Science NEWS

Various approaches to constructing AI

2011-12-11T17:41:00.000-08:00

Self-Improving Artificial Intelligence

Whole Brain Emulation: The Logical Endpoint of Neuroinformatics?

Time estimation ability predicts mathematical intelligence

2011-12-10T19:10:00.000-08:00

Being good at estimating time can be a useful skill on its own, but it may also indicate higher mathematical intelligence as well, according to a new study published in the Dec. 7 issue of the online journal PLoS ONE.

A test of 202 students, evenly divided between males and females, revealed that those subjects who were better at estimating the durations of a series of short tones were also more likely to correctly answer various mathematical questions relative to their more poorly estimating counterparts.

This correlation was not seen with a general intelligence test, suggesting that time estimation is specifically related to mathematical intelligence.

The authors, led by Peter Kramer of the University of Padua in Italy, conclude that this relationship is likely due to a common reliance on spatial ability. "Encouraging this tendency might help improve mathematical intelligence and satisfy one of modern society's greatest needs", says Dr. Kramer.

Source EurekaAlert!

Swarms of bees could unlock secrets to human brains

2011-12-10T18:59:00.000-08:00

Scientists at the University of Sheffield believe decision making mechanisms in the human brain could mirror how swarms of bees choose new nest sites.

Striking similarities have been found in decision making systems between humans and insects in the past but now researchers believe that bees could teach us about how our brains work.

Experts say the insects even appear to have solved indecision, an often paralysing thought process in humans, with scouts who seek out any honeybees advertising rival nest sites and butt against them with their heads while producing shrill beeping sounds.

Dr James Marshall, of the University of Sheffield's Department of Computer Science, who led the UK involvement in the project and has also previously worked on similarities between how brains and insect colonies make decisions, said: "Up to now we've been asking if honeybee colonies might work in the same way as brains; now the new mathematical modelling we've done makes me think we should be asking whether our brains might work like honeybee colonies.

"Many people know about the waggle dance that honeybees use to direct hive mates to rich flower patches and new nest sites. Our research published in the journal Science (on December 9), shows that this isn't the only way that honeybees communicate with each other when they are choosing a new nest site; they also disrupt the waggle dances of bees that are advertising alternative sites."

Biologists from Cornell University, New York, University of California Riverside and the University of Bristol set up two nest boxes for a homeless honeybee swarm to choose between and recorded how bees that visited each box interacted with bees from the rival box. They found that bees that visited one site, which were marked with pink paint, tended to inhibit the dances of bees advertising the other site, which were marked with yellow paint, and vice versa.

Tom Seeley of Cornell University, author of the best-selling book Honeybee Democracy said "We were amazed to discover that the bees from one nest box would seek out bees performing waggle dances for the other nest box and butt against them with their heads while simultaneously producing shrill beeping sounds. We call this rough treatment the 'stop signal' because most bees that receive this signal will cease dancing a few seconds later."

Dr Patrick Hogan of the University of Sheffield, who constructed the mathematical model of the bees, added: "The bees target their stop signal only at rivals within the colony, preventing the colony as a whole from becoming deadlocked with indecision when choosing a new home. This remarkable behaviour emerges naturally from the very simple interactions observed between the individual bees in the colony."

Source EurekaAlert!

Discovery of the fastest-rotating massive star ever recorded

2011-12-05T23:33:00.000-08:00

(Santa Barbara, Calif.) –– An international team of scientists has found the fastest-rotating massive star ever recorded. The star spins around its axis at the speed of 600 kilometers per second at the equator, a rotational velocity so high that the star is nearly tearing apart due to centrifugal forces. This confirms a prediction put forward by astrophysicist Matteo Cantiello, a postdoctoral fellow with UC Santa Barbara's Kavli Institute for Theoretical Physics, who contributed to the discovery published this week in theAstrophysical Journal Letters.

This is an artist's concept of the fastest-rotating massive star found to date. The massive, bright young star, called VFTS 102, rotates at about two million kilometers per hour. Centrifugal force from this dizzying spin rate has flattened the star into an oblate shape, and spun off a disk of hot plasma, seen edge on in this view from a hypothetical planet. The star may have "spun up" by accreting material from a binary companion star. Scientists believe that the rapidly evolving companion star later exploded as a supernova. The whirling star lies 160,000 light years away in the Large Magellanic Cloud, a satellite galaxy of the Milky Way.

The observations were made at the European Southern Observatory's Very Large Telescope, at the Paranal Observatory in Chile, as part of a survey of the heaviest and brightest stars in a region called the Tarantula Nebula. The Tarantula Nebula is a region of star formation located in a neighboring galaxy called the Large Magellanic Cloud, about 160,000 light years from Earth. The reported star, VFTS 102, is extremely hot and luminous, shining about 100,000 times more brightly than the sun. According to the research team, this star had a violent past and was ejected from a double star system by its exploding companion star.

Cantiello and collaborators explained that stars could reach such rapid rotation via a "cosmic dance" with another star so close that gravity strips gas from its surface. "This gas falls onto the companion star, increasing the mass and spinning it up," said Cantiello. "Similar to a tennis ball spinning fast after being hit by a glancing blow, a star rotates quickly after being hit off-center by the in-falling gas."
Cantiello previously predicted the possibility of observing this type of star. He reported this theoretical finding with Sung-Chul Yoon, Norbert Langer, and Mario Livio in a paper published in 2007 in Astronomy & Astrophysics Letters. This theoretical investigation of stars in binary systems predicted extreme rotational velocities after mass accretion. The observed rotational velocity for the star agrees with this prediction.

The star is unusual not only because it rotates so fast, but also because it is moving away from its neighboring stars at a velocity of about 70,000 miles per hour, or 30 kilometers per second. "Having been part of a binary system could explain this space oddity," said Cantiello. "It has been known for over 40 years that a star in a massive binary system can be shot away from its surroundings when the companion ends its life in a spectacular explosion called a supernova. In our theoretical calculations we noticed that the 'spun-up' star would also be moving from its surroundings at a high rate. It is very exciting to find a star that matches both of these predictions."

The star is located close to a pulsar and a supernova remnant, which may be left over from the companion star that once spun-up the observed star. If confirmed, this would provide additional support for the theoretical explanation put forward by Cantiello and collaborators in 2007.
Cantiello said that this star may produce dramatic fireworks as it dies. Such a rapidly rotating, massive star is believed to be the progenitor of some of the brightest explosions in the universe: gamma-ray bursts. These occur when the star's fast rotation produces powerful jets of light and matter.

Source EurekaAlert!

Smallest habitable world around sun-like star found

2011-12-05T18:06:00.002-08:00

Astronomers have found the smallest planet ever detected in the habitable zone around a star like the sun.

The new planet was found with the Kepler telescope, which searches for signs that a star's light has dimmed because a planet has passed between it and the telescope – an event called a transit.

Kepler-22b is just 2.4 times as wide as Earth(Image: NASA/Ames/JPL-Caltech)

"This discovery supports the growing belief that we live in a universe crowded with life," team member Alan Boss of the Carnegie Institution for Science said in a statement. "Kepler is on the verge of determining the actual abundance of habitable, Earth-like planets in our galaxy."

The planet, named Kepler-22b, lies 600 light years away around a star of the same type (called G) as the sun. It is about 2.4 times as wide as Earth and orbits its star every 290 days, right in the middle of its star's habitable zone, where liquid water can exist on an object's surface.

Transit observations cannot pinpoint its mass, however. Astronomers have used other telescopes to search for signs that the planet's gravitational tugs are causing its host star to wobble, but so far have not detected any wobbles. That means the planet's mass must be less than 36 times that of the Earth.

It is close in size to a class of planets called super-Earths, which are up to about 2 times as wide as Earth. "We have no planet like this in our solar system," says Bill Borucki, Kepler's chief scientist at NASA's Ames Research Center in Moffett Field, California. He announced the find on Monday at the Kepler Science Conference at NASA Ames.

Just right

The allowed mass range means the planet could be rocky and could contain water, Borucki says. Ground-based observations in mid-2012, when the patch of sky where the planet lies is more easily visible, could help astronomers nail down the planet's mass. That will help them identify its composition.

Two previous rocky planet candidates have been found in the habitable zones of their stars, but in both cases the stars were cooler than the sun.

And neither candidate was found right in the middle of its star's "Goldilocks" zone, which could boast the best conditions for hosting life as we know it. Kepler-22b's surface is probably a balmy 22 °C, Borucki said.

Scanning for ET

The Kepler telescope has been staring at more than 150,000 stars between the constellations Cygnus and Lyra for the past 1000 days. The Kepler team has now found more than 2300 candidate exoplanets, about 1000 more than itreported in February. Ten of those span no more than about twice Earth's width.

To confirm a new planet, scientists must observe three of its transits. Mission scientists saw the first transit of Kepler-22b three days after Kepler began collecting data in 2009. The third transit appeared in December 2010. "It's a great gift," Borucki said. "We consider this our Christmas planet."

"It's conceivable that these new planet candidates and their [potential] moons could have life," Borucki said.

The SETI Institute in Mountain View, California, will observe the new candidates with its Allen Telescope Array of radio telescopes in California in the hopes of detecting signals from any extraterrestrial civilisations there, said the institute's Jill Tarter. The array had been offline since April due to budget cuts but restarted observations on Monday after raising funds by partnering with the US air force and crowdsourcing donations.

Source New Scientist

Entangled diamonds blur quantum-classical divide

2011-12-03T18:59:00.000-08:00

Two diamonds as wide as earring studs have been made to share the spooky quantum state known as entanglement. The feat, performed at room temperature, blurs the divide between the classical and quantum worlds, since typically the quantum link has been made with much smaller particles at low temperatures.

One laser pulse entangled two diamonds and the next measured the entanglement

Entanglement is one of the weird aspects of quantum mechanics, where the fates of two or more particles are intertwined – even when they are physically far apart. Electrons, for example, have been entangled, so that changing the quantum spin of one affects the spins of its entangled partners.

Macroscopic objects, on the other hand, are supposed to mind their own business – flipping one coin shouldn't force a neighbouring flipped coin to come up heads.

But that's just what happened with two 3-millimetre-wide diamonds on a lab bench at the University of Oxford. Physicists there led by Ka Chung Lee andMichael Sprague were able to show that the diamonds shared one vibrational state between them.

Other researchers had previously shown quantum effects in a supercooled 0.06-millimetre-long strip of metal, which was set in a state where it wasvibrating and not vibrating at the same time. But quantum effects are fragile. The more atoms an object contains, the more they jostle each other about, destroying the delicate links of entanglement.

Fleeting link

Cooling an object down to fractions of a degree above absolute zero was thought to be the only way to keep atoms from doing violence to each other.

"In our case we said, let's not bother doing that," says Ian Walmsley of Oxford, head of the lab where the diamonds were entangled. "It turns out all you need to do is look on a very short timescale, before all that jostling and mugging around has a chance to destroy the coherence."

The team placed two diamonds in front of an ultrafast laser, which zapped them with a pulse of light that lasted 100 femtoseconds (or 10^-13 seconds).

Every so often, according to the classical physics that describes large objects, one of those photons should set the atoms in one of the diamonds vibrating. That vibration saps some energy from the photon. The less energetic photon would then move on to a detector, and each diamond would be left either vibrating or not vibrating.

But if the diamonds behaved as quantum mechanical objects, they would share one vibrational mode between them. It would be as if both diamonds were both vibrating and not vibrating at the same time. "Quantum mechanics says it's not either/or, it's both/and," Walmsley says. "It's that both/and we've been trying to prove."

Same state

To show that the diamonds were truly entangled, the researchers hit them with a second laser pulse just 350 femtoseconds after the first. The second pulse picked up the energy the first pulse left behind, and reached the detector as an extra-energetic photon.

If the system were classical, the second photon should pick up extra energy only half the time – only if it happened to hit the diamond where the energy was deposited in the first place. But in 200 trillion trials, the team found that the second photon picked up extra energy every time. That means the energy was not localised in one diamond or the other, but that they shared the same vibrational state.

Entangled diamonds could some day find uses in quantum computers, which could use entanglement to carry out many calculations at once.

"To actually realise such a device is still a way off in the future, but conceptually that's feasible," Walmsley says. He notes that the diamonds were entangled for only 7000 femtoseconds, which is not long enough for practical applications.

Quantum limit

The real value of the experiment may be in probing the boundary between quantum mechanics and classical physics. "We think that it is the first time that a room-temperature, solid-state system has been demonstrably put in this entangled quantum state," Walmsley says. "This is an interesting avenue for thinking about how quantum mechanics can emerge into the classical world."

Erika Andersson of Heriot-Watt University in Edinburgh, UK, agrees.

"We want to push and see how far quantum mechanics goes," she says. "The reported work is a major step in trying to push quantum mechanics to its limits, in the sense of showing that larger and larger physical systems can behave according to the 'strange' predictions of quantum mechanics."

Source New Scientist

Study shows medical marijuana laws reduce traffic deaths

2011-11-29T19:49:00.000-08:00

Leads to lower consumption of alcohol

DENVER (Nov. 29, 2011) – A groundbreaking new study shows that laws legalizing medical marijuana have resulted in a nearly nine percent drop in traffic deaths and a five percent reduction in beer sales.

"Our research suggests that the legalization of medical marijuana reduces traffic fatalities through reducing alcohol consumption by young adults," said Daniel Rees, professor of economics at the University of Colorado Denver who co-authored the study with D. Mark Anderson, assistant professor of economics at Montana State University.

The researchers collected data from a variety of sources including the National Survey on Drug Use and Health, the Behavioral Risk Factor Surveillance System, and the Fatality Analysis Reporting System.

The study is the first to examine the relationship between the legalization of medical marijuana and traffic deaths.

"We were astounded by how little is known about the effects of legalizing medical marijuana," Rees said. "We looked into traffic fatalities because there is good data, and the data allow us to test whether alcohol was a factor."

Anderson noted that traffic deaths are significant from a policy standpoint.

"Traffic fatalities are an important outcome from a policy perspective because they represent the leading cause of death among Americans ages five to 34," he said.

The economists analyzed traffic fatalities nationwide, including the 13 states that legalized medical marijuana between 1990 and 2009. In those states, they found evidence that alcohol consumption by 20- through 29-year-olds went down, resulting in fewer deaths on the road.

The economists noted that simulator studies conducted by previous researchers suggest that drivers under the influence of alcohol tend to underestimate how badly their skills are impaired. They drive faster and take more risks. In contrast, these studies show that drivers under the influence of marijuana tend to avoid risks. However, Rees and Anderson cautioned that legalization of medical marijuana may result in fewer traffic deaths because it's typically used in private, while alcohol is often consumed at bars and restaurants.

"I think this is a very timely study given all the medical marijuana laws being passed or under consideration," Anderson said. "These policies have not been research-based thus far and our research shows some of the social effects of these laws. Our results suggest a direct link between marijuana and alcohol consumption."

The study also examined marijuana use in three states that legalized medical marijuana in the mid-2000s, Montana, Rhode Island, and Vermont. Marijuana use by adults increased after legalization in Montana and Rhode Island, but not in Vermont. There was no evidence that marijuana use by minors increased.

Opponents of medical marijuana believe that legalization leads to increased use of marijuana by minors.

According to Rees and Anderson, the majority of registered medical marijuana patients in Arizona and Colorado are male. In Arizona, 75 percent of registered patients are male; in Colorado, 68 percent are male. Many are under the age of 40. For instance, 48 percent of registered patients in Montana are under 40.

"Although we make no policy recommendations, it certainly appears as though medical marijuana laws are making our highways safer," Rees said.

###

The study is entitled, "Medical Marijuana Laws, Traffic Fatalities, and Alcohol Consumption." It can be found at:http://www.iza.org/en/webcontent/personnel/photos/index_html?key=4915

Source: Eureka Alert!

A revolution in knot theory

2011-11-29T19:40:00.001-08:00

Providence, RI--- In the 19th century, Lord Kelvin made the inspired guess that elements are knots in the "ether". Hydrogen would be one kind of knot, oxygen a different kind of knot---and so forth throughout the periodic table of elements. This idea led Peter Guthrie Tait to prepare meticulous and quite beautiful tables of knots, in an effort to elucidate when two knots are truly different. From the point of view of physics, Kelvin and Tait were on the wrong track: the atomic viewpoint soon made the theory of ether obsolete. But from the mathematical viewpoint, a gold mine had been discovered: The branch of mathematics now known as "knot theory" has been burgeoning ever since.

This knot has Gauss code O1U2O3U1O2U3.

In his article "The Combinatorial Revolution in Knot Theory", to appear in the December 2011 issue of the Notices of the AMS,, Sam Nelson describes a novel approach to knot theory that has gained currency in the past several years and the mysterious new knot-like objects discovered in the process.

As sailors have long known, many different kinds of knots are possible; in fact, the variety is infinite. A *mathematical* knot can be imagined as a knotted circle: Think of a pretzel, which is a knotted circle of dough, or a rubber band, which is the "un-knot" because it is not knotted. Mathematicians study the patterns, symmetries, and asymmetries in knots and develop methods for distinguishing when two knots are truly different.

Mathematically, one thinks of the string out of which a knot is formed as being a one-dimensional object, and the knot itself lives in three-dimensional space. Drawings of knots, like the ones done by Tait, are projections of the knot onto a two-dimensional plane. In such drawings, it is customary to draw over-and-under crossings of the string as broken and unbroken lines. If three or more strands of the knot are on top of each other at single point, we can move the strands slightly without changing the knot so that every point on the plane sits below at most two strands of the knot. A planar knot diagram is a picture of a knot, drawn in a two-dimensional plane, in which every point of the diagram represents at most two points in the knot. Planar knot diagrams have long been used in mathematics as a way to represent and study knots.

As Nelson reports in his article, mathematicians have devised various ways to represent the information contained in knot diagrams. One example is the Gauss code, which is a sequence of letters and numbers wherein each crossing in the knot is assigned a number and the letter O or U, depending on whether the crossing goes over or under. The Gauss code for a simple knot might look like this: O1U2O3U1O2U3.

In the mid-1990s, mathematicians discovered something strange. There are Gauss codes for which it is impossible to draw planar knot diagrams but which nevertheless behave like knots in certain ways. In particular, those codes, which Nelson calls *nonplanar Gauss codes*, work perfectly well in certain formulas that are used to investigate properties of knots. Nelson writes: "A planar Gauss code always describes a [knot] in three-space; what kind of thing could a nonplanar Gauss code be describing?" As it turns out, there are "virtual knots" that have legitimate Gauss codes but do not correspond to knots in three-dimensional space. These virtual knots can be investigated by applying combinatorial techniques to knot diagrams.

Just as new horizons opened when people dared to consider what would happen if -1 had a square root---and thereby discovered complex numbers, which have since been thoroughly explored by mathematicians and have become ubiquitous in physics and engineering---mathematicians are finding that the equations they used to investigate regular knots give rise to a whole universe of "generalized knots" that have their own peculiar qualities. Although they seem esoteric at first, these generalized knots turn out to have interpretations as familiar objects in mathematics. "Moreover," Nelson writes, "classical knot theory emerges as a special case of the new generalized knot theory."

###

Related to this subject are an upcoming issue of the Journal of Knot Theory and its Ramifications, devoted to virtual knot theory, and the upcoming Knots in Washington conference at George Washington University, December 2-4, 2011, which will focus on on "Categorification of Knots, Algebras, and Quandles; Quantum Computing".

Courtesy of Eureka Alert!

Is sustainability science really a science? Los Alamos and Indiana University researchers say yes.

2011-11-29T19:01:00.000-08:00

LOS ALAMOS, New Mexico, November 22, 2011—The idea that one can create a field of science out of thin air, just because of societal and policy need, is a bold concept. But for the emerging field of sustainability science, sorting among theoretical and applied scientific disciplines, making sense of potentially divergent theory, practice and policy, the gamble has paid off.

In the current issue of theProceedings of the National Academy of Sciences, scientists from Los Alamos National Laboratory, Santa Fe Institute, and Indiana University analyzed the field’s temporal evolution, geographic distribution, disciplinary composition, and collaboration structure.

"We don’t know if sustainability science will solve the essential problems it seeks to address, but there is a legitimate scientific practice in place now," said Luís Bettencourt of Los Alamos National Laboratory and Santa Fe Institute, first author on the paper, "Evolution and structure of sustainability science.

The team’s work shows that although sustainability science has been growing explosively since the late 1980s, only in the last decade has the field matured into a cohesive area of science. Thanks to the emergence of a giant component of scientific collaboration spanning the globe and an array of diverse traditional disciplines, there is now an integrated scientific field of sustainability science as an unusual, inclusive, and ubiquitous scientific practice.

The researchers used an exhaustive literature search to determine if the field can truly be categorized as a legitimate science, using population modeling and documenting technical papers’ evolution over time, worldwide author distribution, range of sciences involved, and the collaboration structure of the participants. Many of these techniques form the basis of a new science of science, which allows researchers to analyze and predict the development of scientific and technological fields.

The researchers ask, “How has it been changing, and who are its contributors in terms of geographic and disciplinary composition? Most important, is the field fulfilling its ambitious program of generating a new synthesis of social, biological, and applied disciplines, and is it spanning locations that have both the capabilities and needs for its insights?”

Bettencourt said that they concluded that the field is both applied and basic, spanning worldwide institutions, governments, and corporations, but the key is the collaboration network that evolved in about the year 2000. “This has never been done, starting a worldwide scientific field defined mainly by the need for informed global social practice and policy,” Bettencourt said, “but sustainability science shows that it can be done.”

Interactive graphic available: Global collaboration network of sustainability science. The maps show number of authors in cities worldwide (red columns) and their coauthorship networks (green lines). Thicker lines indicate a greater number of collaborations between places. The interactive Google Earth map is available athttp://www.santafe.edu/~bettencourt/sustainability/.
Authors: Luís M. A. Bettencourt, Santa Fe Institute and Los Alamos National Laboratory Theoretical Division; and Jasleen Kaur, Center for Complex Networks and Systems Research, School of Informatics and Computing, Indiana University, Bloomington, Indiana.

About Los Alamos National Laboratory

Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and URS for the Department of Energy's National Nuclear Security Administration.

Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.

LANL news media contacts: Nancy Ambrosiano, (505) 667-0471, nwa@lanl.gov

Curtesy of

Los Alamos National Laboratory NEWS CENTER

Molecules to Medicine: Should pepper spray be put on (clinical) trial?

2011-11-23T18:29:00.000-08:00

Pepper spray is all over the news, following the Occupy Wall Street protests, particularly following the widely disseminated images and videos of protestors being sprayed in NY, Portland, andUCDavis.
Before that, I knew and occasionally used its main ingredient, capsaicin, as a treatment for my patients with shingles, an extremely painful Herpes zoster infection. And I knew about the many of the serious side effects of pepper spray, well-described by Deborah Blum.
Recently though, other questions arose, like “How was this learned?”. So off I went, looking for clinical trials to see what, if anything, had been studied, beyond the individual patient, poison control, and toxicology reports. Here’s what I learned:

There are reports of the efficacy of capsaicin in crowd control, but little regarding trials of exposures. Perhaps this is because pepper spray is regulated by the Environmental Protection Agency, as a pesticide and not by the FDA.

The concentration of capsaicin in bear spray is 1-2%; it is 10-30% in “personal defense sprays.”

While the police might feel reassured by the study, “The effect of oleoresin capsicum “pepper” spray inhalation on respiratory function,” I was not. This study met the “gold standard” of clinical trials, in that it was a “randomized, cross-over controlled trial to assess the effect of Oleoresin capsicum (OC) spray inhalation on respiratory function by itself and combined with restraint.” However, while the OC exposure showed no ill effect, only 34 volunteers were exposed to only 1 sec of Cap-Stun 5.5%OC spray by inhalation “from 5 ft away as they might in the field setting (as recommended by both manufacturer and local police policies).”

By contrast, an ACLU report, “Pepper Spray Update: More Fatalities, More Questions” found, in just two years, 26 deaths after OC spraying, noting that death was more likely if the victim was also restrained. This translated to 1 death per 600 times police used spray. (The cause of death was not firmly linked to the OC). According to the ACLU, “an internal memorandum produced by the largest supplier of pepper spray to the California police and civilian markets” concludes that there may be serious risks with more than a 1 sec spray. A subsequent Department of Justice study examined another 63 deaths after pepper spray during arrests; the spray was felt to be a “contributing factor” in several.

