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ELI5: What is bitterness, really? | I've looked through tons of ELI5 questions on bitterness and the majority seem to accept "bitterness" as this abstract concept that simply exists, like if you were trying to explain what wind looks like. As a cook and bartender, I enjoy bitter foods daily - amari, bitter veggies, grapefruit, lemon pith, coffee. I can go on and on. I know what it tastes and feels like.
But what is it, on a chemical level? Why do so many poisonous or even unnutritious things taste bitter? How do our taste buds pick it up and what is the "bitter" signal sent to our brains? Why is it neutralized to a degree by other specific flavors?
For an alternative and extended answer to this question, can you extrapolate on this? If humans publicly and consistently accepted and appreciated bitterness in foods, would we continue to have a nature-based aversion to bitter foods, or would it be seen as a generally desirable characteristic? Sugar and salt are the most obviously sought after, but appreciation for acidity is becoming more and more common and I wonder about the effect of marketing and publicity as a means for changing perceptions of flavor.
**In short, is perception of bitterness as a negative (less desirable) flavor largely or even completely driven by environmental influence?** | Bitterness is perceived via an assortment of taste receptor proteins, the TAS2R family. It's hard to predict from the structure alone which substances activate those receptors, but generally a lot of secondary plant metabolites do, and a lot of those are a defense system by the plants and thus toxic. At the core, it's an avoidance mechanism to prevent you from eating stuff you shouldn't eat.
You'll notice that kids don't like bitter stuff, not at all. They are even more sensitive to it, which plays into their dislike for certain vegetables. However, we humans being smart, we figured out that there is bitter stuff we can eat safely and came to like it - but that is pretty much always an acquired taste, learned behaviour overriding the innate preferences. | 34 | 22 |
What qualities of quantum fields account for their differences? | My understanding of quantum field theory is that all particles are now seen to be disturbances in a field - the electron field, the electromagnetic field (photon), the gluon field, and so on. To me this sounds like saying that everything is made of one *kind* of stuff: a field. But the way these fields behave seem very different: one is influenced by massive bodies, one is influenced by charged particles, disturbances in one produces one kind of particle, another produces a very different kind of particle. But isn't a "field" just a number assigned to every point in space? What qualities do fields have that produce such different behaviors? How can a field be said to be different than another field, other than its strength at a given point in space? | Each field has different properties than the others. For example, different spins. The photon field is a vector field, the Higgs field is a scalar field, the electron field is a spinor field, the graviton field is a tensor field, etc.
So at the very least, particles with different spins/parities cannot be said to come from a single field.
Then each kind of particle has its own mass, and its own couplings to the various other fields. It wouldn't really make sense to say that these are all the same field, at least not without altering the formalism in some way. | 18 | 25 |
eli5 : How did we measure the distance between the sun and the earth? | You have to start before that. The first distance to be measured with any accuracy was that of the Moon. In the middle of the 2nd century BCE, Greek astronomer Hipparchus pioneered the use of a method known as parallax. The idea of parallax is simple: when objects are observed from two different angles, closer objects appear to shift more than do farther ones. You can demonstrate this easily for yourself by holding a finger at arm's length and closing one eye and then the other. Notice how your finger moves more than things in the background? That's parallax! By observing the Moon from two cities a known distance apart, Hipparchus used a little geometry to compute its distance to within 7% of today's modern value.
With the distance to the Moon known, the stage was set for another Greek astronomer, Aristarchus, to take the first stab at determining the Earth's distance from the Sun. Aristarchus realized that when the Moon was exactly half illuminated, it formed a right triangle with the Earth and the Sun. Now knowing the distance between the Earth and the Moon, all he needed was the angle between the Moon and Sun at this moment to compute the distance of the Sun itself. Aristarchus estimated this angle to be 87 degrees, not terribly far from the true value of 89.83 degrees. But when the distances involved are enormous, small errors can be quickly magnified. His result was off by a factor of more than a thousand.
Over the next two thousand years, better observations applied to Aristarchus' method would bring us within 3 or 4 times the true value. There was still only one method of directly measuring distance and that was parallax. But, finding the parallax of the Sun was far more challenging than that of the Moon. After all, the Sun is essentially featureless and its incredible brightness obliterates any view we might have of the stars that lurk behind.
Enter planetary relational distance and the key is the transit of Venus. Johannes Kepler and Isaac Newton had shown that the distances between the planets were all related; find one and you would know them all. During a transit, the planet crosses in front of the Sun as seen from Earth. From different locations, Venus will appear to cross larger or smaller parts of the Sun. Kind of like a planetary eclipse. By timing how long these crossings take, James Gregory and Edmond Halley (the comet guy) realized that the distance to Venus (and hence the Sun) could be determined.
This presented a small problem though. Venus is only in transit once a generation (though often come in pairs). By the time Halley realized that this method would work, he knew that he was too old to have a chance to complete it himself. So, in hope that a future generation would undertake the task, he wrote out specific instructions on how the observations must be carried out. In order for the end result to have the desired accuracy, the timing of the transit needed to be measured down to the second. In order to have a large separation in distance, the observing sites would need to be located at the far reaches of the Earth. And, in order to ensure that cloudy weather didn't ruin the chance of success, observers would be needed at locations all over the globe.
Despite these challenges, astronomers in France and England resolved that they would collect the necessary data during the 1761 transit. Although not all observers were successful (clouds blocked some, warships others), when combined with data collected during another transit eight years later, the undertaking had been a success. French astronomer Jerome Lalande collected all the data and computed the first fairly accurate distance to the Sun: 153 million kilometers, good to within three percent of the true value!
By the way, the number we're talking about here is called the Earth's semi-major axis, meaning that it's the average distance between the Earth and the Sun. Because the Earth's orbit isn't perfectly round, we actually get about 3% closer and farther throughout the course of a year. Also, like many numbers in modern science, the formal definition of the astronomical unit has been altered a bit. As of 2012, 1 AU = 149,597,870,700 meters exactly, regardless of whether we find the Earth's semi-major axis is slightly different in the future.
Tl;dr: Bunch of guys, over a period of two thousand years, armed with a bit of creative ingenuity and a celestial phenomenon, used high school level trigonometry to figure it out. | 1,769 | 787 |
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ELI5: if they all come from milk, why do cheese, butter, cream and yoghurt all have different nutritional benefits/impacts? | For instance, a bowl of yoghurt is good for me but a bowl of cream isn't? Please explain! | Besides the fact that different parts of the milk - which have different ratios of fat to protein to water - are used for different products, many dairy products rely on bacterial or fungal action. These microbes digest some parts of the milk into new compounds, and change the overall nutritional profile. | 60 | 73 |
ELI5: When filling out an address form online, why do websites ask for City and State, before Zip Code, when the Zip Code could be used to autofill the other information? | 1. Design decision, people are more used to address being address/street, city, state, zip to the point that it's an automatic reflex to enter things that way
2. It's extra work to maintain a database of zip codes and cities or tie into an API that provides this service | 12 | 23 |
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ELI5: What determines the location of a headache? | Pain management doctor here,
There are many, many sources and causes of headaches. The location and type of symptoms are the main things we look for in coming up with a diagnosis. For example, migraines are typically one-sided and throbbing while hemicrania headaches involve one side but are more continuous. Cervicogenic(meaning, from the neck) headaches typically involve the back of the head. Tension headaches typically feel like a band across the head. Cluster headaches involve very intense pain behind an eye. There are many other types, as well.
Going into the actual mechanism behind all of these is a huge topic and not fully understood -- but each of them has very different pathologies, prognosis, and treat treatment. | 3,748 | 5,613 |
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If the speed of light is a constant independent of the speed of the observer - why does the doppler shift occur? | Is it that the light isn't slowed down or speed up, just that the wave itself becomes stretched or compacted yet propogates at the same speed?
EDIT: Sorry I am not sure how to add the appropriate science tag - but I think it is a wonderful idea! Keep up the great work mods! | The Doppler shift occurs with light because regardless of the speed of light, it is still a wave.
Changing your reference frame causes you to perceive the 'peaks' and 'troughs' of the wave at a different rate. Consider driving a boat over ocean waves. If you drive towards or away from the direction of the waves, you can alter their perceived frequency.
This is true of any wave. | 12 | 23 |
ELI5: How are graphics cards improved every year? How can you improve a product so consistently? | What exactly goes on to improve a card? | The most important factor is the manufacturing process. It's called "photolit*h*ography"- which means "writing *in stone* with light" (edit: Thanks for the correction). Basically, they're using a fancy Xerox to print electronic circuits onto a slice of silicon.
Over the years, they have found ways to print circuits in finer details, which allows them to cram more stuff onto a piece of silicon. So they're improving the shape of the individual transistors to work better in small sizes and they're also using light with smaller wavelength, which is basically like getting a smaller brush size. In the past few years, they have started to work with a technology called "EUV", that is extreme-ultra-violet. Its "brush size" is 30 times smaller than the UV-light that causes tan and skin cancer. This is extremely difficult and expensive to work with, but it allows to cram billions of transistors onto a single chip: NVidias top chip, the GA100 used for their "Tesla" cards, has more than 50 billion transistors, compared to 20 billion on its predecessor that was made without EUV. | 1,059 | 1,479 |
ELI5: How is calculus different from algebra? | I've never really understood this but was kind of afraid to ask. What kinds of problems does calculus solve that makes it so special? | Calculus deals with calculations of quantities that are changing, these need special techniques not part of other branches of maths.
A simple example, you can use an algebraic formula to calculate the displacement of a moving mass subject to a constant force using f = m.a and s = u.t + a.t^2
However if your moving object is a rocket, expending fuel to provide the force, the mass, and therefore the acceleration, is changing constantly so simple formuli can't be used and you need calculus to do the same calculation.
Calculus also gives ways to calculate maxima and minima of mathematical formulae and much other useful maths.
edit for misspelling | 40 | 34 |
ELI5 : How come we can’t remove the extra chromosome that causes Down syndrome? | You can be born missing parts of a chromosome how come we can’t just recreate this process and remove the extra chromosome? | A person's DNA is stored independently in every cell of their body. It is thus impossible to execute any sweeping change after a person's cells have multiplied to the point where they are grown.
Even if you could, they are already grown, and so changing their DNA will not cause their body to magically rebuilt itself. | 36 | 15 |
ELI5: If glass is tightly packed atoms (solid), how can it be completely transparent? | Density of atoms doesn't necessarily relate to the opacity of a material.
Basically, any atom has a cloud of electrons, which has specific energy levels. When light hits these electrons, they can cause these electrons to change energy levels - this means they can absorb specific frequencies. This is called atomic absorption.
When you have bulk material, like in glass, you no longer have specific, discrete energy levels. Instead, energy levels combine to form _bands_, and the energy difference is called a _band gap_. Just like atomic absorption, only photons with enough energy to cross the band gap can be absorbed.
So the answer is that glass has a band gap in the UV range, so visible light passes through fairly easily. | 52 | 55 |
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ELI5: Why is college so expensive, and where exactly does that money go? | BEFORE YOU SAY REPOST: I searched for this, and read a few threads, but I'm really confused how a college can charge thousands of dollars, and have professors who make $60,000+ a year, and there is enough kids in that class to pay for more than just one professor's income for the WHOLE YEAR. And after they put people in debt, where does the money go? What does a college do with all the extra money? Now I know there's general campus upkeep, and that takes a chunk out of the money. The way people put it college takes so much money from all the students, and I just don't understand where all that money goes, or why taking that much money is really necessary.
EDIT: Read all your replies, thanks for helping me understand. Quick side note though, is really no one trying to figure out a better way to pay for college? So many people get in crushing debt because of it, there has to be a better way. | There are two things going on in your question.
1. Why does college cost a lot (for whom? Compared to what?)
2. What do colleges to with their revenues?
The second question is the easiest to answer, if only because university budgets are generally public record:
1. Salaries and Benefits for Faculty, Staff and Administration
2. Facilities/Maintenance Upkeep
6. Tuition assistance (revenues used to support low-income students and merit based scholarships)
3. Subsidies for Athletic Departments (there are, IIRC, only 4-6 schools in the entire country that have athletic departments that turn a net profit - all the others require that money raised by the university be paid into the athletic department for it to run)
4. Information Technology (Universities demand a lot of computer resources and associated technologies, eg wireless networks, servers, internet connections, wired networks)
4. Campus Health and Safety (police, fire, environmental controls)
4. Student Services (Health care on campus, etc)
4. Utilities (campuses use a lot of electricity, water, sewer, etc)
5. Marketing (to promote attendance and the university and raise the profile of its graduates)
6. Legal Services (all universities have lawyers on staff who make healthy salaries)
7. Debt Service (Universities borrow a lot of money to build buildings, and then have to pay interest on the debt)
8. Other "business type" expenses (travel for senior administrators, office supplies, etc)
When you say "so expensive" that comparison has to be informed by something. What are you comparing the cost of college to?
It's unquestionable that the overall cost, inflation adjusted, for college has grown substantially. Most of these increases can be attributed to the advances of technology and science. Fifty years ago, the expensive tools used to educate and do research didn't exist - so it wasn't a question of them getting to be more expensive, it was a question of them being available or not. If supercomputers had existed 50 years ago, you can bet every university would have one in some form - meaning their costs would have been higher.
