Scientific Publications of the University of Toulouse II Le Mirail
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Positive to negative photoconductance switching in plasmonic gold nanoparticle networks
No full textInternational audienceThe elaboration of versatile materials in which electrical conduction is tuned by light irradiation is of paramount relevance to such diverse applications as photodetectors, photodiodes, solar cells or light sensors. Although positive photoconductance is increasingly common, systems with negative photoconductance are scarcely reported. In this work, a switching from positive to negative photoconductance is observed upon simple annealing of well-organized networks of gold nanoparticles stabilized by dodecanethiols. The photoconductance properties are investigated experimentally using impedance spectroscopy. The measured Nyquist plots and resonance curves of the impedance are analyzed in terms of equivalent electrical circuits consisting in parallel resistance, capacitance and photoconductance. The positive and negative photo-current conversion efficiencies of the nanoparticles network are estimated k PPC = 389 ± 40 nS.W -1 .cm 2 and k NPC = -241 ± 40 nS.W -1 .cm 2 , respectively. With the aid of density functional theory calculations, the origin of the photoconductance is discussed, at the nanoscale level, in terms of changes of molecular conformation. Such molecular effects assist charge carrier tunneling between first neighbor nanoparticles, and favor the formation of traps introduced by the annealing of the sample. The present work contributes to the understanding of plasmo-electronic properties of hybrid molecule-nanoparticle self-assembled nano-structures
Efficient Memory Usage For Edge FaaS Platforms
No full textInternational audienceFunction as a Service (FaaS) is a great fit for data and event processing in Edge environments. These environments are characterized by resource-constrained devices that require efficient memory usage optimizations. Existing optimization so- lutions for memory in high-end clusters such as data centers cannot be used in Edge environments because they either depend on unavailable hardware features such as RDMA or require resource-intensive analysis such as periodic memory scanning, compression, or decompression. In this paper, we introduce Extensible RUNtimes (ERUN), a lightweight mechanism for existing FaaS runtimes aimed at optimizing memory utilization by reducing the memory usage of idle sandboxes (i.e., those awaiting function execution). ERUN operates through two main actions: Shrink and Expand. The Shrink operation unloads libraries and reclaims memory from the sandboxes, while the Expand operation quickly reloads the libraries when a function is executed. The Expand operation leverages an in-memory store that maintains a single instance of discarded libraries on the node. We implement the ERUN mechanism, which can be applied to any runtime environment, in a Python runtime. We extensively evaluated our prototype in a 10-node Edge cluster using 10 popular FaaS functions. The results show that ERUN can reduce idle sandbox memory usage by up to 23.13× and improve the warm-start ratio by 1.38×, while incurring less than 2% overhead on function execution time and energy usage
La mobilité durant la vie et les fonctionnements sociaux des premiers agropasteurs du Néolithique à partir des isotopes de l’oxygène et du strontium
No full textInternational audienceLe développement d’études pluridisciplinaires croisant données biochimiques et génétiques a démontré que les fonctionnements de certains groupes néolithiques étaient fortement liés au sexe des individus au travers de mobilités spécifiques pour les femmes, de patrilinéarités dans les recrutements des ensembles funéraires et de possibles fonctionnements patrilocaux. Dans la continuité de ces travaux, le projet WomenSOFar (ANR-21-CE03-0008) explore les différences liées au sexe et aux moments de la vie dans les organisations sociales des premiers groupes d’agropasteurs d’Europe de l’Ouest et d’Afrique du Nord.En nous appuyant sur un corpus de 155 échantillonnages réalisés sur l’émail de molaires, nous avons étudié les variations dans les signaux isotopiques (87Sr/86Sr, δ18O) au cours de la période de formation des couronnes dentaires de 74 individus datés du Néolithique moyen (4500-3300 BCE) provenant du Bassin Parisien, du Massif Central, de la Vallée du Rhône et de la Côte Méditerranéenne. Nous avons comparé ces variations à des référentiels publiés et inédits sur les isotopes biodisponibles