q_id
stringlengths 5
6
| title
stringlengths 3
301
| selftext
stringlengths 0
39.2k
| document
stringclasses 1
value | subreddit
stringclasses 3
values | url
stringlengths 4
132
| answers
dict | title_urls
list | selftext_urls
list | answers_urls
list |
|---|---|---|---|---|---|---|---|---|---|
9sjzh0
|
what's the difference between delirium and psychosis?
|
From what I could find they look very similar. What are the differences?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9sjzh0/eli5_whats_the_difference_between_delirium_and/
|
{
"a_id": [
"e8pgn84"
],
"score": [
3
],
"text": [
"In the most basic sense, delirium is caused an underlying medical/physical illness or problem. \nWhen the underlying problem is treated, delirium is resolved. \n\nPsychosis is a symptom of a mental illness like during a manic episode or more commonly in schizophrenia. Antipsychotic meds help to control these symptoms. "
]
}
|
[] |
[] |
[
[]
] |
|
101tdh
|
how do 47% of people in the us not pay federal income tax?
|
Is 47% of the population below the poverty line? Does that number include children and other ineligible-for-work demographics? I'm so confused.
Thanks for keeping your responses civil : )
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/101tdh/how_do_47_of_people_in_the_us_not_pay_federal/
|
{
"a_id": [
"c69n6t1",
"c69nc29",
"c69sfn3",
"c69y5vr"
],
"score": [
6,
50,
21,
2
],
"text": [
"The majority of households in the US make under $45k a year. The government offers pretty significant tax deductions to families, and it just doesn't take that many deductions to cover the entire income tax burden when you're making that amount of money.",
"There are a few groups of people who don't pay federal income tax. \n\nThe biggest group (about 60% of them) don't because they qualify for enough deductions to reduce their burden to $0 (think lower-class families with kids). Both parties are responsible for introducing tax cuts/credits, so if this is in response to Mitt Romney's leaked video, it's a bit of a stretch to blame it on Obama and the Democrats (in fact, the biggest jumps in non-taxpayers happened under Reagan and Bush II). With that said, they do pay payroll taxes, for things like Social Security.\n\nAlmost a quarter are elderly and retired.\n\nAbout 15% are the under-the-poverty-line types.",
"Here is an ELI5 answer:\n\nWhen you have a job and earn money, that money is totaled up at the end of the year and compared against the amount of tax taken out of your paychecks throughout the year. At this same time, the IRS says that you can subtract money from the amount you earned depending on different things:\n\n- If you have kids, you can take away $$$ per kid\n- If you own a house, you can take away $$$ for the interest on your mortgage\n- If you work from home you can take away $$$ for your expenses like electricity and office supplies\n- If you donated to charity you can take away $$$ for that\n\nOn top of this, each person also gets a standard deduction, meaning you can take $$$ right off the bat, but a lot of times you can either do the standard deduction OR the items from the list above. This is called itemizing. \n\nSo, imagine if you owned a house, and had 3 kids, but only made $30,000 last year. Your standard deduction (that everyone gets) might bring your earnings down from $30,000 to $20,000. Then, for each kid lets say you can take away $5,000 more (3x$5000=$15,000). That means you have $5,000 in earnings left that can be taxed. Finally, you paid $5,000 in intrerest in your home for that year, so you take away $5,000 from your earnings.\n\nJust like that, you now made $0 taxable dollars as far as the IRS is concerned. This means you don't owe any taxes, and any taxes you did pay throughout the year will get returned to you.",
"That statistic is kind of a stretch. However, John Green wrote a really [great blog post about it that breaks it down.](_URL_0_)\n\nIts well worth reading and sharing. Basically, there's no one reason. Some people are just flat poor, others have lots of deductions, some people re-invest their money in their business, and other people (like many on Reddit) are full time students."
]
}
|
[] |
[] |
[
[],
[],
[],
[
"http://fishingboatproceeds.tumblr.com/post/31770870662/who-doesnt-pay-taxes-and-why"
]
] |
|
1z4ye5
|
What was the role of Druids in Pagan Irish religion?
|
I've been looking into it for a research assignment and a lot of the stuff's pretty sketchy. I just was interested in some information about it.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1z4ye5/what_was_the_role_of_druids_in_pagan_irish/
|
{
"a_id": [
"cfqtl0b"
],
"score": [
4
],
"text": [
"Our information about the druids are pretty scarce because the druids themselves didn't keep any records. What knowledge we have are from the Romans, who usually portray them as some sort of priests (divine powers, contact with the Gods, etc.). This quote is from Tacitus (book XIV, chapter 30) in the Annals:\n\n > On the shore stood the opposing army with its dense array of armed > warriors, while between the ranks dashed women, in black attire like > the Furies, with hair dishevelled, waving brands. All around, the \n > Druids, lifting up their hands to heaven, and pouring forth dreadful \n > imprecations, scared our soldiers by the unfamiliar sight, so that, as > if their limbs were paralysed, they stood motionless, and exposed to > wounds. Then urged by their general's appeals and mutual \n > encouragements not to quail before a troop of frenzied women, they > bore the standards onwards, smote down all resistance, and \n > wrapped the foe in the flames of his own brands. A force was next \n > set over the conquered, and their groves, devoted to inhuman \n > superstitions, were destroyed. They deemed it indeed a duty to \n > cover their altars with the blood of captives and to consult their \n > deities through human entrails.\n\nAs you can see, the druids were thought to have some sort of power that made the enemies weak and after their defeat the Romans simply burned the druids' grooves (sort of their 'temples'), which may be why we don't have any information about them.\nPerhaps I should clarify about the quote as well. The last few lines about covering the alters in blood and consult their deities through human entrails are describing the Romans, not the druids.\n\nAnd if someone can explain to me how to format a quote that long without getting random arrows in the middle of the lines (which it seems I need to make it a quote), I would be most grateful."
]
}
|
[] |
[] |
[
[]
] |
|
3dsxjb
|
the miller-urey experiment
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3dsxjb/eli5_the_millerurey_experiment/
|
{
"a_id": [
"ct8c84d"
],
"score": [
14
],
"text": [
"Scientists were trying to determine if the chemicals needed for life (amino acids) could be produced from the chemicals that they believed existed when the Earth was young.\n\nSo, they took those chemicals and put them in a closed loop along with water. They heated that water to simulate evaporation from the oceans and zapped the air with electricity to simulate lightning strikes.\n\nIn the end, they found well over 20 amino acids were created, many of which are the fundamental building blocks of organic life.\n\nSo, this experiment shows that it is possible to create organic chemicals from inorganic sources."
]
}
|
[] |
[] |
[
[]
] |
||
3ei4ct
|
can you think of ancient (more than 500 years ago) monarchs who may have had Autism? If "yes" who were they and what were they like as a ruler?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3ei4ct/can_you_think_of_ancient_more_than_500_years_ago/
|
{
"a_id": [
"ctfjm0y",
"ctfkim3",
"ctfsgyx"
],
"score": [
19,
47,
6
],
"text": [
"Karl XII of Sweden, though not ancient, could be considered autistic. He was celibate and disliked alcohol, and many of his peers noted his lack of emotion and his extreme tolerance to pain. \n\nAs a ruler, Karl XII was focused entirely on war, specifically the Great Northern War against Russia. His losses against Russia led to the dismantling of royal autocracy for a parliamentary monarchy. He went into exile in the Ottoman Empire, where, after constant scheming, he was forced to escape to Norway, where he died in battle.\n\nEdit: Fixed some errors on my part. ",
"This sort of retrospective diagnosis of some sort of condition ought to remain nothing more than speculation.",
"I don't think you're going to get a historically sound answer to this question. Autism is hard enough to diagnose today when we know what to look out for. It's going to be even harder when the only information we can get access to is speculative at best based on the understanding of even obvious illnesses. We can look at rulers and guess what may have been the underlying cause of decisions and choices, but when it really comes down to it we can't see their responses to people directly (eye contact, emotion, social skills). \n\nSince this sub requires sources and a certain level of certainty with answers you might find people more willing to speculate about this question in another less strict sub. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
6kfyya
|
do breathalyzers measure bac accurately for people with lung issues such as asthma, copd, or just being generally out of shape?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6kfyya/eli5_do_breathalyzers_measure_bac_accurately_for/
|
{
"a_id": [
"djlphio"
],
"score": [
4
],
"text": [
"Breathalyzers are \"good estimates\", not highly accurate. They don't measure total breath flow, either. They just determine the percentage of alcohol in the C02 of your breath, and conditions like asthma, COPD, or others don't really have any affect on that.\n\nIf you're on the verge of blowing just at the legal limit, you can contest the findings of a breathalyzer test by providing urinalysis, which is highly accurate. They can then work backwards using simple math to find your BAC at any given point in time.\n"
]
}
|
[] |
[] |
[
[]
] |
||
13hd3v
|
Nazism: Left, Center, Right? Or something different entirely?
|
My major in college is History (mostly European) and Political Science. Over the past 4 years many of the courses I have taken at one point or another have touched or focused on Fascism and Nazism (one of the courses I took was entirely on the topic of Nazism by Political Philosopher Stephen Bronner). One thing that has fascinated me is the attempt to place 20th century fascism somewhere on the left, center or right of the political sphere both as an ideology and as a political theory.
The gist of that I have learned is more complicated than saying Nazism simply resides on the extreme right. Nazi fascism in a historical context does not uniformly fit on the right (empire/monarchy) or the left (marxism/unions/socialism), due to its state centric goals and opposition to both communism and the empire as it existed before Weimar. Largely the similarities to the left and the right can be attributed to the NDSAP and Hitlers attempt to lure people on the left and right by any means and ultimately appealing to what we would call the center (moderates/independents). They did this while simultaneously rejected the core principles and philosophies of both sides and instead promoted a new theory that promoted the state over the masses or the individual.
What do you guys think? Where would you place Nazism?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/13hd3v/nazism_left_center_right_or_something_different/
|
{
"a_id": [
"c740wmv",
"c741vru",
"c74223m",
"c7428gj",
"c742pjy"
],
"score": [
10,
2,
3,
2,
6
],
"text": [
"The [Left/Right](_URL_0_) model is a broken paradigm that isn't particularly useful for classifying political parties. I know everyone (including myself) uses it, but it's a bad habit.\n\nThe weaknesses of the model are especially highlighted when you try and classify extreme groups like the Nazis. Gun to my head I would classify them as 'far-right', not because they necessarily have a lot in common with center-right parties, but because that is the general consensus and doing otherwise just leads to needless confusion.",
" > the right (empire/monarchy)\n\nWhile this was the conception of the \"right\" that existed at the creation of the left-right political spectrum in the wake of the French Revolution, the spectrum, even in its severe limitations, has evolved to the point where the right does not exclusively or even primarily represent the \"*Ancien Régime*\" anymore.\n\nI find it helpful, when using the left-right political axis, to pair it with an intersecting authoritarian-libertarian axis, in which fascism would be roughly right-authoritarian, anarchism left-libertarian, and so on.",
"The nazis were definitely on the right, but they were rather unorthodox fascists. Fascism was explicitly envisioned initially as a third way movement, and has a long history of adherents on both the left (peron, Naser, arguably mussolini) and the right (franco, salazar)",
"I would argue that they are economically leftist (state controlled economy and emphasis on socialism) and socially rightest (traditional roles, patriotism and militarism).",
"This is not a good paradigm and most people will use Nazism on this spectrum to tar their opponents and justify their own viewpoints. There is a lot of baggage to this topic and its almost always used in the context of current politics. You can try debating this in an academic setting, but its almost impossible to disentangle the paradigm from contemporary political debate. "
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Left%E2%80%93right_politics"
],
[],
[],
[],
[]
] |
|
2sb2ca
|
Is water cycle present in Antarctica?
|
I was wondering, as Antarctica does not often experience temperatures above zero degrees Celsius, if snow just accumulates or if there is a water cycle present on the continent
|
askscience
|
http://www.reddit.com/r/askscience/comments/2sb2ca/is_water_cycle_present_in_antarctica/
|
{
"a_id": [
"cnntdpe"
],
"score": [
5
],
"text": [
"Sure there is a water cycle, it's just a bit different than the other continents. Snowfall is driven by winds carrying moisture in from the oceans. Water molecules can return from the ice to the atmosphere via sublimation, which is like evaporation but is a phase change directly from the solid (ice) to gas (water vapor) phase. The other key term in the water cycle is the loss of water to the ocean via the glaciers that slowly carry the ice into the sea. So a rough budget for the antarctic ice sheet is:\n\n(snow fall) - (sublimation) - (glacial flow into sea) = (change in mass of ice over time). "
]
}
|
[] |
[] |
[
[]
] |
|
1ajnkn
|
I do not understand why different zygotes from the same parents are different and not clones.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ajnkn/i_do_not_understand_why_different_zygotes_from/
|
{
"a_id": [
"c8y0q7z",
"c8y0zec"
],
"score": [
8,
3
],
"text": [
"Each parent contributed only one of each of their chromosome pair to the zygote. For each chromosome, one of the two is picked at random. In humans that means that you have 2^23 (or about 8 million) possible sets of chromosomes from each parent for the zygote to inherit. This alone makes it unlikely for two zygotes to be identical, even given the same parents. [Chromosomal crossover](_URL_0_) makes it even less likely.",
"I believe you're asking, essentially, why siblings aren't genetically identical. A \"normal\" cell is diploid, and has two sets of each chromosome. A gamete, or sex cell, contributes half of the genetic material to the zygote, and is thus haploid - it has half the genetic material. There's no way to tell exactly which half will be divided into the gamete, and because there are 23 sets of chromosomes, there are a huge number of possible combinations. There are two properties at work here - the law of independent assortment, which essentially says that the division of one chromosome set doesn't affect another, and crossing over, which forms a hybrid of the set of chromosomes and adds additional diversity."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Chromosomal_crossover"
],
[]
] |
||
2i3i86
|
so, given that people use quantum physics normally and also talk about how it involves observation or whatever, how has this fact been proven?
|
Or perhaps that wording is incorrect.
I recently got a quick little explanation about quantum physics from vsauce, and they talked about how things are actually random in Quantum Physics, and measured in probabilities. That the thing is actually decided upon observation (Sleepy, can't remember exactly what was said). I might want an explanation of Q.P. itself sometime, but right now I'm curious as to what evidence exists that confirms this, to the point that it actually appears to be common knowledge (based on a few forays onto the internet).
How can there be proof that something is decided only upon observation, when it's impossible (or, at least, apparently paradoxical) to observe this happening? What evidence supports something like this?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2i3i86/eli5_so_given_that_people_use_quantum_physics/
|
{
"a_id": [
"ckygk6c",
"ckyhk01"
],
"score": [
2,
3
],
"text": [
"Look up 'the double slit experiment'. It explains how light behaves as a wave and a particle .\n\nBasically if fire photons one at a time through slits onto a background, where the photons land should eventually form two slits on the background (two slits, two lines right?). Well, it doesn't. It creates multiple lines.\n\nThis is because the photon is acting as a wave and travelling trhough both slits at the same time, when they exit the slits the waves interfere creating an interference pattern. If you throw a pebble on to a lake it makes waves extending outwards. If you through another pebble at the same time it's waves will interfere with the others, creating intersection points.\n\nThe photons wave intersect causing the wave to collapse into a particle, producing multiple lines on the background. This is known as an interference pattern. But we had one photon fired from the emitter! The photon has landed in multiple places at the same time! This is quantum super-position and Heisenberg uncertainty principle in action, we don't know anything about the particles position or momentum until it lands on the background.\n\nNow, if we put a detector in between the background and the slits, the photons are detected by the emitter and the wave collapses immediately into a single photon and the lines on the card represent two slits exactly.\n\nBy observing the photon via a detector before it has chance to reach the background we force it to become a particle.",
" > \"*the thing is actually decided upon observation*\"\n\nThis is the most common way of describing it, but it trips people up because it implies the necessity of an observer.\n\n\"observation\" in the quantum-mechanical context simply means that the system in question has come into causal contact with another, different quantum system. A human scientist, or their photon detector, is a quantum-mechanical system.\n\nWhen that happens, the two systems may be, for some length of time, in a state that requires a definite outcome rather than a probabilistic range of *possible* outcomes. As soon as the systems become separated again and no longer require a definite result, things (we presume) return to their more fuzzy state.\n\nAs mentioned by /u/CptCreosote , the double-slit experiment is an excellent example of the proof required. In fact, it was having this experiment shown for me in a darkened high school physics classroom using nothing but a sheet of cardboard and a cheap laser pointer that convinced me of the validity of the whole scientific method.\n\nBut if that's not good enough, you very probably have working proof for quantum mechanics in your own pocket right now: your phone.\n\nThe [touch screens](_URL_0_) on modern smartphones rely on a quantum-mechanical phenomenon called \"tunnelling\" to work, which is a product of the fact that the precise location of a given particle (in this case, an electron) is indeterminate until some event causes it to become determined (in this case, the pressure of your finger).\n\nThe microprocessors in that phone are also proof - the same tunnelling phenomenon is one of the major remaining obstacles in modern microcircuitry design because once your circuits are small enough and the track width is narrow enough, they can wind up with electrons tunnelling from one pathway to another, causing signals to arrive where they shouldn't and resulting in incorrect outcomes from the input provided. \n\nWe also exploit quantum mechanics in the construction of atomic clocks, without which my phone's GPS wouldn't work because none of the satellites would remain synchronized.\n\nFinally, the transistors which are at the heart of any computer, no matter how old or crude, rely on quantum mechanics to work.\n\nQuantum Mechanics is well beyond the realm of theory at this point. Sure, things like pointing a laser (*which itself exploits quantum mechanics in order to work*) at a couple of slits in a darkened classroom makes for a compelling (and beautiful) demonstration, but for my money the really conclusive proof is that there is a little device in my pocket that was designed from the ground up to exploit quantum uncertainty, and that this is considered a normal part of daily life. \n\nI'd say it's pretty solidly established to be completely real at this point.\n\n**TLDR**: Your smartphone is proof of quantum mechanics."
]
}
|
[] |
[] |
[
[],
[
"http://www.sixtysymbols.com/videos/touchscreens.htm"
]
] |
|
9uz958
|
(Biology) why do people get red in the face when lifting/moving heavy objects?
|
askscience
|
https://www.reddit.com/r/askscience/comments/9uz958/biology_why_do_people_get_red_in_the_face_when/
|
{
"a_id": [
"e99kfhe"
],
"score": [
9
],
"text": [
"Basically, if you're lifting something heavy your muscles will need to be supplied with more oxygen and waste products like lactic acid (from anaerobic respiration) will need to be taken away from the site through your blood.\n\nThis increased blood flow causes your blood vessels to dialate, bringing blood closer to the surface of your skin, making your face red."
]
}
|
[] |
[] |
[
[]
] |
||
53u00u
|
what makes ram volatile and hdd's and other memory devices like that non volatile?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/53u00u/eli5what_makes_ram_volatile_and_hdds_and_other/
|
{
"a_id": [
"d7w7m9t"
],
"score": [
4
],
"text": [
"Fundamentally, it's about the way the memory is constructed. Volatile memory requires a constant source of power to maintain its storage, whereas non-volatile memory doesn't.\n\nDRAM (which is the RAM you're thinking of) is made of capacitors that are charged up if they're storing a 1 bit. It's very small and simple, but capacitors always leak charge, even if they're not connected to anything. Thus, if you don't constantly refresh them, then all the 1s will have their charge drain out and the data is lost. Without power, that refreshing can't happen, so it loses whatever it's storing within a very short amount of time (generally a couple hundred milliseconds) once the power goes out.\n\nHard drives, on the other hand, store data by magnetizing a physical disc of material. The magnetic properties of the material don't change as long as a magnet doesn't come by and mess it up, so you can safely remove the power and then power it back up later and read it again."
]
}
|
[] |
[] |
[
[]
] |
||
1o5b0m
|
why someone with half a brain can live? will he lose something from the surgery?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1o5b0m/eli5why_someone_with_half_a_brain_can_live_will/
|
{
"a_id": [
"ccows1z",
"ccowuti"
],
"score": [
3,
2
],
"text": [
"We just did this in my psych class actually so here goes.\n\nHalf the brain is only actually removed in young children, because their brain is still developing, it adapts to only having half of it there so the person learns to function almost normally.\n\n[Here is a video about a girl who had half her brain removed to prevent seizures.](_URL_0_)\n\nWith adults they do not remove half the brain, they just sever the connection between the two halves. Both halves of the brain are still functional, they just can't communicate. This leads to the person having \"two minds\", although they are only conscious of one of them. Some interesting stuff happens with that, for example, a man was aware of things he saw with his left eye but couldn't name them, but when asked to draw what he saw he could do it with his left hand. He did not know why he drew these things, but it was the correct image.\n\nedit: [Here is the video I was describing about the guy with the disconnected brain. The bit I described starts at 1:20.](_URL_1_)",
"Depending on how much of the brain is removed, someone can live with much less than half of a brain. Depending on the sections of brain they will lose, they can also lose, sight, muscle control, memories, spacial reasoning, timing, and all sorts of other weird things that the brain controls. \n\n_URL_0_\n\nCheck out this lady, the Wikipedia article is very light for her amazing abilities. She had a kiwi sized chunk of her brain removed to fix an issue with seizures. Since she has become the worlds most elite distance runner. She lost the ability of spacial reasoning and time. She can sleep for an hour and feel like she has slept all night. She can run for hours and not feel tired, because she doesn't know how long she has been running. Really a remarkable story. "
]
}
|
[] |
[] |
[
[
"http://www.youtube.com/watch?v=2MKNsI5CWoU",
"http://www.youtube.com/watch?v=ZMLzP1VCANo"
],
[
"http://en.wikipedia.org/wiki/Diane_Van_Deren"
]
] |
||
qetq5
|
Is a bacteriophage just a virus that infects bacteria?
|
With my general background in biology, I understand that phages (bacteriophages) were just viruses that infect bacteria. Are phages really related to viruses such as those that infect animals or other nucleated cells, or are phages just "phages" that happen to infect bacteria?
Was I just taught that phages were virus for simplicity? How do we actually classify phages and/or viruses
|
askscience
|
http://www.reddit.com/r/askscience/comments/qetq5/is_a_bacteriophage_just_a_virus_that_infects/
|
{
"a_id": [
"c3x2i9e",
"c3x3nzk"
],
"score": [
4,
3
],
"text": [
"Phage is short for bacteriophage, which is a virus that infects bacteria (there are many types of bacteriophages). There are also viruses that infect other types of organisms like animals; these are not bacteriophages.\n\nAs to a question like \"Are bacteriophages related to animal viruses?\" or something like that, I believe this is unknown. We only have a few decades worth of sequenced virus genomes. There are no (or very little) virus fossils or preserved virus genomic material like there is for some extinct animals like dinosaurs for example (as far as I know). There may be common virus ancestors but it is hard to form a very convincing opinion based on such little data.\n\nEdit: Also, virus genome and protein sequence is incredible divergent. Where we see well conserved genes in lesser eukaryotes like yeast all the way up to humans, this conservation is not nearly as prevalent in viruses. I believe we only see related virus genes within virus families or orders.",
" > Was I just taught that phages were virus for simplicity?\n\nNo, a phage is a virus and Phage is a term to indicate that it afflicts Procaryotes.\n\n > How do we actually classify phages and/or viruses\n\nSince a Virus isn't really a living thing and doesn't do much outside another organism, you classify viruses by those organisms and what they do to them. The systematics follow the ones we have for living beings.\n\nEdit: Read what the guys under me talk about. They are smarter then I am. ^^"
]
}
|
[] |
[] |
[
[],
[]
] |
|
4uwe63
|
why are their age restrictions in american public offices?
|
Say if I was 25 or even 30 I wouldn't be able to run for President, or if I was 18 I couldn't run for Congress? Why is that?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4uwe63/eli5_why_are_their_age_restrictions_in_american/
|
{
"a_id": [
"d5tf14g"
],
"score": [
6
],
"text": [
"It mostly has to do with what the constitution says. For president you have to be at least 35 years old as it was thought you would have enough life experience and wisdom to lead the country. :) "
]
}
|
[] |
[] |
[
[]
] |
|
51vvo1
|
Augustus' political affiliation? (Populares/Optimates)
|
What was Augustus' political bias?
Did his status as Princeps make him officially impartial in the Senate?
I would have thought his relationship with Caesar would make him "Populares"
Ave!
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/51vvo1/augustus_political_affiliation_popularesoptimates/
|
{
"a_id": [
"d7fjdt6"
],
"score": [
6
],
"text": [
"That's simply not how Roman politics worked. *Populares* and *optimates* were not political parties, factions, or affiliations. The *optimates* in particular don't really exist--*optimas*, and the more common *bonus* is a rhetorical term that is applied to pretty much whomever you want to apply it to at the given moment. It carries a baggage of class rather than status, and even then one can be included in the *boni* without being in the senatorial class--Cicero includes the *equites* in the category all the time and in many of his speeches the *plebs* are included in the category, so that one wonders who exactly *isn't* considered one of the *boni*. That the *optimates* are not indicative of a political mindset becomes immediately obvious. Cicero condemned repeatedly the indecision and constant internecine bickering about trivial matters that so absorbed the *nobiles*, whom he famously called privately *piscinarii*, \"fish-fanciers.\" Nor was *popularis* indicative of a political affiliation. A *popularis* was simply a politician who prioritized the power of the citizen assemblies over the political support of the senate. A politician could put on a *popularis* hat without having any previous record of populist actions, and could take it off again immediately--in fact this was the norm, even Cato did it during his tribunate. The *popularis* hat might even be worn in cases where the politician was trying to support something seemed decidedly unpopulist--Cicero depicted himself as a *popularis* when he shot down the Rullan agrarian bill (and as far as the urban poor was concerned he was probably acting in their interest--generally the rural plebs supported agrarian bills and the urban plebs opposed them and supported colonial foundations). Even Gaius Gracchus, supposedly one of the first *populares*, passed legislation weakening the powers of the tribunate and was quite staunchly aristocratic. Roman politics had no expectation that a politician stick to a consistent platform--the very idea of platforms would have been totally alien--and it had no expectation that a politician place himself in a \"conservative\" or \"progressive\" camp, provided that such terms would even make sense to a Roman (they probably wouldn't). For more on this see [this](_URL_1_) thread, and probably [this](_URL_0_) one.\n\nSuffice to say that the inability to categorize Augustus meet the same difficulties. He was a Caesarian, but that means almost as little as calling him a *popularis*--Antony was also a Caesarian. Antony shows how difficult the label *popularis* is. Antony was frequently accused of being a rabble-rouser, most notably when he started the riots at Caesar's funeral. But during his proconsular governorship of Italy Antony famously opposed the demagogue Dolabella, nearly causing mass rioting in the city and forcing Caesar to return prematurely to fix things up--a decidedly un-populist move. If we expect *populares* to support \"populist\" legislation (which I think we've seen we should absolutely not) then both Caesar's dictatorship and Augustus' entire career are hard to place. Both reduced the distributions of public grain (and Augustus made them essentially hereditary, and the privilege of a particular sub-class), both apparently abolished voluntary associations like the *collegia*. Neither were popular in their treatment of Italian land--Caesar's decemvirate was notoriously unpopular (and in 59 he and Pompey were booed in the theater) and Octavian took most of the blame for the bloody land distributions of the proscriptions, which benefited neither the urban nor rural plebs, only the Caesarian veterans. Octavian, while holding tribunician power, essentially did away with the tribunate and eventually with free elections in general, though a pretense was made until after his death. But simultaneously Octavian and Caesar were said to employ the power of the citizen voting body, or in Octavian's case the army, over the aristocracy--in 59 Caesar ignored the senatorial review (not in itself a crime, but certainly looked down on, and traditionally an action that got one labeled a *popularis*) and took his agrarian bill directly to the assemblies. One should not look for consistent *popularis* or...whatever the opposite of that would be (optimate simply doesn't cut it) action in a politician, because with all but no examples there was never any consistent action of that sort, nor was there an expectation of it"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/410g4i/were_there_established_political_factions_in_the/",
"https://www.reddit.com/r/AskHistorians/comments/358ic9/did_the_ancient_athens_or_the_roman_republic_have/"
]
] |
|
641sb3
|
why are residential solar panels common, but not wind turbines? or water wheels for people who live by rivers?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/641sb3/eli5_why_are_residential_solar_panels_common_but/
|
{
"a_id": [
"dfyprk3",
"dfypvza",
"dfyq73s",
"dg1tf36"
],
"score": [
2,
3,
3,
2
],
"text": [
"Because solar panels are small and compact, compared to giant turbines and water wheels that have a tendency to be as big as the house itself. ",
"Wind turbines are all about size, bigger is more economic, not more (edit: not more of them. If a manufacturer/operator could choose, they would pick bigger size over quantity), so they're not cost effective in a subdivision. They also make a lot of noise, require quite a bit of maintenance, and space, kill birds, and are unsightly (for those who care). You can't expect homeowners to keep up on the maintenance of their own turbines, so you have to build a far less efficient model that at least won't explode in a catastrophic failure, sending blades sailing and impaling people or property.\n\nI don't think there are enough people who live along rivers to make this a viable market for a manufacturer. I think they'd be more interested in hydro turbines instead of old fashioned water wheels, but that requires building dams, which have a huge environmental impact and we're doing what we can to tear down small, privately held dams, not build more of them.",
"You can buy them, but they are usually quite expensive. After all, they need to be durable in order to run for years. But the real problem is that ground level wind is a lot weaker than at the altitude that real wind turbines are positioned, so you're not getting a lot of power. I've only ever seen them being used on boats, running the fridge and other low power devices. ",
"Micro-wind turbines (under 1.5kW) are notoriously bad at producing a reasonable amount of energy to make them economically viable. Indeed, some probably consume more energy than they produce.\n\nThis is mostly down to the size (too small), the mounting height (too low, wind blows faster at greater heights) and poor wind regime (urban areas have too many obstacles that disrupt wind flow)"
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
1egsbe
|
How many different colors were categorized/can be distinguished by an average human?
|
I'm wondering how many different shades of colors we are able to distinguish from each other just by perception? How can we explain the difference from 'color-concepts' to 'color-branding' (giving a specific shade a name)?
I know about the Pantone-scale but I'm most of all interested in how many shades are actually differentiable?
