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/sci/ - Science, Technology, Engineering, and Mathematics

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New Textbook/Book Request Thread deadbabies ## Mod ## 13/08/25(Sun)06:03 No. 15270 ID: f34135 [Reply] Stickied

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First off, hello there, I'm deadbabies, and I will be taking over as /sci/ moderator. Rules will remain the same. Please use the report function if you see posts that violate the rules, but also do not abuse it.

I have officially expanded the scope of /sci/ a bit. You may discuss Science, Technology, Engineering, and Mathematics here now. No science is discriminated against as long as it's of the peer-reviewed variety. If someone wants to discuss Anthropology or Social Science, by all means, let them. If you do not like it, just don't post in the thread.

The IRC channel #/sci/ is now (finally) re-registered and I am running as operator on here. Feel free to stop by and say hi. I do leave my computer idling on IRC, so check back or leave me a message if you have any ideas, suggestions, or just want to tell me off. You can get onto #/sci/ by joining the server irc.7chan.org at port 6667. You can also use SSL at port 6697 but you will have to set your client to accept invalid certificates.

ADDITIONALLY and IMPORTANTLY I have had several requests on IRC regarding the old Ebook FTP that we used to have. Unfortunately, the mod who ran it entered the military and no longer runs or maintains it. I have no plans to make another one, but if one of you guys would like to, by all means advertise here.

That being said, I'm just going to leave this link here:


You may find what you seek here.

I will be unstickying the old ebook/source articles thread. Please post any new ebooks/source articles here, and feel free to post any working links from the old thread there; I will eventually be deleting it.
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Anonymous 13/09/17(Tue)06:00 No. 15308 ID: ba9e6c

bib.tiera.ru is back up - lots of math and physics texts are available there

Anonymous 14/10/19(Sun)11:15 No. 15940 ID: e9758b [Reply]

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How much money you reckon ebola raised for in the name of science? thanks little fella!

Anonymous 14/10/19(Sun)11:33 No. 15941 ID: be3d41

Thank the dead.

Anonymous 14/10/20(Mon)23:08 No. 15944 ID: bac648

hey, it's not like we thank the dead sand people we kill for oil... credit where credit is due

Anonymous 14/09/20(Sat)07:30 No. 15881 ID: ea642d [Reply]

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should i get a mac book pro or a window for computer science?

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Anonymous 14/10/18(Sat)10:30 No. 15938 ID: a417b7


either dual boot it or linux on a virtual machine

Nattajerk 14/10/20(Mon)22:34 No. 15942 ID: e55706

I wish I had prestanda.

so anyways, I went and bought a macbook air - putting my money where my mouth is.

I am enjoying it. It runs cool, it feels cool. It's like a menthol cigarette. After having installed macports on it everything feels comfortable - like back when I was using debian on my old nuclear reactor that is the HP laptop. though with less outdated packages.

the meta/alt/control keys (clover key? i dont know, it's silly) are interesting, it definitely has a bit of learning hotkeys and mouse gestures to it, but once you get the hang of them it all moves very fast. I like the notification bar, simulated control click, etc.

they keyboard is nice to the touch and clicks and clacks like you're making love to it.

and I have.

anyways, I wouldn't suggest buying it unless you got cash to burn, as its going to be a quarter to twice as expensive as a laptop of the same specs.
but damn, the weight of the machine is almost nothing, 2.8 pounds. i can lift that with 3 fingers comfortably.

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Nattajerk 14/10/20(Mon)22:39 No. 15943 ID: e55706

also apparently prestanda is a swedish word for the amount of useful work accomplished by a system.

det är underbart

Anonymous 14/07/25(Fri)22:51 No. 15766 ID: 86e709 [Reply]

Youtube - Toggle Video
  Everything I've read about Eugenics has been about how it's pseudoscience. Ok. but, by the sound of it, it was just a selective breeding program. If artificial selection works in every other species, and natural/artificial selection has produced us, ...where's the problem exactly? I have yet to see how a sophisticated selective breeding program couldn't produce a better human body or brain or both. It's what we do every time we pick a mate who we think will make us some primo offspring.

pic semi-related: Just try listening to this without clawing your eyeballs out (why are so many people so fucking retarded and how can we replace them with upgraded models?)

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Matchbox Prince 14/10/10(Fri)11:24 No. 15927 ID: 2f260d

It primarily doesn't work because humans are bastards with ulterior motives. All that happens with eugenics is a bunch of rich/powerful people genociding everyone who isn't rich/powerful and making inbred retard babies with each other.

