Dolphins(海豚) live in a dark underwater world. It's often impossible to see each other or anything else around them, so sound plays an important role in their survival. To communicate with each other, dolphins produce all kinds of sounds.

    Only other dolphins understand what the sounds mean. Scientists haven't uncovered their secret communication, except for one kind of whistle. It might last less than a second, but this whistle is a big deal. Why? Because these whistles are actually names of dolphins - and every dolphin has one. Scientists call these sounds a “signature whistle.” When other dolphins hear the whistle, they know which dolphin is calling.

    Dolphins often hunt by themselves but still need to stay connected to the group. Since they can't always see each other, dolphins use their signature whistles to check in with other dolphins hundreds of yards away. “In coastal areas, dolphins exchange whistles even when they're a third of a mile apart,” says Greg Campbell, who studies animals. That means dolphins shout out to group members that might be nearly five football fields away.

    What's amazing is who names the baby dolphin. Not the mother. Not an auntie dolphin or another group member. Scientists believe the baby dolphin itself comes up with the signature whistle. Like human babies, a baby dolphin plays with sounds throughout its first year. While testing its sound skills, a baby dolphin is doing something amazing. It's creating or figuring out its signature whistle. How or why it chooses its signature whistle is not clear. Studies show that most of the time the signature whistle is nothing like its mother's or group members' whistles.

    When the baby dolphin is about a year old, its signature whistle is set. It repeats it often so the other dolphins learn to recognize it.

    Deciphering(破译) dolphin names is just the beginning of figuring out what dolphins communicate about. Do they chat about sharks? Discuss the tides? Maybe they even have a name for people. Someday scientists are to decipher the rest of dolphins' communication.

    Peter Thiel,the billionaire co-founder of PayPal,plans to live to be 120.Compared with some other tech billionaires,he doesn't seem particularly ambitious.Dmitry Itskov,the “godfather” of the Russian Internet,says his goal is to live to 10.000;and Sergey Brin,co-founder of Google,hopes to someday "cure death.

    They aren't being ridiculous.Their search is based on real science that could fundamentally change what we know about life and about death.It's hard to believe,though,since the human search for immortality is both ancient and filled with disastrous failures.Around 200 B.C.,the first emperor of China,Qin Shi Huang,accidentally killed himself trying to live forever;he poisoned himself by eating mercury（水银）pills.Centuries later, the search for eternal life wasn't much safer: In J492,Pope Innocent VIII died after blood transfusions from three healthy boys whose youth he believed he could absorb.

    But historical examples haven't discouraged some of the biggest names in Silicon Valley.Thiel,for example,has given $3.5 million to the Methuselah Foundation.Aubrey de Grey,Methuselah's co-founder,says SENS,the nonprofit's main research is devoted to finding drugs that cure several types of age-related damage:"Loss of cells, excessive（过多的）cell division,inadequate cell death,garbage inside the cell,garbage outside the cell,...The idea is that the human body,being a machine,has a structure that determines all aspects of its function,so if we can restore that structure—at the molecular（分子的）and cellular（细胞的）level—then we will restore function too,so we will have comprehensively renewed the body."

    But SENS,which has an annual operating budget of $5 million,is small,compared with the Brin-led Project Calico,Google's attempt to “cure death,”which is planning to pump billions into a partnership with medicine giant AbbVie.Google is secretive,but it's said to be building a drug to copy a gene associated with exceptional life span.

    Then there's the Glenn Foundation for Medical Research,started by Paul F.Glenn in 1965.Since 2007,the foundation has distributed annual "Glenn Awards,"$60,000 to independent researchers doing promising work on aging.The Glenn Foundation also works closely with the Ellison Medical Foundation,a far younger institution (founded in 1997).Ellison's passion project gives out hundreds of thousands of dollars each year to scholars seeking research on aging.Their decision to fund independent research may be paying off.Research projects funded by Ellison and Glenn appear to be developing into a testable means to stave off old age—for lab mice.The question is: Can those lab results be repeated in humans?

    AlphaGo is a computer program that plays the board game Go.

    In March, 2016, the pride of humankind was crushed (粉碎) by a computer. Google's AlphaGo defeated the South Korean grandmaster (围棋大师) Lee Sedol four games to one, as the world looked on with shock and awe (敬畏). Artificial intelligence (AI, 人工智能) had suddenly reached a new and unexpected height.

    But as smart as AlphaGo is, it's no longer the best Go “player” in the world. Google's artificial intelligence group, DeepMind, has created the next generation of its Go-playing program, called AlphaGo Zero. The new AI program is unique in the way it learned to play Go. Instead of learning from thousands of human matches, as its predecessor (前任) did, AlphaGo Zero mastered Go in just two days without any human knowledge of the game and defeated AlphaGo by day three, reported The Guardian. It then went on to defeat AlphaGo 100 games to zero.

    To learn how to play Go, AlphaGo Zero played millions of matches against itself using only the basic rules of the game to rapidly create its own knowledge of it. Like the previous version, it used “reinforcement (增强) learning to become its own teacher,” according to DeepMind's website.

    “It's more powerful than previous approaches,” David Silver, AlphaGo's lead researcher, told The Guardian, “because by not using human data, or human expertise in any fashion, we've removed the constraints (约束) of human knowledge and it is able to create knowledge itself.”

    AlphaGo Zero's approach to self-learning is a significant advancement in AI that could be applied to help solve some of the world's biggest problems, according to a recent research report published in the journal Nature. For example, DeepMind co-founder Demis Hassabis argues that AlphaGo Zero could probably find cures for a number of serious diseases within weeks, according to The Telegraph. Indeed, the AI is now being used to study protein folding, which is connected to diseases such as Parkinson's and Alzheimer's.

