/sci/ - Science & Math

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Anonymous Mon Jun 14 03:48:57 2010 No.1181171 [Reply] [Original]

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 Mon Jun 14 03:48:57 2010 No.1181172

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 Mon Jun 14 03:51:57 2010 No.1181182 Bump I put a lot of effort into making something that isn't atheism vs. christianity.

>>	Anonymous Mon Jun 14 03:53:57 2010 No.1181192 i'm interested

>>	Anonymous Mon Jun 14 03:54:57 2010 No.1181200 >>1181192 In the other consequence? Well, it's about one thing that can happen during/after a heart attack.

>>	Anonymous Mon Jun 14 03:56:57 2010 No.1181208 Come on /sci/, don't leave me alone.

>>	Anonymous Mon Jun 14 03:58:57 2010 No.1181217 >>1181208 ugh ill make one hang on...let me think

Anonymous Mon Jun 14 04:06:57 2010 No.1181244

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 Mon Jun 14 04:06:57 2010 No.1181246 >>1181208 Way too drunk to write anything coherent right now, but let me say that I approve of this and I wish most /sci/ threads were like this.

>>	Anonymous Mon Jun 14 04:06:57 2010 No.1181248 Dammit /sci/. I try to make an interesting thread, and you leave me with nothing. And soon, you will be bitching about the atheist vs. christianity threads. Eh, I've saved all of this. I'll be back later.

>>	Anonymous Mon Jun 14 04:09:57 2010 No.1181265 >>1181248 I encourage you to continue making interesting threads, but I've got to go to sleep now. Keep up the good work.

Anonymous Mon Jun 14 04:10:57 2010 No.1181268

>>1181244
cont...
the best way to propose this effect is through Richard Dawkins' selfish gene hypothesis. To oversimplify, yes, it is what youre thinking. Genes are biased toward actions that will preserve themselves. This makes sense, because anyone can tell you that genes have only one purpose- to replicate. This doesnt take much thinking. A gene wants to survive, so it "tells" its host to run if being chased by a predator. but what i think is most interesting is how this theory is applied to examples of altruism.

will use this post as a bump

>>	Anonymous Mon Jun 14 04:17:57 2010 No.1181298 tl;dr

>>	Anonymous Mon Jun 14 04:18:57 2010 No.1181301 dont have anything. but im interested

>>	Anonymous Mon Jun 14 04:19:57 2010 No.1181308 You know /sci/, these threads only work if there's more than 2 people who give a fuck.

>>	Anonymous Mon Jun 14 04:22:57 2010 No.1181320 >>1181248 dont get mad bro, this is a pretty interesting thread but i think that u just got in the wrong time, /sci/ seems to be very slow at night (comparint it to the other boards)

>>	Anonymous Mon Jun 14 04:23:57 2010 No.1181327 >>1181320 True. I've saved my posts so I can do this later. Still mad though.

Anonymous Mon Jun 14 04:31:57 2010 No.1181360

>>1181171
Unfortunately I have nothing to contribute for you sir but this is a great idea and i applaud your efforts. The more knowledge we spread on /sci/ and throughout society the better and more educated our world can become. If you have any more info on any subject please continue :)

>>	Anonymous Mon Jun 14 04:33:57 2010 No.1181365 bump

>>	Anonymous Mon Jun 14 04:33:57 2010 No.1181368 Wish I could contribute. I study math and everything worth explaining just comes out like word salad because there's no way to reduce it to anything people usually know.

Anonymous Mon Jun 14 04:46:57 2010 No.1181407

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 Mon Jun 14 04:47:57 2010 No.1181412 >>1181407 By the way, sorry about ruining every medical show ever with that.

>>	Anonymous Mon Jun 14 04:51:57 2010 No.1181431 Bump

>>	Anonymous Mon Jun 14 04:54:57 2010 No.1181436 If you are reading this thread, please respond. I want to know who's reading this.

>>	Anonymous Mon Jun 14 04:59:57 2010 No.1181444 please op, more information like this, i appreciate it

>>	Anonymous Mon Jun 14 05:01:57 2010 No.1181450 you guys are tards, god made your heart perfect only sinners get heart attacks

>>	Anonymous Mon Jun 14 05:02:57 2010 No.1181454 >>1181444 I'm spent right now. I typed all that up by myself. Do you have anything to contribute? It can be any subject.

>>	Anonymous Mon Jun 14 05:03:57 2010 No.1181455 Are fat levels all that affect the chances of getting a heart attack? And, are externally visible levels of fat (more or less) directly proportional to inside-of-veins-fat?

Anonymous Mon Jun 14 05:08:57 2010 No.1181470

>>1181455
There are probably other factors. I can think of exercise levels. If you don't exercise and then do something strenuous, there's a higher chance of a heart attack than if you normally exercise. There's also probably some other things I don't know.

As for that, well, I honestly don't know, though I'd have to imagine that more visible fat probably means a better chance of a heart attack. As far as I know, where fat deposits is random, so it could deposit in the legs or something (that's not good either, though).

I'm only speaking from an anatomy and physiology course, not full-blown medical school stuff. I only know this because we talked about diseases and shit. I'm not too sure on the stuff in this post, but it makes the most sense to me.

>>	Anonymous Mon Jun 14 05:10:57 2010 No.1181477 >>1181436 I'm reading

>>	Anonymous Mon Jun 14 05:12:57 2010 No.1181481 >>1181436 pretty awesome topic so far

>>	Anonymous Mon Jun 14 05:13:57 2010 No.1181482 >>1181436 I'm reading this!!

>>	Anonymous Mon Jun 14 05:14:57 2010 No.1181487 >>1181436 Please, continue. I am reading and waiting for more.

>>	Anonymous Mon Jun 14 05:17:57 2010 No.1181501 >>1181477 >>1181481 >>1181482 >>1181487 Well, unfortunately, I don't really have anything else to say on heart attacks. Maybe you'd be interested in something else anatomy related? Maybe stuff on the kidneys and how they work?

>>	Anonymous Mon Jun 14 05:22:57 2010 No.1181521 >>1181501 Kidneys are OK too.

>>	Anonymous Mon Jun 14 05:32:57 2010 No.1181555 Fuck, I'm sorry, it's getting late. I didn't realize. I'll remake this thread later with this info and add more then.

Anonymous Mon Jun 14 05:33:57 2010 No.1181557

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 Mon Jun 14 05:37:57 2010 No.1181568

funny thing is a large number of heart attack patients don't display any conventional symptoms of a heart attack.... e.g obesity causing arteries to be clogged up.

they are now researching other links to heart attacks, one that came up were disieses increasing your chance of a heart attack.

eg people with gum diseases are more likely to die of a heart attack

cant remember actual figures but i have the science magazines at home that discuss it

Anonymous Mon Jun 14 05:46:57 2010 No.1181589

OP what about explaining how cadiac muscle fiber differs from skeletal muscle fibers or smooth muscle fibers, and what happens depending on where in your heart the clot lodges itself

>>1181172
also fat is not bad for you, and as far as I'm concerned, the clogged arteries is called ateriosclerosis, the angina pectoris is a sort of heart cramp that can come of this

Either way the current theory is that it's your VLDL cholesterol that is the culprint of clogged arteries, which sort of makes sense looking at the current and past statistics. How does it make sense? Well.
One of the ways for our bodies to make VLDL is with fructose, you see it doesn't have to ability to be broken down by our normal cells, it has to be processed by the liver and here it has a couple of things to do, to mention a few it can either be use to replenish liver glycogen, be used as pure energy OR be converted to fat. This fat is the packed neatly into a VLDL protein and sent off

>>	Anonymous Mon Jun 14 05:48:57 2010 No.1181597 >>1181557 I think I remember this one, wasn't she the 18-19 year old student?

>>	Anonymous Mon Jun 14 05:51:57 2010 No.1181602 >>1181597 yup.

HHnnngghhh Mon Jun 14 06:05:57 2010 No.1181622

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 Mon Jun 14 06:05:57 2010 No.1181626 i support this thread i would contribute but i have no extensive knowledge on any one particular subject

HHnnngghhh Mon Jun 14 06:05:57 2010 No.1181627

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 Mon Jun 14 06:33:57 2010 No.1181687

>>1181622
>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.
Oh economists. Thinking you can argue about "primitive" cultures without keeping up with anthropology.

I mean, first of all, there are still many hunter-gatherer/tribal/whatever societies. Of course the majority of humans don't live that way, but to say that no one does anymore is silly.

I'm not going to say that people within these groups only produce one thing, but the view that knowledge isn't asymmetric in these societies, or that there isn't specialization to varying degrees among them, is just wrong.

Finally, in a more general criticism, you seem to waffle between information being a thing with value, and information as a thing without value that lets you produce things with value.

HHnnngghhh Mon Jun 14 06:44:57 2010 No.1181701

>>1181687

I'm not denying the existence of some specialisation in primitive communities, but it sure as hell is a lot more simple than in developed economies. In other words, their specialisation is pretty much negligible. I base my words not on original research, but on what I have read in North's (and others') papers.

On one hand information is valuable, because it lets you make proper decisions, but information asymmetry leads to the emergence of large transaction costs - costs that would not occur when information is symmetric and/or perfect. These costs are always incurred, but they don't necessarily add any value to produced goods.

>>	Anonymous Mon Jun 14 06:49:57 2010 No.1181711 Thanks Op, I feel educated.

>>	Anonymous Mon Jun 14 07:04:57 2010 No.1181742 >>1181602 Yeah i remember now, it led to the rules being enforced so dcotors won't work 48 hour shifts anymore

>>	Anonymous Mon Jun 14 07:08:57 2010 No.1181753 hurrdurr I hate not being able to choose a topic. However thanks, because this shit about the heart will come in useful later during exams.

>>	Anonymous Mon Jun 14 07:17:57 2010 No.1181777 >>1181701 I'm guessing those anthropology 101 classes don't actually teach any solutions to those problems...

>>	Anonymous Mon Jun 14 07:20:57 2010 No.1181795 >>1181777 No. Obviously he is implying that the solution is to create another Google.

/sci//m//e//d//f//a//g/ (also /tg//jp/) Mon Jun 14 07:26:57 2010 No.1181808

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 Mon Jun 14 07:50:57 2010 No.1181857
File: 120 KB, 1323x275, v-fib.jpg [View same] [iqdb] [saucenao] [google]

>>1181407
Nice topic, but this is a little bit off.

A heart attack just refers to hypoperfusion of heart tissue- inadequate blood flow. It does not necessarily mean the heart stops. With modern cardiac protocols it is quite possible to recognize and treat a heart attack before imminently fatal dysrhythmias develop.

The SA node is the primary pacemaker of the heart, but there are numerous backup pacemakers. All of these can produce a survivable rhythm in the right circumstances, so defibrillation is not necessarily indicated just because the SA node is not in control. Defibrillation is used to reset the conduction system of the heart during certain specific dysrhythmias which result either from the simultaneous discharge of multiple pacemakers or from a single pacemaker that is beating too quickly.

Also, the heart's "voltage" is not very strong. It is quite weak actually, but it doesn't take a whole lot of electricity to coordinate muscle contraction.

Pic shows ventricular fibrillation, an imminently fatal dysrhythmia caused by multiple uncoordinated pacemakers firing simultaneously, converted to a sinus rhythm (SA node in control) by defibrillation.

>>	Anonymous Mon Jun 14 07:59:57 2010 No.1181881 I like this thread idea, learning things I wouldn't have otherwise bothered to look up.

>>	Anonymous Mon Jun 14 08:12:57 2010 No.1181917 Fascinating.

Anonymous Mon Jun 14 08:13:57 2010 No.1181922
File: 46 KB, 900x431, 2adeno_2a.jpg [View same] [iqdb] [saucenao] [google]

>>1181857
Something that most people may not be aware of is that the same thing can be achieved using drugs instead of electricity. The drug adenosine can also be used to temporarily stop the heart in order to give the SA node a chance to start operating normally. It's not as reliable as electricity so it's not generally used for the most serious dysrhythmias like v-fib, but is a lot easier on the patient and less likely to cause damage to the heart muscle. It's often used with various types of tachycardia (abnormally fast heart rates).

The pic shows SVT converted with adenosine into a sinus rhythm. SVT (supraventricular tachycardia) is a rapid heart rate originating from a pacemaker above the ventricles. In this case, the far left shows a heart rate of about 170 beats per minute (normal is 60-80), then the pause in the middle is caused by the drug. It converts to a sinus rhythm at about 85 bpm.

Anonymous Mon Jun 14 08:14:57 2010 No.1181924

Good morning /sci/! I will add my molecular biology-related 'did you know' here:

I'm sure that most of us on /sci/ know that inside the nucleus of our cells is our genome - the DNA that makes me me and you you. This would theoretically allow us to clone ourselves from nearly every cell in the body, if we had advanced enough technology. Did you ever wonder, however, why our cells are different? A skin cell and a liver cell from Bob over there both have the same DNA in their nucleus, but the cells are vastly different in what they do. So, what controls this difference? It can't be on the level of DNA since the DNA is the same.

Enter a neat little thing called 'expression'. In simple English, this means whether a gene is being transcribed and translated (being made into mRNA and proteins) by your cells. To go back to the liver/skin cell example, the liver cell would be expressing 'liver cell' genes and the skin cell would be expressing 'skin cell' genes. Gene expression control is done at many levels but controlling transcription is one of the most common ways of controlling gene expression.

>>	Anonymous Mon Jun 14 10:17:57 2010 No.1182294 Bumping an awesome thread

Anonymous Mon Jun 14 10:24:57 2010 No.1182324

Eye shine, commonly seen within cats and dogs, is thanks to a layer of a tissue called a Tapetum Lucidum. It is a reflective layer of tissue that sits behind the retina and is able to bounce light back to it, effectively giving the light a second chance to be perceived. This greatly enhances the ability to see in low light conditions, but is believed to affect the acuity of the image, due to light reflected off the Tapetum Lucidum interfering with direct light.

>>	Anonymous Mon Jun 14 10:32:57 2010 No.1182346 >>1181172 >>1181171 >Mindless parroting of Another Heart Attack propaganda Learn what calcification does to your arteries and learn why cholesterol is vital for preventing heart attacks. Pieces of shit like you make me sick. Fuck you.

>>	Anonymous Mon Jun 14 10:46:57 2010 No.1182388 >>1181172 Fat isn't bad for me, it saves me having to carry around 6 times as may carbs.

Anonymous Mon Jun 14 10:46:57 2010 No.1182391

The vomiting reflex is controlled by a small portion of your brain at the base of your fourth ventricle. It is one of the only portions of the brain that is not covered by the blood-brain barrier. This allows harmful chemicals that may be present in the bloodstream to elicit a vomiting response to reduce further absorption.

>>	Anonymous Mon Jun 14 10:48:57 2010 No.1182403 2+2=7

Anonymous Mon Jun 14 10:55:57 2010 No.1182427

What's up bitches, I'll be talking about computers or something.

You've all probably seen the 1101001101100111 and shit in stuff related to computers (movies usually). Those digits are called binary digits, simply because they can have two different states ("bi" is Latin and means two), 1 and 0. And if you've ever taken any mathematics classes you'd know that bits (which comes from "binary digits") are numbers in base 2, decimals are numbers in base 10 (10 different digits), octals are numbers in base 8, hexadecimals are numbers in base 16 etc. You can write a number in any base you want actually, it doesn't matter. For example, 42 is 101010 in binary, which is 2A in hexadecimal, etc.

Well, the computer handles the data in binary, simply because it's much fucking easier for him. He only has to handle two different states (1 and 0). Imagine if the computer had to work in base 16 (hexadecimal), he'd have to handle 16 different states. Anyway, so as I said binary is the easiest. That way, when the data goes along the cable, a 5V impulse could mean 1 and a 3V impulse could mean 0. The computer on the other side can the interpret the impulses and reconstruct the data. And that's how fucking data travels.

Actually there's too much stuff to talk about, tell a Computer Science graduate what computer-related subject to talk about.

Anonymous Mon Jun 14 10:56:57 2010 No.1182429

>>1181407
Not OP here.
>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.
This is why an AED will analyze the situation for you, and either give a shock, or tell you to start chest compressions. (I'm out-of-date on my CPR training, but I still remember that from my last session)

>>	Anonymous Mon Jun 14 10:58:57 2010 No.1182436 >>1181407 more on the heart, circulatory system, and medical science in general. Thank you OP. =]

>>	Anonymous Mon Jun 14 11:02:57 2010 No.1182451 >>1182427 How do actual calculations happen within a computer? I mean HOW does it add? i know there are diodes electricity flow, but how does the computer physically resolve addition?

>>	Anonymous Mon Jun 14 11:03:57 2010 No.1182455 File: 39 KB, 604x453, 1272943385080.jpg [View same] [iqdb] [saucenao] [google] well, i never studied huan health or anything but i knew all of that already. except for the reason the pains come from the shoulder

Anonymous Mon Jun 14 11:05:57 2010 No.1182465
File: 15 KB, 300x286, 3338_0_fatwomansittingonman.jpg [View same] [iqdb] [saucenao] [google]

>>1181172

>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.

Someone correct me if I am wrong but in this situation the heart will be stimulated to grow NEW blood vessels to supplement the ones that are being constricted?

Anonymous Mon Jun 14 11:06:57 2010 No.1182474

>>1182427
I'll go off from your topic and talk about Ethernet (I'm also a CS graduate, and I've now been working in the industry for a couple years).

