Search results for "Jacob"
showing 10 items of 181 documents
Mappings of finite distortion: the degree of regularity
2005
This paper investigates the self-improving integrability properties of the so-called mappings of finite distortion. Let K(x)⩾1 be a measurable function defined on a domain Ω⊂Rn,n⩾2, and such that exp(βK(x))∈Lloc1(Ω), β>0. We show that there exist two universal constants c1(n),c2(n) with the following property: Let f be a mapping in Wloc1,1(Ω,Rn) with |Df(x)|n⩽K(x)J(x,f) for a.e. x∈Ω and such that the Jacobian determinant J(x,f) is locally in L1log−c1(n)βL. Then automatically J(x,f) is locally in L1logc2(n)βL(Ω). This result constitutes the appropriate analog for the self-improving regularity of quasiregular mappings and clarifies many other interesting properties of mappings of finite disto…
Contrasting shell growth strategies in two Mediterranean bivalves revealed by oxygen-isotope ratio geochemistry: The case of Pecten jacobaeus and Gly…
2019
International audience; High-resolution stable-isotope ratio data (delta O-18, delta O-18) were used to study growth strategies of two bivalve species, Pecten jacobaeus (calcitic shell) and Glycymeris pilosa (aragonitic shell) from the North Adriatic Sea. The principal objectives of this study were to identify the period of the year when the growth line is formed in the shell of two target species, to identify the main growing season of these two species, to identify the environmental drivers of shell growth, and to evaluate the potential applicability of delta O-18 and delta O-18 values for the reconstruction of environmental variability. Samples were collected from the North Adriatic Sea …
The eigen-structure of the Jacobian in multi-class Lighthill-Whitham-Richards traffic flow models
2007
Characteristic-based High Resolution Shock Capturing schemes for hyperbolic systems of conservation laws require, in their basic design structure, knowledge on the complete eigen-decomposition of the Jacobian matrix of the system. For the Multi-Class Lighthill-Witham-Richards (MCLWR) Traffic flow model considered in [4], there is no explicit formula for the eigenvalues of the Jacobian matrix, which can only be determined numerically. However, once they are determined, the eigen-vectors are easily computed and straightforward formulas can be obtained by exploiting the specific structure of the Jacobian matrix in these models. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Response Power Spectrum of Multi-Degree-of-Freedom Nonlinear Systems by a Galerkin Technique
2003
This paper deals with the estimation of spectral properties of randomly excited multi-degree-of-freedom (MDOF) nonlinear vibrating systems. Each component of the vector of the stationary system response is expanded into a trigonometric Fourier series over an adequately long interval T. The unknown Fourier coefficients of individual samples of the response process are treated by harmonic balance, which leads to a set of nonlinear equations that are solved by Newton’s method. For polynomial nonlinearities of cubic order, exact solutions are developed to compute the Fourier coefficients of the nonlinear terms, including those involved in the Jacobian matrix associated with the implementation o…
On the implementation of weno schemes for a class of polydisperse sedimentation models
2011
The sedimentation of a polydisperse suspension of small rigid spheres of the same density, but which belong to a finite number of species (size classes), can be described by a spatially one-dimensional system of first-order, nonlinear, strongly coupled conservation laws. The unknowns are the volume fractions (concentrations) of each species as functions of depth and time. Typical solutions, e.g. for batch settling in a column, include discontinuities (kinematic shocks) separating areas of different composition. The accurate numerical approximation of these solutions is a challenge since closed-form eigenvalues and eigenvectors of the flux Jacobian are usually not available, and the characte…
A Flux-Split Algorithm Applied to Relativistic Flows
1998
The equations of RFD can be written as a hyperbolic system of conservation laws by choosing an appropriate vector of unknowns. We give an explicit formulation of the full spectral decomposition of the Jacobian matrices associated with the fluxes in each spatial direction, which is the essential ingredient of the techniques we propose in this paper. These techniques are based on the recently derived flux formula of Marquina, a new way to compute the numerical flux at a cell interface which leads to a conservative, upwind numerical scheme. Using the spectral decompositions in a fundamental way, we construct high order versions of the basic first-order scheme described by R. Donat and A. Marqu…
Food insecurity and physical multimorbidity among adults aged ≥ 50 years from six low- and middle-income countries
2022
Abstract Purpose Food insecurity and multimoribidity (i.e., ≥ 2 chronic conditions) may be linked bidirectionally, but there are no studies on this topic from LMICs. Therefore, the aim of the present study was to examine the association between food insecurity and physical multimorbidity in a large representative sample of older adults from six LMICs. Methods Cross-sectional, community-based data on adults aged ≥ 50 years from the World Health Organization’s Study on Global AGEing and Adult Health (SAGE) conducted in China, Ghana, India, Mexico, Russia, and South Africa were analyzed. A total of 11 chronic physical conditions were assessed. Past 12 month food insecurity was assessed with tw…
Indefinite integrals of some special functions from a new method
2015
A substantial number of indefinite integrals of special functions are presented, which have been obtained using a new method presented in a companion paper [Conway JT. A Lagrangian method for deriving new indefinite integrals of special functions. Integral Transforms Spec Funct. 2015; submitted to]. The method was originally derived from the Euler–Lagrange equations but an elementary proof is also presented in [Conway JT. A Lagrangian method for deriving new indefinite integrals of special functions. Integral Transforms Spec Funct. 2015; submitted to]. Sample results are presented here for Bessel functions, Airy functions and hypergeometric functions. More extensive results are given for th…
Osteochondroma of the coronoid process
2006
El osteocondroma es la neoplasia benigna más común del esqueleto. En la cabeza se ha descrito su localización en base de cráneo, cara posterior del maxilar, senos maxilares, y en diferentes áreas de la mandíbula, como cóndilo, rama, cuerpo y región sinfisiaria, siendo los osteocondromas coronoídeos de baja frecuencia. Presentamos una revisión de la literatura y el informe de un nuevo caso. Una mujer de 44 años que consulta por limitación de la apertura bucal y deformidad en la mejilla izquierda, de límites difusos, consistencia ósea, indolora y cubierta por piel de aspecto normal. No presentaba patología en la articulación témporomandibular. En la radiografía panorámica se evidencia un tumo…
Osteocondroma de apófisis coronoides
2006
El osteocondroma es la neoplasia benigna más común del esqueleto. En la cabeza se ha descrito su localización en base de cráneo, cara posterior del maxilar, senos maxilares, y en diferentes áreas de la mandíbula, como cóndilo, rama, cuerpo y región sinfisiaria, siendo los osteocondromas coronoídeos de baja frecuencia. Presentamos una revisión de la literatura y el informe de un nuevo caso. Una mujer de 44 años que consulta por limitación de la apertura bucal y deformidad en la mejilla izquierda, de límites difusos, consistencia ósea, indolora y cubierta por piel de aspecto normal. No presentaba patología en la articulación témporomandibular. En la radiografía panorámica se evidencia un tumo…