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i hang around my friend who is sick for one day and i get sick, but my dog who lives with me all the time doesn't get sick from me... why is that? | The germs that get humans sick, don't necessarily make other animals sick. That's why malaria doesn't kill mosquitos, and the avian flu was so scary. | [
"Symptoms are not necessarily distinguishable from other kinds of distress. A dog might stand uncomfortably and seem to be in extreme discomfort for no apparent reason. Other possible symptoms include firm distension of the abdomen, weakness, depression, difficulty breathing, hypersalivation, and retching without p... |
the eu election results. can't really find a broken down explanation online. | _URL_0_ for an overall result.
Eurosceptics were the first party in important nations such as UK or France, but they overall get around a fifth of the seats in the European Parliament.
Traditional, eurosupporter parties such as EEP or S & D still have over the 50% of the seats together. | [
"The European Union made it clear that they would not recognize the results of the election. All 25 member countries of the EU summoned their ambassadors from Ukraine in order to register a sharp protest against what is seen as election fraud.\n",
"Varying estimates of the elections led to a scandal. On October 1... |
How strong/muscular were ancient warriors? Did they know enough about muscle growth to be the same build as many athletes/bodybuilders now? When did humans start becoming adept at bodybuilding? | In general, the population today is much larger than they were during ancient or medieval times. Better access to food, especially rich in protein and fat has allowed the human population (at least in the western world) to become much taller.
That said, the population back then were much more accustomed to hardships and laborous work. The Athenian army that fought at Marathon marched out about 42km to fight the Persian army, donned their armour (the full equipment of the hoplite would weight about 60 kg) and charged the Persian army and forced them to retreat to their ships. Then they turned around and ran back towards Athens as they feared that the Persians were attacking the city in their absence.
It is not entirely certain if the Athenian hoplites all had heavy bronze armour, or if a majority of them were rich enough to have servants carry their equipment for them while on the march (the Spartans often had Helots do this for them), but almost none of them would have been professional soldiers, yet they had the stamina to march 42km, charge and fight the Persians and then RUN back to Athens, with all their equipment (regardless if someone else carried it for them or not).
Something that was trained a lot in ancient armies was an inverted tug of war, where two sides would form lines and try to push each other back (to be strong and coordinated enough to break the other side's line), somthing I suppose would train your strength and dexterity - and your stamina, doing that all day in the sun - a lot.
Fit is of course a relative term. A viking *Hirdman* would spend his days training, but also eating and drinking. Providing good food and drink and getting your *hirdmän* large was a matter of prestige. On campaign, food could be scarce, and having a reserve layer of fat for less bountiful days was seen as a wise precaution for soldiers, as long as they kept their strength and stamina up. A heavy soldier is also in a better position to push when the shield walls meet.
Roman gladiators were known to consume huge amounts of barley gruel in an attempt to develop a thick layer of underskin fat, which would protect the muscles and organs beneath from superficial cuts and wounds.
So, to answer your question, most soldiers from those times would be strong, have a great stamina, be very much used to harships and hard labour, but would not necessarily look fit as we define it in modern terms. | [
"The origin of strength athletics lies within prehistory. Testing each other in feats of physical prowess has been something humans have done throughout their existence. This is encapsulated in the modern Olympic motto of \"Swifter, higher, stronger\". There are records in many civilizations of feats of strength pe... |
If the heart is a muscle that needs blood to function how does it and whose blood does it pump at first? | The heart gets its blood supply from two coronary arteries, and their branches. These arteries begin immediately after the aortic valve, the valve that prevents blood from flowing back into the heart from the aorta. It is composed of three leaflets, two of which have the opening to a coronary artery immediately adjacent to them. These arteries then branch and spread out on the surface of the heart.
During systole (contraction) blood flows into the aorta. During diastole it attempts to flow from the aorta back into the heart but the aortic valve snaps shut. Thus there is an increase in pressure on the aortic side of the aortic valve, which drives blood into the coronary arteries. | [
"The heart is typically a muscular tube that runs just under the back and for most of the length of the hemocoel. It contracts in ripples that run from rear to front, pushing blood forwards. Sections not being squeezed by the heart muscle are expanded either by elastic ligaments or by small muscles, in either case ... |
I just read in a wikipedia page on Roman food that rations of wheat were distributed by the Roman state to as many as 200,000 individuals per month (1st century). What other kind of welfare programs did Rome have in place? | Speaking about the republic and earlier empire, and quoting Greg Woolf (Food, Poverty, and Patronage: The Significance of the Epigraphy of the Roman Alimentary Schemes in Early Imperial Italy), “neither charity nor state welfare can be shown to have been significant sources of assistance to the poor in the ancient world,” and as u/XenophonTheAthenian noted above, you have to squint very hard at the Augustan grain dole to make it resemble modern welfare systems.
Since you asked about other kinds of welfare, though, let’s at least go over a few other kinds of not‑welfare-except-if-you-squint. Alimentary schemes and public distributions provided by wealthy individuals are noteworthy among other Roman customs and institutions that might have been beneficial to the destitute. However, both are subject to basically the same type of caveats as the grain dole: there is not much evidence that they were specifically aimed at the lowest strata of society, and there is even contrary evidence, namely, that higher-status beneficiaries customarily were given more.
Public feasts and distributions of food or money were often paid for by wealthy members of a community (for instance, a certain town) for the benefit of other members, and in addition to being paid for as one-off gifts or to mark certain celebrations (weddings, holidays, etc.), were frequently set up in a wealthy individual’s will, by establishing a foundation to provide public giveaways in the deceased’s memory on recurring occasions. These foundations often functioned by being initially endowed with a lump sum of capital and then lending it out at interest, over time recycling the initial capital into new loans and using the interest to fund the benefit that had been set up. The benefit to the giver essentially lay in the purchase of prestige, influence, and/or remembrance.
While such distributions of food and money were benefits to the donor’s community, they weren’t welfare and they weren’t even specifically aimed at the poor (which makes sense considering the aim to gain prestige in life or to be remembered after death; neither of these goals required, or was helped by, focusing particularly on the destitute.). The most that can be said of them from a welfare perspective is that a meal or a money gift might have been more important to the very poorest than to others who received it. But these feasts and distributions were occasional events and often offered smaller gifts to the poor than to the influential, whose gratitude was more valuable.
Second, there were various alimenta. An alimentum was a fund set up to benefit (typically) children of a certain community by paying for their subsistence until they come of age. We know of various privately funded alimentary schemes, often aimed at supporting a certain number of children in the donor’s home community. In the reign of Trajan (or possibly his predecessor Nerva) in the early second century A.D., the emperors got in on what had previously been a private and localized game, with numerous large alimenta schemes aimed at children in various communities in Italy.
These alimentary schemes often, though not always, had a very similar financial basis as that of the feast-providing or gift‑providing foundations: an initial endowment of money is loaned out at interest, and the interest income pays for the benefits. Next to the grain dole, these funds for the benefit of children are the Roman institutions that superficially most resemble modern welfare, and they very likely did help some destitute children, but we have the exact same caveats: there is not a lot of evidence that they were specifically for poor children (or even, in the case of the Imperial alimenta, specifically established in poorer communities and regions), and we do have some evidence that the payments were influenced not by how needy the child was but by their status in the eyes of society – such as boys receiving more than girls.
While the grain dole was an enduring institution, these alimentary schemes generally do not seem to have lasted through the Crisis of the Third Century, which is not surprising considering what the crisis meant for the general Roman economy. There were general shocks to the economy and diminished prosperity during the period of military anarchy, which certainly decreased the resources available to set up these foundations and funds, likely reduced the opportunities for profitable loans for established funds, and likely increased the risks of failure to repay the loans at all. Also, for alimenta that relied on paying out interest while preserving and recycling a fixed sum of initial capital, the high inflation of the crisis years would have been even worse than it was for the economy as a whole.
Other sources of financial aid… well, there were other Roman social institutions that may have been relevant to mitigating financial distress – colleges and societies prominent among them, such as the well-known burial societies – but these operated more along the lines of insurance. Members paid regular dues in return for the institution’s covering sudden, major expenses such as funerals. These have their own histories, being both socially and financially important for their members, but they were even less a form of welfare than the institutions discussed above. | [
"A Roman legionary had two meals per day: The \"prandium\"(breakfast) and the \"cena\"(dinner). For these meals, the soldiers were issued regular rations consisting mainly of wheat, which composed roughly 60–70% of a soldier's total rations. This would be consumed in the form of either bread or porridge. However, w... |
why can certain electrical items turn on for a split second when they're not plugged in? | I've never been able to see an item turn on when not plugged in, but certain ones I've seen remain on momentarily after being unplugged.
Either way, the answer is the same, capacitors. Capacitors are devices that store small amount of electrical energy. They are kinda like really fast charging/discharging batteries, but they hold a very limited amount of energy. A capacitor is essentially just two metal plates separated by a distance. Charge can't cross the gap, but it can build up on either plate. Capacitors have many, many uses.
Many electronic devices have pretty big capacitors in their power circuit. The wall uses AC power, the device uses DC. To convert you from AC to DC, one of the things you need is a capacitor. The capacitor helps smooth out the DC voltage. When unplugged, the capacitor can supply a limited amount of energy before it drains. | [
"Due to the electromagnet in the contactor, if power to the machine should fail the contactor will automatically disengage. Unlike machines with an ordinary latching switch (such as a common light switch), when the power is resumed the machine will not operate until being turned on again. As a result, magnetic star... |
what is a bond and where does that money paid go to? | A bond is a promise to pay someone money at a future date. Governments and business will issue bonds to raise money. Investors give money to the government or business and get the bond in exchange. When the bond matures the government or business will give whoever holds the bond the money that they promised. In between the initial sale and maturity the bond can be bought and sold. | [
"Thus a bond is a form of loan or IOU: the \"holder\" of the bond is the lender (creditor), the \"issuer\" of the bond is the borrower (debtor), and the \"coupon\" is the interest. Bonds provide the borrower with external funds to finance long-term investments, or, in the case of government bonds, to finance curren... |
Is there a limit on the mass of a spaceship built in space? (Due to gravity, etc.?) | The only theoretical limit would be the point at which it becomes a black hole. For a spherical spaceship with radius *r*, the upper limit on mass would be:
m = r*c^(2)/2G
Where *c* is the speed of light and *G* is the Newtonian gravitational constant. | [
"A notable difference between the orbital context of space architecture and Earth-based architecture is that structures in orbit do not need to support their own weight. This is possible because of the microgravity condition of objects in free fall. In fact much space hardware, such as the space shuttle's robotic a... |
If our stomachs churn/mix our food, why don't we feel it moving around? | The stomach isn't innervated with sensory neurons so no feeling, same reason why you don't typically feel any other internal organ doing its job | [
"The vagovagal reflex is active during the receptive relaxation of the stomach in response to swallowing of food (prior to it reaching the stomach). When food enters the stomach a \"vagovagal\" reflex goes from the stomach to the brain, and then back again to the stomach causing active relaxation of the smooth musc... |
if someone receives a full organ transplant will the organ be eventually replaced by the host's cells or will it remain as the the donor's cells for the rest of the host's life. | It will always be the donor's cells. It can be possible to wean off of antirejection drugs as your body gets used to the new organ, but if your whole liver is replaced by a donor liver, you do not have any of your own liver cells to replicate and replace the donor cells. | [
"Many societies have a system for organ donation, in which a living or deceased donor's organ is transplanted into a person with a failing organ. The transplantation of larger solid organs often requires immunosuppression to prevent organ rejection or graft-versus-host disease.\n",
"Bone marrow transplant can rep... |
what is the process for getting a job with mi5/mi6/secret service? | For the US Secret Service, candidates must be U.S. citizens and must submit to urinalysis screening for illegal drug use prior to appointment. All Secret Service positions require a Top Secret security clearance. All applicants must undergo a full, Secret Service-specific, Top Secret clearance process regardless of current existing clearance standings; certain positions may also require the applicant to successfully complete a polygraph and/or medical examination. Age, vision and excellent physical condition requirements may also apply.