In the field of networking, there's an abstraction model called the OSI Seven-Layer model. Most of you probably think of "networking" as mainly dealing with Layer 3 (IP), and sometimes with Layer 4 (TCP/UDP). I'm here to talk about Layer 2 though.

The first Ethernet standards transmitted over a shared coaxial cable. Computers would have a piece of hardware that had a vampire tap that dug into the cable to make contact. Because the cable was shared among all machines, only one machine could transmit at a time, and all other machines on the cable would "hear" the signal.

>>	The ThunderBird !!ywzdHL9EJZq Mon Jun 14 11:12:57 2010 No.1182510 >>1182474 Do you throw away your pepperoni pizza? :)

Anonymous Mon Jun 14 11:16:57 2010 No.1182525

>>1182451
By using logic gates (AND, OR, XOR, etc.), if you've been on those powder game threads, you should've seen people building logic gates and should know how they work and what they are. It's just fuckin' around with logic gates basically. Once you get to increment an integer with logic gates, you can pretty much do any other operation.

>>	The ThunderBird !!ywzdHL9EJZq Mon Jun 14 11:16:57 2010 No.1182530 >>1182510 Correction: Sausage pizza

Anonymous Mon Jun 14 11:18:57 2010 No.1182538

>>1182474
In 1990 the standard for 10BASE-T was ratified. This was the first Ethernet technology to operate over "twisted pair" cable. You probably know this as "Cat5" cable, but at the time Ethernet could run over "Cat3" cable, which only had to be good enough for the phone standard (POTS, or Plain Old Telephone System -- I love that acronym :) ).

10BASE-T runs at 10 megabits per second (Mbps). Unlike the earlier coaxial system, this technology runs point-to-point, rather than having a cable shared by all systems. That meant that a break in the cable would only sever the connection between two nodes (since the coax cable had to be properly terminated in order to work, any break would cause all nodes to lose connection with all other nodes). However, only one device on each "network segment" could transmit at a time, because all machines on a segment were connected with repeaters that simply took in the signal from one port, and copied it to all ports (including the port that transmitted it). If two devices "talked" at the same time, then the signals overlapped. In the Ethernet standard, when these "collisions" occur, all devices must send out a special signal that signifies that a collision occurred, so the transmitting devices know that their data was not properly received (usually, so they know they have to retransmit).

>>	Anonymous Mon Jun 14 11:20:57 2010 No.1182548 >>1182525 thanks muchly!

Anonymous Mon Jun 14 11:33:57 2010 No.1182612

>>1182538
In 1995, the "Fast Ethernet" standard was ratified, taking twisted pair cable up to 100Mbps. It also introduced the standard for Autonegotiation, though it wasn't required for ethernet devices at the time. ANeg works by sending signals that are backwards compatible with the synchronization signals sent by 10BASE-T devices every few milliseconds when they're trying to establish a link (the voltage graph looks very similar to an EKG graph of your heartbeat, interestingly enough) For ANeg devices though, this signal is encoded with a small bitstream that tells the device on the other end what technologies you support. One analogy I heard goes like this: if you're stuck on an island, and you start seeing bottles wash up on shore with messages you can't read, you might send back a message listing all of the languages you speak. The other guy understands what you're doing, so he sends back a list of all the languages he understands. You circle one, and then you start actually communicating.

Anonymous Mon Jun 14 11:44:57 2010 No.1182667

>>1182612
Two years later, the standard for Full Duplex was ratified. Unlike the "Half Duplex" communication that was used before, where only one device on a network segment could transmit at a time, Full Duplex allowed all devices to transmit simultaneously. Full duplex is only possible if you have strict point-to-point communication though, so you had to have switches instead of repeaters.

Autonegotiation still wasn't required, so you could hook up a 100BASE-TX (Fast Ethernet) device to another 100BASE-TX device, where one has ANeg and one doesn't. The non-ANeg device would send out the Fast Ethernet "idle" signal, the ANeg device would see it, and figure out what to do. It would assume a 100Mb, Half Duplex link.

This led to a problem though. If you hooked up a non-Aneg Full Duplex device to an ANeg device, the ANeg device would see a 100Mb signal, and assume Half Duplex, since it couldn't tell otherwise. The Full Duplex device could continuously transmit data, and would (rightfully) ignore any collision notifications it received from the ANeg device. ("What do you mean we're colliding? There are no collisions in Full Duplex.")

Anonymous Mon Jun 14 12:05:57 2010 No.1182768

>>1182667
Then in 1999, the Gigabit Ethernet standard (1000BASE-T) was ratified. Autonegotiation was finally required, so the link would always either succeed or fail, so you'd never have a situation where a link was set up, but not working. Also, although Half Duplex was in the standard still, hardly anyone implemented it, because nobody took it seriously. This meant that if you hooked up two Gigabit Ethernet devices to each other, it would almost always "just work". Cat5 cables work over short distances, but for the full 100m length allowed by the standard, you usually need Cat5e.

Also, due to the use of several technologies, the actual signal went no faster over the wire than with 100BASE-TX, at 125MHz (100BASE-TX used 4b/5b encoding, so the 125MHz signal is translated into a 100Mbps datastream). First off, they use PAM-5 encoding, so that multiple voltage levels are used to translate into multiple bits per clock signal. Next, all four pairs of wires are used to transmit and receive simultaneously. I think there may be something else to it as well, but I'm blanking on it at the moment.

Later, in 2006, the standard for 10GBASE-T was ratified. This allows 10 Gigabit speeds transmitted over twisted pair. This time, Cat6A cabling is required, though Cat6 is considered "good enough" for short runs. So far, there are no products on the consumer market that I know of that use 10GBASE-T, but it's starting to become available in the enterprise market.

>>	Anonymous Mon Jun 14 12:08:57 2010 No.1182788 File: 108 KB, 398x298, 1269273539190.jpg [View same] [iqdb] [saucenao] [google] >intelligent science thread

148 !!sb15DRkDNtM Mon Jun 14 12:35:57 2010 No.1182929

Bump for more. I support this wholeheartedly. Here's some info about the science of lucid dreaming.

Lucid dreaming (term coined by Frederik van Eeden, 1913) is a state of cognition wherein the dreamer is explicitly aware that he or she is dreaming, while she is dreaming. During this, one is able to think and reason clearly, able to recall things from waking life and can act voluntarily, all while in a dreamworld that is often indistinguishable from the real world. (Greene, 1968; Kahan et al. 1997)
Looking at it from a brain perspective, it's an interesting conept. Lucid dreaming is physiologically defined as one part of the brain being in waking state, whilst the other is in dreaming state. (Hobson, Pace-Schott & Stickgold, 2000)

Scientific evidence for lucid dreaming was found by LaBerge et Al. in 1981. Previous studies had shown that REM eye movements during sleep correspond to the experiences in the dreamworld. (Fenwick et al. 1984; Roffwarg et al., 1962, to name some) LaBerge's subjects were asked to signal a specific pattern upon becoming lucid. The polysomnographs recorded showed these eye-movement patterns, proving that the subjects had been lucid. (Kahan & LaBerge, 1994; LaBerge 1990; LaBerge et al., 1981)

Anonymous Mon Jun 14 12:40:57 2010 No.1182961

>>1182768
One last thing I'll say about Ethernet, unless anyone has questions:
Some of you may know about "jumbo frames". The normal maximum frame size for Ethernet is 1518 bytes, if you include the 4-byte CRC. Originally, the limit was designed so that over Cat3 cable of questionable quality, you wouldn't have to retransmit shitloads of data if there was a bit error somewhere in a frame. Some devices allow higher limits, because this means you can reduce the processing overhead for sending data, especially when dealing with higher-quality cable that you see today. (while running data over your home LAN, you're unlikely to have bit errors, since most of your cables will be high-quality, and usually less than 5 meters)

The working group for the Ethernet standard (the IEEE 802.3 working group) even debated allowing "jumbo frames" into the standard, but they decided that backwards compatibility is king. If you can run all of your home devices at the same frame size though, it can reduce the overhead when transferring data around. Do some tests to make sure it's actually doing some good though, because if you have a device that's sending larger frames than the others can handle, you may be going slower than if you just left it alone.

>>	Anonymous Mon Jun 14 12:43:57 2010 No.1182977 >>1182961 Does the DHCP standard have an ability to tell clients what size frame to use?

>>	Anonymous Mon Jun 14 12:55:57 2010 No.1183055 i support this thread

>>	Anonymous Mon Jun 14 13:06:57 2010 No.1183135 Keep the science flowing.

>>	Anonymous Mon Jun 14 13:38:57 2010 No.1183308 bumpan for sciencey goodness.

Anonymous Mon Jun 14 13:38:57 2010 No.1183309

OP here. Glad to see the thread lived.

To the guys that corrected me/said I was correct: Thank you.

To the guy who said it was propaganda and talked about calcification: Would you care to explain, assuming you're reading this?

Anyway, I'll talk about blood flow a little bit.

If you're like me, you may have wondered, "Hey, what makes some blood flow here and not there?" Well, to be honest, it's simply the fact that there is a lot of blood to go around, so some of it will go up the arteries that branch off from the aorta due to the pressure from the heart (Note: There may be another reason. We didn't talk about this, so this is the most logical conclusion I come up with. Could someone either confirm this or explain what really happens?) For blood returning to the heart via veins, it's a bit more complicated. While blood from the head and upper areas can return via gravity. for blood from the legs and arms, that's not an option. Hence, veins (especially in the legs) have flaps in them. These flaps are shaped a bit like a "w". Blood from below pushes them open, and then they close when the blood begins to fall again. This allows the blood to work it's way up to the heart. With capillaries, blood flows through them until the cells supplied by them no longer need oxygen/have no more wastes that need removing. The cells send a signal to the opening of the capillary, which has a band of smooth muscle around it called the precapillary sphincter. It closes when the signal is received, preventing blood from going down there, thus forcing blood to go down another path.

That's all I can think of now. Again, someone please correct me if I'm wrong.

Also, contribute, people!

>>	Anonymous Mon Jun 14 13:43:57 2010 No.1183330 Bump

>>	Anonymous Mon Jun 14 13:51:57 2010 No.1183358 This is one of the best threads in a while.

>>	Anonymous Mon Jun 14 14:01:57 2010 No.1183423 Dammit /sci/, I mad again.

>>	Anonymous Mon Jun 14 14:04:57 2010 No.1183436 >>1183358 I guess I'll have to do something about that.

>>	Anonymous Mon Jun 14 14:07:57 2010 No.1183467 >>1183436 Like what?

>>	Anonymous Mon Jun 14 14:08:57 2010 No.1183482 >>1183467 One word. Magnets.

>>	Anonymous Mon Jun 14 14:10:57 2010 No.1183489 >>1183482 Is it true you can fuck up the inside of a computer with a strong magnet?

>>	Anonymous Mon Jun 14 14:13:57 2010 No.1183526 >>1183489 Yeah, you can destroy the hard drive.

>>	Anonymous Mon Jun 14 14:15:57 2010 No.1183544 >>1183526 How?

>>	Anonymous Mon Jun 14 14:18:57 2010 No.1183566 Bump for knowledge

Anonymous Mon Jun 14 14:35:57 2010 No.1183684

Encryption
Let's say Anna and Bob want to communicate, but don't want people picking up on their messages. Each computer has a public key which is availible to anyone who requests it, and a private key which is not. Anna writes "This is my message" and requests a copy of Bob's public key. She encrypts the message with Bob's public key, which turns it into a mess of seemingly random letters to anyone reading it. She then sends this to Bob, who can decrypt it with his private key. Since nobody else has Bob's private key, they can't decrypt it. Not very easily, anyway.
People can also digitally sign messages, which is sort of like a stamp which is unique to the sender, difficult to fake. To sign a document, the computer "hashes" it down to a few lines, which creates a "digest", then encrypts it with the private key. The created signature is appended onto the original message, which is then encryped with the reciever's public key and sent. The reciever then decrypts it with their private key, and separates the signature from the message. The reciever performs a hash on the message (using the same function as the original), and gets a digest. The reciever then requests a copy of the sender's public key and uses the public key to change the signature back into the digest. Then, the signature's digest is compared to the digest the reciever just created, verifying that the sender is who they are if they are the same. It proves the message has not been tampered with and it was sent by the correct person.

>>	Anonymous Mon Jun 14 14:40:57 2010 No.1183717 >>1183684 That was a little hard to follow... Nonetheless, do you have more to share? I find it very interesting.

>>	Anonymous Mon Jun 14 14:52:57 2010 No.1183763 Bump

>>	Anonymous Mon Jun 14 14:53:57 2010 No.1183770 >>1183544 Wiping it a couple of times over the HDD should suffice. If you know why that destroys all data, ask.

>>	Anonymous Mon Jun 14 14:54:57 2010 No.1183778 >>1183770 I presume you mean "If you don't know". Anyway, that's what I want to know.

>>	Anonymous Mon Jun 14 16:22:57 2010 No.1184486 Motherfucking bump

>>	Anonymous Mon Jun 14 16:29:57 2010 No.1184545 Bump for justice

Anonymous Mon Jun 14 16:36:57 2010 No.1184597

OP here. Gonna talk about the kidneys a bit. They're fucking complicated.

The outside is called the renal capsule. Inside of it, the kidney can divided into two sections: the renal cortex and the renal medulla. The renal cortex contains some parts of the nephrons (tiny, tiny structures in the kidney that filter the blood). The renal medulla contains the rest of it. Near where the renal artery enters and the renal vein and ureter leave (called the renal hilum) is a space inside the kidney called the renal pelvis. Wastes collect here before going down to the ureter and the bladder. Blood flow to the kidneys is rather odd. Blood goes through the renal artery, then the interlobar artery, then the arcuate artery, then the interlobular artery, then the afferent arteriole and into the glomerulus (part of the nephron). Blood leaves though the efferent arteriole. Reverse the order of the arteries and replace "artery" with "vein" for the path out. Wastes, when formed fromt the nephrons, goes down the renal pyramid (a structure, of which there are more than one, in the kidney) and into the minor calyces (singular: calyx), which empty into the major calyces, which empty in the renal pelvis, which becomes the ureter.

As for how the nephron works, well, that's rather complicated without diagrams. Plus, it's something I struggled with.

>>	Anonymous Mon Jun 14 16:45:57 2010 No.1184646 >>1181172 Hey OP, I just started reading. Can you do one for an brain aneurysm. I know it's sort of the same thing but I'd like to hear it.

Anonymous Mon Jun 14 16:47:57 2010 No.1184656

>>1183778
Yeah, meant if you didn't know, mistake there.
Anyway the HDD stores data in these sort of compasses that are located on numerous layers. There are millions and millions of these compasses inside a hard disk, one compass for each bit. One side of the arrow represents a 1 and the other 0. That way, the hard disk can just change the side of the arrow to change a certain bit. Of course, the arrows don't move around when you shut down your computer, otherwise all data would be lost or damaged. When you approach the hard disk with a magnet, it fucks up everything by changing the the positions of the arrows inside the compasses. That was a bit abstract but that's really how it works.

Anonymous Mon Jun 14 16:53:57 2010 No.1184700

>>1184646
I don't know anything about those. Other than "Shit gets clogged, shit dies as a result". I think it can also result in them bursting and bleeding to death, due to pressure buildup.

>>1184656
They aren't literal compasses right? And one for each bit? Wow.

Anonymous Mon Jun 14 17:17:57 2010 No.1184931

Let's talk about muscles.

Muscle is a broad term for three types of tissue: Skeletal (no points for guessing where this is), smooth, and cardiac (same). The different tissues are similar in some ways and different in others. Off the top of my head, skeletal muscle is striated (I'll get to that later), not branched, and under voluntary control. Smooth muscle is not striated (that's why it's "smooth"), not branched, and under involuntary control. Cardiac muscle is striated, branched (cells split into two parts sometimes and meet with other branches, forming things called intercalated disks between them), and under involuntary control. I do know there are other things I could say about them, but I forget what.

Anonymous Mon Jun 14 17:17:57 2010 No.1184938

Continuing.

Anyway, skeletal muscle is what most people think of when someone says muscle, and is attached to the skeleton via tendons and to each other via ligaments. Skeletal muscles typically work in pairs. Muscles can only pull via contraction, not push. For every flexing muscle, there needs to be an extending muscle to help straighten it out again (for the record, flex=reduce the angle between two parts of the body, extend=increase the angle). They are antagonists, and when one contracts the other relaxes. The best example is the biceps brachii (it's technical name, "two-headed muscle of the arm") goes from (has it's origins at) the shoulder blade (the scapula) at two different parts to the radius (a bone in the forearm, always on the side of the thumb (it rotates in the arm as you flip between the back of the hand and the palm)), where it has it's insertion. Muscles always contract, pulling the insertion to the origin (in this case, the radius (and thus the forearm) to the upper arm). The triceps brachii ("three-headed muscle of the arm") comes from the scapula and two places on the humerus (upper arm bone) and down to the ulna (other bone in the forearm, stays on pinky side and doesn't rotate). When the triceps contacts, it pulls on part of the ulna in a way that it straightens out (I can't think of how to explain it). All muscles work like this, sometimes in pairs, sometimes not. Almost all muscles used for flexing are found on the front of the body, and almost all the muscles used in extension are on the back. The exception are the thighs, with the quadriceps femoris ("four-headed muscle of the femur"), which are in the front and extended the knee, and the hamstrings, which flex and are in the back.

