In this paper, we consider a class of multi-group SEIR epidemic models with stochastic perturbations. By the method of stochastic Lyapunov functions, we study their asymptotic behavior in terms of the intensity of the stochastic perturbations and the reproductive number R0. When the perturbations are sufficiently large, the exposed and infective components decay exponentially to zero whilst the...

We provide a global analysis of systems of within-host parasitic infections. The systems studied have parallel classes of different length of latently infected target cells. These systems can also be thought as systems arising from within-host parasitic systems with distributed continuous delays. We compute the basic reproduction ratio R0 for the systems under consideration. If R0< or =1 the pa...

We show that the Morita equivalences Cliff(4) ' H, Cliff(7) ' Cliff(−1), and Cliff(8) ' R arise from quantizing the Hamiltonian reductions R0|4//Spin(3), R//G2, and R0|8//Spin(7), respectively.

abstract the grasses cold tolerance is the most important limiting factor for its cultivation in temperate regions, so using cold tolerant cultivars is essential for grasses successful cultivation. in order to evaluation freezing stress tolerance of several species of grasses, this study was conducted in agricultural faculty of ferdowsi university of mashhad as a factorial complete randomized b...

A study was undertaken to establish the susceptibility of two recently colonized sand fly species, Phlebotomus perniciosus and P. papatasi to some insecticides. A laboratory colony of P. papatasi, unexposed to insecticides for a period of ten years, was used as reference strain. Bioassay tests were carried out according to the WHO standard protocols based on the mortality rates recorded at diff...

Background: There are several plant extractions which are being used for mosquito control. The aim of this study was to evaluate the efficacy of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under laboratory conditions. Methods: These tests were carried out using WHO recommended bioassay method for adult mosquitoes. Results: The extracts from blac...

As part of our continuing research on isoquinoline acaricidal drugs, this paper reports the preparation of a series of the 2-aryl-1-cyano-1,2,3,4-tetrahydroisoquinolines with various substituents on the N-phenyl ring, their in vitro acaricidal activities against Psoroptes cuniculi, a mange mite, and discusses their SAR as well. The structures of all compounds, including 12 new ones, were elucid...

The continuous culture of mosquitoes is a costly endeavor for vector biology laboratories. In addition to the resources that must be committed to colony maintenance, biological costs, including genetic drift and accidental colony loss, also can occur. Although alternatives do exist, their application to mosquitoes is limited. Mosquito cryopreservation remains elusive, and many important species...

Seventeen isolates ofMetarhizium anisopliae (Metschnikoff) Sorokin and three isolates of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) were evaluated for their pathogenicity to the adult pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), in the laboratory. Flies were contaminated with dry conidia through a velvet material wrapped around the inner s...