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JimHudspeth_2019S-_听觉背后美丽而神秘的科学_-
Can you hear me OK? 各位可以听到我的声音吗？
Audience: Yes. 观众:可以。
Jim Hudspeth: OK. Well, if you can, it's really amazing, because my voice is changing the air pressure where you sit by just a few billionths of the atmospheric level, yet we take it for granted 吉姆 · 赫兹佩斯:好的。 如果你能听见,那真是不可思议。 因为我的声音会改变你身边的气压, 改变程度只有大气压的 几十亿分之一而已, 但我们都理所当然地觉得
billionths:adj.十亿分之一的;第十亿的;n.十亿分之一;第十亿; atmospheric:adj.大气的,大气层的; take it for granted:认为理所当然;想当然;
that your ears can capture that infinitesimal signal and use it to signal to the brain the full range of auditory experiences: the human voice, music, the natural world. 耳朵能捕捉到这个 微乎其微的信号, 并将丰富的听觉体验传递给大脑: 人声,音乐,大自然的声音。
capture:v.俘虏;捕获;攻占;夺得;刻画,描述;n.(被)捕获;(被)俘获 infinitesimal:adj.无穷小的;无限小的;极小的;n.无限小;极微量;极小量; auditory:n.听众;礼堂;adj.听觉的;耳朵的;
How does your ear do that? 你的耳朵是怎样做到的呢？
And the answer to that is: through the cells that are the real hero of this presentation -- the ear's sensory receptors , which are called "hair cells." 答案就是: 通过细胞,也是本次演讲 真正的主角—— 耳朵的感觉接收器, 被称为“毛细胞”。
presentation:n.展示;描述,陈述;介绍;赠送; sensory:adj.感觉的;知觉的;传递感觉的; receptors:n.[生化]受体;接受器;神经末梢(receptor的复数);
Now, these hair cells are unfortunately named, because they have nothing at all to do with the kind of hair of which I have less and less. 毛细胞虽然叫毛细胞, 但和我头顶越来越少的“毛” 一点关系都没有。
unfortunately:adv.不幸地;
These cells were originally named that by early microscopists, who noticed that emanating from one end of the cell was a little cluster of bristles . 早期的显微镜学家发现, 这些细胞的一端长有一小撮纤毛, 毛细胞的名字便由此而来。
originally:adv.原来;起初; emanating:从...处传出,传出(emanate的现在分词); cluster:n.群;簇;丛;串;vi.群聚;丛生;vt.使聚集;聚集在某人的周围; bristles:n.猪鬃(bristle的复数形式);v.毛发直立(bristle的三单形式);
With modern electron microscopy , we can see much better the nature of the special feature that gives the hair cell its name. 有了现代的电子显微镜, 我们能更清楚地看见 让毛细胞得名的这个特征的细节,
electron:n.电子; microscopy:n.显微镜检查;显微镜使用;显微镜学;
That's the hair bundle . 那是毛束。
bundle:n.包; v.匆匆送走; (成群地)匆忙赶往;
It's this cluster of 20 to several hundred fine cylindrical rods that stand upright at the top end of the cell. 它由二十到几百个 纤细的圆锥形小杆组成, 直立在细胞的顶端。
cylindrical:adj.圆柱形的;圆柱体的; rods:n.鱼竿(rod的复数);棒条体;v.装避雷针;用杆捅清(rod的单三形式); upright:n.立柱;adj.直立的;挺直的;竖直的;垂直的;adv.竖立着;垂直着;
And this apparatus is what is responsible for your hearing me right this instant . 正是这个器官, 让你此刻能听见我说话。
apparatus:n.装置,设备;仪器;器官; responsible:adj.负责的,可靠的;有责任的; instant:n.瞬间; adj.立即的; conj.同"assoonas";
Now, I must say that I am somewhat in love with these cells. 不得不承认,我对这些细胞 多少有些着迷。
somewhat:n.几分;某物;adv.有点;多少;几分;稍微;
I've spent 45 years in their company -- 它们陪伴了我 45 年——
(Laughter) （笑声）
and part of the reason is that they're really beautiful. 原因之一是它们非常美丽,
There's an aesthetic component to it. 有一种美感。
aesthetic:adj.美的;美学的;审美的,具有审美趣味的; component:n.成分;部件;组成部分;adj.构成的;
Here, for example, are the cells with which an ordinary chicken conducts its hearing. 比如说,这是一只普通的鸡 用来听声音的细胞。
conducts:vi.导电;带领;vt.管理;引导;表现;n.进行;行为;实施;
These are the cells that a bat uses for its sonar . 这些是蝙蝠的声呐细胞。
sonar:n.声纳;声波定位仪(等于asdic);
We use these large hair cells from a frog for many of our experiments. 我们在许多实验中都采用 这些取自青蛙的大型毛细胞。
