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Electric BackpackBackpacks are convenient. They can hold your books, your lunch, and a change of clothes, leaving your hands free to do other things. Someday, if you don"t mind carrying a heavy load, your backpacks might also power your MP3 player, keep your cell phone running, and maybe even light your way home.Lawrence C. Rome and his colleagues from the University of Pennsylvania in Philadelphia have invented a backpack that makes electricity from energy produced while its wearer walks. In military actions, search-and-rescue operations, and scientific field studies, people rely increasingly on cell phones, global positioning system (GPS) receivers (接收器), night-vision goggles (夜视镜), and other battery-powered devices to get around and do their work. The backpack"s electricity-generating feature could greatly reduce the amount of a wearer"s load now devoted to spare batteries.The backpack"s electricity-creating powers depend onspringsused to hang a cloth pack from its metal frame. The whole pack moves up and down as the person walks. A special mechanism converts movements of the pack to electricity, which can be as much as 7.4 watts.Unexpectedly, tests showed that wearers of the new backpack alter their gaits (步法) in response to the pack"s oscillations (摆动), so that they carry loads more comfortably and with less effort than they do ordinary backpacks. Because of that surprising advantage, Rome plans to commercialize both electric and nonelectric versions of the backpack.The backpack could be especially useful for soldiers, scientists, mountaineers (登山运动员), and emergency workers who typically carry heavy backpacks. For the rest of us, power-generating backpacks could make it possible to walk, play video games, watch TV, and listen to music, all at the same time. Electricity-generating packs aren"t on the market yet, but if you do get one eventually, just make sure to look both ways before crossing the street! Backpacks are very convenient because they can ______.
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Covering the Cost All by HimselfUniversity life is in no way cheap in Canada. It costs Peter Kemp, a computer science major at the British Columbia Institute of Technology in Vancouver, C $18,000 a year. Amazingly, the 21-year-old is covering the cost by himself.For the past three years, Kemp has done a range of part-time jobs to pay for his tuition and living expenses. Last semester alone, he worked five jobs for 32-40 hours a week. Life is busy, but Kemp enjoys it."Doing part-time jobs gives me economic independence," said Kemp, who will begin his senior year this fall. "Having economic independence gives me the ability to take control of my life and make my own decisions," said Kemp. "It has also helped me understand the value of money."Among Kemp"s five jobs last semester, two were on campus. For one, he helped maintain the university"s computer labs. For the other, he worked at the IT service desk to help students and teachers solve their computer problems. He also worked for a small company that develops GPS systems. This job paid him well at C $27 an hour."These jobs made me put what I"ve learned in university to practical use," Kemp said. "I accomplished creative and imaginative tasks by applying my abilities to the work."Good time management skills help Kemp balance work and study. He"s a top student in his class. And he will be the student association chairman for his department beginning next semester. It"s a position that he has desired for a long time. "It will give me the opportunity to be the voice for my fellow students and make a difference," says Kemp."I believe one of the key secrets to juggling (应对) everything is to avoidputting offtasks. This can leave you stressed and reduce the quality of your work and health," he said."I often make a list of the things I need to do each day and rank them by their importance. The list helps me decide what task I should do first and when I should complete it. Remember to ask for help when you think you can"t finish something on time, or can"t finish it by yourself." How did he manage to pay his tuition and living expenses
Time to Stop Traveling by AirTwenty-five years ago a young British man called Mark Ellingham decided that he wanted a change of scenery. So he went to Australia, stopping off in many countries in between. He also decided to write about the experience and produced a guide for other travelers making similar journeys.In 1970, British airports were used by 32 million people. In 2004, the figure was 216 million. In 2030, according to government forecasts, it will be around 500 million. It"s a growth driven by the emergence of low cost airlines, offering access to all parts of the world for less than ￡100.This has made a huge contribution to global warming. One return flight from Britain to the US produces the same carbon dioxide (二氧化碳) as a year"s motoring (驾车). A return flight to Australia equals the emissions (排放) of three average cars for a year. And the pollution is released at a height where its effect on climate change is more than double that on the ground.Mark Ellingham built his business on helping people travel. Now he wants to help people stop—at least by air.He is calling for a ￡100 green tax on all flights to Europe and Africa, and ￡250 on flights to the rest of the world. He also wants investment to create a low-carbon economy, as well as a halt to airport expansion.Mark Ellingham"s commitment is important because his readers aren"t just the sort of young and adventurous people who would happily jump on a plane to spend a weekend exploring a foreign culture. They are also the sort of people who say they care about the environment. It"s a debate that splits people down the middle.The tourist industry has responded by offering offsetting (补偿) schemes. A small increase in the price of a ticket is used to plant trees.But critics say that it is not enough to just be carbon neutral. We should be actively cutting back on putting greenhouse gases into the atmosphere. And for the average person, making a plane journey will be his or her largest contribution to global warming. It may be good to repair the damage we do. But surely it is better not to do the damage in the first place. Mark Ellingham has never hesitated to encourage people to travel by air.
