1、Genetically modified foods - Feed the World? If you want to spark a heated debate at a dinner party, bring up the topic of genetically modified foods. For many people, the concept of genetically altered, high-tech crop production raises all kinds of environmental, health, safety and ethical question
2、s. Particularly in countries with long agrarian traditions - and vocal green lobbies - the idea seems against nature.如果你想在某次晚宴上挑起一场激烈的争论，那就提出转基因食品的话题吧。对许多人来说，高科技的转基因作物生产的概念会带来诸如环境、健康、安全和伦理等方面的各种问题。特别是在有悠久的农业生产传统和主张环保的游说集团的国家里，转基因食品的主意似乎有悖自然。In fact, genetically modified foods are already very much a
3、 part of our lives. A third of the corn and more than half the soybeans and cotton grown in the US last year were the product of biotechnology, according to the Department of Agriculture. More than 65 million acres of genetically modified crops will be planted in the US this year. The genetic is out
4、 of the bottle.事实上，转基因食品已经成为我们生活重要的一部分。根据农业部的统计，美国去年所种植玉米的13，大豆和棉花的一半以上都是生物技术的产物。今年，美国将种植6500多万英亩的转基因作物。基因妖怪已经从瓶子里跑出来了。Yet there are clearly some very real issues that need to be resolved. Like any new product entering the food chain, genetically modified foods must be subjected to rigorous testing.
5、 In wealthy countries, the debate about biotech is tempered by the fact that we have a rich array of foods to choose from - and a supply that far exceeds our needs. In developing countries desperate to feed fast-growing and underfed populations; the issue is simpler and much more urgent: Do the bene
6、fits of biotech outweigh the risks?但是，显然还有一些非常现实的问题需要解决。就像任何一种要进入食物链的新食品一样，转基因食品必须经过严格的检验。在富裕的国家里，由于有大量丰富的食品可供选择，而且供应远远超过需求，所以关于生物技术的争论相对缓和一些。在迫切想要养活其迅速增长而又吃不饱的人口的发展中国家，问题比较简单，也更加紧迫：生物技术的好处是否大于风险呢?The statistics on population growth and hunger are disturbing. Last year the worlds population reached
7、6 billion. And by 2050, the UN estimates, it will probably near 9 billion. Almost all that growth will occur in developing countries. At the same time, the worlds available cultivable land per person is declining. Arable land has declined steadily since 1960 and will decease by half over the next 50
8、 years, according to the International Service for the Acquisition of Agri-Biotech Applications (ISAAA).关于人口增长和饥饿的统计数字读来令人感到不安。去年，世界人口达到了60亿。联合国预测，到2D0年，这个数字很可能将接近90亿，而增加的人口几乎都来自发展中国家。与此同时，世界人均耕地正在减少。国际农业生物工程应用技术采购管理局(ISAAA)称，自1960年以来，耕地面积一直持续下降，并将在今后50年减少一半。The UN estimates that nearly 800 million
9、people around the world are undernourished. The effects are devastating. About 400 million women of childbearing age are iron deficient, which means their babies are exposed to various birth defects. As many as 100 million children suffer from vitamin A deficiency, a leading cause of blindness. Tens
10、 of millions of people suffer from other major ailments and nutritional deficiencies caused by lack of food.联合国估计，世界上有近8亿人口营养不良。它产生的效应是破坏性的。大约有4亿的育龄妇女体内缺铁，也就是说，她们的婴儿将可能有各种天生的缺陷。数量多达1亿的儿童缺乏维生素A，这是导致失明的主要原因。还有数千万的人患有因食物匮乏而导致的其他严重疾病和营养不良症。 How can biotech help? Biotechnologists have developed genetical