(Also, I have determined that your holding a subjective opinion [techno music is bad and people who listen to it are "retards"] as an objective reality means you are non-qualified to be one of these "advanced humans". Prepare to be eliminated.)

Anonymous 14/10/15(Wed)04:41 No. 15935 ID: 8d2cfb

Cuz, it's too far down the rabbit hole just like gmo's

it scares the average person I guess, otherwise there'd be more suport

The scientific reason against eugenics is this... we are ignorant! Jesus Christ! If any person actually thinks the positives outweigh the negatives of a selective breeding program in humans, they are naive! Humans are peculiar in their genomes, there are so many factors we are only beginning to understand. The combinations are far more endless than the average person currently fathoms. Our only issue as a species should be this, preserve diversity. Granted, this should concern our natural, fleeting environment than our horrendously artificial population.

PlutoniumBoss!Y1SVQJ54eA 14/10/19(Sun)09:43 No. 15939 ID: 465a65


There's also the point that artificial selection can produce all sorts of fucked up results. Just look at what we've done to the various breeds of canine. Larger breeds tend to develop hip and joint problems because we've made them bigger than their bodies can handle. Systematic cosmetic inbreeding of the decorative species has led to increased genetic defects and health problems.

Anonymous 14/10/12(Sun)19:00 No. 15929 ID: b20a90 [Reply]

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Hello /sci/!

Does anyone please know of a program that can analyze torrents? What I want it to do is to create a printout of all the files in the torrent. I also want to make comparisions of torrents; to see if two torrents have files with the same name and/or the same hash value.

Anonymous 14/10/16(Thu)11:00 No. 15936 ID: 789203

Yes, dumptorrent.

Hashes are computed per-block, not per-file. Meaning, the hashes a torrent contains will depend not just on its particular contents, but also the particular order in which they appear, and the block size that was used. It's very unlikely that two distinct torrents containing the same file will also share any hashes, even if the block sizes are the same. It's even less likely if the file in question is smaller than twice the block size.

Let n be the absolute offset of the file on the torrent A (given by the sum of all the file sizes that came before), and let m be the same on B, if file_size >= block_size * 2 and n is congruent to m modulo block_size, then there will be at least one duplicate hash between the two torrents. For randomly constructed torrents (a reasonable situation) with a random file_size the probability of the congruency condition being met is of 1/block_size. So for block_size = 4 MiB (a common block size), the probability is lower than four million to 1.

Anonymous 14/10/07(Tue)08:26 No. 15918 ID: 1b02b6 [Reply]

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2 questions. In photo,

Exhibit 1: A point charge q exerts its electric field over a spherical body. Along the flux lines diverging "radially" away from point charge, there exists 2 points at opposite ends of sphere's surface area (along diameter). The electric field, E, in accordance with Coulomb's law, is stronger towards the charge than away from it, the vector lengths of E indicating this ever dying weakness, and vectors, dA, normal to the area.

Told: That the total electric field on the body is zero, because the cross product of the electric field on both points are "equal" but opposite, cancelling each other out. This applies to all points along surface area of the sphere.

Question: What is wrong in my photo? It seems that they have completely forgotten about Coulomb's law, in that the closer you are to a body, the stronger the electric field. If the point charge was negative, I imagine the electric field vectors to be a lot larger along the sphere's hemisphere closest to the point charge, and smaller on the other hemisphere. Wouldn't all but the tiny difference between the electric field strengths remain after cancellation? Shouldn't the total electric field be in slight favour of the negative charge's force?


Exhibit 2: a. A point, p, inside charged sphere has an electric field, E, of zero.
b. A point, p, exists in the sphere of a charged similar body comprising a sphere with an attached appendage that loops around half the sphere, with same electric field as E in exhibit 2a.

Told: That in all closed surfaces, the net electric field, E, at any point in the closed system is zero.

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Anonymous 14/10/07(Tue)09:10 No. 15921 ID: 1b02b6

Also, why are the charges along the surface? Is it just easier to think that way after summing all the negligible point charges together?

Anonymous 14/10/10(Fri)03:15 No. 15926 ID: 789203

1. I don't see how the field strengths on the surface could possibly have opposite directions unless the point charge is inside the sphere.

