We investigate the symmetry component of the center variety of polynomial differential systems, corresponding to systems with an axis of symmetry in the real plane. We give a general algorithm to find this component, compute its dimension and show that it is irreducible. We show that our methods provide a simple way to compute the radical of the ideal generated by the focus quantities and, ther...

This paper is concerned with the bifurcations of limit cycles in a quadratic reversible Lotka-Volterra system with two centers under quadratic perturbations. By studying the number of zeros of Abelian integral based on the geometric properties of some planar curves, we obtain the cyclicity of each periodic annulus of the system under quadratic perturbations is two, and the cyclicity of two peri...

ness organization lexicon Structure-preservation Metrical theory Equation of Structure-building Harmonic rule phonotactics and versus application alternations: strict structure-changing Optimality theory cyclicity operations

background: in this study, the presence of resistance to diclazuril, amprolium+ethopabate and salinomycin, representing some of the commonest anticoccidials in iran’s poultry industry, against three mixed eimeria field isolates were investigated. methods: three eimeria field isolates, collected from typical broiler farms in iran, were propagated once, inoculated to 480 broilers, comprising 30 c...

Environmental issues have become increasingly important in economic research and policy for sustainable development. Such issues are tracked by the Dow Jones Sustainable Indexes (DJSI) through financial market indexes that are derived from the Dow Jones Global Indexes. The environmental sustainability activities of firms are assessed using criteria in three areas, namely economic, environmental...