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WASHINGTON, Jan. 2 (Xinhua) -- A systematic review of previous studies suggests that there may be a positive connection between physical activity and children's academic performance, according to a report published Monday in the Archives of Pediatrics & Adolescent Medicine.A group of scientists at the Vrije Universiteit (Free University) Medical Center in the Netherlands reviewed evidence on the relationship between physical activity and academic performance because of concerns that pressure to improve test scores may often mean more instructional time for classroom subjects with less time for physical activity.The authors identified 10 observational and four interventional studies for review, 12 of which were done in the United States, one in Canada and one in South Africa. Sample sizes ranged from 53 to about 12,000 participants between the ages of eight years and 18 years old. Follow-up varied from eight weeks to more than five years."According to the best-evidence synthesis, we found strong evidence of a significant positive relationship between physical activity and academic performance. The findings of one high-quality intervention study and one high-quality observational study suggest that being more physically active is positively related to improved academic performance in children," the report said.Background information in the article suggests that exercise may help cognition by increasing blood and oxygen flow to the brain, increasing levels of norepinephrine and endorphin to decrease stress and improve mood, and increasing growth factors that help create new nerve cells and support synaptic plasticity."More high-quality studies are needed on the dose-response relationship between physical activity and academic performance and on the explanatory mechanisms, using reliable and valid measurement instruments to assess this relationship accurately," the report concluded.

PHNOM PENH, Oct. 3 (Xinhua) -- Cambodia reported on Monday that some 54 Cambodian children had been killed by dengue fever in the first nine months of this year, compared to 37 kids dying of the disease in the whole year of 2010.From January to September this year, some 12,392 cases of dengue fever had been reported with 54 children killed by the disease. The whole year 2010 reported only 5,497 cases, Ngan Chantha, director of dengue control at the Ministry of Health, said on Monday."This year's rainy season has been plagued by floods, leading to more cases of the disease," he said. "I would like to appeal to parents to let their children sleep under mosquito nets and if their kids have any symptom that is suspicious of the disease, they should urgently send them for medical attention."Dengue is caused by mosquitoes. The disease causes an acute illness of sudden onset that usually follows symptoms such as headache, fever, exhaustion, severe muscle and joint pain, swollen glands and rash.In Cambodia, the outbreak of dengue fever usually begins at the onset of the rainy season from May to October. 

ADDIS ABABA, Nov. 15 (Xinhua) -- The African Union (AU) Commission Chairperson Jean Ping on Tuesday met and held talks with a high level Chinese delegation led by Jiang Yaoping, Chinese Vice Minister of Commerce.The discussion between the two sides was mainly focused on the cooperation between China and Africa in different sectors.Ping said AU is ready to do all possible to further strengthen its ties with China.The Chairperson said China has been working in cooperation with AU member states on various areas, including trade, investment, and diplomatic exchanges."We are happy to meet the delegation; a delegation not only as an important partner but as a friend of Africa, a friend with which we are strengthening cooperation constantly," said the Chairperson.He also reiterated that Africa is benefited from the relations with China.He said Africa has established an important relations with China within the China-Africa Cooperation Forum (FOCAC), and the two sides are now engaged in strategic dialogue on very crucial areas.Jiang said that AU has been committed to economic integration in Africa that enable member states improve the livelihoods of Africans.He also said that AU has played a constructive role in meeting global issues like the climate change.The Vice Minister stated that China has become one of the most trading partner of Africa, and the trade volume between China and Africa is increasing from time to time.Leading the delegation, Jiang has also visited the African Union Conference Center (AUCC) Project which is almost completed and is expected to be the avenue of the coming AU Summit for the first time at its own headquarter.