If you want to be a secret agent and look like you belong in CSI, [this site](_URL_0_) lists the qualifications | [
"The Chief of the Secret Intelligence Service serves as the head of the Secret Intelligence Service (SIS, also commonly known as MI6), which is part of the United Kingdom intelligence community. The Chief is appointed by the Foreign Secretary, to whom he directly reports. Annual reports are also made to the Prime M... |
AskScience AMA Series: I am pfisico and I build instruments to study the cosmic microwave background radiation. Ask Me Anything! | My question is a bit more basic than the other's here. What is, as you see it, the most important, or most exciting, science currently going on that could use your CMB data?
| [
"Arno Penzias and Robert Wilson of Bell Labs used the Holmdel Horn Antenna located on Crawford Hill to take measurements of the cosmic microwave background radiation. They were awarded the 1978 Nobel Prize in Physics for these efforts that supported the Big Bang theory. For more information, see \"Discovery of cosm... |
Can you heat a metal until it turns into a gas? If so, does this ever happen or is it just a theoretical state? | Absolutely; mercury vapor lights, some metal plateing processes use vaporizing the plateting material. | [
"Often, the metal's sensitivity to heat must also be considered. Even a relatively routine workshop procedure involving heating is complicated by the fact that aluminium, unlike steel, will melt without first glowing red. Forming operations where a blow torch is used can reverse or remove heat treating, therefore i... |
does anything significant happen to our bodies when we are shocked with low-level electricity? | We get shocked. We are mostly composed of water, which conducts electricity, and being exposed to electricity will jolt your whole body. That's why we react so quickly if we've ever been shocked.
It'll probably depend on voltage but it can be anything from muscle pain(including abnormal heart rhythm) all the way to burns. They did use electro shock therapy, maybe that's what ur referring to as low-level? | [
"Electricity is hazardous: an electric shock from a current as low as 35 milliamps is sufficient to cause fibrillation of the heart in vulnerable individuals. Even a healthy individual is at risk of falling from a high structure due to loss of muscle control. Higher currents can cause respiratory failure and result... |
Am I causing myself any harm by heating my food in a plastic container? | Heat will thermally degrade some polymers into their constituent monomers and many of them are *potential* carcinogens. You are more likely to melt the polymer than break it down to monomers at microwave heat, however, so it isn't likely there is substantial contamination. Some contain plasticizers like BPA which may affect hormone signaling. If you want to know more about your specific polymer [this long PDF](_URL_0_) will educate you. | [
"Consumer groups recommend that people wishing to lower their exposure to bisphenol A avoid canned food and polycarbonate plastic containers (which shares resin identification code 7 with many other plastics) unless the packaging indicates the plastic is bisphenol A-free. The National Toxicology Panel recommends av... |
Historically, what has been the most successful form of government for an empire? | This is hard to answer because most empires changed government over time. The Roman Republic lasted centuries, and the Empire lasted over a millennia if you count Byzantium. The Holy Roman Empire did too, but how it was run changed over time. It's impossible to find an unchanged system for any length of time, even if the State or government continues. | [
"Politically, it was typical for either a monarchy or an oligarchy, rooted in the original core territory of the empire, to continue to dominate. If governmental authority was maintained by controlling water supplies, vital to colonial subjects, such régimes were called hydraulic empires.\n",
"Since antiquity, mo... |
During the American Civil War, was Washington D.C. actually the "most fortified city on earth"? | Follow up question, what would these fortifications look like? How large was DC's Garrison? | [
"During the American Civil War (1861–65), Washington County contained a partial circle of defensive fortifications that made Washington one of the most heavily fortified cities in the world at that time. The forts surrounding Union-held territory in Virginia completed the defense circle. The Battle of Fort Stevens,... |
Does climate change effect the occurrence of different cloud types? | The effect that global warming has on clouds is actually a very difficult scientific question! To answer your questions directly though; 1) it would be difficult for a person to notice changes in cloud cover or cloud types without some systematic study - mostly because any significant changes will happen over 10, 20, 30 years and it's just very difficult for humans to notice changes on those timescales (this is also kind of a fundamental reason why we're so bad at dealing with global warming). 2) I can't think of any cloud types that will go "extinct" on a global scale. Most predicted changes involve increases or decreases of either high or low cloud in different regions of the world, so I guess it's possible that certain clouds types could become less common in specific regions. However, a prediction this specific is beyond our current abilities. I'll explain why.
Clouds exist on a huge range of spatial and temporal scales; from tiny water droplets to country-sized banks of clouds. They also depend on the global and local winds, temperatures, water availability, geography (i.e. mountain ranges), etc. Basically they're really complicated! One way we can make predictions about global warming is with computer models, where we divide up the global atmosphere into boxes, and for each box we have a set of equations to predict what will happen within it. The size of the boxes is the resolution (think of it like pixels on a screen). The difficult thing with clouds is they can be smaller than the box, which means you can't explicitly model every cloud. Instead you use equations that tell you the average effect of clouds within each box. On a global scale this is quite good at telling us how "average" clouds will change, and what that effect on the climate might be, but it's very difficult to say exactly what will happen on smaller scales, and clouds remain a major uncertainty in future climate change predictions, e.g. [ipcc](_URL_0_).
Hope that answers your question, happy to clarify anything. | [
"The number and type of CCNs can affect the precipitation amount, lifetimes and radiative properties of clouds as well as the amount and hence have an influence on climate change; details are not well understood but are the subject of research. There is also speculation that solar variation may affect cloud propert... |
portuguese drug laws | Well, I'm portuguese. My only experience is with marijuana so I will only talk about it. Marijuana isn't legal, but it isn't really criminalized, I mean, you can have with you up to 5g, if you have more, you'll be charged with Possession of drugs, but less than that it's generally fine.
About smoking, some places are cool with it, others may ask you to stop it, others may call the cops. Really depends on the person itself.
Sometimes cops that catch you smoking will take it from you and walk away, other times they'll just ask you to do it somewhere more privately. | [
"The drug policy of Portugal was put in place in 2001, and was legally effective from July 2001. The new law maintained the status of illegality for using or possessing any drug for personal use without authorization. However, the offense was changed from a criminal one, with prison a possible punishment, to an adm... |
what is the science behind being a good socialiser? what makes a 'good conversation'? | The gift of bullshit is an important one. That's number one. Second, it does help to be educated across the board, but if this fails, fall back on number one. Don't talk about yourself either. Not everything has to relate back to you. Those people are the worst. | [
"BULLET::::4. Be a good listener. Encourage others to talk about themselves. The easiest way to become a good conversationalist is to become a good listener. To be a good listener, we must actually care about what people have to say. Many times people don't want an entertaining conversation partner; they just want ... |
in print, especially transcribed interviews, what is the reason for the brackets? "jane said [tom] never had a bad thing to say about anyone." | The brackets are usually replacing a pronoun, a nick-name or first or last name only when context isn't present to make it clear who they're referring to.
It would say something like "Jane said he never had a bad thing to say about anyone", which is confusing if they haven't specified that it's Tom they're talking about (or she referred to him by, say, "T-Dawg" or some shit like that). It's always just to clarify and the brackets mean that those words were substituted for other words for the sake of understanding. | [
"That and almost everything else could be forgotten amidst Jane Ace's linguistic mayhem, much of it provided by her wry husband's scripts and enough improvised by her. (Mary Hunter's real laughter, at Jane's malaprops or Ace's arch barbs, was practically the show's laugh track, years before anyone ever thought of u... |
Why does 2-stroke engine exhaust smell different from 4-stroke? | Primarily because in a 2-stroke engine there's no dedicated lubrication system, so you have to mix oil directly into the gas. The combustion of that oil means you end up creating a lot of smoke compared to pure gas, which burns cleaner.
Additionally a car is going to have a lot more bells-and-whistles related to clean combustion, like a catalytic converter that cleans up exhaust. | [
"The engine is also 4-stroke — unusual when almost all pedal-equipped mopeds used simpler 2-strokes. Soichiro Honda disliked the sharp noise of 2-strokes, and the 4-stroke does not require oil to be mixed with the gasoline at every fill-up.\n",
"Unlike a four-stroke engine, whose crankcase is closed except for it... |
how a sql index works? | Imagine I've got a pile of Lego, and I'm looking for a piece. Without an index is like looking at every piece individually until I find the one I'm looking for.
If I made a note of every piece of Lego was when I took it out of the box, when I wanted to find a piece, I could look up this list of Lego pieces and it would tell me where to find the one I wanted. | [
"A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes and storage space to maintain the index data structure. Indexes are used to quickly locate data without having to search every row in a database table every time a database... |
why are islamic extremist groups predominantly sunni muslims rather than shia? | Sunni Muslims make up about 85-90% of all muslim groups, however there are a pretty large percentage of Shia Muslim extremists, because of the Shiite population in Iran, Iraq and other areas in politically unstable regions (Sunni's are also in this area, but are more concentrated to Eastern Asian areas and Northern Africa. | [
"Within Islam, there has been conflict at various periods between Sunnis and Shias; Shi'ites consider Sunnis to be damned, due to their refusal to accept the first Caliph as Ali and accept all following descendants of him as infallible and divinely guided. Many Sunni religious leaders, including those inspired by W... |
what does it mean when the potus says that china is illegally manipulating it's currency. | You trade 2 baseball cards for 2 candy pieces, or you can trade 2 cards for 2 sandwiches, or 2 cards for 2 books. But then a new kid shows up and starts giving you a trade at 2 cards for 4 candies. Pretty sweet deal, you start trading a lot with that new kid.