I'll get to what striated means later.

>>	Anonymous Mon Jun 14 17:18:57 2010 No.1184947 >>1182465 It's a bit late, but yes, the heart will make new blood vessels there. Forgot to mention that. In angina pectoris, the heart will recover due to the new vessels. In a heart attack, the cells are dead and new vessels won't help.

Anonymous Mon Jun 14 17:26:57 2010 No.1185016

Now, smooth muscle and cardiac muscle work in slightly different ways. Smooth muscle is found primarily in the digestive tract, pushing food through involuntarily. Smooth muscle contracts slightly differently, since they're organized differently (when I get to what striated means, it'll make more sense). Cardiac muscle is found, no surprise, in the heart. It contracts just like skeletal muscle, except it's under the control of the SA node, or whatever is acting as the pacemaker.

How do the muscles contract? It does this through two tiny filaments in the cells, actin and myosin. In skeletal and cardiac muscle, these are arranged in such a way that lines are formed on the muscle, making it look striated. Smooth muscle is not organized in this way. The way skeletal and cardiac muscle are organized is with a sarcomere. The sarcomere is the part of the muscle that contracts. It consists of alternating horizontal bands of actin and myosin.

I'll get to how it contracts a bit later, I'm getting exhausted right now.

>>	Anonymous Mon Jun 14 17:27:57 2010 No.1185030 Also, after this 404's, I'll make the new thread with the same picture (I'll copypasta all of my posts, so don't worry about reading it all right now).

>>	Anonymous Mon Jun 14 17:29:57 2010 No.1185047 Also, post please if you are reading this. Just curious to see who's reading.

>>	Anonymous Mon Jun 14 17:51:57 2010 No.1185199 reading it, loving it.

>>	Anonymous Mon Jun 14 17:53:57 2010 No.1185215 Ive been checking since 10 am =)

>>	Anonymous Mon Jun 14 18:21:57 2010 No.1185424 File: 9 KB, 374x251, Sarcomere[1].gif [View same] [iqdb] [saucenao] [google] Guys, I just can't do it. It's been so long since I learned this shit, and looking over stuff is not helping me. I fried my brain earlier. Maybe a medfag could help out?

Anonymous Mon Jun 14 18:22:57 2010 No.1185428

Heya, reading. Was the person who posted the little bit on molecular biology, but it seems that very few people if any took interest in it. Maybe I should switch to things interesting to a more general population.

Hmmm....oh, I know:

A common misconception is that being HIV+ and having AIDS are the same thing. Not quite.

HIV is the Human Immunodeficiency Virus. AIDS is Acquired ImmunoDeficiency Syndrome (letters caps'd for emphasis). When you are HIV positive, it means you have little HIV viruses floating around inside your blood. You can still function just fine for a few years even though you are infected with the virus, however. In fact, there are some carriers out there that are HIV + that never get AIDS.

AIDS is a result of the virus doing its nasty work in you. HIV is a sneaky bastard - it takes out the 'generals' of your immune system, to use an army analogy here. These generals are your T helper cells. T helper cells encourage your body to fight infection by telling your B cells to go ahead and make antibodies. So what do you think happens when there are little to no T cells around to tell your B cells to make antibodies? That means your body's a sitting duck to any bacteria or virus out there that thinks 'ooh what a nice place to live and multiply in'. This is why AIDS patients need to be kept in very clean environments.

Keep in mind, however, that HIV can take its sweet ass time killing T helper cells (your immune system also actively fights HIV, but it's a slow losing battle) before your body ends up in a bad way. This is why it takes time before someone who is HIV+ will develop AIDS.

Anonymous Mon Jun 14 18:22:57 2010 No.1185430

>>1181922

Interesting. I know you posted this 10 hours ago but maybe someone else knows the answer to this. The adenosine would need to be done intravenously I assume to get such a rapid effect, but does it just get metabolized very quickly and loses effect after only several seconds? Or is there something inherent to the mechanism of the drug that it only stops the heart for a short period of time and then the heart starts again without the adenosine concentration having to drop again? Hopefully that makes sense, it seems strange to me that a drug can have such a large effect for such a short period of time.

>>	Anonymous Mon Jun 14 18:23:57 2010 No.1185435 >>1185424 Oh, ignore the picture. Or don't. I meant to use it in my description, and forgot to remove it.

>>	Anonymous Mon Jun 14 18:24:57 2010 No.1185438 "-I HAVE A DEGREE IN HOMEOPATHIC MEDICINE! -You have a degree in baloney!"

Anonymous Mon Jun 14 18:28:57 2010 No.1185458

>>1185424

The sarcomere is composed of 2 kinds of filaments: actin and myosin. In the picture, myosin is the thick filaments and actin is the thin filaments. Muscle fibers contain loaaaaads of sarcomeres in a row (so take the image, duplicate it and place them side by side x 100).

During contraction, the actin and myosin filaments slide around to create a more compact structure. Again, using the picture as reference:

|--------- ----------|--------
| ========= | =======
|--------- ----------|--------
^ uncontracted

|--------- --------|-------
| ========== | =====
|-------- ---------|-------
^ contracted

Now think about a whole chain of sarcomeres contracting like my badly drawn diagram above! The muscle fiber gets drastically shorter as a result. Keep in mind that this process requires energy and a signal for contraction to occur.

>>	Anonymous Mon Jun 14 18:29:57 2010 No.1185465 >>1185458 Shit, I fail at drawing diagrams in 4chan. The 'uncontracted' image - please replace it with the picture here: http://images.4chan.org/sci/src/1276554082103.gif

>>	Anonymous Mon Jun 14 18:33:57 2010 No.1185497 >>1185465 It's cool. At least someone is trying. OP here. Maybe there's some other aspect of anatomy I could answer?

>>	Anonymous Mon Jun 14 18:40:57 2010 No.1185540 Neurofag here. Feel free to ask questions

>>	Anonymous Mon Jun 14 18:44:57 2010 No.1185565 >>1185540 OP here. Unfortunately, I don't have any questions. How about you just type something up on a topic of your choosing for us? That's the point of this thread, to show off your knowledge and educate others in the process.

>>	Anonymous Mon Jun 14 18:45:57 2010 No.1185573 Any more on molecular biology, maybe some chemistry even? Thanks for the effort.

>>	Anonymous Mon Jun 14 18:46:57 2010 No.1185584 >>1185573 OP here. I fucking love organic chemistry. I've been learning freelance though, and I'm not done learning everything. Do you have a question in mind, or should I just start rattling off random crap?

>>	Anonymous Mon Jun 14 18:48:57 2010 No.1185606 >>1185584 Great! Any topic of your choosing =)

Anonymous Mon Jun 14 18:48:57 2010 No.1185610

>>1181407

Actually a defibrillator can be used on a flatline if it is suspected that it really is a high frequency fibrillation masking as a flatline.

But it isnt a heart starter - go CPR.
check out http://www.supersexycpr.com/ if you dont already know how to do it

>>	Anonymous Mon Jun 14 18:50:57 2010 No.1185631 >>1185584 Can you explain why hydroxy/amine groups can feed electrons into aromatic rings so easily? I understand the underlying stuff (lone pairs, electron orbitals lining up) but in a way that makes it entirely clear?

>>	Anonymous Mon Jun 14 18:53:57 2010 No.1185654 ask a geologist / minerologist anyfing

>>	Anonymous Mon Jun 14 18:54:57 2010 No.1185663 I have a question what causes people to forget some thing one day but remember it later? Like some one asks me the name of a song that is playing but i cant remember but 2 days later out of the blue bam i now remember.

Anonymous Mon Jun 14 18:57:57 2010 No.1185686

>>1185663
at its root, associative memory.
There's a saying "Neurons that fire together wire together", basically, an example would be conditioning (e.g. Pavlov). I shock myself every time I eat cheese, I eat cheese and my body "expects" to feel a shock. Same with the song. You unconciously 'remember' it, but it needs to be brought into focus by a stimulus.

Anonymous Mon Jun 14 18:58:57 2010 No.1185687

>>1185663
Thats like asking why you can't instantly recall all information accurately at any given moment. Your memory works in clusters or blocks of information. Ie, if someone tells you Sun, you will think Hot, Bright, Hydrogen, Earth, Solar System ... etc.

Anonymous Mon Jun 14 19:00:57 2010 No.1185709
File: 15 KB, 250x170, Chirality_with_hands[1].jpg [View same] [iqdb] [saucenao] [google]

>>1185610

I did not know that. Neat.

>>1185606
I'll talk about chiral compounds, then. I know it took me a while to understand.

The picture is a generic representation of an amino acid, with each "hand" representing a stereoisomer of the amino acid (Fun fact: Chirality roughly means handedness). The left hand, while being identical in terms of what's bonded to what to the right hand, can't match up exactly with it. You may think, "Well, rotate it 180 degrees!" However, the carbonyl (COOH) group would be on the bottom, with the amino group (NH2) on top. You may then say, "Well, rotate it on it's long axis!" However, while everything would line up, where the right hand is pointing up, the left hand would be pointing down, and vice versa. No matter how you try, the left hand can't look exactly like the right hand. If you do make it look like the right hand, then it's not chiral. It is achiral.

Chirality is important, because many medicines and natural chemicals react differently depending on how the molecule is arranged in space. For example, Thalidomide was a drug used in the 50s for morning sickness for pregnant women. It had two enantiomers (ways of being arranged in space), which are called R and S enantiomers (how the naming works is something I don't get). The R enantiomer works wonders against morning sickness. However, the S enantiomer fucks up unborn babies. And since it's meant to be taken when you're pregnant...yeah. Thalidomide was sold as a mix of both enantiomers (they didn't know that at the time). However, it turns out that the R enantiomer becomes the S enantiomer in the body. So there's no way around it.

See how chirality is important?

Anonymous Mon Jun 14 19:03:57 2010 No.1185739
File: 8 KB, 225x300, 20060321_thalidomidebaby_3[1].jpg [View same] [iqdb] [saucenao] [google]

>>1185631
Like I said, I don't know everything yet. Sorry.

If I had to guess, I'd say that it has something to do with the orbitals of the aromatic rings being joined together, and when the hydroxy/amine groups bond, they get forced into that ring as well.

But remember, I'm kind of speaking out of my ass here.

Here, have a Thalidomide affected baby, as mentioned in my last post.

Anonymous Mon Jun 14 19:05:57 2010 No.1185753

>>1185654
Earlier, a religious nut on Yahoo (you might know what I'm talking about) said that the layers of rocks are all messed up, and that the aren't as pretty and organized as in the diagrams.

Was he just speaking out of his ass, or did he have a point? If he was right, what's the explanation of geology for that?

>>	Anonymous Mon Jun 14 19:07:57 2010 No.1185771 >>1185739 it looks perfectly happy, isn't that what matters? seriously though thalidomide was the same example my o chem professor used when he introduced chirality but you said it even better. fucking community college.

Anonymous Mon Jun 14 19:08:57 2010 No.1185782

>>1185573

Yes! Molecular biology, right up my street.

Proteins are crazy important in your body. I'm sure everyone hears the whole 'make sure you get essential amino acids in your diet' lecture every now and then, but did you ever wonder why?

See, protein is not just something you eat when you want to build muscle mass. Proteins do a whole load of functions in your cells, here are some examples:

Most enzymes (very few exceptions) are made out of proteins. An enzyme is a biological catalyst - in so many words, they make reactions happen at much faster rates (we're talking hundreds to thousand times faster) than if you stuck the reagents together in a bowl and left it to sit in air. An important example enzyme is DNA polymerase, which is involved in replicating your DNA during cell division.

Some proteins are signals that tell your cells to do something. For instance, insulin is a protein, and I don't think I need to tell you how important that is.

PART 1 OF 2

Anonymous Mon Jun 14 19:10:57 2010 No.1185797

>>1185782

Other proteins are signal receptors - these act as the 'ears' and 'eyes' of your cells to detect signals from other cells. An example receptor is the insulin receptor. Please keep in mind that just because you have insulin, it doesn't mean that your cells will recieve the signal! You must have the receptor as well. Type 2 diabetes can occur when you have insulin, but no insulin receptor - cells do not 'see' the insulin and blood sugar levels do not fall after a meal.

Proteins are made up of amino acids. There are 20 amino acids that we use. Many proteins can be hundreds of amino acids long, so you mathfags out there can imagine the crazy kinds of combinations of amino acid sequences that exist in nature.

Our bodies can manufacture most of the amino acids required to function, but some must be acquired from our diet. If you don't get enough of the essential amino acids, your body cannot make certain proteins, which can lead to all sorts of crazy problems. Just imagine how much shit you'd be in without DNA polymerase, insulin or your insulin receptor.

PART 2 OF 2

Anonymous Mon Jun 14 19:11:57 2010 No.1185812

>>1185631

I can't see that there's anything particularly special to say about systems like that. Just draw the kekule structure, and no matter what you do you end up with the bonds arranged in a way that gives you something that looks like an enamine or an enol, both of which are pretty nucleophilic.

>>	Anonymous Mon Jun 14 19:12:57 2010 No.1185816 >>1185782 MOAR

>>	Anonymous Mon Jun 14 19:16:57 2010 No.1185845 Part 1/1 ; You can rig up a cow's heart to a car battery and have sex with it for ultimate pulsating vibro-climactic orgasm's.

>>	Anonymous Mon Jun 14 19:18:57 2010 No.1185858 >>1185845 ... wat

Anonymous Mon Jun 14 19:19:57 2010 No.1185867

>>1185816

Haha, sure, why not.

Since I'm on a protein kick....

In continuation with my last post, I said that amino acids were important for building proteins. Now, I'm sure some of you have said 'well....why can't we just substitute amino acid A for B and get around this deficiency?' Good question.

A lot of molecular biology works like magnetic lego/tetris (I shit you not). At the end of the day when you boil it down, it's all about shapes and charges.

Here's an example diagram:
http://www.mygaming.co.za/news/files.php?file=Tetris_172445586.png

In this tetris setup, we have a base (let's call it the enzyme) and a reverse L floating around (this is the substrate, what the enzyme will act on, use or modify). We can see clearly that the reverse L will fit into the square hole (or the sides) and not anywhere else. However, if the tetris pieces used to make the base (the amino acids) were different, the base would be different, and the reverse L would fit somewhere else!

Just to cover my ass, yes, I'm sure that there are a bunch of tetris setups that will give you that exact same base, but if it were a protein, I would highly doubt it would perform the same enzymatic function.

So now, we can see why amino acid sequence is important in protein structure. If y'all are interested, I will next move on to how mutations affect proteins.

>>	Anonymous Mon Jun 14 19:22:57 2010 No.1185891 >>1185867 Please, go ahead

Anonymous Mon Jun 14 19:28:57 2010 No.1185928

TETRAZOLES are often used in medicinal chemistry as a BIOISOSTERE for the CARBOXYLATE group. They accomplish this so well by virtue of their similar PLANAR SHAPE and PKA value.

(the more you know).

Will consider answering questions on organic chemistry.

Anonymous Mon Jun 14 19:28:57 2010 No.1185929

>>1185753

As most people know- alot of geology is built on sedimentology - the study of the deposits of sediments from rivers etc and how they form layers on the seabed.

What happens to these as they are buried deeper and deeper, is that processes called diagenesis and metamorphosis- basically change in structure due to pressure and heat eventually form solid rocks instead of just fine layers of particles.
But the structures and different chemical buildups of these are preserved to a certain degree and can tell us alot about the conditions in which the materials for these rocks were deposited.
What can happen once they are structural - is movement and displacement due to simple tectonics. They can be bent (called folding) or sheared and displaced with respects to itself - in what we call faults.
Sometimes major tectonic events can even invert them, and put a older body of rock on top of younger rock.

This is well understood, and it is in many cases possible to find the surfacestructures from the deposits to help us determine its "proper" orientation.

Anonymous Mon Jun 14 19:32:57 2010 No.1185964

A common misconception as to the reason for the immiscibility between oil and water is that the hydrophobic molecules repel the hydrophilic molecules.

This is not, however, the case, because the net Van der Waals attraction between a water molecule and a hydrocarbon is positive.

The key reason why oil and water don't mix is that, to solvate a hydrocarbon molecule, the water molecules must "freeze" around it in a cage-like structure, hydrogen bonding to each other and interacting with the hydrocarbon via VDW. This ordering of water molecules is entropically expensive, and so thermodynamics dictates that the system will prefer to be in a higher-entropy state, i.e. with no hydrocarbons solvated, i.e. the liquids will separate.

Anonymous Mon Jun 14 19:33:57 2010 No.1185980

>>1185929

What also happens is that these folded, fractured and inverted bodies are exposed again to the atmosphere and rain - and are weathered / eroded, before deposition once again begins on them. Meaning we find a column that is missing parts. We know that these areas were pretty vast in the past, and we can often use different localities to piece together a pretty acurate picture of what has happened as different processes can dominate at different times in different places.

But in no examples are they just plainly wrong- sometimes layers are missing, but we never find unexplainable strata that in anyway contradicts itself.
It usually means that a body of rock has a more complex history that plain sedimentation.

Anonymous Mon Jun 14 19:42:57 2010 No.1186040

>>1185891

Ok, so I last touched on how amino acid sequence is important for protein function.

What codes for amino acid sequence, however?

