吉林全面男性检查多少钱(吉林包皮专科医院) (今日更新中)

LOS ANGELES, July 18 (Xinhua) -- The spacecraft Dawn of the National Aeronautics and Space Administration (NASA) has returned the first close-up image of the giant asteroid Vesta after entering its orbit for the first time last week, the Jet Propulsion Laboratory (JPL) announced on Monday.The image taken for navigation purposes shows Vesta in greater detail than ever before, said JPL in Pasadena, California.On July 15, Dawn became the first probe to enter orbit around an object in the main asteroid belt between Mars and Jupiter.When Vesta captured Dawn into its orbit, there were approximately 9,900 miles (about 16,000 kilometers) between the spacecraft and the asteroid.Vesta is 330 miles (about 530 kilometers) in diameter and the second most massive object in the asteroid belt.NASA's Dawn spacecraft obtained this image with its framing camera on July 17, 2011. It was taken from a distance of about 9,500 miles (15,000 kilometers) away from the protoplanet Vesta. Each pixel in the image corresponds to roughly 0.88 miles (1.4 kilometers). Ground- and space-based telescopes have obtained images of Vesta for about two centuries, but they have not been able to see much detail on its surface."We are beginning the study of arguably the oldest extant primordial surface in the solar system," said Dawn principal investigator Christopher Russell from the University of California, Los Angeles, which is responsible for Dawn's mission science. " This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta's history, as well as logging the onslaught that Vesta has suffered in the intervening eons."Vesta is thought to be the source of a large number of meteorites that fall to Earth. Vesta and its new NASA neighbor, Dawn, are currently approximately 117 million miles (about 188 million kilometers) away from Earth. The Dawn team will begin gathering science data in August.Observations will provide unprecedented data to help scientists understand the earliest chapter of the solar system and pave the way for future human space missions, according to JPL."Dawn slipped gently into orbit with the same grace it has displayed during its years of ion thrusting through interplanetary space," said Marc Rayman, Dawn chief engineer and mission manager at NASA's JPL. "It is fantastically exciting that we will begin providing humankind its first detailed views of one of the last unexplored worlds in the inner solar system."Although orbit capture is complete, the approach phase will continue for about three weeks. During approach, the Dawn team will continue a search for possible moons around the asteroid; obtain more images for navigation; observe Vesta's physical properties; and obtain calibration data.In addition, navigators will measure the strength of Vesta's gravitational tug on the spacecraft to compute the asteroid's mass with much greater accuracy than has been previously available, according to JPL.Dawn will spend one year orbiting Vesta, then travel to a second destination, the dwarf planet Ceres, arriving in February 2015. The mission to Vesta and Ceres is managed by JPL for the agency's Science Mission Directorate in Washington.Dawn is a project of the directorate's Discovery Program, which is managed by NASA's Marshall Space Flight Center in Huntsville, Alaska.

WASHINGTON, June 16 (Xinhua) -- Cells in the human body are constantly being exposed to stress from environmental chemicals or errors in routine cellular processes. While stress can cause damage, it can also provide the stimulus for undoing the damage. New research by a team of scientists at the University of Rochester has unveiled an important new mechanism that allows cells to recognize when they are under stress and prime the DNA repair machinery to respond to the threat of damage.Their findings will be published Friday in journal Science. Cells in the human body are constantly being exposed to stress from environmental chemicals or errors in routine cellular processes. While stress can cause damage, it can also provide the stimulus for undoing the damage.The scientists, led by biologists Vera Gorbunova and Andrei Seluanov, focused on the most dangerous type of DNA damage -- double strand breaks. Unrepaired, this type of damage can lead to premature aging and cancer. They studied how oxidative stress affects efficiency of DNA repair. Oxidative stress occurs when the body is unable to neutralize the highly-reactive molecules, which are typically produced during routine cellular activities.The research team found that human cells undergoing oxidative stress synthesized more of a protein called SIRT6. By increasing SIRT6 levels, cells were able to stimulate their ability to repair double strand breaks. When the cells were treated with a drug that inactivated SIRT6, DNA repair came to a halt, thus confirming the role of SIRT6 in DNA repair. Gorbunova notes that the SIRT6 protein is structurally related to another protein, SIR2, which has been shown to extend lifespan in multiple model organisms."SIRT6 also affects DNA repair when there is no oxidative stress," explains Gorbunova. "It's just that the effect is magnified when the cells are challenged with even small amounts of oxidative stress."SIRT6 allows the cells to be economical with their resources, priming the repair enzymes only when there is damage that needs to be repaired. Thus SIRT6 may be a master regulator that coordinates stress and DNA repair activities, according to Gorbunova.

