昌吉哪家可以做流产(昌吉包皮手术后费用) (今日更新中)

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.

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.

SAN FRANCISCO, Sept. 27 (Xinhua) -- Apple on Tuesday announced an invitation-only special event featuring iPhone on Oct. 4, 2011.With a simple headline reading "Let's talk iPhone," the invitation said that there will be an "executive presentation at 10 a.m.." This could be the first big product introduction by the newly installed Chief Executive Officer Tim Cook after he took over the reins of Apple from Steve Jobs in August.The event, which will be held at Apple campus in Cupertino, California, has long been reported to be the introduction of iPhone 5, the next generation iPhone.According to U.S. media reports, the iPhone 5 is expected to have revamped hardware design with a larger screen, a higher resolution camera and a faster dual-core A5 chip on which the iPad 2 runs. Apple is also reported to release a low-cost and contract- free iPhone model bundled with its cloud computing service iCloud.

SYDNEY, July 1 (Xinhua) -- Breastfeeding mothers should limit their use of codeine-containing painkillers to four days as they can cause harm, an Australian doctor warned on Friday.The warning is being discussed at a meeting of anesthetists in Sydney."New mothers should limit their use of codeine-containing painkillers to no more than four days and, if they feel drowsy while taking this medication, cease its use and have their baby examined by a doctor for signs of drowsiness," Sydney's Royal North Shore Hospital anesthetist Dr. Gavin Pattullo said."This is because codeine needs to be metabolized by the liver into morphine to offer pain relief and this liver conversion process is very unpredictable," Pattullo said."Some patients' livers produce large amounts of morphine after taking codeine, causing drowsiness, while others fail to produce any morphine at all."Pattullo said for breastfeeding mothers, a large dose of morphine could make its way into the baby and result in the baby's death by overdose."While new mums shouldn't be unnecessarily alarmed, they need to be aware that codeine-containing painkillers in certain circumstances can cause harm," he said.Breastfeeding mothers are being advised to see a doctor if their baby gets sleepy while taking the painkillers.

来源：资阳报