中山大便黄色出血(中山痔疮流血了怎么办) (今日更新中)

WASHINGTON, Aug. 31 (Xinhua) -- Astronomers using NASA's Chandra X-ray Observatory discovered the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way, NASA announced Wednesday.Approximately 160 million light years from Earth, the pair is the nearest known such phenomenon.The black holes are located near the center of the spiral galaxy NGC 3393. Separated by only 490 light years, the black holes are likely the remnant of a merger of two galaxies of unequal mass a billion or more years ago.Both of the supermassive black holes are heavily obscured by dust and gas, which makes them difficult to observe in optical light. Because X-rays are more energetic, they can penetrate this obscuring material. Chandra's X-ray spectra show clear signatures of a pair of supermassive black holes."If this galaxy weren't so close, we'd have no chance of separating the two black holes the way we have," said Pepi Fabbiano of the Harvard-Smithsonian Center for Astrophysics, who led the study that appeared Wednesday in on-line issue of the journal Nature. "Since this galaxy was right under our noses by cosmic standards, it makes us wonder how many of these black hole pairs we've been missing."Previous observations in X-rays and at other wavelengths indicated that a single supermassive black hole existed in the center of NGC 3393. However, a long look by Chandra allowed the researchers to detect and separate the dual black holes. Both black holes are actively growing and emitting X-rays as gas falls towards them and becomes hotter.When two equal-sized spiral galaxies merge, astronomers think it should result in the formation of a black hole pair and a galaxy with a disrupted appearance and intense star formation. A well-known example is the pair of supermassive black holes in NGC 6240, which is located about 330 million light years from Earth.However, NGC 3393 is a well-organized spiral galaxy, and its central bulge is dominated by old stars. These are unusual properties for a galaxy containing a pair of black holes.

CANBERRA, Sept. 9 (Xinhua) -- Managing other people at work triggers structural changes in the brain, protecting its memory and learning center well into old age, Australia's study revealed on Friday.Australia's University of New South Wales (UNSW) researchers have, for the first time, identified a clear link between managerial experience throughout a person's working life, and the integrity and larger size of an individual's hippocampus (the area of the brain responsible for learning and memory) at the age of 80. "We found a clear relationship between the number of employees a person may have supervised or been responsible for and the size of the hippocampus," Dr Michael Valenzuela, Leader of Regenerative Neuroscience in UNSW's School of Psychiatry, said in a statement released on Friday."This could be linked to the unique mental demands of managing people, which requires continuous problem solving, short term memory and a lot of emotional intelligence, such as the ability to put yourself in another person's shoes. Over time this could translate into the structural brain changes we observed."The findings confirmed that staying mentally active promotes brain health, potentially warding off neurodegenerative diseases such as Alzheimer's.Using MRI imagery in a cohort of 75-92 year-olds, researchers found larger hippocampal volumes in those with managerial experience compared to those without. The effect was also seen in women who had taken on managerial roles in nursing or teaching, for example.The study was presented at this week's Brain Sciences UNSW symposium Brain Plasticity The Adaptable Brain, held in Australia.

BEIJING, Sept. 20 (Xinhua) -- Floods and landslides triggered by recent heavy rains in eight of China's provincial-level regions have left 70 people dead and 32 others missing this month.Heavy downpours, floods and other related disasters have affected Sichuan, Shaanxi, Henan, Chongqing, Hubei, Shandong, Shanxi and Gansu, the National Disaster Reduction Commission said in a statement released on Tuesday.As of Tuesday, these disasters have affected 21.56 million people and caused an estimated 26.09 billion yuan (4.08 billion U.S. dollars) in direct economic losses, the statement said.

BERLIN, Aug. 28 (Xinhua) -- Mercedes-Benz, the world leading luxury car producer, celebrates the 125th anniversary of its invention of automobile with what it claimed the largest gathering ever, at the former Tempelhof airport in Berlin on the weekend.The Mercedes-Benz Club and Mercedes-Benz enthusiasts greet visitors with some 1,800 well-assorted Mercedes-Benz-branded vehicles, ranging from vintage and classic passenger cars to a variety of historic commercial vehicles, on a vast open areas of 250,000 square metres of the abandoned Tempelhof airport, which was closed in 2008.It took Mr. Lauritzen and his wife two days' drive of their cherised wecker of Mercedes-Benz Cabriolet B. 320.W 142.-3,4l to reach here for taking part in the pageant."It is a long journey, but we are happy to be here to see more class cars and more friends with same interests," Mrs Lauritzen said.Owners take the opportunity to present their lovingly cared-for vehicles, which include a number of truly rare items of automotive history, to the Berlin public.The couple of Mr. Kerner drove their red Mercedes-Benz 170Dba, a made-in-1952 model with a range of special and unique designs which are very rarely seen now, over journey of 155 km from Bitterfeld to join in the gala."I'm fond of driving my classic car of Benz," said Mrs Kerner, despite it can run maximally at a speed of 50 to 80 km per hour, "but I truly enjoy the diesel engine sounds and the historic feeling it evokes."The legendary Silver Arrows, dating from the 1930s and 1950s, are also presented from the Mercedes-Benz Classic collection for demonstration drives."The brilliant history of the Silver Arrows will be brought to life with a demonstration of their impressive engine sound and incredible driving dynamics," said Michael Bock, head of Mercedes-Benz Classic and Director of Mercedes-Benz Museum GmbH."It is not often that these racing cars are driven in public, so this will be a true highlight of the program of events in Tempelhof."During the grand show, visitors are also accessible to first-hand experiences of the latest technologies applicable in the future for in passenger cars, commercial vehicles and racing cars."Some 125 years ago, Carl Benz submitted his patent application for the Benz Patent Motor Car to the Patent Office in Berlin", the organizer appealed to the visitors, saying now Mercedes-Benz is returning to Berlin to celebrate together with Berliners.

BEIJING, July 22 (Xinhuanet) -- Regulation is needed to govern rapidly expanding research in animals containing human tissue or genes, according to the Britain's Academy of Medical Sciences.Using animals with limited humanized traits is not new. Genetically engineered mice containing human DNA are already a mainstay of research into new drugs for diseases like cancer.For instance, Chinese scientists have already introduced human stem cells into goat fetuses and U.S. researchers have studied the idea of creating a mouse with human brain cells.But Martin Bobrow, a professor of medical genetics at the University of Cambridge, who led the Academy's working group, said there were three areas of particular concern."Where people begin to worry is when you get to the brain, to the germ cells, and to the sort of central features that help us recognize what is a person, like skin texture, facial shape and speech," he said.His report recommends that government should put in place a national expert body, working within the existing system for regulating animal research, to oversee such sensitive areas.British ministers said they welcomed the report and would consider its recommendations carefully.

来源：资阳报