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Detection and pre-localization of coastal wetlands in Brittany, France using topographical indices from altimetric and remote sensing data
No full textInternational audienceThe role of wetlands in coastal area processes must be recognized and strengthened. Unless the hydrological and related functions of coastal wetlands are maintained, the success of sustainable coastal development is uncertain. In this study, an initial methodology section is dedicated to the calculation and normalization of several topographic indices to assess soil moisture susceptibility in coastal wetland areas. By providing detailed information on the elevation and topographic structure of coastal wetlands, this study uses various topographic indices, including the Topographic Wetness Index (TWI), the Topographic Position Index (TPI), the Multi-Resolution Valley Bottom Flatness (MRVBF). Additionally, the study considers valley depth, which can contribute to a better understanding of hydrological dynamics, water level variations, and water flow zones during the process of mapping and monitoring changes in these environments. The second research aim of this work is evaluation of the pre-localization of potential coastal wetland areas and their evolution over time in relation to impervious surface changes in Brittany. The analysis reveals that between 1990 and 2020, the area of potentially impervious wetlands increased by 18.3% from 145.3 km 2 to 171.95 km 2 . By combining these pre-localization results with Corine Land Cover (CLC) data and OCS GE, the study highlights the influence of urbanized and impermeable area on coastal wetlands dynamics between 1990 and 2020. The third aim in of this article focuses on assessing the quality of the “binary classification” of wetlands and non-wetlands. A inventory focus on coastal wetlands (carried out by stakeholders between 2011 and 2019) is used as reference data to check whether the proposed methodology is effective and, if so, to determine the score at which it gives satisfactory results. Model performance metrics show a high recall of 0.948 for non-wetland areas, though with moderate precision (0.798), suggesting occasional misclassification of wetland areas as non-wetlands. For wetland areas, the approach achieved high precision (0.936) but a lower recall (0.759), indicating challenges in detecting all existing wetland areas. The overall accuracy of 0.854 and a Kappa coefficient of 0.708 point to a solid performance of the binary classification methodology
Psychometric properties of the Feeling of Unsafety Scale—Arabic in general population adults
No full textInternational audienceBackground Feelings of unsafety, including fear of crime, uncertainty, or insecurity, can negatively impact individuals by reducing psychological well-being and worsening health. Validating a simple and cost-effective tool to assess the general feeling of unsafety in the Arabic-speaking population, primarily residing in the Middle-East and North-Africa (MENA) region where safety can be a major concern, would be highly beneficial. The study aimed to translate the Feeling of Unsafety Scale into Arabic (FUSA) and evaluate its psychometric properties, including internal reliability, sex invariance, composite reliability, and correlation with a measure of intolerance of uncertainty. Methods A total of 484 Arabic-speaking adults was recruited between March and April 2024. A self-administered anonymous survey was distributed through social media using a Google Forms link. We used the FACTOR software to conduct the exploratory factor analysis (EFA) of the FUSA scale and RStudio for the confirmatory factor analysis (CFA). Results The confirmatory factor analysis of the unidimensional model was poor; the EFA conducted on the first split subsample showed a two-factor solution, with the CFA conducted on the second split subsample showing good fit. The latter model fit indices improved even more after adding a correlation between items 2–5 due to high modification indices. The reliability of the scale was excellent as shown by the McDonald’s omega and Cronbach’s alpha values for the total score ( ω = 0.89 and α = 0.90), Factor 1 = Feeling of outdoor unsafety (ω = 0.91 and α = 0.91) and Factor 2 = Feeling of indoor unsafety (ω = 0.83 and α = 0.83). Invariance was established between males and females. Good concurrent validity was attested by positive correlations between FUSA scores and intolerance of uncertainty dimensions. Conclusion The FUSA was found to be reliable, valid, and cost-effective for measuring the general feeling of unsafety in the general population. To evaluate its practical effectiveness and further enhance data on its construct validity, future studies should assess the scale in diverse contexts and among specific populations
Analog feedforward equalizer optimization in the context of 50G-PON
No full textInternational audienceWe address one of the challenges of 50 gigabit capable passive optical network (50G-PON) implementation induced by the limited bandwidth of low-cost components and signal distortions of fiber transmission and photonic devices. In the context of the broadband access network, and more specifically 50G-PON, the simplest and most affordable solution is usually the best. Implementing an analog feedforward equalizer (AFFE) is not as simple as using digital feedforward equalizer (DFFE) techniques but is relevant from a cost and energy consumption point of view. AFFE has a number of advantages, such as lower power consumption and lower latency, due to the fact that it avoids using an analog-to-digital converter (ADC). In this work, we focus on AFFE optimization techniques to mitigate intersymbol interference (ISI) and chromatic dispersion (CD) and therefore improve signal quality. We model an AFFE in order to reduce a complex problem (because of AFFE’s inter-cells non-uniformity and intra-cells non-linearity, for example) into a simpler formulation that can be solved according to a minimum mean square error (MMSE) approach. This approach is possible when the transmission channel does not fluctuate. Experimental validation through electrical and optical setups demonstrates the effectiveness of the proposed optimization, achieving a significant reduction in the bit error rate (BER) and opening eye diagrams for better signal clarity, thereby offering a viable solution for future optical networks
Subtle Changes at the RBD/hACE2 Interface During SARS-CoV-2 Variant Evolution: A Molecular Dynamics Study
No full textInternational audienceThe SARS-CoV-2 Omicron variants show different behavior compared to the previous variants, especially with respect to the Delta variant, which promotes a lower morbidity despite being much more contagious. In this perspective, we performed molecular dynamics (MD) simulations of the different spike RBD/hACE2 complexes corresponding to the WT, Delta and four Omicron variants. Carrying out a comprehensive analysis of residue interactions within and between the two partners allowed us to draw the profile of each variant by using complementary methods (PairInt, hydrophobic potential, contact PCA). PairInt calculations highlighted the residues most involved in electrostatic interactions, which make a strong contribution to the binding with highly stable interactions between spike RBD and hACE2. Apolar contacts made a substantial and complementary contribution in Omicron with the detection of two hydrophobic patches. Contact networks and cross-correlation matrices were able to detect subtle changes at point mutations as the S375F mutation occurring in all Omicron variants, which is likely to confer an advantage in binding stability. This study brings new highlights on the dynamic binding of spike RBD to hACE2, which may explain the final persistence of Omicron over Delta
La séquence organique de la vallée de l’Evel à Siviac (Evellys, Morbihan). Un jalon pour la compréhension des hydrosystèmes du Massif armoricain au début de l’Holocène
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Stoicism and the Tragedy of the Commons
No full textInternational audienceThis paper revisits the Tragedy of the Commons - a Pareto-dominated overuse of a common resource - through the lenses of Stoicism, and, in particular, of the Stoic discipline of desires, according to which one should wish for nothing that is not under one's control. Two economic accounts of the Stoic discipline of desires are explored: the I1 account (a requirement of indifference between outcomes differing only on things out of control) and the I2 account (requiring indifference between outcomes that are the best under each circumstance). When studying the implications of Stoicism for the outcome of an N-players simultaneous common pool resource game, it is shown that, under each of account of the Stoic discipline of desires, it is either the case that there is no overuse of the common resource at the symmetric Nash equilibrium, or the case that a suboptimal use of the common resource, if it occurs, is not seen as "tragic" at all
Du pâton d’argile au vase fini. Analyses technologiques de vases de stockage de l’âge du Fer du site gréco-indigène d’Incoronata
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Profils développementaux et orientation scolaire des enfants autistes après l'unité d'enseignement en maternelle,
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Exploring boundary conditions of sustained physical activity: implications for theory and practice.
No full textObjective: Sustained physical activity is crucial for health and is often referred to as 'physical activity maintenance.' However, this concept lacks consensus, possibly due limited study of the 'boundary conditions' under which this phenomenon occurs. This gap limits both theoretical development and interventional applications. This study examined the boundary conditions of two operational definitions of physical activity maintenance (activity threshold and timescale) and how their formulation impacts the detection of sustained physical activity phenomena. Methods: We analyzed 352 time series (length=182 days) of moderate-to-vigorous physical activity (MVPA) collected daily with Fitbit from participants in a weight loss intervention. Two activity thresholds were defined based on participants’ baseline intentions and physical activity levels: a) 150 minutes of MVPA/week for participants below this threshold at baseline (subsample BL-Inactive; n=101), and b) current level of MVPA/week for those exceeding 150 minutes of MVPA/week at baseline (subsample BL-Active; n=251). Regression trees were used to examine changes in physical activity trajectories using different boundary definitions of timescales (7, 14, 28, and 56 days). Results: At finer-grained timescales (7 days), physical activity exhibited repeated fluctuations, with sustained activity patterns in 27% of BL-Inactive and 5% of BL-Active participants. At coarser-grained timescales (56 days), activity trajectories were more stable, with sustained activity percentages increasing to 71% and 26%. Conclusions: Varying boundary conditions reveal different ways of conceptualizing sustained physical activity phenomena, leading to plausibly distinct conclusions about behavioral maintenance. These results highlight the importance of carefully studying boundary conditions as critical for robust theory and practice development
Critical Buckling Investigation of Composite Beams Under Poisson's Effect Using Nonlocal and Higher-order Shear Deformation Theories
No full textInternational audienceThis investigation addresses the study of the buckling of composite material beams with different stacking sequences using nonlocal theory. A rotational field was introduced along the width of the beam, considering Poisson's effect and higher-order transverse shear deformation theories with a new warping shape function. The equilibrium equations are derived analytically using the energy principle, and the numerical solution of these equations is based on energy minimization using the Ritz method. A comparative study with different higher-order deformation theories was conducted to calculate the dimensionless critical buckling of a symmetrically and asymmetrically cross-ply laminated composite beam for two types of materials. To examine the influence of the nonlocal effect on critical buckling, another study was carried out on an isotropic material beam using nonlocal theory for different slenderness ratios. The dimensionless critical buckling results show perfect agreement with and without nonlocal theory compared to previously available works in the literature. A detailed investigation of Poisson's effect on critical buckling demonstrated its significant influence in the case of short beams made of unidirectional composites and laminated composites with different fiber orientations