Thank you!
|
askscience
|
http://www.reddit.com/r/askscience/comments/1egsbe/how_many_different_colors_were_categorizedcan_be/
|
{
"a_id": [
"ca0fdm8"
],
"score": [
2
],
"text": [
"This article answers your question and provides an interesting extension in the form of tetrachromats _URL_0_"
]
}
|
[] |
[] |
[
[
"http://www.digitaljournal.com/article/326976"
]
] |
|
61cd6g
|
"nuking" the filibuster
|
I get the gist (changing the rules from requiring 60 votes to requiring a simply majority), but I've heard it can only be done at the beginning of a new term. Is this true, or can it be done at any point?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/61cd6g/eli5_nuking_the_filibuster/
|
{
"a_id": [
"dfdg8u7",
"dfdievm"
],
"score": [
5,
2
],
"text": [
"It can be done at any time. The Senate Majority Leader would declare Senate Rule 22(filibuster rule) a Constitutional question, and the Senate would immediately begin debating Rule 22 with a simple majority needed to change the rule.",
"It can be done at anytime. The filibuster is just a Senate procedure (they have 100's of them) and a simple majority can change any Senate procedures. So they can essentially change it at any time they want.\n\nThe reason it has not been changed, and probably will not, is because both political parties know without it the minority party has a lot less power. And at some point in the future they *will* be the minority power. \n\nBack in 2009 there was a lot of talk about the Democrats getting rid of filibusters to pass the ACA. They chose not to. If they had chosen to get rid of it, they would have had more power back then, but have almost no power now. Likewise, the Republicans also know at some point in the future they will not be the ones in power. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
abm8tk
|
when you shake flour, why do all the larger bits make their way to top and not the bottom?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/abm8tk/eli5_when_you_shake_flour_why_do_all_the_larger/
|
{
"a_id": [
"ed1d0ce",
"ed1ktie"
],
"score": [
5,
2
],
"text": [
"You can do the same experiment with a jar of rocks. Shaking the jar allows all of the little rocks to find their way down in the spaces between the larger rocks. Keep shaking and pretty soon all of the big rocks will appear to \"climb\" to the top.",
"Basically because the small bits go to the bottom.\n\nStarting out, all the big and small bits are randomly mixed. When you shake them, there is an opportunity for things to fall into a more efficient spot.\n\nSo, all the flour (sand, nuts, whatever...) is momentarily separated a tiny space; what bits will be able to fall? Big bits or small bits?\n\nThe small bits are able to fall into the small gaps created by shaking, so the small bits all go to the bottom and the larger bits eventually make their way to the top."
]
}
|
[] |
[] |
[
[],
[]
] |
||
ofiac
|
Why should I wash my hands after using the restroom? Bear with me here...
|
So, imagine that a male wakes up in the morning, showers thoroughly, gets dressed and goes on about his day. His hands interact with the world: Touching doorknobs, surfaces, other people, etc.
Upon entering a restroom to urinate, throughout the whole day the penis has remained shielded from the outside world and is still, presumably, about as clean as it was after a good washing. Perhaps a small bit of sweat may have been produced, depending on the weather and/or activity of the male.
Now, it seems to me that when this male enters the restroom, he should wash his hands BEFORE urinating in order to keep germs and such out of a perfectly clean area. And he should wash off his penis after touching it with hands that have been exposed to a variety of microbes.
Now, I realize that washing hands after using the restroom is a good idea considering toilet seats, the surfaces that can be touched, etc. But, in the scenario of urination only, what is the potential for transporting harmful microbes without washing the hands?
|
askscience
|
http://www.reddit.com/r/askscience/comments/ofiac/why_should_i_wash_my_hands_after_using_the/
|
{
"a_id": [
"c3gtf0f",
"c3gtx3q",
"c3gu5du",
"c3gugvn"
],
"score": [
7,
5,
2,
2
],
"text": [
"Your skin is always covered with various types of bacteria. The pelvic (specifically genitoanal) region, is typically populated by a class of bacteria known as [coliforms](_URL_0_), which are generally harmless when on the skin or in the normal environment in the intestines, but can cause illness if introduced elsewhere. \n\nSimple washing alone won't get rid of these bacteria, as they are actually in your skin at a microscopic level and are constantly being replenished from other pelvic areas. They can still be transferred to your hands by touching or aerosolization. Short of autoclaving yourself from navel to knee, you're better off washing your hands post-piss.",
"Urination will cause aerosols as well. This will allow bacteria from the urinal or toilet to deposit on your hands as well as allowing the bacteria from your urethra to transfer to skin surfaces. Not to mention the door/flusher you may contact as well in process of getting there. Also keep in mind that we don't typically wash our hands in between getting a cup of coffe and doing paperwork etc. all day, but those are all covered in bacteria as well, and so, it happens to be a very convenient time to wash off the days additions to our flora.",
"I finally have something to contribute to this subreddit.\n\nThe point of washing your hands after using a bathroom isn't to just clean off germs from the process, but also to have a regular hand washing schedule. There are other sources of bacteria and junk that you accumulate during the day. However, it would be impractical to wash your hands every time you handle money or touch a staircase banister. \n\nBottom line is, if you aren't washing your hands after using the bathroom, then when are you?",
"I kind of agree with you, but I think there is a better rationale.\n\nMicrobiota naturally live on the skin that compete with pathogenic bacteria, and the skin also produces various antimicrobial peptides that generally keep bacteria in check. They live on the penis, on the hands, just about everywhere, so washing hands before touching the penis is probably superfluous. Also, urine itself is sterile. For these reasons, and also because I have to wash my hands a lot in the lab, I do not typically wash my hands after urinating. However, I always wash my hands post-defecation, as feces is a common and powerful means of transferring pathogenic material.\n\nThat being said, before eating with my fingers I like to wash my hands with a mild, non-antibacterial soap, under the assumption that there are people who do not wash their hands after pooping, and have spread fecal material to things I have touched. These bacteria can make it through the acidic environment in the stomach and cause problems if they are pathogenic.\n\nThe routes of pathogen transfer I am most concerned about are coughing, sneezing, and vomiting in crowded areas, which can all aerosolize harmful bugs"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Coliform_bacteria"
],
[],
[],
[]
] |
|
3dmxww
|
why do we die instantly when our heart stops? why don't we asphyxiate from lack of oxygen from blood no longer circulating?
|
I know this sounds extremely dumb but I've always wondered about this. I can understand dying via shock if shot or stabbed in the heart. But when it just stops because of old age or sickness, why is death instant? They say you can live about 5 minutes without oxygen so why don't we die after about 5 minutes since blood is no longer circulating?
Like I said, I know this sounds really dumb because it's basically like "well because your heart stopped, duh!". But why does it stopping kill you instantly instead of brain death through suffocation?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3dmxww/eli5_why_do_we_die_instantly_when_our_heart_stops/
|
{
"a_id": [
"ct6ori6",
"ct6oua7",
"ct6p8li",
"ct6pm5x",
"ct6ui4z",
"ct6wors",
"ct6xm0g",
"ct6xyzr",
"ct6ywbb",
"ct72gvn",
"ct745or",
"ct7gez8",
"ct7gidk"
],
"score": [
426,
8,
2,
42,
7,
2,
2,
2,
6,
3,
3,
4,
2
],
"text": [
"You don't die instantly; people with a totally stopped heart often die, but it is possible if the heart resumes in a timely manner you'll survive.\n\nThere's a distinction between alive and conscious, though. A total stop in blood flow will make you pass out really quickly; in fact a sudden decrease in blood flow to the brain can easily cause one to faint even without the heart stopping.",
"Even if you are not breathing, there is still oxygen in your body that your heart circulates. Enough for about 5 minutes. When it stops, your brain is not receiving the oxygen it needs anymore and you die.",
"Why do you think you die instantly? If that's a concept brought to you by Hollywood, bear in mind that they are more interested in (and familiar with) dramatic effect than physical science.\n\nThat being said, you'd die *quickly.*",
"As u/terrkerr pointed out, when your heart stops beating you quickly lose consciousness but do not die immediately - that's why CPR sometimes works.\n\n\nYour brain can survive without adequate blood flow for about five minutes before ireversible damage occurs and you become a vegetable, even if your heart is artificially restarted and the rest of your body is ticking away - that's how we get brain-dead organ donors.\n\n\nThe reason your brain is so sensitive to lack of blood flow is because as well as oxygen, blood contains all the other nutrients that circle around your body. One of these is glucose (sugar). Other organs can survive a little while by switching to a different form of respiration but the brain cells only eat glucose. They are also very active cells and go through glucose at a very fast rate. Hence if the supply stops even for a little while, they quickly die.\n\nEdit to add: death often isn't instant in old age or sickness, but people lose consciousness before they die so sometimes it looks like they die in their sleep or that they are dead when in fact they're just on the way out. \n\nHollywood paints a slightly confusing picture of death- if you believe the films, people are talking completely coherently, shut their eyes and game over.. In reality, It's sometimes difficult to tell and there's a whole protocol that doctors go through before they are allowed call someone dead, which involves checking for a pulse, breathing and eye changes. \n",
"So this is all about perfusion. \n\n\nYour brain has no stores of anything, so when your heart stops, glucose AND O2 cease to flow. Since your brain takes about 20% of total cardiac output, it tends to die quite quickly after the blood flow is shut off. After about 2-5 min of no O2(depending on the person) , the brain simply has suffered too much damage and won't come back without deficits, or at all.\n\nThat's what happens to you physiologically. What you'd feel is nothing. Your heart stops, count to 10, you slip into unconsciousness, and for all intents and purposes, you're dead there Capitan.",
"Wait, what? What makes you think we die the moment our heart stops beating? Did you see that in a movie or something?",
"It is the lack of oxygen (mainly to the brain) that kills you when your heart stops, so you don't die right away but you do lose consciousness pretty quickly. Your five minutes is pretty close.\n\nThere is a thing called the rule of threes (though it's only approximate): You can survive three minutes without oxygen, three days without water, and three weeks without food. This just a rule-of thumb, and is often broken by wide margins.\n\nSo when you hear that someone was brought back from the dead remember that just because their heart had stopped doesn't mean they were dead.",
"I was undergoing a series of tests at a hospital when my heart stopped for about 20 seconds. Didn't die. At least I'm pretty sure I'm still alive. Maybe I'm just a ghost and no one's told me... \n",
"As a nurse, we stop people's hearts in the hospital all the time. When you get shocked by a defibrillator, it actually stops your heart, not starts it. It starts back on its own.\n\nWe also give a medicine called adenosine that stops your heart. We do this for a number of reasons I won't go in to unless someone's curious. Anyway, it stops it for somewhere between 1 and 5 seconds. Once someone's took 7 seconds to come back, and let me tell you, that was a LONG 7 seconds.\n\nOpen heart surgery is another example. Your heart is paralyzed for hours during the surgery and a pump takes over. \n\nTL;DR : you don't, silly. Not if it starts again. ",
"The problem is defining what is 'dead'\n\nIf having no pulse is dead, then when your heart stops, you are by definition dead.\n\nThe definition of 'dead' has shifted as medical technology moves forward and our ability to resuscitate someone from the brink of death pushes the brink further and further out.\n\n[you are clinically dead](_URL_1_) when you are no longer breathing and your blood is no longer circulating. However, it is possible to revive someone at this point if you act quickly (~3 minutes before brain damage, which directly leads to brain death)\n\n[Brain death](_URL_0_) is what we would currently consider at as being really dead, because that is the point where the brain is damaged to the point it can no longer keep the body alive.\n\nProbably the only death that could be considered instantaneous would be one that destroys the brain instantly.",
"The biggest thing you should know is that when people say \"deoxygenated blood returns to the lungs to be reoxygenated\" they really mean barely LESS oxygenated blood returns to the lungs to be reoxygenated. I hate how this is worded in virtually all textbooks. \n\nThe blood returning to the lungs is usually only down to about 75% oxygen, while the blood leaving your heart has about 100% oxygen. \n\nIf you stop breathing but your heart keeps pumping blood to your brain, the oxygen content of your blood will decrease over time until you pass out. If your heart stops pumping, there will be no oxygen delivered to the brain and you die very quickly.",
"In 2006, I watched my dad die in the hospital. When his heart stopped, he suddenly started breathing really heavily which kickstarted his heart again. He would then stop breathing, and his heart would start beating really fast to kickstart his lungs. Then his heart would stop again and the cycle would start again. It went on like that for about an hour, even though he was dead.",
"You don't.\n\nWell, in the USA you do by definition, but for example in Europe the point of death is defined at the point in time, when your brain cancels out.\n\nThe problem is, that life and death are really not that horribly different as everyone always says.\nThere is simply no clear point when the Alive-LED stops shining..."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Brain_death",
"https://en.wikipedia.org/wiki/Clinical_death"
],
[],
[],
[]
] |
|
75o202
|
What is the historical significance of Dravidian history, their rule and culture? It looks like lot of their history is missing out?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/75o202/what_is_the_historical_significance_of_dravidian/
|
{
"a_id": [
"do81h9w"
],
"score": [
2
],
"text": [
"I might only be moderately qualified to answer this question, but for me (or anybody else) to do so would require a lot more information about what you're looking for in an answer. Could you narrow it down a bit?\n\nAs it is, you're asking a question about a culture group that sweeps literally all recorded history, from (possibly) the Indus Valley civilisation all the way to today's independent Indian state, along with huge questions of ethnic, linguistic, religious and national identity."
]
}
|
[] |
[] |
[
[]
] |
||
1dddzs
|
How does the amount of energy required to sustain a temperature vary with the temperature itself?
|
I was thinking about how much energy my air condition will use during the summer months and in particular how much energy goes into maintaining a set temperature. Suppose it is 100^° C outside (unrealistic I know but useful for understanding) and you set the thermostat at 80^° C. How much more energy (fraction/percent) would an air conditioner use to maintain 80^° C than say... 90^°C. Is there a formula or combination of formulas that would give this?. Assuming specific heat and other pertinent variables remain constant, one should be able to determine the ratio of energy used... correct? I assume there are aspects of q=mcΔT and Newton's law of cooling.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1dddzs/how_does_the_amount_of_energy_required_to_sustain/
|
{
"a_id": [
"c9p9xj1"
],
"score": [
7
],
"text": [
"Ignoring radiative heat transfer, the other main two routes for heat transfer are conduction and convection, both of which are proportional to the temperature gradient, and assuming a constant value for the latter say through a wall, proportional to the temperature difference, as you guessed. Now, assuming a steady state is reached, such that the heat removed by the air conditioner is equal to the rate of heat transfer from the outside, to a first approximation, it seems that there should be a linear dependence of the power required from the air conditioner as a function of ΔT."
]
}
|
[] |
[] |
[
[]
] |
|
8901ud
|
Was the Nazi's obsession with "wonder weapons" an extension of their ideology?
|
When the Nazis made expensive, hard-to-maintain tanks like the Tiger, was that an ideological decision or a secular mistake that any military could have made?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8901ud/was_the_nazis_obsession_with_wonder_weapons_an/
|
{
"a_id": [
"dwujesu"
],
"score": [
7
],
"text": [
"I'm not sure what would the ideological link be.\n\nBut about the reasoning of the Wunderwaffe.\n\nThe popular dichotomy between the triumph-of-will and triump-of-technology in warfare has been present in the Wehrmacht since the 1940, however not as it is commonly portrayed in popular culture.\n\nIn 1940, after the Battle of France, while the allies built their own propaganda myth of the countless german panzer divisions, Germany made certain propaganda materials focused on the technical and technological might of the French Army, specifically the Maginot Line, underlining the propaganda statement that advanced war technology meant nothing compared to the 'fierce german national spirit', thus effectively siding with the triumph-of-will side of the aforementioned dichotomy. An ideological link could be established here, that a german 'ubermensch' can achieve victory even over a better equipped opponent. This also has a cultural link we can trace all the way back to Beowulf, about a lone, strong, hero figure.\n\nHowever, as the aforementioned dichotomy is not false only in propaganda simplifications, and one shouldn't stick to it, Germans ( as well as Japanese, see IJN's decisive battle naval doctrine ) were well aware of the industrial capacity of US and Soviet Union, and were well aware that they couldn't outproduce them in standard weaponry, so they opted to focus on quality instead of quantity, to put it in layman's terms. \n\nGiven the temporal context where military technology was developing exponentially fast in all fields, instead, they invested their time and resources in hopes of gaining a technological edge, developing 'indestructible' and 'unsinkable' weapons, that they believed paired with the 'unbeatable' warrior ethos/mythos could win the war.\n\nSimply put, they didn't have much of an alternative. "
]
}
|
[] |
[] |
[
[]
] |
|
38hecu
|
the more i rub my eyes the more colors i see
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/38hecu/eli5the_more_i_rub_my_eyes_the_more_colors_i_see/
|
{
"a_id": [
"crv3rsi"
],
"score": [
6
],
"text": [
"When you rub your eye you are mechanically stimulating your retina, causing you to see light that is not actually there. The images projected by said light are called Phosphenes, specifically pressure phosphenes. It's you fooling your brain into believing photons are entering your eye when they really aren't."
]
}
|
[] |
[] |
[
[]
] |
||
6l55qg
|
difference of lcd, oled, and amoled that can be easily understood
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6l55qg/eli5_difference_of_lcd_oled_and_amoled_that_can/
|
{
"a_id": [
"djr8nce",
"djrdn6m"
],
"score": [
2,
3
],
"text": [
"LCD: Liquid Crystal Display.\nA flat panel display which uses light emitting properties of liquid crystals. These crystals are illuminated by a fluorescent backlight. \n\nSmartphone LCD panels are classified into two types - IPS (In-plane Switching) and TFT (Thin Film Transistor). IPS LCDs are usually seen on high-end smartphones and consume less battery than TFT. TFT displays are inexpensive but contribute to faster battery drain. LCDs offer better sunlight legibility and consume less power (only IPS panels) than AMOLEDs, but they lack the deep blacks offered by AMOLED panels.\n\nLED: Light Emitting Diode; OLED: Organic LED\nOLED displays contain an LED, which itself has an organic material that emits light when current is passed through. OLEDs exhibit deeper and darker blacks than vanilla LEDs.\n\nOLED displays are classified into two types- PMOLED (Passive Matrix OLED) and AMOLED (Active Matrix OLED). AMOLED adds a layer of semiconducting film behind the OLED panel which allows it to more quickly activate each pixel. AMOLEDs provide better picture quality than LCDs, have faster refresh rates, deeper black colour and most importantly, no limitation on the display size. The downsides of AMOLEDs as of now - they are generally more expensive to manufacture and incorporate into devices, they have poor readability in sunlight, and they eat up battery faster than LCDs. Most importantly, they are prone to image burn-in.\n\nThese issues are somewhat addressed by a variant of AMOLED called Super AMOLED. Although Super-AMOLED has been around for some time now, it's mostly installed on higher-end phones.",
"/u/kittuboy/ is correct about *LED, but made some mistakes about LCDs.\n\nLCD basics: structure with liquid crystals and polarizers that can be switched to pass light through or block it. Three such structures with RGB color filters and white backlight make one pixel. Because of constant white backlight LCDs are bad at producing deep black color.\n\nThere are several kinds of these structures. \n\n* TN, for twisted nematic, is cheap, but when you look at it from the side, colors are off — this is because its structure blocks light well in small angle only.\n* IPS, for in-plane switching, is more advanced, it can be viewed from any angle and generally have better colors, but it's more expensive. Also a few years ago it was considerably slower in switching from closed to open (from black to white), so IPS displays were not fit for videogames with lots of small fast changing details. They got better since.\n* PVA/MVA — were an alternative for IPS, a bit cheaper, a bit faster. Mostly went out of use when IPS improved.\n\nAlso, TFT is not an LCD type. It just means that there is a transistor for each pixel, unlike, say, in calculator's display. It means roughly the same as Active Matrix in AMOLED. So TN and IPS actually are TFT TN and TFT IPS.\n\nNow, *main* difference between LCDs and *LEDs is that first require backlight for the whole screen even if you need only one white pixel (and some light is leaking through even if scren is set to black), while second have pixels produce light themselves and powered off pixels are completely black. Guess difference in power consumption.\n\nThe only problem with *LED screens (aside of price) is that making good color filters for LCD is easier than making good color LEDs. Many consider AMOLED screen colors too vibrant and unnatural."
]
}
|
[] |
[] |
[
[],
[]
] |
||
65yhtm
|
why do you feel full faster if you eat slower?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/65yhtm/eli5_why_do_you_feel_full_faster_if_you_eat_slower/
|
{
"a_id": [
"dge5ofe"
],
"score": [
3
],
"text": [
"It takes some time for the chemicals responsible for fullness to be released and move from the stomach to the brain. When you eat slowly, these chemicals are released gradually and so your brain's levels of them rise gently. When you eat quickly, you suddenly shift from no fullness to tons of fullness, but it's delayed."
]
}
|
[] |
[] |
[
[]
] |
||
oumn5
|
How would 200 volts kill me (at 10 milliamps), but 200 amps (at 10 millivolts) not?
|
askscience
|
http://www.reddit.com/r/askscience/comments/oumn5/how_would_200_volts_kill_me_at_10_milliamps_but/
|
{
"a_id": [
"c3k5ua9",
"c3k60rq",
"c3k774v",
"c3k8ijr",
"c3ll2ny"
],
"score": [
30,
3,
13,
16,
2
],
"text": [
"First off, it's amps not volts that kills you; you have this backwards.\n\nAlso, your latter example gives you a resistance of 5 x 10^-5 Ohms, which is basically a conductor.",
"As someone mentioned you have some Ohm's laws problems up there. This leads to some problems in your question. A 10 mV supply would not be able to give a human 200 amps. This is due to skin resistance which is a few million ohms. Do Ohm's law on this and you can find the current, which would be outstandingly low. A 200 volt supply can start to push current through your body, a few mA. Therefore it would be effective. Get to higher voltages and your skin resistance breaks down and you just go through the body and get some serious current.\n\nOn to how you get hurt from electrcity:\n\nFrom my understanding from introductory physics classes, 60 mA is around the current that your heart takes to contract. If you put in 60 mA into your heart, you are feeding it a current it understands. This could stop your heart. 60 mA also is a current your muscles understand as well. I've been shocked by 240V AC for an extended period of time and have not be able to move muscle that had current flowing through them. \n\nAt a higher current your flesh starts burning; it overloads your entire body. Your heart does not recognize this level of current, and therefore does not respond to it. 200 Amps at the proper voltage would kill you a whole lot faster than 10 mA too. Instead of stopping your heart it would just cook you. You would look like a hotdog that had been on the grill too long.\n\nI hope this helps. By the way, the skin resistance on a human is a few million ohms.\n\n",
"Both currents can kill you - the difference is in how it kills you.\n\nA 10 milliamp current will most likely kill you through ventricular fibrillation, though it requires direct flow into the heart, via an electrode for example. \n\nA 200 amp current through your body will char you and burn you from the inside out.\n\nNote that I ignore given voltages - that is because they are unfeasible for the human body. The former case in your title would require roughly 20 times the measured electrical resistance in the human body, while the latter case requires the body to act as a near-perfect conductor.",
"It's amps, not volts, that hertz the most. ",
"Your example is a little off but let me explain it.\n\nWhile amps are primarily what you are worried about; amps itself can not kill you.\n\nLet's explain what the two actually are.\n\nVoltage is pressure; amperage is current.\n\nVoltage is the amount of pressure pushing the current through a circuit.\n\nAmperage is the amount of current being pushed through a circuit.\n\nWith an extremely low voltage; no matter the amperage; it can't be pushed accross your body to do harm. Likely with a high voltage and a low amperage while the voltage will push this amperage accross your body it may not be a high enough current to do damage.\n\nAs an electrician we use this every day. For the actualy power of a circuit it is defined as P(Watts) = Voltage * Amperage. We can freely manipulate the amount of voltage and current in a circuit to give us aspects favorable to the situation. Take for example amperage; if amperage is high then the conductor has to become larger as current causes a conductor to heat up. If voltage is high it does not cause a conductor to heat up; but due to pressure with a high voltage you have to worry about voltage jumping accross wires which require better insulation; and wires to be kept further apart. We have this nifty little thing called a transformer which can take voltage and amperage and move one up; and one down or vice versa. It moves up and down in comparison to the other. Which means the wattage or power of the circuit does not change. So say you wanted to push a large amount of power accross a small conductor; you could do that by making the voltage much higher, and in contrast the amperage would be low enough to not cause any issue with heat. We use this everyday in transmission; which is why we have high-voltage transmission lines to begin with. You will notice the large metalic towers that hold 120,000v per line; each conductor is kept very far away from every other conductor due to the voltage being used it can literally arc and jump accross conductors freely if they are to close. So we end up using high voltage lines to push the same power accross extremely small conductors. If we were to just use 120v and push it accross conductors everywhere; the conductors from a standard power plant would be required to be about a metre thick. Yet we transfer that power on conductors no more then 2 cm thick.\n\nSo getting back to everything; amperage is current which causes damage; however if the current is to low it will cause negligble effects. Voltage is pressure which pushes current accross a conductor(or you) but doesn't cause damage in on itself.\n\nThere are two types of electricity; AC and DC. AC standing for alternating current; where the electricity flows back and forth rapidly; in Canada it is doing this 60 times a second or 60 Hz. DC or direct current will move electricity accross a conductor. However which is more dangerous? Well it depends.\n\nAC is primarily more dangerous due to the way it interacts with the body. Take for example your resting heart rate; normally between 40-90 beats per minute. When running a current accross the heart vibrating back and forth at 60 times a second; which is very close to your resting heart rate it essentially causes your heart muscle to contract; and relax 60 times a second. This causes your heart to become erradic and stop due to fibrillation.\n\nDC while safer in some aspects to AC will kill you in an entirely different way. The current is constant; and does not allow your body to relax it's muscles; which means 2 things. You CAN NOT let go of a DC circuit; and it will continue; at least with high-current/high-voltage DC to essentially stop your heart dead; or cause your arms to melt off.\n\nAC is normally safer at higher voltage; while DC is normally safer at higher current."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
2qo0s7
|
the millennium prize problems
|
_URL_0_
One by one...nice and slow :)
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2qo0s7/eli5_the_millennium_prize_problems/
|
{
"a_id": [
"cn7wg3l",
"cn7ycxa"
],
"score": [
3,
2
],
"text": [
"Okay, i'm a CS guy so here you have **P vs NP**\n\nThis problem asks whether every problem whose solution can be quickly verified by a computer can also be quickly solved by a computer. (thanks [wikipedia](_URL_0_)).\n\nNow, like you were 5:\n\nJust imagine you have a box and a few keys and you are asked to find the key that opens the box. You try every key until you find the correct one, but this takes you a lot of time. You could verify that your key is the correct one very easyly, but to find this key isn't that simple. ( P is not NP )\n\nBut if you used some crazy NSA technology, you could look how the lock is and then just make a key that fits in that lock and opens the box. ( P = NP )\n\nIt is believed that P is not NP, but the problem is that you cannot **prove** it.",
"OKay let's try this with the **Birch and Swinnerton-Dyer Conjecture**. It's not the easiest to explain with simple words but let me try.\n\n\nThis is a conjecture about some particular curves, called elliptic curves. These curves are similar to one of [these drawings](_URL_0_). More precisely, an elliptic curve is the set of points (x,y) in the plane satisfying an equation of the type :\n\ny^(2)=x^(3)+ax+b\n\n\nSo imagine you get one of this curve, and then one asks if this curve goes through any *rational points*, namely points (x,y) on the curve where both x and y are rational number (like 3/5 or 11/27). Despite its apparent simplicity, this is a very difficult question. We have no general method of answering that, it depends on the specific curve we have : sometimes there are no rational points, sometimes there are just a bunch, sometimes there are an infinite number.\n\n\nWhat's interesting is that we know that for an elliptic curve with an infinite number of points, we can get all of them by only knowing a few of them, and finding the rest using just a ruler ! How to do it : you take two rational points on the curve, you draw the line between these two with your ruler, it will intersect the curve at a third point, and you take the symmetric of this third point. (see the left picture [here](_URL_1_)) and you get another rational point.\n\n\n\nOne question is \"What is the minimum number of points I need to have in the beginning to be able to get all the rational points with my ruler?\". This is called the *rank* of the elliptic curve and it changes from one curve to another. Computing the rank is, again, extremely difficult.\n\nThe conjecture says that we can compute the rank of a given elliptic curve by looking at a seemingly complicated object called the Hasse-Weil function. This is getting really difficult to explain with simple words so I will stop here ..."
]
}
|
[] |
[
"http://en.m.wikipedia.org/wiki/List_of_unsolved_problems_in_mathematics"
] |
[
[
"http://en.m.wikipedia.org/wiki/P_%3D_NP_problem"
],
[
"http://fr.wikipedia.org/wiki/Courbe_elliptique#mediaviewer/File:ECClines-3.svg",
"http://fr.wikipedia.org/wiki/Courbe_elliptique#mediaviewer/File:ECClines-2.svg"
]
] |
|
wyzhd
|
Humans are willing to sacrifice their needs/survival for people/things they love. In what other species is this tendency also seen?
|
And on a side note, are there actions of greed/murder in the natural world? I know there are some cannibalistic species, but I've never heard of let's say, psychopathic chimpanzees. It seems as though humans are the only species willing to compromise their survival for stuff (couldn't think of a better word).
|
askscience
|
http://www.reddit.com/r/askscience/comments/wyzhd/humans_are_willing_to_sacrifice_their/
|
{
"a_id": [
"c5hoz8y",
"c5hpg8u",
"c5hrsru"
],
"score": [
2,
4,
2
],
"text": [
"I'm not sure how analogous this would be to the concept of \"love\", but bees sacrifice their lives to protect the queen/hive.",
"This can be seen in a few species, though it may not be for \"love,\" depending on your definition of that word.\n\nWhen a bison herd feels threatened, they will surround the young and weak and face outwardly to create a living shield of body mass and horns. Even when not among the herd, this instinctual behavior takes over. A mother bison will stand between her calf and a pack of wolves.\n\nSome birds will \"dive-bomb\" passerby animals to repel them away from the nest, [as observed in this video](_URL_0_). In some cases, these attacks result in the death of the mother.\n\nWhen it comes to greed/murder in other species, this has been observed, most notably, in chimpanzees, orangutan, and other primates. For example, [chimps have fought turf wars](_URL_1_). In species of pack animals, the alpha member is usually the one who gets the largest portion of a kill. This can be viewed as greed. Similarly, jealousy and \"murders of passion\" have been observed throughout many species.",
"Love probably isn't the correct term, [altruism is.] (_URL_0_) Altruism is a concern for the welfare of others. Tons of species exhibit altruism."
]
}
|
[] |
[] |
[
[],
[
"http://www.youtube.com/watch?v=tsDLd9pkEG4",
"http://news.discovery.com/animals/chimp-war-behavior.html"
],
[
"http://en.wikipedia.org/wiki/Altruism"
]
] |
|
1k3sfn
|
Are electric solar cells on top of cars an effective method of transit?
|
I would assume that a standard car uses more power than a solar cells could provide, but the solar cells have the advantage of being able to charge the battery while the car isn't running. Is it effective?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1k3sfn/are_electric_solar_cells_on_top_of_cars_an/
|
{
"a_id": [
"cbom51g"
],
"score": [
2
],
"text": [
"Time for a \"back of the napkin\" thought experiment!\n\nSay that you have [a Chevy Volt](_URL_2_) with the following characteristics:\n\n* 110 kW engine\n* you drive your car for 3 hours per day\n* while you're driving your car's average power output is 50% of installed power\n* your car is outside 100% of daylight hours with a clear view of the sun\n* where you live a 1 kW solar panel generates 1,600 kWh of annual energy, or 4.384 kWh per day\n* the solar panels available have a power per area of [0.146 kW per square meter](_URL_0_)\n\nYour car uses **0.5 x 110 x 3 = 165 kWh** per day.\n\nThis would require your car to have **165 / 4.384 = 37.64 kW** of installed solar panels.\n\nThose solar panels would take up **37.64 / 0.146 = 257.8 square meters** of space. That is an area just larger than half of an NFL endzone.\n\nSo, as previously mentioned, the space needed to install the required number of solar panels is much too large. I think that some Smart Cars have solar panels on the roof ([source](_URL_1_)), however this is not used to actually drive the car but just to top up the battery and not use the alternator at some times, which decreases engine load and thus increases fuel economy."
