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When Lewis Ziska wanted to see how a warmer wood with more carbon dioxide in the air would affect certain plants, he didn’t set up his experiment in a greenhouse or boot up a computer model. He headed for Baltimore. Cities are typically 7 degrees warmer than the countryside, as well as big sources of CO2. So Ziska, a plant physiologist at the U.S. Department of Agriculture, compa,ed ragweed growing in vacant lots in Baltimore with ragweed in rural fields—and discovered the dark side of sunny claims that global warming will produce a "greening of planet Earth". Urban ragweed grows three to five times bigger than rural ragweed, starts spewing allergenic pollen weeks earlier each spring and produces 10 times more pollen. In as few as 20 years the whole world will have CO2 levels at least as high as some cities do now. As climate changes due to the greenhouse effect, hayfever sufferers would do well to lay in copious supplies of Kleenex. From mosquitoes that carry tropical diseases such as malaria, to plants that produce allergenic pollen, scientists are finding that a warmer, CO2-rich world will be very, very. good for plants, insects and microbes that make us sick. Although the most obvious threat to human health is more frequent and more intense heat weaves, such as the one that killed thousands of people in Europe in 2003, that is only the beginning. In the case of plants, it’s not just that they grow faster and shed pollen earlier as the woad warms. The carbon-enriched air also alters their physiology. In a six-year study at a pine forest managed by Duke University, where pipes and fans adjust the CO2 concentration and the air, scientists found that elevated CO2 increases the growth rate of poison ivy. More surprising, by increasing the air’s ration of carbon to nitrogen, elevated CO2 also increases the toxicity of urushiol, the rash-causing oil. "Poison ivy will become not just more abundant in the future," says Ziska. "It will also be more toxic. " Plants interpret warmth and abundant CO2as: what a great climate for reproduction. Monitoring stations in Europe are recording higher pollen counts for allergenic grasses and trees, led by birch and hazel, notes a 2005 study by the Center for Health and the Global Environment at Harvard Medical School. Those counts are rising earlier each year: the warming already underway is shifting the pollen season by almost one day per year. By 2017, you’ll be reaching for tissues nine days sooner than you do now. More good news: in a greenhouse world po]len will be not only more abundant but more allergenic, he and Ziska find. Since cities already have the high CO2 levels that the rest of the world can soon expect, "’there is no question these climate-related changes have already begun," says Arlington, Texas, Mayo," Dr. Robert Cluck. "Every summner we’re seeing West Nile virus earlier and earlier, and the higher levels of ozone that come with higher temperatures are increasing the rates of asthma and causing heart and lung damage comparable to living with a cigarette smoker. " In a greenhouse world, tropical diseases will expand their range and their prevalence. For instance, alternating floods and droughts—the pattern that comes with climate change—provide perfect conditions for mosquitoes that carry malaria, West Nile and dengue fever. Warming makes mosquitoes bit more. They’ll face fewer predators, too. The frequent droughts expected in a greenhouse world are murder on damselflies and dragonflies. As dengue fever, yellow fever and malaria extend their range to higher elevations and higher latitudes, those diseases could appear in the developed woad, too. The southern tier of western and eastern Europe, as well as the southern United States, are most at risk, says Harvard’s Epstein. Dengue fever has already popped up on the Mexican side of the U.S. border, a worrisome expansion of its current range. Say this for the climate contrarians who insist that a warmer world will he a better, more productive world: if they’re referring to allergens and pathogens, they’re dead right. In Paragraph 2, when the author says "...that is only the beginning. " he means
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接标准的性质分为三类的是技术标准、管理标准和工作标准。
在类型说明符号中，双精度浮点数用______表示，字符串型数据用______表示，整型数据用______表示。
What accounts for the great outburst of major inventions in early America-breakthroughs such as the telegraph, the steamboat and the weaving machine Among the many shaping factors, I would single out the country’’s excellent elementary schools; a labor force that welcomed the new technology; the practice of giving premiums to inventors; and above all the American genius for nonverbal," spatial" thinking about things technological. Why mention the elementary schools Because thanks to these schools our early mechanics ,especially in the New England and Middle Atlantic states, were generally literate and at home in arithmetic and in some aspects of geometry and trigonometry. Acute foreign observers related American adaptiveness and inventiveness to this educational advantage. As a member of a British commission visiting here in 1853 reported," With a mind prepared by thorough school discipline, the American boy develops rapidly into the skilled workman." A further stimulus to invention came from the "premium" system, which preceded our patent system and for years ran parallel with it. This approach, originated abroad, offered inventors medals, cash prizes and other incentives. In the United States, multitudes of premiums for new devices were awarded at country fairs and at the industrial fairs in major cities. Americans flocked to these fairs to admire the new machines and thus to renew their faith in the beneficence of technological advance. Given this optimistic approach to technological innovation, the American worker took readily to that special kind of nonverbal thinking required in mechanical technology. As Eugene Ferguson has pointed out," A technologist thinks about objects that cannot be reduced to unambiguous verbal descriptions; they are dealt with in his mind by a visual, nonverbal process. The designer and the inventor are able to assemble and manipulate in their minds devices that as yet do not exist." This nonverbal "spatial" thinking can be just as creative as painting and writing. Robert Fulton once wrote," The mechanic should sit down among levers, screws, wedges, wheels, etc., like a poet among the letters of the alphabet, considering them as an exhibition of his thoughts, in which a new arrangement transmits a new idea." When all these shaping forces-- schools, open attitudes, the premium system, a genius for spatial thinking -- interacted with one another on the rich U. S. mainland, they produced that American characteristic, emulation. Today that word implies mere imitation. But in earlier times it meant a friendly but competitive striving for fame and excellence. It is implied that adaptiveness and inventiveness of the early American mechanics______.
