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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.
Message too long. Click here to view the full text.

7 posts and 2 images omitted. Click Reply to view.
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 14/04/18(Fri)01:45 No. 15631 ID: 0f9d09 [Reply]

File 139777830659.jpg - (617.08KB , 575x1673 , exoearth-habitable-rocky-earth-kepler-186f-140416a.jpg )

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.

Anonymous 14/02/23(Sun)14:05 No. 15550 ID: c4b814 [Reply]

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is .999...=1?

17 posts and 2 images omitted. Click Reply to view.
Anonymous 14/04/10(Thu)08:48 No. 15622 ID: 7038af

I guess I'll weigh in

This is actually one proof...
(1/3) = 0.333...
3*(1/3) = 3 * 0.333...
then through elimination, the 3's on the right drop
1 = 0.999...

The one that first made sense to me was posted before
Say 0.999... does not equal 1.
x = 0.999...
10x = 9.999...
10x - x = 9 (Removes the infinite 9s)
through simplification
Message too long. Click here to view the full text.

Anonymous 14/04/16(Wed)22:58 No. 15627 ID: e65a14

>it could be described as infinitely close to 1, though
does not compute. it's simply a proven fact that it is 1, full stop. any ideas that consider it to not be 1 are just wrong. it's not "so very close to one that our imprecise maths consider it to be one". it is precisely 1, absolutely no difference.
>You weren't removing 1 from 10x, you were removing 0.(9)
They're the same thing.
>I don't see the logical connection where it was determined that by removing x from 10x, x suddenly becomes 1 instead of 0.(9)
It didn't become that, it always was that. But in any case: 10x-1x=9x. That's true no matter what x is, okay? It's basic algebra. 9.9...-0.9...=9. It's simple subtraction. Again, this is indisputable. Now, you have to understand that 9.9...-0.9...=10x-1x. We define x as 0.9.... Multiplying that by ten, we get 9.9.... So it is necessarily true that 9.9...-0.9...=10x-1x. Now we can substitute 9x in for 10x-1x and substitute 9 in for 9.9...-0.9... because of the equality we established earlier, meaning we get the new equation 9x=9. Simplify, and we are left with x=1. This is all basic algebra that's easy and you can't not accept the conclusions. If you don't want to accept the conclusions, then you just wanna reject proper maths.

Anonymous 14/04/17(Thu)06:33 No. 15630 ID: 789203

All you're saying is correct, but the way >>15560 presented it was not. In particular, this:
>10x - x = 9x
>9.99... - 0.999... = 9
Writing two equalities one on top of the other is conventionally understood to mean a double implication between the two. While 10x - x = 9.999... - 0.999... by definition of x, it does not follow that 9x = 9 (although it follow from the previous equality). Basically, the problem is that two steps in the reasoning got merged into one.

A preferable way to make the statement would have been
9x = 10x - x = 9.999... - 0.999... = 9
9x = 9

Anonymous 14/03/29(Sat)07:53 No. 15610 ID: b6dcec [Reply]

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This guy makes a big claim:

Ignore the fact that it's on /phi, a veritable desert of scientific literacy. I am curious about this claim. I've worked with some nuclear physicists and engineers from my time in the military, and have had many conversations with them about the test era, cold war, fallout, nuc winter and whanot. I've never heard anyone ever make the case this fellow is making. Anyone care to put some numbers to calcs and illustrate one way or the other? What a curious idea.

2 posts omitted. Click Reply to view.
Anonymous 14/04/13(Sun)01:41 No. 15624 ID: ab6a9a

This dipshit doesn't understand that the human race has almost reached critical mass where we are impossible to wipe out. Nothing short of the entire planet being destroyed would kill us off.

Anonymous 14/04/17(Thu)03:52 No. 15628 ID: de1e75

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a lot of it would depend on those nuclear weapons still being operational. they have a shelf life... assuming that a good proportion of them worked in the first place.

the idea being that if there was a nuclear war, there wouldn't be anyone around afterwards to prosecute manufacturers for providing nukes that didn't work.

they can't test them all.

Anonymous 14/04/17(Thu)04:32 No. 15629 ID: 15121f

Youtube - Toggle Video
Don't feel so comfortable. A nuclear winter lowers global temperatures by throwing up ash into the atmosphere that takes years to settle. A smaller and similar even occurred with a volcanic eruption I believe during the turn of the 19th century. Temperatures only fell in Europe by a few degrees (Celsius) and it still provoked a food shortage.

Nuclear winter = worldwide famine. Closer to the equator people have the best chance of survival, but that's assuming they haven't succumbed to radiation sickness or other problems associated with the rest of the world going kablooie.

Basically don't shrug off the near-extinction of a great proportion of the planet's life; think what it would do to our society, and how difficult rebuilding would be amidst further wars securing the last habitable land.

Anonymous 14/02/27(Thu)08:32 No. 15564 ID: 43639f [Reply]

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I found a 3TB 1.8" hard drive. Will it function with a iPod video.

Anonymous 14/03/14(Fri)01:37 No. 15591 ID: f6de22

What is the original drive size of the iPod Video in question?

