英語長篇閱讀文章

　　對於語言學習者而言,閱讀是語言輸入的重要方式。閱讀策略是語言學習者為了提高閱讀理解而採取的技巧和方法。下面是小編帶來的，歡迎閱讀!

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　　科技與自然

　　Technology that imitates nature

　　Biomimetics: Engineers are increasingly taking a leaf out of nature's book when looking for solutions to design problems

　　AFTER taking his dog for a walk one day in the early 1940s, George de Mestral, a Swiss inventor, became curious about the seeds of the burdock plant that had attached themselves to his clothes and to the dog's fur. Under a microscope, he looked closely at the hook-and-loop system that the seeds have evolved to hitchhike on passing animals and aid pollination, and he realised that the same approach could be used to join other things together. The result was Velcr a product that was arguably more than three billion years in the making, since that is how long the natural mechanism that inspired it took to evolve.

　　Velcro is probably the most famous and certainly the most successful example of biological mimicry, or “biomimetics”. In fields from robotics to materials science, technologists are increasingly borrowing ideas from nature, and with good reason: nature's designs have, by definition, stood the test of time, so it would be foolish to ignore them. Yet transplanting natural designs into man-made technologies is still a hit-or-miss affair.

　　Engineers depend on biologists to discover interesting mechanisms for them to exploit, says Julian Vincent, the director of the Centre for Biomimetic and Natural Technologies at the University of Bath in England. So he and his colleagues have been working on a scheme to enable engineers to bypass the biologists and tap into nature's ingenuity directly, via a database of “biological patents”. The idea is that this database will let anyone search through a wide range of biological mechanisms and properties to find natural solutions to technological problems.

　　How not to reinvent the wheel

　　Surely human intellect, and the deliberate application of design knowledge, can devise better mechanisms than the mindless, random process of evolution? Far from it. Over billions of years of trial and error, nature has devised effective solutions to all sorts of complicated real-world problems. Take the slippery task of controlling a submersible vehicle, for example. Using propellers, it is incredibly difficult to make refined movements. But Nekton Research, a company based in Durham, North Carolina, has developed a robot fish called Madeleine that manoeuvres using fins instead.

　　In some cases, engineers can spend decades inventing and perfecting a new technology, only to discover that nature beat them to it. The Venus flower basket, for example, a kind of deep-sea sponge, has spiny skeletal outgrowths that are remarkably similar, both in appearance and optical properties, to commercial optical fibres, notes Joanna Aizenberg, a researcher at Lucent Technology's Bell Laboratories in New Jersey. And sometimes the systems found in nature can make even the most advanced technologies look primitive by comparison, she says.

　　The skeletons of brittlestars, which are sea creatures related to starfish and sea urchins, contain thousands of tiny lenses that collectively form a single, distributed eye. This enables brittlestars to escape predators and distinguish between night and day. Besides having unusual optical properties and being very small—each is just one-twentieth of a millimetre in diameter—the lenses have another trick of particular relevance to micro-optical systems. Although the lenses are fixed in shape, they are connected via a network of fluid-filled channels, containing a light-absorbing pigment. The creature can vary the contrast of the lenses by controlling this fluid. The same idea can be applied in man-made lenses, says Dr Aizenberg. “These are made from silicon and so cannot change their properties,” she says. But by copying the brittlestar's fluidic system, she has been able to make biomimetic lens arrays with the same flexibility.

　　Another demonstration of the power of biomimetics comes from the gecko. This lizard's ability to walk up walls and along ceilings is of much interest, and not only to fans of Spider-Man. Two groups of researchers, one led by Andre Geim at Manchester University and the other by Ron Fearing at the University of California, Berkeley, have independently developed ways to copy the gecko's ability to cling to walls. The secret of the gecko's success lies in the tiny hair-like structures, called setae, that cover its feet. Instead of secreting a sticky substance, as you might expect, they owe their adhesive properties to incredibly weak intermolecular attractive forces. These van der Waals forces, as they are known, which exist between any two adjacent objects, arise between the setae and the wall to which the gecko is clinging. Normally such forces are negligible, but the setae, with their spatula-like tips, maximise the surface area in contact with the wall. The weak forces, multiplied across thousands of setae, are then sufficient to hold the lizard's weight.

