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/sci/ - Science & Math

 Name Options Subject Comment Verification 4chan Pass users can bypass this verification. [Learn More] [Login] File Please read the Rules and FAQ before posting.Use TeX with tags for inline and [eqn] tags for block equations.Right-click equations to view the source.  05/04/17 New trial board added: /bant/ - International/Random 10/04/16 New board for 4chan Pass users: /vip/ - Very Important Posts 06/20/16 New 4chan Banner Contest with a chance to win a 4chan Pass! See the contest page for details. [Hide] [Show All] [Catalog] [Archive] File: sciguide.jpg (9 KB, 200x140) 9 KB JPG https://sites.google.com/site/scienceandmathguide/ >> Reminder: /sci/ is for discussing topics pertaining to science and mathematics, not for helping you with your homework or helping you figure out your career path. If you want advice regarding college/university or your career path, go to /adv/ - Advice. If you want help with your homework, go to /wsr/ - Worksafe Requests. File: 1554117530759.jpg (24 KB, 399x503) 24 KB JPG if the sun is hot why is space cold 15 replies and 1 image omitted. Click here to view. >> >>11166356 Because you touch yourself at night. >> >>11166356 What are you doing here? >> >>11166862 "Over" being the operative word. That is not even that hot. Are you an Alaskan or something? >> >>11167095 No? I live in the south, but nevertheless I hate cold and hot weather. If it’s colder than 60’ and hotter than 85, I want to stay inside. >> File: 1563305845197.jpg (80 KB, 750x669) 80 KB JPG >>11166376 It actually isn't that cold because you are comparing two different things. The thermal conductivity of a vacuum is extremely limited if not totally absent compared to matter conductivity (itself contingent on medium, state of matter, pressure, etc). If you were ejected into space around earth without anything on, it would not be immediately cold, even in the absence of sun at minus 250. If you were surrounded by pressurized air at that temperature, you would nearly immediately freeze to death. You will die of hypoxia before "the cold" will kill you in space. File: meta thread.jpg (11 KB, 250x250) 11 KB JPG I tried speaking about the recent situation of /sci/ before, but was sadly censored. Before resuming to my previous points, I would like to get tangential for a bit. Due to the recent SW/SH debacle I've found myself on the /vp/ community. There was and is great turmoil in the community, shit being flung from side to side alongside the common threads and generals. Despite having its population split apart, all discussion was still focused on a single subject, pokemon. The atmosphere was friendly and open, you could still find your bits of bait, racism, degeneracy and shit posting. This however, didn't steal focus from it being a pokemon board first and foremost, for nerds deeply invested in the franchise and no actual political points were taken. The mix of freedom of speech and genuine interest from every anon are what make /vp/ an suitable home for fans to be. I truly believe /sci/ has the potential of becoming one of the best places for discussion of science on the internet. Unfortunately, this is being taken from us by foreigners who come to shit on our place to try and use science to voice their skewed opinions and biases with little to no regard to the native population. For how long are we going to allow disingenuous people with no true scientific interest to make our place theirs? A thing that I want you all to keep in mind is that I don't care or think we should care about random racism, critics or disagreement as long as it stem from the thought of the individual rather than organized movements and mob mentality. OP's text and thumbnail define what the thread will devolve into and at least that should be aligned with /sci/'s interests. I'm NOT pleading for censorship, I'm pleading for focus. 1 reply omitted. Click here to view. >> >>11167102 >>>/qa/ is for meta threads >> >>11167102 wrong science is still science, unfortunately we had to be wrong 100 times before we could be right about anything yes, its redundant having the same threads with the same rebuttals over and over again proving some idiot wrong but thats the scientific way of doing things, op >> >>11167113 You don't need to be a genius to see that they don't seek and are not open actual discussion. Only confirmation biases from other people with same opinions who also happen to be here. /sci/ should be open for the ignorant on the subject that has actual interest in learning. Like the guy who asked if someone would did if you sunk him on oil and lit fire on it or what if simulation is real. >> Maybe if mods and jannies would DO THEIR JOB AND REMOVE THREADS THAT ARE REPORTED FOR BEING LOW QUALITY this wouldn't be that big of a problem >> >>11167105 >Baity thread about evil whaman and global warming should not be here. Agree with trepidation. My degree is in Earth science and I'm pursuing a planetary science degree. While I will admit 'baity' climate threads should not be allowed I worry that people will claim 'every' climate thread is not allowed. Usually I come here