11、ly modified rice that is fortified with beta-carotene - which the body converts into vitamin A - and additional iron, and they are working on other kinds of nutritionally improved crops. Biotech can also improve farming productivity in places where food shortages are caused by crop damage attributio
12、n to pests, drought, poor soil and crop viruses, bacteria or fungi.生物技术对此能做些什么呢?生物技术专家已经培育出了含有胡萝卜素(身体可将之转化为维生素A)和更多铁元素的转基因水稻，目前正在研究培育其他一些增进营养成分的农作物。生物技术还可以帮助提高因虫害、干旱、土壤贫瘠和作物病毒、细菌或真菌导致作物减产而出现食物匮乏的地区的农业生产率。Damage caused by pests is incredible. The European corn borer, for example, destroys 40 million
13、tons of the worlds corn crop annually, about 7% of the total. Incorporating pest-resistant genes into seeds can help restore the balance. In trials of pest-resistant cotton in Africa, yields have increased significantly. So far, fears that genetically modified, pest-resistant crops might kill good i
14、nsects as well as bad appear unfounded.虫害带来的损失令人难以置信。例如，欧洲玉米螟每年毁掉4000万吨玉米，占世界玉米总产量的7。把抗虫害的基因植入种子可以帮助避免这一损失。在非洲进行的抗虫害棉花试验中，棉花的产量已大幅度提高。有人担心，抗虫害的转基因作物不仅将害虫杀死，而且有可能连益虫也一起杀死，但到目前为止，这种担心似乎没有根据。Viruses often cause massive failure in staple crops in developing countries. Two years age, Africa lost more tha
15、n half its cassava crop - a key source of calories - to the mosaic virus. Genetically modified, virus-resistant crops can reduce that damage, as can drought-tolerant seeds in regions where water shortages limit the amount of land under cultivation. Biotech can also help solve the problem of soil tha
16、t contains excess aluminum, which can damage roots and cause many staple-crop failures. A gene that helps neutralize aluminum toxicity in rice has been identified.病毒常常在发展中国家造成主要粮食作物的大面积歉收。两年前，花叶病毒使非洲损失了超过一半的木薯，而这种作物是当地人的主要食物。转基因的抗病毒作物可以减少这种损失，就像抗干旱种子在可耕地面积因缺水而受到限制的地区起到的作用一样。含铝过高的土壤会损伤作物的根系并使许多主要作物歉收
17、，对于这种问题生物技术也能帮助解决。目前，研究人员已经识别出一种有助于中和水稻里铝的毒性的基因。Many scientists believe biotech could raise overall crop productivity in developing countries as much as 25% and help prevent the loss of those crops after they are harvested.许多科学家认为，生物技术能够把发展中国家的农业总产量提高25，并且帮助防止作物收割后遭受损失。Yet for all that promise, biot
18、ech is far from being the whole answer. In developing countries, lost crops are only one cause of hunger. Poverty plays the largest role. Today more than 1 billion people around the globe live on less than 1 a day. Making genetically modified crops available will not reduce hunger if farmers cannot
19、afford to grow them or if the local population cannot afford to buy the food those farmers produce.尽管具有这么多潜力，生物技术还远远不能解决全部问题。在发展中国家，作物歉收只是造成饥饿的一个原因。贫穷才是罪魁祸首。今天，全世界有超过10亿人口每天靠不到1美元维持生计。如果农民没钱种植转基因作物或当地人买不起农民种出的粮食，培育转基因作物就无法减少饥饿。Nor can biotech overcome the challenge of distributing food in developing
20、 countries. Taken as a whole, the world produces enough food to feed everyone - but much of it is simply in the wrong place. Especially in countries with undeveloped transport infrastructures, geography restricts food availability as dramatically as genetics promises to improve it.此外，生物技术也无法克服在发展中国家
