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2025-06-03 02:45:42
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  云南小脑放大模型   

LOS ANGELES, July 22 (Xinhua) -- Two teams of astronomers have discovered the largest and farthest reservoir of water ever detected in the universe, NASA's Jet Propulsion Laboratory (JPL) said on Friday.The water, equivalent to 140 trillion times all the water in the world's ocean, surrounds a huge, feeding black hole, called a quasar, more than 12 billion light-years away, according to JPL in Pasadena, California."The environment around this quasar is very unique in that it's producing this huge mass of water," said Matt Bradford, a scientist at JPL. "It's another demonstration that water is pervasive throughout the universe, even at the very earliest times. "This artist's concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the central black hole, with clouds of charged gas above and below. X-rays emerge from the very central region, while thermal infrared radiation is emitted by dust throughout most of the torus. While this figure shows the quasar's torus approximately edge-on, the torus around APM 08279+5255 is likely positioned face-on from our point of view.A quasar is powered by an enormous black hole that steadily consumes a surrounding disk of gas and dust. As it eats, the quasar spews out huge amounts of energy. Both groups of astronomers studied a particular quasar called APM 08279+5255, which harbors a black hole 20 billion times more massive than the sun and produces as much energy as a thousand trillion suns.Astronomers expected water vapor to be present even in the early, distant universe, but had not detected it this far away before. There's water vapor in the Milky Way, although the total amount is 4,000 times less than in the quasar, because most of the Milky Way's water is frozen in ice. Water vapor is an important trace gas that reveals the nature of the quasar. In this particular quasar, the water vapor is distributed around the black hole in a gaseous region spanning hundreds of light-years in size (a light-year is about six trillion miles).Its presence indicates that the quasar is bathing the gas in X- rays and infrared radiation, and that the gas is unusually warm and dense by astronomical standards, JPL said.Although the gas is at a chilly minus 63 degrees Fahrenheit ( minus 53 degrees Celsius) and is 300 trillion times less dense than Earth's atmosphere, it's still five times hotter and 10 to 100 times denser than what's typical in galaxies like the Milky Way, said JPL.Measurements of the water vapor and of other molecules, such as carbon monoxide, suggest there is enough gas to feed the black hole until it grows to about six times its size, JPL said.Whether this will happen is not clear, the astronomers say, since some of the gas may end up condensing into stars or might be ejected from the quasar.Bradford's team made their observations starting in 2008, using an instrument called "Z-Spec" at the California Institute of Technology's (Caltech's) Submillimeter Observatory, a 33-foot (10- meter) telescope near the summit of Mauna Kea in Hawaii. Follow-up observations were made with the Combined Array for Research in Millimeter-Wave Astronomy (CARMA), an array of radio dishes in the Inyo Mountains of Southern California.The second group, led by Dariusz Lis, senior research associate in physics at Caltech and deputy director of the Caltech Submillimeter Observatory, used the Plateau de Bure Interferometer in the French Alps to find water. In 2010, Lis's team serendipitously detected water in APM 8279+5255, observing one spectral signature.Bradford's team was able to get more information about the water, including its enormous mass, because they detected several spectral signatures of the water, according to JPL.

  云南小脑放大模型   

SAN FRANCISCO, July 12 (Xinhua) -- Facebook and Time Warner announced on Tuesday that they are teaming up to launch a wide- ranging, major cross-platform partnership initiative to fight bullying.The multi-media campaign, named "Stop Bullying: Speak Up" after the original anti-bullying initiative by Time Warner's Cartoon Network, will integrate broadcast, print, online and social media to educate parents, teachers and youth about the actions that will help protect young people from the impact of bullying, the two said in a joint statement.As part of the initiative, Facebook is scheduled to launch an interactive application in the back-to-school season this fall, which will enable educators, parents, and kids to make a personal commitment to help stop bullying."We care deeply about the safety of our nation's children and are proud to be partnering with Time Warner to raise awareness of bullying," Sheryl Sandberg, Facebook's chief operating officer, said in the statement."We believe that by working together with parents and teachers, we can teach young people to speak up and stop bullying," she added.Time Warner is also planning to expand its multiplatform efforts to communicate the anti-bullying message to an broader audience.It said in October, three of its magazines -- People, Sports Illustrated and Time -- and their affiliated websites will feature editorial content that highlights the problem of bullying and innovative programs and measures being taken to combat it.In partnership with Facebook, CNN's Anderson Cooper will also host a new town hall, which is scheduled to air in October and will be dedicated to discussing bullying issues confronting kids today as well as discussions with experts to teach adults on coping with the bullying epidemic."I'm confident that through our multiplatform approach and combined resources we can inspire even more people to take action against bullying," said Jeff Bewkes, Time Warner's chairman and chief executive officer.

