/sci/ - Science & Math

[Anonymous No.1206114]

Sup /sci/? How about we just have a knowledge thread. Show off what you know by typing up stuff on a subject of your choosing.

I'll talk about heart attacks.

Now, you guys know that a heart attack is bad. To understand exactly what's going on, let's talk about the heart. The heart, like all muscles, needs a blood supply. You may be wondering "Well, blood goes through the heart all the time. Problem solved". However, there are two reasons why that's wrong. First off, the right atrium and ventricle both have deoxygenated blood in them, so obviously that's not going to help. Secondly, the blood in that case would only help the endocardium, a thin layer of tissue on the inside of the heart. The heart is not just one giant muscle. It's made of fat, muscle, and epithelial tissues. All of those need blood. Now, as blood leaves the aorta, there are three aortic sinuses that are on the insides of the aortic valve. Two of those become coronary arteries (I don't know about the third) that supply blood to the muscles and everything else in the heart. These feed into the cardiac veins, which ends up in the right atria.

To be continued (fuck you field too long).

[Anonymous No.1206115]

Now, as you know, fat is bad for you. It builds up in your arteries, and that's not good. If it builds up in the coronary arteries, that's fucking bad. As blood flows through, the fat could end up partially blocking blood flow to the muscles of the heart. This is a condition called angina pectoris. This is normally not fatal, and the heart can recover from it. However, this means that a heart attack (aka myocardial infarction (myocardium=muscle layer of heart, infarction=forming of an infarct (area of dead tissue))) is right around the corner. In a heart attack, the blood flow is completely blocked, so no blood gets through. This ends up killing muscle cells, so you really don't recover from this. This is why a heart attack is so bad, because it cripples your heart, long after it happens (assuming you live).

Also, you guys probably know that a heart attack is associated with pain in the shoulder and left arm. However, the arm isn't there. This is called referred pain. Basically, since nerves from the shoulder and left arm meet with the heart on the way to the brain, the brain sometimes thinks the pain is coming from those areas.

If anyone is interested, I could go into other potential consequences a little bit.

Also, yes, I did type this all up.

tl;dr: There isn't one. Read it you lazy bastard and get educated.

[Anonymous No.1206118]

Id like to talk about gene centered evolution. I assume were all in an academic environment and can agree evolution happens, correct? (insert laughter)
The fact is, there is much dispute about natural selection's reach. It undoubtably effects organisms on an individual level; if the weather is colder and I have a mutation for a thicker fur coat, I will be selected for. But can natural selection act on other units, such as cells? what about groups or clades? I, as many have, propose it can act on genes. Genes may be the most irreducible unit of natural selection, in that any smaller, and natural selection begins to break down. Genes are selected for on the basis of actual physical length, usefulness, and their general effect on their carrier.

ill stop because ive written alot and havent said much.
and yes ive just read the selfish gene

[Anonymous No.1206120]

Fuck, fine, I'll talk a little about the defibrillator.

So, when I said that, did you think "Oh, that's used if someone is flat-lining"? If so, you're wrong. That's all Hollywood. CPR, I believe, is the only helpful thing in that case. So, when is a defibrillator used? Well, after/during a heart attack, the heart is stopped. The SA (sinoatrial) node is the natural pacemaker of the heart, which sends out signals to the AV (atrioventricular) node, which then go to Purkinje fibers. These impulses control the rhythm of the heart.

If the heart is stopped, another heart cell can start contracting, and start it's own rhythm, not necessarily the one the heart needs to work. The heart becomes a mess of random contractions, and nothing gets done. This is very, very fucking bad. This is arrhythmia. This is fixed by, you guessed it, the defibrillator. As you know, this has a very fucking strong voltage. The reason it is not used if the patient has flat-lined is because of how it works. The defibrillator sends out a shock that overrides the heart entirely, stopping it. See why using it on a flat-lining patient is stupid?

So, the defibrillator shocks the heart, and it stops. The reason this is done is to help the SA node. Before the shock, it has no fucking control over the heart. If everything is stopped, it has a chance to take control again and establish a normal rhythm. Multiple shocks may be required for it to get back in control. Think of it as the SA node fighting a battle against a crazed army, and the defibrillator gives everyone shell shock, hopefully allowing the SA node to recover the fastest.

NOW YOU KNOW.

