question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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why do objects kept in the pockets of trousers often make a white-ish outline in the material? | The hard object in your pocket creates raised areas in the fabric, and they do not give way when you brush up against an object. When you move around, you are constantly brushing up next to stationary objects, and your pants being soft, just move out of the way. But the hard items in your pockets can't move, causing the fabric above them to be pressed hard against the stationary object. Since the corners of those objects are the most prominent features, they will have the greatest amount of contact.
The result is that material from the stationary object can be transferred to your pants in those locations. Material like dust, chalky particles, and lint can all be wiped away fairly easily. However, over an extended time wearing those pants with the same objects in the same pockets, you will find that the fabric will begin to wear thin, and the dye in the fabric will fade. This can result in permanent lines, and holes may develop at sharp corners.
My older pairs of pants have visible outlines for my phone and wallet, especially those ones I wore while working. | [
"In the simplest design, a square of fabric is cut with an opening in the middle for the waistband. When the skirt is put on, the four corners hang down as points. More panels of material can be used to increase the number of corners, or points, along the hem.\n",
"The old type, also known as the , is a one-piece... |
why should i switch from rgb to cmyk? | Computer screens use [red, green, and blue lights](_URL_1_) in varying combinations/intensities to display colors, whereas printers use cyan, magenta, yellow, and black ("K"). By creating something in CMYK mode, you ensure your colors are more accurately represented when printed. If you never print anything, RGB mode is all you need.
I don't know much about Pantone, aside from the fact that they make [these nifty things](_URL_0_)... | [
"There are no simple formulas for conversion between RGB or CMYK values and \"L*a*b*\", because the RGB and CMYK color models are device-dependent. The RGB or CMYK values first must be transformed to a specific absolute color space, such as sRGB or Adobe RGB. This adjustment will be device-dependent, but the result... |
how do ticket-less rallies like the women's march calculate attendance? | Although the task of determining how many people attend something as large as say, a political rally or a protest may seem like a daunting, almost impossible undertaking to do with any accuracy, with some basic information, it's actually not that difficult to get reasonably accurate results.
The most well-known method of estimating the size of a given crowd is simply called "The Jacobs' Method" as an ode to its inventor, Herbert Jacobs. Jacobs spent a few decades working for the Milwaukee Journal before retiring into teaching journalism at the University of California, Berkeley in the 1960s. He thought up his very simple crowd size estimate method after observing numerous Vietnam War protests outside of his office window.
Jacobs noticed that the area the students stood on had a repeating grid-like pattern, meaning he could very easily count how many students occupied a certain amount of space by counting how many students on average seemed to be able to stand inside a section of the grid. By doing this, he soon noticed some patterns.
For example, Jacobs found that in the most densely packed crowds, each person took up approximately 2.5 square feet. We should note that this is the absolute upper limit of a how dense a crowd can safely get, as in, you simply couldn't fit more people into a crowd this dense without someone being trampled or worse, which is probably why most, including some scholarly articles on the subject we read, simply refer to it as "mosh-pit density". In a dense, but more manageable crowd, Jacobs observed that participants had a comparably more roomy 4.5 square feet whilst those in a "light" crowd had a positively breezy 10 square feet to themselves.
In any event, once he had the approximate average number of students in each grid, he could then easily calculate the number of grids in an area occupied at a given density, and quite quickly come up with a very good estimate of how many people were in a given crowd. Thus, the now Gold Standard, and remarkably simple, "Jacobs' Method" was born.
This may sound like an overly simple solution but the truth is, it's strikingly accurate when done by non-biased observers, and modern technology has only made it easier. For instance, tools like Google Earth have made learning the exact size and area of a location, as well as dividing an area into grids, an almost trivial feat for just about anyone. And thanks to ubiquitous media coverage, any large gathering of people is going to have video or photographic footage (if not just scanning the Tweetosphere for people in the crowd who may have gotten a good shot and posted it online). So breaking things down from there is relatively trivial. Of course, one could get really fancy and take a photo of an entire crowd and use a bit of custom designed image processing software to programmatically count the people in a crowd for a more exact number, but the extra level of accuracy here over the properly executed Jacobs' Method isn't really typically that much, nor all that necessary.
Of course, when giving estimations, sometimes the news media or the organisers of an event do like to fudge the numbers a bit. Perhaps the most famous example is that of the Million Man March- a mass gathering of African Americans (mostly men) that took place in 1995. As you can probably guess from the name of the march, event organisers afterwards were very insistent that at least a million men had attended, with estimates going as high as two million. However, the National Parks Service disagreed and offered up a much lower, but still extremely significant figure of around 400,000 individuals. But when something is called the Million Man March, 400,000 seems a bit of a letdown, even though it's logically very much not; getting 400,000 people (about 1.2% of all African Americans in the United States at the time) to show up at such an event in Washington DC is really quite a feat.
Nevertheless, the NPS's estimate incensed a key player behind the march, Louis Farrakhan, so much so that he threatened to sue the NPS. As a direct result of the brouhaha that followed, the NPS is now banned by congress from estimating the size of crowds in Washington, at least publicly. As they noted, if the President asks them for how big a crowd was, they're happy to crunch the numbers given footage of the crowd. They just aren't technically supposed to use tax payer dollars in this way anymore, so wouldn't share that information with the media who, of course, could quite easily come up with their own estimates.
So how many people actually attended the Million Man March? While an exact figure is impossible to discern, most researchers are in agreement that the original estimation of the NPS is pretty accurate. For example, in 2004 a pair of researchers, Clark McPhail and John D. McCarthy, worked out that in the location of the gathering there would have been space for a maximum of 1,048,206 people assuming that every inch of the crowd was as densely packed as safely possible at 2.5 square feet per person. In the end, from the pictures available of the gathering, they determined that the NPS's estimate of about 400,000 was quite accurate. | [
"March on The Polls is March On's election-year initiative to increase voter turnout and change the narrative around voting and civic participation. Women's March and other grassroots groups in cities across the country are planning events aimed at increasing progressive turnout. These event range from marches, org... |
Can you recommend a book on the history of western fashion (approximately 20th century)? | I could have sworn that I put in a fashion section, but maybe I just suggested someone else paste my own list in. Anyway, I do have a [booklist in my profile](_URL_0_), though it does not have much in the way of description.
Here is the problem, though - "scholarly and in-depth" generally don't go along with something as broad as an overview. If you want to read an overview of any period of time in fashion, in the sense of "when and how styles changed", you ideally want Phyllis Tortora and Keith Eubank's *Survey of Historic Costume*, which is the textbook in use by most, if not all, fashion history courses. For a more scholarly work, I'd need to know what topic you're looking for within that timeframe. | [
"The history of Western fashion is the story of the changing fashions in clothing for men and women in Europe and other countries under influence of the Western world, from the 12th century to the present.\n",
"The Western Heritage is an American history textbook used for the study of Western civilization and Eur... |
Gaius Marius and the Roman Republic | I'll refer to "The Making of a Roman Army" by Lawrence Keppie on this :
"Of all the reforms attributed to Marius, the opening of the ranks to the capite censi (the head count; the slice of Roman society without much property) has
attracted most attention, and the unanimous disapproval of ancient writers. It has been
held by many in modern times, following the denunciations or asides of hostile ancient
authorities, that Marius’ action paved the way for the lawless, greedy soldiery whose
activities were thought to have contributed largely to the disgrace and fall of the Republic
a few generations later.
**However, it can be pointed out at once that Marius was not the first to enrol the capite
censi; at times of extreme crisis in the past the Senate had impressed them for service, for
example, after Cannae.** Moreover, and more important, **Marius was merely carrying one
stage further a process visible throughout the second century, by which the prescribed
property qualification for service was eroded and became less meaningful.** The Servian
Constitution, as reported by Livy, had ordained a minimum property qualification of
11,000 asses for service in the legions; scholars have judged that this bar was in force at
the time of the Second Punic War. However, Polybius reports that the qualification for
service was 400 Greek drachmae ( = 4000 asses); we have seen that he wrote about 160.
Finally Cicero, in a treatise whose dramatic date is 129, sets the minimum at 1500 asses.3
This last reduction could be ascribed to Gaius Gracchus in 123–122, whom we know to
have legislated that the state should be responsible for equipping the soldier fighting in its
defence. These successive reductions in the property minimum reflect a falling away in
the number of small or middling proprietors who traditionally provided the bulk of the
legions’ manpower. Already it would seem that by the time of Gaius Gracchus the
qualification had dropped below the level at which the soldier could afford to provide all
his own gear. A further reduction below the figure of 1500 asses (or the complete
abolition of the property qualification) could have been expected within the next
generation.
**Noticeably the sources do not say that Marius swept away the qualification (a
frequent assertion by modern scholars), or changed the law on eligibility, but merely that
he appealed to the capite censi for volunteers, whom he could equip from state funds
under the Gracchan legislation.** It could be argued therefore that there continued to be in
law a property-limit below which the citizen could not be forcibly conscripted. On the
other hand, nothing more is heard after Marius of any restrictions on the liability for
service, and it must be likely that the financial qualification was quietly dropped, either in
107, or in the run-up to the northern war of 102–101
**It must be stressed above all that Marius’ activities did not lead to any thorough
overhaul or reform of the conditions of military service**. As far as we can establish, the
six-year norm, and the 16-year maximum, continued to operate. The compulsory
enlistment of citizens continued during the first century BC, down to the time of Caesar
and beyond. Yet it is probably true to say that the balance shifted further towards the
near-professional army. Marius himself may well have seen the enrolment of the capite
censi in 107 as a one-off action, to obtain at short notice the reinforcements which he
could see were vital towards a speedy conclusion of the Jugurthine War. Certainly from
Marius’ time onwards we begin to find the aims and loyalties of the army and the state,
hitherto largely the same, yawning apart, with the soldiery starting to identify with the
fortunes of their commander, and giving higher priority to their personal advancement
and eventual enrichment. But the process was gradual, and it is not at all clear that
unbiased Roman observers of the first century would necessarily have regarded Marius
and the events of 107 as particularly significant in the long-term.
One particular consequence of the Marian ‘reform’ of army service has been seen in
the consequent offers of land which we find made to the soldiers as a reward for military
service in the first century. It is true that veterans of Marius’ African campaign were
given land there in 103 (some may indeed have never returned, or intended to return, to
Italy), and measures for the settlement of veterans of the northern wars were being
canvassed, and probably brought to fruition, in 100. Presumably the land went to those
who by their service with Marius now completed the legal minimum of service, rather
than to all-comers. **However, there is no indication (and indeed evidence to the contrary)
that land or a cash gratuity became a regular feature of military service in the following
century. The Senate was openly hostile to such rewards, whenever suggested, and most
generals felt disinclined to press for special treatment.** It was only under the stress of civil
war conditions that land plots and cash gratuities were regularly offered,
and obtained. " | [
"In order to survive in the complex and ever-shifting world of Roman politics, Gaius casts his lot in with his uncle Marius, who agrees to take both Gaius and Marcus under his wing. Marius is a Consul and one of the two most powerful men in Rome, the other being his great rival Sulla. After Marius secures a Triumph... |
why does a weird wavy patter appear if a small chequered pattern moves across a screen? | As always, there's [a relevant xkcd](_URL_0_) for that!
What you're seeing is a [moiré pattern](_URL_1_), which happens when a repeating pattern (lines, dots, a grid, etc) is more fine than the sensor/resolution of whatever is photographing or displaying it. Think of aliasing in videogames, where an angled line has to be represented with square pixels and can end up looking blocky and "jaggy" as a result. Moiré patterns are similar in that the camera or screen just can't capture every detail of the pattern and so some of the pixels end up shifting around to try to approximate it as best it can. | [
"Certain patterns, particularly those involving fine dots, can interact with the inversion and reveal visible cross-talk. If you try moving a small Window in front of the inversion pattern (above) which makes your screen flicker the most, you may well see cross-talk in the surrounding pattern.\n",
"Moiré patterns... |
how does thermal imaging work? | Heat sources emit electromagnetic radiation with a frequency respecting to their temperature. The visible spectrum of EM radiation ranges from red to violet. The sun's surface is about 5000 Kelvin hot and our eyes happen to see this light. Infrared means that the frequency of the EM radiation coming from an object is below the visible specrum due to lower temperature than the sun, anyway it can still be detected and it's frequency measured pretty accurately.
But How do we get a picture we CAN see?
Like digital cameras have light sensitive chips that render visible light directly to true red- green- and blue information in their memory, we can build a chip that detects light of lower frequency and renders it to any other colour and intensity value in real time.
It's just a microchip doing real time calculus, mapping the gathered frequency and intensity information to another color map we can display and see. | [
"Thermal images, or thermograms, are actually visual displays of the amount of infrared energy emitted, transmitted, and reflected by an object. Because there are multiple sources of the infrared energy, it is difficult to get an accurate temperature of an object using this method. A thermal imaging camera is capab... |
We know that there's a superior speed limit in the universe, the speed of light. Is there an inferior speed limit? | Motion is relative. You can always construct a perfectly consistent picture of the Universe (called a reference frame) in which you're at rest, or a particular given atom is at rest, and so on. In other words, complete rest is whatever you define it to be; there's no way to distinguish motion with a constant velocity from pure rest.
BQ1: Remember that matter is stuff, and energy is a quantity that any bit of stuff has. Energy isn't, as sci-fi movies and new age self-help books like to claim, some form of stuff as well. It's a *property* of matter. Can you have matter with zero energy? Not really. You have energy by moving, as well as an innate "rest energy" even when you're not moving (that's mc^(2)).
BQ2: The expansion is accelerating.