Hair cells are found all the way down to the most primitive of fishes, and those of reptiles often have this really beautiful, almost crystalline , order. 一直到最原始的鱼类中, 都能发现毛细胞的身影, 而爬行动物的毛细胞 通常呈现出这种非常美丽的、 近乎晶体状的有序结构。
primitive:adj.原始的,远古的;简单的,粗糙的;n.原始人; reptiles:n.爬行动物(reptile的复数);[脊椎]爬行类;爬虫类; crystalline:adj.透明的;水晶般的;水晶制的;
But above and beyond its beauty, the hair bundle is an antenna . 但除去它的美丽不提, 这个毛束是一根天线。
antenna:n.[电讯]天线;[动]触角,[昆]触须;
It's a machine for converting sound vibrations into electrical responses that the brain can then interpret . 它是一台将声音振动 转换成电学信号的机器, 大脑随后可以破译这些电信号。
converting:v.(使)转变,转换,转化;可转变为;归附;(convert的现在分词) vibrations:n.[力]振动;共鸣;动摇(vibration的复数); electrical:adj.有关电的;电气科学的; responses:n.回答,答复;反应;响应;(response的复数) interpret:v.诠释;说明;口译;把…理解为;
At the top of each hair bundle, as you can see in this image, there's a fine filament connecting each of the little hairs, the stereocilia. 在这张图里能看到, 在每一簇毛束的顶上, 都有一根纤细的丝,把每根叫做静纤毛 的小纤毛连接起来
as you can see:正如你所看到的;你是知道的; filament:n.灯丝;细丝;细线;单纤维;
It's here marked with a little red triangle . 就是红色小三角所指的地方。
triangle:n.三角形;三角形物体;三角铁(打击乐器);三角关系;
And this filament has at its base a couple of ion channels, which are proteins that span the membrane . 这条细丝的根部 有若干个离子通道, 就是一种跨越细胞膜的蛋白。
proteins:n.[生化]蛋白质(protein复数); span:n.持续时间; v.持续; membrane:n.膜;薄膜;羊皮纸;
And here's how it works. 它的工作原理是这样的。
This rat trap represents an ion channel. 这个“捕鼠夹”代表了一个离子通道。
trap:v.使陷入困境;卡住;夹住;收集;吸收;n.陷阱;圈套;捕捉器;诡计; represents:v.代表;维护…的利益;相当于;(represent的第三人称单数)
It has a pore that passes potassium ions and calcium ions. 它有个开孔, 能让钾离子和钙离子通过。
pore:vi.细想;凝视;熟读;n.气孔;小孔;vt.使注视; potassium:n.[化学]钾; calcium:n.[化学]钙;
It has a little molecular gate that can be open, or it can be closed. 它有个小小的分子门, 可以打开,也可以关上。
molecular:adj.[化学]分子的;由分子组成的;
And its status is set by this elastic band which represents that protein filament. 它的状态是由这根代表了 蛋白连接丝的橡皮带设定的。
status:n.地位;状态;情形;重要身份; elastic band:n.橡皮筋;橡皮圈;
Now, imagine that this arm represents one stereocilium and this arm represents the adjacent , shorter one with the elastic band between them. 想象一下,这条手臂 代表了一根静纤毛, 而这条手臂则代表了旁边 更短的一根静纤毛, 它们之间由橡皮带连接。
stereocilium:n.静纤毛; adjacent:adj.邻近的,毗连的;
When sound energy impinges upon the hair bundle, it pushes it in the direction towards its taller edge. 当声音能量冲击到毛束时, 它会将毛束朝更高的一端推动。
impinges:vi.撞击;侵犯;vt.撞击;
The sliding of the stereocilia puts tension in the link until the channels open and ions rush into the cell. 纤毛滑动,使得连接丝中产生张力, 直到通道打开,离子冲进细胞里。
tension:n.张力;拉伸;矛盾;紧张局势(或关系,状况);v.绷紧;
When the hair bundle is pushed in the opposite direction, the channels close. 当毛束被朝反方向推动时, 离子通道就关上了。
And, most importantly, a back-and-forth motion of the hair bundle, as ensues during the application of acoustic waves, alternately opens and closes the channel, and each opening admits millions and millions of ions into the cell. 最重要的是, 声波会让毛束前后来回运动, 离子通道就会交替着 打开、关闭, 每次打开都会让 数以百万的离子进入细胞。
back-and-forth:前后移动的,来回的,反复的; motion:n.动作;移动;手势;请求;意向;议案;v.运动;打手势; ensues:vi.跟着发生,接着发生;继起;vt.追求; application:n.应用;申请;应用程序;敷用; acoustic:adj.声学的;音响的;听觉的;n.原声乐器;不用电传音的乐器; alternately:adv.交替地;轮流地;隔一个地;
Those ions constitute an electrical current that excites the cell. 这些离子形成电流, 让细胞兴奋。
constitute:v.组成;构成;(合法或正式地)成立,设立;