[Anonymous No.1206124]

i thought engineers WERE scientists...

[Anonymous No.1206125]

Psychfag in the house.

Serotonin Syndrome is a potentially fatal condition caused by mixing anti-depressants with other drugs, causing an overload of serotonin the brain. SS can be entirely asymptomatic, but when it becomes fatal, symptoms can be both psychological (hypervigilance) and physical (shock). SS usually causes death by hyperthermia, raising the body temperature above 106 degrees F.

There is no test to diagnose SS, so it can only be identified by the pattern of symptoms.

The most famous case of SS was Libby Zion, who was overprescribed anti-depressants by doctors working long hours, and presumably out of their minds. This case resulted in work limits on medical professionals.

[Anonymous No.1206138]

Econofag here, presenting some info on the concept of specialisation:

All our economic progress stems from the division of labour (specialisation). Back in the times when people lived in tribes, they hardly specialised. Information was symmetric among everyone (meaning that everyone had the same knowledge) and people were unable to greatly increase their productivity, due to the fact that they had to produce multiple goods, instead of focusing on the production of one good. (North, 1990)

Adam Smith (1776) recognised that there are three reasons why productivity increases when specialisation occurs:
(1) Increase in dexterity. If you make one specific part all day long, for many years, you'll be able to do it way more quickly than any other person, because you're so familiar with its production process; you've probably found the quickest possible way to do things, while people who are not that familiar with this production process haven't figured that out yet.
(2) You don't have to spend time switching between jobs. Imagine that you would have to fulfil the role of part-time accountant, foreman, marketing guy, etcetera, instead of having one specific job. You lose time by moving from one workplace to another. Furthermore, your mind is probably not really set on switching jobs. Therefore, focusing one one job makes you more productive
(3) People who work on one specific task are likely to figure out, for instance, machinery that reduces the effort required to produce stuff. In other words, the inputs required for a good are smaller than before, meaning that there is an increase in productivity.

(1/2)

[Anonymous No.1206139]

Why are we doing this again? At least post some original info.

[Anonymous No.1206143]

A downside of this division of labour is that, contrary to the primitive tribe, information is now asymmetric. This means that, due to the opportunistic behaviour of people, we now incur so-called transaction costs. Transaction costs include the costs of setting up laws and regulations, enforcing these rules, searching for information about reliable partners in trade, setting up contracts, etcetera. Transaction costs hardly occurred during the tribal era, because many people either provided for their own goods or had a very good idea of whom to trade with (since they were rather close-knit communities). North and Wallis (1986) showed that over 50% of GNP comes from transaction services. In other words, roughly 50% of what is supposed to be a measure of a country's welfare is wasted on looking for information, making contracts, etc.
An obvious implication of this is that while Western countries are of course a lot richer than Third World countries, the difference is smaller than what we might have expected.

All of these costs would, of course, be gone if people were 100% trustworthy and everyone would have perfect information. Some people argue that the internet can take care of the perfect-information problem, but this is not necessarily the case. Since it's so much easier to find information, we also spend a lot more time on searching for information, so that the transaction costs increase. On the other hand, this information search allows us to make better decisions. It's impossible, or at least very hard, to do a proper cost-benefit analysis to see how profitable it is to use the internet.

Neoclassical economics has the extremely unrealistic assumption that there are no transaction costs, or that they are in any case negligible. Since they do occur, it would seem that a large portion of neoclassical theory is outdated and needs to be replaced with something that actually represents reality.

(2/2)

[Anonymous No.1206145]

>>1206120
cool

[Anonymous No.1206147]

>>1206139

Stop being a cry baby. If you want original info then post it. I'm just trying to kick start it.

Lead, follow, or get out of the fucking way.

[Anonymous No.1206149]

I endorse the OP, because it is accurate medically and devoid of bullshit.

Another thing I'd like to say is that the difference between an angina pectoris attack and a heart attack is not as clear and as fuzzy as people think.

Basically, coronary artery clogs can be transient or intransient. You feel a searing pain either way, and your heart muscle is devoid of oxygen either way, the only difference is an angina attack is transient and blood flow is restored, preventing permanent damage. A cardiac attack is when the blood flow obstruction lasts over 30 minutes.

If you take nitroglycerin in the first 15 minutes of the attack, you stand a good chance of widening the arteries enough to get the blood flowing and avoiding the attack becoming a heart attack. Naturally there is a limit to what nitroglycerin can do if your coronaries are excessively clogged.

tl;dr get of your lazy fat ass and start shaping up.