What has changed a lot is that the number of people going to college is much, much, *much* larger than it was. And the amount of public subsidy given for each student is much, much lower.
So when you say, "the cost of college has gone up" - you have to consider two factors. The *overall* cost of operating a college has gone up, but the same college today has 40,000 students - where 30 years ago it had 5,000.
The *cost* of educating those students actually hasn't changed dramatically on a *per student basis* - we are just educating more people than we used to. What has changed is that governments used to subsidize upwards of 90% of the cost of education. Today it's less than 30%. That difference shows up in tuition - making the cost *to the student* much, much higher. | 30 | 50 |
CMV: Learning a programming language should NOT be seen as equivalent to learning a foreign language | For background, I speak three languages and am comfortable in four programming languages.
I've seen it argued that programming language courses should be valid options for "learn a language" requirements at both the high school and college levels. This is grossly inappropriate and does not get at the point of learning a foreign language nor the point of learning a programming language.
Learning a programming language is really about **learning how to dissect a problem and give followable instructions for solving it**. The vocabulary is tiny, the grammar is simple. The complexity comes from various ways to break down the problem into tiny steps.
Learning a foreign language is about **learning how to understand and express oneself to someone who does not speak your language**. Vocabulary and grammar are far more complex. The "problems", as they are, are not nearly as complex as in programming. In addition, learning a foreign language usually requires a person to learn about another region of the world and the culture of the people who live there; computers do not have cultures.
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> *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!* | Learning programing is seen as beneficial as learning another language. That does not preclude them from their differences. In fact, one being simpler and yet being equally beneficial should give more incentive to learn that one. You state that programing language is simplistic, yet so is learning french for a native spanish speaker. The simplicity is relative, and is almost entirely dependent on how one's temporal lobe works. | 862 | 4,445 |
CMV: Not everyone should strive to be a college graduate and we shouldn't penalize them for it | I have a friend who is very dyslexic. He's amazing at fixing things and can make anything out of anything. He went to college and wasted a year and a half struggling to achieve something he wasn't passionate about. He dropped out and found his niche in Oregon on a farm. I think college is a noble pursuit and so useful for expanding views on life, and how the world works. However, I don't think everyone benefits from college, and I don't think everyone should aspire to be a college graduate. There are certain professions that absolutely require it, but for those that don't why is it so essential? Some people can't advance in their careers because they never attended college. Isn't the experience you gain in a field more valuable that having a generic degree where most of the classes may not directly pertain to the profession you're currently in?
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[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)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Up to what point is education necessary? If you don't need to go to college, do you really need to attend high school? What about elementary school? If you think a certain level of education is important, why did you settle on that point? Does a farmer who only does manual labor need to know how to read?
On the flip side, what position can't be enhanced by further education? There are farmers who pick berries while working for someone else. There are farmers who run their farms like a small business. There are farmers who own gigantic robotic milking and harvesting machines. All of these types of people are farmers, but they all have very different levels of education and success.
The goal of education is to shift as many people away from menial labor and into robust, highly efficient fields. If you don't take the time to become the most efficient farmer you can be, you are going to be outcompeted by those who do. Hard work is important, but it needs to be directed in a way that makes a real impact. A person who pushes a rock up a hill over and over does plenty of hard work, but accomplishes nothing.
Perhaps not everyone has the capacity to be a successful college graduate. But that doesn't mean they shouldn't try. People should keep pushing until life puts them down and they can't advance any farther. They shouldn't limit themselves without even trying. A marathon runner who passes out after only 5 miles still accomplished much more than a person who never got off the couch. | 14 | 57 |
I've heard a few knowledgeable people say that formal education isn't really necessary to be hired as a programmer, so how would one of these people know when they are hirable? | My background: I code on and off for my math hobby, and have worked on personal projects in Python, JS, Haskell, and various scripting languages for miscelueanous things. I've never made anything with a UI, but I'm fairly proud of the complexity of some of the algorithms I've been able to create and implement. I've never had my code reviewed but tend to make it look nice and enjoy writing comments.
Anyways, I was wondering what people look for when hiring. I'm sure the fact that I've never truly used GIT before is a problem, and the fact I have little experience optimizing. Also when I work for myself I can afford to get stuck for long periods of time and spend days googling; I know that's a big meme but how acceptable is that really? How important is optimizing?
TLDR: I'm just not sure what separates a hobby coder from a hirable one. | Fundamentally, a job in software development is writing code to solve a companies problems. Because of this, the number one skill you will need to demonstrate to get an entry level position is the ability to produce solutions to problems.
In technical interviews this will come in the form of: here is a problem - write a solution.
In non-technical interviews this will come in the form of an interviewer asking you in depth questions about one or more of the projects you have listed on a resume. They will try to figure out the scope of a problem involved in your work and how you solved it.
Interviewers will consider other skills; programming languages, familiarity with version control (git / svn / whatever), frameworks that they use on the job, code samples (and how well they are documented), and so on, but these will all come second to the fundamental question of "can this person solve problems".
As to whether you are ready or not: can you convince an interviewer that you can solve interesting problems? If you can then finding a job will come naturally. | 16 | 22 |
How do investment bankers and other financial careers produce wealth/value? | A popular opinion seems to be that people in finance produce little value and/or are just parasites. This seems to rely on the assumption that wealth is a zero sum game.
Are there good examples of how these people increase production?
| Starting from the obvious:
Businesses require capital - startup money to buy property, plant, equipment, or whatever else. Good businesses are a better allocation of capital than bad businesses. Therefore, we want smart venture capitalists and angel investors to go over new business plans, and to try to distinguish the good entrepreneurs from the bad ones.
The benefits these guys provide are obvious. Entrepreneurs come up with ideas and venture capitalists help vet them. So what about the rest of the financial markets?
Well, the venture capitalists need to be able to exit the market, so they can invest their money in new startups. So you need some people to turn a new company's ownership into publicly traded stock. Then the venture capitalists can exit (sell).
Here's where the rest of the finance people come in. Stock prices, from beginning to end, *must* reflect the fundamentals of the underlying company.
Suppose that the stock traders weren't doing their job right, and they were overvaluing, say, all of the tech stocks. Well, then you'd see the venture capitalists giving too much money to dubious tech startups. Who cares if the thing is profitable in ten years? If we can sell the stock immediately at a high price, that's all we care about!
This isn't a hypothetical; this is *exactly* what happened in the late 1990s. Capital was poured into dubious tech companies when it should have been going into other, more useful projects. If we had smarter finance professionals who didn't overvalue the tech stocks, then we'd all have been better off. | 23 | 28 |
[ELI5] Why are there so many sorting algorithms? | I'm watching these videos on YouTube of sorting algorithms sorting 200 bars by height, and I'm absolutely bewitched.
But what's the difference? I see that there are two important pieces of information: comparisons and array accesses. Some sort the data with more comparisons than array accesses, some will do it the other way around. Some will have only a few thousand of each, others will make tens of millions of comparisons.
I can also see that there are different ways to sort. Some are very careful and methodical, some start out kinda fuzzy and get more precise with the sorting as it goes on. Others sort into chunks and then sort those chunks together. One of them seemed to hold on to a chunk of values and move it around as it sorted the rest of the data. | The main difference is efficiency in two categories time and space (how fast it is and how much memory it needs).
BUT there are way less algorithms in daily use as there are in some videos or wikipedia.
You can compare it roughly with how to tie shoelaces. There are many ways to tie. Some are for beginners, some are very fast (take a look at youtube), but most of the time you make your normal tie and it fits your needs. | 29 | 19 |
Experts say 70% of a population needs immunity to reach the herd threshold. Where I live, in Texas, polls say 1/3 of people refuse to get the vaccination. Can we reach herd immunity? | Considering that children are not currently being vaccinated, and studies are showing that immunity is stronger and lasts longer through the vaccine as opposed to infection, how likely is it that we'll actually reach the point people are calling "back to normal"? | Natural immunity will work to fill in the gaps. We don't know how long it lasts, but seems to be a while.
Also, keep in mind that the biggest issue with COVID-19 is how quickly it overwhelms medical facilities. Even if the virus is not wiped out, if the most vulnerable and a good chunk of the population are protected, it will become just another deadly virus we live with like the flu. | 231 | 608 |
CMV: Online "slacktivism" is actually a more effective way of changing people's minds than protesting in the streets. |
I am speaking from experience here. I've been to some protests, the March for Science for example. I would characterize it as "preaching to the choir". Everyone who was there already agreed with me. Hardly anyone who wasn't involved with the march was actually interested. Most people who passed by probably didn't even read the hilarious one sentence long signs that people made. The only people who were there who maybe didn't agree were the police, and they just seemed mostly annoyed that they had to block traffic and corral protesters.
Now if I start a debate online, on facebook or reddit for example, I won't be limited to what can be crammed onto a piece of cardboard. I cant type lots of sentences. People who disagree with my will come and see what I said. Sometimes they write a rebuttal, then I counter that rebuttal, then still more people come and see that conversation, sometimes thousands more people. And every once in awhile, I actually change somebody's mind. It is about 1000 times more efficient than traditional protesting. If you disagree then change my view.
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> *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!* | It may be the case that when raising awareness there’s a tremendous value in being disruptive. You seem to think otherwise, but it’s far easier to ignore someone online — if you disagree with them, chances are you aren’t on the same website or similar news feed in the first place. Websites gather like-minded people together. It’s much harder to disregard thousands of people marching through the streets, and having them be physically present signals a level of commitment and reality that is just not possible through text communication alone. | 11 | 15 |
CMV: corporations should be required to pay for the disposal of their products. | If companies were explicitly responsible for the disposal costs associated with their products it would incentivize the production of items that are more reusable and less costly to dispose of. It would also help ensure products are correctly disposed of, since there would be dedicated funds.
The current system unfairly shifts the blame the the consumer, is much less effective. The debate about plastic straws is a great example. It puts extra pressure on people with disabilities, addresses such a small part of the problem of plastic waste, and has turned into a status symbol in many ways.
Yes, this would increase the cost to consumers, but consumers already pay this cost indirectly through taxes and degraded resources.
Edit: logistically, I'm thinking something similar to the the carbon cap and trade market. Disposal cost would be set aside at the beginning of the product's life, regardless of when our where it gets disposed of.
I'm not saying you should mail your garbage back to whoever you bought it from. That's dumb. The money might not even go directly to disposal of that type of product, but pubic public outreach, or research, or clean up. | If you want to use cost to incentivize the correct disposal of waste (I good idea IMHO) shouldn’t that cost be applied to the ones who make the choice of disposal (ie the consumer)?
The problem with charging the producer for waste disposal is that the cost of disposal depends on how the consumer handles the waste they produce. It makes the determination of the cost of disposal at the manufacture level completely arbitrary. The manufacturer can contribute, eg by using recyclable materials, but the consumer needs to have an incentive to play their role in the cycle.
To make this work you need to put some cost incentive on the consumer. An example of this is the deposit refund scheme for drink bottles. The consumer pays for the waste they produce in the bottle deposit added to the price of the drink and can get it back by doing the ‘right’ thing by returning the bottle to a recycler. | 16 | 292 |
Gitlab for personal/lightweight usage | hi, i'm a cs student and i wanted to ask if gitlab is considered overkill or not for personal and lightweight usage compared to github or butbucket.
thanks. | IMO more important is what other people in your group/school use (students, professors) that you might want to collaborate/share with or if they have standardised on one platform for coursework.
In terms of personal usage it doesn't matter. | 26 | 18 |
ELI5: How does a scientist look at the skeleton of a dinosaur and definitively say "that ate meat"? | You can look at the type of teeth they had and extrapolate what they are. If they have flat teeth they ate plants (cows, deer). If they have pointy, sharp teeth, they ate meat (dogs, sharks). If they have booth, they are omnivores (humans) | 173 | 103 |
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isn’t it obvious that consciousness is ubiquitous? | If humans and other living things are not qualitatively different from any other objects in the universe, and consciousness apparently exists, then it seems to me exceedingly obvious that consciousness is not special to humans or animals, but that it is a quality inherently part of the universe. So why is this such a contentious issue?
EDIT: I guess i should specify that what i mean by consciousness is the subjective experience of being, like what a ‘philosophical zombie’ lacks.
EDIT 2: Thanks for the thoughtful responses, not quite what I was expecting but it’s good, this has got me thinking. | What do you mean by consciousness being ubiquitous? Ubiquitous compared to what? As far as we can tell at the moment, it's a property that only human beings (and possibly some other animals) seem to have. So it appears to be much rarer than many other qualities we come across, such as possessing mass or charge, for example.
If by 'inherently part of the universe', you mean that consciousness exists in our universe and is thus bound by the laws of nature, then that seems to be trivially true (as long as one is a materialist). If you mean that it is a property that other (non-human/animal) entities possess, then this assertion does not seem obvious, at least to me. There are all kinds of properties that belong to some things in the world, but not to all things: for example, the quality of being red. | 23 | 16 |
ELI5: Odd unanswered question about Metal rubbing metal. | Whenever two metal utensils rub together (forks, knives, spoons) or on a metal pan/dish, and I taste it, I taste this really strong metallic/weird thing. It's extremely unpleasant for me to taste and nobody else I know has the same problem.
