Category Archives: BigBang

BigBang

Evolution machine: Genetic engineering on fast forward

[div class=attrib]From the New Scientist:[end-div]

Automated genetic tinkering is just the start – this machine could be used to rewrite the language of life and create new species of humans

IT IS a strange combination of clumsiness and beauty. Sitting on a cheap-looking worktop is a motley ensemble of flasks, trays and tubes squeezed onto a home-made frame. Arrays of empty pipette tips wait expectantly. Bunches of black and grey wires adorn its corners. On the top, robotic arms slide purposefully back and forth along metal tracks, dropping liquids from one compartment to another in an intricately choreographed dance. Inside, bacteria are shunted through slim plastic tubes, and alternately coddled, chilled and electrocuted. The whole assembly is about a metre and a half across, and controlled by an ordinary computer.

Say hello to the evolution machine. It can achieve in days what takes genetic engineers years. So far it is just a prototype, but if its proponents are to be believed, future versions could revolutionise biology, allowing us to evolve new organisms or rewrite whole genomes with ease. It might even transform humanity itself.

These days everything from your food and clothes to the medicines you take may well come from genetically modified plants or bacteria. The first generation of engineered organisms has been a huge hit with farmers and manufacturers – if not consumers. And this is just the start. So far organisms have only been changed in relatively crude and simple ways, often involving just one or two genes. To achieve their grander ambitions, such as creating algae capable of churning out fuel for cars, genetic engineers are now trying to make far more sweeping changes.

[div class=attrib]More from theSource here.[end-div]

BigBang

Nick Risinger’s Photopic Sky Survey

Big science covering scales from the microscopic to the vastness of the universe continues to deliver stunning new insights, now on a daily basis. I takes huge machines such as the Tevatron at Fermilab, CERN’s Large Hadron Collider, NASA’s Hubble Telescope and the myriad other detectors, arrays, spectrometers, particle smashers to probe some of our ultimate questions. The results from these machines bring us fantastic new perspectives and often show us remarkable pictures of the very small and very large.

Then there is Nick Risinger’s Photopic Sky Survey. No big science, no vast machines — just Nick Risinger, accompanied by retired father, camera equipment and 45,000 miles of travels capturing our beautiful night sky as never before.

[div class=attrib]From Nick Risinger:[end-div]

The Photopic Sky Survey is a 5,000 megapixel photograph of the entire night sky stitched together from 37,440 exposures. Large in size and scope, it portrays a world far beyond the one beneath our feet and reveals our familiar Milky Way with unfamiliar clarity.

It was clear that such a survey would be quite difficult visually hopping from one area of the sky to the next—not to mention possible lapses in coverage—so this called for a more systematic approach. I divided the sky into 624 uniformly spaced areas and entered their coordinates into the computer which gave me assurance that I was on target and would finish without any gaps. Each frame received a total of 60 exposures: 4 short, 4 medium, and 4 long shots for each camera which would help to reduce the amount of noise, overhead satellite trails and other unwanted artifacts.

And so it was with this blueprint that I worked my way through the sky, frame by frame, night after night. The click-clack of the shutters opening and closing became a staccato soundtrack for the many nights spent under the stars. Occasionally, the routine would be pierced by a bright meteor or the cry of a jackal, each compelling a feeling of eerie beauty that seemed to hang in the air. It was an experience that will stay with me a lifetime.

A truly remarkable and beautiful achievement. This is what focus and passion can achieve.

[div class=attrib]More from theSource here.[end-div]

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Cosmic Smoothness

Simulations based on the standard cosmological model, as shown here, indicate that on very large distance scales, galaxies should be uniformly distributed. But observations show a clumpier distribution than expected. (The length bar represents about $2.3$ billion light years.)[div class=attrib]From American Physical Society, Michael J. Hudson:[end-div]

The universe is expected to be very nearly homogeneous in density on large scales. In Physical Review Letters, Shaun Thomas and colleagues from University College London analyze measurements of the density of galaxies on the largest spatial scales so far—billions of light years—and find that the universe is less smooth than expected. If it holds up, this result will have important implications for our understanding of dark matter, dark energy, and perhaps gravity itself.

In the current standard cosmological model, the average mass-energy density of the observable universe consists of 5% normal matter (most of which is hydrogen and helium), 23% dark matter, and 72% dark energy. The dark energy is assumed to be uniform, but the normal and dark matter are not. The balance between matter and dark energy determines both how the universe expands and how regions of unusually high or low matter density evolve with time.

The same cosmological model predicts the statistics of the nonuniform structure and their dependence on spatial scale. On scales that are small by cosmological standards, fluctuations in the matter density are comparable to its mean, in agreement with what is seen: matter is clumped into galaxies, clusters of galaxies, and filaments of the “cosmic web.” On larger scales, however, the contrast of the structures compared to the mean density decreases. On the largest cosmological scales, these density fluctuations are small in amplitude compared to the average density of the universe and so are well described by linear perturbation theory (see simulation results in Fig. 1). Moreover, these perturbations can be calibrated at early times directly from the cosmic microwave background (CMB), a snapshot of the universe from when it was only 380,000 years old. Despite the fact that only 5% of the Universe is well understood, this model is an excellent fit to data spanning a wide range of spatial scales as the fluctuations evolved from the time of the CMB to the present age of the universe, some 13.8 billion years. On the largest scales, dark energy drives accelerated expansion of the universe. Because this aspect of the standard model is least understood, it is important to test it on these scales.

Thomas et al. use publicly-released catalogs from the Sloan Digital Sky Survey to select more than 700,000 galaxies whose observed colors indicate a significant redshift and are therefore presumed to be at large cosmological distances. They use the redshift of the galaxies, combined with their observed positions on the sky, to create a rough three-dimensional map of the galaxies in space and to assess the homogeneity on scales of a couple of billion light years. One complication is that Thomas et al. measure the density of galaxies, not the density of all matter, but we expect that fluctuations of these two densities about their means to be proportional; the constant of proportionality can be calibrated by observations on smaller scales. Indeed, on small scales the galaxy data are in good agreement with the standard model. On the largest scales, the fluctuations in galaxy density are expected to be of order a percent of the mean density, but Thomas et al. find fluctuations double this prediction. This result then suggests that the universe is less homogeneous than expected.

This result is not entirely new: previous studies based on subsets of the data studied by Thomas et al. showed the same effect, albeit with a lower statistical significance. In addition, there are other ways of probing the large-scale mass distribution. For example, inhomogeneities in the mass distribution lead to inhomogeneities in the local rate of expansion. Some studies have suggested that, on very large scales, this expansion too is less homogeneous than the model predictions.

Future large-scale surveys will produce an avalanche of data. These surveys will allow the methods employed by Thomas et al. and others to be extended to still larger scales. Of course, the challenge for these future surveys will be to correct for the systematic effects to even greater accuracy.

[div class=attrib]More from theSource here.[end-div]

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How Self-Control Works

[div class=attrib]From Scientific American:[end-div]

The scientific community is increasingly coming to realize how central self-control is to many important life outcomes. We have always known about the impact of socioeconomic status and IQ, but these are factors that are highly resistant to interventions. In contrast, self-control may be something that we can tap into to make sweeping improvements life outcomes.

If you think about the environment we live in, you will notice how it is essentially designed to challenge every grain of our self-control. Businesses have the means and motivation to get us to do things NOW, not later. Krispy Kreme wants us to buy a dozen doughnuts while they are hot; Best Buy wants us to buy a television before we leave the store today; even our physicians want us to hurry up and schedule our annual checkup.

There is not much place for waiting in today’s marketplace. In fact you can think about the whole capitalist system as being designed to get us to take actions and spend money now – and those businesses that are more successful in that do better and prosper (at least in the short term).  And this of course continuously tests our ability to resist temptation and exercise self-control.

It is in this very environment that it’s particularly important to understand what’s going on behind the mysterious force of self-control.

[div class=attrib]More from theSource here.[end-div]

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A New Tool for Creative Thinking: Mind-Body Dissonance

[div class=attrib]From Scientific American:[end-div]

A New Tool for Creative Thinking: Mind-Body Dissonance

Did you ever get the giggles during a religious service or some other serious occasion?  Did you ever have to smile politely when you felt like screaming?  In these situations, the emotions that we are required to express differ from the ones we are feeling inside.  That can be stressful, unpleasant, and exhausting.  Normally our minds and our bodies are in harmony.  When facial expressions or posture depart from how we feel, we experience what two psychologists at Northwestern University, Li Huang and Adam Galinsky, call mind–body dissonance.  And in a fascinating new paper, they show that such awkward clashes between mind and body can actually be useful: they help us think more expansively.