A review in 1996 by the Division of Epidemiology of the NC DHHS and OSHA concluded that exposure to OC spray during police training constituted an unacceptable health risk.

Surveillance into crowd control agents examined reports to the British National Poisons Information Service, finding more late (>6 hour) adverse events than had been previously noted, especially skin reactions (blistering, rashes).

Studies have, understandably, more looked at treatment than at systematically exploring toxic effects of pepper spray. An uncontrolled California Poison Control study of 64 patients with exposure to capsaicin (as spray or topically as a cream) showed benefit with topically applied antacids, especially if applied soon after exposure.

In a randomized clinical trial, 47 subjects were assigned to a placebo, a topical nonsteroidal anti-inflammatory agent, or a topical anesthetic. The only group with significant symptomatic improvement in pain received proparacaine hydrochloride 0.5%–and only 55% had decreased pain with treatment.

Another randomized controlled trial looked at 49 volunteers who were treated with one of five treatment groups(aluminum hydroxide–magnesium hydroxide [Maalox], 2% lidocaine gel, baby shampoo, milk, or water). There was a significant difference in pain with more rapid treatment, but not between the groups.

I was most impressed with the efforts of the Black Cross Health Collective in Portland, Oregon. These activists have been thoughtfully approaching studying treatments for pepper spray exposures with published clinical trial protocols, where each volunteer also serves as their own control. Capsaicin is applied to each arm; a “subject-blinded” treatment is applied to one arm, and differences in pain responses are recorded. I love that they are looking for evidenced based solutions.

So far, antacids have been the most effective.

Suggestions for further study

Pepper spray causes inflammation and swelling—particularly a danger for those with underlying asthma or emphysema. In fact, the Department of Justice report notes that in two of 63 clearly documented deaths, the subjects were asthmatic. If they don’t already, police need to have protocols in place to identify and treat “sprayees” who have these pre-existing conditions that predispose them to serious harm from the spray. This particularly holds true for people also at risk for respiratory compromise from being restrained, on other drugs, or with obesity. The study of restrained healthy volunteers exposed to small amounts of capsaicin is simply not applicable to the general population. Also, given that these compounds appear to have delayed effects, there should be legally required medical monitoring of “sprayees” at regular and frequent intervals for at least 24 hours—by someone competent. (Iraq war veteran Kayvan Sabehgi could easily have died from the lacerated spleen sustained in his beating by police. It was 18 hours before he was taken to the hospital, after the jail’s nurse reportedly only offered him a suppository for his abdominal pain. There is also an, as yet unconfirmed report, of a miscarriage after the Portland, Oregon OWS protest last week).

Unfortunately, there is an urgent need for clinical trials in this area—both retrospective assessments of “sprayees” health outcomes, and prospective randomized trials [like the trial done on subjects' arms] to elucidate the effects of various capsaicin concentrations, carrier solvents and propellents and to identify the most effective treatments for each mixture. Until those can be done, there should be a thorough outcomes registry kept, with standardized data being obtained on all those subsequent to being pepper-sprayed.

Sadly, I’m sure the Black Cross and others in the Occupy Wall Street movement will have too many opportunities to test therapies against painful crowd-control chemicals. Studies will be difficult because the settings are largely uncontrolled and because the sprays have different concentrations of capsaicin, carrier solvents, and propellants.

Until then, there should be a moratorium on the use of pepper spray or other “non-lethal” chemicals by police, except in clearly life-threatening confrontations, due to the high number of associated deaths until the risks are better understood?

Perhaps Kamran Loghman, who helped the FBI weaponize pepper spray, will be dismayed enough at the “inappropriate and improper use of chemical agents” to help the Black Cross develop effective antidotes…One can only hope.

Courtesy of Scientific American guest blogger Judy Stone

EVERYTHING FROM NOTHING - the empty set axiom and construction of numbers in mathematics

2011-11-23T05:15:00.000-08:00

THE mathematicians' version of nothing is the empty set. This is a collection that doesn't actually contain anything, such as my own collection of vintage Rolls-Royces. The empty set may seem a bit feeble, but appearances deceive; it provides a vital building block for the whole of mathematics.

Click on image to enlarge

It all started in the late 1800s. While most mathematicians were busy adding a nice piece of furniture, a new room, even an entire storey to the growing mathematical edifice, a group of worrywarts started to fret about the cellar. Innovations like non-Euclidean geometry and Fourier analysis were all very well - but were the underpinnings sound? To prove they were, a basic idea needed sorting out that no one really understood. Numbers.

Sure, everyone knew how to do sums. Using numbers wasn't the problem. The big question was what they were. You can show someone two sheep, two coins, two albatrosses, two galaxies. But can you show them two?

The symbol "2"? That's a notation, not the number itself. Many cultures use a different symbol. The word "two"? No, for the same reason: in other languages it might be deux or zwei or futatsu. For thousands of years humans had been using numbers to great effect; suddenly a few deep thinkers realised no one had a clue what they were.

An answer emerged from two different lines of thought: mathematical logic, and Fourier analysis, in which a complex waveform describing a function is represented as a combination of simple sine waves. These two areas converged on one idea. Sets.

A set is a collection of mathematical objects - numbers, shapes, functions, networks, whatever. It is defined by listing or characterising its members. "The set with members 2, 4, 6, 8" and "the set of even integers between 1 and 9" both define the same set, which can be written as {2, 4, 6, 8}.

Around 1880 the mathematician Georg Cantor developed an extensive theory of sets. He had been trying to sort out some technical issues in Fourier analysis related to discontinuities - places where the waveform makes sudden jumps. His answer involved the structure of the set of discontinuities. It wasn't the individual discontinuities that mattered, it was the whole class of discontinuities.

How many dwarfs?

One thing led to another. Cantor devised a way to count how many members a set has, by matching it in a one-to-one fashion with a standard set. Suppose, for example, the set is {Doc, Grumpy, Happy, Sleepy, Bashful, Sneezy, Dopey}. To count them we chant "1, 2, 3..." while working along the list: Doc (1), Grumpy (2), Happy (3), Sleepy (4), Bashful (5), Sneezy (6) Dopey (7). Right: seven dwarfs. We can do the same with the days of the week: Monday (1), Tuesday (2), Wednesday (3), Thursday (4), Friday (5), Saturday (6), Sunday (7).

Another mathematician of the time, Gottlob Frege, picked up on Cantor's ideas and thought they could solve the big philosophical problem of numbers. The way to define them, he believed, was through the process of deceptively simple process of counting.

What do we count? A collection of things - a set. How do we count it? By matching the things in the set with a standard set of known size. The next step was simple but devastating: throw away the numbers. You could use the dwarfs to count the days of the week. Just set up the correspondence: Monday (Doc), Tuesday (Grumpy)... Sunday (Dopey). There are Dopey days in the week. It's a perfectly reasonable alternative number system. It doesn't (yet) tell us what a number is, but it gives a way to define "same number". The number of days equals the number of dwarfs, not because both are seven, but because you can match days to dwarfs.

What, then, is a number? Mathematical logicians realised that to define the number 2, you need to construct a standard set which intuitively has two members. To define 3, use a standard set with three numbers, and so on. But which standard sets to use? They have to be unique, and their structure should correspond to the process of counting. This was where the empty set came in and solved the whole thing by itself.

Zero is a number, the basis of our entire number system (see "Zero's convoluted history"). So it ought to count the members of a set. Which set? Well, it has to be a set with no members. These aren't hard to think of: "the set of all honest bankers", perhaps, or "the set of all mice weighing 20 tonnes". There is also a mathematical set with no members: the empty set. It is unique, because all empty sets have exactly the same members: none. Its symbol, introduced in 1939 by a group of mathematicians that went by the pseudonym Nicolas Bourbaki, is ?. Set theory needs ? for the same reason that arithmetic needs 0: things are a lot simpler if you include it. In fact, we can define the number 0 as the empty set.

What about the number 1? Intuitively, we need a set with exactly one member. Something unique. Well, the empty set is unique. So we define 1 to be the set whose only member is the empty set: in symbols, {?}. This is not the same as the empty set, because it has one member, whereas the empty set has none. Agreed, that member happens to be the empty set, but there is one of it. Think of a set as a paper bag containing its members. The empty set is an empty paper bag. The set whose only member is the empty set is a paper bag containing an empty paper bag. Which is different: it's got a bag in it (see diagram).

The key step is to define the number 2. We need a uniquely defined set with two members. So why not use the only two sets we've mentioned so far: ? and {?}? We therefore define 2 to be the set {?, {?}}. Which, thanks to our definitions, is the same as {0, 1}.

Now a pattern emerges. Define 3 as {0, 1, 2}, a set with three members, all of them already defined. Then 4 is {0, 1, 2, 3}, 5 is {0, 1, 2, 3, 4}, and so on. Everything traces back to the empty set: for instance, 3 is {?, {?}, {?, {?}}} and 4 is {?, {?}, {?, {?}}, {?, {?}, {?, {?}}}}. You don't want to see what the number of dwarfs looks like.

The building materials here are abstractions: the empty set and the act of forming a set by listing its members. But the way these sets relate to each other leads to a well-defined construction for the number system, in which each number is a specific set that intuitively has that number of members. The story doesn't stop there. Once you've defined the positive whole numbers, similar set-theoretic trickery defines negative numbers, fractions, real numbers (infinite decimals), complex numbers... all the way to the latest fancy mathematical concept in quantum theory or whatever.

So now you know the dreadful secret of mathematics: it's all based on nothing.

Ian Stewart is emeritus professor of mathematics at the University of Warwick, UK

Cuortesy of New Scientist

Revealed – the capitalist network that runs the world

2011-10-28T17:28:00.001-07:00

AS PROTESTS against financial power sweep the world this week, science may have confirmed the protesters' worst fears. An analysis of the relationships between 43,000 transnational corporations has identified a relatively small group of companies, mainly banks, with disproportionate power over the global economy.

The Occupy Wall Street movement spreads to London (Image: Dave Stock)

The study's assumptions have attracted some criticism, but complex systems analysts contacted by New Scientist say it is a unique effort to untangle control in the global economy. Pushing the analysis further, they say, could help to identify ways of making global capitalism more stable.

The idea that a few bankers control a large chunk of the global economy might not seem like news to New York's Occupy Wall Street movement and protesters elsewhere (see photo). But the study, by a trio of complex systems theorists at the Swiss Federal Institute of Technology in Zurich, is the first to go beyond ideology to empirically identify such a network of power. It combines the mathematics long used to model natural systems with comprehensive corporate data to map ownership among the world's transnational corporations (TNCs).

"Reality is so complex, we must move away from dogma, whether it's conspiracy theories or free-market," says James Glattfelder. "Our analysis is reality-based."

Previous studies have found that a few TNCs own large chunks of the world's economy, but they included only a limited number of companies and omitted indirect ownerships, so could not say how this affected the global economy - whether it made it more or less stable, for instance.

The Zurich team can. From Orbis 2007, a database listing 37 million companies and investors worldwide, they pulled out all 43,060 TNCs and the share ownerships linking them. Then they constructed a model of which companies controlled others through shareholding networks, coupled with each company's operating revenues, to map the structure of economic power.

The work, to be published in PLoS One, revealed a core of 1318 companies with interlocking ownerships (see image). Each of the 1318 had ties to two or more other companies, and on average they were connected to 20. What's more, although they represented 20 per cent of global operating revenues, the 1318 appeared to collectively own through their shares the majority of the world's large blue chip and manufacturing firms - the "real" economy - representing a further 60 per cent of global revenues.

The 1318 transnational corporations that form the core of the economy. Superconnected companies are red, very connected companies are yellow. The size of the dot represents revenue (Image: PLoS One)

When the team further untangled the web of ownership, it found much of it tracked back to a "super-entity" of 147 even more tightly knit companies - all of their ownership was held by other members of the super-entity - that controlled 40 per cent of the total wealth in the network. "In effect, less than 1 per cent of the companies were able to control 40 per cent of the entire network," says Glattfelder. Most were financial institutions. The top 20 included Barclays Bank, JPMorgan Chase & Co, and The Goldman Sachs Group.

John Driffill of the University of London, a macroeconomics expert, says the value of the analysis is not just to see if a small number of people controls the global economy, but rather its insights into economic stability.

Concentration of power is not good or bad in itself, says the Zurich team, but the core's tight interconnections could be. As the world learned in 2008, such networks are unstable. "If one [company] suffers distress," says Glattfelder, "this propagates."

"It's disconcerting to see how connected things really are," agrees George Sugihara of the Scripps Institution of Oceanography in La Jolla, California, a complex systems expert who has advised Deutsche Bank.

Yaneer Bar-Yam, head of the New England Complex Systems Institute (NECSI), warns that the analysis assumes ownership equates to control, which is not always true. Most company shares are held by fund managers who may or may not control what the companies they part-own actually do. The impact of this on the system's behaviour, he says, requires more analysis.

Crucially, by identifying the architecture of global economic power, the analysis could help make it more stable. By finding the vulnerable aspects of the system, economists can suggest measures to prevent future collapses spreading through the entire economy. Glattfelder says we may need global anti-trust rules, which now exist only at national level, to limit over-connection among TNCs. Sugihara says the analysis suggests one possible solution: firms should be taxed for excess interconnectivity to discourage this risk.

One thing won't chime with some of the protesters' claims: the super-entity is unlikely to be the intentional result of a conspiracy to rule the world. "Such structures are common in nature," says Sugihara.

Newcomers to any network connect preferentially to highly connected members. TNCs buy shares in each other for business reasons, not for world domination. If connectedness clusters, so does wealth, says Dan Braha of NECSI: in similar models, money flows towards the most highly connected members. The Zurich study, says Sugihara, "is strong evidence that simple rules governing TNCs give rise spontaneously to highly connected groups". Or as Braha puts it: "The Occupy Wall Street claim that 1 per cent of people have most of the wealth reflects a logical phase of the self-organising economy."

So, the super-entity may not result from conspiracy. The real question, says the Zurich team, is whether it can exert concerted political power. Driffill feels 147 is too many to sustain collusion. Braha suspects they will compete in the market but act together on common interests. Resisting changes to the network structure may be one such common interest.

When this article was first posted, the comment in the final sentence of the paragraph beginning "Crucially, by identifying the architecture of global economic power…" was misattributed.

The top 50 of the 147 superconnected companies

1. Barclays plc
2. Capital Group Companies Inc
3. FMR Corporation
4. AXA
5. State Street Corporation
6. JP Morgan Chase & Co
7. Legal & General Group plc
8. Vanguard Group Inc
9. UBS AG
10. Merrill Lynch & Co Inc
11. Wellington Management Co LLP
12. Deutsche Bank AG
13. Franklin Resources Inc
14. Credit Suisse Group
15. Walton Enterprises LLC
16. Bank of New York Mellon Corp
17. Natixis
18. Goldman Sachs Group Inc
19. T Rowe Price Group Inc
20. Legg Mason Inc
21. Morgan Stanley
22. Mitsubishi UFJ Financial Group Inc
23. Northern Trust Corporation
24. Société Générale
25. Bank of America Corporation
26. Lloyds TSB Group plc
27. Invesco plc
28. Allianz SE 29. TIAA
30. Old Mutual Public Limited Company
31. Aviva plc
32. Schroders plc
33. Dodge & Cox
34. Lehman Brothers Holdings Inc*
35. Sun Life Financial Inc
36. Standard Life plc
37. CNCE
38. Nomura Holdings Inc
39. The Depository Trust Company
40. Massachusetts Mutual Life Insurance
41. ING Groep NV
42. Brandes Investment Partners LP
43. Unicredito Italiano SPA
44. Deposit Insurance Corporation of Japan
45. Vereniging Aegon
46. BNP Paribas
47. Affiliated Managers Group Inc
48. Resona Holdings Inc
49. Capital Group International Inc
50. China Petrochemical Group Company

Source New Scientist

NEUTRINOS FASTER THAN LIGHT. The OPERA presentation.

2011-10-02T18:01:00.000-07:00

Below is the video of the OPERA public seminar which covers the set up and surprising results of their experiments.

The first advertising campaign for non-human primates

2011-06-27T22:34:00.000-07:00

Keith Olwell and Elizabeth Kiehner had an epiphany last year. At a TED talk, the two New York advertising executives learned that captive monkeys understand money, and that when faced with economic games they will behave in similar ways to humans. So if they can cope with money, how would they respond to advertising?

Laurie Santos, the Yale University primatologist who gave the TED talk, studies monkeys as a way of exploring the evolution of the human mind. A partnership was soon born between Santos, and Olwell and Kiehner's company Proton. The resulting monkey ad campaign was unveiled on Saturday at the Cannes Lions Festival, the creative festival for the advertising industry.

Monkey brands

The objective, says Olwell, is to see if advertising can make brown capuchins change their behaviour. The team will create two brands of food – the team is considering making two colours of jello – specifically targeted at brown capuchins, one supported by an ad campaign and the other not.

How do you advertise to monkeys? Easy: create a billboard campaign that hangs outside the monkeys' enclosure.

"The foods will be novel to them and are equally delicious," Olwell says. Brand A will be advertised and brand B will not. After a period of exposure to the campaign, the monkeys will be offered a choice of both brands.

Santos plans to kick off the experimental campaign in the coming weeks. "If they tend toward one and not the other we'll be witnessing preference shifting due to our advertising," Olwell says.

Sex sells

Olwell says that developing a campaign for non-humans threw up some special challenges. "They do not have language or culture and they have very short attention spans," he says. "We really had to strip out any hip and current thinking and get to the absolute core of what is advertising.

"We're used to doing fairly complex and nuanced work. For this exploration we had to constantly ask ourselves, 'Could we be less finessed?'. We wanted the most visceral approaches."

New Scientist has seen the resulting two billboards. We are unable to show them until Santos and her team have completed their study, but we can reveal that its message is most certainly visceral.

One billboard shows a graphic shot of a female monkey with her genitals exposed, alongside the brand A logo. The other shows the alpha male of the capuchin troop associated with brand A.

Olwell expects brand A to be the capuchins' favoured product. "Monkeys have been shown in previous studies to really love photographs of alpha males and shots of genitals, and we think this will drive their purchasing habits."

The team wanted shots for the campaign that were as natural as possible. "After we settled on what they were being sold and that we were going to be doing 'sex sells', we really wanted to make a very direct ad. We wanted to shoot our subjects involved in normal day-to-day life."

Source New Scientist

Biologists discover how yeast cells reverse aging

2011-06-24T22:02:00.000-07:00

The gene they found can double yeast lifespan when turned on late in life.

A whole yeast (Saccharomyces cerevisiae) cell viewed by X-ray microscopy. Inside, the nucleus and a large vacuole (red) are visible.

Human cells have a finite lifespan: They can only divide a certain number of times before they die. However, that lifespan is reset when reproductive cells are formed, which is why the children of a 20-year-old man have the same life expectancy as those of an 80-year-old man.

How that resetting occurs in human cells is not known, but MIT biologists have now found a gene that appears to control this process in yeast. Furthermore, by turning on that gene in aged yeast cells, they were able to double their usual lifespan.

If the human cell lifespan is controlled in a similar way, it could offer a new approach to rejuvenating human cells or creating pluripotent stem cells, says Angelika Amon, professor of biology and senior author of a paper describing the work in the June 24 issue of the journal Science.

“If we can identify which genes reverse aging, we can start engineering ways to express them in normal cells,” says Amon, who is also a member of the David H. Koch Institute for Integrative Cancer Research. Lead author of the paper is Koch Institute postdoc Elçin Ünal.

Rejuvenation

Scientists already knew that aged yeast cells look different from younger cells. (Yeast have a normal lifespan of about 30 cell divisions.) Those age-related changes include accumulation of extra pieces of DNA, clumping of cellular proteins and abnormal structures of the nucleolus (a cluster of proteins and nucleic acids found in the cell nucleus that produce all other proteins in the cell).

However, they weren’t sure which of these physical markers were actually important to the aging process. “Nobody really knows what aging is,” Amon says. “We know all these things happen, but we don’t know what will eventually kill a cell or make it sick.”

When yeast cells reproduce, they undergo a special type of cell division called meiosis, which produces spores. The MIT team found that the signs of cellular aging disappear at the very end of meiosis. “There’s a true rejuvenation going on,” Amon says.

The researchers discovered that a gene called NDT80 is activated at the same time that the rejuvenation occurs. When they turned on this gene in aged cells that were not reproducing, the cells lived twice as long as normal.

“It took an old cell and made it young again,” Amon says.

In aged cells with activated NDT80, the nucleolar damage was the only age-related change that disappeared. That suggests that nucleolar changes are the primary force behind the aging process, Amon says.

The next challenge, says Daniel Gottschling, a member of the Fred Hutchinson Cancer Research Center in Seattle, will be to figure out the cellular mechanisms driving those changes. “Something is going on that we don’t know about,” says Gottschling, who was not involved in this research. “It opens up some new biology, in terms of how lifespan is being reset.”

The protein produced by the NDT80 gene is a transcription factor, meaning that it activates other genes. The MIT researchers are now looking for the genes targeted by NDT80, which likely carry out the rejuvenation process.

Amon and her colleagues are also planning to study NDT80’s effects in the worm C. elegans, and may also investigate the effects of the analogous gene in mice, p63. Humans also have the p63 gene, a close relative of the cancer-protective gene p53 found in the cells that make sperm and eggs.

Source MIT

Humans Guided Evolution of Dog Barks

2011-06-24T21:35:00.000-07:00

It’s a question that tends to arise when a neighborhood mutt sees a cat at 3 a.m., or if you live in an apartment above someone who leaves their small, yapping dog alone all day: Why do dogs bark so much?
Perhaps because humans designed them that way.

“The direct or indirect human artificial selection process made the dog bark as we know,” said Csaba Molnar, formerly an ethologist at Hungary’s Eotvos Lorand University.
Molnar’s work was inspired by a simple but intriguing fact: Barking is common in domesticated dogs, but infrequent if not downright absent in their wild counterparts. Wild dogs yip and squeal and whine, but rarely produce the repetitive acoustic percussion that is barking. Many people had made that observation, but Molnar and his colleagues were the first to rigorously investigate it.

Because anatomical differences between wild and domestic dogs don’t explain the barking gap, Molnar hypothesized a link to their one great difference: Domesticated dogs have spent the last 50,000 years in human company, being intensively bred to fit our requirements.
Evolution over such a relatively short time is difficult to pin down, but Molnar reasoned that if his hypothesis were correct, two facts would need to be true: Barks should contain information about dogs’ internal states or external environment, and humans should be able to interpret them.
To people who know dogs well, this might seem self-evident. But not every intuition is true. As Molnar’s research would show, sheepherders — people understandably certain in their ability to recognize their own own dogs’ voices — actually couldn’t distinguish their dogs’ barks from others.

Molnar tested his propositions in a series of experiments described in various journal papers between 2005 and 2010. The most high-profile, published in 2008 in the journal Animal Cognition, described using a computer program to classify dog barks (.pdf).
At the time, many journalists — including this one — glibly interpreted the study as a halting step towards dog-to-human translation, but its significance was deeper. Molnar’s statistical algorithm showed that dog barks displayed common patterns of acoustic structure. In terms of pitch and repetition and harmonics, one dog’s alarm bark fundamentally resembled another dog’s alarm bark, and so on.
Intriguingly, the algorithm showed the most between-individual variation in barks made by dogs at play. According to Molnar, this is a hint of human pressure at work. People traditionally needed to identify alarm sounds quickly, but sounds of play were relatively unimportant.
By recording barks in various situations — confronting a stranger, at play, and so on — and playing them back to humans, Molnar’s group then showed that people could reliably identify the context in which barks were made. In short, we understand them.

