Portail des publications scientifiques IMT Mines Alès
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Développement d’une méthodologie de construction de système jumeaux numériques suivant une approche ingénierie système basée sur les modèles
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Marital status and risk of dementia over 18 years: Surprising findings from the National Alzheimer's Coordinating Center
No full textInternational audienceINTRODUCTION Marital status is a potential risk/protective factor for adverse health outcomes. This study tested whether marital status was associated with dementia risk in older adults. METHODS Participants ( N = 24,107; Mean age = 71.79) were from the National Alzheimer's Coordinating Center. Cox regressions tested the association between baseline marital status and clinically ascertained dementia over up to 18 years of follow‐up. RESULTS Compared to married participants, widowed (hazard ratio [HR] = 0.73, 95% confidence interval [95% CI] = 0.67–0.79), divorced (HR = 0.66, 95% CI = 0.59–0.73), and never‐married participants (HR = 0.60, 95% CI = 0.52–0.71) were at lower dementia risk, including for Alzheimer's disease and Lewy body dementia. The associations for divorced and never married remained significant accounting for demographic, behavioral, clinical, genetic, referral source, participation, and diagnostic factors. The associations were slightly stronger among professional referrals, males, and relatively younger participants. DISCUSSION Unmarried individuals may have a lower risk of dementia compared to married adults. The findings could indicate delayed diagnoses among unmarried individuals or challenge the assumption that marriage protects against dementia. Highlights Widowed, divorced, and never‐married older adults had a lower dementia risk, compared to their married counterparts. Unmarried older adults were also at a lower risk of Alzheimer's disease and Lewy body dementia, with a pattern of mixed findings for frontotemporal lobar degeneration, and no associations with risk of vascular dementia or mild cognitive impairment. All unmarried groups were at a lower risk of progression from mild cognitive impairment to dementia. There was some evidence of moderation by age, sex, and referral source. However, stratified analyses showed small differences between groups, and most interactions were not significant, suggesting that the role of marital status in dementia tends to be similar across individuals at different levels of dementia risk due to education, depression, and genetic vulnerability
Vibration-induced illusion of movement is hindered by acute stroke but mostly by aging: a cross-sectional study
No full textInternational audienceThe proprioceptive and visual systems play a major role in daily tasks by providing continuous feedback to the central nervous system (CNS) for coordinating movements. However, it remains unclear to what extent alterations in the proprioceptive system and CNS affect vibration-induced illusion of movement (VIM) with age and after a stroke. To address this, 29 young (26 ± 7 years), 30 older (63 ± 8 years), and 26 stroke participants (68 ± 12 years) with left arm impairment, all right-handed, received triceps brachii tendon vibration with or without visual feedback of the vibrated arm (with/without vision), as it can modulate the illusion of movement. Vibrations were applied bilaterally in healthy participants and on the impaired left arm in stroke individuals. The illusion was quantified using the Standardized Kinesthetic Illusion Procedure (SKIP) ordinal scale, which evaluates the clearness and the direction of the movement, resulting in a total score on four. While young and older adults achieved higher scores without vision, acute stroke participants did not (Young left : µ (without/with) = 2.62/0.86, p < 0.001, Young right : µ (without/with) = 2.35/0.69, p < 0.001; Older left : µ (without/with) = 1.52/0.63, p < 0.001, Older right : µ (without/with) = 1.03/0.50, p < 0.01; Stroke: µ (without/with) = 0.85/0.62, p = 0.23). Moreover, young participants reported a stronger illusion than both older and acute stroke participants, and older participants reported a stronger illusion than acute stroke participants. Altogether, these findings suggest that aging alters VIM response, with acute stroke exacerbating this impairment. Finally, in acute stroke participants, a significant negative correlation between age and SKIP total score without vision was observed, highlighting the considerable impact of aging even within a pathological condition.</div
Experimental investigation on the influence of rice straw characteristics on the hygric, thermal and mechanical properties of straw-lime concretes
No full textInternational audienceThe utilization of agricultural wastes in the construction sector has experienced impressive expansion due to the growing awareness of climate change. These materials provide a fascinating solution to reduce the energy demand and consequential carbon emissions, thanks to their attractive thermal, hygroscopic and environmental properties. In this context, the present study examines the impact of the characteristics of rice straw particles on the mechanical, hygric and thermal properties of straw concretes. The characterization of the concretes is mainly based on measurements of thermal conductivity, water vapor permeability, moisture buffering capacity, and mechanical properties. Several formulations are defined and tested by varying the type of straw particles and their sampling area on the stem. First, the impact of grinding process of rice straw on concretes incorporating these particles was evaluated. A comparison was made between concretes containing cut particles in the longitudinal direction with a tubular shape with concretes containing milled particles (flatter shape) of similar length. Then, the dependence of the physical and chemical properties of straw particles on their shape and sampling area on the stem is identified. The results showed that the properties of concretes are highly dependent on the shape and sampling area of straw particles. The dependence of the mechanical, thermal and hygric performances of concretes on the particles shape appears to be the most relevant parameter, while the variation in concrete performances based on sampling area is limited. Additionally, the results show that cut particles induce lighter and porous concretes compared to milled particles, leading to an attractive thermal conductivity, moisture buffering capacity and water vapor permeability, while decreasing the mechanical properties of concretes. It is also highlighted that particles extracted from the bottom of the stem exhibit excellent hygric properties, higher deformation capacity and lower thermal conductivity than particles from the top of the stem
Towards Participatory Monitoring of Global Changes at a Local Scale: Challenging the Contribution of Living Labs