　　Both the British and American teams have shown that the intricate design of these microscopic setae can be reproduced using synthetic materials. Dr Geim calls the result “gecko tape”. The technology is still some years away from commercialisation, says Thomas Kenny of Stanford University, who is a member of Dr Fearing's group. But when it does reach the market, rather than being used to make wall-crawling gloves, it will probably be used as an alternative to Velcro, or in sticking plasters. Indeed, says Dr Kenny, it could be particularly useful in medical applications where chemical adhesives cannot be used.

　　While it is far from obvious that geckos' feet could inspire a new kind of sticking plaster, there are some fields—such as robotics—in which borrowing designs from nature is self-evidently the sensible thing to do. The next generation of planetary exploration vehicles being designed by America's space agency, NASA, for example, will have legs rather than wheels. That is because legs can get you places that wheels cannot, says Dr Kenny. Wheels work well on flat surfaces, but are much less efficient on uneven terrain. Scientists at NASA's Ames Research Centre in Mountain View, California, are evaluating an eight-legged walking robot modelled on a scorpion, and America's Defence Advanced Research Projects Agency DARPA is funding research into four-legged robot dogs, with a view to applying the technology on the battlefield.

　　Having legs is only half the story—it's how you control them that counts, says Joseph Ayers, a biologist and neurophysiologist at Northeastern University, Massachusetts. He has spent recent years developing a biomimetic robotic lobster that does not just look like a lobster but actually emulates parts of a lobster's nervous system to control its walking behaviour. The control system of the scorpion robot, which is being developed by NASA in conjunction with the University of Bremen in Germany, is also biologically inspired. Meanwhile, a Finnish technology firm, Plustech, has developed a six-legged tractor for use in forestry. Clambering over fallen logs and up steep hills, it can cross terrain that would be impassable in a wheeled vehicle.

　　Other examples of biomimetics abound: Autotype, a materials firm, has developed a plastic film based on the complex microstructures found in moth eyes, which have evolved to collect as much light as possible without reflection. When applied to the screen of a mobile phone, the film reduces reflections and improves readability, and improves battery life since there is less need to illuminate the screen. Researchers at the University of Florida, meanwhile, have devised a coating inspired by the rough, bristly skin of sharks. It can be applied to the hulls of ships and submarines to prevent algae and barnacles from attaching themselves. At Penn State University, engineers have designed aircraft wings that can change shape in different phases of flight, just as birds' wings do. And Dr Vincent has devised a smart fabric, inspired by the way in which pine cones open and close depending on the humidity, that could be used to make clothing that adjusts to changing body temperatures and keeps the wearer cool.

　　From hit-and-miss to point-and-click

　　Yet despite all these successes, biomimetics still depends far too heavily on serendipity, says Dr Vincent. He estimates that there is only a 10% overlap between biological and technological mechanisms used to solve particular problems. In other words, there is still an enormous number of potentially useful mechanisms that have yet to be exploited. The problem is that the engineers looking for solutions depend on biologists having already found them—and the two groups move in different circles and speak very different languages. A natural mechanism or property must first be discovered by biologists, described in technological terms, and then picked up by an engineer who recognises its potential.

　　This process is entirely the wrong way round, says Dr Vincent. “To be effective, biomimetics should be providing examples of suitable technologies from biology which fulfil the requirements of a particular engineering problem,” he explains. That is why he and his colleagues, with funding from Britain's Engineering and Physical Sciences Research Council, have spent the past three years building a database of biological tricks which engineers will be able to access to find natural solutions to their design problems. A search of the database with the keyword “propulsion”, for example, produces a range of propulsion mechanisms used by jellyfish, frogs and crustaceans.

　　The database can also be queried using a technique developed in Russia, known as the theory of inventive problem solving, or TRIZ. In essence, this is a set of rules that breaks down a problem into smaller parts, and those parts into particular functions that must be performed by components of the solution. Usually these functions are compared against a database of engineering patents, but Dr Vincent's team have substituted their database of “biological patents” instead. These are not patents in the conventional sense, of course, since the information will be available for use by anyone. By calling biomimetic tricks “biological patents”, the researchers are just emphasising that nature is, in effect, the patent holder.

　　One way to use the system is to characterise an engineering problem in the form of a list of desirable features that the solution ought to have, and another list of undesirable features that it ought to avoid. The database is then searched for any biological patents that meet those criteria. So, for example, searching for a means of defying gravity might produce a number of possible solutions taken from different flying creatures but described in engineering terms. “If you want flight, you don't copy a bird, but you do copy the use of wings and aerofoils,” says Dr Vincent.

