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

The motivation duty. A requirement from the neo-constitutionalism for the application and creation of law

This article set out that in constitutional law tensions are present in the application and interpretation of rights included in the Constitution, and debate arise about the way courts and judges have try to solve those tensions. Summarizes a first jurisprudential approximation about the duty of motivation ofthe decisions –administrative and judiciaries– and its conceptualization, according to criteria given by the Colombian Constitutional Court.El presente artículo plantea que en el derecho constitucional se presentan tensiones en la aplicación e interpretación de derechos contenidos en la Constitución, y surgen debates sobre la forma como los tribunales y jueces han tratado de solucionar esas tensiones. Da cuenta de una primera aproximación jurisprudencial sobre el deber de motivación de las decisiones –administrativas y judiciales- y su conceptualización, según los criterios señalados por la Corte Constitucional colombiana

Disparities at the entrance door: gender gaps in elementary school

A sizable body of literature has concluded that males do better in math compared with females. Although differences have narrowed over time, generally speaking males do better on standardized test scores. However, there is no agreement on when such disparity appears and how big the differences are. This paper explores at what point during elementary school gender differences appear, when these become significant and how the gap evolves as children progress at early years. To explain differences by gender, math scores are used. Data comes from the Early Childhood Longitudinal Program (ECLS-K) in the USA. Longitudinal and cross-sectional analysis are conducted. Gender gaps are decomposed through the use of ñopo-match. Results show that gender gaps are almost inexistent at the beginning of schooling but they broaden rapidly. Between first and fifth grade, gender gaps increase by 60.8%. The unexplained components of gender differences increase over time, which suggests that the importance of socioeconomic and school factors decreases as children progress in the school.Um expressivo número de trabalhos tem concluído que estudantes do sexo masculino têm melhor rendimento em matemática em comparação com seus pares femininos. Embora as diferenças se tenham reduzido ao longo do tempo, meninos em geral têm melhor performance em testes padronizados. No entanto, não há consenso entre os pesquisadores/ as sobre quando estas disparidades aparecem e sobre a dimensão destas diferenças. Este artigo busca identificar quando as diferenças de gênero aparecem, quando elas se tornam significativas e como evoluem à medida que estudantes progridem nos primeiros anos da vida escolar. Para explicar as diferenças na performance escolar por gênero, este trabalho considera as pontuações nos testes de matemática entre estudantes da escola primária. São realizadas análises longitudinais e transversais com base nos dados do Programa Longitudinal da Primeira Infância (ECLS-K, na sigla em inglês) nos EUA. As disparidades de gênero são decompostas por meio do método ñopo-match. Os resultados mostram que enquanto as diferenças são quase inexistentes no início da escolaridade, elas se ampliam rapidamente entre o primeiro e o quinto ano, chegando a um acentuado índice de 60,8%. O aumento das disparidades no rendimento escolar de meninos e meninas ao longo do tempo por causas que não sejam os fatores socioeconômicos e escolares sugere que estes últimos diminuem à medida que as crianças progridem na escola

Coagulación intravascular diseminada: Una revisión de tema

Introduction: Disseminated intravascular coagulation is a secondary syndrome to underlying pathologies, where localized coagulation activation and generalized inflammatory response can lead to tissue and microvascular damage. A prevalence of 10.8% has been reported in several intensive care units in Colombia. Its presentation in the context of sepsis is different depending on the type of infection. Objective: To conduct a review of literature of the most outstanding concepts of disseminated intravascular coagulation. Materials and methods: A review was made by means of the search of original articles, systematic and narrative reviews, in the PubMed and ScienceDirect databases and in the Google Scholar search engine; 80 articles were selected, of which 51 were included. Publications were taken into account in Spanish, English and French, with a publication date of less than or equal to 5 years. Results: The description of treatment, etiology, clinical presentation and diagnosis of Disseminated Intravascular Coagulation was made, with special emphasis on the studies on molecular markers and new therapeutic alternatives. Conclusion: Disseminated intravascular coagulation is a complication which contributes to increase morbidity and mortality, whose early diagnosis and treatment contribute significantly to better clinical evolution

Quantitative approach for the risk assessment of African swine fever and Classical swine fever introduction into the United States through legal imports of pigs and swine products.

