum, former special assistant to President George W. Bush (emphasis in the original): \"Limbaugh's verbal abuse of Sandra Fluke set a new kind of low. I can't recall \"anything\" as brutal, ugly and deliberate ever being said by such a prominent person and so emphatically repeated. This was not a case of a bad 'word choice'. It was a brutally sexualized accusation, against a specific person, prolonged over three days.\"\n",
"Politician and activist Zoe O'Connell described some of the wording in the narration as \"cringeworthy\", but felt that \"it’s more than just a step in the right direction, it’s a programme that pretty accurately reflected how many trans people carry on with each other in private.\"\n",
"A typical conversation for the Count will involve his confusing both himself and others, while becoming drastically sidetracked from the matter in hand. He is usually oblivious to the chaos he causes, often blaming his interlocutors for any confusion. On the rare occasions he realises he is at fault, he often attempts to divert the blame by lying. Inevitably becoming confused by his own lies, his last resort is usually to claim he was recording a stunt for a hidden camera show.\n"
] |
Why does 2-stroke engine exhaust smell different from 4-stroke? | Primarily because in a 2-stroke engine there's no dedicated lubrication system, so you have to mix oil directly into the gas. The combustion of that oil means you end up creating a lot of smoke compared to pure gas, which burns cleaner.
Additionally a car is going to have a lot more bells-and-whistles related to clean combustion, like a catalytic converter that cleans up exhaust. | [
"The engine is also 4-stroke — unusual when almost all pedal-equipped mopeds used simpler 2-strokes. Soichiro Honda disliked the sharp noise of 2-strokes, and the 4-stroke does not require oil to be mixed with the gasoline at every fill-up.\n",
"Unlike a four-stroke engine, whose crankcase is closed except for its ventilation system, a two-stroke engine uses the crankcase as part of the induction tract, and therefore, oil must be mixed with gasoline to be distributed throughout the engine for lubrication. The resultant mix is referred to as premix or petroil. This oil is ultimately burned along with the fuel as a total-loss oiling system. This results in increased exhaust emissions, sometimes with excess smoke and/or a distinctive odor.\n",
"As is typical of two-stroke designs, the Jumos used fixed intake and exhaust ports instead of valves, which were uncovered when the pistons reached a certain point in their stroke. Normally such designs have poor volumetric efficiency because both ports open and close at the same time and are generally located across from each other in the cylinder. This leads to poor scavenging of the burnt charge, which is why valve-less two-strokes generally run smoky and are inefficient.\n",
"A fundamental difference from typical four-stroke engines is that the two-stroke's crankcase is sealed and forms part of the induction process in gasoline and hot bulb engines. Diesel two-strokes often add a Roots blower or piston pump for scavenging.\n",
"Apart from large diesels with separate superchargers, two-stroke engines are generally piston-ported and use their crankcase beneath the piston for compression. The cylinder has a transfer port (inlet from crankcase to cylinder) and an exhaust port cut into it. These are opened, as the piston moves downwards past them; with the higher exhaust port opening earlier as the piston descends; and closing later as the piston rises.\n",
"Two-stroke diesel engines use only two strokes instead of four strokes for a complete engine cycle. Filling the cylinder with air and compressing it takes place in one stroke, and the power and exhaust strokes are combined. The compression in a two-stroke diesel engine is similar to the compression that takes place in a four-stroke diesel engine: As the piston passes through bottom centre and starts upward, compression commences, culminating in fuel injection and ignition. Instead of a full set of valves, two-stroke diesel engines have simple intake ports, and exhaust ports (or exhaust valves). When the piston approaches bottom dead centre, both the intake and the exhaust ports are \"open\", which means that there is atmospheric pressure inside the cylinder. Therefore, some sort of pump is required to blow the air into the cylinder and the combustion gasses into the exhaust. This process is called \"scavenging\". The pressure required is approximately 10...30 kPa.\n",
"Gas flow within the two-stroke engine is even more critical than for a four-stroke engine, as the two flows are both entering and leaving the combustion chamber simultaneously. A well-defined flow pattern is required, avoiding any turbulent mixing. The efficiency of the two-stroke engine depends on effective scavenging, the more complete replacement of the old spent charge with a fresh charge.\n"
] |
how a sql index works? | Imagine I've got a pile of Lego, and I'm looking for a piece. Without an index is like looking at every piece individually until I find the one I'm looking for.
If I made a note of every piece of Lego was when I took it out of the box, when I wanted to find a piece, I could look up this list of Lego pieces and it would tell me where to find the one I wanted. | [
"A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes and storage space to maintain the index data structure. Indexes are used to quickly locate data without having to search every row in a database table every time a database table is accessed. Indexes can be created using one or more columns of a database table, providing the basis for both rapid random lookups and efficient access of ordered records.\n",
"SQL includes operators and functions for calculating values on stored values. SQL allows the use of expressions in the \"select list\" to project data, as in the following example, which returns a list of books that cost more than 100.00 with an additional \"sales_tax\" column containing a sales tax figure calculated at 6% of the \"price\".\n",
"An index is one way of providing quicker access to data. Indexes can be created on any combination of attributes on a relation. Queries that filter using those attributes can find matching tuples randomly using the index, without having to check each tuple in turn. This is analogous to using the index of a book to go directly to the page on which the information you are looking for is found, so that you do not have to read the entire book to find what you are looking for. Relational databases typically supply multiple indexing techniques, each of which is optimal for some combination of data distribution, relation size, and typical access pattern. Indices are usually implemented via B+ trees, R-trees, and bitmaps.\n",
"An index is a copy of selected columns of data from a table that can be searched very efficiently that also includes a low-level disk block address or direct link to the complete row of data it was copied from. Some databases extend the power of indexing by letting developers create indexes on functions or expressions. For example, an index could be created on upper(last_name), which would only store the upper-case versions of the codice_1 field in the index. Another option sometimes supported is the use of partial indices, where index entries are created only for those records that satisfy some conditional expression. A further aspect of flexibility is to permit indexing on user-defined functions, as well as expressions formed from an assortment of built-in functions.\n",
"In databases an \"index\" is a data structure, part of the database, used by a database system to efficiently navigate access to \"user data\". Index data are system data distinct from user data, and consist primarily of pointers. Changes in a database (by insert, delete, or modify operations), may require indexes to be updated to maintain accurate user data accesses. Index locking is a technique used to maintain index integrity. A portion of an index is locked during a database transaction when this portion is being accessed by the transaction as a result of attempt to access related user data. Additionally, special database system transactions (not user-invoked transactions) may be invoked to maintain and modify an index, as part of a system's self-maintenance activities. When a portion of an index is locked by a transaction, other transactions may be blocked from accessing this index portion (blocked from modifying, and even from reading it, depending on lock type and needed operation). Index Locking Protocol guarantees that Phantom Phenomenon won't occur. \n",
"Indexing is a technique some storage engines use for improving database performance. The many types of indexes share the common property that they reduce the need to examine every entry when running a query. In large databases, this can reduce query time/cost by orders of magnitude. The simplest form of index is a sorted list of values that can be searched using a binary search with an adjacent reference to the location of the entry, analogous to the index in the back of a book. The same data can have multiple indexes (an employee database could be indexed by last name and hire date).\n",
"An expression index, also known as a function based index, is a database index that is built on a generic expression, rather than one or more columns. This allows indexes to be defined for common query conditions that depend on data in a table, but are not actually stored in that table.\n"
] |
why are islamic extremist groups predominantly sunni muslims rather than shia? | Sunni Muslims make up about 85-90% of all muslim groups, however there are a pretty large percentage of Shia Muslim extremists, because of the Shiite population in Iran, Iraq and other areas in politically unstable regions (Sunni's are also in this area, but are more concentrated to Eastern Asian areas and Northern Africa. | [
"Within Islam, there has been conflict at various periods between Sunnis and Shias; Shi'ites consider Sunnis to be damned, due to their refusal to accept the first Caliph as Ali and accept all following descendants of him as infallible and divinely guided. Many Sunni religious leaders, including those inspired by Wahhabism and other ideologies have declared Shias to be heretics or apostates.\n",
"Sunnis are a majority in most Muslim communities in China and Central Asia, South Asia, Southeast Asia, Africa, most of the Arab World, Turkey and among Muslims in the United States (of which 85–90% are Sunnis). This can also be confusing because the majority of Arab Muslims in the United States are Shia, while the majority of Arab Americans are Christians, the conflation of Arab and Muslim being quite common.\n",
"Sunni and Shia are different sects of Islam and the difference of opinions have resulted in many Fatwas, non-binding but authoritative legal opinion or learned interpretation issues pertaining to the Islamic law. Fatwas are based on the question and answer process found in the Quran, which seeks to enlighten on theological and philosophical issues, hadith, legal theory, duties, and the Sharia law. Sunni fatwas have been used to justify the persecution of Shia throughout their history.\n",
"The majority of Sunni Muslims were Arab nationalists, but not Ba'athist, making them feel alienated. The party was chiefly dominated by minority groups such as Alawites, Druzes, and Isma'ilis, and people from the countryside in general; this created an urban–rural conflict based predominantly on ethnic differences. With its coming to power, the Ba'ath Party was threatened by the predominantly anti-Ba'athist sentiment in urban politics—probably the only reason why the Ba'athists managed to stay in power was the rather weakly organised and fragmented opposition it faced.\n",
"In some cases Sunni and Shia have the same view, for example regarding Abū Lahab, Amr ibn Hishām and Umayyah ibn Khalaf. But controversies arise concerning the Sahabah since Sunnis believe in the uprightness of all Sahaba while Shia do not.\n",
"The persecution of Mahdavis by Sunni militants as of 2014 has been part of the larger backlash against religious minorities in Pakistani Balochistan, targeting Hindus, Hazaras, Shias, and Zikris, resulting in the migration of over 300,000 Shias, Zikris, and Hindus from Pakistani Balochistan.\n",
"According to scholar Vali Nasr, political tendencies of Sunni and Shia Islamic ideology differ, with Sunni Islamic revivalism \"in Pakistan and much of the Arab world\" being \"far from politically revolutionary\", while Shia political Islam is strongly influenced by Ruhollah Khomeini and his talk of the oppression of the poor and class war. Sunni revivalism \"is rooted in conservative religious impulses and the bazaars, mixing mercantile interests with religious values.\" ... Khomeini's version of Islamism engaged the poor and spoke of class war.\n"
] |
what does it mean when the potus says that china is illegally manipulating it's currency. | You trade 2 baseball cards for 2 candy pieces, or you can trade 2 cards for 2 sandwiches, or 2 cards for 2 books. But then a new kid shows up and starts giving you a trade at 2 cards for 4 candies. Pretty sweet deal, you start trading a lot with that new kid.
Baseball Cards = $US Dollar. Candy = Chinese Dollar (Yuan).
Here, someone is using $2 to buy 400 Yuan (2 cards for 4 candy). Normally if they do this a ton they you should charge $3 for the 400, then $4 for 400, and so on. So, normally the Chinese dollar should go up and the US vs Yuan would go down.
However, the kid giving you the sweet deal is getting really good experience running his business, and he wants to keep it going (he was really poor before), but knows people will stop when it's more expensive. So what the kid does is artificially buy more baseball cards, so that his candy value goes back up, even if he has no plans on really using them. This continues the cheap trades for longer and longer.
_____
This is what China is doing. They are keeping their dollar low so people can buy their goods cheap. Normally you'd need Chinese people buying US computers or US cars for the dollars to be more equal, but the Chinese government is just buying lots of US bonds/property/etc. on their behalf.
> How does doing so effect the global economy?
When I was last looking at global economics (2-ish years ago) most people considered the US/China relation to be a really unstable dance that was going faster and faster. Both sides were getting *really* rich off each other, China was growing super fast, American citizens were filling their house with more stuff from Walmart. People looking in were like "jeezu christ!, grow at 2% a year not 12%!".
> Why does the US get so mad about it?
If the US wants to compete at candy (manufacturing, cheap factory work) they're fighting stacked terms. They can't compete with the cheaper Chinese dollar, which is kept artificially low. Note the POTUS needs to walk a fine line of complaining about their low dollar, while their businesses buy billions of dollars of stuff from them the very next minute. | [
"Trump has vowed to label China as a currency manipulator on his first day in office. \"Washington Post\" fact-checker Glenn Kessler, citing experts such as C. Fred Bergsten, found that \"Trump's complaints about currency manipulation are woefully out of date,\" noting that \"China has not manipulated its currency for at least two years.\"\n",
"In a written statement, Geithner said that China is manipulating the Renminbi by purposefully keeping its value low in order to make its exported products seem cheaper on the world market. If confirmed, Geither said to the Senate Finance Committee that he would ask the Obama administration to pressure China diplomatically to change this practice, more strongly than the Bush administration did. The United States maintains that China's actions hurt American businesses and contributed to the financial crisis.\n",
"The view that China manipulates its currency for its own benefit in trade has been criticized by Cato Institute trade policy studies fellow Daniel Pearson, National Taxpayers Union Policy and Government Affairs Manager Clark Packard, entrepreneur and Forbes contributor Louis Woodhill, Henry Kaufman Professor of Financial Institutions at Columbia University Charles W. Calomiris, economist Ed Dolan, William L. Clayton Professor of International Economic Affairs at the Fletcher School, Tufts University Michael W. Klein, Harvard University Kennedy School of Government Professor Jeffrey Frankel, Bloomberg columnist William Pesek, Quartz reporter Gwynn Guilford, The Wall Street Journal Digital Network Editor-In-Chief Randall W. Forsyth, United Courier Services, and China Learning Curve.\n",
"In written comments to the Senate Finance Committee during his confirmation hearings, Geithner stated that the new administration believed China was \"manipulating\" its currency and that the Obama administration would act \"aggressively\" using \"all the diplomatic avenues\" to change China's currency practices. The Obama administration would pressure China diplomatically to change this practice more strongly than the George W. Bush Administration had done. The United States maintained that China's actions hurt American businesses and contributed to the financial crisis.\n",
"Paul Krugman argued in 2010, that China intentionally devalued its currency to boost its exports to the United States and as a result, widening its trade deficit with the US. Krugman suggested at that time, that the United States should impose tariffs on Chinese goods. Krugman stated:\n",
"Currency manipulation by governments and their central banks cause differences in labor cost. On May 1, 2002, Economist and former Ambassador Ernest H. Preeg testified before the Senate committee on Banking, Housing, and Urban Affairs that China, for instance, pegs its currency to the dollar at a sub-par value in violation of Article IV of the International Monetary Fund Articles of Agreement which state that no nation shall manipulate its currency to gain a market advantage.\n",
"Economist Paul Krugman also wrote similar comments during October 2009, further arguing that China's currency should have appreciated relative to the U.S. dollar beginning around 2001. Various U.S. officials have also indicated concerns with Chinese exchange rate policies, which have not allowed its currency to appreciate significantly relative to the dollar despite large trade surpluses. In January 2009, Timothy Geithner wrote: \"Obama -- backed by the conclusions of a broad range of economists -- believes that China is manipulating its currency...the question is how and when to broach the subject in order to do more good than harm.\"\n"
] |
Is there information on the distribution of stars by metallicity? | Overall disclaimer: The metallicity of any given star is a complex mess, especially when you start talking about stars cooler than our Sun (which represent the bulk of stars). It's really tough to measure the overall metallicity of a given star, even with high resolution spectroscopy, and it's doubly complicated when trying to talk about it using just [Fe/H]. Distances for most stars are difficult to pin down much past 500 parsecs (~1600 light years) until [ESA's GAIA mission](_URL_0_) launches, though it's possible to get rough approximations through other methods with significantly higher uncertianties.