　　He hopes that the database will store more than just blueprints for biological mechanisms that can be replicated using technology. Biomimetics can help with software, as well as hardware, as the robolobster built by Dr Ayers demonstrates. Its physical design and control systems are both biologically inspired. Most current robots, in contrast, are deterministically programmed. When building a robot, the designers must anticipate every contingency of the robot's environment and tell it how to respond in each case. Animal models, however, provide a plethora of proven solutions to real-world problems that could be useful in all sorts of applications. “The set of behavioural acts that a lobster goes through when searching for food is exactly what one would want a robot to do to search for underwater mines,” says Dr Ayers. It took nature millions of years of trial and error to evolve these behaviours, he says, so it would be silly not to take advantage of them.

　　Although Dr Vincent's database will not be capable of providing such specific results as control algorithms, it could help to identify natural systems and behaviours that might be useful to engineers. But it is still early days. So far the database contains only 2,500 patents. To make it really useful, Dr Vincent wants to collect ten times as many, a task for which he intends to ask the online community for help. Building a repository of nature's cleverest designs, he hopes, will eventually make it easier and quicker for engineers to steal and reuse them.

　　2　　Lessons from a feminist paradise on Equal Pay Day

　　On the surface, Sweden appears to be a feminist paradise. Look at any global survey of gender equity and Sweden will be near the top. Family-friendly policies are its norm — with 16 months of paid parental leave, special protections for part-time workers, and state-subsidized preschools where, according to a government website, “gender-awareness education is increasingly common.” Due to an unofficial quota system, women hold 45 percent of positions in the Swedish parliament. They have enjoyed the protection of government agencies with titles like the Ministry of Integration and Gender Equality and the Secretariat of Gender Research. So why are American women so far ahead of their Swedish counterparts in breaking through the glass ceiling?

　　In a 2012 report, the World Economic Forum found that when it comes to closing the gender gap in “economic participation and opportunity,” the United States is ahead of not only Sweden but also Finland, Denmark, the Netherlands, Iceland, Germany, and the United Kingdom. Sweden’s rank in the report can largely be explained by its political quota system. Though the United States has fewer women in the workforce 68 percent compared to Sweden’s 77 percent, American women who choose to be employed are far more likely to work full-time and to hold high-level jobs as managers or professionals. Compared to their European counterparts, they own more businesses, launch more start start-ups, and more often work in traditionally male fields. As for breaking the glass ceiling in business, American women are well in the lead, as the chart below shows.

　　What explains the American advantage? How can it be that societies like Sweden, where gender equity is relentlessly pursued and enforced, have fewer female managers, executives, professionals, and business owners than the laissez-faire United States? A new study by Cornell economists Francine Blau and Lawrence Kahn gives an explanation.

　　Generous parental leave policies and readily available part-time options have unintended consequences: instead of strengthening women’s attachment to the workplace, they appear to weaken it. In addition to a 16-month leave, a Swedish parent has the right to work six hours a day for a reduced salary until his or her child is eight years old. Mothers are far more likely than fathers to take advantage of this law. But extended leaves and part-time employment are known to be harmful to careers — for both genders. And with women a second factor comes into play: most seem to enjoy the flex-time arrangement once known as the “mommy track” and never find their way back to full-time or high-level employment. In sum: generous family-friendly policies do keep more women in the labor market, but they also tend to diminish their careers.

　　According to Blau and Kahn, Swedish-style paternal leave policies and flex-time arrangements pose a second threat to women’s progress: they make employers wary of hiring women for full-time positions at all. Offering a job to a man is the safer bet. He is far less likely to take a year of parental leave and then return on a reduced work schedule for the next eight years.

　　I became aware of the trials of career-focused European women a few years ago when I met a post-doctoral student from Germany who was then a visiting fellow at Johns Hopkins. She was astonished by the professional possibilities afforded to young American women. Her best hope in Germany was a government job –– prospects for women in the private sector were dim. “In Germany,” she told me, “we have all the benefits, but employers don’t want to hire us.”

　　Swedish economists Magnus Henrekson and Mikael Stenkula addressed the following question in their 2009 study: why are there so few female top executives in the European egalitarian welfare states? Their answer: “Broad-based welfare-state policies impede women’s representation in elite competitive positions.”