As we all know, DNA inside the nucleus of your cells codes for 'stuff'. This stuff is proteins. Your cells translate a code of ACTCTGCAT into an amino acid sequence by a process called translation (har har). For instance, the code ACT/CTG/CAT codes for the amino acid sequence threonine-leucine-histidine. Notice how I've divided the bases into blocks of 3. Each block of 3 (a codon) codes for an amino acid.

But wait! 4 possible bases in 3 positions gives a possible combination of 4^3 = 64 combinations. We only have 20 amino acids. No worries, it just means that multiple codons can code for the same amino acid.

Now, say we have a random X ray flying around that mutates this little DNA sequence:

ACT/CTG/CAT -> ATT/CTG/CAT

PART 1 OF 2

Anonymous Mon Jun 14 19:44:57 2010 No.1186048

>>1186040

This new sequence now codes for isoleucine-leucine-histidine instead of threonine-leucine-histidine. Oh noes! Now the protein that this sequence is part of is different!

How different? Well, that depends on a lot of things. For instance, was that threonine part of an important area of the enzyme, say, the part that interacted with the substrate? Ooh, maybe this enzyme now works on a totally different substrate. Or maybe, the threonine was placed in a location that didn't really do much at all. In this case, a mutation wouldn't affect too much.

Let's assume that the mutation altered enzyme function. For instance, the enzyme still can interact with its substrate (let's call it X) and convert it to a red pigment that shows up in fur. The mutated enzyme takes X and converts it instead to a black pigment. Voila! Your animal now is black instead of red.

PART 2 OF 2

>>	Anonymous Mon Jun 14 19:44:57 2010 No.1186055 >>1185929 >>1185980 Neat. However, let me play devil's advocate: How do you know that what you consider to be levels that moved around actually were moved and aren't the natural state?

>>	Anonymous Mon Jun 14 19:47:57 2010 No.1186078 >>1186040 So where does RNA come into all of this?

>>	Anonymous Mon Jun 14 19:49:57 2010 No.1186090 OP here. This thread has been saved by awesome people. Perhaps we could archive, for future knowledge? Half of it is me bitching, but the knowledge is nice. Also, anymore questions on organic chemistry? I might be able to answer them.

Anonymous Mon Jun 14 19:49:57 2010 No.1186094

>>1186055

>However, let me play devil's advocate: How do you >know that what you consider to be levels that moved >around actually were moved and aren't the natural >state?

Can you rephrase this? How we can tell how they have moved, or how we can tell that they have moved att all?
In relation to what?

>>	Anonymous Mon Jun 14 19:51:57 2010 No.1186104 >>1186090 How do I determine the resulting regiochemistry of the Diels-Alder reaction? It seems to have something to do with orbital coefficients?

Anonymous Mon Jun 14 19:51:57 2010 No.1186106

>>1186078

I skipped on RNA to avoid making things unecessarily complicated.

You ever go to the library and try to rent out this book that's on reserve that they won't let you take out of the library? What a pain eh. That book on reserve is the DNA in your nucleus. mRNA (messenger RNA) like you taking that book and copying the pages you're interested in reading so you can take it home to read. In cell terms, this means that the DNA sequence to make the protein is copied into an mRNA copy. The mRNA then goes into the cytoplasm to be translated into a protein.

Anonymous Mon Jun 14 19:52:57 2010 No.1186116

>>1186094
Yeah, it was a little confusing. Sorry.

Let's say that geologists believe that rocks are normally arranged like:

A
B
C
D

And then when they see the following:

A
C
B
D

They think that something caused B and C to switch around.

What I'm saying is, how do you know that C coming after B isn't the normal way? How are you sure that B should normally come after C?

>>	Anonymous Mon Jun 14 19:53:57 2010 No.1186128 >>1186104 ... Okay, I give up. I don't know enough about organic chemistry to really help most people. So, any anatomy questions?

>>	Anonymous Mon Jun 14 19:53:57 2010 No.1186130 So why can't we just translate directly from the nuclear DNA and cut out the middle man? Seems like it would be a ton more efficient.

>>	Anonymous Mon Jun 14 19:54:57 2010 No.1186139 >>1186128 Nooooooo, you can do it if you try! Believe in yourself, anon!

Anonymous Mon Jun 14 19:55:45 2010 No.1186146 [DELETED]

>>1181168
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Anonymous Mon Jun 14 19:58:57 2010 No.1186169

>>1186130

The cytoplasm is indeed a dangerous place. Reactions going off all the time, enzymes that chew stuff up floating around everywhere etc. The nucleus in comparison is a nice safe place where you can store your DNA without having to worry about it getting blown up. What if you accidentally your only DNA copy, eh? Having an mRNA intermediate allows your DNA to stay safe in the nucleus.

>>	Anonymous Mon Jun 14 19:59:57 2010 No.1186178 >>1186169 Forgot to add: Even if your mRNA copy gets blown up, who cares? You can just go make another :)

Anonymous Mon Jun 14 19:59:57 2010 No.1186180

>>1186116
Well there are several ways to attack the problem.
It is pretty intuitve that what is on top is younger than that further down, so dating is an option.

We can also compare the materials found to other localities. Some rock compositions are only formed under special conditions, so we can find certain periods by the minerals and rocks found, and fossils found in them.

Also it is usually possible to find at least some of the same
A
B
C
D

stratigraphy elsewhere.
And for
A
C
B
D
to exist it would have to be more like:

A
-discontinuity-
C
B
-discontinuity of some sort-
D

Rendering one of the columns as more prone to being rearranged than the first non-discontiunous one, if that makes any sense

>>	Anonymous Mon Jun 14 20:00:57 2010 No.1186182 I have a question: magnets; how DO they work?

>>	Anonymous Mon Jun 14 20:01:57 2010 No.1186186 >>1186180 I kind of follow you. So basically, there's dating, and the formation of special rocks, and it's obvious if something got fucked up, right?

>>	Anonymous Mon Jun 14 20:01:57 2010 No.1186187 >>1186182 Miracles.

>>	Anonymous Mon Jun 14 20:02:57 2010 No.1186196 >>1186139 No, really, I can't. >>1186169 Isn't the fact that RNA has uracil part of why things aren't translated directly from DNA? I'd think so, anyway.

>>	Anonymous Mon Jun 14 20:04:57 2010 No.1186204 >>1186196 RNA's got uracil because it's less costly to produce in the cell. Sure, it's unstable and can spontaneously degrade, but who cares, just make another RNA. Ribozymes, now there's an interesting use for RNA.

Anonymous Mon Jun 14 20:04:57 2010 No.1186205

>>1186186
More or less. Sometimes it is not completely obvious and the methods can be a bit more finicky than these simple cases, but thats the general idea.

However im sure there are some misplaced/misunderstood layers out there, but nothing like the creationists/religious guys make it out to be,

there are no precambrian bunnies in geology either.

>>	Anonymous Mon Jun 14 20:06:57 2010 No.1186214 >>1186182 electrically charged particles that spin / have motion creates a magnetic field.

>>	Anonymous Mon Jun 14 20:08:57 2010 No.1186233 >>1186204 What do you mean it costs less to make? And it's unstable?

>>	Anonymous Mon Jun 14 20:15:57 2010 No.1186281 Bump

>>	Anonymous Mon Jun 14 20:16:57 2010 No.1186287 >>1186214 http://en.wikipedia.org/wiki/Ferromagnetic

>>	Anonymous Mon Jun 14 20:20:57 2010 No.1186323 Oh sweet, this thread is still alive.

Anonymous Mon Jun 14 20:21:57 2010 No.1186326

>>1186233

It costs the cell less energy/chemical resources to synthesise it. It's "good enough", so the cell would rather use its precious energy elsewhere.

Uracil's just a bit more reactive than the other bases and more likely to be accidentally degraded, which makes it unsuitable for long-term information storage.

>>	Anonymous Mon Jun 14 20:22:57 2010 No.1186333 Bit of an organic chemistry question here I assume. Extraction of pure alcohol. How does it happen?

>>	Anonymous Mon Jun 14 20:24:57 2010 No.1186343 >>1186333 Distillation, I guess.

>>	Anonymous Mon Jun 14 20:26:57 2010 No.1186357 >>1186343 Fuckin proud of you.

Anonymous Mon Jun 14 20:28:57 2010 No.1186371

Thread is getting kinda lengthy but here are some great contributions. Just keep in mind though, if you what you are trying to get is the attention of others, don't use overtly-technical words or go doing "blank" references that the newcomer might not know. For instance, >>1182474, you have great inentions but I personally couldn't follow you. >>1185709 is another example, and while I could follow you exactly (BA chem here) I know it would be otherwise since I would have no idea what a "carboxyl" or "amine" is and thus, your message goes unnoticed as annoying "chem wording" with no immediate meaning.

So as you people, keep up the good job, but let's make it accessible and fun--this is not a cock waving contest nor a text-book rewrite thread. Not OP by the way, but I support his cause (fuck those annoying "geuss" threads).

>>	Anonymous Mon Jun 14 20:30:57 2010 No.1186378 >>1186371 OP and guy who made the chiral thing. Yeah, I probably should have considered it. I was too busy trying to show why they can't line up, and I took that knowledge for granted.

>>	Anonymous Mon Jun 14 20:33:57 2010 No.1186397 >>1181557 Serotonin Syndrome can also be caused by giving a patient Demerol when he/she is taking an MAO inhibitor (MAOI)

>>	Anonymous Mon Jun 14 20:39:57 2010 No.1186429 Everyone who made educational posts ITT is a good person and the cure for the cancer killing /sci/.

Anonymous Mon Jun 14 20:48:57 2010 No.1186494

>>1182977
>Does the DHCP standard have an ability to tell clients what size frame to use?
No, mainly because of the logical separation between the layers. The IP packet, for instance, doesn't care what protocol it encapsulates.

In theory you could build a proprietary protocol that can tell the drivers and firmware of the computers and switches on your network what frame size to use, but that would go against the standard. You'd also have to keep in mind that if you add a device to your network that doesn't support your new protocol, it will be difficult to get that device to work on your network.

>>	Anonymous Mon Jun 14 20:53:57 2010 No.1186533 Gimme a crash course in Quadratics. :D

>>	Anonymous Mon Jun 14 21:01:57 2010 No.1186588 >>1186533 ...Shouldn't school be out? Fine, what do you want to know?

Anonymous Mon Jun 14 21:06:57 2010 No.1186624

>>1186429

:-)
I am merely a high school student and will talk briefly of the respiratory system (off the top of my head because I gave in my anatomy textbook last week). I've been studying A&P for two years now. Anyway.

THE LUNGS
The lungs are two cone shaped organs located on thew upper back, by the shoulder blades. The right lung is bigger than the left lung and contains three lobes whereas the left only contains two. The alveoli (singular: alveolus) is the site of gas exchange, NOT the lungs! CO2 is exchanged for O2 during inspiration, O2 for CO2 in expiration. All that done for every breath! The lungs (and respiratory system) works as long as the heart works. Breathing eventually ceases after the heart stops beating. However, the heart does not stop being if you cease breathing. (You can be apneic and still have a pulse, but you can't be pulseless and still be breathing). A typical adult breathes anywhere from 12-20 times per minute. A number < 12 would be classified as bradypnea. A number > 20 would be classified as tachypnea. The brain stem controls the autonomy of the body (breathing, heart rate) and the diaphragm is the chief muscle that controls breathing. The diaphragm is controller by the phrenic nerve, located at C3-C5. If a break of the neck happens in this area, the phernic nerve cannot supply the diphragm with responses to contract, which causes the person to cease breathing.

PART ONE OF THREE

>>	Anonymous Mon Jun 14 21:19:57 2010 No.1186693 bump

>>	Anonymous Mon Jun 14 21:32:57 2010 No.1186797 bump for great justice

>>	Anonymous Mon Jun 14 21:36:57 2010 No.1186822 Bump. I want to learn about respiration.

>>	Anonymous Mon Jun 14 21:37:57 2010 No.1186825 I read the whole thread. OP, I am proud.

>>	Anonymous Mon Jun 14 21:39:57 2010 No.1186839 >>1186825 As am I. It's come so far since my bitching.

Anonymous Mon Jun 14 21:50:57 2010 No.1186914

>>1186624
Sorry for delaying, I am an EMT and went out on a call. Here is the continuation.

>>1186624
The lungs (and respiratory system) also acts as a buffer system! Not entirely, however. The kidneys play the most major role in controlling the pH (The H+ ions in conc (mol/L)).

The condition called respiratory acidosis occurs when blood pH falls as a result of decreased respiration. When respiration is restricted, the concentration of dissolved carbon dioxide in the blood increases, making the blood too acidic. Such a condition can be produced by asthma, pneumonia, emphysema, or inhaling smoke.

Metabolic acidosis is the decrease in blood pH that results when excessive amounts of acidic substances are released into the blood. This can happen through prolonged physical exertion, by diabetes, or restricted food intake. The normal body response to this condition is increases breathing to reduce the amount of dissolved carbon dioxide in the blood. This is why we breathe more heavily after climbing several flights of stairs.

Respiratory alkalosis results from excessive breathing that produces an increase in blood pH. Hyperventilation causes too much dissolved carbon dioxide to be removed from the blood, which decreases the carbonic acid concentration, which raises the blood pH. Often, the body of a hyperventilating person will react by fainting, which slows the breathing.

Metabolic alkalosis is an increase in blood pH resulting from the release of alkaline materials into the blood. This can result from the ingestion of alkaline materials, and through overuse of diuretics. Again, the body usually responds to this condition by slowing breathing, possibly through fainting.

PART TWO OF THREE

Anonymous Mon Jun 14 21:51:57 2010 No.1186927

Engines. How do they fucking work?
(pretty simple, but I'm still trying to think of something I know a lot about)

First, we have 2 stroke (or cycle) engines. These are found on weedeaters, dirtbikes, very old lawnmowers, some older outboards, and a few very old cars. As the name suggests, they have two strokes. On the up stroke of the piston, exhaust from the previous power stroke is ejected out the exhaust port as fresh air and gas mixture is simultaneously pulled in through the intake. This is achieved by fluid mechanic sorcery. Because of this, however, this makes two strokes very bitchy about exhaust and intake tuning. Specially designed exhaust pipes tuned properly to the engine can cause a wave of back pressure that helps compress the next charge, giving a gain in performance. Most of the time, though, they'll still run ok with a generic exhaust or none at all. Next, the downstroke occurs. The mixture of fuel and air is compressed into a small space and ignited by the spark plug. The piston is pushed upwards and the cycle repeats.

Anonymous Mon Jun 14 21:51:57 2010 No.1186928

Forgot the term, but the lungs are also controlled by levels of CO2 in the blood. (NOT O2!) At first, if CO2 levels are too HIGH, reponses are sent to the lungs to breathe more. If they are too LOW, responses are sent to the lungs to breathe less. If this fails, O2 comes into play. If O2 levels are too LOW, responses are sent to the lungs to breathe more. If O2 levels are too HIGH, responses are sent to the lungs to breathe less.
PROTIP: If you are dealing with an emphysema patient with difficulty breathing (likely) DO NOT, I repeat, DO NOT, blast him/her with O2, this will cause the patient to STOP BREATHING. Enjoy /sci/, I WORKED HARD ON THIS. (except the resp/metabolic acid/alkalosis.

Also, I apologize if anything is wrong (likely), since all of this is from the top of my head.

Anonymous Mon Jun 14 21:52:57 2010 No.1186931

>>1186927
Four stroke engines are more complicated. These are the basis of nearly all modern engines and are found in modern power equipment, cars, etc. Again, as the name implies, they operate on a cycle of 4 different strokes. First, the piston is raised and the intake valves are opened. The air and fuel mixture enters the cylinder. The valves close and the compression down stroke begins. The air is compressed and then ignited by the spark plug. The expanding gasses push the cylinder up, and then it comes down again. The Exhaust valves open and the exhaust is vented. The exhaust valves close and the stroke begins again with intake. Because this cycle is controlled by valves, the engine design is more complicated to accommodate the mechanics that control the valves.

Anonymous Mon Jun 14 21:52:57 2010 No.1186940

>>1186931

Now for the differences. Two stroke engines (simple ones at least) have no need for valves, and therefore no need for cams, lifters, pushrods, etc. This also means, though, that there's no oil sump to lubricate the engine. These engines, therefore, require lubricating oil to be mixed into the fuel. 4 strokes, on the other hand, do not require this. More advanced 2 stroke engines will have oil injection, so that you don't have to mix it yourself. Two stroke engines are also lighter and less complicated due to the fewer moving parts. They have greater power to weight and power density ratios than 4 strokes. 4 Strokes, on the other hand, are more reliable, more efficient, and have lower emissions. 4 Stroke engines require a larger flywheel to keep the engine turning over between more infrequent power strokes.
(Disclaimers)
These are just generalizations, however. You can find exceptions fairly easily. Also, there might be a 2 stroke engine in existence that does have valves and etc, but I'm discussing the most simple versions.

Oil Chem Mon Jun 14 22:00:33 2010 No.1186999 [DELETED]

Go to any news site and the following words get plastered on your face "Oil spill on the gulf of Mexico", "Oil gushing out at

2x the speed of light!" etc. And while that is all fine and dandy (politics >>new), I would simply like to inform you a bit

as to what "oil" is.

Now, obviously, oil isn't like the stuff you use to cook up your eggs(clear yellow) but you knew that already. So what then

is "oil"? Well, oil is a collective term used to identify a variety of organic compounds (atomic legos put together

essentially) as a result of decaying organisms and vasts amount of pressure (plus a couple of hundred of thousand of years).

These compounds are said to be "organic" simply because they are composed primarily of carbon (C) and, historically,

compounds derived from organisms all contained this element so the name stuck. Now, if these things are organic how come they

are not sold in your local super market as "green" foods? Because they are not. These things are simply compounds that

contain C, not that they are in the ordinary "organic" sense.

Now, semantics aside (and is important that you get the point from here on), these collections of carbohydrates can go from

simple molecules like ethanol, formic acid, methane, to large bulky things no sane chemist even bothers giving a formal name

(let's just call it mehline--OKAY) because they are so large and complex. As a result Oil is not a molecule or "a chemical"

but some hodgepudge of organic chemicals, kinds of like a veggy soup that can pretty much have anything and still be "veggy

soup" (no diced pizza though). So then what's the big deal, right? Well, something that contains so many different things to

pick from, all with a myriad of applications, and most which are not "cheap" in energetic and practical terms to synthesize,

is quite frankly black gold! But since saying so is not making so, allow me to explain in more detail.

Anonymous Mon Jun 14 22:01:35 2010 No.1187009 [DELETED]

>>1185430
Sorry for the long delay. You're correct, adenosine has to be given as an IV push followed by a fluid bolus to get it to the heart as quickly as possible. The drug has a half-life of 15-30 seconds once it's in the bloodstream, so if it's given too slowly it peters out before having the desired effect. On the other hand, sometimes the pause in the patient's heartbeat can last for upwards of 10 seconds, which is quite disturbing for the usually conscious patient.

>>1184646
To talk about brain aneurysms we first need to straighten out some commonly mistaken terminology. An aneurysm is an abnormal widening of a blood vessel, usually due to a weakening of or defect in the vessel wall. The cause can be congenital, trauma, or disease. Aneurysms can occur anywhere in the body, but are particularly worrisome in the brain or on major vessels in the chest, neck, or abdomen.

When most people think of an aneurysm, they are thinking of a ruptured aneurysm. An aneurysm itself is not necessarily dangerous and if it appears stable it will often be untreated because the risk of surgery outweighs the risk of rupture. But if an aneurysm ruptures, the obvious consequence is internal bleeding. In some cases this is no big deal, like a ruptured blood vessel in the eye. But if it's a big vessel like the aorta, a ruptured aneurysm can lead to death in minutes. In the brain, the concern is pressure. (continued)

Chem Mon Jun 14 22:02:57 2010 No.1187016

Go to any news site and the following words get plastered on your face "Oil spill on the gulf of Mexico", "Oil gushing out at 2x the speed of light!" etc. And while that is all fine and dandy (politics >>new), I would simply like to inform you a bit as to what "oil" is.

Now, obviously, oil isn't like the stuff you use to cook up your eggs(clear yellow) but you knew that already. So what then is "oil"? Well, oil is a collective term used to identify a variety of organic compounds (atomic legos put together essentially) as a result of decaying organisms and vasts amount of pressure (plus a couple of hundred of thousand of years). These compounds are said to be "organic" simply because they are composed primarily of carbon (C) and, historically, compounds derived from organisms all contained this element so the name stuck. Now, if these things are organic how come they are not sold in your local super market as "green" foods? Because they are not. These things are simply compounds that contain C, not that they are in the ordinary "organic" sense.

Now, semantics aside (and is important that you get the point from here on), these collections of carbohydrates can go from simple molecules like ethanol, formic acid, methane, to large bulky things no sane chemist even bothers giving a formal name (let's just call it mehline--OKAY) because they are so large and complex. As a result Oil is not a molecule or "a chemical" but some hodgepudge of organic chemicals, kinds of like a veggy soup that can pretty much have anything and still be "veggy soup" (no diced pizza though). So then what's the big deal, right? Well, something that contains so many different things to pick from, all with a myriad of applications, and most which are not "cheap" in energetic and practical terms to synthesize, is quite frankly black gold! But since saying so is not making so, allow me to explain in more detail.

(1/3)

Anonymous Mon Jun 14 22:03:57 2010 No.1187027
File: 40 KB, 500x435, aneurysm.jpg [View same] [iqdb] [saucenao] [google]

>>1185430
Sorry for the long delay. You're correct, adenosine has to be given as an IV push followed by a fluid bolus to get it to the heart as quickly as possible. The drug has a half-life of 15-30 seconds once it's in the bloodstream, so if it's given too slowly it peters out before having the desired effect. On the other hand, sometimes the pause in the patient's heartbeat can last for upwards of 10 seconds, which is quite disturbing for the usually conscious patient.

>>1184646
To talk about brain aneurysms we first need to straighten out some commonly mistaken terminology. An aneurysm is an abnormal widening of a blood vessel, usually due to a weakening of or defect in the vessel wall. The cause can be congenital, trauma, or disease. Aneurysms can occur anywhere in the body, but are particularly worrisome in the brain or on major vessels in the chest, neck, or abdomen.

When most people think of an aneurysm, they are thinking of a ruptured aneurysm. An aneurysm itself is not necessarily dangerous and if it appears stable it will often be untreated because the risk of surgery outweighs the risk of rupture. But if an aneurysm ruptures, the obvious consequence is internal bleeding. In some cases this is no big deal, like a ruptured blood vessel in the eye. But if it's a big vessel like the aorta, a ruptured aneurysm can lead to death in minutes. In the brain, the concern is pressure. (continued)

Oil Chem Mon Jun 14 22:05:57 2010 No.1187032

So yes, of course, Oil (in a way) is eventually used to power your car to get you to Wal-mart, but I mean, when was the last time you actually pumped in some black gunk down into your car? You didn't right (and if you did your shit is probably fucked by now), so clearly there must be a processing behind that. Well, yes, there is, and it's called "refining". Refining is quite literarly taking that black stuff and separating it nit for nack up to practicle levels in which they can be separated. In a more gentleman language, refining separates different molecular compounds into groups of compounds of similar physical or chemical properties depending on the refining process. The one that I'm familiar is simple fractional distillation which separates mixtures (like Oil) by boiling point. The fractional comes from the fact that this distillation (separation by boiling) is not continuous like you would if you were boiling pure water to purify it (water = 1 component--just boil and condense with ONE condenser) but it's done under reflux (constant boiling) and condensation is done by "fractions" or parts since different gases condense at different temperatures and each of these parts provide just that difference in temperature.

(2/4)

Oil Chem Mon Jun 14 22:05:57 2010 No.1187037

To illustrate it more clearly, take a tube and stand up straight and now pretend you are heating it from the bottom--how does the heat distribute? If you were "special" in school, you will probably touch the very bottom to find that you just lost your finger prints, but if you have common sense you'll probably know that the very top is cool while the very bottom is hot with the in-between kinda of in the middle. Now, how does this relate to gases--it's the same thing! Pretend gases boil from the heat on the bottom of the tube, however, as they rise things start to get chillax and those that condense at higher temperature (high boiling points) start condensing towards the lower part of the upper part of the tube (say A). On the other hand, the "anarchists" don't condense until much lower temperature so they'll rise almost to the very top (B--cooler) before they turn back to liquid. So then what do you do? Well, simply collect the liquids at different points A and B and all of a sudden--like magic--you've separated a bunch of things by collecting at different points along the length of the tube. So there, Voila, that's pretty much how fractional distillation works (although obviously the actual apparatus is drastically different than some "tube" although it works in principle the same way) and you've got yourself some delicious carbohydrates of different lengths, molecular weights, and different chemical properties--a lego mine!
(3/4)

Oil Chem Mon Jun 14 22:06:57 2010 No.1187042
File: 56 KB, 350x344, oil_products.jpg [View same] [iqdb] [saucenao] [google]

Since now we know how to separate different compounds from Oil, now what? Well, that's pretty much the start to every modern material and raw grade material to make things from your shoes to that thing you are staring at right now (the monitor)! Polymers (or in the more common way--plastics) are the main component of these, but polymers themselves are manufactured from scratch. The raw materials, the "monomers" the little tid-bits that repeat that repeat that repeat that repeat...(you get the point and the monomer by now) are a direct result from this fractional distillation and thus oil, although black and seemingly useless, provides the core material for their manufacture. In addition, these oil derivatives can also be used for the manufacture of other compounds that are useful for the cosmetic and pharmaceutical industry through the use of organic synthesis (take organic chemistry to learn more about this!) the exponential application to make anything material we want (almost, honest)! Gasoline (you've been wondering about that, I know) is but a mere part of the oil treasure that, while useful, it's a dead end for almost everything else (gasoline is composed of "saturated" carbohydrates that are pretty much only good as solvents or to BURNNNN. I won't deny though, that gas it's the one that will undoubtly get you the most cock-suckers for sure, but I think it besides the point.

So anyhow, I think I've outlined a ROUGH picture of the oil business. This is by no means complete, although I'd consider it fairly accurate. I've included a picture with all the cool looking geometry figures that represent molecules (can't go into that but I remembered they look awesome before I knew what they meant and even more awesome after I knew what they meant) just to show you what Oil does for you (aside from ruining your beach day). I hope this helps, or in the very least, informed a little.

(4/4)

Oil Chem Mon Jun 14 22:11:57 2010 No.1187074

>>1187042

Correction: I could not find the picture online (have it on an organic book) so instead included something else which isn't nearly as good. As you can see, this one focuses on the fuel process breakdown as opposed to all the other things I talked about which ARE emphisasized in the other diagram. This one makes it seem like "gas" is all there is to oil.

>>	Anonymous Mon Jun 14 22:13:57 2010 No.1187095 someone explain the differences between plasma, LCD, and LED tv's. i'm tired of hearing jackasses spit bullshit about the differences and what's the best vs what's not. i know they're always telling bullshit but i don't care to research myself.

Anonymous Mon Jun 14 22:15:57 2010 No.1187111

>>1186914
WAIT ONE MOTHERFUCKING SECOND.

You said you're an EMT there, but a high schooler in the previous post.

EXPLAIN THIS FAGGOTRY.

>>1187042
This might be better suited to engine dude, but what's the deal with the various numbers on the oil? I mean like the 89, 91, 93, whatever.

Anonymous Mon Jun 14 22:16:57 2010 No.1187122
File: 18 KB, 371x380, ICP.gif [View same] [iqdb] [saucenao] [google]

> Continued from 1187027

There is usually little risk of bleeding to death from a ruptured brain aneurysm. The risk is intercranial pressure. The brain has nowhere to go inside the skull and any fluids that get outside of the circulatory system get trapped in there too. This increases the pressure inside the skull and eventually starts forcing the base of the brain stem out through the foramen magnum (the hole on the bottom of the skull that the spinal cord passes through). Since the brain stem controls vital processes like breathing, squishing it isn't good. Increased intercranial pressure is a major concern with any kind of head injury because it can rapidly cause death.

A ruptured brain aneurysm is a double whammy- increased ICP from bleeding in the skull and the region of the brain that was previously supplied by the ruptured vessel is no longer getting an adequate blood supply. Which brings me to the next topic: strokes.

There are two types of strokes: obstructive/occlusive strokes and hemorrhagic strokes. Hemorrhagic stroke is just another name for a ruptured brain aneurysm. An occlusive/obstructive stroke (the words are interchangeable) is just like a heart attack but in the brain. A blood vessel becomes blocked for whatever reason, leading to tissue ischemia (lack of blood flow) and eventually tissue death. The mechanism for the blockage is the same as a heart attack. Usually a blood clot gets lodged in a narrow section of artery, though it can also be an air bubble or any piece of free tissue in the circulatory system.

The severity of a stroke is determined by its size (the amount of tissue it affects), its location, and the severity of the ischemia. Sometimes the blood flow returns on its own, in which case its called a transient ischemic attack (TIA).

Anonymous Mon Jun 14 22:18:57 2010 No.1187132

>>1187095
I'll give you the quick version.
Plasma works on principles similar to "traditional" TVs and CRT tubes. LCD works on the principle of light polarization, and LED is just a ton of fucking tiny led bulbs.

I'm not researched enough to give you pros and cons, but I can tell you this.

LED>LCD>Plasma
(in general)

Anonymous Mon Jun 14 22:23:57 2010 No.1187168

>>1187111

Those are "quality" numbers more formally known as the "octane" number. In a way, is to asses the purity of burn out of the gasoline composition (i.e. how easily does it combust and whats the yield of CO2 and H2O). The numbers are chosen such that 100 is some standard (I believe is an octane) that everything else is referenced to hence something like 90 octane is something that doesn't burn quite as readily and clean as that octane (could be something else, don't remember exactly) and something like 110 is better than octane etc. Gasoline grades (Premium regular blah bla) is based on this by the way.

Anonymous Mon Jun 14 22:23:57 2010 No.1187169

>>1187111
You mean for gasoline?
That's the octane rating. Originally, it had to do with the chemical octane that was present in the gasoline, but now it has a lot less to do with that chemical anymore.

The octane rating is a number which tells you how resistant the gasoline is to pre-detonation. High performance engines run at higher compression ratios and often higher temperatures, which runs the risk of having the gasoline suddenly detonate inside then engine at inopportune times or when it's supposed to but too violently. Higher octane rating gasoline burns slower and is less prone to sudden ignition, which is a must for high performance engines. Knocking (sometimes called pinging) can cause serious engine damage.

Lots of chemical additives can affect the octane rating. Lead, for example, was in gasoline as an anti-knock additive. Now we don't use it anymore because it fucked with catalytic converters and it's supposedly bad for the environment.

>>	Anonymous Mon Jun 14 22:25:57 2010 No.1187189 >>1187111 I am an EMT volunteer with the local Ambulance/ 911 crews and I'm in HS

>>	Kittens !!xU3iFlQ1LBB Mon Jun 14 22:28:57 2010 No.1187210 >>1187132 There's no such thing as an LED screen yet. The LED in "LED TV" refers to the backlight. Standard LCDs have a CF bulb. LED LCDs have... well... LEDs.

Anonymous Mon Jun 14 22:29:57 2010 No.1187225

>>1187169
Also, correction for myself.
>it has a lot less to do with that chemical anymore
Wasn't accurate. What I should have said is that the actual octane content of the gasoline isn't what solely determines the octane rating. Octane was used as a benchmark for predetonation resistance, and fuels are given ratings by determining what mixture of octane has identical characteristics. The important part is though because there are fuels that have better properties than octane, the methods for determining the rating have changed but the name has stuck.

Anonymous Mon Jun 14 22:30:57 2010 No.1187231

"Ye olde English" (linguistics is a science, right?)
First of all, old English, also known as Anglo-Saxon, is the language which was spoken in England prior to the Norman Conquest of 1066. It then morphed into Middle English under the influence of Norman French.

What I actually plan to talk about would be more correctly referred to as early modern English, and is frequently called Shakespearean or Elizabethan English. It's the kind you find in the King James Bible, with all the now-archaic thee's and thou's. Problem is, a lot of people don't know how these words were actually used, and might say such nonsense as "I hate thou!".

To explain, let's take the first person pronouns as an example: I, me, we, and us. 'I' and 'we' are nominative, so you could say 'I/we got up and ran'. 'Me' and 'us' are the objective case, for sentences like "The dog suddenly attacked me/us". For the 2nd person, we use 'you' for all these cases. How boring. (continued)

>>	Anonymous Mon Jun 14 22:30:57 2010 No.1187232 >>1187210 Ah, my mistake. Thanks.

Anonymous Mon Jun 14 22:31:57 2010 No.1187243

>>1187231 (part 2/2)
In Elizabethan English, the 2nd person pronouns were 'thou', 'thee', 'ye', and 'you'. 'Thou' is singular and nominative, and verbs in the second person singular usually ended with 'st'. Example: 'Thou trollest' or 'What dost thou want'. 'Thee' is singular and objective. Examples: 'I despise thee' or 'He pwn3d thee, novice!' 'Ye' is plural and nominative. "Ye (meaning more than one person) are the cancer that is killing /b/." And finally, 'you' was only used as the plural, objective case, as in "I'll kill you all!".

The usage of the plural forms as a sign of respect became more common as time went on, largely due to the French influence at the time. 'Thou' and 'thee' became reserved for close friends, and in some contexts came off as rude. Eventually they fell out of use entirely, being completely replaced by 'you'.

Also note that the 'ye' in 'ye olde English' has nothing to do with the personal pronoun. It's simply how medieval printing presses represented the letter 'thorn', with has since been replaced by the combination 'th'. So in this context 'ye' is 'the'.

>>	Anonymous Mon Jun 14 22:34:57 2010 No.1187269 >'ye' in 'ye olde English' has nothing to do with the personal pronoun. It's simply how medieval printing presses represented the letter 'thorn', with has since been replaced by the combination 'th'. So in this context 'ye' is 'the'. Mind = blown

>>	Anonymous Mon Jun 14 22:37:57 2010 No.1187291 Just finished up my electrocardiography certification test last week. Good thread. Well done, Op.

Anonymous Mon Jun 14 22:38:45 2010 No.1187293 [DELETED]

>>1181167
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>>	Anonymous Mon Jun 14 22:53:57 2010 No.1187420 >>1187291 What does that entail, exactly? Can you teach us a tiny bit?

>>	Anonymous Mon Jun 14 23:20:57 2010 No.1187691 Bump

>>	Anonymous Mon Jun 14 23:27:57 2010 No.1187737 i can has bump?

>>	Anonymous Mon Jun 14 23:30:57 2010 No.1187754 File: 78 KB, 526x338, im_a_shark_cat.jpg [View same] [iqdb] [saucenao] [google] omg i am skinny with a heart...i will die!!!!!!!!!!! i feel asleep now

>>	Anonymous Mon Jun 14 23:40:57 2010 No.1187831 Bump

>>	Anonymous Mon Jun 14 23:55:57 2010 No.1187968 Archive this plz (preferably after some more quality posts), I need to re-read it when I'm not high so I could memorize something maybe. I fucking love you guys.

>>	Anonymous Tue Jun 15 00:01:57 2010 No.1188029 >>1187968 I suggested that, but no one seemed to do it. Myself included...

>>	Anonymous Tue Jun 15 00:06:57 2010 No.1188067 http://4chanarchive.org/ Request Interface ID=1181171

Anonymous Tue Jun 15 00:08:57 2010 No.1188078

>>1187231
>>1187243

Yeah, linguistics! Dunno if it's a "science" per se, but hey, this is a "discuss ANYTHING" thread, now isn't it?

I'm going to talk about the history of the word "ain't." But first, let's look at the "to be + not" verb conjugations in standard English:
We have "aren't" and "isn't." "Aren't" is used with the second person pronoun (you), and the plural pronouns (we, they, you [all]), while "isn't" is only used with 3rd person singular (he/she/it). However, we simply do not have a contraction for first person singular! We can say "I'm not," but there's no "I amn't." Well, that's what "ain't" used to be. For example, "I ain't trolling" is completely correct. Or, used to be correct, I should say.

Actually, "amn't" used to be commonly used, appearing in the 1600's or so. It morphed into "an't" simply because people didn't like the similarly sounding letters m and n side by side. The "a" was often pronounced as "ay," leading to the eventual respelling of "an't" to "ain't."
For a time, "ain't" was a perfectly acceptable contraction for "am not," but in the 18th and 19th centuries, people of the lower class in England started using it incorrectly. In common speech, "ain't" started to take the place of "isn't," "aren't," and even "hasn't" and "haven't."
Ex.: I ain't got your money! (have not)
She ain't here yet! (isn't)
Damn, you ain't joking! (are not)

Well, the high class grammarians of the late 1800s didn't like this, declaring the misuse of "ain't" as vulgar and low-class. This led to a negative connotation for the word "ain't" in general, even when used in it's correct state as a contraction for "am not." So, the educated stopped using "ain't" for "am not," but the uneducated never stopped using "ain't" for... well, everything else.

>>	Anonymous Tue Jun 15 00:09:57 2010 No.1188086 EVERYONE READING THIS GET THIS SHIT ARCHIVED.

>>	Anonymous Tue Jun 15 00:16:57 2010 No.1188125 Archived. Someone double check please. I used proxies to get most of them in. I don't trust other people sometimes. You want something done, you gotta do it yourself!

>>	Anonymous Tue Jun 15 00:17:57 2010 No.1188129 File: 24 KB, 358x400, 1258434900295.jpg [View same] [iqdb] [saucenao] [google] >>1188086 "Congrats, your request has just triggered the archival process for thread 1181171"

>>	Anonymous Tue Jun 15 00:17:57 2010 No.1188131 >>1188129 You're the guy who did the final one. Good job.

Anonymous Tue Jun 15 00:18:15 2010 No.1188142 [DELETED]

File: 287 KB, 700x454, 1544969275.jpg [View same] [iqdb] [saucenao] [google]

Do you guys like OPERATORS? How about OPERATORS OPERATING OPERATIONALLY? Well, good news, because there's a site that's dedicated to OPERATORS like you --OPERATORchan!

Join us for 18 boards of AWESOME weapons discussion. OPERATORchan is an imageboard totally focused around weapons, militaries and similar topics. Talk about gear, Airsoft, weapons; even survival, food & hunting in an OPERATOR-friendly environment. Visit us today! You have nothing to lose, and a great board to gain!

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See you there!
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>>	Anonymous Tue Jun 15 00:18:57 2010 No.1188138 Somebody cliffs this shit

>>	Anonymous Tue Jun 15 00:19:57 2010 No.1188148 >>1188138 Knowledge can not and should not be shortened. Read the thread (the parts where I'm not bitching) and learn.

>>	RoboMendel !!IsknZSzwKtJ Tue Jun 15 00:22:57 2010 No.1188163 I highly enjoyed this thread, and if I was not a chemistry major with no interesting knowledge to contribute I would gladly contribute something.

Anonymous Tue Jun 15 00:23:57 2010 No.1188174
File: 25 KB, 640x480, superultimaterageface.jpg [View same] [iqdb] [saucenao] [google]

>>1188078
> This led to a negative connotation for the word "ain't" in general, even when used in it's correct state as a contraction for "am not."
> even when used in it's correct state
> in it's correct state
> it's
> it is

:(______________________________)

You'd better come up with some linguistic justification about how language is a communication medium apt to contain encoding errors that don't significantly alter the overall message as long as the receiver understands REALLY QUICK NOW, buddy.......

Anonymous Tue Jun 15 00:24:15 2010 No.1188180 [DELETED]

File: 1.99 MB, 1862x1397, 1361684471.jpg [View same] [iqdb] [saucenao] [google]

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Join us for 18 boards of AWESOME weapons discussion. OPERATORchan is an imageboard totally focused around weapons, militaries and similar topics. Talk about gear, Airsoft, weapons; even survival, food & hunting in an OPERATOR-friendly environment. Visit us today! You have nothing to lose, and a great board to gain!

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>>	Anonymous Tue Jun 15 00:28:57 2010 No.1188209 I was reading an article recently that said carbs are worse for you than saturated fats. While saturated fats increase LDL levels, HDL levels are also increased.

>>	Anonymous Tue Jun 15 00:29:57 2010 No.1188219 >>1188163 Come on, think of something!

>>	Anonymous Tue Jun 15 00:31:57 2010 No.1188227 >>1188174 OH SHI- Did I... Did I really do that?!? Jesus fucking christ. That's one of my biggest grammatical pet peeves, too. I'm gonna go to sleep now. ;_;

>>	RoboMendel !!IsknZSzwKtJ Tue Jun 15 00:31:57 2010 No.1188229 >>1188219 I could explain about instruments, but I only have general knowledge in all areas inorg, orgo, instrumentation and techniques.

>>	Anonymous Tue Jun 15 00:32:57 2010 No.1188232 >>1188229 Go for it, I'm a 2nd year trombone fag and I'm pretty dam average. I'm sure some people might be interested in it.

>>	Anonymous Tue Jun 15 00:34:57 2010 No.1188242 >>1188209 lol recently? Atkins has been saying that for decades and so have many others.

Anonymous Tue Jun 15 00:37:57 2010 No.1188259

I guess I'll contribute. I'm primarily a mathfag, but since there's really no way to explain in layman's terms I'll just talk about music theory. It's a deep field, with lots of heavy mathematics (fourier analysis), so I'll start by answering one simple question:

Why do different instruments so different?

It sounds like a simple question, but I depends of the wave that the instrument produces. common depictions of sound are often just a simple sound wave. That kind of wave vibrates at only one frequency, and is a pure tone. The truth is that most sounds that occur in the "real" world are many of these pure tones put together. Why don't we hear many different frequency sounds coming from a single source?

Cont.

Anonymous Tue Jun 15 00:38:15 2010 No.1188262 [DELETED]

File: 88 KB, 700x454, 1972536041.jpg [View same] [iqdb] [saucenao] [google]

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Anonymous Tue Jun 15 00:38:57 2010 No.1188264

I have really enjoyed reading all this stuff about cardiovascular medicine, particularly because I work on the Tissue Engineering of Vascular Grafts.

A lot of you may have heard in the news about Stem Cells and their therapeutic potential in producing various body parts for transplantation. This idea forms the basis of regenerative medicine, at least as far as I see it feasible. Now, stem cells are not necessarily the only tool available to create tissues "in vitro" (outside the body). Let's say you wanted to grow an Artery. You will need the cells that make up the three tissue layers of the artery (Epithelial, Smooth Muscle cells & Fibroblasts particularly), a "Scaffold" for growing the cells in (I like Collagen, which is essentially Jello) and a machine called a "Bioreactor" which provides a sterile environment to grow the cells/tissue in. Mix the cells with the jello to create the right structure (Epithelial on the inside, Smooth muscle in the middle and Fibroblasts on the outside) and let it gel/polymerize. Put it in the Bioreactor which keeps it at 37C, feeds the tissue fresh media (just like a blood supply would) and provide a cyclic mechanical stimulation to the artery (stretch it). The first time this was tried was 1986 by two guys named Weinberg & Bell. The reason why the artery was not suitable for transplant, then or now, is that the arteries produced in the lab this way do not have the same mechanical properties as the arteries produced "in vivo" (in the body). Obviously it is a very complicated problem, seeing as it has been decades and we still don't have a solution!

Cubedude !LoLMoDTrip Tue Jun 15 00:39:57 2010 No.1188271

I'd like to talk about the science of the Orgasm.

The human orgasm is an amasing thing, scientists are still working towards explaining all of it but there are many reactions and effects that are still observed that we simply have no explaination for.

to learn about the orgasm you have to examine the central nervous system, the network of pathways that all the orders pass through and the way in which it interacts with the brain.

First, stimulating the genitals sends electrical impulses along three main paths: the pelvic, hypogastric and pudendal nerves. Then these signals enter the spinal cord at the base of the spine and travel to the brain regions that respond to genital sensations. Then other parts of the brain leap into action sending signals to the body, like :lubricate the vagina, stiffen the penis, pump blood harder, breathe faster.

The intensity builds to a crescendo, and suddenly the tension is released in an explosive rush. The heart rate doubles. In women, the uterus contracts rhythmically; in men, sperm-carrying semen is propelled out of the body.

Seems pretty simple, But that is just the front page of the book, Just muscular contractions. The weird thing is the fact that the brain also takes all these signals and tells you it feels bloody amasing.

1/2

Cubedude !LoLMoDTrip Tue Jun 15 00:40:57 2010 No.1188282

They found that orgasms elicit strong activity in the nucleus accumbens, the reward center, which also lights up in response to nicotine, chocolate, cocaine and music; in the cerebellum, which helps coordinate muscle tension; and parts of the hypothalamus, which releases oxytocin, the trust and social-bonding hormone.
Intriguingly, areas of the cortex that respond to pain also responded during orgasm.
The amygdala, the brain's emotional center, and the hippocampus, which deals with memory, light up too. This helps explain a weird and rare medical mystery: When epileptic seizures start in these areas then the affected person can actually seem to have an orgasm (Amusingly termed Orgasmic Pauses)

Also many things seem to shut down, The area dealing with inhibitions (the lateral orbitofrontal cortex) shuts down about 5-10 seconds before and can take up to 10 mins to start up again, depending on the person.
The temporal lobes go into inactive mode to, and tests have shown that this is directly related to the female orgasm and the longer the lobes are shut down the stronger the orgasm seems to get.

This entire process spans only a few seconds, in which a huge portion of the human brain seems to flare up like a flashlight.

A wonderful ballet of chemicals with a huge crash of drums at the end. All so you can shoot a load and feel good doing it. Don't waste your brain guys, have more sex!

2/2

Anonymous Tue Jun 15 00:41:57 2010 No.1188290

Black holes are formed when high density stars fuse all of their hydrogen atoms in the core into iron. Iron does not easily form other elements, so the fusion stops.
I'm not too sure on the next part, I think that the iron is expelled when the star explodes (not a supernova in this case, but a hypernova). Because the center of the star is now vacant, its massive gravity causes it to implode, creating a super-dense volume of hydrogen.
Over time, more matter is added to the collection, which is easily done because it has the same mass while allowing matter to come closer to the center of gravity. The new matter is also compressed, etc.

Anonymous Tue Jun 15 00:43:15 2010 No.1188299 [DELETED]

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RoboMendel !!IsknZSzwKtJ Tue Jun 15 00:43:57 2010 No.1188296
File: 80 KB, 745x540, Picture1.png [View same] [iqdb] [saucenao] [google]

High Performance Liquid Chromatography (HPLC) is a technique used frequently in chemistry to separate and then analyze components of a particular solution.

The real value of this technique is that you can inject a complex solution with many different molecules into the instrument and separate each component so that each can be analyzed by a specific detector at the end of the process.

Attached is a picture of a fairly standard HPLC instrument. The basic premise of the workings is that you have a sample vial of your unknown solution which is injected in addition to a solvent to a chromatography column which can be filled with tiny (nanometer) particles of different compositions. When the solvent and unknown solution mixture hits the column the unknown solution will instantly begin to partition in the column. When the solution partitions, some of the unknown compounds will remain "stationary" by absorbing or adsorbing onto the column while other compounds transition between phases more quickly and move down the column at a faster rate of speed. What this means in simple terms is that certain molecules will come out of the end of the chromatography column faster than others and depending on column conditions, you can efficiently separate every component of your unknown solution.
Part 1 of ?

Anonymous Tue Jun 15 00:43:57 2010 No.1188298

Math up in here.

A lot of people like to post questions regarding 0 times some real number, and there are loads of images about OH LAWDY, someone divided by zero.

This is all covered in an area of math known as Modern (or abstract) Algebra. Essentially, we look at the operations that everyone knows on the real numbers, and try to extend them to other sets of numbers. We'll call these sets GROUPS.

So pick some set. We can make this set a group if we define an operation that takes two elements of this set and gives us another element. This property is called closure. We also require this operation to be associative, have an identity element (think 1, for multiplication on R, or 0 for addition on R) and have inverses (I.E. if * is our operation, for ever a in our set, we have a b such that a*b=1)

Now, groups only need one operation. Also note i haven't required this operation to be commutative. A group with a commutative operation is called Abelian.

We can add more operations with slightly more restrictions, if we talk about rings, or fields, but that's the gist.

Anonymous Tue Jun 15 00:44:57 2010 No.1188308
File: 78 KB, 460x300, ekg-basic.jpg [View same] [iqdb] [saucenao] [google]

>>1187420
I'm not that person, but I'll start in case he isn't around anymore. He can add to what I say or pick up where I leave off.

Everybody probably already knows that an ECG (EKG if you like) is a tracing of the heart's electrical activity. Lets go through the basic anatomy of the heart's electrical system first. The main components are the SA node, AV node, right and left bundle branches (there are actually two left bundle branches, anterior and posterior), and purkinje fibers. The SA node is the heart's main pacemaker and in a normally functioning heart all electrical impulses start there. When the AV node fires, it stimulates contraction of the right and left atria. The impulse then travels to the AV node, where it is briefly delayed to give time for the ventricles to fill with blood. It then proceeds rapidly through the bundle branches and to the purkinje fibers where it stimulates ventricular contraction.

Each of these steps are shows as waves on the ECG. The ECG doesn't actually show the impulses from the nodes, it shows the depolarization (contraction) and repolarization (rest/reset) of cardiac muscle cells en masse.

The first wave you see on a normal ECG is the P wave. This represents the contraction of the atria. The next three waves- Q, R, and S, represent the contraction of the ventricles. They are usually referred to as a group called the QRS complex. The next wave is the T wave, which represents the repolarization (relax/reset) of the ventricles. You can't normally see the repolarization wave for the atria because it is very weak and buried under the QRS complex.

Because the strip moves at a specific speed, you can measure the time intervals between each of these events by measuring the distance between them. Each small box on the ECG paper is 0.04 seconds.

Anonymous Tue Jun 15 00:45:57 2010 No.1188313

>>1188259

The reason only one sound is perceived is because the auditory cortex of your brain encounters harmonics (The tones are called harmonics) so often that you only perceive the lowest frequency harmonic, often called the fundamental frequency. The pitches of the second and up harmonics are all integer multiples of the frequency of the first harmonic (1st harmonic frequency = 100hz -> 2nd = 200hz, 3rd = 300hz...). Even though theses frequencies are pretty much set in that pattern, their relative volumes change greatly between the source, and they are called the overtone profile, the main reason why things sound differently. The general rule of thumb is that the lower harmonics have a higher amplitude the higher ones, which is why most instruments have a wave that looks some what like a saw tooth form.

Cont.

Anonymous Tue Jun 15 00:48:15 2010 No.1188325 [DELETED]

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Anonymous Tue Jun 15 00:48:57 2010 No.1188327
File: 92 KB, 1056x816, Basic EKG Flowchart.png [View same] [iqdb] [saucenao] [google]

>> Continued from 1188308
There are hundreds of types of dysrhythmia, so it's not really reasonable to go into detail about them in this thread. I'll just briefly go over some of the basic things to look for when evaluating an ECG.

The first is regularity. If the rhythm is regular, the distance (time) between each QRS complex is the same. If it's irregular, the time between beats varies. The next is rate, how many times per second is the heart beating- represented by how many QRS complexes are present per second. These two things can also be determined by feeling the patient's pulse.

The next thing is whether P waves are present. If so, is there one and only one for each QRS and do they come at the appropriate distance in front of each QRS. This tells you if the beat is originating in the SA node or somewhere else.