I asked this question 5 months ago and nobody answered it. | The surface of almost all metals is attacked by the oxygen in the air to form a surface layer of metal oxide. Some types of oxides are much more visible than others such as rust in iron or tarnish in silver. Only a few metals such as gold and platinum do not normally react with oxygen.
The metal oxide layer on the surface prevents direct contact with the actual metal underneath. When you rub two metal things together, you temporary break apart the oxide layer. When you taste it before the oxide forms again, you are directly tasting the metal rather than the oxide which results in a strong metallic taste! | 19 | 35 |
How plausible is utilitarianism from a meta-ethical perspective? | On the face of it, metaethics has nothing positive or negative to say about utilitarianism, since utilitarianism is not a metaethical theory, but a first-order theory of normative ethics. You could have a dozen utilitarians who entirely agree on first-order issues, but who hold completely different views on metaethical issues.
Hell, even an error-theorist could be a utilitarian. Mackie's first-order views were at least in the neighborhood of utilitarianism. | 12 | 24 |
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ELI5: How do we know that someone "died in their sleep"? Can we tell they were asleep when they died? | Not an expert but took a class in forensic medicine. You look at the surroundings. If you see the nightlamp beside the bed toppled or pillow/blanket was thrown violently around, more likely than not the person did not die in their sleep | 143 | 130 |
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ELI5: How do iodine tablets purify water in a safe way for people to drink? | I know that there are iodine tablets to purify water, but I have no clue how. And how do they work in a way where it doesn't kill us as opposed to other purification techniques like chlorine? | Iodine, chlorine dioxide and bleach is strong oxidizing agents. If you add them to water they increase the pH and will dissolve the cell walls of any bacteria , parasites and virus. Your cells will be attacked in the same way but while the bacteria in the water is exposed for theirty minutes your cells will only get exposed for a few seconds before the solution gets neutralized by your stomach acid. And you have a lot more cells then there are bacteria in the water and are able to replace your cells. Adding to this you have a layer of dead cells which protects the live cells underneath. All in all you can handle the high pH much better then any bacteria in the water. However you can also dissolve an acid, for example vitamin-c, into the water once the iodine have done its job to neutralize the water again to make it more plesent to drink. The iodine and vitamin-c will react and form a powder that settles at the bottom of the container. | 12 | 15 |
Can anyone explain to me what precisely entropy is? | I know that entropy means that it is a measure of disorder but i cant really imagine it. Then if something has zero entropy like liquid helium. Does it mean that its in perfect order? And how are properties influanced by entropy both low and high | The best way to understand entropy is by considering the distribution of a system over the set of possible states. It is often said that entropy is a measure of 'disorder', however that is not always the most useful definition (there are many situations where it is not easy to understand what 'order' and 'disorder' mean).
We can look at the situation using a simple test case: the coin toss. Imagine that you are tossing a fair coin, say 1000 times; what is the probability that you get only tails? The answer is very small, 2^-1000 . However you may want to ask, what is the probability of getting any *particular* sequence of heads and tails after 1000 coin flips? The answer is again 2^-1000 . So what we have is a collection of 2^1000 states, all of which are equally likely.
But then, what distinguishes a state such as all heads or all tails, or alternating heads and tails from all other states? It is clear that each indifidual 'microstate' in this example is equally likely. However what we achieve from these descriptions is to partition the full set of 2^1000 (or however many) states into two unequal sets, one of which satisfies some criterion whereas the other doesn't. So for example there are only two states where heads and tails alternate for the entire sequence of 1000 coin tosses, but 2^1000 - 2 where they don't. So the full set of states is partitioned to a small subset which reveals some information about the configuration of the system, and a much larger subset where information about the microscopic configuration of the system is not specified.
Such is the basic idea. To translate this into thermodynamics you can think replace the sequence of coin tosses with the position and momentum of microscopic particles, or any other way you wish to describe the microstates.
In general the entropy of a given state *n*, S(*n*) is given by
S(*n*) = -P(*n*) log( P(*n*))
where P(*n*) is the probability of state *n* (this expression is sometimes called the "Shannon entropy" or the "information entropy", but it's quite general). The total entropy is then obtained by summing over *n*. For example, if the system consists of N uniformly distributed states, i.e. each with probability 1/N, the entropy is given by the sum over n of -(1/n)*log(1/n) = log(N)
This formula is quite similar to Boltzmann's entropy formula:
S = k log(W)
(where k is Boltzmann's constant, essentially a conversion unit between units of energy and units of temperature), W here can be seen as the microcanonical partition function. But in short, it gives the distribution of different microstates that results to the observed macrostate.
I hope this clarifies the concept for you.
| 19 | 41 |
CMV: The punishment for knowingly infecting someone with HIV or other potentially fatal communicable diseases should remain severe. | Quick back story, I'm from Australia, so this does not affect me directly, but my brother and I were having lunch and he brought up that California had recently reduced the law for knowingly transmitting HIV to another person to a misdemeanor with a maximum jail term of 6 months. It also changes the law surrounding the disclosure of HIV status when donating blood, stating that because blood transfusions are screened for HIV anyway, that you should not have to disclose that you are HIV positive.
I find this change to be absolutely egregious for a number of reasons. Some more obvious than others:
1. Knowingly infecting someone with a deadly disease should be classified in the very least as GBH, and should be treated as an incredibly malicious and deadly act.
I can only imagine that the penalty for deliberately subjecting someone to carcinogens would be treated much more seriously than the current California law, and I don't understand how you can differentiate between the two.
There is something to say about intent, as I do not believe that unknowingly giving someone HIV should be met with any punishments. But if you are aware that you have a condition that, if transmitted to other people, can be potentially fatal, then it is your legal and moral responsibility to ensure that you disclose that to anyone that may contract that disease as a direct result of your actions.
2. It is your moral and legal responsibility to prevent the spread of a preventable condition.
The most outrageous part of this is that you do not have to disclose that you're HIV positive if you want to give blood. This to me, is absolutely insane. I give blood every 2 weeks. I keep myself healthy in order to do so. The idea that I could continue to give blood if I had HIV is so bizarre that I just can't find any justification for why the law was changed. Now this is decriminalized. So hypothetically, I can intentionally try to infect someone who requires a blood transfusion with HIV and suffer NO criminal consequences. The justification for this is that all blood is screened for HIV anyway so why should it be illegal. This legal argument I simply can't fathom. I would compare it to saying that car's have safety features so why should it be illegal for me to intentionally run into another car with the *intent* to harm. I can't possibly think of a justification for why this change helps anyone at all.
3. Unfair discrimination is wrong, but if you're living with HIV, you should be subject to a certain level of discrimination that is correctly associated with your condition.
Nobody living with HIV shouldn't be able to happy life. But if you have HIV, you certainly have a moral responsibility to ensure that you do not infect other people that illness. Part of that is ensuring that you do not participate in activities where you would be likely to transmit the illness. There has to be certain parameters in place to ensure public safety. We do this with every dangerous thing in society, and with all the things we don't do it for, there is a very strong argument that we should. The idea that we should alleviate all requirements for HIV+ people to disclose their condition because it may lead to stigma is quite frankly a ludicrous change.
These types of disclosures should be in the best interest of the public and any disclosures should be with the intent of eliminating the condition from human populations.
4. The penalty for transmitting other deadly conditions should be *increased*.
This was a byproduct of me trying to understand why in the hell this change happened, and what I realised is that the law for transmitting other conditions like hepatitis (which can be fatal), is far less than HIV. I think that conditions like these (technically incurable, possibly fatal) should have the penalty for knowingly infecting someone increased. This is a very serious crime that shouldn't be tolerated under any circumstances. There is certainly room for a discussion on what conditions constitute what punishment, but I feel like that discussion isn't relevant in this case.
CMV on the above.
(also, don't mind the number formatting, reddit changed it automatically and I don't know how to fix.)
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> *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!* | What is more important to you? Malicious and negligent people being punished, or less people infected?
This is about people who may or may not have HIV. Getting tested means opening yourself up to legal consequences. If you just never get tested those consequences are not there and you also have plausible deniability from a moral standpoint.
Harsher sentences lead to less people getting tested, leading to more people being infected. | 15 | 41 |
[General Superheroes] Do heroes have their own 'turf' they defend? Do heroes contact each other to efficiently cover urban areas between themselves, and work out shifts so the city is never undefended? | I know groups like the Avengers and the Justice League have got organisation and strategic deployment on lockdown, but what about the (mostly) solo heroes? How do they decide who patrols which area, and would they discuss essentially their shifts for patrol so they can get adequate sleep/normal lives while another hero is out on patrol?
This is related to my last question about when Superheroes sleep, and I was wondering if heroes ever contact nearby heroes to organise patrol areas and shifts to ensure all heroes involved can take some time off to sleep/work/socialise whilst not leaving the city undefended. | Some heroes have their own designated areas. For example, Spiderman will cover most of Manhattan, but Daredevil is known for the more locally Hell's Kitchen area.
I don't think many solo heroes work out shifts with each other. More just begrudgingly accept the help they didn't ask for.
I know the Superhuman Registration Act was put together to try and set up more organized teams and have them set for certain areas to make it seem more like shift work, but that kinda got out of hand... | 22 | 18 |
But...what IS the anti-life equation? | Darkseid is always after it. I believe others want it too.
Yet it is just some sort of mathematical proof...? Which, spoken aloud, while somehow avoiding its effects on himself, what could he DO with it and how does it work? | To understand the anti-life equation there are some baseline things that need to be established. One is it requires an immense intellect to "get" it without being destroyed or rendered catatonic. The other assumption that you need to make is that magic and science are two routes to the same place, knowledge. A lesser bit of trivia is demonology; that is to say knowing the true name of an entity gives you dominion over it.
With these two (technically three) established the Anti-Life Equation is like learning the ultimate spell. In learning the true name of life, you have the power to strip it of all of it power. Darkseid wants it because he hates sentient life. He hates the idea of people being able to resist him. | 92 | 46 |
[Batman][Pokemon] How would Poison Ivy's plant-controlling powers affect grass Pokemon? | Well if we assume that all Grass types are Plant\animal hybrids. This is shown by their obvious sentience coupled with both plant appendages and features(flowers and leaves) as well as Plant abilities such as photosynthesis. she would be able to control them to some extent possibly greater the resemblance to the base plant the stronger the mental grip would hold. | 12 | 15 |
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eli5: If water is non-compressible, then why not use it in hydraulic machines instead of hydraulic oil? | Water has a few major issues as a working fluid:
1: it’s corrosive to metals and will dissolve seals and sealants.
2: it gets weird below 0C.
3: it gets weird above 100C.
We’ve engineered various hydraulic fluids to avoid these problems. You wouldn’t want to have your hydraulic cylinders all blow apart the first time you get a light frost overnight. | 5,891 | 2,699 |
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ELI5: How do restaurants, pubs, etc. process credit/debit card "tips". | Example: I'm in a restaurant. The bill arrives. I give them my credit card. Card comes back. I calculate and include my tip and the total on the check/receipt.
But I have never noticed a debit of the tip amount on my statements. How do they actually receive the tip amount? | When you give them your card, they put a temporary authorization on it to verify that the card is valid and has funds available.
After you've filled in your tip amount, they simply bill you for the total (price plus tip), which is what shows up on your statement. | 10 | 22 |
If the coronavirus (sars-cov-2) spreads through aerosols flying out of people's nose/mouth, why do we need a sample from deep inside the nose to detect it instead of just taking a saliva/snot sample from people? | Testing kits that check for the presence/absence of a virus work best if your sample is likely to have a lot of virus in it. There’s more virus deep inside your nasal cavity than in your mouth. There’s still plenty of virus in your mouth to infect someone, but not enough to produce a conclusive positive on a test. | 4,088 | 5,812 |
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ELI5: Why did the dial-up sound have to be played out loud? | Hi guys - I'm wondering why the dial up sound was even something we can all remember? I'm sure there are plenty of processes occurring with our wireless networks that could make crazy sounds but the computers specifically don't play them out to us.
Was the dial-up sound mechanical in nature and had to played out loud? like a mechanical hard drive spooling up?
I hope you understand, I found it hard to put down in words.
Thanks! | It contained diagnostic information- i.e. you'd hear things like "all circuits are busy" or if it was the wrong number, etc. There are also loads of retraining signals that can give an idea of how fast you are connecting, as well as noise on the line, etc.
Then after awhile (early 2000s) the cheapest software "winmodems" didn't have a speaker, and would instead play a .wav file of a 56K modem connecting successfully, which was pretty evil, IMHO. | 2,246 | 2,955 |
Faculty: What is the most important office politics lesson you've learned and how does it shape your current interactions with your colleagues? | Navigating office politics is a necessary evil. Let's help one another out. | Have a positive attitude.
Project positive intent.
Deliver results rather than activities.
Practice personal accountability.
Be sparing with commitments, and follow through on those you do make.
