A Bayesian shared component model for genetic association studies

We present a novel approach to address genome association studies between single nucleotide polymorphisms (SNPs) and disease. We propose a Bayesian shared component model to tease out the genotype information that is common to cases and controls from the one that is specific to cases only. This allows to detect the SNPs that show the strongest association with the disease. The model can be applied to case-control studies with more than one disease. In fact, we illustrate the use of this model with a dataset of 23,418 SNPs from a case-control study by The Welcome Trust Case Control Consortium (2007) with 2,000 patients with diabetes type 1, 2,000 with diabetes type 2 and a control group with 3,000 individuals. We carry out a simulation study to assess the sensitivity and specificity of our model to detect SNPs with excess risk. Our results show that the method we propose here can be a very useful tool for this type of studies. The model has been implemented in the bayesGen library of the R statistical package

About the linearity of the color-magnitude relation of early-type galaxies in the Virgo cluster

We revisit the color-magnitude relation (CMR) of the Virgo cluster early-type galaxies in order to explore its alleged non-linearity. To this aim, we reanalyze the relation already published from data obtained within the ACS Virgo Cluster Survey of the Hubble Space Telescope, and perform our own photometry and analysis of the images of the 100 early-type galaxies observed as part of this survey. In addition, we compare our results with those reported in the literature from data of the Sloan Digital Sky Survey. We have found that when the brightest galaxies and untypical systems are excluded from the sample, a linear relation arises in agreement with what is observed in other groups and clusters. The central regions of the brightest galaxies also follow this relation. In addition, we notice that Virgo contains at least four compact elliptical galaxies besides the well known object VCC 1297 (NGC 4486B). Their locations in the -luminosity diagram define a different trend to that followed by normal early-type dwarf galaxies, setting an upper limit in effective surface brightness and a lower limit in effective radius for their luminosities. Based on the distribution of different galaxy sub-samples in the color-magnitude and -luminosity diagrams we draw some conclusions on their formation and the history of their evolution.Comment: 21 pages, 4 figures, 2 tables. Accepted for publication in Ap

frailtypack: An R Package for the Analysis of Correlated Survival Data with Frailty Models Using Penalized Likelihood Estimation or Parametrical Estimation

Frailty models are very useful for analysing correlated survival data, when observations are clustered into groups or for recurrent events. The aim of this article is to present the new version of an R package called frailtypack. This package allows to fit Cox models and four types of frailty models (shared, nested, joint, additive) that could be useful for several issues within biomedical research. It is well adapted to the analysis of recurrent events such as cancer relapses and/or terminal events (death or lost to follow-up). The approach uses maximum penalized likelihood estimation. Right-censored or left-truncated data are considered. It also allows stratification and time-dependent covariates during analysis

Design and Construction of a High-Speed Match Index of Refraction Facility

The design and construction of a recirculating high speed matched index of refraction facility will aim to provide a deeper understanding of isothermal turbulent mixing at a fundamental level. The understanding of this fluid flow phenomena will allow a greater understanding of the thermal hydraulic challenges found in generation IV (Gen IV) reactors and fluid thermal systems. Particle image velocimetry combined with matching index will provide unobstructed data acquisition and increase optical access in the region of interest. Mineral oil is used, as the working fluid, in combination with two 24-inch long quartz plates to achieve index matching. The two quartz plates will be inserted in a test section which will form three channels. The test section was designed with the goal of achieving a slot channel Reynolds number of at least 10,000. A 5th order polynomial contraction was also designed with the purpose to generate a uniform velocity profile before the test section’s inlet. In conjunction with the contraction, a flow conditioner was placed three hydraulic diameters upstream of the contraction’s inlet with the goal to reduce turbulence intensity in the flow. Two expansions were also designed in order to connect different pipe sizes and geometries in the pipe system while minimizing flow separation. The pressure drop of the system was theoretically analyzed and a 20 horsepower inline centrifugal pump was selected based on the results and it is expected to operate with an efficiency between 86% and 79%. Design and construction of the facility is completed along with filling the facility with mineral oil. Leaks in the system were addressed and fixed in order to ensure a leak tight construction. After the building electrical accommodations are adjusted, experiments can be initiated

Optimización del Tratamiento Térmico de Productos Tubulares de Acero

[Optimization of Heat Treatment of Steel Tubular Products] El problema a abordar es el de la optimización del tratamiento térmico de productos tubulares de acero, presente en la empresa siderúrgica Tenaris. Más específicamente, se estudia el problema de dar un tratamiento adecuado a cargas retenidas en el horno de revenido. En este caso, el tratamiento térmico se compone de un primer calentamiento de los tubos a temperaturas cercanas a los 900°C, en el que se austeniza el material, seguido por un enfriamiento rápido en el que el material se transforma en martensita. Esta etapa constituye el templado del acero. Para lograr las propiedades metalúrgicas finales especificadas para el producto se realiza un segundo calentamiento a temperaturas entre 500 y 700°C, que se denomina revenido. Para simplificar el análisis, en este trabajo se considera una única propiedad metalúrgica, la dureza, que para el producto que se analiza debe estar en el rango de 270-300 Hv

A neural network-based method for spruce tonewood characterization

The acoustical properties of wood are primarily a function of its elastic properties. Numerical and analytical methods for wood material characterization are available, although they are either computationally demanding or not always valid. Therefore, an affordable and practical method with sufficient accuracy is missing. In this article, we present a neural network-based method to estimate the elastic properties of spruce thin plates. The method works by encoding information of both the eigenfrequencies and eigenmodes of the system and using a neural network to find the best possible material parameters that reproduce the frequency response function. Our results show that data-driven techniques can speed up classic finite element model updating by several orders of magnitude and work as a proof of concept for a general neural network-based tool for the workshop. © 2023 Acoustical Society of America

Computation of Electrostatic Field near Three-Dimensional Corners and Edges

Theoretically, the electric field becomes infinite at corners of two and three dimensions and edges of three dimensions. Conventional finite-element and boundary element methods do not yield satisfactory results at close proximity to these singular locations. In this paper, we describe the application of a fast and accurate BEM solver (which usesexact analytic expressions to compute the effect of source distributions on flatsurfaces) to compute the electric field near three-dimensional corners and edges. Results have been obtained for distances as close as 1$\mu m$ near the corner/edge and good agreement has been observed between the present results and existing analytical solutions.Comment: Presented in International Conference on Computational and Experimental Engineering and Sciences held at IIT Madras, Chennai, India, during 1-6 December, 200