Ask yourself, would you say that a camel is a vehicle?  Would you describe a handbag as an item of clothing?  Your default answer might be negative, but there’s a way in which the camels can be regarded as forms of transport, and handbags can certainly be said to dress up an outfit.  When we think expansively, we think about categories more inclusively, we stop privileging the average cases, and extend our horizons to the atypical or exotic.  Expansive thought can be regarded a kind of creativity, and an opportunity for new insights.

Huang and Galinsky have shown that mind–body dissonance can make us think expansively.  In a clever series of studies, they developed a way to get people’s facial expressions to depart from their emotional experiences.  Participants were asked to either hold a pen between their teeth, forcing an unwitting smile, or to affix two golf tees in a particular position on their foreheads, unwittingly forcing an expression of sadness.  While in these facial configurations subjects were asked to recall happy and sad events or listen to happy and sad music.

[div class=attrib]More from theSource here.[end-div]

BigBang

The Top Ten Daily Consequences of Having Evolved

[div class=attrib]From Smithsonian.com:[end-div]

Natural selection acts by winnowing the individuals of each generation, sometimes clumsily, as old parts and genes are co-opted for new roles. As a result, all species inhabit bodies imperfect for the lives they live. Our own bodies are worse off than most simply because of the many differences between the wilderness in which we evolved and the modern world in which we live. We feel the consequences every day. Here are ten.

1. Our cells are weird chimeras
Perhaps a billion years ago, a single-celled organism arose that would ultimately give rise to all of the plants and animals on Earth, including us. This ancestor was the result of a merging: one cell swallowed, imperfectly, another cell. The predator provided the outsides, the nucleus and most of the rest of the chimera. The prey became the mitochondrion, the cellular organ that produces energy. Most of the time, this ancient symbiosis proceeds amicably. But every so often, our mitochondria and their surrounding cells fight. The result is diseases, such as mitochondrial myopathies (a range of muscle diseases) or Leigh’s disease (which affects the central nervous system).

2. Hiccups
The first air-breathing fish and amphibians extracted oxygen using gills when in the water and primitive lungs when on land—and to do so, they had to be able to close the glottis, or entryway to the lungs, when underwater. Importantly, the entryway (or glottis) to the lungs could be closed. When underwater, the animals pushed water past their gills while simultaneously pushing the glottis down. We descendants of these animals were left with vestiges of their history, including the hiccup. In hiccupping, we use ancient muscles to quickly close the glottis while sucking in (albeit air, not water). Hiccups no longer serve a function, but they persist without causing us harm—aside from frustration and occasional embarrassment. One of the reasons it is so difficult to stop hiccupping is that the entire process is controlled by a part of our brain that evolved long before consciousness, and so try as you might, you cannot think hiccups away.

3. Backaches
The backs of vertebrates evolved as a kind of horizontal pole under which guts were slung. It was arched in the way a bridge might be arched, to support weight. Then, for reasons anthropologists debate long into the night, our hominid ancestors stood upright, which was the bodily equivalent of tipping a bridge on end. Standing on hind legs offered advantages—seeing long distances, for one, or freeing the hands to do other things—but it also turned our backs from an arched bridge to an S shape. The letter S, for all its beauty, is not meant to support weight and so our backs fail, consistently and painfully.

[div class=attrib]More from theSource here.[end-div]

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Andre Geim: in praise of graphene

[div class=attrib]From Nature:[end-div]

Nobel laureate explains why the carbon sheets deserved to win this year’s prize.

This year’s Nobel Prize in Physics went to the discoverers of the one-atom-thick sheets of carbon known as graphene. Andre Geim of the University of Manchester, UK, who shared the award with his colleague Konstantin Novoselov, tells Nature why graphene deserves the prize, and why he hasn’t patented it.

In one sentence, what is graphene?

Graphene is a single plane of graphite that has to be pulled out of bulk graphite to show its amazing properties.

What are these properties?

It’s the thinnest possible material you can imagine. It also has the largest surface-to-weight ratio: with one gram of graphene you can cover several football pitches (in Manchester, you know, we measure surface area in football pitches). It’s also the strongest material ever measured; it’s the stiffest material we know; it’s the most stretchable crystal. That’s not the full list of superlatives, but it’s pretty impressive.

A lot of people expected you to win, but not so soon after the discovery in 2004. Were you expecting it?

I didn’t think it would happen this year. I was thinking about next year or maybe 2014. I slept quite soundly without much expectation. Yeah, it’s good, it’s good.

Graphene has won, but not that much has actually been done with it yet. Do you think it was too soon?

No. The prize, if you read the citation, was given for the properties of graphene; it wasn’t given for expectations that have not yet been realized. Ernest Rutherford’s 1908 Nobel Prize in Chemistry wasn’t given for the nuclear power station — he wouldn’t have survived that long — it was given for showing how interesting atomic physics could be. I believe the Nobel prize committee did a good job.

Do you think that carbon nanotubes were unfairly overlooked?

It’s difficult to judge; I’m a little afraid of being biased. If the prize had been given for bringing graphene to the attention of the community, then it would have been unfair to take it away from carbon nanotubes. But it was given for graphene’s properties, and I think carbon nanotubes did not deliver that range of properties. Everyone knows that — in terms of physics, not applications — carbon nanotubes were not as successful as graphene.

Why do you think graphene has become so popular in the physics community?

I would say there are three important things about graphene. It’s two-dimensional, which is the best possible number for studying fundamental physics. The second thing is the quality of graphene, which stems from its extremely strong carbon–carbon bonds. And finally, the system is also metallic.

What do you think graphene will be used for first?

Two or three months ago, I was in South Korea, and I was shown a graphene roadmap, compiled by Samsung. On this roadmap were approximately 50 dots, corresponding to particular applications. One of the closest applications with a reasonable market value was a flexible touch screen. Samsung expects something within two to three years.

[div class=attrib]More from theSource here.[end-div]

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The Evolution of the Physicist’s Picture of Nature

[div class=attrib]From Scientific American:[end-div]

Editor’s Note: We are republishing this article by Paul Dirac from the May 1963 issue of Scientific American, as it might be of interest to listeners to the June 24, 2010, and June 25, 2010 Science Talk podcasts, featuring award-winning writer and physicist Graham Farmelo discussing The Strangest Man, his biography of the Nobel Prize-winning British theoretical physicist.

In this article I should like to discuss the development of general physical theory: how it developed in the past and how one may expect it to develop in the future. One can look on this continual development as a process of evolution, a process that has been going on for several centuries.

The first main step in this process of evolution was brought about by Newton. Before Newton, people looked on the world as being essentially two-dimensional-the two dimensions in which one can walk about-and the up-and-down dimension seemed to be something essentially different. Newton showed how one can look on the up-and-down direction as being symmetrical with the other two directions, by bringing in gravitational forces and showing how they take their place in physical theory. One can say that Newton enabled us to pass from a picture with two-dimensional symmetry to a picture with three-dimensional symmetry.

Einstein made another step in the same direction, showing how one can pass from a picture with three-dimensional symmetry to a picture with four­dimensional symmetry. Einstein brought in time and showed how it plays a role that is in many ways symmetrical with the three space dimensions. However, this symmetry is not quite perfect. With Einstein’s picture one is led to think of the world from a four-dimensional point of view, but the four dimensions are not completely symmetrical. There are some directions in the four-dimensional picture that are different from others: directions that are called null directions, along which a ray of light can move; hence the four-dimensional picture is not completely symmetrical. Still, there is a great deal of symmetry among the four dimensions. The only lack of symmetry, so far as concerns the equations of physics, is in the appearance of a minus sign in the equations with respect to the time dimension as compared with the three space dimensions [see top equation in diagram].

four-dimensional symmetry equation and Schrodinger's equationsWe have, then, the development from the three-dimensional picture of the world to the four-dimensional picture. The reader will probably not be happy with this situation, because the world still appears three-dimensional to his consciousness. How can one bring this appearance into the four-dimensional picture that Einstein requires the physicist to have?