Find win/win solutions.
Be generous and genuine with praise when appropriate.
Share credit.
Tell the truth, even when it's hard.
Avoid causing others to lose face. Help others to save face.
Make eye contact.
Know the needs of the department better than your boss does, and do your part to promote success.
Don't worry about what's popular or who is trashing or praising you. Consistently do what's right.
Ask for help when you need it. Offer help when you know it's needed.
Don't say anything you wouldn't say with the object of your discussion standing in the room. | 41 | 41 |
ELI5: Why is "Z" called "Zee" in America and "Zed" in the rest of the English speaking countries? | It is the same letter and used the same everywhere, but we call it by a different name. Why did this happen to only one letter? | Different manners of speaking are natural in a language, England is home to a great many dialects, which were exported to the Americas. It happened to be that some forms of speaking prevailed in each place as English came to be more standardized, and these often differ between North America (and between regions in North America) and England. For example, although "diaper" is universally used in America over the English "nappy," the word "diaper" was first used as such in England. The non-American colonies, having close ties to the United Kingdom for much longer than the U.S., tended to emulate the U.K. speaking habits, which is why their national varieties don't differ quite so much as American and British English do.
In this particular case, we know that "zee" is first known from the 1670s, but it may have been in use earlier. It likely comes from the way the letter is pronounced in many words, whereas "zed" comes from the French name "zede."
It's worth noting there is no objectively correct way to pronounce words, and there is particularly no standardization for letters. | 891 | 3,811 |
ELI5: What exactly is IQ? | It stands for Intelligence Quotient and it is a scale that was created to help quantify intelligences and compare them to each other. 100 was set as the average, most common level of intelligence. The center of the distribution of intelligences.
How you define intelligence is another question entirely. There are many kinds of intelligence, and all IQ tests are biased in some way, but your theoretical IQ does exist as a rank of your intelligence compared to the population, even if there is no real way of ever knowing what exactly it is. | 14 | 20 |
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What's the difference between phenomenology and plain ole' descriptive writing? | What's the difference between phenomenology and plain ole descriptive writing? | Not a whole lot, because you certainly have to use descriptive writing skills to do phenomenology properly. That said, one can be doing descriptive writing without doing phenomenology. This is because phenomenologists describe the form of human experience *as form*, whereas descriptive writers can forego speaking of the form of human experience in favor of describing and illuminating specific things within human experience. As a quick example, we could see the latter in descriptions of a worker toiling in a field (the sweat of his brow, the ache in his back, etc), and we could see the former in descriptions of what it means to be engaged in work in general, as Heidegger loved to do, with the "readiness" of the implements the worker uses.
Your question is actually quite a good one, and explains why phenomenologists will blend literature into many of their works. Thanks for it. | 20 | 32 |
CMV: Calculators should never be artificially restricted in math, even on tests | Edit: wording of the title is confusing. I mean that in math classes above algebra 2, calculators should never be restricted
Restricting calculators in math class is dumb because there will never be a point in time where you have to solve something without a calculator and do not currently have one, or are without the means to obtain one. I am mainly talking about math above algebra 2, as understanding how numbers fundamentally interact with each other is important. The restrictions of calculators don't help students learn better, they just increase tedium.
In addition to this, all calculators should be able to show work when prompted, and should go through regular testing for bugs and the like. Class time devoted to teaching people how to work without a calculator should be instead be used to teach people how to use a calculator effectively.
People have access to calculators pretty much all the time, whether they be on a phone or online. When more advanced math is needed, there are online scientific calculators or you could just carry one around. | I think it depends on what you're teaching, and on what kind of calculator you're talking about. Being able to use a calculator effectively sometimes means being able to work without using one at all.
If you're teaching students how to do long division, for example, then using a calculator is pointless and doesn't help the learning process a lot.
If you're teaching algebra, then it's reasonable to let students use calculators that are only able to do arithmetic, because they should already know arithmetic anyway. But they shouldn't be using calculators that can do algebra because, again, it's pointless and doesn't help the learning process.
Doing math without a calculator can be tedious, of course, but that can be said of doing any kind of work. Doing pushups can be tedious too, after all, but it's necessary for getting stronger. Watching someone else do pushups (i.e. letting the calculator do the math for you) doesn't do anything to make you stronger. Calculators, when used properly, are mostly a labor-saving device, not a replacement for the ability to do math.
The reason that it's important to be able to do certain things entirely without a calculator is because, if you can't do that, then you won't necessarily know how to correctly interpret the answer that the calculator gives you. I've seen this when grading homework assignments for undergraduate college students. You can often tell which ones used Wolfram Alpha to do calculus for them because they put down really weird (and wrong) answers involving special functions and edge cases. Wolfram Alpha itself isn't doing anything wrong, it's just that the students who use it without fully understanding the calculus aren't able to correctly interpret its output in the context of the problem that they're trying to solve. The ones who can actually do it out by hand never make this mistake.
And, really, this only becomes more important as you do more advanced kinds of math. The easiest and most reliable way of debugging advanced mathematics algorithms is to take a simple example and do it out by hand, and then compare what you're doing to what the computer is doing. If you can't do that then you're in for a bad time. | 16 | 24 |
ELI5: How did English become the universal language of science and aviation? | The International Civil Aviation Organization, a UN agency, simply chose English, or rather a subset of English called "Aviation English", as the recommended language for pilots and controllers in 1951.
While it was just a recommendation it was widely adopted as post accident investigations before then had found language and communication in general was a big contributor to accidents.
So, the main aviation organization just chose it. ICAO even offers Aviation English proficiency tests.
As for science papers, that arose somewhat naturally. Many papers coming out from research during post-WW2 were written in English. To read those papers, you had to speak English, and most prestigious journals were in English. If you wrote papers in other languages, they wouldn't be cited as much. So, English became the de facto language for reading and writing. | 41 | 30 |
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CMV: a "good actor" has more to do with writing, directing and overall production than with a particular actor's skills. | Now I'm not saying that actors are not talented and that it is not difficult to act out difficult scenes. My qualm is with the separation of "good actors" and "average actors".
Matthew McConnahey is the obvious candidate who was thought of as nothing special until he had an opportunity to work with a good script, good production and good directing. Heath Ledger was another example. Robin Williams, too, would not have been thought as much more than a comedian until given the right opportunity. Or Will Smith. We may soon be saying the same for Jesse Eisenberg.
Given the quality of script, the careful directing, the number of takes and feedback and cues an actor may take to get a scene right, the music which can be an emotional trigger; it is hard to imagine any professional actor who could not be coaxed into giving stellar performances.
Obviously people will cite examples to the contrary, but to compare Gary Oldman who is widely regarded as a master actor, I've recently noticed the previously unremarkable aussie actor Joel Edgerton being cast as Rameses in the upcoming Exodus, and I think that it may not take much to make a competent actor "chameleonic".
Basically, I believe any competent or trained actor can be coaxed to give outstanding performances with the right directing and production. There is less variety in the capabilities of professional actors than the fandom of A-listers suggest.
Edit: to clarify my position: I think there is less validity to the claim "X is a brilliant actor and Y is a bad or average actor" than there is to "X got a good role, script and director whilst Y has been unable to find a role or script he can really shine in."
Edit2: okay guys, took a bit of discussion but you did change my view. A few guys highlighted the inverse of my position, good movies dragged down by bad acting (Keanu in Dracula is one I'll never forgive) and average movies saved by an outstanding performance (no one would be mentioning Good Morning Vietnam without Williams). But most importantly was the talk of theater, which removes all of my talk of takes, editing and music and lets it be the bare actors. I never considered that, but it is absolutely contrary to my position and changed my mind. Dishing out the deltas for the 3 who changed my view. | I think there is definitely a major impact on an actor's performance when given a good script and good direction, but there is also a skill to the actor themselves and they way in which they go about their work.
A good actor will try to understand the character and their motivations, and will give feedback to the writers and director about how a line feels and sounds in that context. Also, a huge thing about great actors for television and films is their ability to self-choreograph otherwise improvised motions. Something as simple as how they hold a prop like a cigarette or a drink, and the timing of when they take a sip in the dialogue, and making that consistent goes a long way to making the editor's life a hell of a lot easier when editing for continuity. A lot of novice actors will move around at random, just reading the lines and trying to act as it comes to them. When you take the footage back to edit, it can often be a mess trying to line up shots where the actor's arms or legs are in the same position at the same word in a dialogue, and you end up having to edit around them instead of editing around how it would feel best.
But of course, any production is a culmination of all its constituent parts. | 105 | 431 |
CMV: White privilege does not exist | I do believe that there has been systemic discrimination against minorities such as blacks that has been both codified into the law (slavery, Jim crow, etc) and has been part of the social fabric of the country. I believe that great improvements have been made as of 2014, but that the reverberations of past policies can still be felt. However, I don't consider "white privilege" to be an accurate or a useful term. I'd suggest "rich privilege" or something to that effect. There are all sorts of victims and unlucky people out there, and not all of them are part of an officially recognized minority group. In fact, I'd argue that focusing only on members of minority groups is a form of the same flawed collectivist thinking that actual racists employed. In my mind, affirmative action-esque policies should target low income people regardless of race. A college admissions officer shouldn't give special consideration to the black son of a neurosurgeon over the white son of a single mother (I realize some people might actually concede this point on the basis of who's had more difficult circumstances, but may still argue for the former candidate in the name of diversity. While that's a fair point, it'd be part of another discussion.)
I don't care for the term "white privilege", because it is blind to the fact that there are tons of white people from non privileged backgrounds. Some people may argue that even poor white people are less likely to be stopped by the police for a stupid reason, but I personally don't see arguments like that as worthy of sustaining this "white privilege" meme. I think the "We are the 99%" movement succeeded because it resonated with everyone who had been locked out of the country's power structure more or less due to the circumstances of their birth. But I think "white privilege" is divisive, and pits real people with their own unique challenges and difficult circumstances against others.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[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)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Your OP features one of the most common misconceptions regarding white privilege, that it's something that only applies to the upper class. The truth is, white people of all levels of class have many privileges that black people of even the upper class aren't guaranteed.
The very fact that it's not easy for you to pick out instances of white privilege operating in the lives of more disadvantaged white people is a testament to what a privilege it really is to be white.
For example, a white person can walk into a store and browse around without buying anything and never have to think twice about whether someone is watching them or whether their movements are considered suspicious enough to warrant them being accosted by security. A black person of the same economic background walks into a store and often assumes he's being watched closely (and would be correct quite a bit) and has to go out of his way to not look suspicious.
A white person can get pulled over for a moving violation and have his only worry be how much it will hurt his wallet, a black person has to fear for his safety and whether he's going to be arrested on some trumped up charge for what would only warrant a ticket for a white person.
A white person can confidently put his name down on a resume never thinking twice about it. A black person has to worry about whether putting down Shondra on a resume may cost her the position in spite of her qualifications.
When you look at all these things laid bare it seems so obvious that white people have privileges that blacks don't. However these things usually aren't laid bare because they're things that white people continually take for granted. They need to be reminded of them in conversations about privilege because naturally not ever living as a black person it's hard for them to tell that they have a different level of privilege then black people.
Money and social status certainly factor in. Rich whites have privileges that poor whites and blacks don't have. This does not negate white privilege at other economic levels. | 37 | 23 |
[Dune] WHat does spice acutaly do? | I mean in laymans terms what does it do? Paul can sort of see into the future but no one else can, except the merchant guys become weird creatures that have to live in a tank and everyone else just gets blue eyes so i mean i am a little confused. | It basically does the following for everyone:
* Grants longer lifespans
* Makes you more healthy, basically a better, stronger and smarter you.
* Better reflexes and perception.
But for some people it also unlocks mild precognition. Paul and the Spacer Guild both relied on spice to give them an edge. Spice essentially allowed the Navigators to predict what FTL jump was safe by looking a minute or two into the future. It also changed them from having a human form into, well, the Navigators. If you've committed to spice, you have to keep taking it. Otherwise withdrawal is fatal. | 46 | 28 |
How does electricity from a specific power provider get to me, when other power companies use the same power lines leading up to my house? | So for instance, I used to live in an apartment complex where you had to choose and separately pay for your own electricity provider. So for my apartment, I chose electricity provider G, but other apartments around me chose a number of other energy providers, T, C, and Q. All the electricity came to the apartment complex via the same power lines leading in, so how can anyone actually know that the electricity I paid for, going into my apartment, actually came from a power plant from provider G? Because my understanding is that electricity in power lines is pretty much the same no matter if it's generated from a dam, a coal plant, a nuclear plant, or a wind farm, so how is it differentiated, if at all? | Your power meter is installed by your company and your neighbors meter is installed by theirs. Power is all the same and those companies with the meters then pay the company that supplies the power to the lines after you pay them for your usage.
Just image your power meter is a gas station. You pay the gas station, the gas station pays their supplier and so forth back to the source.
​
edited for clarity. | 30 | 29 |
ELI5: How do cinematographers do forced perspective while keeping everyone in focus? | I've heard of this technique before, where you place one actor much farther from the camera than the other to make them look much smaller by comparison. It makes perfect sense to me except for the question in the title.
