Search results for "quantitative"

The importance of level stratification for quantitative MR studies of lumbar intervertebral discs : a cross-sectional analysis in 101 healthy adults

2019

Purpose: To investigate whether quantitative T2-times depend on lumbar intervertebral disc (IVD) level. Methods: The lumbar spine (Th12/L1–L5/S1) of 101 participants (53.5% female, 30.0[± 3.6]years, 173.5[± 9.6]cm and 69.9[± 13.4]kg), without history of back pain, was examined on a 3T scanner with sagittal T2-mapping. All IVDs were stratified according to Pfirrmann grade and lumbar level, with mean T2-time determined for the entire IVD volume and in five subregions of interests. Results: Significant level-dependent T2-time differences were detected, both for the entire IVD volume and its subregions. For the entire IVD volume, Pfirrmann grade 2 IVDs displayed 9–18% higher T2-times in Th12/L1…

A contribution to the mathematical modeling of immune-cancer competition

2018

Abstract This paper deals with the modeling of interactions between the immune system and cancer cells, in the framework of the mathematical kinetic theory for active particles. The work deepens a previous paper of Belloquid et al. that assumes spatial homogeneity and discrete values of the activity of cancer and immune cells. A number of simulations are made with the aim to investigate how the state of the various cell populations evolves in time depending on the choice of the free parameters.

Inhomogeneous vortex tangles in counterflow superfluid turbulence: flow in convergent channels

2016

Abstract We investigate the evolution equation for the average vortex length per unit volume L of superfluid turbulence in inhomogeneous flows. Inhomogeneities in line density L andincounterflowvelocity V may contribute to vortex diffusion, vortex formation and vortex destruction. We explore two different families of contributions: those arising from asecondorder expansionofthe Vinenequationitself, andthose whichare notrelated to the original Vinen equation but must be stated by adding to it second-order terms obtained from dimensional analysis or other physical arguments.

Discontinuous Galerkin semi-Lagrangian method for Vlasov-Poisson

2011

We present a discontinuous Galerkin scheme for the numerical approximation of the one-dimensional periodic Vlasov-Poisson equation. The scheme is based on a Galerkin-characteristics method in which the distribution function is projected onto a space of discontinuous functions. We present comparisons with a semi-Lagrangian method to emphasize the good behavior of this scheme when applied to Vlasov-Poisson test cases. Une méthode de Galerkin discontinu est proposée pour l’approximation numérique de l’équation de Vlasov-Poisson 1D. L’approche est basée sur une méthode Galerkin-caractéristiques où la fonction de distribution est projetée sur un espace de fonctions discontinues. En particulier, …

Parallel Computing for the study of the focusing Davey-Stewartson II equation in semiclassical limit

2012

The asymptotic description of the semiclassical limit of nonlinear Schrödinger equations is a major challenge with so far only scattered results in 1 + 1 dimensions. In this limit, solutions to the NLS equations can have zones of rapid modulated oscillations or blow up. We numerically study in this work the Davey-Stewartson system, a 2 + 1 dimensional nonlinear Schrödinger equation with a nonlocal term, by using parallel computing. This leads to the first results on the semiclassical limit for the Davey-Stewartson equations.

Engaging universities in social innovation research for understanding sustainability issues

2017

International audience; The paper presents the analysis of a three-stage research conducted by the authors within a social innovation project in collaboration with international master students of Riga Technical University for determining the factors, which motivate people to be involved in the solution of social problems. The authors not only analyse and use the outcomes of the students’ research but also provide feasibility study of using the potential of study research at the university, for implementing serious research projects. Data collection from Africa, Asia, America and Europe was organised jointly by all the students via web-based survey for creating an original data base for the…

Towards modern understanding of the Achilles tendon properties in human movement research

2023

The Achilles tendon (AT) is the strongest tendon in humans, yet it often suffers from injury. The mechanical properties of the AT afford efficient movement, power amplification and power attenuation during locomotor tasks. The properties and the unique structure of the AT as a common tendon for three muscles have been studied frequently in humans using in vivo methods since 1990's. As a part of the celebration of 50 years history of the International Society of Biomechanics, this paper reviews the history of the AT research focusing on its mechanical properties in humans. The questions addressed are: What are the most important mechanical properties of the Achilles tendon, how are they stud…

Analyse économique du temps libre

1984

International audience; Un type de société génère sa théorisation économique ; celle-ci à son tour façonne une idée du temps qui reflète l'organisation et l'utilisation du temps dans la société. Avant que n'apparaissent les promesses et les problèmes du temps libre, un long trajet technologique et social a du être parcouru. Mais c'est la traduction méthodologique de ce trajet par les économistes qui a semblé la plus suggestive et c'est de ce type de discours que l'auteur a tenté ici d'esquisser l'évolution. Ainsi, sont brièvement retracés l'association originelle entre temps et travail, puis le détachement progressif du temps des activités de production, son rapprochement avec la consommati…

Specifications for the software “PRAGMA” of quantitative collection and treatment software

2006

2,4-Di-tert-butyl-6-({[2-(di-methyl-amino)-eth-yl](2-hy-droxy-benz-yl)amino}-meth-yl)phenol.

2014

The title compound, C26H40N2O2, has both its N atoms in trigonal-pyramidal geometries. The molecular structure is stabilized by O—H...N and C—H...O hydrogen bonds. In the crystal, C—H...π interactions lead to the formation of a supramolecular helical chain along theb-axis direction.