-  [WT]  [PS]  [Home] [Manage]

  1.   (new thread)
  2.   Help
  3. (for post and file deletion)
/sci/ - Science, Technology, Engineering, and Mathematics

Join us in IRC!

•This is not /b/ or /halp/. Tech support has its own board.
•If you are not contributing directly to a thread, sage your post.
•Keep the flaming at a minimum.
•Tripcodes⁄Namefags are not only tolerated here, they are encouraged.
•We are here to discuss sci-tech, not pseudoscience. Do not post off-topic.

•♥ Integris

  • Supported file types are: GIF, JPG, PNG
  • Maximum file size allowed is 5120 KB.
  • Images greater than 200x200 pixels will be thumbnailed.
  • Currently 476 unique user posts. View catalog

  • Blotter updated: 2011-01-12 Show/Hide Show All

Movies & TV 24/7 via Channel7: Web Player, .m3u file. Music via Radio7: Web Player, .m3u file.

WebM support has been added on a trial basis. Please check this thread for more info.

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

File 137740339172.jpg - (401.45KB , 1680x1050 , titanfalsecolor.jpg )

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

Why competition? Anonymous 14/08/22(Fri)10:34 No. 15829 ID: 080683 [Reply]

File 140869646585.jpg - (151.24KB , 600x781 , Discworld_Death_by_RobAnybodyFeegle.jpg )

This is most probably from complete lack of commonly accessible hard knowledge, but here's the question:
(1) If genes spanning individuals and species really do compete for survival as units of evolution,
(2) do the levels of competition seen in the natural world really benefit their survival?

They say, there's 1% genetic difference between humans and chimpansees, whatever that precisely means. Is intense competition between and within species not too counterproductive for genes' survival? May there be other, overriding controlling processes that steer genetic evolution from its optimal, maybe more cooperative behaviour?

Also, stupid philosophical crap for your amusement, because I have a psychological need to dump it somewhere: http://whitefielde.wordpress.com/

Anonymous 14/05/16(Fri)14:05 No. 15669 ID: 1ac70f [Reply]

File 140024190235.jpg - (10.83KB , 480x360 , hqdefault.jpg )

Any mathematical biologists here? I came across this post about mate choice and I'm not sure if it's a work of near-genius or complete stupidity. Are the arguments right?

The basic claim I'm making is that men have evolved to prefer young virgin girls because they have the greatest long term reproductive potential. You have argued that an adolescent girl would make a poor mate choice since she wouldn't be in her mating prime. I'm going to try to show to you that your position is wrong with a bit of mathematical reasoning.

The first thing I want to show you is that girls who started reproducing in their teens were reproductively more successful than those who started later in their 20s or 30s. It's going to take a bit of mathematical thought so get ready.

Let's imagine there was some ideal age, X, for the females in a species to start reproducing. Females who start reproducing at about this age leave behind the most surviving offspring. Females who start reproducing significantly later that age X leave behind fewer surviving offspring on account of having a shorter reproductive lifespan (since they started reproducing later) and those who start reproducing significantly earlier than age X also leave behind fewer surviving offspring due to them suffering more pregnancy complications and the like. The details don't actually matter that much. It's the principle that reproductive success is dependant on age of first reproduction and forms some kind of peaked distribution centred on the ideal age X that counts. Something like this:


So, what's going to happen under these conditions? If you think about it, it's really simple. Females who start reproducing later or earlier than age X will leave behind a suboptimal number of offspring and over time become a minority in the population. While females who start reproducing at about age X will leave behind the most surviving offspring and therefore come to dominate in the population. The typical age that the females start reproducing will automatically stabilise around age X, since, by definition, females who start reproducing at age X are the reproductively most successful! In a species that is adapted to its environment, the average age and the optimal age of first reproduction will be the same thing.


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

23 posts and 3 images omitted. Click Reply to view.
Anonymous 14/08/13(Wed)17:28 No. 15821 ID: 789203

>the optimal number of offspring at the correct rate
Which are what?

Anonymous 14/08/13(Wed)18:13 No. 15822 ID: 15a0df


It's mathematical necessity. Females that produce too many offspring so that too few survive and females that produce too few offspring to begin with will, over time, become minorities in the population. Females who produce the right amount to maximise the number of offspring that survive and reproduce will come to dominate in the population since, by definition, they are producing the most descendants.

Under natural conditions like foraging societies human females reproduce at a rate of about 1 per 3-4 years over about a 25 year period from the late teens to the early forties. This amounts to about 8 offspring, of which about 2-3 on average survive to reproductive age and reproduce themselves. This must be approximately the optimal rate for human females to reproduce under natural conditions.

