海南肘关节剖面模型(河南标准乳牙模型) (今日更新中)

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, Sept. 2 (Xinhua) -- A late-season potato blight has been detected on farms in Alaska, only the fourth time the disease appear in the U.S. state since 1995, local media reported on Friday.The disease was found this week in the fields of potato producers in cities of Delta Junction and Palmer, according to the Fairbanks Daily News-Miner, Alaska's second largest daily newspaper.Farmers in both fields are working to prevent the spread of the blight, a fungus-like disease that can kill plants in the field or cause potatoes to rot in storage, the newspaper reported.Growers have been asked to kill all affected plants within 100 feet, and plant samples from both sites will be examined to identify what type of late blight is involved.Experts said that blight can be controlled through the use of fungicides, but the cool, damp weather this summer in the areas has created an ideal environment for the disease to spread.Although Alaska's potato crop is tiny compared to other U.S. states, it has been viewed as a possible global source of seed potatoes in recent years because it is largely free of disease.A local university has explored partnerships with Chinese growers to export certified seed potatoes, noted the Fairbanks Daily News-Miner report.

Robots perform a dance in a competition in Mudanjiang, northeast China's Heilongjiang Province, July 24, 2011. A nationwide robot competition was kicked off in the city on Sunday, with participants from 50 colleges and universities

WASHINGTON, June 6 (Xinhua) -- Forests in many regions are becoming larger carbon sinks thanks to higher density, U.S. and European researchers say in a new report.In Europe and North America, increased density significantly raised carbon storage despite little or no expansion of forest area, according to the study, led by Aapo Rautiainen of the University of Helsinki, Finland, and published Monday in the on- line, open-access journal PLoS One.Even in the South American nations studied, more density helped maintain regional carbon levels in the face of deforestation.The researchers analyzed information from 68 nations, which together account for 72 percent of the world's forested land and 68 percent of reported carbon mass. They conclude that managing forests for timber growth and density offers a way to increase stored carbon, even with little or no expansion of forest area."In 2004 emissions and removals of carbon dioxide from land use, land-use change and forestry comprised about one fifth of total emissions. Tempering the fifth by slowing or reversing the loss of carbon in forests would be a worthwhile mitigation. The great role of density means that not only conservation of forest area but also managing denser, healthier forests can mitigate carbon emission," says Rautiainen.

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.”

来源：资阳报