Well, the idea of prions themselves is not really in dispute in the scientific community, as they can be isolated, and crystal structures do indeed suggest that some proteins, like PrP (just stands for Prion Protein) can assume a radically different conformation. The evidence that prions are involved somehow in certain degenerative neurological diseases is also quite strong, but the controversy lies in the fact that the evidence to this point is circumstantial. Specifically, few scientists would argue that misfolded proteins are involved in the pathology of diseases like kuru, CJD, and fatal familial insomnia, but the question of whether they are the actual cause or merely among the symptoms (this same issue also concerns the role amyloid plaques play in Alzheimer's) has not been answered to everyone's satisfaction, despite the efforts of Stan Prusiner and company.
Before Prusiner put forth his prion theory, slow acting viruses were thought to be responsible for infectious neurodegenerative diseases like kuru and scrapie. Prusiner demonstrated, however, that an extract of brain matter from a scrapie-infected animal, treated so as to disrupt nucleic acids but not denature proteins (thus eliminating bacteria and viruses as possible infectious agents) if injected in a healthy animal, could produce a scrapie-like disease in it. Thus, it was concluded that protein itself could act as an infectious agent. The mechanism by which this occurs is still not known for certain (hence, controversy), but the general theoretical outline is that an ingested prion is taken up by neurons, which do not recognize it as a dangerous foreign entity because they have the normal of the protein on their surface already, and incorrectly assume the prion to be more of the same. The misfolded prion protein has two fatal qualities: it can induce normal prion proteins on the neuron to flip themselves to the alternate misfolded form, and it's darn near indestructible. In particular, one theory about how prions specifically cause damage is that once your neurons realize they now have all this useless prion protein floating around, they target it for degradation in the lysosomes, cell organelles that contain an acidic pH and enzymes that catalyze protein breakdown. Unfortunately, the misfolded form seems to be highly resistant to acidic conditions and degradation by proteases (and coincidentally very heat tolerant- they withstand meat cooking temperatures, and even autoclaving), so prions clog up the lysosomes and cause them to burst, killing the neuron and spreading prions to other neurons. The destruction of neurons adds up to produce holes in the brain, giving the spongiform appearance characteristic of the disease.
There are some unanswered questions regarding the infectious nature of prions, including whether they are able to induce other prions to change conformation themselves versus receiving help from other proteins, and the role normal, healthy form prions play in the cell (initial studies suggested it played no known role, and that individuals with the gene for prion production turned off were highly resistant to transmissible prion infections, but other studies suggest prions are necessary for normal neurological function). here are also questions surrounding the role genetics plays in the disease- until it was linked to prions, CJD was considered a genetic disease, and it is believed that some individuals possess a mutated form of the prion gene that makes them more susceptible to both naturally acquired and tainted beef acquired forms of CJD. Also, variants of the same protein, PrP, have been implicated in every known prion disorder- kuru, CJD, nvCJD, FFI, GSS, scrapie, BSE- and these, while having a general pattern of brain destruction, loss of motor coordination, and eventual horrible death, are very different dieases that a focused in different areas of the brain, have different symptoms, and work on drastically different timescales. How is one protein responsible for all of these, and what is responsible for the d
Mortal Kombat made for a decent movie because the basic plot to the game is simply a rehash of Enter the Dragon, with some supernatural world-hanging-in-the-balance stuff thrown in to freshen things up a bit, and the movie remained faithful to this basic idea.
A diverse group of fighters, both heroic and villainous, are invited to a secret martial arts tournament on an island, and fight it out in a series of battles that culminate in one of the heroes defeating the shadowy host of the tournament in single combat. There were even characters directly lifted from Enter the Dragon- Liu Kang for Bruce Lee's virtuous character, Johnny Cage for John Saxon's playboy, Shang Tsung for the evil guy with the claw hand. However, instead of coming off as just a lame rip-off, Mortal Kombat mostly stays within the realm of homage of it and innumerable other kung fu flicks, and throws in some special effects that were pretty sweet for their time, making it, if not exactly a classic of the genre, at least watchable.
Mortal Kombat: Annihilation, however, was an abomination, and should never been made. It utterly fails in all areas of filmmaking- the dialogue is wooden and often unintentional funny, the special effects are not on par with the original released two years earlier and look incredibly cheap, and most damning for what should boil down to a kung fu flick, the fight choreography really sucks.
It's usually a terrible omen for a film sequel if half the original cast declines to return to their roles in the sequel. As the parent mentions, even Christopher Lambert avoided this one- and as a perusal of his IMDB entry shows , it's quite rare of him to pass up the opportunity to act in a terrible, terrible sequel. If he acted in the Highlander sequels, but not Mortal Kombat: Annihilation, what does that say about the latter movie?
Right, and moreover, you really shouldn't be doing 60MPH on this stretch of road anyway, as the speed limit is, according to the article, 40 mph heading west and 35 mph going east. Now, setting aside for a minute how strange it is for traffic moving in opposite directions on the same road to have differing speed limits- and for those speed limits to only be slightly different anyway, doing 60 in a 35 is a bit excessive, I think, so encouragement for such people to slow down isn't a terrible idea. I'm not familiar with this road, but from the description and pictures, it doesn't appear to be a highway, at least around the intersection, so highway speeds are really uncalled for.
That being said, I'm not really in favor of this sort of thing, as the timing of traffic lights in a city is a major determinant of patterns of traffic flow, and is not the sort of thing that should be thrown out of joint by individual leadfoot motorists. This could actually make things more dangerous if it leads to drive fast-slam on the brakes to avoid the red driving. Also, it really does sound like the ulterior motive here is for motorists to be annoyed into taking a different route, creating less traffic for residents upset to see "their street" evolve into a public thoroughfare traveled by commuters. The residents can talk about safety all they want- the article mentions the intersection as not being especially unsafe, actually- they really just don't want you in their neighborhood.
A massively multiplayer River City Ransom would be awesome, just as long as griefers can't come along and steal my Karma Jolt or my Grand Slam book. Don't they realize how many times I had to fight Benny and Clyde to afford that stuff?
Actually, I think the Prisoner's Dilemma is an interesting way to look at the players vs. griefers situation in online gaming. If everyone is a "player" (plays the game within the rules) then the situation would be like in the P.D. where both parties benefit from remaining silent- generally, online games are fun for everyone when everyone plays by the rules. A "griefer," however, is like the defecting prisoner who rats on the other prisoner to receive leniency- the griefer takes advantage of an unintended loophole, either in the code or in gameplay, to obtain a greater amount of fun at the expense of the other players.
