University of Memphis

About: University of Memphis is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 7710 authors who have published 20082 publications receiving 611618 citations. The organization is also known as: U of M.

Volume tracking of interfaces having surface tension in two and three dimensions

Abstract: Solution algorithms are presented for tracking interfaces with piecewise linear (PLIC) volume-of-fluid (VOF) methods on fixed (Eulerian) two-dimensional (2-D) structured and three-dimensional (3-D) structured and unstructured grids. We review the theory of volume tracking methods, derive appropriate volume evolution equations, identify and present solutions to the basic geometric functions needed for interface reconstruction and volume fluxing, and provide detailed algorithm templates for modern 2-D and 3-D PLIC VOF interface tracking methods. We discuss some key outstanding issues for PLIC VOF methods, namely the method used for time integration of fluid volumes (operator splitting, unsplit, Runge-Kutta, etc.) and the estimation of interface normals. We also present our latest developments in the continuum surface force (CSF) model for surface tension, namely extension to 3-D and variable surface tension effects. We identify and focus on key outstanding CSF model issues that become especially critical on fine meshes with high density ratio interfacial flows, namely the surface delta function approximation, the estimation of interfacial curvature, and the continuum surface force scaling and/or smoothing model. Numerical results in two and three dimensions are used to illustrate the properties of these methods.

Action Dynamics Reveal Parallel Competition in Decision Making

Abstract: When deciding between two alternatives, such as whether toorder the pasta or the chicken, or whether to pursue a career inacademia or industry, a person may feel torn—as if the optionsliterally pull him or her in two directions. This metaphor mayhavesomesurprisingliteraltruth.Ifasked,forexample,whether‘‘murder is sometimes justified,’’ individuals may be inclined toboth agree and disagree with the statement. Here, we document,for the first time, the pull toward contrasting responses duringevaluative thinking, reporting the results of a study examiningthe trajectory of participants’ reaching movements toward dif-ferent response options.Our results suggest that a decision process is not necessarilycompleted inthe brain’scognitivesubsystems before itissharedwith other subsystems, as has been traditionally assumed.Rather,simultaneous‘‘pull’’frommultipleresponsealternativesseemstoinfluencetheexecutionofmovementitself.Thisfindingsuggests that a dynamic approach to mental processing—anapproach that has already provided descriptions of perception,attention,andcategorization (e.g.,AbramsBGoldSGratton,Coles,Sirevaag,Eriksen,D Hovland & Sears, 1938; McClelland & Rogers, 2003;Spivey, 2007; Tipper, Howard, & Houghton, 1999)—may shednew light on high-level cognition (Roe, Busemeyer, & Town-send, 2001; Townsend & Busemeyer, 1989).

Fuzziness in Geographical Information Systems: contributions from the analytic hierarchy process†

Abstract: Recent developments in geographical information systems have drawn upon concepts of fuzzy set theory and multi-criteria methodology. In this paper we argue that there is a method, Saaty’s Analytic Hierarchy Process (AHP), that is compatible with both these research directions. The contributions of the AHP are highlighted in the light of recent developments in GIS, with particular attention to the concept of fuzzy set theory. An example of a GIS application is provided to show how the AHP can deal operationally with fuzziness, factor diversity and complexity in problems of land evaluation involving the location of a public facility.

Genome of the Asian longhorned beetle (Anoplophora glabripennis), a globally significant invasive species, reveals key functional and evolutionary innovations at the beetle–plant interface

Abstract: Relatively little is known about the genomic basis and evolution of wood-feeding in beetles. We undertook genome sequencing and annotation, gene expression assays, studies of plant cell wall degrading enzymes, and other functional and comparative studies of the Asian longhorned beetle, Anoplophora glabripennis, a globally significant invasive species capable of inflicting severe feeding damage on many important tree species. Complementary studies of genes encoding enzymes involved in digestion of woody plant tissues or detoxification of plant allelochemicals were undertaken with the genomes of 14 additional insects, including the newly sequenced emerald ash borer and bull-headed dung beetle. The Asian longhorned beetle genome encodes a uniquely diverse arsenal of enzymes that can degrade the main polysaccharide networks in plant cell walls, detoxify plant allelochemicals, and otherwise facilitate feeding on woody plants. It has the metabolic plasticity needed to feed on diverse plant species, contributing to its highly invasive nature. Large expansions of chemosensory genes involved in the reception of pheromones and plant kairomones are consistent with the complexity of chemical cues it uses to find host plants and mates. Amplification and functional divergence of genes associated with specialized feeding on plants, including genes originally obtained via horizontal gene transfer from fungi and bacteria, contributed to the addition, expansion, and enhancement of the metabolic repertoire of the Asian longhorned beetle, certain other phytophagous beetles, and to a lesser degree, other phytophagous insects. Our results thus begin to establish a genomic basis for the evolutionary success of beetles on plants.