  云南小脑放大模型   

THE HAGUE, Aug. 16 (Xinhua) -- ESBL-enzymes, which are known for their ability to stop the effects of antibiotics, can directly pass from chicken to people, said a research published on Tuesday.Veterinary researcher Dik Mevius of the Wageningen University released the finding in the magazine Resource.The research group led by Mevius has isolated six ESBL-genes varieties and compared them to bacteria found on hospital patients, on super market poultry and in laying batteries. In 35 percent of all cases, they discovered a match of 100 percent.Bacteria like Klebsiella on E. coli can produce the ESBL-enzymes. A healthy person will not feel any effect, but people with a lower immune system can get very sick. In areas like a hospital, the infection can easily spread."The main concern is that the enzyme resists the most used antibiotics, which makes the treatment of infected persons difficult," said Mevius.According to Mevius, 94 percent of supermarket poultry carries the enzyme, but all enzymes will be killed during the heating process of cooking.

  

BEIJING, June 12 (Xinhua) -- A senior Chinese official has called the country's police to better serve the people when the Communist Party of China (CPC) is meeting the 90th founding anniversary.Zhou Yongkang, member of the Standing Committee of the Political Bureau of the CPC Central Committee, made the remark on Sunday evening in meeting with top 10 favorite police officers selected through a nationwide vote.The Ministry of Public Security (MOPS) and the China Central Television have jointly conducted My Favorite Police Officer Competition in the past eight years.This year's winners include 75-year-old detective Wu Guoqing, network security police officer Li Qing from Jiangsu Province, traffic police officer Wu Hao of Miao Nationality from Hunan Province, female SWAT team leader Pan Qin from Guizhou Province.Zhou said that this year's competition attracted more than 150 million online voters which means more and more people are supporting the activity, and all winners should cherish the honor and better serve the people on their own posts.The official called on police officers around the country to learn from the 10 favarite officers and other winners in the competition who have all made outstanding contribution to the security of the people and society.

  

LOS ANGELES, June 17 (Xinhua) -- The size of low-oxygen zones created by respiring bacteria is extremely sensitive to changes in depth caused by oscillations in climate, thus posing a distant threat to marine life, a new study suggests."The growth of low-oxygen regions is cause for concern because of the detrimental effects on marine populations -- entire ecosystems can die off when marine life cannot escape the low- oxygen water," said lead researcher Curtis Deutsch, assistant professor of atmospheric and oceanic sciences at University of California, Los Angeles."There are widespread areas of the ocean where marine life has had to flee or develop very peculiar adaptations to survive in low- oxygen conditions," Deutsch said in the study to be published in an upcoming print edition of the journal Science.A team led byDeutsch used a specialized computer simulation to demonstrate for the first time that fluctuations in climate can drastically affect the habitability of marine ecosystems.The study also showed that in addition to consuming oxygen, marine bacteria are causing the depletion of nitrogen, an essential nutrient necessary for the survival of most types of algae."We found there is a mechanism that connects climate and its effect on oxygen to the removal of nitrogen from the ocean," Deutsch said. "Our climate acts to change the total amount of nutrients in the ocean over the timescale of decades."Low-oxygen zones are created by bacteria living in the deeper layers of the ocean that consume oxygen by feeding on dead algae that settle from the surface. Just as mountain climbers might feel adverse effects at high altitudes from a lack of air, marine animals that require oxygen to breathe find it difficult or impossible to live in these oxygen-depleted environments, Deutsch said.Sea surface temperatures vary over the course of decades through a climate pattern called the Pacific Decadal Oscillation, during which small changes in depth occur for existing low-oxygen regions, Deutsch said. Low-oxygen regions that rise to warmer, shallower waters expand as bacteria become more active; regions that sink to colder, deeper waters shrink as the bacteria become more sluggish, as if placed in a refrigerator."We have shown for the first time that these low-oxygen regions are intrinsically very sensitive to small changes in climate," Deutsch said in remarks published Friday by the American Association for the Advancement of Science on its website. "That is what makes the growth and shrinkage of these low-oxygen regions so dramatic."Molecular oxygen from the atmosphere dissolves in sea water at the surface and is transported to deeper levels by ocean circulation currents, where it is consumed by bacteria, Deutsch said."The oxygen consumed by bacteria within the deeper layers of the ocean is replaced by water circulating through the ocean," he said. "The water is constantly stirring itself up, allowing the deeper parts to occasionally take a breath from the atmosphere."A lack of oxygen is not the only thing fish and other marine life must contend with, according to Deutsch. When oxygen is very low, the bacteria will begin to consume nitrogen, one of the most important nutrients that sustain marine life."Almost all algae, the very base of the food chain, use nitrogen to stay alive," Deutsch said. "As these low-oxygen regions expand and contract, the amount of nutrients available to keep the algae alive at the surface of the ocean goes up and down. "Understanding the causes of oxygen and nitrogen depletion in the ocean is important for determining the effect on fisheries and fish populations, he said.

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