The excitation is passed to a nerve fiber , and then propagates into the brain. 这种兴奋状态被传递给神经纤维, 随后传导进大脑。
excitation:n.激发,刺激;激励;激动; nerve:n.神经;勇气;神经质;神经紧张;v.鼓足勇气;振作精神; fiber:n.纤维;光纤(等于fibre); propagates:vt.传播;传送;繁殖;宣传;vi.繁殖;增殖;
Notice that the intensity of the sound is represented by the magnitude of this response. 这个反应的程度 代表了声音的强度。
intensity:n.强度;强烈;[电子]亮度;紧张; represented:v.代表; (represent的过去式和过去分词) magnitude:n.大小;量级;[地震]震级;重要;光度;
A louder sound pushes the hair bundle farther, opens the channel longer, lets more ions in and gives rise to a bigger response. 更响的声音会把毛束推得更远, 离子通道打开的时间更久, 进入细胞的离子更多, 反应也就更强。
Now, this mode of operation has the advantage of great speed. 这种运行模式的好处是速度极快。
advantage:n.有利条件:优势:优点:
Some of our senses, such as vision , use chemical reactions that take time. 我们的某些感官,比如视觉, 利用的是耗时的化学反应。
vision:n.视力;美景;幻象;想象力;v.想象;显现;梦见; chemical:n.化学制品,化学药品;adj.化学的; reactions:n.反应;回应;抗拒;生理反应;副作用(reaction的复数)
And as a consequence of that, if I show you a series of pictures at intervals of 20 or 30 per second, you get the sense of a continuous image. 因此,如果我以 每秒 20 到 30 张的间隔 给你看一系列图片, 你就会产生看到了 连续图像的感觉。
consequence:n.结果;重要性;推论; series:n.系列,连续;[电]串联;级数;丛书; at intervals:时时,不时;相隔一定距离(或时间); continuous:adj.连续的,持续的;继续的;连绵不断的;
Because it doesn't use reactions, the hair cell is fully 1,000 times faster than our other senses. 因为毛细胞不使用化学反应, 它比我们的其他感官 要快整整 1000 倍。
We can hear sounds at frequencies as great as 20,000 cycles per second, and some animals have ever faster ears. 我们能听到每秒高达 2 万个周期（2 万赫兹）的频率, 而有些动物的耳朵更灵敏。
frequencies:n.频率;发生率;重复率;频繁;(frequency的复数)
The ears of bats and whales, for example, can respond to their sonar pulses at 150,000 cycles a second. 比如说,蝙蝠和鲸鱼的耳朵能探测到它们每秒 15 万个周期 （15 万赫兹）的声呐信号。
respond:vi.回答;作出反应;承担责任;n.应答;唱和; pulses:n.[电子]脉冲(pulse的复数); v.使跳动;
But this speed doesn't entirely explain why the ear performs so well. 但这个速度并不能完全解释 为什么耳朵的性能如此出色。
performs:v.执行;表演;演出;履行(perform的第三人称单数)
And it turns out that our hearing benefits from an amplifier , something called the "active process ." 事实上,我们的听觉 得益于一种扩音器, 它被称为“有源放大 (active process)”。
amplifier:n.[电子]放大器,扩大器;扩音器; process:v.处理;加工;列队行进;n.过程,进行;方法,adj.经过特殊加工(或处理)的;
The active process enhances our hearing and makes possible all the remarkable features that I've already mentioned. 有源放大能增强我们的听力, 并让我刚刚提到过的 所有卓越性能得以实现。
enhances:提高(enhance的第三人称单数); remarkable:adj.卓越的;非凡的;值得注意的;
Let me tell you how it works. 让我讲讲它的工作原理。
First of all , the active process amplifies sound, so you can hear, at threshold , sounds that move the hair bundle by a distance of only about three-tenths of a nanometer . 首先,有源放大过程能放大声音, 因此你能听见的最小声音 可以低到让毛束移动仅 0.3 纳米。
First of all:adv.首先; amplifies:vt.放大,扩大;增强;详述;vi.详述; threshold:n.入口;门槛;开始;极限;临界值; nanometer:n.[计量]毫微米(即十亿分之一米);
That's the diameter of one water molecule . 这相当于一个水分子的直径。
diameter:n.直径;对径;放大率;放大倍数; molecule:n.[化学]分子;微小颗粒,微粒;
It's really astonishing . 非常惊人。
astonishing:adj.令人十分惊讶的;v.使十分惊讶;使吃惊;(astonish的现在分词)
The system can also operate over an enormously wide dynamic range. 这个系统也可以 在极其宽广的动态范围下运行。
enormously:adv.巨大地,庞大地;非常地,在极大程度上; dynamic:n.动力; adj.充满活力的;
Why do we need this amplification ? 我们为什么需要这种扩音？
amplification:n.[电子]放大(率);扩大;详述;
