网上科普有关“英语科普类文章”话题很是火热,小编也是针对英语科普类文章寻找了一些与之相关的一些信息进行分析,如果能碰巧解决你现在面临的问题,希望能够帮助到您。
科普 教育 对我国小康社会、和谐社会的建设有着重要的意义。下面是我带来的英语科普类 文章 ,欢迎阅读!
英语科普类文章1
听点小音乐 轻松学分数
Stuck on a tricky math problem? Start clapping. Grade school kids who learned about fractions through a rhythm-and-music-based curriculum outperformed their peers in traditional math classes. The work is inEducational Studies in Mathematics.
被一条数学题难住了?拍拍手试试吧。研究表明,小学生在有节奏感的音乐背景下学习分数知识的效果会好于传统课堂(具体研究发表在《数学教育研究》上的《学术性音乐:如何用音乐辅助三年级小学生学习基础分数》一文,作者:苏珊?科瑞等)。
Fractions let you divide up a measure of music into notes of varying length. For example, one four-beat measure could contain a single whole note held for all four beats, two half notes of two beats apiece, four quarter notes of a beat each, and so on. In the Academic Music program, based on the Kodaly method of musical education, students clap, drum and chant to memorize the lengths of musical notes?then solve problems in which fractional notes must add up to a full measure of music.
根据分数的概念,一节音乐可分成长短不一的几串音符。例如,一节四拍子的调子可包含一个代表四拍子的全音符,两个各代表一个二拍子的二分音符,四个各代表一个一拍子的四分音符以此类推。在?学术性音乐?项目中,研究人员以科达伊的音乐教育 方法 为基础,让学生通过打拍子、敲鼓、合唱记住各音符的长度,学生必须把这些片段加起来,才能得到一节完整的音乐如此实践可解决学生对分数的疑惑。
Sixty-seven students participated in the study. Half did math problems using the Academic Music system. And after six weeks, the students in the music program averaged 50 percent higher on tests than did the kids in regular math class. Fractions create a solid foundation for further math education?so mastering them is music to educators' ears.
有67名学生作为实验对象参与了本次研究,其中有一半在?学术性音乐?体系下解决数学问题。六周后,他们在测试中的得分要比普通班级中的学生平均高50%。分数是进一步进行数学知识教学的基础如此看来,这还多亏了教育者的耳朵。
英语科普类文章3
十万年前的颜料工作室
Archeologists have discovered a paint production studio in an ancient South African cave A new archaeological find may signify one of the great leaps in human cultural and cognitive history. Because researchers have discovered a 100,000-year-old art studio. It was known that ochre?rock with red or yellow pigments?was used for paint even that far back in history. But there was scant evidence for how it was prepared and handled. Then, in 2008, researchers uncovered an ochre mixing kit in a South African cave. They found two abalone shells, most likely used for paint mixing and storage. They also found ochre, bone, charcoal, grindstones and hammerstones. The researchers say the ochre was probably rubbed on quartzite slabs to create a fine powder. It was then mixed and heated with other crushed substances, including other stones or mammal-bone. Microscopic striations on the inner abalone surface likely are likely scrape marks left during paint mixing. The research was published in the journal Science. The paint may have been used for body adornment or for long-gone artwork. And the presence of this paint-production laboratory indicates that the early humans knew basic chemistry and could plan for the future.