21、分配粮食的难题。从整体上看，世界生产的粮食足够养活所有人，但大部分粮食却不是在需要的地方。尤其在运输基础设施落后的国家，地理条件对食物供给的限制正如遗传学为食物供给带来的希望一样大。 Biotech has its own distribution problems. Private-sector biotech companies in the rich countries carry out much of the leading-edge research on genetically modified crops. Their products are often too costly
22、 for poor farmers in the developing world, and many of those products wont even reach the regions where they are most needed. Biotech firms have a strong financial incentive to target rich markets first in order to help them rapidly recoup the high costs of product development. But some of these com
23、panies are responding to needs of poor countries. A London-based company, for example, has announced that it will share with developing countries technology needed to produce vitamin-enriched golden rice.生物技术也面临自身的“分配”问题。许多转基因作物方面的尖端研究都是富国的私营生物技术公司进行的。对发展中国家的穷苦农民来说，这些公司的产品通常显得过于昂贵，而且这些产品中的大部分甚至无法到达最
24、需要的地区。强大的经济刺激促使生物技术公司把富裕国家的市场作为第一目标，以便能够尽快回收产品开发的高额成本。不过，有些公司已开始对贫穷国家的需要做出反应。例如，一家总部在伦敦的公司已经宣布，它愿意和发展中国家一起分享生产维生素增强型的“金水稻”所需的技术。More and more biotech research is being carried out in developing countries. But to increase the impact of genetic research on the food production of those countries, there
25、 is a need for better collaboration between government agencies - both local and in developed countries - and private biotech firms. The ISAAA, for example, is successfully partnering with the US Agency for International Development, local researches and private biotech companies to find and deliver
26、 biotech solutions for farmers in developing countries.发展中国家正在进行越来越多的生物技术研究。但是，为扩大遗传学研究对这些国家的粮食生产的影响，政府各部门(包括当地政府部门和发达国家的政府部门)与私营生物技术公司之间需要更好的合作。例如，国际农业生物工程应用技术采购管理局目前正与美国国际发展署、当地的研究人员以及私营的生物技术公司进行成功的合作，以帮助发展中国家的农民寻求生物技术方面的解决办法。 Will Frankenfoods feed the world? Biotech is not a panacea, but it does
27、 promise to transform agriculture in many developing countries. If that promise is not fulfilled, the real losers will be their people, who could suffer for years to come.“弗兰肯食品”能养活世界吗?生物技术虽不是万灵药，但它确实有希望改造许多发展中国家的农业。如果这种希望不能实现，真正的受害者将是这些国家的人民，他们可能会在未来的岁月里遭受苦难。 The Biology of Skin Color：Black and Whi
28、te 10年之前当时在西澳大学的人类学家Nina Jalonski被要求做一项关于人类皮肤的演说。作为灵长类进化研究的专家，她决定对肤色的进化史研讨一番，可是当她对课题进行文献研究时，结果却使她倍感失望。在1970年之前的较为新的理论都存在种族主义，而另外的文献则相当缺乏说服力。比如，有研究发表说白色皮肤可以更好的抵御寒冷。1970年之后，研究人员渐渐认识到对于研究皮肤这样的课题变的无足轻重，因为这样的研究总是收获甚微。Jalonski说：这个事实人人皆知，只是无人再议而已。不久之后，Jablonski和她的丈夫Geoge Chaplin（一位地理信息系统专家）发表了第一份综合性肤色论。该文章
29、发表于人类进化日报中，该文章说明了肤色与全球光线强度之间存在强烈且可预测的关联。但同时他们的发现也产生了一个深层次且令人吃惊的结论：肤色与维他命存在密切的联系。作为加利福尼亚学术研究部门的领导，Jablonski首先假设我们最早的人类祖先有着与大猩猩（生物学角度最密切）类似的皮肤。在450万年到200万年以前，早起人类从热带雨林中脱离，开始走向非洲东部大草原。在以前的大草原上，人们不仅仅要更多的暴露于阳光下，而且他们忙于收集食物。哺乳动物的大脑非常害怕过热，只需要5、6个级别的热量就能使他们中暑，因此我们祖先不得不发明更好的解暑办法。答案很简单，那就是通过蒸发带走热量。早起人类可能汗腺极少就像
