FERMI Detects Gamma-Rays

Astronomers using NASA's Fermi Gamma-ray Space Telescope have detected gamma-rays from a nova for the first time, a finding that stunned observers and theorists alike. The discovery overturns the notion that novae explosions lack the power to emit such high-energy radiation. A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear explosion. This eruption is equivalent to about 1,000 times the energy emitted by the sun every year!
Gamma rays are the most energetic form of light, and Fermi's Large Area Telescope (LAT) detected the nova for 15 days. Scientists believe the emission arose as a million-mile-per-hour shock wave raced from the site of the explosion. A paper detailing the discovery will appear in the Aug. 13 edition of the journal Science. The story opened in Japan during the predawn hours of March 11, when amateur astronomers Koichi Nishiyama and Fujio Kabashima in Miyaki-cho, Saga Prefecture, imaged a dramatic change in the brightness of a star in the constellation Cygnus. They realized that the star, known as V407 Cyg, was 10 times brighter than in an image they had taken three days earlier. The team relayed the nova discovery to Hiroyuki Maehara at Kyoto University, who notified astronomers around the world for follow-up observations.

On March 13, Goddard's Davide Donato was on-duty as the LAT "flare advocate," a scientist who monitors the daily data downloads for sources of potential interest, when he noticed a significant detection in Cygnus. But linking this source to the nova would take several days, in part because key members of the Fermi team were in Paris for a meeting of the LAT scientific collaboration.

"This region is close to the galactic plane, which packs together many types of gamma-ray sources -- pulsars, supernova remnants, and others in our own galaxy, plus active galaxies beyond them," Donato said. "If the nova had occurred elsewhere in the sky, figuring out the connection would have been easier." The LAT team began a concerted effort to identify the mystery source over the following days. On March 17, the researchers decided to obtain a "target-of-opportunity" observation using NASA's Swift satellite -- only to find that Swift was already observing the same spot. Examining the Swift data, Cheung saw no additional X-ray sources that could account for what Fermi's LAT was seeing. V407 Cyg had to be it.

Half an hour later, Cheung learned from other members of the LAT team that the system had undergone a nova outburst, which was the reason the Swift observations had been triggered. "When we looked closer, we found that the LAT had detected the first gamma rays at about the same time as the nova's discovery," he said. V407 Cyg lies 9,000 light-years away(distance of light travelling for 9000 years). The system is a so-called symbiotic binary containing a compact white dwarf and a red giant star about 500 times the size of the sun. Each decade, the red giant sheds enough hydrogen gas to equal the mass of Earth.
The white dwarf intercepts and captures some of this gas, which accumulates on its surface. As the gas piles on for decades to centuries, it eventually becomes hot and dense enough to fuse into helium. This energy-producing process triggers a runaway reaction that explodes the accumulated gas. The white dwarf itself, however, remains intact.
The blast created a hot, dense expanding shell called a shock front, composed of high-speed particles, ionized gas and magnetic fields. According to an early spectrum obtained by Christian Buil at Castanet Tolosan Observatory, France, the nova's shock wave expanded at 7 million miles per hour -- or nearly 1 percent the speed of light.
The magnetic fields trapped particles within the shell and whipped them up to tremendous energies. Before they could escape, the particles had reached velocities near the speed of light. Scientists say that the gamma rays likely resulted when these accelerated particles smashed into the red giant's wind.
Supernovae remnants endure for 100,000 years and affect regions of space thousands of light-years across.
Kent Wood at NRL compares astronomical studies of supernova remnants to looking at static images in a photo album. "It takes thousands of years for supernova remnants to evolve, but with this nova we've watched the same kinds of changes over just a few days," he said. "We've gone from a photo album to a time-lapse movie."
Sources:
http://www.sciencedaily.com/releases/2010/08/100812172054.htm
http://www.sciencedaily.com/images/2010/08/100812172054-large.jpg

