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2019年12月08日 23:57:40 | 作者:预约生活 | 来源:新华社
If you get caught in the middle of a big,open field during a lightning storm,Which of the following uniforms would be most likely to keep you safe?A thick wetsuit;a superman costume;a medieval coat of armor;or a birthday suit?If you answered;medieval coat of armor,;you might be a little crazy-but youd also be right.如果你在暴风雨中被困在了一个大空地的中央,下面那套衣最可能让你活命?一套厚雨衣,超人外套,中世纪盔甲套装, 还是一丝不挂?如果你说“中世纪盔甲套装”听上去可能有些疯狂,不过你是对的。Youd be crazy,of course,because lightning is much more likely to strike metal than to strike rubber,afbric,or bare skin.The reason is that lightning bolts are just long streams of fast-flowing electrons looking for the easiest path from point A to point B,and no everyday material provides an easier path than metal.So why would a material that lures lightning bolts keep you safe during a thunderstorm?当然,这的确很疯狂,因为与橡胶,布或者的皮肤相比,闪电更容易击中金属。这是因为闪电其实是一长束快速流动的电子,它寻找着从A点到B点的最易路径,常见的材料在制造最易路径上都比不上金属。那么为什么吸引闪电的材料,却能在暴风雨中让你更安全?Ironically,for the exact same reason it attracts the the lightning in the first place:Metal is a great conductor of electricity.Electrons glide so easily over metals that they barely penetrate into the surface.And if an electrical current happens to be moving over a hollow metal container,like a can or a box or even a welded coat of armor,the current wont reach the inside of the container.讽刺的是,亦正出于这个原因,它首先会吸引闪电:金属是电的良导体。电子在金属内部流动十分顺畅,它们很少穿到金属表面。如果电流恰好流过一个中空的金属容器,比如一个罐子,盒子甚至一套盔甲,电流并不会触及容器内部。Physicists call this kind of container a Faraday cage.Or,in the case of the steel-woven clothing worn by linemen working on high-voltage wires,a Faraday suit,In fact,your car is an everyday example of a Faraday cage,which is why,despite what you may have heard about rubber tires,its actually the closed metal body surrounding you that keeps you safe.It channels lightning around,rather than through you.物理学家称这样的容器为,法拉第笼。或者,那些工作在高压线上的,布线工人身上穿的钢丝编织的衣,法拉第。实际上,你的车就是一个常见的法拉第笼,这就是为什么,即便你可能听说过橡胶轮胎的作用,但其实,正是你周围的钢铁骨架在保护你的安全。它将闪电导向周围,而不穿过你身体。Of course,if youre away from your car and get caught in an open field during a storm,chances are flim that youll have a medieval coat of armor or high voltage line-suit handy.In that case,whether youre naked or in costume,your body unfortunately happens to be a better electrical conductor than both air and soil,so it provides a great shortcut for traveling current.当然,如果暴风雨来临时,你被困在空地,身边没有车,你手头也很可能有世纪盔甲或者高压。在这种情况下,无论你穿没穿衣,很不幸,你的身体恰巧比空气和土地的导电性更好,这就为流动的电流创造了良好的捷径。Stand upright,and youre the fastest route for a descending lightning bolt.Lie down,and youre the best path for current racing along the ground from a nearby strike.So the best thing to do is crouch low and keep your feet close together.Crouching low is obvious.But similarly important,when your feet are right next to each other,your legs dont make for much of a shortcut for the current to get from A to B.直立时,你成为了闪电劈下时的最快路径。躺下时,你是附近闪电击地时 电流流过地面的最佳路径。最好的办法是蹲下身子,双脚尽量靠在一起。蹲下身子很好理解。但同样重要的是, 当你的双脚紧靠在一起时,你的双脚并不会构成让电流从A点流到B点的捷径!And even if they are the best path for the lightning,when your feet are the only thing touching the ground,then the current will most likely travel up one leg and down the other,missing critical organs like your heart-something these cows couldnt avoid.同时 即使它是了闪电的最佳路径,在你仅用双脚接触地面的时候,电流很可能从一条腿流上去,再从另一条流下来,避开了心脏等关键器官,而牛却没法避免这种事。But,actually,the real best thing to do is avoid lightning altogether and head indoors when you spot a storm on the horizon.不过,其实,最好的方法是从根本上躲开闪电 在你看到远方的暴风雨时躲到室内。