Baseball Cards = $US Dollar. Candy = Chinese Dollar (Yuan).
Here, someone is using $2 to buy 400 Yuan (2 cards for 4 candy). Normally if they do this a ton they you should charge $3 for the 400, then $4 for 400, and so on. So, normally the Chinese dollar should go up and the US vs Yuan would go down.
However, the kid giving you the sweet deal is getting really good experience running his business, and he wants to keep it going (he was really poor before), but knows people will stop when it's more expensive. So what the kid does is artificially buy more baseball cards, so that his candy value goes back up, even if he has no plans on really using them. This continues the cheap trades for longer and longer.
_____
This is what China is doing. They are keeping their dollar low so people can buy their goods cheap. Normally you'd need Chinese people buying US computers or US cars for the dollars to be more equal, but the Chinese government is just buying lots of US bonds/property/etc. on their behalf.
> How does doing so effect the global economy?
When I was last looking at global economics (2-ish years ago) most people considered the US/China relation to be a really unstable dance that was going faster and faster. Both sides were getting *really* rich off each other, China was growing super fast, American citizens were filling their house with more stuff from Walmart. People looking in were like "jeezu christ!, grow at 2% a year not 12%!".
> Why does the US get so mad about it?
If the US wants to compete at candy (manufacturing, cheap factory work) they're fighting stacked terms. They can't compete with the cheaper Chinese dollar, which is kept artificially low. Note the POTUS needs to walk a fine line of complaining about their low dollar, while their businesses buy billions of dollars of stuff from them the very next minute. | [
"Trump has vowed to label China as a currency manipulator on his first day in office. \"Washington Post\" fact-checker Glenn Kessler, citing experts such as C. Fred Bergsten, found that \"Trump's complaints about currency manipulation are woefully out of date,\" noting that \"China has not manipulated its currency ... |
Is there information on the distribution of stars by metallicity? | Overall disclaimer: The metallicity of any given star is a complex mess, especially when you start talking about stars cooler than our Sun (which represent the bulk of stars). It's really tough to measure the overall metallicity of a given star, even with high resolution spectroscopy, and it's doubly complicated when trying to talk about it using just [Fe/H]. Distances for most stars are difficult to pin down much past 500 parsecs (~1600 light years) until [ESA's GAIA mission](_URL_0_) launches, though it's possible to get rough approximations through other methods with significantly higher uncertianties.
You seem to be interested in what's usually called the metallicity distribution function, and in practice it's restricted to specific stellar populations to avoid contamination from other galactic components. Stars in the galactic halo, bulge, and disk represent different epochs of star formation, and, as such, will probably have different average metalicities. Low metallicity stars represent a much, much higher fraction for stars in the halo vs. those in the disk, for example, though the intense star formation in the galactic bulge during our galaxy's formation left a number of old, metal poor stars in the galactic bulge as well. The wiki page on [metallicity](_URL_1_) is...okay for an introduction to the stellar populations topic as a whole, though that figure is probably too simplistic.
All in all I don't want to throw off numbers off the top of my head since I'm not familiar with some of the newest work, but a galactic structure person might be able to chime in with more information. If you're up for a technical read, the [SEGUE project has a paper considering the MDF of G and K stars](_URL_2_). You can check out some of the figures attached at the end of the PDF, specifically Fig. 16, where they examine [Fe/H] trends for G and K stars as a function of height above the galactic plane, but again, this is a restricted population of stars. | [
"A star's metallicity measurement is one parameter that helps determine whether a star has planets and the type of planets, as there is a direct correlation between metallicity and the type of planets a star may have. Measurements have demonstrated the connection between a star's metallicity and gas giant planets, ... |
if 0.1 amps can be lethal to a human, then why don't i die when touching the contacts of a phone battery, which is 3.8 v and 1500-3200 ma? | When you touch the contacts of a battery, the current that flows through your body is governed by [Ohms law](_URL_0_).
Because your body, and in particular your skin, has a high electrical resitance, the current that results from a 3.8 Volt potential difference is in the range of micro Amperes, which typically will not register with your nervous system.
The number 1500-3200 that you mention is a measure for how much electrical energy can be stored in the battery, and it is usually expressed in milli Ampere hours (mAh). A capacity of 1500 mAh means that your battery is able to sustain a current of 1500 mA for the duration of one hour before it is depleted. Or 750 mA for a duration of two hours. Or 15 mA for a duration of 100 hours. | [
"Voltages greater than 50 V applied across dry unbroken human skin can cause heart fibrillation if they produce electric currents in body tissues that happen to pass through the chest area. The voltage at which there is the danger of electrocution depends on the electrical conductivity of dry human skin. Living hum... |
How much gas could the world economy save daily by capturing the pump spillage after fueling up? | There was something on Gizmodo about this the other day: _URL_0_
| [
"The world's first industrial extraction of natural gas started at Fredonia, New York, USA in 1825. By 2009, 66 trillion cubic meters (or 8%) had been used out of the total 850 trillion cubic meters of estimated remaining recoverable reserves of natural gas. Based on an estimated 2015 world consumption rate of abou... |
How ubiquitous are infectious germs on household surfaces? | I wouldn't call any surface in a home sterile. Go ahead and take swabs of any surface and grow them, you will find growth. Even the dust from our skin contains germs, and that flies everywhere. Wind carries spores, and the air isn't pure since even a virtually airtight home still has it's doors opened and dirty occupants come in. Mold and fungus, bacteria, viruses, and possibly prions are everywhere that I've ever tested. Ahh, but now that I reread you question, I'll rephrase. Germies are everywhere; infectious germies are not. | [
"Scientists are still trying to understand the microorganisms within PM particles and how they are spread through pollutants. Research indicated that many kinds of pathogens and bacteria can be spread through PM smog and cause diseases. For example, Chinese researchers have found that smog in Beijing contains signi... |
Why didn't China save Pakistan from India in 1971? | China wanted to avoid the war in South Asia as much as they could. They wanted Pakistan to come up with a political solution and to end it as soon as possible. Furthermore the Chinese realized that a war with India would not be as easy as it was in 1962.
India had a 'friendship treaty' with the Soviet Union, meaning that "Moscow and New Delhi [were] obliged to consult when either [was] threatened with attack. Since the Russians [were] known to want no part of a conflict that could bring China in on Pakistan's side, they [had] thus suggested that India move with care."
India was advised by the Russians to try its best to not provoke the Chinese into joining the war. And of course this treaty meant that the Russians were now involved in the war (In a limited support and advisory role, but still involved) so the Chinese were also being cautious not to escalate.
One of the reasons why the Chinese were so successful during their war with India was because the Indian army was caught by surprise. This was no longer the case in 1971, as India had fortified the border with China and were preparing for a possible Chinese retaliation. On top of this the Himalayan region was facing heavy snowfall, which would have made a Chinese advance into India much more difficult.
And finally, India's official involvement in the war only lasted 13 days. The Eastern Pakistan forces surrendered less than 2 weeks after Pakistan attacked India. A relatively short time for a war. The Indian army did not continue with its advance into West Pakistan. However, if it did and chose to continue the war, I doubt the Chinese wouldn't have stepped in.
Source: Time. 12/6/1971, Vol. 98 Issue 23, p34. 7p. _URL_0_ | [
"While Western nations did not view Chinese actions favourably because of fear of the Chinese and competitiveness, Pakistan, which had had a turbulent relationship with India ever since the Indian partition, improved its relations with China after the war. Prior to the war, Pakistan also shared a disputed boundary ... |
why are brass knuckles called knuckle dusters? | Duster comes from the type of coat, and I suspect that it refers to a covering for your knuckles.
_URL_0_ | [
"Brass knuckles, also sometimes called knuckles, knucks, brass knucks, knucklebusters, knuckledusters, an English punch or a classic, are weapons used in hand-to-hand combat. Brass knuckles are pieces of metal shaped to fit around the knuckles. Despite their name, they are often made from other metals, plastics or ... |
Was Atahualpa immune to smallpox? | Could you elaborate a bit? Are you asking if he contracted smallpox prior to Cajamarca? | [
"In the years between 1524 and 1526, the European germ smallpox, introduced from the conquistadores in Panama and preceding the Spanish conquerors in Peru through transmission among natives, had swept through the Inca Empire. Smallpox caused the death of the Incan ruler Huayna Capac as well as most of his family in... |
How can anything ever reach any event horizon ? | According to an external observer, yes, that's completely correct. According to the poor bloke falling into the black hole, there's nothing special about the event horizon, just a continuation of the same old impending sense of utter doom. | [
"There is an event horizon in the universe where light (and therefore any information) cannot and will never be able to reach an object, because the cosmic acceleration outpaces the speed of light: the cosmological comoving horizon. If the object accelerates in one direction, a similar event horizon is produced: th... |
why can't the us (or any country in general) alleviate their external debt by collecting their external credit? | When you are talking about debt on a governmental scale, that is a highly structured, desirable investment option.
It is not like when you borrow fifty bucks to a friend and you can call up tomorrow and demand your money back. When money is loaned to the government, it is in the form of a bond. A bond has very specific terms of agreement, interest and payment times. You cannot collect early on a bond (you can sell it to someone else though if you need cash immediately). Everybody involved has to stick to the terms. It cannot be repaid early, but it can also not be demanded back early.
What the US government could do, theoretically, is cancel out a lot of those bonds because the US government is one of the biggest holders of US bonds. Think of it as the right hand owing the left hand money.
Of course the US government does not want to do this, because there is nothing wrong with government debt, at least not at the level it is at in the USA. Interest on government bonds is low, confidence in the US economy is high among investors. The US government has never missed a payment of interest on any of their outstanding bonds. Right now, again because the interest is so low, pretty much everything the USA government does with the money it borrow will make them more money than they have to pay back. | [
"Governments create debt by issuing government bonds and bills. Less creditworthy countries sometimes borrow directly from a supranational organization (e.g. the World Bank) or international financial institutions.\n",
"Since a sovereign government, by definition, controls its own affairs, it cannot be obliged to... |
At what level does the circulatory system of each indivdual start to differ? | Most of the major named arteries follow the same course, but there's a great deal of variation. There isn't some set point at which they occur (it's not like you can say '3 branches off the aorta, things start to diverge'), but generally smaller vessels and areas with a lot of anastamoses tend to feature more variability. One common and clinically relevant example is in the coronary arteries of the heart - the posterior descending is usually a branch off the right coronary, but can also branch off the left circumflex, or both. Another common site of variation is in the circle of Willis, which supplies the brain. Capillaries pretty much just go where they are needed, and don't necessarily follow a set path. | [
"A circulatory anastomosis is a connection (an anastomosis) between two blood vessels, such as between arteries (arterio-arterial anastomosis), between veins (veno-venous anastomosis) or between an artery and a vein (arterio-venous anastomosis). Anastomoses between arteries and between veins result in a multitude o... |
How did medieval Russia interact with its nomadic Asian neighbors prior to the Mongol invasion? | I have a great deal of information on the subject, but I'm a little busy looking for information on another subject right now. Reply to me and I'll get back to you after I've gotten some work done on my paper.
Here's the real quick and dirty of it: Russian principalities interacted with steppe nomads a lot like how the nomads interacted with each other. There was a lot of raiding back and forth, some trade and diplomacy, and even intermarriage. Things were complicated by the fact that the Rus' were predominantly Christian and the steppe nomads were mostly Muslim. Russian writers of the time characterized any conflict, including the most bold-faced "for profit" raids, as holy war against infidels, and the trading and intermarriage was ignored as much as possible. | [
"Mongol invasion of Rus can be divided in two phases. In winter of 1237-38 they conquered Northern Russia (principalities of Ryazan and Vladimir-Suzdal) with the exception of Novgorod, but in spring of 1238 retreated back to Wild Fields. The second campaign, aimed to Southern Russia (principalities of Chernigov and... |
Is it possible that psychedelics like psilocybin increase the spectrum of colors that we can see? | It really doesn't physically change how many colors we can see or how we hear. Your visual receptors have a specific range of wavelengths that they can detect, same with your ears. Taking a psychedelic won't change this fact. Psychedelics change your brain chemistry in certain ways that can make you see colors you wouldn't normally see or hear things you wouldn't normally hear, but this is due strictly to chemical balances in your brain. You aren't "seeing" these new colors with your eyes; your visual cortex is creating them while you are under the influence of the drug. | [
"Psychedelic experience includes the full range of mystical or religious experiential phenomena. Two scientific studies have concluded that psilocybin (a typical psychedelic compound that occurs naturally in psilocybin mushrooms) reliably triggers mystical-type experiences. The more recent study at Johns Hopkins Un... |
is there a link between diet soda consumption (i.e. aspartame) and cancer? if not, why does the general public continue to think there is. | There are biased, non-peer-reviewed studies that make this link, but there's no real evidence of any link. Unfortunately some people like to latch on to any study that promotes FUD without considering any of the facts. | [
"In a report released on 10 December 2013, the EFSA said that, after an extensive examination of evidence, it ruled out the \"potential risk of aspartame causing damage to genes and inducing cancer,\" and deemed the amount found in diet sodas an amount safe to consume.\n",
"Coca-Cola has been under fire since 201... |
what determines the strength of someones vocal chords, e.g. how loud they are? | Loudness comes much more from breathing than from your vocal chords. The more air you can push past them, the louder you can be.
Vocal coaches will tell you to practice breathing from the diaphragm which isn't as easy or natural as it may seem. There are tons of videos on YouTube demonstrating this. Basically try taking a deeper breath than usual and then exhale, pushing more air out of your lungs when you speak or sing, and you will notice your volume go up. | [
"The perceived pitch of a person's voice is determined by a number of different factors, most importantly the fundamental frequency of the sound generated by the larynx. The fundamental frequency is influenced by the length, size, and tension of the vocal folds. This frequency averages about 125 Hz in an adult male... |
why does japan have such a high conviction rate? | Fewer rules against how evidence is gathered, so the discovery and investigation parts of the system are faster with fewer pieces of damning evidence thrown out due to "procedural" or "paperwork" errors. | [
"Japan has a conviction rate of over 99%. In several cases, courts have acknowledged confessions were forced and released those imprisoned. To combat this, a law was passed in 2016 requiring some interrogations to be videotaped. However, this only applies to people accused of serious crimes, such as murder, arson a... |
why do some people get annoyed when you say america instead of the united states? | Depends on what you mean by 'most people.' It's that attitude that annoys people. I don't have a problem with it myself, and am used to saying it, but that's because I'm from the U.S. Someone from outside the U.S. but who is also from 'the Americas' might take offense that we are claiming everything as our own like colonialists or ignoring everyone else like elitists , and I've been told that the rest of the world hates the U.S. for similar reasons. | [
"BULLET::::- US/America/North America: The terms 'America' and 'American' are frequently used to refer only to the United States and its people. This sometimes causes resentment among some non-US Americans, especially Latin Americans, who tend to respond by referring to the people of the US as Unitedstatesian (or '... |
What would happen to a single photon in a perfect vacuum? | A photon in a perfect vacuum will travel in a perfectly strait line until it hits something. If you put a photographic plate in the way, you would see one dot of light surrounded by darkness. | [
"BULLET::::- Perfect vacuum is an ideal state of no particles at all. It cannot be achieved in a laboratory, although there may be small volumes which, for a brief moment, happen to have no particles of matter in them. Even if all particles of matter were removed, there would still be photons and gravitons, as well... |
Can 3 objects orbit each other? | Yes, it's not super rare. The most common configuration is that two of them are much closer together than the third one, and they orbit each other while the third one orbits both of them (Alpha Centauri may be like this).
_URL_0_ | [
"Considering possible hovering positions or orbits of the tractor around the asteroid, note that if two objects are gravitationally bound in a mutual orbit, then if one receives an arbitrary impulse which is less than that needed to free it from orbit around the other, because of the gravitational forces between th... |
How does heat transfer within a solid differ from heat transfer between a solid and air (convection)? | In equilibrium, everything will reach the same temperature. If we assume that the room as a whole is a closed system, the answer is as easy as calculating the total heat capacity and the total heat.
Let's make the problem even easier: We have a small room of 10 m^3 in volume. In this room, we have an iron cube that weighs 1 kg. Air has a heat capacity of about 1 J/(g K) (according to [this website](_URL_0_)), iron has about half that, 0.45 J/(g K).
The air inside the room has a density of about 1.2 kg/m^3 (wikipedia), so we have about 12 kg air inside our room. The total heat capacity of the air is, therefore, 12 J/K and the heat capacity of the iron cube is 0.45 J/K.
So, if we dump some amount of energy into the room, about 27 times as much energy would go into the air than the iron. Or, in other words, to heat the air by 1 K, the block would have to be 27 K above room temperature.
If you're asking about the dynamics of the heat transfer, the answer will be a lot more complex. It depends on the material properties and shape. | [
"In conduction, the heat flow is within and through the body itself. In contrast, in heat transfer by thermal radiation, the transfer is often between bodies, which may be separated spatially. Also possible is transfer of heat by a combination of conduction and thermal radiation. In convection, internal energy is c... |
why are languages all so different... but body language is so similar everywhere? eye-rolls, shrugs, clapping, skeptical eyebrow raises etc.. | Body language is *not* similar everywhere. In fact, some gestures mean exactly the opposite of what you expect in other cultures. [Here's a page](_URL_0_) that talks about the topic.
And [another](_URL_1_) short page with some of the confusing gestures from around the world.
| [
"Languages, understood as the particular set of speech norms of a particular community, are also a part of the larger culture of the community that speaks them. Languages differ not only in pronunciation, vocabulary, and grammar, but also through having different \"cultures of speaking.\" Humans use language as a w... |
How do the antibodies in a blood donors blood behave in the blood recipients body? | They work just fine; this is basis of [immunoglobulin therapy](_URL_0_). However, they don't work very long; half-life of various immunoglobulins is only a few days.
What blocks the significant response from the recipient's immune system is that the recipient has to be immunosuppressed to receive a transplant (in which I include whole-blood transfusion).
Also worth noting: most cases in which you receive blood from someone, you don't get whole blood — you get only some parts of it (for example, red blood cells or plasma), and those parts don't include antibodies. It's only when you receive whole blood that you are getting everything, and that works pretty much like any transplant does. | [
"Blood donors with exceptionally strong anti-A, anti-B or any atypical blood group antibody may be excluded from blood donation. In general, while the plasma fraction of a blood transfusion may carry donor antibodies not found in the recipient, a significant reaction is unlikely because of dilution.\n",
"The dono... |
why does a muscle become stiff when cold and limber when hot? | When cold, blood vessels contract so they are further from the skin's surface, losing less heat. This constriction means blood does not flow through the veins as much, limiting blood flow to muscles.
When hot, blood vessels expand so they are closer to the skin's surface to release heat. Wider vessels means more blood flow. | [
"Increased muscular activity results in the generation of heat as a byproduct. Most often, when the purpose of the muscle activity is to produce motion, the heat is wasted energy. In shivering, the heat is the main intended product and is utilized for warmth.\n",
"Ice can be used to decrease inflammation of sore ... |
How do extended-reach oil wells change direction underground? | Not my field of specialty but since no one has chimed in yet I'll give it a go:
[Directional Drilling](_URL_1_) can be done by controlling the orientation of the drill-bit at the bottom of the hole. I think usually it is accomplished by [hydraulic actuators](_URL_0_) located on the sides of the drill bit. These actuators push against the walls of the hole and thus can control where the tip of the drill points. Of course you have to have some sensors so you can determine the current orientation of the bit. It also requires the walls of the hole to be strong enough to support the stress of the actuators so the rig-workers add casing and liners to strengthen the well. | [
"The earliest oil wells in modern times were drilled percussively, by repeatedly raising and dropping a cable tool into the earth. In the 20th century, cable tools were largely replaced with rotary drilling, which could drill boreholes to much greater depths and in less time. The record-depth Kola Borehole used non... |
how do radio signals (4g, wifi etc.) manage to retain their information after passing through trees, buildings and other obstacles? and how are they not mixed up, intertwined? | They are, the key is there are error correction and detection algorithms that work to counter the problem. In bad environments they don't always work.
Also, many newer devices actually utilize the attenuation and reflections to improve signal quality. Take a look into [MIMO](_URL_0_) technology. They do what is called [beamforming](_URL_1_) where they vary the signal being output on multiple antennae to create hot spots in the signal at the receiving antenna(e) to improve reception. When multiple devices are connected it will actually change the beam forming per device moment to moment depending on the destination. It's really cool stuff.
Edits: Links, typos.
Edit 2: Figured I could expand as well. When you're dealing with reflections or other signals that could potentially interfere, they are usually a bit weaker than the main signal. This means that a receiver can filter them out by simply ignoring signals that are weaker than a certain level. This is called the noise floor of the radio. Think of it like being in a room full of people talking and ignoring all the background conversations because they're harder to hear and focusing on your current one.