考古学家在南非的一个古老洞穴中发现了一个油漆制作工作室。这个新的考古发现可能是人类 文化 和认知历史的最伟大的跨越之一。因为研究人员发现的这个工作室产生于十万年前。众所周知,拥有红色或**色素的赭石岩一直被广泛运用于绘画中,但却少有证据显示它是如何制作并运用的。2008年,研究人员 在南非的山洞中发现了赭石混合工具, 两个可能用于调漆和储存的鲍鱼壳,除此之外他们还发现了赭石,骨头,炭笔和石锤。研究人员称,这些赭石很有可能经过在石英岩板上仔细研磨后,得到上等的粉末,然后再与 其他石头或者是哺乳动物的粉末混合并加热。用显微镜观察鲍鱼壳的内表面,你可以发现一些刮痕,这些都有可能是在混合颜料的过程中留下来的。这个发现已经被刊登在科学期刊上。这些颜料可能一直被运用在人体 彩绘 和长久失传的艺术品上。而且这些颜料制作工作室的存在表明了早期人类对化学已有了基本的了解并具有了规划未来的能力。颜料工具的一小步,人类历史的一大步辛西亚莫。
英语科普类文章3
你知道发烧的妙处吗?
Fever can play a variety of roles, such as inhibiting pathogen replication. It also apparently increases the population of killer T cells of the immune system. Christopher Intagliata reports.
发烧有多种不同的作用,如抑制病菌复制。它还可以显著增加免疫系统中杀伤性T细胞的数量。
I've always thought that when I get a fever, it's my body trying to make things uncomfortable for the invading pathogen. And that's often true?higher temperatures can inhibit the bad guys' ability to replicate. But my fever may actually be a one-two-punch. In addition to slowing down the invader, the heat helps the immune system recruit more troops for a counter-attack. That finding appears in the Journal of Leukocyte Biology.
我很早就知道,发烧的时候,其实是我的身体正在对入侵的病原体做出抵抗。这是事实---高温可以抑制坏病菌复制的能力。但发烧更是一个组合打击。除了减缓病原体的入侵,高温可以帮助免疫系统召集更多的部队做出抵抗。这一研究发表在《白细胞生物学杂志》。
Researchers warmed up one group of mice to body temperatures of about 103 degrees Fahrenheit. They left another group at normal core temperature?about the same as ours. Then they injected both groups of mice with an antigen, a substance that attracts the attention of the immune system.
研究人员将一组老鼠的体温升高到103华氏度,另外一组保持正常体温---大约是人体温度。然后向这两组老鼠的体内注射抗原一种会引起免疫系统反应的物质。
Blood samples taken three days later revealed that the feverish mice had nearly twice as many killer T-cells: the kind of immune cells that can hunt down infected cells or tumor cells, and slaughter them.
三天后,这两组老鼠的血样表明,体温较高老鼠组体内的杀伤性T细胞是正常组的2倍,这种免疫细胞可以追踪感染细胞或癌细胞,并将其消灭。
So when you're sick and you get the chills, the authors say, your body may be trying to tell you to hop under some blankets. Lie down, warm up and send a message. The heat is on.
所以,当你生病或感到寒冷时,表示你的身体正直向你传达信息--裹条毯子。躺在床上吧,热起来,身体自会做出反应。热度来袭啊。
给一篇科普征文(文章,急求)
死海不死
在亚洲西部,巴勒斯坦和约旦交界处,有一个“死海”.远远望去,死海的波涛此起彼伏,无边无际.但是,谁能想到,如此浩荡的海水中竟没有鱼虾、水草,甚至连海边也寸草不生?这大概就是“死海”得名的原因吧.
然而,令人惊叹的是,人们在这无鱼无草的海水里,竟能自由游弋;即使是不会游泳的人,也总是浮在水面上,不用担心会被淹死.真是“死海不死”.
传说大约两千年前,罗马统帅狄杜进兵耶路撒冷,攻到死海岸边,下令处决俘虏来的奴隶.奴隶们被投入死海,并没有沉到水里淹死,却被波浪送回岸边.狄杜勃然大怒,再次下令将俘虏扔进海里,但是奴隶们依旧安然无恙.狄杜大惊失色,以为奴隶们受神灵保佑,屡淹不死,只好下令将他们全部释放.
