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<\|im_start\|>user ELI5: How does Turing machine capture the essence of computing?<\|im_end\|> <\|im_start\|>assistant Let's say someone wants to make a peanut butter sandwich, but has never done it before. Could you give this person a list of steps to follow that always makes a peanut butter sandwich? Yes! It would start with something like "get two slices of bread" and go on to "open a jar of peanut butter", and eventually end with putting the whole sandwich together. Anyone who could understand your list of steps could make a peanut butter sandwich. Now let's say someone wants to write a song that everyone they know will love. Could you give this person a list of steps to follow that always makes such a song? You could try to tell this person what kind of songs you love, or teach them things about music and lyrics, but no matter what you tell this person, they might not be able to write a song that everyone they know will love. Why are there some things that you can always make if you follow the right steps, and other things that don't seem to have steps that always work? It is important for people who study math, logic, and computers to know what things you can always do with a list of the right steps and which things don't have steps that always work. After all, a computer can only do something if you can tell it how with a list of the right steps! (In fact, the original "computers" were actually people who knew the right steps to figure out the answers to hard math problems using pencil and paper!) People who study computing call a list of steps that a machine (or a well-trained person!) can follow an "algorithm". In order to understand what things you can or can't do with an algorithm, you need to say what an algorithm is in the language of math. There was a time when people weren't sure how to do this, but a man named Alan Turing figured out a way. A "Turing machine" is what we call Alan Turing's way of saying what an algorithm is in the language of math. Around the same time that Alan Turing came up with his way of saying what an algorithm is, a man named Alonzo Church came up with a different way of saying what an algorithm is in the language of math. We call Alonzo Church's way the "lambda calculus", and it turns out it says the same thing as Alan Turing's way, just phrased a little differently! Turing machines "capture the essence of computing" because they give us a way to carefully describe what it means to be an algorithm. Anything that is an algorithm you can phrase as a Turing machine, and anything you can make a Turing machine do is an algorithm. With this careful way to say what is or is not an algorithm, mathematicians and computer scientists can study what it is possible or not possible for a computer to do!<\|im_end\|>
<\|im_start\|>user More perspectives wanted: Choosing postdocs and balancing a dual-career/two body problem Background: I am a new STEM Ph.D. who is in a relationship with another new STEM Ph.D., Partner (they/them/their pronouns). I defended this semester; Partner defended last. I am a mildly successful scientific researcher more known for my STEM education and diversity initiatives. My partner is an extremely successful early career researcher in their field who has successfully landed a great 2yr industry postdoc that fulfills all of their short term goals (professional development, supportive environment, indication of being able to stay on post-contract, a regular work schedule, etc.). I have a definite wish for a faculty-academic position whereas partner values stability and tentatively likes the industry environment so far (all of 1 week in), though definitely enjoys teaching. We're currently working on the assumption that after 2-4 years here (depending on how jobs work out) my career will take precedence, moving where needed for me to secure a faculty position as long as it's anywhere my partner could find a position in their rather flexible industry. Partner's job is in a geographical location where me finding a position is not difficult, but it may not necessarily be the absolute ideal. I am currently evaluating 3 types of positions and would appreciate it if any STEM faculty members could provide insight into what might make one type of position better on a CV (and for what type of institution) over another. Or if any of the positions would be definitely detrimental even if I followed-up with a second postdoc. And for those who have navigated the two-body problem, what your opinions are at all. Position A: A postdoc at the local R1 working for a PI in a field that is doing work I find mildly interesting, but would not necessarily fit my current research agenda. Opportunities posted now but also possibly open in the future as well. Distance from Partner: none Position B: A 1-year postdoc in an R1's Center for Teaching focused on STEM education and Teaching, which provides opportunities to be instructor of record on classes (not a current skillset) and do formal education research, which I attempted independently as a graduate student. Distance from Partner: 1hr commute, but able to live at "home." Position C: Absolute research "dream" postdoc directly in my field at an amazing institution. Fellowship is also limited to 1 year. Distance from Partner: 9hrs. Similar research-intensive positions are possible but also between 2.5-9hrs away and vary in reputation. Note: I'm my entire committee's, and advisor's, first Ph.D. graduate. In hindsight I would have chosen at least one person with experience to help me navigate this process but at the same time I would never replace their support and mentoring. Therefore I turn to you. You might hear from me frequently in the next month or two. TL;DR: I am in a two-body relationship where my partner has secured an excellent position. I'm trying to figure out if any of the positions I am looking at will have unforeseen (or larger than foreseen) consequences on my hopeful career as a faculty member or my highly valued relationship.<\|im_end\|> <\|im_start\|>assistant The problem with picking 1 or 2 is that in 2- 4 years when it's your turn to choose, your CV will be weaker for it and your choices more limited. In theory, it sounds good to put your career on the back burner to support your partner and so you can live with them. In practice, your CV will be compared to your peers who did take the dream option 3 and have the cutting edge research, in line with their PhD research, publications and recommendations from well known professors to bolster their applications. And your partner will be up for promotion in his current position. Maybe you've bought a really nice house. And suddenly it's never really a good time for your career to take precedence. I say take option 3 because you already know that professionally, it is the best route to take.<\|im_end\|>
<\|im_start\|>user PhD student - Asked to write a letter in support of tenure; mixed feelings about professor I am an advanced PhD student in a STEM field at a prestigious R1 university. I was asked to write a letter in support of tenure for Professor S. I've been around enough labs to know what is normal and not-normal behavior. Professor S brings a lot of money into the university and has a large lab. I worked as a sort of consultant for a year for Professor S's lab because I have a specific skill set he needed. He paid me hourly and also provided some mentorship. He is not my direct adviser. I was considered part of his lab but not really one of his students. His tenure does not affect my career. Professor S was very helpful to me in many non-trivial ways. I think he genuinely tries really hard to be a good mentor. That being said, working with him was very challenging. Without getting into much detail, I started to really regret not having a contract with him because he kept adding unreasonable requests to my workload that we never agreed upon. He threatened my career when I tried to decline work for him (I was declining a task I had never agreed to do originally). He doesn't take "no" for an answer... He definitely uses emotional manipulation or tries to convince you that what he wants is in your best interest. For an example, he demanded a PhD student skip a big exam for a required class to add the finishing touches to a conference poster that wasn't even due for another week. He totally derailed this student's NSF proposal by making this (frankly trivial) poster the utmost priority. He wanted it done urgently and didn't think the student's class was important. His PhD students refer to him as a bully. They've all learned to be incredibly blunt and assertive with him. He treats students that work in his lab very disrespectfully when he is anxious or angry. He yells at undergrads, coordinators, and PhD students out of frustration. He will also apply unreasonable amounts of pressure to get certain tasks done without understanding the scope of what he is asking (because he's never worked extensively with this type of protocols or equipment himself). Often, due to his pressure to get things done in a truly unreasonable time-frame or without people being properly trained, things don't get done right and resources are wasted. His entire lab is held together with stopgap solutions that end up making more work for everyone in the long-run. I would not recommend that future PhD students join his lab. I've personally managed to set boundaries with him but it was a very difficult process and I had to get other faculty members and campus services involved to defend me (which they all did). I am still extricating myself gracefully. So, my question is, is this the sort of thing the tenure committee cares about? Is it appropriate for me to write a bad letter or perhaps just not write one at all? I could talk about the good stuff (there is some) but I would also feel obligated to mention the bad. I doubt it will matter since he brings in so much money but maybe it would be useful to have on file? My department pretends to care about students but when push comes to shove they don't. TL,DR: Professor I work with is awful. Do I write a bad letter, a weak letter, or no letter at all in support of his tenure? Edit: I am not sure how relevant it is, but I know that at least one of his PhD students is also declining to write a letter and has already spoken to the head of the tenure committee about it. Another edit: Technically I was invited by the committee to, "contribute a letter commenting on his candidacy" which is a bit different than being asked to write a letter of recommendation. FOLLOW UP QUESTION: Could it hurt me somehow if I decline to write a letter (and he knows I was asked?)? Are they kept confidential forever?<\|im_end\|> <\|im_start\|>assistant Tenure committees tend to listen to graduate students. They aren't super impactful, but they will listen. If you have serious concerns, I'd say you should write the letter, talk to your internal graduate student association, and have the society send the letter unsigned. Academia is not like a normal workplace, and things like this can come back and bite you.<\|im_end\|>
<\|im_start\|>user ELI5: Why do people with much different accents than mine seem more charming? For example, I'm an American, and all the videos I see of Australians and British people, they just seem so damn charismatic. Why?<\|im_end\|> <\|im_start\|>assistant Social status and media influence. Ever wonder how nobody thinks the Indian or Asian accent is sexy in english? Media told you Aussie accents are sexy and Indian accents are comedy accents. Look at Russian accents....women speaking? Sexy....man speaking? Gangster or not sexy.....at least in the USA. No surprise.....USA media is filled with violent Russian gangsters and sexy Russian women in need of a helpful american boy.<\|im_end\|>
<\|im_start\|>user ELI5: How do you drive a stick-shift?? keep in mind i'm only 5 years old<\|im_end\|> <\|im_start\|>assistant Your car has a gas pedal, a brake pedal, and a clutch pedal. The brake stops the car, the gas speeds up the car, and the clutch allows you to level up your gas pedal. Think of Mario Kart. Princess starts zippy and but her top speed isn't so good. Koopa starts slow but at top speed he is very fast. Mario is in the middle category. Switching gears from 1 through 5 is like switching from Princess to Mario to Koopa as you are driving. The way you switch gears is to hold down the clutch while you move the stick shift to the number you want. If you are at a dead stop, you want to be in 1 so that you can take off fast (like Princess). Then, when you hit Princess' top speed you want to switch to 2, and then when you hit that top speed you switch to 3, then to 4, and then finally if you are getting on the highway then you want to use Koopa because he has the best top speed. (Adult explanation: step on the clutch whenever you move the stick shift, then step off of the clutch when you've made your selection. If you don't hold down the clutch while shifting then the gearbox makes a loudass grinding noise.)<\|im_end\|>
<\|im_start\|>user What does it take to become faculty at a place like MIT? Is it papers? Is it education? Adviser ? Demonstrated success ? Potential ? All-around-good scientist? Best-in-the field? All of the above? In short, what does it take to become selected as assistant professor (since associate and full professor probably changes the answer) at a place like MIT? MIT is a placeholder here, it could be any top institution.<\|im_end\|> <\|im_start\|>assistant High impact papers, ability to get grants, interesting cutting edge work, how this work fits in with what's currently being done in the department (you probably shouldn't be in direct competition with other faculty, particularly senior faculty), and how much the faculty and chair like you for whatever the reason.<\|im_end\|>
<\|im_start\|>user Any way to logically explain how Werewolves can undergo nearly spontaneous metamorphosis? Werewolves of the Underworld variety or similar. This always bothers me when dealing with Werewolves in fiction. The gain/loss in mass doesn't make sense. Rapid changing of bones, teeth and fur could maybe be possible at the cost of extreme pain if the "materials" were stored somewhere.<\|im_end\|> <\|im_start\|>assistant Obviously, the sun light, when reflected off the moons full surface, changes in wavelength to induce transformation in the werepeople. The muscles expand by rapid mitosis, also brought onto by a chemical reaction between the moon and the mutated gene in werepeople. The hair comes from the extra protien they store while in their dormant form.<\|im_end\|>
<\|im_start\|>user Are there tasks that can be done more efficiently by government than by private enterprise? There is an idea in contemporary culture that businesses are simply better at most tasks than government because they are motivated by profit and literally can't afford to lose money. Are there nay tasks, though, that can ONLY be performed by a government, or that can be more efficiently done by a government?<\|im_end\|> <\|im_start\|>assistant One typical example would be natural monopolies. It just doesn't make much sense if companies all had to build their own electricity network for example. Another typical example are public goods. Public goods are defined by being non-rivalous and non-excludable, and because of that often suffer from the free-rider problem. If you just make people pay for them via taxes, that's often a simple way to avoid that.<\|im_end\|>
<\|im_start\|>user Eli5: why does a person in remission end up getting the cancer back but at a more aggressive rate?<\|im_end\|> <\|im_start\|>assistant If a person in remission develops growth of their tumor, it will be made up of cells that survived their immune response as well as the treatment they received for the cancer. This is a rather obvious point, but it's important to note. The previous tumor(s) clearly had a majority of cells that were susceptible to the person's immune system and the chemotherapy/radiation/surgery that they received. The tumor that develops following remission is going to be made almost completely of cells that were not susceptible, or at least much less susceptible to those things. For this reason, it may grow back faster or metastasize earlier. It will also likely require different types of treatment.<\|im_end\|>