Oh and another thing amerifags seem ignorant of : you can actually eat fatty foods without too much risk, as long as you burn it off later. Of course it is not as healthy as eating ultra-dietary foods, but keep in mind that 70% of all cholesterol is endogenous (produced inside the body) regardless of what you eat.

Oh, and cholesterol isn't really the bad guy everyone seems to think it is. Cholesterols are vitally important particles doing their metabolic job, which is ferrying fats around the organism. Without cholesterol you'd be fucking dead. It's just that if there is more "bad cholesterol" (LDL) it means there is a fuckload of fats to ferry around. So don't blame the garbage men for doing their job. Instead, litter less.

[Anonymous No.1206151]

Whoa, deja vu.

Oh wait, you're just copy pasting shit. Post some original stuff instead of typing up basic stuff like that.

[Anonymous No.1206153]

>>1206151
see
>>1206147

[Anonymous No.1206154]

>>1206114

how bout you be a dear and RS that fucking textbook

[Anonymous No.1206177]

>>1206154

Project R

[Anonymous No.1206250]

Someone post some good info

[Anonymous No.1206335]

A pint of Guinness can be substituted for a glass filled with marmite and topped with shaving foam. This has the added advantage of tasting better.

[Anonymous No.1206625]

1/2
Another Psychfag in the house.

So you all hear that stress causes you to get sick, but what is stress and why? You have your sympathetic nervous system (SNS) and your parasympathetic nervous system (PNS), they work together. The first is the one you use when a bear with rabies and threatening you, your heart rate increases, adrenaline courses through the body, blood pressure goes up, respiratory rate increases, so on etc; whenever the SNS is in effect, you are stressed. The parasympathetic nervous system (PNS) is the part of the nervous system is the system that prepares the body for future bear encounters (creates and stores adrenaline, rest the body). Now this is what the SNS and PNS was designed for, back in caveman days when you actually had bears to run from.
Nowadays we have very few bear encounters, and most of our SNS kicks in when the boss yells at us or we are cutting it close to making a deadline. Now stress isn't a bad thing short term, stress is actually very, very good short term (heart rate rises, gets a good exercise). It is when this stress lasts long term that we get stories of cancer being made worse by stress. The body is working so hard but for no reason, the heart beats fast for no reason, wasting energy, you take in every calorie of every bite of food you take, making you fat.

[Anonymous No.1206632]

2/2
Some of you may be thinking "okayyyyyyyy... so what?" But this shows exactly how placebo pills work. If you have a neck ache, stomach problems, high cholesterol, a doctor will most likely supply you with a placebo. Many don't know WHY these work, just that they DO work. But it is very simple
1. Patient has a disease brought on by stress
2. Sees a doctor
3. Doctor tells patient to calm down and that these pills will fix anything (even though the doctor knows they are placebos)
4. Patient stops worrying about the illness, stress goes down, illness goes away.

[Anonymous No.1207158]

>>1206625
>Now this is what the SNS and PNS was designed for, back in caveman days
>designed

Careful there anon

[Anonymous No.1208632]

bamf

[Anonymous No.1209629]

bump

[Anonymous No.1211367]

>>1207158
oops sorry = /

but this is what it purpose.. err, function... god dammit... SNS AND PNS EVOLVED TO BECOME COMMON TRAITS BECAUSE IT FUCKING WORKS WELL AS SHIT

[1|1 No.1211475]

Will dump information, if requested.

[1|1 No.1211483]

[Anonymous No.1211489]

>>1211483
im ok with this

[1|1 No.1211495]

[1|1 No.1211501]

[1|1 No.1211503]

[Anonymous No.1211506]

Mathfag here.

I'd like to talk about probability. A common logical fallacy often uses the following notion: Suppose event A occurs, and the probabality of event A is extremely. Therefore, X caused A (where X is a divine force etc.).