and end up using my education to correct people's misunderstandings about how the climate works and it can be enjoyable because while people do post lots of garbage in such threads enough science is being discussed that someone who's goal is to pursue knowledge will gather some pretty good information. Perhaps I should make more science based climate threads. Perhaps I should make more science based climate threads. File: LecturerGroup1_web.jpg (346 KB, 962x425) 346 KB JPG everyone says Polchinski is the best, and that's the only one I've tried to read. what about the others? >Superstring Theory -- Green, Schwarz and Witten (1987) >Introduction to Superstrings and M-Theory -- Kaku (1998) >A First Course in String Theory -- Zwiebach (2004) >String Theory and M-Theory: A Modern Introduction -- Becker, Becker, Schwarz (2006) anybody have any feelings on whether any of these are better or worse than Polchinski? i've gone through polchinski a little and found certain things lacking and the pedagogical style a bit just "here do this" without enough motivation, as well as certain chapters where he goes "i don't explain anything here just state it as fact" which is annoying 20 replies and 1 image omitted. Click here to view. >> File: img0014.jpg (51 KB, 640x480) 51 KB JPG >>11165886 kek >> >>11166709 thanks anon >> File: img0036.jpg (82 KB, 640x480) 82 KB JPG just gonna post a rare witten bonus: vafa >> >>11164595 nima the only non-autist nigga here >> File: img0062.jpg (110 KB, 640x480) 110 KB JPG >>11166941 you think juan is an autist? juan has a wife and kids and stuff. and i understand from what i have seen that he still goes to catholic mass on a weekly basis bonus: another rare witten File: soya.png (15 KB, 412x434) 15 KB PNG >ARTIFICIAL INTELLIGENCE IS GOING TO TAKE OVER THE WORLD >ELON MUSK IS AN AI EXPERT HE KNOWS HOW ITS GONNA WORK >WE NEED TO MAKE SURE AI DOESN'T BECOME TOO POWERFUL KEEP IT IN A CAGE >THE SINGULARITY IS COMING AND WE'RE GOING TO BECOME ANTS >AI IS GOING TO TAKE OVER THE PLANET USING HUMANS AS ENERGY No end to these idiots huh? We're probably not going to get AGI for at least another 40-50 years. The AI google has built to answer phone calls can't even pass of as human and is nowhere near being capable of "thinking". 67 replies and 8 images omitted. Click here to view. >> >>11167146 I think the important point is human intelligence compared to animal intelligence. Human beings are not literally "mentally better" at everything compared to animals. Yet we in a sense do in fact seem to possess some kind of generic "mental betterness" that makes us effectively just that. It would be an odd coincidence if we were just lucky to be superior in so many unrelated mental abilities, and that there wasn't something that's almost like plain "mental betterness" - that is general intelligence. >> >>11167158 Your definition of intelligence is retarded and you don't even understand basic neurology bro. >> >>11167153 I don't think so. All of your tests are still about intelligence. My point is that the fear of AI is not that it's "intelligent" or that it's incorrectly intelligent, but that it's simply a supercharging of technology, and in particular technology that can be used to do bad things. The intelligence is *just a tool*. >> >>11167159 Dude are you like literally retarded. Take a basic course on anatomy, you can clearly see what makes humans """intelligent""" by comparing a chimp brain to a human brain. >> >>11167163 Uh what? What exactly are we disagreeing about here? File: 1561985999183.png (635 KB, 868x654) 635 KB PNG finite edition 35 replies and 11 images omitted. Click here to view. >> >>11167061 https://en.wikipedia.org/wiki/Homology_(mathematics) A sequence of groups associated to some other object we want to study. Comes traditionally from topological spaces but can arise in other contexts. The definition is not intuitive so you're not really going to understand it without having actually gotten your hands dirty. Homology/Cohomology are pretty powerful tools and relatively modern. >> >>11167082 "sequence of groups associated", so isnt that kind of everything? wahts a topological space? >> >>11167061 Singular homology: Let [math]X be a topological space.
For each natural number $n$ consider the collection of all maps from the n-simplex to $X$ (we call these maps n-simplices in $X$ or simply n-simplices).
Let $C_n(X)$ be the free abelian group generated by these maps (n-simplices), so an element of $C_n(X)$ is a finite formal sum $\sum_i a_i \sigma_i$, for $a_i \in \Z$ and [math \sigma_i [/math] an n-simplex.
Define a map $d_n : C_n(X) \to C_{n-1}(X)$ by sending an n-simplex $\sigma$ to the alternating sum of its faces, $\sum_{i=0}^n \sigma|_[\hat{v}_i]$, where $\sigma|_[\hat{v}_i]$ denotes the face of $\sigma$ spanned by the vertices other than $v_i$.
Extend this map linearly so it's actually a group homomorphism.
Then a simple computation shows that $d_{n-1} \circ d_n = 0$, so the image of $d_n$ is in the kernel of $d_{n-1}$.
Thus (since $C_n(X)$ is abelian), the quotient of the kernel by the image is a well defined group.
We call this group $H_n(X)$, the nth homology group of $X$.