<\|im_start\|>user ELI5: How do birth control pills prevent pregnancy? How does it prevent pregnancy even if a couple does unprotected sex? (I’m aware it’s not 100% effective but still)<\|im_end\|> <\|im_start\|>assistant The menstrual cycle is controlled by hormones which make sure that a single egg is released and all the processes take place in the right way. What the birth control pills does is that they replace these hormones so that you get the same hormones and a similar menstrual cycle but without an egg. Essentially you are fooling the body into thinking there is already an egg on the way.<\|im_end\|>
<\|im_start\|>user ELI5:Butler's Gender Performativity I am trying to fully understand Judith Butler's theory of gender performativity and I would like some help.<\|im_end\|> <\|im_start\|>assistant The basic (and simplified) idea is that gender--what we think of as masculine and/or feminine--is performed in the ways we act, speak, dress, move, etc. and doesn't really exist outside of that performance. We learn how to perform this way from dominant culture and conventions--what someone might (incorrectly) call "normal male" or "normal female" behavior. But these "normal" qualities (and genders themselves) don't actually exist--rather, we are all repeatedly mimicking them and are rewarded for doing so (or punished for not doing so). We merely impersonate the qualities we've been taught match the gender we've been told we possess (like females being demure or males being aggressive) until those impersonations (and gender itself) become belief and seen as something natural and assumed. She so talks about drag and subversive gender performance, but that gets a bit more complicated. Is there a specific point you're stuck on?<\|im_end\|>
<\|im_start\|>user ELI5:How does the middle income trap work? My understanding is that the middle income trap describes countries that have risen from extreme poverty, but not into first world status. Malaysia is often cited as a textbook example. What is the prevailing though of why this happens.<\|im_end\|> <\|im_start\|>assistant when you have an economy that has a lot of workers that can be fairly low-paid workers (compared to more 'developed' countries), companies will start up factories there to take advantage of the lower costs. The people working there will happily do so because the pay is better than might otherwise have happened, so everybody seems happy. This influx of money creates a 'middle class', who aren't rich exactly, but have more money than the traditional working class. Wages increase (as they usually do), but eventually, another country is able to provide a workforce that is cheaper again which means the upward mobility in the original country stalls.<\|im_end\|>
<\|im_start\|>user Can one deny the existence or importance of metaphysics while remaining intellectually coherent? Hey all I sometimes find that there is a dismissive attitude towards metaphysics by some people. They claim either that the term refers to nothing meaningful, or that the field itself is incoherent or of no value. I am a lay person, so I am not skilled enough to evaluate this. But it seems superficially incoherent to me. Surely one most have one metaphysical framework or axioms from which to form their core beliefs of the world? Even if one is an ardent empiricist, if one doesn't, how can you even begin? .And further, isn't the rejection of anothers metaphysical framework itself a metaphysical position? Thanks so much in advance.<\|im_end\|> <\|im_start\|>assistant There's a 20th century school of philosophy called ordinary language philosophy and, as the name implies, they considered metaphysical theorizing to be a misuse of ordinary language, and they contended that metaphysical inquiry results in pseudo-problems that should be recognized as such and abandoned once we realize the misuse of language. This tradition has largely fallen out of fashion since Strawson died, but there are still some contemporary adherents, such as John Searle. So, yes, one can deny the importance of metaphysics while remaining intellectually coherent, as there have been well-respected and influential philosophers, most notably Wittgenstein (from whom the ordinary language school emerged), who have done so. However, their attitudes aren't dismissive, but rather a result of serious engagement and consideration of metaphysics. And you're correct that the above-mentioned conception of metaphysics is, itself, a metaphysical position. To say that one does not need a metaphysical framework is to be taking a position within the metaphysical discourse, rather than separating oneself from it.<\|im_end\|>
<\|im_start\|>user What are the philosophical solutions to "ship of Theseus" problem of identity? Is there evidence that replacement doesn't affect or change identity? Ship of Theseus is a thought experiment in which every piece of a ship kept in a harbor is replaced one at a time. The questions are: would the end result be the same ship or a new ship? If it is not the same ship; at what point did it stop being the ship of Theseus? If it is the same ship; would reassembling the removed pieces to form another ship result in another ship of Theseus? Surely the ship would not be in two places at once? What philosophies argue that the result is the same ship? And how do the philosophies defend their position that replacement doesn't affect or change identity? Rephrasing the thought experiment to improve relevance: our bodies grow and change. The old, worn out cells are replaced one at a time. The atoms that make up our cells and bodies too are replaced. Is the end result the same human from before or a new human? What philosophies argue that the result is the same human? And how do the philosophies defend their position that replacement doesn't affect or change identity?<\|im_end\|> <\|im_start\|>assistant > What philosophies argue that the result is the same human? And how do the philosophies defend their position that replacement doesn't affect or change identity? Some philosophers claim that being the same person is compatible with undergoing some degree of change, in particular, they deny that the growth or aging of their bodies carries any philosophical implication for whether someone is the same person or not. Losing a leg, same person. We identify people largely based on their physical features, spatio-temporal continuity and the relative stability of their emotional, psychological and moral characteristics. Loss of memory doesn't even disqualify many people from being the same person -- though their sense of their identity may be very different.<\|im_end\|>
<\|im_start\|>user [Action films general] If the protagonist actually throws a knife at someone, isn't there inherently only like a 20% change that the blade/tip is going to impact first? Getting hit in the chest with a knife handle would hurt, but it's not going to put someone out of commission<\|im_end\|> <\|im_start\|>assistant With a known distance, it's possible to get a lot more than 20%, closer to 80%. The range of possible distances is pretty small, so it's not inconceivable that Mr. Badass here has practiced across all of them. I hear it's all about the spin. Furthermore, a trained thrower is not particularly attached to knives. People have thrown axes, hammers, shovels and IIRC even nails, with nearly the same efficacy. Throwing knives are just more convenient and don't fall apart after three throws - a throw is a lot stronger than a simple stab. Throwing knives are typically made of a monolithic piece of steel.<\|im_end\|>
<\|im_start\|>user How long does it take an electron to orbit a nucleus?<\|im_end\|> <\|im_start\|>assistant It can be estimated from the uncertainty principle. Δx Δp ~ ~~h~~, so Δp ~ ~~h~~/Δx. The characteristic length scale of electron orbitals is a_0_, the Bohr radius. So the RMS momentum is like ~~h~~/a_0_. This is around 4 keV/c. Converting this to a speed, it's around 2000 km/s. This is for the ground state of hydrogen, for higher orbitals and nuclei with higher Z, they'll be moving faster.<\|im_end\|>
<\|im_start\|>user CMV: There is nothing wrong with other cultures eating animals we domesticate. E.g. asia eating dogs. Obligatory, For the purposes of this post I will predominantly use the example of dogs being eaten in asia because It is subjectively the most widespread and emotional example. In the same way that we breed and hold livestock in pens to be slaughtered and eaten on a mass scale there is nothing wrong with the same thing being done to cats or dogs. I see this come up a lot, the notion that chinese culture is ethically skewed because they eat dogs. This is fundamentally no different to you eating a cow. If you're disgruntled by the notion then it is an internal issue with yourself and your ethics more so then it is with another culture. In this case I believe that it is wrong to superimposed our western ethics on other cultures. I believe that it is taboo because we have, as a culture bread and domesticated Canis for agriculture, hunting and companionship. Likewise other religions may have developed sacred connections to pigs, cows etc. They have no right to infringe on what we believe and nor do we them. I do not know the popularity of this perspective, wit I welcome criticism, healthy debate and hope to reach a common understanding. EDIT 1: I feel compelled to make this clear, not everyone in asia actively participates in the example I have used, in fact in recent years it has become far more taboo. However like I stated this is the most emotive example of cultural differences between the east and west and subsequently the most effective in initiating debate. EDIT 2: My opinion had been skewed, I appreciate the effort and time you all have put into your comments. The rationalisation is that dogs, like cats are working animals, they have been bred to work and provide companionship, and therefore to eat them, would be inefficient. I think that is the route for the argument againsed eating dogs, at least in this isolated example I can appriciate that logic. However I do not believe that it is fundamentally too dissimilar to eating any other animal, if the argument is purely one of efficiency then we would only farm and eat genetically engineered lumps of muscle. We dont. We have an entire pallet of meats and foods, and therefore upon that basis I do not believe that the west can claim any sort of moral high ground. Subsequently, my opinion on the matter had been expertly debated, but still holds. I'm not debating wether eating meat is right or wrong, I'm debating wether eating meats in the west is any different to the meats in the east.<\|im_end\|> <\|im_start\|>assistant (I am arguing through the utilitarian/harm-reduction axiom: the most ethical action will most greatly increase net happiness and decrease net suffering) In Indian culture, an even more restrictive set of axioms exists. Beef consumption and cow slaughter are (rightfully) taboo, and other meat consumption and animal slaughter are (rightfully) discouraged. So it's not even universally acceptable to eat beef. &#x200B; >In the same way that we breed and hold livestock in pens to be slaughtered and eaten on a mass scale there is nothing wrong with the same thing being done to cats or dogs. Sure, eating cats or dogs is no worse than eating Western livestock, but it is still an unethical act. You use a false premise (depending on your axioms): it is ethical to slaughter and consume sentient animals. This is unethical as the total happiness gained from slaughtering and consuming another sentient animal will not exceed the total suffering as a result, except for life-death situation, food shortage, etc. (which is highly uncommon in a modern context). Western cultural norms do not justify the slaughter of Western livestock (especially in current factory farm environments), therefore they do not justify the slaughter of other sentient animals.<\|im_end\|>
<\|im_start\|>user Does String Theory deny the Standard Model?<\|im_end\|> <\|im_start\|>assistant It doesn't "deny" the standard model, it has to explain all observations consistent with the standard model at the appropriate energy levels. It does however, deviate from the standard model at high enough energies. Superstring theory predicts particles that aren't in the standard model, which haven't been observed yet.<\|im_end\|>
<\|im_start\|>user What caused the massive spike in oxygen content in Earth's atmosphere 300 Million years ago?<\|im_end\|> <\|im_start\|>assistant The success of land plants as forests of tree-like vascular plants led to the spike in atmospheric O2 in the Carboniferous Period. This and the rapid burial of plant material in swamps that became world wide coal measures. The fossil evidence for this is the rise of very large insects, such as meganeura a dragonfly the size of a small bird, allowed because the capacity of the tubes that insects use to breathe was limited but could be offset for larger individuals by the higher O2 concentration.<\|im_end\|>
<\|im_start\|>user How are the sine and cosine functions derived? I understand that for certain angles, using the relationships between the sides of 30-60-90 and 45-45-90 triangles can be used to find the value of sine and cosine. But what I don't understand is how those functions are found for different angles, like 11 degrees. In practice you use a calculator, but the calculator's answer has to come from somewhere.<\|im_end\|> <\|im_start\|>assistant There are a few different ways, but one way is to look at the circle. Take a unit circle in the x-y plane (i.e. the graph of x^2 + y^2 = 1). Any point point p on the circle forms a right triangle: the three sides of the triangle are formed from the line from the origin to p (Line R), the perpendicular line from the x-axis to p (Line X), and the perpendicular line from the y-axis to p (Line Y). Define θ as the angle between the x-axis and Line R. Then, define cos(θ) as the length of Line X and define sin(θ) as the length of Line Y. This is one way of defining sine and cosine.<\|im_end\|>
<\|im_start\|>user ELI5: Why do people start to hallucinate while they are sick or dying? Context: A friend of our family was in the hospital for a very long time and also was in a coma for 3 months. While his wife was sitting next to his bed he kept starring to the wall. When she asked why he is doing it he told her a person ("Death/Reaper") came in three times today and he told that person to go away since he is not ready to go yet. His wife started crying in the hallway and talked to his doctor. She told her that three people died the night before. I guess it's just a coincidence, but I keep hearing those stories from people I know and I also come across them on the internet. I am pretty sure many people just come up with the stories for the clicks, but not all of them are made up. What is the explanation for this?<\|im_end\|> <\|im_start\|>assistant The term for this is delirium. Delirium is quite complex and is defined by confusion, changes in awareness and attention. There are many things that cause delirium some of them are direct injury to the brain (stroke, brain infections, etc). Other things (infections, liver disease, medications, prolonged ICU stays) have been known to cause delirium but we don’t exactly know why. Dementia and aging are definitely known risk factors for delirium because we lose our brain volume as we age. There are some theories out there but it is all poorly understood. The best thing we have for it is treat the underlying cause (if there is one) or try and control symptoms. It’s a good question but unfortunately one we don’t have all the answers to.<\|im_end\|>
<\|im_start\|>user Why can we calculate (not measure) pi? Understanding that pi represents the ratio of circumference to diameter of a circle, my question is regarding one (of several) methods to mathematically calculate the value of pi. pi / 4 = 1 - 1/3 + 1/5 - 1/7 + ... As you extend this equation it gets closer and closer to the value of pi. Admittedly it takes a ridiculous number of terms to extend it more than a few decimal places, but presumably it would continue to gain accuracy as you added/subtracted an infinite number of fractions. My question: WHY? How does this equation relate to the characteristics of circles? Is something more profound at work? Enlighten me, please!<\|im_end\|> <\|im_start\|>assistant There is a way of approximating functions called a Taylor series expansion, where you add polynomial terms of higher and higher order to approximate the function. For example, the Taylor series of the cosine function is 1-x^2 /2 +x^4 /24 -x^6 /720... and if you calculate some values for x in radians, you'll find it's accurate if x isn't too big. You can figure out the terms with basic calculus. From trigonometry, we know that the tangent of pi/4 radians (45 degrees) is 1. Thus, the inverse tangent of 1 is pi/4. The Taylor series for the inverse tangent function is x-x^3 /3 +x^5 /5 -x^7 /7 ... and if you substitute x=1, you're just left with that continued series for pi/4.<\|im_end\|>