What appears to our consciousness is really a three-dimensional section of the four-dimensional picture. We must take a three-dimensional section to give us what appears to our consciousness at one time; at a later time we shall have a different three-dimensional section. The task of the physicist consists largely of relating events in one of these sections to events in another section referring to a later time. Thus the picture with four­dimensional symmetry does not give us the whole situation. This becomes particularly important when one takes into account the developments that have been brought about by quantum theory. Quantum theory has taught us that we have to take the process of observation into account, and observations usually require us to bring in the three-dimensional sections of the four-dimensional picture of the universe.

The special theory of relativity, which Einstein introduced, requires us to put all the laws of physics into a form that displays four-dimensional symmetry. But when we use these laws to get results about observations, we have to bring in something additional to the four-dimensional symmetry, namely the three-dimensional sections that describe our consciousness of the universe at a certain time.

Einstein made another most important contribution to the development of our physical picture: he put forward the general theory of relativity, which requires us to suppose that the space of physics is curved. Before this physicists had always worked with a flat space, the three-dimensional flat space of Newton which was then extended to the four­dimensional flat space of special relativity. General relativity made a really important contribution to the evolution of our physical picture by requiring us to go over to curved space. The general requirements of this theory mean that all the laws of physics can be formulated in curved four-dimensional space, and that they show symmetry among the four dimensions. But again, when we want to bring in observations, as we must if we look at things from the point of view of quantum theory, we have to refer to a section of this four-dimensional space. With the four-dimensional space curved, any section that we make in it also has to be curved, because in general we cannot give a meaning to a flat section in a curved space. This leads us to a picture in which we have to take curved three­dimensional sections in the curved four­dimensional space and discuss observations in these sections.

During the past few years people have been trying to apply quantum ideas to gravitation as well as to the other phenomena of physics, and this has led to a rather unexpected development, namely that when one looks at gravitational theory from the point of view of the sections, one finds that there are some degrees of freedom that drop out of the theory. The gravitational field is a tensor field with 10 components. One finds that six of the components are adequate for describing everything of physical importance and the other four can be dropped out of the equations. One cannot, however, pick out the six important components from the complete set of 10 in any way that does not destroy the four-dimensional symmetry. Thus if one insists on preserving four-dimensional symmetry in the equations, one cannot adapt the theory of gravitation to a discussion of measurements in the way quantum theory requires without being forced to a more complicated description than is needed bv the physical situation. This result has led me to doubt how fundamental the four-dimensional requirement in physics is. A few decades ago it seemed quite certain that one had to express the whole of physics in four­dimensional form. But now it seems that four-dimensional symmetry is not of such overriding importance, since the description of nature sometimes gets simplified when one departs from it.

Now I should like to proceed to the developments that have been brought about by quantum theory. Quantum theory is the discussion of very small things, and it has formed the main subject of physics for the past 60 years. During this period physicists have been amassing quite a lot of experimental information and developing a theory to correspond to it, and this combination of theory and experiment has led to important developments in the physicist’s picture of the world.

[div class=attrib]More from theSource here.[end-div]

BigBang

Immaculate creation: birth of the first synthetic cell

[div class=attrib]From the New Scientist:[end-div]

For the first time, scientists have created life from scratch – well, sort of. Craig Venter‘s team at the J. Craig Venter Institute in Rockville, Maryland, and San Diego, California, has made a bacterial genome from smaller DNA subunits and then transplanted the whole thing into another cell. So what exactly is the science behind the first synthetic cell, and what is its broader significance?

What did Venter’s team do?

The cell was created by stitching together the genome of a goat pathogen called Mycoplasma mycoides from smaller stretches of DNA synthesised in the lab, and inserting the genome into the empty cytoplasm of a related bacterium. The transplanted genome booted up in its host cell, and then divided over and over to make billions of M. mycoides cells.

Venter and his team have previously accomplished both feats – creating a synthetic genome and transplanting a genome from one bacterium into another – but this time they have combined the two.

“It’s the first self-replicating cell on the planet that’s parent is a computer,” says Venter, referring to the fact that his team converted a cell’s genome that existed as data on a computer into a living organism.

How can they be sure that the new bacteria are what they intended?

Venter and his team introduced several distinctive markers into their synthesised genome. All of them were found in the synthetic cell when it was sequenced.

These markers do not make any proteins, but they contain the names of 46 scientists on the project and several quotations written out in a secret code. The markers also contain the key to the code.

Crack the code and you can read the messages, but as a hint, Venter revealed the quotations: “To live, to err, to fall, to triumph, to recreate life out of life,” from James Joyce’s A Portrait of the Artist as a Young Man; “See things not as they are but as they might be,” which comes from American Prometheus, a biography of nuclear physicist Robert Oppenheimer; and Richard Feynman’s famous words: “What I cannot build I cannot understand.”

Does this mean they created life?

It depends on how you define “created” and “life”. Venter’s team made the new genome out of DNA sequences that had initially been made by a machine, but bacteria and yeast cells were used to stitch together and duplicate the million base pairs that it contains. The cell into which the synthetic genome was then transplanted contained its own proteins, lipids and other molecules.

Venter himself maintains that he has not created life . “We’ve created the first synthetic cell,” he says. “We definitely have not created life from scratch because we used a recipient cell to boot up the synthetic chromosome.”

Whether you agree or not is a philosophical question, not a scientific one as there is no biological difference between synthetic bacteria and the real thing, says Andy Ellington, a synthetic biologist at the University of Texas in Austin. “The bacteria didn’t have a soul, and there wasn’t some animistic property of the bacteria that changed,” he says.

What can you do with a synthetic cell?

Venter’s work was a proof of principle, but future synthetic cells could be used to create drugs, biofuels and other useful products. He is collaborating with Exxon Mobil to produce biofuels from algae and with Novartis to create vaccines.

“As soon as next year, the flu vaccine you get could be made synthetically,” Venter says.

Ellington also sees synthetic bacteria as having potential as a scientific tool. It would be interesting, he says, to create bacteria that produce a new amino acid – the chemical units that make up proteins – and see how these bacteria evolve, compared with bacteria that produce the usual suite of amino acids. “We can ask these questions about cyborg cells in ways we never could before.”

[div class=attrib]More from theSource here.[end-div]

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The Search for Genes Leads to Unexpected Places

[div class=attrib]From The New York Times:[end-div]

Edward M. Marcotte is looking for drugs that can kill tumors by stopping blood vessel growth, and he and his colleagues at the University of Texas at Austin recently found some good targets — five human genes that are essential for that growth. Now they’re hunting for drugs that can stop those genes from working. Strangely, though, Dr. Marcotte did not discover the new genes in the human genome, nor in lab mice or even fruit flies. He and his colleagues found the genes in yeast.

“On the face of it, it’s just crazy,” Dr. Marcotte said. After all, these single-cell fungi don’t make blood vessels. They don’t even make blood. In yeast, it turns out, these five genes work together on a completely unrelated task: fixing cell walls.

Crazier still, Dr. Marcotte and his colleagues have discovered hundreds of other genes involved in human disorders by looking at distantly related species. They have found genes associated with deafness in plants, for example, and genes associated with breast cancer in nematode worms. The researchers reported their results recently in The Proceedings of the National Academy of Sciences.

The scientists took advantage of a peculiar feature of our evolutionary history. In our distant, amoeba-like ancestors, clusters of genes were already forming to work together on building cell walls and on other very basic tasks essential to life. Many of those genes still work together in those same clusters, over a billion years later, but on different tasks in different organisms.

[div class=attrib]More from theSource here.[end-div]

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Why Athletes Are Geniuses

[div class=attrib]From Discover:[end-div]

The qualities that set a great athlete apart from the rest of us lie not just in the muscles and the lungs but also between the ears. That’s because athletes need to make complicated decisions in a flash. One of the most spectacular examples of the athletic brain operating at top speed came in 2001, when the Yankees were in an American League playoff game with the Oakland Athletics. Shortstop Derek Jeter managed to grab an errant throw coming in from right field and then gently tossed the ball to catcher Jorge Posada, who tagged the base runner at home plate. Jeter’s quick decision saved the game—and the series—for the Yankees. To make the play, Jeter had to master both conscious decisions, such as whether to intercept the throw, and unconscious ones. These are the kinds of unthinking thoughts he must make in every second of every game: how much weight to put on a foot, how fast to rotate his wrist as he releases a ball, and so on.