localement. Nous avons employé des modélisations statistiques pour caractériser les mobilités au cours de la vie et les différences dans les histoires de vie entre les femmes et les hommes.Les résultats montrent une importante variation des rapports isotopiques principalement pour des sujets féminins, et de façon plus prononcée sur la côte méditerranéenne. Des changements d’environnement peuvent avoir lieu durant l’enfance et l’adolescence, soulignant l’importance de la relation entre âge et statut social. L’emploi de mesures multiples par individus montre des trajectoires individuelles variées : certains individus se déplacent vers de nouveaux environnements, d’autres semblent quitter puis revenir dans les environnements de leur enfance. Ces données mettent en évidence l’importance des histoires individuelles ainsi que des identités biologiques et sociales dans les fonctionnements des groupes étudiés
On the relaxation towards mechanical equilibrium for two-pressure compressible flows
No full textWe introduce a symmetrization of a one-velocity two-pressures Baer-Nunziato type model for mixtures of barotropic compressible fluids. It allows us to justify the zero compaction viscosity limit and to recover a solution of the so-called Kapila model. On the other hand, the symmetrization highlights a pressure-induced stabilization mechanism which allows us to recover a global-in-time existence result for initial data close to constant states
Sur les traces des « collèges invisibles »: Création et analyse de réseaux scientifiques
No full textMasterAtelier de formation URFIST Occitanie sur l'analyse de citations
Motor complications and postural abnormalities interplay in Parkinson's disease
No full textInternational audienceBackground: Postural abnormalities (PA) and motor complications (MCs, including motor fluctuations - MFs- and levodopa-induced dyskinesia - LIDs) are hallmark of Parkinson's disease (PD) progression, yet their relationship remains poorly understood.Objective: To investigate the association between PA and MCs, motor symptoms, and non-motor symptoms (NMS) in patients with PD, and to assess whether PA influences the development of MCs over time.Methods: Data of the prospective NS-Park cohort (27 French PD Expert Centers) were analysed. PA was defined by a score ≥2 on item 3.13 of the MDS-UPDRS-III. Associations between PA and MCs, as well as with other motor symptoms and NMS, were assessed using logistic regression models. We used interval censoring survival models to assess the associations between PA at inclusion and the incidence of MCs. Analyses were adjusted for sex, age, disease duration, dopaminergic dose, and disease severity.Results: Among 13,037 included PD patients (58.7 % male, median age at diagnosis 61 years), 724 (5.6 %) presented with PA. Patients with PA had longer disease duration, higher disease severity, and higher dopaminergic treatment. PA exhibited a higher prevalence of troublesome MFs (OR: 5.96; 95 % CI: 4.25-8.32) and LIDs (OR: 2.81; 95 % CI: 1.79-4.30), while associations with milder MCs were inconsistent. However, PA was not significantly associated with the development of MCs during follow-up.Conclusions: PA are associated with more frequent severe MCs, and a higher burden of motor and NMS, making patient care particularly challenging
Produire, échanger, transmettre le savoir : pratiques et usages chez les mathématiciennes françaises au XXe siècle
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Expériences fraternelles d’adolescents identifiés HPI
No full textInternational audienceObjectives: This article seeks to enhance the understanding of sibling experiences of adolescents identified as gifted and to explore the perceived effects of this label on the sibling dynamic. These experiences are understudied; existing research is occasionally outdated, and, to our knowledge, no study has been carried out in France. However, these relationships are central to social development as they allow for the learning of social relations.Method: This article presents the results of a qualitative study of 27 gifted adolescents aged 10 to 15, recruited in France via semi-structured interviews after obtaining written consent from both parents and adolescents. A thematic content analysis was performed using N’Vivo software, guided by a framework inspired by the classic dimensions of sibling relationships (warmth, opposition, identification).Results: Sibling experiences appeared ambivalent, blending warmth (sharing, mutual aid, closeness) and opposition (conflicts, sometimes playful