2. I agree with you, it seems counter-intuitive. I could easily construct a closed fractal shape that has infinite surface area on one side of the charge and is nearly spherical on the other. I'm not in physics, so I don't know what to tell you. See if this link helps:

Anonymous 14/10/10(Fri)19:00 No. 15928 ID: 1b02b6

I worded it poorly. E isn't opposite on both ends, dA is (normal to the surface on opposite ends). I was just trying to say that the field dies off the farther you are away from charge.

Nokia Cutter 14/09/30(Tue)10:08 No. 15900 ID: 91d0e5 [Reply]

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Is it even possible to get an old Nokia phone on a modern service provider ? I realized that I never use my iPhone for calling so it would just be better to get an iPod and a different phone. What do you guys think ?

Anonymous 14/10/07(Tue)03:51 No. 15916 ID: 1d75bc

If you mean using an old Nokia on a modern providers network?
Then YES. Plenty of networks still run 2G (GSM/GPRS/EDGE) channels for backwards compatibility and emergency dispatch services until 2016 (US) and 2017 (UK). Though reception can be patchy.

If you mean getting an old Nokia on a new service plan... oh wow.... seriously?

Realistically you're best off holding off a couple of months for the Nokia 3310 - Pureview as it hold to it's namesake for quality but with 3G which'll keep it going into 2030.

Anonymous 14/09/18(Thu)21:20 No. 15877 ID: 6cf8dc [Reply]

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I got drunk last night and got to thinking... what is stopping lightning from striking houses and tv antennas outside and shit when houses today aren't made with lightning rods?

Matchbox Prince 14/09/20(Sat)07:57 No. 15883 ID: 2f260d

1) Houses don't generally have large TV antennas anymore.

2) Houses are generally surrounded by taller structures like streetlights and trees.

Nattajerk 14/10/01(Wed)23:36 No. 15904 ID: ee6591

this ancient device you know as a tv antenna is connected to ground, and provides a clear path for electricity to follow. radio towers are frequently struck for example, the idea is not to avoid lightning but to divert it.

so, in essense, nothing is stopping lightning from striking your house. it is rare, of course. trees, taller buildings, etc will take the most risk of being struck, but having your property struck is certifiably rare by comparison.

Sifted 14/09/26(Fri)02:55 No. 15892 ID: 96405d [Reply]

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So for everyone out there I ask you what you think the universe would be like if attraction was different. If it was likes attract and opposites repulese, so two positive charges attract same with negative and then a positive and negative repulse. What do you all think?

Anonymous 14/09/26(Fri)03:51 No. 15893 ID: b3bbbb


Not much different. different flow for particles, different rates, different exchange, but not much else would be different.

Even on a large scale, it would pretty much be the same.

Sifted 14/09/26(Fri)06:02 No. 15896 ID: 96405d

I realized for the most part it would be the same but I meant like the stuff like black holes. Instead you would get a negatively charged or positevly charged one and instead of becoming a string you would lose all the electrons or protons in your body instantly. That would be insane if its the proton one you would just disappear the electron black hole would create a nova burst of energy. That would be insane.

Anonymous 14/09/26(Fri)19:30 No. 15899 ID: 801f00

Atoms wouldn't bind the same at all, compounds would be very different. Humans as we know them wouldn't exist. Chemistry as we know it wouldn't exist. Everything would be different

Anonymous 14/04/18(Fri)01:45 No. 15631 ID: 0f9d09 [Reply]

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So they found a new exoplanet that may be habitable, 490 light-years away. That is so great I guess Palestinians and Jews will stop killing each other now.

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Anonymous 14/09/18(Thu)21:22 No. 15878 ID: 6cf8dc

idk. just genociding kikes and sand niggers sounds easier and permanent

Anonymous 14/09/19(Fri)22:48 No. 15880 ID: 543811

where does one cast their vote for this?

Anonymous 14/09/26(Fri)07:22 No. 15898 ID: 2ea413

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There will be no devout mudslimes infesting our new worlds. Medieval thinking, medieval aspirations.
Lol hard, then take a breather, then lol some more :)
Nice pic btw.

Don't shill UN propaganda here, this is a place of science, not politics. The planet can comfortably sustain 20 billion people with our current tech level. Basically think how the USSR imploded and how this is the model the UN wants to impose to 'solve our problems'.

The future belongs to innovators and thinkers, people with the drive and spirit of freedom and inspiration, not pencil pushing mooks who absolved themselves of their humanity for a paycheck.

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