梅州怀孕几天能打胎(梅州要多久才能做打胎) (今日更新中)

BEIJING, May 20 (Xinhuanet) -- Scientists have discovered a Jupiter-sized exoplanet that is completely unbound from a host star, according the scientific journal "Nature" published Thursday.The research was conducted by astrophysicists from Osaka University in Japan.Using the technique called "gravitational microlensing", scientists turned their telescopes towards the centre of the Milky Way and detected this "lonely planet" moving in a extremely large orbit, which suggested it does not connect to any solar system.Then they estimated the total number of such wondering planets could be as many as 400 billion, based on the detection efficiency. This number far outnumbers the main-sequence stars such as our Sun."This is an amazing result, and if it is right, the implications for planet formation are profound," says astronomer Debra Fischer at Yale University in New Haven, Connecticut.And scientist began to consider the possibility that liquid water could exist on this kind of unbound planets. "That might be an attractive possibility for life," said David Stevenson, a planetary scientist at the California Institute of Technology.

You can think of NASA's Discovery program as a sort of outer-space American Idol: every few years the agency invites scientists to propose unmanned planetary missions. The projects have to address some sort of fundamental science question, and (this is the tough part) they have to be relatively cheap to pull off — say, half a billion dollars or so. Then the proposals go through a grueling competition before judges who aren't as nasty as Simon Cowell but who are every bit as tough. The one left standing at the end gets the equivalent of a recording contract: NASA supplies the funding and the launch vehicle, and away the winner goes — to orbit Mercury, as the Messenger spacecraft is doing right now; or to rendezvous with a couple of asteroids, as the Dawn mission will start doing this July; or to smash into a comet on purpose, a feat achieved by Deep Impact in 2005, a mission not to be confused with the movie of the same name. Now it's time for the next contenders. NASA has just announced that the first round of the latest Discovery competition is over, with three entries out of 28 moving on to the finals. They are, in increasing distance from Earth: the Geophysical Monitoring Station (GEMS) lander, which would use seismometers to study the interior of Mars; the Comet Hopper, which would do just that, leaping from place to place across the surface of Comet 46P/Wirtanen to see how different parts of the tumbling body react to heating by the sun; and the Titan Mare Explorer (TiME), which would plop into a sea of liquid hydrocarbons on Saturn's moon Titan — the first oceangoing vessel ever to set sail on another world. If you had to come up with a theme that ties all three missions together, it would be "origins." The Titan explorer, for example, will be studying a place that — in a crude way, at least — resembles the early planet Earth at a time when life arose here. Titan, with a thick atmosphere and a bizarro-world form of weather featuring toxic winds and hydrocarbon rain, is home to a mix of complex chemistry, complete with organic molecules. The oceans provide a medium in which the molecules can move around and interact with each other. It's even conceivable, though clearly a long shot, that some form of microscopic life already exists on this frigid moon. The Mars lander, by contrast, would visit a place where the seas — plain water in this case — vanished long ago. But the mission of GEMS goes far deeper than that. By analyzing Marsquakes on the Red Planet, GEMS will try to get a handle on what the interior of Mars is like. Scientists don't currently know whether the planet's core is liquid, like Earth's, or solid, or some mushy consistency in between. It all depends on how efficiently Mars has cooled since it formed 4.5 billion years ago, and that depends in turn on the planet's internal structure. "That's the mission," says Bruce Banerdt, of NASA's Jet Propulsion Laboratory, the lead scientist for GEMS. "We want to understand how Mars was built." Along with sensitive seismographic equipment, GEMS will drill down about 20 ft. (6 m) with a thermometer-equipped probe, trying to figure out how quickly the temperature rises with depth. "That will let us extrapolate all the way down to the center," Banerdt says, "which will tell us how fast Mars is cooling."

BEIJING, May 19 (Xinhuanet) -- LinkedIn said Wednesday that its stock will debut at 45 U.S. dollars per share, a higher price than the company was expecting even earlier this week, media reports said.The first major U.S. social networking firm to go public, LinkedIn jacked up its initial public offering (IPO) share price for 7.84 million shares to 45 dollars just a week after it first set a target of 32-35 dollars per share.It minted LinkedIn with a market value of more than 4 billion dollars, the highest for a U.S. Internet company taking its first bow on Wall Street since Google Inc. went public nearly seven years ago.The sale could bring in more than 354 million dollars. The company's shares are expected to begin trading on the New York Stock Exchange on Thursday under the symbol "LNKD".LinkedIn has more than 100 million members in over 200 countries and territories. In 2010, the company made 15 million dollars in profit on 243 million dollars in revenue, according to its SEC filing.LinkedIn's biggest shareholder is its founder and chairman, Reid Hoffman, who owns more than 21 percent of the company.

WASHINGTON, April 29 (Xinhua) -- A U.S. appeals court ruled on Friday that the Obama administration can continue the taxpayer- funding for human embryonic stem cell research.The U.S. Court of Appeals in Washington overturned a preliminary federal court order that would have blocked the U.S. Health and Human Services Department and the National Institutes of Health (NIH) from spending government money on embryonic stem cells research."Today's ruling is a victory for our scientists and patients around the world who stand to benefit from the groundbreaking medical research they're pursuing," said Nicholas Papas, a White House spokesman.U.S. President Barack Obama has been trying to expand government funding for human embryonic stem cells research, saying that years of progress on finding cures for spinal cord injuries, Parkinson's disease and other diseases would be lost without the government support on this field.Opponents have been arguing the research is unacceptable because embryonic stem cells can only be obtained through destroying human embryos.Last August, a federal judge ruled that the government-backed embryonic stem cell research violated the law because embryos were destroyed in the process and it jeopardized the position of researchers using adult stem cells for winning federal grants.The government immediately appealed to the ruling, and the appeals court said the research could continue at the NIH before the judge ruled on the case.

WASHINGTON, April 4 (Xinhua) -- Scientists have identified a gene that appears to play a role in regulating how much alcohol people drink, in a study of over 47,000 people published Monday in the Proceedings of the National Academy of Sciences.The researchers say that finding a common genetic variation influencing levels of alcohol consumption may lead to a better understanding of mechanisms underlying alcohol drinking behavior in the general population.The gene, called "autism susceptibility candidate 2", or AUTS2, has previously been linked to autism and attention deficit hyperactivity disorder, but its function is not known.The new study, by an international consortium led by scientists at Imperial College London and King's College London, found that there are two versions of the AUTS2 gene, one three times more common than the other. People with the less common version drink on average five percent less alcohol than people with the more common version.The gene is most active in parts of the brain associated with neuropsychological reward mechanisms, suggesting that it might play a part in regulating the positive reinforcement that people feel when they drink alcohol.Alcohol consumption is known to be partly determined by genes but until now the only gene known to make a notable contribution was the gene encoding alcohol dehydrogenase, an enzyme that breaks down alcohol in the liver.Professor Paul Elliott, from the School of Public Health at Imperial College London, said: "Of course there are a lot of factors that affect how much alcohol a person drinks, but we know from twin studies that genes play an important role. The difference that this particular gene makes is only small, but by finding it we've opened up a new area of research into the biological mechanisms that control drinking."

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