A study published Monday found that people who sleep less tend to be fat，and experts said it's time to find out if more sleep will fight fatness.

    “We've put so much emphasis on diet and exercise that we've failed to recognize the value of good sleep，”said Fred Turek，a physician at Northwestern University.

    Monday's study from Eastern Virgnia Medical School in Norfolk covered 1,000 people and found that total sleep time decreased as body mass index－a measure of weight based on height increased.

    “Men slept an average of 27 minutes less than women and overweight and fat patients slept less than patients with normal weights，”it said.In general the fatter subjects slept about 1.8 hours a week less than those with normal weights.

    “Americans experience insufficient sleep and fat bodies.Clinicians are aware of the burden of fatness on patients，”the study said.

    “Our findings suggest that major extensions of sleep time may not be necessary，as an extra 20 minutes of sleep per night seems to be associated with a lower body mass index，”it added.

    “We caution that this study does not set up a cause­and­effect relationship between restricted sleep and fatness，but investigations indicating success in weight loss via extensions of sleep would help greatly to set up such a relationship.”

    The study was published in the Archives of Internal Medicine along with an editorial by Turek and Northwestern colleague Joseph Bass commenting on it and related research.

    In an interview，Turek said some studies have shown the lack of sleep causes declines in an appetiteholding back protein hormone，and increases in another hormone that cause a longing for food.“In addition neuropathies(神经疗法)in the brain governing sleep and fatness appear to overlap(部分重叠)，”he said.

    “Fatness has been rising dramatically in developed countries and reached epidemic(流行病)levels in the United States，”it added，“leading to a variety of health problems.”

    Life may have evolved on at least three planets within a newly discovered solar system 39 light years from Earth. Astronomers at the NASA have discovered no less than seven roughly Earth-sized worlds orbiting a dwarf star in the system. Scientists had previously identified a tiny number of "exoplanets", which are believed to have the qualities needed to support life. However, the new system contains an unprecedented(前所未有) number of Earth-sized, probably rocky planets, and is being acknowledged as an "accelerated leap forward" in the search for extraterrestrial (外星球的)life.

    Three of the new planets are said to be particularly promising because there might exist oceans. Thomas Zurbuchen, associate administrator of NASA, told a press conference in Washington: "This gives us a hint that finding a second Earth is not a matter of 'if', but 'when'."

    The planets were discovered using NASA's Spitzer Space Telescope, which was able to track how fast each of the planets crossed the star Trappist-l and completed an orbit. From this the research team calculated how far the planets were from their star, and therefore how likely they are to be habitable.

    NASA's Hubble Space Telescope is already being used to search for atmospheres around the planets. Future telescopes, including the proposed European Extremely Large Telescope and the James Webb Space Telescope, may be powerful enough to discover markers of life, such as oxygen in the atmospheres of exoplanets.

    Astronomers believe there could be as many as 40 billion potentially habitable worlds in our galaxy, the Milky Way. Prof Zurbuchen said that now was a "gold-rush phase" in the search for these exoplanets.

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    Today's post is almost about signs in English. You will see signs on the road while driving or when walking down a street. Now let's take a closer look at the signs in the picture below, so you can fully understand what they mean in case you come across one of them.

    Starting with the top row, we have a:

    Yield sign—This sign indicates (标示) that you need to slow down ,but you may not have to come to a full stop.

    Crosswalk—This is a sign that indicates people have the right of way to cross the street, so cars have to stop when they see a person waiting next to one of these signs.

    Second row:

    Do not enter—This sign indicates you are not allowed to enter a road at that point.

    Buckle up(系好安全带)!— There are often signs on roads in the United States reminding people that wearing seat belts(安全带) is mandatory (强制的) (seat belt laws differ depending on what state you are in ,but all US states have seat belt laws).

    Third row:

    Be alert (警惕的) for bears—This is another sign that is used to indicate to drivers and pedestrians (行人) that they should be alert for wildlife in the area.

Playground—This is the sign used to alert drivers that there is a playground nearby, so it is a good idea to slow down and watch for children.

    All of us know that smoking does harm to our health. But do you think everything will be OK as long as you quit smoking?

    Unfortunately, the answer is NO.

    New research has found that even if you give up smoking, the damage it has done to your genes (基因) will stay there for a much longer time. In the research, a team of US scientists studied the blood of 16,000 people. Among them, some were smokers, some used to smoke, and the rest were non-smokers. Scientists compared their genes and found that more than 7, 000 genes of smokers had changed—a number that is one-third of known human genes. According to NBC News, both heart disease and cancer are caused by genetic changes. Some people may have had the changes when they were born, but most people get them in their daily lives while doing things like smoking. When you stop smoking, a lot of these genes will return to normal within five years. This means your body is trying to heal (治愈) itself of the harmful effects of smoking. But the changes in some of the genes stay for longer. They can stay for as long as 30 years, It's almost like leaving a footprint on wet cement (水泥)—it will always be there, even when you've walked away and when the cement becomes dry. Although the study results may make people unhappy, there is a bright side: the findings could help scientists invent medicine to treat genetic damage caused by smoking or find ways to tell which people have heart disease or cancer risks.

    You might dream of fluency in this or that language, and maybe you have already achieved fluency in a foreign language. {#blank#}1{#/blank#}

    Fluency, like all abstract terms, has no universal meaning. Each individual must determine what the term means. {#blank#}2{#/blank#}

    Perfect fluency means knowing each word you encounter, speaking quickly, clearly and easily and having no accent. {#blank#}3{#/blank#} You aren't familiar with every word of your native language, and sometimes you have to search for the right word, even in your mother tongue.

    Quick fluency is the type of fluency you see in advertisements, because "Master a Language in 2 Months!" sounds very catchier than "Fluency in 20 Years!" {#blank#}4{#/blank#} It is possible to achieve quick fluency, but the fluency achieved after such a short time frame will be a very thin, superficial fluency.

    {#blank#}5{#/blank#} Native-like fluency means that you generally know all the same words that a native knows and can speak at the same pace with the same amount of ease as a native speaker. You will likely have an accent, but as long as your conversation partner can understand you, it doesn't matter.

    Literary fluency is like graduating from native-like to educated-native-like fluency. It focuses on the more intellectual side of a language: including in literature, attending university, composing song lyrics, etc.

    There are a ton of other things that fluency could potentially be, but that's up to you to figure out.

    Chinese high school students have the longest study hours compared to their peers (同龄人) in Japan, the US and the Republic of Korea, a survey conducted by the four countries said.

    The survey, released by the China Youth and Children Research Center (CYCRC) on Monday, was jointly conducted with institutions in the four countries in September—October of 2008. It covers nearly 4, 000 students in senior high schools and vocational high schools in the four countries.

    About 78.3 percent of Chinese students said they spend more than eight hours at school and 56.7 percent said they study at least two more hours each day at home. By contrast, only 24.7 percent of their peers in the US, 20.5 percent in Japan and 15.4 percent in Korea study more than two hours after school.

    Around 60 percent of all students surveyed said their burden for studies was the heaviest; however, the Japanese felt their burden was the worst with respondents (应答者) reaching 79.2 percent.

    Among the five biggest headaches for young people in the four countries were: over—scheduling ranked first, followed by a boring leisure life, unsatisfied appearance, little time for exercise and making friends, and no spare money.

    "Moderate (适度的) study pressure can better drive students to develop, however, too much will squeeze (挤) their development space, and can even cause harm to their physical and psychological health," the survey said.

    "Balancing their studies and all-round development is a very important task," it said.