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La qualité de vie des séniors : Analyse et déterminants
No full textAvec l’arrivée des générations du baby-boom aux âges élevés et l’allongement continu de l’espérance de vie, le pays compte chaque jour davantage de personnes âgées. Cela doit nous inciter à modifier notre manière de penser l’âge : un sénior de 70 ans d’aujourd’hui ressemble, en termes de santé et d’autonomie, à un sexagénaire d’il y a quelques décennies (Bonnet et al, 2021). Cependant, si les progrès médicaux et sociaux ont permis à davantage de personnes – y compris les plus fragiles – d’atteindre un âge avancé, ils ne suppriment pas totalement les troubles fonctionnels. L’augmentation du nombre de seniors impose donc de repenser les politiques publiques, de renforcer les moyens et d’améliorer la qualité de l’accompagnement, à domicile comme en établissement, pour répondre aux attentes des personnes âgées et de leurs aidants. Dans le cadre de son projet d’étude sur la qualité de vie des séniors sur le département du Nord, et afin d’identifier d’éventuels leviers pour améliorer leur qualité de vie, un questionnaire a été administré au cours du premier semestre de l’année 2025 par l’association Debout Les Ainé-e-s (DLA) sur plus de 800 ainés du Sud de la Métropole lilloise, incluant la Communauté de communes Pévèle-Carembault. Environ 80 enquêteurs bénévoles de l’association (des aînés eux-mêmes en majorité) sont intervenus la plupart du temps à domicile. Le temps d’entretien était d’environ 1h par personne. Cette enquête a notamment visé à collecter des informations sur la qualité de vie perçue des séniors, puis à approfondir plusieurs champs qui y sont liés. Pour cela, les caractéristiques socio-démographiques, le bien-être psychologique et émotionnel, la santé, l’autonomie, le domicile et son environnement, la vie familiale et amicale, la vie sociale et associative, la situation financière, et enfin les valeurs et la spiritualité, ont été abordées.La combinaison des différentes approches qualitatives (analyse de discours et lexicométrie) et quantitatives (statistiques, modélisation et analyse de données) ont permis de décrire la population des séniors et d’identifier les potentiels déterminants du niveau de leur qualité de vie
Biomechanical analysis of spinal range of motion and intervertebral disc loadings in normal and adolescent idiopathic scoliosis models
No full textInternational audienceObjective While the Lenke classification enhances our structural understanding of adolescent idiopathic scoliosis (AIS), the biomechanical implications for spinal range of motion (ROM) and intervertebral disc (IVD) loadings remain unclear. This study aims to quantitatively explore and compare these biomechanical responses in normal thoracolumbar spines and those with various curvatures of Lenke types under pure bending conditions. Methods The baseline thoracolumbar finite element (FE) model was derived from a comprehensive human body FE model, validated, and calibrated against spinal responses under dynamic compression and quasi-static bending conditions. Using mesh morphing, AIS models of Lenke 1, Lenke 2, Lenke 3, and Lenke 5 were established to represent their respective spinal curvatures. Pure bending moments of ±7.5 Nm in flexion-extension, lateral bending, and axial rotation were applied to both normal and AIS models. Global spinal ROM and ROM of spinal segments T1-T6, T7-T12, and L1-Sacrum were measured under each loading condition. IVD mechanical loadings, including force, moment, and VonMises stress, were also evaluated and compared across all models. Results AIS models showed higher principal ROM compared to the normal model, with Lenke 2 having the highest ROM from T1-Sacrum and Lenke 3 the highest ROM from T6-12. AIS models exhibited more asymmetry in segmental ROM, particularly in the lumbar spine during lateral bending and axial rotation. IVD mechanical loadings varied significantly between normal and AIS models, influenced by spinal curvature types. AIS models had higher secondary moments and shear forces, especially under flexion-extension. The highest stress was mostly observed in the frontal IVD regions under flexion which was greatly reduced under extension. Lateral bending caused the highest stress predominantly on the same side as the loading direction in the IVD regions. The IVDs of T6-T7 and T12-L1 showed even stress distribution under axial rotation, while the right IVD regions of L5-Sacrum sustained the highest stress under right axial rotation, and the left regions under left axial rotation. In Lenke 3 and Lenke 5 models, the right (concave) regions of the T12-L1 IVD consistently sustained higher stress levels, regardless of the loading conditions applied. Conclusion This study underscores significant biomechanical differences between normal and AIS models, revealing intricate interactions within scoliotic spines and enhancing our understanding of AIS biomechanics. These insights can aid in better diagnosis, treatment planning, and prognosis. Extension-focused therapeutic exercises may reduce stress on anterior IVDs, potentially lowering the risk of low back pain or disc herniation, while careful management of rotational exercises can help minimize stress in the lower lumbar regions
A practical guide to using games in university teaching
No full textTimes Higher EducationWhat is game-oriented learning, what criteria must games follow to have true educational value and how to use them in your own teaching? Find out her
Goodness-of-fit testing for the stationary density of a size-structured PDE