]
}
|
[] |
[] |
[
[
"http://www.affordable-solar.com/store/solar-panels/CSI-CS6P-235PX-235W-Solar-Panel",
"http://www.topspeed.com/cars/smart/2011-smart-car2go-edition-with-solar-roof-ar97353.html",
"http://en.wikipedia.org/wiki/Chevrolet_Volt"
]
] |
|
3unth6
|
Does my phone use more battery if i use its in-built speaker or with headphones?
|
I doubt it's relevant but if it is, my phone is an LG G3, Android version 4.4.2
|
askscience
|
https://www.reddit.com/r/askscience/comments/3unth6/does_my_phone_use_more_battery_if_i_use_its/
|
{
"a_id": [
"cxgwc6z"
],
"score": [
9
],
"text": [
"Headphones and the integrated speaker are both powered by the phone's battery.\n\nA small experiment: \n\n-Place the headphones and the phone at equal distances, in turn, turn the volume to max then play a song.\n\n-You will barely hear the headphones while the speakers will be very loud.\n\nThe sound energy from the speakers is much greater than the headphones. The speakers will drain more of the battery while in use."
]
}
|
[] |
[] |
[
[]
] |
|
11cm7y
|
how come when were not thinking of something, we don't sense it?
|
Kind of badly worded, but I mean like, it you don't think about blinking or breathing, you'll still be doing it, you just wont sense it, but if you start thinking about it, then you'll sense it until you forget about it. (Again, sorry for it being poorly worded)
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/11cm7y/eli5_how_come_when_were_not_thinking_of_something/
|
{
"a_id": [
"c6l9vwv"
],
"score": [
4
],
"text": [
"And now you've made everybody self-conscious of their breathing! :-)\n\nI don't know the exact mechanisms for things like breathing and blinking, but I *imagine* it's a similar concept to (for example) when you place your hand on a table and you feel the surface, but after a while you forget about it.\n\nIn these cases, it's to do with 'brain boredom'. Your job - as an animal - is to remain hyper alert of *changing* conditions, so that you can respond quickly to them and ensure your survival. When your brain detects that something *isn't* changing, it automatically filters it out, so that you can focus on other things instead. So, the sensation *is* still there, in a way, but your brain is deliberately ignoring it."
]
}
|
[] |
[] |
[
[]
] |
|
1ujhtj
|
Books on Political economy for beginners?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1ujhtj/books_on_political_economy_for_beginners/
|
{
"a_id": [
"ceiqhap",
"ceiryjn",
"ceis71o",
"ceit85u",
"ceitlue"
],
"score": [
4,
3,
2,
2,
2
],
"text": [
"I'm currently reading Robert L. Heilbroner's \"The Worldly Philosophers\" which gives an outline of the basic ideas behind the thinking of Smith, Marx, Mill, Keynes etc… Though I have found it fascinating it is slightly muddied by Heilbroner's biases, as the works of Hayek, Friedman, Rothbard and others are entirely ignored or only given passing reference. Otherwise though, it gives a great beginners guide to the ideas of several pivotal figures.",
"I just took a class on International Political Economy and the textbook we used was Thomas Oatley's [International Political Economy](_URL_0_) which struck me as readable and pretty approachable for beginners. It is not, however, a theoretical or philosophical discussion of political economy. \n\nI'm also currently reading [A Political Economy of the Middle East](_URL_1_) but I am not sure I would recommend it unless you had had some intermediate econ courses at least. ",
"/r/asksocialscience might be a better place to ask. That being said, I can suggest a text: [\"Theories of Political Economy\" by Caporaso & Levine](_URL_0_). It seemed like a solid primer when I TA'd an intro course last year, and it's fairly concise. However, it is old and there may be better alternatives.\n\nAny background in political philosophy, political science, or basic micro- and macro- economics will help a lot. Depending on your focus, I'd add international relations to that list.\n\nHistorical literacy is also a must. As with any field, there's some intellectual history to consider, and this is *particularly* true of political economy.",
"My wife actually published a fairly accessible textbook on Political Economy which is pitched at the introductory college level. \n\n[There's plenty of used copies out there](_URL_0_) and there's been no need for a second edition so, if you're interested I'd pick it up used; I certainly can't see any reason you'd want to throw down $70+ for it.",
"Muller, [*Adam Smith in His Time and Ours*](_URL_1_)\n\nJohn, ed., [*Ruling Passions*](_URL_0_)"
]
}
|
[] |
[] |
[
[],
[
"http://www.amazon.com/International-Political-Economy-5th-Edition/dp/0205060633",
"http://www.amazon.com/Political-Economy-Middle-East-UPDATED/dp/0813349281/ref=sr_1_1?s=books&ie=UTF8&qid=1389028147&sr=1-1&keywords=political+economy+of+the+middle+east"
],
[
"http://www.cambridge.org/us/academic/subjects/politics-international-relations/comparative-politics/theories-political-economy"
],
[
"http://www.amazon.com/International-Political-Economy-Navigating-Introduction/dp/0757578330"
],
[
"http://www.amazon.com/Ruling-Passions-Political-Economy-Nineteenth-Century/dp/0271028971/ref=tmm_pap_title_0?ie=UTF8&qid=1389031778&sr=8-1",
"http://www.amazon.com/Adam-Smith-His-Time-Ours/dp/0691001618"
]
] |
||
4gpncc
|
how do animals survive being struck by lightning if the temperature of an average bolt is 5 times of that of the surface of the sun? (roughly 30,000 kelvin)
|
[Apparently this bison got struck by lightning. Seems alright to me. Sorta.](_URL_0_)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4gpncc/eli5_how_do_animals_survive_being_struck_by/
|
{
"a_id": [
"d2jlbqm",
"d2jtgf4"
],
"score": [
6,
56
],
"text": [
"Temperature is not the same as heat. Tiny samples of atoms in the LHC can reach trillions of degrees, but because there are so few, there isn't much heat and it dissipates quickly. Same thing with lightning. The temperature increase is relatively short-lived.",
"How much heat you absorb is a function of both temperature and time. A lightning strike is over in a millisecond, so only a small amount of energy is transferred. It is enough to burn the skin, but not enough to damage anything internal. It's sort of like how if you cook at too high of a temperature you can burn the outside of meat and still have the inside undercooked."
]
}
|
[] |
[
"https://www.doi.gov/sites/doi.gov/files/uploads/NealSmithNWRKarenVisteSparkmanFWS.jpg"
] |
[
[],
[]
] |
|
b3hppe
|
how do animals like geckos and other lizards climb on smooth walls like concrete?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/b3hppe/eli5_how_do_animals_like_geckos_and_other_lizards/
|
{
"a_id": [
"eizs89s"
],
"score": [
2
],
"text": [
"Their fingers are covered by very tiny textured bristles, called setae, which hook into and around the tiny irregularities on the surfaces they're climbing."
]
}
|
[] |
[] |
[
[]
] |
||
92agda
|
in footage of nuclear explosions, what are the white vertical stripes?
|
As seen for example [here](_URL_1_) and [here](_URL_0_)? Another question about nuclear explosions, I once read on Reddit about the experiences of someone who as a kid was watching some nuclear test in Mojave, I think, and he said that at the moment of detonation he saw these speckles of very weird colours. Does this really happen and if yes, why?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/92agda/eli5in_footage_of_nuclear_explosions_what_are_the/
|
{
"a_id": [
"e349fz1",
"e349ir7",
"e349j0j",
"e34n82d",
"e34o7zt",
"e34tpqw",
"e34v3hs",
"e352a38",
"e35czno",
"e35lmzv",
"e35temt"
],
"score": [
15,
283,
5057,
76,
40,
32,
13,
4,
2,
2,
2
],
"text": [
"The vertical stripes I think are for measurement of the shockwave / pressure wave. So they can calculate its velocity. ",
"Those are smoke trails from smoke rockets. Before nuclear tests, they would sometimes fire smoke rockets up into the air near the blast location, which would allow them to monitor the blast's shock wave by watching how the smoke trails moved in response.",
"Those are rocket trails. Just before launch small rockets are launched which leave those plumes of white smoke as they go up. Scientists can watch how the plumes behave in the vicinity of the blast and get a nice visualization of how the air around the fireball is behaving.\n\nIt is possible that the specks of white light at the time of the blast were from the interaction of high energy gamma radiation with the retina of the viewers. Radiation interacting with photoreceptors often appears as a small white speck or flash.",
"Pertaining to your second question, my grandfather was commissioned for some work on Enewetak atoll tests with the military. He recalled that the officers stood on a navy ship deck some signigicant distance away when it detonated. He held his hand up and could see through his hand like an xray. Maybe the speckles of light are a similar outcome of radiation exposure from the blast?\n\nEdit: He described it as holding his hand up and the light was so intense he could see his bones more or less",
"How can they sit \"so close\" completely exposed and not at least be sick from radiation?",
"They are used to calculate the yield if the bomb. Shoot a few small rockets in the air to make smoke trails in front of the camera, do a little trigonometry, and you can determine the size of the fireball/blast. This gives you yield.\n\n\nInteresting history, before the trinity test in July 1945, they carted out 200,000 lbs of TNT and filmed it explode so that they could use to baseline big explosions and later calculate the yeild of the actual nuke using visual techniques.\n\n\nI find it interesting that there was no crazy math or science used to calculate the size if the bomb, but rather just a test explosion with conventional explosives. That same method was used through the \"atmospheric\" testing days with the rocket smoke contrails.\n\n\nWhen they went to underground testing they had to develope another technique that I cant recall if its classified or not, so I will error on the side of not saying.\n\n\nSource: I am a nuke weapons engineer.\n\nEdit: just noticed your second question. atmospheric testing done on the mainland was done at the nevada test site (now called NNSS) that is about 1.5 hr drive North of vegas.\n\n\nSpeckles...hmmm, there are some materials (I wont name) that do make some really cool effects when you blow them up (think sparklers), however they only last a moment (high speed camera catches it) and only in conventional explosions. When it goes nuclear, everything is pretty much vaporized in less that 100 micro seconds and vapor doesn't really sparkle. Plus, he would have been mikes and mikes away and nonway would he been able to see that even if it wasn't vaporized. I call BS on his story. \n\n\nPlus they quit atmospheric testing decades ago, is this your grandpa or something?",
"Also, when nuclear detonations happen and you see what appears to be very thin spears of fire coming from the fireball, that's the support wires from the scaffolding that holds the bomb in the air, instantly vaporising because the heat is travelling faster through the metal than the air.\nExample [_URL_0_](_URL_0_)\n\n~~Edit:apparently I am wrong, thanks to u/smmstv for correcting! [_URL_1_](_URL_1_)~~\n\nEdit 2: nvm",
"They would launch rockets that would leave a smoke trail, so you could see how the air moves around the blast. You'll notice they get pushed outwards as the shock front passes, showing how the air moves. Sometimes they'll get sucked back in as the air behind the shock front gets more rarefied. ",
"Can atomic blasts have any affect on the angular momentum of our planet? or, do we know if any of the detonations caused a wobbling affect upon the Earth? Maybe bombs we've built now could have this magnitude of affect?",
"Question: does a nuclear bomb \"stuck in\" at first then expand? ",
"Another question here... In 100 years will these explosions look the same? It sounds a little crazy asking but the mushroom cloud and all that, is it set it stone or can they look different? Sometimes the cloud is not symmetrical or maybe \"ugly\" in a way that makes me think newer models would look more like cgi or closer to what might be drawn in a comic book."
]
}
|
[] |
[
"https://coubsecure-s.akamaihd.net/get/b54/p/coub/simple/cw_timeline_pic/8c3cc9f9c8b/3868c993c825949a485c1/med_1432310455_image.jpg",
"https://3.bp.blogspot.com/-4wiZIOGi3Nw/V9ctkBJi_qI/AAAAAAAALCc/Yty6idIbgwAHFWveeBS_Zn-JkonoJYbJACLcB/s1600/atomic_annie.jpg8"
] |
[
[],
[],
[],
[],
[],
[],
[
"http://www.waynesthisandthat.com/images/abomb8.jpg",
"http://www.reddit.com/r/explainlikeimfive/comments/92agda/-/e3533r2"
],
[],
[],
[],
[]
] |
|
4unw00
|
Do any encryption algorithms exist that are safe from attack by quantum computer?
|
If tomorrow someone announced (or any government intelligence agencies have) a feasible quantum computer capable of breaking encryption, would any algorithm be safe?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4unw00/do_any_encryption_algorithms_exist_that_are_safe/
|
{
"a_id": [
"d5s017y",
"d5s182y",
"d5sw76w"
],
"score": [
2,
3,
3
],
"text": [
"Yes, it is referred to as quantum cryptography, and may also require a quantum computer. We just hypothetically assumed they existed, right? The basic idea is that data is encoded in a quantum state such that reading that state alters it, and thus the data. That means that the participants of the communications can detect eavesdroppers. There is no passive way to intercept the data.\n\nThere are also algorithms based on lattice problems for which there are no known \"good\" quantum solutions (like Shor's Algorithm for the more traditional problems based on factoring the product of primes).",
"Yes. There is research into [post-quantum cryptography](_URL_0_). Also, that's just for public-key encryption. Anything where you use the same key to encrypt and decrypt, which is useful for encrypting password-protected stuff or if you're willing to send keys by courier, still works. Quantum computers can cut down the time significantly, but it just means you need a key that's twice as long.\n\nAlso, there's [quantum key distribution](_URL_1_), which does not require a quantum computer, but does require specialized hardware along the network so it's expensive and rarely used.",
" - Symmetric cryptography (AES, various SHA algorithms) is not affected *that much*: it is well-known that the quantum computer allows searching in O(√n) instead of O(n), so simply doubling the size of the keys is mostly enough.\n\n - Note that I wrote *mostly*, because [symmetric *modes* are affected much more](_URL_0_).\n\n - Almost all currently known asymmetric cryptography (RSA, elliptic curves, DSA) is basically killed by quantum computing. More precisely, Shor's algorithm reduces factorization and discrete logarithm to period-finding, which is polynomial on a (large enough) quantum computer.\n\n - But there is still hope for asymmetric crypto, in the person of *post-quantum cryptography*: basically any asymmetric algorithms not using discrete logarithm or factorizations. Despite being labelled as “exotic” until last year, some of these (such as McEliece) have been known for almost as long as RSA.\n\n - There is also that thing known as “quantum cryptography”, which is a confusing name given that it is something completely unrelated. A more proper name might be “physical key exchange protocol based on the quantum properties of light”, but that's far less catchy (as in: $-generating)."
]
}
|
[] |
[] |
[
[],
[
"https://en.wikipedia.org/wiki/Post-quantum_cryptography",
"https://en.wikipedia.org/wiki/Quantum_key_distribution"
],
[
"https://arxiv.org/abs/1602.05973"
]
] |
|
22g4cb
|
Has string theory been conclusively disproven?
|
I remember "superstring theory" being quite a hot topic during my last spurt of obsessive interest in theoretical science, around 2010 or 2011. I haven't heard anything about it, apart from references in those "gee-whiz" pop sci magazines, in quite a while. I asked Google whether it had been disproven, but sources on Google seem to differ quite a bit. Has string theory been conclusively disproven?
|
askscience
|
http://www.reddit.com/r/askscience/comments/22g4cb/has_string_theory_been_conclusively_disproven/
|
{
"a_id": [
"cgmiuxm",
"cgmkswp"
],
"score": [
6,
5
],
"text": [
"No, it hasn't been proven or disproven because A. it's not developed to the point where this is possible and B. we don't have the technology to experiment with quantum gravity. Certain choices of parameters that can be used to make predictions at the energy scale of the Large Hadron Collider can be ruled out by experiment, but there's nothing particularly telling about that.",
"It hasn't been disproven. Interestingly, you've stumbled on one of the greatest criticisms of string theory: that it is (with modern technology) \"un-disprovable\". The energies that would be required to conclusively prove or disprove string theory would be *astronomically* large! Literally! To definitively test string theory we would need enough energy to probe space on the order of the \"Planck length\", which would require a particle accelerator many millions of times more powerful than the LHC at CERN (which recently made the news for finding strong evidence of the Higgs boson). This is (with current technology) completely unfeasible! Yet, one of the defining features of a scientific theory is that it is *disprovable*, if it is not it is generally considered philosophy.\n\nAll that being said, physicists are not ready to disregard string theory as philosophy because:\n1. It just seems to describe the mathematics of the universe so neatly (relative to most other theories) and even wraps it up in a pretty little bow! And:\n2. It is *theoretically* disprovable (with enough technological know-how)\n\nSo, as said above the short answer is: No. It hasn't been disproven. But asking that question does probe at an interesting sore-spot of modern physical theory. :)"
]
}
|
[] |
[] |
[
[],
[]
] |
|
3rr2p7
|
why are GPS satellites put in LEO and not geostationary?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3rr2p7/why_are_gps_satellites_put_in_leo_and_not/
|
{
"a_id": [
"cwqm9rs",
"cwqu95m",
"cwr2j70",
"cwr3dci",
"cwradkv"
],
"score": [
14,
6,
4,
2,
2
],
"text": [
"Geostationary orbits are all over the equator. This would lead to sight line issues if you want to use GPS away from the equator. I live on a north facing hill in Canada so I can't get satellite TV signals. The only potential advantage to geostationary GPS satellites would be a few fewer lines of code in the receiver as the relative positions of the satellites don't change over time. The signals would be harder to receive and the costs to get the satellites into orbit would be much higher. Cost/benefit doesn't work out.",
"Geostationary wouldn't work that well for positioning. For accurate positioning, a receiver needs to see four or more satellites at very different angles. If you could only see four satellites all along one line, your positional accuracy would suck.",
"Are there any GPS satellites in LEO? I thought they were all in MEO, specifically at about 12 hour orbits. LEO needs to be reboosted periodically because of atmospheric drag, so MEO keeps you clear of that. It also lets one station on earth talk to every satellite in one day, keeping tract of where they are and what time their clocks have. \n\nSee [this interview with Brad Parkinson](_URL_0_), the Air Force colonel who managed the project in the 70's:\n\n\"Another issue we wrestled with is which satellite orbits to use. We did not want to be in geostationary or geosynchronous orbits. The reason was these alternatives would force us to deploy ground stations on the other side of the globe, whereas, by putting them in some orbit that periodically passed across the United States, you could update the knowledge of where they were and what time it was on the satellite, then store that information in the satellite and continue to broadcast as it went around the Earth. That is the fundamental way we ended up with twelve-hour orbits. We also wanted to be reasonably high because we didn’t want the orbits significantly disturbed by the atmospheric drag. At the same time, by going high you had more visibility, more coverage on the Earth. So with an Earth coverage antenna and suitable power densities on the Earth, you ended up with the ability of twenty-four satellites to provide very solid, total Earth coverage. Basically our original Labor Day proposal is still the current system. We had three rings of eight satellites, and they now have six rings of four nominally, but I’ve also seen studies that they may go back to three rings of eight. The reason we advocated three rings of eight is to allow replenishment so much easier. You can store one extra satellite in each ring and then just let it drift around to a spot where you need a replacement. With the six rings, they obviously would need twice as many spares on orbit.\"",
"They are actually put in MEO. It's lower than geosynchronous but still much higher than LEO.\n\n_URL_0_\n\nGeostationary satellites, trivially, would only be able to provide service to a small range of longitudes.\n\nThe first version of the Chinese BeiDou navigation system initially had 4 satellites in the geosynchronous orbit and it worked reasonably well... for China and surrounding areas. In the new system satellites are being launched into MEO to be able to provide worldwide service.\n\n_URL_1_\n\n_URL_2_",
"additional piece not mentioned by others, the satellites cannot all be in the same orbital path or you have multiple solutions to the position equation. for example you could be 20 degrees latitude north or south of the equator and get the exact same times from the satellites. for this reason the gps satellites are in three, 120 degree offset, orbits."
]
}
|
[] |
[] |
[
[],
[],
[
"http://ethw.org/Oral-History:Brad_Parkinson#Parkinson.27s_educational_background_and_the_origins_of_GPS.5D"
],
[
"https://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Comparison_satellite_navigation_orbits.svg/2000px-Comparison_satellite_navigation_orbits.svg.png",
"https://en.wikipedia.org/wiki/BeiDou_Navigation_Satellite_System#Experimental_system_.28BeiDou-1.29",
"https://en.wikipedia.org/wiki/BeiDou_Navigation_Satellite_System#Global_system_.28BeiDou_Navigation_Satellite_System_or_BeiDou-2.29"
],
[]
] |
||
eyvcrw
|
How effective are surgical masks at reducing the chance of infection for the user? How effective are they against spreading germs that can cause infections if the user is infected?
|
askscience
|
https://www.reddit.com/r/askscience/comments/eyvcrw/how_effective_are_surgical_masks_at_reducing_the/
|
{
"a_id": [
"fgo0are",
"fgjrmjd",
"fgk15ka",
"fgk8m8w",
"fgmuc23"
],
"score": [
2,
4,
9,
8,
2
],
"text": [
"To add on to what other folks said, not very.\n\nWhat they ARE somewhat effective at doing is actually preventing you from infecting other people if you're sick--it keeps the droplets from your mouth/nose from spreading very far, and also keeps you from touching your face as much.",
"Kind of depends on the mask, the virus/bacterium/whatever, and how the mask is being used. \n\nFor example an n95 mask is generally really effective at keeping the flu and other droplet type illnesses (common cold, etc) from crossing said barrier. But when wearing masks long term, once the mask starts to become slightly damp from exhaling, if you don't change it promptly it becomes contaminated/useless.",
"If they're not rated N95 and sealed properly, not much use. Those fabric masks with tiny \"filters\" sold for pollution, cycling, etc. are useless.\n\n[“Right now, there’s no evidence that (wearing face masks) is going to help prevent that infection,” Dr. Charles Chiu, a professor of medicine at University of California San Fransisco and an infectious disease expert, told CNN. “I would not recommend that someone in the U.S. who does not have direct exposure, did not recently travel to China ... go buy a face mask.”](_URL_3_)\n\nAnd\n\n[“The virus is not spreading in the general community,” Nancy Messonnier, director of the Center for the National Center for Immunization and Respiratory Diseases, said in a briefing Thursday. “We don’t routinely recommend the use of face masks by the public to prevent respiratory illness. And we certainly are not recommending that at this time for this new virus.”](_URL_1_)\n\nAnd\n\n[Large scale panic buying of face masks could actually be counterproductive.](_URL_2_)\n\nAnd\n\n[But there's little evidence to suggest that the face masks worn by members of the public prevent people from being infected by breathing in the virus, says William Schaffner, a professor in the division of infectious diseases at Vanderbilt University Medical Center. \"There really are no good, solid, reliable data.\" According to the CDC, the kind of flimsy masks that people often buy in pharmacies may not tightly fit the face, so the wearer can still breathe in air — and infected droplets. Stanley Perlman, a professor at the University of Iowa who studies coronaviruses, agrees that the mask won't necessarily prevent infection. But they do have some value, he says: Wearing a mask may stop an individual from directly touching their mouth and nose, which is a common way that viruses and germs enter the body. Masks provide some protection this way, he adds. \"But what we teach is that they're not very good.\"](_URL_4_)\n\nAnd\n\n[The CDC does recommend masks for \"People Confirmed to Have, or Being Evaluated for 2019-nCoV Infection Who Receive Care at Home.\"](_URL_0_)",
"It depends on how the infectious organism is spread. Surgical masks are effective against those infectious organisms spread through respiratory droplets, an example of this is the influenza virus. N95 masks protect against airborne transmissible infectious organisms, an example of this is the tuberculosis bacterium. The problem with surgical masks is that people don't understand how to use them. They're good for wearing for only 4 hours so they need to be changed after that and they also need to be changed if they get wet.",
"They don't do much to help with bacteria and certainly not viruses, it's common sense really. They aren't air tight anyway, it's like someone saying there is gas in the air so you pull your t-shirt up over your nose It's not going to help you.."
]
}
|
[] |
[] |
[
[],
[],
[
"https://www.cdc.gov/coronavirus/2019-ncov/hcp/guidance-prevent-spread.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fcoronavirus%2F2019-ncov%2Fguidance-prevent-spread.html",
"https://www.marketwatch.com/story/the-cdc-says-americans-dont-have-to-wear-facemasks-because-of-coronavirus-2020-01-30",
"https://www.nytimes.com/2020/01/29/health/coronavirus-masks-hoarding.html",
"https://www.deseret.com/u-s-world/2020/1/28/21112223/surgical-mask-coronavirus-wuhan-china-n95-respirator-utah-cdc",
"https://www.npr.org/sections/goatsandsoda/2020/01/25/799007842/coronavirus-faqs-do-masks-help-is-the-disease-really-so-mysterious"
],
[],
[]
] |
||
3pcfaz
|
AMA: The Atlantic Slave Trade, especially human trafficking between the colonies throughout the Americas.
|
I'm Greg O'Malley, author of [Final Passages: The Intercolonial Slave Trade of British America](_URL_2_) and a history professor at [University of California, Santa Cruz](_URL_1_). I'm currently a fellow at the [Virginia Foundation for the Humanities](_URL_0_). I'm here today to answer questions about the slave trade...or related topics of slavery, colonial America, and the Atlantic World. (You can also follow me on Twitter: @gogogomalley.)