那么,死海海水的浮力为什么这样大呢?因为海水的咸度很高.据统计,死海水里含有多种矿物质:135.46亿吨氯化钠(食盐);有63.7亿吨氯化钙;有20亿吨氯化钾;另外还有溴、锶等.把各种盐类加在一起,占死海全部海水的23%~25%.这样,就使海水的密度大于人体的密度,无怪乎人一到海里就自然漂起来,沉不下去.
死海是怎样形成的呢?请先听一个古老的传说吧.远古时候,这儿原来是一片大陆.村里男子们有一种恶习,先知鲁特劝他们改邪归正,但他们拒绝悔改.上帝决定惩罚他们,便暗中谕告鲁特,叫他携带家眷在某年某月某日离开村庄,并且告诫他离开村庄以后,不管身后发生多么重大的事故,都不准回过头去看.鲁特按照规定的时间离开了村庄,走了没多远,他的妻子因为好奇,偷偷地回过头去望了一眼.哎哟,转瞬之间,好端端的村庄塌陷了,出现在她眼前的是一片汪洋大海,这就是死海.她因为违背上帝的告诫,立即变成了石人.虽然经过多少世纪的风雨,她仍然立在死海附近的山坡上,扭着头日日夜夜望着死海.上帝惩罚那些执迷不悟的人们:让他们既没有淡水喝,也没有淡水种庄稼.
这当然是神话,是人们无法认识死海形成过程的一种猜测.其实,死海是一个咸水湖,它的形成是自然界变化的结果.死海地处约旦和巴勒斯坦之间南北走向的大裂谷的中段,它的南北长75公里,东西宽5至16公里,海水平均深度146米,最深的地方大约有400米.死海的源头主要是约旦河,河水含有很多的矿物质.河水流入死海,不断蒸发,矿物质沉淀下来,经年累月,越积越多,便形成了今天世界上最咸的咸水湖——死海.
几十年前,死海还是一片荒凉.为了开发利用它的资源,而今死海旁边已出现了一些工厂,同时修建了一些现代化的游泳池、高级旅馆和游乐场所.死海上空艳阳高照,海面空气清新,含氧量高,海水治病的功能不逊于温泉,吸引着许多游客.这样一来,就使它出现了不少生气.
但是,由于死海的蒸发量大于约旦河输入的水量,造成水面日趋下降.据专家统计,最近十年来,每年死海水面下降40到50厘米.长此下去,在不久的将来,南部较浅的地方,海水将会消失;较深的北部,数百年后也可能干涸.那时,死海真的要死了. 南州六月荔枝丹
幼年时只知道荔枝干的壳和肉都是棕褐色的.上了小学.老师讲授白居易的《荔枝图序》,读到"壳如红缯,膜如紫绡,瓤肉莹白如冰雪,浆液甘酸如醴酪,实在无法理解,荔枝哪里会是红色的!荔枝肉像冰雪那样洁白,不是更可怪吗?向老师提出疑问,老师也没有见过鲜荔枝,无法说明白,只好不了了之.假如是现在,老师纵然没有见过鲜荔枝,也可以找出科学的资料,给有点钻牛角尖的小学生解释明白吧.
白居易用比喻的笔法来描写荔枝的形态,的确也有不足之处.缯是丝织物,丝织物滑润,荔枝壳却是粗糙的.用果树学的术语来说,荔枝壳表面有细小的决状裂片,好象龟甲,特称龟裂片.裂片中央有突起部分,有的尖锐如刺,这叫做片峰.裂片大小疏密,片峰尖平,都因品种的不同而各异.