The findings support Molnar’s original hypothesis, though more work is needed. Molnar started to cross-reference a phylogenetic tree of dog breeds with their barking habits, looking for an evolutionary trajectory, but never finished. He had been a student, and his thesis was complete. Unable to get more funding, he’s now a science journalist.
According to Eugene Morton, a zoologist and animal communication expert at the National Zoo, Molnar’s ideas are quite plausible. Morton noted that barking is a very useful type of sound, simple and capable of carrying over long distances. However, it could have been a side effect of humans favoring other, domestication-friendly traits in the wolves from which modern dogs descended.
“Barks are used by juvenile wolves, by pups. It’s neotenic — something derived from a juvenile stage, and kept in adults. That’s probably what we selected for,” said Morton. “We don’t want dogs who are dominant over us. The bark might go along with that breeding for juvenile behavior. Or it could have come with something else we selected, such as a lack of aggression.”

Molnar’s research is now a fascinating footnote waiting to be pushed forward by other researchers. In addition to that phylogenetic tree of barking, Molnar would like to see analyses of relationships between breeds’ bark characteristics and their traditional roles. If, as with the deep frightening rumble of mastiff guards, breeds’ barks tend to fit their jobs, it would further support the notion of human-guided bark evolution.
The ultimate evidence, said Molnar, would be if human knowledge of bark structure could be used to synthesize barks. “If these barks, played to dogs and humans, had the same effects, it would be awesome,” he said.

Source Wired

Salty Plumes Point to Underground Ocean inside Saturn's Moon Enceladus

2011-06-24T21:12:00.000-07:00

A NASA spacecraft that in 2005 discovered watery plumes spewing from the surface of Saturn's icy moon Enceladus has now found compelling evidence that the plumes stem from an underground reservoir of saltwater.

WATERWORKS: Abundant salt grains in the plumes spewing from Enceladus point to a large underground reservoir in the icy moon.

The Cassini probe in 2008 and 2009 flew through a towering plume emanating from the moon's southern polar region and sampled its contents. In an analysis published online June 22 in Nature, a team of researchers reports that the composition of the plume is most easily explained by a sizable subterranean body of water. (Scientific American is part of Nature Publishing Group.) Cassini's instruments were not designed to make such measurements—and in fact the mission was supposed to have ended before the flyby took place—but with a postponed retirement and a few on-the-fly software tweaks the versatile spacecraft was able to get a whiff of the geyserlike ejecta.

The plumes have since their discovery been known to be rich in water vapor, but their origin has remained unsettled. Even in the absence of a liquid reservoir belowground, water vapor could stem from some of Enceladus's abundant ice sublimating directly to vapor in the vacuum of space or from the breakdown of hydrated solids called clathrates.

But whereas a liquid reservoir in contact with the moon's rocky core should contain dissolved salts that would be injected into an upwelling geyser, sublimating ice or decomposing clathrates would be much less efficient at producing a salty plume. Planetary scientist Frank Postberg of Heidelberg University and the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, and his colleagues gathered some support for the saltwater hypothesis in 2009 when they showed that some particles in Saturn's diffuse E ring were salt-rich. The E ring is fed by Enceladus's plumes, so the implication was that the salty grains originated in the icy moon's hypothesized subterranean ocean and were ejected into the ring as a kind of frozen sea spray.

But with salty grains constituting only a small percentage of the E ring particles, the ocean hypothesis was hardly a lock. In the new analysis of Cassini's dives through the plumes Postberg and his co-authors found a much greater salt concentration—almost all the particles near the source of the plumes are salty ices. It now becomes much more difficult to explain Enceladus's eruption without invoking a large underground reservoir. "Over 99 percent of the emitted ice being salt-rich, that makes a much stronger case [for an ocean], and it's not in agreement with ice sublimation," Postberg says. "Now, with 99 percent, we know that it's just not plausible to be coming from a solid." The salt-rich grains are heavy and tend to fall back to the surface, explaining their relative paucity in Saturn's E ring compared with lighter, salt-free particles.

"They got a sniff of these salty ice grains when they flew through the E ring," says planetary scientist Francis Nimmo of the University of California, Santa Cruz, who did not contribute to the new study. "Now that sniff has become—practically everything is salty. It makes the case that these grains are coming from some liquid reservoir kind of inescapable."

The icy moon, just 500 kilometers in diameter, could be one of several moons in the solar system to harbor underground stores of liquid water. Some evidence has hinted at a subterranean ocean for Titan, a much larger Saturnian moon, as well as for Ganymede, Callisto and Europa, three of Jupiter's largest satellites, and for Neptune's moon Triton.

But just what Enceladus's reservoir would look like is somewhat uncertain. The salt content implies a body of water in contact with the moon's rocky core, which Enceladus's density indicates is dozens of kilometers below the surface, but the escaping vapor at the surface points to evaporation at much shallower subterranean depths. One possibility is a series of near-surface misty caverns fed by a saltwater ocean at Enceladus's core. "You have an ocean at depth at the interface of the ice and the rocky core," Postberg says. "But it must be connected with reservoirs that are only a few hundred meters below the surface."

The scale and complexity of that hypothesized plumbing raises some questions. "These 'deep misty caverns' must be truly immense, and connected in complicated ways with the ocean and with the surface," says Nicholas Schneider, a planetary scientist at the University of Colorado at Boulder. The detection of salt in the plumes is indeed consistent with a liquid source, Schneider says, but geophysicists now need to come up with a viable description of a watery internal structure for the satellite. "After all, we're really using the plumes to tell us what's going on inside, and nobody's taken up that challenge," he says. "We're watching what little Enceladus spits up, but that hardly tells us much about the baby's insides!"

Another question is how a tiny, icy satellite like Enceladus could maintain a large body of liquid water. The tidal energy generated by Enceladus's orbit around Saturn provides some heating, but not enough to keep a large amount of water from freezing over billions of years. "The big question that we still don't have answered is: How can an ocean survive for geological time?" Nimmo says. "Most likely the answer is it's not a global ocean at all but more of a regional sea." In other words, Enceladus's tidal heat could be concentrated on the south polar region, allowing for a localized reservoir of liquid there on an otherwise frozen moon.

Perhaps Cassini, which has been exploring Saturn since 2004, will deliver more answers about the mysterious ice world in the coming years. The spacecraft's mission, originally set to end in 2008, has been extended through 2017.

Source Scientific American

Raising the Temperature on Cold-Blooded Dinosaurs

2011-06-24T21:04:00.000-07:00

By studying the chemical composition of dinosaur teeth, scientists have determined that some sauropods had body temperatures as warm as those of mammals.

Robert Eagle, an evolutionary biologist at the California Institute of Technology, and colleagues analyzed 11 dinosaur teeth from sauropods. The researchers report their findings in the current issue of the journal Science.
Camarasaurus, a sauropod found in the United States, could reach a length of 66 feet and weigh up to 15 tons. The researchers estimated its body temperature to be about 96.3 degrees Fahrenheit.
Brachiosaurus, a larger sauropod that could grow to 75 feet and 40 tons, was even warmer, about 100.8 degrees Fahrenheit.

A normal human temperature is about 98.6 degrees Fahrenheit.
“So the first conclusion we could draw from that was that these large dinosaurs didn’t have temperatures as cold as modern crocodiles and alligators,” Dr. Eagle said.
But that does not mean that the dinosaurs had internal thermostats to keep body temperature constant independent of the environment, the way mammals and birds do. For one thing, the dinosaurs must have had “the capacity to retain environmental heat just as a function of being so large,” Dr. Eagle said. And they must have had ways to prevent themselves from overheating, he added.

“They might have had physical adaptations, like an internal air sac system, or they may have been seeking out shade in the hottest part of the day,” he said. Or they may have used their long necks and tails to release heat.
In conducting their studies, the researchers looked at the bonding between two isotopes — carbon-13 and oxygen-18 — in bioapatite, a mineral found in dinosaur teeth.
The number of bonds in the mineral correlates with the animals’ temperatures, Dr. Eagle said.
Last year, his team published a preliminary study in which they similarly determined the temperatures of crocodiles, aquarium sharks and alligators by studying dental enamel.

Source The New York Times

Smarter car algorithm shows radio interference risk

2011-06-24T21:00:00.000-07:00

An experiment at the Massachussetts Institute of Technology has highlighted some of the hidden risks inherent in (supposedly) smart cars that will depend on radio-based Intelligent Transport Systems (ITS) for extra safety on the road.

In an ITS system, in-car computers communicate with each other over vehicle-to-vehicle (V2V) microwave radio links, while the cars also communicate with traffic lights and roadside speed sensors over a vehicle-to-infrastructure (V2I) radio signalling system (the infrastructure transmits information about cars that are too old to have ITS systems fitted). When two cars are approaching a junction and the V2V/V2I speed signals suggest they are going to crash, a warning can be sounded or a software algorithm can choose to make one of the cars brake, for instance.

I tried this out on the Millbrook test track in Bedfordshire, UK, in 2007: speeding towards a junction in a Saab my brakes were automatically applied to allow a speeding Opel to pass in front of me. It was by turns scary and impressive. But if it hadn't worked I'd have been toast.
But MIT engineer Domitilla Del Vecchio says such systems can be over-protective, taking braking action when there is no real threat. "It's tempting to treat every vehicle on the road as an agent that's playing against you," she says in an MIT research brief issued today.

So she and researcher Rajeev Verma set out to design an algorithm that doesn't over-react - and to test it with model vehicles in a lab. Their trick was simple: calculate not speed but acceleration and deceleration as cars approach a junction, allowing a much finer calculation of the risk. In 97 out of 100 circuits, the collision avoidance technology worked fine.

But in three cases, there were two near-misses and one collision. The reason? Nothing to do with the algorithm: it was due to delays in V2V and V2I radio communication. This highlights the risk of depending upon a complex safety system like ITS - especially a radio-based one which could easily be jammed or electromagnetically interfered with because of the wireless technologies which proliferate in our built environment.

There is only so much that researchers can do against a phenomenon as difficult to predict as radio interference.
The takehome message? ITS technology will doubtless do much to improve road safety - but sometimes it won't. It's never going to substitute for driver alertness.

Source New Scientist

Lab yeast make evolutionary leap to multicellularity

2011-06-23T18:06:00.000-07:00

IN JUST a few weeks single-celled yeast have evolved into a multicellular organism, complete with division of labour between cells. This suggests that the evolutionary leap to multicellularity may be a surprisingly small hurdle.

One giant leap for yeastkind

Multicellularity has evolved at least 20 times since life began, but the last time was about 200 million years ago, leaving few clues to the precise sequence of events. To understand the process better, William Ratcliff and colleagues at the University of Minnesota in St Paul set out to evolve multicellularity in a common unicellular lab organism, brewer's yeast.

Their approach was simple: they grew the yeast in a liquid and once each day gently centrifuged each culture, inoculating the next batch with the yeast that settled out on the bottom of each tube. Just as large sand particles settle faster than tiny silt, groups of cells settle faster than single ones, so the team effectively selected for yeast that clumped together.

Sure enough, within 60 days - about 350 generations - every one of their 10 culture lines had evolved a clumped, "snowflake" form. Crucially, the snowflakes formed not from unrelated cells banding together but from cells that remained connected to one another after division, so that all the cells in a snowflake were genetically identical relatives. This relatedness provides the conditions necessary for individual cells to cooperate for the good of the whole snowflake.

"The key step in the evolution of multicellularity is a shift in the level of selection from unicells to groups. Once that occurs, you can consider the clumps to be primitive multicellular organisms," says Ratcliff.

In some ways, the snowflakes do behave as if they are multicellular. They grow bigger by cell division and when the snowflakes reach a certain size a portion breaks off to form a daughter cell. This "life cycle" is much like the juvenile and adult stages of many multicellular organisms.

After a few hundred further generations of selection, the snowflakes also began to show a rudimentary division of labour. As the snowflakes reach their "adult" size, some cells undergo programmed cell death, providing weak points where daughters can break off. This lets the snowflakes make more offspring while leaving the parent large enough to sink quickly to the base of the tube, ensuring its survival. Snowflake lineages exposed to different evolutionary pressures evolved different levels of cell death. Since it is rarely to the advantage of an individual cell to die, this is a clear case of cooperation for the good of the larger organism. This is a key sign that the snowflakes are evolving as a unit, Ratcliff reported last week at a meeting of the Society for the Study of Evolution in Norman, Oklahoma.

Other researchers familiar with the work were generally enthusiastic. "It really seemed to me to have the elements of the unfolding in real time of a major transition," says Ben Kerr, an evolutionary biologist at the University of Washington in Seattle. "The fact that it happened so quickly was really exciting."

Sceptics, however, point out that many yeast strains naturally form colonies, and that their ancestors were multicellular tens or hundreds of millions of years ago. As a result, they may have retained some evolved mechanisms for cell adhesion and programmed cell death, effectively stacking the deck in favour of Ratcliff's experiment.

"I bet that yeast, having once been multicellular, never lost it completely," says Neil Blackstone, an evolutionary biologist at Northern Illinois University in DeKalb. "I don't think if you took something that had never been multicellular you would get it so quickly."

Even so, much of evolution proceeds by co-opting existing traits for new uses - and that's exactly what Ratcliff's yeast do. "I wouldn't expect these things to all pop up de novo, but for the cell to have many of the elements already present for other reasons," says Kerr.

Ratcliff and his colleagues are planning to address that objection head-on, by doing similar experiments with Chlamydomonas, a single-celled alga that has no multicellular ancestors. They are also continuing their yeast experiments to see whether further division of labour will evolve within the snowflakes. Both approaches offer an unprecedented opportunity to bring experimental rigour to the study of one of the most important leaps in our distant evolutionary past.

Source New Scientist

Cause of hereditary blindness discovered

2011-06-22T22:38:00.000-07:00

RUB Medicine: new protein identified.

Initially the occurrence of progressive retinal degeneration - progressive retinal atrophy, in man called retinitis pigmentosa - had been identified in Schapendoes dogs. Retinitis pigmentosa is the most common hereditary disease which causes blindness in humans. The researchers report on their findings, in Human Molecular Genetics.

Genetic test developed Based on the new findings, the researchers from Bochum have developed a genetic test for diagnosis in this breed of dogs that can also be used predictively in breeding. Schapendoes dogs are originally a Dutch breed of herding dog, which is now kept mainly in Holland, Germany, Northern Europe and North America. However, the research results are also potentially significant for people. The scientists are currently investigating whether mutations of the CCDC66 gene could also be responsible for some retinitis pigmentosa patients.

Mouse model: disease progression in months instead of years "Since at the beginning of the work, the importance of the CCDC66 protein in the organism was completely unknown, in collaboration with Dr. Thomas Rülicke (Vienna) and Prof. Dr. Saleh Ibrahim (Lübeck), we developed a mouse model with a defect in the corresponding gene" explained Prof. Epplen. The aim was initially to obtain basic information about the consequences of the CCDC66 deficiency in order to draw conclusions on the physiological function of the protein. "Fortunately, the mice showed exactly the expected defect of slow progressive impaired vision", said Epplen. "Along with Dr. Elisabeth Petrasch-Parwez (RUB) and Prof. Dr. Jan Kremers (Erlangen), we were able to anatomically and functionally study the entire development of the visual defect in the mouse in just a few months, whereas the progress takes years in humans and dogs." In this interdisciplinary project, the researchers have precisely documented and characterised the progress of retinal degeneration. Epplen: "Interestingly, the CCDC66 protein is, for example, only localised in certain structures of the rods".

Studies continue The insights gained from the studies of the working group can now be applied in order to better understand the processes that cause this inherited disorder. The mouse model will be studied further, as the researchers said: "with regard to malfunctions of the brain, but naturally, above all as a prerequisite for future therapeutic trials in retinitis pigmentosa."

Source EurekaAlert!

University of Minnesota engineering researchers discover source for generating 'green' electricity

2011-06-22T22:28:00.001-07:00

University of Minnesota engineering researchers in the College of Science and Engineering have recently discovered a new alloy material that converts heat directly into electricity. This revolutionary energy conversion method is in the early stages of development, but it could have wide-sweeping impact on creating environmentally friendly electricity from waste heat sources.

Researchers say the material could potentially be used to capture waste heat from a car's exhaust that would heat the material and produce electricity for charging the battery in a hybrid car. Other possible future uses include capturing rejected heat from industrial and power plants or temperature differences in the ocean to create electricity. The research team is looking into possible commercialization of the technology.

"This research is very promising because it presents an entirely new method for energy conversion that's never been done before," said University of Minnesota aerospace engineering and mechanics professor Richard James, who led the research team."It's also the ultimate 'green' way to create electricity because it uses waste heat to create electricity with no carbon dioxide."

To create the material, the research team combined elements at the atomic level to create a new multiferroic alloy, Ni45Co5Mn40Sn10. Multiferroic materials combine unusual elastic, magnetic and electric properties. The alloy Ni45Co5Mn40Sn10 achieves multiferroism by undergoing a highly reversible phase transformation where one solid turns into another solid. During this phase transformation the alloy undergoes changes in its magnetic properties that are exploited in the energy conversion device.

During a small-scale demonstration in a University of Minnesota lab, the new material created by the researchers begins as a non-magnetic material, then suddenly becomes strongly magnetic when the temperature is raised a small amount. When this happens, the material absorbs heat and spontaneously produces electricity in a surrounding coil. Some of this heat energy is lost in a process called hysteresis. A critical discovery of the team is a systematic way to minimize hysteresis in phase transformations. The team's research was recently published in the first issue of the new scientific journal Advanced Energy Materials.
Watch a short research video of the new material suddenly become magnetic when heated: http://z.umn.edu/conversionvideo.

In addition to Professor James, other members of the research team include University of Minnesota aerospace engineering and mechanics post-doctoral researchers Vijay Srivastava and Kanwal Bhatti, and Ph.D. student Yintao Song. The team is also working with University of Minnesota chemical engineering and materials science professor Christopher Leighton to create a thin film of the material that could be used, for example, to convert some of the waste heat from computers into electricity.
"This research crosses all boundaries of science and engineering," James said. "It includes engineering, physics, materials, chemistry, mathematics and more. It has required all of us within the university's College of Science and Engineering to work together to think in new ways."

Source EurekaAlert!

Researchers identify components of speech recognition pathway in humans

2011-06-22T22:23:00.000-07:00

Finding suggests speech perception evolved from animals.

Washington, D.C. — Neuroscientists at Georgetown University Medical Center (GUMC) have defined, for the first time, three different processing stages that a human brain needs to identify sounds such as speech — and discovered that they are the same as ones identified in non-human primates.

In the June 22 issue of the Journal of Neuroscience, the researchers say their discovery — made possible with the help of 13 human volunteers who spent time in a functional MRI machine — could potentially offer important insights into what can go wrong when someone has difficulty speaking, which involves hearing voice-generated sounds, or understanding the speech of others.

But more than that, the findings help shed light on the complex, and extraordinarily elegant, workings of the "auditory" human brain, says Josef Rauschecker, PhD, a professor in the departments of physiology/ biophysics and neuroscience and a member of the Georgetown Institute for Cognitive and Computational Sciences at GUMC.

"This is the first time we have been able to identify three discrete brain areas that help people recognize and understand the sounds they are hearing," says Rauschecker. "These sounds, such as speech, are vitally important to humans, and it is critical that we understand how they are processed in the human brain."
Rauschecker and his colleagues at Georgetown have been instrumental in building a unified theory about how the human brain processes speech and language. They have shown that both human and non-human primates process speech along two parallel pathways, each of which run from lower to higher functioning neural regions.

These pathways are dubbed the "what" and "where" streams and are roughly analogous to how the brain processes sight, but in different regions. The "where" stream localizes sound and the "what" pathway identifies the sound.
Both pathways begin with the processing of signals in the auditory cortex, located inside a deep fissure on the side of the brain underneath the temples - the so-called "temporal lobe." Information processed by the "what" pathway then flows forward along the outside of the temporal lobe, and the job of that pathway is to recognize complex auditory signals, which include communication sounds and their meaning (semantics). The "where" pathway is mostly in the parietal lobe, above the temporal lobe, and it processes spatial aspects of a sound — its location and its motion in space — but is also involved in providing feedback during the act of speaking.

Auditory perception - the processing and interpretation of sound information - is tied to anatomical structures; signals move from lower to higher brain regions, Rauschecker says. "Sound as a whole enters the ear canal and is first broken down into single tone frequencies, then higher-up neurons respond only to more complex sounds, including those used in the recognition of speech, as the neural representation of the sound moves through the various brain regions," he says.

In this study, Rauschecker and his colleagues — computational neuroscientist Maximilian Riesenhuber, Ph.D., and Mark Chevillet, a student in the Interdisciplinary Program in Neuroscience — identified the three distinct areas in the "what" pathway in humans that had been seen in non-human primates. Only two had been recognized before in previous human studies.

The first, and most primary, is the "core" which analyzes tones at the basic level of simple frequencies. The second area, the "belt", wraps around the core, and integrates several tones, "like buzz sounds," that lie close to each other, Rauschecker says. The third area, the "parabelt," responds to speech sounds such as vowels, which are essentially complex bursts of multiple frequencies.

Rauschecker is fascinated by the fact that although speech and language are considered to be uniquely human abilities, the emerging picture of brain processing of language suggests "in evolution, language must have emerged from neural mechanisms at least partially available in animals," he says. "There appears to be a conservation of certain processing pathways through evolution in humans and nonhuman primates."

Source EurekaAlert!

Pandora’s Cluster — Clash of the Titans

2011-06-22T20:01:00.000-07:00

A team of scientists studying the galaxy cluster Abell 2744, nicknamed Pandora’s Cluster, have pieced together the cluster’s complex and violent history using telescopes in space and on the ground, including the Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope, the Japanese Subaru telescope, and NASA’s Chandra X-ray Observatory.

The giant galaxy cluster appears to be the result of a simultaneous pile-up of at least four separate, smaller galaxy clusters. The crash took place over a span of 350 million years.

The galaxies in the cluster make up less than 5 percent of its mass. The gas (around 20 percent) is so hot that it shines only in X-rays (colored red in this image). The distribution of invisible dark matter (making up around 75 percent of the cluster’s mass) is colored here in blue.

Dark matter does not emit, absorb, or reflect light, but it makes itself apparent through its gravitational attraction. To pinpoint the location of this elusive substance the team exploited a phenomenon known as gravitational lensing. This is the bending of light rays from distant galaxies as they pass through the gravitational field created by the cluster. The result is a series of telltale distortions in the images of galaxies in the background of the Hubble and VLT observations. By carefully analyzing the way that these images are distorted, it is possible to accurately map where the dark matter lies.

Chandra mapped the distribution of hot gas in the cluster.

The data suggest that the complex collision has separated out some of the hot gas (which interacts upon collision) and the dark matter (which does not) so that they now lie apart from each other, and from the visible galaxies. Near the core of the cluster there is a “bullet” shape where the gas of one cluster collided with that of another to create a shock wave. The dark matter passed through the collision unaffected.

In another part of the cluster, galaxies and dark matter can be found, but no hot gas. The gas may have been stripped away during the collision, leaving behind no more than a faint trail.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

City living affects your brain, researchers find

2011-06-22T19:46:00.000-07:00

The part of the brain that senses danger becomes overactive in city-dwellers when they are under stress.

The brains of people living in cities operate differently from those in rural areas, according to a brain-scanning study. Scientists found that two regions, involved in the regulation of emotion and anxiety, become overactive in city-dwellers when they are stressed and argue that the differences could account for the increased rates of mental health problems seen in urban areas.

Previous research has shown that people living in cities have a 21% increased risk of anxiety disorders and a 39% increased risk of mood disorders. In addition, the incidence of schizophrenia is twice as high in those born and brought up in cities.
In the new study, Professor Andreas Meyer-Lindenberg of the University of Heidelberg in Germany scanned the brains of more than 50 healthy volunteers, who lived in a range of locations from rural areas to large cities, while they were engaged in difficult mental arithmetic tasks. The experiments were designed to make the groups of volunteers feel anxious about their performance.

The results, published in Nature, showed that the amygdala of participants who currently live in cities was over-active during stressful situations. "We know what the amygdala does; it's the danger-sensor of the brain and is therefore linked to anxiety and depression," said Meyer-Lindenberg.
Another region called the cingulate cortex was overactive in participants who were born in cities. "We know [the cingulate cortex] is important for controlling emotion and dealing with environmental adversity."

This excess activity could be at the root of the observed mental health problems, said Meyer-Lindenberg. "We speculate that stress might cause these abnormalities in the first place – that speculation lies outside what we can show in our study, it is primarily based on the fact that this specific brain area is very sensitive to developmental stress. If you stress an animal, you will find even structural abnormalities in that area and those may be enduring and make an animal anxious. What we're proposing is that stress causes these things and stress is where they are expressed and then lead to an increased risk of mental illness."