violence, antagonism), while remaining globally satisfactory. Identification and differentiation processes occurred simultaneously. The gifted label was not considered decisive; perceived effects were most notable when the label was shared among siblings.Discussion: The findings suggest that a sibling who is gifted can be a relational resource and an asset for socialization, without overestimating the role of the label in light of ordinary sibling dynamics.Conclusions: The sibling experiences of adolescents identified as gifted are marked by normative ambivalence and identity processes, with the label playing a secondary role unless it creates a shared norm within the sibling group.Objectifs. Cet article souhaite contribuer à une meilleure compréhension des expériences fraternelles d’adolescents identifiés à haut potentiel intellectuel (HPI) et interroger les effets perçus de cette étiquette dans la fratrie. Ces expériences sont peu étudiées, les recherches sont parfois anciennes et, à notre connaissance, aucune n’a été conduite en France. Pourtant, ces relations sont centrales dans le développement social puisqu’elles permettent de faire l’apprentissage des rapports sociaux. Méthode. Cet article présente les résultats d’une étude qualitative menée auprès de 27 adolescents HPI âgés de 10 à 15 ans, recrutés en France, via des entretiens semi-directifs, après l’obtention du consentement écrit des parents et des adolescents. Une analyse de contenu thématique assistée par le logiciel N’Vivo a été conduite, à partir d’une grille inspirée des dimensions classiques des relations fraternelles (chaleur, opposition, identification). Résultats. Les expériences fraternelles apparaissent ambivalentes, conjuguant chaleur (partage, entraide, proximité) et opposition (conflits, violences parfois ludiques, antagonisme), tout en restant globalement satisfaisantes. Des processus d’identification et de différenciation coexistent. L’étiquette de HPI n’est pas jugée déterminante ; des effets perçus sont surtout rapportés lorsque cette caractéristique est partagée au sein de la fratrie. Discussion. Les résultats plaident pour considérer le frère ou la sœur également identifié(e) HPI comme une ressource relationnelle et un appui de socialisation, sans surestimer le rôle de l’étiquette au regard des dynamiques fraternelles ordinaires. Conclusions. Les expériences fraternelles d’adolescents identifiés HPI sont marquées par une ambivalence normative et des enjeux identitaires, l’étiquette jouant un rôle secondaire sauf lorsqu’elle fonde une norme partagée dans la fratrie
Monogamy of Highly Symmetric States
No full textInternational audienceWe investigate the extent to which two particles can be maximally entangled when they are also similarly entangled with other particles on a complete graph, focusing on Werner, isotropic, and Brauer states. To address this, we formulate and solve optimization problems that draw on concepts from many-body physics, computational complexity, and quantum cryptography. We approach the problem by formalizing it as a semi-definite program (SDP), which we solve analytically using tools from representation theory. Notably, we determine the exact maximum values for the projection onto the maximally entangled state and the antisymmetric Werner state, thereby resolving long-standing open problems in the field of quantum extendibility. Our results are achieved by leveraging SDP duality, the representation theory of symmetric, unitary and orthogonal groups, and the Brauer algebra
Collaborative Action on Timing InterferenCes: Summary and Perspectives at Mid-term
No full textInternational audienceCAOTIC is an ambitious initiative aimed at pooling and coordinating the efforts of major French research teams working on timing analysis of multicore real-time systems, with a focus on interference due to shared resources. The objective is to enable the efficient use of multicores in critical systems. Based on a better understanding of timing anomalies and interference, considering the specificities of applications (structural properties and execution model), and revisiting the links between timing analysis and synthesis processes (code generation, mapping, scheduling), we target significant progresses in timing analysis models and techniques for critical systems, as well as in methodologies for their application in industry. In this paper, at project mid-term, we show the progress of the project. We also present some original work, about the use of a Tricore plaform and its timing model, and discuss open questions and future work