No full textWe consider two division models for structured cell populations, where cells can grow, age and divide. These models have been introduced in the literature under the denomination of 'mitosis' and 'adder' models. In the recent years, there has been an increasing interest in biology to understand whether the cells divide equally or not, as this can be related to important mechanisms in cellular aging or recovery. We are therefore interested in testing the null hypothesis where the division of a mother cell results into two daughters of equal size, against the alternative hypothesis where the division is asymmetric and ruled by a kernel that is absolutely continuous with respect to the Lebesgue measure. The sample consists of i.i.d. observations of cell sizes and ages drawn from the population, and the division is not directly observed. The hypotheses of the test are reformulated as hypotheses on the stationary size and age distributions of the models, which we assume are also the distributions of the observations. We propose a goodness-of-fit test that we study numerically on simulated data before applying it on real data
Performance des Sols Argileux Renforcés par Inclusions Rigides sous Chargements Sismiques : Modélisation en Centrifugeuse et Numérique
No full textThe rigid inclusion (RI) reinforcement system improves the performance of shallow foundations in weak soils by limiting settlement and increasing bearing capacity. The RI system is characterized by the presence of the load transfer platform between the pile head and the footing, which distributes the load from the superstructure to the RIs and the surrounding soil. The technique of RI reinforcement has become increasingly appreciated when used under stiff structures, such as bridge piers or nuclear power plants.The seismic performance of stiff structures founded on RI systems involves complex soil–structure interaction (SSI) mechanisms. During earthquake loading, the ground motion is influenced by the movement of the RIs (kinematic interaction, KI) and by inertial forces transmitted from the stiff superstructure (inertial interaction, II). Only a limited number of studies have investigated these seismic SSI mechanisms in the context of RI systems, particularly in soft clay soils. Therefore, this project aims to advance the current understanding of the seismic behavior of stiff structures supported by RI systems through an extensive experimental campaign and numerical simulations.A series of dynamic centrifuge tests is carried out using a multilayered soil profile, seven RIs arranged in a circular pattern, and two rigid structures of equal weight: a slender and a short. The models are subjected to a series of base shaking composed of mono- and multi-frequency motions with varying intensities. Several interaction mechanisms are explored, including the influence of RIs on the behavior of the structure, the effect of the structure on internal efforts within the RIs, and the impact of the slender ratio on the response of the soil-RI-structure system.A 3D finite element model (FEM) was developed, calibrated, and validated using the centrifuge test results. It enabled a series of parametric studies to investigate the influence of key components in the soil–RI–structure system that are not explored experimentally. These include the thickness of the LTP, the load-carrying condition of the RIs, and their stiffness.Le système de renforcement des sols par inclusions rigides (IR) améliore la performance des fondations superficielles sur sols mous en limitant les tassements et en augmentant leur capacité portante. Il se caractérise par la présence d’une plateforme de transfert de charge (PTC) installée entre la tête des IR et la fondation, qui transmet les efforts verticaux provenant de la superstructure aux IR et au sol environnant. Cette technique est particulièrement utilisée sous des ouvrages à forte raideur, tels que les piles de ponts ou les centrales nucléaires.La performance sismique des structures rigides fondées sur des systèmes d’IRs implique des mécanismes complexes d’interaction sol-structure (ISS). Sous chargement sismique, le mouvement du sol est influencé à la fois par le déplacement des IRs (interaction cinématique, IC) et par les forces d’inertie transmises depuis la superstructure rigide (interaction inertielle, II). Dans les sols argileux mous, seul un nombre limité d’études a examiné ces mécanismes d’ISS dans le contexte des systèmes à IRs. Ainsi, ce projet vise à enrichir les connaissances actuelles sur le comportement sismique des structures rigides fondées sur des systèmes d’IRs, à travers une campagne expérimentale et des simulations numériques.Une série d’essais dynamiques en centrifugeuse a été réalisée avec un profil de sol multicouche, sept IR disposées selon une configuration circulaire, et deux structures rigides de même poids : l’une élancée et l’autre courte. Les modèles sont soumis à une série de sollicitations dynamiques, composée de signaux mono- et multi-fréquentiels à intensités variables. Plusieurs mécanismes d’interaction sont étudiés, notamment l’influence des IRs sur le comportement de la structure, l’effet de la structure sur les efforts internes dans les IRs, ainsi que l’impact de l’élancement de la structure sur la réponse du système sol–IR–structure.Un modèle numérique 3D par éléments finis (MEF) a été développé, calibré et validé à partir des résultats des essais en centrifugeuse. Il permet l’exécution d’une série d’études paramétriques afin d’analyser l’influence de composants clés du système sol–IR–structure qui ne peuvent pas être explorés expérimentalement. Ces paramètres incluent notamment l’épaisseur de la plateforme de transfert de charge (PTC), les conditions de report de charge des IRs, ainsi que leur raideur
Enhanced Raman hyperspectral imaging using RS-NMF: a novel Regularized Sparse Non-negative Matrix Factorization for spectral unmixing