Anonymous 14/08/21(Thu)13:04 No. 15828 ID: 597595

File 140861905068.jpg - (51.96KB , 983x549 , VR0pR.jpg )

Meteorite Anonymous 14/08/18(Mon)20:37 No. 15827 ID: 040c46 [Reply]

File 140838707141.jpg - (104.25KB , 960x741 , Lunar Meteorite.jpg )

Kickstarter campaign to purchase Lunar Meteorite


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

File 13931607112.jpg - (17.06KB , 500x390 , 10768_273185959499082_1150917839_n.jpg )

is .999...=1?

41 posts and 4 images omitted. Click Reply to view.
Anonymous 14/08/15(Fri)06:46 No. 15824 ID: c85029

File 140807800432.gif - (286.60KB , 609x862 , 1407771571818.gif )

But like, man, what if it's just how our puny human minds THINK the numbers work; but they don't actually work that way at all. There's probably like, aliens out there that say like, 1+5=blargnip. We could have it all wrong, man. There's absolutely no way to tell if our math is the right math because we're humans man.
Alien math could be like way different. Like, triangles with seven sides or something I don't know. There's just no such thing as a concept that exists independent of opinion and culture.

You guys should take some liberal arts courses, it'll open your eyes.

Anonymous 14/08/15(Fri)07:50 No. 15825 ID: c1bebf


Numbers are based initially on the observation that you can count objects. Any alien entity so divorced from our frame of existence that they don't relate to solid objects in the same way we do will never observe us or be able to communicate with us in any way, so it's a moot point. In other words, you wrong, dude. Any alien being we could be able to encounter will be dealing with the same physical universe we do, and will necessarily be able to relate to concepts based on that physical world, like if you have a gooblatz with BINGBINGBING gobblefertzis growing on it, and BING falls off, there are still be BINGBING left.

Anonymous 14/08/15(Fri)12:39 No. 15826 ID: 789203

And, more abstract mathematical objects (e.g. an infinite sum of increasingly small elements) are based entirely on axiomatizations of those initial intuitions. If the aliens axiomatize their perceptions the same way we do, they'll necessarily arrive at the same conclusions. If they don't, then their conclusions are not relatable to our own, in the same way that you can't use Pythagoras's theorem to prove or disprove the infiniteness of prime numbers.

help wer 14/06/27(Fri)00:24 No. 15749 ID: ad7ee9 [Reply]

File 140382149423.jpg - (0.96MB , 2048x1536 , 20140626_205905.jpg )

What the fuck is this!!!

2 posts omitted. Click Reply to view.
Anonymous 14/06/27(Fri)09:45 No. 15752 ID: 856bb6

File 140385512411.jpg - (28.46KB , 503x345 , IMG_155644668428229.jpg )

H2O nigga. It's the only stuff remaining. I do A2 chemistry. H2O (commonly known as water) is a common product in many reactions.

Anonymous 14/07/25(Fri)13:24 No. 15764 ID: 52a81c

what is 'flying materials?'

Anonymous 14/08/14(Thu)13:52 No. 15823 ID: 9c94f7

i dont even study chemistry and this is pretty obvious, even to me

Anti-Aging Anonymous 14/07/31(Thu)06:00 No. 15779 ID: 800849 [Reply]

File 140677920234.jpg - (370.63KB , 850x565 , iStock_000010280186Small.jpg )

Can we get a thread on anti-aging and lengthening lifespans?

Any possibilities, and problems with those possibilities. And ways to get around said problems. And more problems. And repeat. Until we get to even a slightly plausible solution.

Then, maybe somebody like Qin Shi Huang will say, "Hey, maybe if we try to make this better, it will work in a few thousand years!"

First time on /sci/, so bear with me.
Anyway's, lets go?

9 posts and 1 image omitted. Click Reply to view.
Anonymous 14/08/11(Mon)18:24 No. 15814 ID: d9f5aa

though it is interesting how to punish the faggot magician.
he played russian roulette, but it was his own choice and he was not blackmailed into it, so what he did should be as legal as suicide or doing drugs.

he was pretty retarded though. i don't like stories where people act like lobotomy victimes.

Anonymous 14/08/12(Tue)10:39 No. 15818 ID: 789203

>it doesn't just transport him, it creates a perfect clone with the same memories that appears at the secondary location when the device is tested. However, because one of the clones is then killed, we never find out if the machine creates a copy and transports it, or if the original is transported and the machine leaves a copy behind.
>He can never know if, after he presses the button on the machine, if he is the one that will be in the tank, or in "the prestige".
This doesn't make sense. The point of the cloning-type teleporter is that making true teleporters is hard. If the device is a teleporter, why bother making a clone at all? Why not have it just teleport you to the other end every time?
The alternative is that the device is not a teleporter, in which case the user at the source does die by drowning, 100% of the time.

