Bayesian inference for the multivariate skew-normal model: a Population Monte Carlo approach

Frequentist and likelihood methods of inference based on the multivariate skew-normal model encounter several technical difficulties with this model. In spite of the popularity of this class of densities, there are no broadly satisfactory solutions for estimation and testing problems. A general population Monte Carlo algorithm is proposed which: 1) exploits the latent structure stochastic representation of skew-normal random variables to provide a full Bayesian analysis of the model and 2) accounts for the presence of constraints in the parameter space. The proposed approach can be defined as weakly informative, since the prior distribution approximates the actual reference prior for the shape parameter vector. Results are compared with the existing classical solutions and the practical implementation of the algorithm is illustrated via a simulation study and a real data example. A generalization to the matrix variate regression model with skew-normal error is also presented

Objective Bayesian analysis for the multivariate skew-t model

We perform a Bayesian analysis of the p-variate skew-t model, providing a new parameterization, a set of non-informative priors and a sampler specifically designed to explore the posterior density of the model parameters. Extensions, such as the multivariate regression model with skewed errors and the stochastic frontiers model, are easily accommodated. A novelty introduced in the paper is given by the extension of the bivariate skew-normal model given in Liseo & Parisi (2013) to a more realistic p-variate skew-t model. We also introduce the R package mvst, which allows to estimate the multivariate skew-t model

Politicians “on board”! Do political connections affect banking activities in Italy?

This paper analyzes the effects of political presence in the boards of directors of cooperative banks. We refer our analysis to all politicians (almost 160.000) belonging to a political body in Italy. Overall, our dataset contains 1.858 board members referring to 127 cooperative banks. Results show that politically connected banks, in which politicians have executive roles in the board of directors, display higher net interest revenues, lower quality of the loans portfolio and lower efficiency relative to a control group of non-connected counterparts. Therefore, in the current debate on the reform of the statutes of the Italian cooperative banks, we argue that the problem is not for politicians to be in the boards but for them to hold executive positions.Cooperative Banks, Politics, Corporate Governance

Pain perception and migraine

Background: It is well-known that both inter-and intra-individual differences exist in the perception of pain; this is especially true in migraine, an elusive pain disorder of the head. Although electrophysiology and neuroimaging techniques have greatly contributed to a better understanding of the mechanisms involved in migraine during recent decades, the exact characteristics of pain threshold and pain intensity perception remain to be determined, and continue to be a matter of debate.Objective: The aim of this review is to provide a comprehensive overview of clinical, electrophysiological, and functional neuroimaging studies investigating changes during various phases of the so-called "migraine cycle" and in different migraine phenotypes, using pain threshold and pain intensity perception assessments.Methods: A systematic search for qualitative studies was conducted using search terms "migraine," "pain," "headache," "temporal summation," "quantitative sensory testing," and "threshold," alone and in combination (subject headings and keywords). The literature search was updated using the additional keywords "pain intensity," and "neuroimaging"to identify full-text papers written in English and published in peer-reviewed journals, using PubMed and Google Scholar databases. In addition, we manually searched the reference lists of all research articles and review articles.Conclusion: Consistent data indicate that pain threshold is lower during the ictal phase than during the interictal phase of migraine or healthy controls in response to pressure, cold and heat stimuli. There is evidence for preictal sub-allodynia, whereas interictal results are conflicting due to either reduced or no observed difference in pain threshold. On the other hand, despite methodological limitations, converging observations support the concept that migraine attacks may be characterized by an increased pain intensity perception, which normalizes between episodes. Nevertheless, future studies are required to longitudinally evaluate a large group of patients before and after pharmacological and non-pharmacological interventions to investigate phases of the migraine cycle, clinical parameters of disease severity and chronic medication usage

Desempeno y gestion de la Banca Chilena Periodo : 1997-2000

87 p.La presente investigación realiza un análisis comparativo de la gestión de la banca Chilena en relación a la banca Española y Estadounidenses con el objetivo de evaluar su desempeño financiero durante el periodo comprendido entre los anos 1997 a12000. Esta tesis se divide en cinco secciones, la primera sección se refiere a la revisión bibliográfica en la que se presentaran las herramientas y conceptos claves que ayudaran a llevar adelante la investigación. La segunda sección corresponde a la elaboración y descripción de la metodología que se empleara en el análisis de la información recopilada. La tercera sección presenta el análisis y los resultados de la investigación, y para esto, primero se caracteriza la situación circundante a la banca Chilena durante los anos 1974- 2000 y también se realizara un análisis financiero comparando a los bancos Chilenos con un benchmark donde se utilizan los principales bancos Españoles y Estadounidenses como referencia, la cuarta sección hace mención a las Fusiones y la Concentración bancaria durante el periodo 1997-2000. Por ultimo se realiza un análisis de como Internet es reconocida por los bancos

Novel strategies of adoptive immunotherapy: How natural killer cells may change the treatment of elderly patients with acute myeloblastic leukemia