The amplification, in ancient times, was useful because it was valuable for us to hear the tiger before the tiger could hear us. 在古时候,这种放大很有用, 因为赶在老虎听见我们之前, 听见老虎的声音是性命攸关的。
valuable:adj.有价值的;贵重的;可估价的;n.贵重物品;
And these days, it's essential as a distant early warning system. 而在现代,它则是重要的 远距离早期预警系统。
essential:n.要点;要素;实质;必需品;adj.完全必要的;必不可少的;极其重要的;本质的; distant:adj.遥远的;远处的;久远的; early warning:adj.预先警报的,预警的;远程警戒的;
It's valuable to be able to hear fire alarms or contemporary dangerous such as speeding fire engines or police cars or the like. 它有利于我们听见火警声, 或者当代的危险信号, 如疾驰的救火车或警车之类。
contemporary:n.同时代的人;同时期的东西;adj.当代的;同时代的;属于同一时期的;
When the amplification fails, our hearing's sensitivity plummets , and an individual may then need an electronic hearing aid to supplant the damaged biological one. 当扩音系统损坏时, 我们的听觉灵敏度会骤降, 个体可能需要借助电子助听器 以弥补损坏的生物听觉系统。
sensitivity:n.敏感;敏感性;过敏; plummets:v.大幅下跌;垂直落下(plummet的三单形式);n.[测]铅锤(plummet的复数); individual:n.个人;有个性的人;adj.单独的;个别的; electronic:adj.电子的;电子器件的;电子设备的; hearing aid:n.助听器; supplant:vt.代替;排挤掉; biological:adj.生物学的;生物的;与生命过程有关的;加酶的;n.[药]生物制品;
This active process also enhances our frequency selectivity . 有源放大过程也能增强 我们对频率的辨识。
frequency:n.频率;发生率;重复率;频繁; selectivity:n.选择性;分离性;选择度;
Even an untrained individual can distinguish two tones that differ by only two-tenths of a percent, which is one-thirtieth of the difference between two piano notes, and a trained musician can do even better. 即使是未经训练的常人也可以区分 相差仅 0.2% 的两个音调, 也就是相邻钢琴音调 差距的 30 分之一, 一位训练有素的音乐家 还能辨认得更准。
untrained:adj.未经训练的; distinguish:vt.区分;辨别;使杰出,使表现突出;vi.区别,区分;辨别; tones:n.声调;基本音色(tone的复数);v.调节音调(tone的第三人称单数);
This fine discrimination is useful in our ability to distinguish different voices and to understand the nuances of speech. 这样精细的辨识能力 有利于我们分辨不同人的声音, 以及理解话语中细微的差别。
discrimination:n.歧视;区别,辨别;识别力; nuances:细微差别;
And, again, if the active process deteriorates , it becomes harder to carry out verbal communication. 同样的,如果有源放大的效果下降, 言语交流将变得更加困难。
deteriorates:vi.恶化,变坏;vt.恶化; verbal:adj.口头的;言语的;动词的;照字面的;n.动词的非谓语形式;
Finally , the active process is valuable in setting the very broad range of sound intensities that our ears can tolerate , from the very faintest sound that you can hear, such as a dropped pen, to the loudest sound that you can stand -- say, a jackhammer or a jet plane. 最后,有源放大过程有利于扩大 耳朵能忍受的声音强度范围, 从能听见的最弱声响, 比如,笔掉在地上的声音, 到能忍受的最大声响, 比如,地钻或者喷气式飞机。
Finally:adv.终于;最终;(用于列举)最后;彻底地; intensities:强烈; tolerate:v.容忍;忍受;容许;包容; faintest:adj.一点也不的(用于否定句,加强语气);极小的; jackhammer:n.手提钻;
The amplitude of sounds spans a range of one millionfold , which is more than is encompassed by any other sense or by any man-made device of which I'm aware. 声音强度的范围 可达 100 万倍之广, 这个幅度超过了任何其他感官, 或是我所知的任何人造设备。
amplitude:n.振幅;丰富,充足;广阔; spans:n.[建]跨度;一段时间(span的复数);v.跨越;持续;贯穿(span的第三人称单数); millionfold:adj.百万倍的;adv.百万倍地; encompassed:vt.包含;包围,环绕;完成; man-made:adj.人造的;人工的;合成的; device:n.装置;策略;图案;
And again, if this system deteriorates, an affected individual may have a hard time hearing the very faintest sounds or tolerating the very loudest ones. 同样,如果这个系统受损, 一个受其影响的人可能会很难 听见微弱的声响, 或忍受巨大的声响。
tolerating:v.容许,允许;忍受;容忍;能经受;(tolerate的现在分词)
Now, to understand how the hair cell does its thing, one has to situate it within its environment within the ear. 为了理解毛细胞如何履行职责, 我们得先把它置于 耳内的环境里。