Wouldn't having one actor near and one far require the camera to focus on the nearer actor leaving the far away actor blurry and out of focus, or vice versa? | By using a higher f-stop (smaller camera aperture) and raising the amount of light.
The reason things get out of focus, and the reason we need to focus in general, is because light bouncing off the same object comes into the camera from all different directions and we need to focus that into a single point on the film/sensor. The smaller the hole that the light passes through, the fewer possible directions it can be coming from and therefore the less the lens needs to focus the light. Small holes mean less total light getting in though, so you have to turn the lighting up really bright to compensate. | 65 | 86 |
ELI5: What goes into rendering a font? | There seems to be a lot going into just displaying a font on a computer screen, e.g. Cleartype. What other things go into rendering a font? | When rendering text, it first needs to be split into chunks based on left-to-right and right-to-left languages. This is to make sure that you can mix both kinds in a single paragraph, without some words appearing to be backwards. One library which can take care of this is FriBiDi.
Next, the application needs to process Unicode groups. For example, emojis now support skin tones, which are a second Unicode code point following the emoji which converts it into a slightly modified version. The text contains the symbols <smiling emoji><dark skin tone> and is converted into a single font glyph <dark smiling emoji>, if the font supports it.
Another example are modifying characters, which are how some people get those usernames with a huge tower of random accents above some letters. The text <letter a><combining caron accent><combining caron accent><combining caron accent><combining caron accent> can't just be rendered in a line, another function positions the accents above the previous letter, again based on how the font specifies it. This can be done with the HarfBuzz library.
Next you have to measure your text. Letters are typically placed along the baseline, which is an imaginary version of the line you had to write on in school. The font specifies how much further to draw each character after the previous. You have to measure the text length to perform word-wrapping, or to justify or center the text.
Now you can actually start rendering. You pick your start point (origin) and start drawing letters. Each symbol (glyph) has a certain bearing, which is the vertical and horizontal offset where you start drawing it relative to the origin, and an advance length, which is how far to move the pen. Accented characters can be drawn at a relative position from the previous glyph instead. This can be done with the FreeType library.
Another complication is kerning. For example, the letters AV overlap a little, there is a special width adjustment just for this pair. Without kerning, the gap would look unreasonably large (like V A). The r/keming sub is supposed to showcase issues like this, but lately has had other content posted as well.
Since most fonts are outline fonts, you first have to convert this outline to a bitmap off-screen. This is similar to the pen tool in Photoshop. You have to scale the outline based on your font size and align the shape to the pixel grid to prevent it from appearing blurry. This is called hinting. ClearType is Microsoft's patented version of subpixel hinting.
Once you have the bitmap for each glyph, you can just copy it to the screen location determined above.
There are also recent advancements with color fonts (which is how emoji fonts can give you colored emoji outlines, even if your text color is black), and variable fonts, which let the designer modify the font parameters, e.g. the thickness of letters. | 21 | 27 |
ELI5: When colour fades from fabric and other printed materials, where does it go? | Nowhere, color isn’t a material, it’s just a propriety of how done materials reflect light, if those materials change in some way, be it chemically (like with bleach) or by exposure to ultraviolet light, they reflect light different and the colors fade | 19 | 16 |
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Why does the aroma of ground coffee permeate a plastic bag but not say, orange slices for example? | Nearly every workday I grind up freshly roasted coffee at home, and dump the contents into a zip loc baggie to take with me to the office. I frequently also do the same for other very aromatic things, like a fresh cut orange, or grapefruit, or a warm muffin. None of those other things radiate their own aroma from within that zip loc baggie. The coffee however, might as well leave the bag open it smells so strongly. I have been very careful about constraining the contents to the inside of the bag, going so far as to rinse the outside of the baggie just in case the smell is coming from the exterior. It is not. What gives? What else does this? Making me crazy! | Plastic is a wonderful material for containers; lightweight, easy to form, reasonably inexpensive.
What it is not is unreactive. You can get chemically inert plastics but they are more expensive and heavier, neatly removing the benefits to the packaging industry. Since most plastics are organic polymers instead of inorganic solids like metal and glass containers, they can and will react with many other substances. Small volatile molecules are capable of (slowly) migrating through common plastic films, and long-chain organic molecules (oils) will cheerfully bind to the plastic directly. This is why tomato sauce will stain your plasticwear red; lycopene is a long hydrocarbon.
| 84 | 79 |
CMV: Living standards will decline in the future | The past century is overall a success for humanity, as poverty rates declined while literacy rates and life expectancy improved. However, we face multiple challenges in the future that I believe will negate improvements in our quality of life due to development and technology improvements.
The first, obvious challenge is climate change. While it won't end humanity, it would certainly exacerbate existing problems. It is quite likely parts of India, the middle east, Africa and Central America will become nearly uninhabitable due to heatwaves and water shortages. This will trigger more conflicts and likely a refugee crisis that would make the ones in Europe and the US southern border look tame. At the same time, countries will have to deal with rising seas, which threaten some major cities and would cause severe economic damage. If this was the only of our problems, we may be able to handle it but there are several more which the media do not adequately discuss.
The current period of economic expansion will eventually end. However, most countries do not have the maneuvering room they did in 2008. Interest rates are already low and most governments are running a deficit and have high debt, so there is also less room for fiscal stimulus. In fact, it is plausible the US or some other major economy may be faced with a debt crisis since their aging populations force them to spend an increasing amount on pensions and healthcare. In all, it seems the next economic crisis will be especially painful for my generation as it would be more severe and have a slower recovery.
Automation is also a concern. The technology improvements would boost the economy but would also displace millions of workers such as drivers and cashiers. It would probably further increase inequality as well. From the research I have read, it is disputed whether automation will result in a net gain or loss in jobs but either way, the job displacements will be a huge social crisis which needs to be addressed within the next decade.
These challenges requires competent governments. Unfortunately, authoritarian governments need to control the narrative to survive so they are unable to deal with their mistakes. Western democracies are crippled by increasing polarization so they have difficulty making reasoned, informed decisions. Instead we get populists who advocate policies that are "neat, simple and wrong".
The combined effect of these problems may be enough to reverse the gains we have made. I try my best to remain optimistic but thinking about these problems make it difficult. What have I missed in my analysis that would make the future seem less grim? | Book recommendation. Factfulness by Hans Rosling. He’s the guy that, after 14 of consulting with the World Bank, finally got them to stop using the term developing countries. It is the USA and other nations at the top of the inequality curve that are grappling with living standards, and we project our histrionics on the globe. The book goes into perceptual biases that are obscuring phenomenal progress globally overall. Check it out? Stand in a bookstore and read the introduction? | 30 | 51 |
ELI5: If fish are cold blooded, how do some species function at depths of over 900 meters where the temperatures are 0-3 degrees celsius? | Fish have a unique chemistry. It has been determined that often their blood is similar to antifreeze. This makes them able to function at colder temperatures than a lake trout or some similar surface water species. | 71 | 187 |
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ELI5 The effects of isolation for years at a time does to the human mind and body | Human contact is most crucial during childhood. Children who are raised in complete isolation (such as in extreme cases of abuse) tend to be stunted mentally and physically, and may never learn to talk. Reading stories about instances of feral children can give you lots of examples of this.
People who were raised among others but choose to isolate themselves in adulthood seem to fare significantly better, though even then it seems to lead to poor mental health. People in the least populated states in the U.S. have higher rates of depression and suicide. People that make a deliberate choice to live completely alone in the wilderness sometimes find happiness and peace doing so, but it may negatively impact their social skills in the long run, and they may come across as odd or inappropriate. It takes enormous mental fortitude to keep yourself mentally and physically fit when you have no one around to talk to or assist you in any way, but some people manage it.
Adults who are isolated against their will can suffer psychotic breaks, with their brains providing hallucinations to fill the hole where socialization should be. Social skills degrade the longer the person is isolated. Many people stop taking care of themselves from hopelessness and lose mobility and strength, and their immune systems are vulnerable to disease.
Some general physical effects could be weight loss due to discouragement, hunched posture, trouble speaking, and neglecting personal hygiene. | 14 | 20 |
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If Hubble can make photos of galaxys 13.2ly away, is it ever gonna be possible to look back 13.8ly away and 'see' the big bang? | And for all I know, there was nothing before the big bang, so if we can look further than 13.8ly, we won't see anything right? | The early universe is opaque, so there's a limit to how far you can see before you hit this opaque region. The furthest we can see is back to the point in time when the universe got cool enough and thin enough that it transitioned from opaque to transparent. We're looking back in time with distance, so what we see is a sort of wall behind everything, a kind of *background* to the universe.
In this background we see the surface of the very hot gas that our portion of the universe evolved from. Over time, the light from this background has been redshifted down to microwaves. So this is the *cosmic microwave background*, and we have lots of maps of it.
One thing to keep in mind is that telescopes don't see "far", they're just good at capturing lots of light to see dim things, and at magnifying things to see things at higher resolution. So a low resolution telescope will still get the light from lots of distant galaxies, it just won't resolve them well enough to see them as individual galaxies - they'll just all get muddled up together. And a small telescope just won't capture many photons from these galaxies at all.
But the cosmic microwave background comes from all directions, so it's not too hard to detect. Newer instruments have just been able to map it in higher precision. | 7,185 | 14,138 |
[MCU] Why didn't Asgard rebuild to some modicum of its former glory in the 5 years since coming to Earth - was there no one left who knew the intricacies of things like Soul Forges, anti-grav chariots, and the Rainbow Bridge? | First of all: We don't know if the materials needed to build these even exist on Earth, let alone in Norway.
Secondly: The Asgardians are still recovering from the destruction of Asgard and the attack by Thanos, so they prioritize building shelter and creating supply routes over unnecessary pomp. | 597 | 734 |
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How can I explain to my new employer that their spaghetti architecture needs to be changed? | So going into a new job, they said that they used to have a monolith, but have since split it up into several micro-services. But now that I've actually gotten a look at it, I see that they keep all the data-access and mediator code in one shared library, then include that in every single one of their services; ui and device back-ends included. So every service that wants to do something will directly contact the databases or external integrations of the other services. It seems like all they did was pull the business logic out into services so that they can scale those appropriately.
&#x200B;
I know this is wrong; it's a big ball of spaghetti. From all my years of learning about micro-services, I know that services should communicate with each other using their API or events, and not directly connecting with the internals of other services. My boss says he's open to change, but only if I can explain to him how the aforementioned architecture is better. How can I do that? Blog posts, conference videos, or written explanations would all be helpful. Thanks. | Identify the biggest risks and timesinks, and improve this. Whether it be by setting up a testing environment, automated testing, automated deployment, etc.
Don't fall into the trap of wanting to 'do it the right way' and try to redo the whole thing. Inertia will catch up with you and you will end up with a different kind of spaghetti. | 18 | 24 |
ELI5: How did the Polynesians have enough food and water to travel such great distances in canoes and why did they do it? | What made them think they'd ever find another island in the Pacific Ocean? It seems like many of them would have died trying. | Carrying enough food isn't really a problem, especially 2,000 or 3,000 years ago, when there were lots more fish in the sea.
I sailed 12,800 km, from Panama to New Caledonia on a 11-meter sloop.
We left with 100 liters of fresh water for 4 adults. We caught rain running off the mainsail and put it in the tank. Never was short of water.
We towed two fishing lures the entire time. We caught good sized tuna every other day, usually two at the same time. We would catch one or two dorado every 5th day or so.
As we emptied the jars of vegetables and other foods, we would refill with fish and a court bouillon, then water-bath can the jars on the boat's stove.
We arrived in Noumea with all the jars full of fish, which were given away to the skipper's friends. | 41 | 30 |
I believe Islamic culture is incompatible with modern society. CMV. | I believe that the Islamic/Arabic culture is at best, incompatible with modern society, and at worst, actually a threat to a tolerant way of life. I base these views on ~~3~~ 2 main points.
* 1. Women are regarded as lesser creatures, and must be subservient to any male, including their own sons.
* 2. Any woman who does not act in an approved manner, even if not a member of that culture, is met with hostility and derision.
* 3. ~~In areas with a high concentration of this culture, there are currently large movements directed towards supplanting the current law with Sharia law, which is antithetical to a modern, equality-driven society.~~
EDIT: [I stand corrected.](http://www.politico.com/news/stories/1010/43451.html) My apologies for the misinformation. However, my view still stands based on the first two points.
Therefore, I don't believe this culture should be respected or acknowledged in modern society. CMV.
| You know, places in Indonesia and those surrounding areas have millions if not billions of people that are Muslim. That area of the world is extremely technologically advanced and get along with surrounding non-muslim countries like South Korea, New Zealand, Thailand, Vietnam, Australia and Japan without much issue.
