A new study suggests that the more teenagers watch television, the more likely they are to develop depression (忧郁) as young adults.

    The researchers used a national long-term survey of adolescent health to survey the relationship between media (媒体) use and depression. They based their findings on more than 4,000 adolescents who were not depressed when the survey began.

    As part of the survey, the young people were asked how many hours of television or videos they watched daily. They were also asked how often they played computer games and listened to the radio. Media use totaled an average of five and one-half hours a day. More than two hours of that was spent watching TV.

    Seven years later, more than seven percent of the young people had signs of depression. The average age at that time was twenty-one. The researchers say they did not find any such relationship with the use of other media such as movies, video games or radio, etc. But the study did find that every extra hour of television meant an eight percent increase in the chances of developing signs of depression. Young men were more likely than young women to develop depression given the same amount of media use.

    Last December, a popular magazine published a study of activities that help lead to happy lives. Researchers from the University of Maryland found that people who describe themselves as happy spend less time watching television than unhappy people. The study found that happy people are more likely to be socially active, to join in outdoor activities and to hang out with friends.

    If you are a teacher, join Youngzine and sign up your class for free today! Youngzine is an online News Magazine for school age children. It provides an educational, entertaining, yet safe way for kids and adults to get the latest news from around the world.

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    A serious problem for today's society is who should be responsible for our elderly and how to improve their lives. It is not only a financial problem but also a question of the system we want for our society. I would like to suggest several possible solutions to this problem.

    First, employers should take the responsibility for their retired employees. To make this possible, a percentage of profits should be set aside for this purpose. But when a company must take life-long responsibility for its employees, it may suffer from a commercial disadvantage due to higher employee costs.

    Another way of solving the problem is to return the responsibility to the individual. This means each person must save during his working years to pay for his years of retirement. This does not seem a very fair model since some people have enough trouble paying for their daily life without trying to earn extra to cover their retirement years. This means the government might have to step in to care for the poor.

    In addition, the government could take responsibility for the care of the elderly. This could be financed through government taxes to increase the level of pensions. Furthermore, some institutions should be created for senior citizens, which can help provide a comfortable life for them. Unfortunately, as the present situation in our country shows, this is not a truly viable answer. The government can seldom afford to care for the elderly, particularly when it is busy trying to care for the young.

    One further solution is that the government or social organizations establish some working places especially for the elderly where they are independent.

    To sum up, all these options have advantages and disadvantages. Therefore, it is reasonable to expect that some combination of these options may be needed to provide the care we hope to give to our elderly generations.

    Exercise is known to benefit people's mental health, but scientists recently discovered that too much exercise may have a negative effect on it.

    The researchers studied about 1.2 million people in the United States in 2013, 2015 and 2017. The participants, on average, experienced 3, 4 days of poor mental health each month. Those who did exercise experienced 1, 5 fewer days of poor mental health per month, compared to those who didn't exercise at all. The team found that people who exercised for 30 to 60 minutes three to five times a week had the best mental health, but those who exercised for more than three hours had worse mental health than those who didn't exercise at all.

    The scientists think that people who exercise so much may experience poorer mental health because that much exercise can be a sign of obsessive (强迫症患者) behaviors that have been associated with poor emotional and psychological outcomes. However, the only mental health disorder that the researchers looked at was depression.

    Among those who had been diagnosed with depression, people who did exercise experienced 3.75 fewer negative mental health days than those who did not, showing an ever greater difference, According to the Centers for Disease Control and Prevention. 7, 6 percent of people in the U.S. age 12 and over have depression. While all types of exercise appeared to help with mental health, cycling, gym-based exercise and team sports were the most beneficial.

    The team also looked at more specific factors, like education. People with a college education reported 17.8 percent fewer days of poor mental health than those without that level education Additionally, people in a healthy BMI (体重指数) range reported a 4 percent reduction in poor mental health days thin those whose BMIs were high. Even salary was a factor: compared to people with bower salaries, those with higher salaries experienced a 17 percent reduction in poor mental health days.

    The study showed that exercise can help with mental health, but that in some cases, limiting it may be necessary.

    It's really true what people say about English politeness: it's everywhere. When squeezing past someone in a narrow aisle, people say "sorry". When getting off a bus, English passengers say "thank you" rather than the driver. In Germany, people would never dream of doing these things. After all, squeezing past others is sometimes inevitable, and the bus driver is merely doing his job. I used to think the same way, without questioning it, until I started travelling to the British Isles and came to appreciate some more polite ways of interacting with people.

    People thank each other everywhere in England, all the time. When people buy something in a shop, customer and shop assistant in most cases thank each other twice or more. In Germany, it would be unusual to hear more than one thank you in such a conversation. British students thank their lecturers when leaving the room. English employers thank their employees for doing their jobs, as opposed to Germans.

    Another thing I observed during my stay was that English people rarely criticize others. Even when I was working and mistakes were pointed out to me, my employers emphasized several times but none of their explanations were intended as criticism. It has been my impression that by avoiding criticism, English people are making an effort to make others feel comfortable. This also is showed in other ways. British men still open doors for women, and British men are more likely to treat women to a meal than German men.

    When a laptop or smartphone battery starts losing its power, the only options are to buy an expensive replacement, or just keep it plugged in all the time. But a woman Mya Le Thai may have found the answer to this problem.

    Thai was frustrated that the batteries for her wireless devices degraded(降级)over time, until they failed to charge fully. She did not like having to keep her laptop connected to an electrical outlet to keep it powered on. So, she decided to do something about that problem. At first, she and her team at UC Irvine thought about inventing a new battery. But as they experimented, Thai discovered something that might permit lithium—ion(锂离子)batteries to last forever.

    Lithium-ion batteries power most wireless devices. Over time, the batteries lose the ability to hold a charge. Most of these batteries have a life span of about 7,000 charging cycles before they die. One of the reasons lithium—ion batteries degrade is their use of nanowires to carry electricity. Nanowires are extremely thin. A human hair is thousands of times thicker, for example. Nanowires are extremely efficient carriers of electricity, which makes them useful in batteries.

    But, Thai had a theory—the nanowires might last longer if covered with a gel(凝胶). She and her team tested this theory. "It was a long process and a lot of work, "Thai said. The team tried many coverings for the wires. PMMA, a type of plastic, was one of them. The nanowires were coated with PMMA and cycled through charges 200, 000 times. The PMMA-coated nanowires showed no evidence of damage. The results suggest that batteries could last forever, without losing charging ability.

    Thai hopes to continue her research to understand why this gel works so well and to see if any other gel could create better results and she is enjoying the publicity about her discovery. She said she never expected her research to get media coverage. "It's kind of cool," she said. "I'm really glad people are showing interest in my work and not just in the work itself, but also in technology and energy."