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Bug dans plusieurs solveurs de programmation linéaire en nombres entiers
No full textNational audienceLa programmation linéaire en nombre entiers (PLNE) est de plus en plus utilisée au-delà de la communauté de Recherche Opérationnelle. Des chercheurs et chercheuses en conception matérielle ou en biologie se sont notamment emparé·e·s de ces outils pour leurs applications. Les solveurs de PLNE sont ainsi souvent utilisés comme des boîtes noires, sans connaissances particulières quant à leur fonctionnement interne ou de leurs nombreux paramètres.Avec cette présentation nous discutons des bugs potentiels que les utilisateurs et utilisatrices de solveurs peuvent rencontrer. Nous montrons avec l'exemple d'un modèle produit par CarveMe que certains bugs se produisent et peuvent passer inaperçus. Nous tentons ensuite d'en comprendre l'origine sans entrer dans le solveur et d'en éviter la survenue depuis l'étape de modélisation et paramétrage du solveur
Weinstein exactness of nearby Lagrangians and related questions
No full textWe address the following problem: if a Hamiltonian diffeomorphism maps a Lagrangian submanifold L to a small Weinstein neighborhood of L, is the image necessarily Hamiltonian isotopic to L inside that neighborhood? On the one hand, we show that the question can have a negative answer in any symplectic manifold of dimension at least six. On the other hand, we answer an a priori weaker form of the question in the positive in various cases when L satisfies a rationality condition: we prove that the image of L is often exact inside the Weinstein neighborhood. We provide applications to the Lagrangian counterpart of the C^0 flux conjecture, to C^0-rigidity phenomena of Hamiltonian diffeomorphisms, and to topological properties of spaces of Lagrangians with the same rationality constraint. Moreover, we state and prove cases of an analogue of Viterbo's spectral norm conjecture for non-exact Lagrangians; in the process, we make progress on an old question of Viterbo regarding integer difference vectors between points of Lagrangians
Modeling and Parameter Estimation of Tumor Spheroids from Bottom-View Imaging: Beyond the Spherical Assumption
No full textTumor spheroids are widely used in vitro models for studying tumor growth and treatment response, yet their analysis is often limited by incomplete geometric measurements. In practice, only a two-dimensional bottom view is available, which can lead to strong biases when spheroids deviate from an ideal spherical shape, in particular for flattened aggregates. We propose a mechanistic modeling and data assimilation framework that accounts for both poor data quality and model uncertainty. A biologically motivated partial differential equations model with axial symmetry is introduced and reduced to a low-dimensional system compatible with sparse observations and ellipsoidal shapes. Uncertainties in initial conditions and parameters are handled using a Luenberger-type observer coupled with a reduced-order unscented Kalman filter. The approach is validated on synthetic data and applied to experimental in vitro spheroid data under propranolol treatment, illustrating how model-based integration of limited measurements improves the interpretation of spheroid growth dynamics and treatment-induced morphological changes
Certifying the Decidability of the Word Problem in Monoids at Large
No full textInternational audienceWhile the word problem for monoids is undecidable in general, having a decision procedure for some finitely presented monoid of interest has numerous applications. This paper presents a toolbox for the Rocq proof assistant that can be used to verify the decidability of the word problem for a given monoid and, in some cases, to produce the corresponding decision procedure. As this verification can be computationally intensive, the toolbox heavily relies on proofs by reflection guided by an external oracle. This approach has been successfully used on several large presentations from the literature, as well as on a database of one million 1-relation monoids.The huge size of this database forced some unusual considerations onto the Rocq formalization, so that the formal proofs could be checked in a reasonable amount of time.</p
Integrating functional accessibility and pedestrian environmental comfort: A spatially explicit framework for urban walkability evaluation
No full textInternational audienceUrban walkability is central to sustainable urban development and, at the city scale, is increasingly viewed as shaped by both functional accessibility and pedestrian environmental comfort (PEC). However, most citywide assessments remain predominantly function-oriented, and few provide explicit behavioral validation using observed walking patterns. This study addresses this gap by proposing a spatially explicit, dual-dimensional framework that treats functional accessibility and PEC as co-equal components of walkability. Using Nantes, France, as a case study, we implement the framework on a uniform 150 m × 150 m grid and derive three composite indices—Traditional Walkability Score (TWS), a PEC index, and a PEC-enhanced Walkability Score (PEWS)—from GIS indicators standardized and combined using entropy-based weighting. Our analysis reveals a systematic spatial mismatch between functional and environmental dimensions: TWS concentrates in amenity-rich and well-connected areas, whereas PEC is highest along blue–green corridors. The integrated PEWS induces a targeted spatial re-ranking, deprioritizing functionally rich but environmentally harsh central areas while upgrading nature-rich peripheral zones. We then behaviorally validate the framework using observed pedestrian counts and gridded resident population data from INSEE, operationalized as a deviation metric comparing observed flows with population-based expectations. Blue–green features (trees, rivers, and green spaces) are associated with higher-than-expected pedestrian activity, whereas proximity to major motorized roads is associated with lower-than-expected activity. These findings support PEC as a necessary component of city-scale walkability assessment and provide actionable guidance for planning interventions
Investigations of raster layup effect on mechanical and fracture properties of material extruded ABS samples under biaxial loadings