BQ3: If the Universe were decelerating (and until 1998 we thought it was, since gravity should pull everything together), then a big crunch collapse would be a possibility. But it wouldn't *have* to happen. The Universe could also decelerate, but at a slower and slower rate, so that the expansion rate slows down and slows down but never quite hits zero and turns around to contraction. This is a lot like launching a rocket at escape velocity (and turning the boosters off). It would always slow down due to the Earth's gravitational pull, but it would never slow down so much that it turned around and fell back down; it would just asymptotically approach zero speed. | [
"In special relativity, there is an unreachable speed, the speed of light. We can add speeds without end, but they will always be less than the speed of light. The sums of all speeds are limited by the speed of light. Additionally, the composition of two velocities is inferior to the sum of those two speeds.\n",
... |
In the history of mankind, is it likely that two people have had the same fingerprints? | There have been people who have shared 15+ minutiae on a single finger. Unfortunately we didn't find this out until following a terrorist attack in Spain, where an Algerian? man bombed a rail station?, and fingerprints found on a detonator matched an American lawyer. However, there are 100s of minutiae on each fingerprint, ten fingers, and exponential ways that fingerprints can be arranged. Hypothetically, it is possible, but highly, highly unlikely thus far in history. | [
"Although ancient peoples probably did not realize that fingerprints could uniquely identify individuals, references from the age of the Babylonian king Hammurabi (reigned 1792–1750 BCE) indicate that law officials would take the fingerprints of people who had been arrested. During China's Qin Dynasty, records have... |
If you throw the water out of a glass, in space, would the water move or remain in the glass? | If your throw was very weak, surface tension may be strong enough to keep the water in the glass, but a reasonable amount of acceleration would probably be enough to overcome surface tension and allow the water to freely flow from the glass. You would probably cause one or a few large globs of water to come out of the glass and start floating around. Surface tension is very strong and would ensure that the water does not fragment into many small droplets (which are less favorable than one large droplet because they require a higher surface area). There are [many good youtube videos](_URL_0_) showing how water behaves in space. | [
"Water itself is not a hazard to stable glass, but in the case of a piece with existing “glass disease,” it can accelerate problems associated with it such as weeping, and crizzling as mentioned above. Here, glass should not be kept in places where the threat of water exposure could occur, such as low to the ground... |
how many people lived in the city of Carthage in 150BC(IE right before the last punic war)? | Followup question how many people were there in Rome at this time? | [
"Carthage was one of the largest cities of the Hellenistic period and was among the largest cities in preindustrial history. Whereas by AD 14, Rome had at least 750,000 inhabitants and in the following century may have reached 1 million, the cities of Alexandria and Antioch numbered only a few hundred thousand or l... |
why are burmese buddhists so violent? | They’re so violent because they’re human.
In Myanmar/Burma, the Buddhists are the entrenched conservatives. The Rohinga are the foreign interlopers to them that won’t let things be done the good and proper way. When social pressure and non-violent pressure didn’t get them to conform, those in power turned to violence.
The fact that they claim to be Buddhist is beside the fact.
The same type of people have caused violence to visible minority ideology groups that threaten their power base under the guise of pretty much every ideology out there. | [
"Myanmar or Burma has been long torn by war and religious sectarianisms in the country. It is common to see violence of religious groups in the country, though varied between ethnics and rankings. Burmese Muslims, thus, are not out of range of violence despite of their indigenous Sufi faith.\n",
"Myanmar's govern... |
Why doesn't a course of antibiotics for a urinary tract infection kill off all the good bacteria in my digestive system? | There are several reasons. Firstly, different antibiotics target different bacterial systems (eg protein synthesis, cell wall formation etc) and differences in these systems between bacteria make some bacteria susceptible to treatment and some not. These bacteria would survive, continue to divide and perhaps develop and pass on (through horizontal mechanisms) resistance to other bacterial species in the flora. Finally, and I think this is quite cool (excitement aaaah), it is thought that bacteria can seek refuge in particular regions such as the appendix and survive this way. | [
"Altering the numbers of gut bacteria, for example by taking broad-spectrum antibiotics, may affect the host's health and ability to digest food. Antibiotics can cause antibiotic-associated diarrhea (AAD) by irritating the bowel directly, changing the levels of gut flora, or allowing pathogenic bacteria to grow. An... |
Anyone out there an expert in opiate pharmacology and physiology? | I am. And I think I can answer your question, the other two guys have skimmed over one vital aspect of opioid pharmacology(not trying to be a jerk or anything, I'm guessing this came off as though I'm a dick), and there is a very good reason as to why methadone specifically seems to cause this more than other opiates. Some opiates can, and will bind to other kinds of opioid receptors other than just the mu receptor. The main reason you become hungry for foods that provide a reward(taste really sweet, stuff you enjoy anyway, just maybe not to the same degree) DOES have to do with the mu receptor in that you're getting more reward out of something already rewarding(being on an opiate, be it for pain or recreation you are going to feel rewarded using the drug) but the biggest reason has to do with kappa-type 3 opioid receptor(also known as the nociceptin receptor) which actually increases appetite. Methadone binds to MU, Delta, and Kappa opioid receptors as well as having, if very mild, some NDMA antagonistic properties.
Also, some people on medications for chronic pain notice they gain weight more rapidly than before, and there is a reason for that too--they are chronic pain patients, they're using the drugs to treat pain, naturally they don't exercise that often or that well(which can be one of the root causes of their pain, specifically lower back pain).
With regards to medications you could take to prevent this from happening, well only things that inhibit your appetite would really be effective e.g. ritalin. However, they aren't made for this indication and its really not a very good idea really, it would work, most likely that is, but I wouldn't really be willing to prescribe a stimulant this way(I'm not the kind of doctor who treats ADD/ADHD either).
keep in mind this isn't medical advice.
| [
"Dr. Brigitte Kieffer (born February 26, 1958) is a French molecular neurobiologist known for her research of opiate receptors. Her areas of expertise include: molecular psychiatry, addiction, mood disorders, pain, and developmental disorders. Dr. Kieffer has international reputation in the field of opiate receptor... |
when a large company is broken up via anti-trust litigation, how is it decided who owns the new, smaller companies? | The same people who owned the larger company get an equal percentage of each of the smaller companies. | [
"Solutions to the diseconomies of scale for large firms may involve splitting the company into smaller organisations. This can either happen by default when the company is in financial difficulties, sells off its profitable divisions and shuts down the rest; or can happen proactively, if the management is willing.\... |
if the countries debt is so massive ($17.075 trillion?) why don't the gov't just go all out and spend even more? the amount of debt doesn't seem to matter | It doesn't seem to matter but it does. Technically the U.S. has a great credit score when it comes to paying off its loans. Our total debt is massive, but in the past the US has always paid off what it owes. If the US were to spend without check, it is more and more probable that they would in fact NOT be able to pay back the debt.
Every year when you hear about the debt ceiling, this is the government deciding whether to raise the amount that the US is allowed to be in debt, or to default on our loans. (Meaning we say we can't pay them off). If the US were to default, baaaad things would happen, and the results would be pretty catastrophic. Will the US actually be ever able to pay off its debt? Debatable. Someone with more economics knowledge than me can probably explain better but thats the main idea | [
"A significant number of economists and analysts dismiss any and all concerns over foreign holdings of United States government debt denominated in U.S. Dollars, including China's holdings. Critics of the \"excessive\" amount of US debt held by China acknowledge that the \"biggest effect of a broad-scale dump of US... |
Can someone with a neuro-biology background tell me if this research is bunk or not? | The Carhart-Harris research paper looks perfectly legit.
The interspersed commentary by Stuart Hameroff (great Scott! is he still at it?) is pure speculative fantasy. | [
"The neurobiologists apply a \"bottom-up\" research strategy in their studies. This strategy seems to prove necessary and sufficient to understand a brain in its entirety after the impressive achievements in studying the entire nervous system of a simple model organism, such as \"Caenorhabditis elegans\". However i... |
if we managed to somehow go beyond the edge of the expanding universe in a space ship, what would we find? | it doesn't have edges; relativistic cosmology describes a universe that curves in on itself, it's just like asking what would happen if you drove your car far enough to go beyond the horizon. The best way to picture the "expansion" is like a balloon being blown up; draw two points on the surface of the balloon and they keep getting further apart. | [
"The size of the Universe is somewhat difficult to define. According to the general theory of relativity, far regions of space may never interact with ours even in the lifetime of the Universe due to the finite speed of light and the ongoing expansion of space. For example, radio messages sent from Earth may never ... |
Does the heat produced by combustion engines have an effect on Earth's temperature? | Just made a quick calculation. [The world's yearly energy consumption is 104,426 TWh](_URL_0_). That's 375\*10^18 J.
Just 60 minutes of sunlight on Earth deliver 624*10^18 J (oversimplified Earth as a flat disc of 6371 km radius facing the Sun perpendicularly, solar power is 1360 W/m^(2)).
So, really, even if heat from engines does warm the environment up it's not by any significant amount. The real issue is trapping energy from sunlight and that happens because of greenhouse gases.
| [
"Assuming perfect combustion conditions, such as complete combustion under adiabatic conditions (i.e., no heat loss or gain), the adiabatic combustion temperature can be determined. The formula that yields this temperature is based on the first law of thermodynamics and takes note of the fact that the heat of combu... |
How do up and down quark decays produce W bosons? | The *W* bosons created in this process are examples of *virtual particles*. They are able to exist for a brief period of time, despite what you would expect from energy/momentum/mass properties of the physical particles, thanks to the uncertainty principle, but for the same reason, they cannot emerge as part of a final, physical state.
A short reddit post won't do the ideas justice. Let me instead point you to [Gordon Kane's piece](_URL_1_) in *Scientific American*.
If you want something more elaborate, check out [what John Baez](_URL_0_) wrote on the topic. | [
"In the so-called beta decay of a neutron (see picture, above), a down quark within the neutron emits a virtual boson and is thereby converted into an up quark, converting the neutron into a proton. Because of the energy involved in the process (i.e., the mass difference between the down quark and the up quark), th... |
There is a bird inside a large cargo plane. Does the plane weigh less if the bird flies inside the plane? | The original answer to this question is of course correct.
You are wrong to assume that the "downward pressure" (or better said downward momentum of air) *dissipates* before reaching the floor. In fact it *disperses*. That means the momentum transferred by the wings onto few air molecules is then spread by molecular collisions to many more molecules. Each molecule carries a much smaller downward momentum, but the much larger number of molecules carrying some imposed downward momentum is much larger. Therefore the net downward momentum is equal and preserved when being transferred to the floor.
Conservation of momentum is one of the most fundamental laws of classical mechanics, therefore its sum always has to cancel in a closed system.
The situation is slightly different when the airplane has an open cargo latch. In this some of the downward momentum can "escape" the plane before being transferred to the floor. Therefore, the plane would weigh somewhere in between the empty plane and the plane with sitting bird, depending on the size/geometry of the opening.
**edit:**
I see that you have edited your question to include your experiment after I wrote my comment. Again, your expectation is wrong and the counterweight will certainly keep the balance leveled because the weight of the airtight can will stay the same. You would see a quick fluctuation when the drone accelerated upwards, but it will return to balance once the "cruising altitude" is reached and the drone maintains a level flight.
**edit 2:**
I wrote an explanation further down [here](_URL_0_) which might explain the problem of your expectation. Since it might get buried let me quote myself:
> Also, air does not have to show a net flow in order to carry momentum from one place to another. This is the reason why waves can transport momentum without net transport of matter over large distances.
If you compare a hovercraft (floating on its ground effect cushion) and a helicopter (hovering at its ceiling altitude) the difference should be more clear. Both can hold their altitude by imposing downward momentum onto the air. In both cases the momentum has to be finally transferred to the ground. The difference, however, lies in the "fate" of kinetic energy (i.e. a net downward flux of air). While the hovercraft will generate this flux, leading to compression of air on the ground and local force acting on the ground (resulting in increased air pressure directly below its cushion) the air flow generated by the helicopter is dispersed and the kinetic energy of the air has dissipated before it reaches the ground. Nevertheless, the momentum is still transferred onto the ground, but now in a near infinite area. Therefore no net pressure increase could be measured on the ground below the helicopter. | [
"The television series \"MythBusters\" investigated the question in a 2007 episode, testing it both with a box of pigeons and again with a model helicopter. They concluded that the contents being in flight made no difference to the weight, and theorised that the downdraft of air from the wings or rotors pressed dow... |
Before the system broke down, how effective was enforcement of the parole system in the American Civil War? | I'm still looking to find a complete answer, but I came across this fact that I didn't know before I started researching. Apparently there was a scale of which soldiers could be exchanged. For example, a General was worth more than one private in a one for one swap. I think of it like a deck of cards in that you aren't going trade an Ace of Spades for a two of clubs. Because of this,there were weights assigned to each rank/grade.
The following was pulled from the Dix-Hill Cartel of 1862 which goverened how prisoners were exchanged and the terms of their parole. A common practice was for men to be paroled and once they were exchanged they would be able to rejoin their units. [Source](_URL_0_)
A general commanding in chief or an admiral shall be exchanged for officers of equal rank, or for sixty privates or common seamen.
A flag officer or major-general shall be exchanged for officers of equal rank, or for forty privates or common seamen.
A commodore carrying a broad pennant or a brigadier-general shall be exchanged for officers of equal rank, or twenty privates or common seamen.
A captain in the Navy or a colonel shall be exchanged for officers of equal rank, or for fifteen privates or common seamen.
A lieutenant-colonel or a commander in the Navy shall be exchanged for officers of equal rank, or for ten privates or common seamen.
A lieutenant-commander or a major shall be exchanged for officers of equal rank, or eight privates or common seamen.
A lieutenant or a master in the Navy or a captain in the Army or marines shall be exchanged for officers of equal rank, or six privates or common seamen.
Masters' mates in the Navy or lieutenants and ensigns in the Army shall be exchanged for officers of equal rank, or four privates or command seamen.
Midshipmen, warrant officers in the Navy, masters of merchant vessels and commanders of privateers shall be exchanged for officers of equal rank, or three privates or common seamen.
Second captains, lieutenants or mates of merchant vessels or privateers and all petty officers in the Navy and all non-commissioned officers in the Army or marines shall be severally exchanged for persons of equal rank, or for two privates or common seamen, and private soldiers or common seamen shall be exchanged for each other, man for man.
| [
"At the start of the civil war a system of paroles operated. Captives agreed not to fight until they were officially exchanged. Meanwhile, they were held in camps run by their own army where they were paid but not allowed to perform any military duties. The system of exchanges collapsed in 1863 when the Confederacy... |
the need to pee and proximety to the toilet? | It has to do with "Pavlovs Dog", basically we're so used to or "conditioned" to associate the toilet with urinating. | [
"Urine diversion toilet designs generally require men to sit or squat while urinating in order to avoid unhygienic splashing of urine. In cultures where men prefer to stand for urination, urinals are a good complementary solution. Urinals – widely used by men at public toilets, restaurants, schools, etc. – work as ... |
how do political polling places find people to use for their data? | This is a very valid question. Obviously they didn't do a great job of this in 2016.
There are different methods, from talking to people in the street "randomly" (that would depend on what part of town you're in, and time of day, etc). letters to houses and hope people answer randomly. The best method is by calling on the phone, but now with caller ID and lack of landlines, that is not as reliable as it once was. I know I don't answer anything that doesn't identify the caller, and I usually skip calls that are labelled as survey because in my experience the "survey" is instead going to be asking stupid things like internet access preferences, obviously on behalf of a particular vendor, not on a topic like national policy preferences. And sometimes people answer based on what they would do if they actually show up to vote on election day, but they never actually vote.
On actual election day, pollsters will stand outside certain voting sites and ask people who are leaving who they voted for, this is usually pretty accurate. | [
"A poll aggregator is an entity that tracks and aggregates, often but not exclusively by averaging, individual polls conducted by different organizations in order to gauge public sentiment on key civic issues such as the approval rating of a major political figure (e.g., president, prime minister, monarch, governor... |
what is a viral vector? | A vector, terms of biology, is an organism that transmits something from one place to another. In the case of a viral vector, a virus is being used to transmit genetic elements or the production of some biologically-relevant component between cells or organisms.
