Archived threads in /sci/ - Science & Math - 462. page
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If the fundamental bits of energy in the universe (those "vibrating strings") are non-divisible and thus homogeneous how it is that they are understood to vibrate differently from one another? How is such a difference brought about?
>>7779112
bump
>>7779112
The picture of a vibrating string is better suited as just an analogy when dealing with the quantum mechanical behavior.
I will try to show what is going on with a toy model, bosonic string theory.
So what we mean by the vibrating is the different levels of energy excitations of the string states.
So if we take a look at closed string world sheet model, we describe the string by functions which embedded the worldsheet into the background spacetime.
[math] {X_R}^\mu \left( {\sigma ,\tau...
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>>7779657
** Fixed code lines:
[math] a_n^{\mu \dagger } = \frac{1}{{\sqrt n }}\alpha _{ - n}^\mu [/math]
and
[math] \left| S \right\rangle = a_{{n_1}}^{{\mu _1}\dagger }...a_{{n_m}}^{{\mu _m}\dagger}\left| 0 \right\rangle [/math]
How does one get a good understanding of preprocessing data before starting to think about neural network architecture, etc?
Is there a checklist or something? I guess there's imputation if needed, converting categorical to numerical, then... I look for correlations (correlation matrix) and maybe for mutual information (to check for non-linear correlations) but what else? I don't know, is there a complete guide for this?
Also, computer science general
>http://blog.kaggle.com/2016/01/04/how-much-did-it-rain-ii-winners-interview-1st-place-pupa-aka-aaron-sim/
>mfw random physics guy jumps into ML and gets #1
>>7779060
fuck NNs, bayesian program learning BTFO deep learning: http://science.sciencemag.org/content/350/6266/1332.full
>>7779090
nice paywall kike
is this a theory or it is actually true ?
it would be impossible for a human to trace a sun that far
>>7778929
Why don't you fucking look it up and do some basic research.
You don't even know what the word theory means in reference to science.
>>7778941
its all bullshit & you know it
What do you think of Guarana? Is this healthy on longterm use? is it more healthy than coffee?
>>7778921
Appears to be healthy, but no more healthy than coffee. Don't believe any "health food" claims.
>>7778921
>organic
>>7778921
I dont get nasty side effects I get from coffe, but since it's a stimulant I'm concerned about my heart anyway
Well /sci/? Is this person's baby's underwear going to melt?
>>7778917
Yes, and it will corrode the drain, as well.
>>7779003
And the baby
Very yes.
>>7779003
NaOH is benign to uncorroded steel, seemingly.
For about seven years now my heart will randomly go up in bpm for a while, and then it randomly stops and goes back down to the regular beat. In this time my chest will hurt, and I'll get weak or dizzy, and sometimes even lose sight for a few seconds. The reason I'm recently concerned is because it not only happened again, but for the past couple weeks my chest will randomly hurt, specifically around the left / heart region. What do you think is wrong with me? I'm going to get a blood test and telling the doctor what's wrong with me, but I'd like to...
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Forgot to mention, it only happens once or twice a year.
>>7778870
only? Lucky you
I have regular panic attacks and I thought my heart would stop quite a few times.
>>7778875
That sucks :(
I've read about quantum nonlocality and a little on Bell's Theorem, but there's something I don't quite understand.
So let's say two entangled particles are created and moved to either side of the universe. The idea is that you look at one and you immediately know the state of the other, and information about the other particle has travelled to you instantaneously.
Couldn't that just mean that the state of a particle contains more information that just that state? E.g. say you measure the state of one of the particles as being spin...
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>>7778814
its just mathematical fairytale bullshit with no practical application whatsoever
>>7778814
It's not defined before you measure it. But if you do measure it, it's instantaneously defined for both particles.
For this to have meaning one needs to know the state of a lot of particles, thats a pretty big computer one would need.
what does it still take to go all wireless economically and scientifically?
What do you mean by "go all wireless?"
>>7778754
More frequencies which reliably transmit through atmosphere and do not irradiate life.
Given the limits of resolution our amount of wireless bandwidth is basically finite, but our demand seems to be limitless. Thus we need to stop trying to go all wireless and and learn to better use the wireless we do have.
High density short range nodes do offer some promise, but they are still limited by the the same mechanism, not to mention the supporting infrastructure which already consumes a huge amount of resources...
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I'm completely lost after seeing this video https://youtu.be/AAmqeHCFq_8 (starts at 6:50) and reading some more about this topic.
