In this paper, a class of predator-prey model with prey competition is proposed, in which the interactions of predation between predator and prey are randomised and subsequently evaluated under Markovian switching. By constructing appropriate Lyapunov functions and applying various analytical methods, sufficient conditions for the existence of unique global positive solution, stochastic permane...

Fourteen-month-old infants saw an object hidden inside a container and were removed from the disappearance locale for 24 hr. Upon their return, they searched correctly for the hidden object, demonstrating object permanence and long-term memory. Control infants who saw no disappearance did not search. In Experiment 2, infants returned to see the container either in the same or a different room. ...

OBJECTIVE Changes in defense mechanisms after treatment of patients with obsessive-compulsive disorder (OCD) were measured by using an established rating scale. METHOD Before and after 7-week group behavior therapy, 17 patients with DSM-III-R OCD were assessed with the Defense Style Questionnaire, Yale-Brown Obsessive Compulsive Scale, and Beck Depression Inventory. RESULTS After behavior t...

A series of 9 search tasks corresponding to the Piagetian Stages 3-6 of object permanence were administered to 11 common marmosets (Callithrix jacchus). Success rates varied strongly among tasks and marmosets, but the performances of most subjects were above chance level on the majority of tasks of visible and invisible displacements. Although up to 24 trials were administered in the tests, sub...

We consider ecological difference equations of the form xt+1 = x i tAi(xt), where x i t is a vector of densities corresponding to the subpopulations of species i (e.g., subpopulations of different ages or living in different patches), xt = (xt , x 2 t , . . . , x m t ) is the state of the entire community, and Ai(xt) are matrices determining the update rule for species i. These equations are pe...

In this article, we study the global dynamics of a discrete two-dimensional competition model. We give sufficient conditions on the persistence of one species and the existence of local asymptotically stable interior period-2 orbit for this system. Moreover, we show that for a certain parameter range, there exists a compact interior attractor that attracts all interior points except Lebesgue me...

This paper presents a streamlined metadata record format designed to support the permanence of network discoverable objects. It starts with the Dublin Core consensus and distills out a subset of four semantic buckets − a metadata kernel − that balances the needs for adequate identification of persistent objects and for low cost metadata generation. To minimize the burden of creating, understand...

Abstract. We show that a bacteria and bacteriophage system with either a perfectly nested or a one-to-one infection network is permanent, a.k.a uniformly persistent, provided that bacteria that are superior competitors for nutrient devote the least to defence against infection and the virus that are the most efficient at infecting host have the smallest host range. By ensuring that the density-...

Verifiable criteria are established for the existence of positive periodic solutions and permanence of a delayed discrete periodic predator-prey model with Holling-type II functional response N1(k + 1) = N1(k)exp{b1(k)− a1(k)N1(k− [τ1])− α1(k)N2(k)/(N1(k) + m(k)N2(k))} and N2(k + 1) = N2(k)exp{−b2(k) + α2(k)N1(k − [τ2])/(N1(k − [τ2]) + m(k)N2(k− [τ2]))}. Our results show that the delays in the ...

Infants aged 3-5 months (mean of approximately 4 months) were given a novel anticipatory looking task to test object permanence understanding. They were trained to expect an experimenter to retrieve an object from behind a transparent screen upon hearing a cue ("Doors up, here comes the hand"). The experimenter then hid the object behind one of two opaque screens and after either 2 or 8s gave t...