A nonautonomous Leslie-Gower type food chain model with time delays is investigated. It is proved the general nonautonomous system is permanent and globally asymptotically stable under some appropriate conditions. Furthermore, if the system is periodic one, some sufficient conditions are established, which guarantee the existence, uniqueness, and global asymptotic stability of a positive period...

In this paper, the results of Freedman and So (1985) on global stability and persistence of simple food chains are extended to general diffusive food chains. For global stability of the unique homogeneous positive steady state, our approach involves an application of the invariance principle of reaction-diffusion equations and the construction of a Liapunov functional. For persistence, we use t...

Media constantly refer of unscrupulous producers that adulterate, alter or replace premium products in food chains with the goal to maximize illegally profits. Food traceability is a central issue for the identification of improper labeling of processed food and feed and there are rules aimed to protect consumers and producers against fraudulent substitution of quality products in food chain, b...

godina XVIII (2016.) ■ rujan listopad ■ broj 5 ■ MESO ■ 445 INTRODUCTION The common use of “value-based food chain (VBFC)” terminology can be found in the recent European scientific literature (Pirog and Bregendhal, 2012; European Parliament, 2013). Vacas et al. (2014) explained positive direct and indirect socio-economic effects of VBFC in increasing the local economy and community, such as hi...

The stability of ecological communities largely depends on the strength of interactions between predators and their prey. Here we show that these interaction strengths are structured nonrandomly in a large Caribbean marine food web. Specifically, the cooccurrence of strong interactions on two consecutive levels of food chains occurs less frequently than expected by chance. Even when they occur,...

Certain inventory items are living organisms, for example livestock, and are therefore capable of growing during the replenishment cycle. These items often serve as various saleable food items downstream in supply chains. The purpose of this paper is to develop a lot sizing model for growing items if the supplier of the items offers incremental quantity discounts. A mathematical model is derive...

Abstract One might reasonably invoke Dickens in describing AFSs and AVCs today: “it was the best of times, it worst times.”