Monday, September 12, 2011
Friday, July 8, 2011
Tuesday, June 21, 2011
Tuesday, May 3, 2011
thick brains
Blame brain cells for lack of focus
Scientists discover a neuronal network that may affect attention abilities
By Laura Sanders
Web edition : 4:58 pm
Easily distracted people can stop blaming their lack of focus on the royal wedding, Facebook feeds and hilarious YouTube videos of honey badgers. Rather, a small network of cells in the back left part of the brain may be the culprit, researchers report in the May 4 Journal of Neuroscience.
Knowing how the brain focuses on what’s important — and filters out noise — may help scientists come up with ways to counteract attention disorders.
“Attention has a huge effect on our lives,” says cognitive neuroscientist Carmel Mevorach of the University of Birmingham in England, who was not involved in the study. “Everything we do — literally, everything we do — is affected by attention.”
In this age of information overload, appropriating attention is a challenge, says study coauthor Ryota Kanai of University College London, and some people are much more susceptible to distractions. Kanai and his colleagues wanted to know if brain differences could explain why some people are easily distracted while others stay focused.
For the study, 145 volunteers filled out a survey called the Cognitive Failures Questionnaire, which asks people to rate how frequently they experience mental lapses such as forgetting what they came to a shop to buy or bumping into people. Volunteers’ answers were used to calculate each person’s overall susceptibility to distraction in everyday life. (Incidentally, scores on the same questionnaire also predict how many car accidents someone has.)
Brain scans revealed a difference between people at the two ends of the “distractibility” spectrum: Easily distracted people had denser tissue in a region called the superior parietal cortex on the left side of the head, signaling that there are more nerve cells there.
“The idea that you can actually ask people to rate their distractibility and that it can lead to a particular place in the brain is quite interesting,” Mevorach says.
The finding that people who have trouble paying attention actually have more brain tissue in that region is somewhat counterintuitive, but bigger isn’t always better. As the brain matures, Kanai says, irrelevant nerve cell connections are pruned, so easily distracted people could be missing some brain refinement important for attention control.
To test whether this brain region actually influenced distraction — and wasn’t just associated with it — Kanai and his colleagues temporarily disrupted brain function there in 15 volunteers using a technique called transcranial magnetic stimulation. In what Kanai calls a “psychologist’s version of Where’s Waldo?” people hunt for a circle and filter out irrelevant details, such as a distracting red diamond. With dampened brain activity in the left superior parietal cortex, people took longer to find the target than when brain activity was not reduced, suggesting that this brain region influences attention. Dampening activity in an unrelated part of the brain didn’t have an effect.
Although the new results are convincing, there is still a lot to learn about how the brain pays attention, says neuroscientist Adam Gazzaley of the University of California, San Francisco. “All of these things are pieces of the puzzle of how a very complicated brain interacts with our environment.”
Sunday, March 27, 2011
past and future entangled?
<p><a href="http://www.physorg.com/news/2011-01-physicists-method-timelike-entanglement.html">Physicists describe method to observe timelike entanglement</a></p>
<p>(PhysOrg.com) -- In "ordinary" quantum entanglement, two particles possess properties that are inherently linked with each other, even though the particles may be spatially separated by a large distance. Now, physicists S. Jay Olson and Timothy C. Ralph from the University of Queensland have shown that it's possible to create entanglement between regions of spacetime that are separated in time but not in space, and then to convert the timelike entanglement into normal spacelike entanglement. They also discuss the possibility of using this timelike entanglement from the quantum vacuum for a process they call "teleportation in time."</p>
Friday, February 11, 2011
Seeing into the Fractal Future
Newly discovered counting patterns explain and elaborate cryptic claims made by the self-taught mathematician Srinivasa Ramanujan in 1919 | February 8, 2011 | 6 For someone who died at the age of 32 the largely self-taught Indian mathematicianSrinivasa Ramanujan left behind an impressive legacy of insights into the theory of numbers—including many claims that he did not support with proof. One of his more enigmatic statements, made nearly a century ago, about counting the number of ways in which a number can be expressed as a sum, has now helped researchers find unexpected fractal structures in the landscape of counting.Mathematics' Nearly Century-Old Partitions Enigma Spawns Fractals Solution
PARTITION PROBLEM: The Mandelbrot set, above, is the most famous fractal of them all, and demonstrates the endlessly repeating patterns of forms in nature. Ono and his colleagues discovered a new class of fractals, one that reveals the endlessly repeating superstructure of partition numbersImage: Wikipedia Commons/Wolfgang Beyer
Ramanujan's statement concerned the deceptively simple concept of partitions—the different ways in which a whole number can be subdivided into smaller numbers. Ken Ono of Emory University and his collaborators have now figured out new ways of counting all possible partitions, and found that the results form fractals—namely, structures in which patterns or shapes repeat identically at multiple different scales. "The fractal theory we've discovered completely answers Ramanujan's enigmatic statement," Ono says. The problems his team cracked were seen as holy grails of number theory, and its solutions may have repercussions throughout mathematics.
