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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
15270

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:

http://ebookee.org/index.php?tag=7

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.


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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 14/09/08(Mon)10:07 No. 15872 ID: 84146f [Reply]
15872

File 141016364114.jpg - (21.14KB , 521x161 , slui.jpg )

I need a product key activator for Windows 7 Ultimate SP1 ASAP. I tried activating it manually, but I receive this error message.


>>
sage Dumb_Nigger 14/09/08(Mon)11:24 No. 15873 ID: b2bc2a

try google, faggot


>>
Anonymous 14/09/16(Tue)14:44 No. 15876 ID: a29f36

Buy a real Windows 7 Ult key faggot




Anonymous 14/04/24(Thu)21:56 No. 15638 ID: cf7d56 [Reply]
15638

File 139836940417.jpg - (32.02KB , 599x399 , image.jpg )

Faggotry is hormonal imbalance. It has to be. What else could it be besides environmental trauma?


22 posts omitted. Click Reply to view.
>>
Anonymous 14/09/08(Mon)08:10 No. 15871 ID: 789203

>>15870
>For example, being intelligent and/or social on its own doesn't provide much advantages as to being able to adapt to an unstable environment. Going down the list of most intelligent animals (excepting for the moment humans) is like taking a trip down the endangered species list.
Well, being smart isn't going to give you many advantages if you're going up against something smarter and more powerful than yourself. You can't outthink a bulldozer tearing through your home, or a gun shooting you in the face.
Being smart can help you figure out safer ways to get food. We devote over 1/5 of our energy expenditure to brain upkeep. Compare to around 1/20 for most other vertebrates. Having such large brains would put us at a significant disadvantage if they weren't able to compensate by providing more food and generally being better able to the body safe.

>Meanwhile, species like ants and bacteria that don't even have brains as we think of them thrive in every environment on Earth.
Just imagine how terrifying they'd be if they were smarter than us!

>The only reason human intelligence and cooperative power has provided an evolutionary edge is because it (after a few hundred-thousand years of doing nothing in particular) suddenly and exponentially enabled them to alter the environment to suit their needs. However, the same technology that gives humans long, (re)productive lives as medical care, perfect food, and air conditioning has also lead to global warming, which might be the thing that kills us all.
And? If that was our ultimate fate, it would just show that evolution is a sub-optimal algorithm, not that intelligence doesn't make sense evolutionarily.


>>
Anonymous 14/09/10(Wed)03:54 No. 15874 ID: 00718f

>hormonal imbalance
I believe not in full grown people but in the womb enough testosterone was present for Y chromosomes etc but not enough to fully convert the brain leaving a more feminine physios


>>
Matchbox Prince 14/09/11(Thu)10:04 No. 15875 ID: 2f260d

>>15874

It's a myth that homosexuals have less testosterone; they actually tend to have more. Also, while the brains of homosexual men work more like heterosexual women in certain ways when looked at with PET or fMRI scans, the statistical difference is so insignificant (differences between individuals are far larger than the differences between the groups) that it's really irrelevant. Any association of homosexual men with feminine traits is culturally generated and exclusive to the modern, Western world.




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

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.


19 posts and 4 images omitted. Click Reply to view.
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Anonymous 14/09/06(Sat)01:22 No. 15864 ID: 3c414f

>>15857

>Oh, well, sign me the fuck up.

Sign yourself up, you lazy fuck.


>>
PlutoniumBoss!Y1SVQJ54eA 14/09/06(Sat)08:59 No. 15867 ID: c1bebf

>>15851

While it's true that the "Habitable Zone" model excludes many places where life might exist, its purpose is simply to refine search parameters. The universe is a pretty big place[citation needed]. The point of the Habitable Zone is not to say 'this is the only kind of place where life will be found.' Rather, it simply says 'this is the sort of place where we are likely to most easily find life in a form we can readily recognize.'


>>
Anonymous 14/09/06(Sat)17:24 No. 15869 ID: 3c414f
15869

File 141001709447.jpg - (160.02KB , 500x666 , 1295238273223.jpg )

>>15867
Oh, I understand. I guess what bugs me is the 'popsci' aspect of it all. It over simplifies the concept to the point of absurdity, take the phrase "goldy locks zone", grinds my gears it does.
I also understand that it is a way to explain the concept to those whit little or no science background, but still the gross over simplification gets me. It's so much more fun and satisfying to think about it in a more real, practical sense.

being a man of science (envr consultant turned highschool teacher) the oversimplification has always bugged me, the burden of smart people.




