The ability to create and hold a mental schema of an object is one of the milestones in cognitive development. Developmental scientists have named the behavioral manifestation of this competence object permanence. Convergent evidence indicates that frontal lobe maturation plays a critical role in the display of object permanence, but methodological and ethical constrains have made it difficult ...

A discrete non-autonomous SIRVS model with general incidence is obtained from a continuous model by applying Mickens non-standard discretization method. Conditions for the permanence and extinction of the disease and the stability of diseasefree solutions are obtained. It is also proved that, if the time step is sufficiently small, when we obtain extinction (respectively permanence) for the con...

Using stochastic differential equations with Lévy jumps, this paper studies the effect of environmental stochasticity and random catastrophes on the permanence of Lotka-Volterra facultative systems. Under certain simple assumptions, we establish the sufficient conditions for weak permanence in the mean and extinction of the non-autonomous system, respectively. In particular, a necessary and suf...

This paper is concerned with the permanence and extinction problem of enterprises cluster constituted by m satellite enterprises and a dominant enterprise. We present the model involving impulsive effect based on ecology theory, which effectively describe the competition and cooperation of enterprises cluster in real economic environment. Applying comparison theorem of impulsive differential eq...

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...