Scientific Publications of the University of Toulouse II Le Mirail
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L'Importance Marginale des Distorsions et de l'Alignement dans les Systèmes CASSI
No full textInternational audienceCoded Aperture Snapshot Spectral Imagers (CASSI) are designed to acquire 2D coded acquisitions of hyperspectral scenes (HSS). Associated with reconstruction algorithms, they allow to analyze the HSS using a small amount of data. Various configurations of such imagers exist, with different distortions. In this article we show that reconstruction quality is relatively insensitive to these distortions, if modeled correctly. To this end, we introduce a differentiable ray-tracing-based model that incorporates aberrations and distortions to render realistic coded hyperspectral acquisitions using CASSI. Such simulated acquisitions are used to train state-of-the-art hyperspectral cube reconstruction algorithms. We also adapted these algorithms through the use of a ray-tracing-based mapping function which accounts for aberrations and distortions. We evaluated four comparable CASSI systems with varying degree of optical aberrations and misalignments, using five state-of-the-art hyperspectral cube reconstruction algorithms. Our analyses show that if properly modeled, the effects of geometric distortions of the system and misalignment of the dispersive elements have a marginal impact on the overall reconstruction quality. Therefore, relaxing traditional constraints on measurement conformity and fidelity to the scene enables the development of novel imaging instruments, guided by performance metrics applied to the design or the processing of acquisitions. By providing a complete framework for design, simulation and evaluation, this work contributes to the optimization and exploration of new CASSI systems and more generally to the computational imaging community.Les imageurs spectraux à ouverture codée (CASSI) sont conçus pour réaliser des acquisitions codées en 2D de scènes hyperspectrales. Associés à des algorithmes de reconstruction, ils permettent d'analyser la scène hyperspectrale en utilisant une faible quantité de données. Il existe différentes configurations de ces imageurs, avec différentes distorsions. Dans cet article, nous montrons que la qualité de la reconstruction est relativement insensible à ces distorsions, si elles sont modélisées correctement. Nous introduisons un modèle différentiable basé sur le tracé de rayons qui incorpore les aberrations et les distorsions pour faire le rendu d'acquisitions hyperspectrales codées réalistes de systèmes CASSI. Ces acquisitions simulées sont utilisées pour entraîner des algorithmes de reconstruction de cubes hyperspectraux à l'état de l'art. Nous avons également adapté ces algorithmes en utilisant une fonction de mapping basée sur le tracé de rayons qui tient compte des aberrations et des distorsions. Nous avons évalué quatre systèmes CASSI comparables avec différents degrés d'aberrations et de désalignements optiques, en utilisant cinq algorithmes de reconstruction de cubes hyperspectraux à l'état de l'art. Nos analyses montrent que, s'ils sont correctement modélisés, les effets des distorsions géométriques du système et du désalignement des éléments dispersifs ont un impact marginal sur la qualité globale de la reconstruction. Par conséquent, l'assouplissement des contraintes traditionnelles en matière de conformité des mesures et de fidélité à la scène permet de développer de nouveaux instruments d'imagerie, guidés par des mesures de performance appliquées à la conception ou au traitement des acquisitions. En fournissant un ensemble complet pour la conception, la simulation et l'évaluation, ce travail contribue à l'optimisation et à l'exploration de nouveaux systèmes CASSI et plus généralement à la communauté de l'imagerie computationnelle
Opportunities and Challenges towards Portable Nanotechnology Processes over Open Facilities
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Dans l'intimité de Sapiens. Vivre il y a 40 000 ans
No full textInternational audienceQui n'a pas rêvé de découvrir au plus près le quotidien de ses ancêtres ? Entre enquête scientifique et récit immersif, Nicolas Teyssandier nous entraîne dans l'intimité de ces groupes de chasseurs-cueilleurs nomades, qui -il y a quarante mille ans -sillonnaient les steppes durant la dernière période glaciaire dans le sillage des troupeaux de rennes, de chevaux et autres bisons. Il nous fait partager leur quotidien, leurs expéditions de chasse, en faisant renaître sous nos yeux leurs techniques de fabrication d'armes de chasse et d'outils les plus abouties. Loin de l'image caricaturale de peuples isolés luttant pour leur survie, en proie à un environnement hostile, errant sans cesse à la recherche de nourriture, les Sapiens du Paléolithique récent formaient des sociétés complexes, disposant de hauts niveaux de connaissances et de savoir-faire. Nicolas Teyssandier est préhistorien, directeur de recherche au CNRS et directeur adjoint du laboratoire TRACES, basé à l'université Toulouse-Jean-Jaurès. Il a coscénarisé et a été le conseiller scientifique du film documentaire "Le fils de Néandertal ou le secret de nos origines" (Arte, 2017). Il est notamment l'auteur de Nos premières fois (La ville brûle/Champs Flammarion)