One way to think of partitions is to consider how a set of any (indistinguishable) objects can be divided into subsets. For example, if you need to store five boxes in your basement, you can pile them all into a single stack; lay them individually on the floor as five subsets containing one box apiece; put them in one pile, or subset, of three plus one pile of two; and so on—you have a total of 7 options:
5, 1+1+1+1+1, 1+1+1+2, 1+1+3, 1+4, 1+2+2 or 2+3.
Mathematicians express this by saying p(5) = 7, where p is short for partition. For the number 6 there are 11 options: p(6) = 11. As the number n increases, p(n) soon starts to grow very fast, so that for example p(100) = 190,569,292 and p(1,000) is a 32-figure number. (The WolframAlpha knowledge engine calculates partitions for numbers as large as one million.)
The concept is so basic and fundamental that it is central to number theory and pops up in most other fields of math as well. Mathematicians have long known that the sequence of numbers made by the p(n)'s for all values of n is far from being random. Ramanujan and others after him found formulas to predict the value of any p(n) with good approximation, for example. And general "recursive" formulas have long existed to calculate p(n), but they don't speed up calculations very much because to find p(n) you first need to know p(n – 1), p(n – 2) and so on. "That's impractical even with the help of a computer today," Ono says.
A direct formula for calculating the exact value of p(n) could in principle be faster. Another advantage of a direct formula would be the ability to compare values of p(n) for arbitrarily large n's and thus to prove the existence of patterns, such as properties that repeat along an entire infinite sequence.
Ramanujan's original statement, in fact, stemmed from the observation of patterns, such as the fact that p(9) = 30, p(9 + 5) = 135, p(9 + 10) = 490, p(9 + 15) = 1,575 and so on are all divisible by 5. Note that here the n's come at intervals of five units.
Ramanujan posited that this pattern should go on forever, and that similar patterns exist when 5 is replaced by 7 or 11—there are infinite sequences of p(n) that are all divisible by 7 or 11, or, as mathematicians say, in which the "moduli" are 7 or 11.
Then, in nearly oracular tone Ramanujan went on: "There appear to be corresponding properties," he wrote in his 1919 paper, "in which the moduli are powers of 5, 7 or 11...and no simple properties for any moduli involving primes other than these three." (Primes are whole numbers that are only divisible by themselves or by 1.) Thus, for instance, there should be formulas for an infinity of n's separated by 5^3 = 125 units, saying that the corresponding p(n)'s should all be divisible by 125.
In the years since, mathematicians were able to prove the simple cases based on Ramanujan's statement. As to what "no simple properties" could mean, that was anybody's guess—until now.
Working with Jan Hendrik Bruinier of Darmstadt Technical University in Germany, Ono has developed the first exact formula for calculating p(n) for any n. And in a separate paper with Zachary A. Kent, also at Emory, and Amanda Folsom of Yale University, he has identified patterns that probably even Ramanujan could not have dreamed of.
The patterns link certain sequences of p(n) where the n's are separated by powers of any prime number beyond 11. For example, take the next prime up, 13, and the sequence p(6), p(6 + 13), p(6 + 13 + 13) and so on. Ono's formulas link these values with those of p(1,007), p(1,007 + 13^2), p(1007 + 13^2 + 13^2) and so on. The same formulas link the latter sequence with one where the n's come at intervals of 13^3—and so on for larger and larger exponents. (The formulas are slightly more subtle than just saying that the p(n) are multiples of a prime.) Such recurrence is typical of fractal structures such as a Mandelbrot set [see the video above], and is the number theory equivalent of zooming into a fractal, Ono explains.