>uhm there is most likely no such thing as "you".
>"you" is merely the result of an analog computer's computations
I'd say it's more correct to say that I exist as a part of the computation itself, rather than it's result. The result is what other people perceive as my external behavior.

>the atoms may be different but the personalities will still be the same. there is no logical reason to call the person consisting of the original molecules anymore real than the copy.
>if you upload your mind to a computer then you will be alive twice until one of you dies.
But you and they are necessarily able to tell which one is the original and which one isn't. One of them came out of the "output" door and the one other one didn't. One of them ended up hosted on a computer and the other one didn't. Their respective consciousnesses are separate and distinguishable.

Matchbox Prince 14/08/12(Tue)12:54 No. 15819 ID: 2f260d


The machine was an imperfect invention, and Tesla didn't even know, himself, how it worked — just that it did work. As I mentioned, it was never revealed whether the machine: 1) Transported the original subject, leaving behind data which reassembled itself into a clone, or 2) Beamed the data to the secondary location, creating a clone there from it, while the original subject didn't move at all.

An interesting plot the movie could have explored was if it functioned via method 2, but each time the data was copied and a new body made, a tiny portion would be lost or corrupted, perhaps just a few atoms or molecules (like jpeg compression artifacts). This would cause each subsequent clone to be a little more insane and crippled than the last. But I digress...

>the atoms may be different but the personalities will still be the same. there is no logical reason to call the person consisting of the original molecules anymore real than the copy.

No. If that were the case, then a cloned person (or to be realistic, a newborn twin) would see from two sets of eyes at once. Whatever a human being's consciousness is, it sits firmly attached to one single ball of wrinkled fat inside their skull until said ball is destroyed or deprived of oxygen long enough to rot. From what we know, discounting hallucinations of people who get to the point where it's starting to rot a little, it can go nowhere else.

I could add in a recent counter-theory I've had about a singular universal consciousness through shared memory, and how it can be a rational reason for accepting the possibility of metaphysical solipsism, but it doesn't really belong here.

jdawg 14/08/12(Tue)06:23 No. 15817 ID: 18c102 [Reply]

Youtube - Toggle Video
  Somebody stole my phone at Walmart in Angleton, TX.... It is vital for my work. My number is 9792858654 through Verizon. There will be a reward to anyone that can help me find it.

Cryptoforums.net Technology Forum Cryptoforums.net Technology Forum 14/05/13(Tue)10:25 No. 15656 ID: 288b60 [Reply]

File 139996955137.png - (8.43KB , 82x77 , CF-logo.png )

Hello chans of the internet. We at https://cryptoforums.net have created a MyBB forum dedicated to the discussion of things like Bitcoin, Privacy, Security, Cryptography, GNU/Linux, Philosophy, Politics, Freedom, Cryptocurrency, Hacking and many other general subjects. We are currently in our early stages and we want to invite more members. If you like any of those subjects you should come check us out! We also respect anyone's opinion even if negative so give us all your positive/negative support/criticism!

7 posts omitted. Click Reply to view.
Anonymous 14/07/31(Thu)05:04 No. 15773 ID: 800849

Legally, the government can't catalog information about all the peoplez of the world. But, they found a way around that.
Then, they made it look like everyone was against it. And, more than likely, kept doing it.

Anonymous 14/08/11(Mon)18:38 No. 15815 ID: d9f5aa

the joke's getting old, shillfag.

OP your forum would be a lot more appealing if it didn't require an email.
trashmail makes it easy but waiting for the email to arrive is a fucking dealbraker.
I'd probably rather enter a fucking google recaptcha and have my everchanging dynamic IP logged by some useless waste-of-money agency than wait for a shitty activation mail (and possibly still get logged if my ISP or trashmail provider is sharing data as much as google does).

Anonymous 14/08/11(Mon)18:39 No. 15816 ID: d9f5aa

>>15662, not 199869 obv.

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.

6 posts and 1 image omitted. Click Reply to view.
Anonymous 14/07/31(Thu)05:53 No. 15777 ID: 800849

How about, while focusing on shorter voyages, we work on longer lifespans and stuff. Like, anti-aging and stuff would probably be faster than changing the laws of physics.

Anonymous 14/07/31(Thu)05:53 No. 15778 ID: 800849

How about, while focusing on shorter voyages, we work on longer lifespans and stuff. Like, anti-aging and stuff would probably be faster than changing the laws of physics.

Anonymous 14/08/04(Mon)13:26 No. 15806 ID: 2f260d

By the time we get there, we probably could have just terraformed Mars.

Delete post []
Report post