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Molecular determinants of neuroprotection in blood-brain interfaces of the cynomolgus monkey
No full textInternational audienceThe blood-brain barrier (BBB) formed by the cerebral microvessel endothelium and the blood-CSF barrier (BCSFB) formed by the choroid plexus epithelium impact the cerebral bioavailability of drugs and endogenous molecules that contribute to neuroinflammatory and neurodegenerative diseases. Species specificities in tight junction proteins and efflux transporters governing the barrier functions of these interfaces hamper the direct translation of pharmacokinetic and pathophysiological data from rodents to human. We defined the molecular composition of tight junctions and identified the efflux transporters present at the BBB and BCSFB of cynomolgus monkey to assess whether this species is a relevant alternative to rodents. Choroid plexuses, cerebral microvessels, cortex and cerebellum were isolated from adult cynomolgus monkeys, and analysed by RT-qPCR and immunohistochemistry. Results were compared with data available in the literature for rat and human. In monkeys as in rat and human, claudin-5 in the BBB and claudin-1, -2, -3 in the BCSFB were landmark tight junction proteins. ABCB1 was strictly associated with the BBB, and ABCC1 was predominant at the BCSFB compared to the BBB. The monkey, like human, differed from rat by the localization of ABCG2 protein in choroidal vessels, a low expression of ABCC4 and SLC22A8 in the BBB, and the presence of SLC47A1 at the BCSFB. While the main characteristics of brain barriers are common to all three species, cynomolgus monkey and human share specificities in the expression and localization of selected claudins and efflux transporters that are not met in rat
A Physical Model for Accurate Paleotemperature Reconstruction From Fluid Inclusions in Halite
No full textInternational audienceFluid inclusions (FI) trapped in microscopic cavities in halite (NaCl) crystals from evaporitic sedimentary basins are remnants of hypersaline waterbodies. Halite FI provide valuable information on past climate conditions because the density of the enclosed brine can be used for quantitative reconstructions of waterbody temperature at the time of halite precipitation. The classical approach to determine the fluid density in FI is via the liquid-vapor homogenization temperature ( T h,obs ) using FI microthermometry. Recent breakthroughs have the potential to usher in a new era for halite FI in paleoclimate research: new analytical techniques, an equation that predicts the size above which FI deform plastically, an equation of state for multi-electrolyte solutions covering the relevant ranges of temperature, pressure and concentrations, and models that predict the effect of surface tension on T h,obs in constant-volume systems. Against this backdrop we present HaliBubble, a numerical model designed for paleothermometry of Na-K-Mg-Ca-Cl-SO 4 -HCO 3 -H 2 O halite FI that includes the effect of fluid-host interactions on the physico-chemical properties of the FI. HaliBubble allows calculation of (i) the liquid pressure P L and differential stress Δ P in monophasic FI as a function of temperature ( T ), external pressure ( P ext ) and composition ( x ); (ii) the Laplace pressure term Δ T L that corrects for the premature collapse of the vapor bubble due to surface tension; and (iii) the hydrostatic pressure correction term Δ T P that takes into account the water depth at which the halite crystals formed. Compared with an ideal isochoric FI, we find that fluid-host interactions in a halite FI significantly affect P L , Δ T L and Δ T P . We illustrate the model on a halite sample that grew on the floor of the Dead Sea. FI in this halite larger than 27 μm were likely altered by an excessive FI liquid pressure. We calculate a FI entrapment temperature 5.4 °C greater than the average T h,obs , which highlights the relevance of HaliBubble to the paleoenvironmental and paleoclimatic interpretations of halite FI data. Appendix tables and figures provide P L vs. Δ P lim , Δ T L and Δ T P for various chemical compositions. A user interface of HaliBubble is found at https://www.wolframcloud.com/obj/emmanuel.guillerm/HaliBubbleDataProcessing (https://www.wolframcloud.com/obj/emmanuel.guillerm/HaliBubbleDataProcessing)
Un pas-de-côté dans un conflit minier
No full textInternational audienceTandis que l’ours rôde, les habitant·e·s d’une vallée ariégeoise sont assis·e·s sur un trésor et se déchirent. Faut-il rouvrir la mine de Salau et revivre l’époque bénie de l’extraction du tungstène ? Ou accepter la réintroduction de l’ours et poursuivre le chemin de l’ensauvagement ? Le projet minier rejoue l’histoire, l’écologie ravive autrement les conflits. Les paysages miniers ressurgissent. Quant aux habitant·e·s, iels continuent de se faire une place dans la montagne. Jusqu’où aménager la nature ? Là où la liberté n’a d’égale que la contrainte, l’écologie emprunte nécessairement un autre chemin."Un bulldozer et deux-cents bras" est un documentaire de création - en cours de finalisation - entremêlé à une recherche doctorale, coréalisé et coproduit par P. Massé et T. Gionnane. Après le visionnage d’une version en court de finalisation, nous proposons d’orienter la discussion sur la relation entre écriture audiovisuelle et réflexion géographique. Que ce soit à l’écriture, au tournage ou au montage, les choix filmiques résultent d’un doux mélange entre les enjeux du terrain, la réflexion géographique, et les processus subjectifs-identitaires des chercheur·e·s-réalisateur·ice·s.https://ateliervideo.hypotheses.org/122
Invisibiliser les dégâts industriels : le cas du couloir lyonnais de la chimie des années 1960 aux années 1980
No full textInternational audience"Cet article se penche sur les stratégies mises en place par les compagnies pétrochimiques pour répondre aux contestations populaires pour l’environnement dans le couloir lyonnais de la chimie dans les années 1970. Alors que des voix ouvrières et habitantes s’élèvent dès les années 1960 pour contester certains choix industriels, elles disparaissent à la fin des années 1970. Comment des usines générant des accidents répétés et de très fortes pollutions peuvent-elles demeurer, et devenir incontestables, dans des territoires densément peuplés ? Le cas du couloir lyonnais de la chimie démontre que cette présence est le résultat d’un travail actif des industriels pour invisibiliser les pollutions et faire oublier les risques associés à leur activité.
