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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, Aug. 3 (Xinhuanet) -- NASA Tuesday confirmed a 4-foot in diameter sphere debris as a fuel tank that was part of the space shuttle Columbia's electrical power system,according to U.S. news reports.NASA engineers identified the 4-foot piece of spherical debris as one of the18 tanks that held chilled oxygen and hydrogen used by the shuttle's electricity-generating fuel cells.This Aug. 1, 2011 handout photo provided by the Nacogdoches Police Department shows a 4-feet in diameter sphere found in Lake Nacogdoches, Texas on Monday, Aug. 1. Police say low water levels at the lake during the drought have led to recovery of a container-like object that could be from space shuttle Columbia. The shuttle broke apart and burned in February 2003, scattering remnants over East TexasPolice in the city of Nacogdoches, about 160 miles northeast of Houston, said Monday the low water levels of Lake Nacogdoches during the record drought revealed an unexpected object that could be from space shuttle Columbia. The shuttle broke apart and burned as it re-entered the atmosphere on February 1, 2003.The tank will be moved to the Kennedy Space Center, where the rest of the Columbia is stored. Approximately 40 percent of the spacecraft has been recovered.

LOS ANGELES, July 19 (Xinhua) -- Obesity prevalence was 30 percent or higher in 12 states of the United States last year, compared to nine states in 2009, the Centers for Disease Control and Prevention (CDC) said on Tuesday.In 2000, no states in the country had obesity rates that high, and now obesity is a problem in all 50 states, the agency said in a report based on telephone interviews with 400,000 people.Obesity rates vary by region, led by the South at 29.4 percent, followed by the Midwest at 28.7 percent, the Northeast at 24.9 percent, and the West at 24.1 percent, the report said.Mississippi had the nation's highest obesity prevalence at 34 percent, and Colorado the lowest at 21 percent, according to the report.Alabama, Arkansas, Kentucky, Louisiana, Michigan, Mississippi, Missouri, Oklahoma, South Carolina, Tennessee, Texas, and West Virginia all had obesity rates of 30 percent or higher in 2010, said the report.No state met the federal Healthy People 2010 goal of a 15 percent obesity rate. In fact, no state had a rate lower than 20 percent, the CDC said.Obesity rates have kept rising despite a steady drumbeat of warnings that obesity causes serious health problems and increases the risk of premature death, CDC officials said.An adult is considered obese if he or she has a body mass index (BMI) of 30 or greater.

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.

SAN FRANCISCO, July 6 (Xinhua) -- Facebook on Wednesday introduced a new video calling feature powered by Skype and some improvements to the chat designs on the social networking site.According to Facebook, users can reach video calling from a new "Call" button on a friend's profile or from the chat panel after downloading a Skype application. A recipient will receive an alert that they are being called and can then accept or decline.At the press event held at Facebook headquarters in Palo Alto, California, CEO Mark Zuckerberg said the feature will begin with one-on-one video chat. Skype CEO Tony Bates, whose company has been acquired by Microsoft, said Skype is considering having its paid product within the Facebook product.The social networking company also introduced "Ad Hoc Group Chat", which enables users to start a group chat instantly without creating a group with those multiple friends at first. The new group chat feature is also available for Facebook's mobile interfaces.Facebook also introduces a sidebar that lists the people a user messages most, enabling users to chat with close friends, professional contacts or co-workers without being interrupted. The sidebar can adjust with the size of users' browser window and automatically appears when the window is wide enough.In the opening remarks at the press event, Zuckerberg confirmed that Facebook had surpassed 750 million monthly active users. He said the company had declined to announce the number earlier because it has become focused on other metrics, like how actively users are sharing information.The CEO said users are now sharing 4 billion "things" on Facebook every day, which grew at an exponential rate compared to the amount users share a year ago."Social networking is at an inflection point," said Zuckerberg, adding that he believes social networking now is more about the strength of connecting people rather than the quantity of users or ubiquity of the technology.Zuckerberg presented a graph to show how Facebook product launches have helped drive the growth of sharing. He said the social network expects more innovations from other companies involved in everything from music to communication to help drive the growth.

来源：资阳报