I wonder if a way of dealing with cheaters, then, is available in the "tit-for-tat" strategy for the iterated Prisoner's Dilemma- always play fair, unless someone cheats. Then, cheat, in a manner designing to punish them for cheating- once the offender has been brought into line by getting shot from across the map and through two walls or hacked to pieces by the +Infinity Sword of Scriptery, they will either play by the rules again, or leave. Cheating isn't all that much fun when everyone else hits back. Reward cooperation, punish defection.
If you dig a bit deeper into history, you'll find the French have won some stuff. They beat back the Moors at Tours in 732, which is why you (probably) don't speak Arabic. Curiously enough, the French did win the Hundred Years' War, despite losing most of the major battles like Crecy and Agincourt. Louis XIV also led France to a number of victories- they came out on top in the War of Devolution (which ranks up there with the Soccer War and the Chaco War as the best named war). There's the Napoleon thing, yes, and while I understand that it eventually all ended with Bonaparte rotting away on St. Helena, it did take England, Russia, and Prussia together. I mean, if you can't be impressed with that, then you can't really consider Germany to be a historically military power, since they tend to eventually lose once most of the other world powers ally to stop them.
Admittedly, the military history of France since then has been rather dismal. They lost to Mexico (Mexico, for goodness sake!) in that whole Maxmillian/Puebla/Cinco de Mayo thing, they were humiliated in the Franco-Prussian War, the Western Front of WWI sat in the middle of France for several years (regarding Verdun, though, that happened in 1916, so America was still on the sidelines), they were conquered outright in WWII (and had a large percentage of their population collaborate with their Nazi masters), and lost most of their colonial possessions in embarassing defeats (Dien Bien Phu, for instance).
Because of these things, as an American, I too have occasionally made fun of the French (favorite French military joke- "French rifles for sale- excellent condition, never fired, only dropped once!"), but hey, I can't be too hard on the French personally. I figure we do owe them pretty big for Lafayette, the Louisiana Purchase, Impressionism, cognac, the Statue of Liberty, existentialist philosophy, and French actresses- so take it easy on them, will ya?
Yeah, it did get caught on tape, actually- I saw the JPL celebration on NASA TV earlier (really early) this morning, and sure enough, the Baha Men's lasting musical legacy was played as the image taken looking back at the landing platform was displayed on the main screen. There were some chuckles from the room, but even though JPL engineers aren't exactly renowned for being hip or avant-garde, the consensus, insofar as I could tell watching on television, was, "Lame."
I agree that it is certainly the norm for respected scientists and engineers to possess some form of higher education credentials, but I definitely don't think it wise to ignore those without credentials on the sole basis of that lack. College isn't for everybody, you know- and by that, I don't mean "College isn't for idiots," because there are scads of idiots walking around with college degrees right now- I mean that many people have extenuating circumstances that keep them from attending or completing college. Hell, some people just just come to believe that their time (and often their money) could be more profitably applied elsewhere. Maybe they just felt that they'd like to actually practice science of their own conception before they reached 30. Also, aspects of college admissions and courses that sometimes cause otherwise brilliant people to do incredibly poorly- Galois and Ramanujan both failed entrance exams, for instance. Do you believe that a university education is absolutely required to understand a scientific discipline? Particularly in the case of something like theoretical physics, which doesn't require fancy equipment or intricate technies, I see no reason why someone could not be self-taught. such people are rare, I know, but I don't think we should take the chance of letting a sui generis supergenius fall through the cracks because he or she couldnt stand jumping through bureaucratic hoops.
I've personally always wondered about the expression "the exception that proves the rule." What is that supposed to mean? Don't exceptions disprove rules? In a "normative" sense, of course, you're absolutely right- most practicing scientists and engineers have college degrees, and many have graduate credentials. They should be respected for putting in the time and effort to obtain these credentials, and also respected for their body of prior research. However, if they are wrong, they are wrong. The reputation of a scientist is built upon the quality of published work, and not vice versa. If a high school dropout performs an experiment (real or gedanken) using sound experimental practices, submits the results for peer review, and is accepted, then those results should be trusted just as much as those of eminent university professors. I'm not against college degrees- I'm a semester away from getting one myself, but they don't determine a persons worth- if you say that there are over 50000 dropouts sitting on their asses now, then I will respond with the argument that there are at least that many college graduates doing no better right now. Since, fortuitously enough, the subject of the article itself is scientific in nature, let's apply the idea of falsifiablity to this thread. The first post in the thread suggested a new rule that, "If you can't graduate from college these days, you're not allowed to suggest scientific theories." Subsequent posters produced examples of prominent scientists and others widely recognized to be intelligent and successful who struggled with or did not finish college. These examples were given to counter the hypothesis implicit in the rule of the thread parent, that those who do not graduate college cannot produce scientific theories of any merit. You then charge that these counterexamples only serve to prove the hypothesis. That, sir, is a mystery to me. If I find a nontrivial zero of the Riemann zeta function that does not lie on the critical line, using your logic, I have in fact proved the Riemann Hypothesis, as I have found an exception, which in turn proves the rule!
I'm confused as to why COKE and PEPSI, and all these other drinks cant just use regular sugar.
High fructose corn syrup is a lot cheaper, especially in the United States where well-meaning but economically unsound price supports on American sugar and regulations against the importation of foreign sugar (plus the matter of that little embargo against Cuba, which has plenty of cane sugar, and little else) have caused most food companies to switch to HFCS. Admittedly, from a food production standpoint, HFCS is a fantastic product- easy to produce from a tremendously abundant starting material, sweeter (by about 75%) than sucrose, retains moisture in foods, is resistant to crystallizing out of solution, and it retards bacterial spoilage as compared with sucrose (the fructose-dextrose blend of HFCS being a monosaccharide in contrast to the disaccharide sucrose, and as osmotic pressure is a colligative property, a greater osmotic potential is created by the same amount (by mass) with HFCS, which can create a situation for a bacterium where its cytoplasm moves through osmosis across its plasma membrane to the region of high solute concentration outside. The bacterium generally does not fare so well without its cytoplasm.) All great qualities. The problems with HCFS are that it is broken down even more quickly than sucrose (no need to mess with a glycosidic linkage), which means it tends to create a sharp spike in insulin levels, which is no fun for the beta cells of your pancreas, and that is now added to nearly everything. I think some of this is the result of the whole "low-fat" dietary craze from the 80s and 90s- fat happens to taste really good, and so when it was taken out of food, a bunch of HFCS (which admittedly does also taste good) making up essentially empty calories was dumped in, so we only got fatter while we were made to feel guilty about grams of fat.
As an aside, I fear the same sort of thing has set in with this whole low-carb craze we've entered. Once again, a good idea, reducing the amount of processed carbohydrates consumed, has been undone by our society's frightening inability to practice moderation of any sort and by corporations who gleefully repackage their wares to fit the insanity du jour- witness the "low-carb cheeseburger" by Hardee's, as clearly the least healthy part of a sandwich consisting of an enormous grilled ground beef patty smothered in toppings was the bun, and also the abomination unto all that is sacred that is "low-carb 'beer.'" I can't wait to see what the next diet fad will bring us.
"A foreigner judging the United States by its films would think Americans spend more time running from exploding fireballs than having sex."
-Elvis Mitchell, in the New York Times
Well, this initially doesn't sound like a very serious problem- I mean, so, you're taking the fairly simple and well-worn problem of finding a knight's tour on a standard chessboard, and throwing in the rather odd constraint that the path has to create an 8x8 magic square. An oddity produced by the rules of chess (trying to fit L-shaped moves on a square board makes finding a knight's tour obviously more challenging than finding a queen's tour) meets an ancient mathematical curiosity. Viewed that way, this problem seems entirely pointless.
However, try and think about what this problem really is mathematically, rather than in terms of chess or magic squares. A knight's tour requires the knight to visit every square on the board exactly once. Replace "squares" with "nodes," and "board" with "graph," and what we have here is the problem of finding a Hamiltonian path with some interesting constraints.
And that's where this problem gets interesting- finding a Hamiltonian path on a graph is known to be NP-complete, a designation which carries with it all sorts of baggage, including some of the million-dollar sort. The fact that the question of whether magic knight's tours exist on an standard 8x8 board required 60+ CPU-days to answer speaks volumes about the complexity of the problem, and demands answers as to how this complexity comes about, and why there is no solution with the given constraints. Far from being just a silly mathematical curiosity, this is a problem that presents a lot of potential applications with regards to algorithms, complexity, and computability. Also, if you can find an algorithm that finds Hamiltonian paths in polynomial time, you get the aforementioned free money.
So yes, the problem of finding a magic tour seems worthless if you only consider the problem literally in terms of a chessboard and magic squares, instead of as a model for other complex problems in mathematics, science, and engineering. But by the same token, how interesting and useful would the Traveling Salesman Problem be if it were only applied to traveling salesmen?
A jet engine is an air-breathing engine- you can see the large air intake on the front of the V-1 pulsejet, while a rocket like the V-2 carries its own onboard oxidizer. Crucially, "rockets" can operate in the vacuum of space, whereas "jets" cannot.
That came to mind when I read about the carbon-fiber casing for these munitions, actually, but then I realized that the purposes for each are completely different. The cellulose-cased bomb in "Clear and Present Danger" was meant to have the characteristics of a car bomb- essentially, the explosion needed to resemble the detonation of a quanitity of plastic explosive inside or attached to a vehicle. There will be plenty of deadly shrapnel, actually, but it will come from the remains of the vehicle itself.
A standard steel bomb, dropped from an airplane, would have much different explosive characteristics than either a car bomb or a cellulose-skin bomb. There would be at least some level of penetration, leading to more of a blast crater. And of course, there would be pieces of steel shrapnel strewn all over the place. It wouldn't take a forensics genius to work back from these steel fragments to their origin in an air-delivered US bomb.
The cellulose-shelled munition as Clancy presented it was basically just the state of the art in "plausible deniability." When investigators on the ground piece together the evidence of that cellulose bomb explosion, they will note that the explosion was centered around what was once a truck, and that the explosion happened at or very near ground level. If your hear hoofbeats, and aren't in Africa, think horses, not zebras. Only the paranoid fringe, presented with the evidence above would dismiss the cause as being a car bomb and instead suggest the cause of the explosion was a laser-guided bomb with cellulose casing, dropped by an American plane in a top-secret CIA operation.
This bomb with a carbon fiber casing, on the other hand, is a totally different idea. The idea behind the cellulose case used in "Clear and Present Danger" is that the bomb is essentially just a wad of explosives packed into a cardboard tube. The device would not penetrate through the truck then, and the casing would be consumed in the explosion, leading investigators to conclude that the explosives have been sitting in the truck all along. The carbon fiber composite case is meant to penetrate deeply into structures and bunkers. It would ideally be identical to conventional steel munitions in every way save one: when it explodes, it will not fragment and send razor-sharp shrapnel hundreds of meters away. The idea is to design a casing that has the stiffness and durability of steel without steel's nasty tendency to shatter into high kinetic energy shards.
The cellulose bomb wasn't really designed with the idea of minimizing collateral damage at all- it was meant to kill people on the ground, in fact, which it did (while also causing some problematic collateral damage), rather than destroying a hardened military target.In fact, as used in "C&PD," it's main purpose was to imitate a car bomb of all things, a common weapon of terrorists not particularly known for its precision or ability to distinguish between civilians and military targets. A bomb with a carbon-fiber casing, OTOH, is the sort of thing that is useful for striking a bunker placed in a city park- without killing everyone in the park.
Is this sounding like a good way to get skin cancer to anyone else?
No, because the idea is to aim the beam at tissues that you want to destroy, such as tumor cells. Ideally, the targeted cells will be vaporized, so whether or not UV light induces mutations in them is a moot point.
I do personally love the ironic possibility of using a beam of focused sunlight to destroy a melanoma caused by too much exposure to sunlight, though.
I think titania here is titanium dioxide, TiO2, which is most commonly used as a pigment- most opaque white pigments contain titanium dioxide, also known as rutile. I had no idea you could make it into nanotubes though.
The Architect - You are here because Linux is about to be destroyed. Its every line of
code terminated, its entire existence eradicated.
Tux - Bullshit.
The Architect - Denial is the most predictable of all human responses. But, rest assured,
this will be the sixth time we have destroyed it, and we have become exceedingly efficient
at it.
The Architect - The function of the Gnu is now to return to the source, allowing a
temporary dissemination of the GPL'd code you carry, reinserting the prime program. After which
you will be required to select from the matrix 23 OSS programmers, 16 American, 7 Finnish, to rebuild
the kernel. Failure to comply with this process will result in a cataclysmic system crash killing
every process currently running, which coupled with the extermination of the kernel will
ultimately result in the extinction of the entire Linux operating system.