The mistake made is that events with vanishingly low probability happen all the time. For example, suppose you are dealt a hand in a game of poker. The probability you would've gotten this hand a priori is extremely low. Or if you like, imagine an elimination match of coin tossing with an arbitrarily large number of players; the winner a priori has an extremely low chance of winning. The point is that you must be dealt SOME hand in poker (and someone must win at coin tossing). Therefore, giving deep meaning to things with low probabilities is absurd. So then how can probability be useful if things with low probabilities happen all the time? The answer is in experiment. Probability is only a model; reality fundamentally has nothing to do with probability (i.e. nothing in reality is REALLY following any sort of random number distribution). So we write the probability of getting a hand in poker and try simulations of giving out hands. Either the probability converges in the limit, or something is wrong with our model (note: this is the frequentist's interpretation of probability).

[CHILI GOES IN ALL FIELDS No.1211548]

>>1206632
>>1206625
I think I read this in a psychology magazine. Great article

[Anonymous No.1211611]

Physicsfag here. I'll try to make sure this is right (rwriting from memory)
------
Black holes are super-dense objects containing a singularity at the center. In Einsteins model of the universe (read: spacetime), this singularity concentrates mass so greatly that it bends spacetime enough that nothing, not even light, can escape (sort of). Because of the nature of singularities, they are surrounded by an 'event horizon', essentially a point of no return. Imagine rafting over a waterfall. Eventually there is a point that no matter what, you're going down the fucking waterfall. That is what the event horizon is like. Once you are over it, you are going into the black hole.
The time dilation effect of black holes is caused by their intense gravity. If you have read Einstein's book, you know that acceleration and gravity are the same thing. And it's been scientifically proven that acceleration slows down time. this proves that the gravity of the black holes is what causes the time difference between the falling thing and the observer.
Black holes are not truly black. Stephen hawking famously proved (and won a Nobel? I forget) that they are a fraction of a degree above absolute zero. This is because of the nature of the event horizon. Remember that? While, in quantum mechanics, things called virtual particles are constantly created in pairs and recombine and are annihilated. However, if this happens near the event horizon of a hole one particle may 'fall in' while the other escapes. This would be (if we had actually found a proven black hole yet) detected as a minuscule amount of radiation.

[Anonymous No.1211639]

Wow, best thread I've seen in a while. Thanks OP!

Deep brain stimulation is an interesting new treatment for certain neurological disorders, such as Parkinson's and chronic pain or tremors. It involves inserting a lead into various parts of the brain, such as the Subthalamic nucleus or the GPi, in the case of Parkinson's. The leads act as a pacemaker for the brain, and while it is unclear how exactly it works, the results can be very drastic for individuals who are drug resistant. It has also been shown to work for major depression. I know someone who programs these things, and she has some interesting stories about what can happen, although the most interesting is the difference it can make. One individual, when it was turned off, was a drooling mess. When it was activated, he had a slight stutter.

[Anonymous No.1211718]

Awesome! This thread's back! Here's my contribution on sex determination systems:

As we all know, our sex/gender is determined by the X/Y chromosomes (XX is female, XY is male). Did you know, however, that this is not always the case?

For instance, there is another type of sex-determination system out there, the ZW system. This can be considered to be the opposite of the XY system - ZZ is male, ZW is female. This system is found in birds, some fish and crustaceans.

Some reptiles use a temperature-based system, where depending on the temperature, offspring hatch as male or female.

Lastly, some insects use a system based around how many chromosomes they have. Let's back up a bit so I can explain this more.
Humans have 23 pairs of chromosomes (46 total). In our eggs and sperm (gametes), there are only 23 chromosomes in the nucleus, so 'half a genome'. Gametes are thus haploid cells. When an egg is fertilized by sperm, the resulting zygote now has its proper 23 pairs of chromosomes and is a diploid cell. In insects, haploid, unfertilized eggs develop into males, while fertilized eggs become females.

[Anonymous No.1212057]

Bump!

[Anonymous No.1212071]

>>1211475

Where would 'old age' be on there?

[Anonymous No.1212093]

Seeing as some people... i wouldn't say liked, but certainly reacted to the info i gave about Prion diseases, time for a little more bio-scares.

