"Iris scan (虹膜扫描), please," the bank's computer voice tells you . You step up and the computer reads your eye, comparing it to the stored file it has of your iris. The images had better match—otherwise you won't be able to get your money.

    Iris scanning and other technologies, such as fingerprint and voice scanning, have appeared in many science fiction movies in the past. Today, these advanced technologies are part of the real world. They are common at work, the bank, the airport, and your local prison. The iris scan, fingerprint scan, and voice scan are all examples of biometrics( 生物测定学) a fast developing area of automatic personal identification technology . Basically, biometrics uses various ways to verify a person's identity, based on the individual's unique characteristics, including fingerprints, voices, irises, body heat patterns, facial images, handprints, signatures and so on.

    Biometrics identification systems have a number of advantages over password systems. The primary advantage is that an individual has to be physically present in order to be identified. Another important advantage is that there are no passwords to remember, forget, lose or steal.

    The voice scan is the simplest and most affordable form of biometrics. It only requires a computer, a microphone and the correct software. The software records a subject's voice and then compares it to a stored voice sample for identification purposes.

    For additional safety, fingerprint and handprint scans can also be employed. Fingerprint scans take the image of a fingerprint and compare it to a stored file of prints. Handprint scans identify the unique features of a hand.

    Iris scans currently give the highest level of accuracy among all the available biometrics systems. Another technology, full facial scans, is currently in use at border crossings and airports. Facial scanning equipment can actually track and identify moving faces within a crowd.

    The potential of biometrics is exciting and encouraging. With continued development, testing, and application, current technologies will become even more effective in the future. Soon, the days of password and car keys will be gone. Just don't leave home without your fingerprints!

    Chicago is considering firm measures to prevent the Asian carp, a giant fish native to the Far East, from coming into North America's Great Lakes in large numbers. Such a move could cost up to$18bn, a heavy economic burden to the city.

    This species, more than a metre in length, was originally introduced to southern US states three decades ago to control weeds in sewage (污水) treatment plants. But they escaped into the Mississippi River and increased in number quickly, making their way north towards the Great Lakes and threatening the native fish species along the way.

    "Dozens of them will often leap out of the water as boats approach." Michael Beecham, a local environmental expert, described how frightening the scene was. "I've gone down the river and seen these fish jump up and hit me in the face. It is a big problem for our native species." he said.

    A meeting has been organized to find a technological solution to the carp problem, one of which involves blocking parts of Chicago's canal system. Listening at the meeting was John Goss, who was worried about the effect that having barriers in the canal system would have on industry. "It would certainly increase the cost of transportation," he told. "It is currently very cheap and efficient to bring materials and finished goods down the Chicago ship canal.''

    Another cheaper option is to eat the fish out of existence. Dirk Fucik is selling carp burger(鲤鱼汉堡包) at his fish shop not far from downtown Chicago. He thinks the carps are a great resource. "To catch it and throw it away is a waste," he says. "Eating them helps solve the problem and also provides jobs." But the idea has not yet caught on. So far, he is the only person in Chicago selling carp burgers.

    The ocean is filled with eight million tons of rubbish—enough to fill five carrier bags for every foot of coastline on the planet. But a new invention could deal with this problem, one port at a time.

    A pair of surfers from Perth, Australia, has invented a "floating bin" that automatically draws rubbish floating on the water into it like a vacuum (真空) cleaner. While the invention may do little to battle against five giant "garbage islands" that flow around the world's  major ocean gyres (环流), it could stop waste from leaving harbours and marinas, for example. Peter Ceglinski and Andrew Turton said their device could spell the end of polluted seas.

    The concept is simple: A bucket connects to a water pump, drawing in any floating trash inside a removable net bag. There is also an optional oil-water separator system inside the pump. It can remove oil from the seawater before spitting it back into the ocean — pollution-free — through the other side of the pump.

    The water filtration (过滤) system is much like what you'd find in a fish tank, but it has the potential to clean up an entire ocean. The seabin can run 24/7, according to its website. And, amazingly, Peter and Andrew say they have never caught a fish or sea animal in their pumps in four years of testing.

    The Seabin Project aims to improve on the traditional and sometimes expensive — harbor cleaning methods of having a person physically remove trash from the water or sending boats equipped with nets to collect it. While it's not as extensive as 21-year-old Boyan Slat's plan to clean the entire Pacific Ocean in 10 years, starting in 2020, the seabin's creators said their device is something that harbors can start using to clean our oceans now.

    They're starting "close to the source of the problem in a controlled environment," Seabin's website states. "It's a big mission, but it can be done. In fact, we're doing it right now."

    A campaign is being launched to encourage children to surrender 30 minutes of screen time a day to head for the great outdoors.

    The newly formed Wild Network—a collaboration of nearly 400 organizations—is attempting to attract youngsters away from television and computer screens to fields, woods and parks. Members of the network include the National Trust, RSPB, Play England and the NHS. Organizers say it is the UK's biggest ever campaign to reconnect children with nature and outdoor play, and claim it could help improve fitness, mental alertness and general well-being.

    A documentary film, Project Wild Thing, will forecast the launch at more than 50 cinemas across the UK from Friday. It looks at the increasing link between children and nature.

    Andy Simpson, chairman of the Wild Network, said, "The tragic truth is that kids have lost touch with nature and the outdoors in just one generation. Time spent outdoors is decreasing, roaming (漫步) ranges have fallen largely, activity levels are declining and the ability to identify common species has been lost."

    Suggestions on how to get more time in nature include collecting conkers (七叶树果), camping, snail racing, and observing autumn colour on trees.

    From January, the network will aim to make suggestions on how the government can do more to get children muddy and bright-eyed.

    This is not the first time the message of less screen time, more play has been brought up. Children in the 1980s were requested to do the same by the BBC TV series Why Don't You, which somewhat confusingly called on its viewers to "switch off the TV set and go to do something less boring instead".

    Humans are social animals. They live in groups all over the world. As these groups of people live apart from other groups, over the years and centuries they develop their own habits and ideas, which are different from other cultures. One important particular side of every culture is how its people deal with time.

    Time is not very important in nonindustrial (非工业的) societies. The Nuer people of East Africa, for example, do not even have a word TIME that is in agreement with the abstract thing we call time. The daily lives of the people of such nonindustrial societies are likely to be patterned around their physical needs and natural events rather than around a time schedule (时间表) based on the clock. They cook and eat when they are hungry and sleep when the sun goes down. They plant crops during the growing seasons and harvest them when the crops are ripe. They measure time not by a clock or calendar, but by saying that an event takes place before or after some other event. Frequently such a society measures days in terms of "sleeps" or longer periods in terms of "moons". Some cultures, such as the Eskimos of Greenland measure seasons according to the migration of certain animals.

    Some cultures which do not have a written language or keep written records have developed interesting ways of "telling time". For example, when several Australian aborigines want to plan an event for a future time, one of them places a stone on a cliff or in a tree. Each day the angle of the sun changes slightly. In a few days, the rays of the sun strike the stone in a certain way. When this happens, the people see that the agreed-upon time has arrived and the event can take place.

    In contrast (成对比), exactly correct measurement of time is very important in modern, industrialized societies.

    This is because industrialized societies require the helpful efforts of many people in order to work. For a factory to work efficiently (well, quickly and without waste), for example, all of the workers must work at the same time. Therefore, they must know what time to start work in the morning and what time they may go home in the afternoon. Passengers must know the exact time that an airplane will arrive or depart. Students and teachers need to know when a class starts and ends. Stores must open on time in order to serve their customers. Complicated (复杂的) societies need clocks and calendars. Thus, we can see that if each person worked according to his or her own schedule, a complicated society could hardly work at all.

Grizzly bears,which may grow to about 2.5 m long and weigh over 400 kg,occupy a conflicted corner of the American psyche—we revere(敬畏) them even as they give us frightening dreams.Ask the tourists from around the world that flood into Yellowstone National Park what they most hope to see,and their answer is often the same:a grizzly bear.

"Grizzly bears are re-occupying large areas of their former range,"says bear biologist Chris Servheen.As grizzly bears expand their range into places where they haven't been seen in a century or more,they're increasingly being sighted by humans.

The western half of the U.S.was full of grizzlies when Europeans came,with a rough number of 50,000 or more living alongside Native Americans.By the early 1970s,after centuries of cruel and continuous hunting by settlers,600 to 800 grizzlies remained on a mere 2 percent of their former range in the Northern Rockies.In 1975,grizzlies were listed under the Endangered Species Act.

Today,there are about 2,000 or more grizzly bears in the U.S.Their recovery has been so successful that the U.S.Fish and Wildlife Service has twice attempted to de-list grizzlies,which would loosen legal protections and allow them to be hunted.Both efforts were overturned due to lawsuits from conservation groups.For now,grizzlies remain listed.

Obviously,if precautions(预防) aren't taken,grizzlies can become troublesome,sometimes killing farm animals or walking through yards in search of food.If people remove food and attractants from their yards and campsites,grizzlies will typically pass by without trouble.Putting electric fencing around chicken houses and other farm animal quarters is also highly effective at getting grizzlies away."Our hope is to have a clean,attractant-free place where bears can pass through without learning bad habits,"says James Jonkel,longtime biologist who manages bears in and around Missoula.