mukani:

scienceadded:

futuresoldierketchum:

livetomakeadifference:

0ut-0f-f0cus:

This is off the Bermuda Triangle,  where 16+ ships washed up on a sand bar. The mystery is still unsolved

Actually the mystery of the Bermuda Triangle has been given a scientific explanation: methane vents which have been discovered in that region. 

Methane reduces the density of water, causing ships that would normally float, to instead sink.

Methane, when in gas form, messes with the electrical components of aircraft, causing them to fail and sometimes fall right out of the sky.

Methane also causes the water to turn a ghostly greenish color, and the “ghost ships” reported to be seen are simply green reflections of the ships that scatter the bottom of the triangle.

Fucking science, man.

Actually the cause of the Bermuda Triangle is much more simple than the methane thing: it’s a rather big bit of ocean, which the main shipping lanes pass through. Obviously you’re going to have a lot of shipwrecks there, because there’s a lot of ships passing through.

As we can see from the picture, the sea doesn’t need methane to look green, it does that naturally. Also re: the picture, sandbars by their very nature tend to show up overnight (literally, in some cases), and thus skippers like those of the boats shown above can run aground when their charts say it’s deep water.

Methane bubbling up from underwater ice has been blamed for some disappearances, along with rogue waves, aliens, and God knows what else.

Until I get a cite to a scholarly journal, I’m calling bullshit on “methane messes with electrical systems of aircraft.” There’s no reason it should. The famous disappearance of Flight 19 in the Bermuda Triangle was because the flight leader mistook one of the Bahamas for Key West, adjusted his course back home based on that faulty assumption, and accidentally flew out to sea where they ran out of gas. The search plane sent after them that “mysteriously disappeared” was seen exploding in midair, and the aircraft had a known tendency to sometimes randomly explode in flight.

You beat me to it!

(Source: esestpercipi)

neurosciencestuff:

Stress has long been pegged as the enemy of attention, disrupting focus and doing substantial damage to working memory — the short-term juggling of information that allows us to do all the little things that make us productive.

By watching individual neurons at work, a group of psychologists at the University of Wisconsin-Madison has revealed just how stress can addle the mind, as well as how neurons in the brain’s prefrontal cortex help “remember” information in the first place.

Working memory is short-term and flexible, allowing the brain to hold a large amount of information close at hand to perform complex tasks. Without it, you would have forgotten the first half of this sentence while reading the second half. The prefrontal cortex is vital to working memory.

“In many respects, you’d look pretty normal without a prefrontal cortex,” said Craig Berridge, UW-Madison psychology professor. “You don’t need that part of the brain to hear or talk, to keep long-term memories, or to remember what you did as a child or what you read in the newspaper three days ago.”

But without your prefrontal cortex you’d be unable to stay on task or modulate your emotions well.

“People without a prefrontal cortex are very distractible,” Berridge said. “They’re very impulsive. They can be very argumentative.”

The neurons of the prefrontal cortex help store information for short periods. Like a chalkboard, these neurons can be written with information, erased when that information is no longer needed, and rewritten with something new.

It’s how the neurons maintain access to that short-term information that leaves them vulnerable to stress. David Devilbiss, a scientist working with Berridge and lead author on a study published today in the journal PLOS Computational Biology, applied a new statistical modeling approach to show that rat prefrontal neurons were firing and re-firing to keep recently stored information fresh.

“Even though these neurons communicate on a scale of every thousandth of a second, they know what they did one second to one-and-a-half seconds ago,” Devilbiss said. “But if the neuron doesn’t stimulate itself again within a little more than a second, it’s lost that information.”

Apply some stress — in the researchers’ case, a loud blast of white noise in the presence of rats working on a maze designed to test working memory — and many neurons are distracted from reminding themselves of … what was it we were doing again?

“We’re simultaneously watching dozens of individual neurons firing in the rats’ brains, and under stress those neurons get even more active,” said Devilbiss, whose work was supported by the National Science Foundation and National Institutes of Health. “But what they’re doing is not retaining information important to completing the maze. They’re reacting to other things, less useful things.”

