济南中药治阳痿早泄方(济南多长时间阴虱) (今日更新中)

WASHINGTON, Aug. 31 (Xinhua) -- Astronomers using NASA's Chandra X-ray Observatory discovered the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way, NASA announced Wednesday.Approximately 160 million light years from Earth, the pair is the nearest known such phenomenon.The black holes are located near the center of the spiral galaxy NGC 3393. Separated by only 490 light years, the black holes are likely the remnant of a merger of two galaxies of unequal mass a billion or more years ago.Both of the supermassive black holes are heavily obscured by dust and gas, which makes them difficult to observe in optical light. Because X-rays are more energetic, they can penetrate this obscuring material. Chandra's X-ray spectra show clear signatures of a pair of supermassive black holes."If this galaxy weren't so close, we'd have no chance of separating the two black holes the way we have," said Pepi Fabbiano of the Harvard-Smithsonian Center for Astrophysics, who led the study that appeared Wednesday in on-line issue of the journal Nature. "Since this galaxy was right under our noses by cosmic standards, it makes us wonder how many of these black hole pairs we've been missing."Previous observations in X-rays and at other wavelengths indicated that a single supermassive black hole existed in the center of NGC 3393. However, a long look by Chandra allowed the researchers to detect and separate the dual black holes. Both black holes are actively growing and emitting X-rays as gas falls towards them and becomes hotter.When two equal-sized spiral galaxies merge, astronomers think it should result in the formation of a black hole pair and a galaxy with a disrupted appearance and intense star formation. A well-known example is the pair of supermassive black holes in NGC 6240, which is located about 330 million light years from Earth.However, NGC 3393 is a well-organized spiral galaxy, and its central bulge is dominated by old stars. These are unusual properties for a galaxy containing a pair of black holes.

WASHINGTON, Aug. 11 (Xinhua) -- The unique fossils of an adult plesiosaur and its unborn baby may provide the first evidence that these ancient animals gave live birth like mammals, according to a new study to be published Friday in the journal Science.The 78-million-year-old, 15.4-foot-long (4.7-meter-long) adult specimen is a Polycotylus latippinus, one of the giant, carnivorous, four-flippered reptiles that lived during the Mesozoic Era.Dr. Robin O'Keefe of Marshall University in West Virginia and Dr. Luis Chiappe, Dinosaur Institute director of the Natural History Museum in Los Angeles County, have determined that it is the fossil of an embryonic marine reptile contained within the fossil of its mother.The embryonic skeleton contained within shows much of the developing body, including ribs, 20 vertebrae, shoulders, hips, and paddle bones.O'Keefe and Chiappe have also determined that plesiosaurs were unique among aquatic reptiles in giving birth to a single, large offspring, and that they may have lived in social groups and engaged in parental care.Although live birth has been documented in several other groups of Mesozoic aquatic reptiles, no previous evidence of it has been found in the important order of plesiosaurs."Scientists have long known that the bodies of plesiosaurs were not well suited to climbing onto land and laying eggs in a nest," O'Keefe said."So the lack of evidence of live birth in plesiosaurs has been puzzling. This fossil documents live birth in plesiosaurs for the first time, and so finally resolves this mystery."

LOS ANGELES, Sept. 1 (Xinhua) -- Fisker Automotive, a Southern California electric car maker, announced on Thursday that it has signed a pact with BMW regarding the supply of engines and other related components for future models in a major tieup.The Anaheim, Orange County-based U.S. car maker will get a four-cylinder turbocharged engine, totalling 100,000 units every year, for its next generation of cars under a project code-named "Project Nina," the company said.The production of the model, a mass-market plug-in hybrid sedan, will begin at the end of 2012 and the sale is slated for 2013."The BMW engine was an obvious choice for us, as BMW is known for producing the best and most fuel efficient gasoline engines in the world," Fisker's CEO and Executive Design Director Henrik Fisker said. "We are very pleased to have signed this agreement with BMW."The firm did not disclose the terms.The U.S. automaker, founded in 2007, has produced electric vehicles with extended range (EVer). The first derivative of "Project Nina" will be a mid-sized premium sedan which utilizes the technology.The company's other products include Fisker Karma Sedan, a luxury sports car and the world's first premium electric plug-in hybrid.

BERLIN, July 26 (Xinhua) -- German national disease control center said on Tuesday that the country's deadly E. coli outbreak has been over, as no new case reported in the last three weeks.The Robert Koch Institute (RKI) said the last case related to the E.coli outbreak was reported on July 4.As a three-week-period would cover the disease's incubation time, diagnosis time and the time for the transfer of a case, this virtually means an end of the outbreak."The largest EHEC outbreak is over in Germany," said RKI President Reinhard Burger. "I pay tribute to people who have joined in the great work, making investigation and looking after the patients."The RKI said Germany would keep watching the deadly EHEC O104: H4 intensively and asked people to pay attention to personal and food hygiene, as individual infection still cannot be ruled out.This round of outbreak has claimed 52 lives and affected more than 4,000 people since early May.The source of this disease was first believed to be cucumbers and tomatoes from Spain, and then was locked onto bean sprouts grown in a farm near Hamburg in the state Lower Saxony. Later European authorities said one batch of fenugreek seeds from Egypt was probably the source.

People look at a W154 Mercedes Benz racing car at a vintage car show marking the German car maker's 125 anniversary at the former Tempelhof airport in Berlin, August 27, 2011.

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