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3pcfaz/ama_the_atlantic_slave_trade_especially_human/
|
{
"a_id": [
"cw535hq",
"cw535js",
"cw53isf",
"cw53li4",
"cw53uht",
"cw540yv",
"cw54gyq",
"cw54juk",
"cw54n9z",
"cw54s30",
"cw54tpx",
"cw54xzl",
"cw55me9",
"cw56dgi",
"cw56vbf",
"cw572u4",
"cw57wmg",
"cw57yjm",
"cw5877y",
"cw588by",
"cw58yls",
"cw59fiu",
"cw5a8vs",
"cw5a9ge",
"cw5ayt1",
"cw5b20k",
"cw5bl3q",
"cw5byfo",
"cw5c0pr",
"cw5foix",
"cw5idbs",
"cw5izrn",
"cw5j305",
"cw5jcl7",
"cw5jrc1",
"cw5jwvr",
"cw5k2on",
"cw5kvzh",
"cw5lh7j",
"cw5n22n",
"cw67i8t"
],
"score": [
15,
16,
15,
10,
7,
9,
4,
3,
4,
3,
2,
3,
42,
8,
2,
6,
2,
4,
2,
2,
2,
2,
2,
4,
2,
5,
4,
2,
3,
2,
7,
4,
2,
2,
2,
2,
5,
4,
2,
5,
5
],
"text": [
"Hi, Professor O'Malley, thank you for presenting this AMA! \n\nI've heard various arguments as to the motives behind the British move to disrupt the Atlantic slave trade through the Royal Navy - chief of which was that the slave trade was highly profitable for the French, with whom the British were at war. That being said, I'm not at all familiar with the topic, and have little idea of why the British became involved in actively interrupting the slave trade and the means by which they did so. Is there any chance you'd be able to clarify the British motives for ending the Atlantic slave trade and the means by which they did so?\n\nMany thanks!",
"Was there human trafficking between the colonies of different European nations in the Americas (English, French, Spanish, maybe even Dutch and Portuguese)? As these nations made war and peace with each other over time, did this change the nature of human trafficking between their colonies? \n\nThanks in advance for your answer! ",
"Thanks for doing this AMA!\n\nAre there reliable estimates on the number of slaves both taken from Africa against how many were born in America? How much do such estimates vary, and why? I've heard it also said that the number of slaves that reached North America could be a bad estimate, as many slaves who arrived in the Caribbean were subsequently shipped to South America, whilst being reported as going to N.A. As a continuation of this, could the Atlantic Slave Trade be classified as an event similar to the Holocaust? ",
"Thank you for doing this AMA, Professor! Unfortunately my knowledge of American history could fit in a thimble, so I have...a lot of questions.\n\n1. According to [this Amazon reviewer](_URL_0_), most of the trade activity you studied was: transatlantic ships arrived in the Caribbean, sold off mainly the healthy men to plantation owners there--and then intercolonial traders purchased the remainder, to sell down to French and Spanish America (along with commodities). Did this gender/health/age imbalance affect plantation development in the different areas at all? (I'd love to know how it affected slaves' experience, but it sounds like that's outside the scope of your study.)\n\n2. Again according to that review, you argue that the interim traders used slaves basically as an excuse to trade raw goods like sugar and rum, and this helped promote the rise of Britain in world trade. Did you see any kinds of coordinated 'national' effort, like laws in the Caribbean restricting interim trafficking to ships of British origin? Or was this just individual profit-seekers who happened to be British? Was this trade taxed at all, and by whom?\n\n3. Were conditions on the intercolonial ships as bad as the Middle Passage?",
"Was there a 'direction of the flow' of the intercolonial slave trade - were slaves sold from one region and bought by another? If so, what was it? Did this change over time?",
"Thank you sir for this!\n\nHow large an effect did Caribbean piracy have on the slave trade? Were there any pirates who targeted slavers in particular?",
"Were there particular sets of skilled laborers from Africa who were prized and sought out by slavers for transport to the Americas for their particular craft?",
"Were escaped slave communities in Spanish America ever well enough organized to pose a fundamental threat the very survival of large Spanish towns/cities? What did the Spaniards do about the large escaped/free black populations?",
"What were the profit margins of a single voyage? Or of a transatlantic slave businessman over time?",
"Were there ever large communities of escaped slaves in the hinterlands of the British Empire? Why or why not? And if there were, what happened to them?",
"Was the city of Bordeaux, France a part of the slave trade? If so, are there records of the captains of ships that sailed from those ports? I'm looking for info on a Captain Jarreau. ",
"Do you know about any differences in the slave trade in Northern colonies versus the southern ones?",
"Apparently of all the millions of slaves, only a smaller number (400k out of 12m or thereabouts?) went to North America. I don't mean to relativize suffering or anything, but how come the NA slave narratives and history seem so much more known, prevalent and common?\n\nIs it 'just' because of US influence in general - much like, say, the portrayal of US and WW2 in popular culture and history?\n\nOr was NA slavery somehow worse than further down in Central/South America?\n\nOr perhaps better yet, what are the distinctive, major differences\nor traits - if any - of slavery in NA in comparison to SA?",
"How much of a role did Bacon's Rebellion play in creating racism? I've heard that since black slaves and white indentured servants made common cause in the rebellion, afterwards the powers-that-be in Virginia put a divide between the two groups by, for example, passing laws that discriminated by race. The intent, or at least the result, was that white indentured servants started to see themselves as superior to the African slaves. How important of a factor was this in creating racism?\n",
"Thanks for the AMA!\n\nOne thing I've been wondering is how Dutch plantations (which relied on enslaved labor) in Suriname and the Antilles continued to be supplied with enslaved people after the (legal) abolition of the slave trade in 1814. Is there any evidence of heavy dependence on an intercolonial slave trade? ",
"Thanks for doing the AMA \nIm European and so the slave trade is probably not as strongly discussed in our society as it is in the USA (even though its teached in school) \n\nHow is it to do research about a subject that people have very emotional feelings and opinions about? Do you sometime have to change certain sentences or words to not offend anyone?",
"I have heard it said that the majority of slave traders were Jewish and that the majority of slaves ended up in south America. Is there any truth to either of those claims? \n\nIf it's true that most were Jewish why would that have been? ",
"The general impression is that colonial era slaves are black, indentured servants were white, but there is little mention and small evidence that indigenous people from the Caribbean or South America were enslaved and brought to the North American Colonies. \n\nIs that an accurate overview? \n\nWhat accounts for the lack of SA Indigenous people with a slave history in the US?\n\nThanks",
"Hello Professor,\n\nI've read that, when Spain took over control of Louisiana in the 1760s, the laws governing slaves changed. In particular, the government enforced laws already in use in colonies like Cuba, including the concept of *coartación*, where slaves were given the right to buy their own freedom. \n\nWhat accounts for the difference in philosophies towards slavery between the Spanish and the British or French, whose colonies apparently did not afford slaves similar rights?\n\nThanks very much for this AMA.",
"So how widely reviled was salary by the end of Napoleonic War? How did various navies dealt with the salve trade once the slavery and slave trade was declared as illegal by their countries?",
"Professor, you often hear about how the treatment of slaves in Africa differed from the treatment of slaves in the colonies. My question is what were those differences? Did the colonies always practice chattel slavery? And was slavery in sub-Saharan Africa really more like serfdom than chattel slavery?",
"Hello, professor, and thank you for conducting this AMA! To what extent does the anti-Semitic belief that Jews were disproportionately represented among trans-Atlantic slave traders or American colonial slave auctioneers hold any weight?",
"I've heard that real escape from slavery in the Caribbean, since they were islands, was impossible, whereas American slaves could walk over the border. Was there considerably lower incidence of runaways from the Caribbean?",
"Hi, I'm not sure if I'm too late but it's great to see examination into this subject matter when some school boards are trying to minimize it in textbooks.\n\nWas there a typical origin by tribe or present-day African nation for slaves which were sold for the Atlantic passage? Did it change over time due to regional or tribal wars at all?",
"Have you considered exploring European slave trading in the Indian Ocean during the early modern period? Historians like Phil Stern argue that patterns of Atlantic slaveholding were important in the development of forms of forced labour at East India Company settlements such as St Helena and Bombay.",
"It's slightly off subject, but I'm interested in the effect of the slave trade on Africa. \n\nWhat was the effect of so much manpower being drained away?\n\nWere there economic shocks when slavery was outlawed?",
"I'm really curious about Islam in the New World. Obviously some of the slaves that were brought to the New World were Muslim, and I know they were treated in different ways (particularly with the Spanish trying to ensure their conversion). How did slave owners in different areas view Muslim slaves as opposed to those that practiced traditional African faiths? Did the Dutch, for instance, treat these slaves differently from the Americans, British, or Portuguese?",
"Was there a notable difference in the way different countries/companies conducted slave trade in respect to how they treated the enslaved between capture and sale?\n\nWere there for example different ideas about how to treat them either because of pure moral reasons, or because of business reasons ('keeping slaves healthier and safer will be good for business'). And if so, how did these countries/companies try to differentiate themselves?\n\nOr was treatment of Africans mostly the same across the board?",
"This is a bit after your time period and area focus, maybe, but you probably know enough about the state of the field. My question is whether the War of 1812 and the Indian wars of the early 19th century opened up the Southwest frontier to intensive settlement and cotton cultivation, giving slavery a shot in the arm in the American deep south. Do you know of any current scholarship that backs this up? On a related note, is it true that the large sugar and cotton plantations of the lower Mississippi were net \"consumers\" of slave labor, because of the harsh conditions and prevalence of disease? I've always thought the term \"sold down the river\" came from the domestic American slave trade, where slaves from states like Kentucky or Tennessee were always under the threat of being sold down the Mississippi to much worse situations.",
"One reason I've heard about why recently enslaved Africans didn't try to escape once they reached America was because the Middle Passage was so horrible that it psychologically broke their will. Is there any validity to this theory? If so, was it intentional on the part of the slave traders?",
"Holy cow. This is a lot of questions. I'm getting tired, but I'm trying to get to all of them!!!",
"How accurate is Thomas Sowell's \"Black Rednecks and White Liberals\"?\n\nSpecifically interested in the Scottish immigrant culture and how it had passed through to what we now know as modern 'Black culture' before, during, and after slaves arrived in the American South. \n\nAlso very interested in your thoughts on Sowell's downplaying the American decision to emancipate-- that it was probably the 'right' decision at the time.\n\nThanks!",
"Are there current estimates of percentages of slaves who had white (male of course) parentage up until the end of the civil war?",
"Is it possible to roughly determine how many total \"slave-years\" there were? For instance, a man dying at 50 who was born into slavery contributes 50 slave-years to the total. I'm trying to get that figure to compare it to the number of prison-years since, seeing as how we have about 2 million in jail at a time every year. Is it calculable? \n ",
"What is the best method for an African-American to pinpoint their ancestry within Africa geographically?",
"Hopefully I'm not too late, but - immediately after emancipation, what happened to slaves that had been owned by very wealthy / upper class families and had a better quality of life than most slaves, having learned to read and write etc? \n\nwas it easy for them to find employment as clerks etc? where there any professions they particularly gravitated towards because it was easier for them to get them or where they forced to take jobs that didn't allow them to use their skills because that's what they could get?\n\nI'm wondering because you see portraits, in the national gallery (UK), of well-dressed child clerks or something similar, and I know from reading that they were almost ornamental and it was very trendy to have a african child slave at the time. So what would have happened to these educated 'house slaves' once they were freed?",
"Hello! Thank you for doing this AMA about a troubling subject most of us know too little about! I have added your book to my reading list!\n\nMost textbooks on U.S. history focus on slavery just before the Civil War but I have a few questions about slavery and attitudes toward people of African descent in the 18th century.\n\n1. One thing I often read in more casual writings on history, is that Europe was far \"less racist\" because slavery was extremely rare, and thus black people never really came to be viewed as underclass. But paintings from this era in England, France, Spain, and Italy, often portray page boys or servant women of African descent in what definitely seems to be a servile, inferior position. Could you tell us a bit more about this, were such people indeed slaves or more often servants?\n\n2. For certain individuals, who might be descended from slaves, but born free and/or benefited from some exceptional social advantages, what was life like? Famous examples that come to mind include the Chevalier de Saint-Georges or Dido Elizabeth Belle, subject of a recent (slightly romanticized) film. What degree of success might they hope to attain, and how respected would they be by their white contemporaries?\n\n3. Just how active were former slaves in early abolitionist movements? I understand some would testify before abolitionist societies concerning their inhumane treatment, and that some wrote \"slave narratives\" that were published with the help of abolitionists. But it seems like members were still usually wealthy and white. What about freedmen and women who might not have a such harrowing tales to tell, but still wanted to contribute to the anti-slavery movement?\n\n4. What were the attitudes of the \"typical\" white person in American society shortly before and after the revolution? Those who might not own slaves (or deal in business dependent on slavery), but were not members of abolitionist societies. ",
"It's a bit outside the scope of your work mentioned here, but how unequal was the trade between Europeans and local Africans? Were Europeans coercing Africans into giving up slaves, or was the trade relatively bilateral?",
"Do you know what percentage of white inhabitants here in Barbados would have been slaveowners throughout the history of the colony until 1834? I'm under the impression that it would be the majority. \n \nAlso, did the Barbados Slave Code of 1661 make things better, or worse, for the enslaved, and how much did it influence the practice in the rest of the Americas?",
"Why Brasil was the place where most of the slaves were sent?And after the prohibition of the slave trade in Brazil, how impactful was for the market?",
"Is your book a good introductory work for someone that knows only the basics of the Transatlantic Slave Trade, or do I require some deeper knowledge before going for the book?"
]
}
|
[] |
[
"http://virginiahumanities.org/",
"http://history.ucsc.edu/faculty/profiles/singleton.php?&singleton=true&cruz_id=gomalley",
"http://www.amazon.com/Final-Passages-Intercolonial-1619-1807-Williamsburg/dp/1469615347/"
] |
[
[],
[],
[],
[
"http://www.amazon.com/review/R36FJZTS8EHDNW/ref=cm_cr_dp_title?ie=UTF8&ASIN=1469615347&channel=detail-glance&nodeID=283155&store=books"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
|
g19m8p
|
why isn't gravity scaled to smaller things?
|
Like if I took a 100ft wide ball and a .5cm wide marble why wouldn't the marble be attracted to the ball? Or would it be attracted and I've lived my entire life without this info
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/g19m8p/eli5_why_isnt_gravity_scaled_to_smaller_things/
|
{
"a_id": [
"fne80ha",
"fne82p8",
"fne83i8",
"fne87yd",
"fne8eo4",
"fne8tqs",
"fne9bk0",
"fnea1nx",
"fnedlvj"
],
"score": [
7,
48,
2,
5,
3,
26,
3,
3,
2
],
"text": [
"I read somewhere once that if you put 2 pens floating in space near each other, after a very long time they would eventually gravitate towards each other. It does happen, it would just take a very very very long time",
"They are attracted. All things with mass are always pulling on all other things with mass. But it takes A LOT if mass to make a difference. So if you have a large and small ball, both are still pulled to the earth. Earth is a bigger ball.",
"It is. All objects/particles with mass (or energy) exert a gravitational pull on the objects/particles around them.",
"They are attracted to each other through gravity, it's just such a small effect that there's practically no way to measure it and they'll have practically no effect on each other. Every object in the universe has gravity pulling everything else towards it - a marble, a planet, you and me. But gravity's effects are so weak at small scales that they're almost unnoticeable - it scales up really well though so that when you get to the size of a planet or a moon, it becomes really significant.",
"They are attracted to each other, it's just a basically non-existent force compared to the gravity of Earth, friction, inertia, ect. that keep the marble and the ball stationary.\n\nIn the vacuum of space without any other forces, they would (very slowly) come together.",
"Scientist Henry Cavendish [did exactly that](_URL_0_) with two different-sized balls in 1797 and successfully measured how strong gravity is, to within 1%.",
"This is how the gravitational constant is measured. Henry Cavendish did [an experiment](_URL_0_ ) in the 1790s to measure the strength of gravity without using the Earth as a mass. This was important, as the mass of the Earth was not known accurately. The experiment used 2-inch (51 mm) diameter 1.61-pound (0.73 kg) lead balls, and 12-inch (300 mm) 348-pound (158 kg) lead balls to measure how the large balls attracted the small balls.",
"They are attracted. The problem is that at that small scale, the attraction is so small that it is easily negated. \n\nIn fact, one of the first ways we measured the gravitational constant was the [Cavendish Experiment](_URL_0_), which involved the gravitational attraction of two balls. You can check out a video with a demonstration of the experiment [here](_URL_1_). The experiment needs to take advantage of some stuff to scale up the value to something that actually has a measurable effect at the scale.",
"Aside from other answers, people don't realise Gravity is VERY VERY weak. People see it as strong , but that's only because it's one of the easiest forces to observe.\n\nThey do attract, but the force between the two is a joke compated to the earth."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Cavendish_experiment"
],
[
"https://en.wikipedia.org/wiki/Cavendish_experiment"
],
[
"https://en.wikipedia.org/wiki/Cavendish_experiment",
"https://www.youtube.com/watch?v=2PdiUoKa9Nw"
],
[]
] |
|
6sx545
|
Where is all the nuclear contamination from the atmospheric nuclear tests decades ago?
|
According to the CTBT, the United States has conducted 219 atmospheric nuclear tests. Did this not cause worry once we knew radiation travels? Are these regions still contaminated? Do we avoid them altogether in flight/sea travel?
|
askscience
|
https://www.reddit.com/r/askscience/comments/6sx545/where_is_all_the_nuclear_contamination_from_the/
|
{
"a_id": [
"dlgf2rg",
"dlghkl2",
"dlghwy3"
],
"score": [
5,
9,
16
],
"text": [
"It's still there. The atmosphere is just so big that it's not a major health concern. Natural sources of radiation lead to a dose of about 2.4 milisieverts but can range from about 1 to over 10 milisieverts. Radiation from atmospheric nuclear testing peaked in the 90s at about 0.1 milisieverts and now the dose is only about 0.005 milisieverts [[source](_URL_0_)].",
"Bikini Atoll today looks pretty much like a normal tropical island with fish and palm trees, except the coconuts concentrate heavy metals from the soil and are [slightly too radioactive to eat.](_URL_1_)\n\nThe main enduring contaminant is cesium-137, courtesy of a whopping 23 nuclear tests on the same cluster of islands. This is one of the most nuked places on Earth and it's down to a level where you could live there if you really wanted to. Just, don't farm there.\n\nAs for avoiding it, today we don't have to but at the time this was kind of a big deal. While the U.S. was doing Castle Bravo on this island we kind of forgot to tell the Japanese that they should move their fishing fleets out of the way of the fallout plume and irradiated fishermen and their catches hundreds of miles away. [Whoopsies.](_URL_0_)",
"The nature of nuclear radiation is such that it decays over time. As u/frogjg2003 pointed out, the nuclear fallout from all of the testing is still present in the environment--but it's radioactivity has decreased, or *decayed,* over time.\n\nTo put it another way, it is not as radioactive as it used to be.\n\nThe second thing to keep in mind is that the nature of nuclear fallout is that it disperses over time and distance from the explosion. Think of it like smoke: right up next to a large fire, the smoke is dense and choking--but a couple of hundred meters away, it's a lot thinner, more dispersed, and not so dangerous.\n\nFallout is sort of like radioactive smoke: it spreads out and gets diluted in the atmosphere as it moves away from ground zero. It eventually settles to the ground (falls out of the atmosphere), but by that point it is spread over a much, much larger area, so the radiation dosage you would get standing in RE fallout area say, 20 km from ground zero, is a lot less intense than it would be at 500 meters.\n\nWhen atmospheric testing ended, we stopped making more fallout, so the contamination that existed at that time is all there is. Over the years since, it has become less radioactive to to decay.\n\nThat said, it is still not a good idea to hang around nuclear test sites; the Trinity site, the original, is still radioactive enough that it's not safe to spend a long time on-site. You might not develop acute radiation sickness, but it will *definitely* increase your chances of developing cancer later in life."
]
}
|
[] |
[] |
[
[
"http://www.unscear.org/docs/publications/2008/UNSCEAR_2008_Report_Vol.I.pdf"
],
[
"http://www.telegraph.co.uk/news/2016/04/08/japanese-fishermen-to-sue-over-fallout-from-bikini-atoll-nuclear/",
"http://www.pnas.org/content/113/25/6833.full"
],
[]
] |
|
6aytt5
|
why does black absorb sun rays so much?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6aytt5/eli5_why_does_black_absorb_sun_rays_so_much/
|
{
"a_id": [
"dhig2pz",
"dhig41j",
"dhiggch"
],
"score": [
5,
2,
2
],
"text": [
"Colors we see are perceived by light rays (certain wavelengths) that are reflected. Meaning the object doesnt absorb that color. For example, apples reflect the color red. White reflecting all colors essentially and black reflecting no colors. Since black is absorbing these colors and light rays contain energy it heats up faster.\n\nHope that helps. I may be a bit off on the details but the gist is correct.",
"Dark colors are a result of a particular pigment or material that absorbs pretty much all the light that comes into contact with it. Wearing black means your absorbing all the light, along with its energy, when it hits you.",
"Since it doesn't appear on the visible spectrum, black is basically the absence of color. The spectrum are varying wavelengths of light. For example, grass appears green because it's reflecting the wavelength of green light and absorbs the wavelength of the other visible colors. All of the absorbed light turns into energy, or heat.\n\nIn the case of black clothing, there are no wavelengths for light to bounce off of. As such, it absorbs all wavelengths and thus, creates more energy/heat."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
34xlmc
|
why is nickelback the butt of so many jokes?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/34xlmc/eli5_why_is_nickelback_the_butt_of_so_many_jokes/
|
{
"a_id": [
"cqyzu5n",
"cqyzxwr",
"cqz1fvj"
],
"score": [
7,
8,
2
],
"text": [
"Because they are pretty famous and, while their main songs aren't bad, they do sound similar to each other, so people call them formulaic.",
"Because they're not very good, generic pop with some metal painted over it. \n\n[At least two of their songs are exactly the same music with different melodies](_URL_1_)\n\nMost of their songs are about sex and drugs. The few that aren't have little lyrical creativity. \n\nThey regularly get booed off stage, and have stuff thrown at them. \n\nThe music is over-compressed, they have no dynamic range, and most of their music sounds the same. \n\nHere's what some professional music critics say:\n\n\"Brazenly consistent, if unimaginative.\" ––Rolling Stone\n\n\"Nickelback can now afford a little more time in the studio and a little more time to indulge themselves, and they turn out the same record, only slicker, which only highlights just how oppressively and needlessly sullen this group is.\" ––Allmusic\n\n\"Like all Nickelback releases before it, All The Right Reasons was made for all the wrong ones and follows all the formulas and cliche's you should be bored to death of by now.\"––Tiny Mix Tapes\n\n\"Nickelback are a gnarled, vulgar band reveling in their ignorance of the very notion of taste, lacking either the smarts or savvy to wallow in bad taste so they just get ugly, knocking out knuckle-dragging riffs that seem rarefied in comparison to their thick, boneheaded words.\"––Allmusic\n\n\n\nThe LA times summed it up well, \"Nickelback's music isn't for hipsters or music lovers, it's for people who don't want to have to think\". \n\n[Here's another good description in video form](_URL_0_). ",
"It's because people like to jump on the band wagon. Having a go at something which is popular to dislike often carries people until they actually think it's their opinion. So instead of not listening to it...which is what you do to music you don't like, people actually feel the need to attack it.\n\nJust look at the comment from HannasAnarion. Huge sweeping generalisations, which could be said about almost any band. It's annoying to think someone like that considers their opinion to be notable."
]
}
|
[] |
[] |
[
[],
[
"https://www.youtube.com/watch?feature=player_detailpage&v=PmTUW-owa2w#t=220",
"https://www.youtube.com/watch?v=Qs4tNeGyTyI"
],
[]
] |
||
ohl3s
|
polish reverse notation
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/ohl3s/eli5_polish_reverse_notation/
|
{
"a_id": [
"c3hbdeg"
],
"score": [
9
],
"text": [
"I'm assuming you are referring to Reverse Polish Notation\n\nOn paper, RPN is just postfix (operator after the numbers) arithmetic read left to right. \n\n2 + 3 becomes 2,3 +.\n\n3 * 5 + 70 becomes 3,5 * 70 +\n\nDo not get caught up with how it looks in this format, it is actually much simpler to think of it as you would have done it is grade school, with the numbers written over each other, and writing the operator to the left of the bottom number. Just remember that this comes last. Then you \"draw the line\" under it and get the answer. If you want to use that number again, you just write the second number, then the operator, then draw the line. Note: below I just put the operator after the number to avoid confusion of the order.\n\n3\n\n5*\n\n__\n\n15\n\n70*\n\n__\n\n85\n\nRPN is essentially worthless on paper, since you can just write the formula out in a more natural mathematical style. \n\nIt's implementation in HP calculators and some computer systems is the only reason to learn this. I will describe the HP system. \n\n\n The enter key replaces the comma in the linear notation, and the line break in the elementary school way. The enter key stacks the number you just entered into the next register, and then you input another number and perform the operation. The operation performed on the bottom 2 registers, and the one you type into is the bottom most register. (On most HP calculators, I think the graphing calculators do this a little differently). Once you do the calculation, the result is left in the bottom most register, for you to see, or use. On most, you can start entering a new number, and it stacks automatically, some you have to manually stack it. Refer to the user guide on that one\n\nUsing this type of entry, it is imperative to know your order of operations, the machine will not do them for you, but a familiarity with the equations you are using guarantees this. The benefit of this is that you can unambiguously tell the calculator what to do, and don't need to enter parenthesis. the downside is that you have to know how to do it. \n\nWhen faced with a long scientific equation, you must dissect it and chose where to start, and it sometimes isn't the left side. Knowing how to do this is just something that comes from practice, I highly recommend just sitting down with a TI and an RPN calculator (with at least 2 registers visible) and a math book, just plugging and chugging, and checking your answers. I did this with a one line display unit, it can be done if you have the time. It is the only way. "
]
}
|
[] |
[] |
[
[]
] |
||
ho8ct
|
What causes religion?
|
Just to get it out of the way, this isn't a philosophical question, I'm genuinely curious about the scientific reasons for the existence of religion.
Does it stem from a social need to belong? ...is it the result of a need for a parental figure past childhood? ...is it something our brain uses to rationalise things we can't explain? ...or is it something else?
I realise that my title isn't exactly descriptive, but I am having a hard time posing the question.
Basically, what is it about humans, that seems to make us pre-disposed to religious belief?
EDIT: Thanks for the responses so far! ...also had a conversation about this with my GF, and we both came up with the hypothesis that, from an evolutionary standpoint, religious belief would be favoured because it is pro, well, procreation, while non-belief causes us to question more, and propagate less. Possible?
EDIT the 2nd: I'm not attacking religion. I apologise for the controversy I've caused with my question. Also, I feel like I need to mention that when I say I am not attacking religion, I don't mean that I'm not attacking *your* religion. I simply mean that I am not attacking *any* religion. I am asking for an answer to my question that is based in evidence. Evolution, and natural selection. This is the point of view I ask my question from. I'm sorry if it has caused any confusion.
|
askscience
|
http://www.reddit.com/r/askscience/comments/ho8ct/what_causes_religion/
|
{
"a_id": [
"c1wz26h",
"c1wz2e3",
"c1wz46g",
"c1wz5le",
"c1wz5rh",
"c1wz704",
"c1wz7h4",
"c1wzbg2",
"c1wzcbv",
"c1wznv7",
"c1wzqpa",
"c1wzyna"
],
"score": [
4,
2,
2,
24,
11,
6,
4,
2,
22,
2,
2,
2
],
"text": [
"My psychology professor alluded to [superstition](_URL_0_) as one of the many causes.",
"You should read Darwin's Cathedral, I think it's a good read if you're interested in it. This in addition to some books on cultural evolution would probably give you a good idea. Fundamentally, the theory is that religion began just as a way to gain social cohesion. Something to bond over, have in common, etc. Basically just something to strengthen community ties and have a better functioning society. ",
"I'm in no way scientifically or philosophically trained, but I've thought of this many times before. I keep coming back to the same concept of \"the first seizure\". I ask myself, \"How did early people groups explain that?\".\n\nThey must have been frightened by the incident. But what was the cause? I believe it all stems from a fear-coping reaction. Although the seizure may or may not have resulted in an injury, it would comfort the group as a whole to have a concrete *reason* for the incident. Demon Possession? But at that early stage in our evolution (no religion yet...), how does one conceptualize a demon? It probably was more comforting to blame this seemingly random and chaotic event on a non-human being as to eliminate internalizing the 'blame-game' to members of the people group.\n\nThus evolves tales and myths from people groups around the world for countless generations. These tales explain the misunderstood medical, geological, meteorological, etc. occurrences that their meager developmental state could not process. It fills a fear-based \"comfort void\". When these people groups inevitably convene, similarities are noticed and these archetypes form the backbone for religion to form around.\n\nI'd love to hear anyone else's thoughts on this.",
"When you get an answer, let the rest of us know.\n\nNo, in all seriousness, this a nearly impossible question to answer. The problem is that we can certainly postulate explanations like those you give in your OP (and these are some of the more popular candidates, to my knowledge), and we can definitely demonstrate that some of those basic phenomena do exist--I think it's pretty well established that humans have a natural desire to belong to a group, and quite a bit is known about the psychology of rationalizing things that are logically incompatible (this is a bit out of my field though, so if anyone with more psychology expertise can let me know if/where I'm wrong, please do)--but it's nearly impossible even if you can provide support for the basic phenomenon to demonstrate that it is responsible for the complex cultural behavior (religion).\n\n**Edit: Folks, I know us science-y types tend to be non-believers and look down on the faithful for their beliefs, but can we leave the \"Fear of death\" stuff for r/atheism? That's not a scientific answer, and it doesn't belong here. This is the exact kind of issue the mods have been raising in recent weeks.**\n\nEdit2: I was of course, not careful with my wording. If there's legitimate scientific support for the \"fear of death\" hypothesis then by all means lets see the citations rain. I just saw that right off the bat like 3/4 of the first few posts were one line \"fear of death\" answers. If there's support for that that's fine. I just didn't want the thread taken over by people's personal disdain for religion.",
"\"Why we believe in God\" (_URL_0_) Hope this helps answer your question",
"Humans are hard-wired to find patterns in everything. To the primitive mind, the only pattern that humans could discern was that a more powerful being was controlling nature/their surroundings.",
"for the moment, the as yet empirically unexamined evolutionary answer to your question is [this](_URL_0_);\n\ntheir simple argument is that 'making causal links falsely' is favoured if the benefit of making true causal links outweighs the cost of making false causal links. \n\nif that condition is met, selection may favour a brain that makes causal links like mad, here there and everywhere because making the wrongs ones doesn't hurt as much as not making the right ones.\n\nquite compelling.",
"VS Ramachandran gave a very interesting lecture that I think pertains well to this:\n_URL_0_\nSkip to ~39 minutes for his talk.",
"Religion is caused by quite a few social issues but ultimately stems from four main causes:\n\n1) the ability to imagine\n\n2) respect for authority\n\n3) a need for understanding\n\n4) [confirmation bias](_URL_2_)\n\nI'll break each of these apart. For #1, it wasn't until Homo Sapiens that we find the first signs that hominids buried their dead but it is understood that some ability to study and use symbolism existed as early as [Homo Ergaster](_URL_0_). Once humans began building non-primitive tools and houses, it is easy to see the progression of more sophisticated [burial sites](_URL_1_) and this is really the major difference between homo sapiens and homo ergaster and this is the subject of lively debate. Still, respect for the dead did not originate until sufficient brain capacity and imagination/symbolism were available in the control mechanisms of the brain.\n\nFor number two, we see that most mammalian species have a pecking order but there are still many species in which the male, or sometimes the female, is dominant and only one of a group is in charge. Human authority often allows upward mobility and deference to authority is one of the mainstays of societies. This ability to respect people in authority and to respect people who know more than oneself is requisite for any religion to exist. By contrast, lions have authority but it is dominated simply by youthful and strong lions. Lions could not have a religion because the young often kill the elders and other young males. If humans had this type of pecking order, then institutions like churches would be impossible.\n\nFor our third point, and perhaps the most important, humans need to justify everything. We hate when someone dies \"in vain\" and we love the story of the soldier who defies authority to do \"what's right\" and wins the day. We search for meaning in everything and we demand answers, even when none are forthcoming. This leads to mythology and superstition. When something defies explanation, people look for mystical answers. We find hidden meaning in a lot of things which defy any sort of logic.\n\nOur last feature that causes religion is optimism bias. This may be a mind bender, but I hope to convey this idea. How many people do you know that have gone to Vegas or some other gambling place and lost? Now how many have won or broken even? Nearly everyone knows someone who has won or admitted to winning but not many people admit to losing because it's not as interesting. This tends to slant our views. Something similar happens that reenforces religions which is a confirmation bias: we believe something will have a certain outcome and when it does we admit to being right; when it doesn't, we ignore it or don't report it or simply say that we ignored important facts. You may recall that the world was supposed to end May 21st, 2011 and the reverend was incorrect. But that doesn't stop him or some of his followers: for some, this merely reenforces the notion that \"we may have the exact date wrong, but we know that it's close\". Confirmation bias is an interesting facet of human psychology and clearly influences how religions work and operate: great floods are ignored when a survivor child is found among the rubble because that child was saved by 'divine ordination' which conveniently ignores the deaths of hundreds of others.",
"*Faces in the Clouds: A New Theory of Religion*\n\nby Stewart Guthrie\n\nReview by Danny Yee\n\n > Attributing human or animal agency to events is an explanatory strategy which, while it sometimes fails, is in general extremely effective. \n\n > Since other humans and, after them, animals are the most important things in our environment, it is vitally important to take them into account when they are there — important enough that erring on the side of caution means accepting regular anthropomorphic and animistic \"errors\". \n\n > The result is that our conceptual and perceptual schemata incline us to animism and anthropomorphism. \n\n > The final chapter pulls these strands together to argue that religion *is* anthropomorphism. \n\n > ... *Faces* is the most convincing attempt at a unitary model I have seen. \n\n > It is, in any event, a significant contribution to the field: many have linked religion and anthropomorphism before, but none have done it so convincingly and few have explored the causal psychological mechanisms underlying the connection.\n\n\\- _URL_0_ - ",
"Here's one idea from [Sapolsky](_URL_0_), biological underpinnings of religiosity.",
"there is also apparently a predisposition in our brains for something like religion -- > [The God Helmet](_URL_0_)"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Superstition#Superstition_and_psychology"
],
[],
[],
[],
[
"http://vimeo.com/23450446"
],
[],
[
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2615824/"
],
[
"http://thesciencenetwork.org/programs/beyond-belief-science-religion-reason-and-survival/session-4-1"
],
[
"http://en.wikipedia.org/wiki/Homo_ergaster",
"http://en.wikipedia.org/wiki/Burial",
"http://en.wikipedia.org/wiki/Confirmation_bias"
],
[
"http://dannyreviews.com/h/Faces_in_the_Clouds.html"
],
[
"http://vodpod.com/watch/1729475-sapolsky-on-religion-via-boing-boing"
],
[
"http://en.wikipedia.org/wiki/God_helmet"
]
] |
|
27u2bz
|
could someone explain google seo, and what to look for when choosing a google seo package?
|
We run a +Size Online Clothing store, and are considering using _URL_0_ to find a Google SEO Package and promote our business, with so many packages available, We are unsure which to choose.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/27u2bz/eli5_could_someone_explain_google_seo_and_what_to/
|
{
"a_id": [
"ci4dxdr",
"ci4e0kk",
"ci4g74b"
],
"score": [
2,
2,
2
],
"text": [
"SEO means \"get your result to appear higher in the results for a search\". The closer to the top of the results list the more likely a link is to be clicked. Being at the top of the results list generates the most clicks.\n\nGoogle (and Bing) optimize the results that are returned for every search with the goal of presenting the most useful link in first position, the second most useful link in second position, etc.\n\nSo \"Search Engine Optimization\" (SEO) means \"figuring out how to change your web page, and change how that web page is embedded in the space of web pages to convince the search engine that it is more useful as a result than other options\".\n\nRemember that no major search engine will publish its exact system for generating page ranks. Everything that is known about how they work is derived from experiments, some occasional hints dropped by the Search Engine companies, and research published before Google became wildly successful.\n\nThe two biggest factors that apply involve the content on the page itself and how that content is structured.\n\nYou can find lots of advice on how to structure your page and your site to optimize the value it presents for various search queries. That involves things like including certain tags on the page, the ratio of advertising to content, the use of headers, etc. \n\nYou can also find lots of articles on how Google's Page Rank algorithm works (and by extension, how Bing works, etc.) These all involve the concept of \"link juice\" Page Rank is based around the idea that a page gains value based on having high-value pages link to it. A link from a tiny blog with 10 readers generates less \"link juice\" than a link from _URL_0_. Figuring out how to get high-quality links to your page is a huge part of what SEO optimization companies promise to help with. **Actually** getting high quality links to your page is really a function of your Public Relations team - most people who claim they can generate quality links are using techniques that Google doesn't like and if they detect them, they'll actually generate negative \"link juice\" (your rating will be worse than if you had done nothing).\n\nSpend a half-day researching this topic and you'll quickly figure out who the scammers are and who the reputable companies are. There are no magic bullets. There are no short cuts. Once you configure your pages and your site with best practices all the rest comes from hard work and PR.",
"I've never heard of Google SEO Packages but I can give you some information on SEO and PPC. \n\nSearch Engine Optimization includes free ways to optimize your website so that it ranks higher in search engines. For example, including popular search terms in your URLs, site titles, site copy, and meta tags makes your site more relevant in the \"eyes\" of the search engine. \n\nPay Per Click is a form of advertising that allows your site to appear at the top of certain keywords--for a price. You use a tool like AdWords to bid cents or dollars on certain keywords or combinations of keywords. If at any point your keywords are queried and clicked on, you then pay Google or Bing or whatever you had bid. \n\nMany companies outsource their SEO and PPC to marketing companies, but I would discourage you from using some faceless internet company over a company in a major city near you. Using a local company can help ensure you stay on top of your results and enable you to have meetings with the actual analysts doing the work as opposed to talking on the phone with customer service. \n\n\nSEO is not incredibly difficult to learn. There is a lot of literature online and in print that can help guide you through the process and save you some money. Good luck!",
"_URL_0_\n\nUnless you've followed the instructions in this guide, you're wasting your money on SEO work."