Traditional Christian values hold not only the same views of women or religious law but they hold the same people in high regard. Abraham, for example, is highly regarded in Christianity, Judaism and Islam. They have nearly identical values but the "bad stuff" of their texts isn't usually followed. When it is you see situations like in some areas of the Middle East. When it isn't, you get situations like Indonesia and surrounding areas. | 49 | 75 |
ELI5: When you are in the hospital and get an IV how does your body "taste" what's in the IV? | For example, when you get a saline IV and you can "taste" the sodium while the IV drips. Just curious on how this happens internally in the body. | If you increase the sodium concentration in your blood, all the (relatively thin) mucosal membranes in your nose and mouth can pick up on that, as that blood courses through them in the course of regular circulation. At the end of the day, all that taste is is electric signals which fire when a molecule binds with a receptor, and a lot of the binding is based on simple stuff like charge and molecular shape. If you think about it, it's very evolutionarily beneficial for the body to be able to inspect the chemical makeup of its blood. | 39 | 15 |
What were Spinoza's views on God? | I remember hearing an opinion that Spinoza saw God as an entity that was constantly changing throughout all of eternity, but I wasn't able to verify this. What were Spinoza's views on God? | > What were Spinoza's views on God?
Roughly, Spinoza's concept of God begins with a fairly traditional view: God is an absolutely infinite being, eternal and possessing being through his own nature without dependence nor origination in anything else, unlimited by anything else as regards his power and in any other sense, and in and through which all else that is has its being. He then takes this view in a direction which challenges orthodox theology, by arguing that God's unlimited power implies that by necessity he does all that he can do, which means that he does not refrain from doing anything, which means that he does not exercise a providential concern in enacting a decision to create and a decision of what to create and what not to create. This move rejects orthodox commitments to God's providential interest in creating and creating a certain kind of world, and binds the existence of world in some sense closer to God as a necessary act of his.
As infinite, God, and by a certain extension the world that is his act, may be conceived of having any number of natures, but as humans we can conceive of two: either conceiving of them as extension, in which case we think of the world in material terms, or as understanding, in which case we think of the world in terms of ideas. As they result from conceived the same things now in one way then in the other, there is a strict parallelism between matter and ideas without the one being reducible to the other. | 44 | 31 |
Are conferences something you GET to do, or something you HAVE to do? | My colleagues generally seem to get really excited to go to conferences, but I don't really see what's appealing about them from a personal perspective. It just seems like its travelling a long ways and spending a lot of your employer's money so that you can spend 10 minutes talking about your work to people who are mainly just waiting for their turn to talk about their own work, fielding some narcissistic questions, and maybe getting a decent dinner as part of the deal.
I'd just as soon not bother with the whole exercise. But it's still early in my career, and I can't quite tell whether that would reflect badly on me. This is particularly the case since most of my colleagues talk about conferences as a fun thing, rather than something they do as a job obligation.
So what's the deal? Can I get away with not going to conferences? Or should I see it as another job duty? | Conferences have several benefits for attendees:
* If you present, this is an opportunity for you to gain name recognition, both within your field but also at larger conferences outside of your immediate field.
* Attending other presentations informs you about the most recent work done in the field, which may not yet have been published.
* Collecting many experts in your field in one location provides an excellent opportunity to network with potential future employers or collaborators, depending on just how early in your career you are. Getting face time with these people goes a lot further than a simple email will. This includes both meeting people on the conference site, as well as socializing over meals or drinks (it is a long-running joke in academia that many proposals are written on the backs of bar napkins!).
* Many people treat conferences as a sort of vacation, skipping talks or sessions they find less interesting to spend the time sightseeing. Some academics will even bring their spouse along to enjoy time away from their children. For many, the business of an academic schedule affords little time for a "proper" vacation, so they will take whatever opportunity they get.
You *can* get away with not going to conferences, but it will more likely than not just make it more difficult to advance in your career. If you really dislike conferences, you can always attend for only a day or two, just enough to present your work, attend the most relevant talks by others, and perhaps meet with one or two key colleagues to discuss potential collaborations or job opportunities. | 47 | 28 |
ELI5: Why does cooking things using different sources of heat (i.e. pan seared, grilled, smoked, oven roasted, etc.) produce different tastes? | I've noticed that people always say the food tastes better, or at least different when cooked (grilled) outside or when camping (over an open flame), and I agree, but I don't why it that's true. Does it have to do with what is being burned to create heat, radiated vs conducted heat, temperature, or something else entirely? | There are two classes of reason. In the first case, of which smoking meat is the best example, *material from the heat source winds up in the food.* Barbecue contains smoke-stuff, and that smoke-stuff has a distinctive taste.
In the other, it all comes down to just how hot the food gets, and how long it stays that hot. Food cooked right on top of charcoal, will have parts that get *really, really hot,* at least where it was right up against the coal. Food cooked in a 400-degree oven, though, won't have any parts that got hotter than 400°.
Naturally, there are combinations of this; fried food has a distinctive flavor that comes from the oil, but also a particular pattern of how it took on heat from the oil. And different kinds of charcoal- some people swear- give different flavors to the meat they cook. | 120 | 389 |
[WH40k/Mass Effect] The Reapers waiting in dark space make contact with a Tyranid Hive Fleet. | This question has three possible sets of parameters, answer which ever one seems most interesting to you.
1.Tyranids arrive right before Mass Effect 3 (in ME universe).
2.Reapers make contact with Hive Fleet Kraken (40K Universe)
3.Reapers make contact with Tyranids in a "neutral" universe where no other factors are taken into account.
| The Reapers are eaten. The Reapers are biomechanical, containing sufficient organic components and reserves to warrant being consumed. They are also infinately fewer in number than the Tyranids, and still bound ny relativistic limitations during combat. In all cases, they would be consumed, their non-organic components left floating in space unless easily digested.
The only complication would lie with their Indoctrination procedures. However, these were shown to be rather ineffective against the Rachnii, which required more direct means of control, so what little information we have about Indoctrination indicates a vulnerability to hive-consciousness, thus potentially rendering the Tyranids immune.
Even if not initially immune, the Hive Mind would develop a way to block the psychic interference.
*edit* If, in scenario 2, it was ONLY Hive Fleet Kraken, the Reapers may win. They probably have enough firepower to neutralise a single Hive Fleet, if gathered together. | 17 | 20 |
How does one go about becoming more comfortable reading opposing views? | I happen to like philosophy a lot, but I'm too wrapped up in my own beliefs about things to be able to read much of it. I have a really bad habit of accepting whatever I read as being true while I'm reading it, and if it challenges my pre-held beliefs, I'm emotionally and mentally drained by it. I was wondering if there's any methods to "turn off" those beliefs temporarily to approach arguments more charitably and objectively, or if good philosophers are simply gifted with the ability to suspend their beliefs.
I apologize if this is a bad place to ask this question, I just think philosophers would have the best advice on this (if there's any to be given). | you're not going to get any special advice for something like this. what you're asking is: "how do i begin to think critically?"
the only worthwhile answer is: by thinking critically more, probably.
you're not really doing philosophy at all if you are reading others' arguments and 'believing' them, or ignoring others' arguments because you want to believe what you already do. you're just putting stuff in your head. try challenging the authors' opinions and your own. attempt to provide counter-arguments. don't read something and let it blindly affect your views and don't let your biases affect your views. a really great pertinent quote by schopenhauer: "“Reading is merely a surrogate for thinking for yourself; it means letting someone else direct your thoughts. Many books, moreover, serve merely to show how many ways there are of being wrong, and how far astray you yourself would go if you followed their guidance. You should read only when your own thoughts dry up, which will of course happen frequently enough even to the best heads; but to banish your own thoughts so as to take up a book is a sin against the holy ghost; it is like deserting untrammeled nature to look at a herbarium or engravings of landscapes.”"
at the end of the day, you can decide whether or not you want to pursue truth or not. being a critical thinker takes some practice because we don't think like that automatically. | 16 | 18 |
Why are we looking for exoplanets? | We can't live on them considering the distance alone, so what are the current goals in the exoplanet search? Just to learn about the universe? | Being able to get a better handle on number, location, size, and make-up of expolanets is fundamental for a number of reasons. It gives us a much better idea of how common other life might be in the universe. It gives us perspective on how 'special' the Earth is. It allows us to better understand solar system formation processes. And, perhaps most importantly of all, we find out something we didn't know before. | 48 | 27 |
ELI5 What is the difference between Displacement, Distance and Distance Travelled? | Displacement is a vector and distance a scalar, but how else can you differentiate between them in the easiest possible way? | Displacement is the difference inbetween your starting location and your ending, including th direction. If you run around the block and end up back home your displacement is 0
Distance traveled is how many meters your feet or whatever actually moved you. If you run around the block and end up back at home your distance is a block. No direction. | 32 | 22 |
ELI5: Dependent versus independent variables | I swear, I just for the life of me could never understand the difference between the two in a way that stuck with me. I need a literal ELI5 here. | Independent variable: the variable that changes separately from other variables, which means you are changing it.
Dependant variable: the variable that changes due to the change in the independent variable.
Example:
The setting on your stove is the independent variable, how fast the water boils is the dependant variable. | 10 | 33 |
ELI5: WHY DO SOME books and news articles start the first few words in all caps? | I've always seen this in "classier" books and news publications, but I never understood why they did it, or what the origin was. Sometimes it's even in larger print. It seems random when it happens, or how many words they capitalize.
Thanks in advance! | When you have many articles clustered together, it makes it easier to find where they start.
In books, where chapters start in mid page, it can help find the where they start.
But mostly it is just a style. | 10 | 16 |
What do I need to LEARN to become a successful computer programmer? | I've tried searching this question on Google, but all I get in the search results is "How to become a computer programmer," or "What you should study in school to be a programmer," and stuff similar to that.
I have already gone through school and I got my bachelor's in math. My question isn't how I should start, because I already know some computer languages, like HTML, CSS, Java, Python, etc. I have no problem learning things on my own, because I learn very easily.
My problem is that I have no idea what I need to learn. I've got some languages down, but that's pretty much it. I don't know how to make a program, or do anything practical; just how to code.
My question is what should I teach myself before I begin applying to jobs? I know every job requires different things, but what are some absolute must haves in every programming/software developing job?
If anybody happens to have an answer, I would tremendously appreciate it! | You *cannot* learn to be a successful programmer by studying, only by doing.
To be a good programmer, you need to know a bit about algorithms, data structures, software engineering best practices, and some math. But personal experience is crucial. Plenty of people watching the super bowl understand the aspects of the game: the rules, the strategy, analysis of each player's performance, and even the politics of the sport - how many of them could be described as football players?
The trick is - what do you want to do enough to practice it? Do you want to be a mobile apps developer? Write a few mobile apps - Android has a free SDK with tutorials and documentation. Games? Unity or Unreal Engine are both a good place to start. Don't know? Try mocking up some small demos in Python with PyGame or what have you. Your imagination, curiosity, and drive will have to sustain you through a process of writing, confusion, and enlightenment that you can't get by trying to study programming the same way you might study biology or history.
Which kind of companies do you want to work for? Depending on what your goals are, there may be tutorials out there that could get you started. | 21 | 19 |
Why is accessing some random element near the start of an array FASTER than accessing a random element near the end? | I know they are both O(1) complexity, i'm talking at the hardware level here.
I know the difference is also very, very, very small.
Just recently I was doing a leetcode challenge one of which was a solution where lots of random access is done near the end of a 2D array. I found doing the exact same solution except from the front was \~10-20 ms faster and i'm talking consistently faster. This was in C++ with vectors
I then setup a test in python, and initialised an array of size 1 million, with random elements. I timed random element acccess near both the front and back, and the front of the array consistently produced faster results. I made sure the access was random to eliminate the compilers ability to optimise via caching etc.
Why would this be? I have always had the assumption accessing anywhere in memory should be roughly consistent.
Thanks for any input. Happy to share code if requested. | The vector itself has some metadata, such as total extent, bucket size, and an array of said buckets(buffers), and this metadata is allocated near the start of the memory block. So, you access a vector, it has to touch the metadata (object properties) first, then access the proper place in memory. Elements near the start are already in the L1 cache since the object header was just accessed. Elements near the end are on different pages / different places in the RAM bus, the mother board's memory controller typically has a RAM cache too.
TL;DR: Similar place in memory accessed twice is faster than two vastly different pages of memory accessed in succession. | 67 | 58 |
What Ancient Greek should one read before beginning Nietzsche? | The title says it all. I would really like to read and fully understand Nietzsche's works, and it appears the consensus is that a background in the Ancient Greeks is necessary for that; so which ones should I read prior to attempting Nietzsche? | Plato, first and foremost. Nietzsche engages with Plato's works more than any other Greek philosopher. Then the Pre-Socratics, especially Heraclitus, who Nietzsche held in great esteem. After that, the Sophists.
Outside of philosophy, Thucydides. Nietzsche praises him for his unflinching realism. Also, some knowledge of Greek tragic theater.
And in general, just a knowledge of Greek culture and society would be beneficial.
You don't need to read all of this stuff first, but it's helpful. If you want a shortcut, just read Plato (and Heraclitus). | 20 | 20 |
How is wealth non-zero sum? | I'm having a difficult time conceptualizing how, in theory, everyone could gain wealth over a period of time. Where is the wealth coming from?
Similarly, I can't conceptualize how we as a species used the Industrialization Revolution to create so much wealth. Where did it come from? I understand the Industrialization Revolution itself.