>>11167091
>wahts a topological space?
https://en.wikipedia.org/wiki/Topological_space
It's like a really abstract generalisation of the notion of space. It's weak enough so that you have no notion of angle, distance, or lines, but you can still talk about things like continuity.
If you don't know what a topological space is then you've got a while to go before reaching homology anon.
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>>11167150
>consider the collection of all maps
Here map is understood to mean "continuous function"
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>>11167150
I really fucked this
>alternating sum of its faces
Should be [math] \sum_{i=0}^n (-1)^i \sigma|_{[\hat{v}_i]} [math]

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>>11163777
Guyton and Hall covers most things you'd need to understand every organ system to a moderate level
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>>11163777
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>>11164617
>The Bible by Jesus
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>>11163777
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>>11164617
Would add something from Kirkegaard. +1 on the bible (because it was influental, half of our sayings are from there, there is eroticism and logical paradoxa inside and the christian faith is an actually interesting construct once you are out of the "hurr some people need a magic skydaddy" phase"). Would also add Gödel Escher, Bach because it is really entertaining. The concept of self-reference is fun.

I'm of the understanding that quality is of objectivity. "Of", because it's plausible having Pavlovian responses to garbage media, based on subpar environments. .. "It's not even really debatable." Responses are usually simply "but subjectivity", which is arguing a negative – while scholarly media is already qualifying and quantifying specifics. It's something that effects products, critiques, and other media.

Janny spoiler: https://pastebin.com/Ndc8F1qR
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Are you ESL? Your sentence structure is shit and you don't seem to understand what words mean.

Just because you can find a bunch of people who have the same qualia experience does not make it quanta. The data sheet that you have about their preferences is quanta, but their opinions themselves will always just be qualia.
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>>11166999
Absolutely massive waste of an incredible get.
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>>11167048
>Are you ESL?
No.

>Your sentence structure is shit and you don't seem to understand what words mean.
>[Not a specific criticism or argument].

>Just because you can find a bunch of people who have the same qualia experience does not make it quanta.
"Specifically .."

>The data sheet that you have about their preferences is quanta, but their opinions themselves will always just be qualia.

>>11167059
>[Not an argument].

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What is the scientific reason for why men tend to dominate STEM if women are just as smart (if not smarter!!) than men?
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>>11166785
>lol, so women are superior because they act emotionally rather than rationally.
You didn't even understand his post anon

>>11166777
>he likes PNAS
Me too.
https://www.pnas.org/content/116/31/15435

Based on PISA scores of 300,000 15-year old students (but it wouldn't be surprising to see subject GPA studies bear the same result), we get this evidence (pic related):
In both boys and girls, it's not math skill or reading skill, but _the difference between them_, that predicts intention to study math.

Among top scorers, the reading gap gets even larger, i.e. the better the boy is at math, the shittier he is at reading when compared to girls of the same math tier. Not going to call it autism but just as a side note g is far more strongly correlated with verbal skill than with quantitative reasoning.

Interpretation: People prefer to do what they're good at, and avoid what they suck at. Thus, boys overwhelmingly select the sciences. Even without the negative societal pressure, less women would select STEM, proportionally, because within any given tier of math skill, the girls outperform the boys at reading, leading them to feel comfortable pursuing a wider range of disciplines on average.

Conclusion: the STEM gender gap is more about the boys than the girls. Improved reading / verbal skills training for boys at a young age could change their propensity to hard funnel themselves into the sciences.
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>>11166850
>You didn't even understand his post anon
i did, fren. the point i as making was mocking how ridiculous it is to pick your study based on whether or not you're "repulsed" by your peers instead of what interests you, you're good at (related as you pointed out) and gives you the best job prospects.
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>>11166390
Source?
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>>11166963
http://archive.boston.com/news/education/higher/articles/2006/02/22/summers_to_step_down_ending_tumult_at_harvard/
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>>11147920

K-12 Science and Math
>Follow directions and perform basic critical thinking
Professional STEM
>spend 95% of your entire life trying to turn lead into gold so you can become the next Einstein or Von Neumann which only several hundred or so humans have achieved since the birth of civilization.

The last one is the hardest sell to a woman and it shows. All the other shit is simply a matter of time.

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The front fell off edition

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>>11167000
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>>11166987
>I have some doubts it will be that good on Mars because of the size of xEMU suits that basically turn everyone into a 500 pound obese person
on the plus side, going to mars has been proven to be one of the most effective weight-loss programs mankind's ever devised
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>>11167000
>>11167008
>>11167013
>99x99
Kys phonefags
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>>11167065
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>>11166987
Elon has said the driver seat would fit somebody like Andre the giant (7ft 4, 500++ pounds). Will know if this is true in a couple of hours.

