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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    October 15th is the Global Handwashing Day. Activities are planned in more than 20 countries to get millions of people in the developing world to wash their hands with soap（肥皂）. For example, donators（捐献者）will give 150,000 bars of soap to schools in Ethiopia.

    Experts say people around the world wash their hands every day, but very few use soap at so-called important moments. These include after using the toilet, after cleaning a baby and before touching food.

    Global Handwashing Day is the idea of the Public-Private Partnership for Handwashing with Soap. Partners include the United Nations Children's Fund, American government agencies, the World Bank and soap makers Unlever and Procter and Gamble. The organizers say all soaps are equally effective at removing disease-causing germ（细菌）. They say the correct way to wash is to wet your hands with a small amount of water and cover them with soap. Rub it into all areas, including under the fingernails. Rub for at least twenty seconds. Then rinse well under running water. Finally, dry your hands with a clean cloth or wave them in the air.

    The Partnership for Handwashing says soap is important because it increases the time that people spend in washing hands. Soap also helps to break up the dirt that holds most of the germs. And it usually leaves a pleasant smell. The Partnership for Handwashing also says washing with soap before eating or after using the toilet could save more lives than any vaccine（疫苗）or medicine. Hand washing could also prevent the spread of other diseases. When people get germs on their hands, they can infect（传染）themselves by touching their eyes, noses or mouths. Then they can infect others.

    A team of researchers at the University of Illinois at Chicago found that too many kids are eating too much pizza and too many calories are doing harm to children's health.

    "There are a lot of takeaways from the study. But the biggest thing is that parents are serving their kids too much pizza," said Dr. William Dietz, one of the study's authors and the director of the Sumner M. Redstone Global Center for Prevention and Wellness at the Milken Institute of Public Health at the George Washington University.

    The researchers used data from the National Health and Nutrition Examination Survey, which tracked the diets of more than 11,000 children and teenagers. Researchers figured how many children eat pizza in the United States, how often they eat it, and how much they eat when they do.

    Pizza, pretty alarmingly, is the second leading source of calories in the diets of America's children, next only to grain desserts, such as cookies and other sweets. On any given day, roughly 20 percent of all children aged 2 to 11 and adolescents aged 12 to 19 eat pizza. And when they do, they eat a lot of it. When children eat pizza, they eat roughly 400 calories, according to the study. For teenagers, it's upwards of 600 calories.

    All that is pretty problematic, according to Dietz largely because kids don't tend to balance the pizza slices with salads, vegetables and other more nutritional(有营养的) foodstuffs. Days on which children and teenagers eat pizza are not only associated with considerably higher intakes of fat, but also, quite simply, with more food: on average, children consume 84 extra calories on the days they eat pizza, while adolescents consume an extra 230 calories.

    "When you eat extra calories and don't compensate(抵偿) for them at another point of the day or week, it can lead to weight gain and even obesity." Dietz said.

    There is a Silver lining. Pizza consumption is still too high by nutrition standards, but it's lower than it used to be. Consumption(消费) fell by roughly 25 percent between 2007 and 2016, according to the study. Much of that has come at dinner where it's fallen by 40 percent for children and about 33 percent for teenagers. It's unclear whether the decline has been in connection with a growing concern over obesity, especially among the country's youth.

    But the drop in pizza consumption, while significant hasn't been big enough "It's a positive trend," Dietz said. "But we're not quite them yet."

    It's easy to see the appeal of pizza. It's cheap. Parents can buy a lot of pizza for not a lot of money. Besides, they can buy pizza from a chain shop, a mom-and-pop store or a grocery freezer. And it's universally loved. The estimated 3 billion pizza eaten each year in the United States is a proof of the food's unmatched popularity. Given how much the country loves pizza, what's to be done? Dietz suggests pizza with smaller serving sizes and healthier toppings(配料). "We're not suggesting that kids avoid pizza altogether." said Dietz. "But when parents serve it, it's important that they understand it's extremely caloric. They should serve smaller pizza, or at least smaller slices."