成熟的荔枝,大多数是深红色或紫色.生在树头,从远处当然看不清它壳面的构造,只有红色映入眼帘,因而把它比做"绛囊"、"红星"、"珊瑚珠",都很逼真.至于整株树以至成片树林,那就成为"飞焰欲横天""红云几万重"的绚丽景色了.荔枝的成熟,广东是四月下旬到七月,福建是六月下旬到八月,都以七月为盛期,"南州六月荔枝丹"指的是阴历六月,正当阳历七月.荔枝也有淡红色的,如广东产的"三月红"和"桂绿"等.又有黄荔,淡**而略带淡红.荔枝呈心脏形、卵圆形或圆形,通常蒂部大,顶端稍小.蒂部周围微微突起,称为果肩;有的一边高,一边低.顶端叫果顶,浑圆或尖圆.两侧从果顶到蒂部有一条沟,叫做缝合线,显隐随品种而不同.旧记载中还有一些稀奇的品种,如细长如指形的"龙牙"、圆小如珠的"珍珠",因为缺少经济价值,现在已经绝种了.
荔枝大小,通常是直径三四厘米,重十多克到二十多克.六十年代,广东调查得知,有鹅蛋荔和丁香大荔,重达四五十克.还有四川合江产的"楠木叶",《四川果树良种图谱》说它重十九克左右,《中国果树栽培学》则说大的重六十克.所谓"膜如紫绡",是指壳内紧贴壳的内壁的白色薄膜.说它"如紫绡",是把壳内壁的花纹误作膜的花纹了.明代徐勃有一首《咏荔枝膜》诗,描写吃荔枝时把壳和膜扔在地上,好似"盈盈荷瓣风前落,片片桃花雨后娇",是夸张的说法.
荔枝的肉大多数白色半透明,说它"莹白如冰雪",完全正确.有的则微带**.从植物学的观点看,它不是果肉,而是种子外面的层膜发育而成的,应称做假种皮.真正的果肉倒是前面说的连同果壳扔掉的那一层膜.荔枝肉的细胞壁特别薄,所以入口一般都不留渣滓.味甜微酸,适宜于生食.有的纯甜.早熟品种则酸味较强.荔枝晒干或烘干,肉就成红褐色,完全失去洁白的面貌.
荔枝不耐贮藏,正如白居易说的:"一日而色变,二日而香变,三日而味变,四五日外,色香味尽去矣."现经研究证实,温度保持在1℃到5℃,可贮藏三十天左右.还应进一步设法延长贮藏期,以利于长途运输,因为荔枝不耐贮藏,古代宫延想吃荔枝,就要派人兼程飞骑从南方远送长安或洛阳,给人民造成许多痛苦.唐明皇为了宠幸杨贵妃,就干过这样的事,唐代杜牧诗云:"长安回望诱成堆,山顶千门次第开.一骑红尘妃子笑,无人知是荔枝来."就是对这件事的嘲讽.
荔枝的核就是种子,长圆形,表面光滑,棕褐色,少数品种为绿色.优良的荔枝,种子发育不全,形状很小,有似丁香,也叫焦核.现在海南岛骨无核荔枝,核就更加退化了.
荔枝花期是二月初到四月初,早晚随品种而不同.广东有双季荔枝,一年开花两次.又有四季荔枝,一年开花四次之多.花形小,绿白色或淡**,不耀眼.花分雌雄,仅极少数品种有完全花.雌雄花往往不同时开放,宜选择适当的品种混栽在一起,以增加授粉的机会.一个荔枝花序,生花可有一二千朵,但结实总在一百以下,所以有"荔枝十花一子"的谚语.荔枝花多,花期又长,是一种重要的蜜源植物.
荔枝原产于我国,是我国的特产.海南岛和廉江有野生的荔枝林,可为我国是原产地的明证.据记载,南越王尉佗曾向汉高祖进贡荔枝,足见当时广东已有荔枝.它的栽培历史,就从那个时候算起,也已在二千年以上了.唐代对四川荔枝多有记述.自从蔡襄的《荔枝谱》(1059)成书以后,福建荔枝也为所重视.广西和云南也产荔枝,却有少有人说起.