Exploring the subject heterogeneity of scientific research projects funding-example of the Chinese natural science foundation
No full textIn the increasingly competitive landscape of science and technology funding, understanding the heterogeneous factors and outcomes in funding allocation is crucial. This study proposes a research framework of subject heterogeneity to explore how the individual and combined characteristics of scholars and research topics impact funding acquisition, intensity, and performance. We use the case of the National Natural Science Foundation of China (NSFC) funding for artificial intelligence projects from 2009 to 2018 to empirically validate our framework. The findings reveal that scholars affiliated with high-level institutions, who focus on specialized areas and produce high-quality representative work, are more likely to secure funding. Unexpectedly, funding incentives did not significantly alter scholars' enthusiasm for pursuing popular topics. Moreover, the results indicate that funding has a more substantial impact on cultivating scholars than on advancing new research topics, particularly in the short term. Expanding the scope of funding proves to be more effective in enhancing research performance than merely increasing funding intensity. These insights provide valuable guidance for researchers in topic selection and submission strategies, as well as for policymakers aiming to optimize the management of competitive scientific projects.</div
An interdisciplinary approach for air quality assessment : biomonitoring using Tillandsia bergeri and risk perceptions in the environmentally sacrified province of Chacabuco, Chile
No full textInternational audienceAwareness of air pollution and the associated environmental and health risks is growing world wide. In order to answer the socio-environmentalchallenges posed by climate change, natural resource degradation and industrialization, scientists are advocating more holistic research linking environmental quality and public health. However, few studies have managed to integrate local communities’ concerns and knowledge with easy-to-use biomonitoring systems to produce science that contextualises their environment risk. This case study was carried out in an “environmental sacrifice zone” located in the Chacabuco province (Chile), where there have been no prior air quality studies or monitoring despite local populations suspecting metallic contamination. An interdisciplinary approach was proposed to create an innovative air quality assessment, combining both social and geo-graphical data for risk perception and biomonitoring experiments with epiphyte plants (T. bergeri) in strategic sites. The cross-analysis of inhabitant interviews and cognitive maps shows that air pollution is perceived to be of greater risk in the northern and central part of the province. Microscopic and spectroscopic techniques highlight different origins of metal(loid)s in the air. Epiphyte plants reveal a site-dependent accumulation of pollutants (As, Cu, Cr, Mn, Pb, Ni, Zn). The collection of dust in Owen gauges and subsequent health risk assessment do not show evidence of hazard quotient or cancer risk. But enrichment factors and pollution indexes highlight that three sites can be classified as impacted, suggesting that more attention should be paid to chronic exposure and long-term environmental effects in this area. The social perception of air pollution appears to be correlated to the geochemical identification of some existing sources of metal(loid)s
Compte rendu de Marie-Céline Isaïa, Une autre histoire. Histoire, temps et passé dans les Vies et Passions latines (ive-xie siècle), Paris/Orléans, Institut de recherche et d’histoire des textes (« Bibliothèque d’histoire des textes »), 2023
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Dynamiques déterritorialisantes et transnationalisation du cinéma marocain. Etude de cas autour de Adam (M. Touzani) et Sofia (M. Ben'Mbarek)
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Pour une science de la Transition Énergétique au Service de la Société: Rapport du groupe interdisciplinaire ARPEGES CNRS pour la Transition énergétique
