与直径和围长有关的图的最大亏格

利用图的直径和围长来研究图的最大亏格的下界,得到了如下结果：设G是直径为d的简单图,若G的围长不小于d（其中d为不小于3的整数）,则ξ（G）≤2,即γM（G）≥1/2β（G）-1．而且,在这种意义下,所得到的界是最好的．     

Wolbachia-based biocontrol for dengue reduction using dynamic optimization approach

Aedes aegypti females mosquitoes are the principal transmitters of dengue and other arboviral infections. In recent years, it was disclosed that, when deliberately infected with Wolbachia symbiont, this mosquito species loses its vectorial competence and becomes less capable of transmitting the virus to human hosts. Thanks to this important discovery, Wolbachia-based biocontrol is now accepted as an ecologically friendly and potentially cost-effective method for prevention and control of dengue and other arboviral infections. In this paper, we propose a dengue transmission model that accounts for the presence of wild Aedes aegypti females and those deliberately infected with wMelPop Wolbachia strain, which is regarded as the best blocker of dengue and other arboviral infections. However, wMelPop strain of Wolbachia considerably reduces the individual fitness of mosquitoes, what makes rather challenging to achieve the gradual extrusion of wild mosquitoes and ensure their posterior replacement by Wolbachia-carriers. Nonetheless, this obstacle have been overcome by employing the optimal control approach for design of specific intervention programs based on daily releases of Wolbachia-carrying mosquitoes. The resulting optimal release programs ensure the population replacement and eventual local extinction of wild mosquitoes in the finite time and also entail a significant reduction in the number of expected dengue infections among human hosts under the long-term settings.     

新Dirichlet级数Σn=0∞aneλns收敛横坐标

本文给出新Dirichlet级数Σ_n=0^∞a_ne^λ_ns的收敛横坐标σ_c、一致收敛横坐标σ_u和绝对收敛横坐标σ_a的定义.通过指数λ_n和系数a_n的关系去估计三个横坐标,并补充证明两类Dirichlet级数Σ_n=0^∞a_ne^λ_ns和Σ_n=0^∞a_ne^-λ_ns的收敛条件是一致的.     

基于主成分分析的广东省邮电业发展状况研究

通过主成分分析方法,选取2006、2011和2016年广东省各市邮电业务数据,对广东省21个地级市的邮政和通信事业发展状况进行分析和发展水平层次划分,从时间和地域空间两个维度对广东省各地区邮电业发展情况进行排名分组.结果表明,当前广东省各地区邮电业发展状况存在显著的地区差异.     

代数体函数涉及重值的Borel点

研究了单位圆内代数体函数涉及重值的Borel点的存在性,利用型函数统一证明了单位圆内无穷级,有限正级和部分零级代数体函数存在涉及重值的Borel点,并对有限正级的代数体函数得到两个必要条件.     

随机加权U-过程的条件弱收敛

假定Ｆ是一个由函数组成的集合．在这篇文章中,我们研究了指标集Ｆ上２阶的随机加权Ｕ－过程的条件弱收敛性质,导出了Ｕ－过程的随机加权逼近．     

Birth-pulse models of Wolbachia-induced cytoplasmic incompatibility in mosquitoes for dengue virus control

Dengue fever, which affects more than 50 million people a year, is the most important arboviral disease in tropical countries. Mosquitoes are the principal vectors of the dengue virus but some endosymbiotic Wolbachia bacteria can stop the mosquitoes from reproducing and so interrupt virus transmission. A birth-pulse model of the spread of Wolbachia through a population of mosquitoes, incorporating the effects of cytoplasmic incompatibility (CI) and different density dependent death rate functions, is proposed. Strategies for either eradicating mosquitoes or using population replacement by substituting uninfected mosquitoes with infected ones for dengue virus prevention were modeled. A model with a strong density dependent death function shows that population replacement can be realized if the initial ratio of number of infected to the total number of mosquitoes exceeds a critical value, especially when transmission from mother to offspring is perfect. However, with a weak density dependent death function, population eradication becomes difficult as the system’s solutions are sensitive to initial values. Using numerical methods, it was shown that population eradication may be achieved regardless of the infection ratio only when parameters lie in particular regions and the initial density of uninfected is low enough.     

Complete and complete moment convergence for weighted sums of widely orthant dependent random variables

In this paper, we establish a complete convergence result and a complete moment convergence result for weighted sums of widely orthant dependent random variables under mild conditions. As corollaries, the corresponding results for weighted sums of extended negatively orthant dependent random variables are also obtained, which generalize and improve the related known works in the literature.     

Existence and non-existence of positive solutions of BVPs for fractional order elastic beam equations with a non-Caratheodory nonlinearity

In this article, the existence and non-existence results on positive solutions of two classes of boundary value problems for nonlinear singular fractional order elastic beam equations is established. Here f depends on x  x^′$x^{\prime }$ and x^″,f$x^{″}\text{,}f$ may be singular at t=0$t=0$ and t=1$t=1$ and f may be a non-Caratheodory function. The analysis relies on the well known Schauder’s fixed point theorem. By applying iterative techniques, results on the existence of positive solutions are obtained and the iterative scheme which starts off with zero function for approximating the solution is established. The iterative scheme obtained is very useful and feasible for computational purpose. Examples and their numerical simulation are presented to illustrate the main theorems. A conclusion section is also given at the end of this paper.     

Complete moment convergence for i.i.d. random variables

In the paper, the complete moment convergence is obtained for i.i.d. random variables such that all moments exist, but the moment generating function does not exist. The main results extend the related known works due to Gut and Stadtmüller.