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Tuesday, February 21, 2017

Why are we colder when wet?

Why are we colder when wet?


Why are we colder when wet?

Posted: 21 Feb 2017 04:36 AM PST

Do microwaves kill bacteria?

Posted: 20 Feb 2017 09:51 AM PST

I've always wondered if a microwave oven could be used as a disinfectant. Does it kill bacteria outright? Or is it the created heat in food/other elements that does the trick?

submitted by /u/Bdoggy10
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Did the introduction of antidepressants have any effect on suicide rates?

Posted: 20 Feb 2017 09:57 PM PST

If a stalactite or stalagmite were constantly exposed to air currents as they formed, would they grow in a slanted or curved direction?

Posted: 21 Feb 2017 04:37 AM PST

Is there a material that can change permeability based on electric charge?

Posted: 21 Feb 2017 07:00 AM PST

Imagine a membrane or valve that could open or close by introducing a current, changing polarity.

Is there anything like this? Or being developed?

submitted by /u/castles_of_beer
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How do birds maintain spatial orientation in clouds?

Posted: 20 Feb 2017 07:36 PM PST

Human experience in aviation has firmly cemented that trusting your vestibular system for orientation without reference to a horizon is impossible. The rate of error accumulation in your inner ear is rapid and results in aircraft in dangerous attitudes which pilots may not recognize if they do not have an artificial horizon (FAA Reference).

My question is - do birds have similar trouble? How to do they maintain orientation in a cloud if they do not have a reference to the horizon? If they lose orientation, how would they regain it?

Finally, and mostly out of curiosity, what are the limits of the environment that birds fly in? Will they fly into extreme up/downdrafts? Mountain wave? Icing conditions?

submitted by /u/MOX-News
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What does it mean that if you pull quarks apart, the energy required to do that creates more quarks beside each so there is never a lone quark?

Posted: 21 Feb 2017 06:16 AM PST

Unlike the attraction of magnets or planets, quarks are attracted more the farther apart they get, at least when they're very close.

Does it mean quarks are virtual particles (only representing vectors)?

Does it mean space is an incompressible fluid of quarks where the "empty space" is made of some neutral combination of quarks?

submitted by /u/BenRayfield
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If liquid helium becomes too scarce and expensive, is there another substance that MRI machines can use for cooling?

Posted: 21 Feb 2017 07:14 AM PST

What is really happening in this natural phenomenon?

Posted: 21 Feb 2017 03:26 AM PST

Photos of the phenomenon Credit to Kjell H. Sæther for the photos. They were taken the night before February 20th 2017 in Karasjok, Norway.

I've been told that this happens only when there's no wind, very cold (-25 celsius at the time) and has something to do with ice particles in the air. I assume the ice particles reflect the lights, but why does the light seem to form pillars?

submitted by /u/Fuccaneer
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How quickly does a diluted solution homogenize?

Posted: 21 Feb 2017 04:48 AM PST

If I dissolve a compound in a solution of water and then were to dilute that solution, how quickly does the dissolved compound disperse evenly throughout the entire volume?

Does the compound being dissolved play a role in the time it takes to homogenize?

Does the concentration of the dissolved compound play a role in the time it takes to homogenize?

In particular I am noticing a strange phenomenon when dissolving sodium lauryl sulfate in water and then diluting it with more water. Next adding Caltaine C-35, followed by glycerine once it appears everything has dissolved. After adding fragrance to this mix the final sometimes turns out the have the consistency of slime and then sometimes has the consistency of water. The amount of each compound is the same as well as the temperature each time. The only difference I can find is that when allowing the SLS a decent amount of time to mix and then allowing the C-35 a decent amount of time that the solution comes out with the consistency of water every time.

submitted by /u/lxBATESxl
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How come moon's soil is rich in helium-3 when it has a very low escape velocity?

Posted: 20 Feb 2017 10:35 PM PST

Can a function that is identically 0 for x>a have a continuous derivative everywhere if for some x0 < a f(x0) > 0, f'(x0) < 0?

Posted: 20 Feb 2017 06:35 PM PST

Asking this in the context of possible wavefunctions in a potential well. If a function goes to zero at some finite value but is nonzero before it, can its derivative be continuous across that interchange? It seems to me like there must be a cusp at x = a, but my real analysis background is too limited to verify this.

submitted by /u/LorathiHenchman
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What is the main source of protein for large herbivores?

