It's common knowledge that sleep problems can be caused by things such as stress, anxiety, or even using a smartphone before bedtime. But recently, a team of researchers discovered that genes could also be a cause of sleepless nights.

    The scientists, from Rockefeller University in New York, US, found that delayed sleep phase disorder（DSPD，睡眠相位后移综合症）, a condition that affects one's sleeping patterns, is passed down via a mutated（突变的）gene. DSPD sufferers wake up later and go to bed later than the average person. To come to their conclusion, the team studied a 46-year-old woman who is only usually able to fall asleep at 2 or 3 in the morning. It was discovered that the woman's body produces the hormone that helps her sleep at night up to 7 hours later than regular sleepers. The scientists found this was caused by a mutation in one of the woman's genes, one that helps regulate the “body clock”.

    Some of the woman's family members were also found to share the same mutation—and the same sleeping problems –leading the scientists to believe that sleep troubles are passed down through the generations.

    However, having this mutation doesn't mean you automatically have sleep problems. The team also found two people who had the mutation but reported no problems with their sleep.

    But while this is an interesting discovery, it offers no help to those who can't fall asleep at night—although there are a few things you could try to help you sleep earlier.

    BBC journalist Michael Mosley produced a TV documentary in May in which he talked about his battle with insomnia（失眠）and the techniques he used. “I avoid social media for at least an hour before bed, I do mindfulness exercises, and if I wake up in the middle of the night, I read a book for an hour or so,” he wrote in an article for the Radio Times.

    A research project jointly carried out by scientists from several British universities and institutes has drawn people's attention to the toothbrush again.

    Researchers have found that your toothbrush is home to more than 100 million bacteria. But there are hundreds of microorganisms in the mouths and your toothbrush probably won't make you sick unless there is an unhealthy balance of bacteria. Our immune system can usually take care of bacterial invaders. However, if others use your toothbrush, or you use someone else's, bacteria can be spread.

    They have also found the toothbrush holders are the third-most dirty household items (behind dish sponges and kitchen sinks), thus advocating cleaning the toothbrush holder regularly.

    The storage of your toothbrush in your bathroom is also important. Here are some storage tips from the researchers to keep your toothbrush as healthy as possible:

    Put your toothbrush as far away as possible from the toilet flushing.

    Let your toothbrush dry thoroughly between brushings.

    Don't use toothbrush covers, which can create a perfect breeding ground for bacteria.

    Keep your toothbrush upright in a holder rather than lying down.

    Keep toothbrushes separate. If toothbrushes touch, they can exchange and spread bacteria.

    There are products available that claim to sanitize（消毒）your toothbrush. While some of these products do kill some bacteria, there is no evidence that using them will reduce your risk of illness, according to the researchers.

    They recommend replacing your toothbrush every three to four months or more often if you are sick or if you have a weakened immune system. Children's toothbrushes may need to be replaced more often than adult brushes.

    One of the most important things in the world is friendship. In order to have friends, you have to be a friend. But how can you be a good friend at school？

Listen﹣Listen when they are talking. Don't say anything unless they ask you a question. Sometimes it's not necessary for you to have anything to say; they just need someone to talk to about their feelings.

    Help them﹣If your friend is ever in need of something, be there to help them. You should try to put them first, but make sure you don't do everything they want you to do. Try to take an extra pencil or pen with you to classes in case they forget one. Have a little extra money in your pocket in case they forget something they need.

    Be there for them﹣Be there for your friends to help make them feel better in hard times. Marilyn Monroe, a famous U.S. actor, once said, "I often make mistakes. Sometimes I am out of control, but if you can't stay with me at my worst, you are sure not to deserve to be with me at my best." Always remember this! If you don't want to stay with your friends when they're in hard times, then you don't deserve to be with them when they're having a good time!

    Make plans﹣Try to make plans with your friends. Go shopping, go for ice cream, have a party, go to a movie and so on. Take time to know each other even better by doing something you both enjoy. By planning things together, you both can have a good time. And you'll remember these things when you're all old!

    NOT all memories are sweet. Some people spend all their lives trying to forget bad experiences. Violence and traffic accidents can leave people with terrible physical and emotional scars. Often they relive these experiences in nightmares.

    Now American researchers think they are close to developing a pill, which will help people forget bad memories. The pill is designed to be taken immediately after a frightening experience. They hope it might reduce ,or possibly erase(抹去),the effect of painful memories.