古代讲荔枝的书,包括蔡襄的在内,现在知道的共有十三种,以记福建所产的为多,尚存八种;记载广东所产的仅存一种.清初陈鼎一谱,则对川、粤、闽三省所产都有记载.蔡谱不仅是我国,也是世界的果树志中,著作年代最早的一部.内容包括荔枝的产地、生态、功用、加工、运销以及有关荔枝的史事,并记载了荔枝的三十二个品种.其中"陈紫"一种现在在仍然广为栽培."宋公荔枝"现名"宋家香",有老树一株,尚生长在莆田宋氏祠堂里,依然每年开花结实.这株千年古树更足珍惜.
荔枝是亚热带果树,性喜温暖,成都、福州是它生长的北限.汉武帝曾筑扶荔宫,把荔枝移植到长安,没有栽活,迁怒于养护的人,竟然对他们施以极刑.宋微宗时,福建"以小株结实者置瓦器中,航海至阙下,移植宣和殿".微宗写诗吹嘘说:"密移造化出闽山,禁御新栽荔枝丹."实际上不过当年成熟一次而已.明代文征明有《新荔篇》诗,说常熟顾氏种活了几株,"仙人本是海山姿,从此江乡亦萌蘖."但究竟活了多少年,并无下文.现在科学发达,使荔枝北移,将来也许不是完全不可有的事.
我国幅员广阔,不同地区有不同的特产.因地制宜,努力发展本地区的特产,是切合实际的做法.盛产荔枝的地区,应该大力发展荔枝的生产.苏轼有诗云:"罗浮山下四时春,卢橘杨梅次第新.日啖荔枝三百颗,不妨长作岭南人."但日啖三百颗,究竟能有几人呢?社会主义现代化的荔枝生产,应该能够逐步满足广大人民的生活需要.
科普类英语文章
节约能源 从我做起
自1831年英国科学家法拉第发现发电的原理以来,在不到两百年的时间里,电已经成了不可或缺的重要能源。有了它,我们可以使用电灯、电视机、空调、洗衣机、电冰箱、电脑等家用电器;有了它,城市的夜晚就会变得灯火通明,交通事故也减少了;有了它,工厂的机器为我们织出了一件件漂亮的衣裳。
不过,根据科学家的研究,用于发电的各种能源,如石油、煤炭、天然气等是有限的、不可再生的,终有用完的一天。依目前人类耗能的平均速度计算,2050年前后石油就会枯竭,即使是最丰富的太阳能,在数十亿年后也会耗尽。假如汽车熄了火,电灯不能亮了,电视没了图象与声音,电脑成了摆设,这是一幅多么可怕的景象,简直就是“世界末日”了。但是这种情景是完全可能发生的,虽然科学家不断研究地热、沼气、风能、太阳能、核能等,希望取代石油,可是一直没有突破性的发展。在新能源尚未开发成功,而旧能源又日渐枯竭的情况下,人们应当尽量减少能源的浪费。尤其是我国本身能源又有限,因此,就必须提高能源的使用效率。
节约能源,必须从身边开始,从自已做起,主要方法有:
一、 养成随手关灯的习惯。
二、 洗澡时动作要迅速,不边洗边玩。
三、 减少开电冰箱的次数。
四、 夏天空调器的温度不要调节器得太低。
五、 不要无休止地听音乐、玩电脑游戏、看电视等。
总之,在我们的生活中,衣、食、住、行等必须依靠能源,才能够制造和使用,所以我们的生活应该力求俭朴,减少任何不必要的浪费,才是节约能源的最好办法
随着科学技术的飞速发展和全球化进程的不断加快,科普 文章 在向社会大众普及科学技术知识,提高公众科学素养等方面发挥着举足轻重的作用。下面是我带来的科普类英语文章,欢迎阅读!
科普类英语文章
生物与环境平衡的危机
The history of life on earth has been a history of interaction between living things and their surroundings. To a large extent, the physical form and the habits of the earth?s vegetation and its animal life have been molded by the environment. Considering the whole span of earthly time, the opposite effect, in which life actually modifies its surroundings, has been relatively slight. only in the present century has one species man acquired significant power to alter the nature of his world.
During the past quarter century this power has not only become increasingly great but it has changed in character. The most alarming of all man?s assaults upon the environment is the contamination of air, earth, rivers, and sea with dangerous and even lethal materials. This pollution is for the most part irrecoverable. In this now universal contamination of the environment, chemicals are the sinister partners of radiation in changing the very nature of the world the very nature of its life. Chemicals sprayed on croplands or forests or gardens lie long in soil, entering into living organisms, passing from one to another in a chain of poisoning and death. Or they pass mysteriously by underground streams until they emerge and combine into new forms that kill vegetation, sicken cattle, and work unknown harm on those who drink from once pure wells. "Man can hardly even recognize the devils of his own creation," as a scientist has said.
It took hundreds of millions of years to produce the life that now inhabits the earth. Given time not in years but in millennia life adjusts, and a balance has been reached. But in the modern world there is no time.
The rapidity of change follows the impetuous pace of man rather than the deliberate pace of nature. Radiation is now the unnatural creation of man?s tampering with the atom. The chemicals are the synthetic5 creations of man?s inventive mind, having no counterparts in nature.
To adjust to these chemicals would require not merely the years of a man?s life but the life of generations. And even this, were it by some miracle possible, would be futile, for the new chemicals come from our laboratories in an endless stream; almost five hundred annually find their way into actual use in the United States alone. Among them are many that are used in man?s war against nature. Since the mid 1940?s over 200 basic chemicals have been created for use in killing insects, weeds, and other organisms described as "pests."
It is not my contention that chemical insecticides must never be used. I do contend that we have put poisonous and biologically potent chemicals indiscriminately into the hands of persons largely or wholly ignorant of their potentials for harm. We have subjected enormous numbers of people to contact with these poisons, without their consent and often without their knowledge. I contend, furthermore, that we have allowed these chemicals to be used with little or no advance investigation of their effect on soil, water, wildlife, and man himself. Future generations are unlikely to forgive our lack of concern for the integrity of the natural world that supports all life.
地球上生命的历史一直就是一部生物与其环境相互作用的历史。在很大程度上,地球上动植物的形态以及习性都是由外部环境所塑造的。考虑到地球上生命存在的整个时间,相反作用,即生命对其周围环境的实际改变作用,却相对很小。只有在当前这个世纪(指20世纪)才有一个物种--人类,获得了强大的力量,改变了其所生存的世界的自然状态。
在过去的1/4世纪中,这种力量不仅日趋强大,而且其性质也发生了变化。在人类破坏环境的种种行为中,最令人担忧的是人类向大气、土壤、河流以及海洋中排放危险甚至致命物质,而当今这种污染在很大程度上是无法挽救的。在当今这种对环境的普遍污染中,化学制品与辐射狼狈为奸,改变着地球的自然状态,也就是改变着地球上生命的自然状态。喷洒到农田、森林或者花园里的化学物质长期滞留于土壤中,渗入有机体内,并彼此相传,形成了一个中毒与死亡的链条。化学物质还神秘地通过地下水传递,最终以新的形式出现并结合,使植物毒死,牲畜害病,并使饮用一度纯净的井水的人遭受了不明之害。正如一位科学家所言:?人类甚至对自己创造的恶魔都不认识。?
地球历经了许多亿年才创造了栖息其上的生命。经过了一定时间--不是以若干年计而是以若干千年计的时间--生命开始适应环境,并形成了一种与环境的平衡。但是在现代世界中,时间这一因素已经没有了。
环境改变的速度不再顺从大自然从容不迫的节奏,而是顺从人类急切匆匆的步伐。辐射是当今人类通过支配原子而得到的一种非自然的创造物。化学制品则是人类有发明创造力的头脑创造出来的合成物,在自然界本无相应的东西。
为了适应这些化学制品,人类需要付出的时间不会只是一个人一生的时间,而是几代人的时间。而即使这样,就算出现奇迹成为可能,这种适应也是徒劳的,因为新的化学制品从我们的实验室中源源不断地涌出。仅在美国,每年就有大约500种化学制品投入使用,其中许多是用于人类对自然的战争中。从20世纪40年代中期起,人类已经创造了200多种基本化学制品用来消灭昆虫、野草以及其他所谓的?有害生物?。
我不是说人类决不能使用化学杀虫剂。我要说的是,我们不分青红皂白地将这些有毒的、具有强大生物功能的化学制品,交给了那些对这些制品的潜在危害基本上或者完全无知的人去使用。我们使众多的人接触这些有毒物质,却没有征得他们的同意,并常常将他们蒙在鼓中。我还要说的一点是,我们允许使用这些化学制品,却事先很少或者根本没有调查它们对土壤、水、野生生物以及人类自身造成的影响。我们缺乏对万物赖以生存的自然界生态统一的关心,对此,我们的后代是不可能原谅的。
科普类英语文章
基因技术能否使人更聪明?Get Smart
Many people dream of having a smarter brain. Princeton neurobiologist Joseph Z. Tsien found the key. In September he announced that he?d built a better mouse by altering a gene that affects learning and memory. A similar process of gene manipulation might conceivably be used one day to boost intelligence in humans.
The secret lies in a feature of brain cells called the nmda receptor, which Tsien likens[1] to a cylindrical tube or window that mediates[2] the flow of information. When the window is open, chemicals called neurotransmitters flow through easily and memory is registered and stored. But as organisms mature, the window begins to close. (This may explain why children lose their facility for learning new languages when they reach sexual maturity and why some people suffer memory loss as they age.)
Tsien noticed that the receptor worked more efficiently when teamed[3] with the gene NR2B, so he introduced extra NR2B genes into a batch of fertilized mouse eggs. In a normal mouse, the memory window is open for just 150-thousandths of a second. In Tsien?s specially engineered mice, the window opens for 250-thousandths of a second, long enough to make a remarkable difference in memory retention. When he pitted[4] his mice against common mice, they won paws down. Ordinary mice could recognize a Lego block for 12 hours, but smart mice could remember the block for up to three days. "That?s a profound enhancement," Tsien says.
Can it be done with humans? Maybe, but genetic engineering will have to make some extraordinary advances first. And some thorny ethical issues will have to be resolved. Meanwhile, Tsien promises to keep his furry little geniuses locked up in a lab, far from your larder. "Otherwise," he says, "you might need a smart cat or a smart mousetrap to catch them."
许多人都希望自己能变成更聪明。普林斯顿神经生物学家Joseph Z. Tsien就找到了这把开启智慧之门的钥匙:他于九月宣布,通过改变影响学习和记忆能力的基因培养出了一只聪明的老鼠。类似的基因处理技术有望在未来日子里运用到人脑,以推动人类智慧的飞跃。
该技术的奥秘就在于名为nmda感受器的脑细胞的功能。Tsien将其比作一个传递信息流的圆柱通道或窗口。当窗口开放时,某种称为神经传递素的化学物质就能轻易流过,记忆因此登记并存储了下来。然而,当器官成熟时,这扇窗口就开始关闭。(这也能解释为何 儿童 长大后(性器官成熟之时)会失去掌握新语言的能力,以及为何某些人年老时会患失忆)。
Tsien注意到,当感受器与名为NR2B的基因协作时效率会更高。因此,他将NR2B基因植入一批老鼠的受精卵中。一只普通老鼠的记忆之窗仅开放千分之150秒。而经Tsien植入基因的老鼠,记忆之窗能开放千分之250秒,这已经能够使其 记忆力 发生惊人的改变。当他让自己的老鼠与普通老鼠互斗时,它们竟能轻而易举地取胜。普通老鼠能够保留关于Lego block的记忆12小时,而聪明的老鼠居然能将记忆保持三天。?这可是一个意义深远的进步。?Tsien这样说。
那么,人类也能接受这种基因移植吗? 或许可以,但前提是基因工程得首先做出非凡的成就,还必须解决一系列棘手的伦理问题。Tsien保证他一定会将那些披着毛皮的小天才锁入实验室,远离人们的食品柜。?否则,?他说,?为了捉住他们,人们就不得不去寻找更聪明的猫或者功能更强的捕鼠器了。?