By 2050, almost 70% of people are predicted to be living in urban areas. On average, city dwellers are "wealthier and receive improved sanitation, nutrition, contraception and healthcare", wrote the researchers in Nature. But urban living is also associated with "increased risk for chronic disorders, a more demanding and stressful social environment and greater social disparities. The biological components of this complex landscape of risk and protective factors remain largely uncharacterised."

In an accompanying commentary in Nature, Dr Daniel Kennedy and Prof Ralph Adolphs, both at the California Institute of Technology, said that there are wide variations in a people's preferences for, and ability to cope with, city life.
"Some thrive in New York city; others would happily swap it for a desert island. Psychologists have found that a substantial factor accounting for this variability is the perceived degree of control that people have over their daily lives. Social threat, lack of control and subordination are all likely candidates for mediating the stressful effects of city life, and probably account for much of the individual differences."

Working out what factors in a city cause the stress in the first place is the next step in trying to understand the mental health effects of urban areas. Meyer-Lindenberg said that social fragmentation, noise or over-crowding might all be factors. "There's prior evidence that if someone invades your personal space, comes too close to you, it's exactly that amygdala-cingulate circuit that gets [switched on] so it could be something as simple as density."

He said the research could be used, in future, to inform city design.
"What we can do is try and make cities better places to live in from the view of mental health. Up to now, there really isn't a lot of evidence-base to tell a city planner what would be good, what would be bad."

Source The Guardian

Icy Saturn Moon May Have Ocean Beneath Its Surface

2011-06-22T19:40:00.000-07:00

Five years ago, scientists discovered that Enceladus, one of Saturn’s moons, had geyserlike plumes spewing water vapor and ice particles.

At least four distinct plumes of water ice spew out from the polar region of Saturn's moon Enceladus.

These plumes originate from a salt-water reservoir, according to a new study published online by the journal Nature.
“We discovered that the plume is stratified in a composition of ice,” said Frank Postberg , an astrophysicist at the University of Heidelberg in Germany. “And the lower you go, the more salt-rich ice grains you find.”
Dr. Postberg and his collaborators analyzed samples of ice particles from the plumes gathered by NASA’s Cassini spacecraft.
The analysis found that salt-rich particles make up more than 99 percent of the solids ejected in Enceladus’s plumes.

The researchers theorize that there are actually two reservoirs connected to the plumes. The first is a salt-water reservoir close to the moon’s surface that is directly feeding the plumes.
But feeding this reservoir, there is likely a larger, deeper salt-water reservoir, Dr. Postberg said.
“We imagine that between the ice and the ice core there is an ocean of depth and this is somehow connected to the surface reservoir,” he said.

Enceladus, Saturn’s sixth moon, is icy and just over 300 miles wide. The presence of water makes it one of a few other places in the solar system where life could exist.
But even if this isn’t the case, it makes life outside of Earth seem more plausible, Dr. Postberg said.
“If there is water in such an unexpected place,” he said, “it leaves possibility for the rest of the universe”.

Source The New York Times

Breaking out of the internet filter bubble

2011-06-22T19:32:00.000-07:00

Eli Pariser is the former executive director of the liberal activism site, MoveOn.org and co-founder of the international political site Avaaz.org. His new book, The Filter Bubble, examines how web personalization is influencing the content we see online. New Scientist caught up with him to talk about the filters he says are shaping our view of the world, and hear why he thinks it's so important to break out of the bubble.

What is the "filter bubble"?
Increasingly we don't all see the same internet. We see stories and ideas and facts that make it through a membrane of personalised algorithms that surround us on Google, Facebook, Yahoo and many other sites. The filter bubble is the personal unique universe of information that results and that we increasingly live in online.

You stumbled upon the filter bubble when you noticed Facebook friends with differing political views were being phased out of your feed, and people were getting very different results for the same search in Google. What made you think all of this was dangerous, or at least harmful?
I take these Facebook dynamics pretty seriously simply because it's a medium that one in 11 people now use. If at a mass level, people don't hear about ideas that are challenging or only hear about ideas that are likeable - as in, you can easily click the "like" button on them - that has fairly significant consequences. I also still have a foot in the social change campaigning world, and I've seen that a campaign about a woman being stoned to death in Iran doesn't get as many likes as a campaign about something more fuzzy and warm.

Do you think part of the problem is that Facebook is still largely used for entertainment?
It's definitely growing very rapidly as a news source. There was a PEW study that said 30 per cent of people under 30 use social media as a news source. I would be surprised if in 15 years surfing news looks like seeking out a bunch of different particular news agencies and seeing what's on their front page.

We have long relied on content filters - in the form publications or TV channels we choose. How is the filter bubble different?
First, yes we've always used filters of some sort, but in this case we don't know we are. We think of the internet as this place where we directly connect with information, but in fact there are these intermediaries, Facebook and Google, that are in the middle in just the same way that editors were in 20th century society. This is invisible; we don't even see or acknowledge that a lot of the time there is filtering at work.
The second issue is that it's passive. We're not choosing a particular editorial viewpoint, and because we're not choosing it, we don't have a sense of on what basis information is being sorted. It's hard to know what's being edited out.
And the final point is that it's a unique universe. It's not like reading a magazine where readers are seeing the same set of articles. Your information environment could differ dramatically from your friends and neighbours and colleagues.

You have suggested that the filter bubble deepens the disconnect between our aspirational selves, who put Citizen Kane high on the movie rental queue, and our actual selves, who really just want to watch The Hangover for the fifth time. Is there a danger inherent in that?
The industry lingo for this is explicit versus revealed preferences. Revealed preferences are what your behaviour suggests you want, and explicit preferences are what you're saying you want. Revealed preferences are in vogue as a way of making decisions for people because now we have the data to do that - to say, you only watched five minutes of Citizen Kane and then turned it off for something else.
But when you take away the possibility of making explicit choices, you're really taking away an enormous amount of control. I choose to do things in my long-term interest even when my short-term behaviour would suggest that it's not what I want to do all the time. I think there's danger in pandering to the short-term self.

What you're promoting has been characterized as a form of "algorithmic paternalism" whereby the algorithm decides what's best for us.
What Facebook does when it selects "like" versus "important" or "recommend" as the name of its button is paternalistic, in the sense that it's making a choice about what kinds of information gets to people on Facebook. It's a very self-serving choice for Facebook, because a medium that only shows you things that people like is a pretty good idea for selling advertising. These systems make value judgments and I think we need to hold them to good values as opposed to merely commercial ones. But, that's not to say that you could take values out of the equation entirely.

Your background is in liberal activism. Do you think the reaction to your ideas as algorithmic paternalism has to do with a perception that you're trying to promote your own political views?
If people think that, they misread me. I'm not suggesting we should go back to a moment where editors impose their values on people whether they want it or not. I'm just saying we can do a better job of drawing information from society at large, if we want to. If Facebook did have an "important" button alongside the "like" button, I have real faith that we would start to promote things that had more social relevance. It's all about how you construct the medium. That's not saying that my ideas of what is important would always trump, it's just that someone's ideas of what is important would rather than nobody's.

You've repeatedly made the case for an "important" button on Facebook, or maybe, as you've put it, an "it was a hard slog at first but in the end it changed my life" button. Do you think really what you're asking Facebook to do is grow up?
Yeah. In its most grandiose rhetoric Facebook wants to be a utility, and if it's a utility, it starts to have more social responsibility. I think Facebook is making this transition, in that it's moved extraordinarily quickly from a feisty insurgent that was cute, fun and new, to being central to lots of people's lives. The generous view is that they're just catching up with the amount of responsibility they've all of a sudden taken on.

Your argument has been called "alarmist", and as I'm sure you're aware, a piece in Slate recently suggested that you're giving these algorithms too much credit. What's your response to such criticism?
There are two things. One is that I'm trying to describe a trend, and I'm trying to make the case that it will continue unless we avert it. I'm not suggesting that it's checkmate already.
Second, there was some great research published in a peer-reviewed internet journal just recently which points out that the effects of personalisation on Google are quite significant: 64 per cent of results are different either in rank or simply different between the users that they tested. That's not a small difference. In fact, in some ways all the results below the first three are mostly irrelevant because people mostly click on the first three results. As Marissa Mayer talked about in an interview, Google actually used to not personalise the first results for precisely this reason. Then, when I called them again, they said, actually we're doing that now. I think that it's moving faster than many people realise.

You offer tips for bursting the filter bubble - deleting cookies, clearing browser history, etc. - but, more broadly, what kind of awareness are you hoping to promote?
I just want people to know that the more you understand how these tools are actually working the more you can use them rather than having them use you.
The other objective here is to highlight the value of the personal data that we're all giving to these companies and to call for more transparency and control when it comes to that data. We're building a whole economy that is premised on the notion that these services are free, but they're really not free. They convert directly into money for these companies, and that should be much more transparent.

Source New Scientist

Quantum magic trick shows reality is what you make it

2011-06-22T19:26:00.000-07:00

Conjurers frequently appear to make balls jump between upturned cups. In quantum systems, where the properties of an object, including its location, can vary depending on how you observe them, such feats should be possible without sleight of hand. Now this startling characteristic has been demonstrated experimentally, using a single photon that exists in three locations at once.

Despite quantum theory's knack for explaining experimental results, some physicists have found its weirdness too much to swallow. Albert Einstein mocked entanglement, a notion at the heart of quantum theory in which the properties of one particle can immediately affect those of another regardless of the distance between them. He argued that some invisible classical physics, known as "hidden-variable theories", must be creating the illusion of what he called "spooky action at a distance".

A series of painstakingly designed experiments has since shown that Einstein was wrong: entanglement is real and no hidden-variable theories can explain its weird effects.

But entanglement is not the only phenomenon separating the quantum from the classical. "There is another shocking fact about quantum reality which is often overlooked," says Aephraim Steinberg of the University of Toronto in Canada.

No absolute reality

In 1967, Simon Kochen and Ernst Specker proved mathematically that even for a single quantum object, where entanglement is not possible, the values that you obtain when you measure its properties depend on the context. So the value of property A, say, depends on whether you chose to measure it with property B, or with property C. In other words, there is no reality independent of the choice of measurement.

It wasn't until 2008, however, that Alexander Klyachko of Bilkent University in Ankara, Turkey, and colleagues devised a feasible test for this prediction. They calculated that if you repeatedly measured five different pairs of properties of a quantum particle that was in a superposition of three states, the results would differ for the quantum system compared with a classical system with hidden variables.

That's because quantum properties are not fixed, but vary depending on the choice of measurements, which skews the statistics. "This was a very clever idea," says Anton Zeilinger of the Institute for Quantum Optics, Quantum Nanophysics and Quantum Information in Vienna, Austria. "The question was how to realise this in an experiment."

Now he, Radek Lapkiewicz and colleagues have realised the idea experimentally. They used photons, each in a superposition in which they simultaneously took three paths. Then they repeated a sequence of five pairs of measurements on various properties of the photons, such as their polarisations, tens of thousands of times.

A beautiful experiment

They found that the resulting statistics could only be explained if the combination of properties that was tested was affecting the value of the property being measured. "There is no sense in assuming that what we do not measure about a system has [an independent] reality," Zeilinger concludes.

Steinberg is impressed: "This is a beautiful experiment." If previous experiments testing entanglement shut the door on hidden variables theories, the latest work seals it tight. "It appears that you can't even conceive of a theory where specific observables would have definite values that are independent of the other things you measure," adds Steinberg.

Kochen, now at Princeton University in New Jersey, is also happy. "Almost a half century after Specker and I proved our theorem, which was based on a [thought] experiment, real experiments now confirm our result," he says.

Niels Bohr, a giant of quantum physics, was a great proponent of the idea that the nature of quantum reality depends on what we choose to measure, a notion that came to be called the Copenhagen interpretation. "This experiment lends more support to the Copenhagen interpretation," says Zeilinger.

Source New Scientist

Red wine's heart health chemical unlocked at last

2011-06-22T19:16:00.000-07:00

FANCY receiving the heart protecting abilities of red wine without having to drink a glass every day? Soon you may be able to, thanks to the synthesis of chemicals derived from resveratrol, the molecule believed to give wine its protective powers. The chemicals have the potential to fight many diseases, including cancer.

Plants make a huge variety of chemicals, called polyphenols, from resveratrol to protect themselves against invaders, particularly fungi. But they only make tiny amounts of each chemical, making it extremely difficult for scientists to isolate and utilise them. The unstable nature of resveratrol has also hindered attempts at building new compounds from the chemical itself.

Scott Snyder at Columbia University in New York and his team have found a way around this: building polyphenols from compounds that resemble, but are subtly different to, resveratrol. These differences make the process much easier. Using these alternative starting materials, they have made dozens of natural polyphenols, including vaticanol C, which is known to kill cancer cells (Nature, DOI: 10.1038/nature10197).

"It's like a recipe book for the whole resveratrol family," says Snyder. "We've opened up a whole casket of nature's goodies."

Source New Scientist

Quantum leap: Magnetic properties of a single proton directly observed for the first time

2011-06-22T02:19:00.000-07:00

Most important milestone in the direct measurement of the magnetic moment of the proton and its anti-particle has been achieved / Focusing the matter-antimatter symmetry.

Researchers at Johannes Gutenberg University Mainz (JGU) and the Helmholtz Institute Mainz (HIM), together with their colleagues from the Max Planck Institute for Nuclear Physics in Heidelberg and the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, have observed spin quantum-jumps with a single trapped proton for the first time. The fact that they have managed to procure this elusive data means that they have overtaken their research competitors at the elite Harvard University and are now the global leaders in this field.

The result is a pioneering step forward in the endeavor to directly measure the magnetic properties of the proton with high precision. The measuring principle is based on the observation of a single proton stored in an electromagnetic particle trap. As it would also be possible to observe an anti-proton using the same method, the prospect that an explanation for the matter-antimatter imbalance in the universe could be found has become a reality. It is essential to be able to analyze antimatter in detail if we are to understand why matter and antimatter did not completely cancel each other out after the Big Bang - in other words, if we are to comprehend how the universe actually came into existence.

The proton has an intrinsic angular momentum or spin, just like other particles. It is like a tiny bar magnet; in this analogy, a spin quantum jump would correspond to a (switch) flip of the magnetic poles. However, detecting the proton spin is a major challenge. While the magnetic moments of the electron and its anti-particle, the positron, were already being measured and compared in the 1980s, this has yet to be achieved in the case of the proton. "We have long been aware of the magnetic moment of the proton, but it has thus far not been observed directly for a single proton but only in the case of particle ensembles," explains Stefan Ulmer, a member of the work group headed by Professor Dr Jochen Walz at the Institute of Physics at the new Helmholtz Institute Mainz.

The real problem is that the magnetic moment of the proton is 660 times smaller than that of the electron, which means that it is considerably harder to detect. It has taken the collaborative research team five years to prepare an experiment that would be precise enough to pass the crucial test. "At last we have successfully demonstrated the detection of the spin direction of a single trapped proton," says an exultant Ulmer, a stipendiary of the International Max Planck Research School for Quantum Dynamics in Heidelberg.

This opens the way for direct high-precision measurements of the magnetic moments of both the proton and the anti-proton. The latter is likely to be undertaken at CERN, the European laboratory for particle physics in Geneva, or at FLAIR/GSI in Darmstadt. The magnetic moment of the anti-proton is currently only known to three decimal places. The method used at the laboratories in Mainz aims at a millionfold improvement of the measuring accuracy and should represent a new highly sensitive test of the matter-antimatter symmetry. This first observation of the spin quantum jumps of a single proton is a crucial milestone in the pursuit of this aim.
Matter-antimatter symmetry is one of the pillars of the Standard Model of elementary particle physics.

According to this model, particles and anti-particles should behave identically once inversions of charge, parity and time - referred to as CPT transformation – are applied simultaneously. High-precision comparisons of the fundamental properties of particles and anti-particles make it possible to accurately determine whether this symmetrical behavior actually occurs, and may provide the basis for theories that extend beyond the Standard Model. Assuming that a difference between the magnetic moments of protons and anti-protons could be detected, this would open up a window on this "new physics".

The results obtained by the Mainz cooperative research team were published online in the leading specialist journal Physical Review Letters on Monday. The article is presented as an "Editor's Suggestion." Furthermore, the American Physical Society (APS) presents the article as "Viewpoint."
The research work carried out by the team of Professor Dr Jochen Walz on anti-hydrogen and the magnetic moment of protons forms part of the "Precision Physics, Fundamental Interactions and Structure of Matter" (PRISMA) Cluster of Excellence, which is currently applying for future sponsorship under the German Federal Excellence Initiative.

Source Johannes Gutenberg Universitat

New test for elusive fundamental particle - anyon - proposed

2011-06-22T02:04:00.000-07:00

In quantum physics there are two classes of fundamental particles. Photons, the quanta of light, are bosons, while the protons and neutrons that make up atomic nuclei belong to the fermions. Bosons and fermions differ in their behavior at a very basic level. This difference is expressed in their quantum statistics. In the 1980s a third species of fundamental particle was postulated, which was dubbed the anyon. In their quantum statistics, anyons interpolate between bosons and fermions.

"They would be a kind of missing link between the two known sorts of fundamental particles," says LMU physicist Dr. Tassilo Keilmann. "According to the laws of quantum physics, anyons must exist – but so far it hasn't been possible to detect them experimentally."

An international team of theorists under Keilmann's leadership has now taken an in-depth look at the question of whether it is possible to create anyons in the context of a realistic experiment. Happily for experimentalists, the answer is yes. The theoreticians have come up with an experimental design in which conventional atoms are trapped in a so-called optical lattice. Based on their calculations, it ought to be possible to manipulate the interactions between atoms in the lattice in such a way as to create and detect anyons. In contrast to the behavior of bosons and fermions, the exotic statistics of anyons should be continuously variable between the endpoints defined by the other two particle types.

"These novel quantum particles should be able to hop between sites in the optical lattice," says Keilmann. "More importantly, they and their quantum statistics should be continuously adjustable during the experiment." In that case, it might even be feasible to transmute bosons into anyons and then to turn these into fermions. Such a transition would be equivalent to a novel "statistically induced quantum phase transition", and would allow the anyons to be used for the construction of quantum computers that would be far more efficient than conventional electronic processors. "We have pointed to the first practical route to the detection of anyons," says Keilmann. "Experimentalists should be able to implement the set-up in the course of experiments that are already underway."

Source EurekaAlert!

Smaller companies hit hardest during emerging market crises

2011-06-22T01:47:00.000-07:00

CORVALLIS, Ore. – A study of the reaction by the United States stock market to international financial crises shows that small companies are often hit hardest, and the impact is above and beyond what would be expected given their exposure to global market factors.

This unexpected result suggests the significant impact that investors’ actions can have during emerging market crises. During these crises, investors flee to the perceived safety of big companies and shed stocks of smaller companies, despite comparable levels of international exposure during normal periods.
“The take-away is, just because you invest locally doesn’t mean you are protected from the global market,” said David Berger, an assistant professor of finance at Oregon State University.

Looking at almost 20 years of data that covered about eight large emerging market crashes, Berger and H.J. Turtle of Washington State University uncovered this flight-from-risk trend on the part of investors that flee from small stocks. The results are published in the current issue of the Global Finance Journal.
“We would expect that stock markets in two different, but related economies would crash at the same time,” Berger said. “But we found that during big market crashes, investors adjust their holdings towards bigger corporate stocks that they perceive as being safer, even after controlling for economic exposures.”

Berger said the results of his study are unexpected because past research has focused on the aggregate U.S. market as a whole and found little impact during emerging market crises.
“Investors see these big blue chip stocks as the safer ones, and small, R&D intensive stocks for example, as riskier,” Berger said. “So the stock of a smaller domestic company could take a hit because of an international shock.”

Berger studies U.S. equity markets and international stocks, and said the findings from this study have important implications for investors, even those who tend to invest mainly in the domestic market.
“Interestingly, larger stocks often benefited from emerging market crises and exhibited positive returns,” Berger added. “Because investors started dumping smaller stocks in favor of safer, larger ones, the irony is that larger multinational corporations potentially see positive benefits during international crises.”

Source Oregon State University

Speaking maths

2011-06-22T01:31:00.000-07:00

We often think of mathematics as a language, but does our brain process mathematical structures in the same way as it processes language? A new study published in the journal Psychological Science suggests that it does: the process of storing and reusing syntax works across different cognitive domains, of which maths and language are just particular examples. Neuroscientists have previously found evidence suggesting a link between maths and language, but according to the authors of the study "this is the first time we've shown it in a behavioral set-up."

The study — conducted by psychologists Christoph Scheepers, Catherine J. Martin, Andriy Myachykov, Kay Teevan, and Izabela Viskupova of the University of Glasgow, and Patrick Sturt of the University of Edinburgh — made use of a cognitive process called structural priming. Simply put, if you use a certain kind of structure in one sentence, you're likely to use it again in a subsequent sentence. To find out how abstract — and cognitively general — this process is, the experimenters gave native English-speaking students a pencil-and-paper test containing a series of maths problems paired with incomplete sentences.

Each maths problem was structured in one of three ways. With high-attachment syntax, the final operation of the problem applied to a large chunk of the earlier part. For instance in the problem 80-(5+15)/5 the final division (by 5) applies to the entire previous addition term (5+15). With low-attachment syntax — say, 80-5+15/5 — the final operation applied to a smaller previous chunk. A third category — baseline problems like 80-5 — implied neither high nor low attachment.

After each equation, the participant was given a fragment of a sentence that they had to complete. Their completed sentence was analysed to see whether the participants had used high or low attachment syntax. For instance the sentence might start with, "The tourist guide mentioned the bells of the church that ...". A high-attachment ending would be "... that chime hourly" as it refers to the entire phrase "the bells of the church". Low attachment would link only the church to the completed final clause — say, "...that stands on a hill."

The subjects were variously successful in solving the problems. Their choice of high or low attachment sentence completions also revealed complexities — some perhaps related to the preference in English for low-attachment syntax.
Still, in significant numbers, high-attachment maths problems primed high-attachment sentence completions, and low-attachment problems made low-attachment completions likely.

What does all this mean? Our cognitive processes operate "at a very high level of abstraction," the authors write. In other words, our ability to deal with syntax isn't specifically linked to language or maths, but sits at a higher level. It may apply in a similar fashion to all kinds of thinking — in numbers, words, or perhaps even music.

Source +Plus Magazine

How dense is a cell?

2011-06-21T18:15:00.000-07:00

Combining an ancient principle with new technology, MIT researchers have devised a way to answer that question.

MIT researchers designed this tiny microfluidic chip that can measure the mass and density of single cells.

More than 2,000 years after Archimedes found a way to determine the density of a king’s crown by measuring its mass in two different fluids, MIT scientists have used the same principle to solve an equally vexing puzzle — how to measure the density of a single cell.

“Density is such a fundamental, basic property of everything,” says William Grover, a research associate in MIT’s Department of Biological Engineering. “Every cell in your body has a density, and if you can measure it accurately enough, it opens a whole new window on the biology of that cell.”

The new method, described in the Proceedings of the National Academy of Sciences the week of June 20, involves measuring the buoyant mass of each cell in two fluids of different densities. Just as measuring the crown’s density helped Archimedes determine whether it was made of pure gold, measuring cell density could allow researchers to gain biophysical insight into fundamental cellular processes such as adaptations for survival, and might also be useful for identifying diseased cells, according to the authors.

Grover and recent MIT PhD recipient Andrea Bryan are lead authors of the paper. Both work in the lab of Scott Manalis, a professor of biological engineering, member of the David H. Koch Institute for Integrative Cancer Research and senior author of the paper.

Going with the flow

Measuring the density of living cells is tricky because it requires a tool that can weigh cells in their native fluid environment, to keep them alive, and a method to measure each cell in two different fluids.

How the lab can determine the weight and density of individual cells.

In 2007, Manalis and his students developed the first technique to measure the buoyant mass of single living cells. Their device, known as a suspended microchannel resonator, pumps cells, in fluid, through a microchannel that runs across a tiny silicon cantilever, or diving-board structure. That cantilever vibrates within a vacuum; when a cell flows through the channel, the frequency of the cantilever’s vibration changes. The cell’s buoyant mass can be calculated from the change in frequency.

