玉溪人流要多钱(玉溪做无痛人流哪家医院专业) (今日更新中)

WASHINGTON, July 27 (Xinhua) -- Astronomers studying observations taken by NASA's Wide-field Infrared Survey Explorer (WISE) mission have discovered the first known "Trojan" asteroid orbiting the sun along with Earth, the U.S. National Aeronautics and Space Administration (NASA) announced Wednesday in a statement.Trojans are asteroids that share an orbit with a planet near stable points in front of or behind the planet. Because they constantly lead or follow in the same orbit as the planet, they never can collide with it. In our solar system, Trojans also share orbits with Neptune, Mars and Jupiter. Two of Saturn's moons share orbits with Trojans.Scientists had predicted Earth should have Trojans, but they have been difficult to find because they are relatively small and appear near the sun from Earth's point of view."These asteroids dwell mostly in the daylight, making them very hard to see," said Martin Connors of Athabasca University in Canada, lead author of a new paper on the discovery to be published Thursday in the journal Nature. "But we finally found one, because the object has an unusual orbit that takes it farther away from the sun than what is typical for Trojans. WISE was a game-changer, giving us a point of view difficult to have at Earth 's surface."The WISE telescope scanned the entire sky in infrared light from January 2010 to February 2011. Connors and his team began their search for an Earth Trojan using data from NEOWISE, an addition to the WISE mission that focused in part on near-Earth objects, or NEOs, such as asteroids and comets. NEOs are bodies that pass within 28 million miles (45 million kilometers) of Earth 's path around the sun. The NEOWISE project observed more than 155, 000 asteroids in the main belt between Mars and Jupiter, and more than 500 NEOs, discovering 132 that were previously unknown.The team's hunt resulted in two Trojan candidates. One called 2010 TK7 was confirmed as an Earth Trojan after follow-up observations with the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.The asteroid is roughly 1,000 feet (300 meters) in diameter. It has an unusual orbit that traces a complex motion near a stable point in the plane of Earth's orbit, although the asteroid also moves above and below the plane. The object is about 50 million miles (80 million kilometers) from Earth. The asteroid's orbit is well-defined and for at least the next 100 years, it will not come closer to Earth than 15 million miles (24 million kilometers).

CANBERRA, Sept. 24 (Xinhua) -- Australian scientists on Saturday said a satellite due to re-enter Earth poses a negligible threat to life and property on Earth.U.S. National Aeronautics and Space Administration's Upper Atmosphere Research Satellite (UARS), which weighs more than five tons, is expected to re-enter the Earth's atmosphere at 1058 (AEST) on Saturday. The U.S.-based Center for Orbital and Re-entry Debris Studies estimates that re-entry could occur up to seven hours before or after this time.According to Nonathan Nally, a former editor of two space magazines and currently editor of the Australian Space News website, the satellite poses a negligible threat to life and property on Earth."Most of the satellite will burn up on re-entry, with perhaps as many as 26 stronger or harder small pieces surviving to reach the surface," Nally said in a statement."But with the majority of the Earth comprising oceans or uninhabited (or very sparsely populated) remote regions, the chances are overwhelming that any pieces of UARS that survive re- entry will fall harmlessly and never be seen again."Since the spacecraft is no longer powered, U.S. National Aeronautics and Space Administration has no control over where it comes down, but Nally said there is a small chance that debris from the satellite could land in Australia.Debris from SkyLab, another satellite which plunged to Earth, was scattered over parts of Western Australia in 1979. Skylab weighed about 77 tonnes, many times more than the UARS.?Dr Alice Gorman, a lecturer in the Department of Archaeology, specializing in space archaeology, at Flinders University in South Australia, said the UARS satellite re-entry is very reminiscent of Skylab in 1979."There is the same exaggeration of the hazard through the media, public anxiety as the advance warning allows for speculation, and a lack of understanding of what the risks actually are," he said in a statement."Should it land in Australia, we might expect the same rush for souvenirs as we saw with Skylab, as anything that has been in space has a special meaning on Earth."?UARS was launched on 12 September 1991 and decommissioned on 15 December 2005. Its total dry mass is about 5.5 tonnes. UARS is one of the largest NASA satellites to plunge back to Earth uncontrolled in the last 30 years.Since the beginning of the Space Age in the late-1950s, there have been no confirmed reports of an injury resulting from re- entering space objects.? Nor is there a record of significant property damage resulting from a satellite re-entry.

BEIJING, Sept. 2 (Xinhuanet) -- The amount of space junk orbiting the Earth could cause fatal leaks in spaceships or destroy valuable satellites, according to a report released by the U.S. National Research Council.Computer models have shown that the number of orbital debris "has reached a tipping point, with enough currently in orbit to continually collide and create even more debris, raising the risk of spacecraft failures," the Research Council said Thursday.So far, there are 22,000 pieces of debris large enough to track from the ground, but smaller objects could still cause serious damage.New international regulations are needed to limit space junk.And more researches should be done to test the possible use of launching magnetic nets or giant umbrellas to push the debris further towards the Earth where it would burn up, or into a higher but safer orbit.

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."

CANBERRA, Sept. 9 (Xinhua) -- Australia on Friday launched the first national study to find out whether low to moderate levels of alcohol drank by pregnant women are harmful or not to an unborn child, hoping to provide a clear indication about the safe amount of alcohol for pregnant women.The Murdoch Children's Research Institute in Melbourne, which commissioned the study, is recruiting 2000 pregnant women who will be quizzed throughout their pregnancy about their drinking habits, general health and diets.Their babies will then undergo medical checks, when they turn one and again at two to see if their brains, development and behavior was affected by alcohol consumed by their mums.According to lead researcher associate professor, Jane Halliday, while there was solid evidence about the dangers of heavy drinking for an unborn baby, it was not known if there was a safe amount of alcohol pregnant women could drink.She said the study hoped to shed light on the best approach to alcohol use during pregnancy."The problem is that for about half of women that get pregnant it is unplanned, and a lot of women are drinking around the time they get pregnant and may drink for the first month or so and that creates a lot of anxiety," Assoc Prof Halliday said in a statement."From the few international and Australian studies there's conflicting evidence as to whether there's an adverse effect."We firmly believe that no drinking is the safest option, but our main aim is to provide an evidence base to the policy and answer questions about individual risks."The study came after research by the University of Newcastle published in 2010 revealed 80 percent of Australian women drank during pregnancy.

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