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Impact of information processing speed on episodic memory in multiple sclerosis: insights from survival analysis
No full textInternational audienceBackground: Standardized episodic memory tests often impose time limits, obscuring whether poor performance in Multiple Sclerosis (MS) is due to cognitive or Information Processing Speed (IPS) deficits.Method: We assessed episodic memory performance on the Selective Reminding Test (SRT) in 157 persons with MS (pwMS) and 109 healthy controls using survival analysis to examine the number of trials required for two consecutive full recalls of a word list (SRT-goal). Survival analysis focuses on when a particular event occurs and appears appropriate to characterize the slow vs. rapid progression of learning in pwMS.Results: Results showed a significant difference among pwMS and control: the mean survival times decreased from 10.23 trials in patients to 8.52 trials in controls, indicating that controls achieved the task sooner than patients (p < .001). Among pwMS, those with preserved IPS reached the SRT-goal in a median of 9.71 trials, while those with impaired IPS took 10.67 trials on average (p < .001). Only 12.5% of IPS-impaired pwMS achieved the SRT goal, compared with 60% of those with preserved IPS. Comparing MS-subtypes, 60% of relapsing-remitting MS (RRMS) patients reached the SRT goal, whereas only 15.8% of secondary progressive MS (SPMS) and 15% of primary progressive MS (PPMS) patients did.Conclusions: Survival analysis provides a complementary assessment of episodic memory to traditional paradigms and an innovative way to address slow-learning in MS. This study presents clinical lessons in the assessment of episodic memory and cognitive rehabilitation of pwMS
Structural, morphological and optical properties of ZnO thin films grown by time-dependent chemical bath deposition
No full textInternational audienceThis study investigates the effect of deposition time on the structural, morphological, and optical properties of ZnO thin films synthesized by single-step chemical bath deposition (CBD) without the use of a seed layer. The films were systematically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and UV-Visible spectroscopy in order to establish correlations between growth conditions and film properties. XRD analysis confirmed that all synthesized films are polycrystalline and crystallize in the hexagonal wurtzite structure, with average lattice parameters of a = 3.247 Å and c = 5.209 Å. The crystallite size increased slightly from 13.27 nm to 14.05 nm with increasing deposition time, indicating improved structural ordering and crystallinity. FTIR spectra verified the presence of characteristic Zn-O vibrational modes together with surface hydroxyl groups and other functional bonds related to the growth process. SEM images revealed a strong dependence of surface morphology on deposition time: ZnO microrods evolved from loosely distributed to more compact and densely packed assemblies as the deposition progressed, confirming enhanced film coverage. Optical measurements highlighted significant modifications in the transparency and band structure of the films. The average optical transmittance in the visible range decreased progressively from 68% to 52% when deposition time was extended from 30 to 120 minutes, reflecting increased film density. Concurrently, the optical band gap narrowed from 3.27 eV to 3.22 eV. These findings demonstrate that single-step CBD provides a reliable and controllable route for synthesizing ZnO thin films with tunable physical properties
Élaboration d'un éco-béton durable : Étude de faisabilité et compatibilité multiphysique entre les granulats recyclés et les ciments dits « bas carbone ».