　　It is tempting to declare the Swedish policies regressive and hail the American system as superior. But that would be shortsighted. The Swedes can certainly take a lesson from the United States and look for ways to clear a path for their high-octane female careerists. But most women are not committed careerists. When the Pew Research Center recently asked American parents to identify their "ideal" life arrangement, 47 percent of mothers said they would prefer to work part-time and 20 percent said they would prefer not to work at all. Fathers answered differently: 75 percent preferred full-time work. Some version of the Swedish system might work well for a majority of American parents, but the United States is unlikely to fully embrace the Swedish model. Still, we can learn from their experience.

　　Despite its failure to shatter the glass ceiling, Sweden has one of the most powerful and innovative economies in the world. In its 2011-2012 survey, the World Economic Forum ranked Sweden as the world’s third most competitive economy; the United States came in fifth. Sweden, dubbed the "rockstar of the recovery" in the Washington Post, also leads the world in life satisfaction and happiness. It is a society well worth studying, and its efforts to conquer the gender gap impart a vital lesson — though not the lesson the Swedes had in mind.

　　Sweden has gone farther than any nation on earth to integrate the sexes and to offer women the same opportunities and freedoms as men. For decades, these descendants of the Vikings have been trying to show the world that the right mix of enlightened policy, consciousness raising, and non-sexist child rearing would close the gender divide once and for all. Yet the divide persists.

　　A 2012 press release from Statistics Sweden bears the title “Gender Equality in Sweden Treading Water” and notes:

　　The total income from employment for all ages is lower for women than for men.

　　One in three employed women and one in ten employed men work part-time.

　　Women’s working time is influenced by the number and age of their children, but men’s working time is not affected by these factors.

　　Of all employees, only 13 percent of the women and 12 percent of the men have occupations with an even distribution of the sexes.

　　Confronted with such facts, some Swedish activists and legislators are demanding more extreme and far-reaching measures, such as replacing male and female pronouns with a neutral alternative and monitoring children more closely to correct them when they gravitate toward gendered play. When it came to light last year that mothers, far more than fathers, chose to stay home from work to care for their sick toddlers, Ulf Kristersson, minister of social security, quickly commissioned a study to determine the causes of and possible cures for this disturbing state of affairs.

　　I have another suggestion for Kristersson and his compatriots: acknowledge the results of your own 40-year experiment. The sexes are not interchangeable. When Catherine Hakim, a sociologist at the London School of Economics, studied the preferences of women and men in Western Europe, her results matched those of the aforementioned Pew study. Women, far more than men, give priority to domestic life. The Swedes should consider the possibility that the current division of labor is not an artifact of sexism, but the triumph of liberated preference.

　　In the 1940s, the American playwright, congresswoman, and conservative feminist Clare Boothe Luce made a prediction about what would happen to men and women under conditions of freedom:

　　It is time to leave the question of the role of women in society up to Mother Nature — a difficult lady to fool. You have only to give women the same opportunities as men, and you will soon find out what is or is not in their nature. What is in women’s nature to do they will do, and you won’t be able to stop them. But you will also find, and so will they, that what is not in their nature, even if they are given every opportunity, they will not do, and you won’t be able to make them do it.

　　In Luce’s day, sex-role stereotypes still powerfully limited women’s choices. More than half a century later, women in the Western democracies enjoy the equality of opportunity of which she spoke. Nowhere is this more true than Sweden. And although it was not the Swedes’ intention, they have demonstrated to the world what the sexes will and will not do when offered the same opportunities.

　　Today is Equal Pay Day. But as most feminists know by now, the wage gap is largely the result of women’s vocational choices and how they prefer to balance home and family. To close the gap, it won’t be enough to change society or reform the workplace –– it is women’s elemental preferences that will have to change. But look to Sweden: women’s preferences remain the same.

　　Not only feminists, but also liberal and conservative policymakers should pay attention. Sweden is not the “tax and spend” welfare state of old –– while the rest of the world is floundering in debt, Sweden along with its Nordic neighbors has been downsizing, reforming entitlements, and balancing its books. The budget deficit in Sweden is about 0.2 percent of its GDP; in the United States, it’s 7 percent. But Sweden’s generous family-friendly policies remain in place. The practical, problem-solving Swedes have judged them to be a good investment. They may be right.