Math Theory calculates Football Odds

A sophisticated new analysis of team tactics predicts a Spanish win in Sunday's FIFA World Cup final and also shows why England were beaten by Germany. Mathematicians and football supporters Dr Javier López Peña and Dr Hugo Touchette from Queen Mary, University of London have collected ball passing data from all of the FIFA World Cup games and analysed it to reveal the nations' different styles of play. Using the mathematical technique called Graph Theory, they have revealed the gaping holes in England's tactics against Germany game and made predictions about the Netherlands-Spain final that could rival the psychic octopus. For each national side, Drs López Peña and Touchette have drawn up a 'network' of passes between players throughout the tournament and analysed how these networks compare between teams. Dr Touchette explains: "Each player in the network is given a score called centrality which measures how vital they are to the network. The higher the centrality score, the bigger the impact if that player wasn't there. This method is most commonly used to make computer networks more robust, but it can also be used to plan football strategy." The Netherlands-Spain prediction The networks reveal Spanish players have made a strikingly high number of passes this tournament, almost 40 per cent more than Germany and twice as many as the Dutch. "The team relies on swift passes that are well distributed among all players, especially between those playing mid-field," said Dr López Peña. David Villa, the tournament's highest goal scorer, has received an average of 37 passes per game, more than any other forward from all the teams. Dr López Peña said: "Villa's performance has been impressive compared with Fernando Torres, who has not scored any goals this tournament. This was reflected in the successful Spanish tactics, with Torres only receiving an average of 13 passes per match, and 37 to Villa." C onversely, the Dutch gameplay is clearly offensive, involving a very low number of passes between players, most of which are aimed at the strikers. Dr López Peña said: "The low number of passes shows the Dutch prefer quick attacks and counterstrikes rather than intricate playing. Their goals are often scored from set pieces such as free kicks and they use their physical presence to beat their opponents." The England-Germany match The analysis shows the English squad to have a balanced line-up with no single player more important than the team as a whole. Dr López Peña said: "The good midfield work of Frank Lampard, Steven Gerrard and Gareth Barry doesn't appear to transfer very well to the forwards, with Wayne Rooney receiving on average three times more passes than Jermain Defoe. This makes the English attack very predictable and easily stoppable by blocking Rooney, who is usually forced to give the ball back to Gerrard." The German network appears even more balanced than the English one, with a higher number of passes, suggesting more circulation of the ball. "Particularly relevant are the passes between Philipp Lahm and Bastian Schweinsteiger and most of the German attacks are built up from the defenders. Mesut Oezil makes good work connecting both sides of the field on the attack, making the German offensive game very effective and hard to defend against. The key player in the German strategy remains Schweinsteiger, who was effectively blocked by the Spanish midfielders' characteristic fast circulation in their semi-final defeat," said Dr López Peña. I find this article very interesting as it has proven that mathematics can indeed calculate, to a great accuracy, the chances of a team winning a match, or even a championship. Hmmm.... I wonder if soccer bets would now be placed with reference to the Graphy Theory. Hopefully, by then, soccer teams would have improved their 'playing network'.


Sources:
http://www.sciencedaily.com/images/2010/07/100709102721-large.jpg
http://www.sciencedaily.com/releases/2010/07/100709102721.htm

