中山屁股会出血(中山大便硬带血怎么回事) (今日更新中)

PHNOM PENH, Aug. 17 (Xinhua) -- The critically endangered Irrawaddy dolphin population in the Mekong River numbers just 85, World Wildlife Fund (WWF) new research revealed on Wednesday.Calf survival was found to be very low, leading researchers to conclude that the small population is declining and at high risk of extinction, said the Fund's statement sent to Xinhua News Agency on Wednesday.According to Li Lifeng, Director of WWF's Freshwater Program, the research is based on photographic identification of dolphins through individually unique features of their dorsal fins. "Most of the dolphins can be identified, and we use that information to estimate the population size," he said.Although this population estimate is slightly higher than the previous estimate, the researchers were quick to note that the population had not increased over the last few years."With a larger dataset and recent analytical advances, previously unidentifiable dolphins which had few marks on their dorsal fins have been included," he added.However, surveys conducted from 2007 to 2010 show the population slowly declining."Evidence is strong that very few young animals survive to adulthood, as older dolphins die off and are not replaced," he explained."Pressures of gill net entanglement and high calf mortality we are really worried for the future of dolphins," Li said.However, Touch Seang Tana, chairman of Cambodia's Commission for Conversation and Development of the Mekong River Dolphins Eco- tourism Zone, rejected the WWF's finding, saying that last year, 4 dolphins were killed by fishing nets, but up to 7 newborn dolphin babies were found.He estimated that the total population of Mekong dolphins in the north-eastern provinces of Kratie and Stung Treng is between 155 and 177 now, up from just 100 in 2006.The Mekong River Irrawaddy dolphin has been listed as critically endangered on the World Conservation Union Red List of Threatened Species since 2004.

BEIJING, Sept. 26 (Xinhuanet) -- One of the world's brightest minds aims to bring to the world a new, advanced three-dimensional image technology that will leave other such technology in the shadows."Our new technology will be better than that used in Avatar," says Professor Yau Shing-tung of Harvard University."The image will be more vivid than with technologies used in previous movies. The new technology is not only quicker but cheaper."Yau is one of the world's greatest mathematicians, having won the prestigious Fields Medal. He was once the dean of the department of mathematics at Harvard, and is now a professor there. He is also a visiting professor at Tsinghua University.Professor Yau and his team met professionals from Tsinghua University and Renmin University of China last week, and they discussed possible cooperation to apply the technology in making a demonstration movie using the new technology.Yau and a team started working on the new 3D technology, founded on geometrical principles, at Harvard 10 years ago.What marks it out is the extremely vivid pictures it produces.3D technology is used not only in making movies and in Internet games but in other areas , such as medicine. Movie audiences the world over were awestruck by the technology used in the movie Avatar."After I watched the movie, all I could say was 'Wow'," said Shen Yiren, an IT staff worker in Zhongguancun Science and Technology Park Zone. "3D technology has extended the boundaries of the human imagination."Yau says that six years ago the makers of Avatar had wanted him to cooperate with them but he turned them down."I was not sure that (Avatar) would be such a big success."Avatar's facial caption technology puts points on models' faces while the new technology uses geometric methods, saving time and money, Yau says.

