濮阳高考应届补习班正规联系电话(灞桥区老师靠谱的联系方式) (今日更新中)

WASHINGTON, May 17 (Xinhua) -- The U.S. National Aeronautics and Space Administration (NASA) announced Tuesday that the international Aquarius/SAC-D observatory will be launched on June 9, to study interactions between ocean circulation, the water cycle and climate by measuring ocean surface salinity.Engineers at Vandenberg Air Force Base in California are performing final tests before mating the satellite to its Delta II rocket. The mission is a collaboration between NASA and Argentina' s space agency, with participation from Brazil, Canada, France and Italy.In addition to Aquarius, the primary instrument, the observatory carries seven other instruments that will collect environmental data for a wide range of applications, including studies of natural hazards, air quality, land processes and epidemiology.The mission will make NASA's first space observations of the concentration of dissolved salt at the ocean surface. Aquarius' observations will reveal how salinity variations influence ocean circulation, trace the path of freshwater around our planet, and help drive Earth's climate. The ocean surface constantly exchanges water and heat with Earth's atmosphere. Approximately 80 percent of the global water cycle that moves freshwater from the ocean to the atmosphere to the land and back to the ocean happens over the ocean.Salinity plays a key role in these exchanges. By tracking changes in ocean surface salinity, Aquarius will monitor variations in the water cycle caused by evaporation and precipitation over the ocean, river runoff, the freezing and melting of sea ice. Salinity also makes seawater denser, causing it to sink, where it becomes part of deep, interconnected ocean currents. This deep ocean "conveyor belt" moves water masses and heat from the tropics to the polar regions, helping to regulate Earth's climate."Salinity is the glue that bonds two major components of Earth' s complex climate system: ocean circulation and the global water cycle," said Aquarius Principal Investigator Gary Lagerloef of Earth & Space Research in Seattle in a statement. "Aquarius will map global variations in salinity in unprecedented detail, leading to new discoveries that will improve our ability to predict future climate."Aquarius will measure salinity by sensing microwave emissions from the water's surface with a radiometer instrument. These emissions can be used to indicate the saltiness of the surface water, after accounting for other environmental factors. Salinity levels in the open ocean vary by only about five parts per thousand, and small changes are important. Aquarius uses advanced technologies to detect changes in salinity as small as about two parts per 10,000, equivalent to a pinch (about one-eighth of a teaspoon) of salt in a gallon of water.Aquarius will map the entire open ocean every seven days for at least three years from 408 miles (657 kilometers) above Earth. Its measurements will produce monthly estimates of ocean surface salinity with a spatial resolution of 93 miles (150 kilometers). The data will reveal how salinity changes over time and from one part of the ocean to another.

JINAN, May 14 (Xinhua) -- Chinese scientists said Saturday that they have found a new species of giant theropod dinosaur in the eastern province of Shandong.The new species, described as a close relative of Tyrannosaurus rex (T. rex), has been named "Zhuchengtyrannus magnus". Paleontological experts found it has unique upper jawbones after examining the skull and jawbones discovered in the city of Zhucheng.It was estimated to be about 11 meters long and 4 meters tall, weighing close to 7 tonnes."We discovered two kinds of tyrannosaurus fossils here and the identity of the other one still remains unclear," said Xu Xing, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology under the Chinese Academy of Sciences."We've named the new genus Zhuchengtyrannus magnus, which means the 'Tyrant from Zhucheng' because the bones were found in Zhucheng," Xu said.The bones were a few centimeters smaller than the similar bones in the largest T. Rex specimen, so there was no doubt that Zhuchengtyrannus was a huge tyrannosaur, Xu said.According to Xu, Zhuchengtyrannus magnus belonged to a specialized group of gigantic theropods called tyrannosaurines which existed in North America and eastern Asia during the Late Cretaceous Period that dated back about 65 to 99 million years.All tyrannosaurs were carnivorous, bipedal animals that generally had small arms and large skulls. Among the tyrannosaurs, the tyrannosaurines were the largest and characterized by having just two fingers on each hand and large powerful jaws to deliver a bone crushing bite. They were likely both predators and scavengers.The fossil quarry in Zhucheng contains one of the largest concentrations of dinosaur bones in the world. At least 10 dinosaur species have been found in three rounds of excavations since the 1960s, including Tyrannosaurus and Hadrosaurs.