situate:vt.使位于;使处于;adj.位于…的;
We learn in school that the organ of hearing is the coiled , snail-shaped cochlea . 上学时我们曾学过,听觉器官 是卷曲的、蜗牛状的耳蜗。
organ:n.[生物]器官;机构;风琴;管风琴;嗓音; coiled:adj.盘绕的;卷成圈的;v.卷(coil的过去式和过去分词);盘绕; cochlea:n.[解剖]耳蜗;
It's an organ about the size of a chickpea . 这个器官如同一颗鹰嘴豆那么大,
chickpea:n.鹰嘴豆(等于garbanzo);
It's embedded in the bone on either side of the skull . 镶嵌在头骨两侧的骨头里。
embedded:adj.嵌入式的;植入的;内含的;v.嵌入(embed的过去式和过去分词形式); skull:n.头盖骨,脑壳;
We also learn that an optical prism can separate white light into its constituent frequencies, which we see as distinct colors. 我们还学过,一个光学棱镜 能把白光分解成不同的组成频率, 在我们眼里就是不同的颜色。
optical:adj.光学的;眼睛的,视觉的; prism:n.棱镜;[晶体][数]棱柱; white light:n.白光; constituent:n.构成要素;选民;成分;adj.组成的;构成的; distinct:adj.明显的;独特的;清楚的;有区别的;
In an analogous way, the cochlea acts as sort of an acoustic prism that splits apart complex sounds into their component frequencies. 与之类似, 耳蜗就像是一个声学棱镜, 能把复杂的声音分解成 不同的组成频率。
analogous:adj.类似的;[昆]同功的;可比拟的; complex:adj.复杂的;合成的;n.复合体;综合设施;
So when a piano is sounded, different notes blend together into a chord . 所以,在弹奏钢琴时, 不同的音符会混合成一个和弦。
blend:v.混合;融合;加入;相称;n.混合;混合物;混合种;混合色; chord:n.弦;和弦;
The cochlea undoes that process. 耳蜗将这个过程逆转,
It separates them and represents each at a different position. 把声音分解,并将每一个 组成部分在不同位置表达出来。
In this picture, you can see where three notes -- middle C and the two extreme notes on a piano -- are represented in the cochlea. 在这张图里,你可以看见三个音符—— 中央 C 和钢琴两端的音符—— 在耳蜗内部被呈现的位置。
middle C:n.中央C音; extreme:adj.极端的;极度的;偏激的;尽头的;n.极端;末端;最大程度;极端的事物;
The lowest frequencies go all the way up to the top of the cochlea. 最低的频率会到达耳蜗的顶部。
The highest frequencies, down to 20,000 Hz, go all the way to the bottom of the cochlea, and every other frequency is represented somewhere in between. 高达 2 万赫兹的最高频率 则会到达耳蜗的底部, 所有其他频率都在中间 的某个地方表示出来。
And, as this diagram shows, successive musical tones are represented a few tens of hair cells apart along the cochlear surface. 另外,如图所示, 连续的音调在耳蜗表面的表达位置 相隔几十个毛细胞。
successive:adj.连续的;继承的;依次的;接替的; cochlear:adj.耳蜗的;
Now, this separation of frequencies is really key in our ability to identify different sounds, because very musical instrument , every voice, emits a distinct constellation of tones. 而今,这种频率的分离 对我们区分不同声音至关重要, 因为每件乐器, 每个人声, 都能发出一组与众不同的特定音调。
separation:n.分离;分开;分割;隔离; identify:v.识别:鉴定:确认:发现: musical instrument:n.乐器; emits:发出;放射;发行(emit的动词单数第三人称形式); constellation:n.[天]星座;星群;荟萃;兴奋丛;
The cochlea separates those frequencies, and the 16,000 hair cells then report to the brain how much of each frequency is present. 耳蜗将这些频率进行分离, 1 万 6 千个毛细胞 随之将每个频率的数量 汇报给大脑。
The brain can then compare all the nerve signals and decide what particular tone is being heard. 大脑接下来便将 所有的神经信号进行比对, 判断出听到了哪个特定音调。
compare:v.比较;对比;n.比较;
But this doesn't explain everything that I want to explain. 但这还没有涵盖我想解释的一切。
Where's the magic? 其魔力在何处？
I told you already about the great things that the hair cell can do. 我已经为各位介绍了 毛细胞有多厉害。
How does it carry out the active process and do all the remarkable features that I mentioned at the outset ? 那么它是如何进行有源放大, 并完成我开始时 提到的所有非凡特性的？
outset:n.开始;开端;
The answer is instability . 答案是:不稳定性。
instability:n.不稳定(性);基础薄弱;不安定;
We used to think that the hair bundle was a passive object, it just sat there, except when it was stimulated . 我们曾经认为, 毛束是一个被动物体, 没有外界刺激的时候, 它是静止不动的。
passive:adj.被动的,消极的;被动语态的;n.被动语态; stimulated:adj.受激的;v.刺激(stimulate的过去式和过去分词);
But in fact, it's an active machine. 但事实上,它是一个主动的机器。
It's constantly using internal energy to do mechanical work and enhance our hearing. 它一直在使用内部能量 进行机械工作, 并增强我们的听力。
constantly:adv.不断地;时常地; internal:n.内脏;本质;adj.内部的;里面的;体内的;(机构)内部的; mechanical:adj.机械的;力学的;呆板的;无意识的;手工操作的;
So even at rest, in the absence of any input , an active hair bundle is constantly trembling . 即使在静息状态, 没有任何输入信号的情况下, 一根活跃的毛束 也一直不停地在颤动,
in the absence of:缺乏,不存在;无…时,缺少…时; input:n.投入; v.把(数据等)输入计算机; trembling:v.颤抖;极担心;焦虑;恐惧;(tremble的现在分词)
It's constantly twitching back and forth . 不停地前后抖动。
twitching:n.颤搐;v.使抽搐;猛拉;夺走(twitch的ing形式); back and forth:前后移动的,来回的,反复的;
But when even a weak sound is applied to it, it latches on to that sound and begins to move very neatly in a one-to-one way with it, and by so doing, it amplifies the signal about a thousand times. 但当哪怕是很微弱的声响接触到它时, 它便立刻揪住那个声响, 并开始步调一致地 和那个声音进行一对一的运动, 与此同时,也将信号 放大了约一千倍。
applied:adj.应用的;实用的;v.应用;使用;申请,请求;(apply的过去分词和过去式) latches:n.[计]门闩线路; v.用插销插上; neatly:adv.整洁地;熟练地;灵巧地; one-to-one:adj.一对一的;一一对应的;
This same instability also enhances our frequency selectivity, for a given hair cell tends to oscillate best at the frequency at which it normally trembles when it's not being stimulated. 同样的不稳定性也能增强 我们对频率的辨识度, 因为某个毛细胞摆动的最佳频率, 一般是它在不受刺激时 自然抖动的频率。
oscillate:vt.使振荡;使振动;使动摇;vi.振荡;摆动;犹豫; normally:adv.正常地;通常地,一般地; trembles:n.颤抖(tremble的复数); v.颤抖;
So, this apparatus not only gives us our remarkably acute hearing, but also gives us the very sharp tuning . 所以,这个“机器”不仅 让我们有了非常敏锐的听觉, 还让我们能敏锐地分辨音调。
remarkably:adv.非常;极为;格外;出乎意料地 acute:adj.严重的,[医]急性的;敏锐的;激烈的;尖声的; sharp:锋利的,尖的 tuning:n.调谐;收听;调音;v.(为乐器)调音;调节(发动机);调频道;(tune的现在分词)
I want to offer you a short demonstration of something related to this. 关于这一点, 我想为各位进行一段简短的演示。
demonstration:n.示范;演示;论证;证明;
I'll ask the people who are running the sound system to turn up its sensitivity at one specific frequency. 我会请负责音响系统的工作人员 调高系统针对某个 特定频率的敏感度。
specific:adj.特殊的,特定的;明确的;详细的;[药]具有特效的;n.特性;细节;特效药;
So just as a hair cell is tuned to one frequency, the amplifier will now enhance a particular frequency in my voice. 就像毛细胞被调至某个特定频率, 现在扩音器会增强 我声音中的某个特定频率。
tuned:v.(为乐器)调音,校音;调整,调节(发动机);调频道(tune的过去分词和过去式)
Notice how specific tones emerge more clearly from the background. 留意一下,特定的声调是如何 更清晰地从背景音里浮现出来。
emerge:v.浮现;显现;暴露;露出真相;
This is exactly what hair cells do. 毛细胞的作用正是这样。
Each hair cell amplifies and reports one specific frequency and ignores all the others. 每个毛细胞会放大 并汇报某个特定频率, 而忽略所有其他频率。
ignores:v.忽视;对…不予理会;不予理睬;(ignore的第三人称单数)
And the whole set of hair cells, as a group, can then report to the brain exactly what frequencies are present in a given sound, and the brain can determine what melody is being heard or what speech is being intended . 整套毛细胞,作为一个组合, 随后便能向大脑汇报 一个声音中具体包含了哪些频率, 大脑就能依此判断 我们听到了什么旋律, 或是声音是在说什么。
determine:v.决定;确定;测定;查明;形成;影响;裁决;安排; melody:n.旋律;歌曲;美妙的音乐; intended:adj.预定的;计划的;v.打算;计划;想要;(intend的过去分词和过去式)
Now, an amplifier such as the public address system can also cause problems. 像广播系统这样的扩音器 也可能造成问题。
public address system:n.广播系统;
If the amplification is turned up too far, it goes unstable and begins to howl or emit sounds. 如果增幅过度, 它会变得不稳定,开始嚎叫, 或是发出杂音。
unstable:adj.不稳定的;变化莫测的;(行为、情绪)反复无常的
And one wonders why the active process doesn't do the same thing. 你或许会纳闷,为什么 有源放大不会发生同样的问题。
Why don't our ears beam out sounds? 我们的耳朵为什么不会发射声音？
beam:n.光线; v.发射(电波);
And the answer is that they do. 而回答是:它们是会出声的。
In a suitably quiet environment, 70 percent of normal people will have one or more sounds coming out of their ears. 在一个足够安静的环境里, 70% 的正常人 耳朵里会发出一种或多种声音。
suitably:adv.适当地;相配地;适宜地;
(Laughter) （笑声）
I'll give you an example of this. 让我给各位举个例子。
You will hear two emissions at high frequencies coming from a normal human ear. 你会听到来自正常人耳的 两个高频率声响。
emissions:n.(光、热、气等的)发出,排放;排放物;散发物;(emission的复数)
You may also be able to discern background noise, like the microphone 's hiss , the gurgling of a stomach, the heartbeat , the rustling of clothes. 你或许还能辨别出背景噪音, 像是麦克风的嘶嘶声、 肚子的咕咕声、心跳声、 衣服的摩擦声。
discern:v.识别;觉察出;了解; microphone:n.麦克风;传声器;话筒; hiss:vi.发出嘘声;发嘘声;n.嘘声;嘶嘶声; gurgling:n.气过水声;v.作汩汩声(gurgle的现在分词); heartbeat:n.心跳;情感; rustling:n.沙沙声; v.沙沙作响; (rustle的现在分词)
(Hums, microphone hiss, dampened taps, clothes rustling) （嗡嗡声、麦克风杂音、 水龙头的水声、衣物沙沙声）
dampened:使潮湿;抑制(dampen的过去式和过去分词);
This is typical . 这是比较典型的。
typical:adj.典型的;特有的;象征性的;
Most ears emit just a handful of tones, but some can emit as many as 30. 大多数耳朵只会发出少数几种声调, 但有的能发出 30 种之多。
Every ear is unique , so my right ear is different from my left, my ear is different from your ear, but unless an ear is damaged, it continues to emit the same spectrum of frequencies over a period of years or even decades. 每只耳朵都是独特的, 所以我的右耳和我的左耳不同, 我的耳朵和你的耳朵不同, 但除非耳朵受到损害, 它会在若干年,甚至数十年内, 持续发出特定谱系的频率。
unique:adj.独特的,稀罕的;[数]唯一的;n.独一无二的人或物; spectrum:n.光谱;频谱;范围;余象;
So what's going on? 这是怎么回事？
It turns out that the ear can control its own sensitivity, its own amplification. 事实上,耳朵能够控制 它自身的灵敏度, 和自身的扩音幅度。
So if you're in a very loud environment, like a sporting event or a musical concert, you don't need any amplification, and the system is turned down all the way. 如果你在一个很吵的环境里, 比如,体育赛事 或者音乐会现场, 你不需要对声音进行任何放大, 于是系统的扩音幅度就被调到最小。
If you are in a room like this auditorium , you might have a little bit of amplification, but of course the public address system does most of the work for you. 如果你在像这个演讲厅 一样的房间里, 你或许需要对声音进行少许放大, 不过当然了,广播系统 已经帮你完成了大部分工作。
auditorium:n.礼堂,会堂;观众席;
And finally, if you go into a really quiet room where you can hear a pin drop , the system is turned up almost all the way. 最后,如果你进入 一个非常安静的房间, 安静得落针可闻, 那么系统的扩音幅度就会 被调到几乎是最大值。
hear a pin drop:静得连针掉在地上也听得见;
But if you go into an ultraquiet room such as a sound chamber , the system turns itself up to 11, it goes unstable and it begins to emit sound. 但如果你走进一个 超级安静的房间,比如说消音室, 系统会自动调到最大值, 因而它会变得不稳定, 于是开始发出声音。
chamber:n.(身体或器官内的)室,膛; adj.室内的; vt.把…关在室内;
And these emissions constitute a really strong demonstration of just how active the hair cell can be. 这些被释放的声音非常有力地展示了 毛细胞有多活跃。
So in the last minute, I want to turn to another question that might come up, which is: Where do we go from here? 那么在最后一分钟里,我想 谈谈一个各位可能会问的问题: 我们的研究之后将如何发展？