In recent years neuroscientists have begun to catalog some fascinating differences between average brains and the brains of great athletes. By understanding what goes on in athletic heads, researchers hope to understand more about the workings of all brains—those of sports legends and couch potatoes alike.

As Jeter’s example shows, an athlete’s actions are much more than a set of automatic responses; they are part of a dynamic strategy to deal with an ever-changing mix of intricate challenges. Even a sport as seemingly straightforward as pistol shooting is surprisingly complex. A marksman just points his weapon and fires, and yet each shot calls for many rapid decisions, such as how much to bend the elbow and how tightly to contract the shoulder muscles. Since the shooter doesn’t have perfect control over his body, a slight wobble in one part of the arm may require many quick adjustments in other parts. Each time he raises his gun, he has to make a new calculation of what movements are required for an accurate shot, combining previous experience with whatever variations he is experiencing at the moment.

To explain how brains make these on-the-fly decisions, Reza Shadmehr of Johns Hopkins University and John Krakauer of Columbia University two years ago reviewed studies in which the brains of healthy people and of brain-damaged patients who have trouble controlling their movements were scanned. They found that several regions of the brain collaborate to make the computations needed for detailed motor actions. The brain begins by setting a goal—pick up the fork, say, or deliver the tennis serve—and calculates the best course of action to reach it. As the brain starts issuing commands, it also begins to make predictions about what sort of sensations should come back from the body if it achieves the goal. If those predictions don’t match the actual sensations, the brain then revises its plan to reduce error. Shadmehr and Krakauer’s work demonstrates that the brain does not merely issue rigid commands; it also continually updates its solution to the problem of how to move the body. Athletes may perform better than the rest of us because their brains can find better solutions than ours do.

[div class=attrib]More from theSource here.[end-div]

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The Real Rules for Time Travelers

[div class=attrib]From Discover:[end-div]

People all have their own ideas of what a time machine would look like. If you are a fan of the 1960 movie version of H. G. Wells’s classic novel, it would be a steampunk sled with a red velvet chair, flashing lights, and a giant spinning wheel on the back. For those whose notions of time travel were formed in the 1980s, it would be a souped-up stainless steel sports car. Details of operation vary from model to model, but they all have one thing in common: When someone actually travels through time, the machine ostentatiously dematerializes, only to reappear many years in the past or future. And most people could tell you that such a time machine would never work, even if it looked like a DeLorean.

They would be half right: That is not how time travel might work, but time travel in some other form is not necessarily off the table. Since time is kind of like space (the four dimensions go hand in hand), a working time machine would zoom off like a rocket rather than disappearing in a puff of smoke. Einstein described our universe in four dimensions: the three dimensions of space and one of time. So traveling back in time is nothing more or less than the fourth-dimensional version of walking in a circle. All you would have to do is use an extremely strong gravitational field, like that of a black hole, to bend space-time. From this point of view, time travel seems quite difficult but not obviously impossible.

These days, most people feel comfortable with the notion of curved space-time. What they trip up on is actually a more difficult conceptual problem, the time travel paradox. This is the worry that someone could go back in time and change the course of history. What would happen if you traveled into the past, to a time before you were born, and murdered your parents? Put more broadly, how do we avoid changing the past as we think we have already experienced it? At the moment, scientists don’t know enough about the laws of physics to say whether these laws would permit the time equivalent of walking in a circle—or, in the parlance of time travelers, a “closed timelike curve.” If they don’t permit it, there is obviously no need to worry about paradoxes. If physics is not an obstacle, however, the problem could still be constrained by logic. Do closed timelike curves necessarily lead to paradoxes?

If they do, then they cannot exist, simple as that. Logical contradictions cannot occur. More specifically, there is only one correct answer to the question “What happened at the vicinity of this particular event in space-time?” Something happens: You walk through a door, you are all by yourself, you meet someone else, you somehow never showed up, whatever it may be. And that something is whatever it is, and was whatever it was, and will be whatever it will be, once and forever. If, at a certain event, your grandfather and grandmother were getting it on, that’s what happened at that event. There is nothing you can do to change it, because it happened. You can no more change events in your past in a space-time with closed timelike curves than you can change events that already happened in ordinary space-time, with no closed timelike curves.

[div class=attrib]More from theSource here.[end-div]

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Human Culture, an Evolutionary Force

[div class=attrib]From The New York Times:[end-div]

As with any other species, human populations are shaped by the usual forces of natural selection, like famine, disease or climate. A new force is now coming into focus. It is one with a surprising implication — that for the last 20,000 years or so, people have inadvertently been shaping their own evolution.

The force is human culture, broadly defined as any learned behavior, including technology. The evidence of its activity is the more surprising because culture has long seemed to play just the opposite role. Biologists have seen it as a shield that protects people from the full force of other selective pressures, since clothes and shelter dull the bite of cold and farming helps build surpluses to ride out famine.

Because of this buffering action, culture was thought to have blunted the rate of human evolution, or even brought it to a halt, in the distant past. Many biologists are now seeing the role of culture in a quite different light.

Although it does shield people from other forces, culture itself seems to be a powerful force of natural selection. People adapt genetically to sustained cultural changes, like new diets. And this interaction works more quickly than other selective forces, “leading some practitioners to argue that gene-culture co-evolution could be the dominant mode of human evolution,” Kevin N. Laland and colleagues wrote in the February issue of Nature Reviews Genetics. Dr. Laland is an evolutionary biologist at the University of St. Andrews in Scotland.

The idea that genes and culture co-evolve has been around for several decades but has started to win converts only recently. Two leading proponents, Robert Boyd of the University of California, Los Angeles, and Peter J. Richerson of the University of California, Davis, have argued for years that genes and culture were intertwined in shaping human evolution. “It wasn’t like we were despised, just kind of ignored,” Dr. Boyd said. But in the last few years, references by other scientists to their writings have “gone up hugely,” he said.

The best evidence available to Dr. Boyd and Dr. Richerson for culture being a selective force was the lactose tolerance found in many northern Europeans. Most people switch off the gene that digests the lactose in milk shortly after they are weaned, but in northern Europeans — the descendants of an ancient cattle-rearing culture that emerged in the region some 6,000 years ago — the gene is kept switched on in adulthood.

Lactose tolerance is now well recognized as a case in which a cultural practice — drinking raw milk — has caused an evolutionary change in the human genome. Presumably the extra nutrition was of such great advantage that adults able to digest milk left more surviving offspring, and the genetic change swept through the population.

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The Graphene Revolution

[div class=attrib]From Discover:[end-div]

Flexible, see-through, one-atom-thick sheets of carbon could be a key component for futuristic solar cells, batteries, and roll-up LCD screens—and perhaps even microchips.

Under a transmission electron microscope it looks deceptively simple: a grid of hexa­gons resembling a volleyball net or a section of chicken wire. But graphene, a form of carbon that can be produced in sheets only one atom thick, seems poised to shake up the world of electronics. Within five years, it could begin powering faster and better transistors, computer chips, and LCD screens, according to researchers who are smitten with this new supermaterial.

Graphene’s standout trait is its uncanny facility with electrons, which can travel much more quickly through it than they can through silicon. As a result, graphene-based computer chips could be thousands of times as efficient as existing ones. “What limits conductivity in a normal material is that electrons will scatter,” says Michael Strano, a chemical engineer at MIT. “But with graphene the electrons can travel very long distances without scattering. It’s like the thinnest, most stable electrical conducting framework you can think of.”

In 2009 another MIT researcher, Tomas Palacios, devised a graphene chip that doubles the frequency of an electromagnetic signal. Using multiple chips could make the outgoing signal many times higher in frequency than the original. Because frequency determines the clock speed of the chip, boosting it enables faster transfer of data through the chip. Graphene’s extreme thinness means that it is also practically transparent, making it ideal for transmitting signals in devices containing solar cells or LEDs.

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J. Craig Venter

[div class=attrib]From Discover:[end-div]

J. Craig Venter keeps riding the cusp of each new wave in biology. When researchers started analyzing genes, he launched the Institute for Genomic Research (TIGR), decoding the genome of a bacterium for the first time in 1992. When the government announced its plan to map the human genome, he claimed he would do it first—and then he delivered results in 2001, years ahead of schedule. Armed with a deep understanding of how DNA works, Venter is now moving on to an even more extraordinary project. Starting with the stunning genetic diversity that exists in the wild, he is aiming to build custom-designed organisms that could produce clean energy, help feed the planet, and treat cancer. Venter has already transferred the genome of one species into the cell body of another. This past year he reached a major milestone, using the machinery of yeast to manufacture a genome from scratch. When he combines the steps—perhaps next year—he will have crafted a truly synthetic organism. Senior editor Pamela Weintraub discussed the implications of these efforts with Venter in DISCOVER’s editorial offices.

Here you are talking about constructing life, but you started out in deconstruction: charting the human genome, piece by piece.
Actually, I started out smaller, studying the adrenaline receptor. I was looking at one protein and its single gene for a decade. Then, in the late 1980s, I was drawn to the idea of the whole genome, and I stopped everything and switched my lab over. I had the first automatic DNA sequencer. It was the ultimate in reductionist biology—getting down to the genetic code, interpreting what it meant, including all 6 billion letters of my own genome. Only by understanding things at that level can we turn around and go the other way.

In your latest work you are trying to create “synthetic life.” What is that?
It’s a catchy phrase that people have begun using to replace “molecular biology.” The term has been overused, so we have defined a separate field that we call synthetic genomics—the digitization of biology using only DNA and RNA. You start by sequencing genomes and putting their digital code into a computer. Then you use the computer to take that information and design new life-forms.

How do you build a life-form? Throw in some mito­chondria here and some ribosomes there, surround ?it all with a membrane—?and voilà?
We started down that road, but now we are coming from the other end. We’re starting with the accomplishments of three and a half billion years of evolution by using what we call the software of life: DNA. Our software builds its own hardware. By writing new software, we can come up with totally new species. It would be as if once you put new software in your computer, somehow a whole new machine would materialize. We’re software engineers rather than construction workers.

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Five Big Additions to Darwin’s Theory of Evolution

[div class=attrib]From Discover:[end-div]

Charles Darwin would have turned 200 in 2009, the same year his book On the Origin of Species celebrated its 150th anniversary. Today, with the perspective of time, Darwin’s theory of evolution by natural selection looks as impressive as ever. In fact, the double anniversary year saw progress on fronts that Darwin could never have anticipated, bringing new insights into the origin of life—a topic that contributed to his panic attacks, heart palpitations, and, as he wrote, “for 25 years extreme spasmodic daily and nightly flatulence.” One can only dream of what riches await in the biology textbooks of 2159.

1. Evolution happens on the inside, too. The battle for survival is waged not just between the big dogs but within the dog itself, as individual genes jockey for prominence. From the moment of conception, a father’s genes favor offspring that are large, strong, and aggressive (the better to court the ladies), while the mother’s genes incline toward smaller progeny that will be less of a burden, making it easier for her to live on and procreate. Genome-versus-genome warfare produces kids that are somewhere in between.

Not all genetic conflicts are resolved so neatly. In flour beetles, babies that do not inherit the selfish genetic element known as Medea succumb to a toxin while developing in the egg. Some unborn mice suffer the same fate. Such spiteful genes have become widespread not by helping flour beetles and mice survive but by eliminating individuals that do not carry the killer’s code. “There are two ways of winning a race,” says Caltech biologist Bruce Hay. “Either you can be better than everyone else, or you can whack the other guys on the legs.”

Hay is trying to harness the power of such genetic cheaters, enlisting them in the fight against malaria. He created a Medea-like DNA element that spreads through experimental fruit flies like wildfire, permeating an entire population within 10 generations. This year he and his team have been working on encoding immune-system boosters into those Medea genes, which could then be inserted into male mosquitoes. If it works, the modified mosquitoes should quickly replace competitors who do not carry the new genes; the enhanced immune systems of the new mosquitoes, in turn, would resist the spread of the malaria parasite.

2. Identity is not written just in the genes. According to modern evolutionary theory, there is no way that what we eat, do, and encounter can override the basic rules of inheritance: What is in the genes stays in the genes. That single rule secured Darwin’s place in the science books. But now biologists are finding that nature can break those rules. This year Eva Jablonka, a theoretical biologist at Tel Aviv University, published a compendium of more than 100 hereditary changes that are not carried in the DNA sequence. This “epigenetic” inheritance spans bacteria, fungi, plants, and animals.

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Are Black Holes the Architects of the Universe?

[div class=attrib]From Discover:[end-div]

Black holes are finally winning some respect. After long regarding them as agents of destruction or dismissing them as mere by-products of galaxies and stars, scientists are recalibrating their thinking. Now it seems that black holes debuted in a constructive role and appeared unexpectedly soon after the Big Bang. “Several years ago, nobody imagined that there were such monsters in the early universe,” says Penn State astrophysicist Yuexing Li. “Now we see that black holes were essential in creating the universe’s modern structure.”

Black holes, tortured regions of space where the pull of gravity is so intense that not even light can escape, did not always have such a high profile. They were once thought to be very rare; in fact, Albert Einstein did not believe they existed at all. Over the past several decades, though, astronomers have realized that black holes are not so unusual after all: Supermassive ones, millions or billions of times as hefty as the sun, seem to reside at the center of most, if not all, galaxies. Still, many people were shocked in 2003 when a detailed sky survey found that giant black holes were already common nearly 13 billion years ago, when the universe was less than a billion years old. Since then, researchers have been trying to figure out where these primordial holes came from and how they influenced the cosmic events that followed.

In August, researchers at the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University ran a supercomputer simulation of the early universe and provided a tantalizing glimpse into the lives of the first black holes. The story began 200 million years after the Big Bang, when the universe’s first stars formed. These beasts, about 100 times the mass of the sun, were so large and energetic that they burned all their hydrogen fuel in just a few million years. With no more energy from hydrogen fusion to counteract the enormous inward pull of their gravity, the stars collapsed until all of their mass was compressed into a point of infinite density.

The first-generation black holes were puny compared with the monsters we see at the centers of galaxies today. They grew only slowly at first—adding just 1 percent to their bulk in the next 200 million years—because the hyperactive stars that spawned them had blasted away most of the nearby gas that they could have devoured. Nevertheless, those modest-size black holes left a big mark by performing a form of stellar birth control: Radiation from the trickle of material falling into the holes heated surrounding clouds of gas to about 5,000 degrees Fahrenheit, so hot that the gas could no longer easily coalesce. “You couldn’t really form stars in that stuff,” says Marcelo Alvarez, lead author of the Kavli study.

[div class=attrib]More from theSource here.[end-div]

[div class=attrib]Image courtesy of KIPAC/SLAC/M.Alvarez, T. Able, and J. Wise.[end-div]

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Will Our Universe Collide With a Neighboring One?

[div class=attrib]From Discover:[end-div]

Relaxing on an idyllic beach on Grand Cayman Island in the Caribbean, Anthony Aguirre vividly describes the worst natural disaster he can imagine. It is, in fact, probably the worst natural disaster that anyone could imagine. An asteroid impact would be small potatoes compared with this kind of event: a catastrophic encounter with an entire other universe.

As an alien cosmos came crashing into ours, its outer boundary would look like a wall racing forward at nearly the speed of light; behind that wall would lie a set of physical laws totally different from ours that would wreck everything they touched in our universe. “If we could see things in ultraslow motion, we’d see a big mirror in the sky rushing toward us because light would be reflected by the wall,” says Aguirre, a youthful physicist at the University of California at Santa Cruz. “After that we wouldn’t see anything—because we’d all be dead.”

There is a sober purpose behind this apocalyptic glee. Aguirre is one of a growing cadre of cosmologists who theorize that our universe is just one of many in a “multiverse” of universes. In their effort to grasp the implications of this idea, they have been calculating the odds that universes could interact with their neighbors or even smash into each other. While investigating what kind of gruesome end might result, they have stumbled upon a few surprises. There are tantalizing hints that our universe has already survived such a collision—and bears the scars to prove it.

Aguirre has organized a conference on Grand Cayman to address just such mind-boggling matters. The conversations here venture into multiverse mishaps and other matters of cosmological genesis and destruction. At first blush the setting seems incongruous: The tropical sun beats down dreamily, the smell of broken coconuts drifts from beneath the palm trees, and the ocean roars rhythmically in the background. But the locale is perhaps fitting. The winds are strong for this time of year, reminding the locals of hurricane Ivan, which devastated the capital city of George Town in 2004, lifting whole apartment blocks and transporting buildings across streets. In nature, peace and violence are never far from each other.

