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BEIJING, July 26 (Xinhuanet) -- Hong Kong scientists announced that they had determined the idea of time travel is impossible by proving nothing can travel faster than the speed of light.The finding is contained in a study done by a research team from Hong Kong University of Science and Technology. The study was published Monday in a scientific journal "Physical Review Letters" in the United States."The study, which showed that single photons also obey the speed limit c, confirms Einstein's causality, that is, an effect cannot occur before its cause," the university said on its website."By showing that single photons cannot travel faster than the speed of light, our results bring a closure to the debate on the true speed of information carried by a single photon." said Professor Du Shengwang, who led the study.The possibility of time travel was raised 10 years ago when scientists discovered the optical pulses in some specific medium might propagate information in a faster-than-light speed."Our findings will also likely have potential applications by giving scientists a better picture on the transmission of quantum information." Du said.

THE HAGUE, June 24 (Xinhua) -- Bird flu was discovered at a poultry farm in the central Dutch province of Flevoland, the Ministry of Agriculture said Friday.It said the virus discovered was a mild variant. The farm's 47,000 chickens were slaughtered to prevent the virus turning into a contagious and deadly variant.It remains uncertain whether the chickens were infected with the high or low pathologene H7 variant. The low pathologene version can mutate into a high pathologen, which is extremely transmittable.Poultry from other farms in a zone of three kilometres of the contaminated farm will be tested. A prohibition of transport for poultry, eggs and poultry manure has been set.

SAN FRANCISCO, Sept. 12 (Xinhua) -- More U.S. Internet users will access Internet through mobile devices than through PCs or other wireline devices by 2015, market research company International Data Corporation (IDC) said in its latest study released on Monday.According to IDC, the number of mobile Internet users will grow by a compound annual growth rage of 16.6 percent between 2010 and 2015, as mobile devices sales, such as smartphones and media tablets, explode."The impact of smartphone and especially, media tablet adoption will be so great that the number of users accessing the Internet through PCs will first stagnate and then slowly decline," said IDC in a forecast.Western Europe and Japan will not be far behind the U.S. in following this trend, the study noted.IDC also predicts that some 40 percent of the world's population will have access to Internet in 2015, when the total number of Internet users will grow to 2.7 billion from 2 billion in 2010."Forget what we have taken for granted on how consumers use the Internet," Karsten Weide, IDC's research vice president of media and entertainment, said in a statement."Soon, more users will access the Web using mobile devices than using PCs, and it's going to make the Internet a very different place," he added.

BEIJING, July 19 (Xinhuanet) -- Lifestyle changes such as exercise, eating healthily and not smoking could reduce the chances of having Alzheimer’s disease by half, researchers said in a study quoted by news reports Tuesday.Hundreds of thousands of patients could potentially avoid the devastating illness by simply changing bad habits, according to the study published in the journal Lancet NeurologyFor the first time, scientists have calculated the extent to which certain lifestyle traits -- including lack of exercise, smoking and obesity -- all contributed to the disease.Researchers found that in the Western world, an inactive “couch potato” lifestyle was the most important possible cause.Smoking, obesity in middle-age, high blood pressure and diabetes all increased the risk as they cause damage to blood vessels in the brain, leading to death of brain cells. Together, the modifiable risk factors contributed to 50 percent of Alzheimer’s cases worldwide.The researchers want to carry out more work to find out how many people can prevent the disease by making small changes to their lifestyle.

WASHINGTON, June 23 (Xinhua) -- NASA's next Mars rover has completed the journey from its California birthplace to Florida in preparation for launch this fall, the U.S. space agency said Thursday in a statement.The Mars Science Laboratory (MSL) rover, also known as Curiosity, arrived Wednesday at NASA's Kennedy Space Center aboard an Air Force C-17 transport plane. It was accompanied by the rocket-powered descent stage that will fly the rover during the final moments before landing on Mars.The rover's aeroshell -- the protective covering for the trip to the Red Planet -- and the cruise stage, which will guide it to Mars, arrived at Kennedy last month. The mission is targeted to launch from Cape Canaveral Air Force Station between Nov. 25 and Dec. 18. The car-size rover will land on Mars in August 2012.The rover and other spacecraft components will undergo more testing before mission staff stack them and fuel the onboard propulsion systems. Curiosity should be enclosed in its aeroshell for the final time in September and delivered to Kennedy's Launch Complex 41 in early November for integration with a United Launch Alliance Atlas V rocket.Curiosity is about twice as long and more than five times as heavy as any previous Mars rover. Its 10 science instruments include two for ingesting and analyzing samples of powdered rock delivered by the rover's robotic arm. During a prime mission lasting one Martian year -- nearly two Earth years -- researchers will use the rover's tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed.