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LOS ANGELES, July 3 (Xinhua) -- Warming of the ocean's subsurface layers will melt underwater portions of the Greenland and Antarctic ice sheets faster than previously thought, increasing the sea level more than already projected, a new study suggests.The subsurface ocean layers surrounding the polar ice sheets will warm substantially as global warming progresses, according to the study led by researchers from the University of Arizona (UA).In addition to being exposed to warming air, underwater portions of the polar ice sheets and glaciers will be bathed in warming seawater, said the study appearing on the website of the American Association for the Advancement of Science (AAAS) on Sunday.The research, based on 19 state-of-the-art climate models, proposes a new mechanism by which global warming will accelerate the melting of the great ice sheets during this century and the next."To my knowledge, this study is the first to quantify and compare future ocean warming around the Greenland and the Antarctic ice sheets using an ensemble of models," said lead author Jianjun Yin, a UA assistant professor of geosciences.According to the study, the subsurface ocean along the Greenland coast could increase as much as 3.6 F (2 C) by 2100.Most previous research has focused on how increases in atmospheric temperatures would affect the ice sheets, he said."Ocean warming is very important compared to atmospheric warming because water has a much larger heat capacity than air," Yin said. "If you put an ice cube in a warm room, it will melt in several hours. But if you put an ice cube in a cup of warm water, it will disappear in just minutes."Given a mid-level increase in greenhouse gases, the researchers found the ocean layer about 650 to 1,650 feet (200 to 500 meters) below the surface would warm, on average, about 1.8 F (1 C) by 2100. Along the Greenland coast, that layer would warm twice as much, but along Antarctica would warm less, only 0.9 F (0.5 C)."No one has noticed this discrepancy before -- that the subsurface oceans surrounding Greenland and Antarctica warm very differently," Yin said.Part of the warming in the North comes from the Gulf Stream carrying warm subtropical waters north. By contrast, the Antarctic Circumpolar Current blocks some of the subtropical warmth from entering the Antarctic's coastal waters.Even so, the Antarctic ice sheet will be bathed in warming waters, according to the study.This paper adds to the evidence that sea level would rise by the end of this century by around one meter and a good deal more in succeeding centuries, the study noted.The study, "Different Magnitudes of Projected Subsurface Ocean Warming Around Greenland and Antarctica," is scheduled for the upcoming edition of Nature Geoscience later this month.

SAN FRANCISCO, Sept. 22 (Xinhua) -- Facebook on Thursday introduced Timeline, a new profile design featuring milestones of one's life on a single page.At Facebook's f8 developer conference, Chief Executive Officer Mark Zuckerberg promoted the new feature, a blog-like presentation that let users scrolls vertically through the big moments of one's life."It's how you can tell the whole story of your life in a single page," said Zuckerberg, showing his Timeline which started from a baby photo.Zuckerberg assured users that they have complete control over their Timeline, saying that they can decide what content will appear and who can see it. The new feature will be available in a few weeks.Half a billion people are using Facebook in the world everyday, according to Zuckerberg.

LOS ANGELES, July 18 (Xinhua) -- U.S. scientists have proven that oncogenes can change normal cells into stem-like cells, paving the way to a safer and more practical approach to treating diseases like multiple sclerosis and cancer with stem cell therapy.In a collaborative study, researchers from the Keck School of Medicine of the University of Southern California (USC), and the Children's Hospital of Orange County (CHOC) in California and Good Samaritan Hospital Medical Center in New York have successfully converted human skin cells into brain cells by suppressing the expression of p53, a protein encoded by a widely studied oncogene. This suggests that p53 mutation helps determine cell fate -- good or bad -- rather than only the outcome of cancer.Oncogenes are generally thought to be genes that, when mutated, change healthy cells into cancerous tumor cells.Study findings were appearing Monday on the website of the American Association for the Advancement of Science (AAAS)."The reality may be more complicated than people think," said Jiang F. Zhong, Ph.D., assistant professor of pathology at the Keck School. "What is a stem cell gene? What is a cancer gene? It may be the same thing.""When you turn off p53, people think the cell becomes cancerous because we tend to focus on the bad thing," Zhong said. "Actually, the cell becomes more plastic and could do good things, too. Let's say the cell is like a person who loses his job (the restriction of p53). He could become a criminal or he could find another job and have a positive effect on society. What pushes him one way or the other, we don't know because the environment is very complicated."Stem cells can divide and differentiate into different types of cells in the body. In humans, embryonic stem cells differentiate into three families, or germ layers, of cells. The reasons why and how certain stem cells differentiate into particular layers are not clearly understood. However, from those layers, tissues and organs develop. The endoderm, for example, leads to formation of the stomach, colon and lungs, while the mesoderm forms blood, bone and heart tissue. In its study, Zhong's team examined human skin cells, which are related to brain and neural cells from the ectoderm.When p53 was suppressed, the skin cells developed into cells that looked exactly like human embryonic stem cells. But, unlike other man-made stem cells that are "pluripotent" and can become any other cells in the body, these cells differentiated only into cells from the same germ layer, ectoderm."IPSCs (induced pluripotent stem cells) can turn into anything, so they are hard to control," Zhong said. "Our cells are staying within the ectoderm lineage."Zhong said he expects that suppressing other oncogenes in other families of cells would have the same effect, which could have critical significance for stem cell therapy. Future research should focus on determining which genes to manipulate, Zhong said.The study is slated to appear in the Proceedings of the National Academy of Sciences later this month, according to AAAS.