To adapt the system to measure density, the researchers needed to flow each cell through the channel twice, each time in a different fluid. A cell’s buoyant mass (its mass as it floats in fluid) depends on its absolute mass and volume, so by measuring two different buoyant masses for a cell, its mass, volume and density can be calculated.

The new device rapidly exchanges the fluids in the channel without harming the cell, and the entire measurement process for one cell takes as little as five seconds.

David Weitz, professor of physics at Harvard University, says the new technique is a clever way of measuring cell density, and opens up many new avenues of research. “The very interesting thing they show is that density seems to have a more sensitive change than some of the more standard measurements. Why is that? I don’t know. But the fact that I don’t know means it’s interesting,” he says.

Changes in density

The researchers tested their system with several types of cells, including red blood cells and leukemia cells. In the leukemia study, the researchers treated the cells with an antibiotic called staurosporine, then measured their density less than an hour later. Even in that short time, a change in density was already apparent. (The cells grew denser as they started to die.) The treated leukemia cells increased their density by only about 1 percent, a change that would be difficult to detect without a highly sensitive device such as this one. Because of that rapid response and sensitivity, this method could become a good way to screen potential cancer drugs.

“It was really easy, by the density measurement, to identify cells that had responded to the drug. If we had looked at mass alone, or volume alone, we never would have seen that effect,” Bryan says.

The researchers also demonstrated that malaria-infected red blood cells lose density as their infection progresses. This density loss was already known, but this is the first time it has been observed in single cells.

Being able to detect changes in red-blood-cell density could also offer a new way to test athletes who try to cheat by “doping” their blood — that is, by removing their own blood and storing it until just before their competition, when it is transfused back into the bloodstream. This boosts the number of red blood cells, potentially enhancing athletic performance.

Storing blood can alter the blood’s physical characteristics, and if those include changes in density, this technique may be able to detect blood doping, Grover says.

Researchers in Manalis’ lab are now investigating the densities of other types of cells, and are starting to work on measuring single cells as they grow over time — specifically cancer cells, which are characterized by uncontrolled growth.

“Understanding how density of individual cancer cells relates to malignant progression could provide fundamental insights into the underlying cellular processes, as well as lead to clinical strategies for treating patients in situations where molecular markers don’t yet exist or are difficult to measure due to limited sample volumes,” Manalis says.

Other authors on the paper are MIT research scientist Monica Diez-Silva; Subra Suresh, former dean of the MIT School of Engineering; and John Higgins of Massachusetts General Hospital and Harvard Medical School.

Source MIT

What Do We Pay Attention To?

2011-06-21T17:58:00.000-07:00

Once we learn the relationship between a cue and its consequences—say, the sound of a bell and the appearance of the white ice cream truck bearing our favorite chocolate cone—do we turn our attention to that bell whenever we hear it? Or do we tuck the information away and marshal our resources to learning other, novel cues—a recorded jingle, or a blue truck?

Psychologists observing “attentional allocation” now agree that the answer is both, and they have arrived at two principles to describe the phenomena. The “predictive” principle says we search for meaningful—important—cues amid the “noise” of our environments. The “uncertainty” principle says we pay most attention to unfamiliar or unpredictable cues, which may yield useful information or surprise us with pleasant or perilous consequences.

Animal studies have supplied evidence for both, and research on humans has showed how predictiveness operates, but not uncertainty. “There was a clear gap in the research,” says Oren Griffiths, a research fellow at the University of New South Wales, in Australia. So he, along with Ameika M. Johnson and Chris J. Mitchell, set out to demonstrate the uncertainty principle in humans.
“We showed that people will pay more attention to a stimulus or a cue if its status as a predictor is unreliable,” he says. The study will be published in an upcoming issue of Psychological Science, a journal of the Association for Psychological Science.

The researchers investigated what is called “negative transfer”—a cognitive process by which a learned association between cue and outcome inhibits any further learning about that cue. We think we know what to expect, so we aren’t paying attention when a different outcome shows up—and we learn that new association more slowly than if the cue or outcome were unpredictable. Negative transfer is a good example of the uncertainty principle at work.

Participants were divided into three groups, and administered the “allergist test.” They observed “Mrs. X” receiving a small piece of fruit—say, apple. Using a scroll bar they predicted her allergic reaction, from none to critical. They then learned that her reaction to the apple was “mild.” Later, when Mrs. X ate the apple, she had a severe reaction which participants also had to learn to predict.

The critical question was how quickly people learned about the severe reaction. Unsurprisingly, if apple was only ever paired with a severe reaction, learning was fast. But what about if apple had previously been shown to be dangerous (i.e. produce a mild allergic reaction)? In this case, learning about the new severe reaction was slow. This is termed the “negative transfer” effect. This effect did not occur, however, when the initial relationship between apple and allergy was uncertain — if, say, apple was sometimes safe to eat. Under these circumstances, the later association between apple and severe allergic reaction was learned rapidly.
Why? “They didn’t know what to expect from the cue, so they had to pay more attention to it,” says Griffiths. “That’s because of the uncertainty principle.”

Source Association for Psychological Science

Putting a new spin on computing

2011-06-21T17:23:00.000-07:00

Physicists at the University of Arizona have achieved a breakthrough toward the development of a new breed of computing devices that can process data using less power.

In a recent publication in Physical Review Letters, physicists at the University of Arizona propose a way to translate the elusive magnetic spin of electrons into easily measurable electric signals. The finding is a key step in the development of computing based on spintronics, which doesn't rely on electron charge to digitize information.
Unlike conventional computing devices, which require electric charges to flow along a circuit, spintronics harnesses the magnetic properties of electrons rather than their electric charge to process and store information.

Just like a magnet with a north and a south pole (left), electrons are surrounded by a magnetic field (right). This magnetic momentum, or spin, could be used to store information in more efficient ways.

"Spintronics has the potential to overcome several shortcomings of conventional, charge-based computing. Microprocessors store information only as long as they are powered up, which is the reason computers take time to boot up and lose any data in their working memory if there is a loss of power," said Philippe Jacquod, an associate professor with joint appointments in the College of Optical Sciences and the department of physics at the College of Science, who published the research together with his postdoctoral assistant, Peter Stano.

"In addition, charge-based microprocessors are leaky, meaning they have to run an electric current all the time just to keep the data in their working memory at their right value," Jacquod added. "That's one reason why laptops get hot while they're working."
"Spintronics avoids this because it treats the electrons as tiny magnets that retain the information they store even when the device is powered down. That might save a lot of energy."
To understand the concept of spintronics, it helps to picture each electron as a tiny magnet, Jacquod explained.

"Every electron has a certain mass, a certain charge and a certain magnetic moment, or as we physicists call it, a spin," he said. "The electron is not physically spinning around, but it has a magnetic north pole and a magnetic south pole. Its spin depends on which pole is pointing up."
Current microprocessors digitize information into bits, or "zeroes" and "ones," determined by the absence or presence of electric charges. "Zero" means very few electronic charges are present; "one" means there are many of them. In spintronics, only the orientation of an electron's magnetic spin determines whether it counts as a zero or a one.

"You want as many magnetic units as possible, but you also want to be able to manipulate them to generate, transfer and exchange information, while making them as small as possible" Jacquod said.
Taking advantage of the magnetic moment of electrons for information processing requires converting their magnetic spin into an electric signal. This is commonly achieved using contacts consisting of common iron magnets or with large magnetic fields. However, iron magnets are too crude to work at the nanoscale of tomorrow's microprocessors, while large magnetic fields disturb the very currents they are supposed to measure.

"Controlling the spin of the electrons is very difficult because it responds very weakly to external magnetic fields," Jacquod explained. "In addition, it is very hard to localize magnetic fields. Both make it hard to miniaturize this technology."
"It would be much better if you could read out the spin by making an electric measurement instead of a magnetic measurement, because miniaturized electric circuits are already widely available," he added.
In their research paper, based on theoretical calculations controlled by numerical simulations, Jacquod and Stano propose a protocol using existing technology and requiring only small magnetic fields to measure the spin of electrons.

"We take advantage of a nanoscale structure known as a quantum point contact, which one can think of as the ultimate bottleneck for electrons," Jacquod explained. "As the electrons are flowing through the circuit, their motion through that bottleneck is constrained by quantum mechanics. Placing a small magnetic field around that constriction allows us to measure the spin of the electrons."

"We can read out the spin of the electrons based on how the current through the bottleneck changes as we vary the magnetic field around it. Looking at how the current changes tells us about the spin of the electrons."
"Our experience tells us that our protocol has a very good chance to work in practice because we have done similar calculations of other phenomena," Jacquod said. "That gives us the confidence in the reliability of these results."

In addition to being able to detect and manipulate the magnetic spin of the electrons, the work is a step forward in terms of quantifying it.
"We can measure the average spin of a flow of electrons passing through the bottleneck," Jacquod explained. "The electrons have different spins, but if there is an excess in one direction, for example ten percent more electrons with an upward spin, we can measure that rather precisely."

He said that up until now, researchers could only determine there was excess, but were not able to quantify it.
"Once you know how to produce the excess spin and know how to measure it, you could start thinking about doing basic computing tasks," he said, adding that in order to transform this work into applications, some distance has yet to be covered.
"We are hopeful that a fundamental stumbling block will very soon be removed from the spintronics roadmap," Stano added.

Spintronics could be a stepping stone for quantum computing, in which an electron not only encodes zero or one, but many intermediate states simultaneously. To achieve this, however, this research should be extended to deal with electrons one-by-one, a feat that has yet to be accomplished.

Source EurekaAlert!

Magnetic Field Sensed by Gene, Study Shows

2011-06-21T17:07:00.000-07:00

A researcher studying how monarch butterflies navigate has picked up a strong hint that people may be able to sense the earth’s magnetic field and use it for orienting themselves.

Many animals rely on the magnetic field for navigation, and researchers have often wondered if people, too, might be able to detect the field; that might explain how Polynesian navigators can make 3,000-mile journeys under starless skies. But after years of inconclusive experiments, interest in people’s possible magnetic sense has waned.

That may change after an experiment being reported Tuesday by Steven M. Reppert, a neurobiologist at the University of Massachusetts Medical School, and his colleagues Lauren E. Foley and Robert J. Gegear. They have been studying cryptochromes, light-sensitive proteins that help regulate the daily rhythm of the body’s cells, and how they help set the sun compass by which monarchs navigate.

But the butterflies can navigate even when the sun is obscured, so they must have a backup system. Since physical chemists had speculated the cryptochromes might be sensitive to magnetism, Dr. Reppert wondered if the monarch butterfly was using its cryptochromes to sense the earth’s magnetic field. He first studied the laboratory fruit fly, whose genes are much easier to manipulate and showed three years ago that the fly could detect magnetic fields but only when its cryptochrome gene was in good working order.
He then showed that the monarch butterfly’s two cryptochrome genes could each substitute for the fly’s gene in letting it sense magnetic fields, indicating that the butterfly uses the proteins for the same purpose.

One of the monarch’s two cryptochrome genes is similar in its DNA sequence to the human cryptochrome gene. That prompted the idea of seeing whether the human gene, too, could restore magnetic sensing to fruit flies whose own gene had been knocked out. In the journal Nature Communications, Dr. Reppert reports that this is indeed the case. “A reassessment of human magnetosensitivity may be in order,” he and his colleagues write.

The human cryptochrome gene is highly active in the eye, raising the possibility that the magnetic field might in some sense be seen, if the cryptochromes interact with the retina.
Dr. Reppert said the focus on human use of the magnetic field for navigation might be misplaced. Following an idea proposed last year by John B. Phillips of Virginia Tech, he said the primary use of magnetic sensing might be for spatial orientation.

“It could be providing a spherical coordinate system that the animal could use for spatial positioning,” he said.
Dr. Phillips said that Dr. Reppert’s work was of interest but that he had been surprised by an experiment in which Dr. Reppert disrupted the part of the cryptochrome thought to interact with the magnetic field, yet the flies had still detected the magnetism. “It’s 50-50 whether he’s really studying what he thinks he is,” Dr. Phillips said.

Dr. Reppert replied that he had already ruled out the alternative explanation suggested by Dr. Phillips.
But both scientists agreed on the possibilities opened up by the cryptochrome system. Depending on how the proteins are aligned in the eye, insects may perceive objects as being lighter or darker as they orient themselves in relation to the magnetic field, Dr. Phillips said.
In fact, the cryptochrome system might supply a grid imposed on all the landmarks in a visual scene, helping a squirrel find a buried acorn, or a fox integrate its visual scene with what it hears. “This is the fun stage where we are not constrained by many facts,” Dr. Phillips said.

If butterflies, birds and foxes possess such a wonderful system, why would it ever have died out in the human lineage? “It may be that our electromagnetic world is interfering with our ability to do this kind of stuff,” Dr. Phillips said.
As for Dr. Reppert, he is now planning his next step, that of understanding how the cryptochrome proteins sense the magnetic field and how they convey that information to the fruit fly’s and monarch’s brain.

Source The New York Times

Largest cosmic structures 'too big' for theories

2011-06-21T16:53:00.000-07:00

Space is festooned with vast "hyperclusters" of galaxies, a new cosmic map suggests. It could mean that gravity or dark energy – or perhaps something completely unknown – is behaving very strangely indeed.

Galaxies, clusters, and superclusters - mere local details?

We know that the universe was smooth just after its birth. Measurements of the cosmic microwave background radiation (CMB), the light emitted 370,000 light years after the big bang, reveal only very slight variations in density from place to place. Gravity then took hold and amplified these variations into today's galaxies and galaxy clusters, which in turn are arranged into big strings and knots called superclusters, with relatively empty voids in between.

On even larger scales, though, cosmological models say that the expansion of the universe should trump the clumping effect of gravity. That means there should be very little structure on scales larger than a few hundred million light years across.

But the universe, it seems, did not get the memo. Shaun Thomas of University College London (UCL), and colleagues have found aggregations of galaxies stretching for more than 3 billion light years. The hyperclusters are not very sharply defined, with only a couple of per cent variation in density from place to place, but even that density contrast is twice what theory predicts.

"This is a challenging result for the standard cosmological models," says Francesco Sylos Labini of the University of Rome, Italy, who was not involved in the work.

Colour guide

The clumpiness emerges from an enormous catalogue of galaxies called the Sloan Digital Sky Survey, compiled with a telescope at Apache Point, New Mexico. The survey plots the 2D positions of galaxies across a quarter of the sky. "Before this survey people were looking at smaller areas," says Thomas. "As you look at more of the sky, you start to see larger structures."

A 2D picture of the sky cannot reveal the true large-scale structure in the universe. To get the full picture, Thomas and his colleagues also used the colour of galaxies recorded in the survey.

More distant galaxies look redder than nearby ones because their light has been stretched to longer wavelengths while travelling through an expanding universe. By selecting a variety of bright, old elliptical galaxies whose natural colour is well known, the team calculated approximate distances to more than 700,000 objects. The upshot is a rough 3D map of one quadrant of the universe, showing the hazy outlines of some enormous structures.

Coagulating dark energy

The result hints at some profound new physical phenomenon, perhaps involving dark energy – the mysterious entity that is accelerating the expansion of space. Dark energy is usually assumed to be uniform across the cosmos. If instead it can pool in some areas, then its repulsive force could push away nearby matter, creating these giant patterns.

Alternatively, we may need to extend our understanding of gravity beyond Einstein's general theory of relativity. "It could be that we need an even more general theory to explain how gravity works on very large scales," says Thomas.

A more mundane answer might yet emerge. Using colour to find distance is very sensitive to observational error, says David Spergel of Princeton University. Dust and stars in our own galaxy could confuse the dataset, for example. Although the UCL team have run some checks for these sources of error, Thomas admits that the result might turn out to be the effect of foreground stars either masking or mimicking distant galaxies.

Fractal structure?

"It will be essential to confirm this with another technique," says Spergel. The best solution would be to get detailed spectra of a large number of galaxies. Researchers would be able to work out their distances from Earth much more precisely, since they would know how much their light has been stretched, or red-shifted, by the expansion of space.

Sylos Labini has made such a map using a subset of Sloan data. It reveals clumpiness on unexpectedly large scales – though not as vast as these. He believes that the universe may have a fractal structure, looking similar at all scales.

A comprehensive catalogue of spectra for Sloan galaxies is being assembled in a project called the Baryon Oscillation Spectroscopic Survey. Meanwhile, the Dark Energy Survey will use a telescope in Chile to measure the colours of even more galaxies than Sloan, beginning in October. Such maps might bring hyperclusters out of the haze – or consign them to the status of monstrous mirage.

Source New Scientist

Universe's highest electric current found

2011-06-21T16:45:00.000-07:00

The main power source for a jet emanating from galaxy 3C303 (red dot at centre of image) is a current of about 10¹⁸ amps (or one "exa-amp")

A COSMIC jet 2 billion light years away is carrying the highest electric current ever seen: 10¹⁸ amps, equivalent to a trillion bolts of lightning.

Philipp Kronberg of the University of Toronto in Canada and colleagues measured the alignment of radio waves around a galaxy called 3C303, which has a giant jet of matter shooting from its core. They saw a sudden change in the waves' alignment coinciding with the jet. "This is an unambiguous signature of a current," says Kronberg.

The team thinks magnetic fields from a colossal black hole at the galaxy's core are generating the current, which is powerful enough to light up the jet and drive it through interstellar gases out to a distance of about 150,000 light years (arxiv.org/abs/1106.1397).

Source New Scientist

Parrots join apes and Aristotle in the club of reason

2011-06-21T16:37:00.000-07:00

Humans do it. Great apes do it. Now a parrot has shown it can use logical reasoning to work out where food is hidden.

Not such a birdbrain.

Sandra Mikolasch of the University of Vienna's Konrad Lorenz Research Station in Austria and her colleagues first checked that seven African grey parrots (Psittacus erithacus) had no preference for the two types of food on offer, seeds or walnuts.

Then each parrot watched a researcher hide a walnut under one opaque cup and a seed under another. Next the researcher hid the cups behind a screen, removed one of the treats and showed the bird which one had been taken. Finally, the screen was removed to see if the parrot could work out which treat must remain, and under which cup it must be.

Only one of the parrots, a female called Awisa, was able to do this, choosing correctly in three-quarters of the tests – 23 out of 30. "So far, only great apes have been shown to master this task," says Mikolasch. As with the parrots, only some apes could solve the problem, she says. "So we now know that a grey parrot is able to logically exclude one possibility in favour of another to get a reward, known as 'inference by exclusion'."

The other parrots chose more randomly, suggesting they hadn't worked out what was going on. But they did show their mettle in easier tests, where the cups were in view throughout.

Source New Scientist

Brain has two slots for working memory

2011-06-21T02:18:00.000-07:00

Mental version of RAM has an independent module in each hemisphere.

Like side-by-side computer RAM cards, the left and the right hemispheres of the brain store information separately, a new study finds. The results help explain why people can remember only a handful of objects at one time, and suggest that people may be able to maximize their cognitive power by delivering information in equal doses to both sides of the brain, researchers suggest online the week of June 20 in the Proceedings of the National Academy of Sciences.

On average, people can hold about four things in their working memory at once, such as the location of four cards in a game of Concentration. Though many studies have linked this memory capacity to intelligence, scientists still don’t completely understand how the brain reaches this limit.
“Why can’t you think about 100 things simultaneously, or 50 things simultaneously? Why only four?” says study coauthor Earl Miller of MIT. “If we understand something about that, we’ll understand something very deep about how the brain represents information and how thoughts are made conscious.”

Miller and his colleagues tested two monkeys (monkeys also have a four-item working memory capacity) in a simple task. First, the monkeys saw two to five colored squares flash on a computer screen for a little less than a second. The screen went blank for about the same amount of time, and then the squares reappeared — but one was a different color. The monkeys were rewarded for spotting the change.
As the number of squares increased, the monkeys got worse at finding the color change. But Miller and his colleagues noticed a curious twist to this limit: Adding an extra square to the left side of the computer screen didn’t affect a monkey’s ability to remember squares on the right side of the screen, and vice versa. The two hemispheres were operating independently.

Each side of the brain handles visual information coming in from the opposite side. Since the monkeys could track about two objects on each side of the screen, this means the magic number of four is really a sum: two objects tracked by the left brain hemisphere and two objects tracked by the right hemisphere.
While the monkeys were doing the tasks, the researchers also eavesdropped on their nerve cell activity using electrodes. Certain changes in the nerve cell behavior told researchers when and where the monkeys’ brains were overloaded, and even which specific squares were causing trouble.
The electrodes showed a distinctive split in working memory performance. Packing one side of the screen with squares caused nerve cells to go haywire. But adding even more squares to the more sparsely populated side of the screen made little difference.

This split-brain finding may lead to techniques for boosting working memory capacity, Miller says. For instance, dashboard information projected evenly onto the left and right sides of a car’s windshield might be more effective than a display confined to one side of the driver’s visual field. Or, Miller suggests, security personnel screening bags at an airport might be more efficient if the X-ray displays scrolled vertically rather than horizontally, since objects moving sideways squander the individual powers of the two hemispheres.

Figuring out how the brain handles objects is important because working memory ability reflects the cognitive power that is measured by IQ scores, SAT scores and the ability to learn a second language, says neuroscientist Edward Vogel of the University of Oregon in Eugene. “The more we understand about these basic capacity limits, the more that’s going to tell us something deep about the core cognitive abilities that differ from individual to individual.”

Source Science News

Human evolution: the long, winding road to modern man

2011-06-21T02:07:00.000-07:00

Professor Chris Stringer tells how conflicting theories and new discoveries have shaped our understanding of humanity's past – and of how narrow the line is between survival and failure.

Chris Stringer, head of human origins at the Natural History Museum.

Our species' origins have been a source of fascination for millennia and account for the huge range of creation myths that are recorded in different cultures. Linnaeus, that great classifier of living things, gave us our biological name Homo sapiens (meaning "wise man") and our high rounded skulls certainly make us distinctive, as do our small brow ridges and chins. However, we are also remarkable for our language, art and complex technology.

The question is: where did these features evolve? Where can humanity place its homeland? In terms of our earliest ancestors, the answer is generally agreed to be Africa. It was here that our first ape-like ancestors began to make their homes on the savannah. However, a fierce debate has continued about whether it was also the ultimate birthplace of our own species.
Forty years ago, no one believed that modern humans could have originated in Africa. In some cases this idea was based on fading racist agendas. For example, in 1962, the American anthropologist Carleton Coon claimed that "If Africa was the cradle of mankind, it was only an indifferent kindergarten. Europe and Asia were our principal schools."

Part of the confusion was due to the lack of well-dated fossil and archaeological evidence. In the intervening years, however, I have been privileged to be involved in helping to accumulate data – fossil, chronological, archaeological and genetic – that show our species did have a recent African origin. But as the latest evidence shows, this origin was complex and in my new book, The Origin of Our Species, I try to make it clear what it means to be human and change perceptions about our origins.

I had been fascinated by ancient humans called Neanderthals even as a 10-year-old, and in 1971, as a 23-year-old student, I left London on a four-month research trip to museums and institutes in 10 European countries to gather data on the shapes of skulls of Neanderthals and of their modern-looking successors in Europe, the Cro-Magnons. My purpose was to test the then popular theory which held that Neanderthals and people like them in each region of the ancient world were the ancestors of people in those same regions today. I had only a modest grant, and so I drove my old car, sleeping in it, camping or staying in youth hostels – in Belgium I even spent one night in a shelter for the homeless. I survived border confrontations and two robberies, but by the end of my 5,000-mile trip I had collected one of the largest data sets of Neanderthal and early modern skull measurements assembled up to that time.

Over the next three years I added data on other ancient and modern samples, and the results were clear: Neanderthals had evolved their own special characteristics, and did not look like ancestors for the Cro-Magnons or for any modern people. The issue was: where had our species evolved? In 1974 I was unable to say, but taking up a research post at the Natural History Museum meant I could continue the quest.
My research uncovered clues, however, and over the next decade my work – along with that of a few others – focused on Africa as the most likely homeland of our species. We remained an isolated minority until 1987, when the paper "Mitochondrial DNA and Human Evolution", was published by Rebecca Cann, Mark Stoneking and Allan Wilson. It put modern human origins on the front pages of newspapers all over the world for the first time for it showed that a tiny and peculiar part of our genome, inherited only through mothers and daughters, derived from an African ancestor about 200,000 years ago. This woman became known as Mitochondrial Eve. A furore followed, as anthropologists rowed over the implications for human evolution.