Attenuation of the main signal works similarly. As long as the signal isn't attenuated below the noise floor, it will work. If the operating environment for the radios is bad enough, it may be impossible to get a strong enough signal to overcome the noise floor, and then nothing works. | [
"BULLET::::- Cognitive radio techniques: each radio measures the spectrum in use and communicates that information to other cooperating radios, so that transmitters can avoid mutual interference by selecting unused frequencies. Alternatively, each radio connects to a geolocation database to obtain information about... |
how do skin grafts work? | " how does that help the area you took it from."
It doesn't hurt it because you only take a small amount. It's more like gary has two apples, and both of your apples explode, so now you're going to starve. Gary gives you one apple so you won't starve, and now only has one apple.
BUT NEITHER YOU OR GARY WILL DIE AND THE FUCKING APPLES GROW BACK | [
"Skin grafting is patching of a defect with skin that is removed from another site in the body. The skin graft is sutured to the edges of the defect, and a bolster dressing is placed atop the graft for seven to ten days, to immobilize the graft as it heals in place. There are two forms of skin grafting: split thick... |
if a planet or meteor the size of pluto collided with earth what would it be like for the people on the opposite side of earth? what would they see or feel? | We would all be dead | [
"A large asteroid or comet could collide with the Earth's surface with the force of hundreds to thousands of times the force of all the nuclear bombs on the Earth. For example, the K/T boundary impact has been proposed to have caused extinction of all non-avian dinosaurs 66 million years ago. Early estimates of thi... |
washington dc | Well... for one the whole point of the thing is that *it isn't a state or a part of a state*.
Its a neutral ground. Beholden to no state so that the Federal Government (representing all 50 states) can conduct its business.
So the reason no state (basically Virginia and Maryland) is trying to annex DC is because that's the whole point of the place and the other 49 states might get pissed about that. | [
"Law enforcement in Washington, D.C. is complicated by a network of overlapping federal and city agencies. The primary agency responsible for law enforcement in the District of Columbia is the Metropolitan Police Department (MPD). The MPD is a city agency headed by the Chief of Police, currently Peter Newsham, who ... |
when the internet goes down in my neighbourhood, what normally happened? how is it fixed? | You probably have a router or a switch that lets you connect several computers at once to your single internet connection. Simply put, your ISP has larger, more powerful routers and switches that Connect the neighbourhood to a larger part of the internet.
something with these probably failed. it could be a software error, broken hardware that they had to replace, or a power failiure.
The ISP usually notices it pretty fast, though, as it is common to have surveillance tools pay attention to whenever or not their boxes are alive and talking. | [
"Under certain conditions, a network component shutting down can cause current fluctuations in neighboring segments of the network leading to a cascading failure of a larger section of the network. This may range from a building, to a block, to an entire city, to an entire electrical grid.\n",
"One way natural di... |
why is the law to own a pistol 21, while to own a long gun is 18? | It isn't everywhere, it varies by State. As far as potential
Justifications for it, Long guns can be used for hunting, and are good for self defense in the home as well. Hand guns are good for concealement, and are the weapon most likely to be used in crimes. | [
"At the age of 18 or up, it is legal to buy a pistol with a purchase license from a private seller, at the age of 21, it is legal to buy a firearm from a Federally licensed (FFL) dealer. No purchase license is required to purchase a long gun (a firearm that is more than 26 inches long) in Michigan. According to sta... |
How far do slugs travel? | Based on a quick google search, a slug can travel .013 meters per second, and typically lives for 18 months. At this rate if it slept 1/3rd of it's life (based on snail numbers, didn't see anything in 5 seconds of searching around for slugs), it would travel a maximum total of 254 miles in it's lifetime. Slugs like to travel underground though, so I'd say it's likely total travel much less than this number. | [
"These sea slugs sometimes occur in abundant numbers during breeding time, swarming with over 1,000 individuals per square metre, as has been observed on numerous occasions. These swarms are all oriented in the same direction, determined by the flow of the tide. They follow each other at the same speed, forming col... |
one of the primary enemies of nazis were communists. so why did stalin ever make a pact with hitler in the first place? | The pact wasn't an alliance. It was a non-aggression pact, so that each would keep out of the other's business.
It didn't work. | [
"As Stalinism came to dominate the Comintern, the united front strategy was dropped. In the period preceding Adolf Hitler's electoral victory in Germany, the Comintern argued that the social democrats were \"social fascists\" and that they, rather than the Nazis, represented the real danger. Following Hitler's vict... |
how to buy stocks(from a company)? | You can buy stocks from any brokerage, some of the bigger national ones are Charles Schwab, etrade, Scottrade, Morgan Stanley, and even many of the major retail banks.
I think at your current knowledge level, you should consider buying index mutual funds, instead of trying to day-trade stocks, or other more advanced trading techniques. Otherwise it's gambling, not investing.
I would check out /r/personalfinance for more information. | [
"There are other ways of buying stock besides through a broker. One way is directly from the company itself. If at least one share is owned, most companies will allow the purchase of shares directly from the company through their investor relations departments. However, the initial share of stock in the company wil... |
Is this a meteorite? (Here are pictures and surface x-ray results) | The high ferrite composition and the mix of some heavier elements(though in fewer percentages) would lead one to believe it might be a meteorite. The resource places are going to do the exact same thing you did. They're gonna use probably a higher end x-ray spectrograph and get more accurate results. Your best bet is to go to your local university physics/chemistry/astronomy department and talk with an administrator or professor. The weight of 225oz (14lbs) seems very low since the surface composition contains a lot of iron. It could be very porous on the inside.
One thing you could do.. is measure the volume (immersing in water, measuring the displaced water (1g of water = 1cm^3 ) using this you could estimate the weight if it were a solid piece of 70%iron ie. rho_iron*0.7*V etc.) using this you could hesitate a guess as to if the sample is porous on the inside, though this is just to estimate and should only be used for a general idea.
Also.. i noticed 3.4% of it is Palladium.. considering Palladium is a very rare earth metal and super expensive.. if we assume this is true.. we have between 6-8(8-10 troy oz) of palladium which is selling around 600-700 a troy oz.. You seem to have a lot of money worth of rare minerals.. indium, rhodium, cadmium,silver.
I would hesitate to say it's space junk due to the heavier elements involved, but the weight is what concerns me.. most meteors (A chunk they have at the Arizona crater, is about 4-5basketballs big and weights 200+lbs if i recall correctly..) are very heavy.
*edit*
added some additional ideas/thoughts
*Note* im currently an undergrad physics student, i have read a lot about meteorites and other information, but i cannot say for certain i am an authority, i would estimate myself between layman and knowledgeable on this topic, feel free to correct/disregard this information (if mods want me to remove this i will) | [
"Caroline Smith, meteorite curator at the Natural History Museum in London, stated that the pictures and video footage of the burning crater indicated that it was not a meteorite crater: meteorites are not aflame when they strike Earth. Smith also pointed out that there were no other reported sightings of any fireb... |
what is that bright halo around light that we always see? | You have two components in your eyes that actually "see". They are called "Rods" and "Cones". "Rods" are spread throughout your retina while "Cones" are almost exclusively found in your Fovea (the middle of your visible range where there is a dense cluster of cones). The perception of these different components actually varies quite a bit. Rods see a very limited range of color and are typically thought of as black and white vision although this isn't completely true. Cones can see color, but they aren't as sensitive to low light conditions as Rods. So, if you focus on an object, you are looking at it mostly with Cones. If you saw a picture of what you actually see, it would look like two pages that are mostly bluish gray blurry with a small circle in each that is in focus and in color. There would also be a black spot in each where the optic nerve connects (your blind spot). What we perceive is a trick. The back lobe of our brain does nothing but process what we see into a more usable image that our conscious mind works with. This is why you may see something move out of the corner of your eye that turned out to be nothing like what you thought you saw.
Anyway, when you look at a bright light, your rods and cones are picking it up, but the rods pick it up more intensely. This is why in the transition between the rods and cones, you actually see a re intensifying of the light or a "halo". Another neat trick, if it's really dim, you can actually see better by focusing on a point near where you are looking than actually on what you want to see. (like look 10 degrees away from the object) This is because you will be using more rods than cones, and they are more sensitive to low light conditions. | [
"In optics, the Arago spot, Poisson spot, or Fresnel bright spot is a bright point that appears at the center of a circular object's shadow due to Fresnel diffraction. This spot played an important role in the discovery of the wave nature of light and is a common way to demonstrate that light behaves as a wave (for... |
el15: how many fps does the human eye see? | This article goes into great detail about how the human eye interprets movies and the real world.
_URL_0_
For those that don't want to read, this quote pretty much sums it up.
" Seeing framewise is simply not the way how the eye\brain system works. It works with a continuous flow of light\information."
An example they use is that a movie of a slow moving fog can seem fluid at extremely low framerates ( < 10) because of it's lack of sharp edges and fast movement.
On the other hand, fluidity a game, where quick movement and high detail are present, can be greatly affected by framerate. It's pretty easy to see a difference between 30 and 60 fps, and higher refresh smooth things out even more.
The human eye can discern fluid movement at a wide range of fps, but when viewing the real world, it does not see in "fps", as light is constantly streaming into it and being processed.
***apologies for poor formatting. Mobile user*** | [
"The human eye can detect a luminance range of 10, or one hundred trillion (100,000,000,000,000) (about 46.5 f-stops), from 10 cd/m, or one millionth (0.000001) of a candela per square meter to 10 cd/m or one hundred million (100,000,000) candelas per square meter. This range does not include looking at the midday ... |
Why doesn't all the hydrogen in the sun undergo fusion simultaneously? | When two hydrogen nuclei (protons) managed to slam together hard enough to fuse, they form a "diproton" (effectively a Helium-2 nucleus). This is a hideously unstable particle, and the vast majority of them simply immediately decay back into two protons, to no net effect. The tiny fraction that instead decay into deuterium (one proton becomes a neutron) is what drives the [proton-proton fusion cycle](_URL_0_). The incredible slowness of this first step is what lets the Sun continue shining for billions of years; if it was faster, it would've burnt out long ago (although it probably still wouldn't happen *instantly*, due to the effects mentioned by others in this thread). | [
"Because lithium-8 and beryllium-12 form natural stopping points on the table of isotopes for hydrogen fusion, it is believed that all of the higher elements are formed in very hot stars where higher orders of fusion predominate. A star like the Sun produces energy by the fusion of simple H-1 into helium-4 through ... |
why do fat/obese/overweight people generally have a lot of strength even if they do not work out? | They gotta carry their fat ass everywhere they go | [
"Obesity induced from lack of exercise also contributes to a decrease in general mental health. Overweight children and teens are more likely to suffer from poor self-esteem, negative body image, teasing, and bullying.\n",
"Obesity is a physical marker of poor health, increasing the likelihood of various diseases... |
if a 5 year old were to fall into a coma and wake up 20 years later, how would they act? | Probably like a two year old.