What I understand so far is that energy is NOT stored in chemical bonds (even though most textbooks say it is). But where is the energy stored then and in what form? And how does it work? I'm a biochemistry undergraduate trying to understand this, but I can't get my head around it.
pls help
>>7778650
Well that was retarded. Im not entirely sure what he was trying to get, but I think its that the "energy in a chemical bond" is actually potential energy, like when you raise a ball some night off the ground it would be improper to say that the ball has energy or that the ball stores energy.
I've got to say if that is what he's saying then its one of the more autistic gripes I've seen, worse still since he didn't express what he was trying to say that well.
Ss he said. Energy was needed to produce a more complicated structure. Every part of the molceule trys to get to a more stable, ledd energy dense state.
Same like cole or oil. Energy has been transfered into it by pressure over long periods of time. If you burn it this energy is released since the molecul gets split into lower molecules and the energy that was used to bond it together is set free.
Don't listen to him, that guy is autistic and his rambling doesn't make any sense. Look at the other guy with the glasses, he doesn't really understand what that faggot's problem is, either
/Physics/ general
Post your field of study and what are you working on? Or How is shit going(e.g. Career wise, family, social life)
Homework could be permissible but needs to be up to an intellectual standard.
>>7778631
Anyone /Optics/ here?
>tfw applied to uni for physics
>tfw having last minute doubt over whether I actually like physics or if I just like the maths parts
>>7778723
Why not just also apply for maths.
Or take Analysis 1 and Linear Algebra 1 and Experimental Physics 1. Ana 1 and Lina 1 wont be wasted and if you like the physics part more you only continue taking Analysis the next semesters and continue the physics stuff, or you drop the physics stuff and continue math.
So what is consciousness made of exactly?
Is it anything tangible? For example, "race" is a collection of many genes expressed physiologically that are shared between a large enough population to be classified as a "race". Intelligence, inherent one that is, is a collection of many different genes that allow the capacity to function in different spheres of life. Could consciousness have something like that ascribed to it? Or is there a certain core to it all? Or am I off here on all accounts?
Consciousness is technically your senses giving constant feedback to your brain through your memory. It's a mix of your entire history and your genes.
It's not made of anything physical
>>7778543
consciousness is not made of anything "exactly", fgt pls
Where did this common misconception come from?
probably because high school nerds always show that distinct trait
Why does STEM often receive so much hatred? Has it always been like this? Or it is only a recent trend?
>>7778382
No its not that. Every comment I see around in forums online depicts some idealized scientist who "works hard" doing "real science" (as opposed to media endorsed pop sci).
Anyone bere knows sites to leaen biology-chemistry math-calculus end exercise?
This is my last year of school, and i am having lots of troubles because i found some gaps in my instruction, due to the fact that i didn't get anything to study from.I've always been very good in scientific subjects but this year i'm shitting bricks, sorry for any grammar mistakes, but i'm terrified(and foreign).
Please, i need help.
Guys those grammar mistakes are phone mistakes, sorry again.
It's not help with homeworks, i need a solid reference to improve my math skills
>>7778295
wut?
https://www.khanacademy.org/
has a bunch of intro level material
if you are looking specifically for problems to work on, just go to bookzz.org and download textbooks for free
ANY GENIUS HERE?
we have n x m grid and a x b rectangles
how to determine if we're able to cover whole grid with these rectangles, and if not what is the biggest ammount of rectangles which would fit?
algorithm/code would be very helpful?
thanks
halp me pls
all rectangles are the same size
I believe that this is the criteria for tiling the whole grid, but correct me if I'm wrong.
Each of a and b must divide either n or m (they may divide the same number or different numbers). If they divide the same number, say a | n and b | n, then you must have m = ax + by for some non negative integers x,y.
Engineer here (sorry).
Does this help?http://www.rmig.com/en/technical+info/formulae/calculation+open+area
I've decided to teach myself calculus, I have a fairly solid knowledge of basic maths (did my A level last year) but I'm not sure if the book I'm using is particularly well written. I'm struggling to get my head around the example in pic related, any help would be appreciated
He's just giving you an example of how the limit can be visualized and rationalized. If you were to have a function y = x/sin(x), at x=0 the function is not defined (because we cannot divide by zero). Knowing this we have to use something called a limit. It just shows as a value approaches a point, the function in question converges to another point.
If you draw the graph you can see that it looks normal (it will even look like it passes through (0,1) ), but we still cannot define it for x=0. Graph the function and it might make more sense.
tl;dr - The picture...
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>>7778063
Google squeeze theorem.
>>7778063
ocw.mit.edu / stewart if you're a baby / apostol or spivak if you're badass
