中山经常便血存在什么危险(中山痔疮安氏疗法疗效) (今日更新中)

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, June 15 (Xinhua) -- As social networking sites like Facebook and Twitter grow worldwide, more Internet retailers are beefing up their efforts to add social twists to their business, trying to define the idea of "social commerce" and capitalize the opportunity.On Wednesday, online auction giant eBay revealed some of the social features it is planning to launch later this year, while Copious, a San Francisco-based startup, launched its online social commerce marketplace with a slogan of "buying from and selling to people, not strangers."Copious asks users to log in through their Facebook accounts and allows buyers and sellers to see if they have friends in common in their social networking sites. Buyers can see more information about a seller and also see whether anyone in their networks has purchased, shared or commented on an item from a specific seller, rather than anonymity or simple profiles on sites like eBay and Craigslist.As for sellers, Copious has a social pricing mechanism that enables a seller to offer buyers discounts for sharing listings on Facebook and for following the seller on Copious.Jonathan Ehrlich, Copious co-founder and former Facebook head of marketing, told technology blog TechCrunch that the site is centralized around using social data as a signal to help users understand and trust other parties.According to Copious, the startup founded in January 2011 has raised two million U.S. dollars in funding from Foundation Capital, Google Ventures, Blackberry Partners Fund and a number of Silicon Valley angel investors.Also on Wednesday, Christopher Payne, vice president and head of eBay North America, delivered a keynote speech at the Internet Retailer Conference and Exhibition 2011 in San Diego, revealing some features eBay is launching during the social trend.One feature will enable users to log in their Facebook account on eBay's homepage to get product recommendations based on one's purchasing history and things they have "liked" on their Facebook page. Another feature will allow users to post multiple products on their Facebook page to get their friends' opinions and ask them to vote for the final purchase.EBay has been stepping up its social efforts, and Payne said on Wednesday that social is a top-level initiative for Internet retailers. Last month, eBay hired former Yahoo executive Don Bradford to lead its social commerce efforts. Last November, it launched Group Gifts service, enabling users to chip in to buy a gift for someone.A research by Adgregate Market in March showed that more brand websites are losing traffic to their Facebook pages. The study revealed that the "Facebook stores" of most Internet retailers are more efficient at acquiring visitors, indicating social commerce is poised to take off.Although the idea of social commerce is still new, more companies are trying to seize the opportunity in their own moves.There are many other companies taking the social commerce model. Oodle, the exclusive provider of classified ads on the Facebook Marketplace, rolled out a series of social features last December to make more money from social classifieds.In February, Payvment Inc. launched a Facebook Mall, where consumers can shop for more than 1.2 million products among 60,000 retailers in a single shopping cart.Yardsellr, which is often called "an eBay for Facebook," allows sellers to list items at fixed prices in different categories called "blocks," such as jewelry and purses. Prospective buyers can "like" the "blocks" they are interested in on the Yardsellr website or its Facebook page, and then they will get Facebook news feed if a seller has something to offer in the category.Yardsellr said 1.5 million people were following its "blocks" by late December 2010 and the number of new followers is growing by 20,000 daily.

XI'AN, Sept. 18 (Xinhua) -- At least 12 people were killed and 22 others missing over the weekend in rain-triggered landslides in northwestern Shaanxi Province, local officials said.As of 5:30 p.m. Sunday, rescuers had retrieved 10 bodies from beneath the rocks and mud in Baqiao District of the provincial capital of Xi'an, while another five were injured, said Zhu Zhisheng, vice mayor of Xi'an, who was at the site.Another 22 people remained missing, Zhu said, adding the injured were hospitalized and in stable condition.The landslide around 2 p.m. Saturday unleashed about 100,000 cubic meters of rock and mud down the mountain, engulfing a brick factory and destroying part of a nearby ceramics factory in the suburban district of Xi'an.Rescuers found four bodies on Saturday night and six others were retrieved on Sunday.More than 700 police, firefighters and local residents joined the rescue which went on Sunday night.However, the rescue was hampered by three ensuing slides between 10 a.m. and 11 a.m. Sunday as heavy rains continued slashing the city.About 10,000 cubic meters of newly-triggered rock and mud roared down to the site, forcing rescuers to suspend searching temporarily.Heavy downpours in the province also caused havoc in other areas.A heavy rainfall on Saturday night triggered a landslide that buried a residential house in the suburban district of Jintai in Baoji City, some 175 km to the west of Xi'an.Two people were dug out but later died after they were rushed to a nearby hospital, the municipal government of Baoji said in a statement Sunday.The downpours also brought a landslide in the same district early Sunday morning. Three people were saved and sent to a local hospital, according to the statement.The three wounded were in stable condition, doctors at the hospital said.

ULAN BATOR, Aug. 2 (Xinhua) -- The Mongolian government has confirmed equine influenza, a disease that mainly affects horses, broke out in 14 provinces.The government's news office announced the confirmation Tuesday after suspected cases were recently discovered in 18 provinces of the country, where horses still play a key role.According to a Mongolian government report, Mongolian Vice Premier M. Enkhbold called a state emergency situation committee meeting on Monday to respond to the epidemic.Millions of horses will need to be vaccinated, given cases of the disease have been discovered in all but three provinces -- Bayan-Ulgii, Zavkhan and Umnugobi.Equine influenza usually broke out in spring and fall, said an official of the Mongolian veterinarian and breeding bureau. He urged vaccination to be carried out as soon as possible.Mongolia has experienced several equine influenza outbreaks in the past few decades. Outbreaks in Khovd province in 2007 and 2008 caused huge losses to the local livestock industry.Animal husbandry is a dominant factor in the agriculture sector of Mongolia, which has more than 40 million livestock, 2 million of which are horses.

WASHINGTON, Aug. 31 (Xinhua) -- Astronomers using NASA's Chandra X-ray Observatory discovered the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way, NASA announced Wednesday.Approximately 160 million light years from Earth, the pair is the nearest known such phenomenon.The black holes are located near the center of the spiral galaxy NGC 3393. Separated by only 490 light years, the black holes are likely the remnant of a merger of two galaxies of unequal mass a billion or more years ago.Both of the supermassive black holes are heavily obscured by dust and gas, which makes them difficult to observe in optical light. Because X-rays are more energetic, they can penetrate this obscuring material. Chandra's X-ray spectra show clear signatures of a pair of supermassive black holes."If this galaxy weren't so close, we'd have no chance of separating the two black holes the way we have," said Pepi Fabbiano of the Harvard-Smithsonian Center for Astrophysics, who led the study that appeared Wednesday in on-line issue of the journal Nature. "Since this galaxy was right under our noses by cosmic standards, it makes us wonder how many of these black hole pairs we've been missing."Previous observations in X-rays and at other wavelengths indicated that a single supermassive black hole existed in the center of NGC 3393. However, a long look by Chandra allowed the researchers to detect and separate the dual black holes. Both black holes are actively growing and emitting X-rays as gas falls towards them and becomes hotter.When two equal-sized spiral galaxies merge, astronomers think it should result in the formation of a black hole pair and a galaxy with a disrupted appearance and intense star formation. A well-known example is the pair of supermassive black holes in NGC 6240, which is located about 330 million light years from Earth.However, NGC 3393 is a well-organized spiral galaxy, and its central bulge is dominated by old stars. These are unusual properties for a galaxy containing a pair of black holes.

来源：资阳报