30、大猩猩一样，汗腺可能主要集中于他们的手掌中和脚底。然而有时，某些个体会比通常的个体长更多汗腺。这些汗腺更多的人，他们可以在热量驱逐他们躲在阴凉下之前有更长的时间去找食物。因此他们能得到更多食物，使得他们能孕育更健康的后代，并且将发达的汗腺遗传给后代。在几百万年的自然选择后，人类的身体上已经拥有大约200万个汗腺。人类的皮肤相对于大猩猩的毛减少许多。加利福尼亚大学的人类学家Adrienne Zihlaman说：这样使得我们人类在沐浴后毛发干燥的更快。然而，缺少毛发的皮肤非常容易遭到紫外线的破坏。科学家提出了一种假说：人类的肤色由黑色素所决定，而黑色素可以吸收或者分解紫外线。但是紫外线是什么呢？一
31、些研究人员只出它是皮肤癌的起因。癌症通常是由于人体的恶性增殖，是由日常生活习惯引起的。还有一些事实表明阳光晒过的乳腺将影响女性哺乳，但是较为黝黑的皮肤可以有效保护这些哺乳女性。Jablonski在澳大利亚准备演讲期间，她曾做过关于紫外线对叶酸（一种维他命B的混合物）的影响的研究。研究表明如果你的皮肤白净那么强烈的阳光会使得叶酸等级减半。Jablonski发现这个关系仅用了几周的时间。在胚胎开发的高级阶段，Jablonski了解到过低的叶酸水准与神经管损伤相关，比如脊柱裂或先天无脑畸形（婴儿生来就没有健全的大脑和脊柱）。Jablonski随后通过三篇文献得知孩子的神经管损伤与它的母亲孕期暴露于紫
32、外线下密切相关。而且她发现叶酸与精液水平密切相关通过抑制叶酸可以起到避孕作用。（Jablonski说：叶酸无处不在，它几乎影响我们的全身上下）。她现在发现了一些有趣的证明：叶酸让会我们慢慢进化出黑色皮肤，但是为什么有人皮肤却很白呢。追溯到1960年，生物学家W.FarsworthLooms曾发表说肤色与人体的维生素D水平相关。而维他命D可以帮助人体吸收钙质构成坚硬的骨骼，尤其是快速发育的胚胎。(孕期需要很多的维生素D，这也就解释了为什么从世界范围来看女性的皮肤要比男性白皙。)不同于叶酸，维生素D需要紫外线的配合以发挥作用。Loomis坚信生活在北方的人由于那里光线较弱所以他们的皮肤较为白以便吸
33、收更多的紫外线；而生活在热带地区的人们则长有黑色皮肤以便阻挡阳光，使得身体吸收较为均衡的维生素D不至于过量（过量的维生素D会有毒性）。由于Jablonski的研究Loomis的部分研究成果已经被证明是错误的。Jablonski说：你可以永远不乏获得过量维生素D，因为只有极少数的人们会发生鱼肝油过量。但是Loomis对于皮肤白皙的论点是正确的，这个论点完美的证明了Jablonski对于叶酸和黑色皮肤的论点。接下的任务就是找到数据说明肤色与光线强度的关系。到80年代，研究人员只能估算紫外线到达地球表面的量，但是在1978年的时候NASA启动了全球臭氧光谱绘制计划。三年后，Jablonski和Cha
34、plin利用全球紫外线光谱数据，并且拿这些数据与他们统计的50个国家和地区的人们肤色进行对比。令他们兴奋不已的是，他们提出的结论完全正确：紫外线越弱，人们的肤色越白皙。Jablonski之后又统计了50个不同地区的严重缺少维生素D的人群。Jablonski说：这个人类历史解决维生素D缺乏是在他们学会钓鱼后，因此他们可以获得更加丰富的实物后，维生素D的问题就已经解决了。人类的历史中绝大多数时间用来不停地移动，因为这样他们在面对各种环境中才学会了使用工具，制作衣服，解决居住问题并且产生了自己的饮食习惯。但是Jablonski的论点指出我们的适应力非常强。热带的人们拥有黑色皮色以便他们阻挡紫外线以便
35、他们保护自己的叶酸水平。而远离赤道的人们在漫长的冬季中，长出了白皙的皮肤以便产生足够的维生素D。Jablonski希望她的研究可以改善人们饮食中的维生素D和叶酸的摄入量。比如，总所周知黑色皮肤的人去阴雨地带生活会产生像佝偻病等这样由于缺少维生素D而产生的症状。更重要的是，Jablonski希望人们可以通过她的研究改变会不同肤色的人们的看法。Jablonski说：我们应该将这个理论传播到热带地区，让人们去了解它，用它去解决分歧、误解等等，它完全有这个能力.Unit 9In popular culture, the term UFOor unidentified flying objectrefe
36、rs to a suspected alien spacecraft, although its definition encompasses any unexplained aerial phenomena. UFO sightings have been reported throughout recorded history and in various parts of the world, raising questions about life on other planets and whether extraterrestrials have visited Earth. Th
37、ey became a major subject of interestand the inspiration behind numerous films and booksfollowing the development of rocketry after World War II.通俗地说，所谓 UFO或者不明飞行物指疑似外星人的飞船，不过它的定义也包括无法解释的空中现象。在全世界各地不同时期都有 UFO 目击的报告，引起人们关于外星生命以及地外生命是否访问过地球的争论。在二战后火箭技术的发展下，它们成了人们感兴趣的一大主题也是数不清的电影和书籍背后的灵感来源。Flying Sauce
38、rs飞碟The first well-known UFO sighting occurred in 1947, when businessman Kenneth Arnold claimed to see a group of nine high-speed objects near Mount Rainier in Washington while flying his small plane. Arnold estimated the speed of the crescent-shaped objects as several thousand miles per hour and sa
39、id they moved “like saucers skipping on water.” In the newspaper report that followed, it was mistakenly stated that the objects were saucer-shaped, hence the term flying saucer.首个著名的飞碟目击事件发生在 1947 年，一个叫 Kenneth Arnold 的商人声称他在华盛顿的雷尼尔山附近玩小型飞机模型时看到了一组 9 个高速移动的物体。Arnold 估计这些月牙形的物体速度达每小时数千英里，还说他们的移动“就像是