One example of a viral vector would be a non-harmful virus (only a small fraction of viruses cause harm during infection), which has been genetically modified to deliver DNA encoding a protein that a person otherwise lacked. | [
"Viral vectors are tools commonly used by molecular biologists to deliver genetic material into cells. This process can be performed inside a living organism (\"in vivo\") or in cell culture (\"in vitro\"). Viruses have evolved specialized molecular mechanisms to efficiently transport their genomes inside the cells... |
why is assaulting a cop more serious than assaulting anyone else? | Part of the reason is that police carry weapons. It may also have something to do with Police represent the law, and an assault on a police officer is therefore an assault on the law (older thinking?). That is just speculation though. | [
"The survey also shows that blacks are bigger victims of assault by police. The National Victimization Survey shows that in 2009, 6.5% of blacks who had suffered an aggression as aggressors police or private security guards (who are often working in the police off duty), compared with 3.7% of whites. \n",
"Violen... |
How did the first person with a contagious disease get infected with it? | infectious diseases evolve just like any other creature, and by doing so they also enable themselves to explore new places to live and be successful.
If the disease stays on one host, there is not really a patient zero, since evolution is a highly parallel and complex and many times rather continuous process. What we can check is if we find the first *record* of a certain form of a disease. Chances are high though that what is described is actually an existing and well known disease that just evolved a tiny bit to manage to spread to a different part of the body.
However sometimes a disease manages to evolve in a way that it's able to infect a new species. Then it is somewhat possible to trace the spreading of the disease on the new hosts back to where it initially started (an area, a city, sometimes even a single person, the patient zero).
I won't go into the evolution tree because I'd be speculating, but I am very sure such a thing exists. | [
"When the Black Death bubonic plague reached Al-Andalus in the 14th century, the Arab physicians Ibn Khatima (c. 1369) and Ibn al-Khatib (1313–1374) hypothesised that infectious diseases were caused by \"minute bodies\" and described how they can be transmitted through garments, vessels and earrings. Ideas of conta... |
Why was Sufi Islam particularly strong in Ottoman Empire when compared to other places? | What makes you think that it was? Sufism was incredibly popular long before the rise of the Ottomans. It was and is extensively practiced, for example, in the Indian subcontinent and in South East Asia. Sufism was embraced by the Ottomans but I'm not sure I would describe it as being quantifiably stronger than in other places. I'm certainly not familiar with any data to suggest that it may have been. It was embraced by the state, but that was certainly true elsewhere as well. | [
"Sufism was an important factor in the historical spread of Islam, and in the creation of regional Islamic cultures, especially in Africa and Asia. Recent academic work on these topics has focused on the role of Sufism in creating and propagating the culture of the Ottoman world, including a study of the various br... |
how do celebrities get social media handles with their names? do companies like twitter or instagram assist celebs in getting a marketable handle? | Pretty much. They just message who ever owns one of those handles and just offers them money. | [
"There are many examples of celebrities building a brand for themselves over some sort of social media platform. In fact, it is rare to see an athlete or celebrity without a social media page whether it is twitter or instagram. Celebrities use these outlets as ways of branding themselves, by showing people their li... |
So, I was dumping out an old bottle of generic dayquil, and found two clear crystals, can you explain what I found? | Could you give me a sense for how big they are? It'd also help to get a picture from another angle, possibly in some lighting with a little less glare.
The generic answer is: I don't know, and its difficult to tell without some analytical tests.
I can be more specific than that, though. Dayquil and its ilk, whether or not its the generic kind, have relatively few ingredients and it should be pretty easy to figure out whats what in this case. You're right, though, these are definitely crystals. I just pulled a bottle of generic dayquil out of my own cabinet, here is my ingredient list:
Acetaminophen, Dextromethorphan HBr, Phenylephrine HCl, butylated hydroxyanisole, edetate disodium, FD & C yellow #6, flavors, glycerin, monobasic sodium phosphate, polyethylene glycol, propylene glycol, purified water, saccharin sodium, sucrose, xanthan gum
I immediately rule out edetate disodium or EDTA (abundance), the dyes (color), flavors (abundance), glycerin (melting point), polyethylene glycol (doesn't make crystals that nice), propylene glycol (melting point), water (melting point), and xanthan gum (poor crystallizer). Those I'm sure of. I'm also going to rule out butylated hydroxyanisole since its pretty soft and would leave a residue on your hand and I'm guessing you would've mentioned that.
I'm also going to rule out dextromethorphan and phenylephrine because of abundance, there's only about 200 mg of each of those in the bottle total, which wouldn't have made crystals large enough for you to notice.
That leaves us with: Acetaminophen, sodium phosphate, saccharin and sucrose (table sugar).
I'm betting against acetaminophen. Its extremely soluble in the amounts its present in the bottle and there really isn't alot of it. I'm also betting against sodium phosphate. Its difficult to get firm numbers, but I'm betting there isn't enough of it in the bottle. Between saccharin and sucrose, I'm picking sucrose (table sugar) because of the shape of the crystals. Saccharin seems to avoid the rhombic type crystals in the pictures you showed. | [
"Examples of liquid crystals can be found both in the natural world and in technological applications. Most contemporary electronic displays use liquid crystals. Lyotropic liquid-crystalline phases are abundant in living systems but can also be found in the mineral world. For example, many proteins and cell membran... |
If I increase the Frequency of a sound wave will it travel further over a distance? | If I understand you correctly, you are asking whether the rate at which the intensity/loudness of a wound wave decays over a finite distance depends on its frequency? If so, the answer is yes. If so, the answer is yes. The simplest model for this attenuation (weakening) of the wave in a fluid such as air is called [Stokes' Law](_URL_0_) and it states that the amplitude of a plane wave will decay exponentially as e^-a , where a is the attenuation factor. This factor a in turn is proportional the square of the frequency of the wave. This suggests that high frequency waves decay much faster than low frequency waves. This is for instance why the low frequency sounds whales produce can carry over such long distances in the ocean. | [
"The below discussion is from Landau and Lifshitz. If the amplitude and the direction of propagation varies slowly over the distances of wavelength, then an arbitrary sound wave can be approximated locally as a plane wave. In this case, the velocity potential can be written as\n",
"BULLET::::3. The interactions b... |
What's the difference between the Holocaust and the Shoah? | Shoah is a Hebrew word, which means "disaster." Holocaust is an English word derived from Greek, and as you pointed out, it means a sacrifice that's entirely consumed by fire (as opposed to other sacrifices, where only part is burned up and the rest is eaten), so it came to mean a total massacre. They refer to the same event. Because "Shoah" is the word that Jews designated for themselves, some historians use it too, as part of letting oppressed peoples define their own history, similar to how historians increasingly use native words when writing about native Americans, instead of the words chosen by colonists. | [
"Mizrahim is an umbrella term for the Judeo-Arabic and Judeo-Persian speaking Jewish communities from the Middle East, North Africa and Central Asia. Although Mizrahi Jews are not descended from the Jews expelled from the Iberian Peninsula, they are also called Sephardi to contrast them to the Ashkenazi culture and... |
Did anyone from past eras produce writings solely for the purpose of future historians to study? | Many people do keep diaries for the purpose of reading them later and remembering/keeping a record of past events. They can be valuable for historians, especially if the diarist is unusual for their place/time in keeping a diary. Martha Ballard is kind of a canonical example of this -- she was an 18th-century midwife in Maine who kept a diary, which would form the basis [for this book](_URL_0_). Now, Ballard was certainly unusual in being a literate woman during her time period who also kept a diary, so there's a great deal of argument over how representative her particular experiences were -- the book was something we read in my historiography class in grad school as it stimulated discussion of those questions.
Moving to more typical diarists, the example from my field that comes to mind is Samuel Pepys, who kept a diary for 1660-1669. Pepys' diary is extensive and wanders quite a bit, but there are certainly indications in it that he realized that he was writing for posterity. He was involved in naval administration, and also lived through a tumultuous time in English history, and there are definitely descriptions of large events (the fire of London, the Great Plague) that seem written with an eye toward posterity; but he also records mundane events like the time he woke up in the morning and personal events like his pursuit (today we'd call it sexual assault) of servants. There diary has been published in multiple [editions](_URL_2_), including one that has portions of it [you can read online](_URL_1_). | [
"Another characteristic of the histories of the period is that they borrowed heavily from other writers, often directly copying entire works as their own. For example, Henry of Huntingdon's \"History of the English\" is only one quarter original, relying in many places on Bede's \"Historia Ecclesiastica\". This pro... |
We've seen pictures of Stellar Nurseries, huge nebulae created by the death of a star. How can the mass of a single star create a nebula that goes on to create many new stars and accompanying planets? | I think you might be confusing stellar nurseries, like the [Orion Nebula](_URL_1_), which is a huge cloud that had a mass thousands of times the mass of our Sun before any stars formed in it, with planetary nebulae, like the [Ring Nebula](_URL_0_) which are the expelled layers of old/dying stars. Planetary nebulae do not go on to create new stars, at least not without the contribution of other stars/clouds. | [
"Some of these collapsing stars can be particularly massive, and can emit large quantities of ionizing ultraviolet radiation. An example of this is seen with the Trapezium cluster. Over time the ultraviolet light from the massive stars at the center of the nebula will push away the surrounding gas and dust in a pro... |
why is zoe quinn being defended? | She is a person in a creative field open to commentary by the internet. There are thousands of people in the U.S. alone who work in various forms of media that deal with mean comments and threats against their person. The true professional looks at this feedback and compares it to the quality of their product. The maker of any piece of media knows if it is of high quality within the bounds of their resources. The issue is that her game, "Depression Quest", is a sub-par, text-based game that was greenlit on Steam and given high critical praise by writers she was tied to romantically. And instead of dealing with the criticism of her product and conduct like a professional she claimed the victim card and demanded that any negative word about her be silenced. The white-knight syndrome of the "enlightened male" kicked in and we now have this cluster fuck. | [
"Despite her earlier claims that she feared violence or death in her home country – an assertion that she had repeated in subsequent interviews – Al Khalifa returned to Bahrain in late 2001 to visit her family. She stated that she and her family were concerned about \"violence aimed at people of Middle Eastern desc... |
how is it that for two months california has had a methane leak and it won't be fixed until spring? | In order to fix the leak, workers have to drill 8500 feet down into the earth, find the underground well, and pump it full of concrete. This process will take months, and can't realistically be sped up.
EDIT: For a more detailed answer, see u/WalterLSU below.
EDIT 2: More info with pictures:
_URL_0_ | [
"A gas leak from the underground Aliso Canyon gas storage started in October 2015 releasing methane in an uncontrolled fashion. By December 2015, thousands of people from Porter Ranch had been temporarily relocated and the leak had added more than 150 million pounds of methane to the atmosphere. The NGO Environment... |
When and why did English orthography stop using Þ (thorn) and ð (eth)? | As far as thorn goes, early English printing presses used imported type that didn't include thorn. Printers would either use "th" or use a y as a thorn, which wasn't too much of a stretch (a handwritten thorn looked like a y). Sort of like how typewriters would use the same character for lowercase "L" and "1".
That's how we got "ye" for "the" in old books (I've never seen it after the seventeenth century) and modern pretentious signage ("ye olde coffee shoppe"); the y is really a thorn, and it was pronounced "the", not "yee".
So really, we still use thorn, but only on pretentious signs, and we mispronounce it as a "y." | [
"The letter thorn was used for writing Old English very early on, as was ð; unlike ð, thorn remained in common use through most of the Middle English period. Both letters were used for the phoneme , sometimes by the same scribe. This sound was regularly realised in Old English as the voiced fricative between voiced... |
Why does beta plus (β+) decay happen in proton-proton chain reactions; why don't the two protons just form helium instead of deuterium? | Helium-2 is unbound, so it decays on extremely short timescales. The only way to combine two protons into a bound system is to rely on the weak force to change one of the protons into a neutron, producing a deuteron.
This is not a beta decay, it's a nuclear reaction which involves the weak force. That's why the probability of it occurring is so small, and why it forms a bottleneck for the entire pp-chain. | [
"Beta decay is characterized by the emission of a neutrino and a negatron which is equivalent to an electron. This process occurs when a nucleus has an excess of neutrons with respect to protons, as compared to the stable isobar. This type of transition converts a neutron into a proton; similarly, a positron is rel... |
Has anyone ever become a Saint in their lifetime? | I don't believe that has ever happened. An integral part of being declared a saint (canonized) in the Catholic Church is that the person is declared to be in Heaven, so that precludes still being alive on Earth. The Dominican priest (and professor) who inspired my username asserted that the Church waits for the subject to be "safely dead" before beginning the canonization process. He was joking, but only to an extent. Having the subjects story be complete is important, so that you would avoid a saint denying God's existence or the like in the twilight of their life.
None of this is to say that the Church always had a set procedure in place. The modern procedures were revised in 1983, and before that in 1917 and 1914. Before that you have to basically go back to the 16th century. Before *that* things were...looser. This laxity was problematic, leading to the canonization of some people that may not have existed. A number of people who had been declared saints that had dubious historicity were removed from the calendar of saints by the Catholic Church a number of years ago, but did not have their saintly status changed. | [
"Other young people have been canonized as saints. Fourteen-year-old Saint Pancras was beheaded in 304 A.D. after he became a Christian, and Saint Ponticus was fifteen when he was thrown to the lions in 177 A.D. The youngest saint canonized by the Roman Catholic Church in modern times is Maria Goretti, who died in ... |
when a body decays, where do those white maggots(?) suddenly come from? | Flies are really good at detecting rotting meat, land on the meat to eat and breed and lay eggs, then the eggs hatch into maggots. Flies are tiny and quick so you won't really see them on a timelapse video. | [
"Active decay is characterized by the period of greatest mass loss. This loss occurs as a result of both the voracious feeding of maggots and the purging of decomposition fluids into the surrounding environment. The purged fluids accumulate around the body and create a cadaver decomposition island (CDI). Liquefacti... |
why is the world not on a universal time? in other words why is it not "13:00 pm" all around the world - some would come to see it as daytime afternoon, others late afternoon, and yet others early morning. | The military uses this for large scale operations, in their use of "Zulu Time".
"Zulu" time is that which you might know as "GMT" (Greenwich Mean Time). Our natural concept of time is linked to the rotation of the earth and we define the length of the day as the 24 hours it takes the earth to spin once on its axis.
As time pieces became more accurate and communication became global, there needed to be a point from which all other world times were based. Since Great Britain was the world's foremost maritime power when the concept of latitude and longitude came to be, the starting point for designating longitude was the "prime meridian" which is zero degrees and runs through the Royal Greenwich Observatory, in Greenwich, England, southeast of central London.
