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| Sunday, 29 May 2005 |
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| News Business Features Editorial
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Compiled by Vimukthi Fernando How does the brain make its decisions
The discovery promises to enhance understanding of why some brain-damaged people have learning issues, an insight that could eventually lead to the development of more effective treatments for those with brain injury and trauma. "There's a gap between current neurological treatment, which is typically focused on treating symptoms, and neuroscientific research, which is elucidating how the brain works," said Michael Saddoris, a graduate student in the Department of Psychological and Brain Sciences at Johns Hopkins' Krieger School of Arts and Sciences and a co-author of a paper on the topic that appeared in a recent issue of the journal Neuron. "Our work attempts to bridge that gap by providing a mechanism for how the brain operates both under damaged and normal conditions, which could provide a framework for future treatments." The circuit in question is located in a region of the brain called the orbital frontal cortex, (OFC) located right behind the eyes. It encodes the visual and other cues that people and animals use when making decisions about behaviour or during the learning process, said co-author Michela Gallagher, a professor of psychological and brain sciences. "People with lesions in this part of the brain - from strokes or other injury - seem to learn in a normal way, but are then unable to adapt their behaviour when new situations arise, which is perplexing to us," Saddoris said. "Though we still don't know precisely what it is about damage to that area of the brain that causes this, we now know where it is happening, which is an important first step" The researchers used laboratory rats to delve into how the OFC might encode information about decision-making, as well as to examine how the other parts of the brain are affected when the OFC is damaged. Electrodes were planted into the region of the rats' brains that are involved with decision-making and communicate with the OFC. Half the rats' OFC regions were damaged on one side of their brains. The rats - both those with damaged and undamaged OFC regions - then were given a task. They had to learn which odour led to a sugar reward and which led to a bitter and unpleasant outcome: a salty treat. The researchers wanted to observe whether the rats with and without damage to their OFC region were able to track a new outcome - a Pine Sol scent which led to a desired sweet treat, for instance - and whether the neuron firing was similarly affected as it did on previous accounts, signalling its impact on the decision-making process. They found that the neural responses of the OFC-damaged rats remained "locked in;" that is, the damaged rats' brains were unable to adjust to the switch in clues. "It was as if everything was very slowed down for the damaged rats, as if the neural system for their decision-making was moving at a fraction of its normal pace," Saddoris said. "It seems that OFC-lesioned animals are at the mercy of old, irrelevant information with which to make decisions. This is likely the reason people with damage to that area of their brains persist in behaving in certain ways, even when it is obvious that it is not in their best interest to do so." According to Saddoris, these findings demonstrate that the brain is fundamentally altered by damage to the OFC. "It helps explain why people with damage to the OFC behave the way they do," he said. "They have the ability to learn normally about their world, but they have an area of their brains that is sluggish and inflexible in guiding their behaviour, trapping them in a prison of habit, so to speak. These findings give us insight into how the brain is organised." - Newswise ########### Colour coded success Do others see red when an athlete wears a red uniform? Yes, this proves to be true. Researched by Russell A. Hill and Robert A. Barton of the University of Durham, a paper published in the Nature magazine, New USA suggests that athletes wearing red uniforms experience a slight advantage over those decked out in other colours The researchers analysed the outcomes of four sporting events in the 2004 Summer Olympic Games: boxing, taekwondo, Greco-Roman wrestling and freestyle wrestling. All of these competitions involved two-person matches in which the competitors were randomly assigned either red or blue outfits (or body protectors). Their results indicate that the crimson-clad athletes had a small, but statistically significant, advantage and won 60 percent of the time. This effect was seen only in symmetrical contests in which the participants were evenly matched, however, so a new red jersey won't suffice to haul an athlete out of last place. The scientists also investigated the effect of red togs in team sports by analysing results from the Euro 2004 international soccer tournament, in which teams wore different colour uniforms throughout the event depending on their competition. Comparing five teams that had red shirts as one