The Iranian team to the 10th International Astronomy Olympiad in China left here for Tehran after gaining six medals. According to IRNA, the Iranian team won one gold, two silver and three bronze medals and received a diploma of honor.
The team will return to Tehran after a day-long stopover in Moscow.
Teams from sixteen countries including Iran, China, Russia, India, Brazil, Italy, Sweden, Estonia and Lithuania participated in the competitions which were held on October 25-November 2.
An official with the Iranian team, Shahin Jaafarzadeh, said that the Olympiad is aimed at developing and promoting astronomy and expand international contacts among students in the field of astronomy training and brushing up astrological and scientific knowledge.
India with five gold medals proved to be the best participating team in the olympiad, he said.
The 11th International Olympiad is scheduled to be held in India.

A new pathway for treating multiple sclerosis may have been found, if “exciting“ results in mice can be replicated in humans.
MS is an incurable degenerative disease caused by the body’s immune system attacking the protective myelin sheath encasing the nerves that make up the central nervous system. The nerve fibers become increasingly damaged by scar tissue known as sclerosis, which leads to paralysis and loss of speech and vision.
But researchers trying a novel therapy on a mouse version of MS report that the mice showed “almost no inflammation of the myelin sheath and no nerve damage“. Furthermore, MS is characterized by periods of remission and relapse, but the mice recovered with fewer and far less severe relapses.
The therapy targets immune system cells called T-cells. These malfunction in MS patients, producing inflammatory molecules that destroy the myelin sheath. The new treatment, which uses a class of molecules called kynurenines, works by inhibiting the T-cells’ production of inflammatory molecules and prompting them to produce agents that “mop up“ the molecules.
The work began with Larry Steinman at Stanford School of Medicine in California, US, and Michael Platten at the University of Tubingen in Germany, and colleagues, selecting a break-down product--a kynurenine--of a naturally occurring amino acid called tryptophan. Tryptophan is a constituent of most proteins and is known to play an important role in immunity.
The group then induced an MS-type illness called experimental autoimmune encephalomyelitis in 24 mice. On the occasion of their first relapse half were given a daily dose of a synthetic version of the kynurenine for 49 days.
The mice on the tablets also had “re-programmed“ T-cell function, he adds: “Instead of being pro-inflammatory, the T-cells became anti-inflammatory, helping to heal the myelin sheath and suppressing paralysis.“
Examination of the mice at the end of the experiment showed that the treated mice had undamaged nerve cells and no spread of the condition to the brain, whereas this had occurred in the untreated control group. There were no apparent any side effects from the treatment.
Peter Brophy, an MS expert at the University of Edinburgh in the UK, says the research is very exciting, providing an “interesting new pathway after a dearth of new ideas for MS treatments“.
But Brophy cautions that the mouse model of MS, while the best animal model available, does show differences to the human disease and drugs that have worked on mice in the past, have not had the same success in humans.
Another advantage kynurenine has over other candidate treatments is that it is has already proved its safety. Not only is it a derivative of an amino acid that occurs naturally in the body, but it has passed phase I clinical trials in Japan as a potential treatment for allergy sufferers.

The accumulation of fat in the liver, or “fatty liver,“ resulting from accumulation of central body fat, and perhaps not alcohol consumption, may represent an important underlying mechanism for the association between liver enzymes and hypertension, according to Brightsurf.
The study, conducted by researchers at the University at Buffalo, appears in the current issue (November 2005) of the journal Hypertension.
“Our findings extend previous work, and indicate that the association of the liver enzyme GGT with hypertension risk is strongly affected by variation in weight and, above all, body fat distribution,“ said lead author Saverio Stranges, Ph.D., assistant professor of social and preventive medicine in the UB School of Public Health and Health Professions.
“Specifically, we found that GGT was a significant predictor of hypertension only among overweight participants with increased central body fat.
“If we consider that fatty liver is the most common cause of liver injury in the United States, these findings may have both important clinical and public health implications,“ said Stranges.
Alcohol consumption initially was thought to be the link between liver enzymes and high blood pressure for several reasons: Alcoholism is a known risk factor for hypertension; the liver enzyme GGT is a marker for alcohol consumption, and GGT also has been associated with hypertension.
In addition, chronic liver disease, in which GGT levels can be increased, often is associated with heavy alcohol consumption or actual alcoholism.

An ultrasonic pulse is transmitted into the suspension and the signal is captured by a receiver.