On the Closed-Form of Flow Matching: Generalization Does Not Arise from Target Stochasticity
No full textInternational audienceModern deep generative models can now produce high-quality synthetic samples that are often indistinguishable from real training data. A growing body of research aims to understand why recent methods -such as diffusion and flow matching techniques -generalize so effectively. Among the proposed explanations are the inductive biases of deep learning architectures and the stochastic nature of the conditional flow matching loss. In this work, we rule out the latter -the noisy nature of the loss -as a primary contributor to generalization in flow matching. First, we empirically show that in high-dimensional settings, the stochastic and closed-form versions of the flow matching loss yield nearly equivalent losses. Then, using state-of-the-art flow matching models on standard image datasets, we demonstrate that both variants achieve comparable statistical performance, with the surprising observation that using the closed-form can even improve performance. * Equal contribution
Nanotopographical design and corrosion resistance improvement of Ti40Zr10Cu36Pd14 glassy alloy using alkaline chemical treatment
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Engaging as “Asian women”: the Interweaving of Race and Gender Politicization among Middle-and Upper-Class People of Asian Descent in France
No full textInternational audienceIn France, the stereotype of people of Asian origin - which conventionally refers to people from East and Southeast Asia in the French context - is that they are a discreet and apolitical community. Since the mid-2010s, there has been a growing body of research on the political engagement of people of Asian origin (Chuang, 2013, 2018; Luguern et al. 2023; Luu & Zhou-Thalamy, 2022; Terray, 2012; Wang, 2022; Wang and Madrisotti, 2023). However, little is yet known about the process by which Asian and socially endowed women politicize around themes of race and gender, even less about how experiences of multiple forms of racism and sexism, as well as class resources, jointly participate in structuring the process of their politicization. This paper proposes to fill this gap by looking at the process of politicization of young graduates of Asian origine, first-generation migrants or descendants born in France. Here, politicization refers to the way in which individuals become involved and position themselves in the fundamental conflicts that structure society (Duchesne and Haegel, 2003). The empirical data for this paper come from an action-research project on the experiences of racism and discrimination of young graduates from East and Southeast Asia in France (REACTAsie, October 2020 - September 2022). We focus on the women’s life-stories (20), with a perspective based on the whole corpus (32) to better identify the specificities of women’s trajectories. From a processual perspective on political commitment (Fillieule, 2001), we studied Asian women’s racial and gender socialization processes, their awareness of race and gender relations, and their forms of political commitment. Our study presents three original contributions to the following fields of research: on intersectionality, on the conscientization of race and gender relations, and on the politicization of racialized people. Firstly, our study of Asian women's process of political engagement complexifies the intersectional approach by giving importance to lived events and the temporality of awareness of different social relations over a life course. Next, the study extends the analysis of racialized women's politicization by considering two key social properties of the respondents: class position (of origin and arrival) and migratory generation. By cross-referencing these two social factors, the analysis distinguishes politicization processes between those that first politicize around gender and then around race, and those for whom both processes take place simultaneously. The politicization process is further differentiated between descendants and first-generation migrants, due to the distinct temporality with which the two groups socialize around race. Finally, this work on socially privileged women of Asian origin - given their social position on arrival - differs from previous studies that have often focused on the collective actions of mobilizations and demonstrations organized by socially precarious actors. Often ignored, the everyday strategies of resistance deployed by middle- and upper-class racialized people, illuminated here through the case of women of Asian origin, provide a fine-tuned understanding of the intersecting mechanism of white and male domination, as well as of ordinary forms of resistance in contemporary French society (Karimi, 2020)
Bridging the gap between lab and field sleep studies: a proof-of-concept for studying wild rats in semi-captive environments
No full textInternational audienceSleep is a vital and universal behavior distinct from mere inactivity, yet its ecological role remains poorly understood due to methodological limitations in recording sleep in the wild. Using a small, low-power biologger, collecting brain activity, body movements, and physiology, we recorded key sleep parameters in wild black rats (Rattus rattus) under semi-captive conditions. We developed a rapid (<1 h) surgical procedure using a custom subdermal flexible electrode, providing signal quality comparable to standard cortical electrodes. Our validated semi-captive setup allowed animals to remain in their natural environment with ad libitum food and social contact while minimizing interactions. This protocol enables the study of sleep’s ecological role and the influence of environmental factors on sleep expression, offering insights into its evolution. Additionally, it can help clarify sleep’s central role in the context of global environmental change. By monitoring general behavior and sleep patterns in four wild rats for up to 10 days post-surgery, as well as feeding behavior for over a month, we observed no signs of pain or stress, with sleep patterns stabilizing within 2 days. This approach provides a unique tool to assess sleep variability and flexibility, demonstrating its feasibility for studying sleep in small (<200 g) wild animals