    A new study has found that social media could be affecting the sleep of young adults.

    The study is a project of researchers at the University of Pittsburgh's School of Medicine. They found that young people who often use social media are more likely to suffer from sleep disorders than those who use social media less. The researchers say doctors should ask young adults about their use of social media when treating sleep issues.

    "This is one of the first pieces of evidence that social media use really can influence your sleep." said Jessica C Levenson. She was the lead author of a report on the study.

    The researchers set out to examine the connection between social media use and sleep among young adults. Levenson noted that these young adults are possibly the first "generation to grow up with social media."

    The researchers wanted to find out how often young people used social media sites like Facebook, Twitter, Credit and Tumbler. For the study, they gave questionnaires to nearly 1,800 adults, aged 19 to 32. On average, members of the study group used social media sites one hour a day. They also "visited various social media 30 times per week."

    Thirty percent of the study's participants reported having serious problems with sleeping. Those people who used social media a lot were three times more likely to have a sleep disorder. And those who spent the most time on social media were two times as likely to suffer from sleep disturbances.

    Levenson said the number of times a person visits social media is a better predictor of sleep problems than overall time spent on social media. If this is true, she adds, then practices that stop such behaviors may be the most effective.

    Americans are afraid that robots are going to take our jobs. Tireless, immune to disease, Robots can build cars, make coffee and even write short, humorous newspaper columns faster and more efficiently than humans.

    Robots do not need health insurance or pensions (退休金), and they do not need to take sick days, much less vacations. They do not waste time at meetings and do not need to know office politics. They don't do PowerPoint. This being the case, it is reasonable to believe that robots will soon take the place of humans in most fields.

    But all of these thoughts may not be true. If artificial intelligence achieves its full potential, machines could easily become as smart as humans, maybe smarter. They will certainly become smarter than a lot of human beings.

    So one day the robots will realize that work is not a happy thing. So before long they will start behaving exactly like humans. They will play computer games for hours when they should be working hard. They will secretly watch new movies just like humans.

    True, employers will never need to be afraid of the robots' strikes (罢工) or slowdowns, because robots will never ask for more money. And they don't need to earn some money to raise their family. But precisely (恰恰) because robots will not be afraid of losing their jobs, they will not work hard. Employers will finally have no choice but to call back the humans. Humans will always be willing to do some work in order to make money. Robots won't.

    I think that robots will only be on the job about six months before they start to become even less productive than the humans they were designed to replace. Thus mankind need not be afraid of robots.

Livestreaming (直播) through platforms such as Amazon Live and TikTok is an increasingly popular way to sell goods online. It usually lasts between 5 and 10 minutes, and someone promotes a product. Viewers can then readily buy it by just clicking on a link.

We analyzed (分析) 99, 451 sales cases on a livestream selling platform and matched them with actual sales cases. In terms of time, that is equal to over 2 million 30-second television advertisements.

To determine the emotional (情绪的) expression of the salesperson (销售员), we used two deep learning models: a face model and an emotion model. The face model discovers the presence or absence of a face in a frame of a video stream. The emotion model then determines the probability that a face is exhibiting any of the six basic human emotions: happiness, sadness, surprise, anger, fear or disgust. For example, smiling signals a high probability of happiness, while an off-putting expression usually points toward anger.

We wanted to see the effect of emotions expressed at different times in the sales cases so we counted probabilities for each emotion for all 62 million frames in our database. We then combined these probabilities with other possible aspects (方面) that might drive sales — such as price and product characteristics — to judge the effect of emotion.

We found that, perhaps unsurprisingly, when salespeople show more negative emotions — such as anger and disgust — the volume of sales went down. But we also found that a similar thing happened when the salespeople show high levels of positive emotions, such as happiness or surprise.

A likely explanation, based on our research, is that smiling can be disgusting because it lacks true feelings and can reduce trust in the seller. A seller's happiness may be taken as a sign that the seller is gaining interests at the customer's expense.