As a result, when the concept of time zones was introduced, the "starting" point for calculating the different time zones was/is at the Royal Greenwich Observatory. When it is noon at the observatory, it is five hours earlier (under Standard Time) in Washington, D.C.; six hours earlier in Chicago; seven hours earlier in Denver; and, eight hours earlier in Los Angeles.
Unfortunately the Earth does not rotate at exactly a constant rate. Due to various scientific reasons and increased accuracy in measuring the earth's rotation, a new timescale, called Coordinated Universal Time (UTC), has been adopted and replaces the term GMT. | [
"Because of the division of the globe into time zones, the new year moves progressively around the globe as the start of the day ushers in the New Year. The first time zone to usher in the New Year, just west of the International Date Line, is located in the Line Islands, a part of the nation of Kiribati, and has a... |
Is there actual evidence that the ancient Irish sucked their kings' nipples to display fealty? | Thank you for posting this as it's a really good question. I'm by no means an expert on Irish (especially early-Irish) history so I would wait until somebody else gives you a definitive answer on this. As the article you link to suggests, it does appear that sucking nipples was a means to pledge loyalty in pre-Christian Ireland. Saint Patrick mentions in his *Confessio* that when he fled Ireland, he was offered passage on a boat by some sailors, although he refused to suck their nipples. Interestingly, Patrick considers this to be a barbarian custom and that he refused "for fear of God."
[Here is the relevant translation of the text](_URL_0_). This translation here prefers the term "breast", but I think it's clear that the general idea was that this symbolised submission and loyalty to another. I can't read Latin unfortunately, but somebody else could shed more light on whether this is an accurate translation.
When this practice died out is something that I can't answer I'm afraid. Nor can I answer your question about nipple severing any better than the article you linked does. I hope my little contribution helps anyway. | [
"No further mention is made of Dionotus by Geoffrey of Monmouth, but a small group of these women defied kings Wanius and Melga of the Picts and the Huns, who attempted to have intercourse with them. The women were slaughtered for their defiance and the kings invaded Britain from Albany. Britain, due to the war led... |
Resources to learn about US colonization/imperialism in Latin America | [_URL_0_](_URL_0_)
How to Hide an Empire is a pretty good source for American influences in Latin America, there is some focus on the Pacific islands and the Philippines but that is also pretty closely tied to Latin America in terms of Spanish influence | [
"BULLET::::- The Summit of the Americas in the Context of US Imperialism (April 2015). \"Scholar and activist Gerald Horne traces modern-day US foreign policy in Latin America to its colonial roots.\" \"The Real News\"\n",
"Murdo J. MacLeod is a Scottish historian of Latin America, publishing extensively on the h... |
Why doesn't carbon monoxide turn into carbon dioxide when additional oxygen becomes present? | Imagine you're skateboarding down a road that goes downhill into a valley, uphill a bit, then downhill into a second deeper valley. Ordinarily you'd go all the way to the bottom, but if for some reason you got stopped in the first valley, you'd be stuck there: you'd need a push to get over that second hill and get to the bottom.
In this analogy, unburned fuel is the top of the first hill, carbon monoxide CO is the first valley, and carbon dioxide CO2 is the second, lower valley. The height of the hill represents the amount of chemical energy remaining in the molecule. If there's not enough oxygen to complete combustion, you get "stuck" at carbon monoxide. To continue to carbon dioxide, you need to add energy to the molecule to "push it over the hill". Heat up a mix of CO and O, and it will burn to form CO2. CO was actually used as a fuel gas in the old days, but it's so toxic we don't do that anymore.
But maybe you don't have to climb that second hill. Maybe there's a road that goes *around* it instead! This is what a catalytic converter does: it provides an alternate chemical path for CO- > CO2 combustion that requires less energy input. In the atmosphere, a molecule called the "hydroxyl radical" (OH) also naturally helps to convert CO into CO2 without added heat, but there's very little OH in the atmosphere so this process is pretty slow (months). | [
"Carbon monoxide has a higher diffusion coefficient compared to oxygen, and the only enzyme in the human body that produces carbon monoxide is heme oxygenase, which is located in all cells and breaks down heme. Under normal conditions, carbon monoxide levels in the plasma are approximately 0 mmHg because it has a h... |
Why does cellular regeneration degrade as an organism ages? | This was recently discussed in the comments section on a post about an anti-aging substance found on Easter Island. I'll do my best to repeat what I learned.
DNA has empty sections reserved for errors when replicating. Each time DNA is replicated these lengths, called telomeres, get shorter. For most cells, replication can only occur 52 times (called the Hayflick somethingorother) because the telomeres become shorter and shorter until there is no more room for errors. At this point the cell, if it tried to replicate this DNA strand, would simply be creating a cancerous cell. All the normal errors would be likely expressed in genes, rather than in telomeres.
Take this answer with a block of salt. This is purely from memory, and the experience of someone who works with computers, not biology. | [
"\"Regeneration\" in a living system refers to the general compensation for losses and degradation in the various components and processes in the system. This covers the thermodynamic loss in chemical reactions, the wear and tear of larger parts, and the larger decline of components of the system in ageing. Living ... |
the whole jeffrey epstein situation | So he was charged with sexual trafficking of minors and was awaiting trial in jail. Two weeks ago he was found in his cell unconscious with neck injuries, he was placed on suicide watch and released a few days later. Today he was found dead, reported hanging himself. Those are the facts.
What's odd is he was taken off the suicide watch at all. He should have stayed on it and there are even doubts about it being a suicide. So that leaves us to ask why would he be taken off suicide watch?
It is all strange we will see what happens as more facts come out. As of now the US attorney general has ordered an investigation into the matter. | [
"Epstein's lawyers urged the court to allow Epstein to post bail, offering to post up to a $600million bond (including $100million from his brother, Mark) so he could leave jail and submit to house arrest in his New York mansion. Judge Richard M. Berman denied the request on July 18, saying that Epstein posed a dan... |
[meta] what if i told you that you could get the most out of [eli5] if you brought an already correct answer to a question that interests you, but you just need someone to *explain* it to you. | Another suggestion, stop down voting correct answers that are hard for you to understand, even hard for anyone to understand. Save your down votes for "bad explanations" of correct answers or "incorrect answers".
This subreddit should be about up voting great explanations of correct answers, and downvoting correct answers stands in the way of that. Leave the correct answers alone and just ask questions about them, eventually it can lead to a great explanation of a correct answer to an interesting POST. Up vote that response. | [
"BULLET::::5. If you try to encourage more openness, and at first others are unresponsive or hesitant to participate, consider asking someone you trust after the meeting if there is something that you might have missed or could have done differently to achieve the desired result\".\n",
"Ward is credited with the ... |
Did the United States government ever consider allying with the Axis powers in WWII? | No chance as long as Roosevelt was president. No real chance even without him, for that matter. There were some "pro-Axis" men in congress, but their numbers were small. The pro-Axis faction was more focused on keeping America out than on getting them in on Germany's side. They tended to focus on the "warmongering" of Churchill and on promoting isolationism.
Also, remember that long before the USA officially joined the war, they were involved in arming Britain and otherwise supporting the Allies. | [
"In December 1941, the United States of America declared war on the Axis powers after the attack on Pearl Harbor. In January 1942, the Third Consulting Meeting of Chancellors of the American Republics met in Río de Janeiro as the U.S. wished other American nations to break relations with the Axis powers. Argentina,... |
why does david cameron want mandatory porn filters for uk internet users? | Information control. Australia's government tried to same thing a couple of years ago but it failed. Turned out that porn was just going to be the first step and then after that it was going to be everything the government didn't like. Whoever controls the information has the power. The idea is to get their foot in the door by saying it's about porn, specifically child porn (which it won't do anything to stop since you don't just find that with random searches) and then after that you just quietly expand it to cover everything else. | [
"In 2013, Prime Minister David Cameron introduced plans to filter internet pornography by default in the UK. By the end of 2014, access to internet pornography was blocked unless subscribers specifically chose to 'opt out' by contacting their ISP. This was done in an effort to reduce the number of children having a... |
Is there any evidence of trench warfare in the Civil War before Petersburg? | I would caution against the anachronistic use of the term 'trench warfare' in the American Civil War. The term is typically used to describe the Western Front of WWI, where the numbers, firepower, and dispositions of the combatants allowed the continuous front lines to extend from the Alps to the English channel. This did not happen in the American Civil War; the armies were not large enough to anchor their both their flanks on impassable obstacles, and did not have the firepower to prevent a frontal breakthrough with assurance. The technology of the two wars is very different, and they were fought by very different societies. The social-military conditions of the American Civil War were unique to their time and place, and should be understood on their own terms.
That said, there is indeed precedent for the use of entrenchments before the siege of Petersburg, really to the earliest days of the war. Really, it'd be easier to list the battles where no entrenchments were used. After the Battle of Bull Run, Joseph E. Johnston entrenched his army before he fell back to his base on the Rapidan Rappahannock river line; this position famously yielded the 'quaker guns' (logs painted to look like cannons) that baffled Union scouts and generals for months. Lee made extensive use of trenches during the Peninsula and Seven Days campaigns as an economy of force measure, allowing him to defend Richmond with minimal forces while he concentrated most of his army for the hammer blow to the north. McClellan was (in)famously trench-happy, establishing very strong positions to cover the slow, methodical advance to the next position, where he could dig in, bring up his heavy guns, and repeat the process. Joe Hooker had designed the Chancellorsville campaign around forcing Lee to attack his entrenched infantry, and Union positions on Cemetery Hill at Gettysburg were well fortified. The Overland campaign leading up to the siege of Petersburg saw field fortifications play a pivotal role in just about every battle. This is a very bumper sticker summary; I can go into more detail if you want.
However, like I mentioned above, I would not describe this as trench warfare, and I don't think the use of entrenchments during the American Civil War meaningfully anticipates the developments of the First World War. While the prevailing view is that the increased range of the rifle musket forced troops to seek shelter in the earth to survive, I agree with Earl J. Hess, who has authored a series of books on the use of field fortifications during the Civil War. He strongly denies the claim of increased firepower; the available evidence indicates that engagements largely stayed within the range of smoothbore muskets, and that casualty rates were broadly similar. The necessity of accurate range estimation to hit anything past a hundred yards and the near total lack of marksmanship training for the rank and file severely limited the application of the new weapon.
Rather, the America proclivity towards entrenchments arose from a variety of less material causes. In the east, the inability of either army to destroy the other in a battle of annihilation meant they remained in contact much longer than European armies of the same period. Moreover, the prewar education of the engineers, who comprised the best and brightest of the pre war Regular Army, was directed by Dennis Hart Mahan of West Point, who placed great emphasis on the power of field fortifications. Mahan understood that American armies would largely be composed of militia and short service volunteers, whose forbearance under fire and the press of cold steel would be uncertain, and that prepared positions would be useful for stiffening otherwise shaky troops. The inverse of this turned out to be that said shaky troops would become very reluctant to assault field fortifications; by the time of the Overland campaign, 'worn out' regiments could flat out refuse to assault entrenchments, or make only a token effort.
For the full story, read Earl J. Hess's three volume history of entrenchments in the Civil War.
*Field Armies and Fortifications: The Eastern Campaigns, 1861-1864*
*Trench Warfare under Grant and Lee: Field Fortifications in the Overland Campaign*
*In the Trenches at Petersburg: Field Fortifications and Confederate Defeat* | [
"Although mainly a siege, it was not unusual to find an extensive trench system inside and outside the city of Sarajevo during the siege of 1992–1996. It was used mainly for transportation to the frontline or to avoid snipers inside the city. Any pre-existing structures were used as trenches; the best known example... |
Does adding more heat to a pot of boiling water make it cook things faster? | This is the thing about latent heat. No matter how much heat you give to a pot of water, until all of the water has turned to steam, temperature of that vessel will not cross 100 degrees Celsius (212 F). More heat will boil the water quickly, for the same quantity of water | [
"Sometimes a supply of an unknown amount of instant hot water is required, for example when cooking risotto boiling water must be added instantly as needed. This can only be achieved with a kettle by boiling the maximum amount that can be needed; in cases of this nature the instant water heater, which heats and dis... |
Why were the Gracchus Brothers allowed to be People's Tribunes? Weren't they patricians? | No, the Gracchi were members of the *gens Sempronia*, an old plebeian *nobilis* family. The senatorial class had included plebeians for centuries by the time of the Gracchi, since the resolution of the Conflict of the Orders, and by Caesar's time the patrician order had essentially ceased to exist. The vast majority of senatorial families were plebeian, and you really sort of have to go out of your way to find patricians, they're fairly unusual | [
"During the early years of the republic, the Plebeians were not allowed to hold magisterial office. Neither Tribunes nor Aediles were technically magistrates, since they were both elected solely by the Plebeians, rather than by both the Plebeians and the Patricians. While the Plebeian Tribunes regularly attempted t... |
what it is to default on a debt. what are the consequences? | Let's forget about bonds for a minute, and think about a personal loan which you might take out from the bank (which is essentially the same thing on a smaller scale).
No one can force you to repay that loan. If you fail to pay it, though, then your credit rating will suffer. You will have to pay more to borrow in future, or you may find that you simply can't borrow at all. The bank may send bailiffs to your house to recover what they can (or, more likely, sell the debt to someone else who will send bailiffs round). If you are unable to pay, then you have options available to you such as bankruptcy, which is effectively an agreement that you'll pay what you can, and the bank will let you off of the rest.
A bond is exactly like that. If a country fails to pay what's due, then it will find it harder to borrow in future, just the same as you would. You can't just send the bailiffs around - there is no legal way force a country to repay. But it's in the country's interests to pay if possible, if it wants to be able to continue to borrow at a reasonable rate and run its economy effectively. | [
"Default occurs when the debtor has not met its legal obligations according to the debt contract, e.g.- it has not made a scheduled payment, or has violated a covenant in the debt contract. Default may occur if the debtor is either unwilling or unable to pay its debt. This can occur with all debt obligations includ... |
how is the sat scored? | It has been a while since I have taken the SAT and it might have changed more since I have taken it. First there is a raw score. For this score in the multiple choice section, you get a point for each question you get right, zero points for questions that you did not answer and lose 1/4 of a point for every wrong answer. For the essay, two graders will give it a score ranging from a 1 to 6 where 1 is terrible and 6 is fantastic. They will then combine the two scores together. Once all the raw scores are calculated, they will standardize them based on others who have taken the test. So, if your raw score for verbal ends up being at the 50th percentile, you will get a 500 for verbal. If you are in the 99th percentile for verbal, you will get an 800. After adding all the section scores together, there will be the final score
Tl:Dr they give you a raw score and then standardize it with others. | [
"Research suggests that the SAT, widely used in college admissions, is primarily a measure of \"g\". A correlation of .82 has been found between \"g\" scores computed from an IQ test battery and SAT scores. In a study of 165,000 students at 41 U.S. colleges, SAT scores were found to be correlated at .47 with first-... |
How were Americans treated/viewed in Japan (Tokyo specifically) during the Taishō era? (1912-1926) | > Were US students allowed to attend the University of Tokyo?
