天津龙济医院泌尿科宋金亮天津龙济医院网站,天津武清区龙济医院男子医院割包皮,天津武清龙济医院门诊怎样,天津武清区龙济男科医院信誉如何,天津龙济性功能预约,天津市武清区龙济网址,天津市武清区龙济泌尿科怎么样

BEIJING, Sept. 14 (Xinhuanet) -- Scientists had discovered the fossils of a new species of ancient carnivorous fish, National Geographic reported Monday.The newly-found ancient fish, "Laccognathus embryi", is a 1.8-meter-long predator, which was "waiting to lunge out to grab whatever was in front of it," said study co-author Ted Daeschler, a vertebrate zoologist at the Academy of Natural Sciences in Philadelphia, the U.S..It had a jaw filled with sharp teeth that were 1.5 inches long, the Journal of Vertebrate Paleontology described.The fish lived in the Devonian period, 415 to 360 million years ago, which "was a fish-eats-fish kind of world," Daeschler said. "There was a real arms race going. If you didn't have good armor on your body, you were very vulnerable.""It's not just finding the animal - it's also placing the animal in its evolutionary crucible," Daeschler added.Its closest living relative is the lungfish which can survive in the drought, scientists said.Scientists hope the finding can help in their study on the revolution of fishes as well as other species.

BEIJING, June 21 (Xinhua) -- China will launch a new icebreaker for use during an upcoming 2013 polar expedition, a senior oceanic official said on Tuesday.Both the new icebreaker and Xuelong ("Snow Dragon"), an icebreaker that operated in Antarctica, will form an Arctic-Antarctic maritime research team."China will have at least two icebreakers concurrently operating at both the north and south poles," Chen Lianzeng, deputy director of the State Oceanic Administration, told a national conference on polar research, which has been the first since 1984 when the country started expeditions in polar regions.The new icebreaker will boast facilities that will allow it to research the oceanic environment, integrate data for real-time oceanic monitoring, deploy and retrieve detectors and conduct aerial studies using helicopters, Chen said.The two icebreakers will conduct expeditions in polar regions for more than 200 days annually, he said.Fixed-wing aircraft will also be added to the expedition team before 2015, allowing researchers to be transported between China's Zhongshan and Kunlun research stations and Antarctica's Grove Mountains.The Kunlun station went into operation in early 2009 as the first Chinese research station on Antarctica's inland. The Zhongshan station, established in 1989, now serves as a supply base for the Kunlun station.A written comment by Vice Premier Li Keqiang sent to the conference said the polar research, a magnificent feat of the mankind, has great significance for China's oceanic work and sustainable development."Over the past two decades, China's polar research made great achievements and became influential globally," Li said.Li encouraged Chinese scientists to actively participate in international exchanges and cooperation, safeguard national interests and contribute to the peaceful use of polar regions.Since the early 1980s, China has sent 27 Antarctic expedition teams and completed four research missions to the Arctic Ocean.Besides the Xuelong icebreaker, China has built three Antarctic stations -- Changcheng (Great Wall), Zhongshan and Kunlun -- and one Arctic station -- Huanghe (Yellow River) Station.

WASHINGTON, July 7 (Xinhua) -- Space shuttle Atlantis will soar into the sky Friday on NASA's 135th and final flight. Its scheduled return to Earth later this month will mark the end of NASA's 30-year space program.Since its onset with the launch of space shuttle Columbia, the program has been seen as a cheap, safe and reliable way for space exploration.Despite its great contributions to U.S. manned space flight, it has also left some grave and tragic lessons, making its termination inevitable.HIKING COSTSLaunched in 1972 by then President Richard Nixon, the shuttle program aimed to provide a new system of affordable space travel and proved to be NASA's most enduring project in its 50 years of existence.In 1981, shuttle Columbia made its first shuttle flight for two days. It was the ultimate hybrid and the first reusable spacecraft.Launched like a rocket and gliding back to Earth like an airplane, space shuttles not only can act as a space taxi to carry astronauts, but have the muscle of a long-distance trucker to haul heavy machinery.The spaceship boasts more than 3,500 subsystems and 2.5 million parts and is nine times faster than a speeding bullet as it climbs heavenward. That versatility, however, has translated into higher costs.NASA originally estimated the program would cost about 90 billion U.S. dollars. However, its actual cost stands at about 200 billion dollars, compared with the 151 billion dollars spent on Apollo which took Americans to the moon in 1969.In an article in Technology Review, John Logsdon, former head of the Space Policy Institute at George Washington University, drew a direct connection between the ravenous shuttle budget and the lack of other large advances in manned space flight."By operating the system for 30 years, with its high costs and high risk, rather than replacing it with a less expensive, less risky second-generation system, NASA compounded the original mistake of developing the most ambitious version of the vehicle," he wrote."The shuttle's cost has been an obstacle to NASA starting other major projects," he added.HIGH RISKIn terms of safety, the shuttles have never been as reliable as their designers had envisioned.On average, one out of every 67 flights ended up with fatal accidents. Based on the rate of deaths per million miles traveled, the space shuttle is 138 times riskier than a passenger jet.Seven astronauts onboard died when Challenger exploded about a minute after launch in 1986. Nearly two decades after the tragic blast, a new catastrophe descended when the shuttle Columbia disintegrated moments before landing in 2003, killing another seven spacemen.Again, the shuttle program was shelved for more than two years as NASA stepped up efforts to make it safer. But experts say the fundamental problem related to shuttles' safety cannot be solved due to their "birth defects.""It is in the nation's interest to replace the Shuttle as soon as possible," concluded the panel that investigated the 2003 Columbia accident.

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).

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.