Abstract. In this paper we have considered a nonautonomous predator-prey model with time delay due to gestation, in which a disease that can be transmitted by contact spreads among the prey only. Here, we have established some sufficient conditions on the permanence of the system by using inequality analytical technique. By Lyapunov functional method, we have also obtained some sufficient condi...

abstract nowruzak (salvia leriifolia) of lamiaceae family has a good capability for domestication in khorasan’s natural habitats. in order to investigate the effect of sowing design and depth in seedling emergence and permanence, a split plot experiment based on a randomized complete block design was performed with three replications. results indicated sowing design in all three parameters, sow...

For a nonautonomous discrete SIQR model, we obtain conditions for permanence and extinction of the disease and we establish the global asymptotical stability when our conditions determine extinction. We also discuss the particular autonomous and periodic situations, where our conditions are sharp thresholds between permanence and extinction of the disease. AMS Subject Classifications: 92D30, 37...

In this paper, we derive some threshold conditions for permanence and extinction of diseases that can be described by a nonautonomous SEIRS epidemic model. Under the quite weak assumptions, we establish some sufficient conditions to prove the permanence and extinction of disease. Some new threshold values are determined.

In this paper, we consider a food-limited population model with delay and feedback control. By applying the comparison theorem of the differential equation and constructing a suitable Lyapunov functional, sufficient conditions which guarantee the permanence and existence of a unique globally attractive positive almost periodic solution of the system are obtained. Keywords—Almost periodic soluti...

the paper is concerning preliminary survey of qaradaq region of eastern azerbaijan in view of ecological, archaeological and ethnographic perspectives. the region under study is poor in fertile soil, underpopulated settlements and nomadic ubas being its dominant landscape. indeed, archaeological investigations show the lack of considerable archaeological records up to the iron age. the main sub...

This two-part article considers how digital culture has influenced ideas about permanence. It examines the change in collecting practices in one legal deposit library. The author considers how the idea of permanence, understood in cultural heritage terms, influences digital culture, and, thus, digital technology. The first part of the article addresses the concepts associated with permanence, d...

In this chapter we describe Theorema, a system for supporting mathematical proving by computer. The emphasis of the chapter is on showing how, in many situations, proving can be reduced to solving in algebraic domains. We first illustrate this by known techniques, in particular the Gröbner bases technique. Then we go into the details of describing the PCS technique, a new technique that is part...