You don't spend 15 years in a coma and come back without some severe mental deficits. | [
"People may emerge from a coma with a combination of physical, intellectual, and psychological difficulties that need special attention. It is common for coma patients to awaken in a profound state of confusion and suffer from dysarthria, the inability to articulate any speech. Recovery usually occurs gradually. In... |
Who actually wrote the Magna Carta? | I was going to summarise [this lecture](_URL_1_) from May but fortunately _URL_2_ has it online! The person giving this paper is one of the leads on the AHRC-funded [Magna Carta Project](_URL_0_), which represents the culmination of several years of study by scholars from the University of Easy Anglia and Kings College London including several notable authorities on thirteenth-century England such as Nick Vincent and David Carpenter. | [
"Magna Carta is an English charter originally issued in 1215 which influenced the development of the common law and many later constitutional documents, such as the 1689 English Bill of Rights, the 1789 United States Constitution, and the 1791 United States Bill of Rights. \n",
"\"1215: The Year of Magna Carta\" ... |
Magnitude or depth, which is more important to strength of an earthquake? | In terms of perceived strength at a location (i.e. the [intensity of an earthquake](_URL_1_)), both the depth and magnitude will matter, as will horizontal distance from the epicenter (this together with depth will determine how far seismic waves have had to travel to reach your location and generally waves attenuate with distance), [seismic site effects](_URL_3_) and the [directivity](_URL_7_) of the earthquake rupture with respect to the location. Generally (if we were standing on the epicenter so depth = distance from the [hypocenter](_URL_5_)) we could say that as depth increases or magnitude decreases, the perceived intensity of the earthquake at a point on the surface will decrease, but given the variability and the importance of the details for any particular rupture, there is no unique answer as to which one would be the larger determinant. Anecdotally, I would probably argue that depth has a potentially larger importance given the huge depth range over which earthquakes can occur. For example, this [M 8.2, 600 km deep earthquake](_URL_4_) was [barely felt](_URL_6_) where as this [M 8.2, 47 km deep earthquake](_URL_8_) was [widely felt](_URL_0_) and indeed [killed 78 people](_URL_2_). The 600 km deep earthquake is definitely an anomaly (we don't see too many earthquakes that deep, let alone that big at that depth), but it illustrates that extreme depth can really attenuate shaking felt at the surface. | [
"In seismology, the depth of focus or focal depth refers to the depth at which an earthquake occurs. Earthquakes occurring at a depth of less than are classified as shallow-focus earthquakes, while those with a focal depth between and are commonly termed mid-focus or intermediate-depth earthquakes. In subduction zo... |
Baltic and North Seas meet but don't mix because of the differing density. Is a difference in density sufficient to cause immiscibility? | They may have a boundary like that but diffusion happens between the two bodies. It is not correct to think they wall each other off. Keep in mind that this is a surface picture only. | [
"The Baltic Sea's salinity is much lower than that of ocean water (which averages 3.5%), as a result of abundant freshwater runoff from the surrounding land (rivers, streams and alike), combined with the shallowness of the sea itself; runoff contributes roughly one-fortieth its total volume per year, as the volume ... |
how does pi contain every word or combination of words? | This is a common misconception.
Pi is an irrational number. Irrational numbers are numbers that can't be expressed as a quotient of two whole numbers. One minor property of irrational numbers is that when you try to write them as decimal fractions, you get an infinite and non-repeating sequence of digits.
There are a lot more irrational numbers, for example e (euler's constant), the square roots of 2, 3, 5 (and every other number that isn't a whole square) and many others - in fact, there are more irrational numbers than rationals.
A special subset of irrationals are *normal* numbers. In the decimal expansion of a normal number, sequences of digits are distributed uniformly - so for example every possible digit appears about 1/10th of the times, and every possible pair of digits appears 1/100th of the times, etc. (it's a bit more complex, but lets leave it at that). In a normal number, every possible combination of digits appears somewhere. Since we can use numbers to encode letters (a=1, b=2, c=3...) you can say that a normal number contains every possible word or phrase.
Here's an example for a normal number: 0.12345678910111213141516171819202122.....99100101102103104.....
Pi is hypothesized to be a normal number, however it is yet to be proven. Not every irrational number is normal - for example, the number 0.101001000100001000001000000... is obviously infinite and not repeating (hence it is irrational), but it doesn't contain the digits 2-9. | [
"Mnemonic phrases or poems can be used to encode numeric sequences by various methods, one common one is to create a new phrase in which the number of letters in each word represents the according digit of pi. For example, the first 15 digits of the mathematical constant pi (3.14159265358979) can be encoded as \"No... |
how can someone with a peanut allergy develop a semi-immunity to peanuts? | Immunotherapy has been applied to many allergies, yes.
There's two general competing mechanisms that drive allergy.
The first is what you could call the "pro atopic" side. This is the allergic response, and in these types of allergies it is mediated by a class of antibody called IgE. To simplify it a lot, more IgE against the allergen = more allergic response.
The second is the regulatory side. The regulatory side is what inhibits the allergic response and reduces IgE levels. This is mediated, in part, by a class of antibody called IgG4. Also very simplified, more IgG4 against the allergen = less allergic response.
We know that some factors favor an IgE response. These are: later exposure in life, intermittent exposure, high dose exposure.
We know some factors favor an IgG4 response / lower IgE response: earlier exposure in life, consistent exposure, low dose exposure.
Immunotherapy works by giving you a low dose, consistent exposure to the allergen to build up a regulatory response.
It's been proven to work in a lot of clinical trials for many common allergies, but work is still ongoing. Part of the trick is that you have to do the immunotherapy just right, or the allergy may just get worse. The best preventive measure, though, seems to be exposure to the allergen before 1-2-years-old (based on other trials). | [
"Peanut allergy is a type of food allergy to peanuts. It is different from tree nut allergies. Physical symptoms of allergic reaction can include itchiness, hives, swelling, eczema, sneezing, asthma, abdominal pain, drop in blood pressure, diarrhea, and cardiac arrest. Anaphylaxis may occur.\n",
"The clinical tri... |
why after staring for too long into a light source (i.e. the traffic light), that pattern gets burned onto our sight? | Im no expert but I think this is because the cones/rods which sense light in our eyes "adapt" when exposed to light and become less activated so when you look away it takes some time to adapt again and you see a negative of that image for a while afterwards | [
"Some witnesses describe the light as appearing to approach them several times before retreating. Others report that the lights were able to keep pace with them when they were in a moving motor vehicle.\n",
"A 1972 article in the \"Wilmington Star-News\" argued that \"most investigators\" had believed the light w... |
Recycling of International Space Station? | To move anything from Earth orbit to Lunar orbit, you need about three times its mass as propellant. To do that for the entire space station, that would mean about 1,350,000 kg of propellant. To get all that to low Earth orbit, would mean about 11 Saturn V launches, or double that for Falcon Heavy.
As to why small pieces of it couldn't be reused, I'm not sure. If it has a module that would be perfect for a Moon/Mars mission then it would certainly save in fuel costs to have it in orbit already. Most likely has to do with engineering issues, how to separate the right module from the station, then dock it with your space craft and so on. But I wouldn't completely rule out the possibility that something like that might be done.
Edit: Also the space station has a constant upkeep cost. You can't just leave it there and at some later point pick modules out of it when you need them. You need to keep boosting its orbit periodically. Just one of those reboosting missions might as well instead take a new better module to orbit for your other mission to use. | [
"The crew continued the task of building and enhancing the International Space Station by delivering the U.S. Destiny Laboratory Module. It was the first NASA lab to be permanently used ever since the days of Skylab nearly three decades earlier. It was manufactured by Boeing at the Michoud Assembly Facility and the... |
how are the red blood cells separated from your blood during platelet donation? | If you want to separate something like blood that's made of water and different types of cells, you put it in a *centrifuge*, which is a machine that simply spins a hollow drum with test tubes in it ***really, really*** fast. As you spin the drum, the red stuff is forced to the bottom of the tube since it's heaviest, then you have the “buffy coat” on top of that, which has platelets and protein bits, and the top layer is the plasma. | [
"Donated blood is usually subjected to processing after it is collected, to make it suitable for use in specific patient populations. Collected blood is then separated into blood components by centrifugation: red blood cells, plasma, platelets, albumin protein, clotting factor concentrates, cryoprecipitate, fibrino... |
why are things cheaper in the countryside? | MUCH cheaper land. Other things may be less expensive (like fruit and meat if you're in a farming area), and some things may be more expensive (like electricity, internet access, and utilities). However, anything you're buying locally has to have a store, and for most stores, rent and property taxes is one of their largest expenses. Rent and property taxes are FAR lower in the country than in the city. This means less overhead and so stores can charge less and still profit. | [
"Smaller communities have fewer choices in food retailers. Resident small grocers struggle to be profitable partly due to low sales numbers, which make it difficult to meet wholesale food suppliers' minimum purchasing requirements. The lack of competition and sales volume can result in higher food costs. For exampl... |
Accessible Viking Primary Sources | So the problem with the "from the Viking's perspective" part is that they were pre-literate during much if what we call the "Viking Age" (c.800-c. 1050). All of the sources from this time period are thus written by Anglo-Saxons, Franks, Arabs, etc. The sagas and later stuff are all pretty far removed from the period of most activity.
For documents from this period, you can check out [Viking Sources in Translation](_URL_0_) for an online source-book.
There are a few documents which may be especially useful to you:
The [Account of Ohthere and Wulfstan](_URL_1_) is an interesting source. It comes from an Anglo-Saxon translation of Orosius' *Historiae Adversus Paganos* but the Anglo-Saxion "author" added two brief accounts by two Norse captains about their voyages. They are short and they are probably the closest we have to an actual first person account.
The [Vita Anskarii](_URL_3_) is a saint's life of the so-called Apostle to the North, Anskar, written shortly after his death by his pupil Rimbert. It is super Christian and long and boring for the most part But there are a few interesting tidbits in there about life in Scandinavia. See esp. chapters 10, 19, 27, and 30. Anyway a quick skim might locate some stuff for your students.
The [Rök Stone](_URL_2_) is an *actual* viking "document" and you might be able with a bit of searching to find more rune stone transcriptions online.