No full textInternational audienceAssessing the local scale effects of global changes and share related knowledge with the population may bea key to rural society robustness in the Anthropocene. In line with transdisciplinarity trend, one approachaims to refine knowledge of global change impacts by integrating vernacular knowledge and local observa-tions. However, bridging the gap between theory and practice remains a significant challenge. Living labsare emerging in many regions as a science-society dialogue tool, enabling participatory data collection at alocal scale and analysis that combines scientific knowledge with vernacular expertise.We present experiments from a living-lab in the Cévennes, a Mediterranean mountain rural region in southFrance. Its climate is characterised by summer droughts and a high precipitation variability. Small hy-draulic heritage punctuates the watersheds, reflecting the populations’ adaptation to this variability and thedevelopment of deep vernacular hydrological knowledge. Nowadays, climate change combined to societalmutations (mains water usages and tourism development especially) induces an increasing water scarcity.The region has experimented water scarcity crises in 2017, 2021 and 2022, making hydrology a major localconcern. In this context, the living lab fosters the creation and animation of a inhabitants/scientists coop-eration to propose and experiment water management adapted to the local context.At the current state of this living-lab, the co-collection of data is effective through participatory mappingand participative observation procedure of water flows and biochemistry. This could lead to high resolutiondatabase. However, many questions remain regarding the participatory monitoring that could guaranteelong-term monitoring of relevant and reliable indicators of local-scale effects of global change: Are scientifi-cally relevant indicators the same as those of interest to local inhabitants? How can they be engaged overtime? What measurement tools should be implemented? How should this data be shared? Based on theexperience of this living lab, we will present our results and questioning about the participatory approachesfor global changes monitoring at a local scale and about the inhabitants/critical-zone scientists cooperation
Digital Thread based federated interoperability approach for DT engineering
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Étude des propriétés thermiques des écorces de pin maritime, robinier, bouleau
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Renewable Energy Mix System Modelling with Power Grid Integration: Methods, Approach and Challenges
No full textInternational audienceRenewable energy mix systems (RES) are crucial for sustainable energy transitions, but their integration with power grids poses technical, economic, and regulatory challenges. This paper addresses the critical challenges and methodologies associated with modeling RES integrated with power grids, essential for the global transition to sustainable energy. It examines the complexities of integrating variable renewable sources like wind and solar, highlighting technical, financial, environmental, and regulatory barriers through a comprehensive literature review. To overcome these obstacles, a decision centric framework is proposed, utilizing a Global Information System (GIS) based approach to optimize site selection, energy mix, and grid stability. This framework employs machine learning for enhanced grid feasibility assessments along with contingency analysis, incorporating predictive maintenance and demand supply balancing, alongside detailed simulations using tools like DigSILENT PowerFactory and Any-Logic. The methodology culminates in a decisional model that balances technical, economic, and environmental factors, ensuring the development of robust and efficient renewable energy systems
fNIRS reproducibility varies with data quality, analysis pipelines, and researcher experience
No full textInternational audienceAbstract As data analysis pipelines grow more complex in brain imaging research, understanding how methodological choices affect results is essential for ensuring reproducibility and transparency. This is especially relevant for functional Near-Infrared Spectroscopy (fNIRS), a rapidly growing technique for assessing brain function in naturalistic settings and across the lifespan, yet one that still lacks standardized analysis approaches. In the fNIRS Reproducibility Study Hub (FRESH) initiative, we asked 38 research teams worldwide to independently analyze the same two fNIRS datasets. Despite using different pipelines, nearly 80% of teams agreed on group-level results, particularly when hypotheses were strongly supported by literature. Teams with higher self-reported analysis confidence, which correlated with years of fNIRS experience, showed greater agreement. At the individual level, agreement was lower but improved with better data quality. The main sources of variability were related to how poor-quality data were handled, how responses were modeled, and how statistical analyses were conducted. These findings suggest that while flexible analytical tools are valuable, clearer methodological and reporting standards could greatly enhance reproducibility. By identifying key drivers of variability, this study highlights current challenges and offers direction for improving transparency and reliability in fNIRS research
Real-Time Estimation of Muscular Efficiency in Cyclists Using Garmin Devices
No full textInternational audienceMuscular efficiency—the ratio of mechanical power output to metabolic energy expenditure—is a key determinant of cycling performance. While traditionally assessed in laboratory settings, such methods are ill-suited for real-world conditions. This study introduces a field-deployable metric for real-time estimation of muscular efficiency using consumer-grade Garmin devices equipped with heart rate (HR) monitors and power meters. Efficiency is computed as the ratio of mechanical energy (power × time) to HR-derived metabolic energy, adjusted for individual characteristics (age, mass, sex) using validated predictive models (Keytel et al., 2005). Calculations are constrained to moderate intensities (between ventilatory threshold 1 and lactate threshold), where HR and power exhibit a linear relationship. Implemented as a Connect IQ data field, the metric was validated using Strava data from professional cyclists and tested over tens of thousands of kilometers in real-world conditions. Results show that intra-session efficiency trends reliably reflect physiological states—declining efficiency signals fatigue, while rising efficiency indicates optimal pacing. Although absolute values are influenced by environmental factors (e.g., temperature, altitude), relative trends remain actionable for in-ride decision-making. Despite limitations in the Garmin SDK (e.g., poor documentation, lack of formal verification tools), the implementation proved robust. The approach offers a practical, integrated alternative to existing tools that merely visualize HR and power without quantifying efficiency