The researchers created a long-termstudy in which they invited families in 16 school districts in central Pennsylvania to participate. In each family, a teenager, a younger sibling, their mother and their father were interviewed at home and then asked about their activities and self-worth five times over a period of seven years.

    The study authors were surprised to discover that when fathers spent more time alone with their teenagers, the kids reported they felt better about themselves. Something about the father's role in the family seemed to improve self-esteem among the teenagers in the study, said study author Susan McHale, a professor of human development at Pennsylvania State University.

  “Time spent with Dad often involves joking, teasing and other playful interactions. Fathers, as compared to mothers, were more involved in leisure activities and had more friend-like interactions with their children, which is crucial for youth social development,” the study showed.

    But Marta Flaum, a psychologist in Chappaqua , New York, said, “How these findings reflect the real world is areal question. The sample in the study is so small and so unrepresentative of more families in the country today that I'm not sure how much we cangeneralizing from it. In my community, in Westchester County, I don't see parents and teenagers spending much time together at all. Parents are often working so hard and have less time to be together with their kids.”

    However, Flaum encourages parents to make time for their kids no matter how much work they have to do. “Research like this reminds us of how important it is. The time we have with themis so short, ” she said.

    Back in the 1860s, a British scientist named Henry Walter Bates noticed something interesting in the animal world: a kind of butterfly, Common Mormon, can change the pattern on its wings so that it looks like another butterfly species, the Common Rose, which is poisonous for birds to eat.

    Bates argued that animals develop this ability to protect themselves from being eaten. This theory had been widely accepted by scientists. But one question remains: how do these animals manage to do that?

    After more than 150 years, scientists are finally able to answer that question-it is all down to a gene(基因) called “doublesex", according to a study published on March 6 in the journal Nature.

    In fact, scientists have long known that genes are responsible for this useful ability. But until the new study, scientists hadn't been able to find out which genes in particular were responsible.

    Scientists at the University of Chicago compared the genetic structures of the Common Mormons that changed their wing patterns with those of ones that did not. And all the results pointed to a single gene, “doublesex”.

    This was much to the scientists' surprise. They used to expect that something as complex as this would be controlled by many different genes. For example, one gene would control the color of the upper part of the wing, one would do so for the lower part.

    However, the “doublesex” gene doesn't quite do everything by itself. Instead, it acts like a switch-it “tells” other genes to change the wing patterns. Isn't that clever?

    Scientists believe that this special ability of the “doublesex” gene on Common Mormon was developed throughout the long history of evolution. “The harmless species gains an advantage by resembling something predators(捕食者) avoid,” Sean Carroll, a scientist told Nature. “it was obvious evidence for natural selection.”

    I fondly remember road trips as a child, sitting in the sunny backseat of my mom's car, daydreaming about other worlds and fantastic adventures. As I've grown older, my daydreams have become increasingly occupied less with fantasy but more with the reality of my past and future. Nearly everyone daydreams about their future and reflects nostalgically (念旧地) or negatively on moments of the past. These moments can provide inspiration, but if you spend too much time daydreaming in this fashion, you may be reducing your success in the present.

    If you've ever planned a vacation, you're familiar with the impatient days tapping at your desk, dreaming of the lazy, relaxing days to come. Unfortunately, sometimes you end up comparing the real vacation to your imagined one, and it doesn't live up to the standard. Reflecting nostalgically on the past can also prevent present enjoyment. It is equally fun to reflect on past achievements or fun events, but it's possible to be so consumed with happy memories that you miss opportunities to create more.

    We've all made mistakes that we're ashamed of; reflecting on them is an important step in correcting those mistakes and becoming a better person. But dwelling（细想）too long on your past can also be negative. If you dwell too long on a past mistake, you can begin to equate（使等同）yourself with your past and feel farther away from the person you want to be. Train your brain to think quickly about the past and future, and take only the information and inspiration that you need in order to be the best person you can without resting on your glory moments or your mistakes.

    If your identity is not dependent on the past or future, every experience is new and every day is a blank page for you to write. A fun mental exercise is to always tell yourself that you're experiencing things for the first time. So take advantage of each moment you're given.

    Brian Greene, a professor of physics and mathematics at Columbia University, has created an online science education platform. He tries to "build a bridge" with things you know about, and then "bring you across that bridge to the strange place of modern physics."