Posted: 20 Feb 2017 04:21 PM PST

Where does the protein needed by animals like horses or cows come from in the wild, other than the milk they had when they were still young? Do they get everything they need just from grass and some grains? If they do, wouldn't they need to eat way more than their own weight every single day, due to the small quantities of fats and protein grass has?

submitted by /u/cocodecabra
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Is the sun (and any large body) surrounded by a layer of dark matter?

Posted: 21 Feb 2017 12:32 AM PST

I was listening to the Infinite Monkey Cage yesterday and they were saying that dark matter doesn't interact with normal matter in any way, except gravitationally. Does this mean that you could have huge, thick layers of dark matter orbiting stars and planets, but we just wouldn't be able to tell because we can't detect them?

submitted by /u/MrGoerge
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With an aerodynamic shape, suitably powerful engines and a proportianate wingspan, could an aircraft of immense size still fly? Like, say, one the length and width of an average aircraft carrier?

Posted: 20 Feb 2017 03:40 PM PST

How do we collect information about children's thoughts before they can speak?

Posted: 20 Feb 2017 09:10 PM PST

Specifically, this question comes from me reading a Sociology textbook, in a portion talking on self-identity that says "Children do not grasp concepts such as 'I', 'me', and 'you' until age two or later." How would we collect information on this idea, and how can we infer that the information is definitively indicative to the absence of a child's understanding of self?

submitted by /u/dextrousfuckery
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Would it have been possible to watch the moon landings on earth?

Posted: 20 Feb 2017 05:33 PM PST

Is there a powerful enough telescope that would allow a person here on earth to view the moon landings clearly? If so, is there anyone that that is known to have done it?

submitted by /u/HarambeIsGOAT
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Does Earth's water escape into space? If so, will the planet eventually run out of water?

Posted: 20 Feb 2017 05:05 PM PST

How Geologist do calculate the elevation of terrain?

Posted: 20 Feb 2017 08:43 PM PST

Why does melting ice caps mean rising sea level?

Posted: 21 Feb 2017 04:04 AM PST

When you drop some ice in water, mark the water level, wait for it to melt, the water level will stay the same, but why will the polar caps be any different? Shouldn't the sea level stay the same like the glass and the ice cube? I hope I explained my question well and thanks in advance!

submitted by /u/sm9u
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If it were possible for a star the size of a basketball to exist, how much energy would it produce, and how long would it take for it to expend all of it's hydrogen?

Posted: 20 Feb 2017 10:38 PM PST

I have been googling around and haven't been able to find any answers to this question, so I was wondering if it would be possible to calculate the answer to this question, based on our current understanding of how fusion works?

submitted by /u/Damadawf
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Photons are continuously exchanged between electric charges - What is the source of this energy?

Posted: 20 Feb 2017 08:22 PM PST

According to the Standard Model of particle physics (from what I understand), electric charge is mediated by photons. This means that the attraction/repulsion you feel between magnets is caused by photons continuously exchanged between the two materials. Where is that energy coming from??

Is it the "spin" of each electron? If so, what is powering the non-stop continuous spin of each electron? The electron's interaction with the Higgs field?

submitted by /u/uncertaintyprincipia
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If the Higgs mechanism explains how things have the property of mass, are similar mechanism needed to explain properties like electric charge?

Posted: 20 Feb 2017 11:57 AM PST

Monday, February 20, 2017

Are there ocean deserts? Are there parts of the ocean that never or rarely receive rain?

Are there ocean deserts? Are there parts of the ocean that never or rarely receive rain?


Are there ocean deserts? Are there parts of the ocean that never or rarely receive rain?

Posted: 19 Feb 2017 04:18 PM PST

Can Nuclear Reactors Become More Fuel Efficient?

Posted: 20 Feb 2017 06:56 AM PST

I'm trying to gauge whether demand for uranium will increase in a more or less linear manner with an increase of the number of reactors (and demand for energy), or whether technological advances in reactor design could result in greater fuel efficiency and therefore steady or even declining demand for uranium even as more reactors come online.

So, is the amount of energy released directly linked to the amount of fuel present, or is it possible to do more with less?

Thanks for any replies!

submitted by /u/DapperDarington
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[Experiment] Which method would get the boiled water to lower temperature within the same amount of time?

Posted: 20 Feb 2017 01:23 AM PST

You have two cups half full with boiled water.

  1. In one cup, let's call it cup "A", you fill the other half with cold water straight away and wait 10 min.

  2. In the other cup, let's call it cup "B", you wait 5 min before you fill the other half with cold water, then wait another 5 min.

  3. In which cup the water's temperature will be lower in the end of the 10 min?

*Assuming all the variables are the same in both of the methods. In example, same water's starting temperature, cup's size and material, etc.