Much of today’s interest in multiple universes stems from concepts developed in the early 1980s by the pioneering cosmologists Alan Guth at MIT and Andrei Linde, then at the Lebedev Physical Institute in Moscow. Guth proposed that our universe went through an incredibly rapid growth spurt, known as inflation, in the first 10-30 second or so after the Big Bang. Such extreme expansion, driven by a powerful repulsive energy that quickly dissipated as the universe cooled, would solve many mysteries. Most notably, inflation could explain why the cosmos as we see it today is amazingly uniform in all directions. If space was stretched mightily during those first instants of existence, any extreme lumpiness or hot and cold spots would have immediately been smoothed out. This theory was modified by Linde, who had hit on a similar idea independently. Inflation made so much sense that it quickly became a part of the mainstream model of cosmology.

Soon after, Linde and Alex Vilenkin at Tufts University came to the startling realization that inflation may not have been a onetime event. If it could happen once, it could—and indeed should—happen again and again for eternity. Stranger still, every eruption of inflation would create a new bubble of space and energy. The result: an infinite progression of new universes, each bursting forth with its own laws of physics.

In such a bubbling multiverse of universes, it seems inevitable that universes would sometimes collide. But for decades cosmologists neglected this possibility, reckoning that the odds were small and that if it happened, the results would be irrelevant because anyone and anything near the collision would be annihilated.

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I Didn’t Sin—It Was My Brain

[div class=attrib]From Discover:[end-div]

Why does being bad feel so good? Pride, envy, greed, wrath, lust, gluttony, and sloth: It might sound like just one more episode of The Real Housewives of New Jersey, but this enduring formulation of the worst of human failures has inspired great art for thousands of years. In the 14th century Dante depicted ghoulish evildoers suffering for eternity in his masterpiece, The Divine Comedy. Medieval muralists put the fear of God into churchgoers with lurid scenarios of demons and devils. More recently George Balanchine choreographed their dance.

Today these transgressions are inspiring great science, too. New research is explaining where these behaviors come from and helping us understand why we continue to engage in them—and often celebrate them—even as we declare them to be evil. Techniques such as functional magnetic resonance imaging (fMRI), which highlights metabolically active areas of the brain, now allow neuroscientists to probe the biology behind bad intentions.

The most enjoyable sins engage the brain’s reward circuitry, including evolutionarily ancient regions such as the nucleus accumbens and hypothalamus; located deep in the brain, they provide us such fundamental feelings as pain, pleasure, reward, and punishment. More disagreeable forms of sin such as wrath and envy enlist the dorsal anterior cingulate cortex (dACC). This area, buried in the front of the brain, is often called the brain’s “conflict detector,” coming online when you are confronted with contradictory information, or even simply when you feel pain. The more social sins (pride, envy, lust, wrath) recruit the medial prefrontal cortex (mPFC), brain terrain just behind the forehead, which helps shape the awareness of self.

No understanding of temptation is complete without considering restraint, and neuroscience has begun to illuminate this process as well. As we struggle to resist, inhibitory cognitive control networks involving the front of the brain activate to squelch the impulse by tempering its appeal. Meanwhile, research suggests that regions such as the caudate—partly responsible for body movement and coordination—suppress the physical impulse. It seems to be the same whether you feel a spark of lechery, a surge of jealousy, or the sudden desire to pop somebody in the mouth: The two sides battle it out, the devilish reward system versus the angelic brain regions that hold us in check.

It might be too strong to claim that evolution has wired us for sin, but excessive indulgence in lust or greed could certainly put you ahead of your competitors. “Many of these sins you could think of as virtues taken to the extreme,” says Adam Safron, a research consultant at Northwestern University whose neuroimaging studies focus on sexual behavior. “From the perspective of natural selection, you want the organism to eat, to procreate, so you make them rewarding. But there’s a potential for that process to go beyond the bounds.”

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Stephen Hawking Is Making His Comeback

[div class=attrib]From Discover:[end-div]

As an undergraduate at Oxford University, Stephen William Hawking was a wise guy, a provocateur. He was popular, a lively coxswain for the crew team. Physics came easy. He slept through lectures, seldom studied, and criticized his professors. That all changed when he started graduate school at Cambridge in 1962 and subsequently learned that he had only a few years to live.

The symptoms first appeared while Hawking was still at Oxford. He could not row a scull as easily as he once had; he took a few bad, clumsy falls. A college doctor told him not to drink so much beer. By 1963 his condition had gotten bad enough that his mother brought him to a hospital in London, where he received the devastating diagnosis: motor neuron disease, as ALS is called in the United Kingdom. The prognosis was grim and final: rapid wasting of nerves and muscles, near-total paralysis, and death from respiratory failure in three to five years.

Not surprisingly, Hawking grew depressed, seeking solace in the music of Wagner (contrary to some media reports, however, he says he did not go on a drinking binge). And yet he did not disengage from life. Later in 1963 he met Jane Wilde, a student of medieval poetry at the University of London. They fell in love and resolved to make the most of what they both assumed would be a tragically short relationship. In 1965 they married, and Hawking returned to physics with newfound energy.

Also that year, Hawking had an encounter that led to his first major contribution to his field. The occasion was a talk at Kings College in London given by Roger Penrose, an eminent mathematician then at Birkbeck College. Penrose had just proved something remarkable and, for physicists, disturbing: Black holes, the light-trapping chasms in space-time that form in the aftermath of the collapse of massive stars, must all contain singularities—points where space, time, and the very laws of physics fall apart.

Before Penrose’s work, many physicists had regarded singularities as mere curiosities, permitted by Einstein’s theory of general relativity but unlikely to exist. The standard assumption was that a singularity could form only if a perfectly spherical star collapsed with perfect symmetry, the kind of ideal conditions that never occur in the real world. Penrose proved otherwise. He found that any star massive enough to form a black hole upon its death must create a singularity. This realization meant that the laws of physics could not be used to describe everything in the universe; the singularity was a cosmic abyss.

At a subsequent lecture, Hawking grilled Penrose on his ideas. “He asked some awkward questions,” Penrose says. “He was very much on the ball. I had probably been a bit vague in one of my statements, and he was sharpening it up a bit. I was a little alarmed that he noticed something that I had glossed over, and that he was able to spot it so quickly.”

Hawking had just renewed his search for a subject for his Ph.D. thesis, a project he had abandoned after receiving the ALS diagnosis. His condition had stabilized somewhat, and his future no longer looked completely bleak. Now he had his subject: He wanted to apply Penrose’s approach to the cosmos at large.

Physicists have known since 1929 that the universe is expanding. Hawking reasoned that if the history of the universe could be run backward, so that the universe was shrinking instead of expanding, it would behave (mathematically at least) like a collapsing star, the same sort of phenomenon Penrose had analyzed. Hawking’s work was timely. In 1965, physicists working at Bell Labs in New Jersey discovered the cosmic microwave background radiation, the first direct evidence that the universe began with the Big Bang. But was the Big Bang a singularity, or was it a concentrated, hot ball of energy—awesome and mind-bending, but still describable by the laws of physics?

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How Much of Your Memory Is True?

[div class=attrib]From Discover:[end-div]

Rita Magil was driving down a Montreal boulevard one sunny morning in 2002 when a car came blasting through a red light straight toward her. “I slammed the brakes, but I knew it was too late,” she says. “I thought I was going to die.” The oncoming car smashed into hers, pushing her off the road and into a building with large cement pillars in front. A pillar tore through the car, stopping only about a foot from her face. She was trapped in the crumpled vehicle, but to her shock, she was still alive.

The accident left Magil with two broken ribs and a broken collarbone. It also left her with post-traumatic stress disorder (PTSD) and a desperate wish to forget. Long after her bones healed, Magil was plagued by the memory of the cement barriers looming toward her. “I would be doing regular things—cooking something, shopping, whatever—and the image would just come into my mind from nowhere,” she says. Her heart would pound; she would start to sweat and feel jumpy all over. It felt visceral and real, like something that was happening at that very moment.

Most people who survive accidents or attacks never develop PTSD. But for some, the event forges a memory that is pathologically potent, erupting into consciousness again and again. “PTSD really can be characterized as a disorder of memory,” says McGill University psychologist Alain Brunet, who studies and treats psychological trauma. “It’s about what you wish to forget and what you cannot forget.” This kind of memory is not misty and water­colored. It is relentless.