    Recently I had a chance to ask Greene about wormholes (a hole which some scientists think might exist, connecting parts of space and time that are not usually connected), time travel and other mysteries of the universe. I asked him a million-dollar question: What if I went through a wormhole and prevented my parents from meeting? "Most of us believe that the universe makes sense," Greene said. Although there are several interesting theories about time travel, he added, the laws of physics would probably prevent something so illogical from taking place. The good news is that the time paradox（悖论） is open for future physicists to solve.

    When asked how physics could become more exciting for kids, Greene said that books by Stephen Weinberg, Leonard Susskind, and other physicists, "make it a great time for people who want to learn about big ideas but aren't yet ready, perhaps, to learn math."

    When I pointed out that some students still might find physics boring, Greene said that the key is to teach them about things that are strange. "The basic stuff is important," Greene said. "But I think it's really important to also describe the more modern ideas, things like black holes and the Big Bang. If kids have those ideas in mind, then at least some of them will be excited to learn all the details．"

    Greene has followed Albert Einstein's lead in trying to solve the mysteries of the universe. Now he wants kids to do the same. As Greene said, physics is "not just a matter of solving problems in an exam." It's about experimenting, showing an interest in strange phenomena（现象）-- and having fun!

    "I feel unlikable, lonely and hopeless," said Lisa, a bright teenager from a loving home. "It seems that nobody wants to become my friend. What's wrong with me?"

    Like Lisa, many of us experience loneliness. The truth is that all people, no matter what their age or character — even the most outgoing, wealthy and popular — experience loneliness at least sometimes. It's healthy and natural to want to be around people who care. After all, we've all heard "No man is an island." That's true. We all need others in our lives.

    Solomon, the wisest man who ever lived, explains that if we want friends, we must be friendly and reach out to others. But it has risk. Because we are often afraid of rejection (拒绝), many of us are unwilling to reach out to others. We take a safer way and wait for others to make friends with us. But if we want friends, we've got to get beyond this.

If making friends is your goal as well, you need to consider taking some measures (措施).

    Be willing to take the initiative (主动权). If you see someone whom you would like to know, don't wait for her to make the first move. Get close to her and begin a conversation. Let her know in a non­aggressive (无攻击性的) way that you are interested in being friends with her.

    Reach out to those who are lonely. When you see someone at school sitting alone, go over and talk to her. And don't let popularity decide whom you reach out to. You'll often be surprised at the beautiful qualities behind a shy appearance.

    Ask questions. Start your first conversation by asking this possible friend what she likes to do or asking about her family. Be sure to ask questions that cannot be replied with "yes" or "no". For example, don't ask "Do you have a dog?" Instead, say "So, tell me about your pets." Avoiding asking "yes" or "no" questions makes your possible friend not end your communication with a one­word answer.

    Many of you may have used Siri, a voice assistant of US tech company Apple. You only have to say "hey Siri" and it will answer to your command. However, we may be sacrificing our privacy to enjoy this convenience.

    According to a recent report by the Guardian, Siri can be accidentally triggered and start recording private conversations, such as discussions between doctors and patients. Some of these recordings are then given to workers outside the company to review.

    Apple claimed the data was used to help Siri improve, but users were not informed of this measure in the first place.

    Apple's Siri is not the only voice assistant to come under fire.

    In 2018, Alexa, a voice assistant developed by US tech company Amazon, recorded a private conversation between a couple and sent it to a stranger without their permission.

    These issues deepened concerns that tech companies are infringing users' rights of privacy.

    Many people have long feared that tech companies are listening and collecting data from private conversations, reported Forbes. Using this data, third party companies could then paint an accurate picture of users' habits and preferences in order to serve them more targeted advertisements, or even worse, sell this private data.

    Despite this risk, the popularity of voice assistant seems to be unstoppable.

    "In the near future, everything from your lighting to your air-conditioning to your refrigerator, your coffee maker, and even your toilet could be wired to a system controlled by voice," commented The Atlantic.

    Colin Horgan wrote on the blog site Medium that he believed people's daily lives will soon become a source of data.

    "The sounds of our homes, the symphony of life – laughing, crying, talking, shouting, sitting in silence – will no longer be considered memories, but data," he wrote.

    To deal with the issue, Blake Morgan, reporter for The Atlantic, believed that the answer is transparency.

    "All companies need to have messaging ready to explain to customers what they do with private data," she wrote on The Atlantic.