<\|im_start\|>user ELI5: Why don't blood vessels sort of kink when we fold our knees/elbows? Kind of like a hose<\|im_end\|> <\|im_start\|>assistant 1. The outside of each blood vessel is made of a material that has the right blend of firmness and flexibility. 2. Most blood vessels are surrounded by soft tissue that will yield first, or hard things (like bones) that will protect them from some of the pressure. 3. The interior of blood vessels is pressurized by the action of the heart.<\|im_end\|>
<\|im_start\|>user ELI5: Why are MRI's so huge? why didn't they get smaller in size like computers did?. Computers went from the size of a room to fit in our pockets, so why are MRI's any different?.<\|im_end\|> <\|im_start\|>assistant MRI's require a strong magnetic field around your body. Making a strong magnetic field requires a large magnet. In some cases, the technology has gotten better and there are "open MRI" machines where what can be made smaller has been, and you no longer travel through a tunnel to get scanned. At the very least though the machine must be able to generate a magnetic field around whatever is being scanned (such as your body).<\|im_end\|>
<\|im_start\|>user ELI5: What is the difference between Drive, 3, 2, and 1, in an automatic car? Very confused about this.<\|im_end\|> <\|im_start\|>assistant When you choose Drive, you are telling the transmission to choose whichever gear it feels is most suitable for the driving condition at any moment. When you choose 1, you are limiting the transmission to the use of first gear only. 2 allows the use of first and second; 3 allows the use of the first three gears.<\|im_end\|>
<\|im_start\|>user Could someone please attempt to explain entropy to me in a fluid dynamics context? I have recently started a job as an aerothermal engineer and have had trouble understanding exactly what entropy is in a physical sense. I've encountered it in a few cases, for example, viewing entropy plots to locate pressure shocks over aerofoils, but I can't grasp exactly what it is.<\|im_end\|> <\|im_start\|>assistant Entropy (both in computer science and physics) is a measure of the number of possible states of a system. Creating entropy somewhere means you have taken a certain path in reality, out of a great number of others. The greater the entropy increase, the greater the number of possible states your system can have. The sheer number of these new potential other states basically makes it impossible to go back to a point where the number of states were comparatively hugely smaller. Creating entropy means there is no going back in time. Entropy can also be seen as a measure of disorder: the more the possible states of a system, the more you'll see random behavior appear. When your fluid is laminar, little entropy is being created: your fluid has a very low number of ways to evolve. When your fluid is not laminar, when there are pressure shocks, a great number of possible states are being created. And you're likely to see turbulences. When plotting entropy, you are basically viewing where the action takes place (where a single reality is chosen over a great number of potential states).<\|im_end\|>
<\|im_start\|>user ELI5: Why do fast food and casual dining places need to nickle and dime us on some things but not others? Taco places charge for sour cream and guacamole but you can take as much hot sauce as you please. Burger joints make you pay for dipping sauces but freely dispense ketchup, mustard, and even mayonnaise. Wing places will add a price (sometimes without telling you) for ranch and bleu cheese while again giving away other free condiments. Is this to actually justify different costs or is it a money grab to squeeze every penny possible out of us?<\|im_end\|> <\|im_start\|>assistant There are things that are considered traditionally part of the dish and things that are considered additional. A burger isn't a burger without the dressing and in order to compete you have to supply those things for free just like every other burger joint. Dipping sauces are part of a different menu item so to get it you need to pay for the difference in cost. Guacamole and sour cream are significantly more expensive than salsa and they do not keep for anywhere near as long. Taco Bell can make salsa by the truckload and distribute it to their stores as needed. It really doesn't cost them much to produce and keeps for a long long time so they can buy ingredients when they are cheap, produce a ton and then wait out winter months or bad seasons. Guacamole takes actual manual prep and spoils very quickly as does sour cream. The price for avocado and milk also can change drastically in short periods of time so not including them in the base price of the item makes it easier to alter menus and keep things standard across the chain. Same thing applies to the wing sauces you mentioned.<\|im_end\|>
<\|im_start\|>user ELI5:Why do military vehicles have a longer period of usage than other vehicles? By this I mean some planes that the USAF use were made in the 60s yet we are still using them today; however there are practically no commercially used planes made in the 60s anymore. Why is this?<\|im_end\|> <\|im_start\|>assistant Maintenance. Lots and lots and LOTS of maintenance. Most people don't realize just how much maintenance all types of military vehicles--and particularly aircraft--require. It's not at all uncommon to find aircraft, even new aircraft, that require tens or hundreds of hours of maintenance for every hour of flight time. In the case of B-52s, those were all built between 1952 and 1962, and there are ~70 of them still flying. Damn near everything besides the airframe has been replaced multiple times, but those planes were just well-built to begin with.<\|im_end\|>
<\|im_start\|>user ELI5: How sharp is paper? It doesn't take a lot to get a paper cut, which makes me think it must be pretty sharp, especially because paper isn't all that rigid. I'm not totally sure how to define "sharpness" but is it comparable in sharpness to a knife? If it were more rigid, where would that place it?<\|im_end\|> <\|im_start\|>assistant Sharpness, until recently, has not been a very well defined term. Unfortunately, explaining sharpness is actually more complicated that an ELI5 because it requires an understanding of fracture mechanics. The good news is that your question can be answered without actually defining sharpness! The first thing to understand is that being "sharp" entirely depends on the shape of the thing doing the cutting. It's a common misconception that "sharpness" depends on hardness, but it does not (for anyone interested, hardness affects how sharp something can stay, but not how sharp it is). For this reason, butter that has the exact same shape as very hard steel knife is technically just as sharp as the knife. So why does this make a difference? Because this also means that if you had a piece of steel that was as thick as a sheet of paper and had a microscopically flat edge like paper (assuming that's the case), it would be exactly as sharp as the paper itself. It may not be intuitive as to what that steel piece would be like, so you can imagine it'd basically be like a very dull razor. In other words, paper is not very sharp because, as thin as it is, its edges are still very broad. So if paper is not sharp, why the paper cuts? Think about this: if the paper wasn't gliding across your finger and was simply pushing directly into it instead, do you think you'd still get a paper cut? Probably not, since we'd end up with many, many more paper cuts if we could get them simply by pushing. But when the paper glides over your finger, it manages to cut well. The key difference is that it's much easier to break skin by tearing it along the surface than it is to break it by pushing directly into it. You ultimately don't need all that sharp of an edge to cut yourself by drawing the edge across your skin; paper will do just fine!<\|im_end\|>
<\|im_start\|>user ELI5: Why does the United States have more prisoners per capita than any other country?<\|im_end\|> <\|im_start\|>assistant While this is an extremely complicated question,the most significant contributing factors are "the war on drugs", mandatory minimum sentences, and three strikes laws. These function to incarcerate people for what would otherwise be considered less serious offences.<\|im_end\|>
<\|im_start\|>user I believe that rather than spending money on programs for the severly mentally disabled, schools should put money into programs that can help develop those who will eventually contribute to society. Please CMV I go to a high school in the U.S that has an extensive program for those with severe mental disabilities. I'd say there are at least three seperate classrooms and about 20 people who are employed to take care of them. I think that this is a waste of money that could be used on extracurricular programs to help develop students who will eventually contribute somthing to society. Also, when I saw mentally disabled I mean students with disabilities that cause them to lack any conceivable form of communication or intelligence that allows them to contribute anything. I'm not really sure how to phrase that, but I'm thinking of anyone who falls into the very low IQ range (70-) or is completely unable to express intelligent thoughts that they may or or may not have. I do, however, understand that people with minor learning disabilities (ASD, aspergers, etc.) are not only able to contribute to society, but are sometimes incredibly intelligent.<\|im_end\|> <\|im_start\|>assistant The goal of those programs is to help those with significant mental impairments function properly, so that they can also be constructive to society. Essentially, it's to help them get to that level of functionality that you describe those with less significant disabilities as having, and you suggest you don't have much of a problem with them. Plus, not having these programs would be worse for society. If the mentally impaired children you mention were placed in classrooms, the ability of the class to function would be compromised, due to the amount of monitoring required for the lower-functioning students. This would mess up the ability for all students to contribute to society, which it seems you favor. And if they simply stay at home? Then an enormous economic burden is placed on the family who must have to monitor and support such youth - possibly forever, seeing as they might not have the knowledge or skill to help mentally disabled children function well. Economic stress and possible unemployment, for families who only wish to help their mentally disabled children.<\|im_end\|>
<\|im_start\|>user ELI5:Why do law firms use the partnership model? I'm sure the partnership model works in a lot of situations, but what makes law firms so unique for this model to be the standard? Why aren't they run like 'normal' businesses with an owner/shareholders and salaried employees?<\|im_end\|> <\|im_start\|>assistant In modern times, it is legally restricted how lawyers can organize themselves--it's viewed as a bad thing for an attorney to be under control of a non-attorney shareholder for example, considering his special duties toward clients. But that doesn't really answer the historical question. A lawyer is a typical example of a professional. He trades on his reputation, and it's all about his abilities. You cannot separate the service from the attorney providing it--being represented by John Doe is not the same as being represented by Richard Roe. So it makes sense for lawyers to be business for themselves, albeit with clerks or secretaries assisting them perhaps. A partnership is an extension of this model--you've got lawyers working together, but they're still individuals with clients specific to them, they just pool some of their capital and other business sources.<\|im_end\|>
<\|im_start\|>user Why do we expect extraterrestrial life to only be carbon-based and rarely consider alternatives? Why do scientists seem to assume that life must be based on carbon? I understand the organic chemistry reason, and that we are carbon-based here on earth, but isn't it possible that "life" could have evolved relying on different materials? Related, why do we focus our search and our expectations on carbon-based extraterrestrial life? Thanks!<\|im_end\|> <\|im_start\|>assistant We may only know one kind of biology, but we know an awful lot of chemistry. And Carbon is the right kind of element to make the very complex chemicals and rapid chemical reactions that really distinguish "life" from non-life. Similarly, water is the right kind of solvent for "life" to occur in. There may be other cases out there, but carbon and water are exceedingly good candidates, chemically speaking, to form life<\|im_end\|>
<\|im_start\|>user ELI5: Why is it that alcohol does not have to have the ingredients or nutritional facts printed on the bottle?<\|im_end\|> <\|im_start\|>assistant It all depends on whether something is regulated by the Food and Drug Administration (FDA, part of the Department of Health and Human Services) or the Alcohol and Tobacco Tax and Trade Bureau (TTB, part of the Treasury Department.) Only FDA-controlled items are required to have nutrition labels. For TTB beverages, it's voluntary. There have been efforts to standardize this, but nothing's ever come of it. The historical reason for this split is simple: Alcohol has always been an important source of government revenue, much more so than food. Distilled spirits (aka hard liquor), wine, and malt beverages (aka beer and malt liquor) are all under TTB control. This creates some peculiar exceptions. Gluten-free "beer" made with something besides malted barley is an FDA-controlled beverage with a nutrition label. Hard cider is just as alcoholic as beer, but it's not malted, so needs a label. (For some purposes, it's apparently treated as wine.)<\|im_end\|>
<\|im_start\|>user ELI5: Why can't we use all the excess skin from people with extreme weight loss to treat burn victims? With the technology surrounding grafting, why can't we take the huge amounts of skin that come from the formally obese and graft them to victims that have suffered severe burns? If skin 'typing' is an issue, it seems we could setup a global exchange - there is demand on both ends it would seem?<\|im_end\|> <\|im_start\|>assistant Your cells have specific proteins on their membranes that serve as markers for your immune system to differentiate self from non-self. These proteins can vary from person to person, although they serve the same function. The reason you typically graft skin from yourself is that the skin will not be rejected by your immune system, where as if you used someone else's there's a very likely chance it will be rejected and cause an immune response.<\|im_end\|>
<\|im_start\|>user ELI5 how we can determine that tiny particles like quarks and neutrinos exist, but cannot determine what is ultimately the source of matter.<\|im_end\|> <\|im_start\|>assistant Because, in general, it's easier to know something exists than to know how it exists. We can determine they exist 1. Because we can break things apart into them and 2. Because we can see how they interact with things. But, of course, we can't actually see them, because they are so small, and we can't break them into smaller parts, at least not that we know of. So while we know they are there, we don't know what they are. I assume that was what your question was, but the wording is weird.<\|im_end\|>
<\|im_start\|>user [Star wars scp universe] what would the classification and containment procedures be for Darth Vader? assuming he brought his lightsaber with him<\|im_end\|> <\|im_start\|>assistant Class: Safe The Force is not known to permeate the Milky Way galaxy, so a Vader on Earth is just a formidible swordsman with a plasma sword. He can be relatively easily subdued at range using any standard weaponry (lethal or less-lethal). Containment can be any room with a door strong enough to withstand his cybernetic strength.<\|im_end\|>
