we characterize the rational subsets of a finite group and discuss the relations to integral cayley graphs.

We study the chromatic polynomials (= zero-temperature antiferromagnetic Potts-model partition functions) PG(q) for m × n rectangular subsets of the square lattice, with m ≤ 8 (free or periodic transverse boundary conditions) and n arbitrary (free longitudinal boundary conditions), using a transfer matrix in the Fortuin-Kasteleyn representation. In particular, we extract the limiting curves of ...

Introduction: Quantitative evaluation is recommended to improve diagnostic ability and serial assessment of dopamine transporter (DAT) density scans. We decided to compare the ordered subsets expectation-maximization (OSEM) with filtered back-projection (FBP), and to investigate the impact of different iteration and cut-off frequencies on SBR values. Methods</stro...

Abstract. According to Thurston’s classification, the set of homotopy classes orientation-preserving homeomorphisms orientable surfaces is split into four disjoint subsets. A class from each subset characterized by existence a homeomorphism called canonical form, namely: periodic homeomorphism, reducible nonperiodic algebraically finite order, that not an and pseudo-Anosov homeomorphism. forms ...

in the present paper the linear oscillator in r3 with z =constanthas been considered. the aim is to determine the necessary conditions forthe persistence of periodic solutions under discontinuous perturbations. a newapproach based on a computational method has been used. at the end weapply our method on an example.

Staphylococcus aureus (S. aureus) is a dangerous pathogen and a leading cause of both nosocomial and community acquired bacterial infection worldwide. However, on the other hand, we are all exposed to this bacterium, often within the first hours of life, and usually manage to establish equilibrium and coexist with it. What does the adaptive immune system contribute toward lifelong control of S....

The well-known density theorem for one-dimensional Gabor systems of the form (e2Jl'imbx g(x-na)}m,nEZ, where g E L2(JR), states that a necessary and sufficient condition for the existence of such a systemwhQse linear span is dense in L2(R), or which forms a frame for L2(R), is that the density condition a b :s I is satisfied. The main goal of this paper is to study the analogous problem for Gab...

If G is a nite abelian group and n > 1 is an integer, we say that G is n-good, if from each factorizationG = A1A2 An of G into direct product of subsets, it follows that at least one of the subsets Ai is periodic, in the sense that there exists x 2 G feg such that xAi = Ai. In this paper, we shall study some 3-groups with respect to this property. Acta Mathematica Academiae Paedagogicae Ny regy...

Human brucellosis is a major health problem in developing countries. A number of patients with human brucellosis do not recover from the acute stage of the disease and pass into the chronic form. Since the pathophysiology of this change is not well understood, we studied the T-cell subsets during the acute, subacute and chronic forms of human brucellosis. In this study we found alterations...