3,048 research outputs found

    Non-Gaussian dynamic Bayesian modelling for panel data

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    A first order autoregressive non-Gaussian model for analysing panel data is proposed. The main feature is that the model is able to accommodate fat tails and also skewness, thus allowing for outliers and asymmetries. The modelling approach is to gain sufficient flexibility, without sacrificing interpretability and computational ease. The model incorporates individual effects and we pay specific attention to the elicitation of the prior. As the prior structure chosen is not proper, we derive conditions for the existence of the posterior. By considering a model with individual dynamic parameters we are also able to formally test whether the dynamic behaviour is common to all units in the panel. The methodology is illustrated with two applications involving earnings data and one on growth of countries.autoregressive modelling; growth convergence; individual effects; labour earnings; prior elicitation; posterior existence; skewed distributions

    Model-based Clustering of non-Gaussian Panel Data

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    In this paper we propose a model-based method to cluster units within a panel. The underlying model is autoregressive and non-Gaussian, allowing for both skewness and fat tails, and the units are clustered according to their dynamic behaviour and equilibrium level. Inference is addressed from a Bayesian perspective and model comparison is conducted using the formal tool of Bayes factors. Particular attention is paid to prior elicitation and posterior propriety. We suggest priors that require little subjective input from the user and possess hierarchical structures that enhance the robustness of the inference. Two examples illustrate the methodology: one analyses economic growth of OECD countries and the second one investigates employment growth of Spanish manufacturing firmsautoregressive modelling; employment growth; GDP growth convergence; hierarchical prior; model comparison; posterior propriety; skewness

    Radiative corrections to the three-body region of the Dalitz plot of baryon semileptonic decays with angular correlation between polarized emitted baryons and charged leptons: The initial-baryon rest frame case

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    We complement the results for the radiative corrections to the s2.l angular correlation of baryon semileptonic decays of Ref. [1] with the final results in the rest frame of the decaying baryon.Comment: 7 pages, Revtex4, no figure

    Renormalization Group Equations for the CKM matrix

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    We derive the one loop renormalization group equations for the Cabibbo-Kobayashi-Maskawa matrix for the Standard Model, its two Higgs extension and the minimal supersymmetric extension in a novel way. The derived equations depend only on a subset of the model parameters of the renormalization group equations for the quark Yukawa couplings so the CKM matrix evolution cannot fully test the renormalization group evolution of the quark Yukawa couplings. From the derived equations we obtain the invariant of the renormalization group evolution for three models which is the angle α\alpha of the unitarity triangle. For the special case of the Standard Model and its extensions with v1v2v_{1}\approx v_{2} we demonstrate that also the shape of the unitarity triangle and the Buras-Wolfenstein parameters ρˉ=(11/2λ2)ρ\bar{\rho}=(1-{1/2}\lambda^{2})\rho and ηˉ=(11/2λ2)η\bar{\eta}=(1-{1/2}\lambda^{2})\eta are conserved. The invariance of the angles of the unitarity triangle means that it is not possible to find a model in which the CKM matrix might have a simple, special form at asymptotic energies.Comment: 9 page

    Determination of Carrier Diffusion Length Using Transient Electron Photoemission Microscopy in the GaAs/InSe Heterojunction

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    Carrier diffusion length and lifetime parameters for electron transport at nanoscale semiconductor slabs have been fitted using a 1D model and the decay data extracted from transient photoemission electron microscopy. Meanwhile, a conventional photoluminescence quenching measurement needs two separate samples with an active material between blocking and quenching layers to characterize the carrier transport properties. In this work, only one few-layer monocrystalline sample of gamma-InSe containing different thicknesses of active material is used to obtain a common diffusion coefficient consistent with previously reported values for vertical carrier diffusion in layered InSe

    Límites y alcances de la interpretación constitucional de la Suplencia de la Queja en Amparo Penal y los Derechos Humanos a partir de la Reforma Constitucional y Legal de 2011

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    El Juicio de Amparo en México con motivo de la reforma constitucional de 2011 y legal se ha transformado sustancialmente, principalmente su procedencia, ya que actualmente se ejerce contra normas generales, actos y omisiones de autoridad y excepcionalmente contra particulares que violen los derechos humanos consagrados en la Constitución y en los Tratados Internacionales en el que el Estado mexicano se aparte, procedimiento que es regulado por el sistema de Control Constitucional y Convencional; se puede tramitar por dos vías, la primera de manera indirecta ante Jueces de Distrito en competencia ordinaria, concurrente y auxiliar y ante los tribunales Unitarios de Circuito, y la segunda de manera directa ante los Tribunales Colegiados de Circuito, procedimientos en los que se deben observar una serie de principios sobre los cuales se regula su substanciación, algunos han subsistido en lo general, pero otros se han transformado, lo que ha impactado en sus excepciones, como es la denominada Suplencia de la Queja, sobre todo en materia penal, puesto que éste no será aplicado de manera total e indiscriminadamente, puesto que tiene alcances y límites, los que serán analizados para conocer su aplicabilidad y eficacia

    Using an external exposome framework to examine pregnancy-related morbidities and mortalities: Implications for health disparities research

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    © 2015 by the authors; licensee MDPI, Basel, Switzerland. Objective: We have conducted a study to assess the role of environment on the burden of maternal morbidities and mortalities among women using an external exposome approach for the purpose of developing targeted public health interventions to decrease disparities. Methods: We identified counties in the 48 contiguous USA where observed low birthweight (LBW) rates were higher than expected during a five-year study period. The identification was conducted using a retrospective space-time analysis scan for statistically significant clusters with high or low rates by a Discrete Poisson Model. Results: We observed statistically significant associations of LBW rate with a set of predictive variables. However, in one of the two spatiotemporal models we discovered LBW to be associated with five predictive variables (teen birth rate, adult obesity, uninsured adults, physically unhealthy days, and percent of adults who smoke) in two counties situated in Alabama after adjusting for location changes. Counties with higher than expected LBW rates were similarly associated with two environmental variables (ozone and fine particulate matter). Conclusions: The county-level predictive measures of LBW offer new insights into spatiotemporal patterns relative to key contributory factors. An external framework provides a promising place-based approach for identifying “hotspots” with implications for designing targeted interventions and control measures to reduce and eliminate health disparities

    Spin-Orbit Coupling and Ion Displacements in Multiferroic TbMnO3

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    The electronic and magnetic properties of TbMnO3 leading to its ferroelectric (FE) polarization were investigated on the basis of relativistic density functional theory (DFT) calculations. In agreement with experiment, we show that the spin-spiral plane of TbMnO3 can be either the bc- or ab-plane, but not the ac-plane. As for the mechanism of FE polarization, our work reveals that the "pure electronic" model by Katsura, Nagaosa and Balatsky (KNB) is inadequate in predicting the absolute direction of FE polarization. For the ab-plane spin-spiral state of TbMnO3, the direction of FE polarization predicted by the KNB model is opposite to that predicted by DFT calculations. In determining the magnitude and the absolute direction of FE polarization in spin-spiral states, it is found crucial to consider the displacements of the ions from their ecntrosymmetric positions
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