uniform choice, they discovered that the teams performed better-and scored more goals-when playing in red versus white or blue uniforms. Hill and Barton surmise that the benefit of scarlet uniforms is tied to the evolutionary psychology of colour. For a variety of animals, the authors note, red coloration is a sexually selected signal of male quality and the presence and intensity of red colouration correlates to male dominance and testosterone levels. Thus, athletes facing off against opponents sporting red uniforms might subconsciously feel thrown off their game. Hill and Barton conclude that further investigation in the field is warranted and that "the colour of sportswear needs to be taken into account to ensure a level playing field in sport. " - Scientific American ############# The furthest star An international collaboration featuring Ohio State University astronomers has detected a planet in a solar system that, at roughly 15,000 light years from Earth, is one of the most distant ever discovered. In a time when technology is starting to make such finds almost commonplace, this new planet - which is roughly three times the size of Jupiter - is special for several reasons, said Andrew Gould, professor of astronomy at Ohio State. The technique that astronomers used to find the planet worked so well that he thinks it could be used to find much smaller planets, Earth-sized planets, even very distant ones. And because two amateur astronomers in New Zealand helped detect the planet using only their backyard telescopes, the find suggests that anyone can become a planet hunter. Gould and his colleagues have submitted a paper announcing the planet to Astrophysical Journal Letters, and have posted the paper on a publicly available Internet preprint server The team has secured use of NASA's Hubble Space Telescope in late May to examine the star that the planet is orbiting. The astronomers used a technique called gravitational microlensing, which occurs when a massive object in space, like a star or even a black hole, crosses in front of a star shining in the background. The object's strong gravitational pull bends the light rays from the more distant star and magnifies them like a lens. Here on Earth, we see the star get brighter as the lens crosses in front of it, and then fade as the lens gets farther away. On March 17, 2005, Andrzej Udalski, professor of astronomy at Warsaw University and leader of the Optical Gravitational Lensing Experiment, or OGLE, noticed that a star located thousands of light years from Earth was starting to move in front of another star that was even farther away, near the centre of our galaxy. A month later, when the more distant star had brightened a hundred-fold, astronomers from OGLE and from Gould's collaboration (the Microlensing Follow Up Network, or MicroFUN) detected a new pattern in the signal - a rapid distortion of the brightening - that could only mean one thing. "There's absolutely no doubt that the star in front has a planet, which caused the deviation we saw," Gould said. Because the scientists were able to monitor the light signal with near-perfect precision, Gould thinks the technique could easily have revealed an even smaller planet. - Newswise ############# Astral anomaly Astronomers have spent five weeks studying a very strange star - one that is 10 times as massive as our sun and spews 100 trillion tons of gas into space each second - and have found a method to its mad behaviour. Presenting their results last week at a meeting of the Canadian Astronomical Society in Montreal, the researchers report that the object, WR123, undergoes a stable variation that repeats every 10 hours. Located about 19,000 light-years from Earth, WR123 belongs to a class of stars known as Wolf-Rayet stars, which are known for complex, irregular patterns in their brightness. An international team used the Microvariability & Oscillations of Stars (MOST) space telescope to observe the star continuously for five weeks. Instead of chaotic behaviour, the scientists uncovered a pattern within the data. "Finding a clock in a star like WR123 is like finding the Rosetta stone for astronomers studying massive stars," says team member Laure Lefevre of the University of Montreal "However, although WR123 may vary like clockwork, it must be a very strange mechanism indeed. According to the researchers, there are three possible causes of WR123's habitual behaviour: The star's own rotation could be to blame, although the speeds required would have the surface of WR123 moving at nearly 2,000 kilometres a second. The gravity from a closely orbiting star might cause regular fluctuations, but the object would have to be so close to WR123 that it would reside in the latter's own gas envelope. Finally, vibrations within the star's interior structure could be responsible for the variations in brightness, but if that's the case, many other theories about Wolf-Rayet stars would have to be reconsidered. - Scientific American ########## Glowing strong - glowing long Researchers in the laboratory of Boston College Chemistry Professor John T. Fourkas have demonstrated that gold particles comparable in size to a molecule can be