You seem to be interested in what's usually called the metallicity distribution function, and in practice it's restricted to specific stellar populations to avoid contamination from other galactic components. Stars in the galactic halo, bulge, and disk represent different epochs of star formation, and, as such, will probably have different average metalicities. Low metallicity stars represent a much, much higher fraction for stars in the halo vs. those in the disk, for example, though the intense star formation in the galactic bulge during our galaxy's formation left a number of old, metal poor stars in the galactic bulge as well. The wiki page on [metallicity](_URL_1_) is...okay for an introduction to the stellar populations topic as a whole, though that figure is probably too simplistic.
All in all I don't want to throw off numbers off the top of my head since I'm not familiar with some of the newest work, but a galactic structure person might be able to chime in with more information. If you're up for a technical read, the [SEGUE project has a paper considering the MDF of G and K stars](_URL_2_). You can check out some of the figures attached at the end of the PDF, specifically Fig. 16, where they examine [Fe/H] trends for G and K stars as a function of height above the galactic plane, but again, this is a restricted population of stars. | [
"A star's metallicity measurement is one parameter that helps determine whether a star has planets and the type of planets, as there is a direct correlation between metallicity and the type of planets a star may have. Measurements have demonstrated the connection between a star's metallicity and gas giant planets, like Jupiter and Saturn. The more metals in a star and thus its planetary system and proplyd, the more likely the system may have gas giant planets and rocky planets. Current models show that the metallicity along with the correct planetary system temperature and distance from the star are key to planet and planetesimal formation. For two stars that have equal age and mass but different metallicity, the less metallic star is bluer. Among stars of the same color, less metallic stars emit more ultraviolet radiation. The Sun, with 8 planets and 5 known dwarf planets, is used as the reference, with a [Fe/H] of 0.00.\n",
"Astronomers define the metallicity of a star as the abundance of chemical elements that have a higher atomic number than helium. This is measured by a spectroscopic analysis of the atmosphere, followed by a comparison with the results expected from computed stellar models. In the case of IK Pegasus A, the estimated metal abundance is [M/H] = +0.07 ± 0.20. This notation gives the logarithm of the ratio of metal elements (M) to hydrogen (H), minus the logarithm of the Sun's metal ratio. (Thus if the star matches the metal abundance of the Sun, this value will be zero.) A logarithmic value of 0.07 is equivalent to an actual metallicity ratio of 1.17, so the star is about 17% richer in metallic elements than the Sun. However the margin of error for this result is relatively large.\n",
"The Metallicity distribution function is an important concept in stellar and galactic evolution. It is a curve of what proportion of stars have a particular metallicity ([Fe/H], the relative abundance of iron and hydrogen) of a population of stars such as in a cluster or galaxy.\n",
"The overall stellar metallicity is often defined using the total iron content of the star, as iron is among the easiest to measure with spectral observations in the visible spectrum (even though oxygen is the most abundant heavy element – see metallicities in HII regions below). The abundance ratio is defined as the logarithm of the ratio of a star's iron abundance compared to that of the Sun and is expressed thus:\n",
"BULLET::::- What is the origin of the stellar mass spectrum? That is, why do astronomers observe the same distribution of stellar masses—the initial mass function—apparently regardless of the initial conditions? A deeper understanding of the formation of stars and planets is needed.\n",
"When stars form in the present Milky Way galaxy they are composed of about 71% hydrogen and 27% helium, as measured by mass, with a small fraction of heavier elements. Typically the portion of heavy elements is measured in terms of the iron content of the stellar atmosphere, as iron is a common element and its absorption lines are relatively easy to measure. The portion of heavier elements may be an indicator of the likelihood that the star has a planetary system.\n",
"In each list, the method used to determine the mass is included to give an idea of uncertainty: Binary stars being more securely determined than indirect methods such as conversion from luminosity, extrapolation from stellar atmosphere models, ... . The masses listed below are the stars’ \"current\" (evolved) mass, not their initial (formation) mass.\n"
] |
if 0.1 amps can be lethal to a human, then why don't i die when touching the contacts of a phone battery, which is 3.8 v and 1500-3200 ma? | When you touch the contacts of a battery, the current that flows through your body is governed by [Ohms law](_URL_0_).
Because your body, and in particular your skin, has a high electrical resitance, the current that results from a 3.8 Volt potential difference is in the range of micro Amperes, which typically will not register with your nervous system.
The number 1500-3200 that you mention is a measure for how much electrical energy can be stored in the battery, and it is usually expressed in milli Ampere hours (mAh). A capacity of 1500 mAh means that your battery is able to sustain a current of 1500 mA for the duration of one hour before it is depleted. Or 750 mA for a duration of two hours. Or 15 mA for a duration of 100 hours. | [
"Voltages greater than 50 V applied across dry unbroken human skin can cause heart fibrillation if they produce electric currents in body tissues that happen to pass through the chest area. The voltage at which there is the danger of electrocution depends on the electrical conductivity of dry human skin. Living human tissue can be protected from damage by the insulating characteristics of dry skin up to around 50 volts. If the same skin becomes wet, if there are wounds, or if the voltage is applied to electrodes that penetrate the skin, then even voltage sources below 40 V can be lethal.\n",
"A high cut-off voltage is more widespread than perhaps assumed. For example, a certain brand of mobile phone that is powered with a single-cell Lithium-ion battery cuts off at 3.3V. The Li‑ion can be discharged to 3V and lower; however, with a discharge to 3.3V (at room temperature), about 92–98% of the capacity is used.\n",
"It is sometimes suggested that human lethality is most common with alternating current at 100–250 volts; however, death has occurred below this range, with supplies as low as 42 volts. Assuming a steady current flow (as opposed to a shock from a capacitor or from static electricity), shocks above 2,700 volts are often fatal, with those above 11,000 volts being usually fatal, though exceptional cases have been noted. According to a Guinness Book of World Records comic, seventeen-year-old Brian Latasa survived a 230,000 volt shock on the tower of an ultra-high voltage line in Griffith Park, Los Angeles on November 9, 1967. A news report of the event stated that he was \"jolted through the air, and landed across the line\", and though rescued by firemen, he suffered burns over 40% of his body and was completely paralyzed except for his eyelids. The shock with the highest voltage reported survived was that of Harry F. McGrew, who came in contact with a 340,000 volt transmission line in Huntington Canyon, Utah.\n",
"Accidental contact with any high voltage supplying sufficient energy may result in severe injury or death. This can occur as a person's body provides a path for current flow, causing tissue damage and heart failure. Other injuries can include burns from the arc generated by the accidental contact. These burns can be especially dangerous if the victim's airway is affected. Injuries may also be suffered as a result of the physical forces experienced by people who fall from a great height or are thrown a considerable distance.\n",
"Importantly, particularly in the case of lithium ion batteries which are used in the vast majority of portable electronics today, a voltage cut-off below 3.2V can lead to chemical instability in the cell, with the result being a reduced battery lifetime. For this reason, electronics manufacturers tend to use higher cut-off voltages, removing the need for consumers to buy battery replacements before other failure mechanisms in a device take effect .\n",
"High-level EMP signals can pose a threat to human safety. In such circumstances, direct contact with a live electrical conductor should be avoided. Where this occurs, such as when touching a Van de Graaf generator or other highly-charged object, care must be taken to release the object and then discharge the body through a high resistance, in order to avoid the risk of a harmful shock pulse when stepping away.\n",
"However, many ESD events occur without a visible or audible spark. A person carrying a relatively small electric charge may not feel a discharge that is sufficient to damage sensitive electronic components. Some devices may be damaged by discharges as small as 30 V. These invisible forms of ESD can cause outright device failures, or less obvious forms of degradation that may affect the long term reliability and performance of electronic devices. The degradation in some devices may not become evident until well into their service life.\n"
] |
How much gas could the world economy save daily by capturing the pump spillage after fueling up? | There was something on Gizmodo about this the other day: _URL_0_
| [
"The world's first industrial extraction of natural gas started at Fredonia, New York, USA in 1825. By 2009, 66 trillion cubic meters (or 8%) had been used out of the total 850 trillion cubic meters of estimated remaining recoverable reserves of natural gas. Based on an estimated 2015 world consumption rate of about 3.4 trillion cubic meters of gas per year, the total estimated remaining economically recoverable reserves of natural gas would last 250 years.\n",
"The World Bank estimates that 134 billion cubic meters of natural gas are flared or vented annually (2010 datum), an amount equivalent to the combined annual gas consumption of Germany and France or enough to supply the entire world with gas for 16 days.\n",
"The global economy consumes approximately 30 billion barrels of oil (1.26 trillion U.S. gallons or 4.75 trillion litres) each year. Numbers of this magnitude are difficult to conceive by most people. The volume occupied by one trillion U.S. gallons is about one cubic mile. Crane felt that a cubic mile would be an easier concept for the general public than a trillion gallons.\n",
"The United States Energy Information Administration predicted in 2006 that world consumption of oil will increase to (mbd) in 2015 and 118 million barrels per day in 2030. With 2009 world oil consumption at 84.4 mbd, reaching the projected 2015 level of consumption would represent an average annual increase between 2009 and 2015 of 2.7% per year.\n",
"According to 2010–12 estimates, proven world reserves of natural gas, from which most LPG is derived, stand at 300 trillion cubic meters (10,600 trillion cubic feet). Added to the LPG derived from cracking crude oil, this amounts to a major energy source that is virtually untapped and has massive potential. Production continues to grow at an average annual rate of 2.2%, virtually assuring that there is no risk of demand outstripping supply in the foreseeable future.\n",
"Initially, the government thought just 17,000 tons of the tanker's 77,000 tons of oil had been lost, and that the remaining 60,000 tons would freeze and not leak from the sunken tanker. In early 2003, it announced that half of the oil had been lost. As of August 2003, the figure had risen to about 63,000 tons, more than eighty percent of the tanker's 77,000 tons of fuel oil have been spilled off Spain's north-west coast.\n",
"The World Bank estimates that over 150 billion cubic metres of natural gas are flared or vented annually. Flared natural gas is worth approximately 30.6 billion dollars and equivalent to 25 percent of the United States' yearly gas consumption or 30 percent of the European Union's annual gas consumption.\n"
] |
How ubiquitous are infectious germs on household surfaces? | I wouldn't call any surface in a home sterile. Go ahead and take swabs of any surface and grow them, you will find growth. Even the dust from our skin contains germs, and that flies everywhere. Wind carries spores, and the air isn't pure since even a virtually airtight home still has it's doors opened and dirty occupants come in. Mold and fungus, bacteria, viruses, and possibly prions are everywhere that I've ever tested. Ahh, but now that I reread you question, I'll rephrase. Germies are everywhere; infectious germies are not. | [
"Scientists are still trying to understand the microorganisms within PM particles and how they are spread through pollutants. Research indicated that many kinds of pathogens and bacteria can be spread through PM smog and cause diseases. For example, Chinese researchers have found that smog in Beijing contains significant amounts of inhalable microbial allergens and pathogenic species, which increase the risk of respiratory diseases. The same study also reported that among all the microorganisms within PM particles, 86.1% are bacteria, 13% eukaryota, 0.8% archaea, and 0.1% viruses. The smog contains a variety of microorganisms such as \"Actinobacteria, Proteobacteria, Chloroflexi, Firmicutes, Bacteroidetes,\" and \"Euryarchaeota.\" Many of these are not harmful to humans, but some pathogenic microorganisms are carried through smog, and their numbers increase as the pollutant level increases.\n",
"Pathogen transmission. Many pathogens are transmitted in the built environment and may also reside in the built environment for some period of time. Good examples include influenza, Norovirus, Legionella, and MRSA. The study of the transmission and survival of these pathogens is a component of studies of microbiomes of the built environment.\n",
"Microorganisms are known to survive on non-antimicrobial in animate ‘touch’ surfaces (e.g., bedrails, over-the-bed trays, call buttons, bathroom hardware, etc.) for extended periods of time. This can be especially troublesome in hospital environments where patients with immunodeficiencies are at enhanced risk for contracting nosocomial infections.\n",
"One study suggested that environmentally relevant levels of polyethylene microbeads had no impact on larvae. Some wastewater treatment plants (WWTPs) in the U.S. and Europe can remove microbeads with an efficiency of greater than 98%, others may not. As such, other sources of microplastic pollution (e.g. microfibers/fibers and car tires) are more likely to be associated with environmental hazards.\n",
"The main sources of infection in the home are people (who are carriers or are infected), foods (particularly raw foods) and water, and domestic animals (in the U.S. more than 50% of homes have one or more pets). Sites that accumulate stagnant water—such as sinks, toilets, waste pipes, cleaning tools, face cloths, etc. readily support microbial growth and can become secondary reservoirs of infection, though species are mostly those that threaten \"at risk\" groups. Pathogens (potentially infectious bacteria, viruses etc.—colloquially called \"germs\") are constantly shed from these sources via mucous membranes, feces, vomit, skin scales, etc. Thus, when circumstances combine, people are exposed, either directly or via food or water, and can develop an infection.\n",
"There is a significant amount of evidence supporting the idea that microbial exposure is linked to allergies or other conditions, although scientific disagreement still exists. Since hygiene is difficult to define or measure directly, surrogate markers are used such as socioeconomic status, income, and diet.\n",
"Microorganisms are known to survive on inanimate touch surfaces for extended periods of time. This can be especially troublesome in hospital environments where patients with immunodeficiencies are at enhanced risk for contracting nosocomial infections (hospital-acquired infection), often with fatal consequences.\n"
] |
Why didn't China save Pakistan from India in 1971? | China wanted to avoid the war in South Asia as much as they could. They wanted Pakistan to come up with a political solution and to end it as soon as possible. Furthermore the Chinese realized that a war with India would not be as easy as it was in 1962.