Can sound waves travel faster than the speed of light? Yes, says Joel Mobley, a physicist at the University of Mississippi in the US. In simulations Mobley has shown that ultrasound pulses could move at “superluminal“ speeds when they enter water that contains thousands of tiny plastic beads.
Waves moving in a dispersive medium are described by a phase velocity and a group velocity. The phase velocity is the speed at which a wave of a single wavelength moves, and is typically about 1.5 kilometres per second for sound waves in water. However, pulses of light or sound actually contain a range of wavelengths that all move at different speeds: the group velocity is the speed at which the pulse itself moves.
In recent years, it has been shown experimentally that the group velocity of a laser pulse can exceed the speed of light in vacuum--300,000,000 meters per second--in certain situations. However, special relativity is not violated in these experiments because they do not involve the transfer of information, matter or energy.
Mobley has now calculated that the group velocity of a pulse of high-frequency sound waves could be increased by five orders of magnitude by sending it through a small chamber that contains about 8 millilitres of water and some 400,000 tiny plastic spheres. This means that the group velocity would exceed the speed of light in vacuum. The spheres have diameters of about 0.1 mm and account for about 5% of the volume of the water-bead mixture.
The increase in speed is caused by dispersion -- the phenomenon that causes different wavelengths to move at different phase velocities. When the pulse enters the mixture it experiences severe dispersion, which causes the different wavelengths that make up the pulse to travel at very different speeds. This changes the shape of the pulse and can result in the pulse itself moving faster than the speed of light. However, the dispersion also significantly reduces the intensity of the pulses.
“It has long been recognised that such velocities should be possible with acoustic waves,“ Mobley told PhysicsWeb. “My work shows that it can be done in a specific and very simple system and that extreme conditions are not necessary.“
Mobley is now planning experiments to observe the superluminal velocities at the National Center for Physical Acoustics at Mississippi. The main challenge will be to increase the signal-to-noise ratio so that it is possible to detect the pulses, which will have been greatly reduced in intensity by the dispersion.

There is no scientific proof exposure to electrical equipment causes ill health, say scientists.
According to BBC News website, researchers from the Health Protection Agency (HPA) looked at research into electrical sensitivity and reports from patients.
The HPA said people could have real and unpleasant symptoms.
But they said there was insufficient evidence of a direct link between electrical exposure and these symptoms, which can often be disabling.
Electrical sensitivity is a condition which some people attribute to exposure to electromagnetic fields associated with the electricity supply.
It is unclear how many people suffer from the condition, with estimates ranging from a few per thousand people to a few per million.
For the review, experts from the HPA’s Radiation Protection Division looked at scientific studies into electrical sensitivity, as well as other sources of information, such as internet websites maintained by sufferers and self-help groups.
But the researchers did not look at the effects of radiowaves from mobile phones, as most of the studies which look at electrical sensitivity were carried out before they were widely introduced.
From the research they evaluated, the HPA found there were two main groups of symptoms attributed to electrical sensitivity, or electrical hypersensitivity.
People can experience skin symptoms, such as face tingling or redness, often associated with using older types of visual display unit.
Others can experience a broader range of symptoms, such as fatigue and headaches, which vary from person to person.
Most people are only mildly affected, but in around 10%, they are severe enough to be disabling and hinder normal life.
The symptoms reported were similar to those found that people who attribute illness to chemical and other environmental exposures.
However, scientific studies have not found a proven link between exposure to electrical appliances, or power supplies, and symptoms.
In addition, no diagnostic marker - which would identify electrical sensitivity as a defined condition - has been found.

Scientists at IBM have built a silicon chip that uses the combination of built-in miniature heaters and photonic crystal technology to control the speed of light pulses, PhysicsWeb reported.
The silicon waveguide circuit operates at a wavelength of 1.5 microns, which is widely used for telecommunications, and can reduce the “group velocity“ of light by a factor of up to 300.
Over the past decade, physicists have used exotic media such as ultracold atomic gases and various crystals to make “slow“ or “fast“ light. Some groups have managed to stop and store light, while others have demonstrated group velocities greater than the speed of light in vacuum. However, if the speed of light could be controlled with a silicon chip, it might be possible to include such devices in conventional microelectronic circuits.
Yurii Vlasov and colleagues at the IBM T J Watson Research Center in New York have now taken a step in this direction by using a photonic crystal waveguide made of silicon to produce slow light. The waveguide, which is 250 microns long, is etched with a pattern of tiny holes, each 109 nanometres wide, that give the silicon a very high refractive index. An electrical contact acts as a miniature heater.
When a current flows through the heater, it heats up the waveguide, which changes the refractive index and therefore the speed of light in the structure. Applying just 2 milliwatts of electrical power can change the group velocity by a factor of three within 100 nanoseconds.
The IBM work follows a spate of recent work on manipulating the speed of light with optical fibres and various semiconductor structures.

Scientists in Shanghai say they believe they have found a gigantic black hole in the center of our galaxy.
According to ananova.com, researchers used ten radio telescopes in the US to capture radio waves emitted from the hole.
Black holes are created when a dying star collapses under its own gravity. It then sucks in everything around, including light.
The hole that the researchers discovered is as wide as the Earth’s orbit around the sun.

University of Texas scientists have discovered that a protein that causes neurodegenerative effects may, in normal amounts, protect against neurodegeneration, Science daily reported.
The researchers at UT’s Southwestern Medical Center in Dallas said they were surprised by the findings since an excess of the same protein -- alpha-synuclein -- causes Parkinson’s disease.
“It’s the first time that anyone has shown synuclein has any positive function at all in the body, and this is important because it’s been known to be involved in neurodegeneration,“ said Dr. Thomas SÌùdhof, senior author of the study and an investigator at the Howard Hughes Medical Institute.
When mutant mice lack only alpha-synuclein, on the other hand, they continue to appear normal as they age, indicating alpha-synuclein might not be essential in healthy nerve cells. But mice bred to produce an excess of human alpha-synuclein undergo a slowly progressing nerve degeneration resembling Parkinson’s.