BEIJING, Sept. 25 (Xinhua) -- As China's economy has soared to the second place in the world, the country's scientific strength has also surged -- if only measured by the numbers.Chinese researchers published more than 1.2 million papers from 2006 to 2010 -- second only to the United States but well ahead of Britain, Germany and Japan, according to data recently published by Elsevier, a leading international scientific publisher and data provider. This figure represents a 14 percent increase over the period from 2005 to 2009.The number of published academic papers in science and technology is often seen as a gauge of national scientific prowess.But these impressive numbers mask an uncomfortable fact: most of these papers are of low quality or have little impact. Citation per article (CPA) measures the quality and impact of papers. China's CPA is 1.47, the lowest figure among the top 20 publishing countries, according to Elsevier's Scopus citation database.China's CPA dropped from 1.72 for the period from 2005 to 2009, and is now below emerging countries such as India and Brazil. Among papers lead-authored by Chinese researchers, most citations were by domestic peers and, in many cases, were self-citations."While quantity is an important indicator because it gives a sense of scientific capacity and the overall level of scientific activity in any particular field, citations are the primary indicator of overall scientific impact," said Daniel Calto, Director of SciVal Solutions at Elsevier North America.Calto attributed China's low CPA to a "dilution effect.""When the rise in the number of publications is so rapid, as it has been in China -- increasing quantity does not necessarily imply an overall increase in quality," said Calto.He noted the same pattern in a variety of rapidly emerging research countries such as India, Brazil, and earlier in places like the Republic of Korea."Chinese researchers are too obsessed with SCI (Science Citation Index), churning out too many articles of low quality," said Mu Rongping, Director-General of the Institute of Policy and Management at the Chinese Academy of Sciences, China's major think tank.SCI is one of the databases used by Chinese researchers to look-up their citation performance. The alternative, Scopus, provides a wider coverage worldwide."Chinese researchers from a wide range of areas and institutions are vying for publication, as it is a key criterion for academic appraisal in China, if not the only one. As a result, the growth of quality pales in comparison to that of quantity," said Mu, an expert on China's national science policy and competitiveness.On the other hand, China also falls behind the United States in multidisciplinary research, which is a core engine for scientific advance and research excellence.From 2006 to 2010, China published 1,229,706 papers while the United States churned out 2,082,733. According to a new metric introduced by Elsevier's Spotlight research assessment solution, China generated 885 competencies while the United States had 1,817.In other words, China's total research output is more than half that of the United States, while the number of competencies showing China's strength in multidisciplinary research is less than half that of the United States.Cong Cao, an expert on China's science and technology, put it more bluntly in an article he wrote: "When the paper bubble bursts, which will happen sooner or later, one may find that the real situation of scientific research in China probably is not that rosy."China has been investing heavily in scientific research and technological development in recent years to strengthen its innovative capacity, The proportion of GDP spent on R&D grew from 0.9 percent in 2000 to 1.4 percent in 2007, according to the World Bank.An IMF forecast in 2010 says China now ranks second globally in R&D spending. The IMF calculates China's R&D expenditure at 150 billion U.S. dollars when based on Purchasing Power Parity, a widely used economic concept that attempts to equalize differences in standard of living among countries.By this measure, China surpassed Japan in R&D spending in 2010.Many see China's huge investment in R&D as the momentum behind the country's explosive increase in research papers."Getting published is, in some ways, an improvement over being unable to get published," Mu said. "But the problem is, if the papers continue to be of low quality for a long time, it will be a waste of resources."In China, academic papers play a central role in the academic appraisal system, which is closely related to degrees and job promotions.While acknowledging the importance of academic papers in research, Mu believes a more balanced appraisal system should be adopted. "This is a problem with science management. If we put too much focus on the quantity of research papers, we leave the job of appraisal to journal editors."In China, the avid pursuit of publishing sometimes gives rise to scientific fraud. In the most high-profile case in recent years, two lecturers from central China's Jinggangshan University were sacked in 2010 after a journal that published their work admitted 70 papers they wrote over two years had been falsified."This is one of the worst cases. These unethical people not only deceived people to further their academic reputations, they also led academic research on the wrong path, which is a waste of resources," Mu said.A study done by researchers at Wuhan University in 2010 says more than 100 million U.S. dollars changes hands in China every year for ghost-written academic papers. The market in buying and selling scientific papers has grown five-fold in the past three years.The study says Chinese academics and students often buy and sell scientific papers to swell publication lists and many of the purported authors never write the papers they sign. Some master's or doctoral students are making a living by churning out papers for others. Others mass-produce scientific papers in order to get monetary rewards from their institutions.A 2009 survey by the China Association for Science and Technology (CAST) of 30,078 people doing science-related work shows that nearly one-third of respondents attributed fraud to the current system that evaluates researchers' academic performance largely on the basis of how many papers they write and publish.Despite rampant fraud, China will continue to inject huge money into science. According to the latest national science guideline, which was issued in 2006 by the State Council, the investment in R&D will account for 2.5 percent of GDP in 2020."If China achieves its stated goal of investing 2.5 percent of its GDP in R&D in 2020, and sustains its very fast economic growth over the next decade, it would quite likely pass the U.S. in terms of total R&D investment sometime in the late 2010s," said Calto, adding that it is also quite likely that at some point China will churn out more papers than the United States.According to Calto, China does mostly applied research, which helps drive manufacturing and economic growth, while basic research only accounts for 6 percent, compared with about 35 percent in Germany, Britain, and the United States, and 16 percent in Japan."In the long term, in order to really achieve dominance in any scientific area, I think it will be necessary to put significant financial resources into fundamental basic research -- these are the theoretical areas that can drive the highest level of innovation," Calto said.