Without the roar of white noise, which has been shown to impair rats in the same way it does monkeys and humans, the maze-runners were reaching their goal about 90 percent of the time. Under stress, the animals completed the test at a 65 percent clip, with many struggling enough to fall to blind chance.

Recordings of the electrical activity of prefrontal cortex neurons in the maze-running rats showed these neurons were unable to hold information key to finding the next chocolate chip reward. Instead, the neurons were frenetic, reacting to distractions such as noises and smells in the room.

The effects of stress-related distraction are well-known and dangerous.

“The literature tells us that stress plays a role in more than half of all workplace accidents, and a lot of people have to work under what we would consider a great deal of stress,” Devilbiss said. “Air traffic controllers need to concentrate and focus with a lot riding on their actions. People in the military have to carry out these thought processes in conditions that would be very distracting, and now we know that this distraction is happening at the level of individual cells in the brain.”

The researchers’ work may suggest new directions for treatment of prefrontal cortex dysfunction.

“Based on drug studies, it had been believed stress simply suppressed prefrontal cortex activity,” Berridge said. “These studies demonstrate that rather than suppressing activity, stress modifies the nature of that activity. Treatments that keep neurons on their self-stimulating task while shutting out distractions may help protect working memory.”

Good sound recordings of real tornadoes are hard to come across for obvious reasons. One remarkable example survives of a tornado in 1974 which hit the town of Xenia, Ohio. It was made by a Mr Brokeshoulder, a dauntless sound-hunter who stayed in his apartment as long as was prudent before setting the mic and recorder down and hurrying to the basement. You then hear what is probably the roof being torn off about three-quarters of the way through.

(Source: soundsurvey.org.uk)

brokencities:

Some storm chasers from Texas used our song Ravi to accompany their footage of a massive supercell near Adrian, Texas.

Pretty awe-inspiring images.  Check it out.

You can download Ravi and all of our creative-commons licensed music for free here.

fuckyeahfluiddynamics:

Everyone knows the familiar plonk of a stone falling into a pond but few realize the complexity of the physics.  When a solid object falls into a pool, a sheet of liquid, the crown splash, is sent upward.  Simultaneously, the object pulls a cavity of air down with it. As the water moves inward, this cavity is pinched, creating an hourglass-like shape reminiscent of the shape of a rocket’s nozzle. As the diameter of that pinched cavity shrinks, the velocity of the upward escaping air increases, resulting in the formation of an air jet moving faster than the speed of sound. This air jet is followed by a slower liquid jet that may rebound to a height higher than then original height of the dropped object. So next time you throw a stone into a pond, enjoy the knowledge that you’ve broken the sound barrier. (Photo credit: D. van der Meer; see also Physics World)

Oxytocin has been described as the hormone of love. This tiny chemical, released from the hypothalamus region of the brain, gives rat mothers the urge to nurse their pups, keeps male prairie voles monogamous and, even more remarkable, makes people trust each other more.

Yes, you knew there had to be a catch. As oxytocin comes into sharper focus, its social radius of action turns out to have definite limits. The love and trust it promotes are not toward the world in general, just toward a person’s in-group. Oxytocin turns out to be the hormone of the clan, not of universal brotherhood. Psychologists trying to specify its role have now concluded it is the agent of ethnocentrism.

A principal author of the new take on oxytocin is Carsten K. W. De Dreu, a psychologist at the University of Amsterdam. Reading the growing literature on the warm and cuddly effects of oxytocin, he decided on evolutionary principles that no one who placed unbounded trust in others could survive. Thus there must be limits on oxytocin’s ability to induce trust, he assumed, and he set out to define them.

In a report published last year in Science, based on experiments in which subjects distributed money, he and colleagues showed that doses of oxytocin made people more likely to favor the in-group at the expense of an out-group. With a new set of experiments in Tuesday’s issue of the Proceedings of the National Academy of Sciences, he has extended his study to ethnic attitudes, using Muslims and Germans as the out-groups for his subjects, Dutch college students.

These nationalities were chosen because of a 2005 poll that showed that 51 percent of Dutch citizens held unfavorable opinions about Muslims, and other surveys that Germans, although seen by the Dutch as less threatening, were nevertheless regarded as “aggressive, arrogant and cold.”