From here it really depends on what you find in the previous points, but some of the other things you would look for include extra beats, which show up as one or more irregular beats in a series of otherwise regular beats. When people say they felt their heart "skip a beat" it is usually actually an extra beat. Another thing would be the shape of the QRS complex. They should be narrow and identical from beat to beat. Wide QRSs or ones that vary substantially from beat to beat indicate various conduction problems.

Pic is a flowchart showing the steps to identify the basic set of rhythms that are required as part of the advanced cardiac life support standards. It's a little old, so it may be out of date.

Anonymous Tue Jun 15 00:51:57 2010 No.1188352

http://www.brainstatetech.com/
Can we talk about these brain state synchronization courses please? My parents just cut me off because I refused to attend these courses because I said they were bullshit, and I would appreciate it if someone who knows about these things could explain to me that I was right in calling them out as shysters.

RoboMendel !!IsknZSzwKtJ Tue Jun 15 00:52:57 2010 No.1188357

>>1188296

Now that you have ever separate molecule coming out at a different point in time after the time of injection, you will run each of the solutes (solution leaving the column) through a detector. Depending on your budget and your specific detection needs, you will have different detectors on the ends of your column. A frequently used detector is a UV/Vis photodiode array (pictured) or a mass spectrometer which is quite a deal more expensive and specialized, but provides much more specific information.

The UV/Vis photodiode array works by shining light through your eluate (solute) and seeing how each wavelength of light is absorbed by the sample. Since it is a photodiode array, an entire spectrum (lets say 200 to 700 nm) can be taken every time the array is turned on (for example an entire spectrum of data every 0.1 second.)

Basically, when you can get an entire light spectrum of the absorbed wavelengths every second, you can compare the solute that is flowing through at that instant in time through the detector to the wavelengths being absorbed and gain useful knowledge as to the composition of one particular molecule in your unknown solution.

A mass spectrometer basically works by ionizing (breaking) the molecule passing through the detector into smaller pieces and then using electric and magnetic fields to seperate the different sized pieces for counting. For example, if a molecule with a mass to charge (m/z) ratio of 331.232351832 were to be detected by your mass spectrometer you could calculate the exact elemental composition of the molecule flowing through the detector at that point in time, which is VERY useful at determining the overall structure of the molecule.

These are just two of the MANY detectors used on HPLC and GC (gas) instruments, and to be honest, they are quite fun to use.

>>	RoboMendel !!IsknZSzwKtJ Tue Jun 15 00:53:57 2010 No.1188360 File: 33 KB, 564x457, Picture2.jpg [View same] [iqdb] [saucenao] [google] >>1188357 Forgot photodiode array picture!

Anonymous Tue Jun 15 00:54:57 2010 No.1188373

>>1188313

For example, clarinets have relatively high amplitudes at the odd harmonics, caused by the bell at their ends, but trumpets have higher amplitudes at the even harmonics. This difference is why they sound so distinct. Additionally, so instruments only follow an approximations of the harmonic frequency rule (drums, timpani, and to a lesser extent, pianos and plucked violins). These instruments are said to be in-harmonic. It's often difficult to tune them because the unusual harmonics fuck up how we perceive them. Some instruments, like flutes, follow the formula well, which is why they sound "pure". By the way, there are different nomenclatures about the harmonics. Most musicians simply number the different tones, like I did (1st, 2nd,3rd... harmonics), but most acousto-physicists call the lowest frequency the "fundamental frequency, and the rest are referred to as the 1st, 2nd, 3rd... overtones. So now you know most of why things sound different.

Cont.

>>	Anonymous Tue Jun 15 00:54:57 2010 No.1188376 >>1188259 I take your question as a lesson to take Fourier analysis with a grain of salt. Consider human perception as a reality you want to understand first, then math may be useful in modeling perception second.

>>	Anonymous Tue Jun 15 00:59:57 2010 No.1188395 i kind of want to archive this. random info thread

Anonymous Tue Jun 15 01:00:57 2010 No.1188405

>>1188373

When a note is struck there are somethings called the attack and flux fazes. The attack faze is the brief period when energy is first introduced into a source. During this times, the harmonics are all kinds of fucked up. It's a brief period, but it really makes a big difference. The flux faze is after the source has reached stability and is steadily loosing energy (the volume is going down). During this time, not all harmonics are losing amplitude at the same rate. Some persist longer than others. This is why sometimes you hear an odd higher-than-normal ringing as an instrument is fading. One of the higher harmonics is decaying slower than the others.

Done. If any of you have any other questions about music theory, shoot.

Anonymous Tue Jun 15 01:02:46 2010 No.1188419 [DELETED]

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>>	Anonymous Tue Jun 15 01:03:57 2010 No.1188427 >>1188376 For some reason I can't quite understand what you are saying. Can you clarify?

Anonymous Tue Jun 15 01:04:57 2010 No.1188434

>>1188259

I love you and your mathematical explanation of music. Do you know how to explain why some intervals are generally gross-sounding (tritone) and why some sound nice (octaves, thirds, fifths). I read an explanation once in the book "This is Your Brain on Music" but I've forgotten since then. Sounds kinda like the stuff you're talking about.

Anonymous Tue Jun 15 01:05:57 2010 No.1188441
File: 220 KB, 878x738, 12-lead-overview.jpg [View same] [iqdb] [saucenao] [google]

>> Continued from 1188327

Now, why is this useful? Various problems with the heart that are not directly related to electrical conduction also show up as conduction problems. For example, ischemic muscle (as in a heart attack) does not respond as quickly and retards the progress of depolarization/repolarization signals. This shows up as abnormal deflection and width of waves. Many other conditions can be identified in a similar way.

By using multiple leads, it's possible to build a 3D image of the electrical function of the heart. This makes it possible to not just identify the presence of a problem, but to pinpoint its location. For example, using a 12 lead ECG on a heart attack patient it's often possible to identify which artery is the culprit and in what region of the heart is most affected.

Pic shows a normal 12 lead ECG on the bottom. Notice the lead labels at the top left of each strip. They are I, II, III (these are the limb leads) then aVR, aVL, aVF (these are augmented limb leads), then V1-V6 (the precordial leads). The top two images show the placement of the precordial leads and how they are looking at different parts of the heart.

Anonymous Tue Jun 15 01:07:57 2010 No.1188451

>>1187231
>>1188078
Fuck yeah linguistics. I'm here to teach you all some shit about the Chinese languages.

First, notice how I said languages, plural? That's because, contrary to popular opinion, there are several spoken Chinese languages. The Ethnologue (basically, a gigantic compendium of the world's languages) lists 14 spoken languages, the largest being Mandarin, Wu, Cantonese, and Min Nan. (Note: the Chinese perceive only one written language, since speakers of two different spoken Chinese languages can understand each other relatively well in writing)

When someone says that they are learning Chinese, they most likely mean that they are learning Standard Mandarin. This bad motherfucker is known by over 1 billion people, making it THE #1 language in terms of speakers. It's also the official language of the People's Republic of China (aka Mainland China), which means that Mandarin, opportunistically speaking, is the most viable of the Chinese languages. Finally, Mandarin is the largest of the languages geography-wise; it covers the vast majority of eastern China, not including its southeastern corner.

Wu is the next-largest of the languages, with about 90 million speakers. It's most spoken along the center of China's eastern seaboard, in Zhejiang, and the independent city of Shanghai, although it can also be found in southern Jiangsu. Within the Chinese languages, Wu is noted for its voiced consonants, which the other languages lack; loosely speaking, voiced consonants are those with a "dark" sound, like d, z, v, and b.

Anonymous Tue Jun 15 01:09:46 2010 No.1188471 [DELETED]

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>>	Anonymous Tue Jun 15 01:12:57 2010 No.1188482 can someone explain deja vu and jamais vu? is it just perception weird stuff? is there some kind of biochemical process in the brain that makes me think, "hey, I just experienced this..." or something?

>>	Anonymous Tue Jun 15 01:13:57 2010 No.1188490 booga

Anonymous Tue Jun 15 01:15:46 2010 No.1188499 [DELETED]

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Anonymous Tue Jun 15 01:17:57 2010 No.1188506

>>1188434
I've read that book too, but I lent to a friend and he never returned it. Anyway, I remember the exact reason for consonance/dissonance, but I do know this. All the just intervals are derived from the harmonic series. For example, the the ratio of frequencies of the 1st and 3rd harmonics is 3:1. This is a perfect fifth and an octave.

Ratios between harmonics:
1st and 2nd = 2:1 = Octave
1st and 3rd = 3:1 = Octave + Perfect Fifth
1st and 4th = 4:1 = 2 Octaves
1st and 5th = 5:1 = Major 3rd and 2 Octaves
...
1st and 9th = 9:1 = Major Second and 3 Octaves.
...
1st and 11th = 11:1 Tritone and 3 octaves

The lower the harmonic it is based of of, the more "basic" and consonant the interval. The higher up, the more dissonant. I know the minor second, the most dissonant interval have a crazy stupid ratio (looking up).

Anonymous Tue Jun 15 01:19:46 2010 No.1188522 [DELETED]

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>>	Anonymous Tue Jun 15 01:19:57 2010 No.1188519 >>1188434 >>1188506 Fund it. That ratio between the 1st and 17th harmonics is 17:1, which is a minor second and 4 octaves.

Anonymous Tue Jun 15 01:20:57 2010 No.1188525

GENE EXPRESSION 1:

Like a guy said earlier, your DNA holds a massive store of information. However, when you have multicellular organisms, where you're diving up jobs to specialized cells (Recall the earlier econ guy!), the cells are not going to need every piece of information.

By this means, the cell has ways of switching certain genes "on" and "off". You might wonder, "How can a cell, that doesn't have a brain and therefore the ability to make decisions or think, know when to turn genes on or off?"

The thing is, the system needs to be arranged in a way so that it happens automatically. This can be quite easily illustrated by examining the expression of the genes which control lactose metabolism in E.coli.

Anonymous Tue Jun 15 01:20:57 2010 No.1188529

The promoter is a sequence that lies "upstream" from a gene and regulates it's expression. In order for a specific gene to be expressed, it's "product" needs to get made. And it gets made by having the gene undergo a process called transcription, which makes an RNA copy of the gene that the cell uses to actually build whatever it encodes for, most frequently a protein of some sort, in a process called translation.

The enzyme responsible for reading the DNA and synthesizing this RNA, RNA polymerase, needs to know where to start. Or, to think of it another way, it needs to know where to "land" on the DNA in order to start transcribing the RNA. Having a bigger "landing strip" allows for the more successful binding of the RNAP to the promoter in order to transcribe the gene, thus making it's product, thus expressing the gene.

Anonymous Tue Jun 15 01:21:57 2010 No.1188536

It can get a bit more complicated than that: The RNAP doesn't always perfectly bind to the promoter every time it comes near it, but the cell does this for a reason. For example, there's proteins which will bind to the promoter or part of it in order to block the RNAP from working, a way of shutting a gene "off". Or, it could have the opposite effect: A protein on the promoter or somewhere nearby could make the RNAP bind to the promoter much more reliably, putting it onto a sort of "on" state. By this means, by keeping the promoter "clear", you can get a sort of "not completely on, but not completely off" either situation as well, called the "basal" state.

To give some arbitrary numbers, in the basal state the RNAP might bind to the promoter maybe 50% of the time. However, with the inhibitor protein on the promoter, it would be 0% or 100% if vice-versa. Having a bigger or smaller promoter would increase/decrease the "basal" state percentages up and down, respectively.

For example, with a really big promoter, you might have 75% chance of the RNAP binding while in the basal state.

Many genes are switched "on" and "off" by environmental factors.

For example, E. coli normally metabolizes glucose for it's energy. However, it's also capable of metabolizing lactose when it needs to, but normally it keeps this gene off.

However, if the E. coli comes into contact with lactose, some of the lactose will bind to the protein that's sitting on the promoter associated with the production of beta-galactosidase, which digests lactose. This binding causes the protein to leave the promoter, allowing the cell to properly synthesize the beta-galactosidase so that it can start digesting the lactose it's finding. As soon as the lactose runs out, the protein goes back onto the promoter to switch it off again..

Anonymous Tue Jun 15 01:21:57 2010 No.1188540

If there's LOTS of lactose around, a different protein binds to a nearby spot on the gene where the beta-galactosidase is coded causing the gene to be switched "on".

BY this means, you can see how your physical environment is capable of directly altering the way your genes are expressed, so any sort of eugenics based purely on genetic sequences would be flawed, to say the least, because your environment is just as important in the expression of many genes as what is in the gene itself.

Essentially, a clear differentiation needs to be made between your GENOTYPE (What is encoded into your genes) and your PHENOTYPE (Which is essentially HOW your genes are being actually expressed, or used).

Nurture vs. Nature, really. All E. coli have the GENOTYPE for lactose digestion, but it's only in the presence of lactose itself will it have the PHENOTYPE for lactose digestion.

For those interested:

If there's glucose, but not lactose, the lac operon (which is the set of genes associated with lactose digestion, including the one for beta-galactosidase) is switched OFF.

If there's both glucose and lactose, the lac operon is put into it's BASAL STATE.

If there's lactose but not glucose, the lac operon is switched ON.

Anonymous Tue Jun 15 01:24:57 2010 No.1188555

>>1188451
Part two.

Cantonese, aka Yue, is the third largest of the languages, totalling to about 55.5-70 million native speakers (for comparison, Italian is thought to have about 60 million native speakers. It is most widely spoken along China's southern seaboard, within the provinces of Guangdong and Guangxi, along with the Special Administrative Regions of Hong Kong and Macau. Cantonese has 6 different tones that can distinguish words, although it is sometimes said to have up to 11 tones (Mandarin has 5).

The fourth largest Chinese language is Min Nan, with about 49 million speakers. It's most commonly spoken in Taiwan, its neighboring province of Fujian, and the island of Hainan. Min Nan has up to 6 tones.

And now I'm tired and off to bed. It probably got long-winded at the end, but I don't give a shit.

tl;dr: Chinese is not a motherfucking language.

Anonymous Tue Jun 15 01:27:46 2010 No.1188572 [DELETED]

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Anonymous Tue Jun 15 01:27:57 2010 No.1188575

OP here. I'm happy that my thread is successful and all, but...

Well, it's getting a bit hard to understand this stuff. Part of this thread is that it's suppose to be mostly accessible. I tried to define as many things as I could in my stuff.

The stuff with the chromatography and the harmonic stuff lost me completely.

Anonymous Tue Jun 15 01:28:57 2010 No.1188581

>>1188525
>>1188529
>>1188536

God damn you put effort into this. Did you know that DNA is arranged into a space filling filling curve called a Peano Curve. It is, mathematically speaking, the most efficient way possible to fill space with a strand. Shit like this almost makes me believe in intelligent design

Anonymous Tue Jun 15 01:31:46 2010 No.1188599 [DELETED]

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>>	Anonymous Tue Jun 15 01:31:57 2010 No.1188595 >>1188575 If you have any questions about the harmonic stuff I'd be more than happy to answer. Taking time to educate on stranger is an infinitely better use of my time than spending all night jacking off on /s/.

Anonymous Tue Jun 15 01:33:57 2010 No.1188606

>>1188595
Well, it's just that this is a field with which I, and I bet most anons, have no experience with. You talk like you expect us to know must of this.

Keep in mind, it's starting to get late, and the effects of the caffeine are wearing off.

Hey, someone want to answer how caffeine and stuff affects the brain?

Anonymous Tue Jun 15 01:36:57 2010 No.1188627

Yes, it is uncanny how efficient and amazing biological machinery works, but before you go subscribing to Intelligent Design, remember that this system has had 3.5 billion years or more to perfect itself.

Mankind has built computers in a fraction of that time. Even a blind watchmaker can make a pocket watch if you give him long enough.

Anonymous Tue Jun 15 01:38:46 2010 No.1188636 [DELETED]

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Anonymous Tue Jun 15 01:42:57 2010 No.1188664

>>1188606
If your really interested in it, you should buy "This is your brain on music". It's educational, adds a scientific and mathematical element to music, and is one of the best reads I've had in a long while. It even goes into the biological/evolutionary aspects of music. It might be on rhizone, if you're broke.

Also, bumping to keep troll threads of /sci/.

>>	Anonymous Tue Jun 15 01:43:57 2010 No.1188674 >>1188664 I might. Though that might be more up my brother's alley. Also, I assume you mean off.

Anonymous Tue Jun 15 01:45:46 2010 No.1188686 [DELETED]

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Anonymous Tue Jun 15 01:47:46 2010 No.1188695 [DELETED]

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Join us for 18 boards of AWESOME weapons discussion. OPERATORchan is an imageboard totally focused around weapons, militaries and similar topics. Talk about gear, Airsoft, weapons; even survival, food & hunting in an OPERATOR-friendly environment. Visit us today! You have nothing to lose, and a great board to gain!

http://www.operatorchan.org
http://www.chairforce.org
http://www.misunderstoodweapon.org

irc.rizon.net #/k/

See you there!
7466716698

>>	Anonymous Tue Jun 15 01:47:57 2010 No.1188694 okay its time to archive this shit. 4chanarchive.org request interface go!

Anonymous Tue Jun 15 01:48:57 2010 No.1188704

>>1181172
>>1181172
>>1181172
>>1181172
>>1181172
>>1181172
>>1181172
>>1181172
>>1181172
>>1181172

I thought plaque (fat and cholesterol crystallites) built up due to arterial damage.