India had a 'friendship treaty' with the Soviet Union, meaning that "Moscow and New Delhi [were] obliged to consult when either [was] threatened with attack. Since the Russians [were] known to want no part of a conflict that could bring China in on Pakistan's side, they [had] thus suggested that India move with care."
India was advised by the Russians to try its best to not provoke the Chinese into joining the war. And of course this treaty meant that the Russians were now involved in the war (In a limited support and advisory role, but still involved) so the Chinese were also being cautious not to escalate.
One of the reasons why the Chinese were so successful during their war with India was because the Indian army was caught by surprise. This was no longer the case in 1971, as India had fortified the border with China and were preparing for a possible Chinese retaliation. On top of this the Himalayan region was facing heavy snowfall, which would have made a Chinese advance into India much more difficult.
And finally, India's official involvement in the war only lasted 13 days. The Eastern Pakistan forces surrendered less than 2 weeks after Pakistan attacked India. A relatively short time for a war. The Indian army did not continue with its advance into West Pakistan. However, if it did and chose to continue the war, I doubt the Chinese wouldn't have stepped in.
Source: Time. 12/6/1971, Vol. 98 Issue 23, p34. 7p. _URL_0_ | [
"While Western nations did not view Chinese actions favourably because of fear of the Chinese and competitiveness, Pakistan, which had had a turbulent relationship with India ever since the Indian partition, improved its relations with China after the war. Prior to the war, Pakistan also shared a disputed boundary with China, and had proposed to India that the two countries adopt a common defence against \"northern\" enemies (i.e. China), which was rejected by India. China and Pakistan took steps to peacefully negotiate their shared boundaries, beginning on 13 October 1962, and concluding in December of that year. Pakistan also expressed fear that the huge amounts of western military aid directed to India would allow it to threaten Pakistan's security in future conflicts. Mohammed Ali, External Affairs Minister of Pakistan, declared that massive Western aid to India in the Sino-Indian dispute would be considered an unfriendly act towards Pakistan. As a result, Pakistan made efforts to improve its relations with China. The following year, China and Pakistan peacefully settled disputes on their shared border, and negotiated the China-Pakistan Border Treaty in 1963, as well as trade, commercial, and barter treaties. On 2 March 1963, Pakistan conceded its northern claim line in Pakistani-controlled Kashmir to China in favour of a more southerly boundary along the Karakoram Range. The border treaty largely set the border along the MacCartney-Macdonald Line. India's military failure against China would embolden Pakistan to initiate the Second Kashmir War with India. It effectively ended in a stalemate as Calvin states that the Sino-Indian War had caused the previously passive government to take a stand on actively modernising India's military. China offered diplomatic support to Pakistan in this war but did not offer military support. In January 1966, China condemned the Tashkent Agreement between India and Pakistan as a Soviet-US plot in the region. In the Indo-Pakistani War of 1971, Pakistan expected China to provide military support, but it was left alone as India successfully helped the rebels in East Pakistan to found the new nation-state of Bangladesh.\n",
"When the war started, China reproached India for its direct involvement and infiltration in East Pakistan. It disagreed with Pakistani President Yahya Khan's consideration of military options, and criticised East Pakistan Awami League politicians' ties with India. China reacted with great alarm when the prospects of Indian invasion of Pakistan and integration of Pakistan-administered Kashmir into their side of Kashmir, became imminent. US President Nixon encouraged China to mobilise its armed forces along its border with India to discourage the Indian assault, but the Chinese did not respond to this encouragement since the Indian Army's Northern Command was well prepared to guard the Line of Actual Control, and was already engaging and making advances against the Pakistan Army's X Corps in the Line of Control.\n",
"On 3 December, Yahya preemptively attacked the Indian Air Force and Gandhi retaliated, pushing into East Pakistan. Nixon issued a statement blaming Pakistan for starting the conflict and blaming India for escalating it because he favored a cease-fire. The United States was secretly encouraging the shipment of military equipment from Iran, Turkey, and Jordan to Pakistan, reimbursing those countries despite Congressional objections. The US used the threat of an aid cut-off to force Pakistan to back down, while its continued military aid to Islamabad prevented India from launching incursions deeper into the country. Pakistan forces in East Pakistan surrendered on 16 December 1971, leading to the creation of the independent state of Bangladesh.\n",
"Most of China's industry had already been captured or destroyed by Japan, and the Soviet Union refused to allow the United States to supply China through Kazakhstan into Xinjiang as the Xinjiang warlord Sheng Shicai had turned anti-Soviet in 1942 with Chiang's approval. For these reasons, the Chinese government never had the supplies and equipment needed to mount major counter-offensives. Despite the severe shortage of matériel, in 1943, the Chinese were successful in repelling major Japanese offensives in Hubei and Changde.\n",
"Pakistan came under increasing criticism from India, the Soviet Union, Japan, and Europe as the plight of the refugees and their impact on the Indian economy were highlighted by Indira Gandhi in the UN and on a number of global tours. However, the United States and China showed little interest in the crisis and actively opposed aid, intervention or support to the Mukti Bahini(Indian forces) Zulfikar Ali Bhutto at this time led a high-level delegation to Beijing to obtain commitment from China of support in case of Indian intervention while Pakistan pressed at the UN for an International Peacekeeping Force for the India-East Pakistan border. The Pakistani efforts at the UN were however blocked by the Soviet Union in the Security council. India's aid to the Mukti Bahini continued unabated and measured assistance to the Bangladesh Forces, and fighting between the Bangladesh Forces and the Pakistani Forces grew increasingly vicious. Mukti Bahini, Hemayet Bahini, Kaderia Bahini were active around different places of the country.\n",
"As a long-standing ally of Pakistan, the People's Republic of China reacted with alarm to the evolving situation in East Pakistan and the prospect of India invading West Pakistan and Pakistani-controlled Kashmir. Believing that just such an Indian attack was imminent, Nixon encouraged China to mobilise its armed forces along its border with India to discourage it. The Chinese did not, however, respond to this encouragement, because unlike the 1962 Sino-Indian War when India was caught entirely unaware, this time the Indian Army was prepared and had deployed eight mountain divisions to the Sino-Indian border to guard against such an eventuality. China instead threw its weight behind demands for an immediate ceasefire.\n",
"As a long-standing ally of Pakistan, the People's Republic of China reacted with alarm to the evolving situation in East Pakistan and the prospect of India invading West Pakistan and Pakistani-controlled Kashmir. Believing that just such an Indian attack was imminent, Nixon encouraged China to mobilise its armed forces along its border with India to discourage it. The Chinese did not, however, respond to this encouragement, because unlike the 1962 Sino-Indian War when India was caught entirely unaware, this time the Indian Army was prepared and had deployed eight mountain divisions to the Sino-Indian border to guard against such an eventuality. China instead threw its weight behind demands for an immediate ceasefire.\n"
] |
why are brass knuckles called knuckle dusters? | Duster comes from the type of coat, and I suspect that it refers to a covering for your knuckles.
_URL_0_ | [
"Brass knuckles, also sometimes called knuckles, knucks, brass knucks, knucklebusters, knuckledusters, an English punch or a classic, are weapons used in hand-to-hand combat. Brass knuckles are pieces of metal shaped to fit around the knuckles. Despite their name, they are often made from other metals, plastics or carbon fibers. Designed to preserve and concentrate a punch's force by directing it toward a harder and smaller contact area, they result in increased tissue disruption, including an increased likelihood of fracturing the victim's bones on impact. The extended and rounded palm grip also spreads across the attacker's palm the counter-force that would otherwise be absorbed primarily by the attacker's fingers, reducing the likelihood of damage to the attacker's fingers.\n",
"Brass rubbings are created by laying a sheet of paper on top of a brass (actually called \"latten\" - an alloy of brass and nickel) and rubbing the paper with graphite, wax, or chalk, a process similar to rubbing a pencil over a piece of paper placed on top of a coin. In the \"old days\" rubbings were most commonly made using the equivalent of what nowadays is called \"butcher's paper\" [a roll of whitish paper] laid down over the brass and rubbed with \"heelball\", a waxy glob of black crayon once used to shine shoes. Now most brass rubbers purchase special paper rolls of heavy duty black velvety material, and the crayons are gold, silver or bronze (other colours are available).\n",
"Some brass knuckles have rounded rings, which increase the impact of blows from moderate to severe damage. Other instruments (not generally considered to be \"brass knuckles\" or \"metal knuckles\" \"per se\") may have spikes, sharp points and cutting edges. These devices come in many variations and are called by a variety of names, including \"knuckle knives.\"\n",
"Brass is susceptible to stress corrosion cracking, especially from ammonia or substances containing or releasing ammonia. The problem is sometimes known as season cracking after it was first discovered in brass cartridges used for rifle ammunition during the 1920s in the British Indian Army. The problem was caused by high residual stresses from cold forming of the cases during manufacture, together with chemical attack from traces of ammonia in the atmosphere. The cartridges were stored in stables and the ammonia concentration rose during the hot summer months, thus initiating brittle cracks. The problem was resolved by annealing the cases, and storing the cartridges elsewhere.\n",
"When polishing brass (a softer metal) there are often minute marks in the metal caused by impurities. To smooth out the finer marks, the surface is polished with a very fine (600) grit, copper plated, then buffed to a mirror finish with an airflow mop.\n",
"Brass rubbing was originally a largely British enthusiasm for reproducing onto paper monumental brasses – commemorative brass plaques found in churches, usually originally on the floor, from between the thirteenth and sixteenth centuries. The concept of recording textures of things is more generally called making a rubbing. What distinguishes rubbings from frottage is that rubbings are meant to reproduce the form of something being transferred, whereas frottage is usually only intended to use a general texture.\n",
"BULLET::::- Brass knuckles: Sometimes abbreviated to brass knucks or just knucks. Brass knuckles, while seen as a cheap shot in traditional professional wrestling, these are a common weapon in hardcore wrestling.\n"
] |
Was Atahualpa immune to smallpox? | Could you elaborate a bit? Are you asking if he contracted smallpox prior to Cajamarca? | [
"In the years between 1524 and 1526, the European germ smallpox, introduced from the conquistadores in Panama and preceding the Spanish conquerors in Peru through transmission among natives, had swept through the Inca Empire. Smallpox caused the death of the Incan ruler Huayna Capac as well as most of his family including his heir, caused the fall of the Incan political structure and contributed to the civil war between the brothers Atahualpa and Huáscar. Taking advantage of this, Pizarro carried out a \"coup d'état\". On November 16, 1532, while the Atahualpa's victorious army was in an unarmed celebration in Cajamarca, the Spanish lured Inca Atahualpa into a trap during the Battle of Cajamarca. The well-armed 168 Spaniards killed thousands of barely armed Inca soldiers and captured the newly minted Inca ruler, causing a great consternation among the natives and conditioning the future course of the fight. When Huáscar was killed, the Spanish tried and convicted Atahualpa of the murder, executing him by strangulation.\n",
"The introduction of smallpox among the Aztecs has been attributed to an African slave (by the name of Francisco Eguía, according to one account) but this has been disputed. From May to September, smallpox spread slowly to Tepeaca and Tlaxcala, and to Tenochtitlán by the fall of 1520. At this time, Cortes was returning to conquer the city after being thrown out on the Noche Triste.\n",
"Smallpox was an unknown disease not only in Mexico, but in the Americas, before the arrival of Europeans. It was introduced to Mexican lands by the Spanish and played a significant role in the downfall of the Aztec Empire. Hernán Cortés departed from Cuba and arrived in Mexico in 1521, sent to start trade relations on the Veracruz Coast. However, he disobeyed the Cuban governor and began to invade the mainland. The governor sent Pánfilo de Narváez after Cortés. Narvaez’s forces had at least one active case of smallpox, and when the Narvaez expedition stopped at Cozumel and Veracruz in 1520, the disease gained a foothold in the region.\n",
"There are no credible descriptions of smallpox-like disease in the Americas before the westward exploration by Europeans in the 15th century CE. Smallpox was introduced into the Caribbean island of Hispaniola in 1509, and into the mainland in 1520, when Spanish settlers from Hispaniola arrived in Mexico, inadvertently carrying smallpox with them. Because the native Amerindian population had no acquired immunity to this new disease, their peoples were decimated by epidemics. Such disruption and population losses were an important factor in the Spanish achieving conquest of the Aztecs and the Incas. Similarly, English settlement of the east coast of North America in 1633 in Plymouth, Massachusetts was accompanied by devastating outbreaks of smallpox among Native American populations, and subsequently among the native-born colonists. Case fatality rates during outbreaks in Native American populations were as high as 80–90%. Smallpox was introduced into Australia in 1789 and again in 1829. Although the disease was never endemic on the continent, it was the principal cause of death in Aboriginal populations between 1780 and 1870.\n",
"Even with the horses, bloodhounds, gunpowder, and steel, Cortés had a tough time with the Aztecs; Smallpox on the other hand was able to spread to those who have not been in contact with it yet, killing off many people regardless of being rich or poor; people high and low were being infected. Thus the introduction of smallpox that Cortes and his men brought with them, was the significant impact to the fall of the Aztec Empire. As most of the Spaniards have built up somewhat of an immunity to this disease; having brought it. \n",
