Qualitative Analysis of a Diffusive Predator-prey Model with Nonlcoal Fear Effect

In this paper,we establish a delayed predator-prey model with nonlocal fear effect.Firstly,the existence,uniqueness,and persistence of solutions of the model are studied.Then,the local stability,Turing bifurcation,and Hopf bifurcation of the constant equilibrium state are analyzed by examining the characteristic equation.The global asymptotic stability of the positive equilibrium point is investigated using the Lyapunov function method.Finally,the correctness of the theoretical analysis results is verified through numerical simulations.

具有脉冲效应的Holling Ⅲ系统的动力行为

通过周期性释放天敌和化学控制的综合害虫管理(IPM)改进捕食者具有Holling型功能性反应系统:dx(t)dt=ax(t)-bx2(t)-xαx2(2t()t)+y(βt)2,dy(t)dt=-cy(t)+kxα2x(2t()t)+y(βt2).得到一个新的系统:dx(t)dt=ax(t)-bx2(t)-xαx2(2t()t)+y(βt)2,dy(t)dt=-cy(t)+kxα2x(2t()t)+y(βt2).t≠nT,ΔΔyx((tt))==--pp21yx((tt)),+q.t=nT.给出当q>0,0≤p1<1,0≤p2<1时,新系统的害虫周期全局渐近稳定性与新系统的持续生存条件.研究当q>0,0≤p1<1,0≤p2<1时,新系统正周期解的存在性和当q≡0,0<p1<1,0≤p2<1时,无捕食者周期解的存在性和稳定性.

隔断型军用车辆防雷座椅跌落试验研究

以某型车辆的座椅安装点冲击为输入条件,通过理论研究-仿真模拟-整车试验-跌落试验,进行刚性座椅和一种隔断型防雷座椅的跌落试验。试验研究发现:确定跌落试验边界条件时,刚性座椅的冲击速度应选择局部效应阶段的速度峰值;隔断型防雷座椅的冲击速度应选择爆炸全局效应阶段车辆整体上行的跳起速度。

社会网络区位关系累积与员工绩效关系的可行性研究

从社会资本角度分析社会网络区位关系累积的概念,提出区位关系局部和全局累积效应,并给出了全局累积效应的测量方法,从而为社会资本测量提供了新方法。把该测量与随机森林模型相结合应用于中小企业员工绩效影响因素研究,发现基于区位关系全局累积效应的全局社会资本比基于直接关系的社会资本对于员工绩效具有更好的解释力。

Application of stochastic method to optimum design of energy-efficient induction motors with a target of LCC

For an energy-efficient induction machine, the life-cycle cost (LCC) usually is the most important index to the consumer. With this target, the optimization design of a motor is a complex nonlinear problem with constraints. To solve the problem, the authors introduce a united random algorithm. At first, the problem is divided into two parts, the optimal rotor slots and the optimization of other dimensions. Before optimizing the rotor slots with genetic algorithm ( GA), the second part is solved with TABU algorithm to simplify the problem. The numerical results showed that this method is better than the method using a traditional algorithm.

长江经济带外向型经济空间溢出效应

长江经济带在中国区域发展布局中具有重要的战略地位,研究长江经济带分区及全局外向型经济的空间溢出效应既有利于提升上、中、下游地区的外向型经济发展水平,又能为长江经济带早日实现对外开放新格局提供借鉴。基于邻近关系、地理距离、经济引力模型的权重矩阵,构建空间计量模型,从全局和分区两个层面入手,探究2005-2017年长江经济带外向型经济的空间溢出效应。结果表明:①3种权重矩阵下,长江经济带外向型经济均表现出较强的空间集聚特征,但各市域外向型经济发展水平更倾向于受到相邻市域的影响。②从全局层面来看,长江经济带外向型经济具有显著的正向空间溢出效应,且第三产业比重提升是促进长江经济带外向型经济整体发展最显著的因素。③从分区层面看,上、中、下游地区外向型经济的主要影响因素不同。区域经济政策对上游地区外向型经济的提升作用最为显著;第三产业比重提升对中游地区外向型经济产生最积极的促进作用;交通连接度指数对下游地区的外向型经济产生最显著的正向影响。据此,提出促进长江经济带外向型经济发展的建议。

Dynamic global analysis of transcription reveals the role of mi RNAs in synergistic stabilization of gene expression

Buffering exogenous perturbation is crucial to maintain transcriptional homeostasis during development.While mi RNAs have been speculated to play a role in stability maintenance, previous studies seeking to check this conjecture focused on measurements of transcript levels at steady state or involved individual mi RNA targets. We measured whole-genome expression dynamics by introducing a transient perturbation and establishing a perturbation and recovery system in Drosophila larvae. We inhibited all transcription and assayed transcriptomes at several time points during recovery from inhibition. We performed these experiments in the wild type and mi RNA-deficient genetic backgrounds. Consistent with theories about mi RNAs’ function in stabilizing the transcriptome, we find that attenuating mi RNA expression leads to weak impairment in degradation of targets but strong destabilization of target genes when transcription is re-activated. We further fitted a model that captures the essential aspects of transcription dynamics in our experiments and found that the mi RNA target transcripts uniformly overshoot the original steady state as they recover from a general inhibition of transcription if global mi RNA levels are reduced. Collectively, our results provide experimental evidence for the idea that mi RNAs act cumulatively to stabilize the transcriptional regulatory network. We therefore found a promising approach to assess the effect of these molecules on transcription dynamics.

DYNAMICS OF A DIFFUSIVE PREDATOR-PREY MODEL WITH ADDITIVE ALLEE EFFECT

In this paper, we investigate the dynamics of a diffusive predator prey model with Holling-II functional response and the additive Allee effect in prey. We show the local and global asymptotical stability of the positive equilibrium, and give the conditions of the existence of the Hopf bifurcation. By carrying out global qualitative and bifurcation analysis, it is shown that the weak and strong Allee effects in prey can induce different dynamical behavior in the predator-prey model. Furthermore, we use some numerical simulations to illustrate the dynamics of the model. The results may be helpful for controlling and managing the predator-prey system.

The effect of diffusion loss on the time-varying giant Panda population

It has been certificated that corridors can help giant pandas to keep their habitat from fragmenting. However there are still losses during the process of moving along corridors. In this study, a mathematical model with Allee effect is carried out to describe the diffusion of giant pandas between n patches. Some criteria are obtained to keep the system persisting. It is proved that the system has a unique positive w-periodic solution which is globally asymptotically stable. The ecological meanings of these findings are discussed following the results. And some numerical simulations in the Qinling Mountain giant panda nature reservation area are also presented in the end.