179 research outputs found

    Electric-Field Gradient at Cd Impurities in In2o3. A FLAPW Study

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    We report an ab initio study of the electric-field gradient tensor (EFG) at Cd impurities located at both inequivalent cationic sites in the semiconductor In2O3. Calculations were performed with the FLAPW method, that allows us to treat the electronic structure of the doped system and the atomic relaxations introduced by the impurities in the host lattice in a fully self-consistent way. From our results for the EFG (in excellent agreement with the experiments), it is clear that the problem of the EFG at impurities in In2O3 cannot be described by the point-charge model and antishielding factors.Comment: 4 pages, 2 figures, and 2 table

    El campo de las y los defensores de derechos humanos en México La estructura de posiciones en el campo

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    Segundo momento del análisis del campo de las y los defensores de derechos humanos en México en el que se hace una descripción muy general de las posiciones que ocupan los agentes más relevantes en materia de derechos humanos, o para violentarlos de manera estructural y sistemática o, por el contrario, para defenderlos y protegerlos.ITESO, A.C

    Impacto de la condición corporal sobre la fertilidad en vacas de la provincia de Pastaza- Ecuador

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    El objetivo fue evaluar el efecto de la condición corporal sobre la fertilidad en vacas de la provincia de Pastaza-Ecuador. Se utilizaron 2434 registros reproductivos de la base de datos entre el 2009- Las variables analizadas fueron: estado reproductivo gestante y no gestante, año, raza, condición corporal (CC), celo, toro o pajuela utilizada, técnico inseminador. La muestra para el análisis estadístico de los datos se basó en tres modelos de ANOVA y un modelo mixto. El porcentaje de preñez a nivel provincial logrado con este programa de mejoramiento fue del 60 al 69%. La CC solo fue significativa para la raza Charolais mestiza, quien mostró un coeficiente de correlación lineal bajo negativo con respecto a la gestación, las otras variables celo, pajuela, técnico tampoco tuvieron diferencias estadísticas (P>0.05). Pero en el análisis del segundo modelo aplicado se encontró diferencias significativas entre el lugar (cantón) y CC (P=0.047) y entre la raza de la vaca y raza del toro (P=0.006). Se concluye que la (CC) influyó sobre la gestación dependiendo del lugar, independiente de la raza de la vaca, factor que no resultó importante en la variable reproductiva estudiada, los factores ambientales: año, cantón y CC, influyen en los niveles de gestación de la población estudiada, de los factores genéticos analizados las razas de la vaca y del padre no influyeron, solamente el factor toro fue importante en la gestación de la vaca y el factor humano resultó determinante como causa de variación en la gestación

    Modeling, Simulation and Control of Pedestrian Avoidance Maneuver for an Urban Electric Vehicle

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    In this paper, the mathematical model of an electric vehicle, as well as the control system for avoiding pedestrians in urban traffic is described. The vehicle is modeled as a continuous system consisting of several subsystems. The discrete model of several sensors and actuators, a decision system, and low-level controllers for acceleration/braking and steering systems are added. Based on this model, a pedestrian avoidance maneuver for typical speeds in city traffic is simulated. When the sensory system detects a pedestrian in the vehicle’s path, the decision system calculates its trajectory. Using this information, the speed and/or direction that the vehicle must take in order to avoid the accident are estimated. These values are sent to the low-level controllers of the accelerator/brake and steering, which generate the signals to be applied to such systems to achieve the desired trajectory and speed

    The Degree and regularity of vanishing ideals of algebraic toric sets over finite fields

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    Let X* be a subset of an affine space A^s, over a finite field K, which is parameterized by the edges of a clutter. Let X and Y be the images of X* under the maps x --> [x] and x --> [(x,1)] respectively, where [x] and [(x,1)] are points in the projective spaces P^{s-1} and P^s respectively. For certain clutters and for connected graphs, we were able to relate the algebraic invariants and properties of the vanishing ideals I(X) and I(Y). In a number of interesting cases, we compute its degree and regularity. For Hamiltonian bipartite graphs, we show the Eisenbud-Goto regularity conjecture. We give optimal bounds for the regularity when the graph is bipartite. It is shown that X* is an affine torus if and only if I(Y) is a complete intersection. We present some applications to coding theory and show some bounds for the minimum distance of parameterized linear codes for connected bipartite graphs

    Large-scale multitrait genome-wide association analyses identify hundreds of glaucoma risk loci