"The isolated position of the Tsilhqot’in may have protected them from the first of the smallpox epidemics, which spread up from Mexico in the 1770s. They may have been spared the smallpox epidemic of 1800 and the measles of the 1840s. Furniss in \"The Burden of History\" states that \"there is no direct evidence that these smallpox epidemics reached the central interior of British Columbia or the Secwepemc, Carrier, or Tsilhqot'in\". However, in the epidemic of 1836–38, the disease spread to Ootsa Lake and killed an entire Carrier band. Oral history of the bands has continued to recount the effects of the many deaths in these epidemics.\n",
"Chicken pox and measles, endemic but rarely fatal among Europeans (long after being introduced from Asia), often proved deadly to Native Americans. Smallpox epidemics often immediately followed European exploration and sometimes destroyed entire village populations. While precise figures are difficult to determine, some historians estimate that at least 30% (and sometimes 50% to 70%) of some Native populations died after first contact due to Eurasian smallpox. One element of the Columbian exchange suggests explorers from the Christopher Columbus expedition contracted syphilis from indigenous peoples and carried it back to Europe, where it spread widely. Other researchers believe that the disease existed in Europe and Asia before Columbus and his men returned from exposure to indigenous peoples of the Americas, but that they brought back a more virulent form.\n"
] |
How can anything ever reach any event horizon ? | According to an external observer, yes, that's completely correct. According to the poor bloke falling into the black hole, there's nothing special about the event horizon, just a continuation of the same old impending sense of utter doom. | [
"There is an event horizon in the universe where light (and therefore any information) cannot and will never be able to reach an object, because the cosmic acceleration outpaces the speed of light: the cosmological comoving horizon. If the object accelerates in one direction, a similar event horizon is produced: the Rindler horizon. Anything beyond these horizons is outside the observable universe, and therefore can't affect the object at the center of the Rindler space.\n",
"In astrophysics, an event horizon is a boundary beyond which events cannot affect an observer on the opposite side of it. An event horizon is most commonly associated with black holes, where gravitational forces are so strong that light cannot escape.\n",
"In the case of a horizon perceived by a uniformly accelerating observer in empty space, the horizon seems to remain a fixed distance from the observer no matter how its surroundings move. Varying the observer's acceleration may cause the horizon to appear to move over time, or may prevent an event horizon from existing, depending on the acceleration function chosen. The observer never touches the horizon and never passes a location where it appeared to be.\n",
"In cosmology, the event horizon of the observable universe is the largest comoving distance from which light emitted \"now\" can ever reach the observer in the future. This differs from the concept of particle horizon, which represents the largest comoving distance from which light emitted in the \"past\" could have reached the observer at a given time. For events beyond that distance, light has not had time to reach our location, even if it were emitted at the time the universe began. How the particle horizon changes with time depends on the nature of the expansion of the universe. If the expansion has certain characteristics, there are parts of the universe that will never be observable, no matter how long the observer waits for light from those regions to arrive. The boundary past which events cannot ever be observed is an event horizon, and it represents the maximum extent of the particle horizon.\n",
"A misconception concerning event horizons, especially black hole event horizons, is that they represent an immutable surface that destroys objects that approach them. In practice, all event horizons appear to be some distance away from any observer, and objects sent towards an event horizon never appear to cross it from the sending observer's point of view (as the horizon-crossing event's light cone never intersects the observer's world line). Attempting to make an object near the horizon remain stationary with respect to an observer requires applying a force whose magnitude increases unboundedly (becoming infinite) the closer it gets.\n",
"In this equation, \"a\" is the scale factor, \"c\" is the speed of light, and \"t\" is the age of the Universe. If (i.e., points arbitrarily as far away as can be observed), then no event horizon exists. If , a horizon is present.\n",
"One of the best-known examples of an event horizon derives from general relativity's description of a black hole, a celestial object so massive that no nearby matter or radiation can escape its gravitational field. Often, this is described as the boundary within which the black hole's escape velocity is greater than the speed of light. However, a more accurate description is that within this horizon, all lightlike paths (paths that light could take) and hence all paths in the forward light cones of particles within the horizon, are warped so as to fall farther into the hole. Once a particle is inside the horizon, moving into the hole is as inevitable as moving forward in time, and can actually be thought of as equivalent to doing so, depending on the spacetime coordinate system used.\n"
] |
why can't the us (or any country in general) alleviate their external debt by collecting their external credit? | When you are talking about debt on a governmental scale, that is a highly structured, desirable investment option.
It is not like when you borrow fifty bucks to a friend and you can call up tomorrow and demand your money back. When money is loaned to the government, it is in the form of a bond. A bond has very specific terms of agreement, interest and payment times. You cannot collect early on a bond (you can sell it to someone else though if you need cash immediately). Everybody involved has to stick to the terms. It cannot be repaid early, but it can also not be demanded back early.
What the US government could do, theoretically, is cancel out a lot of those bonds because the US government is one of the biggest holders of US bonds. Think of it as the right hand owing the left hand money.
Of course the US government does not want to do this, because there is nothing wrong with government debt, at least not at the level it is at in the USA. Interest on government bonds is low, confidence in the US economy is high among investors. The US government has never missed a payment of interest on any of their outstanding bonds. Right now, again because the interest is so low, pretty much everything the USA government does with the money it borrow will make them more money than they have to pay back. | [
"Governments create debt by issuing government bonds and bills. Less creditworthy countries sometimes borrow directly from a supranational organization (e.g. the World Bank) or international financial institutions.\n",
"Since a sovereign government, by definition, controls its own affairs, it cannot be obliged to pay back its debt. Nonetheless, governments may face severe pressure from lending countries. In a few extreme cases, a major creditor nation, before the establishment of the UN Charter Article 2 (4) prohibiting use of force by states, made threats of war or waged war against a debtor nation for failing to pay back debt to seize assets to enforce its creditor's rights. For example, in 1882, the United Kingdom invaded Egypt. Other examples include the United States' \"gunboat diplomacy\" in Venezuela in the mid-1890s and the United States occupation of Haiti beginning in 1915.\n",
"The World Bank and the IMF hold that “a country can be said to achieve external debt sustainability if it can meet its current and future external debt service obligations in full, without recourse to debt rescheduling or the accumulation of arrears and without compromising growth.” According to these two institutions, external debt sustainability can be obtained by a country “by bringing the net present value (NPV) of external public debt down to about 150 percent of a country’s exports or 250 percent of a country’s revenues.” High external debt is believed to have harmful effects on an economy.\n",
"The World Bank and IMF hold that \"a country can be said to achieve external debt sustainability if it can meet its current and future external debt service obligations in full, without recourse to debt rescheduling or the accumulation of arrears and without compromising growth\". According to these two institutions, \"bringing the net present value (NPV) of external public debt down to about 150 percent of a country's exports or 250 percent of a country's revenues\" would help eliminating this \"critical barrier to longer-term debt sustainability\". High external debt is believed to be harmful for the economy.\n",
"These loan conditions ensure that the borrowing country will be able to repay the IMF and that the country will not attempt to solve their balance-of-payment problems in a way that would negatively impact the international economy. The incentive problem of moral hazard—when economic agents maximise their own utility to the detriment of others because they do not bear the full consequences of their actions—is mitigated through conditions rather than providing collateral; countries in need of IMF loans do not generally possess internationally valuable collateral anyway.\n",
"The debtor nations put strong pressure on the U.S. in the 1920s to forgive the debts, or at least reduce them. The American government refused. Instead, U.S. banks began making large loans to the nations of Europe. Thus, debts (and reparations) were being paid only by augmenting old debts and piling up new ones. In the late 1920s, and particularly after the American economy began to weaken after 1929, the European nations found it much more difficult to borrow money from the U.S. At the same time, high U.S. tariffs were making it much more difficult for them to sell their goods in U.S. markets. Without any source of revenue from foreign exchange to repay their loans, they began to default.\n",
"As of 2012 the country has huge debts, but the overseas Filipino workers (OFWs) foreign exchange remittances have kept the country's debts from increasing to critical levels. Not only is foreign debt being paid with these remittances but they are also used as collateral for new loans. Furthermore, they help to improve the balance of payments and reduce the trade gap. Foreign exchange reserves mainly come from labor migration and OFW remittances have surpassed the export sector in producing foreign exchange. For this reason the government is supporting overseas deployment of the labor force which has reached around one million Filipinos per year.\n"
] |
At what level does the circulatory system of each indivdual start to differ? | Most of the major named arteries follow the same course, but there's a great deal of variation. There isn't some set point at which they occur (it's not like you can say '3 branches off the aorta, things start to diverge'), but generally smaller vessels and areas with a lot of anastamoses tend to feature more variability. One common and clinically relevant example is in the coronary arteries of the heart - the posterior descending is usually a branch off the right coronary, but can also branch off the left circumflex, or both. Another common site of variation is in the circle of Willis, which supplies the brain. Capillaries pretty much just go where they are needed, and don't necessarily follow a set path. | [
"A circulatory anastomosis is a connection (an anastomosis) between two blood vessels, such as between arteries (arterio-arterial anastomosis), between veins (veno-venous anastomosis) or between an artery and a vein (arterio-venous anastomosis). Anastomoses between arteries and between veins result in a multitude of arteries and veins, respectively, serving the same volume of tissue. Such anastomoses occur normally in the body in the circulatory system, serving as backup routes for blood to flow if one link is blocked or otherwise compromised, but may also occur pathologically.\n",
"In the central circulatory system, the blood moves anteriorly from the tip of the abdomen to the front of the thorax through a sinus enveloping the alimentary canal, and posteriorly through a ventral blood vessel. The ventral vessel and the sinus communicate with each other by segmentally arranged ring vessels, and by a dorsal vessel, a transverse vessel, and a pair of circumesophageal vessels situated at the anterior end of the thorax. The dorsal vessel in some of the larger serpulids, like \"Serpula\", possesses a valve and a muscular sphincter, probably to prevent backflow of blood from the transverse vessel.\n",
"The circulatory system is made up of two circulations (pulmonary and systemic) situated in series between the right ventricle (RV) and left ventricle (LV). Balance is achieved, in large part, by the Frank–Starling mechanism. For example, if systemic venous return is suddenly increased (e.g., changing from upright to supine position), right ventricular preload increases leading to an increase in stroke volume and pulmonary blood flow. The left ventricle experiences an increase in pulmonary venous return, which in turn increases left ventricular preload and stroke volume by the Frank–Starling mechanism. In this way, an increase in venous return can lead to a matched increase in cardiac output.\n",
"The peripheral circulatory system has the following components: the two branchial vessels and their branches in the crown; the periesophageal vascular plexuses; the vessels of the collar and lips; the vessels supplying the body wall, thoracic membrane, and parapodia. The single vessels in each radiole of the branchial crown, and the vessels of opercula, are all branches of the two branchial vessels.\n",
"The endodermal cloaca is divided into a dorsal and a ventral part by means of a partition, the urorectal septum, which grows downward from the ridge separating the allantois from the cloacal opening of the intestine and ultimately fuses with the cloacal membrane and divides it into an anal and a urogenital part. The dorsal part of the cloaca forms the rectum, and the anterior part of the urogenital sinus and bladder. The urorectal septum eventually becomes part of the perineal body.\n",
"Unlike peristalsis, which predominates in the esophagus, segmentation contractions occur in the large intestine and small intestine, while predominating in the latter. While peristalsis involves one-way motion in the caudal direction, segmentation contractions move chyme in both directions, which allows greater mixing with the secretions of the intestines. Segmentation involves contractions of the circular muscles in the digestive tract, while peristalsis involves rhythmic contractions of the longitudinal muscles in the gastrointestinal tract. Unlike peristalsis, segmentation actually can slow progression of chyme through the system.\n",
"In arthropods, the open circulatory system is a system in which a fluid in a cavity called the hemocoel bathes the organs directly with oxygen and nutrients and there is no distinction between blood and interstitial fluid; this combined fluid is called hemolymph or haemolymph. Muscular movements by the animal during locomotion can facilitate hemolymph movement, but diverting flow from one area to another is limited. When the heart relaxes, blood is drawn back toward the heart through open-ended pores (ostia).\n"
] |
How did medieval Russia interact with its nomadic Asian neighbors prior to the Mongol invasion? | I have a great deal of information on the subject, but I'm a little busy looking for information on another subject right now. Reply to me and I'll get back to you after I've gotten some work done on my paper.
Here's the real quick and dirty of it: Russian principalities interacted with steppe nomads a lot like how the nomads interacted with each other. There was a lot of raiding back and forth, some trade and diplomacy, and even intermarriage. Things were complicated by the fact that the Rus' were predominantly Christian and the steppe nomads were mostly Muslim. Russian writers of the time characterized any conflict, including the most bold-faced "for profit" raids, as holy war against infidels, and the trading and intermarriage was ignored as much as possible. | [
"Mongol invasion of Rus can be divided in two phases. In winter of 1237-38 they conquered Northern Russia (principalities of Ryazan and Vladimir-Suzdal) with the exception of Novgorod, but in spring of 1238 retreated back to Wild Fields. The second campaign, aimed to Southern Russia (principalities of Chernigov and Kiev) came in 1239.\n",
"The Mongol invasions of 1236-1241 left the Russian principalities subjugated by the Golden Horde. In the 13th-15th centuries, the Khan of the Golden Horde appointed the Great Prince, who in the 14th century resided in Moscow. In the 13th century the medieval Rus' consisted of a set of relatively small and weak principalities, fighting and making alliances against each other. The larger states (like the Grand Duchy of Moscow and the Republic of Novgorod) progressively conquered or absorbed the smaller ones. One bigger principality, the Grand Duchy of Moscow, grew due to a series of clever policies and became the biggest one in central Rus'. In 1380 Dmitry Donskoy, the prince of Moscow, even managed to fight the troops of Golden Horde in the Battle of Kulikovo and win. Whereas formally Moscow remained dependent on the Horde, and the Khan needed to approve position of the Prince, the Grand Duchy of Moscow had become a major regional power, and the Moscow princes aimed to conquer the remaining lands around Moscow and to append them to their Grand Duchy.\n",
"During what was the late Middle Ages of Western Europe, the Caucasus was invaded by Mongols and their Turkic vassals. The first appearance of Mongol troops in the Caucasus was an arrival of scouts in 1220-1222. Kypchak Turkic peoples - some of which becoming future affiliates of Genghis Khan - had been invading and settling areas further and further South and West (a process that had was continuing since the fall of the Khazars), including the fertile river valleys of the Terek and the Kuban. In the 1230s, the Mongols gained rule over the Kypchaks, and turned them into vassals. \n",
"The Mongol invasion of Europe in the 13th century was the conquest of Europe by the Mongol Empire, by way of the destruction of East Slavic principalities, such as Kiev and Vladimir. The Mongol invasions also occurred in Central Europe, which led to warfare among fragmented Poland, such as the Battle of Legnica (9 April 1241) and in the Battle of Mohi (11 April 1241) in the Kingdom of Hungary.\n",
"In 1223, the expanding Mongol Empire defeated an group of semi- allied Russian city states, at the time known as Rus, at the Kalka River using their famous tactic of the feigned retreat under Subutai and Jebe. This was part of their great cavalry raid to explore the lands beyond their knowledge under the direction of Genghis Khan. \n",
"The impact of the Mongol invasion on the territories of Kievan Rus' was uneven. The advanced city culture was almost completely destroyed. As older centers such as Kiev and Vladimir never recovered from the devastation of the initial attack, the new cities of Moscow, Tver and Nizhny Novgorod began to compete for hegemony in the Mongol-dominated Russia. Although a Russian army defeated the Golden Horde at Kulikovo in 1380, Mongol domination of the Russian-inhabited territories, along with demands of tribute from Russian princes, continued until about 1480.\n",
"In 1237, the Mongols began their invasion of Rus by conquering the northern principalities of Ryazan and Vladimir-Suzdal. In 1239, they advanced against southern Rus, capturing the cities of Pereyaslav and Chernihiv.\n"
] |
Is it possible that psychedelics like psilocybin increase the spectrum of colors that we can see? | It really doesn't physically change how many colors we can see or how we hear. Your visual receptors have a specific range of wavelengths that they can detect, same with your ears. Taking a psychedelic won't change this fact. Psychedelics change your brain chemistry in certain ways that can make you see colors you wouldn't normally see or hear things you wouldn't normally hear, but this is due strictly to chemical balances in your brain. You aren't "seeing" these new colors with your eyes; your visual cortex is creating them while you are under the influence of the drug. | [
"Psychedelic experience includes the full range of mystical or religious experiential phenomena. Two scientific studies have concluded that psilocybin (a typical psychedelic compound that occurs naturally in psilocybin mushrooms) reliably triggers mystical-type experiences. The more recent study at Johns Hopkins University identified mystical experiences by means of several questionnaires designed to categorise altered state 'non-ordinary' experiences, including one questionnaire called 'the mysticism scale'.\n",
"A debate has been going on about whether psilocybin is an ethical, or even safe, treatment for depression and other mental illnesses such as anxiety. In comparison to other drugs, psychedelics in general are relatively harmless physiologically. Many of the currently known psychedelics, including psilocybin, are classified as having no accepted medical use in the US.\n",
"In a 25-year follow-up to the experiment, all of the subjects given psilocybin described their experience as having elements of \"a genuine mystical nature and characterized it as one of the high points of their spiritual life\". Psychedelic researcher Rick Doblin considered Pahnke's original study partially flawed due to incorrect implementation of the double-blind procedure, and several imprecise questions in the mystical experience questionnaire. Nevertheless, Doblin said that Pahnke's study cast \"a considerable doubt on the assertion that mystical experiences catalyzed by drugs are in any way inferior to non-drug mystical experiences in both their immediate content and long-term effects\". A similar sentiment was expressed by clinical psychologist William A. Richards, who in 2007 stated \"[psychedelic] mushroom use may constitute one technology for evoking revelatory experiences that are similar, if not identical, to those that occur through so-called spontaneous alterations of brain chemistry.\"\n",
"Mescaline induces a psychedelic state similar to those produced by LSD and psilocybin, but with unique characteristics. Subjective effects may include altered thinking processes, an altered sense of time and self-awareness, and closed- and open-eye visual phenomena.\n",
"Psilocybin mushrooms possess psychedelic properties. Commonly known as \"magic mushrooms\" or shrooms\", they are openly available in smart shops in many parts of the world, or on the black market in those countries that have outlawed their sale. Psilocybin mushrooms have been reported as facilitating profound and life-changing insights often described as mystical experiences. Recent scientific work has supported these claims, as well as the long-lasting effects of such induced spiritual experiences.\n",
"While many recent studies have concluded that psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance, not all the medical community is on board. Paul R. McHugh, formerly director of the Department of Psychiatry and Behavioral Science at Johns Hopkins, responded as follows in a book review: \"The unmentioned fact in \"The Harvard Psychedelic Club\" is that LSD, psilocybin, mescaline, and the like produce not a “higher consciousness” but rather a particular kind of “lower consciousness” known well to psychiatrists and neurologists—namely, “toxic delirium.”\" In response to Dr. McHugh’s denial that the mystical experience leads to insight, Michael Pollan points to Roland Griffiths, Johns Hopkins researcher and author of many studies finding that the experiences of many of the participants have actually involved substantial and sustained personal meaning bringing enduring positive changes in psychological functioning. According to Pollan, Griffiths admits that those taking psilocybin may be encountering a temporary psychosis, but notes that the patients McHugh describes are unlikely to report years later of their experience: \"Wow, that was one of the greatest and most meaningful experiences of my life\". Such responses argue that it is not appropriate to automatically equate a psilocybin-induced experience of profound insight with superficially similar experiences of psychiatric patients (characterized as mere toxic delirium), when it is only the “insight” reached in the psilocybin experience that is reported to often result in profound, beneficial and enduring life changes for the person.\n",
"Computer art has allowed for an even greater and more profuse expression of psychedelic vision. Fractal generating software gives an accurate depiction of psychedelic hallucinatory patterns, but even more importantly 2D and 3D graphics software allow for unparalleled freedom of image manipulation. Much of the graphics software seems to permit a direct translation of the psychedelic vision. The \"digital revolution\" was indeed heralded early on as the \"New LSD\" by none other than Timothy Leary. \n"
] |
is there a link between diet soda consumption (i.e. aspartame) and cancer? if not, why does the general public continue to think there is. | There are biased, non-peer-reviewed studies that make this link, but there's no real evidence of any link. Unfortunately some people like to latch on to any study that promotes FUD without considering any of the facts. | [
"In a report released on 10 December 2013, the EFSA said that, after an extensive examination of evidence, it ruled out the \"potential risk of aspartame causing damage to genes and inducing cancer,\" and deemed the amount found in diet sodas an amount safe to consume.\n",
"Coca-Cola has been under fire since 2015 when emails revealed that funding for scientific studies sought to influence research to be more favorable to soda. Research funded by soda companies are 34 times more likely to find soda has no significant health impacts on obesity or diabetes.\n",
"In 1981, human epidemiological analysis by Richard Doll and Richard Peto indicated that smoking caused 30% of cancers in the US. Diet is also thought to cause a significant number of cancer, and it has been estimated that around 32% of cancer deaths may be avoidable by modification to the diet. Mutagens identified in food include mycotoxins from food contaminated with fungal growths, such as aflatoxins which may be present in contaminated peanuts and corn; heterocyclic amines generated in meat when cooked at high temperature; PAHs in charred meat and smoked fish, as well as in oils, fats, bread, and cereal; and nitrosamines generated from nitrites used as food preservatives in cured meat such as bacon (ascobate, which is added to cured meat, however, reduces nitrosamine formation). Overly-browned starchy food such as bread, biscuits and potatoes can generate acrylamide, a chemical shown to cause cancer in animal studies. Excessive alcohol consumption has also been linked to cancer; the possible mechanisms for its carcinogenicity include formation of the possible mutagen acetaldehyde, and the induction of the cytochrome P450 system which is known to produce mutagenic compounds from promutagens.\n",
"Studies on laboratory rats during the early 1970s linked high volumes of cyclamate and saccharin with the development of bladder cancer. As a result, the United States Congress mandated that further studies of saccharin be performed and required that all food containing saccharin bear a label warning that the sweetener had been shown to cause cancer in laboratory animals. Despite this, Tab remained commercially successful, and was the best-selling diet soda in 1982. In May 1984, Coca-Cola introduced Nutrasweet into the Tab formula, which maligned a significant portion of its market, and resulted in numerous consumer complaints regarding a perceived change in flavor.\n",
"While many dietary recommendations have been proposed to reduce the risk of cancer, few have significant supporting scientific evidence. Obesity and drinking alcohol have been correlated with the incidence and progression of some cancers. Lowering the drinking of beverages sweetened with sugar is recommended as a measure to address obesity. A diet low in fruits and vegetables and high in red meat has been implicated but not confirmed, and the effect may be small for well-nourished people who maintain a healthy weight.\n",
"Clinical studies investigating the relationship between flavonoid consumption and cancer prevention/development are conflicting for most types of cancer, probably because most studies are retrospective in design and use a small sample size. Two apparent exceptions are gastric carcinoma and smoking-related cancers. Dietary flavonoid intake is associated with reduced gastric carcinoma risk in women, and reduced aerodigestive tract cancer risk in smokers.\n",
"While many dietary recommendations have been proposed to reduce cancer risks, the evidence to support them is not definitive. The primary dietary factors that increase risk are obesity and alcohol consumption. Diets low in fruits and vegetables and high in red meat have been implicated but reviews and meta-analyses do not come to a consistent conclusion. A 2014 meta-analysis find no relationship between fruits and vegetables and cancer. Coffee is associated with a reduced risk of liver cancer. Studies have linked excess consumption of red or processed meat to an increased risk of breast cancer, colon cancer and pancreatic cancer, a phenomenon that could be due to the presence of carcinogens in meats cooked at high temperatures. In 2015 the IARC reported that eating processed meat (e.g., bacon, ham, hot dogs, sausages) and, to a lesser degree, red meat was linked to some cancers.\n"
] |
what determines the strength of someones vocal chords, e.g. how loud they are? | Loudness comes much more from breathing than from your vocal chords. The more air you can push past them, the louder you can be.
Vocal coaches will tell you to practice breathing from the diaphragm which isn't as easy or natural as it may seem. There are tons of videos on YouTube demonstrating this. Basically try taking a deeper breath than usual and then exhale, pushing more air out of your lungs when you speak or sing, and you will notice your volume go up. | [
"The perceived pitch of a person's voice is determined by a number of different factors, most importantly the fundamental frequency of the sound generated by the larynx. The fundamental frequency is influenced by the length, size, and tension of the vocal folds. This frequency averages about 125 Hz in an adult male, 210 Hz in adult females, and over 300 Hz in children. Depth-kymography is an imaging method to visualize the complex horizontal and vertical movements of vocal folds.\n",
"The physical limits of muscular strength of the internal thyroarytenoids or vocalis muscle are being approached. To sing or speak above this pitch level the voice must adopt a new phonatory pattern to change registers.\n",
"The sound of each individual's voice is entirely unique not only because of the actual shape and size of an individual's vocal cords but also due to the size and shape of the rest of that person's body, especially the vocal tract, and the manner in which the speech sounds are habitually formed and articulated. (It is this latter aspect of the sound of the voice that can be mimicked by skilled performers.) Humans have vocal folds that can loosen, tighten, or change their thickness, and over which breath can be transferred at varying pressures. The shape of chest and neck, the position of the tongue, and the tightness of otherwise unrelated muscles can be altered. Any one of these actions results in a change in pitch, volume, timbre, or tone of the sound produced. Sound also resonates within different parts of the body, and an individual's size and bone structure can affect somewhat the sound produced by an individual.\n",
"Due to its small size, the larynx acts as a resonator only for high frequencies. Research indicates that one of the desirable attributes of good vocal tone is a prominent overtone lying between 2800 and 3200 hertz, with male voices nearer the lower limit and female voices nearer the upper. This attribute is identified as brilliance, or more frequently as \"ring\" or the \"singer's formant\", as fully described by Sundberg. There are several areas in or adjacent to the larynx which might resonate such a high pitch. Among them are the collar of the larynx, the ventricles of Morgani, the vallecula, and the pyriform sinuses. The larynx is not under conscious control, but whatever produces \"ring\" can be encouraged indirectly by awareness on the part of the student and the teacher of the sounds which contain it.\n",
"Adult men and women typically have different sizes of vocal fold; reflecting the male-female differences in larynx size. Adult male voices are usually lower-pitched and have larger folds. The male vocal folds (which would be measured vertically in the opposite diagram), are between 17 mm and 25 mm in length. The female vocal folds are between 12.5 mm and 17.5 mm in length.\n",
"Physically, men's vocal folds and vocal tracts are longer than those of women, which produces a lower fundamental frequency and closer spacing of formant frequencies in men. These differences are not fully clear from an evolutionary perspective; However, it has been suggested that voice pitch is linked to male dominance competition. Current research on male voice pitch suggests that lower pitch is perceived as increasing dominance. Lower pitch voices also tend to be indicators of physical and social dominance. Other vocalization signals include loud rapid speaking tempo and clear articulation.\n",
"Males and females have different vocal fold sizes. Adult male voices are usually lower pitched due to longer and thicker folds. The male vocal folds are between 1.75 cm and 2.5 cm (approx 0.75\" to 1.0\") in length, while female vocal folds are between 1.25 cm and 1.75 cm (approx 0.5\" to 0.75\") in length. The vocal folds of children are much shorter than those of adult males and females. The difference in vocal fold length and thickness between males and females causes a difference in vocal pitch. Additionally, genetic factors cause variations between members of the same sex, with males' and females' voices being categorized into voice types.\n"
] |
why does japan have such a high conviction rate? | Fewer rules against how evidence is gathered, so the discovery and investigation parts of the system are faster with fewer pieces of damning evidence thrown out due to "procedural" or "paperwork" errors. | [
"Japan has a conviction rate of over 99%. In several cases, courts have acknowledged confessions were forced and released those imprisoned. To combat this, a law was passed in 2016 requiring some interrogations to be videotaped. However, this only applies to people accused of serious crimes, such as murder, arson and kidnapping, which make up only 3% of cases. In common law countries which practice trial by jury, a high conviction rate is seen as an indication that defendants are not receiving a fair trial. In civil law countries, where a magistrate decides the verdict, it is common because both the defense and the prosecutor can reliably predict the outcome of the trial. Japan also practices the death penalty, to which the U.N. objects, as do several prominent NGOs and the European Union (see Capital punishment in Japan).\n",
"The most likely reason why the Japanese conviction rate is so high is that prosecutors have a broad discretion to prosecute or not, taking into account many factors (similar to sentencing factors in Western countries). The prosecutors may decide, for example, not to prosecute someone even if there is sufficient evidence to win at trial, because of the circumstances of the crime or accused. Article 248 of the Japanese Code of Criminal Procedure states: \"Where prosecution is deemed unnecessary owing to the character, age, environment, gravity of the offense, circumstances or situation after the offense, prosecution need not be instituted.\" Thus, prosecutors in Japan have a very broad discretion in the decision to prosecute or not.\n",
"Prosecutors in Japan do not generally go to trial unless they have overwhelming evidence of guilt. Because of this tendency, they decline to prosecute nearly a quarter of all cases. For those that go to trial, Japanese prosecutors hold a conviction record of about 98%. These patterns contribute to public perceptions of the infallibility of the police and the legal system, and the perception that if a person is arrested, he or she must be guilty of the crime.\n",
"In the matter relating to Japanese prosecutors being extremely cautious, the paper found ample evidence for it. In Japan, 99.7% of all the cases brought to court resulted in conviction, while in the U.S. the figure is 88%. According to a cited research, in the U.S. the accused contest guilt in 22% of federal cases and 11% of state cases, while in Japan, the ratio is modestly less. The paper attributes this difference to greater predictability of the outcome in Japanese cases. This is due to two reasons. One is that it is the judge rather than the jury who determines the verdict. As judges \"have seen it all before\" and the lawyers on both sides \"have seen them seeing it\", as they can read the judge's previous ruling (which includes written reasoning for the previous verdict), the way that the judge thinks and argues is very predictable.\n",
"In Japan, the criminal justice system has a conviction rate that exceeds 99%, including guilty plea cases. This has been attributed to low prosecutorial budgets impelling understaffed prosecutors to bring only the most obviously guilty defendants to trial.\n",
"Japanese law does not define those convicted in the post-1945 trials as criminals, despite the fact that Japan's governments have accepted the judgments made in the trials, and in the Treaty of San Francisco (1952). This is because the treaty does not mention the legal validity of the tribunal. Had Japan certified the legal validity of the war crimes tribunals in the San Francisco Treaty, the war crimes would have become open to appeal and overturning in Japanese courts. This would have been unacceptable in international diplomatic circles. Current Prime Minister Shinzō Abe has advocated the position that Japan accepted the Tokyo tribunal and its judgements as a condition for ending the war, but that its verdicts have no relation to domestic law. According to this view, those convicted of war crimes are not criminals under Japanese law.\n",
"Twenty-eight Japanese military and political leaders were charged with Class A crimes, and more than 5,700 Japanese nationals were charged with Class B and C crimes, mostly entailing prisoner abuse. China held 13 tribunals of its own, resulting in 504 convictions and 149 executions.\n"
] |
why do some people get annoyed when you say america instead of the united states? | Depends on what you mean by 'most people.' It's that attitude that annoys people. I don't have a problem with it myself, and am used to saying it, but that's because I'm from the U.S. Someone from outside the U.S. but who is also from 'the Americas' might take offense that we are claiming everything as our own like colonialists or ignoring everyone else like elitists , and I've been told that the rest of the world hates the U.S. for similar reasons. | [
"BULLET::::- US/America/North America: The terms 'America' and 'American' are frequently used to refer only to the United States and its people. This sometimes causes resentment among some non-US Americans, especially Latin Americans, who tend to respond by referring to the people of the US as Unitedstatesian (or 'estadounidenses' in Spanish), at least when not using the unofficial term 'gringos'. The practice is sometimes also followed by native English speakers who wish to show they are sympathetic to Latin Americans, and/or when translating texts into English. The practice can also be found in Mexico, even though Mexico is normally considered part of North America. A Canadian may sometimes be described as 'un norteamericano de Canada' (a North American of Canada). See also use of the word American.\n",
"Americans may be seen as arrogant people. They are frequently depicted in foreign media as obsessively nationalistic and obnoxiously patriotic, referring to the U.S. as \"the greatest country in the world\" and patronising people from other countries.\n",
"This quote is sometimes attributed to Dulles: \"The United States of America does not have friends; it has interests.\" The words were spoken by President Charles de Gaulle of France. This misquotation can be attributed to Dulles' visit to Mexico in 1958, during which anti-American protesters carried signs reading \"The U.S. has no friends, only interests.\"\n",
"\"People ask us all the time, 'Why did it have to be these words? Couldn't you just call it \"African American/Latin American/Chinese?\"' My answer to that is, why not these words? What is it that people are so afraid of? It's a shame that someone's day is ruined if they see a poster of ours. When people are offended it's because of their own experiences they've had with these words. We're not out to offend anyone, and we're not using these words against people. When the three of us got together, the title just came and it was perfect: These are the words we've been dealing with our whole lives.\"\n",
"\"I know these are difficult times. I know folks are worried. But I also know this - we can steer ourselves out of this crisis. Because we are the United States of America. We are the country that has faced down war and depression; great challenges and great threats. And at each and every moment, we have risen to meet these challenges - not as Democrats, not as Republicans, but as Americans. We still have the most talented, most productive workers of any country on Earth. We're still home to innovation and technology, colleges and universities that are the envy of the world. Some of the biggest ideas in history have come from our small businesses and our research facilities. It won't be easy, but there's no reason we can't make this century another American century.\" \n",
"While the stereotype of hard-working Americans is often a positive one, the United States has also been criticized in recent years as a workaholic culture. In \"The Huffington Post\", Tijana Milosevic, a Serbian who had traveled to Washington, D.C. for a degree, wrote, \"In fact my family and friends had observed that I shouldn’t have chosen America, since I would probably feel better in Western Europe — where life is not as fast paced as in the US and capitalism still has a 'human face.'\" She noted that \"Americans still work nine full weeks (350 hours) longer than West Europeans do and paid vacation days across Western Europe are well above the US threshold.\" Researchers at Oxford Economics hired by the US Travel Association estimated that in 2014 \"about 169m [vacation] days, equivalent to $52.4bn in lost benefits\", went unused by American workers. Professor Gary L. Cooper argued Americans \"have a great deal to learn from Europeans about getting better balance between work and life\" and wrote:\n",
"It's not as truly hostile about Americans as say \"Born in the U.S.A.\": it's merely sardonic. I was traveling in Java when [its] first McDonald's went up: it was like, \"for fuck's sake.\" The invasion by any homogenized culture is so depressing, the erection of another Disney World in, say, Umbria, Italy, more so. It strangles the indigenous culture and narrows expression of life.\n"
] |
What would happen to a single photon in a perfect vacuum? | A photon in a perfect vacuum will travel in a perfectly strait line until it hits something. If you put a photographic plate in the way, you would see one dot of light surrounded by darkness. | [
"BULLET::::- Perfect vacuum is an ideal state of no particles at all. It cannot be achieved in a laboratory, although there may be small volumes which, for a brief moment, happen to have no particles of matter in them. Even if all particles of matter were removed, there would still be photons and gravitons, as well as dark energy, virtual particles, and other aspects of the quantum vacuum.\n",
"Owing to the Dirac sea, an empty space which appears to be a pure vacuum is filled with virtual subatomic particles. These are called vacuum fluctuations. As a photon travels through a vacuum it interacts with these virtual particles and is absorbed by them to give rise to a virtual electron–positron pair. This pair is unstable and quickly annihilates to produce a photon like the one which was previously absorbed. The time the photon's energy spends as subluminal electron-positron pairs lowers the observed speed of light in a vacuum.\n",
"In a process in which a photon is annihilated (absorbed), we can think of the photon as making a transition into the vacuum state. Similarly, when a photon is created (emitted), it is occasionally useful to imagine that the photon has made a transition out of the vacuum state. An atom, for instance, can be considered to be \"dressed\" by emission and reabsorption of \"virtual photons\" from the vacuum. The vacuum state energy described by is infinite. We can make the replacement:\n",
"BULLET::::- Therefore, since there had to be an invisible \"something\" to move the light through the glass tube, there was no vacuum in the tube. Not in the glass tube or anywhere else. Vacuums – the absence of any and everything – were simply an impossibility.\n",
"The experimental determination has been made in vacuum. However, the vacuum we know is not the only possible vacuum which can exist. The vacuum has energy associated with it, called simply the vacuum energy, which could perhaps be altered in certain cases. When vacuum energy is lowered, light itself has been predicted to go faster than the standard value \"c\". This is known as the Scharnhorst effect. Such a vacuum can be produced by bringing two perfectly smooth metal plates together at near atomic diameter spacing. It is called a Casimir vacuum. Calculations imply that light will go faster in such a vacuum by a minuscule amount: a photon traveling between two plates that are 1 micrometer apart would increase the photon's speed by only about one part in 10. Accordingly, there has as yet been no experimental verification of the prediction. A recent analysis argued that the Scharnhorst effect cannot be used to send information backwards in time with a single set of plates since the plates' rest frame would define a \"preferred frame\" for FTL signalling. However, with multiple pairs of plates in motion relative to one another the authors noted that they had no arguments that could \"guarantee the total absence of causality violations\", and invoked Hawking's speculative chronology protection conjecture which suggests that feedback loops of virtual particles would create \"uncontrollable singularities in the renormalized quantum stress-energy\" on the boundary of any potential time machine, and thus would require a theory of quantum gravity to fully analyze. Other authors argue that Scharnhorst's original analysis, which seemed to show the possibility of faster-than-\"c\" signals, involved approximations which may be incorrect, so that it is not clear whether this effect could actually increase signal speed at all.\n",
"For the squeezed vacuum state the photon number distribution displays odd-even-oscillations. This can be explained by the mathematical form of the squeezing operator, that resembles the operator for two-photon generation and annihilation processes. Photons in a squeezed vacuum state are more likely to appear in pairs.\n",
"In nature, a light source emits a ray of light which travels, eventually, to a surface that interrupts its progress. One can think of this \"ray\" as a stream of photons traveling along the same path. In a perfect vacuum this ray will be a straight line (ignoring relativistic effects). Any combination of four things might happen with this light ray: absorption, reflection, refraction and fluorescence. A surface may absorb part of the light ray, resulting in a loss of intensity of the reflected and/or refracted light. It might also reflect all or part of the light ray, in one or more directions. If the surface has any transparent or translucent properties, it refracts a portion of the light beam into itself in a different direction while absorbing some (or all) of the spectrum (and possibly altering the color). Less commonly, a surface may absorb some portion of the light and fluorescently re-emit the light at a longer wavelength color in a random direction, though this is rare enough that it can be discounted from most rendering applications. Between absorption, reflection, refraction and fluorescence, all of the incoming light must be accounted for, and no more. A surface cannot, for instance, reflect 66% of an incoming light ray, and refract 50%, since the two would add up to be 116%. From here, the reflected and/or refracted rays may strike other surfaces, where their absorptive, refractive, reflective and fluorescent properties again affect the progress of the incoming rays. Some of these rays travel in such a way that they hit our eye, causing us to see the scene and so contribute to the final rendered image.\n"
] |
Can 3 objects orbit each other? | Yes, it's not super rare. The most common configuration is that two of them are much closer together than the third one, and they orbit each other while the third one orbits both of them (Alpha Centauri may be like this).
