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sss  2012-4-08   why the old paper is yellow  CN

随着时间流逝，白纸会变成很独特的黄色。但是，为什么呢？为了说明这点，科学家人工模拟现代纸张老化，以便在分子水平上观察其变化。这个研究在“自然现象回顾信”上刊登了。48天里，3个未漂白的纸样品在反应器里迅速老化来模拟不同的环境条件。之后研究者将这3个人工老化的样品和真正的版本相比较--3张在15世纪的欧洲手工制造出来的纸张。这个技术可以让他们去估测老化的类型和老化的程度。老化的纸张大约90%的重量是纤维素--一种用于构成植物细胞壁的坚固材料。随时间流逝，纤维素的纤维氧化了，这个过程将部分分子改变成我所说的生色团，它会吸收光线。白纸之所以白是因为它反射所有的光线。老化的充满生色团的纸张反射光波是纸张看起来是黄色的。这个没有破坏作用的技术可以预示研究可保护甚至漂白古时的书本和艺术作品。并且赋予文件保护一个更加白亮的外表。

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sss 2012-04-08 why the paper is yellow？  ENI  EN2

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sss 2012-04-08  why the old paper is yellow？  总结帖

artificially 人工地

molecular 分子的

unbleached 未漂白的
the real deal
gauge      评估
cellulose 细胞膜质，纤维素
sturdy 坚固的
plant cell walls  植物细胞壁
oxidize 氧化
modify 修改
chromophore发色团
aging 老化的
non-destructive 不具有破坏性的
preserve 防腐处理

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想说一句，这篇sss 挺恶心的，我全误解掉了。

浅吟天

这。。我很弱的。。
lz 每天大概用多少时间弄听力呢？看这帖子哗啦啦的往后翻

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浅吟天真谦虚啊。这个因人而异，不一定的，我目前要大半天。。。你若有什么体会和心得，还望不吝赐教。

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tpo15 lecture 1   中文 I

听一段心理学讲座。几十年以来，心理学家一直在观察我们在有干扰的情况下完成任务的能力。我们是如何防止被干扰的，还有好的集中能力（所需）的条件是什么。早在1982年，研究者想出了一个叫CFQ的东西--认知失败问卷。这个问卷要求人们根据他们在不同的场景下有多经常被分散精力给自己打分，就像，嗯...因为脑子里想着其他的事情而忘了保存电脑文件，或者是忘了看路上的限速标志。乔治？我曾经失去了我的那部分电脑文件，但不是被。。分散精力，我只是忘了保存它。这就是CFQ的问题的部分所在。它没有充分考虑其他的因素，就像健忘。外加上你真的无法说你从一个主观的被人们自己填写的问卷中得到了一个很客观的科学数据。所以出现某个人尝试主观的评价自己分散精力的情况一点也不奇怪。这是由一个叫ML的心理学家设计的一个很简单的电脑游戏。在L的游戏中，人们观看N和X字母在电脑屏幕的特定位置出现和消失。每次他们看见N的时候，按某个键，每次他们看见X，就按另一个键。。。其他的字母也出现在屏幕的周围，并且出现频率逐渐上升，这将分散精力，并且使任务更加困难。L观察到当这些分散精力的东西出现的时候人们的反应时间加长了。这不是很令人惊奇，不是吗？当然不（惊奇）了，是这个实验的另一部分让人惊奇。当难度真的很高，屏幕被布满字母的时候，人们（反而）能更好的看见X和N。你觉得那是为什么呢？嗯，可能是当我们真的在集中精力的时候，我们就很自然的停止感知不相关的信息了，可能我们就是不将它们过脑子了，你理解吗？使得，并且那是假设中的一个，即大脑只是简单地不接收不重要的信息。第二个假设是，我们的确看见了所有的东西，但是大脑将其分类了，不是我们关注的（对象），不论是什么都被看成是次重点。所以L就做了另一个实验，设计（用意在于）去观察在面对逐渐提升的难度时的注意力集中能力缺陷。这次，她用大脑扫描设备来监测大脑特定区域的活动。这个（特定）区域叫做V5，是视觉皮质的一部分。这部分大脑（视觉皮质）处理视觉信号刺激。V5是视觉皮质负责感知移动的部分。又一次，L给人们一个电脑操作任务，他们必须区分上，下  字。。。。或者更难。他们必须计算不同单词中音节的数量。这次，分散精力的东西是背景中移动的星星。你知道，就像你在太空中移动，穿过星群。通常，当那些移动地星星被感知到的时候，V5会被激活。非常肯定的是，L 发现在任务（进行）中，V5区域是活跃的。所以人们的确注意到了移动的星星背景。那意味着人们没有把分散精力的对象关在大脑之外。所以这意味着你提到的第一个假设错了？就是那个当我们集中精力的时候我们甚至没有感知到不相关的信息？是的，没错。这是一点，但不是全部。L还发现，当她将任务变得更难的时候，V5变得没那么活跃了。所以这意味着这时人们并没有真正地注意到星星背景了。这真是非常令人惊讶。并且它证明了第二个假设，即我们的确一直都感知到了所有的事情，但是大脑差别对待分散精力的东西，也是错的。L认为大脑去除或忽略视觉信息。。。。她认为这个能力有限。就像是公路，当有过多的车辆的时候，路就被堵了，谁也过不去。所以当大脑满负荷的时候，没有新的信息可以被接收。现在，这没准是视觉干扰的正确结论，但是更多的研究是需要的来告诉我们大脑是如何处理，例如当饥饿或隔壁有人在唱歌的时候，我们解决数学问题会分心的问题。