Apologizes for the English, it's not my native language.

submitted by /u/gimel182
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Can something be in a superposition between existing and not existing?

Posted: 19 Feb 2017 11:50 PM PST

I know that with quantum superposition that something can exist in two different places at the same time, but can something be in a super position between existing and not existing? and how would that work?

submitted by /u/PopularPlanet
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What kind of research has been done for reliable long range communications?

Posted: 20 Feb 2017 03:30 AM PST

I've wondered about this a few times while watching movies where they are sending communications that will take hours, days or even years to reach the destination. Is there any kind of protocol out there for reliable transfer of data over extremely long distances where the standard syn/ack process isn't feasible?

If you're transferring to Mars you've got something like 11+ 3-21 minutes just to get there so sending back saying "we missed a packet" isn't really an easy way to do it. If you're transferring something that critically needs to be intact when it arrives like say a software patch, then corruption in transmission isn't something you want to be dealing with.

So my thought was something like you end up sending your data 2-3 times with interspersed checksums of sections of the package to allow verification and the ability to rebuild corrupted packets at the other end. I mean this is only from a few minutes of thinking about it and not a ton of knowledge of how the transfers would be done or how the rebuilding could be done.

I know that with newsfeeds there is some ability to rebuild damaged packages when they arrive. I don't know how that is done so that might be reliant on the source server to just rebuild without having to completely re-download.

Unfortunately googling about this doesn't bring up much since the results are generally inundated with "I'm in Australia, why is my game so slow" kind of questions.

submitted by /u/Verneff
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How do you calculate the coefficients of a polynomial regression?

Posted: 20 Feb 2017 02:00 AM PST

I'm currently writing a java program that outputs an array of the coefficients for a polynomial regression. For example for a linear regression:

$\hat{y} = b_{0} + b_{1}\hat{x} $ 

I would take a data set and calculate $b{0}$ and $b{1}$. This is simple to do for a linear equation.

$$b_{1} = \frac{SD_{x}}{SD_{y}}\cdot \frac{\sum \frac{x_{i} - \bar{x}}{SD_{x}} \cdot \frac{y_{i} - \bar{y}}{SD_{y}} }{n-1}$$ 

I'm having difficulty understanding what to do for nth polynomial regressions however. Can someone give me a simple explanation for how to calculate the coefficients for a polynomial regression?

submitted by /u/BainCapitalist
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Is the charge of an electron an average?

Posted: 19 Feb 2017 07:17 PM PST

I know that the accepted value for the charge of an electron is 1.602e-19 C, but is this value the same for all electrons?

submitted by /u/Man_Thighs
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Does microwaving food really destroy nutrients?

Posted: 19 Feb 2017 11:19 PM PST

My mother always told me not to microwave food because it killed all the good nutrients. But if a microwave produces non-ionizing radiation, then is anything really being destroyed?

submitted by /u/blake_williamss
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Why is it so difficult for particle accelerators to increase in energy, seeing as you need about 10000000 Tev for ~one Joule?

Posted: 19 Feb 2017 08:14 AM PST

Couldn't we just pour an amount of energy measured in joules in, and see what happens?

submitted by /u/TimAnEnchanter
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Are there ocean dead zones where there is little or no life activity? If so why do they exist?

Posted: 20 Feb 2017 12:32 AM PST

Why is there a need for bigger particle accelerators? If we need to accelerate a particle to a higher speed, can't we just make it go several laps?

Posted: 20 Feb 2017 12:32 AM PST

What are the dangers of Particle Accelarators?

Posted: 20 Feb 2017 03:06 AM PST

Yesterday I went to a museum exhibition on the Large Hadron Collider, and I am interested to know if there are any dangers/cons with a particle accelerator other than of course the price. I understand there was some controversy with Stephen Hawking saying the God Particle could destroy the universe? Is this referring to the Higgs Boson discovered in 2012? Why could it destroy the universe? I am writing my high school assignment on particle accelerators, and one of the criteria is to assess the pros and cons of using them (most people for the assignment are doing Nuclear power plants or Medicine, so instead I decided to do something more interesting).

submitted by /u/UntameableBadass
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Why not send a drone to Mars that can recharge with solar panels?

Posted: 19 Feb 2017 10:43 PM PST

Since the Martian atmosphere is 0.6% of Earth's air density, the propellers will have to generate 166.6 times more thrust. However, since gravity is only 38% of Earth, 166.6 x 0.38 = 63.3 times more thrust. Why not increase the size of the propellers 8 fold? This will create 64 times the surface area and 64 times the thrust. Spinning huge propellers shouldn't be a problem because they won't face much air resistance.

submitted by /u/bryceguy72
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Does elevation change affect birds the same way it affects humans? (Or any other land animal for that matter)

Posted: 19 Feb 2017 03:14 PM PST

What is the inner and outer horizon on a black hole?

