中山肛肠多少钱啊(中山肛门附近肿肉) (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. 30 (Xinhuanet) -- Heading football frequently may cause brain damage leading to subtle but serious declines in thinking and coordination skills, a new study suggested as quoted by media reports Wednesday.Researchers used an advanced MRI (Magnetic Resonance Imaging) technique to analyze changes in brain white matter of 32 adult amateur soccer players who head balls 436 times a year on average.The study found players who head football quite frequently -- with 1,000 or more a year -- showed abnormalities similar to traumatic brain injuries suffered in car accidents."This is the first study to look at the effects of heading on the brain using sophisticated diffusion tensor imaging," said Dr. Michael Lipton, a leading researcher and associate director of the Gruss Magnetic Resonance Research Center at the Albert Einstein College of Medicine in New York City."We found the real implication for players isn't from hitting headers once in a while, but repetitively, which can lead to degeneration of brain cells," he added.The researchers compared neurological images of study participants, whose average age was 31, and found those with the highest volume of headers had abnormalities in five areas of the brain, responsible for attention, memory, physical mobility and high-level visual functions.The findings come in the wake of mixed reports on the so-called "cognitive" consequences of frequently heading soccer balls at practice.Dr. Chris Koutures, a pediatrician and sports medicine specialist in Anaheim Hills, California, said the retrospective imaging study was fascinating, but needs more data to effectively determine safe header limits, especially for younger players.Dr. Lipton agreed neuropsychological damage from headers would be hard for a coach or physician to notice since cognitive problems develop gradually, and even players might not be aware of mild memory loss."We can't tell an individual today not to be heading a ball, but caution is a good thing," Lipton said. "We need more research for definitive answers and we have the advanced imaging tools to do it."

PARIS, Oct. 15 (Xinhua) -- Faced with new problems such as sovereign debt and downward risks, all countries should work together to enhance coordination on macroeconomic policies to guard economic growth and financial stability with respective effort, Chinese delegates said Saturday here at the G20 Financial Ministers Meeting.The global economy is challenged by new difficulties which require all countries to join hands in fighting all sorts of protectionism either in trade or in investment, according to a statement issued by the Chinese delegation led by Chinese Financial Minister Xie Xuren and Central Bank Governor Zhou Xiaochuan.China suggested that leading developed countries should ensure economic recovery and financial stability in short term, while in the medium term enhance fiscal solidarity, accelerate structural reform and refrain the negative impact of macroeconomic policies.Meanwhile, China also stressed that the emerging countries should make their own contribution to tackle the problems. "The emerging markets should promptly take flexible and effective macroeconomic measures in order to control slowdown and tackle with impacts from inflation and capital flows," the statement said.Emerging economies "should also quicken their pace on structural reform in a bid to realize stable and faster growth," the statement added.During the two-day meeting, G20 financial leaders gathering in Paris welcomed the progress the Europe made on the eurozone debt issue on Saturday, but meanwhile expected the euro area to rely more on itself with bigger bailout fund to avoid contagion.

BEIJING, Jan. 8 (Xinhua) -- China started the Spring Festival peak travel season Sunday, with tens of millions of passengers, mainly migrant workers and college students, on the move in the world's largest seasonal migration.The Spring Festival, or Chinese Lunar New Year, fall on Jan. 23 this year. It is the most important traditional Chinese festival for family reunions.A total of 3.16 billion passenger trips are expected during the 40-day peak travel season, or Chunyun (Spring transportation) in Chinese, up 9.1 percent from a year earlier, according to the National Development and Reform Commission.

WASHINGTON, Dec. 7 (Xinhua) -- The use of two drugs never tried in combination before in ovarian cancer resulted in a 70 percent destruction of cancer cells already resistant to commonly used chemotherapy agents, say researchers at Mayo Clinic in Florida.Their report, published on-line Wednesday in Gynecologic Oncology, suggests that this combination, ixabepilone and sunitinib, might offer a much needed treatment option for women with advanced ovarian cancer.Neither drug is approved for use in ovarian cancer. Ixabepilone is a chemotherapy drug that, like other taxane drugs, targets the microtubules and stops dividing cells from forming a spindle. It has been approved for use in metastatic breast cancer. Sunitinib, approved for use in kidney cancer, belongs to a class of tyrosine kinase inhibitors that stops growth signals from reaching inside cancer cells.When caught at late stages, ovarian cancer is often fatal because it progressively stops responding to the chemotherapy drugs used to treat it."Women die from ovarian cancer because their tumors become resistant to chemotherapy, so a drug that might be able to reduce that resistance -- which may be what this combination of agents is doing -- would be a boon to treatment of this difficult cancer," says study coauthor Gerardo Colon-Otero.The finding also highlights the importance of the role of a molecule, RhoB, that the researchers say is activated by the drug duo. It might be a potential biomarker that may help identify patients who might benefit from such combination therapy, the researchers say.

来源：资阳报