Harvard researchers have created a tough, low-cost, biodegradable (可生物降解的) material inspired by insects' hard outer shells. The material's inventors say it has a number of possible uses and someday could provide a more environmentally friendly alternative to plastic. The material, made from shrimp ('虾) shells and proteins produced from silk, is called "shrilk." It is thin, clear, flexible and strong.

    A major benefit of the material is its biodegradability. Plastic's toughness and flexibility represented a revolution in materials science during the 1950s and '60s. Decades later, however, plastic's very durability (耐用性) is raising questions about how appropriate it is for one-time products such as plastic bags, or short-lived consumer goods, used in the home for a few years and then cast into a landfill where they will degrade for centuries. What is the point of making something that lasts 1,000 years?

    Shrilk not only will degrade in a landfill, but its basic components are used as fertilizer(肥料), and so will enrich the soil.

    Shrilk has great potential, the inventors said. Materials from which it is made are plentiful in nature, found in everything ranging from shrimp shells, insect bodies to living plants. That makes shrilk low cost, and its mass production possible should it be used for products demanding a lot of material.

Work on shrilk is continuing in the lab. The inventors said the material becomes flexible when wet, so they're exploring ways to use it in wet environments. They're also developing simpler production processes, which could be used for non-medical products, like for computer cases and other products inside the home. They're even exploring combining it with other materials, like carbon fibers, to give it new properties.

    Some people shy away from traveling alone while a few welcome it. So, what is it that makes traveling alone an attractive choice?

    First of all, the travel plan and all the decisions you make are yours alone. You don't need to worry about any other person or group. In other words, there are no arguments. Actually, you can be completely selfish.

    Traveling alone is also a great confidence builder. Yes, at times it can feel a bit lonely, but that is just one of many problems you will have to solve yourself, along with making your own preparations and setting your own goals.

    Besides, have you noticed that when you're on your own, people are more willing to start a conversation with you? Interestingly, people tend to keep a distance from couples and groups. However, the lone (独自的) traveler looks ready to connect with their fellow human beings and more likely to get into pleasant conversation about their trips.

    Here are two more exciting reasons why you should consider traveling alone. You will find you learn the language faster when you don't have someone else talking to you in your own language all the time. You are forced to communicate in the foreign language when you travel alone in a country that doesn't speak your native language. In addition, when you're on your own, you're free to meet someone who might turn out to be very important in your life.

    Of course, there may be things stopping you: You fear the unknown, or you have friends who may be upset by your decision to take off by yourself. You will have to make them believe the value of traveling done and allay any fears they might have, but with the technology at our fingertips, you can include them in the adventure.

    There are so many expressions in American English that sound good but are not.

    "Face the music" is a good example. When someone says they have to face the music, it does not mean they are going to a musical show or concert. To face the music means to accept the bad results of an action.

    Imagine a friend asks you to take care of her beautiful red sports car. She gives you the keys and says, "Thanks so much for watching my car while I'm away. But please do not drive it. It is a very fast car and you are not on the insurance (保险)."

    But you do not listen. You want to show it to some friends and pretend(假装) the car is yours. So, you drive it around town one night. As bad luck would have it, you lose control of the car and drive it into a stop sign. The damage is serious. When your friend returns you must tell her what you have done and "face the music".

    The "music" here is the result of your actions. It could be losing her friendship or paying for repairs to her sports car or both. Whatever the music is, you must face it.

    There are other American expressions that mean the same as "face the music".

    To "take your medicine" means to accept the results from something bad you have done. And if someone says, "You made your bed. Now lie in it." He means you created a bad situation and now you will experience the results, or as we say in American spoken English, you must deal with it!

    "Pay the piper" also means the same as "face the music". But, that expression has its own very interesting beginning. We will talk about that in the next Words and Their Stories.

    Cao Yuan, a PhD student from China, had two papers published on strange behaviour in atom-thick layers of carbon that have opened up a new field of physics.

    Pablo Jarillo-Herrero's group at MIT was already layering and rotating (旋转) sheets of carbon at different angles when Cao joined the lab in 2014. Cao's job was to find out what happened when one graphene (石墨烯) sheet was twisted only slightly wiht respect to the other, which one theory predicted would thoroughly change the material's behaviour.

    Many physicists doubted the idea. But when Cao set out to create the subtly twisted stacks, he spotted something strange. Exposed to a small electric field and cooled to 1.7 degrees above absolute zero, the graphene—which ordinarily conducts electricity—became an insulator. That by itself was surprising. But the best was yet to come: with a slight change to the field, the twisted sheets became a superconductor, in which electricity flowed without resistance.

    The ability to get atom-thick carbon into a complex electronic state through a simple rotation now has physics demanding to engineer exciting behavior in other twisted 2D materials. Some even hope that graphene could shed light on how more-complex materials superconduct at much higher temperatures. "There are so many things we can do," says Cory Dean, a physicist at Columbia University. "The opportunities at hand now are almost irresistible."

    Hitting graphene's “magic angle”—a rotation between parallel sheets of around 1.1°—involved some trial and error, but Cao was soon able to do it reliably. His experimental skill was extremely important, says his supervisor Jarillo-Herrero. Cao pioneered a method of tearing a single sheet of graphene so that he could create a stack of two layers, from which he could then fine-tune alignment (微调校准).

    Cao loves to take things apart and rebuild them. A heart, he is “a tinkerer”, his supervisor says. On his own time, this means photographing the night sky using homemade cameras and telescopes—pieces of which usually lie across Cao's office. "Every ime I go in, it's a huge mess, with computers taken apart and pieces of telescope all over his desk," says Jarillo-Herrero.

    Let us all raise a glass to AlphaGo and the advance of artificial intelligence. AlphaGo, DeepMind's Go-playing AI, just defeated the best Go-playing human, Lee Sedol. But as we drink to its success, we should also begin trying to understand what it means for the future.

    The number of possible moves in a game of Go is so huge that in order to win against a player like Lee. AlphaGo was designed to adopt a human—like style of gameplay by using a relatively recent development--deep learning. Deep learning uses large data sets," machine learning" algorithms （计算程序） and deep neural networks to teach the AI how to perform a particular set of tasks. Rather than programming complex Go rules and strategies into AlphaGo DeepMind designers taught AlphaGo to play the game by feeding it data based on typical Go moves. Then, AlphaGo played against itself, tirelessly learning from its own mistakes and improving its gameplay over time. The results speak for themselves.

    Deep learning represents a shift in the relationship humans have with their technological creations. It results in AI that displays surprising and unpredictable behaviour. Commenting after his first loss, Lee described being shocked by an unconventional move he claimed no human would ever have made. Demis Hassabis, one of DeepMind's founders, echoed this comment:"We're very pleased that AlphaGo played some quite surprising and beautiful moves."

    Unpredictability and surprises are—or can be—a good thing. They can indicate that a system is working well, perhaps better than the humans that came before it. Such is the case with AlphaGo. However, unpredictability also indicates a loss of human control. That Hassabis is surprised at his creation's behaviour suggests a lack of control in the design. And though some loss of control might be fine in the context of a game such as Go, it raises urgent questions elsewhere.

    How much and what kind of control should we give up to AI machines? How should we design appropriate human control into AI that requires us to give up some of that very control? Is there some AI that we should just not develop if it means any loss of human control? How much of a say should corporations, governments, experts or citizens have in these matters? These important questions, and many others like them, have emerged in response, but remain unanswered. They require human, not human - like, solutions.

    So as we drink to the milestone in AI, let's also drink to the understanding that the time to answer deeply human questions about deep learning and AI is now.

    Chinese media and Internet users on Monday decried（谴责）a lack of morals in society after a child was struck twice by two different trucks and left bleeding on the road as more than a dozen bystanders did nothing to help the seriously injured girl.

    The incident, captured by a surveillance camera and aired by Southern Television Guangdong (TVS), showed the two-year-old girl was knocked down and run over by a white truck on a narrow market street on the afternoon of Oct. 13, in Foshan City of Guangdong Province.

    The driver fled the scene of the accident, leaving the girl to bleed on the sidewalk. Over the next six minutes, more than a dozen people walked by the girl, yet not one individual did anything to help her. The girl was then hit a second time by another van before an elderly trash collector came to her aid and brought the attention of the girl's mother, according to the video and eyewitnesses.

    Doctors said that the girl, who was put on life support after being hospitalized, remains in a deep coma. The girl's parents, who are migrants living in the city, are now with her.

    Police said the drivers of both vehicles have been arrested. However, the apathy(冷漠) of the bystanders shown in the video has shocked the public, and people are questioning the morality of society.

    High moral standards were once considered as national pride in China where individuals known for selflessly helping others were adored（崇拜） by the public.

    But in recent years, the perception（观念）of a decline of morals has become a hot topic as profit and materialism are perceived to be affecting society's values.

    On Sept. 2. an 88-year-old man in central China collapsed, his face striking the pavement. Yet, no one came to his aid, and he ended up choking to death on the blood from his nose.

    Some have linked the absence of good Samaritans (模范人物)to a previous case in which a man trying to help an elderly woman who fell was accused of harming her.

    A strong chorus of opinion on the Internet says laws should exempt（免除）Samaritans from liability（责任）, yet laws themselves cannot solve society's morality dilemma.

    Cao Lin, a China Youth Daily commentator, said in a signed article published on Monday that the worry of liability should not be an excuse for not helping, and this case exposes the decline of humanity in Chinese society.