Although many attempts have been made to identify novel molecular-targeted therapies for patients with acute myeloid leukemia, their translation into the clinic have had limited impact. In particular, the question of effective and curative treatments for elderly patients, who are not eligible for stem cell transplantation, remains an unmet medical need. To answer this question, a wide range of immunologic therapeutic strategies, mostly T cell based, have been proposed and investigated. At present, however, the clinical results have been largely unsatisfactory. Natural killer cells have recently been used as a means of adoptive immunotherapy with promising clinical results. On the basis of recent clinical reports and moving from the basic immunobiology of natural killer cells, here we discuss some open issues in the clinical translation of natural killer-based adoptive immunotherapy for the management of elderly patients with acute myeloid leukemia

Biological compatibility between two temperate lineages of brown dog ticks, Rhipicephalus sanguineus (sensu lato)

Background: The brown dog tick Rhipicephalus sanguineus (sensu stricto) is reputed to be the most widespread tick of domestic dogs worldwide and has also been implicated in the transmission of many pathogens to dogs and humans. For more than two centuries, Rh. sanguineus (s.s.) was regarded as a single taxon, even considering its poor original description and the inexistence of a type specimen. However, genetic and crossbreeding experiments have indicated the existence of at least two distinct taxa within this name: the so-called "temperate" and "tropical" lineages of Rh. sanguineus (sensu lato). Recent genetic studies have also demonstrated the existence of additional lineages of Rh. sanguineus (s.l.) in Europe and Asia. Herein, we assessed the biological compatibility between two lineages of Rh. sanguineus (s.l.) found in southern Europe, namely Rhipicephalus sp. I (from Italy) and Rhipicephalus sp. II (from Portugal). Methods: Ticks morphologically identified as Rh. sanguineus (s.l.) were collected in southern Portugal and southern Italy. Tick colonies were established and crossbreeding experiments conducted. Morphological, biological and genetic analyses were conducted. Results: Crossbreeding experiments confirmed that ticks from the two studied lineages were able to mate and generate fertile hybrids. Hybrid adult ticks always presented the same genotype of the mother, confirming maternal inheritance of mtDNA. However, larvae and nymphs originated from Rhipicephalus sp. I females presented mtDNA genotype of either Rhipicephalus sp. I or Rhipicephalus sp. II, suggesting the occurrence of paternal inheritance or mitochondrial heteroplasmy. While biologically compatible, these lineages are distinct genetically and phenotypically. Conclusions: The temperate lineages of Rh. sanguineus (s.l.) studied herein are biologically compatible and genetic data obtained from both pure and hybrid lines indicate the occurrence of paternal inheritance or mitochondrial heteroplasmy. This study opens new research avenues and raises question regarding the usefulness of genetic data and crossbreeding experiments as criteria for the definition of cryptic species in ticks

Dolphin Morbillivirus in Eurasian Otters, Italy

We report biomolecular evidence of dolphin morbillivirus in 4 wild Eurasian otters (Lutra lutra) from southern Italy; 2 animals showed simultaneous immunohistochemical reactivity against morbilliviral antigen. These cases add further concern and support to the progressively expanding host range of dolphin morbillivirus in the western Mediterranean Sea

Estudios biológicos in vitro de materiales utilizados en osteosíntesis

Contexto: diferentes materiales son utilizados para fabricar prótesis empleadas en medicina reparadora siendo el titanio, por sus características químicas, el más frecuentemente empleado. Propósito: en el presente trabajo se evalúa la biocompatibilidad de diferentes muestras de prótesis médicas fabricadas por la Empresa FICO S.A. Métodos: mediante técnicas de citotoxicidad y genotoxicidad se estudió su potencial capacidad de integrarse a los tejidos, empleándose en los bioensayos cultivos celulares de las líneas UMR-106 y L929. Por medio de las técnicas de rojo neutro, colorimétrico de MTT, contacto directo, difusión en agar y producción de colágeno se estudiaron los niveles de citotoxicidad. Además, a través de la técnica de naranja de acridina se determinó la viabilidad celular. El “ensayo cometa” se empleó para determinar la genotoxicidad. Resultados: los resultados de los bioensayos empleados mostraron una alta biocompatibilidad, y no se evidenciaron diferencias significativas con los controles negativos. Conclusión: las técnicas empleadas en el presente trabajo pueden constituirse en herramientas para el análisis de materiales de uso biomédico.Context: some materials are used to factory medical prosthesis, in repairing medicine. Titanium is the most common used material bi their chemical characteristics. Aim: to evaluate biocompatibility in different samples of medical prosthesis, manufactured by FICO S.A. enterprise.Methods: through cytotoxicity and genotoxicity techniques, it analyzed the potential capability to integrate into the tissues, working with cell cultures and cell lines UMR-106 y L929. Also it used techniques such as, neutro red, colorimetric of MTT, direct contact, diffusion on agar and collagen production, it evaluated the cytotoxicity levels. Also with acridine orange technique it sets cell viability. Comet essay was used to establish genotocicity. Results: the study shows high biocompatibility, and it does not found significant difference in negative controls. Conclusion: It recommends these techniques to evaluate biomedical prosthesis.Fil: Castrogiovanni, Daniel Cayetano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Parisi, Julieta Marcia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Reigosa, Miguel Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin