梅州打胎术前注意什么(梅州什么时间适合打胎) (今日更新中)

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.

BEIJING, Nov. 26 (Xinhua) -- Joint police patrols along the Mekong River will kick off in mid December to restore security after a deadly attack to Chinese ships in October.Chinese police will start patrols along the river with Laos, Myanmar and Thailand, said a statement from the Ministry of Public Security here Saturday.No exact date was given, but the first joint patrol will be carried out before Dec. 15, said the statement, issued after a ministerial meeting of four countries held in Beijing.Police from the four will work together to restore shipping and guarantee security along the river, the statement said.Shipping on the Mekong River has been suspended since two cargo ships were attacked on Oct. 5, resulting in the murder of 13 Chinese sailors.A headquarters for the initiative will be founded in China and there will be a coordination office in each of the other three countries. They will be linked by a round-the-clock communication mechanism, the statement said.China will assist Laos and Myanmar police in terms of training and equipment, the statement said.Police departments of the four countries will also set up a coordination team to work out more security measures along the Mekong River, it added.

XI'AN, Nov. 20 (Xinhua) -- Fish in Hongjiannao Lake, China's largest desert freshwater lake, are teetering on the verge of extinction, according to local fishery authorities."The fish in Hongjiannao have nearly vanished," said Li Weiping, the head of a fish monitoring station in northwest China's Shaanxi province.As the lake continues to shrink, its water has become more salty and its pH reading has reached 9.6, while the maximum reading suitable for fish is 8.5, according to Li.The lake has gradually lost the water that it used to get from underground streams and rivers, Li said, adding that excessive coal mining around the lake has changed the way water flows underground. Two reservoirs have been built on two rivers near the upper reaches of the lake, preventing river water from flowing into the lake.The lake's water level has plunged by 20 to 30 centimeters every year. Its total surface area has been reduced to 41.8 square km, down from 67 km in 1996.

BEIJING, Jan. 1 (Xinhua) -- Chinese President Hu Jintao and his South Korean counterpart Lee Myung-bak exchanged new year greetings Sunday and announced the start of the "China-South Korea Friendly Exchange Year".In his message, Hu spoke positively of the relations between the two countries. Seizing the opportunity of the 20th anniversary of the establishment of the China-South Korea diplomatic relations, China is willing to work together with South Korea, by launching various exchange programs, to further promote mutual understanding and friendship between the two peoples, deepen communication and cooperation in all sectors, and push for constant progress of the bilateral relationship, Hu said.For his part, Lee said on the basis of the accomplishments achieved over the two decades of the bilateral diplomatic ties, South Korea looks forward to joining hands with China to build a better future for the bilateral relationship.

来源：资阳报