40、打水漂”。在后来的新闻中错误地报道成了这些物体是碟形的，于是就有了飞碟这一称呼。Sightings of unidentified aerial phenomena increased, and in 1948 the U.S. Air Force began an investigation of these reports called Project Sign. The initial opinion of those involved with the project was that the UFOs were most likely sophisticated Soviet air
41、craft, although some researchers suggested that they might be spacecraft from other worlds, the so-called extraterrestrial hypothesis (ETH). Within a year, Project Sign was succeeded by Project Grudge, which in 1952 was itself replaced by the longest-lived of the official inquiries into UFOs, Projec
42、t Blue Book, headquartered at Wright-Patterson Air Force Base in Dayton, Ohio. From 1952 to 1969 Project Blue Book compiled reports of more than 12,000 sightings or events, each of which was ultimately classified as (1) “identified” with a known astronomical, atmospheric, or artificial (human-caused
43、) phenomenon or (2) “unidentified.” The latter category, approximately 6 percent of the total, included cases for which there was insufficient information to make an identification with a known phenomenon.之后不明的空中现象频发，在 1948 年美国空军开始对这些报告进行调查，称为 Sign 计划。这一计划的最初动机是怀疑这些 UFO 很可能是苏联尖端飞行器，虽然有些研究员认为它们可能是来自其
44、他世界的飞船，也就是所谓的外星人假说（ETH）。在一年内，Grudge 计划继承了 Sign 计划，到了 1952 年它又被 UFO 官方研究计划中历时最长的 Blue Book 计划取代，其总部位于俄亥俄州代顿市的 Wright-Patterson 空军基地。在 1952 年至 1969 年间，Blue Book 编辑了一万两千多宗目击事件的报告，每一个最后都标上“已确认”或者“未确认”，“已确认”的包括已知的天文现象、大气现象和人造（人为引起的）现象。后者约占总数的 6%，包括了一些信息不足，无法用已知的现象定性的事件。The Robertson Panel and the Condon
45、ReportRobertson 小组和 Condon 报告An American obsession with the UFO phenomenon was under way. In the hot summer of 1952 a provocative series of radar and visual sightings occurred near National Airport in Washington, D.C. Although these events were attributed to temperature inversions in the air over th
46、e city, not everyone was convinced by this explanation. Meanwhile, the number of UFO reports had climbed to a record high. This led the Central Intelligence Agency to prompt the U.S. government to establish an expert panel of scientists to investigate the phenomena. The panel was headed by H.P. Robe
47、rtson, a physicist at the California Institute of Technology in Pasadena, Calif., and included other physicists, an astronomer, and a rocket engineer. The Robertson Panel met for three days in 1953 and interviewed military officers and the head of Project Blue Book. They also reviewed films and phot
48、ographs of UFOs. Their conclusions were that (1) 90 percent of the sightings could be easily attributed to astronomical and meteorologic phenomena (e.g., bright planets and stars, meteors, auroras, ion clouds) or to such earthly objects as aircraft, balloons, birds, and searchlights, (2) there was n
49、o obvious security threat, and (3) there was no evidence to support the ETH. Parts of the panels report were kept classified until 1979, and this long period of secrecy helped fuel suspicions of a government cover-up.而美国人已经开始对 UFO 现象着迷。在 1952 年炎热的夏天，在华盛顿特区的国家机场附近发生了一系列令人激动的雷达和肉眼观测报告。虽然这些报告被归结于城市上空空气的温度反转现象，并不是所有人都能接受这个解释。同时，UFO 报告的数量攀升
