Who cares for the nation’s infants and toddlers? For one of every two childre n under age three whose mother works, the face of the caregiver belongs to a family member—a parent or a relative. This pattern has held steady for decades, despite dramatic changes in families and child care options. Mothers (and grandmothers) have increasingly entered the labor forc e , d i v o rce and single parent...

In this contribution we apply different approaches to solve four rather different MINLP problems: special extensions to time-indexed formulations of production planning problems, a production planning problem in BASF’s petrochemical division, a site analysis of one of BASF’s bigger sites, and a process design problem. The first problem is related to a useful nonlinear extension of production pl...

uml is known as one of the most common methods in software engineering.since this language is semi-formal, many researches and efforts have beenperformed to transform this language into formal methods including petri nets.thus, the operation of verification and validation of the qualitative and nonfunctionalparameters could be achieved with more ability. since the majority of thereal world info...

graham higman has defined coset diagrams for psl(2,ℤ). these diagrams are composed of fragments, and the fragments are further composed of two or more circuits. q. mushtaq has proved in 1983 that existence of a certain fragment γ of a coset diagram in a coset diagram is a polynomial f in ℤ[z]. higman has conjectured that, the polynomials related to the fragments are monic and for a fixed degree...

In (Golchin A. and Rezaei P., Subpullbacks and flatness properties of S-posets. Comm. Algebra. 37: 1995-2007 (2009)) study was initiated of flatness properties of right -posets  over a pomonoid  that can be described by surjectivity of  corresponding to certain (sub)pullback diagrams and new properties such as  and  were discovered. In this article first of all we describe po-flatness propertie...