More than a year after her accident, Magil saw Brunet’s ad for an experimental treatment for PTSD, and she volunteered. She took a low dose of a common blood-pressure drug, propranolol, that reduces activity in the amygdala, a part of the brain that processes emotions. Then she listened to a taped re-creation of her car accident. She had relived that day in her mind a thousand times. The difference this time was that the drug broke the link between her factual memory and her emotional memory. Propranolol blocks the action of adrenaline, so it prevented her from tensing up and getting anxious. By having Magil think about the accident while the drug was in her body, Brunet hoped to permanently change how she remembered the crash. It worked. She did not forget the accident but was actively able to reshape her memory of the event, stripping away the terror while leaving the facts behind.

Brunet’s experiment emerges from one of the most exciting and controversial recent findings in neuroscience: that we alter our memories just by remembering them. Karim Nader of McGill—the scientist who made this discovery—hopes it means that people with PTSD can cure themselves by editing their memories. Altering remembered thoughts might also liberate people imprisoned by anxiety, obsessive-compulsive disorder, even addiction. “There is no such thing as a pharmacological cure in psychiatry,” Brunet says. “But we may be on the verge of changing that.”

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A Scientist’s Guide to Finding Alien Life: Where, When, and in What Universe

[div class=attrib]From Discover:[end-div]

Things were not looking so good for alien life in 1976, after the Viking I spacecraft landed on Mars, stretched out its robotic arm, and gathered up a fist-size pile of red dirt for chemical testing. Results from the probe’s built-in lab were anything but encouraging. There were no clear signs of biological activity, and the pictures Viking beamed back showed a bleak, frozen desert world, backing up that grim assessment. It appeared that our best hope for finding life on another planet had blown away like dust in a Martian windstorm.

What a difference 33 years makes. Back then, Mars seemed the only remotely plausible place beyond Earth where biology could have taken root. Today our conception of life in the universe is being turned on its head as scientists are finding a whole lot of inviting real estate out there. As a result, they are beginning to think not in terms of single places to look for life but in terms of “habitable zones”—maps of the myriad places where living things could conceivably thrive beyond Earth. Such abodes of life may lie on other planets and moons throughout our galaxy, throughout the universe, and even beyond.

The pace of progress is staggering. Just last November new studies of Saturn’s moon Enceladus strengthened the case for a reservoir of warm water buried beneath its craggy surface. Nobody had ever thought of this roughly 300-mile-wide icy satellite as anything special—until the Cassini spacecraft witnessed geysers of water vapor blowing out from its surface. Now Enceladus joins Jupiter’s moon Europa on the growing list of unlikely solar system locales that seem to harbor liquid water and, in principle, the ingredients for life.

Astronomers are also closing in on a possibly huge number of Earth-like worlds around other stars. Since the mid-1990s they have already identified roughly 340 extrasolar planets. Most of these are massive gaseous bodies, but the latest searches are turning up ever-smaller worlds. Two months ago the European satellite Corot spotted an extrasolar planet less than twice the diameter of Earth (see “The Inspiring Boom in Super-Earths”), and NASA’s new Kepler probe is poised to start searching for genuine analogues of Earth later this year. Meanwhile, recent discoveries show that microorganisms are much hardier than we thought, meaning that even planets that are not terribly Earth-like might still be suited to biology.

Together, these findings indicate that Mars was only the first step of the search, not the last. The habitable zones of the cosmos are vast, it seems, and they may be teeming with life.

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The Biocentric Universe Theory: Life Creates Time, Space, and the Cosmos Itself

[div class=attrib]From Discover:[end-div]

The farther we peer into space, the more we realize that the nature of the universe cannot be understood fully by inspecting spiral galaxies or watching distant supernovas. It lies deeper. It involves our very selves.

This insight snapped into focus one day while one of us (Lanza) was walking through the woods. Looking up, he saw a huge golden orb web spider tethered to the overhead boughs. There the creature sat on a single thread, reaching out across its web to detect the vibrations of a trapped insect struggling to escape. The spider surveyed its universe, but everything beyond that gossamer pinwheel was incomprehensible. The human observer seemed as far-off to the spider as telescopic objects seem to us. Yet there was something kindred: We humans, too, lie at the heart of a great web of space and time whose threads are connected according to laws that dwell in our minds.

Is the web possible without the spider? Are space and time physical objects that would continue to exist even if living creatures were removed from the scene?

Figuring out the nature of the real world has obsessed scientists and philosophers for millennia. Three hundred years ago, the Irish empiricist George Berkeley contributed a particularly prescient observation: The only thing we can perceive are our perceptions. In other words, consciousness is the matrix upon which the cosmos is apprehended. Color, sound, temperature, and the like exist only as perceptions in our head, not as absolute essences. In the broadest sense, we cannot be sure of an outside universe at all.

For centuries, scientists regarded Berkeley’s argument as a philosophical sideshow and continued to build physical models based on the assumption of a separate universe “out there” into which we have each individually arrived. These models presume the existence of one essential reality that prevails with us or without us. Yet since the 1920s, quantum physics experiments have routinely shown the opposite: Results do depend on whether anyone is observing. This is perhaps most vividly illustrated by the famous two-slit experiment. When someone watches a subatomic particle or a bit of light pass through the slits, the particle behaves like a bullet, passing through one hole or the other. But if no one observes the particle, it exhibits the behavior of a wave that can inhabit all possibilities—including somehow passing through both holes at the same time.

Some of the greatest physicists have described these results as so confounding they are impossible to comprehend fully, beyond the reach of metaphor, visualization, and language itself. But there is another interpretation that makes them sensible. Instead of assuming a reality that predates life and even creates it, we propose a biocentric picture of reality. From this point of view, life—particularly consciousness—creates the universe, and the universe could not exist without us.

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Evolution by Intelligent Design

[div class=attrib]From Discover:[end-div]

“There are no shortcuts in evolution,” famed Supreme Court justice Louis Brandeis once said. He might have reconsidered those words if he could have foreseen the coming revolution in biotechnology, including the ability to alter genes and manipulate stem cells. These breakthroughs could bring on an age of directed reproduction and evolution in which humans will bypass the incremental process of natural selection and set off on a high-speed genetic course of their own. Here are some of the latest and greatest advances.

Embryos From the Palm of Your Hand
In as little as five years, scientists may be able to create sperm and egg cells from any cell in the body, enabling infertile couples, gay couples, or sterile people to reproduce. The technique could also enable one person to provide both sperm and egg for an offspring—an act of “ultimate incest,” according to a report from the Hinxton Group, an international consortium of scientists and bioethicists whose members include such heavyweights as Ruth Faden, director of the Johns Hopkins Berman Institute of Bioethics, and Peter J. Donovan, a professor of biochemistry at the University of California at Irvine.

The Hinxton Group’s prediction comes in the wake of recent news that scientists at the University of Wisconsin and Kyoto University in Japan have transformed adult human skin cells into pluripotent stem cells, the powerhouse cells that can self-replicate (perhaps indefinitely) and develop into almost any kind of cell in the body. In evolutionary terms, the ability to change one type of cell into others—including a sperm or egg cell, or even an embryo—means that humans can now wrest control of reproduction away from nature, notes Robert Lanza, a scientist at Advanced Cell Technology in Massachusetts. “With this breakthrough we now have a working technology whereby anyone can pass on their genes to a child by using just a few skin cells,” he says.

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Is Quantum Mechanics Controlling Your Thoughts?

[div class=attrib]From Discover:[end-div]

Graham Fleming sits down at an L-shaped lab bench, occupying a footprint about the size of two parking spaces. Alongside him, a couple of off-the-shelf lasers spit out pulses of light just millionths of a billionth of a second long. After snaking through a jagged path of mirrors and lenses, these minus­cule flashes disappear into a smoky black box containing proteins from green sulfur bacteria, which ordinarily obtain their energy and nourishment from the sun. Inside the black box, optics manufactured to billionths-of-a-meter precision detect something extraordinary: Within the bacterial proteins, dancing electrons make seemingly impossible leaps and appear to inhabit multiple places at once.