201502/357378Alibaba chairman: Chinese market promises huge potential阿里巴巴董事长表示中国市场潜力巨大The first Double Eleven Shopping Festival started in , when online sales platform Tmall started its nationwide sales campaign.第一次的双十一购物节从年开始,当时在线销售平台淘宝商城开始在全国举行促销活动。Now, consumers in more than 200 countries and regions can choose from 6 million different goods.现在,超过200个国家和地区的消费者可以从600万种不同的商品中选购。Chairman of Alibaba group Jack Ma says the Chinese market promises huge potential.阿里巴巴集团董事局主席马云表示中国市场呈现出巨大潜力。 译文属201511/409478栏目简介:《外国人在北京》是英语视频听力下面的子栏目,节目关注在北京生活的外国人的时尚新生活。话题紧紧围绕网络生活,每日的话题内容按照网络热门固定划分为家居、汽车、数码、饰美容、健身、交友、美食等,了解外国人生活的同时通过网络互动提供一个中外人士互相帮助的平台。201603/407659

Adding to the misery of thousands of migrants blocked at the Greek-Macedonian border.封锁在希腊马其顿边境成千上万的移民雪上加霜。Heavy rain has flooded parts of the makeshift camp where up to 12,000 people have sought refuge.暴雨淹没了部分临时营地,多达12,000人寻求避难。Children and the elderly are among those living in cold and difficult conditions.儿童和老年人也生活在寒冷和困难的条件下。This is full of water, so the people come here, and seven persons, and our bucket is full of water, so it’s so cold.这里到处是水,人们来到这里,七个人,我们的桶里装满了水,非常的寒冷。And you see our clothes, all of this full of water because we didn’t have a place.你看看我们的衣,到处是水因为我们没有容身之地。Those affected by the flooding have tried to salvage what they can of their few possessions.那些受洪水影响的人试图挽救他们那点仅剩的财产。You can swim and sleep at the same time.你可以一边游泳一边睡觉。Only a handful of migrants are being let through the border every day, causing a long agonising wait for those seeking asylum.每天只有少数移民被允许通过边境,那些寻求庇护的人经历漫长痛苦的等待。The images here are coming to symbolise the migrant crisis in Europe and the failure to find adequate solutions.这里的场景象征着欧洲移民危机,并没有找到适当的解决办法。译文属。 /201603/429516

The educational materials presented here今天展示的教育材料were developed by students and faculty是由爱荷华州立大学营养学of the department of food science and human nutrition和人体营养学系的at Iowa State University.学生和老师提供的Funding for this project was provided by grants该项目的资金由from the American Cancer Society Mid West美国中西部地区癌症协会and the Lance Armstrong Foundation.及兰斯,阿姆斯斯壮基金会提供The materials are intended for educational use这些材料仅用于教学and are not meant to provide medical advice.并非用以提供医疗指导We welcome your feedback about these materials.欢迎大家对这些材料做出反馈Please use the evaluation survey link on the homepage请用主页上提供的调查评价链接to provide your comments and suggestions.提交你们的和建议The markets are full of dietary supplements市场上充斥着很多补品and it is difficult to know which, if any, might be useful很难辨别哪个也许有用to promote health, resist disease or improve wellbeing.可以促进人体健康,抵御疾病,提高身体素质This presentation will outline the basic information今天的演讲会提供about dietary supplements有关补品的基本信息and provide helpful information也会提供一些实用的信息about their contributions to a healthy lifestyle.说明补品对健康生活方式的贡献A supplement is intended to supplement the diet.补品的用途在于补充膳食The main feature of a supplement一种补品的主要特征是is that it is very different from a food.它与食物大不相同It contains one or more ingredients such as a vitamin,它含有一种或多种营养成分,例如维他命mineral, botanicals or herbs and is intended to矿物质,草本植物,草药等,它是用来be taken orally in pill, capsule, liquid or tablet form.口的,有丸剂,胶囊剂,液体剂或者片剂等Supplements are labeled as supplements补品一般都会在其商标说明上注明on the front panel. In the picture shown here从这张图片大家可以看到you can see that this particular vitamin supplement这种补品included calcium and vitamin D含有钙和维他命Dwhich are 2 ingredients and it is taken orally这两种营养成分,用方法是口in the form of a tablet and it is labeled as补品是片剂形式,商标上注明了a supplement on the front panel.它是一种补品Vitamin and mineral supplements维他命和矿物质补品have been available to consumers for over 100 years.