The US livestock safety strongly depends on its capacity to prevent the introduction of Transboundary Animal Diseases (TADs). Therefore, accurate and updated information on the location and origin of those potential TADs risks is essential, so preventive measures as market restrictions can be put on place. The objective of the present study was to evaluate the current risk of African swine fever (ASF) and Classical swine fever (CSF) introduction into the US through the legal importations of live pigs and swine products using a quantitative approach that could be later applied to other risks. Four quantitative stochastic risk assessment models were developed to estimate the monthly probabilities of ASF and CSF release into the US, and the exposure of susceptible populations (domestic and feral swine) to these introductions at state level. The results suggest a low annual probability of either ASF or CSF introduction into the US, by any of the analyzed pathways (5.5*10-3). Being the probability of introduction through legal imports of live pigs (1.8*10-3 for ASF, and 2.5*10-3 for CSF) higher than the risk of legally imported swine products (8.90*10-4 for ASF, and 1.56*10-3 for CSF). This could be caused due to the low probability of exposure associated with this type of commodity (products). The risk of feral pigs accessing to swine products discarded in landfills was slightly higher than the potential exposure of domestic pigs through swill feeding. The identification of the months at highest risk, the origin of the higher risk imports, and the location of the US states most vulnerable to those introductions (Iowa, Minnesota and Wisconsin for live swine and California, Florida and Texas for swine products), is valuable information that would help to design prevention, risk-mitigation and early-detection strategies that would help to minimize the catastrophic consequences of potential ASF/CSF introductions into the US

Construcción de sistemas de numeración. Propuesta para un aula inclusiva 

Los sistemas de numeración a lo largo de la historia han sido quizás los elementos más importantes en el desarrollo del saber matemático junto con la geometría; en esta propuesta para un aula inclusiva, se plantea un recorrido no solo desde la historia de la matemática, sino desde la didáctica en donde utilizando la teoría de situaciones didácticas de Brousseau se propone una secuencia que muestra en los estudiantes de grado sexto la evolución de los sistemas de numeración y el porqué de la escogencia del sistema posicional decimal que utilizamos. Estas actividades se diseñan utilizando recursos manipulativos tangibles en un aula inclusiva partiendo de una experiencia previa con estudiantes con limitación visual en el colegio OEA, donde se buscó acercar a los estudiantes a conceptos aditivos, multiplicativos, manejo de bases, posición y escritura polinomial

Successful leadership in disadvantaged context. The experience of a secondary school

El trabajo que se presenta está encuadrado bajo el proyecto llamado International Successful School Principalship Project (ISSPP). En el mismo participan 21 países entre ellos España. Mostramos por tanto, un estudio de caso ubicado en la provincia de Granada, siendo un centro caracterizado por encontrarse situado en un contexto de exclusión social y por tener un elevado rendimiento académico pese a sus limitaciones. El objetivo que perseguimos es el mismo que se marca en este proyecto: analizar los rasgos y, las estrategias que desarrollan los líderes escolares exitosos. Presentamos un estudio de caso de un centro de educación secundaria de Granada, considerado de riesgo social y de alto rendimiento académico. Para ellos se han realizado entrevistas al equipo directivo, profesorado, alumnado, padres y madres y representantes de la administración, además de hacer una revisión de documentos. Para el análisis de datos se ha utilizado en programa cualitativo NVIVO 10, siguiendo las directrices marcadas en el proyecto. Finalmente, los resultados obtenidos giran en conocer las características y el funcionamiento del centro así como las características del director y su estilo de liderazgoThe work presented is framed under the project called International Successful School Principalship Project (ISSPP). In the same participate 21 countries among them Spain. We show, therefore, a case study located in the province of Granada, being a center characterized by being located in a context of social exclusion and for having a high academic performance. The objective we pursue is the same that is marked in this project: analyze the traits and strategies developed by successful school leaders. We present a case study of a secondary education center in Granada, considered to be social risk and high academic performance. For them, interviews have been conducted with the management team, teachers, students, parents and representatives of the administration, as well as a review of documents. For the data analysis it has been used in qualitative program NVIVO 10, following the guidelines marked in the project. Finally the results obtained revolve around the characteristics and functioning of the center as well as the characteristics of the director and his style of leadershi

Profesional identity and succesful leadership in challenging contexts: A case study in the province of Granada