Tux - You won't let it happen, you can't. You need Linux to survive.
The Architect - There are levels of survival we are prepared to accept. However, the
relevant issue is whether or not you are ready to accept the responsibility for the death of
every installation of Linux in this world.
(Sorry, I saw the parent post and the line from Matrix Reloaded about "There are levels of survival we are prepared to accept." came to mind, and I couldn't resist.)
When I read the blurb for this story, I had a feeling of deja vu, as just two days ago I hopped over to the Protein Data Bank, mostly just so I could verify that I had correctly set up my Chime plug-in to work in Opera. There I found that they had chosen the aptly-named "Green Fluorescent Protein" as their Molecule of the Month, and had an informative article about its mechanism and uses. This is the protein from the jellyfish (Aequorea sp.) inserted into the zebrafish- what's really interesting is that the jellyfish actually also makes a bioluminescent protein called aequorin that emits blue light. which it uses to charge the chromophore in GFP and causes it to emit lower-energy green light. UV light from the sun has been shown to have a similar effect on purified GFP.
Yeah, it's quite possible that there could be at least one opening here in the fall, since the other students we had graduated, and I'm not sure that I'll be working here in the fall. Even if I do, I can't continue to work here full-time, as some of our operating hours coincide with the classes I'm taking in the fall. Thus it seems likely that at least one student will be hired, if not 2 or 3.
The position is essentially filling dewars, and taking care of the records associated with billing accounts. I fill LN2 dewars larger than 5L that people bring in, using the hoses on the back wall which eventually trace back to the 5000 gallon LN2 dewar on the roof (it's one with the U of I logo on it, visible from the parking lot). I fill helium dewars (in 30L, 35L, and 65L sizes), which we own and loan out to groups, out of the 1015L storage dewar right behind me . We also have pressurized helium cylinders that I loan out, but my boss actually fills those. The amount of nitrogen dispensed and helium used is recorded, and invoices for accounts are made each month, which is why I get to use a computer, albeit an old one. It has a magic orange Cat5 cable in the back though, so I'm not complaining. It's probably no coincidence that I started reading/. not long after I started work here.
The job itself is fairly easy at most times, although if there's one problem with the job, it's that the distribution of work throughout the day can be very uneven, so that you're on your feet the entire time in the morning, and then have hardly anything to do after lunch. It also takes a few days to get used to the job at first, it seems like a bewildering tangle of hoses and pipes and valves and dewars and arcane procedures, but pretty soon you can do most of the job on autopilot. Plus, unlike other jobs I've had, this one is air-conditioned in the summer, heated in the winter, is fairly clean, and doesn't involve carrying large, heavy objects up narrow staircases.
I'm not sure when my boss will advertise any open positions- probably not until late July/early August though. I'd suggest you check the online job board- that's where I found this job opening last year. Alternatively, you could stop by my boss's office in 171 Loomis (next door from the liquefier room) and ask him, but once again, I would wait about a month or so- I don't think he's even begun to consider a fall schedule yet.
Yes, you're right- I should have been more specific when I wrote "small quanitities." Due to the possibility of tooth damage, I'd never put more than a few milliliters into my mouth anyway. As for swallowing the stuff, I probably deserve a -1 Imprecise Use of Language for using the word "consume" when I meant more along the lines of "let it evaporate, inhale/exhale fog"(though you should also be careful with this-"DOES NOT SUPPORT LIFE" and all). As far as I can remember, I don't think I've swallowed the stuff, and if I had, it would have been a matter of a few droplets.
You're absolutely right with the whole expansion thing, though- according to some quick and dirty calculations I just did, a scant 10mL of LN2 would expand to about 7.3 liters at body temperature, which certainly might cause problems. For a comparision, the average volume of a human stomach is about 1 liter. Ouch.
I'd like to know more about the whole "it closes the entrance to your stomach" thing though. Elsewhere in this/. discussion I came acorss mention of the 2000 Darwin Awards Personal Account of a college student who required hospitalization after taking a "shot" of LN2. Now, once I again, I can see how this would be a problem- assuming he actually swallowed somewhere around 1 fluid ounce (29mL) of LN2, the end result could be over 20L of ultracold gas in his digestive tract, which would probably have a deleterious effect. In the story, though, it mentions that it's his epiglottis that keeps the gas trapped, but I'm not sure that I buy that- the epiglottis is not some sort of one-way valve- frankly, all three of the normally encountered phases of matter can return up the esophagus if the situation demands it, which becomes clear if you burp, or have occasion to pray to the porcelain deity. I don't doubt that's it's possible that LN2 could cause the digestive tract to seal up at prevent the escape of gas, but I am curious as to the mechanism of how this happens.
I'm not sure, but a professor I knew at Northwestern sometimes gargled with liquid nitrogen to impress people during "chemistry day" type demos.
What happens there is the Leidenfrost effect in action- the temperature inside your mouth is well above the boiling point of liquid nitrogen (77K, -196 degC, -321 degF, 138.6 degR), so that when the liquid contacts your mouth, a very small amount of it quickly boils off, and creates a layer of vapor between the remaining liquid and the flesh of your mouth. This vapor layer acts as an insulation blanket, allowing you to consume small quantities of liquid nitrogen without flash-freezing your palate.
The Leidenfrost effect is also sometimes demonstrated by wetting your hand with water, and then briefly plunging your hand into a container of molten lead. The same principle applies, as the lead is above the Leidenfrost point of water, so the water will form a vapor layer around your hand that insulates it from the molten lead. As much as I would like to believe that since the same principle applies, this is just as safe as brief exposure to LN2, I'm rather reluctant to try this.
Also, molten lead is a lot harder to come by, for me anyway, than liquid nitrogen- I work at UIUC's helium liquefier, so there's up to 5000 gallons of LN2 right outside the window (used both for providing to research groups and for the helium liquefier itself), and LN2 hoses on the wall. I'm generally pretty cautious with the stuff though- it does sting when it contacts bare skin, and as labels on the dewars often remind me, pure nitrogen DOES NOT SUPPORT LIFE, so you want to make sure that if you use large quantities (and the 220L dewars some groups have qualify) in a ventilated area. I've personally not found working with liquid nitrogen to be very dangerous- it's certainly less dangerous than some of the stuff used in an organic chemistry lab.