WASHINGTON, Sept. 30 (Xinhua) -- At least 15 people have been killed amid 84 sickened in 19 states in listeria outbreak traced to Colorado cantaloupes, making it the most deadly U.S. outbreak of food-borne infection since 1998, the Centers for Disease Control and Prevention (CDC) said Friday.Of the 15 victims, five were in New Mexico, three in Colorado, two in Texas, and one each in Kansas, Maryland, Missouri, Nebraska and Oklahoma. Health departments in Wyoming and Kansas have said they are investigating additional deaths that may be connected to the outbreak.The previous toll announced on Tuesday was 13 dead and 72 sick.The Food and Drug Administration on Sept. 14 warned consumers not to eat cantaloupes from Colorado's Rocky Ford region shipped by Jensen Farms. The cantaloupes with the brand name Rocky Ford were distributed from July 29 to Sept. 10 in at least 17 states."Even if some of the cantaloupe has been eaten without becoming ill, dispose of the rest of the cantaloupe immediately. Listeria bacteria can grow in the cantaloupe at room and refrigerator temperatures," the CDC said.Listeria is a common bacterium that typically causes mild illness in healthy people, but can cause severe illness in older people and those with compromised immune systems. It also can cause miscarriages and stillbirths in pregnant women and severe infections in new babies.Listeria infections lead to about 1,600 serious illnesses each year and about 260 people die, according to the CDC.The CDC estimates that about 48 million people in the U.S. each year get sick from tainted food, with about 128,000 hospitalized and 3,000 deaths.

JIUQUAN/BEIJING, Nov. 1 (Xinhua) -- Commander-in-chief of China's manned space program Chang Wanquan announced early Tuesday that the launch of Shenzhou-8 unmanned spacecraft was successful.The spacecraft was sent into the designated orbit after the blastoff at 5:58 a.m. from the Jiuquan Satellite Launch Center in northwest Gobi desert, carried by an upgraded Long March-2F rocket.It is heading for rendezvous with Tiangong-1, or "the Heavenly Palace" that was put into space on Sept. 29 for the country's first space docking.The move, if successful, will pave the way for China to operate a permanent space station around 2020 and make the nation the world's third to do so.The combined photo taken on Nov. 1, 2011 shows the blast-off of a modified model of the Long March CZ-2F rocket carrying the unmanned spacecraft Shenzhou-8 at the Jiuquan Satellite Launch Center in northwest China's Gansu Province. Commander-in-chief of China's manned space program Chang Wanquan announced that the launch of the spacecraft was successful.Chinese Vice Premier Zhang Dejiang viewed the launch at the Jiuquan center. The launch was also observed on site by senior officials from the European Space Agency and the German Aerospace Center.The docking is scheduled to occur within two days after the launch of Shenzhou-8 and at a height of 343 km above the Earth's surface. It will return to the Earth after two docking tryouts.Chinese and German scientists will conduct 17 life science space experiments on the Chinese spacecraft Shenzhou-8, Wu Ping, spokeswoman for China's manned space program, said Monday.To ensure the success of the mission, Chinese space engineers have made "considerable modifications" on Shenzhou-8 to previous versions of the spacecraft.Shenzhou-8, with a length of nine meters and a maximum diameter of 2.8 meters, has a liftoff weight of 8.082 tonnes."More than half of the 600 or so sets of equipment have been modified, while newly designed devices account for about 15 percent of the total," Wu said.The modifications were mainly aimed at arming the spacecraft with automatic and manual rendezvous and docking capacities, and enhancing the vehicle's performance, safety and reliability, Wu said."After the improvements, the spacecraft will be able to connect with the target spacecraft Tiangong-1 for 180 days," Wu said.The unmanned spacecraft is also equipped with devices for recording real images and mechanical parameters during its flight, to test the space docking before a manned attempt.Once China has mastered the technologies of rendezvous and docking, it will be equipped with the basic technologies and capacity required for building a space station, said Zhou Jianping, chief designer of China's manned space program.Tuesday's mission will be followed by launches of spaceships Shenzhou-9 and -10 in 2012, which are also expected to dock with Tiangong-1. "At least one mission of the two will be manned," Wu said.The crew members, including probably two female astronauts, have already been selected for the possible manual space docking mission in 2012 and are being trained for manual docking skills.The space docking tests and experiments will provide crucial experience of China's construction of a 60-tonne permanent manned space station around 2020 when Chinese astronauts are expected to operate more research projects in space."It will make it possible for China to carry out space exploration of a larger scale," Zhou said.