Actualmente, el liderazgo exitoso es una de las líneas investigadoras más potentes en el ámbito educativo a nivel internacional. De él, han aparecido otras líneas que han dedicado sus esfuerzos a conocer la identidad profesional del líder educativo eficaz. El proyecto ISSPP (International Successful School Principalship Project), por ejemplo, es una red que ha enfatizado mucho sobre esta cuestión, llevando a cabo numerosos estudios, cuya misión es el análisis integral de los directores como líderes escolares, en una multitud de países. Bajo un enfoque cualitativo, se ha hecho un estudio de caso sobre un centro, que podría ser catalogado como desafiante, de la provincia de Granada. Para ello, se confeccionaron unos guiones de entrevistas específicos, cuya finalidad era conocer la identidad profesional del director, ahondando en su trayectoria profesional previa, en los retos laborales que percibía y sus perspectivas de futuro. Durante el transcurso del mismo, tuvieron lugar tres entrevistas que abarcaron los tres grandes bloques ya mencionados. Entre los resultados hallados, destacamos que los directores a menudo se sienten solos, echando en falta el respaldo de la administración cuando tratan de promocionar iniciativas de cambio en los centros. Asimismo, reconocen ciertas carencias formativas a la hora de desempeñar su cargoNowadays, successful leadership is one of the most powerful research lines in the educational field at the international level. From it, other research lines have appeared and they have dedicated their efforts to know the proffesional identity of the effective educational leader. The ISSPP (International Successful School Principalship Project) project, for instance, is a network that has emphasized much on this issue, carrying out numerous studies whose mission is the comprehensive analysis of principals as school leaders in a multitude of countries. From a qualitative approach, a case study has been made of a center, which could be classified as challenging, in the province of Granada. To do this, a series of specific interview scripts were created, whose purpose was to know the professional identity of the School principal, delving into his previous professional career, the work challenges he perceived and his future prospects. During the course of the same, three interviews took place that covered the three large blocks already mentioned. Among the results found, we emphasize that principals often feel lonely, missing the support of the administration when they try to promote initiatives of change in the centers. They also recognize certain formative shortcomings in the performance of their dutie

Ending the Financial Entrapment of Street Vendors in Colombia

In the global South, the informal economy provides over 50 per cent of urban employment. In Cali, Colombia, the absence of government intervention and financial programmes means that illegal moneylenders are used by workers in the informal economy to keep themselves afloat. Consequently, workers such as street vendors remain beholden to extortionate interest rates. Based on research by POLIS (Observatory of Public Policy) of Universidad ICESI and Cardiff University, the Mayor of Cali has incorporated a financial policy which aims to enable street vendors to borrow money quickly and reasonably, protecting them from turning to the gota-gota moneylenders and empowering them to build a sustainable livelihood.ESRC-DFI

The leadership for school improvement and social justice. A case study in secondary education school

Esta investigación es un estudio de caso de un centro de Educación Secundaria Obligatoria, se persigue el mismo objetivo que el proyecto del que forma parte, que es: conocer las prácticas exitosas de liderazgo para la mejora de los resultados académicos. Se ha utilizado el estudio de caso como metodología y la entrevista y la revisión de documentos como instrumentos de investigación. Los resultados obtenidos resaltan las características y estrategias exitosas de liderazgo para conseguir buenos resultados académicos aun siendo un centro con unas características no demasiado favorecedoras. Los resultados indican que el director desarrolla un liderazgo distribuido y participativo, subrayando las características relacionadas con su carácter, formación, capacidad de mejora, de conseguir desarrollar un ambiente favorable hacia el trabajo tanto para el alumnado como el profesorado, el compartir una visión clara y para ello trabajar de un modo conjunto con la comunidad educativa (alumnado, profesorado, familias, etc.). Las conclusiones obtenidas están relacionadas con los resultados del proyecto ISSPP, relativas a: la personalización de la experiencia de aprendizaje, el trabajo colaborativo de los docentes, la retroalimentación de la comunidad educativa para la mejora de la escuela, entre otrasThis research is a case study of a compulsory secondary education center, the same objective is pursued as the project of which it is part that is: to know the successful practices of leadership for the improvement of academic results. The case study has been used as a methodology and the interview and the review of documents as research instruments. The results obtained are focused on highlighting the characteristics and successful leadership strategies to achieve good academic results. The results indicate that the director develops a distributed and participative leadership, underlining the characteristics related to his character, training, capacity for improvement, of developing a favorable environment towards work both for students and teachers, to share a clear vision and to do this, work in a joint way with the educational community (students, teachers, families, etc.). The conclusions obtained are related to the results of the ISSPP project, related to: the personalization of the learning experience, the collaborative work of the teachers, the feedback of the educational community for the improvement of the school, among other