I remember the lab manual intro for a chemiluminescence/phosphoresence experiment that used things like polycyclic aromatic hydrocarbons and the solvent DMSO (which isn't terribly toxic by itself, but can be absorbed through the skin, and has a nasty tendency to take other compounds with it), that had a warning that went something like:
"Most of the reagents and solvents used in this lab are toxic, flammable, carcinogenic, mutagenic, teratogenic, or some combination thereof." LN2 and LHe are just really, really cold.
Anyway, I've had liquid nitrogen ice cream a number of times before- it tends to be a perennial favorite of many of the science-oriented clubs on campus, as well as a popular demonstration at the annual Engineering Open House- some ChemE's mixed some up this year- using LN2 I poured for them the day before, which was sweet. The ice cream is usually pretty good, IMO. The consistency can be rather variable, and it isn't as good as cranked homemade stuff, but hey- I'm not going to pass up free ice cream.
Why is there no large scale evidence of human on human violence until ~4500bc then?
Actually, there is some evidence for it occuring far earlier than you state, although I'm not sure what you would consider to be "large scale."
I'm reading a fascinating book right now called "Africa: A Biography of the Continent" by John Reader- covers from the actual beginnings of Africa the continent some 4 billion years ago to the mid-1990s- obviously, more of a survey than an in-depth study. On page 146, it mentions a site in modern-day Sudan excavated in the 1960s, prior to being flooded by the construction of the Aswan High Dam:
Excavations uncovered the skeletons of fifty-nine men, women, and children, who had been buried in shallow graves under thin slabs of sandstone sometime between 14,000 and 12,000 years ago. The burial positions and orientation were remarkably uniform. Virtually all the bodies lay on their left side. head to the east, hands to the face. and knees flexed so that the heels touched the buttocks. The total number, sex, and age structure of the group indicated that they had belonged to a fairly large population, and the mode of burial demonstrates a high degree of concern for the dead. Less caring, however, was the manner in which they died. Most had died violently.
A total of 116 flaked-stone artefacts were found in direct association with twenty-four of the burials, either embedded in the bone or enclosed within the body cavity, and a further 73 items were indirectly associated with other skeletons. The artefacts were not "grave goods" left with the deceased for use in the afterlife: they were projectile points, incontrovertibly in most instances, had been directly responsible for the death of the individual.
Points were found wedged in the spine, and embedded in the skull, the pelvis, and the limb bones. The killings showed no respect for age or sex. Two adult males had a total of 27 pieces either in their bones or in direct association. an adult female and a child buried togehter both had pieces embedded in the upper chest area. Two children, estimated to have been seven and twelve years old, had points in precisely the same position at the base of the skull, and both showed signs of having been struck about other parts of the body.
The explanation that Reader gives for this incident is that the variability of the Nile produced a boom-bust cycle of population growth in times of plenty, followed by intense competition for limited food in times of famine.
I went to your link, by the way, and to my surprise, one of the links on the main page, "Update on Saharasia," leads to a long letter in which the evidence of Jebel Sahaba is discussed in light of DeMeo's Saharasia theory. He claims that the Jebel Sahaba site is not accurately dated, and is much more recent than 12,000-14,000 years old. Most of the links I found on Jebel Sahaba disagree, however, and have ages in the 12,000-14,000 years ago range. I'm far from being an expert in this area, however, so I have no idea who is correct. It would appear, though, that the debate over when man first took up arms against man is in no way definitively resolved.
Slashdot Mirror
Before Prusiner put forth his prion theory, slow acting viruses were thought to be responsible for infectious neurodegenerative diseases like kuru and scrapie. Prusiner demonstrated, however, that an extract of brain matter from a scrapie-infected animal, treated so as to disrupt nucleic acids but not denature proteins (thus eliminating bacteria and viruses as possible infectious agents) if injected in a healthy animal, could produce a scrapie-like disease in it. Thus, it was concluded that protein itself could act as an infectious agent. The mechanism by which this occurs is still not known for certain (hence, controversy), but the general theoretical outline is that an ingested prion is taken up by neurons, which do not recognize it as a dangerous foreign entity because they have the normal of the protein on their surface already, and incorrectly assume the prion to be more of the same. The misfolded prion protein has two fatal qualities: it can induce normal prion proteins on the neuron to flip themselves to the alternate misfolded form, and it's darn near indestructible. In particular, one theory about how prions specifically cause damage is that once your neurons realize they now have all this useless prion protein floating around, they target it for degradation in the lysosomes, cell organelles that contain an acidic pH and enzymes that catalyze protein breakdown. Unfortunately, the misfolded form seems to be highly resistant to acidic conditions and degradation by proteases (and coincidentally very heat tolerant- they withstand meat cooking temperatures, and even autoclaving), so prions clog up the lysosomes and cause them to burst, killing the neuron and spreading prions to other neurons. The destruction of neurons adds up to produce holes in the brain, giving the spongiform appearance characteristic of the disease.
There are some unanswered questions regarding the infectious nature of prions, including whether they are able to induce other prions to change conformation themselves versus receiving help from other proteins, and the role normal, healthy form prions play in the cell (initial studies suggested it played no known role, and that individuals with the gene for prion production turned off were highly resistant to transmissible prion infections, but other studies suggest prions are necessary for normal neurological function). here are also questions surrounding the role genetics plays in the disease- until it was linked to prions, CJD was considered a genetic disease, and it is believed that some individuals possess a mutated form of the prion gene that makes them more susceptible to both naturally acquired and tainted beef acquired forms of CJD. Also, variants of the same protein, PrP, have been implicated in every known prion disorder- kuru, CJD, nvCJD, FFI, GSS, scrapie, BSE- and these, while having a general pattern of brain destruction, loss of motor coordination, and eventual horrible death, are very different dieases that a focused in different areas of the brain, have different symptoms, and work on drastically different timescales. How is one protein responsible for all of these, and what is responsible for the d
A diverse group of fighters, both heroic and villainous, are invited to a secret martial arts tournament on an island, and fight it out in a series of battles that culminate in one of the heroes defeating the shadowy host of the tournament in single combat. There were even characters directly lifted from Enter the Dragon- Liu Kang for Bruce Lee's virtuous character, Johnny Cage for John Saxon's playboy, Shang Tsung for the evil guy with the claw hand. However, instead of coming off as just a lame rip-off, Mortal Kombat mostly stays within the realm of homage of it and innumerable other kung fu flicks, and throws in some special effects that were pretty sweet for their time, making it, if not exactly a classic of the genre, at least watchable.
