Improved numerical methods for turbulent viscous recirculating flows

The hybrid-upwind finite difference schemes employed in generally available combustor codes possess excessive numerical diffusion errors which preclude accurate quantative calculations. The present study has as its primary objective the identification and assessment of an improved solution algorithm as well as discretization schemes applicable to analysis of turbulent viscous recirculating flows. The assessment is carried out primarily in two dimensional/axisymetric geometries with a view to identifying an appropriate technique to be incorporated in a three-dimensional code

FIRMS, INCENTIVES, AND THE SUPPLY OF FOOD SAFETY: A FORMAL MODEL OF GOVERNMENT ENFORCEMENT

Recent instances of significant food safety breeches in both meat and biotechnology challenge traditional safety efforts. A formal model utilizing agency theory is used to explore the power relationships between the regulator and the firm. Fundamental issues effecting firms' supply of safety are demonstrated and alternative corrective mechanisms are discussed.Food Consumption/Nutrition/Food Safety,

FOOD SAFETY IN THE MEAT INDUSTRY: A REGULATORY QUAGMIRE

Food Consumption/Nutrition/Food Safety, Livestock Production/Industries,

Neutralino Dark Matter in the Left-Right Supersymmetric Model

We study the neutralino sector of the left-right supersymmetric model. In addition to the possibilities available in the minimal supersymmetric model, the neutralino states can be superpartners of the U(1)_{B-L} gauge boson, the neutral SU(2)_R neutral gauge boson, or of the Higgs triplets. We analyze neutralino masses and determine the parameter regions for which the lightest neutralino can be one of the new pure states. We then calculate the relic density of the dark matter for each of these states and impose the constraints coming from the rho parameter, the anomalous magnetic moment of the muon, b -> s gamma, as well as general supersymmetric mass bounds. The lightest neutralino can be the bino, or the right-wino, or the neutral triplet higgsino, all of which have different couplings to the standard model particles from the usual neutralinos. A light bino satisfies all the experimental constraints and would be the preferred dark matter candidate for light supersymmetric scalar masses, while the right-wino would be favored by intermediate supersymmetric mass scales. The neutral triplet Higgs fermion satisfies the experimental bounds only in a small region of the parameter space, for intermediate to heavy supersymmetric scalar masses.Comment: 31 pages, 8 figures, one table and references added, to be published in Phys. Rev.

"You Know You Are Sick, Why Do You Carry A Pregnancy Again?" Applying the Socio-Ecological Model to Understand Barriers to PMTCT Service Utilization in Western Kenya.

ObjectiveThroughout most of sub-Saharan Africa (SSA), prevention of mother-to-child transmission (PMTCT) services are readily available. However, PMTCT programs in SSA have had suboptimal performance compared to other regions of the world. The main objective of this study is to explore the socio-ecological and individual factors influencing the utilization of PMTCT services among HIV-positive pregnant women in western Kenya using a social ecological model as our analytical lens.MethodsData were collected using in-depth interviews with 33 HIV-infected women attending government health facilities in rural western Kenya. Women with HIV-infected infants aged between 6 weeks to 6 months with a definitive diagnosis of HIV in the infant, as well as those with an HIV-negative test result in the infant were interviewed between November 2012 and June 2013. Coding and analysis of the transcripts followed grounded theory tenets. Coding reports were discussed in a series of meetings held among the authors. We then employed constant comparative analysis to discover dominant individual, family, society and structural determinants of PMTCT use.ResultsBarriers to women's utilization of PMTCT services fell within the broad constructs of the socio-ecological model of individual, family, society and structural determinants. Several themes cut across the different steps of PMTCT cascade and relate to different constructs of the socio-ecological model. These themes include: self-motivation, confidence and resilience, family support, absence or reduced stigma, right provider attitude and quality of health services provided. We also found out that these factors ensured enhanced maternal health and HIV negative children.ConclusionThe findings of this study suggest that a woman's social environment is an important determinant of MTCT. PMTCT Interventions must comprehensively address multiple factors across the different ecological levels. More research is however required for the development of multi-component interventions that combine strategies at different ecological levels

General Complementarities on Complete Partial Orders

Cataloged from PDF version of article.This paper proves the existence of a Nash equilibrium for extended (semi-) uniform g-modular games, i.e., non-cooperative games where the strategy space is a complete partially ordered set, and the best reply correspondence satisfies certain monotonicity requirements

Sneutrino Dark Matter: Symmetry Protection and Cosmic Ray Anomalies

We present an R-parity conserving model of sneutrino dark matter within a Higgs-philic U(1)' extension of the minimal supersymmetric standard model. In this theory, the mu parameter and light Dirac neutrino masses are generated naturally upon the breaking of the U(1)' gauge symmetry. The leptonic and hadronic decays of sneutrinos in this model, taken to be the lightest and next-to-lightest superpartners, allow for a natural fit to the recent results reported by the PAMELA experiment.Comment: Revised to match the published version; 11 pages (2 column format), 1 table, 6 figures, to appear in PR

Signatures for doubly-charged Higgsinos at colliders

Several supersymmetric models with extended gauge structures predict light doubly-charged Higgsinos. Their distinctive signature at the large hadron collider is highlighted by studying their production and decay characteristics.Comment: 3 pages, 4 figures, Latex. Submitted for SUSY 2008 proceeding

CP-Odd Phase Effects in a Left-Right Symmetric Chargino Sector

The left-right supersymmetric model contains a right-handed gaugino, as well as several higgsinos, in addition to the minimal supersymmetric model. Thus several CP-noninvariant phases appear in this sector. We analyze their impact on chargino masses and find that only two combinations are physically relevant. We then study the production of charginos in e+e- annihilation and chargino decays into a sneutrino and a lepton, and investigate the effects of CP-phases. We also study the CP-odd asymmetry in the production and subsequent decay at the linear collider with longitudinally polarized beams and find a large enhancement when the decay channel to the right sneutrino is available. The effects of the phases in the left-right supersymmetric chargino sector are different from the minimal supersymmetric standard model, and signals from this sector would be able to distinguish between different gauge symmetries.Comment: 24 pages, 11 figures, minor clarifications in the model part, to be published in Phys. Rev.