[阅读]六月二十七日至七月二十八日阅读寂静汇总（结贴）

ozymendias

http://forum.chasedream.com/GMAT_Preparation/thread-377326-33-1.html?userid=407253
第二十一篇：树的年轮

第一段：年轮的疏密可以看出树木生长期间的天气变化，热带雨林的树木因为一年内天气变化很小，年轮不明显，有2个解决方法1 氧和碳同位素的分析，但是碳分析耗时太长，2 还有一种什么方法和sediment的方法，不过这两种方法有问题，不行。

第二段：P科学家提出一种新的方法，优点：节省事件，而且和同位素测试出来的方法相同。（说明准确度高）

第三段：但是这个方法还有一些问题：1是否所有的热带树木都可以这也分析还是仅有几种特殊的树木可以。2 忘了，最后一句是P科学家collaborate了很多其他方面的专家，继续进行研究。

-- by 会员 gleila (2010/6/30 16:54:59)

谢谢gleila！！！非常感谢！！

venus2elva

多谢多谢。

gmm03

楼主的贡献很多，非常感谢。

llw_66

Thanks !!! 辛苦了!!!

nowwsy

辛苦你拉~~
http://forum.chasedream.com/GMAT_Math/thread-467299-1-1.html
第二篇
考古
RC-33 ANT （KEY WORD: ant, nomadic pattern
【版本1】一篇是讲ant 的nomadic pattern和什么pattern的，没看懂。
【版本2】03/11 VERBAL碰上两道机经阅读，一个蚂蚁那个。
第一段说蚂蚁分两种习性，不冬眠的时候怎样怎样，冬眠的时候怎样怎样。
第二段解释说蚂蚁这种习性可能是跟它生在什么时候有关系，蚁后生很多小蚂蚁幼虫，有的在不冬眠的时候发展成大蚂蚁，就变成了类似工兵蚂蚁，可能是，有的在冬眠的时候发育，就变成什么什么蚂蚁。文章不长，但是生词很多，看着晕。题目有一道推断题，问第二段说如果工兵蚂蚁不在不冬眠的时候发育会变成什么样。
【版本3 V38, 74】03/17 ant 那一道：3道题目
虽然只有两段，但还是觉得有点小tricky,也可能是我最后做这一篇时间很紧吧. ant, stetey(?) phrase 和 nomatic phrase
1.问primary purpose JJ作者的答案：注意，第一段有提到一个earlier observation, 作者对这个是做了补充，而非反驳或什么的. 所以选项选有supplement 的那一项
2.文章最后一句话高光，问目的。JJ作者：是讲ant 完成nomatic phrase后会到达steery, 选项里有一项是evidence to support the conclusion that nomatic period is linked to reproductive cycle. JJ中没有提到的关键词：nomatic period is linked with reproductive cycle.这是作者在第一段末尾说的
3.是nomatic phase 和stetery 期间ant 行为的比较，主要在第二段定位。我做时有点晕。有pupae,好像是这词，我也不知道是什么意思

有益补充：google 出来的 有点像  里面还有说SP和NP两个阶段   大家可以搜一下
Nomadic behavior of the army ant Neivamyrmex nigrescens was studied in a desert-grassland habitat. Six colonies were followed through eight nomadic phases (94 nomadic days) while direction and distance of emigrations, growth of larvae, number of adults and larvae per colony were determined.

In all colonies, the nomadic phase began when newly enclosed adults and small larvae were present, and ended when the larvae were fully grown. Average emigration distance was positively related to number of larvae in the colony. These findings support Schneirla's theory that brood stimulation is a proximate cause of the nomadic phase.
Failures to emigrate were equally likely at all points in the nomadic phase, and there was no systematic increase in emigration distance as the phase progressed. These findings do not support Schneirla's version of brood-stimulative theory.

Number of adults per colony was positively related to the directionality of the nomadic phase; however, both the direction and distance of emigrations varied unpredictably from one nomadic day to the next, in marked contrast to predictions from optimal foraging theory.

Schneirla's theory is useful in predicting phase differences in colony behavior, but it does not account for characteristics such as frequency, direction, or distance of emigrations within the nomadic phase. These aspects of nomadic behavior are more closely related to characteristics of the habitat such as prey density and availability of nest sites. Army ant nomadism in this habitat may depart from the optimum because of high prey density, small colony size, or lack of nesting sites.