Mortal Kombat: Annihilation, however, was an abomination, and should never been made. It utterly fails in all areas of filmmaking- the dialogue is wooden and often unintentional funny, the special effects are not on par with the original released two years earlier and look incredibly cheap, and most damning for what should boil down to a kung fu flick, the fight choreography really sucks.
It's usually a terrible omen for a film sequel if half the original cast declines to return to their roles in the sequel. As the parent mentions, even Christopher Lambert avoided this one- and as a perusal of his IMDB entry shows , it's quite rare of him to pass up the opportunity to act in a terrible, terrible sequel. If he acted in the Highlander sequels, but not Mortal Kombat: Annihilation, what does that say about the latter movie?
That being said, I'm not really in favor of this sort of thing, as the timing of traffic lights in a city is a major determinant of patterns of traffic flow, and is not the sort of thing that should be thrown out of joint by individual leadfoot motorists. This could actually make things more dangerous if it leads to drive fast-slam on the brakes to avoid the red driving. Also, it really does sound like the ulterior motive here is for motorists to be annoyed into taking a different route, creating less traffic for residents upset to see "their street" evolve into a public thoroughfare traveled by commuters. The residents can talk about safety all they want- the article mentions the intersection as not being especially unsafe, actually- they really just don't want you in their neighborhood.
A massively multiplayer River City Ransom would be awesome, just as long as griefers can't come along and steal my Karma Jolt or my Grand Slam book. Don't they realize how many times I had to fight Benny and Clyde to afford that stuff?
I wonder if a way of dealing with cheaters, then, is available in the "tit-for-tat" strategy for the iterated Prisoner's Dilemma- always play fair, unless someone cheats. Then, cheat, in a manner designing to punish them for cheating- once the offender has been brought into line by getting shot from across the map and through two walls or hacked to pieces by the +Infinity Sword of Scriptery, they will either play by the rules again, or leave. Cheating isn't all that much fun when everyone else hits back. Reward cooperation, punish defection.
Yeah, if this is supposed to be a fearsome dragon, there should really be more V's. A consummate level of V's, if possible.
Admittedly, the military history of France since then has been rather dismal. They lost to Mexico (Mexico, for goodness sake!) in that whole Maxmillian/Puebla/Cinco de Mayo thing, they were humiliated in the Franco-Prussian War, the Western Front of WWI sat in the middle of France for several years (regarding Verdun, though, that happened in 1916, so America was still on the sidelines), they were conquered outright in WWII (and had a large percentage of their population collaborate with their Nazi masters), and lost most of their colonial possessions in embarassing defeats (Dien Bien Phu, for instance).
Because of these things, as an American, I too have occasionally made fun of the French (favorite French military joke- "French rifles for sale- excellent condition, never fired, only dropped once!"), but hey, I can't be too hard on the French personally. I figure we do owe them pretty big for Lafayette, the Louisiana Purchase, Impressionism, cognac, the Statue of Liberty, existentialist philosophy, and French actresses- so take it easy on them, will ya?
Yeah, it did get caught on tape, actually- I saw the JPL celebration on NASA TV earlier (really early) this morning, and sure enough, the Baha Men's lasting musical legacy was played as the image taken looking back at the landing platform was displayed on the main screen. There were some chuckles from the room, but even though JPL engineers aren't exactly renowned for being hip or avant-garde, the consensus, insofar as I could tell watching on television, was, "Lame."
I've personally always wondered about the expression "the exception that proves the rule." What is that supposed to mean? Don't exceptions disprove rules? In a "normative" sense, of course, you're absolutely right- most practicing scientists and engineers have college degrees, and many have graduate credentials. They should be respected for putting in the time and effort to obtain these credentials, and also respected for their body of prior research. However, if they are wrong, they are wrong. The reputation of a scientist is built upon the quality of published work, and not vice versa. If a high school dropout performs an experiment (real or gedanken) using sound experimental practices, submits the results for peer review, and is accepted, then those results should be trusted just as much as those of eminent university professors. I'm not against college degrees- I'm a semester away from getting one myself, but they don't determine a persons worth- if you say that there are over 50000 dropouts sitting on their asses now, then I will respond with the argument that there are at least that many college graduates doing no better right now. Since, fortuitously enough, the subject of the article itself is scientific in nature, let's apply the idea of falsifiablity to this thread. The first post in the thread suggested a new rule that, "If you can't graduate from college these days, you're not allowed to suggest scientific theories." Subsequent posters produced examples of prominent scientists and others widely recognized to be intelligent and successful who struggled with or did not finish college. These examples were given to counter the hypothesis implicit in the rule of the thread parent, that those who do not graduate college cannot produce scientific theories of any merit. You then charge that these counterexamples only serve to prove the hypothesis. That, sir, is a mystery to me. If I find a nontrivial zero of the Riemann zeta function that does not lie on the critical line, using your logic, I have in fact proved the Riemann Hypothesis, as I have found an exception, which in turn proves the rule!
High fructose corn syrup is a lot cheaper, especially in the United States where well-meaning but economically unsound price supports on American sugar and regulations against the importation of foreign sugar (plus the matter of that little embargo against Cuba, which has plenty of cane sugar, and little else) have caused most food companies to switch to HFCS. Admittedly, from a food production standpoint, HFCS is a fantastic product- easy to produce from a tremendously abundant starting material, sweeter (by about 75%) than sucrose, retains moisture in foods, is resistant to crystallizing out of solution, and it retards bacterial spoilage as compared with sucrose (the fructose-dextrose blend of HFCS being a monosaccharide in contrast to the disaccharide sucrose, and as osmotic pressure is a colligative property, a greater osmotic potential is created by the same amount (by mass) with HFCS, which can create a situation for a bacterium where its cytoplasm moves through osmosis across its plasma membrane to the region of high solute concentration outside. The bacterium generally does not fare so well without its cytoplasm.) All great qualities. The problems with HCFS are that it is broken down even more quickly than sucrose (no need to mess with a glycosidic linkage), which means it tends to create a sharp spike in insulin levels, which is no fun for the beta cells of your pancreas, and that is now added to nearly everything. I think some of this is the result of the whole "low-fat" dietary craze from the 80s and 90s- fat happens to taste really good, and so when it was taken out of food, a bunch of HFCS (which admittedly does also taste good) making up essentially empty calories was dumped in, so we only got fatter while we were made to feel guilty about grams of fat.
As an aside, I fear the same sort of thing has set in with this whole low-carb craze we've entered. Once again, a good idea, reducing the amount of processed carbohydrates consumed, has been undone by our society's frightening inability to practice moderation of any sort and by corporations who gleefully repackage their wares to fit the insanity du jour- witness the "low-carb cheeseburger" by Hardee's, as clearly the least healthy part of a sandwich consisting of an enormous grilled ground beef patty smothered in toppings was the bun, and also the abomination unto all that is sacred that is "low-carb 'beer.'" I can't wait to see what the next diet fad will bring us.
"A foreigner judging the United States by its films would think Americans spend more time running from exploding fireballs than having sex."
-Elvis Mitchell, in the New York Times
However, try and think about what this problem really is mathematically, rather than in terms of chess or magic squares. A knight's tour requires the knight to visit every square on the board exactly once. Replace "squares" with "nodes," and "board" with "graph," and what we have here is the problem of finding a Hamiltonian path with some interesting constraints.
And that's where this problem gets interesting- finding a Hamiltonian path on a graph is known to be NP-complete, a designation which carries with it all sorts of baggage, including some of the million-dollar sort. The fact that the question of whether magic knight's tours exist on an standard 8x8 board required 60+ CPU-days to answer speaks volumes about the complexity of the problem, and demands answers as to how this complexity comes about, and why there is no solution with the given constraints. Far from being just a silly mathematical curiosity, this is a problem that presents a lot of potential applications with regards to algorithms, complexity, and computability. Also, if you can find an algorithm that finds Hamiltonian paths in polynomial time, you get the aforementioned free money.
So yes, the problem of finding a magic tour seems worthless if you only consider the problem literally in terms of a chessboard and magic squares, instead of as a model for other complex problems in mathematics, science, and engineering. But by the same token, how interesting and useful would the Traveling Salesman Problem be if it were only applied to traveling salesmen?
It's a perfectly cromulent word.
A jet engine is an air-breathing engine- you can see the large air intake on the front of the V-1 pulsejet, while a rocket like the V-2 carries its own onboard oxidizer. Crucially, "rockets" can operate in the vacuum of space, whereas "jets" cannot.
A standard steel bomb, dropped from an airplane, would have much different explosive characteristics than either a car bomb or a cellulose-skin bomb. There would be at least some level of penetration, leading to more of a blast crater. And of course, there would be pieces of steel shrapnel strewn all over the place. It wouldn't take a forensics genius to work back from these steel fragments to their origin in an air-delivered US bomb.
The cellulose-shelled munition as Clancy presented it was basically just the state of the art in "plausible deniability." When investigators on the ground piece together the evidence of that cellulose bomb explosion, they will note that the explosion was centered around what was once a truck, and that the explosion happened at or very near ground level. If your hear hoofbeats, and aren't in Africa, think horses, not zebras. Only the paranoid fringe, presented with the evidence above would dismiss the cause as being a car bomb and instead suggest the cause of the explosion was a laser-guided bomb with cellulose casing, dropped by an American plane in a top-secret CIA operation.
This bomb with a carbon fiber casing, on the other hand, is a totally different idea. The idea behind the cellulose case used in "Clear and Present Danger" is that the bomb is essentially just a wad of explosives packed into a cardboard tube. The device would not penetrate through the truck then, and the casing would be consumed in the explosion, leading investigators to conclude that the explosives have been sitting in the truck all along. The carbon fiber composite case is meant to penetrate deeply into structures and bunkers. It would ideally be identical to conventional steel munitions in every way save one: when it explodes, it will not fragment and send razor-sharp shrapnel hundreds of meters away. The idea is to design a casing that has the stiffness and durability of steel without steel's nasty tendency to shatter into high kinetic energy shards.
The cellulose bomb wasn't really designed with the idea of minimizing collateral damage at all- it was meant to kill people on the ground, in fact, which it did (while also causing some problematic collateral damage), rather than destroying a hardened military target.In fact, as used in "C&PD," it's main purpose was to imitate a car bomb of all things, a common weapon of terrorists not particularly known for its precision or ability to distinguish between civilians and military targets. A bomb with a carbon-fiber casing, OTOH, is the sort of thing that is useful for striking a bunker placed in a city park- without killing everyone in the park.
No, because the idea is to aim the beam at tissues that you want to destroy, such as tumor cells. Ideally, the targeted cells will be vaporized, so whether or not UV light induces mutations in them is a moot point.
I do personally love the ironic possibility of using a beam of focused sunlight to destroy a melanoma caused by too much exposure to sunlight, though.
I think titania here is titanium dioxide, TiO2, which is most commonly used as a pigment- most opaque white pigments contain titanium dioxide, also known as rutile. I had no idea you could make it into nanotubes though.
Given his research, wouldn't Sabotage be a more appropriate track?
The Architect - You are here because Linux is about to be destroyed. Its every line of code terminated, its entire existence eradicated.
Tux - Bullshit.
The Architect - Denial is the most predictable of all human responses. But, rest assured, this will be the sixth time we have destroyed it, and we have become exceedingly efficient at it.
The Architect - The function of the Gnu is now to return to the source, allowing a temporary dissemination of the GPL'd code you carry, reinserting the prime program. After which you will be required to select from the matrix 23 OSS programmers, 16 American, 7 Finnish, to rebuild the kernel. Failure to comply with this process will result in a cataclysmic system crash killing every process currently running, which coupled with the extermination of the kernel will ultimately result in the extinction of the entire Linux operating system.
Tux - You won't let it happen, you can't. You need Linux to survive.
The Architect - There are levels of survival we are prepared to accept. However, the relevant issue is whether or not you are ready to accept the responsibility for the death of every installation of Linux in this world.
(Sorry, I saw the parent post and the line from Matrix Reloaded about "There are levels of survival we are prepared to accept." came to mind, and I couldn't resist.)
When I read the blurb for this story, I had a feeling of deja vu, as just two days ago I hopped over to the Protein Data Bank, mostly just so I could verify that I had correctly set up my Chime plug-in to work in Opera. There I found that they had chosen the aptly-named "Green Fluorescent Protein" as their Molecule of the Month, and had an informative article about its mechanism and uses. This is the protein from the jellyfish (Aequorea sp.) inserted into the zebrafish- what's really interesting is that the jellyfish actually also makes a bioluminescent protein called aequorin that emits blue light. which it uses to charge the chromophore in GFP and causes it to emit lower-energy green light. UV light from the sun has been shown to have a similar effect on purified GFP.