Posted: 19 Feb 2017 09:56 AM PST

My question originates from this sentence on the Wikipedia page about the black hole in S5 0014+81:

"The Schwarzschild radius of this black hole is 118.35 billion kilometers. So, this black hole has an external horizon showing a diameter of 236.7 billion kilometers"

I thought that the event horizon is formed at the Schwarzschild radius of an object. I have seen diagrams of Kerr black holes displaying an inner and outer horizon but I do not understand what that means.

submitted by /u/ev3nth0rizon
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What is the speed of light moving relative to?

Posted: 19 Feb 2017 08:00 PM PST

My longer question is this:

If, for example, a planet launches a spaceship in the direction of their momentum that is going the planet's speed +1/10th the speed of light... then the ship launches a shuttle in the same direction that is going the planet's speed + the ship's speed +1/10th the speed of light. After 10 iterations, would the last object be going the speed of light relative to the planet?

Or am I completely misunderstanding physics?

submitted by /u/seemslucky
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If global warming is occurring, why haven't the sea levels risen?

Posted: 20 Feb 2017 03:12 AM PST

Not a climate change denier, just genuinely curious.

submitted by /u/All_thingsConsidered
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According to a recent study, oxygen levels in the ocean show signs of decreasing, around 2% less. Predictions for the end of the century were 7% less. What would happen to sea life in that scenario?

Posted: 19 Feb 2017 04:10 PM PST

Also, what RCP are they basing that study off of?

submitted by /u/shreditorOG
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Is it possible to seed the clouds so that the heavy rains that are causing problems in California release their water over the Pacific Ocean before reaching land?

Posted: 19 Feb 2017 06:21 PM PST

I'm referring to the story in the link below where the "atmospheric river" looks narrow enough to focus your cloud seeding efforts on.

http://mashable.com/2017/02/17/atmospheric-river-california-storm-flooding/?utm_cid=hp-h-33#ynQeRjpVJOqO

submitted by /u/tomg288374
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How does underwater pressure work in a cave system?

Posted: 19 Feb 2017 02:06 PM PST

If you're in an cave system on the ocean floor, is the pressure the same in said cave as outside at the same depth of any given point of the cave? Or more? Or less?

submitted by /u/Deltair114
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[Physics] Is there zero point energy in liquids?

Posted: 19 Feb 2017 03:32 PM PST

Do liquids have bulk vibrational states like phonons in solids?

submitted by /u/bearsnchairs
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What determines the top speed of an electric car, besides software limits?

Posted: 19 Feb 2017 06:36 PM PST

Related question: what about the max RPM of an electric motor not attached to a car?

My understanding is that an electric motor can spin as fast as you can alternate the current, until some kind of counteracting force becomes too strong or the motor destroys itself.

submitted by /u/SirNanigans
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Sunday, February 19, 2017

What is unique about carbon that makes it ideal for organic chemistry?

What is unique about carbon that makes it ideal for organic chemistry?


What is unique about carbon that makes it ideal for organic chemistry?

Posted: 18 Feb 2017 11:27 PM PST

I understand that it bonds well molecularly with many other elements. What other elements could be the basis for advanced life (I've heard silicon might be suitable)? What qualities in an element might make it reasonably suitable?

submitted by /u/Anticipator1234
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Could the conditions for life be different than ours in another part of the universe?

Posted: 18 Feb 2017 10:52 AM PST

Basically, can other life forms in the universe exist without our specific standards of living. Is it possible for life forms to exist not dependant on water or oxygen? Why is our standard for looking for life on other planets if there is water on those planets or not?

submitted by /u/spicyitallian
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When an engine is overloaded and can't pull the load, what happens inside the cylinders?

Posted: 19 Feb 2017 04:46 AM PST

Do the explosions still keep happening?

submitted by /u/20j2015
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Would the gravity on the moon closest to the earth be greater than the gravity on the opposite side?

Posted: 18 Feb 2017 08:55 PM PST

Was just thinking about this when i was looking at the moon and thinking about the gravity present on it

submitted by /u/K1ckerCS
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What evolutionary pressure is there for people with good looking faces?

Posted: 19 Feb 2017 07:00 AM PST

Why are some faces considered attractive? Why are people with certain faces more likely to survive?

submitted by /u/throwAwayObama
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How can you derive the positions of the heavy atoms in protein crystallography?

