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CANBERRA, Aug. 17 (Xinhua) -- Australian scientist on Wednesday said his international research team has discovered the trick on how butterfly learn to change its wing pattern to avoid being eaten by birds.The Amazonian butterfly, Heliconius numata, has learnt to carry out a single genetic switch to alter its wing pattern so it appears to be another bad-tasting butterfly that birds will avoid.Dr. Siu Fai (Ronald) Lee from the Department of Genetics and Bio21 Institute at Australia's University of Melbourne was part of the international research team, which was led by scientists at Centre National de la Recherche Scientifique (CNRS) and the University of Exeter in United Kingdom.Dr. Lee said the historical mystery had puzzled researchers for decades."Charles Darwin was puzzled by how butterflies evolved such similar patterns of warning coloration," Dr. Siu Fai (Ronald) Lee from the Department of Genetics and Bio21 Institute at the University of Melbourne told Western Australia Today."We have now solved this mystery, identifying the region of chromosome responsible for changing wing pattern."He said the research team identified a genetic switch known as a supergene, which allowed the butterfly to morph into several different forms, allowing one species to mimic another."It is amazing that by changing just one small region of the chromosomes, the butterfly is able to fool its predators by mimicking a range of different butterflies that taste bad," he said."The butterflies rearrange this supergene DNA like a small pack of cards, and the result is new wing patterns. It means that butterflies look completely different but have the same DNA."There are other butterflies doing similar tricks, but this is the most elegant one."I was just fascinated by how elegant they were."He said the discovery proves that small chromosomal changes can preserve successful gene combinations, and thus help a species to adapt.The findings of the study are published on August 14 in the international journal Nature.

BEIJING, Aug. 1 (Xinhua) -- The provinces of Guizhou and Hunan reported their lowest levels of precipitation since 1951 in July, the China Meteorological Administration (CMA) said on Monday.Precipitation levels across the country saw a decrease of 8.7 percent from the average level of 115.9 mm in July, the lowest levels seen in 11 years, said Chen Zhenlin, an expert with the CMA.The average temperature recorded across the country in July was 22.1 degrees Celsius, up 0.7 degrees Celsius from the average level.

SAN FRANCISCO, June 15 (Xinhua) -- Facebook has hired Joe Lockhart, who was former U.S. President Bill Clinton's press secretary during the last two years of his second term, as the social network company's vice president of global communications, U.S. media reported on Wednesday.Lockhart, 51, will report to Elliot Schrage, Facebook's current vice president of global communications, marketing and public policy, The Wall Street Journal said in a report."His experience building and running a press office at the White House gives him particular appreciation for the demands of a global 24-hour news cycle and the challenges of responding effectively to intense scrutiny," Schrage said of Lockhart's arrival.Lockhart will start at Facebook on July 15 and will move from Washington D.C. to Facebook's headquarters in California.Lockhart is the latest Washington insider to join Facebook as the world's largest social networking site is facing intense scrutiny for its privacy practices and growing global presence, The Wall Street Journal pointed out.Last year, Facebook also hired White House economic adviser Marne Levine to serve as its vice president of global public policy.More recently, Facebook hired former Bush administration officials Joel Kaplan as its vice president for U.S. public policy, and Myriah Jordan, who will become a policy manager focusing on congressional relations.

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.

RIO DE JANEIRO, July 28 (Xinhua) -- Brazilians are eating a lot of rice and beans as well as high-calorie junk food lacking nutrition, a study released Thursday by the Brazilian Institute of Geography and Statistics (IBGE) found.According to the study, over 90 percent of Brazilians eat daily helpings of fruits and vegetables lower than the levels recommended by the Health Ministry (400 grams). Also,the consumption of sugary drinks (juices, fruit drinks and soft drinks) is twice as high as recommended by the ministry.Rice and beans, along with coffee and juices, are the most popular in Brazilians' diet. Teenagers are the main consumers of those drinks, drinking twice as much as adults. Men eat less greens and fruits than women, but drink five times more alcohol.In urban areas, the consumption of beer, soft drinks, sandwiches, and salty bread is higher. Brazilians in rural areas have a healthier diet, richer in rice, beans, fish, cassava flour, and sweet potatoes.Along with a lack of physical activity, the Brazilians' poor diet was cited as one of the main causes of obesity in the country. According to a Health Ministry study published in April, 48 percent of Brazilians are overweight, and 15 percent are obese.

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