BEIJING, June 11 (Xinhua) -- The Baidu Charitable Foundation (The Baidu Foundation) and The Bill & Melinda Gates Foundation (The Gates Foundation) founded a strategic charitable alliance here Saturday, in a bid to work for a healthy, smoke-free environment both in China and around the world.Li Yanhong, president of Baidu company, China's top online search engine operator, and Bill Gates, co-chair and trustee of the foundation under the names of the couple, attending the ceremony, both wore a shirt that said, "Say No to Forced Smoking."In his speech at the ceremony, Bill Gates said, "This will be a long-term, open-ended alliance. As a sponsor, Mr. Li and I would like to welcome more partners, and we expect to see more Chinese enterprises and all facets of society to focus on public health issues together."Li Yanhong also addressed the meeting, claiming, "Living healthy and green has become a common pursuit of mankind. We hope the alliance can bring together public efforts for this global cause, so that more people can benefit from our endeavor." ' The alliance's first action is to comply with the government ban on smoking in public places and refuse forced smoking, according to a press release from the foundations.Targeting "forced smokers," the alliance will carry out educational campaign through all channels of media to educate and promote self-awareness about the dangers of forced smoking. Moreover, it will also help existing smokers, especially those who are underage, by sharing scientific methods for quitting.Smoking is one of the world's eight primary causes of death, leading to lung disease, cancer, heart disease, low birth rate, fetal death, tuberculosis, high mortality and many other health issues. Smoking forces many families into poverty by causing both poor health and premature death.China ranks first in tobacco consumption and production in the world. China has 300 million smokers, and one in every three cigarettes smoked in the world is smoked in China. More than half of Chinese smokers are male; and more than 1 million people die from smoking related diseases each year.In addition, China has 740 million "forced smokers," whose health also suffers. The World Health Organization (WHO) notes that there is no safe level of second-hand smoke.This year, China published its 12th Five-Year Plan (2011-2015) that clearly stipulates for "implementing a full-scale ban on smoking in public facilities." This is the first time that tobacco control has been included as part of China's five-year plan for national economic and social development."Rules for Implementation of Public Facilities Health Management Regulations," effective since May 1st, also specifies to "ban smoking at all public indoor facilities," providing legal basis for non-smokers to protect their rights of health and to refuse "involuntary smoking."Aside from tobacco control, the strategic alliance co-founded by the foundations will also collaborate on a series of projects, such as AIDS prevention and control, in a joint effort to promote health for mankind.Founded in 2000, the Gates Foundation currently carries out charity projects in over 100 countries. Since establishing the Beijing Representative Office in 2007, the Gates Foundation has supported a range of health and development projects in China, including the advocacy of smoke-free environment, AIDS and tuberculosis prevention and control, and agricultural development and research projects.Launched in 2010, the Baidu Foundation is committed to use information technology for support of youth and disadvantaged groups, focus on the environment and promote social harmony.Ever since Baidu was founded, Li has actively pushed for tobacco control within the enterprise and the industry. He is the only Chinese member of the United Nation AIDS Prevention Senior Committee and also board member of the HuaXia Charity Foundation.

THE HAGUE, June 1(Xinhua) -- Five people in the Netherlands have been sickened with an unusual strain of the E. coli bacteria, the institute for public health (RIVM) reported Wednesday.Of the five patients, four also suffered from intestinal problems and renal failure. The five who are infected all had recently been in Germany.The patients were infected with enterohaemorrhagic E.coli, or EHEC, a particularly deadly strain of the common bacteria found in the digestive systems of cows, humans and other mammals.The outbreak has hit at least eight European countries but virtually all of the sick people either live in Germany or recently traveled there.Medical authorities appeared no closer to discovering either the source of the infection or the mystery at the heart of the outbreak: why the unusual strain of the E. coli bacteria appears to be causing so many cases of hemolytic uremic syndrome, which attacks the kidneys and can cause seizures, strokes and comas.Earlier this week German researchers showed that Dutch cucumbers were not the cause of the contamination."It is essential to quickly find the source, as long as that is not found, the contamination can spread. It's a very aggressive bacteria and many people are seriously ill," a RIVM spokesman said.

WASHINGTON, June 15 (Xinhua) -- Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe, the U.S. National Aeronautics and Space Administration (NASA) said Wednesday in a statement.The discovery from NASA's Chandra X-ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies.By pointing Chandra at a patch of sky for more than six weeks, astronomers obtained what is known as the Chandra Deep Field South (CDFS). When combined with very deep optical and infrared images from NASA's Hubble Space Telescope, the new Chandra data allowed astronomers to search for black holes in 200 distant galaxies, from when the universe was between about 800 million to 950 million years old."Until now, we had no idea what the black holes in these early galaxies were doing, or if they even existed," said Ezequiel Treister of the University of Hawaii, lead author of the study to appear Thursday in journal Nature. "Now we know they are there, and they are growing like gangbusters."The super-sized growth means that the black holes in the CDFS are less extreme versions of quasars -- very luminous, rare objects powered by material falling onto supermassive black holes. However, the sources in the CDFS are about a hundred times fainter and the black holes are about a thousand times less massive than the ones in quasars.The observations found that between 30 and 100 percent of the distant galaxies contain growing supermassive black holes. Extrapolating these results from the small observed field to the full sky, there are at least 30 million supermassive black holes in the early universe. This is a factor of 10,000 larger than the estimated number of quasars in the early universe."It appears we've found a whole new population of baby black holes," said co-author Kevin Schawinski of Yale University. "We think these babies will grow by a factor of about a hundred or a thousand, eventually becoming like the giant black holes we see today almost 13 billion years later."

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