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WASHINGTON, June 15 (Xinhua) -- Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe, the U.S. National Aeronautics and Space Administration (NASA) said Wednesday in a statement.The discovery from NASA's Chandra X-ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies.By pointing Chandra at a patch of sky for more than six weeks, astronomers obtained what is known as the Chandra Deep Field South (CDFS). When combined with very deep optical and infrared images from NASA's Hubble Space Telescope, the new Chandra data allowed astronomers to search for black holes in 200 distant galaxies, from when the universe was between about 800 million to 950 million years old."Until now, we had no idea what the black holes in these early galaxies were doing, or if they even existed," said Ezequiel Treister of the University of Hawaii, lead author of the study to appear Thursday in journal Nature. "Now we know they are there, and they are growing like gangbusters."The super-sized growth means that the black holes in the CDFS are less extreme versions of quasars -- very luminous, rare objects powered by material falling onto supermassive black holes. However, the sources in the CDFS are about a hundred times fainter and the black holes are about a thousand times less massive than the ones in quasars.The observations found that between 30 and 100 percent of the distant galaxies contain growing supermassive black holes. Extrapolating these results from the small observed field to the full sky, there are at least 30 million supermassive black holes in the early universe. This is a factor of 10,000 larger than the estimated number of quasars in the early universe."It appears we've found a whole new population of baby black holes," said co-author Kevin Schawinski of Yale University. "We think these babies will grow by a factor of about a hundred or a thousand, eventually becoming like the giant black holes we see today almost 13 billion years later."

BEIJING, August 4 (Xinhuanet) -- Medtronic Inc. is giving Yale University a 2.5 million U.S. dollar grant to review the safety and effectiveness of its controversial spine treatment called Infuse Bone Graft, according to The Wall Street Journals Thursday.Under terms of the pact, the company will release to Yale and eventually the public what participants described as an unprecedented amount of clinical trial and other data. The university will select two research teams from other organizations to perform separate analyses of the data.The announcement comes in the wake of a paper in June in the Spine Journal. The paper revealed that several clinical studies of Infuse, conducted by surgeons with strong economic ties to Medtronic, failed to report serious complications that arose in the trials. The critical paper also found that many of the studies were designed in ways in favor of Infuse over a treatment given to a control group.Medtronic disputes some of the findings and is conducting an internal investigation of the matter.Infuse accounts for about 700 million dollars in annual sales for Medtronic. The product is under investigation by the Senate Finance Committee over the role payments to physicians who may have played how studies were reported.

SAN FRANCISCO, Sept. 12 (Xinhua) -- Amazon.com Inc. is talking with book publishers to launch a rental subscription service for digital books, U.S. media reported on Monday.Several publishing executives said they aren't enthusiastic about the idea because it could lower the value of books and it could also strain their relationships with other retailers that sell their books, The Wall Street Journal quotes people familiar with the matter in a report.The Seattle-based company is considering a digital book library featuring old titles, which would be available to Amazon Prime subscribers, who currently pay 79 U.S. dollars a year for access to digital library of movies and TV shows and unlimited two-day shipping, said the report.Amazon would offer book publishers a substantial fee and could limit the amount of books that Amazon Prime customers could read for free every month, the report cited some sources as saying.The online retailing giant makes the popular electronic reader Kindle and is also reported to launch a color touchscreen tablet before October to compete with Apple's iPad and other devices in the increasingly crowded tablet computer market.The proposal is another sign that retailers are looking for more ways to deliver content digitally as customers increasingly read book and watch TV on personal computers, tablets and other electronic devices, said The Wall Street Journal report.

CANBERRA, Sept. 6 (Xinhua) -- A rare virus that can be contracted by humans has killed a large number of Victorian pigeons after being detected in the Australian state for the first time, Agriculture Department confirmed on Tuesday.According to the Australian Chief Veterinary Officer, Dr Mark Schipp, the avian paramyxo virus has already started killing some hobby birds, and threatens to spread to Victoria's chicken population.He said the affected birds have died suddenly in large numbers and have sometimes appeared tired or have shown neurological signs such as circling or head flicking before death.He added that the bug can also cause conjunctivitis or influenza-like symptoms in humans."The virus causes only mild, short-term conjunctivitis or influenza-like symptoms (in humans)," Australia Associated Press quoted Schipp as reporting on Tuesday."Human infection with this virus is extremely rare and usually occurs only in people who have close direct contact with infected birds."At this stage, there are no reports of the virus causing disease in wild birds, but the Australian Wildlife Health Network has been asked to monitor the situation.

LOS ANGELES, June 7 (Xinhua) -- Salmonella, not E. coli, poses the greatest health threat to Americans, the U.S. Centers for Disease Control and Prevention (CDC) announced on Tuesday.Salmonella infections have risen 10 percent over the past 15 years, while several types of foodborne illness have been falling, the agency said in a report.Infections from Shiga toxin-producing E. coli O157 (the strain of most concern in the United States) have dropped almost in half and the rates of six other foodborne infections have been cut 23 percent, the CDC said.The agency issued the report as a deadly new strain of E.coli is spreading in several European countries."There are about 50 million people each year who become sick from food in the U.S.. That's about one in six Americans," CDC director Dr. Thomas R. Frieden said.The CDC attributed the reduction in infections from E. coli O157 to better detection and investigation of outbreaks, cleaner slaughterhouse methods, better testing of ground beef for E. coli, improved inspections of ground beef processing plants, regulations prohibiting E. coli O157 in ground beef and increased awareness of the importance of properly cooking beef.Other foodborne illnesses that fell in incidence over the same time period include those caused by the campylobacter, listeria, vibrio and yersinia pathogens.To reduce their risk of foodborne illness, people should assume that raw chicken and other meat have bacteria that can make you sick, the CDC said.In the kitchen, raw meats should not allow to contaminate counter tops or cutting boards and should be kept away from other foods, such as fruits and vegetables, the CDC advised.The agency also called on people to thoroughly cook meat, poultry, eggs and shellfish, while refraining from consuming unpasteurized milk, juice or soft cheese.

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