While no woman has been President of the United States, yet the world does have several thousand years of experience with female leaders, and I have to acknowledge it: their historical record puts men’s to shame. A notable share of the great leaders in history have been women: Queen Hatshepsut and Cleopatra of Egypt, Empress Wu Zetian of China, Isabella of Castile, Queen Elizabeth I of England, Catherine the Great of Russia, and Maria Theresa of Austria. Granted, I’m neglecting the likes of Bloody Mary, but it’s still true that those women who climbed to power in monarchies had an astonishingly high success rate. Research by political psychologists points to possible explanations. Scholars find that women, compared with men, tend to excel in consensus-building and certain other skills useful in leadership. If so, why have female political leaders been so much less impressive in the democratic era Margaret Thatcher was a transformative figure, but women have been mediocre prime ministers or presidents in countries like Sri Lanka, India, Bangladesh, Pakistan, the Philippines and Indonesia. Often, they haven’t even addressed the urgent needs of women in those countries. I have a pet theory about what’s going on. In monarchies, women who rose to the top dealt mostly with a narrow elite, so they could prove themselves and get on with governing. But in democracies in the television age, female leaders also have to navigate public prejudices—and these make democratic politics far more challenging for a woman than for a man. In a common experiment, the "Goldberg paradigm", people are asked to evaluate a particular article or speech, supposedly by a man. Others are asked to evaluate the identical presentation, but from a woman. Typically, in countries all over the world, the very same words are rated higher coming from a man. In particular, one lesson from this research is that promoting their own successes is a helpful strategy for ambitious men. But experiments have demonstrated that when women highlight their accomplishments, that’s a turn-off. And women seem even more offended by self-promoting females than men are. This creates a huge challenge for ambitious women in politics or business: if they’re self-effacing, people find them unimpressive, but if" they talk up their accomplishments, they come across as pushy braggarts. The broader conundrum is that for women, but not for men, there is a tradeoff in qualities associated with top leadership. A woman can be perceived as competent or as likable, but not both. "It’s an uphill struggle, to be judged both a good woman and a good leader," said Rosabeth Moss Kanter, a Harvard Business School professor who is an expert on women in leadership. Professor Kanter added that a pioneer in a man’s word, like Hillary Rodham Clinton, also faces scrutiny on many more dimensions than a man—witness the public debate about Mrs. Clinton’s allegedly "thick ankles,"or the headlines last year about cleavage. Clothing and appearance generally matter more for women than for men, research shows. Surprisingly, several studies have found that it’s actually a disadvantage for a woman to be physically attractive when applying for a managerial job. Beautiful applicants received lower ratings, apparently because they were subconsciously pegged as stereotypically female and therefore unsuited for a job as a boss. Female leaders face these impossible judgments all over the world. An M. I. T. economist, Esther Duflo, looked at India, which has required female leaders in one-third of village councils since the mid-1990s. Professor Duflo and her colleagues found that by objective standards, the women ran the villages better than men. For example, women constructed and maintained wells better, and took fewer bribes. Yet ordinary villagers themselves judged the women as having done a worse job, and so most women were not re-elected. That seemed to result from prejudice. Professor Duflo asked villagers to listen to a speech, identical except that it was given by a man in some cases and by a woman in others. Villagers gave the speech much lower marks when it was given by a woman. Such prejudices can be overridden after voters actually see female leaders in action. While the first ones received dismal evaluations, the second round of female leaders in the villages were rated the same as men. "Exposure reduces prejudice," Professor Duflo suggested. Women have often quipped that they have to be twice as good as men to get anywhere—but that, fortunately, is not difficult. In fact, it appears that it may be difficult after all. Modern democracies may empower deep prejudices and thus constrain female leaders in ways that ancient monarchies did not. It can be inferred from the passage that prejudice against female leaders
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