No full textInternational audienceMolecular spectroscopy is a powerful, non-destructive technique for chemical analysis, as the sample remains unaltered during the measurement. Although it is essential for getting meaningful information, it often suffers from spectral overlap, making it challenging to identify individual components within a sample. Therefore, for over fifty years, a plethora of mathematical approaches have been developed to unmix complex signals and push the detection limits of spectroscopic instruments, such as Blind Source Separation (BSS) or Multivariate Curve Resolution (MCR), to name but a few. However, despite these numerous advances, and even as the amount of data increasespotentially providing more informationthey continue to face inherent limitations (i.e., selectivity problems), particularly when dealing with contemporary samples, making their thorough characterization an increasingly intricate challenge, especially with diminishing prior knowledge. This article presents a novel signal unmixing method applied to hyperspectral Raman imaging designed to overcome these limitations. Our approach, based on a Non-Negative Matrix Factorization (NMF), addresses critical challenges such as rotational ambiguity and noise sensitivity, which often prevent accurate pure component spectral unmixing. First, we introduce our methodology and explain how it differs from existing mathematical methods.We then evaluate its performance on a well-known real-world dataset in the chemometrics community called "emulsion" from hyperspectral Raman imaging. To further challenge our method, we apply it to a complex simulated molecular signal dataset. Finally, we compare our results with those obtained using the standard MCR-ALS approach. Our initial results demonstrate that this RS-NMF approach improves the unmixing of complex signals.</p
Load‐Finding: a Form‐Finding Method for Plane‐Faced Funicular Gridshells
No full textInternational audienceGridshells and shells are geometrical objects that must comply with mechanical and manufacturing constraints. Being funicular, and having planar panels (for discretized structures) is a combination of constraints often searched and studied in the literature. The study of funicular structures is the subject of graphic statics, with the panel planarity constraint added in methods using the Airy stress function. It is proposed in this paper to reverse the existing procedures and to present a “load‐finding” method: rather than creating structures with almost flat panels, we design almost funicular grids with perfectly flat panels. We hence use lifting methods with strict control over geometrical properties and we prescribe heights and forces at the boundary to calculate the load under which the structure operates without bending, i.e. the funicular load associated with the structure. We can then optimize the lift to find the load which will be the closest to a target distribution. We hence get a space of planar faced polyhedra in equilibrium under a certain load that projects onto the input mesh, and which is controlled by heights and forces defined on guide curves. The funicular load deviation is a purely static tool for locating and quantifying loads that cause moments in the structure. A finite element analysis of the structures produced opens a discussion on the influence of the parameters and metric chosen in our method, as well as on certain biases introduced by our method and a method using an elastic calculation
Étude et conception d’un capteur résonnant différentiel à double cavité pour des petits échantillons liquides
No full textInternational audienceCe papier a pour objet le développement et la caractérisation d’un capteur RF différentiel pour la caractérisation de petits volumes d’échantillons liquides. La structure proposée est constituée d’une ligne micro-ruban associée à deux résonateurs dimensionnés pour une résonance à vide à 1,89 GHz. Les résultats de mesure prouvent la sensibilité du capteur aux liquides étudiés et montre la flexibilité de son utilisation grâce à la présence de deux cavités par résonateur
Projet Plasti-nium (2021-2025) : présentation du plateau Technique Plastique
No full textInternational audienc
A methodology for stock assessment and traceability at the component level: the case of structural steel reuse
No full textInternational audienceTo reduce the environmental burden of the construction industry, reusing reclaimed steel instead of recycling it is seen as a promising option to move the structural steel industry towards a more circular economy. Assessing the material composition of the built environement is key to develop efficient circular stategies. Reliable sectorial data is required, per material type. This paper unvails the potentials of using first-hand construction documents to assess material stocks of structural steel within existing industrial buildings. It integrates into a bottom-up Material Flow Analysis (MFA) framework. A component-based archetype of an industrial steel structure is defined and its material composition is calibrated thanks to construction documents of built structures. The accuracy of stock evaluation will depend on the number and the variety of buildings available in the dataset. Data extraction from the available construction documents is still ongoing. Yet, the proposed method provides valuable insights on the potentials of construction document-based archetypes. As for future reuse strategies, leveraging such documentation is also interesting to ensure the traceability of today’s buildings. This paper explores the opportunities offered by construction documents in relation with state-of-the-art methods that aims at designing structures from reclaimed elements. Shipping lists are identified as highly relevant to inform decision-making on future reuse alternatives