In terms of sagas and later work someone else can hopefully answer that, as they fall outside of my time period and I don't have them immediately off my head. I'll think a bit more and see if I can find/think of anything useful. | [
"Modern scholars consider \"Cogad Gáedel re Gallaib\" to be a piece of \"brilliant propaganda\" written in a \"bombastic style and full of patriotic hyperbole.\" Although the chronicle remains a valuable source of information about the Viking Age in Ireland, its accuracy is uncertain.\n",
"Information about the V... |
can the shape of earbuds damage your ears/hearing. | It could if you decide to jam something that does not fit into your ear. Imagine a ten centimeter diameter hole in piece of paper, now imagine trying to fit a 20cm diameter rod through that same hole, it's going to rip the hole if forced through. TLDR: one size does not fit all and its up to the user to realise this and act on it accordingly. | [
"Dysfunction of the three small bones of the middle ear – malleus, incus, and stapes – may cause conductive hearing loss. The mobility of the ossicles may be impaired for different reasons including a boney disorder of the ossicles called otosclerosis and disruption of the ossicular chain due to trauma, infection o... |
Why do our mouths fill with saliva right before we vomit? | To protect your teeth from stomach acid, which essentially turns your enamel into gum. This is also why you shouldn't brush your teeth directly after, and not at all if you don't have fluoride mouthwash to use prior to brushing. | [
"Saliva contains digestive enzymes called amylase, and lingual lipase, secreted by the salivary glands and serous glands on the tongue. The enzymes start to break down the food in the mouth. Chewing, in which the food is mixed with saliva, begins the mechanical process of digestion. This produces a bolus which can ... |
why do i still need the disk for ps3 games after it's 'installed'? | Because it's not the entire game being installed.
Some games have a pre-install to store information on your PS3 so loading times in-game will be kept to a minimum. If they were installing the entire game to your PS3's hard drive then you would run out of space after the first game. | [
"The Linux Kit turns the PlayStation 2 into a full-fledged computer system, but it does not allow for use of the DVD-ROM drive except to read PS1 and PS2 discs due to piracy concerns by Sony. Although the HDD included with the Linux Kit is not compatible with PlayStation 2 games, reformatting the HDD with the utili... |
if a "double-yolk" egg was fertilized, would it, hypothetically, hatch 2 chiclets? what about a triple-yolk? | It depends on if there was a bird embryo on each yolk. The babby chicken is the little white (or red) goopy wisp thing you see on the yolk. The yolk is just the chick's food supply. | [
"In normal monozygotic twin development, one egg is fertilized by a single sperm. The egg will then completely split into two, normally at the two-cell stage. If the egg splits in the early blastocyst stage, two inner cell masses will be present, eventually leading to the twins sharing the same chorion and placenta... |
can dogs understand other dogs when they bark? | Dogs don't bark in a language like how you speak English. Languages are an invention which must be taught to our children and requires constant care and revision to be mutually intelligible. Dog barks are extremely simple vocalizations. Though it is probable that dogs have a better idea of why another dog is barking than your average human, that doesn't mean that there's any content for the dog to "understand". Dogs don't bark to communicate with each other in sentences, they are merely vocalizations that are indicative of aroused emotional states. | [
"Stanley Coren identifies 56 signals which untrained dogs make and people can understand, including 10 barks, 5 growls, 8 other vocalizations, 11 tail signals, 5 ear and eye positions, 5 mouth signals and 12 body positions. Faragó et al. describe research that humans can accurately categorize barks from unseen dogs... |
what was the purpose of the holocaust? why did hitler want to kill millions of people, and how did he select the ethnic/minority groups? | He saw the "Aryan" race as superior, which was essentially Caucasian and strictly not Jewish. He wanted to wipe out all "undesirables". This didn't entail Jews alone. He sought to wipe out Roma and Sinti people, homosexuals, political enemies such as communists, and only wanted chosen individuals within the Aryan race to breed. Someone could probably add more to the minorities he sought to wipe out.
Edit: Also consider that Anti-Semitism was prominent long before Nazi-Germany, so it wasn't exactly difficult for him to persuade the masses into following the regime. | [
"The military campaign to remove certain classes of persons (above all, Jews) from Germany and other German-held territories during World War II, often with extreme brutality, is known as the Holocaust. It was carried out primarily by German forces and collaborators, German and non-German. Early in the war, million... |
Why can a rocket fly straight up without wings and doesn't tip over? | Large commercial rockets are actively steered. Either the engines are 'gimbaled' (the angle is adjusted) constantly, or small sideways-pointed rockets are fired as needed, to push the rocket where the computer is programmed to send it.
Smaller rockets without adjustable engines or controls normally cause the rocket to spin as it flies, so any off-angle forces are canceled out. Doing this without fins is tricky, which is why smaller rockets generally do have fins. | [
"Another problem in this maneuver is that higher lift from the faster moving outside wing will roll the airplane to the left (or to the right). Most pilots find holding forward right (or left) stick necessary throughout the pivot.\n",
"If the engine kept pushing the nose straight up even as the rest of the rocket... |
Were the German bunkers on Omaha beach much further from the shire than popularly dramatised in thr film Saving Private Ryan? | One of the historical 'inaccuracies' about Saving Private Ryan is that the film does shorten the beach considerably. Omaha Beach has a very shallow slope and the distance between the low tide and high tide marks can be as much as 400-500m. The landings were timed to start at low tide in order that the various beach obstacles would be exposed. This would both allow the obstacles to be avoided and for the engineers to blow them in order to clear lanes for the follow on waves.
However this meant that the assault waves had a considerable amount of open beach to cross before reaching even the limited cover of the shingle line just above the high tide mark. The German gunner Heinrich Severloh notes that after the troops left their boats he had to wait a while for them to reach the 400m mark which was his range for opening fire. The film fails here by showing German gunners firing down on US troops emerging from boats at what seems to be just 100-200m away. In reality the firing angle would have been much shallower.
Very few, if any, US troops attempted to fight from the open beach. To do so was suicide. Instead they re-grouped and began reducing the defenses from the shingle and rocks at the bottom of the bluffs. In this respect the film does a decent job of showing how the fight went. The bunkers themselves were very close to the high water mark.
Primary source : Joe Balkoski, *Omaha Beach*
| [
"Midway between the old harbour and the camping ground an old German bunker, constructed around the time of World War I, appears on the beach. During World War I, it formed part of \"Sicherungsstellung Nord\", a German line of 900 bunkers spanning the region of Sønderjylland, constructed to halt an eventual English... |
how does an automated check-out tell the difference between the different notes (eg: £5, £10, £20) and different coins? how does it tell these from regular paper (notes) or items of a similar shape/weight (coins)? | _URL_0_
Notes are scanned and matched up to images stored in the software, which also checks for some security features. If you produce a sufficiently good fake, it will be accepted, but it would be easier to pass it to a human.
Coins fall into slots which are the correct sizes. The slots have valves which only open if the coin is the correct weight. For example see _URL_1_ Some coins are magnetic and this is also tested. Any object which doesn't fall into a valid slot will come out into the reject tray.
Coins are made of specific proportions of metals and it is hard to make something which is the same size and weight, unless you use the same materials. Therefore the main way to obtain something that would be accepted as a coin would be another coin from a different country, as there are only so many possible sizes and shapes. This is why the Thai 10-baht used to be accepted as 2-euros in Eurozone vending machines until the owners started realising they were getting scammed, then they upgraded their machines to tell these coins apart. | [
"Electronic counting systems, with no moving parts, exist that count both notes and coins on the same machine and sum the value of all denominations counted. They are normally used to count individual deposits or the content of cash drawers and do not sort or check for counterfeit or damaged notes.The machine uses ... |
Has any other ancient civilization/Empire other than from India come up with the Philosophy of Nonviolence? | Gandhi's own belief in non-violence was strongly influenced by Leo Tolstoy's, expressed in his book *The Kingdom of God is Within You*, whose pacifism is credited to his religious views as a Christian. Tolstoy wrote in *A Confession, The Gospels in Brief, and What I Believe*:
> The passage which served me as key to the whole was Matthew, v. 38, 39: "Ye have heard that it was said, An eye for an eye and a tooth for a tooth: But I say unto you, Resist not him that is evil" ... These words suddenly appeared to me as something quite new, as if I had never read them before. Previously when reading that passage I had always, by some strange blindness, omitted the words, "But I say unto you, Resist not him that is evil", just as if those words had not been there, or as if they had no definite meaning.
> Subsequently, in my talks with many and many Christians familiar with the Gospels, I often had occasion to note the same blindness as to those words. No one remembered them, and often when speaking about that passage Christians referred to the Gospels to verify the fact that the words were really there. '
Gandhi was quite receptive to Tolstoy's book, and praised it by writing:
> Tolstoy's *The Kingdom of God is Within You* overwhelmed me. It left an abiding impression on me. Before the independent thinking, profound morality, and the truthfulness of this book, all the books given me by Mr. Coates seemed to pale into insignificant
Pacifist philosophy did exist as a movement within Christianity, with Tolstoy being its most famous advocate. Pacifism was also present in pre-Buddhist Chinese philosophy, but someone more knowledgeable on that topic will have to elaborate on it. | [
"The political philosophy most closely associated with modern India is the one of ahimsa (non-violence) and Satyagraha, popularised by Mahatma Gandhi during the Indian struggle for independence. In turn it influenced the later movements for independence and civil rights, especially those led by Martin Luther King, ... |
Why is the ethnic majority of China referred to as "Han Chinese"? | You're right in thinking that the Han was a dynasty of China. It lasted from 206BCE to 220CE, and was an incredibly important dynasty in Chinese history in terms of scientific, cultural and political developments. Think of it as the Classical Chinese period.
The reason that we talk about 'Han Chinese' is because of the Han Dynasty's prominence in international and so people began to call themselves '漢人' (hànrén), 'The People of Han'.
Some groups of Southern Han peoples use a different phrase however, '唐人' (tángcháo) which means 'People of Tan' in reference to the later Tan Dynasty (618-907CE) which was another very important Dynasty. | [
"11 - 92% of the Chinese believe that they are of one race, the Han Chinese, unlike the other most populous nations such as India, the United States, Brazil, Indonesia and Turkey which recognize themselves to be highly multi-racial and multi-cultural\n",
"Han Chinese people, the largest ethnic group in China, are... |
Hi Reddit! How fast can the effects of gravity be felt? I don't really know how to word this, check out the text for further description. | Gravitational waves would travel at the speed of light, so we'd move normally for about eight minutes. | [
"Critical response for Professor Heinz Wolff's Gravity has generally been lukewarm, receiving an overall score of 63 on Metacritic. The website IGN awarded it 59 out of 100, citing it had potential to be a sleeper hit, but was too light on content for the price tag.\n",
"The effects for negative g-force can be mo... |
Does covering your mouth when you sneeze/cough actually help prevent the spread of disease? | Yes it does; [while not the best scientific source, a good visual representation](_URL_0_) | [
"Prevention is by not smoking and avoiding other lung irritants. Frequent hand washing and flu vaccination may also be protective. Treatment of acute bronchitis typically involves rest, paracetamol (acetaminophen), and NSAIDs to help with the fever. Cough medicine has little support for its use and is not recommend... |
Why did we have to send a probe to Pluto to get a photo of it? | The photo of the black hole is not a "photo" in the sense you are thinking. It is a visualization of very high-frequency radio waves. While these are still electromagnetic waves just like visible light, they are way outside of our visible range. This is necessary to "penetrate" through all of the super-heated matter that surrounds the black hole. In the visible spectrum, all we would see is a big ball of light ([_URL_0_](_URL_0_)).