BEIJING, June 26 (Xinhua) -- China on Sunday issued a regulation on drug rehabilitation that encourages drug users to voluntarily undergo rehabilitation programs.The regulation took effect Sunday as a supplement of the country's anti-drug law that was implemented three years ago.Drug users who voluntarily receive intervention programs "will be exempt from punishment," said the regulation, promulgated on the 24th International Day Against Drug Abuse and Illicit Trafficking, which falls on Sunday.With seven chapters and 46 articles, it also stipulates the rights and obligations of drug addicts, as well as supporting measures for voluntary, community-based, and government-ordered drug rehabilitation.Up to date, more than two million Chinese have been receiving compulsive rehabilitation or treatment, statistics show. However, many of them find it difficult to completely give up the addiction.The regulation, aiming to explore effective ways to curb drug use, calls for boosting "the role of communities and families" in helping reduce drug users' dependency on narcotics.It asks rehabilitation centers to provide addicts with consulting services and education on the prevention of HIV/AIDS and other contagious diseases.Efforts should be made to "boost pharmaceutical management" so as to prevent loss or abuse of psychotropic substances and narcotics, the regulation says.The regulation also stipulates on the protection of drug addicts' personal information, saying "members of the police, judiciary and health departments who cause the leak of personal information must be punished."The regulation has solicited public comments before it was released.Transnational drug trafficking remains rampant in China, particularly in southwestern border regions of Yunnan and Guangxi.A report issued last month by China's National Narcotics Control Commission said authorities investigated 89,000 drug-related crimes and arrested 101,000 suspects last year.Law enforcers confiscated 5.3 metric tonnes of heroin and one metric tonne of opium in 2010, the report said, adding that intervention programs were used to treat and rehabilitate some 175,000 drug addicts last year.

WASHINGTON, July 18 (Xinhua) -- Exposure to secondhand smoke ( SHS) is associated with increased risk of hearing loss among adolescents, according to a report in the July issue of Archives of Otolaryngology -- Head and Neck Surgery.Among U.S. children, approximately 60 percent are exposed to SHS, according to background information in the article. Studies have associated exposure to secondhand smoke prenatally or during childhood with various health conditions, from low birth weight and respiratory infections to behavioral problems and otitis media. Children exposed to SHS are more likely to develop recurrent otitis media, the authors note. "Secondhand smoke may also have the potential to have an impact on auditory development, leading to sensorineural hearing loss (SNHL)," they add.Anil Lalwani and colleagues from New York University Langone Medical Center examined the risk factors for SNHL, including SHS, among adolescents, stratified by demographic groups. They included 1,533 individuals from 12 years to 19 years of age who participated in the National Health and Nutrition Examination Survey from 2005 to 2006.Participants were interviewed about their health status and family medical history, exposure to SHS, and self-recognition of hearing impairment. In addition, they underwent a physical examination, including blood testing for cotinine (a by-product of nicotine exposure), and hearing tests.Compared with teens who had no SHS exposure, those who were exposed to secondhand smoke exhibited higher rates of low- and high-frequency hearing loss. The rate of hearing loss appeared to be cumulative, increasing with the level of cotinine detected by blood tests. The results also demonstrated that more than 80 percent of participants with hearing loss did not realize they had impairment.As hearing loss early in life can cause problems with development and functioning, the authors suggest that these results have "significant implications for public health in the United States."They note that most adolescents do not receive screening for hearing loss in the absence of risk factors.If further studies replicate these results, they state, SHS could be considered one such risk factor.

来源：资阳报