消费者已经使用了100多年了These products are typically mixtures这些补品主要是混合物of known essential nutrients in quantities由一些大家熟知的常规营养物构成defined by the national academy of sciences由美国国家科学院的院士们命名and the recommended dietary allowances还有推荐的膳食营养素供应量or the RDA. The label on these supplements或被称为RDA,这些补品上的商标defines the percent of the RDA that is met by都注明了RDA的百分比,一般是1 of the dose of the product. In general用补品的一剂,一般来说vitamin and mineral supplements are safe用维他命和矿物质补品是安全的to be consumed when they contain around 100%条件是它们含有大概100%的RDAof the RDA. Supplements with much more than补品RDA超过这个值的the RDA, 200% or greater, are not necessary比如达到200%或者更高,就不必要了and may cause toxicity.这也许还会产生毒性So when are vitamin supplements advisable?所以什么时候用维他命补品比较合适呢Vitamin B12 supplements are advisable for individuals维他命B12适用于那些over the age of 50 who have trouble50岁以上,并且很难absorbing this vitamin naturally.自然吸收这种维他命的人Folic acid supplements may be advisable维生素B适用于to women who may become pregnant快要怀or are pregnant in order to decrease the likelihood或已经怀的女性,这样可以降低怀有of having a baby with neural tube defects.一个神经管畸形婴儿的风险Vitamin D supplements are also advisable to individuals维他命D适用于who do not get enough exposure to the sun那些很少晒太阳and who do not get enough vitamin D而且没有吸收足够维他命D的人through fortified product. Calcium is sometimes尽管他们食用了富含维他命D的食物,钙比较also advised for bone health in mostly women.适用于大多数女性,可以促进骨骼健康Herbal supplements are different than vitamin草药补品与维他命and mineral supplements because there are no和矿物质不同,因为没有known requirements for herbal compounds标准规定用哪些草药补品to maintain health. This means that以保持身体健康,也就是说there is no RDA for herbal ingredients.草药补品没有规定的RDAHerbal supplements are mixed with compounds草药补品是由化合物混制的derived from plants and algae这些化合物提取自植物和藻类that some supplements may also contain ingredients这些植物和藻类也许还含有from animal sources such as fish oil动物身上如鱼油or pancreatic extracts.或胰腺中的养分Our understanding of herbal supplements我们对草药补品的认识is derived form traditional medicine practices来自多年来很多of many civilizations for many, many years.文明的传统医学In these cultures healers use在这些文化中,医生使用naturally occurring products to treat ailments天然药物来医治疾病and out of these practices modern medicine arose.现代医药就来自这些实践All dietary supplements sold in the US美国销售的所有补品must comply with strict labeling laws.必须严格遵守商标法On the front panel the label must include商标必须附有a statement of identity indicating the composition补品合成物的说明of the product and the net quality of contents.以及各成分的净重The label also must contain a list of ingredients商标还应包括某一种补品的成分in a particular supplement and other ingredients并且降序标出in descending order of pre dominance其他主要营养成分and by common name or proprietary blend.用其通用名称或者专利合成名201502/359327



The results reveal the extraordinary effect实验结果揭示 烹煮过的食品that cooking food has on easing its way through the snakes body.确实更易被蟒蛇吸收 并产生重大影响So when we feed the python a ground, cooked steak我们发现消化搅碎后的熟牛排we find that the energy expended on digestion assimilation所消耗的能量 比消化未加工的生牛排has decreased by 24% compared to the intact, raw steak.所消耗的能量少24%The figure has huge significance.这个数字非常重要It shows that eating cooked food reduces by a quarter它告诉我们 吃熟食比吃生食the energy required to carry out the process of digestion.消耗的能量要少四分之一Professor Wrangham claims that this extra energy朗汉教授称这些多余的能量caused the dramatic adaptations in Homo erectus.使直立人发生重大适应性变化Cooking made our guts smaller.烹饪使我们的肠道变小Once we cooked our food,我们烹饪食物后we didnt need big guts,就不需要大肠胃去消化and big guts were a disadvantage...大肠道对于我们很不利theyre costly in terms of energy.它们消耗的能量较多So those individuals that were born with small guts那些生来具有小肠胃的个体were able to save energy and therefore have more babies and survive better.才能节约能量 从而生育更多后代并活得更好201506/378420

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