_URL_0_ | [
"Considering possible hovering positions or orbits of the tractor around the asteroid, note that if two objects are gravitationally bound in a mutual orbit, then if one receives an arbitrary impulse which is less than that needed to free it from orbit around the other, because of the gravitational forces between them, the impulse will alter the momentum of both, together regarded as a composite system.\n",
"In other words, images of an object and of its transformations correspond to a orbit formula_20. If two orbits have a point in common they are identical everywhere, i.e. an orbit is an invariant and unique representation of an image. So, two images are called equivalent when they belong to the same orbit: formula_25 if formula_26 such that formula_27. Conversely, two orbits are different if none of the images in one orbit coincide with any image in the other.\n",
"It can be said that two objects in space orbiting each other in the absence of other forces are in free fall around each other, e.g. that the Moon or an artificial satellite \"falls around\" the Earth, or a planet \"falls around\" the Sun. Assuming spherical objects means that the equation of motion is governed by Newton's Law of Universal Gravitation, with solutions to the gravitational two-body problem being elliptic orbits obeying Kepler's laws of planetary motion. This connection between falling objects close to the Earth and orbiting objects is best illustrated by the thought experiment, Newton's cannonball.\n",
"In astronomy, a co-orbital configuration is a configuration of two or more astronomical objects (such as asteroids, moons, or planets) orbiting at the same, or very similar, distance from their primary, i.e. they are in a 1:1 mean-motion resonance. (or 1:−1 if orbiting in opposite directions).\n",
"Co-located satellites cannot actually be positioned at the same point on the geostationary satellite arc. In fact, they are just close enough together to appear to be at the same position so far as the beamwidth of the receiving dish is concerned. SES maintains its co-located satellites within an imaginary 150 km cube in space, centred on the notional orbital position.\n",
"All the elements that can be superimposed on each other by symmetries are said to form a symmetry orbit. For example, all the faces of a cube lie in one orbit, while all the edges lie in another. If all the elements of a given dimension, say all the faces, lie in the same orbit, the figure is said to be transitive on that orbit. For example, a cube is face-transitive, while a truncated cube has two symmetry orbits of faces.\n",
"As two objects orbit each other, the periapsis is that point at which the two objects are closest to each other and the apoapsis is that point at which they are the farthest. (More specific terms are used for specific bodies. For example, \"perigee\" and \"apogee\" are the lowest and highest parts of an orbit around Earth, while \"perihelion\" and \"aphelion\" are the closest and farthest points of an orbit around the Sun.)\n"
] |
How does heat transfer within a solid differ from heat transfer between a solid and air (convection)? | In equilibrium, everything will reach the same temperature. If we assume that the room as a whole is a closed system, the answer is as easy as calculating the total heat capacity and the total heat.
Let's make the problem even easier: We have a small room of 10 m^3 in volume. In this room, we have an iron cube that weighs 1 kg. Air has a heat capacity of about 1 J/(g K) (according to [this website](_URL_0_)), iron has about half that, 0.45 J/(g K).
The air inside the room has a density of about 1.2 kg/m^3 (wikipedia), so we have about 12 kg air inside our room. The total heat capacity of the air is, therefore, 12 J/K and the heat capacity of the iron cube is 0.45 J/K.
So, if we dump some amount of energy into the room, about 27 times as much energy would go into the air than the iron. Or, in other words, to heat the air by 1 K, the block would have to be 27 K above room temperature.
If you're asking about the dynamics of the heat transfer, the answer will be a lot more complex. It depends on the material properties and shape. | [
"In conduction, the heat flow is within and through the body itself. In contrast, in heat transfer by thermal radiation, the transfer is often between bodies, which may be separated spatially. Also possible is transfer of heat by a combination of conduction and thermal radiation. In convection, internal energy is carried between bodies by a moving material carrier. In solids, conduction is mediated by the combination of vibrations and collisions of molecules, of propagation and collisions of phonons, and of diffusion and collisions of free electrons. In gases and liquids, conduction is due to the collisions and diffusion of molecules during their random motion. Photons in this context do not collide with one another, and so heat transport by electromagnetic radiation is conceptually distinct from heat conduction by microscopic diffusion and collisions of material particles and phonons. But the distinction is often not easily observed, unless the material is semi-transparent.\n",
"Convective heat transfer, or convection, is the transfer of heat from one place to another by the movement of fluids, a process that is essentially the transfer of heat via mass transfer. Bulk motion of fluid enhances heat transfer in many physical situations, such as (for example) between a solid surface and the fluid. Convection is usually the dominant form of heat transfer in liquids and gases. Although sometimes discussed as a third method of heat transfer, convection is usually used to describe the combined effects of heat conduction within the fluid (diffusion) and heat transference by bulk fluid flow streaming. The process of transport by fluid streaming is known as advection, but pure advection is a term that is generally associated only with mass transport in fluids, such as advection of pebbles in a river. In the case of heat transfer in fluids, where transport by advection in a fluid is always also accompanied by transport via heat diffusion (also known as heat conduction) the process of heat convection is understood to refer to the sum of heat transport by advection and diffusion/conduction.\n",
"On a microscopic scale, heat conduction occurs as hot, rapidly moving or vibrating atoms and molecules interact with neighboring atoms and molecules, transferring some of their energy (heat) to these neighboring particles. In other words, heat is transferred by conduction when adjacent atoms vibrate against one another, or as electrons move from one atom to another. Conduction is the most significant means of heat transfer within a solid or between solid objects in thermal contact. Fluids—especially gases—are less conductive. Thermal contact conductance is the study of heat conduction between solid bodies in contact. The process of heat transfer from one place to another place without the movement of particles is called conduction, such as when placing a hand on a cold glass of water - heat is conducted from the warm skin to the cold glass, but if the hand is held a few inches from the glass, little conduction would occur since air is a poor conductor of heat. Steady state conduction is an idealized model of conduction that happens when the temperature difference driving the conduction is constant, so that after a time, the spatial distribution of temperatures in the conducting object does not change any further (see Fourier's law). In steady state conduction, the amount of heat entering a section is equal to amount of heat coming out, since the change in temperature (a measure of heat energy) is zero. An example of steady state conduction is the heat flow through walls of a warm house on a cold night - inside the house is maintained at a high temperature, and outside the temperature stays low, so the transfer of heat per unit time stays near a constant rate determined by the insulation in the wall, and the spatial distribution of temperature in the walls will be approximately constant over time.\n",
"The convection heat transfer mode comprises one mechanism. In addition to energy transfer due to specific molecular motion (diffusion), energy is transferred by bulk, or macroscopic, motion of the fluid. This motion is associated with the fact that, at any instant, large numbers of molecules are moving collectively or as aggregates. Such motion, in the presence of a temperature gradient, contributes to heat transfer. Because the molecules in aggregate retain their random motion, the total heat transfer is then due to the superposition of energy transport by random motion of the molecules and by the bulk motion of the fluid. It is customary to use the term convection when referring to this cumulative transport and the term advection when referring to the transport due to bulk fluid motion.\n",
"Convective heat transfer, often referred to simply as convection, is the transfer of heat from one place to another by the movement of fluids. Convection is usually the dominant form of heat transfer in liquids and gases. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes of unknown conduction (heat diffusion) and advection (heat transfer by bulk fluid flow).\n",
"Convective heat transfer is one of the major types of heat transfer, and convection is also a major mode of mass transfer in fluids. Convective heat and mass transfer takes place both by diffusion – the random Brownian motion of individual particles in the fluid – and by advection, in which matter or heat is transported by the larger-scale motion of currents in the fluid. In the context of heat and mass transfer, the term \"convection\" is used to refer to the combined effects of advective and diffusive transfer. Sometimes the term \"convection\" is used to refer specifically to \"free heat convection\" (natural heat convection) where bulk-flow in a fluid is due to temperature-induced differences in buoyancy, as opposed to \"forced heat convection\" where forces other than buoyancy (such as pump or fan) move the fluid. However, in mechanics, the correct use of the word \"convection\" is the more general sense, and different types of convection should be further qualified, for clarity.\n",
"Convection cannot take place in most solids because neither bulk current flows nor significant diffusion of matter can take place. Diffusion of heat takes place in rigid solids, but that is called heat conduction. Convection, additionally may take place in soft solids or mixtures where solid particles can move past each other.\n"
] |
why are languages all so different... but body language is so similar everywhere? eye-rolls, shrugs, clapping, skeptical eyebrow raises etc.. | Body language is *not* similar everywhere. In fact, some gestures mean exactly the opposite of what you expect in other cultures. [Here's a page](_URL_0_) that talks about the topic.
And [another](_URL_1_) short page with some of the confusing gestures from around the world.
| [
"Languages, understood as the particular set of speech norms of a particular community, are also a part of the larger culture of the community that speaks them. Languages differ not only in pronunciation, vocabulary, and grammar, but also through having different \"cultures of speaking.\" Humans use language as a way of signalling identity with one cultural group as well as difference from others. Even among speakers of one language, several different ways of using the language exist, and each is used to signal affiliation with particular subgroups within a larger culture. Linguists and anthropologists, particularly sociolinguists, ethnolinguists, and linguistic anthropologists have specialized in studying how ways of speaking vary between speech communities.\n",
"When speakers of different languages interact closely, it is typical for their languages to influence each other. Through sustained language contact over long periods, linguistic traits diffuse between languages, and languages belonging to different families may converge to become more similar. In areas where many languages are in close contact, this may lead to the formation of language areas in which unrelated languages share a number of linguistic features. A number of such language areas have been documented, among them, the Balkan language area, the Mesoamerican language area, and the Ethiopian language area. Also, larger areas such as South Asia, Europe, and Southeast Asia have sometimes been considered language areas, because of widespread diffusion of specific areal features.\n",
"However, languages, now understood as the particular set of speech norms of a particular community, are also a part of the larger culture of the community that speak them. Humans use language as a way of signalling identity with one cultural group and difference from others. Even among speakers of one language several different ways of using the language exist, and each is used to signal affiliation with particular subgroups within a larger culture. In linguistics such different ways of using the same language are called \"varieties\". For example, the English language is spoken differently in the US, the UK and Australia, and even within English-speaking countries there are hundreds of dialects of English that each signals a belonging to a particular region and/or subculture. For example, in the UK the cockney dialect signals its speakers' belonging to the group of lower class workers of east London. Differences between varieties of the same language often consist in different pronunciations and vocabulary, but also sometimes of different grammatical systems and very often in using different styles (e.g. cockney rhyming slang or lawyers' jargon). Linguists and anthropologists, particularly sociolinguists, ethnolinguists and linguistic anthropologists have specialized in studying how ways of speaking vary between speech communities.\n",
"Recent research with non-linguistic experiments in languages with different grammatical properties (e.g., languages with and without numeral classifiers or with different gender grammar systems) showed that language differences in human categorization are due to such differences. Experimental research suggests that this linguistic influence on thought diminishes over time, as when speakers of one language are exposed to another.\n",
"Many languages have different pronouns, particularly in the second person, depending on the degree of formality or familiarity. It is common for different pronouns to be used when addressing friends, family, children and animals than when addressing superiors and adults with whom the speaker is less familiar. Examples of such languages include French, where the singular \"tu\" is used only for familiars, the plural \"vous\" being used as a singular in other cases (Russian follows a similar pattern); German, where the third-person plural \"sie\" (capitalized as \"Sie\") is used as both singular and plural in the second person in non-familiar uses; and Polish, where the noun \"pan\" (\"gentleman\") and its feminine and plural equivalents are used as polite second-person pronouns. For more details, see T–V distinction.\n",
"Connections between languages can be traced because the processes that change languages are not random, but follow strict patterns. Especially sound shifts, the changing of vowels and consonants, are important, although grammar (especially morphology) and the lexicon (vocabulary) may also be significant. Historical-comparative linguistics thus makes it possible to see great similarities between languages which at first sight might seem very different.\n",
"The connection between culture and language has been noted as far back as the classical period and probably long before. The ancient Greeks, for example, distinguished between civilized peoples and bárbaroi \"those who babble\", i.e. those who speak unintelligible languages. The fact that different groups speak different, unintelligible languages is often considered more tangible evidence for cultural differences than other less obvious cultural traits.\n"
] |
How do the antibodies in a blood donors blood behave in the blood recipients body? | They work just fine; this is basis of [immunoglobulin therapy](_URL_0_). However, they don't work very long; half-life of various immunoglobulins is only a few days.
What blocks the significant response from the recipient's immune system is that the recipient has to be immunosuppressed to receive a transplant (in which I include whole-blood transfusion).
Also worth noting: most cases in which you receive blood from someone, you don't get whole blood — you get only some parts of it (for example, red blood cells or plasma), and those parts don't include antibodies. It's only when you receive whole blood that you are getting everything, and that works pretty much like any transplant does. | [
"Blood donors with exceptionally strong anti-A, anti-B or any atypical blood group antibody may be excluded from blood donation. In general, while the plasma fraction of a blood transfusion may carry donor antibodies not found in the recipient, a significant reaction is unlikely because of dilution.\n",
"The donor's blood type must be determined if the blood will be used for transfusions. The collecting agency usually identifies whether the blood is type A, B, AB, or O and the donor's Rh (D) type and will screen for antibodies to less common antigens. More testing, including a crossmatch, is usually done before a transfusion. Type O negative is often cited as the \"universal donor\" but this only refers to red cell and whole blood transfusions. For plasma and platelet transfusions the system is reversed: AB positive is the universal platelet donor type while both AB positive and AB negative are universal plasma donor types.\n",
"BULLET::::- The blood type of the donor must match that of the recipient due to certain antigens that are present on donated lungs. A mismatch in blood type can lead to a strong response by the immune system and subsequent rejection of the transplanted organs. In an ideal case, as many of the human leukocyte antigens as possible would also match between the donor and the recipient, but the desire to find a highly compatible donor organ must be balanced against the patient's immediacy of need.\n",
"Receiving blood which contains an antigen which has never been in the patient's own blood causes an immune reaction due to the immune system of a hypothetical receiver producing immunoglobulins not only against antigen A and B, but also against H antigen. The most common immunoglobulins synthesized are IgM and IgG (and this seems to have a very important role in the low frequency of hemolytic disease of the newborn among non-Bombay offspring of Bombay mothers).\n",
"Additionally, red blood cell surface antigens other than A, B and Rh D, might cause adverse reactions and sensitization, if they can bind to the corresponding antibodies to generate an immune response. Transfusions are further complicated because platelets and white blood cells (WBCs) have their own systems of surface antigens, and sensitization to platelet or WBC antigens can occur as a result of transfusion.\n",
"BULLET::::- Antibodies: Donors are sometimes immunized against agents such as tetanus or hepatitis B so that their plasma contains the antibodies against the toxin or disease. In other donors, an intentionally incompatible unit of blood is transfused to produce antibodies to the antigens on the red cells. The collected plasma then contains these components, which are used in manufacturing of medications. Donors who are already ill may have their plasma collected for use as a positive control for laboratory testing.\n",
"The type of treatment depends on the severity of the patient’s bone marrow failure disease. Blood transfusion is one treatment. Blood is collected from volunteer donors who agree to let doctors draw blood stem cells from their blood or bone marrow for transplantation. Blood that is taken straight from collected blood stem cells is known as peripheral blood stem cell donation. A peripheral stem cell donor must have the same blood type as the patient receiving the blood cells. Once the stem cells are in the patient’s body through an IV, the cells mature and become blood cells. Before donation, a drug is injected into the donor, which increases the number of stem cells into their body. Feeling cold and lightheaded, having numbness around the mouth and cramping in the hands are common symptoms during the donation process. After the donation, the amount of time for recovery varies for every donor, “But most stem cell donors are able to return to their usual activities within a few days to a week after donation”.\n"
] |
why does a muscle become stiff when cold and limber when hot? | When cold, blood vessels contract so they are further from the skin's surface, losing less heat. This constriction means blood does not flow through the veins as much, limiting blood flow to muscles.
