中山肠息肉的主要症状(中山肛肠科医院超好的大夫) (今日更新中)

WASHINGTON, Sept. 13 (Xinhua) -- The U.S. Department of Agriculture (USDA) announced Tuesday it will begin testing next year for six more kinds of E.coli bacteria in raw ground beef and tenderized steaks in order to protect the safety of the American food supply.The U.S. currently tests for one strain of E.coli O157:H7 in beef. According to the USDA, from March 5 next year, if the E. coli serogroups O26, O103, O45, O111, O121 and O145 are found in raw ground beef or its precursors, those products will be prohibited from entering commerce.Like E.coli O157:H7, these serogroups can cause severe illness and even death, and young children and the elderly are at highest risk."The Obama Administration is committed to protecting our food supply and preventing illnesses before they happen," said Agriculture Secretary Tom Vilsack in a statement. "Today's announcement does exactly that by targeting and eliminating contaminated products from the market.""Too often, we are caught reacting to a problem instead of preventing it. This new policy will help stop problems before they start," he said.About one in six Americans becomes sick from a food borne illnesses each year, an epidemic that kills about 3,000 annually and hospitalizes 128,000, according to the U.S. Centers for Disease Control and Prevention.

RIO DE JANEIRO, Sept. 26 (Xinhua) -- Rio de Janeiro has the highest level of air pollution in Brazil, and is more polluted than many other world metropolis like New York, London and Paris, a World Health Organization (WHO) study said Monday.According to the study, which was carried out in 91 countries and regions, the air in Rio's metropolitan area contains 64 micrograms of fine particulate matter per cubic meter, over three times the upper limit set by the WHO, which is 20 micrograms per cubic meter.Despite being larger, having a bigger population and more vehicles, Sao Paulo's metropolitan area has less air pollution, with 38 micrograms of fine particulate matter per cubic meter.According to the WHO, "the largest contributors to urban outdoor air pollution include motor transport, small-scale manufacturers and other industries, burning of biomass and coal for cooking and heating, as well as coal-fired power plants." The organization said that residential wood and coal burning for heating also help increase air pollution, especially in rural areas in the cold months.The WHO expressed concern over air pollution levels in several cities, as some two million people worldwide die annually from conditions resulting from air pollution."Air pollution is a major environmental health issue, and it is vital that we increase efforts to reduce the health burden it creates," said Dr. Maria Neira, WHO's director for Public Health and Environment.According to the study, Ahwaz, Iran, has the most polluted air in the world, with 372 micrograms of fine particulate matter per cubic meter.

SAN FRANCISCO, Sept. 2 (Xinhua) -- A late-season potato blight has been detected on farms in Alaska, only the fourth time the disease appear in the U.S. state since 1995, local media reported on Friday.The disease was found this week in the fields of potato producers in cities of Delta Junction and Palmer, according to the Fairbanks Daily News-Miner, Alaska's second largest daily newspaper.Farmers in both fields are working to prevent the spread of the blight, a fungus-like disease that can kill plants in the field or cause potatoes to rot in storage, the newspaper reported.Growers have been asked to kill all affected plants within 100 feet, and plant samples from both sites will be examined to identify what type of late blight is involved.Experts said that blight can be controlled through the use of fungicides, but the cool, damp weather this summer in the areas has created an ideal environment for the disease to spread.Although Alaska's potato crop is tiny compared to other U.S. states, it has been viewed as a possible global source of seed potatoes in recent years because it is largely free of disease.A local university has explored partnerships with Chinese growers to export certified seed potatoes, noted the Fairbanks Daily News-Miner report.

BEIJING, Sept. 26 (Xinhuanet) -- Weather forecasts showed that Thursday or Friday might be suitable for launching the Tiangong-1 spacecraft, experts said.The unmanned spacecraft, part of China's first spacecraft rendezvous and docking mission, was set to blast off from the Jiuquan Satellite Launch Center in Northwest China at an appropriate time between Tuesday and Friday.But the latest weather forecast showed that Tuesday and Wednesday would not be suitable for a launch, Cui Jijun, chief commander of the mission's launch site system, was quoted by China National Radio as saying on Sunday.A precondition for launching is that the average wind speed at the launch site should not be faster than 10 meters a second. The upper-level wind, at 300 meters to 25,000 meters above the Earth, should be no faster than 70 meters a second.The 8.5-ton Tiangong-1 spacecraft and the Long March II-F rocket stand at the Jiuquan Satellite Launch Center on Sept 20. The spacecraft is set to blast off at an appropriate time between Tuesday and Friday.If the wind is too strong, the rising rocket carrier could wiggle and pose a danger, experts said."Everything is ready now except for the right weather," Cui said.On Sunday afternoon, all systems of the Tiangong-1 project went through a joint maneuver, he said. Before that, the 8.5-ton spacecraft, and the Long March II-F rocket that will carry it skyward, were positioned onto the launch pad last Tuesday.Engineers carried out checkups on the conditions of the rocket and the spacecraft, among many other tests in the past few days. All preparation work is done except for fuel loading, he said.Wang Xiaoqing, a publicity official at the launch site, said that the fuel loading usually begins one day before the launch. Once the fuel is loaded into the carrier vehicle, the launch becomes "irreversible".Tiangong-1, or Heavenly Palace 1, will serve as "a target spacecraft" for three rendezvous and docking experiments.The spacecraft rendezvous and docking missions are expected to pave the way for the building of a planned space station scheduled for 2020, previous reports said.Following Tiangong-1, an unmanned Shenzhou VIII spaceship will blast off from the Jiuquan Satellite Launch Center later this year.Lu Jinrong, chief engineer of the mission's launch site system, said that it is rare that two launches of China's manned space program are scheduled in half a year."In the past, the launch site carried out one launch a year, or even one every two to three years," he said."We are already in a high-frequency launch period."

Beijing, Sept. 6 (Xinhua) -- A sperm donation scandal disclosed recently has aroused growing concern in the United States.According to the New York Times' report, Ryan Kramer, the son of a donor, found that he has more than 150 half-siblings - they are all the children of the same donor."It's wild when we see them all together - they all look alike," said Cynthia Daily, mother of Kramer.As more women choose to have children on their own, the demand for sperm donors has surged.Some sperm banks are earning huge profits by allowing too many mothers to receive sperms from the same popular donors, according to the report.And this trend will lead to risks: rare genetic diseases could be spread more widely, and the children of the same donor could meet and, unbeknownst to them, commit incest, medical experts warned.Parents and donors are calling for a tighter regulation so that donor children can know more about their donors, and the number of kids from each donor can be limited.

来源：资阳报