The Variational Theory of Complex Rays: An answer to the resolution of mid-frequency 3D engineering problems

International audienceThe Variational Theory of Complex Rays (VTRC) is an approach to the simulation of mid-frequency phenomena whose wavelengths are relatively small compared to the dimensions of the domain. This is a wave-based computational technique which involves a nonclassical variational formulation. This paper focuses on the development of the approach for 3D engineering problems and shows that it is a mature technique. Illustrations are given to show the capabilities of this method

The Variational Theory of Complex Rays for three-dimensional Helmholtz problems

International audienceThis article proposes an extension of the Variational Theory of Complex Rays (VTCR) to three-dimensional linear acoustics, The VTCR is a Trefftz-type approach designed for mid-frequency range problems and has been previously investigated for structural dynamics and 2D acoustics. The proposed 3D formulation is based on a discretization of the amplitude portrait using spherical harmonics expansions. This choice of discretization allows to substantially reduce the numerical integration work by taking advantage of well-known analytical properties of the spherical harmonics. It also permits (like with the previous 2D Fourier version) an effective \emph{a priori} selection method for the discretization parameter in each sub-region, and allows to estimate the directivity of the pressure field by means of a natural definition of rescaled amplitude portraits. The accuracy and performance of the proposed formulation are demonstrated on a set of numerical examples that include results on an actual case study from the automotive industry

Evaluation du rôle des vecteurs potentiels dans la circulation du virus Amaril, en 1987 au Sénégal et dans le sud de la République Islamique de Mauritanie

Ce rapport consigne le déroulement de trois enquêtes réalisées sur suspicion de cas humains de fièvre jaune. La première s'est déroulée dans la région de Kaolack, la seconde dans la région de St Louis et la troisième dans celle de Rosso (R.I.M

Porous polycrystal plasticity modeling of neutron-irradiated austenitic stainless steels

A micromechanical model for quantifying the simultaneous influence of irradiation hardening and swelling on the mechanical stiffness and strength of neutron-irradiated austenitic stainless steels is proposed. The material is regarded as an aggregate of equiaxed crystalline grains containing a random dispersion of pores (large voids due to large irradiation levels) and exhibiting elastic isotropy but viscoplastic anisotropy. The overall properties are obtained via a judicious combination of various bounds and estimates for the elastic energy and viscoplastic dissipation of voided crystals and polycrystals. Reference results are generated with full-field numerical simulations for dense and voided polycrystals with periodic microstructures and crystal plasticity laws accounting for the evolution of dislocation and Frank loop densities. These results are calibrated with experimental data available from the literature and are employed to assess the capabilities of the proposed model to describe the evolution of mechanical properties of highly irradiated Solution Annealed 304L steels at 330°C. The agreement between model predictions and simulations is seen to be quite satisfactory over the entire range of porosities and loadings investigated. The expected decrease of overall elastic properties and strength for porosities observed at large irradiation levels is reported. The mathematical simplicity of the proposed model makes it particularly apt for implementation into finite-element codes for structural safety analyses.Centro Tecnológico Aeroespacia

Growth of white matter in the adolescent brain: role of testosterone and androgen receptor

The growth of white matter during human adolescence shows a striking sexual dimorphism; the volume of white matter increases with age slightly in girls and steeply in boys. Here, we provide evidence supporting the role of androgen receptor (AR) in mediating the effect of testosterone on white matter. In a large sample of typically developing adolescents (n = 408, 204 males), we used magnetic resonance imaging and acquired T1-weighted and magnetization transfer ratio (MTR) images. We also measured plasma levels of testosterone and genotyped a functional polymorphism in the AR gene, namely the number of CAG repeats in exon 1 believed to be inversely proportional to the AR transcriptional activity. We found that the testosterone-related increase of white-matter volume was stronger in male adolescents with the lower versus higher number of CAG repeats in the AR gene, with testosterone explaining, respectively, 26 and 8% of variance in the volume. The MTR results suggest that this growth is not related to myelination; the MTR decreased with age in male adolescents. We speculate that testosterone affects axonal caliber rather than the thickness of the myelin sheath

Власні назви як елемент інтертекстуальності в поетичних творах XX століття

У роботі розглядаються проблеми інтертекстуальності та аналізуються власні назви як самостійні елементи інтертекстуальних зв’язків на матеріалі поетичних творів ХХ століття. Досліджуються особливості інтерпретації онімів як конденсованих символів, індивідуально- авторського переосмислення контексту світової і національної культури та історії у творах “неокласиків”. Розглядаються семантичні особливості художнього мовлення, визначаються функції, семантико-стилістичні та структурні особливості мовних засобів, простежуються тенденції своєрідного вживання власних назв у творчості “неокласиків”.В работе рассматриваются проблемы интертекстуальности и анализируются имена собственные как самостоятельные элементы интертекстуальных связей на материале поэзии ХХ столетия. Исследуются особенности интерпретации онимов как конденсированных символов, индивидуально-авторского переосмысления контекста мировой и национальной культуры и истории в творчестве “неоклассиков”. Рассматриваются семантические особенности художественной речи, семантико-стилистические и структурные особенности языковых средств, прослеживаются тенденции своеобразного использования имен собственных в творчестве “неоклассиков”.In work deals with the problems of intertextuality and analyzed their own names as separate elements intertextual connections on the material of poetry of the twentieth century. Investigates the features of the interpretation onyms as condensed symbols of author individual rethinking the context of global and national culture and history in the work of "neoclassicists". Lexical variety and semantic peculiarities of artistic language are examined. The functions, semantic-stylistic and structural peculiarities of language means are defined. The tendencies of distinctive word usage in language creativity of “neoclassics” are revealed and scientifically grounded

Detection of quantitative trait loci for growth and fatness in pigs

A quantitative trait locus (QTL) analysis of growth and fatness data from a three-generation experimental cross between Meishan (MS) and Large White (LW) pig breeds is presented. Six boars and 23 F1 sows, the progeny of six LW boars and six MS sows, produced 530 F2 males and 573 F2 females. Nine growth traits, i.e. body weight at birth and at 3, 10, 13, 17 and 22 weeks of age, average daily gain from birth to 3 weeks, from 3 to 10 weeks and from 10 to 22 weeks of age, as well as backfat thickness at 13, 17 and 22 weeks of age and at 40 and 60 kg live weight were analysed. Animals were typed for a total of 137 markers covering the entire porcine genome. Analyses were performed using two interval mapping methods: a line-cross (LC) regression method where founder lines were assumed to be fixed for different QTL alleles and a half-/full-sib (HFS) maximum likelihood method where allele substitution effects were estimated within each half-/full-sib family. Both methods revealed highly significant gene effects for growth on chromosomes 1, 4 and 7 and for backfat thickness on chromosomes 1, 4, 5, 7 and X, and significant gene effects on chromosome 6 for growth and backfat thickness. Suggestive QTLs were also revealed by both methods on chromosomes 2 and 3 for growth and 2 for backfat thickness. Significant gene effects were detected for growth on chromosomes 11, 13, 14, 16 and 18 and for backfat thickness on chromosome 8, 10, 13 and 14. LW alleles were associated with high growth rate and low backfat thickness, except for those of chromosome 7 and to a lesser extent early-growth alleles on chromosomes 1 and 2 and backfat thickness alleles on chromosome 6