Let me tell you about Toxoplasmosa gondii: A parasite (not a worm, a helminth) that is found the world over in domestic pets. What happens is the parasite is ingested by a cat, from the soil or grass or other contaminated food (it can survive outside of a host for actual years, something like hibernation except then the bear wakes up inside you). It reactivates in the cat stomach, reproducing and going unnoticed, eventually excreted. Along comes a mouse or a rat to nibble away on the cat crap because, well, that's what they do. Inside of them, gondii again reawakens, but it doesn't go for the gut. It goes for the brain. Exerting tiny amounts of control over its host, the mouse finds itself attracted to the smell of cat urine. It is compelled to go to an area where it is certain a cat has been present, and very probably will return. And it does. Cat eats mouse, ingesting another generation of parasites. There's a species of worms in the river-snails Ganges which make peoples feet feel like they're on fire, so they go back to the river to cool off, in a similar fashion. But one last thing about gondii:

It's in about 50% of the human populaton.

[Anonymous No.1212127]

>>1212071
No-ones died of Old Age since 1956, i think. Since then, it's been classed as coronary failure and such.

[Anonymous No.1212148]

>>1212093
The results of that parasite are very interesting- it makes women more interesting and wild, and men more dull. I'm terrified of it.

[Anonymous No.1212193]

I smell a samefag

[Anonymous No.1212199]

>>1212148
oh snap

[Anonymous No.1212200]

>>1212193
maybe, but its its not a troll thread, so whatever
(bump)

[Anonymous No.1212416]

who can talk about eye surgery? how does it work and if it's effective.

[Anonymous No.1212482]

>>1212093
It's less than that in developed countries, I habeeb?

[Anonymous No.1213446]

>>1212482

That's the case for a fair chunk of parasites last I checked. Better hygeine in people and food.

To go off on a slight tangent - the lack of parasites in more developed countries has been theorized to be partly responsible for the higher allergy rates seen in more developed countries. To put it in simple terms, without a 'proper target', the immune system starts going after innocuous things like peanut proteins, pollen etc. If anyone would like the more detailed explanation, speak up!

[Anonymous No.1214259]

BUMP FOR MORE PSYCH FACTS

[Anonymous No.1214297]

To make an apple pie from scratch, you must first create the universe

[Anonymous No.1214490]

Niggers are Niggers, they nigger a lot

[sage No.1214588]

>>1214259

Seconded.

[Anonymous No.1215593]

Bumping! I want to see some Chem stuff!

[Anonymous No.1216248]

Here's a little (heavily paraphrased) blurb I picked up from Jared Diamond's kickass book Guns, Germs, and Steel (Winner if the Pulitzer Prize in '97).


People believe that the origin of society was aptly described by Thomas Hobbes with the concept of the Social Contract - an agreement between people to organize in order to promote mutual interests and for the sake of safety (Cicero also theorized that the cause of which was the first rhetorician, but that is venturing too far into philosophy (though it is still fascinating)).

Anthropologists, though, assert that this account of societal evolution is merely romanticized - social and political organization actually arose from people realizing they needed to distribute necessities (mainly fresh water) utilizing logistics and not a simple system of "first come, first serve". Nomadic tribes became more sedentary around major rivers and became bureaucratized merely for the distribution of goods - it had little to do with a passion for politics. This gave rise to the Neolithic Era (deviation from nomadism into agriculture) and thus modern civilization.

[melikes No.1216815]

PLEASE ARCHIVE THIS THREAD!

[Anonymous No.1216857]

I give you the weather

[Anonymous No.1216874]

>>1216857
sorry wrong one

[Anonymous No.1216875]

>>1206114
oh look physics 3rd edition

that book doesn't piss me off, however of the flip side if you have the hard back version you can throw it at someone and believe you me they wont get back up

[Anonymous No.1217758]

>>1216874
saved

[Anonymous No.1217769]

>>1206632
>>1206625
I posted these, forgot to mention that this is the reason meditation and yoga are "cure-alls" and gives some support to "the human body can heal on its own" idea that hippies have. The human body can only heal what damage and disease it has brought on itself.

[Anonymous No.1217834]

>>1211475
Is it me, or do those fractions not appear to converge to unity, i.e. the areas aren't even close to filling up to the larger circle?

[TheLionHearted !HAGYQOveO. No.1217879]

>>1217834
They're not, but then again there are many more ways one may die that have simply been excluded.

[Anonymous No.1217933]

this thread is Vaginas!

[Anonymous No.1219198]

Evolution of the eye

...and bump.

[Anonymous No.1219734]

more guys, we all contributed, your turn = (

[Anonymous No.1219767]

>>1206125
Serotonin Syndrome can also be induced by giving a patient Demerol while he/she is on an MAO Inhibitor. THE MOAR YOU KNOW