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BEIJING, June 29 (Xinhuanet) -- Twitter Inc. co-founders Biz Stone and Evan Williams said they are moving on from the microblogging service, media reports said Wednesday.“The Twitter crew and its leadership team have grown incredibly productive,” Stone said on the blog. “I’ve decided that the most effective use of my time is to get out of the way until I’m called upon to be of some specific use.”The two will continue to advise Twitter on strategic matters, but devote the lions' share of their time to The Obvious Corporation, Stone said.Obvious was first created by Williams to buy back a company from investors that he and Stone failed to sell about six years ago, Stone said. The two began working together after leaving Google in 2005.The company will also be run by Jason Goldman, a former Twitter executive, Stone said.

MOSCOW, Sept. 16 (Xinhua) -- A Russian Soyuz space capsule carrying three astronauts returned to the Earth Friday, the Mission Control Center outside Moscow confirmed.The three astronauts, two Russians and one American from the International Space Station (ISS), who were flown back by a Soyuz TMA-21 spacecraft, were in good condition, search and rescue teams on the ground in Kazakhstan said.Russian TV images showed the three ISS crew members being taken out of the space capsule and seated in armchairs with blankets to re-adapt to the Earth's gravity.According to the Cosmonaut Training Center, the astronauts underwent physical examinations immediately after the landing, which included examinations of hearts, lungs and adrenal glands.Seventeen helicopters and planes had waited for the capsule's landing.Helicopters will carry the astronauts from the landing site to the Kazakh city of Karaganda, from where the two Russian cosmonauts Alexander Samokutyayev and Andrei Borisenko will fly back to Moscow later Friday, while NASA astronaut Ronald Garan will leave directly for the United States for post-mission rehabilitation, the Itar-Tass news agency reported.The return of the three crew members was originally scheduled for Sept. 8, but was postponed by a failed launch of the Progress cargo ship on Aug. 24.The three crew members remaining on board the ISS are scheduled to return in mid-November.

BEIJING, Aug. 22 (Xinhuanet) -- Researchers have discovered how a human egg captures an incoming sperm for fertilization, paving the way to help couples suffering from infertility, according to media reports on Monday.An international team of researchers found that a sugar chain known as the sialyl-lewis-x sequence (SLeX) makes the outer coat of the egg “sticky,” which has proven to be helpful in binding the egg and the sperm.As a result, this observation has filled in a huge gap in the understanding of fertility and provides hope for ultimately helping couples who currently cannot conceive.Scientists and doctors know that a sperm identifies an egg when proteins on the head of the sperm match and bind to a series of specific sugars in the egg’s outer coating. With a successful match of proteins, the outside surfaces of the sperm and egg then bind together before merging, which is then followed by delivery of sperm’s DNA into egg.To identify this molecules, the researchers used ultra-sensitive mass-spectrometric imaging technology to observe and identify which molecules are most likely to be key in the binding process.They experimented with a range of synthesised sugars in the laboratory and found that it is SLeX that specifically binds sperm to an egg.According to the World Health Organisation, infertility affects about 15 percent of reproductive-aged couples around the world and almost one in every seven couples in Britain has problems conceiving a child for various reasons.

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."

WASHINGTON, July 18 (Xinhua) -- The U.S. National Aeronautics and Space Administration (NASA) on Monday commemorated the 90th birthday of astronaut John Glenn, the first U.S. astronaut to orbit the Earth and also the oldest person to fly to space when he launched on the space shuttle in 1998."John Glenn is a legend, and NASA sends him our best wishes on this major personal milestone," NASA Administrator Charles Bolden said in a statement. "John's legacy and contributions to the continued progress of human spaceflight are immense. His example is one we continue to emulate as we push toward farther destinations in the solar system."After a distinguished flying career with the Marines in World War II and Korea, Glenn joined NASA in 1959 as one of the country' s first astronauts in Project Mercury. On Feb. 20, 1962, Glenn piloted the Mercury-Atlas 6 "Friendship 7" spacecraft on the first U.S. manned orbital mission. He launched from NASA's Kennedy Space Center in Florida to successfully complete three orbits of the Earth.Glenn flew to space again on the STS-95 mission in 1998 aboard the space shuttle Discovery. As a mission specialist, Glenn supported deployment of a variety of research payloads and participated in investigations about spaceflight and the aging process.

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