临沧月经没来一个月了(临沧急性盆腔炎的诊断) (今日更新中)

You can think of NASA's Discovery program as a sort of outer-space American Idol: every few years the agency invites scientists to propose unmanned planetary missions. The projects have to address some sort of fundamental science question, and (this is the tough part) they have to be relatively cheap to pull off — say, half a billion dollars or so. Then the proposals go through a grueling competition before judges who aren't as nasty as Simon Cowell but who are every bit as tough. The one left standing at the end gets the equivalent of a recording contract: NASA supplies the funding and the launch vehicle, and away the winner goes — to orbit Mercury, as the Messenger spacecraft is doing right now; or to rendezvous with a couple of asteroids, as the Dawn mission will start doing this July; or to smash into a comet on purpose, a feat achieved by Deep Impact in 2005, a mission not to be confused with the movie of the same name. Now it's time for the next contenders. NASA has just announced that the first round of the latest Discovery competition is over, with three entries out of 28 moving on to the finals. They are, in increasing distance from Earth: the Geophysical Monitoring Station (GEMS) lander, which would use seismometers to study the interior of Mars; the Comet Hopper, which would do just that, leaping from place to place across the surface of Comet 46P/Wirtanen to see how different parts of the tumbling body react to heating by the sun; and the Titan Mare Explorer (TiME), which would plop into a sea of liquid hydrocarbons on Saturn's moon Titan — the first oceangoing vessel ever to set sail on another world. If you had to come up with a theme that ties all three missions together, it would be "origins." The Titan explorer, for example, will be studying a place that — in a crude way, at least — resembles the early planet Earth at a time when life arose here. Titan, with a thick atmosphere and a bizarro-world form of weather featuring toxic winds and hydrocarbon rain, is home to a mix of complex chemistry, complete with organic molecules. The oceans provide a medium in which the molecules can move around and interact with each other. It's even conceivable, though clearly a long shot, that some form of microscopic life already exists on this frigid moon. The Mars lander, by contrast, would visit a place where the seas — plain water in this case — vanished long ago. But the mission of GEMS goes far deeper than that. By analyzing Marsquakes on the Red Planet, GEMS will try to get a handle on what the interior of Mars is like. Scientists don't currently know whether the planet's core is liquid, like Earth's, or solid, or some mushy consistency in between. It all depends on how efficiently Mars has cooled since it formed 4.5 billion years ago, and that depends in turn on the planet's internal structure. "That's the mission," says Bruce Banerdt, of NASA's Jet Propulsion Laboratory, the lead scientist for GEMS. "We want to understand how Mars was built." Along with sensitive seismographic equipment, GEMS will drill down about 20 ft. (6 m) with a thermometer-equipped probe, trying to figure out how quickly the temperature rises with depth. "That will let us extrapolate all the way down to the center," Banerdt says, "which will tell us how fast Mars is cooling."

BEIJING, Jan. 30 (Xinhua) -- Chinese Vice Premier Li Keqiang Sunday urged scientists to learn from foreign experiences and increase their participation in international cooperation in polar and oceanic exploration.Li made the remarks after meeting with members of China's 27th Chinese Antarctic expedition team, the 22nd oceanic expedition, and scientists working in the country's Antarctic and Arctic stations via video and telephone.Li said many countries nowadays attached great importance to polar and oceanic exploration, and international competition had grown in promoting the peaceful utilization of these resources.Chinese Vice Premier Li Keqiang (R, front) shakes hands with a senior Chinese explorer in Beijing, capital of China, Jan. 30, 2011. Li conveyed Spring Festival greetings while meeting with members of China's 27th Chinese Antarctic expedition team, the 22nd oceanic expedition, and scientists working in the country's Antarctic and Arctic stations via video and telephone on Sunday."We are confident and capable of constantly improving our working conditions to conduct polar and oceanic exploration, and winning the initiative in this sector's future development," Li said.Li said the country would work to promote its marine economy and safeguard marine ecosystems, as well, and make full use of the achievements made in explorations to make reasonable development and utilization of ocean resources.China would also ensure the security of ocean passages, and safeguard its marine rights and interests, the vice premier said.Li also conveyed New Years greetings to the scientists for conducting research away from their homeland and families, and applauded their contribution to the country's progress in polar and oceanic research areas.

CAIRO, Jan. 23 (Xinhua) -- As part of bilateral efforts to enhance cultural cooperation between the two great civilizations, China, as the Guest of Honor, will participate in the 43rd Cairo International Book Fair in Egypt."An outstanding Chinese delegation will attend the fair to inform the Egyptian people all about Chinese culture," said Chen Dongyun, cultural counsellor of the Chinese Embassy in Egypt.Some 248 publishers, 13 renowned scholars, writers and artists will display about 10,000 books about the achievements made by China in various fields such as politics, economy, science and technology, and culture.The fair, the most important of its kind in the Arab region, will be held on Jan. 29 through Feb. 8 in the Cairo International Conference Center. The annual fair began in 1969.The Chinese hall in the center covers an area of 1,400 square meters, with special areas allocated for a variety of exhibitions about the history of the evolution of Chinese characters, photos reflecting Sino-Egypt friendship and landscape of modern China and intangible cultural heritage.The fair also includes a seminar featuring literature and translation among Chinese and Egyptian writers and artists and a week-long film show in which six Chinese films with Arabic subtitles will be introduced to the audience.Chinese participation reflected the common consensus of the leaders of the two countries to deepen mutual understanding and friendship and will serve to promote the sound and sustainable development of bilateral relations, Chen said.Zhang Jichen, vice president of China National Publications Import and Export (Group) Corporation, which is in charge of the organization of the Chinese activities at the fair, said a cooperation agreement between the General Administration of Press and Publication of China and Egypt's Ministry of Culture.China will also present some 1,000 high-quality books to the National Library and Archives of Egypt and the Alexandria Library.The fair is expected to attract 632 publishers from 29 countries, including 17 in the Middle East. More than two million visitors participate in the fair each year.

BRASILIA, March 15 (Xinhua) -- A nationwide program aimed at providing internet access to 80 percent of the country's population by 2014 is forging ahead in Brazil, Communications Minister Paulo Bernardo said on Tuesday.The National Broadband Plan (PNBL), with participation of 13 ministries, is coordinated by Bernardo, who explained details about the project on Tuesday along with Joao Santana, president of Telebras, the state-owned enterprise responsible for managing the project.The authorities have criticized companies that offer internet service for failing to spread internet use in Brazil, offering an expensive service with prices amounting to about 50 U.S. dollars monthly, inaccessible to low-income families."We ended 2010 with 34 percent of Brazilian households with Internet access, and service is also very poor. Almost half of connections are of 256 mbps. We are out-of-date, with the aggravating circumstance that the connections are very expensive," Bernardo said.To speed up the process, the government started negotiating with concessionaire phone companies to improve the service quality and lower the price to about 30 reais (18 dollars), which would allow 80 percent of the population to access internet."During (former president) Lula da Silva's government, we developed a program to interconnect all schools with internet access, but we also want the private sector to do its share," he said.

来源：资阳报