SAN FRANCISCO, Aug. 10 (Xinhua) -- Amazon on Wednesday launched Kindle Cloud Reader, a web-based app that may help the on-line retailer to sidestep Apple's App Store restrictions.In its announcement, Amazon said Kindle Could Reader uses the HTML5 web standard to let users read e-books from their Kindle library from the Safari browser or Google's Chrome browser on their desktops or tablet, including the iPad.Support for Internet Explorer, Firefox and the Blackberry Playbook will be launched later this year.The app has a button linked to the Kindle Store, which was removed recently from the Kindle apps for iPad and iPhone.The move is taken as an answer to Apple's latest App Store restrictions, which banned developers to have any external links for purchasing digital books or subscriptions in the app, unless they give Apple a 30 percent cut from the in-app sales.Besides Amazon, Barnes & Noble, Google Books and Canadian e- book seller Kobo have also altered their iPad and iPhone apps to comply with the rules.Meanwhile, publishers and retailers have been developing web- based HTML5 apps to sidestep Apple for more control, which is an approved-of technology for iOS devices.The Financial Times, Kobo and video-on-demand service Vudu have recently launched their HTML5 app to avoid paying Apple a 30 percent cut.Industry watchers said it is unknown how Apple will deal with such apps. It would be easy for Apple to disable Web apps in the iPad's Safari browser, but the company would certainly face some backlash, said tech media website CNET.

LOS ANGELES, July 28 (Xinhua) -- Mainly due to rampant obesity, Americans' life expectancy is one-and-a-half-year shorter than that of Western Europeans on the average, according to a new study published on Thursday.But 40 years ago, Americans could expect to live slightly longer than Europeans, said the study jointly conducted by researchers from University of Southern California (USC), the Harvard School of Public Health and the RAND Corp., a non-profit think tank.In addition to Western Europeans, Americans also die younger than the residents of most other developed nations, according to the study appearing in the July issue of Social Science & Medicine.The life-expectancy disparity, which begins around the age of 50, stems from higher levels of middle-age obesity and obesity-related chronic diseases, such as hypertension and diabetes, said the study.In the first half of the last century, average life expectancy increased by saving more babies, said author Dana Goldman, director of the Schaeffer Center for Health Policy and Economics at the USC."But now it is reduction in mortality among the elderly, rather than the young, that propels increases in life expectancy," he said. "The question is whether 'being American' is an independent mortality risk factor."If 50-year-old U.S. adults could be as healthy as Europeans, it could save Medicare and Medicaid 632 billion dollars by 2050, the study said.Though the transition to better health initially raises expenditures, the researchers estimate that by 2050 healthcare savings from health improvements among the middle age could total more than 1.1 trillion dollars."The international life expectancy gap appears much easier to explain than gaps within countries: there is no American-specific effect on longevity beyond differences in disease at age 50," said Darius Lakdawalla, an associate professor in the USC School of Policy, Planning and Development.

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