A Comparative Review of Dimension Reduction Methods in Approximate Bayesian Computation

Approximate Bayesian computation (ABC) methods make use of comparisons between simulated and observed summary statistics to overcome the problem of computationally intractable likelihood functions. As the practical implementation of ABC requires computations based on vectors of summary statistics, rather than full data sets, a central question is how to derive low-dimensional summary statistics from the observed data with minimal loss of information. In this article we provide a comprehensive review and comparison of the performance of the principal methods of dimension reduction proposed in the ABC literature. The methods are split into three nonmutually exclusive classes consisting of best subset selection methods, projection techniques and regularization. In addition, we introduce two new methods of dimension reduction. The first is a best subset selection method based on Akaike and Bayesian information criteria, and the second uses ridge regression as a regularization procedure. We illustrate the performance of these dimension reduction techniques through the analysis of three challenging models and data sets.Comment: Published in at http://dx.doi.org/10.1214/12-STS406 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

FELINE ATRIAL NATRIURETIC PEPTIDE (ANP) HAS A SINGLE COPY GENE

O peptídeo natriurético atrial felino (PNA) é um hormônio sintetizado pelo miocárdio cardíaco atrial que, uma vez liberado na circulação, produz diurese, natriurese e vasodilatação periférica. Nós recentemente isolamos, sequenciamos e estabelemos a expressão cardíaca normal do PNA felino. No presente estudo, nós apresentamos o número de cópias gênicas do PNA em gatos. Foram extraídas amostras de DNA genômico do sangue periférico humano e felino, as quais foram purificadas e digeridas com as enzimas de restrição EcoRI, BamHI e HindIII, com posterior realização da técnica de Southern Blots. Primers para PCR, confeccionados para regiões de alta conservatividade entre espécies, foram utilizados para amplificação, clonagem e sequenciamento de um produto de 900 pares de bases, posteriormente utilizado como sonda de DNA. O gene do PNA felino possui uma única cópia gênica, a exemplo do PNA humano. Devido a sua similaridade, sondas de DNA felino puderam ser utilizadas para a hibridização de DNA genômico tanto do gato como do homem. Abstract Atrial natriuretic peptide (ANP) is a hormone normally synthesized by the cardiac atrial myocardium that once released, produces diuresis, natriuresis and peripheral vasodilation. We have recently isolated, sequenced and assessed the normal cardiac expression of feline ANP. In this study, we report on the number of copies of the feline ANP gene, which could have an effect on future molecular biology studies of ANP gene expression in cat models of cardiovascular disease. Cat and human genomic DNA (gDNA) were extracted for Southern blotting from blood. The purified DNA was digested with the restriction enzymes EcoRI, BamHI and HindIII followed by agarose gel electrophoresis and blotting onto nytran membranes. A feline ANP cDNA probe of approximately 900 base pairs was used for hybridization of the membranes. The results of Southern blotting showed that both the feline and human genomes contain a single copy of the ANP gene

Management of incidentally detected heart murmurs in dogs and cats

A dog or a cat has an incidentally detected heart murmur if the murmur is an unexpected discovery during a veterinary consultation that was not initially focused on the cardiovascular system. This document presents approaches for managing dogs and cats that have incidentally-detected heart murmurs, with an emphasis on murmur characteristics, signalment profiling, and multifactorial decision-making to choose an optimal course for a given patient