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.

    Are you carrying too much on your back at your back at school? I'm sure lots of children of your age will say “Yes”. Not only the students in China have this problem, but children in the United States also have heavy school bags.

    Doctors are starting to worry that younger and younger students are having back and neck problems as a result of school bags being too heavy for them.

    “It's hard for me to go upstairs with my bag because it's so heavy,” said Rick Hammond, an 11-year-old student in the US.

    Rick is among students who have common school bags with two straps（带子）to carry them, but many other students choose rolling（有滚轮的）bags.

    But even with rolling bags, getting up stairs and buses is still a problem for children. Many of them have hurt their backs and necks because of the heavy school bags.

    But how much is too much? Doctors say students should carry no more than 10% to 15% of their own body weight.

    Scout Batch, a back doctor, said children under Grade 4 should stay with 10%. But it is also important that older children don't stay with over 15%, because their bodies are still growing.

    “Children are losing their balance and falling down with their school bags,” he said.

    Parents and teachers are starting to tell children to only take home library books they will be reading that night. Some teachers are using pieces of paper or thin workbooks for students to take home.

    One of the best answers is, as some children said, to have no homework at all!

A popular saying goes, “Sticks and stones may break my bones, but words will never hurt me.” However, that's not really true. Words have the power to build us up or tear us down. It doesn't matter if the words come from someone else or ourselves — the positive and negative effects are just as lasting.

    We all talk to ourselves sometimes. We're usually too embarrassed to admit it, though. In fact, we really shouldn't be because more and more experts believe talking to ourselves out loud is a healthy habit.

    This “self-talk” helps us motivate ourselves, remember things, solve problems, and calm ourselves down. Be aware, though, that as much as 77% of self-talk tends to be negative. So in order to stay positive, we should only speak words of encouragement to ourselves. We should also be quick to give ourselves a pat on the back. The next time you finish a project, do well in a test, or finally clean your room, join me in saying “Good job!”

    Often, words come out of our mouths without us thinking about the effect they will have. But we should be aware that our words cause certain responses in others. For example, when returning an item to a store, we might use warm, friendly language during the exchange. And the clerk will probably respond in a similar manner. Or harsh（刻薄的）and critical language will most likely cause the clerk to be defensive.

    Words possess power because of their lasting effect. Many of us regret something we once said. And we remember unkind words said to us! Before speaking, we should always ask ourselves: Is it loving? Is it needed? If what we want to say doesn't pass this test, then it's better left unsaid.

    Words possess power: both positive and negative. Those around us receive encouragement when we speak positively. We can offer hope, build self-esteem（自尊）and motivate others to do their best. Negative words destroy all those things. Will we use our words to hurt or to heal? The choice is ours.

    Charlie is a teacher and his wife, Maria is an artist. The night before last, just before the longest day of the year, Charlie was sitting in a deckchair enjoying the warm summer air when Maria touched his shoulder and he could tell immediately she was a little worried about something. He asked her what the matter was and she replied that there was a strange thing on the jacket that was hanging in the bedroom. They had both lived in the West Indies (西印度群岛) and had seen a lot of strange creatures in their house before. But now they were living in England and so Charlie just laughed and said he would have a look at the "thing".

    He walked to the bedroom. He saw a jacket hanging in the bedroom and went up to it to have a closer look at the "thing". The moment he touched it, the thing sprang into life. Now Charlie experiences fear like the rest of us but when this creature opened its wings, he jumped out of his skin and ran screaming from the room like a small child doing about 100 miles an hour.

    For a moment the next-door neighbours thought that Charlie was murdering his wife because of the noise they could hear. In fact, it was a bat that frightened Charlie.

    Eventually Charlie managed to trap the bat in a box and took it to the garden to let the bat fly. Maria, who had been playing the guitar while Charlie was upstairs, asked Charlie if he had found out what the thing was. "Oh, nothing to worry about", he said casually hoping that the terror could not be seen in his eyes, "it was just a bat."

    In colleges around the country, most students are also workers.

    The reality of college can be pretty different from the images presented in movies and television. Instead of the students who wake up late, party all the time, and study only before exams, many colleges are full of students with pressing schedules of not just classes and activities, but real jobs, too.

    This isn't a temporary phenomenon. The share of working students has been on the rise since the 1970s, and one-fifth of students work year round. About one-quarter of those who work while attending school have both a full-course load and a full-time job. The arrangement can help pay for tuition (学费) and living costs, obviously. And there's value in it beyond the direct cause: such jobs can also be critical for developing important professional and social skills that make it easier to land a job after graduation. With many employers looking for students with already-developed skill sets, on-the-job training while in college can be the best way to ensure a job later on.

    But it's not all upside. Even full-time work may not completely cover the cost of tuition and living expenses. The study notes that if a student worked a full-time job at the federal minimum wage, they would earn just over $15, 000 each year, certainly not enough to pay for tuition, room, and board at many colleges without some serious financial aid. That means that though they're sacrificing time away from the classroom, many working students will still graduate with at least some debt. And working full time can reduce the chance that students will graduate at all, by cutting into the time available for studying and attending classes.

    There is little reward for attending but not finishing college. Students who wind up leaving school because of difficulty in managing work and class are likely to find themselves stuck in some of the same jobs they might have gotten if they hadn't gone at all. The difficulty of working too much while in school can create a cycle that pushes students further into debt without receiving any of the financial or career benefits.

    They still bite, but new research shows lab-grown mosquitoes are fighting dengue fever — a dangerous disease that they normally would spread. Dengue infections appear to be dropping fast in communities in Indonesia, Vietnam, Brazil and Australia that are filled with the specially grown mosquitoes.

    Researchers first injected (注射)mosquito eggs with Wolbachia bacteria that's common in insects and harmless to people in a lab. Infected females then pass the bacteria on through their eggs. Releasing enough Wolbachia carriers, both the females that bite and the males that don't, allows mating(交配)to spread the bacteria through a local mosquito population.

    Rather than using chemicals to wipe out pests, "this is really about transforming the mosquito," said Cameron Simmons of the nonprofit World Mosquito Program, which is conducting the research.

    The first success came from Australia. Mosquitoes carrying Wolbachia were released in parts of North Queensland starting in 2011, and gradually spread through the local mosquito population. Dengue is spread when a mosquito bites someone who is infected, and then bites another person, but somehow Wolbachia blocks that — and local spread has nearly disappeared in those North Queensland Communities, Simmons said.

    The studies are continuing in other countries. But the findings, presented at a meeting of the American Society for Tropical Medicine and Hygiene, suggest it's possible to turn at least some mosquitoes from a public health threat into annoying biters.

    The work marks "exciting progress," said Michigan State University professor Zhiyong Xi, who wasn't involved with the project but has long studied how Wolbachia can turn mosquitoes against themselves.

    More research is needed, specialists cautioned. "The results are pretty exciting — strong levels of reductions — but there clearly are going to be things to be learned from the areas where the reductions are not as great," said Penn State University professor Elizabeth McGraw.