Secret to Swatting Flies

Has this question ever occured to you? It sure has to me! Lets hear more about it from the professionals. Using high-resolution, high-speed digital imaging of fruit flies (Drosophila melanogaster) faced with a looming swatter, Michael Dickinson and graduate student Gwyneth Card have determined the secret to a fly's evasive maneuvering. Long before the fly leaps, its tiny brain calculates the location of the impending threat, comes up with an escape plan, and places its legs in an optimal position to hop out of the way in the opposite direction. All of this action takes place within about 100 milliseconds after the fly first spots the swatter. "This illustrates how rapidly the fly's brain can process sensory information into an appropriate motor response," Dickinson says. For example, the videos showed that if the descending swatter--actually, a 14-centimeter-diameter black disk, dropping at a 50-degree angle toward a fly standing at the center of a small platform--comes from in front of the fly, the fly moves its middle legs forward and leans back, then raises and extends its legs to push off backward. When the threat comes from the back, however, the fly (which has a nearly 360-degree field of view and can see behind itself) moves its middle legs a tiny bit backwards. With a threat from the side, the fly keeps its middle legs stationary, but leans its whole body in the opposite direction before it jumps. "We also found that when the fly makes planning movements prior to take-off, it takes into account its body position at the time it first sees the threat," Dickinson says. "When it first notices an approaching threat, a fly's body might be in any sort of posture depending on what it was doing at the time, like grooming, feeding, walking, or courting. Our experiments showed that the fly somehow 'knows' whether it needs to make large or small postural changes to reach the correct preflight posture. This means that the fly must integrate visual information from its eyes, which tell it where the threat is approaching from, with mechanosensory information from its legs, which tells it how to move to reach the proper preflight pose." The results offer new insight into the fly nervous system, and suggest that within the fly brain there is a map in which the position of the looming threat "is transformed into an appropriate pattern of leg and body motion prior to take off," Dickinson says. "This is a rather sophisticated sensory-to-motor transformation and the search is on to find the place in the brain where this happens," he says. Dickinson's research also suggests an optimal method for actually swatting a fly. "It is best not to swat at the fly's starting position, but rather to aim a bit forward of that to anticipate where the fly is going to jump when it first sees your swatter," he says. So next time you see a fly, you know what to do!

Sources:
http://www.sciencedaily.com/releases/2008/08/080828135901.htm
http://www.sciencedaily.com/images/2010/07/100712102812-large.jpg

Grow Taller! Its for your Health!

Short people have a higher risk of heart disease?

Is this true? Well, according to an article "shortness heightens heart risk" in Reader's Digest, women under 153cm and men under 165cm are 1.5 more times likely to develop and die from heart disease. Studies have shown a relationship between stature and heart disease, although for no apparent reason that has been proved. One explanation is that shorter people have generally shorter arteries, which makes them easier to be clogged up.

However, these people should not worry too much as other factors including weight, lifestyle habits such as drinking and exercise also contribute to the possibility of having heart disease. Take note, tall people! Do not think that you will not possibly have heart disease, as you still have a small chance of getting it, albeit lesser than shorter people.

I suggest everyone to lead a healthy lifestyle and live happily(as explained in an earlier post, happy living equals to healthy living), as this is possibly one of the best preventions of heart problems. Take care!

l.auteur

Links:
http://eurheartj.oxfordjournals.org/content/early/2010/06/04/eurheartj.ehq155.full
http://www.express.co.uk/posts/view/179892/Shortness-heightens-heart-riskShortness-heightens-heart-riskShortness-heightens-heart-riskShortness-heightens-heart-riskShortness-heightens-heart-riskShortness-heightens-heart-riskShortness-heightens-heart-risk

Neanderthal Make-up, Care for a sample?

Hi,

Read this article in Reader's Digest and just thought of sharing this piece of weird news with you.

A team of British scientists have discovered painted marine shells used as decorative pendants, together with mineral pigments and shells containing residues of brightlly coloured paints, which collectively suggest that they wore body paint ad were even capable of symbolic thinking. Says lead researcher Professor Joan Zilhao, "The practice of body ornamentation proves that the Neanderthals were as intelligent as their African comtemporaries", "It shows they attained identical levels of cognitive, behavioural and cultural development."

I know that the image of cavemen putting on make-up sounds as absurd to you as it is to me. But remember, they were our ancestors, and they had to be smarter than what we pictures them to be right?

Cheers,
l'auteur

Links for your convenience:
http://www.dailymail.co.uk/news/article-1242118/Neanderthal-make-discovered-Proof-human-subspecies-half-wits.html
http://www.smithsonianmag.com/science-nature/neanderthal.html
http://newslite.tv/2010/01/12/neanderthal-man-wore-makeup-an.html