查询词典 predator

A predator model with refuge and toxicity is studied. By constructing a suitable Dulac function, it is shown that there is no limit cycle in the first quadrant, thus the globally stability of the equilibrium is proved. Further more, the paper analyzes the influence of refuge, toxicity and harvesting. It is amazing that ① if the death rate of predator is big or the harvesting effort is big, the existence of the predator is unrelated with refuge; if the death rate of predator and the harvesting effort are small, and the refuge is small enough, the population of both species is increased as the increase of refuge;② if d2=0, the increase of d1 has no influence on the prey population, while the population of predator is decreased.

研究一类有避难所、毒素作用和外界捕获影响的捕食系统，通过构造恰当的Dulac函数，证明系统在第一象限没有极限环，从而证明了平衡点的全局稳定性；分析了避难所、毒素、捕获作用对该系统最终种群数量的影响，发现：①当捕食者的死亡率大或其被捕获得多时，两种群的绝灭与避难所的存在无关；当捕食者的死亡率小、被捕获得多且避难所足够小时，随着食饵避难所的增加，捕食者种群数量也随之增加；②当毒素d2=0时，毒素d1的增加对食饵种群最终数量没有影响，而使捕食者种群数量下降。

This paper includes four chapters,the first part is an introduction,the second part is concerned with the state of construct and improvement about the predator-prey sys-tem,the third part is concerned with the state of research about the predator-prey system. Some new directions of predator-prey system are introduced in brief in the fourth part.

本文共分四部分：第一部分是引言；第二部分介绍了捕食者-食饵系统的建立和发展现状；第三部分系统的阐述了捕食者-食饵系统的研究情况；第四部介绍了捕食系统的一些其它的研究方向。

We also conclude that the equilibrium of the prey population will be enlarged due to the Allee effect of the predator, but the Allee effects of the prey may decrease the equilibrium value of the predator, or that of both the predator and prey.

如果捕食者受Allee效应的影响，则猎物种群在平衡点的密度将增大；但是猎物的Allee效应将同时减小捕食者和猎物在平衡点的密度，或者减少捕食者在平衡点的密度。

At a certain range, habitat loss and its spatial structure can benefit the control of the epidemic disease, which indicates the possibility of using human disturbance in habitat as a potential epidemic-control method in conservation.(6) Not only the quantity of habitat loss but also the spatial correlations of patch types caused by nonrandom habitat loss affect the invasion and transmission of disease. More fragmented landscape (high amount of habitat loss, low clustering of lost patches) hinders the parasitic infection, which also indicates that whether the spatial heterogeneity benefits or hinders the invasion is dependent on the considered ecological process.(7) Two components of the spatial heterogeneity (the amount and spatial autocorrelation of the lost habitat) form a trade-off in determining the host-parasite dynamics.(8) Within a certain range of habitat loss, host can counterbalance the positive and negative effects, and shows a rising tendency.(9) The epidemic is more likely to break out in the prey-predator system if only a small amount of habitat loss.(10) A highly aggregated distribution of species is a common behavioral strategy when dealing with habitat loss or other environmental stresses.(11) The parasite-host/prey-predator eco-epidemiological systems have the similar mechanism with the intraguild predation systems, and the predator acts as the intraguild predation, the infected prey acts as intraguild prey, and the susceptible prey acts as shared resource.(12) Species at the highest trophic level are no longer affected the most by habitat loss, which depend not only on the biological mechanism but also on the external environmental disturbances.

随着邻体数目的增加，病毒的感染力度变得更大而且在空间上形成聚集的波形；(5)生境破坏及其空间结构在一定范围内有利于疾病的控制，这暗示人为对生境的干扰可作为疾病控制的一个潜在方法；(6)生境破坏的数量以及不同类型生境的空间分布格局都显著地影响了寄生病毒的入侵和传播，生境破碎化程度越高(高丧失斑块的数量或低聚集程度)，将越有害于病毒的入侵和传播，这暗示了空间异质性是否有益于物种的入侵依赖于所考虑的生态过程；(7)由生境破坏引起的空间异质性的两个组分之间存在负偶联关系trade-off(8在适度的生境破坏范围内，宿主种群能够平衡生境破坏带来的正负两种效应并呈现增长趋势；(9)在捕食-食饵系统中，寄生感染病毒极有可能在生境破坏量较低时爆发；(10)物种在面临生境破坏或者其它环境压力时表现出更高的聚集分布策略；(11)寄生-宿主/食饵-捕食生态传染病系统与共位捕食食物网结构具有相似的生物机制，其中捕食者扮演共位捕食者的角色，已感染食饵作为共位食饵，易感染食饵扮作共同消耗的资源；(12)位于最高营养级水平的种群对生境破坏的响应不一定是最敏感的，这不仅依赖于内在的生物机制同时也依赖于外在的环境干扰。

This paper consists of three parts: Firstly, we discuss a nonautonomous -species two-patches cooperative Lotka-Volterra diffusion system. Using Brouwer fixed-point theory and Liapunov function, under some conditions, we obtain that the system has a unique globally asymptotically stable positive periodic solution. Secondly, we consider a kind of nonautonomous predator-prey model, in which preys are with stage structure and the predator are with two patches.

中文摘要：本文分三部分讨论三类生态模型周期解或概周期解的存在性及全局渐近稳定性等内容：第一部分讨论了两斑块种群的互惠Lotka-Volterra扩散系统，运用不动点理论和构造Liapunov函数，得到了系统存在唯一一个全局渐近稳定的正周期解的充分条件。

And we really wanted the bongo drums for predator, so make sure on all the key moments on all the predator shots that you get that.

我们真的希望邦戈鼓为捕食者，因此要确保所有的关键时刻，对所有的捕食者枪，你得到的。

Considering a predator-prey system with a kind functional reaction in which the predator species have no density restriction,no fishing,while the prey species have nonlinear density restriction and the constant invest.

考虑捕食者无密度制约、无捕捞，而食饵具有非线性密度制约和常投放率的一类功能性反应的食饵捕食系统，对其进行了定性分析，证明了在不稳定的正平衡点附近存在唯一的极限环。

Six months after the introduction of the predator, Losos found that the Anolis population had dropped by half or more on the islands with the predators, and in comparison to the lizards on the predator-free islands, long legs were more strongly favored: Survivors had longer legs relative to non-survivors.

在引进掠食者的六个月后，Losos发现，有掠食者的六个小岛上的Anolis数量下降一半或更多，对比之下，没有掠食者的岛上，长肢品种更占优势：生存者的四肢长度比死亡者的更长。

Shock Till You Drop 休克直至你辍学 has learned from an anonymous source at Twentieth Century Fox that a third chapter in the Alien vs. Predator franchise is a "certainty." At this point, it is unknown if brothers Colin and Greg Strause, who helmed Aliens vs Predator - Requiem , will be involved with the sequel.

获悉，从匿名消息来源在二十世纪福克斯电影公司表示，第三章，在与外国人的捕食者专营权是一个&肯定&，在这一点上，它是未知的，如果兄弟科林和Greg斯塔劳斯，他们带领外国人与捕食者-安魂曲，将涉及与续集。

The inducible nitric oxide synthase is obviously expressed in speen of rats under the predator stress, suggesting important function for iNOS in speen physiology. However, the expression and subcellular localization for NOS in speen development and differentiation are largely unknown. In the present study, the changes in iNOS activity in spleen of rats under predator stress were studied to explore the role of iNOS in the decreased immunoactivity of the stressed rats. The changes in iNOS were observed with immunobistochemical method, and the contents of NOS and NO in spleen with biochemical method.

在捕食压力下，大鼠脾脏诱导型一氧化氮合酶明显表达，说明iNOS起到了重要的生理功能，然而，NOS的表达及在亚细胞水平的定位以及相应的差异变化等都很不明确，本试验采用捕食应激模型，利用免疫组织化学方法和生化测定，检测心理性应激对大鼠脾脏iNOS活性的影响及探讨这种影响与应激动物免疫力下降之间的关系。

For the head-teacher of the class said that I had seriously broken the school rules,which led me to a three-day suspend class.

为什么呢？因为我的班主任说我严重的违反了校规，于是让我停课三天。

Many of them believe that the conversion of thousands of working-class folk in England spared that nation from the mass carnage and the tyranny that came with the revolution in France.

他们之中有许多人相信，在英国数以千计的劳工阶级之悔改信主使英国免於遭受如法国大革命所造成的大屠杀和专制暴政。