Why Is it So Difficult to Swat a Fly?
      The brains of flies are wired to avoid the swatter, US researchers said on Thursday.
      At the mere hint of a threat, the insects adjust their preflight stance to flee in the opposite direction, ensuring a clean getaway, they said in a finding that helps explain why flies can so easily evade swipes from their human foes.
      "These movements are made very rapidly, within about 200 milliseconds, but within that time the animal determines where the threat is coming and activates a set of movements to position its legs and wings," Michael Dickinson of the California Institute of Technology said in a statement.
      "This illustrates how rapidly the fly's brain can process sensory information into an appropriate motor response," said Dickinson, whose research appears in the journal Current Biology.
       Dickinson's team studies this process in fruit flies using high-speed digital imaging equipment and a fancy fly swatter.
       In response to a threat from the front, the fly moves its middle legs forward, leans back and raises its back legs for a backward takeoff. If the threat is from the side, the fly leans the other way before takeoff.
       The findings offer new insight into the nervous system of the fly, and lends a few clues on how to outsmart them.
       Dickinson, a bioengineer, has devoted his life's work to the study of insect flight. He has built a tiny robotic fly called Robofly and a 3-D visual flight simulator called Fly-O-Vision.

                                                                                            The Truth about the
Environment
      For many environmentalists, the world seems to be getting worse. They have developed a hit-list of our main fears: that natural resources are running out; that the population is ever growing, leaving less and less to eat; that species are becoming extinct in vast numbers, and that the planet's air and water are becoming ever more polluted.
     But a quick look at the facts shows a different picture. First, energy and other natural resources have become more abundant, not less so, since the book The Limits to Growth was published in 1972 by a group of scientists. Second, more food is now produced per head of the world's population than at any time in history. Fewer people are starving. Third, although species are indeed becoming extinct, only about 0.7% of them are expected to disappear in the next 50 years, not 25-50%, as has so often been predicted. And finally, most forms of environmental pollution either appear to have been exaggerated, or are temporary-associated with the early phases of industrialisation and therefore best cured not by restricting economic growth, but by accelerating it. One form of pollution—the release of greenhouse gases that causes global warming—does appear to be a phenomenon that is going to extend well into our future, but its total impact is unlikely to pose a devastating problem.
     Yet opinion polls suggest that many people nurture the belief that environmental standards are declining and many factors seem to cause this disjunction between perception and reality.

     森林里住着三只蜥蜴1，觉得身体和周围的环境大不相同，没有安全感。其中一只说：“这里实在不安全，得想办法改变环境。”说完，这只蜥蜴便开始大干起来。森林之大，要使之改变谈何容易。不久这只蜥蜴便活活累死
了。
    另一只蜥蜴说：“看来想要改变这个地方非我辈能力所及，不如另寻安全的地方。”说完，便爬出了这片森林。只是它还没有找到梦中的乐土，就饿死了。
    第三只蜥蜴看了看四周，说：“为什么一定要改变环境，而不改变自己来适应环境?”说完，它便借着阳光和阴影，慢慢地改变自己的肤色。于是它渐渐地在树干上隐没了。这只蜥蜴就成了变色龙2，从此在森林里安居繁衍。
* 蜥蜴：lizard

   美国人认为，向人借钱的是聪明人，借钱给人的是傻瓜。美国政府、企业和普通百姓都以此为准则，使资源丰富的美国成为欠债最多的国家。美国人用明天的钱，使今天的楼市一落千丈、通胀加剧。无论是美国政府还是企业和个人，总认为美国是世界最富裕的国家，可以为所欲为地借钱、用钱。然而，靠借钱过日子的国家，总不是一个健康的国家。“不用花一分钱可以成为豪宅业主”，终于引发了波及全球的金融危机；靠印钞票来掠取他国资产，会使自己的诚信彻底丧失。不负责任地“向人借钱的聪明人”，反被聪明所误，这已成为威胁美国安全的因素之