No full textNational audienceResearch on the energy transition raises a series of major challenges: it is a problem-oriented field of research (that of decarbonising the energy mix), which must be resolutely ethical and include principles of social and environmental justice from the very beginning... and this despite the problematic nature of the notion of transition which gives a misleading notion of the process that will lead to desired changes - if there are any. Taking this observation as its starting point, this paper sets out a number of avenues for research into key issues. It begins by examining the way in which the energy transition is transforming the interplay between actors in the energy sector and the scales at which decisions are taken and implemented. While inviting to take account of the wide variety of national contexts and levels of development, the article acknowledges the certainties and uncertainties surrounding the composition of the energy mix. It also stresses the importance of taking account of the externalities of technological choices, particularly in environmental terms. This enables us to draw up a research agenda focusing not only on the spatial aspects of transitions, but also on the ways in which economic models need to incorporate new parameters and new constraints. The article also invites to consider how the relationship between energy production and consumption is changing, and how consumption needs to be reduced. In so doing, the article defends the idea that research, which is necessarily interdisciplinary and reflexive, has a strong role to play in basing transition action on scientifically sound findings.La recherche sur la transition énergétique pose plusieurs défis de taille : c’est une recherche orientée problème (celui de la décarbonation du mix énergétique), qui doit être résolument éthique et intégrer dès sa formulation des principes de justice sociale et environnementale... et ce alors même que la notion de transition est problématique en ceci qu’elle donne une fausse idée du processus qui mènera aux changements attendus – si changements il y a. Partant de ce constat, ce Regard dresse des pistes de recherche sur des thématiques saillantes, notamment sur les acteurs et échelles des transitions, les techniques et leurs externalités, les modèles économiques et sociaux qui permettent de guider l’action, les modèles de consommation production et s’interroge sur les rapports entre consommation et production. Il défend in fine l’idée que la recherche, forcément interdisciplinaire et réflexive, a un rôle fort à jouer pour fonder l’action en matière de transition sur des constats scientifiquement fondés
Flames, fear and lies. How the emotional power of iconic fires such as those in Los Angeles in 2025 shapes collective memory and fuels misinformation.
No full textInternational audienceThe January 2025 Los Angeles wildfires precipitated not only unprecedented material destruction—claiming over 40,000 acres, 12,000 structures, and 24 lives—but also a parallel crisis of misinformation that exposed the complex interplay between environmental disasters, social inequality, and digital communication systems. This paper presents a comprehensive analysis of how the symbolic power of fire—rooted in deep cultural archetypes and collective memory—amplifies the creation and diffusion of misinformation during environmental crises, transforming localized disasters into global spectacles of contested meaning. Drawing on interdisciplinary theoretical frameworks including framing theory, social network analysis, rumor theory, and cultural memory studies, this research examines how media coverage, social media dynamics, and institutional responses shaped public discourse during the LA fires, revealing the mechanisms through which material threats become semiotic battlegrounds.Analysis of recent empirical evidence from comparable wildfire events—specifically the Australian Black Summer fires (2019–2020) and California wildfires (2018–2024)—demonstrates that misinformation campaigns are driven primarily by coordinated human networks exploiting emotional symbolism rather than automated bot activity. Network analyses reveal polarized community structures where "Supporter" groups promoting conspiratorial narratives engage primarily through aggressive hashtag activism and emotionally charged replies, while "Opposer" communities countering misinformation rely on retweeting authoritative sources. This asymmetrical engagement, compounded by platform affordances that algorithmically amplify emotionally arousing content regardless of veracity, creates information environments where sensational false claims systematically outperform measured factual corrections. The paper documents five dominant misinformation typologies during the LA fires: elite water hoarding conspiracy theories, politically motivated arson allegations, AI-generated imagery of destroyed landmarks, claims of preferential firefighting for wealthy neighborhoods, and insurance industry orchestration narratives. Each narrative activates preexisting cultural schemas about class privilege, institutional capture, and environmental injustice, making them psychologically compelling regardless of evidentiary support.Furthermore, the research demonstrates how media framing oscillates between climate attribution, sensationalized celebrity spectacle, and institutional accountability, with profound implications for public perception and policy outcomes. Celebrity-focused coverage, while humanizing the disaster, inadvertently reinforces perceptions of preferential treatment and elite insulation, particularly when