<\|im_start\|>user How do I cite a transgender author's name Hi, everyone! I am trying to cite an old article by an author who has since come out as transgender and changed their name. Do I cite the text using the name which appears on it (essentially deadnaming them), or do I use their new name? I feel like this is kind of a tricky situation because, on the one hand, I want to respect the author's new name, but I also want my citations to be "correct" for plagiarism's sake.<\|im_end\|> <\|im_start\|>assistant Here’s what MLA 9 (idk about other style guides, sorry) says in section 5.15 If you are writing about or working directly with an author whose name changed and you know they do not use their former name in references to their work—for example, trans authors—list their works under the name they use, regardless of the name that appears in the source. Do not supply information about the name change or cross-reference entries, and avoid using the former name in your prose.<\|im_end\|>
<\|im_start\|>user What's the best explanation for the meaning behind this famous Nietzsche quote? "He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." The first sentence is fairly straightforward but I've long thought about the second one and have struggled to understand it. Thinking maybe I don't understand Nietzsche enough to understand this? I figured the much smarter people in r/askphilosophy could help. I'm sure there's a lot of diverse opinions, would love to hear them all.<\|im_end\|> <\|im_start\|>assistant Nietzsche, like Hegel, is interested in the dialectical nature of the self, how the self and its other mutually inform one another. It is not possible to quarantine yourself in an absolute manner from what you are setting yourself against (though it's a huge psychological temptation). There is always the risk of becoming a monster when fighting monsters. But Nietzsche provides his individualist twist to this dialectical notion of the self by adding that, even if you were to set up your other as an abyss rather than a monster, even if you were to gaze into this big inert hole rather than fight against a bad other who is out to get you, even if you were to choose as your other NOTHING, a big lack of objects all smoothed together, an abyss, the dialectical nature of the self would still be there at the end of the tunnel, because, at the end of the day, your fight with the monster wasn't all about the monster (though that's another huge psychological temptation that Nietzsche is trying to push back against), your fight with the monster was also self-revelatory, i.e. the animating factor in our relationship with monsters is us saying "we are not that monster". So even if you stop fighting and just passively gaze into nothingness, even if you choose NOTHING as your object, the object will still be yammering on and on and on at you, because it isn't about the object dummy, it's you, it's self-creation that is at the heart of geist, that's where otherness comes from. It's not about the Sun, it's about for whom the Sun shines. Our dynamic connection with the world is more about us than it is about the world; the world talks to us even when we choose the deadest thing in the world imaginable, an abyss, because it isn't the world that's doing the yakking when the world is yakking, it's us, it's our self-creation. We love our enemies! Maintaining yourself against enemies, distinguishing yourself from what you are not, is the essence of selfhood. But it's us, it's us, it's us, we are the ones doing it. That's what the abyss brings out. The other yaks on and on even when there is no other. The self is its relation to itself as it pours out into the other, it is a self repelling against itself that pushes out as the other, etc., etc. It's geist that creates otherness and it's geist that can resolve it. Nietzsche thinks this could occur in an individual Superman purged of resentment. He would be cool with the fact that humans are like a yammering abyss, and still go on self-creating anyway without a worry in the world about such things.<\|im_end\|>
<\|im_start\|>user [Biology] How do antibodies work and why has there never been a case of bacterial resistance to such antibodies?<\|im_end\|> <\|im_start\|>assistant Antibodies, also called Immunoglobulins, are proteins that are secreted in response to an antigen, which is most commonly a protein of the pathogen, but can also be against a toxin. After an immune cell of the Innate Immune System (the first responders), a Macrophage for example, engulfs and destroys the invader, it then presents a piece of it on the cell-surface via a molecule called the Major Histocompatibility Complex (MHC). In the case of Antibody production this is then presented to a B-Cell which turns into a Plasma Cell to produce antibodies specific to this antigen. Antibodies can then work in two ways; They can neutralize the target directly by blocking important proteins on the surface, or they can prime the target for easier attack by the immune cells - The latter is called Opsonization. Bacteria does not become directly "resistant" to antibodies, but there are several ways to avoid it: Mycobacterium tuberculosis, causative agent of tuberculosis, can survive and even replicate inside phagocytes like macrophages, by disrupting the fusion of the Phagosome with the Lysosome, which is a "digestive" mechanism of the cell. The Lysosome contains various hydrolytic enzymes to break down the pathogen. Sometimes members of the same bacterial species have different serotypes, which means that 2 strains cause 2 different antibody responses and are not affected by the response to the other. Other pathogens, like the parasites that cause Malaria, can change their surface proteins when they replicate to avoid circulating antibodies.<\|im_end\|>
<\|im_start\|>user CMV: People who can't afford kids shouldn't have them. I've seen this sentiment expressed from time to time and quite to my surprise it often generates a lot of anger and controversy. Why? According to the USDA it costs around $230,000 to raise a single kid from 0 to 18, and that figure doesn't even include college. That figure averages out to a little over $1,000/mo. EDIT 4: I brought up these figures more to highlight the so far practically unargued point that having kids is expensive. As several people have pointed out, using the $230,000 figure is a bit misleading because that's just an average (some would say over inflated) for a certain category of people in one country; some kids will take less to raise, some will take more. So to kind of move away from a specific number I'd rather frame this issue in a series of questions. Questions like: can you afford to feed your child three meals a day? Will you be able to afford to house and clothe your child? Will you be able to cover healthcare costs when you child is sick, injured, or just needs routine check-ups? Will you be able to pay for some baseline extracurricular activities for your child so they can grow up to be a functional and well rounded adult? Will you be able to be present as a parent for your child or will you be too busy working three jobs? If the answer is "no" to these sorts of questions, that's what I'd define as not being able to afford children, not a specific $/mo. If, say, it was possible to engage in an 18 year lease agreement (one it's almost impossible to get out of) for a quarter of a million dollar car, costing the driver $1,000/mo for almost two decades, it would be a totally common sense and uncontroversial thing to say that people who cant afford that lease, particularly poorer and struggling people, should not enter that agreement, much less two, three, four, five + seperate agreements at $230,000 a pop. If someone is broke and struggling but also was leasing an Aston Martin and a Lamborghini, youd probably think they were making very poor financial decisions. But swap out that luxury vehicle with a child or three and suddenly people get upset when you suggest they're making poor decisions. Why? If anything, I'd think that it'd be better for poor people to pay for the car than the kid - having a kid, even beyond the sheer cost, makes your already struggling life even harder arbitrarily, and also worsens the quality of life for the child i.e. another human being; a luxury vehicle isn't going to wake you up crying every night, or your job doesnt have to be structured around what time the car gets out of daycare; the child's quality of life, in terms of health, academics, enjoyment, etc. is obviously lessened by having parents who cant actually properly afford their existence. And then, because (rightly) we dont want children to suffer unduly or die due to their parents irresponsible procreation choices, society has to step in and help foot the bill for their wellbeing. I'm not opposed to this happening, but it is worth noting it wouldnt generally even have to be a thing if people who cant afford kids didnt have them. Also I'm not advocating for any kind of mandate, ban, or law. I just think it's a shitty financial decision. I think the same of a lot of financial decisions, but for whatever reason it seems there is pushback when these poor financial decisions pertain to children... I've never seen someone get up in arms over the suggestion that people who are struggling and poor probably shouldn't invest in bad timeshare contracts or whatever. (EDIT 6 was bolding this for emphasis - several people have responded like this paragraph didn't exist) Y'all know what to do. Cheers. EDIT 1: Should also note I'm viewing this subject through a lens of a concurrent, developed nation, particularly the US, which is where I live. Obviously in other parts of the world $230,000 could be enough to raise a thousand kids. EDIT 2: We are currently experiencing higher than normal response volume. Your reply is important to us. Please be patient and a certified OP will be with you as soon as possible. EDIT 3: One delta awarded so far for someone pointing out the utility and practicality of having children to stave off a low birth rate which is vital for a strong and functioning economy. My view was very much focused on individual choice and I hadn't considered societal need. EDIT 5: Many people are bringing up that I ought to be more focused on creating a society where everyone who wants kids can afford them, and people have access to the education/birth control aspects of family planning. I don't disagree with those goals at all. BUT, until we create that society, if we ever do, we ought to be wise about the decisions we make in the current system, which is the gist of the OP. EDIT 6: Frankly I'm not going to be able to get to all these replies, but there seem to be plenty of people chiming in from both sides of this issue, so hopefully this discussion will continue! I'll keep at this until my laptop battery dies (currently at 52%) and then I'm calling it quits for at least a few hours. Thanks to everyone for the good conversation so far.<\|im_end\|> <\|im_start\|>assistant 1) By the time they grow into working age adults, they will on average put more back into the economy than they took out. 2) The economy needs a growing population to function. 3) Therefore the government subsidizes childbirth, even for the poor, by footing some of the expenses associated with having children. The government should be doing more. The more spent on children early on, the more productive they will be later on.<\|im_end\|>
<\|im_start\|>user ELI5: Gases in space, do they form little spheres like tiny planets or move like earth clouds. How do they keep themselves together?<\|im_end\|> <\|im_start\|>assistant The short answer is gravity. Gravity exists between any two objects but it is weak unless there is a lot of mass. In the absence of any other forces a gas, or any other material for that matter, will form a sphere because of those gravitational forces. If the cloud is small enough it will be subject to other forces and won't be really spherical, but with enough size it will keep its shape more. Jupiter would be a good example of that.<\|im_end\|>
<\|im_start\|>user Can you Find new prime numbers by multiplying all of the known prime numbers and adding 1? Our teacher showed us the proof to that there is an infinate number of prime numbers by using Euclid's theorem. If you add 1 to the product of all known prime numbers is it garanteed to get a new prime number? And if so why are people still looking for new prime numbers?<\|im_end\|> <\|im_start\|>assistant If you multiply all known prime numbers and add 1, you won't necessarily obtain a new prime number. Another possibility is that you obtain a number that is the product of prime numbers that are all larger than the set of numbers you multiplied. As an example: Suppose we consider 2, 3, 5, 7, 11, 13. If you multiply these and add 1, you obtain 30031, which is not prime, but rather the product of 59 and 509, both of which are prime numbers. So the application of Euclid's Theorem is not a shortcut to finding new prime numbers. But it does guarantee that there are always more prime numbers to be found. So why do people still look for prime numbers? Here it's not so much the destination that matters, as it is the journey. The efficient computation of prime numbers can have important applications in computer science (for example in encryption). Researchers that compute extremely large prime numbers aren't that interested in the actual number they find, but more in the methods used to find it.<\|im_end\|>
<\|im_start\|>user ELI5: Why when we think about breathing we start breathing 'manually'? And how do we forget about it suddenly 'automatic' breathing starts? Thanks!.<\|im_end\|> <\|im_start\|>assistant Breathing is regulated by two different pathways, an automatic center that originates from your brainstem that controls your natural breathing when you are not actively thinking about breathing. There is also an area that comes from your cortex allows you to have active control of the muscles that are related to breathing (your diaphragm, your intercostals, your abs). When you actively try to take a deep breath/breath harder, you are overriding your autonomic breathing center, and actively using more of your secondary respiratory muscles.<\|im_end\|>
<\|im_start\|>user [RPGs] I just spent the afternoon walking around beating monsters to death with a club but for some reason I seem to have improved unrelated skills like bartering and lock picking... How does that work?<\|im_end\|> <\|im_start\|>assistant While engaged with monotonous physical activities, sometimes the mind wanders, reflects on past experiences, and explores the possible answers to lingering questions. I imagine you rehearsed some conversational skills in your head and gave serious thought to the engineering behind popular locking mechanisms of the time period.<\|im_end\|>
<\|im_start\|>user ELI5:Why is Pi so special and how was it discovered?<\|im_end\|> <\|im_start\|>assistant Pi was discovered initially as the specific ratio of a circle's circumference to its diameter. They determined that the exact ratio was not a simple fraction, though they were happy to approximate. As they explored mathematics, they determined that this ratio came about with surprising regularity, due to it's natural relation to circles and spheres.<\|im_end\|>
<\|im_start\|>user Where to study Psychoanalysis?? So I’m in my last year as a Philosophy undergrad, and I’ve become massively interested in Psychoanalysis, mainly through Deleuze&Guattaris critique thereof... so I’ve been reading a load of Freud and Lacan, and I’ve decided I want to focus on this in my masters, but I’m not sure where (UK or mainland Europe) is best to study Psychoanalysis at a postgrad level?? Thinking in terms of renowned schools and places that are regarded as the best places to study it... I’ve looked at Birkbeck and UCL in London, but would appreciate any tips!! Thanks xx<\|im_end\|> <\|im_start\|>assistant I feel like you should ask this at r/psychoanalysis, there are certainly some clinicians over there who would be willing to suggest something. Paris VIII is the obvious answer, but if you don't speak French proficiently you must look for an alternative.<\|im_end\|>
