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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.

VIENNA, Aug. 11 (Xinhua) -- Austrian researchers have developed a method of using fungi and produced enzymes to split Polyethylene Terephthalate (PET) material into their initial state, enabling the recovery of all individual components, said the Austrian Center of Industrial Biotechnology (ACIB) Thursday in a press release.Enzyme is a special protein that acts as biological catalyst, for example, bacteria and fungi in the nature can break down long chain molecules.Researchers from the Technical University of Graz, the Technical University of Vienna and the Agricultural University of Vienna jointly found that efficient enzymes are capable to break and split PET into small fragments.With different methods, the researchers forced the fungi to overproduce their precious "split-tools" after they are modified and improved by genetic engineering.Through the new method developed by the ACIB, it is now possible to decompose the PET polymer to its initial monomers with high product quality and from this to produce new high-quality materials again.This circuit avoids waste and thus saves resources and is friendly to the environment, said Geog Guebitz, head of the Research Department on Enzymes and Polymers in the ACIB.He further explained that the ACIB has established a partnership with some industrial enterprises to carry out application experiments. From the current splitting time of 24 hours, the researchers expect to shorten the whole process to "a few hours," he added.PET is a common plastic material in the polyester family, widely used in the textile industry. PET film is mainly used in electrical insulation materials, which can be also used for production of film, X-ray films and computer taps, even to produce plastic bottle and other blow molding products.

LOS ANGELES, May 30 (Xinhua) -- The American Academy of Pediatrics (AAP) warned on Monday that children should keep away from energy drinks which may be dangerous for minors.The AAP urged young children and teens to avoid energy drinks entirely, saying routine consumption of sports drinks should be limited or eliminated.Energy drinks include such popular brands as Red Bull, AMP and Rockstar, the AAP said in a report.These drinks, the report said, tend to be heavily caffeinated, potentially having several times the level of caffeine found in a cup of coffee.In addition, manufacturers often add sugar and herbal stimulants such as guarana and taurine to the drinks, which are popular among kids, according to the report."There's no place for energy drinks for kids," said report co-author Dr. Marcie Beth Schneider, an adolescent physician in Greenwich, Connecticut. "There's a place for sports drinks, but that place is very specific."The caffeine in energy drinks can lead to high blood pressure, high heart rate and insomnia, she said.The other ingredients can boost the power of the caffeine, she said, adding that the drinks will have a greater effect on children because they're smaller than adults."Kids don't need to have this," she said. "This is not something they should be drinking."Schneider declined to identify any energy drinks that may be better than others for kids who insist on drinking them. If kids use energy drinks because they're tired, she said, they should get more rest instead of chugging caffeine.Half of the nation's 5,448 reported caffeine overdoses in 2007 were in people under age 19, although it's not known how many of the cases were the result of energy drink consumption, according to statistics provided by the AAP.

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.

BEIJING, Aug. 24 (Xinhua) -- China will prioritize the development of six types of new materials in its new material industry over the next five years, the China Securities Journal said on Wednesday.The report cited an insider, who noted that the country's 12th Five-Year Plan (2011-2015) for the new material industry will come out in September, in which the government will launch key projects to support the development of the six materials.The six materials will be high-strength light alloy, advanced iron and steel, carbon fiber composite, new power battery material, function coated material, and rare earth function material, according to the report.The plan states each of the six sub industries will form a sizable industrial scale, with the industry's total output value to hit trillions of yuan by the end of 2015, and the self-supply rate to reach 70 percent during the period, the report said.Meanwhile, the government will also foster the development of materials in sectors such as green building material and the biomedical industry over the next five years, it added.

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