Scientific Publications of the University of Toulouse II Le Mirail
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Énergies d'interaction dans les suspensions de cristaux liquides nématiques
No full textWe establish, as , an asymptotic expansion for the minimal Dirichlet energy of -valued maps outside a finite number of particles of size with fixed centers , under general anchoring conditions at the particle boundaries. Up to a scaling factor, this expansion is of the form\begin{align*}E_\rho = \sum_j \mu_j -4\pi\rho \sum_{i\neq j} \frac{\langle v_i,v_j\rangle}{|x_i-x_j|} +o(\rho)\,,\end{align*}where is the minimal energy after zooming in at scale around each particle, and is a torque determined by the far-field behavior of the corresponding single-particle minimizer.The above expansion highlights Coulomb-like interactions between the particle centers. This agrees with the \textit{electrostatics analogy} commonly used in the physics literature for colloid interactions in nematic liquid crystal. That analogy was pioneered by Brochard and de Gennes in 1970, based on a formal linearization argument.We obtain here for the first time a precise estimate of the energy error introduced by this linearization procedure
Chapitre 7. Pour une évaluation participative : enquêter et s’émanciper ensemble
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Enregistrement de l'épisode 5 de l'Écho des passés
No full text"Podcast"Mon intervention à l'émission Écho des passés porte sur deux parties. La première partie concerne la présentation de mes travaux de thèse portant sur les productions céramiques dans le Sahara central, plus particulièrement dans la région des lacs d'Ounianga au nord du Tchad. La seconde partie porte sur ma position d'archéologue à cheval entre deux continents, notamment l'Europe et l'Afrique. Il s'agit d'expliquer le cadre de coopération scientifique et culturel qui existe entre le Tchad et la France et les difficultés ou les avantages de venir se former en France
Association between herpes simplex virus infection and Alzheimer’s disease biomarkers: analysis within the MAPT trial
No full textInternational audienceIn vitro and animal studies have suggested that inoculation with herpes simplex virus 1 (HSV-1) can lead to amyloid deposits, hyperphosphorylation of tau, and/or neuronal loss. Here, we studied the association between HSV-1 and Alzheimer’s disease biomarkers in humans. Our sample included 182 participants at risk of cognitive decline from the Multidomain Alzheimer Preventive Trial who had HSV-1 plasma serology and an amyloid PET scan. Plasma Aβ42/40 ratio, neurofilament light chain and p-tau181 were also available for a sub-sample of participants. Multivariate linear regressions were performed and stratified by APOE4 genotype. The median age was 74.0 years, 85.2% were infected with HSV-1. Infected participants tended to have a lower cortical amyloid load than uninfected participants (β = -0.08, p = 0.06), especially those suspected of reactivating HSV-1 most frequently (i.e. with a high anti-HSV-1 IgG level; n = 58, β = -0.09 p = 0.04). After stratification, the association was only significant in APOE4 carriers (n = 43, β = -0.21 p = 0.01). No association was found with the plasma biomarkers. The trend toward lower cortical amyloid load in HSV-1-infected participants was unexpected given the pre-existing literature and may be explained either by a modified immune response in HSV-1 infected subjects which could favour the clearance of amyloid deposits or by a selection bias
Smoluchowski Coagulation Equation with a Flux of Dust Particles
No full textWe construct a time-dependent solution to the Smoluchowski coagulation equation with a constant flux of dust particles entering through the boundary at zero. The dust is instantaneously converted into particles and flux solutions have linearly increasing mass. The construction is made for a general class of non-gelling coagulation kernels for which stationary solutions, so-called constant flux solutions, exist. The proof relies on several limiting procedures on a family of solutions of equations with sources supported on ever smaller sizes. In particular, uniform estimates on the fluxes of these solutions are derived in order to control the singularity produced by the flux at zero. We further show that, up to the multiplication by a scalar, flux solutions averaged in size and integrated in time, are bounded from above by the explicit solution, , of the constant flux equation, where is the homogeneity of the bounds of the coagulation rate kernel. Flux solutions are expected to converge to a constant flux solution in the large time limit. We show that this is indeed true in the particular case of the constant kernel with zero initial data
Les secrets dévoilés des verriers : savoirs, gestes et mesures dans les manuels techniques de verrerie du XIXe s.
