At one time, computers were expected largely to remove the need for paper copies of documents(文件) because they could be stored electronically. But for all the texts that are written, stored and sent electronically, a lot of them are still ending up on paper.

    It is difficult to measure the quantity of paper used as a result of use of Internet-connected computers, although just about anyone who works in an office can tell you that when e-mail is introduced, the printers start working overtime. “I feel in my bones this revolution is causing more trees to be cut down,” says Ted Smith of the Earth Village Organization.

    Perhaps the best sign of how computer and Internet use pushes up demand for paper comes from the high-tech industry itself, which sees printing as one of its most promising new markets. Several Internet companies have been set up to help small businesses print quality documents from a computer. Earlier this week Hewlett-Packard Co. announced a plan to develop new technologies that will enable people to print even more so they can get a hard copy of a business document, a medical record or just a on-line e-mail, even if they are nowhere near a computer. As the company sees it, the more use of the Internet the greater demand for printers.

    Does all this mean environmental concerns (环境问题) have been forgotten? Some activists suggest people have been led to believe that a lot of dangers to the environment have gone away.

    “I guess people believe that the problem is taken care of, because of recycling（回收利用）,” said Kelly Quirke, director of the Rainforest Action Network in San Francisco. Yet Quirke is hopeful that high-tech may also prove helpful. He says printers that print on both sides are growing in popularity.

    The action group has also found acceptable paper made from materials other than wood, such as agricultural waste.

    After years of debate, gray wolves were reintroduced (重新引进) to Yellowstone National Park. Fourteen wolves were caught in Canada and moved to the park. By 2016, the Yellowstone wolf population had grown to more than 170.

    Gray wolves once were seen here and there in the Yellowstone area and other pans of United States, but they were gradually displaced by human development. By the 1920s, wolves had disappeared from the Yellowstone area. They went farther north into the deep forests of Canada, where there were fewer humans around. The disappearance of the wolves had many unexpected results. Deer and elk populations—major food sources(来源) for the wolf—grew rapidly. These animals ate large amounts of plants, which reduced plant diversity(多样性) in the park. With the disappearance of gray wolves, coyote (草原狼) populations also grew quickly. The coyotes killed a great number of red foxes in the park, and completely drove away the park's beavers (河狸).

    As early as 1966, biologists asked the government to consider reintroducing wolves to Yellowstone Park. They hoped that wolves would be able to control the elk and coyote problems. Many framers were against the plan because they feared that wolves would kill their farm animals or pets.

    The government spent nearly 30 years thinking lip a plan to reintroduce the wolves. The U.S. Fish and Wildlife Service carefully monitors and manages the wolf packs in Yellowstone. Today, the debate continues over how well the gray wolf is fitting in at Yellowstone. Elk, deer, and coyote populations are down, while beavers and red foxes have made a comeback. The Yellowstone wolf project has been a valuable experiment to help biologists decide whether to reintroduce wolves to other parts of the country as well.

Internet time tied to teen depression(抑郁) symptoms

    Spending time online is normal behaviour for teenagers. But too much Internet use by teens —or too little, for that matter —might be related to depression, a new study finds.

    The findings, reported in the journal of Pediatrics, do not mean that the Internet is to blame. For one, teens in the study who spent no time online were also at increased risk of depression symptoms. Instead, the researchers say that both heavy Internet use, and non-use, could serve as signals that a teenager is having a hard time.

    For the study, Dr. Pierre-Andre Michaud and his colleagues at the University of Lausanne, Switzerland, surveyed 7,200 individuals aged 16 to 20 about their Internet use.

    Those who were online more than two hours per day were considered "heavy" Internet users, while those online anywhere from several times per week to two hours per day were considered "regular" users.

    The teenagers also answered a number of health-related questions, including some standard questions about "depressive tendencies" that gauge(判定) how often a person feels sad or hopeless. Compared with regular Internet users, the study found, kids who were heavy users or non-users were more likely to be depressed or very depressed.

    Among male teens, heavy users and non-users were both around one-third more likely to have a high depression score, compared to "regular" users. Among girls, heavy Internet users had an 86 percent greater chance of depression, while non-users had a 46 percent greater likelihood compared to regular users.

    That was with factors like family income and any chronic health problems taken into account.

    Since teenagers typically go online to contact with friends, the researchers speculate(推测) that those who are never online may be more socially isolated.

    I have three kids and a great husband and I'm enjoying a career that I find challenging and fun. To the outside world, this feels like" Success." But there is still a voice in my heart asking if this is who I truly am. Only in silence do I hear the self and wonder who that person might be.

    So I booked a trip to find out. I travelled, for the first time, without my husband or kids. I went to Iceland with a friend, who shares an appreciation for wilderness and silence.

    For six days, we were immersed(沉浸)in wild, raw scenery and real weather—a11 kinds of weather. Climbing a mountain against rain and returning to a tent for a simple meal reminds you how little you actually need. And how strong it feels to be uncomfortable sometimes.

    I found silence in Iceland, and time to consider the me outside of career and the me out—side of kids as I shared stories with strangers.

    When I stopped talking and just 1istened, I became more generous. I 1earned that choosing to be generous can create more space, more food and more warmth.

But I didn't really gain any better appreciation of what I want from life or my job. I suspect the anxiety that drove me to seek silence in Iceland was losing sight of my ability to choose gratitude and joy, and to be present in the challenges I set in my career and my family.

    I came home to noise, rush and love; with no less confusion on who I want to be. I know the answer isn't waiting out there on the top of a mountain in Iceland. The answer is in front of me with every step on my own life's path, and in every choice I make.

    Attitudes toward new technologies often fall along generational lines. That is, generally, younger people tend to outnumber older people in face of a technological shift.

    It is not always the case, though. When you look at attitudes toward driverless cars, there doesn't seem to be a clear generational divide. The public overall disagree on whether they'd like to use a driverless car. In a study last year, of all people surveyed, 48 percent said they wanted to ride in one, while 50 percent did not.

    The fact that attitudes toward self-driving cars appear to be so steady across generations suggests how transformative the shift to driverless cars could be. Not everyone wants a driverless car now——and no one can get one yet ——but among those who are open to them, every age group is similarly engaged.

    When it comes to driverless cars, differences in attitude are obvious based on factors not related to age. College graduates, for example, are particularly interested in driverless cars compared with those who have less education: 59 percent of college graduates said they would like to use a driverless car compared with 38 percent of those with a high-school diploma or less.

    Where a person lives matters, too. More people who lived in cities and suburbs said they wanted to try driverless car than those who lived in rural areas.

    While there's reason to believe that interest in self-driving cars is going up, a person's age will have little to do with how self-driving cars can become mainstream. Once driverless cars are actually available for sale, the early adopters will be the people who can afford to buy them.