Well-socialized Dutch students might be unlikely to say anything derogatory about other groups. So one set of Dr. De Dreu’s experiments tapped into the unconscious mind by asking subjects simply to press a key when shown a pair of words. One word had either positive or negative connotations. The other was either a common Dutch first name like Peter, or an out-group name, like Markus or Helmut for the Germans, and Ahmad or Youssef for the Muslims.

What is measured is the length of time a subject takes to press a key. If both words have the same emotional value, the subject will press the key more quickly than if the emotional overtones conflict and the mind takes longer to reach a decision. Subjects who had sniffed a dose of oxytocin 40 minutes earlier were significantly more likely to favor the in-group, Dr. De Dreu reported.

In another set of experiments the Dutch students were given standard moral dilemmas in which a choice must be made about whether to help a person onto an overloaded lifeboat, thereby drowning the five already there, or saving five people in the path of a train by throwing a bystander onto the tracks.

In Dr. De Dreu’s experiments, the five people who might be saved were nameless, but the sacrificial victim had either a Dutch or a Muslim name. Subjects who had taken oxytocin were far more likely to sacrifice the Muhammads than the Maartens.

Despite the limitation on oxytocin’s social reach, its effect seems to be achieved more through inducing feelings of loyalty to the in-group than by fomenting hatred of the out-group. The Dutch researchers found some evidence that it enhances negative feelings, but this was not conclusive. “Oxytocin creates intergroup bias primarily because it motivates in-group favoritism and because it motivates out-group derogation,” they write.

Dr. De Dreu plans to investigate whether oxytocin mediates other social behaviors that evolutionary psychologists think evolved in early human groups. Besides loyalty to one’s own group, there would also have been survival advantages in rewarding cooperation and punishing deviants. Oxytocin, if it underlies these behaviors too, would perhaps have helped ancient populations set norms of behavior.

Early religions were also involved in establishing group cohesion and penalizing offenders. Could oxytocin be involved in the social aspects of the religious experience? Dr. De Dreu sees oxytocin’s effects as being very general, and no more likely to be associated with the religious experience than with soccer hooliganism. “When people get together with others who share their values, that drives up the level of oxytocin,” he said.

For military commanders, nothing is more important than the group cohesion of their soldiers, for which oxytocin might now seem the ideal prescription. But this assumption is a bridge too far, Dr. De Dreu said, given that his findings are based only on lab experiments.

What does it mean that a chemical basis for ethnocentrism is embedded in the human brain? “In the ancestral environment it was very important for people to detect in others whether they had a long-term commitment to the group,” Dr. De Dreu said. “Ethnocentrism is a very basic part of humans, and it’s not something we can change by education. That doesn’t mean that the negative aspects of it should be taken for granted.”

Bruno B. Averbeck, an expert on the brain’s emotional processes at the National Institute of Mental Health, said that the effects of oxytocin described in Dr. De Dreu’s report were interesting but not necessarily dominant. The brain weighs emotional attitudes like those prompted by oxytocin against information available to the conscious mind. If there is no cognitive information in a situation in which a decision has to be made, like whether to trust a stranger about whom nothing is known, the brain will go with the emotional advice from its oxytocin system, but otherwise rational data will be weighed against the influence from oxytocin and may well override it, Dr. Averbeck said.

Dr. Averbeck said he was amazed that a substance like oxytocin can affect such a high-level human behavior. “It’s really surprising to me that this neurotransmitter can so specifically affect these social behaviors,” he said.

Moray eels’ heads are too narrow to create the negative pressure that most fish use to swallow prey. Quite possibly because of this, they have a second set of jaws in their throat called pharyngeal jaws, which also possess teeth. When feeding, morays launch these jaws into the mouth, where they grasp prey and transport it into the throat and digestive system. Moray eels are the only animal that uses pharyngeal jaws to actively capture and restrain prey.^[7][8][9] Larger morays are capable of seriously wounding humans.