No full textInternational audienceAt the beginning of the 19th century, the core of glassmaking craft relied on the mastery of manual transformation of materials. Throughout the century, the incorporation of new chemical and physical knowledge became essential for the production processes. However, all the socio-economic values that legitimize glassmakers’ activity still referred to a sort of “secret” of the “art”, mainly related to the unity of body and matter through the mastery of gesture. In an attempt to give a formal restitution, or a normalization of it, during 19th century technical publications like manuals aspired to measure this bodily activity in order to make it a benchmark for measuring, evaluating and teaching how to be a good glassmaker. Using a corpus of technical manuals covering the whole century, this contribution analyses this effort to unreveal the secret of glassmaking by exploring the role of the body as a element of a metrology for explaining, evaluating and teaching glassmaking technique.Alors qu’au début du xixe siècle la maîtrise de la matière par le corps est une qualité qui participe à la bonne gestion de l’atelier verrier, au fil des décennies elle devient un savoir-faire impliquant l’incorporation de procédés et des connaissances technico-scientifiques complexes, chimiques et physiques. L’engagement du corps se place ainsi au cœur de l’ensemble des valorisations socio-économiques qui légitiment l’activité du verrier. L’unité corps-matière est donc soumise à une tentative de restitution formelle, par le biais de publications techniques, qui aspirent à mesurer cette activité corporelle afin d’en faire une référence pour mesurer l’efficacité du travail. À l’aide d’un corpus constitué de manuels techniques couvrant l’intégralité du xixe siècle, cette contribution propose de réfléchir à cet effort de dévoilement du « secret » des verriers à travers l’analyse de la place du corps dans une métrologie ayant le but d’expliquer, évaluer et éventuellement enseigner les techniques de verrerie
« “Entrez dans la danse …” : le ballet des observateurs, spectateurs et personnages dans les Images de Philostrate »
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Towards Transparent Agent-based Models: Visualizing ABM Process Flows from Simulation Traces
No full textInternational audienceOne of the challenges in promoting the Agent-based Modeling approach and communicating this kind of model is making it transparent to stakeholders. Through the years there has been an observed fast development of Agent-Based Models (ABM), especially in modeling social-ecological systems, which quickly raises and heightens the need for a transparent view of these models. Various protocols have been proposed for documenting these models, and calls have been made to ensure open access to the simulation code. However, the lack of consistency in model documentation plus the additional layer required to streamline comprehension and save time in understanding model code does not fully promote a sufficiently transparent view for general users. In response, we present a three-part methodology to make agent-based models transparent. Our objective is to provide a visualization of the ABM processes in a way that closely aligns with the source code withoutderiving the information from the model documentation. The approach is as follows: (1) automatically store execution logs,(2) apply process mining techniques to automatically discover agent processes, and (3) visualize the processes using graph modeling. Simulation logging was implemented within the GAMA platform to ensure compatibility with other models. For graph modeling, we present the final visualization using Business Process Modeling Notation (BPMN), a standard graphical representation for specifying business processes. The resulting visualization is designed to complement the model’s source code and serve as an automatically generated model description. We demonstrate our methodology using various toy models available in GAMA
: BEACHAM, R. C., and H. DENARD. 2023. Living Theatre in the Ancient Roman House: Theatricalism in the Domestic Sphere. Cambridge: Cambridge University Press. Pp. 552. ISBN 978-131-6510-94-0.ANDERSON, M. A. 2023. Space, Movement, and Visibility in Pompeian Houses. London and New York: Routledge. Pp. 276. ISBN 978-147-2485-95-3
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A conceptual framework to assess the emergence, development and viability of rural circular bioclusters
No full textInternational audienceCurrent environmental challenges call for the replacement of fossil resources with bioresources. Bioclusters – innovation ecosystems centered on bioresource use – provide solutions to achieve both environmental and economic objectives by balancing ecosystem preservation with the economic exploitation of bioresources. The literature on the role of bioclusters in transitions emphasizes the need for specific frameworks that account for their unique characteristics. In this context, the aim of this paper is to present an original conceptual framework for analyzing the emergence, development, and viability of rural circular bioclusters by integrating rural development literature with discussions from circular economy and economic geography. The framework outlines three steps to study bioclusters: identifying the resources that form the biocluster (emergence), examining the activation process of these resources and the network of players (development), and detailing governance for resource allocation that balances commodification with heritage-based preservation (viability)