No full textInternational audienceThe mechanical properties of 3D printed parts are influenced by the parameters used during the manufacturing process. Among them, the raster orientation plays an important role. In this study, biaxial tensile tests coupled with digital image correlation are used to evaluate the effect of raster orientation on the deformation and failure mechanisms of acrylonitrile butadiene styrene samples. It is shown that the local deformation mechanisms are mainly driven by the raster orientation after the crack initiation at sample corners. The kinematic fields evidence that the local deformation mechanisms are related to the mesostructures induced by the fabrication process. A comparative analysis of the different printing orientations (0°/90°, ±45°, 15°/105°, and 30°/120°) reveals that the orthotropic architecture strongly influences the mechanical response and failure mechanisms. This study points out the necessity of improving the filament junctions of polymer parts obtained by fused filament fabrication
Exploring processability limitations of commercial hard carbon for negative electrodes of Na-ion batteries
No full textInternational audienceOptimizing electrode manufacturing processes for sodium-ion batteries (SIBs) is crucial for enhancing their performance and commercial viability. This study systematically investigates the influence of critical electrode fabrication parameters, including solid content, mass loading, and calendering, on commercial hard carbon (HC) electrode properties. Slurries prepared with 35 % and 40 % solid content (SC) demonstrated distinct rheological behaviours, directly affecting electrode mechanical stability and processability. The slurry with SC-35 % provided a better balance between manageable viscosity and robust mechanical stability upon drying, whereas SC40 % slurry exhibited higher viscosity, particle agglomeration, and poorer electrode mechanical integrity. Calendering was studied at compression degrees of 10 %, 20 %, and 30 %, revealing limited effectiveness in reducing porosity due to the intrinsic mechanical properties of HC, whereas, higher compression degrees led to structural damage. Electrochemical studies conducted in half-cells (HC vs. Na) and full-cells (HC vs. Na3V2(PO4)3) clearly indicated better electrochemical performance at moderate calendering degrees (10-20 %), effectively balancing mechanical integrity and electrical conductivity. This comprehensive study results in a useful experimental database in academic literature, underscoring the importance of precise control over slurry formulation and calendering parameters to achieve structurally robust electrodes, thus significantly enhancing the practical performance of SIBs
Communal coping in high-level sports teams: A mixed-method investigation
No full textInternational audienceCommunal coping, defined as collectively perceiving and addressing stressors as "our problem," plays a critical role in teams’ ability to manage stressful situations. By using a mixed-method approach this study examined (1) the extent to which athletes share their appraisals of stressful match situations, (2) the degree to which they perceive coping strategies as collectively enacted, and (3) psychosocial and contextual factors that may facilitate or hinder these shared processes. Forty-nine elite athletes from four high-level sports teams (basketball, football, and ice hockey) participated in this study. Quantitative data were analyzed using descriptive statistics, whereas qualitative data from the focus groups were analyzed using thematic analysis. The quantitative results indicated variability in athletes' shared appraisals of stress intensity and revealed differential use of communal coping strategies across teams and situations. Focus groups provided in-depth qualitative insights into the factors that influenced these processes. The findings highlight that communal coping is a complex social phenomenon influenced by communication, leadership, emotional expression, and environmental contexts such as competition stakes and timing. This study underscores the necessity for mixed methods approaches in future communal coping research, especially in ecological settings, emphasizing both shared appraisal and communal action dimensions. Recommendations for future research include employing larger samples, evaluating both primary and secondary appraisals, and explicitly examining perceptions of stress ownership to enhance understanding of communal coping among sports team
"Multi-scale climate analysis of two coastal wine terroirs in Uruguay: Adapting to climate change and heatwaves"
No full textInternational audienc
Therapeutic efficacy of in-vivo IL-12 plasmid delivery using microbubble-assisted ultrasound in a B16F10 mouse melanoma model: A proof of concept
No full textInternational audienceIn-vivo targeted delivery of immunostimulatory molecules for melanoma treatment is a promising strategy to overcome complexity, toxicity, and cost associated with current immunotherapies. Among these molecules, interleukine-12 (IL-12) is a potent immunostimulatory cytokine that plays a major role in antitumoral immune response. However, systemic administration of IL-12 induces severe side effects, highlighting the need for efficient and safe in-vivo delivery modalities. Microbubble-assisted ultrasound (MB-assisted US) is an emerging non-invasive and targeted method for therapeutic molecule delivery. This study aimed to evaluate its efficacy for intratumoral (i.t.) delivery of a plasmid encoding IL-12 (pIL-12) in a mouse melanoma model. In-vitro, delivery of 5 or 10 g of pIL-12 into melanoma cell suspensions using MB-assisted US increased IL-12 concentration to 1429 ± 125 and 2352 ± 125 pg/mL, respectively, whereas pIL-12 treatment alone did not elicit IL-12 secretion. Similarly, acoustically mediated delivery of 10 or 50 g of pIL-12 into melanoma spheroids significantly increased IL-12 concentration - 131 ± 7 and 250 ± 60 pg/mL respectively - compared to pIL-12 alone (0 pg/mL for 10 g and 7.5 ± 7.5 pg/mL for 50 g). In-vivo, acoustically mediated pIL-12 delivery increased serum mIL-12 concentration by 5-fold compared with i.t. pIL-12 injection alone, promoting NK cell recruitment and activation within the tumor microenvironment. By day 15, this strategy reduced tumor volume by 2.5-fold relative to i.t. pIL-12 alone and improved mouse health status. These findings confirm that MB-assisted US is a relevant modality for in-vivo delivery of immunostimulatory molecules in melanoma therapy