Lights out, phones on. Many teenagers reach for their smartphones or tablets at bedtime, but it may be a good idea to switch off before you hit the pillow.

    According to a study by researchers at Murdoch and Griffith Universities in Australia, using mobile devices late at night could harm teenagers' sleep and lead to an increased risk of mental health problems.

    The study was carried out on more than 1,000 Australian high school students aged between 13 and 16. It lasted four years as student participants moved from Year 8 to Year 11.

    During the study, students were asked what time of the night they received or sent text messages and phone calls, and how well they slept.

    The results are impressive. When the study started in Year 8, more than 85 percent of the students had a mobile pone and around one-third of these students never used phones after lights out. In contrast, 93 percent of Year 11 students had a mobile phone and only 22 percent of then had no late night mobile use when the study concluded four years later.

    As the levels of mobile phone use increased, there was a growth in poor sleep behavior among the students. Meanwhile, mental health problems also increased. Students in Year 8 who were more likely to use phones at night were found to have higher levels of depression (抑郁) and lower self-esteem (自尊心) one year later.

    Lynette Vernon, lead author of the study, explained that phones affect our sleep patterns because of the unnatural blue light they produce. This light could affect the level of hormones (荷尔蒙) in the body, disrupting (打乱) its balance.

     “The more you sit in bed and watch TV, play with your tablet, and play with your phone at three o'clock in the morning, the more these things affect the slow waves of your sleep pattern and give your poor quality sleep,” Mark Levi, a Sydney-based sleep doctor said.

    Based on the findings, the researchers suggested parents should focus on guiding their children's use of mobile devices.

    According to Vernon, the solution is not simply to ban teenagers from using their devices, but teach them better ways of using them

     “Back when they're aged 7 to 10, you have to be a role model. If you put your phone away at night and it doesn't go into your bedroom, it becomes normalizedin the household and you have a much easier job,” he told The Guardian.

    Last year, Claire Noble-Randall woke up at 5:30 am every morning. She had to catch two buses to arrive in time for first-period chemistry at Ingraham High School in Seattle, US.

    Ingraham starts at 8 am, but Noble-Randall often didn't go to sleep until after midnight. “It was really hard not to fall asleep in class,” she said.

Her mom solved the problem this year when she discovered that other parents had hired a private city tour bus to take their children to the school.

    “Now, she leaves the house at a much more reasonable time 7:10 in the morning…to catch the little tour bug at 7:23 am,” said her mother, Noelle Noble.

    That may be one way to help students get more sleep. But more than 3,300 people have signed an online petition (请愿) looking for a better solution from the Seattle school district. Those who have signed the petition want all high schools and middle schools to start no earlier than 8:30 am. Most of Seattle's high schools and middle schools start at 8 am or earlier.

    Later start times for teenagers is an idea that some parents around the nation, have wanted for years. They've provided plenty of scientific evidence that teenagers tend to be night owls and delayed start times improve their health, mood, attention, and, in some cases, learning.

    But attempts to delay start times for teenagers haven't worked. Coaches don't want late dismissals (放学) cutting into sports practices; community groups don't want to wait longer for gyms and fields and before- and after-school programs don't want to change their schedules.

    This time, however, they've got Seattle School Board. President Sharon Peaslee on their side. She herself is the mother of two high school students. Peaslee hopes other board members will pass her plan calling on the district to find a way to make the changes.

    That children are the hopes of our tomorrow is statement that is repeated time and again. And it is an axiom(格言); they are our pillars of the coming time. But then do we train them into becoming healthy human beings?

    Healthy human beings here are not meant the physical well being, but the good human being, that is, one with virtues and values keeps them in the state of working towards the benefit of humanity.

    How can children absorb within themselves the virtues and values? Well, this is the primary responsibility of parents and other immediate family members, followed by school authorities. The values and virtues of an individual is sown in their childhood and as they grow up.

    Depending on the way we bring up our children, we decide our own future. It is vital that in the formative years we give them quality time and attention. We teach them to discriminate between the good, bad and the ugly. We have to teach them use positive emotive like love and compassion and teach them actions of kindness and generosity. At the same time we have to help them do away with the negatives of hatred, anger, jealousy, selfishness, etc.

    Your child is like a plant. You sow the seeds and also reap the benefits of its growth and development. First and foremost you as a parent have to realize your responsibility in nurturing a child to grow into a good human being. And it is just not up to anyone of the parents, but both together to inculcate(谆谆教诲)the values and virtues into your child.

    Children start out as natural scientists, eager to look into the world around them. Helping them enjoy science can be easy; there's no need for a lot of scientific terms or expensive lab equipment. You only have to share your children's curiosity. Firstly, listen to their questions. I once visited a classroom of seven-year-olds to talk about science as a job. The children asked me “textbook questions” about schooling, salary and whether I liked my job. When I finished answering, we sat facing one another in silence. Finally I said, “Now that we're finished with your lists, do you have questions of your own about science?”