Anonymous 14/04/13(Sun)01:20 No. 15623 ID: 32e7bd

Probably not, iPod Videos don't use SATA and I'm almost positive that you've found a SATA drive.

Anonymous 14/04/16(Wed)22:38 No. 15626 ID: 3c414f

File 139768069373.jpg - (2.12MB , 3395x4680 , 1341060488062.jpg )

Before you do anything, on a working windows machine, mount the found drive and run "Recover My Files" and "Recuva", get this from any torrent host.

See what you find and share it here.

um Anonymous 14/04/05(Sat)08:57 No. 15616 ID: 621fec [Reply]

File 139668102699.jpg - (64.71KB , 720x720 , HELP.jpg )

answer in the book is:

14 - sqrt7/9

Anonymous 14/04/08(Tue)02:49 No. 15618 ID: 6fd539


Anonymous 14/04/10(Thu)08:28 No. 15621 ID: 7d617a

2nd to last step: you have to divide the 2 in front of the sqrt7.

1/2 * (28 - (2sqrt7)) = (1/2 * 28) - (1/2 * 2sqrt7)

Anonymous 14/01/02(Thu)13:09 No. 15498 ID: d96d83 [Reply]

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Should a loli be the mascot of GNU/Linux instead of Tux, /sci/? Lolis are a symbol of peace and freedom, after all.

11 posts and 1 image omitted. Click Reply to view.
Anonymous 14/03/12(Wed)22:11 No. 15590 ID: b269d3

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MacOS X does have a mascot.

Anonymous 14/03/21(Fri)11:19 No. 15599 ID: 4a88ee

Source on that?

Anonymous 14/04/06(Sun)11:11 No. 15617 ID: 2d9ae3

Actually windowns luser are disgusting perverts.

America VS the metric system Anonymous 11/11/28(Mon)22:57 No. 12847 ID: 2dcfee [Reply] [First 100 posts] [Last 50 posts]

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It’s hard to find comedy gold like this, however this is priceless


Apparently a true American tries to show the failures of this evil satanic scientific metric system and fails horribly.

Best parts:

1) Arguing that centimeters are not part of the metric system!
>"Centimeters, while in common usage, are NOT officially recognized metric units"

2) Actually trying to measure something using 0.1 mm obviously not understanding that this precision is not actually possible with human hands.
>"In metric notation this would be 1219.2mm by 2438.4mm."

123 posts and 10 images omitted. Click Reply to view.
Anonymous 14/02/12(Wed)03:58 No. 15537 ID: 44326e

This attitude is why we're still stuck in the past.

Anonymous 14/03/14(Fri)04:09 No. 15592 ID: 1615b6

this attitude cost mankind one satellite. good job.

Anonymous 14/03/16(Sun)07:12 No. 15596 ID: b6dcec

And this attitude is why he won't be working with a great many people in his own country.

Enjoy your exciting job in retail, OP.

Anonymous 14/03/20(Thu)01:53 No. 15598 ID: 18d91e [Reply]

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Why did Dr. Carl June use a lentivirus like HIV? Why not just use a plain old engineered plasmid? Though I've cast doubts on the fact that it was actually potent (or even reengineered) HIV administered to the loli. why would he risk it? To sensationalize his discovery with that "fire with fire" prospect? I don't know much about immunotherapy research for cancer, but it seems strange. I doubt he used it without proper cause, obviously.

Anonymous 14/03/27(Thu)13:58 No. 15608 ID: c2fd35

1) Specificity: Viruses can be directed to attach to certain cells (expressing certain proteins on their surface) very easily. Low chance of accidentally targeting healthy cells.
2) Stability: a bare plasmid would quickly be broken down in the body (by white blood cells/lymphoctyes/whatever), if our body allowed any random bits of DNA floating around to survive we'd die out pretty quickly. A plasmid within a bacterium would also induce an immune response, as well as not being very good at getting to specific cells within a tumor.
3) Low/no need to repeat therapy: lentiviruses transcribe their genome into the cells they infect, so they effectively turn the cancerous cells into factories producing things to kill themselves with. A normal gene therapy would need multiple doses to ensure every malignant cell was hit, with a lentivirus a sufficiently high initial dose would ensure than even if not every malignant cell was killed initially they wouldn't be able to survive indefinitely, as eventually the "killing gene" introduced by the virus would be activated (having to throw grenades at someone until they die vs. magicking grenades into their pockets until they don't take one out in time and die. It's easier, less dangerous for people nearby and cheaper.)

There's probably more stuff that I've left out but I have to get to class...

Amazing Way to Test Batteries! Kliker 14/03/21(Fri)18:02 No. 15600 ID: 98dc66 [Reply]

File 139542132538.gif - (2.66MB , 711x400 , z.gif )

A simple method to test any alkaline battery in seconds! Works on AA, AAA, C, D batteries.
You can separate good from bad.

Kliker 14/03/21(Fri)18:05 No. 15601 ID: 98dc66

Youtube - Toggle Video

video john 14/03/21(Fri)18:11 No. 15602 ID: 98dc66


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