No full textInternational audienceCette étude vise à élaborer un éco-béton à base de granulats recyclés (sables et gravillons) issus des déchets de déconstruction générés par le projet Grand Paris Express. Elle s'inscrit dans une démarche visant à surmonter les défis posés par l'hétérogénéité des granulats recyclés et à analyser leurs interactions avec les ciments dits « bas carbone ». Ce travail comprend une étude de faisabilité et de compatibilité multiphysique entre les granulats recyclés et ciments bas carbone. L'objectif principal est d'optimiser la formulation de l'éco-béton pour garantir des performances mécaniques et environnementales conformes aux normes actuelles tout en assurant une durabilité à long terme. Ce travail s'inscrit dans une démarche d'économie circulaire en valorisant les ressources locales et en réduisant l'empreinte carbone dans le secteur du bâtiment. Il contribue ainsi à proposer des solutions durables pour la gestion des déchets de déconstruction
Identification of early behavioural traits to predict injurious pecking in laying hens
No full textInternational audienceInjurious pecking (IP) represents a major challenge for the egg industry, compromising both welfare and productivity. We aimed to determine whether specific behavioural traits in pullets could predict later pecking behaviour. We tested Lohmann Brown and Lohmann LSL hens (N = 90 per strain) housed in floor pens in groups of 10 in a battery of tests at two ages (5-10 and 18-23 weeks). Each battery included a detour test, a modified cognitive bias test, a multivariate test, a novel object (NO) test performed in the home-pen and a tonic immobility (TI) test. The detour test involved a U-shaped compartment with a grid front, facing a mirror and food. To access them, the bird had to perform a detour, meaning temporarily losing their sight. In the multivariate test, birds were placed in an arena containing two conspecifics in a central compartment and four panels restricting visual contact, forming three virtual zones: near conspecifics, farther away with or without visual contact. Altogether, these tests assessed cognitive performance, social motivation, foraging, fearfulness and proactivity. Between 31 and 38 weeks, IP was assessed via direct observations (6.5 hours per bird). For each strain, the 20 birds performing the most (P+) and least (P-) IP were selected for analysis. Tests results were analysed using Generalised or Linear Mixed-Effects models, or survival analysis for censored latencies. Results showed that, regardless of the strain, P+ were faster and more likely to perform the detour at 5 weeks (P+: 167 s vs P-: 204 s; χ² = 4.1, p = 0.04). At 21 weeks, they were also slower and less likely to approach the negative stimulus in the cognitive bias test (P+: 111 s vs P-: 62.4 s; χ² = 4.4, p = 0.03) and had a shorter duration of TI (P+: 124 s vs P-: 181 s; χ² = 3.7, p = 0.05). In Lohmann Brown only, P+ spent less time foraging during the multivariate test at 20 weeks (P+: 47 s vs P-: 74 s; t(72.8) = 2, p = 0.05) and spent more time near conspecifics (P+: 222 s vs P-: 172 s; t(72.8) = -2.3, p = 0.02). No significant effects were found in the NO test. These results suggest that future peckers may be more socially motivated and proactive, but early predictors of IP appear strain- and context-dependent, implying a complex relationship between early-behaviour and IP later in life
Une alliance digitale en chine pour courbet, pionnier français du diamant de synthèse
No full textInternational audienceIn 2021, three years after co-founding Courbet, the first fine jewellery brand from Place Vendôme to position itself on the eco-responsible luxury market (synthetic diamonds and recycled gold from used electronic equipment), Manuel Mallen is launching his international business. He has set his sights on China. Only country whose luxury goods market continued to grow during the Covid 19 pandemic, it offers attractive economic prospects for a French brand. To boost its entry into the Middle Kingdom, establish its reputation and legitimacy, and maximise its impact with the ultra-connected Millenials and Z generations, the CEO is deploying a digital strategy and banking on the aura of a actress-influencer with 50 million subscribers. A union for the better... but also for the worse. This case study explores the challenges of influencer marketing, which is increasingly used by brands around the world, but also to consider the risks involved.En 2021, trois ans après avoir co-fondé Courbet, première maison de haute-joaillerie de la place Vendôme à se positionner sur le marché du luxe éco-responsable (diamants de synthèse et or recyclé issu d’appareils électroniques usagés), Manuel Mallen se lance à l’international et cible la Chine. Seul pays dont le marché du luxe est resté en croissance pendant la pandémie de la Covid 19, il présente des perspectives économiques attractives pour une marque française. Afin de booster son entrée dans l’Empire du milieu, asseoir sa notoriété et sa légitimité, et maximiser son impact auprès des Milléniaux et des Z, générations ultra-connectées, le dirigeant déploie une stratégie digitale : il mise sur l’aura d’une actrice-influenceuse aux 50 millions d’abonnés. Une union pour le meilleur… mais aussi pour le pire. Le cas invite à investiguer les enjeux du marketing d’influence, de plus en plus utilisé par les marques du monde entier, mais aussi à réfléchir aux risques encourus