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CANBERRA, Sept. 23 (Xinhua) -- A genetic study on Friday found Aboriginal Australians are descended from the first people to leave Africa up to 75,000 years ago.Researchers from the University of Western Australia, Murdoch University and an international team analyzed genetic material of a 100-year-old West Australian Aboriginal man's hair, and found he was directly descended from a migration out of Africa into Asia.The study revealed that Australian Aboriginal ancestors split from the first modern human populations to leave Africa, between 64,000 and 75,000 years ago, at least 24,000 years before other human migrations.According to Dr. Joe Dortch, an archaeologist at the University of Western Australia, the discovery rewrites the history of the human species by confirming humans moved out of Africa in waves of migrations rather than in one single out-of-Africa diaspora.It also rewrites the story about how Aborigines arrived in Australia some 50,000 years ago."So far there are no [archaeological] sites that are over 50, 000 years old so it puts a time limit on that and focuses our future efforts," he said in a statement released on Friday.Dr. Dortch believes the finding will foster a sense of pride in modern Australian Aborigines."No-one else in the world can say 'I am descended from people who have been here 75,000 years'."Associate Professor Darren Curnoe, leader of the Human Evolutionary Biology Lab in the School of Biological, Earth & Environmental Sciences at the University of New South Wales, said the study powerfully confirms that Aboriginal Australians are one of the oldest living populations in the world, certainly the oldest outside of Africa."Australians are truly one of the world's great human populations and a very ancient one at that, with deep connections to the Australian continent and broader Asian region. About this now there can be no dispute," he told Xinhua in an email note.Meanwhile, Professor Alan Cooper, Director of the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, said while this is a major step forward, the key unresolved question remains the unique story of Aboriginal history within Australia, such as what has happened in those 50,000 years of life in the harsh Australian environment."Unfortunately, the information from a single individual tells us very little about this fascinating, and critically important part of human history. Aborigines are one of the oldest continuous human populations outside Africa, as they note in the paper, and due to the geographic isolation and limited archaeological records remain one of the most mysterious chapters in human history," he told Xinhua on Friday.The study is published on Friday in the journal Science.Indigenous Australians are the original inhabitants of the Australian continent and nearby islands. They together make up more than 2.5 percent of Australia's population.

BEIJING, June 28 (Xinhuanet) -- The figure of adults with diabetes has risen to 347 million worldwide, which is more than doubled in the past three decades, according to a study published in the British journal Lancet.The study, which analyzed data compiled from 2.7 million participants aged 25 and over from across the world, shows approximately 138 million in China have diabetes, and 36 million in the United States.Among high-income countries, diabetes rates were the highest in the U.S., Greenland, Malta, New Zealand, and Spain. The Netherlands, Austria, and France boasted the lowest rates, suggested the study published online by The Lancet journal on June 25.Majid Ezzati, a lead author of the study, said on Reuters: “Diabetes is becoming more common almost everywhere in the world.”Danaei added: “Unless we develop better programs for detecting people with elevated blood sugar and helping them to improve their diet and physical activity and control their weight, diabetes will inevitably continue to impose a major burden on health systems around the world.”

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.

BEIJING, Sept. 6 (Xinhuanet) -- The amount of space junks floating in Earth's orbit has reached a critical level, warned scientists.The future space missions may become too dangerous to fly for a risk of colliding with space junks, said a report released recently by the U.S. National Research Council (NRC).The kinds of space junks range from huge, the report said, there are thousands of discarded satellites and rocket boosters and countless tiny pieces of daily gabages from space missions.The debris are traveling in orbit at 17,500mph, at such a speed even a tiny clash can destroy a spacecraft.The NRC recommended that NASA should launch a plan to clean up the floating debris and called on other major space nations' cooperation."The current space environment is growing increasingly hazardous to spacecraft and astronauts," said Kessler, an ex-NASA researcher, "NASA needs to determine the best path forward for tackling the multifaceted problems caused by meteoroids and orbital debris that put human and robotic space operations at risk."

SAN FRANCISCO, June 28 (Xinhua) -- Google on Tuesday rolled out a new social networking service named "Google+", a long awaited move of the Internet search giant to crack the industry's social trend dominated by Facebook.Unlike Facebook, Google said that the project is designed for sharing with small groups like college roommates and parents. " Today's online services turn friendship into fast food, wrapping everyone in 'friend' paper," Google said in a blog post announcing the new service.Other Google+ features include Sparks, which gathers articles and videos on topics of interests or hobbies; and Hangouts, which allows users join live multi-person video chat.There is also a mobile version of Google+ for smartphones running Google's Android operating system, which enables multi- person text message chats and instant upload of photos from the phone.The Google+ project is currently in field trial and by invitation only. Users can select people from their Gmail contacts and organize them into different groups.Google+ is expected to test whether Google could come back from its past frustration in social networking, such as Buzz, a social networking and messaging too integrated into its Gmail service. Some of Google Buzz's features have been widely criticized for privacy concerns.Market research data show that Facebook has surpassed Google in terms of time spent on each site, a fact that advertisers attach importance to.According to Internet market research company comScore, including YouTube, 180 million people visited Google sites in May, compare to 157.2 million on Facebook. However, Facebook users looked at 103 billion pages and spent an average of 375 minutes on the site, while Google users viewed 46.3 billion pages and spent 231 minutes.In April, Google CEO and co-founder Larry Page reportedly sent out a company-wide memo alerting employees that 25 percent of their annual bonus will be tied to the success or failure of Google's social strategy in 2011.

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