Anonymous 14/09/05(Fri)02:34 No. 15861 ID: 9db7e9 [Reply]
15861

File 140987727820.jpg - (233.09KB , 1240x1754 , 981.jpg )

I plan on doing a reductive amination (ketone + nitromethane) in the next few weeks, using Al + Ga metals.
Does anyone have any useful tips on this reaction?
(Reference: "Reductions in Organic Chemistry", Milos Hudlicky, Prof. Chem., Virginia Polytech. + state university).




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

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?


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Anonymous 14/09/04(Thu)08:17 No. 15858 ID: aaad3e
15858

File 140981147295.png - (232.73KB , 1280x906 , tumblr_nba8kl4vDW1tkkdcvo4_1280.png )

If you don't age, how will you grow?


>>
Anonymous 14/09/04(Thu)09:06 No. 15859 ID: 1b02b6

>>15858
They're talking physically, not mentally. Everything is about the exterior surface, and not the quality within. Stop me before I begin a rant accompanied with a flush of tears running down my face


>>
Matchbox Prince 14/09/05(Fri)00:01 No. 15860 ID: 2f260d

>>15858

Maturation and aging are different processes. There's a reason why most depictions of immortal beings has them in the prime of their life.




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

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

is .999...=1?


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Anonymous 14/08/15(Fri)06:46 No. 15824 ID: c85029
15824

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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

>>15824

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

>>15824
>>15825
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.




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

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/


2 posts and 1 image omitted. Click Reply to view.
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Anonymous 14/08/23(Sat)14:17 No. 15841 ID: 080683

>>15837
TL;DR:
The function should evaluate not probability of individual passing genes, but gene pool's resulting survival.


>>
Anonymous 14/08/23(Sat)14:32 No. 15842 ID: e3000c

Of separate note is the fact (apparently) that competition is by no means the goal of evolution. The "goal" appears to be simply replication, and competition makes sense only when different genetic forces use same limited resources.


>>
Anonymous 14/08/24(Sun)01:07 No. 15843 ID: 789203

>>15840
>Thanks, that makes sense, although it is a behaviour observed in short-running, low count computer based genetic algorithms, no?
>This short-sightedness might not still be in effect in a superhuge pool like Earth's biosphere for very common and long-running traits, as there might be plenty of opportunity for evolution to go outside local maxima because of sheer number of attempts.
Depending on the maximum possible Hamming distance (given two bit strings, for each bit that's different to the counterpart bit in the same position, add 1 to the distance) between two generations of the algorithm after mutation and the slope of the function, it's possible to prove that some algorithms will never escape some peaks after reaching it.
In other words, if mutations are too conservative and selective pressures are too high, it's possible that once some peaks are reached, the only way out is extinction.
It's similar to the prisoner's dilemma. If just one player will cooperate, they'll get screwed. Either everyone cooperates or the one that does cooperate is much more powerful than all the other players combined.
A possible way out is by ignoring DNA. For example, the optimal thing for us humans to do would be to disregard any suffering that we may cause lab animals and just do whatever. Because of ethics, we don't do that.

>15841
>The function should evaluate not probability of individual passing genes, but gene pool's resulting survival.
That may kind of be what it does. What I was getting at is that the range of possible solutions that optimize individual success is a subdomain of the range of possible solutions that optimize general success (and average individual success as a side-effect).




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

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:

http://img.ie/oka82.png

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.

Follow?

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


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

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


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Matchbox Prince 14/08/22(Fri)23:26 No. 15835 ID: 2f260d

>>15828

1. Source?
2. Doesn't take into account that the only people stupid enough to google-search for childporn are preteens, themselves.


>>
Anonymous 14/08/23(Sat)03:10 No. 15838 ID: 597595

>>15835

1. The book "One Billion Wicked Thoughts".
2. I think young boys generally prefer older women, at least I did when I was young.




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

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

Kickstarter campaign to purchase Lunar Meteorite

https://www.kickstarter.com/projects/1141594225/lunar-meteorite-boxes




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