After that, the "out of Africa" theory – or as I prefer to call it "the recent African origin" model for our origins – really took off. My version depicted the following background. The ancient species Homo erectus survived in East Asia and Indonesia but evolved into Homo heidelbergensis in Europe and Africa. (This last species had been named from a 600,000-year-old jawbone found in Germany in 1907.) Then, about 400,000 years ago, H. heidelbergensis underwent an evolutionary split: north of the Mediterranean it developed into the Neanderthals, while to the south, in Africa, it became us, modern humans. Finally, about 60,000 years ago Homo sapiens began to leave Africa and by 40,000 years ago, with the advantages of more complex tools and behaviours, spread into Asia and Europe, where we replaced the Neanderthals and all the other archaic people outside of Africa. In other words, under our skins, we are all Africans.

Not every scientist agreed, however. One group continued to support the idea of multiregional evolution, an updated version of ideas from the 1930s. It envisaged deep parallel lines of evolution in each inhabited region of Africa, Europe, Asia and Australasia, stretching from local variants of H. erectus right through to living people in the same areas today. These lines did not diverge through time, since they were glued together by interbreeding across the ancient world, so modern features could gradually evolve, spread and accumulate, alongside long-term regional differences in things like the shape of the face and the size of the nose.
A different model, known as the assimilation model, took the new fossil and genetic data on board and gave Africa a key role in the evolution of modern features. However, this model envisaged a much more gradual spread of those features from Africa than did mine. Neanderthals and archaic people like them were assimilated through widespread interbreeding. Thus the evolutionary establishment of modern features was a blending process rather than a rapid replacement.

So who was right? Genetic data continued to accumulate through the 1990s in support of the recent African origin model, both from recent human populations and Neanderthal fossils. Recent massive improvements in recovery and analysis of ancient DNA have produced even more information, some of it very surprising. Fossil fragments from Croatia have yielded up a nearly entire Neanderthal genome, providing rich data that promise insights into their biology – from eye colour and hair type through to skull shape and brain functions.

These latest results have largely confirmed a separation from our lineage about 350,000 years ago. But when the new Neanderthal genome was compared in detail with modern humans from different continents, the results produced an intriguing twist to our evolutionary story: the genomes of people from Europe, China and New Guinea lay slightly closer to the Neanderthal sequence than did those of Africans. Thus if you are European, Asian or New Guinean, you could have 2.5% of Neanderthal DNA in your genetic make-up.
The most likely explanation for this discovery is that the ancestors of today's Europeans, Asians and New Guineans interbred with Neanderthals (or at least with a population that had a component of Neanderthal genes) in North Africa, Arabia or the Middle East, as they exited Africa about 60,000 years ago. That ancient human exodus may have involved only a few thousand people, so it would have taken the absorption of only a few Neanderthals into a group of H. sapiens for the genetic effect – greatly magnified as modern human numbers exploded – to be felt tens of thousands of years later.

The breakthrough in reconstructing a Neanderthal genome has been mirrored across Asia in equally remarkable work on the human group that has become known as the "Denisovans". A fossil finger bone, about 40,000 years old, found in Denisova Cave, Siberia, together with a huge molar tooth, could not be assigned to a particular human species, though it has also had much of its genome reconstructed. This has revealed a previously unrecognised Asian offshoot of the Neanderthal line, but again with a twist. These Denisovans are also related to one group of living humans – the Melanesians of southeast Asia (and probably their Australian neighbours too). These groups also carry about 5% of Denisovan DNA from another interbreeding event that must have happened as their ancestors passed through southern Asia over 40,000 years ago.

So where does this added complexity and evidence of interbreeding with Neanderthals and Denisovans leave my favoured Recent African Origins model? Has it been disproved in favour of the multiregional model, as some have claimed? I don't think so. As we have seen, back in 1970, no scientists held the view that Africa was the evolutionary home of modern humans; the region was considered backward and largely irrelevant, with the pendulum of scientific opinion strongly swinging towards non-African and Neanderthal ancestry models. Twenty years later, the pendulum was starting to move in favour of our African origins, as fossil evidence began to be reinforced by the clear signals of mitochondrial DNA. The pendulum swung even further with growing fossil, archaeological and genetic data in the 1990s.

Now, the advent of huge amounts of DNA data, including the Neanderthal and Denisovan genomes, has halted and even reversed that pendulum swing, away from absolute replacement. Instead we are looking at a mixed replacement-hybridisation or "leaky replacement" model. This dynamism is what makes studying human evolution so fascinating. Science is not about being right or wrong, but about gradually approaching truth about the natural world.

The big picture is that we are still predominantly of recent African origin (more than 90% of our genetic ancestry). But is there a special reason for this observation? Overall, the pre-eminence of Africa in the story of our origins does not involve a special evolutionary pathway but is a question of the continent's consistently large habitable areas which gave greater opportunities for morphological and behavioural variations, and for genetic and behavioural innovations to develop and be conserved. "Modernity" was not a package that had an origin in one African time, place and population, but was a composite whose elements appeared at different times and places, and then gradually coalesced to assume the form we recognise today.

My studies have led me to a greater recognition in recent human evolution of the forces of demography (the need for large populations and social networks to make progress), drift and contingency (chance events), and cultural rather than natural selection than I had considered before. It seems that cultural "progress" was a stop-start affair for much of our evolution, until human groups were large, had long-lived individuals, and wide social networks, all helping to maximise the chances that innovations would survive and accumulate.

Linnaeus said of Homo sapiens "know thyself". Knowing ourselves means a recognition that becoming modern is the path we perceive when looking back on our own evolutionary history. That history seems special to us, of course, because we owe our very existence to it. Those figures of human species (usually males, who become increasingly hairless and light-skinned) marching boldly across the page have illustrated our evolution in many popular articles, but they have wrongly enshrined the view that evolution was simply a progression leading to us, its pinnacle and final achievement.

Nothing could be further from the truth. There were plenty of other paths that could have been taken; many would have led to no humans at all, others to extinction, and yet others to a different version of "modernity". We can inhabit only one version of being human – the only version that survives today – but what is fascinating is that palaeoanthropology shows us those other paths to becoming human, their successes and their eventual demise, whether through failure or just sheer bad luck.

Sometimes the difference between failure and success in evolution is a narrow one. We are certainly on a knife-edge now, as we confront an overpopulated planet and the prospect of global climate change on a scale that humans have never faced before. Let's hope our species is up to the challenge.
Professor Chris Stringer is the research leader in human origins at the Natural History Museum, London

Source The Guardian

Self-assembling Electronic Nano-components

2011-06-21T01:55:00.000-07:00

Magnetic storage media such as hard drives have revolutionized the handling of information: We are used to dealing with huge quantities of magnetically stored data while relying on highly sensitive electronic components. And hope to further increase data capacities through ever smaller components. Together with experts from Grenoble and Strasbourg, researchers of KIT’s Institute of Nanotechnology (INT) have developed a nano-component based on a mechanism observed in nature.

“Self-organization” of nano-devices: Magnetic molecules (green) arrange on a carbon nanotube (black) to build an electronic component.

What if the very tininess of a component prevented one from designing the necessary tools for its manufacture? One possibility could be to “teach” the individual parts to self-assemble into the desired product. For fabrication of an electronic nano-device, a team of INT researchers headed by Mario Ruben adopted a trick from nature: Synthetic adhesives were applied to magnetic molecules in such a way that the latter docked on to the proper positions on a nanotube without any intervention. In nature, green leaves grow through a similar self-organizing process without any impetus from subordinate mechanisms. The adoption of such principles to the manufacture of electronic components is a paradigm shift, a novelty.

The nano-switch was developed by a European team of scientists from Centre National de la Recherche Scientifique (CNRS) in Grenoble, Institut de Physique et Chimie des Matériaux at the University of Strasbourg, and KIT’s INT. It is one of the invention’s particular features that, unlike the conventional electronic components, the new component does not consist of materials such as metals, alloys or oxides but entirely of soft materials such as carbon nanotubes and molecules.

Terbium, the only magnetic metal atom that is used in the device, is embedded in organic material. Terbium reacts highly sensitively to external magnetic fields. Information as to how this atom aligns along such magnetic fields is efficiently passed on to the current flowing through the nanotube. The Grenoble CNRS research group headed by Dr. Wolfgang Wernsdorfer succeeded in electrically reading out the magnetism in the environment of the nano-component. The demonstrated possibility of addressing electrically single magnetic molecules opens a completely new world to spintronics, where memory, logic and possibly quantum logic may be integrated.

The function of the spintronic nano-device is described in the July issue of Nature Materials (DOI number: 10.1038/Nmat3050)for low temperatures of approximately one degree Kelvin, which is -272 degrees Celsius. Efforts are taken by the team of researchers to further increase the component’s working temperature in the near future.

Source KIT

Cocaine addiction linked to brain abnormalities

2011-06-20T21:10:00.000-07:00

Cambridge scientists find differences in key areas of grey matter affecting functions such as memory and attention.

Scans showed cocaine users had enlarged grey matter in areas of the brain associated with processing reward.

Scientists have found "significant abnormalities" in the brains of people addicted to cocaine, which could help explain some of the compulsive behaviour associated with using the drug. It may also hint at why some people are more prone to addiction.

Brain scans revealed that cocaine users had a "dramatic decrease in grey matter" in their frontal lobes, according to researchers, which affected key functions including decision-making, memory and attention, while some of their brain's rewards systems were significantly bigger. Karen Ersche of the Behavioural and Clinical Neuroscience Institute at the University of Cambridge, who led the latest work, found the longer a person had been using cocaine, the poorer their attention was, and the more compulsively they used the drug.
"That is the hallmark of cocaine dependence - namely, that most of them are intelligent people who go to great extents to buy cocaine, to get more cocaine, to put their jobs at risk, their families at risk,They feel like they're driven to use more" said Ersche.

The results were published on Tuesday in the journal Brain. Ersche and her team scanned the brains of 60 people who were dependent on cocaine and compared them to scans of 60 people without any history of drug-taking. "We found significant abnormalities in the brains of the cocaine users," she said.
Specifically, the amount of grey matter in the orbitofrontal cortex was reduced in people with cocaine addiction, an area involved in decision-making and goal-directed behaviour.

Other affected areas included the insula, an area of the brain involved in feedback processing, learning and feelings of cravings. The grey matter in the anterior cingulate, involved in emotional processing and being attentive, was also reduced.
In contrast, a region deep in the brain associated with reward processing, attention and motor movements - the chordate nucleus - was enlarged in subjects who were addicted to the drug. This could explain why those subjects were more prone to addiction but the scientists cannot be sure whether the enlargement is a result of cocaine use.

Laurence John Reed, a clinical senior lecturer in addiction neurobiology at Imperial College London, said the "most impressive" results were the basic comparison of controls and stimulant users, which showed how parts of the brain remodel themselves in response to drugs. "This is a striking and visual example of how addictive stimulant use can result in adaptation of very important brain systems which have a direct correlates with behaviour – specifically inattention, impulsivity and compulsivity – and really does underline why we need a much better neurobiological understanding of the processes involved."

Ersche said that, though she found links between brain structure and cocaine use,her research was not conclusive on which came first. "At the moment, correlation shows me a direct relationship - but I don't know which direction the relationship is. Has this been caused by cocaine, or are people who have this abnormality more vulnerable?"

But the work could be used to help in diagnosis and treatment of addiction.
"We basically show that cocaine is a disorder of the brain, which is a big step," said Ersche. "For a lot of people, it is still a moral issue and willpower has nothing to do with the brain."
Knowing that certain brain areas are abnormal, she said, meant that scientists could try to work out ways of training or medicating the brain to get around the damage.

In a separate study published in the journal Heart, scientists at the Foundation CNR-Tuscan Region in Pisa, Italy, found that heavy cocaine use also causes serious damage to the heart, without any obvious symptoms at the early stages. Scans of the hearts of 25 men with long-term history of cocaine use picked up structural damage in 83% of participants and swelling in the lower left ventricle in around 47%. They also found tissue scarring in 73% of addicts, possibly a result of undetected heart attacks.
Around one in five cocaine addicts suffer from an inflammation of heart muscle, known as myocarditis, and the researchers said that a quarter of non-fatal heart attacks among the under-45s are associated with cocaine.

Source The Guardian

Improving LED lighting

2011-06-20T21:01:00.000-07:00

Researcher from the University of Miami helps create a smaller, flexible LED.

CORAL GABLES, FL (June 20, 2011) — University of Miami professor at the College of Engineering, Jizhou Song, has helped design an light-emitting diode (LED) light that uses an array of LEDs 100 times smaller than conventional LEDs. The new device has flexibility, maintains lower temperature and has an increased life-span over existing LEDs. The findings are published online by the "Proceedings of the National Academy of Sciences."

Incandescent bulbs are not very efficient, most of the power they use is converted into heat and only a small fraction of the power gets converted to light. Since LEDs reduce energy waste and present an alternative to conventional bulbs.
In this study, the scientists focused on improving certain features of LED lights, like size, flexibility and temperature. Song's role in the project was to analyze the thermal management and establish an analytical model that reduces the temperature of the device.

"The new model uses a silicon substrate, novel etching strategies, a unique layout and innovative thermal management method," says Song, co-author of the study. "The combination of these manufacturing techniques allows the new design to be much smaller and keep lower temperatures than current LEDs using the same electrical power."
In the future, the researchers would also like to make the device stretchable, so that it can be used on any surface, such as deformable display monitors and biomedical devices that adapt to the curvilinear surfaces of the human body.

Source EurekaAlert!

NIU scientists discover simple, green and cost-effective way to produce high yields of highly touted graphene

2011-06-20T20:48:00.000-07:00

DeKalb, Ill. — Scientists at Northern Illinois University say they have discovered a simple method for producing high yields of graphene, a highly touted carbon nanostructure that some believe could replace silicon as the technological fabric of the future.

The focus of intense scientific research in recent years, graphene is a two-dimensional material, comprised of a single layer of carbon atoms arranged in a hexagonal lattice. It is the strongest material ever measured and has other remarkable qualities, including high electron mobility, a property that elevates its potential for use in high-speed nano-scale devices of the future.
In a June communication to the Journal of Materials Chemistry, the NIU researchers report on a new method that converts carbon dioxide directly into few-layer graphene (less than 10 atoms in thickness) by burning pure magnesium metal in dry ice.

“It is scientifically proven that burning magnesium metal in carbon dioxide produces carbon, but the formation of this carbon with few-layer graphene as the major product has neither been identified nor proven as such until our current report,” said Narayan Hosmane, a professor of chemistry and biochemistry who leads the NIU research group.
“The synthetic process can be used to potentially produce few-layer graphene in large quantities,” he said. “Up until now, graphene has been synthesized by various methods utilizing hazardous chemicals and tedious techniques. This new method is simple, green and cost-effective.”
Hosmane said his research group initially set out to produce single-wall carbon nanotubes. “Instead, we isolated few-layer graphene,” he said. “It surprised us all.”

“It’s a very simple technique that’s been done by scientists before,” added Amartya Chakrabarti, first author of the communication to the Journal of Materials Chemistry and an NIU post-doctoral research associate in chemistry and biochemistry. “But nobody actually closely examined the structure of the carbon that had been produced.”

Other members of the research group publishing in the Journal of Materials Chemistry include former NIU physics postdoctoral research associate Jun Lu, NIU undergraduate student Jennifer Skrabutenas, NIU Chemistry and Biochemistry Professor Tao Xu, NIU Physics Professor Zhili Xiao and John A. Maguire, a chemistry professor at Southern Methodist University.
The work was supported by grants from the National Science Foundation, Petroleum Research Fund administered by the American Chemical Society, the Department of Energy and Robert A. Welch Foundation.

Source Northern Illinois University

Einstein's and Fourier's ideas as keys to new humanlike computer vision

2011-06-20T19:14:00.000-07:00

WEST LAFAYETTE, Ind. - Two new techniques for computer-vision technology mimic how humans perceive three-dimensional shapes by instantly recognizing objects no matter how they are twisted or bent, an advance that could help machines see more like people.

The techniques, called heat mapping and heat distribution, apply mathematical methods to enable machines to perceive three-dimensional objects, said Karthik Ramani, Purdue University's Donald W. Feddersen Professor of Mechanical Engineering.

This graphic illustrates a new computer-vision technology that builds on the basic physics and mathematical equations related to how heat diffuses over surfaces. The technique mimics how humans perceive three-dimensional shapes by instantly recognizing objects no matter how they are twisted or bent, an advance that could help machines see more like people. Here, a "heat mean signature" of a human hand model is used to perceive the six segments of the overall shape and define the fingertips.

"Humans can easily perceive 3-D shapes, but it's not so easy for a computer," he said. "We can easily separate an object like a hand into its segments - the palm and five fingers - a difficult operation for computers."

Both of the techniques build on the basic physics and mathematical equations related to how heat diffuses over surfaces.

"Albert Einstein made contributions to diffusion, and 18th century physicist Jean Baptiste Joseph Fourier developed Fourier's law, used to derive the heat equation," Ramani said. "We are standing on the shoulders of giants in creating the algorithms for these new approaches using the heat equation."

As heat diffuses over a surface it follows and captures the precise contours of a shape. The system takes advantage of this "intelligence of heat," simulating heat flowing from one point to another and in the process characterizing the shape of an object, he said.

Findings will be detailed in two papers being presented during the IEEE Computer Vision and Pattern Recognition conference on June 21-23 in Colorado Springs. The paper was written by Ramani, Purdue doctoral students Yi Fang and Mengtian Sun, and Minhyong Kim, a professor of pure mathematics at the University College London.

A major limitation of existing methods is that they require "prior information" about a shape in order for it to be analyzed.

Researchers developing a new machine-vision technique tested their method on certain complex shapes, including the human form or a centaur – a mythical half-human, half-horse creature. The heat mapping allows a computer to recognize the objects no matter how the figures are bent or twisted and is able to ignore "noise" introduced by imperfect laser scanning or other erroneous data.

"For example, in order to do segmentation you have to tell the computer ahead of time how many segments the object has," Ramani said. "You have to tell it that you are expecting, say, 10 segments or 12 segments."

The new methods mimic the human ability to properly perceive objects because they don't require a preconceived idea of how many segments exist.

"We are trying to come as close as possible to human segmentation," Ramani said. "A hot area right now is unsupervised machine learning. This means a machine, such as a robot, can perceive and learn without having any previous training. We are able to estimate the segmentation instead of giving a predefined number of segments."

The work is funded partially by the National Science Foundation. A patent on the technology is pending.

The methods have many potential applications, including a 3-D search engine to find mechanical parts such as automotive components in a database; robot vision and navigation; 3-D medical imaging; military drones; multimedia gaming; creating and manipulating animated characters in film production; helping 3-D cameras to understand human gestures for interactive games; contributing to progress of areas in science and engineering related to pattern recognition; machine learning; and computer vision.

The heat-mapping method works by first breaking an object into a mesh of triangles, the simplest shape that can characterize surfaces, and then calculating the flow of heat over the meshed object. The method does not involve actually tracking heat; it simulates the flow of heat using well-established mathematical principles, Ramani said.

Heat mapping allows a computer to recognize an object, such as a hand or a nose, no matter how the fingers are bent or the nose is deformed and is able to ignore "noise" introduced by imperfect laser scanning or other erroneous data.

"No matter how you move the fingers or deform the palm, a person can still see that it's a hand," Ramani said. "But for a computer to say it's still a hand is going to be hard. You need a framework - a consistent, robust algorithm that will work no matter if you perturb the nose and put noise in it or if it's your nose or mine."

The method accurately simulates how heat flows on the object while revealing its structure and distinguishing unique points needed for segmentation by computing the "heat mean signature." Knowing the heat mean signature allows a computer to determine the center of each segment, assign a "weight" to specific segments and then define the overall shape of the object.

"Being able to assign a weight to segments is critical because certain points are more important than others in terms of understanding a shape," Ramani said. "The tip of the nose is more important than other points on the nose, for example, to properly perceive the shape of the nose or face, and the tips of the fingers are more important than many other points for perceiving a hand."

In temperature distribution, heat flow is used to determine a signature, or histogram, of the entire object.

"A histogram is a two-dimensional mapping of a three-dimensional shape," Ramani said. "So, no matter how a dog bends or twists, it gives you the same signature."

The temperature distribution technique also uses a triangle mesh to perceive 3-D shapes. Both techniques, which could be combined in the same system, require modest computer power and recognize shapes quickly, he said.

"It's very efficient and very compact because you're just using a two-dimensional histogram," Ramani said. "Heat propagation in a mesh happens very fast because the mathematics of matrix computations can be done very quickly and well."

The researchers tested their method on certain complex shapes, including hands, the human form or a centaur, a mythical half-human, half-horse creature.

Source Purdue University

Husband's employment status threatens marriage, but wife's does not, study finds

2011-06-20T18:48:00.000-07:00

A new study of employment and divorce suggest that while social pressure discouraging women from working outside the home has weakened, pressure on husbands to be breadwinners largely remains.
The research, led by Liana Sayer of Ohio State University and forthcoming in the American Journal of Sociology, was designed to show how employment status influences both men's and women's decisions to end a marriage.

According to the study, a woman's employment status has no effect on the likelihood that her husband will opt to leave the marriage. An employed woman is more likely to initiate a divorce than a woman who is not employed, but only when she reports being highly unsatisfied with the marriage.
The results for male employment status on the other hand were far more surprising.
For a man, not being employed not only increases the chances that his wife will initiate divorce, but also that he will be the one who opts to leave. Even men who are relatively happy in their marriages are more likely to leave if they are not employed, the research found.
Taken together, the findings suggest an "asymmetric" change in traditional gender roles in marriage, the researchers say.

That men who are not employed, regardless of their marital satisfaction, are more likely to initiate divorce suggests that a marriage in which the man does not work "does not look like what [men] think a marriage is supposed to," the researchers write. In contrast, women's employment alone does not encourage divorce initiated by either party. That implies that a woman's choice to enter the workforce is not a violation of any marriage norms. Rather, being employed merely provides financial security that enables a woman to leave when all else fails.

"These effects probably emanate from the greater change in women's than men's roles," the researchers write. "Women's employment has increased and is accepted, men's nonemployment is unacceptable to many, and there is a cultural ambivalence and lack of institutional support for men taking on 'feminized' roles such as household work and emotional support."
The research used data on over 3,600 couples taken from three waves of the National Survey of Families and Households. Waves were conducted in 1987-88, 1992-94, and 2001-2.

Source American Journal of Sociology via EurekaAlert!

Bitcoin value plummets as main exchange is hacked

2011-06-20T18:33:00.000-07:00

Bitcoin freefall: the market plummets as large amounts of bitcoins are sold off at rock-bottom prices - bigger circles correspond to larger transactions (Image: Mt. Gox)

Following reports of theft last week, the Bitcoin community suffered another major loss of confidence yesterday when its largest exchange, Mt. Gox, was compromised, causing Bitcoin's value to fall from around $17.5 to just a few cents.

Although the online peer-to-peer currency has no central authority, Mt. Gox has become one of the most important Bitcoin players by allowing people to convert bitcoins to US dollars and back. As Mt. Gox's owner Mark Karpeles explains, the site itself was not hacked, but someone gained access to a computer used by one of Mt. Gox's auditors and stole a read-only copy of its database containing details of over 60,000 accounts.

The attacker then attempted to sell coins from one large account, but was prevented from emptying the account by a $1000 per day withdrawal limit. Even so, the sale caused the value of Bitcoin against the dollar to completely collapse.

Karpeles says that no other accounts were compromised and all trades will be rolled back to before the time of the hack, restoring Bitcoin's value to $17.5. Mt. Gox will also require every user to go through an authentication process to verify ownership of their account, since the leaked database contained encrypted user passwords that if cracked could allow access to other accounts.

