徐州怀孕30周做四维彩超(徐州哪家医院四维彩超照的好) (今日更新中)

Robots perform a dance in a competition in Mudanjiang, northeast China's Heilongjiang Province, July 24, 2011. A nationwide robot competition was kicked off in the city on Sunday, with participants from 50 colleges and universities

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.

SAN FRANCISCO, June 6 (Xinhua) -- Apple's chief executive officer Steve Jobs on Monday took a break from his medical leave to introduce the company's new cloud-based service iCloud.Jobs, in his trademark black turtleneck and jeans, got a standing ovation in San Francisco's Moscone Center when he appeared on stage. Someone screamed "I love you," and Jobs said " it always helps and I appreciated it.""ICloud stores your content in the cloud and wirelessly pushes it to all your devices," said Jobs, calling it Apple's "next big insight."According to Apple, iCloud Backup will automatically back up users' iOS devices to iCloud daily over Wi-Fi when they charge their iPhone, iPad or iPod touch. Backup content includes purchased music, apps, camera roll, device settings and app data. It will also automatically upload documents from iWork in the cloud and pushes them to users' all relevant devices.The service will currently be free and replaces the former MobileMe which Apple once charged 99 U.S. dollars per year.Users will get five gigabytes of memory which is not counting purchased apps, music or books. A beta version is available on Monday and the final version will be shipping with iOS 5 this fall, with paid plans for more storage to be announced at that time.For a 24.99-dollar paid music plan named iTunes Match, a user's iTunes library will be scanned and they will gain instant access to those tracks or albums from compatible devices, rather than uploading them. Song files, including those converted from CDs, will also be uploaded to iCloud if they are not matched in iTunes stores but recognized by music labels.Jobs pointed out that iTunes Match paid plan is cheaper than Amazon's offering and Google has not announced a price yet, saying "it's an industry leading effort."The Apple CEO finally showed a photo of the company's new, massive data center in North Carolina to emphasize Apple is ready for iCloud service.Before Jobs, Apple executives introduced Lion, the eighth major release of Mac OS X and iOS 5, the next version of Apple's mobile operating system.Phil Schiller, Apple's marketing chief and Craig Federighi, the OS X software vice president, introduced ten key new features among the 250 ones of the new Mac operating system, including multi-touch features that bring the users experience on iPhone to their computers.Lion will be available to customers in July in Mac App Store. The price is adjusted to 29.99 dollars from 129 dollars Apple used to charge for upgrades.Scott Forstall, head of Apple's iOS software, demoed Apple's new mobile operating system, noting that iOS already has 44 percent of the mobile operating system market.The new version iOS 5 will have more than 200 new features, including a Notification Center that catches missed calls, mail messages and phone messages; and a feature called Reminder that provides virtual Post-it notes using geolocation technology.The new mobile operating system also integrates Twitter with many other iPhone apps and has a Newsstand on which the newspaper and magazines icons will be the actual covers of the publications.Apple said that iOS 5 is coming to the public this fall, which probably means the new iPhone is coming in the fall as well.Apple's new services are unveiled at its annual Worldwide Developers Conference (WWDC). Jobs kicked off the keynote event by saying that Apple had sold out 5,200 tickets to attendees just in two hours.

WASHINGTON, Sept. 12 (Xinhua) -- An enzyme that appears to play a role in controlling the brain's response to nicotine and alcohol in mice might be a promising target for a drug that simultaneously would treat nicotine addiction and alcohol abuse in people, U.S. researchers find.Over the course of four weeks, mice genetically engineered to lack the gene for protein kinase C (PKC) epsilon consumed less of a nicotine-containing water solution than normal mice, and were less likely to return to a chamber in which they had been given nicotine. In contrast, normal mice steadily increased their consumption of nicotine solution while the mice lacking PKC epsilon did not.The study conducted by researchers at the Ernest Gallo Clinic and Research Center, affiliated with the University of California, San Francisco, appeared Monday in the online edition of the Proceedings of the National Academy of Sciences.In normal mice, as in humans, nicotine binds to a certain class of nicotinic receptors located on dopamine neurons, which causes dopamine to be released in the brain. Dopamine creates a feeling of enjoyment, and thus prompts a sense of reward. Researchers found that mice lacking PKC epsilon are deficient in these nicotinic receptors.The finding complements earlier research in which researchers found that mice genetically engineered to lack the PKC epsilon enzyme drank less alcohol than normal mice and were disinclined to return to a chamber in which they had been given alcohol."This could mean that these mice might not get the same sense of reward from nicotine or alcohol," said Gallo senior associate director and investigator Robert Messing. "The enzyme looks like it regulates the part of the reward system that involves these nicotinic receptors."The reward system is a complex of areas in the brain that affect craving for nicotine, alcohol and other addictive substances.The next step in the research, said Messing, would be to develop compounds that inhibit PKC epsilon. The ultimate goal, he added, would be medications that could be used "to take the edge off of addiction by helping people get over some of their reward craving."

CHENGDU, Sept. 3 (Xinhua) -- A list of this year's top 500 Chinese enterprises was unveiled in the city of Chengdu in southwest China's Sichuan Province on Saturday.The Sinopec Group was ranked first, with last year's revenues reaching 1.97 trillion yuan (307.81 billion U.S. dollars), followed by the China National Petroleum Corp. and State Grid Corp., whose revenues hit 1.72 trillion yuan and 1.53 trillion yuan last year, respectively.The rest of the top 10 was rounded out by the Industrial and Commercial Bank of China, China Mobile, China Railway Group, China Railway Construction Corp., China Construction Bank, China Life Insurance Co. and Agricultural Bank of China.The list is the 10th of its kind to be jointly released by the China Enterprise Confederation and the China Enterprise Directors Association. The threshold for entering the list was raised to 14.2 billion yuan in revenues, an increase over the 11.08-billion-yuan threshold used during the previous year.Revenues for China's top 500 companies rose 31.6 percent year-on-year to 36.31 trillion yuan in 2010, while their total assets increased by 18.4 percent to 108.1 trillion yuan, the two organizations said.The companies reported profits of 2.08 trillion yuan for last year, a rise of 38.67 percent from one year earlier.They paid 2.73 trillion yuan in taxes in 2010, accounting for 37.3 percent of the country's total tax revenues.

来源：资阳报