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Type Problem (type + problem)
Selected AbstractsBlow-up analysis, existence and qualitative properties of solutions for the two-dimensional Emden,Fowler equation with singular potentialMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 18 2007Daniele Bartolucci Abstract Motivated by the study of a two-dimensional point vortex model, we analyse the following Emden,Fowler type problem with singular potential: where V(x) = K(x)/|x|2, with ,,(0, 1), 0 Properly colored subgraphs and rainbow subgraphs in edge-colorings with local constraintsRANDOM STRUCTURES AND ALGORITHMS, Issue 4 2003Noga Alon We consider a canonical Ramsey type problem. An edge-coloring of a graph is called m-good if each color appears at most m times at each vertex. Fixing a graph G and a positive integer m, let f(m, G) denote the smallest n such that every m -good edge-coloring of Kn yields a properly edge-colored copy of G, and let g(m, G) denote the smallest n such that every m -good edge-coloring of Kn yields a rainbow copy of G. We give bounds on f(m, G) and g(m, G). For complete graphs G = Kt, we have c1mt2/ln t , f(m, Kt) , c2mt2, and cmt3/ln t , g(m, Kt) , cmt3/ln t, where c1, c2, c, c are absolute constants. We also give bounds on f(m, G) and g(m, G) for general graphs G in terms of degrees in G. In particular, we show that for fixed m and d, and all sufficiently large n compared to m and d, f(m, G) = n for all graphs G with n vertices and maximum degree at most d. © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 2003 [source] Some results on the accuracy of an edge-based finite volume formulation for the solution of elliptic problems in non-homogeneous and non-isotropic mediaINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2009Darlan Karlo Elisiário de Carvalho Abstract The numerical simulation of elliptic type problems in strongly heterogeneous and anisotropic media represents a great challenge from mathematical and numerical point of views. The simulation of flows in non-homogeneous and non-isotropic porous media with full tensor diffusion coefficients, which is a common situation associated with the miscible displacement of contaminants in aquifers and the immiscible and incompressible two-phase flow of oil and water in petroleum reservoirs, involves the numerical solution of an elliptic type equation in which the diffusion coefficient can be discontinuous, varying orders of magnitude within short distances. In the present work, we present a vertex-centered edge-based finite volume method (EBFV) with median dual control volumes built over a primal mesh. This formulation is capable of handling the heterogeneous and anisotropic media using structured or unstructured, triangular or quadrilateral meshes. In the EBFV method, the discretization of the diffusion term is performed using a node-centered discretization implemented in two loops over the edges of the primary mesh. This formulation guarantees local conservation for problems with discontinuous coefficients, keeping second-order accuracy for smooth solutions on general triangular and orthogonal quadrilateral meshes. In order to show the convergence behavior of the proposed EBFV procedure, we solve three benchmark problems including full tensor, material heterogeneity and distributed source terms. For these three examples, numerical results compare favorably with others found in literature. A fourth problem, with highly non-smooth solution, has been included showing that the EBFV needs further improvement to formally guarantee monotonic solutions in such cases. Copyright © 2008 John Wiley & Sons, Ltd. [source] The psychosocial impact of parental cancer on children and adolescents: a systematic reviewPSYCHO-ONCOLOGY, Issue 2 2007Tessa Osborn Abstract This review aimed to identify (i) whether early stage parental cancer is associated with an increased risk of psychosocial difficulties amongst children and adolescents; (ii) which factors are associated with variations in psychosocial functioning amongst these children and adolescents. Searches of four electronic databases and the reference lists of relevant articles revealed 10 studies which satisfied the inclusion criteria for the first review question and thirteen studies for the second. Limitations in methodological quality and modest numbers of studies examining the same variables, restricted the conclusions which could be drawn. Overall, the evidence suggests that children and adolescents do not generally experience elevated levels of serious psychosocial difficulties compared to reference groups, but they are at a slightly increased risk for internalising type problems. Adolescent daughters appear to be the most negatively affected group. The prevalent use of measures of child psychopathology may be masking more context-specific problems and lower levels of distress. Family variables, especially family communication/expressiveness, are consistently associated with child/adolescent psychosocial functioning and there is suggestive evidence for the role of maternal depression/adjustment and parenting variables. There is little evidence that medical/treatment variables are important predictors of child outcomes. These findings have implications for identifying families with children most in need of support and indicating variables to target in interventions. Copyright © 2007 John Wiley & Sons, Ltd. [source]
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