While these measures should go some way to restoring faith in Mt. Gox and Bitcoin in general, they are a far cry from Bitcoin's promise of complete decentralisation. Some comments on the Mt. Gox forum are protesting the roll back, but it seems that even digital currency enthusiasts want some form of protection when large amounts of money are at stake. The principles behind the currency itself remain sound, but without a secure way to exchange bitcoins for real-life money, many Bitcoin holders will be looking to cash out.

Source New Scientist

Cracking the code of machine translation

2011-06-20T18:22:00.000-07:00

AUTOMATIC translation services seem like magic. Input some foreign text and you instantly get a decent English version in return - unless your text happens to be in Farsi, Pashto or any number of other widely used languages that computers can't currently translate.

What if there's no Rosetta stone?

That's because machine translation techniques rely on analysing the statistical properties of the same text written in two different languages - a Spanish-English dictionary, for example. "You have parallel data for common language pairs like French-English, but for rare or uncommon language pairs it's very difficult to find bilingual sources," explains Sujith Ravi, a computer scientist at the University of Southern California in Marina Del Rey, who is trying a new approach to the problem.

Ravi and his colleague Kevin Knight treat translation as a cryptographic problem, as if the foreign text were simply English written in an advanced cipher. Their software cracks the code by estimating the probability that a foreign word matches an English word based on the number of times it appears in the text - a frequently occurring word is more likely to mean "the" or "a" than "antidisestablishmentarianism".

To ensure the translation makes sense, the pair use another piece of software to evaluate the quality of English that comes out. This in turn tweaks the probabilities used in the translation software. They tested the system on a collection of short phrases such as "last year" and "the fourth quarter", attempting to translate the Spanish equivalents back into English, along with a number of movie subtitles that existed in both languages.

The resulting translations - known, confusingly, as "monolingual" translations - rated highly compared with standard computer translation techniques. But it remains to be seen whether the models can be scaled up from such short phrases to deal with longer, more complex texts.

Chris Callison-Burch of Johns Hopkins University in Baltimore, Maryland, says Ravi and Knight's method is "extremely promising" but adds that it hasn't proved itself yet. His team is also working on translation software that eschews parallel data. Their version crawls online texts and compares disparate texts from different languages - say, a collection of Spanish blog posts and news stories in English. For example, the word "tsunami" spiked in 2004 and 2011 following the Indian Ocean and Japanese events, as did the equivalent word in Spanish, maremoto, suggesting that they mean the same thing.

Ravi and Knight are also exploring how monolingual methods could help us crack long-lost languages or unknown ciphers (see "Machine versus the Zodiac killer"). But what about the ultimate unknown tongue - could their methods translate an alien language? "Totally," says Ravi. "You could also think of deciphering dolphin-speak."

Monolingual translation might also help soldiers or aid workers react quickly in countries with unfamiliar languages; responding to a bombing in Indonesia or an earthquake in Haiti, for instance.

Don't expect a Google Translate upgrade just yet, though. "They're trying to do something very ambitious," says Phil Blunsom, a machine translation researcher at the University of Oxford. "It's not something you're going to see popping up in commercial systems any time soon."

Machine versus the Zodiac killer

Coded messages apparently sent by a San Francisco serial killer in the late 1960s have baffled cryptanalysts ever since, but Ravi and Knight's translation model could help crack the cipher. The Zodiac killer's code replaced letters with strange symbols and sometimes used multiple symbols for the same letter, making it very hard to decipher.
The first three messages were decoded by hand, revealing them to be parts of a single message, but the fourth remains unsolved to this day. Ravi and Knight's model has successfully cracked the first messages - the first time this has been achieved without human intervention - and they now hope to decode the fourth.

Source New Scientist

Loophole found in genetic traffic laws

2011-06-19T23:17:00.000-07:00

Altered molecule causes protein-making machinery to run stop signs.

Biology’s rules may be full of exceptions, but a new discovery has uncovered a violation in a rule so fundamental that geneticists call it the central dogma.
The molecular equivalent of writing one RNA letter in a different font can change the way a cell’s protein-building machinery interprets the genetic code, Yitao Yu and John Karijolich of the University of Rochester in New York report in the June 16 Nature. They found that occasional conversions of a genetic letter found in RNA into a slightly different form can cause a cell’s protein-building machinery to roll right through a stop sign.

That might seem like a run-of-the-mill molecular traffic violation, but it results in an entirely different protein than the one encoded by DNA — a clear violation of the central dogma.
The central dogma holds that DNA is the repository for all genetic instructions in a cell. The tenet declares that those instructions are carefully transcribed into multiple messenger RNA, or mRNA, copies, which are then read in three-letter chunks called codons by cellular machinery called ribosomes. Ribosomes then convert the mRNA instructions into proteins.

Yu and Karijolich studied pseudouridine, a slightly different version of the RNA component uridine. The enzymes that copy DNA to RNA and vice versa can’t tell the difference between the two components, but the subtle chemical tweak — akin to writing a letter in a hard-to-read, byzantine font — gives an entirely different meaning for the ribosome, the researchers suggest.
The result is “groundbreaking,” says Nina Papavasiliou, a molecular biologist at Rockefeller University in New York City. “It says that we don’t fully understand how ribosomes decode RNAs.”
That discovery could also mean that genes contain more information than scientists have realized, Papavasiliou says.

Pseudouridine is already known to be important for the function of many types of RNA in cells. Yu and Karijolich engineered a system to discover whether mRNAs containing the modified letter might also have a slightly different function than those with plain old uridine. The researchers created a flawed copper-detoxifying gene called CUP1 that contained an early signal to stop making protein. The team also created a system that would cause yeast cells to edit the mRNA, replacing the uridine in the stop codon with pseudouridine. If pseudouridine behaved just like uridine, then cells would prematurely halt production of the detoxifying protein and wouldn’t be able to grow in the presence of copper.
Yeast cells that replaced uridine in the stop sign with pseudouridine could grow on copper, the researchers found. Looking more closely, the team found that instead of reading the stop sign as stop, ribosomes interpreted the pseudouridine-containing codon as an instruction to insert the amino acids serine, threonine, phenylalanine or tyrosine into the protein.

That choice of amino acids by the ribosome has biologists reeling, because those aren’t even the amino acids usually chosen when the protein factories do occasionally run stop signs.
“When you know the literature, you would expect other [amino acids],” says Henri Grosjean, a biochemist and geneticist at the University of Paris-South.
Apparently ribosomes haven’t read those papers.

Whether pseudouridine plays a part in changing the genetic code in nature remains to be seen, but researchers are betting that it does. The implications for health and disease could be great, says Juan Alfonzo, a molecular biologist at the Ohio State University. Pseudouridines may be required to make some proteins correctly, but “misplacing a pseudouridine could make things a physiological mess,” he says, causing some proteins to have flaws, even fatal ones.
And Yu and Karijolich’s technique might be used to fix genetic errors, too. Introducing stop sign–busting pseudouridine into an RNA may one day help people with rare genetic diseases in which one of their genes contains an early stop codon, Alfonzo says.

Source Science News

Companies that combine exports, research outperform competitors

2011-06-19T23:07:00.000-07:00

Economists recognize that companies that export are more productive. However, a more complex relationship between exporting and investing in research and development may better explain the high productivity of companies in "economic miracle" countries such as China and Taiwan, according to a team of economists.
"The old story is that there's some type of magic that makes your company more productive if it exports," said Bee-Yan Aw, professor of economics, Penn State. "Actually what we found is that really productive firms tend to export in the first place."

The researchers, who released their findings in the current issue of the American Economic Review, said companies that exported and invested in R&D significantly outperformed other companies significantly in productivity, including companies that just began exporting. They examined data on the relationship between R&D investments, exporting practices and productivity for Taiwanese electronic product manufacturing plants from 2000 to 2004.
A company that both invests in R&D and exports is 123 percent more productive than a plant that does neither, said Mark Roberts, professor of economics, Penn State. A plant that exports, but does not invest in R&D, is only 35 percent more productive. A plant that only invests in R&D has productivity that is twice as high.

According to Aw, manufacturers may be tempted to seize higher productivity gains by investing only in R&D and not in exports, but the costs of implementing new technology and updating equipment could be prohibitive.
"There are often higher costs associated with research and development that may make it impractical for companies to implement," said Aw. "Exporting may actually be a more desirable way to improve productivity initially because it is relatively low cost."
The Penn State researchers, who worked with Daniel Yi Xu, assistant professor of economics, New York University, said companies that export gain a competitive edge by learning more from their customers, which are often larger companies in Western countries.

Because companies that export are more productive, they may have a significant advantage over non-exporting firms that are hoping to sell their goods overseas. Government programs can help ease this transition for non-exporting companies that are looking for customers in foreign markets, according to Aw.
"Governments can set up programs that help non-exporting companies connect with customers in other countries," said Aw. "In fact, that's what a lot of countries are already doing."

Source EurekaAlert!

Geneticists discover technique to tackle mutant DNA

2011-06-19T21:17:00.000-07:00

Scientists at the University of Rochester believe they have found a way to alter the genes that can cause disease.

Scientists have hit on a genetic trick that opens up fresh avenues for the treatment of devastating diseases, such as cystic fibrosis, muscular dystrophy and certain forms of cancer.

The technique corrects glitches in genetic machinery that cause the body to make faulty versions of proteins that can lead to the onset of disease.
Although the work is at an early stage, the strategy represents a radical new approach to tackling mutations that give rise to an estimated one third of all genetic disorders.

"This is a really powerful concept that can be used to try to suppress the tendency of individuals to get certain debilitating, and sometimes fatal genetic diseases," said Robert Bambara at the University of Rochester Medical Centre, who was not involved in the study.
Proteins are the workhorses of the body and carry out all of the functions necessary for life, from metabolising food to building cells and directing immune attacks on unwelcome invaders. Taken together, the cells of the body make around 20,000 different proteins.

The instructions to make human proteins are carried by around 25,000 genes that are found in almost every cell. To make a protein, each "letter" of a gene must be copied into a single strand of genetic material called messenger RNA (mRNA). The cell then takes this mRNA and uses it as a blueprint to build the protein in a process called translation.
But the business of making proteins does not always proceed smoothly. Mutations in genes or mRNA can give rise to faulty proteins that in many cases trigger disease.
John Karijolich and Yi-Tao Yu at the University of Rochester Medical Centre focused on a type of mutation that causes strands of mRNA to contain premature "halt" signs called stop codons. These order cells to stop making proteins before the job is finished. As a result, affected cells churn out short and incomplete proteins.
Writing in the journal, Nature, the scientists describe a series of experiments in which they used short strands of RNA to correct faulty mRNA, by switching unwanted stop signs into "go" signs. To their surprise, treated cells began to produce healthy, full-length proteins again.

"This is a very exciting finding," Yu said. "No one ever imagined that you could alter a stop codon the way we have and allow translation to continue uninterrupted like it was never there in the first place."
"Our work is still really early with regard to clinical application," Yu told the Guardian. "However, we believe it will eventually offer a potential therapeutic option for premature stop codon-caused diseases, such as cystic fibrosis and muscular dystrophy."

Source The Guardian

IPCC asks scientists to assess geo-engineering climate solutions

2011-06-19T21:12:00.000-07:00

Leaked documents ahead of key Lima meeting suggest UN body is looking to slow emissions with technological fixes rather than talks.

Lighter-coloured crops, aerosols in the stratosphere and iron filings in the ocean are among the measures being considered by leading scientists for "geo-engineering" the Earth's climate, leaked documents from the UN climate science body show.

One of the geo-engineering solutions to climate change is to spray seawater droplets into marine clouds to make them reflect more sunlight.

In a move that suggests the UN and rich countries are despairing of reaching agreement by consensus at global climate talks, the US, British and other western scientists will outline a series of ideas to manipulate the world's climate to reduce carbon emissions. But they accept that even though the ideas could theoretically work, they might equally have unintended and even irreversible consequences.

The papers, leaked from inside the Intergovernmental Panel on Climate Change (IPCC), ahead of a geo-engineering expert group meeting in Lima in Peru next week, show that around 60 scientists will propose or try to assess a range of radical measures, including:
• blasting sulphate aerosols into the stratosphere to reflect sunlight into space;
• depositing massive quantities of iron filings into the oceans;
• bio-engineering crops to be a lighter colour to reflect sunlight; and
• suppressing cirrus clouds.

Other proposals likely to be suggested include spraying sea water into clouds to reflect sunlight away from the Earth, burying charcoal, painting streets and roofs white on a vast scale, adding lime to oceans and finding different ways to suck greenhouse gases out of the air and deposit heat deep into oceans.
The meeting is expected to provide governments with a scientific assessment of geo-engineering technologies, but is widely expected to be in favour of more research and possibly large-scale experimentation despite an international moratorium adopted by the UN last year in Japan.

This week, more than 125 environment, development and human rights groups from 40 countries published a letter sent to Rajendra Pachauri, the Nobel prize-winning head of the IPCC, warning that the body had no mandate to consider the legality or political suitability of using geo-engineering.
"Asking a group of geo-engineering scientists if more research should be done is like asking bears if they would like honey," said the letter, signed by groups including Friends of the Earth International, Via Campesina and ETC.

Concern over the IPCC meeting centres on who should decide what kind of geo-engineering takes place, and how it should be regulated and monitored. Some projects might, if they work, unintentionally change weather patterns and possibly affect farming and livelihoods in some of the most vulnerable areas in the world.
"[Geo-engineering] is not a scientific question, it is a political one. International peasant organisations, indigenous peoples and social movements have all expressed outright opposition to such measures as a false solution to the climate crisis," says the letter.

Britain is, along with the US, strongly backing geo-engineering research and has supported scientists with millions of pounds of university research, including a Bristol University plan to develop a "hose" held up by balloons through which sulphates can be sent into the stratosphere. The Royal Society is now trying to develop international guidelines and principles and is holding workshops around the world.
In a letter to the Guardian this week, Georgina Mace, professor of conservation science at Imperial College, London and Catherine Redgwell, professor of international law at UCL, said that investment in geo-engineering research had already begun and, "without international governance structures, schemes could soon be implemented unencumbered by the safeguards needed".

But according to abstracts of the papers, Redgwell will advise the IPCC in Peru next week that no new laws should be adopted. "A multilateral geo-engineering treaty is not likely or desirable. The appetite for climate change law-making is low."
The main principles, she suggests, should be that geo-engineering is a "public good", there should be public participation in schemes and independent assessment of the impacts.

"Geo-engineering is not a public good but could be a giant international scandal with devastating consequences on the poor," said Diana Bronson, researcher with international NGO the ETC Group.
In the papers, many of the scientists accept there are that major uncertainties around the technologies. However, the scientific steering group of the meeting, which will assess the technologies, includes many well-known geo-engineering advocates who have called for public funds to conduct large-scale experiments as well as scientists who have patents on geo-engineering technologies or financial interests in the technologies.
The meeting has been given added weight because last week, Christiana Figueres, head of the UNFCCC, told the Guardian that the world may have to investigate geo-engineering because emissions were continuing to rise.

"We are putting ourselves in a scenario where we will have to develop more powerful technologies to capture emissions out of the atmosphere", she said. "We are getting into very risky territory."

Source The Guardian

Cervical cancer vaccine a success, says Lancet report

2011-06-19T21:03:00.000-07:00

Australian study of injection to protect against HPV virus reveals drop in high-grade abnormalities among under-18s.

Vaccinations against the HPV virus which causes cervical cancer have been a success, according to a new study. Photograph: Voisin/Phanie/Rex Features

The first evidence has emerged that nationwide vaccination programmes for young women against HPV, the virus that triggers cervical cancer, are likely to cut the numbers who get the disease.
A study in Australia, one of the first countries to introduce the vaccination, has shown a drop in high-grade cervical abnormalities – changes to the cells in the neck of the womb that can be the precursor to cancer.
Australia introduced nationwide HPV (human papilloma virus) vaccination for women aged 12 to 26 from 2007.

While it will take many years to find out whether vaccination programmes definitely reduce the numbers of cervical cancers in the population, Australian scientists were able to analyse the results from their screening programme to find out whether there has been any drop in the number of young women with abnormal cell changes that are the precursor of cancer.

Publishing in the Lancet medical journal, they report that the proportion of girls aged 17 and younger with high-grade abnormalities fell by almost half, from 0.80% to 0.42%.
But there was no drop in the numbers of women with cervical abnormalities who were older than 17. This is unsurprising since the vaccine is known to be most effective if given to girls before they become sexually active.
That finding, say the authors, "reinforces the appropriateness of the targeting of prophylactic HPV vaccines to pre-adolescent girls".

The findings were greeted with international interest.
"The not-so-cautious optimist in us wants to hail this early finding as true evidence of vaccine effect," write Dr Mona Saraiya and Dr Susan Hariri of the Centres for Disease Control and Prevention in Atlanta, US, in a linked commentary for the journal.
But they said they wanted to know more about the vaccine status of the individuals (each woman is supposed to have three shots) and wanted more work to establish whether the reductions in potential cancers were really a result of vaccination or some other cause.

Michael Quinn, professor of gynaecology and gynaecologic oncology at the University of Melbourne, said: "The study is the first anywhere in the world to show falling rates of high-grade change in very young women.
"Although this is likely to be due to the effects of the vaccination programme, further analysis of information linking women's smear history to their vaccination history will be needed to prove that the fall is entirely due to vaccination rather than other factors."
Public health experts say that women should not assume they are not vulnerable to the disease after vaccination and should still go for regular screening checks.

The UK introduced its own cervical cancer vaccination programme in September 2008, offering the jab in school to 12- and 13-year-old girls, with catch-up programmes for those up to 18.
The cost was expected to be £100m a year. Of the two available vaccines, the UK decided to buy Cervarix, manufactured by the British company GlaxoSmithKline, even though it does not offer the additional protection against genital warts of the alternative, Gardasil.

In spite of worries that parents would refuse to have their daughters vaccinated against what is essentially a sexually-transmitted virus, the take-up has been good, according to figures from the Department of Health.
In the school year 2009/10, more than three-quarters of 12- to 13-year-olds were given all three doses of the vaccine.
• This article was amended on 17 June 20-11. The original included a reference to a fall of 0.38%. This has been corrected.

Source The Guardian

U.T. Experiment Grapples With Essence of Gravity

2011-06-19T20:56:00.000-07:00

We have all experienced gravity, but even to the brightest minds in science, it remains largely a mystery. Gary J. Hill, an astronomer at the University of Texas at Austin, is trying to change that.

“We don’t know why there’s gravity,” said Mr. Hill, one of the lead astronomers on the Hobby-Eberly Telescope Dark Energy Experiment, or Hetdex, which could turn gravity’s time-honored laws on their head. “We have a pretty good theory of it. It may be that our observations could have a bearing on finally formulating why gravity exists.”

Sky reflects in the primary mirror of the Hobby-Eberly telescope at the McDonald Observatory. The mirror, partly obscured, is made of 91 segments.

Mr. Hill has teamed with Karl Gebhardt, an astronomy professor at U.T., on the $36 million project, which has prevailed despite the threat of natural disasters, potential lack of financing and all the kinks that can throw off a long-term project. The experiment’s goal is to analyze our understanding of how the universe is expanding — with ramifications on gravity, the Big Bang theory and the fate of the universe.

“Not only is the universe expanding, but it’s accelerating,” Mr. Gebhardt said. “And so that’s what we call dark energy — the existence of the acceleration. And that’s the huge thing that no one can explain.”
Granted, in a time of high unemployment, crazy gas prices and water shortages, studying the swelling of the universe might seem out of touch. But when asked about its importance, Steven Weinberg, a Nobel Prize-winning physicist at U.T., said, “Do you really need a sermon on why settling questions about the fundamental laws of nature are worth pursuing?”

For Mr. Hill, 48, and Mr. Gebhardt, 46, even to be in position of rewriting the books is fortunate. The McDonald Observatory — where the dark-energy observations, made with the third-largest telescope in the world, are set to begin next spring after nearly 10 years of development — is about 425 miles west of Austin, in Fort Davis. In April, the Rock House Fire, which started 35 miles south of there, in Marfa, scorched the Davis Mountains surrounding the state-of-the-art observatory, putting it perilously close to going up in flames.
Mother Nature has not been the only threat. Lack of financing for an abstract experiment with little or no immediate pay-off has stymied several similar projects that sprang from the discovery of dark energy in 1998. Now, only a handful of those remain, and none have the proprietary will of Hetdex — a testament to the ego of the state of Texas.

Nearly a third of the money raised for Hetdex, which includes a one-of-its-kind $16 million spectrograph created by Mr. Hill called Virus (Visible Integral-Field Replicable Unit Spectrograph), came from private in-state sources. The largest donor, Harold Simmons, a Dallas investor and U.T. alumnus whom Forbes magazine ranked as the 55th-richest person in the United States, gave two gifts totaling $6.5 million. (Mr. Simmons’s family foundation is a major donor to The Texas Tribune.)
“I could see that figuring out the nature of dark energy would be of historic importance, not just in astronomy but for all science, and for all humankind,” Mr. Simmons said in an e-mail. “As a proud Texan, I wanted a Texas-based, Texas-led project to be first.”

Meanwhile, broader debate has recently emerged over the role of academic research in state universities, with some conservatives calling for a greater emphasis on teaching to improve efficiency. But many in the higher education community have argued that the benefits of research extend beyond universities’ bottom lines.
“This is helping us train the next generation of engineers and leaders in these fields of technology,” Mr. Gebhardt said of Hetdex, which derives about a quarter of its financing from U.T. and a $6 million special biennial line item in the state budget. “And that’s important because we don’t have a lot of that in the country.”
The impact on education goes even deeper, Mr. Hill said, explaining: “Kids, when they’re 5 or 6 or 7, these are the ones who get interested in science through fields like paleontology and astronomy. These are exciting areas.”

Where the education system falls short, Mr. Hill added, “is failing to take that excitement and actually train them so they remain excited through college.”
The McDonald Observatory’s history also provides a valuable lesson in collaboration.
On a recent tour, Thomas Barnes, the observatory’s superintendent, said U.T. did not even have an astronomy department in 1926, when William Johnson McDonald, a banker from Paris, Tex., bequeathed his $1.1 million fortune to start an observatory. U.T. enlisted the University of Chicago to design and build the operation under the direction of Otto Struve, a Russian-born, fourth-generation astronomer who operated the McDonald Observatory for 30 years, ushering it into the U.T.-led era.

“Better a foreigner than a damn Yankee,” one of the U.T. regents at the time said of Mr. Struve’s appointment, according to Mr. Barnes.
And now the U.T. astronomy department has a chance to enhance its history.
“There will only be one time when we figure out what is in the universe, and then it gets placed in the textbooks,” Mr. Gebhardt said. “We are basically living through that time now.”

Source The New York times

Gender-spotting tool could have rumbled fake blogger

2011-06-19T20:39:00.000-07:00

Software that guesses a writer's gender could have prevented the world being duped into believing a blog that opposed the Syrian government and was striking out for gay rights was written by a young lesbian living in the country.

It turned out the author of the blog, "Gay Girl in Damascus", was a man – something the online gender checker would have picked up on. When New Scientist fed the text of the last blog post into the software, it said that the author was 63.2 per cent likely to be male.

Developed by Na Cheng and colleagues at the Stevens Institute of Technology in Hoboken, New Jersey, the ever-improving software could soon be revealing the gender of online writers – whether they are blogging, emailing, writing on Facebook or tweeting. The team say the software could help protect children from grooming by predators who conceal their gender online.

The fake blog highlights the problem of people masking their identity online. The truth about Amina Abdullah only emerged when the blogger disappeared, supposedly snatched by militiamen.

Online contacts realised that none of them had ever met Amina, and it turned out her blog photo had been stolen from a Facebook page. Then a 40-year-old American, Tom MacMaster living in Edinburgh, UK, confessed that he had been writing the blog all along.

Gender analysis

To determine the gender of a writer or blogger, Cheng and her colleagues Rajarathnam Chandramouli and Koduvayur Subbalakshmi wrote software that allows users to either upload a text file or paste in a paragraph of 50 words or more for gender analysis.

After a few moments, the program spits out a gender judgement: male, female or neutral. The neutral option points to how much of the text has been stripped of any indication of gender. This is something particularly prevalent in scientific texts, the researchers say.