contrasted with minimal coverage of working-class communities in the San Gabriel Valley. Climate attribution frames—emphasizing anthropogenic warming and drought intensification—compete with "delayist" counter-framing that acknowledges climate change while advocating for technological fixes or forest management solutions that implicitly defer emissions reductions. This climate delayism, we argue, functions as a form of emotional regulation that reduces eco-anxiety and climate grief at the cost of political mobilization, effectively neutralizing the policy window that disasters typically open. The concept of eco-anxiety—characterized by chronic climate distress, solastalgia, and pre-traumatic stress—emerges as both a rational response to escalating threats and a psychological vulnerability that misinformation exploits by offering simplistic causal explanations and moralistic narratives that restore a sense of agency and certainty.Fire's archetypal significance—as destroyer, purifier, transformer, and divine judge—makes it uniquely susceptible to conspiratorial interpretation and moral panic. Historical precedents from the Great Fire of Rome (64 CE) to Notre-Dame Cathedral (2019) demonstrate how fire events transcend material impact to become focal points for broader social anxieties about civilizational fragility, elite malfeasance, and cultural heritage loss. In Los Angeles, where the entertainment industry's global mythology intersects with stark socioeconomic stratification, fires expose the limitations of wealth as protection against climate impacts while activating deep-seated cultural schemas about environmental injustice and institutional betrayal. Preliminary evidence suggests that preexisting socioeconomic inequalities were both exposed and amplified through disaster narratives, with differential vulnerability manifesting across evacuation capacity, access to private firefighting services, water infrastructure reliability, and insurance coverage—patterns that fueled rumors of preferential resource allocation and institutional abandonment of marginalized communities.To address this dual crisis of environmental disaster and information disorder, the research proposes an integrated multi-level intervention framework. At the individual level, strategies include evidence-based media literacy education, psychological inoculation through "pre-bunking" of manipulation techniques, and emotional validation supports that acknowledge climate distress while providing agency-affirming action pathways. Network-level interventions focus on cultivating trusted messenger partnerships with community leaders and peer influencers, deploying coordinated counter-messaging campaigns, and engaging high-reach social media figures as information allies rather than adversaries. Platform-level reforms advocate for algorithmic adjustments that reduce amplification of demonstrably false content, introduction of friction mechanisms that prompt reflective sharing, and transparency tools that expose manipulation patterns. Institutional interventions emphasize proactive, transparent communication that fills information vacuums before rumors can colonize them, equity-centered resource allocation that addresses material grievances underlying distrust, and sustained community engagement that builds relationships before crises occur. Finally, culturally grounded interventions incorporate Indigenous knowledge systems and cultural burning practices that reframe fire relationships from adversarial to relational, develop narrative reframing strategies that acknowledge legitimate grievances while providing constructive alternatives, and support community-led commemorative practices that transform grief into collective resilience.This work contributes to disaster communication scholarship by integrating material and symbolic dimensions of fire, advancing theoretical understanding of how cultural schemas mediate misinformation susceptibility, and offering evidence-based strategies for building institutional trust and collective resilience in an era of escalating climate impacts. It challenges dominant narratives that attribute misinformation primarily to technological manipulation or foreign interference, instead demonstrating that the most potent drivers are culturally resonant narratives rooted in observable patterns of inequality and institutional failure. The research underscores that effective communication in disaster contexts requires not merely correcting false claims but addressing the structural conditions—material inequality, institutional opacity, algorithmic amplification, and emotional vulnerability—that make certain narratives psychologically compelling. As climate change intensifies and wildfire risks escalate, the patterns documented here will likely recur with increasing frequency, demanding comprehensive strategies that coordinate across individual, network, platform, institutional, and cultural levels to build communities resilient to both environmental disasters and the information disorders they precipitate