Thanks | Simplifying things, wealth is just the usefulness stuff and it is both possible for us to make more stuff over time and make our stuff more useful to us.
1. We can "discover" new existing stuff -- think natural resources --, by doing this we have increased the amount of stuff that we have and not changed the amount of stuff other people have.
2. We can get better at combining stuff into other stuff such that the new stuff makes us happier than what we had before. Think a recipe for chocolate chip cookies. On their own, flour, sugar, eggs, chocolate, butter and other ingredients are fine, but together they are amazing. Getting better at combing existing resources like this makes us richer.
The industrial revolution was an example of both 1 and 2. It was 1 because we got better at harnessing existing natural resources (coal, oil, wood, etc.), but it was also 2 because we created technology that allowed us to combine these resources in ways that made our lives better (steam engine, electricity, cotton gin, etc.). Thus, we created both more and (often, but not always) better stuff, which increased our wealth. | 74 | 58 |
CMV: Developing space infrastructure should be a higher priority than trying to colonize Mars | There seems to be a lot of romance around the idea of colonizing Mars and I hope that someday there is a Martian colony. But first we need better space infrastructure. That means more efficient ways to launch and reuse rockets like SpaceX is developing. More needs to be done to develop Earth orbit capabilities, and perhaps a Moon base to develop the the first off world manufacturing and intermediate base for exploring further out. We also need to develop the infrastructure that will enable us to start doing asteroid mining. That’s primarily so that we don’t need to launch as much material into orbit to build things in space. What do you think? | I work in the software development industry, and there is a recurring debate on this very issue.
On the one hand, new projects are sexy. They attract investors and customers. They have goals that are easy to define and market.
On the other hand, infrastructure projects can help the "sexy" projects move faster in the future. They provide a network of support that, in theory, should make all future goals cheaper and easier to achieve.
There is a hidden downside of infrastructure projects, however. First, humans aren't good at predicting the future. We often build infrastructure to address problems that never materialize. Second, we often build infrastructure and then discover that other technology has advanced in ways that render our infrastructure irrelevant.
In software development, as in space technology and most other pursuits, it is often most efficient to develop infrastructure *alongside* the sexy projects on an as-needed basis to ensure that no waste is produced. | 18 | 69 |
CMV: The logic behind banning Muslim immigrants doesn't make sense | I truly don't understand this logic at all.
So the statements made basically say that we need to ban all Muslims because some of them are dangerous criminals. Actually the same fears are made towards Mexican immigrants as well ("they are rapists...").
Ok, so it's been decided to group by both religion/race as well as just race. And the logic is that if group A has criminals in it, that group must then be banned.
Obviously though if we apply this logic universally, we need to ban all white christians, black people, asian people.... I think all we'd be left with is maybe buddhists and taoists probably? We'd have less than a million people living in the USA.
I've been waiting to hear Trump explain exactly why it's worse for a Mexican or Muslim to commit a crime over a different race or religion, but he hasn't spoken to this at all. Which is where I get completely confused. What's the logic here? There doesn't seem to be any sense to this at all.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[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)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | If you look at it from a practical point of view, you could argue the following.
1. Looking at terrorism in the United States in the first sixteen years of this century, islamic extremism has had a huge impact, with islamic terrorists committing both the largest terrorist attack and the largest mass shooting in recent history.
2. It is currently unknown - or, rather, fundamentally disputed - how many Muslims hold extremist views, but the global consensus seems to be that a significant minority hold extremist views but are unwilling to act on them. For example, they find homosexual activities to be morally repugnant and worthy of being criminalized, but they are unwilling to 'enact justice' personally.
3. Radicalization within Muslim communities tends to focus on 'activating' latent hatred of 'the other' which already existed. This makes Muslim communities much more vulnerable to the efforts of radicals than any other community.
4. So from a general security point of view, preventing Muslims from migrating to the United States entirely would take away a lot of the soil from which weeds will grow (although it is currently unknown how many or where they will emerge). | 14 | 17 |
Are you at greater risk of sunburn up on a mountain? | I remember being told that sunburns are more likely when you're up in the mountains because the air is thinner. And that's why Andean peoples wear wide brim hats most of the time. And I think my own experience matches that. I've burnt pretty quickly when up in mountainous terrain.
But I also know (believe) that UV is mostly blocked by the ozone layer. And the ozone layer goes from 33,000 feet to 165,000 feet. So even on top of Everest you're fully under it. So it shouldn't matter how high you walk. You should still be protected.
So what's going on? Which part of what I think I know is wrong?
| The ultraviolet spectrum is pretty broad (400 nm – 10 nm) and is divided into three sub-bands. Ozone is really good at absorbing the short UV-C wavelengths and moderately good at absorbing the medium UV-B wavelengths. UV-A and UV-B (which are responsible for sunburns and skin cancer) are mostly absorbed by water vapor and other atmospheric gases, which is why being at sealevel offers more protection than on a mountain. | 50 | 59 |
What effect did Chomsky have on philosophy? | His wikipedia has a lot of references to him being a philosopher and being a major figure of philosophy which is contrary to what I've read but I'm curious what effect he actually had on philosophy? | Chomsky's been pretty engaged with two important branches of contemporary philosophy: language and mind. His book, New Horizons In The Study Of Language And Mind lays out some key philosophical commitments, including methodological naturalism (belief that we can study L&M using the methods of the natural sciences) and semantic internalism (that there is no word-world relation like reference or denotation). His work has certainly influenced philosophers such as Fodor (a great deal in his case), Searle, Grice, (slightly obliquely and less neatly) Davidson.
I can add more if you have more questions. | 82 | 109 |
ELI5: Why do some traffic lights seem fast and responsive, while others leave you waiting for ages even when there's no other cars? | Are they configured differently depending on the location? | Some traffic lights are designed to detect the presence of cars. They use an inductive strip which runs current, and will respond differently if a car is on top of it because the strip will induce current in the car's chassis and body. They can thus detect that a car is present and adjust light timing accordingly.
Other lights are "dumb" and just switch based on a preset timer, so you will be stuck at them regardless of traffic flow. | 31 | 49 |
ELI5- Do animals have ways of keeping their teeth clean? Are they affected by the same dental problems that can occur in humans? | Animals have a variety of ways of maintaining oral health.
Some animals, like sharks, continuously grow new teeth and shed old ones. So if they chip or lose a tooth they just have to wait a few weeks for new ones to come in, then it's back to business as usual.
A lot of rodents and ungulates have a different solution of having teeth continuing to grow indefinitely. This has some drawbacks, primarily that if they don't wear down their teeth, the teeth can become overgrown and and even grow into the animal and hurt it. So maintenance is key.
Animals who don't have either of those benefits can do a variety of things, some chew on leaves, some form symbiotic relationships with smaller animals that pick bits of food out from between their teeth. But ultimately, without modern dental care, these animals will one day lose their teeth and be unable to feed. | 64 | 81 |
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ELI5: why are some guns more deadly than others? Is it something to do with the speed at which bullets come out, or the size of the bullet? Like why is a revolver taken to be a stronger weapon than a glock/pistol? | Oh dear, you're already getting a lot of terrible information, so let me help you out:
There's a lot of different factors that determine how "deadly" a firearm is. The most important is probably the type of round it fires. The keys to a deadly round are how much force it carries, and how effectively it transfers that force to the target.
There's two major factors in a firearm cartridge to consider: size of the bullet, and size of the casing. Bigger (wider/longer) bullets will obviously carry more force simply by virtue of having more mass. Longer casings will provide the bullet with more velocity because they hold more gunpowder. Generally speaking, a higher combination of mass and velocity is more deadly because it carries more force to the target. However, that only gets us part of the way there.
How that force is delivered also makes a difference. The goal of a bullet is not to simply penetrate a target, but to damage it. In this case, shape and composition of the bullet come into play. Rounds that have more solid bullets (such as full metal jacket) and/or more pointed ends are more likely to cleanly penetrate a target. Cleaner penetration means the shock will be concentrated to a smaller area. Also, if the bullet passes *through* the target, then some of its energy will not have been transferred.
Rounds that have flatter/softer tips, on the other hand (such as soft-point or hollow-point) will expand on impact, increasing the area in which the force is delivered in the body. This means force is delivered to a wider area, causing greater shock to the target. The expansion also decreases the likelihood that the bullet will escape the body, ensuring that *all* of its kinetic energy is transferred.
So, generally speaking, you want a heavy, fast (but not so fast that it over penetrates) round with a soft, expanding tip. Right? Well...maybe. Another important fact about firearms is that they are very situational. They are a form of tool, and there's a right tool for every job. While you might want a medium-velocity hollow-point round to shoot a regular target, what about someone behind cover? In that case, a more pointed round (such as a spitzer bullet) with a higher velocity would be better. What if you're shooting at very close range, possibly with poor visibility? You may not want a bullet at all, but rather a shell loaded with shot pellets.
As for the firearms themselves, it's also very situational. Most people would probably pick a modern automatic or semi-automatic rifle as "more/most deadly," but it depends on the use. If your target is very far away, you might hit them with a bolt-action rifle when your AR-15 can't even fire that far. If they are close, a shotgun would be more effective, while a rifle round would probably fly right through them. Infinite other questions also affect the answer. Is the target shooting at you? Are they wearing armor? What is the terrain/climate like? Is being immobile an option? Is the target aware of your presence?
An interesting example comes from the war in Afghanistan. The standard issue rifle for the US military is the AR-15 (M16). This has long been considered the modern gold standard for military rifles. However, in Afghanistan, Taliban fighters were using less fancy rifles, but with higher-power rounds. Due to the open terrain of the country, they could take up position far away and shoot at US soldiers, while the AR-15s didn't have the range to reach them back. The military then started re-issuing the M14. Although it's an outdated firearm (taken out of service in 1964), it fired a round that could travel the distance and properly engage the Taliban.
TL;DR: Mass + velocity are generally good, but otherwise everything is situational. | 121 | 33 |
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[Star Wars] Are AT-ATs practical troop transportation? Why or why not? | Like many things, it depends on the circumstances. AT-AT's are built, like much of the Empire's war machine, with intimidation in mind, as much as practicality. Simply as a troop delivery mechanism, there are certainly methods of moving troops faster or moving more of them to any given location. There's very little, however, than can take a heavier pounding than an AT-AT, and the sheer mental impact of several 20-meter tall monstrosities descending on a defended position shouldn't be underestimated. It has relatively heavy forward armament, and can deliver 40-50 armored troops.
Is it the MOST practical troop transport? No. It's not particularly fast compared to some, it has no armament anywhere but directly forward, and if they operate without air cover, they are vulnerable to damage or entanglement around the legs. When it comes to an assault, properly supported, they are pretty damn formidable, and add a hell of a punch against a entrenched position. | 49 | 40 |
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If God exists; why does he allow horrible things to happen to good people? | I’ve recently become interested in theodicy and I can’t find one argument for God that makes sense. I believe in life after death but I don’t know if I believe in God. I’m looking at horrible things happening in Ukraine and don’t understand why he allows these things to happen if he exists. Does anybody know of a more recent theodicy that is reputable? | Part of why the range of arguments in this field can, at times, feel so narrow is because the philosophy of religion still almost exclusively looks at a very particular conception of a particular god (the Abrahamic one). This is a single monotheistic god possessing omnipotence, omniscience, benevolence and other characteristics that bear upon issues of theodicy. But the Abrahamic religions only make up 57% of the world's population, and the god is rather unusual in its features when compared to most of the rest of the gods out there. As some examples:
Shendao, Shindo and Shinto (somewhere up to 12% of the Earth's population) believe in *shen/shin/kami* that are not omnipotent, and (usually) not omniscient. The *shen* do not have the power to stop what is happening in Ukraine, they only have the power to inspire humanity to find solutions.
Hinduism (15%) is a complex set of different traditions, but typically devas are none of those qualities of omnipotent, omniscient or benevolent, and typically they are mortal and subject to the same laws of the universe as we are. So the issue of theodicy does not normally arise at all. Devas in Buddhism (another 6%) are similar.
Daoism (a few %) conceptualizes 'good' and 'evil' in a different way, insofar that a harmonious and peaceful universe necessarily must contain both some of the things we call 'good' and 'evil'.
etc etc | 16 | 21 |
ELI5: If all bread is made from flour, water, and yeast, then how are there so many different varieties and textures of bread and how do they all taste different? Loaf, crusty baguette, chewy ciabatta, etc. | There are different types of flour and different types of yeast
The ingredients can be combined in different proportions.
Some breads use milk or egg.
The cooking temperatures or methods can vary.
Dough can be allowed to rise for different amounts of time or in different environments.
Sometimes, starters are used, meaning there is already a culture to be introduced to the raw ingredients.
I bet there's other stuff too lol | 19 | 15 |
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ELI5: Does a larger engine capacity (cc's or Ls) translate to a decreased fuel efficiency and larger fuel consumption rate? What other SIGNIFICANT factors are at play in terms of efficiency and consumption? | SO a friend of mine was telling me her vehicle burns quite a lot of gas because it has a [large engine](http://i.imgur.com/AS6pfpk.jpg).
I would like to know how the mechanics of engine size translates to fuel consumption and efficiency.
Common sense dictates that a larger engine burns more fuel during combustion, but how does that combustion cycle correlate to covering a fixed distance per cycle (for example... how far would one cycle of firing all cylinders make the vehicle travel once static friction is overcome? 20 feet?)
What other factors make a huge difference in performance? Tire pressure, oil levels etc?
I understand that when all cylinders are firing, a 3 L engine would consume more fuel than a 2 L engine with the same amount of pistons. I'm aware that vehicles are engineered differently so it would probably be foolish of me to ask at what stage does the engine decide to fire all cylinders instead of a fraction of them etc...
I'm asking this so that I can make a better informed decision in terms of fuel efficiency and fuel consumption when purchasing my first vehicle.
Sorry if it seems like I'm all over the place/incoherent in asking the question.
Thanks in advance for all your replies. | Internal combustion engines operate with a variable efficiency. At idle, all the energy is going to moving the car parts around, none is going to move the car forward. At high power output, lots of power is going to make the car move, but some is still used to just keep the parts moving around.
A large engine is less efficient at idle, because the parts are bigger, and there might be more of them. It might have a higher maximum power output, but that's not an aid to efficiency.
The other reason a large engine is less efficient is that it takes a minimum gasoline density for the spark to work. That means that there is a minimum fuel consumption needed to keep the car idling. The larger the displacement, the more air that needs that much fuel. | 13 | 15 |
ELI5: While early humans' migration led to changes in our skin tones, what affected the distinctive face characteristics of each race? | Over time, random changes happen in the DNA of any organism. These mutations can lead to different traits and they are passed to the children of the organism.
Evolutionary pressure is when one trait keeps the person alive better so they have a better chance to have children and pass on the trait.
Not all changes in facial features are because of evolutionary pressure. Some random changes just happen. Because the populations of different races were separated, the random changes that accumulated in each area would be different.
Also, perhaps, there came to be styles as there are styles in clothing or architecture. When people choose mates to have children with, perhaps they favored certain facial features over others. But this would not be necessary to explain variation between geographically separated groups.
The OP’s question comes from a faulty understanding of evolution. Not every trait is “because” that trait will “help” There’s no design and no designer. As long as the trait doesn’t cause harm, it doesn’t have to have a purpose. | 77 | 90 |
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Why don't drugs provoke an immune response? | The immune system recognizes and attacks foreign entities. So why doesn't it have a problem with (most) drugs? Is it because they are too small to be picked up the immune "radar"? | Medicinal chemist here.
Two things:
A full immune response is usually the body's response to biologics, not just random chemicals. The vast majority of marketed drugs are not biologics. There are certainly drugs that are biologics, though, so it's still a fair point of quandary.
The body does try to eliminate all foreign bodies, whether they're biologics or not. There's multiple areas of drug design that are dedicated to getting around this via either small changes to the chemical structure to combat digestion and enzymatic breakdown, clever formulation to assist with rapid transfer into the body... And most likely both of these things.
The drugs you see marketed usually don't have problems with immune response because they'd never see the light of day on the market of they did. Many drugs get pulled in clinical trials for adverse effects of various types, which is why you don't see them. | 71 | 40 |
Outside of choosing a minor what other options help get undergrad applicants into somewhat unrelated master's programs? | Sociology Undergrad student, Graduating spring of 2019, had a rocky start with an undiagnosed learning disability, doing stellar after treatment and discovery.
I'm more curious how I could get into Enviromental sciences or sustainability programs at the master's level as a current sociology student. | Get involved with research. Go find the faculty page for the department/field you're interested in moving toward. Read every professor's page, bio, CV, etc. Look for 1) topics that interest you, 2) topics related to your current undergraduate major, and preferably 3) topics that connect those two.
Reach out to these faculty by email. Brief bio that says you're interested in their research and would love to chat. Meet up with then and ask about their research, tell them what interests you. Tell them your goals and that your like to get involved with their research.
They'll likely suggest you take XYZ requisite courses to get an understanding of the field. Take them and ask about other things you can do in your free time. Hopefully, they'll eventually bring you on to an existing or new project. | 23 | 19 |
ELI5: What is exactly happening when we zone our eyes out and make everything blurry? | Your eyes have lenses that can adjust to focus on objects at different distances, exactly like a camera does. When you do this, you're setting your lenses to focus at a different distance than the object you're looking at. | 18 | 55 |
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ELI5: Since the ISS is moving so fast, does NASA need to account for doppler shift in the radio signal? How do they account for this considering the ISS uses FM? | NASA (and all communications with fast moving satellites) use Dynamic Doppler Compensation, where the frequency of the broadcasts are adjusted progressively through the broadcast to ensure that the receiver maintains a solid signal on the correct frequency. | 11 | 18 |
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Does water have a high heat capacity because it is a polar molecule? Do all polar molecules have high heat capacity? | The heat capacity of water is high because it has a great many numbers of *degrees of freedom*.
Water is a bent molecule. That means it has 9 *possible* degrees of freedom: 3 translation degrees (x,y,z), 3 vibration degrees, and 3 rotation degrees. Moreover, because water is also a polar molecule, and because individual water molecules are capable of interacting with each other via hydrogen bonds, these 9 degrees of freedom are relevant because the water molecules are capable of transferring energy between each other and into those 9 degrees of freedom.
Additionally, and this is what makes water really special, all 9 of those degrees of freedom correspond, on a quantum level, to relevant energies that you'll encounter at STP. That is to say, there are degrees of freedom that are actually relevant at the temperatures (energies) we're actually interested in! If you were to take, say, H_*2*_, which is a straight (not bent) diatomic gas, you find at the quantum level that yes, strictly speaking it may have three degrees of rotational freedom, but the rotation *along* the axis - spinning like a drill - is not relevant because the energy levels are so huge that it's not possible to transfer energy into that degree. It turns out, that in water all 9 of those degrees correspond to energies you're likely to find at STP.
If you calculate out the thermodynamic temperature of water:
> T = 1 / (δS/δE)
...you find more degrees of freedom mean that the entropy (S) increases much more for water given an infinitesimal of energy. A hand-waving, back-of-the-envelope explanation would be to say that there are more energy sinks available to absorb thermal energy before the temperature increases.
Now on top of all that, all those degrees of freedom also happen to be attached to a very "light" molecule. Sure you can find more degrees of freedom in some polymer, with hundreds of atoms in a chain, but those damn things weigh a ton, and every atom you add to the molecule just increases it's molar mass, which renders intermolecular forces like hydrogen bonding less relevant while at the same time reducing C_*M*_ by increasing said mass. As for C_*V*_, water also does a hell of a job keeping it's volume pretty low by existing in a liquid state at much higher temperatures than what one would expect for exactly those reasons: The (relevant) intermolecular forces.
Water is just about the lightest compound one can think of that combines all these properties. | 40 | 78 |
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Eli5: why are mice the preferred "testing" subjects in scientific experiments? | They are the right combination of breeding quickly, maturing quickly, being easy to care for, being easy to handle, and being close enough to humans to get meaningful results.
We might get slightly more analogous results testing with gorillas, but a 400 pound animal that takes 15 years to mature, has one offspring a year, and that can rip you head off isn't worth it. | 142 | 85 |
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ELI5: How is it that scientists were able to completely eradicate smallpox, but they cant do that with other diseases? | There's several factors:
Smallpox only had a couple of strains to worry about and the vaccine worked against both.
The vaccine was cheap and really easy to produce.
The vaccine itself was infectious, which helped spread immunity.
Smallpox is such a nasty disease that many countries already had vaccination programmes or even compulsory vaccination, making it easier for so many countries to agree to the massive eradication effort.
The fact that there aren't really any other diseases which have pushed us to such effort is probably a good thing! | 42 | 33 |
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ELI5: If water is wet, how does hot water dry out your skin? | While the explanation would involve skin oils, does this apply to cold water too? | Your skin is protected by a layer of oil that you produce. When you wash the skin, especially with hot soapy water you remove this protective layer or oil. This then allows your skin to dry out more easily than if the protective layer was there. | 127 | 176 |
ELI5: Software patents and why they are "evil" | I'm not quite sure what a software patent is, and Wikipedia doesn't have the greatest information.
Is it like the creation of a file type that others cannot use (.rar where only winRAR can make but others can unarchive)?
Or is it like a process (the way VLC opens a video file)?
| A computer program is a series of instructions, like a recipe.
Suppose you're making dinner, and decide to mix certain spices together in a bowl then toast them in a pan.
It turns out well, so you publish it as part of a recipe.
Then someone comes along and sues you, saying they invented the idea of mixing those spices together and toasting them. You protest that you didn't copy them, it was your own idea. That doesn't matter. The other guy thought of it first, and now he owns that technique for the next nineteen years. He can charge you whatever royalties he likes, or prevent you from using that technique at all.
Software patents are like that. Patents are awarded for the sort of ideas that programmers come up with all the time, as part of their everyday work.
Getting a software patent is a lot more expensive than coming up with the "invention" in the first place, so only large corporations can afford to do it much. | 22 | 46 |
How is the right amino acid brought to ribosomes? | So what I know is that the mRNA is brought to the ribosome with a code for an amino acid. I also know that the tRNA with a matching codon and correct amino acid are brought to the ribosome for assembly. But how is the right amino known? Does the ribosome read the mRNA and call for a tRNA or do the tRNA keep trying to fit the codon in the ribosome till it fits then goes and brings the amino acid. Thanks i have a test on this is a couple of hours. | > But how is the right amino known?
Put simply, it doesn't 'know'. All the amino acids are attached to tRNAs and they all diffuse around until they meet a ribosome that requires that particular one, as determined by the codon of the mRNA. It can't "call for it" it just waits for it. | 13 | 59 |
Are humans getting taller? | I’ve read that Americans, on average, have stayed the same height for the past 50 years. Is this true even now with the amount of immigration from Latin America and Asia where people tend to be shorter on average? Are millennials taller than their parents? Has the age at which we stop growing decreased making young children of this generation taller than the previous generation? | In general, living conditions would be a bigger factor than genetics as how tall people get within the specified time period (50 years). It is said that North Koreans are, on average, three inches shorter than South Koreans due to poor living conditions in the North.
Things like better nutrition, better healthcare and lack of corporeal punishment on women and children with sticks thinner than your thumb all lead to taller people. | 144 | 199 |
Why are programming concepts explained with such difficult language? | I just read a page explaining concurrency programming because it seems to be a hot topic in west coast tech area interviews this month.
I did not understand half of the concepts it was trying to convey because the language was to foreign and generic. I finally understood that I already used concurrency in a script that leverages threads for api calls because the network communication was the bottleneck. (Processing won't hault just because one thread is waiting for a reply).
I had to reread the article after I understood that I already did this once to even get near to fully grasping what the author was trying to convey.
Is this intentional? MSDN docs are the fucking worst as well. I can't help but feel like these authors are trying to jack themselves off or gate their knowledge by forcing readers to speak their weird language.
What am I missing here? | There is very specific language when referring to concepts, because there are so many concepts. It's ironically to prevent confusion and misinformation, by not using language applicable to multiple other concepts.
The field as a whole needs more ELI5. | 93 | 66 |
[ELI5]: How do antivirus apps work? What are the looking for when they “scan” our files? | There are two primary methods for virus detection: signature-based and heuristics-based.
A signature-based antivirus program looks at the files on your system and calculates a specific value based on the file's contents. It has a list of values that it knows correspond to viruses and other malware; if it sees one of them pop up on your machine, it knows to delete it. These definitions are updated often, and are very good for detecting and cleaning known threats. Not so good for code that changes, or new threats. Which leads us to...
Heuristics. It's a fancy word for a simple concept, and what it boils down to is that your antivirus program will simulate the effects of unknown code in its own private sandbox, and watches the commands as they run. If it looks like a virus, the program will flag it.
Advantages: not reliant on signature lists, can detect new variants of old viruses.
Disadvantages: can be slower, can generate false positives. | 21 | 19 |
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ELI5: Why doesn’t GPS work underwater? | If a satellite can pinpoint my location from SPACE, how come a (relatively) small amount of water prevents GPS from working? | Water absorbs radio waves across a considerable band of wavelengths.
It's so good at this that your microwave oven can quickly boil water by pelting it with radio.
Since the GPS is relying on radio communication to triangulate itself, it will lose contact quickly under water. | 66 | 30 |
Eli5 Why do military units carry the same formation through history such as the 450 year old 2nd dragoon regiment in France. | History and tradition is a big thing in the military of many nations. It generates a sense of "belonging" that the current personnel are the inheritors of a line of battle honours dating back through the years. Maintaining that tradition is a big motivating factor for new recruits. | 41 | 29 |
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ELI5: If all wavelengths of light travel at the same speed, what causes them to rainbow after exiting a glass prism? | A prism causes light to refract, which is described by the *refractive index* of the material. The refractive index is different for different waves of light, so that rays of different wave-lengths get refracted at different angles. White light, made up of many wave-lengths, is split up by the refraction and each colored ray will be cast in a slightly different place from the others. That's what produces the spectrum. | 12 | 16 |
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