科普类英语文章
食用转基因食品安全吗?Food Safe To Eat?
Traditional plant breeding involve s crossing varieties of the same species in ways they could cross naturally.For example,disease-resistant varieties of wheat have been crossed with high-yield wheat to combine these properties.This type of natural gene exchange is safe and fairly predictable.
Genetic engineering(GE)involves exchanging genes between unrelated species that cannot naturally exchange genes with each other.GE can involve the exchange of genes between vastly different species――e.g.putting scorpion toxin genes into maize or fish antifreeze genes into tomatoes.It is possible that a scorpion toxin gene,even when it is in maize DNA,will still get the organism to produce scorpion toxin――but what other effects may it have in this alien environment?We are already seeing this problem――adding human growth hormone genes to pigs certainly makes them grow――but it also gives them arthritis and makes them cross-eyed,which was entirely unpredictable.
It will be obvious,for example,that the gene for human intelligence will not have the same effect if inserted into cabbage DNA as it had in human DNA――but what side-effect would it have?In other words,is GM food safe to eat?The answer is that nobody knows because long-term tests have not been carried out.
Companies wanting a GM product approved in the UK or USA are required to provide regulatory bodies with results of their own safety tests.Monsanto?s soya beans were apparently fed to fish for10weeks before being approved.There was no requirement for independent testing,for long-term testing,for testing on humans or testing for specific dangers to children or allergic people.
The current position of the UK Government is that? There is no evidence of long-term dangers from GM foods.?In the US,the American Food and Drug Administration is currently being prosecuted for covering up research that suggested possible risks from GM foods.
传统的植物培育 方法 ,是依照植物自然杂交的方式,进行相同物种的人工杂交。比如,抗病小麦同高产小麦杂交,形成了一种具有双重特性的新的小麦品种。这种自然的基因交换既安全,又具有相当的可预见性。
基因工程是在彼此毫无关系的物种之间,相互交换在自然条件下无法交换的基因。它可在有巨大差异的物种之间进行基因交换。比如,将蝎子毒素基因注入玉米,或者将鱼防冻基因注入西红柿。即使在玉米DNA中,蝎子毒素基因依然可能获得有机组织产生蝎子毒素。但是在这种异质的环境中,这种基因产品会有什么其他作用吗?我们实际上已经发现这个问题:将人类生长荷尔蒙基因植入猪的体内,一定会使猪的生长加速,但是同时也使猪患上了关节炎和内斜视,而这一切是完全无法预测的。
打个比方,人类的智力基因显而易见在人体DNA内和注入卷心菜DNA后的作用是不同的。但将它植入卷心菜中会产生什么样的副作用呢?换句话说,食用转基因食品安全吗?没有人知道答案,因为人们尚未进行长期的测试。
在英国或者美国,一个公司如果希望其转基因产品获得批准,它必须向管理机构提供本公司转基因产品安全测试的结果。Monsanto的大豆在获得批准之前,曾用了10周时间进行喂鱼试验。目前,尚无要求对转基因产品进行独立测试、长期测试、人体测试,或者就其对儿童及过敏者所造成的特定危险进行测试。
英国政府目前的态度是:?尚无证据表明食用转基因食品存在长期性的危险。?在美国,人们正在起诉美国食品药品管理局掩盖转基因食品安全性的研究结果,这些研究结果表明,食用转基因食品可能导致危险。
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