Covering the Cost All by HimselfUniversity life is in no way cheap in Canada. It costs Peter Kemp, a computer science major at the British Columbia Institute of Technology in Vancouver, C $18,000 a year. Amazingly, the 21-year-old is covering the cost by himself.For the past three years, Kemp has done a range of part-time jobs to pay for his tuition and living expenses. Last semester alone, he worked five jobs for 32-40 hours a week. Life is busy, but Kemp enjoys it."Doing part-time jobs gives me economic independence," said Kemp, who will begin his senior year this fall. "Having economic independence gives me the ability to take control of my life and make my own decisions," said Kemp. "It has also helped me understand the value of money."Among Kemp"s five jobs last semester, two were on campus. For one, he helped maintain the university"s computer labs. For the other, he worked at the IT service desk to help students and teachers solve their computer problems. He also worked for a small company that develops GPS systems. This job paid him well at C $27 an hour."These jobs made me put what I"ve learned in university to practical use," Kemp said. "I accomplished creative and imaginative tasks by applying my abilities to the work."Good time management skills help Kemp balance work and study. He"s a top student in his class. And he will be the student association chairman for his department beginning next semester. It"s a position that he has desired for a long time. "It will give me the opportunity to be the voice for my fellow students and make a difference," says Kemp."I believe one of the key secrets to juggling (应对) everything is to avoidputting offtasks. This can leave you stressed and reduce the quality of your work and health," he said."I often make a list of the things I need to do each day and rank them by their importance. The list helps me decide what task I should do first and when I should complete it. Remember to ask for help when you think you can"t finish something on time, or can"t finish it by yourself." Kemp is able to balance work and study due to his ______.
Feed the World with Potatoes1 As food prices continue to rise rapidly, there is growing concern about the effect it will have among the world"s poor.2 Increasingly, experts are looking to the potato as a possible low-cost solution to feeding the hungry. To emphasize the issue, the United Nations has called the potato "a hidden treasure", and named 2008 the International Year of the Potato. Here"s how potatoes could end the food crisis.3 The potato matures more quickly, on less land and in harsher climates than most other major crops. Up to 85 percent of the plant is eatable, compared with around 50 percent of cereals. Its broad adaptability to a wide variety of farming systems is also noteworthy.4 Potatoes are an excellent source of complex carbohydrates ( 碳水化合物), which release their energy slowly, and have only 5 percent of wheat"s fat content. They contain only a quarter of the calories of bread and, according to the Potato Center, when boiled, potatoes have more protein and nearly twice the calcium (钙) as corn. Additionally, they are good sources of vitamin C, iron, potassium (钾) and zinc (锌).5 The Food and Agricultural Organization recently surveyed food price inflation in over 70 of the poor countries. Cereal price inflation was much higher and far more widespread than for potatoes. A significant factor behind the potato"s affordability is the fact that unlike other agricultural products, the potato is not yet a global commodity, and has therefore not attracted speculative investors. Raw potatoes are heavy and can rot during transit, so global trade has been slow to take off. Also, potatoes are susceptible (易受影响的) to infection with disease, hindering (阻碍) export. According to analysts" estimates, less than 5 percent of potatoes are traded internationally, with prices driven primarily by local tastes instead of international demand. The potato is not yet a global commodity because ______.
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