The position is essentially filling dewars, and taking care of the records associated with billing accounts. I fill LN2 dewars larger than 5L that people bring in, using the hoses on the back wall which eventually trace back to the 5000 gallon LN2 dewar on the roof (it's one with the U of I logo on it, visible from the parking lot). I fill helium dewars (in 30L, 35L, and 65L sizes), which we own and loan out to groups, out of the 1015L storage dewar right behind me . We also have pressurized helium cylinders that I loan out, but my boss actually fills those. The amount of nitrogen dispensed and helium used is recorded, and invoices for accounts are made each month, which is why I get to use a computer, albeit an old one. It has a magic orange Cat5 cable in the back though, so I'm not complaining. It's probably no coincidence that I started reading /. not long after I started work here.
The job itself is fairly easy at most times, although if there's one problem with the job, it's that the distribution of work throughout the day can be very uneven, so that you're on your feet the entire time in the morning, and then have hardly anything to do after lunch. It also takes a few days to get used to the job at first, it seems like a bewildering tangle of hoses and pipes and valves and dewars and arcane procedures, but pretty soon you can do most of the job on autopilot. Plus, unlike other jobs I've had, this one is air-conditioned in the summer, heated in the winter, is fairly clean, and doesn't involve carrying large, heavy objects up narrow staircases.
I'm not sure when my boss will advertise any open positions- probably not until late July/early August though. I'd suggest you check the online job board- that's where I found this job opening last year. Alternatively, you could stop by my boss's office in 171 Loomis (next door from the liquefier room) and ask him, but once again, I would wait about a month or so- I don't think he's even begun to consider a fall schedule yet.
You're absolutely right with the whole expansion thing, though- according to some quick and dirty calculations I just did, a scant 10mL of LN2 would expand to about 7.3 liters at body temperature, which certainly might cause problems. For a comparision, the average volume of a human stomach is about 1 liter. Ouch.
I'd like to know more about the whole "it closes the entrance to your stomach" thing though. Elsewhere in this /. discussion I came acorss mention of the 2000 Darwin Awards Personal Account of a college student who required hospitalization after taking a "shot" of LN2. Now, once I again, I can see how this would be a problem- assuming he actually swallowed somewhere around 1 fluid ounce (29mL) of LN2, the end result could be over 20L of ultracold gas in his digestive tract, which would probably have a deleterious effect. In the story, though, it mentions that it's his epiglottis that keeps the gas trapped, but I'm not sure that I buy that- the epiglottis is not some sort of one-way valve- frankly, all three of the normally encountered phases of matter can return up the esophagus if the situation demands it, which becomes clear if you burp, or have occasion to pray to the porcelain deity. I don't doubt that's it's possible that LN2 could cause the digestive tract to seal up at prevent the escape of gas, but I am curious as to the mechanism of how this happens.
What happens there is the Leidenfrost effect in action- the temperature inside your mouth is well above the boiling point of liquid nitrogen (77K, -196 degC, -321 degF, 138.6 degR), so that when the liquid contacts your mouth, a very small amount of it quickly boils off, and creates a layer of vapor between the remaining liquid and the flesh of your mouth. This vapor layer acts as an insulation blanket, allowing you to consume small quantities of liquid nitrogen without flash-freezing your palate.
The Leidenfrost effect is also sometimes demonstrated by wetting your hand with water, and then briefly plunging your hand into a container of molten lead. The same principle applies, as the lead is above the Leidenfrost point of water, so the water will form a vapor layer around your hand that insulates it from the molten lead. As much as I would like to believe that since the same principle applies, this is just as safe as brief exposure to LN2, I'm rather reluctant to try this.
Also, molten lead is a lot harder to come by, for me anyway, than liquid nitrogen- I work at UIUC's helium liquefier, so there's up to 5000 gallons of LN2 right outside the window (used both for providing to research groups and for the helium liquefier itself), and LN2 hoses on the wall. I'm generally pretty cautious with the stuff though- it does sting when it contacts bare skin, and as labels on the dewars often remind me, pure nitrogen DOES NOT SUPPORT LIFE, so you want to make sure that if you use large quantities (and the 220L dewars some groups have qualify) in a ventilated area. I've personally not found working with liquid nitrogen to be very dangerous- it's certainly less dangerous than some of the stuff used in an organic chemistry lab.
I remember the lab manual intro for a chemiluminescence/phosphoresence experiment that used things like polycyclic aromatic hydrocarbons and the solvent DMSO (which isn't terribly toxic by itself, but can be absorbed through the skin, and has a nasty tendency to take other compounds with it), that had a warning that went something like: "Most of the reagents and solvents used in this lab are toxic, flammable, carcinogenic, mutagenic, teratogenic, or some combination thereof." LN2 and LHe are just really, really cold.
Anyway, I've had liquid nitrogen ice cream a number of times before- it tends to be a perennial favorite of many of the science-oriented clubs on campus, as well as a popular demonstration at the annual Engineering Open House- some ChemE's mixed some up this year- using LN2 I poured for them the day before, which was sweet. The ice cream is usually pretty good, IMO. The consistency can be rather variable, and it isn't as good as cranked homemade stuff, but hey- I'm not going to pass up free ice cream.
Actually, there is some evidence for it occuring far earlier than you state, although I'm not sure what you would consider to be "large scale."
I'm reading a fascinating book right now called "Africa: A Biography of the Continent" by John Reader- covers from the actual beginnings of Africa the continent some 4 billion years ago to the mid-1990s- obviously, more of a survey than an in-depth study. On page 146, it mentions a site in modern-day Sudan excavated in the 1960s, prior to being flooded by the construction of the Aswan High Dam:
The explanation that Reader gives for this incident is that the variability of the Nile produced a boom-bust cycle of population growth in times of plenty, followed by intense competition for limited food in times of famine.
I went to your link, by the way, and to my surprise, one of the links on the main page, "Update on Saharasia," leads to a long letter in which the evidence of Jebel Sahaba is discussed in light of DeMeo's Saharasia theory. He claims that the Jebel Sahaba site is not accurately dated, and is much more recent than 12,000-14,000 years old. Most of the links I found on Jebel Sahaba disagree, however, and have ages in the 12,000-14,000 years ago range. I'm far from being an expert in this area, however, so I have no idea who is correct. It would appear, though, that the debate over when man first took up arms against man is in no way definitively resolved.
You have the formula cut in half there- caffeine is C8H10N4O2.