To write their program, the team first turned to vast tranches of bylined text from a Reuters news archive and the massive email database of the bankrupt energy firm Enron. They trawled these documents for "psycho-linguistic" factors that had been identified by previous research groups, such as specific words and punctuation styles.

In total they found 545 of these factors, says Chandramouli, which they then honed down to 157 gender-significant ones. These included differences in punctuation style or paragraph lengths between men and women.

Other gender-significant factors included the use of words that indicate the mood or sentiment of the author and the degree to which they use "emotionally intensive adverbs and affective adjectives such as really, charming or lovely" which were used more often by women, says Chandramouli. Men were more likely to use the word "I", for example, whereas women used questions marks more often.

Bayesian algorithms

Finally, the software combined these cues using a Bayesian algorithm, which guesses gender based on the balance of probabilities suggested by the telltale factors. The work will appear in an upcoming edition of the journal Digital Investigation.

It doesn't always work, however. When the software is fed text, its judgement on a male or female writer is only accurate 85 per cent of the time – but that will improve as more people use it. That's because users get the chance to tell the system when it has guessed incorrectly, helping the algorithm learn. The next version will analyse tweets and Facebook updates.

Bernie Hogan, a specialist in social network technology at the Oxford Internet Institute in the UK, thinks there is a useful role for such technology. "Being able to provide some extra cues as to the gender of a writer is a good thing – it can only help."

Even a "neutral" decision might indicate that someone is trying to write in a gender voice that does not come naturally to them, he says. "It could be quite telling."

Testing the gender software

What did the gender identifier make of three well-known authors? We fed it some sample text to find out.
V. S. Naipaul, a winner of the Nobel prize for literature, claims he can tell a woman's writing by reading just two paragraphs of text, and controversially thinks female authors are no match for his writing. The software's verdict on this extract from his book The Enigma of Arrival: 88.4 per cent male.
Mary Evans was a female novelist who famously wrote under the male nom de plume George Eliot. The software has the measure of her, though. Its analysis of the writer's gender from the first paragraphs of Middlemarch: 94.6 per cent female.

More than 14,000 of Sarah Palin's emails were released by the state of Alaska last week after a lengthy campaign by various media organisations to obtain access to them. One email from the archive was put through the system, but the software got it wrong: 70.77 per cent male.

Source New Scientist

50-year search for calcium channel ends

2011-06-19T20:31:00.000-07:00

Cell's power generator depends on long-sought protein.

Boston, MA (June 19, 2011)—Mitochondria, those battery-pack organelles that fuel the energy of almost every living cell, have an insatiable appetite for calcium. Whether in a dish or a living organism, the mitochondria of most organisms eagerly absorb this chemical compound. Because calcium levels link to many essential biological processes—not to mention conditions such as neurological disease and diabetes—scientists have been working for half a century to identify the molecular pathway that enables these processes.

After decades of failed effort that relied on classic biochemistry and membrane protein purification, Vamsi Mootha, HMS associate professor of systems biology, and colleagues have discovered, through a combination of digital database mining and laboratory assays, the linchpin protein that drives mitochondria's calcium machinery.
"This channel has been studied extensively using physiology and biophysics, yet its molecular identity has remained elusive," said Mootha, who also has appointments at Massachusetts General Hospital and at Broad Institute. "But thanks to the Human Genome Project, freely downloadable genomic databases, and a few tricks -- we were able to get to the bottom of it."

These findings will appear online June 19 in Nature.

The results build on work from Vamsi and his group over the past decade. In 2008, he and his team published a near-comprehensive protein inventory, or proteome, of human and mouse mitochondria. This inventory, called MitoCarta, consisted of just over 1,000 proteins, most of which had no known function.
In a September 2010 paper, Mootha's group described using the MitoCarta inventory to identify the first protein specifically required for mitochondrial calcium uptake. Their strategy was simple. They knew that mitochondria from humans and Trypanosomes (a parasitical organism), but not baker's yeast, are capable of absorbing large amounts of calcium. By simply overlapping the mitochondrial protein profiles of these three organisms, the group could spotlight roughly 50 proteins out of the 1,000 that might be involved with calcium channeling. They found that one protein, which they dubbed MICU1, is essential for calcium uptake.

"That was an significant advance for the field," says Mootha. "We showed that MICU1 was required for calcium uptake, but because it did not span the membrane, we doubted it was the central component of the channel. But what it provided us with was live bait to then go and find the bigger fish."
Traditionally, researchers used standard laboratory methods for such a fishing exhibition, such as attaching biochemical hooks to the protein, casting it into the cell's cytoplasm, then reeling it back in the hope that another, related protein will have bitten. But MICU1's function as a regulator of a membrane channel made this technically prohibitive. Instead, graduate student Joshua Baughman and postdoctoral researcher Fabiana Perocchi went fishing in publicly available genomic databases.

With MICU1 as their point of reference, they scoured those databases that measure whole genome RNA and protein expression, as well as an additional database containing genomic information for 500 species, and looked for proteins whose activity profile mirrored MICU1's. A single anonymous protein with no known function stood out. The researchers named it MCU, short for "mitochondrial calcium uniporter."
To confirm that MCU is central to mitochondria's calcium absorption, the team collaborated with Alnylam Pharmaceuticals, a company that leverages a laboratory tool called RNAi in order to selectively knock out genes in both cells and live animals. Using one of the company's platforms, the researchers deactivated MCU in the livers of mice. While the mice displayed no immediate reaction, the mitochondria in their liver tissue lost the capacity to absorb calcium.
This basic science finding may prove relevant in certain human diseases. "We've known for decades now that neurons in the brains of people suffering from neurodegenerative disease are often marked by mitochondrial calcium overload," said Mootha, an expert on rare mitochondrial diseases who sees patients at Massachusetts General Hospital when he's not in the lab.
"We also know that the secretion of many hormones, like insulin, are triggered by calcium spikes in the cell's cytoplasm. By clearing cytosolic calcium, mitochondria can shape these signals. Scientists studying the nexus of energy metabolism and cellular signaling will be particularly interested in MICU1 and MCU. It's still very early, but they could prove to be valuable drug targets for a variety of diseases – ranging from ischemic injury and neurodegeneration to diabetes."

Source EurekaAlert!

New Search Engine Looks for Uplifting News

2011-06-18T18:10:00.000-07:00

Semantic search technology aimed at a positive slant advances with a system that can spot optimism in news articles.

Good news, if you haven't noticed, has always been a rare commodity. We all have our ways of coping, but the media's pessimistic proclivity presented a serious problem for Jurriaan Kamp, editor of the San Francisco-based Ode magazine—a must-read for "intelligent optimists"—who was in dire need of an editorial pick-me-up, last year in particular. His bright idea: an algorithm that can sense the tone of daily news and separate the uplifting stories from the Debbie Downers.

Talk about a ripe moment: A Pew survey last month found the number of Americans hearing "mostly bad" news about the economy and other issues is at its highest since the downturn in 2008. That is unlikely to change anytime soon: global obesity rates are climbing, the Middle East is unstable, and campaign 2012 vitriol is only just beginning to spew in the U.S. The problem is not trivial. A handful of studies, including one published in the Clinical Psychology Review in 2010, have linked positive thinking to better health. Another from the Journal of Economic Psychology the year prior found upbeat people can even make more money.

Kamp, realizing he could be a purveyor of optimism in an untapped market, partnered with Federated Media Publishing, a San Francisco–based company that leads the field in search semantics. The aim was to create an automated system for Ode to sort and aggregate news from the world's 60 largest news sources based on solutions, not problems. The system, released last week in public beta testing online and to be formally introduced in the next few months, runs thousands of directives to find a story's context. "It's kind of like playing 20 questions, building an ontology to find either optimism or pessimism," says Tim Musgrove, the chief scientist who designed the broader system, which has been dubbed a "slant engine". Think of the word "hydrogen" paired with "energy" rather than "bomb."

Web semantics developers in recent years have trained computers to classify news topics based on intuitive keywords and recognizable names. But the slant engine dives deeper into algorithmic programming. It starts by classifying a story's topic as either a world problem (disease and poverty, for example) or a social good (health care and education). Then it looks for revealing phrases. "Efforts against" in a story, referring to a world problem, would signal something good. "Setbacks to" a social good, likely bad. Thousands of questions later every story is eventually assigned a score between 0 and 1—above 0.95 fast-tracks the story to Ode’s Web interface, called OdeWire. Below that, a score higher than 0.6 is reviewed by a human. The system is trained to only collect themes that are "meaningfully optimistic," meaning it throws away flash-in-the-pan stories about things like sports or celebrities.

No computer is perfect, of course, and like IBM's Watson that held its own on Jeopardy! earlier this year, Ode’s slant engine continues to improve with time—and with each mistake. During one test, the slant system that runs Ode labeled a story about the FBI being "asleep at the switch" as positive, perhaps thinking it addressed sleep deprivation. Nor is it ideologically neutral: the U.S. losing ground to China is not such bad news to, well, China.

The goal is not to be naive, either—drowning out the gloom to focus on rainbows and unicorns. "Ignoring reality is not what this is about," Kamp says. "It's looking at the same reality, just looking at a different angle." High unemployment is a problem that seems all bad, he says, but if you approach it from a side door—perhaps profiling people who have founded new business and learned new skills or industries that have benefited from the downturn—it turns into a story that can inspire others, and maybe even lower the jobless rate faster.

Slant identification may have a big future. Researchers say it could eventually specialize Web content for pockets of consumers and make ads more engaging. Its potential to track attitudes in writing could even help address the age-old lament of how liberal or conservative the mainstream media actually is. Gone, too, could be the journalism axiom of "if it bleeds, it leads". If Ode has its way, solution-based news could become the hot new thing for the overwhelmed and dispirited. Imagine a new newsroom mantra: if it succeeds, it leads.

ALMA casts a cold eye on the sky

2011-06-18T17:58:00.000-07:00

One of the grandest ground-based astronomy projects of the coming decade is taking shape in the arid desert of northern Chile. These antennas, each measuring 12 metres across, are part of a much larger array that will eventually be spread a distance of around 16 kilometres.

The Atacama Large Millimeter/submillimeter Array, or ALMA, is being constructed at an altitude of 5000 metres on the Atacama desert's Chajnantor plateau, one of the driest places on the planet. This lack of moisture, combined with the thin atmosphere at high altitude, offers ideal conditions for observing the cosmos at the still mysterious millimetre and submillimetre wavelengths which are emitted by cooler objects.
The first 16 antennas should be in place this month, and scientific observations are scheduled to begin at the end of September. When it is completed in 2013, ALMA will have fifty 12-metre antennas in its main array, plus an additional array of twelve 7-metre and four 12-metre antennas. This will allow it to produce images of extended objects in the night sky such as giant cosmic clouds of gas and dust. All the dishes will work together to observe the sky as one.

"Even using just the first 16 of its 66 antennas, ALMA will already surpass the capabilities of all existing telescopes of its kind, and will provide new insights into star formation as well as the origins of galaxies and planets," says Paola Andreani, manager of the European ALMA Regional Centre at the European Southern Observatory.
ALMA will be used to probe the first stars and galaxies that emerged from the cosmic "dark ages" around 13 billion years ago. The array will also study molecular clouds, the dense regions of gas and dust where stars are born.
The ALMA project is a partnership of Europe, North America and east Asia in cooperation with Chile.
Click here to see a timelapse video of ALMA scanning the night sky.

Source New Scientist

Sync your desktop and phone with a single photo

2011-06-18T17:22:00.000-07:00

I don't know about you, but I am forever pulling up Google Maps on screen, sending them to the printer...and then leaving for an assignment without the printouts. To the rescue comes an MIT artificial intelligence expert and a Google engineer who together developed an app that lets you move onscreen data like maps from your computer screen to a phone - and magically open the mapping program in the exact same state on the mobile device.

To use their forthcoming Deep Shot app, you simply point the phone camera at the PC or Mac screen and click the shutter. "The phone automatically opens up the corresponding application in the corresponding state. The same process can also work in reverse, moving data from the phone to a desktop computer," says MIT.
How? MIT's Tsung-Hsiang Chang and Google's Yang Li have written code that runs on both the computer and the phone. It makes visible onscreen the uniform resource identifier (URI), of which the web link, or uniform resource locator (URL), is a mere subset. Unlike an URL, the URI is the gobbledegook you get when you press the "link" button on a Google Maps or Street View page (hover your cursor over this link and look at the bottom corner of your screen to see it). This describes all the map data on the page and crucially also scales the data for the screen window.

Snap the screen and the URI code is recognised by the phone's app, calling up the mapping app program in the very same running state. It's very cool stuff, although not everyone is so impressed. But best of all, when Google decides to release the app, it'll save me a lot of wasted colour printouts.

High Wired: Does Addictive Internet Use Restructure the Brain?

2011-06-18T17:10:00.000-07:00

Brain scans hint excessive time online is tied to stark physical changes in the brain.

Kids spend an increasing fraction of their formative years online, and it is a habit they dutifully carry into adulthood. Under the right circumstances, however, a love affair with the Internet may spiral out of control and even become an addiction.

Whereas descriptions of online addiction are controversial at best among researchers, a new study cuts through much of the debate and hints that excessive time online can physically rewire a brain.
The work, published June 3 in PLoS ONE, suggests self-assessed Internet addiction, primarily through online multiplayer games, rewires structures deep in the brain. What's more, surface-level brain matter appears to shrink in step with the duration of online addiction.

"I'd be surprised if playing online games for 10 to 12 hours a day didn't change the brain," says neuroscientist Nora Volkow of the National Institute on Drug Abuse, who wasn't involved in the study. "The reason why Internet addiction isn't a widely recognized disorder is a lack of scientific evidence. Studies like this are exactly what is needed to recognize and settle on its diagnostic criteria," she says.

Defining an addiction
Loosely defined, addiction is a disease of the brain that compels someone to obsess over, obtain and abuse something, despite unpleasant health or social effects. And "internet addiction" definitions run the gamut, but most researchers similarly describe it as excessive (even obsessive) Internet use that interferes with the rhythm of daily life.
Yet unlike addictions to substances such as narcotics or nicotine, behavioral addictions to the Internet, food, shopping and even sex are touchy among medical and brain researchers. Only gambling seems destined to make it into the next iteration of the Diagnostic and Statistical Manual of Mental Disorders, or DSM, the internationally recognized bible of things that can go awry with the brain.
Nevertheless, Asian nations are not waiting around for a universal definition of Internet addiction disorder, or IAD.

China is considered by many to be both an epicenter of Internet addiction and a leader in research of the problem. As much as 14 percent of urban youth there—some 24 million kids—fit the bill as Internet addicts, according to the China Youth Internet Association. By comparison, the U.S. may see online addiction rates in urban youth around 5 to 10 percent, say neuroscientists and study co-authors Kai Yuan and Wei Qin of Xidian University in China.
The scope of China's problem may at first seem extraordinary, but not in the context of Chinese culture, says neuroscientist Karen M. von Deneen, also of Xidian University and a study co-author.
Parents and kids face extreme pressure to perform at work and in school, but cheap Internet cafes lurk around the corner on most blocks. Inside, immersive online game realities like World of Warcraft await and allow just about anyone to check out of reality.

"Americans don't have a lot of personal time, but Chinese seem to have even less. They work 12 hours a day, six days a week. They work very, very hard. Sometimes the Internet is their greatest and only escape," according to von Deneen. "In online games you can become a hero, build empires, and submerge yourself in a fantasy. That kind of escapism is what draws young people."
Out of sight of parents, some college kids further cave to online escapism or use gaming to acquire resources in-game and sell them in the real world. In a recent case Chinese prison wardens allegedly forced inmates into the latter practice to convert digital gold into cold-hard cash.

Several studies have linked voluntary and excessive online use to depression, poor school performance, increased irritability and more impulsiveness to go online (confounding addicts' efforts, if they want to at all, to stop pouring excessive time into online games). To study the effects of possible Internet addiction on the brain, researchers began with the Young Diagnostic Questionnaire for Internet addiction.
This self-assessment test, created in 1998 by psychiatrist Kimberly Young of Saint Bonaventure University in New York State, is an unofficial standard among Internet addiction researchers, and it consists of eight yes-or-no questions designed to separate online addicts from those who can manage their Internet use. (Questions range from, "Do you use the Internet as a way of escaping from problems or of relieving an anxious mood?" to "Have you taken the risk of losing a significant relationship, job, educational or career opportunity because of the Internet?".)

The China-based research team picked 18 college-age students who satisfied addict criteria, and these subjects said they spent about 10 hours a day, six days a week playing online games. The researchers also selected 18 healthy controls who spent less than two hours a day online (an unusually low number, says von Deneen). All of the subjects were then plopped into an MRI machine to undergo two types of brain scans.

Brain drain
One set of images focused on gray matter at the brain's wrinkled surface, or cortex, where processing of speech, memory, motor control, emotion, sensory and other information occurs. The research team simplified this data using voxel-based morphometry, or VBM—a technique that breaks the brain into 3-D pixels and permits rigorous statistical comparison of brain tissue density among people.
The researchers discovered several small regions in online addicts' brains shrunk, in some cases as much as a 10 to 20 percent. The affected regions included the dorsolateral prefrontal cortex, rostral anterior cingulate cortex, supplementary motor area and parts of the cerebellum.

What's more, the longer the addiction's duration, the more pronounced the tissue reduction. The study's authors suggest this shrinkage could lead to negative effects, such as reduced inhibition of inappropriate behavior and diminished goal orientation.
But imaging neuroscientist Karl Friston of University College London, who helped pioneer the VBM technique, says gray matter shrinkage is not necessarily a bad thing. "The effect is quite extreme, but it's not surprising when you think of the brain as a muscle," says Friston, who was not involved in the study. "Our brains grow wildly until our early teens, then we start pruning and toning areas to work more efficiently. So these areas may just be relevant to being a good online gamer, and were optimized for that."

(Friston says London taxi drivers provide a telling comparative example of the brain's ability to reshape itself with experience. In the 2006 study, researchers compared taxi drivers' brains with those of bus drivers. The former showed increased gray matter density in their posterior hippocampi—a region linked to maplike spatial navigation and memory. That probably comes as no surprise to London cabbies, who spend years memorizing a labyrinthine system of 25,000 streets, whereas bus drivers have set routes.)
As another crucial part of the new study on Internet addiction, the research team zeroed in on tissue deep in the brain called white matter, which links together its various regions. The scans showed increased white matter density in the right parahippocampal gyrus, a spot also tied to memory formation and retrieval. In another spot called the left posterior limb of the internal capsule, which is linked to cognitive and executive functions, white matter density dropped relative to the rest of the brain.

Disorder under construction
What the changes in both white and gray matter indicate are murky, but the research team has some ideas.
The abnormality in white matter in the right parahippocampal gyrus may make it harder for Internet addicts to temporarily store and retrieve information, if a recent study is correct. Meanwhile, the white matter reduction in the left posterior limb could impair decision-making abilities—including those to trump the desire to stay online and return to the real world. The long-term impacts of these physical brain changes are even less certain. Rebecca Goldin, a mathematician at George Mason University and director of research for STATS, says the recent study is a big improvement over similar work published in 2009. In this older study a different research group found changes in gray matter in brain regions of Internet addicts. According to Goldin, however, the study lacked reliable controls.

The sample sizes of both studies were small—fewer than 20 experimental subjects each. Yet Friston says the techniques used to analyze brain tissue density in the new study are extremely strict. "It goes against intuition, but you don't need a large sample size. That the results show anything significant at all is very telling," Friston notes.
In the end all of the researchers interviewed by Scientific American emphasized significance only goes so far in making a case for IAD as a true disorder with discrete effects on the brain. "It's very important that results are confirmed, rather than simply mining data for whatever can be found," Goldin says.

Source Scientific American

Memory Implant Gives Rats Sharper Recollection

2011-06-18T17:03:00.000-07:00

Scientists have designed a brain implant that restored lost memory function and strengthened recall of new information in laboratory rats — a crucial first step in the development of so-called neuroprosthetic devices to repair deficits from dementia, stroke and other brain injuries in humans.

Though still a long way from being tested in humans, the implant demonstrates for the first time that a cognitive function can be improved with a device that mimics the firing patterns of neurons. In recent years neuroscientists have developed implants that allow paralyzed people to move prosthetic limbs or a computer cursor, using their thoughts to activate the machines. In the new work, being published Friday, researchers at Wake Forest University and the University of Southern California used some of the same techniques to read neural activity. But they translated those signals internally, to improve brain function rather than to activate outside appendages.

“It’s technically very impressive to pull something like this off, given our current level of technology,” said Daryl Kipke, a professor of bioengineering at the University of Michigan who was not involved in the experiment. “We are just scratching the surface when it comes to interacting with the brain, but this experiment shows what’s possible and the great potential of interacting with the brain in this way.”
In a series of experiments, scientists at Wake Forest led by Sam A. Deadwyler trained rats to remember which of two identical levers to press to receive water; the animals first saw one of the two levers appear and then (after being distracted) had to remember to press the other lever to be rewarded. Repeated training on this task teaches rats the general rule, but in each trial the animal has to remember which lever appeared first, to inform the later choice.

The rats were implanted with a tiny array of electrodes, which threaded from the top of the head down into two neighboring pieces of the hippocampus, a structure that is crucial for forming these new memories, in rats as in humans. The two slivers of tissue, called CA1 and CA3, communicate with each other as the brain learns and stores new information. The device transmits these exchanges to a computer.
To test the effect of the implant, the researchers used a drug to shut down the activity of CA1. Without CA1 online, the rats could not remember which lever to push to get water. They remembered the rule — push the opposite lever of the one that first appeared — but not which they had seen first.

The researchers, having recorded the appropriate signal from CA1, simply replayed it, like a melody on a player piano — and the animals remembered. The implant acted as if it were CA1, at least for this one task.
“Turn the switch on, the animal has the memory; turn it off and they don’t: that’s exactly how it worked,” said Theodore W. Berger, a professor of engineering at U.S.C. and the lead author of the study, being published in The Journal of Neural Engineering. His co-authors were Robert E. Hampson and Anushka Goonawardena, along with Dr. Deadwyler, of Wake Forest, and Dong Song and Vasilis Z. Marmarelis of U.S.C.
In rats that did not receive the drug, new memories faded by about 40 percent after a long distraction period. But if the researchers amplified the corresponding CA1 signals using the implant, the memories eroded only about 10 percent in that time.

The authors said that with wireless technology and computer chips, the system could be easily fitted for human use. But there are a number of technical and theoretical obstacles. For one, the implant must first record a memory trace before playing it back or amplifying it; in patients with significant memory problems, those signals may be too weak. In addition, human memory is a rich, diverse neural process that involves many other brain areas, not just CA3 and CA1; implants in this area will be limited.
Still, some restored memories — Where is the bathroom? Where are the pots and pans stored? — could make a big difference in the lives of someone with dementia. “If you’re caring for someone in the house, for example,” Dr. Berger said, “it might be enough to keep the person out of the nursing home.”

Source The New York Times

NASA's James Webb Space Telescope completes first round of cryogenic mirror test

2011-06-18T08:08:00.000-07:00

The first six of 18 segments that will form NASA's James Webb Space Telescope's primary mirror for space observations completed final cryogenic testing this week. The ten week test series included two tests cycles where the mirrors were chilled down to -379 degrees Fahrenheit, then back to ambient temperature to ensure the mirrors respond as expected to the extreme temperatures of space.

(Click on image for higher resolution)

Engineers and technicians guide six James Webb Space Telescope’s mirror segments off the rails after completing final cryogenic testing this week at Marshall.

A second set of six mirror assemblies will arrive at Marshall in late July to begin testing, and the final set of six will arrive in the fall.
The X-ray and Cryogenic Facility at NASA's Marshall Space Flight Center in Huntsville, Ala. provides the space-like environment to help engineers measure how well the telescope will image infrared sources once in orbit.
Each mirror segment measures approximately 4.3 feet (1.3 meters) in diameter to form the 21.3 foot (6.5 meters), hexagonal telescope mirror assembly critical for infrared observations. Each of the 18 hexagonal-shaped mirror assemblies weighs approximately 88 pounds (40 kilograms). The mirrors are made of a light and strong metal called beryllium, and coated with a microscopically thin coat of gold to enabling the mirror to efficiently collect infrared light.

Source EurekaAlert!