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WASHINGTON, July 20 (Xinhua) -- Using the Hubble Space Telescope, astronomers have discovered a fourth moon orbiting the icy dwarf planet Pluto, the U.S. National Aeronautics and Space Administration (NASA) announced Wednesday in a statement. The tiny, new satellite, temporarily designated P4, was uncovered in a Hubble survey searching for rings around the dwarf planet.P4 was first seen in a photo taken with Hubble's Wide Field Camera 3 on June 28. It was confirmed in subsequent Hubble pictures taken on July 3 and July 18. It is the smallest moon discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter (32 to 113 km).Two labeled images of the Pluto system taken by the Hubble Space Telescope's Wide Field Camera 3 ultraviolet visible instrument with newly discovered fourth moon P4 circled. The image on the left was taken on June 28, 2011. The image of the right was taken on July 3, 2011."I find it remarkable that Hubble's cameras enabled us to see such a tiny object so clearly from a distance of more than 3 billion miles (5 billion km)," said Mark Showalter of the SETI Institute in California, who led this observing program with Hubble.P4 is located between the orbits of Nix and Hydra, which Hubble discovered in 2005. Charon was discovered in 1978 at the U.S. Naval Observatory and first resolved using Hubble in 1990 as a separate body from Pluto.The dwarf planet's entire moon system is believed to have formed by a collision between Pluto and another planet-sized body early in the history of the solar system. The smashup flung material that coalesced into the family of satellites observed around Pluto.The finding is a result of ongoing work to support NASA's New Horizons mission, scheduled to fly through the Pluto system in 2015. The mission is designed to provide new insights about worlds at the edge of our solar system. Hubble's mapping of Pluto's surface and discovery of its satellites have been invaluable to planning for New Horizons' close encounter."This is a fantastic discovery," said New Horizons' principal investigator Alan Stern of the Southwest Research Institute in Colorado. "Now that we know there's another moon in the Pluto system, we can plan close-up observations of it during our flyby."

Beijing, Sept. 13 (Xinhuanet) -- A fear of taking antidepressants often results in people's reluctance of going to see the doctor when they are suffering from depression, a study find.The finding was published Monday in the U.S. journal Annals of Family Medicine.The researchers from the University of California investigated 1,054 adults on why they wouldn't tell the doctors about their depression symptoms, as well as any possible mental disorder.Among the participants, 43 percent admitted that they had been reluctant to tell the doctor about their depression symptoms.Their top concern was the possibility of being prescribed an antidepressant -- a worry voiced by 23 percent of the whole study group.Another 16 percent thought dealing with "emotional issues" is not the doctor's job. And a similar percentage worried that the diagnosis of depression may leave a negative record on their medical records.The study would be helpful for looking into the reasons that patients harbor the attitudes that they do, said Dr. Hellerstein of the New York State Psychiatric Institute and Columbia University Medical Center in New York.

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."

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

KATHMANDU, Aug. 7 (Xinhua) -- Ban on smoking in public places will be enforced from Sunday with the Tobacco Control and Regulatory Act-2010 coming into effect.Those smoking in public places will be fined and civil servants will be liable to departmental action.Government offices, corporations, educational institutions, libraries, airports, public vehicles, orphanages, childcare centres, cinema halls, homes for the elderly, cultural centres, children's gardens, hotels, restaurants, resorts, girls' and boys' hostels, department stores, religious sites and industries have been designated no-smoking zones.Health Secretary Sudha Sharma said mass awareness campaign highlighting punishment will be carried out. She also said an inter-ministerial coordinating committee has been formed to enforce the law to ensure people's right to health. Pasting no- smoking notices at every public place will be mandatory.According to The Himalayan Times daily, the ban covers sale of tobacco products and single sticks within a 100-meter radius of educational and health institutions, children's homes, child care centers and home for elders.Anyone selling tobacco products to persons under the age of 18 years and pregnant women will be fined.The Act also prohibits advertising and sponsoring programs in the name of tobacco-related products through media. Offenders will be fined.The government's mass awareness campaign will cover the entire country to ensure effective implementation of the Act.

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