    So now that AI has exceeded (超过) the bounds of human knowledge, perhaps the question is not about what AI can learn from humans, but what humans can learn from AI. We can only wait and see.

    My daughter had a bullying(欺凌) problem a couple of years ago. She kept receiving rude text messages from kids at school. Dealing with school bullying wasn't easy, but I finally ended it. When you realize things are serious, it is no time to be silent.

    If your kids are also receiving such text messages, take them directly to the headmaster and show him. Describe to him how it is affecting your kids. Tell him you will not tolerate it and that you want him to put an end to it now.

    School bullying is a dangerous and serious issue these days, and any good headmaster will take your charges seriously. He will probably address the issues with the parents. If they are crappy(糟糕的) parents, then they may do nothing to their child. You may have to repeat this process several times, but you need to keep a check on those text messages and don't allow your child to delete them.

    Now it is time to draw your child close and take care of him/her, because he/she needs it. My daughter did not like me being involved either, but you are the only person your kid can depend on to solve this problem, so do it and mean business. Always be polite, but straightforward. The headmaster and parents must know you mean business.

    If repeated meetings with the headmaster (and parents, if he allows it) do not work, then I would consider hiring a lawyer. That will send the message loud and clear. When you are talking about financial loss, most parents will stand up and take notice and act to keep their kids under control!

    I know a lawyer is a big expense and not something you do lightly, but when bad things like school bullying are happening to your children, you must act and act quickly.

    "Have a nice day！" may be a pleasant gesture or a meaningless expression. When my friend Maxie says "Have a nice day" with a smile, I know she sincerely cares about what happens to me. I feel loved and safe since another person cares about me and wishes me well.

    "Have a nice day. Next！" This version of the expression is spoken by a salesgirl at the supermarket who is rushing me and my groceries out the door. The words come out in the same tone (腔调) with a fixed procedure. They are spoken at me, not to me. Obviously, the concern for my day and everyone else's is the management's attempt to increase business.

    The expression is one of those behaviors that help people get along with each other. Sometimes it indicates the end of a meeting. As soon as you hear it, you know the meeting is at an end. Sometimes the expression saves us when we don't know what to say. "Oh, you just had a tooth out? I'm terribly sorry, but have a nice day. "

    The expression can be pleasant. If a stranger says "Have a nice day" to you, you may find it heart­warming because someone you don't know has tried to be nice to you.

    Although the use of the expression is an insincere, meaningless social custom at times, there is nothing wrong with the sentence except that it is a little uninteresting. The salesgirl, the waitress, the teacher, and all the countless others who speak it without thinking may not really care about my day. But in a strange and comfortable way, it's nice to know they care enough to pretend they care when they really don't care all that much. While the expression may not often be sincere, it is always spoken. The point is that people say it all the time when they like.

    I was in the middle of the Amazon (亚马逊) with my wife, who was there as a medical researcher. We flew on a small plane to a faraway village. We did not speak the local language, did not know the customs, and more often than not, did not entirely recognize the food. We could not have felt more foreign.

    We were raised on books and computers, highways and cell phones, but now we were living in a village without running water or electricity It was easy for us to go to sleep at the end of the day feeling a little misunderstood.

    Then one perfect Amazonian evening, with monkeys calling from beyond the village green, we played soccer. I am not good at soccer, but that evening it was wonderful. Everyone knew the rules. We all spoke the same language of passes and shots. We understood one another perfectly. As darkness came over the field and the match ended, the goal keeper, Juan, walked over to me and said in a matter-of-fact way, "In your home, do you have a moon too?" I was surprised.

    After I explained to Juan that yes, we did have a moon and yes, it was very similar to his, I felt a sort of awe (敬畏) at the possibilities that existed in his world. In Juan's world, each village could have its own moon. In Juan's world. the unknown and undiscovered was vast and marvelous. Anything was possible.

    In our society, we know that Earth has only one moon. We have looked at our planet from every angle and found all of the wildest things left to find. I can, from my computer at home, pull up satellite images of Juan's village. There are no more continents and no more moons to search for, little left to discover. At least it seems that way.

    Yet, as I thought about Juan's question, I was not sure how much more we could really rule out. I am, in part, an ant biologist, so my thoughts turned to what we know about insect life and I knew that much in the world of insects remains unknown. How much, though? How ignorant (无知的) are we? The question of what we know and do not know constantly bothered me.

    I began collecting newspaper articles about new species, new monkey, new spider…, and on and on they appear. My drawer quickly filled. I began a second drawer for more general discoveries: new cave system discovered with dozens of nameless species, four hundred species of bacteria found in the human stomach. The second drawer began to fill and as it did I wondered whether there were bigger discoveries out there, not just species, but life that depends on things thought to be useless, life even without DNA. I started a third drawer for these big discoveries. It fills more slowly, but all the same, it fills.

    In looking into the stories of biological discovery, I also began to find something else, a collection of scientists, usually brilliant occasionally half-mad, who made the discoveries. Those scientists very often see the same things that other scientists see, but they pay more attention to them, and they focus on them to the point of exhaustion (穷尽), and at the risk of the ridicule of their peers. In looking for the stories of discovery, I found the stories of these people and how their lives changed our view of the world.

    We are repeatedly willing to imagine we have found most of what is left to discover. We used to think that insects were the smallest organisms (生物), and that nothing lived deeper than six hundred meters. Yet, when something new turns up, more often than not, we do not even know its name.