<\|im_start\|>user ELI5 why are some metal objects cast while other are forged?<\|im_end\|> <\|im_start\|>assistant Depends on the application. If the part is made in large quantities, then casting is probably more efficient and cheaper.if the part is very complex, then casting is also easier. However, cast metal can be 'short' - meaning it has a crumb texture inside, like a shortbread. This can affect its strength. Forged metal is usually tougher, so better suited for parts that carry a lot of stress. Any industry that manufactures a metal part will weigh up the needs of the application versus cost, and figure out the best process. It tends to be the case that cost cutting will result in parts being cast when they should have been forged. Cheap lever corkscrews...the handles always break because they have been cast and aren't tough enough for the physics of leverage.<\|im_end\|>
<\|im_start\|>user why is it so important to keep trauma victims awake/alert on the way to the hospital, as in how does that aid in their chances of survival?<\|im_end\|> <\|im_start\|>assistant More often then not, its easier to monitor the condition of someone whose conscious. By simply talking with the first responder we know they have a viable airway and are breathing. A comatose patient is difficult to assess, as they cannot pinpoint the location of the injury, tell the medical staff how they feel, and communicate any changes in their condition.<\|im_end\|>
<\|im_start\|>user ELI5 why Colors Fade in sunlight? What actually happens to the color? Does it dissipate into the air somehow?<\|im_end\|> <\|im_start\|>assistant The photons of ultra violet light from the sun interact with some chemicals that are used to create dyes and pigments (i.e. colors) in a way that causes the chemicals to change and stop having the color. The energy of the photon causes certain bonds between atoms in the dye molecule to break.<\|im_end\|>
<\|im_start\|>user ELI5: What's happening between EU and Switzerland? I've read something about immigration on Switzerland and punishment from the UE but I'd love a simpler and less subjective explanation.<\|im_end\|> <\|im_start\|>assistant In order to enjoy free trade between Switzerland and the EU they have to abide by a number of rules that apply to EU countries as well. One of which is free movement of people. Since they are putting a stop to immigration, also from people who live within the EU, they risk blowing up the free trade agreement since they don´t play by the same set of rules as EU countries do anymore.<\|im_end\|>
<\|im_start\|>user ELI5: Why does meat usually taste better when it's cooked?<\|im_end\|> <\|im_start\|>assistant Cooking is a way of outsourcing digestion. The heat breaks down the proteins and carbohydrates so your body doesn't have to. Carmelization of those carbohydrates produces a more pleasing flavor. The proteins become denatured and natural enzymes that might spoil it get destroyed.<\|im_end\|>
<\|im_start\|>user [Bioshock Infinite] How does Booker not rip his left arm off when using the Sky-lines?<\|im_end\|> <\|im_start\|>assistant The skyhook is designed based on two principles, ensuring that your wrist doesn't break, and relying on forward momentum. The skyhook is designed with an arm brace, so that the shearing force doesn't do some damage. But the important thing is that you have to be moving in order for the thing to work. That forward momentum transfers the force that would rip his arm off into moving forward. Physics, basically.<\|im_end\|>
<\|im_start\|>user [Star Trek] What are some common strategies for the Kobayashi Maru simulation?<\|im_end\|> <\|im_start\|>assistant Common strategies? You might as well ask me to give you the scientific numerical breakdown of the Lourve? The KM hasn't been a standard test for ages. No its about adapting, improvising, innovating, exploiting and creating. We don't mark you for completing it, we mark you for how far you will go. For how much you can push the confines of your situation to come out on top? Hacking the program isn't even an offence, but a good hack shows us that you know what its like to be forewarned, and the level of ICE we've got on the network alone requires some serious genius to break. If you hack it to win, thats fine because you chose your path to completion based on your ability to game the defining controls yourself. Winning and losing are pointless when you are destined to fail, in these circumstances something changes. Old veterans have seen it, anyone who's come out of the rough end of an almost last stand have lived it. That moment where you can line up all of the variables and not be restricted by false barriers like chain of command or rules of engagement. So what if you jettison several drive cores to wipe out the whole fleet and the KM? Or maybe trying to actively break the computer security on the Klingon FFI beacons so they fire on each other? Heard about the cadet who used an oddball theory on warp drives to destabilize localised warp space cause the incoming warping ships to split at the molecular level when they tried to enter the radius of the effect? He's now in top secret R&D. One plucky cadet convinced the bogies to defect to the Federation. Hack the system, play out some kind of cultural blackmail, push the limits of our engineering and science, feint and decieve them, fight to the bitter end by adapting and making up tactics on the fly to cope with the oncoming doom. These are all how you pass the KM. Do you know how you fail the test? You try to save the KM by the book. Anyone can follow SOP, thats the bloody point of it, but the KM exists because SOP will fail. When we setup the KM for a new batch we don't want to see textbooks answers we want to see what fresh new minds do when given the impossible to achieve and thrashed and thrashed until they damn well succeed.<\|im_end\|>
<\|im_start\|>user Does language affect learning and studying? What I mean by this is do different languages explain concepts better and can you learn something better in another language. Say person A is equally fluent in 2 languages and the person is studying something which has specific terms and concepts. Is it better to study with one language than the other. Could it be different when studying in different ways(viewing, listening).<\|im_end\|> <\|im_start\|>assistant Yes. For example, studies have shown that people who's language does not have words to describe spatial relativity have a very hard time learning spatial concepts. They even do poorly when tested remembering where something is in a room. Conversely, people who speak languages with more words for the color blue have been tested and are able to differentiate between similar blue colors with significantly more accuracy than English speakers. So yes, language does affect how we learn, study, understand, and even perceive the world.<\|im_end\|>
<\|im_start\|>user Why can tenured professors teach poorly and stay employed?<\|im_end\|> <\|im_start\|>assistant The whole point of tenure is so professors can concentrate on research. The professors primary job isn't to teach, but to make advancements in his or her own field of study. Teaching is like a side gig for tenured professors.<\|im_end\|>
<\|im_start\|>user With the talk of a functional bionic eye, would hallucinogens impact the users perception just like a real eye?<\|im_end\|> <\|im_start\|>assistant Oh yes. The physical tools of perception (lens, retina etc) are merely the first step in the process. Perception is highly constructive- you create what you see based on utility and past learning. The idea of direct realism/direct perception is not well supported in the vision research world. The way that humans perceive the world is highly specific to our species and is NOT necessarily a true representation of reality as it truly is. Perceptual processes are heuristics for guiding behavior (i.e. finding food, avoiding death, mating, etc etc) See Interface Theory (D. Hoffman) , Vision ( D. Marr ) Hallucinogens alter the way information is dealt with on a higher level than the eye to begin with. Any differences in the experience would be rather muted, and would be analogous to the differences in bionic/biologic sight to begin with. A person with a bionic eye will get used to the input that it creates and that may be different from a natural eye (until bionic eyes become functionally identical). Taking hallucinogenic drugs will alter the way that perceptual items (objects, faces etc) are processed and created in the same way that it would alter them for people with normal eyes. tl;dr : Hallucinogens work on the brain, the mechanics of the eye shouldn't matter much.<\|im_end\|>
<\|im_start\|>user Does a language's complexity (grammar, pronunciation, vocabulary size, etc.) follow a standard curve over time? As a language develops, matures, and eventually fades away or morphs into new distinct languages, does it follow a standard pattern in terms of linguistic complexity? Is it true that mature languages simplify themselves over time, with rules for grammar, spelling, and pronunciation becoming more relaxed? If so, why do languages get complex in the first place?<\|im_end\|> <\|im_start\|>assistant There aren't "mature" and "immature" languages. As far as linguists are concerned, all languages (barring a few exceptions like creoles and some sign languages) are equally "mature". (Edit: to clarify this a bit, we have no idea how old most languages are. Excepting creoles and some sign languages, their origins are shrouded in the depths of human prehistory. We have the comparative method, and it's powerful, but it only gets us so far before it becomes incredibly unreliable.) As to whether languages get 'more' or 'less' complex over time, that's difficult to answer for a few reasons. There is no single measure of linguistic complexity. We can, perhaps, quantify complexity in a part of a language (for one such approach, see Ackerman and Malouf 2013), but not for a whole language. There are a lot of different pressures that act on language users. Speakers are generally lazy, and want to use the minimum of effort to get their point across. Listeners, on the other hand, want unambiguous and clear speech so they don't have to spend a lot of time processing the signal. One very popular (though controversial) framework these days is called Optimality Theory, and attempts to integrate these pressures into linguistic description.<\|im_end\|>
<\|im_start\|>user ELI5: How do we actually know what colours other animals can or can't see?<\|im_end\|> <\|im_start\|>assistant The rods and cones in your eyes contain dyes, which are the chemicals that do the light sensing. A dye is just a molecule that absorbs a very specific frequency of light. This makes them a particular color, and you can literally just measure the light reflected by these dyes to see what color they absorb. These molecules also bleach as they absorb light (which is how they adapt to brighter light), so you can also see what color light you have to shine on them to make them change color.<\|im_end\|>
<\|im_start\|>user [Fullmetal Alchemist] Why do the alchemists that we see in the series all practice just one type of alchemy? I'm sure it's in part due to them specializing in that type of alchemy -- a theory supported by the fact that state alchemists are required to present research in their chosen fields -- but is that all there is to it? If so, why don't more alchemists research and use the techniques used by, say, Mustang or Kimblee, considering how powerful they are? Is it all "just science," as Ed has said? Or does it ride off of Hohenheim's explanation that only a few people are able to draw upon the energy necessary for alchemy, and, as such, people are better attuned to different types? TL;DR: Alchemy: "Just science" or innate characteristics?<\|im_end\|> <\|im_start\|>assistant Throughout the series, alchemy takes a lot of study. It might be "just science" but most alchemists spend considerable time studying. State Alchemists are military. Just like the military has a standardized style of combat, the state alchemists learn a standardized method of fighting with alchemy. And just like there are many different martial arts of varying effectiveness, some alchemists work with special styles or methods. Like the Armstrongs who apparently pass their techniques down the family line. So yeah it's just science. Most of our scientists also get stuck doing routine work and research while a few rock stars stand out. So it is with state alchemists and their more talented peers.<\|im_end\|>
<\|im_start\|>user [Star Trek] Is everyone in starfleet entirely adverse to recording anything ever? So I've been looking through the records of a few missions (NCC-1701 and 1701-D) and I've noticed something; despite the fact that these ships are some of the most technically advanced pieces of equipment that the UFP has to offer, people aren't really ready for anything going wrong. For example, anytime there's a teleporter mishap everyone acts like this is the first time someone's been turned inside out or phase-shifted out of time or something; never once does someone call up the tech manual on a terminal and check out the F.A.Q.s or common errors. Also there doesn't seem to be much established procedure on temporal mishaps, if your ship gets displaced in time there's not much you're supposed to do other than reverse the polarity on something and cross your fingers hoping it gets fixed. It seems to me that these problems have to happen at least every so often, does nobody record the fixes to save people headaches and possible unwanted hyper-evolution?<\|im_end\|> <\|im_start\|>assistant Common problems are generally dealt with automatically by the ship. Most of the time when you're watching the highlight reel of Enterprise D missions, you're seeing them dealing with unprecedented issues like a giant space baby or a god-like trickster or trying to detect a cloaked Romulan fleet that's involved in a Klingon civil war.<\|im_end\|>
<\|im_start\|>user Was Aristotle an advocate for the welfare state? I heard this claim from Chomsky. He writes: "Aristotle also made the point that if you have, in a perfect democracy, a small number of very rich people and a large number of very poor people, the poor will use their democratic rights to take property away from the rich. Aristotle regarded that as unjust, and proposed two possible solutions: reducing poverty (which is what he recommended) or reducing democracy." However, I have recently read Aristoteles Politics. While it seems to me that he does advocate for a similar thing or rather hints at it, with his mixture of oligarchy and democracy, whoever, I seemed to have missed him advocating for wealth redistribution. Maybe I was just inattentive, because I found the text somewhat less interesting than Plato. Can someone help me out with a quote maybe? Thanks.<\|im_end\|> <\|im_start\|>assistant Take a look at Aristotle's comments in Book VII when he discusses ways of minimizing crime within the state as well as wars with neighbors. This book begins with a question about the equalization of property and the positions of Phaleas and Plato. What Aristotle is doing in this passage is both affirming Phaleas' general worry and then critiquing Phaeleas' application. He goes on to worry that Phaleas' process works best on small cities, but will create problems with larger ones. This is not the whole bit, but a part which goes directly to the point: > There are crimes of which the motive is want; and for these Phaleas expects to find a cure in the equalization of property, which will take away from a man the temptation to be a highwayman, because he is hungry or cold. But want is not the sole incentive to crime; men also wish to enjoy themselves and not to be in a state of desire- they wish to cure some desire, going beyond the necessities of life, which preys upon them; nay, this is not the only reason- they may desire superfluities in order to enjoy pleasures unaccompanied with pain, and therefore they commit crimes. > Now what is the cure of these three disorders? Of the first, moderate possessions and occupation; of the second, habits of temperance; as to the third, if any desire pleasures which depend on themselves, they will find the satisfaction of their desires nowhere but in philosophy; for all other pleasures we are dependent on others. The fact is that the greatest crimes are caused by excess and not by necessity. Men do not become tyrants in order that they may not suffer cold; and hence great is the honor bestowed, not on him who kills a thief, but on him who kills a tyrant. Thus we see that the institutions of Phaleas avail only against petty crimes. > The equalization of property is one of the things that tend to prevent the citizens from quarrelling. Not that the gain in this direction is very great. For the nobles will be dissatisfied because they think themselves worthy of more than an equal share of honors; and this is often found to be a cause of sedition and revolution. And the avarice of mankind is insatiable; at one time two obols was pay enough; but now, when this sum has become customary, men always want more and more without end; for it is of the nature of desire not to be satisfied, and most men live only for the gratification of it. The beginning of reform is not so much to equalize property as to train the nobler sort of natures not to desire more, and to prevent the lower from getting more; that is to say, they must be kept down, but not ill-treated. Besides, the equalization proposed by Phaleas is imperfect; for he only equalizes land, whereas a man may be rich also in slaves, and cattle, and money, and in the abundance of what are called his movables. Now either all these things must be equalized, or some limit must be imposed on them, or they must an be let alone. It would appear that Phaleas is legislating for a small city only, if, as he supposes, all the artisans are to be public slaves and not to form a supplementary part of the body of citizens. But if there is a law that artisans are to be public slaves, it should only apply to those engaged on public works, as at Epidamnus, or at Athens on the plan which Diophantus once introduced.<\|im_end\|>