Morays are carnivorous and feed primarily on other fish, cephalopods, molluscs, and crustaceans. Groupers, barracudas and sea snakes are among their few predators. There is a commercial fishery for several species, but some cause ciguatera fish poisoning.

Nature is absolutely fascinating.

fuckyeahfluiddynamics:

Not only is this demonstration one of my favorites, it’s a reader favorite, too. Even though I posted it nearly a year ago, I’ve had it resubmitted over and over. Here’s what I originally wrote:

Laminar flow (as opposed to turbulence) has the interesting property of reversibility. In this video, physicists demonstrate how flow between concentric cylinders can be reversed such that the initial fluid state is obtained (to within the limits of molecular diffusion, of course!)

For more examples, see the first half of this video.

The results of those videos might be surprising, but they highlight the difference between laminar flow and turbulence. In laminar flow, the motion of the dye is caused by molecular diffusion and momentum diffusion, the latter of which is exactly reversible. In turbulence, much of the fluid motion is tied up in momentum convection, which is irreversible. This is why you can “unstir” the glycerin but not the milk in your coffee.

ikenbot:

The Fabric of Space-time

Image: What happens to light as it passes through a point of space-time in where mass has been applied, as well as why objects in space orbit the way they do (planets, galaxies, clusters, etc.)

Also known as the Space-time Continuum, I’ve always been fascinated about the very space that holds the planet we live on, stars we see at night, solar system we observe, and supernovas we stargaze on telescopes. In astronomy you hear the term space-time get used a lot and I thought I’d highlight key features that describe what this fabric is. I find it odd that not that many people stop to think what holds us up, how are we suspended in space-time? Well, technically we’re not suspended. We’re constantly moving, constantly orbiting. And it’s not just Earth and the solar system joining in on this cosmic dance, you can include star clusters, galaxies, super clusters and even Blackholes, just about everything in our Universe. Keep in mind that even as you read this post, our solar system is orbiting the Milky Way galaxy, traveling at roughly 220 kilometers a second!

What is Space-time?

Einstein visualized gravity as a manifestation of the curvature of space-time - the three space dimensions and a fourth time dimension. Most of us cannot visualize a curvature of four dimensional space-time, so visualize a curved two dimensional rubber sheet. Placing a mass on the rubber sheet curves it downward like space-time curves in the presence of a mass. On such a rubber sheet a small mass can circle around the curvature produced by a large mass, just as planets orbit the Sun. Or a mass can roll straight downward just as an object falls to the Earth. Space-time being the very “material” these events and masses take place on.

Einstein explained gravity as a result of the curvature of space-time near the presence of a mass. The differences between general relativity and Newton’s law of gravity only become noticeable when the gravitational force is very strong.

Einstein’s general theory of relativity is one of the crowning intellectual achievements of the 20th century and led to such predictions as black holes, gravitational lenses, and the expanding universe. So far it has passed every experimental test with flying colors.

Info via Suite101

(Source: kenobi-wan-obi)

sciencesoup:

Why is there any Matter left in the Universe?

Every particle in existence has an antiparticle equivalent, which is almost identical except it carries the opposite electric charge. Matter is composed of normal particles and antimatter is composed of antiparticles—for example, while a proton and an electron form an ordinary hydrogen atom, an antiproton and a positron form an antihydrogen atom. Antimatter is created all the time in high-energy collisions, like when cosmic rays impact Earth’s atmosphere, but it immediately disappears because when matter and antimatter collide, they annihilate in a flash of pure energy. This makes it difficult to study experimentally, and neither can we find any evidence of a significant concentration of antimatter in the wider universe. The universe we know is dominated by ordinary matter—it makes up every person and planet and star—and yet if matter and antimatter were created equally at the birth of the universe, where has all the antimatter gone? This asymmetry is a perplexing question in physics, and several theories have been proposed to explain it. Perhaps nature favours matter reactions over antimatter ones; or perhaps matter and antimatter particles decay differently; or perhaps there are far flung regions composed primarily of antimatter, but they’re just beyond our visible universe. Researchers are currently trying to determine if such regions exist by studying colliding superclusters for high-energy signatures of annihilation, and by studying decay patterns in quarks.

(Image Credit: 1, 2)