有益补充2：蚂蚁那篇，有解释 statary phase, 凑合着用！（感谢黄GG）
Eciton army ants have a bi-phasic lifestyle where they alternate between a nomadic phase and a stationary stage. In the stationary or statary phase ('statary' is an old English word meaning "to stand in place"), which lasts about three weeks, the ants remain in the same location every night. They make a nest out of their own bodies, protecting the queen and her eggs in the middle. This temporary home is known as a bivouac. In the nomadic phase the ants move their entire colony to a new location nearly every night for two weeks.
When the ants first enter the statary phase, the queen's body swells massively and she lays as many as 250,000 eggs in less than a week. While the eggs mature, the ants swarm with less frequency and intensity. When the eggs hatch, the excitement caused by the increased activity of the larvae causes the colony to enter the nomadic phase. The colony swarms much more intensely and nearly every day, and the ants move to a new location every night. After two weeks, around the time when the larvae begin to pupate, the colony again enters the statary phase, and the cycle begins anew (Schneirla, 1971).

nowwsy

继续麻烦你袅~~
第三篇 刚才那个网址
34。14世纪的有关英国封建领主的东西
新老观点型：关于封建领主影响英国经济长期发展的真正原因
1）传统观点。14世纪时人民的生活水平日益下降，甚至到了威胁生存的地步（开头句）。接着说了英国lord和tenant的关系，tenant的生活如何疾苦，如何受lord剥削控制，以至于他们的关系像是master和serf（农奴）。学者们还认为这些地主好吃懒做，表现在很重视眼前的享受和消费，而不在乎长远的发展，所以经济一直处于投资不足的状态（underinvestment），还说了一些其他因素，这些都妨碍了宏观经济的发展。
2）新证据。虽然老观点有着很大的吸引力（作者用了compelling），但是它越来越不能回答近期发现的一些新证据（主题句）。老观点忽视了（overlook）另一个不同于lord和tenant的新人群：free tenant。他们不是serf，不受地主的人身控制，只用按一个较低的fixed  rate缴纳租金。最后提到其实tenant也不是原来想的那样软弱无力，他们已经能够组织起来和地主negotiate rate。
3）进一步的补充。为了应付tenant想多租地扩大自身利益的欲望，地主想出了一系列方法。。。,生词很多，看不太懂。。。结果就是造成巨大的unemployment in rural area. 地主的这种做法相当于对经济的一个“brake”，阻碍了14世纪的英国经济发展。（有题，说地主的做法对谁有利？选项里都分了从长期看和从短期看，两方面讨论）[推测：短期对领主有利，但不利于长期的经济发展。因为造成乡村的失业]感觉第三段可能是对第一段经济学家的反驳，说这才是阻碍经济发展的真正原因，当然这只是我个人的看法。

nowwsy

http://forum.chasedream.com/GMAT_Math/thread-467299-1-1.html#last
你懂lz~~

Avatar800

楼主号勤快，真是太谢谢你了~~~这么早起来整理狗狗

glorysnowhi

楼主辛苦啦！谢谢啊

azhang2010

can anybody check whether the para below is the one about var during the gmat?? thanks.
it looks quite similiar.
第三篇 Var金融指标



There are many such models, but by far the most widely used is called VaR — Value at Risk. Built around statistical ideas and probability theories that have been around for centuries, VaR was developed and popularized in the early 1990s by a handful of scientists and mathematicians — “quants,” they’re called in the business — who went to work for JPMorgan. VaR’s great appeal, and its great selling point to people who do not happen to be quants, is that it expresses risk as a single number, a dollar figure, no less.

VaR isn’t one model but rather a group of related models that share a mathematical framework. In its most common form, it measures the boundaries of risk in a portfolio over short durations, assuming a “normal” market. For instance, if you have $50 million of weekly VaR, that means that over the course of the next week, there is a 99 percent chance that your portfolio won’t lose more than $50 million. That portfolio could consist of equities, bonds, derivatives or all of the above; one reason VaR became so popular is that it is the only commonly used risk measure that can be applied to just about any asset class. And it takes into account a head-spinning variety of variables, including diversification, leverage and volatility, that make up the kind of market risk that traders and firms face every day.

Another reason VaR is so appealing is that it can measure both individual risks — the amount of risk contained in a single trader’s portfolio, for instance — and firmwide risk, which it does by combining the VaRs of a given firm’s trading desks and coming up with a net number. Top executives usually know their firm’s daily VaR within minutes of the market’s close.

Risk managers use VaR to quantify their firm’s risk positions to their board. In the late 1990s, as the use of derivatives was exploding, the Securities and Exchange Commission ruled that firms had to include a quantitative disclosure of market risks in their financial statements for the convenience of investors, and VaR became the main tool for doing so. Around the same time, an important international rule-making body, the Basel Committee on Banking Supervision, went even further to validate VaR by saying that firms and banks could rely on their own internal VaR calculations to set their capital requirements. So long as their VaR was reasonably low, the amount of money they had to set aside to cover risks that might go bad could also be low.