Pluto does not emit radio waves on the scale of a supermassive black hole (if at all), so we cannot get a similar image. | [
"In July 2015 NASA published photographs taken as the New Horizons space probe passed within 7000 miles of Pluto. A photo of Pluto's largest moon, Charon, shows a large dark area near its north pole. The dark area has been unofficially called Mordor Macula.\n",
"On February 12, 2015, NASA released new images of P... |
how do programs like ccleaner clean the windows registry? | Registry cleaners are pretty much useless these days, as Windows is pretty good about keeping the registry clean itself. Regardless, cleaning the registry doesn't really result in much of a performance impact.
One of the big things that registry cleaning does is remove entries that refer to files/folders that no longer exist. Poor software uninstallers do not remove all of the programs registry entries, that's the biggest contributor to unnecessary registry data. | [
"Most Windows applications still store their user settings in individual .ini (initialization) files spread across the disk. They additionally use the Windows Registry to store information which might be of interest for other software. For such programs the Windows Registry acts rather as a bulletin board, than as ... |
I've just read a very short article about Old French Sign Language. What we do know of deaf life, culture and community in 18th century Paris? How was deafness depicted in general in France in this period? | Do you have a link to the article? | [
"In France, the first sign languages developed in the 18th century. Old French Sign Language was used in Paris' deaf community, before l'Abbé Charles Michel de l'Épée started his deaf school in 1760 in Paris. L'Épée's lessons were based upon his observations of deaf people signing with hands in the streets of Paris... |
Someone told me it was "too cold to snow". How? | The amount of moisture in the air is dependent upon its temperature, below a certain point there is too little moisture for precipitation.
There are various large stretches of the Antarctic that qualify as deserts because they have so little precipitation due to this principle. But -2 is certainly warm enough to snow.
Can anyone put a name to this principle? | [
"After a successful trial with Norwegian club Bodø/Glimt he joined them on initially on loan in 2012. Having moved from Senegal to the Arctic Circle, Ndiaye admitted it was a culture shock.—\"When I got up on the first day and opened the front door I was terrified. I had never seen snow before, or at least only on ... |
what keeps movies unreleased? what stops any movie studio employee from just downloading a movie that hasn’t come out and leaking it to the internet? | Because theft and distribution are crimes. People aren't keen on having their lives ruined to show off some movie. | [
"\"There are websites that provide legal downloads. This is not one of them. This website has been permanently shut down by court order because it facilitates the illegal downloading of copyrighted motion pictures. The illegal downloading of motion pictures robs thousands of honest, hard-working people of their liv... |
how is it that the mars curiosity rover is able to go years without fuel/recharging and how are we able to send such a strong signal? | Curiosity, the MSL rover that was successfully landed in Gale Crater on August 6, 2012, uses one MMRTG to supply heat and electricity for its components and science instruments. Reliable power from the MMRTG will allow it to operate for several years.
In February 20, 2015, a NASA official reported that there is enough plutonium available to NASA to fuel three more MMRTG like the one used by the Curiosity rover. One is already committed to the Mars 2020 rover. The other two have not been assigned to any specific mission or program, and could be available by late 2021.
_URL_0_ | [
"When fully illuminated, the rover triplejunction solar arrays generate about 140 watts for up to four hours per Martian day (sol). The rover needs about 100 watts to drive. Its power system includes two rechargeable lithium ion batteries weighing each, that provide energy when the sun is not shining, especially at... |
We all hear about species being extinct. But how often does a new species "evolve" into a new one? | [This article](_URL_0_) (PDF) seems to put it at about 3 new species per year but it is very debatable. Speciation may occur in burst and there are many other factors. Hopefully someone else can dig up more information. | [
"If a population cannot move or change sufficiently to preserve its long-term viability, then obviously, it will become extinct, at least in that locale. The species may or may not survive in other locales. Species extinction occurs when the death rate over the entire species exceeds the birth rate for a long enoug... |
why do i get sleepy when i get nervous? | You might have some kind of chemical imbalance, disease, or infection. You should get that checked out. There isn't really an ELI5 answer to this. | [
"Seriously anxious people find it difficult to control their worry and typically experience symptoms like Restlessness, Fatigue, Difficulty in concentrating, Irritability, Muscle tension and Sleep disturbance.\n",
"According to the American Academy of Sleep Medicine there is a wide range of potential causes, incl... |
how come chinese words in english are spelled funky? | Zhou is not pronounced like Joe. Chinese words are generally spelled according to their pinyin (phonetic system) which has correlates English letters to pronunciation. | [
"Foreign words, mainly proper nouns, continue to enter the Chinese language by transcription according to their pronunciations. This is done by employing Chinese characters with similar pronunciations. For example, \"Israel\" becomes \"Yǐsèliè\", \"Paris\" becomes \"Bālí\". A rather small number of direct translite... |
During the California gold rush why didn't the American government at the time leave it for other immigrants | The gold of the California gold fields - as it was understood in 1849 and the early 1850s - was an extensive resource, meaning that it was broadly distributed in small amounts. It took tens of thousands of people to process hundreds of thousands of tons of dirt to find the gold they were seeking, and at that, $4 - roughly a quarter of an ounce - was considered a good day.
The General Government (as the US federal government was known) did not have the resources - human or otherwise - to work the gold fields and process all that material. Most miners were only making a living wage to do the work and very few people ended up with surplus wealth. If the government had nationalized the gold fields, which is what you're suggesting, it would have had to pay all those workers, and it would not likely have profited much.
By the mid 1850s, California miners were seeking underground "intensive" gold deposits in the form of gold veins. These were concentrated, but their retrieval required a great deal of technology and supplies as well as skilled labor. Again, the government could have nationalized the mines, but it would have been a tremendous challenge to harness the people and to find the money to invest in a highly speculative, risky undertaking. It was best left to the private sector to shoulder the cost and to take the risk.
Because of all this, the national mining acts of 1866 and then, 1872, outline an approach to mineral resources, particularly on federally managed land. Because the risk of failure was so great, the federal law basically offers the resource to anyone who can find it and develop it. The perceived common good was in the mineral wealth being pumped into the economy and in the development of remote locations in North America. Although there have been many attempts to amend the generous aspects of the 1872 Mining Law, it remains the statute that governs mining to this day: it has not been possible to built a consensus around any alternative. | [
"In January 1848, two weeks after California was ceded to the United States, gold was discovered in California, resulting in a flood of fortune seekers gravitating to the state in the following months and years. Due to the ambiguity of existing laws regarding squatting on federal land, individual mining camps devel... |
Were there any European explorers prior to 1700 who attempted to cross the pacific ocean from Asia? | If you are asking if Europeans had been crossing the Pacific before 1741, the answer is a ***clear yes***. Magellan's expedition in 1519-1522 was the first to cross the Pacific in from east to west direction, going from Magellan's straits to Phillipines. And it was followed up by many more till 1741
If you are asking if other Europeans had been crossing the Pacific in a specifically from west to east direction - from Asia to Americas - prior to 1741, the answer is ***also a clear yes***. In the follow up to Magellan's voyage, Spanish sent numerous expeditions to try to establish a commercial route from Americas to Asia, with the problem being that contrary winds prevented an easy return to American continent.
It wasn't until 1565 when following the conquest of Philippines by Miguel López de Legazpi, ships under Alonso de Arellano and Andrés de Urdaneta returned to America by first going north to 38th parallel where they found (as they had expected to find) winds blowing in the eastern direction which they used to steer the ships back to America. Sadly I do not know enough information about the expedition to go into more details, but suffice to say the ships headed from the Philippines, steered north to 38th parallel, then changed course due east, reaching first California and then heading south to Mexico where Spanish settlements were to be found. The discovery of this route was then been immediately taken advantage of by the Spanish. For the next several centuries, pretty much every year several ships were crossing the Pacific from Acapulco to Manila and then back, carrying New World's silver to be exchanged for Far Eastern goods. A system which is nowadays most commonly referred to as "Manila Galleons" and on which plenty of literature exists.
So the answer is that without any doubt, Europeans were regularly crossing the Pacific from Asia for almost two centuries before 1741. The reference you quote, of a Russian ship being the "first Europeans to arrive in Northwestern North America" can then only be considered serious if we limit the scope to just Northwestern North America (whatever that means) and definitely not implying they were the first to go from Asia to Americas | [
"In 1519, an expedition sent by the Spanish Crown to find a way to Asia was led by the experienced Portuguese navigator Ferdinand Magellan. The fleet explored the rivers and bays as it charted the South American coast until it found a way to the Pacific Ocean through the Strait of Magellan.\n",
"In the second hal... |
How important was the Act of Union (1707) to the growth of the already existing English empire? Would England itself have had a comparable empire in size to the British Empire had it not formed the Kingdom of Great Britain with Scotland? | This question would be better suited to /r/HistoricalWhatIf | [
"In 1707, the Acts of Union received their Royal assent, thereby abolishing the Kingdom of England and the Kingdom of Scotland and their respective parliaments to create a unified Kingdom of Great Britain with a single Parliament of Great Britain. Anne formally became the first occupant of the unified British thron... |
what can someone do if they have your ip address? can they see all your internet activity and places you've posted? can they identify who you are? | If they *only* had your actual IP address, they could DDOS you and potentially locate you within a rough geographic area. But that's about it.
If they had your IP but also purchased or collected date from cookies and such, they could learn a lot more. | [
"In 2010 the Federal Supreme Court of Switzerland found that IP addresses are personal information and that under Swiss privacy laws they may not be used to track Internet usage without the knowledge of the individuals involved.\n",
"Finding \"relevant\" and \"reachable\" IP addresses is the objective of the reco... |
why does 'latin' mean hispanic? | Likewise, Hispanic means you're from Hispania, or Spain. It doesn't really make sense to call someone from say, Venezula an Hispanic, even if they speak Spanish. That's like saying someone from Minnesota is English.
Regardless, Hispanic is still used that way. | [
"Though often used interchangeably in American English, \"Hispanic\" and \"Latino\" are not identical terms, and in certain contexts the choice between them can be significant. \"Hispanic\", from the Latin word for \"Spain,\" has the broader reference, potentially encompassing all Spanish-speaking peoples in both h... |
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