Ono unveiled the discoveries January 21 at a specially convened symposium at Emory. By that afternoon the news had made waves across the math world, and his in-box had filled with 1,500 e-mails from mathematicians, reporters and "cranks," he says. (Ono, Folsom and Kent posted their proof on the Web site of the American Institute of Mathematics and also submitted it to a journal. The full proof of Ono and Bruinier's new formula is still being written up, Ono says.)
"Ken is a phenomenon," comments George E. Andrews, a partitions expert at The Pennsylvania State University. The new fractal view of partitions, Andrews adds, "provides a superstructure that no one anticipated just a few years ago."
Do Ono et al.'s discoveries have any practical use? Hard to predict, Andrews says. "Often deep understanding of underlying pure mathematics takes awhile to filter into applications." In the past methods developed to understand partitions have later been applied to physics problems such as the theory of the strong nuclear force or the entropy of black holes.
Meanwhile, mathematicians are left to contemplate Ramanujan's mind. Many of his claims, Ono points out, have turned out to be incorrect, but his work still illuminates so much of what number theorists study today. "All of this stuff that we're studying right now for some crazy reason was anticipated by Ramanujan," he says.
"He was a magical genius," Andrews adds, "and the rest of us wish we knew how he was able to see so deeply."
the groupthink of gluons
| February 11, 2011 | 18 In its first six months of operation, the Large Hadron Collider near Geneva has yet to find the Higgs boson, solve the mystery of dark matter or discover hidden dimensions of spacetime. It has, however, uncovered a tantalizing puzzle, one that scientists will take up again when the collider restarts in February following a holiday break. Last summer physicists noticed that some of the particles created by their proton collisions appeared to be synchronizing their flight paths, like flocks of birds. The findings were so bizarre that “we’ve spent all the time since [then] convincing ourselves that what we were see ing was real,” says Guido Tonelli, a spokesperson for CMS, one of two general-purpose experiments at the LHC. The effect is subtle. When proton collisions result in the release of more than 110 new particles, the scientists found, the emerging particles seem to fly in the same direction. The high-energy collisions of protons in the LHC may be uncovering “a new deep internal structure of the initial protons,” says Frank Wilczek of the Massachusetts Institute of Technology, winner of a Nobel Prize for his explanation of the action of gluons. Or the particles may have more interconnections than scientists had realized. “At these higher energies [of the LHC], one is taking a snapshot of the proton with higher spatial and time resolution than ever before,” Wilczek says. When seen with such high resolution, protons, according to a theory developed by Wilczek and his colleagues, consist of a dense medium of gluons—massless particles that act inside the protons and neutrons, controlling the behavior of quarks, the constituents of all protons and neutrons. “It is not implausible,” Wilczek says, “that the gluons in that medium interact and are correlated with one another, and these interactions are passed on to the new particles.” If confirmed by other LHC physicists, the phenomenon would be a fascinating new finding about one of the most common particles in our universe and one scientists thought they understood well.
Saturday, January 1, 2011
Snowflakes under the microscope
Snowflakes under the microscope: "
De la neige au microscope | La boite verte (snowflakes under a microscope) via EMSL. Some of them look like the ruins from an alien city.
Read the Full Story » | More on MAKE » | Comments » |
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Digg this!"
U.S. Bioethics Commission Gives Green Light to Synthetic Biology
U.S. Bioethics Commission Gives Green Light to Synthetic Biology: "
In a report being issued Thursday, the Presidential Commission for the Study of Bioethical Issues says that at present the technology — which involves creating novel organisms through the synthesis and manipulation of DNA — poses few risks because it is still in its infancy…
Click here to read this New York Times article.
Click here
Introducing Word Lens from Quest Visual
Introducing Word Lens from Quest Visual: "
Learn why people are calling Word Lens the magic arrival of the future.
This one minute video is well worth a look…
Click here to view it.
Click here
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