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吉安市第一人民医院做双眼皮手术多少钱泰和县人民中医院韩式三点多少钱Penrose announced this result that when stars collapse indefinitely.当时彭罗斯告诉我这个结论 当恒星无限坍缩时they will become singular as long as some very broad conditions are satisfied他们会变得奇异 只需要满足一些很宽松的条件就会这样that everybody would have regarded as reasonable.很多人都同意这一点And I remember Stephen Hawking, who was then approaching我记得史蒂芬·霍金当时快要三年级了his third year as a research student, saying What very interesting results.他还是研究生 他说 多有趣的结果;I wonder whether they could be adapted to understanding the origin of the universe.我很好奇是否能应用它们 来理解宇宙的起源And what he had in mind, you see, was that if, just mentally you reverse the sense of time.他脑子里想的是 如果你像这样想像 让时光倒流you can think of the expanding universe as a collapsing system.那么这个正在膨胀的宇宙就会变成一个坍缩中的系统Its a bit like a very giant star collapsing.这就像一个异常巨大的恒星正在坍缩Roger Penrose proved that a dying star, collapsing under its own gravity.罗杰·彭罗斯明了 一个垂死的恒星会在其自身重力的作用下坍缩eventually shrinks to a singularity a point of infinite density and zero size.最后变成一个奇点 一个拥有无穷大密度而没有体积的点I realized that if I reversed the direction of time so that the collapse became an expansion.我意识到 如果我颠倒时间进行的方向 那么这个坍缩的过程就变成膨胀I could prove that the universe had a beginning.于是我就能明 宇宙确实是有起源的But my proof based on Einsteins theory of general relativity然而 我的明 是建立在爱因斯坦广义相对论的基础上also showed that we cannot understand how the universe began.这同时也表明我们无法理解 宇宙究竟是如何起源的because it showed that all scientific theories including general relativity itself break down at the beginning of the universe.因为它表明 所有的科学理论 包括广义相对论本身 都会在宇宙起源时分崩离析201604/435379吉安保仕柏丽整形美容医院激光祛痣多少钱 This presentation will examine what food additives are本讲将介绍何为食品添加剂and if these ingredients are safe to be in our food.以及这些添加剂在我们的饮食中是否安全What exactly is a food additive?到底什么是食品添加剂呢?Technically a food additive is anything that you add to your food,学术上认为食品添加剂是任何加入食品中的物质but legally food additives have a different definition.但法律上的食品添加剂概念不同Lets take a look.来看一下Legally the term refers to any substance法律上该词条指where the intended use of which results directly or indirectly in its becoming a component有意地加入到食品中使之直接或间接地成为食品成分or otherwise affecting the characteristic of any food.或者影响食品特征的物质This definition includes any substance used in the production,这一词条包含在产品生产,processing, treatment, packaging, transportation or storage of food.加工,处理,包装,运输和储存的任何物质Basically its anything we add to our food whether it is to preserve it, add colour or flavour.基本上它指我们加入食品的任何物质,无论是为了食品的储存,上色还是味道的提升And can you name a common food additive?你能够指出常用的食品添加剂么?So why do we even use additives?我们为什么会使用添加剂呢?We use additives to preserve safety and freshness of food是为了维持事物的安全新鲜to add nutritional value and to improve food quality.增加食物的营养价值,提升食品质量For safety and freshness, mold, air, bacteria, fungi or yeast can easily ruin food without additives.在保持食物的安全新鲜上,霉菌,空气,细菌,真菌和酵母很容易使不含添加剂的食品变质Which is why we add them to food to give a longer shelf life and to keep the product fresher longer.因此添加剂的放入能够使食品贮存时间,保持新鲜的时间更长They can also help prevent fats and oils from becoming rancid and giving the product off flavour.添加剂还能够防止油脂腐臭而导致食物变味Another very important use is in the prevention of添加剂的另一重要用途是food borne illnesses and contamination and then for nutritional values.防止食源性疾病和污染,提升食物营养价值Its very common for a lot of our food to be fortified to add nutritional components我们的很多食物中都加入其在加工过程中流失的营养成分,that are lost in the processing or are insufficient in our pipeless diet.或饮食中缺乏的营养成分,这是极为平常的Adding nutrients to our food has helped to食品中加入添加剂能够prevent vitamin and mineral deficiencies and prevent malnutrition.补充维生素矿物质并避免营养不良All products containing extra nutrients can also be found on the label.我们能够在所有食物标签中找到添加的营养物质With regard to improving food quality关于提升产品质量方面natural artificial flavourings, coulour, spices and sweeteners are added to food人造食用香料,颜料,调味料和甜味剂都加入食品中to give the foods a better flavour texture and appearance.以保食品味道鲜美,质构精良,外观宜人Things that help to improve quality would be emulsifiers提升食品质量的叫做乳化剂which add stability and thicken products.它能够增加食品的稳定性,稠化食品An example of this would be egg yolks which are commonly used as emulsifiers in various products.比如蛋黄,它就在各种食品中充当乳化剂成分Additives can also help to preserve the acidity or alkalinity of a product to help prevent spoilage.添加剂能够帮助保持食物的酸碱度,从而使其不易腐烂201601/424353The most likely explanation is probably that we are an accident.最可能的解释就是,也许我们的存在只是一次意外Just by chance, some molecules bumped into each other at random机缘巧合下,一些分子随机地进入其他分子until finally one formed that could copy itself.直到最后组合了一个可以自我复制的个体Then began the slow process of evolution接着,缓慢的进化过程开始了that led to all the extraordinary diversity of life on Earth.这形成了地球上生命的多样性Life seems to be simply只要有适宜的环境what matter does given the right conditions and enough time.和充足的时间,物质似乎就能构成生命I think that life is probably quite common throughout the universe,我认为生命遍及整个宇宙but thats another tale all together.不过那是另外一个故事了As life developed, it changed the planet on which it was born,生命在演替的同时,也改变着育它的星球altering the very fabric of the Earth.改变着地球特有的构造After four and a half billion years, the human race arrived on the scene.45亿年后,人类登场了But one thing often troubles people when they hear this story.但人们听这故事时,常常被一个问题困扰How could such an astounding chain of events一系列导致我们出现的事件which resulted in us be an accident?怎会仅出于偶然Perhaps science has revealed there is some higher authority at work,或许科学已经揭示还有更高等的权威在运作setting the laws of nature so that our universe and we can exist.制定自然法则,使宇宙和我们得以存在On the face of it,乍看起来 life does seem to be too unlikely to be just a coincidence.生命的出现不太可能是巧合Think about it.仔细想想The Earth lies at exactly the right distance地球恰好与太阳距离适当from the sun to allow liquid water to exist on its surface.使地表能够存在液态水And the sun just happens to be the right size而太阳也恰好大小适中to burn for billions of years long enough for life to have evolved.足以燃烧数十亿年,足够生命得以进化The solar system is littered with all the elements needed for life.太阳系中充满生命所需的所有元素These elements themselves are only possible只有古老恒星消亡because of older stars that have burned out.这些元素才能产生These older stars only existed而只因为早期原始气团的微不均匀because of a tiny unevenness in the early primordial gas,这些古老恒星才能存在that was itself produced by a one in a billion imbalance它自身源于大爆炸产生的粒子海洋中in the sea of particles that came from the Big Bang.十亿分之一的不平衡201509/400880吉安妇保医院做双眼皮开眼角多少钱

