Consistency of objective Bayes factors as the model dimension grows

In the class of normal regression models with a finite number of regressors, and for a wide class of prior distributions, a Bayesian model selection procedure based on the Bayes factor is consistent [Casella and Moreno J. Amer. Statist. Assoc. 104 (2009) 1261--1271]. However, in models where the number of parameters increases as the sample size increases, properties of the Bayes factor are not totally understood. Here we study consistency of the Bayes factors for nested normal linear models when the number of regressors increases with the sample size. We pay attention to two successful tools for model selection [Schwarz Ann. Statist. 6 (1978) 461--464] approximation to the Bayes factor, and the Bayes factor for intrinsic priors [Berger and Pericchi J. Amer. Statist. Assoc. 91 (1996) 109--122, Moreno, Bertolino and Racugno J. Amer. Statist. Assoc. 93 (1998) 1451--1460]. We find that the the Schwarz approximation and the Bayes factor for intrinsic priors are consistent when the rate of growth of the dimension of the bigger model is $O(n^b)$ for $b<1$. When $b=1$ the Schwarz approximation is always inconsistent under the alternative while the Bayes factor for intrinsic priors is consistent except for a small set of alternative models which is characterized.Comment: Published in at http://dx.doi.org/10.1214/09-AOS754 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Historiografía y revolución: la " nueva" oleada de historiadores cubanos

This article provides an overview of the work carried on by the recent generations of Cuban historians from the 1880s to the present. Apart from the helpful and instructive inventory of authors and works that this study provides, it also seeks to characterise the historical and institutional context that gave rise to the emergence of new trends in historiography. Additionally, this text assesses the positive features and deficiencies attributed to young researchers from the island.Este artículo ofrece un panorama de la labor desarrollada por las recientes promociones de historiadores cubanos, desde la década del ochenta del pasado siglo hasta la actualidad. Al margen del provechoso e instructivo inventario de autores y obras que este estudio ofrece, se pretende caracterizar el contexto histórico e institucional que diera lugar a la emergencia de nuevas tendencias historiográficas. Además, en este texto se evalúan los rasgos positivos y las deficiencias atribuibles a los jóvenes investigadores de la Isla

Universidades de tercera generación en Colombia

La integración de las universidades de corte tradicional a la moderna sociedad mediante la aplicación de programas académicos de formación de profesionales competentes, que incluyan en sus currículos espacios adecuados de interacción de los estudiantes con el sector productivo, propiciando el aprendizaje mediante la ejecución de proyectos de aplicación real e inmediata en alianza con la industria para impulsar el desarrollo técnico económico, primero regional y luego expandir su accionar con visión global, es una necesidad para dar pasos contundentes y sacar por fin al país del subdesarrollo

Consistency of Bayesian procedures for variable selection

It has long been known that for the comparison of pairwise nested models, a decision based on the Bayes factor produces a consistent model selector (in the frequentist sense). Here we go beyond the usual consistency for nested pairwise models, and show that for a wide class of prior distributions, including intrinsic priors, the corresponding Bayesian procedure for variable selection in normal regression is consistent in the entire class of normal linear models. We find that the asymptotics of the Bayes factors for intrinsic priors are equivalent to those of the Schwarz (BIC) criterion. Also, recall that the Jeffreys--Lindley paradox refers to the well-known fact that a point null hypothesis on the normal mean parameter is always accepted when the variance of the conjugate prior goes to infinity. This implies that some limiting forms of proper prior distributions are not necessarily suitable for testing problems. Intrinsic priors are limits of proper prior distributions, and for finite sample sizes they have been proved to behave extremely well for variable selection in regression; a consequence of our results is that for intrinsic priors Lindley's paradox does not arise.Comment: Published in at http://dx.doi.org/10.1214/08-AOS606 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

On the frequentist and Bayesian approaches to hypothesis testing

Hypothesis testing is a model selection problem for which the solution proposed by the two main statistical streams of thought, frequentists and Bayesians, substantially differ. One may think that this fact might be due to the prior chosen in the Bayesian analysis and that a convenient prior selection may reconcile both approaches. However, the Bayesian robustness viewpoint has shown that, in general, this is not so and hence a profound disagreement between both approaches exists. In this paper we briefly revise the basic aspects of hypothesis testing for both the frequentist and Bayesian procedures and discuss the variable selection problem in normal linear regression for which the discrepancies are more apparent. Illustrations on simulated and real data are given

Assessing regional convergence of the size of middle classes in Euro-Mediterranean countries

Historically, Euro-Mediterranean European countries have presented high levels of intra- and interregional socio-economic inequalities and are regular recipients of financial support under European Union Cohesion Policy. This paper provides evidence of regional convergence in the size of lower- and upper-middle-income classes across regions of France, Greece, Italy and Spain for the period 2004-17. Our results also reveal that changes in class size in neighbouring regions are associated with changes in the same direction in the lower- and upper-middle classes of the region of interest. As regards growth of class size in neighbouring regions, the convergence process is offset in both middle-income groups, but only partially for the upper-middle class. Furthermore, the economic cycle affects the process of regional convergence in the size of the middle class, although the effects are non-homogeneous for both middle-class groups. While increases or decreases in gross domestic product (GDP) do not seem to be closely related to upper-middle-class size, relatively persistent decreases rather than increases in GDP over time tend to be more linked to lower-middle-class size. These findings point to significant differences in the convergence dynamics between lower- and upper-middle classes, with the former being more sensitive to both neighbouring regions and the business cycle.University of MalagaUniversity of GranadaRegional Government of Andalusia [UMA18-FEDERJA-005]Spanish Ministry of Science and Innovation [AEI/10.13039/501100011033

Base de Datos de Investigación en Agricultura para el Desarrollo: Resultados preliminares

Comunicación presentada en el I Congreso Investigación en Agricultura para el Desarrollo, celebrado en Madrid el 17 y 18 de octubre de 2011.La investigación en agricultura para el desarrollo en España carece de un organismo o una estructura que coordine la información y la producción científica. El único informe previo donde se analizó la actividad en este ámbito fue el "Informe sobre la Cooperación Universitaria al Desarrollo en al Ámbito Agroalimentario - El caso español", realizado por las fundaciones Triptolemos y Cultura de Paz, correspondiente al año 2006-2007.Este trabajo está financiado por el proyecto AECID CAP10-0080 y la ayuda INIA AC2010-00037.Peer Reviewe

A pilot study of morphological changes in coated Nd-YAG lased enamel

Tipo de producción: Meeting Abstracts Tipo de soporte: Revista JCR Fuente de impacto: WOS (JCR) Categoría: DENTISTRY, ORAL SURGERY & MEDICINE Índice de impacto: 1,5 (5 años); Web of Science Core Collection: Science Citation Index Expanded.A pilot study of morphological changes in coated Nd-YAG lased enamel, Pediatric Dentistry, 1993. Vol. 15, núm. 2, p. 133. (ISSN / eISSN: 0164-1263 / 1942-5473). ABSTRACT: The objective of this pilot study was to 1) evaluate the enamel surface alteration microscopic pattems after laser and acid etching technique with scanning elechonic microscope, and 2) suggest the Nd-YAG laser power output necessary for effective enamel-bracket bonding procedure, by using different laser energy output as a qüantitative variable and two dye primers (black ink and black pencil) as qualitative variables. Four caries-free human premolars were extracted and stored in saline water. Teeth were debrided and cleaned and then sectioned, providing two samples each and mounted in acrylic to facilitate their handling. Enamel etching was performed using a Nd-YAG laser with pulsed energy type and variable power delivered by optic fiber. Every specimen underwent a different etching procedure. A scanning electron microscope was used at 10 KV and 30 grade. The results show that double laser exposition at 15 pps / .75 watts caused a fused enamel with melting and many pits of variable diameter, giving a drilted aspect to enamel. However, microfractures appear in all the dosages tested. Hence, more research should be made before using double-exposition at 15 pps/ .75 watts with black ink as primer to etch enamel with Nd-YAG laser.El objetivo de este estudio piloto fue 1) evaluar los patrones microscópicos de alteración de la superficie del esmalte después de la técnica de grabado con láser y ácido con un microscopio electrónico de barrido, y 2) sugerir la potencia de salida del láser Nd-YAG necesaria para un procedimiento eficaz de unión del esmalte al bracket, mediante el uso de diferentes salidas de energía láser como variable cuantitativa y dos imprimaciones capaces de absorber el LASER (tinta negra y lápiz negro) como variables cualitativas. Cuatro premolares humanos libres de caries se extrajeron y almacenaron en agua salina. Los dientes fueron desbridados, limpiados y luego seccionados, proporcionando dos muestras cada uno y se montaron en resina acrílica para facilitar su manipulación. El grabado del esmalte se realizó utilizando un láser Nd-YAG con energía de tipo pulsado y potencia variable a través de fibra óptica. Cada ejemplar se sometió a un procedimiento de grabado diferente. Se utilizó un microscopio electrónico de barrido a 10 KV y en ángulo de 30 grados sobre la superficie del esmalte. Los resultados muestran que la doble exposición al láser a 15 pps / 0,75 vatios provocó un esmalte fundido con derretimiento y muchos hoyos de diámetro variable, dando un aspecto perforado al esmalte. Sin embargo, aparecen microfracturas en todas las dosis probadas. Por lo tanto, se debe realizar más investigación antes de utilizar la doble exposición a 15 pps / 0,75 vatios con tinta negra como base para grabar el esmalte con láser Nd-YAG.Programa Postdoctoral en Odontopediatría. Escuela de Odontología, Universidad de Puerto Rico (Convenio para la formación de docentes entre la Universidad de Granada, la Universidad de Puerto Rico y la Consejería de Educación de la Junta de Andalucía)