I don't know if they were allowed earlier, but the first non-Japanese American to graduate from the University of Tokyo was Don Cyril Gorham, who graduated in March 1941. So if there were any American students in the Taisho period, they didn't graduate at least. | [
"The Japanese American Memorial to Patriotism During World War II is a National Park Service site to commemorate the experience of American citizens of Japanese ancestry and their parents who patriotically supported the United States despite unjust treatment during World War II.\n",
"The phrase appears as an impo... |
Why did the German Army invade Netherlands in World War II, when in World War I, Dutch armed neutrality deterred the Germans? | Hello! As a Dutchman this post stood out to me, while I am not an expert on WW2 history, I will explain the history behind the German invasion of the Netherlands as I understand it.
**World War 1**
The Netherlands maintained an armed neutrality throughout WW1 and declared itself to be neutral at the outbreak of the war, like Belgium. And just like Belgium, the Netherlands was militarily no match for the German Empire. Unlike Belgium however the Netherlands did not border any nations of the Allies, and there would be little military gain for the German Empire had it invaded the Netherlands. Not only would it have enlarged the area that needed to be occupied, it would have driven the newly formed Dutch government in exile to join the Allies, who could then make use of resources from the Dutch colonies in the Americas and Asia. The Netherlands were also an important trading partner for Germany during the war, as the Empire's waters were blockaded by the Royal Navy. Invading the Netherlands in WW1 was thus not seen as something that would be advantageous by the Germans.
**Interbellum**
During the 1920s and 1930s the Dutch economy would be hit hard by the Great Depression. Investment in the military effectively came to a standstill until then end of the 1930s. While the military brass of the Netherlands was aware of the aged equipment and the importance of tanks, anti-tank weapons and sub-machine guns, none of these weapons were purchased. Only in the latter half of the 1930s did modernisation begin, and by that time many countries such as the United Kingdom, France and Germany were already busy with their own rearmament programs and could thus not supply new weapons in any great numbers.
When the Germans invaded the Netherlands on 10 may 1940, the Dutch soldiers were armed with 45 year old rifles, machine guns dating back to WW1, no tanks, 39 armoured cars, too few mortars and only 52 pieces of post-WW1 artillery. The military had been able to acquire new anti-tank guns and anti-aircraft guns however. The airforce was in a slightly more modern shape, flying a mixture of biplanes and more modern fixed-wing aircraft, but had to deal with unpreparedness and only 70 modern planes in total. When the troops were mobilised in August, not much time was spend training the troops, most soldier spend their time building bunkers and trenches instead of actually gaining military skills.
**World War 2**
The German plan to invade of the Netherlands was primarily born out of the failures of WW1. The Germans had been unable to defeat France, and this was partially attributed to the fact that the Belgian front had been to narrow in the rear. To solve this, the Dutch province of Zuid-Limburg would have to be invaded to give the Germans more space to manoeuvre. The Netherlands could also serve as a beachhead for the British, which was of course not favorable for Germany. While the Dutch and German armies would have been quite similarly armed in 1914, the Germans now greatly had the upper hand when it came to firepower and mobility. The German soldiers and officers were also more experienced due to fighting in Poland.
While the Dutch military put up a good fight and even won a number of battles, such as the Battle for The Hague and the Battle of the Afsluitdijk, they were unable to do much about German air superiority once the small Dutch airforce had been mostly destroyed. After the Bombing of Rotterdam, the Germans threaten to bomb Den Haag, Amsterdam, Utrecht and Haarlem if the Dutch government did not surrender, which it did. By the time the Netherlands capitulated on 15 May, half of the country was already taken by the Germans, and only in the province of Zeeland did fighting between Dutch and German soldiers continue for a little less than two more weeks, with the help of the Belgian, French and British forces. | [
"The Netherlands were able to remain neutral during World War I, in part because the import of goods through the Netherlands proved essential to German survival, until the blockade by the British Royal Navy in 1916. That changed in World War II, when Nazi Germany invaded the Netherlands on 10 May 1940. The Rotterda... |
describe the process of gaining weight. from ingestion to digestion and so on. | When you eat food, your body breaks down the larger nutritious molecules into simple glucose molecules. Glucose is the fuel that your body uses. The body takes a few steps to do this starting with physically grinding up the food with your teeth, then chemical breakdown with your saliva, then further chemical breakdown with stomach acid, and then further breakdown in the small intestine. Each type of nutrient molecule (carbs, fat, protein) is broken down with a different process, but in the end, the molecule is broken up into much smaller glucose molecules, which are absorbed into your blood through the small intestine.
The glucose molecules travel through the blood to enter individual cells where they are used to perform different functions in the cells. Your body needs a careful balance of glucose in the blood at all times. If glucose levels are low, cells can't function. If glucose levels are high, cells can be damaged.
Because of this, our body has a way of storing glucose molecules for later use. If the glucose levels get too high, the insulin hormone is released. Insulin pulls glucose out of the blood, and stores it in a molecule called glycogen, which is basically lots of glucose molecules chained together. Glycogen molecules get stored in the liver and muscles. Therefore the levels of glucose in the blood will decrease once insulin is released, thus saving your cells from damage.
If blood glucose levels get too low, the hormone glucagon is released. It does the opposite of insulin. It breaks off glucose molecules from the chains of glycogen, thus bringing your blood sugar levels back up. Glucagon and insulin keep your blood sugar levels balanced.
So now how do we get fat? There's only a finite amount of storage space for glycogen molecules. If they are full, then the body will start converting the medium-term storage glycogen molecules into long-term storage fat molecules. The fat molecules get stored in different locations throughout your body (exactly where is largely determined by genetics and gender). If your glycogen levels get low, then your body will convert fat into glycogen. This process takes a while, which is why it's not a good idea for the body to convert fat directly into glucose, and glucose directly into fat.
So knowing this, what does this tell us about losing weight? We should avoid foods that have lots of glucose molecules. These foods cause our blood sugar to spike, which causes an insulin release, which stores the energy, then causes our blood sugar levels to drop, which causes us to feel hungry again. The glucose molecules don't spend enough time in our blood to be used by our cells before being forced into storage. It's better to eat foods that "burn" slower, like long-chain carbohydrates (found in fruits, vegetables, and whole wheat bread), fats, and protein. These molecules shed glucose molecules into the blood slowly, thus they don't trigger an insulin response. This keeps your blood sugar levels more balanced, and keeps you feeling full longer. | [
"Santorio Santorio was a Venetian doctor who, in attempt to quantify human digestion, carefully measured his food/water intake and excretion weight over many years. To establish a mathematical relationship between food/water intake and excretion, Santorius designed a special chair that had a balance that weighed a ... |
What determines the frame of reference for us to feel acceleration? | You would feel the same force on you independent of the earth. If you were flying and accelerating you would feel the same force. It is only created through your inertia that "presses against the acceleration". Your inertia will keep you in place for whatever direction and speed you were moving when no force applied to you. A ball that is rolling has the inertia of rolling and would not stop if no force was applied to him.
Read [Newtons laws](_URL_0_) for more basic understanding. | [
"For a more complex example involving observers in relative motion, consider Alfred, who is standing on the side of a road watching a car drive past him from left to right. In his frame of reference, Alfred defines the spot where he is standing as the origin, the road as the -axis and the direction in front of him ... |
What weapons were popular with Vikings during raids? Did they ever use siege engines? What kind of armor was commonly worn? | > Did they ever use siege engines? What kind of armour was worn?
I wrote an answer about the phases of Viking raiding activity [here](_URL_0_), but whether for opportunistic profit or as part of a diversion strategy, Viking raiding parties aimed to be as highly mobile as possible. Despite what pop-culture neo-Pagans might want you to think, a successful Viking really wanted to avoid anything resembling a fair fight, or even a fight at all, as much as possible. Strategy was dependent on moving quickly, overwhelming small, local garrisons and slipping away again before a substantial response could be organised; anything that would require siege engines to capture would be far too long a stop, and far too significant a battle for anything short of the massive fleet which hits London in 850. That particular fleet overwhelms the Mercian army, but the Mercians delay the Vikings sufficiently that the West Saxon army is able to reach them and annihilate them. The Anglo-Saxon Chronicle documents a great number of occasions prior to the advent of the *burh* network when raiders hit an area, only to melt away by the time that a response is organised, or that a raiding army is finally caught up with and destroyed by the English.
Broadly speaking, early medieval Scandinavian wargear is similar to that used in England, and we have accounts from sources such as the *Anglo-Saxon Chronicle*, *The Battle of Maldon* and works of contemporary fiction like *Beowulf*. For the majority of individuals, weapons and armour would have been a spear and shield, probably a knife, and at most a helmet. Some individuals would likely have used javellins, and others may have used bows as well. Wealthier individuals may have had chainmail armour and more substantial helmets, and may have also carried swords. Again much of this depends on the period and purpose of the raiding. An opportunistic crew attacking an isolated monastery in the 820s may have only carried spears, shields and axes, whereas a major fleet like that in 850, or raids which were part of the 'Great Army's strategy in the 860s were likely to have been far more organised and, as a result, featured a higher proportion of well armed and armoured individuals. | [
"What is known is that they were used to provide covering fire while the attacking army was assaulting a fortification, filling in a ditch, and bringing other siege engines up to walls. Jim Bradbury goes so far as to claim torsion engines were only useful against personnel, primarily because medieval torsion device... |
Why can't surgeons always implant an artificial heart instead of giving a heart transplant? | The short answer is that the technology just isn't there yet.
The heart is often called a pump, but its not just a pump. It is two intelligent pumps.
It adjusts its stroke volume, its cardiac output, its heart rate, all automatically. If you need more blood, your nervous system can stimulate it to increase the forcefulness of the contraction and the rate of contraction. When you exercise, more blood ends up being returned to the heart, so the heart muscle tissue is able to stretch to fill with more blood, and thus can contract harder. The heart
The main problems with artificial hearts is regulation of blood pressure and cardiac output based on the needs of the person.
There are only two artificial hearts that are FDA approved.
The SynCardia temporary Total Artificial Heart, which is temporary until a replacement heart can be found.
And the AbioCor Replacement Heart. The person that lived the longest with this device only lived a little more than a year.
There are a few prototypes that are being developed, and we will definitely be seeing some better artificial hearts in the near future.
Here is an article about one such prototype: _URL_0_ | [
"Cardiovascular-related artificial organs are implanted in cases where the heart, its valves, or another part of the circulatory system is in disorder. The artificial heart is typically used to bridge the time to heart transplantation, or to permanently replace the heart in case heart transplantation is impossible.... |
How do glow sticks work? | The glow stick has two main components: a mixture of diphenyl oxalate and various dyes, and a small glass tube filled with hydrogen peroxide. By bending the stick, you break the glass, releasing the hydrogen peroxide. The H2O2 decomposes the diphenyl oxalate, producing 2 phenyl groups and a molecule of peroxyacid ester. The ester then reacts with the dye, which produces carbon dioxide, while exciting the dye to a higher energy level. This energy is released as a photon (light), the color of which depends on what dye is used.
[Wikipedia](_URL_0_) has a more thorough explanation. | [
"A glow stick is a self-contained, short-term light-source. It consists of a translucent plastic tube containing isolated substances that, when combined, make light through chemiluminescence, so it does not require an external energy source. The light cannot be turned off and can only be used once. Glow sticks are ... |
what is being woke and what does it mean to be woke? | Being "woke" is slang these days for being "awakened to the truth" so to speak. In lamens terms, being aware of global issues that are usually ignored by the ignorant.
Veganism, global crises, conservation, the meat trade, government conspiracies etc are all things that "woke" people stereotypically are concerned about, as opposed to the average population that go on living their daily lives blissfully ignorant.
Woke people tend to do research and look deeper into things that enlightens them to these topics | [
"\"The Waking\" is a poem written by Theodore Roethke in 1953 in the form of a villanelle. It is a self-reflexive poem that describes waking up from sleep. It comments on the unknowable with a contemplative tone. It also has been interpreted as comparing life to waking and death to sleeping.\n",
"Early morning aw... |
Why is the Earth's freshwater supply diminishing? | > it goes to the sewage cleaning facility, and then back to our water taps.
This isn't quite right, most of our treated sewage does not get sent back to the water supply as it's not fit for drinking and we either drain it into the ocean or use it for irrigation and other non-drinking uses. Most of our drinking water is from rivers, glaciers, wells/springs, rain, etc. When there are droughts, we get less water back into our drinking water sources. | [
"Another popular opinion is that the amount of available freshwater is decreasing because of climate change. Climate change has caused receding glaciers, reduced stream and river flow, and shrinking lakes and ponds. Many aquifers have been over-pumped and are not recharging quickly. Although the total fresh water s... |
whats the difference between honey and syrup? | Honey is made by bees. Syrup is (at heart) made by plants -- though cooks process the heck out of it before we put it on pancakes. | [
"Honey syrup is a syrup made by combining honey and water and heating until the sugar dissolves. In the case of honey simple syrup, a 1:1 ratio is used. This is similar to the process for making simple syrup with sugar, and the honey syrup can be used in place of simple syrup in many cocktails, such as the Bee's Kn... |
How do PET scans work? Confused between gamma emitters vs positron emitters. | Emitting a positron and emitting a gamma ray are two totally different kinds of nuclear decays.
As the P in PET implies, it’s very important that a positron emitter is used, and not just any gamma emitter.
That’s because the emitted positron comes to rest somewhere near the place where the decay occurred, and then annihilates with an electron. The annihilation produces two gamma rays of equal energies, **emitted back-to-back**.
Detecting **both** of these correlated gamma rays is what allows you to backtrack their position of origin.
Gamma radiation is highly penetrative, so it’s not hard for a 511 keV gamma ray to exit your body without interacting with it. Of course some gamma rays will deposit energy into your body, and the patient will receive some dose of radiation due to the gammas (in addition of whatever radiation is emitted in the beta decay). But despite that, PET scans can be very useful. | [
"Positron emission tomography (PET) scanning deals with positrons instead of gamma rays detected by gamma cameras. The positrons annihilate to produce two opposite traveling gamma rays to be detected coincidentally, thus improving resolution. In PET scanning, a radioactive, biologically active substance, most often... |
What are historically the most peaceful countries? | Mostly countries who have a lack of natural resources that other countries desire. This includes countries like iceland or as you said new zealand. But there is also the factor that these countries(like the ones listed above) were protected by powerful empires.
There is also the factor that these countries may be in a very defendable region like switzerland.
To answer your question simply.
Portugal
Armenia(kind of)
Switzerland
Sweden
Norway
There are many others I could list but this is a complicated question.
| [
"The Washington Times: \"U.S. Ranked the 114th Most Peaceful Nation on Earth says Annual Global Ranking:\" “The index is produced by the Australia-based Institute for Economics and Peace, which figures that the impact of strife worldwide is $14.3 trillion. News is not all bad, though. In a nutshell, the index found... |
how does the finance industry benefit society? | Depends which part you are talking about. You can get a financial advisor which will help you manage your assets and set you up so you can retire. You can deal with people that forecast costs a business will have to spend so you can plan for it. You can buy stocks and bonds which help 1 party get money for a large project and the other party can earn interest.
Finance basically deals with anything related to money and helping manage those. Managing money is a benefit to society because it let's people be more efficient with what they have. | [
"Today, there are four parts of the economy: Business, Household, Public, and Non-profit. Typically, we only think that the business sector creates any wealth, and that the other three serve the business sector and alongside it. The truth is that all four parts of the economy generate wealth, and that wealth flows ... |
how does a company go about separating, like with activision blizzard? | I can’t say In activisions case. But my old company simply bought themselves a majority share. This means the company took all of their profits and bought back their own stock. In my old companies case it took around 10 years to complete but with enough capital a company could do it overnight. | [
"Kotick proposed the merger to Activision's board, which agreed to it in December 2007. The new company was to be named Activision Blizzard, and would retain its central headquarters in California. Bobby Kotick of Activision was announced as the new president and CEO, while René Penisson of Vivendi was appointed ch... |
If the Earth was a smooth, frictionless object (still spinning and revolving around the sun) and if I were to set an equally smooth ball rolling, would it circle the Earth forever? | If it were truly frictionless, you wouldn't even need to roll it. Gravity would keep it on the surface, but it would't spin along with the Earth. It would move forever at whatever speed you initially gave it relative to the surface. If you set it down without giving it a push, it would just stay at that point and the surface would rotate beneath it (and your day would be 365 earth days, as the earth went around the sun). | [
"Riccioli also argued that the rotation of the Earth should reveal itself in the flight of artillery projectiles, because on a rotating Earth the ground moves at different speeds at different latitudes. He wrote that If a ball is fired along a Meridian toward the pole (rather than toward the East or West), diurnal ... |
why would a company spend money making offices in a leased spaced. doesn't the landlord "own" and benefit from all of the enhancements? | There are two basic issues here. First, the benefits and drawbacks of owning vs leasing and second the issue of "improvements" as you put it.
The pros and cons of buying vs renting/leasing are well understood and have to be decided on a case-by-case basis. Generally leasing is better for cash flow because you can pay month-to-month instead of needing to put down a large down payment up front. Also, with a lease, you aren't tied to the same physical location forever. If you need more space you can easily move without having to find a buyer for your current space.
As to improvements, I think you have a misunderstanding here. When a company comes in to an empty space and builds rooms, offices, shared spaces, etc. they are doing it to their specific requirements. The next company to use that space would likely have a different set of requirements and so would want a different arrangement of the space. They usually have to tear out what had been built before and redo it. So, in that case, they aren't really "improving" the space because it's actually more valuable empty than being pre-built. | [
"Companies offering serviced offices are generally able to offer more flexible rental terms, as opposed to a conventional leased office which may require furnishing, equipment, and more restrictive leases. Space is normally flexible, allowing for additional space to be allocated at short notice, should the size of ... |
why do conspiracy theorists care if drones patrol our cities? | Do you care if the police install cameras in your house, your bedroom, your toilet, or your shower? Why? Unless you're committing a crime who cares?
The idea is that people like having privacy even if it isn't to commit a crime. I don't think you're a conspiracy theorist if you'd like to have some degree of privacy. | [
"In February 2013, a spokesman for the Los Angeles Police Department explained that these drones would initially be deployed in large public gatherings, including major protests. Over time, tiny drones would be used to fly inside buildings to track down suspects and assist in investigations. According to \"The Los ... |
why does every text to speech synthetic voice pretty much suck? | We've been trying to get computers to understand natural languages for 50 years. We still haven't succeeded at that. And until we get that, we're not going to be able to get the cadence right. There's a ton of research in this area- companies like Google and Microsoft are throwing tons of money at it in addition to non-profits and government organizations funding basic research, and some of the greatest minds alive are working to figure it out. They're made a ton of progress in recent years, but it's still not enough.
The problem is that human languages don't make sense. English grammar can't be defined by a clear set of rules and there are too many exceptions in spelling and pronunciation. | [
"A study in the journal \"Speech Communication\" by Amy Drahota and colleagues at the University of Portsmouth, UK, reported that listeners to voice recordings could determine, at better than chance levels, whether or not the speaker was smiling. It was suggested that identification of the vocal features that signa... |
For other planets, how do scientist determine which pole is the North one? | _URL_0_
Relevant quotes:
Planets:
> The International Astronomical Union (IAU) defines the geographic north pole of a planet or any of its satellites in the solar system as the planetary pole that is in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's North pole.
Minor bodies:
> In 2009 the responsible IAU Working Group decided to define the poles of dwarf planets, minor planets, their satellites, and comets according to the right-hand rule.[1] To avoid confusion with the "north" and "south" definitions relative to the invariable plane, "positive" is the pole toward which the thumb points when the fingers are curled in its direction of rotation ("negative" for the opposite pole). This change was needed because the poles of some asteroids and comets precess rapidly enough for their north and south poles to swap within a few decades using the invariable plane definition.
Magnetic poles:
> Planetary magnetic poles are defined analogously to the Earth's magnetic poles: they are the locations on the planet's surface at which the planet's magnetic field lines are vertical. The direction of the field determines whether the pole is a magnetic north or south pole, exactly as on Earth.
For synchronous satellites, you define 4 more poles:
> In the particular (but frequent) case of synchronous satellites, four more poles can be defined. They are the near, far, leading, and trailing poles. Take Io for example; this moon of Jupiter rotates synchronously, so its orientation with respect to Jupiter stays constant. There will be a single, unmoving point of its surface where Jupiter is at the zenith, exactly overhead — this is the near pole, also called the sub- or pro-Jovian point. At the antipode of this point is the far pole, where Jupiter lies at the nadir; it is also called the anti-Jovian point. There will also be a single unmoving point which is furthest along Io's orbit (best defined as the point most removed from the plane formed by the north-south and near-far axes, on the leading side) —this is the leading pole. At its antipode lies the trailing pole. Io can thus be divided into north and south hemispheres, into pro- and anti-Jovian hemispheres, and into leading and trailing hemispheres. Note that these poles are mean poles because the points are not, strictly speaking, unmoving: there is continuous libration about the mean orientation, because Io's orbit is slightly eccentric and the gravity of the other moons disturbs it regularly. | [
"The International Astronomical Union (IAU) defines the geographic north pole of a planet or any of its satellites in the Solar System as the planetary pole that is in the same celestial hemisphere, relative to the invariable plane of the Solar System, as Earth's north pole. This definition is independent of the ob... |
How large would the universe be if there was no empty space between protons, neutrons, and electrons? | In the primordial, young, small, hot universe, there weren't protons and neutrons at all. Nucleosysnthesis didn't occur until there was enough space to have them around. So the question is sort of ill posed. Expect varying answers. | [
"Carl Sagan pointed out that the total number of elementary particles in the universe is around 10 (the Eddington number) and that if the whole universe were packed with neutrons so that there would be no empty space anywhere, there would be around 10. He also noted the similarity of the second calculation to that ... |
Is it true that baths and personal hygiene were considered dangerous for your health during the 16th/17th century in Europe? | In the mid-1480s, Nuremberg printer Hans Folz published a guide to the various public hot springs and baths he had encountered in his travels, stretching from Germany to the border of Spain. In rhyming verse, so people would remember. In 1638, on the other hand, Francis Bacon advised that it was better for one's health to bathe in the blood of infants than to drink blood out of a young man's arm, but people (except kings, in rumor) tended to object to this, so how about just placing something cold on your chest. While we should not be taking the thoughts of a man named Bacon on the myriad health benefits of animal fat as reflecting common practice, his *Historia vitae et mortis* helps set the terms for the shift in hygiene practices as reflecting changing and solidifying ideas about health and longevity.
In the later Middle Ages, bathing and cleanliness hovered somewhere between an ideal and a practice for most people. Literature and art reveal a premium on clean hands and clean babies, and religious advice literature often warns its readers away from the ancient ascetic practice of never bathing. On the other hand, English tax records suggest that a substantial portion of the urban poor didn't really have much in the way of changes of clothing, which might explain why friars complained about the stench during church services.
The noteworthy development in hygiene-health over the later Middle Ages, which as we will see may have had something to do with the 16C changes, was the revival of the (not entirely abandoned) Roman public bathing tradition. For the most part, we are talking about either natural hot springs or constructed steam baths, definitely public, and--crucial--*typically co-ed*. While theologians like Hildegard of Bingen commented that hot springs were heated by the fires of purgatory and were good for spiritual as well as physical health, it is clear that going to the baths was a euphemism for a fun day on the town. Yes, this is going exactly where you think it is.
By 1500, public baths were developing A Reputation as hot zones of debauchery, especially prostitution, and this was not a good thing. This development had something to do with bathing activities themselves and something to do with changing societal standards. The late 15th-16th century is often painted by scholars as the rise of "social discipline," a concern for outward societal order, propriety, and morality. One of the most visible displays of this is in attitudes towards prostitution. While many medieval cities operated legal brothels as a sort of "men are gonna do it anyway; might as well protect the virtuous women by discarding others" attitude, sixteenth-century councillors and churchmen were intent on stamping out the immorality altogether. I stress that this was a slow change, occurring at different times in different places (you can find some public baths operating in Germany on the eve of the Thirty Years War, and Scandinavia clung even more tenaciously to the practice).
So the first change in the decline of bathing over the sixteenth century relates to public baths and a recalibration of "public morality." One factor that may or may not be related, given the association between public baths and sex, is the spread of syphilis. From the 1490s on, European writers paid A LOT of attention to the French/foreign disease (although, since some of the writers had syphilis themselves, they often sought to emphasize its claimed non-sexual patterns of transmission. Which was definitely how all of them picked it up, definitely). Surely the fear of it was greater than the reality, but that could have provided yet more impetus for leery town councils to close their brothels and baths.
The third factor, and what we see flourishing in Bacon's writing (there are plenty of other examples; he's just my favorite in basically all things) is the popularization of knowledge (or "knowledge," if you prefer) about health. This is certainly growing over the late Middle Ages, with a small but increasing number of medical treatises published in the vernacular and a proliferating variety of medical practitioners forming guilds in cities. The eventual triumph of the print industry and the vernacular, though, *really* helps spread not just lists of remedies but the underlying theories to more and more people.
What Bacon describes, in particular, is the belief that the body can be nourished but also lose nourishment through the skin, not just eating. The goal of bathing, to him, was to keep the good from leaving while still letting in other good things. Montaigne, old school, longed for the days when steam and hot water baths opened up people's pores. Bacon wanted those *sealed off*. He wasn't opposed to bathing, just, the water had to be cold, and it had to be quick. And hey, why use water at all if you could get the same benefits from a cold solid pressed against your skin? *Vitae et mortis* has a whole excursus on the proper method of "anointing" oneself before and after the quick dip in cold water, which basically consists of mixing liquid oils with various herbs and spreading it all over your skin. (My forehead is breaking out in sympathy zits.)
What *did* concern people was cleanliness of clothes and cleanliness of blankets--and smell. Elisabeth-Charlotte von der Pfalz, Liselotte to her friends and Duchesse d'Orleans at the court of the Sun King, had *everything in the world* to say about the way people smelled, and how they tried to combat it with perfumes, pomades, and...other things:
> The first Dauphin followed his father's example and took unto himself a miserable and smelly creature who was a lady-in-waiting to the old Princesse de Conti...She looked like a pug dog, and was small, with short legs, a round face, a turned-up nose, and a large mouth, filled with rotten teeth, which smelled so badly that one could smell them from the other side of the room...I believe the Dauphin took to tobacco in order not to smell the odor of her teeth.
~~
ETA: I just realized I name-dropped three of my five favorite old authors, and my username adds the fourth, so to make the circle complete:
> For this was on Saint Valentines day
> When every brid [bird] cometh there to chese his make
> Of every kinde that men thinke may...
> This noble empresse [the goddess *Natura*], ful of grace
> Bad every fowl to take his owene place
> As they were wont alway, from yeer to yere
> Saint Valentines Day, to stonden there. ([modernized here](_URL_0_)) | [
"In the seventeenth and eighteenth centuries in Europe began the Enlightenment. Philosophers developed new ideas about nature and doctors noticed the connection between lack of hygiene and disease, and the correlation of health with a good personal hygiene. Large public baths were revived in the nineteenth century.... |
why does thinking about our subconscious actions make them manual? | It doesn't. Your breathing isn't manual. You're just aware of it. Being aware of your breathing does not put you in imminent danger of asphyxiation.
People who buy into this myth are expecting their breathing to become manual, so they hold their breath and then choose to stop holding their breath...et voila. | [
"Behaviorism notwithstanding, the unconscious mind has maintained its importance in psychology. Cognitive psychologists have used a \"filter\" model of attention, according to which much information processing takes place below the threshold of consciousness, and only certain processes, limited by nature and by sim... |
how come my dog can sleep in crazy positions and not hurt her neck but if i sleep just slightly off my pillow or at an odd position my neck hurts all day. | Partially because we evolved to walk upright, that changed the way our spine works in relation to quadrupeds, and means we have a lot less flexibility in our neck than they do. The movement of our head is severely restricted, for this reason our neck muscles are a lot less powerful and developed than those of dogs. The other reason is exercise, dogs are insanely flexible and are constantly bending their bodies in crazy ways. The average modern human just walks upright or sits upright most of the day.