I was not aware that plaque was the result of shit just floating and getting stuck to the walls, I thought it literally took cell damage to incur the buildup.

Of course, excess LDL and HDL can damage the walls, and so can other dietary factors...

but again, the damage is what causes the plaques to form initially.
also saturated fat is stronger factor in the development of high blood cholesterol than is dietary cholesterol.

>>	Anonymous Tue Jun 15 01:49:57 2010 No.1188705 bumping for chemo.

>>	Anonymous Tue Jun 15 01:50:57 2010 No.1188708 >>1188704 I'm not too sure anymore. I'm pretty sure I'm wrong, considering how many people have bitched about it. >>1188694 Already done bro.

Anonymous Tue Jun 15 01:55:46 2010 No.1188745 [DELETED]

File: 96 KB, 1144x816, 8490356788.jpg [View same] [iqdb] [saucenao] [google]

Do you guys like OPERATORS? How about OPERATORS OPERATING OPERATIONALLY? Well, good news, because there's a site that's dedicated to OPERATORS like you --OPERATORchan!

Join us for 18 boards of AWESOME weapons discussion. OPERATORchan is an imageboard totally focused around weapons, militaries and similar topics. Talk about gear, Airsoft, weapons; even survival, food & hunting in an OPERATOR-friendly environment. Visit us today! You have nothing to lose, and a great board to gain!

http://www.operatorchan.org
http://www.chairforce.org
http://www.misunderstoodweapon.org

irc.rizon.net #/k/

See you there!
3021144261

Anonymous Tue Jun 15 02:02:46 2010 No.1188799 [DELETED]

File: 28 KB, 449x308, 3970234390.jpg [View same] [iqdb] [saucenao] [google]

Do you guys like OPERATORS? How about OPERATORS OPERATING OPERATIONALLY? Well, good news, because there's a site that's dedicated to OPERATORS like you --OPERATORchan!

Join us for 18 boards of AWESOME weapons discussion. OPERATORchan is an imageboard totally focused around weapons, militaries and similar topics. Talk about gear, Airsoft, weapons; even survival, food & hunting in an OPERATOR-friendly environment. Visit us today! You have nothing to lose, and a great board to gain!

http://www.operatorchan.org
http://www.chairforce.org
http://www.misunderstoodweapon.org

irc.rizon.net #/k/

See you there!
412778648

>>	Anonymous Tue Jun 15 02:05:57 2010 No.1188815 I salute mods for getting on this spam.

>>	Anonymous Tue Jun 15 02:10:57 2010 No.1188837 Bump

>>	Anonymous Tue Jun 15 02:27:57 2010 No.1188919 i approve, yet do not have anything to contribute ask a trumpet player anything. or anything about heroin

>>	Anonymous Tue Jun 15 03:19:57 2010 No.1189219 >>1188919 how's it feel, man?

Anonymous Tue Jun 15 03:40:57 2010 No.1189292

>>1188536

Not same poster, but I figured I'd pick in since I've got a Genetics exam tomorrow and it can't hurt to write some stuff down.

Unfortunately, though, eukaryotes have no operons. In fact, the eukaryotic genome, compared to the bacterial genome, is a gigantic fucking mess. It doesn't seem to be very well-organized, and its coding sequences are ridiculously scarce(1.5%). Furthermore, there's immense variation even amongst the coding sequences. Now, I know you guys know what introns and exons are. But did you know how seemingly random these things are distributed? Take the dystrophin gene, for example. It's 2.4 megabases in length. That's about 5% of coding sequences, which is gigantic. Of course, not all of this stuff is expressed. The introns are spliced out.

And then I'm not even talking about the enormous stretches of seemingly useless DNA between genes. This all begs the question: Why? Why go through all the trouble to encode all that junk? Now, I'm not saying introns are useless, they have a few very important functions. For starters, alternative splicing(excising a few exons along with introns) results in a diversity in gene products encoded by a single gene. They're also believed to be involved in RNA interference due to transcription into microRNA's.

Anonymous Tue Jun 15 03:40:57 2010 No.1189295

>>1189292

Let's talk non-coding sequences. The Alu sequence, for example. It's a type of repetitive DNA called a SINE, or short interspersed nuclear element, found about once every 3000 bases. What's particularly interesting about it, though, is that it's found mainly in or near coding sequences. This is partly because it just likes to integrate there, unlike its big brother, the Line1 segment, who prefers AT-rich regions. However, it's also been proven that it's expressed under stress. Those non-protein-coding SINE sequences are expressed, and they go ahead and bind to Protein Kinase R, or RNA-dependend protein kinase, which inhibits protein synthesis. So, basically, those elements help the cell to not die when shit hits the fan.

Anonymous Tue Jun 15 03:48:57 2010 No.1189320

>>1189295

Furthermore, those non-coding elements have a bunch of other cool functions, a lot of which can be used in genetic engeneering. Take the Cre-LoxP system, for example. So you have one mouse. You take one of its genes, and you ad a few tiny segments on either side(LoxP sequences), so it's flanked by those sequences. Then you make it reproduce with a mouse that has Cre(Causes REcombination) expression so that the offspring expresses both Cre and has a LoxP-flanked gene. Now, what Cre does is, it excises the sequence flanked by two same-orientation loxP sequences. Here's where it gets interesting.

You can just buy mice that express Cre only in a specific organ, cell type, or at a specific growth stage. So, cross your mouse with the right mouse, and you can make it just not have a type of cell. Say you knock out RNA Polymerase 2, but your Cre is only expressed in, say, the pancreas due to an insulin-specific promoter, your mouse has diabeetus.

>>	Anonymous Tue Jun 15 03:54:57 2010 No.1189339 The reason eukaryotic genomes look like such a mess might be because they tend to be far more complex. But it could also be a simple consequence of the system that's evolved.

>>	Anonymous Tue Jun 15 04:05:57 2010 No.1189382 >>1189339 It's both, actually. They're so complex because there's been tons of duplications, so there's bound to have been some non-productive ones in there that haven't yet been counterselected against.

>>	Anonymous Tue Jun 15 07:10:57 2010 No.1190254 OP here, this thread is over 24 hours old.

/sci//m//e//d//f//a//g/ Tue Jun 15 07:14:57 2010 No.1190294

>>1190254
And deserves every minute of it.

I will most likely make some image macros containing info in this thread but in a curt, understandable style, for future reference and posting in info dumps. Will invite other /sci/entists to help me when I get around to it.

>>	Anonymous Tue Jun 15 07:22:57 2010 No.1190361 >>1190294 >>1190294 >curt, understandable style Do want. Some of this stuff is written in a pretty patronising tone tbh.

>>	Anonymous Tue Jun 15 07:23:57 2010 No.1190370 >>1190294 Cool. Each one, in true /sci/ style, should start with "FUCKING X HOW DOES IT/THEY WORK"

Anonymous Tue Jun 15 09:08:57 2010 No.1190944

Let's talk real fast about pseudogenes.

For the interest of this post, let's define a gene as a sequence of DNA that codes for a protein.

Keep in mind that a lof of your genome's actually just junk sequences - random ATCG that means gibberish in terms of DNA 'language'. If you remember the earlier posts on codons and how they code for proteins though, all 64 combinations of NNN (where N = any base) can code for amino acids! What differentiates 'gene' from 'junk'?

Promoters are specific DNA sequences that are placed strategically around the genome that tell cell machinery 'hey, there's a gene here'. Genomic junk, however, have no promoters. Pseudogenes, on the other hand, were once genes that got their promoters fucked up due to random mutations. Additionally, over time the gene sequence degenerates and starts looking more and more like genomic junk. Think about it like playing Scrabble in a car (the non travel-friendly kind). Over time, the nice words on the board get jiggled and vibrated until they become a mess. If you squint you can still see some of the words, but it's still a mess.

Anonymous Tue Jun 15 09:42:57 2010 No.1191095

Just briefly:

Prions. These little fuckers are, in my eyes, evidence for the absence of a loving God. Know why? Let's talk proteins.

Structural proteins in the body don't just float around as chains of DNA, the space taken up would be comparably enormous and all of their individual function would be rendered inert. What they do is conform to different shapes, which then undergo further structural changes to finish folding. Primary, secondary, tertiary and quarternary structure.
Primary - the amino acid strand, straight up DNA
Secondary - Alpha helices or Beta sheets.
I won't go into the other two yet, because there's a lot there i dont need to talk about. Point being, A is A. If it wasn't thing's wouldn't work, it'd be like trying to replace your car wheels with pencil erasers. Cont...

Anonymous Tue Jun 15 09:50:57 2010 No.1191138

>>1191095
Jumping quickly to a more full-body view, these alpha and beta arrangements are the basis for every cell protein and function throughout the body, including the brain and spinal neurones. Now, prions are just little fragments of protein that go undegraded. But when one of them gets in contact with alpha helices in your brain, they manage to take this carefully crafted and entirely essential helix and dick over the folding just so, turning it into a Beta sheet. This converted beta sheet then does the same to every other alpha helix in contact, and so on and so on. It's like all your brain cells suddenly have syphillis and it's the 60s. Cont...

Anonymous Tue Jun 15 09:52:57 2010 No.1191143

>>1191138
So, this spreads through your brain and spine, driving you mad day by day. Memory loss, hallucinations, unbalanced, no control of your limbs, fucking psycho son. CJD. Mad Cow Disease. These are prion disease. Hell, a tribe in Africa used to be endemic for the prion disease Kuru as, when they're elders went mad and died, it was tradition to eat their brains. And all the prions therein.

Yep, you get prions by eating them, thus the crackdown on Mad Cow beef through Britain. But that's not the only way. You can pick them up by contact, or they can just happen. At any time.

That's right, there is nothing stopping you from sporadicly going off your bloody nut, and no-one will know until they get a brain biopsy. At which point you'll probably get quarantined.

Enjoy living with that hanging over you forever more.

>>	Anonymous Tue Jun 15 09:55:57 2010 No.1191150 >>1191143 OP here. That fucking sucks. We need someone else to post info, that way it's not such a depressing note.

>>	Anonymous Tue Jun 15 09:55:57 2010 No.1191155 >>1191143 This post is absolutely beautiful and fantastic, but I just shat an entire brick FACTORY at the end. Excellent points about proteins though.

Anonymous Tue Jun 15 09:56:57 2010 No.1191157

>>1191143
not this poster, but prions cannot be rendered safe or incommunicable. there are no known sterilization procedures that we have that will render prions inactive. Surgical instruments are reused after sterilization but prions are unaffected by this process.

Anonymous Tue Jun 15 10:03:57 2010 No.1191179

Alright, more horrifying shit from a mathfag:

One day, some people realized that they had no idea that anything they'd done was actually completely proven- they'd made some pretty simple assumptions in the beginning, like 1 + 1 = 2, or you can always draw a circle with given center and radius. So they decided to try and prove those, too. This was called the Principia Mathematica, and it was a try at proving all of math from a few even more basic axioms.

The basic idea was to prove that from a few basic statements a statement can be proven if and only if it is true.

Cont...

Anonymous Tue Jun 15 10:04:57 2010 No.1191183

Enter Kurt Godel, late 1930's. He looks over what they're trying to do and realizes something.

No matter how they phrase the logical system they're working in, Godel can always write a true statement that cannot be proven in the system, basically:
"This statement cannot be proven in the system."

Russell and Whitehead (the guys writing PM) took one look and shat bricks, and found the alternative to be even worse- the only logical systems that you can't write this in are ones that you can't prove all true statements in.

That's right- no matter what you do, you will never be able to prove all true statements in a logical system without having some false ones accidentally proven as well.

Anonymous Tue Jun 15 10:10:57 2010 No.1191212

Basic computer assembly:

First you need a case to contain and mount the parts to. You need to ensure that the motherboard will not only fit within the case, but that the screw holes will also line up! So you put the screw studs into the case and then lay down your motherboard and screw the screws into the screw studs through the motherboard.
Now the CPU is probably the most delicate bit of the whole thing. It's this little square metal chip about 1" by 1", and on the underside is about 100 little pins. If ONE of those pins gets bent you're FUCKED. So you gotta be fucking CAREFUL with it. You flip up the little bar lever on the motherboard, carefully insert it (you'll know the right way because there will be a small gap in the pins in a corner corresponding with a gap in the motherboard), and push down the lever to lock it in place. Slap some thermal paste down on top of that and put the heatsink on.

Time to put in the power supply, but don't hook anything up yet. Just shove the cables somewhere where they won't be in the way. Take the box, put it into what is usually the top back side of the case. Make sure it's facing up the right way, line up the holes and screw the screws.

Now you get your various drives into the case. Disc drives at the top, indicators below that, and then the hard drive(s) below that. There should be several metal slots these drives fit into. Just slide em in there and line up the holes. Make sure the drives are facing up the right way, and screw in the screws to secure them in place. Connect the cables to the motherboard, there should only be one or two places that will fit the plugs, so as long as you're plugging into those plugs you'll be fine. If you've got multiple hard drives, you'll need to connect them to each other, and you'll need a special cable for that.

Anonymous Tue Jun 15 10:11:57 2010 No.1191217

>>1191212
Now slam in the RAM to the appropriate slots. You'll need to open up the little plastic clips, line up the gaps, and then push down hard. Not so hard that you break the RAM sticks dipshit, but the clips will need to engage on their own so you need to push down until they do. Your thumbs will probably hurt afterwards.

Ok now is a good time to put in the fans. Just line up the fans with the holes and screw em in. Worry about the cables a little later

Time for a game of cards: we put in the video card, the internet card, the sound card (if it's not integrated to the motherboard for some reason), and your USB slots (if applicable). It's pretty much just like the RAM, just line up the gaps and plug em in. Now the unique thing about these is that they probably have this little metal thing sticking up out of one side. You have to screw those into the back of the case where they line up so they don't jiggle the fuck around when you try to plug something into em.

Now we plug everything into everything else. Power supply goes to just about everything. If you don't know where a plug goes, read the fucking manual. It's different for just about every type of equipment out there, so you really do need to read the fucking manual. So I would advise you read the fucking manual. READ THE FUCKING MANUAL.

I SAID READ THE GODDAMN FUCKING MANUAL YOU STUPID MONKEY PIECE OF SHIT- ok good now you know where they plug in. So follow those instructions. You're also going to be plugging in the ON/OFF and RESET buttons from the front panel and any other kind of display or LED bullshit you put up in there. Fans usually plug directly into the power supply.

Anonymous Tue Jun 15 10:12:57 2010 No.1191225

>>1191217
Ok now stand bag and it looks like a goddamn mess. If your case has now see through parts, just make sure nothing isn't going to catch fire and close her up. If it does have a see through side, you gotta make that shit look organized. Bundle up the cables - without unplugging them you dipshit - and wrap them together with twist-ties. Preferably ones that aren't going to melt or catch fire. It gets upwards of 100 degrees in there, computers generate about as much heat as a person y'know.

Ok, now start it up. No, wait plug it in first you idiot. NOW start it up. WHAT DO YOU MEAN YOU DIDN'T PLUG IN THE FUCKING KEYBOARD?! YES YOU PLUG THAT IN - NO NOT NOW TURN IT OFF FIRST OR YOU'LL SHORT CIRCUIT THE THING. YES THE MOUSE TOO. YEAH, THE MONITOR WOULD PROBABLY BE A GOOD IDEA AS WELL. Ok, now that you have everything you need plugged in bust out your Windows disc and -

No you can't do this with a mac, it's a fucking PC. Well the difference is that you can't buy different parts for a mac, it's all integrated. Because macs are for people who don't know how to do this kind of shit, that's why. No, that doesn't mean Linux is better- you know what just shut up and put in the XP disc before I shove it down your throat. Follow the herp-derp instructions and you're done. Just set up your computer the way you want it.

Anonymous Tue Jun 15 10:13:57 2010 No.1191233

>>1191225
Oh, of course you want all your old files off of your previous computer. Of course it's corrupted and you can't burn it all into a CD or flash drive, that would just be too easy. Ok, well you're gonna have to slave the old drive onto the new one and pray your files are retrievable. You don't really NEED special software for this but it helps. Yes, this does indeed mean you're going to need to open the computer back up, how the fuck did you think you were going to get the files on there? "Wirelessly"?! Ok, smartass, just plug that thing into that thing and fire her back up. Follow the instructions included with the software and you'll be good to go.

Now leave me the fuck alone, I've got to get back to World of Warcraft.

Anonymous Tue Jun 15 10:13:57 2010 No.1191240

>>1191157
Oh, yeah, this too. How fucked are you now?

I only wish this were the worst stuff i've picked up in my biology studies. If you want some superbly brickshitting biology, engineering and all around hell, i recommend you check out "Everything Is Going to Kill Everyone" by Robert Brockway. He writes for cracked.com, so you peruse his periodicals there. It's a nice little book of doom.

This is unrelated, but keeps the horror rolling. It's even narrated by David Attenborough: http://www.youtube.com/watch?v=XuKjBIBBAL8

>>	Anonymous Tue Jun 15 10:35:57 2010 No.1191376 Don't you die on me now!

>>	Anonymous Tue Jun 15 10:42:57 2010 No.1191434 >>1191376 OP here. Don't worry, it will be archived. Try sending in a request and see for yourself. This is my last post here, I must go now. Thank you all for a wonderful thread.

>>	Anonymous Tue Jun 15 12:51:57 2010 No.1192097 To sum it up - Prions are like the zombies of the protein world.

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