And I would say that there are three issues that I would really like to address in the future. 我认为在未来, 我很想研究的课题有三个。
issues:n.重要议题;争论的问题;v.宣布;公布;发出;(issue的第三人称单数和复数)
The first is: What is the molecular motor that's responsible for the hair cell's amplification? 其一:负责毛细胞 扩音作用的分子马达是什么？
Somehow , nature has stumbled across a system that can oscillate or amplify at 20,000 cycles per second, or even more. 大自然似乎设法误打误撞地发现了 一个能以 2 万赫兹,甚至更高的频率 振动或扩音的系统。
Somehow:adv.以某种方法;莫名其妙地; stumbled:v.绊脚;跌跌撞撞地走;蹒跚而行;(stumble的过去分词和过去式) amplify:vt.放大,扩大;增强;详述;vi.详述;
That's much faster than any other biological oscillation , and we would like to understand where it comes from. 这比任何别的生物振动都快, 我们也想弄明白它是怎么来的。
oscillation:n.振荡;振动;摆动;
The second issue is how the hair cell's amplification is adjusted to deal with the acoustic circumstances . 第二个课题是,毛细胞的扩音作用
adjusted:adj.调整过的,调节了的;v.调整;校正(adjust的过去分词); circumstances:n.情况;环境;情形;(circumstance的复数)
Who turns the knob to increase or decrease the amplification in a quiet or in a loud environment? 是谁转动旋钮, 在安静环境中增强扩音, 在吵闹环境中降低扩音的？
knob:n.把手;瘤;球形突出物;vi.鼓起;vt.使有球形突出物; decrease:v.降低;减少;缩小;减弱;n.减少;减小量;所减少的总量;减缩位置;
And the third issue is one that concerns all of us, which is what we can do about the deterioration of our hearing. 第三个课题和我们每个人息息相关, 也就是针对听力衰退 我们能做些什么。
concerns:n.关注; v.使关心(concern的三单形式); deterioration:n.恶化;退化;堕落;
Thirty million Americans, and more than 400 million people worldwide , have significant problems on a daily basis with understanding speech in a noisy environment or over the telephone. 三千万美国人, 还有全世界范围内超过 4 亿人, 每天在嘈杂环境中、 或在电话里试图理解对话时, 都会明显感到困难。
worldwide:adj.全世界的;adv.在世界各地; significant:adj.重大的;有效的;有意义的;值得注意的;意味深长的;n.象征;有意义的事物;
Many have even worse deficits . 有些人的听力缺陷更加严重,
deficits:n.[财政]赤字,亏损(deficit的复数形式);
Moreover , these deficits tend to get worse with time, because when human hair cells die, they're not replaced by cell division . 甚至还会随着时间而进一步恶化, 因为当人体的毛细胞凋亡后, 它们不会通过细胞分裂得到补充。
Moreover:adv.而且;此外; division:n.师;分配;分开;分歧;
But we know that nonmammalian animals can replace their cells, and those creatures' cells are dying and being replaced throughout life, so the animals maintain normal hearing. 但我们知道,非哺乳动物 能够更换它们的（毛）细胞, 这些生物的（毛）细胞在一生中 不停地死亡、更换, 使得这些动物能维持正常听力。
throughout:adv.自始至终,到处;全部;prep.贯穿,遍及; maintain:v.维持;保持;维修;保养;坚持(意见);
Here's an example from a little zebra fish. 这是来自一条小斑马鱼的例子。
The cell at the top will undergo a division to produce two new hair cells. 顶端的细胞会进行分裂, 产生两个新的毛细胞。
undergo:vt.经历,经受;忍受;
They dance for a little bit, and then settle down and go to work. 它们会手舞足蹈一会儿, 然后便安顿下来,专心工作。
settle:v.定居;结算;停留;确定;n.高背长椅(老式木家具,有扶手,座下多带柜);
So we believe that if we can decode the molecular signals that are used by these other animals to regenerate their hair cells, we'll be able to do the same thing for humans. 因此,我们相信, 如果我们能够解码 其他这些动物用来 再生毛细胞的分子信号, 我们就能为人类做同样的事情。
decode:vt.[计][通信]译码,解码;vi.从事破译工作; regenerate:vt.使再生;革新;vi.再生;革新;adj.再生的;革新的;
And our group and many other groups are now engaged in research trying to resurrect these amazing hair cells. 目前,我们的团队和 许多其他团队都致力于研究 如何让这些美妙的毛细胞复活。
engaged in:从事于;忙于; resurrect:v.使复兴;起死回生;重新应用;使复活;
Thank you for your attention. 谢谢各位的聆听。
(Applause) （掌声）