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tpo15  lecture 1    EN I



Listen to part of the lecture in a psychology class.For decades,psychologists have been looking at our ability to perform tasks,while other things are going on.How we are able to keep from being distracted,and what the conditions for good concentration are.As long ago as 1982,researchers came up with something called the CFQ,the cognitive failures of questionaire.This questionaire asks people to rate themselves,according to how often they get distracted in different situations.Like um,forgetting to save the computer file because they have something else on their mind.or missing a speed limit sign on the road.John?I've lost my share of the computer files,but not because of I'm being distracted,I just forget to save them.And that's part of the problems with CFQ.It doesn't take other factors into account enough,like forgetfulness.Plus you really can't say you are getting objective scientific results from a subjective questionaire where people report on themselves.So it's no surprise that someone attempted to design an objective way to measure the distraction.It's a simply computer game designed by a psychologist named M L.In L's game, people watch as the N and X appear and disappear in a certain area the computer screen.Everytime they see an N,they press one key,and everytime they see an X,they press another.except other letters also start appearing in the  surrounding area of the screen,with increasing frequency,which create the distraction and make the task more difficult.L observed that people's reaction time slowed as the distraction increased.Oh,that's not too surprising,is it?No,it's not.It's the next part of the experiment that was surprising.When the difficulty really increased,when the screen fills up with letters,People got better at spotting Xes and Ns.Why do you think that happened?Well,maybe when we were really concentrating,we just stop perceive irrelevant information.Maybe we just don't take it in,you know?Yes,and that's one of the hypothesises that was proposed,that the brain simply don't admit the unimportant information.The second hypothesis is that,yes,we do perceive other things,but the brain categorize the information.And whatever's not relevant to what we are concentrating on gets treated as low priority.So L did another experiment,designed to look at the disability to concentrate better in the face of the increased difficulty.This time she used brain scanning equipment to monitor activity in a certain part of the brain.The area is called V5,which is part of the visual cortex,the part our brain set processes to visual stimuli.V5 is the area of the visual cortex that is responsible to the sensation of the movement.Once again,L gives people a computer task to do.They have to distinguish between words in upper and lower case letters,or even harder.They have to count the number of the syllable in different words.This time,the distraction was a moving star field in the background.You know ...looks like you are moving to space passing stars,Normally,area of V5 would be stimulated as those moving stars were perceived,and sure enough,L found that during the task,area of V5 was active.So people were aware of the moving star field.That means people were not locking out the distractions.So doesn't that mean that the first hypothesis you mention is wrong?The one that we don't even perceive the irelevant information when we are concentrating? Yes,that's right,up to a point,but that's not all.L also discovered that as she made the task more difficult,V5 became less active.So that means that now people weren't even noticing the star field at all.That was quite a surprise.and it proved that the second hypothesis,that we do perceive everything all the time but the brain categorizes the distractions differently,well,that wasn't true either.L thinks the solution lie...the brain's ability to ignore the information.She thinks that the capacity is limited.It's like a highway.When there are too many cars,traffic gets stopped,noone can get on.So when the brain is loaded to capacity,no new distraction can be perceived.Now that may be the correct conclusion,for visual distractions.But more researches needed to tell us how the brain deals with say,the distractions of solving a math problem when we are hungry,or when someone is singing in the next room.