]
}
|
[] |
[
"Fiverr.com"
] |
[
[
"CCN.com"
],
[],
[
"https://support.google.com/webmasters/answer/35769?hl=en"
]
] |
|
3em58c
|
why are actors not allowed to drink alcohol in commercials right after drinking it/ doing drugs in shows?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3em58c/eli5_why_are_actors_not_allowed_to_drink_alcohol/
|
{
"a_id": [
"ctg847f"
],
"score": [
2
],
"text": [
"There are different laws for advertisements. In TV shows, drinking alcohol is generally an aspect or a character, or important to a scene, or something that isnt directly related to wanting to make you buy that alcohol. \n\nAdvertisement on the other hand, would want to make you buy alcohol in any way they possibly could. they dont care if they motivate people to become alcoholics as long as sales are being made. So, because of this, laws are made to lessen the potential effectiveness of advertising manipulation. "
]
}
|
[] |
[] |
[
[]
] |
||
17bpbq
|
why does water go down a plughole differently depending on which side of the equator you're on?
|
Or is this a myth? I remember hearing something about it ages ago. I was just wondering, if true, why it happens! :)
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/17bpbq/eli5_why_does_water_go_down_a_plughole/
|
{
"a_id": [
"c840pdp",
"c849b8x"
],
"score": [
21,
2
],
"text": [
"It doesn't\n\nWater goes down the plug hole depending on the design of the sink. The forces due to the side of the equator are tiny so have essentially zero effect on water in a kitchen sink or toilet.\n\nWhich side of the equator you are on can have an effect on water through the [Coriolis effect](_URL_1_) but only in large scales (like weather systems) or very special circumstances where you have carefully removed all other forces and kept the temperature constant ([as described in the 2nd paragraph on this part of the wiki](_URL_0_) )",
"I went to this little tourist trap in Quito that was supposed on the equator. They had a basin, and put it on one side, it would drain one way, then put it on the other side, and it would drain the other way.\n\nI was mildly impressed, until I took out my GPS, and say that we were nearly a half kilometer from the equator. The \"official\" line they draw was based on pre-GPS surveying, and was inaccurate.\n\nSo obviously, it was a trick, and it doesn't matter where you are."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Coriolis_effect#Draining_in_bathtubs_and_toilets",
"http://en.wikipedia.org/wiki/Coriolis_effect"
],
[]
] |
|
dr59c7
|
Did Viking armies have a military rank structure? If so, what was it, and who was in charge or above who?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/dr59c7/did_viking_armies_have_a_military_rank_structure/
|
{
"a_id": [
"f6fdb6r"
],
"score": [
27
],
"text": [
"The following is just a bit re-edited summary from my previous comment to the relevant question, [During the \"Viking Age\", how common was it for Danes, Swedes and Norwegians to become vikingr? Was this something many people did, or just a small group? What was the social class of the people who went? How did normal farmers in their society see them?](_URL_0_) plus some additions. \n\n+++ \n\nProvincial law books in all the three Scandinavian kingdoms (Denmark, Norway, and Sweden) from High Medieval Ages certainly stipulate a province or kingdom-wide royal naval conscription system, called *leiðangr*. According to these stipulations, free (in a legal sense) farmers in each district were required to provide with men, some weapons as well as armory, and further, a ship with sailing equipment in response to the royal summoning of the fleet. They also had to maintain such a district's ship with equipment under penalty of fines. Magnates (*lendmenn*) and lesser local officer (*årmann*) are commissioned to inspect the status of such provided weapons and ships regularly on the king's behalf (*Gulathing law*, Chap. 309), but it was not (only) they, but some conscripted farmers might well serve as a shipmaster when the king ordered them to do so under the penalty (*Gulathing law*, Chap. 299). Some thralls owned by someone in the conscripted district were also expect to board and to serve as cooks in place of their masters (*Gulathing law*, Chap. 299). A royal biography of Norwegian Kings dates the origin of such a royal naval conscription in the middle of the 10th century, but, recent scholars tend to disregard this later account as a literal evidence of kingdom-wide *leiðangr*, at least not as is stipulated in refined form in the extant manuscripts of the lawbooks. \n\nThen, how was the crew of the Viking ship usually gathered? While joint ownership of the ship among 'ship-fellows' were known from some runic inscriptions, Niels Lund, an expert of the military system of the Viking and Medieval Scadinavia, proposes that the fleet of the Vikings from the 9th to 11th century primarily consisted of military households (Old Norse *lið*) of various Norse chieftains (Lund 1993). Thus, even the large-scale Viking fleet like the Great Army those who were active across the English Chanel about ca. 870 was basically a scratch team of such diverse military retinues and often lacked the single effective military leadership, though some capable rulers like King Sweyn Forkbeard or King Cnut the Great of the Danes could at least temporarily control the large fleet under their auspice, I suppose. \n\nBoth contemporary and later sources agree that Scandinavian rulers had organized the elite military retinue like Cnut the Great's lithmen latest since ca. 900. While the 13th century Norwegian law of retinue (*Hirdskrå*) shows highly stratified ranks among the Norwegian royal military retinue (Old Norse *hirð*), in course of its transformation into the not so exclusively military nobility (Cf. Imsen 2000), we can discern some important officers among the royal retinue already in the 11th century. To give an example, skaldic poems, one of the only two Scandinavian contemporary textual sources from the Viking Age, sporadically mention the deed of the 'marshal' (Old Norse *stallari*) who was to be the foremost position among the retinue in *Hirdskrå* (Cf. Imsen 2000: 215). A skaldic poem was indeed composed and dedicated to *stallari* Úlfr who served King Harald hardrada of Norway around ca. 1060 (Steinn Herdisason, *Úlfsflokkr*). It is likely that some *stallari* like Úlfr acted as second-in-command among the royal military household, but we don't have almost no evidence on how non-royal military household of the magnate was organized during the Viking Age (though I assume not so different). \n\nReferences: \n\n* Hooper, Nicholas. 'Military Developments in the Reign of Cnut'. In: *The Reign of Cnut: King of England, Denmark and Norway*, ed. Aleander R. Rumble, pp. 89-100. London: Leicester UP, 1994. \n* Imsen, Steinar. 'King Magnus and his Liegemen’s \"Hirdskrå\": A Portrait of\nthe Norwegian Nobility in the 1270s'. In: *Noble and Nobility in Nobles and Nobility in\nMedieval Europe: Concepts, Origins, Transformations*, ed. Anne J. Duggan, pp. 205-220. Woodbridge: Boydell, 2000. \n* Jesch, Judith. *Ships and Men in the Late Viking Age: The Vocabulary of the Runic Inscription and Skaldic Verse.* Woodbridge: Boydell, 2000.\n* Lund, Niels. 'Danish Military Organization'. In: *The Battle of Maldon: Fiction and Fact,* ed. Janet Cooper, pp. 109-26. London: Hambledon, 1993."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/wiki/profiles/y_sengaku"
]
] |
||
3f2vl4
|
What is "modern sand" and when was it deposited on the sea floor?
|
I'm watching David Attenborough's "Life On Earth", circa 1979, and he says that a "thousand million" years ago, "modern sand" appeared on the sea floor in large enough quantities to allow burrowing life to evolve. What is this modern sand, how was it formed, and why did it only appear a billion years ago?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3f2vl4/what_is_modern_sand_and_when_was_it_deposited_on/
|
{
"a_id": [
"ctl306e",
"ctlmwzm"
],
"score": [
10,
2
],
"text": [
"Not sure why he says 1 B years ago, but he must be talking about the Cambrian substrate revolution. Essentially, before this event, seafloor life was centered around microbial mats, tight, firm films of bacteria, along with the fauna which depended on them and existed on top (and rarely under) of them. With the evolution of trilobites, worms, and other 'bioturbator' organisms, these mats were disturbed, and the anoxic, closed off environment under the mats was exposed to life. All the additional bioturbation led to looser substrate(modern sand, I suppose), and critically, a more 3-dimensional environment for seafloor life, allowing greater diversity.\n\nA source among many: _URL_0_",
"Not got the DVD available at the moment (packed in a box) but are you certain he's not saying 'mud and sand'?"
]
}
|
[] |
[] |
[
[
"http://www.geosociety.org/pubs/gsatoday/archive/sci0009.htm"
],
[]
] |
|
5s3stx
|
what happens to you if you sell something that says "not labeled for individual sale"?
|
My question is legal in nature. What power does the law give to producers of products that say "not labeled for individual sale". Would I be risking civil or criminal penalties selling such items? If so, why are these laws in place?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5s3stx/eli5_what_happens_to_you_if_you_sell_something/
|
{
"a_id": [
"ddc6302",
"ddc76e0"
],
"score": [
2,
6
],
"text": [
"You lose your contract with your distributor, and maybe get sued for breaching that contract.\n\nRetailers contract with lots of different distributors, who in turn contract with producers and manufacturers. If the manufacturer only wants its products sold in six-packs they'll be labeled \"Not for individual sale\" and its contracts with the distributor will stipulate that. The distributor's contract with the retailer will have similar language. So if the retailer decides to disregard the manufacturer's directives, the distributor either has to cut them off, or risk losing their contract with the manufacturers.",
"In addition to what u/rhomboidus said, there might also be legal penalties. The most likely scenario is with food products, where there are laws requiring labeling of all the ingredients, allergens, calories, etc. On some bulk purchases of individually wrapped items that are all the same, they put one label on the outside box but don't label each individual package of food. If a retailer decides to sell the individual packages, the consumer isn't able to get the legally mandated info about what's in the food from the packaging."
]
}
|
[] |
[] |
[
[],
[]
] |
|
3hr5qn
|
Why does TV/Film from the late 80s/90s often have such oversaturated colours?
|
I know I'm sailing close to the 20-year rule, but I'm pretty sure this applies to stuff made before 1995.
I've noticed that TV from the 90s often has this really...*odd* colour scheme; I'm not really sure how else to describe it. I'm talking about videos like [this](_URL_2_)(particularly the ident in the beginning) or [this](_URL_1_) or [this](_URL_0_) which appear to have the 'Colour' setting on the TV turned up to the highest setting. I've been told the word I'm looking for is *oversaturation*.
I was just wondering why oversaturation seems to be so prevalent in stuff from the 90s? Is it actually due to the film technology they had at the time, or was it just pure fashion?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3hr5qn/why_does_tvfilm_from_the_late_80s90s_often_have/
|
{
"a_id": [
"cu9xqb5",
"cua2kkl",
"cua4dd7"
],
"score": [
45,
24,
7
],
"text": [
"So, you may have better luck on /r/editors or /r/videoediting, but I'll take a stab at it anyway.\n\nActual oversaturation would mean you're compressing the color information at the top end. So, take [this](_URL_0_), and imagine everything getting squished toward the top. This will often also result in noticeable artifacting, as the differentiation between similar colors is lost.\n\nWhat you're seeing from video from the 80's/90's is probably the result of a couple of things. 1) Style. Experimenting with vibrant colorscapes was kind of more of a thing, especially in the 80's. (See the Saved by the Bell open.)\n\n2) Degradation. So... depending on what the original was shot on, how many formats it has gone through since then, and what you're watching it on, you're probably seeing a very different image than the original. An older example of this is very old music / voice recordings. You know how we think of them as being high pitched? That's only because they were recorded at a slightly different rate than they tended to be played back in later dubs. \n\nSome of that is simplified, maybe overly so. And some of that is guessing based on some half-remembered film school classes. But it's in the ballpark.",
"It's actually two different subjects. Both of them basically are basically trends.\n\nDeee Lite was born in the clubs of New York in the very late 80's - Early 90's. The club scene back then was full of bright colors, including neon. If you look at other club acts like Deee Lite, you'll see bright neon colors. Vanilla Ice, Black Box, C & C Music Factory, MC Hammer, all had bright or flashy colors.\n\nEven the grunge trend still had bright colors to it. Nirvana, the Red Hot Chili Peppers, Pearl Jam, Temple of the Dog all had one or multiple members that wore bright colors, not necessarily neon, but still bright.\n\nIf you look at [Heart Shaped Box by Nirvana](_URL_0_) you'll see both the bright colors and the saturation. \n\nMTV was incredibly influential at the time, I think more back in the 1990's than it is now. The musicians and seeing videos influenced style, and that style changed depending on what your preference in music was.\n\nThe Game of Thrones video looks really similar to [Xena Warrior Princess](_URL_1_). It's actually the first thing I thought of when I watched it.\n\nAs far as the saturation trend of the last 20 or so years, [this explains the editing process](_URL_2_) and why the saturation looks like it does.\n\n",
"Maybe try watching the same show on a period correct TV and see if it still looks over saturated."
]
}
|
[] |
[
"https://www.youtube.com/watch?v=etviGf1uWlg",
"https://www.youtube.com/watch?v=1osAbkUQmFY",
"https://www.youtube.com/watch?v=2fPgIIB67bw"
] |
[
[
"http://www.synthetic-ap.com/images/tg2wfmrgb.png"
],
[
"https://www.youtube.com/watch?v=n6P0SitRwy8",
"https://www.youtube.com/watch?v=Sb8l1iRehpw",
"http://priceonomics.com/why-every-movie-looks-sort-of-orange-and-blue/"
],
[]
] |
|
8ez2zc
|
How did the approximately four minute song become (somewhat) standard? Was it influenced by the needs of radio, or was it the other way around?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/8ez2zc/how_did_the_approximately_four_minute_song_become/
|
{
"a_id": [
"dxzk15y",
"dxzsff3"
],
"score": [
4,
2
],
"text": [
"You may like these previous answers. But these are not to discourage discussion here -- further questions, data, and debate are welcome.\n\n\"When did music shift from long, drawn out symphonies to the short songs of today?\" at _URL_2_ has answers from /u/joglaser , /u/erus , and /u/thesweetestpunch . This discussed history back centuries.\n\nSimilarly, \"When did hour long symphonies turn into short, three minute songs?\" at _URL_1_ has an answer by 3fox.\n\nFor some more recent factors concerning technology, you can see \"The standard duration of a pop song is about three minutes. Was it always this way? Why weren't songs longer or shorter?\", with a thread under _URL_0_ by thesweetestpunch. (If you go to the base of the discussion, there are several severely downvoted replies along the way; depending on your Reddit settings, these replies may cause this thread to be collapsed on you.)\n\nEdit to make it easier to copy and paste this in the future: \n\"When and how did ~3 minutes become the standard length of pop songs?\" at _URL_3_ ; check both replies by hillsonghoods.\n",
"In addition to all the fine answers collated by /u/scarlet_sage, I had a go at answering a [similar question here](_URL_0_) - make sure you read the follow-up too, as there was information in that I would have put in the original reply!"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/3o1cu3/the_standard_duration_of_a_pop_song_is_about/cvte86u/",
"https://www.reddit.com/r/AskHistorians/comments/30jhxd/when_did_hour_long_symphonies_turn_into_short/",
"https://www.reddit.com/r/AskHistorians/comments/33xe4y/when_did_music_shift_from_long_drawn_out/",
"https://www.reddit.com/r/AskHistorians/comments/6v1jtj/when_and_how_did_3_minutes_become_the_standard/"
],
[
"https://www.reddit.com/r/AskHistorians/comments/6v1jtj/comment/dlxeu64?st=JGGDCYLY&sh=343574e9"
]
] |
||
flbf8q
|
When you have an illness (flu, throat infection etc) does your immune system weaken since it is busy fighting or actually improves since it is active? Or none of the above? Thank you
|
askscience
|
https://www.reddit.com/r/askscience/comments/flbf8q/when_you_have_an_illness_flu_throat_infection_etc/
|
{
"a_id": [
"fkzq278",
"fkxrzpq",
"fkxudvf",
"fkxui6k",
"fkxxg3w"
],
"score": [
3,
19,
270,
5,
3
],
"text": [
"Immune system is stronger when the new illness is similar to the one you're currently fighting. \n\nIf the new illness is very different, then your immune system appears weaker in fighting the new one, and the new illness can take advantage of this. Interestingly, the immune system becomes more efficient in fighting the first illness when a 2nd different illness is encountered.",
"It's difficult to generalize since there are so many variables other than the disease itself that can effect how your immune system responds. Probably the only generalization that can be made is that the \"average\" person's immune system will work harder than it does at baseline to contain the disease. Whether or not it becomes \"stronger\" or \"weaker\" at the time largely depends on a wide range of preexisting factors pertaining to the individual's overall health. That said, if your immune system successfully fights off the disease, then it's generally safe to assume that your immune system will become stronger as a result. This is based on tons of high quality evidence showing that immunity is built over continual exposure to the environment. For example, a large study on polio that was conducted during the 1950's (if I recall correctly) found that poorer children tended to be more resistant than wealthier children. The scientists concluded that the poorer children had acquired more immunity through increased exposure to their environments, whereas the wealthier children tended to live more isolated and sterilized lives.",
"I see some people saying yes and this is not a supported statement. Your immune system is activated upon interaction with a pathogen or with the recognition of a non-self antigen. This means your entire immune system begins to rapidly expand and proliferate. At the beginning of an infection this is dominated by your innate immune system (complement, macrophages, dendritic cells, neutrophils, natural killer cells, ect). At this same time this is occuring T and B cells are interacting with antigen presenting cells in your lymphatic system. When a T or B cell interacts with its cognate antigen (the antigen that corresponds to its T-cell receptor or B-cell receptor) it undergoes a proliferative burst. B cells will create plasma cells and undergo somatic hyper-mutation. At this point the adaptive response overtakes the innate response and remains the primary response until; containment, clearance or host death.\n\n & #x200B;\n\nSo no, your immune system is not weakened as a whole. What does happen is the survival cytokines and other survival signals are sequestered by cells who have an advantage, such as the T or B cells who recognize the pathogen. HOWEVER other cells are still around and if you had your immune system recognize multiple antigens at a given time, they would all receive the same signal and compete for resources.\n\n & #x200B;\n\nInterestingly, this is why the theory that you can develop an allergy during an immune response exist and why some researchers are looking into using broad immune system activating events to combat cancers.\n\n & #x200B;\n\nTLDR; When fighting off an infection your entire immune system goes into overdrive. Once the adaptive immune system is fully operational it sequesters energy from other parts because it has so many things pushing its activation.\n\n & #x200B;\n\n\\*EDIT changed compliment to complement",
"Both, in a way.\n\nIt 'improves since it is active' in that the immune response engages several mechanisms to get the defenses up and make them more efficient. For example, the swelling and redness you see around a wound is due to the body directing more blood (and therefore more immune cells) into the site of injury. \n\nSimilarly, the whole reason 'flu-like symptoms' are so generic is that a good chunk of the symptoms is caused by the release of natural antiviral defenses - and as a rule of thumb, antiviral immune response is basically the Spanish Inquisition of immunology, which is why you don't want it running full tilt 24/7.\n\nOn the other hand, an infection stretches the budget for immune system. You can only put so many new blood cells through the pipeline per hour, and the old ones keep getting decommissioned even *without* anything else killing them. Then you also need to replace the cells where either side caused some collateral damage. All of that takes up raw material - energy, lipids, amino acids...\n\nEven a relatively mild infection means diverting some resources towards killing off the present threat rather than a potential one. On top of that, the defense mechanisms also have a cost attached. Fever is the most obvious example - it's running the metabolism overcranked, and shivering is trying to convert your muscle power into heat, which takes up some calories, and loss of apptetite is a fairly common sickness response - which means there's less energy to spare for training any immune cells to deal with any other issues.\n\nSo overall, it's improved in that it's primed to fight whatever thing is plaguing you right now, but weakened in that it doesn't have time to spare to deal with less immediate threats - that's why you get stuff like opportunistic infections.",
"Typically, yes fighting one infection will hinder the immune systems ability to fight another infection but its not based on weakened immunity. Rather, the immune system has to prioritize which threat to take care of. Infected cells and immune cells secrete chemical messengers called cytokines which instructs other arms of the immune system on what kind of threat it needs to fight. For example, fighting an intracellular pathogen (like a virus) requires a different set of tools/weaponry than fighting an extracellular pathogen (like many bacteria/parasites/fungi). The cytokine environment at the site of infection dictates which specialized troops the immune system needs to mobilize to fight the infection. \n\nNote that I'm simplifying it quite a bit here but importantly, the cytokine environment that mobilizes anti-viral weaponry tends to impair an anti bacterial response and vice versa. This is why viral infections by things such as influenza are often followed by secondary bacterial infections. \n\nTo avoid making this comment too long, see my comment below (within this comment thread) for more specific details."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
j4hks
|
trust funds
|
How do trust funds get established? How do they work? What exactly are trust fund babies?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/j4hks/eli5_trust_funds/
|
{
"a_id": [
"c292ear"
],
"score": [
2
],
"text": [
"A trust fund is basically a bank account with a sum of money in it. The interest on the account goes out as a check to the receiver, every month, for the rest of their life because the trust fund will keep generating interest forever. So trust fund babies are people whose grandparents thought they'd blow all the cash by the time they were 30 on expensive cars, cocaine, and clothes, so instead they choose to make the trust fund to slowly leak money to the child who then can't blow it all.\n\nSo if you are a trust fund baby, you might get a check for $2500 a month, for the rest of your life, for doing nothing. Wouldn't life be easy?"
]
}
|
[] |
[] |
[
[]
] |
|
5qga7s
|
why terminally ill liver cancer patients feel so drowsy?
|
Many years ago my father died from liver cancer.
I remember that the last days he was drowsy and sleepy. I didn't think much about that at the time. Maybe I thought that being so ill, the body was just giving up.
However, few months ago I read that this has something to do with the liver tyhat is not able to process correctly some chemical that is similar to benzodiazepine but I'm not able to find the source again.
Someone can explain me if there is a chemical correlation between drowsiness and a non functioning liver?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5qga7s/eli5_why_terminally_ill_liver_cancer_patients/
|
{
"a_id": [
"dcz0rhs",
"dcz21vj"
],
"score": [
3,
2
],
"text": [
"Likely it was the cocktail of drugs he was given towards the end. Was he on palliative/end of life care? Ativan, (Which is a benzodiazepine) Fentanyl, and Morphine (which are opiates/opioids) are frequently given which all cause drowsiness, and potentiate each other. \n\nEdit: also, our liver is what allows us to break down these chemicals in ways that lets us process them. If the liver isn't producing the enzymes used to process those chemicals they stay in the body longer, causing stronger effects. Which is why some drugs have warnings not to drink grapefruit juice while taking them...alternatively, people drink grapefruit juice and use other enzyme inhibitors to make certain drugs stronger. ",
"Well the liver is our body's chemical treatment plant if you will. It processes many harmful chemicals into other stuff that we can use. If the liver shuts down your body slowly can't handle the toxins anymore that build up in our system every day. Also if he got pain medication the liver could not longer process those either."
]
}
|
[] |
[] |
[
[],
[]
] |
|
1qezji
|
how can frozen dinners (like banquet brand) cost as low as 89¢ per box? is it even food?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1qezji/how_can_frozen_dinners_like_banquet_brand_cost_as/
|
{
"a_id": [
"cdc5o7y"
],
"score": [
4
],
"text": [
"I never heard of this brand, so I Googled it. The cheapest I was able to find was $1.65. Either way, it's cheap because it's small amounts of low-cost food -- corn, potatoes and low-quality meat. \n\nRounding: The whole thing weighs 9 ounces, so let's say each bit is 3 ounces. You can get a can of corn for less than a dollar and it's 3 servings, so a serving of corn is 33 cents. You can get a pound of potatoes for a dollar, so 3 ounces is less than 20 cents. The cheapest ground beef I could find was $4.50 a pound, so that's 84 cents. Total: $1.37."
]
}
|
[] |
[] |
[
[]
] |
||
8vu6ga
|
Is the nucleus of an atom a sea of quarks without clear boundaries between protons and neutrons?
|
I am aware of the quantum stuff that means we can't know exactly where the protons and neutrons are but that's not what I mean. Since both are made of quarks, ups and downs I think, are the quarks just all together in one big soup instead of being bonded to two others like in diagrams?
|
askscience
|
https://www.reddit.com/r/askscience/comments/8vu6ga/is_the_nucleus_of_an_atom_a_sea_of_quarks_without/
|
{
"a_id": [
"e1qat8f",
"e1qcwq3",
"e1qnmo8",
"e1qpgd7",
"e1qyaus",
"e1rwlmm"
],
"score": [
1482,
356,
143,
11,
46,
2
],
"text": [
"No, it’s more of a sea of nucleons/quasiparticles (nucleon pairs, alpha clusters, etc.). It’s not simply a homogeneous sea of quarks.",
"Color confinement of quarks suggests that there is very distinct clumping of them into hadrons. The idea of a nucleus as \"sea of quarks\" does not work in that scenario, as that tends to imply a certain level of freedom for quarks which does not actually exist. \n\n",
"There are predictions that as the nuclei gets heavier than around that of oganesson, the currently known heaviest element, the quarks will stop being bounded in protons and neutrons, and will form what is called up down quark matter. \n\nNuclei from udQM are thought to be stable, allowing for new stable elements beyond oganesson. \n\nYou can read more here: _URL_0_",
"How can you have a sea if there's only a handful of quarks?",
"Follow-up question. Does the nucleus have orbitals like electrons? ELI PhD in biochemistry",
"One thing that really messes with your idea of the proton is relativity. A bag filled with marbles and weighs similar to 100 marbles you would expect to be filled with marbles right? Well a proton is made up by quarks but 99% of it's mass comes from binding energy. You could say that the individual quarks are not really what makes up the proton. They each have a very insignificant mass and high kinetic energy, but when bound together in a system and you look at the center of momentum for the system the rest mass equals that of a proton. \n\nHow exactly those quarks bind together, I don't know. But if a quark stops being bound by that center and start interacting with other protons or neutrons the Hadron which it came from will no longer be a proton."
]
}
|
[] |
[] |
[
[],
[],
[
"https://phys.org/news/2018-06-periodic-table.html"
],
[],
[],
[]
] |
|
2aqxgn
|
How much matter (i mean like asteroids, random stars, etc) do we think exists in the space between galaxies?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2aqxgn/how_much_matter_i_mean_like_asteroids_random/
|
{
"a_id": [
"ciy0pii"
],
"score": [
10
],
"text": [
"The intergalactic medium, the stuff between galaxies, mainly consists of very hot ionised particles. This is basically atoms like hydrogen that are so hot, they are stripped of their electrons. This a plasma of charged particles that lie between galaxies. This gas can be pulled in by galaxies, which is one idea of how galaxies keep forming stars after they run out of hydrogen, by simply grabbing more hydrogen from around them. \n\nIt is thought that up to half the baryon if matter (the matter that isn't dark matter!) exists in between galaxies.\n\nIn terms of objects like stars, asteroids and planets, it is unlikely they have enough energy to escape the gravity of a galaxy. However, when stars interact with each other they can slingshot one or more of them with great speeds out of the galaxy. Some of these have been observed already I believe.\n\nImagine being on a star truly in the middle of space. You can't resolve any stars with your eyes, every bright point in the sky is a galaxy. Must be a pretty awesome sight :)"
]
}
|
[] |
[] |
[
[]
] |
||
72psmy
|
how does meditation improve mental stamina?
|
I've read that meditation can improve your mental stamina and I was wondering how exactly it does this. I'm a full time student and I spend a lot of time studying and doing flashcards to learn new material, but once I reach a certain point my mental energies are completely zapped and I can't bring myself to do anymore. I was wondering if meditation could help my brain last longer before throwing in the towel for the day.
I also read that meditation gives you the best results when it involves you actively focusing instead of just zoning out. If this is the case, will meditation simply drain even more of my mental stamina? I am already consciously controlling my thoughts for long stretches of the day when I attempt to memorize flashcards and solve problems, how is the focus you use in meditation different?
Just to be clear, my attention span and ability to focus on my studies are not deficient in any way. It takes me hours of flashcards to hit this wall (Also I do take breaks, get plenty of exercise and sleep, etc.). I am just looking for a way to improve my ability to focus and learn new information beyond how it is now. If possible I would love to see official articles regarding this subject, but any and all input would be greatly appreciated, thanks.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/72psmy/eli5how_does_meditation_improve_mental_stamina/
|
{
"a_id": [
"dnkgn2d",
"dnkhui0",
"dnkkt2w"
],
"score": [
35,
12,
2
],
"text": [
"I feel like the other two are too quick to jump on the placebo explanation.\n\nA better way to think about meditation that sounds less mystical is that you're training your brain to stop wandering and having too many thoughts at the same time. It's a real and documented effect, and it does wonders for eliminating negative thoughts and helps you focus (less noise)\n\nIt is easy to see why having a less noisy and distracted mind would alleviate the drain on your mental faculties.",
"Although meditation has several evidentiary benefits, with a long and colored past of scholarly investigation, it hasn't been shown to be more effective at producing the kinds of results you're looking for than focusing on any other single task for a long period of time.\n\nTo be blunt; exercising your ability to mentally focus helps you improve your ability to mentally focus. It doesn't matter if you're meditating or reading complicated material or building a boat in your basement. It's the practicing and exercising that gradually improve your ability. \n\nEDIT:\nSome scholarly sources of information on the topic.\n\n_URL_2_\n_URL_1_\n_URL_0_",
"Although you are looking to extend mental stamina, I’d offer than in my experience meditation does a great deal more than that. The best way I can describe it is like drinking liquid luck if you are a Harry Potter fan. It has this amazing effect that just makes things work out better. My interactions with others improve, I can stay calmer for longer, and yes, I can focus for longer periods of time because it relaxes my mind. Meditations allows the mind and body to release the stress that inevitably builds up in our lives, given clearer though and a more focused mind."
