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天津市武清区龙济治疗阴囊潮湿吗
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发布时间: 2025-05-30 21:29:19北京青年报社官方账号
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  天津市武清区龙济治疗阴囊潮湿吗   

LOS ANGELES, June 23 (Xinhua) -- The sun and its inner planets may have formed differently than previously thought, NASA's Jet Propulsion Laboratory (JPL) said on Thursday.Data revealed differences between the sun and planets in oxygen and nitrogen, which are two of the most abundant elements in our solar system, said JPL in Pasadena, Los Angeles.Although the difference is slight, the implications could help determine how our solar system evolved, JPL said.NASA researchers drew the conclusion after analyzing samples returned by NASA's 2004 Genesis mission, according to JPL.The air on Earth contains three different kinds of oxygen atoms which are differentiated by the number of neutrons they contain. Nearly 100 percent of oxygen atoms in the solar system are composed of O-16, but there are also tiny amounts of more exotic oxygen isotopes called O-17 and O-18. Researchers studying the oxygen of Genesis samples found that the percentage of O-16 in the sun is slightly higher than on Earth or on other terrestrial planets. The other isotopes' percentages were slightly lower."We found that Earth, the moon, as well as Martian and other meteorites which are samples of asteroids, have a lower concentration of the O-16 than does the sun," said Kevin McKeegan, a Genesis co-investigator from University of California, Los Angeles (UCLA) and the lead author of one of two papers published this week in Science journal. "The implication is that we did not form out of the same solar nebula materials that created the sun -- just how and why remains to be discovered." Another paper detailed differences between the sun and planets in the element nitrogen. Like oxygen, nitrogen has one isotope, N- 14, that makes up nearly 100 percent of the atoms in the solar system, but there is also a tiny amount of N-15. Researchers studying the same samples saw that when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition. As is the case for oxygen, Earth and the rest of the inner solar system are very different in nitrogen."These findings show that all solar system objects including the terrestrial planets, meteorites and comets are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co- investigator from Petrographic and Geochemical Research Center in Fracne and the lead author of the other new Science paper. " Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system."Data were obtained from analysis of samples Genesis collected from the solar wind, or material ejected from the outer portion of the sun. This material can be thought of as a fossil of our nebula because the preponderance of scientific evidence suggests that the outer layer of our sun has not changed measurably for billions of years."The sun houses more than 99 percent of the material currently in our solar system, so it's a good idea to get to know it better, " said Genesis Principal Investigator Don Burnett of the California Institute of Technology, Pasadena, California. "While it was more challenging than expected, we have answered some important questions, and like all successful missions, generated plenty more."Genesis was launched in August 2000. The spacecraft traveled to Earth's L1 Lagrange Point about one million miles from Earth, where it remained for 886 days between 2001 and 2004, passively collecting solar-wind samples.JPL managed the Genesis mission for NASA's Science Mission Directorate, Washington. The Genesis mission was part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Alasca.

  天津市武清区龙济治疗阴囊潮湿吗   

People look at a W154 Mercedes Benz racing car at a vintage car show marking the German car maker's 125 anniversary at the former Tempelhof airport in Berlin, August 27, 2011.

  天津市武清区龙济治疗阴囊潮湿吗   

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.

  

BEIJING, Aug. 3 (Xinhuanet) -- NASA Tuesday confirmed a 4-foot in diameter sphere debris as a fuel tank that was part of the space shuttle Columbia's electrical power system,according to U.S. news reports.NASA engineers identified the 4-foot piece of spherical debris as one of the18 tanks that held chilled oxygen and hydrogen used by the shuttle's electricity-generating fuel cells.This Aug. 1, 2011 handout photo provided by the Nacogdoches Police Department shows a 4-feet in diameter sphere found in Lake Nacogdoches, Texas on Monday, Aug. 1. Police say low water levels at the lake during the drought have led to recovery of a container-like object that could be from space shuttle Columbia. The shuttle broke apart and burned in February 2003, scattering remnants over East TexasPolice in the city of Nacogdoches, about 160 miles northeast of Houston, said Monday the low water levels of Lake Nacogdoches during the record drought revealed an unexpected object that could be from space shuttle Columbia. The shuttle broke apart and burned as it re-entered the atmosphere on February 1, 2003.The tank will be moved to the Kennedy Space Center, where the rest of the Columbia is stored. Approximately 40 percent of the spacecraft has been recovered.

  

WELLINGTON, July 29 (Xinhua) -- Scientists from around the world will gather on the east coast of New Zealand next week to discuss proposals to study "silent" earthquakes by drilling into the seabed.Silent quakes, also known as slow slip events, occur on the boundaries of the earth's tectonic plates, where one plate dives under another in areas known as subduction zones, and are slower than normal quakes, taking weeks or months to occur rather than seconds, and are rarely felt on the surface.About 70 scientists from 10 countries will convene in the city of Gisborne, which lies near the site of a major fault line and where scientists first identified silent earthquakes in 2002.Slow-slip events were first discovered with the advent of new measurement technologies on the west coast of Canada about 15 years ago and have since been recorded at about a dozen locations around the world, including four sites around New Zealand, said a spokesperson for New Zealand's Institute of Geological and Nuclear Sciences (GNS Science).About eight slow-slip episodes have occurred under Gisborne since 2002 at roughly two-year intervals.Scientists have proposed numerous theories to explain the phenomenon, but testing the theories is difficult as silent quakes happen many kilometers below ground."The best way to understand the true cause of slow-slip events is to drill into and sample the area on the plate boundary fault where they are known to occur, and monitor a whole range of physical and chemical properties at the plate interface," said Laura Wallace, of GNS Science.

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