井冈山市中医院修眉多少钱吉州区隆下巴多少钱 TED演讲集 那些匪夷所思的新奇思想201512/415899吉安吸脂哪里好

吉安市保仕柏丽整形医院打瘦脸针多少钱SETI(寻找外太空星球智慧生命计划)的Jill Tarter于此许下她的TED大奖愿望:加快我们对宇宙同伴的搜寻。利用不断增加的无线电望远镜,她和她的组员们倾听着可能是从宇宙另一处文明所发出的信号。201504/367569 If you were watching an astronaut foolhardy enough to jump into a black hole如果你观察一名宇航员 莽撞地跳进一个黑洞at some time on his watch say, 12:00 he would cross the event horizon and enter the black hole.这时候他手表上的时间是 比如说 12点 他接下来穿过事件视界 然后进入黑洞But no matter how long you waited you would never see the astronauts watch reach 12:00.可是不论你等多久 你都永远不会看到他的手表走到12点Instead, each second on the watch would appear to take longer and longer理论上发生的是 手表上的每一秒 都会看起来越来越长until the last second before midnight would take forever.直到午夜前的最后一秒 它会持续到永远Thus, by jumping into a black hole one could ensure that ones image lasted forever.因此 如果一个人要跳进黑洞 他可以肯定 自己的形象会永远存在But the picture would fade very rapidly and grow so dim that no one could see it.但图像会迅速地消逝 并且变得模糊不清 谁都看不见As somebody disappears into a black hole as seen from the outside, it looks as though当一个人消失在黑洞中时 如果从外面观察 就会发现time actually slows down, and the person whos moving at least hes thinking hes moving时间似乎变慢了 这个移动着的人 至少他认为自己在移动hes perhaps talking in his spaceship at a normal rate seems to slow down and ends up being frozen他也许正在飞船中以正常的语速讲话 但听起来是变慢了 最后在某一个特定的位置in a particular position as seen by somebody watching him from the outside.被冻结起来 从视界外观察就是如此And as seen from the outside, you never see what happens after that.而且你永远不会看见他冻结之后发生的事情The astronaut wouldnt notice anything special when his watch reached midnight.那个宇航员自己 则什么都不会注意到 当他的手表到达午夜时And he crossed the event horizon into the black hole他就穿过视界 进入黑洞until, of course, he approached the singularity and was crushed into spaghetti.直到他最终抵达奇点 被挤成肉泥201604/436213吉安抽脂医院哪家好永新县丰胸多少钱



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