induced to emit light so strongly that it is readily possible to observe a single nanoparticle. Fourkas, in collaboration with postdoctoral researcher Richard Farrer and BC undergraduates Francis Butterfield and Vincent Chen, coaxed the particles into a strong emission of visible light using a technique called multiphoton absorption induced luminescence (MAIL). The most efficient gold nanoparticles could be observed at laser intensities lower than those commonly used for multiphoton imaging, in which specific tissues or cells - cancer cells, for example - are fluorescently-labelled using special stains that enable them to be studied. "One of the most exciting aspects of this technique is that it paves the way for being able to observe behaviour in living tissues at the single molecule level," said Fourkas. "The fluorescent molecules commonly used in multiphoton imaging give out only a limited amount of light, 'burn out' quickly under continuous observation, and are prone to blinking on and off. "The gold particles, however, do not blink or burn out, even after hours of observation, and the brightest ones emit much more light than do molecules," he said. "We now have the ability to see single nanoparticles under conditions where people usually look at thousands or millions of stain molecules. This could allow us, for instance, to track a single molecule of a drug in a cell or other biological sample." Other advantages of the technique are that the gold particles can be prepared easily, have very low toxicity, and can readily be attached to molecules of biological interest, said Fourkas. In addition, the laser light used to visualize the particles is at a wavelength range that causes only minimal damage to most biological tissue. - Newswise ############# Fading beauty
As scientific research paves new avenues, will the hardest, most difficult to find and most valuable mineral on earth - the 'Diamond' go out of fashion? It seems that the day will dawn, soon when every woman will be able to wear a diamond - artificially manufactured but sometimes with qualities that may surpass the natural diamonds, the National Science Foundation of USA reports. Researchers at the Carnegie Institution of Washington, D.C., USA have produced 10-carat, half-inch thick single-crystal diamonds at rapid growth rates (100 micrometers per hour) using a chemical vapour deposition (CVD) process. The size is approximately five times that of commercially available diamonds produced by the standard high-pressure/high-temperature (HPHT) method and other CVD techniques. In addition, the team has made colourless single-crystal diamonds, transparent from the ultraviolet to infrared wavelengths with their CVD process. Most HPHT synthetic diamond is yellow and most CVD diamond is brown, limiting their optical applications. Colourless diamonds are costly to produce and so far those reported are small. This limits general applications of these diamonds as gems, in optics, and in scientific research. Last year, the Carnegie researchers found that HPHT annealing enhances not only the optical properties of some CVD diamond, but also the hardness. Using new techniques, the Carnegie scientists have now produced transparent diamond using a CVD method without HPHT annealing. "High-quality crystals more than three carats are very difficult to produce using the conventional approach," said scientist Russell Hemley, who leads the diamond effort at Carnegie. "Several groups have begun to grow diamond single crystals by CVD, but large, colourless, and flawless ones remain a challenge. Our fabrication of 10-carat, half-inch, CVD diamonds is a major breakthrough." The results were reported at the 10th International Conference on New Diamond Science and Technology, Tsukuba, Japan, early this month. "The rapid synthesis of large, single-crystal diamond is a remarkable scientific achievement, and has implications for a wide range of scientific and commercial applications," said David Lambert, program director in the National Science Foundation (NSF)'s earth sciences division, which funded the research. To further increase the size of the crystals, the Carnegie researchers grew gem-quality diamonds sequentially on the six faces of a substrate diamond plate with the CVD process. By this method, three-dimensional growth of colourless single-crystal diamond in the inch-range is achievable. Finally, new shapes have been fabricated with the blocks of the CVD single crystals. The standard growth rate is 100 micrometres per hour for the Carnegie process, but growth rates in excess of 300 micrometres per hour have been reached, and 1 millimetre per hour may be possible. With the colourless diamond produced at a higher growth rate and low cost, large blocks of diamond should be available for a variety of applications. "The diamond age is upon us," said Hemley. - NSF |
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| Produced by Lake House |
Researchers at The Johns Hopkins University have pinpointed a circuit in
the brain responsible for encoding decision-making behaviour, a circuit that
- if damaged - appears to prevent a person from altering that behaviour when
circumstances change. 