When hot, blood vessels expand so they are closer to the skin's surface to release heat. Wider vessels means more blood flow. | [
"Increased muscular activity results in the generation of heat as a byproduct. Most often, when the purpose of the muscle activity is to produce motion, the heat is wasted energy. In shivering, the heat is the main intended product and is utilized for warmth.\n",
"Ice can be used to decrease inflammation of sore or injured muscles. Heat can also aid in relieving sore muscles by improving blood circulation to them. While the whole arm generally feels painful in TOS, some relief can be seen when ice or heat is intermittently applied to the thoracic region (collar bone, armpit, or shoulder blades).\n",
"The overuse of the coracobrachialis can lead to stiffening of the muscle. Common causes of injury include chest workouts or activities that require one to press the arm very tight towards the body, e.g. work on the rings in gymnastics. Symptoms of overuse or injury are pain in the arm and shoulder, radiating down to the back of the hand. In more severe cases, the musculocutaneous nerve can get trapped, causing disturbances in sensation to the skin on the radial part of the forearm and weakened flexion of the elbow, as the nerve also supplies the biceps brachii and brachialis muscles. Actual rupture to the coracobrachialis muscle is extremely rare. Very few case reports exist in the literature, and it is reported to be caused by direct trauma to the contracted muscle. Avulsion of the muscle's origin from the coracoid as a result of indirect forces is even more unusual.\n",
"Contraction of the muscles has a number of different purposes. Its principal function in the majority of mammals is to provide insulation: air becomes trapped between the erect hairs, helping the animal retain heat. Erection of the porcupine's long, thick hairs causes the animal to become more intimidating, scaring predators. Pressure exerted by the muscle may cause sebum to be forced along the hair follicle towards the surface, protecting the hair.\n",
"BULLET::::- The hair on the skin lie flat, preventing heat from being trapped by the layer of still air between the hair. This is caused by tiny muscles under the surface of the skin called arrector pili muscles relaxing so that their attached hair follicles are not erect. These flat hairs increase the flow of air next to the skin increasing heat loss by convection. When environmental temperature is above core body temperature, sweating is the only physiological way for humans to lose heat.\n",
"Cold shortening is caused by the release of stored calcium ions from the sarcoplasmic reticulum of muscle fibers, in response to the cold stimulus. The calcium ions trigger powerful muscle contraction aided by ATP molecules. To prevent cold shortening, a process known as electrical stimulation is carried out, especially in beef carcasses, immediately after slaughter and skinning. In this process, the carcass is stimulated with alternating current, causing it to contract and relax, which depletes the ATP reserve from the carcass and prevents cold shortening.\n",
"The cremasteric muscle is part of the spermatic cord. When this muscle contracts, the cord is shortened and the testicle is moved closer up toward the body, which provides slightly more warmth to maintain optimal testicular temperature. When cooling is required, the cremasteric muscle relaxes and the testicle is lowered away from the warm body and is able to cool. Contraction also occurs in response to stress (the testicles rise up toward the body in an effort to protect them in a fight). There are persistent reports that relaxation indicates approach of orgasm. There is a noticeable tendency to also retract during orgasm.\n"
] |
How do extended-reach oil wells change direction underground? | Not my field of specialty but since no one has chimed in yet I'll give it a go:
[Directional Drilling](_URL_1_) can be done by controlling the orientation of the drill-bit at the bottom of the hole. I think usually it is accomplished by [hydraulic actuators](_URL_0_) located on the sides of the drill bit. These actuators push against the walls of the hole and thus can control where the tip of the drill points. Of course you have to have some sensors so you can determine the current orientation of the bit. It also requires the walls of the hole to be strong enough to support the stress of the actuators so the rig-workers add casing and liners to strengthen the well. | [
"The earliest oil wells in modern times were drilled percussively, by repeatedly raising and dropping a cable tool into the earth. In the 20th century, cable tools were largely replaced with rotary drilling, which could drill boreholes to much greater depths and in less time. The record-depth Kola Borehole used non-rotary mud motor drilling to achieve a depth of over .\n",
"Until the 1970s, most oil wells were vertical, although lithological and mechanical imperfections cause most wells to deviate at least slightly from true vertical. However, modern directional drilling technologies allow for strongly deviated wells which can, given sufficient depth and with the proper tools, actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal or nearly horizontal; a horizontal wellbore placed in a production zone has more surface area in the production zone than a vertical well, resulting in a higher production rate. The use of deviated and horizontal drilling has also made it possible to reach reservoirs several kilometers or miles away from the drilling location (extended reach drilling), allowing for the production of hydrocarbons located below locations that are either difficult to place a drilling rig on, environmentally sensitive, or populated.\n",
"Many modern oil and gas wells are drilled directionally. At first, loggers had to run their tools somehow attached to the drill pipe if the well was not vertical. Modern techniques now permit continuous information at the surface. This is known as logging while drilling (LWD) or measurement-while-drilling (MWD). MWD logs use mud pulse technology to transmit data from the tools on the bottom of the drillstring to the processors at the surface.\n",
"Wells are drilled into oil reservoirs to extract the crude oil. \"Natural lift\" production methods that rely on the natural reservoir pressure to force the oil to the surface are usually sufficient for a while after reservoirs are first tapped. In some reservoirs, such as in the Middle East, the natural pressure is sufficient over a long time. The natural pressure in most reservoirs, however, eventually dissipates. Then the oil must be extracted using \"artificial lift\" means. Over time, these \"primary\" methods become less effective and \"secondary\" production methods may be used. A common secondary method is \"waterflood\" or injection of water into the reservoir to increase pressure and force the oil to the drilled shaft or \"wellbore.\" Eventually \"tertiary\" or \"enhanced\" oil recovery methods may be used to increase the oil's flow characteristics by injecting steam, carbon dioxide and other gases or chemicals into the reservoir. In the United States, primary production methods account for less than 40 percent of the oil produced on a daily basis, secondary methods account for about half, and tertiary recovery the remaining 10 percent. Extracting oil (or \"bitumen\") from oil/tar sand and oil shale deposits requires mining the sand or shale and heating it in a vessel or retort, or using \"in-situ\" methods of injecting heated liquids into the deposit and then pumping the liquid back out saturated with oil.\n",
"The earliest wells were water wells, shallow pits dug by hand in regions where the water table approached the surface, usually with masonry or wooden walls lining the interior to prevent collapse. Modern drilling techniques utilize long drill shafts, producing holes much narrower and deeper than could be produced by digging.\n",
"In areas with a high concentration of oil wells, it is not unusual for wells to communicate through the formation for distances of up to mile. During a fracing operation thousands of gallons of fluid and sand are pumped down one well to open up the formation surrounding that wellbore. Often large amounts of that proppant and fluid will travel through the formation and into a nearby well. This sand can lodge on top of a packer or coil tubing in the well sticking the pipe. \n",
"Historically in the United States, in some oil fields the oil rose naturally to the surface, but most of these fields have long since been used up, except in parts of Alaska. Often many wells (called \"multilateral wells\") are drilled into the same reservoir, to an economically viable extraction rate. Some wells (\"secondary wells\") may pump water, steam, acids or various gas mixtures into the reservoir to raise or maintain the reservoir pressure and economical extraction rate.\n"
] |
how do radio signals (4g, wifi etc.) manage to retain their information after passing through trees, buildings and other obstacles? and how are they not mixed up, intertwined? | They are, the key is there are error correction and detection algorithms that work to counter the problem. In bad environments they don't always work.
Also, many newer devices actually utilize the attenuation and reflections to improve signal quality. Take a look into [MIMO](_URL_0_) technology. They do what is called [beamforming](_URL_1_) where they vary the signal being output on multiple antennae to create hot spots in the signal at the receiving antenna(e) to improve reception. When multiple devices are connected it will actually change the beam forming per device moment to moment depending on the destination. It's really cool stuff.
Edits: Links, typos.
Edit 2: Figured I could expand as well. When you're dealing with reflections or other signals that could potentially interfere, they are usually a bit weaker than the main signal. This means that a receiver can filter them out by simply ignoring signals that are weaker than a certain level. This is called the noise floor of the radio. Think of it like being in a room full of people talking and ignoring all the background conversations because they're harder to hear and focusing on your current one.
Attenuation of the main signal works similarly. As long as the signal isn't attenuated below the noise floor, it will work. If the operating environment for the radios is bad enough, it may be impossible to get a strong enough signal to overcome the noise floor, and then nothing works. | [
"BULLET::::- Cognitive radio techniques: each radio measures the spectrum in use and communicates that information to other cooperating radios, so that transmitters can avoid mutual interference by selecting unused frequencies. Alternatively, each radio connects to a geolocation database to obtain information about the spectrum occupancy in its location and, flexibly, adjusts its operating frequency and/or transmit power not to cause interference to other wireless services.\n",
"For example, in TV and radio broadcasting, information flows only from the transmitter site to multiple receivers. A pair of walkie-talkie two-way radios provide a simplex circuit in the ITU sense; only one party at a time can talk, while the other listens until it can hear an opportunity to transmit. The transmission medium (the radio signal over the air) can carry information in only one direction. \n",
"Wireless units will be installed in vehicles and probably also in fixed locations such as near traffic signals and emergency call boxes along the road. Sensors in the cars and at the fixed locations, as well as possible connections to wider networks, will provide the information, which will be displayed to the drivers in some way. The range of the radio links can be extended by forwarding messages along multi-hop paths. Even without fixed units, information about fixed hazards can be maintained by moving vehicles by passing it backwards. It also seems possible for traffic lights, which one can expect to become smarter, to use this information to reduce the chance of collisions.\n",
"Radio signals have a limitations due to distance and terrain. If two radios are far apart, or there is a mountain in the way, they will not be able to communicate. To alleviate this, radio repeaters are installed on mountaintops to repeat the signal from one radio to another, or group of others. This is a standard repeater site. The signal is received by the repeater from the originating radio and re-broadcast so the receiving radio(s) can receive the radio signal. A repeater site gives approximately a 50-mile radius of coverage. \n",
"Depending upon the Engineering set up, radiotelegraph stations may use either a single antenna for both transmit and receive or, separate transmit and receive antennas. In either case, when receivers are operating on the same or nearby radio frequencies as used by their associated transmitters, while using the same or nearby antennas, the typical radio receiver is thus exposed to extremely large signals from the nearby transmitter. This situation would generally result in the destruction or degradation of the receiver front end circuitry and would be problematic at best and destructive at worst. As of this writing there has yet apparently been no receiver technology developed that can operate with full sensitivity over such a huge range of received signal levels whilst also safely withstanding the high power levels presented by the associated nearby transmitter. And so receiver inputs cannot simply be bridged across transmitting antenna terminals! Receivers must be isolated from the powerful transmitter signals by some means. These means are provided by the so-called T/R switches.\n",
"Many types of radio transmissions depend, to varying degrees, on line of sight (LOS) between the transmitter and receiver. Obstacles that commonly cause NLOS conditions include buildings, trees, hills, mountains, and, in some cases, high voltage electric power lines. Some of these obstructions reflect certain radio frequencies, while some simply absorb or garble the signals; but, in either case, they limit the use of many types of radio transmissions, especially when low on power budget.\n",
"First, from the routing information, the sending radio constructs a list of radios that might be able to forward data from the sending radio to the destination. The radios' numbers are placed in a list sorted by distance to the destination, from closest to furthest. The destination radio is at the head of the list. Also, the source radio starts a list of the packets in the batch in order to measure packets' progress. This \"batch map\" is an array of radio numbers, one per packet. Each radio number is the radio that transmitted that packet, and was closest to the destination radio. Each data packet has the list of radios, and packets placed in the front. The list saves space in each packet by using radio numbers rather than IP addresses. Then, the sending radio broadcasts the first batch of data packets. It starts a timer. Radios that receive a packet but are not in the list in the packet ignore the data packets. These radios throw away the packets as soon as the packets are received. Radios that are in the packet's list of radios save the data packets that they receive. They also update their batch map. When a radio times out, it transmits the packets that no radio closer to the destination has retransmitted. These packets include the radio's best available information about the progress of the packets in the batch (i.e. its batch map). In particular, each packet's batch map contains the retransmitter's radio number for each packet that it retransmits. When a radio receives a packet sent from a radio that is closer to the destination, it erases its own copy of that packet. There's no need for it to retransmit that packet. However, it also updates its batch map about the progress of the packets in the batch. In this way, the information about the progress of the packets flows backward toward the source as radios farther from the destination update their batch maps by eavesdropping on retransmissions.\n"
] |
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