On a Saturday morning earlier this September, the world got its first look at the Strati. This electric vehicle is unlike any other currently on the road. It rolls on four wheels, but its body and chassis(底盘) weren't built in a factory. Instead, Strati's designers used a technology called 3-D printing. It created those parts of the car in one piece, from the ground up.

    “Compared to a typical vehicle on the road, the Strati definitely looks different,” says Greg Schroeder, a senior research engineer at the Center for Automotive Research in Ann Arbor, Mich. He did not work on the new car. His organization studies trends and changes in th e auto industry.

    It took 44 hours to print the new car at the International Manufacturing Technology Show in Chicago. Over the next few days, the car's designers installed additional parts. These included the car's engine, brakes and tires. Then, early on September 13, Jay Rogers climbed into the car, started its engine and drove the vehicle onto the street. Rogers helped found Local Motors. It's the Arizona-based company behind the Strati. Two weeks later, his team printed a second Strati, and just as fast, at a fair in New York City.

    Justin Fishkin, a local Motors official, sees the Strati as a window into the future. Today, car buyers are limited in their choice of a vehicle. They can order only what car companies have already designed. But in the future, he says, you may be able to design your own car online and then get it printed to order.

    Manufacturing experts say 3-D printing has begun to revolutionize how they make things. The technology has been around for decades. But these machines used to be so expensive that only large companies could afford them. In the last few years, though, that has changed. Many of the machines are now inexpensive enough for small companies—or even individuals —to own. Some local libraries make them available to the public. High Schools are beginning to use them in classrooms. Wide access to these printers means people can now design and print a wide variety of new things.

    The car's printer is a one-of-a-kind device.

    The technology behind the 3-D printer used in Chicago is an example of additive manufacturing. This proce ss builds solid objects, slice by slice, from the bottom up. (“Strati” means layers, in Italian.) A mechanical arm moves a nozzle from one side to another, back and forth. As it moves, the nozzle deposits a liquid—often melted plastic or metal (but it could be food, concrete or even cells) —that quickly hardens or bonds to become solid or semi-solid. This creates a single, thin layer. Once a layer is complete, the printer starts depositing the next one.

     “There's a lot of interest in 3-D printing in the auto industry,” says Schroeder. Right now, the technology is particularly useful for building models of cars or car parts.

    To compete with current auto manufacturers, the 3-D printer would have to increase in a hurry, Schroeder says. By contrast, he notes, a Ford F-150 pickup truck rolls off an assembly line at a rate of roughly one per minute. To print as many Stratis would require many more printers. Schroeder says he doesn't see 3-D printing soon taking over for such high-volume manufacturing. But, he adds, “Who knows what will h appen in the long term?”

    Scientists at Oak Ridge National Laboratory in Tennessee designed the 3-D printer used in Chicago. Lonnie Love, a research scientist at the lab, led the effort.

    Additive manufacturing often is slow and expensive. It also may produce materials that are unreliable, Love says. So for two years, his team searched for ways to make 3-D printing better. They built new machines and tested them over and over.

    All of that work paid off: their new machine is fast and uses less expensive material than earlier printers. In addition, it prints a plastic embedded with fibers of carbon to produce a stronger material. This helps ensure the material won't crack or break under pressure.

    Wild mangoes come from the foothills of the Himalayas. They are by far the most important fruit in India, and have been cultivated there for four thousand years. The arrival of the mango tree in other parts of the world was probably due to the Portuguese who carried mangoes via Goa to Africa, from where they eventually reached the New World. Mango trees are now so well established in many tropical countries that it might appear that they have always been there.

    Like many tropical trees, the mango tree is multi-purpose product. Its wood is used in boat building, and its leaves can be fed to cattle. Most of the mango crop is consumed in the areas where it is grown, but in recent years mangoes have gained in popularity across the world as people in mild climate become increasingly eager to enjoy the delight of the fresh fruit.

    The global market for mangoes is very profitable, and mango producers are keen to make use of the fruit's growing popularity. Modern shoppers not only appreciate the fruit's high nutritional value(the mango is a good source of vitamin A and C, protein and fibre), but also expect it to look and taste perfect. Therefore producers now select only the best quality seedlings which have the most chance of developing into good quality fruit.

    Mangoes are high in fiber, thus making them very good for the heart. The high fiber content is also helps easing constipation. They have high pectin(果胶) and vitamin C content that reduces the blood cholesterol levels and serves as an immune booster. This fruit is rich in anti-oxidants, vitamins, minerals and contain an enzyme(酶) that has stomach soothing properties. These enzymes act as a digestive aid and digestive proteins.

    Although the mango tree has spread from its native Himalayan foothills to the tropics, delivering the fresh fruit to the world's supermarkets presents a challenge, as it does not travel well. Producers transport the fruit by speedy but costly air freight (货运)for minimum delay rather than risk the cheaper but slower road or shipping routes which, can result in damage to the fruit.

    Mangoes are usually in storage for some time after their arrival at their destination. The fruit must be kept cold, or the sweet, juicy flesh will soon become over ripe and the mangoes will be unfit for sale. Fortunately, extremely effective refrigeration is now available and this is the best way of preventing the fruit from going bad before it reaches the supermarket shelves.