Posted: 19 Feb 2017 04:32 AM PST

Also, how can you deduce phase information for the structure factors of the native protein data set FP? Assuming you have a native protein data set (FP) and two different derivative data sets (FPH1 and FPH2).

I was trying to use a Harker construction to understand these questions but still struggling

submitted by /u/Abster_P
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Why does light need to consist of particles to explain the photo effect?

Posted: 18 Feb 2017 10:43 AM PST

Does Foucault's pendulum demonstrate that the earth is spherical or merely that it rotates?

Posted: 18 Feb 2017 10:16 AM PST

What is known about neurological/psychological differences between genders in cultures not using a binary gender system?

Posted: 18 Feb 2017 09:39 AM PST

Since there's some neurological and psychological sexual dimorphism in humans I was wondering to what extent the differences are due to culture. I've only seen studies comparing male/female/intersex in western or westernised cultures using a european gender system.

Are the differences in personality traits, aggression, types of intelligence, brain structure, hormones and such seen in the same way in other cultures? Do they vary based on sex alone or also gender? Is it too difficult to study due to the influence of western cultures?

submitted by /u/wondawfully
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Can high levels of stress or anxiety stop, delay, or otherwise affect menstruation?

Posted: 18 Feb 2017 07:16 PM PST

In a car, Is HP linear?

Posted: 18 Feb 2017 06:33 PM PST

This is something that has confused me for a while now. Is a 200HP car twice as powerful as a 100HP car. (All other variable taken out of course). Is it scalable? Can I say that a 200HP car twice as powerful, or is it scaled?

submitted by /u/The_Lord_Of_Mints
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How exactly do hormone treatments raise/lower a man's/woman's vocal pitch?

Posted: 18 Feb 2017 12:41 PM PST

[Chemistry] how does a medicine, like Mucinex DM, have a cough suppressant and an expectorant not cancel each other out?

Posted: 18 Feb 2017 05:36 PM PST

Taking it right now (few days) and not coughing so how is the expectorant supposed to work. How do they not cancel each other out as they are opposites?

submitted by /u/Ecjg2010
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Does a solar panel violate Ohm's law due to its non linear I-V curve?

Posted: 18 Feb 2017 02:18 PM PST

Ohm's law states that U=IR, but solar panels and triboelectric generators, for example, show a non-linear relationship, as found in the link http://myelectrical.com/Portals/0/SunBlogNuke/2/WindowsLiveWriter/PhotovoltaicPVElectricalCalculations_BD16/Image53.png

Is it a semi-conductor thing, given that diodes have similarly non-linear IV curves? I have thought of parasitic effects, but I do not believe they'd be as significant.

submitted by /u/GigaQubit
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Are organ transplants from close family less likely to be rejected?

Posted: 18 Feb 2017 06:59 PM PST

I'm wondering if being closely related (and as such more genetically similar) to an organ donor would have any effect on if an organ would be rejected.

submitted by /u/fynewis
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Can you create a machine learning algorithm to create a computer virus?

Posted: 18 Feb 2017 07:32 AM PST

So I have seen a lot of machine learning videos, including This one about Mario, This one about discerning instruments, This one about language, and this series on evolution simulators. Then, I also saw this xkcd. It made me think about since there are so many ways to produce machine learning algorithms in so many disparate fields and to do so many things, could you have an xkcd style virus-farm and try to use machine learning to look for security holes? The MarI/O simulator found a glitch in Mario, on this video and timestamp so it might not be too far a jump to consider that a really advanced neural network might be able to evolve a way to hack computer systems? If so how would it work?

Note: This is purely hypothetical. I just thought it would be an interesting idea.

submitted by /u/syryquil
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What is the proper derivation of Wien's approximation?

Posted: 18 Feb 2017 11:16 AM PST

I haven't seen anywhere on the internet a proper derivation of the Wien approximation, all of them try to derive it from Planck's law. Anyone can give me a detailed derivation, preferable also showing the law as it appears in Planck's paper ( u(lambda,T)=T5f(lambdaT) )?

submitted by /u/isnar000
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Why does drying seeds change their nutritional value so much?

Posted: 17 Feb 2017 11:20 PM PST

For example:

Fresh Pumpkin seeds have 54g of Carbohydrate and 19g of Fat, but dried seeds have 11g of Carbohydrate and 49g of Fat. (Google)

I would have thought drying means just removing water, and also that removing water would not cause this. Please explain.

submitted by /u/RLJ05
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