<\|im_start\|>user ELI5: how does camera auto focus work?<\|im_end\|> <\|im_start\|>assistant There are a few systems, but the easiest to understand is contrast detection. This is very common on any digital camera showing a "live view" of what the sensor sees. The camera searches for parts of the image where color or brightness differ and adjusts the optics until the edges of colors and brightness get sharper. This is why if you try to focus on a featureless area, e.g. snow or a cloud, it will keep hunting as it's difficult to find any well-defined edges. Since all this requires is firmware (you need the image sensor already...), this is the cheapest. Other systems use specialized, dedicated sensors so the system can compute how unfocused the light hitting the sensors is, and predict how to move the optics; this is why the autofocus on a nice dSLR camera will be very fast. This is called phase detection.<\|im_end\|>
<\|im_start\|>user [General Sci-fi] If I was abducted by aliens and taken light years away from earth how could I find my way home if I gain control of the ship?<\|im_end\|> <\|im_start\|>assistant Assuming the aliens technology is understandable and user friendly you could simply see where they've been and back track. Otherwise you'll have to find a way to orient yourself by finding something like galactic north then figuring out which arm of the galaxy earth is on. Then narrowing your search to every star that's similar to ours. Which even if it takes an hour to visit a star you'd be searching for years possibly even decades. Hopefully you'd have the ability to detect faint radio waves from background radiation and then you would only need to get within around 50 light years of earth to pick up old SETI broadcasts and can triangulate earth's location from there.<\|im_end\|>
<\|im_start\|>user [The Big Bang Theory] Leonard's mother, being a successful psychiatrist should be aware of how damaging she can be to Leonard so is she doing what she does on purpose? I mean what the hell?<\|im_end\|> <\|im_start\|>assistant A lot of professionals struggle with blind spots in their analysis when the task is personal. Doctors are suggested to not diagnose themselves, even the best lawyers would never consider defending themselves in court, and plenty of psychiatrists have issues of their own. I mean they're human too. A lot of people assume that their kids are perfect angels even when there's tons of evidence to the contrary.<\|im_end\|>
<\|im_start\|>user After exercising do all proteins (meat, vegetable) have the same effect on muscle development?<\|im_end\|> <\|im_start\|>assistant Proteins are made up of "building blocks" which are called amino acids. Muscle repair/growth is limited by amino acid availability. To elaborate on that, the essential amino acid (essential AAs must come from the diet, whereas non-essential AAs can be synthesized by our tissues) which is least abundant sets the cap on muscle growth/repair. For example, if you had 10 units of each essential AA, but only 5 units of one of those essential AAs, you could only synthesize 5 units of protein, and all the excess AAs (5 units of each other essential AA) would be deaminated and burned for energy. Different proteins will provide amino acids in different ratios, so to answer your question, no, all proteins do not have the same effect on muscle development. This is why it's important to get protein from varied sources, and to seek sources that are known for having relatively complete amino acid profiles, such as eggs and milk.<\|im_end\|>
<\|im_start\|>user Can you study Computer Science without being super passionate about it? Atm I study philosophy at uni and due to some logic courses I took I remembered how I used to enjoy programming a few years ago in school and I wasn't too bad at it. Since then I've been thinking about switching to studying computer science. Like I said, I used to quite like programming and in general am interested in the topic as a whole but I am not someone who for example creates websites in their free time or does projects on their own and stuff like that. I feel like a lot of people who study cs are super passionate about it and know so much about computers (which I don't) and spend their free time programming. I'm not like that but still interested in cs, do you think it's a good idea if I still try? I'm also a bit insecure about switching to cs since I'm a girl and the subject is still widely male dominated at my uni (50 women and 250 men) and I don't want to fill out the stereotype of women not being able to do math or code. &#x200B; TL;DR: I loved the logic courses I did in philosophy and want to switch to cs but I'm not too tech-savvy or do coding projects for fun - is it a good idea if I still try? At school I was quite good at math and coding.<\|im_end\|> <\|im_start\|>assistant Software engineering != computer science. It really depends on how CS at your uni is taught. If it’s more theoretical and mathematically rigorous (this is the real CS you do in grad school) then it sounds like you are more likely to enjoy it than those who study it just to become software/web developers. If it’s more practical/industry-oriented then it doesn’t sound like an amazing fit for you. But to answer your question in the title: yes. CS is quite useful that even if you don’t feel super passionate about it at first you might grow to like it for practicality alone. But if you don’t care about projects and code development, why don’t you consider studying math instead?<\|im_end\|>
<\|im_start\|>user How can the liver break down so many different chemicals? The liver is where a lot of chemical compounds are broken down into useful or waste compounds. But how does the liver correctly handle so many different compounds? There are literally thousands and thousands of different compounds we can ingest, how do the liver cells know how to deal with each one correctly?<\|im_end\|> <\|im_start\|>assistant The liver has a lot of different enzymes and isoforms of those enzymes that takes care of most things we encounter in the world. All these enzymes systems are in homestasis with your body at any given time. That said, there's only about 12+ or so reactions that take place in a biochemical system and your plethora of liver enzymes and their isoforms can cover most anything you can run in to. Problems occur when a toxin irreversibly binds to a specific enzyme and the regular ligand can't bind. An example would be cyanide which binds and enzyme in the last step of making ATP, the energy your cells run on. Basically the body runs out of ATP and its ability to make more and you die. Another way you can die is if you overwhelm a particular enzyme system by taking too much of a substance. The liver is an amazing organ but we still need to take care of it. Avoid over doing on any substance, food or drug, including alcohol and you can live a full healthy life.<\|im_end\|>
<\|im_start\|>user ELI5: how can the dollar store sell items for only 1$ while the same items are much higher elsewhere? I always wondered if there is something wrong with those items? Maybe almost expired or damaged?<\|im_end\|> <\|im_start\|>assistant It's simple and yet not easy to understand. Take the entire stock of the dollar store and we find very few items valued $5-$10 and the majority at or around $1 price. Compare to other places inventory you will find that dollar stores inventory is a low dollar figure. This means that every space of rental property is cheap to stock and rotating inventory (assumed) along with smaller shelf space needed for these smaller items (assumed) allows greater selection. These stores rely on the consumer being able to afford more items more often, they reduce profit margins to increase customer volume. Or 7/11 has Twinkies for $1.29 with a profit of 35¢ and dollar store has Twinkies for $1 profit of 5¢. Dollar store sells five boxes of twelve each month 7/11 only two. $8.40 for 7/11 and $3.00 for the dollar store. Not great. But the dollar store customer buys 10-15 items and the 7/11 customer 2-5 items. Both models are successful by method, execution and market. They just see growth and profits different with either finding appeal in the eyes of different customers and business men alike.<\|im_end\|>
<\|im_start\|>user ELI5:Why is the newly-found SSL vulnerability referred to as "heartbleed" so dangerous?<\|im_end\|> <\|im_start\|>assistant SSL uses what's called "public key cryptography". Simply put, it means we have two different keys to protect the data. One of them is used to encrypt the data, and the other is used to decrypt the data. The one that's used to encrypt the data is public- anyone can see it. The one used to decrypt the data is private- it never leaves the server. When you connect to a website, it sends you some information from a certificate proving its identity (the certificate is signed by an organization your browser trusts) and it sends you the public key. Your computer then uses that key to create an encrypted message that only the server with this certificate can decrypt. This is important because information sent over the Internet is not sent over a dedicated line- there's lots of opportunities for people to intercept messages, which can include things like credit card information and passwords. This flaw allows an attacker to steal information from the server including that certificate. With that certificate, a malicious attacker can both impersonate the server and it can decrypt traffic intended for the server. And 2/3rds of the world's websites are vulnerable. Can you imagine the damage if someone used this flaw to impersonate Amazon and then stole the credit card numbers of everyone using Amazon? Or impersonated Google and stole everyone's Gmail passwords?<\|im_end\|>
<\|im_start\|>user ELI5: Why do people lose their accents when they sing?<\|im_end\|> <\|im_start\|>assistant A large part of accents is the pronunciations of various sounds, the stress patterns of words and the 'rhythm' of sentences. The last two are lost when singing, generally, because songs have their own stresses and rhythms that take precedence. The pronunciations of vowels and other stuff is kept in song, but the more noticeable things are generally lost.<\|im_end\|>
<\|im_start\|>user [MCU] How does Ant Man revert to his exact default size? Maybe I missed it somewhere in the movies, but is there a "default size button" or could Ant Man presumably be 107% or 97.3% his normal size?<\|im_end\|> <\|im_start\|>assistant Pym particles operate similar to atomic orbital tracks in that there are a set number of stable sizes. It takes the active application of the particles to flip you up and over the low stability sizes until you drop back into one of the stable positions. Your natural, normal height is the most stable track. Growing or shrinking you bounce along multiple stable points until you get to your desired height. That's why it looks like a series of different-sized ghost images when you observe it. The increments are larger than just a few percentage points plus or minus, so 107% would likely be a low-stability point and require active expenditure of Pym particles to maintain.<\|im_end\|>
<\|im_start\|>user ELI5: The Turkish Protests I know some will downvote me and refer me to r/answers, but I purposefully ask here in the hopes of getting as bare-bones an answer as possible (hence the sub). Haven't particularly kept up with Turkey goings-on in the past few years, but I always thought they seemed like a pretty secular nation...<\|im_end\|> <\|im_start\|>assistant To understand why the protests are happening, you need to understand some of the history of Turkey as a nation, and the Ottoman Empire before it. To understand the Ottoman Empire, you need to understand the Islamic concept of a caliphate. So, here goes: In the Islamic world, there has always been the concept of a "caliph," which in Arabic means "successor"– a successor to Muhammad. Sometimes, people think of a caliph like a "Muslim Pope," which isn't really accurate. The concept of a caliphate and a caliph isn't tied to any particular region. Instead, the idea is that the Caliph represents all Muslims, and has the authority to speak for them. In the most basic terms, it's a symbol of where power in the Islamic world rests at any given time. Here's where the Ottoman Empire comes in. As one of the most powerful states in the world for a few centuries, it was natural that the Caliphate was based in Constantinople, the capital of the Ottoman Empire, for most of that time. It's for this reason that the Ottoman Empire is often considered the fourth (and last) caliphate. Now comes Turkey. After World War I, the Ottoman Empire collapsed, and the war's victors were already circling like vultures, ready to pick apart Ottoman territory. However, there was a guy named Mustafa Kemal (or Ataturk, meaning father of all Turks)– he is basically the George Washington of Turkey, and it was with his leadership that Turkey managed to survive as a single state. Here's the catch: Ataturk also established a strong tradition of secularism in the Turkish state, and he abolished the caliphate. Ataturk had seen how a reliance on Islamic thought had stifled the technological advancement of the once-great Ottoman Empire. He felt that to adequately "westernize" Turkey, he had to do away with the state religion. This choice upset a lot of people, and still does. The current reigning party in Turkey comes from strongly Islamic roots, which also rubs people the wrong way– it seems to fly in the face of Ataturk's memory. Much of Turkish political history since then can be viewed as the struggle between Western secularism and the Islamic thought of the Ottomans. Given everything I've just told you, it should make a lot more sense why people got so mad about the bulldozing of a park to put up a replica Ottoman barracks– a symbol of Islamic military might. True, there was also a shopping mall, but ask any Turk, and they will tell you: the protests are about much more than a shopping mall. They are about the Turkish people's right to secularism, and about their right not to be swaddled in state-sponsored Islam. tl;dr: The Ottoman Empire was Islamic, Ataturk made sure that Turkey was definitely not. The conflict is about bulldozing a public park to put up an Ottoman barracks, a symbol with strong Islamic connotations. Also, shopping malls.<\|im_end\|>
<\|im_start\|>user ELI5: How do we know the universe is 14 billion years old? Do we have telescopes that can see that far? So, I understand we know the age because that's how long it took the light to reach us - but do we have telescopes that can see that far? If we invented modern Hubble telescope with better technology, wouldn't we be able to see farther than the current one, or am I sorely misinformed about how telescopes work?<\|im_end\|> <\|im_start\|>assistant The age of the universe is determined by measuring the rate at which its expanding. The light emitted by an expanding galaxy becomes redder as it moves away. This is called the red shift. The rate at which the colour changes determines its velocity. If this velocity was reversed and the galaxies move closer with the same rate of change, the time taken for them to come together to a dense point is measured as the known age of the universe.<\|im_end\|>