]
}
|
[] |
[] |
[
[],
[
"http://online.liebertpub.com/doi/abs/10.1089/acm.2007.7022",
"http://www.sciencedirect.com/science/article/pii/S0306987703001750",
"http://www.sciencedirect.com/science/article/pii/S1053810010000681"
],
[]
] |
|
9g1syj
|
Was there ever a time in the U.S. when an escaped slave could have taken refuge with a Native American tribe ?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/9g1syj/was_there_ever_a_time_in_the_us_when_an_escaped/
|
{
"a_id": [
"e61d0za"
],
"score": [
281
],
"text": [
"Slaves often took refuge in the swamps of the American southeast during the early decades of the nineteenth century (I would presume further back into the eighteenth century as well, though I know less about that history). It was not easy for slaveowners/catchers to track runaway slaves into Florida's swamplands, and groups of slaves often set up their own \"maroon\" communities there. \n\nAt other times, they might join an Indigenous community in the region. Most famously, the Seminole--one of the five major Indigenous groups in the southeast often referred to as the \"Five Civilized Tribes\"--had significant numbers of \"maroons\" as members of their community, but runaway slaves also joined up with groups like the Creeks. \n\nIn the late 1810s, American forces under the command of Andrew Jackson staged a campaign against both maroon and Indigenous communities in the southeast. They were forced to cede territory to the United States, and many of them were eventually removed to Oklahoma along the Trail of Tears. Maroons were often resold into slavery. As the region was brought under American control, it became more difficult for slaves to run away to the swamps and join Indigenous communities. However, not all of these communities were stamped out, and some of them managed to avoid persecution for decades.\n\nFor this comment, I primarily drew upon Daniel Walker Howe's *What Hath God Wrought: The Transformation of America, 1815-1848.* The first three chapters or so have some information on this. However, his book is just a summary of what other scholars have said about this topic--his bibliography and notes will be able to point you toward more in-depth works on the subject, if you're interested."
]
}
|
[] |
[] |
[
[]
] |
||
1102gz
|
why do we see rays of light going in different directions when there is a single light source in a dark area?
|
If you're looking at a light (say, the status light at the bottom of a monitor) in a place where it's otherwise completely dark, why does it look like there's rays of light going in other directions? I know that light goes in every direction from the source, but why can we see it when it goes in other directions?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1102gz/eli5_why_do_we_see_rays_of_light_going_in/
|
{
"a_id": [
"c6i4ddo"
],
"score": [
3
],
"text": [
"Reflections. Everything you can see is literally reflecting (or emitting) light."
]
}
|
[] |
[] |
[
[]
] |
|
43w52c
|
what led to the us policy of containment?
|
I understand the policy in itself, and how it was part of the ideological conflict of the cold war, but what historical events specifically led the US to adopt this policy?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/43w52c/eli5_what_led_to_the_us_policy_of_containment/
|
{
"a_id": [
"czleqtv"
],
"score": [
2
],
"text": [
"People in the US government were divided between striking a conciliatory tone with the USSR and a strategy of confrontation that eventually became containment.\n\nThe single event that most directly led to the adoption of containment was George Kennan, a diplomat in embassy at the USSR, writing what has come to be known as \"the long telegram\" which basically coalesced the views of the \"confrontation\" side of the argument into a coherent strategy (which was, basically, containment) and served to convince a lot of people in DC that it was the way to go, including the Truman administration. "
]
}
|
[] |
[] |
[
[]
] |
|
obred
|
How do retroviruses become endogenous?
|
I am really confused by the final paragraph of [this New Yorker article](_URL_0_):
> Villarreal predicts that, without an effective AIDS vaccine, nearly the entire population of Africa will eventually perish. “We can also expect at least a few humans to survive,’’ he wrote. They would be people who have been infected with H.I.V. yet, for some reason, do not get sick. “These survivors would thus be left to repopulate the continent. However, the resulting human population would be distinct” from those whom H.I.V. makes sick. These people would have acquired some combination of genes that confers resistance to H.I.V. There are already examples of specific mutations that seem to protect people against the virus. (For H.I.V. to infect immune cells, for example, it must normally dock with a receptor that sits on the surface of those cells. There are people, though, whose genes instruct them to build defective receptors. Those with two copies of that defect, one from each parent, are resistant to H.I.V. infection no matter how often they are exposed to the virus.) The process might take tens, or even hundreds, of thousands of years, but Darwinian selection would ultimately favor such mutations, and provide the opportunity for the evolution of a fitter human population. **“If this were to be the outcome,’’ Villarreal wrote, “we would see a new species of human, marked by its newly acquired endogenous viruses.”**
So I don't see the jump between defective genes for cell receptors and "newly acquired endogenous viruses". What am I missing? Are these defective genes caused by endogenous viruses? Would HIV become endogenous if it couldn't penetrate our cells?
|
askscience
|
http://www.reddit.com/r/askscience/comments/obred/how_do_retroviruses_become_endogenous/
|
{
"a_id": [
"c3fzums"
],
"score": [
6
],
"text": [
"Wow the author is jumping around on this subject. In general, one method of resistance is if the individual develops mutations in the receptor that the virus docks on to the point that the virus cannot dock on the host's cells. The virus needs to dock in order to be incorporated into the hosts cells. In this scenario, there will be a selection to resistance. This often happens over many many many generations. Unfortunately the virus can also adapt to the host and it is like a war of mutation with the virus often winning due to the higher mutation rate. This is the case with the flu virus and is why you need yearly flu shots. \n\nAnother method of resistance can come about when the population develops mutations in an endogenous proteins that the virus needs to replicate. In this scenario, the population will have the virus but the virus will not be able to propagate throughout the population of resistant individuals. Again, there would be mutations in the virus that would favor the the mutated individuals proteins and due to the higher mutation rate may lead to no advantage. Also, the population may have lower fitness due to the mutated proteins. A good example of this is sickle cell anemia. Heterozygotes for the gene are resistant to Malaria but with two copies of the defective gene results in Sickle cell Anemia resulting in the gene being kept in the population for resistance at the cost of Homozygotes being ill. Remember, if one individual has the genetic magic bullet it would not result in the population having it unless everyone is infected and dies suddenly and you have an island effect. \n\nBasically, it will not be endogenous if it cannot infect you via the mutated receptor. But can be endogenous if it infects and cannot replicate and is incorporated into the genome (and it helps if it can convey some sort of advantage with the incorporated population). "
]
}
|
[] |
[
"http://www.newyorker.com/reporting/2007/12/03/071203fa_fact_specter?currentPage=all"
] |
[
[]
] |
|
myx58
|
What is the most current description of a vacuum?
|
I'm aware that a vacuum in space is not truly empty, as shown by the Casimir effect and other experiments. What exactly is a vacuum then, and does this affect how physicists view real matter?
I'm particularly interested in something I read that described a vacuum as being nearly infinitely dense and that real particles exist only when an excitation in a field "knocks" the particle out of the vacuum. Here is the quote I'm going off of:
> In the 1930's Dirac proposed that the vacuum was a near infinitely dense sea of particles in which all of the possible quantum states were filled. Matter as we know it, is what exists in quantum states above the vacuum. When a particle is knocked out of the vacuum, it leaves a hole called an anti-particle. Strong electromagnetic fields can effect the interactions of electron positron pairs which alter the observed electromagnetic field. The effect is called vacuum polarization and it has been experimentally observed.
Is the above quote correct?
|
askscience
|
http://www.reddit.com/r/askscience/comments/myx58/what_is_the_most_current_description_of_a_vacuum/
|
{
"a_id": [
"c34zk2s",
"c34zk2s"
],
"score": [
7,
7
],
"text": [
"The best current description (and this describes everything we've observed in terms of high energy physics) is that spacetime is filled with quantum fields. It turns out that quantum states of these fields correspond to a number of particles with particular properties. e.g. we may excite the electron field to have 1 particle with a particular momentum.\n\nExcitations of these fields (i.e. particles) behave and interact with other excitations of this and other fields according to very particular rules. We use experiments like LHC to continually verify this.\n\nWe are also able to generate these rules from even simpler rules/models (representation theory of Lie algebras, and gauge symmetries). Some of these rules have issues and we've postulated the existence of additional fields (Higgs field(s), supersymmetric fields) to explain them. The LHC will help us better understand the existence/behaviour of these fields.",
"The best current description (and this describes everything we've observed in terms of high energy physics) is that spacetime is filled with quantum fields. It turns out that quantum states of these fields correspond to a number of particles with particular properties. e.g. we may excite the electron field to have 1 particle with a particular momentum.\n\nExcitations of these fields (i.e. particles) behave and interact with other excitations of this and other fields according to very particular rules. We use experiments like LHC to continually verify this.\n\nWe are also able to generate these rules from even simpler rules/models (representation theory of Lie algebras, and gauge symmetries). Some of these rules have issues and we've postulated the existence of additional fields (Higgs field(s), supersymmetric fields) to explain them. The LHC will help us better understand the existence/behaviour of these fields."
]
}
|
[] |
[] |
[
[],
[]
] |
|
ofpjx
|
why do some states get to vote first? who decides?
|
...for primaries ~~and general elections~~. It seems unfair.
[corrected by kouhoutek]
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/ofpjx/elif_why_do_some_states_get_to_vote_first_who/
|
{
"a_id": [
"c3guvez"
],
"score": [
6
],
"text": [
"First, all states vote on the same day for national general elections.\n\nSecond, primaries are not a part of government...they are for two private clubs to decide who they want to support in the eventual election, and they get to make up whatever rules they want.\n\nSo fair doesn't enter into it. The parties like the current system, because weak candidates usually bow out quickly leading to a consensus and unity that will help them beat the other party. If this means Iowa gets a bigger voice than California, so be it."
]
}
|
[] |
[] |
[
[]
] |
|
76y95d
|
how does an inverter increase voltage from 12v to 240v instantly?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/76y95d/eli5_how_does_an_inverter_increase_voltage_from/
|
{
"a_id": [
"dohjvs3"
],
"score": [
2
],
"text": [
"Hi! \n\nAn inverter, first and foremost, converts from a direct current input to an alternate current output, rather than converting from any lower voltage to a higher voltage. The latter is simply an advantageous side effect or features in most inverters. \n\nThis DC-to-AC conversion is achieved using anything from a simple, rapidly-moving mechanical switch in concert with smart circuit design (which results in a [square AC wave](_URL_1_)), to complex circuitry with semiconductors, transistors, diodes, FETs, ICs and software-level control to output a very clean [sine AC wave](_URL_4_), similar to what you get out of the power socket. \n\nNow... \n\nThe voltage step-up is achieved usually using a variety of ways, but these can be distilled into two main groups: a DC-voltage step-up, or an AC-voltage step-up. \n\nThe former is achieved using what's seen in your PC/notebook power supplies: a [DC-DC converter](_URL_3_), which is a little bit of semiconductor (usually a diode or transistor) together with a capacitor to step up the voltage. The actual circuit design would make this an ELI20. This is a [fairly basic one.](_URL_0_)\n\nThe latter is somewhat simpler: using the principles of electromagnetic induction, the already-converted AC current is sent through a copper coil wrapped around one side of a square iron ring. On the other side is another copper coil with more windings, which means the voltage is stepped up. This coil-ring-coil arrangement is called a [transformer](_URL_2_). \n\nSo let's say we have a 12 V DC current that's perfectly converted to AC. This current is sent through the first coil which has 20 coils. The coil on the other side has exactly (240/12) × 20 = 400 coils. \n\nThroughout all this, one equation is king: P = V × I, or power equals voltage times current. Meaning to say whenever the voltage goes up, the current goes *down*, and vice versa. In an ideal scenario, power is conserved throughout the inverter. \n\nIn real life, actually, some power is lost to the environment as heat, or mechanical energy in other components, so the output power will actually be slightly *less* than the input power. \n\nHope this helps. "
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/File%3ABoost_circuit_2.png?wprov=sfla1",
"https://en.wikipedia.org/wiki/Square_wave?wprov=sfla1",
"https://en.wikipedia.org/wiki/Transformer?wprov=sfla1",
"https://en.wikipedia.org/wiki/Boost_converter?wprov=sfla1",
"https://en.wikipedia.org/wiki/Sine_wave?wprov=sfla1"
]
] |
||
t3b91
|
Do muscles use the fat nearest them for fuel?
|
For example, if I want to slim my arms - doing arm exercises will build muscle in the arms but will it also be more likely to target the fat stores in the arm for fuel?
Apologies for my lack of scientific sounding vocabulary...
|
askscience
|
http://www.reddit.com/r/askscience/comments/t3b91/do_muscles_use_the_fat_nearest_them_for_fuel/
|
{
"a_id": [
"c4j6egw",
"c4j6eqh",
"c4j6fi4",
"c4j6i9q",
"c4j6jpj",
"c4j6qf7",
"c4j7b3o",
"c4j7xu4",
"c4j9791",
"c4jangd",
"c4jbcfh",
"c4jdilm",
"c4jdm5q",
"c4jewqk",
"c4jezr5"
],
"score": [
1050,
97,
11,
30,
4,
2,
3,
2,
7,
6,
11,
5,
5,
5,
2
],
"text": [
"No.\n\nMuscles cannot use fats directly. They are broken down into glycerol and fatty acids by the liver, which in turn are transported via the blood stream to the muscles.",
"It's called spot reduction and it's pretty much a myth.\n\n_URL_0_\n\n_URL_1_",
"No sir, this is why spot reduction isn't possible (or else you'd be seeing a bunch of guys of different shapes and sizes with a six pack!) ",
"The very simple answer is no...the fat is broken down into energy and used that way. The other question of where it goes is based around that as muscles grow, the fat begins to be redistributed, for space reasons. Think about how if you wear a really tight belt, you can make fat deposits above and or below, because there is not as much space for the fat to deposit in the area of the belt. Your body does this, naturally, around muscle growth. That being said, you can still have muscular abs and fat deposits...It can all depend on your body structure.",
"What you are talking about is spot-loss, and the human body doesn't work that way unfortunately. Your fat usually ends up coming off in the opposite of the order it went on. If your body likes to store fat in the stomach, it will probably try to hold onto those fat stores. \n\nTry looking around /r/Fitness or /r/loseit ",
"I know i'm going to be corrected, and I welcome it, but your body breaks down nutrients as part of the digestion process and nutrients and fuel enter the blood stream to then be absorbed by the cells that need them. Once the easy access to energy is expended, your body will start breaking down its stored fat and muscles to fuel itself (depending on what it needs). Working out a specific area of the body may alter the appearance quickly, because the muscle tone in that area increases, but the body stores fat in specif places (different places for men and women) and if your body fat level is high those areas will firm up first. _URL_0_ link discusses a study that suggest spot targeting doesn't work. You need to get your overall body fat down.\n\nTLDR: working out your arms will tone the muscle around them, and make your arms look more fit. But it is unlikely that your arm muscles will spot target the fat around your arms. You need to get your overall body fat down to do that.",
"e.g., situps do NOT remove fat from your stomach, just build the muscle under it.\n\nYou have to lose weight (jogging and other means) to see the muscles you build to get a ripped abs.. ",
"TL;DR on ALL of those comments:\nNo, fat burning is a global process, but muscle strength can be targeted.",
"It's generally regarded as a myth, but I'm aware of a paper from a few years ago that shows that there is an effect like you describe.\n\n_URL_0_",
"Topical fat reduction is possible, but not with exercise. You can inject isoproterenol and apply forskolin, yohimbine and aminophylline topically to achieve targeted fat loss. Although it won't be the same as excercise, there are results.\n\nSee: _URL_0_\n\nPlease note that there may be side effects to using these products and you might want to consult your doctor first.",
"There's alot of comments about it being an \"even breakdown\" of fat everywhere (thus no spot reduction), but nobody's saying why. The signals for Triglyceride release from adipose tissue are more global as hormones like increasing epinephrine and cortisol will activate the enzymes (e.g. Hormone Sensitive Lipase) necessary for lipolysis (fat breakdown) of triglycerides into free fatty acids (ffa). Because these are global signals, it happens to adipose tissue globally. The uptake of free fatty acids is greater in muscles that are actively working, because this temporarily increases the number of transporters (FAT) bringing them in. But they are taking the ffa from the blood regardless of where those ffa originally entered the blood (adipose in your arm or adipose in your leg).\n\nAlso, arm exercises are unlikely to burn much fat anyway as the primary fuel source for short duration exercises is anaerobic glycolysis (carbohyrdate fuel source). Carbohydrates (glycogen/glucose) and fats (ffa) are used to maintain ATP levels (energy molecule for processes in the cell) needed to do the work (and any other processes require energy after the work). Any extended exercise (preferably endurance but anaerobic intervals can also work) will increase the relative percentage of fats as a fuel source. A greater intensity of exercise will increase the percentage of carbohyrdates used, and although the relative percentage of fats is lower the total energy cost has increased (and so has the amount of fat used). If you want to slim your arms, endurance exercise is best but will actually result in slimming everywhere (for the previously mentioned reasons).\n\nReferences:\n1. Me - M.S. Exercise Physiology\n2. Brooks, Fahey, Baldwin - Exercise Physiology: Human Bioenergetics and Its Applications (getting older but still a great resource)\n\n",
"Muscle can store lipid ectopically (within the cell-even though it should be stored in the adipocyte). However most cases of intramyocellular lipid are associated with inflammation, insulin resistance and obesity. Interestingly, endurance trained athletes can store lipid in myocytes in close proximity to their mitochondria, the organelle responsible for turning fatty acids into ATP (energy), according to analysis by electron microscopy, potentially indicating intramyocellar lipid trafficing. So this would mean on a cellular level, lipid can be used by muscle under certain conditions.\n\nBut to answer your question on the whole tissue level is that fatty acids secreted by adipocytes can be used by muscle, however mostly for signaling or under inflammatory conditions, not in the situation you are thinking of. So basically if you're looking to tone fatty areas, reduce your calorie intake and increase your calorie burning. Sounds simple right?\n\nSource: years of studying metabolism...",
"Nope, spot reduction for weight loss is a myth. Please join us at /r/fitness! ",
"You do have intramuscular triglyceride (IMT or IMAT) that your muscles do use immediately, but these fat stores are found between muscle cells, not on between the muscle and the skin, which is the adipose tissue you are talking about trying to slim. That's called spot reduction and it's not possible, but yes your muscles do have small amounts of local fat that they can utilize briefly before need the hepatic fuel the others poster's have described. So the answer is yes, muscle cells use fat near them briefly, but no it can't be used to tone a specific region",
"No such thing as \"spot training\""
]
}
|
[] |
[] |
[
[],
[
"http://www.exrx.net/WeightTraining/Myths.html",
"http://examine.com/faq/how-do-i-lose-fat-around-my-belly.html"
],
[],
[],
[],
[
"http://www.acefitness.org/fitnessqanda/fitnessqanda_display.aspx?itemid=341"
],
[],
[],
[
"http://www.ncbi.nlm.nih.gov/pubmed/16985258"
],
[
"http://www.ncbi.nlm.nih.gov/pubmed/8697059"
],
[],
[],
[],
[],
[]
] |
|
1aubbp
|
Why are there different ways of measuring greenhouse gas emissions?
|
I've been doing some research and I've noticed that sometimes the data is presented as strictly the number of kilotons in the produced and other times by GDP, metric tons per capita. I was wondering why the different ways of presenting the data and why there seems to be a disparity when comparing the same country by actual production versus in relation to GDP
|
askscience
|
http://www.reddit.com/r/askscience/comments/1aubbp/why_are_there_different_ways_of_measuring/
|
{
"a_id": [
"c90uxzp"
],
"score": [
2
],
"text": [
"It probably has to do with the context. When speaking in contexts of individual impacts (gas-powered cars, electricity usage, etc.), it makes sense to use per-capita measurements. When doing other work, it may be more convenient to use total numbers. Without addressing each paper individually, that's about the best I can tell you.\n\nDiscrepancies probably arise from different data sources. Emissions data can be a bit uncertain at times, given that cars vary in gas mileage, power plants vary in efficiency, and different governments and other institutions vary in how they report emissions data. Unfortunately, I think emissions data will always be a bit uncertain, for these reasons. But again, without seeing individual papers, that's the most I can say for sure.\n\nIf you want hard numbers that are easy to quantify, you can look at the [actual atmospheric concentration](_URL_0_) of carbon dioxide, and its trends over time. These measurements will be very consistent globally because carbon dioxide mixes in the atmosphere so well and is so stable in the environment."
]
}
|
[] |
[] |
[
[
"http://www.esrl.noaa.gov/gmd/ccgg/trends/global.html#global"
]
] |
|
3ptxaw
|
Is there a theoretical minimum size for a living cell?
|
I know that mycoplasma and rickettsia are among the smallest cells known, but is there a theoretical size smaller than these below which a cell could never be viable? What is the limiting factor?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3ptxaw/is_there_a_theoretical_minimum_size_for_a_living/
|
{
"a_id": [
"cw9g5zj",
"cw9m0la",
"cw9n0lr",
"cw9ofdk",
"cw9oz0b",
"cw9pjll",
"cw9pw7x",
"cwa2lb5"
],
"score": [
81,
903,
302,
8,
7,
6,
5,
2
],
"text": [
"I'm by no means an expert in the field, but I'll give it a shot: \n\nI would think the limiting factor for organism size is likely based upon genomic size - the cell has to be large enough to fit the genome within it, in addition to all the proteins, enzymes and structural components of the cell. In the example of mycoplasma, it's genome is estimated to be about 580 kilobases long (tiny) and encodes for ~ 480 protein products. \n\nMycoplasma is a good example to consider, because it has evolved to have such a reduced genome, it doesn't have genes for cell walls or amino acid synthesis. It contains very few genes for nucleic acid and fatty acid synthesis. Basically it must acquire many required biochemical and metabolic products from its external environment or host cell, living as a parasitic cell. \n\nI suppose a cell could physically be smaller, to an extant, than this and still be viable - but I think it is unlikely, as metabolically mycoplasma and similar organisms would have no motivation to be any larger than they need to be - it would be a waste of energy to produce mass that is unnecessary for cell survival. \n\nConsidering that mycoplasma already has such a reduced genome, it is likely that anything smaller would have to be similarly (or even more so) parasitic and gather energy sources efficiently from a host organism. While I wouldn't say its impossible, my guess is that mycoplasma and similar organisms are about the smallest viable cells that exist. \n\nAnyway, I think its a great question and hope to hear from some commenters more educated in the field. \n\nedit: [source](_URL_0_)",
"An interesting answer from a physics perspective was given by Schrodinger in \"What is Life.\" He begins by asking why atoms are so small, by which he means why are organisms so large compared to atoms. The answer he gives is that life requires \"exact physical laws.\" If you don't have enough atoms, statistical fluctuations will be too large for life to develop. ",
"[NASA Office of Planetary Protection](_URL_1_) - Size Limits of Very Small Microorganisms: Proceedings\nof a Workshop\n\n > Following the report of possible microfossils ranging in length from 10 to 200 nm in the martian meteorite ALH84001, NASA’s Office of Space Science requested that the National Research Council’s Space Studies Board organize a workshop to provide a forum for discussions of the theoretical minimum size for microorganisms. The Board formed the Steering Group for the Workshop on Size Limits of Very Small Microorganisms, which convened a workshop on October 22-23, 1998 of leading experts in fields relevant to this question.\n\nAlso see: [Size Limits of Very Small Microorganisms: Proceedings of a Workshop.](_URL_0_ )\n\n > Consensus was reached by Panel 1 participants on the following major points, assuming free-living cells with conventional biochemistry:\n\n A minimum of about 250 to 450 essential genes are required for viability.\n The minimal viable cell diameter is expected to lie in the range of 250 to 300 nm.\n The number of ribosomes required for adequate genome expression is a significant constraint on minimal cell size.\n\n > If, however, the requirement for conventional biochemistry and genetics is relaxed, especially with reference to primordial or exobiotic self-replicating systems, the possibility of much smaller \"cells\" must be considered, such as those envisioned in the single-polymer model.\n\n\nEdit: added link to original NASA page",
"There was a radiolab recently about mega viruses. The emerging hypothesis seems to be that viruses may have evolved from fully alive bacteria, but, as parasites often do at a larger scale, they gave up some of the features needed to live independently, to the point that they no longer meet the criteria we've come up with for something being alive. They aren't big enough to contain the essential equipment to be alive, so that must be roughly the practical limit for how small life can be. ",
"According to Lehninger Biochemistry (a well-researched biochemistry textbook), the minimum size of a cell depends on how many molecules and organelles the cell needs to survive. The maximum size depends on diffusion; cells need to be small enough so that the molecules that they need (such as oxygen, for us) can reach the entire cell.\n\nI don't really know anything about tardigrades, but I tend to think of them when I think of incredibly tiny organisms. Does anyone know how they stand up to mycoplasmas?",
"It's usually a ratio between surface area and volumevolume. Go to small and you don't have enough volume to house the reactions needed to maintain the membrane wall. Go too big and you don't have enough transporters to feed the internal. Area and volume are related through a cubic, so you reach asymptotic limits fairly cleanly ",
"There is a bacteria that lives as an endosymbiont within the cells of cicada, Hodgkinia cicadicola. It has a genome a third the size of mycoplasma and has 169 ORFs (sequences that resemble genes). What cells give up as they get that tiny are genome size and metabolic functions. They have to live as parasites inside the cytoplasm of another cell to supplement metabolism. Think of plasmids though. Probably started out this way but gave up their membranes. I guess they aren't even technically alive at this point though. Still, they're free floating foreign DNA replicating independently inside the cytoplasm and many still have metabolic functions. ",
"PhD in Microbiology here. \n\nChris Kempes provided some energetic insights into taxonomic tradeoffs related to growth and metabolism and constrains traits that are important for size:\n\n_URL_0_\n\nThere are strong differences between eukaryotic and prokaryotic cells, as they invest different fractions of their metabolism on their growth. \n\nGenerally, the smallest known prokaryotes are similar in size and also possess the smallest observed genomes, which are assumed to be close to the minimum required to live alone (independent from other organisms).\n\nTLDR: Genome size (including a minimum set of genes for basic cellular functions) and associated cellular structures (eg. ribosomes) determine the lower boundary "
]
}
|
[] |
[] |
[
[
"https://microbewiki.kenyon.edu/index.php/Mycoplasma_genitalium#Genome_structure"
],
[],
[
"http://www.ncbi.nlm.nih.gov/books/NBK224747/",
"http://planetaryprotection.nasa.gov/summary/verysmall"
],
[],
[],
[],
[],
[
"http://www.pnas.org/content/109/2/495.abstract"
]
] |
|
aj3cn9
|
Right now it's dark most of the day and freezing cold here in Scandinavia. What would my Viking ancestors be doing on a typical day this time of year?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/aj3cn9/right_now_its_dark_most_of_the_day_and_freezing/
|
{
"a_id": [
"eetc6zx",
"eeuf4lx"
],
"score": [
67,
16
],
"text": [
"I have an *ancient* answer on a slightly broader question that gets into activities: [How did people in medieval Scandinavia survive winter?](_URL_0_)\n\n~~\n\nMedieval Scandinavian saints, by and large, perform similar miracles to their continental counterparts: helping the blind to see, the lame to walk, and people with pneumonia to breathe. But some of them also provided an additional service: reversing frostbite. Excavated graves at sites where armies are known to have overwintered also suggest the physical toll of northern winters. But at the same time, the methods medieval Scandinavians developed to adapt to their climate proved fundamental to integrating the territory firmly--irreplaceably--into the reviving European economy and political sphere.\n\nThe primary means for keeping warm on an individual level in the Middle Ages was fur. As early as the 8th century, rulers from southern Scandinavia intent on extending their territory northward began extracting payment/tribute from the Sami people who populated the Finland/Russia area in furs. As the European economy perked up, more and more furs ended up traveling south with merchants. In return, Scandinavians imported luxury church goods, cloth (even cloth-manufacturing centers import cloth in the Middle Ages), and above all grain from England. Although Scandinavians grew their own crops for consumption, the supplements from England allowed population growth in the north to occur along with a similar explosion on the continent. Archaeologically, we can see that the extent and sophistication of agriculture in Scandinavia increases dramatically in the 11th-12th centuries.\n\nThis development coincides with events to the north and east: more powerful groups in Russia were cutting off Scandinavians' access to the richest fur-producing regions like Karelia. But Scandinavians adapted--and made themselves essential to the continent. Medieval people tried their best to build up supplies of food to last through the winter, and William Chester Jordan's study of medieval famines suggests that by the 14th century some regions were regularly storing up enough food to survive one year of bad harvest without unleashing a famine. Nevertheless, people needed something to store up that would last, and also to acquire new food when they didn't have storage (as in cities). And Scandinavia became, in general, where medieval Europe got its preserved fish.\n\nCod was of course plentiful to catch off the coasts. But the Arctic climate was also perfect, as it turns out, for *drying* fish for preservation. Local salt mines also allowed fish to be preserved via salting. So Scandinavia's dried cod and salted herring not only fed its native population through the winters, it also went south and fed the growing continental cities.\n\nFarmers could not *farm*, per se, in the winter, but there was always work to be done with repairs, hunting, and so forth. We know from excavation of army overwinter camps that, already in the days of Viking raids, people would spend winters in craftwork like metalsmithing. There was also more time for games and playing. Ice skates and skis are ancient as an efficient mode of winter transportation, but the earliest references to ice skating as leisure come from the 12th century. From a bit later, the 16th century, there are descriptions of ice skating races. And there are plenty of medieval illuminations of, you guessed it, snowball fights!\n\nLight for crafting and dice would perhaps have been less of a problem, or at least less of an economic problem, in Scandinavia than to the south. Oil for lamps was readily provided by fish and seal oil, which was another key export for the region.\n\nAnd--*crucially*--they spent winters caring for livestock. In fact, thanks to the more or less ready supply of dried fish and the import of grain from England, feeding livestock over the winter was almost more of a challenge than feeding people. In fact, the Norse settlements of Greenland didn't even both growing domesticated crops to feed themselves (although they seem to have picked and eaten local berries). They devoted their energy to producing hay to feed their animals through a winter. \n\nBuckland et al. argue that the Greenland settlements' reliance on domesticated livestock, rather than learning from their contact with North American emigres how to travel further into the ocean to hunt bigger and better whales, proved catastrophic. A series of bad harvests meant the livestock starved, and the settlements were abandoned by the end of the Middle Ages. But in the 12th century, the settlers were still supplying Scandinavia with precious walrus ivory and falcons, which the Scandinavians then traded southward. \n\nAnd then, of course, there were the Scandinavians who found an alternate solution to the long cold winters. Birgitta Birgersdotter was one of the richest noblewomen in 14th century Sweden, with six children surviving to adulthood, significant charity work in her local community, a profitable and influential position in the household of Queen Christina, and an inheritance deep enough to fund the establishment of a continent-spanning monastic order. In other words, she had it pretty good up north. But once her husband died, Birgitta went on permanent pilgrimage to Rome. She spent the rest of her life there--except when she traveled on pilgrimage to the even warmer Near East.",
"First and foremost, they would do what Viking Age people did every day, nearly all of them, at every opportunity: **spin wool.**\n\n**Spinning wool** to create thread for weaving was the single most time consuming work in a Viking Age household. Everybody, save for the smallest children and the most respected men did that in their free time, and less capable people (cripples, seniors, children, unmarried older women) were specifically tasked with it.\n\n**Gathering firewood.** This was the second most time consuming work. Heating a VA hut with fire was fairly inefficient, but necessary for survival. This required near constant trips to gather firewood (especially brushwood), peat, animal dung, etc for the fire. A long lasting settlement would soon strip its local forests of all non-essential wood (that was not necessary for building, or for sale). This necessitate longer wood-gathering trips as well as local firewood trade.\n\n**Weaving -** it took the work of 7 spinners to provide woollen thread for one weaver, but almost every household had a weaver (usually the wife, but men and children could weave as well). During winter, weavers would usually work together in a dug in pithouses that were otherwise used for storage. Cloth was woven, cut, sewn into clothes and older clothes repaired in the winter-time. It was also obviously done year-round, but moreso in the winter/fall.\n\n**Repairs** \\- a typical VA household would gather a long list of miscellaneous tools, and gear to be repaired, or replaced. Axes, knives and sickles to be sharpened, hoes handled, shovels steeled, baskets repaired, cauldrons tinkered, animals treated if they were ailing, etc\n\n**Brewing Ale** \\- it was a year round activity, usually taking a few weeks between batches, but in the winter it was ramped up due to greater caloric needs of the people. VA ale was not like modern beer, it had weak alcohol content but high caloric content. It could be described best as \"sourdough drink\", that could be also thickened to make a porrige-like meal.\n\n**Preparation for house repairs** \\- no building or repair was done in the winter, as it would risk too much exposure and the building materials of the day would work poorly in sub zero conditions. However, raw materials could be prepared in advance. Shingles could be split , clay could be exposed to crumble (freezing and thawing repeatedly), coniferous trees would be bled and de-branched to create resin/sap infused wood.\n\n**Art** \\- long time spent indoor would be utilised to decorate everything from jewellery to everyday items in elaborate patterns. This resulted in a curious trait of Viking art, the so called \"horror vacui\" - fear of empty (unused) space. Confined to the indoors, and with a limited number of items to decorate, the craftsman (or more often, a bored amateur) would cover an item completely in an elaborate pattern leaving almost no empty space.\n\n**Entertainment** \\- numerous archaeological finds prove that the VA people owned and used a wide variety of musical instruments (from rare lyres to simple flutes), and music was a competitive sport in itself. So was singing, or rather sung poetry (melo-declamation). Some forms of it called for elaborate kennings (metaphors) and following a precise meter. It was also a competitive pastime, even up to including boastful or mildly insulting \"poetry battles\".Games of various kind were also popular, among them dice and hnefetafl (a game similar to checkers) are the most known, but numerous others existed, some of which we have only vague clues (like single game pieces). Last but not least, sex and procreation was a winter pastime for a couple stuck at home.\n\n**Religion and spiritual life** \\- we have very little information about it, but we know from the sagas that *Jól* happened in winter, and was the time where *Jólnir* (one of the incarnations of Odin) came to visit,the faithful (mentioned in *Skáldskaparmál*, ), and other gods were invoked then. Over time, it was slowly replaced by Christmas, but we know that in the late Viking Age the two holidays were celebrated side-by-side ( Hollander, M. Lee (Trans.) (2007). *Heimskringla: History of the Kings of Norway* )\n\n \n\n\nAnother thing: I would greatly recommend to you to see the **Alone in the Past Project**, about an archeologist/reenactor surviving winter in a medieval house, living a 9th century life. Of course, actual VA people would not dare live by themselves but functioned as a family/village, but the principles of everyday tasks needed for winter survival are the same."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/413h9n/how_did_the_people_in_scandinavia_live_during_the/cyzqq23/"
],
[]
] |
||
2ykw3s
|
Why does the time of solar noon shift from month to month?
|
I thought Greenwich Mean Time was synced to Earth's rotation (I know leap seconds were recently abandoned), but I've noticed the time of solar noon shifts up to 10 minutes throughout the year, how does that happen?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2ykw3s/why_does_the_time_of_solar_noon_shift_from_month/
|
{
"a_id": [
"cpaldcc",
"cpalmid"
],
"score": [
6,
2
],
"text": [
"Mostly because the Earth's orbit around the Sun is not a circle. As the Earth spins on its axis during a day, it travels through space around the Sun, so it has to spin more than 360° from solar noon to solar noon. When the Earth is near the Sun (January), it is moving through space faster than it is when it is far from the Sun (July), so the amount it has to spin to get the Sun back to due south is different.",
"Can you site a source for leap seconds being abandoned? I've found several proposals to abandon them, and the arguments from both sides of the issue, but from what I've found no decision has been made."