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Going on a date with some chick who's studying math. Can i get some math related meme?
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Are stem chicks into black guys? I'm a black nuclear physicsists and still a virgin but would love to pipe a white girl
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>>11163841
Yeah wow this fake airbrushed bitch is sure hot oh my god. You're retarded if you think she is actually attractive when she wakes up in the morning.
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>>11166561
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>>11164448
Don't worry, this generation is lost, but the one after it will maybe get it. I mean I think there a differences also intellectually and personality trait waise...but they are only statistical trends and say nothing about an individiual. There is nothing wrong or impossible about a l33t woman that also has a good looking body. Not that it mattered, but those exist and why not?
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>>11166699
I really hope this is not your pic tho that kind of stuff rarely ends well on 4chan. Pretty tho. Now I need to see code

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>>11166946
because whenever an 11 year old looks smarter than grad students, all the grad students here get all insecure about how some kid will BTFO them.

thankfully in 2019 we see that Barnett turned out to be a meme who latched onto Lee Smolin which implies he will forever be a meme, so now we can feel OK about him. look, Sabrina P. was a big meme here but now in her postdoc she isn't revolutionizing physics so now the other postdocs here aren't worried about how she's level 4000 above us.

science people are super insecure. and if some little girl gets cited by Hawking or if some middle school boy gets accepted to grad school, it makes us look like we're trivial. but after time passes, those memes dissolve and normal career scientists stop worrying that they've been bested by child prodigies

look, Stephen Wolfram was a child prodigy and published his crap book in the 80s. where did that go? nowhere. he sold out and became a software guy. maybe he is rich because we use his software but he never ended up doing anything good in the field he got his degrees in. he was never nothing to worry about
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>>11165825
Favorite class is Greek language.
Wants to study the bible.

WTF?
What happened to his multi dimension ring theory stuff where you drop a hand full of coins and shit?
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>>11166993
anon, that's a different guy. obviously. if you don't have face blindness. or "voice blindness" (which i just made up).

remember that jacob barnett is an autist. does that guy seem like an autist? no, he's a chadlet. barnett is a permavirgin. keep these things in mind.
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This type of thing would make sense if we still used words like "savant" instead of genius lol,
"I can't speak properly or dress myself, why didn't I ever write a new theory of relativity....."
He had a photographic memory and was prompted to make his claims,
This is child abuse if anything, photographic memory means he can just reference other people work or fill up a blackboard with maths.
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>>11167089
should have just become a chess pro

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I am conducting a research experiment to analyze how e-cigarette (specifically JUUL) vapor affects the bacterial growth of a certain probiotic that is known to have benefits on oral health (a strain of Streptococcus salivarius). Essentially my plan after culturing the bacteria was to expose the bacteria to various e-cigarette vapor (of different flavors) to see how bacterial growth would be impacted, among other things. My question is, what could be an efficient and safe way to do this assuming that I have a somewhat small budget. I looked into vacuum chambers and bell jars but I might be putting too much effort into "extracting" JUUL vapor in a chamber or something just to expose the bacteria for just a short while.

If I wanted access to an article or book to reference in a university essay, would I face disciplinary action if i used these two websites to access the material

sci-hub.se

http://gen.lib.rus.ec/

Suppose all i did was just cite the article and gave no indication where i accessed it. Would they know I used scihub/libgen and invalidate my work?
No i won't use university wi-fi to access the pages and if i did I'd use a proxy.
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>>11165812
"I do not remember how, there are many references in my work. I cannot remember how I found each of them"
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>>11164156
This. If you email a professor about a paper they wrote they're liable to email it to you if you're a good sort.
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>>11164156
>tfw your linalg professor shows the class how to google for the pdf of the textbook on the first day
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>>11165812
They wont though. No one gives a fuck. Just don’t distribute it or print out copies and sell it.
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>>11165566
In my opinion, the corporations and their legislative puppets have collectively subverted copyright law
into a perpetual money machine, benefitting nobody but the executive class and their fellow parasites.

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Where are memory stored in brain? Is it a molecule? Can I see them with microscope?
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>>11167107
We know it does. As to how it does it we haven't a clue. Go into neuroscience and figure it out for the rest of us.
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>>11167097

Basically my post was that there are obviously people who know more than the public about memories but they keep it to themselves thinking they are steps ahead of everybody else, when they don't consider enough about whether or not they understand any thing...

and that includes random argumentation against me.
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>>11167062
His brain doesn't.
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>>11167115

It's pretty interesting to assume that the brain was created on its own by natural forces on life causing evolution...

weird...
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>>11167097

Basically what I'm saying is that surely there are people who are making sure that they are the first to find out if anybody is to find out eventually about new information about brain things but in the quest to control what is known, they may not realize that anything could be wrong.

Nothing is guarenteed except taxes and God, and we might do something about taxes one day

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