中山大便带血两周(中山拉大便正出血) (今日更新中)

LOS ANGELES, June 5 (Xinhua) -- A latest study has found no evidence that screening for ovarian cancer may reduce the risk of dying from the disease, it was reported on Sunday.Screening, however, does increase the likelihood of unnecessary invasive procedures, according to researchers at the University of Utah.The researchers presented their findings at an on-going meeting of the American Society of Clinical Oncology in Chicago, The Los Angeles Times said.Researchers studied 78,216 women, ages 55 to 74, who participated in the National Cancer Institute's Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Half of the women received the usual care from their OB-gyns, and half received a CA 125 screening every year for six years and an ultrasound every year for four years. They were then followed for a maximum of 12 years.The researchers observed 212 ovarian cancers in the screened group and 176 in the normal care group. There were 118 ovarian cancer deaths in the screened group and 100 in the normal care group. The differences were not statistically significant. Overall, there were 2,924 deaths from all causes in the screened group and 2,914 in the normal care group.But the researchers also observed that 3,285 women had false- positive diagnoses from the screening. Among those, 1,080 underwent surgery that included an oophorectomy (surgical removal of one or both ovaries). Fifteen percent of those who had surgery developed major complications as a result. Overall, 1,771 women in the screened group (7.7 percent) had an oophorectomy, compared with 1,304 in the normal care group (5.8 percent)."We conclude that annual screening for ovarian cancer ... does not reduce disease-specific mortality in women at average risk for ovarian cancer but does increase invasive medical procedures and associated harms," the researchers said in the study.New data presented at the meeting also showed that the widely used cancer drug Avastin can improve treatment of ovarian cancer, The Times said.About 21,880 American women are diagnosed with ovarian cancer each year and about 13,850 die from it, according to the American Cancer Society. Because it produces few symptoms, the disease is typically not diagnosed until it has become advanced and spread throughout the body. As a result, five-year survival is only about 30 percent, and the disease is one of the five most deadly cancers among women. Being able to detect the cancer at an earlier stage when it might be more curable could thus, theoretically, improve the survival rate.The tests most commonly used to detect ovarian cancer include a transvaginal ultrasound to look for tumor masses and a blood test that screens for increased levels of a tumor marker called CA 125.

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.

PARIS, Sept. 21 (Xinhua) -- European heavy-lift launcher Ariane 5 lifted off two communication satellites Wednesday from the Kourou launch centre in French Guiana, live broadcast of the launching process showed.The rocket, carrying the two communication satellites Arabsat 5C and SES-2, was launched at GMT 2138.This was the fifth heavy-lift mission of Ariane 5 in 2011. Arianespace had planned six Ariane 5 missions through 2011.The satellite Arabsat-5C was developed for the Arab Satellite Communications Organization (Arabsat) to provide satellite capacity in both C-band and Ka-band frequencies for a wide range of communications services.Jointly produced by Europe's EADS Astrium and Thales Alenia Space, it will be positioned at 20 degree East orbital location to cover the Middle East and Africa.Manufactured by Orbital Sciences Corporation of the United States, SES-2 will join the fleet of European satellite telecommunications operator SES, and is to be positioned at 87 degree West for coverage over North America and the Caribbean.Both Arabsat-5C and SES-2 have life-spans as long as 15 years.This Ariane 5 dual-passenger mission was postponed from Tuesday due to local strikes of French Guiana workers.Founded in 1980 as the world's first launch service and solutions company, Arianespace planned to achieve six Ariane 5 missions through 2011. Through 2010, heavy-lift workhorse Ariane 5 finished six missions, sending a dozen spacecraft into expected orbits.The next mission from Arianespace centre in Kourou was scheduled for Oct. 20 by medium-lift vehicle Soyuz. It will be Soyuz' first mission from French Guiana with a pair of satellites for Europe's Galileo satellite navigation system.

SAN FRANCISCO, June 14 (Xinhua) -- Google on Tuesday introduced several new features of its search services on desktops and smartphones, which the Internet search giant said could help users get to their search results faster.SEARCH BY VOICE, IMAGESpeaking at Google's Inside Search event in San Francisco, Mike Cohen, head of the company's speech technology efforts, said its voice search is now available in 27 languages and dialects, an estimated coverage of around 5 billion people or two-thirds of world population.Voice search has already been available in Google's mobile search application from 2008. Adding the feature to desktops is part of Google's strategy to bring mobile innovations to its desktop search.The voice search on desktop performs similarly to voice search on smartphones -- users can click the microphone button and speak the query. It is only available via Google's Chrome browser for now.Cohen noted that the volume of Google mobile speech inputs has increased by six times in the last year.Also at the event, Google introduced search-by-image, which enables users to drag-and-drop, copy-and-paste image URL, or upload the image from the desktop into the search box. They can also use a Chrome or FireFox software extension to add images to the search.Google said the search-by-image feature will be available in most countries and regions over the next few days to Chrome users, noting that it will not collect and store any images that users use.

BERLIN, June 17 (Xinhua) -- German authority said on Friday first case of human spreading deadly E. coli is detected, as death toll increases to 39 worldwide.A woman working in a kitchen of a catering company was infected by E. coli from sprouts, though she didn't fall ill immediately, said Harald Kehlborn, a spokesman for the consumer protection ministry of German state Hesse.Then she spread E. coli unconsciously to another 20 people through the food she prepared, said Kehlborn.The woman later developed serious complication of hemolytic- uremic syndrome (HUS), which causes failure of kidney and nervous system.According to the data of the Robert Koch Institute, Germany's national disease control centre, the number of people who are infected has reached 3,408 in Germany and 798 people have fallen into HUS, while the infection speed is slowing down.

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