<\|im_start\|>user ELI5 How did scientists find out what layers exist under the Earth's crust? How did they determine that Earth has a solid core?<\|im_end\|> <\|im_start\|>assistant Most of this is figured out through seismic surveys. You make a loud sound somewhere and then measure how the sound waves travel through the Earth. This is exactly how ultrasonic surveys work in humans. The sound waves will experience different levels of refraction or even reflection as they hit layers where the density changes. We can measure this and figure out the density of all the rock. It turns out that the core of the Earth is very solid compared to the material above it. So similar to how sound bounces between the walls in a room but is muffled outside the room any loud sounds on Earth is bounced back from the core but is very muffled on the other side of the Earth.<\|im_end\|>
<\|im_start\|>user ELI5:What is happening when you see the air ripple on a hot day?<\|im_end\|> <\|im_start\|>assistant Light travels at different speeds through different mediums, and as the density of the mediums vary. The air is being heated at different rates between you and the horizon creating different air densities, like ripples on the surface of a river. Light from the horizon refracts as is passes through the different boundaries of densities, just like looking down into a river bed or sea shore through the water.<\|im_end\|>
<\|im_start\|>user ELI5: How does something gets contaminated from radiation? Re-watching Chernobyl and this doubt just got to me after seeing the cloths disposal of the first responder firefighters. As far as I know radiation works by collision with other's atoms and breaking them, so, how does something that has been affected by this collision become radioactive?<\|im_end\|> <\|im_start\|>assistant First off, radiation causes damage by breaking chemical bonds or by knocking electrons off of atoms in a way that causes unwanted chemical reactions, not (usually) by splitting other atoms apart. But there are two main ways: One is chemical contamination, where bits of the original radioactive material are mixed in with the other material. For example, small particles of dust containing radioactive metals could contaminate clothes worn at Chernobyl, or radioactive iodine could replace the normal iodine present in a human thyroid gland. The other is activation, where radiation itself turns an atom that was previously not radioactive into a new radioactive form. The most common form of this is neutron activation, where a neutron released by a splitting atom is absorbed by another nucleus, converting the other nucleus into an unable form. For example, non-radioactive Cobalt-59 might absorb a neutron and become the very radioactive Cobalt-60, so that a sample of cobalt near a neutron emitter can become radioactive even if none of the original radioactive material comes along with it.<\|im_end\|>
<\|im_start\|>user ELI5: How does your metabolism work? Like what makes you metabolism faster and what makes it slow down? In my day to day cycle what happens to it? How big of a factor is this in losing weight? Can I overcome a slow metabolism with exercise? Is it going to totally mess up a diet?<\|im_end\|> <\|im_start\|>assistant Metabolism is the balance between the amount of food you eat (what you put in) and the amount of energy you use from that food for things like moving, thinking, or growing (what comes out). So if you were a car, the engine would be what controls metabolism. As you hit the gas pedal, you turn more gasoline into the energy that moves the car forward. In return, the car loses gasoline and needs to be refilled, just like when you exercise all day you need to eat. And like a car, you can use up this energy at different rates. Sometimes this is out of your control: certain changes in your body at different times of the day will make you use more or less energy than you normally would (and some people naturally use more or less energy than others). For example, waking up into a cold house will force your body to shiver, thereby converting some energy into heat. Sometimes, however, the rate at which you use energy is in your control. You can change the amount of energy you use through exercise and drugs. Exercise, such as running or weight lifting, will use the energy in two different ways: first, you'll use energy to move fast or to lift heavy objects; second, you'll use that energy long after you've stopped exercising to build larger and more efficient organs, such as your muscles and your blood vessels. Drugs, such as testosterone, can trick your body into using more of that energy to grow your organs, but improper use of these may damage your health. On the other hand, certain drugs such as those that prevent seizures will trick your body into using less energy and may cause unintended weight gain. While you can't change your normal metabolic rate, you can take control of it by controlling how much you eat, what you eat, how much you exercise, and what drugs you take. Because your normal metabolic rate is unchangeable, it may be slightly more or less difficult for you to lose weight, but it is always possible.<\|im_end\|>
<\|im_start\|>user How do scientists measure the universe's expansion rate?<\|im_end\|> <\|im_start\|>assistant Red shift (similar to Doppler effect, but for light, which tells us how fast things are moving away from us) of standard candles (events that have consistent and known brightness (to measure distance) and colour (to measure red shift)). Usually done on the light curves of super Nova events.<\|im_end\|>
<\|im_start\|>user ELI5 the pros and cons of GMOs<\|im_end\|> <\|im_start\|>assistant Pro GMO foods: Crop yields can be improved by as much as 10x, allowing more people to be fed. Crop diseases can be wiped out, improving yields further. Anti GMO foods: Risk of the unknown. GMO's are man-made, and might have health or environmental risks that we can't predict or test for. Most GMO strains are produced and controlled by Monsanto, a company that many people hold a negative feeling. Risk of cross contamination, as GMO plants might grow and reproduce with ordinary farmers crops.<\|im_end\|>
<\|im_start\|>user How are we able to calculate the mass of the Sun? I understand that you use The Law of Universal Gravitation, but can someone give me an in-depth explanation?<\|im_end\|> <\|im_start\|>assistant Law of Universal Gravitation F = GM1M2/r^2 We know G, we know M2 (mass of earth), and we know r (earth-sun distance), so all we need to do is calculate F. We also know that for circular motion F = V^2/r r is the same as above, and V (velocity of earth) we can calculate based on the period of revolution (1 year) and the distance (2pir). Of course the orbit is slightly elliptical so you can get a bit more technical, but that should get you most of the way there.<\|im_end\|>
<\|im_start\|>user ELI5: How does a VPN change my location and IP address, even though I'm still going through my router?<\|im_end\|> <\|im_start\|>assistant A VPN will create a connection between two machines over the internet and send other traffic over that link where it is routed to the open internet on the other end. Think of it as a mail forward service. You can send an envelope within an envelope to your mail forward service and they will take off the outer envelope and send the inner one. When they receive a letter for you they will not open it but just stuff it in another envelope and put your real address on the front and send it to you. A VPN service works very similarly. Your ISP only see packets going between you and your VPN provider and all others only communicates with your VPN provider and don't know that they are sending all the traffic to you.<\|im_end\|>
<\|im_start\|>user Why are there more islands in the Pacific Ocean compared to the Atlantic Ocean? What causes this difference? The Pacific Ocean is significantly older than The Atlantic Ocean, does this have anything to do with the amount of islands each contains? Or does the depth of the oceans play a role in it?<\|im_end\|> <\|im_start\|>assistant There are several factors. Firstly, the pacific is obviously bigger so it's normal to expect more islands in it. Secondly, the Atlantic is growing (South America and Africa are moving away from each other) so the newly formed ocean bottom as this happens is at the bottom of the ocean. Some places in the Pacific are moving towards each other, hence places like Japan and New Zealand. When two plates push together it makes sense that parts of the ocean stick up above the water.<\|im_end\|>
<\|im_start\|>user ELI5: how does a painkiller like Percocet or Vicodin or tramadol work?<\|im_end\|> <\|im_start\|>assistant To first understand painkillers, you have to understand how pain works. Pain is a sensation, an electrical impulse sent from cell to cell to cell until it eventually reaches your brain and tells you "OW!" Each time the pain impulse passes through a cell, it has to cross the synapse, where it is converted into a chemical. This process is like hopping on a boat to cross a river; the impulse has to get off at a certain "dock" (receptors) which tells the next cell what to do with the signal. The next cell gets "pain" and the process repeats. Painkillers like Vicodin work by binding to certain receptors in the synapse called Opioid receptors. These receptors essentially tell a cell that receives a pain signal to stop transmitting it. The impulse basically dies at that cell and, because your brain never receives it, you don't experience pain. Painkillers like Morphine and Vicodin are highly dangerous, however, because of the side-effects they have on the body. Your body has a natural painkiller called endorphins that it pumps out whenever it experiences pain. When the body gets that job taken care of by an outside source (ie, morphine), it stops producing endorphins. That's why opiates have such bad withdrawal symptoms. Your body is constantly producing endorphins naturally, so we are always experiencing a level of pain constantly (think about the kind of impulses your feet is sending when there is 150+ pounds of flesh and bone crushing them). When these endorphins aren't produced, you'll be in terrible pain along with feeling all sorts of things your body naturally blocks out; chills, tingles, sweats, etc. Opiate withdrawal is not a fun experience.<\|im_end\|>
<\|im_start\|>user ELI5, Please: Why are people hollering for Obama to not raise Minimum Wage? I see a lot of flak from folks claiming min wage shouldnt be raised. However I see in min wage jobs, people, (myself included) who are not teenagers, and trying to raise a family, and how hard it is to do on mere minimum wage. What is it about raising minimum wage gets people so riled? Edit: Hey guys - I appreciate the time you took to explain this. Thank you very much for your responses :) <3<\|im_end\|> <\|im_start\|>assistant 1. Raise minimum wage 2. Raise prices (or lay people off) to compensate for increased labor costs 3. Cost of living goes up as a result 4. You're back where you started except now everything costs more. People earning (even slightly) above minimum wage won't see any pay increase and now effectively earn less. This means they also have less disposable income to dump back into the economy.<\|im_end\|>
<\|im_start\|>user CMV:Religion should not be a protected class in anti-discrimination laws (Talking about America and the west in general) Currently, if an employer is, beyond a reasonable doubt, proven to have fired/not hired someone for their sex, ethnicity or religion, that's deemed illegal. Let's ignore the fact that sexual orientation isn't on that list and focus on this. All of these traits share a common characteristic : They're innate and cannot be changed. A man cannot become a biological woman, a white person cannot become a black person, and (afaik) a gay person cannot become straight. Except for religion. I see no reason for religion to be treated similarly. I know a lot of people are born into religious beliefs, but there's no legal barrier preventing you from choosing not to believe in or practise a religion. I think an employer should have the right to fire someone for being Christian, like they would if they just didn't like their attitude. You wouldn't call someone bigoted for saying they generally are more likely to dislike republicans/democrats because they disagree with them, so why make that distinction for religion, when in the end it's all more or less an opinion? That being said, my research is shallow, this is mostly just mental gymnastics I thought up randomly.<\|im_end\|> <\|im_start\|>assistant >All of these traits share a common characteristic : They're innate and cannot be changed. Well because of the inclusion of religion, which is one of the first protected classes recognized by the United States government, this is not the common characteristic between them. The common characteristic is that these are all social classes that have been historically used to justify discrimination. Discrimination based on race, sex, ethnicity, disability, and of course religion is well-rooted in American history and society. To ignore religion on the basis of "you can change it" (which is not always the case since religion isn't simply tied to belief but is often tied to ethnic heritage and cultural traditions i.e. Judaism) is to overlook one of the greatest sources of discrimination in American culture.<\|im_end\|>
<\|im_start\|>user ELI5: Why do humans take so long to fully develop? Humans take over 20 years to grow and mentally develop completely, which is longer than most animals lives. Why does it take so long? What in nature causes this and has it always been this way for humans?<\|im_end\|> <\|im_start\|>assistant The body is ready for reproduction around 13-14 years (and in some populations even earlier than that). This isn't that much longer than many other large-ish mammals. It takes a long time for our brains to develop and learn properly (~18-25 years) because our brains are just so big and complex. And we have to go through a lot of cultural learning, with our culture being very complex because of language. No other animal has this.<\|im_end\|>
<\|im_start\|>user ELI5: How do astronomers identify galaxies that are light years away from us?<\|im_end\|> <\|im_start\|>assistant It depends what you mean by identify. If you mean "How do we tell that they are galaxies", we tell using telescopes that are big enough to make out tiny details. The size of the telescope and the color of the light you're looking at determine whether or not the galaxy looks like a dot or a blob or a galaxy; this is one of the reasons why we like to build bigger and bigger telescopes, to be able to make out smaller details. The other reason is that big telescopes can collect more light, so you can see dimmer things. Galaxies are really faint, because they're so far away! We can also tell that they're galaxies by looking at a spectrum of the light they emit. Galaxies don't look like anything else: they're stars and dust and black hole emission all added together. So even if it just looks like a dot, you can still tell if its a star or a galaxy because galaxies emit a different combination of colors than stars do. If you mean "How do we tell how far away they are", there are a few ways to do this. One is by using "standard candles". Basically there are some objects (certain types of supernovae and variable stars) in other galaxies that we know exactly how bright they are, and since brightness drops off with distance in a known way, we can measure the distance just by measuring how bright it looks to us. Another way is using redshift. The universe is expanding uniformly, so the farther away something is, the faster its moving away from us. This makes light "stretch out" as space stretches out, and when light stretches out it gets redder. So you can look at the light of the galaxy and compare it to other galaxies you know about, or chemical signatures from a lab, and determine how far away it is that way. This has some errors because galaxies also move pretty fast, so their actual motion can throw a wrench in that calculation, especially if the galaxy is close by so the redshift from the expansion of space isn't a huge effect. Lastly, if you mean "tell if its the same galaxy we saw before" i.e. how do we name galaxies; usually just by where they are on the sky. The sky has a coordinate system, and there are WAY too many galaxies to give them all a unique name (though some are named from previous conventions from early surveys). So we say "in this coordinate system, this galaxy is at this coordinates". Andromeda's name, in this context, is J00424433+4116074. Which is to say, we name galaxies by pointing to where they're at on the sky and saying "that one right there"<\|im_end\|>