浅吟天

牛！加油

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tpo15  lecture1   EN II

Listen to part of a lecture in a psychology class.For decades,psychologists have been looking at our ability to perform tasks,while other things are going on.How we are able to keep from being distracted,and what the conditions for good concentration are.As long ago as 1982,researchers came up with something called the CFQ,the cognitive failures questionnaire.This questionnaire asks people to rate themselves,according to how often they get distracted in different situations.Like umm,forgetting to save a computer file because they had something else on their mind.or missing a speed limit sign on the road.John?I've lost my share of computer files,but not because of I'm easily distracted,I just forget to save them.And that's part of the problem with CFQ.It doesn't take other factors into account enough,like forgetfulness.Plus you really can't say you are getting objective scientific results from a subjective questionnaire where people report on themselves.So it's no surprise that someone attempted to design an objective way to measure distraction.It's a simply computer game designed by a psychologist named M L.In L's game, people watch as the letters N and X appear and disappear in a certain area on the computer screen.Every time they see an N,they press one key,and every time they see an X,they press another.except other letters also start appearing in the  surrounding area of the screen,with increasing frequency,which create the distraction and make the task more difficult.L observed that people's reaction time slowed as these distractions increased.Oh,that's not too surprising,is it?No,it's not.It's the next part of the experiment that was surprising.When the difficulty really increased,when the screen fills up with letters,People got better at spotting Xs and Ns.Why do you think that happened?Well,maybe when we are really concentrating,we just don't perceive irrelevant information.Maybe we just don't take it in,you know?Yes,and that's one of the hypotheses that was proposed,that the brain simply don't admit the unimportant information.The second hypothesis is that,yes,we do perceive other things,but the brain categorizes the information.And what ever' s not relevant to what we are concentrating on gets treated as low priority.So L did another experiment,designed to look at disability to concentrate better in the face of increased difficulty.This time she used brain scanning equipment to monitor activity in a certain part of the brain.The area called V5,which is part of the visual cortex,the part our brain set processes to visual stimuli.V5 is the area of the visual cortex that' s responsible for the sensation of movement.Once again,L gave people a computer task to do.They had to distinguish between words in upper and lower-case letters,or even harder.They had to count the number of the syllables in different words.This time,the distraction was a moving star field in the background.You know where looks like you moving to space passing stars,Normally,area of V5 would be stimulated as those moving stars were perceived,and sure enough,L found that during the task,area of V5 was active.So people were aware of the moving star field.That means people were not blocking out the distractions.So doesn't that mean that the first hypothesis you mention is wrong?The one that says we don't even perceive the irrelevant information when we are concentrating? Yes,that's right,up to a point,but that's not all.L also discovered that as she made the task more difficult,V5 became less active.So that means that now people weren't really noticing the star field at all.That was quite a surprise.and it proved that the second hypothesis,that we do perceive everything all the time but the brain categorizes distractions differently,well,that wasn't true either.L thinks the solution lies in the brain' s ability to accept or ignore visual information.She thinks that this capacity is limited.It's like a highway.When there are too many cars,traffic is stopped,no one can get on.So when the brain is loaded to capacity,no new distraction can be perceived.Now that may be the correct conclusion,for visual distractions.But more research is needed to tell us how the brain deals with say,the distractions of solving a math problem when we are hungry,or when someone is singing in the next room.