    In November, experts tested a drug on people in the US and France. The drug stops the body releasing chemicals that fix memories in the brain. So far the research has suggested that only the emotional effects of memories may be reduced, not that the memories are erased.

    The research has caused a great deal of argument. Some think it is a bad idea, while others support it.

    Supporters say it could lead to pills that prevent or treat soldiers' troubling memories after war. They say that there are many people who suffer from terrible memories.

    "Some memories can ruin people's lives. They come back to you when you don't want to have them in a daydream or nightmare. They usually come with very painful emotions," said Roger Pitman, a professor of psychiatry at Harvard Medical School. "This could relieve a lot of that suffering."

    But those who are against the research say that changing memories is very dangerous because memories give us our identity (特质). They also help us all avoid the mistakes of the past.

    "All of us can think of bad events in our lives that were horrible at the time but make us who we are. I'm not sure we want to wipe those memories out, "said Rebecca Dresser, a medical ethicist.

    It was rainy, and I had no desire to drive up the winding mountain road to my daughter Carolyn's house. But she had insisted that I come to see something at the top of the mountain.

    So here I was, reluctantly making the two-hour journey through fog that hung like veils. By the time I saw how thick it was near the summit, I'd gone too far to turn back.

    Nothing could be worth this, I thought as I inched along the dangerous highway.

    "I'll stay for lunch, but I' m heading back down as soon as the fog lifts," I announced when I arrived.

    "But I need you to drive me to the garage to pick up my car," Carolyn said, "Could we at least do that?"

    "How far is it?" I asked.

    "About three minutes," she said, "I'll drive—I'm used to it."

    After ten minutes on the mountain road, I looked at her anxiously. "I thought you said three minutes."

    She grinned. "This is a detour."

    Turning down a narrow track, we parked the car and got out. We walked along a path that was thick with old pine needles. Huge black-green evergreens towered over us. Gradually, the peace and silence of the place began to fill my mind.

    Then we turned a comer and stopped—and I gasped in amazement.

    From the top of the mountain, sloping for several acres across the mountain side and valleys, were rivers of flowers in numerous colors. It looked as though the sun had tipped over and spilled gold down the mountainside.

    A series of questions filled my mind. Who created such beauty? Why? How?

    As we approached the home that stood in the center of the property, we saw a sign that read: "Answers to the Questions I Know You Are Asking."

    The first answer was: "One Woman—Two Hands, Two Feet, and Very Little Brain." The second was: "One at a Time." The third: "Started in 1958."

    As we drove home, I was so moved by what we had seen. I could scarcely speak. "She changed the world." I finally said, "one bulb (球茎) at a time. She started almost 40 years ago, probably just the beginning of an idea, but she kept at it."

    The wonder of it would not let me go. "Imagine," I said, "if I'd had a vision and worked at it, just a little bit every day, what might I have accomplished?"

    Carolyn looked at me sideways, smiling. "Start tomorrow," she said. "Better yet, start today."

    There are plenty of mindless activities to keep a child busy in this information age. Yet despite the competition, my 8-year-old daughter Alice wants to spend her leisure time writing short stories. She wants to enter one of her stories into a writing contest, a competition which she won last year.

    As a writer, I know about winning contests—and about losing them. I know what it is like to work hard on a story only to receive a rejection letter from the publisher. I also know the pressure of trying to live up to a reputation created by previous victories. What if she doesn't win the contest again? That's the strange thing about being a parent. So many of our own past scars and destroyed hopes can resurface in our children.

    A revelation (启示) came last week when I asked her, "Don't you want to win again?" "No," she replied. "I just want to tell the story of an angel going to first grade."

    I had just spent weeks correcting her stories as she spontaneously (自发地) told them. Telling myself that I was an experienced writer guiding the young writer across the hall, I offered suggestions for characters, conflicts and endings for her tales. The story about a fearful angel starting first grade was quickly "guided" by me into the tale of a little girl with a wild imagination taking her first music lesson. I had turned her contest into my contest without even realizing it.

    Staying back and giving kids space to grow is not as easy as it looks. Because I know very little about farm animals who use tools or angels who go to first grade, I had to accept the fact that I was co-opting (借鉴) my daughter's experience.

    While stepping back was difficult for me, it was certainly a good first step that I will quickly follow with more steps, putting myself far enough away to give her room but close enough to help if asked. All the while I will be reminding myself that children need room to experiment, grow and find their own voices.