I have 2 labs, male is 3 years old, female is 90 days old. The big guy uses the little girl as a pillow, and she doesn't even mind. She sleeps under the weight of the head of a 60kg dog, no problems. Sometimes she sleeps with her head hanging from the couch. | [
"A dog may form a strong attachment to the crate eventually, feeling comfort and safety, after the initial feeling of distress and vulnerability. This behavioral effect has been compared to Stockholm syndrome. Dogs that are trained to sleep in a crate, when allowed to sleep in a bedroom, can show signs consistent w... |
Have there ever been any conflicts between the Republic of Congo and DRC over who gets the name "Congo? | Supplementary question - what was the origin of the name "Zaire" and why was it dropped in favour of the current (confusing) DRC? | [
"The Republic of the Congo () was a sovereign state in Central Africa that was created with the independence of the Belgian Congo in 1960. From 1960 to 1966, the country was often known as \"Congo-Léopoldville\" (after its capital) in order to distinguish it from its north-western neighbour, also called the Republi... |
why do "million" and "millennia" sound the same, but one refers to millions and the other refers to thousands? | Both derive from the word 'mille', thousand. But million refers to thousand thousands, whereas millennia refers to thousand years, or 'mille anni'. | [
"The million is sometimes used in the English language as a metaphor for a very large number, as in \"Not in a million years\" and \"You're one in a million\", or a hyperbole, as in \"I've walked a million miles\" and \"You've asked the million-dollar question\".\n",
"1000 or one thousand is the natural number fo... |
The spread of Confucianism to Japan and Korea | The last Korean Dynasty, Joseon, was found upon the idea of Neo-Confucianism which was born during Southern Song Dynasty China.
The previous Korean Dynasty, Goryo, adopted primarily Buddhism as its main belief system. However, Near the end of Goryo dynasty, Buddhism has become corrupt. Monks controlled huge amount of lands as people excessively gave away their land, partly due to gain entry into "heaven", while others were forced by powerful temples. It eventually destroys Goryo's economy as people volunteered to work at the temple/become monks as it was decent method of living. Number of people who actually produced goods began to decrease, causing havoc.
A New dynasty, Joseon, was born out of this, (1392) lead by Neo-Confucianism scholars. It was a much more progressive belief system at the time. Where Buddhism focused on enlightenment and afterlife, Confucianism focused on human nature and their current lives, and disregarded any Buddhist belief of afterlife and enlightenment. It was followed by land reform and a encouragement towards agriculture based economy.
Founding of the new dynasty under new ideals quickly entered sort of a "golden age" for Korea, (King Sejong is still a revered figure during this time) and Neo-Confucianism was deeply rooted by the 15th century as all the intellectuals in Korea has adopted it by then. (There is a struggle between old elites and Neo-scholars throughout the initial half of Joseon period, but that's whole another post)
[source on King Sejong era Confucianism](_URL_0_)
Confucianism did not take as much of a deep root as it did in Korea in Japan. Buddhism has always been at full force in Japan since its introduction in 6th century. Also Japan has its own native belief called Shinto. While Japan has adopted many of philosophies of Confucianism in the system of government (As it was adopted by the "superior" Chinese Dynasties at the time), Buddhism remains strong. Many early Confucianism scholars in Japan are actually Buddhist monks. This is a huge contrast to Korea/China where Buddhism declines as Confucianism rose.
Part of problem with Confucianism in Japan (especially after rise of Samurais and Shogunate) is that Confucianism demands loyalty. Japan in history often times have multiple rulers representing the country; Emperor acting as symbolic figure, another ruler with real power (Shogun or Regency of some form) actually rules the country. This creates confusion when demanding loyalty; who should you be loyal to?
However, Neo-Confucianism does take some foothold in Japan after their invasion of Korea in 16th century. As the emperor by this time has been completely relegated to symbolic figure and all but forgotten, Shogunate was the effective ruler of Japan. But it never really settled as "main-stream" belief as it does in same period Joseon or Ming dynasty. Zen Buddhism remains a strong belief in Japan along side Neo-Confucianism.
[source on Confucianism in Japan](_URL_1_) | [
"Buddhism and Confucianism were later introduced to Korea through cultural exchanges with Chinese dynasties. Buddhism was the official religion of the Goryeo dynasty, and many privileges were given to Buddhist monks during this period. However, the Joseon period saw the suppression of Buddhism, where Buddhist monks... |
why can't we put a metallic grille on plane reactors to keep birds from getting to the engine? | We can’t do this because if a bird we’re to hit the grille and damage it, it could cause more damage as the grille will become entangled in the engine.
Most engines only take ~20% of air through the core of the engine, everything else is bypassed and creates thrust | [
"The use of transformer coupled stubs also provides improved protection for 1553 terminals against lightning strikes. Isolation is even more critical in new composite aircraft where the skin of the aircraft no longer provides an inherent Faraday shield as was the case with aluminum skinned aircraft.\n",
"The NTSB... |
Do we know exactly how strong the Olympians of ancient Greece were compared to the Olympians of today? | Keep in mind that the Olympics was a ritual rather than a purely athletic event. Ancient Greeks did not generally record the distances, weights, or times of the races and competitors. All that mattered was beating everyone else - lifting more than all the previous people, finishing this race first. Doing better than people did four years ago was also not important.
One of the few actual recorded results is Phayllos of Kroton's long jump. The long jump sand pit was 50 feet, and he jumped clear across it, some 50 plus feet. Considering the current record is still under 30 feet, this calls into question the accuracy of the recording, whether this is exaggeration and myth, or if it was a multi-jump event. We just don't know.
I think you could safely speculate that Olympians are stronger today than they were in ancient Greek times due to training, nutrition, and dedication to events that just wasn't available at the time. | [
"In ancient Greek religion and mythology, the twelve Olympians are the major deities of the Greek pantheon, commonly considered to be Zeus, Hera, Poseidon, Demeter, Athena, Apollo, Artemis, Ares, Aphrodite, Hephaestus, Hermes, and either Hestia or Dionysus. They were called \"Olympians\" because, according to tradi... |
Was the M4 Sherman a good or bad tank? | So as /u/XenophonTheAthenian said, judging a tank simply on how readily it might burn when knocked out is a pretty narrow metric with which to measure the effectiveness of a tank, and by that metric the Sherman doesn't actually do that poorly. Xenophon already mentioned the problem wasn't unique to the Sherman at all but I figured I would back that up with some actual data, and then I wanted to add some *actual* context to what the Sherman actually was and what it wasn't because I have a feeling that your friend wont simply be convinced just by learning that the Sherman didn't catch fire any more than any other tank did (and less often than some other famous tanks).
So how often the Sherman was considered to burn really depended on the circumstances in which the data was collected. An American study conducted in France for instance found that 65% of Shermans burned when they were knocked out.^1 While a study of the British 8th and 24th Armor Brigades found that about 56% of there tanks burned when knocked out.^1 Another study found that they burned about 80% of the time. These rates all really depended on the sample of course so you are never going to get a single definitive rate.
The causes of this was primarily the storage of ammunition. In the early version of the Sherman, which I will refer to as "small-hatch" Shermans from now on, all of the ammunition was either stored in the turret (the ready-rack) or in the ammunition racks in the [sponsons](_URL_7_) over the tracks. The problem with that location is that most of the time when tanks were knocked out, it was from hits to the sides which meant that the ammunition racks were quite often directly in the line of fire!
Even so, the Sherman was by no means the only offender in this regard. The Panther stored its ammunition in [literally the same location](_URL_10_), so did the [Panzer IV](_URL_13_), and the [Tiger](_URL_14_). This meant that any time these tanks were hit from the side they were very likely to burn. And according to an allied study the Panzer IV was the worst, burning more than 80% of the time.
The American's however recognized this as an issue with the Sherman and quickly set about attempting to fix the issue.
The first thing the US did was to issue an armor applique kit which would be applied in tank depots before being issued to troops in the field. There were four different kits but the one I am referring to can be seen in [this picture](_URL_11_). Each of those armor plates were intended to simply increase the thickness of the hull armor over the ammo racks. Eventually the applique armor, on M4A1s at least, was made part of the actual [hull casting](_URL_0_), but on tanks like the M4, M4A2, M4A3, and M4A4 the applique armor was simply welded on till the production of those tanks ceased.
The applique armor was never seen as the final solution however, and in December 1943 the second generation of Sherman's, or large-hatch Shermans, began rolling off the production lines. This new generation of Shermans included a number of improvements but perhaps the most obvious change was the the front of the hull which can be seen in this picture of a [small-hatch](_URL_12_) and [large-hatch](_URL_8_) M4A3. The important thing to note however is that on the large hatch Sherman there is no applique armor plates.
This was one of the major improvements of the large-hatch Shermans, at least as far as fires go anyway. According to studies conducted by the Ordnance Department the best place for the ammunition was on the floor of the tank, and in some reports they specifically refer to this arrangement as the "Soviet manner", because this was how ammunition was stored in the T-34. So all the ammunition was moved to the floor in armored containers, and the turret basket was removed to allow access to the containers. Another feature that was added was called Wet Storage.
Wet Storage was basically this: all the ammunition boxes which were in the floor were surrounded by a water jacket. The idea was that if the ammunition racks were hit they would be flooded with water and put out any fire. On 75mm armed Shermans the water jacket could hold 38.1 gallons or .366 gallons per round (104 rounds total) and in 76mm armed Shermans 34.5 gallons or .515 gallons per round (71 rounds total).^2
Wet Storage worked extremely well, Shermans equipped with it now burned between 10 - 15% of the time as opposed to the 55 - to 80%^3 of the time, making the Sherman by far the safest tank on the battlefield as far as fires went anyway.
Another thing your friend will probably mention is the Sherman's gas engine, and he will probably cite this as a source of the fires in the Sherman. If he does this, you should point out that *all* German tanks also had gas engines, and ask why didn't their tanks have the same reputations. (Though they really ought to have anyway, they caught on fire just as often).
Now as for the *context* as the first comment here put it. Now I could go on and on but I figure a good way to give you sort of the readers digest version is by addressing most the points I mentioned in [this](_URL_3_) post. So lets do each one in order.
1. American tanks weren't designed to fight other tanks./The Sherman was particularly likely to burn or easy to destroy.
This simply isn't true, and when the evidence is examined you will see that US forces did quite well. In a study of 87 tank engagements involving involving the 3rd and 4th Armored Divisions the US actually destroyed more enemy tanks and equipment then they lost, and in these engagements they were quite often fighting Panthers.^4
In the first 3 examples in the study, which involved a total of 27 engagements, a total of 155 M4s faced off against 114 Panthers. The US lost 10 M4s while the Germans lost 70 Panthers^4.
And the Sherman had been designed from the get go to fight other tanks. In [FM 17-10](_URL_6_) it states explicitly that both medium and light tanks should be used to fight other tanks. In 1942 the Sherman was more than capable of taking on any tank on the battlefield. Its 75mm gun could kill any German tank at the time and with 90mm of armor on the front of the hull (effective) it was mostly impervious to any German tank except at close range.
This situation remained about the same until mid 44, yes the Panzer 4 was upgunned, but even the 7.5cm KwK L/48 couldnt penetrate the front of the Sherman beyond 1100 meters while the Panzer IV remained vulnerable from about the same distance.
The Panther did outclass the Sherman, there is no doubt of that, and unlike what that other poster said it even outclassed the late war Sherman, but the Panther had its own issues, and while it did outclass the Sherman one on one, it was not so superior that it couldn't be overcome as the study I mentioned showed.
_URL_1_ took X number of Shermans to kill Panzer IV/V/VI
This is a very silly claim and there is no basis for it. Keep in mind that the Germans lost more tanks to the US than the US lost to the Germans.
Really, the Sherman was a tank that was comparable to other medium tanks of the era, for instance the T-34. Both tanks were armed and armored in similar ways, and they both served about the same roles in their respective armies. Neither tank was perfect, but they were good enough to do the job that was expected of them and they did them well.
Anyway, I feel that the second part wasn't all the eloquent but I am way past my bed time. If there was anything I did not explain well, let me know and I will clarify, I admit I was sort of pulled in all directions wile trying to put this together.
Oh by the way, the Ronson nickname is almost certainly anachronistic. The "lights first time, every time" was a slogan that didn't come out until the 50s. Ronson did make flamethrowers for Shermans though and I think that is probably where the name came from.
List of sources:
1. John Buckley, [British Armour in the Normandy Campaign]( _URL_2_)
2. R.P. Hunnicutt, [Sherman: A History of the American Medium Tank](_URL_4_)
3. Steven Zaloga, [Armored Thunderbolt: The U.S. Army Sherman in World War II](_URL_5_)
4. David Hardison, [Data on Tank Engagements involving the 3rd and 4th Armored Divisions](_URL_9_)
| [
"The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the United States and Western Allies in World War II. The M4 Sherman proved to be reliable, relatively cheap to produce, and available in great numbers. Thousands were distributed through the Lend-Lease program to the British Commo... |
why are the trees still standing with green when the homes are charred? _url_0_ | The level of moisture in living trees is much greater than that of lumber and other building materials. | [
"The leaves are yellowish green, and during extensively dry and hot periods the tree will shed them. It has the characteristic of performing photosynthesis in its bark (hence the green color), and this is what allows it to survive leafless in hotter periods.\n",
"Because the eastern white pine tree is somewhat re... |
if cameras can take videos with fps equaling single shutter speeds, why do photographers take dedicated still shots instead of video recording everything and later just isolating single frames for “photographs?” | In some cases you can, but when you take a single frame you have more control over the light. When you take a photo you can balance the depth of field, aperture size and iso- getting the right ratio of the three can give you much needed control in certain scenarios. When you record video- most of those settings become automatic so a lot of work might be needed in post production to get the shot you need.
I’m sure with more expensive technology you can do it easier, but basically the needs for photos and video are not the same to produce an image. | [
"Cameras capable of high continuous shooting rates are much desired when the subjects are in motion, as in sports photography, or where the opportunities are brief. Rather than anticipate the action precisely, photographers can simply start shooting from right before they believe the action will occur, giving a hig... |
Which bacteria did mitochondria come from? | you're close. [cyanobacteria are thought to have given rise to chloroplasts,](_URL_2_) not mitochondria.
But your professor is probably also wrong. It's still controversial, but [mitochondria are thought to have come from something like Rickettsia](_URL_0_), maybe (s)he meant [alphaproteobacteria?](_URL_1_) | [
"Biologists had long suspected that mitochondria originated from bacteria that had been incorporated as endosymbionts (\"living together inside\") of larger eukaryotic cells. It was Lynn Margulis who from 1967 on championed this theory, which has since become widely accepted. The most convincing evidence for this t... |
Why does buoyancy equal the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g and not the density of the object submerged? | > why does buoyancy have to do with the weight of displaced fluid rather than the weight of the object submerged?
The weight of the object is the irrelevant to the buoyant force. The water doesn't "know" what the weight of the object is, it just exerts a pressure on it. The total force (which is a sum of all the pressure on the object) is the same for any objects of equal size. A ball of lead will experience the same force on it as a balloon of the same size.
> since the sum of the vertical forces that are applied in an object, in equilibrium, submerged in a fluid equals the weight of that object. Which also gives buoyancy...