<\|im_start\|>user Should I study Rand? Is Ayn Rand valuable as a philosopher at all? I doubt I will agree with her, but will I get anything genuine out of reading her or is she just entirely useless?<\|im_end\|> <\|im_start\|>assistant It can be used as good philosophical exercise. Read some of her short essays and spot how many unstated assumptions, logical fallacies, and misrepresentations of other philosophers you can find. And hey, you might just stumble across a decent point or two. edit: typo<\|im_end\|>
<\|im_start\|>user ELI5: Given the number and types of bacteria in our mouths, why is it that cuts/ulcers in our mouths don't get super infected very quickly? I've heard that the human bite is one of the most dangerous because of the types of bacteria in our mouths and teeth. Knowing this, wouldn't cuts to the inside of our mouths (tongue, cheek, inner lips, etc) also be very dangerous?<\|im_end\|> <\|im_start\|>assistant The bacteria we live with are well known and quickly recognized by our immune system, which is ready to kill them if they find themselves were they should not. It's always the same bacteria in your mouth so your blood has lots of antibodies ready.<\|im_end\|>
<\|im_start\|>user Say that atoms found in the island of stability were found to be really stable. What could we potentially use them for? There is something called the island of stability which dictates that it may exist heavy elements that are stable. If we create such elements and their half-time is on the order of years. What could we use this new material for?<\|im_end\|> <\|im_start\|>assistant Some things that we need heavy materials for could be improved if we had heavier materials. For instance, shielding against gamma radiation. You want something with a high Z so that it's got a lot of electrons which can leech energy from a gamma ray via the photoelectric effect and Compton scattering. Superheavy elements will have higher Z than anything else currently on the periodic table. They could also have some very cool chemical properties, because at such high Z, the atomic electrons have to fill higher and higher orbitals. This means that have larger and larger single-particle energy levels, and relativistic effects start to become important. This can actually change the behavior of macroscopic amounts of that material. The band structure can be completely changed by relativistic effects. You could have materials which you'd naively expect to be metals based on their location on the periodic table, which actually behave like semiconductors. Of course this is all theoretical, since we're talking about elements which might not have been produced at all, let alone in macroscopic quantities. But anyway, there are lots of reasons why we need to pursue this avenue of research and understand the extreme limits of nuclear and atomic physics.<\|im_end\|>
<\|im_start\|>user ELI5 why are some colours commonly found as surnames (white, brown, green) but not others (red, blue, yellow) And furthermore how does language play a part - I know red (rojas/rossi) is a Spanish and Italian surname but not English<\|im_end\|> <\|im_start\|>assistant Metallurgy. A lot of early surnames started with tradesmen and described their trades. Smith is the most common English last name because it is part of several professions: blacksmith (working with iron), whitesmith (working with tin), greensmith (working with lead or copper), and brownsmith (working with copper or brass). Most of these eventually were shortened to either their first or second half, leaving Smith as the most common surname, and Black, White, Green and Brown as relatively common ones. Edit: whitesmiths are tin<\|im_end\|>
<\|im_start\|>user CMV: If one were to create a new country today, there would be no reason to include an equivalent to the 2nd amendment in the new constitution By way of initial disclosure, I am Australian and hold the view that our gun control regulations are effective in reducing gun related violence. However, I am less interested in that issue (what gun control regulation should look like) than the relative legal importance of the 2nd amendment to Americans. It seems to me that Americans and the rest of the world approach the question of regulation from diametrically opposed positions. Americans seem uniquely pre-disposed to viewing gun ownership (in a broad sense) as a 'right', as necessary to a free society as free and transparent elections, freedom of speech, and other fundamental democratic norms. If one were to draft a constitution today (in a modern, developed country), not from scratch but as your founding fathers did, based on historical experience and examples from other countries, there would be no good reason to include an equivalent to the 2nd amendment instead leaving the question of gun ownership rights and regulations to the discretion of parliament/congress. NB: I have considered what I expect to be the counter argument; that tyranny may follow in the absence of armed resistance to which my initial response is (1) modern governments are unlikely to be overthrown by force, as distinct from mass political uprisings (especially where democratic institutions are already in place) or civil war and (2) the argument that gun control will not stop the flow of illegal weapons seems to cut both ways here - an absence of constitutional protection for guns will not make them impossible to acquire at scale. CMV. _____ > This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please *[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules). If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* *[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)*! Any questions or concerns? Feel free to *[message us](http://www.reddit.com/message/compose?to=/r/changemyview). Happy CMVing!*<\|im_end\|> <\|im_start\|>assistant Rights - freedom of speech, assembly, press, protection from torture, etc. are only as strong as the people who support them. Allowing a population to bear arms gives it some defense against a government that could infringe on any other rights. Not having that puts all the power in the government to give the rights it promises. Sometimes this is successful, but there are many examples of democratic governments turning authoritarian and quickly removing the rights of the people. Guns may not give the population an upper hand, but they help equal the playing field.<\|im_end\|>
<\|im_start\|>user ELI5: How come the extreme pressure at the ocean floor isn't making the water boil? (Like high pressure areas on land equals higher temperatures) I've heard the temperature underwater actually goes as low as 33°F<\|im_end\|> <\|im_start\|>assistant Forget about temperature for the first part. Water is made of molecules. Molecules in liquid water are relatively free to move, but they are still slightly attached to other molecules, so they don't "escape". When water becomes a gas, the molecules escape. If we increase pressure, we constrain the motion of these molecules. Water at higher pressure needs more temperature to boil, because we don't let the molecules escape freely. The second part, temperature. Pressure alone does not increase temperature. It's necessary to compress something (change its volume) to introduce energy (which, in part, increases temperature). Liquids have a hard time changing its volume, so it's very difficult to change their temperature by compressing them. Finally, water at the bottom of the ocean is cold not because of the pressure, but because cold water is denser than hot water, so it sinks. In equilibrium, water at the bottom is colder than water at the top. Edit: Remember, PV=nRT only works for ideal gases. Water is not an ideal gas, especially liquid water.<\|im_end\|>
<\|im_start\|>user Do atoms emit spectral lines in the nonvisible spectrum? I'm taking a Stellar Astronomy course, and have a very limited understanding of spectroscopy. My basic understanding is that emission lines are the result of electrons needing a very specific amount of energy before they can change orbitals, and when changing orbitals they emit a photon to account for the energy change. This photon results in the emission line, right? Assuming I have that understood properly, Here is my question. Do atoms have emission/absorption lines in the radio/infrared/ultraviolet etc. spectra? And if so, could we gain any information by examining these additional spectra? Like I said, My understanding is very limited, but I really enjoy this subject and look forward to the answer!<\|im_end\|> <\|im_start\|>assistant Electronic transitions commonly occur in the UV and visible region. Most materials that aren't colored (i.e. do not absorb visible light) do in fact absorb in the UV region somewhere. There are other types of transitions that occur in the radio, microwave and IR region, but these are not generally electronic. They include spin magnetic moment, vibrational and rotational transitions.<\|im_end\|>
<\|im_start\|>user What's the probability that in n vectors, each with n elements where each element is a random integer, that the set is linearly independent?<\|im_end\|> <\|im_start\|>assistant You are asking the question: "Given an N x N matrix A with random entries from some commutative ring R (e.g., integers), what is the probability that A has non-zero determinant?" The word "random" in this particular context means that we have assigned some probability distribution to the ring R and the matrix entries are chosen according to that distribution. (In particular, there is no uniform distribution on the integers, so your question doesn't make sense as stated since an unqualified "random" is usually taken to mean "uniform".) This question is pretty tough and there are entire branches of mathematics that describe random matrixes. One easy-ish result is the following. Suppose the ring R is just the real numbers. The condition that the matrix A has zero determinant is equivalent to some equation of the form p(a_ij_) = 0, where p is some polynomial and the a_ij_ are the entries of the matrix. This equation describes some set in R^(N^2). All non-zero polynomials on R^(m) are non-zero (Lebesgue) almost everywhere, whence the set of points that satisfies p(a_ij_) = 0 has Lebesgue measure zero. Now suppose we give the real numbers any probability measure. That measure is absolutely continuous with respect to Lebesgue measure, and so the zero set of p has zero probability. In other words, the probability that a random matrix is singular is zero, no matter what the probability distribution on the reals is. For other rings, the answer may be different. For instance, if R = Z_2_ and we give R the uniform distribution, the probability that A is singular is actually positive for all N. (In fact, the probability remains positive as N --> infinity.)<\|im_end\|>
<\|im_start\|>user ELI5: Can you explain how online data works and why the corporations want it?<\|im_end\|> <\|im_start\|>assistant Personal data is anything having to do with you or your interests. What colors you like, what you eat, where you work, how you look, etc etc etc. Corporations use this data to automatically target ads, which lets them stop using money on ads which don’t have any chance of success. The downside is with all that personal information, they or hackers who get access could work out things in your life and blackmail you.<\|im_end\|>
<\|im_start\|>user ELI5: How exactly does counting cards work and how does it level the playing field against a casino or improve one's chance of winning?<\|im_end\|> <\|im_start\|>assistant Counting Cards is all about keeping track of probability. Let's say you're playing blackjack. And the first five cards that are dealt are relatively low (let's say less than seven). If you keep track of this, you know that the probability of drawing a high card is larger than normal because several low cards have already been played. This information will help you decided whether or not it's smart to hit or pass.<\|im_end\|>
<\|im_start\|>user Why do tidal ranges in different parts of the world vary so greatly? I understand the basics of how tides work with the sun and moon causing neap and spring tides, but why does the tidal range vary so greatly in different areas? (from as little as 1m to 17m)<\|im_end\|> <\|im_start\|>assistant Resonance based on shape and depth of the basins. Tides are essentially very large waves which travel around an ocean basin. Unlike the waves you normally see at the beach which have a wavelength of 1-10 meters, the tidal wavelengths are 1000s of km. For a place with large tides, such as the Bay of Fundy, the natural unforced period for a wave to travel around the basin is very close to the period of the gravitational forcing of the sun/moon (~12 and ~24 hrs). Therefore the sun/moon are very effective at driving a large tidal response. Other basins, such as the Mediterranean, have a natural free wave frequency which is different from the sun/moon forcing and thus ineffective at transferring much energy into tidal motions. In order to get large tides, the size and depth of the basin have to be in the sweet spot for resonant excitation. You can create a similar resonant wave in your bathtub. If you swish your hands back and forth you can create a standing wave where the water sloshes back and forth from end to end. The period of this wave depends on the size of your tub and the water depth. If your hands move back-and-forth at just the right frequency, you can excite a large sloshing with very little effort. But if you move your hands too fast or too slow, you will still create lots of small waves and ripples, but it's only when you force at the resonance frequency that you can create the really large response.<\|im_end\|>
<\|im_start\|>user [LI5] Can someone explain software patents (and the controversy surrounding them) please? Inspired by [this](http://www.reddit.com/r/reddit.com/comments/j44gp/software_patents_in_the_real_world/). I'm specifically looking for information about why they are so controversial, and what they mean for software developers looking to market their own prouduct (e.g. if someone makes a spreadsheet application can Microsoft sue them for copying Excel)? Edit: Thanks all. Great explanations.<\|im_end\|> <\|im_start\|>assistant Patents primarily help inventors get an advantage over others who only copy things. This way, if companies want to use an invention from other companies, they have to pay money to the inventor otherwise the inventor can file a court case against the company that copies. Companies that copy are allowed to legally copy the invention only after a number of years have passed since the invention was first 'patented'. With software patents, there are two issues - First is the speed with which inventions/updates happen. Unlike other areas where patents make sense, software require lesser time to develop. As a result, the rate at which new updates happen is very very fast. Just because Microsoft built a way for users to manage spreadsheets on a computer, it does not mean other competitors should stay away for 10 years or so before they can launch a similar service. 10-15 years is a very long time in technology. Even a year is. Second and the more important one is the number of useless patents that companies file as a way to harass competitors. An example is the patent that Apple filed to prevent competitors from using the 'swipe to unlock' feature on the iPhone. Quite clearly, this is just a creative way to unlock phone and there is nothing technologically brilliant about it that it needs a patent. Still, companies do such silly things and that is causing the controversy.<\|im_end\|>

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