Peering deep into these proteins, Fleming and his colleagues at the University of California at Berkeley and at Washington University in St. Louis have discovered the driving engine of a key step in photosynthesis, the process by which plants and some microorganisms convert water, carbon dioxide, and sunlight into oxygen and carbohydrates. More efficient by far in its ability to convert energy than any operation devised by man, this cascade helps drive almost all life on earth. Remarkably, photosynthesis appears to derive its ferocious efficiency not from the familiar physical laws that govern the visible world but from the seemingly exotic rules of quantum mechanics, the physics of the subatomic world. Somehow, in every green plant or photosynthetic bacterium, the two disparate realms of physics not only meet but mesh harmoniously. Welcome to the strange new world of quantum biology.

On the face of things, quantum mechanics and the biological sciences do not mix. Biology focuses on larger-scale processes, from molecular interactions between proteins and DNA up to the behavior of organisms as a whole; quantum mechanics describes the often-strange nature of electrons, protons, muons, and quarks—the smallest of the small. Many events in biology are considered straightforward, with one reaction begetting another in a linear, predictable way. By contrast, quantum mechanics is fuzzy because when the world is observed at the subatomic scale, it is apparent that particles are also waves: A dancing electron is both a tangible nugget and an oscillation of energy. (Larger objects also exist in particle and wave form, but the effect is not noticeable in the macroscopic world.)

[div class=attrib]More from theSource here.[end-div]

[div class=attrib]Image courtesy of Dylan Burnette/Olympus Bioscapes Imaging Competition.[end-div]

BigBang

Invisibility Becomes More than Just a Fantasy

[div class=attrib]From Discover:[end-div]

Two years ago a team of engineers amazed the world (Harry Potter fans in particular) by developing the technology needed to make an invisibility cloak. Now researchers are creating laboratory-engineered wonder materials that can conceal objects from almost anything that travels as a wave. That includes light and sound and—at the subatomic level—matter itself. And lest you think that cloaking applies only to the intangible world, 2008 even brought a plan for using cloaking techniques to protect shorelines from giant incoming waves.

Engineer Xiang Zhang, whose University of California at Berkeley lab is behind much of this work, says, “We can design materials that have properties that never exist in nature.”

These engineered substances, known as metamaterials, get their unusual properties from their size and shape, not their chemistry. Because of the way they are composed, they can shuffle waves—be they of light, sound, or water—away from an object. To cloak something, concentric rings of the metamaterial are placed around the object to be concealed. Tiny structures—like loops or cylinders—within the rings divert the incoming waves around the object, preventing both reflection and absorption. The waves meet up again on the other side, appearing just as they would if nothing were there.

The first invisibility cloak, designed by engineers at Duke University and Imperial College London, worked for only a narrow band of microwaves. Xiang and his colleagues created metamaterials that can bend visible light backward—a much greater challenge because visible light waves are so small, under 700 nanometers wide. That meant the engineers had to devise cloaking components only tens of nanometers apart.

[div class=attrib]More from theSource here.[end-div]

BigBang

The LHC Begins Its Search for the “God Particle

[div class=attrib]From Discover:[end-div]

The most astonishing thing about the Large Hadron Collider (LHC), the ring-shaped particle accelerator that revved up for the first time on September 10 in a tunnel near Geneva, is that it ever got built. Twenty-six nations pitched in more than $8 billion to fund the project. Then CERN—the European Organization for Nuclear Research—enlisted the help of 5,000 scientists and engineers to construct a machine of unprecedented size, complexity, and ambition.

Measuring almost 17 miles in circumference, the LHC uses 9,300 superconducting magnets, cooled by liquid helium to 1.9 degrees Kelvin above absolute zero (–271.3º C.), to accelerate two streams of protons in opposite directions. It has detectors as big as apartment buildings to find out what happens when these protons cross paths and collide at 99.999999 percent of the speed of light. Yet roughly the same percentage of the human race has no idea what the LHC’s purpose is. Might it destroy the earth by spawning tiny, ravenous black holes? (Not a chance, physicists say. Collisions more energetic than the ones at the LHC happen naturally all the time, and we are still here.)

In fact, the goal of the LHC is at once simple and grandiose: It was created to discover new particles. One of the most sought of these is the Higgs boson, also known as the God particle because, according to current theory, it endowed all other particles with mass. Or perhaps the LHC will find “supersymmetric” particles, exotic partners to known particles like electrons and quarks. Such a discovery would be a big step toward developing a unified description of the four fundamental forces—the “theory of everything” that would explain all the basic interactions in the universe. As a bonus, some of those supersymmetric particles might turn out to be dark matter, the unseen stuff that seems to hold galaxies together.

[div class=attrib]More from theSource here.[end-div]

[div class=attrib] Image courtesy of Maximillien Brice/CERN.[end-div]

BigBang

A Solar Grand Plan

[div class=attrib]From Scientific American:[end-div]

By 2050 solar power could end U.S. dependence on foreign oil and slash greenhouse gas emissions.

High prices for gasoline and home heating oil are here to stay. The U.S. is at war in the Middle East at least in part to protect its foreign oil interests. And as China, India and other nations rapidly increase their demand for fossil fuels, future fighting over energy looms large. In the meantime, power plants that burn coal, oil and natural gas, as well as vehicles everywhere, continue to pour millions of tons of pollutants and greenhouse gases into the atmosphere annually, threatening the planet.

Well-meaning scientists, engineers, economists and politicians have proposed various steps that could slightly reduce fossil-fuel use and emissions. These steps are not enough. The U.S. needs a bold plan to free itself from fossil fuels. Our analysis convinces us that a massive switch to solar power is the logical answer.

  • A massive switch from coal, oil, natural gas and nuclear power plants to solar power plants could supply 69 percent of the U.S.’s electricity and 35 percent of its total energy by 2050.
  • A vast area of photovoltaic cells would have to be erected in the Southwest. Excess daytime energy would be stored as compressed air in underground caverns to be tapped during nighttime hours.
  • Large solar concentrator power plants would be built as well.
  • A new direct-current power transmission backbone would deliver solar electricity across the country.
  • But $420 billion in subsidies from 2011 to 2050 would be required to fund the infrastructure and make it cost-competitive.

[div class=attrib]More from theSource here.[end-div]

BigBang

The Great Cosmic Roller-Coaster Ride

[div class=attrib]From Scientific American:[end-div]

Could cosmic inflation be a sign that our universe is embedded in a far vaster realm

You might not think that cosmologists could feel claustrophobic in a universe that is 46 billion light-years in radius and filled with sextillions of stars. But one of the emerging themes of 21st-century cosmology is that the known universe, the sum of all we can see, may just be a tiny region in the full extent of space. Various types of parallel universes that make up a grand “multiverse” often arise as side effects of cosmological theories. We have little hope of ever directly observing those other universes, though, because they are either too far away or somehow detached from our own universe.

Some parallel universes, however, could be separate from but still able to interact with ours, in which case we could detect their direct effects. The possibility of these worlds came to cosmologists’ attention by way of string theory, the leading candidate for the foundational laws of nature. Although the eponymous strings of string theory are extremely small, the principles governing their properties also predict new kinds of larger membranelike objects—“branes,” for short. In particular, our universe may be a three-dimensional brane in its own right, living inside a nine-dimensional space. The reshaping of higher-dimensional space and collisions between different universes may have led to some of the features that astronomers observe today.

[div class=attrib]More from theSource here.[end-div]

BigBang

Windows on the Mind

[div class=attrib]From Scientific American:[end-div]

Once scorned as nervous tics, certain tiny, unconscious flicks of the eyes now turn out to underpin much of our ability to see. These movements may even reveal subliminal thoughts.

As you read this, your eyes are rapidly flicking from left to right in small hops, bringing each word sequentially into focus. When you stare at a person’s face, your eyes will similarly dart here and there, resting momentarily on one eye, the other eye, nose, mouth and other features. With a little introspection, you can detect this frequent flexing of your eye muscles as you scan a page, face or scene.

But these large voluntary eye movements, called saccades, turn out to be just a small part of the daily workout your eye muscles get. Your eyes never stop moving, even when they are apparently settled, say, on a person’s nose or a sailboat bobbing on the horizon. When the eyes fixate on something, as they do for 80 percent of your waking hours, they still jump and jiggle imperceptibly in ways that turn out to be essential for seeing. If you could somehow halt these miniature motions while fixing your gaze, a static scene would simply fade from view.

[div class=attrib]More from theSource here.[end-div]