No. The *buoyant force* is *only* the force by the fluid on the submerged object. The *net* sum of the forces (buoyant force pushing up + the weight of the object pointing down) tells you the *motion* of the object -- a lead sphere in water will sink because it is heavier than the water, but an air bubble of the same size will rise because it is lighter than the water, but *they both have the same buoyant force on them.* | [
"The weight of the displaced fluid is directly proportional to the volume of the displaced fluid (if the surrounding fluid is of uniform density). In simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multi... |
how do large companies send bulk letters? | I worked at a company where I spent one whole week with just printing letters (I had data from excel worksheet), putting them into envelopes and then bringing them to post office. I had to take one colegue with me, because every day, it was like 60 kilograms of envelopes.
So it’s mostly repetitive boring work someone has to do for slave-grade paycheck. | [
"Bulk mail is mail that is prepared for bulk mailing, often by presorting, and processing at reduced rates. It is often used in direct marketing and other advertising mail, although it has other uses as well. The senders of these messages sometimes purchase lists of addresses (which are sometimes targeted towards c... |
how does the sit in that is going on in the house of representatives work? | The House is in recess right now (could be wrong though) so the representatives there are basically sitting in protest and to draw attention to their cause. The House can go ahead and try to put a bill to vote or they could convene in another location if the Speak of the House decides to. That is in the procedural rules I believe | [
"Like the Senate, the House of Representatives meets in the United States Capitol in Washington, D.C. At one end of the chamber of the House is a rostrum from which the speaker, Speaker pro tempore, or (when in the Committee of the Whole) the chair presides. The lower tier of the rostrum is used by clerks and other... |
how do polygraphs work. | They detect abnormal changes in heartbeat, blood pressure, etc. They prime these machines by asking you simple questions (like, "what is your name?") to see how you react when telling the truth. Theoretically there should be physical results when you lie that you have no control over. Problem is that some people may just get nervous when asked certain questions even if they aren't lying. I guess don't feel anything when answering a polygraph? If you don't have an emotional reaction it wouldn't detect any abnormal changes in your heart beat etc. | [
"In mathematics, and particularly in category theory, a polygraph is a generalisation of a directed graph. It is also known as a computad. They were introduced as \"polygraphs\" by Albert Burroni and as \"computads\" by Ross Street.\n",
"In document duplication (as opposed to law enforcement and such), a Polygrap... |
Did the Romans have any racial prejudices that they held, particularly when they conquered other lands with people of darker skin tones? Did this factor into who was or wasn't sold into slavery? | Hi, hopefully someone can drop by with an answer particularly wrt slavery, but meanwhile, you may be interested in a few earlier discussions
* FAQ section [Pre-History of "Race" and Racism](_URL_5_), particularly the following
* [Racism in the ancient world?](_URL_0_) featuring /u/einhverfr
* [How would I be treated in Ancient Roman as a black man?](_URL_4_) featuring /u/Tiako
* [Is it possible that pope Victor the first was black?](_URL_1_)
* [Did the Greeks and Romans hold any racist views towards their neighbors?](_URL_2_)
* [How racist was the Roman Empire?](_URL_3_)
| [
"Roman slavery was not based on ideas of race. Slaves were drawn from all over Europe and the Mediterranean, including Gaul, Hispania, North Africa, Syria, Germany, Britannia, the Balkans, Greece, etc. Those from outside of Europe were predominantly of Greek descent, while the Jewish ones never fully assimilated in... |
what are eyeballs doing when looking at autostereograms (magic eyes) and why can some people not see the hidden image? | Typically, your vision is diverging, although some stereograms are designed with a cross-eyed view.
You are basically tricking your brain into thinking you are looking at something three-dimensional.
When you diverge your eyes, you are focusing them at a point *behind* the paper. Normally, this results in whatever picture you are looking at to simply be distorted and look like nothing (you would see a double-image of the picture overlapping itself) except that stereograms are specifically made so that when both of your eyes are focusing at a point behind the picture, the two double-images overlap in such a way to trick your brain. The differences between what your left eye and your right eye are used by your brain to interpret depth, since usually that's what happens when you look at some three-dimensional shape. Try looking at something three dimensional and repeatedly closing your eyes and opening just one eye and then just the other; you will notice you see two slightly different things. Stereographic images create the illusion of depth due to having each eye see something slightly different, but in such a way that the image can be interpreted as three-dimensional instead of just two overlapping images with no depth, which is what you would see if you tried the same with an ordinary painting, for instance - even though your eyes see two different images, the images are just *too* different, and your brain instead interprets that as your eyes focusing improperly which just gets you to look at it normally.
Some people have trouble relaxing their eyes enough to look through the picture in the first place, and others have difficulty maintaining the illusion due to their brains having a tendency to snap them back to the more "normal" way of looking at the image, but I don't think there are any people who are actually incapable of ever seeing such images.
| [
"Magic Eye is a series of books published by N.E. Thing Enterprises (renamed in 1996 to Magic Eye Inc.). The books feature autostereograms, which allow some people to see 3D images by focusing on 2D patterns. The viewer must diverge their eyes in order to see a hidden three-dimensional image within the pattern. A \... |
How was the Republic of China able to fight off the Japanese between 1937-1945, while also fighting against the Communist Party 1927-1950, and being split between warlords? | Both the Communists and Warlords were a significant distraction for the Nationalists during the war against the Japanese, however the Nationalists did not fight all three at the same time.
The Nationalists actively avoided engaging with the Japanese until 1937 (the invasion of Manchuria occurred in 1931), with the intention of focusing their efforts to defeat the Communists. In 1937 a Manchurian warlord - Zhang Xueliang, "The Young Marshall" - kidnapped Nationalist leader Chiang Kaishek and forced him to enter into a truce with the Communists, and to form a united front against the Japanese.
As to the Warlords, the Warlord Period is usually considered to have ended in the late 20s after a Nationalist campaign to unite the country - the Northern Expedition. Parts of China did continue to be under the control of ostensibly allied warlords, over whom the Nationalists could exert limited influence. Quite limited actually, the Communists famously and repeatedly exploited the loose relationship between Nationalists and the Warlords to survive the Long March.
Even during the Sino-Japanese war and despite the truce, Nationalist attention seems to have been divided between the Communists and the Japanese. US General Stillwell frequently expressed frustration that the Nationalists did not appear committed to the war, and that Chiang Kaishek was more interested in preserving his forces for the renewal of hostilities with the Communists.
As to how they fought, the Nationalists were forced into a conventional war against the Japanese with inferior forces. They were unable to commit the necessary resources to resist the Japanese occupation of large cities, but were able to effectively resist over-extended Japanese forces in China's interior. The Communists in contrast fought a guerrilla war, avoiding pitched battles and occupying territory after Japanese forces had moved on. | [
"In the course of the Second World War (1939–45), the Communist Party of China (CPC) and the nationalist Kuomintang party (KMT) set aside their civil war in order to fight, defeat, and expel Imperial Japan from China. To that end, the leader of the USSR, Joseph Stalin, ordered Mao Zedong, leader of the CPC, to co-o... |
What's the status of the conclusions of the Miller-Urey experiment today? | The standing is (and I am an astrobiologist who talks about this often) that although a great experiment it was flawed from the beginning. IE the early Earth atmosphere we now know was nothing like what Urey thought. This makes the results not matter. On the other hand as mentioned by shavera it is an experiment in showing that it is possible. | [
"In July, Miller went to Washington to brief the SDI Office (SDIO) on their progress. While the instrumentation concerns had been publicly reported on multiple occasions by this point, he failed to mention these issues. Several sources noted this, and one stated they \"were furious because Miller used the old view ... |
At what point did self replicating molecules become what today is known as life? | I'm not sure I'm understand the question, since I would consider "self-replicating molecules" be a definition of "life", which would then make your question "At what point did life become life?". | [
"There are several theories about the origin of small molecules that led to life on the early Earth. They may have been carried to Earth on meteorites (see Murchison meteorite), created at deep-sea vents, or synthesized by lightning in a reducing atmosphere (see Miller–Urey experiment). There is little experimental... |
Why can't the Navier Stokes equations be solved in 3-D? | Simple explanation: this Nonlinear PDE does't have a closed form solution. We approximate in a way that is analogous to Riemann sums in integral calculus which is what is known as CFD.
The millennium prize has a good write up on why this hasn't been solved.
Trivia: A famous physicist once said that when he died he would get to heaven and ask God why quantum mechanics and why turbulence. He emphatically believed there would be an answer for the former but not the latter. | [
"The Stokes equations represent a considerable simplification of the full Navier–Stokes equations, especially in the incompressible Newtonian case. They are the leading-order simplification of the full Navier–Stokes equations, valid in the distinguished limit formula_10\n",
"The incompressible Navier–Stokes equat... |
I am 23 years old, does my body still have the atoms in it that made up the sperm and egg cell that made me? | I'm just an undergraduate chemistry student, but I would venture to say that it is very likely that you still have atoms in your body that made up the egg and sperm that you grew from. Here's why:
*Actually how many atoms were in your predecessor cells to begin with?*
There are an astounding number of atoms in your body. Like a cubic fuckton. One drop of water, if it weighs 0.05g, is around 1.67x10^21 molecules, which is 5x10^21 atoms (water is made of two hydrogen atoms and one oxygen atom), or 5x10^19 atoms per gram. The egg you came from was probably about 80% water and a human egg weighs about 10ug. If we say that an egg has roughly the same atom density as water, that translates to 5x10^14 "original" atoms (or five hundred TRILLION atoms). The sperm cell is the smallest human cell, but it would still probably add billions of atoms to the equation. Although there are no accurate figure as to how many cells there are in the human body, it is estimated to be between ten and a hundred trillion (within two orders of magnitude of the estimated atoms in your original cell). This means that, theoretically, EVERY cell in your body could have at least ONE atom from your original cell. Obviously this is a huge stretch. But the probability that at least one cell in your body now has at least one atom from conception is astronomically high.
*But how can your body maintain atoms if old cells are constantly dying and new cells are constantly forming?*
Any number of ways.
Your body (and any other organism/chemical process) thrives on efficiency. This means that life has adapted since life began to maximize its ability to recycle energy and matter that is already in the body rather than constantly getting rid of valuable molecules. Cells that die in your body are often dissolved by highly acidic lysosomes into the organic molecules that are your body's building blocks - simple carbohydrates, amino acids, nucleic acids, glycerol, salts, etc. These are, consequently, the same molecules that your body is designed to extract from the food that you eat, so many of them are reabsorbed and used for the creation of new cells. Granted this process isn't 100% efficient, and it probably isn't even close to 100%. But even if you only manage to keep 30% (arbitrary number) of your atoms each year, you will still have around 5000 atoms retained in your body after 23 years (5x10^14 /3^23).
Another one of the ways your original cell can share atoms is DNA. DNA in every single one of your cells comes from the combined DNA from your original sperm and egg cells. This happens through DNA replication. That means that your second cell has DNA made from materials in your first cell. Your third and fourth cells contain DNA made from materials in your first and second (which came from your first cell) cells.
Basically, atoms are so small and there were so many of them in your first cell that there is a very high probability that you still have some right now. This is the same reason that most scientists believe alien life is extremely likely - the universe is just so damn big that it pretty much has to exist from a probability standpoint. A popular thought experiment for physics class goes something along the lines of, "How many of the atoms that you breath in with each breath are molecules that Jesus Christ (or Julius Caesar) breathed in his lifetime?" (you can google this). The answer is something along the lines of 30 to 100 or something if I remember correctly. If you constrain a similar question to only your body, the number is going to be a LOT higher.
**TL;DR - YES!**
Edit - fixed unit error. | [
"During conception, the father's sperm cell and the mother's egg cell, each containing half the amount of DNA found in other body cells, meet and fuse to form a fertilized egg, called a zygote. The zygote contains a complete set of DNA molecules, a unique combination of DNA from both parents. This zygote divides an... |
Is developing near or far sightedness something unique to humans, or could other animals conceivably develop poor vision? | Lots of animals have bad distance vision..they tend to use other senses for sensing far away, or spend most of their time in enclosed spaces. Rhinos are notorious examples, but lots of mammals are this way.
Worth noting that human nearsightedness appears to be largely environment induced, and is uncommon in premodern societies. It's likely we just haven't fully adapted to growing up mostly indoors yet. | [
"Near-sightedness is the most common eye problem and is estimated to affect 1.5 billion people (22% of the population). Rates vary significantly in different areas of the world. Rates among adults are between 15 and 49%. Rates are similar in females and males. Among children, it affects 1% of rural Nepalese, 4% of ... |
the sounds a computer makes when downloading | Downloading data is silent. What you're likely hearing is the sound of the hard drive writing the data to disc. For old HDDs (not newer SSDs), the data is stored on magnetic platters and read/written by a read/write head at the end of an articulated arm. The movement of the arm along with the spinning of the platter allows the read/write head to access every location on the platter. Both the arm and the platter make noise when they move, but the arm is by far the noisiest, making a rapid clicking sound as it sweeps back and forth over the platter. | [
"Rather than a dedicated sound-synthesis chip, the Apple II has a toggle circuit that can only emit a click through a built-in speaker or a line out jack; all other sounds (including two-, three- and, eventually, four-voice music and playback of audio samples and speech synthesis) are generated entirely by software... |
why is there such racial tension between australian aboriginals and australians? | Australian here, the short answer is that it's complicated.
Many Aboriginal people are in lower socioeconomic groups, especially those living in regional Australia. To combat this the government offers many programs and benefits to Aboriginal Australians, which causes a degree of resentment from other Australians, however this occurs in many countries where "affirmative action" is in place.
There are some Aboriginal people who take advantage of the government programs, they tend not to work and drink heavily. This lifestyle is unfortunately often passed down to Aboriginal children. Non-Aboriginal Australians resent that their tax-dollars are going into government programs which fuel this sort of behavior. Note that while some non-Aboriginals also exploit government programs it is generally much easier to do so as an Aboriginal.
For many older Australians there is tension regarding the portrayal of historical events involving Aboriginals. For example in Australians schools children are taught about the stolen generation where Aboriginal children were forcibly removed from their families to be educated by the state. Some older Australians claim that the parents of the children who were forcibly taken belonged to unfit parents (alcoholic or homeless), and that many Aboriginal parents gave up their children. Of course the truth in the matter is lost to history, so this will remain a source of tension.
On top of this, due to the events that have occurred, many Australians find it difficult to celebrate and acknowledge the achievements of Australian colonists and pioneers without attracting criticism from Aboriginal groups. In contrast it is often required or expected to acknowledge the Aboriginal history of locations at public gatherings. Again this tension is highest in some regional centres of Australia which have rich histories from both before and after colonisation.
Ultimately the vast majority of Australians are opposed to any double standards, due to historical and socioeconomic reasons Aboriginals can attract special status more often than other minorities, which results in particular tension. | [
"Australia's large scale, Post-World War Two, multi-ethnic immigration program has seen Australia develop into one of the most ethnically diverse nations, with relatively little racial violence, and in which incitement to racial violence is a crime. Nevertheless, incidents and examples of violence between the vario... |
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