]
}
|
[] |
[] |
[
[],
[]
] |
|
9p4tgt
|
How accurate is the new Assassins Creed game to classical Greece?
|
[deleted]
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/9p4tgt/how_accurate_is_the_new_assassins_creed_game_to/
|
{
"a_id": [
"e7z2b5v"
],
"score": [
3
],
"text": [
"Not discouraging further answers, but [this thread](_URL_0_) may be of interest to you. "
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/9nla1e/i_am_a_historian_of_classical_greek_warfare_ask/"
]
] |
|
2vqcnl
|
what exactly happens when a light bulb burns out? why is it that when i shake a burnt out light bulb, the filament is always disconnected such that it rattles?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2vqcnl/eli5what_exactly_happens_when_a_light_bulb_burns/
|
{
"a_id": [
"cojzlwt"
],
"score": [
4
],
"text": [
"_URL_0_\n\nThe filament burns out, breaks in the middle form heating and contracting or gets too think in a spot and melts through. \n\nThe support wires don't get hot or deteriorate, so they still hold the ends of the now split filament wire, so it rattles when you move it. "
]
}
|
[] |
[] |
[
[
"http://i.imgur.com/kIJWVgs.jpg"
]
] |
||
1yzrsq
|
Why are copper salts like CuSO4 blue while copper is red?
|
Why does the color of Copper change so much when it reacts to salts like CuSO4, CuNO3, etc?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1yzrsq/why_are_copper_salts_like_cuso4_blue_while_copper/
|
{
"a_id": [
"cfp7ioi"
],
"score": [
4
],
"text": [
"Because the absorption bands correspond to electronic transitions between orbitals.\n\nChanging what an atom is bound to will change the energy level differences. More specific to metal coordination complexes, one can analyze metal complexes via [crystal field theory](_URL_0_). Again, interaction with ligands can change the crystal field splitting energy, Δo in the case of octehedral complexes, and Δt in the case of tetrahedral complexes. This alters the energy level difference, and therefore the absorption band.\n\nChanging the oxidation state of your metal also changes the _available_ electronic transitions."
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Crystal_field_theory"
]
] |
|
5yzrfg
|
How did European explorers react upon discovering that people in Indonesia, a very far removed area of the world, adhered to the same religion as their immediate neighbours in the mashriq and maghreb?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5yzrfg/how_did_european_explorers_react_upon_discovering/
|
{
"a_id": [
"deuwztn",
"dev6d16"
],
"score": [
7,
15
],
"text": [
"Can you clarify what you mean by explorers? Explorers in the 16th century \"Age of Exploration\" on the ocean are a different beast than 13th century land explorers like Marco Polo. Either way, I would argue that 13th or 16h century they didn't react with as much much surprise as you're anticipating; Europe did communicate with between Asia and Africa prior to the Age of Exploration. [Check out Sanford's interactive Silk Road website](_URL_0_).",
"I think one thing to bear in mind might be that, unlike the Americas, Europeans had a general idea of the existence of Indonesia long before they themselves had travelled there. They wouldn't have been totally ignorant of the region when they first arrived; at the very least, they'd travelled to India by sea a few decades previously. Indonesia might be far-removed from Europe but it's not so far-removed from India that trade and communication were impossible between them.\n\nOn the other hand, understanding of foreign religions was a little confused at this point; Europeans knew about \"Saracens\" of course (i.e., Muslims; Muslims were mostly treated as a monolith as far as I'm aware), but early Portuguese visitors to India apparently managed to mistake everyone who wasn't Muslim for Christians.\n\nSo, on the one hand, it's possible that it made perfect sense to them that if Muslims were in India as well as the Middle East (and everything in between), there'd also be Muslims further east in Indonesia. It's also possible that they had knowledge from Indians of what was to be found there. On the other hand, knowledge of the world was so confused (as another commenter mentions, Prester John — the myth that there was a great Christian kingdom somewhere in Africa) that it seems to me they'd have no reason to doubt that Muslims might be anywhere and everywhere."
]
}
|
[] |
[] |
[
[
"http://virtuallabs.stanford.edu/silkroad/SilkRoad.html"
],
[]
] |
||
1zmiey
|
If a child were never explicitly taught to walk, would he/she naturally develop the skill?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1zmiey/if_a_child_were_never_explicitly_taught_to_walk/
|
{
"a_id": [
"cfuzu7u",
"cfuzvts",
"cfuzybb",
"cfv0w6o",
"cfv10pb",
"cfv1x70",
"cfv21oo"
],
"score": [
84,
11,
21,
9,
5,
2,
2
],
"text": [
"Genie learned how to walk and nobody ever taught her. She's more of a linguist disaster but she didn't know much of anything when child services took her. You should check out her story. It's heartbreaking at first but it gets better.",
"We moved from walking on our knuckles a while ago. Animals that walk on their knuckles (like apes) have different features physically than naturally biped animals. In humans, our pelvis is more narrow and serves to support our internal organs. Our rib cage is less bowled out unlike apes, where the ribs are used to support the organs and allow for easier range of movement for the arms.\n\nThere are other anatomical differences, like the ratio of our legs and arms, the structure of our feet and toes, and other things. These structures and adaptations over time make walking on two legs for humans easier and preferable (ie. less likely to have chronic pain, easier locomotion). ",
"I don't think most children are \"explicitly\" taught. They see adults doing it and try to mimic the act. This is probably why any feral child would walk on all fours. They mimic animals that they see doing it. I have also read the evolution of the human pulvis has made it rather inconducive to walking on all fours. ",
"Humans do not learn to walk. Its a natural part of their development just like crawling. As soon as a kid is strong enough to support their weight on their legs, they will walk.\n\nOther cultures that keeps their kids on their backs when they are young plop their kids on the ground when they are big enough, and they just walk. There is nothing learned about it.",
"Walking is the result of all the stages that came before it. During the progression, they build muscle from one stage to the next and the nerves system matures. \n\nWhen put on their tummy, babies will try to keep their head up, this works the upper body and neck. They also start kicking, working the legs. Eventually they make it onto all fours and this turns into crawling. After crawling for awhile, working all four limbs, they start to climb/pull-up on objects. They then learn to stand without support, then it's just a matter of time before they make the first step.\n\n- BA in fatherhood",
"There is a family in Romania or Russia (I cannot recall) that was very isolated and only walks on all fours. They were being used for a lot of studies related to this very question, unfortunately I don't have any more information than that. Does anyone know what i'm talking about and have a source?",
"A child starts its development of movement early in the womb, starting from the 7th week and peaking at 15 to 17 weeks when neurological wiring is being developed. I remember from class that babies have the basic walking motion already written in their cerebellum around this time and can even walk on the walls of the womb. When a baby is born its muscles are simply not developed enough to hold its weight! This is seen in more mammals.\n\nWhen it is not taught to walk, it will either try to mimic others or learn in a process of succes and failure."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[]
] |
||
7dlwx5
|
why does the electricity in some cars get cut off when starting the engine?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7dlwx5/eli5_why_does_the_electricity_in_some_cars_get/
|
{
"a_id": [
"dpyomgn",
"dpyp5og",
"dpypjtu"
],
"score": [
6,
8,
2
],
"text": [
"There are two sources of electricity in a car. The battery, and the alternator. \n\nWhen your engine is off, the battery provides power to the accessories. This does drain the battery, which is why leaving your lights on overnight might kill your battery.\n\nWhen you turn your engine on, the alternator both powers your accessories and charges the battery, using power out of the engine to do so.\n\nWhen you're turning your car on, it shuts off the accessories so that the battery is dedicated to starting the car. Once the car is started, the accessories come on via the alternator.",
"The starter motor draws a lot of current, enough current to reduce the voltage output from the battery. Since electronics sometimes do wonky things when operated at lower than necessary voltage, it's better to just disconnect them for a couple of seconds while the car starts.",
"The battery is being used to forcibly crank the engine over. This isn't a trivial thing to do, as the air in the cylinders is resisting the starting motor, so it takes more than a little electrical oomph to do it. More going towards turning the engine over means less available for other electronics in the engine."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
t6u75
|
what is euler's constant?
|
It is starting to appear more and more in the math I am doing. I understand that pi is the relationship between a circles circumference and diameter. Is there something similar that e describes? Is there some way to think of it other than a random number slightly larger than 2.7?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/t6u75/eli5_what_is_eulers_constant/
|
{
"a_id": [
"c4k1juy",
"c4k1yi9",
"c4k270e",
"c4k2nh2",
"c4k2psl",
"c4k2qh1",
"c4k667q"
],
"score": [
15,
3,
8,
3,
2,
2,
2
],
"text": [
"Take (1 + 1/n)^n\n\nAs n gets larger and larger, the total gets closer and closer to e.\n\nIt's not as intuitive as pi, but that might help.\n\nExamples: \n\n* (1+1/2)^2 = 1.5^2 = 2.25\n\n* (1 + 1/100)^100 = 1.01^100 = 2.7048138294215260932671947108075\n\n* (1 + 1/1000000)^1000000 = 1.000001^1000000 = 2.7182804693193768838197997084544\n\n* e = 2.7182818284\n\n\nMore: _URL_0_",
"This is not really intuitive, but if you think about it for a bit it is pretty neat, and it isn't hard to remember: \n \ne is the number such that the derivative of e^x is e^x . That is, if you draw the line y = e^x, the slope of the tangent line at any point x is e^x . \n \n \nLook on the wiki page that Mason11987 pointed to and read the section Applications:Compound Interest if you want to get a \"feel\" for what the number \"means\" and why it is used so much in math and engineering. \n \ne also has a part in one of the coolest equations in mathematics: \n \ne^pi*i - 1 = 0",
"Suppose an account starts with $1.00 and pays 100 percent interest per year. If the interest is credited once, at the end of the year, the value of the account at year-end will be $2.00. What happens if the interest is computed and credited more frequently during the year?\n\nIf the interest is credited twice in the year, the interest rate for each 6 months will be 50%, so the initial $1 is multiplied by 1.5 twice, yielding $1.00×1.52 = $2.25 at the end of the year.\n\nCompounding quarterly yields $1.00×1.254 = $2.4414..., and compounding monthly yields $1.00×(1+1/12)^12 = $2.613035...\n\nIf there are n compounding intervals, the interest for each interval will be 100%/n and the value at the end of the year will be $1.00×(1 + 1/n)^n.\n\n[Here it is in a chart.](_URL_0_)\n\nFrom [wikipedia](_URL_1_).",
"The function y=e^x is the unique solution to the equation y' = y (I guess you've started calculus). So it comes up a lot in mathematics.\n\nIt's not an answer you would give to a 5 year old but the question isn't one a 5 year old would ask.",
"Another useful property of e - the antiderivative of 1/x is ln|x|",
"[This article](_URL_0_) explains the topic extremely well.",
"Imagine you have a very fast car and a nice clear road marked with distance markers.\n\nAt the 1 mile marker, you decide to play a game. You're going to make your speed match your distance travelled. You start at the 1 mile marker doing 1mph, and slowly step on the gas, so at 1.5 miles you're doing 1.5mph, at 2 miles doing 2mph, at 100 miles doing 100mph and so on. Always matching your distance to your speed.\n\nYou can see that if you plot your distance travelled against the time, it will eventually explode.\n\nAnd what's the name of the function describing this? It's \"x = e^t \", that is, your distance (x) is the magic number e raised to the power of the time (t) you've traveled. More intuitively, you'll e-fold (multiply by 2.7) your distance covered for every additional hour.\n\nAt 0 hours you've traveled e^0 = 1 miles, after 0.693 (=ln 2) hours, you'd be at 2 miles, and after 1 hour you're at e^1 (=2.72-ish) miles. And after just 10 hours you'd be over 22,000 miles away, nearly the whole way around the earth! \n\n[Technically, I've explained that x = e^t is the solution to the differential equation dx/dt = x]"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/E_%28mathematical_constant%29"
],
[],
[
"http://upload.wikimedia.org/wikipedia/commons/7/7f/Compound_Interest_with_Varying_Frequencies.svg",
"http://en.wikipedia.org/wiki/E_\\(mathematical_constant\\)"
],
[],
[],
[
"http://betterexplained.com/articles/an-intuitive-guide-to-exponential-functions-e/"
],
[]
] |
|
z7yu9
|
How long would a laser pointer travel in space before dissipating that you could no longer see it?
|
What the title says. How far would laser light be visible from the origin in space? (For sake of argument lets say that it is pointed in a direction that would not intersect any physical interstellar objects.)
|
askscience
|
http://www.reddit.com/r/askscience/comments/z7yu9/how_long_would_a_laser_pointer_travel_in_space/
|
{
"a_id": [
"c62bryq"
],
"score": [
4
],
"text": [
"First, some assumptions:\n\nYou're using a green (532 nm) laser pointer which can output 5 mW of power. The aperture is 3 mm in diameter, giving a minimum beam width of 532 nm / 3 mm * 180/pi = 0.010 degrees before diffraction becomes a problem. A real laser pointer probably isn't this good, but it's a decent starting point.\n\nI'll define \"visible\" as 90 photons hitting the 8 mm pupil over a period of 1 ms ([summary of the paper this comes from](_URL_0_)).\n\nTo solve the problem, you need to find the maximum range at which at least 90,000 photons per second strike a circle 8 mm in diameter.\n\nEnergy carried by a photon is h c / lambda, where c is the speed of light, lambda is wavelength, and h is the Planck constant. I like Joules and Watts, so I'll use h = 6.6261e-34. The energy carried by one photon at 632 nm is 3.1431e-19 J. A Watt is 1 Joule per second, so 5 mW is 1.5908e+16 photons per second.\n\nThese photons are spread roughly evenly across the laser's beam width, so if you divide the number of photons per second hitting the eye by the total number of photons per second emitted by the laser, you'll get the ratio between the area of the pupil and the total area illuminated by the laser at this range.\n\n90,000 photons per second / 1.5908e+16 photons per second = pi .004^2 / pi R^2\n\nR, the radius of the illuminated area, is 1682 meters. Almost done...\n\nThe rest is a bit of easy trig. Right angle triangle with one edge extending from the laser pointer to the pupil, another edge at a right angle to the laser-pupil line, and a known angle (0.005 degrees, half the beam width). Tangent of 0.005 degrees = 1682 / distance, **distance is 19274 km**. Halfway around the world if you like comparisons."
]
}
|
[] |
[] |
[
[
"http://math.ucr.edu/home/baez/physics/Quantum/see_a_photon.html"
]
] |
|
4jmqlz
|
why is it so hard to stay awake when we're sleepy?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4jmqlz/eli5why_is_it_so_hard_to_stay_awake_when_were/
|
{
"a_id": [
"d37wql5"
],
"score": [
3
],
"text": [
"Because your brain and your body want and need to go to sleep. So they're trying to go to sleep regardless of whether or not you're in a situation where you should be sleeping or not. You need sleep to survive and your body is more concerned about survival. "
]
}
|
[] |
[] |
[
[]
] |
||
1ojnbh
|
Are animals eyes affected by onions like humans?
|
Would your household pet have irritated eyes by being in the same room while you're cutting an onion?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1ojnbh/are_animals_eyes_affected_by_onions_like_humans/
|
{
"a_id": [
"ccsmaur"
],
"score": [
6
],
"text": [
"Not the most prestigious source, but definitely simple and accurate: onions burn your eyes because [a gas gets released from them that turns into sulfuric acid after contact with water.](_URL_0_)\n\nSince the eyes are just as sensitive in nonhuman birds and mammals, and definitely watery enough for acid to form, I would assume that they'd experience the same effect."
]
}
|
[] |
[] |
[
[
"http://chemistry.about.com/od/chemistryfaqs/f/onionscry.htm"
]
] |
|
2ftx0j
|
what's the purpose of the mysterious slash at the end of urls?
|
Example 1: type "reddit" in Google. Reddit will obviously be the first result, and you will see the address indicated as _URL_0_. Why "/"?
Example 2: go to the Reddit's homepage, _URL_1_ (notice there is no slash). Now, while there, copy the address from your address bar and paste it somewhere else - a slash will be added at the end of the URL. Why?
Example 3: open this link: _URL_0_ (notice the slash). When the website loads, the slash will be gone. Why?
Example 4: if you hover with your mouse over a link with a slash at the end of it, such as in examples above, in the bottom left part of your browser you can see the address this link is supposed to take you to. However, no slash will be included. Since the slash is part of the domain, why does it not show there?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2ftx0j/eli5_whats_the_purpose_of_the_mysterious_slash_at/
|
{
"a_id": [
"ckco90d"
],
"score": [
2
],
"text": [
"The slash is to identify the last child as a directory.\n\n_URL_1_ does not have a slash, because it is a page not a directory, but _URL_0_ has a slash because it is a directory. In most cases, any file with a \".\" after the last slash(the only place a dot should be) in the URL will not end with a slash, and all others URLs (except unlabeled files) will have a slash at the end."
]
}
|
[] |
[
"www.reddit.com/",
"www.reddit.com"
] |
[
[
"reddit.com/r/AskReddit/",
"reddit.com/index.html"
]
] |
|
dms38w
|
i just read about gravity traveling at the same speed as light and i'm still confused.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/dms38w/eli5_i_just_read_about_gravity_traveling_at_the/
|
{
"a_id": [
"f54buyi",
"f54ecmm",
"f54edob",
"f54fz3o",
"f54m5ex"
],
"score": [
6,
58,
35,
2,
2
],
"text": [
"Imagine a stick that’s one light year long. If you stood on one end and pulled on the stick, it would take time before someone on the other side of the stick felt that pull. So if you pull, and then drop the stick and leave, by the time that person feels the pull, you could be gone and somewhere else",
"Imagine a big heavy ball in the middle of a rubber sheet.... if the sheet breaks and the ball falls through the bottom, then the rubber sheet will take time to \"spring back\" up to a normal flat plane... That doesn't happen infinitely fast..\n\nThe same thing with gravity which is really just a warping of the local space/time fabric.. if something changes in the fabric some distance away from you , it takes time for the change in that fabric to reach you...",
"Don't think of the speed of light as the speed of light. We call it that for historical reasons, but that speed is not unique to light. A better way is to think of that speed (299,792,458 meters per second) as the cosmic speed limit for *everything.* That means nothing in the universe can go faster than that, and nothing with mass can ever reach that speed. It's the speed of information and causality. Once you think of it from that perspective, it becomes a little easier to understand. Since *nothing* can travel faster than that speed, changes in a gravitational field must also obey that speed limit.",
"The speed of light is really more \"the speed limit of the universe\". Things that have no mass, like force fields, can travel this fast. The electromagnet (light) force and gravity react at that speed. But everything else is moving too. So the gravity force between the sun and earth is moving in the direction of a straight line between the two. But in the 8 minutes that it takes the gravity to travel the 93 million mile distance, the earth has moved a bit. So there is a little but of lag.",
"As for your edit \"being pulled to a point where something was, but isn't there anymore\". From the Blue Marbles perspective the object is there. The fact that it's not there anymore is only something we're aware of because we are capable of processing time. But to an object it's not capable of processing time, there is no past or future for it. There is only now, and the now that it knows has that object there. This probably is a bad way to explain it."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[]
] |
||
34mmqt
|
if animals have far greater hearing capabilities then us, do they go insane when we play loud music in a confined area?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/34mmqt/eli5_if_animals_have_far_greater_hearing/
|
{
"a_id": [
"cqw5a76"
],
"score": [
3
],
"text": [
"Its not like they can hear things louder, its that they can here things in a wider range of frequencies. Like when you take that hearing test at your doctors, they can hear more of the low stuff and the high stuff, past where you start and stop hearing them. However, with the way their ears are usually shaped, noise is a bit louder, but more focused, depending on where the notice is coming from and if their ears can articulate (like a horse)."
]
}
|
[] |
[] |
[
[]
] |
||
1emo9q
|
on windows 64-bit, why do i see program files and program files (x86), and what is the difference?
|
I'm also a bit confused about when I download certain programs if I should get the 64 or 86 version, wouldn't 86 be more "power", or are these 2 completely different things?
EDIT: Woo, front page! Thanks for the knowledge!
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1emo9q/eli5_on_windows_64bit_why_do_i_see_program_files/
|
{
"a_id": [
"ca1plsm",
"ca1pup2",
"ca1pyud",
"ca1qajj",
"ca1qeuo",
"ca1qk9v",
"ca1r3ob",
"ca1ttu6",
"ca1v4ic",
"ca1vqvq",
"ca1vtgo",
"ca1xnh8",
"ca24l5i"
],
"score": [
10,
5,
513,
3,
86,
31,
8,
4,
3,
3,
2,
2,
2
],
"text": [
"The x86 programs are 32-bit. It's a backwards compatibility thing. Given the opportunity, always get 64-bit programs for a 64-bit operating system, if possible. They are less prone to errors. Most programs will work with a 64-bit OS, with the exception of drivers - you need to have the correct versions for each type.",
"The (x86) folder is for 32-bit applications, which (generally) can address up to 4GB of your system's RAM.\n\nThe non-(x86) folder is for 64-bit applications, which can address (theoretically) 2^64 bytes of your system's RAM.\n\nIn most cases, the 64-bit version is the better choice, assuming you have a 64-bit processor and a 64-bit operating system.\n\nMost installers will take care of the folder organization for you.",
"Using \"x86\" to denote 32-bit programs is an old homage to the Intel 8086 processor, but it is a bit of a confusing name to non-savvy users.\n\nProcessors can execute programs by either processing 32 bits at a time, or 64 bits at a time. If you have 64bit Windows, your computer can process both 32 and 64 bits at a time, so when you have a choice you could download either the 64 or 32, but 64 would be recommended.\n\nx86 isn't more powerful than x64 because an x86 processor can only handle 32bits of information at a time (the number is confusing).\n\nNow in general, a 64bit computer can be more powerful than a 32bit computer, this is due to the amount of RAM a 64bit computer can support (random access memory, its where your computer puts stuff while it's working on it, sorta like how you pull files out of your filing cabinet and work on them on your desk).\n\nProgram Files (x86) is where Windows stores all the information for the 32bit programs it has installed, to answer your title question.",
"Broadly speaking, when it comes to Windows, there are two main processor architectures, and their names/designations date back to the capabilities of the original Intel 8086 processor, which was first made in the 1970s. These two architectures are x86 and x86-64. x86 is 32-bit and x86-64 is 64-bit. Seems simple so far.\n\nBut there can be some confusion about this, because x86-64 often gets shortened to x64. Somebody can easily be tricked into thinking that x86 is better than x64, but the reality is that you should almost always choose x64 versions of your software if you have the option.",
"In this case, \"x86\" shouldn't be read \"times 86\", it should be read literally as \"x [i.e. the letter 'x'] eight six\".\n\nThink back to high-school algebra when you were taught that in an equation \"x\" can stand for any number. It's exactly this sort of usage. What it means is that these programs are compatible with \"old\" Intel CPUs, which were named:\n\n* 8086\n* 80286 (usually called just 286)\n* 80386 (usually called just 386)\n* 80486 (usually called just 486)\n* 586 (actually it was never called that, they called it the Pentium)\n\nSo from this pattern you can see why those processors are called \"x86 class\".\n\nThe CPUs from the 386 onwards were 32-bit, but the modern CPU inside your computer is 64-bit. So the x86 simply means \"these programs should be compatible with 386/486/Pentium/etc class 32-bit processors\", where as the programs in \"Program Files\" (without the x86) are 64-bit programs and not compatible with those old CPUs.\n\nIf you have the choice, you should go for the 64-bit programs as they'll be better optimised for your system.\n\n",
"Think of a computer as a desk.\n\nA 32 bit system (x86 version) is like a smaller desk with normal writing paper. The more stuff you try to do at the same time, the more cramped the desk (homework books, food, a laptop, drawing stuff.. etc). Also, the more you try to write on that paper, the more of the paper you have to use since the lines are far apart.\n\na 64 bit system (x64) is like a bigger desk with college or engineer paper (much thinner lines so you can write more stuff on a single page). Basically, since the desk is bigger, you can do more stuff at the same time, and since the paper is college level, you can write more stuff on it. x64 systems can also have more RAM (which is the quick access information) - more RAM is like like having a bigger desk. Even though BOTH (x86 / 32-bit, and x64 / 64 - bit) can have the same sized hard drives (imagine all your information in book shelves and closets behind you or in filing cabinets), the bigger the desk, the more quick access stuff you can grab without having to get up and use the shelves and filing cabinets over and over again.\n\nAs for the Folders, some programs are written very specifically to only be able to go up to a max of 32-bits. 64-bit software can still use them, but they are put into a different folder so that the operating system (and you as the user) can easily tell that something is still 32 bit vs 64 bit. Eventually that piece of software might get upgraded to 64 bit version, and instead of writing over the old program and potentially breaking it, windows will just install it to the \"program files\" folder, and leave the old \"program files (x86)\" version there for you to get rid of.\n\nFor some more specific details about the difference between x64 and x86, a bunch of others have posted good information. Google some speed differences between software using both x86 vs x64 for something interesting numbers as well. I am trying to keep this ELI5.",
"I have a related question.\n\nIs there any reason for differentiating the folders? I find it annoying that there were two potential places my programs could be stored in.\n\nI'm sure there would be reasons to install both versions of programs, maybe with interoperability reasons, but can't that be done by the program, not the OS?\n\nEdit: like Office. On my computer, I have: \n/Program Files/Microsoft Office \n/Program Files/Microsoft Office 15 \n/Program Files (x86)/Office 15\n\nAll from an x64 install of Office 2013\n\nI mean seriously, it's not like I ever need to go digging in those folders, but that's just weird and confusing.",
"Two folders were necessary to ensure older programs - that used a x86 architecture - would function in a 64 bit system. Programs sometimes need to reference other programs, and Windows keep them apart to \"hide\" the 64 bit programs from the old ones - they world break if they try to reference a 64 bit library. \n\nSame happens in the registry, but it is a lot less visible :) \n\n\n",
"(Long, but trying to explain each piece as simply as I can, so stay with me)\n\nThere are chips in a computer called a processor, or \"Central Processing Unit\" (CPU). This is where most of the calculations happen to allow a computer to function.\n\nThere are families of CPUs related to each other, that all \"speak\" the same language. And then there are other CPUs that speak a different language. For a program to work on a computer, it has to go through a process called compiling, which turns our a-z letters (programming code) into what is called an executable. The executable is in the language of the CPU it can talk to to run.\n\nx86 is the generic name for a family of processors made by Intel, and AMD for running 32 bit programs. 32 bit simply means how many bits exist to store information in memory, similar to a street address. 32 bits has a limit that modern computers need to bypass.\n\nLong ago, Intel saw a path to go beyond the limits of x86, including a new more efficient language. While x86 is widespread, ti does have some problems with being an older language. Intel called the new language EPIC, and built 64 bit processors (lots more addresses) called Itanium, or IA64 for short. Because they spoke a new language, they also had to include a little x86 chip too for working with old programs. The little x86 chip though wasn't very powerful, and older programs ran slowly.\n\nMicrosoft, the company that makes Windows, knew they had to make a version of Windows for Itanium, as Intel said it was the future. To allow people to run older x86 programs too, they basically combine two Windows into one. One that speaks x86, and one that speaks IA64. The IA64 was mostly in charge, but still needed the old x86 support files to let older programs run. Program Files had to be split to separate each kind of program.\n\nUnder the hood, Windows kinda presented a different view of the hard drive (where all your files, including the programs/executables) live. If an IA64 program ran, it saw it's Program Files in C:\\Program Files\\ as expected. If an x86 program ran, it also saw it's Program Files under C:\\Program Files\\. In reality, there are two folders, C:\\Program Files\\ and C:\\Program Files (x86)\\. Windows kinda lies to the x86 programs, to make sure they don't break if they had expected things to remain in the C:\\Program Files\\ area. This also happens in C:\\Windows\\System32, where all the system files lives, and on IA64 systems, oddly where IA64 system files went. C:\\Windows\\syswow64 contained the older x86 files, and would appear as C:\\Windows\\System32 for x86 programs.\n\nAs Intel rolled out Itanium chips around 2000, noone except high end businesses could justify paying for them. Intel figured in time the cost would come down, and they would also be the 64 bit migration path for home users. AMD however didn't like this plan, and instead began working to add 64 bits to the old x86 language. They called it AMD64, and several computer companies joined in supporting them. These chips ran x86 programs just as fast as old pure x86 processors could, unlike Itanium which ran x86 much slower.\n\nMicrosoft saw the PC companies using the AMD64 chip and realized once again they needed to make a Windows edition support it. They rushed out Windows XP x64 edition (a reference to AMD64 being renamed to x86_64), and kept all the same tricks and separation they used in the Itanium Windows version. Going forward because they set the standard already, they haven't ever remerged the folders and gotten rid of the secret swap out tricks that happen when an x86 or x64 program runs.\n\nApple, who makes another operating system called Mac OS X (roman numeral ten, not X) took a different path. Instead of separating files into separate buckets like Program Files and Program Files (x86), they used a technology called \"fat binaries\". This is where the different programs are glued together in one file, and the OS knows how to find the right part of the file. Fat binaries (or as Apple calls them Universal Binaries) are a little larger, but it minimizes the headaches from having to keep a copt of every language separated. This benefitted Apple, as they once supported processors that spoke a language called PowerPC, before switching to the same x86 and later x64 processors the rest of the home computer industry uses.",
"I saved this a while a go, it might help a little. \n\n[Link](_URL_0_).",
"Can anyone make a good argument for writing a 32 program instead if a 64 bit one?",
"Related boring fact: iTunes 64-bit tries to install itself in Program Files (x86). Noobs.",
"In this case, \"x86\" means 32-bit. Which is admittedly confusing, but the number 86 comes from the processor chip model numbers, not the number of bits.\n\nThe first chip in the line that became modern PC CPUs was called the 4004, and it processed 4 bits at a time. Then came the 8008, which processed 8 bits at a time. When Intel made a 16-bit version, instead of calling it the 160016, they named it the 8086, and a legacy was born.\n\nThe first IBM PC actually used an 8088, which was a small improvement on the 8086, but, crucially, it used the 8086 instruction set. PC software was written to use that instruction set, so all future PC chips were compatible with it. To indicate this, they all had names ending in -86: 80186, 80286, 80386. The instruction set/architecture used by the whole family is therefore called the \"x86 architecture\".\n\nThe 80386 - soon shortened to just \"386\" - was a big step because in addition to supporting the 16-bit 8086 instruction set, it added new instructions that let it work on memory 32 bits at a time. This greatly simplified memory management and allowed PCs to run what had previously been \"mainframe-class\" operating systems, like UNIX. It took a while (the 386 was released in 1985), but the 386 was the asteroid that took out the 16-bit dinosaurs of past PC hardware. \n\nBy the time Windows 95 came out, PC's were 32-bit machines. And they stayed that way for a long time. In April 2003, AMD released the Opteron chip, with 64-bit instructions, and we started down the path of 64-bit PC's. It again took a while, but these days just about every PC sold is 64-bit. \n\nBut there are still lots of 32-bit PCs, and 32-bit programs. 64-bit systems can run 32-bit programs, but the reverse isn't true, so it's helpful to keep the 32-bit and 64-bit programs separate. Especially if you might need both versions of the same program around. So the 32-bit versions go in \"Program Files (x86)\""
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://www.reddit.com/r/explainlikeimfive/comments/13vdn6/eli5_what_exactly_is_so_great_about_64_bit/"
],
[],
[],
[]
] |
|
5d30e1
|
why there are not much political movement to unify different countries that has very, very similar languages?
|
I watched some YouTube videos saying that some European countries has very similar languages (like the North Germanic languages) to the point that it's almost the same language.