BEIJING, May 25 (Xinhua) -- A researcher with the Chinese Academy of Agricultural Sciences (CAAS) said Wednesday that plant hormones, if used properly, are not a risk to human health."Irregular use of plant growth substances may cause plants to grow excessively fast or affect the taste, but will not cause harm to human health," Ye Zhihua said in an interview with Xinhua.His remarks come after media reports in China about "exploding watermelons," caused by the excessive use of phytohormone, have aroused public concern over the safety of hormones that stimulate plant growth.Ye said plant hormones used to promote growth have the same or similar effects as natural plant hormones, and fruit and vegetables sold at the market carried limited residue of the hormones.More than 100 types of plant hormones, such as ethephon and gibberellin acid, are used in agriculture and forestry sectors around the world, Ye said, adding 38 types of plant hormones have been registered in China.For example, seven plant hormones including thidiazuron and nucleotide are approved for use on cucumbers in China. The purpose is to stimulate the growth of female flowers and increase fruit yields, Ye said.Ye added that China places plant hormones in the category of pesticides control, which means the hormones are subject to strict management from production to utilization.

BEIJING, Jan. 22 (Xinhua) -- Chinese President Hu Jintao's latest state visit to the United States bore rich fruit and opened a new chapter of cooperation between the two countries, Foreign Minister Yang Jiechi said Saturday.The tour, from Tuesday through Friday, came at the beginning of the second decade of the 21st century, on the 40th anniversary of the resumption of contact between the two countries and on the opening year of China's 12th five-year plan for national socioeconomic development, Yang noted.Meanwhile, the international situation was witnessing deep and complicated changes, and the China-U.S. relationship was forging ahead with increasing momentum while inevitably encountering some differences and disputes, he said.Against such a backdrop, the Chinese president held frank and in-depth talks with his U.S. counterpart, Barack Obama, and many other senior political figures, and reached important consensus on bilateral relations and a host of major regional and global affairs, Yang said.During the tightly scheduled trip, which saw Hu attend nearly 20 events in Washington and Chicago within 68 hours, the Chinese leader also reached out to the U.S. public, conveying China's resolution to advance China-U.S. ties, highlighting China's commitment to peaceful development and presenting China's image of peace, development, opening-up and progress, Yang said.The U.S. and international media, he added, attached great importance to and spoke highly of Hu's trip, hailing it as a historic visit at a crucial moment and whose significance was manifested partly in the top level reception with full pomp and ceremony given by the U.S. government.In summary, the latest step in China-U.S. diplomacy achieved rich results and cast a far-reaching influence not only upon the two countries themselves but upon the whole world, the Chinese foreign minister said.

LOS ANGELES, May 12 (Xinhua) -- A subsurface ocean of molten or partially molten magma exists beneath the surface of Jupiter's volcanic moon Io, the Jet Propulsion Laboratory (JPL) said on Thursday."The finding heralds the first direct confirmation of this kind of magma layer at Io and explains why the moon is the most volcanic object known in the solar system," JPL said in a press release posted on its website.The finding was based on new data analysis from NASA's Galileo spacecraft, said JPL.The research was conducted by scientists at the University of California, Los Angeles; the University of California, Santa Cruz;, and the University of Michigan, Ann Arbor. The study is published this week in the journal Science, JPL said."Scientists are excited we finally understand where Io's magma is coming from and have an explanation for some of the mysterious signatures we saw in some of the Galileo's magnetic field data," said Krishan Khurana, lead author of the study and former co- investigator on Galileo's magnetometer team at UCLA."It turns out Io was continually giving off a 'sounding signal' in Jupiter's rotating magnetic field that matched what would be expected from molten or partially molten rocks deep beneath the surface."Io produces about 100 times more lava each year than all the volcanoes on Earth, according to data released by JPL in Pasadena, Los Angeles.While Earth's volcanoes occur in localized hotspots like the "Ring of Fire" around the Pacific Ocean, Io's volcanoes are distributed all over its surface, JPL said, adding that a global magma ocean about 30 to 50 km beneath Io's crust helps explain the moon's activity."It has been suggested that both the Earth and its moon may have had similar magma oceans billions of years ago at the time of their formation, but they have long since cooled," said Torrence Johnson, a former Galileo project scientist based at JPL, an affiliation with NASA."Io's volcanism informs us how volcanoes work and provides a window in time to styles of volcanic activity that may have occurred on the Earth and moon during their earliest history," said Johnson, who was not directly involved in the study.NASA's Voyager spacecraft discovered Io's volcanoes in 1979, making that moon the only body in the solar system other than Earth known to have active magma volcanoes. The energy for the volcanic activity comes from the squeezing and stretching of the moon by Jupiter's gravity as Io orbits the largest planet in the solar system.Galileo was launched in 1989 and began orbiting Jupiter in 1995. Unexplained signatures appeared in magnetic field data from Galileo flybys of Io in October 1999 and February 2000. After a successful mission, the spacecraft was intentionally sent into Jupiter's atmosphere in 2003.

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