　　Swedish family policies, by accommodating women’s preferences so effectively, are reducing the number of women in elite competitive positions. The Swedes will find this paradoxical and try to find solutions. Let us hope these do not include banning gender pronouns, policing children’s play, implementing more gender quotas, or treating women’s special attachment to home and family as a social injustice. Most mothers do not aspire to elite, competitive full-time positions: the Swedish policies have given them the freedom and opportunity to live the lives they prefer. Americans should look past the gender rhetoric and consider what these Scandinavians have achieved. On their way to creating a feminist paradise, the Swedes have inadvertently created a haven for normal mortals.

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　　科學家告訴你：這樣學才記得牢

　　The older we get, the harder it seems to remember names, dates, facts of all kinds. It takes longer to retrieve the information we want, and it often pops right up a few minutes or hours later when we are thinking about something else. The experts say that keeping your mind sharp with games like Sudoku and crossword puzzles slows the aging process, and that may be true, but we found three other things you can do to sharpen your memory.

　　隨著年齡的增長，我們似乎越來越記不住人名、日期、還有各種事情。我們要花更多的時間搜尋腦內的資訊，而這些資訊往往在我們開始想別的事情的時候突然湧出腦海。專家認為經常玩數獨遊戲和填字遊戲可以減緩腦部衰老的過程。這也許可行，但是我們還發現了另外三種方式來提升記憶力。

　　1. Vary Your Study Space

　　1. 更換學習場所

　　A study shows students who studied a list of words in a windowless room and again in a room with a view did far better on a test than students who studied only in the room without a view.

　　研究表明，先在一間無窗教室裡學習單詞後搬到有窗教室的學生要比一直在無窗教室裡學習並且欣賞不到風景的學生掌握得更好。

　　Dr. Robert A. Bjork, psychologist at the University of California, L.A. and senior author of the research, states, “What we think is happening here is that, when the outside context is varied, the information is enriched, and this slows down forgetting.”

　　加利福尼亞大學洛杉磯分校的心理學家羅伯特·A·比約克博士稱，“我們認為之所以會產生這種結果，是因為外部環境改變時，學生獲得的資訊變豐富了，這就減緩了遺忘的過程。”

　　2. Vary What You Study

　　2. 更換學習內容

　　The same principal may apply to what you study. Musicians and athletes have known this for years. They practice cross-training.

　　相同的原理可以用在學習內容上，多年前音樂家和運動員就已經知道這個道理了。他們採用交叉培訓的方式來練習。

　　“Varying the type of material studied in a single sitting — alternating, for example, among vocabulary, reading and speaking in a new language — seems to leave a deeper impression on the brain than does concentrating on just one skill at a time,” Carey writes.

　　凱利在其研究中寫道，“在同一段時間裡學習不同類別的內容，比如，學習一門新語言時可以在詞彙、閱讀、口語等不同技能間轉換，這樣比單單學習一種技能在大腦裡留下的印象更深。”

　　It might also be helpful, and this is my advice, to vary your learning style. Most of us use more than one style anyway, but if you find yourself relying primarily on visual learning, try auditory or kinesthetic techniques. You might be surprised.

　　我給出的另一個也許有用的建議是，改變學習方式。大多數人都會採用不止一種的學習方式，但是，如果你發現自己主要採用視覺學習，可以試著加上聽覺或者肌肉運動知覺，效果也許很驚豔。

　　3. Test Yourself Often

　　3. 經常檢測自己

　　It also turns out that when a student is required to retrieve information, say for a test, that information is re-stored in the brain in a more accessible way for future use.

　　事實證明，當一個學生被要求在腦內搜尋一個資訊，比如考試，那麼這些資訊就會被儲存在大腦裡，供其今後更方便地使用。

　　Carey reports that researchers don’t know why this is true, just that it is.“It may be that the brain, when it revisits material at a later time, has to relearn some of what it has absorbed before adding new stuff — and that that process is itself self-reinforcing,” he writes.

　　凱利表示，研究者們不理解為什麼會這樣，但事實確實如此。他寫道，“也許是大腦在後來重新回憶這些內容的時候，在新加上一些內容前，需要重新回顧之前吸收的內容，這樣的過程就相當於大腦的自我強化。”

　　“The idea is that forgetting is the friend of learning,” Carey quotes Dr. Nate Kornell, a psychologist at Williams College, as saying. “When you forget something, it allows you to relearn, and do so effectively.”Practice tests, then, are powerful learning tools.

　　凱利引用威廉姆斯學院心理學家奈特·科內爾博士的一段話，稱“遺忘伴隨著學習。遺忘使你重新學習某件事，並能更高效地學習。”那麼，不斷測試自己就成了有用的學習工具。