郑州河南可以进行眼部激光手术的医院(郑州近视眼怎么治好) (今日更新中)

BEIJING, Sept. 23 (Xinhua) -- A defunct U.S. satellite is expected to crash down to Earth Friday, with nobody knowing where or when exactly it will hit. This was avoidable, a Chinese expert said Thursday.Pang Zhihao, a researcher from the Chinese Research Institute of Space Technology, told Xinhua that the crash could have been avoided had the satellite been put into a higher orbit, or manipulated to drop in the South Pacific when it had abundant fuel. It would pose no threat to Earth if these measures had been taken.NASA's tumbling, 5,900 kg Upper Atmosphere Research Satellite, or UARS, is the first of such man-made space vehicles that have been launched into outer space according to the agency's Mission to Planet Earth. The mission was launched in the 1990s.The mission is designed to provide data for better understanding Earth's upper atmosphere and the effects of natural and human interactions on the atmosphere.The satellite was deactivated in 2005 as it ran out of fuel and was left orbiting Earth like a big piece of space junk.There are other cases of defunct satellites. The European Space Agency said earlier its observation satellite ERS-2 has run out of fuel and is deorbiting. It would therefore also crash sooner or later.Pang said all countries which are operating space vehicles should take care of their own spacecrafts so that they won't pose any danger.The expert also said that the public need not worry too much.Pang said most spacecrafts will be incinerated upon re-entering Earth's atmosphere, and the debris will mostly likely fall into the ocean or hit an uninhabited area. In addition, a debris tracker is able to give a comparatively accurate prediction where the craft will fall about two hours before it hits Earth, giving residents, if there are any, time to evacuate.He added that there are several ways to minimize the threat of decommissioned spacecrafts, like putting them into higher orbits and crashing them into designated waters.Scientific progress would possibly bring about more ways of dealing with tumbling satellites. Scientists have already been trying to build spacecrafts with degradable materials so that they can self-destruct when re-entering Earth's atmosphere.

BEIJING, July 25 (Xinhuanet) -- More than one in three births in the U.S. are  delivered by C-section, which is an all time high and an increase of 25 percent over seven years, according to news reports Monday quoting a new study.Based on data from 19 states, C-section, or Cesarean, deliveries shot up from 27 percent of all births in 2002 to 34 percent in 2009, said the study by HealthGrades.  HealthGrades is an independent health care ratings organization with information on physicians, dentists and 5,000 hospitals in the nation.The study noted that the states with the highest rates are Texas, New Jersey and Florida while Utah, Colorado and Wisconsin are the lowest.Experts hold C-section deliveries are most suitable when vaginal delivery puts the health of the woman or child at risk, but also attributing the reason of increase to convenience, less risk, fertility and general attitudes.However, Divya Cantor, MD, MBA and HealthGrades Senior Physician Consultant. cautioned, "C-sections are rising, and there needs to be a little bit more scrutiny from the person who is having the C-section as well as doctors and hospitals."

BEIJING, Sept. 20 (Xinhua) -- Floods and landslides triggered by recent heavy rains in eight of China's provincial-level regions have left 70 people dead and 32 others missing this month.Heavy downpours, floods and other related disasters have affected Sichuan, Shaanxi, Henan, Chongqing, Hubei, Shandong, Shanxi and Gansu, the National Disaster Reduction Commission said in a statement released on Tuesday.As of Tuesday, these disasters have affected 21.56 million people and caused an estimated 26.09 billion yuan (4.08 billion U.S. dollars) in direct economic losses, the statement said.

BEIJING, July 11 (Xinhuanet) -- Gay and bisexual men account for around one in every three new cases of HIV in China, according to the latest official statistics released by the Ministry of Health.About 5 percent of the group - officially termed men who have sex with men, or MSM - are living with the virus, which is a rate that is 88 times higher than the national HIV prevalence rate of 0.057 percent.The problem is particularly acute in large urban centers, with the prevalence rate in some southwestern cities reaching almost 20 percent.However, the statistics also show that less than half of all gay and bisexual men have access to HIV screening, while about 15 percent of those who are infected are not receiving treatment."Cities are at the heart of China's development and progress and must remain at the forefront of its HIV response," said Michel Sidibe, executive director of the Joint United Nations Programme on HIV/AIDS (UNAIDS), during a workshop about the HIV impact on MSM on Saturday in Chengdu, capital of Southwest China's Sichuan province."Through bold action cities can lead the way to achieving the UNAIDS vision of zero new HIV infections, zero discrimination and zero AIDS-related deaths," he said, according to a UNAIDS news release. "We hope that over the next year, many more Chinese cities will implement MSM strategies."Almost 10 percent of gay and bisexual men in Chengdu are HIV-positive, according to Yang Xiaoguang, director of the city's health bureau. He agreed with Sidibe that cities have a crucial role to play in AIDS prevention and added: "By working to build a strong, multi-sector response in Chengdu, with meaningful community participation, we can scale-up coverage of prevention, treatment and care services among MSM and halt the spread of HIV."During the workshop, senior Chinese health officials, representatives from civil societies and other delegates discussed a new five-year strategy that increases coverage of HIV prevention and treatment for the MSM population and promotes the participation of community organizations.Government estimates put China's population of gay men at between 5 and 10 million, although Zhang Beichuan, a leading expert on HIV at Qingdao University, puts the number closer to 30 million.Tong Ge, coordinator of China's MSM Health Forum, noted the importance of ensuring strong cooperation between the government and society."By building on the experiences of cities like Chengdu, which already have well developed AIDS responses, we can help promote multi-sector collaboration on an equal, orderly basis and strengthen the response to HIV nationwide," he said. "The next step will be to implement similar strategies in other cities nationwide."Chengdu's new strategy underscores the critical role community organizations can play in reaching MSM and other populations at a higher risk of infection, experts at the workshop said.In 2009, China had an estimated 740,000 people living with HIV/AIDS, according to UNAIDS statistics.

来源：资阳报