    After a long pause, a boy raised his hand, “Have you ever seen a grasshopper （蚱蜢）eat? When I try eating leaves like that, I get a stomachache. Why?”

    This began a set of questions that lasted nearly two hours.

    Secondly, give them time to think. Studies over the past 30 years have shown that, after asking a question, adults typically wait only one second or less for an answer, no time for a child to think. When adults increase their “wait time” to three seconds or more, children give more logical, complete and creative answers.

    Thirdly, watch your language. Once you have a child involved in a science discussion, don't jump in with “That's right” or “Very good”. These words work well when it comes to encouraging good behavior. But in talking about science, quick praise can signal that discussion is over. Instead, keep things going by saying “That's interesting” or “I'd never thought of it that way before”, or coming up with more questions or ideas.

    Never push a child to “Think”. It doesn't make sense, children are always thinking, without your telling them to. What's more, this can turn a conversation into a performance. The child will try to find the answer you want, in as few words as possible, so that he will be a smaller target for your disagreement.

    Lastly, show; don't tell. Real-life impressions of nature are far more impressive than any lesson children can learn from a book or a television program. Let children look at their fingertips through a magnifying glass（放大镜）, and they'll understand why you want them to wash before dinner. Rather than saying that water evaporates（蒸发）, set a pot of water to boil and let them watch the water level drop.

    Something's happening at the lowest point on our planet, some 1,388 feet below sea level. The Dead Sea, a salt lake close to Israel, Jordan and the West Bank, is shrinking at an alarming rate—about 3.3 feet per year, according to the environmentalist group EcoPeace Middle East.

    “It's not just like one country is punishing the Dead Sea; it's more like the whole region,” said photographer Moritz Küstner, who visited the area in February to work on his series “The Dying Dead Sea”.

    The Dead Sea needs water from the other natural sources surrounding it, such as the Jordan River basin. But around the 1960s, the courses of some water sources it relied upon were diverted. Israel, for instance, built a pipeline during that time so it could supply water throughout the country.

    Mineral extraction(提取)industries are another main reason why the water levels are declining, experts say. The Dead Sea's minerals have been popular for their medical power and can often be found in cosmetics(化妆品)and other consumer products.

    And then, of course, there's the Middle East's hot, dry climate, which makes it difficult for the lake to refill itself. Last year, Israel and Jordan signed a $ 900 million deal in an effort to stabilize the Dead Sea's water levels. It involves building a canal from the Red Sea to the Dead Sea which would be able to not only supply water to Israel and Jordan but also to pump much needed water—some 300 million cubic meters annually—into the Dead Sea.

    “This is the most important and significant agreement since the peace treaty with Jordan (in 1994),” said Silvan Shalom, Israel's energy and water resources minister at the time. Whether the canal—estimated to take three years to complete—will work out positively and as planned remains to be seen.

    For now, Küstner shows us that the Dead Sea remains very much a place of interest, with people from all over the world going there to swim in its salty waters.

    For the first time, China's South Pole researchers can eat fresh vegetables grown regularly, according to Wang Zheng, the grower, who came home last month after a 400-day mission in Antarctica.

    "Growing vegetables in Antarctica reminded me of The Martian, a sci-fi movie about an astronaut who survives alone on Mars by eating potatoes he grows there," Wang said on Friday. "I totally understand the main character of the movie, I understand how he feels when he watches a small green plant grow in a fragile man-made environment,'' said the 40-year-old doctor. But he admitted that the conditions he faced in the Antarctic were much better than those in the film.

    Wang said the growth chamber(生长室) at the Zhongshan Station, had only a low yield when it was established in 2013. The amount was too small to make it possible for researchers to have vegetable dishes. To increase the yield, he reduced the number of vegetable varieties and focused on only some fast-growing ones, which makes the output stable. As a result, during much of his stay there, at least one vegetable dish, such as cucumbers, lettuce or cabbage, was served at every meal for a group of 18 researchers.

    Wang, an orthopedist, said he knew nothing about botany or farming before he arrived at the station in December, 2014. "I was given this job probably because my office is next to the growth chamber, and as a doctor, I had more spare time than others," Wang said. He considered many factors, such as light, temperature and humidity. Light music is played in the 16-square - meter greenhouse around the clock. "Mild music is good for vegetable growth," he said. "We also played Buddhist music, which has soft melody."

    "Growers before me did very good work. My job was to maintain the chamber and keep everything working." Before the  harvest, researchers had a very limited vegetable supply—mostly potatoes and cabbage, which taste awful after months of storage. "Because of our success in growing vegetables, we can have fresh vegetables every day," he said. "The Russian station is no more than one kilometer away from ours. We even had enough vegetables to invite our Russian colleagues for dinner."