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    Glaucoma, a leading cause of irreversible blindness, is a highly heritable human disease. Previous genome-wide association studies have identified over 100 loci for the most common form, primary open-angle glaucoma. Two key glaucoma-associated traits also show high heritability: intraocular pressure and optic nerve head excavation damage quantified as the vertical cup-to-disc ratio. Here, since much of glaucoma heritability remains unexplained, we conducted a large-scale multitrait genome-wide association study in participants of European ancestry combining primary open-angle glaucoma and its two associated traits (total sample size over 600,000) to substantially improve genetic discovery power (263 loci). We further increased our power by then employing a multiancestry approach, which increased the number of independent risk loci to 312, with the vast majority replicating in a large independent cohort from 23andMe, Inc. (total sample size over 2.8 million; 296 loci replicated at P < 0.05, 240 after Bonferroni correction). Leveraging multiomics datasets, we identified many potential druggable genes, including neuro-protection targets likely to act via the optic nerve, a key advance for glaucoma because all existing drugs only target intraocular pressure. We further used Mendelian randomization and genetic correlation-based approaches to identify novel links to other complex traits, including immune-related diseases such as multiple sclerosis and systemic lupus erythematosus

    ENIGMA MDD: seven years of global neuroimaging studies of major depression through worldwide data sharing

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    A key objective in the field of translational psychiatry over the past few decades has been to identify the brain correlates of major depressive disorder (MDD). Identifying measurable indicators of brain processes associated with MDD could facilitate the detection of individuals at risk, and the development of novel treatments, the monitoring of treatment effects, and predicting who might benefit most from treatments that target specific brain mechanisms. However, despite intensive neuroimaging research towards this effort, underpowered studies and a lack of reproducible findings have hindered progress. Here, we discuss the work of the ENIGMA Major Depressive Disorder (MDD) Consortium, which was established to address issues of poor replication, unreliable results, and overestimation of effect sizes in previous studies. The ENIGMA MDD Consortium currently includes data from 45 MDD study cohorts from 14 countries across six continents. The primary aim of ENIGMA MDD is to identify structural and functional brain alterations associated with MDD that can be reliably detected and replicated across cohorts worldwide. A secondary goal is to investigate how demographic, genetic, clinical, psychological, and environmental factors affect these associations. In this review, we summarize findings of the ENIGMA MDD disease working group to date and discuss future directions. We also highlight the challenges and benefits of large-scale data sharing for mental health research

    Monovision-based vehicle detection, distance and relative speed measurement in urban traffic

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    This study presents a monovision-based system for on-road vehicle detection and computation of distance and relative speed in urban traffic. Many works have dealt with monovision vehicle detection, but only a few of them provide the distance to the vehicle which is essential for the control of an intelligent transportation system. The system proposed integrates a single camera reducing the monetary cost of stereovision and RADAR-based technologies. The algorithm is divided in three major stages. For vehicle detection, the authors use a combination of two features: the shadow underneath the vehicle and horizontal edges. They propose a new method for shadow thresholding based on the grey-scale histogram assessment of a region of interest on the road. In the second and third stages, the vehicle hypothesis verification and the distance are obtained by means of its number plate whose dimensions and shape are standardised in each country. The analysis of consecutive frames is employed to calculate the relative speed of the vehicle detected. Experimental results showed excellent performance in both vehicle and number plate detections and in the distance measurement, in terms of accuracy and robustness in complex traffic scenarios and under different lighting conditions

    Multi-ancestry genome-wide association study of major depression aids locus discovery, fine mapping, gene prioritization and causal inference

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    Most genome-wide association studies (GWAS) of major depression (MD) have been conducted in samples of European ancestry. Here we report a multi-ancestry GWAS of MD, adding data from 21 cohorts with 88,316 MD cases and 902,757 controls to previously reported data. This analysis used a range of measures to define MD and included samples of African (36% of effective sample size), East Asian (26%) and South Asian (6%) ancestry and Hispanic/Latin American participants (32%). The multi-ancestry GWAS identified 53 significantly associated novel loci. For loci from GWAS in European ancestry samples, fewer than expected were transferable to other ancestry groups. Fine mapping benefited from additional sample diversity. A transcriptome-wide association study identified 205 significantly associated novel genes. These findings suggest that, for MD, increasing ancestral and global diversity in genetic studies may be particularly important to ensure discovery of core genes and inform about transferability of findings
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