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标题: 8.29裤头，一战720分手放狗 [打印本页]
作者: Sandyqzz 时间: 2019-8-29 18:08
标题: 8.29裤头，一战720分手放狗
虽然一道寂静都没遇到，还是感恩CD论坛。
V： 一篇reading是关于parasite跟host的
AWA：一个汽车公司CEO给股东的信：计划收购一家另一个国家破产的汽车公司，因为那个国家人口增长很快；公司打算关掉破产公司的生产线，用自己公司的明星产品来代替；保留大部分原员工，同时派自己优秀员工，这样保证顺利对接。
1. PS，成本减去一个数，销售价格不变，利润从销售价格的20%增加到30%，问如果原来的成本是120的话，减去之后的价格？
构筑答案：105
2. PS, 9^2X+9^-2X=62，求3^2X+3^-2X
构筑答案：8
3. PS, 1 gallon液体可以覆盖450 feet，问覆盖600 yards需要几gallon? 1yard=3feet. 答案不记得了
4. DS，5个正整数，平均数是24，问有几个数大于25？
条件1: Largest 2的和=49
条件2: Least 2的和=38
5. 下图，一个长方形，长=30，两边是等边三角形，边长=4，求两个三角形顶点之间的距离最接近哪个数？
构筑答案：42
作者: Sandyqzz 时间: 2019-8-29 18:10
第5题的图
[attach]239804[/attach]
作者: AnthonySun1996 时间: 2019-8-29 18:21
谢谢构筑
第四题怎么选啊
作者: Sandyqzz 时间: 2019-8-29 18:29
我选的A
作者: annvan123 时间: 2019-8-29 19:03
第四个题感觉是不是题目不太对 想问问我的想法对不对，以及求一下构筑的思路TTT
设五个数从小到大是a1 a2 a3 a4 a5 (不知道题里有没有说是不一样的五个数，先按都不一样来做：
（1）：a4+a5=49 ， 则a1+a2+a3=71. 此时a4最大等于24，那么a3最大等于23，但是此时a1+a2=48了，总得有一个大于a3...和题目就矛盾了貌似
（2）：a1+a2=38, 则a3+a4+a5=82 , 此时a2 最小是20，后三个数可以有1个或者2个或者3个大于25。所以不阔以。
不知道有没有什么简单的思路哇 明天考试好慌
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还有如果这五个数允许重复的话，是不是（1）推出来的数列就只能是：23,24,24,24,25了呢？
作者: Sandyqzz 时间: 2019-8-29 19:08
条件二的数字不是100%确定哈 但是是30几的数 选A应该是对的
作者: annvan123 时间: 2019-8-29 19:10
好的谢谢！构筑当时是怎么考虑的呢？有木有什么其他简便一点儿的思路哇？
作者: billyisfragile! 时间: 2019-8-29 19:28
https://link.springer.com/article/10.1007%2Fs00442-005-0345-4
是原文吗？
Abstract
Host age is one of the key factors in host–parasite relationships as it possibly affects infestation levels, parasite-induced mortality of a host, and parasite distribution among host individuals. We tested two alternative hypotheses about infestation pattern and survival under parasitism in relation to host age. The first hypothesis assumes that parasites are recruited faster than they die and, thus, suggests that adult hosts will show higher infestation levels than juveniles because the former have more time to accumulate parasites. The second hypothesis assumes that parasites die faster than they are recruited and, thus, suggests that adults will show lower infestation levels because of acquired immune response and/or the mortality of heavily infested juveniles and, thus, selection for less infested adults. As the negative effects of parasites on host are often intensity-dependent, we expected that the age-related differences in infestation may be translated to lower or higher survival under parasitism of adults, in the cases of the first and the second hypotheses, respectively. We manipulated ectoparasite numbers using insecticide and assessed the infestation pattern in adult and juvenile gerbils (Gerbillus andersoni) in the Negev Desert. We found only a partial support for age-dependent parasitism. No age-related differences in infestation and distribution among host individuals were found after adjusting the ectoparasite numbers to the host’s surface area. However, age-related differences in survival under parasitism were revealed. The survival probability of parasitized juveniles decreased in about 48% compared to unparasitized hosts while the survival probability of adults was not affected by ectoparasites. Our results suggest that the effect of host age on host–parasite dynamics may not explicitly be determined by age-dependent differences in ectoparasite recruitment or mortality processes but may also be affected by other host-related and parasite-related traits.
Alternatively, it is possible that theprocesses of ectoparasite recruitment and ectoparasite mortality depend on hostage but operate in opposite directions and, thus, the two processes cancel eachother (Anderson and Gordon 1982). For example, the tendency of adult wood mice (Apodemussylvaticus) to accumulate more nematodes Heligmosomoides polygyrusthan juvenile wood mice counter the better ability of adults to mount an immuneresponse (Quinnell 1992). Furthermore, the processes of ectoparasiterecruitment and ectoparasite mortality may be influenced by factors other thanthe level of host exposure, immune response, and parasite-induced hostmortality. For instance, in a larger-scale survey, it was shown that age-biasedflea parasitism might change from juvenile-biased toward adult-biased as afunction of soil temperature and ED (Hawlena et al. 2005).
作者: Sandyqzz 时间: 2019-8-29 19:46
是原文！
作者: Sandyqzz 时间: 2019-8-29 19:47
群里讨论的截图发给你看哈
[attach]239811[/attach]
作者: annvan123 时间: 2019-8-29 20:00
ok 谢谢辽~~~
作者: krystal89 时间: 2019-8-29 21:22
数学第四题的题目应该是有几个数大于等于25才能选a吧？
作者: 850802349 时间: 2019-8-29 21:35
老哥你实在是太厉害了。。。
作者: gavincheung 时间: 2019-8-29 21:37
好像是这样的，这个好细节。。
作者: EvenX 时间: 2019-8-29 22:48
谢谢楼主狗狗，楼主求问第三题是覆盖的面积还是单纯地按长度换算呀
作者: EvenX 时间: 2019-8-29 22:59
同意！
作者: Sandyqzz 时间: 2019-8-30 08:09
覆盖的面积
作者: amanda823 时间: 2019-8-30 16:53
谢谢构筑
作者: 妮卡卡 时间: 2019-8-31 22:06
楼主，三角形顶点之间距离不是30+4根号3吗，约等于37？为什么会是42呀……
作者: 蛋卷酱 时间: 2019-9-1 09:50
太牛了老哥
作者: Starfish2 时间: 2019-9-1 09:56
哈哈哈哈RON的头像~
作者: frankie_Master 时间: 2019-9-2 22:19
第二题是怎么算的啊？
作者: Liqueur-xy 时间: 2019-9-3 11:32
我也觉得。。
作者: MacBurns4ever 时间: 2019-9-4 17:19
同意！
作者: lucifer7 时间: 2019-9-7 13:54
妮卡卡 发表于 2019-8-31 22:06
楼主，三角形顶点之间距离不是30+4根号3吗，约等于37？为什么会是42呀…… ...
同意！
作者: lucifer7 时间: 2019-9-9 09:31
妮卡卡 发表于 2019-8-31 22:06
楼主，三角形顶点之间距离不是30+4根号3吗，约等于37？为什么会是42呀…… ...
我算出来也是30+4*跟号3，同问
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