不利条件

1Niche construction can lead to stable coexistence of diverse genotypes in spatially structured population, which supports a stable polymorphism even without heterozygote superiority.(2)With habitat deterioration, niche construction accelerates the formation of steady polymorphism and hence impedes the harmful influences of environment on the population, which might embody a life-history strategy of organism under the unfavorable environment.(3)Niche construction results in the coexistence with alternative polymorphism through genotype-environment feedback and limited gene flow.(4)The niche-constructing organism is an active force to alter its environment and hence the direction of natural selection in order to better survival.(5)Spatial dynamics and distribution pattern of metapopulation are profoundly influenced by time-lagged niche construction.(6)Metapopulation size can reach a fixed level in the recency effect and equal weighting of time lag but is statistical stability in primacy effect, which implies the primacy effect is most remarkable.(7)The increment in the relative weightingof each generation\' niche construction and the length of time lag are significant factors for system destabilization.(8)Moderate capacity of positive niche construction benefits the metapopulation persistence.(9)The narrowing of niche breadth can decrease the metapopulation size and thereby increase the extinction risk.(10)The coupled function of time lag and niche construction make the system oscillation and generate the spiral wave, spiral-broken and circular wave in heterogeneous habitat.The spatial distributions of metapopulation and resource content are complementary due to a phase lag of their both frequencies.(12)Metapopulation persistence with niche construction depends not only on the balance between colonization and extinction, but also on the balance between the ability of niche construction and natural dissipation of habitat.(13)Metapopula-tion can survive under certain condition when the percent of suitable patches in habitat is lower than the ration of extinction to colonization.(14)Two thresholds exist in the process of transition of habitat quality dynamics from unsuitable to suitable, which include the intensity of niche construction and the initial condition of system.(15)Metapopulation size is positive correlated with the ability of positive niche construction, which means that organism or population who has strongly positive influences on their environment plays an important role to maintain the available habitat.

通过上述几个方面的研究，主要得出以下15条结论：(1)生态位构建可使空间结构种群，甚至是在没有杂合子优势的条件下，形成多种可能的稳定基因型分布模式；(2)随着环境的破坏与恶化，种群的生态位构建作用加速其较早形成稳定多态以阻碍环境对种群的不利影响，解释了有机体在不利环境下的一种生活史对策；(3)生态位构建作用通过基因型—环境反馈机制及有限的基因交流导致基因型多态的稳定共存；(4)有机体的生态位构建作用是一种积极的动力改变环境进而改变其自然选择的方向；(5)生态位构建的时滞作用对集合种群动态和空间分布产生深刻影响；(6)集合种群大小在时滞的崭新效应和等权重效应下达到一固定值，而在首位效应下达到统计稳定，表明首位效应的影响最显著；(7)首位效应下生态位构建相对权重的增量和时滞的长度是影响系统不稳定性动态的关键因素；(8)适中的生态位构建强度有利于集合种群的续存；(9)生态位宽度变窄会减少集合种群的数量从而增加其灭绝风险；(10)时滞和生态位构建的双重作用使系统产生周期振荡，并在异质性环境中产生稳定的螺旋波，破碎的螺旋波和环形波三种分布模式；(11)集合种群与资源含量的空间分布因为相滞而互补；(12)具有生态位构建的集合种群续存不仅取决于侵占率与灭绝率之间的平衡，而且依赖于生态位构建能力同其生境的自然消耗速率之间的妥协；(13)当生境中适合侵占的斑块比例小于其侵占率与灭绝率之比时，生态位构建作用促使集合种群在一定条件下续存：(14)生境斑块的状态从不适合到适合转变过程中存在生态位构建强度和系统初始条件这两个阈值；(15)集合种群的大小同正生态位构建能力正相关，意味着对环境具有较强正作用的有机体对维持有效生境起积极作用。

All of these were composed of plants adapted to the difficult conditions due to the clayey chalk support composed by the rubble.

所有的这些树林都是由这些适应了不利立地条件的植物组成，不利的立地条件也是那些由废渣碎石产生的粘土状的白垩导致的。

This paper outlines the history and present situation of grape culture in Zhejiang, advocating the necessity of reestablishing and extending graperies in this province.

本文概述了浙江葡萄栽培的历史与现状，提出恢复和发展葡萄生产的必要性，并且分析了浙江葡萄栽培的有利与不利条件及其发展的可能性。

Variables such as value at risk (a measure of how much banks stand to lose if markets turn against them) and the ratio of risky assets to equity have been rising, suggesting that investment banks' returns have been souped up by trading with borrowed money.

一些数值如在险价值(VAR 一种测量银行在市场不利条件下最大损失的指标)和风险资产与股权的比值在增加，暗示这些投行的收入增长来自于他们在用贷款作交易。

Therefore, in the design , two measures had been taken (1) under the diaphragm wall, connection of grouting curtain, whereby within foundation pit, drainage pressure reducing holes were placed, while stabilized grouting is adopted for grouting curtain.

施工期基底封水排水降水存在着基岩裂隙发育及基础上部为流塑状淤泥亚粘土等不利条件。

Ndead acolytes need to be better protected, because they have a huge disadvantage in getting and holding expansions in late game maybe give working acolytes 100 more hp?

D的寺僧需要更好的保护，因为他们在后期的扩展有巨大的不利条件（可能给工作中的寺僧+100血？

Based on the basic principles of gas-druven heat pumps,combined with present biogas utilization in china,the possibility in detail that biogas replaced natural gas as working medium of gas-driven heat pumps was discussed from advantages and handicaps.

从燃气热泵的工作原理入手，结合当前我国的沼气利用现状，从有利与不利条件两方面详细论述了沼气代替天然气作为燃气热泵驱动工质的可行性。

An unusually weak Dungeness crab harvest is compound ing the financial woes of West Coast fishermen who were already struggling with depressed consumer demand and the unprecedented collapse of the Pacific Chinook salmon fishery.

太平洋蟹歉收，西海岸经济低迷，消费需求降低，大马哈鱼产量锐减这些不利条件迫使依赖蟹和大马哈鱼的渔民们减小生产规模。

After using local materals with empty holes, cutting holes and delayed-action detonators, the efficiency of blasting has been improved.

在就地取材等不利条件下，通过布置空心眼、掏槽眼和采用延时雷管，提高了爆破效率。

We want to avoid decisive engagements under unfavourable conditions when we are not sure of victory, this being the policy we adopted in the Changteh and other campaigns.

而避免在不利条件下的无把握的决战，例如彰德等地战役所采的方针。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。