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The Metropolitan Museum of Art
		1000 Fifth Avenue New York, NY 10028 211-535-7710 www.metmuseum.org Entrances Fifth Avenue at 82nd Street Hours Open 7 days a week. Sunday-Thursday 10:00-17:30 Friday and Saturday 10:00-21:00 Closed Thanksgiving Day, December 25, January 1,and the first Monday in May.
Admission $25.00 recommended for adults, $12.00 recommended for students, includes the Main Building and The Cloisters(回廊）on the same day; free for children under 12 with an adult. Free with Admission All special exhibitions, as well as films, lectures, guided tours, concerts, gallery talks, and family/children's programs are free with admission. Ask about today's activities at the Great Hall Information Desk.
	The Cloisters Museum and Gardens     The Cloisters museum and gardens is a branch of The Metropolitan Museum of Art devoted to the art and architecture of Europe in the Middle Ages. The extensive collection consists of masterworks in sculpture, colored glass, and precious objects from Europe dating from about the 9th to the 15th century.
Hours: Open 7 days a week. March-October10:00-17:15 November-February 10:00-16:45 Closed Thanksgiving Day, December 25, and January 1.

We are interested in the preservation of the biodiversity on Earth. What I've been working on is rats. Just looking at rats, you can understand continental drift and climate change. We've actually rediscovered rats that were thought to be extinct. Darwin was the last one to document them on the Galapagos Islands. People have gone there for hundreds of years and not seen one. In 1997, I went there with my mentor(导师) and another graduate student. Everyone thought I was crazy, why look for something that doesn't exist? They wouldn't even give us permits. Our plan was to stop on a beach for a day and then hike up to the top of an extinct volcano where very few people had been: We were on a picturesque, isolated beach. We set out the traps just to see what we might find. The next morning, I checked my traps! I immediately ran back to my mentor. When he looked in the mental trap—I will never forget his face— It looked like he'd seen a ghost.

I certainly understand the argument: "Who cares about an extinct rat?" but you have no idea what role that rat plays in that functioning ecosystem. People can appreciate beauty, so that's why people love pandas and want to keep them around. You never hear, "What good is panda?" Ecologically, these rats are much more important to their ecosystem than those pandas— not that I don't love pandas but we have to look beyond the big and beautiful.

    I teach conservation biology and evolution. In both you have to appeal to people asking "Why is this important to me?" Some scientists refuse to do that. That's my entire approach. I'll ask "How many of you had a family member who was in a tornado, hurricane or flood?" .And almost every hand goes up. Climate change is suddenly very personal, and now they want to hear what you are saying. You are not looking for sympathy for the rats but for a greater understanding of the system.

    Students perform less well in final exams if smartphones are allowed in class, for non-academic (非学业的) purposes in lectures, a new study in Educational Psychology finds. Students who don't use smartphones themselves but attend lectures where their use is acceptable also do worse, suggesting that smartphone use damages the group learning environment.

    Researchers from Rutgers University in the US performed an in-class experiment to lest whether dividing attention between smartphones and the lecturer during the class affected students' performance in within-lecture tests and a final exam. 118 students at Rutgers University took part in the experiment during one term of their course. Smartphones were not allowed in half of the lectures and allowed in the other half. When smartphones were allowed, students were asked to record whether they had used them for non-academic purposes during the lecture.

    The study found that having a smartphone didn't lower students' scores in comprehension tests within lectures, but it did lower scores in the final exam by at least 5%, or half a grade. This finding shows for the first time that the main effect of divided attention in the classroom is on the length of time in keeping memory, with fewer things of a study task later remembered. In addition, when the use of smartphones was allowed in class, performance was also poorer for students who did not use them as well as for those who did.

    The study's lead author, Professor Arnold Glass, added: "These findings should alarm students and teachers that dividing attention is having a not obvious but harmful effect that is damaging their exam performance and final grade. To help manage the use of smartphones in the classroom, teachers should explain to students the alarming effect—not only for themselves, but for the whole class."

    This is the first-ever study in an actual classroom showing a relationship between losing attention from smartphones and exam performance. However, more researches are required to see how students are affected by using smartphones after school.

    The idea behind Facebook is to make us feel connected all the time. But in my research, I've found that the truth is quiet different.

    Technology, it turns out, has made being alone seem like a problem that needs soling. When young people are alone, even for a minute or two, they feel the need to connect to get on Facebook or some other social networks and chat. But in connecting, they often end up feeling more isolated. Why? Because by being in constant (不断的) connection, they lose the ability to feel satisfied with their own company (独处).

    Facebook can help us keep in touch with our friends, but we too often use it instead of spending face to face time with them. And since we feel the need to keep up with them online, we don't have moments of loneliness where we can collect our thoughts and learn how to be comfortable being alone.

——Sherry Turkle, Profescer

    Facebook connects more of us to more of our friends and family in more places than we have ever been connected before. Yes. Facebook is a huge time sink -maybe the biggest ever. Many people post useless stuff. And seeing too much of your friends lives can make you jealous (嫉妒的), but it won't make you lonely.

    Jane, a former student of mine, who is back in New York after living abroad for ten years told me that Facebook helps her a lot. The first time she moved back to New York from abroad, she felt disconnected from her family and friends. now because of lots of photos and information updates (更新), she knows what is happening with her friends all the time.

    In fact, if you are lonely in real life, you will be lonely online as well.

——Sree Steniveasan, Chief Digital office