1,333 research outputs found

    The Noncommutative Geometry of the Quantum Projective Plane

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    We study the spectral geometry of the quantum projective plane CP^2_q, a deformation of the complex projective plane CP^2, the simplest example of a spin^c manifold which is not spin. In particular, we construct a Dirac operator D which gives a 0^+ summable spectral triple, equivariant under U_q(su(3)). The square of D is a central element for which left and right actions on spinors coincide, a fact that is exploited to compute explicitly its spectrum.Comment: v2: 26 pages. Paper completely reorganized; no major change, several minor one

    Triggering Deep Convection with a Probabilistic Plume Model

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    A model unifying the representation of the planetary boundary layer and dry, shallow and deep convection, the Probabilistic Plume Model (PPM), is presented. Its capacity to reproduce the triggering of deep convection over land is analysed in detail. The model accurately reproduces the timing of shallow convection and of deep convection onset over land, which is a major issue in many current general climate models. The PPM is based on a distribution of plumes with varying thermodynamic states (potential temperature and specific humidity) induced by surface layer turbulence. Precipitation is computed by a simple ice microphysics, and with the onset of precipitation, downdrafts are initiated and lateral entrainment of environmental air into updrafts is reduced. The most buoyant updrafts are responsible for the triggering of moist convection, causing the rapid growth of clouds and precipitation. Organization of turbulence in the subcloud layer is induced by unsaturated downdrafts, and the effect of density currents is modeled through a reduction of the lateral entrainment. The reduction of entrainment induces further development from the precipitating congestus phase to full deep cumulonimbus. Model validation is performed by comparing cloud base, cloud top heights, timing of precipitation and environmental profiles against cloud resolving models and large-eddy simulations for two test cases. These comparisons demonstrate that PPM triggers deep convection at the proper time in the diurnal cycle, and produces reasonable precipitation. On the other hand, PPM underestimates cloud top height

    Experiences of gender-based violence in women asylum seekers from Honduras, El Salvador and Guatemala

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    Introduction: Every year, thousands of women flee gender-based violence in Honduras, El Salvador, and Guatemala (sometimes collectively referred to as the Northern Triangle) in an attempt to seek asylum in the United States. Once in the United States, their legal teams may refer them for a psychological evaluation as part of their application for asylum. Licensed clinicians conduct in-depth interviews in order to document the psychological impact of the reported human rights violations. Method: Using archival de-identified data from a human rights program, this study gathered the experiences of gender-based violence reported by 70 asylum-seeking women from Honduras, El Salvador, and Guatemala who participated in pro bono psychological evaluation. Descriptive data were analyzed using a modified consensual qualitative research (CQR-M) method.Results: These asylum seekers reported exposure to systemic violence, including severe intimate partner violence, as well as physical and sexual assaults, and threats of death by organized criminal groups in their communities. Additionally, over a third of women reported experiences of violence during their migration. The majority of asylum seekers endorsed symptoms associated with anxiety (80%) and depression (91%), as well as trauma-and stressor-related symptoms (80%). Discussion: The results of this study elucidate the manyforms of gender-based violence experienced by women in this region, the physical and psychological sequelae of this persecution, and the systemic forces that prevent them from remaining in their countries of origin. The research results also highlight the potential impact of trauma on the women’s ability to testify effectively during asylum legal hearings, elucidate factors that may contribute to their resilience in light of the human rights violations they survived, and suggest implications for clinical practice

    Comportamiento de colzas invernales frente a primaverales en Santa Rosa, La Pampa

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    El siguiente trabajo se realizó en el campo experimental de la Facultad de Agronomía de la Universidad Nacional de La Pampa, ubicado a 36° 46' de latitud sur, a 64° 16' de longitud oeste y a 210 msnm, en el ciclo 1996/97. El objetivo de este trabajo fue determinar el comportamiento de cultivares invernales frente a los cultivares primaverales que se encuentran actualmente en el mercado con la finalidad de detectar materiales invernales, que cumplan sus requerimientos ambientales en la región y como tales puedan potenciar el rendimiento, y garantizar un mejor comportamiento a frío. Se utilizó un diseño de bloques al azar donde se siguió el comportamiento fenológico de ocho cultivares de colza: Honk (invernal), lndol (invernal precoz), Liberty (invernal semiprecoz), Nolza 541 (primaveral), Nolza 53 (primaveral), Tomado (primaveral semiprecoz) Mari (primaveral semiprecoz), y Volean (primaveral precoz) en tres fechas de siembra. Se encontró que los cultivares invernales sembrados en fechas tempranas presentan un comportamiento igual o superior a los cultivares primaverales, no encontrándose el mismo resultado para fechas de siembra tardías, en donde los cultivares invernales no alcanzan la etapa reproductiva

    Effect of lifestyle changes on erectile dysfunction in obese men: a randomized controlled trial

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    Context: Healthy lifestyle factors are associated with maintenance of erectile function in men. Objective: To determine the effect of weight loss and increased physical activity on erectile and endothelial functions in obese men. Design, Setting, and Patients: Randomized, single-blind trial of 110 obese men (body mass index ≥30) aged 35 to 55 years, without diabetes, hypertension, or hyperlipidemia, who had erectile dysfunction that was determined by having a score of 21 or less on the International Index of Erectile Function (IIEF). The study was conducted from October 2000 to October 2003 at a university hospital in Italy. Interventions: The 55 men randomly assigned to the intervention group received detailed advice about how to achieve a loss of 10% or more in their total body weight by reducing caloric intake and increasing their level of physical activity. Men in the control group (n=55) were given general information about healthy food choices and exercise. Main Outcomes Measures: Erectile function score, levels of cholesterol and tryglycerides, circulating levels of interleukin 6, interleukin 8, and C-reactive protein, and endothelial function as assessed by vascular responses to L-arginine. Results: After 2 years, body mass index decreased more in the intervention group (from a mean [SD] of 36.9 [2.5] to 31.2 [2.1]) than in the control group (from 36.4 [2.3] to 35.7 [2.5]) (P<.001), as did serum concentrations of interleukin 6 (P=.03), and C-reactive protein (P=.02). The mean (SD) level of physical activity increased more in the intervention group (from 48 [10] to 195 [36] min/wk; P<.001) than in the control group (from 51 [9] to 84 [28] min/wk; P<.001). The mean (SD) IIEF score improved in the intervention group (from 13.9 [4.0] to 17 [5]; P<.001), but remained stable in the control group (from 13.5 [4.0] to 13.6 [4.1]; P=.89). Seventeen men in the intervention group and 3 in the control group (P=.001) reported an IIEF score of 22 or higher. In multivariate analyses, changes in body mass index (P=.02), physical activity (P=.02), and C-reactive protein (P=.03) were independently associated with changes in IIEF score. Conclusion: Lifestyle changes are associated with improvement in sexual function in about one third of obese men with erectile dysfunction at baseline

    Particle Physics from Almost Commutative Spacetimes

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    Our aim in this review article is to present the applications of Connes' noncommutative geometry to elementary particle physics. Whereas the existing literature is mostly focused on a mathematical audience, in this article we introduce the ideas and concepts from noncommutative geometry using physicists' terminology, gearing towards the predictions that can be derived from the noncommutative description. Focusing on a light package of noncommutative geometry (so-called 'almost commutative manifolds'), we shall introduce in steps: electrodynamics, the electroweak model, culminating in the full Standard Model. We hope that our approach helps in understanding the role noncommutative geometry could play in describing particle physics models, eventually unifying them with Einstein's (geometrical) theory of gravity.Comment: 104 pages, 5 figures, version 2 (minor changes and some additional references

    The MINOUWApp: a web-based tool in support of by-catch and discards management

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    Current fishing practices often do not allow adequate selection of species or sizes of fish, resulting in unwanted catches, subsequently discarded, with the consequent negative effects on both marine communities and fisheries profitability. The cross-analysis of density patches of potential unwanted catches and distribution of fishing effort can support the identification of spatial-temporal hot-spots in which the fishing pressure should be reduced to limit the amount of discards. The MinouwApp represents a technological and methodological framework to bring different, and structurally complex, sources of georeferenced data together into a simple visual interface aiming to interactively explore temporal ranges and areas of interest. The objective is to improve the understanding of fisheries dynamics, including discards, thus contributing to the implementation of discard management plans in a context of participative, ecosystem-based fisheries management strategies

    Immunodepletion in xenotransplantation

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    Xenograft transplantation is perhaps the most immunologically difficult problem in transplantation today. An overwhelming hyperacute rejection reaction (HAR) occurs within minutes of organ implantation. Preformed antibodies are thought to initiate this process. We used a pig-to-dog renal xenograft transplant model and investigated methods of decreasing the severity of hyperacute rejection. Female pigs weighing 15-20 kg were used as donors. Recipients were mongrel dogs weighing 15-25 kg. Experimental dogs were all given a number of treatments of IgG depletion using an antibody removal system (Dupont-Excorim). This machine immunoadsorbs plasma against a column containing immobilized staphylococcal protein A, which is known to bind the IgG Fc receptor. An 84% reduction in the IgG levels and a 71% reduction in IgM levels was achieved. Postoperative assessment was made of urine output, time to onset of HAR, and histopathological examination of the rejected kidneys. Although cross-matches between donor lymphocytes and recipient sera remained strongly positive in the treated dogs, there was a two- to fourfold reduction in the titers. The time to onset of HAR was prolonged in the experimental group, and the urine output was increased slightly. The histopathologic changes in the experimental group generally showed signs of HAR, but of less intensity than in the nonimmunodepleted control group. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted
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