As a Chinese, I find it strange that you people rather have different countries rather than one. The Chinese language has very large dialect difference, to the point different dialect equate to being a different ethnic/race in Chinese. "Dialect ethnics" still exist, we see that the different dialect ethnics have some cultural differences between each another, but we chose to identify as Chinese due to shared history, culture and language.
Is it not the same for these European countries that share the same language?
With so much talk about "exiting" nowadays (like Scotland), why hasn't unification got more popular/support?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5d30e1/eli5_why_there_are_not_much_political_movement_to/
|
{
"a_id": [
"da1cjtd",
"da1epng"
],
"score": [
4,
2
],
"text": [
"Just because two different countries have a very similar language, doesn't mean they also have very similar cultural and political beliefs, nor a shared history. When people still see themselves as a distinct group different from those in another country, there is going to be little push to unite into one country.\n\nThere is still a political movement toward unity. That's what the European Union is about, it just doesn't currently extend to the point of actually melting into one country.",
"In the case of my country and our northern neighbours, the problem IS shared history. We were once a part of them, we didn't like it and broke off in a revolt. That's still \"fresh\" enough that only a very small number of people think re-uniting the Netherlands would ever be a good idea.\n\n"
]
}
|
[] |
[] |
[
[],
[]
] |
|
9e6t7b
|
Did Napoleonic armies bring marching bands with them into battle like the film Waterloo portrays?
|
Title says it all really. Waterloo is my favourite film and I have this question every time I watch it. I've tried google multiple times, but haven't come up with any answers. Thanks for reading! :)
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/9e6t7b/did_napoleonic_armies_bring_marching_bands_with/
|
{
"a_id": [
"e5mkrfz"
],
"score": [
5
],
"text": [
"The fife and drums commonly played either together, where they would form a fife and drum corps - and Waterloo portrays that pretty accurately - bringing some musical umph, as well as pacing and rhythmn, to large line infantry formations on the field. \n\nThey could obviously also play separately if required - sometimes all you needed were the drums to beat the march, for example.\n\nCavalry and light infantry (the Rifles for example) both bought buglers (or cornets) with them, more for direction/instruction than music though. \n\nThe Rifles officers also used whistles, but that's definitely not for anything other than transmitting orders.\n\nOne thing in Waterloo is the scene with the Highland regiments going forward, in this we see what could be compared to modern day Highland pipe & drum bands arrayed before their battalions - this is one of the few things the film gets wrong, as such accompanying bodies didn't exist until later in the British army.\n\nSo, in summary, they didn't bring 'marching bands' - which sounds very modern and American to me - but they were accompanied by their respective musical personnel, as Waterloo rightly shows, for the threefold purpose of morale, music and direction/instruction, such as keeping step, the tempo and thus pace of the marches and so on.\n\nI hope that answers your query?"
]
}
|
[] |
[] |
[
[]
] |
|
96h8ye
|
why do our butts hurt after sitting for a long period of time?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/96h8ye/eli5_why_do_our_butts_hurt_after_sitting_for_a/
|
{
"a_id": [
"e40eh3g"
],
"score": [
10
],
"text": [
"Well, the pressure causes your muscles to press against your bones, which hurts for example, pinch you arm. Your flesh is getting crushed, so it hurts...."
]
}
|
[] |
[] |
[
[]
] |
||
2rydd7
|
Does Monty Hall Problem solution apply to Italian gameshow?
|
Mathematicians of the internet, here's a question that's been bugging me for a while...
So there is this famous gameshow in Italy:
You get assigned one of 20 numbered boxes, that contain different money prizes ranging from 0,10€ to 500.000€.
You don't know what's inside yours or any other box.
During the whole show you basically call randomly the numbers of the other boxes you want the host to open and the prize they have inside is lost; slowly lowering the number of boxes, therefore prizes, left in the game.
At the end of the game you are left with 3 (or 2, it depends... But let's say it's 3) boxes, maybe 2 containing a low prize and one containing a high one.
You are then asked if you want to swap your box with any other and then open the 2 left, one by one.
My question is: has the famous Monty Hall problem anything to do with this gameshow? Should you always swap trying to get the best prize? Thanks in advance!
EDIT:
spelling
|
askscience
|
http://www.reddit.com/r/askscience/comments/2rydd7/does_monty_hall_problem_solution_apply_to_italian/
|
{
"a_id": [
"cnkmahe",
"cnknkei",
"cnknrg0"
],
"score": [
20,
2,
3
],
"text": [
"The key ingredient that makes switching best in Monty Hall is that the host removes a losing option. The host adds his own knowledge of which door is bad into the mix. Since this does not happen in this case, all the remaining boxes have the same odds of being the best box. So there will not be any benefit to switching.",
"The only way that it could apply is if the producers have some knowledge of the contents of the contestants case and if that knowledge is in some way transmitted to the contestant, either through the bank offers that are being made or the level of encouragement from the host to switch.\n\nIf there's no knowledge or transmission then the Monty Hall problem doesn't apply.",
"In this game, the Monty Hall analysis does not apply and it does not matter whether you switch boxes at the end or not. You can not increase (or decrease) your expected winnings by switching. Your expected winning at the start is equal to the average of the 20 prizes; your expected winning at the end (when only 3 boxes remain) is the average of the three remaining prizes.\n\nThe game is equivalent to the following: first you randomly pick out one box B1 of the 20, then you pick two more: B2 and B3. You now know the prizes in the three boxes, let's say one high prize and two low ones, but you don't know which is which. Given that knowledge, should you switch from your box B1 to B2 or B3? The answer is: it doesn't matter, your chance of getting the high prize is 1/3 no matter what. \n\nThe reason is that by initially picking B1, then B2 and B3, it's equally likely that B1 or B2 or B3 contains the biggest prize of the three, so the probability that either box has the highest prize is 1/3.\n\nNow, the analysis for a person who decides to stick with B1 goes like this: the chance that B1 contains the high prize is 1/3; they didn't switch, so they'll win the high prize with probability 1/3.\n\nThe analysis for a person who decides to switch goes like this: if B1 contained the high prize (chance 1/3) and you switch, you'll end up with the low prize. If B1 contained the low prize (chance 2/3) and you switch, you'll get the high prize with probability 1/2. Altogether, you'll get the high prize with probability 1/3 * 0 + 2/3 * 1/2 = 1/3, just like the other person.\n\nThis problem is different than the Monty Hall problem: by randomly opening boxes yourself, you don't gain information about the location of the higher prizes in the remaining boxes. By contrast, Monty Hall, who is forced to open doors with low prizes only, thereby gives out some information about the location of the high prize.\n\nEDIT: My analysis above assumed that you were allowed to pick the initial box randomly. I just reread the question, and it says that you get \"assigned\" the initial box. That opens the possibility that the producers of the show, who presumably know the location of the high prizes, deliberately assigned a low-prize box to you. Then you need to analyze the problem with game theory. If you want to maximize the worst-case outcome in the face of a hostile opponent, which is what ordinary game theory always does, then you should switch at the end. The reason is that the hostile producers could control the contents of your box, but not the contents of the other two remaining boxes."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
6moo8w
|
how nuclear weapons could have been dropped and tested in nevada, without the nuclear fallout or radiation harming civilian populations in the surrounding communities.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6moo8w/eli5_how_nuclear_weapons_could_have_been_dropped/
|
{
"a_id": [
"dk35bfj"
],
"score": [
3
],
"text": [
"they tested them in super remote areas, and before long, they stopped testing them above ground or under water (or space), they would detonate them underground, so the radiation would be contained.\n\nthere is a low level of radiation across the globe that didnt exist before nuclear testing. generally inconsequential for humans, but still measurable."
]
}
|
[] |
[] |
[
[]
] |
||
2a2e98
|
What is the volume of an "average" event horizon?
|
We often see these artistic renderings of a black hole floating in space with the light from distant stars warping around it. The problem is the lack of bananas in space for scale.
I think the common image people have is the event horizon being nearly as big as the star it started as. But if I imagine a star slowly shrinking, the dencity slowly increasing, there will be a point where the light can't escape creating the event horizon; the volume at this point surely is a fraction if the original volume.
TLDR: would the volume of an event horizon of an average black hole be closer to a planet or a beach ball?
|
askscience
|
http://www.reddit.com/r/askscience/comments/2a2e98/what_is_the_volume_of_an_average_event_horizon/
|
{
"a_id": [
"ciqw24q"
],
"score": [
5
],
"text": [
"There's an equation for that. Actually there are a few equations for that. For a non-charged, non-rotating singularity (a Schwarzschild black hole) it is: r = 2GM/c^2 where r is the radius of the event horizon, G is the gravitational constant, M is the mass of the singularity and c is the speed of light in a vacuum and V = 4/3*pi*r^3. Keep in mind, a Schwarzschild black hole is the \"ideal;\" most black holes formed in nature would be rotating at least, so would use the Kerr (rotating) or Kerr-Newman (electrically charged AND rotating) metrics and volume equations for ellipses."
]
}
|
[] |
[] |
[
[]
] |
|
boqinp
|
what happens when there isn't enough electricity on the grid?
|
I.e. if 1000 households need power, but one of the powerplants has broken down and there is only enough power generation to power 900 homes.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/boqinp/eli5_what_happens_when_there_isnt_enough/
|
{
"a_id": [
"enjc1k0",
"enjepl0",
"enkqtvo",
"enl4cbm"
],
"score": [
2,
4,
2,
2
],
"text": [
"In short: a brownout is what occurs then. There will still be power to the majority, but not everyone.",
"There can be \"brown-outs\" where the voltage is lower than normal. Lights will dim and some appliances won't work or could even be damaged.\n\n & #x200B;\n\nRolling black-outs are another possibility, where the utility actually shuts down portions of the grid to allow the power they do have to serve a smaller area. They often turn on and off different areas so everyone is equally pissed off (seems fair).",
"The first thing that happens is that the generators on the power plants that are operational will have trouble upholding the expected frequency. Too much load, and the frequency goes down. Not enough load, and the frequency goes up.\n\nThey can, to some extent, alter the flow of the steam or water that makes the generator turn so that it gets better at meeting the expected frequency. In fact, they do this all the time to keep the frequency as accurate as possible.\n\nBut...if you have a buffer where a generator can meet an abrupt requirement to dial up the frequency by 10%, then you are also constantly underproducing by 10%. Which is a financially dumb thing, because you are making 10% less money than you could make just to have a buffer.\n\nIn other words, its unlikely that the remaining producing power plants can immediately meet a 10% production loss by just dealing up their own production.\n\nTo some extent, of course, they totally can. Which means that, in reality, i'ts not 100 houses without power any more. It's more likely that it's 70 or thereabout.\n\nUnfortunately, that is the extent of what they can achieve on their end. After that, it's time for some rough choices.\n\nSomeone in the power grid system is responsible for something called *balancing*. Which is a fancy word that means \"input and output must be balanced. We have to produce as much as we consume. And we have to make sure that we are not consuming more than we produce.\"\n\nIn that lies the solution, so to speak. If production fails, consumption must go down.\n\nThis is done, literally, by giving a remote command to a huge circuit breaker. Effectively turning off power for a cluster of customers.\n\nThe Balancer always, always, always has a plan for this. They know already that \"if plant A falls out, I have to turn off city X.\"\n\nAnd, because it's a massive issue for everyone to get their power turned off like that, we all have to share the burden.\n\nCity X is turned off for a predetermined period of time. Say...15 minutes. After fifteen minutes, they proceed to the next part of the plan, which is to turn off City Y and Z who together are nearly as large consumers as city X. And then they get to run like that for 15 minutes.\n\nAnd so on.\n\nThat type of rotation will be kept up for as long they are unable to secure production at another power plant somewhere else that they happen to have power lines to.\n\nThis is why most countries have power lines that cross borders into neighbouring countries. Because if shit hits the fan severely, at least you can buy production from another country.\n\nYou have a 10% buffer you can use to meet...issues. They do too. And they are willing to sell that buffer to you, if you are just willing to pay. And...well. You are willing to pay, because the alternative is to keep up the rotating blackout until you have more producers lined up and running.",
"\"The grid\" in ELI5 terms is essentially like a spinning class where all wheels of the spinning bikes are connected. The powerplants are pedaling. The consumers apply the breaks on the wheels. The harder a consumer applies the break, the more energy he gets.\n\nThere is a \"deal\" between powerplants and consumers about how fast the wheel should spin. Depending on where you live, it's either 60 (most of the Americas) or 50 (rest of the world) rotations per second. This is called frequency.\n\nIf you've ever done spinning, you know what happens when the breaks are applied too hard - you slow down. So you have to pedal harder (tell powerplants to produce more energy). Or you have a deal with the spinning class in the next room, and if you're a bit short on spinners, you can hook up your bikes to theirs, so they help you keep your frequency (i.e. import power from a different grid / nation).\n\nThe amount of energy a consumer gets is dependant on the frequency and how hard he applies the breaks.\n\nConsumers have in ELI5 terms two different kinds of devices hooked to the grid. One kind is \"directly attached\", for instance motors and classic light blubs. If the frequency goes down, the motor just runs slower and the light blub is less bright, but they keep pushing the breaks equally hard.\n\nThe other kind are \"switching power supplies\". They become more and more wide-spread, for instance in your computer, in your LED bulb, to charge your phone, your internet modem, your TV, and so on. They draw power from the grid to transform that power to a different \"format\". They need a specific amount of power and don't care too much about the frequency. If the frequency goes down, they just apply the breaks harder to get the amount of power they need. This can become a chain reaction if the grid operator doesn't act quickly.\n\n & #x200B;\n\nedit: so, with all this pretext, what happens if there's not enough power? If nobody takes action, the grid just fails for everyone; a \"black-out\". But a grid operator will usually just kick some customers out and prevent them from applying the breaks. Those customers then sit in the dark. This is called a \"brown-out\"."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
5wogb1
|
how does a toilet flush without any power?
|
It sounds sort of silly but i saw a r/showerthoughts which mentioned that power-less toilets are very impressive and don't get any recognition so I figured I'd ask the experts to explain this wonderful phenomenon. Thanks!
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5wogb1/eli5how_does_a_toilet_flush_without_any_power/
|
{
"a_id": [
"debm9lj",
"debmfop",
"debmgmw",
"debmhfq"
],
"score": [
2,
2,
2,
4
],
"text": [
"It works on the concept of a \"siphon\". Water wants to travel downwards due to gravity, but there is an obstacle such as an upward slope or \"wall\" it needs to overcome. Once some of the water overtops that obstacle, it will travel downwards due to the force of gravity.\n\nNow, the interesting part is: If you design a system right the water that has overtopped the obstacle will *pull the other water over the obstacle and along with it* because there is no way for air (or whatever) to fill the gap that's left behind. The water already has some potential energy to flow downwards, by virtue of being above the sewer. The siphon lets it overcome the obstacle and flow downwards like it naturally wants to.\n\nAn interesting point is that energy WAS added to the system when water was lifted up to the toilet, above the level of the sewer. The siphon trick just lets it stay in one place until you add some more water, which lets it all run downwards. ",
"The U bend at the bottom is level with water on both sides with a gap of air at the top, once you go poop poop and flush, water goes in and replaces all the air within the top of the U Bend and sucks all poop poop down. Air comes back in with the water until eventually both sides of the U Bend are equal again and no poop poop remains, and bowl fills back up with watah ",
"The flush toilet works thanks to the concept of the [Pythagorian Cup](_URL_0_)\n\nThe pipes in the toilet have a section that brings it above the water line in the bowl. And a tank is connected to the bowl that fills with water.\n\nWhen you push the flush lever, the tank drains into the bowl, raising the water level over the pipes. When that happens, the water in the pipe starts to flow over and out of the toilet, sucking the rest of the water in the bowl with it.\n\nThe water from the tank continues to refill the bowl with cleaner water until the tank is empty, with the pipes eventually not getting enough water in them to continue flushing.\n\nThe remaining water stays in the bowl.",
"A plumber will correct me, but there are three types that I know of, none of which use electrical power Directly, but all of which rely upon some kind of power source upstream of the toilet to generate some potential energy that \"powers\" the flush kinetically. \n\n- Typical residential tank toilet uses a gravity drain of the water in the tank to flush your stuff. It takes power in the form of a well pump or city water supply pump to lift the water into that tank in the first place.\n\n- Another variant of tank seen less commonly is one with a bladder. In these, the water pressure fills an enclosed bladder (not an open tank) which creates a more pressure for a more sudden and forceful flush.\n\n- The typical commercial toilet seen in public restrooms has no water and but relies instead on the higher water pressures of a commercial building to flush the bowl. \n\nNone use electricity at the toilet itself. But all release some potential energy that originates with an electrical pump upstream somewhere. So in the sense of physics, they are all \"powered\" but not in the common sense of the word.\n\nI'm sure someone is going to provide a fringe example of a system that is not electrically pumped, and that is possible but uncommon."
]
}
|
[] |
[] |
[
[],
[],
[
"https://en.m.wikipedia.org/wiki/Pythagorean_cup"
],
[]
] |
|
51cd72
|
"Doing" indigenous history
|
I know those who argue that indigenous histories (and would apply this applies also to non-western histories to some degree) cannot be done using western historical methods and thought. That one cannot understand such histories without using the methods of those cultures. I am curious about the thoughts of historians on this.
Doesn't such a leap lead to an ultimate rejection of any ability to know or represent the past at all?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/51cd72/doing_indigenous_history/
|
{
"a_id": [
"d7ayb0w",
"d7b1lih"
],
"score": [
3,
2
],
"text": [
"In my area I often hear people speak of indigenous pasts; or representations of the past, as 'history' as a study - or as a science- is a profoundly and specifically western approach to the study of the past, albeit one that has greatly influenced the approach of people across the globe to the study of the past.\n\nI would say, its not a rejection of our ability to know or represent the past, but an acceptance that there are many different ways to represent the past, that history is always just a re-presentation of the past influenced very much by the time and place, or context, of its recall. Hence, historiographies shift and the lens or focus we deploy to read the past is influenced greatly by the vantage point of our present.\n\nThere have been tons of great writers that have tackled this from various POV in the Pacific- it is an ongoing conversation as I believe you allude. First to mind is the estimable Greg Dening, but also John Waiko or Minoru Hokari and more recently Teresia Teaiwa and Chris Ballard have all had interesting things to say on the topic.",
"This question points to something interesting that I am starting to look into in a more academic way, so I am sorry if my response sounds a bit crude. In archaeology, there is a growing, yet no mainstream or hear about, movement that is referred to as “Indigenous archaeology”. This is not archaeology done by indigenous or about indigenous, bur rather a process of doing archaeology that very actively takes into account collaboration with indigenous stakeholders, indigenous epistemologies, and native conceptions of the past, history, and time, and very importantly questions the role of research in a given community.\n\nMainstream archaeology has utilized western epistemologies (aka the scientific process) to study and understand the practices and lifeways of non-westerns, many of whom held very different worldviews and ideas about knowledge acquisition that operate on a different set of ontological and epistemological principles. For example, a lot of archaeologists reject the use of oral traditions as valid repositories of knowledge because of the lack of validation. This research very often is carried out for the benefit of western scholars, is produce and reproduces using western methods of recording history (external from people, held in books and articles for purchase), and is taught in western institutions of higher learning or sold to western public audiences. People like Vine Deloria among others, would argue that this way of doing archaeology (or anthropology for that matter) is a child of colonialism and a further exploitation of Native people. Even at times when archaeologists do public outreach, it often entails a unidirectional design of “us” archaeologists giving “them” (the other, either western or non-western) answers to questions chosen by the researchers, that benefits the researchers careers. \n\nThus indigenous archaeology makes a call and provide a variety of possible pathways to start decolonize the modern practice of archaeology. For example, indigenous archaeology calls for research that is done for the community (no just for the researcher), in a collaborative way (not a consultative way) that includes stakeholders in the research design, carrying out the research in appropriate ethical ways, final interpretations, as well as the dissemination of knowledge through culturally sensitive pedagogical ways. Of upmost importance in this approach is the acceptance that (true to its post-modern roots) western ways of thinking and knowing the past are not superior to non-western ways. This is not to suggest a nihilist view of knowledge where everything goes, but the acceptance that the scientific process (just as any cultural practice for that matter) is produced, reproduced, affected, and affects daily practices. As such, human ways of knowing and understanding our world can be disrupted, changed, and improved upon. Historical knowledge is not a constant static thing, but a reflexive entity that talks back at us as we talk to it. In that way, Indigenous archaeology is a manifestation of multi-culturalism that attempts to reclaim traditional epistemologies and ontologies for knowing the world. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
98b7jf
|
The freezing point of carbon dioxide is -78.5C, while the coldest recorded air temperature on Earth has been as low as -92C, does this mean that it can/would snow carbon dioxide at these temperatures?
|
For context, the lowest temperature ever recorded on earth was apparently -133.6F (-92C) by satellite in Antarctica. The lowest confirmed air temperature on the ground was -129F (-89C). [Wiki link to sources](_URL_0_).
So it seems that it's already possible for air temperatures to fall below the freezing point of carbon dioxide, so in these cases, would atmospheric CO2 have been freezing and snowing down at these times?
Thanks for any input!
|
askscience
|
https://www.reddit.com/r/askscience/comments/98b7jf/the_freezing_point_of_carbon_dioxide_is_785c/
|
{
"a_id": [
"e4eonte",
"e4eoptr",
"e4eoswl",
"e4ep2jc",
"e4epurx",
"e4eq69f",
"e4erlf2",
"e4ermba",
"e4ew58b",
"e4ewqkf",
"e4f4ao7",
"e4f5qia",
"e4fem2r",
"e4fnhts"
],
"score": [
4,
536,
6596,
138,
38,
402,
28,
4,
22,
26,
6,
14,
7,
34
],
"text": [
"[No, there’s too little of it in the atmosphere for it to condense out.](_URL_0_) ",
"It's cold enough, but there is very little CO2 in the atmosphere. You can't look at the sublimination point at 1 atm because the partial pressure of CO2 is much lower. The low partial pressure of carbon dioxide would cause it to subliminate in this environment--some molecules are freezing out, but at the same time others are sublimating and there is no accumulation.",
"Yes and No.\n\nHypothetically yes, a container of CO2 would freeze in those conditions, in a practical sense though, CO2 only makes up 0.04% of the atmosphere, and, unlike water nucleating into raindrops, won't gather into single places, so you wouldn't actually get dry ice snow. ",
"Not really. This has nothing to do with freezing point and everything to do with saturation: air can contain humidity even if the air temperature is below freezing. At some temperature carbon dioxide *will* precipitate out of the site as dry ice \"snow\", but that temperature is very low because there is very little CO2 in the air, about 0.04%. \n\nCompare that to water, which typically make up about 1% of the air and has a much higher freezing point.",
"You can see from here\n\n_URL_0_\n\nThe vapor pressure of CO2 at -92 C is about 200-300 mmHg. For comparison normal atmospheric pressure is 760 mmHg. So for CO2 to start depositing at that temp, the atmosphere would need to be over 1/3 CO2.",
"Interestingly, even at -90C, a pile of dry ice will still sublime away, since the partial pressure of CO2 in the atmosphere is so low.",
"It could snow dry ice, sure, just as it can snow water ice at 0 degrees C. It doesn't though, because you have to have saturation of CO2 in the air to force the condensation/precipitation, and generally speaking, CO2 concentrations are well below saturation. This is essentially the same reason it does not always snow when the air temp falls below 0C.",
"I will say there are other factors to consider. First off a mix of gasses like the atmosphere will have different properties then the individual gases that it is made of. Not sure in this case if it affects the CO2 but sometimes mixtures will have higher or lowing freezing points. Also that freezing point temperature would be dependent on things like how far it is from sea level and pressure. Water boils at like 70C on mount everest (can't have coffee up there).",
"1. The amount of CO2 in the atmosphere on Earth is not in a high enough concentration to cause CO2 snowfall. \n2. At the locations in Antarctica that experience these temperatures the air is extremely dry and there would be little H2O to cause normal snowfall. Some, but these temperatures occur in a desert.",
"Vostok's altitude is 3488 m (11,444 ft), it's lowest temperature was -89.2 Celsius in 1983. The pressure at that altitude is 658.5 mb (0.65 Atm. pressure). It appears from [this diagram](_URL_0_) that CO2 would be become solid somewhere between -85 and -90 Celsius at 0.65 Atm, so it is borderline.\n\nCan anyone confirm if CO2 is solid at these conditions?",
"No. The vapour pressure of CO2 in the atmosphere is too low, so dry ice in the South pole, in the winter, would sublime faster than it would accumulate replacement CO2 molecules from the air. Similarly, CO2 molecules in the air are too far from each other (ie the vapour pressure is too low) on average to make dry ice dew likely.",
"No.\n\nAlcohol boils at 78 celcius.\n\nWater boils at 100 celcius.\n\nA mixture of water and alcohol boils at a temperature between 78 and 100 celcius, depending on how much water and alcohol it contains.\n\nSame with oxygen, nitrogen and carbon dioxide in the air. As air contains mostly nitrogen, it's freezing point is going to be closest to that of nitrogen, and when it freezes, you will get nitrogen, oxygen, argon and CO2 snow all mixed together",
"So the answer is no because the earth has an atmosphere of oxygen and nitrogen both lighter than carbon dioxide preventing it from floating upwards to cool down enough for carbon dioxide snow. Not to mention that I don't believe rain can form at the current concentration of 0.04% of the atmosphere.\n\nYou would have layers of frozen carbon dioxide though because both nitrogen and oxygen have lower freezing points meaning the carbon dioxide would condense on your car's window. Lucky you're already dead at that point so you won't be inconvenienced by it.",
"Physicist here. Many inaccurate and uninformed answers in this thread. \nFirst some facts and observations: \n- CO2 will behave *exactly* like H2O. (It is not enough pressure for CO2 to be liquid, but that is not relevant at low temperatures) \n- Content of CO2 in atmosphere is pretty constant, while H2O varies a lot. \n- Materials have a vapor pressure at a given temperature. \n\nThe vapor pressure for CO2 at -78.2°C is 1 Atm., Above that, no CO2 snow can form.\n\nIf it is colder, CO2 snow will form if the partial CO2 pressure is above the vapor pressure at that temperature. (equivalent to **dew point** of H2O) \n\nAt -100°C, the vapor pressure of CO2 is 0.13 Atm. Since it only is 0.04% CO2 in the atmosphere, its partial pressure is 0.0004 Atm. So it is far above CO2's dew point.\n\nAt about -147°C, CO2 vapor pressure is the same as its partial pressure, and CO2 would condense out of the atmosphere as snow. It would also form frost on objects. \n\nIn the unlikely event this happened, CO2 would evaporate (like dew in the sun) when the sun warmed it up, and at that short time you could have local pockets of higher concentration of CO2. You could then see CO2 frost condensing as snow or frost up to -78.2°C if this was quickly cooled down again.\n\nTL;DR CO2 will first form snow and frost at -147°C or colder in normal air."
]
}
|
[] |
[
"https://en.wikipedia.org/wiki/Lowest_temperature_recorded_on_Earth"
] |
[
[
"http://hernadi-key.blogspot.com/2009/06/lab-experiment-regarding-co2-snow-in.html?m=1"
],
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Carbon_dioxide_(data_page)#Vapor_pressure_of_solid_and_liquid"
],
[],
[],
[],
[],
[
"https://hub.globalccsinstitute.com/sites/default/files/imagecache/620xH/publications/19011/advanced/fig-024.jpg"
],
[],
[],
[],
[]
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.